Progressive changes in adherens junction structure during intestinal adenoma formation in Apc mutant mice.

The C57BL/6J-Min/+ (Min/+) mouse bears a mutant Apc gene and therefore is an important in vivo model of intestinal tumorigenesis. Min/+ mice develop adenomas that exhibit loss of the wild-type Apc allele (Apc(Min/-)). Previously, we found that histologically normal enterocytes bearing a truncated Apc protein (Apc(Min/+)) migrated more slowly in vivo than enterocytes with either wild-type Apc (Apc(+/+)) or with heterozygous loss of Apc protein (Apc(1638N)). To study this phenotype further, we determined the effect of the Apc(Min) mutation upon cell-cell adhesion by examining the components of the adherens junction (AJ). We observed a reduced association between E-cadherin and beta-catenin in Apc(Min/+) enterocytes. Subcellular fractionation of proteins from Apc(+/+), Apc(Min/+), and Apc(Min/-) intestinal tissues revealed a cytoplasmic localization of intact E-cadherin only in Apc(Min/+), suggesting E-cadherin internalization in these enterocytes. beta-Catenin tyrosine phosphorylation was also increased in Apc(Min/+) enterocytes, consistent with its dissociation from E-cadherin. Furthermore, Apc(Min/+) enterocytes showed a decreased association between beta-catenin and receptor protein-tyrosine phosphatase beta/zeta (RPTPbeta/zeta), and Apc(Min/-) cells demonstrated an association between beta-catenin and receptor protein-tyrosine phosphatase gamma. In contrast to the Apc(Min/+) enterocytes, Apc(Min/-) adenomas displayed increased expression and association of E-cadherin, beta-catenin, and alpha-catenin relative to Apc(+/+) controls. These data show that Apc plays a role in regulating adherens junction structure and function in the intestine. In addition, discovery of these effects in initiated but histologically normal tissue (Apc(Min/+)) defines a pre-adenoma stage of tumorigenesis in the intestinal mucosa.

Reciprocal expression of ERalpha and ERbeta is associated with estrogen-mediated modulation of intestinal tumorigenesis.

Menopausal hormone replacement therapy has been widely used to alleviate the symptoms of menopause and to decrease the detrimental effects of ovarian hormone loss on bone density and cardiovascular health. Multiple studies of colorectal cancer epidemiology also support a role for hormone replacement therapy in prevention of colorectal cancer. We studied the effect of ovariectomy and estrogen replacement on tumor formation in C57BL/6J-Min/+ (Min/+) mice, animals that bear a germline mutation in murine Apc. These mice develop multiple intestinal tumors that show loss of wild-type Apc protein. After ovariectomy, intestinal adenomas in Min/+ mice increased by 77% (P = 0.0004). Ovariectomized Min/+ mice that were treated with a replacement dose of 17beta-estradiol had the same number of tumors as Min/+ mice that were neither castrated nor treated with estrogen replacement (P = 0.85). Examination of estrogen receptor (ER) levels in intestinal tissue by immunoblot showed changes in relative expression levels of ERalpha and ERbeta, with highest ERalpha and lowest ERbeta expression in the normal-appearing intestine of Min/+ mice, and lowest ERalpha and highest ERbeta expression in the enterocytes of animals that received 17beta-estradiol. These results suggest that endogenous estrogens protect against Apc-associated tumor formation and that tumor prevention by 17beta-estradiol is associated with an increase in ERbeta and a decrease in ERalpha expression in the target tissue.

(+)-Catechin inhibits intestinal tumor formation and suppresses focal adhesion kinase activation in the min/+ mouse.

Colorectal cancer is sensitive to dietary influences. Epidemiological data linking high intake of fruits and vegetables to decreased cancer risk have prompted the search for specific plant constituents implicated in tumor prevention. This task is difficult because of the complex chemical composition of plant foods and the multifactorial nature of carcinogenesis. Researchers are aided in this effort by the C57BL/6J-Min/+ (Min/+) mouse, an animal bearing a germline defect in Apc that is similar to the initiating genetic event in the majority of human colorectal cancers. In this study, we treated Min/+ mice with (+)-catechin, a phenolic antioxidant abundant in certain fruits. Administration of (+)-catechin in an AIN-76A diet at doses of 0.1 and 1% decreased the intestinal tumor number by 75 and 71%, respectively. Mechanistic studies linked this effect to (+)-catechin-induced changes in integrin-mediated intestinal cell-survival signaling, including structural alteration of the actin cytoskeleton and decreased focal adhesion kinase (FAK) tyrosine phosphorylation. Immunoblot analysis of small intestine scrapings from Min/+ mice and Apc+/+ wild-type C57BL/6J littermates together with excised Min/+ adenomas showed increased expression of phosphorylated FAK in the macroscopically normal enterocytes of untreated Min/+ mice and adenomas. Confirming the relevance of this signaling pathway, treatment of Min/+ mice with (+)-catechin reduced the expression of phosphorylated FAK to a level similar to the wild-type littermate controls. Thus, the natural abundance and favorable bioavailability of (+)-catechin make it a promising addition to the list of potential colorectal cancer chemopreventive agents.

A prospective evaluation of the use of emergency department computed tomography for suspected acute appendicitis.

BACKGROUND: Computed tomography (CT) is used increasingly to evaluate suspected cases of acute appendicitis (AA) in the emergency department (ED). This prospective study was performed to test the hypothesis that the evaluation of AA by CT in the ED remains suboptimal and that erroneous interpretation diminishes its utility. METHODS: Consecutive patients 18 years of age or older were enrolled prospectively if AA was among the first three differential diagnoses listed in the record of patients undergoing evaluation of abdominal pain in the ED. Imaging of the abdomen and pelvis was obtained at the discretion of the ED staff or consultant surgeon. Initial CT interpretation was by a radiology resident or fellow along with the surgical staff, but final review by an attending radiologist occurred later. Age, gender, presenting symptoms, white blood cell (WBC) count, final CT results, and final pathology (for patients undergoing operation) were recorded. X +/- SEM, p < 0.05 by chi(2), ANOVA, or MANOVA was used for statistical analysis as appropriate. RESULTS: A CT scan was performed in 104 patients (83% of those meeting entry criteria), 35 of whom were male (mean age, 37 +/- 2 years) and 69 of whom were female (mean age, 39 +/- 3 years). Thirty-five patients had pathologically proved appendicitis, 28 of whom were diagnosed prospectively by CT. There were seven false-negative scans. Sensitivity, specificity, and positive predictive value for the initial CT reading were 80%, 91%, and 82%, respectively. Gender (p < 0.03), WBC count (p < 0.0002), and a positive initial CT reading (p < 0.0001) correlated with operative management. However, although final CT interpretation did correlate with pathologic confirmation of AA (p < 0.0001), initial CT interpretation did not correlate with the presence of AA (p = 0.52). CONCLUSION: The ability of CT to predict AA is dependent on the interpretative skill of the individual interpreting the images. Widespread use of CT in the evaluation of patients for AA should be implemented with caution until institution-specific protocols are validated.

The use of computed tomography for the diagnosis of acute appendicitis in children does not influence the overall rate of negative appendectomy or perforation.

BACKGROUND: Computed tomography (CT) has been used more frequently to diagnose acute appendicitis in children. The purpose of this study was to determine whether the use of CT has any influence on negative appendectomy or perforation rates. METHODS: Review of a prospective database of children having appendectomy for suspected acute appendicitis. Negative appendectomy and perforation rates were determined by correlation with final pathology reports. RESULTS: Eighty-five consecutive patients underwent appendectomy for the suspicion of acute appendicitis. The overall negative appendectomy rate was 17.6%, being 19.4% in females and 16.6% in males (p = 0.75). The overall accuracy, sensitivity and positive predictive value of CT were 75%, 91%, and 81%, respectively. Patients that had CT did not have a significantly lower rate of negative appendectomy (17.9% vs. 19.3%, p > 0.99) or perforation (26% vs. 17%; p = 0.53). CONCLUSIONS: The use of CT for the diagnosis of appendicitis in children does not change the negative appendectomy rate. Results of studies performed in adults may not be extrapolated to the evaluation of children with suspected acute appendicitis.

Interpretation of computed tomography does not correlate with laboratory or pathologic findings in surgically confirmed acute appendicitis.

BACKGROUND: Computed tomography (CT) is used increasingly to diagnose acute appendicitis, despite variable technique and interpretation. We hypothesized that CT interpretation would not reflect actual clinical-pathologic findings in all demographic patient groups. METHODS: A prospective university hospital database of 625 consecutive patients (1995-1999), all of whom were operated on for appendicitis (261, or 41.8%, within 24 hours of discretionary CT), was reviewed. CT and pathology data were obtained from final, written reports. CT criteria included free fluid or air, appendiceal visualization, mesenteric fat stranding, and blurred pericecal fat. Appendix pathology included acute, gangrenous, and perforated organs. Statistics were performed with the Fisher exact test (coordinate data) and univariate analysis of variance (continuous data); multivariate analysis of variance for independent effects on dependent variable (positive CT or pathology; P <.05). RESULTS: The mean age was 35 +/- 1 years with 46.6% being female patients. CT was done more often in women and after 1997 (both P <.05). The sensitivity and specificity of CT were 96.1% and 16.1%, respectively. The positive predictive value (PPV) and accuracy rate (A) were 90%, and 88%, respectively. After CT, the incidence of finding a normal appendix was lower (19.3% vs 12.3%, P <.05), especially if the white blood cell count (WBC) was normal (< or = 11K/microL, 6.1% vs 23.2%, P <.001). If the WBC was < or = 11K/microL with positive CT, PPV/A was 73. 7%/71.3%, whereas with WBC > 11K/microL and positive CT, PPV/A was 99.4%/93.3%. Multivariate analysis of variance showed that none of the individual variables used by the radiologist to determine a positive CT scan correlated with outcome determined by surgical pathology. A healthy appendix was predicted by a CT interpreted as negative and younger age (both P <.05), and especially by lower WBC (P <.0001), but not by gender or surgeon. CONCLUSIONS: Although the negative appendectomy rate was decreased by CT, there was no correlation between CT findings and pathologically proved disease. Other factors such as more precise patient selection by clinical criteria may also be improving outcome. A positive CT scan in a patient with a normal WBC should be interpreted with caution.

Secretory leukocyte protease inhibitor, an inhibitor of neutrophil activation, is elevated in serum in human sepsis and experimental endotoxemia.

OBJECTIVES: To document changes in serum secretory leukocyte protease inhibitor (SLPI) in human sepsis and in experimental endotoxemia in vivo. To compare changes in serum SLPI in human sepsis with changes in interleukin (IL)-6, IL-10, and tumor necrosis factor (TNF)-alpha. To determine whether or not changes in SLPI correlate with the severity of multiple organ dysfunction syndrome as measured by the maximal multiple organ dysfunction score. Finally, because neutrophils have been implicated in tissue injury associated with organ dysfunction, to determine whether recombinant human SLPI blocks activation of isolated human neutrophils. DESIGN: Case-control study and ex-vivo cellular assay. SETTING: Surgical intensive care unit and clinical research center of university hospitals; laboratory of a medical school. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: There was a significant dose-dependent elevation (50.2+/-4.0 ng/mL, p = .01) in plasma SLPI 12 hrs after administration of lipopolysaccharide to seven healthy adults (36.4+/-2.3 ng/mL). Further, serum concentrations of SLPI (132+/-15 ng/mL) were elevated in septic surgical patients compared with healthy controls (43+/-2 ng/mL, p < .01) and nonseptic surgical controls (69+/-10 ng/mL, p = .01). Serum SLPI concentrations correlated (r2 = .71, p < .01) better with organ dysfunction as measured by maximal multiple organ dysfunction score than did serum IL-6 (r2 = .49, p < .01), IL-10 (r2 = .05, p = .22), or TNF-alpha (r2 = .02, p = .44). We found that recombinant human SLPI in vitro inhibits TNF-alpha-induced hydrogen peroxide production by human neutrophils (ID50 = 1-2 microg/mL). CONCLUSIONS: Serum SLPI is elevated in human sepsis and experimental endotoxemia. Maximal concentrations of serum SLPI correlate significantly with maximal multiple organ dysfunction scores in patients with sepsis. Secretory leukocyte protease inhibitor may function to limit ongoing neutrophil-mediated tissue injury associated with organ dysfunction.

Colon cancer chemopreventive drugs modulate integrin-mediated signaling pathways.

Epidemiological studies of colorectal cancer incidence suggest that the development of this disease can be modulated by dietary factors. Among the micronutrients showing significant efficacy in tumor prevention are polyphenolic antioxidants found in fruits and vegetables. Epidemiological studies also indicate that nonsteroidal anti-inflammatory drugs (NSAIDs) decrease the incidence of colorectal cancer. Integrin-mediated cell-matrix contact provides critical signaling that regulates cellular proliferation, migration, and apoptosis. A signaling mediator for this system is focal adhesion kinase (FAK). Thus far, FAK has not been identified as a target for the inhibitory action of any chemopreventive drug in vivo or in vitro. However, the loss of integrin-mediated cell-matrix contact can induce apoptosis (anoikis), and effective chemopreventive agents typically increase the rate of enterocyte apoptosis. Therefore, we asked whether the NSAID, sulindac sulfide, and the phenolic antioxidant, caffeic acid phenethyl ester (CAPE), affected FAK expression or tyrosine phosphorylation in human colon carcinoma cells. We show that subapoptotic doses of both sulindac sulfide and CAPE caused a rearrangement of the actin cytoskeleton and consequently the loss of focal adhesion plaques. These drugs also reduced the tyrosine phosphorylation of FAK and an associated factor, p130Cas. Steady-state levels of these proteins, together with other relevant signaling molecules, remained unchanged after treatments. Finally, we show that both CAPE and sulindac reduced cell invasion, a functional assay for the inhibition of signaling downstream of FAK. These data strongly suggest that chemopreventive drugs can regulate FAK activity. In conclusion, these novel studies add modulation of integrin-mediated signaling to the spectrum of activity of NSAIDs and plant phenolics.

Choledochal cysts in adults: a report of two cases and review of the literature.

A choledocal cyst is a dilation of some component of the biliary tract that may include both intra- and extra-hepatic sites. They are classified into six types, all of which are relatively rare. Previously, choledochal cysts were treated with biliary-enteric bypass procedures. The current recommendation is to attempt complete excision to minimize the known risk of malignancy and the development of recurrent cholangitis or pancreatitis that may occur in patients with these cystic lesions. Two cases are discussed in which type I choledochal cysts presented. One was removed from a 31-yr-old man who presented with vague abdominal complaints the other from a 32-yr-old man who presented with pancreatitis. The epidemiology, diagnosis, surgical treatment, and risk of cancer in choledochal cysts is described.