Role of Helicobacter pylori [H.pylori] infection and cyclooxygenase-2 [COX-2] expression in chronic gastritis and gastric carcinoma: an immunohistochemical study

Malignant tumors of the stomach are common, but the incidence of stomach cancer varies from country to another, probably as a result of genetic, epigenetic and environmental factors. Stomach cancer often occurs in older people whose stomachs produce only small quantities of acid. Although infection with Helicobacter pylori has been proven beyond doubt in the aetiopathogenesis of various gastric disorders, not much is known about the role of H.pylori infection in onset and progression of chronic gastritis as well as gastric cancer. Although recent studies have indicated that the clinicopathological parameters in patients with gastric carcinoma, the prognosis of advanced cancer still remains unsatisfactory. This study aimed at investigating the expression of H pylori antibody and cyclooxygenase-2 [COX-2] in cases with chronic gastritis and gastric carcinomas and to correlate this expression with various clinicopathological parameters. Paraffin sections from previously diagnosed chronic gastritis [CG] and gastric carcinomas [GC] were classified, graded and staged according to the updated for CG and the World Health Organization [WHO], for GC. Two sections were immunohistochemically stained for antibodies against H.pylori and COX-2. One section was stained with Feulgen stain for assessment of ploidy and proliferative activity using the Image analyzer system CAS 200. Infection with H.pylori and cox-2 overex-pression are common in patients with chronic gastritis and gastric carcinoma. Both anti-H pylori and cox-2 proteins are implicated in gastric carcinogenesis and their over expression may be a good predicator for worse prognosis and poor patient's outcome

High performance liquid chromatographic determination of cox-2 inhibitor rofecoxib in human plasma.

A convenient, sensitive and simple method for the determination of rofecoxib in human plasma is presented. The analytical technique is based on reversed phase high performance liquid chromatography coupled with UV detector (Knauer, Germany) set at 272 nm. The retention time of rofecoxib after recovery from plasma, was 8.9 minutes. The method has been validated over a linear range of 50-450 ng/ml from plasma. After validation the method was used to study the pharmacokinetic profile of rofecoxib in 6 healthy volunteers as per DCGI guidelines after administration of a single oral dose (50 mg). The extraction efficiency from plasma varied from 93.95-99.58%. The minimum quantifiable concentration was set at 50 ng/ml (% CV < 10%). The pharmacokinetic parameters were Cmax = 318.58 +/- 30.65 ng/ml at tmax = 2.66 +/- 0.25 hours, AUC0-t = 4007.88 +/- 438.32 ng hour/ml, AUC0-yen = 5454.66 +/- 822.29 ng hour/ml, Kel = 0.0433 +/- 0.0067/hour, and t1/2 = 16.36 +/- 2.89 hours.