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Biomedical subjects

A Thune

Publications and source records attributed to A Thune.

31 records · Page 2Linked to original sources
PubMed1992

Sphincter of Oddi regulates flow by acting as a variable resistor to flow.

Two models of transsphincteric flow and a model evaluating pumping activity were established in the anesthetized Australian brush-tailed possum to determine whether the sphincter of Oddi (SO) acts as a resistor or as a pump. A simple model of transsphincteric flow (inflow only) demonstrated that at physiological common bile duct (CBD) pressure, 9.5 +/- 0.3 cmH2O (n = 7), transsphincteric flow occurred between SO pressure waves (n = 10). A second more complex transsphincteric flow model was established that permitted simultaneous measurements of inflow, outflow, CBD pressure, SO basal pressure, SO contraction frequency, and amplitude. At physiological CBD pressure, inflow always equaled outflow (157.0 +/- 11.2 and 156.4 +/- 11.4 microliters/min, respectively; n = 7). The SO displayed regular contractions superimposed on a basal pressure of 1.1 +/- 0.4 mmHg. Contraction amplitude was 12.6 +/- 3.0 mmHg and the frequency was 3.6 +/- 0.4 contractions/min (n = 7). Pressure waves recorded in the CBD corresponded to the SO contractions and reflected SO activity. Transsphincteric flow occurred between SO contractions and was obstructed by these contractions. Stimulation of SO activity (basal pressure and contraction frequency) with intra-arterial injections of motilin (200 ng/kg) or erythromycin (200 micrograms/kg) abolished transsphincteric flow. Reduction in SO contraction frequency to 72.7 +/- 7.2% (P < 0.01, paired t test) after administration of Cisapride (2 mg/kg iv) increased transsphincteric flow to 147.6 +/- 12.3% (n = 7, P < 0.05, paired t test). In six possums, possible SO pumping action was evaluated. A manometer was connected to the CBD, and a second manometer was connected to the duodenum surrounding the papilla.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

[Externalizing the problem--a method in psychiatric treatment].

Michael White is an Australian family therapist. He has developed a therapeutical method which he calls "externalizing the problem". According to this method, the patient's problem is given a linguistic designation, for example "the tyrant of anguish", "the tempter of drugs", "the black voice", and is kept outside the dominant identity of the patient. The patient, in time also the family, is invited to a dialogue on the effect of this problem and how to develop strategies to beat "the problem tyrant". The authors have based their work on the thoughts and methods of Michael White. They have used these methods to address a wide range of psychiatric problems. The paper describes the theory behind the methods, and presents a number of clinical examples where they have been used.

Adolescent↗
PubMed1991

Reproducibility of endoscopic sphincter of Oddi manometry.

Results from endoscopic sphincter of Oddi manometry are being used to support the diagnosis of sphincter dysfunction in patients with unexplained pain after cholecystectomy. However, there are few data on the reproducibility of manometric records or motility diagnosis during a second test. In this study, the reproducibility of manometric records was assessed in 12 patients with pain after cholecystectomy by performing a second study after three months. Manometric tracings were evaluated without access to patients details and scored for sphincter basal pressure, frequency and amplitude of phasic contractions, propagation of phasic contractions, and responses to intravenous injection of cholecystokinin octapeptide (20 ng/kg). At the initial manometric study, four patients were diagnosed as normal, four as stenotic, and four as dyskinetic. Those diagnosed as normal and stenotic at the first study had an identical diagnosis at the second study. However, the diagnosis of dyskinesia was reproduced only in two of the four patients. In the other two patients a diagnosis of "stenosis" and "normal" was made at the second study. Cholecystokinin octapeptide (20 ng/kg intravenous bolus) produced inhibition of phasic contractions in all studies, both initially and at three months. We conclude that endoscopic sphincter of Oddi manometry is reproducible when the initial diagnosis is either normal or stenosis. However, the diagnosis of dyskinesia is poorly reproducible, perhaps due to the episodic nature of this manometric disorder or to progression of sphincter of Oddi dysfunction.

Adult↗
PubMed1991

Distension of the gall bladder inhibits sphincter of Oddi motility in humans.

Studies in animals have suggested a neural reflex between the gall bladder and the sphincter of Oddi. The aim of this study was to investigate whether sphincter of Oddi motility is altered by distension of the gall bladder in humans. Sphincter of Oddi motility was recorded intraoperatively in 10 patients undergoing elective cholecystectomy for gall stones. The manometry was performed by a triple lumen constantly perfused catheter which was introduced through the cystic duct and positioned across the sphincter of Oddi to record sphincter basal pressure, wave amplitude, and frequency of contractions. In five patients a separate catheter was introduced into the gall bladder after ligation of the cystic duct. This catheter was used to distend the gall bladder. Sphincter of Oddi pressures were measured before, during, and after the distension. In a separate control group of patients (n = 5) basal sphincter of Oddi activity was recorded without distension of the gall bladder. Distension of the gall bladder decreased sphincter of Oddi basal pressure from (mean (SD] 22.8 (8.5) mmHg to 18.6 (6.5) mmHg (p = 0.01, paired t test) and frequency of sphincter of Oddi contractions decreased from 2.6 (1.6) to 1.1 (1.3) contractions/min (p = 0.003, paired t test). The results were significantly different from those of the control group (p less than 0.05, unpaired t test) during the same time period (four minutes). Pulse rate and blood pressure were not affected by the gall bladder distension. The results suggest a local reflex between the gall bladder and the sphincter of Oddi that might be important in the regulation of the pressure within the bile ducts and flow across the sphincter. This reflex is likely to be neurally mediated and injuries to it may be important in the aetiology of postcholecystectomy sphincter of Oddi dysfunction.

Adult↗
PubMed1990

Differing effects of pethidine and morphine on human sphincter of Oddi motility.

The aim of this study was to evaluate the effects of morphine and pethidine on human sphincter of Oddi motility. The action of these opioids on the sphincter of Oddi was evaluated by means of intraoperative manometry in 36 patients undergoing elective cholecystectomy. Both opioids were given in intravenous cumulative equipotent doses up to a maximum of 10 micrograms/kg morphine or 100 micrograms/kg pethidine. At these doses, morphine increased the mean(s.d.) frequency of contractions from 2.4(1.0) to 7.9(1.6) (P less than 0.001); this effect was reduced by naloxone (0.04 mg bolus, P less than 0.05). Pethidine inhibited the frequency of contractions from 1.5(0.8) to 0.8(0.5) (P less than 0.05); this response was blocked by atropine (0.6 mg bolus, P less than 0.01). Pretreatment with atropine or naloxone reduced the frequency of contractions significantly (P less than 0.05). The results illustrate different responses to pethidine and morphine of the sphincter of Oddi, and provide a pharmacological explanation for the suitability of pethidine over morphine as the analgesic of choice in patients experiencing biliary pain.

Adult↗
PubMed1990

Functional and morphological relationships between the feline main pancreatic and bile duct sphincters.

To analyze the relationships between the bile duct and main pancreatic duct sphincters, the resistance to flow through these sphincters was studied simultaneously with perfusion techniques in anesthetized cats. Basal flow resistance was higher in the pancreatic sphincter than in the bile duct sphincter. The pressure in one duct system was not affected by the flow in the other. The muscular activities in the sphincters were usually well coordinated. Distention of the upper biliary tract or the pancreatic duct system reduced the flow resistance in both sphincters. Cholecystokinin-8 (0.01 micrograms), duodenal distention, and sublingual glyceryl trinitrate (0.4 mg) also relaxed both sphincters, whereas secretin in a dose that induced pancreatic secretion had no consistent effect. Morphine increased flow resistance in both systems. These functional studies indicate that the 2 sphincters share smooth muscle fibers at the level where the flow resistances arise, and there are thus no grounds for separate control of the sphincters. There was no evidence of a functionally common sphincter ampulla. The conclusions drawn from the manometric results were supported by morphological findings in this study.

Animals↗
PubMed1989

Naloxone-reversible inhibition of gall-bladder mucosal fluid secretion in experimental cholecystitis in the cat by acetorphan, an enkephalinase inhibitor.

1. Enkephalin immunoreactive nerve fibres have been demonstrated in the gall bladder of various mammals including man. In various tissues, enkephalins are partly degraded by a membrane metallo-endopeptidase, enkephalinase (EC 3.4.24.11). 2. Using 3H-labelled [D-Ala2,Leu5]enkephalin as a substrate, enkephalinase activity, immunoprecipitated by a monoclonal antibody directed against the rabbit kidney enzyme, was demonstrated in the feline gall bladder. Using the same antibody in 125I-labelled form, the peptidase was immunolocalized by autoradiography, mainly in the epithelium. 3. In experimental cholecystitis, elicited by implantation of human gall-stones into the cat gall bladder, the continuous fluid secretion into the lumen was inhibited by exogenous enkephalins. 4. Acetorphan, an enkephalinase inhibitor, was found to block fluid secretion by the inflamed gall bladder via a naloxone-sensitive mechanism, but not to affect fluid transport in the normal gall bladder. The drug also transiently contracted the gall bladder and increased bile outflow from the liver. 5. It is suggested that acetorphan, by reducing the degradation of endogenous enkephalins in the inflamed gall bladder, decreases fluid secretion by the epithelium and that enkephalinase inhibitors may find clinical applications in acute cholecystitis.

Animals↗
PubMed1989

Flow resistance in the feline choledocho-duodenal sphincter as studied by constant-pressure and constant-perfusion techniques.

During interdigestive periods, there is a resistance to flow in the biliary tract exerted by the sphincter of Oddi, resulting in a pressure gradient between the common bile duct and the duodenum. In this experimental study, this flow resistance was studied with both a constant-flow and a constant-perfusion technique in fasted, anaesthetized cats. The flow resistance exerted by the sphincter is higher when it is perfused by a constant flow compared to when the common bile duct pressure is kept constant and the flow varies in response to its muscular activity. It was demonstrated with each method that the flow resistance in the choledocho-duodenal junction is reduced in response to distension of the biliary tree and gallbladder and also by distension of the duodenum. Cholecystokinin was shown to reduce the flow resistance in the choledocho-duodenal junction as estimated with either method.

Ampulla of Vater↗
PubMed1988

Intraluminal prostaglandin E2 affects gallbladder function by activation of intramural nerves in the anaesthetized cat.

Gallbladder mucosal net fluid transport and motility were measured in vivo by a continuous perfusion technique in the anaesthetized cat. Prostaglandin E2, administered to the perfused gallbladder lumen, caused a contraction decreasing gallbladder volume capacity, and induced a secretory response by the mucosa. These effects by prostaglandin E2 were abolished by the nerve-blocking agent tetrodotoxin (administered close intraarterially) and somatostatin (administered intravenously), but not by intravenous hexamethonium. Atropine (administered intravenously) reduced the order of magnitude of the gallbladder contraction in response to prostaglandin E2 but did not affect the secretory response by the mucosa. Neither of these drugs significantly affected gallbladder volume capacity or mucosal fluid transport during basal conditions. Tetrodotoxin did not abolish the gallbladder responses to intravenous cholecystokinin or vasoactive intestinal peptide, peptides known to act directly upon smooth muscle and epithelial cell receptors, respectively. It is suggested that prostaglandin E2 affects gallbladder function in vivo mainly by activation of postganglionic non-cholinergic intramural nerve cells.

Animals↗
PubMed1988

Cholecystectomy in the cat damages pericholedochal nerves and impairs reflex regulation of the sphincter of Oddi. A mechanism for postcholecystectomy biliary dyskinesia.

A recent study demonstrated the activity of the feline sphincter of Oddi to be regulated by the distending pressure in the biliary tract via inhibitory nerves running along the common bile duct. In the present study this mechanism was investigated in cats previously subjected to cholecystectomy. An increment in the hydrostatic pressure in the biliary tree from 0 to 20 cmH2O did not affect the function of the sphincter of Oddi in cholecystectomized cats, but relaxed the sphincter in controls and in cats with sham operation. Morphologic study of the nerve arrangement in the feline extrahepatic biliary tract revealed that cholecystectomy is likely to damage pericholedochal nerves. These experimental observations may have relevance for the development of biliary dyskinesia following cholecystectomy in some patients, and suggest that when performing biliary-tract surgery it is important to preserve nerve fibers running along the common bile duct.

Ampulla of Vater↗
PubMed1986

Reflex regulation of flow resistance in the feline sphincter of Oddi by hydrostatic pressure in the biliary tract.

Despite wide variations in bile secretion and biliary tract capacitance, the pressure in the bile ducts is fairly constant. Recent studies have demonstrated that both inhibitory and excitatory nerves regulate the activity of the sphincter of Oddi. In the present study, it was consistently found that the resistance by the choledochoduodenal junction to a constant flow, within the physiologic range of hepatic bile output, is reduced when the hydrostatic pressure in the gallbladder and bile ducts is increased from 0 to 10, 0 to 15, and 0 to 20 cmH2O. This response was eliminated by tetrodotoxin or infiltration of the junction between the common bile duct and the cystic duct by mepivacaine, a local anesthetic. The results suggest a homeostatic mechanism during the interprandial periods, when the activity of the sphincter of Oddi is regulated by the distending pressure in the biliary tract. This reflex regulation is mediated by modulation of the activity of inhibitory nerves running along the common bile duct.

Ampulla of Vater↗
PubMedDate not supplied

Management of acute cholecystitis in the laparoscopic era: results of a prospective, randomized clinical trial.

The aim of this prospective, randomized study was to determine whether laparoscopic cholecystectomy should be performed as an early or a delayed operation in patients with acute cholecystitis. After diagnostic workup, patients were randomized to one of two groups: (1) early laparoscopic cholecystectomy (i.e., within 7 days after onset of symptoms) or (2) initial conservative treatment followed by delayed laparoscopic cholecystectomy 6 to 8 weeks later. Seventy-four patients were placed in the early-operation group, and 71 patients were assigned to the delayed-operation strategy. There was no significant difference in conversion rates (early 31% vs. delayed 29%), operating times (early 98 [range 30 to 355] minutes vs. delayed 100 [45 to 280] minutes), or complications. Failure with the conservative treatment strategy was noted in 26% of these patients. The total hospital stay was significantly shorter in the early group (5 [range 3 to 63] days) vs. the delayed group (8 [range 4 to 50] days; P<0.05). Despite a high conversion rate, early laparoscopic cholecystectomy offered significant advantages in the management of acute cholecystitis compared to a conservative strategy. The greatest advantage was a reduced total hospital stay.

Acute Disease↗