In order to predict airflow and suspended substance concentration around a human body, we developed a geometric model of the human form and generated grids around it for Computational Fluid Dynamics (CFD). According to a CFSV model proposed by us we made a domain that included a geometric human model and generated the grids within this domain. By using this model with the grids and the developed CFD program, it is possible to simulate the airflow and the transfer of a suspended substance around the body. The simulated airflow provided a different velocity profile for each region of the body due to the characteristics of the body shape. The simulated distribution of the suspended substance concentration demonstrates how usable the present model is for quantifying a substance in any exposed region of the body.
Previous studies have shown that mortality from cardiovascular diseases in fishing villages was lower than that in farming villages. In contrast, few reports on the population living in a tourist village have appeared. Then, we report here the characteristic features of a tourist town, and that in fishing and farming towns. The rural farming town in Gunma prefecture had a population of 15100. The population working in the primary industry was 17.1%, and the farming population was 17.0%. The fishing town in Shizuoka prefecture had a population of 11700. The population working in the primary industry was 11.0%, and the fishing population was 10.2%. The rural tourist town in Shizuoka prefecture had a population of 17800. The population working in the tertiary industry was 60.2%, and the wholesaling or retailing population was 16.6%. Standardized mortality ratios of cardiovascular diseases in the tourist town reported by Shizuoka health officials were higher than the fishing town. The rate of participation at ages of 50–59 years for the basic health examination in the tourist town was lower than the fishing and the farming towns. From the results of the health examination of residents at ages of 50–59 years, the high prevalence of obesity and hypertension in men and high prevalence of hypertension in women were found in the tourist town. In the tourist town, self-employed women at ages of 50–59 years had irregular time of meals and insufficient care of diet in comparison with employed women. Furthermore, the prevalence of hypertension in self-employed women was also higher than that of employed women. We could suggest that health status in communities might be associated with job-related factors.
The effect of exercise practice on the radius bone mineral density (BMD) was investigated on 480 women at the age of perimenopause and later. The BMD at the 1/3 distal site of the radius on a non-dominant hand was measured using the Dual Energy X-ray Absorptiometry method. The subjects were divided into group E with regular exercising and group C without regular exercising. The difference of mean radius BMD values was not statistically significant between groups E and C. Each of the groups E and C was further classified into a perimenopause group and groups with stratified postmenopausal years (postmenopausal years less than 5, less than 10 and more than 10). Then, the mean radius BMD value of the perimenopause subgroup was taken as 100% for each of the groups E and C, and the relative radius BMD values of subgroups were compared between groups E and C. The relative BMD values for the subgroup of postmenopausal years more than 10 were higher in E group than those in C group, while no difference was observed in below postmenopausal 10 years between the two groups. To clarify the BMD difference among exercise events, group E was further divided into the following three subgroups: the subgroup practising events which give high-impact to arm (HI group), such as tennis, ping-pong, golf and volleyball, the subgroup practising swimming (SW group), and the subgroup practising events which give low-impact to arm (LI group), such as walking, running, aerobic dance and light gymnastics. No significant differences were observed in BMD values among the above sports event-stratified subgroups when postmenopausal years were less than 10 years, but the relative BMD values for the subgroup of postmenopausal years more than 10 were higher in HI and LI group than those in control group. These results suggest the possibility that exercise practice suppresses a postmenopausal decline in bone density for preventing osteoporosis from developing.
We investigated the effects of cyclooxigenase-2 (cox-2) on fracture healing. After closed non-displaced fractures were created at the middle of both femoral shafts in 12-week-old Wister rats, a cox-2 specific inhibitor, etodolac (20 mg/day; intra-peritoneal) was administered every day for three weeks (E group). Bone union and callus formation were evaluated by weekly radiographs. Three weeks after surgery, the mechanical strength of the fractured femur was evaluated by a three-point-bending test. These results were compared with those of a vehicle control group (V group). The fracture healing score on radiographs in the E group three weeks after the surgery was 3.3+/−0.9, and in the V group it was 5.8+/−1.5, indicating that fracture healing was significantly poorer in the E than the V group (p<0.05). From the three point bending test, the ultimate strength and stiffness of etodolac-treated fractured femurs were shown to be significantly lower than those in vehicle control group (p<0.05). Mechanically, femurs of etodolac treated rats were weaker than those of control rats. Thus, it was concluded that etodolac, a cox-2 specific inhibitor, inhibited fracture healing.
To evaluate the difference of ventilatory and gas exchange response differences between arm and leg exercise, six healthy young men underwent ramp exercise testing at a rate of 15 W·min−1 on a cycle ergometer separately under either spontaneous (SPNT) or fixed (FIX) breathing modes, respectively. Controlled breathing was defined as a breathing frequency (fb; 30 breaths·min−1) which was neither equal to, nor a multiple of, cranking frequency (50 rev·min−1) to prevent coupling of locomotion and respiratory movement, i.e., so-called locomotor-respiratory coupling (LRC). Breath-by-breath oxygen uptake (VO2), ventilation (VE), CO2 output (VCO2), tidal volume (VT), fb and end-tidal PCO2 (PETCO2) were determined using a computerized metabolic cart. Arm exercise engendered a higher level of VO2 at each work rate than leg exercise under both FIX and SPNT conditions. However, FIX did not notably affect the VO2 response during either arm or leg exercise at each work rate compared to SPNT. During SPNT a significantly higher fb and lower PETCO2 during arm exercise was found compared with leg exercise up to a fb of 30 breaths·min−1 while VE and VT were nearly the same. During fixed breathing when fb was fixed at a higher rate than during SPNT, a significantly lower PETCO2 was observed during both exercise modes. These results suggest that: 1) FIX breathing does not affect the VO2 response during either arm or leg exercise even when non-synchronization between limb locomotion movement and breathing rate was adopted; 2) at a fb of 30 breaths·min−1 FIX breathing induced a hyperventilation resulting in a lower PETCO2 which was not associated with the metabolic rate during either arm or leg exercise, showing that VE during only leg exercise under the FIX condition was significantly higher than under the SPNT condition.
Time-resolved 31-phosphorus nuclear magnetic resonance spectroscopy (31P-MRS) of the biceps femoris muscles was performed during exercise and recovery in six healthy sedentary male subjects (maximal oxygen uptake; 46.6±1.7 (SEM) ml·kg−1·min−1), 5 male sprinters (56.2±2.5), and 5 male long-distance runners (73.6±2.2). Each performed 4 min of knee flexion exercises at absolute values of 1.63 W and 4.90 W, followed by 5 min of recovery in a prone position in a 2.1 T superconducting magnet with a 67 cm bore. 31P-MRS spectra were recorded every 12.8 s during the rest-exercise-recovery sequence. Computer-aided contour analysis and pixel imaging of phosphocreatine peaks (PCr) and inorganic phosphate (Pi) were performed. The work loads in the present study were selected as mild exercise (1.63 W) and heavy exercise (4.90 W), corresponding to 18–23% and 54–70% of maximal exercise intensity. Long-distance runners showed a significantly smaller decrement in PCr and less acidification at a given exercise intensity compared to those shown by sedentary subjects. The transient responses of PCr and Pi during recovery were characterized by first-order kinetics. After exercise, the recovery rates of PCr and Pi were significantly faster in long-distance runners than in sedentary subjects (P<0.05). Since it is postulated that PCr resynthesis is controlled by aerobic metabolism and mitochondrial creatine kinase, it is suggested that the faster PCr and Pi recovery rates and decreased acidification seen inlong-distance runners during and after exercise might be attributed to their greater capacity for aerobic metabolism.
We previously reported that intragastric administration of cysteine could be beneficial to prevent unweighting-induced ubiquitination and degradation of muscle protein in association with redox regulation [Ikemoto et al., Biol. Chem., 383 (2002), 715–721]. In this study, we investigated whether vitamin E, another potent antioxidative nutrient, also had beneficial effects on the muscle protein catabolism. However, daily intragastric supplementation of 1.5 or 15 mg/rat of α-tocopherol did not prevent weight loss of hindlimb skeletal muscle in tail-suspended rats. To elucidate the reason for the non-effectiveness of vitamin E, we further examined concentrations of oxidative stress markers, ubiquitination of muscle proteins and fragmentation of myosin heavy chain in gastrocnemius muscle of rats daily treated with 15 mg of α-tocopherol. Unexpectedly, vitamin E increased concentrations of glutathione disulfide and thiobarbituric acid-reactive substance and decreased glutathione level in the muscle, compared with those of vehicle treatment, indicating that vitamin E enhanced unweighting-induced oxidative stress in skeletal muscle. The vitamin E supplementation did not suppress the ubiquitination of muscle proteins and fragmentation of myosin heavy chain caused by tail-suspension. Our results suggest that supplementation of a relative high dose of vitamin E could not inhibit ubiquitin-dependent degradation of muscle protein in tail-suspended rats possibly due to its prooxidant action.