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)

Proton magnetic resonance studies of the acid-base chemistry of the glycyl ammonium, histidyl imidazolium, and lysyl ammonium groups of glycyl-L-histidyl-L-lysine and of the glycyl ammonium and histidyl imidazolium groups of glycyl-L-histidine and glycyl-L-histidylglycine are described. Chemical-shift data indicate that, at the molecular level, the glycyl ammonium and the histidyl imidazolium groups are titrated over the same pH range, with the acidity of the imidazolium group some 8 to 10 times that of the glycyl ammonium group, depending on the peptide. The lysyl ammonium group of Gly-His-Lys is much less acidic and is titrated over a higher pH range. Microscopic and macroscopic acid-dissociation constants were determined from chemical-shift data for each of the peptides. It is shown how microscopic formation constants for protonated metal complexes of these ligands, which are being used increasingly as models for the binding of metal ions by proteins, can be calculated from the macroscopic formation constants and the microscopic acid-dissociation constants. The acid-base chemistry of Gly-His-Lys is discussed with respect to its recently discovered biological activity.
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PMID:Determination of the microscopic and macroscopic acid dissociation constants of glycyl-L-histidyl-L-lysine and related histidine peptides. 1 68

Eleven infants recovering from protein-calorie malnutrition secondary to acquired monosaccharide intolerance were found to have reduced plasma bicarbonate concentration associated with inadequate weight gain. Renal net acid excretion (NAE) was decreased to a mean of 34.2 micronEq/1.73m2/min. Titratable acidity (TA) was markedly reduced, accounting for only 16% of NAE. This marked reduction in TA was associated with reduced mean phosphate (PO4) excretion (.074 mg/min) and a reduced mean serum PO4 (3.9 mg/dl), suggesting PO4 depletion. Two patients received intravenous phosphate loads, resulting in an increase in mean NAE from 35.1 to 89.7 microgEq/1.73m2/min. A similar response was seen after oral PO4 supplementation. Three patients were studied after partial correction of their acidosis. At a relatively low plasma bicarbonate concentration (mean = 16.6 mmoles/liter) significant amounts of bicarbonate were detected in the urine (mean = 8.7 micronEq/1.73m2/min), suggesting a defect in bicarbonate reabsorption. Five patients studied after complete recovery from malnutrition had normal NAE in response to ammonium chloride load. The reduction in NAE appears to be secondary to unavailability of urinary buffers and a reduction in bicarbonate reabsorption; both of these defects can be explained by phosphate depletion.
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PMID:Reduced renal acid excretion in malnutrition: a result of phosphate depletion. 1 94

The renal capacity of acidification of urine was studied in 21 patients with hypergammaglobulinemia (polyclonal gammapathies) secondary to several conditions. The reabsorption threshold of bicarbonate was determined by Rodriguez-Soriano's technique; the acid and ammonium production was measured using Wrong and Davies' technique. Values for the bicarbonate threshold ranged from 18.5 to 29 mmol/liter of plasma bicarbonate with a mean value of 25 +/- 2.29; they were not significantly different from the control values. Urinary pH ranged from 4.6 to 5.8; ammonium excretion ranged from 18.4 to 114.5 microEq/min (mean value 63.01 +/- 25.36). Acidity values ranged from 13 to 65.05 microEq/min (mean value 33.61 +/- 19.36). Thhre was no statistical difference between these values and those obtained from the controls. We found no evidence that the acidification function of urine was limited in patients with hypergammaglobulinemia secondary to several conditions as compared with normal subjects. In the two cases in which this function was altered there was no reason why it should be attributed to hypergammaglobulinemia.
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PMID:[Study of the acidification capacity of the urine in polyclonal hypergammaglobulinemia (author's transl)]. 4 38

Chronic metabolic acidosis entails hyperparathyroidism and osteopathy. In order to elucidate the role of the thyroparathyroids in this bone lesion production the effects of acidic diet for 7 weeks were studied in parathyroidectomized (PTX), thyroparathyroidectomized (TPTX) and shamoperated (Sh-O) growing rats. In all animals urinary excretion of calcium, phosphate, ammonium and titrable acidity was similarly increased. The rise in hydroxyproline excretion and urinary 85-sr (that was injected previous to acidic feeding) was more marked in PTX and TPTX rats. Moreover, in these animals the serum calcium level was increased, the blood pH was decreased. According to these data, an acidic diet intake that is not sufficient to elicit a fall in blood pH of normal young rats can induce severe acidosis in chronically parathyroidectomized or thyroparathyroidectomized animals; moreover the bone resorption appears more marked. It is concluded that parathyroids are involved in the extra-cellular fluid defense mechanism against acidosis by a no bone resorptive mechanism. We hypothesize that the parathyroids permit the necessary and adequate supply of bicarbonates by the bone to maintain blood pH homeostasis.
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PMID:[Acid-base homeostasis and the thyro-parathyroid glands]. 23 51

In acute experiments, aldosterone (aldo), 18-hydroxycorticosterone (18 OH B) or corticosterone (B) were administered to adrenalectomized rats and parameters related to acid-base balance measured in urine samples collected for 3.5 hours after injection. Aldo reduced sodium excretion but did not affect pH nor the outputs of K, NH4+, CO3H-, phosphates nor titratable acidity. 18 OH B increased the excretion of titratable acidity and reduced drastically that of CO3H-. The lowest effective dose (3 micrograms) promoted Na excretion while the highest dose employed (6 micrograms) reduced pH and Na excretion. B increased the excretions of phosphates and ammonium, the former drastically. Potassium output either increased or did not change, and pH augmented marginally. It is postulated that a) 18 OH B is a naturally occurring steroid eliciting urine-acidification not necessarily accompanied by sodium retention; and b) at least B and 18 OH B in the rat, possess hormonal roles according to which the latter promotes the presence of protons, and the former, that of acute proton-acceptors in the lumen of tubuli.
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PMID:Acute effects of three natural corticosteroids on the acid-base and electrolyte composition of urine in adrenalectomized rats. 26 23

Acute clearance studies were performed in normal subjects to establish the site(s) and mechanism of action of the new diuretic agent, bumetanide (3-n-butylamino-4-phenoxy-5-sulfamylbenzoic acid), in the human kidney. When the drug was administered during water diuresis, solute-free water formation was unchanged associated with a peak increment in fractional sodium excretion of approximately 15% of filtered load. However, studies performed in hydropenic subjects demonstrated a virtual abolition of free water reabsorption. The diuretic caused a mild phosphaturia which did not appear to be related to alterations in parathyroid hormone. Furthermore, whereas net hydrogen ion excretion and urinary pH were unchanged, the excretion of ammonium ion, titratable acidity and bicarbonate all increased mildly. Taken together, the data suggest that the primary site of action of bumetanide is the medullary portion of the ascending limb of the loop of Henle, but that in addition, bumetanide inhibits the transport of sodium in the proximal nephron. Despite the fact that the drug is a sulfonamide derivative, its proximal activity seems unrelated to a carbonic anhydrase inhibitory effect. More likely the agent interferes with proximal reabsorption by impairing sodium-phosphate linked transport.
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PMID:Study of the sites and mechanisms of action of bumetanide in man. 85 Jan 44

After World War II the incidence of urolithiasis increased consistently among the general population in this country. Nearly 25% of all examined renal calculi contain uric acid, sodium acid urate or ammonium acid urate as constituents. There are two peaks in lifespan of occurring urate stones: in the adolescence and in the age between 40 and 60 years. The following conditions are due to the formation of uric acid-containing stones: 1. Gout and primary hyperuricemia; 2. secondary hyperuricemia; 3. idiopathic cases with normal renal excretion of uric acid and normouricemia, but with a higher degree of acidity of the urine than normal considering the total renal excretion of acid products; 4. iatrogenic hyperuricemia during insufficient uricosuric therapy. Up to more than 30% of all the patients with recurrent formation of oxalate stones show a clear association with hyperuricemia, hyperuricosuria and increased renal excretion of calcium. In the presence of sodium urate a considerable promotion of precipitation of crystals consisting of calcium oxalate from a meta-stable solution may occur (so-called epitaxy). Frequently the existence of uric acid stones is without any symptoms. Modern views with regard to prophylactic procedures, diet, general and specific medical management including surgical intervention are presented.
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PMID:[Urate nephrolithiasis. Cause of consequence?]. 95 52

Experiments were carried out to study the effect of extracts from products of thermophilous methane fermentation at a dose of 0.7+2.0 ml/100 ml on the proliferation and fermentation activity of yeast Saccharomyces vini of the Yablochnaya-7 and Vishnevaya-33 race during their cultivation in the Hansen medium and in the apple and cranberry must with a normal and elevated content of sugar and acid. In some experiments the must was enriched in (NH4)2HPO4 at a dose of 0.3 g/l. Additions of small amounts of products of thermophilous methane fermentation accelerated fermentation of fruit musts with a normal sugar content and to a greater extent musts with an increased sugar content (27%). In the must enriched in (NH4)2HPO4 an almost complete (over 98%) fermentation of sugar developed for 27 days. In the must with an increased acidity (due to citric acid added to bring titrable acidity to 25 g/l) additions of the preparation also accerlerated the begining of the fermentation and increased its intensity.
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PMID:[Effect of products of thermophilous methane fermentation on the fermentation of fruit must by Saccharomyces vini]. 120 26

The study comprised a series of 16 neonates made up of 5 patients of 33 weeks of gestation, 5 infants of 35 weeks and 6 more of 40 weeks of gestation. Blood pH, PaCO2 and HCO3- were measured together with bicarbonate, ammonium, titrable acidity and hydrogen ions in urine before and after intravenous infusion of sodium bicarbonate. Before infusion of bicarbonate, titrable acidity, ammonium and net acidity in urine were higher in accordance with a greater gestational age. As the administration of bicarbonate elapsed, titrable acidity, ammonium and net acidity dropped with increase in concentration of bicarbonate. A hypothesis is set forth that the differences found in the factors evaluated in urine before administration of bicarbonate depend on the physiologic characteristics set in the newborn by gestational age.
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PMID:[Renal response to intravenous administration of sodium bicarbonate in newborn infants of different gestational ages]. 124 69

The effect of urine pH on plasma disposition of ampicillin sodium was evaluated. A single dose of 10 mg/kg of body weight was administered IV to Thoroughbreds with alkaline (pH greater than 8.0) or acidic (pH less than 4.5) urine. Urine alkalinity was achieved and maintained by oral administration of up to 400 mg of sodium bicarbonate/kg/d, and acidity was achieved and maintained by oral administration of up to 400 mg of ammonium chloride/kg/d. Ampicillin sodium was measured in the plasma of horses by use of an agar diffusion microbiological assay with Bacillus subtilis as the test organism. The plasma disposition kinetics of ampicillin sodium best fitted a 2-exponential decay pattern, and statistically significant differences were not evident in elimination half-life, area under the plasma concentration time curve, volume of distribution, or body clearance rate between horses with alkaline or acidic urine. Results indicate that changes in urine pH over a range encountered in clinically normal horses are unlikely to affect plasma pharmacokinetic variables of ampicillin sodium after IV administration of the drug.
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PMID:Effect of changes in urine pH on plasma pharmacokinetic variables of ampicillin sodium in horses. 132 42


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