Overexpression of Leptin Reduces the Ratio of Glycolytic to Oxidative Enzymatic Activities without Changing Muscle Fiber Types in Mouse Skeletal Muscle

Increased spontaneous locomotive activity and oxygen consumption have been reported in transgenic mice overexpressing leptin in the liver. In the present study, we examined whether the overexpression of leptin altered glycolytic and oxidative metabolic enzymatic activities as well as the composition of myosin heavy chain (MHC) isoforms in skeletal muscle. Enzymatic activities of lactate dehydrogenase (LDH) and citrate synthase (CS) were quantified in gastrocnemius muscle (GAS) and the red portion of tibialis anterior muscle (TA) from leptin transgenic (Tg) mice and non-Tg mice. The composition of MHC isoforms was measured in soleus muscle (SOL) and extensor digitorum longus muscle (EDL) from the two groups. In red TA, LDH-to-CS ratio was significantly lower in Tg than in non-Tg (p=0.014), whereas no significant change was observed in GAS. The composition of MHC isoforms was not significantly different in SOL or EDL between Tg and non-Tg groups. Our data indicate that chronic overexpression of leptin reduces the ratio of glycolytic to oxidative capacity without changing muscle fiber types particularly in red muscles. This metabolic change may contribute to the increased spontaneous locomotive activity and oxygen consumption in Tg mice reported previously

Anthropometric, Spirometric, and Physiologic Comparisons of Migrant Japanese

Anthropometric measurements, pulmonary function, and maximal oxygen uptake determinations were obtained on 45 healthy males. The subjects were assigned to three groups of 15 each, according to racial origin and generation in a particular environment. These groups were Issei (native Japanese), X age = 24.4 years; Sansei (third-generation Japanese-Ameri­cans), X age = 19.9 years; and Caucasian (white Americans), X age = 26.7 years. The stature of Issei and Sansei was smaller than that of Caucasians. There were no differences in calculated percentage of body weight due to fat or estimated caloric intakes. Sansei had larger chest and wrist widths and thigh circumferences than those of the Issei, and smaller than or equal to those of the Caucasians. These structural differences were linked with pulmonary function and maximal oxygen uptake differences between the three groups. Comparison of the obtained data with previous data indicated a maximal average size of the Japanese to be 169 cm, which is genetically controlled. Environmental factors appeared to affect both structural differences and pulmonary dimension differences. When structural differences were considered, the Caucasians were found to be more physically fit than the Sansei, who in turn were fitter than the Issei. These differences can be explained by activity patterns

Anthropometric, Spirometric, and Physiologic Comparisons of Migrant Japanese

Anthropometric measurements, pulmonary function, and maximal oxygen uptake determinations were obtained on 45 healthy males. The subjects were assigned to three groups of 15 each, according to racial origin and generation in a particular environment. These groups were Issei (native Japanese), X age = 24.4 years; Sansei (third-generation Japanese-Ameri­cans), X age = 19.9 years; and Caucasian (white Americans), X age = 26.7 years. The stature of Issei and Sansei was smaller than that of Caucasians. There were no differences in calculated percentage of body weight due to fat or estimated caloric intakes. Sansei had larger chest and wrist widths and thigh circumferences than those of the Issei, and smaller than or equal to those of the Caucasians. These structural differences were linked with pulmonary function and maximal oxygen uptake differences between the three groups. Comparison of the obtained data with previous data indicated a maximal average size of the Japanese to be 169 cm, which is genetically controlled. Environmental factors appeared to affect both structural differences and pulmonary dimension differences. When structural differences were considered, the Caucasians were found to be more physically fit than the Sansei, who in turn were fitter than the Issei. These differences can be explained by activity patterns

Heart Rate Responses of Fire-men to Actual Fire-fighting and Their Endurance Capacity

http://ci.nii.ac.jp/naid/11000664561

Tee-batting skills in relation to ground reaction forces

The purpose of this study was to investigate tee-batting skills in relation to ground reaction forces. Eithteen batters tried seven swings on the force platform recording three-dimensional kinetic data. A video camera (60 fps) was used to measure ball velocity and swing velocity. The following results were obtained. 1) A statistically significant correlation was observed between the swing velocity and the swing time. 2 Statistically significant correlations were observed between the swing velocity and the anteroposterior forces during backward swing phase, the mean power calculated from the anteroposterior force during forward swing phase. 3) Statistically significant correlations were obtained between the swing velocity, the ball velocity and the mediolateral distance of the CG of the body from the starting position during backward swing phase. 4) The swing velocity and the ball velocity significantly correlated with the mediolateral distance of the CG of the body between the starting phase and the impact phase. 5) Coefficient of variations (cv) of the vertical forces during backward swing phase and the mean power calculated from the vertical force significantly correlated with cv of the swing velocity. CV of the vertical power of the CG of the body significantly correlated with cv of the ball velocity. These findings suggest that the batter should move the body toward the opposite side of the ball and the anterior direction just before the starting phase of the forward swing to obtain the high swing velocity. The result also suggests that the batter should control the vertical movement during backward and forward swing to obtain the high reproducibility of batting.http://ci.nii.ac.jp/naid/11000191893