The erythrocyte, plasma and brain cholinesterase (ChE) activities of male rats and mice were determined using a simple colorimetric micromethod. In the normal male mice, the plasma ChE activity was 2.3 times higher than that of the erythrocyte. On the contrary, in the normal male rats, the erythrocyte ChE activity was 2.3 times higher than that of the plasma. The brain ChE activity was similar between rats and mice. The erythrocyte, plasma and brain ChE activities were decreased in both rats and mice exposed to diazinon and, however, this enzyme inhibition was most remarkable in the plasma of mice.
Guinea pigs were exposed to exhaust pollutant sulfur dioxide (10 ppm) one hour daily for 30 days and the effect was studied on the lipid profiles of the liver, heart, lung and kidney. The liver exhibited depletion of phospholipids, cholesterol and C/P ratio, but ganglioside contents diminished. Elevated levels of cholesterol, C/P ratio, total lipids and phospholipids were discernible in the heart, and interestingly ganglioside concentration decreased. On the other hand, the lung showed increased concentration of cholesterol, total lipids, C/P ratio, and gangliosides, however, phospholipid values decreased. Moreover, in the kidney, contents of all the lipid investigated were diminished. The rate of malonaldialde-hyde formation enhanced significantly in the lung and the heart. However, the liver and kidney exhibited decreased lipid peroxidation. Results revealed SO2-intoxication enhanced lipid peroxidation in the heart and the lung by modification of lipids, however, in the liver and the kidney endogeneous lipid peroxidation was diminished. Other lipid fractions exhibited correlative findings.
The effect of trivalent and hexavalent chromium compounds on the activities of selective hepatic drug metabolising enzymes and renal enzymes, in relation to the duration of exposure and tissue concentration of the metal in rats, was investigated to evaluate their potential toxicity. The activity of hepatic aniline hydroxylase decreased more markedly than that of amino N-demethylase on treat-ment with Cr irrespective of valence state. The activity of hepatic glutathione S-transferase decreased with duration of treatment with Cr+6, more significantly than with Cr+3. On the other hand, the levels of renal glutamic oxalacetic trans-aminase, acid phosphatase and lactic dehydrogenase were lowered significantly on treatment with Cr+3 only. The liver and blood concentrations of Cr increased with duration of exposure, more markedly in animals exposed to Cr+6. The uptake of renal Cr was however very slow and was independant of valence state of the metal.
Corporeal distribution and placental transfer of selenium after a single injection of sodium selenite (SS) were investigated over a period of 24 h with regard to the gestational stages of mice and the injection routes of SS. On day 16 of gestation, feto-placental accumulation of selenium was remarkably increased compared with that on day 12 following subcutaneous (sc) injection of SS. Selenium concentrations in the maternal liver, kidneys and lungs were higher on day 16 than on day 12. These results explain the occurrence of the enhanced abortion or maternal death due to SS injection (sc) on day 16 compared with that on day 12, in the previous study. Intravenous (iv) injection of SS caused increased selenium concentrations in most of the maternal organs and tissues but not in the placenta or the fetus compared with sc injection. This may explain the disap-pearance of the abortion-inducing effect of SS when iv injection is used.
Titan dust containing about 50% Ti, and titanium hydride (TiH2) con-taining 99.97% Ti were inhaled by rats and rabbits. TiH2 dust was infused intra-tracheally in rats, and the effects of titan dust on the laboratory animals were tested. Rats and rabbits were exposed to titan dust at concentrations of 22.4, 70.5, and 476 mg/m3 for periods ranging from 1 month to about one year, and those surviving were observed for about one year. In the case of TiH2 dust, rats and rabbits were exposed to a concentration of around 529 mg/m3 for priods of 2 to 8 months, the TiH2 dust being infused intratracheally in the case of rats. Radio-logically in rabbits, obvious nodular shadows were revealed in the chests of rabbits exposed to titan dust, and such findings increased chronologically. Histopatho-logically, retention of the fine dust in alveoli and lymph nodes, proliferation of the alveolar walls, hyperplasia of connective tissue cells, and phagocytes and macrophages containing absorbed dust particles were found together with fibrosis. Suspensions of the TiH2 dust in physiological saline solution containing 10, 50, 100, and 500 mg in 1 ml respectively, were infused intratracheally in 39 male rats. In this intratracheal infusion group and the TiH2 inhalation group changes in bron-chioli, lung and lymph nodes, dust cells and giant cells, bronchopneumonia and granulomatous pneumonia, and intraalveolar fibrosis were shown. As a result of these investigation, it was concluded that the inhalation of titan dust or titan compounds such as TiH2 can produce respiratory disorders and pulmonary fibrosis (titanosis) in laboratory animals.
It is thought that bilateral pleural plaque is a specific sign indicating evidence of asbestos exposure. Using miniature films taken in mass radiography examination for inhabitants aged 50-69 years, a comparative study on prevalence of pleural plaque in Japan & Sweden was carried out. The films were read by a Japanese group, after an exchange-reading program of standard films for pleural plaque. The prevalence was the highest in T city of Japan where a shipbuilding is the principle industry; 10.8% for males and 1.1% for females. Furthermore, Y city of Japan where ship building industry is located showed higher prevalence of pleural plaque compared with the rural district of Japan; 7.7% for males and 0.5% for females in the former, 1.6% for males and 0.1% for females in the latter. It was 6.2% for males and 0.6% for females in U country of Sweden. According to analysis of occupation in the U country, we found higher pre-valence of pleural plaque in the occupational group suspected of more exposure to asbestos.
The effects of mica dust injected intratracheally and parenteral admini-stration of choline were studied in the lungs of albino rats. The intraperitoneal administration of choline (25 mg, 5 days/week) for 10 weeks caused dilation of lymphatic vessels along with adenomatoid changes in the lungs at 330 days. Mica alone (25 mg, intratracheal) provoked pulmonary fibrotic lesions with dilation of lymphatic vessels at 330 days. However, the combined action of mica dust and choline produced adenocarcinoma of bronchiolar epithelium at the termination of the experiment (339 days). Choline as an integral part of, cell membrane, its possible role in enhancing the reaction in the lungs exposed to mica dust is discussed.
To clarify the conditions and the mechanism of contact dermatitis from organophosphorus insecticides, case analysis of 202 patients with contact dermatitis from organophosphorus insecticides, who were collected from all over the country in cooperation with the members of the Japanese Association of Rural Medicine, and some related experiments were undertaken. The results were as follows: 1. From the case analysis, the solitary compounds of organophosphorus insecticides chiefly attributed to the dermatitis were DDVP, salithion, sumithion, phosvel, cyanox, kilval, diazinon and malathion in order. 2. The regions of the dermatitis were finger (62.4%), face (39.6%), forearm (31.7%), neck and nape (29.7%) and so forth. 3. About one quarters (25.2%) of the cases with the dermatitis had complicationwith symptoms of acute poisoning from organophosphorus compounds. The rates ofpatients ragarding the prognosis of the dermatitis were relatively high in healed cases (44.1%) and in treatment cases (27.2%), but about one fourth of the patients (23.8%) were left in incomplete healing. 4. From the animal experiment, relatively strong degree of primary irritating reactions on the skin of guinea pigs were observed especially in such insecticides as DDVP. 5. Potency of allergenicity predicted by the guinea pig maximization test was relatively high (grade III to V) for such organophosphorus compounds as diazinon, fenitrothion and supracide. Apparent cross reactions were observed between supracide and DDVP or dibrom, but they were lower in such cases between organophosphorus insecticides and other pesticide series as benzimidazole and carbamates.