By the procedure of of factor analysis, the interrelationships of parameters relevant to lead exposure were statistically investigated. The parameters were clas-sified to three groups based on the results of these statistical analysis: the first group contained lead mobilized by CaEDTA and lead in blood, which were considered to be related to the body burden of lead; the second group, ALA-D in erythrocyte, δ-ALA in urine, coproporphyrin in urine and lead in urine, which should be the response to the body burden of lead; the third group, hemoglobin in blood. It was supported that there might be specific biological reactions to lead in people free from occupational or accidental exposure to lead, though the extent of the reac-tions was supposed to be much less than that of occupationally-exposed lead workers. The influence of lead to blood hemoglobin level was not found under usual urban environments. The biological significance seemed to be almost similar between lead in blood and lead mobilization test with the intravenous administration of CaEDTA from the view-point of dose-response relationship of lead. The regressions of urinary coproporphyrin and erythrocyte ALA-D activity on lead mobilized by CaEDTA or blood lead were supposed to be nearly linear in people free from occupational lead exposure.
Protective effect of selenite against methylmercury toxicity was observed in ex-perimentally induced acute and subacute methylmercury poisoning of rats. The protection becomes more evident as the acuteness of methylmercury poisoning de-creases in terms of the total methylmercury dosage administered and the number of survival days after the last dosing, and there appears to be present an optimal dose relationship between the two substances. Protective effect of selenium is likewise clear in subacute methylmercury poisoning in regard to growth rate, incidence of neurological signs and mortality. We did not observe any differences in the protec-tion when administration route was changed.
The effect of benzanthrone (an anthraquinone derivative) on blood coagulation in rats has been investigated. Coagulation time, plasma fibrinogen, platelets, pro-thrombin time, bleeding time and serum calcium have been determined in benzan-throne administered animals at 2, 4, 6, 8, 10, 15 and 30 days. Coagulation time was significantly decreased at 2 days of administration and this decrease remained highly significant upto 10 days. The increase in plasma fibrinogen was highly significant from 2 to 6 days. The number of platelets showed an increase at 2 days which be-came highly significant from 4 to 30 days. Bleeding time was significantly reduced at 10 days. Prothrombin time and serum calcium were unaffected.
Carboxymethylcellulose and polyvinylpyridine N-oxide were tested for their ability to inhibit chrysotile induced hemolysis. Carboxymethylcellulose proved to be an antagonist when used for pretreatment of asbestos dust as well as when the chrysotile-erythrocyte interaction was allowed to take place in its presence. Pretreatment of erythrocytes with the polymer, before their exposure to chrysotile did not prevent the hemolytic action of chrysotile. Polyvinylpyridine N-oxide was antihemolytic to a lesser extent and only at higher concentrations.
The change of convulsion threshold in the rat exposed to toluene was studied in an attempt to experimentally confirm the clinical experience that paroxysm-like abnormal EEGs by injection of 50mg Bemegride and the attacks of syncope or con-vulsion occurred in some patients exposed mainly to toluene. Sprague-Dawley strain male rats had been exposed to 2, 000 ppm toluene vapor 8 hr a day for 8 weeks, and convulsion threshold and body weight were observed. he body weight of the exposed group did not increase during the first week of exposure to 2, 000 ppm toluene, but steadily increased afterward. The body weight of the exposed rats was constantly kept a little less than the control during the exposure, with no significant staistical difference. he convulsion threshold was determined by the peritoneal injection of Bemegride. The total sum of Bemegride injected in a rat till the beginning of convulsion was regarded as convulsion threshold. The convulsion threshold of the exposed group steadily became smaller than the control from 1 to 6 weeks after the beginning of exposure and there were significant statistical differences between the two groups, but after 8 weeks the convulsion threshold became larger a little and there was no significant difference. The decrease in the convulsion threshold by Bemegride suggests that some func-tional and/or organic changes should occur in the central nervous system owing to the exposure to toluene vapor.
To obtain basic data on TLV for toluene and early findings of toluene intoxica-tion, some investigations were undertaken for female shoe makers exposed to low concentration of toluene vapor ranging about 60 to 100 ppm. Subjective symptoms of the exposed group were significantly different from those of control group on sensation of general weakness, dysmenorrhoea, itching and dermatitis of hands and feeling uneasy about solvent vapor. In hematological findings, there was no significant difference in both groups except for appearance rate of Mommsen's toxic granules in peripheral neutrophiles. Mean value and standard deviation of hippuric acid concentration in the urine were 3.26±0.82mg/ml in ex-posed group and 0.35±0.24mg/ml in control group, which revised at 1.024 by specific gravity. There were some significant differences between them in neurologic and muscular function tests such as abnormal tendon reflex, grasping power of not-dominant in the whip hand, decrease in tapping tempo, agility of the fingers, and so forth. These findings suggest that TLV of 100 ppm for toluene adopted in Japan As-sociation of Industrial Health should be reconsidered.
Five different cadmium fixation methods of kidney were investigated in view of the leakage of the metal into fixative solutions and into the other materials for electronmicroscopic preparation. On the other hand, they were examined whether the fine structure was preserved well or not for light-and electronmicroscopic radio-autography. The better method was choiced, to add tannic acid to a fixative contain-ing paraformaldehyde and glutaraldehyde buffered with phosphate.
For sampling of hydrogen cyanide (HCN) gas in atmospheric air, a midget im-pinger containing NaOH aq. as absorbing solution was found to be the most suitable apparatus. The efficiency of sampling for HCN was affected by the absorbing con-ditions greatly. In this procedure, NaOH in the solution were consumed by CO2 in atmospheric air gradually1). To absorb HCN thoroughly, it was necessary to keep enough NaOH in the solution. The solution containing CN'-compounds generated HCN gas, if the alkalinity of the solutions was lost. Beside these, various other conditions also had to be considered to absorb CN'-compounds in atmospheric air.
The toxic volatile components in acrylamide and urea formaldehyde resins which were industrially manufactured as soil consolidating agents were analyzed by gas chromatography and gas chromatography-mass spectrometry before and after poly-merization. In acrylamide monomer solution, acrylonitrile was contained up to 0.3mg/ml as an impurity and after gelation of the solution by polymerization with sand, it evaporated to air up to 4440mg/m3 at equilibrium. In the solution of urea formaldehyde condensate prior to the gelation, formaldehyde up to 192mg/ml, formic acid up to 20.6mg/ml, trace amount of associated formaldehyde and another higher molecular compound were contained and after gelation of the resin with sand by further condensation, trace ammonia, formaldehyde up to 14900mg/m3, formic acid up to 96mg/m3 and associated formaldehyde up to 1800mg/m3 evaporated from the gel to air at equilibrium. DTA and TG curves were observed on the gels which revealed the dehydration of the gels at 80-180°C and the thermal decomposition at 500-600°C.