Reweighting UK Biobank corrects for pervasive selection bias due to volunteering.

Background: Biobanks typically rely on volunteer-based sampling. This results in large samples (power) at the cost of representativeness (bias). The problem of volunteer bias is debated.

Risk and Protective Factors of Lifetime Cocaine-Associated Chest Pain.

Cocaine users often present with repetitive events of cocaine-associated chest pain (CACP), clinically resembling acute coronary syndromes. The aim of the study is to describe the specific risk factors for CACP. Cocaine users ( = 316) were recruited for a multicenter cross-sectional study.

Genetic correlates of socio-economic status influence the pattern of shared heritability across mental health traits.

Epidemiological studies show high comorbidity between different mental health problems, indicating that individuals with a diagnosis of one disorder are more likely to develop other mental health problems. Genetic studies reveal substantial sharing of genetic factors across mental health traits. However, mental health is also genetically correlated with socio-economic status (SES), and it is therefore important to investigate and disentangle the genetic relationship between mental health and SES.

Post-GWAS analysis of six substance use traits improves the identification and functional interpretation of genetic risk loci.

Background: Little is known about the functional mechanisms through which genetic loci associated with substance use traits ascertain their effect. This study aims to identify and functionally annotate loci associated with substance use traits based on their role in genetic regulation of gene expression.

Methods: We evaluated expression Quantitative Trait Loci (eQTLs) from 13 brain regions and whole blood of the Genotype-Tissue Expression (GTEx) database, and from whole blood of the Depression Genes and Networks (DGN) database.

Genetic heterogeneity in self-reported depressive symptoms identified through genetic analyses of the PHQ-9.

Background: Depression is a clinically heterogeneous disorder. Previous large-scale genetic studies of depression have explored genetic risk factors of depression case-control status or aggregated sums of depressive symptoms, ignoring possible clinical or genetic heterogeneity.

Methods: We analyse data from 148 752 subjects of white British ancestry in the UK Biobank who completed nine items of a self-rated measure of current depressive symptoms: the Patient Health Questionnaire (PHQ-9).

Potential influence of socioeconomic status on genetic correlations between alcohol consumption measures and mental health.

Background: Frequency and quantity of alcohol consumption are metrics commonly used to measure alcohol consumption behaviors. Epidemiological studies indicate that these alcohol consumption measures are differentially associated with (mental) health outcomes and socioeconomic status (SES). The current study aims to elucidate to what extent genetic risk factors are shared between frequency and quantity of alcohol consumption, and how these alcohol consumption measures are genetically associated with four broad phenotypic categories: (i) SES; (ii) substance use disorders; (iii) other psychiatric disorders; and (iv) psychological/personality traits.

QT length during methadone maintenance treatment: gene × dose interaction.

Methadone is known to be a risk factor for sudden death by enlarging ECG QT corrected (QTc) interval. For other medical conditions, QTc lengthening has been described as the result of interactions between pharmacological treatments and genetic factors. Former heroin-dependent subjects under methadone maintenance treatment in remission for at last 3 months were recruited.

Exploring the role of low-frequency and rare exonic variants in alcohol and tobacco use.

Background: Alcohol and tobacco use are heritable phenotypes. However, only a small number of common genetic variants have been identified, and common variants account for a modest proportion of the heritability. Therefore, this study aims to investigate the role of low-frequency and rare variants in alcohol and tobacco use.

A tutorial on conducting genome-wide association studies: Quality control and statistical analysis.

Objectives: Genome-wide association studies (GWAS) have become increasingly popular to identify associations between single nucleotide polymorphisms (SNPs) and phenotypic traits. The GWAS method is commonly applied within the social sciences. However, statistical analyses will need to be carefully conducted and the use of dedicated genetics software will be required.

Sensitive life detection strategies for low-biomass environments: optimizing extraction of nucleic acids adsorbing to terrestrial and Mars analogue minerals.

The adsorption of nucleic acids to mineral matrixes can result in low extraction yields and negatively influences molecular microbial ecology studies, in particular for low-biomass environments on Earth and Mars. We determined the recovery of nucleic acids from a range of minerals relevant to Earth and Mars. Clay minerals, but also other silicates and nonsilicates, showed very low recovery (< 1%).

Relationship between the venoconstrictor activity of dihydroergotamine and its pharmacokinetics during acute and chronic oral dosing.

In a double-blind, interindividual comparative study 30 healthy volunteers were randomly allocated to oral treatment with 5 or 10 mg of dihydroergotamine (DHE) or placebo once daily for 16 days. Regional basic venous blood volume (BBV), pressure dependent venous capacitance (CV) of the calf, resting heart rate and blood pressure were determined on Days 1 and 15 of treatment. Plasma concentrations of DHE were monitored on Days 2 and 16.

[Evaluation of air segment plethysmography using computer tomography].

The measurement of tissue volume in the calf area carried out by computer-tomography and planimetry showed a nearly elliptic form, an average bony part of 9.9 ml (9.3%), and an average tissue volume of 97.

[Error magnitude of measurement sensors in air segment plethysmography].

Besides examining the properties of the material involved, this investigation assesses the so-called static and dynamic measurement errors of sensors used for air segment plethysmography. The static error which has been found with the new BN sensors amounts to 8% (old models: 31%-44%). The folding of the interior membrane of the sensor resting upon the skin, which increases proportionately to the stiffness of the material, is discussed as a source of error.