355 research outputs found

    A role for chromatin remodellers in replication of damaged DNA

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    In eukaryotic cells, replication past damaged sites in DNA is regulated by the ubiquitination of proliferating cell nuclear antigen (PCNA). Little is known about how this process is affected by chromatin structure. There are two isoforms of the Remodels the Structure of Chromatin (RSC) remodelling complex in yeast. We show that deletion of RSC2 results in a dramatic reduction in the level of PCNA ubiquitination after DNA-damaging treatments, whereas no such effect was observed after deletion of RSC1. Similarly, depletion of the BAF180 component of the corresponding PBAF (Polybromo BRG1 (Brahma-Related Gene 1) Associated Factor) complex in human cells led to a similar reduction in PCNA ubiquitination. Remarkably, we found that depletion of BAF180 resulted after UV-irradiation, in a reduction not only of ubiquitinated PCNA but also of chromatin-associated unmodified PCNA and Rad18 (the E3 ligase that ubiquitinates PCNA). This was accompanied by a modest decrease in fork progression. We propose a model to account for these findings that postulates an involvement of PBAF in repriming of replication downstream from replication forks blocked at sites of DNA damage. In support of this model, chromatin immunoprecipitation data show that the RSC complex in yeast is present in the vicinity of the replication forks, and by extrapolation, this is also likely to be the case for the PBAF complex in human cells

    New methods for the synthesis of certain alkaloids and terpenoids

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    The use of ring-fused gem-dihalocyclopropanes, Au(I)-catalyzed cyclization reactions, and chemoenzymatic techniques in the synthesis of natural products is described.We thank the Australian Research Council for generous financial support through the provision of various grants

    Accurate quantification of selenoproteins in human plasma/serum by isotope dilution ICP-MS : focus on selenoprotein P

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    Acknowledgements The research leading to these results was funded by the EMRP Joint Research Project “Metrology for metalloproteins” (HLT-05 2012). The EMRP is jointly funded by the EMRP participating countries within EURAMET and the European Union.Peer reviewedPostprin

    Patterns among Patients with Chronic Pruritus: A Retrospective Analysis of 170 Patients.

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    Chronic pruritus profoundly affects patients' quality of life. The objective of this retrospective cross-sectional study was to characterize patients with chronic pruritus and identify patterns, in order to delineate a better diagnostic approach. Both semantic connectivity map and classical analysis were applied, linking demographic, clinical, laboratory and histopathological data with clinical and aetiological categories of 170 patients with chronic pruritus (median age 72 years, 58.2% women). The semantic map showed clinical categories separated in different hubs associated with distinct patterns concerning sex, aetiology, laboratory findings, and pharmacological treatment. Diabetes, diagnosis of cancer and psychiatric comorbidities were linked with certain clinical categories. Skin eosinophilia was a common finding of chronic pruritus, on both diseased and non-diseased skin. High frequencies of patients with chronic pruritus taking anti-arrhythmics, beta-blockers and AT-II receptor antagonists were noticed among those with underlying systemic, neurological and psychiatric diseases. This study provides a complex analysis of chronic pruritus and thus basic principles for a clinical work-up

    HIV pre-exposure prophylaxis was associated with no impact on sexually transmitted infection prevalence in a high-prevalence population of predominantly men who have sex with men, Germany, 2018 to 2019

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    Introduction: Despite increased use of pre-exposure prophylaxis (PrEP) in Germany, HIV infection rates are not declining and little is known about how this prevention method affects the prevalence of sexually transmitted infections (STI) among men who have sex with men (MSM). Aim: We studied, in a large multicentre cohort, STI point prevalence, co-infection rates, anatomical location and influence of PrEP. Methods: The BRAHMS study was a prospective cohort study conducted at 10 sites in seven major German cities that enrolled MSM reporting increased sexual risk behaviour. At screening visits, MSM were tested for Mycoplasma genitalium (MG), Neisseria gonorrhoeae (NG), Chlamydia trachomatis (CT) and Treponema pallidum (TP), and given a behavioural questionnaire. With binomial regression, we estimated prevalence ratios (PR) and 95% confidence intervals (CI) for the association of PrEP and STI. Results: We screened 1,043 MSM in 2018 and 2019, with 53.0% currently using PrEP. At screening, 370 participants (35.5%) had an STI. The most common pathogen was MG in 198 (19.0%) participants, followed by CT (n = 133; 12.8%), NG (n = 105; 10.1%) and TP (n = 37; 3.5%). Among the 370 participants with at least one STI, 14.6% (n = 54) reported STI-related symptoms. Infection prevalence was highest at anorectal site (13.4% MG, 6.5% NG, 10.2% CT). PrEP use was not statistically significant in adjusted models for STI (PR: 1.10; 95% CI: 0.91–1.32), NG/CT, only NG or only CT. Conclusions: Prevalence of asymptomatic STI was high, and PrEP use did not influence STI prevalence in MSM eligible for PrEP according to national guidelines.Peer Reviewe

    Management of Suspected Cases of Feline Immunodeficiency Virus Infection in Eurasian Lynx (Lynx lynx) During an International Translocation Program.

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    The Eurasian lynx (Lynx lynx) population in Switzerland serves as a source for reintroductions in neighboring countries. In 2016-2017, three lynx from the same geographical area were found seropositive for feline immunodeficiency virus (FIV) in the framework of an international translocation program. This novel finding raised questions about the virus origin and pathogenicity to lynx, the emerging character of the infection, and the interpretation of serological results in other lynx caught for translocation. Archived serum samples from 84 lynx captured in 2001-2016 were retrospectively tested for FIV antibodies by Western blot. All archived samples were FIV-negative. The three seropositive lynx were monitored in quarantine enclosures prior to euthanasia and necropsy. They showed disease signs, pathological findings, and occurrence of co-infections reminding of those described in FIV-infected domestic cats. All attempts to isolate and characterize the virus failed but serological data and spatiotemporal proximity of the cases suggested emergence of a lentivirus with antigenic and pathogenic similarities to FIV in the Swiss lynx population. A decision scheme was developed to minimize potential health risks posed by FIV infection, both in the recipient and source lynx populations, considering conservation goals, animal welfare, and the limited action range resulting from local human conflicts. Development and implementation of a cautious decision scheme was particularly challenging because FIV pathogenic potential in lynx was unclear, negative FIV serological results obtained within the first weeks after infection are unpredictable, and neither euthanasia nor repatriation of multiple lynx was acceptable options. The proposed scheme distinguished between three scenarios: release at the capture site, translocation, or euthanasia. Until April 2021, none of the 40 lynx newly captured in Switzerland tested FIV-seropositive. Altogether, seropositivity to FIV was documented in none of 124 lynx tested at their first capture, but three of them seroconverted in 2016-2017. Diagnosis of FIV infection in the three seropositive lynx remains uncertain, but clinical observations and pathological findings confirmed that euthanasia was appropriate. Our experiences underline the necessity to include FIV in pathogen screenings of free-ranging European wild felids, the importance of lynx health monitoring, and the usefulness of health protocols in wildlife translocation

    Isolation of a wide range of minerals from a thermally treated plant: Equisetum arvense, a Mare’s tale

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    Silica is the second most abundant biomineral being exceeded in nature only by biogenic CaCO3. Many land plants (such as rice, cereals, cucumber, etc.) deposit silica in significant amounts to reinforce their tissues and as a systematic response to pathogen attack. One of the most ancient species of living vascular plants, Equisetum arvense is also able to take up and accumulate silica in all parts of the plant. Numerous methods have been developed for elimination of the organic material and/or metal ions present in plant material to isolate biogenic silica. However, depending on the chemical and/or physical treatment applied to branch or stem from Equisetum arvense; other mineral forms such glass-type materials (i.e. CaSiO3), salts (i.e. KCl) or luminescent materials can also be isolated from the plant material. In the current contribution, we show the chemical and/or thermal routes that lead to the formation of a number of different mineral types in addition to biogenic silica

    Clonal Hematopoiesis and Blood-Cancer Risk Inferred from Blood DNA Sequence

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    Background Cancers arise from multiple acquired mutations, which presumably occur over many years. Early stages in cancer development might be present years before cancers become clinically apparent. Methods We analyzed data from whole-exome sequencing of DNA in peripheral-blood cells from 12,380 persons, unselected for cancer or hematologic phenotypes. We identified somatic mutations on the basis of unusual allelic fractions. We used data from Swedish national patient registers to follow health outcomes for 2 to 7 years after DNA sampling. Results Clonal hematopoiesis with somatic mutations was observed in 10% of persons older than 65 years of age but in only 1% of those younger than 50 years of age. Detectable clonal expansions most frequently involved somatic mutations in three genes (DNMT3A, ASXL1, and TET2) that have previously been implicated in hematologic cancers. Clonal hematopoiesis was a strong risk factor for subsequent hematologic cancer (hazard ratio, 12.9; 95% confidence interval, 5.8 to 28.7). Approximately 42% of hematologic cancers in this cohort arose in persons who had clonality at the time of DNA sampling, more than 6 months before a first diagnosis of cancer. Analysis of bone marrow–biopsy specimens obtained from two patients at the time of diagnosis of acute myeloid leukemia revealed that their cancers arose from the earlier clones. Conclusions Clonal hematopoiesis with somatic mutations is readily detected by means of DNA sequencing, is increasingly common as people age, and is associated with increased risks of hematologic cancer and death. A subset of the genes that are mutated in patients with myeloid cancers is frequently mutated in apparently healthy persons; these mutations may represent characteristic early events in the development of hematologic cancers. (Funded by the National Human Genome Research Institute and others.)National Human Genome Research Institute (U.S.) (Grant U54 HG003067)National Human Genome Research Institute (U.S.) (Grant R01 HG006855)Stanley Center for Psychiatric ResearchAlexander and Margaret Stewart TrustNational Institute of Mental Health (U.S.) (Grant R01 MH 077139)National Institute of Mental Health (U.S.) (Grant RC2 MH089905)Sylvan C. Herman Foundatio

    Vitamin D supplementation and breast cancer prevention : a systematic review and meta-analysis of randomized clinical trials

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    In recent years, the scientific evidence linking vitamin D status or supplementation to breast cancer has grown notably. To investigate the role of vitamin D supplementation on breast cancer incidence, we conducted a systematic review and meta-analysis of randomized controlled trials comparing vitamin D with placebo or no treatment. We used OVID to search MEDLINE (R), EMBASE and CENTRAL until April 2012. We screened the reference lists of included studies and used the “Related Article” feature in PubMed to identify additional articles. No language restrictions were applied. Two reviewers independently extracted data on methodological quality, participants, intervention, comparison and outcomes. Risk Ratios and 95% Confident Intervals for breast cancer were pooled using a random-effects model. Heterogeneity was assessed using the I2 test. In sensitivity analysis, we assessed the impact of vitamin D dosage and mode of administration on treatment effects. Only two randomized controlled trials fulfilled the pre-set inclusion criteria. The pooled analysis included 5372 postmenopausal women. Overall, Risk Ratios and 95% Confident Intervals were 1.11 and 0.74–1.68. We found no evidence of heterogeneity. Neither vitamin D dosage nor mode of administration significantly affected breast cancer risk. However, treatment efficacy was somewhat greater when vitamin D was administered at the highest dosage and in combination with calcium (Risk Ratio 0.58, 95% Confident Interval 0.23–1.47 and Risk Ratio 0.93, 95% Confident Interval 0.54–1.60, respectively). In conclusions, vitamin D use seems not to be associated with a reduced risk of breast cancer development in postmenopausal women. However, the available evidence is still limited and inadequate to draw firm conclusions. Study protocol code: FARM8L2B5L

    Promoting More Physical Activity and Less Sedentary Behaviour During the COVID-19 Situation – SportStudisMoveYou (SSMY): A Randomized Controlled Trial

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    Objective: To determine the effect of an innovative, online-based intervention, addressing the possible decline of physical activity (PA) and increase of sedentary behavior (SB) during COVID-19 stay at home restrictions in Switzerland. Methods: This study investigated the effect of a two-week, social cognitive theory based, online-video moderate to vigorous (MV)PA or SB intervention on MVPA and SB behaviour and intention via a 3 group by 2 time point parallel randomized controlled trial during the COVID-19 pandemic. Adults (≥18 yo) were recruited over the internet between April 10th and April 19th 2020 (n = 129; 75.2% female; mean age = 29.0 [SD 11.8] years). Both intervention groups received five videos targeting either SB for the SB group or MVPA for the MVPA group and were compared to an attention control group (fruit and vegetable consumption). It was hypothesized that MVPA time and intention would increase for the MVPA group and the SB group would outperform control on SB behaviour and intention indicators. Results: No significant interactions were found for the MVPA group (n = 41) versus control (n = 40). Only one significant interaction was measured for the SB group (n = 48; intention of active breaks F = (2,114) = 5.84, p = 0.004, ηp2 = 0.09). Although mostly non-significant and small effects, the MVPA group showed results pointing in the hypothesized direction on all PA indicators and the SB on all SB indicators, respectively. Conclusion: Considering this study’s limitations (e.g. small intervention dose), video-based online PA and SB interventions seem promising and feasible. This approach is appropriate for COVID-19 and other stay at home situations
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