Eugene D. Jacobson

Comparison of Prostaglandin E1 and Norepinephrine on the Gastric Mucosal Circulation

Summary Secretion, mucosal blood flow, and the ratio (R) of blood flow to secretory rate were measured in conscious dogs provided with a gastric fistula. Secretion was stimulated to steady rates about one third of maximal with either pentagastrin or histamine. Prostaglandin E1 (PGE1) or norepinephrine was administered in doses of 0.1 or 1.0 μg kg-1 min-1. With the high dose of either agent, secretion was decreased, whether stimulated by histamine or pentagastrin, but the ratio of blood flow to secretory rate was decreased only with norepinephrine. It is concluded that norepinephrine operates to reduce secretion by limiting mucosal blood flow. On the other hand, PGE1, which is a powerful vasodilator, reduces secretion by a primary mechanism other than restricting gastric mucosal blood flow. The decrease in blood flow seen with PGE1 appears to be the result and not the cause of gastric secretory inhibition. I am indebted to Drs. Morton I. Grossman and Andre Robert for their critical comments and suggestions, to Dr. John McCoy of the Southwest Research Support Center for statistical and computational assistance, and to Mr. Alvin C. K. Chang and Mrs. Tulin Oruc for technical support. These investigations were supported by a grant from the U. S. Public Health Service (N.I.H., AM 11073-04). The PGE1 used in this study was supplied by Dr. John Pike (Upjohn).

Effects of ouabain on splanchnic hemodynamics in the rhesus monkey

Abstract : When the effects of ouabain on splanchnic hemodynamics of the anesthetized monkey are evaluated, the major events were found to be a decrease in mesenteric blood flow and an increase in mesenteric vascular resistance. Implications of these findings are that use of cardiac glycosides may be contraindicated in clinical states characterized by low blood flow to the splanchnic region. (Author)

Altered Vascular Responsiveness: Initial Hypotensive Mechanism of Thiazide Diuretics

Conclusion In order to separate electrolyte and intravascular volume mechanisms of the thiazide diuretics from hemodynamic, local vascular, and neural factors mongrel dogs were studied before and 20 min after chlorothiazide (25 mg/kg, iv). Dose-response relationships of the mean arterial pressure curve following single bolus injections of norepinephrine and angiotensin were also obtained before and after chlorothiazide. Serum electrolytes, hematocrit, and plasma protein concentrations remained unchanged. Arterial pressure did not change, whereas cardiac output fell (p < .001). At each dose level the integrated pressure response to both pressor agents became significantly attenuated. These data indicate that the major immediate effect of the thiazide is local alteration in vascular responsiveness. Later, with natriuresis, electrolytic, volume, and possibly neural factors also participate. The authors gratefully acknowledge the fine technical assistance of Mr. Alan Chang and Mrs. Janice Pfeffer and the secretarial work of Mrs. Irene Smith.

Intestinal Vascular Responses to Gut Pressure and Acetylcholine in vitro

Active and passive elevation of intraluminal pressure in the denervated gut was studied to determine the effect on blood flow. In an in vitro preparation of canine intestinal segments, the vessels wer

Effects of Distension and Acetylcholine on Intestinal Blood Flow in vivo

In vivo canine gut segments perfused by branches of the superior mesenteric artery were subjected to increased intraluminal pressure to observe the effects upon arterial inflow, measured with an electromagnetic blood flowmeter, and venous effluent collected by a cannula. Inflation of the intestinal segment with air simultaneously reduced both inflow and outflow. Intra-arterial infusion of acetylcholine increased blood flow, even with intraluminal pressure maintained at 40 mm Hg. Mechanical distension of the gut impedes blood flow, but this effect can be overridden by a vasodilator. These findings correspond to results observed in similar experiments on in vitro gut segments.

Fluid Dynamics in Volumogenic Diarrhea

A study was performed to evaluate motility patterns and the role of intestinal sphincters in a diarrhea model. Fluid was infused into the canine duodenum to produce diarrhea. We discerned 4 patterns o

Comparison of Early Hemodynamic Phenomena in Three Forms of Shock in Dogs

Summary Response patterns of arterial pressure, cardiac output, venous return, and total peripheral resistance were determined in 3 lethal shock states. Hemorrhagic shock decreased pressure and flows most profoundly and most persistently but increased resistance. Endotoxic shock caused an initial transient decrease in pressure and flows, followed by a later depression of these measurements and also decreased total peripheral resistance. Cardiogenic shock gradually decreased pressure and flows and did not change resistance. The concept of a single early circulatory derangement as the primary cause of irreversibility in shock is not supported by our findings.

Blood Flow and Gastrointestinal Diseases

Aberrations in gastrointestinal blood flow are associated with several gastrointestinal disorders. In peptic ulcer, intestinal obstruction, and ulcerative colitis, the circulatory abnormalities appare