(1) If anionic production of quantum bumps in Limulus photoreceptors is mediated by changes in cyclic nucleotides, then the electrophysiological response of Limulus photoreceptors to tungstate may indicate a role for phosphodiesterase rather than adenylate cyclase in mediating light-induced cyclic nucleotide alterations in this cell.
(2) Film changer angiograms using conventional calcium-tungstate screen combinations.
(3) However, the tungstate effect was not very strong, and the P-2 type tended to change into the P-3.
(4) After staining with hematoxylin-phosphorus-tungstate, the vitelline epithelium of untreated and progesterone-treated rats showed a blue granulation.
(5) The addition of 1 mM tungstate to molybdate-containing media resulted in nearly complete loss of enzyme activity and decreased the intracellular concentration of molybdenum 10-fold.
(6) These studies show that the nontransformed, and the heat-, salt-, and ATP-transformed GRc from the rat liver cytosol can be separated chromatographically, and that the use of tungstate facilitates the resolution of these different receptor forms.
(7) The inactive enzyme obtained from cells grown in the presence of tungstate did not hold Mo but contained 1 mol of W. The content of Fe was not increased.
(8) The constitutive xanthine dehydrogenase and the inducible 2-furoyl-coenzyme A (CoA) dehydrogenase could be labeled with [185W]tungstate.
(9) The level of formate dehydrogenase of C. acidiurici increased 12-fold when 10(-7) M tungstate and selenite were present during growth.
(10) We evaluated six deproteinizing methods for determination of uric acid in serum by "high-performance" liquid chromatography with ultraviolet detection: those involving zinc hydroxide, sodium tungstate, trichloroacetic acid, perchloric acid, acetonitrile, and centrifugal ultrafiltration (with Amicon MPS-1 devices).
(11) Both xanthine dehydrogenase and formate dehydrogenase exhibited the highest level of activity if selenite and tungstate were present in that medium.
(12) Rare earth and barium fluorochloride screen-film combinations of different relative speeds were compared to conventional calcium tungstate systems in patients undergoing excretory urography under controlled conditions.
(13) Single molecules were contrasted with 2 percent potassium silico tungstate which gave better contrast and preservation of enzyme activity than ammonium molybdate.
(14) On the other hand, agents related to VRC and oxoanions of transient metals, such as ribonucleoside, vanadate, molybdate, tungstate and arsenate, exerted no effect on the DNA-cellulose binding ability of the receptor.
(15) Tungstate prevents the formation of NADH-nitrate reductase and FMNH(2)-nitrate reductase activities, but it causes superinduction of NADH-cytochrome c reductase activity.
(16) The results support the idea that NADH-nitrate reductase, FMNH(2)-nitrate reductase and NADH-cytochrome c reductase are activities of the same enzyme complex, and that in the presence of tungstate the 8S enzyme complex is formed but is functional only with respect to NADH-cytochrome c reductase activity.
(17) Rare earth and other new screens absorb a maximum of 1.5 times as much energy and emit twice as much light as comparable calcium tungstate screens.
(18) Furthermore, in vitro cytotoxicity experiments showed inhibition by tungstate of cartilage production in limb bud mesenchymal cultures at concentrations similar to those found in vivo.
(19) We evaluated the physical characteristics and contrast-dose-detail performance of 11 rare-earth and three calcium tungstate screen-film systems.
(20) The transformed and nontransformed GRc were also differentially fractionated by (NH4)2SO4: tungstate-treated (nontransformed) receptor required higher salt concentration and was precipitated at 55% saturation.
Tungstite
Definition:
(n.) The oxide of tungsten, a yellow mineral occurring in a pulverulent form. It is often associated with wolfram.