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Biomedical subjects

T N Pappas

Publications and source records attributed to T N Pappas.

118 records · Page 7Linked to original sources

Corticotropin-releasing factor inhibits gastric emptying in dogs: studies on its mechanism of action.

The effects of corticotropin-releasing factor (CRF) on gastric emptying of a saline solution was further investigated in six dogs prepared with gastric fistulas and chronic cerebroventricular guides and in four other dogs with chronic gastric fistulas and pancreatic (Herrera) cannulas. Intravenous infusion of CRF significantly inhibited gastric emptying whereas intracerebroventricular injection of CRF had no effect. Pharmacologic blockade of beta-adrenergic system by propranolol did not modify intravenous CRF induced delay in gastric emptying. Intravenous CRF did not influence basal pancreatic secretion whereas secretin infused stimulated bicarbonate secretion. These results indicate that intravenous but not intracerebroventricular administration of CRF inhibited gastric emptying of a saline solution in dogs. The inhibitory effect of intravenous CRF on gastric emptying is not mediated by the beta-adrenergic nervous system, and not secondary to the release of other peptides that affect both pancreatic secretion and gastric emptying such as cholecystokinin and peptide YY.

Animals↗

Staging of pancreatic cancer before and after neoadjuvant chemoradiation.

Neoadjuvant chemoradiation therapy is used at many institutions for treatment of localized adenocarcinoma of the pancreas. Accurate staging before neoadjuvant therapy identifies patients with distant metastatic disease, and restaging after neoadjuvant therapy selects patients for laparotomy and attempted resection. The aims of this study were to (1) determine the utility of staging laparoscopy in candidates for neoadjuvant therapy and (2) evaluate the accuracy of restaging CT following chemoradiation. Staging laparoscopy was performed in 98 patients with radiographically potentially resectable (no evidence of arterial abutment or venous occlusion) or locally advanced (arterial abutment or venous occlusion) adenocarcinoma of the pancreas. Unsuspected distant metastasis was identified in 8 (18%) of 45 patients with potentially resectable tumors and 13 (24%) of 55 patients with locally advanced tumors by CT. Neoadjuvant chemoradiation therapy and restaging CT were completed in a total of 103 patients. Thirty-three patients with potentially resectable tumors by restaging CT underwent surgical exploration and resections were performed in 27 (82%). Eleven (22%) of 49 patients with locally advanced tumors by restaging CT were resected, with negative margins in 55%; the tumors in these 11 patients had been considered locally advanced because of arterial involvement on restaging CT. Staging laparoscopy is useful for the exclusion of patients with unsuspected metastatic disease from aggressive neoadjuvant chemoradiation protocols. Following neoadjuvant chemoradiation, restaging CT guides the selection of patients for laparotomy but may overestimate unresectability to a greater extent than does prechemoradiation CT.

Adenocarcinoma↗

The role of laparoscopy in the management of suspected pancreatic and periampullary malignancies.

Laparoscopic evaluation of patients with suspected periampullary malignancies has been utilized more frequently in recent years. Its exact role with regard to staging and surgical bypass for palliation have yet to be clearly defined. To better define the role of laparoscopy in the evaluation and palliation of periampullary malignancy, a retrospective review of the Duke experience was carried out. Fifty-three patients with suspected pancreatic or periampullary malignancies were referred for surgical evaluation at Duke University Medical Center between 1993 and 1995. All patients underwent CT scanning and lesions were classified as resectable or unresectable based on previously established criteria. Patients either underwent laparoscopic evaluation (n = 30; 11 with laparoscopic palliation) or proceeded directly to celiotomy (n = 23). Charts were reviewed for postoperative course including complications, length of stay, and hospital costs. Although laparoscopy had a sensitivity of 93.3% for metastatic disease, CT scans accurately staged 86.8% of patients missing only one patient with peritoneal/hepatic disease. Based on these results, laparoscopy may not be beneficial for every patient with a suspected pancreatic malignancy. Retrospectively an attempt was made to determine which patients benefited from laparoscopy and which patients are best served by proceeding directly to open exploration. From these data we devised an algorithm that outlines an efficient and cost-effective approach for this patient population.

Adult↗

CT of fundoplication.

To determine the CT findings postfundoplication, we retrospectively compared CT in 22 postfundoplication patients with CT in 22 patients with unrepaired hiatal hernias and gastroesophageal (GE) junction abnormalities and 24 patients with gastric or esophageal carcinoma involving the GE junction. Seventeen of the 22 postfundoplication patients had undergone a Nissen procedure. Of the 22 patients, 11 had esophageal dilatation, 14 had GE junction masses, 4 had esophageal wall thickening, 7 had surgical clips, and none had hepatic metastases or upper abdominal lymphadenopathy. Statistically, on CT, postfundoplication patients are more likely to have a GE junction mass (p = 0.023) and least likely to have wall thickening (p = 0.021). Nonetheless, because the findings occur frequently in each group, they are not diagnostic in the individual patient. However, 11 of 12 post-Nissen masses had the unique finding of an oval or linear central fat density within the mass. This finding was absent in the other postfundoplication masses and in those patients with repaired hiatal hernia or tumor. We conclude that pseudomasses occur on CT postfundoplication and can be indistinguishable from hiatal hernias and GE junction neoplasms unless a central fat density is present.

Adult↗

Pancreatitis complicated by gland necrosis: evolution of findings on contrast-enhanced CT.

PURPOSE: The purpose of this work was to investigate the natural history of pancreatic necrosis on contrast-enhanced CT in patients managed nonoperatively. METHOD: A computer-based radiology information search revealed 32 patients with pancreatic necrosis who had had serial contrast-enhanced CT scans and were managed nonoperatively. There were 23 men and 9 women with a mean age of 51 years. One hundred forty-five contrast-enhanced CT scans were retrospectively reviewed for the location and extent of necrosis. The medical records of all patients were reviewed. RESULTS: The 32 patients had a mean Ranson clinical grade of 5.8 (range 3-8). Eighteen of these 32 patients were managed nonoperatively, and 14 patients required a necrosectomy after initial nonoperative management. In the 32 patients, the location of necrosis was in the head (3), body (6), tail (2), head/body (2), head/body/tail (9), body/tail (9), and head/tail (1). Extent of necrosis was 0-25% (9), 26-50% (6), 51-75% (6), and 76-100% (11). The extent of necrosis remained stable during follow-up in 22 (69%) patients and increased during follow-up in 10 (31%). Necrosectomy was performed in six (60%) patients in whom there was an increase in necrosis and eight (36%) patients in whom necrosis was stable. No patient had restoration of normal enhancement in an area that was previously necrotic. There were five patients who were managed nonoperatively (mean follow-up 318 days) in whom the necrosis eventually resorbed, forming a focal parenchymal cleft reminiscent of a scar. Five of the 32 patients died. CONCLUSION: Pancreatic necrosis as demonstrated by CT tends to remain stable in most patients treated nonoperatively. If the extent of necrosis increases, patients are more likely to require a necrosectomy. In some patients managed nonoperatively, the pancreatic necrosis will resorb, resulting in a fat-replaced cleft reminiscent of a scar.

Adult↗

Suction sclerotherapy for the treatment of esophageal varices: a report of a preliminary feasibility study.

We report a new treatment modality for esophageal varices, suction sclerotherapy, which was designed to lift away mucosa and submucosa during treatment to prevent deep injection and resultant esophageal ulcerations. In order to compare the posttreatment complications of suction sclerotherapy against freehand sclerotherapy, we randomized 4 mongrel dogs to receive ten injections of 0.5-ml aliquots of absolute alcohol into the esophagus by either the suction or freehand sclerotherapy technique. The animals were humanely sacrificed after 48 h and examined. A total of five large, deep, confluent ulcers, free perforation, and lung abscess were seen in the animals randomized to freehand sclerotherapy. In contrast, a total of 14 shallow, discrete, erythematous lesions were found in the suction sclerotherapy group; none of these lesions extended deeper than the submucosa. We conclude that suction sclerotherapy produced local complications limited to the submucosa which were less severe as compared with freehand sclerotherapy.

Animals↗

Management of biliary complications after heart transplantation.

BACKGROUND: Immunosuppression increases the risk of biliary complications in heart transplant recipients. METHODS: Patients undergoing heart transplantation since 1986 who were at risk for cholelithiasis (n = 60) were retrospectively studied. RESULTS: Cholestatic jaundice developed in all patients after the operation because of biliary obstruction from cholelithiasis, cyclosporine toxicity, Imuran toxicity, or Gilbert's disease. The incidence of cholelithiasis or sludge was 42% (n = 25 of 60). Gallstones developed within 1.8 +/- 1.1 years in 17% of patients (n = 8 of 48) with a normal pretransplantation ultrasonogram. Biliary colic or gallstone pancreatitis developed 2 +/- 1.2 years after transplantation in 58% of patients (n = 7 of 12) with asymptomatic gallstones diagnosed before transplantation. The overall incidence of cholecystectomy or cholecystectomy with Roux-en-Y cystojejunostomy was 40% (n = 24). Both open cholecystectomy (n = 5) and laparoscopic cholecystectomy (n = 19) were performed without significant complications. Recovery is significantly more rapid (p < 0.05) after laparoscopic cholecystectomy versus open cholecystectomy (1 week versus 3 weeks). CONCLUSIONS: This analysis indicates that transplant candidates who have gallstones on pretransplantation evaluation or in whom gallstones develop after transplantation should undergo laparoscopic cholecystectomy at the earliest time in their posttransplantation course (i.e., 3 months) regardless of their symptomatic status. Removal of the diseased gallbladder not only simplifies the evaluation of cholestatic jaundice by eliminating the need for multiple ultrasonograms to exclude acute cholecystitis or choledocholithiasis but also safely minimizes the risk of the development of severe biliary complications.

Adolescent↗

Laparoscopic fundoplication: an alternate approach in the surgical treatment of esophageal reflux (continuing education credit).

1. Laparoscopic fundoplication is more "patient friendly" than the comparable open procedure, affording shorter postoperative recovery and faster return of the patient to normal activity. 2. Laparoscopic fundoplication achieves the same results and is essentially the same procedure as open fundoplication, but with smaller incisions and less pain. 3. The procedure takes time to learn, but once mastered, it cuts the OR time to approximately the same as for the open fundoplication.

Education, Nursing, Continuing↗