Sequence-dependence of cisplatin and 5-fluorouracil in advanced and recurrent gastric cancer.

This randomized controlled clinical trial was designed to compare the safety and effectiveness of different sequences of treatment with cisplatin (CDDP) and 5-fluorouracil (5-FU) in patients with unresectable advanced and post-operative recurrent gastric cancer. Patients with unresectable advanced or post-operative recurrent gastric cancer were randomly assigned by a registration center to group A or B. Group A received CDDP (80 mg/m(2)) as a continuous 2-h intravenous infusion on day 1 and 5-FU (700 mg/m(2)) as a continuous intravenous infusion on days 2-5. Group B was given 5-FU (700 mg/m(2)) as a continuous intravenous infusion on days 1-4, followed by CDDP (80 mg/m(2)) as a continuous 2-h intravenous infusion on day 5. Each course of chemotherapy was repeated every 28 days. A total of 74 patients were enrolled. One patient died accidentally, and 5 could not be evaluated. Response was assessable in 68 patients. The response rate was 31.3% (10/32) in group A as compared with 13.9% (5/36) in group B. Although the response rate was higher in Group A, the difference was not significant (p=0.085). The response rate in patients with diffuse type tumors was significantly lower in group B. There was no difference between the groups in response among patients with intestinal type tumors. The median overall survival was 239 and 174 days and time to progression was 175 and 140 days in group A and group B, respectively. Although there were trends toward longer survival and time to progression in group A, the differences between the groups were not statistically significant. There was also no difference in the type or incidence of adverse reactions. The results of this controlled study indicate that the overall response rate was slightly but not significantly higher in patients who received CDDP before 5-FU. Among patients with diffuse type tumors, the response rate was significantly lower when 5-FU was administered before CDDP. Our results suggest that CDDP should be given before 5-FU in patients with gastric cancer when treated with a combination of CDDP and 5-FU.

Human prorenin has "gate and handle" regions for its non-proteolytic activation.

We investigated the mechanism for non-proteolytic activation of human prorenin using five kinds of antibodies. Each of the antigens, L1PPTDTTTFKRI11P, T7PFKRIFLKRMP17P, I11PFLKRMPSIRESLKER26P, M16PPSIRESLKER26P, and G27PVDMARLGPEWSQPM41P, was designed from the tertiary structure of predicted prorenin. These antibodies were labeled anti-01/06, anti-07/10, anti-11/26, anti-16/26, and anti-27/41, respectively, for their binding specificities. Inactive recombinant human prorenin (0.1 nM) bound to various concentrations of anti-01/06, anti-11/26, and anti-27/41 antibodies at 4 degrees C with equilibrium dissociation constants of 138, 41, and 22 nM, respectively. However, intact prorenin (0.1 nM) did not show significant binding to 200 nM anti-07/10 and anti-16/26 antibodies for 20 h. Ninety percent of prorenin (0.1 nM) was found to be non-proteolytically activated by incubation with anti-11/26 antibodies (200 nM) at 4 degrees C for 20 h. Prorenin was not active even under complex with either anti-01/06 or anti-27/41 antibodies. Prorenin was also reversibly activated at pH 3.3 and 4 degrees C for 25 h. The acid-activated prorenin bound to anti-07/10 and anti-16/26 antibodies as well as to anti-01/06, anti-11/15, and anti-27/41 antibodies at neutral pH and 4 degrees C in 2 h. Their dissociation constants were 13, 40, 8.6, 3.6, and 14 nM, respectively. The acid-activated prorenin was re-inactivated by incubation at pH 7.4 and 4 degrees C in 50 h. Anti-07/10 and anti-11/26 antibodies inhibited such re-inactivation at 25 degrees C by more than 90% and 50%, respectively, whereas other kinds of antibodies did not prevent the re-inactivation at 25 degrees C. These results indicate that prorenin has "gate" (T7PFKR10P) and "handle" (I11PFLKR15P) regions critical for its non-proteolytic activation.