Prevention of perceptual-motor decline by branched-chain amino acids, arginine, citrulline after tennis match.

Perceptual-motor performance in prolonged tennis matches may be affected by central fatigue. The purpose of this study was to investigate the supplementation of branched-chain amino acids (BCAA), arginine, and citrulline on tennis-specific perceptual-motor performance after a simulated match. Nine male tennis players consumed 0.17 g/kg BCAA, 0.05 g/kg arginine, and 0.05 g/kg citrulline (AA trial), or placebo (PB trial) 1 h before the match. In the perceptual-motor performance test before and after the match, the subjects hit balls to the opposite direction of the examiner's movement. The AA trial showed significantly higher rate of correct direction than the PB trial after the match (AA trial: 93.63 ± 1.28%, PB trial: 69.09 ± 2.40%). The AA trial also demonstrated significantly higher post-match accuracy and consistency than the PB trial. The AA trial showed significantly lower heart rate and ratings of perceive exertion during the match, concurrently with a significantly lower plasma total tryptophan/BCAA ratio. Similar post-match plasma NH3 concentrations were found in both trials while the AA trial was significantly higher in NOx concentration. This study suggested that the supplementation could prevent the decline in perceptual-motor performance through alleviation of central fatigue by BCAA and prevention of excess hyperammonemia by arginine and citrulline.

Altered p-JAK1 expression is associated with estrogen receptor status in breast infiltrating ductal carcinoma.

The mammalian Janus kinase (JAK) family consists of four members, namely JAK1, JAK2, JAK3 and TYK2, which play a critical role in cytokine/growth factor signaling and is increasingly associated with human cancers. Aberrant activation of these non-receptor tyrosine kinases may contribute to carcinogenesis. Herein, we focused on exploring the potential role of p-JAK1 in breast cancer. The expression profiles of p-JAK1 were analyzed in 68 pairs of cancer and non-cancer breast tissues from the same infiltrating ductal carcinoma case by using immunoblotting technique. The results obtained were further correlated with clinicopathological characteristics. Intriguingly, p-JAK1 expression was decreased in 55.9% of breast cancer tissues as compared to the matched non-cancer tissues. Further immunohistochemistry study showed an intense p-JAK1 staining predominantly in adjacent normal breast tissues but not the matched cancer lesions. Decreased p-JAK1 expression in breast cancer tissues was significantly correlated with positive estrogen receptor (ER) status and increased tumor size (p=0.010 and 0.009). We also found that p-JAK1 expression was high in ERalpha-negative breast cancer cell lines but was low in ERalpha-positive breast cell lines. Transfection of ERalpha-positive MCF-7 cells with an ERalpha-specific siRNA upregulated the expression of p-JAK1. In summary, our results indicated that an altered p-JAK1 expression might be involved in the development of breast infiltrating ductal carcinoma in an ERalpha-related manner.

Measurement of unbound caffeic acid in rat blood by on-line microdialysis coupled with liquid chromatography and its application to pharmacokinetic study.

To monitor the levels of caffeic acid in rat blood, an on-line microdialysis system coupled with liquid chromatography was developed. The microdialysis probe was inserted into the jugular vein/right atrium of male Sprague-Dawley rats. Caffeic acid (100 mg/kg, i.v.) was then administered via the femoral vein. Dialysates were automatically injected onto a liquid chromatographic system via an on-line injector. Samples were eluted with a mobile phase containing methanol-100 mM monosodium phosphoric acid (35:65, v/v, pH 2.5). The UV detector wavelength was set at 320 nm. The detection limit of caffeic acid was 20 ng/ml. The in vivo recoveries of the microdialysis probe for caffeic acid at 0.5 and 1 microg/ml were 48.34+/-2.68 and 47.64+/-3.43%, respectively (n=6). Intra- and inter-assay accuracy and precision of the analyses were < or = 10% in the range of 0.05 to 10 microg/ml. Pharmacokinetics analysis of results obtained using such a microdialysis-chromatographic method indicated that unbound caffeic acid in the rat fitted best to a biexponential decay model.