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Biomedical subjects

V B Subramanian

Publications and source records attributed to V B Subramanian.

27 records · Page 2Linked to original sources
PubMed1982

Randomized double-blind comparison of verapamil and nifedipine in chronic stable angina.

A randomized double-blind crossover trial was performed in 32 patients with chronic stable angina to compare the antianginal actions of verapamil (120 mg 3 times daily) and nifedipine (20 mg 3 times daily). Efficacy was assessed using objective end points obtained by computer-assisted exercise testing and 24 hour ambulatory monitoring for S-T segment shift. Twenty-eight patients completed the trial. The mean exercise time to produce angina improved from 5.7 +/- 0.3 minutes (mean +/- standard error of the mean) in patients on placebo, to 7.9 +/- 0.5 minutes in those on nifedipine and 10.0 +/- 0.7 minutes in those on verapamil. Similar improvement was seen in all other objective variables. Generally verapamil produced mild bradycardia and nifedipine mild tachycardia. Four patients complained of palpitations and angina after ingestion of nifedipine and were identified by ambulatory monitoring to have tachycardia and persistent S-T depression. These opposite effects on heart rate may explain the differences in efficacy between these 2 potent calcium ion antagonists.

Adult↗
PubMed1982

The 24-hour ambulatory blood pressure profile with verapamil.

The blood pressure response in hypertensive subjects to chronic treatment with verapamil, a calcium antagonist (or, more precisely, a slow-channel inhibitor), was studied using the Oxford system for continuous monitoring of intraarterial blood pressure. Sixteen patients underwent continuous monitoring over a 48-hour period before and after at least 6 weeks of therapy (dose range 120-160 mg three times daily). Each monitoring period included physiologic tests designed to show the effects of different types of exercise. Verapamil produces a consistent reduction of blood pressure over 24 hours, but particularly during the day. Heart rate was similarly reduced. There was no evidence of postural hypotension, and the absolute responses to dynamic and isometric exercise were reduced. The degree of reduction of the blood pressure was consistent, suggesting that slow-channel inhibitors may be appropriate for antihypertensive therapy.

Adult↗
PubMed1980

Verapamil in chronic stable angina. A controlled study with computerized multistage treadmill exercise.

The efficacy of verapamil (360 mg daily) in the treatment of patients with chronic stable angina pectoris was compared with placebo. 28 patients were studied in a placebo-controlled double-blind crossover trial of 2 weeks each and afterwards on long-term verapamil. Exercise tests were performed at the end f the placebo period, and after 2 weeks and 4 weeks on verapamil. On placebo, angina developed in all 28 patients during treadmill tests; the mean exercise time was 6.6 min (SEM +/- 0.5 min). The mean exercise time increased to 9.2 (+/- 0.8) min at 2 weeks, and 11.2 (+/- 0.8) min at 4 weeks on verapamil. In 15 and 20 patients out of the 28 angina did not develop during treadmill exercise at 2 and 4 weeks respectively. Trinitrin consumption also decreased. There was a significant improvement in ST-segment changes. Constipation (in 7 patients) and reversible PR-interval prolongation (in 2 patients) were the only side effects. No patient had clinical signs of heart-failure. Thus verapamil (360 mg daily) may be useful in the management of chronic stable angina.

Adult↗
PubMedDate not supplied

The C3b/C4b receptor (CR1, CD35) on erythrocytes: methods for study of the polymorphisms.

This report is devoted to methodologies used in analyzing the C3b/C4b receptor (CR1, CD35) on erythrocytes (E), its soluble form, the CRI structural or allotype polymorphism, and CR1 density polymorphism. In primates E CR1 serves as the main system for processing and clearance of complement opsonized immune complexes (IC). CR1 copy numbers decrease with aging of E in normal individuals. Erythrocyte CR1 is also decreased in pathological conditions such as systemic lupus erythematosus (SLE), HIV infection, certain hemolytic anemias, and many other conditions featuring immune complexes. Consequently, CRI on E has an important physiological role in immune complex handling and has interesting alterations in disease.

Animals↗
PubMedDate not supplied

Nifedipine or verapamil as sole treatment of hypertension. An intraarterial study.

Intraarterial ambulatory blood pressures were recorded prior to and during therapy with two different calcium ion antagonists, nifedipine and verapamil, in two separate groups of patients. In the first group, nine patients were studied off therapy and following a minimum of 6 weeks of nifedipine treatment (dose range, 20 to 60 mg twice daily). A second group of 16 patients followed the identical protocol but were prescribed verapamil (120 to 160 mg, three times daily). During both studies, patients underwent standardized physiological tests including tilt, isometric handgrip, and dynamic bicycle exercise. Both verapamil and nifedipine caused a reduction in blood pressure over most of the 24 hours studied. Nifedipine did not affect heart rate whereas verapamil caused a reduction of approximately 10 bpm. Nifedipine and verapamil did not induce postural hypotension, and the absolute responses to dynamic and isometric exercise were reduced. These results show the efficacy of slow channel inhibitors in the management of essential hypertension.

Adult↗