(n.) A nonmetallic element of the sulphur group, and analogous to sulphur in its compounds. It is found in small quantities with sulphur and some sulphur ores, and obtained in the free state as a dark reddish powder or crystalline mass, or as a dark metallic-looking substance. It exhibits under the action of light a remarkable variation in electric conductivity, and is used in certain electric apparatus. Symbol Se. Atomic weight 78.9.
Example Sentences:
(1) It was tested for recovery and separation from other selenium moieties present in urine using both in vivo-labeled rat urine and human urine spiked with unlabeled TMSe.
(2) Dietary factors affect intestinal P450s markedly--iron restriction rapidly decreased intestinal P450 to beneath detectable values; selenium deficiency acted similarly but was less effective; Brussels sprouts increased intestinal AHH activity 9.8-fold, ECOD activity 3.2-fold, and P450 1.9-fold; fried meat and dietary fat significantly increased intestinal EROD activity; a vitamin A-deficient diet increased, and a vitamin A-rich diet decreased intestinal P450 activities; and excess cholesterol in the diet increased intestinal P450 activity.
(3) Mice exhibiting this suppression of immunity had levels of blood glutathione peroxidase, serum selenium, and liver DNA, RNA and protein similar to mice receiving selenium only.
(4) Excess levels of selenium (2.5 and 5 ppm) in the vitamin E-deficient diet had little or no effect on spleen size or hematocrit of rats not receiving lead, but partially prevented the splenomegaly and anemia of red cells from either non-poisoned or lead-oisoned vitamin E-deficient rats, but not as effectively as vitamin E. These results show that vitamin E status of rats is more important that selenium status in determining response to toxic levels of lead.
(5) Plasma selenium concentration and glutathione peroxidase activity in the subjects who died within 1 year of screening were 89% and 88%, respectively, of the values among survivors (p less than 0.01).
(6) Although selenium deficiency in livestock is consequently now rare in Oregon, selenium-deficient soils and attendant selenium deficiency conditions have been reported near the Kesterson Wildlife Refuge in the Northern part of the San Joaquin Valley, California, where, paradoxically, selenium toxicity in wildfowl, nesting near evaporation ponds, occurred and attracted wide attention.
(7) The synthetic "C" nucleoside, tiazofurin (2-beta-D-ribofuranosylthiazole-4-carboxamide), its selenium analogue selenazofurin, and the related inhibitor of inosine 5'-phosphate (IMP) dehydrogenase, mycophenolic acid, are effective inducers of the terminal differentiation of HL-60 promyelocytic leukemia cells.
(8) Thus, in this population with intermediate selenium intake, low serum selenium is not associated with an excess risk of myocardial infarction.
(9) Liver, blood, kidney and lungs were found to contain most of the selenium, here also a two-phased elimination was observed.
(10) These findings suggest that neither serum levels of selenium nor those of retinol have an appreciable effect on the risk of cancer.
(11) The incidences of esophageal tumors were statistically not significant among rats on normal, high and low selenium intake (P greater than 0.05).
(12) Alteration of guinea pig erythrocyte superoxide dismutase activity by the dietary antioxidants ascorbic acid and selenium was investigated.
(13) The more severe was the PIH the lower was the selenium level.
(14) Significantly lower selenium values were observed in blood from colorectal cancer patients than from normal individuals (0.1349 ppm vs. 0.1502 ppm.
(15) Selenium-deficient rats were used to examine the nature of the oxidant stress.
(16) Although treatment with beta-carotene tended to decrease the incidence and number of large intestinal carcinomas, beta-carotene, selenium, esculin and eugenol all decreased the incidence of kidney nephroblastomas, the differences were not statistically significant.
(17) These studies were designed to measure leukotriene B4 (LTB4) production by polymorphonuclear leukocytes (PMN) from selenium (Se)-deficient and Se-adequate goats.
(18) Copper deficiency impairs cell-mediated immunity, as does selenium deficiency when it is associated with vitamin E lack.
(19) Many forms of selenium supplement are commercialized.
(20) The possibility that a sub-clinical deficiency of the trace element selenium might exist in a sample of the British population was examined by giving a selenium supplemented for 5 weeks.
Sulfur
Definition:
Example Sentences:
(1) Manometric studies with resting cells obtained by growth on each of these sulfur sources yielded net oxygen uptake for all substrates except sulfite and dithionate.
(2) Typically the iron-iron axis (gz) of the binuclear iron-sulfur clusters is in the membrane plane.
(3) Our study suggests that a major part of the renal antimineralocorticoid activity of spironolactone may be attributable to minor sulfur-containing metabolites or their precursors having a high renal clearance that affords access to their site of activity via the renal tubular fluid.
(4) Ferredoxin reductase (Fd-reductase) supplies reducing equivalents obtained from NADPH to mitochondrial cytochrome P450 enzymes via the small iron-sulfur protein ferredoxin.
(5) The loss of enzyme activity in sulfur-rhodanese does not involve cysteinyl residues but can be correlated with the modification of guanidino groups, notably that of Arg-186, the side chain of which may play a role in substrate binding.
(6) In two patients with extensive marrow necrosis, the diagnosis of marrow necrosis was established by morphologic and radioisotopic studies, and the extent of involvement was accurately assessed by marrow scanning with technetium Tc 99m sulfur colloid while the patients were still alive.
(7) It was presumed that thymohydroquinone is excreted as ethereal sulfuric acid conjugate in man.
(8) Also purple sulfur bacteria lowered BOD levels as demonstrated by the growth of T. floridana in sterilized sewage.
(9) An equivalent maximum growth response of rats fed L-methionine or N-acetyl-L-methionine was obtained when the total dietary sulfur amino acids compromised 0.36-0.41% of the diet.
(10) Histopathological evaluations showed that sulfuric acid particles alone did not cause inflammatory responses in centriacinar units of rat lung parenchyma (expressed in terms of percent lesion area) but did cause significant damage (cell killing followed by a wave of cell replication) in nasal respiratory epithelium, as measured by uptake of tritiated thymidine in the DNA of replicating cells.
(11) Ac-MPS of the hyaluronic acid type prevail in the ground substance of the myxoid and fibroblastic mesenchyma, while the substances containing sulfuric groups predominate in the tissue matrix exhibiting fibrogenic tendencies.
(12) Previous work demonstrated a differential decrease in iron-sulfur centers A, B and X which indicated that center X serves as a branch point for parallel electron flow through centers A and B (Golbeck, J.H.
(13) Our observation leads to the suggestion that, in vivo, either rhodanese is maintained in its more stable sulfur-substituted form or cellular compartmentalization prevents inactivation by nitrite.
(14) In contrast, the (Rp)-isomers, which have an equatorial exocyclic sulfur atom, bound to the enzyme without stimulation of its activity.
(15) A strong shoulder was observed at 2481.7 eV on the low-energy side of the sulfate absorption edge, deriving from a novel type of sulfur having a slightly lower oxidation state than sulfate sulfur.
(16) Long-term treatment with furosemide (up to 13 months) caused transient changes in the elemental content of the pancreatic acinar cells: a decrease in chloride and sulfur, and an increase in phosphorus, potassium and magnesium.
(17) The iron-sulfur proteins of the green photosynthetic bacterium Chlorobium have been characterized by oxidation-reduction potentiometry in conjunction with low-temperature electron paramagnetic resonance spectroscopy.
(18) The reaction is based on the reduction of sulfur dioxide at a dropping mercury electrode.
(19) Proton induced X-ray emission (PIXE) analyses were performed on single hair fibers in triplicate from 103 individuals in order to determine sulfur, zinc, calcium, and chlorine content.
(20) In a survey of the proteins from human hair, a genetic electrophoretic variant has been observed in the high-sulfur protein region.