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Biomedical subjects

S Pollack

Publications and source records attributed to S Pollack.

At least 235 records · Page 13Linked to original sources

Comparison of oral propranolol and verapamil for combined systemic hypertension and angina pectoris. A placebo-controlled double-blind randomized crossover trial.

The relative efficacies of oral verapamil, a calcium-entry blocking drug, and propranolol, a beta-adrenergic blocking drug, were compared in 12 patients who had both stable angina pectoris and mild to moderate systemic hypertension, using a placebo-controlled, double-blind, randomized crossover protocol. Compared with placebo, both propranolol and verapamil decreased the frequency of anginal attacks and the number of nitroglycerin tablets consumed, and increased exercise duration and total work; there were no significant differences in the antianginal effect of the two drugs. Both verapamil and propranolol reduced the supine and standing systolic and diastolic blood pressure measured at rest; compared with propranolol, however, verapamil had greater effects on standing diastolic blood pressure (p less than 0.002). Resting heart rate was reduced from placebo baseline with large doses of both drugs; compared with verapamil, however, propranolol exerted greater effects on resting heart rate and rate-pressure product. Plasma renin activity was increased from placebo baseline with verapamil (p less than 0.05), but was reduced with propranolol (p less than 0.05); no significant change in plasma aldosterone was seen with either drug. Verapamil appears to be a safe and effective treatment alternative to propranolol for relieving anginal symptoms, improving exercise tolerance, and reducing elevated systemic blood pressure in patients with both angina pectoris and mild to moderate systemic hypertension.

Adrenergic beta-Antagonists↗

Comparative effects of abrupt withdrawal of propranolol and verapamil in angina pectoris.

The potential hazards of abrupt withdrawal of propranolol have been described in patients with angina pectoris; however, the effects of abrupt withdrawal from long-term therapy with verapamil have not previously been investigated. The comparative effects of withdrawal from long-term treatment with propranolol and verapamil were assessed in a placebo-controlled double-blind randomized crossover study of 20 patients received placebo for 2 weeks, then increasing doses of propranolol (60 to 320 mg/day) or verapamil (240 to 480 mg/day) for 3 weeks. Patients were then abruptly withdrawn from drug onto placebo for 1 week, followed by crossover to the other drug treatment and a second withdrawal period. All 20 patients were withdrawn from verapamil without evidence of a rebound increase in frequency of anginal attacks, blood pressure, heart rate, or rate-pressure product and without a rebound deterioration in exercise tolerance. In contrast, with propranolol withdrawal, 2 patients (with the highest baseline angina attack rate) had a severe exacerbation of their anginal syndrome and could not undergo formal exercise testing; the other 18 patients were withdrawn from propranolol without incident. Plasma catecholamines were increased during exercise compared with rest during all treatments; however, the levels of catecholamines during exercise were significantly higher with propranolol than with verapamil and placebo (p less than 0.05). Levels of exercise catecholamines returned to placebo baseline values after withdrawal of propranolol.

Angina Pectoris↗

Congenital prolongation of Q-T interval: a family study of three generations.

Three generations of a family with the Romano-Ward syndrome are described. Of all the affected members, only 1 was symptomatic, experiencing episodes of syncope proven to be due to polymorphous ventricular tachycardia (PMVT) induced by chlorimipramine treatment for depression. During treatment of an episode of PMVT with lidocaine, the patient developed the 'torsade de pointes' variant of ventricular tachycardia, which progressed to ventricular fibrillation and was successfully treated with electroversion. The hazards of treating these patients with commonly used drugs, the possible etiologies for the Romano-Ward syndrome and its mode of inheritance are discussed.

Aged↗

Plasmodium falciparum: inhibition of in vitro growth by desferrioxamine.

Infectious agents must acquire iron from their host to survive, and iron deficiency has been reported to protect against malaria in humans. We have tested the the susceptibility of Plasmodium falciparum to iron deprivation by studying the effect of desferrioxamine (DF), a specific iron chelating agent, on parasite growth in an in vitro culture system. We have found that DF inhibits the growth of P. falciparum at concentrations readily achievable in vivo, by a mechanism that may involve interference with the completion of schizogony.

Deferoxamine↗

Pellagra as the presenting manifestation of Crohn's disease.

An 18-yr-old woman hospitalized with classical signs of pellagra was found to have Crohn's disease of the small and large bowel as well as malabsorption of nicotinic acid and iron. The symptoms of pellagra disappeared after intramuscular treatment with nicotinic acid, while the malabsorption was corrected following steroid therapy for the Crohn's disease. Pellagra should thus be added to the list of complications of Crohn's disease that are secondary to malabsorption. Although this complication seems to be very rare, it may be worthwhile to check for nicotinic acid malabsorption in untreated cases of Crohn's disease in order to determine its real prevalence.

Adolescent↗

Early events in guinea pig reticulocyte iron uptake.

Hemolysates, prepared from guinea pig reticulocytes incubated with 59Fe-labelled serum, can be resolved into five peaks utilizing molecular sieve chromatography: ferritin, transferrin, hemoglobin, an Mx 17 000 fraction, and a low molecular weight fraction. The hemoglobin peak also contains a nonhemoglobin component (III-X), demonstrated by heme extraction and by isoelectric focusing. Transferrin, the III-X component and the low molecular weight fraction are the first to accumulate radioactive iron during the reticulocyte incubation. The 59Fe in each of these also chases. Therefore, a role for these components as precursors to iron incorporation into heme is suggested.

Animals↗

Synergistic effect of nitrilotriacetate on iron mobilization by desferrioxamine in vivo.

Removal of iron from biologically important ligands by desferrioxamine (DF), in vitro, is exceedingly slow because of a kinetic barrier. This kinetic barrier can be overcome by a variety of a small molecular weight anions, of which nitrilotriacetate (NTA) is a prototype. We explored the effect of NTA on DF iron mobilization in vivo. Iron mobilization was increased and the effect was synergistic.

Acetates↗

Antibiotic-responsive malabsorption: a tropical sprue-like syndrome in countries with temperate climates.

Antibiotic-responsive malabsorption is prevalent in the tropics, but has been seen only sporadically in countries with temperate climates. We describe a 19-year-old Israeli patient who has never left the country and was hospitalized with shigellosis and malabsorption of fat and D-xylose. A short course of ampicillin reversed the malabsorption. The syndrome of antibiotic-responsive malabsorption in countries with temperate climates may well be underdiagnosed and should be looked for more actively.

Adult↗

Cholestatic jaundice caused by cloxacillin: macrophage inhibition factor test in preventing rechallenge with hepatotoxic drugs.

Severe intrahepatic cholestasis occurred in a patient after taking nitrofurantoin, ampicillin, and cloxacillin. As only nitrofurantoin was known to cause cholestasis she was given cloxacillin again two years later. The cholestasis reappeared at once. A macrophage inhibition factor test confirmed that cloxacillin was the offending drug. Cloxacillin should be added to the growing list of drugs causing cholestasis. Inadvertent rechallenge with hepatototoxic drugs might be prevented by routine use of the macrophage inhibition factor test.

Aged↗

Subacute bacterial endocarditis.

Two patients in whom various immunological phenomena obscured and delayed the diagnosis of subacute bacterial endocarditis (SBE) are described. Immunological abnormalities usually correlate well with the chronicity and severity of the disease, as is demonstrated here. The mechanisms underlying the various immunological phenomena are discussed. The importance of alertness to the possibility of SBE in cases of disease manifesting itself as an immunological disorder, thus achieving early diagnosis and early antimicrobial treatment, is stressed.

Adult↗

Cutaneous pigmentation: a probable sign of spontaneous bacterial peritonitis.

A cirrhotic patient with ascites was apparently well managed with diuretics and salt and water restriction for 9 months. A spontaneous bacterial peritonitis (SBP) developed and the patient finally died following septic shock. There were enough findings indicating that SBP in this case had been existing silently for some time. During this period the only apparent manifestation of this complication was a cutaneous pigmentation on the abdomen. It is suggested that pigmentation may be incuded among other presentations of this frequently silent process.

Aged↗