378 research outputs found

    Dynamic Micropatterning Reveals Substrate-Dependent Differences in the Geometric Control of Cell Polarization and Migration

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    Cells are highly dynamic and adopt variable shapes and sizes. These variations are biologically important but challenging to investigate in a spatiotemporally controlled manner. Micropatterning, confining cells on microfabricated substrates with defined geometries and molecular compositions, is a powerful tool for controlling cell shape and interactions. However, conventional binary micropatterns are static and fail to address dynamic changes in cell polarity, spreading, and migration. Here, a method for dynamic micropatterning is reported, where the non-adhesive surface surrounding adhesive micropatterns is rapidly converted to support specific cell-matrix interactions while allowing simultaneous imaging of the cells. The technique is based on ultraviolet photopatterning of biotinylated polyethylene glycol-grafted poly-L-lysine, and it is simple, inexpensive, and compatible with a wide range of streptavidin-conjugated ligands. Experiments using biotinylation-based dynamic micropatterns reveal that distinct extracellular matrix ligands and bivalent integrin-clustering antibodies support different degrees of front-rear polarity in human glioblastoma cells, which correlates to altered directionality and persistence upon release and migration on fibronectin. Unexpectedly, however, neither an asymmetric cell shape nor centrosome orientation can fully predict the future direction of migration. Taken together, biotinylation-based dynamic micropatterns allow easily accessible and highly customizable control over cell morphology and motility

    First Observation of a Spontaneously Matured Female European Eel (Anguilla anguilla)

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    This study reports on the first observation of a spontaneously matured female European eel. The 43-year-old eel, together with eleven other females, resided at an aquarium house since their capture in 2002 and stocking as glass eels in 1978. In June 2019, the girth of the belly of the female increased as a sign of oocyte maturation. The specimen had an estimated gonadosomatic index (GSI) of 47, only half of the oocytes were hydrated and matured, indicating that European eels are polycyclic batch spawners. The live eels of the cohort were still in the previtellogenic phase but their eye sizes were close to that of the matured eel. We hypothesize that substances released by other maturing and spawning fishes may have triggered puberty of the eel. This first observation, and the possibility of more eels maturing in the near future, provides a natural reference for the sexual maturation of the European eel.</p

    Suppressed bone turnover in obesity: a link to energy metabolism? A case-control study

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    CONTEXT\nObservations in rodents suggest that osteocalcin (OC) participates in glucose metabolism. Based on human studies, it remains unclear whether circulating OC is simply a bone turnover marker (BTM) or also a mediator in interactions between the skeleton and glucose homeostasis.\nOBJECTIVE\nThe objective of the study was to determine the responses of BTMs, including OC, to oral glucose tolerance test (OGTT) in a case-control setting.\nDESIGN AND PATIENTS\nThirty-four normoglycemic young adults [mean age 19 y (SD 2.3)] with severe childhood-onset obesity and their gender- and age-matched nonobese controls underwent a standard 2-hour OGTT.\nMAIN OUTCOME MEASURES\nGlucose, insulin, and six BTMs including total and carboxylated OC (cOC) were determined at baseline and at 30, 60, 90, and 120 minutes during OGTT.\nRESULTS\nThe obese and control subjects were similar in height; the mean body mass indices were 40.4 and 21.9 kg/m(2), respectively. The homeostasis model assessment index was 2.7 times greater in the obese subjects. All BTMs, except bone-specific alkaline phophatase, were lower in the obese subjects compared with the controls: the differences at baseline were 40%, 35%, 17%, 31%, and 32% for N-terminal propeptides of type I collagen, cross-linked telopeptides of type I collagen, tartrate-resistant acid phosphatase, total OC, and carboxylated OC (P &lt; .05 for all) after adjusting for whole-body bone area. All BTMs decreased during OGTT. The relative values for the OGTT responses for total, but not for cOC (measured as area under the curve) differed between the two groups (P = .029 and P = .139, respectively): the decrease in total OC during the OGTT was less pronounced in the obese subjects. Responses in other BTMs were similar between the groups. No associations were observed between glucose metabolism and OCs during OGTT with linear regression.\nCONCLUSIONS\nBone turnover markers were substantially lower in obese subjects compared with controls. Total OC and cOC showed less pronounced decrease during the OGTT in obese subjects compared with controls, whereas other BTMs responded similarly in the two groups. The role of OC, if anything, in glucose homeostasis is indirect and may be mediated via other factors than glucose or insulin.</p

    Fatal Outcome in Bacteremia is Characterized by High Plasma Cell Free DNA Concentration and Apoptotic DNA Fragmentation: A Prospective Cohort Study

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    INTRODUCTION: Recent studies have shown that apoptosis plays a critical role in the pathogenesis of sepsis. High plasma cell free DNA (cf-DNA) concentrations have been shown to be associated with sepsis outcome. The origin of cf-DNA is unclear. METHODS: Total plasma cf-DNA was quantified directly in plasma and the amplifiable cf-DNA assessed using quantitative PCR in 132 patients with bacteremia caused by Staphylococcus aureus, Streptococcus pneumoniae, ß-hemolytic streptococcae or Escherichia coli. The quality of cf-DNA was analyzed with a DNA Chip assay performed on 8 survivors and 8 nonsurvivors. Values were measured on days 1-4 after positive blood culture, on day 5-17 and on recovery. RESULTS: The maximum cf-DNA values on days 1-4 (n = 132) were markedly higher in nonsurvivors compared to survivors (2.03 vs 1.26 ug/ml, p<0.001) and the AUCROC in the prediction of case fatality was 0.81 (95% CI 0.69-0.94). cf-DNA at a cut-off level of 1.52 ug/ml showed 83% sensitivity and 79% specificity for fatal disease. High cf-DNA (>1.52 ug/ml) remained an independent risk factor for case fatality in a logistic regression model. Qualitative analysis of cf-DNA showed that cf-DNA displayed a predominating low-molecular-weight cf-DNA band (150-200 bp) in nonsurvivors, corresponding to the size of the apoptotic nucleosomal DNA. cf-DNA concentration showed a significant positive correlation with visually graded apoptotic band intensity (R = 0.822, p<0.001). CONCLUSIONS: Plasma cf-DNA concentration proved to be a specific independent prognostic biomarker in bacteremia. cf-DNA displayed a predominating low-molecular-weight cf-DNA band in nonsurvivors corresponding to the size of apoptotic nucleosomal DNA

    The incidence of liver injury in Uyghur patients treated for TB in Xinjiang Uyghur autonomous region, China, and its association with hepatic enzyme polymorphisms nat2, cyp2e1, gstm1 and gstt1.

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    BACKGROUND AND OBJECTIVE: Of three first-line anti-tuberculosis (anti-TB) drugs, isoniazid is most commonly associated with hepatotoxicity. Differences in INH-induced toxicity have been attributed to genetic variability at several loci, NAT2, CYP2E1, GSTM1and GSTT1, that code for drug-metabolizing enzymes. This study evaluated whether the polymorphisms in these enzymes were associated with an increased risk of anti-TB drug-induced hepatitis in patients and could potentially be used to identify patients at risk of liver injury. METHODS AND DESIGN: In a cross-sectional study, 2244 tuberculosis patients were assessed two months after the start of treatment. Anti-TB drug-induced liver injury (ATLI) was defined as an ALT, AST or bilirubin value more than twice the upper limit of normal. NAT2, CYP2E1, GSTM1 and GSTT1 genotypes were determined using the PCR/ligase detection reaction assays. RESULTS: 2244 patients were evaluated, there were 89 cases of ATLI, a prevalence of 4% 9 patients (0.4%) had ALT levels more than 5 times the upper limit of normal. The prevalence of ATLI was greater among men than women, and there was a weak association with NAT2*5 genotypes, with ATLI more common among patients with the NAT2*5*CT genotype. The sensitivity of the CT genotype for identifying patients with ATLI was 42% and the positive predictive value 5.9%. CT ATLI was more common among slow acetylators (prevalence ratio 2.0 (95% CI 0.95,4.20) )compared to rapid acetylators. There was no evidence that ATLI was associated with CYP2E1 RsaIc1/c1genotype, CYP2E1 RsaIc1/c2 or c2/c2 genotypes, or GSTM1/GSTT1 null genotypes. CONCLUSIONS: In Xinjiang Uyghur TB patients, liver injury was associated with the genetic variant NAT2*5, however the genetic markers studied are unlikely to be useful for screening patients due to the low sensitivity and low positive predictive values for identifying persons at risk of liver injury

    Multiple marker abundance profiling:combining selected reaction monitoring and data-dependent acquisition for rapid estimation of organelle abundance in subcellular samples

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    Measuring changes in protein or organelle abundance in the cell is an essential, but challenging aspect of cell biology. Frequently-used methods for determining organelle abundance typically rely on detection of a very few marker proteins, so are unsatisfactory. In silico estimates of protein abundances from publicly available protein spectra can provide useful standard abundance values but contain only data from tissue proteomes, and are not coupled to organelle localization data. A new protein abundance score, the normalized protein abundance scale (NPAS), expands on the number of scored proteins and the scoring accuracy of lower-abundance proteins in Arabidopsis. NPAS was combined with subcellular protein localization data, facilitating quantitative estimations of organelle abundance during routine experimental procedures. A suite of targeted proteomics markers for subcellular compartment markers was developed, enabling independent verification of in silico estimates for relative organelle abundance. Estimation of relative organelle abundance was found to be reproducible and consistent over a range of tissues and growth conditions. In silico abundance estimations and localization data have been combined into an online tool, multiple marker abundance profiling, available in the SUBA4 toolbox (http://suba.live)

    Liver Enzyme Abnormalities and Associated Risk Factors in HIV Patients on Efavirenz-Based HAART with or without Tuberculosis Co-Infection in Tanzania.

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    To investigate the timing, incidence, clinical presentation, pharmacokinetics and pharmacogenetic predictors for antiretroviral and anti-tuberculosis drug induced liver injury (DILI) in HIV patients with or without TB co-infection. A total of 473 treatment naïve HIV patients (253 HIV only and 220 with HIV-TB co-infection) were enrolled prospectively. Plasma efavirenz concentration and CYP2B6*6, CYP3A5*3, *6 and *7, ABCB1 3435C/T and SLCO1B1 genotypes were determined. Demographic, clinical and laboratory data were collected at baseline and up to 48 weeks of antiretroviral therapy. DILI case definition was according to Council for International Organizations of Medical Sciences (CIOMS). Incidence of DILI and identification of predictors was evaluated using Cox Proportional Hazards Model. The overall incidence of DILI was 7.8% (8.3 per 1000 person-week), being non-significantly higher among patients receiving concomitant anti-TB and HAART (10.0%, 10.7 per 1000 person-week) than those receiving HAART alone (5.9%, 6.3 per 1000 person-week). Frequency of CYP2B6*6 allele (p = 0.03) and CYP2B6*6/*6 genotype (p = 0.06) was significantly higher in patients with DILI than those without. Multivariate cox regression model indicated that CYP2B6*6/*6 genotype and anti-HCV IgG antibody positive as significant predictors of DILI. Median time to DILI was 2 weeks after HAART initiation and no DILI onset was observed after 12 weeks. No severe DILI was seen and the gain in CD4 was similar in patients with or without DILI. Antiretroviral and anti-tuberculosis DILI does occur in our setting, presenting early following HAART initiation. DILI seen is mild, transient and may not require treatment interruption. There is good tolerance to HAART and anti-TB with similar immunological outcomes. Genetic make-up mainly CYP2B6 genotype influences the development of efavirenz based HAART liver injury in Tanzanians

    Enhancing implementation of tobacco use prevention and cessation counselling guideline among dental providers: a cluster randomised controlled trial

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    Background: Tobacco use adversely affects oral health. Tobacco use prevention and cessation (TUPAC) counselling guidelines recommend that healthcare providers ask about each patient's tobacco use, assess the patient's readiness and willingness to stop, document tobacco use habits, advise the patient to stop, assist and help in quitting, and arrange monitoring of progress at follow-up appointments. Adherence to such guidelines, especially among dental providers, is poor. To improve guideline implementation, it is essential to understand factors influencing it and find effective ways to influence those factors. The aim of the present study protocol is to introduce a theory-based approach to diagnose implementation difficulties of TUPAC counselling guidelines among dental providers.Methods: Theories of behaviour change have been used to identify key theoretical domains relevant to the behaviours of healthcare providers involved in implementing clinical guidelines. These theoretical domains will inform the development of a questionnaire aimed at assessing the implementation of the TUPAC counselling guidelines among Finnish municipal dental providers. Specific items will be drawn from the guidelines and the literature on TUPAC studies. After identifying potential implementation difficulties, we will design two interventions using theories of behaviour change to link them with relevant behaviour change techniques aiming to improve guideline adherence. For assessing the implementation of TUPAC guidelines, the electronic dental record audit and self-reported questionnaires will be used.Discussion: To improve guideline adherence, the theoretical-domains approach could provide a comprehensive basis for assessing implementation difficulties, as well as designing and evaluating interventions. After having identified implementation difficulties, we will design and test two interventions to enhance TUPAC guideline adherence. Using the cluster randomised controlled design, we aim to provide further evidence on intervention effects, as well as on the validity and feasibility of the theoretical-domain approach. The empirical data collected within this trial will be useful in testing whether this theoretical-domain approach can improve our understanding of the implementation of TUPAC guidelines among dental providers
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