Shogo Shima

Serum lipid peroxide level and blood superoxide dismutase activity in workers with occupational exposure to lead

SummaryWe studied whether lead exposure increased the serum lipid peroxide (LPO) level and inhibited blood superoxide dismutase (SOD) activity in workers with occupational exposure to lead and rats injected with lead. We examined the following subjects: (1) manual workers (712 males) from 18 to 59-years-old in steel production with occupational exposure to lead, (2) office workers (155 males) without exposure to lead, (3) rats subcutaneously injected with lead in concentrations of 10 or 20 mg/kg as lead acetate. The nutritional intakes of manual workers and office workers were approximately equal. Serum LPO and high-density lipoprotein cholesterol (HDL-CL) levels in manual workers (LPO: 4.4 ± 1.9 nmol/ml, HDL-CL: 55.6 ± 14.2 mg/dl) were significantly higher than those in office workers (LPO: 4.0 ± 1.4 nmol/ml, HDL-CL: 53.0 ± 13.9 mg/dl). Serum LPO level in the manual workers increased with an increase of the lead concentration in the blood, while blood SOD activity decreased. Similar phenomena were observed in rats subcutaneously injected with lead acetate. Furthermore, the addition of lead at higher than 20-μM concentrations to non-treated rat liver microsomes increased NADPH-dependent lipid peroxidation, and these lead concentrations inhibited bovine erythrocyte SOD activity in vitro assay system. In conclusion, the present results seem to indicate that the increase of serum LPO level in workers with occupational exposure to lead is due not only to the stimulation of lipid peroxidation, but also to the inhibition of SOD activity by exposure to lead in the manufacturing processes.

Effect of food intake on blood lead concentration in workers occupationally exposed to lead

Results from a cross-sectional study showed the concentration of lead in the blood of male workers, aged 20-55 years, occupationally exposed to lead in a steel factory, to be negatively correlated with the daily nutritional content of dietary fiber, iron and vitamin B1 (thiamine) intake. Furthermore, in experiments with rats injected subcutaneously with lead acetate, lead levels in blood and femur of animals on a vitamin-rich laboratory chow were lower than those fed a general laboratory chow. Moreover, in the group fed the vitamin-rich chow, lead excretion in feces increased, while excretion in urine did not. These results suggest that lead excretion from the body may be increased by a high intake of nutrients such as thiamine, iron and fiber, that lead excretion in feces via bile may be enhanced by a large intake of vitamins such as thiamine and that accordingly the lead concentration in the blood of the workers is reduced.

Behavior of urinary hydroxyproline and cigarette smoking effect in silicosis.

This study was conducted through regular pneumoconiosis examination according to the law on 1, 096 employees of medium and small-sized ceramic enterprises in Tokai district in 1981-82.Interview examination with BMRC questionnaire, X-ray examination and measurement of urinary hydroxyproline to creatinine ratio (HOP ratio) were carried out in order to elucidate the relationship between silicosis and urinary HOP ratio and to demonstrate the effect of smoking on pneumo-fibrosis. Grade of silicosis was classified into five types (0 to 4) based on the Japanese Classification of Radiographs of Pneumoconioses.In evaluating the behavior of urinary HOP ratio, when smoking factor is added in the early grade of pneumofibrosis (type 1 and type 2), collagen decomposition rate is rapidly repressed and fibroplastic conditions develop to the final grade as type 3 and type 4, although smoking itself does not seem to induce pneumofibrosis.To exclude the effects of smoking, nonsmoking group was used for measurement of HOP ratio by grade. The HOP ratio in type 0 was lowest and HOP ratio increased in the order of type 1 and type 2. The turning point was found in type 2 and their HOP ratio decreased one after another.The turning point shifted from type 2 to type 3 in the case of non-smokers without any index symptoms by BMRC questionnaire and also shifted to type 1, in the case of non-smokers with them. Shifting of turning point suggests that index symptoms also promote fibroplastic activities.

Immune Response in Guinea Pigs Injected with Insoluble Beryllium Compounds

Immune Response in Guinea Pigs Injected with Insoluble Beryllium Compounds: Tsutomu Yoshida, et al. Department of Public Health, Fujita Health University School of Medicine—The changes in immune response of guinea pigs intrapleurally injected once with beryllium oxide (BeO) or beryllium copper alloy (Be‐Cu) were examined. To evaluate the changes in immune response of guinea pigs, two indicators, beryllium lymphocyte transformation test (Be‐LTT) and complement hemolytic activity (CH50), were used. The BeO or Be‐Cu injection groups was divided three groups, a high concentration injection group (36 μg Be dose), a low concentration injection group (3.6 jug Be dose) and the control group. The Be‐LTT and CH50 were determined in the blood of guinea pigs at 4, 8 and 16 weeks after Be administration. The Be‐LTT value at the 4th week in the BeO groups (a high or low concentration injection group, respectively) showed a statistically significant increase (p <0.01) compared with that of the control. In the Be‐LTT value for BeO at 8 and 1 6 weeks after Be injection and the Be‐Cu groups, there were no statistical difference between the Be administration groups and the control. On the other hand, only the CH50 of the high concentration group at the 8th week in the BeO injection group was significantly decreased (p <0.01) compared with that of the control. In the other Be injection group, no significant changes in the CH50 was observed compared with the control group. On the basis of the results observed in the present study, there may be a slight difference in the effect on the immune response of guinea pigs caused by BeO or Be‐Cu administration. The immunotoxicity of Be in guinea pigs may manifest itself more intensely in the cellular immune response than in the humoral immune response.