Kinetics of acute hepatitis B virus infection in humans

Using patient data from a unique single source outbreak of hepatitis B virus (HBV) infection, we have characterized the kinetics of acute HBV infection by monitoring viral turnover in the serum during the late incubation and clinical phases of the disease in humans. HBV replicates rapidly with minimally estimated doubling times ranging between 2.2 and 5.8 d (mean 3.7 ± 1.5 d). After a peak viral load in serum of nearly 1010 HBV DNA copies/ml is attained, clearance of HBV DNA follows a two or three phase decay pattern with an initial rapid decline characterized by mean half-life (t1/2) of 3.7 ± 1.2 d, similar to the t1/2 observed in the noncytolytic clearance of covalently closed circular DNA for other hepadnaviruses. The final phase of virion clearance occurs at a variable rate (t1/2 of 4.8 to 284 d) and may relate to the rate of loss of infected hepatocytes. Free virus has a mean t1/2 of at most 1.2 ± 0.6 d. We estimate a peak HBV production rate of at least 1013 virions/day and a maximum production rate of an infected hepatocyte of 200–1,000 virions/day, on average. At this peak rate of virion production we estimate that every possible single and most double mutations would be created each day

Paraoxonase gene polymorphisms and haplotype analysis in a stroke population

Peer reviewedPublisher PD

A new method for atmospheric detection of the CH3O2 radical

A new method for measurement of the methyl peroxy (CH3O2) radical has been developed using the conversion of CH3O2 into CH3O by excess NO with subsequent detection of CH3O by fluorescence assay by gas expansion (FAGE) with laser excitation at ca. 298 nm. The method can also directly detect CH3O, when no nitric oxide is added. Laboratory calibrations were performed to characterise the FAGE instrument sensitivity using the conventional radical source employed in OH calibration with conversion of a known concentration of OH into CH3O2 via reaction with CH4 in the presence of O2. Detection limits of 3.8 × 108 and 3.0 × 108 molecule cm−3 were determined for CH3O2 and CH3O respectively for a signal-to-noise ratio of 2 and 5 min averaging time. Averaging over 1 h reduces the detection limit for CH3O2 to 1.1 × 108 molecule cm−3, which is comparable to atmospheric concentrations. The kinetics of the second-order decay of CH3O2 via its self-reaction were observed in HIRAC (Highly Instrumented Reactor for Atmospheric Chemistry) at 295 K and 1 bar and used as an alternative method of calibration to obtain a calibration constant with overlapping error limits at the 1σ level with the result of the conventional method of calibration. The overall uncertainties of the two methods of calibrations are similar – 15 % for the kinetic method and 17 % for the conventional method – and are discussed in detail. The capability to quantitatively measure CH3O in chamber experiments is demonstrated via observation in HIRAC of CH3O formed as a product of the CH3O2 self-reaction

Structural brain complexity and cognitive decline in late life : A longitudinal study in the Aberdeen 1936 Birth Cohort

Copyright © 2014 Elsevier Inc. All rights reserved.Peer reviewedPostprin

Development of the PsAQoL: a quality of life instrument specific to psoriatic arthritis

Background: Patient reported outcome measures used in studies of psoriatic arthritis (PsA) have been found to be inadequate for determining the impact of the disease from the patient’s perspective. Objective: To produce the PsAQoL, a PsA-specific quality of life (QoL) instrument, employing the needs based model of QoL that would be relevant and acceptable to respondents, valid, and reliable. Methods: Content was derived from qualitative interviews conducted with patients with PsA. Face and content validity were assessed by field test interviews with a new sample of patients with PsA. A postal survey was conducted to improve the scaling properties of the new measure. Finally, a test-retest postal survey was used to identify the final measure and to test its scaling properties, reliability, internal consistency, and validity. Results: Analysis of the qualitative interview transcripts identified a 51 item questionnaire. Field test interviews confirmed the acceptability and relevance of the measure. Analysis of data from the first postal survey (n = 94) reduced the questionnaire to 35 items. Rasch analysis of data from the test-retest survey (n = 286) identified a 20 item version of the PsAQoL with good item fit. This version had excellent internal consistency (a = 0.91), test-retest reliability (0.89), and validity. Conclusions: The PsAQoL is a valuable tool for assessing the impact of interventions for PsA in clinical studies and trials. It is well accepted by patients, taking about three minutes to complete, is easy to administer, and has excellent scaling and psychometric properties

LHAPDF : PDF Use from the Tevatron to the LHC

Parton Density Functions (PDFs) and their uncertainties are extremely important topics for both the Tevatron and the LHC. Experiments at the Tevatron can enhance this knowledge not only by constraining the PDF fits, but also by developing and refining the available PDF tools through feed-back from the experiments that are currently analyzing the highest energy hadron collider data available. It is important that the community has standardized tools and methods at its disposal. In this note we summarize briefly the most recent developments of the The Les Houches Accord PDF (LHAPDF), which is the modern replacement for PDFLIB. We also outline and compare the methods of quantifying the impact of PDF uncertainties on physical observables. The PDF weighting method for propagating errors from PDFs to event generator observables is outlined in detail, and example code for using this method with PYTHIA is also included

Childhood IQ and marriage by mid-life: the Scottish Mental Survey 1932 and the Midspan Studies

The study examined the influence of IQ at age 11 years on marital status by mid-adulthood. The combined databases of the Scottish Mental Survey 1932 and the Midspan studies provided data from 883 subjects. With regard to IQ at age 11, there was an interaction between sex and marital status by mid-adulthood (p = 0.0001). Women who had ever-married achieved mean lower childhood IQ scores than women who had never-married (p < 0.001). Conversely, there was a trend for men who had ever-married to achieve higher childhood IQ scores than men who had never-married (p = 0.07). In men, the odds ratio of ever marrying was 1.35 (95% CI 0.98–1.86&#59; p = 0.07) for each standard deviation increase in childhood IQ. Among women, the odds ratio of ever marrying by mid-life was 0.42 (95% CI 0.27–0.64; p = 0.0001) for each standard deviation increase in childhood IQ. Mid-life social class had a similar association with marriage, with women in more professional jobs and men in more manual jobs being less likely to have ever-married by mid-life. Adjustment for the effects of mid-life social class and height on the association between childhood IQ and later marriage, and vice versa, attenuated the effects somewhat, but suggested that IQ, height and social class acted partly independently

Childhood IQ and social factors on smoking behaviour, lung function and smoking-related outcomes in adulthood: linking the Scottish Mental Survey 1932 and the Midspan studies

OBJECTIVE: To investigate the associations of childhood IQ and adult social factors, and smoking behaviour, lung function (forced expiratory volume in one second; FEV(1)), and smoking-related outcomes in adulthood. DESIGN: Retrospective cohort study. METHOD: Participants were from the Midspan prospective studies conducted on Scottish adults in the 1970s. The sample consisted of 938 Midspan participants born in 1921 who were successfully matched with their cognitive ability test results on the Scottish Mental Survey 1932. RESULTS: Structural equation modelling showed that age 11 IQ was not directly associated with smoking consumption, but that IQ and adult social class had indirect effects on smoking consumption via deprivation category. The influence of IQ on FEV(1) was partly indirect via social class. Gender influenced smoking consumption and also IQ and social class. There was a 21% higher risk of having a smoking-related hospital admission, cancer, or death during 25 years of follow-up for each standard deviation disadvantage in IQ. Adjustment for adult social class, deprivation category, and smoking reduced the association to 10%. CONCLUSION: Childhood IQ was associated with social factors which influenced lung function in adulthood, but was not associated directly with smoking consumption. In future studies, it is important to consider other pathways which may account for variance in the link between childhood IQ and health in later life