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Biomedical subjects

J R Zabludowski

Publications and source records attributed to J R Zabludowski.

11 recordsLinked to original sources
PubMed1994

Effects of residual renal function in haemodialysis patients.

Thirty-six haemodialysis patients on treatment for more than six months were studied for residual renal function (RRF). Twenty patients were anuric. The remaining 16 patients with RRF excreted 35-1600 ml urine/day with creatinine clearance ranging 0.17-6.95 ml/min. Patients with RRF were on dialysis therapy for shorter periods than those with anuria (25.5 +/- 18.5 vs. 101.7 +/- 14.2 months, p = 0.001). Twelve out of 20 anuric patients had had previous renal transplantation, whereas none of those with RRF had been transplanted (p = 0.0006). Interdialytic weight gain, serum potassium and phosphate were lower in patients with RRF. Serum phosphate and uric acid were correlated with their respective urinary excretion rates (p = 0.013 and 0.005, respectively), but interdialytic weight gain could not be correlated with urinary output. Creatinine clearance significantly correlated with urinary excretion of potassium, sodium, phosphate and uric acid. In this series of patients a previous unsuccessful renal transplantation was an important factor in the loss of RRF. The presence of RRF contributed to the regulation of the blood levels of phosphate and the excretion rate of potassium, sodium and uric acid.

Blood Urea Nitrogen↗
PubMed1992

Overdiagnosis of hypertension in the elderly.

Seventeen untreated and 36 treated hypertensives aged 65 years or more were referred to our clinic because of repeated values of systolic blood pressure > or = 160 mmHg and diastolic blood pressure > or = 95 mmHg. All 53 patients underwent 24h blood pressure monitoring during their customary daily activities. Eleven (65%) untreated and 23 (64%) treated patients were normotensive during their daily activities. Thus, ambulatory BP monitoring appears to be useful in the elderly hypertensive patients in detecting those whose BP is elevated only in the clinic. Ambulatory BP obtained outside the clinic may be useful in diagnostic and therapeutic decision-making in the elderly population.

Aged↗
PubMed1992

Causes of death in patients with end-stage renal disease treated by dialysis in a center in Israel.

The causes of death in 84 end-stage renal failure patients, treated with dialysis, who died during a 66-month period were reviewed retrospectively. Cardiac and infectious diseases were the main cause of death (27% each). These two constituted 44% of causes of death in hemodialysis and 75% in continuous ambulatory peritoneal dialysis patients. Malignant disease (7%) and hyperkalemia (5%) were responsible for death only in hemodialysis patients. Patients who died following hyperkalemia were younger than 50 years old. Patients who died from malignant disease were dialyzed for more than 3 years. In summary, the mode of dialysis therapy, age at start of therapy, time on dialysis, and previous cardiac disease may play a role in determining the causes of death in dialysis patients.

Adolescent↗
PubMed1992

Evaluation of clinic blood pressure measurements: assessment by daytime ambulatory blood pressure monitoring.

The clinical value of a set of three clinical blood pressure measurements as a predictor of daytime ambulatory hypertension was assessed by performing a set of clinical blood pressure measurements in 171 borderline hypertensives, and calculating their diagnostic accuracy, sensitivity, specificity and predictive value compared to the daytime average of ambulatory blood pressure monitoring. Diagnostic accuracy was 0.63, sensitivity was 81% and specificity was 47%. Positive and negative predictive values were 0.60 and 0.74, respectively. The set of clinical measurements detected 81% of hypertensives, but 36% of the population screened was mislabelled--48 patients (28%) as hypertensive and 15 (8%) as normotensive. A single set of clinic blood pressure measurements is quite sensitive for diagnosing daytime hypertension, although its accuracy, specificity and predictive value are low. The subpopulation incorrectly labelled as normotensive may have a different prognosis and merits further prospective study.

Ambulatory Care↗
PubMed1985

Ketanserin and alpha 1-adrenergic antagonism in humans.

Ketanserin has been shown to antagonise both alpha 1-adrenergic (alpha 1) and 5-HT2-serotonergic (5-HT2) receptors in animal experiments but the findings in humans have been conflicting. Its mode of action in reducing blood pressure is unclear. We have studied, therefore, the effects of ketanserin 40 mg b.i.d. given orally for 4 days to seven normal volunteers on blood pressure, heart rate, and tests of baroreflex function, including infusion of the alpha 1-adrenergic agonist, phenylephrine. Ketanserin caused a small reduction in both lying and standing blood pressure after 4 days but with no change in heart rate; no subject had a severe fall in pressure after the first dose. The 30:15 and Valsalva manoeuvre ratios were decreased slightly. The dose-response curve of blood pressure against rate of phenylephrine infusion was shifted to the right in keeping with alpha 1-adrenergic antagonism; the degree of shift was small compared with that after prazosin. The relationship between change in blood pressure and heart rate during phenylephrine infusion was not affected by ketanserin. Ketanserin may act as an alpha 1-adrenergic antagonist. The development of more selective agents to antagonise 5-HT2-serotonergic receptors should clarify the role of this aspect of the drug's action in reducing blood pressure.

Adrenergic alpha-Antagonists↗
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↗