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Biomedical subjects

J Toouli

Publications and source records attributed to J Toouli.

At least 91 records · Page 5Linked to original sources

Minimal access surgery of the gastrointestinal tract.

In the last 5 years, surgery of the gastrointestinal tract has been revolutionized by the application of minimal access techniques. Following initial enthusiasm, which suggested that most abdominal surgery would ultimately be done via this approach, there is now need for appraisal and evaluation of the role of a number of these minimal access techniques when compared with open surgery. Undoubtedly, the most convincing and total application of minimal access techniques has been in the treatment of gallstone disease. Laparoscopic cholecystectomy is now standard therapy for cholelithiasis and endoscopic sphincterotomy with stone extraction is standard therapy for choledocholithiasis. Where the two conditions co-exist, operative cholangiography allows for the recognition of stones in the bile duct at the time of laparoscopic cholecystectomy and provides the potential avenue for treatment. Most major centres also would recommend routine operative cholangiography during laparoscopic cholecystectomy for the detection of unsuspected stones and as an extra safety procedure in the early identification of potential bile duct injuries. The efficacy of laparoscopic appendicectomy and laparoscopic or thoracoscopic treatment of achalasia of the oesophagus also is supported by data from well conducted prospective studies. Doubt remains regarding the advantage of laparoscopic surgery over other approaches in the treatment of gastro-oesophageal reflux, inguinal hernias and jaundice due to non-resectable cancer. For all three of these conditions, prospective trials are underway and the results of these trials should be assessed prior to widespread adoption of the laparoscopic techniques.(ABSTRACT TRUNCATED AT 250 WORDS)

Cholecystectomy, Laparoscopic↗

Intramural neural pathways between the duodenum and sphincter of Oddi in the Australian brush-tailed possum in vivo.

1. Balloon distension of the duodenum 2 cm oral or anal to the sphincter of Oddi-duodenal junction elevated the amplitude of spontaneous sphincter of Oddi phasic contractions by 37.7 +/- 8.5 or 120.1 +/- 79.8%, respectively (mean +/- S.E.M., both n = 6, P < 0.05, Wilcoxon test). To further investigate this response, this study aimed to determine if: (i) electrical field stimulation (EFS) of the duodenum influences sphincter of Oddi activity; (ii) intramural nerves mediate the response; and (iii) nicotinic and/or muscarinic receptors are involved. 2. Electrical field stimulation (70 V, 0.5 ms; 5-60 Hz, 10-20 s) of the duodenal anterior serosal surface 2-4 cm oral or anal to the sphincter of Oddi-duodenal junction, produced excitatory responses in the sphincter of Oddi in anaesthetized Australian brush-tailed possums (n = 45). 3. These responses were frequency dependent, maximal at 30 Hz (n = 4) and abolished by tetrodotoxin (9 micrograms kg-1 I.A.; n = 6), or by crushing the duodenum (n = 3). Hexamethonium bromide (30 mg kg-1 I.V.) did not significantly alter the response to duodenal EFS either oral (n = 6) or anal (n = 8) to the sphincter of Oddi-duodenal junction. Atropine sulphate (30 micrograms kg-1 I.V.) reduced the response to duodenal EFS oral and anal to the sphincter of Oddi-duodenal junction to 11.2 +/- 5.8 (n = 6) and 45.0 +/- 26.8% (n = 8), respectively (both P < 0.05). 4. Bilateral cervical vagotomy and guanethidine infusion (10 mg kg-1 over 15 min I.V.) did not significantly alter the responses to duodenal EFS (n = 7). 5. Excitatory intramural neural pathways between the sphincter of Oddi and the segment of duodenum 4 cm oral and anal to the sphincter of Oddi-duodenal junction have been demonstrated. These postganglionic pathways may involve muscarinic receptors.

Animals↗

The value of serum carcinoembryonic antigen in predicting recurrent disease following curative resection of colorectal cancer.

UNLABELLED: Carcinoembryonic antigen (CEA) estimations are used to facilitate early diagnosis of recurrent disease after treatment for colorectal cancer. PURPOSE: This study was designed to determine the natural history of patients with normal and abnormal levels of CEA. METHODS: Patients undergoing potential curative resection of colorectal tumors (Dukes Stage A-C) entered a prospective, randomized trial comparing two follow-up regimens (to be reported separately) had CEA levels measured every 3 months for two years; then every 6 months for the next three years. In the study protocol, a rise in CEA was not an indication for investigation to determine recurrence unless there was also other evidence of recurrent disease. RESULTS: Three hundred eleven patients were followed for a median of 4.5 (range, 2-5) years. Recurrent disease developed in 98 (32 percent) patients, 57 of whom had an elevated CEA (sensitivity 58 percent), with a median lead time of six (range, 1-30) months from first abnormal CEA to diagnosis of recurrent disease by other means. The specificity, positive predictive value, and negative predictive value of CEA as an indicator of subsequent recurrent disease was 93 percent, 79 percent, and 83 percent, respectively. The sensitivity of CEA for predicting hepatic metastases was 80 percent, with a median lead time of eight (range, 1-30) months, compared with only 46 percent for sites of recurrent disease other than the liver. CONCLUSIONS: CEA was the first indicator of recurrent disease in 58 percent of all patients and in 80 percent of patients with liver metastases. The diagnosis of recurrent disease may be made several months earlier by investigating the first abnormal CEA level, although any benefit in terms of survival remains to be proven.

Aftercare↗

Endoscopic retrograde cholangiopancreatography following laparoscopic cholecystectomy.

Laparoscopic cholecystectomy is the preferred method of treatment for symptomatic choledocholithiasis. Since its introduction there has been an increase in postoperative diagnostic and therapeutic endoscopic retrograde cholangiopancreatography (ERCP). The aim of this study was to assess the indications and results of ERCP following laparoscopic cholecystectomy. Sixty-one patients had an ERCP following laparoscopic cholecystectomy. Two broad groups were identified: Group 1 (35 patients) had filling defects (consistent with stones) noted on operative cholangiography, which were not successfully flushed or extracted at the time of laparoscopic cholecystectomy; Group 2 consisted of patients who developed problems following laparoscopic cholecystectomy. Nine patients had post-laparoscopic cholecystectomy pain with abnormal liver function tests (LFT), four of whom had common bile duct (CBD) injuries and three had CBD stones. Eleven patients had post-laparoscopic cholecystectomy pain with a normal diameter common bile duct on ultrasound and normal LFT; only one had a CBD stone. Five patients with a persisting bile leak following laparoscopic cholecystectomy had an ERCP and endoscopic sphincterotomy. In three the leak ceased, while two required subsequent open surgery to drain bile collections and ligate the cystic duct. One patient presented with an episode of transient jaundice but had a normal ERCP. There were six post-ERCP complications; three patients had mild pancreatitis, two had a minor haemorrhage and one an asymptomatic duodenal perforation. Endoscopic retrograde cholangiopancreatography post-laparoscopic cholecystectomy was most valuable for the management of retained stones and the diagnosis and management of post-laparoscopic cholecystectomy pain in association with abnormal LFT. The diagnostic yield was low (9%) when the LFT were normal.

Adolescent↗

Duodenal web and pancreas divisum causing pancreatitis in an adult.

Duodenal malformations are the third commonest cause of intestinal obstruction in infants. A spectrum of intrinsic obstructive lesions within the duodenum ranges from atresia to congenital bands. Rarely, duodenal malformations may first present in adulthood. Less than 70 cases of duodenal web presenting in an adult have been reported in the literature. In 10 patients the presentation was associated with pancreatitis. We report a case of congenital duodenal web associated with pancreas divisum which first presented in an adult with the clinical characteristics of recurrent acute pancreatitis.

Acute Disease↗

Projections of nerve cells from the duodenum to the sphincter of Oddi and gallbladder of the Australian possum.

BACKGROUND: This study investigated the existence of direct neural connections between the duodenum and the biliary tract in the Australian possum. METHODS: Retrogradely transported neuronal dyes, Fast Blue and Dil, were injected into the wall of the gallbladder and the sphincter of Oddi. The duodenum, biliary tract, and sympathetic and sensory ganglia were examined for the presence of labeled cell bodies. RESULTS: Two to 3 weeks after gallbladder injection, labeled nerve cell bodies were found in the myenteric plexus of the proximal duodenum but were rare in the duodenum distal to the sphincter of Oddi. No neurons were found in the submucous plexus. Labeled nerve cells were also found in the sphincter of Oddi. After injection of the sphincter, labeled neurons were in both the submucous and myenteric plexuses of the duodenum, on either side. Approximately one third of labeled myenteric neurons were immunoreactive for enkephalin. Labeled cell bodies were also in the coeliaco-mesenteric, nodose, and dorsal root ganglia after both gallbladder and sphincter injection. After a myotomy on the proximal duodenum, no neurons were labeled on the pyloric side of the lesion by subsequent sphincter injection of dye. CONCLUSIONS: Direct neural pathways connect the duodenum with the gallbladder and the sphincter of Oddi, and the sphincter with the gallbladder; this implies that enteric nerve circuits participate in coordinating duodenal and biliary functions.

Animals↗

Nitric oxide mediates nonadrenergic, noncholinergic neural relaxation in the Australian possum.

BACKGROUND: Nitric oxide has been shown to play an important role in neurally mediated relaxations of gastrointestinal smooth muscle. The aim of this study was to determine whether NO may be the inhibitory transmitter to circular smooth muscle from the sphincter of Oddi of the Australian brush-tailed possum (Trichosurus vulpecula). METHODS: The effects of drugs on relaxations evoked by electrical-field stimulation of circular muscle strips precontracted with either erythromycin or carbachol were studied. Preparations were also processed histochemically to determine the presence of nicotinamide adenine dinucleotide phosphate (NADPH)-diaphorase reactivity in the tissue. RESULTS: NG-nitro-L-arginine methyl ester reduced the amplitude of relaxations; this effect could be partially reversed by millimolar concentrations of L-arginine but not by D-arginine. Oxyhemoglobin also reduced the amplitude of the relaxations, and sodium nitroprusside mimicked the relaxations in precontracted strips. Histochemical processing revealed the presence of nerve cell bodies and nerve fibers associated with the circular muscle layer, which are reactive for NADPH-diaphorase and are thus likely to contain NO synthase. CONCLUSIONS: These results are all consistent with NO released from nerve cells mediating a significant part of the nonadrenergic, noncholinergic relaxation of the circular muscle layer of the sphincter of Oddi.

Animals↗

Laparoscopic cholecystectomy for acute inflammation of the gallbladder.

OBJECTIVE: The aim of this study was to prospectively assess the results of laparoscopic cholecystectomy in patients with acute inflammation of the gallbladder. SUMMARY BACKGROUND DATA: Laparoscopic cholecystectomy has become the standard treatment for symptomatic gallbladder disease. Its role in the surgical treatment of acute cholecystitis has not been defined, although a number of recent reports suggest that there should be few contraindications to an initial laparoscopic approach. METHODS: All patients presenting with symptomatic cholelithiasis from October 1990 until June 1992 were evaluated at laparoscopy with intention of proceeding to a laparoscopic cholecystectomy. The gross appearance of the gallbladder was categorized as acute inflammation, chronic inflammation, or no inflammation. Ninety-eight (23.4%) of 418 patients had acute inflammation of the gallbladder: 55 were edematous, 10 were gangrenous, 15 had a mucocele, and 18 had an empyema. RESULTS: The authors assessed outcome in these patients. The frequency of conversion to an open operation was 33.7% for acute inflammation, 21.7% for chronic inflammation (p < 0.05), and 4% for no inflammation (p < 0.001). The conversion rate was highest for empyema (83.3%) and gangrenous cholecystitis (50%), while the conversion rate for edematous cholecystitis was 21.8% and for acute inflammation with a mucocele it was 7%. The median operation time for successful laparoscopic cholecystectomy for acute inflammation was 105 minutes, which was longer than that with no inflammation (90 minutes). However, the incidence of complications was not different from that for chronic or no inflammation. The median postoperative stay for patients with acute gallbladder inflammation was 2 days for successful laparoscopic cholecystectomy and 7 days for patients converted to an open operation. CONCLUSIONS: Laparoscopic cholecystectomy for acute inflammation of the gallbladder is safe and is associated with a significantly shorter postoperative stay compared to open surgery. A greater number of patients required conversion to open operation compared to those with no obvious inflammation. Conversion to open operation was most frequent for empyema and gangrenous cholecystitis, suggesting that once this diagnosis is made, excessive time should not be spent in laparoscopic trial dissection before converting to an open operation.

Acute Disease↗

Laparoscopic appendicectomy: a prospective analysis.

The potential advantages of laparoscopic surgery for a number of abdominal operations including appendicectomy have been heralded. In this study the aims were to assess prospectively the role of routine diagnostic laparoscopy in the diagnosis of acute appendicitis and determine the efficacy of laparoscopic appendicectomy. Patients with suspected acute appendicitis had diagnostic laparoscopy. When the diagnosis was confirmed laparoscopic appendicectomy was performed. Where an alternative diagnosis was made the appropriate treatment was instituted. If no diagnosis could be made the macroscopically normal appendix was removed by laparoscopic appendicectomy. Eighty-one patients (50 female, 31 male) had an initial diagnostic laparoscopy; 53 had appendicitis and proceeded to laparoscopic appendicectomy. A diagnosis could not be established at diagnostic laparoscopy in six patients and they also proceeded to laparoscopic appendicectomy. An alternative diagnosis was made in the remaining 22 patients (19 female and 3 male), with five proceeding to laparotomy and one patient with mesenteric adenitis having laparoscopic appendicectomy. Seven patients having laparoscopic appendicectomy required conversion to an open operation due to a retrocaecal or perforated appendix. The median operating time for successful laparoscopic appendicectomy was 55 min (range 30-95). Morbidity occurred in five of 53 patients having a successful laparoscopic appendicectomy. The median postoperative hospital stay was 2 days. The median time before return to normal activities was 8 days. Diagnostic laparoscopy is a useful diagnostic technique in women with suspected acute appendicitis, as it improves diagnostic accuracy, reduces the negative appendicectomy rate and avoids unnecessary laparotomy.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Disease↗

Laparoscopic cholecystectomy and management of choledocholithiasis.

The advent of laparoscopic cholecystectomy (LC) has led to a reassessment of the approach to the management of choledocholithiasis. In a consecutive series of 418 patients undergoing LC, common bile duct (CBD) stones were suspected pre-operatively in 130 patients. Forty-five of the patients (35%) were found to have CBD stones on either pre-operative endoscopic retrograde cholangiopancreatography (ERCP; 20) or on operative cholangiography (OC; 25). Common bile duct stones were detected on OC in a further 12 of 288 patients (4.2%) without pre-operative suspicion of choledocholithiasis. Of the total of 57 patients with CBD stones, the duct was cleared by pre-operative ERCP and endoscopic sphincterotomy (ES) in 15 patients. In 13 patients, two of whom had had a pre-operative ERCP and ES, duct clearance was achieved by relaxing the sphincter pharmacologically and flushing the CBD via the OC catheter. One patient had an on-table ERCP and ES with successful stone extraction during LC. Eleven patients were converted to open operation with bile duct exploration. Sixteen patients had a postoperative ERCP. In five patients the CBD stones had passed spontaneously in the time between LC and ERCP. Ten patients required ES to clear the duct of stones. One patient had a failed ERCP and is still awaiting a repeat. The remaining patient was scheduled, but did not return for follow-up ERCP. In summary, pre-operative ERCP was indicated in less than 10% of patients in this series.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

Percutaneous cystogastrostomy for treatment of pancreatic pseudocysts.

Cystogastrostomy or cystojejunostomy at open operation has been the usual treatment for symptomatic pancreatic pseudocyst. The aim of this study was to assess prospectively the results of percutaneous cystogastrostomy (PCG) for the treatment of symptomatic pseudocysts. The technique of PCG comprised initially of drainage of the pseudocyst with a 10 Fr percutaneous, transgastric catheter. This initial drainage catheter had two components; the first, between the pseudocyst and the stomach, drained the pseudocyst and the second, between the stomach and exterior, acted as a percutaneous gastrostomy. The initial drain was left in situ for 14 days, at which time it was exchanged percutaneously for the definitive PCG; a double ended Mallecot type catheter that drained between the pseudocyst and the stomach. The latter catheter was left in situ until there was no residual pseudocyst demonstrated on computerized tomography scan and was removed endoscopically. Eleven patients with large (> 6 cm), symptomatic pseudocysts have been treated with PCG. All patients were treated successfully without the need for surgical intervention. The median time to radiological resolution was 24 days. There were four episodes of sepsis, two related to central venous line infections nad two related to catheter blockage. Percutaneous, cystogastrostomy blockage was managed by either replacing the initial drain or inserting a second catheter. The median follow up after successful treatment was 9 months (range 2-17). There were no symptomatic recurrences and one small (2 cm) asymptomatic recurrent pseudocyst. This preliminary experience with PCG demonstrates the efficacy of this procedure for treating symptomatic pancreatic pseudocysts.

Adult↗

Mechanisms underlying the antireflux action of fundoplication.

The effect of fundoplication on patterns of gastro-oesophageal reflux and the underlying motor mechanisms were investigated in 18 patients with symptomatic reflux. Oesophageal motility and pH were recorded concurrently after a standard meal. Studies were performed preoperatively and from 5 to 27 months after surgery. Fundoplication virtually eliminated reflux in all but three patients. Control of reflux was associated with a 50% fall in the number of transient lower oesophageal sphincter relaxations, a fall in the proportion of transient lower oesophageal sphincter relaxations accompanied by reflux from 47% to 17%, and an increase in the mean residual pressure at the gastro-oesophageal junction during swallow induced lower oesophageal sphincter relaxation from 0.7 mm Hg to 6.0 mm Hg. Basal pressure at the gastro-oesophageal junction rose from 10.9 mm Hg to 14.5 mm Hg, however, there was no correlation between postoperative reflux and basal gastro-oesophageal junction pressure. These findings suggest that the anti-reflux effects of fundoplication result from changes in the mechanical behaviour of the gastro-oesophageal junction that result in incomplete abolition of the high pressure zone during lower oesophageal sphincter relaxation, and reduced triggering of transient lower oesophageal sphincter relaxations.

Adult↗

Maxon is an optimal suture for bile duct anastomoses in pigs.

BACKGROUND: Three commonly used sutures were tested in a pig model of bile duct anastomosis to assess their relative contributions to inflammation and scarring. METHODS: Thirty pigs were randomised to bile duct division and anastomosis with either polyglyconate (Maxon), polyglactin 910 (Vicryl) or polypropylene (Prolene). Half the animals were sacrificed at two weeks and the remainder at 23 weeks. Anastomoses were assessed by cholangiography, scanning electron microscopy and light microscopy. RESULTS: There was less short term histological reaction with the two monofilament materials, Prolene and Maxon, compared to the braided suture Vicryl. Maxon was associated with less long term inflammation than Prolene, was found to handle better, and has an advantage over Prolene by being absorbable. CONCLUSION: Maxon is an optimal suture for bile duct anastomoses. Its long term absorption characteristics make it suitable for situations where bile duct healing may be delayed.

Anastomosis, Surgical↗

Structure and innervation of the extrahepatic biliary system in the Australian possum, Trichosurus vulpecula.

The morphology, microanatomy and innervation of the biliary tree of the Australian possum, Trichosurus vulpecula, was examined. The gross morphology of the gallbladder, hepatic and cystic ducts, and the course of the common bile duct, conforms to those of other species. The sphincter of Oddi has an extraduodenal segment that extends 15mm from the duodenal wall; within this segment the pancreatic and common bile ducts are ensheathed together by sphincter muscle. Their lumens unite to form a common channel within the terminal intraduodenal segment. Nerve cell bodies of the gallbladder were found in an inter-connecting network of ganglia that were located in the serosa, muscularis and mucosa. Nerve fibres innervated the muscle, arterioles and the mucosa. Few ganglia were found along the supra sphincteric portion of the common bile duct. Nerve trunks followed the duct and a dense nerve fibre plexus was found in the mucosa. In the sphincter most ganglia were located in two plexuses, the first between the layers of the external sphincter muscle, which was continuous with the external muscle of the duodenum, and the second was associated with the internal sphincter muscle. Nerve fibres were numerous in the sphincter muscle, and were also found in the subepithelial and periglandular plexuses of both the pancreatic and common bile ducts.

Animals↗

Effects of halothane anesthesia on the motility of the sphincter of Oddi and transsphincteric flow in Australian brush-tailed possums.

We evaluated the effect of halothane anesthesia on the motility of the sphincter of Oddi and simultaneous transsphincteric flow in Australian Brush-tailed possums (Trichosurus vulpecula). Halothane levels in the range of 0.25 to 2% were administered and decreased transsphincteric flow in a dose-dependent manner. Sphincter of Oddi basal pressure was higher than normal, but not in a dose-dependent manner. Additionally, halothane anesthesia influenced the sphincter of Oddi motility by decreasing the motility index (mean amplitude multiplied by frequency of contractions). This decrease was dose dependent. These findings indicate that sphincter of Oddi basal pressure is a major component of sphincter of Oddi motility responsible for regulating transsphincteric flow in this species. For studies of the sphincter of Oddi motility in anesthetized Australian Brush-tailed possums, we recommend anesthetic induction with ketamine (50 mg/kg, i.m.) and the inspired halothane level should not exceed 0.75% during the study period, as the effects we have demonstrated were most evident at levels greater than 0.75%. If higher halothane levels are required to maintain satisfactory anesthesia, an alternative anesthetic agent should be considered.

Animals↗

Erythromycin and motilin stimulate sphincter of Oddi motility and inhibit trans-sphincteric flow in the Australian possum.

The actions of erythromycin lactobionate and porcine motilin on trans-sphincteric flow and simultaneous sphincter of Oddi motility were studied in 15 anaesthetized Australian Brush-tailed possums (Trichosurus vulpecula). Erythromycin (25-200 micrograms/kg) and motilin (25-200 ng/kg) were administered as graded doses by close intraarterial injection. Trans-sphincteric flow was measured as inflow and outflow. Both motilin and erythromycin decreased trans-sphincteric inflow (both P < 0.0001) and outflow (P < 0.0001 and P = 0.0017 respectively) in a dose-dependent manner. The highest dose of each agent abolished trans-sphincteric flow. These agents increased sphincter of Oddi phasic contraction frequency and basal pressure up to 2 and 3 fold respectively (P < 0.05). The amplitude of the sphincter of Oddi phasic contractions were not influenced in any consistent fashion by either agent. The durations of the responses (trans-sphincteric inflow) elicited by erythromycin and motilin were dose dependent (P = 0.0225 and P = 0.0001 respectively). The actions of erythromycin (200 micrograms/kg) or motilin (100 ng/kg) on trans-sphincteric flow and sphincter of Oddi motility were not influenced by neural blockade with tetrodotoxin. These findings support the hypothesis that erythromycin acts as a motilin agonist and both substances increase the resistance to flow through the sphincter of Oddi by raising the basal pressure and frequency of contractions.

Animals↗

Motilin and erythromycin enhance the in vitro contractile activity of the sphincter of Oddi of the Australian brush-tailed possum.

Erythromycin has been shown to interact with gastrointestinal smooth muscle in a similar manner to motilin, and has been postulated as a motilin receptor agonist. We report that in isolated preparations from the biliary tract of thirty one Australian Brush-tailed Possums (Trichosurus vulpecula) erythromycin acts in a similar manner to motilin. In all muscle strips from the sphincter of Oddi, prepared in both the circular and longitudinal orientation, both synthetic porcine motilin (10(-10) M-10(-6) M) and erythromycin (lactobionate) (10(-8) M-10(-4) M) stimulated contractile activity in a concentration dependent manner, via a direct effect on the smooth muscle (the response was unaffected by tetrodotoxin, omega conotoxin GVIA or atropine). In strips prepared from the gallbladder neither agonist affected the contractile activity in 7 of 8 animals. Motilin was approximately 1000 fold more potent in stimulating contractile activity than erythromycin in both sphincter of Oddi circular strips [pD2 for peak response to motilin 8.67 (mean) +/- 0.06 (SEM) compared with erythromycin 5.67 +/- 0.09] and sphincter of Oddi longitudinal strips [pD2 for peak response to motilin 8.64 (mean) +/- 0.28 (SEM) compared with erythromycin 5.45 +/- 0.23]. The concentration response curves for motilin and erythromycin were similar and both agonists required the presence of extracellular calcium to elicit responses (responses were diminished by verapamil and abolished in calcium free Krebs solution). Our results support the hypothesis that erythromycin mimics the action of motilin in stimulating the sphincter of Oddi in vitro.

Animals↗