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Biomedical subjects

C Zoccali

Publications and source records attributed to C Zoccali.

At least 109 records · Page 6Linked to original sources
PubMed1985

Effect of naloxone on the defective autonomic control of heart rate in uraemic patients.

The role of endogenous opioids on the reflex cardiovascular control of chronic uraemic patients was investigated. The opiate antagonist naloxone administered intravenously caused a significant increase in the abnormal Valsalva manoeuvre ratio in nine chronic uraemic patients, but it had no effect in six diabetic patients with normal renal function, whose response to the Valsalva manoeuvre was similar to that of chronic uraemic patients. Naloxone had no effect in eight normal subjects. The increase in the Valsalva ratio observed in uraemic patients was due to restoration of the parasympathetically mediated reflex bradycardia of the release phase of the manoeuvre. Naloxone did not modify supine and standing blood pressure and heart rate in any group. Endogenous opioids may be involved in the defective autonomic control of heart rate in uraemic patients.

Adult↗
PubMed1985

Effects of potassium on sodium balance, renin, noradrenaline and arterial pressure.

To determine the effects of potassium on blood pressure and factors affecting blood pressure, we conducted a randomized, placebo controlled trial of a potassium chloride-based substitute for table salt in 23 patients with mild to moderate essential hypertension. In addition, the effects of potassium chloride on sodium balance were studied in 10 normal subjects. Potassium loading with 100 mmol/day over five days in these normal subjects caused a cumulative negative sodium balance of 138 +/- 35 mmol, similar in degree to that achieved by severe dietary sodium restriction. However, two weeks of potassium treatment (100 mmol/day) in patients with essential hypertension did not lower blood pressure (BP) either in the supine or upright positions (potassium treatment: mean BP 108 +/- 3 lying and 113 +/- 3 mmHg standing; placebo treatment: mean BP 109 +/- 3 lying and 115 +/- 3 mmHg standing). Patients found it difficult to tolerate the potassium-based salt substitute in the dose given. We conclude that it is premature to recommend an increase in potassium chloride intake as treatment for raised blood pressure.

Adult↗
PubMed1985

Hyperchloraemia: a non-specific finding in chronic renal failure.

To determine the prevalence of hyperchloraemia (plasma chloride concentration of 107 mmol/l or above) in chronic renal failure (CRF), we retrospectively analysed the acid-base and electrolyte status of 102 Italian and 53 English patients with impaired renal function. Hyperchloraemia was a frequent finding at all stages of CRF with a prevalence ranging from 30 to 50%. It was common both in tubulointerstitial nephropathies (45%) and chronic glomerulonephritis (39%). Hyperchloraemic patients were more acidotic than the normochloraemic.

Acid-Base Equilibrium↗
PubMed1985

The role of endogenous opioids in the baroreflex dysfunction of dialysis patients.

We studied the effect of the opiate antagonist naloxone on the response to Valsalva manoeuvre in nine dialysis patients, in six diabetics with normal renal function whose response to Valsalva manoeuvre was similar to that of dialysis patients and in eight healthy subjects. Naloxone caused a progressive increase in the subnormal Valsalva ratio in dialysis patients but it did not cause any change in diabetics nor in healthy subjects. The increase in Valsalva ratio observed in dialysis patients was due to restoration of the parasympathetically mediated reflex bradycardia of the release phase of the manoeuvre. Endogenous opioids may be responsible for the baroreflex dysfunction of dialysis patients.

Adult↗
PubMed1985

Influence of blood temperature on vascular stability during hemodialysis and isolated ultrafiltration.

We tested the hypothesis that differing temperature (T) changes in extracorporeal blood circuit might partly account for the difference in vascular stability (VS) between isolated ultrafiltration (UF) and simultaneous UF-hemodialysis (HD). The study was carried out in 6 patients who presented frequent episodes of symptomatic hypotension during the routine dialytic sessions. During simultaneous UF-HD with dialysate T set at 37.5 degrees C (standard HD), blood reentered the patients with a T of about 2 degrees C higher, whereas during isolated UF (standard UF) 2 degrees C lower, than at its exit. These extracorporeal blood T changes were reciprocated by warming the venous line in isolated UF (warm UF) and by setting the dialysate at 34.5 degrees C in simultaneous UF-HD (cold HD). During warm UF mean arterial pressure (MAP) fell and heart rate (HR) increased nearly as much as during standard HD. Vice versa, during cold HD MAP and HR remained nearly as stable as during standard UF. It is concluded that the T changes in blood flowing through the extracorporeal circuit largely account for the differing VS between isolated UF and simultaneous UF-HD.

Adult↗
PubMed1984

Relation of blood pressure and body sodium content during sodium depletion in normal and hypertensive subjects.

Blood pressure, exchangeable sodium content, sodium metabolic balance, and plasma concentrations of active renin, angiotensin II, and aldosterone were measured in seven normal men and 10 essential hypertensive men of similar age and weight. The measurements were made under two circumstances: during a 2- to 3-day period of normal sodium intake of 145-150 mmol/24 h and during a 2- to 3-day period of sodium depletion produced by 40 mg frusemide and a dietary sodium intake less than 10 mmol/24 h. Mean arterial pressure decreased in nine of the 10 hypertensive subjects but increased in six of the seven normotensive subjects during sodium depletion. Blood pressure changed more for a given change in exchangeable sodium level in hypertensive subjects than in normotensive subjects, despite a similar loss of sodium in the two groups. Changes in blood pressure varied markedly in the hypertensive group. Patients showing the greatest fall in arterial pressure had the least rise in plasma active renin concentration and, not significantly, the least rise in plasma aldosterone level. These findings are compatible with a model of pressure natriuresis which is altered more in normal subjects during changes in dietary sodium content, thereby preventing a rise in arterial pressure. Failure of this compensatory mechanism in hypertensive subjects may raise blood pressure.

Adult↗
PubMed1984

Enalapril (MK421) and its lysine analogue (MK521): a comparison of acute and chronic effects on blood pressure, renin-angiotensin system and sodium excretion in normal man.

The immediate and long-term effects of enalapril (MK421) and its lysine analogue (MK521) in once-daily dosage, were compared in a study of 12 normal subjects. Both compounds lowered blood pressure equally throughout 24 h without causing tachycardia. The biochemical changes with MK521 were more sustained than with MK421, but this did not affect the magnitude of blood pressure reduction. Twenty-four hours after the previous dose, with both active drugs, plasma renin concentration was significantly higher on day 8 than on day 1, though angiotensin I did not increase in proportion; this probably reflects a fall in renin-substrate with prolonged converting enzyme inhibition. There was an early natriuresis with each compound but this effect was no longer apparent after 8 days of continuous therapy. Both MK421 and MK521 were well tolerated with no serious side effects.

Adult↗
PubMed1984

Effect of the 5-hydroxytryptamine type 2 receptor antagonist, ketanserin, on blood pressure, the renin-angiotensin system and sympatho-adrenal function in patients with essential hypertension.

Ketanserin, a 5-HT type 2 receptor antagonist, was administered intravenously to nine patients with essential hypertension in a double-blind placebo controlled study to investigate the drug's effects on blood pressure, heart rate, the renin-angiotensin system and sympatho-adrenal function. Average blood-pressure for the group prior to injection of the drug was 150 +/- 7/94 +/- 4 (s.e. mean) mm Hg and decreased significantly (P less than 0.01) to 137 +/- 8/88 +/- 5 mm Hg during the 2 h after injection; heart rate increased immediately after injection of ketanserin, reaching a maximum of 81 +/- 4 beats/min. After drug administration systolic and diastolic blood pressure decreased on tilting, but the heart rate response was not different from that with placebo. Ketanserin did not affect the blood pressure response to graded infusion of the alpha 1-adrenoceptor agonist phenylephrine. Plasma active renin, angiotensin II and aldosterone concentrations increased slightly but not significantly after the drug; plasma noradrenaline increased transiently. 5-HT may be important in the maintenance of blood pressure but alternative mechanisms for the action of ketanserin in reducing blood pressure require investigation.

Adrenal Glands↗
PubMed1983

The effect of a 5-HT antagonist, ketanserin, on blood pressure, the renin-angiotensin system and sympathoadrenal function in normal man.

The role of endogenous 5-hydroxytryptamine (5-HT) in the control of blood pressure, the renin-angiotensin system and sympatho-adrenal function was investigated in normal man. Ketanserin (a specific 5-HT2 antagonist) administered intravenously caused a small decrease in blood pressure in salt-depleted recumbent subjects. A more marked postural fall in pressure occurred in both sodium-depleted and repleted normal subjects. Plasma active renin concentration and angiotensin II increased after administration of ketanserin, but plasma aldosterone, cortisol and noradrenaline were unchanged. 5-HT may be important in the control of blood pressure in man and specific 5-HT2 receptor antagonists could be a useful new class of antihypertensive agents.

Adrenal Glands↗
PubMed1983

10. Hypertension. A comparison of the effects of angiotensin II infusion and variations in salt intake on plasma aldosterone levels in normal subjects, patients with essential hypertension and patients with hyperaldosteronism.

Infusion of angiotensin II into a patient with dexamethasone-suppressible hyperaldosteronism caused a brisk increase in plasma aldosterone concentration. In this behaviour, the patient resembled those patients with idiopathic hyperaldosteronism rather than those with tumorous primary hyperaldosteronism. Sodium depletion of a small group of patients with mild essential hypertension elicited a spectrum of increases in plasma aldosterone levels ranging from zero to normal. Angiotensin II infusion in both sodium replete and deplete states also caused variable aldosterone responses. These results suggest that the derangement of adrenal function in this condition varies continuously in severity.

Adrenocorticotropic Hormone↗
PubMed1983

Blood temperature and cardiovascular stability in hemofiltration.

Temperature (T) changes in the blood flowing through the extracorporeal circuit markedly affect cardiovascular tolerance to fluid removal during either hemodialysis (HD) and isolated ultrafiltration. In this study we investigated the effect of blood T changes during postdilutional hemofiltration (HF). To this purpose we compared the changes in mean arterial pressure (MAP) and heart rate (HR) during HF and HD carried out at equivalent T of blood in the venous segment of the extracorporeal circuit. Results show that HF entails some heat loss from blood flowing in the extracorporeal circuit; if heat loss is made similar, HD affords nearly as much blood pressure protection as HF does. On the other hand at equivalent heat gain, HF causes nearly as much hypotension as HD does. We conclude that blood T changes in the extracorporeal circuit affect vascular stability (VS) even in HF. The marginal benefit of HF over HD, still observed at equalized T changes, remains to be elucidated.

Blood↗
PubMed1982

Defective reflex control of heart rate in dialysis patients: evidence for an afferent autonomic lesion.

1. To localize the site of autonomic abnormality in patients undergoing haemodialysis, tests of overall autonomic function based on either changes in blood pressure (posture, sustained handgrip) or heart rate (Valsalva manoeuvre, 30 : 15 ratio, deep breathing test) were used. Integrity of the sympathetic efferent arc was examined by using the cold pressor test and the parasympathetic efferent arc by the atropine test. Eighteen patients and 12 control subjects were studied. 2. Changes in blood pressure in standing, sustained handgrip and in the cold pressor test were the same in the two groups. 3. In contrast, 11 patients had abnormal results in at least two of the three heart-rate-based tests. 4. Three of the 11 dialysis patients with evidence of autonomic involvement showed abnormal responses to atropine, indicating an efferent parasympathetic lesion, whereas the majority had a normal response to the atropine test, suggesting an afferent lesion only. 5. Evidence of autonomic involvement was not associated with hypertension nor confined to patients with dialysis hypotension.

Adult↗
PubMed1982

Effect of furosemide on renal size: ultrasonic characterization of renovascular hypertension.

In this pilot study, sequential ultrasonic scanning was used to assess (a) whether furosemide injection normally causes an enlargement of kidney size, and (b) whether this effect is blunted in renovascular hypertensives to such a degree as to bear potential diagnostic value. Furosemide caused similar degrees of maximal area enlargement in both kidneys of 10 healthy subjects (16.1 +/- 3.9%) and 10 essential hypertensives (14.8 +/- 4.2%) whereas in 11 renovascular patients maximal distension of the affected kidneys was significantly blunted (9.4 +/- 3.7%) in comparison with that of contralateral kidneys (19.6 +/- 7.7%). In the 6 hypertensives with one small kidney not due to renal artery stenosis, maximal enlargement of the affected kidneys averaged 22.8 +/- 5.1%, and that of contralateral kidneys 15.8 +/- 4.2%. In 8 out of the 11 patients with renovascular hypertension the difference in response between the paired kidneys had values outside the ranges of patients with both the other forms of arterial hypertension. The data suggest that the furosemide test may be of value in the screening for renovascular hypertension.

Adult↗
PubMed1982

Effect of chronic propranolol treatment on bone changes of secondary hyperparathyroidism in dialysis patients.

To assess the effect of long-term propranolol therapy on uremic osteodystrophy, we evaluated retrospectively the biochemical, X-ray, and bone histological changes in 9 dialysed hypertensives who had been on propranolol treatment for periods ranging from 1 to 8 years. The control group included 9 well-matched dialysed uremics never treated with beta-blockers. The two groups did not differ in serum ionized calcium or iPTH levels. The incidence of bone resorption evaluated on X-ray findings and on bone biopsy specimens was of a comparable degree in the two groups. Our data show that propranolol even if started early in the course of renal failure, is of no benefit in preventing uremic bone disease.

Bone Resorption↗
PubMed1981

Light-chain nephropathy in patient with renal carcinoma.

Paraneoplastic syndromes are often associated with renal parenchymal tumours. This report describes a case of renal-cell carcinoma with kappa-chain nephropathy. The patient, a 60-year-old man, had renal tubular dysfunction, shown by low serum concentrations of urate and phosphate. Kappa-chains were found in both serum and urine, but no lambda-chains were found. Investigations showed a clear-cell carcinoma, and the patient underwent a radical nephrectomy. Two years after operation serum phosphate and urate concentrations had returned to normal, and kappa-chains were undetectable in serum or urine. The absence of lambda-chains indicates that the light-chain proteinuria was due to overproduction of the M component, and the disappearance of kappa-chains after the operation suggests a causal relation between the renal tumour and the overproduction of the M component.

Adenocarcinoma↗