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31.
Klaus Jansen Michael Thamm Claus-Thomas Bock Ramona Scheufele Claudia Kücherer Dieter Muenstermann Hans-Jochen Hagedorn Heiko Jessen Stephan Dupke Osamah Hamouda Barbara Gunsenheimer-Bartmeyer Karolin Meixenberger HIV Seroconverter Study Group 《PloS one》2015,10(11)
Objectives
Men who have sex with men (MSM) are at higher risk for coinfection with hepatitis B virus (HBV), hepatitis C virus (HCV), and syphilis than the general population. HIV infection and these coinfections accelerate disease progression reciprocally. This study evaluated the prevalence and incidence of these coinfections in HIV1-positive MSM in Germany.Materials and Methods
As part of a nationwide, multicenter, prospective cohort study of HIV-infected MSM, plasma samples collected yearly were screened for HBsAg and antibodies to HBc, HBs, HCV, and syphilis. Samples with indications of active HBV or HCV infection were confirmed by polymerase chain reaction. Prevalence and incidence of each infection and incidence rates per study participant were calculated, and incidences over 4-year time intervals compared.Results
This study screened 5,445 samples from 1,843 MSM. Median age at HIV seroconversion was 33 years. Prevalences of active, cleared, and occult HBV, and of active/cleared HCV were 1.7%, 27.1%, 0.2%, and 8.2%, respectively, and 47.5% had been effectively vaccinated against HBV. Prevalence of antibodies to Treponema pallidum and of triple or quadruple sexually transmitted infections (STIs) were 39.6% and 18.9%, respectively. Prevalence of STI, cleared HBV, HBV vaccination, and history of syphilis differed significantly among age groups. Incidences of HBV, HCV, and syphilis were 2.51, 1.54, and 4.06 per 100 person-years, respectively. Incidences of HCV and syphilis increased over time. HCV incidence was significantly higher in MSM coinfected with syphilis and living in Berlin, and syphilis incidence was significantly higher for MSM living in Berlin.Discussion
Despite extensive HBV vaccination campaigns, fewer than 50% of screened MSM were effectively vaccinated, with a high proportion of HIV-positive MSM coinfected with HBV. High rates of STI coinfections in HIV-positive MSM and increasing incidences emphasize the need for better tailored campaigns for HBV vaccination and STI prevention. 相似文献32.
Marie Spohn Karolin Müller Carmen Hschen Carsten W. Mueller Sven Marhan 《Global Change Biology》2020,26(3):1926-1935
Dark, that is, nonphototrophic, microbial CO2 fixation occurs in a large range of soils. However, it is still not known whether dark microbial CO2 fixation substantially contributes to the C balance of soils and what factors control this process. Therefore, the objective of this study was to quantitate dark microbial CO2 fixation in temperate forest soils, to determine the relationship between the soil CO2 concentration and dark microbial CO2 fixation, and to estimate the relative contribution of different microbial groups to dark CO2 fixation. For this purpose, we conducted a 13C‐CO2 labeling experiment. We found that the rates of dark microbial CO2 fixation were positively correlated with the CO2 concentration in all soils. Dark microbial CO2 fixation amounted to up to 320 µg C kg?1 soil day?1 in the Ah horizon. The fixation rates were 2.8–8.9 times higher in the Ah horizon than in the Bw1 horizon. Although the rates of dark microbial fixation were small compared to the respiration rate (1.2%–3.9% of the respiration rate), our findings suggest that organic matter formed by microorganisms from CO2 contributes to the soil organic matter pool, especially given that microbial detritus is more stable in soil than plant detritus. Phospholipid fatty acid analyses indicated that CO2 was mostly fixed by gram‐positive bacteria, and not by fungi. In conclusion, our study shows that the dark microbial CO2 fixation rate in temperate forest soils increases in periods of high CO2 concentrations, that dark microbial CO2 fixation is mostly accomplished by gram‐positive bacteria, and that dark microbial CO2 fixation contributes to the formation of soil organic matter. 相似文献
33.
Daniel Schmidt Christian Kollan Gerd F?tkenheuer Eugen Schülter Hans-Jürgen Stellbrink Christian Noah Bj?rn-Erik Ole Jensen Matthias Stoll Johannes R. Bogner Josef Eberle Karolin Meixenberger Claudia Kücherer Osamah Hamouda Barbara Bartmeyer 《PloS one》2014,9(8)
Objective
We assessed trends in the proportion of transmitted (TDR) and acquired (ADR) HIV drug resistance and associated mutations between 2001 and 2011 in the German ClinSurv-HIV Drug Resistance Study.Method
The German ClinSurv-HIV Drug Resistance Study is a subset of the German ClinSurv-HIV Cohort. For the ClinSurv-HIV Drug Resistance Study all available sequences isolated from patients in five study centres of the long term observational ClinSurv-HIV Cohort were included. TDR was estimated using the first viral sequence of antiretroviral treatment (ART) naïve patients. One HIV sequence/patient/year of ART experienced patients was considered to estimate the proportion of ADR. Trends in the proportion of HIV drug resistance were calculated by logistic regression.Results
9,528 patients were included into the analysis. HIV-sequences of antiretroviral naïve and treatment experienced patients were available from 34% (3,267/9,528) of patients. The proportion of TDR over time was stable at 10.4% (95% CI 9.1–11.8; p for trend = 0.6; 2001–2011). The proportion of ADR among all treated patients was 16%, whereas it was high among those with available HIV genotypic resistance test (64%; 1,310/2,049 sequences; 95% CI 62–66) but declined significantly over time (OR 0.8; 95% CI 0.77–0.83; p for trend<0.001; 2001–2011). Viral load monitoring subsequent to resistance testing was performed in the majority of treated patients (96%) and most of them (67%) were treated successfully.Conclusions
The proportion of TDR was stable in this study population. ADR declined significantly over time. This decline might have been influenced by broader resistance testing, resistance test guided therapy and the availability of more therapeutic options and not by a decline in the proportion of TDR within the study population. 相似文献34.
35.
RecA protein and its eukaryotic homologue Rad51 protein catalyzes the DNA strand exchange, which is a key reaction of homologous recombination. At the initial step of the reaction, RecA proteins form a helical filament on a single-stranded DNA (ssDNA). Binding of double-stranded DNA (dsDNA) to the filament triggers the homology search; as homology is found, the exchange of strands occurs, and the displaced DNA is released. These are the principal steps of genetic recombination; however, despite many years of extensive study of RecA activities, the details of the mechanism are still obscure. A high-resolution structure of the active nucleoprotein filament could provide information to help understand this process. Using a linear dichroism polarized-light spectroscopy technique, in combination with protein engineering (the site-specific linear dichroism method), we have previously studied the arrangement of RecA in complex with ssDNA. In the present study, we have used this approach to search for structural variations of RecA at the atomic level as the DNA in the complex is changed from ssDNA to dsDNA. The structural data of the RecA-dsDNA filament are found to be very similar to the data previously obtained for the RecA-ssDNA complex, indicating that the overall orientation and also the internal structure of RecA in the active filament are not markedly altered when the bound DNA changes from single- to double-stranded. The implications of the structural similarities as well as the significance of some conformational variations observed for a few amino acid residues that may be involved in interactions with DNA are discussed. 相似文献
36.
Background
Violence against Women –despite its perpetuation over centuries and its omnipresence at all social levels– entered into social consciousness and the general agenda of Social Sciences only recently, mainly thanks to feminist research, campaigns, and general social awareness. The present article analyzes in a secondary analysis of German prevalence data on Violence against Women, whether the frequency and severity of Violence against Women can be described with power laws.Principal Findings
Although the investigated distributions all resemble power-law distributions, a rigorous statistical analysis accepts this hypothesis at a significance level of 0.1 only for 1 of 5 cases of the tested frequency distributions and with some restrictions for the severity of physical violence. Lowering the significance level to 0.01 leads to the acceptance of the power-law hypothesis in 2 of the 5 tested frequency distributions and as well for the severity of domestic violence. The rejections might be mainly due to the noise in the data, with biases caused by self-reporting, errors through rounding, desirability response bias, and selection bias.Conclusion
Future victimological surveys should be designed explicitly to avoid these deficiencies in the data to be able to clearly answer the question whether Violence against Women follows a power-law pattern. This finding would not only have statistical implications for the processing and presentation of the data, but also groundbreaking consequences on the general understanding of Violence against Women and policy modeling, as the skewed nature of the underlying distributions makes evident that Violence against Women is a highly disparate and unequal social problem. This opens new questions for interdisciplinary research, regarding the interplay between environmental, experimental, and social factors on victimization. 相似文献37.
38.
In order to understand biotic patterns and their changes in nature there is an obvious need for high-quality seamless measurements of such patterns. If remote sensing methods have been applied with reasonable success in terrestrial environment, their use in aquatic ecosystems still remained challenging. In the present study we combined hyperspectral remote sensing and boosted regression tree modelling (BTR), an ensemble method for statistical techniques and machine learning, in order to test their applicability in predicting macrophyte and invertebrate species cover in the optically complex seawater of the Baltic Sea. The BRT technique combined with remote sensing and traditional spatial modelling succeeded in identifying, constructing and testing functionality of abiotic environmental predictors on the coverage of benthic macrophyte and invertebrate species. Our models easily predicted a large quantity of macrophyte and invertebrate species cover and recaptured multitude of interactions between environment and biota indicating a strong potential of the method in the modelling of aquatic species in the large variety of ecosystems. 相似文献
39.
40.
Thiel CS Paulsen K Bradacs G Lust K Tauber S Dumrese C Hilliger A Schoppmann K Biskup J Gölz N Sang C Ziegler U Grote KH Zipp F Zhuang F Engelmann F Hemmersbach R Cogoli A Ullrich O 《Cell communication and signaling : CCS》2012,10(1):1-16
ABSTRACT: In our study we aimed to identify rapidly reacting gravity-responsive mechanisms in mammalian cells in order to understand if and how altered gravity is translated into a cellular response. In a combination of experiments using "functional weightlessness" provided by 2D-clinostats and real microgravity provided by several parabolic flight campaigns and compared to in-flight-1g-controls, we identified rapid gravity-responsive reactions inside the cell cycle regulatory machinery of human T lymphocytes. In response to 2D clinorotation, we detected an enhanced expression of p21 Waf1/Cip1 protein within minutes, less cdc25C protein expression and enhanced Ser147-phosphorylation of cyclinB1 after CD3/CD28 stimulation. Additionally, during 2D clinorotation, Tyr-15-phosphorylation occurred later and was shorter than in the 1 g controls. In CD3/CD28-stimulated primary human T cells, mRNA expression of the cell cycle arrest protein p21 increased 4.1-fold after 20s real microgravity in primary CD4+ T cells and 2.9-fold in Jurkat T cells, compared to 1 g in-flight controls after CD3/CD28 stimulation. The histone acetyltransferase (HAT) inhibitor curcumin was able to abrogate microgravity-induced p21 mRNA expression, whereas expression was enhanced by a histone deacetylase (HDAC) inhibitor. Therefore, we suppose that cell cycle progression in human T lymphocytes requires Earth gravity and that the disturbed expression of cell cycle regulatory proteins could contribute to the breakdown of the human immune system in space. 相似文献