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12801438 | The use of and search for drugs and dietary supplements derived from plants have accelerated in recent years. Ethnopharmacologists, botanists, microbiologists, and natural-products chemists are combing the Earth for phytochemicals and "leads" which could be developed for treatment of infectious diseases. While 25 to 50% of current pharmaceuticals are derived from plants, none are used as antimicrobials. Traditional healers have long used plants to prevent or cure infectious conditions; Western medicine is trying to duplicate their successes. Plants are rich in a wide variety of secondary metabolites, such as tannins, terpenoids, alkaloids, and flavonoids, which have been found in vitro to have antimicrobial properties. This review attempts to summarize the current status of botanical screening efforts, as well as in vivo studies of their effectiveness and toxicity. The structure and antimicrobial properties of phytochemicals are also addressed. Since many of these compounds are currently available as unregulated botanical preparations and their use by the public is increasing rapidly, clinicians need to consider the consequences of patients self-medicating with these preparations. |
12804937 | Gene expression is a fundamentally stochastic process, with randomness in transcription and translation leading to cell-to-cell variations in mRNA and protein levels. This variation appears in organisms ranging from microbes to metazoans, and its characteristics depend both on the biophysical parameters governing gene expression and on gene network structure. Stochastic gene expression has important consequences for cellular function, being beneficial in some contexts and harmful in others. These situations include the stress response, metabolism, development, the cell cycle, circadian rhythms, and aging. |
12810152 | CONTEXT Hyperhomocysteinemia is caused by genetic and lifestyle influences, including low intakes of folate and vitamin B6. However, prospective data relating intake of these vitamins to risk of coronary heart disease (CHD) are not available. OBJECTIVE To examine intakes of folate and vitamin B6 in relation to the incidence of nonfatal myocardial infarction (MI) and fatal CHD. DESIGN Prospective cohort study. SETTING AND PATIENTS In 1980, a total of 80082 women from the Nurses' Health Study with no previous history of cardiovascular disease, cancer, hypercholesterolemia, or diabetes completed a detailed food frequency questionnaire from which we derived usual intake of folate and vitamin B6. MAIN OUTCOME MEASURE Nonfatal MI and fatal CHD confirmed by World Health Organization criteria. RESULTS During 14 years of follow-up, we documented 658 incident cases of nonfatal MI and 281 cases of fatal CHD. After controlling for cardiovascular risk factors, including smoking and hypertension and intake of alcohol, fiber, vitamin E, and saturated, polyunsaturated, and trans fat, the relative risks (RRs) of CHD between extreme quintiles were 0.69 (95% confidence interval [CI], 0.55-0.87) for folate (median intake, 696 microg/d vs 158 microg/d) and 0.67 (95% CI, 0.53-0.85) for vitamin B6 (median intake, 4.6 mg/d vs 1.1 mg/d). Controlling for the same variables, the RR was 0.55 (95% CI, 0.41-0.74) among women in the highest quintile of both folate and vitamin B6 intake compared with the opposite extreme. Risk of CHD was reduced among women who regularly used multiple vitamins (RR=0.76; 95% CI, 0.65-0.90), the major source of folate and vitamin B6, and after excluding multiple vitamin users, among those with higher dietary intakes of folate and vitamin B6. In a subgroup analysis, compared with nondrinkers, the inverse association between a high-folate diet and CHD was strongest among women who consumed up to 1 alcoholic beverage per day (RR =0.69; 95% CI, 0.49-0.97) or more than 1 drink per day (RR=0.27; 95% CI, 0.13-0.58). CONCLUSION These results suggest that intake of folate and vitamin B6 above the current recommended dietary allowance may be important in the primary prevention of CHD among women. |
12827098 | Despite accumulating evidence suggesting local self-maintenance of tissue macrophages in the steady state, the dogma remains that tissue macrophages derive from monocytes. Using parabiosis and fate-mapping approaches, we confirmed that monocytes do not show significant contribution to tissue macrophages in the steady state. Similarly, we found that after depletion of lung macrophages, the majority of repopulation occurred by stochastic cellular proliferation in situ in a macrophage colony-stimulating factor (M-Csf)- and granulocyte macrophage (GM)-CSF-dependent manner but independently of interleukin-4. We also found that after bone marrow transplantation, host macrophages retained the capacity to expand when the development of donor macrophages was compromised. Expansion of host macrophages was functional and prevented the development of alveolar proteinosis in mice transplanted with GM-Csf-receptor-deficient progenitors. Collectively, these results indicate that tissue-resident macrophages and circulating monocytes should be classified as mononuclear phagocyte lineages that are independently maintained in the steady state. |
12839939 | This paper describes a method for registering and visualizing in real-time the results of transcranial magnetic stimulations (TMS) in physical space on the corresponding anatomical locations in MR images of the brain. The method proceeds in three main steps. First, the patient scalp is digitized in physical space with a magnetic-field digitizer, following a specific digitization pattern. Second, a registration process minimizes the mean square distance between those points and a segmented scalp surface extracted from the magnetic resonance image. Following this registration, the physician can follow the change in coil position in real-time through the visualization interface and adjust the coil position to the desired anatomical location. Third, amplitude of motor evoked potentials can be projected onto the segmented brain in order to create functional brain maps. The registration has subpixel accuracy in a study with simulated data, while we obtain a point to surface root-mean-square error of 1.17/spl plusmn/0.38 mm in a 24 subject study. |
12866641 | Pancreatic ductal adenocarcinomas (PDAs) are characterized by a robust fibroinflammatory response. We show here that this desmoplastic reaction generates inordinately high interstitial fluid pressures (IFPs), exceeding those previously measured or theorized for solid tumors, and induces vascular collapse, while presenting substantial barriers to perfusion, diffusion, and convection of small molecule therapeutics. We identify hyaluronan, or hyaluronic acid (HA), as the primary matrix determinant of these barriers and show that systemic administration of an enzymatic agent can ablate stromal HA from autochthonous murine PDA, normalize IFP, and re-expand the microvasculature. In combination with the standard chemotherapeutic, gemcitabine, the treatment permanently remodels the tumor microenvironment and consistently achieves objective tumor responses, resulting in a near doubling of overall survival. |
12869200 | We performed this meta-analysis of epidemiologic studies to investigate the associations between circulating adiponectin, leptin and adiponectin-leptin (A/L) ratio and endometrial cancer risk. Relevant manuscripts were identified by searching PubMed and ISI Web of Science databases as well as by manual searching the references cited in retrieved manuscripts. Random-effects models were used to estimate summary odds ratio (SOR) and 95% confidence intervals (CIs) for aforementioned associations. Fourteen manuscripts with 13 studies (five nested case-control and eight case-control studies) cumulatively involving a total of 1,963 endometrial cancer cases and 3,503 noncases were included in the analyses. Overall, comparing persons with circulating concentrations of adiponectin, leptin and A/L ratio in the top tertile with persons with concentrations of these biomarkers in the bottom tertile yielded SORs of 0.47 (95% CI: 0.34-0.65; I(2) = 63.7%; n = 13), 2.19 (95% CI: 1.44-3.31; I(2) = 64.2%; n = 7),and 0.45 (95% CI: 0.24-0.86; I(2) = 90.1%; n = 5), respectively. Notably, there was an 18% reduction in risk for per each 5 μg/mL increment in circulating adiponectin concentrations (SOR = 0.82; 95% CI: 0.74-0.90; I(2) = 49%; n = 8). Stratifying by study characteristics and whether these studies considered or adjusted for potential confounders, the findings were robust in the analyses of circulating adiponectin and leptin. No evidence of publication bias was detected. In conclusion, the findings from this meta-analysis suggest that increased circulating adiponectin and A/L ratio or decreased leptin concentrations were associated with reduced risk of endometrial cancer. Further prospective designed studies are warranted to confirm our findings. |
12871002 | We have studied the function of a conserved germline-specific nucleotidyltransferase protein, CDE-1, in RNAi and chromosome segregation in C. elegans. CDE-1 localizes specifically to mitotic chromosomes in embryos. This localization requires the RdRP EGO-1, which physically interacts with CDE-1, and the Argonaute protein CSR-1. We found that CDE-1 is required for the uridylation of CSR-1 bound siRNAs, and that in the absence of CDE-1 these siRNAs accumulate to inappropriate levels, accompanied by defects in both meiotic and mitotic chromosome segregation. Elevated siRNA levels are associated with erroneous gene silencing, most likely through the inappropriate loading of CSR-1 siRNAs into other Argonaute proteins. We propose a model in which CDE-1 restricts specific EGO-1-generated siRNAs to the CSR-1 mediated, chromosome associated RNAi pathway, thus separating it from other endogenous RNAi pathways. The conserved nature of CDE-1 suggests that similar sorting mechanisms may operate in other animals, including mammals. |
12871281 | The reorientation of the T cell microtubule-organizing center (MTOC) toward the antigen-presenting cell enables the directional secretion of cytokines and lytic factors. By single-cell photoactivation of the T cell antigen receptor, we show that MTOC polarization is driven by localized accumulation of diacylglycerol (DAG). MTOC reorientation was closely preceded first by production of DAG and then by recruitment of the microtubule motor protein dynein. Blocking DAG production or disrupting the localization of DAG impaired MTOC recruitment. Localized DAG accumulation was also required for cytotoxic T cell–mediated killing. Furthermore, photoactivation of DAG itself was sufficient to induce transient polarization. Our data identify a DAG-dependent pathway that signals through dynein to control microtubule polarity in T cells. |
12880573 | The plcA gene of Listeria monocytogenes encodes a secreted phosphatidylinositol-specific phospholipase C (Pl-PLC). Recent studies have established that transposon mutations within plcA result in avirulence for mice and pleiotropic effects when examined in tissue-culture models of infection. Genetic analysis reveals that many of the effects of the transposon insertions are due to loss of readthrough transcription from plcA into the downstream gene prfA, which encodes an essential transcription factor of numerous L. monocytogenes virulence genes. Construction of an in-frame deletion within plcA had no effect on expression of prfA thus allowing direct assignment of a role of the Pl-PLC in pathogenesis. Pl-PLC was shown to play a significant role in mediating escape of L. monocytogenes from phagosomes of primary murine macrophages. Interestingly, this defect manifested itself in vivo in the liver but not in the spleen of infected mice. |
12885341 | West Nile virus (WNV) is the most common arthropod-borne flavivirus in the United States; however, the vector ligand(s) that participate in infection are not known. We now show that an Aedes aegypti C-type lectin, mosGCTL-1, is induced by WNV, interacts with WNV in a calcium-dependent manner, and facilitates infection in vivo and in vitro. A mosquito homolog of human CD45 in A. aegypti, designated mosPTP-1, recruits mosGCTL-1 to enable viral attachment to cells and to enhance viral entry. In vivo experiments show that mosGCTL-1 and mosPTP-1 function as part of the same pathway and are critical for WNV infection of mosquitoes. A similar phenomenon was also observed in Culex quinquefasciatus, a natural vector of WNV, further demonstrating that these genes participate in WNV infection. During the mosquito blood-feeding process, WNV infection was blocked in vivo with mosGCTL-1 antibodies. A molecular understanding of flaviviral-arthropod interactions may lead to strategies to control viral dissemination in nature. |
12887068 | Over 70% of diffuse intrinsic pediatric gliomas, an aggressive brainstem tumor, harbor heterozygous mutations that create a K27M amino acid substitution (methionine replaces lysine 27) in the tail of histone H3.3. The role of the H3.3K27M mutation in tumorigenesis is not fully understood. Here, we use a human embryonic stem cell system to model this tumor. We show that H3.3K27M expression synergizes with p53 loss and PDGFRA activation in neural progenitor cells derived from human embryonic stem cells, resulting in neoplastic transformation. Genome-wide analyses indicate a resetting of the transformed precursors to a developmentally more primitive stem cell state, with evidence of major modifications of histone marks at several master regulator genes. Drug screening assays identified a compound targeting the protein menin as an inhibitor of tumor cell growth in vitro and in mice. |
12892137 | Human Rad51 (hRad51), a member of a conserved family of general recombinases, is shown here to have an avid capability to make DNA joints between homologous DNA molecules and promote highly efficient DNA strand exchange of the paired molecules over at least 5.4 kilobase pairs. Furthermore, maximal efficiency of homologous DNA pairing and strand exchange is strongly dependent on the heterotrimeric single-stranded DNA binding factor hRPA and requires conditions that lessen interactions of the homologous duplex with the hRad51-single-stranded DNA nucleoprotein filament. The homologous DNA pairing and strand exchange system described should be valuable for dissecting the action mechanism of hRad51 and for deciphering its functional interactions with other recombination factors. |
12899612 | Although mesenchymal stem cells (MSCs) have been increasingly trialed to treat a variety of diseases, the underlying mechanisms remain still elusive. In this study, human umbilical cord (UC)-derived MSCs were stimulated by hypoxia, and the membrane microvesicles (MVs) in the supernatants were collected by ultracentrifugation, observed under an electron microscope, and the origin was identified with the flow cytometric technique. The results showed that upon hypoxic stimulus, MSCs released a large quantity of MVs of ~100 nm in diameter. The MVs were phenotypically similar to the parent MSCs, except that the majority of them were negative for the receptor of platelet-derived growth factor. DiI-labeling assay revealed that MSC-MVs could be internalized into human UC endothelial cells (UC-ECs) within 8 h after they were added into the culture medium. Carboxyfluorescein succinimidyl ester-labeling technique and MTT test showed that MSC-MVs promoted the proliferation of UC-ECs in a dose-dependent manner. Further, MVs could enhance in vitro capillary network formation of UC-ECs in a Matrigel matrix. In a rat hindlimb ischemia model, both MSCs and MSC-MVs were shown to improve significantly the blood flow recovery compared with the control medium (P<0.0001), as assessed by laser Doppler imaging analysis. These data indicate that MV releasing is one of the major mechanisms underlying the effectiveness of MSC therapy by promoting angiogenesis. |
12909503 | DNA damage encountered by DNA replication forks poses risks of genome destabilization, a precursor to carcinogenesis. Damage checkpoint systems cause cell cycle arrest, promote repair and induce programed cell death when damage is severe. Checkpoints are critical parts of the DNA damage response network that act to suppress cancer. DNA damage and perturbation of replication machinery causes replication stress, characterized by accumulation of single-stranded DNA bound by replication protein A (RPA), which triggers activation of ataxia telangiectasia and Rad3 related (ATR) and phosphorylation of the RPA32, subunit of RPA, leading to Chk1 activation and arrest. DNA-dependent protein kinase catalytic subunit (DNA-PKcs) [a kinase related to ataxia telangiectasia mutated (ATM) and ATR] has well characterized roles in DNA double-strand break repair, but poorly understood roles in replication stress-induced RPA phosphorylation. We show that DNA-PKcs mutant cells fail to arrest replication following stress, and mutations in RPA32 phosphorylation sites targeted by DNA-PKcs increase the proportion of cells in mitosis, impair ATR signaling to Chk1 and confer a G2/M arrest defect. Inhibition of ATR and DNA-PK (but not ATM), mimic the defects observed in cells expressing mutant RPA32. Cells expressing mutant RPA32 or DNA-PKcs show sustained H2AX phosphorylation in response to replication stress that persists in cells entering mitosis, indicating inappropriate mitotic entry with unrepaired damage. |
12922760 | BACKGROUND G-quadruplexes (G4s) are stable non-canonical DNA secondary structures consisting of stacked arrays of four guanines, each held together by Hoogsteen hydrogen bonds. Sequences with the ability to form these structures in vitro, G4 motifs, are found throughout bacterial and eukaryotic genomes. The budding yeast Pif1 DNA helicase, as well as several bacterial Pif1 family helicases, unwind G4 structures robustly in vitro and suppress G4-induced DNA damage in S. cerevisiae in vivo. RESULTS We determined the genomic distribution and evolutionary conservation of G4 motifs in four fission yeast species and investigated the relationship between G4 motifs and Pfh1, the sole S. pombe Pif1 family helicase. Using chromatin immunoprecipitation combined with deep sequencing, we found that many G4 motifs in the S. pombe genome were associated with Pfh1. Cells depleted of Pfh1 had increased fork pausing and DNA damage near G4 motifs, as indicated by high DNA polymerase occupancy and phosphorylated histone H2A, respectively. In general, G4 motifs were underrepresented in genes. However, Pfh1-associated G4 motifs were located on the transcribed strand of highly transcribed genes significantly more often than expected, suggesting that Pfh1 has a function in replication or transcription at these sites. CONCLUSIONS In the absence of functional Pfh1, unresolved G4 structures cause fork pausing and DNA damage of the sort associated with human tumors. |
12932176 | The balance between excitatory and inhibitory synapses is crucial for normal brain function. Wnt proteins stimulate synapse formation by increasing synaptic assembly. However, it is unclear whether Wnt signaling differentially regulates the formation of excitatory and inhibitory synapses. Here, we demonstrate that Wnt7a preferentially stimulates excitatory synapse formation and function. In hippocampal neurons, Wnt7a increases the number of excitatory synapses, whereas inhibitory synapses are unaffected. Wnt7a or postsynaptic expression of Dishevelled-1 (Dvl1), a core Wnt signaling component, increases the frequency and amplitude of miniature excitatory postsynaptic currents (mEPSCs), but not miniature inhibitory postsynaptic currents (mIPSCs). Wnt7a increases the density and maturity of dendritic spines, whereas Wnt7a-Dvl1-deficient mice exhibit defects in spine morphogenesis and mossy fiber-CA3 synaptic transmission in the hippocampus. Using a postsynaptic reporter for Ca(2+)/Calmodulin-dependent protein kinase II (CaMKII) activity, we demonstrate that Wnt7a rapidly activates CaMKII in spines. Importantly, CaMKII inhibition abolishes the effects of Wnt7a on spine growth and excitatory synaptic strength. These data indicate that Wnt7a signaling is critical to regulate spine growth and synaptic strength through the local activation of CaMKII at dendritic spines. Therefore, aberrant Wnt7a signaling may contribute to neurological disorders in which excitatory signaling is disrupted. |
12948892 | Evidence has been accumulated that glioblastoma cells release and exploit glutamate for proliferation and migration by autocrine or paracrine loops through Ca2+-permeable AMPA-type glutamate receptors. Here, we show that Ca2+ signaling mediated by AMPA receptor regulates the growth and motility of glioblastoma cells via activation of Akt. Ca2+ supplied through Ca2+-permeable AMPA receptor phosphorylated Akt at Ser-473, thereby facilitating proliferation and mobility. A dominant-negative form of Akt inhibited cell proliferation and migration accelerated by overexpression of Ca2+-permeable AMPA receptor. In contrast, introduction of a constitutively active form of Akt rescued tumor cells from apoptosis induced by the conversion of Ca2+-permeable AMPA receptor to Ca2+-impermeable receptors by the delivery of GluR2 cDNA. Therefore, Akt functions as downstream effectors for Ca2+-signaling mediated by AMPA receptor in glioblastoma cells. The activation of the glutamate-AMPA receptor-Akt pathway may contribute to the high degree of anaplasia and invasive growth of human glioblastoma. This novel pathway might give an alternative therapeutic target. |
12966719 | CD8 tissue-resident memory T (TRM) cells provide efficient local control of viral infection, but the role of CD4 TRM is less clear. Here, by using parabiotic mice, we show that a preexisting pool of CD4 TRM cells in the genital mucosa was required for full protection from a lethal herpes simplex virus 2 (HSV-2) infection. Chemokines secreted by a local network of macrophages maintained vaginal CD4 TRM in memory lymphocyte clusters (MLCs), independently of circulating memory T cells. CD4 TRM cells within the MLCs were enriched in clones that expanded in response to HSV-2. Our results highlight the need for vaccine strategies that enable establishment of TRM cells for protection from a sexually transmitted virus and provide insights as to how such a pool might be established. |
12991445 | OBJECTIVE To determine the effects of smoking, plasma lipids, lipoproteins, apolipoproteins, and fibrinogen on the patency of saphenous vein femoropopliteal bypass grafts at one year. DESIGN Prospective study of patients with saphenous vein femoropopliteal bypass grafts entered into a multicentre trial. SETTING Surgical wards, outpatient clinics, and home visits coordinated by two tertiary referral centres in London and Birmingham. PATIENTS 157 Patients (mean age 66.6 (SD 8.2) years), 113 with patent grafts and 44 with occluded grafts one year after bypass. MAIN OUTCOME MEASURE Cumulative percentage patency at one year. RESULTS Markers for smoking (blood carboxyhaemoglobin concentration (p less than 0.05) and plasma thiocyanate concentration (p less than 0.01) and plasma concentrations of fibrinogen (p less than 0.001) and apolipoproteins AI (p less than 0.04) and (a) (p less than 0.05) were significantly higher in patients with occluded grafts. Serum cholesterol concentrations were significantly higher in patients with grafts that remained patent one year after bypass (p less than 0.005). Analysis of the smoking markers indicated that a quarter of patients (40) were untruthful in their claims to have stopped smoking. Based on smoking markers, patency of grafts in smokers was significantly lower at one year by life table analysis than in non-smokers (63% v 84%, p less than 0.02). Patency was significantly higher by life table analysis in patients with a plasma fibrinogen concentration below the median than in those with a concentration above (90% v 57%, p less than 0.0002). Surprisingly, increased plasma low density lipoprotein cholesterol concentration was significantly associated with improved patency at one year (85%) at values above the median compared with patency (only 68%) at values in the lower half of the range (p less than 0.02). CONCLUSIONS Plasma fibrinogen concentration was the most important variable predicting graft occlusion, followed by smoking markers. A more forceful approach is needed to stop patients smoking; therapeutic measures to improve patency of vein grafts should focus on decreasing plasma fibrinogen concentration rather than serum cholesterol concentration. |
13000926 | Cold injury is a tissue trauma produced by exposure to freezing temperatures and even brief exposure to a severely cold and windy environment. Rewarming of frozen tissue is associated with blood reperfusion and the simultaneous generation of free oxygen radicals. In this review is discussed the current understanding of the mechanism of action of free oxygen radicals as related to cold injury during rewarming. Decreased energy stores during ischaemia lead to the accumulation of adenine nucleotides and liberation of free fatty acids due to the breakdown of lipid membranes. On rewarming, free fatty acids are metabolized via cyclo-oxygenase and adenine nucleotides are metabolized via the xanthine oxidase pathway. These may be the source of free oxygen radicals. Leukocytes may also play a major role in the pathogenesis of cold injury. Oxygen radical scavengers, such as superoxide dismutase and catalase, may help to reduce the cold induced injury but their action is limited due to the inability readily to cross the plasma membrane. Lipid soluble antioxidants are likely to be more effective scavengers because of their presence in membranes where peroxidative reactions can be arrested. |
13001323 | Chronic feeding on high-calorie diets causes obesity and type 2 diabetes mellitus (T2DM), illnesses that affect hundreds of millions. Thus, understanding the pathways protecting against diet-induced metabolic imbalance is of paramount medical importance. Here, we show that mice lacking SIRT1 in steroidogenic factor 1 (SF1) neurons are hypersensitive to dietary obesity owing to maladaptive energy expenditure. Also, mutant mice have increased susceptibility to developing dietary T2DM due to insulin resistance in skeletal muscle. Mechanistically, these aberrations arise, in part, from impaired metabolic actions of the neuropeptide orexin-A and the hormone leptin. Conversely, mice overexpressing SIRT1 in SF1 neurons are more resistant to diet-induced obesity and insulin resistance due to increased energy expenditure and enhanced skeletal muscle insulin sensitivity. Our results unveil important protective roles of SIRT1 in SF1 neurons against dietary metabolic imbalance. |
13007205 | Stromal fibroblasts can contribute to tumor invasion through the release of matrix metalloproteinases (MMPs). Population studies have suggested that single nucleotide polymorphisms (SNPs) in MMP genes influence levels of expression and may be associated with breast cancer risk and with disease progression. This study directly examined the impact of MMP SNP genotype on the ability of host fibroblasts to promote tumor cell invasion. Primary breast fibroblasts were isolated from patients with (n = 13) or without (n = 19) breast cancer, and their ability to promote breast cancer cell invasion was measured in in vitro invasion assays. Fibroblast invasion-promoting capacity (IPC) was analyzed in relation to donor type (tumor or non-tumor patient), MMP-1, MMP-3, and MMP-9 SNP genotype and MMP activity using independent samples t test and analysis of variance. All statistical tests were two-sided. Tumor-derived fibroblasts promoted higher levels of invasion than normal fibroblasts (p = 0.041). When IPC was related to genotype, higher levels of IPC were generated by tumor fibroblasts with the high-expressing MMP-3 5A/5A genotype compared with the 5A/6A and 6A/6A genotypes (p = 0.05 and 0.07, respectively), and this was associated with enhanced MMP-3 release. The functional importance of MMP-3 was demonstrated by enhanced invasion in the presence of recombinant MMP-3, whereas reduction occurred in the presence of a specific MMP-3 inhibitor. An inverse relationship was demonstrated between fibroblast IPC and the high-expressing MMP-1 genotype (p = 0.031), but no relationship was seen with MMP-9 SNP status. In contrast, normal fibroblasts showed no variation in IPC in relation to MMP genotype, with MMP-3 5A/5A fibroblasts exhibiting significantly lower levels of IPC than their tumor-derived counterparts (p = 0.04). This study has shown that tumor-derived fibroblasts exhibit higher levels of IPC than normal fibroblasts and that the MMP-3 5A/5A genotype contributes to this through enhanced MMP-3 release. Despite a high-expressing genotype, normal fibroblasts do not exhibit higher IPC or enhanced MMP release. This suggests that more complex changes occur in tumor-derived fibroblasts, enabling full expression of the MMP SNP genotype and these possibly are epigenetic in nature. The results do suggest that, in women with breast cancer, a high-expressing MMP-3 genotype may promote tumor progression more effectively. |
13011249 | The hallmarks of cancer comprise six biological capabilities acquired during the multistep development of human tumors. The hallmarks constitute an organizing principle for rationalizing the complexities of neoplastic disease. They include sustaining proliferative signaling, evading growth suppressors, resisting cell death, enabling replicative immortality, inducing angiogenesis, and activating invasion and metastasis. Underlying these hallmarks are genome instability, which generates the genetic diversity that expedites their acquisition, and inflammation, which fosters multiple hallmark functions. Conceptual progress in the last decade has added two emerging hallmarks of potential generality to this list-reprogramming of energy metabolism and evading immune destruction. In addition to cancer cells, tumors exhibit another dimension of complexity: they contain a repertoire of recruited, ostensibly normal cells that contribute to the acquisition of hallmark traits by creating the "tumor microenvironment. " Recognition of the widespread applicability of these concepts will increasingly affect the development of new means to treat human cancer. |
13025574 | High doses of ionizing radiation clearly produce deleterious consequences in humans, including, but not exclusively, cancer induction. At very low radiation doses the situation is much less clear, but the risks of low-dose radiation are of societal importance in relation to issues as varied as screening tests for cancer, the future of nuclear power, occupational radiation exposure, frequent-flyer risks, manned space exploration, and radiological terrorism. We review the difficulties involved in quantifying the risks of low-dose radiation and address two specific questions. First, what is the lowest dose of x- or gamma-radiation for which good evidence exists of increased cancer risks in humans? The epidemiological data suggest that it is approximately 10-50 mSv for an acute exposure and approximately 50-100 mSv for a protracted exposure. Second, what is the most appropriate way to extrapolate such cancer risk estimates to still lower doses? Given that it is supported by experimentally grounded, quantifiable, biophysical arguments, a linear extrapolation of cancer risks from intermediate to very low doses currently appears to be the most appropriate methodology. This linearity assumption is not necessarily the most conservative approach, and it is likely that it will result in an underestimate of some radiation-induced cancer risks and an overestimate of others. |
13048272 | Combinatorial transcription factor (TF) interactions control cellular phenotypes and, therefore, underpin stem cell formation, maintenance, and differentiation. Here, we report the genome-wide binding patterns and combinatorial interactions for ten key regulators of blood stem/progenitor cells (SCL/TAL1, LYL1, LMO2, GATA2, RUNX1, MEIS1, PU.1, ERG, FLI-1, and GFI1B), thus providing the most comprehensive TF data set for any adult stem/progenitor cell type to date. Genome-wide computational analysis of complex binding patterns, followed by functional validation, revealed the following: first, a previously unrecognized combinatorial interaction between a heptad of TFs (SCL, LYL1, LMO2, GATA2, RUNX1, ERG, and FLI-1). Second, we implicate direct protein-protein interactions between four key regulators (RUNX1, GATA2, SCL, and ERG) in stabilizing complex binding to DNA. Third, Runx1(+/-)::Gata2(+/-) compound heterozygous mice are not viable with severe hematopoietic defects at midgestation. Taken together, this study demonstrates the power of genome-wide analysis in generating novel functional insights into the transcriptional control of stem and progenitor cells. |
13070316 | Tumor angiogenesis is an essential process for supplying rapidly growing malignant tissues with essential nutrients and oxygen. An angiogenic switch allows tumor cells to survive and grow, and provides them access to vasculature resulting in metastatic disease. Monocyte-derived macrophages recruited and reprogrammed by tumor cells serve as a major source of angiogenic factors boosting the angiogenic switch. Tumor endothelium releases angiopoietin-2 and further facilitates recruitment of TIE2 receptor expressing monocytes (TEM) into tumor sites. Tumor-associated macrophages (TAM) sense hypoxia in avascular areas of tumors, and react by production of angiogenic factors such as VEGFA. VEGFA stimulates chemotaxis of endothelial cells (EC) and macrophages. In some tumors, TAM appeared to be a major source of MMP9. Elevated expression of MMP9 by TAM mediates extracellular matrix (ECM) degradation and the release of bioactive VEGFA. Other angiogenic factors released by TAM include basic fibroblast growth factor (bFGF), thymidine phosphorylase (TP), urokinase-type plasminogen activator (uPA), and adrenomedullin (ADM). The same factors used by macrophages for the induction of angiogenesis [like vascular endothelial growth factor A (VEGF-A) and MMP9] support lymphangiogenesis. TAM can express LYVE-1, one of the established markers of lymphatic endothelium. TAM support tumor lymphangiogenesis not only by secretion of pro-lymphangiogenic factors but also by trans-differentiation into lymphatic EC. New pro-angiogenic factor YKL-40 belongs to a family of mammalian chitinase-like proteins (CLP) that act as cytokines or growth factors. Human CLP family comprises YKL-40, YKL-39, and SI-CLP. Production of all three CLP in macrophages is antagonistically regulated by cytokines. It was recently established that YKL-40 induces angiogenesis in vitro and in animal tumor models. YKL-40-neutralizing monoclonal antibody blocks tumor angiogenesis and progression. The role of YKL-39 and SI-CLP in tumor angiogenesis and lymphangiogenesis remains to be investigated. |
13071728 | BACKGROUND The World Health Organization (WHO) released revised guidelines in 2015 recommending that all people living with HIV, regardless of CD4 count, initiate antiretroviral therapy (ART) upon diagnosis. However, few studies have projected the global resources needed for rapid scale-up of ART. Under the Health Policy Project, we conducted modeling analyses for 97 countries to estimate eligibility for and numbers on ART from 2015 to 2020, along with the facility-level financial resources required. We compared the estimated financial requirements to estimated funding available. METHODS AND FINDINGS Current coverage levels and future need for treatment were based on country-specific epidemiological and demographic data. Simulated annual numbers of individuals on treatment were derived from three scenarios: (1) continuation of countries' current policies of eligibility for ART, (2) universal adoption of aspects of the WHO 2013 eligibility guidelines, and (3) expanded eligibility as per the WHO 2015 guidelines and meeting the Joint United Nations Programme on HIV/AIDS "90-90-90" ART targets. We modeled uncertainty in the annual resource requirements for antiretroviral drugs, laboratory tests, and facility-level personnel and overhead. We estimate that 25.7 (95% CI 25.5, 26.0) million adults and 1.57 (95% CI 1.55, 1.60) million children could receive ART by 2020 if countries maintain current eligibility plans and increase coverage based on historical rates, which may be ambitious. If countries uniformly adopt aspects of the WHO 2013 guidelines, 26.5 (95% CI 26.0 27.0) million adults and 1.53 (95% CI 1.52, 1.55) million children could be on ART by 2020. Under the 90-90-90 scenario, 30.4 (95% CI 30.1, 30.7) million adults and 1.68 (95% CI 1.63, 1.73) million children could receive treatment by 2020. The facility-level financial resources needed for scaling up ART in these countries from 2015 to 2020 are estimated to be US$45.8 (95% CI 45.4, 46.2) billion under the current scenario, US$48.7 (95% CI 47.8, 49.6) billion under the WHO 2013 scenario, and US$52.5 (95% CI 51.4, 53.6) billion under the 90-90-90 scenario. After projecting recent external and domestic funding trends, the estimated 6-y financing gap ranges from US$19.8 billion to US$25.0 billion, depending on the costing scenario and the U.S. President's Emergency Plan for AIDS Relief contribution level, with the gap for ART commodities alone ranging from US$14.0 to US$16.8 billion. The study is limited by excluding above-facility and other costs essential to ART service delivery and by the availability and quality of country- and region-specific data. CONCLUSIONS The projected number of people receiving ART across three scenarios suggests that countries are unlikely to meet the 90-90-90 treatment target (81% of people living with HIV on ART by 2020) unless they adopt a test-and-offer approach and increase ART coverage. Our results suggest that future resource needs for ART scale-up are smaller than stated elsewhere but still significantly threaten the sustainability of the global HIV response without additional resource mobilization from domestic or innovative financing sources or efficiency gains. As the world moves towards adopting the WHO 2015 guidelines, advances in technology, including the introduction of lower-cost, highly effective antiretroviral regimens, whose value are assessed here, may prove to be "game changers" that allow more people to be on ART with the resources available. |
13083189 | OBJECTIVES Despite recognition of the important influence of environmental determinants on physical activity patterns, minimal empirical research has been done to assess the impact of environmental/contextual determinants of physical activity. This article aims to investigate environmental and sociodemographic determinants of physical activity and inactivity patterns among subpopulations of US adolescents. We define environmental determinants as modifiable factors in the physical environment that impose a direct influence on the opportunity to engage in physical activity. The present research examines environmental and sociodemographic determinants of physical activity and inactivity with the implication that these findings can point toward societal-level intervention strategies for increasing physical activity and decreasing inactivity among adolescents. STUDY DESIGN AND METHODOLOGY The study population consists of nationally representative data from the 1996 National Longitudinal Study of Adolescent Health on 17 766 US adolescents enrolled in US middle and high schools (including 3933 non-Hispanic blacks, 3148 Hispanics, and 1337 Asians). Hours/week of inactivity (TV/video viewing and video/computer games) and times/week of moderate to vigorous physical activity were collected by questionnaire. Outcome variables were moderate to vigorous physical activity and inactivity, which were broken into categories (physical activity: 0-2 times/week, 3-4 times/week, and >/=5 times/week; inactivity: 0-10 hours/week, 11-24 hours/week, and >/=25 hours/week). Sociodemographic and environmental correlates of physical activity and inactivity were used as exposure and control variables and included sex, age, urban residence, participation in school physical education program, use of community recreation center, total reported incidents of serious crime in neighborhood, socioeconomic status, ethnicity, generation of residence in the United States, presence of mother/father in household, pregnancy status, work status, in-school status, region, and month of interview. Logistic regression models of high versus low and medium physical activity and inactivity were used to investigate sex and ethnic interactions in relation to environmental and sociodemographic factors to examine evidence for the potential impact of physical education and recreation programs and sociodemographic factors on physical activity and inactivity patterns. RESULTS Moderate to vigorous physical activity was lower and inactivity higher for non-Hispanic black and Hispanic adolescents. Participation in school physical education programs was considerably low for these adolescents and decreased with age. Participation in daily school physical education (PE) program classes (adjusted odds ratio [AOR]: 2.21; confidence interval [CI]: 1.82-2.68) and use of a community recreation center (AOR: 1.75; CI: 1.56-1.96) were associated with an increased likelihood of engaging in high level moderate to vigorous physical activity. Maternal education was inversely associated with high inactivity patterns; for example, having a mother with a graduate or professional degree was associated with an AOR of.61 (CI:.48-.76) for high inactivity. High family income was associated with increased moderate to vigorous physical activity (AOR: 1.43; CI: 1.22-1.67) and decreased inactivity (AOR:.70; CI:.59-.82). High neighborhood serious crime level was associated with a decreased likelihood of falling in the highest category of moderate to vigorous physical activity (AOR:.77; CI:.66-.91). CONCLUSIONS These results show important associations between modifiable environmental factors, such as participation in school PE and community recreation programs, with activity patterns of adolescents. Despite the marked and significant impact of participation in school PE programs on physical activity patterns of US adolescents, few adolescents participated in such school PE programs; only 21.3% of all adolescents |
13097856 | CONTEXT In 2002, an estimated 877,000 lives were lost worldwide through suicide. Some developed nations have implemented national suicide prevention plans. Although these plans generally propose multiple interventions, their effectiveness is rarely evaluated. OBJECTIVES To examine evidence for the effectiveness of specific suicide-preventive interventions and to make recommendations for future prevention programs and research. DATA SOURCES AND STUDY SELECTION Relevant publications were identified via electronic searches of MEDLINE, the Cochrane Library, and PsychINFO databases using multiple search terms related to suicide prevention. Studies, published between 1966 and June 2005, included those that evaluated preventative interventions in major domains; education and awareness for the general public and for professionals; screening tools for at-risk individuals; treatment of psychiatric disorders; restricting access to lethal means; and responsible media reporting of suicide. DATA EXTRACTION Data were extracted on primary outcomes of interest: suicidal behavior (completion, attempt, ideation), intermediary or secondary outcomes (treatment seeking, identification of at-risk individuals, antidepressant prescription/use rates, referrals), or both. Experts from 15 countries reviewed all studies. Included articles were those that reported on completed and attempted suicide and suicidal ideation; or, where applicable, intermediate outcomes, including help-seeking behavior, identification of at-risk individuals, entry into treatment, and antidepressant prescription rates. We included 3 major types of studies for which the research question was clearly defined: systematic reviews and meta-analyses (n = 10); quantitative studies, either randomized controlled trials (n = 18) or cohort studies (n = 24); and ecological, or population- based studies (n = 41). Heterogeneity of study populations and methodology did not permit formal meta-analysis; thus, a narrative synthesis is presented. DATA SYNTHESIS Education of physicians and restricting access to lethal means were found to prevent suicide. Other methods including public education, screening programs, and media education need more testing. CONCLUSIONS Physician education in depression recognition and treatment and restricting access to lethal methods reduce suicide rates. Other interventions need more evidence of efficacy. Ascertaining which components of suicide prevention programs are effective in reducing rates of suicide and suicide attempt is essential in order to optimize use of limited resources. |
13106686 | Immune sensing of DNA is critical for antiviral immunity but can also trigger autoimmune diseases such as lupus erythematosus (LE). Here we have provided evidence for the involvement of a damage-associated DNA modification in the detection of cytosolic DNA. The oxidized base 8-hydroxyguanosine (8-OHG), a marker of oxidative damage in DNA, potentiated cytosolic immune recognition by decreasing its susceptibility to 3' repair exonuclease 1 (TREX1)-mediated degradation. Oxidizative modifications arose physiologically in pathogen DNA during lysosomal reactive oxygen species (ROS) exposure, as well as in neutrophil extracellular trap (NET) DNA during the oxidative burst. 8-OHG was also abundant in UV-exposed skin lesions of LE patients and colocalized with type I interferon (IFN). Injection of oxidized DNA in the skin of lupus-prone mice induced lesions that closely matched respective lesions in patients. Thus, oxidized DNA represents a prototypic damage-associated molecular pattern (DAMP) with important implications for infection, sterile inflammation, and autoimmunity. |
13108582 | Osteopontin (OPN), a key component of the extracellular matrix, is associated with the fibrotic process during tissue remodeling. OPN and the cytokine interleukin (IL)-18 have been shown to be overexpressed in an array of human cardiac pathologies. In the present study, we determined the role of IL-18 in the regulation of cardiac OPN expression and the subsequent interstitial fibrosis and diastolic dysfunction. We demonstrated parallel increases in IL-18, OPN expression, and interstitial fibrosis in murine models of left ventricular pressure and volume overload. Exogenous recombinant (r)IL-18 administered for 2 wk increased cardiac OPN expression, interstitial fibrosis, and diastolic dysfunction. Stimulation of the T helper (Th)1 lymphocyte phenotype with a selective toll-like receptor (TLR)9 agonist induced cardiac IL-18 and OPN expression, which was associated with increased cardiac fibrillar collagen concentrations and interstitial fibrosis resulting in diastolic dysfunction. rIL-18 induced OPN expression and protein levels in primary of cardiac fibroblast cultures. Conditioned media from TLR9-stimulated T lymphocyte cultures induced IL-18 and OPN expression in cardiac fibroblasts, while blockade of the IL-18 receptor with a neutralizing antibody abolished the increase in OPN expression. Furthermore, a mutation in the transcriptional factor interferon regulatory factor (IRF)1 or IRF1 small interfering RNA (siRNA) resulted in the decreased expression of IL-18 and OPN in cardiac fibroblasts. With pressure overload, IRF1-mutant mice showed downregulation of IL-18 and OPN expression in cardiac tissue, reduced cardiac fibrotic development, and increased left ventricular function compared with wild type. These results provide direct evidence that the induction of IL-18 regulates OPN-mediated cardiac fibrosis and diastolic dysfunction. |
13123189 | BACKGROUND RNA-Seq is revolutionizing the way transcript abundances are measured. A key challenge in transcript quantification from RNA-Seq data is the handling of reads that map to multiple genes or isoforms. This issue is particularly important for quantification with de novo transcriptome assemblies in the absence of sequenced genomes, as it is difficult to determine which transcripts are isoforms of the same gene. A second significant issue is the design of RNA-Seq experiments, in terms of the number of reads, read length, and whether reads come from one or both ends of cDNA fragments. RESULTS We present RSEM, an user-friendly software package for quantifying gene and isoform abundances from single-end or paired-end RNA-Seq data. RSEM outputs abundance estimates, 95% credibility intervals, and visualization files and can also simulate RNA-Seq data. In contrast to other existing tools, the software does not require a reference genome. Thus, in combination with a de novo transcriptome assembler, RSEM enables accurate transcript quantification for species without sequenced genomes. On simulated and real data sets, RSEM has superior or comparable performance to quantification methods that rely on a reference genome. Taking advantage of RSEM's ability to effectively use ambiguously-mapping reads, we show that accurate gene-level abundance estimates are best obtained with large numbers of short single-end reads. On the other hand, estimates of the relative frequencies of isoforms within single genes may be improved through the use of paired-end reads, depending on the number of possible splice forms for each gene. CONCLUSIONS RSEM is an accurate and user-friendly software tool for quantifying transcript abundances from RNA-Seq data. As it does not rely on the existence of a reference genome, it is particularly useful for quantification with de novo transcriptome assemblies. In addition, RSEM has enabled valuable guidance for cost-efficient design of quantification experiments with RNA-Seq, which is currently relatively expensive. |
13179318 | In traditional Kaplan-Meier or Cox regression analysis, usually a risk factor measured at baseline is related to mortality thereafter. During follow-up, however, things may change: either the effect of a fixed baseline risk factor may vary over time, resulting in a weakening or strengthening of associations over time, or the risk factor itself may vary over time. In this paper, short-term versus long-term effects (so-called time-dependent effects) of a fixed baseline risk factor are addressed. An example is presented showing that underweight is a strong risk factor for mortality in dialysis patients, especially in the short run. In contrast, overweight is a risk factor for mortality, which is stronger in the long run than in the short run. In addition, the analysis of how time-varying risk factors (so-called time-dependent risk factors) are related to mortality is demonstrated by paying attention to the pitfall of adjusting for sequelae. The proper analysis of effects over time should be driven by a clear research question. Both kinds of research questions, that is those of time-dependent effects as well those of time-dependent risk factors, can be analyzed with time-dependent Cox regression analysis. It will be shown that using time-dependent risk factors usually implies focusing on short-term effects only. |
13189693 | Neuregulin 1 (NRG1) is a secreted trophic factor that activates the postsynaptic erbB4 receptor tyrosine kinase. Both NRG1 and erbB4 have been repeatedly associated with schizophrenia, but their downstream targets are not well characterized. ErbB4 is highly abundant in interneurons, and NRG1-mediated erbB4 activation has been shown to modulate interneuron function, but the role for NRG1-erbB4 signaling in regulating interneuron dendritic growth is not well understood. Here we show that NRG1/erbB4 promote the growth of dendrites in mature interneurons through kalirin, a major dendritic Rac1-GEF. Recent studies have shown associations of the KALRN gene with schizophrenia. Our data point to an essential role of phosphorylation in kalirin-7's C terminus as the critical site for these effects. As reduced interneuron dendrite length occurs in schizophrenia, understanding how NRG1-erbB4 signaling modulates interneuron dendritic morphogenesis might shed light on disease-related alterations in cortical circuits. |
13223957 | OBJECTIVE The cardinal indication for surgical treatment of gallstones is pain attacks. However, following cholecystectomy, 20% of patients remain symptomatic. It is unclear to what extent post-cholecystectomy symptoms can be ascribed to persistence of preoperative symptoms or to new pathology. The pain and digestive pattern in gallstone patients has not been defined in a recent setting with ultrasonography as the diagnostic method. The aim of this study was to characterize a pain pattern that is typical for gallstone disease and to describe the extent of associated dyspepsia. MATERIAL AND METHODS A total of 220 patients with symptomatic gallstone disease including complicated disease (acute cholecystitis and common bile duct stones) were interviewed using detailed questionnaires to disclose pain patterns and symptoms of indigestion. RESULTS All patients had pain in the right upper quadrant (RUQ) including the upper midline epigastrium. The pain was localized to the right subcostal area in 20% and to the upper epigastrium in 14%, and in the rest (66%) it was more evenly distributed. An area of maximal pain could be defined in 90%. Maximal pain was located under the costal arch in 51% of patients and in the epigastrium in 41%, but in 3% behind the sternum and in 5% in the back. The pain was referred to the back in 63% of the patients. The mean visual analogue scale (VAS) score was very high: 90 mm on a 0-100 scale. A pattern of incipient or low-grade warning pain with a subsequent relatively steady state until subsiding in the same fashion was present in 90% of the patients. An urge to walk around was experienced by 71%. Pain attacks usually occurred in the late evening or at night (77%), with 85% of the attacks lasting for more than one hour and almost never less than half an hour. Sixty-six percent of the patients were intolerant to at least one kind of food, but only 48% to fatty foods. Symptoms of functional indigestion (gastroesophageal reflux, dyspepsia or irritable bowel symptoms) were seen in the vast majority in association with attacks. CONCLUSIONS Gallstone-associated pain follows a certain pattern in the majority of patients. The pain is located in a defined area with a point of maximum intensity, is usually referred, and occurs mainly at night with duration of more than one hour. The majority of patients experience functional indigestion, mainly of the reflux type or dyspepsia. |
13230773 | CONTEXT Population surveys indicate that physical activity levels are low in the United States. One consequence of inactivity, low cardiorespiratory fitness, is an established risk factor for cardiovascular disease (CVD) morbidity and mortality, but the prevalence of cardiorespiratory fitness has not been quantified in representative US population samples. OBJECTIVES To describe the prevalence of low fitness in the US population aged 12 through 49 years and to relate low fitness to CVD risk factors in this population. DESIGN, SETTING, AND PARTICIPANTS Inception cohort study using data from the cross-sectional nationally representative National Health and Nutrition Examination Survey 1999-2002. Participants were adolescents (aged 12-19 years; n = 3110) and adults (aged 20-49 years; n = 2205) free from previously diagnosed CVD who underwent submaximal graded exercise treadmill testing to achieve at least 75% to 90% of their age-predicted maximum heart rate. Maximal oxygen consumption (VO2max) was estimated by measuring the heart rate response to reference levels of submaximal work. MAIN OUTCOME MEASURES Low fitness defined using percentile cut points of estimated VO2max from existing external referent populations; anthropometric and other CVD risk factors measured according to standard methods. RESULTS Low fitness was identified in 33.6% of adolescents (approximately 7.5 million US adolescents) and 13.9% of adults (approximately 8.5 million US adults); the prevalence was similar in adolescent females (34.4%) and males (32.9%) (P = .40) but was higher in adult females (16.2%) than in males (11.8%) (P = .03). Non-Hispanic blacks and Mexican Americans were less fit than non-Hispanic whites. In all age-sex groups, body mass index and waist circumference were inversely associated with fitness; age- and race-adjusted odds ratios of overweight or obesity (body mass index > or =25) ranged from 2.1 to 3.7 (P<.01 for all), comparing persons with low fitness with those with moderate or high fitness. Total cholesterol levels and systolic blood pressure were higher and levels of high-density lipoprotein cholesterol were lower among participants with low vs high fitness. CONCLUSION Low fitness in adolescents and adults is common in the US population and is associated with an increased prevalence of CVD risk factors. |
13242763 | Trophectoderm (TE), the first differentiated cell lineage of mammalian embryogenesis, forms the placenta, a structure unique to mammalian development. The differentiation of TE is a hallmark event in early mammalian development, but molecular mechanisms underlying this first differentiation event remain obscure. Embryonic stem (ES) cells can be induced to differentiate into the TE lineage by forced repression of the POU-family transcription factor, Oct3/4. We show here that this event can be mimicked by overexpression of Caudal-related homeobox 2 (Cdx2), which is sufficient to generate proper trophoblast stem (TS) cells. Cdx2 is dispensable for trophectoderm differentiation induced by Oct3/4 repression but essential for TS cell self-renewal. In preimplantation embryos, Cdx2 is initially coexpressed with Oct3/4 and they form a complex for the reciprocal repression of their target genes in ES cells. This suggests that reciprocal inhibition between lineage-specific transcription factors might be involved in the first differentiation event of mammalian development. |
13244602 | CD133+ populations of human glioblastoma multiforme (GBM) cells are reportedly enriched for tumor stem cells (TSCs) or tumor-initiating cells (TICs). Approximately 40% of freshly isolated GBM specimens, however, do not contain CD133+ tumor cells, raising the possibility that CD133 may not be a universal enrichment marker for GBM TSCs/TICs. Here we demonstrate that stage-specific embryonic antigen 1(SSEA-1/LeX)+ GBM cells fulfill the functional criteria for TSC/TIC, since (1) SSEA-1+ cells are highly tumorigenic in vivo, unlike SSEA-1- cells; (2) SSEA-1+ cells can give rise to both SSEA-1+ and SSEA-1- cells, thereby establishing a cellular hierarchy; and (3) SSEA-1+ cells have self-renewal and multilineage differentiation potentials. A distinct subpopulation of SSEA-1+ cells was present in all but one of the primary GBMs examined (n = 24), and most CD133+ tumor cells were also SSEA-1+, suggesting that SSEA-1 may be a general TSC/TIC enrichment marker in human GBMs. |
13256155 | BACKGROUND Molecularly targeted agents have been reported to have anti-tumour activity for patients whose tumours harbour the matching molecular alteration. These results have led to increased off-label use of molecularly targeted agents on the basis of identified molecular alterations. We assessed the efficacy of several molecularly targeted agents marketed in France, which were chosen on the basis of tumour molecular profiling but used outside their indications, in patients with advanced cancer for whom standard-of-care therapy had failed. METHODS The open-label, randomised, controlled phase 2 SHIVA trial was done at eight French academic centres. We included adult patients with any kind of metastatic solid tumour refractory to standard of care, provided they had an Eastern Cooperative Oncology Group performance status of 0 or 1, disease that was accessible for a biopsy or resection of a metastatic site, and at least one measurable lesion. The molecular profile of each patient's tumour was established with a mandatory biopsy of a metastatic tumour and large-scale genomic testing. We only included patients for whom a molecular alteration was identified within one of three molecular pathways (hormone receptor, PI3K/AKT/mTOR, RAF/MEK), which could be matched to one of ten regimens including 11 available molecularly targeted agents (erlotinib, lapatinib plus trastuzumab, sorafenib, imatinib, dasatinib, vemurafenib, everolimus, abiraterone, letrozole, tamoxifen). We randomly assigned these patients (1:1) to receive a matched molecularly targeted agent (experimental group) or treatment at physician's choice (control group) by central block randomisation (blocks of size six). Randomisation was done centrally with a web-based response system and was stratified according to the Royal Marsden Hospital prognostic score (0 or 1 vs 2 or 3) and the altered molecular pathway. Clinicians and patients were not masked to treatment allocation. Treatments in both groups were given in accordance with the approved product information and standard practice protocols at each institution and were continued until evidence of disease progression. The primary endpoint was progression-free survival in the intention-to-treat population, which was not assessed by independent central review. We assessed safety in any patients who received at least one dose of their assigned treatment. This trial is registered with ClinicalTrials.gov, number NCT01771458. FINDINGS Between Oct 4, 2012, and July 11, 2014, we screened 741 patients with any tumour type. 293 (40%) patients had at least one molecular alteration matching one of the 10 available regimens. At the time of data cutoff, Jan 20, 2015, 195 (26%) patients had been randomly assigned, with 99 in the experimental group and 96 in the control group. All patients in the experimental group started treatment, as did 92 in the control group. Two patients in the control group received a molecularly targeted agent: both were included in their assigned group for efficacy analyses, the patient who received an agent that was allowed in the experimental group was included in the experimental group for the purposes of safety analyses, while the other patient, who received a molecularly targeted agent and chemotherapy, was kept in the control group for safety analyses. Median follow-up was 11·3 months (IQR 5·8-11·6) in the experimental group and 11·3 months (8·1-11·6) in the control group at the time of the primary analysis of progression-free survival. Median progression-free survival was 2·3 months (95% CI 1·7-3·8) in the experimental group versus 2·0 months (1·8-2·1) in the control group (hazard ratio 0·88, 95% CI 0·65-1·19, p=0·41). In the safety population, 43 (43%) of 100 patients treated with a molecularly targeted agent and 32 (35%) of 91 patients treated with cytotoxic chemotherapy had grade 3-4 adverse events (p=0·30). INTERPRETATION The use of molecularly targeted agents outside their indications does not improve progression-free survival compared with treatment at physician's choice in heavily pretreated patients with cancer. Off-label use of molecularly targeted agents should be discouraged, but enrolment in clinical trials should be encouraged to assess predictive biomarkers of efficacy. |
13282296 | CONTEXT Although acute hypoglycemia may be associated with cognitive impairment in children with type 1 diabetes, no studies to date have evaluated whether hypoglycemia is a risk factor for dementia in older patients with type 2 diabetes. OBJECTIVE To determine if hypoglycemic episodes severe enough to require hospitalization are associated with an increased risk of dementia in a population of older patients with type 2 diabetes followed up for 27 years. DESIGN, SETTING, AND PATIENTS A longitudinal cohort study from 1980-2007 of 16,667 patients with a mean age of 65 years and type 2 diabetes who are members of an integrated health care delivery system in northern California. MAIN OUTCOME MEASURE Hypoglycemic events from 1980-2002 were collected and reviewed using hospital discharge and emergency department diagnoses. Cohort members with no prior diagnoses of dementia, mild cognitive impairment, or general memory complaints as of January 1, 2003, were followed up for a dementia diagnosis through January 15, 2007. Dementia risk was examined using Cox proportional hazard regression models, adjusted for age, sex, race/ethnicity, education, body mass index, duration of diabetes, 7-year mean glycated hemoglobin, diabetes treatment, duration of insulin use, hyperlipidemia, hypertension, cardiovascular disease, stroke, transient cerebral ischemia, and end-stage renal disease. RESULTS At least 1 episode of hypoglycemia was diagnosed in 1465 patients (8.8%) and dementia was diagnosed in 1822 patients (11%) during follow-up; 250 patients had both dementia and at least 1 episode of hypoglycemia (16.95%). Compared with patients with no hypoglycemia, patients with single or multiple episodes had a graded increase in risk with fully adjusted hazard ratios (HRs): for 1 episode (HR, 1.26; 95% confidence interval [CI], 1.10-1.49); 2 episodes (HR, 1.80; 95% CI, 1.37-2.36); and 3 or more episodes (HR, 1.94; 95% CI, 1.42-2.64). The attributable risk of dementia between individuals with and without a history of hypoglycemia was 2.39% per year (95% CI, 1.72%-3.01%). Results were not attenuated when medical utilization rates, length of health plan membership, or time since initial diabetes diagnosis were added to the model. When examining emergency department admissions for hypoglycemia for association with risk of dementia (535 episodes), results were similar (compared with patients with 0 episodes) with fully adjusted HRs: for 1 episode (HR, 1.42; 95% CI, 1.12-1.78) and for 2 or more episodes (HR, 2.36; 95% CI, 1.57-3.55). CONCLUSIONS Among older patients with type 2 diabetes, a history of severe hypoglycemic episodes was associated with a greater risk of dementia. Whether minor hypoglycemic episodes increase risk of dementia is unknown. |
13283919 | CRACM1 (also called Orai1) constitutes the pore subunit of store-operated calcium release–activated calcium channels. A point mutation in the gene encoding CRACM1 is associated with severe combined immunodeficiency disease in humans. Here we generated CRACM1-deficient mice in which β-galactosidase activity 'reported' CRACM1 expression. CRACM1-deficient mice were smaller in size. Mast cells derived from CRACM1-deficient mice showed grossly defective degranulation and cytokine secretion, and the allergic reactions elicited in vivo were inhibited in CRACM1-deficient mice. We detected robust CRACM1 expression in skeletal muscles and some regions of the brain, heart and kidney but not in the lymphoid regions of thymus and spleen. In contrast, we found CRACM2 expression to be much higher in mouse T cells. In agreement with those findings, the store-operated calcium influx and development and proliferation of CRACM1-deficient T cells was unaffected. Thus, CRACM1 is crucial in mouse mast cell effector function, but mouse T cell calcium release–activated calcium channels are functional in the absence of CRACM1. |
13290521 | MicroRNAs (miRNAs) are a family of short, non-coding RNA molecules (∼22nt) involved in post-transcriptional control of gene expression. They act via base-pairing with mRNA transcripts that harbour target sequences, resulting in accelerated mRNA decay and/or translational attenuation. Given miRNAs mediate the expression of molecules involved in many aspects of normal cell development and functioning, it is not surprising that aberrant miRNA expression is closely associated with many human diseases. Their pivotal role in driving a range of normal cellular physiology as well as pathological processes has established miRNAs as potential therapeutics, as well as potential diagnostic and prognostic tools in human health. MicroRNA-7 (miR-7) is a highly conserved miRNA which displays restricted spatiotemporal expression during development and in maturity. In humans and mice, mature miR-7 is generated from three different genes, illustrating unexpected redundancy and also the importance of this miRNA in regulating key cellular processes. In this review we examine the expanding role of miR-7 in the context of health, with emphasis on organ differentiation and development, as well as in various mammalian diseases, particularly of the brain, heart, endocrine pancreas and skin, as well as in cancer. The more we learn about miR-7, the more we realise the complexity of its regulation and potential functional application both from a biomarker and therapeutic perspective. |
13293033 | Down syndrome (DS) is the most frequent cause of human congenital mental retardation. Cognitive deficits in DS result from perturbations of normal cellular processes both during development and in adult tissues, but the mechanisms underlying DS etiology remain poorly understood. To assess the ability of induced pluripotent stem cells (iPSCs) to model DS phenotypes, as a prototypical complex human disease, we generated bona fide DS and wild-type (WT) nonviral iPSCs by episomal reprogramming. DS iPSCs selectively overexpressed chromosome 21 genes, consistent with gene dosage, which was associated with deregulation of thousands of genes throughout the genome. DS and WT iPSCs were neurally converted at >95% efficiency and had remarkably similar lineage potency, differentiation kinetics, proliferation, and axon extension at early time points. However, at later time points DS cultures showed a twofold bias toward glial lineages. Moreover, DS neural cultures were up to two times more sensitive to oxidative stress-induced apoptosis, and this could be prevented by the antioxidant N-acetylcysteine. Our results reveal a striking complexity in the genetic alterations caused by trisomy 21 that are likely to underlie DS developmental phenotypes, and indicate a central role for defective early glial development in establishing developmental defects in DS brains. Furthermore, oxidative stress sensitivity is likely to contribute to the accelerated neurodegeneration seen in DS, and we provide proof of concept for screening corrective therapeutics using DS iPSCs and their derivatives. Nonviral DS iPSCs can therefore model features of complex human disease in vitro and provide a renewable and ethically unencumbered discovery platform. |
13322804 | PURPOSE OF REVIEW The availability of a growing number of immunomodulatory medications over the past few years has been associated with various JC virus (JCV)-associated brain syndromes in patients with autoimmune diseases, including multiple sclerosis, Crohn's disease, and psoriasis that had not been previously recognized as predisposing factors for progressive multifocal leukoencephalopathy. This review covers the three novel syndromes discovered in the last decade that are caused by JCV infection of neurons and meningeal cells. RECENT FINDINGS For more than 30 years, JCV was thought to exclusively infect oligodendrocytes and astrocytes in the white matter of the brain of immunosuppressed individuals. We now recognize that JCV-infected glial cells are frequently located at the gray-white matter junction or exclusively within the gray matter causing demyelination in the cortex. Mutations in JCV can trigger a change in tropism leading to involvement of other cell types, such as neurons and meningeal cells, causing clinically distinct entities. These new features of JCV infection provide challenges for clinicians taking care of affected patients and investigators studying the biology of this polyomavirus, its pathogenesis, and tropism. SUMMARY We hope that increasing awareness of these syndromes will lead to early diagnosis, and pave the way for new avenues of research to better understand all aspects of JCV pathogenesis and develop efficient therapies for our patients. However, we need to remain vigilant and open to the possibility that additional JC variants or yet unknown polyomaviruses may also be associated with neurological diseases. |
13329980 | AIMS AND BACKGROUND The PI3 kinase signalling pathway is now accepted as being at least as important as the ras-MAP kinase pathway in cell survival and proliferation, and hence its potential role in cancer is of great interest. The purpose of this review is briefly to examine evidence for an involvement of PI3K in human cancers, discuss the mechanisms by which its activation promotes tumor progression, and consider its utility as a novel target for anticancer therapy. METHODS AND STUDY DESIGN A Medline review of recent literature concerning the role of PI3 kinase in tumor progression--mechanisms of action and clinical implications. RESULTS Evidence is presented that misregulation of the PI3 kinase pathway is a feature of many common cancers, either by loss of the suppressor protein PTEN, or by constitutive activation of PI3 kinase isoforms or downstream elements such as AKT and mTOR. This activation potentiates not only cell survival and proliferation, but also cytoskeletal deformability and motility; key elements in tumor invasion. In addition the PI3K pathway is implicated in many aspects of angiogenesis, including upregulation of angiogenic cytokines due to tumor hypoxia or oncogene activation and endothelial cell responses to them. These cytokines signal though receptors such as VEGF-R, FGF-R and Tie-2 and potentiate processes essential for neoangiogenesis including cell proliferation, migration, differentiation into tubules and "invasion" of these capillary sprouts into extracellular matrix (ECM). CONCLUSIONS A more complete understanding of the role of the PI3 kinase pathway in cancer will lead the way to the development of more potent and selective inhibitors which should be a useful adjunct to conventional therapies, potentially interfering with tumor progression at several pivotal points; in particular cell survival, invasion and angiogenesis. |
13350374 | Mice deficient in the circadian transcription factor BMAL1 (brain and muscle ARNT-like protein) have impaired circadian behavior and demonstrate loss of rhythmicity in the expression of target genes. Here we report that Bmal1(-/-) mice have reduced lifespans and display various symptoms of premature aging including sarcopenia, cataracts, less subcutaneous fat, organ shrinkage, and others. The early aging phenotype correlates with increased levels of reactive oxygen species in some tissues of the Bmal1(-/- )animals. These findings, together with data on CLOCK/BMAL1-dependent control of stress responses, may provide a mechanistic explanation for the early onset of age-related pathologies in the absence of BMAL1. |
13368032 | To develop safer and more effective vectors for gene therapy of X-linked severe combined immunodeficiency (SCID-X1), we have evaluated new self-inactivating lentiviral vectors based on the HIV virus. The CL20i4-hgamma(c)-Revgen vector contains the entire human common gamma chain (gamma(c)) genomic sequence driven by the gamma(c) promoter. The CL20i4-EF1alpha-hgamma(c)OPT vector uses a promoter fragment from the eukaryotic elongation factor alpha (EF1alpha) gene to express a codon-optimized human gamma(c) cDNA. Both vectors contain a 400-bp insulator fragment from the chicken beta-globin locus within the self-inactivating long-terminal repeat. Transduction of bone marrow cells using either of these vectors restored T, B, and natural killer lymphocyte development and function in a mouse SCID-X1 transplantation model. Transduction of human CD34(+) bone marrow cells from SCID-X1 patients with either vector restored T-cell development in an in vitro assay. In safety studies using a Jurkat LMO2 activation assay, only the CL20i4-EF1alpha-hgamma(c)OPT vector lacked the ability to transactivate LMO2 protein expression, whereas the CL20i4-hgamma(c)-Revgen vector significantly activated LMO2 protein expression. In addition, the CL20i4-EF1alpha-hgamma(c)OPT vector has not caused any tumors in transplanted mice. We conclude that the CL20i4-EF1alpha-hgamma(c)OPT vector may be suitable for testing in a clinical trial based on these preclinical demonstrations of efficacy and safety. |
13373629 | BACKGROUND Recent genome-wide association studies (GWAS) have mapped several novel loci influencing blood lipid levels in Caucasians. We sought to explore whether the genetic variants at newly identified lipid-associated loci were associated with CHD susceptibility in a Chinese Han population. METHODOLOGY/PRINCIPAL FINDINGS We conducted a two-stage case-control study in a Chinese Han population. The first-stage, consisting of 1,376 CHD cases and 1,376 sex and age- frequency matched controls, examined 5 novel lipid-associated single-nucleotide polymorphisms (SNPs) identified from GWAS among Caucasians in relation to CHD risk in Chinese. We then validated significant SNPs in the second-stage, consisting of 1,269 cases and 2,745 controls. We also tested associations between SNPs within the five novel loci and blood lipid levels in 4,121 controls. We identified two novel SNPs (rs599839 in CELSR2-PSRC1-SORT1 and rs16996148 in NCAN-CILP2) that were significantly associated with reduced CHD risk in Chinese (odds ratios (95% confidence intervals) in the dominant model 0.76 (0.61-0.90; P = 0.001), 0.67 (0.57-0.77; P = 3.4×10(-8)), respectively). Multiple linear regression analyses using dominant model showed that rs599839 was significantly associated with decreased LDL levels (P = 0.022) and rs16996148 was significantly associated with increased LDL and HDL levels (P = 2.9×10(-4) and 0.001, respectively). CONCLUSIONS/SIGNIFICANCE We identified two novel SNPs (rs599839 and rs16996148) at newly identified lipid-associated loci that were significantly associated with CHD susceptibility in a Chinese Han population. |
13380011 | Partial inhibition of mitochondrial respiratory complex I by rotenone reproduces aspects of Parkinson's disease in rodents. The hypothesis that rotenone enhancement of neuronal cell death is attributable to oxidative stress was tested in an acute glutamate excitotoxicity model using primary cultures of rat cerebellar granule neurons. As little as 5 nM rotenone increased mitochondrial superoxide (O2*-) levels and potentiated glutamate-induced cytoplasmic Ca2+ deregulation, the first irreversible stage of necrotic cell death. However, the potent cell-permeant O2*- trap manganese tetrakis (N-ethylpyridinium-2yl) porphyrin failed to prevent the effects of the inhibitor. The bioenergetic consequences of rotenone addition were quantified by monitoring cell respiration. Glutamate activation of NMDA receptors used the full respiratory capacity of the in situ mitochondria, and >80% of the glutamate-stimulated respiration was attributable to increased cellular ATP demand. Rotenone at 20 nM inhibited basal and carbonyl cyanide p-trifluoromethoxyphenylhydrazone-stimulated cell respiration and caused respiratory failure in the presence of glutamate. ATP synthase inhibition by oligomycin was also toxic in the presence of glutamate. We conclude that the cell vulnerability in the rotenone model of partial complex I deficiency under these specific conditions is primarily determined by spare respiratory capacity rather than oxidative stress. |
13380980 | Many treatments have been proposed for non-resectable primary or secondary hepatic cancer but the results have generally been disappointing. Isolated Hepatic Perfusion (IHP) was first attempted four decades ago but it gained acceptance only recently, after spectacular tumour responses were obtained by isolated limb perfusion with melphalan and tumour necrosis factor (TNF) for melanomas and sarcomas. Surgical isolation of the liver is a technically demanding operation that allows the safe administration of high doses of chemotherapeutics and TNF. Percutaneous techniques using balloon occlusion catheters are simpler but result in higher leakage rates from the perfusion circuit into the systemic circulation. Several phase I-II trials indicate that IHP can yield high tumour response rates, even when there is resistance to systemic chemotherapy. However, no significant advantage in overall survival has been demonstrated so far. IHP offers unique pharmacokinetic advantages for locoregional chemotherapy and biotherapy. It might also allow gene therapy with limited systemic exposure and toxicity. At present, IHP nevertheless remains an experimental treatment modality which should therefore be used in controlled trials only. |
13398997 | The CD28/cytotoxic T-lymphocyte antigen 4 (CTLA-4)blocker belatacept selectively inhibits alloreactive T cell responses but is associated with a high incidence of acute rejection following renal transplantation,which led us to investigate the etiology of belatacept–resistant graft rejection. T cells can differentiate into functionally distinct subsets of memory T cellsthat collectively enable protection against diverse classes of pathogens and can cross-react with allogeneicantigen and mediate graft rejection. T helper 17(Th17) cells are a pro-inflammatory CD4+ lineage that provides immunity to pathogens and are pathogenic in autoimmune disease. We found that T helper 1 (Th1)and Th17 memory compartments contained a similar frequency of divided cells following allogeneic stimulation. Compared to Th1 cells, Th17 memory cells expressed significantly higher levels of the coinhibitory molecule CTLA-4. Stimulation in the presence of belatacept inhibited Th1 responses but augmented Th17 cells due to greater sensitivity to coinhibition by CTLA-4. Th17 cells from renal transplant recipients were resistant to ex vivo CD28/CTLA-4 blockade with belatacept, and an elevated frequency of Th17 memory cells was associated with acute rejection during belatacept therapy. These data highlight important differences in costimulatory and coinhibitory requirements of CD4+ memory subsets, and demonstrate that the heterogeneity of pathogen-derived memory has implications for immunomodulation strategies. |
13445579 | BACKGROUND AND PURPOSE IAs are found in 2.3% of adults; the mean age at detection is 52 years. Prevalence is <0.5% in young adults. Early studies suggest that 10%-50% of patients with aortic coarctation have IAs. Screening recommendations are variable. We sought to examine the prevalence of IAs through screening with MRA. MATERIALS AND METHODS Consecutive patients older than 16 years of age with coarctation undergoing brain MRA between May 1999 and October 2007 were included. MRA was performed by using a 1.5T scanner with a 3D time-of-flight protocol; simultaneous MR imaging was performed of the heart and aorta. Cerebral MRAs were double-reported by a neuroradiologist. Statistics are described as mean ± SD and median ± range. Continuous variables were compared by using Student t tests and Mann-Whitney U tests (categoric variables, by using the Fisher exact test). RESULTS One hundred seventeen MRAs were double-reported. The median age was 29 ± 11 years (range, 16-59 years). IAs were found in 12 patients (10.3%). The mean diameter of IAs was 3.9 mm (range, 2.0-8.0 mm). Patients with aneurysms were older (median, 37 years; range, 16-50 years) than those without (median, 23 years; range, 16-59 years; Z = -2.01, P = .04). Hypertension was more common in those with IAs (IA 83% versus no IA 43%, P = .01). There was no association between ascending aortopathy, bicuspid aortic valves, and IAs. CONCLUSIONS Patients with coarctation have a higher prevalence of IAs, occurring at an earlier age than in population studies. Whether routine screening is appropriate for this group of patients is unclear. Hypertension is likely to be an important pathophysiologic factor. |
13448422 | This review discusses some of the mechanisms inherent in diabetes that predispose patients to increased cardiac morbidity and mortality. Single photon emission computerized tomography or photon emission tomography with radioactive labeled analogues of norepinephrine have shown that cardiac sympathetic dysfunction and incompetence are early and also late abnormalities in patients with Type I (insulin-dependent) and Type II (non-insulin-dependent) diabetes mellitus. Furthermore, myocardial blood flow assessment with photon emission tomography has shown that in patients without myocardial perfusion deficits, endothelial-dependent vasodilatation is severely reduced in relation to cardiac sympathetic dysfunction. In addition, signs of endothelial activation have also been found early in patients with Type I and Type II diabetes in whom vascular disease has not been clinically detected. This activation in conjunction with glycaemic control is important in determining macrovascular mortality. Cardiac sympathetic dysfunction is partially restored to normal with near normalisation of glycaemia. Interpretations. Recently unrecognized “subtle” changes predispose the heart to failure, after ischaemia-induced remodelling, and arteriosclerotic plaques to instability and rupture. These changes act in conjunction with effects, driven by hyperglycaemia and diabetes, on the endothelium of large blood vessels, e. g. on nitric oxide release or on protein kinase-C β activation. Meticulous glucose control early on and rapid recompensation of hyperglycaemia in patients with acute coronary syndrome are part of a successful intensive multifactorial approach to prevent the heart in diabetes converting from ailing to failing. [Diabetologia (2000) 43: 1455–1469] |
13466622 | Metformin has been the mainstay of therapy for diabetes mellitus for many years; however, the mechanistic aspects of metformin action remained ill-defined. Recent advances revealed that this drug, in addition to its glucose-lowering action, might be promising for specifically targeting metabolic differences between normal and abnormal metabolic signalling. The knowledge gained from dissecting the principal mechanisms by which metformin works can help us to develop novel treatments. The centre of metformin's mechanism of action is the alteration of the energy metabolism of the cell. Metformin exerts its prevailing, glucose-lowering effect by inhibiting hepatic gluconeogenesis and opposing the action of glucagon. The inhibition of mitochondrial complex I results in defective cAMP and protein kinase A signalling in response to glucagon. Stimulation of 5′-AMP-activated protein kinase, although dispensable for the glucose-lowering effect of metformin, confers insulin sensitivity, mainly by modulating lipid metabolism. Metformin might influence tumourigenesis, both indirectly, through the systemic reduction of insulin levels, and directly, via the induction of energetic stress; however, these effects require further investigation. Here, we discuss the updated understanding of the antigluconeogenic action of metformin in the liver and the implications of the discoveries of metformin targets for the treatment of diabetes mellitus and cancer. |
13481731 | OBJECTIVES This study was designed to determine if women are more likely than men to have heart failure (HF) with preserved systolic function after adjustment for potential confounders, including age. BACKGROUND Although prior evidence suggests an independent association between female gender and preserved left ventricular systolic function (LVSF) in patients with HF, existing studies are limited by referral biases, small sample sizes, or the inability to adjust for a wide range of potential confounding variables. METHODS This is a cross-sectional study using data from retrospective medical chart abstraction of a national sample of Medicare beneficiaries hospitalized with the principal discharge diagnosis of HF in acute-care nongovernmental hospitals in the U.S. between April 1998 and March 1999. Patients were eligible for this analysis if they were age 65 years or older, had documentation of LVSF, and corroboration of the diagnosis of HF. We used multivariable logistic regression to identify the correlates of preserved LVSF, which was defined as qualitatively normal function or quantitatively reported ejection fraction > or =0.50. Stratified regressions by gender were performed to identify significant interactions. RESULTS Of the 19,710 patients in the analysis, preserved LVSF was present in 6,700 (35%), 79% of whom were women. In contrast, among the 12,956 patients with impaired LVSF, only 49% were women. Patients with preserved LVSF were 1.5 years older than those with impaired LVSF. After adjustment for age and other patient factors, female gender remained strongly associated with preserved LVSF (calculated risk ratio = 1.71; 95% confidence interval 1.63 to 1.78). The association was consistent in all age groups, and was similar in patients with or without coronary artery disease, hypertension, pulmonary disease, renal insufficiency, or atrial fibrillation. CONCLUSIONS In elderly patients hospitalized with HF, preserved systolic function is primarily a condition of women, independent of important demographic and clinical characteristics. |
13481880 | Tissue regeneration requires dynamic cellular adaptation to the wound environment. It is currently unclear how this is orchestrated at the cellular level and how cell fate is affected by severe tissue damage. Here we dissect cell fate transitions during colonic regeneration in a mouse dextran sulfate sodium (DSS) colitis model, and we demonstrate that the epithelium is transiently reprogrammed into a primitive state. This is characterized by de novo expression of fetal markers as well as suppression of markers for adult stem and differentiated cells. The fate change is orchestrated by remodeling the extracellular matrix (ECM), increased FAK/Src signaling, and ultimately YAP/TAZ activation. In a defined cell culture system recapitulating the extracellular matrix remodeling observed in vivo, we show that a collagen 3D matrix supplemented with Wnt ligands is sufficient to sustain endogenous YAP/TAZ and induce conversion of cell fate. This provides a simple model for tissue regeneration, implicating cellular reprogramming as an essential element. |
13494853 | The abbreviated name, 'mfold web server', describes a number of closely related software applications available on the World Wide Web (WWW) for the prediction of the secondary structure of single stranded nucleic acids. The objective of this web server is to provide easy access to RNA and DNA folding and hybridization software to the scientific community at large. By making use of universally available web GUIs (Graphical User Interfaces), the server circumvents the problem of portability of this software. Detailed output, in the form of structure plots with or without reliability information, single strand frequency plots and 'energy dot plots', are available for the folding of single sequences. A variety of 'bulk' servers give less information, but in a shorter time and for up to hundreds of sequences at once. The portal for the mfold web server is http://www.bioinfo.rpi.edu/applications/mfold. This URL will be referred to as 'MFOLDROOT'. |
13496853 | PURPOSE The aim of this study was to update reference data of handgrip strength for healthy adults of both genders spanning a wide age range and to analyze possible factors of influence. METHODS Intraindividual and interindividual variations of grip strength and their relation to several anthropometric factors were analyzed in a standardized manner for 769 healthy adults (women, n = 403; men, n = 366) aged between 20 years and 95 years. Measurements were done in neutral position of arm, forearm, and wrist on setting II of a Baseline digital hydraulic dynamometer (NexGen Ergonomics Inc. Quebec, Canada). RESULTS Mean strength was about 41% less in women (right 29 kg; left 27 kg) than in men (right 49 kg; left 47 kg) resulting in a ratio of left to right hand slightly above .95 in both genders. During the course of life, hand strength develops comparably in both genders peaking at 35 years of age and decreasing continuously further on. Anthropometric variables such as forearm circumference and length, hand size, or body mass showed a positive correlation with grip strength. Body mass index, type of work, and hand dominance showed only a partial positive correlation or no correlation with grip strength. Gender and age, followed by parameters representing body length and obesity, were observed to have the highest predictive value for handgrip strength and were therefore entered into the generation of prediction equations. CONCLUSIONS We recommend side adjustment of measured values for intraindividual comparison and inclusion of information regarding anthropometric characteristics, as well as using gender- and age-adjusted reference values, whereas hand dominance can be neglected. The regression equations we generated might prove to be useful for clinicians or for those who use normative values within software to provide more accurate predictions of strength scores for specific applications. |
13509809 | The bone marrow (BM) niche comprises multiple cell types that regulate hematopoietic stem/progenitor cell (HSPC) migration out of the niche and into the circulation. Here, we demonstrate that osteocytes, the major cellular component of mature bone, are regulators of HSPC egress. Granulocyte colony-stimulating factor (G-CSF), used clinically to mobilize HSPCs, induces changes in the morphology and gene expression of the osteocytic network that precedes changes in osteoblasts. This rapid response is likely under control of the sympathetic nervous system, since osteocytes express the β2-adrenergic receptor and surgical sympathectomy prevents it. Mice with targeted ablation of osteocytes or a disrupted osteocyte network have comparable numbers of HSPCs in the BM but fail to mobilize HSPCs in response to G-CSF. Taken together, these results indicate that the BM/bone niche interface is critically controlled from inside of the bone matrix and establish an important physiological role for skeletal tissues in hematopoietic function. |
13515165 | BACKGROUND It is commonly written that more patients wish to die at home than currently achieve this. However, the evidence for preferences for place of terminal care and death has not been systematically reviewed. AIM To carry out a systematic literature review of the preferences for place of care and death among advanced cancer patients. METHOD Studies were identified using systematic database searches of MEDLINE (1966-1999), PsychLit (1974-1999), and Bath Information Data Service (BIDS) (1981-1999). Studies were assessed and data extracted and synthesises following the NHS Centre for Reviews and Dissemination guidelines, grading studies according to design and rigor of methods. Studies of preferences in the general population and of groups including cancer patients and/or their caregivers were included. RESULTS Eighteen studies determining preferences in either the general population or groups including cancer patients were identified. Views were obtained prospectively and retrospectively from patients, the general population, families, and professionals. Respondents indicated preferences for home death (range 49%-100%), except one study of patients in the care of a continuing care team in London where only 25%-29% of patients wanted a home death, and inpatient hospice was the most favored option. However, the response rate of this study was not known. Among the general public there was a higher preference for inpatient hospice care among in people with recent experience of a close friend or relative's death or dying. Where the views of patients, families, and professionals were compared, all respondents broadly agreed although patients expressed the strongest home preferences. Only 2 of the studies provided longitudinal data, and 9 of the 18 had major deficits in design or reporting, such as poor or unknown response rate, unclear or unsystematic methods of eliciting preferences or other sample or measurement bias. However, sensitivity analysis of only the more robust and larger studies did not alter the finding of a preference for home care at the end of life in over 50% of patients. CONCLUSIONS Home care is the most common preference, with inpatient hospice care as second preference in advanced illness. Meeting these preferences could be important outcomes for services. Study designs in this area need to be improved. |
13519661 | Background Checkpoint kinase 2 (CHEK2) averts cancer development by promoting cell cycle arrest and activating DNA repair in genetically damaged cells. Previous investigation has established a role for the CHEK2 gene in breast cancer aetiology, but studies have largely been limited to the rare 1100delC mutation. Whether common polymorphisms in this gene influence breast cancer risk remains unknown. In this study, we aimed to assess the importance of common CHEK2 variants on population risk for breast cancer by capturing the majority of diversity in the gene using haplotype tagging single nucleotide polymorphisms (tagSNPs). Methods and Findings We analyzed 14 common SNPs spanning 52 kilobases (kb) of the CHEK2 gene in 92 Swedish women. Coverage evaluation indicated that these typed SNPs would efficiently convey association signal also from untyped SNPs in the same region. Six of the 14 SNPs predicted well both the haplotypic and single SNP variations within CHEK2. We genotyped these six tagSNPs in 1,577 postmenopausal breast cancer cases and 1,513 population controls, but found no convincing association between any common CHEK2 haplotype and breast cancer risk. The 1100delC mutation was rare in our Swedish population—0.7% in cases and 0.4% in controls— with a corresponding odds ratio for carriers versus noncarriers of 2.26 (95% confidence interval, 0.99–5.15). Estimates of the population frequency and the odds ratio of 1100delC indicate that our sample is representative of a Northern European population. |
13552682 | In eukaryotes, accurate protein synthesis relies on a family of translational GTPases that pair with specific decoding factors to decipher the mRNA code on ribosomes. We present structures of the mammalian ribosome engaged with decoding factor⋅GTPase complexes representing intermediates of translation elongation (aminoacyl-tRNA⋅eEF1A), termination (eRF1⋅eRF3), and ribosome rescue (Pelota⋅Hbs1l). Comparative analyses reveal that each decoding factor exploits the plasticity of the ribosomal decoding center to differentially remodel ribosomal proteins and rRNA. This leads to varying degrees of large-scale ribosome movements and implies distinct mechanisms for communicating information from the decoding center to each GTPase. Additional structural snapshots of the translation termination pathway reveal the conformational changes that choreograph the accommodation of decoding factors into the peptidyl transferase center. Our results provide a structural framework for how different states of the mammalian ribosome are selectively recognized by the appropriate decoding factor⋅GTPase complex to ensure translational fidelity. |
13583521 | According to dogma, initiator caspases are activated through proximity-induced homodimerization, but some studies infer that during apoptosis caspase-9 may instead form a holoenzyme with the Apaf-1 apoptosome. Using several biochemical approaches, including a novel site-specific crosslinking technique, we provide the first direct evidence that procaspase-9 homodimerizes within the apoptosome, markedly increasing its avidity for the complex and inducing selective intramolecular cleavage at Asp-315. Remarkably, however, procaspase-9 could also bind via its small subunit to the NOD domain in Apaf-1, resulting in the formation of a heterodimer that more efficiently activated procaspase-3. Following cleavage, the intersubunit linker (and associated conformational changes) in caspase-9-p35/p12 inhibited its ability to form homo- and heterodimers, but feedback cleavage by caspase-3 at Asp-330 removed the linker entirely and partially restored activity to caspase-9-p35/p10. Thus, the apoptosome mediates the formation of caspase-9 homo- and heterodimers, both of which are impacted by cleavage and contribute to its overall function. |
13583615 | During meiosis I, kinetochores of sister chromatids are juxtaposed or fused and mono-orient, while homologous chromosomes that are paired by chiasmata (bivalents) have to biorient. In the absence of chiasmata, biorientation of sister chromatids (univalents), which carries a risk of aneuploidy, has been occasionally detected in several species, including humans. We show in fission yeast that biorientation of fused sister kinetochores predominates during early prometaphase I. Without chiasmata, this undesirable biorientation of univalents persists and eventually evades the spindle assembly checkpoint, provoking abnormal anaphase. When univalents are connected by chiasmata or by an artificial tether, this erroneous attachment is converted to monopolar attachment and stabilized. This stabilization is apparently achieved by a chromosome configuration that brings kinetochores to the outer edge of the bivalent, while bringing Aurora B, a destabilizer of kinetochore-microtubule attachment, inward. Our results elucidate how chiasmata favor biorientation of bivalents over that of univalents at meiosis I. |
13613916 | Glucose is the primary source of energy for the budding yeast Saccharomyces cerevisiae. Although yeast cells can utilize a wide range of carbon sources, presence of glucose suppresses molecular activities involved in the use of alternate carbon sources as well as it represses respiration and gluconeogenesis. This dominant effect of glucose on yeast carbon metabolism is coordinated by several signaling and metabolic interactions that mainly regulate transcriptional activity but are also effective at post-transcriptional and post-translational levels. This review describes effects of glucose repression on yeast carbon metabolism with a focus on roles of the Snf3/Rgt2 glucose-sensing pathway and Snf1 signal transduction in establishment and relief of glucose repression. |
13619127 | OBJECTIVE To assess the risks of amputation, blindness, severe kidney failure, hyperglycaemia, and hypoglycaemia in patients with type 2 diabetes associated with prescribed diabetes drugs, particularly newer agents including gliptins or glitazones (thiazolidinediones). DESIGN Open cohort study in primary care. SETTING 1243 practices contributing data to the QResearch database in England. PARTICIPANTS 469,688 patients with type 2 diabetes aged 25-84 years between 1 April 2007 and 31 January 2015. EXPOSURES Hypoglycaemic agents (glitazones, gliptins, metformin, sulphonylureas, insulin, and other) alone and in combination. MAIN OUTCOME MEASURES First recorded diagnoses of amputation, blindness, severe kidney failure, hyperglycaemia, and hypoglycaemia recorded on patients' primary care, mortality, or hospital records. Cox models estimated hazard ratios for diabetes treatments adjusting for potential confounders. RESULTS 21,308 (4.5%) and 32,533 (6.9%) patients received prescriptions for glitazones and gliptins during follow-up, respectively. Compared with non-use, glitazones were associated with a decreased risk of blindness (adjusted hazard ratio 0.71, 95% confidence interval 0.57 to 0.89; rate 14.4 per 10,000 person years of exposure) and an increased risk of hypoglycaemia (1.22, 1.10 to 1.37; 65.1); gliptins were associated with a decreased risk of hypoglycaemia (0.86, 0.77 to 0.96; 45.8). Although the numbers of patients prescribed gliptin monotherapy or glitazones monotherapy were relatively low, there were significantly increased risks of severe kidney failure compared with metformin monotherapy (adjusted hazard ratio 2.55, 95% confidence interval 1.13 to 5.74). We found significantly lower risks of hyperglycaemia among patients prescribed dual therapy involving metformin with either gliptins (0.78, 0.62 to 0.97) or glitazones (0.60, 0.45 to 0.80) compared with metformin monotherapy. Patients prescribed triple therapy with metformin, sulphonylureas, and either gliptins (adjusted hazard ratio 5.07, 95% confidence interval 4.28 to 6.00) or glitazones (6.32, 5.35 to 7.45) had significantly higher risks of hypoglycaemia than those prescribed metformin monotherapy, but these risks were similar to those involving dual therapy with metformin and sulphonylureas (6.03, 5.47 to 6.63). Patients prescribed triple therapy with metformin, sulphonylureas, and glitazones had a significantly reduced risk of blindness compared with metformin monotherapy (0.67, 0.48 to 0.94). CONCLUSIONS We have found lower risks of hyperglycaemia among patients prescribed dual therapy involving metformin with either gliptins or glitazones compared with metformin alone. Compared with metformin monotherapy, triple therapy with metformin, sulphonylureas, and either gliptins or glitazones was associated with an increased risk of hypoglycaemia, which was similar to the risk for dual therapy with metformin and sulphonylureas. Compared with metformin monotherapy, triple therapy with metformin, sulphonylureas, and glitazones was associated with a reduced risk of blindness. These results, while subject to residual confounding, could have implications for the prescribing of hypoglycaemic drugs. |
13624704 | The efficacy, safety and resource implications of a single intravenous dose of ondansetron (0.1 mg.kg-1, maximum 4 mg) were assessed in a multinational, multicentre, randomized, double-blind, placebo-controlled trial of 427 children aged 1-12 years, undergoing tonsillectomy with/without adenoidectomy. Emesis (retching and/or vomiting) and nausea were analysed separately. Significantly more ondansetron-treated children had no episodes of emesis (127/212 (60%) vs 100/215 (47%); P = 0.004) and experienced no postoperative nausea (135/211 (64%) vs 108/213 (51%); P = 0.004) in the first 24 h. Ondansetron also reduced the number of emetic episodes (P < 0.001), the time to the first emetic episode (P < 0.001) and overall nausea severity (P = 0.003). Significantly fewer ondansetron-treated children were rescued or withdrawn from the study (5% vs 10%; P = 0.042). Fewer ondansetron-treated patients required nursing intervention (34% vs 45%; P = 0.007) and the average intervention time was significantly shorter (4.6 vs 8.1 minutes; P = 0.001). Resources used to manage PONV were significantly reduced by ondansetron (43% vs 57%; P = 0.014). |
13639330 | Nuclear receptors undergo ligand-dependent conformational changes that are required for corepressor-coactivator exchange, but whether there is an actual requirement for specific epigenetic landmarks to impose ligand dependency for gene activation remains unknown. Here we report an unexpected and general strategy that is based on the requirement for specific cohorts of inhibitory histone methyltransferases (HMTs) to impose gene-specific gatekeeper functions that prevent unliganded nuclear receptors and other classes of regulated transcription factors from binding to their target gene promoters and causing constitutive gene activation in the absence of stimulating signals. This strategy, based at least in part on an HMT-dependent inhibitory histone code, imposes a requirement for specific histone demethylases, including LSD1, to permit ligand- and signal-dependent activation of regulated gene expression. These events link an inhibitory methylation component of the histone code to a broadly used strategy that circumvents pathological constitutive gene induction by physiologically regulated transcription factors. |
13651792 | IRGM, a human immunity-related GTPase, confers autophagic defence against intracellular pathogens by an unknown mechanism. Here, we report an unexpected mode of IRGM action. IRGM demonstrated differential affinity for the mitochondrial lipid cardiolipin, translocated to mitochondria, affected mitochondrial fission and induced autophagy. Mitochondrial fission was necessary for autophagic control of intracellular mycobacteria by IRGM. IRGM influenced mitochondrial membrane polarization and cell death. Overexpression of IRGMd, but not IRGMb splice isoforms, caused mitochondrial depolarization and autophagy-independent, but Bax/Bak-dependent, cell death. By acting on mitochondria, IRGM confers autophagic protection or cell death, explaining IRGM action both in defence against tuberculosis and in the damaging inflammation caused by Crohn's disease. |
13714201 | Aims The gut microbiome influences metabolic syndrome (MetS) and inflammation and is therapeutically modifiable. Arterial stiffness is poorly correlated with most traditional risk factors. Our aim was to examine whether gut microbial composition is associated with arterial stiffness. Methods and results We assessed the correlation between carotid-femoral pulse wave velocity (PWV), a measure of arterial stiffness, and gut microbiome composition in 617 middle-aged women from the TwinsUK cohort with concurrent serum metabolomics data. Pulse wave velocity was negatively correlated with gut microbiome alpha diversity (Shannon index, Beta(SE)= -0.25(0.07), P = 1 × 10-4) after adjustment for covariates. We identified seven operational taxonomic units associated with PWV after adjusting for covariates and multiple testing-two belonging to the Ruminococcaceae family. Associations between microbe abundances, microbe diversity, and PWV remained significant after adjustment for levels of gut-derived metabolites (indolepropionate, trimethylamine oxide, and phenylacetylglutamine). We linearly combined the PWV-associated gut microbiome-derived variables and found that microbiome factors explained 8.3% (95% confidence interval 4.3-12.4%) of the variance in PWV. A formal mediation analysis revealed that only a small proportion (5.51%) of the total effect of the gut microbiome on PWV was mediated by insulin resistance and visceral fat, c-reactive protein, and cardiovascular risk factors after adjusting for age, body mass index, and mean arterial pressure. Conclusions Gut microbiome diversity is inversely associated with arterial stiffness in women. The effect of gut microbiome composition on PWV is only minimally mediated by MetS. This first human observation linking the gut microbiome to arterial stiffness suggests that targeting the microbiome may be a way to treat arterial ageing. |
13717103 | INTRODUCTION Mutations in the FUS gene have been shown to be a rare cause of amyotrophic lateral sclerosis (ALS-FUS) and whilst well documented clinically and genetically there have been relatively few neuropathological studies. Recent work suggested a possible correlation between pathological features such as frequency of basophilic inclusions in neurons and rate of clinical decline, other studies have revealed a discrepancy between the upper motor neuron features detected clinically and the associated pathology. The purpose of this study was to describe the pathological features associated with more recently discovered FUS mutations and reinvestigate those with well recognised mutations in an attempt to correlate the pathology with mutation and/or clinical phenotype. The brains and spinal cords of seven cases of ALS-FUS were examined neuropathologically, including cases with the newly described p. K510E mutation and a case with both a known p. P525L mutation in the FUS gene and a truncating p. Y374X mutation in the TARDBP gene. RESULTS The neuropathology in all cases revealed basophilic and FUS inclusions in the cord. The density and type of inclusions varied markedly between cases, but did not allow a clear correlation with clinical progression. Only one case showed significant motor cortical pathology despite the upper motor neuron clinical features being evident in 4 patients. The case with both a FUS and TARDBP mutation revealed FUS positive inclusions but no TDP-43 pathology. Instead there were unusual p62 positive, FUS negative neuronal and glial inclusions as well as dot-like neurites. CONCLUSIONS The study confirms cases of ALS-FUS to be mainly a lower motor neuron disease and to have pathology that does not appear to neatly correlate with clinical features or genetics. Furthermore, the case with both a FUS and TARDBP mutation reveals an intriguing pathological profile which at least in part involves a very unusual staining pattern for the ubiquitin-binding protein p62. |
13732033 | OBJECTIVES To investigate the views of parents, clinicians, and children pertaining to prescribing decisions for acute childhood infection in primary care. METHODS A systematic review of qualitative studies. Meta-ethnographic methods were used, with data drawn from the primary studies in an interpretive analysis. RESULTS A total of 15 studies met the inclusion criteria. The literature was dominated by concerns about antibiotic over-prescription. Children's views were not reported. Clinicians prescribed antibiotics when they felt pressured by parents or others (e.g. employers) to do so, when they believed there was a clear clinical indication, but also when they felt uncertain of clinical or social outcomes they prescribed "just in case". Parents wanted antibiotics when they felt they would improve the current illness, and when they felt pressure from daycare providers or employers. Clinicians avoided antibiotics when they were concerned about adverse reactions or drug resistance, when certain they were not indicated, and when there was no perceived pressure from parents. Parents also wished to avoid adverse effects of antibiotics, and did not want antibiotics when they would not relieve current symptoms. Some parents preferred to avoid medication altogether. Within paediatric consultations, parents sought a medical evaluation and decision. Primary care clinicians want satisfied parents and short consultations. CONCLUSIONS Antibiotic prescriptions for childhood infections in primary care often result from "just in case" prescribing. These findings suggest that interventions which reduce clinician uncertainty regarding social or clinical outcomes and provide strategies to meet parents' needs within a short consultation are most likely to reduce antibiotic prescribing. |
13734012 | OBJECTIVES To carry out a further survey of archived appendix samples to understand better the differences between existing estimates of the prevalence of subclinical infection with prions after the bovine spongiform encephalopathy epizootic and to see whether a broader birth cohort was affected, and to understand better the implications for the management of blood and blood products and for the handling of surgical instruments. DESIGN Irreversibly unlinked and anonymised large scale survey of archived appendix samples. SETTING Archived appendix samples from the pathology departments of 41 UK hospitals participating in the earlier survey, and additional hospitals in regions with lower levels of participation in that survey. SAMPLE 32,441 archived appendix samples fixed in formalin and embedded in paraffin and tested for the presence of abnormal prion protein (PrP). RESULTS Of the 32,441 appendix samples 16 were positive for abnormal PrP, indicating an overall prevalence of 493 per million population (95% confidence interval 282 to 801 per million). The prevalence in those born in 1941-60 (733 per million, 269 to 1596 per million) did not differ significantly from those born between 1961 and 1985 (412 per million, 198 to 758 per million) and was similar in both sexes and across the three broad geographical areas sampled. Genetic testing of the positive specimens for the genotype at PRNP codon 129 revealed a high proportion that were valine homozygous compared with the frequency in the normal population, and in stark contrast with confirmed clinical cases of vCJD, all of which were methionine homozygous at PRNP codon 129. CONCLUSIONS This study corroborates previous studies and suggests a high prevalence of infection with abnormal PrP, indicating vCJD carrier status in the population compared with the 177 vCJD cases to date. These findings have important implications for the management of blood and blood products and for the handling of surgical instruments. |
13759726 | The reconstruction of gene regulatory networks underlying cell differentiation from high-throughput gene expression and chromatin data remains a challenge. Here, we derive dynamic gene regulatory networks for human myeloid differentiation using a 5-day time series of RNA-seq and ATAC-seq data. We profile HL-60 promyelocytes differentiating into macrophages, neutrophils, monocytes, and monocyte-derived macrophages. We find a rapid response in the expression of key transcription factors and lineage markers that only regulate a subset of their targets at a given time, which is followed by chromatin accessibility changes that occur later along with further gene expression changes. We observe differences between promyelocyte- and monocyte-derived macrophages at both the transcriptional and chromatin landscape level, despite using the same differentiation stimulus, which suggest that the path taken by cells in the differentiation landscape defines their end cell state. More generally, our approach of combining neighboring time points and replicates to achieve greater sequencing depth can efficiently infer footprint-based regulatory networks from long series data. |
13763195 | Mammalian long intergenic noncoding RNAs (lincRNAs) are best known for modulating transcription. Here we report a posttranscriptional function for lincRNA-p21 as a modulator of translation. Association of the RNA-binding protein HuR with lincRNA-p21 favored the recruitment of let-7/Ago2 to lincRNA-p21, leading to lower lincRNA-p21 stability. Under reduced HuR levels, lincRNA-p21 accumulated in human cervical carcinoma HeLa cells, increasing its association with JUNB and CTNNB1 mRNAs and selectively lowering their translation. With elevated HuR, lincRNA-p21 levels declined, which in turn derepressed JunB and β-catenin translation and increased the levels of these proteins. We propose that HuR controls translation of a subset of target mRNAs by influencing lincRNA-p21 levels. Our findings uncover a role for lincRNA as a posttranscriptional inhibitor of translation. |
13768432 | BACKGROUND The prognosis and treatment of the 2 main types of cardiac amyloidosis, immunoglobulin light chain (AL) and transthyretin (ATTR) amyloidosis, are substantially influenced by cardiac involvement. Cardiovascular magnetic resonance with late gadolinium enhancement (LGE) is a reference standard for the diagnosis of cardiac amyloidosis, but its potential for stratifying risk is unknown. METHODS AND RESULTS Two hundred fifty prospectively recruited subjects, 122 patients with ATTR amyloid, 9 asymptomatic mutation carriers, and 119 patients with AL amyloidosis, underwent LGE cardiovascular magnetic resonance. Subjects were followed up for a mean of 24±13 months. LGE was performed with phase-sensitive inversion recovery (PSIR) and without (magnitude only). These were compared with extracellular volume measured with T1 mapping. PSIR was superior to magnitude-only inversion recovery LGE because PSIR always nulled the tissue (blood or myocardium) with the longest T1 (least gadolinium). LGE was classified into 3 patterns: none, subendocardial, and transmural, which were associated with increasing amyloid burden as defined by extracellular volume (P<0.0001), with transitions from none to subendocardial LGE at an extracellular volume of 0.40 to 0.43 (AL) and 0.39 to 0.40 (ATTR) and to transmural at 0.48 to 0.55 (AL) and 0.47 to 0.59 (ATTR). Sixty-seven patients (27%) died. Transmural LGE predicted death (hazard ratio, 5.4; 95% confidence interval, 2.1-13.7; P<0.0001) and remained independent after adjustment for N-terminal pro-brain natriuretic peptide, ejection fraction, stroke volume index, E/E', and left ventricular mass index (hazard ratio, 4.1; 95% confidence interval, 1.3-13.1; P<0.05). CONCLUSIONS There is a continuum of cardiac involvement in systemic AL and ATTR amyloidosis. Transmural LGE is determined reliably by PSIR and represents advanced cardiac amyloidosis. The PSIR technique provides incremental information on outcome even after adjustment for known prognostic factors. |
13770184 | BACKGROUND The Global Burden of Diseases, Injuries, and Risk Factors Study 2015 provides an up-to-date synthesis of the evidence for risk factor exposure and the attributable burden of disease. By providing national and subnational assessments spanning the past 25 years, this study can inform debates on the importance of addressing risks in context. METHODS We used the comparative risk assessment framework developed for previous iterations of the Global Burden of Disease Study to estimate attributable deaths, disability-adjusted life-years (DALYs), and trends in exposure by age group, sex, year, and geography for 79 behavioural, environmental and occupational, and metabolic risks or clusters of risks from 1990 to 2015. This study included 388 risk-outcome pairs that met World Cancer Research Fund-defined criteria for convincing or probable evidence. We extracted relative risk and exposure estimates from randomised controlled trials, cohorts, pooled cohorts, household surveys, census data, satellite data, and other sources. We used statistical models to pool data, adjust for bias, and incorporate covariates. We developed a metric that allows comparisons of exposure across risk factors-the summary exposure value. Using the counterfactual scenario of theoretical minimum risk level, we estimated the portion of deaths and DALYs that could be attributed to a given risk. We decomposed trends in attributable burden into contributions from population growth, population age structure, risk exposure, and risk-deleted cause-specific DALY rates. We characterised risk exposure in relation to a Socio-demographic Index (SDI). FINDINGS Between 1990 and 2015, global exposure to unsafe sanitation, household air pollution, childhood underweight, childhood stunting, and smoking each decreased by more than 25%. Global exposure for several occupational risks, high body-mass index (BMI), and drug use increased by more than 25% over the same period. All risks jointly evaluated in 2015 accounted for 57·8% (95% CI 56·6-58·8) of global deaths and 41·2% (39·8-42·8) of DALYs. In 2015, the ten largest contributors to global DALYs among Level 3 risks were high systolic blood pressure (211·8 million [192·7 million to 231·1 million] global DALYs), smoking (148·6 million [134·2 million to 163·1 million]), high fasting plasma glucose (143·1 million [125·1 million to 163·5 million]), high BMI (120·1 million [83·8 million to 158·4 million]), childhood undernutrition (113·3 million [103·9 million to 123·4 million]), ambient particulate matter (103·1 million [90·8 million to 115·1 million]), high total cholesterol (88·7 million [74·6 million to 105·7 million]), household air pollution (85·6 million [66·7 million to 106·1 million]), alcohol use (85·0 million [77·2 million to 93·0 million]), and diets high in sodium (83·0 million [49·3 million to 127·5 million]). From 1990 to 2015, attributable DALYs declined for micronutrient deficiencies, childhood undernutrition, unsafe sanitation and water, and household air pollution; reductions in risk-deleted DALY rates rather than reductions in exposure drove these declines. Rising exposure contributed to notable increases in attributable DALYs from high BMI, high fasting plasma glucose, occupational carcinogens, and drug use. Environmental risks and childhood undernutrition declined steadily with SDI; low physical activity, high BMI, and high fasting plasma glucose increased with SDI. In 119 countries, metabolic risks, such as high BMI and fasting plasma glucose, contributed the most attributable DALYs in 2015. Regionally, smoking still ranked among the leading five risk factors for attributable DALYs in 109 countries; childhood underweight and unsafe sex remained primary drivers of early death and disability in much of sub-Saharan Africa. INTERPRETATION Declines in some key environmental risks have contributed to declines in critical infectious diseases. Some risks appear to be invariant to SDI. Increasing risks, including high BMI, high fasting plasma glucose, drug use, and some occupational exposures, contribute to rising burden from some conditions, but also provide opportunities for intervention. Some highly preventable risks, such as smoking, remain major causes of attributable DALYs, even as exposure is declining. Public policy makers need to pay attention to the risks that are increasingly major contributors to global burden. FUNDING Bill & Melinda Gates Foundation. |
13771184 | RecQ helicases are an important family of genome surveillance proteins conserved from bacteria to humans. Each of the five human RecQ helicases plays critical roles in genome maintenance and stability, and the RecQ protein family members are often referred to as guardians of the genome. The importance of these proteins in cellular homeostasis is underscored by the fact that defects in BLM, WRN, and RECQL4 are linked to distinct heritable human disease syndromes. Each human RecQ helicase has a unique set of protein-interacting partners, and these interactions dictate its specialized functions in genome maintenance, including DNA repair, recombination, replication, and transcription. Human RecQ helicases also interact with each other, and these interactions have significant impact on enzyme function. Future research goals in this field include a better understanding of the division of labor among the human RecQ helicases and learning how human RecQ helicases collaborate and cooperate to enhance genome stability. |
13774178 | BACKGROUND Schisandra, a globally distributed plant, has been widely applied for the treatment of diseases such as hyperlipidemia, fatty liver and obesity in China. In the present work, a rapid resolution liquid chromatography coupled with quadruple-time-of-flight mass spectrometry (RRLC-Q-TOF-MS)-based metabolomics was conducted to investigate the intervention effect of Schisandra chinensis lignans (SCL) on hyperlipidemia mice induced by high-fat diet (HFD). METHODS Hyperlipidemia mice were orally administered with SCL (100 mg/kg) once a day for 4 weeks. Serum biochemistry assay of triglyceride (TG), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-c) and high-density lipoprotein cholesterol (HDL-c) was conducted to confirm the treatment of SCL on lipid regulation. Metabolomics analysis on serum samples was carried out, and principal component analysis (PCA) and partial least squares-discriminant analysis (PLS-DA) were carried out for the pattern recognition and characteristic metabolites identification. The relative levels of critical regulatory factors of liver lipid metabolism, sterol regulatory element-binding proteins (SREBPs) and its related gene expressions were measured by quantitative real-time polymerase chain reaction (RT-PCR) for investigating the underlying mechanism. RESULTS Oral administration of SCL significantly decreased the serum levels of TC, TG and LDL-c and increased the serum level of HDL-c in the hyperlipidemia mice, and no effect of SCL on blood lipid levels was observed in control mice. Serum samples were scattered in the PCA scores plots in response to the control, HFD and SCL group. Totally, thirteen biomarkers were identified and nine of them were recovered to the normal levels after SCL treatment. Based on the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways analysis, the anti-hyperlipidemia mechanisms of SCL may be involved in the following metabolic pathways: tricarboxylic acid (TCA) cycle, synthesis of ketone body and cholesterol, choline metabolism and fatty acid metabolism. Meanwhile, SCL significantly inhibited the mRNA expression level of hepatic lipogenesis genes such as SREBP-1c, fatty acid synthase (FAS) and acetyl-CoA carboxylase (ACC), and decreased the mRNA expression of liver X receptor α (LXRα). Moreover, SCL also significantly decreased the expression level of SREBP-2 and 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGCR) in the liver of hyperlipidemia mice. CONCLUSION Anti-hyperlipidemia effect of SCL was confirmed by both serum biochemistry and metabolomics analysis. The mechanism may be related to the down-regulation of LXRα/SREBP-1c/FAS/ACC and SREBP2/HMGCR signaling pathways. |
13778710 | Chemokine-like receptor 1 (CMKLR1), also known as ChemR23, and chemokine (C-C motif) receptor-like 2 (CCRL2) are 7-transmembrane receptors that were cloned in the late 1990s based on their homology to known G-protein-coupled receptors. They were previously orphan receptors without any known biological roles; however, recent studies identified ligands for these receptors and their functions have begun to be unveiled. The plasma protein-derived chemoattractant chemerin is a ligand for CMKLR1 and activation of CMKLR1 with chemerin induces the migration of macrophages and dendritic cells (DCs) in vitro, suggesting a proinflammatory role. However, in vivo studies using CMKLR-deficient mice suggest an anti-inflammatory role for this receptor, possibly due to the recruitment of tolerogenic plasmacytoid DCs. Chemerin/CMKLR1 interaction also promotes adipogenesis and angiogenesis. The anti-inflammatory lipid mediator, resolving E1, is another CMKLR1 ligand and it inhibits leukocyte infiltration and proinflammatory gene expression. These divergent results suggest that CMKLR1 is a multifunctional receptor. The chemokine CCL5 and CCL19 are reported to bind to CCRL2. Like Duffy antigen for chemokine receptor (DARC), D6 and CCX-CKR, CCRL2 does not signal, but it constitutively recycles, potentially reducing local concentration of CCL5 and CCL19 and subsequent immune responses. Surprisingly, chemerin, a ligand for CMKLR1, is a ligand for CCRL2. CCRL2 binds chemerin and increases local chemerin concentration to efficiently present it to CMKLR1 on nearby cells, providing a link between CCRL2 and CMKLR1. Although these findings suggest an anti-inflammatory role, a recent study using CCRL2-deficient mice indicates a proinflammatory role; thus, CCRL2 may also be multifunctional. Further studies using CMKLR1- or CCRL2-deficient mice are needed to further define the role of these receptors in immune responses and other cellular processes. |
13780287 | When cells are activated by calcium-mobilizing agonists at low, physiological concentrations, the resulting calcium signals generally take the form of repetitive regenerative discharges of stored calcium, termed calcium oscillations [1]. These intracellular calcium oscillations have long fascinated biologists as a mode of digitized intracellular signaling. Recent work has highlighted the role of calcium influx as an essential component of calcium oscillations [2]. This influx occurs through a process known as store-operated calcium entry, which is initiated by calcium sensor proteins, STIM1 and STIM2, in the endoplasmic reticulum [3]. STIM2 is activated by changes in endoplasmic reticulum calcium near the resting level, whereas a threshold of calcium depletion is required for STIM1 activation [4]. Here we show that, surprisingly, it is STIM1 and not STIM2 that is exclusively involved in calcium entry during calcium oscillations. The implication is that each oscillation produces a transient drop in endoplasmic reticulum calcium and that this drop is sufficient to transiently activate STIM1. This transient activation of STIM1 can be observed in some cells by total internal reflection fluorescence microscopy. This arrangement nicely provides a clearly defined and unambiguous signaling system, translating a digital calcium release signal into calcium influx that can signal to downstream effectors. |
13782317 | OBJECTIVE This report presents national estimates of the use of complementary health approaches among adults in the United States across three time points. Trends in the use of selected complementary health approaches are compared for 2002, 2007, and 2012, and differences by selected demographic characteristics are also examined. METHODS Combined data from 88,962 adults aged 18 and over collected as part of the 2002, 2007, and 2012 National Health Interview Survey were analyzed for this report. Sample data were weighted to produce national estimates that are representative of the civilian noninstitutionalized U.S. adult population. Differences between percentages were evaluated using two-sided significance tests at the 0.05 level. RESULTS Although the use of individual approaches varied across the three time points, nonvitamin, nonmineral dietary supplements remained the most popular complementary health approach used. The use of yoga, tai chi, and qi gong increased linearly across the three time points; among these three approaches, yoga accounted for approximately 80% of the prevalence. The use of any complementary health approach also differed by selected sociodemographic characteristics. The most notable observed differences in use were by age and Hispanic or Latino origin and race. |
13790144 | Histone proteins play essential structural and functional roles in the transition between active and inactive chromatin states. Although histones have a high degree of conservation due to constraints to maintain the overall structure of the nucleosomal octameric core, variants have evolved to assume diverse roles in gene regulation and epigenetic silencing. Histone variants, post-translational modifications and interactions with chromatin remodeling complexes influence DNA replication, transcription, repair and recombination. The authors review recent findings on the structure of chromatin that confirm previous interparticle interactions observed in crystal structures. |
13791044 | CONTEXT Although preterm delivery is a well-established risk factor for cerebral palsy (CP), preterm deliveries contribute only a minority of affected infants. There is little information on the relation of CP risk to gestational age in the term range, where most CP occurs. OBJECTIVE To determine whether timing of birth in the term and postterm period is associated with risk of CP. DESIGN, SETTING, AND PARTICIPANTS Population-based follow-up study using the Medical Birth Registry of Norway to identify 1,682,441 singleton children born in the years 1967-2001 with a gestational age of 37 through 44 weeks and no congenital anomalies. The cohort was followed up through 2005 by linkage to other national registries. MAIN OUTCOME MEASURES Absolute and relative risk of CP for children surviving to at least 4 years of age. RESULTS Of the cohort of term and postterm children, 1938 were registered with CP in the National Insurance Scheme. Infants born at 40 weeks had the lowest risk of CP, with a prevalence of 0.99/1000 (95% confidence interval [CI], 0.90-1.08). Risk for CP was higher with earlier or later delivery, with a prevalence at 37 weeks of 1.91/1000 (95% CI, 1.58-2.25) and a relative risk (RR) of 1.9 (95% CI, 1.6-2.4), a prevalence at 38 weeks of 1.25/1000 (95% CI, 1.07-1.42) and an RR of 1.3 (95% CI, 1.1-1.6), a prevalence at 42 weeks of 1.36/1000 (95% CI, 1.19-1.53) and an RR of 1.4 (95% CI, 1.2-1.6), and a prevalence after 42 weeks of 1.44 (95% CI, 1.15-1.72) and an RR of 1.4 (95% CI, 1.1-1.8). These associations were even stronger in a subset with gestational age based on ultrasound measurements: at 37 weeks the prevalence was 1.17/1000 (95% CI, 0.30-2.04) and the relative risk was 3.7 (95% CI, 1.5-9.1). At 42 weeks the prevalence was 0.85/1000 (95% CI, 0.33-1.38) and the relative risk was 2.4 (95% CI, 1.1-5.3). Adjustment for infant sex, maternal age, and various socioeconomic measures had little effect. CONCLUSION Compared with delivery at 40 weeks' gestation, delivery at 37 or 38 weeks or at 42 weeks or later was associated with an increased risk of CP. |
13791788 | Mexico harbors great cultural and ethnic diversity, yet fine-scale patterns of human genome-wide variation from this region remain largely uncharacterized. We studied genomic variation within Mexico from over 1000 individuals representing 20 indigenous and 11 mestizo populations. We found striking genetic stratification among indigenous populations within Mexico at varying degrees of geographic isolation. Some groups were as differentiated as Europeans are from East Asians. Pre-Columbian genetic substructure is recapitulated in the indigenous ancestry of admixed mestizo individuals across the country. Furthermore, two independently phenotyped cohorts of Mexicans and Mexican Americans showed a significant association between subcontinental ancestry and lung function. Thus, accounting for fine-scale ancestry patterns is critical for medical and population genetic studies within Mexico, in Mexican-descent populations, and likely in many other populations worldwide. |
13798951 | CD4 T cells play critical roles in mediating adaptive immunity to a variety of pathogens. They are also involved in autoimmunity, asthma, and allergic responses as well as in tumor immunity. During TCR activation in a particular cytokine milieu, naive CD4 T cells may differentiate into one of several lineages of T helper (Th) cells, including Th1, Th2, Th17, and iTreg, as defined by their pattern of cytokine production and function. In this review, we summarize the discovery, functions, and relationships among Th cells; the cytokine and signaling requirements for their development; the networks of transcription factors involved in their differentiation; the epigenetic regulation of their key cytokines and transcription factors; and human diseases involving defective CD4 T cell differentiation. |
13801259 | We have developed a modified version of our fully automated column-switching HPLC method for determining total plasma homocysteine based on single-column (reversed-phase) separation. Homocysteine, cysteine, and cysteinylglycine in plasma (total concentrations), acid-precipitated plasma (non-protein-bound concentrations), and urine can be determined. The derivatization and chromatography were performed automatically by a sample processor. The successful separation of all thiol species (within 15 min) was accomplished by accurate adjustment of the pH of the mobile phase to 3.65 (plasma) or 3.50 (acid-precipitated plasma, urine). Maximal fluorescence yield of cysteine, cysteinylglycine, and, to a lesser degree, homocysteine was dependent on optimal concentrations of EDTA and dithioerythritol during reduction (with NaBH4) and derivatization (with monobromobimane). The method is sensitive (detection limit approximately 0.05 pmol) and has a high degree of precision (CV < 5%). The sample output is approximately 70 samples in 24 h. Serum and heparin plasma can also be analyzed. Hemolysis up to approximately 2.0 g/L of hemoglobin did not interfere with the analytical recovery of homocysteine or cysteine. Collection of blood, separation of plasma from whole blood, and acid precipitation must be standardized to obtain reproducible thiol results. Our modifications and the standardization of blood-sampling procedures have substantially improved the method and broadened its applications. |
13831558 | BACKGROUND Extensive mammographic density is associated with an increased risk of breast cancer and makes the detection of cancer by mammography difficult, but the influence of density on risk according to method of cancer detection is unknown. METHODS We carried out three nested case-control studies in screened populations with 1112 matched case-control pairs. We examined the association of the measured percentage of density in the baseline mammogram with risk of breast cancer, according to method of cancer detection, time since the initiation of screening, and age. RESULTS As compared with women with density in less than 10% of the mammogram, women with density in 75% or more had an increased risk of breast cancer (odds ratio, 4.7; 95% confidence interval [CI], 3.0 to 7.4), whether detected by screening (odds ratio, 3.5; 95% CI, 2.0 to 6.2) or less than 12 months after a negative screening examination (odds ratio, 17.8; 95% CI, 4.8 to 65.9). Increased risk of breast cancer, whether detected by screening or other means, persisted for at least 8 years after study entry and was greater in younger than in older women. For women younger than the median age of 56 years, 26% of all breast cancers and 50% of cancers detected less than 12 months after a negative screening test were attributable to density in 50% or more of the mammogram. CONCLUSIONS Extensive mammographic density is strongly associated with the risk of breast cancer detected by screening or between screening tests. A substantial fraction of breast cancers can be attributed to this risk factor. |
13831842 | The association between anthropometric indices and the risk of breast cancer was analyzed using pooled data from seven prospective cohort studies. Together, these cohorts comprise 337,819 women and 4,385 incident invasive breast cancer cases. In multivariate analyses controlling for reproductive, dietary, and other risk factors, the pooled relative risk (RR) of breast cancer per height increment of 5 cm was 1.02 (95% confidence interval (CI): 0.96, 1.10) in premenopausal women and 1.07 (95% CI: 1.03, 1.12) in postmenopausal women. Body mass index (BMI) showed significant inverse and positive associations with breast cancer among pre- and postmenopausal women, respectively; these associations were nonlinear. Compared with premenopausal women with a BMI of less than 21 kg/m2, women with a BMI exceeding 31 kg/m2 had an RR of 0.54 (95% CI: 0.34, 0.85). In postmenopausal women, the RRs did not increase further when BMI exceeded 28 kg/m2; the RR for these women was 1.26 (95% CI: 1.09, 1.46). The authors found little evidence for interaction with other breast cancer risk factors. Their data indicate that height is an independent risk factor for postmenopausal breast cancer; in premenopausal women, this relation is less clear. The association between BMI and breast cancer varies by menopausal status. Weight control may reduce the risk among postmenopausal women. |
13867350 | The canonical Wnt signaling pathway is of paramount importance in development and disease. An emergent question is whether the upstream cascade of the canonical Wnt pathway has physiologically relevant roles beyond β-catenin-mediated transcription, which is difficult to study due to the pervasive role of this protein. Here, we show that transcriptionally silent spermatozoa respond to Wnt signals released from the epididymis and that mice mutant for the Wnt regulator Cyclin Y-like 1 are male sterile due to immotile and malformed spermatozoa. Post-transcriptional Wnt signaling impacts spermatozoa through GSK3 by (1) reducing global protein poly-ubiquitination to maintain protein homeostasis; (2) inhibiting septin 4 phosphorylation to establish a membrane diffusion barrier in the sperm tail; and (3) inhibiting protein phosphatase 1 to initiate sperm motility. The results indicate that Wnt signaling orchestrates a rich post-transcriptional sperm maturation program and invite revisiting transcription-independent Wnt signaling in somatic cells as well. |
13868795 | Ligation of the CD28 receptor on T cells provides a critical second signal alongside T cell receptor (TCR) ligation for naive T cell activation. Here, we discuss the expression, structure, and biochemistry of CD28 and its ligands. CD28 signals play a key role in many T cell processes, including cytoskeletal remodeling, production of cytokines, survival, and differentiation. CD28 ligation leads to unique epigenetic, transcriptional, and post-translational changes in T cells that cannot be recapitulated by TCR ligation alone. We discuss the function of CD28 and its ligands in both effector and regulatory T cells. CD28 is critical for regulatory T cell survival and the maintenance of immune homeostasis. We outline the roles that CD28 and its family members play in human disease and we review the clinical efficacy of drugs that block CD28 ligands. Despite the centrality of CD28 and its family members and ligands to immune function, many aspects of CD28 biology remain unclear. Translation of a basic understanding of CD28 function into immunomodulatory therapeutics has been uneven, with both successes and failures. Such real-world results might stem from multiple factors, including complex receptor-ligand interactions among CD28 family members, differences between the mouse and human CD28 families, and cell-type specific roles of CD28 family members. |
13870943 | The International Panel on MS Diagnosis presents revised diagnostic criteria for multiple sclerosis (MS). The focus remains on the objective demonstration of dissemination of lesions in both time and space. Magnetic resonance imaging is integrated with dinical and other paraclinical diagnostic methods. The revised criteria facilitate the diagnosis of MS in patients with a variety of presentations, including "monosymptomatic" disease suggestive of MS, disease with a typical relapsing-remitting course, and disease with insidious progression, without clear attacks and remissions. Previously used terms such as "clinically definite" and "probable MS" are no longer recommended. The outcome of a diagnostic evaluation is either MS, "possible MS" (for those at risk for MS, but for whom diagnostic evaluation is equivocal), or "not MS. " |
13878124 | Radial glial cells (RGCs) in the developing cerebral cortex are progenitors for neurons and glia, and their processes serve as guideposts for migrating neurons. So far, it has remained unclear whether RGC processes also control the function of RGCs more directly. Here, we show that RGC numbers and cortical size are reduced in mice lacking beta1 integrins in RGCs. TUNEL stainings and time-lapse video recordings demonstrate that beta1-deficient RGCs processes detach from the meningeal basement membrane (BM) followed by apoptotic death of RGCs. Apoptosis is also induced by surgical removal of the meninges. Finally, mice lacking the BM components laminin alpha2 and alpha4 show defects in the attachment of RGC processes at the meninges, a reduction in cortical size, and enhanced apoptosis of RGC cells. Our findings demonstrate that attachment of RGC processes at the meninges is important for RGC survival and the control of cortical size. |
13878643 | Newly activated CD8(+) T cells reprogram their metabolism to meet the extraordinary biosynthetic demands of clonal expansion; however, the signals that mediate metabolic reprogramming remain poorly defined. Here we demonstrate an essential role for sterol regulatory element-binding proteins (SREBPs) in the acquisition of effector-cell metabolism. Without SREBP signaling, CD8(+) T cells were unable to blast, which resulted in attenuated clonal expansion during viral infection. Mechanistic studies indicated that SREBPs were essential for meeting the heightened lipid requirements of membrane synthesis during blastogenesis. SREBPs were dispensable for homeostatic proliferation, which indicated a context-specific requirement for SREBPs in effector responses. Our studies provide insights into the molecular signals that underlie the metabolic reprogramming of CD8(+) T cells during the transition from quiescence to activation. |
13883546 | The term antidepressant refers to a drug that helps to rectify specific biological abnormalities that give rise to the symptoms of depression. This exemplifies what we have called the “disease-centred” model of psychotropic drug action [ 1]. Modelled on paradigmatic situations in general medicine—such as the use of insulin in diabetes, antibiotics in infectious disease, chemotherapy in cancer—the disease-centred model suggests that antidepressants help restore normal functioning by acting on the neuropathology of depression or of depressive symptoms. In contrast, we propose in this Essay that an alternative “drug-centred” model can better explain observed drug effects in psychiatric conditions. This drug-centred model suggests that instead of relieving a hypothetical biochemical abnormality, drugs themselves cause abnormal states, which may coincidentally relieve psychiatric symptoms ( Table 1). Alcohol's disinhibiting effects may relieve symptoms of social phobia, but that does not imply that alcohol corrects a chemical imbalance underlying social phobia. Sedation may lessen high arousal, present in many acute psychiatric situations. Drugs that induce indifference, such as neuroleptics or opiates, may help reduce the distress of acute psychotic symptoms. Low-dose stimulants may help improve attention and concentration in the short term. Table 1 Main Assumptions of Two Models of Psychotropic Drug Action The disease-centred model in psychiatry leads researchers to infer antidepressant effects from patients' scores on symptom rating scales presumed to assess the manifestations of the disease. The drug-centred model, on the other hand, suggests that physiological and subjective effects of drugs should be examined in their own right. These effects include various forms of sedation, stimulation, and a plethora of biopsychological states. Depending on individual inclination and context (including a person's emotional state upon drug ingestion), intoxication with some drugs produces euphoria or mood elevation. Because tolerance develops, however, euphoriant effects do not persist with long-term use. If antidepressants or any other psychotropic drugs could be shown to have mood-elevating effects that were long-term and not diminished by being in a depressed emotional state, this would distinguish them from psychotropic drugs that cause euphoria and might prove uniquely useful in depressed patients (see Sidebar). |
13889430 | There is a growing interest in the cell-cell communication roles in cancer mediated by secreted vesicles termed exosomes. In this study, we examined whether exosomes produced by cancer cells could transmit information to normal stromal fibroblasts and trigger a cellular response. We found that some cancer-derived exosomes could trigger elevated α-smooth muscle actin expression and other changes consistent with the process of fibroblast differentiation into myofibroblasts. We show that TGF-β is expressed at the exosome surface in association with the transmembrane proteoglycan betaglycan. Although existing in a latent state, this complex was fully functional in eliciting SMAD-dependent signaling. Inhibiting either signaling or betaglycan expression attenuated differentiation. While the kinetics and overall magnitude of the response were similar to that achieved with soluble TGF-β, we identified important qualitative differences unique to the exosomal route of TGF-β delivery, as exemplified by a significant elevation in fibroblast FGF2 production. This hitherto unknown trigger for instigating cellular differentiation in a distinctive manner has major implications for mechanisms underlying cancer-recruited stroma, fibrotic diseases, and wound-healing responses. |
13899137 | BACKGROUND Many mathematical models have investigated the impact of expanding access to antiretroviral therapy (ART) on new HIV infections. Comparing results and conclusions across models is challenging because models have addressed slightly different questions and have reported different outcome metrics. This study compares the predictions of several mathematical models simulating the same ART intervention programmes to determine the extent to which models agree about the epidemiological impact of expanded ART. METHODS AND FINDINGS Twelve independent mathematical models evaluated a set of standardised ART intervention scenarios in South Africa and reported a common set of outputs. Intervention scenarios systematically varied the CD4 count threshold for treatment eligibility, access to treatment, and programme retention. For a scenario in which 80% of HIV-infected individuals start treatment on average 1 y after their CD4 count drops below 350 cells/µl and 85% remain on treatment after 3 y, the models projected that HIV incidence would be 35% to 54% lower 8 y after the introduction of ART, compared to a counterfactual scenario in which there is no ART. More variation existed in the estimated long-term (38 y) reductions in incidence. The impact of optimistic interventions including immediate ART initiation varied widely across models, maintaining substantial uncertainty about the theoretical prospect for elimination of HIV from the population using ART alone over the next four decades. The number of person-years of ART per infection averted over 8 y ranged between 5.8 and 18.7. Considering the actual scale-up of ART in South Africa, seven models estimated that current HIV incidence is 17% to 32% lower than it would have been in the absence of ART. Differences between model assumptions about CD4 decline and HIV transmissibility over the course of infection explained only a modest amount of the variation in model results. CONCLUSIONS Mathematical models evaluating the impact of ART vary substantially in structure, complexity, and parameter choices, but all suggest that ART, at high levels of access and with high adherence, has the potential to substantially reduce new HIV infections. There was broad agreement regarding the short-term epidemiologic impact of ambitious treatment scale-up, but more variation in longer term projections and in the efficiency with which treatment can reduce new infections. Differences between model predictions could not be explained by differences in model structure or parameterization that were hypothesized to affect intervention impact. |
13901073 | BACKGROUND Expanded access to antiretroviral therapy (ART) using universal test and treat (UTT) has been suggested as a strategy to eliminate HIV in South Africa within 7 y based on an influential mathematical modeling study. However, the underlying deterministic model was criticized widely, and other modeling studies did not always confirm the study's finding. The objective of our study is to better understand the implications of different model structures and assumptions, so as to arrive at the best possible predictions of the long-term impact of UTT and the possibility of elimination of HIV. METHODS AND FINDINGS We developed nine structurally different mathematical models of the South African HIV epidemic in a stepwise approach of increasing complexity and realism. The simplest model resembles the initial deterministic model, while the most comprehensive model is the stochastic microsimulation model STDSIM, which includes sexual networks and HIV stages with different degrees of infectiousness. We defined UTT as annual screening and immediate ART for all HIV-infected adults, starting at 13% in January 2012 and scaled up to 90% coverage by January 2019. All models predict elimination, yet those that capture more processes underlying the HIV transmission dynamics predict elimination at a later point in time, after 20 to 25 y. Importantly, the most comprehensive model predicts that the current strategy of ART at CD4 count ≤350 cells/µl will also lead to elimination, albeit 10 y later compared to UTT. Still, UTT remains cost-effective, as many additional life-years would be saved. The study's major limitations are that elimination was defined as incidence below 1/1,000 person-years rather than 0% prevalence, and drug resistance was not modeled. CONCLUSIONS Our results confirm previous predictions that the HIV epidemic in South Africa can be eliminated through universal testing and immediate treatment at 90% coverage. However, more realistic models show that elimination is likely to occur at a much later point in time than the initial model suggested. Also, UTT is a cost-effective intervention, but less cost-effective than previously predicted because the current South African ART treatment policy alone could already drive HIV into elimination. Please see later in the article for the Editors' Summary. |
13902570 | OBJECTIVE TGR5 is a G-protein-coupled receptor for bile acids. So far, little is known about the function of TGR5 in vascular endothelial cells. APPROACH AND RESULTS In bovine aortic endothelial cells, treatment with a bile acid having a high affinity to TGR5, taurolithocholic acid (TLCA), significantly increased NO production. This effect was abolished by small interfering RNA-mediated depletion of TGR5. TLCA-induced NO production was also observed in human umbilical vein endothelial cells measured via intracellular cGMP accumulation. TLCA increased endothelial NO synthase(ser1177) phosphorylation in human umbilical vein endothelial cells. This response was accompanied by increased Akt(ser473) phosphorylation and intracellular Ca(2+). Inhibition of these signals significantly decreased TLCA-induced NO production. We next examined whether TGR5-mediated NO production affects inflammatory responses of endothelial cells. In human umbilical vein endothelial cells, TLCA significantly reduced tumor necrosis factor-α-induced adhesion of monocytes, vascular cell adhesion molecule-1 expression, and activation of nuclear factor-κB. TLCA also inhibited lipopolysaccharide-induced monocyte adhesion to mesenteric venules in vivo. These inhibitory effects of TLCA were abrogated by NO synthase inhibition. CONCLUSIONS TGR5 agonism induces NO production via Akt activation and intracellular Ca(2+) increase in vascular endothelial cells, and this function inhibits monocyte adhesion in response to inflammatory stimuli. |