Faculty Bibliography

Endoscopically placed biliary stents have supplanted surgical decompression as the preferred treatment option for patients with obstructive jaundice from advanced pancreatic cancer. An unusual complication of indewelling biliary stents is duodenal perforation into the retroperitoneum. We describe the case of a patient with end-stage pancreatic cancer who presented with an acute abdomen from erosion of a previously placed bile duct stent through the wall of the second portion of the duodenum. Although our patient presented with advanced symptoms, clinical presentations can vary from mild abdominal discomfort and general malaise to overt septic shock. Definitive diagnosis is best made with computed tomography (CT) imaging, which can detect traces of retroperitoneal air and fluid. Treatment options vary from nonoperative management with antibiotics, bowel rest, and parenteral alimentation in the most stable patients to definitive surgery with complete diversion of gastric contents and biliary flow from the affected area in patients with clinical symptoms or radiologic evidence suggesting extensive contamination. Complications of management can include duodenal fistulization, residual retroperitoneal or intrabdominal abscess, and ongoing sepsis. This report highlights the salient issues in the presentation, diagnosis, and modern management of patients with this rare complication of indwelling biliary stents

BACKGROUND: Duodenal diverticuli are present in up to 22% of the population. However, perforation of a duodenal diverticulum with spillage of enteric contents into the retroperitoneum is rare. METHODS: We report three cases of perforated duodenal diverticulitis. RESULTS: Clinical presentations varied widely from patients with acute abdominal findings and generalized sepsis to a patient with mild symptoms of abdominal discomfort. CT scanning was the imaging modality used to make an accurate diagnosis. Treatment approaches for the most stable patient included nonoperative management with antibiotics, bowel rest and parenteral alimentation, while the less stable patients underwent definitive surgery with complete diversion of gastric contents and biliary flow from the affected area of duodenum. CONCLUSIONS: This report highlights the salient issues in the presentation, diagnosis and modern management of patients with this potentially catastrophic disease

BACKGROUND: The number of US medical students applying for general surgery residency has been declining. Recent studies have shown that the issue of 'controllable lifestyle' has become a critical factor in medical students' decision-making process. We postulate that widespread implementation of resident work hour limitations would bolster medical students' interest in pursuing surgical careers. STUDY DESIGN: Students from New York University School of Medicine were surveyed about their attitudes toward work hour limitations and its effect on their interest in pursuing a surgical residency. One hundred thirty-two students participated. RESULTS: Nearly 95% of respondents believed that work hour limitations were a positive change and, if all other factors were equal, they would choose a training program that used work hour limitations over one that did not. The most common reasons cited in favor of limits were improvements in resident lifestyle (42%) and patient safety (34%). Fifty-three percent of respondents indicated that presence of work hour limitations alone would increase their interest in considering a surgical residency and only 2% of medical students indicated that it would lessen their interest in surgery. Not surprisingly, intellectual interest in a specialty was the most important factor in choosing a residency for 86% of students. Nevertheless, work hour limitations were designated a higher priority than future salary by 55% of medical students. CONCLUSIONS: The presence of work hour limitations has a positive impact on medical students' interest in surgery. Widespread implementation of work hour limitations may bolster the number of applications for surgical residency

We report three cases of abdominal wall necrotizing fasciitis that occurred as a result of leakage from displaced percutaneous endoscopic gastrostomy tubes. This is the first report of such a series. Patients underwent extensive operative excisions of their abdominal walls down to their posterior fascia. All patients tolerated their initial surgery, however, two patients ultimately expired from respiratory complications. The surviving patient underwent multiple repeat debridements and reconstructive abdominal wall surgery. We review the epidemiology of patients at risk for this complication and discuss its presentation, as well as the appropriate workup and management. We also address the issues of closure of large abdominal wall defects and future alimentation in this patient group. Finally, abdominal wall necrotizing faciitis from gastrostomy tube leakage is a devastating complication, and the development of preventative strategies for patients at risk is of paramount importance

BACKGROUND: There is an ongoing debate regarding the merits of resident work-hour limitations. We postulated that this issue would be a factor in the decision-making process of applicants to surgical residency. METHODS: Candidates for surgical residency at a university-based program completed an anonymous survey during their visit. Data was analyzed by analysis of variance and the chi-square test. RESULTS: Most candidates viewed work-hour limitations as being favorable to their future training. Nevertheless, work-hour limitations ultimately were not a critical factor in the decision-making process compared with issues such as quality of training and program reputation. Candidates ranked 'reading in surgery' the most likely way they would spend the leisure time afforded by work-hour limitations. CONCLUSIONS: Most applicants for surgical residency consider work hour-limitations as being favorable to their training and view the extra free time as an opportunity for furthering their education. However, other issues take precedence when choosing a residency

IL-12 gene transfer to hepatocytes using a recombinant adenovirus vector (AdIL-12) has been shown to protect against primary and metastatic liver tumors in mice. However, the mechanism of protection has been elusive and studies using depleting monoclonal antibodies or transgenic mice have purported it to be independent of T and NK cells. We postulated that depletion of NK cells may distort the experimental model and misrepresent the antitumor mechanism by altering the magnitude and duration of transgene expression. We show in mice treated with AdIL-12 that NK depletion increased serum IL-12 levels by more than 250-fold and prolonged transgene expression by nearly 2 weeks compared to nondepleted mice. To determine the contribution of NK cells to tumor protection after AdIL-12 treatment, we analyzed NK cells from treated animals. Isolated NK cells were markedly activated in terms of their lytic activity and IFN-gamma secretion. Adoptive transfer of NK cells from mice that had been treated with AdIL-12 to naive mice was sufficient to confer protection against colorectal hepatic metastases. This protection was mediated in part by NK-cell production of IFN-gamma. Our findings indicate that NK-cell depletion distorts the model of systemic AdIL-12 administration by markedly altering transgene expression, which then may potentiate other antitumor mechanisms, and that endogenous IL-12 overexpression activates NK cells, rendering them sufficient to protect against liver metastases. These data have critical implications for investigating the immunologic mechanisms of experimental models that utilize gene transfer

The unique immunological properties of the liver may be due to the function of hepatic dendritic cells (DC). However, liver DC have not been well characterized because of the difficulty in isolating adequate numbers of cells for analysis. Using immunomagnetic bead and flow cytometric cell sorting, we compared freshly isolated murine liver and spleen CD11c+ DC. We found that liver DC are less mature, capture less Ag, and induce less T cell stimulation than spleen DC. Nevertheless, liver DC were able to generate high levels of IL-12 in response to CpG stimulation. We identified four distinct subtypes of liver DC based on the widely used DC subset markers CD8alpha and CD11b. Lymphoid (CD8alpha+CD11b-) and myeloid (CD8alpha-CD11b+) liver DC activated T cells to a similar degree as did their splenic DC counterparts but comprised only 20% of all liver DC. In contrast, the two more prevalent liver DC subsets were only weakly immunostimulatory. Plasmacytoid DC (B220+) accounted for 19% of liver DC, but only 5% of spleen DC. Our findings support the widely held notion that liver DC are generally weak activators of immunity, although they are capable of producing inflammatory cytokines, and certain subtypes potently activate T cells