Grafting on nude mice of living skinquivalents produced using human collagens

Autologous epidermal transplantation for human burn management is an example of a significant breakthrough in tissue engineering. However, the main drawback with this treatment remains the fragility of these grafts during and after surgery. A new human bilayered skin equivalent (hSE) was produced in our laboratory to overcome this problem. The aim of the present work was to study skin regeneration after hSE grafting onto nude mice. A comparative study was carried out over a period of 90 days, between anchored bovine skin equivalent, hSE and hSE+, the latter containing additional matrix components included at concentrations similar to those in human skin in vivo. The addition of a dermal layer to the epidermal sheet led to successful graft take, enhanced healing, and provided mechanical resistance to the grafts after transplantation. In situ analysis of the grafts showed good ultrastructural organization, including the deposition of a continuous basement membrane 1 week after surgery

Qualite des eaux souterraines et risque de pollution en milieu semi-aride. Cas de la cuvette de Cheria (NE Algerien)

Water shortage has become a key problem for all countries and particularly for those in development. In fact, the increase of the populations and the development of urbanism, industries and cultivated land lead to a degradation of the quality of the groundwater and a very significant reduction of the reserves that constitute at times the only source of water for human consumption. After the analisis of the situation of the land, the present work comes in an important moment to establish the characteristics of the complex aquifer of the plateau of Chéria in Algeria and the risks of contamination of the groundwater. This study, which relies in the recent causes of contamination takes into account several factors. We can mention the contamination by blackwaters (waste), the impact of livestock and the climatic conditions. The exploitation of the groundwater from carbonated aquifers, is today the only source that responds to the needs of water for the industrial, human, and agricultural comsumption in the region. In recent years there has been an increase in agricultural and agricultural-related activity. The first results show the existence of a lowering of the piezometric level, as well as important concentrations in nitrates due to anthropic activity which are leading to a deterioration of the quality of drinking water in Chéria.La escasez de agua se ha convertido en un problema crucial para toda la Sociedad y en particular para los paises en vias de desarrollo. En efecto, el crecimiento de la población y el urbanístico, de la industria y de los cultivos pueden conducir a una degradación de la calidad de las aguas subterráneas y una significativa reducción de las reservas que, a menudo, constituyen la única fuente de agua de consumo humano. En este trabajo se evalúan las características del complejo acuífero de la cuenca de Chéria (Argelia) basado en un inventario de las fuentes de contaminación teniendo en cuenta diversos factores, como son la contaminación por aguas residuales, el impacto debido al ganado y las condiciones climáticas. Esto es necesario ya que la explotación de las aguas subterráneas a partir de acuíferos carbonatados es actualmente la única fuente de agua de consumo humano, industrial y agrícola de la región, donde se ha producido un fuerte incremento de consumo en los últimos años. Los resultados de este estudio demuestran la existencia de un descenso del nivel piezométrico y de concentraciones elevadas de nitratos debido a la actividad antrópica, con valores de 80 a 120 mg/l

The cientificWorldJOURNAL Research Article Removal of Triphenylmethane Dyes by Bacterial Consortium

A new consortium of four bacterial isolates (Agrobacterium radiobacter; Bacillus spp.; Sphingomonas paucimobilis, and Aeromonas hydrophila)-(CM-4) was used to degrade and to decolorize triphenylmethane dyes. All bacteria were isolated from activated sludge extracted from a wastewater treatment station of a dyeing industry plant. Individual bacterial isolates exhibited a remarkable colorremoval capability against crystal violet (50 mg/L) and malachite green (50 mg/L) dyes within 24 h. Interestingly, the microbial consortium CM-4 shows a high decolorizing percentage for crystal violet and malachite green, respectively, 91% and 99% within 2 h. The rate of chemical oxygen demand (COD) removal increases after 24 h, reaching 61.5% and 84.2% for crystal violet and malachite green, respectively. UV-Visible absorption spectra, FTIR analysis and the inspection of bacterial cells growth indicated that color removal by the CM-4 was due to biodegradation. Evaluation of mutagenicity by using Salmonella typhimurium test strains, TA98 and TA100 studies revealed that the degradation of crystal violet and malachite green by CM-4 did not lead to mutagenic products. Altogether, these results demonstrated the usefulness of the bacterial consortium in the treatment of the textile dyes

Progression of aortic stenosis after an acute myocardial infarction

Background Myocardial infarction (MI) has been shown to induce fibrotic remodelling of the mitral and tricuspid valves. It is unknown whether MI also induces pathological remodelling of the aortic valve and alters aortic stenosis (AS) progression. We thus compared AS progression after an acute MI and in patients with/without history of MI, and assessed post-MI pathobiological changes within the aortic valve leaflets in a sheep model. Methods Serial echocardiograms in human patients with AS were retrospectively analysed and compared between 3 groups: (1) acute MI at baseline (n=68), (2) prior history of MI (n=45) and (3) controls without MI (n=101). Annualised progression rates of AS severity were compared between these 3 groups. In addition, aortic valves were harvested from 15 sheep: (1) induced inferior MI (n=10) and (2) controls without MI (n=5), for biological and histological analyses. Results In humans, the acute MI, previous MI and control groups had comparable baseline AS severity. Indexed aortic valve area (AVAi) declined faster in the acute MI group compared with controls (−0.07±0.06 vs −0.04±0.04 cm²/m²/year; p=0.004). After adjustment, acute MI status was significantly associated with faster AVAi progression (mean difference: −0.013 (95% CI −0.023 to −0.003) cm²/m²/year, p=0.008). In the post-MI experimental animal model, aortic valve thickness and qualitative/quantitative expression of collagen were significantly increased compared with controls. Conclusions The results of this study suggest that AS progression is accelerated following acute MI, which could be caused by increased collagen production and thickening of the aortic valve after the ischaemic event

Does Hepatitis C Virus Infection Increase Risk for Stroke? A Population-Based Cohort Study

BACKGROUND: The relationship between hepatitis C virus infection and risk of stroke remains inconsistent. This study evaluates the risk of stroke in association with chronic hepatitis C infection in a longitudinal population-based cohort. METHODS: We identified 4,094 adults newly diagnosed with hepatitis C infection in 2002-2004 from the Taiwan National Health Insurance Research Database. Comparison group consisted of 16,376 adults without hepatitis C infection randomly selected from the same dataset, frequency matched by age and sex. Events of stroke from 2002-2008 were ascertained from medical claims (International Classification of Diseases, Ninth Revision, Clinical Modification, ICD-9-CM, codes 430-438). Multivariate adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated for potential associated factors including HCV infection, age, sex, low-income status, urbanization, cessation of cigarette smoking, alcohol-related illness, obesity, history of chronic diseases and medication use. FINDINGS: During 96,752 person-years of follow-up, there were 1981 newly diagnosed stroke cases. The HRs of stroke associated with medical conditions such as hypertension, diabetes and heart disease were 1.48 (95% CI 1.33 to 1.65), 1.23 (95% CI 1.11 to 1.36) and 1.17 (95% CI 1.06 to 1.30), respectively, after adjustment for covariates. The cumulative risk of stroke for people with hepatitis C and without hepatitis C infections was 2.5% and 1.9%, respectively (p<0.0001). Compared with people without hepatitis C infection, the adjusted HR of stroke was 1.27 (95% CI 1.14 to 1.41) for people with hepatitis C infection. CONCLUSION: Chronic hepatitis C infection increases stroke risk and should be considered an important and independent risk factor

Identification of O-mannosylated Virulence Factors in Ustilago maydis

The O-mannosyltransferase Pmt4 has emerged as crucial for fungal virulence in the animal pathogens Candida albicans or Cryptococcus neoformans as well as in the phytopathogenic fungus Ustilago maydis. Pmt4 O-mannosylates specific target proteins at the Endoplasmic Reticulum. Therefore a deficient O-mannosylation of these target proteins must be responsible for the loss of pathogenicity in pmt4 mutants. Taking advantage of the characteristics described for Pmt4 substrates in Saccharomyces cerevisiae, we performed a proteome-wide bioinformatic approach to identify putative Pmt4 targets in the corn smut fungus U. maydis and validated Pmt4-mediated glycosylation of candidate proteins by electrophoretic mobility shift assays. We found that the signalling mucin Msb2, which regulates appressorium differentiation upstream of the pathogenicity-related MAP kinase cascade, is O-mannosylated by Pmt4. The epistatic relationship of pmt4 and msb2 showed that both are likely to act in the same pathway. Furthermore, constitutive activation of the MAP kinase cascade restored appressorium development in pmt4 mutants, suggesting that during the initial phase of infection the failure to O-mannosylate Msb2 is responsible for the virulence defect of pmt4 mutants. On the other hand we demonstrate that during later stages of pathogenic development Pmt4 affects virulence independently of Msb2, probably by modifying secreted effector proteins. Pit1, a protein required for fungal spreading inside the infected leaf, was also identified as a Pmt4 target. Thus, O-mannosylation of different target proteins affects various stages of pathogenic development in U. maydis

Glycosylation status of the C. albicans cell wall affects the efficiency of neutrophil phagocytosis and killing but not cytokine signaling

The cell wall of the opportunistic human fungal pathogen, Candida albicans is a complex, layered network of rigid structural polysaccharides composed of β-glucans and chitin that is covered with a fibrillar matrix of highly glycosylated mannoproteins. Poly-morphonuclear cells (PMNs, neutrophils) are the most prevalent circulating phagocytic leukocyte in peripheral blood and they are pivotal in the clearance of invading fungal cells from tissues. The importance of cell-wall mannans for the recognition and uptake of C. albicans by human PMNs was therefore investigated. N- and O-glycosylation-deficient mutants were attenuated in binding and phagocytosis by PMNs and this was associated with reduced killing of C. albicans yeast cells. No differences were found in the production of the respiratory burst enzyme myeloperoxidase (MPO) and the neutrophil chemokine IL-8 in PMNs exposed to control and glycosylation-deficient C. albicans strains. Thus, the significant decrease in killing of glycan-deficient C. albicans strains by PMNs is a consequence of a marked reduction in phagocytosis rather than changes in the release of inflammatory mediators by PMNs

Prediction of Phenotype-Associated Genes via a Cellular Network Approach: A Candida albicans Infection Case Study

Candida albicans is the most prevalent opportunistic fungal pathogen in humans causing superficial and serious systemic infections. The infection process can be divided into three stages: adhesion, invasion, and host cell damage. To enhance our understanding of these C. albicans infection stages, this study aimed to predict phenotype-associated genes involved during these three infection stages and their roles in C. albicans–host interactions. In light of the principles that proteins that lie closer to one another in a protein interaction network are more likely to have similar functions, and that genes regulated by the same transcription factors tend to have similar functions, a cellular network approach was proposed to predict the phenotype-associated genes in this study. A total of 4, 12, and 3 genes were predicted as adhesion-, invasion-, and damage-associated genes during C. albicans infection, respectively. These predicted genes highlight the facts that cell surface components are critical for cell adhesion, and that morphogenesis is crucial for cell invasion. In addition, they provide targets for further investigations into the mechanisms of the three C. albicans infection stages. These results give insights into the responses elicited in C. albicans during interaction with the host, possibly instrumental in identifying novel therapies to treat C. albicans infection