Dietary n-3 fatty acids have suppressive effects on mucin upregulation in mice infected with Pseudomonas aeruginosa

International audienceMucin hypersecretion and mucus plugging in the airways are characteristic features of chronic respiratory diseases like cystic fibrosis (CF) and contribute to morbidity and mortality. In CF, Pseudomonas aeruginosa superinfections in the lung exacerbate inflammation and alter mucus properties. There is increasing evidence that n-3 polyunsaturated fatty acids (PUFAs) exhibit anti-inflammatory properties in many inflammatory diseases while n-6 PUFA arachidonic acid (AA) favors inflammatory mediators such as eicosanoids prostaglandin E2 (PGE2) and leukotriene B4 (LTB4) that may enhance inflammatory reactions. This suggests that n-3 PUFAs may have a protective effect against mucus over-production in airway diseases. Therefore, we hypothesized that n-3 PUFAs may downregulate mucins expression. We designed an absolute real-time PCR assay to assess the effect of a 5-week diet enriched either with n-3 or n-6 PUFAs on the expression of large mucins in the lungs of mice infected by P. aeruginosa. Dietary fatty acids did not influence mucin gene expression in healthy mice. Lung infection induced an increase of the secreted gel-forming mucin Muc5b and a decrease of the membrane bound mucin Muc4. These deregulations are modulated by dietary fatty acids with a suppressive effect of n-3 PUFAs on mucin (increase of Muc5b from 19-fold up to 3.6 x 10(5)-fold for the n-3 PUFAs treated group and the control groups, respectively, 4 days post-infection and decrease of Muc4 from 15-fold up to 3.2 x 10(4)-fold for the control and the n-3 PUFAs treated groups, respectively, 4 days post-infection). Our data suggest that n-3 PUFAs enriched diet represents an inexpensive strategy to prevent or treat mucin overproduction in pulmonary bacterial colonization

An Update on the Use of Modern Financial Instruments in the Insurance Sector

The world's financial markets have exploded with new products and new techniques such as derivatives and securitizations, giving rise to huge new markets. The author reviews recent developments in insurance-linked securities (ILS), financial products that link insurance and reinsurance with these new markets. Pricing and availability problems after Hurricane Katrina have led to newer types of products making their way into these markets. While catastrophe bonds still make up a significant portion of ILS, the risk of not recovering reinsurance receivables, for instance, can now be transferred to the financial markets via credit derivatives. Catastrophe risk can also be packaged as a credit derivative. New participants, like hedge funds and specialized mutual funds, have also caused a revival of exchange-traded ILS. Trading in catastrophe futures and weather derivatives is thriving. Sidecars were revived. Contingent capital is readily available. New perils, combined with others, are being covered. Insurance and reinsurance companies can no longer treat these instruments as a matter of relative pricing between traditional products and ILS. After Katrina, access to multiple sources of capital has become an essential strategic objective. The Geneva Papers (2007) 32, 319–331. doi:10.1057/palgrave.gpp.2510134

Lipid biomarkers, carbon isotopes, and phylogenetic characterization of bacteria in California and Nevada hot springs

Microbial mats were collected from hot springs in California (Eagleville) and Nevada (Paradise Valley and Crescent Valley) to determine bacterial community structure and pathways of carbon cycling in different geothermal environments of the western United States. Phospholipid fatty acids (PLFA) at Eagleville contained even-numbered fatty acids, with 16:0 being the most abundant (48.8%), followed by 18:1ω9c (17.2%), 16:1ω7c/t (6.3%), and 18:0 (6.2%), which are consistent with lipid profiles of cyanobacteria or other phototrophic bacteria. The PLFA profiles at Paradise Valley and Crescent Valley were dominated by similar even-numbered fatty acids; however, branched fatty acids such as iso- and anteiso- 15:0 and 17:0 were also abundant (up to 7.1% compared to 2.0% at Eagleville), suggesting greater relative abundance of heterotrophic bacteria in these springs. Analysis of neutral lipids was only performed on Eagleville and Paradise Valley springs, which revealed abundant bacterial hopanoids including the 2-methylbacteriohopane-32,33,34,35-tetrol (2-methylBHT) that is specific to cyanobacteria; however, the diversity of hopanoid compounds was significantly lower at Eagleville than at Paradise Valley. The carbon-isotope composition of individual PLFA averaged -30.7 ± 1.3%(n = 7) at Eagleville, -28.0 ± 1.8%(n = 3) at Crescent Valley, and -29.7 ± 3.1%(n = 12) at Paradise Valley. Carbon isotope fractionation between PLFA and CO2 was only available for Eagleville (-11.7%) and Paradise Valley (-21.7%), which indicated the predominance of the Calvin cycle for CO2 fixation in these hot springs. Bacterial 16S rRNA genes were extracted from environmental samples at Eagleville and Paradise Valley but not Crescent Valley. Clone libraries indicated the predominance of cyanobacteria (50-75%) at these locations, which is consistent with the lipid profiles. Phylogenetic tree of the 16S rRNA genes indicated that most of the cyanobacterial sequences are unknown and may be specific to the Nevada and California hot springs. Phototrophic green non-sulfur bacteria were also present at Eagleville (13%) and Paradise Valley (7%). The remaining sequences were related to α-, β -, and γ-Proteobacteria, Acidobacteria, Deinococcus/Thermus, Bacteroidetes, and Spirochaetes. However, not all of these sequences were present at each of the springs. Results of this study demonstrate the consistency among lipid profiles (phenotypes), carbon isotopes (biogeochemistry), and 16S rRNA genes (genotypes) of the bacterial community in these hot springs, which cumulatively suggest the importance of cyanobacteria in primary production of biomass under the environmental conditions examined.link_to_subscribed_fulltex

Finite Reinsurance: How does it Concern Supervisors? Some Efficiency Considerations in the Light of Prevailing Regulatory Aims*

Finite reinsurance transactions attracted the attention of insurance supervisors and beyond recently. This paper considers the resulting and ongoing discussion concerning the regulatory environment for finite reinsurance transactions. Consumer protection and financial stability are reflected in the light of cost–benefit considerations as criteria for the further design of finite reinsurance-related regulation and supervision. At the same time, some of the forces that influence the shaping of regulation and supervision are described. This article concludes that few, concise and, in an ideal case, worldwide applicable rules and principles are best suited to guide the development within the field of finite reinsurance. Such rules and principles would most probably have a positive impact on consumer protection and financial stability. This article therefore supports the IAIS intention to consider the topic of finite reinsurance further. The Geneva Papers (2007) 32, 283–300. doi:10.1057/palgrave.gpp.2510137