Resistance exercise training and in vitro skeletal muscle oxidative capacity in older adults

Whether resistance exercise training (RET) improves skeletal muscle substrate oxidative capacity and reduces mitochondrial production of reactive oxygen species in older adults remains unclear. To address this, 19 older males (≥60 years) were randomized to a RET (n = 11) or to a waitlist control group (n = 8) that remained sedentary for 12 weeks. RET was comprised of three upper body and four lower body movements on resistance machines. One set of 8-12 repetitions to failure of each movement was performed on three nonconsecutive days/week. Improvements in chest press and leg press strength were assessed using a three-repetition maximum (3 RM). Body composition was assessed via dual energy X-ray absorptiometry. Muscle biopsies were obtained from the vastus lateralis muscle at baseline and at both 3 weeks and 12 weeks. Palmitate and pyruvate oxidation rates were measured from the (14)CO2 produced from [1-(14)C] palmitic acid and [U-(14)C] pyruvate, respectively, during incubation of muscle homogenates. PGC-1α, TFAM, and PPARδ levels were quantified using qRT-PCR Citrate synthase (CS) and β-HAD activities were determined spectrophotometrically. Mitochondrial production of reactive oxygen species (ROS) were assessed using the Amplex Red Hydrogen Peroxide/Peroxidase assay. There were no significant changes in body weight or body composition following the intervention. Chest press and leg press strength (3RM) increased ~34% (both P < 0.01) with RET There were no significant changes in pyruvate or fatty acid oxidation or in the expression of target genes with the intervention. There was a modest increase (P < 0.05) in βHAD activity with RET at 12 weeks but the change in CS enzyme activity was not significant. In addition, there were no significant changes in ROS production in either group following RET Taken together, the findings of this study suggest that 12 weeks of low volume RET does not increase skeletal muscle oxidative capacity or reduce ROS production in older adults.

High-performance liquid chromatographic determination of carbaryl and 1-naphthol in biological fluids

A simple and sensitive method for the simultaneous analysis of carbaryl and 1-naphthol in whole blood by reversed-phase high-performance liquid chromatography and fluorescence detection is described. Spiked blood (heparinized) containing an internal standard was hemolyzed and extracted with ethyl acetate. After centrifugation the extractant was removed and taken to dryness. Reconstitution and subsequent high-performance liquid chromatography-fluorescence analysis yielded linear standard curves for carbaryl and 1-naphthol. Linear response vs. concentration profiles were obtained for carbaryl and 1-naphthol extracted from buffer solutions as well. A simple chemical hydrolysis study of carbaryl is included to illustrate the effectiveness of the extraction procedure and assay.