Ocean circulation model predicts high genetic structure observed in a long-lived pelagic developer.

Understanding the movement of genes and individuals across marine seascapes is a long-standing challenge in marine ecology and can inform our understanding of local adaptation, the persistence and movement of populations, and the spatial scale of effective management. Patterns of gene flow in the ocean are often inferred based on population genetic analyses coupled with knowledge of species' dispersive life histories. However, genetic structure is the result of time-integrated processes and may not capture present-day connectivity between populations. Here, we use a high-resolution oceanographic circulation model to predict larval dispersal along the complex coastline of western Canada that includes the transition between two well-studied zoogeographic provinces. We simulate dispersal in a benthic sea star with a 6-10 week pelagic larval phase and test predictions of this model against previously observed genetic structure including a strong phylogeographic break within the zoogeographical transition zone. We also test predictions with new genetic sampling in a site within the phylogeographic break. We find that the coupled genetic and circulation model predicts the high degree of genetic structure observed in this species, despite its long pelagic duration. High genetic structure on this complex coastline can thus be explained through ocean circulation patterns, which tend to retain passive larvae within 20-50 km of their parents, suggesting a necessity for close-knit design of Marine Protected Area networks.

Associations of IL6 polymorphisms with lung function decline and COPD.

BACKGROUND: Interleukin-6 (IL6) is a pleiotropic pro-inflammatory and immunomodulatory cytokine which probably plays an important role in the pathogenesis of chronic obstructive pulmonary disease (COPD). There is a functional single nucleotide polymorphism (SNP), -174G/C, in the promoter region of IL6. It was hypothesised that IL6 SNPs influence susceptibility for impaired lung function and COPD in smokers. METHODS: Seven and five SNPs in IL6 were genotyped in two nested case-control samples derived from the Lung Health Study (LHS) based on phenotypes of rate of decline of forced expiratory volume in 1 s (FEV(1)) over 5 years and baseline FEV(1) at the beginning of the LHS. Serum IL6 concentrations were measured for all subjects. A partially overlapping panel of nine IL6 SNPs was genotyped in 389 cases of COPD from the National Emphysema Treatment Trial (NETT) and 420 controls from the Normative Aging Study (NAS). RESULTS: In the LHS, three IL6 SNPs were associated with decline in FEV(1) (0.023< or =p< or =0.041 in additive models). Among them, the IL6_-174C allele was associated with a rapid decline in lung function. The association was more significant in a genotype-based analysis (p = 0.006). In the NETT-NAS study, IL6_-174G/C and four other IL6 SNPs, all of which are in linkage disequilibrium with IL6_-174G/C, were associated with susceptibility to COPD (0.01< or =p< or =0.04 in additive genetic models). CONCLUSION: The results suggest that the IL6_-174G/C SNP is associated with a rapid decline in FEV(1) and susceptibility to COPD in smokers.

Polymorphic variation in surfactant protein B is associated with COPD exacerbations.

Exacerbations of chronic obstructive pulmonary disease (COPD) reduce quality of life and increase mortality. Genetic variation might explain the substantial variability seen in exacerbation frequency among COPD subjects with similar lung function. Polymorphisms in five candidate genes, previously associated with COPD susceptibility, were analysed in order to determine whether they demonstrated association with COPD exacerbations. A total of 88 single nucleotide polymorphisms (SNPs) in the genes microsomal epoxide hydrolase (EPHX1), transforming growth factor, beta-1 (TGFB1), serpin peptidase inhibitor, clade E (nexin, plasminogen activator inhibitor type 1), member 2 (SERPINE2), glutathione S-transferase pi (GSTP1) and surfactant protein B (SFTPB) were genotyped in 389 non-Hispanic white participants in the National Emphysema Treatment Trial. Exacerbations were defined as COPD-related emergency room visits or hospitalisations using the Centers for Medicare and Medicaid Services claims data. One or more exacerbations were experienced by 216 (56%) subjects during the study period. An SFTPB promoter polymorphism, rs3024791, was associated with COPD exacerbations. Logistic regression models, analysing a binary outcome of presence or absence of exacerbations, confirmed the association of rs3024791 with COPD exacerbations. Negative binomial regression models demonstrated association of multiple SFTPB SNPs (rs2118177, rs2304566, rs1130866 and rs3024791) with exacerbation rates. Polymorphisms in EPHX1, GSTP1, TGFB1 and SERPINE2 did not demonstrate association with COPD exacerbations. In conclusion, genetic variation in surfactant protein B is associated with chronic obstructive pulmonary disease susceptibility and exacerbation frequency.

Clinical determinants of exacerbations in severe, early-onset COPD.

Chronic obstructive pulmonary disease (COPD) exacerbations impair health. The present authors analysed participants in the Boston Early-Onset COPD Study for familial aggregation and propensity for COPD exacerbations. In the present study, two exacerbation outcomes, episodes of cough and phlegm, and frequent exacerbations were analysed with multivariable modelling and generalised estimating equations. In early-onset COPD probands, passive tobacco smoke exposure within the home was strongly associated with episodes of cough and phlegm. Chronic phlegm production was associated with both exacerbation phenotypes in probands. In first-degree relatives of early-onset COPD probands, chronic bronchitis, episodic wheezing, pneumonia and active smoking were associated with the episodes of cough and phlegm phenotype. In relatives, identical characteristics plus exertional dyspnoea were associated with frequent exacerbations. Exacerbation risk increased with declining lung function. Familial aggregation for episodes of cough and phlegm was observed in relatives with severe obstruction. In conclusion, passive smoke exposure increases morbidity in severe early-onset chronic obstructive pulmonary disease probands, and chronic obstructive pulmonary disease exacerbations correlate with chronic sputum production in probands and relatives. The familial aggregation of exacerbations suggests a genetic basis for susceptibility to chronic obstructive pulmonary disease exacerbations.

The scimitar syndrome.

The clinical spectrum of the scimitar syndrome ranges from severely ill infants to asymptomatic adults. The true incidence of the disorder is unknown because the syndrome may remain undetected in asymptomatic patients until a chest roentgenogram is obtained. We have presented the contrasting clinical experiences of two adult women, one with few symptoms and a benign course, and the other with exacerbation of her asthma from recurrent upper respiratory tract infections originating in the lower lobe of her right lung. Improvement resulted from surgical resection of this congenitally abnormal, bronchiectatic segment of lung.

Use of intrapleural streptokinase in the treatment of thoracic empyema.

The incidence of pleural effusions in bacterial pneumonia may exceed 40%, a factor that may be related to increased morbidity and mortality. Options in the treatment of complicated pleural effusions or empyema, when unresponsive to closed tube drainage, include repositioning of the indwelling tube thoracostomy or insertion of additional chest tubes, instillation of intrapleural streptokinase, and surgical intervention. The authors describe the course of three patients wherein the use of intrapleural streptokinase was efficacious in effecting prompt drainage of previously inadequately evacuated empyema, thus eliminating the necessity for further invasive intervention.