864 research outputs found
Murine norovirus infection does not cause major disruptions in the murine intestinal microbiota
BACKGROUND: Murine norovirus (MNV) is the most common gastrointestinal pathogen of research mice and can alter research outcomes in biomedical mouse models of inflammatory bowel disease (IBD). Despite indications that an altered microbiota is a risk factor for IBD, the response of the murine intestinal microbiota to MNV infection has not been examined. Microbiota disruption caused by MNV infection could introduce the confounding effects observed in research experiments. Therefore, this study investigated the effects of MNV infection on the intestinal microbiota of wild-type mice. RESULTS: The composition of the intestinal microbiota was assessed over time in both outbred Swiss Webster and inbred C57BL/6 mice following MNV infection. Mice were infected with both persistent and non-persistent MNV strains and tissue-associated or fecal-associated microbiota was analyzed by 16S rRNA-encoding gene pyrosequencing. Analysis of intestinal bacterial communities in infected mice at the phylum and family level showed no major differences to uninfected controls, both in tissue-associated samples and feces, and also over time following infection, demonstrating that the intestinal microbiota of wild-type mice is highly resistant to disruption following MNV infection. CONCLUSIONS: This is the first study to describe the intestinal microbiota following MNV infection and demonstrates that acute or persistent MNV infection is not associated with major disruptions of microbial communities in Swiss Webster and C57BL/6 mice
Murine norovirus infection does not cause major disruptions in the murine intestinal microbiota
Abstract
Background
Murine norovirus (MNV) is the most common gastrointestinal pathogen of research mice and can alter research outcomes in biomedical mouse models of inflammatory bowel disease (IBD). Despite indications that an altered microbiota is a risk factor for IBD, the response of the murine intestinal microbiota to MNV infection has not been examined. Microbiota disruption caused by MNV infection could introduce the confounding effects observed in research experiments. Therefore, this study investigated the effects of MNV infection on the intestinal microbiota of wild-type mice.
Results
The composition of the intestinal microbiota was assessed over time in both outbred Swiss Webster and inbred C57BL/6 mice following MNV infection. Mice were infected with both persistent and non-persistent MNV strains and tissue-associated or fecal-associated microbiota was analyzed by 16S rRNA-encoding gene pyrosequencing. Analysis of intestinal bacterial communities in infected mice at the phylum and family level showed no major differences to uninfected controls, both in tissue-associated samples and feces, and also over time following infection, demonstrating that the intestinal microbiota of wild-type mice is highly resistant to disruption following MNV infection.
Conclusions
This is the first study to describe the intestinal microbiota following MNV infection and demonstrates that acute or persistent MNV infection is not associated with major disruptions of microbial communities in Swiss Webster and C57BL/6 mice.http://deepblue.lib.umich.edu/bitstream/2027.42/112329/1/40168_2012_Article_7.pd
Successful weight loss maintenance in relation to method of weight loss
This study examined the relation between method of weight loss and long-term maintenance among successful weight losers enrolled in a weight-loss maintenance trial. Participants were 186 adults (mean age = 51.6 +/- 10.7 years, mean BMI = 28.6 +/- 4.7 kg/m(2)) enrolled in the STOP Regain trial who had lost at least 10% of their body weight in the past 2 years using a very low-calorie diet (VLCD; n = 24), commercial program (n = 95), or self-guided approach (n = 67). Participants were randomized to a weight-maintenance intervention delivered face to face or over the internet or to a newsletter control condition, and followed for 18 months. At study entry, individuals who had used a VLCD had achieved a weight loss of 24% of their maximum weight within the past 2 years compared to 17% achieved by those who had used a commercial program or self-guided approach (P \u3c 0.001). However, individuals who had used a VLCD regained significantly more weight than the other two groups and by 6 months, there were no significant differences in overall percent weight loss (i.e., initial weight loss and maintenance) between VLCD, commercial, and self-guided methods. In contrast, individuals who had used a self-guided approach maintained their weight losses from baseline through 18 months. The large initial weight losses achieved by individuals who had used a VLCD were not maintained over time, whereas individuals who had used a self-guided approach maintained their initial weight losses with the greatest success. The generalizability of these findings is limited by the sizeable weight losses achieved by study participants
Workgroup Report: Workshop on Source Apportionment of Particulate Matter Health Effects—Intercomparison of Results and Implications
Although the association between exposure to ambient fine particulate matter with aerodynamic diameter < 2.5 μm (PM(2.5)) and human mortality is well established, the most responsible particle types/sources are not yet certain. In May 2003, the U.S. Environmental Protection Agency’s Particulate Matter Centers Program sponsored the Workshop on the Source Apportionment of PM Health Effects. The goal was to evaluate the consistency of the various source apportionment methods in assessing source contributions to daily PM(2.5) mass–mortality associations. Seven research institutions, using varying methods, participated in the estimation of source apportionments of PM(2.5) mass samples collected in Washington, DC, and Phoenix, Arizona, USA. Apportionments were evaluated for their respective associations with mortality using Poisson regressions, allowing a comparative assessment of the extent to which variations in the apportionments contributed to variability in the source-specific mortality results. The various research groups generally identified the same major source types, each with similar elemental makeups. Intergroup correlation analyses indicated that soil-, sulfate-, residual oil-, and salt-associated mass were most unambiguously identified by various methods, whereas vegetative burning and traffic were less consistent. Aggregate source-specific mortality relative risk (RR) estimate confidence intervals overlapped each other, but the sulfate-related PM(2.5) component was most consistently significant across analyses in these cities. Analyses indicated that source types were a significant predictor of RR, whereas apportionment group differences were not. Variations in the source apportionments added only some 15% to the mortality regression uncertainties. These results provide supportive evidence that existing PM(2.5) source apportionment methods can be used to derive reliable insights into the source components that contribute to PM(2.5) health effects
Atrial fibrillation, anticoagulation management and risk of stroke in the Cardiomyopathy/Myocarditis registry of the EURObservational Research Programme of the European Society of Cardiology
Aims:
Cardiomyopathies are a heterogeneous group of disorders that increase the risk for atrial fibrillation (AF). The aim of the study is to assess the prevalence of AF, anticoagulation management, and risk of stroke/transient ischaemic attack (TIA) in patients with cardiomyopathy.
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Methods and results:
Three thousand two hundred eight consecutive adult patients with cardiomyopathy (34.9% female; median age: 55.0 years) were prospectively enrolled as part of the EURObservational Research Programme Cardiomyopathy/Myocarditis Registry. At baseline, 903 (28.2%) patients had AF (29.4% dilated, 27.5% hypertrophic, 51.5% restrictive, and 14.7% arrhythmogenic right ventricular cardiomyopathy, P < 0.001). AF was associated with more advanced New York Heart Association class (P < 0.001), increased prevalence of cardiovascular risk factors and co‐morbidities, and a history of stroke/TIA (P < 0.001). Oral anticoagulation was administered in 71.7% of patients with AF (vitamin K antagonist: 51.6%; direct oral anticoagulant: 20.1%). At 1 year follow‐up, the incidence of cardiovascular endpoints was as follows: stroke/TIA 1.85% (AF vs. non‐AF: 3.17% vs. 1.19%, P < 0.001), death from any cause 3.43% (AF vs. non‐AF: 5.39% vs. 2.50%, P < 0.001), and death from heart failure 1.67% (AF vs. non‐AF: 2.44% vs. 1.31%, P = 0.033). The independent predictors for stroke/TIA were as follows: AF [odds ratio (OR) 2.812, P = 0.005], history of stroke (OR 7.311, P = 0.010), and anaemia (OR 3.119, P = 0.006).
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Conclusions:
The study reveals a high prevalence and diverse distribution of AF in patients with cardiomyopathies, inadequate anticoagulation regimen, and high risk of stroke/TIA in this population
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Individual common variants exert weak effects on the risk for autism spectrum disorders.
While it is apparent that rare variation can play an important role in the genetic architecture of autism spectrum disorders (ASDs), the contribution of common variation to the risk of developing ASD is less clear. To produce a more comprehensive picture, we report Stage 2 of the Autism Genome Project genome-wide association study, adding 1301 ASD families and bringing the total to 2705 families analysed (Stages 1 and 2). In addition to evaluating the association of individual single nucleotide polymorphisms (SNPs), we also sought evidence that common variants, en masse, might affect the risk. Despite genotyping over a million SNPs covering the genome, no single SNP shows significant association with ASD or selected phenotypes at a genome-wide level. The SNP that achieves the smallest P-value from secondary analyses is rs1718101. It falls in CNTNAP2, a gene previously implicated in susceptibility for ASD. This SNP also shows modest association with age of word/phrase acquisition in ASD subjects, of interest because features of language development are also associated with other variation in CNTNAP2. In contrast, allele scores derived from the transmission of common alleles to Stage 1 cases significantly predict case status in the independent Stage 2 sample. Despite being significant, the variance explained by these allele scores was small (Vm< 1%). Based on results from individual SNPs and their en masse effect on risk, as inferred from the allele score results, it is reasonable to conclude that common variants affect the risk for ASD but their individual effects are modest
Single hadron response measurement and calorimeter jet energy scale uncertainty with the ATLAS detector at the LHC
The uncertainty on the calorimeter energy response to jets of particles is
derived for the ATLAS experiment at the Large Hadron Collider (LHC). First, the
calorimeter response to single isolated charged hadrons is measured and
compared to the Monte Carlo simulation using proton-proton collisions at
centre-of-mass energies of sqrt(s) = 900 GeV and 7 TeV collected during 2009
and 2010. Then, using the decay of K_s and Lambda particles, the calorimeter
response to specific types of particles (positively and negatively charged
pions, protons, and anti-protons) is measured and compared to the Monte Carlo
predictions. Finally, the jet energy scale uncertainty is determined by
propagating the response uncertainty for single charged and neutral particles
to jets. The response uncertainty is 2-5% for central isolated hadrons and 1-3%
for the final calorimeter jet energy scale.Comment: 24 pages plus author list (36 pages total), 23 figures, 1 table,
submitted to European Physical Journal
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