Cheyer

The open environment of the eye is continuously subject to an influx of foreign agents that can activate complement. Decay-accelerating factor (DAF), membrane cofactor protein (MCP) and CD59 are regulators that protect self-cells from autologous complement activation on their surfaces. They are expressed in the eye at unusually high levels but their physiological importance in this site is unstudied. In the rat, a structural analogue termed 5I2 antigen (5I2 Ag) has actions overlapping DAF and MCP. In this investigation, we injected F(ab')2 fragments of 5I2 mAb into the conjunctiva and aqueous humor, in the latter case with and without concomitant blockage of CD59...

PURPOSE: Cell surface complement regulatory proteins have been identified in high levels in ocular tissues, but no experimental model is available for examining their physiological roles. To develop such a model, the distribution of 5I2 antigen, a protein possessing the functions of the human decay-accelerating factor (DAF [CD55]) and membrane cofactor protein (MCP [CD46]), and rat inhibitory protein (CD59), the homologue of the human membrane inhibitor of reactive lysis (MIRL[CD59]) were characterized in the rat eye and ocular adnexal structures...

BACKGROUND: A mutation in c-K-ras (KRAS2) has long been implicated as one of the important early events in the development of a large proportion of human colon cancers. Aberrant crypt foci, putative preneoplastic lesions identified microscopically in wholemounts of colons, have been shown to occur with high frequency in the colons of animals treated with colon carcinogens and in the grossly normal mucosas of patients with colon cancer. PURPOSE: In this study, we asked whether the mutational activation of K-ras occurs in the aberrant crypt foci of human colon...

Increased proliferative activity has been described frequently in the colons of animals treated with colon carcinogens and of patients at increased risk of colon cancer; it has been proposed as an intermediate biomarker of colon cancer. Aberrant crypt foci, microscopic lesions identified in whole-mount preparations of colons, are thought to be putative pre-neoplastic lesions. The present studies were carried out to evaluate the proliferative activity of aberrant crypt foci at several different time periods, and of tumors after a single dose of azoxymethane (AOM) in F344 rats...