Urinary excretion of cadmium, protein, beta-2-microglobulin and glucose in individuals living in a cadmium-polluted area

Cadmium in the environment of three Russian cities and in human hair and urine

Daily cadmium intake was assessed in three Russian cities as were deviations in health of the working population and children who resided near the sources of contamination. In the surveyed workers of a storage battery factory (n = 27), the urinary cadmium content exceeded the threshold of 14 micrograms/l and averaged 53.8 micrograms/l; the average hair cadmium was 99.3 micrograms/g. Workers employed in metallurgic cadmium production (n = 16) had an average urinary cadmium level of 40.9 micrograms/l and a hair cadmium level of 92.0 micrograms/g. Workers in a cadmium-containing dyes plant had an average urinary cadmium level of 9.04 micrograms/l and a hair cadmium level of 25.1 micrograms/g. Increased urinary excretion of beta-2-microglobulin was found only in workers aged 31 y or older. The general population that resided in the vicinity of the cadmium emissions showed increased urine and hair cadmium levels; levels were greatest near the metallurgic plant and the storage battery factory. Air cadmium content and beta-2-microglobulin excretion were correlated (r = 0.96). The findings confirm results of other epidemiologic studies and underscore the necessity of reducing the maximum allowable concentration of cadmium in the atmospheric air because of excessive intake from other sources.

Renal kallikrein excretion as a distal nephrotoxicity marker during cadmium exposure in rats

Cadmium exposure is known to induce hypertension, but development of hypertension is not universal in exposed animals. However, the cellular uptake of cadmium could also exert renal cytotoxic effects which have been, until now, essentially only studied at the proximal tubule level. Kallikrein is an enzyme synthetized in renal cortex and excreted in the urine in the distal tubule. Therefore, to evaluate the distal renal effect of cadmium, we studied the daily urinary kallikrein excretion (UKE) in conscious unrestrained female Brown Norway rats during long-term chronic exposure to 2 dosages of cadmium given subcutaneously 3 times a week, a low dose (LD): 0.25 mg/kg and a high dose (HD): 1 mg/kg. Neither dose of cadmium was able to induce significant hypertension in the treated animals. HD administration for 24 weeks resulted in a decreased UKE associated with an increase in plasma renin activity and sodium and potassium excretions. LD administration had no significant effect on UKE. Twenty weeks after stopping cadmium administration, a persistent reduction in UKE was still observed; furthermore, the group which had been previously administered a LD of cadmium, now also exhibited a reduced UKE. During this re-examination period in both groups, the UKE reductions were associated with normal systolic blood pressure, glycosuria, natriuresis. Our data show that cadmium administration can influence UKE, plasma renin activity, plasma aldosterone concentration and electrolyte excretion without inducing any variation of blood pressure. This may reflect a nephrotoxic, non-hypertensive effect. Since this effect persisted after stopping cadmium administration, it may indicate a prolonged irreversible nephrotoxic effect at the distal nephron level. Thus, UKE may be a useful non-invasive index to evaluate distal nephrotoxicity.

Cadmium levels in the urine of female farmers in nonpolluted areas in Japan

About 1200 urine samples were collected, mostly in winter seasons in 1982-1984, from adult women in 7 nonpolluted areas in widely separated parts of Japan, and analyses for cadmium (Cd-U) were conducted in a single laboratory. The geometric mean (GM) by decades of age groups of Cd-U, after adjustment for a specific gravity of urine of 1.016, increased from 0.88 microgram/l in the twenties to reach a maximum of 1.78 micrograms/l in the fifties followed by gradual decrease to 1.31 micrograms/l in the eighties. The effect of smoking (about 8 cigarettes/d as a mean) was absent. Analyses of additional 125 urine samples from men revealed that Cd-U in men was not higher than that in women. When classified geographically, Cd-U was higher in the area on the coast of the Sea of Japan, as suspected in preceding studies on blood cadmium levels and dietary cadmium intakes. The Cd-U levels observed in the present study are similar to the values in previous publications on the Japanese and are apparently higher than the counterpart values from Europe, the United States, and New Zealand.

Effects of cadmium on preimplantation mouse embryos in vitro with special reference to their implantation capacity and subsequent development

A short exposure to 5 or 10 micrograms/ml cadmium chloride for 24 hours disturbed the in vitro development of four-cell and morula-stage embryos of F1 (C57 female X A2G male) mice. Morulae appeared to be less sensitive to cadmium than four-cell embryos. However, the in vitro development of four-cell embryos through compaction to morulae was not affected, though most treated embryos degenerated and decompacted later. It was proposed that cadmium toxicity may not be acting through contact effects on the cell surface and cytoskeleton. It probably interferes with the general energy metabolism of the cells. Although 1 microgram/ml cadmium did not disturb the subsequent in vitro development beyond the implantation stage, a reduced capacity of implantation in vivo was observed after surgical transfer to recipients. In spite of the effects of cadmium salts on the maternal side, the present results suggest that a direct embryotoxic and teratogenic activity of cadmium cannot be excluded.

Medical aspects of environmental pollution. Environmental incidents in the Netherlands 1980-1984

In the Netherlands since 1980, 16 situations have been identified in which man might be exposed to environmental pollutants. This paper provides an overview of these incidents and describes how health risk assessments, public studies and provision of individual medical toxicological care are dealt with. The importance of involving general practitioners and other primary health care personnel at an early stage is stressed.

Histochemical changes in protein disulphide bonds in rat liver and kidney after chronic cadmium administration, and the possible relation to metallothionein

After chronic exposure to low doses of CdCl2 an increase in disulphide bonds has been established in rat liver using a specific staining method for disulphide bonds and cytophotometric quantitation. This increase is dependent on doses and length of exposure time. Evidence is presented that this increase might be related to the accumulation of metallothionein or some other cadmium binding protein. Using the same staining method after long exposure to low doses of CdCl2 a large number of large dark blue stained granules were observed in the proximal tubule cells, with blue stained deposits in the lumen of the proximal and some renal medulla tubules of the kidney. Evidence is presented that this staining pattern corresponds to the destruction of the proximal tubule cell by the cadmium thionein complex.