Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0847097 (acidity)
 15,165 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Serum creatine phosphokinase (CPK) concentrations were determined in healthy volunteers for the first 48 hours after intramuscular injection of 50 mg chlordiazepoxide hydrochloride or of its solvent alone. Intramuscular injection of both the drug solution and its solvent was painful and caused CPK elevations. The CPK rise due to the drug solution was 33 per cent higher than that due to the solvent alone, but the difference was not significant. The pH of the solvent preparation is low and it contains high concentrations of propylene glycol. The pain and muscle damage due to injection of the solvent could be due to its acidity and its high osmolarity. Problems associated with intramuscular injections of water-insoluble drugs are not resolved by the use of such solvent preparations.
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PMID:Serum creatine phosphokinase concentrations after intramuscular chlordiazepoxide and its solvent. 94 24

The effects of parenteral pilocarpine, atropine, and norepinephrine on salt and water transport were studied in jejunum and ileum of anesthetized rats. Pilocarpine increased jejunal transmural PD, reduced absorption of Na, K, HCO3, and H2O, and increased secretion of Cl; in ileum, it caused secretion of Na and H2O, elicited secretion of K, and reduced the absorption of Cl. In both segments, perfusate became more akaline, and there was less of a rise in PCO2. Atropine prevented all changes caused by pilocarpine. Atropine alone increased jejunal absorption of Na and HCO3 and acidity of perfusate, implying that cholinergic nerves influence transport. Norepinephrine augmented jejunal absorption of Na, Cl, and H2O but caused no change in PD. In ileum, norepinephrine increased absorption of Na and Cl, reduced the rise in pH, increased the rise in PCO2 of perfusate, but did not affect net HCO3 movement. With all agents, when Na absorption increased, perfusate became more acidic in jejunum and less alkaline in ileum, evidence of an association between Na and H transport.
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PMID:Intestinal ion transport: effect of norepinephrine, pilocarpine, and atropine. 96 67

The rate constant for the catalytic transfer of the active-site PO3 group from rabbit muscle phosphoglucomutase to the hydroxyl group of a water molecule is about 3 x 10(-8) s-1 under optimal reaction conditions, but in the absence of the normal substrate, viz., at pH 7.5 and 30 degrees C, in the presence of saturating Mg2+; the corresponding constant for transfer to the 6-hydroxyl group of glucose 1-phosphate under analogous conditions, about 1000 s-1, is larger than this by some 3 x 10(10)-fold. Since no single factor appears to be capable of providing a rationale for a majority of this "substrate-induced rate effect" (Ray, jr., W.J., and Long, J.W. (1976), Biochemistry, the preceding paper in this issue), the change in the PO3-transfer rate produced by binding various parts of the phosphoglucosyl moiety to the enzyme, both separately and concurrently, was investigated. The rate of PO3 transfer to water is increased by up to 1000-fold by binding entities that provide the active site with a second PO3 group, e.g., ethyl phosphate or inorganic phosphite. Using an alcoholic acceptor further increases transfer efficiency (in the presence of bound phosphite): increase with methanol, about 2000-fold on a molar basis. The reactivities of ten other primary aliphatic alcohols vary by nearly 600-fold as the acidity of the PO3 acceptor is varied over a 4000-fold range. Although no straightforward relationship is observed between the efficiency of an alcohol as an acceptor and its acidity - presumably because of complications due to steric effects, for example - an increased transfer rate of 100-fold, relative to the water reaction, is estimated for a simple primary alcohol with a pKa similar to that expected for the 6-hydroxyl group of glucose 1-phosphate, when the alcohol is present at a concentration of 1 M. Joining an alcoholic acceptor and a PO3 group via five apparently inert bridging units changes PO3 transfer to an intramolecular process; in the case of 1,4-butanediol monophosphate the rate of transfer also increases by 240-fold, relative to the analogous reaction in the presence of 1 M propanol and bound inorganic phosphite. Comparable values also are obtained in comparisons of PO3 transfer rates for trans- 1,4-butenediol and 1,4-butynediol monophosphates relative to 1 M allyl and propargyl alcohols, respectively, in the presence of bound phosphite. An increased rate of transfer also is produced by binding the xylosyl part of the glucose ring, either when the acceptor is an hydroxyl group attached to the ring or when it is the hydroxyl group of a water molecule, e.g., as in the water reaction facilitated by bound xylose 1-phosphate. These and other results suggest that most of the differences between the rates of the water reaction and the glucose 1-phosphate reaction can be rationalized in terms of four fairly discrete factors whose approximate values are as follows: the PO4 factor, 1000-fold; the C-OH/H-OH factor, 100-fold; the nucleophile-binding factor, 250-fold; and the (CHOH)3-bridging factor, 200-fold...
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PMID:An analysis of the substrate-induced rate effect in the phosphoglucomutase system. 96 19

The objectives of this study were to assess the clinical efficacy of a new oral ranitidine liquid preparation in reducing gastric acidity and volume, to determine the degree of absorption of the drug, and to determine the duration of drug effect. Eighty preoperative children between the ages of one and six years were enrolled in each of three centres. Each subject was allocated to one of the following groups: Group A - apple juice, 5 ml.kg-1 plus placebo liquid; Group B - apple juice, 5 ml.kg-1 plus ranitidine hydrochloride 2 mg.kg-1; Group C - water, 5 ml and placebo liquid; or Group D - water, 5 ml and ranitidine liquid 2 mg.kg-1. All study agents were administered at least two hours before surgery along with a dye marker, sulfobromophthalein 1 ml (50 mg.ml-1). Following induction of anaesthesia, gastric fluid was aspirated, and analyzed for pH, volume, and sulfobromophthalein content (as an index of the ingested fluids). A serum sample was also drawn and analyzed for ranitidine content by high performance liquid chromatography. Groups B and D had fewer subjects with pH below 2.5 and gastric volume > 0.4 ml.kg-1. The duration of reduced volume and acidity was shown to be greatest from two to four hours after drug administration. Thirty-three percent of subjects receiving oral ranitidine, 2 mg.kg-1 hydrochloride as a single dose demonstrated no measurable effect on gastric pH and volume; 28 of those subjects had adequate ranitidine serum levels.
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PMID:Efficacy, duration, and absorption of a paediatric oral liquid preparation of ranitidine hydrochloride. 128 4

The gastrointestinal (GI) physiology of beagle dogs was regulated with a combined-treatment of intramuscular pentagastrin (10 micrograms/kg x 2) and intravenous atropine sulfate (0.02 mg/kg x 1). Here, the gastric acidity, the gastric emptying time and the small intestinal transit time in the regulated-dogs were respectively around pH 2, 0.7h and 4h, approximating those in healthy humans. The superiority of the regulated-dogs over the intact dogs was confirmed in comparative bioavailability studies by using two classes of commercial preparations. Both the conventional tablet and the sustained-release capsule of diclofenac sodium exhibited simple and similar average plasma concentration-time curves of free diclofenac in the intact dogs, while the latter preparation is reported to reveal a bimodal plasma curve of the drug in healthy humans. The regulated-dogs, however, permitted a bimodal average plasma pattern of the drug for the capsules due to an approximation of the GI physiology between humans and these classes of the dogs. The combined-treatment of beagle dogs with pentagastrin and atropine sulfate seems to supply a useful animal model in predicting the absorption characteristics of the sustained-release preparations and poor water-soluble drugs.
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PMID:Bioavailability study of commercial sustained-release preparations of diclofenac sodium in gastrointestinal physiology regulated-dogs. 129 33

The effects of fasting and of histamine (H2) antagonists on gastric volume and acidity were studied in 56 baboons undergoing various surgical procedures under general anesthesia and randomly allocated into 4 groups; group A--fasted for 14 hours; group B--given 100-120 ml of water 3 hours before surgery; groups C and D--also given 100-120 ml of water 3 hours before surgery; in addition, the former received cimetidine 10 mg/kg IM and the latter ranitidine 1.5 mg/kg IM 30-40 minutes before anesthesia. There were no significant differences between groups A and B with respect to the gastric volume and pH. Both ranitidine and cimetidine significantly (P < 0.02) reduced gastric volume and increased gastric pH. Thus, prolonged withholding of oral fluids does not reduce the gastric volume or increase gastric pH. H2-antagonists are effective in reducing both gastric residual volume and pH.
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PMID:Is preoperative fasting necessary? 130 51

Changes in the oxidation state of the DNA bases, induced by oxidation (ionization) or by reduction (electron capture), have drastic effects on the acidity or basicity, respectively, of the molecules. Since in DNA every base is connected to its complementary base in the other strand, any change of the electric charge status of a base in one DNA strand that accompanies its oxidation or reduction may affect also the other strand via proton transfer across the hydrogen bonds in the base pairs. The free energies for electron transfer to or from a base can be drastically altered by the proton transfer processes that accompany the electron transfer reactions. Electron-transfer (ET) induced proton transfer sensitizes the base opposite to the ET-damaged base to redox damage, i.e., damage produced by separation of charge (ionization) has an increased change of being trapped in a base pair. Of the two types of base pair in DNA, A-T and C-G, the latter is more sensitive to both oxidative and reductive processes than the former. Proton transfer induced by ET does not only occur between the heteroatoms (O and N) of the base pairs (intra-pair proton transfer), but also to and from adjacent water molecules in the hydration shell of DNA (extra-pair proton transfer). These proton transfers can involve carbon and as such are likely to be irreversible. It is the A-T pair which appears to be particularly prone to such irreversible reactions.
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PMID:Electron-transfer-induced acidity/basicity and reactivity changes of purine and pyrimidine bases. Consequences of redox processes for DNA base pairs. 132 99

1. Toads fed meal worms retained water, amounting to about the mass of the meal. 2. Secretion of gastric juice in the initial phase of digestion of a large meal would deplete the extracellular fluid of about half of the chloride ions. 3. Ingestion and rapid digestion of large meals in toads and other carnivorous vertebrates imply tolerance of large variations in anion composition and acidity of the extracellular fluid.
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PMID:Relationships between feeding, digestion and water balance in a carnivorous vertebrate, the toad Bufo bufo L. 134 24

Many different compounds can be produced by using microorganisms or enzymes. An important element in the design of a viable biotechnological process is the selection of an economical and efficient separations train. Production of chemicals via biotechnology generally requires isolation and purification from dilute, aqueous solution. A general framework for separation process design relies on exploiting a unique molecular physicochemical property (or properties) for separating the molecule of interest from water and the other species in solution. Important properties that can be utilized for the recovery of low molecular weight polar compounds are molecular charge, hydrophobicity, Lewis acidity or basicity, volatility, and limited solubility. In turn, it can be useful to characterize molecular properties by using separation processes, such as, for example, hydrophobicity by measuring octanol/water partition coefficients. This paper reviews the use of adsorption onto hydrophobic, nonpolar macroreticular polymers and Lewis acid-base complexation by using functionalized polymers for the recovery of amino acids, carboxylic acids, alcohols, and ketones from dilute aqueous solution. The focus will be on utilizing physical and chemical properties to predict uptake capacity. This information will be relevant to separation process development and will help to characterize molecular properties in aqueous solution.
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PMID:Strategies for the recovery of chemicals from fermentation: a review of the use of polymeric adsorbents. 136 80

A micellar electrokinetic capillary chromatographic method has been developed for the qualitative assay of amoxycillin and its degradation products and clavulanic acid. Together with amoxycillin the latter acid is an important constituent in the antibiotic Augmentin. The analytical procedure is fast and analytes can be identified both from their migration times and from changes in migration time observed either at different pH values or in electropherograms run in H2O and D2O based buffers of the same acidity.
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PMID:Micellar electrokinetic capillary chromatography of amoxycillin and related molecules. 144 40


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