[Contents of cadmium and zinc in organs of Itai-itai disease patients and residents of Hokuriku District]

Cadmium, zinc and copper relationships in kidney and liver of humans exposed to environmental cadmium

Cadmium, copper and zinc have been determined in kidney cortex, kidney medulla and liver from 51 cadmium-polluted and 122 nonpolluted autopsied subjects. Liver cadmium and zinc were significantly higher in the cadmium-polluted subjects than in the nonpolluted subjects. Kidney cadmium, copper and zinc were lower in the cadmium-polluted subjects because of renal damage. Significant correlations of the three metals were found in the kidney. In the liver the correlation coefficients were significant only between cadmium and zinc.

Heavy metals in human and animal bones from ancient and contemporary France

The concentrations of Cd, Pb, Zn, Ba, Mg and Ca have been determined in 180 human bones from the last five millenia, and in 22 contemporary and 20000-50000-year-old animal bones. The original concentrations of Cd and Zn in the ancient human bones were not changed by fossilization processes, whereas Pb and Mg tended to migrate out of the bones, and Ba and Ca concentrations increased with the age of the bones. The distribution of metals in the structure of both the ancient and contemporary bones is not uniform, and neglecting this may render it difficult to compare results obtained from different studies. In Europe and Peru in the late Middle Ages the concentration of Pb in human bones increased by one order of magnitude. The high level of Pb persisted in Europe for several centuries and only recently decreased by an order of magnitude. The concentration of Cd has increased in human bones in the 20th century, to about ten times above the pre-industrial level. The concentration of Pb in contemporary cow bones from France is below analytical detection limits, probably due to competition of Pb with Ca and P which are added to cow fodder as mineral additives.

Variation of cadmium accumulation among Japanese

Human liver, renal cortex, and heart muscle from 394 autopsied Japanese who had lived in eight districts of Japan were sampled. Subjects included 200 males between 0 to 89 yr of age and 194 females between 0 to 94 yr of age. Cadmium, copper, and zinc in both liver and renal cortex, as well as cadmium in heart muscle were compared by district, sex, age, and smoking habits. Statistical results revealed that the difference of each heavy metal distribution by eight districts is significant and that cadmium and zinc levels in liver and renal cortex sampled from north-central Japan were the highest. This probably results from the larger intake of dietary cadmium and zinc via rice since this area is known as one of the better rice growing regions in Japan. Although there is a lack of precise information on smoking habit, cadmium in liver and zinc in liver and renal cortex of males smoking eight or more cigarettes per day were statistically higher than that of nonsmokers and those who smoked less than seven cigarettes per day. However, cadmium in renal cortex was not significant between the two smoking groups. Further studies should be performed to determine the health significance of an increased intake of cadmium by populations from the viewpoint of global biogeochemistry.

Differential susceptibility of L cells in the exponential and stationary phases to cadmium chloride

Comparative studies of the cellular toxicity and uptake of cadmium in L cells in the exponential and stationary phases were done. The LD50 of cadmium chloride to L cells in the exponential and stationary phases was 5.5 and 30.5 muM respectively and the cadmium content of L cells exposed to 5.4 muM cadmium chloride for 3.5 hr in the exponential and stationary phases was 0.123 and 0.065 mug/10(6) cells, respectively. These results suggest that the higher susceptibility of cells in the exponential phase to cadmium may be caused by an increased permeability of the cell membrane to cadmium.