Penetration of Different Kinds of Peptides or Collagen Through the Intestinal Membrane / 体力科学

Penetration of different kinds of peptides or collagen peptide through the intestinal membrane was studied in two experiments using an<I>in vitro</I>rat everted intestine penetration model. In Study 1, twelve 11-wk-old rats (Wistar strain) were randomly divided into two groups and penetration of whey peptide (n=6) and soy peptide (n=6) through the intestinal membrane was compared. In Study 2, fourteen 11-wk-old rats (Wistar strain) were divided into a control group (n=7) and a training group (treadmill running at a speed of 20-35 m/min for 15 mm day, 5 days wk for 4 wk n=7), and penetration of collagen peptide through the intestinal membrane was investigated in the two groups. In Study 1, the quantity of whey peptide that penetrated through the intestinal membrane was significantly greater than that of soy peptide (P<0.01) . In Study 2, body weight was significantly lower in the training group than in the control group except during 12 and 12.5 wk of age (13.5 wk ; P<0.01, others; P<0.05) . The weights of heart, kidney, and spleen were significantly increased, and the weight of fat was significantly decreased in the training group compared to the control group (P<0.05, P<0.05, P<0.01, P<0.05, respectively) . In both groups, a portion of collagen peptide penetrated through the intestinal membrane; but there was no significant difference in quantity between the two groups. In conclusion, the inhibition of weight gain in the training group was possibly caused by decreased feeding from lack of appetite with enforced exercise. These findings suggest that whey peptide penetrated through the intestinal membrane in greater quantities than soy peptide, and collagen peptide is not affected by enforced exercise.

Effect of muscle contraction type and speed on tissue oxygen dynamics in the M. vastus medialis during repeated knee extension exercise / 体力科学

The purpose of this study was to analyze the relationship between activity pattern and temporal changes in the oxygen dynamics of human femoral medial vastus muscles. Oxygen dynamics were evaluated from the surface of the body by near-infrared spectroscopy (NIRS) . Arterial occlusion tests were performed in the femoral region at a cuff pressure of 300 mmHg. Exercise type and speed were controlled by CYBEX 6000. The exercise types examined were concentric contraction (CON) and eccentric contraction (ECC) . The 3 angular velocities of 90, 120 and 180 degrees were used as the exercise speeds. Exercise was performed continuously 60 times at maximum effort. The subjects were 7 healthy males with a mean age of 19.6±0.5 years. A transient decrease in oxygen concentration was observed during circulatory occlusion ; and rapid hyperemia occurred immediately after the removal of pressure. Oxygen concentration peaked above the control level and then returned to the initial level. In the CON exercise, the initial decrease in oxygen concentration was the largest at CON 90, and a gradual increase in oxygen concentration was clearly observed during exercise. In the recovery stage, after exercise at CON 90, 120 and 180, oxygen concentration exceeded the control level before exercise, then peaked and returned to the initial level. In the ECC exercise, an initial decrease in oxygen concentration was similar to that in the CON exercise, but a gradual increase in oxygen concentration was not observed during the exercise ; nor did oxygen concentration exceed the control level in the recovery stage after the exercise.<BR>These results indicate that an increase in oxygen level after the removal of arterial occlusion, during and after the CON exercise was much higher than the control level before the exercise, sug-gesting the involvement of reactive hyperemia and exercise hyperemia.

Magnetic Resonance Imaging as an Index of Muscle Activation During Uphill and Downhill Running / 体力科学

The purpose of this study was to investigate the usage of the lower limb muscles (quadriceps femoris : QF, m. vastus lateralis : VL, m. rectus lemons : RF, m. vastus medialis : VM, m. vastus intermidialis : VI, hamstring : HM, m. gastrocnemius : UN, tihialis anterior : TA) and blood lactic acid concentration during uphill ( : UR +5 %) and downhill running ( : DR - 5 %) . We used magnetic resonance imaging (MRI) as one of the major indices. Seven healthy male volunteers participated in this study. T 2-weighted MR imaging, muscle surface temperature and blood lactic acid concentration were measured before and after UR and DR. In MRI imaging, the T2 value was defined as the area in which a high signal appeared after exercise.<BR>The value of the blood lactic acid concentration of UR was higher than that of DR (p<0.001) . After DR, the muscle surface temperature of RF was lower in comparison with other muscles (p< 0.05) . After UR, the T2 value of RF (p<0.05), HM (p<0.01) and UN (p<0.05) was higher than after DR exercise. During UR, a positive correlation (r=0.818) existed between the T 2 value of GN and blood lactic acid concentration (P<0.05) . During DR, a positive correlation (r=0.739) was also observed between the T 2 value of QF and blood lactic acid concentration (p<0.05) .<BR>From these results, we conclude that (1) the pattern of usage of lower limb muscles differs during UR and DR, (2) the most mobilized muscles in the lower limbs for UR are GN and HM, and (3) the most mobilized muscle in the lower limbs for DR is QF, respectively. These findings show that different exercises affect the blood lactic acid concentration differently.

The combined effects of strenuous exercise and sleep disturbance on cells in bronchoalveolar lavage fluids in mature rats / 体力科学

Phagocytic cells, polymorphonuclear leucocytes and macrophages, play an important role in non-specific cellular immunity, which is the first line of defense against infectious diseases. The purposes of this study were to clarify the combined effects of forced exercise and sleep disturbance on non-specific cellular immunity in mature rats, and to compare the effects between forced and voluntary exercise. Non-specific cellular immunity represented by the yield of cells from bronchoalveolar lavage and the superoxide-generating capacity of alveolar macrophages was investigated using mature rats.<BR>Male Wistar rats (11 weeks old) were divided into 5 groups:<BR>1) Training group ; exercised on a treadmill at a belt speed of 35 m/min for 15 min/day, <BR>2) Jet Lag group ; disturbance of the sleep cycle by day/night time shifts at 2-week intervals, <BR>3) Training+ Jet Lag (T + J) group ; exercised on a treadmill with sleep disturbance, a model identified by our research group to simulate chronic fatigue, 4) Voluntary group ; housed with running wheels, and 5) Control group ; housed under sedentary conditions.<BR>Body weight and food consumption measured during the experimental period showed coincidental changes. After 6 weeks of the experiment, the rats were sacrificed at the age of 17 weeks. Negative effects on non-specific cellular immunity were observed in the training group, and the rats were also slightly affected by sleep disturbance (Jet Lag group) . These negative effects seemed to be cumulative in the T+J group. In contrast, significant positive effects were observed in the voluntary group.<BR>These results suggest that stress, forced exercise and sleep disturbance negatively affect non-specific cellular immunity, and that voluntary exercise is able to enhance immunity even if it is started after maturation.

A study on serum enzyme activity levels and subjective fatigue scores in university ekiden runners / 体力科学

The principal objective of this paper is basic research on the development of an easy and rapid method to estimate physical fatigue levels. The focus of the research is to determine chronically fatigued conditions at an early stage for the prevention of chronic fatigue. Special attention was given to overtraining as one form of chronic fatigue in this paper. Long-distance runners representatives of a university in Tokyo nominated for Hakone-Ekiden were recruited as subjects. Examinations with informed consent were carried out on a once a month basis during 8 months and included the following; 1) physical characteristics ; body weight and body fat weight, 2) serum-biochemical test ; 6 parameters by the dry-chemistry method and the traditional method, 3) subjective fatigue levels ; the questionnaire of subjective symptom authorized by the Japan association of industrial health and the profile of mood state (POMS) . In this paper, data obtained from 19 male runners attending all 8 examinations were statistically analyzed.<BR>Serum parameters obtained by the dry-chemistry method, an easy and rapid method which provides clinical values on site, showed significant correlations with the traditional method.<BR>No correlation was observed between subjective fatigue scores and serum enzyme activity levels which were used as markers for estimation of physical fatigue levels in this study, however, monthly changes of enzyme levels and fatigue scores from July to August seemed to correlate in almost subjects. In contrast, using data obtained in the entire exprimental period, there was no relationship between the monthly changes of enzyme levels and fatigue scores. The results may indicate that some subjects exhibit gaps between physical fatigue and feelings of fatigue.<BR>The above mentioned results suggest that measurements of serum enzyme activity levels using the dry-chemistry method are a useful indicator for the prevention of overtraining.