Venous thromboembolism (VTE), including deep vein thrombosis (DVT) and pulmonary embolism (PE), may be the number one preventable cause of death associated with hospitalization. Numerous evidence-based guidelines for effective VTE prophylaxis therapy exist. However, underuse is common due to the difficulty in integrating VTE risk assessment into routine patient care. Previous studies utilizing computer decision support to identify high-risk patients report improved use of prophylaxis therapy and reduced VTE. However, those studies did not report the sensitivity, specificity or positive predictive value of their methods to identify patients at high risk. We report an evaluation of a computerized tool to identify patients at high risk for VTE that found a sensitivity of 98% and positive predictive value of 99%. Another computer program used to detect VTE had a sensitivity of 92%, specificity of 99% and a positive predictive value of 97% to identify DVT and a sensitivity of 100%, specificity of 98% and positive predictive value of 89% to identify PE. These tools were found to provide a dependable method to identify patients at high risk for and with VTE.
Breast cancer exhibits familial aggregation, consistent with variation in genetic susceptibility to the disease. Known susceptibility genes account for less than 25% of the familial risk of breast cancer, and the residual genetic variance is likely to be due to variants conferring more moderate risks. To identify further susceptibility alleles, we conducted a two-stage genome-wide association study in 4,398 breast cancer cases and 4,316 controls, followed by a third stage in which 30 single nucleotide polymorphisms (SNPs) were tested for confirmation in 21,860 cases and 22,578 controls from 22 studies. We used 227,876 SNPs that were estimated to correlate with 77% of known common SNPs in Europeans at r2>0.5. SNPs in five novel independent loci exhibited strong and consistent evidence of association with breast cancer (P<10−7). Four of these contain plausible causative genes (FGFR2, TNRC9, MAP3K1 and LSP1). At the second stage, 1,792 SNPs were significant at the P<0.05 level compared with an estimated 1,343 that would be expected by chance, indicating that many additional common susceptibility alleles may be identifiable by this approach.
Recently it has been demonstrated that moderate heat treatment of Amphotericin B/deoxycholate solutions (HAmB-DOC) leads to a therapeutically interesting supramolecular rearrangement that can be observed by significant changes in light scattering, CD, and absorbance. In this study, we continue the investigation of the physical properties of this new form by evaluating the activity and kinetics of dissociation and dispersion of HAmB-DOC and AmB-DOC in saline, serum, and in model mammalian or fungal lipid biomimetic membrane vesicles. Stopped-flow spectrophotometry combined with singular value decomposition (SVD) and global analysis were used to resolve the components of this process. The dissociation kinetics for both states are complex, requiring multiexponential fits, vet in most cases SVD indicates only two significant changing species representing the monomer and the aggregate. The kinetic mechanism could involve dissociation of monomers from coexisting spectroscopically similar but structurally distinct aggregates or sequential rearrangements in supramolecular structure of aggregates. Rate constants and amplitudes of dissociation from aggregates to monomer in buffer, whole serum, 10% cholesterol, and ergosterol membrane vesicles are generally greater for AmB-DOC, demonstrating its greater kinetic instability. In addition, at comparable low concentrations, HAmB-DOC and AmB-DOC are nearly equally active at promoting cation selective permeability in ergosterol-containing membranes; however, HAmB-DOC is much less active against mammalian mimetic cholesterol-containing vesicles, despite a higher level of self-association, supporting previous observations that there exists a specific “toxic aggregate” structure.
To explore the variability in biosensor studies, 150 participants from 20 countries were given the same protein samples and asked to determine kinetic rate constants for the interaction. We chose a protein system that was amenable to analysis using different biosensor platforms as well as by users of different expertise levels. The two proteins (a 50-kDa Fab and a 60-kDa glutathione S-transferase [GST] antigen) form a relatively high-affinity complex, so participants needed to optimize several experimental parameters, including ligand immobilization and regeneration conditions as well as analyte concentrations and injection/dissociation times. Although most participants collected binding responses that could be fit to yield kinetic parameters, the quality of a few data sets could have been improved by optimizing the assay design. Once these outliers were removed, the average reported affinity across the remaining panel of participants was 620 pM with a standard deviation of 980 pM. These results demonstrate that when this biosensor assay was designed and executed appropriately, the reported rate constants were consistent, and independent of which protein was immobilized and which biosensor was used.
Biacore; Kinetics; Optical biosensor; Surface plasmon resonance
To determine optimal delay times and flip angles for T1-weighted hepatobiliary imaging at 1.5T with gadoxetic acid and to demonstrate the feasibility of using a high-resolution navigated optimized T1-weighted pulse sequence to evaluate biliary disease.
Materials and Methods
Eight healthy volunteers were scanned at 1.5T using a T1-weighted 3D-SPGR pulse sequence following the administration of 0.05 mmol/kg of gadoxetic acid. Navigator-gating enabled acquisition of high spatial resolution (1.2 × 1.4 × 1.8 mm3, interpolated to 0.7 × 0.7 × 0.9 mm3) images in approximately 5 minutes of free breathing. Multiple breath-held acquisitions were performed at flip angles between 15° and 45° to optimize T1 weighting. To evaluate the performance of this optimized sequence in the setting of biliary disease, the image quality and biliary excretion of 51 consecutive clinical scans performed to assess primary sclerosing cholangitis (PSC) were evaluated.
Optimal hepatobiliary imaging occurs at 15–25 minutes, using a 40° flip angle. The image quality and visualization of biliary excretion in the PSC scans were excellent, despite the decreased liver function in some patients. Visualization of reduced excretion often provided diagnostic information that was unavailable by conventional magnetic resonance cholangiopancreatography (MRCP).
High-resolution navigated 3D-SPGR hepatobiliary imaging using gadoxetic acid and optimized scan parameters is technically feasible and can be clinically useful, even in patients with decreased hepatobiliary function.
magnetic resonance; liver imaging; navigator; gadoxetic acid; optimization; primary sclerosing cholangitis
Cystic fibrosis (CF), the most common life-shortening genetic disorder in Caucasians, affects approximately 70 000 individuals worldwide. In 1998, the Cystic Fibrosis Foundation (CFF) launched the CF Therapeutics Development Network (CF-TDN) as a central element of its Therapeutics Development Programme. Designed to accelerate the clinical evaluation of new therapies needed to fulfil the CFF mission to control and cure CF, the CF-TDN has conducted 75 clinical trials since its inception, and has contributed to studies as varied as initial safety and proof of concept trials to pivotal programmes required for regulatory approval. This review highlights recent and significant research efforts of the CF-TDN, including a summary of contributions to studies involving CF transmembrane conductance regulator (CFTR) modulators, airway surface liquid hydrators and mucus modifiers, anti-infectives, anti-inflammatories, and nutritional therapies. Efforts to advance CF biomarkers, necessary to accelerate the therapeutic goals of the network, are also summarised.
Neuroimaging studies have revealed functional abnormalities in the
anterior cingulate cortex in posttraumatic stress disorder (PTSD). The goal
of the current research was to determine whether hyperresponsivity of the
dorsal anterior cingulate in PTSD is an acquired characteristic or familial
Using a case-control twin design, we studied combat-exposed veterans
with PTSD (n=12) and their identical combat-unexposed co-twins
(n=12), as well as combat-exposed veterans without PTSD
(n=14) and their identical combat-unexposed co-twins (n=14).
Participants underwent functional magnetic resonance imaging during
completion of the Multi-Source Interference Task, which reliably activates
the dorsal anterior cingulate.
Combat veterans with PTSD and their co-twins had significantly
greater activation in the dorsal anterior cingulate and tended to have
larger response time difference scores, as compared to non-PTSD veterans and
their co-twins. Dorsal anterior cingulate activation in the exposed twins
was positively correlated with their PTSD symptom severity. Dorsal anterior
cingulate activation in the unexposed twins was positively
correlated with their combat-exposed co-twins’ PTSD symptom
severity, but not with depression or alcohol use severity in the
Hyperresponsivity in the dorsal anterior cingulate appears to be a
familial risk factor for the development of PTSD following psychological
magnetic resonance imaging; limbic system; stress disorders; post-traumatic; twins; monozygotic; gyrus cinguli; Multi-Source Interference Task
To investigate the value of gadoxetic acid-enhanced 3-dimensional T1-weighted MR cholangiography (T1w-MRC) in comparison to 3-dimensional T2-weighted MR cholangiopancreaticography (T2w-MRCP) in patients with primary sclerosing cholangitis (PSC).
Subjects and Methods
Thirty-four MR exams in 29 patients (46.0±16.1 years; 19 men, 10 women) scanned within a 14-month-period were retrospectively included. Two abdominal radiologists independently evaluated image quality regarding image contrast, image quality degradation due to artifacts, and visualization quality of ducts. The order of biliary tree branches that were visualized and reader preference towards each method were recorded. Helpfulness of T1w-MRC was scored in consensus. Confirmatory endoscopic retrograde cholangiopancreaticography (ERCP) performed within 3 months of the MR examination was available in 8 patients.
Image quality of T1w-MRC and T2w-MRCP was graded good to excellent in all cases. There were advantages for both T1w-MRC (functional information, less degradation due to artifacts) and T2w-MRCP (higher order of visualized branches, better branch depiction). Both readers showed preference for T2w-MRCP; however, both readers found gadoxetic acid–enhanced T1w-MRC helpful in the majority of cases.
Gadoxetic acid-enhanced T1w-MRC is complementary to, but should not replace, T2w-MRCP. T1w-MRC is a useful adjunct to T2w-MRCP for morphologic evaluation and provides additional diagnostic information.
Primary sclerosing cholangitis; magnetic resonance cholangiography; T1-weighted MR cholangiography; T2-weighted MR cholangiopancreaticography; gadoxetic acid; hepatobiliary contrast enhancement
Adiponectin has anti-diabetic properties and patients with obesity, diabetes and insulin resistance have low plasma adiponectin levels. However, although kidney disease is associated with insulin resistance, adiponectin is elevated in end stage renal disease. Here we determine if adipose tissue production of adiponectin is increased in renal disease in a case-control study of 36 patients with end stage renal disease and 23 kidney donors. Blood and tissue samples were obtained at kidney transplantation and donation. The mean plasma adiponectin level was significantly increased to 15.6 mg/ml in cases compared to 8.4 mg/ml in controls. Plasma levels of the inflammatory adipokines tumor necrosis factor α, interleukin 6 and high sensitivity C-reactive protein were significantly higher in cases compared to controls. Adiponectin mRNA and protein expression in visceral and subcutaneous fat was significantly higher in cases than controls while adiponectin receptor 1 mRNA expression was significantly increased in peripheral blood cells, muscle and adipose tissue in cases compared to controls. Thus, our study suggests that adipose tissue production of adiponectin contributes to the high plasma levels seen in end stage renal disease.
adiponectin; inflammation; end-stage renal disease
Zambia adopted Option A for prevention of mother-to-child transmission of HIV (PMTCT) in 2010 and announced a move to Option B+ in 2013. We evaluated the uptake, outcomes, and costs of antenatal, well-baby, and PMTCT services under routine care conditions in Zambia after the adoption of Option A.
We enrolled 99 HIV-infected/HIV-exposed (index) mother/baby pairs with a first antenatal visit in April-September 2011 at four study sites and 99 HIV-uninfected/HIV-unexposed (comparison) mother/baby pairs matched on site, gestational age, and calendar month at first visit. Data on patient outcomes and resources utilized from the first antenatal visit through six months postpartum were extracted from site registers. Costs in 2011 USD were estimated from the provider’s perspective.
Index mothers presented for antenatal care at a mean 23.6 weeks gestation; 55% were considered to have initiated triple-drug antiretroviral therapy (ART) based on information recorded in site registers. Six months postpartum, 62% of index and 30% of comparison mother/baby pairs were retained in care; 67% of index babies retained had an unknown HIV status. Comparison and index mother/baby pairs utilized fewer resources than under fully guideline-concordant care; index babies utilized more well-baby resources than comparison babies. The average cost per comparison pair retained in care six months postpartum was $52 for antenatal and well-baby services. The average cost per index pair retained was $88 for antenatal, well-baby, and PMTCT services and increased to $185 when costs of triple-drug ART services were included.
HIV-infected mothers present to care late in pregnancy and many are lost to follow up by six months postpartum. HIV-exposed babies are more likely to remain in care and receive non-HIV, well-baby care than HIV-unexposed babies. Improving retention in care, guideline concordance, and moving to Option B+ will result in increased service delivery costs in the short term.
Recent neuroimaging research has revealed functional abnormalities in the anterior cingulate cortex, amygdala and hippocampus in posttraumatic stress disorder (PTSD).
To determine whether resting functional abnormalities found in PTSD are acquired characteristics or familial risk factors.
Cross-sectional design including identical twins discordant for trauma exposure.
Academic medical center.
Combat-exposed veterans with PTSD (n=14) and their identical, combat-unexposed co-twins (n=14), as well as combat-exposed veterans without PTSD (n=19) and their identical, combat-unexposed co-twins (n=19).
Main Outcome Measures
We used positron emission tomography and [18F]-fluorodeoxyglucose to examine resting regional cerebral metabolic rates for glucose (rCMRglu).
Veterans with PTSD and their co-twins had significantly higher resting rCMRglu in dorsal anterior cingulate/mid cingulate cortex (dACC/MCC) compared to non-PTSD veterans and their co-twins. Resting rCMRglu in dACC/MCC in the combat-unexposed co-twins was positively correlated with combat exposure severity, PTSD symptom severity, and alcohol use in their exposed twins.
Enhanced resting metabolic activity in dACC/MCC appears to represent a familial risk factor for developing PTSD after exposure to psychological trauma.
stress disorders; post-traumatic; twins; monozygotic; positron-emission tomography; fluorodexoyglucose F18; metabolism; cingulate gyrus
Severe malaria can trigger acute lung injury characterized by pulmonary edema resulting from increased endothelial permeability. However, the mechanism through which lung fluid conductance is altered during malaria remains unclear. To define the role that the scavenger receptor CD36 may play in mediating this response, C57BL/6J (WT) and CD36−/− mice were infected with P. berghei ANKA and monitored for changes in pulmonary endothelial barrier function employing an isolated perfused lung system. WT lungs demonstrated a >10-fold increase in two measures of paracellular fluid conductance and a decrease in the albumin reflection coefficient (σalb) compared to control lungs indicating a loss of barrier function. In contrast, malaria-infected CD36−/− mice had near normal fluid conductance but a similar reduction in σalb. In WT mice, lung sequestered iRBCs demonstrated production of reactive oxygen species (ROS). To determine whether knockout of CD36 could protect against ROS-induced endothelial barrier dysfunction, mouse lung microvascular endothelial monolayers (MLMVEC) from WT and CD36−/− mice were exposed to H2O2. Unlike WT monolayers, which showed dose-dependent decreases in transendothelial electrical resistance (TER) from H2O2 indicating loss of barrier function, CD36−/− MLMVEC demonstrated dose-dependent increases in TER. The differences between responses in WT and CD36−/− endothelial cells correlated with important differences in the intracellular compartmentalization of the CD36-associated Fyn kinase. Malaria infection increased total lung Fyn levels in CD36−/− lungs compared to WT, but this increase was due to elevated production of the inactive form of Fyn further suggesting a dysregulation of Fyn-mediated signaling. The importance of Fyn in CD36-dependent endothelial signaling was confirmed using in vitro Fyn knockdown as well as Fyn−/− mice, which were also protected from H2O2- and malaria-induced lung endothelial leak, respectively. Our results demonstrate that CD36 and Fyn kinase are critical mediators of the increased lung endothelial fluid conductance caused by malaria infection.
Schizophrenia is associated with abnormalities in emotional processing and social cognition, which may result from disruption of the underlying neural mechanism(s) governing emotional learning and memory. To investigate this possibility, we measured the acquisition and extinction of conditioned fear responses and delayed recall of extinction in schizophrenia and control subjects.
28 schizophrenia and 18 demographically-matched control subjects underwent a two-day fear conditioning, extinction learning and extinction recall procedure, in which skin conductance response (SCR) magnitude was used as the index of conditioned responses.
During fear acquisition, 83% of the controls and 57% of the patients showed autonomic responsivity (‘responders’), and the patients showed larger SCRs to the stimulus that was not paired with the unconditioned stimulus (CS−) than the controls. Within the responder group, there was no difference between the patients and controls in levels of extinction learning; however, the schizophrenia patients showed significant impairment, relative to the controls, in context-dependent recall of the extinction memory. In addition, delusion severity in the patients correlated with baseline skin conductance levels.
These data are consistent with prior evidence for a heightened neural response to innocuous stimuli in schizophrenia and elevated arousal levels in psychosis. The finding of deficient extinction recall in schizophrenia patients who showed intact extinction learning suggests that schizophrenia is associated with a disturbance in the neural processes supporting emotional memory.
schizophrenia; fear; conditioning; extinction; emotion; memory
The scaffolding protein WAVE-1 (Wiskott-Aldrich syndrome protein family member 1) directs signals from the GTPase Rac through the Arp2/3 complex to facilitate neuronal actin remodeling. The WAVE-associated GTPase activating protein called WRP is implicated in human mental retardation, and WAVE-1 knock-out mice have altered behavior. Neuronal time-lapse imaging, behavioral analyses, and electrophysiological recordings from genetically modified mice were used to show that WAVE-1 signaling complexes control aspects of neuronal morphogenesis and synaptic plasticity. Gene targeting experiments in mice demonstrate that WRP anchoring to WAVE-1 is a homeostatic mechanism that contributes to neuronal development and the fidelity of synaptic connectivity. This implies that signaling through WAVE-1 complexes is essential for neural plasticity and cognitive behavior.
WAVE-1; WRP; actin; Arp2/3; dendritic spine; synaptic plasticity
Alcohol drinking by adolescents is a major public health concern. Adolescents tend to drink in a chronic, intermittent, that is, “binge,” pattern, and such patterns of ethanol exposure are associated with increased risk of neurotoxicity and the development of alcohol use disorders (Crews et al., 2000; Hunt, 1993). Both adolescent humans and rats are more sensitive to acute ethanol-induced memory impairment than adults (Acheson et al., 1998; Markwiese et al., 1998). Furthermore, in rats, chronic intermittent ethanol (CIE) exposure during adolescence produces a long-lasting, perhaps permanent, maintenance of the adolescent high sensitivity to ethanol’s amnestic effects (White et al., 2000a). We have previously shown that acute ethanol increases tonic inhibitory current mediated by extrasynaptic GABAA receptors more efficaciously in dentate granule cells (DGCs) from adolescent than adult rats (Fleming et al., 2007). In this study, we determined if CIE during adolescence produced long-lasting changes in this tonic current.
Adolescent rats were subjected to a CIE exposure regimen and allowed to mature to full adulthood. Whole-cell voltage-clamp measurements of tonic inhibitory current and mean phasic current were made in vitro in hippocampal brain slices.
CIE exposure during adolescence increased the ethanol sensitivity of tonic inhibitory current mediated by extrasynaptic GABAA receptors and decreased the ethanol sensitivity of phasic, synaptic GABAA receptor-mediated current in adult DGCs.
CIE exposure during adolescence produces long-lasting changes in the function and ethanol sensitivity of extrasynaptic GABAA receptors in DGCs. These changes appear to “lock-in” and maintain the high adolescent sensitivity to ethanol in these cells. Furthermore, greater ethanol enhancement of tonic inhibition in the hippocampal formation after CIE is consistent with the greater sensitivity to ethanol-induced memory impairment after adolescent CIE. This finding represents the first demonstration of a long-term, memory-related cellular effect of CIE during adolescence, and the “lock-in” of adolescent ethanol sensitivity that these results suggest could represent a conceptual step forward in understanding the vulnerability of the adolescent brain to alcohol.
Ethanol; Extrasynaptic GABAA Receptor; Tonic Inhibition; Dentate Gyrus; Adolescence
Oxidative stress contributes to many disease etiologies including ageing, neurodegeneration, and cancer, partly through DNA damage induction (genotoxicity). Understanding the i nteractions of free radicals with DNA is fundamental to discern mutation risks. In genetic toxicology, regulatory authorities consider that most genotoxins exhibit a linear relationship between dose and mutagenic response. Yet, homeostatic mechanisms, including DNA repair, that allow cells to tolerate low levels of genotoxic exposure exist. Acceptance of thresholds for genotoxicity has widespread consequences in terms of understanding cancer risk and regulating human exposure to chemicals/drugs. Three pro-oxidant chemicals, hydrogen peroxide (H2O2), potassium bromate (KBrO3), and menadione, were examined for low dose-response curves in human lymphoblastoid cells. DNA repair and antioxidant capacity were assessed as possible threshold mechanisms. H2O2 and KBrO3, but not menadione, exhibited thresholded responses, containing a range of nongenotoxic low doses. Levels of the DNA glycosylase 8-oxoguanine glycosylase were unchanged in response to pro- oxidant stress. DNA repair–focused gene expression arrays reported changes in ATM and BRCA1, involved in double-strand break repair, in response to low-dose pro-oxidant exposure; however, these alterations were not substantiated at the protein level. Determination of oxidatively induced DNA damage in H2O2-treated AHH-1 cells reported accumulation of thymine glycol above the genotoxic threshold. Further, the H2O2 dose-response curve was shifted by modulating the antioxidant glutathione. Hence, observed pro- oxidant thresholds were due to protective capacities of base excision repair enzymes and antioxidants against DNA damage, highlighting the importance of homeostatic mechanisms in “genotoxic tolerance.”
Pro-oxidants; DNA damage; reactive oxygen species; DNA repair; OGG1; antioxidants; glutathione; genotoxicology; thresholds.
The human population is currently faced with the potential use of natural or recombinant variola and monkeypox viruses as biological weapons. Furthermore, the emergence of human monkeypox in Africa and its expanding environs poses a significant natural threat. Such occurrences would require therapeutic and prophylactic intervention with antivirals to minimize morbidity and mortality of exposed populations. Two orally-bioavailable antivirals are currently in clinical trials; namely CMX001, an ether-lipid analogue of cidofovir with activity at the DNA replication stage and ST-246, a novel viral egress inhibitor. Both of these drugs have previously been evaluated in the ectromelia/mousepox system; however, the trigger for intervention was not linked to a disease biomarker or a specific marker of virus replication. In this study we used lethal, intranasal, ectromelia virus infections of C57BL/6 and hairless SKH1 mice to model human disease and evaluate exanthematous rash (rash) as an indicator to initiate antiviral treatment. We show that significant protection can be provided to C57BL/6 mice by CMX001 or ST-246 when therapy is initiated on day 6 post infection or earlier. We also show that significant protection can be provided to SKH1 mice treated with CMX001 at day 3 post infection or earlier, but this is 4 or more days before detection of rash (ST-246 not tested). Although in this model rash could not be used as a treatment trigger, viral DNA was detected in blood by day 4 post infection and in the oropharyngeal secretions (saliva) by day 2-3 post infection – thus providing robust and specific markers of virus replication for therapy initiation. These findings are discussed in the context of current respiratory challenge animal models in use for the evaluation of poxvirus antivirals.
Ectromelia; bioterrorism; rash; variola; monkeypox; smallpox; biological weapon
This phase I study aims at assessing the safety and tolerability of LY2603618, a selective inhibitor of Checkpoint Kinase 1, in combination with pemetrexed and determining the maximum tolerable dose and the pharmacokinetic parameters.
This was an open-label, multicenter, dose-escalation study in patients with advanced solid tumors. Increasing doses of LY2603618 (40–195 mg/m2) were combined with 500 mg/m2 of pemetrexed. LY2603618 was administered on Days 1 and 9 and pemetrexed on Day 8 in a 28-day cycle. For all subsequent 21-day cycles, pemetrexed was administered on Day 1 and LY2603618 on Day 2. Anti-tumor activity was evaluated as per Response Evaluation Criteria in Solid Tumors 1.0.
A total of 31 patients were enrolled into six cohorts (three at 40 mg/m2 over 4.5-hour infusion, 1-hour infusion in subsequent cohorts: three each at 40 mg/m2, 70 mg/m2, and 195 mg/m2; 13 at 105 mg/m2; six at 150 mg/m2). Four patients experienced a dose-limiting toxicity: diarrhea (105 mg/m2); reversible infusion-related reaction (150 mg/m2); thrombocytopenia (195 mg/m2); and fatigue (195 mg/m2). The maximum tolerated dose was defined as 150 mg/m2. The pharmacokinetic data demonstrated that the exposure of LY2603618 increased in a dose-dependent manner, displayed a suitable half-life for maintaining required human exposures while minimizing the intra- and inter-cycle accumulation, and was unaffected by the pemetrexed administration. The pharmacokinetic-defined biologically efficacious dose was achieved at doses ≥105 mg/m2.
LY2603618 administered approximately 24 h after pemetrexed showed acceptable safety and pharmacokinetic profiles.
LY2603618; Pemetrexed; Checkpoint kinase; inhibitor; Cancer
Deedu (DU) Mongolians, who migrated from the Mongolian steppes to the Qinghai-Tibetan Plateau approximately 500 years ago, are challenged by environmental conditions similar to native Tibetan highlanders. Identification of adaptive genetic factors in this population could provide insight into coordinated physiological responses to this environment. Here we examine genomic and phenotypic variation in this unique population and present the first complete analysis of a Mongolian whole-genome sequence. High-density SNP array data demonstrate that DU Mongolians share genetic ancestry with other Mongolian as well as Tibetan populations, specifically in genomic regions related with adaptation to high altitude. Several selection candidate genes identified in DU Mongolians are shared with other Asian groups (e.g., EDAR), neighboring Tibetan populations (including high-altitude candidates EPAS1, PKLR, and CYP2E1), as well as genes previously hypothesized to be associated with metabolic adaptation (e.g., PPARG). Hemoglobin concentration, a trait associated with high-altitude adaptation in Tibetans, is at an intermediate level in DU Mongolians compared to Tibetans and Han Chinese at comparable altitude. Whole-genome sequence from a DU Mongolian (Tianjiao1) shows that about 2% of the genomic variants, including more than 300 protein-coding changes, are specific to this individual. Our analyses of DU Mongolians and the first Mongolian genome provide valuable insight into genetic adaptation to extreme environments.
Throughout history, Mongolians have survived the harsh conditions of northern latitudes, including seasonal cold, drought, and a restricted diet. Approximately 500 years ago, nomadic Deedu (DU; “at high altitude”) Mongolians migrated from the Mongolian steppes to the northeastern highlands of the Qinghai-Tibetan Plateau. Using high-density SNP data, we demonstrate that present-day DU Mongolians share genetic ancestry with other Mongolians and with Tibetans. High-altitude selection candidate genes previously identified in the latter population (EPAS1, PKLR, CYP2E1), and PPARG, a gene long hypothesized to play a role in metabolic adaptation, are among the strongest adaptive signals in DU Mongolians. Furthermore, we show that hemoglobin concentration, associated with high-altitude adaptation in Tibetans, is intermediate in DU Mongolians compared to Tibetans and Han Chinese at comparable altitudes. Whole-genome sequence from a DU Mongolian shows that approximately 300 protein-coding changes are specific to this individual. Our analyses provide new perspectives on genetic variation and adaptation to extreme environments.
Arylstibonates structurally resemble phosphotyrosine side chains in proteins and here we addressed the ability of such compounds to act as inhibitors of a panel of mammalian tyrosine and dual-specificity phosphatases. Two arylstibonates both possessing a carboxylate side chain were identified as potent inhibitors of the protein tyrosine phosphatase PTP-β. In addition, they inhibited the dual-specificity, cell cycle regulatory phosphatases Cdc25a and Cdc25b with sub-micromolar potency. However, the Cdc25c phosphatase was not affected demonstrating that arylstibonates may be viable leads from which to develop isoform specific Cdc25 inhibitors.
Arylstibonic acids; protein tyrosine phosphatase; Cdc25 inhibitor
The expansion of repressive epigenetic marks has been implicated in heterochromatin formation during embryonic development, but the general applicability of this mechanism is unclear. Here we show that nuclear rearrangement of repressive histone marks H3K9me3 and H3K27me3 into nonoverlapping structural layers characterizes senescence-associated heterochromatic foci (SAHF) formation in human fibroblasts. However, the global landscape of these repressive marks remains unchanged upon SAHF formation, suggesting that in somatic cells, heterochromatin can be formed through the spatial repositioning of pre-existing repressively marked histones. This model is reinforced by the correlation of presenescent replication timing with both the subsequent layered structure of SAHFs and the global landscape of the repressive marks, allowing us to integrate microscopic and genomic information. Furthermore, modulation of SAHF structure does not affect the occupancy of these repressive marks, nor vice versa. These experiments reveal that high-order heterochromatin formation and epigenetic remodeling of the genome can be discrete events.
We present a method for direct non-optical quantification of dry mass, dry density and water mass of single living cells in suspension. Dry mass and dry density are obtained simultaneously by measuring a cell’s buoyant mass sequentially in an H2O-based fluid and a D2O-based fluid. Rapid exchange of intracellular H2O for D2O renders the cell’s water content neutrally buoyant in both measurements, and thus the paired measurements yield the mass and density of the cell’s dry material alone. Utilizing this same property of rapid water exchange, we also demonstrate the quantification of intracellular water mass. In a population of E. coli, we paired these measurements to estimate the percent dry weight by mass and volume. We then focused on cellular dry density – the average density of all cellular biomolecules, weighted by their relative abundances. Given that densities vary across biomolecule types (RNA, DNA, protein), we investigated whether we could detect changes in biomolecular composition in bacteria, fungi, and mammalian cells. In E. coli, and S. cerevisiae, dry density increases from stationary to exponential phase, consistent with previously known increases in the RNA/protein ratio from up-regulated ribosome production. For mammalian cells, changes in growth conditions cause substantial shifts in dry density, suggesting concurrent changes in the protein, nucleic acid and lipid content of the cell.
Japanese macaque rhadinovirus (JMRV) is a novel gamma-2 herpesvirus that was isolated from a Japanese macaque (JM) with an inflammatory demyelinating encephalomyelitis referred to as Japanese macaque encephalomyelitis, a disease that possesses clinical and histopathological features resembling multiple sclerosis in humans. Genomic DNA sequence analysis reveals that JMRV is a gammaherpesvirus closely related to rhesus macaque rhadinovirus (RRV) and human herpesvirus 8. We describe here the complete nucleotide sequence and structure of the JMRV genome, as well as the sequence of two plaque isolates of this virus. Analysis of the JMRV genome not only demonstrates that this virus shares a number of genes with RRV that may be involved in pathogenesis but also indicates the presence of unique JMRV genes that could potentially contribute to disease development. The knowledge of the genomic sequence of JMRV, and the ability to easily propagate the virus in vitro, make JMRV infection of JM an attractive model for examining the potential role of an infectious viral agent in the development of demyelinating encephalomyelitis disease in vivo.