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Biomedical subjects

C Chaimovitz

Publications and source records attributed to C Chaimovitz.

At least 73 records · Page 4Linked to original sources
PubMed1982

Pathogenesis of salt retention in dogs with chronic bile-duct ligation.

1. The present study investigates the role of mineralocorticoids in the pathogenesis of salt retention and ascites in dogs with chronic ligation of the common bile duct (CBDL). 2. After CBDL the natriuretic response to an intravenous sodium load [0.9% sodium chloride solution (150 mmol/l): saline; 10% of body weight] was markedly depressed. Urinary sodium excretion was 285 +/- 62 vs 960 +/- 58 mumol/min in the control period before CBDL (P less than 0.001). This antinatriuresis was associated with a significant rise in plasma aldosterone concentration, from 52.5 +/- 5.5 pg/ml before CBDL to 177 +/- 50 pg/ml after CBDL (P less than 0.02). Ascites was present in all salt-retaining CBDL dogs. 3. Bilateral adrenalectomy resulted in disappearance of ascites and in a rise in the natriuretic response to extracellular volume expansion. Urinary sodium excretion was 770 +/- 124 mumol/min, a value significantly higher than in the CBDL dogs with intact adrenals (P less than 0.001). Sodium balance studies in the adrenalectomized CBDL dogs during chronic deoxycorticosterone acetate (DOCA) treatment (25 mg/day) showed that in these animals there was failure to escape from the mineralocorticoid-induced sodium retention. Glomerular filtration rate and renal plasma flow did not change during the studies. 4. The present evidence supports the thesis that sodium retention in the CBDL dog results from a dual mechanism: (a) excess of circulating aldosterone and (b) and extra-adrenal factor which prevents escape from the salt-retaining effect of mineralocorticoids, in the CBDL dogs, thereby perpetuating the antinatriuresis in these animals.

Adrenalectomy↗
PubMed1982

Role of vasopressin in abnormal water excretion in cirrhotic patients.

Twelve stable cirrhotic patients with ascites received a 20 mL/kg water load. Seven patients had abnormal water excretion (27.3% +/- 5.4% of the water load in 5 hours) and a minimal urine osmolality of 262 mosmol/kg water. Five patients excreted 82.6% in 5 hours and had a minimal urine osmolality of 65 mosmol/kg water. Mean plasma arginine vasopressin values after water load were significantly higher in Group 1 (1.34 +/- 0.36 pg/mL) than in Group 2 (undetectable). An effective blood volume lower in Group 1 than Group 2 patients was suggested by a lower plasma albumin (2.5 versus 3.3 g/dL, p less than 0.02), a higher pulse rate (96 versus 72, p less than 0.001), a higher plasma renin activity (7.8 versus 1.5 ng/mL . h, p less than 0.005), a higher plasma aldosterone (66 versus 21 ng/dL, p less than 0.05), and a lower urinary sodium excretion (2.7 versus 14.2 meq Na/5 h, p less than 0.005). The results suggest that nonosmotic stimulation of vasopressin secondary to a decrease in effective blood volume is an important factor in the abnormal water excretion of cirrhosis.

Adult↗
PubMed1982

Tubular handling of sodium following immersion to the neck and salt-induced volume expansion.

We wished to compare the natriuretic and diuretic effect of extracellular volume expansion (ECVE) with 0.9% NaCl to that obtained with up-to-the-neck immersion (NI) in healthy volunteers. Clearance techniques during maximal antidiuretic hormone suppression were utilized to pinpoint the sites of tubular NaCl reabsorption. Mean glomerular filtration rate (GFR) did not differ significantly between ECVE and NI; mean rate of sodium excretion during ECVE was significantly greater than during NI, whereas mean water clearance for a given rate of distal delivery was higher with NI than with ECVE. Our findings suggest that ECVE is associated with greater natriuresis than NI, despite the equality of filtered sodium loads and of distal deliveries under both these procedures.

Adult↗
PubMed1982

Serum amyloid A (SAA) in viral infection: rubella, measles and subacute sclerosing panencephalitis (SSPE).

Serum amyloid A (SAA) levels were determined in the serial serum samples of eight rubella, 10 measles and seven subacute sclerosing panencephalitis (SSPE) patients. An early rise in SAA levels was detected in the acute phase in rubella and measles, followed by a prompt decrease in the convalescent phase. In a number of measles and rubella patients from whom early serum samples were available, the rise of SAA levels could be demonstrated before specific viral antibodies could be detected by complement fixation (CF) (measles) and haemagglutination inhibition (HI) (rubella). In only one rubella and one measles patient was no rise of SAA level detected. In SSPE only a moderate increase in SAA levels was noted except in one patient during a temporary deterioration, at which time the SAA level was very high; it returned to close to normal shortly thereafter. The possibility that SAA levels might be of value in monitoring the severity of infections, the recovery process and effects of anti-viral agents is discussed.

Adult↗
PubMed1980

Effect of indomethacin in a patient with Bartter's syndrome: evidence against a primary role of prostaglandin in this disorder.

It has been claimed that in patients with Bartter's syndrome, enhanced prostaglandin synthesis causes the blunted vasopressor response to angiotensin II. The present study was undertaken to test this hypothesis by administering indomethacin to a patient with Bartter's syndrome. In domethacin corrected the subnormal pressor response to angiotensin II and lowered plasma renin activity from 115 to 15 ng/ml/hr. This effect was associated with renal sodium retention and a 7% increase in body weight. In contrast, when indomethacin was given but the sodium retention prevented by concomitant administration of furosemide, the blunted vasopressor response to angiotensin II and the hyperreninemia were not corrected. It is concluded that the effectiveness of indomethacin to correct the hyperreninemia and the blunted vasopressor to angiotensin II in the preset patient was due in large part to the ability of the drug to correct sodium balance rather than by inhibition of prostaglandin synthesis.

Adolescent↗
PubMed1979

Lithium-induced nephrogenic diabetes insipidus: studies of tubular function and pathogenesis.

We describe a patient with lithium-induced nephrogenic diabetes insipidus in whom detailed investigations of distal tubular function were performed. Clearance of free water during water diuresis was found to be augmented. This suggests proximal suppression of sodium reabsorption by lithium. Reabsorption of free water during high solute clearance was impaired. Acidification of the urine following ammonium chloride loading was abnormal, and this was corrected by sodium sulfate infusion. The cellular mechanism of lithium was investigated by means of indomethacin, an inhibitor of prostaglandin synthesis. Indomethacin caused a partial reversal of the nephrogenic diabetes insipidus, suggesting that the primary cellular action of lithium may be to inhibit the formation of cyclic AMP in the collecting duct cell, although a direct action of indomethacin in increasing solutes in the renal medulla could not be ruled out. It is possible that the lithium-induced polyuria is partially due to an enhancement by lithium of renal prostaglandin action.

Ammonia↗
PubMed1978

Defective high-density lipoprotein composition in patients on chronic hemodialysis. A possible mechanism for accelerated atherosclerosis.

We determined serum high-density lipoprotein cholesterol content and analyzed the approtein structure of the various lipoprotein fractions in 21 patients on chronic hemodialysis. High-density lipoprotein cholesterol was significantly reduced in all patients as compared with 11 normal persons (mean +/-1 standard deviation: 26 +/- 13 vs. 52 +/- 9 mg per 100 ml; P less than 0.001) whether or not triglyceride levels were raised. In seven of those with Type IV hyperlipoproteinemia, protein content of high-density lipoprotein and its subfractions 1, 2 and 3 were also reduced (P less than 0.001) in parallel with reductions in cholesterol in these fractions. Apoprotein electrophoresis showed an increase in "arginine-rich" peptide in very-low-density lipoprotein and high-density lipoprotein fraction 1, and a reduction in apoprotein Cll in very-low-density and high-density lipoprotein. In addition to their reduced high-density lipoprotein cholesterol levels, a major factor in the atherosclerosis of these patients may be their abnormal high-density lipoprotein composition. Their raised triglyceride levels could be due to defective lipoprotein lipase activation by the reduced very-low-density lipoprotein apoprotein.

Adolescent↗
PubMed1978

The effect of acute extracellular volume expansion on sodium chloride reabsorption in the diluting segment in man.

1. The effect of extracellular volume expansion (ECVE) during water diuresis, and of water diuresis alone, on the formation of free water in man was compared. 2. ECVE reduced free water formation at any given rate of distal delivery compared with water diuresis. Thus, ECVE depresses distal sodium chloride reabsorption. 3. This attenuation of free water formation occurred both when urine flow (V/100 ml glomerular filtration rate) and distal chloride delivery [(Cwater + Ccl)/100 ml glomerular filtration rate] were used as the terms for distal delivery. 4. We suggest that the distal depression of sodium chloride reabsorption after ECVE is robably due to a direct inhibition of distal sodium chloride transport mechanisms, and not to the flooding of the diluting site by the poorly reabsorbable bicarbonate ion.

Absorption↗