Background & Aims Clostridium difficile (C.difficile) is the leading cause of nosocomial infectious diarrhea. Increasing incidence, antibiotic resistance and more virulent strains have dramatically increased the number of C.difficile-related deaths worldwide. The innate host response mechanisms to C.difficile are not resolved; however, we hypothesize that hypoxia-inducible factor (HIF-1) plays an innate protective role in C.difficile colitis. Thus, we assessed the impact of C.difficile toxins on the regulation of HIF-1 and evaluated the role of HIF-1α in C.difficile-mediated injury/inflammation. Methods In vitro studies assessed HIF-1α mRNA, protein levels and DNA binding events in human mucosal biopsies and Caco-2 cells exposed to C.difficile toxins. In vivo studies employed the murine ileal loop model of C.difficile toxin-induced intestinal injury. Mice with targeted deletion of HIF-1α in the intestinal epithelium were used to assess the impact of HIF-1α signaling in response to C.difficile toxin. Results Mucosal biopsies and Caco-2 cells exposed to C.difficile toxin displayed a significant increase in HIF-1α transcription and protein levels. Toxin-induced DNA binding was also observed in Caco-2 cells. Toxin-induced HIF-1α accumulation was attenuated by nitric oxide synthase inhibitors. In vivo, deletion of intestinal epithelial HIF-1α resulted in more severe toxin-induced intestinal injury and inflammation. In contrast, stabilization of HIF-1α, with dimethyloxallyl glycine, attenuated toxin-induced injury and inflammation. This was associated with an induction of HIF-1-regulated protective factors including VEGFa, CD73 and intestinal trefoil factor and down-regulation of proinflammatory molecules TNF and KC. Conclusions Our study is the first to describe the innate protective role for HIF-1α in response to C.difficile toxins. Harnessing the innate protective actions of HIF-1α in response to C.difficile toxins may represent a novel form of therapy for C.difficile-associated disease.

Inflammatory bowel disease (IBD) is associated with intestinal smooth muscle dysfunction. Many smooth muscle contractile events are associated with alterations in Ca 2ϩ -sensitizing pathways. The aim of the present study was to assess the effect of colitis on Ca 2ϩ sensitization and the signaling pathways responsible for contractile dysfunction in murine experimental colitis. Colitis was induced in BALB/c mice by providing 5% dextran sulfate sodium (DSS) in drinking water for 7 days. Contractile responses of colonic circular smooth muscle strips to 118 mM K ϩ and carbachol (CCh) were assessed. DSS induced a T H 2 colitis [increased interleukin (IL)-4 and IL-6] with no changes in T H 1 cytokines. Animals exposed to DSS had increased CCh-induced contraction (3.5-fold) and CCh-induced Ca 2ϩ -sensitization (2.2-fold) responses in intact and ␣-toxin permeabilized colonic smooth muscle, respectively. The contributions of extracellular signal-regulated kinase (ERK) and p38 mitogen-activated protein kinase (MAPK) to CCh-induced contractions were significantly increased during colitis. Ca 2ϩ -independent contraction induced by microcystin was potentiated (1.5-fold) in mice with colitis. ERK and p38MAPK (but not Rho-associated kinase) contributed to this potentiation. ERK1/2 and p38MAPK expression were increased in the muscularis propria of colonic tissue from both DSS-treated mice and patients with IBD (ulcerative colitis Ͼ Ͼ Crohn's disease). Murine T H 2 colitis resulted in colonic smooth muscle hypercontractility with increased Ca 2ϩ sensitization. Both ERK and p38MAPK pathways contributed to this contractile dysfunction, and expression of these molecules was altered in patients with IBD.It has been hypothesized that an imbalance of the T H 1/T H 2 immune response plays a central role in the pathogenesis of inflammatory bowel disease (IBD) (Neurath et al., 2002;Xavier and Podolsky, 2007). The mediators of intestinal inflammation are also known to impair gastrointestinal motility in human disease and animal models, which may be a reflection of altered smooth muscle function. Alterations in gastrointestinal motility with resultant changes in transit contribute to the abdominal pain, intestinal cramping, and diarrhea characteristically associated with IBD. Furthermore, defects in smooth muscle function can lead to the development of toxic megacolon. While it is commonly accepted that smooth muscle contractility is altered in inflamed intestine, there is still considerable disagreement whether intestinal contractility is increased or decreased in IBD. T H 1 and T H 2 immune responses play different roles in dysfunction of smooth muscle contractility. Tumor necrosis factor

Conventionally prepared endobiliary brushings are moderately (42%) sensitive and highly (98%) specific in detecting malignancy. The performance and morphological features of brushings prepared by Thinprep, a liquid-based method are mostly unknown. All brushings were retrieved from the laboratory files. Disease was classified as benign or malignant by linkage with the provincial cancer registry and sensitivity, specificity, positive (PPV) and negative predictive values (NPV) calculated. True positives and negatives were reviewed and predictive morphological features analysed by regression tree analysis. Out of 149 brushings, 55 (37%) were positive and 94 (63%) negative. Malignancy was identified in 86 (58%) and benign disease in 63 (42%) of the cases. The sensitivity was 51%, specificity 83%, PPV 80% and NPV 55%. Absolute discriminants of positive and negative brushings were not found, but nuclear cytoplasmic ratio was a useful feature. The performance of Thinprep-prepared brushings from this anatomical site was comparable with conventional preparations.

Acquired diverticular disease of the vermiform appendix is a rare condition that usually presents with the symptoms of acute appendicitis. This analysis was undertaken to determine the spectrum and prevalence of the associated lesions in acquired appendiceal diverticulosis. Thirty-one cases of acquired appendiceal diverticular disease were identified from files over a period of 15 years (1982)(1983)(1984)(1985)(1986)(1987)(1988)(1989)(1990)(1991)(1992)(1993)(1994)(1995)(1996). Diverticulosis was the only abnormality in 17 cases (54.8%). An associated neoplastic epithelium was present in nine (29%) patients (seven adenomata and two goblet cell carcinoids), fecalith formation in three (9.7%), and a neuroma in two (6.5%). Although rare, diverticular disease of the vermiform appendix was frequently seen in association with an adenomatous mucosa. In our experience, one appendiceal adenoma coexisted with a colonic adenocarcinoma. In conclusion, the diagnosis of appendiceal diverticulosis necessitates the exclusion of coexisting appendiceal neoplasia. Int J Surg Pathol 6(1): [23][24][25][26][27][28] 1998

In contrast to the common tumors of the prostate, seminal vesicle demonstrates low potential for neoplastic proliferation. Of the rare primary seminal vesicle tumors, adenocarcinoma is the most common, but there are also rare seminal vesicle neoplasms which demonstrate epithelial and stromal components. These neoplasms have been described in the literature under various names, including "epithelial-stromal tumor," "cystic epithelial-stromal tumor," "cystadenoma," "cystomyoma," "mesenchymoma," "Müllerian adenosarcoma-like tumor," "phyllodes tumor," and "cystosarcoma phyllodes." The spectrum of reported mixed epithelial-stromal tumors (MEST) of seminal vesicle encompasses low, intermediate and high-grade tumors, but the precise distinction and nomenclature for these tumors remain unsettled. We propose a common nomenclature for these tumors, based on the review of published cases and 2 index cases from our practice, which represent the low-grade category. The first patient was 46 years old and presented with seminal vesicle neoplasm detected on routine rectal examination. The neoplasm measured 4 cm in greatest dimension, and completely replaced the left seminal vesicle. The tumor was circumscribed and consisted of multiple cysts separated by spindle-cell stroma. The second patient was a 60-year-old man, who had an incidental seminal vesicle neoplasm, which was discovered when he underwent a radical prostatectomy for a prostatic adenocarcinoma, (Gleason score 3+4, stage 3a). Both neoplasms contained hypercellular stroma, which was composed of uniform spindle cells, arranged in fascicles and interspersed between the glands. Both tumors lacked worrisome morphology, such as infiltrative borders, cell atypia, increased mitotic activity, hemorrhage, and necrosis. The stromal cells were reactive for estrogen and progesterone receptors, and desmin. The cysts and dilated glands were lined by epithelial cells, which were positive for cytokeratin 7 and were negative for prostate-specific antigen and prostate-specific acid phosphatase. The first patient underwent prostatectomy and was alive and without evidence of disease recurrence or progression after 11 years of follow-up. Similarly, the second patient had no evidence of disease recurrence or progression after 8 months of follow-up. We propose that term seminal vesicle "mixed epithelial-stromal tumor" be used to designate the tumors of the seminal vesicle containing epithelial and stromal components, with a distinction of grade based on the histologic features and the biological behavior. Histologic features to be evaluated for grade separation include stromal atypia, mitotic activity, nuclear pleomorphism, and tumor necrosis. Designations "low-grade MEST," "intermediate-grade MEST (uncertain malignant potential)," and "high-grade MEST" of seminal vesicle can be applied to these tumors to better characterize and study them in the future.