Effect of captopril in Bartter's syndrome.
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Bartter Syndrome↗
Biomedical subjects
P Boer
Publications and source records attributed to P Boer.
Blood and extracellular fluid volume in patients with Bartter's syndrome.
Blood and extracellular fluid volumes were measured in four adult patients with Bartter's syndrome and compared with those of 21 healthy control subjects. Extracellular fluid volumes were significantly lower than in the control group (-7%), whereas blood volumes were within the normal range. Consequently, the ratio of blood volume to interstitial fluid volume was significantly elevated (0.42 v normal 0.35). The results are consistent with the concept that a tubular reabsorption defect is present in Bartter's syndrome.
Adolescent↗
Changes in the glycoprotein composition of plasma membrane during the differentiation of friend erythroleukemia cells.
Friend erythroleukemia cells display transient and permanent changes in the composition of their plasma membrane-bound glycoproteins during dimethyl sulfoxide-induced differentiation. The transient changes, as revealed by metabolic labeling with [14C]glucosamine, are most conspicuous around the time during which most cells become committed to terminal differentiation. Permanent changes are revealed by reductive tritiation after oxidation with NaIO4 or galactose oxidase. In differentiated cells one glycoprotein fraction (Mr 150 000) could not be labeled by any of these methods, although it does contain neuraminic acid. We found no evidence in support of the hypothesis that the anomalous behavior of this fraction is caused by an increased degree of O-acetylated neuraminic acid in the plasma membrane of differentiated cells.
Animals↗
Long-term treatment of bartter's syndrome with captopril.
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Adult↗
Effects of fructose on synthesis and degradation of purine nucleotides in isolated rat hepatocytes.
The effects of fructose on purine nucleotide synthesis and degradation were studied in isolated rat hepatocytes. Incubation of the hepatocytes with fructose resulted in deceleration of the rate of de novo purine synthesis, gauged by the rate of incorporation of precusor [14C]formate into total purines produced, and in acceleration of purine nucleotide degradation, as measured by the rate of conversion of prelabelled purine nucleotides into end-product allantoin. These effects were found to be associated with decreases in cellular content of ATP and Pi and in the metabolic availability of 5-phosphoribosyl 1-pyrophosphate. The results support the suggestion that the fructose-induced acceleration of purine degradation is mediated through activation of AMP deaminase. However, the results also suggest that decreased reutilization of hypoxanthine for IMP synthesis, due to the decreased PP-Rib-P availability, is an additional mechanism for the acceleration of purine degradation. The decreased PP-Rib-P availability is also suggested to be the main mechanism for the fructose-induced deceleration of purine synthesis.
Animals↗
Inhibitors of protein glycosylation inhibit the differentiation of Friend erythroleukemia cells.
Tunicamycin, 2-deoxy-D-glucose and 2-deoxy-2-fluoro-D-glucose inhibit dimethyl sulfoxide-induced differentiation of Friend cells. This inhibition, characterized by inhibition of hemoglobin synthesis, is accompanied by a specific inhibition of protein glycosylation. The results of cloning experiments indicate that this inhibition specifically affects cells in the period preceding their commitment. These results suggest that glycoprotein synthesis is a requirement for Friend erythroleukemia cells in order to initiate the expression of the terminal differentiation program.
Animals↗
De novo purine synthesis in skeletal muscle.
Myoblast and primary muscle cultures from rat were found to contain the complete pathway of de novo purine nucleotide synthesis. Quantitative assessment of the pathway in skeletal muscle in mice in vivo, revealed a more intensive purine production in muscle than in liver. Skeletal muscle is thus a major site of de novo purine production in the mammalian body.
Animals↗
Plasma aldosterone concentrations in chronic renal disease.
The disagreement in the literature concerning the role of aldosterone in the maintenance of potassium homeostasis in chronic renal disease might be partially explained by differences in plasma renin activity (PRA) among individual patients. Therefore, a study was done in 28 selected patients with varying degrees of renal insufficiency whose serum potassium and PRA concentrations were within the normal range. The results indicate that at comparable serum potassium and PRA concentrations, plasma aldosterone is in most instances elevated when creatinine clearance is lower than 50% of normal.
Adult↗
Renal clearance of [14C]oxalate: comparison of constant-infusion with single-injection techniques.
1. The renal clearance of [14C]oxalate was assessed by the constant-infusion technique and single-injection technique (plasma sampling only: one-compartment and two-compartment model; plasma and urine sampling). Healthy volunteers and patients with renal stones were studied. 2. Results with the constant-infusion techniques (with and without urine sampling) were not significantly different from each other. 3. The renal clearance of [14C]oxalate measured with the single-injection technique as compared with the constant-infusion technique was overestimated in the single-injection one-compartment model (52%) as well as in the two-compartment model (30%). 4. The calculated level of plasma oxalate in the healthy volunteers ranged from 1.04 to 1.78 mumol/l (mean 1.39). 5. The biological half-life of [14C]oxalate, estimated by the cumulative excretion of 14C in urine after equilibrium had been established, was 128 min (range: 113-142). 6. The oxalate/creatinine clearance ratio in the healthy volunteers ranged from 1.73 to 2.22 (mean 2.01).
Female↗
Changes in intrarenal uric acid handling during chronic spironolactone treatment in patients with essential hypertension.
Intrarenal handling of uric acid was studied in 12 patients with essential hypertension under spironolactone treatment (200 mg/day). The degree of volume depletion during treatment was assessed from the changes in body weight and plasma renin activity (PRA). The results are compared with those in patients treated with chlorthalidone (50 mg/day). During spironolactone treatment, the serum uric acid level remained constant despite a progressive volume depletion which after 3 months reached levels identical to those achieved in the chlorthalidone-treated patients, whose serum uric acid level showed the expected rise (21%). The uric acid excretion during spironolactone treatment was markedly diminished (-28%), and thus the 24-hour clearance of uric acid was correspondingly decreased (-22%). It is concluded that spironolactone affects uric acid metabolism in two ways: it causes a decrease in uric acid renal clearance (probably mediated by the induced volume depletion and PRA elevation, as with other saluretics) and, probably, inhibits endogenous uric acid production to approximately the same degree as the clearance is decreased, so that no change in the serum uric acid level occurs. The purpose of the study was to investigate the effect of spironolactone on uric acid handling by the kidney. We found a decrease in uric acid clearance and uric acid excretion. Serum uric acid concentration did not change.
Body Weight↗
Free water excretion due to suppressed vasopressin and stimulated aldosterone during sodium restriction in hypoaldosteronemic renal failure.
In two from 3 hyperkalemic patients with chronic glomerulonephritis associated with suppressed aldosterone production ("selective hypoaldosteronism") fractional free water excretion increased and urine osmolality decreased during sodium (Na) restriction. In one of the patients with severe renal concentrating defect in combination with partial vasopressin deficiency polyuria was paradoxically accentuated by lowered Na intake. Na restriction induced 1. a dramatic increase in plasma aldosterone levels, 2. a decrease in glomerular filtration rate associated with a marked disturbance in the glomerulotubular balance resembling to the effects of volume expansion, and 3. a decrease in urinary arginine vasopressin excretion. Paradoxical enhancement of water excretion was explained by increased delivery of filtrate into the distal nephron, increased abstraction of Na from the tubular fluid together with insufficient water permeability of the collecting tubules and lowered vasopressin production.
Adolescent↗
Salt handling in patients with chronic renal insufficiency.
In 7 patients with moderate degrees of renal insufficiency the effect of high and low salt intake on renal NaCl handling was investigated by means of clearance techniques. After a steady state had been reached at low (1 g NaCl daily) and high (10 mmol NaCl daily for every ml X min-1 glomerular filtration rate) salt intake, proximal and distal fractional salt reabsorption (FSRprox and FSRdist) were estimated, maximal free water clearance being taken as an index of distal NaCl reabsorption. Mean FSRprox during low salt intake was 86.7% (range 80-90%) of the filtered load, and decreased to 77.9% (range 70.1-80.5%) during high salt intake. The water-loading procedure in these patients resulted in enhanced NaCl and nonelectrolyte solute excretion, especially during salt restriction. This made certain corrections obligatory for the proper calculation of FSRdist. Mean FSRdist during low salt intake was 96.5% (range 93.1-99.8%) of distal delivery, and decreased to 76.0% (range 68.0-82.1%) during high salt intake. This decrease of FSRdist also existed at comparable levels of distal delivery. It is concluded that renal response to chronic sodium loading in patients with chronic renal insufficiency is similar to that as in normal men, and consists of reduction of both proximal and distal fractional NaCl reabsorption.
Absorption↗
[The role of prostaglandins in the pathogenesis of Bartter's syndrome].
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Adult↗
Determination of glomerular filtration rate by 111In-DTPA.
To evaluate the use of 111indium-diethylenetriamine pentaacetic acid (111In-DTPA) for determination of the glomerular filtration rate (GFR), the results of 60 standard 111In-DTPA clearances were compared with 24-h urine endogenic creatinine clearances obtained on 3 successive days (r = 0.97, P less than 0.001) and with endogenic creatinine clearances obtained during 111In-DTPA determinations (r = 0.93, P less than 0.0001). It is concluded that 111In-DTPA is a useful marker for GFR.
Creatinine↗
Haemodynamic and hormonal changes during acute and chronic diuretic treatment in essential hypertension.
The short- and long-term effects of diuretic treatment with chlorthalidone 50 mg/day on haemodynamic and hormonal parameters in patients with essential hypertension (WHO grade I) were investigated. After three days of treatment, all patients showed a rise in plasma renin activity (PRA), plasma aldosterone (PA), urinary norepinephrine excretion (UNE) and heart rate (HR), and a decrease in body weight (BW) and extracellular volume (ECV) and blood volume (BV); the change in blood pressure (BP) was variable. The changes in BP were correlated with those in BV. After three months of therapy, the signs of volume depletion tended to fade, but the lower ECV persisted. In contrast to the 4-day study, after three months the change in BP correlated inversely with changes in ECV and renin dependency (saralasin response), and positively with PRA and changes in UNE. It is concluded that the BP response to diuretic treatment is determined by the adaptation with time of the haemodynamic reactions to the volume-depleted state. Whether this adaptation will take place cannot be predicted from the control values of the parameters studied, or from acute changes observed during the first days of treatment.
Adolescent↗
Changes in intrarenal sodium handling during saluretic treatment in patients with essential hypertension.
The effect of 50 mg chlorthalidone on blood pressure, body fluid volumes and renal functional parameters was determined in 8 patients with essential hypertension. After 3 days there were signs of volume depletion with little change in mean arterial pressure (MAP). Maximal free water clearance (CH2O) was decreased and fractional proximal sodium reabsorption was increased, but no correlations between these parameters were found. After 3 months there was in inverse relationship between both changes in MAP and the indices of volume depletion and CH2O. It is concluded that when MAP decreases after prolonged saluretic treatment, there is a partial recovery of the initially induced volume depletion and less stimulation of proximal tubular sodium reabsorption. The continuing inhibitory action of chlorthalidone on "distal" sodium reabsorption is partially compensated for, probably by the stimulating effect at this site of the decrease in MAP.
Adolescent↗
Determination of oxalic acid clearance and plasma concentration by radioisotope infusion. Results in a family with hyperoxaluria.
The renal clearance of 14C-oxalate was studied in a family with two children suffering from primary hyperoxaluria. The 14C-oxalate/creatinine clearance ratio ranged from 1.8 to 2.6 (mean 2.0) and appeared to be independent of the glomerular filtration rate. The calculated plasma oxalate concentrations in the three normo-oxaluric subjects ranged from 0.1 to 0.9 mumol/l, whereas values of 3.2 and 16.3 mumul/l were found in the two hyperoxaluric subjects. In the latter patient, the oxalate production decreased and the clearance increased after vitamin B6 treatment, resulting in a drop in the oxalate plasma level to 5.3 mumol/l. The apparent distribution volumes, expressed as percentage of body weight, ranged from 30 to 47% (mean 35). The mean biological half-life of 14C-oxalate was 2.7 hours in the subjects with normal renal function and increased with impairment of renal function. The recovery of 14C in the urine ranged from 87 to 112% (mean 101); all 14C activity was recovered as oxalate.
Adolescent↗
Peripheral beta-adrenoceptor responsiveness in young normotensive and hypertensive subjects.
In young subjects with normal blood pressure (N = 10) or with mild (n = 6) or moderate (n = 8) hypertension we assessed the effects of increasing doses of i.v. isoproterenol (each dose for 10 min) on systolic and diastolic blood pressure, heart rate, plasma renin activity (PRA), serum potassium and free fatty acids (FFA). Except for blood pressure, basal levels did not differ significantly between the groups. Isoproterenol induced dose-related increases in systolic blood pressure, heart rate and PRA, and dose-related decreases in diastolic blood pressure. Neither the threshold dose (i.e. the lowest dose significantly affecting these parameters), nor the changes induced by the higher doses differed between the normotensive and hypertensive subjects. Levels of serum potassium and FFA, obtained at the end of the infusion, also did not differ significantly between the groups. These results indicate, that in contrast to older and/or more severely hypertensive subjects, young subjects with mild to moderate hypertension have a peripheral beta-adrenoceptor responsiveness similar to that of normotensive controls.
Adult↗