An experimental study was performed to investigate the effects of local vibration on the brain monoamines of rats.
The rats' hind limbs were exposed to vertical sinusoidal vibration at frequencies of 20-960 Hz under constant acceleration of 50 m/s² for 240 min. Rats were decapitated immediately after the exposure, the brains were quickly removed from the cranium and blood was collected in a heparinized beaker. The brain was divided into seven regions on an ice plate, and the changes of norepinephrine (NE), dopamine (DA) and serotonin (5-HT) in the whole brain or regional brains were examined.
Furthermore, to investigate the mechanism of the appearance of peripheral effects induced by local vibration, the response of plasma dopamine-β-hydroxylase (DBH) activity was observed with and without pretreatment by 6-hydroxydopamine (6-OHDA), known as a drug for chemical sympathectomy.
The amines were determined by fluorometry and DBH activity was by radioimmunoassay.
The results obtained were as follows:
1) NE level in the whole brain showed a tendency to decrease compared with the controls at a frequency of 120 Hz and an acceleration of 50 m/s².
2) Levels of DA and 5-HT in the whole brain showed no particular changes at any frequencies used in the present study.
3) In the study of regional brains, NE showed a tendency to decrease at a frequency of 60 Hz and a significant decrease at a frequency of 120 Hz in the hypothalamus. In the hippocampus, NE showed significant decreases at frequencies of 60 Hz, 120 Hz and 240 Hz, especially at 120 Hz. DA showed a tendency to decrease in the striatum at a frequency of 20 Hz and a significant increase at a frequency of 60 Hz in the medulla oblongata and pons. 5-HT showed a significant increase in the hypothalamus at frequencies of 20 Hz and 120 Hz.
4) The changes in brain amines induced by local vibration were compared with those by whole body vibration. By exposure to local vibration at a frequency of 20 Hz and acceleration of 50 m/s², the amines in the whole brain were not meaningfully affected, whereas in whole body vibration at the same frequency and acceleration significant effects were observed. NE level was decreased significantly to 57% of that of the control in whole body vibration (20 Hz, 50 m/s²) and showed a tendency to decrease to 79% of that of the control in local vibration (120 Hz, 50 m/s²). Thus the effect of whole body vibration was much greater than that by local vibration. DA was unaffected by either whole body vibration and local vibration. 5-HT was remarkably elevated by whole body vibration and slightly elevated by local vibration. From the view point of observations of regional brains, NE showed a significant decrease or a tendency to decrease in the hypothalamus and the hippocampus, and the degree of NE depletion was much severer in whole body vibration exposure than in local vibration exposure.
5) Plasma DBH activity was significantly elevated by local vibration compared with the control. On the other hand, when rats pretreated with 6-OHDA were exposed to local vibration, no increase of DBH activity was observed, and the level of DBH activity was almost the same as that of rats treated with 6-OHDA without vibration stress. Thus, from the observation of the response of DBH activity as an indicator, it is estimated that the peripheral effect by local vibration appears through the postganglionic sympathetic nerve fiber.

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A simple analytical method for urinary phenol by high performance liquid chromatography was tested.
This procedure consists of the following three steps: (i) hydrolysis of urine with hydrochloric acid, (ii) extraction of phenols with isopropylether, (iii) separation and determination of phenol by high performance liquid chromatography, under the following operating conditions: column, LiChro-sorb RP 18 (250 mm×4 mm, I. D.); mobile phase, acetonitrile-water (3:7, v/v) with a flow rate of 0.8 ml/min; column temperature, 40°C; detection, UV monitor at 270 nm. The detection limit (signal-to-noise ratio=2) was 1 ng. The analytical results by this method were compared with those obtained by another method used for gas chromatography. The analytical results obtained by the two methods were in good agreement (r=0.998) for 30 normal urine samples tested. The geometrical average value for phenol in normal urine samples (n=30) was 8.2 μg/ml.
Therefore this method was proved to be useful for biological monitoring of benzene exposure.

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Infrared heat radiation was directed onto the backs of healthy female subjects wearing a white or a black dress. Local skin thermal reactions of the back and the thigh were observed with reference to clothing color in a climate chamber where the ambient temperature was set at 20, 25 or 30°C. Heat flow, skin temperature and air temperature under the clothing were measured.
In the absence of radiation, skin temperature was higher than air temperature under clothing on the back and the thigh. Heat radiation caused both skin temperature and air temperature under clothing to rise, but the rise was considerably greater with black clothing than with white.
As the effect of radiation was indirect, heat flow direction at the thigh was the same as in the absence of radiation. The thermal resistance index was calculated from skin temperature, air temperature under clothing and heat flow. Upon radiation exposure, the index of a black-clothed back tended to decrease with rising globe temperature. On the contrary, the index of a white-clothed back increased from a low negative value. This index is useful in assessing the skin-cloth system.

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The effects of 10 mg/kg and 5 mg/kg intraperitoneally administered triethyl lead on rats were observed through measurement of the following: changes in body weight, passive aggressiveness, wheel running activity, the performance level of Rota-Rod Treadmill, and emotional responses in the open field.
The results obtained were as follows:
1. Weight losses of TEL-treated rats were recorded from 2 days after injection to 20 days after injection.
2. Scores of passive aggressiveness were drastically increased following administration of TEL. Maximum passive aggressiveness was observed 4 days after injection and it continued until 13 days after injection.
3. Wheel running activity was decreased for 2 days after injection. It was observed that TEL-treated rats showed extreme reaction on the wheel running activity test for about 30 days after administration.
4. Endurance on the Rota-Rod Treadmill was significantly reduced in the 10 mg/kg group.
5. The amount of defecation, ambulation and rearing of the treated group as measured by covariance analysis did not differ from that of the controls.
6. The whole time course of intoxication and the precise measurement of neurotoxicity due to TEL could be followed using the techniques of behavioral toxicology.

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Pulmonary emphysema was induced in rats by a single intratracheal instillation of swine pancreatic elastase. After adequate development of the pulmonary emphysema, the animals were initially exposed to 1.9 ppm ozone for 3 hrs, and 3 days later, challenge-exposed to 5.1 ppm ozone for 3 hrs and immediately sacrificed to investigate the extent of the development of tolerance to ozone judged by the formation of edema. Although the body weights of the pulmonary emphysematous rats were the same as those of the saline-treated control rats, the lung weights of the former were heavier. The extent of the edema formation by ozone and of the tolerance to ozone of the pulmonary emphysematous rats seemed to be quite similar to those of the saline-treated control rats. On the other hand, although the exposure of the salinetreated control rats to 1.9 ppm ozone for 3 hrs resulted in an increase in lung weight without edema 3 days after the exposure, the pulmonary emphysematous rats did not show such a response.

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