Impact of high bromide intake in the rat dam on iodine transfer to the sucklings.

A significant impact of high bromide levels in the organism of the mother on iodine transfer to the sucklings was established in experiments with female Wistar rats. The observed decrease in iodine transfer to the young through mothers' milk and/or an increase in the bromide concentration in the milk, caused a decrease in body weight of the pups. Enhanced bromide levels also adversely affected the thyroid gland of the young.

High bromide intake affects the accumulation of iodide in the rat thyroid and skin.

The effect of a high bromide intake on the kinetics of iodide uptake and elimination in the thyroid and skin of adult male rats was studied. In rats fed a diet with sufficient iodine supply (> 25 microg I/d), the iodide accumulation in the skin predominated during the first hours after 131I iodide application. From this organ, radioiodide was gradually transferred into the thyroid.

Effect of high bromide levels in the organism on the biological half-life of iodine in the rat.

In experiments on rats, a significant influence of an extraordinarily high bromide intake on the whole-body biological half-life of iodine was established. Very high bromide intake (1) decreased the amount of radioiodide accumulated in the thyroid, (2) changed the proportion between the amount of iodine retained in the thyroid and the total amount of absorbed iodine, (3) significantly shortened the biological half-life of iodine in the thyroid from approximately 101 h to 33 h in animals maintained on an iodine-sufficient diet and from 92 h to about 30 h in rats fed a low-iodine diet, and (4) changed the time-course (added a further phase) of iodine elimination from the body. These changes were caused, with high probability, by an increase of iodine elimination by kidneys due to an excess of bromide.

Bromide kinetics and distribution in the rat. II. Distribution of bromide in the body.

The distribution of 82Br-bromide in 15 different organs and tissues of rats has been determined by high-resolution gamma-ray spectrometry and by the scintillation counting technique at different times after the application of Na 82Br, either by subcutaneous injection or by continuous administration in the drinking water. The amount of 82Br-bromide in the various tissues reached its largest uptake within a few hours, and the concentration ratio of 82Br in the tissues to blood remained practically constant between 8 and 396 h after the application. The whole stomach of rats was the only organ of those investigated that had a larger uptake of 82Br than blood.

Bromide kinetics and distribution in the rat. I. Biokinetics of 82Br-bromide.

Biological half-lives of bromine in 15 different organs and tissues of the rat, in addition to the whole-body half-life, were determined by measuring the radioactive concentration of 82Br-bromide in samples of tissues collected at the time intervals of 12-396 h from animals that continuously (up to 17 d) received 82Br-labeled bromide in their drinking water. The half-life values, calculated from the experimental data by the method of gradual estimates of the parameters in question with the SPSS statistical program, ranged from 94.3+/-14.

Biological half-life of bromine in the rat thyroid.

The biological half-life of bromine in the rat thyroid was determined by measuring the radioactivity of thyroids of animals which continuously received 82Br labelled bromide in their food. The value of this half-life (110 h) is practically the same as the biological half-life of iodine. The rate of establishing the I/Br concentration ratio in the thyroid depends on the biological half-life of bromine.

Effect of increased bromide intake on iodine excretion in rats.

The time course of iodine excretion in adult male rats substantially differs from bromine excretion. Bromine is excreted at a single rate, whereas iodine evinces two excretion rates. Even a strong increase in bromide intake in experimental animals failed to affect the rate of iodine excretion but it lowered the fraction of iodine accumulated in the thyroid gland by 20% probably by affecting the transport of iodide into the thyroid gland.

Interaction of bromine with iodine in the rat thyroid gland at enhanced bromide intake.

In experiments with rats, we have found that at enhanced intake of bromide, bromine does not replace chlorine in the thyroid; it replaces iodine. Under our experimental conditions, more than one-third of the iodine content in the thyroid was replaced by bromine. In the thyroid, bromine probably remained in the form of bromide and, in proportional to its increased concentration, the production of iodinated thyronines decreased, with the sum of the iodine and bromine concentrations being constant at the value of 20.

Study of distribution and interaction of arsenic and selenium in rat thyroid.

Seventy-eight Wistar weanling rats were pretreated with arsenate (100 mg/L As), selenite (1 mg/L Se), and arsenate (100 mg/L As) plus selenite (1 mg/L Se) added to the drinking water. After 4 w, all the animals were sacrificed and serum T3 and T4 were determined by double-antibody radioimmunoassay. Thyroid tissue concentrations of As and Se were determined in female rats by neutron activation analysis, and tissue specimens were examined histopathologically.

Vanadium levels in urine and cystine levels in fingernails and hair of exposed and normal persons.

Vanadium was determined by radiochemical neutron activation analysis (RNAA) with proven accuracy in urine of workers occupationally exposed to vanadium-rich dust in a vanadium pentoxide production plant, and values in the range of 3.02-762 ng/mL (median 33.0 ng/mL) were found.

Effects of orally administered vanadium on the immune system and bone metabolism in experimental animals.

Experiments were carried out to gain more information on the effects of long term exposure to low doses of vanadium administered to mice and rats in drinking water. The selective immunotoxic effects of vanadium were depression of phagocytosis, splenotoxicity, enlargement of spleen, elevation of peripheral blood leucocytes and T and B cell activation. Vanadium accumulates in hard tissues and influences the mineralisation of epiphyseal cartilage.

Vanadium levels in hair and blood of normal and exposed persons.

Vanadium was determined by both instrumental neutron activation analysis (INAA) and NAA with radiochemical separation (RNAA) in hair of normal children and of children potentially exposed by accidental drinking of vanadium contaminated water (long-term, low-dose exposure). Vanadium hair levels in the two groups did not differ significantly and were in the range 46-313 micrograms/kg (median 98 micrograms/kg) and 24-235 micrograms/kg (median 88 micrograms/kg for the normal and exposed groups, respectively. Using RNAA with proven reliability at the ultratrace level, vanadium was determined in whole blood of the exposed and normal children, normal adults and workers professionally exposed to vanadium in a factory producing vanadium pentoxide.

Structural analogy among mammalian spectrins and spectrin-like proteins revealed by molybdenum labeling.

Pentavalent complex of 99Mo with ascorbic acid binds in vitro to the plasma membranes of human, rabbit, rat and mouse red cell membranes and to bovine synaptic and rat intestinal brush border membranes. Red cell spectrins and spectrin-like proteins from non-erythroid cells were determined as the molybdenum-binding proteins in the membranes. Specificity of this binding among all membrane proteins suggests structural analogy in this group of proteins.

Reticulocyte-dependent labeling alterations of red cell membrane in pyruvate kinase deficiency anemia.

The radioactive labeling of spectrin using the pentavalent complex of molybdenum-99 was applied to the study of membrane protein in pyruvate kinase deficient red cells. Compared to the control, the labeling profile of the enzymopathic red cell membrane proteins remained generally unchanged but the molybdenum uptake was found to depend largely on the reticulocyte count. This finding may reflect changes during the cell maturation.

The mechanism of action of molybdenum and tungsten upon collagen structures in vivo.

The effect of in vivo administration of molybdenum (as sodium molybdate) and tungsten (as sodium tungstate) was investigated in the skin of laboratory rats. It was proved that the amount of both bound molybdenum and tungsten in collagen is relatively small being 0.05 and 0.

Specific molybdenum binding to spectrin subunits.

Molybdenum in the form of its pentavalent complex binds primarily to spectrin when incubated with erythrocytes. Only the band 1 subunit is involved in this interaction thus indicating some structural differences between spectrin subunits.

Effects of molybdenum on the organism (a review).

Molybdenum belongs to a group of essential microelements and occurs in all components of the environment. Major Mo sources for man are foods, especially vegetable, to a lesser extent drinking water. Its metabolism is primarily influenced by interaction with other metals, specifically copper and iron.

Effects of dietary zinc, manganese, and copper on tissue accumulation of cadmium by Japanese quail.

The beneficial effects of a combined dietary supplement of Zn, Cu, and Mn in decreasing Cd absorption was previously reported. The purpose of this study was to investigate the individual and combined effects of these three elements. In the first two experiments, day-old Japanese quail were fed basal diets containing either requirement amounts of Zn (30 ppm) and Mn (12 ppm) and slightly above requirement levels of Cu (5 ppm).

Unchanged binding of 99molybdenum to red cell membrane proteins in hereditary spherocytosis.

The interaction of 99Mo with red cell membrane proteins was found specific for spectrin both in normal red cells and those of hereditary spherocytosis. In addition, no significant quantitative differences were observed in labeling patterns between these two types of red cells, thus indicating no major alterations in the spectrin molecules of hereditary spherocytosis.

Interaction of molybdenum with human erythrocyte membrane proteins.

This study describes the interaction of molybdenum with blood components. Molybdenum-99 was added to blood, and after four washings, 3% of the total radioactivity was found in red cells. More specifically, the radioactivity was determined to be associated with the cell membrane.