Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0432222 (SEM)
 47,337 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Gas chromatographic methods using solvent extraction for the analysis of cyclopropane and and trichloroethene (trichloroethylene) are described and evaluated; cyclopropane was extracted into carbon tetrachloride and trichloroethene into carbon disulphide, using chloroform and toluene respectively as the internal standards. Ostwald solubility coefficients were measured for cyclopropane, halothane and trichloroethene in Krebs solution: at 310 K the respective values +/- SEM of the Ostwald coefficients are 0.181 +/- 0.009, 0.78 +/- 0.02 and 1.54 +/- 0.02; over the temperature range 295-310 K the respective temperature coefficients of solubility are -2.27, -4.18 and -3.81 in units of per cent/K at 310 K.
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PMID:Gas chromatographic determination of Ostwald solubility coefficients for cyclopropane, halothane and trichloroethene (trichloroethylene). 86 Nov 7

Experiments to investigate pressure-induced antagonism of the effects of general anaesthetics in isolated peripheral nerve from the frog are described. The doses of four gaseous general anaesthetic agents required to reduce electrically evoked action potentials by 50% (mean +/- SEM) were nitrous oxide 490 +/- 40.4 kPa, ethylene 665 +/- 212 kPa, dichlorodifluoromethane 108 +/- 17.2 kPa and cyclopropane 70 +/- 5 kPa. The combination of high pressure and the anaesthetic agent partially or completely restored the action potential amplitudes for the gaseous and some of the volatile agents (chloroform, diethyl ether, helothane). However, reversal of the effects of other volatile agents (ethanol, butanol), sodium pentobarbitone and two local anaesthetic agents (procaine, dibucaine) did not occur. The pressures used to effect a reversal were less than anticipated. This apparent inconsistency with the critical volume hypothesis for anaesthesia is discussed.
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PMID:Pressure antagonism of anaesthetic-induced conduction failure in frog peripheral nerve. 101 41

Amniotic fluid phospholipids were extracted and separated with chloroform: methanol (2:1 by vol). These phospholipids were also precipitated with cold acetone and the percentage of each phospholipid precipitated was calculated. The precipitation percentage of the six phospholipids studied ranged from 33.78 +/- 0.70 (mean +/- SEM) for lecithin to 93.77 +/- 1.40 for phosphatidylserine. The variation of L/S, PG/S and PI/S ratios depending on the precipitation step was also studied. We observed that cold acetone precipitation decreased L/S and PG/S ratios, whereas PI/S remained unchanged. Our results indicated that: (1) cold acetone precipitation affected each phospholipid in a different way; (2) the precipitation step was not an effective way of completely separating surfactant and non-surfactant material; (3) a new predictive value should be established if the L/S ratio without precipitation is to be used in the clinic on a daily basis.
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PMID:Amniotic fluid phospholipids. Study of the cold acetone precipitation effect. 273 76

A radioaerosol technique has been developed in order to assess deposition patterns from a new metered dose powder inhaler (Turbuhaler, Astra Pharmaceuticals). The radionuclide Tc99m dissolved in chloroform was added to a spheronised formulation of micronised terbutaline sulphate and the chloroform was allowed to evaporate. Turbuhaler subsequently delivered 0.5 mg of treated drug per metered dose. In vitro tests with a multistage liquid impinger showed that the fractionation of the drug dose between different particle size bands was similar to the fractionation of radioactivity. In a group of ten asthmatic patients, a mean 14.2% (SEM 2.1) of the drug dose was deposited in the lungs, with 71.6% (3.0) of the dose in the oropharynx. Of the remainder, 13.7% (2.1) was deposited on the mouthpiece, and 0.5% (0.2) recovered from exhaled air. The radiolabel was present in both central and peripheral zones of the lungs. All patients bronchodilated; forced expiratory volume in one second (FEV1) increased from 1.40 (0.24) l to 1.77 (0.24) l (p less than 0.01) 20 min after inhalation. These results suggest that both the distribution of drug and the clinical effect of terbutaline sulphate delivered from Turbuhaler are similar to those from a pressurised metered dose inhaler (MDI).
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PMID:Deposition and clinical efficacy of terbutaline sulphate from Turbuhaler, a new multi-dose powder inhaler. 273 2

Phosphoinositide content was measured in erythrocyte membranes from 11 patients with cystic fibrosis (CF) and from 12 control subjects to determine whether altered levels of phosphatidylinositol-4-phosphate (Ptdlns4P) or phosphatidylinositol-4,5-bisphosphate (Ptdlns(4,5)P2) are responsible for the decrease in Ca2+-adenosine triphosphatase (Ca2+-ATPase) activity in this disorder. Isolated membranes were extracted with an acidified chloroform-methanol solvent system. The recovered lipids were separated by one-dimensional thin-layer chromatography and quantified with a colorimetric assay for phosphorus. The results are expressed in molar percent, moles of phosphoinositide times 100 divided by the total number of moles of phospholipid per membrane. The means +/- SEM of Ptdlns(4,5)P2, Ptdlns4P, and phosphatidylinositol (Ptdlns) in CF membranes (1.07 +/- 0.18, 1.02 +/- 0.22, and 2.32 +/- 0.36 molar percent, respectively) were indistinguishable from controls (0.91 +/- 0.14, 0.85 +/- 0.12, and 2.21 +/- 0.32 molar percent, respectively) (P greater than 0.20 for all three pairs). The accuracy of quantitative recovery throughout the procedure was determined by adding a radioactive internal standard, L-3-phosphatidyl[2-3H]inositol to 10 membrane preparations. Although quantitative recoveries, as determined by percent radioactivity recovered, varied from 54% to 92%, mean Ptdlns(4,5)P2, Ptdlns4P, and Ptdlns levels appropriately corrected from tracer loss were still indistinguishable between the two groups. We conclude that absolute phosphoinositide levels are not altered in cystic fibrosis erythrocyte membranes and that the differences in Ca2+-ATPase activity cannot be explained on this basis.
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PMID:Phosphoinositide content of erythrocyte membranes in cystic fibrosis. 283 Mar 55

The technique of ultraplaning tissue consists of impregnating tissues with osmium tetroxide and thiocarbohydrazide (OTOTO), uranyl acetate and embedding in hard polyethylene glycol followed by planing a ultrasmooth surface with glass knives in an ultramicrotome. Subsequently, the tissue is stained with lead citrate, dehydrated, critical point dried and examined uncoated in an SEM. High resolution cut-surface and surface details are visible, permitting recognition of changes in surface contour and changes in intracellular organelles. An alternate procedure using celloidin-paraffin embedding consists of the following. OTOTO treated tissues are infiltrated with celloidin, hardened in chloroform, and infiltrated in paraffin. After the block is ultraplaned, the paraffin is removed with xylene. The tissues are hydrated and processed as with the polyethylene glycol procedure. This method has the advantage of holding fragile specimens together during the processing.
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PMID:The ultraplaning technique for SEM specimen preparation. 617 47

1,2-O-Isopropylidene-3-O-3'(N',N'-dimethylamino-n-propyl)-D -glucofuranose hydrochloride (I) is a new agent with claimed immunomodulatory action and antiviral activity. Thin-layer chromatographic procedures and identifying tests were developed to separate the drug, its synthetic precursors, and solvolytic products, and were applied to stability studies. It is stable in 0.1 N NaOH at 60 degrees where its acid solvolysis product, 3-O-3'-(N',N'-dimethylamino-n-propyl)-D-glucose is readily degraded. The partition coefficient of I (pK'a = 9.28) between chloroform and plasma was 6.4 +/- 0.2 SEM between pH 10.5 and 11.0. Plasma and urine (0.5 ml) adjusted to pH 11.0 were extracted with 10 ml of chloroform and the extract evaporated. The reconstituted residue in 50 microliters of benzene, with the disopropylaminoethyl analog of I as an internal standard, was derivatized with 50 microliters of heptafluorobutyric anhydride at 60 degrees for 45 min and was evaporated and reconstituted in 100 microliters of benzene to be assayed for I by GLC with electron capture detection with a sensitivity of 5 ng/0.5 ml of biological fluid. The procedure was applied to pharmacokinetics in the dog and a two-compartment body model was observed with a terminal half-life of 103-130 min. At the 40-mg dose, 60-64% was excreted renally unchanged and 20-34% as unidentified metabolites. At the 200-mg dose 82-85% was excreted unchanged and 15-17% as unidentified metabolites. The respective renal clearances of I were 135 and 163 ml/min. The respective total clearances of I were 204 and 191 ml/min. These metabolites were apparently unextracted with chloroform from biological fluids at pH 11 and the liquid scintillation counting (LSC) assay of extracted radiolabeled I appeared synonomous with the GLC assay of I in such fluids.
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PMID:Properties, stability, assay, and preliminary pharmacokinetics of the immunomodulatory 1,2-O-isopropylidene-3-O-3'(N',N'-dimethylamino-n-propyl)-D-glucofuranose hydrochloride. 708 43

The single isotopic-enzymatic assay of histamine was modified to increase its sensitivity and to facilitate measurement of plasma histamine levels. The modification involved extracting 3H-1-methylhistamine (generated by the enzyme N-methyltransferase acting on histamine in the presence of S-[methyl-3H]-adenosyl-L-methionine) into chloroform and isolating the 3H-1-methylhistamine by thin-layer chromatography (TLC). The TLC was developed in acetone:ammonium hydroxide (95:10), and the methylhistamine spot (Rf = 0.50) was identified with an o-phthalaldehyde spray, scraped from the plate, and assayed in a scintillation counter. The assay in plasma demonstrated a linear relationship from 200 to 5000 pg histamine/ml. Plasma always had higher readings than buffer, and dialysis of plasma returned these values to the same level as buffer, suggesting that the baseline elevations might be attributable to histamine. However, all histamine standard curves were run in dialyzed plasma to negate any additional influences plasma might exert on the assay. The arithmetic mean (+/- SEM) in normal plasma histamine was 318.4 +/- 25 pg/ml (n = 51), and the geometric mean was 280 +/- 35 pg/ml. Plasma histamine was significantly elevated by infusion of histamine at 0.05 to 1.0 micrograms/kg/min or by cold immersion of the hand of a cold-urticaria patient. Therefore this modified isotopic-enzymatic assay of histamine is extremely sensitive, capable of measuring fluctuations in plasma histamine levels within the normal range, and potentially useful in analysis of the role histamine plays in human physiology.
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PMID:Measurement of plasma histamine: description of an improved method and normal values. 709 24

We evaluated the ability of alpha-phenyl-tert-butyl nitrone (PBN) to trap free radicals and to protect the rat myocardium during ischemia and reperfusion. Isolated bicarbonate buffer-perfused hearts (n = 8) were subjected to 20 min global ischemia (37 degrees C) followed by reperfusion with 0.4 to 4.0 mM PBN. Coronary effluent containing the PBN adduct was extracted in toluene. Electron spin resonance analysis of the toluene extract revealed a PBN-hydroxyl adduct. To verify this assignment, a Fenton system was used to generate an authentic PBN-hydroxyl adduct (n = 8), which yielded the same ESR spectra as the reperfusion-derived adduct. The structure of the adduct formed in the Fenton system was confirmed by gas chromatography-mass spectrometry. The ESR parameters of the PBN-hydroxyl adduct were exquisitely sensitive to solvent polarity during extraction of the adduct. Extraction of an authentic PBN-hydroxyl adduct into chloroform, chloroform:methanol, and toluene closely matched the ESR parameters obtained during reperfusion of ischemic myocardium in other animal models. To determine whether PBN could confer any protective effect during ischemia or reperfusion, hearts (n = 8/group) were subjected to 35 min global ischemia at 37 degrees C with the St. Thomas' II cardioplegic solution followed by 30 min reperfusion. Percent recovery (mean +/- SEM) of developed pressure, rate pressure product, and leakage of lactate dehydrogenase during reperfusion in control hearts were 58 +/- 3%, 48 +/- 4% and 3.2 +/- 0.5 IU/15 min/g wet wt. PBN at a concentration of 0.4 mM or 4.0 mM when present either during ischemia alone or reperfusion alone did not exert any effect upon recovery of developed pressure, rate pressure product or post-ischemic enzyme leakage. We conclude that PBN fails to improve contractile recovery and reduce enzyme leakage during reperfusion of myocardium subjected to global ischemia.
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PMID:Lack of protection of PBN in isolated heart during ischemia and reperfusion: implications for radical scavenging mechanism. 801 39

Tunicates have been reported to be a rich source of biologically active compounds. In this study, we demonstrate the presence of cytotoxic substances in Phallusia nigra, a common tunicate from Brazilian coastal waters. An extract of tunicate tissue was obtained by homogenizing the visceral organs from 50 specimens in methanol, followed by filtration and concentration in a rotary vacuum evaporator. Finally, the concentrate was partitioned with chloroform to remove lipids. The resulting extract possessed antimitotic and hemolytic activity. The former was demonstrated as a delay in the development of sea urchin eggs by partially inhibiting the process of cleavage (first cleavage, EC50 +/- SEM = 3.44 +/- 0.84 mg/ml). The < 500 molecular fraction of the extract obtained by ultrafiltration also inhibited cell proliferation (the number of viable cells was decreased by 68% with 500 micrograms/ml) and DNA synthesis of T47D cells derived from human breast carcinoma as measured by [3H]-thymidine incorporation (66% of the control value after 24-h incubation with 100 micrograms/ml). Dose-dependent hemolysis obtained with P. nigra extract on mouse erythrocytes had an EC50 +/- SEM = 1.12 +/- 0.02 mg/ml for a 0.5% erythrocyte suspension. Hemolysis could be reduced by pre-incubating the cells with choline-containing phospholipid. Sphingomyelin (40 micrograms/ml) increased the EC50 by two-fold to 2.86 +/- 0.04 mg/ml, but phosphatidylcholine (80 micrograms/ml) did not modify hemolysis.
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PMID:Cytotoxic activity of a methanol extract of Phallusia nigra (Tunicata, Ascidiacea). 873 32


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