Lisa R. Dixon

Detection of endogenous biomolecules in Barrett's esophagus by Fourier transform infrared spectroscopy

Fourier transform infrared (FTIR) spectroscopy provides a unique molecular fingerprint of tissue from endogenous sources of light absorption; however, specific molecular components of the overall FTIR signature of precancer have not been characterized. In attenuated total reflectance mode, infrared light penetrates only a few microns of the tissue surface, and the influence of water on the spectra can be minimized, allowing for the analyses of the molecular composition of tissues. Here, spectra were collected from 98 excised specimens of the distal esophagus, including 38 squamous, 38 intestinal metaplasia (Barretts), and 22 gastric, obtained endoscopically from 32 patients. We show that DNA, protein, glycogen, and glycoprotein comprise the principal sources of infrared absorption in the 950- to 1,800-cm−1 regime. The concentrations of these biomolecules can be quantified by using a partial least-squares fit and used to classify disease states with high sensitivity, specificity, and accuracy. Moreover, use of FTIR to detect premalignant (dysplastic) mucosa results in a sensitivity, specificity, positive predictive value, and total accuracy of 92%, 80%, 92%, and 89%, respectively, and leads to a better interobserver agreement between two gastrointestinal pathologists for dysplasia (κ = 0.72) versus histology alone (κ = 0.52). Here, we demonstrate that the concentration of specific biomolecules can be determined from the FTIR spectra collected in attenuated total reflectance mode and can be used for predicting the underlying histopathology, which will contribute to the early detection and rapid staging of many diseases.

Early histologic changes in fibrosing cholestatic hepatitis C

Recurrent hepatitis C (RHCV) after liver transplantation is almost universal, and occasional patients will have an aggressive course characterized histologically by pericellular/sinusoidal fibrosis and cholestasis, known as fibrosing cholestatic hepatitis (FCH). The early stages and evolution of this disease have not been well characterized. A total of 77 liver biopsies performed for indication (nonprotocol) were evaluated for necroinflammation, rejection, cholestasis, and fibrosis. Control groups were composed of protocol biopsies from HCV transplant patients (10 biopsies) as well as non–HCV transplant patients (6 biopsies). Scoring for necroinflammation, rejection, and fibrosis were compiled using standard criteria (hepatic activity index, Banff, Ishak, METAVIR). Pericellular fibrosis was staged with a novel “sinusoidal” system. A cholestasis scoring system was developed to quantitate parenchymal and portal features of cholestasis. Biopsies were categorized as rejection, RHCV, FCH, and stable based on histology and clinical information. FCH was found to have a higher fibrosis stage overall when compared to most diagnostic groups, regardless of the staging system used. Additionally, sinusoidal fibrosis was significantly higher in the FCH diagnosis group. Cholestasis was more prominent in biopsies of FCH in all comparisons. In conclusion, the presence of cholestasis and fibrosis with mild to moderate RHCV should raise the suspicion of FCH. When studying the evolution of these cases, the first abnormality to appear is RHCV and cholestasis, fibrosis develops soon after, and both continue to worsen until the point of allograft failure or patient death. Liver Transpl, 2006.

Using an immune functional assay to differentiate acute cellular rejection from recurrent hepatitis C in liver transplant patients.

In transplant recipients transplanted for hepatitis C, presentation of abnormal transaminases can herald the presentation of recurrent hepatitis C, cellular rejection, or both. Given the sometimes ambiguous histology with these 2 entities, the ability to distinguish them is of great importance because misinterpretation can potentially affect graft survival. We used an immune functional assay to help assess the etiology of abnormal liver function test results in liver transplant recipients. Blood samples for the immune functional assay were taken from 42 recipients prospectively at various times post‐transplant and compared with clinical and histologic findings. In patients whose liver biopsy showed evidence of cellular rejection, the immune response was noted to be very high, whereas in those with active recurrence of hepatitis C, the immune response was found to be very low. This finding was found to be statistically significant (P < 0.0001). In those patients in whom there was no predominant histologic features suggesting 1 entity over the other, the immune response was higher than in those with aggressive hepatitis C but lower than in those with cellular rejection. In conclusion, these data show the potential utility of the ImmuKnow assay as a means of distinguishing hepatitis C from cellular rejection and its potential usefulness as a marker for outlining the progression of hepatitis C. Liver Transpl 15:216–222, 2009.

Randomized, controlled trial of standard, large-capacity versus jumbo biopsy forceps for polypectomy of small, sessile, colorectal polyps

BACKGROUND Polypectomy with cold biopsy forceps is a frequently used technique for removal of small, sessile, colorectal polyps. Jumbo forceps may lead to more effective polypectomy because of the larger size of the forceps cup. OBJECTIVE To evaluate the efficiency of cold jumbo biopsy forceps compared with standard forceps for polypectomy of small, sessile, colorectal polyps. DESIGN Randomized, controlled trial. SETTING Outpatient endoscopy center. PATIENTS This study involved 140 patients found to have at least one eligible polyp defined as a sessile polyp measuring ≤6 mm. INTERVENTION Polypectomy with cold biopsy forceps. MAIN OUTCOME MEASUREMENTS Complete visual polyp eradication with one forceps bite. RESULTS In 140 patients, a total of 305 eligible polyps were detected (151 removed with jumbo forceps and 154 with standard forceps). Complete visual eradication of the polyp with one forceps bite was achieved in 78.8% of the jumbo forceps group and 50.7% of the standard forceps group (P < .0001). Biopsies from the polypectomy sites of adenomatous polyps thought to be visually completely eradicated with one bite showed a trend toward a higher complete histologic eradication rate with the jumbo forceps (82.4%) compared with the standard forceps (77.4%), but the difference did not reach statistical significance (P = .62). The withdrawal time for visual inspection of the colon and time to perform polypectomies were significantly shorter in the jumbo forceps group (mean 21.43 vs 18.23 minutes; P = .02). LIMITATIONS Lack of blinding to the type of forceps used. CONCLUSION The jumbo biopsy forceps is superior to the standard forceps in removing small, sessile polyps. ( CLINICAL TRIAL REGISTRATION NUMBER NCT00855790.).

Contemporary Results with Ampullectomy for 29 "Benign" Neoplasms of the Ampulla

BACKGROUND Ampullectomy may be an appropriate oncologic procedure in selected patients. Sparse data exist on procedure-related complications and the relationship between histologic analysis and outcomes. STUDY DESIGN We retrospectively reviewed our experience with ampullectomy in 29 patients with a preoperative benign histologic diagnosis over 15 years (1991 to 2006). Presenting signs, symptoms, and preoperative diagnostic studies were reviewed. Postoperative complications and followup for recurrence were recorded. The abilities of preoperative histologic biopsy, intraoperative frozen section, and final histologic analysis to guide management and predict outcomes were determined. RESULTS Median age was 63 years. Jaundice was present in 30% of patients. Median length of hospital stay was 9 days. Forty-five percent of patients had a complication, and there was one postoperative mortality (3%). Ampullary adenomatous neoplasms were present in 89% of patients. Preoperative biopsy had complete concordance with final pathology in 76% of patients. Preoperative biopsy and intraoperative frozen section failed to identify carcinoma in four patients. Pancreaticoduodenectomy was performed within 7 days in the postoperative period in three of these patients. After ampullectomy (median followup=16 months), recurrences were identified in two patients (8%) with benign tumors. No patients with high-grade dysplasia (n=4) have had recurrence. CONCLUSIONS Preoperative biopsy and intraoperative frozen section analysis have limitations in the management of patients undergoing ampullectomy. High-grade dysplasia on preoperative biopsy is not an absolute contraindication to ampullectomy. Morbidity of ampullectomy is significant, but longterm outcomes of this procedure, in patients without invasive malignancy, are acceptable.

Autoimmune Esophagitis: IgG4-related Tumors of the Esophagus

We present a case of a 23-year-old gentleman who presented with dysphagia, weight loss, and recurrent esophageal strictures requiring multiple dilatations. An endoscopic ultrasound with esophagogastroduodenoscopy revealed a mass present in the distal esophagus. Fine needle aspiration suggested that the mass in the lower esophagus resembled a gastrointestinal stromal tumor. After surgical resection, final pathologic analysis revealed that the tumor was comprised of benign-appearing fibroinflammatory cells with an increase and predominance of IgG4-positive plasma cells. The microscopic appearance was consistent with a benign condition as a result of an IgG4-related process. He did not, however, have any other symptoms indicative of systemic autoimmune disease or connective tissue disorders. We present the pre-operative imaging, operative management, pathologic diagnosis, and literature review of this rare condition and the first known report of autoimmune esophagitis as part of the IgG4 spectrum of diseases.

Autoimmune Pancreatitis and Concurrent Small Lymphocytic Lymphoma: Not Just a Coincidence?

CaseA 76-year-old gentleman presented with painless jaundice, weight loss, and anorexia. Computed tomography imaging revealed fullness of the pancreatic head and multiple enlarged retroperitoneal lymph nodes. Cholangiogram revealed a distal common bile duct stricture. Due to concerns of malignancy, the patient underwent operative exploration. Several enlarged lymph nodes in the aortocaval region and a firm hard mass in the pancreatic head were found. Frozen section from one of the lymph nodes was suspicious for low-grade lymphoma. A pancreaticoduodenectomy was performed. Histologic analysis of the pancreatic head revealed a lymphoplasmacytic infiltrate with stromal fibrosis consistent with autoimmune pancreatitis. The retroperitoneal lymph nodes were involved by small lymphocytic lymphoma.DiscussionAutoimmune pancreatitis is the most common benign diagnosis after pancreatic resection for presumed malignancy. It has a well-documented association with autoimmune conditions, such as Sjögren’s syndrome, inflammatory bowel disease, and sclerosing cholangitis. Additionally, chronic lymphocytic leukemia–small lymphocytic lymphoma is often associated with autoimmune phenomena, most notably autoimmune hemolytic anemia. However, an association between autoimmune pancreatitis and small lymphocytic lymphoma has not been previously described. To our knowledge, this is the first reported case of a patient with concurrent autoimmune pancreatitis and small lymphocytic lymphoma.

Pancreatic adenocarcinoma patients with localised chronic severe pancreatitis show an increased number of single beta cells, without alterations in fractional insulin area

Aims/hypothesisRecent histological analysis of pancreases obtained from patients with long-standing type 1 diabetes identified chronic islet inflammation and limited evidence suggestive of beta cell replication. Studies in rodent models also suggest that beta cell replication can be induced by certain inflammatory cytokines and by gastrin. We therefore tested the hypothesis that beta cell replication is observed in non-autoimmune human pancreatic disorders in which localised inflammation or elevated gastrin levels are present.MethodsResected operative pancreatic specimens were obtained from patients diagnosed with primary adenocarcinoma (with or without chronic severe pancreatitis) or gastrinoma. Additional pancreatic tissue was obtained from autopsy control patients. Immunohistochemistry was used to assess fractional insulin area, beta cell number and replication rate and differentiation factors relevant to beta cell development.ResultsFractional insulin area was similar among groups. Patients with pancreatic adenocarcinoma and localised chronic severe pancreatitis displayed significant increases in the number of single beta cells, as well as increased beta cell replication rate and levels of neurogenic differentiation 1 in islets. Patients with gastrinoma demonstrated significant increases in the number of single beta cells, but the beta cell replication rate and islet differentiation factor levels were similar to those in the control group.Conclusions/interpretationThese findings indicate that chronic severe pancreatic inflammation can be associated with significant effects on beta cell number or replication rate, depending on the distribution of the cells. This information may prove useful for attempts seeking to design therapies aimed at inducing beta cell replication as a means of reversing diabetes.

Identification of adeno-associated viral vectors suitable for intestinal gene delivery and modulation of experimental colitis.

Effective gene transfer with sustained gene expression is an important adjunct to the study of intestinal inflammation and future therapy in inflammatory bowel disease. Recombinant adeno-associated virus (AAV) vectors are ideal for gene transfer and long-term transgene expression. The purpose of our study was to identify optimal AAV pseudotypes for transduction of the epithelium in the small intestine and colon, which could be used for studies in experimental colitis. The tropism and transduction efficiencies of AAV pseudotypes 1-10 were examined in murine small intestine and colon 8 wk after administration by real-time PCR and immunohistochemistry. The clinical and histopathological effects of IL-10-mediated intestinal transduction delivered by AAVrh10 were examined in the murine IL-10⁻/⁻ enterocolitis model. Serum IL-10 levels and IL-10 expression were followed by ELISA and real-time PCR, respectively. AAV pseudotypes 4, 7, 8, 9, and 10 demonstrated optimal intestinal transduction. Transgene expression was sustained 8 wk after administration and was frequently observed in enteroendocrine cells. Long-term IL-10 gene expression and serum IL-10 levels were observed following AAV transduction in an IL-10-/- model of enterocolitis. Animals treated with AAVrh10-IL-10 had lower disease activity index scores, higher colon weight-to-length ratios, and lower microscopic inflammation scores. This study identifies novel AAV pseudotypes with small intestine and colon tropism and sustained transgene expression capable of modulating mucosal inflammation in a murine model of enterocolitis.

Development of Professionalism in Graduate Medical Education: A Case-Based Educational Approach From the College of American Pathologists’ Graduate Medical Education Committee

Professionalism and physician well-being are important topics in academic medicine. Lapses in professional judgment may lead to disciplinary action and put patient’s health at risk. Within medical education, students and trainees are exposed to professionalism in the institution’s formal curriculum and hidden curriculum. Development of professionalism starts early in medical school. Trainees entering graduate medical education already have developed professional behavior. As a learned behavior, development of professional behavior is modifiable. In addition to role modeling by faculty, other modalities are needed. Use of case vignettes based on real-life issues encountered in trainee and faculty behavior can serve as a basis for continued development of professionalism in trainees. Based on the experience of program directors and pathology educators, case vignettes were developed in the domains of service, research, and education and subdivided into the areas of duty, integrity, and respect. General and specific questions pertaining to each case were generated to reinforce model behavior and overcome professionalism issues encountered in the hidden curriculum. To address physician burnout, cases were generated to provide trainees with the skills to deal with burnout and promote well-being.