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K Ota

Publications and source records attributed to K Ota.

981 records · Page 55Linked to original sources
PubMedDate not supplied

Antitumor activity and toxicity in mice of RA-700, a cyclic hexapeptide.

The antitumor activity of RA-700, a cyclic hexapeptide isolated from Rubia Cordifolia, was evaluated in comparison with deoxy-bouvardin and vincristine (VCR). As regards the proliferation of L1210 cultured cells, the cytotoxicity of RA-700 was similar to that of VCR but superior to that of deoxy-bouvardin. The IC50 value of RA-700 was 0.05 mcg/ml under our experimental conditions. RA-700 inhibited the incorporation of 14C-leucine at a concentration at which no effects were observed on the incorporation of 3H-thymidine and 3H-uridine in L1210 culture cells in vitro. The antitumor activity of RA-700 was similar to that of deoxy-bouvardin and VCR against P388 leukemia. Daily treatment with RA-700 at an optimal dose resulted in 118% ILS. As with deoxy-bouvardin and VCR, the therapeutic efficacy of RA-700 depends on the time schedule. RA-700 showed marginal activity against L1210 leukemia (50% ILS), similar to that of deoxy-bouvardin but inferior to that of VCR. RA-700 inhibited Lewis tumor growth in the early stage after tumor implantation, whereas deoxy-bouvardin and VCR did not. As regards toxicity, a slight reduction of peripheral WBC counts was observed with the drug, but no reduction of RBC and platelet counts. BUN, creatinine, GPT and GOT levels in plasma did not change with the administration of the drug.

Animals↗
PubMedDate not supplied

Efficacy of three live vaccines against highly virulent infectious bursal disease virus in chickens with or without maternal antibodies.

Since 1990, highly virulent infectious bursal disease virus (IBDV), which induces high mortality, has been infecting even vaccinated flocks in Japan. We report the efficacy of three live vaccines that are available in Japan. Two mildly attenuated strains (A and B) and one intermediate strain (C) were each tested both in specific-pathogen-free (SPF) chickens and in commercial chickens that have maternal antibodies against IBDV. Chickens were vaccinated at 20 days old and challenged with highly virulent IBDV 10 days post-vaccination. Protection was determined 7 days after challenge by measuring bursa/body weight ratios, histopathological lesions, and antibody responses to IBDV. All three lie vaccines conferred protection to SPF chickens. However, only vaccine C protected 100% of vaccinated commercial chickens against highly virulent IBDV; Vaccines A and B respectively protected three-fourths and none of vaccinated commercial chickens from severe bursal lesions. Vaccines A, B, and C and highly virulent IBDV induced bursal lesions in 3%, 0%, 23%, and 61% of inoculated commercial chickens, respectively. These results suggest that serological determination of the optimum vaccination time for each flock is required to effectively control highly virulent IBDV in the field. The optimum vaccination timing could be approximated by titrating the maternal IBDV antibodies of 1-day-old chicks by an enzyme-linked immunosorbent assay or by an agar gel precipitin test.

Animals↗
PubMedDate not supplied

Pharmacokinetics of platinum in cancer patients following intravenous infusion of cis-diammine(glycolato)platinum, 254-S.

The pharmacokinetics of platinum in cancer patients were examined following an intravenous infusion of cis-diammine(glycolato) platinum, 254-S. The plasma concentrations of total platinum, which decreased biexponentially after the infusion, were proportional to the dose over the range of 10 to 120 mg/m2, suggesting linearity of the pharmacokinetics. The plasma concentrations of ultrafilterable platinum were similar to those of total platinum and there was little difference in the pharmacokinetic parameters between total platinum and ultrafilterable platinum. These findings show that almost all of the platinum derivative is unbound, which is thought to be the active form, in plasma after administration of 254-S. Platinum was eliminated from blood faster when given as 254-S rather than as cisplatin because of the low protein binding. The urinary recovery within 24 hours was about half of the dose, suggesting that platinum given as 254-S was distributed to various tissues and organs in an active form.

Adolescent↗