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Biomedical subjects

D Jack

Publications and source records attributed to D Jack.

At least 55 records · Page 3Linked to original sources
PubMed1989

The challenge of drug discovery.

The Centre for Medicines Research initiated annual lectures in 1986 to provide regular overviews of some of the Centre's major areas of research interest. The 1988 lecture was given on July 6 at the Royal College of Physicians by Dr David Jack, C.B.E., D.Sc., F.R.S.E., who was until recently Research and Development Director of Glaxo Holdings, plc. His comments on drug discovery, based on long and successful research experiences, will we feel be of great interest to our readers. We are grateful to him and the Centre for Medicines Research for this written account of his lecture.

Animals↗
PubMed1985

Pharmacological basis for the induction of gastric carcinoid tumours in the rat by loxtidine, an insurmountable histamine H2-receptor blocking drug.

The very late occurrence of gastric carcinoids in a life-span carcinogenicity study with loxtidine in the rat might have resulted from continuous achlorhydria induced by this long-acting unsurmountable histamine H2-antagonist. The nature of the anti-secretory activity of loxtidine was compared with that of ranitidine on histamine-induced acid secretion in the perfused stomach preparation of the rat and in the rat isolated gastric mucosa preparation. Ranitidine and loxtidine had qualitatively different inhibitory effects on acid secretion, ranitidine being a competitive antagonist of histamine even at high concentrations, whereas the effect of loxtidine on both preparations was unsurmountable at relatively low concentrations. These results support the hypothesis that the late formation of gastric carcinoids in rats receiving loxtidine is a consequence of persistent achlorhydria caused by unsurmountable blockade of parietal cell H2-receptors.

Animals↗
PubMed1985

AH23848: a thromboxane receptor-blocking drug that can clarify the pathophysiologic role of thromboxane A2.

Despite numerous suggestions in the literature that thromboxane A2 is involved in a variety of occlusive vascular diseases, no definitive evidence is available. Arguments have been presented to support the view that such evidence can only come from clinical studies with a highly specific thromboxane receptor-blocking drug. We have now identified such a drug, AH23848, in our laboratories. Preliminary experiments with AH23848, ([1 alpha (Z), 2 beta,5 alpha]-(+/-)-7-[5-[[(1,1'-biphenyl)-4-yl]methoxy]-2-(4-morpholin yl)-3-oxocyclopentyl]-4-heptenoic acid), show that it is a potent, specific thromboxane receptor-blocking drug that is orally active and has a long duration of action. It should be a valuable tool in elucidating any physiologic or pathologic role of thromboxane A2.

Angina Pectoris↗
PubMed1983

Histamine H2-antagonists--past, present and future.

In this selective review of histamine H2-antagonists, we emphasize the significance of burimamide, the first specific H2-antagonist, in physiology and pharmacology and describe how its discovery led to the development of cimetidine as a new treatment of acid-aggravated disease of the alimentary tract. Developments since cimetidine, include ranitidine, which is a more potent, selectively acting H2-antagonist. A new series of H2-blockers with prolonged activity is discussed, and exemplified, particularly AH 23844. Its prolonged action and its unusual, apparently insurmountable, blocking action is explained in fundamental physicochemical terms.

Animals↗
PubMed1977

Pharmacological and certain chemical properties of AH 10407, an unusually short-acting, competitive neuromuscular blocking drug, and some related compounds.

1,1-Azobis[3-methyl-2-phenylbenzimidazolinium]dimethanesulphonate (AH 10407) has an ultrashort, competitive neuromuscular blocking action in the mouse, cat, dog, Cynamolgus monkey and cotton-eared marmoset. 2 AH 10407 is chemically unstable in bicarbonate-containing solutions and is degraded to inactive products. The half-life of AH 10407 in vitro in dog and human whole blood and in Krebs physiological solution is about 1.0 minute. In distilled water and in HCO-3-deficient Krebs solution AH 10407 is much more stable. Base catalyzed degradation is shown to be the prime determinant of the duration of action of the drug. 3 Some pharmacological properties of AH 11244 and AH 11056, close analogues of AH 10407, are briefly described and the duration of their neuromuscular blocking actions rationalized by reference to their chemical stabilities.

Animals↗