BACKGROUND The global obesity epidemic has paralleled a decrease in semen quality. Yet, the association between obesity and sperm parameters remains controversial. The purpose of this report was to ...update the evidence on the association between BMI and sperm count through a systematic review with meta-analysis. METHODS A systematic review of available literature (with no language restriction) was performed to investigate the impact of BMI on sperm count. Relevant studies published until June 2012 were identified from a Pubmed and EMBASE search. We also included unpublished data (n = 717 men) obtained from the Infertility Center of Bondy, France. Abstracts of relevant articles were examined and studies that could be included in this review were retrieved. Authors of relevant studies for the meta-analysis were contacted by email and asked to provide standardized data. RESULTS A total of 21 studies were included in the meta-analysis, resulting in a sample of 13 077 men from the general population and attending fertility clinics. Data were stratified according to the total sperm count as normozoospermia, oligozoospermia and azoospermia. Standardized weighted mean differences in sperm concentration did not differ significantly across BMI categories. There was a J-shaped relationship between BMI categories and risk of oligozoospermia or azoospermia. Compared with men of normal weight, the odds ratio (95% confidence interval) for oligozoospermia or azoospermia was 1.15 (0.93-1.43) for underweight, 1.11 (1.01-1.21) for overweight, 1.28 (1.06-1.55) for obese and 2.04 (1.59-2.62) for morbidly obese men. CONCLUSIONS Overweight and obesity were associated with an increased prevalence of azoospermia or oligozoospermia. The main limitation of this report is that studied populations varied, with men recruited from both the general population and infertile couples. Whether weight normalization could improve sperm parameters should be evaluated further.
BACKGROUND: Studies have suggested that the quality of human semen has been declining over recent decades, presumably because of lifestyle or environmental factors. METHODS: Polychlorinated biphenyls ...and organochlorine pesticides were analysed in the plasma of 25 men with poor semen quality, 20 men with normal semen quality and idiopathic subfertility and 27 men with normal semen quality and female factor subfertility. Samples of seminal fluid were also analysed to assess the relationship between the levels in blood and semen. RESULTS: The results indicate no difference in the levels of organochlorines between the groups. The levels of organochlorines in seminal fluid were proportional to the levels in plasma, but ∼40 times lower. Men with poor semen quality were three times more likely to be obese than men with normal semen quality. There was also a significant negative correlation between semen quality parameters and body mass index among men with normal semen quality. The prevalence of sedentary work was lowest among men with the best semen quality. CONCLUSIONS: Poor semen quality was found to be associated with sedentary work and obesity but not with plasma levels of persistent organochlorines. More research is needed to assess whether sedentary lifestyle and obesity are causal factors in the decline of semen quality.
The Atmospheric River Tracking Method Intercomparison Project
(ARTMIP) is an international collaborative effort to understand and quantify
the uncertainties in atmospheric river (AR) science based on ...detection
algorithm alone. Currently, there are many AR identification and tracking
algorithms in the literature with a wide range of techniques and conclusions.
ARTMIP strives to provide the community with information on different
methodologies and provide guidance on the most appropriate algorithm for a
given science question or region of interest. All ARTMIP participants will
implement their detection algorithms on a specified common dataset for a
defined period of time. The project is divided into two phases: Tier 1 will
utilize the Modern-Era Retrospective analysis for Research and Applications,
version 2 (MERRA-2) reanalysis from January 1980 to June 2017 and will be
used as a baseline for all subsequent comparisons. Participation in Tier 1 is
required. Tier 2 will be optional and include sensitivity studies designed
around specific science questions, such as reanalysis uncertainty and climate
change. High-resolution reanalysis and/or model output will be used wherever
possible. Proposed metrics include AR frequency, duration, intensity, and
precipitation attributable to ARs. Here, we present the ARTMIP experimental
design, timeline, project requirements, and a brief description of the
variety of methodologies in the current literature. We also present results
from our 1-month “proof-of-concept” trial run designed to illustrate the
utility and feasibility of the ARTMIP project.
With the increasing incidence of prostate cancer, identifying common genetic variants that confer risk of the disease is important. Here we report such a variant on chromosome 8q24, a region ...initially identified through a study of Icelandic families. Allele −8 of the microsatellite DG8S737 was associated with prostate cancer in three case-control series of European ancestry from Iceland, Sweden and the US. The estimated odds ratio (OR) of the allele is 1.62 (P = 2.7 × 10−11). About 19% of affected men and 13% of the general population carry at least one copy, yielding a population attributable risk (PAR) of ∼8%. The association was also replicated in an African American case-control group with a similar OR, in which 41% of affected individuals and 30% of the population are carriers. This leads to a greater estimated PAR (16%) that may contribute to higher incidence of prostate cancer in African American men than in men of European ancestry.
Prey species of the gyrfalcon varied in organochlorine levels, with the principal species, the ptarmigan, having the lowest levels.
Our previous investigations have revealed very high levels of ...organochlorines (OCs) in the Icelandic gyrfalcon
Falco rusticolus, a resident top predator. We now examine six potential prey species of birds, both resident and migratory, in order to elucidate the most likely route of the OCs to the gyrfalcon. The ptarmigan
Lagopus mutus, the most important prey of the gyrfalcon, contained very low levels of OCs. Bioaccumulation of polychlorinated biphenyls (PCBs) and DDTs in mallards
Anas platyrhynchos, tufted ducks
Aythya fuligula, golden plovers
Pluvialis apricaria, purple sandpipers
Calidris maritima, and black guillemots
Cepphus grylle reflected their position in the foodchain. The differences in OC-levels seem nevertheless too high just to reflect the different foodchain levels of these species in Iceland. The winter grounds of the migratory golden plovers and tufted ducks appear to be more contaminated than the Icelandic terrestrial habitat of ptarmigans or the freshwater habitat as reflected in mallards, both resident species. However, spending the winter on the coast in Iceland, results in high levels of contaminants in purple sandpipers and black guillemots. Our results indicate OC contamination of the marine ecosystem in Iceland while the terrestrial and freshwater ecosystems are little affected. It is postulated that gyrfalcons receive the major part of the observed contamination from prey other than ptarmigan, especially birds associated with the marine ecosystem and also from migratory birds.
The levels of several different persistent organochlorines (OCs) in Black Guillemots
Cepphus grylle, collected during the summers of 1976–1996 at Breiðafjörður in W-Iceland, were investigated. The ...levels of about 40 different organochlorines (PCBs, DDTs, chlordanes, toxaphenes, HCH, HCB) were compared with respect to age, sex, fat content, and year of collection. The levels of PCBs correlated very closely with those of DDE, indicating long-range transport as the major source of these contaminants in Iceland, with the ratio PCBs/DDE mostly in the range of 2–5. Unlike the Gyrfalcon
Falco rusticolus, the organochlorine levels did not seem to accumulate substantially with age, neither in males nor females. The variation in the levels of OCs at the age of 2 years was even greater than the variation in OC levels over an age range of 12 years. In immature birds the levels of PCBs, DDE, HCB and β-HCH declined very slowly (
T
1/2 from 12 to 20 years) over the years 1976–1996, whereas the levels of α-HCH and
p,
p′-DDT declined much faster. The levels of
trans-nonachlor, α-chlordane, γ-chlordane, oxychlordane, and toxaphene did not correlate with the year of collection. As the Black Guillemot is mostly a resident seabird, feeding mainly on small fish and invertebrates, this investigation should give a good indication of the temporal trends of organochlorine pollution at Breiðafjörður, Iceland, during this 20 year period and is likely to reflect baseline trends in the marine environment of the North-Atlantic Ocean.
Baseline trends for a range of organochlorine pesticides in the marine environment of the North Atlantic can be inferred.
Constraint-based reconstruction and analysis (COBRA) provides a molecular mechanistic framework for integrative analysis of experimental molecular systems biology data and quantitative prediction of ...physicochemically and biochemically feasible phenotypic states. The COBRA Toolbox is a comprehensive desktop software suite of interoperable COBRA methods. It has found widespread application in biology, biomedicine, and biotechnology because its functions can be flexibly combined to implement tailored COBRA protocols for any biochemical network. This protocol is an update to the COBRA Toolbox v.1.0 and v.2.0. Version 3.0 includes new methods for quality-controlled reconstruction, modeling, topological analysis, strain and experimental design, and network visualization, as well as network integration of chemoinformatic, metabolomic, transcriptomic, proteomic, and thermochemical data. New multi-lingual code integration also enables an expansion in COBRA application scope via high-precision, high-performance, and nonlinear numerical optimization solvers for multi-scale, multi-cellular, and reaction kinetic modeling, respectively. This protocol provides an overview of all these new features and can be adapted to generate and analyze constraint-based models in a wide variety of scenarios. The COBRA Toolbox v.3.0 provides an unparalleled depth of COBRA methods.
We conducted a genome-wide SNP association study on prostate cancer on over 23,000 Icelanders, followed by a replication study including over 15,500 individuals from Europe and the United States. Two ...newly identified variants were shown to be associated with prostate cancer: rs5945572 on Xp11.22 and rs721048 on 2p15 (odds ratios (OR) = 1.23 and 1.15; P = 3.9 × 10−13 and 7.7 × 10−9, respectively). The 2p15 variant shows a significantly stronger association with more aggressive, rather than less aggressive, forms of the disease.
Several copy number variants have been associated with neuropsychiatric disorders and these variants have been shown to also influence cognitive abilities in carriers unaffected by psychiatric ...disorders. Previously, we associated the 15q11.2(BP1-BP2) deletion with specific learning disabilities and a larger corpus callosum. Here we investigate, in a much larger sample, the effect of the 15q11.2(BP1-BP2) deletion on cognitive, structural and functional correlates of dyslexia and dyscalculia. We report that the deletion confers greatest risk of the combined phenotype of dyslexia and dyscalculia. We also show that the deletion associates with a smaller left fusiform gyrus. Moreover, tailored functional magnetic resonance imaging experiments using phonological lexical decision and multiplication verification tasks demonstrate altered activation in the left fusiform and the left angular gyri in carriers. Thus, by using convergent evidence from neuropsychological testing, and structural and functional neuroimaging, we show that the 15q11.2(BP1-BP2) deletion affects cognitive, structural and functional correlates of both dyslexia and dyscalculia.
In Western countries, prostate cancer is the most prevalent cancer of men and one of the leading causes of cancer-related death in men. Several genome-wide association studies have yielded numerous ...common variants conferring risk of prostate cancer. Here, we analyzed 32.5 million variants discovered by whole-genome sequencing 1,795 Icelanders. We identified a new low-frequency variant at 8q24 associated with prostate cancer in European populations, rs188140481A (odds ratio (OR) = 2.90; P(combined) = 6.2 × 10(-34)), with an average risk allele frequency in controls of 0.54%. This variant is only very weakly correlated (r(2) ≤ 0.06) with previously reported risk variants at 8q24, and its association remains significant after adjustment for all known risk-associated variants. Carriers of rs188140481A were diagnosed with prostate cancer 1.26 years younger than non-carriers (P = 0.0059). We also report results for a previously described HOXB13 variant (rs138213197T), confirming it as a prostate cancer risk variant in populations from across Europe.
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