Biomedical subjects
Publications and source records attributed to T Sadamoto.
A new instrument for percutaneous muscle biopsies is presented. It was tested in biopsies of the vastus lateralis, gastrocnemius, and brachioradialis muscles. With this instrument, percutaneous muscle biopsies were performed noninvasively and simply with procurement of sufficient material (30-40 mg) for satisfactory histological examination.
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Eight healthy male college students were selected and eight noise exposure conditions were planned. The noise exposure time of all the experiments was 14 h. Measurement of the TTS growth at 4 kHz was investigated during these 14 h. Saliva collected every 3 h was also examined for cortisol throughout the 24-h period. The exposure noises used in this experiment were pink noise and pure tone of 3 kHz. The time patterns of trapezoidal noise were as follows. The rise and decay times were 1 s respectively and the peak level was 1 s for the (A I type), being 500 ms and 1.5 s respectively for the (A II type). Three measurements were made: 1. TTS. Under intermittent noise exposure at 80 dB(A), exposure of 20% of the on fraction induced significant TTS growth, but exposure of 13% of the on fraction did not induce TTS growth. Under exposure at 75 dB(A), exposure of 66% of the on fraction did not induce TTS growth. Under pure tone exposure of 3 kHz at 75 dB(A), exposures of 20% and 30% of the on fraction did not induce TTS growth. There was a significant difference between the TTS induced by a steady state of of 73 dB (A) (Leq of Exp. 2) and that of Exp 2. 2. Urinary 17-OHCS Level. During the noise exposure period (14h), there was a statistically significant difference between the urinary 17-OHCS level of the control condition and that of Exp. 3. In addition, there was no statistically significant difference among the urinary 17-OHCS levels of post-noise exposure. 3. Saliva Cortisol. With intermittent "pink noise" of 75 or 80 dB(A) (Exp. 2, 3, and 4), however, temporary elevation of the saliva cortisol level occurred only at the initial stage of exposure, and lasted for only one hour. Moreover, with steady state noise exposure, evanescent elevation occurred at the lower level of 71 dB(A).
Effects of a single exposure to toluene at a concentration of 1000 for 4 h on rats' systolic blood pressure were investigated. 9 rats were used in each group (control and exposed groups). The basic blood pressure of the exposed group was significantly lower than that of the control group. The movement of systolic blood pressure due to impulse noise exposure was significantly smaller in the exposed group than in the control group. Toluene exposure at concentration of 1000 ppm for 4 h produced narcotic and inhibitory actions in the diencephalohypophysial and the adrenal gland system in rats.
Rats were exposed to toluene at a concentration of 1000 ppm, 6 h/day, 6 times weekly, for 4 weeks. Functional disturbance of the circadian rhythm of spontaneous activity was found after repeated exposure to toluene, although single exposure under the same conditions did not influence the rhythm. The disturbance was characterized by a significant increase in distribution of activity in the "Light' (L) period, and a significant relationship was observed between the total number of days of exposure and the activity level in the L period. The toluene concentration in the blood immediately after the exposure was 6.8-7.2 microgram/ml after one and 18 days of exposure, respectively.
Eight healthy students were exposed to intermittent noise to evaluate the effects of traffic noise on man. The experimental noise exposure conditions were as follows: Exp. 1: Control. Exp. 2: Peak level, 80 dB(A); rise-decay time, 1 sec; duration, 3 sec; and duty cycle 8 sec (on fraction 25%). Exp. 3: Peak level, 75 dB (A); rise-decay time, 500 msec; duration, 4.5 sec; and duty cycle, 8 sec (on fraction 50%). In all experiments, the exposure time was 14 hr. Temporary threshold shift (TTS) growth was followed for 14 hr while saliva cortisol levels were measured for a 24-hr period. Although the coefficient of the regression line of TTS growth recorded in Exp. 1 or Exp. 3 was not statistically significant, the value in Exp. 2 was statistically significant. The circadian rhythm pattern of the saliva cortisol level (during a 24-hr period, mean of 8 examinees) was observed in the three experiments. Essentially, the early morning level of saliva cortisol was high, while the daytime level was relatively low.
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