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Biomedical subjects

F Salnitro

Publications and source records attributed to F Salnitro.

9 recordsLinked to original sources
PubMed1992

The influence of autonomic failure on plasma ANF concentration in uremic patients on chronic hemodialysis.

We compared plasma ANF concentration in 5 diabetic-uremics with combined sympathetic-parasympathetic dysfunction with that in 9 uremic patients without autonomic impairment. Symptomatic dialysis hypotension was a major clinical problem in all diabetic-uremics. In the volume-expanded state, ANF was almost twice as high (p less than 0.025) in diabetic-uremics than in control uremics (152 +/- 29 vs 84 +/- 10 pg/ml) in the face of similar right atrial pressure (14 +/- 3 vs 12 +/- 1 cm H2O). After isolated ultrafiltration, ANF fell significantly in both groups remaining slightly (NS) higher in diabetic-uremics. The slope of the relationship between ANF and right atrial pressure was significantly (p less than 0.01) steeper in diabetic-uremics than in control uremics. The data indicate that autonomic failure amplifies the effect of atrial stretching on plasma ANF in diabetic-uremics on chronic hemodialysis treatment.

Adult↗
PubMed1991

Hyperfiltration and calcium metabolism in essential hypertension.

To test the hypothesis that hyperfiltration in essential hypertension is linked to alterations in calcium metabolism, we studied the relationship between urinary calcium excretion and glomerular filtration rate (GFR, creatinine clearance) in 38 untreated essential hypertensives on a free diet. We also studied the influence of changes in calcium intake on GFR in 30 essential hypertensives (15 with well-defined hypercalciuria and 15 with normal urinary calcium excretion) and in 11 normotensive healthy subjects. In the patients on a free diet, urinary calcium excretion was directly and independently related to GFR (r = 0.56, P less than .001), while serum calcium showed an opposite trend (r = -0.27, P = .12). In patients on fixed calcium diets, GFR was significantly higher (P = .008) at low calcium intake (115 +/- 31 mL/min/1.73 m2) than at high calcium intake (98 +/- 22 mL/min/1.73 m2). Further analysis showed that the hyperfiltering effect of low calcium almost exclusively occurred in hypercalciuric patients and in hypertensive women. In hypercalciuric hypertensives there was a highly significant inverse correlation between GFR and serum calcium (r = -0.51, P = .004) and a similar correlation between GFR and plasma renin activity (r = -0.70, P = .003) in the high calcium phase of the study. Changes in calcium intake had no influence on GFR in normal subjects (Low Ca 103 +/- 22 mL/min/1.73 M2, High Ca 110 +/- 23 mL/min/1.73 m2). The data indicate that alterations in calcium metabolism interfere to an important extent with mechanism(s) regulating GFR in essential hypertension.

Adult↗
PubMed1991

The reflex control of vasopressin in haemodialysis patients.

We studied the reflex arginine vasopressin (AVP) response to hypotensive, isosmotic fluid subtraction (by isolated UF) in 14 uraemic patients on renal dialysis treatment: five with normal autonomic function and nine with autonomic involvement of various degrees. Fluid subtraction caused a comparable mean arterial pressure (MAP) decrease in the two groups. The reduction in right atrial pressure was inversely related with the severity of autonomic neuropathy (rs = -0.72, P = 0.004), being distinctly attenuated in the second group (P = 0.006). Plasma arginine vasopressin increased similarly in patients with normal autonomic function and in those with autonomic involvement. The response of patients with haemodialysis hypotension was similar to that of other patients. Reflex control of arginine vasopressin is preserved even in the presence of afferent/central neuropathy or more advanced, widespread autonomic damage in uraemic man. The data suggest that it is unlikely that altered release of arginine vasopressin is involved in the pathogenesis of haemodialysis hypotension.

Adult↗
PubMed1991

Mechanism of hypercalciuria in essential hypertension and in primary nephrolithiasis.

We have studied the metabolic response to changes in calcium in 15 hypercalciuric essential hypertensives, in 8 normotensive hypercalciuric stone formers and in 11 normotensive healthy subjects matched for age and sex. At variance with hypercalciuric stone formers, at low calcium intake hypercalciuric hypertensives did not appropriately reduce urinary calcium excretion and developed mild hypocalcemia. Furthermore, the PTH response to calcium deprivation was not appropriately enhanced in these patients. The data indicate that different mechanisms prevail in these two forms of hypercalciuria: the renal in essential hypertension and the intestinal in urolithiasis.

Adult↗
PubMed1990

Complement activated leucopenia during hemodialysis: effect of pulse methyl-prednisolone.

We tested in vivo the effect of methyl-prednisolone (MP) on C5a release and granulocytopenia occurring early in the course of extracorporeal blood circulation through a Cuprophan dialyzer. MP boluses (30 mg/kg) were given to 10 consenting patients suffering from acute renal failure, immediately before blood started to circulate through a hollow-fiber Cuprophan dialyzer. To avoid drug loss through the dialyzer membrane, dialysate flow was withheld during the first hour of treatment and ultrafiltration was kept near zero (sham dialysis). Control procedures were carried out in a similar way, without MP. MP concentration, differential WBC count and anaphylotoxin C5a were serially measured during the procedures. MP pharmacokinetics was evaluated in six other uremic patients off dialysis. As shown by similar C5a levels in dialyzer effluent blood, complement cascade was activated by Cuprophan to a comparable degree whether or not patients received MP. Neutrophil count dropped 68% during the control procedure and 54% during sham dialysis preceded by MP (95% confidence interval of the difference, 1.97-27.2). Sham dialysis did not apparently influence serum MP levels, as shown by similar peak values in patients undergoing sham dialysis (203 micrograms/ml +/- SEM 33) and in patients off dialysis (177 micrograms/ml +/- 42). In vitro aggregometry showed that the uremic milieu does not interfere with the antiaggregating effect of MP. Our results show that MP at the dosage of 30 mg/kg does not affect complement-mediated granulocytopenia in any important way.

Acute Kidney Injury↗
PubMed1989

The 'breakpoint' test, a new statistical method for studying progression of chronic renal failure.

The application of a new statistical method ('breakpoint' test) to the study of the progression of chronic renal failure is described. This test establishes whether the best fit of a series of GFR measurements is linear or broken. Such an approach avoids the analytical constraint of the time of intervention assumed by other methods. Re-analysis by this test of previous studies of low-protein diet suggests that in some cases the effect of the dietary regimen has been overemphasized.

Creatinine↗
PubMed1986

Effect of ultrafiltration on plasma concentrations of atrial natriuretic peptide in haemodialysis patients.

We have investigated the influence of body fluid volume status on plasma levels of immunoreactive atrial natriuretic peptide (irANP) in eight uraemic patients on chronic haemodialysis, including two diabetics with severely impaired reflex control of the heart. IrANP was significantly higher in volume-expanded uraemic patients (36 +/- 16 pg/ml) than in a group of seven age and sex-matched normal subjects (14 +/- 2 pg/ml), and fell consistently, approaching the normal range after the removal of 2.0-4.3 litres of isotonic plasma ultrafiltrate (by isolated ultrafiltration). Plasma levels of the hormone were strictly related to right atrial pressure. The irANP response to ultrafiltration in the two diabetics was similar to that of the other uraemic patients. The results suggest that the elevated irANP levels found in volume-expanded uraemic patients depend largely on fluid overload per se. The preserved irANP response to ultrafiltration of the two diabetics with severe autonomic neuropathy indicates that in chronic renal failure irANP secretion may be regulated independently from autonomic influences.

Adult↗