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Biomedical subjects

J Svanvik

Publications and source records attributed to J Svanvik.

At least 109 records · Page 6Linked to original sources
PubMed1985

Adrenergic vasoconstriction in peripheral nerves of the rabbit.

The blood flow in the sciatic nerve of the rabbit was estimated from the wash out of intraneurally injected 133Xe. To avoid diffusion of the tracer into the surrounding muscular tissue, the nerve was covered by a gas-tight plastic film. Using this technique, the basal blood flow in the sciatic nerve was estimated to 35 ml X min-1 X 100 g-1. It was found that intraarterial norepinephrine and electrical stimulation of the lumbar sympathetic chain strongly reduced the wash out of 133Xe, which only can be explained by a pronounced reduction of the blood flow in the nerve itself. The blood flow again increased within 4 min of stopping the infusion of norepinephrine or the sympathetic stimulation. The prolonged effect and higher neurotoxicity of local anesthetics containing adrenaline may be explained by an alpha receptor-mediated vasoconstriction of the microvessels of peripheral nerves.

Animals↗
PubMed1985

The effects of morphine and enkephaline on gallbladder function in experimental cholecystitis. Inhibition of inflammatory gallbladder secretion.

Administration of morphine or its derivatives is the traditional way to treat biliary pain. Despite the common use of morphine and its analogues in patients with cholecystitis and biliary pain, their effects on the function of the inflamed gallbladder are not known. In the present study it is demonstrated that morphine usually contracts the normal gallbladder but does not influence the fluid transport across the mucosa. In experimental cholecystitis morphine and enkephaline do not further contract the gallbladder but, by specific opioid receptors, reduce the inflammatory fluid secretion by the mucosa. In case of obstruction of the gallbladder, fluid secretion by the mucosa will distend its wall and induce biliary pain. It is suggested that the pain-relieving effect of morphine in cholecystitis and attacks of biliary pain is mediated not only by a central analgesic effect but also by an influence on the function of the inflamed gallbladder.

Animals↗
PubMed1985

Indomethacin reduces raised intraluminal gallbladder pressure in acute cholecystitis.

Indomethacin was recently shown to have a potent analgesic effect on biliary pain. The underlying mechanism is not fully clear, although reduction of increased gallbladder pressure by inhibition of prostaglandin synthesis had been suggested. For further clarification of this mechanism, the effect of intravenous indomethacin on the intraluminal gallbladder pressure was investigated in patients undergoing operation for acute cholecystitis. After laparotomy, gallbladder pressure was measured continuously during 25 min in 20 patients, 10 of whom received 100 mg indomethacin intravenously, while 10 were untreated controls. High intraluminal gallbladder pressure was found in all patients. Indomethacin reduced the average pressure by 11% in 20 min, whereas the corresponding pressure in the controls was constant. The results indicate that acute cholecystitis is associated with substantially raised intraluminal pressure, and that the analgesic action of indomethacin on biliary pain may be attributable to a local effect on gallbladder function, resulting in reduction of intraluminal pressure.

Acute Disease↗
PubMed1984

The diagnostic value of the hemoccult as a screening test in patients taking anticoagulants.

The value of a 3-day Hemoccult II test in the diagnosis of colorectal disease in patients receiving anticoagulant therapy was studied. The influence of rehydration and nonrehydration of the slide was investigated, as well as the reproducibility of positive tests. Eight hundred forty-nine patients on anticoagulant therapy performed three Hemoccult II tests each. One hundred twenty-eight (15%) had one or more positive slides, when these were rehydrated. Three patients with carcinoma and 13 patients with adenomas were found among these 128 patients. One hundred twenty-one of these patients performed six duplicate Hemoccult II tests with four samples from each of three consecutive stools. Three of the six slides were rehydrated and three were not rehydrated before development. Forty-one and 23 patients, respectively, showed positive test results. Two of three reinvestigated patients with large bowel carcinoma had positive slides in both of these series. Seven and 2, respectively, of 13 patients with adenomas had positive tests in the second series when the slides were developed with and without rehydration. Thus, the predictive value was low with nonrehydrated slides, and the precision was low when the slides were rehydrated. It is concluded that the sensitivity of a 3-day Hemoccult II test without rehydration is too low to permit its use as a screening method for colorectal neoplasms in patients receiving anticoagulant therapy.

Adenoma↗
PubMed1984

The influence of somatostatin on gallbladder response to intraduodenal acid and autonomic nerve stimulation in the cat.

The influence of somatostatin on the concentrating function and motility of the feline gallbladder has been studied with perfusion techniques in vivo. Somatostatin did not cause any change in the basal volume or concentrating function of the gallbladder. Duodenal acidification and also efferent electrical stimulation of the vagus nerves after atropinization reduced the net water absorption from the gallbladder, and these effects were blocked by intravenous somatostatin. The enhanced rate of net water absorption in response to electrical stimulation of the splanchnic nerves, however, was not influenced by somatostatin. Both the gastrointestinal peptides vasoactive intestinal peptide (VIP) and secretin reduce the net water absorption in the gallbladder. The blocking effect of the gallbladder's response to duodenal acid might be explained by an inhibition by somatostatin of secretin release from the duodenum. The inhibition of the gallbladder's reaction to vagal stimulation can be explained by a suppression of VIP release from noncholinergic, nonadrenergic nerve fibres in the gallbladder wall. Apart from the earlier described interference with gallbladder emptying, somatostatin seems to affect the regulation of the gallbladder's concentrating function. The results are discussed in view of the recent observation that patients with somatostatinoma characterized by high levels of circulating somatostatin usually have gallstone disease.

Animals↗
PubMed1984

The concentrating function of the feline gallbladder after truncal vagotomy.

Truncal vagotomy is associated with a raised incidence of cholesterol gallstone disease and increase in the size of the gallbladder and of the bile acid pool. Investigations of hepatobiliary function in man and mammals after truncal vagotomy have not established if the enlarged gallbladder is simply dilated, or if the absorptive capacity of the mucosa has changed. We studied the concentrating function of the gallbladder with a perfusion technique in anaesthetized cats three weeks and three months after intrathoracic truncal vagotomy and compared the results with a control group. The histology of the gallbladder was studied with light microscopy. Three weeks after vagotomy the gallbladder size, histologic picture and concentrating function did not differ from observations in the control cats. Three months after the vagotomy the gallbladder was slightly enlarged, sludge was found in the luminal contents, an inflammatory response was seen in the mucosa and the net rate of water absorption was increased two to three times compared with the controls. Possible mechanisms in the increased rate of net water absorption are tentatively discussed.

Animals↗
PubMed1984

Variations in concentrating function of the gallbladder in the conscious monkey.

Hepatic bile is concentrated in the gallbladder by absorption of water and electrolytes. The rate of water absorption can be influenced in vitro and in vivo by gastrointestinal hormones and neurogenic transmitters. Recent studies have demonstrated that besides its absorbing activity, the gallbladder has the ability to secrete fluid into its lumen. In the present experiments, we studied the rate of net water absorption in the gallbladders of pig-tailed monkeys sitting in restraining chairs. Bile from the common bile duct and the gallbladder was led out through cannulas to a stream splitter, samples were obtained, and bile was returned to the duodenum. By measuring outflow from the gallbladder and the concentration of bile acids in hepatic bile and bile that had passed through the gallbladder, net water absorption from the gallbladder bile could be calculated. The results demonstrate that during daytime fasting there was a net absorption corresponding to 30% of the fasting gallbladder volume per hour, and after feeding there was a net secretion of fluid into the gallbladder lumen. Compared with the awake fasting state, net water absorption from the gallbladder decreased at night while the animal was fasting and asleep. Physiologically, secretion of fluid after a meal could help to empty the gallbladder, and changes in net water absorption by the gallbladder could influence the kinetics of the enterohepatic circulation of bile acids.

Absorption↗
PubMed1983

Influence of electrical vagal stimulation and acetylcholine on the function of the feline gallbladder.

The effects of electrical stimulation of the vagus nerves on the function of the feline gallbladder and hepatic bile outflow were studied with a perfusion technique in vivo. After elimination of the muscarinic receptors with atropine, efferent stimulation of the cut vagus nerve in the neck relaxed the gallbladder, reduced the net water absorption rate across its wall, and increased the bile outflow from the liver. The results imply that the concentrating function of the gallbladder and the bile formation in the liver are under regulatory control by noncholinergic, nonadrenergic nerve fibres in the vagus nerves.

Acetylcholine↗
PubMed1983

The effect of lysophosphatidylcholine on gallbladder function in the cat.

The effects of lysoPC on gallbladder net fluid transport and motility were investigated by a perfusion technique in the anesthetized cat. It was found that addition of 1 mumol/ml lysoPC to the buffer perfusate resulted in an immediate contraction of the gallbladder and also a change in net fluid transport from a basal absorption of 0.71 ml/hr to a secretion of 0.34 ml/hr. An increased output of hexosamine and protein from the gallbladder accompanied the lysoPC treatment. Indomethacin--a prostaglandin synthetase inhibitor--at a dose of 2 mg/kg caused a relaxation of the gallbladder and abolished the secretion but did not return the gallbladder to its original rate of basal absorption. LysoPC, when added to bile, had a similar effect on net fluid transport but did not induce a contraction of the gallbladder. The results indicate that the effect of lysoPC on gallbladder function could be of importance in acute cholecystitis and that endogenous prostaglandin synthesis may play a part in this lysoPC-induced inflammatory response.

Animals↗
PubMed1982

Adrenergic influence on concentrating function in the feline gall bladder.

The influence of adrenergic drugs and electrical stimulation of the splanchnic nerves on concentrating function and motility in the feline gall bladder and on heptic bile secretion have been studied in vivo. It was found that electrical stimulation of the splanchnic nerves and adrenergic alpha-receptor stimulation increase the rate of net water absorption from the gall bladder lumen. Adrenergic beta-receptor stimulation relaxed the gall bladder but did not influence the concentrating function. A direct effect on the mucosal cells and/or a ganglionic inhibition of intramural VIP-releasing neurons is suggested as a possible mechanism for the alpha-adrenergic increase of the net water absorption rate. The results are discussed in relation to the adrenergic influence on water absorption in the small intestine. As a functional consequence of an increase in the concentrating activity of the gall bladder in situations of high adrenergic activity a more rapid accumulation of organic contents in its lumen is suggested.

Absorption↗