Showing papers on "Selenium published in 1969"
TL;DR: The physiological differentiation within the genus Astragalus (one of the best known accumulators) is discussed, and the relationships between sulfur and selenium metabolism are discussed, along with the possible role of selenum as a micronutrient.
Abstract: Several species of higher plants accumulate selenium. The association of accumulator species with seleniferous soils is described. The physiological differentiation within the genus Astragalus (one of the best known accumulators) is discussed. Biochemical differentiation between Astragalus species and the assimilation of selenium by other taxonomic groups are detailed and tabulated. The relationships between sulfur and selenium metabolism are also discussed, along with the possible role of selenium as a micronutrient. 84 references, 4 figures, 8 tables.
177 citations
171 citations
TL;DR: Sodium selenite which is not teratogenic under similar conditions does provide significant protection against the malformations induced by cadmium or arsenic when injected simultaneously with either of these teratogens.
Abstract: Cadmium sulfate and sodium arsenate injected into pregnant hamsters are independently teratogenic. Sodium selenite which is not teratogenic under similar conditions does provide significant protection against the malformations induced by cadmium or arsenic when injected simultaneously with either of these teratogens. The effect of a time interval between the injection of cadmium and selenium revealed that the protective effect of selenium was still marked at a 30-minute interval but decreased markedly at two- to four-hour intervals. At the 30-minute interval the protective effect was more marked when the selenium was injected first rather than the reciprocal method.
139 citations
TL;DR: It seems most likely that the major urinary detoxification metabolite of selenite is trimethyl selenide, which was isolated from rat urine by ionexchange chromatography and precipitation as the reineckate salt.
128 citations
TL;DR: A new selenium metabolite was isolated from the urine of rats injected with Selenite, identified as a trimethylselenonium ion, a normal excretory product of selenite selenum.
121 citations
112 citations
TL;DR: Arsenic improved the growth of rats chronically poisoned by selenium, largely prevented the liver damage caused by seenium, and decreased the amount of selenum retained in the tissues.
85 citations
TL;DR: With the elemental selenium a small increase in concentration in the plants was found in both kinds of experiments with red clover, lucerne, mustard, and sugar beet as test plants, but not with barley.
Abstract: Elemental selenium and a series of selenites and selenates were applied in pot and field experiments. With the elemental selenium a small increase in concentration in the plants was found in both kinds of experiments with red clover, lucerne, mustard, andsugar beet as test plants, but not with barley. In the second year an increase in the concentration in the plants was found in lucerne only (field experiment). In a pot experiment eight successive cuts of clover all had nearly the same content.
82 citations
70 citations
TL;DR: The extent of reduction is reported as a function of the concentrations of the sulfhydryl compounds, and equilibrium constants are given, and the implications are discussed in terms of their possible significance to the function of selenium in biological systems.
61 citations
Journal Article•
TL;DR: 75Se released from cells is bound by a plasma protein but can be removed from the protein by treatment with cysteine, and studies suggest that the released selenium is in an altered form or state, although this product has not been characterized.
Abstract: When 75Se, as selenite, is added to human blood it is rapidly taken up by the cells (50–70% within 1–2 min) and is then released into the plasma so that most of the radioactivity is in the plasma by 15–20 min. Uptake is inhibited by 10−3 M cyanide. The release of radioactivity from the cells is inhibited by 10−3 M para-chloromercuribenzoate and by 10−3 M iodoacetamide, although these agents do not affect uptake. Azide and 2,4-dinitrophenol (at 10−3 M) do not affect either process. Large quantities of sulfite, sulfate, and selenate (1000 times as much S or Se as 75Se) do not affect uptake or release, but large amounts of selenite (1000 times) inhibit release. The release rate follows first-order kinetics and increases with temperature. 75Se released from cells is bound by a plasma protein but can be removed from the protein by treatment with cysteine. Studies suggest that the released selenium is in an altered form or state, although this product has not been characterized. A hypothetical pathway for the m...
TL;DR: The isotopic composition of krypton extracted from six different selenium ores gives clear evidence for the double beta-decay of 82 Se as mentioned in this paper, and the preliminary half-life of 82 SE, calculated from one sample, is 1.4 × 10 20 y with an error of about 20%.
TL;DR: A method is proposed for the determination of selenium in plant materials at levels as low as 0·005 p.p.m. in dried material.
Abstract: The determination of very small amounts of selenium in plant samples with 2,3-diaminonaphthalene has been investigated. Losses of selenium are prevented by a controlled wet-oxidation procedure in a silicone bath. A method is proposed for the determination of selenium in plant materials at levels as low as 0·005 p.p.m. in dried material.
TL;DR: Heavy pellets in which the source of selenium was calcium selenite, barium selenate, or elemental selenum have enhanced blood and tissue selenarium levels for periods up to 12 months, when dosed singly to sheep grazing pastures of normal selenIUM status.
Abstract: Heavy pellets in which the source of selenium was calcium selenate, barium selenate, or elemental selenium have enhanced blood and tissue selenium levels for periods up to 12 months, when dosed singly to sheep grazing pastures of normal selenium status. The components of choice were finely divided metallic iron and elemental selenium possibly in the proportion of 20 : 1.
TL;DR: Results show that these compounds have an action similar to, and sometimes even superior to, that of cysteine, and the ability of the compounds to alleviate the mortality and the leukopenia occurring in rats exposed to irradiation.
Abstract: This paper deals with the radioprotection afforded by selenocystine, selenomethionine, colloidal selenium, selenoxanthene, selenoxanthone, and selenochromone in living rats. Our evaluation of radioprotection was based on the ability of the compounds to alleviate the mortality and the leukopenia occurring in rats exposed to irradiation of 600, 750, and 900 R. The results show that these compounds have an action similar to, and sometimes even superior to, that of cysteine. A preliminary study was made of the mechanism of action of the selenium derivatives by measurement of the retention of selenium in the blood, and its distribution at the subcellular level in the liver.
TL;DR: Results of two studies using practical and purified type diets with chickens showed that treatments involving selenium additions at a sub-toxic level, i.e. 2 p.p.m., was found to improve the growth rate of chicks on a practical diet.
TL;DR: The selenium content of over 120 fossil-fuel samples from various areas in the United States have been determined using neutron activation analysis combined with extractive distillation of selenIUM as mentioned in this paper.
Abstract: The selenium content of over 120 fossil-fuel samples from various areas in the United States have been determined using neutron activation analysis combined with extractive distillation of selenium...
TL;DR: In this article, a study of the fragment negative ions formed by electron impact on the hexafluorides of sulphur, selenium and tellurium has been made.
TL;DR: Selenium concentrations were determined at various stages of gestation in the bodies and fetal tissues of 26 ewes fed a nutritional muscular dystrophy (NMD) producing hay for 2 years.
Abstract: Selenium concentrations were determined at various stages of gestation in the bodies and fetal tissues of 26 ewes fed a nutritional muscular dystrophy (NMD) producing hay for 2 years. Eight of these ewes were injected intramuscularly with 6 mg selenium 10 days before slaughter. Maternal tissues in general contained more selenium than the corresponding fetal tissues. As might be expected, the injection of selenium enhanced tissue concentrations in both ewes and fetuses. The pattern of selenium concentration in the various tissues was similar in dams and fetuses, with kidneys containing highest amounts. Selenium concentrations in the tissues of both ewes and fetuses did not appear to change with the stage of gestation. A single oral dose of radiotocopherol was administered to each of 10 pregnant ewes which had been fed an NMD-inducing hay for 2 years. Animals were slaughtered at 1, 2, 5, and 13 days after the oral dose of vitamin E. It was found that in the ewes, liver and adrenal tissues had a high rate of...
TL;DR: The reason was uncovered for previous failures to obtain reproducible color values for selenocystine and the diselenide-sulfhydryl and diselanide-selenol interchange reactions, which occur over a wide pH range, must be taken into account during analytical investigations involving mixtures ofdiselenides, and/or thiols, and-or selenols.
Abstract: The reactions of selenium and tellurium with lithium, sodium, potassium, and tetramethylammonium borohydrides have been examined, using the hydrogen evolution as a measurement of the replacement of...
01 Jan 1969