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PubMedDate not supplied

Extraction of acidic drugs from water and plasma: study of recovery with five different solvents.

The recovery of 28 acidic drugs from water and plasma was investigated spectrophotometrically using five different solvents for extraction: hexane, diethyl ether, toluene, n-butyl chloride, and chloroform. Nine barbiturates, three sulfonamides, four diuretics, and twelve other acidic drugs were studied. As classes, the barbiturates, the sulfonamides, and the diuretics were optimally extracted with diethyl ether from both water and plasma, while considerable variation in recovery was noted among solvents for the other drugs. In general, recoveries from water were higher than those from plasma with most solvents, except for the sulfonamides for which recoveries were often better from plasma. Extraction recoveries for the individual drugs are tabulated and compared.

Barbiturates↗
PubMed1977

Pulmonary hemodynamics during induction of anesthesia.

Changes in pulmonary hemodynamics and acid-base balance were recorded during induction of anesthesia using either intravenous administration of barbiturate (28 patients) or inhalation of N2O-O2-halothane (12 patients). The two types of induction resulted in equal elevations of pressures within the pulmonary circulation. The increase, proportional on the two sides of the heart, was most pronounced immediately before endotracheal intubation. Cardiac index decreased before and during intubation but subsequently increased to levels above control values. Systemic blood pressure increased more during barbiturate than during inhalation induction. Changes in acid-base balance were similar during the two types of induction: arterial blood PCO2 and PO2 increased, pH decreased, and standard bicarbonate remained unchanged. Changes in pulmonary arterial mean pressure and central venous pressure were correlated with changes in PACO2. Pulmonary capillary filtration pressure (i.e., pulmonary capillary wedge pressure minus plasma colloid osmotic pressure) was negative in every patient before anesthesia. During induction of anesthesia, filtration presures became positive in half the patients. Observed changes in circulation may have been caused by hypercapnia alone or by a combination of hypercapnia and vescular reflexes associated with instrumentation during intubation. The increased strain on the heart during induction of anesthesia may lead to cardiac failure in patients with diminished cardiac reserve.

Anesthesia, General↗
PubMed1986

Release of gamma-aminobutyric acid from the visual cortex of young kittens.

Barbiturate-anaesthetized kittens of less than one month of age were used for the quantitative determination of the in vivo release of endogenous gamma-aminobutyric acid (GABA) from visual cortex by two methods: push-pull perfusion and cortical cup superfusion. Analysis by high-performance liquid chromatography (HPLC) demonstrated that marked elevations of GABA were elicited during electrical stimulation of cortex (inside the cup or adjacent to the cannulae) and were released into the artificial extracellular fluid perfused within the collecting cup or through the cannulae. The results provide additional support for the view that GABA-mediated neuronal inhibition in early ontogenetic stages of visual cortex is widespread and robust.

Aging↗
PubMed1982

Studies on the Ritter reaction. I. Synthesis of 3-/5-barbituryl/-propanesulfonic acids with anti-inflammatory activity.

Under the condition of the Ritter reaction the allyl group bound to C5 of the barbituric ring was observed to transform, due to addition of sulfuric acid, into beta-sulfooxy-propane-sulfonic or beta-hydroxy-propanesulfonic group. Inner anhydrides of the structure of beta-sulfone or carbyl sulfate are the intermediate products of these reactions. Well water-soluble calcium salts of the synthetized acids were pharmacologically analyzed.

Acetonitriles↗
PubMed1997

Mechanisms of the selective cytotoxic actions of certain essential fatty acids.

Polyunsaturated fatty acids (PUFA) have a selective cytotoxic/cytostatic effect on a number of tumor cell lines in culture. Although this process may be enhanced by the addition of iron there is a minimum level of PUFA necessary for potentiation of cell death. Vitamin E blocks PUFA cytotoxicity when added up to 5 days after fatty acid administration. Levels of thio-barbiturate reactive material (TBARM) in the medium rise in parallel with cell death. However, they are not affected by small alterations in temperature or oxygen tension. Incubating cells with PUFA causes marked alterations in the fatty acid patterns of both neutral and phospholipid fractions. Membrane fluidity is increased and the activity of membrane-bound receptors may be influenced directly or through the actions of eicosanoids derived from the exogenous fatty acid. PUFA may be an effective way of influencing tumor growth and a safe approach for the management of human cancer.

Animals↗
PubMed1965

Interference with valine and isoleucine biosynthesis by cyclic hydroxamic acids.

Hogg, Robert W. (University of Illinois, Urbana), Chitra S. Biswas, and Harry P. Broquist. Interference with valine and isoleucine biosynthesis by cyclic hydroxamic acids. J. Bacteriol. 90:1265-1270. 1965.-The introduction of a hydroxyl group in a number of common barbiturates, a substitution which converts these compounds to cyclic hydroxamic acids, gives rise to compounds which inhibit growth of Escherichia coli. The toxicity of these hydroxybarbiturates appears to be associated, at least in part, with interference with valine and isoleucine biosynthesis, as a combination of these amino acids counteracts their toxicity. A subinhibitory level of 1-hydroxy-5-ethyl-5-isopropylbarbituric acid (hydroxyipral) was counteracted either by valine or by its early precursor, alpha-acetolactate, and led to a study of the effect of these cyclic hydroxamic acids on acetolactate synthesis in a cell-free enzyme system of E. coli. In this system, the parent barbiturates and their respective hydroxy derivatives were only moderately active in blocking acetolactate synthesis. Detailed kinetic studies of the most active compound, hydroxyipral showed no obvious relationship to the substrate or cofactors of the system. The inhibitory effects of hydroxyipral, either on growth of E. coli or in the acetolactate-forming system, could not be counteracted by Fe(++), but the toxic effect of aspergillic acid and o-phenanthroline in these instances was reversed by Fe(++), which implies an iron involvement in the acetolactate-forming system of E. coli.

Barbiturates↗
PubMed1976

Metabolism of 5-(p-toluyl)-5-ethylbarbituric acid and 5-(p-toluyl)-5-phenylhydantoin in the isolated perfused rat liver.

The primary route of metabolism of 5-(p-toluyl)-5-ethylbarbituric acid (TEBA) and 5-(p-toluyl)-5-phenylhydantoin (MPPH) in the isolated perfused rat liver is oxidation of the aromatic methyl group either to a primary alcohol which is then conjugated with glucuronic acid and excreted in the bile (MPPH only) or to the carboxylic acid which is excreted free in the bile (both TEBA and MPPH). All metabolites were identified by previously described permethylation and GC-MS techniques.

Animals↗