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Biomedical subjects

S E Silvis

Publications and source records attributed to S E Silvis.

At least 19 recordsLinked to original sources
PubMed1990

In vivo evaluation of monopolar versus bipolar electrosurgical polypectomy snares.

The energy required and tissue damage in bipolar and monopolar polypectomy snares were compared in a canine model. The bipolar snare required an average of 34 joules of energy, whereas the monopolar snare required 228 joules to cut the same diameter of gastric mucosa tended into a polypoid structure (p = 0.0005). The reduced energy delivered to the tissue from the bipolar procedure resulted in only 32% average depth of damage to the underlying gastric wall, whereas the monopolar procedure caused an average 69% (p = 0.001). Surgically created polyps required 247 joules and 69 joules for corresponding monopolar and bipolar polypectomy (p = 0.001). The decreased energy required and the correspondingly reduced damage caused to the underlying bowel wall by the bipolar snare should reduce the incidence of perforation and post-polypectomy syndrome. The bipolar snare completes a local circuit about the snare, eliminating the return electrode and, consequently, the possibility of any return electrode burns. The bipolar snare thus provides an added safety margin during polypectomy.

Animals↗
PubMed1989

Pancreatic pseudocysts: clinical and endoscopic experience.

Records of 51 patients with proven pancreatic pseudocyst (PC) were retrospectively reviewed to assess clinical and endoscopic variables. Thirty-nine had surgery after preoperative endoscopic retrograde cholangiopancreatography (ERCP), six patients had ERCP only, and six patients had surgery without prior ERCP. Forty-two pancreatograms were obtained, and all were abnormal. PC communication with the pancreatic duct was present in 29 and ductal obstruction downstream from the PC was shown in 11 studies. Thirty-five cholangiograms were obtained and 19 were abnormal, including ductal narrowing in 16 and biliary calculi in three. PC contents were cultured intraoperatively in 29 patients, and 17 were positive. PC infection was highly correlated with the incidence of recurrent hospitalizations and with PC recurrence. PC infection did not occur significantly more often in patients with communicating PC or in those with preoperative ERCP. Factors that did not influence outcome included PC size, multiplicity, anatomic location, and PC communication with the pancreatic duct. Results from both ERCP and culture of PC contents add significantly to our knowledge of PC disease.

Adult↗
PubMed1988

Effect of bombesin and gastrin-releasing peptide on canine sphincter of Oddi.

This study reports the effects of bombesin and gastrin-releasing peptide (GRP) on the canine sphincter of Oddi using a method that allows repeated cannulation of the biliary sphincter in the unanesthetized animal through a Thomas cannula placed opposite the biliary papilla. Immediately after intravenous administration of bombesin or GRP, phasic sphincter contractions disappeared, basal sphincter pressures fell, and common bile duct pressures rose. Because bombesin releases cholecystokinin (CCK) and CCK resulted in a similar pattern to that of bombesin, the bombesin effect on the sphincter of Oddi may have been secondary to CCK's effect on the sphincter. To test if the bombesin effect on the sphincter of Oddi was due to the release of CCK, we blocked CCK release by administration of somatostatin, having first established that somatostatin blocked endogenous CCK release in our animal model by use of an intraduodenal infusion of lipid. Exogenous administration of bombesin failed to alter sphincter of Oddi or common bile duct pressures in dogs treated with somatostatin. Somatostatin did not, however, block CCK's effect on gallbladder contraction, since exogenous administration of CCK after somatostatin injection resulted in the pressure changes in the biliary tree typical of CCK-induced gallbladder contraction. Thus bombesin administration appears to result in sphincter relaxation and gallbladder contraction by the release of endogenous CCK rather than by a direct effect. The increase in common bile duct pressures was due to gallbladder contraction, since this rise in pressure was abolished by cholecystectomy. The peptide effect on sphincter contraction and basal sphincter pressure were unaffected by cholecystectomy.

Ampulla of Vater↗
PubMed1987

Pseudomonas infection of the biliary system resulting from use of a contaminated endoscope.

Pseudomonas aeruginosa was present in bile cultures from 10 patients who had undergone previous endoscopic retrograde cholangiopancreatography in 1984. After environmental cultures and review of instrument disinfection, we traced the infections to a single endoscope contaminated with P. aeruginosa, serotype 10. Although the instrument had been cleaned repeatedly with an automatic endoscope cleaning machine, P. aeruginosa survived on residual moisture left in the channels of the endoscope. Contamination ended only after we began to manually suction alcohol through the endoscope before air drying. In 5 of 10 patients, P. aeruginosa caused clinical infections including gangrenous cholecystitis, abscesses, and death. We could identify no factor that distinguished symptomatic from asymptomatic patients. In asymptomatic patients, P. aeruginosa was recovered from gallbladder bile up to 2 mo after endoscopic retrograde cholangiopancreatography. As this P. aeruginosa epidemic was discovered retrospectively because we monitor bile cultures, we advocate this practice as part of endoscopic retrograde cholangiopancreatography procedures.

Bile↗
PubMed1987

Portal vein thrombosis following combined endoscopic variceal sclerosis and vasopressin therapy for bleeding varices.

We report the occurrence of acute portal vein thrombosis in three patients undergoing endoscopic variceal sclerosis (EVS) for bleeding esophageal varices. All patients received intravenous vasopressin in close proximity to or at the time of EVS. By increasing flow of sclerosant caudally into gastric veins during EVS, vasopressin may predispose to retrograde propagation of thrombus into the portal venous system. Combined use of vasopressin and EVS for treatment of bleeding esophageal varices should be undertaken with caution.

Acute Disease↗
PubMed1985

Final report on the United States Multicenter Trial comparing ranitidine to cimetidine as maintenance therapy following healing of duodenal ulcer.

Patients with recently healed duodenal ulcers were enrolled at 14 participating centers in a 12-month study comparing the effectiveness of ranitidine and cimetidine, two H2-receptor blockers, for maintenance therapy. Patients were randomly assigned to take bedtime doses of 150 mg of ranitidine (n = 60) or 400 mg of cimetidine (n = 66). Endoscopic examinations were scheduled at baseline and after 4, 8, and 12 months of therapy, or when symptoms compatible with active ulcer disease developed. Life-table analysis indicated a relapse rate of 16% for the ranitidine subjects and 43% for the cimetidine subjects during the 12-month period (p = 0.01). Therapy was discontinued in one ranitidine subject and two cimetidine subjects for adverse events considered drug-related. There were no drug-related laboratory abnormalities in either treatment group. No significant drug-related adverse effects were seen with either drug during this 1-year trial. At the doses prescribed, ranitidine was superior to cimetidine as maintenance therapy in duodenal ulcer disease.

Cimetidine↗
PubMed1985

Sodium morrhuate stimulates granulocytes and damages erythrocytes and endothelial cells: probable mechanism of an adverse reaction during sclerotherapy.

Stimulated by a patient with dyspnea, thrombocytopenia, and leukopenia after sodium morrhuate sclerotherapy, we studied the effect of this agent on the plasma coagulation and complement systems, the formed elements of the blood, and cultured human endothelial cells. The addition of sodium morrhuate to citrated plasma did not cause clotting or shorten the prothrombin time or partial thromboplastin time. Incubation of a 1:100 dilution of the clinical sodium morrhuate preparation in heparinized plasma led to a modest rise in [C3a]. The addition of the drug (dilutions 1:50 to 1:300) to granulocytes caused prompt aggregation (and, at the higher concentrations, granulocyte cytotoxicity [trypan blue exclusion; lactate dehydrogenase release]), but the same dilutions failed to aggregate platelets. However, 0.05% morrhuate added to washed red blood cells caused a prompt 84.0% (+/- 0.8% SEM) hemolysis, rendering the supernatant buffer a potent platelet aggregant. Not only was this sclerosing agent toxic to granulocytes and red cells, but a 1:1000 dilution of the drug also caused the destruction of 35.5% (+/- 6.6%) of cultured endothelial cells as measured by chromium 51 release. Three other agents in current use (ethanolamine oleate, sodium tetradecyl sulfate, and polidocanol) were studied and found to cause effects qualitatively similar to those of sodium morrhuate. We conclude that these drugs cause phlebosclerosis not primarily through induction of plasma coagulation, but by directly damaging endothelium and red cells, triggering platelets, and aggregating granulocytes at the venous wall endothelium. These effects likely derive from the surfactant properties of sodium morrhuate as well as its high arachidonate content.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Coagulation↗
PubMed1979

Gastrinoma associated with common bile duct obstruction and the ectopic production of ACTH.

A case of adrenocortical hyperfunction due to ectopic production of ACTH by a gastrin-producing tumor of the pancreas is described. Cushing's syndrome preceded the appearance of the overt Zollinger-Ellison syndrome by 2 years and was treated by bilateral adrenalectomy. The Zollinger-Ellison syndrome was initially treated with cimetidine, which successfully reduced the secretion of gastric acid. Because the pancreatic gastrinoma continued to grow, causing obstruction of the common bile duct, biliary diversion and total gastrectomy were performed. There is evidence that the pancreatic gastrinoma was the source of the ectopic production of ACTH and possibly secretion. The role of Histamine-2 blocking agents as therapy in the Zollinger-Ellison syndrome is discussed.

Adrenocorticotropic Hormone↗
PubMed1979

Significance of the nonopacified gallbladder in endoscopic retrograde cholangiography.

Failure to visualize the cystic duct and gallbladder during endoscopic retrograde cholangiography, while obtaining satisfactory opacification of the rest of the biliary system, is a radiographic sign of undetermined meaning. The diagnostic implication of this finding was analyzed in 63 patients with pathologically proven diagnoses. One patient was normal at surgery. Three groups of abnormal patients had: (1) obstructing lesions of the distal common bile duct (35 patients); (2) primary lesions of the cystic duct or gallbladder (19 patients); or (3) obstructing lesions about the common hepatic/cystic duct junction (8 patients). The results indicate that obstructing lesions of the distal common bile duct may cause stasis of bile within the biliary system, increased biliary pressure, and sludge formation that prevent the flow of contrast material through the cystic duct and into the gallbladder, which can cause nonopacification. If the extrahepatic biliary system is of normal caliber without evidence of an obstructing process, nonfilling of the cystic duct and gallbladder is highly predictive of pathology.

Biliary Tract Diseases↗
PubMed1978

The normal cholangiogram.

This paper describes the measurements of the normal cholangiogram as demonstrated by endoscopic retrograde cholangiopancreatography. Two groups of patients were studied. There were 49 patients who had normal livers and no evidence of biliary tract disease. In addition, there were 25 patients with known liver disease and an apparent normal extra-hepatic biliary tract. The extrahepatic bile duct was measured in three regions: (1) the common hepatic duct (above the cystic duct and below the bifurcation); (2) the prepancreatic portion (below the cystic duct and above the pancreas); and (3) the interpancreatic portion (bile duct within the pancreas). These measurements ranged from 2.1 to 9.2 mm. Although the common bile ducts were generally quite uniform in caliber, there were instances where each portion was the largest diameter in an individual case. There was slight increase in bile-duct caliber with age. This study showed somewhat smaller measurements than previously reported and may relate to case selection in this or previous studies.

Adolescent↗
PubMed1978

Cholangiographic abnormalities in patients with inflammatory bowel disease.

Twenty patients with inflammatory bowel disease, abnormal liver function tests and abnormal endoscopic retrograde cholangiograms were found to have a spectrum of abnormalities affecting the intra- and extrahepatic biliary trees. The intrahepatic systems were abnormal in all patients and demonstrated ductal stenosis, ectasia, decreased arborization and major duct obstruction. The extrahepatic systems were abnormal in 75 percent of cases with stenosis, diverticula formation and mural irregularity being the most frequent abnormalities. The value of endoscopic retrograde cholangiography in this patient group is to exclude extrahepatic obstruction, establish a nonoperative diagnosis, and assist in determining the method of treatment.

Adenoma, Bile Duct↗
PubMed1978

The treatment of hemorrhagic gastritis with cimetidine.

Thirteen patients in whom bleeding from hemorrhagic gastritis was not controlled by a variety of therapeutic modalities were treated with cimetidine. Twelve of the 13 patients stopped bleeding. Three subsequently rebled, two of whom required an operation to control the bleeding. The average amount of blood transfused per patient before treatment with cimetidine was 16 units and after cimetidine, 1.6 units. Nine of the 13 patients died, but only one of them died of hemorrhage. The remaining eight patients died of a combination of sepsis and multiple organ failure. We observed no adverse side-effects after the administration of cimetidine. Cimetidine is a safe and reliable means to control bleeding from hemorrhagic gastritis. Once the diagnosis of hemorrhagic gastritis is established, treatment with cimetidine should be begun and continued until the underlying stress which initiated the bleeding is controlled.

Cimetidine↗