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Biomedical subjects

S Pollack

Publications and source records attributed to S Pollack.

At least 217 records · Page 12Linked to original sources
PubMed1985

Guinea pig and human red cell hemolysates release iron from transferrin.

Despite a binding constant of 10(22) L/mol-1, iron is released from transferrin in the reticulocyte. The mechanism of this release is unclear. It has been suggested that iron is released from transferrin in endocytic vesicles that have been acidified. But the carboxy-terminal iron in transferrin is acid stable at the pH apparently achieved in the endocytic vesicle, and is, nevertheless, released. We found that red cell hemolysates, at neutral pH, will release iron from transferrin. With molecular sieve chromatography, the activity is seen to consist of high and low molecular weight components. The activity of both components is susceptible to destruction by phosphatases. The releasing activity of hemolysates can account for about 25% of the iron uptake of a reticulocyte at pH 7; at pH 5.5 (the purported pH of the endocytic vesicle), the releasing activity is sufficient to account for all the iron taken by the reticulocyte.

Animals↗
PubMed1985

Psychotropic drugs and long QT syndromes: case reports.

Two depressed patients with long QT syndrome who experienced torsade de pointes ventricular tachycardia when treated with psychotropic drugs are discussed. These cases emphasize the significance of electrocardiographic evaluation of depressed patients, particularly in patients who show evidence of a long QT interval.

Aged↗
PubMed1984

Neisseria subflava endocarditis. Case report and review of the literature.

Neisseria subflava is a rare cause of bacterial endocarditis. Only seven cases have been identified in the world literature if strict criteria as to organism classification and of endocarditis are applied to individual case reports. The first reported case in an intravenous drug user is described. In addition, findings on serial two-dimensional and M-mode echocardiography performed during and after the treatment period are presented. This patient's recovery with anti-microbial therapy alone despite evidence of aortic and significant mitral valve involvement is in accord with results of other antibiotic-treated cases.

Adult↗
PubMed1984

Plasmodium falciparum takes up iron from transferrin.

Plasmodium falciparum, cultured in vitro, is inhibited by desferrioxamine, a specific iron chelating agent, despite the abundant haem iron which surrounds the parasite. In this report we show that the intraerythrocytic parasite obtains iron from transferrin. The parasite may therefore be freed of a requirement to catabolize haem to obtain iron thus minimizing haem toxicity.

Animals↗
PubMed1984

Susceptibilities of bacterial and fungal urinary tract isolates to desferrioxamine.

Desferrioxamine, a safe and effective iron chelator, was evaluated for its antibacterial and antifungal activity. The susceptibilities of 124 urinary tract isolates and 28 clinical isolates of Neisseria gonorrhoeae to desferrioxamine concentrations that are readily achievable in urine were determined. Of all isolates, 27% were inhibited by a concentration of less than or equal to 12.5 mM. Proteus mirabilis and N. gonorrhoeae isolates were particularly susceptible to the chelator. Desferrioxamine appears to have limited potential as an antibacterial agent.

Anti-Bacterial Agents↗
PubMed1984

Cholestatic jaundice induced by gold salts treatment clinical and immunological aspects--report of one case and review of the literature.

Hepatotoxicity is a rare complication of treatment with gold salts. The clinical and laboratory features are those of cholestatic jaundice and other diagnostic possibilities must be ruled out. Gradual recovery after withdrawal of the drug is the rule. We report a case and review previous literature with emphasis on the diagnostic value of the lymphocyte transformation test.

Arthritis, Rheumatoid↗
PubMed1983

Endotoxin-induced in vitro release of interleukin-1 by cancer patients' monocytes: relation to stage of disease.

The in vitro release of IL-1 by monocytes in response to endotoxin was subnormal in many patients with breast cancer, malignant melanoma or colorectal cancer but not in patients with benign tumors of the breast or colon. In each of these groups, IL-1 release was low in patients with early cancer, normal in patients with regional metastases, and low in patients with disseminated cancer.

Adult↗
PubMed1983

Malaria and iron.

Explore the source record for details and available documents.

Deferoxamine↗
PubMed1983

Human pleuropulmonary gnathostomiasis: a case report from Israel.

We report a case of human gnathostomiasis presenting with bilateral pleural effusion and probable pericardial involvement. The diagnosis was made on the basis of the patient's country of origin (Nepal), the course of the disease, marked eosinophilia and the identification of Gnathostoma in a thoracic skin biopsy. The patient responded, presumably, to treatment with diethylcarbamazine (Hetrazan). This case is unique in its presentation and occurrence in Israel (although not necessarily acquired in Israel).

Adult↗
PubMed1982

Deletion of active human suppressor T lymphocytes from peripheral blood by Sephadex G-10 filtration.

A method for antigen-specific generation of antibody-forming B cells in cultures of human peripheral blood mononuclear (PBM) cells based on the Mishell-Dutton system has recently been established in this laboratory. Comparing PBM cell cultures from healthy donors and from patients with advanced cancer we found the latter to be unresponsive in our assay. Passage of PBM cell suspension over Sephadex G-10 columns restored the response of patient PBM cells to normal levels. The cell population trapped on the column can be recovered and its inhibitory potential demonstrated by its graded addition to cells eluted from the column. The cell responsible for inhibition is sensitive to treatment with OKT8 antibody and complement, indicating its T cell nature. Passage of PBM cells from healthy individuals did not alter antibody responses substantially but made the activation requirements less stringent.

Animals↗
PubMed1982

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↗
PubMed1982

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↗
PubMed1982

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↗