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Biomedical subjects

K W O'Connor

Publications and source records attributed to K W O'Connor.

At least 19 recordsLinked to original sources

ERCP recycling.

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Cholangiopancreatography, Endoscopic Retrograde↗

Patents for genetically modified animals.

Should genetically engineered animals be patented? This issue has been one of the most contentious as lawmakers have grappled with how best to protect intellectual property. Since the 1980 case of Diamond v. Chakrabarty, in which the U.S. Supreme Court ruled that a living microorganism is patentable, the U.S. Patent and Trademark Office has determined that plants and nonhuman animals can be patented. These policy decisions have led to congressional debate on whether animals should be patentable subject matter. Patenting of living organisms is unique for three reasons: the invention itself is alive; the invention in some instances can reproduce itself; and the invention sometimes cannot be adequately described for patent specification purposes, leading to the need for deposit of the invention for patent purposes.

Animals↗

Crohn disease of the small intestine: accuracy and relevance of enteroclysis.

The accuracy and clinical relevance of enteroclysis in the evaluation of 138 patients referred for enteroclysis for suspected Crohn disease of the small intestine are reported. The original prospective interpretations of enteroclysis results were assessed after a clinical follow-up period of 2 or more years. With all patients considered, enteroclysis had a sensitivity, specificity, and accuracy of 100%, 98.3%, and 99.3%, respectively, with only one false-positive diagnosis and no false-negative diagnoses. Thirty-one percent (n = 43) of the patients had lesions of early Crohn disease. All patients who required surgery (n = 23) had advanced lesions of the disease, according to enteroclysis criteria. Clinical evidence of Crohn disease did not develop in the 58 patients in whom enteroclysis revealed no abnormality. There were no complications related to the procedure. It is concluded that enteroclysis is an accurate method for diagnosis and exclusion of Crohn disease of the small intestine and provides detailed structural information relevant to appropriate management of the disease.

Adolescent↗

Patenting life.

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Animals↗

Frequency of abnormal sphincter of Oddi manometry compared with the clinical suspicion of sphincter of Oddi dysfunction.

Patients with pancreaticobiliary pain or idiopathic pancreatitis have been classified as having definitive (type I), presumptive (type II), or possible (type III) sphincter of Oddi dysfunction (SOD) based on clinical, laboratory, and ERCP data. This study was undertaken to determine the frequency of abnormal sphincter of Oddi manometry (SOM) when patients are classified by this system. Two hundred and thirteen patients with pancreaticobiliary pain were evaluated clinically; SOM, ERCP, and ductal contrast drainage time tests were performed. For biliary types I, II, and III, the frequency of abnormal SOM was 85.7%, 55.1%, and 28.1%, respectively. Similarly, for pancreatic types I, II, and III, an elevated basal sphincter pressure occurred in 92.3%, 58.2%, and 35.1%, respectively. When patients with an abnormal basal sphincter pressure were characterized by the magnitude of the elevation, the manometric profiles were similar for types I, II, and III. These data suggest that elevated sphincter pressure occurs more frequently in type III patients than previously reported, and supports consideration of SOM when evaluating and treating type II and type III patients.

Adolescent↗

Flexible sigmoidoscopy plus air contrast barium enema versus colonoscopy for suspected lower gastrointestinal bleeding.

A randomized, controlled trial was performed to compare the diagnostic yields and cost-effectiveness of two strategies for the evaluation of nonemergent lower gastrointestinal bleeding. Three hundred eighty patients aged greater than or equal to 40 yr were randomized to undergo initial flexible sigmoidoscopy plus air contrast barium enema or colonoscopy; 332 completed the initial studies. Initial colonoscopy detected more cases of polyps less than 9 mm in size, adenomas, and arteriovenous malformations but fewer cases of diverticulosis. No significant difference was found between strategies in the number of patients detected with cancers or polyps greater than or equal to 9 mm in size. In both strategies, cancers were more common in subjects aged greater than or equal to 55 yr (8% overall) than in those aged less than 55 yr (1%). Among patients aged less than 55 yr with suspected lower gastrointestinal bleeding, initial flexible sigmoidoscopy plus air contrast barium enema is a more cost-effective strategy for the detection of colonic neoplasms than initial colonoscopy. However, initial colonoscopy is more cost effective for those aged greater than or equal to 55 yr.

Barium Sulfate↗

Cholecystocolonic fistula: malabsorptive consequences of lost bile acids.

A patient with the painless onset of a cholecystocolonic fistula associated with virtually complete common bile duct obstruction due to stones provided a unique opportunity to assess the consequences of prolonged bile acid depletion on the digestion and absorption of nutrients. Over 2 years, the patient insidiously developed steatorrhea, osteomalacia with an atraumatic pelvic fracture, and congestive heart failure complicated by polymorphic ventricular tachycardia (torsade de pointes) all of which could be attributed to malabsorption of fat and fat-soluble vitamins.

Aged↗

Comparison of three nonsurgical treatments for bleeding esophageal varices.

Ninety-seven patients with recent or active variceal bleeding were randomly assigned to oral propranolol, endoscopic sclerotherapy plus oral propranolol, or transhepatic sclerotherapy plus oral propranolol. The effects of treatment on the number of units transfused, rebleeding of any magnitude, major rebleeding, and death were assessed in these patients, 82% of whom were alcoholic and 81% Child's Class C. After a minimum follow-up interval of 2 yr (range, 27-65 mo), major rebleeding rates were 65% for propranolol alone, 45% for endoscopic sclerotherapy plus propranolol, and 60% for transhepatic sclerotherapy plus propranolol. The corresponding death rates were 81% for propranolol alone, 55% for endoscopic sclerotherapy plus propranolol, and 66% for transhepatic sclerotherapy plus propranolol (p = 0.03). Thirty-three patients (34%) never received propranolol; 8 due to medical contraindications and 25 because they died or bled enough to meet the definition of treatment failure within 3 or 4 days of randomizations (no significant differences among treatment groups). Patients assigned to propranolol alone bled sooner, bled more units, and had a higher mortality rate than patients treated by endoscopic sclerotherapy plus propranolol. Patients treated with transhepatic sclerotherapy plus propranolol had intermediate results. Propranolol alone is inadequate treatment for esophageal variceal bleeding in patients with advanced liver disease.

Blood Transfusion↗

The yield of routine duodenal aspiration for Giardia lamblia during esophagogastroduodenoscopy.

Giardia lamblia, the most common intestinal parasite in the United States, may present with nonspecific gastrointestinal symptoms when the infection is chronic. In order to determine how frequently the parasite could be detected in patients undergoing endoscopy for standard indications, duodenal aspirates were collected from 144 patients. Despite G. lamblia being endemic in the state (and therefore readily recognized in our laboratory), there was only one positive aspirate in the 144 specimens collected (0.7%) at this midwestern, tertiary care facility servicing a primarily middle class population. In the population sampled, routine duodenal aspiration for G. lamblia in patients not clinically suspected of having this parasitic infection is of very low yield.

Adolescent↗

Training resident physicians in fiberoptic sigmoidoscopy. How many supervised examinations are required to achieve competence?

Twenty-five resident physicians performed 495 fiberoptic sigmoidoscopic examinations that were graded for overall skill according to a six-point competence scale. In general, 24 to 30 examinations were required to become competent at fiberoptic sigmoidoscopy. Trainees with prior rigid sigmoidoscopy experience achieved competence more quickly than those with no prior rigid sigmoidoscopy experience. As experience increased, unassisted insertion distance and luminal visualization increased, insertion time and assisted time decreased, and management scores and percent correct diagnoses improved. Trainees detected 93 to 100 percent of polyps and cancers viewed by the experienced sigmoidoscopist once competence was achieved. These data indicate that programs for training primary care physicians in fiberoptic sigmoidoscopy are feasible, help define the number of examinations required to become competent, and indicate that such trainees should be effective in cancer screening.

Clinical Competence↗

Portal hypertension due to jejunal vascular malformation.

We report a case of hepatic portal venous hypertension secondary to a small-bowel vascular malformation in a 24-year-old man with anemia. Preoperative diagnostic evaluation included gastrointestinal barium studies and endoscopy (showing esophageal varices), hepatic panangiography, peroral small-bowel biopsy, percutaneous transhepatic portal venography, and manometry. Preoperative injection of methylene blue dye into the jejunal arteries supplying the malformation resulted in easy localization of the lesion at surgery. Direct manometry at the time of segmental jejunal resection yielded a portal pressure of 35 mmHg, with subsequent reduction to 21 mmHg.

Adult↗

An improved technique for accessory papilla cannulation in pancreas divisum.

Cannulation of the accessory papilla with dorsal pancreas ductography was accomplished in 13 of 15 consecutive cases of pancreas divisum. When routine cannulation of the main pancreatic papilla fails to produce a pancreatogram or yields only a ventral pancreas, the use of intravenous secretin and a 23-gauge needle catheter is recommended to facilitate accessory duct cannulation.

Adult↗

Ethanol thrombotherapy of esophageal varices: further experience.

Fifty patients with liver cirrhosis (13 Child class B, 37 class C) were treated for variceal hemorrhage during a 3-year period using the transhepatic selective catheterization and injection of absolute ethanol. Technical failure of the procedure was encountered in 13 instances. The causes were the presence of massive ascites and rigidly contracted liver, cavernous transformation of the main portal vein, and severe coagulopathy. Of the 13 failures, 12 were in Child class C and one in class B. Of 37 initially successfully treated patients, 13 rebled subsequently. Nine of these were Child class C and four were class B. Rebleeding was fatal in five of nine class C patients. Rebleeding was due to recanalization of previously thrombosed access channel in two of 13 patients. Nine patients died, despite successful thrombosis of varices, due to underlying medical conditions. Fifteen patients survived 6 months or more after initial thrombosis without rebleeding. Child class B patients are better candidates for this treatment technique because more favorable treatment results are expected in them. Child class C patients with massive ascites and severely contracted and rigid liver pose a significant technical challenge, but in about one-third, successful control of variceal bleeding can be achieved. Most of those who survived more than 6 months showed varying degrees of improvement in clinical signs and symptoms.

Adult↗