Enteritis is a serious problem for patients having received abdominal radiation. This study was to investigate whether zinc affected intestinal injury induced by the radiation. ICR mice were divided randomly into three groups and treated with one of three different compounds. Two of the compounds contained zinc (gluconate and amino acid chelated with bovin prostate extract) and one was water. One week after receiving the treatment, they were irradiated with 6 or 10 Gy at the abdominal region. One, 2, and 4 weeks after the irradiation the animals were sacrificed to examine the histological changes in the intestinal mucosa. The apoptotic cell numbers were found to be significantly higher after irradiation. The number of the apoptotic cells increased with increasing radiation doses. In this study we found that zinc appears to have the capability to lower the occurrence of apoptosis in the intestinal mucosa, thus protecting intestinal mucosa from injuries. Based on this finding, it would be reasonable to suggest that zinc could be used as food supplements in patients with cancer receiving radiotherapy in a hope to reduce radiation induced toxicity.
Authors:T. Yano, R. Afroundeh, R. Yamanaka, T. Arimitsu, C.S. Lian, K. Shirakawa and T. Yunoki
The purpose of the present study was to examine 1) whether O2 uptake (V̇O2) oscillates during light exercise and 2) whether the oscillation is enhanced after impulse exercise. After resting for 1 min on a bicycle seat, subjects performed 5-min pre-exercise with 25 watts work load, 10-s impulse exercise with 200 watts work load and 15-min post exercise with 25 watts work load at 80 rpm. V̇O2 during pre-exercise significantly increased during impulse exercise and suddenly decreased and re-increased until 23 s after impulse exercise. In the cross correlation between heart rate (HR) and V̇O2 after impulse exercise, V̇O2 strongly correlated to HR with a time delay of −4 s. Peak of power spectral density (PSD) in HR appeared at 0.0039 Hz and peak of PSD in V̇O2 appeared at 0.019 Hz. The peak of the cross power spectrum between V̇O2 and HR appeared at 0.0078 Hz. The results suggested that there is an oscillation in O2 uptake during light exercise that is associated with the oscillation in O2 consumption in active muscle. The oscillation is enhanced not only by change in O2 consumption but also by O2 content transported from active muscle to the lungs.
Authors:T Yano, W Widjaja, K Shirakawa, C-S Lian, Z Xiao and T Yunoki
The purpose of this study was to determine whether tissue oxygen indices (TOIs) in two muscle groups oscillated and were synchronized in repetition of impulse exercise with high intensity. Five impulse exercises of 400 watts for 10 s were repeated with intervals of 6 min. During this period, TOI was determined by near-infrared spectroscopy in the vastus lateralis and gastrocnemius muscles. TOIs in the two muscles oscillated at rest. The TOIs rapidly decreased during each impulse exercise and then recovered and overshot after each impulse. The TOIs oscillated during each interval period. During this test period, coherent and phase differences were determined. There was high coherence between TOIs in the two muscles with a peak value at 0.019 Hz. There was a phase difference of −45 ± 32.4 degrees between TOIs in the two muscles. This phase difference corresponded to about 6 s in time scale. It seemed from this time delay that impulse exercise was not a trigger factor for the starting point of TOIs in the two muscles. It has been concluded that TOIs oscillate and are synchronized between two muscles in repetition of impulse exercise with high intensity.
Authors:T Yano, R Afroundeh, K Shirakawa, C-S Lian, K Shibata, Z Xiao and T Yunoki
The purpose of the present study was to examine how oscillation of tissue oxygen index (TOI) in non-exercising exercise is affected during high-intensity and low-intensity exercises. Three exercises were performed with exercise intensities of 30% and 70% peak oxygen uptake (Vo2peak) for 12 min and with exercise intensity of 70% Vo2peak for 30 s. TOI in non-exercising muscle (biceps brachii) during the exercises for 12 min was determined by nearinfrared spectroscopy. TOI in the non-exercising muscle during the exercises was analyzed by fast Fourier transform (FFT) to obtain power spectra density (PSD). The frequency at which maximal PSD appeared (Fmax) during the exercise with 70% Vo2peak for 12 min (0.00477 ± 0.00172 Hz) was significantly lower than that during the exercise with 30% Vo2peak for 12 min (0.00781 ± 0.00338 Hz). There were significant differences in blood pH and blood lactate between the exercise with 70% Vo2peak and the exercise with 30% Vo2peak. It is concluded that TOI in nonexercising muscle oscillates during low-intensity exercise as well as during high-intensity exercise and that the difference in Fmax between the two exercises is associated with the difference in increase in blood lactate derived from the exercise.