Platelet-Associated CD40/CD154 Mediates Remote Tissue Damage after Mesenteric Ischemia/Reperfusion Injury

Several innate and adaptive immune cell types participate in ischemia/reperfusion induced tissue injury. Amongst them, platelets have received little attention as contributors in the process of tissue damage after ischemia reperfusion (I/R) injury. It is currently unknown whether platelets participate through the immunologically important molecules including, CD40 and when activated, CD154 (CD40L), in the pathogenesis of I/R injury. We hypothesized that constitutive expression of CD40 and activation-induced expression of CD154 on platelets mediate local mesenteric and remote lung tissue damage after I/R injury. Wild type (WT; C57BL/6J), CD40 and CD154 deficient mice underwent mesenteric ischemia for 30 minutes followed by reperfusion for 3 hours. WT mice subjected to mesenteric I/R injury displayed both local intestinal and remote lung damage. In contrast, there was significantly less intestinal damage and no remote lung injury in CD40 and CD154 deficient mice when compared to WT mice. Platelet-depleted WT mice transfused with platelets from CD40 or CD154 deficient mice failed to reconstitute remote lung damage. In contrast, when CD40 or CD154 deficient mice were transfused with WT platelets lung tissue damage was re-established. Together, these findings suggest that multiple mechanisms are involved in local and remote tissue injury and also identify platelet-expressed CD40 and/or CD154 as mediators of remote tissue damage

Changes in the abundance and structure of bacterial communities under long-term fertilization treatments in a peanut monocropping system

Peanut yield and quality are seriously compromised by continuous monoculturing in the red soil region of southern China. Monoculturing can cause soil degradation and an increase in soil-borne diseases. This research aimed to investigate the influence of long-term peanut monocropping and different fertilization treatments on peanut growth, soil physical and chemical properties and soil microbial community. A long-term fertilization experiment established in 1996 was utilized to examine the effect of various fertilization treatments including chemical and organic fertilizers treatments. Deep 16S rRNA gene pyrosequencing highlighted changes in the abundance and structure of bacterial communities, especially of the pathogenic and beneficial bacterial communities in long term chemical fertilizer treatment in comparison to the organic manure treatment. Chemical fertilizer treatment causes a shift in bacterial community structure and decrease in diversity under the long-term monocropping in comparison to organic fertilizer. The abundance of the bacterial pathogen Ralstonia solanacearum, a causative agent of peanut wilt, was found to be associated with a loss of community diversity and loss of the peanut yield. The organic fertilizers more effectively increase microbial diversity in the soil and changed the community structure. Long-term use of the chemical fertilizer leads to a decrease in microbial diversity of the soil and an increase in R. solanacearum with associated increase of peanut wilt. The potential decrease in diversity and competition between the bacterial community and the pathogen may be a contributing factor to increased disease during long-term chemical fertilizer use

US pediatric population-level associations of DXA-measured percentage of body fat with four BMI metrics with cutoffs

Four body mass index (BMI) metrics--BMI, BMI z-score, BMI percentile and BMI%--are commonly used as proxy measures for children's adiposity. We sought to determine a BMI metric that is most strongly associated with measured percentage of body fat (%BF) in the US pediatric population stratified by sex, age and race/ethnicity, and to determine cutoffs that maximize the association for each BMI metric. SUBJECTS, DESIGN AND METHODS: %BF was measured by dual-energy X-ray absorptiometry among N=6120 US boys and girls aged 8.0-17.9 years old from the National Health and Nutrition Examination Survey 1999-2004. We fit piecewise linear regression models with cutoffs to %BF data using each BMI metric as the predictor stratified by sex, race/ethnicity and age. The slopes were modeled differently before and after the cutoffs which were determined on the basis of grid searches