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Query: UMLS:C0847097 (acidity)
 15,165 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Growth and hydrolytic action on tannins of 6 strains of yeasts (isolated from tanning liquors and xylophagous insects) are studied in culture media containing various concentrations of tannic acid. The influence of medium acidity is also considered. According to the strains, growth is more or less restrained and hydrolytic activity is variable. Except for gallotannins, hydrolysable tannins are not hydrolysed.
Mycopathologia 1975 Dec 31
PMID:[Interaction of yeasts with tannins. II. Study of various yeasts hydrolysing tannic acid in tannin culture media]. 0 72

The intact heart of a young rat was excised rapidly and cooled to 0 degree C; its energy-rich compounds were examined by 31P Fourier Transform nuclear magnetic resonance. The heart showed the characteristic spectrum of sugar phosphates, inorganic phosphate, phosphocreatine, and magniesium phates, inorganic phosphate, phosphocreatine, and magnesium ATP, characteristics of the energizing state of the nonbeating tissue. Warming to 30 degrees C imposes an energy load upon the heart consistent with short-term resumption of beating, concomitant intracellular acidosis, and decomposition of all detectable energy-rich compounds. The intracellular acidity causes a shift from pH 7.0 to 6.0. The effects of possible interferences with this pH measurement are considered. The method appears to have wide usefulness in cardiac infarct models for detecting the fraction of the total volume occupied by the infarct and for studying the effect of various proposed therapies upon this infarcted volume.
Proc Natl Acad Sci U S A 1976 Dec
PMID:Phosphorus nuclear magnetic resonance studies on normoxic and ischemic cardiac tissue. 1 7

The effects of changes in the pH of Tyrode's solution on the responses of isolated guinea pig ileum preparation to acetylcholine and histamine were studied. At higher levels of pH (increased alkalinity), the responses of the tissue to both acetylcholine and histamine were increased. At lower pH levels (increased acidity), the response of the tissue to acetylcholine was increased but that to histamine was reduced.
Bangladesh Med Res Counc Bull 1976 Dec
PMID:Effects of changes in pH of bath fluid on isolated guinea pig ileum preparation. 1 38

It has generally been thought that homeostatic mechanisms of renal origin are responsible for minimizing the alkalemia produced by chronic hypocapnia. Recent observations from this laboratory have demonstrated, however, that the decrement in [HCO(-) (3)], which "protects" extracellular pH in normal dogs, is simply the by-product of a nonspecific effect of Paco(2) on renal hydrogen ion secretion; chronic primary hypocapnia produces virtually the same decrement in plasma [HCO(-) (3)] in dogs with chronic HCl acidosis as in normal dogs (Delta[HCO(-) (3)]/DeltaPaco(2) = 0.5), with the result that plasma [H(+)] in animals with severe acidosis rises rather than falls during superimposed forced hyperventilation. This observation raised the possibility that the secondary hypocapnia which normally accompanies metabolic acidosis, if persistent, might induce an analogous renal response and thereby contribute to the steady-state decrement in plasma [HCO(-) (3)] observed during HCl feeding. We reasoned that if sustained secondary hypocapnia provoked the kidney to depress renal bicarbonate reabsorption, the acute salutary effect of hypocapnia on plasma acidity might be seriously undermined. To isolate the possible effects of secondary hypocapnia from those of the hydrogen ion load, per se, animals were maintained in an atmosphere of 2.6% CO(2) during an initial 8-day period of acid feeding (7 mmol/kg per day); this maneuver allowed Paco(2) to be held constant at the control level of 36 mm Hg despite the hyperventilation induced by the acidemia. Steady-state bicarbonate concentration during the period of eucapnia fell from 20.8 to 16.0 meq/liter, while [H(+)] rose from 42 to 55 neq/liter. During the second phase of the study, acid feeding was continued but CO(2) was removed from the inspired air, permitting Paco(2) to fall by 6 mm Hg. In response to this secondary hypocapnia, bicarbonate concentration fell by an additional 3.0 meq/liter to a new steady-state level of 13.0 meq/liter. This reduction in bicarbonate was of sufficient magnitude to more than offset the acute salutary effect of the hypocapnia on plasma hydrogen ion concentration; in fact, steady-state [H(+)] rose as a function of the adaptive fall in Paco(2), Delta[H(+)]/Delta Paco(2) = -0.44. That the fall in bicarbonate observed in response to chronic secondary hypocapnia was the result of the change in Paco(2) was confirmed by the observation that plasma bicarbonate returned to its eucapnic level in a subgroup of animals re-exposed to 2.6% CO(2). These data indicate that the decrement in plasma [HCO(-) (3)] seen in chronic HCl acidosis is a composite function of (a) the acid load itself and (b) the renal response to the associated hyperventilation. We conclude that this renal response is maladaptive because it clearly diminishes the degree to which plasma acidity is protected by secondary hypocapnia acutely. Moreover, under some circumstances, this maladaptation actually results in more severe acidemia than would occur in the complete absence of secondary hypocapnia.
J Clin Invest 1977 Dec
PMID:The maladaptive renal response to secondary hypocapnia during chronic HCl acidosis in the dog. 2 Nov 98

Aqueous solutions of polysorbate 20 undergo autoxidation on storage, with the peroxide number increasing and subsequently decreasing again, the acidity increasing continuously, the pH and surface tension falling and tending to level off, and the cloud point dropping sharply until turbidity begins at room temperature. The changes are accelerated by light, elevation of temperature, and a copper sulfate catalyst. At the same time, hydrolysis occurs, liberating lauric acid. Analysis of the alterations in these properties leads to the conclusion that hydrolysis has the major influence near room temperature and that oxyethylene undergoes chain shortening at temperatures above 40 degrees. However, evidence of degradation is detectable even in previously unopened commercial samples of polysorbates 20, 40, and 60, warranting attention to the stability of and standards for these surfactants as compared with the solid alkyl ether type of nonionic surfactant.
J Pharm Sci 1978 Dec
PMID:Autoxidation of polysorbates. 3 49

Metabolic acidosis is common in babies fed cows' milk-based formulae. Therefore the effects of adding alkaline salts (sodium and potassium citrate) to a demineralised whey formula were studied in vitro and in 26 low birthweight babies fed on the formula or formula plus citrate. The alkali altered the pH and titratable acidity to a value nearer human milk but it increased the buffering capacity to a value further away. This may effect the bacterial flora of the intestine. The babies fed on formula plus citrate did not make greater gains in weight, length, head circumference, skinfold thickness, or midarm muscle circumference, although they had a greater blood base excess. Some of these babies developed a mild metabolic alkalosis and 3 had hyponatraemia despite their increased sodium intakes. These babies also had lower levels of plasma transferrin but showed no differences in urea, albumin, cholesterol, and calcium levels. No baby fed on the demineralised whey formula without added citrate had a base deficit exceeding 5 mmol/l; late metabolic acidosis is less common in babies fed on this formula and the routine addition of alkali can have untoward metabolic effects.
Arch Dis Child 1978 Dec
PMID:Milk pH, acid base status, and growth in babies. 3 63

Studies were performed on 12 patients with idiopathic hypercalciuria to evaluate the hypothesis that the acid load accompanying potassium acid phosphate would adversely affect renal calcium reabsorption and citrate excretion compared to the neutral form of the phosphate salt. During acute clearance studies, neutral phosphate (NP) led to a fall in FECa (2.2 +/- 0.6% to 0.8 +/- 0.1%, P less than 0.02) and no change in titratable acidity (TA) or net acid excretion (NAE). Acid phosphate (AP) did not reduce FECa acutely, and led to a rise in TA (22 +/- 4 to 62 +/- 6 muEq/min, P less than 0.02) and NAE (46 +/- 6 to 6 89 +/- 7 muEq/min, P less than 0.02). During chronic administration, AP resulted in higher urinary calcium excretion in both absorptive (187 +/- 29 vs. 141 +/- 18 mg/day, P less than 0.02) and renal hypercalciuric patients (233 +/- 24 vs. 173 +/- 190.02 mg/day, P less than 0.02). Also, TA and NAE were higher following AP, whereas citrate excretion was lower (375.4 +/- 64.6 vs. 633.4 +/- 28.8 mg/day, P less than 0.01). These data suggest that the reported ineffectiveness of AP in the therapy of nephrolithiasis may be related to the deleterious effects of the acid load on calcium and citrate metabolism.
Kidney Int 1979 Dec
PMID:Differing effects of acid versus neutral phosphate therapy of hypercalciuria. 4 88

Attachment of substituted phenyl side chains at N1 of 6-azauracil caused striking increases in plasma life and anticoccidial potency. The increases were related in part to the acidity of the imide hydrogen. Maximum effects were shown by phenyl rings substituted in both meta positions by compact, electron-withdrawing, lipophilic substituents, as in 1-(3',5'-dichlorophenyl)-6-azauracil, which had plasma half-life of 160 h and a potency 250-fold greater than that of 6-azauracil.
J Med Chem 1979 Dec
PMID:Anticoccidial derivatives of 6-azauracil. 2. High potency and long plasma life of N1-phenyl structures. 58 29

Activity of peptic cells is influenced directly by cholinolytic or cholinergic agents. Histamine H2-antagonists influence the activity of the chief cells through changes of acidity of gastric juice.
Experientia 1977 Dec 15
PMID:Influence of metiamide and atropine on pepsinogen secretion in the conscious rat. 59 Apr 54

Ultrastructural changes taking place in various phases of secretion in the gastric fundus parietal cells after histamine adminstration were studied in patients suffering from gastric and duodenal ulcers, having different gastric acidity. Parietal cells of patients with normal and hyperacidity of the gastric juice after histamine administration were found to have such ultrastructural alterations in which were characteristic of the intensively functioning cells, with the retention of phasic character of the process; as to patients with hypoacidity, the secretory phases of the parietal cells were not marked, and no alterations indicating intensification of the cellular functional activity were noted.
Biull Eksp Biol Med 1977 Dec
PMID:[Ultrastructural changes in the parietal cells of persons suffering gastric ulcers]. 59 15


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