Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: C35E7 .10
 63,145 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

16 alpha-hydroxyandrost-4-ene-3,17-dione (16 alpha OH-A) was measured in pregnant women by radioimmunoassay (RIA) with specific antiserum. After extraction of the serum the 16 alpha OH-A fraction was separated by the use of Sephadex LH-20 mini column. Lately, high performance liquid chromatograph (HPLC) was combined with RIA (HPLC-RIA) for the measurement of various kinds of steroids from an extract of a serum or urine sample. The purpose of this study was to establish the HPLC-RIA method for the measurement of 16 alpha OH-A in pregnant women. Pooled serum was extracted twice with 5 volumes of ethylether, and the combined extract was separated either by LH-20 mini column with the solvent system n-hexane:benzene:methanol = 8:1:1 or by HPLC ODS column with MeOH:CH3CN:H2O = 60:10:30. The 16 alpha OH-A fraction was collected and an aliquot was measured by RIA. The coefficients of variance for intra and inter-assay (n = 10) were computed to be 8.6 and 12.1% with LH-20, and 7.2 and 11.7% with HPLC, respectively. Recovery rate was 95.7 +/- 7.4% with LH-20 and 92.5 +/- 8.7% with HPLC. The values of 16 alpha OH-A as measured following two kinds of chromatographies were closely related to each other. The mean serum hormone concentrations +/- standard errors were as follows. In maternal peripheral blood up to 11 weeks 1.04 +/- 0.19 (LH-20) and 0.55 +/- 0.10 (HPLC), 12 to 23 weeks 1.22 +/- 0.23 (LH-20) and 0.67 +/- 0.77 (HPLC), 24 to 36 weeks 2.24 +/- 0.42 (LH-20) and 2.27 +/- 0.28 (HPLC), above 37 weeks 1.64 +/- 0.52 (LH-20) and 1.85 +/- 0.34 (HPLC), second stage of labor 5.07 +/- 1.28 (LH-20) and 4.73 +/- 0.54 (HPLC) ng/ml of steroid, respectively, were measured. Steroid concentration in umbilical arterial and venous blood were 7.87 +/- 1.41 (LH-20), 3.75 +/- 0.83 (HPLC) and 8.69 +/- 1.66 (LH-20), 5.38 +/- 0.87 (HPLC) ng/ml, respectively. The values of 16 alpha OH-A levels tended to increase as gestation proceeded. These data suggest production of 16 alpha OH-A by the feto-placental unit. An elevated level of 16 alpha OH-A is found in the umbilical venous blood as compared to the arterial samples. This indicates an extensive conversion. After onset of labor, the 16 alpha OH-A levels were significantly increased because of precursor steroid 16 alpha-hydroxydehydroepiandrosterone-sulfate is mobilized by the stress of labor.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:[Studies on 16 alpha-hydroxyandrost-4-ene-3, 17-dione in human pregnancy measured by high performance liquid chromatography and radioimmunoassay]. 409 86

The rates of hydrolysis of N-[(alpha-L-rhamnopyranosyloxy)phospho]-L-leucyl-L-tryptophan (phosphoramidon), N alpha-phosphoryl-L-leucyl-L-tryptophan (PO3LeuTrp), N alpha-phosphoryl-L-leucyl-L-phenylalanine (PO3LeuPhe), and N alpha-phosphoryl-L-leucyl-L-phenylalaninamide (PO3LeuPheNH2) were followed by proton nuclear magnetic resonance spectroscopy. The rates of hydrolysis (kobsd) of PO3LeuTrp, PO3LeuPhe, and PO3LeuPheNH2 were all first order in phosphorylamide concentration over the pH range studied (3.8-9.5). The values for kobsd at pH 7.3 and 37 degrees C are as follows: PO3LeuTrp, 0.35 h-1; PO3LeuPhe, 0.63 h-1; PO3LeuPheNH2, 0.73 h-1. The values for kobsd do not significantly change between pH 5 and pH 8 but dramatically decreased with increasing pH. The hydrolysis of PO3LeuPhe and PO3LeuPheNH2 above a pH of approximately 5 was positively correlated with the concentration of monoanionic species (NHRPO3H)1-, and the values for the first-order rate constants for the respective monoanionic species were calculated to be 0.66 +/- 0.03 h-1 and 1.07 +/- 0.10 h-1. Phosphoramidon was not found to hydrolyze after 6 days at 37 degrees C at a pH of 4.6 and 7.7, while the phosphorylamide PO3LeuTrp, synthesized by the removal of L-rhamnose from phosphoramidon by base hydrolysis, was found to rapidly hydrolyze under these conditions. Solvolysis in aqueous methanol of PO3LeuPhe and PO3LeuPheNH2 indicates that the hydrolysis reaction is bimolecular, proceeding by way of direct attack of solvent (H2O, CH3OH) on phosphorus.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Inhibition of the elastase of Pseudomonas aeruginosa by N alpha-phosphoryl dipeptides and kinetics of spontaneous hydrolysis of the inhibitors. 643 34

We have adapted to erythrocytes a method for the determination of alpha- and gamma-tocopherols in plasma and platelets. Erythrocytes (50 microL) were extracted with methanol containing tocol (internal standard) and pyrogallol. Tocopherols were partitioned into chloroform, washed, and injected in methanol onto a reversed-phase (C18) "high-performance" liquid-chromatographic column. The mobile phase was methanol/water (99/1 by vol) at a flow rate of 2 mL/min and detection was with a "high-performance" spectrophotofluorometer. The limit of detection for either tocopherol is 0.10 microgram/mL of packed cells. Analytical recoveries ranged from 93 to 104%. Some values for tocopherols in human erythrocytes are presented.
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PMID:Liquid-chromatographic determination of alpha- and gamma-tocopherols in erythrocytes, with fluorescence detection. 661 36

The ideal electrode for stimulation of the nervous system is one that will inject charge by purely capacitive processes. One approach is to exploit the type of metal-oxide combination used in electrolytic capacitors, e.g., Ta/Ta2O5. For this purpose, fine tantalum wire (0.25 mm diam) was etched electrolytically at constant current in a methanol solution of NH4Br containing 1.5 wt % H2O. Electrolytic etching produced a conical tip with a length of ca. 0.5 mm and shaft diameters ranging from 0.10 to 0.16 mm. The etched electrodes were anodized to 10 V (vs. SCE) in 0.1 vol % H3PO4. The capacitance values normalized to geometric area of etched electrodes ranged from 0.13 to 0.33 micro F mm-2. Comparison of these values to the capacitance of "smooth" tantalum anodized to 10 V (0.011 micro F mm-2) indicated that the degree of surface enhancement, or etch ratio, was 12-30. The surface roughness was confirmed by scanning electron microscopy studies which revealed an intricate array of irregularly shaped surface projections about 1-2 micrometers wide. The etched electrodes were capable of delivering 0.06-0.1 micro C of charge with 0.1 ms pulses at a pulse repetition rate of 400 Hz when operated at 50% of the anodization voltage. This quantity of charge corresponded to volumetric charge densities of 20-30 micro C mm-3 and area charge densities of 0.55-0.88 micro C mm-2. Charge storage was proportionately higher at higher fractional values of the formation voltage. Leakage currents at 5 V were ca. 2 nA. Neither long-term passive storage (1500 h) nor extended pulsing time (18 h) had a deleterious effect on electrode performance. The trend in electrical stimulation work is toward smaller electrodes. The procedures developed in this study should be particularly well-suited to the fabrication of even smaller electrodes because of the favorable electrical and geometric characteristics of the etched surface.
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PMID:Preparation of etched tantalum semimicro capacitor stimulation electrodes. 684 72

Blood methanol concentrations were measured in 24 1-year-old infants administered aspartame, a dipeptide methyl ester sweetener. The doses studied included a dose projected to be the 99th percentile of daily ingestion for adults (34 mg/kg body weight), a very high use dose (50 mg/kg body weight) and a dose considered to be in the abuse range (100 mg/kg body weight). Blood methanol values in infants were compared to values observed previously in adults administered equivalent doses of aspartame. Methanol concentrations were below the level of detection (0.35 mg/dl) in the blood of 10 infants administered aspartame at 34 mg/kg body weight, but were significantly elevated (P less than or equal to 0.05) after ingestion of aspartame at 50 and 100 mg/kg body weight. At the latter doses, mean peak blood methanol concentrations and the area under the blood methanol concentration-time curve increased in proportion to dose. Mean (+/- SEM) peak blood methanol concentration was 0.30 +/- 0.10 mg/100 ml at a 50 mg/kg body weight aspartame dose (n = 6) and 1.02 +/- 0.28 mg/ml at the 100 mg/kg body weight dose (n = 8). Blood methanol values in infants were similar to those observed in normal adults.
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PMID:Blood methanol concentrations in one-year-old infants administered graded doses of aspartame. 2773 36

A high-pressure liquid chromatographic method is presented for the determination of ibuprofen in human plasma. Ibuprofen is extracted from plasma acidified with 1.0 M phosphoric acid using hexane containing p-phenylphenol as an internal standard. A reversed-phase octadecylsilane column was used with a liquid phase of 65% methanol and 35% 0.10 M acetate buffer (pH 5.0). A spectrofluorometric detector with an excitation wavelength of 253 nm and a band pass filter (230--420 nm) provided a detectable peak for 1 microgram of ibuprofen/ml of plasma. The effect of the pH and molarity of the mobile phase on the capacity factor was studied.
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PMID:High-pressure liquid chromatographic determination of ibuprofen in plasma. 697 45

An isocratic high-pressure liquid chromatographic method for the determination of naproxen and its desmethyl metabolite in human plasma is presented. A reversed-phase octadecylsilane column was utilized with a mobile phase consisting of 55% methanol and 45% 0.10 M acetate buffer, pH 5.0. A spectrofluorometric detector with an excitation wavelength of 253 nm and a band pass filter provided high sensitivity with no interference from normal plasma constituents. The reproducibility and precision of the method were shown by analysis of spiked samples containing 2.5-70 micrograms/ml of plasma.
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PMID:An isocratic high-pressure liquid chromatographic determination of naproxen and desmethylnaproxen in human plasma. 708 53

The antibiotic activity and some of the physicochemical properties of the pigment produced by P. cepacia 4137 were studied. The pigment was isolated from the medium with chloroform. Preparative chromatography on columns with silica gel and thin-layer chromatography on Silufol plates revealed red-orange and straw-yellow fractions in the composition of the antibiotic. The latter fraction showed a significant antimicrobial activity against gram-positive and gram-negative bacteria, fungi and yeasts. The red fraction was inferior to the yellow one with respect to its antimicrobial activity. Both substances could be stained with a butanol solution of FeCl3. The absorption maxima of their methanol solutions were observed at 225, 325 and 455 nm with respect to the red fraction and at 220, 330 and 405 with respect to the yellow fraction. The elemental analysis of a more highly purified red fraction showed the following: C 54.10, H 6.85, N 7.93 and O 31.12. It is suggested that the substances are derivatives of hydroxyphenazine carboxylic acids.
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PMID:[Antibiotic properties of Pseudomonas cepacia]. 712 16

An assay for glycine and taurine conjugates of cholic, chenodeoxycholic and deoxycholic acid in serum by a high pressure liquid chromatographic-enzymatic system is presented. The bile acids are extracted from serum by a reverse-phase liquid chromatographic process with an octadecylsilane column. The bile acid conjugates are separated on a muBondapak C18 column with methanol/KH2PO4 buffer, 20 mmol/l, pH 5.3 as a mobile phase in less than 30 min at a flow rate of 1.4 ml/min. The bile acid fractions are measured by enzymatic fluorometry using a 3 alpha-hydroxysteroid dehydrogenase-diaphorase system. Recoveries ranged from 82 to 96%, coefficients of variation were from 5 to 15%, and detection limits were from 0.03 to 0.08 mumol/l. Mean serum concentrations ranged from 0.10 to 0.39 mumol/l in the fasting state and from 0.29 to 1.55 mumol/l postprandially in subjects with normal liver function.
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PMID:A high-pressure liquid chromatographic-enzymatic assay for glycine and taurine conjugates of cholic, chenodeoxycholic and deoxycholic acid in serum. 715 57

Formic acid does not accumulate in the rat after the administration of methanol as it does in methanol-poisoned humans and monkeys. In addition, rats do not manifest the metabolic acidosis and ocular toxicity characteristic of methanol intoxication in primates. Nitrous oxide treatment was used to inhibit 5-methyltetrahydrofolate homocysteine methyltransferase (methionine synthetase, EC 4.2.99.10) in order to delineate the role of this enzyme in regulating the metabolism of formate in rats and in determining the sensitivity of this species to methanol intoxication. Nitrous oxide treatment resulted in a decrease in hepatic levels of nonmethylated tetrahydrofolate forms and an increase in 5-methyltetrahydrofolate. Rats treated with nitrous oxide exhibited a marked decrease in the rate of oxidation of formate to carbon dioxide. The rate of disappearance of formate from the blood in these animals was decreased to half the control rate. Rats treated with nitrous oxide and administered methanol accumulated formate in blood and developed metabolic acidosis. These studies support the concept of a key role of methionine synthetase in supplying the tetrahydrofolate required for the folate-dependent oxidation of formate to carbon dioxide as well as the importance of this pathway in determining the sensitivity of a species to methanol poisoning.
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PMID:Methanol poisoning and formate oxidation in nitrous oxide-treated rats. 720 59


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