Quantitative high-throughput screening for chemical toxicity in a population-based in vitro model

A shift in toxicity testing from in vivo to in vitro may efficiently prioritize compounds, reveal new mechanisms, and enable predictive modeling. Quantitative high-throughput screening (qHTS) is a major source of data for computational toxicology, and our goal in this study was to aid in the development of predictive in vitro models of chemical-induced toxicity, anchored on interindividual genetic variability. Eighty-one human lymphoblast cell lines from 27 Centre d'Etude du Polymorphisme Humain trios were exposed to 240 chemical substances (12 concentrations, 0.26nM-46.0μM) and evaluated for cytotoxicity and apoptosis. qHTS screening in the genetically defined population produced robust and reproducible results, which allowed for cross-compound, cross-assay, and cross-individual comparisons. Some compounds were cytotoxic to all cell types at similar concentrations, whereas others exhibited interindividual differences in cytotoxicity. Specifically, the qHTS in a population-based human in vitro model system has several unique aspects that are of utility for toxicity testing, chemical prioritization, and high-throughput risk assessment. First, standardized and high-quality concentration-response profiling, with reproducibility confirmed by comparison with previous experiments, enables prioritization of chemicals for variability in interindividual range in cytotoxicity. Second, genome-wide association analysis of cytotoxicity phenotypes allows exploration of the potential genetic determinants of interindividual variability in toxicity. Furthermore, highly significant associations identified through the analysis of population-level correlations between basal gene expression variability and chemical-induced toxicity suggest plausible mode of action hypotheses for follow-up analyses. We conclude that as the improved resolution of genetic profiling can now be matched with high-quality in vitro screening data, the evaluation of the toxicity pathways and the effects of genetic diversity are now feasible through the use of human lymphoblast cell lines.     

A history of early stent thrombosis is associated with prolonged clot lysis time

It has been demonstrated that formation of compact plasma fibrin clots resistant to plasmin-mediated lysis characterises patients following in-stent thrombosis (IST). The relationship between defective fibrinolysis, reflected as prolonged clot lysis time (CLT) and IST is unclear. We sought to investigate whether patients with acute and subacute IST have impaired fibrinolytic capacity. We studied 41 definite IST patients, including 15 with acute and 26 with subacute IST experienced 2-73 months prior to enrollment, versus 41 controls matched for demographics, cardiovascular risk factors, concomitant treatment and angiographic/stent parameters. CLT, reflecting lysis of a tissue factor-induced plasma clot by exogenous tissue plasminogen activator, together with plasminogen activator inhibitor-1 (PAI-1) antigen and activity, thrombin-activatable fibrinolysis inhibitor (TAFI) antigen and activity, thrombomodulin (TM), plasminogen and α2-antiplasmin (α2AP) were measured. There were no inter-group differences in angiographic parameters, indication to the first PCI, culprit vessel or a type of stent. Patients with IST had 11% longer CLT (p=0.005) and 13% higher PAI-1 antigen (p=0.04) compared to controls. There were positive correlations in both groups between CLT and PAI-1 antigen and TAFI activity (all p<0.001). Multiple regression analysis showed that CLT (odds ratio [OR]=1.04 per 1 minute, 95% CI 1.01-1.08, p=0.02) and platelet count (OR=1.01 per 1,000/μl, 95% CI 1.00-1.02, p=0.034) were independent predictors of IST (R(2)=0.28, p<0.05). Concluding, impaired fibrinolytic potential, that is in part determined by plasma PAI-1 antigen and TAFI activity, characterises patients with a history of acute and subacute IST, which might help identify patients at higher risk of IST.     

Molecular epidemiology of hepatitis A outbreaks and sporadic cases,Latvia, 2017 to 2019

BackgroundHepatitis A is an acute infection of the liver caused by hepatitis A virus (HAV). Molecular detection and typing of the HAV VP1/P2A genomic region is used for genotyping and outbreak investigations. After a large hepatitis A outbreak in Latvia in 2007–08, only sporadic cases were registered until 2017 when a rise in cases occurred. During 2017–19, 179 laboratory-confirmed hepatitis A cases were notified in Latvia.AimTo investigate the observed increase in hepatitis A cases during 2017 and to determine whether these cases were linked to one another, to risk groups, or to other outbreaks. The majority of HAV samples (69.8%) were typed.MethodsThe VP1/P2A genomic region of HAV was amplified and sequenced for 125 case serum samples. Information about hepatitis-related symptoms, hospitalisation, vaccination, a possible source of infection and suspected countries of origin of the virus were analysed for sequenced cases.ResultsMost HAV strains were subgenotype IA (n = 77), of which 41 were strains circulating among men who have sex with men (MSM) populations in Europe (VRD_521_2016 (n = 32), RIVM-HAV16–090 (n = 7) or V16–25801 (n = 2)). Forty-four cases were subgenotype IB and four cases subgenotype IIIA. However, other clusters and sporadic cases were detected with or without identifying the epidemiological link.ConclusionThis work represents molecular epidemiological data of hepatitis A cases in Latvia from 2017 to 2019. Molecular typing methods allow identification of clusters for public health needs and establishing links with other outbreaks, and to compare Latvian strains with reported strains from other countries.     

Changing HCV genotypes distribution in Poland--relation to source and time of infection.

BACKGROUND: Understanding the distribution of HCV genotypes has implications for prognosis and therapy of hepatitis C. OBJECTIVES: To describe the distribution of HCV genotypes in Poland in relation to route of transmission and year of infection. STUDY DESIGN: Patients with chronic liver disease were evaluated at the Department of Infectious Diseases, Bialystok (Poland). HCV genotype was determined by means of 5'UTR sequencing and comparison with known sequences of particular genotypes. RESULTS: The genotypes mostly frequently detected were genotype 1 (57.5%); genotype 3 (31.3%); and genotype 4 (8.4%). Genotype 1 constituted the majority of HCV infections caused by blood transfusion (68.8%) and only 34.8% of HCV infections in the intravenous drug use (IVDU) group (p<0.05). In contrast genotype 3 constituted the majority of HCV infections in the IVDU group (56.5%). We observed a significant increase in the proportion of genotype 3 infections detected after 2000--from 19.1% to 38.9%. CONCLUSIONS: The relative proportion of genotype 1b in Poland has decreased and that of genotype 3a has increased, especially among IVDU.     

Maternal blood endotoxin activity in pregnancies complicated by preterm premature rupture of membranes

Objective: To compare maternal blood endotoxin activity (EA) in women with preterm premature rupture of membranes (PPROM) with gestational age (GA) matched controls; to evaluate serial EA till birth in PPROM and its correlation with latency to delivery.

Methods: We followed singleton preterm pregnancies from admission with PPROM until birth. Uncomplicated, GA-matched pregnancies served as controls. Demographics, birth and neonatal outcomes were collected. EA (EAA?) was assessed serially in PPROM and at study entry in controls. EA was compared using Mann Whitney and Wilcoxon tests, p value <.05 was considered significant.

Results: We recruited 20 cases of PPROM and 20 controls. Demographics were similar between groups. Mean GA of PPROM was 29.0?±?2.2 weeks and median latency was 7.5 (IQR 14.1) weeks. Median EA at admission following PPROM was significantly elevated over controls (0.43 (0.18) versus 0.36 (0.2); p?p?=?.2) following PPROM. However, on comparing cases with latency to delivery ≤7 days (n?=?10) versus >7 days (n?=?10), there was a significant drop in EA in the latter group (0.44 (0.2) versus 0.34 (0.2); p?相似文献   

Stable long-term blood formation by stem cells in murine steady-state hematopoiesis

Hematopoietic stem cells (HSCs) generate all mature blood cells during the whole lifespan of an individual. However, the clonal contribution of individual HSC and progenitor cells in steady-state hematopoiesis is poorly understood. To investigate the activity of HSCs under steady-state conditions, murine HSC and progenitor cells were genetically marked in vivo by integrating lentiviral vectors (LVs) encoding green fluorescent protein (GFP). Hematopoietic contribution of individual marked clones was monitored by determination of lentiviral integration sites using highly sensitive linear amplification-mediated-polymerase chain reaction. A remarkably stable small proportion of hematopoietic cells expressed GFP in LV-injected animals for up to 24 months, indicating stable marking of murine steady-state hematopoiesis. Analysis of the lentiviral integration sites revealed that multiple hematopoietic clones with both myeloid and lymphoid differentiation potential contributed to long-term hematopoiesis. In contrast to intrafemoral vector injection, intravenous administration of LV preferentially targeted short-lived progenitor cells. Myelosuppressive treatment of mice prior to LV-injection did not affect the marking efficiency. Our study represents the first continuous analysis of clonal behavior of genetically marked hematopoietic cells in an unmanipulated system, providing evidence that multiple clones are simultaneously active in murine steady-state hematopoiesis. Stem Cells2012;30:1961-1970.     

Mannose-binding lectin gene polymorphism, vulvovaginal candidiasis, and bacterial vaginosis

OBJECTIVE: To evaluate associations between polymorphisms in the gene coding for mannose-binding lectin (MBL) and the diagnosis of acute or recurrent vulvovaginal candidiasis and bacterial vaginosis METHODS: Women at two outpatient clinics in Brazil filled out a questionnaire and were examined for the presence of vulvovaginal candidiasis or bacterial vaginosis. A buccal swab was blindly tested for codons 54 and 57 MBL2 gene polymorphisms by polymerase chain reaction and endonuclease digestion. RESULTS: A total of 177 women were enrolled. Vulvovaginal candidiasis was identified in 78 (44.1%) women, 33 (18.6%) had bacterial vaginosis, and 66 (37.3%) were normal controls. Recurrent vulvovaginal candidiasis was present in 50 (64.1%) of the women with vulvovaginal candidiasis; 20 (60.6%) of the bacterial vaginosis patients had recurrent disease. Vulvovaginal candidiasis was associated with white race (P=.007), bacterial vaginosis was associated with nonwhite race (P=.05), and both were associated with a history of allergy (P< or =.02) and having sexual intercourse at least three times a week (P<.001). Carriage of the variant MBL2 codon 54 allele B was more frequent in women with recurrent vulvovaginal candidiasis (25.0%) than in the women with acute vulvovaginal candidiasis (17.9%) or controls (10.6%) (P=.004). Allele B was also more prevalent in women with recurrent bacterial vaginosis (22.5%) than in those with acute bacterial vaginosis (0%) (P=.009). The MBL2 codon 57 polymorphism was infrequent and not associated with vulvovaginal candidiasis or bacterial vaginosis. CONCLUSION: The incidence of vulvovaginal candidiasis and bacterial vaginosis differs by ethnicity in Brazilian women. The MBL2 codon 54 gene polymorphism is associated with both recurrent vulvovaginal candidiasis and recurrent bacterial vaginosis.     

Contributions of Different Spatial Modulations of Brightness Gradients to the Control of Visual Attention

Neuroscience and Behavioral Physiology - The targets of visual selective attention are the most informative parts of images. All new data in recent years have pointed to the importance of...