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Protective Capacity (protective + capacity)
Selected AbstractsEffects of yeast probiotic formulation on viability, revival and protection against infection with Salmonella enterica ssp. enterica serovar Typhimurium in miceLETTERS IN APPLIED MICROBIOLOGY, Issue 6 2009F.S. Martins Abstract Aims:, To compare the effects of five yeast probiotic formulations on viability, revival and washout kinetic in the digestive tract of mice, and the protection against an experimental infection with Salmonella enterica serovar Typhimurium. Methods and Results:, The number of viable cells in five commercial probiotic products codified as A, B, C and D (Saccharomyces boulardii, lyophilized) and E (Saccharomyces cerevisiae, aqueous suspension) was determined, as well as revival and washout kinetic in mouse intestine. Protective capacity was evaluated by survival rate and histopathology of liver and intestine of mice treated with each product and then challenged with Salm. Typhimurium. Conclusions:, Product A contained the highest number of viable cells and, fed to mice, gave the highest counts of viable yeasts and the longest persistence in faeces. Probably as a consequence, the highest survival and protection of intestinal and hepatic tissues were observed when product A was used for mouse treatment. Product E showed low counts in the formulation and was not recovered from mouse intestine. Significance and Impact of the Study:, Formulation (lyophilization or aqueous suspension) is an important factor for revival and survival of a probiotic product in vivo and consequently for its protective properties. [source] Initial short-term intensive insulin therapy as a strategy for evaluating the preservation of beta-cell function with oral antidiabetic medications: a pilot study with sitagliptinDIABETES OBESITY & METABOLISM, Issue 10 2010R. Retnakaran Aim: Studies evaluating the effects of oral antidiabetic drugs (OADs) on beta-cell function in type 2 diabetes mellitus (T2DM) are confounded by an inability to establish the actual baseline degree of beta-cell dysfunction, independent of the deleterious effects of hyperglycaemia (glucotoxicity). Because intensive insulin therapy (IIT) can induce normoglycaemia, we reasoned that short-term IIT could enable evaluation of the beta-cell protective capacity of OADs, free from confounding hyperglycaemia. We applied this strategy to assess the effect of sitagliptin on beta-cell function. Methods: In this pilot study, 37 patients with T2DM of 6.0 + 6.4 years duration and A1c 7.0 + 0.8% on 0,2 OADs were switched to 4,8 weeks of IIT consisting of basal detemir and premeal insulin aspart. Subjects achieving fasting glucose <7.0 mmol/l 1 day after completing IIT (n = 21) were then randomized to metformin with either sitagliptin (n = 10) or placebo (n = 11). Subjects were followed for 48 weeks, with serial assessment of beta-cell function [ratio of AUCCpep to AUCgluc over Homeostasis Model Assessment of Insulin Resistance (HOMA-IR) (AUCCpep/gluc/HOMA-IR)] on 4-h meal tests. Results: During the study, fasting glucagon-like-peptide-1 was higher (p = 0.003) and A1c lower in the sitagliptin arm (p = 0.016). Nevertheless, although beta-cell function improved during the IIT phase, it declined similarly in both arms over time (p = 0.61). By study end, AUCCpep/gluc/HOMA-IR was not significantly different between the placebo and sitagliptin arms (median 71.2 vs 80.4; p = 0.36). Conclusions: Pretreatment IIT can provide a useful strategy for evaluating the beta-cell protective capacity of diabetes interventions. In this pilot study, improved A1c with sitagliptin could not be attributed to a significant effect on preservation of beta-cell function. [source] Novel conjugate vaccine for the prevention of Pseudomonas aeruginosa infection in cystic fibrosis patientsDRUG DEVELOPMENT RESEARCH, Issue 8 2007Kelly L. Matson Abstract The published literature evaluating the safety and immunogenicity of the polyvalent O-polysaccharide-toxin A conjugate vaccine is reviewed. Primary immunization followed by annual booster significantly reduced the incidence of chronic Pseudomonas aeruginosa lung infections (particularly mucoid phenotype strains) and extended time to infection. The findings reflected lower frequency of P. aeruginosa in sputum/throat cultures and preservation of lung function. Additionally, studies indicated higher binding affinity of vaccine-induced anti-lipopolysaccharide (LPS) compared with infection-induced anti-LPS serum immunoglobulin G antibodies, suggesting protective capacity. P. aeruginosa prophylaxis with the conjugate vaccine in cystic fibrosis patients has proved safe and useful in preventing and delaying chronic lung infection. Drug Dev Res 68:512,521, 2007. © 2008 Wiley-Liss, Inc. [source] Monitoring of DNA breakage in embryonic stages of the African catfish Clarias gariepinus (Burchell, 1822) after exposure to lead nitrate using alkaline comet assayENVIRONMENTAL TOXICOLOGY, Issue 6 2008Alaa G. M. Osman Abstract Increasing lead contamination in Egyptian ecosystems and high lead concentrations in food items have raised concern for human health and stimulated studies on monitoring ecotoxicological impact of lead-caused genotoxicity. In this work, the alkaline comet assay was modified for monitoring DNA strand breakage in sensitive early life stages of the African catfish Clarias gariepinus. Following exposure to 100, 300, and 500 ,g/L lead nitrate, DNA strand breakage was quantified in embryos at 30, 48, 96, 144, and 168 h post-fertilization (PFS). For quantitative analysis, four commonly used parameters (tail % DNA, %TDNA; head % DNA, %HDNA; tail length, TL; tail moment, TM) were analyzed in 96 nuclei (in triplicates) at each sampling point. The parameter %TDNA revealed highest resolution and lowest variation. A strong correlation between lead concentration, time of exposure, and DNA strand breakage was observed. Here, genotoxicity detected by comet assay preceded the manifested malformations assessed with conventional histology. Qualitative evaluation was carried out using five categories are as follows: undamaged (%TDNA , 10%), low damaged (10% < %TDNA , 25%), median damaged (25 < %TDNA , 50%), highly damaged (50 < %TDNA , 75%), and extremely damaged (%TDNA > 75%) nuclei confirming a dose and time-dependent shift towards increased frequencies of highly and extremely damaged nuclei. A protective capacity provided by a hardened chorion is a an interesting finding in this study as DNA damage in the prehatching stages 30 h-PFS and 48 h-PFS was low in all treatments (qualitative and quantitative analyses). These results clearly show that the comet assay is a sensitive tool for the detection of genotoxicity in vulnerable early life stages of the African catfish and is a method more sensitive than histological parameters for monitoring genotoxic effects. © 2008 Wiley Periodicals, Inc. Environ Toxicol, 2008. [source] Nest protection in mallards Anas platyrhynchos: untangling the role of crypsis and parental behaviourFUNCTIONAL ECOLOGY, Issue 5 2008J. Kreisinger Summary 1The covering of clutches with nest material is generally considered to improve the thermal environment of developing embryos. Here we tested an alternative hypothesis: that this behaviour reduces the risk of clutch detection by predators and hence, fulfils a cryptic anti-predation function in a ground-nesting non-passerine bird, the mallard. In addition, we assess the anti-predation function of the direct presence of an incubating parent on the nest for the first time in a ground-nesting non-passerine bird. 2We compared predation rates of real mallard nests with two types of artificial clutches: (i) covered with nest material and (ii) uncovered. In addition, the cryptic effectiveness of nest material, female body presence, and uncovered clutch were assessed using a simulated search for nests on photographs by human volunteers. This allowed us to evaluate separately the impact of overall crypsis (covering of the clutch by nest material and colouration of the female feather) and the direct protective capacity of the incubating female. 3Our data demonstrate that in mallards, concealment of the clutch with nest material reduces the risk of nest predation. Although the incubating female seems to provide less effective crypsis to the nest than nest material alone, the presence of the female on the clutch enhanced nest survival, suggesting a significant anti-predation capacity of the incubating parent in this species. 4Contrary to some previous studies, the relative effects of crypsis and parental anti-predation behaviour on nest survival did not differ with respect to nest concealment by surrounding vegetation. [source] | |||||||||||||