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Biomedical subjects

L Rentzhog

Publications and source records attributed to L Rentzhog.

At least 19 recordsLinked to original sources
PubMed1984

Delayed dopamine treatment of segmental small intestinal ischaemia in the rat.

Two groups of rats were subjected to segmental ischaemia of the small intestine for 2 h. According to our previous findings such ischaemia causes impairment of the central circulation as well as of the splanchnic blood flow. Dopamine treatment was initiated 30 or 90 min after the establishment of ischaemia. In the 30-min group cardiac output increased and the blood flow was normalized in those parts of the small intestine where the arteries were not ligated (the non-occluded parts). This result corresponds well to our previous observations when dopamine treatment was started immediately after the establishment of ischaemia. In the 90-min group cardiac output was not affected. Again the intestinal blood flow was normalized in the non-occluded parts. In both groups the pancreatic circulation was impaired.

Animals↗
PubMed1984

Haemodynamic effects of phenoxybenzamine and dopamine in segmental ischaemia of the rat small intestine.

Two groups of rats were subjected to a segmental intestinal ischaemia of a degree which, according to earlier investigations with this experimental model, causes secondary impairment of the splanchnic blood flow. Both groups were given plasma and an alpha-adrenergic blocking agent (phenoxybenzamine). They were also given dopamine but in different doses, 12 and 50 micrograms X min-1 X kg-1 b.w., respectively. It was found previously that a normal blood flow in the non-occluded parts of the small intestine could be maintained by phenoxybenzamine or the lower dose of dopamine alone in combination with plasma, but the higher dopamine dose caused vasoconstriction, probably because of an alpha-stimulating effect. The combined treatment with penoxybenzamine and dopamine in the present experiments normalized the intestinal blood flow in the non-occluded parts in both groups, i.e. also in the group treated with the higher dose of dopamine. Moreover, the pancreatic circulation was normalized in both groups. Hence alpha-adrenergic blockade combined with dopamine and plasma administration seems to have a positive effect on the splanchnic circulation during segmental intestinal ischaemia in the rat.

Animals↗
PubMed1983

A comparative study on the analgesic effects of indomethacin and hydromorphinechloride-atropine in acute, ureteral-stone pain.

In a prospective study, including fifty consecutive patients with acute ureteral-stone pain, the patients were randomly distributed into two groups for treatment. There were given either an intravenous injection of indomethacin (Confortid) 50 mg, or a subcutaneous injection of 2 mg hydromorphine chloride-atropine (Dilaudid-atropin 1 ml). Patients in the latter group also received a suppository of prochlorperazine (Stemetil) 25 mg. The analgesic effect of the two drugs did not differ significantly. Indomethacin was quicker acting, probably due to the intravenous route of administration. The side effects were alike but those caused by indomethacin had a tendency to be milder and of shorter duration.

Adult↗
PubMed1978

Regional and central hemodyanamics during segmental ischemia of the small intestine in the rat.

The influence of segmental small intestinal ischemia on the central circulation and on the regional blood flow to consecutive segments of the small intestine in the rat was investigated with the microscphere method. Ischemia was established by ligating 11 arterial mesenteric end arcades, corresponding to one quarter of the total length of the small intestine. The blood supply to different organs and central circulatory variables were determined before, and 10 min, 30 min, 2 h and 14 days after the establishment of the ischemia. After 10 min of ischemia, there was an increase of the blood flow to the segments distal to the ischemic region but after 30 min, this blood flow was the same as the control flow. The central circulatory variables weere not affected. After 2 h of ischemia, the blood supply to both the ischemic and the non-ischemic part of the small intestine had deteriorated considerably. Thus, the vascular resistance in the ischemic segments and the segments surrounding it was increased. Cardiac output was reduced by about 50%. In the experimental group investigated 14 days after establishment of the ischemia, the mortality rate was about 50%. In the survivors, the intestinal blood supply had returned to normal.

Animals↗
PubMed1978

Propulsion and mixing of small bowel contents after laparotomy in rat.

Radioactive test substances were infused slowly into the duodenum of conscious rats via a permanent catheter starting 2, 12 and 24 h after a standardized laparotomy. Two differently labelled but otherwise identical test substances were used. The first test substance (125I-PVP) was infused for 4 h, the second (131I-PVP) for the remaining 1 h of the 5-hour infusion period. Immediately after the infusion the animals were killed, and the radioactivity emanating from each isotope was recorded from the excised bowel specimen. The bowel length passed by the border zone and the degree of overlap between the labels in this zone were taken as measures of propulsion and mixing, respectively. Propulsion and mixing were uninfluenced by laparotomy as measured 2--17, 12--17 and 24--29 h after laparotomy. The present findings indicate that laparotomy is not followed by a disturbance in the capability of the small bowel to transport and mix chyme, at least when no high demands with respect to chyme volume are required.

Animals↗
PubMed1978

Microsphere measurement of regional intestinal blood supply and cardiac output in the rat.

The regional blood supply to consecutive segments of the small intestine in the anaesthetized rat was investigated with a radioactive microsphere technique. A blood flow gradient with the lowest flow in the distal segments (0.85--0.89 ml/min.g) and the highest in the proximal segments (1.13--1.15 ml/min.g) was observed. Very few microspheres were found in the portal vein blood, indicating negligible arteriovenous shunting in the splanchnic area. The mean cardiac outputs in two consecutive measurements were 27.9 and 28.7 ml/min . 100 g, respectively. The cardiac output and regional blood flow values were in accordance with those obtained with other techniques.

Animals↗
PubMed1978

Hemodynamic effects of phenoxybenzamine and volume replacement in segmental ischemia of the rat small intestine.

Segmental ischemia of the small intestine in the rat was established by ligating the mesenteric arterial end arcades of 1/4 of the length of the small intestine. Regional and central blood flow was measured with the microsphere technique before and 2 h after induction of the ischemia. In one series of rats an i.v. infusion of 16 ml plasma per kg body weight (b.w.) was given during the experimental period, which maintained the central circulation. However, the impairment of blood supply to the whole small intestine caused by the segmental ischemia was not normalized. Two other series of rats were treated with either phenoxybenzamine alone, 3 mg.kg-1 b.w., or the same dosage of phenoxybenzamine plus plasma infusion (16 ml.kg-1 b.w.). The central circulation was deteriorated and the blood flow to the small intestine reduced in the rats receiving phenoxybenzamine alone. Both the central circulation and the blood supply to the non-ischemic parts of the intestine were maintained in rats treated with both phenoxybenzamine and plasma. Combined treatment with phenoxybenzamine and volume replacement thus seems to be valuable for limiting the secondary hemodynamic changes caused by segmental intestinal ischemia.

Acid-Base Equilibrium↗
PubMed1978

Hemodynamic effects of methylprednisolone in rats subjected to segmental intestinal ischemia.

Massive doses of methylprednisolone were given to rats subjected to segmental intestinal ischemis. The central and regional blood flows were studied with the microsphere technique. Ischemia was induced by ligating the arteries to 1/4 of the length of the small intestine. In rats subjected to 2 h of segmental intestinal ischemia methylprednisolone seemed to prevent the decrease in blood flow, previously noted in untreated rats, in the regions where the arteries were not occluded. When adequate volume replacement was given in combination with methylprednisolone, the blood flow in the ischemic region showed a slight improvement. The edema in the ischemic segments tended to be less marked in rats treated with methylprednisolone.

Animals↗
PubMed1976

The effect of digitalis on regional ischaemia of the rat small intestine.

Research in recent years has shown that under certain conditions digitalis has a strong vasoconstrictive effect in the splanchnic region. This may imply that in cases of mesenteric ischaemia, digitalization may inhibit a collateral circulation necessary for restoration of the intestinal function. In this investigation the effect of digitoxin on the exchange circulation of the small bowel mucosa was studied in rats with induced regional ischaemia of the intestine. On analysis 30 min after establishment of the ischaemia a statistically significant negative effect of digitoxin was observed.

Animals↗
PubMed1976

Effect of chemical sympathectomy (6-hydroxydopamine) on gastrointestinal propulsion after laparotomy. An experimental study in the rat.

The effect of chemical sympathectomy on gastric evacuation and small bowel propulsion 15 hours after a standardized laparotomy was evaluated. The animals were pre-treated with 50 mg/kg i. v. of 6-hydroxydopamine 15 or 48 hours or 150 mg/kg 48 hours before the evaluation of gastrontestinal propulsion. The treatment did not prevent the postoperative retardation. On the contrary 6-hydroxydopamine in itself seemed to retard gastrointestinal propulsion. In simultaneously adrenal demedullated rats no further retardation was produced by the laparotomy.

Abdomen↗
PubMed1976

Effect of adrenergic blockade on gastrointestinal propulsion after laparotomy. An experimental study in the rat.

The effects of alpha-adrenergic and beta-adrenergic blockade on gastric evacuation and small bowel propulsion 15 hours after standardized laparotomy were evaluated. No retardation of gastric evacuation after the laparotomy appeared when alpha-receptor blocking treatment with phenoxybenzamine was instituted. Beta-receptor blocking treatment with propranolol did not prevent the retardation of gastric evacuation after the laparotomy. The time of analysis, 15 hours after the laparotomy, seemed to coincide with the period of resumption of normal small bowel propulsion.

Abdomen↗
PubMed1976

Effects of sympatho-adrenal activity and pharmacological treatment on gastrointestinal propulsion in the early postoperative period. An experimental study in the laparotomized rat.

Gastric evacuation and small bowel propulsion were greatly retarded two hours after laparotomy in the rat. Adrenal demedullation, chemical sympathectomy with 6-hydroxydopamine or treatment with a cholinesterase inhibitor (Neostigmin), an alpha-receptor blocker (Dibenyline) or metoclopramide (Primperan) did not improve the gastric evacuation. Chemical sympathectomy or treatment with metoclopramide, however, significantly improved small bowel propulsion. A significant reflux of duodenal contents to the stomach was found in several animals treated with the cholinesterase inhibitor or subjected to adrenal demedullation.

Abdomen↗