The role of Helicobacter pylori infection in gastric cancer was evaluated in a high-risk population in Venezuela using serological assays in a study of 302 cases and 483 neighborhood controls. To investigate the claim that assays for H. pylori should use antigens derived from local strains, four different assays derived from Venezuelan and European strains were used. Prevalence of IgG H. pylori...

It has been shown by the work presented in this paper that it is possible to dephosphorylate enzymically pepsin and pepsinogen with a variety of phosphatases. With the aid of a phosphodiesterase and the prostate phosphatase it has been established that the phosphorus in the two proteins is present as a diester and connects two sites of the peptide chain in a cyclic configuration. Removal of the...

Potentiometric titrations of pepsinogen as functions of ionic strength and temperature were studied. It was found that the ionic strength has a minor effect on the titration behavior of the protein. The maximum values of the buffering capacity in the pH range of 6.0 to 9.0 were found at pH values corresponding to those at which a conformational change of the protein occurs as determined by opti...

Conventional in vitro studies of pepsinogen secretion have measured secretion into the bulk medium and have demonstrated the critical role of Ca2+ in the process. The present study was undertaken to obtain further details of the process of secretion and its relation to Ca2+changes over very short time periods. The relation between Ca2+ mobilization and exocytosis in an isolated individual pepti...

A study of the kinetics of the transformation of swine pepsinogen into pepsin under a variety of conditions has been made. The results show that the transformation as a whole is essentially autocatalytic in nature under all conditions. Evidence is presented to show the existence of a compound intermediate between pepsinogen and pepsin. This compound was found to be a reversibly dissociable comp...

alcium just got a promotion. Findings by Caroppo et al. (page 111) reveal that in addition to its many roles inside the cell, Ca 2 ϩ has a distinct extracellular purpose: it acts via a Ca 2 ϩ receptor (CaR) to regulate the function of gastric epithelial cells. It has been known for some time that extracellular Ca 2 ϩ can be sensed by the CaR. The team noted that a Ca 2 ϩ gradient was generated ...

Evidence relating to the structure and properties of swine pepsinogen and pepsin has been reviewed and used to suggest a tentative two dimensional picture of the skeleton of these two proteins. When pepsinogen, a folded single peptide chain, is converted to pepsin, there is a profound change in the physical and chemical properties of the protein. In an as yet unknown manner, except that it is i...

gastric cancer is the most common gi cancer. it has a very high incidence rate in the northeastern iran.contrary to western countries and japan, the incidence of gastric cancer has been increasing in iran during the past two decades. helicobacter pylori infection is the most important risk factor for developing gastric cancer. however, the presence and influence of other environmental and genet...