Cadmium and atherosclerosis in the rabbit: reduced atherogenesis by superseding of iron?

This study evaluated the effect of dietary cadmium (Cd) on atherosclerosis in the rabbit. Cholesterol was added to the diet to initiate and/or accelerate atherogenesis. Cd was added to the diet at two dose levels. Uptake of Cd was 55 micro gram/kg body weight (BW)/day at the low dose level and 1350 micrograms/ kg BW/day at the high dose level. Five groups of rabbits were fed five different diets for 9 months: (1) basal diet without additional constituents; (2) background diet, which was basal diet to which cholesterol had been added; (3) the low-dose level Cd diet, which was background diet to which 2 mg Cd/kg had been added; (4) high-dose level Cd diet, which was background diet to which 50 mg Cd/kg had been added; and (5) basal diet to which 50 mg Cd/kg had been added. Dietary cholesterol increased blood total leucocyte count, serum and liver total cholesterol concentrations, serum total bilirubin concentration, low-density lipoprotein vitamin E concentration and induction of atherosclerotic plaques in the aorta and coronary arteries. Cd in the diet increased liver and kidney Cd concentrations in a dose-dependent way, decreased prothrombin time and temporarily increased urea and creatinine clearances. Slight kidney damage was induced by Cd only in animals fed the high-dose level Cd diet (with or without cholesterol). Dietary Cd partly counteracted the dietary cholesterol-induced increases of serum and liver total cholesterol concentrations, and tended to reduce plaque formation in the aorta. Dietary Cd in rabbits fed cholesterol-containing diets influenced cholesterol metabolism and tended to decrease atherosclerosis in a dose-related fashion. This is in contrast with limited epidemiological human data. Dietary Cd also decreased serum ferritin concentration and increased serum transferrin concentration. Free iron concentration is associated with myocardial infarction in man and augments the development of atherosclerosis in rabbits. It is concluded that the observed reduction in atherogenesis is related to dietary Cd-induced changes in cholesterol metabolism, increased rheology of blood and/or, most likely, reduced free iron concentration.

Some elements in domestic and imported fresh fruits marketed in The Netherlands.

Sodium, potassium, arsenic, selenium and tin have been determined in 38 different types of domestic and imported fresh fruits. All samples (n = 242) were analysed for Na und K whereas a limited number of samples (n = 85) of each fruit type was selected for the determination of As, Se and Sn. The median contents, in mass fractions of the edible portion, found for fresh fruits are: Na less than 0.001%; K 0.17%; As 4 micrograms/kg; Se 2 micrograms/kg and Sn less than 0.05 mg/kg. The corresponding 90th percentile values are: Na 0.002%, K 0.34%; As 12 micrograms/kg; Se 10 micrograms/kg and Sn 0.10 mg/kg. Results for selenium reported here differ substantially from those given for a number of fresh fruits in the German Food Composition Tables 1986/1987. The average consumption of 129 g fresh fruit by Dutch citizens in the age category of 22-75 years contributes, in general, marginally to the total daily dietary intake of sodium, arsenic, selenium and tin. Fresh fruit can contribute substantially, up to 23%, to the average oral daily intake of potassium.

Chronic toxicity and carcinogenicity of bis(tri-n-butyltin)oxide (TBTO) in the rat.

In a 106-wk toxicity and carcinogenicity study, groups of 60 male and 60 female weanling Wistar rats were fed 0, 0.5, or 50 mg bis(tri-n-butyltin)oxide (TBTO)/kg diet. In males, feed consumption was increased in all treated groups and increased water consumption occurred at 5 and 50 mg/kg. During the second year, body weight decreased in the 50-mg/kg males, while the females in that group showed no weight gain. Excess mortality was confined to the 50-mg/kg group towards the end of the study. Haematological changes, comprising anaemia, lymphocytopenia and thrombocytosis were noted mainly at the high-dose level. Also, signs of decreased kidney function and increased plasma enzyme activities (alanine aminotransferase, aspartate aminotransferase and alkaline phosphatase) were noted. No effects on serum hormone concentrations (thyrotropin, follicle stimulating hormone, luteinizing hormone or insulin) were observed, except for a decrease in the free thyroxin:thyroxin ratio in both sexes at the high-dose level. Higher serum IgM and IgA levels were present at 50 mg/kg, while, in females, IgG was decreased. At 50 mg/kg, the ovaries, adrenals, spleen (females), heart (males), pituitary, liver and kidneys were increased in weight, but the thyroid weight was decreased in females. The total tin concentrations in liver and kidneys showed a dose relationship and, in general, the concentrations were similar after 1 and 2 yr. Non-neoplastic histological alterations after 1 yr consisted of a decrease in the cell height of the thyroid follicles in all dose groups, with a reduced number of psammoma bodies at 50 mg/kg, a decrease in splenic iron content at 5 (females only) and 50 mg/kg, and a slight bile-duct activation. After 2 yr, only the thyroid changes were still present. In addition, at 2 yr, vacuolation and pigmentation of the proximal tubular epithelium and nephrosis were enhanced at 50 mg/kg. The incidence of benign tumours of the pituitary was significantly elevated and enhanced at 0.5 and 50 mg/kg. At 50 mg/kg increases in pheochromocytomas in the adrenal medulla and in parathyroid adenomas (males) were noted, while adrenal cortical tumours were decreased (males). There was a low, non-dose-related incidence of pancreatic carcinoma. Other tumour rates were in line with control data. It is concluded that lifetime feeding of 50 mg TBTO/kg diet induces toxicity in various organ systems. An increase in some common tumours was found at the high dose, probably due to hormonal or immunological changes.(ABSTRACT TRUNCATED AT 400 WORDS)

Collaborative test of the fluorimetric determination of selenium in a test solution, milk powder and bovine liver.

Results are reported for an inter-laboratory test conducted to assess precision (repeatability, reproducibility) and accuracy of a collaborative method for the fluorimetric determination of selenium (Se). The seven participating laboratories analysed one test solution, four samples of milk powder and two samples of freeze-dried bovine liver. Each set of samples comprised three duplicates: two colorant-disguised milk powders and one code disguised freeze-dried bovine liver. Two of the milk powders were enriched with 90.7 micrograms/kg Se as seleno-DL-methionine. One set of results had to be rejected because the laboratory involved did not adhere to the collaborative method. Results from a second laboratory contained both stragglers and outliers. The five remaining laboratories performed the method satisfactory. Results from these laboratories were statistically evaluated according to ISO 5725. The average coefficient of variation within a laboratory (repeatability) was 4.8% and between laboratories (reproducibility) 6.0% for the milk powder and bovine liver samples. Recovery for the test solution, target value 120 micrograms Se/1, was 96% and the average recovery for the Se enriched milk powder was 88%. The mean result for the milk powder was 98.9 micrograms/kg (n = 10), coefficient of variation (CV) 6.7%, and for Se enriched milk powder 178.3 micrograms/kg, coefficient of variation (CV) 3.6%. For freeze-dried bovine liver, these results were 238.4 micrograms/kg and 4.1% respectively.

[Arsenic, cadmium, mercury, lead and selenium in slaughtered animals: an overview of a 10-year study]. / Arseen, cadmium, kwik, lood en seleen in slachtdieren: een overzicht van 10 jaar onderzoek.

A large number of organs of slaughtered animals were examined for heavy metals, arsenic and selenium during the period from 1970 to 1980. In the present paper, the arsenic, cadmium, mercury, lead and selenium levels determined in porcine and bovine kidneys and livers as well as in porcine brain are reviewed. The following median levels (in mg/kg of fresh product) of the various elements were determined: (table; see text) In a number of cases, organs and meat from the same animal were studied; the levels in meat were much lower than those in organs in every case. A constant ratio between the levels of the elements in meat and those in organs was not observed.

Simple fluorimetric determination of selenium in food and biological materials. A validation study.

A method for the determination of selenium in food and biological materials has been developed. The method involves sample decomposition in a closed system at 150 degrees C with nitric acid, perchloric acid treatment of the digest, reduction of selenium to the tetravalent state with hydrochloric acid followed by Se-2,3-diaminonaphthalene (DAN) complex formation and extraction in a single-step operation. Performance characteristics of the method (accuracy and repeatability) were extensively tested for eleven reference materials and ten practice samples covering both a wide variety of matrices and a wide range of selenium content. Almost all results for reference materials were within the 95% confidence range of the certified value or the best estimate thereof. The coefficient of variation for all samples ranged from 2.3 to 10.1%, average value 4.7%. Average recovery for spiking experiments-levels 0.060, 0.075 and 0.150 micrograms/g was 102%; range 84-114%.