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

A review of the effect on metabolism of antacids, anticholinergics and histamine H2-antagonists is given. It is stated that long-term treatment with antacids by a variety of mechanisms can cause severe metabolic complications such as the milk-alkali syndrome and phosphorus depletion. The interaction with other drugs can also be marked. There is very little known of the effect of anticholinergics on metabolism. Clinical experience has not indicated that any serious consequences will occur. The authors have investigated the effect continuous treatment with cimetidine 400 mg at night or twice daily for three years on weight, haemoglobin, plasma iron, plasma folate, plasma vitamin B12, albumin and plasma calcium. The only significant difference that occurred was a slight decrease of plasma calcium within the reference values. In conclusion it is stated that there is very little indication that the moderate and inconstant reduction of acidity over 24 hours which can be achieved by anticholinergics or twice daily administration of presently available H2-antagonists will result in metabolic consequences arising from reduced acidity. Higher doses given more frequently might give a risk for bacterial overgrowth with metabolic consequences.
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PMID:Metabolic consequences of reduced gastric acidity. 286 50

This report summarizes a study of the chemical and biological characteristics of three oligotrophic lakes located in a region that receives a moderately acidic precipitation (mean annual pH 4.5-4.6), and a sulfate deposition of about 20 kg/ha/yr. The two brownwater lakes are relatively acidic (pH 4.5 and 4.8), and much of their acidity is attributable to organic anions. The brownwater lakes also have a large concentration of aluminum and iron, but these are bound to dissolved organic matter and are relatively non-toxic to biota. Average phytoplankton production was largest in the clearwater lake. This was due to its relatively deep euphotic zone, since the average unit-volume productivity did not differ much among the lakes. In fact, productivity at light optimum was largest in the most acidic brownwater lake, probably because of its larger phosphorus concentration. The clearwater lake had extensive macrophyte vegetation, which covered its bottom to a depth of 6.5 m. In the brownwater lakes, macrophytes were confined to shallow nearshore water because of the limited water transparency. Zooplankton density and biomass were largest in the most acidic brownwater lake, probably because of allochthonous organic particulates and little fish predation. Benthic invertebrates were abundant in all three lakes, and were dominated by insects, especially Chironomids. Lakes in the study area appear to be sustaining fish populations at more acidic pHs than elsewhere. This may be due to the large concentration of dissolved organic matter in many lakes, which complexes and partially detoxifies metals such as aluminum.
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PMID:Characteristics of three acidic lakes in Kejimkujik National Park, Nova Scotia, Canada. 292 90

Changes of urinary pH, titratable acidity, ammonium, bicarbonate and PCO2, as well as plasma insulin and various plasma and urine electrolytes were studied in 15 normal individuals during a 5-hr glucose tolerance test. After glucose ingestion, urine pH and bicarbonate excretion rose while urine titratable and total acidity, ammonium, Na, K, Cl, phosphorus and PCO2 fell significantly. Serum bicarbonate rose while serum potassium, phosphorus, and anion gap decreased following oral glucose administration. Glucose feeding and the resultant rise in insulin are, therefore, associated with a considerable reduction in urine acidity and Na, K, Cl, and phosphorus excretion. While a significant fall in urinary Na, K and phosphorus has been shown to occur following glucose and insulin administration, their effect on renal H+ excretion in man has not been investigated previously. The mechanism of the observed fall in urine acidity is not clear and requires further investigation.
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PMID:Effects of glucose feeding on renal electrolyte and H+ transport. 299 96

The effects of varying extracellular pH on the rates of uptake of titratable anions by human erythrocytes under conditions of constant intracellular pH have been determined for a series of highly related anions, the phosphate "analogs." These compounds are simply substituted phosphorus oxyacids, differing in the number and acidity of titratable protons: phosphate (HPO4(2-), pKa 6.8); phosphite (HPO3(2-), pKa 6.4); hypophosphite (H2PO2-); methylphosphonate ((CH3)PO3(2-), pKa 7.4); dimethylphosphinate ((CH3)2PO2-); fluorophosphate [PO3F2-, pKa 4.7); and thiophosphate (HSPO3(2-), pKa 5.5). Suspensions of intact, Cl(-)-loaded erythrocytes (intracellular pH, 7.2) were incubated at 37 degrees C in isotonic buffers (pH 4-8) containing 60 mM phosphate analog for specified time intervals, whereupon influx was halted by the addition of 1 mM 4-acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic acid (SITS), an inhibitor of anion exchange. The intracellular anion concentrations were determined from 31P or 19F nuclear magnetic resonance spectra from the erythrocyte suspensions. The influx rates for the titratable phosphate analogs exhibited bimodal pH dependence, reaching maximal levels at pH values that increased with increasing anion pK. This pH-dependent behavior is consistent with a transport channel that contains a titratable regulatory site which interacts with the translocated anion. Based upon the Henderson-Hasselbalch equation, the probability that a titratable anion will have an electric charge of equal magnitude to that of the titratable carrier is highest at a pH value exactly midway between the pK of the regulatory site and that of the anion. The pH maxima observed for the phosphate analogs indicate a pK for this site of 5.5 at 37 degrees C. Intracellular pH changes associated with influx indicated that transport of the "fast" anion phosphite is largely in monoionized form. Intracellular pH changes associated with transport of slow anions were predominantly determined by partial ionic equilibrium effects and did not indicate the ionization state of the transported anion.
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PMID:The pH dependence of red cell membrane transport of titratable anions studied by NMR spectroscopy. 333 37

The titratible carrier model for erythrocyte anion transport predicts that the pH dependence of titratible anion transport should differ considerably from that for monovalent or divalent anions. The effects of pH on titratible anion influx rates have been determined for a series of related anions, the phosphate "analogs". These compounds are simply substituted phosphorus oxyacids, differing in the number and acidity of titratible protons. Influx of each analog at 60 mM concentration into Cl- loaded erythrocytes at constant intracellular pH (7.2) was measured over an extracellular pH range of 4.0 to 8.0 using 31P or 19F nuclear magnetic resonance spectroscopy. Influx rates peaked at pH values that increased with increasing anion pK. Using the Henderson-Hasselbalch equation to determine the effects of pH on the charges carried by a titratible anion and a titratible carrier, the pH at which the anion would most likely have the same charge as the carrier was found to be exactly midway between their respective pK values. The observed pH maxima for the phosphate analog influx curves are consistent with transport by a titratible carrier having a pK of 5.5.
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PMID:The pH dependence of red cell membrane transport of titratible anions. An NMR study. 359 19

The phosphate analogs are a series of chemically related small anions based upon tetrahedrally bonded phosphorus. Each compound is a mono- or disubstituted phosphorus oxyacid. These chemical substitutions lead to differences in the number and acidity of titratable protons, differences in molecular structures and charge distributions, and unique 31P, 19F, or 1H nuclear magnetic resonance spectra for each analog. These compounds include phosphate, phosphite, hypophosphite, fluorophosphate, thiophosphate, methylphosphonate, and dimethylphosphinate. NMR spectra were obtained from human erythrocytes suspended in buffers containing phosphate analogs. Intracellular and extracellular 31P and 19F chemical shifts of these anions were found to be nonequivalent, due to magnetic susceptibility differences between the two compartments, as well as to the transmembrane pH gradient. NMR spectroscopy was used to measure erythrocyte influx rates of the phosphate analogs, as well as the intracellular and extracellular pH changes that accompany influx, in red cell suspensions incubated for selected time intervals. Anion influx rates were found to vary over three orders of magnitude among the phosphate analogs. All analogs showed concentration-dependent influx rate saturation. The major determinant of influx rates was neither the molecular weight of the analog nor the net charge on the anion, but rather the structure of the anion. Phosphite (HPO2-3), the anion most closely resembling bicarbonate (a natural substrate for anion exchange) was found to have the highest influx rate.
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PMID:Erythrocyte anion transport of phosphate analogs. 379 27

It has recently been documented that a small amount of aluminum is absorbed from a variety of different orally administered aluminum compounds. A variety of factors including gastric acidity, fluoride ingestion, parathyroid hormone, vitamin D and the quantity of aluminum ingested could theoretically modulate aluminum absorption from the gastrointestinal tract. However, partially because of the unavailability of an aluminum isotope, knowledge regarding factors which modify aluminum absorption is quite limited. In healthy individuals the absorbed aluminum is largely eliminated from the body by the kidneys. However, with renal failure the absorbed aluminum is retained and can markedly alter the body aluminum burden with resulting toxicity. In view of this finding, it is suggested that uremic patients receive the smallest amount possible of aluminum-containing, phosphate-binding gels consistent with the control of serum phosphorus levels and that alternate methods for the control of the serum phosphorus should be sought.
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PMID:Gastrointestinal absorption of aluminum. 391 61

The influence of feedstuffs treated with ionizing radiation on the nutrition of dogs was tested in four groups of animals. Two groups were administered for 90 days a ration, the main part of which (VETACAN meat feed mixture and VETAVIT loose feed mixture) was irradiated with radioisotope Co 60 of the intensity of 25 kGy/kg, in other two groups of dogs the nonirradiated ration was used for the same time period. The control groups of dogs were put together for these two diets. The laboratory examination of irradiated feedstuffs confirmed their complete microbiological and mycological intactness. However, the irradiation brought about a significant 35% degradation of essential amino acids with an increase of ammonia nitrogen, destructive changes in the lipid component of feedstuffs and a partial decomposition of the saccharide part of the VETAVIT feed mixture, expressed by the acidity of water extract. The sensory evaluation of irradiated feedstuffs did not show any perceptible alterations. The haematological examination of the blood of animals, which had been administered irradiated feed rations, demonstrated a significant negative influence on the blood picture. The biochemical examination of the blood serum and plasma revealed that total proteins of experimental dogs dropped and the creatinine level was also significantly decreased. Neither was the level of carbohydrate nutrition nor the energy saturation affected by irradiation. The glucose levels in the blood serum of dogs fluctuated within the range of physiological reference values. The growth of free ammoniacal bases of feedstuffs, evoked by ionizing radiation, conditioned obviously the level of actual pH of blood in dogs as determined in this study. The destruction of lipoid fraction in the feedstuffs induced a decrease in the activity of lipophile retinol and thus the biological value of feeds was impaired. The biochemical examination of ALT, AST and ALP enzyme activity did not show any increased activity of parenchyma, in particular of liver cell. A decisive role of the biological quality of feed ration for utilization of some minerals was demonstrated by a significant decrease of the magnesium level in animals administered irradiated feed rations without any biological supplementation. On the contrary, the potassium, calcium and phosphorus levels did not reflect this dietary difference between the groups.
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PMID:[The effect of feeds treated with ionizing irradiation on biochemical indicators of the nutritional value of energy nutrients]. 393 33

The composition of bulk milk of 18 herds of ewes and 14 herds of goats and the milk of 10 individual animals of each ewes and goats during a 12 weeks lactation period was studied. The average percentage of acidity of bulk ewe's milk (0.22), fat (6.4), lactose (4.3), total nitrogen (0.9) calcium (0.169), ash (0.940) and total solids (18.6) were higher than 0.17, 4.0, 3.9, 0.62, 0.130, 0.81 and 12.8 of bulk goat's milk. Phosphorus (0.074) was almost similar to (0.077), while non-protein nitrogen (0.0022) was about thirteen times lower than 0.028 of goat's milk. Determined parameters increased, whereas lactose and non-protein nitrogen decreased with progression of the lactation period. Individual ewe's milk occasionally contained 1.4% fat and 0.56% total nitrogen closely resembling individual goat's milk.
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PMID:The composition of Karadi ewe's and goat's milk. 399 Jul 86

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


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