title: Pain attacks in non-complicated and complicated gallstone disease have a characteristic pattern and are accompanied by dyspepsia in most patients: the results of a prospective study.

text: 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.


title: Prevalence and cardiovascular disease correlates of low cardiorespiratory fitness in adolescents and adults.

text: 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.


title: In situ regulation of DC subsets and T cells mediates tumor regression in mice.

text: Vaccines are largely ineffective for patients with established cancer, as advanced disease requires potent and sustained activation of CD8(+) cytotoxic T lymphocytes (CTLs) to kill tumor cells and clear the disease. Recent studies have found that subsets of dendritic cells (DCs) specialize in antigen cross-presentation and in the production of cytokines, which regulate both CTLs and T regulatory (Treg) cells that shut down effector T cell responses. Here, we addressed the hypothesis that coordinated regulation of a DC network, and plasmacytoid DCs (pDCs) and CD8(+) DCs in particular, could enhance host immunity in mice. We used functionalized biomaterials incorporating various combinations of an inflammatory cytokine, immune danger signal, and tumor lysates to control the activation and localization of host DC populations in situ. The numbers of pDCs and CD8(+) DCs, and the endogenous production of interleukin-12, all correlated strongly with the magnitude of protective antitumor immunity and the generation of potent CD8(+) CTLs. Vaccination by this method maintained local and systemic CTL responses for extended periods while inhibiting FoxP3 Treg activity during antigen clearance, resulting in complete regression of distant and established melanoma tumors. The efficacy of this vaccine as a monotherapy against large invasive tumors may be a result of the local activity of pDCs and CD8(+) DCs induced by persistent danger and antigen signaling at the vaccine site. These results indicate that a critical pattern of DC subsets correlates with the evolution of therapeutic antitumor responses and provide a template for future vaccine design.


title: VEGF inhibits tumor cell invasion and mesenchymal transition through a MET/VEGFR2 complex.

text: Inhibition of VEGF signaling leads to a proinvasive phenotype in mouse models of glioblastoma multiforme (GBM) and in a subset of GBM patients treated with bevacizumab. Here, we demonstrate that vascular endothelial growth factor (VEGF) directly and negatively regulates tumor cell invasion through enhanced recruitment of the protein tyrosine phosphatase 1B (PTP1B) to a MET/VEGFR2 heterocomplex, thereby suppressing HGF-dependent MET phosphorylation and tumor cell migration. Consequently, VEGF blockade restores and increases MET activity in GBM cells in a hypoxia-independent manner, while inducing a program reminiscent of epithelial-to-mesenchymal transition highlighted by a T-cadherin to N-cadherin switch and enhanced mesenchymal features. Inhibition of MET in GBM mouse models blocks mesenchymal transition and invasion provoked by VEGF ablation, resulting in substantial survival benefit.


title: Interaction between Oct3/4 and Cdx2 Determines Trophectoderm Differentiation

text: 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.


title: SSEA-1 is an enrichment marker for tumor-initiating cells in human glioblastoma.

text: 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.


title: Temporal regulation of topoisomerase IV activity in E. coli.

text: We isolated a mutant allele of dnaX, encoding the tau and gamma subunits of the DNA polymerase III holoenzyme, that causes extreme cell filamentation but does not affect either cell growth or DNA replication. This phenotype results from a defect in daughter chromosome decatenation during rapid growth. In these cells, ParC, one subunit of topoisomerase IV, no longer associated with the replication factory, as occurs in wild-type cells, and was instead distributed uniformly on the nucleoid; the distribution of ParE, the other subunit of topoisomerase IV, was unaffected. In addition, the majority of topoisomerase IV activity in synchronized cell populations was restricted to late in the cell cycle, when replication was essentially complete. These observations suggest that topoisomerase IV activity in vivo might be dependent on release of ParC from the replication factory.


title: Molecularly targeted therapy based on tumour molecular profiling versus conventional therapy for advanced cancer (SHIVA): a multicentre, open-label, proof-of-concept, randomised, controlled phase 2 trial.

text: 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.


title: CRTC2 (TORC2) contributes to the transcriptional response to fasting in the liver but is not required for the maintenance of glucose homeostasis.

text: The liver contributes to glucose homeostasis by promoting either storage or production of glucose, depending on the physiological state. The cAMP response element-binding protein (CREB) is a principal regulator of genes involved in coordinating the hepatic response to fasting, but its mechanism of gene activation remains controversial. We derived CRTC2 (CREB-regulated transcription coactivator 2, previously TORC2)-deficient mice to assess the contribution of this cofactor to hepatic glucose metabolism in vivo. CRTC2 mutant hepatocytes showed reduced glucose production in response to glucagon, which correlated with decreased CREB binding to several gluconeogenic genes. However, despite attenuated expression of CREB target genes, including PEPCK, G6Pase, and PGC-1alpha, no hypoglycemia was observed in mutant mice. Collectively, these results provide genetic evidence supporting a role for CRTC2 in the transcriptional response to fasting, but indicate only a limited contribution of this cofactor to the maintenance of glucose homeostasis.


title: Ancient Hybridization and an Irish Origin for the Modern Polar Bear Matriline

text: BACKGROUND Polar bears (Ursus maritimus) are among those species most susceptible to the rapidly changing arctic climate, and their survival is of global concern. Despite this, little is known about polar bear species history. Future conservation strategies would significantly benefit from an understanding of basic evolutionary information, such as the timing and conditions of their initial divergence from brown bears (U. arctos) or their response to previous environmental change. RESULTS We used a spatially explicit phylogeographic model to estimate the dynamics of 242 brown bear and polar bear matrilines sampled throughout the last 120,000 years and across their present and past geographic ranges. Our results show that the present distribution of these matrilines was shaped by a combination of regional stability and rapid, long-distance dispersal from ice-age refugia. In addition, hybridization between polar bears and brown bears may have occurred multiple times throughout the Late Pleistocene. CONCLUSIONS The reconstructed matrilineal history of brown and polar bears has two striking features. First, it is punctuated by dramatic and discrete climate-driven dispersal events. Second, opportunistic mating between these two species as their ranges overlapped has left a strong genetic imprint. In particular, a likely genetic exchange with extinct Irish brown bears forms the origin of the modern polar bear matriline. This suggests that interspecific hybridization not only may be more common than previously considered but may be a mechanism by which species deal with marginal habitats during periods of environmental deterioration.


title: FBW7 ubiquitin ligase: a tumour suppressor at the crossroads of cell division, growth and differentiation

text: FBW7 (F-box and WD repeat domain-containing 7) is the substrate recognition component of an evolutionary conserved SCF (complex of SKP1, CUL1 and F-box protein)-type ubiquitin ligase. SCFFBW7 degrades several proto-oncogenes that function in cellular growth and division pathways, including MYC, cyclin E, Notch and JUN. FBW7 is also a tumour suppressor, the regulatory network of which is perturbed in many human malignancies. Numerous cancer-associated mutations in FBW7 and its substrates have been identified, and loss of FBW7 function causes chromosomal instability and tumorigenesis. This Review focuses on structural and functional aspects of FBW7 and its role in the development of cancer.


title: Hypoglycemic episodes and risk of dementia in older patients with type 2 diabetes mellitus.

text: 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.


title: Defective mast cell effector functions in mice lacking the CRACM1 pore subunit of store-operated calcium release–activated calcium channels

text: 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.


title: MicroRNA-7: A miRNA with expanding roles in development and disease.

text: 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.


title: Integration-free induced pluripotent stem cells model genetic and neural developmental features of down syndrome etiology.

text: 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.


title: In Vivo CRISPR/Cas9 Gene Editing Corrects Retinal Dystrophy in the S334ter-3 Rat Model of Autosomal Dominant Retinitis Pigmentosa

text: Reliable genome editing via Clustered Regularly Interspaced Short Palindromic Repeat (CRISPR)/Cas9 may provide a means to correct inherited diseases in patients. As proof of principle, we show that CRISPR/Cas9 can be used in vivo to selectively ablate the rhodopsin gene carrying the dominant S334ter mutation (Rho(S334)) in rats that model severe autosomal dominant retinitis pigmentosa. A single subretinal injection of guide RNA/Cas9 plasmid in combination with electroporation generated allele-specific disruption of Rho(S334), which prevented retinal degeneration and improved visual function.


title: Vitamin D insufficiency and the blunted PTH response in established osteoporosis: the role of magnesium deficiency

text: Vitamin D insufficiency is common, however within individuals, not all manifest the biochemical effects of PTH excess. This further extends to patients with established osteoporosis. The mechanism underlying the blunted PTH response is unclear but may be related to magnesium (Mg) deficiency. The aims of this study were to compare in patients with established osteoporosis and differing degrees of vitamin D and PTH status : (1) the presence of Mg deficiency using the standard Mg loading test (2) evaluate the effects of Mg loading on the calcium-PTH endocrine axis (3) determine the effects of oral, short term Mg supplementation on the calcium-PTH endocrine axis and bone turnover. 30 patients (10 women in 3 groups) were evaluated prospectively measuring calcium, PTH, Mg retention (Mg loading test), dietary nutrient intake (calcium, vitamin D, Mg) and bone turnover markers (serum CTX & P1CP). Multivariate analysis controlling for potential confounding baseline variable was undertaken for the measured outcomes. All subjects, within the low vitamin D and low PTH group following the magnesium loading test had evidence of Mg depletion [mean(SD) retention 70.3%(12.5)] and showed an increase in calcium 0.06(0.01) mmol/l [95% CI 0.03, 0.09, p=0.007], together with a rise in PTH 13.3 ng/l (4.5) [95% CI 3.2, 23.4, p=0.016] compared to baseline. Following oral supplementation bone turnover increased: CTX 0.16 (0.06) mcg/l [95%CI 0.01, 0.32 p=0.047]; P1CP 13.1 (5.7) mcg/l [95% CI 0.29, 26.6 p=0.049]. In subjects with a low vitamin D and raised PTH mean retention was 55.9%(14.8) and in the vitamin replete group 36.1%(14.4), with little change in both acute markers of calcium homeostasis and bone turnover markers following both the loading test and oral supplementation. This study confirms that in patients with established osteoporosis, there is also a distinct group with a low vitamin D and a blunted PTH level and that Mg deficiency (as measured by the Mg loading test) is an important contributing factor.


title: Novel syndromes associated with JC virus infection of neurons and meningeal cells: no longer a gray area.

text: 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.


title: Phosphoinositide 3-kinase signalling pathways in tumor progression, invasion and angiogenesis.

text: 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.


title: Complementary foods for infant feeding in developing countries: their nutrient adequacy and improvement

text: Objective: To assess the energy and nutrient adequacy of a variety of complementary foods used in parts of Africa, India, Papua New Guinea, the Philippines and Thailand. Method: The energy, nutrient and anti-nutrient (dietary fibre and phytic acid) content (per 100 g as eaten, per 100 kcal, and per day) of twenty-three plant-based complementary foods consumed in developing countries was calculated from food composition values based on chemical analysis for the trace minerals, non-starch polysaccharide and phytic acid, and the literature. Results were compared with the estimated nutrient needs (per day; per 100 kcal) from complementary foods for infants 9–11 months, assuming a breast milk intake of average volume and composition and three complementary feedings per day, each of 250 g. Results: Complementary foods should provide approximately 25–50% of total daily requirements for protein, riboflavin and copper; 50–75% for thiamin, calcium and manganese; and 75–100% for phosphorus, zinc and iron. Most or all appear to meet the estimated daily nutrient needs (per day; per 100 kcal) from complementary foods for protein, thiamin and copper (per day), but not for calcium, iron, and in some cases zinc, even if moderate bioavailability for iron and zinc is assumed. Some of those based on rice are also inadequate in riboflavin (per day; per 100 kcal).Conclusions: Even if strategies to improve the bioavailability of iron and zinc are employed, they are probably insufficient to overcome the deficits in calcium, iron and zinc. Therefore, research on the feasibility of fortifying plant-based complementary foods in developing countries with calcium, iron and zinc is urgently required. Sponsorship: This study was supported by the Micronutrient Initiative through the Canadian International Development Agency.


title: Early aging and age-related pathologies in mice deficient in BMAL1, the core componentof the circadian clock.

text: 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.


title: A self-inactivating lentiviral vector for SCID-X1 gene therapy that does not activate LMO2 expression in human T cells.

text: 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.


title: Genetic Variants at Newly Identified Lipid Loci Are Associated with Coronary Heart Disease in a Chinese Han Population

text: 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.


title: Spare respiratory capacity rather than oxidative stress regulates glutamate excitotoxicity after partial respiratory inhibition of mitochondrial complex I with rotenone.

text: 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.


title: Isolated liver perfusion for non-resectable liver tumours: a review.

text: 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.


title: Combinatorial control of exon recognition.

text: Pre-mRNA splicing is a fundamental process required for the expression of most metazoan genes. It is carried out by the spliceosome, which catalyzes the removal of noncoding intronic sequences to assemble exons into mature mRNAs prior to export and translation. Given the complexity of higher eukaryotic genes and the relatively low level of splice site conservation, the precision of the splicing machinery in recognizing and pairing splice sites is impressive. Introns ranging in size from <100 up to 100,000 bases are removed efficiently. At the same time, a large number of alternative splicing events are observed between different cell types, during development, or during other biological processes. This extensive alternative splicing implies a significant flexibility of the spliceosome to identify and process exons within a given pre-mRNA. To reach this flexibility, splice site selection in higher eukaryotes has evolved to depend on multiple parameters such as splice site strength, the presence or absence of splicing regulators, RNA secondary structures, the exon/intron architecture, and the process of pre-mRNA synthesis itself. The relative contributions of each of these parameters control how efficiently splice sites are recognized and flanking introns are removed.


title: High CTLA-4 expression on Th17 cells results in increased sensitivity to CTLA-4 coinhibition and resistance to belatacept.

text: 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.


title: A small molecule modulates Jumonji histone demethylase activity and selectively inhibits cancer growth

text: The pharmacological inhibition of general transcriptional regulators has the potential to block growth through targeting multiple tumorigenic signalling pathways simultaneously. Here, using an innovative cell-based screen, we identify a structurally unique small molecule (named JIB-04) that specifically inhibits the activity of the Jumonji family of histone demethylases in vitro, in cancer cells, and in tumours in vivo. Unlike known inhibitors, JIB-04 is not a competitive inhibitor of α-ketoglutarate. In cancer, but not in patient-matched normal cells, JIB-04 alters a subset of transcriptional pathways and blocks viability. In mice, JIB-04 reduces tumour burden and prolongs survival. Importantly, we find that patients with breast tumours that overexpress Jumonji demethylases have significantly lower survival. Thus, JIB-04, a novel inhibitor of Jumonji demethylases in vitro and in vivo, constitutes a unique potential therapeutic and research tool against cancer, and validates the use of unbiased cellular screens to discover chemical modulators with disease relevance.


title: Gq protein alpha subunits Galphaq and Galpha11 are localized at postsynaptic extra-junctional membrane of cerebellar Purkinje cells and hippocampal pyramidal cells.

text: Following cell surface receptor activation, the alpha subunit of the Gq subclass of GTP-binding proteins activates the phosphoinositide signalling pathway. Here we examined the expression and localization of Gq protein alpha subunits in the adult mouse brain by in situ hybridization and immunohistochemistry. Of the four members of the Gq protein alpha subunits, Galphaq and Galpha11 were transcribed predominantly in the brain. The highest transcriptional level of Galphaq was observed in cerebellar Purkinje cells (PCs) and hippocampal pyramidal cells, while that of Galpha11 was noted in hippocampal pyramidal cells. Antibody against the C-terminal peptide common to Galphaq and Galpha11 strongly labelled the cerebellar molecular layer and hippocampal neuropil layers. In these regions, immunogold preferentially labelled the cytoplasmic face of postsynaptic cell membrane of PCs and pyramidal cells. Immunoparticles were distributed along the extra-junctional cell membrane of spines, dendrites and somata, but were almost excluded from the junctional membrane. By double immunofluorescence, Galphaq/Galpha11 was extensively colocalized with metabotropic glutamate receptor mGluR1alpha in dendritic spines of PCs and with mGluR5 in those of hippocampal pyramidal cells. Together with concentrated localization of mGluR1alpha and mGluR5 in a peri-junctional annulus on PC and pyramidal cell synapses (Baude et al. 1993, Neuron, 11, 771-787; Luján et al. 1996, Eur. J. Neurosci., 8, 1488-1500), the present molecular-anatomical findings suggest that peri-junctional stimulation of the group I metabotropic glutamate receptors is mediated by Galphaq and/or Galpha11, leading to the activation of the intracellular effector, phospholipase Cbeta.


title: The Bloom's syndrome gene product is homologous to RecQ helicases

text: The Bloom's syndrome (BS) gene, BLM, plays an important role in the maintenance of genomic stability in somatic cells. A candidate for BLM was identified by direct selection of a cDNA derived from a 250 kb segment of the genome to which BLM had been assigned by somatic crossover point mapping. In this novel mapping method, cells were used from persons with BS that had undergone intragenic recombination within BLM. cDNA analysis of the candidate gene identified a 4437 bp cDNA that encodes a 1417 amino acid peptide with homology to the RecQ helicases, a subfamily of DExH box-containing DNA and RNA helicases. The presence of chain-terminating mutations in the candidate gene in persons with BS proved that it was BLM.


title: Preventing obesity in children and adolescents.

text: In this review, we address the natural history of obesity in children, the most promising family- and school-based approaches to the prevention of obesity, and the barriers and opportunities associated with secondary prevention. In childhood, the most important periods of risk appear to be the periods of adiposity rebound and adolescence. Caution regarding the period of adiposity rebound is still warranted, because it is not yet clear that early rebound is attributable to changes in body fat. Families and schools represent the most important foci for preventive efforts in children and adolescents. One productive approach is to proceed from an examination of factors that affect energy balance to the identification of more proximal influences on those factors. This approach may help to narrow the strategies necessary to prevent or treat childhood obesity. For example, television viewing affects both energy intake and energy expenditure, and therefore represents a logical target for interventions. Anticipatory guidance by pediatricians may offer an effective mechanism by which to change parental attitudes and practices regarding television viewing. A similar process is used to emphasize the potential influence of school-based interventions directed at changes in food choices and sedentary behavior.


title: Culture of Preimplantation Mouse Embryos Affects Fetal Development and the Expression of Imprinted Genes1

text: Abstract Culture of preimplantation mammalian embryos and cells can influence their subsequent growth and differentiation. Previously, we reported that culture of mouse embryonic stem cells is associated with deregulation of genomic imprinting and affects the potential for these cells to develop into normal fetuses. The purpose of our current study was to determine whether culture of preimplantation mouse embryos in a chemically defined medium (M16) with or without fetal calf serum (FCS) can affect their subsequent development and imprinted gene expression. Only one third of the blastocysts that had been cultured from two-cell embryos in M16 medium complemented with FCS developed into viable Day 14 fetuses after transfer into recipients. These M16 + FCS fetuses were reduced in weight as compared with controls and M16 fetuses and had decreased expression of the imprinted H19 and insulin-like growth factor 2 genes associated with a gain of DNA methylation at an imprinting control region upstream of H19. They also displayed increased expression of the imprinted gene Grb10. The growth factor receptor binding gene Grb7, in contrast, was strongly reduced in its expression in most of the M16 + FCS fetuses. No alterations were detected for the imprinted gene Mest. Preimplantation culture in the presence of serum can influence the regulation of multiple growth-related imprinted genes, thus leading to aberrant fetal growth and development.


title: Results of screening for intracranial aneurysms in patients with coarctation of the aorta.

text: 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.


title: A new look at the heart in diabetes mellitus: from ailing to failing

text: 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]


title: Genetic and epigenetic mutations affect the DNA binding capability of human ZFP57 in transient neonatal diabetes type 1

text: In the mouse, ZFP57 contains three classical Cys2His2 zinc finger domains (ZF) and recognizes the methylated TGC(met)CGC target sequence using the first and the second ZFs. In this study, we demonstrate that the human ZFP57 (hZFP57) containing six Cys2His2 ZFs, binds the same methylated sequence through the third and the fourth ZFs, and identify the aminoacids critical for DNA interaction. In addition, we present evidences indicating that hZFP57 mutations and hypomethylation of the TNDM1 ICR both associated with Transient Neonatal Diabetes Mellitus type 1 result in loss of hZFP57 binding to the TNDM1 locus, likely causing PLAGL1 activation.


title: Physiological astrocytic calcium levels stimulate glutamate release to modulate adjacent neurons.

text: Astrocytes can release glutamate in a calcium-dependent manner and consequently signal to adjacent neurons. Whether this glutamate release pathway is used during physiological signaling or is recruited only under pathophysiological conditions is not well defined. One reason for this lack of understanding is the limited knowledge about the levels of calcium necessary to stimulate glutamate release from astrocytes and about how they compare with the range of physiological calcium levels in these cells. We used flash photolysis to raise internal calcium in astrocytes, while monitoring astrocytic calcium levels and glutamate, which evoked slow inward currents that were recorded electrophysiologically from single neurons grown on microislands of astrocytes. With this approach, we demonstrate that modest changes of astrocytic calcium, from 84 to 140 nM, evoke substantial glutamatergic currents in neighboring neurons (-391 pA), with a Hill coefficient of 2.1 to 2.7. Because the agonists glutamate, norepinephrine, and dopamine all raise calcium in astrocytes to levels exceeding 1.8 microM, these quantitative studies demonstrate that the astrocytic glutamate release pathway is engaged at physiological levels of internal calcium. Consequently, the calcium-dependent release of glutamate from astrocytes functions within an appropriate range of astrocytic calcium levels to be used as a signaling pathway within the functional nervous system.


title: Albumin and furosemide therapy in hypoproteinemic patients with acute lung injury.

text: OBJECTIVE Hypoproteinemia, fluid retention, and weight gain are associated with development of acute lung injury and mortality in critically ill patients, without proof of cause and effect. We designed a clinical trial to determine whether diuresis and colloid replacement in hypoproteinemic patients with acute lung injury would improve pulmonary physiology. DESIGN Prospective, randomized, double-blind, placebo-controlled trial. SETTING All adult intensive care units from two university hospitals. PATIENTS Thirty-seven mechanically-ventilated patients with acute lung injury and serum total protein </=5.0 g/dL.   INTERVENTIONS Five-day protocolized regimen of 25 g of human serum albumin every 8 hrs with continuous infusion furosemide, or dual placebo, targeted to diuresis, weight loss, and serum total protein. MEASUREMENTS AND MAIN RESULTS Measured outcomes included change in weight, serum total protein, fluid balance, hemodynamics, respiratory system compliance, and oxygenation. Baseline characteristics were similar between groups (treatment, n = 19; control, n = 18), with trauma being the major cause of acute lung injury. Diuresis and weight loss over 5 days (5.3 kg more in the treatment group, p =.04) was accompanied by improvements in the Pao2/Fio2 ratio in the treatment group within 24 hrs (from 171 to 236, p =.02). Respiratory mechanics were unchanged. Mean arterial pressure increased from 80 to 88 mm Hg (p =.10), and heart rate decreased from 110 to 95 beats/min (p =.008) over time in the treatment group. No difference in mortality was observed, with favorable trends in measures of intensive care. CONCLUSIONS Albumin and furosemide therapy improves fluid balance, oxygenation, and hemodynamics in hypoproteinemic patients with acute lung injury. Determining the effect of this simple therapy on cost, outcomes, and other patient populations requires further study.


title: Advances in functional and structural mr image analysis and implementation as fsl

text: The techniques available for the interrogation and analysis of neuroimaging data have a large influence in determining the flexibility, sensitivity, and scope of neuroimaging experiments. The development of such methodologies has allowed investigators to address scientific questions that could not previously be answered and, as such, has become an important research area in its own right. In this paper, we present a review of the research carried out by the Analysis Group at the Oxford Centre for Functional MRI of the Brain (FMRIB). This research has focussed on the development of new methodologies for the analysis of both structural and functional magnetic resonance imaging data. The majority of the research laid out in this paper has been implemented as freely available software tools within FMRIB's Software Library (FSL).


title: Metformin—mode of action and clinical implications for diabetes and cancer

text: 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.


title: Characteristics of the Earliest Cross-Neutralizing Antibody Response to HIV-1

text: Recent cross-sectional analyses of HIV-1+ plasmas have indicated that broadly cross-reactive neutralizing antibody responses are developed by 10%-30% of HIV-1+ subjects. The timing of the initial development of such anti-viral responses is unknown. It is also unknown whether the emergence of these responses coincides with the appearance of antibody specificities to a single or multiple regions of the viral envelope glycoprotein (Env). Here we analyzed the cross-neutralizing antibody responses in longitudinal plasmas collected soon after and up to seven years after HIV-1 infection. We find that anti-HIV-1 cross-neutralizing antibody responses first become evident on average at 2.5 years and, in rare cases, as early as 1 year following infection. If cross-neutralizing antibody responses do not develop during the first 2-3 years of infection, they most likely will not do so subsequently. Our results indicate a potential link between the development of cross-neutralizing antibody responses and specific activation markers on T cells, and with plasma viremia levels. The earliest cross-neutralizing antibody response targets a limited number of Env regions, primarily the CD4-binding site and epitopes that are not present on monomeric Env, but on the virion-associated trimeric Env form. In contrast, the neutralizing activities of plasmas from subjects that did not develop cross-neutralizing antibody responses target epitopes on monomeric gp120 other than the CD4-BS. Our study provides information that is not only relevant to better understanding the interaction of the human immune system with HIV but may guide the development of effective immunization protocols. Since antibodies to complex epitopes that are present on the virion-associated envelope spike appear to be key components of earliest cross-neutralizing activities of HIV-1+ plasmas, then emphasis should be made to elicit similar antibodies by vaccination.


title: Gender, age, and heart failure with preserved left ventricular systolic function.

text: 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.


title: YAP/TAZ-Dependent Reprogramming of Colonic Epithelium Links ECM Remodeling to Tissue Regeneration

text: 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.


title: Summary

text: Glomerular basement membrane (GBM) and podocalyxin are essential for podocyte morphology. We provide evidence of functional interconnections between basement membrane components (collagen IV and laminin), the expression of podocalyxin and the morphology of human glomerular epithelial cells (podocytes). We demonstrated that GBM and laminin, but not collagen IV, up-regulated the expression of podocalyxin. Scanning electron microscopy revealed that laminin induced a modified morphology of podocytes with process formation, which was more extensive in the presence of GBM. Under high magnification, podocytes appeared ruffled. Using transmission electron microscopy we observed that raised areas occurred in the basal cell surface. Furthermore, the presence of anti-podocalyxin antibody increased the extent of adhesion and spreading of podocytes to both collagen IV and laminin, thus podocalyxin apparently inhibits cell-matrix interactions. We also performed adhesion and spreading assays on podocytes grown under increased glucose concentration (25 mM). Under these conditions, the expression of podocalyxin was almost totally suppressed. The cells adhered and spread to basement membrane components but there was no increase in the extent of adhesion and spreading in the presence of anti-podocalyxin antibody, or ruffling of the cell edges. Additionally, in podocytes expressing podocalyxin, the presence of anti-podocalyxin antibody partially reversed the inhibition of adhesion to collagen IV provoked by anti-beta1 integrin antibody, thus podocalyxin should compete with beta1-related cell adhesion. We suggest that the observed podocalyxin-mediated inhibition of binding to the matrix could be in part responsible for the specialized conformation of the basal surface of podocytes.


title: Mfold web server for nucleic acid folding and hybridization prediction

text: 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'.


title: Grip strength in healthy caucasian adults: reference values.

text: 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.


title: Association Between Biomarkers of Ovarian Reserve and Infertility Among Older Women of Reproductive Age

text: Importance Despite lack of evidence of their utility, biomarkers of ovarian reserve are being promoted as potential markers of reproductive potential. Objective To determine the associations between biomarkers of ovarian reserve and reproductive potential among women of late reproductive age. Design, Setting, and Participants Prospective time-to-pregnancy cohort study (2008 to date of last follow-up in March 2016) of women (N = 981) aged 30 to 44 years without a history of infertility who had been trying to conceive for 3 months or less, recruited from the community in the Raleigh-Durham, North Carolina, area. Exposures Early-follicular-phase serum level of antimüllerian hormone (AMH), follicle-stimulating hormone (FSH), and inhibin B and urinary level of FSH. Main Outcomes and Measures The primary outcomes were the cumulative probability of conception by 6 and 12 cycles of attempt and relative fecundability (probability of conception in a given menstrual cycle). Conception was defined as a positive pregnancy test result. Results A total of 750 women (mean age, 33.3 [SD, 3.2] years; 77% white; 36% overweight or obese) provided a blood and urine sample and were included in the analysis. After adjusting for age, body mass index, race, current smoking status, and recent hormonal contraceptive use, women with low AMH values (<0.7 ng/mL [n = 84]) did not have a significantly different predicted probability of conceiving by 6 cycles of attempt (65%; 95% CI, 50%-75%) compared with women (n = 579) with normal values (62%; 95% CI, 57%-66%) or by 12 cycles of attempt (84% [95% CI, 70%-91%] vs 75% [95% CI, 70%-79%], respectively). Women with high serum FSH values (>10 mIU/mL [n = 83]) did not have a significantly different predicted probability of conceiving after 6 cycles of attempt (63%; 95% CI, 50%-73%) compared with women (n = 654) with normal values (62%; 95% CI, 57%-66%) or after 12 cycles of attempt (82% [95% CI, 70%-89%] vs 75% [95% CI, 70%-78%], respectively). Women with high urinary FSH values (>11.5 mIU/mg creatinine [n = 69]) did not have a significantly different predicted probability of conceiving after 6 cycles of attempt (61%; 95% CI, 46%-74%) compared with women (n = 660) with normal values (62%; 95% CI, 58%-66%) or after 12 cycles of attempt (70% [95% CI, 54%-80%] vs 76% [95% CI, 72%-80%], respectively). Inhibin B levels (n = 737) were not associated with the probability of conceiving in a given cycle (hazard ratio per 1-pg/mL increase, 0.999; 95% CI, 0.997-1.001). Conclusions and Relevance Among women aged 30 to 44 years without a history of infertility who had been trying to conceive for 3 months or less, biomarkers indicating diminished ovarian reserve compared with normal ovarian reserve were not associated with reduced fertility. These findings do not support the use of urinary or blood follicle-stimulating hormone tests or antimüllerian hormone levels to assess natural fertility for women with these characteristics.


title: Matrix-embedded osteocytes regulate mobilization of hematopoietic stem/progenitor cells.

text: 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.


title: Generation of Genetically Modified Mice by Oocyte Injection of Androgenetic Haploid Embryonic Stem Cells

text: Haploid cells are amenable for genetic analysis. Recent success in the derivation of mouse haploid embryonic stem cells (haESCs) via parthenogenesis has enabled genetic screening in mammalian cells. However, successful generation of live animals from these haESCs, which is needed to extend the genetic analysis to the organism level, has not been achieved. Here, we report the derivation of haESCs from androgenetic blastocysts. These cells, designated as AG-haESCs, partially maintain paternal imprints, express classical ESC pluripotency markers, and contribute to various tissues, including the germline, upon injection into diploid blastocysts. Strikingly, live mice can be obtained upon injection of AG-haESCs into MII oocytes, and these mice bear haESC-carried genetic traits and develop into fertile adults. Furthermore, gene targeting via homologous recombination is feasible in the AG-haESCs. Our results demonstrate that AG-haESCs can be used as a genetically tractable fertilization agent for the production of live animals via injection into oocytes.


title: The impact of hydroxyethyl starches in cardiac surgery: a meta-analysis

text: INTRODUCTION Recent studies in septic patients showed that adverse effects of hydroxyethyl starches (HESs) possibly outweigh their benefits in severely impaired physiological haemostasis. It remains unclear whether this also applies to patient populations that are less vulnerable. In this meta-analysis, we evaluated the impact of various HES generations on safety and efficacy endpoints in patients undergoing cardiac surgery. METHODS We searched the PubMed, Embase and Cochrane Central Register of Controlled Trials databases for randomised controlled trials (RCTs) in the English or German language comparing the use of HES to any other colloid or crystalloid during open heart surgery. RESULTS Blood loss and transfusion requirements were higher for older starches with mean molecular weights more than 200 kDa compared to other volume substitutes. In contrast, this effect was not observed with latest-generation tetrastarches (130/0.4), which performed even better when compared to albumin (blood loss of tetrastarch versus albumin: standardised mean difference (SMD), -0.34; 95% CI, -0.63, -0.05; P = 0.02; versus gelatin: SMD, -0.06; 95% CI, -0.20, 0.08; P = 0.39; versus crystalloids: SMD, -0.05; 95% CI, -0.20, 0.10; P = 0.54). Similar results were found for transfusion needs. Lengths of stay in the intensive care unit or hospital were significantly shorter with tetrastarches compared to gelatin (intensive care unit: SMD, -0.10; 95% CI, -0.15, -0.05; P = 0.0002) and crystalloids (hospital: SMD, -0.52; 95% CI, -0.90, -0.14; P = 0.007). CONCLUSIONS In this meta-analysis of RCTs, we could not identify safety issues with tetrastarches compared with other colloid or crystalloid solutions in terms of blood loss, transfusion requirements or hospital length of stay in patients undergoing cardiac surgery. The safety data on coagulation with older starches raise some issues that need to be addressed in future trials.


title: Place of care in advanced cancer: a qualitative systematic literature review of patient preferences.

text: 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.


title: Linkage Disequilibrium Mapping of       CHEK2: Common Variation and Breast Cancer Risk

text: 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.


title: Decoding Mammalian Ribosome-mRNA States by Translational GTPase Complexes

text: 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.


title: Intestinal Cgi-58 Deficiency Reduces Postprandial Lipid Absorption

text: Comparative Gene Identification-58 (CGI-58), a lipid droplet (LD)-associated protein, promotes intracellular triglyceride (TG) hydrolysis in vitro. Mutations in human CGI-58 cause TG accumulation in numerous tissues including intestine. Enterocytes are thought not to store TG-rich LDs, but a fatty meal does induce temporary cytosolic accumulation of LDs. Accumulated LDs are eventually cleared out, implying existence of TG hydrolytic machinery in enterocytes. However, identities of proteins responsible for LD-TG hydrolysis remain unknown. Here we report that intestine-specific inactivation of CGI-58 in mice significantly reduces postprandial plasma TG concentrations and intestinal TG hydrolase activity, which is associated with a 4-fold increase in intestinal TG content and large cytosolic LD accumulation in absorptive enterocytes during the fasting state. Intestine-specific CGI-58 knockout mice also display mild yet significant decreases in intestinal fatty acid absorption and oxidation. Surprisingly, inactivation of CGI-58 in intestine significantly raises plasma and intestinal cholesterol, and reduces hepatic cholesterol, without altering intestinal cholesterol absorption and fecal neutral sterol excretion. In conclusion, intestinal CGI-58 is required for efficient postprandial lipoprotein-TG secretion and for maintaining hepatic and plasma lipid homeostasis. Our animal model will serve as a valuable tool to further define how intestinal fat metabolism influences the pathogenesis of metabolic disorders, such as obesity and type 2 diabetes.


title: Transglutaminase 2 Undergoes a Large Conformational Change upon Activation

text: Human transglutaminase 2 (TG2), a member of a large family of enzymes that catalyze protein crosslinking, plays an important role in the extracellular matrix biology of many tissues and is implicated in the gluten-induced pathogenesis of celiac sprue. Although vertebrate transglutaminases have been studied extensively, thus far all structurally characterized members of this family have been crystallized in conformations with inaccessible active sites. We have trapped human TG2 in complex with an inhibitor that mimics inflammatory gluten peptide substrates and have solved, at 2-A resolution, its x-ray crystal structure. The inhibitor stabilizes TG2 in an extended conformation that is dramatically different from earlier transglutaminase structures. The active site is exposed, revealing that catalysis takes place in a tunnel, bridged by two tryptophan residues that separate acyl-donor from acyl-acceptor and stabilize the tetrahedral reaction intermediates. Site-directed mutagenesis was used to investigate the acyl-acceptor side of the tunnel, yielding mutants with a marked increase in preference for hydrolysis over transamidation. By providing the ability to visualize this activated conformer, our results create a foundation for understanding the catalytic as well as the non-catalytic roles of TG2 in biology, and for dissecting the process by which the autoantibody response to TG2 is induced in celiac sprue patients.


title: Lactic acidosis in patients with diabetes treated with metformin.

text: To the Editor: From May 1995, when metformin was introduced in the United States, through June 30, 1996, the Food and Drug Administration (FDA) received reports of lactic acidosis in 66 patients treated with metformin. In 47 patients, the diagnosis was confirmed on the basis of circulating lactate values (>5 mmol per liter), in accordance with established criteria for the diagnosis of lactic acidosis (Table 1).1,2 Of the 47 patients with confirmed diagnoses, 43 had one or more risk factors for lactic acidosis. Thirty (64 percent) had preexisting cardiac disease, of whom 18 had histories of congestive heart failure. . . .


title: The Apaf-1 apoptosome induces formation of caspase-9 homo- and heterodimers with distinct activities

text: 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.


title: Repositioning of aurora B promoted by chiasmata ensures sister chromatid mono-orientation in meiosis I.

text: 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.


title: Biophysical Constraints Arising from Compositional Context in Synthetic Gene Networks.

text: Synthetic gene expression is highly sensitive to intragenic compositional context (promoter structure, spacing regions between promoter and coding sequences, and ribosome binding sites). However, much less is known about the effects of intergenic compositional context (spatial arrangement and orientation of entire genes on DNA) on expression levels in synthetic gene networks. We compare expression of induced genes arranged in convergent, divergent, or tandem orientations. Induction of convergent genes yielded up to 400% higher expression, greater ultrasensitivity, and dynamic range than divergent- or tandem-oriented genes. Orientation affects gene expression whether one or both genes are induced. We postulate that transcriptional interference in divergent and tandem genes, mediated by supercoiling, can explain differences in expression and validate this hypothesis through modeling and in vitro supercoiling relaxation experiments. Treatment with gyrase abrogated intergenic context effects, bringing expression levels within 30% of each other. We rebuilt the toggle switch with convergent genes, taking advantage of supercoiling effects to improve threshold detection and switch stability.


title: Glucose repression in Saccharomyces cerevisiae

text: 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.


title: The p21 Cdk-interacting protein Cip1 is a potent inhibitor of G1 cyclin-dependent kinases.

text: The cyclin-dependent kinase Cdk2 associates with cyclins A, D, and E and has been implicated in the control of the G1 to S phase transition in mammals. To identify potential Cdk2 regulators, we have employed an improved two-hybrid system to isolate human genes encoding Cdk-interacting proteins (Cips). CIP1 encodes a novel 21 kd protein that is found in cyclin A, cyclin D1, cyclin E, and Cdk2 immunoprecipitates. p21CIP1 is a potent, tight-binding inhibitor of Cdks and can inhibit the phosphorylation of Rb by cyclin A-Cdk2, cyclin E-Cdk2, cyclin D1-Cdk4, and cyclin D2-Cdk4 complexes. Cotransfection experiments indicate that CIP1 and SV40 T antigen function in a mutually antagonistic manner to control cell cycle progression.


title: Exploring the temporal structure of heterochronous sequences using TempEst (formerly Path-O-Gen)

text: Gene sequences sampled at different points in time can be used to infer molecular phylogenies on a natural timescale of months or years, provided that the sequences in question undergo measurable amounts of evolutionary change between sampling times. Data sets with this property are termed heterochronous and have become increasingly common in several fields of biology, most notably the molecular epidemiology of rapidly evolving viruses. Here we introduce the cross-platform software tool, TempEst (formerly known as Path-O-Gen), for the visualization and analysis of temporally sampled sequence data. Given a molecular phylogeny and the dates of sampling for each sequence, TempEst uses an interactive regression approach to explore the association between genetic divergence through time and sampling dates. TempEst can be used to (1) assess whether there is sufficient temporal signal in the data to proceed with phylogenetic molecular clock analysis, and (2) identify sequences whose genetic divergence and sampling date are incongruent. Examination of the latter can help identify data quality problems, including errors in data annotation, sample contamination, sequence recombination, or alignment error. We recommend that all users of the molecular clock models implemented in BEAST first check their data using TempEst prior to analysis.