Biological indicators of cadmium exposure and toxicity

The increasing environmental and occupational exposure of populations to cadmium creates the need for biological indicators of cadmium exposure and toxicity. The advantages and disadvantages of monitoring blood cadmium, urinary, fecal, hair, and tissue cadmium, serum creatinine, beta 2-microglobulin, alpha 1-antitrypsin and other proteins, and urinary amino acids, enzymes, total proteins, glucose, beta 2-microglobulin, retinol-binding protein, lysozyme, and metallothionein are discussed. It is concluded that urinary cadmium, metallothionein and beta 2-microglobulin may be used together to assess cadmium exposure and toxicity.     

Inhibition of cadmium teratogenesis by a mercaptoacrylic acid (MFA)

The teratogenic effect of cadmium can be diminished by a number of mechanisms including zinc and pretreatment with cadmium and mercury. In this study, the oral administration of alpha-mercapto-beta-(2-furyl)-acrylic acid (MFA) protects against cadmium-induced malformations and embryonic death. This protection is probably mediated by the chelation of the cadmium ion rather than metallothionein (MT) synthesis.     

Biological indicators of cadmium exposure and toxicity

Summary The increasing environmental and occupational exposure of populations to cadmium creates the need for biological indicators of cadmium exposure and toxicity. The advantages and disadvantages of monitoring blood cadmium, urinary, fecal, hair, and tissue cadmium, serum creatinine, ₂-microglobulin, ₁-antitrypsin and other proteins, and urinary amino acids, enzymes, total proteins, glucose ₂-microglobulin, retinol-binding protein, lysozyme, and metallothionein are discussed. It is concluded that urinary cadmium, metallothionein and ₂-microglobulin may be used together to assess cadmium, exposure and toxicity.     

Metallothionein induced in the earthworm

Summary One of the 3 different molecular weight cadmium-binding proteins induced in the earthworm was characterized as a metallothionein; this characterization was based on a high cysteine and cadmium content, low molecular weight, heatstability, and mercaptide bonding.M.Y. and K.T.S. thank Dr K. Kubota for encouragement.To whom correspondence should be addressed.     

Metallothionein induced in the frogXenopus laevis

Summary A low molecular weight cadmium- and copper-binding protein, induced in the liver of the frog,Xenopus laevis, by the administration of cadmium, was shown to consist of a single isoprotein and was characterized as an amphibian metallothionein based on its high cysteine and metal content, its low molecular weight, and the lack of aromatic amino acids.The authors thank Dr K. Kubota for his encouragement.     

Mineralocorticoid treatment and the adrenalectomy-induced increase in monoamine oxidase activity

Summary Bilateral adrenalectomy in the rat results in an increase in heart monoamine oxidase activity in animals drinking water and in animals drinking 0.9% saline. Daily administration of deoxycorticosterone acetate prevented the increased monoamine oxidase activity in the animals drinking saline but not in those drinking water.Acknowledgment. This work was supported in part by a grant from the American Heart Association — Louisiana, Inc.     

Chronic hydrogen peroxide intake and peroxide metabolizing enzyme activities in some tissues of mice and rats

Chronic daily intake of 0.5% H2O2 in drinking water decreased Se-dependent glutathione peroxidase (Se-GSHPx) activity in rat skeletal muscle, kidney and liver. Non-Se GSHPx activity decreased in kidney. Deprivation of drinking water decreased Se-GSHPx activity in kidney and non-Se GSHPx activity in kidney and liver. H2O2 intake decreased activity of catalase in rat skeletal muscle. H2O2 intake or water deprivation caused no changes in these enzyme activities in mice.     

Similarities between metallothionein and low molecular weight testicular cadmium-binding protein

The incorporation of 35S-cysteine and 3H-glutamic acid was studied in mouse hepatic and renal metallothionein and in testicular cadmium-binding protein of similar molecular weight. Preferential incorporation of 35S-cysteine over 3H-glutamic acid was observed not only in hepatic and renal metallothionein, but also in testicular cadmium-binding protein. When the antigenic reactivity of these proteins was compared, all three proteins reacted with the metallothionein antibody. These similarities suggest that the low molecular weight testicular cadmium-binding protein is apparently metallothionein.     

黄腊溪饮用水源地非点源污染及水环境容量初探

以四川省大英县隆盛镇黄腊溪饮用水源地为研究对象,根据当地丰水期的实际情况和实测数据建立了一维水质模型。测试结果表明,8月CODcr、TN和9月TN已超过地表水Ⅲ类水质目标。结合水环境容量计算公式得知：8月上中旬污染物中CODcr和TN各需要削减408．25t·a^-1和2．52t·a^-1的入河量,而9月则应削减110．92t·a^-1的TN入河量才能满足当地饮用水水源地标准。最后针对污染源的排放情况提出相应的水环境防治对策和建议。     

Similarities between metallothionein and low molecular weight testicular cadmium-binding protein

Summary The incorporation of³⁵S-cysteine and³H-glutamic acid was studied in mouse hepatic and renal metallothionein and in testicular cadmium-binding protein of similar molecular weight. Preferential incorporation of³⁵S-cysteine over³H-glutamic acid was observed not only in hepatic and renal metallothionein, but also in testicular cadmium-binding protein. When the antigenic reactivity of these proteins was compared, all three proteins reacted with the metallothionein antibody. These similarities suggest that the low molecular weight testicular cadmium-binding protein is apparently metallothionein.     

饮用水源水质评价的模糊聚类模型的研究

考虑到饮用水源样本并没有严格的属性,以及它们在形态和类属方面存在看中介性,确定了对人类生理健康影响较大的高锰酸盐指数、生化需氧量、总氮、氨氮、氟化物、总磷、溶解氧等9项评价因子;将特征空间中一组没有类别标记的矢量按某种相似性准则划分到若干个子集中,实现每个子集代表整个样本集的某个或者某些特征和性质;建立起基于模糊聚类法的饮用水源水质评价模型。最后,将所建模型应用到阜新市目前饮用水源地水质评价中,应用效果表明：所建模型既能有效地判断饮用水源水质类别,又能确定水体中主要污染物和主要污染源,通过不同评价方法结果的比较分析,体现了所建模型的良好有效性和适用性。     

Lead metabolism in lactation.

A 2-fold increase in lead absorption was observed in lactating animals which received 2 mg Pb/l in drinking water. About one-half of the absorbed lead was transferred to the litters.     

Nutritional requirements of aeromonads and their multiplication in drinking water

Aeromonads can utilize a wide range of low molecular-weight compounds, including amino acids, carbohydrates and long-chain fatty acids at a concentration of a few micrograms per liter. Utilization of biopolymers such as gelatin, casein and amylose is slow at this concentration level. The concentration of substrates available for an A. hydrophila strain in drinking water was usually below 10 micrograms of C/l. The autochthonous bacteria utilized these substrates more rapidly than the aeromonads. The multiplication of aeromonads in drinking water during distribution is therefore explained by their growth on biomass components in the biofilm and in sediments in the pipes.     

Chronic hydrogen peroxide intake and peroxide metabolizing enzyme activities in some tissues of mice and rats

Summary Chronic daily intake of 0.5% H₂O₂ in drinking water decreased Se-dependent glutathione peroxidase (Se-GSHPx) activity in rat skeletal muscle, kidney and liver. Non-Se GSHPx activity decreased in kidney. Deprivation of drinking water decreased Se-GSHPx activity in kidney and non-Se GSHPx activity in kidney and liver. H₂O₂ intake decreased activity of catalase in rat skeletal muscle. H₂O₂ intake or water deprivation caused no changes in these enzyme activities in mice.     

Experimental liver fibrosis induced in rats receiving high doses of alcohol and alternating between regular and vitamin-depleted diets

Liver fibrosis was induced in rats by simulating human alcoholic eating and drinking patterns. Alcohol addiction was established by gradually increasing the ethanol concentration in the drinking water; salts were added at the terminal stage. The hepatocytes of rats receiving alcohol concentrations exceeding 50% (v/v) (similar to vodka) exhibited alcoholic hyaline (Mallory bodies). Alcoholic liver fibrosis was induced by alternating between regular and autoclaved (vitamin-depleted) diets, simulating the irregular eating habits of human alcoholics. In the livers of rats receiving 70% (v/v) ethanol (comparable to absinthe) with 25% saline and fed the alternating diets, pericellular fibrosis was induced. No significant difference in calorie intake between control and alcohol rats was detected except when rats underwent drinking bouts (heavy drinking phase). This indicates that neither a high-fat diet nor a choline-depleted diet is necessary to induce the alcoholic fibrosis seen in human alcoholics.     

Liver vitamin A stores in chronic alcoholism in rats: effect of propylthiouracil treatment

Administration of alcohol to rats through drinking water for 8 weeks produced a significant decrease in the liver vitamin A stores without causing any change in the plasma vitamin A levels. Treatment of the alcoholic rats with propylthiouracil for 2 weeks restored the liver vitamin A reserves to control levels.     

Liver vitamin A stores in chronic alcoholism in rats: Effect of propylthiouracil treatment

Summary Administration of alcohol to rats through drinking water for 8 weeks produced a significant decrease in the liver vitamin A stores without causing any change in the plasma vitamin A levels. Treatment of the alcoholic rats with propylthiouracil for 2 weeks restored the liver vitamin A reserves to control levels.     

Oral melatonin produces arrhythmia in sparrows

Summary House sparrows,Passer domesticus, exhibit circadian rhythms of perch-hopping behavior. The rhythm was abolished by ad libitum administration of melatonin in the drinking water.Support was provided to S. Binkley by NSF PCM 8314331.     

The influence of ingested fluoride on the ascorbic acid concentration in guinea-pig tissues

Summary Fluoride added to drinking water at concentrations of 50 and 70 ppm provided highly significant increases in the ascorbic acid concentration in tissues but was without effect on the serum alkaline phosphatase and cholesterol.JEWD was supported by a Beecham Products grant.     

Toxic effect of cadmium nitrate on the liver of Channa punctatus.

Exposure of a fresh water fish, Channa punctatus, in a medium containing as low as 0.01 ppm of cadmium nitrate, resulted in the necrosis of hepatic cells. A temporary recovery of these cells was however observed when the animals were exposed to lower concentrations.