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Query: UMLS:C0027960 (mole)
 21,279 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

With increasing amounts of electroinactive amitriptyline, each of the three chlordiazepoxide reduction waves shifted to more cathodic half-wave potentials and decreased in limiting current. The shift was most pronounced up the 1:1 mole ratio but continued up to ratios of 200:1. This behavior was observed in several supporting electrolytes and was not due to change in pH since this factor was maintained constant as the amitriptyline concentration was increased. Shifts in E1/2 and reductions in limiting current may arise in several ways, such as complex formation between the two drugs or adsorption of the amitriptyline onto the surface of the dropping mercury electrode hindering chlordiazepoxide reduction. Most data point to adsorption as the cause.
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PMID:Effect of amitriptyline on polarography of chlordiazepoxide. 69 Aug 38

The effect of incubation with mercury (Hg) as HgCl2 and cadmium (Cd) as CdCl2, at levels of 6 or 12 micrograms/ml of medium, on explants of term human placental microvillus membrane fluidity were studied. After incubation for 6 or 24 hr explants for each dose level were pooled and washed with fresh medium to remove any unbound metal. Placental membranes were separated by differential centrifugation and fluidity was studied by steady-state fluorescence polarization, expressed as the fluorescence anisotropy, r, with 1,6-diphenyl-1,3,5-hexatriene as a probe. The results show that membranes derived from explants incubated for 24 hr with either 6 or 12 micrograms/ml medium of either metal showed fluorescence anisotropy values (i.e., decreased fluidity) significantly higher than that of their respective controls. With 6 micrograms/ml of either metal the decrease in fluidity was highly significant for both metals and with 12 micrograms/ml a further decrease in membrane fluidity was observed with either metal. Both metals accumulated in placental membranes in proportion to their level in the medium. Membrane accumulation of Cd was higher than that of Hg. The cholesterol, phospholipid, and cholesterol-to-phospholipid mole ratios in membranes derived from metal-treated explants were unchanged, compared to their respective controls. However, no changes in membrane fluidity were observed in the samples incubated for 6 hr. In conclusion, exposure of placental cells to Hg and Cd caused accumulation of the metals in the membranes and lowered the membrane fluidity, which may affect membrane function and cause damage to the developing fetus.
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PMID:In vitro exposure to mercury and cadmium alters term human placental membrane fluidity. 152 49

In an attempt to understand the chemistry of the light-induced staining of children's teeth by tetracycline, we studied the photo-chemical behavior of tetracycline adsorbed on hydroxyapatite, as a simple model of enamel. Tetracycline was strongly bound by hydroxyapatite to give a pale yellow material which, under ultraviolet light, showed a bright yellow fluorescence (lambda max 525 nm). On exposure of this material to the radiation from a medium-pressure mercury lamp, the fluorescence gradually disappeared, and a red-purple product was formed. Photo-acoustic spectroscopy was employed to follow the disappearance of tetracycline and the concomitant formation of the red-purple product, the spectrum of which (lambda max 530 nm) led to the conclusion that it was 4 alpha, 12 alpha-anhydro-4-oxo-4-dedimethylaminotetracycline (AODTC). This assignment was supported by the observation that 1 mole of oxygen was absorbed per mole of adsorbed tetracycline converted to the red-purple product. It is suggested that the formation of AODTC on hydroxyapatite probably takes place by a mechanism of photo-oxidation similar to that already proposed for solutions of tetracycline, and that the formation of AODTC in children's teeth is responsible for the light-induced staining caused by tetracycline.
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PMID:Photo-oxidation of tetracycline adsorbed on hydroxyapatite in relation to the light-induced staining of teeth. 298 27

Glutathione peroxidase (GSHPx), (glutathione:H2O2 oxidoreductase, EC 1.11.1.9) was purified to homogeneity from human plasma. This resulted in a 6800-fold purification of the enzyme with a 2.8% yield. The purification process involved ammonium sulfate fractionation, DEAE-cellulose batch and column chromatographies, hydroxyapatite, and Sephadex G-200 and DEAE-Sephadex A-25 chromatographies. The major peak on DEAE-Sephadex A-25 column chromatography was found to be homogeneous on polyacrylamide gel electrophoresis in the presence or absence of sodium dodecyl sulfate (SDS). Relative mobility in nondenaturing polyacrylamide gel electrophoresis at pH 8.2 was 0.5 for the purified enzyme as detected by both protein staining and enzyme activity compared with 0.38 for erythrocyte GSHPx. The molecular weight of the plasma enzyme as determined by gel filtration was found to be approximately 100,000. SDS-gel electrophoresis of the plasma enzyme gave a subunit molecular weight of approximately 23,000. This suggests that the plasma enzyme exists as a tetramer in its native state, similar to that seen for the erythrocyte enzyme, but with slightly different mobility on SDS-gel electrophoresis. Plasma GSHPx, like the erythrocyte enzyme, was found to contain approximately four atoms of selenium per mole of protein. Utilizing iodinated concanavalin A, it was found that plasma GSHPx, but not the erythrocyte GSPx, is a glycoprotein. Purified plasma enzyme catalyzes both the reduction of tertiary butyl hydroperoxide and hydrogen peroxide. The apparent Km of plasma GSHPx for GSH is 5.3 mM and for tertiary butyl hydroperoxide it is 0.57 mM. Copper, mercury, and zinc strongly inhibit the enzyme activity of plasma GSHPx. Rabbit antibodies directed against the human erythrocyte GSHPx do not precipitate the enzyme activity of the purified plasma enzyme. Radioimmunoassay utilizing erythrocyte GSHPx and anti-erythrocyte GSHPx antibodies showed that less than 0.13% of the antigenically detectable protein is found in the purified GSHPx from plasma.
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PMID:Purification and characterization of human plasma glutathione peroxidase: a selenoglycoprotein distinct from the known cellular enzyme. 361 51

By the dynamics of human oxyhemoglobin coagulation in the presence of phenyl mercury acetate in tris-AcOH buffer, pH 7.2 the number of moles of PhHg+ stechiometrically bound with protein at different temperatures was estimated. Within the temperature range 15-30 degrees C this value is constant--32-34 mole per 1 mole of HBO2-tetramer. Within the range 30-40 degrees C it rises to approximately 40. Coagulation of oxyhemoglobin modified with PhHg+ cation is reversible in contrast to HBO2 coagulation modified with uncharged PhHgCl.
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PMID:[Effect of phenylmercury derivatives on human oxyhemoglobin]. 381 39

1. This paper describes an attempt to learn more about the binding of Hg(2+) to tissues at pharmacological concentrations of this metal. Other methods were not applicable to such low concentrations of mercury. 2. The method involved equilibrium dialysis of Hg(2+) against 1% homogenates of rat kidney or liver in the presence of penicillamine. Two classes of mercury-binding sites were observed, one class having a chemical affinity for mercury 100-fold greater than the other class. The binding capacities of the class of higher and lower affinity were respectively 1.0x10(-7) and 30x10(-7)mole of mercury/g. wet wt. of tissue. The same classes of binding sites were found in both liver and kidney homogenates. 3. The binding sites of both classes reacted with only one valency of Hg(2+), the other valency forming a bond with penicillamine. Thus the total binding capacities of both classes are equivalent to 50% of the total reactive protein-bound thiol groups in the homogenate. 4. The results eliminate three possible mechanisms for the preferential accumulation of mercury by kidney. They support the idea that the permeability changes in kidney cells resulting in diuresis are similar to the permeability changes produced on the membranes of other mammalian cell species by mercury.
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PMID:Studies on the binding of mercury in tissue homogenates. 596 62

Two cytoplasmic cadmium-binding glycoproteins from the hepatopancreas of a whelk, Buccinum tenuissimum, were purified to homogeneity by Sephadex G-75 gel filtration and two DEAE-Sephadex A-25 chromatographies in the presence of 2-mercaptoethanol. These two cadmium-binding glycoproteins, termed FIIA and FIIB, each showed a single band after electrophoresis on 10% polyacrylamide gel at pH 8.9. The molecular weight of FIIA was estimated as 8000 and that of FIIB as 13000 by SDS-polyacrylamide gel electrophoresis. Based on molecular weights of 6500 and 11900 for the protein moiety of FIIA and FIIB, respectively, the total number of amino acid residues was 52 in the former and 94 in the latter. Three and two cysteine residues in FIIA and FIIB, respectively, were titratable with p-chloromercuribenzoate. FIIB also contained two more half-cystine residues. The sugar contents of FIIA and FIIB were about 20.5% and 8.7% by weight, respectively, consisting of galactose, mannose, fucose and amino sugar. The purified glycoproteins FIIA and FIIB contained about 0.6% and 1.0% cadmium by weight, respectively, and both showed strong metal-binding capacity, especially for cadmium, copper and mercury. The apparent cadmium dissociation constants for FIIA and FIIB after treatment with 2-mercaptoethanol were 7.3 X 10(-6) and 9.1 X 10(-7) M, respectively. Cadmium contents at saturation were nearly 6 and 8 gatom per mole for FIIA and FIIB, respectively.
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PMID:Purification and molecular properties of two cadmium-binding glycoproteins from the hepatopancreas of a whelk, Buccinum tenuissimum. 684 39

A 27-year-old woman presented with a distinct gray-blue coloration of the left eye and the periorbital region. The right periorbital region also displayed minimal pigmentation. It was established that eye drops containing mercury had been administered for some years. Initially hydargyrosis was considered as an etiologic factor. Finally we arrived at the diagnosis of nevus of Ota on conjunction with a blue nevus on the forehead. The simultaneous occurrence of a nevus of Ota and the blue nevus suggest a common basic developmental disturbance. The nevus of Ota represents a benign dermal hyperpigmentation syndrome and has to be differentiated from melanosis bulbi.
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PMID:[Nervus of ota (author's transl)]. 734 28

A comparison in mice has been made of the effectiveness of five chelating agents used clinically for acute mercuric chloride poisoning, or recommended for such use. The compounds examined were N-Acetyl-D,L-penicillamine (NAPA), D-penicillamine (DPA), 2,3-dimercaptosuccinic acid (DMSA), sodium 2,3-dimercaptopropanesulfonate (DMPS), and 2,3-dimercaptopropanol-1 (BAL). The test of effectiveness was their ability to reduce the mortality of acute mercuric chloride poisoning when administered 20 minutes after the mercury at chelate:mercury mole ratios of 10, 15, 20, and 30. All except BAL were found to be effective at the highest mole ratio tested, but N-Acetyl-D,L-penicillamine and sodium 2,3-dimercaptopropanesulfonate were significantly more effective than DMSA and BAL at mole ratios of 10:1. The relative effectiveness does not correlate with available data on stability constants. The toxicity of BAL itself becomes apparent at mole ratios of 20:1 and above.
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PMID:Comparison of standard chelating agents for acute mercuric chloride poisoning in mice. 736 52

Polychlorinated biphenyls (PCBs), cis-chlordane, oxychlordane, heptachlor epoxide, mirex, hexachlorobenzene (HCB), lindane, octachlorostyrene (OCS), p,p'-DDE,p,p'-DDT, dieldrin, triphenylphosphate (TPP), polybrominated biphenyls (PBBs), and polybrominated diphenyl ethers (PB-DPEs) were measured in the blubber, and five metals (mercury, lead, cadmium, chromium, and manganese) and selenium were measured in the liver of bottlenose dolphins (Tursiops truncatus) obtained from the Gulf of Mexico during an unusual mortality event in 1990. The collection of animals included fetuses, sucklings (< 1 year old), immature dolphins (2-5 years old), and adults of both sexes. PCBs, p,p'-DDE, HCB, and PBDPEs were detected in the blubber of each animal. Mean concentrations of organic contaminants were generally highest in adult males. p,p'-DDE was the single component analyte measured at the highest concentration. Immature females had greater concentrations of most chlorinated organics than adult females. Mercury and cadmium concentrations in liver increased with increasing age-class. The correlation between mercury and selenium in all animals was r = 0.96, with a mole ratio of 0.90. Concentrations of lead, manganese, cadmium, and chromium did not follow any particular age-class trend.
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PMID:Organochlorine, organobromine, metal, and selenium residues in bottlenose dolphins (Tursiops truncatus) collected during an unusual mortality event in the Gulf of Mexico, 1990. 775 3


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