C5b-8 Step Lysis of Swine Endothelial Cells by Human Complement and Functional Feature of Transfected CD59

The authors established several swine endothelial cell (SEC) lines expressing human CD59 by transfection of cDNA, and assessed the function of the transfectant molecules in comparison with those of membrane cofactor protein (MCP) and decay-accelerating factor (DAF) in an in vitro hyperacute rejection model of swine to human discordant xenograft. At the usual expression rate, DAF and MCP protected SEC from human complement mediated cell lysis, but CD59 did not block human complement attack on SEC. However, CD59 protects SEC from cell lysis when sufficiently expressed as in human umbilical vein (HUVEC). The authors examined why CD59 needed so many molecules to protect human complement-mediated SEC lysis and found that SEC underwent lysis by human C5b-8. The degree of C5b-8 step lysis of SEC was approximately 70% of the total activity (C5b-9). Additionally, CD59 protected human complement activation less efficiently at the C5b-8 step than at the C9-step. Therefore, to overcome human complement mediated SEC lysis, C8 activity must be inhibited by dense expression of CD59.     

Multiple biopsies of normal‐looking urothelium in patients with superficial bladder cancer: Are they necessary?

BACKGROUND: The objective of the study presented here was to assess the usefulness and indications of multiple biopsies of normal-appearing urothelium in patients with superficial bladder cancer. METHODS: Between December 1996 and December 2002, multiple biopsies of normal-appearing bladder mucosa were performed in 100 patients with superficial bladder transitional cell carcinoma. Biopsy specimens were taken from seven different sites in females and nine different sites in males. RESULTS: In eight of 100 patients, bladder cancers were detected in the biopsy specimens. Three cases were Ta and five were Tis. All of the five patients with carcinoma in situ (CIS) in their biopsy specimens had multiple papillary broad-base tumors and positive urinary cytology. The detection ratio of CIS in patients with these findings was 17.9% (5/28). No concomitant CIS was detected in the 72 patients who had a solitary tumor, pedunculated tumor(s), or negative urinary cytology. CONCLUSION: Multiple mucosal biopsies of normal-appearing urothelium are not necessary for all patients with superficial bladder cancer. They are, however, necessary for patients with multiple papillary broad-base tumors and positive urinary cytology.