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Biomedical subjects

O Lundgren

Publications and source records attributed to O Lundgren.

At least 181 records · Page 10Linked to original sources
PubMed1976

The intestinal mucosal lesions in shock. II. The relationship between the mucosal lesions and the cardiovascular derangement following regional shock.

The relationship between the mucosal lesions in the gut, observed after a 2-hour period of regional hypotension, and the blood pressure fall seen after the hypotensive period was investigated in cats. Untreated controls were compared to animals treated with intraluminal perfusion with nitrogenated or oxygenated saline or treated with intraluminal instillation of albumin, activated charcoal or aprotinin or i.v. injections of methylprednisolone. Untreated controls and cats perfused with nitrogenated saline exhibited a pronounced reduction in arterial blood pressure during the first posthypotensive hour. In the animals treated with methylprednisolone or perfused intraluminally with oxygenated saline only a small fall of blood pressure was observed. In the remaining groups of animals a moderate blood pressure reduction was noted. These results suggest a causal relationship between the intestinal mucosal damage and the posthypotensive cardiovascular derangement possibly via the release of cardiotoxic material from the hypoxic intestinal villi.

Albumins↗
PubMed1976

Effects on myocardial contractility of blood-borne material released from the feline small intestine in simulated shock.

There is a pronounced derangement in cardiovascular function in the cat after a 2- or 3-hour period during which shock is simulated in the small intestine by regional hypotension (BP = 30-35 mm Hg) during activation of vasoconstrictor nerve fibers. It has been proposed that these effects are caused by blood-borne cardiode-pressant substance(s) released from the "shocked" small intestine. To obtain further evidence for this hypothesis we performed a study on two heart preparations in vitro. Rabbit papillary muscles or isolated beating rat hearts were exposed to intestinal venous plasma obtained from control cats and from cats subjected to simulated intestinal shock for 2 or 3 hours. while control plasma induced only a slight depression of myocardial contractility, plasma from "shocked" intestine caused a significant decrease in peak isometric tension of the papillary muscles or a fall in systolic pressure of the rat hearts. Since the experiments on papillary muscle indicated that time to peak tension was largely unaffected by the plasma samples, we conclude that the feline intestine in shock releases material into blood that exerts a negative inotropic effect on the myocardium.

Animals↗
PubMed1976

Colonic blood flow in cat and man as analyzed by an inert gas washout technique.

An inert gas elimination technique for studying blood flow and flow distribution in the colon was developed on the cat and applied to patients during abdominal surgery. The method involves recording of the elimination of intra-arterially injected 85Kr from a colonic segment whereby the gamma- and beta-radiation of the tracer is registered simultaneously by a scintillation detector and Geiger-Muller tube, respectively. Total blood flow was determined from the recording of gamma-radioactivity using a modification of Zierler's formula, and muscularis blood flow as calculated according to Kety from the mono-exponential elimination recorded by the Geiger-Muller tube. The relative weights of the muscularis and mucosa-submucosa were determined from dissections or histological sections. With these weights and total and muscularis blood flows, flow in the mucosa-submucosa was calculated. Total colonic blood flow was 18 +/- 2 ml per min and 100 g of colonic tissue (mean +/- SE; n = 21). In the muscularis layer blood flow amounted to 11 +/- 1 ml per min and 100 g of muscularis tissue (n = 12), and flow in the mucosa-submucosa was calculated to be 28 +/- 5 ml per min and 100 g of mucosal-submucosal tissue. A major fraction (66 +/- 6%) of total blood flow was distributed to the mucosa-submucosa. As total colonic blood flow was enhanced the increase in flow was diverted only to the mucosa-submucosa. The feline and human large bowel exhibited great qualitative and quantitative circulatory similarities.

Animals↗
PubMed1976

Blood flow in the small intestine of cat and man as analyzed by an inert gas washout technique.

Using a recently developed 85Kr-elimination technique, blood flow and flow distribution of the human small intestine have been investigated in patients during abdominal surgery. Total intestinal blood flow was estimated to be 38 +/- 4 ml per min and 100 g of intestinal tissue (mean +/- SE: n = 19), jejunal blood flow being slightly higher than ileal. In 14 of these patients muscularis blood flow was determined to be 21 +/- 2 ml per min and 100 g of muscularis tissue and mucosal-submucosal blood flow was calculated to be 51 +/- 6 ml per min and 100 g of mucosal-submucosal tissue. Seventy-five +/- 3% of total blood flow was distributed to the mucosa-submucosa and the remaining 25 +/- 3% to the muscularis. It was demonstrated that an increasing fraction of flow was diverted to the mucosa-submucosa with enhanced total intestinal blood flow. The human gut exhibited great qualitative and quantitative circulatory similarities with the feline small intestine.

Animals↗
PubMed1975

A method for the continuous study of net water transport in the feline small bowel.

A new perfusion technique has been developed for the study of net water transport across the intestinal epithelium in vivo. The lumen of an isolated intestinal segment is steadily perfused with a solution of known composition in a closed perfusion system with a reservoir large enough to prevent recirculation. The intestinal segment may be enclosed in a plethysmorgraph. Changes in the perfused volume is recorded by a volume transducer coupled to the recirculating system via a T-tube. If no motility occurs, the changes of the perfusion volume reflects net water transport across the intestinal epithelium. A quantitative comparison of this technique with the convention polyethylene glycol method revealed no significant difference. The plethysmorgraphic method also makes it possible to quantify the net water absorption via lymph and blood.

Animals↗
PubMed1975

Mucosal lesions in the human small intestine in shock.

Characteristic mucosal lesions in resected small intestinal segments from seven patients are reported. Preoperatively, four patients were in shock and general hypotension while the three remaining cases showed signs of local intestinal hypotension. The microscopic appearance of the mucosal lesions was in all patients identical with that previously observed in the feline and canine small intestine after haemorrhage or local intestinal hypotension. It is proposed that an extravascular short-circuiting of oxygen in the mucosal countercurrent exchanger and an intravascular aggregation of blood cells might produce tissue hypoxia which makes the mucosa vulnerable to enzymatic degradation.

Adult↗