Am. Bernard

Significance of cadmium concentration in blood and in urine in workers exposed to cadmium

Abstract All the workers (n = 11) occupied in a small factory producing cadmium salts were followed up during several months. Four of them were newly employed workers. At regular time intervals the workers were equipped with a personal air sampler and cadmium concentrations in blood and in urine were measured. The total airborne concentration of cadmium at the different work places was very high. The median values ranged from 110 to 2125 μg/m3. In view of the hygiene practice of the workers, ingestion of cadmium may also have played a role in the overall exposure. After the start of the exposure, cadmium concentration in blood increases linearly up to 120 days and then levels off. This suggests that when equilibrium is reached cadmium level in blood is a good indicator of the average intake during recent months. The interpretation of the cadmium levels in urine is more complex. In seven workers exposed for more than 250 days cadmium level in urine seemed to reflect mainly current exposure. Our results suggest also the existence of three phases in the evolution of the Cd levels in urine after the onset of high exposure. A first phase of very short duration (0–15 days) is observed during which cadmium level in urine increases rapidly to reach a value of about 15 μg/g creatinine. This is followed by a second phase (15–120 days) during which cadmium level in urine increases more slowly. After 120 days there is apparently a rapid increase of the cadmium level in urine (third phase). The results obtained during this study as well as our previous clinical observations on workers exposed to cadmium lead us to propose a tentative biological threshold of 10 μg Cd/g urinary creatinine. It should be stressed that this proposal applies only to adult males occupationally exposed to cadmium and not necessarily to other groups of the general population.

Chinese herbs nephropathy-associated slimming regimen induces tumours in the forestomach but no interstitial nephropathy in rats

Abstract Chinese herbs nephropathy (CHN), a rapidly progressive interstitial fibrosis of the kidney, has been described in approximately 100 young Belgian women who had followed a slimming regimen containing some Chinese herbs. In 4 patients multifocal transitional cell carcinomas (TCC) were observed. Aristolochic acid (AA), suspected as the causal factor of CHN, is a well known carcinogen but its ability to induce fibrosis has never been demonstrated. The objective of this study was to evaluate the latter using doses of AA, durations of intoxication and delays of sacrifice known to yield tumours in rats. We also tested the hypothesis that a possible fibrogenic role of AA was enhanced by the other components of the slimming regimen. Male and female rats were treated orally with 10 mg isolated AA/kg per day for 5 days/week, or with approximately 0.15 mg AA/kg per day 5 days/week contained in the herbal powder together with the other components prescribed in the slimming pills for 3 months. The animals were killed respectively 3 and 11 months later. At sacrifice, animals in both groups had developed the expected tumours but not fibrosis of the renal interstitium. Whether the fibrotic response observed in man is due to species and/or strain related differences in the response to AA or to other factors, remains to be determined. Interestingly, despite the addition of fenfluramine and diethylpropion, two drugs incriminated in the development of valvular heart disease, no cardiac abnormalities were observed.

Comparison of sodium dodecyl sulfate-polyacrylamide gel electrophoresis with quantitative methods for the analysis of cadmium-induced proteinuria.

SummaryThe urinary protein patterns of sixteen control workers and twenty-two workers exposed to cadmium were determined by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate. The results were compared with those obtained by the quantitative determination in urine of total protein and specific proteins (β2-microglobulin, albumin, transferrin, and IgG). They confirm that the molecular weights the proteins which are excreted in greater amounts in case of renal damage induced by cadmium range from 10,000 to 160,000. The areas of the electrophoretic peaks with the relative mobility of β2-microglobulin, albumin, transferrin, and IgG are significantly correlated with the results obtained by the immunological determination of these proteins. A correlation was also observed between the total peak area of the electrophoretic patterns and the total urinary protein measured by the biuret method. Electrophoresis in polyacrylamide gel containing sodium dodecyl sulfate appears to be a suitable-semi-quantitative method for the detection of kidney damage induced by cadmium.

Relationship between exposure to heavy metals and prevalence of renal dysfunction.

Total proteinuria (biuret method) and the urinary excretion of specific proteins (albumin, transferrin, orosomucoid and IgG measured by an automated immunoprecipitin reaction and beta 2-microglobulin determined by radioimmunoassay) have been assessed in four groups of workers: a control group (n = 88) and a group exposed to cadmium (n = 148), mercury vapour (n = 63) and lead (n = 25) respectively. The results demonstrate that a moderate exposure to lead (lead concentration in blood < 62 micrograms/100 ml) does not change the prevalence of renal dysfunction, whereas mercury vapour exposure increases the prevalence of subjects with excessive excretion of albumin (> 12 mg/g creatinine), orosomucoid (> 4.35 mg/g creat.) and IgG (> 3.5 mg/g creat.). Besides an increased excretion of beta 2-microglobulin (> 200 micrograms/g creat.) workers exposed to cadmium excrete a greater amount of high molecular weight proteins. An increased excretion of urinary proteins occurs when mercury and cadmium level in urine exceeds 50 and 10 micrograms/g creatinine respectively.

α1-Antitrypsin in cadmium toxicity: An evaluation of its suggested role

Chowdhury and Louria [1] reported that cadmium could reduce in vitro the concentration and the trypsin inhibitory capacity of plasma alpha 1-antitrypsin. They suggested that this could explain the emphysema observed in some workers exposed to cadmium. Using the same experimental approach as these authors, we could not reproduce their observations. Furthermore, in vivo results obtained on workers excessively exposed to cadmium during more than 20 years and exhibiting obvious signs of chronic cadmium intoxication did not reveal a decrease in the concentration and the activity of plasma alpha 1-antitrypsin.

Epidemiologic Approach for the Assessment of Acceptable Exposure Levels to Cadmium and Manganese

This paper deals with the problem of health risk assessment of long term exposure to chemicals with special emphasis on two inorganic pollutants : cadmium and manganese and illustrates the use of biological markers for assessing the no-effect levels of these pollutants.