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)

1. In the isolated tibia of the cat, perfused with blood from its own carotid connected to popliteal artery via a pump, infusion of porcine thyrocalcitonin causes an arteriovenous difference in calcium concentration of up to 5%, corresponding to net retention of calcium in bone.2. When taken in conjunction with determinations of radiocalcium clearance in the tibia, the effect is of the right order of magnitude to account for the hypocalcaemic action of thyrocalcitonin in the whole animal.3. Calcium retention was accompanied by a small increase in acidity of outflowing venous blood whereas verification of the hypothesis of calcium regulation by pH change in the bone substance would require a decrease.
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PMID:The effect of thyrocalcitonin on blood-bone calcium equilibrium in the perfused tibia of the cat. 605 43

Following previous demonstration that isoproterenol stimulated and norepinephrine inhibited gastric acid secretion induced by secretagogues, role of adrenergic agonists was studied by measuring acidity the peptic activity of the effluent of the perfused rat stomach. Response of gastric secretion to isoproterenol was increased by theophylline treatment but was not affected by metiamide treatment. N6, O2'-Dibutyryladenosine 3', 5'-cyclic monophosphoric acid sodium salt monohydride (dibutyryl-c-AMP) stimulated gastric secretion in a dose-dependent manner. These results suggest the possibility that the action of isoproterenol in gastric acid secretion is mediated by c-AMP. However, gastric secretion induced by pentagastrin, histamine, or carbamylcholine was not affected by theophylline treatment. N2, O2'-Dibutyrylguanosine 3', 5'-cyclic monophosphoric acid sodium salt (dibutyryl-c-GMP) did not exert any effect on gastric secretion. Depression of pentagastrin-induced gastric secretion by norepinephrine was reversed by EGTA infusion. Moreover, Ca2+, depressed pentagastrin-induced gastric secretion. These results suggest that the action of norepinephrine is closely related to the concentration of Ca2+.
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PMID:Role of adrenergic agonists on gastric secretion in the rat. 611 Jul 14

Losses of Ca2+, Mg2+ and primary amines into waters between pH = 5 and 3 from eyed Chinook salmon eggs, Oncorhynchus tshawytscha , and gills excised from the freshwater, bivalve mollusc Anodonta californiensis were measured and compared to effluxes into distilled water. Sulfuric, nitric and hydrochloric acids were used. Even at pH = 5 losses of Ca2+ and Mg2+ from both biological systems occur at short times, minutes, and can exceed those found in water of higher pH (non-acid waters). Increasing acidity increases short term primary amine loss from both systems. For both divalent cation and amino acid losses gills of A. californiensis are more sensitive to acidity than eggs of O. tshawytscha .
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PMID:The effect of acid water on the loss of divalent cations and primary amines from natural membranes. 614 37

The local anaesthetic effect of cationic, anionic, and neutral alkyl amphipathic agents was similarly enhanced in an apparently nonspecific way by circumstances which modulate electrostatic interactions (acidity, modification of charged groups at the sarcolemmal surface by group-specific reagents, or changes in the calcium concentration), presumably as the result of secondary effects on the conformation of membrane proteins. However, the selective enhancement of the local anaesthetic effect of alkyl trimethylammonium compounds by perchlorate implies a more specific interaction which may influence the penetration of hydrophobic groups into the membrane interior.
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PMID:The role of electrostatic interactions in modulating the local anaesthetic effects of amphipathic agents in frog skeletal muscle. 632 94

A novel autophosphorylating protein kinase, autophosphorylating protein kinase 500, independent of cyclic AMP, cyclic GMP, calcium, and calmodulin was purified from rat adrenocortical carcinoma 494 by ammonium sulfate fractionation followed by the chromatographic steps of DEAE-cellulose, gel filtration, cyclic AMP-epoxy Sepharose, and phosphocellulose. Sometimes two additional chromatographic purification steps of chromatofocusing and gel filtration were necessary for complete purification. The enzyme was homogeneous as evidenced by one- and two-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Sucrose density sedimentation studies indicated that Mr of the enzyme was 490,000, while ultracentrifugal analysis demonstrated a value of 481,400 (+/-7%). The protein was composed of two identical subunits each with Mr = 250,000. The enzyme molecule was slightly asymmetric with frictional and sedimentation coefficients of 1.28 and 18.20, respectively, and a Stokes radius of 66 A. Isoelectric focusing electrophoresis revealed a single peak with pI 4.6, indicating acidity of the protein. The enzyme self phosphorylated one or more of its serine residues. The reaction utilized the terminal phosphate of ATP; GTP was inactive. Divalent cations (5 mM Mn2+ or 10 mM Mg2+) were essential for optimum activity. Autophosphorylating protein kinase 500 did not phosphorylate the commonly used exogenous substrates such as histones, casein, phosvitin, or protamine. Analysis of autophosphorylating protein kinase 500 with rabbit anti-autophosphorylating protein kinase 500 IgG by immunoelectrophoresis and crossed immune electrophoresis demonstrated single arcs of precipitation, confirming the biochemical demonstration of enzyme purification and homogeneity. Indirect immunofluorescence studies revealed an intracytoplasmic localization of the enzyme in cultured and freshly isolated adrenocortical carcinoma 494 cells. Both cell types revealed an intensity of perinuclear enzyme fluorescence, but an absence of the enzyme in the nuclei or nucleoli. The anti-autophosphorylating protein kinase 500 IgG blocked the self-catalyzed phosphorylation of autophosphorylating protein kinase 500, providing immunological support of the biochemical results that autophosphorylation is an intrinsic characteristic of the enzyme. When autophosphorylating protein kinase 500 was incubated with membrane-bound ribosomes, it phosphorylated a Mr = 31,000 protein. This phosphorylation was blocked by the anti-autophosphorylating protein kinase 500 IgG.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Rat adrenocortical carcinoma 494 autophosphorylating protein kinase, autophosphorylating protein kinase 500. Purification, biochemical and immunological characterization, and substrate specificity. 637 Oct 13

The biochemical profile [levels of calcium, phosphorus, magnesium, chlorides and iron, the activities of alkaline phosphatase (ALP), aspartate aminotransferase (AST) and alanine aminotransferase (ALT), and the concentrations of total protein, albumin, cholesterol, urea, glucose, and vitamins A and E] was studied in the blood serum of 40 anoestrous and 40 control inseminated animals in a production herd with an increased occurrence of anoestrus in gilts. The anoestrous gilts showed significantly lower levels of albumin (P less than 0.01) and glucose (P less than 0.01) and ALP activity (P less than 0.05), and significantly higher concentrations of urea (P less than 0.01), vitamin A (P less than 0.01) and vitamin E (P less than 0.05) and ALT activity (P less than 0.05), as compared with the inseminated controls. An extended enzymatological examination consisting of the evaluation of the activities of ALP, AST, ALT and gamma-glutamyl transferase (GMT) was performed in another set of 22 anoestrous and 20 mated gilts. The anoestrous gilts showed a statistically significant increase in the activities of AST (P less than 0.01), GMT (P less than 0.01) and ALT (P less than 0.05) and an insignificant increase in the activity of ALP in comparison with the control animals. The comparison of the obtained values of the studied biochemical criteria with literary data indicated a lower concentration of magnesium and a higher ALP and ALT activities in the anoestrous and inseminated gilts in both groups under study. A high acidity of fat and a medium to high fungus infestation (Mucor sp., Aspergillus sp.) were found by chemical and mycological examination of the administered feed mixtures. The histological examination of the ovaries of anoestrous animals showed cystically degenerative changes, proliferations of fibrous elements, and partial atrophy of ovarial cortex. It has been inferred from the observations that mycotoxins may be involved in the increase in the occurrence of anoestrus, either by a direct effect on sexual organs or by impairing the function of liver which, secondarily contributes to the rise of ovarial dysfunctions.
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PMID:[Changes in selected biochemical indicators in blood serum in anestrous gilts]. 640 28

Ingestion of protein is known to increase urinary calcium excretion. By studying the effect of intravenous amino acid infusion on calcium excretion, the variables of diets and intestinal absorption are avoided. Five patients on total parenteral nutrition with otherwise constant nutrient infusions containing 240 mg of calcium were randomized to two different levels of amino acid infusion. On 1 g/kg ideal body weight amino acid infusion, two patients excreted more than 240 mg of calcium in the urine, while on 2 g/kg ideal body weight amino acid infusion all five patients lost more calcium in urine than was infused. Mean urinary calcium excretion was increased from 287 to 455 mg/day. On the higher amino acid dose, mean glomerular filtration rate increased from 102 to 143 ml/min. There was no effect of amino acid dose on serum calcium, ionized calcium, parathyroid hormone, and 25 (OH) vitamin D. Calcium excretion corrected for the glomerular filtration rate was increased at the higher amino acid dose, indicating a decrease in renal calcium reabsorption. Daily urinary excretion of sulfate, ammonia, and titratable acidity were increased during the high amino acid infusion. Hypercalciuria induced by high levels of amino acid infusion during total parenteral nutrition may contribute to the development of metabolic bone disease.
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PMID:Amino acid-induced hypercalciuria in patients on total parenteral nutrition. 641 Aug 98

In previous studies, a 5-min inhalational challenge with 10% citric acid aerosol (0.52 M) elicited bronchoconstriction in Basenji-Greyhound (BG) dogs with hyperreactive airways but not in mongrel dogs. This response was independent of vagal reflexes because it was not attenuated by atropine. Citric acid might elicit bronchoconstriction because of acidity, calcium chelation, or some other effect of the citrate molecule. To assess these factors, barbiturate-anesthetized BG dogs were challenged (5 min) with aerosols of 10% acetic acid or a citric acid (0.48 M)/Na3citrate (0.04 M) mixture of equivalent pH, 6% Na2-ethylenediaminetetraacetic acid (EDTA), or 6% CaNa2EDTA. Each challenge was delivered in a separate week. The acidity alone was not an adequate stimulus, since pulmonary resistance (RL) was unaltered by 10% acetic acid, although markedly increased by the citric acid-Na3citrate mixture [2.2 +/- 0.4 (SE) cmH2O X l-1 X s prechallenge, 10.0 +/- 2.2 postchallenge]. Aerosols of Na2EDTA provoked a similar increase in RL (2.1 +/- 0.4 cmH2O X l-1 X s prechallenge, 9.0 +/- 1.8 postchallenge). Neither effect was attenuated by intravenous atropine (0.2 mg/kg). CaNa2EDTA caused no changes in RL. We conclude that it is the calcium chelating action of citric acid rather than its acidity that is responsible for bronchoconstriction in BG dogs with hyperreactive airways.
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PMID:Importance of calcium in citric acid-induced airway constriction. 641 82

The effects of diltiazem on pentagastrin-induced gastric secretion were studied in 11 normal volunteers. Diltiazem 60 mg thrice daily for 10 doses did not produce any clear-cut effect on the increase in gastric acidity induced by either standard or low doses of pentagastrin. Despite the role of calcium on gastric secretion, diltiazem does not show promise as an agent capable of reducing gastric acidity.
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PMID:Effect of diltiazem on pentagastrin-induced gastric secretion in man. 649 Feb 40

We analyzed 24 intrahepatic gallstones for their components by chemical assay and evaluation of atomic absorbance. Those with high cholesterol and fatty acid contents were noted in addition to conventional bilirubin-calcium gallstones, and a mean cholesterol content of over 50% was observed in one fourth of the hepatic gallstones. Measurement of biliary bilirubin and calcium levels conducted to investigate the causative factors of bilirubin gallstones showed that they occur more readily in bile containing less bilirubin, suggesting that their development is largely dependent on the amount of bile acids in hepatic bile determined by the biliary acidity, presence of unconjugated bilirubin, and ionization of calcium. Our results suggest the necessity of treating hepatolithiasis as a hepatic disease with constitutional implications and, in the absence of clear insight into its etiology, of selecting surgical modes always with proper consideration to the possibility of recurrence. Therefore, choledochojejunostomy combined with jejunostomy is our primary surgical procedure.
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PMID:[Treatment of hepatolithiasis--current problems in view of analysis of stones]. 650 68


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