RESUMEN
NG-nitro-D-arginine (D-NNA) produced pressor responses in rats by acting via chiral inversion intoNG-nitro-L-arginine (L-NNA), an inhibitor of nitro oxide synthase. The present investigation aimed to study the roleof the D-amino acid oxidase (DAAO) in chiral inversion of D-NNA and the relationship between DAAO activitieson various D-amino acids and their inversion rate. Benzoate (400 mg/kg) or creatinine (400 mg/kg), two inhibitorsof DAAO, blocked D-NNA-induced pressor responses in rats. Furthermore, the addition of the pure DAAOsignificantly potentiates L-NNA production rate in kidney homogenates by approximately 2-folds. The in vivo andin vitro results suggested that DAAO plays an essential role in the pressor responses elicited by D-NNA.Moreover, crude DAAO solution from the kidney showed marked selection (the maximal ratio of Kcat/Km wasnearly 15 times) on different D-amino acids that exhibited similar chiral inversion rate in vivo, suggesting that otherenzymes, such as transaminase, are also required for the entire process of D-NNA chiral inversion.
RESUMEN
Objective: To investigate the immunological mechanism of influenza A virus for murine S180 ascites sarcoma. Methods: After inoculation with S180 sarcoma cells, mice were i. p. injected with influenza A virus or vehicle 15 days. The average living time and survival rate of the mice were examined. The levels of IL-2, IL-6 and TNF-? were detected. The sarcoma cell's apoptosis was detected by DNA ladder, flow cytometry (FMC) , fluorescent microscope and e-lectron microscope (EM). Results: The average living time and survival rate of the mice injected with Influenza A virus were significantly longer or higher than that of the controls. The levels of IL-2, IL-6 and TNF-? also had the same differences. The apoptosis cells were detected by EM and fluorescent microscope. Sub-diploid peaks were observed by FCM a-nalysis and DNA ladder was seen after electrophoresis in the ascites cells. Conclusion: Our results demonstrated that the feasibility and potential of delivery of influenza A virus as a general means for the treatment of S180 ascites sarcoma.