Search PubMed⌕ Search

Biomedical subjects

H L Dhar

Publications and source records attributed to H L Dhar.

30 records · Page 2Linked to original sources

Captopril--nifedipine interaction in hypertension.

Nifedipine, a calcium channel blocker exerts significant peripheral vasodilatory activity in hypertensive patients. It has been postulated that the antihypertensive effect of peripherally acting vasodilators is masked, by counter regulatory mechanism e.g. activation of renin-angiotensin aldosterone (RAA) axis. The present work was undertaken to study the effect of blockade of RAA axis using captopril, an angiotensin converting enzyme inhibitor on the blood pressure lowering activity of nifedipine. Pretreatment with captopril in a dose of 25 mg. bd was carried out for 4 weeks in one group of 10 patients before administering nifedipine 10 mg bd for 4 weeks. The other matched group of 10 patients received nifedipine alone in the same dose. It was observed that although captopril by itself had no appreciable effect on blood pressure in the dose used, it significantly enhanced the blood pressure lowering activity of nifedipine. It appears that counterregulatory mechanisms play an important role in determining the net antihypertensive effect of peripheral vasodilators.

Adult↗

Role of cholinergic mechanism in the hypoglycemic action of B. pertussis vaccine.

The present work aims to study the role of the cholinergic mechanism in the hypoglycemic action of B. pertussis vaccine in rats. The vaccine resembles insulin in that the hypoglycemia produced is mainly due to the increase conversion of glucose to glycogen in the liver and muscle. Both the hypoglycemia as well as glycogen deposition was partially blocked by atropine. On the other hand the vaccine potentiated the fall in the blood sugar and deposition of glycogen in the tissues produced by physostigmine. This suggests the possible involvement of the cholinergic system in the hypoglycemic action of the vaccine.

Animals↗

Effect of Bordetella pertussis vaccine on bleeding time, whole blood coagulation time and platelet aggregation in animals.

Bordetella pertussis vaccine, a hypoglycemic agent significantly prolonged the bleeding time and whole blood coaguistion time in rabbits and dogs when administered intraperitonially. The vaccine also affects platelet aggregation in rats 4 days after its intraperitonial administration. The effect on platelet aggregation is thought to be due to its beta adrenargic receptor blocking action which may also contribute to the hypoglycemia.

Animals↗

The insulin-like action of Bordetella pertussis vaccine in rats.

Treatment of rats with Bordetella pertussis vaccine significantly lowered the blood sugar level 4 days later but the vaccine did not alter the level in diabetic rats. The vaccine, like insulin, raised glycogen levels in liver, skeletal muscle and heart and reduced the plasma free fatty acid concentration. The action of a beta-adrenoceptor blocker was potentiated by the vaccine but not by insulin. Part of the hypoglycaemic action of the vaccine is probably due to beta-adrenoceptor blockade.

Adrenergic beta-Antagonists↗

Sugar polymers in rats and man.

Intracutaneous injections of a glucan contaminant of invert sugar solutions and crude cane sugar into human skin produced a localised wheal and erythema reaction. The glucan was also active on intradermal injection into both dextran-sensitive and dextran-resistant rats.

Animals↗

Relative bioactivity of histamine and slow reacting substance of anaphylaxis released during anaphylactic reaction from different tissues of guinea pigs and rats.

Relative amount of histamine and SRS-A released during Schultz Dale reaction were indirectly estimated. Percent block produced by specific antagonists, mepyramine and FPL 55712, on antigen induced response in various tissues was compared with controls. The relative bioactivity of histamine and SRS-A released was 93% and 7%, respectively, in rat lungs: 37% and 63% in guinea pig lungs; 82% and 18% in guinea pig intestine, 59% and 41% in rat intestine and 100% and 0% in skin of guinea pig and rats. Expectedly, individual experiments showed gross variations because anaphylaxis is rarely dose related.

Anaphylaxis↗