Hepsin activates pro-hepatocyte growth factor and is inhibited by hepatocyte growth factor activator inhibitor-1B (HAI-1B) and HAI-2

Hepsin, a type II transmembrane serine protease, is highly upregulated in prostate cancer and promotes tumor progression and metastasis. We generated a soluble form of hepsin comprising the entire extracellular domain to show that it efficiently converts single-chain hepatocyte growth factor (pro-HGF) into biologically active two-chain HGF. Hepsin activity was potently inhibited by soluble forms of the bi-Kunitz domain inhibitors HAI-1B (IC(50) 21.1+/-2.7 nM) and HAI-2 (IC(50) 1.3+/-0.3 nM). Enzymatic assays with HAI-1B Kunitz domain mutants (R260A and K401A) further demonstrated that inhibition was due to Kunitz domain-1. The results suggest a functional link between hepsin and the HGF/Met pathway, which may contribute to tumor progression.     

Chaotic mixer improves microarray hybridization

Hybridization is an important aspect of microarray experimental design which influences array signal levels and the repeatability of data within an array and across different arrays. Current methods typically require 24h and use target inefficiently. In these studies, we compare hybridization signals obtained in conventional static hybridization, which depends on diffusional target delivery, with signals obtained in a dynamic hybridization chamber, which employs a fluid mixer based on chaotic advection theory to deliver targets across a conventional glass slide array. Microarrays were printed with a pattern of 102 identical probe spots containing a 65-mer oligonucleotide capture probe. Hybridization of a 725-bp fluorescently labeled target was used to measure average target hybridization levels, local signal-to-noise ratios, and array hybridization uniformity. Dynamic hybridization for 1h with 1 or 10ng of target DNA increased hybridization signal intensities approximately threefold over a 24-h static hybridization. Similarly, a 10- or 60-min dynamic hybridization of 10ng of target DNA increased hybridization signal intensities fourfold over a 24h static hybridization. In time course studies, static hybridization reached a maximum within 8 to 12h using either 1 or 10ng of target. In time course studies using the dynamic hybridization chamber, hybridization using 1ng of target increased to a maximum at 4h and that using 10ng of target did not vary over the time points tested. In comparison to static hybridization, dynamic hybridization reduced the signal-to-noise ratios threefold and reduced spot-to-spot variation twofold. Therefore, we conclude that dynamic hybridization based on a chaotic mixer design improves both the speed of hybridization and the maximum level of hybridization while increasing signal-to-noise ratios and reducing spot-to-spot variation.     

The effect of marriage on utilization of colorectal endoscopy exam in the United States

Purpose: This study examines the association between marriage and colorectal endoscopy exam, and whether this association varies by gender and financial benefits of marriage including improved access to health insurance and pooled family income. Methods: Representative survey data of the non-institutionalized United States population were used from the 2000, 2005, and 2008 National Health Interview Survey. Analyses targeted persons 50-85 years of age without a personal history of cancer and with complete information on all study variables (n=21,760). Multivariate logistic regression was used to model marital status differences in the probability of undergoing a colorectal endoscopy exam with interaction effects used to model variation over time by gender, health insurance, and poverty level. Results: Married persons were more likely than unmarried persons to report ever having undergone a colorectal endoscopy exam (odds ratio [OR], 1.21; 95% confidence interval [CI], 1.12-1.29), and the difference between married and unmarried persons in the probability of undergoing a colorectal endoscopy exam remained stable over time. Married persons were more likely than unmarried persons to report having undergone a colorectal endoscopy exam within the past 10 years (OR, 1.49; 95% CI, 1.15-1.95). For each survey year, married men were significantly more likely than women and unmarried men to report having undergone a colorectal endoscopy exam. For example, in 2008, 56% of married men reported having undergone a colorectal endoscopy exam, compared to 49% of unmarried men, 52% of married women, and 50% of unmarried women. Among persons with health insurance, married persons were significantly more likely than unmarried persons to have undergone a colorectal endoscopy exam. Among persons who were poor, there was no difference by marital status in the likelihood of having undergone a colorectal endoscopy exam. However, among persons who were not poor, married persons were more likely than unmarried persons to have undergone a colorectal endoscopy exam. Conclusion: Given that colorectal endoscopy exams are a potentially life-saving procedure, persistently higher uptake of colorectal endoscopy for married persons over time may be an important health promoting benefit of marriage. Therefore, clinicians and policy makers should focus on improving the use of cancer prevention services among unmarried persons.     

Morphological Changes in the Midgut of Aedes aegypti L. (Diptera: Culicidae) Larvae Following Exposure to an Annona coriacea (Magnoliales: Annonaceae) Extract

Bioinsecticides are important in the control of disease vectors, but data regarding their physiological effects on target insects are incomplete. This study describes morphological changes that occur in the midgut of third instar Aedes aegypti L. (Diptera: Culicidae) following treatment with a methanolic extract of Annona coriacea (Magnoliales: Annonaceae). Dissected midguts were subdivided into anterior and posterior regions and analyzed by light and scanning electron microscopy. Insects exposed to the extract displayed intense, destructive cytoplasmic vacuolization in columnar and regenerative midgut cells. The apical surfaces of columnar cells exhibited cytoplasmic protrusions oriented toward the lumen, suggesting that these cells could be involved in apocrine secretory processes and/or apoptosis. We report that A. coriacea extracts induced morphological alterations in the midgut of A. aegypti midgut larvae, supporting the use of plant extracts for control of the dengue vector.     

Étude CESAR : justification de l’assistance respiratoire extra corporelle pour les graves syndromes de détresse respiratoire de l’adulte

BackgroundSevere acute respiratory failure in adults still has a high mortality in adults despite improvements in ventilation techniques and other treatments. The evidence about the effectiveness of extracorporeal membrane oxygenation (ECMO) was equivocal.MethodNational multi-center pragmatic randomized controlled trial. 180 adults (18-65 years) with severe (Murray score > 3.0 or pH < 7.2) but potentially reversible respiratory failure were randomized to receive either continued conventional management (CM) or to be transferred to Glenfield Hospital, Leicester, UK for consideration of ECMO. Patients were excluded if they had been on high pressure (> 30 cm H₂O of peak inspiratory pressure) and/or high FiO₂ (> 0.8) ventilation for > 7 days; had signs of intra-cranial bleeding ; had any other contra-indication to limited heparinisation ; or had any contra-indication to continuation of active treatment. The primary outcome measure was death or severe disability at six months. Analysis was by intention to treat.Results766 patients were screened. 180 were randomised; 90 to the ECMO arm of whom 68 received ECMO. No cm patients received ECMO. Fewer patients in the ECMO arm than the cm arm had died or were severely disabled 6 months after randomisation, (33/90 (36.7%) vs 46/87 (52.9%) ; RR=0.69 (95%CI 0.50 to 0.97) ; p=0.030). Only one patient (in the cm arm) was known to be severely disabled at 6 months.Randomised controlled trial and economic evaluationControlled Trial of Conventional Ventilatory Support vs Extracorporeal Membrane Oxygenation for Severe Adult Respiratory Failure (CESAR) [ISRCTN47279827].     

The ecological importance of unregulated tributaries to macroinvertebrate diversity and community composition in a regulated river

Hydrobiologia - In regulated rivers, dams alter longitudinal gradients in flow regimes, geomorphology, water quality and temperature with associated impacts on aquatic biota. Unregulated...     

CD44 Plays a Functional Role in Helicobacter pylori-induced Epithelial Cell Proliferation

The cytotoxin-associated gene (Cag) pathogenicity island is a strain-specific constituent of Helicobacter pylori (H. pylori) that augments cancer risk. CagA translocates into the cytoplasm where it stimulates cell signaling through the interaction with tyrosine kinase c-Met receptor, leading cellular proliferation. Identified as a potential gastric stem cell marker, cluster-of-differentiation (CD) CD44 also acts as a co-receptor for c-Met, but whether it plays a functional role in H. pylori-induced epithelial proliferation is unknown. We tested the hypothesis that CD44 plays a functional role in H. pylori-induced epithelial cell proliferation. To assay changes in gastric epithelial cell proliferation in relation to the direct interaction with H. pylori, human- and mouse-derived gastric organoids were infected with the G27 H. pylori strain or a mutant G27 strain bearing cagA deletion (∆CagA::cat). Epithelial proliferation was quantified by EdU immunostaining. Phosphorylation of c-Met was analyzed by immunoprecipitation followed by Western blot analysis for expression of CD44 and CagA. H. pylori infection of both mouse- and human-derived gastric organoids induced epithelial proliferation that correlated with c-Met phosphorylation. CagA and CD44 co-immunoprecipitated with phosphorylated c-Met. The formation of this complex did not occur in organoids infected with ∆CagA::cat. Epithelial proliferation in response to H. pylori infection was lost in infected organoids derived from CD44-deficient mouse stomachs. Human-derived fundic gastric organoids exhibited an induction in proliferation when infected with H. pylorithat was not seen in organoids pre-treated with a peptide inhibitor specific to CD44. In the well-established Mongolian gerbil model of gastric cancer, animals treated with CD44 peptide inhibitor Pep1, resulted in the inhibition of H. pylori-induced proliferation and associated atrophic gastritis. The current study reports a unique approach to study H. pylori interaction with the human gastric epithelium. Here, we show that CD44 plays a functional role in H. pylori-induced epithelial cell proliferation.     

Evidence for diet partitioning among three coexisting native freshwater fishes in South Africa's Cape Fold Ecoregion

The partitioning of limited resources commonly explains how different species can coexist within the same ecological community. In this 2010 study, the diets of three coexisting freshwater fishes (Cape galaxias Galaxias zebratus, n = 27; Cape kurper Sandelia capensis, n = 60; Breede River redfin Pseudobarbus burchelli, n = 77) were characterised and compared in three headwater streams in South Africa's Cape Fold Ecoregion using gut contents and stable isotope analyses. These data were analysed to ascertain whether the three species exploit distinct trophic niches. Both approaches provided evidence that these species occupy different trophic niches, though with some overlap. However, dietary differences among sites were not consistent and were probably influenced by site-specific factors like resource availability. Pseudobarbus burchelli had a broader niche breadth at Tierkloof Stream than the other two species, but not at Waaihoek or Tierstel Streams. Our results also suggest that P. burchelli consumed a more omnivorous diet than do the other two species, whereas S. capensis occupied a higher trophic position than the other two species and consumed vertebrates. Our findings suggest that these species occupy non-equivalent feeding niches in Cape Fold Ecoregion headwater streams, and that diet partitioning might facilitate their coexistence in these systems.