The present study was designed to assess the effects of dietary leucine supplementation on muscle protein synthesis and whole body protein kinetics in elderly individuals. Twenty healthy male subjects (70 ± 1 years) were studied before and after continuous ingestion of a complete balanced diet supplemented or not with leucine. A primed (3.6 μmol kg −1 ) constant infusion (0.06 μmol kgphenylalanine was used to determine whole body phenylalanine kinetics as well as fractional synthesis rate (FSR) in the myofibrillar fraction of muscle proteins from vastus lateralis biopsies. Whole body protein kinetics were not affected by leucine supplementation. In contrast, muscle FSR, measured over the 5-h period of feeding, was significantly greater in the volunteers given the leucine-supplemented meals compared with the control group (0.083 ± 0.008 versus 0.053 ± 0.009% h −1 , respectively, P < 0.05). This effect was due only to increased leucine availability because only plasma free leucine concentration significantly differed between the control and leucine-supplemented groups. We conclude that leucine supplementation during feeding improves muscle protein synthesis in the elderly independently of an overall increase of other amino acids. Whether increasing leucine intake in old people may limit muscle protein loss during ageing remains to be determined.

Fermentative bacteria can potentially be utilized to detoxify corn silage contaminated by Fusarium toxins. The objective of the present study was to test a large number of these bacteria for their ability to bind and/or biotransform deoxynivalenol (DON), zearalenone (ZEN) and fumonisins B(1) and B(2) (FB(1), FB(2)) in conditions simulating corn silage. A total of 202 strains were screened in contaminated, pH 4, corn infusion inoculated with 5 x 10(8) CFU ml(-1). Eight Lactobacilli and three Leuconostoc biotransformed ZEN into alpha-zearalenol, but no biotransformation was detected for DON and fumonisins. In contrast, most strains were capable of binding Fusarium toxins. The most effective genera were Streptococcus and Enterococcus, capable of binding up to 33, 49, 24 and 62% of DON, ZEN, FB(1) and FB(2), respectively. The ability to bind Fusarium toxins seems to be a common property of fermentative bacteria and could help to decrease their toxicity in animals.

Background/AimsHuman gut microbiota harbors numerous metabolic properties essential for the host's health. Increased intestinal transit time affects a part of the population and is notably observed with human aging, which also corresponds to modifications of the gut microbiota. Thus we tested the metabolic and compositional changes of a human gut microbiota induced by an increased transit time simulated in vitro. MethodsThe in vitro system, Environmental Control System for Intestinal Microbiota, was used to simulate the environmental conditions of 3 different anatomical parts of the human colon in a continuous process. The retention times of the chemostat conditions were established to correspond to a typical transit time of 48 hours next increased to 96 hours. The bacterial communities, short chain fatty acids and metabolite fingerprints were determined. ResultsIncrease of transit time resulted in a decrease of biomass and of diversity in the more distal compartments. Short chain fatty acid analyses and metabolite fingerprinting revealed increased activity corresponding to carbohydrate fermentation in the proximal compartments while protein fermentations were increased in the lower parts. ConclusionsThis study provides the evidence that the increase of transit time, independently of other factors, affects the composition and metabolism of the gut microbiota. The transit time is one of the factors that explain some of the modifications seen in the gut microbiota of the elderly, as well as patients with slow transit time.

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In this work we have optimized the analysis of 18 human corticosteroids, some endogenous (tetrahydrocortisol, tetrahydrocortisone, cortisol, and cortisone) and others synthetic (betamethasone, budesonide, cortisone acetate, desonide, dexamethasone, dexamethasone acetate, flunisolide, fluocinolone acetonide, halcinonide, methylprednisolone, prednisolone, prednisone, triamcinolone, and triamcinolone acetonide). Three analytical techniques were developed: ELISA, gas chromatography coupled with mass spectrometry (GC-MS), and liquid chromatography coupled with mass spectrometry (LC-MS). Several sample-preparation methods were optimized for each technique and enabled compounds of interest to be extracted from small urine samples (several mL). The results enabled us to assess the possibilities and the sensitivity of each technique for application to doping tests.

Deep brain stimulation in patients with PD affects EGP glucose disposal, suggesting that a cross talk between the central nervous system and peripheral tissues may regulate glucose homeostasis.

A method of detecting and quantifying dehydroepiandrosterone (DHEA) sulfate, corticosteroids, and androgens has been developed. All of the compounds were first extracted from urine using solid phase extraction (SPE), enzymatically hydrolyzed, and separated into three samples using a second SPE. A DHEA sulfate sample was acetylated and re-extracted using SPE for purification before analysis. Corticosteroid samples were oxidized and re-extracted using liquid/liquid extraction for analysis. Androgen samples were acetylated and re-extracted using SPE prior to analysis. The extraction and analysis methods were investigated and optimized. Analyses were performed with gas chromatography/mass spectrometry (GC/MS) and gas chromatography/flame ionization detection (GC/FID). The entire procedure was then applied to the study of urine profiles of healthy volunteers and patients treated with corticosteroids. The results showed that the quantities of androgens found in patient urines were lower than in those of healthy volunteers. In addition, other metabolites were detected in patient urines.

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