Showing papers on "Selenium published in 1980"
01 Jan 1980
TL;DR: In this paper, the essential roles of arsenic, fluorine, nickel, silicon, tin and vanadium have in recent years been established in animal nutrition, and they are known as trace elements, minor elements or micro-nutrients.
Abstract: Fifteen or more elements present in rocks and soils normally in very small amounts are essential for plant and/or animal nutrition. By the nature of their low abundance in natural uncontaminated earth materials or plants, they are known as trace elements, minor elements or micro-nutrients. Boron, copper, iron, manganese, molybdenum, silicon, vanadium and zinc are required by plants; copper, cobalt, iodine, iron, manganese, molybdenum, selenium and zinc by animals. In addition essential roles of arsenic, fluorine, nickel, silicon, tin and vanadium have in recent years been established in animal nutrition.
3,339 citations
TL;DR: The selenium uptake and accumulation in tissues of trout reared on diets containing in excess of 3 microgram/g dry feed may ultimately be toxic to trout if maintained over long periods of time.
Abstract: This study measured the dietary selenium requirement of rainbow trout and their response to excessive levels of dietary selenium. A dietary selenium level of 0.07 microgram/g dry feed with a waterborne selenium level of 0.4 +/- 0.2 microgram/liter and a dietary vitamin E level of 0.4 IU/g dry diet was sufficient to prevent frank selenium deficiency symptoms. Maximal plasma GSH.px activity was obtained at a dietary selenium level between 0.15 and 0.38 microgram/g dry feed which is less than the average selenium concentration of commercial diets. Chronic dietary selenium toxicity occurred at 13 microgram selenium/g dry feed. Major effects of selenium toxicity were reduced growth rate, poor feed efficiency and a high number of mortalities. No histopathological lesions or significant deviation in the investigated blood parameters or liver somatic index were detected in trout raised on diets containing 13 microgram selenium/g dry feed. Tissue selenium analysis indicated that trout can maintain homeostasis with dietary selenium levels up to 1.25 microgram/g dry feed. The selenium uptake and accumulation in tissues of trout reared on diets containing in excess of 3 microgram/g dry feed may ultimately be toxic to trout if maintained over long periods of time.
376 citations
TL;DR: The information currently available on the properties and catalytic functions of the four known selenium-dependent enzymes is summarized and formate dehydrogenases of Escherichia coli and several anaerobic bacteria, clostridial glycine reductase, mammalian and avian glutathione peroxidase, and nicotinic acid hydroxylase of Clostridium barkeri are mentioned.
Abstract: Selenium, molecular weight 78.96, resembles sulfur in many of its chemical properties and occurs in inorganic forms as H2Se, H2Se2O3, H2SeO3, and H2SeO4 which are the analogues of hydrogen sulfide, thiosulfate, sulfite, and sulfate, respectively. The commonly available radionuclide, 75Se, is a gamma emitter (half-life 122 days) that is used extensively as a tracer in biochemical studies and as a radiopharmaceutical agent for diagnostic purposes. Organoselenium compounds, in general, are less stable and more reactive than the corresponding sulfur analogues and these properties may account for the toxicity of selenium when it is incorporated indiscriminately in place of sulfur in cellular constituents. On the other hand living systems may have exploited the greater reactivity of certain types of organoselenium compounds in those instances where selenium is specifically required as a component of an enzyme or other macromolecule. Several enzymic processes that do not distinguish selenium from sulfur and therefore may be important in selenium toxicity were discussed in some detail in two earlier reviews on selenium biochemistry (1, 2) and this aspect of the problem is not treated here. Rather, the information currently available on the properties and catalytic functions of the four known selenium-dependent enzymes is summarized. These enzymes are formate dehydrogenases of Escherichia coli and several anaerobic bacteria, clostridial glycine reductase, mammalian and avian glutathione peroxidase, and nicotinic acid hydroxylase of Clostridium barkeri. Additional selenoproteins whose catalytic activities are as yet unidentified are mentioned.
282 citations
TL;DR: Reverse mutation assays with Escherichia coli and Salmonella strains showed that compounds of rhodium, tellurium and platinum are potent mutagens.
Abstract: We carried out rec assays on 127 metal compounds with Bacillus subtilis to check their DNA-damaging capacity and mutagenicity. Certain compounds of beryllium, cobalt, cesium, iridium, osmium, platinum, rhodium, antimony, tellurium, thallium and vanadium were newly found to be positive in addition to those of known positive metals such as arsenic, cadmium, chromium, mercury, molybdenum and selenium. Reverse mutation assays with Escherichia coli and Salmonella strains showed that compounds of rhodium (RhCl3), tellurium (Na2H4TeO6, Na2TeO3) and platinum (PtCl4, (NH4)2PtCl6) are potent mutagens.
265 citations
TL;DR: In this paper, the interactions of selenium with cadmium and mercury were investigated and the authors proposed a method to detect the presence of the two elements in a single sample.
Abstract: (1980). The interactions of selenium with cadmium and mercury. CRC Critical Reviews in Toxicology: Vol. 8, No. 1, pp. 1-42.
247 citations
TL;DR: Selenium, administered to mice with Ehrlich ascites tumors, effectively limited tumor growth and there were no detectable adverse effects to the host.
Abstract: Selenium, administered to mice with Ehrlich ascites tumors, effectively limited tumor growth The response was dependent on the chemical form and dose of selenium administered At the doses administered, there were no detectable adverse effects to the host
168 citations
TL;DR: The methylation process may be an important step in the detoxification process for microorganisms exposed to high concentrations of selenium in sewage sludge and soil.
Abstract: Inorganic selenium compounds are converted to volatile methylated species (dimethyl selenide, dimethyl diselenide, and dimethyl selenone or methyl methylselenite) by microorganisms in sewage sludge and soil. In the absence of added selenium, no volatile selenium compounds were detected. All samples were evaluated without the addition of nutrients and in the presence of air or nitrogen. The methylation process may be an important step in the detoxification process for microorganisms exposed to high concentrations of selenium.
165 citations
162 citations
TL;DR: Results indicate a specific function for selenium in platelet metabolism of essential fatty acids and support the interpretation that these trihydroxy fatty acids arise from breakdown of the primary platelet lipoxygenase product L -12-hydroperoxy-5,8,10,14-eicosatetraenoic acid (12-HPETE).
141 citations
TL;DR: In this article, the reaction sequence for the reduction of in at various surfaces and the formation of selenide films in this medium with and without metal ions present have been investigated by rotating disk and ring disk electrode techniques.
Abstract: The reaction sequence for the reduction of in at various surfaces and the formation of selenide films in this medium with and without metal ions present have been investigated by rotating disk and ring‐disk electrode techniques. The system is complicated by competitive paths leading to selenium formation from Se(−2)‐Se(+4) chemical reactions and the result is sensitive both to the nature of the substrate with the possibility of metal selenide formation and to the concentration of solution species. The implications for cathodic deposition of semiconductors like , from voltammetric and photospectral data, are discussed.
136 citations
TL;DR: The only known functions of vitamin E and selenium are related to the prevention of oxidative damage, so it is possible that their protective effects against heavy metals may involve such functions, thus accounting for the protection afforded by low Levels of the nutrients against high levels of the metal toxicants.
Abstract: It is well established that the toxicity of silver and methylmercury is suppressed by the presence of low levels of vitamin E or selenium in the diet, but little is known of the mechanisms involved. Silver induces a conditioned deficiency of selenium in rats, as shown by its effects on tissue levels of selenium and glutathione peroxidase (a selenoprotein), but methylmercury does not. Supplements of selenium do not decrease mercury levels in tissues of animals given methylmercury, and animals given selenium plus methylmercury may accumulate high levels of mercury without signs of toxicity. Although an equimolar accumulation of selenium and mercury in tissues sometimes occurs and could lead to mutual detoxification, such a coaccumulation is not always linked to protection. The only known functions of vitamin E and selenium are related to the prevention of oxidative damage. It is possible that their protective effects against heavy metals may involve such functions, thus accounting for the protection afforded by low levels of the nutrients against high levels of the metal toxicants.
TL;DR: Overall, the fish responded to selenium exposure at concentrations between 100 and 250 times the normal background concentrations in surface waters but the level of response was low but the blood parameters decreased and the fish appeared to be compensating for these changes by increased erythropoiesis.
Abstract: The 96-h and 9-d LC50s of selenium for rainbow trout (Salmo gairdneri) averaged 8.1 and 6.5 mg∙L−1, respectively. A sublethal exposure of rainbow trout from the newly fertilized egg stage until 44 wk posthatch to 4.4–53 μg∙L−1 of waterborne selenium resulted in a variety of subtle responses. Significantly increased mortality of eyed eggs was observed at selenium concentrations greater than or equal to 28 μg∙L−1 and decreased red blood cell volumes and cellular blood iron at concentrations greater than or equal to 53 and 16 μg∙L−1, respectively. Although the highest eyed egg mortality at 47 μg∙L−1 selenium was double that of control, total mortality was only 6.5%. Similarly, the blood parameters decreased from control levels by a maximum of 30% and the fish appeared to be compensating for these changes by increased erythropoiesis. Overall, the fish responded to selenium exposure at concentrations between 100 and 250 times the normal background concentrations in surface waters but the level of response was ...
TL;DR: In this article, the levels of antimony, arsenic, cadmium, caesium, chromium, cobalt, copper, gold, iron, lanthanum, lead, manganese, mercury, molybdenum, scandium, selenium, silver, tellurium, tin, tungsten and zinc in the kidney, liver and lungs of exposed workers in North Sweden, as well as from a control group, have been assayed quantitatively.
TL;DR: Results indicate that selenide and selenite are more readily metabolized than is selenocysteine to the immediate selenium precursor used for glutathione peroxidase synthesis, and suggest a posttranslational modification at another amino acid residue, rather than direct incorporation of selencysteine, as the mechanism for formation of the presumed selenicysteine moiety of the enzyme.
TL;DR: There was a high mercury concentration in the liver, kidney, and brain samples and Distributions of aluminum, bromine, magnesium, manganese, rubidium, selenium, and vanadium in human body were almost uniform.
Abstract: Neutron activation analysis and instrumental semiconductor gamma-ray spectrometry were used for analysis of 20 trace elements in 10 autopsied human organs and tissues (liver, kidney, cerebrum, cerebellum, heart, muscle, pancreas, spleen, lung, and aorta) from 63 Japanese persons, whose ages ranged from 15 days to 85 yr. Distributions of aluminum, bromine, magnesium, manganese, rubidium, selenium, and vanadium in human body were almost uniform. High concentrations of cadmium were found in kidney and liver samples. There was a high mercury concentration in the liver, kidney, and brain samples. Concentrations of other elements (arsenic, gold, cobalt, chromium, copper, iron, indium, antimony, selenium, titanium, and zinc) in each organ or tissue are also presented in this paper.
TL;DR: Selenium inhibited mammary tumorigenesis without interference of normal reproductive function and weight gain and inhibited the tumor-producing capabilities of only 1 of 4 preneoplastic outgrowth lines maintained in BALB/c (MuMTV-S negative) mice.
TL;DR: An inhibitory effect of pharmacologic levels of dietary selenium on the postinitiation stage of mammary carcinogenesis is suggested.
Abstract: The effect of supplemental dietary selenium on the postinitiation state of N-methyl-N-nitrosourea (MNU)-induced mammary carcinogenesis was investigated in noninbred female Sprague-Dawley rats. Mammary cancer was induced by a single iv injection of MNU. Supplemental selenium feeding was begun 7 days after carcinogen treatment. Feeding of selenium prolonged the latency of mammary cancer appearance and resulted in a reduction in the average number of cancers per rat. The results suggested an inhibitory effect of pharmacologic levels of dietary selenium on the postinitiation stage of mammary carcinogenesis.
TL;DR: In this article, a method for the determination of dissolved selenite and total selenium in natural waters is described, which is based on gas chromatography with an electron-capture detector.
TL;DR: In a 13-wk trial Holstein cows in mid-lactation were fed four diets containing natural selenium alone or supplemented with .1, .2, or .5 mg of inorganic seenium per kilogram of diet, moderate concentrations of dietary selenIUM do not result in toxic amounts of selenarium in milk.
TL;DR: In this article, the simultaneous movement of radiolabeled selenium and mercury was followed in experimental aquatic ecosystems ( tube enclosures) set into a mercury-contaminated lake.
Abstract: The simultaneous movement of radiolabeled selenium and mercury was followed in experimental aquatic ecosystems ( tube enclosures) set into a mercury-contaminated lake. The experimental treatments c...
TL;DR: Observations suggest that glutathione is bound to enzyme selenium by a selenenyl-sulfide linkage (E-Se-SG) which is cleaved by cyanide to release a seenol and S-cyanoglutathione; spontaneous oxidation of the selenol to a labile oxidized form of GSH peroxidase leads to irreversible inactivation.
TL;DR: In this paper, the authors present a study of local order in amorphous and liquid Se 1−x Te x systems with different levels of Tellurium concentration, up to 40% and up to 100% tellurium, respectively.
Abstract: In this paper we present a study of local order in amorphous and liquid SeTe systems. The first part is a neutron scattering study of the Selenium in the amorphous state at room temperature and in the liquid state from the melting point up to 900 C. The Se 1−x Te x mixtures are studied in the amorphous state up to 40% atomic Tellurium and in the liquid state up to 100% Tellurium. The pair correlation function clearly emphasizes the importance of the covalent bonding the divalence of the Selenium and the very sharp 1st and 2nd peaks even at high temperatures and up to 50% Tellurium. Hence in the second part we deal with a quasi-crystalline model already used for the liquid Selenium up to 900 C. A generalization of this calculation to binary systems provides us with a fair simulation of amorphous and liquid Se 1−x Te x systems structure factors. For the lowest concentrations in Tellurium the short range order seems to be mainly substitutional, as far as the Selenium chains are concerned. By increasing the Tellurium concentration the 3-valency of Tellurium in the liquid state produces a chain branching which distorts the Selenium-like structure.
TL;DR: The authors assayed the availability of selenium in feeds and selenomethionine relative to selenum in sodium selenite for restoring blood serum glutathione peroxidase activity in Selenium-depleted chicks.
Abstract: We assayed the availability of selenium in feeds and selenomethionine relative to selenium in sodium selenite for restoring blood serum glutathione peroxidase activity in selenium-depleted chicks. The contents of total selenium (determined by neutron activation analyses) were for eight samples of capelin fish meal, 1.34, two samples of mackerel fish meal, 6.17, one sample of solvent-extracted soybean meal, 0.42, and one sample of corn gluten meal, 0.54 ppm in dry matter. The availability of the selenium (relative to selenium in selenite=100%) in capelin fish meal was 48.0 (38.5--60.0), mackerel fish meal, 34.1 (32.3--35.8), soybean meal, 17.5, corn gluten meal, 25.7, and in selenomethionine, 78.3%.
TL;DR: The contents of the elements antimony, arsenic, cadmium, copper, lead, mercury, selenium, silver, tin and zinc in bone tissue from autopsy specimens of the femur of workers who had been exposed to a large number of metals in a smeltery and refinery in Northern Sweden as well as of a control group have been quantitatively assayed.
TL;DR: In this paper, a method of selenium hydride atomization using a cool highly fuel rich-hydrogen-oxygen diffusion flame burning in the inlet part of a T-shaped quartz tube placed in the optical axis of an atomic absorption spectrometer is investigated.
TL;DR: The results suggest that recution is involved in the conversion of selenium compounds to mutagenic forms and the active mutagens may be selenols, GS-Se- from inorganic seenium and R-Se - from organic selenIUM compounds.
Abstract: Glutathione strongly enhanced the induction of unscheduled DNA synthesis (UDS) in cultured human cells by inorganic selenium compounds: sodium selenate, sodium selenite and sodium selenide. In the presence of 10(-3) M glutathione, high levels of UDS (74-114 grains per nucleus) were observed in cells treated with (i) selenate at 10(-3) M, (ii) selenite at 10(-5)-3 X 10(-4) 7, and (iii) selenide at 10(-5)-10(-3) M. Glutathione at 10(-3) M also enhanced the clastogenic and cytotoxic effects of selenite and selenate in Chinese hamster ovary (CHO) cells. Glutathione at 10(-4) M or 10(-2) M caused less enhancement of DNA damage and toxicity in both the UDS and chromosome aberration assays. In the absence of glutathione, these inorganic selenium compounds induced low levels of UDS (up to 13 grains per nucleus) and moderate frequencies of chromosome aberrations (up to 11%). 3 organic selenium compounds (selenocystine, selenocystamine and selenomethionine) were also examined for the induction of UDS. No unscheduled DNA synthesis was detected in cells treated with selenocystamine or selenomethione, with or without added glutathione. However, selenocystine alone at 10(-4)-10(-3) M induced a low level of UDS; glutathione enhanced the DNA-damaging effect of selenocystine. The maximum amount of UDS (22 grains/nucleus) occurred in the presence of 10(-2) M glutathione. This was about one-fifth of that detected in cells treated with inorganic selenium compounds and 10-fold lower concentrations of glutathione (10(-3) M). The results suggest that recution is involved in the conversion of selenium compounds to mutagenic forms. The active mutagens may be selenols, GS-Se- from inorganic selenium and R-Se- from organic selenium compounds.
TL;DR: An i.p. diethylmaleate injection decreased the endogenous Cu and Zn excretion in rat bile to 20 and 50 per cent, respectively, which suggests that copper, at least partly, is excreted in the bile as a glutathione complex or by other glutATHione-dependent mechanisms.
TL;DR: In this article, a simple procedure is described for reducing the chemical interference of heavy metal ions with the hydride, which is achieved through the formation of stable chlorocomplexes of these ions in 7.5 M HCl.