Deficient Pms2, ERCC1, Ku86, CcOI in field defects during progression to colon cancer.

In carcinogenesis, the "field defect" is recognized clinically because of the high propensity of survivors of certain cancers to develop other malignancies of the same tissue type, often in a nearby location. Such field defects have been indicated in colon cancer. The molecular abnormalities that are responsible for a field defect in the colon should be detectable at high frequency in the histologically normal tissue surrounding a colonic adenocarcinoma or surrounding an adenoma with advanced neoplasia (well on the way to a colon cancer), but at low frequency in the colonic mucosa from patients without colonic neoplasia. Using immunohistochemistry, entire crypts within 10 cm on each side of colonic adenocarcinomas or advanced colonic neoplasias were found to be frequently reduced or absent in expression for two DNA repair proteins, Pms2 and/or ERCC1. Pms2 is a dual role protein, active in DNA mismatch repair as well as needed in apoptosis of cells with excess DNA damage. ERCC1 is active in DNA nucleotide excision repair. The reduced or absent expression of both ERCC1 and Pms2 would create cells with both increased ability to survive (apoptosis resistance) and increased level of mutability. The reduced or absent expression of both ERCC1 and Pms2 is likely an early step in progression to colon cancer. DNA repair gene Ku86 (active in DNA non-homologous end joining) and Cytochrome c Oxidase Subunit I (involved in apoptosis) had each been reported to be decreased in expression in mucosal areas close to colon cancers. However, immunohistochemical evaluation of their levels of expression showed only low to modest frequencies of crypts to be deficient in their expression in a field defect surrounding colon cancer or surrounding advanced colonic neoplasia. We show, here, our method of evaluation of crypts for expression of ERCC1, Pms2, Ku86 and CcOI. We show that frequency of entire crypts deficient for Pms2 and ERCC1 is often as great as 70% to 95% in 20 cm long areas surrounding a colonic neoplasia, while frequency of crypts deficient in Ku86 has a median value of 2% and frequency of crypts deficient in CcOI has a median value of 16% in these areas. The entire colon is 150 cm long (about 5 feet) and has about 10 million crypts in its mucosal layer. The defect in Pms2 and ERCC1 surrounding a colon cancer thus may include 1 million crypts. It is from a defective crypt that colon cancer arises.

Pathogenesis of portal hypertensive gastropathy: translating basic research into clinical practice.

Portal hypertensive gastropathy (PHG) is often seen in patients with portal hypertension, and can lead to transfusion-dependent anemia as well as acute, life-threatening bleeding episodes. This Review focuses on the mechanisms that underlie the pathogenesis of PHG that provide reasonable grounds for the treatment of this condition, and ultimately enable translation of basic research into clinical practice. Increased portal pressure associated with cirrhosis and liver dysfunction is critical for the development of clinically significant PHG, and leads to impaired gastric mucosal defense mechanisms that render the stomach susceptible to mucosal injury. The use of pharmacological agents such as beta-blockers reduces the frequency of bleeding episodes in PHG. As a last resort, surgical decompression of the portal system, transjugular intrahepatic stent placement and liver transplantation can resolve this condition. Elimination of known risk factors for gastric injury such as alcohol, aspirin and traditional NSAIDs is critical. The role of Helicobacter pylori colonization of the gastric mucosa in PHG is not clear. Careful and critical interpretation of human and experimental data can be helpful to establish a rationale for the medical management of this important condition.

Isolated right segmental hepatic duct injury following laparoscopic cholecystectomy.

PURPOSE: Laparoscopic cholecystectomy (LC) is the treatment of choice for gallstones. There is an increased incidence of bile duct injuries in LC compared with the open technique. Isolated right segmental hepatic duct injury (IRSHDI) represents a challenge not only for management but also for diagnosis. We present our experience in the management of IRSHDI, with long-term follow-up after treatment by a multidisciplinary approach. METHODS: Twelve consecutive patients (9 women, mean age 48 years) were identified as having IRSHDI. Patients' demographics, clinical presentation, management and outcome were collected for analysis. The mean follow-up was 44 months (range 2-90 months). RESULTS: Three patients had the LC immediately converted to open surgery without repair of the biliary injury before referral. Treatments before referral included endoscopic retrograde cholangiopancreatography (ERCP), percutaneous drainage and surgery, isolated or in combination. The median interval from LC to referral was 32 days. Eleven patients presented with biliary leak and biloma, one with obstruction of an isolated right hepatic segment. Post-referral management of the biliary lesion used a combination of ERCP stenting, percutaneous drainage and stent placement and surgery. In 6 of 12 patients ERCP was the first procedure, and in only one case was IRSHDI identified. In 6 patients, percutaneous transhepatic cholangiography (PTC) was performed first and an isolated right hepatic segment was demonstrated in all. The final treatment modality was endoscopic management and/or percutaneous drainage and stenting in 6 patients, and surgery in 6. The mean follow-up was 44 months. No mortality or significant morbidity was observed. CONCLUSION: Successful management of IRSHDI after LC requires adequate identification of the lesion, and multidisciplinary treatment is necessary. Half of the patients can be treated successfully by nonsurgical procedures.

Post-sphincterotomy bleeding after the introduction of microprocessor-controlled electrosurgery: does the new technology make the difference?

BACKGROUND: Bleeding as a complication of endoscopic sphincterotomy is influenced by several factors. The objective of this study was to compare rates of bleeding after sphincterotomy performed with two different electrosurgical current generators (Valleylab SSE2L and ERBE ICC200). METHODS: A total of 6179 consecutive reports of ERCP were analyzed to compare the frequency of endoscopically and clinically evident bleeding after sphincterotomy when using the Valleylab SSE2L generator (from February 1994 to November 1997) and the ERBE ICC200 generator (from December 1997 to September 2000). Relevant risk factors were assessed by univariate analysis and significant predictors were included in a multiple logistic regression model. RESULTS: A total of 2711 sphincterotomies were performed in 2309 patients (1749 biliary, 962 pancreatic). Endoscopically observed bleeding occurred in 68 patients (5.5%) in the ValleyLab group and 13 (1.2%) in the ERBE group. The ValleyLab generator was independently associated with an increase in endoscopically observed bleeding (OR 4.02: 95% CI[2.13, 7.61], p <0.001). There was no significant difference in clinically evident bleeding between the two groups. CONCLUSIONS: Use of the microprocessor-controlled ERBE electrosurgical generator for endoscopic sphincterotomy was associated with a significantly lower frequency of endoscopically observed bleeding but not clinically evident bleeding.

Mucosal repair and COX-2 inhibition.

The healing of gastric ulcer is a complicated process that involves the proliferation of epithelial and endothelial cells and the concerted actions of a wide range of growth factors. Prostaglandins play an important role in ulcer healing. Expression of cyclooxygenase-2 (COX-2) is markedly upregulated around the margins of gastric ulcers and its inhibition leads to a delay of ulcer healing. Several of the growth factors that promote ulcer healing may work in part through COX-2-dependent mechanisms. Angiogenesis, which is crucial to ulcer healing, is tightly regulated by growth factors. Treatment with selective COX-2 inhibitors appears to alter the balance of serum levels of growth factors, favoring an inhibition of angiogenesis. Given the importance of COX-2 in regulating ulcer healing, caution should be taken in the use of selective inhibitors of COX-2 by patients at risk of ulcer disease.