Azauridine in viral eye infections

Azapyrimidine nucleosides: metabolism and inhibitory mechanisms

Triazine nucleosides represent highly active compounds affecting different cellular processes. While 6-azauridine displays a rather selective inhibitory effect, biological action of 5-azacytidine reflects the polyvalent inhibitory mechanism of the drug (interaction with pyrimidine synthesis de novo, incorporation into RNA and DNA, depressed maturation of ribosomal RNA, inhibition of RNA and DNA methylation, etc.) and the analog displays pronounced cytostatic and immunosuppressive activity. 5-Aza-2'-deoxycytidine action is directed against DNA synthesis similar to that of 5-azacytosine arabinoside. N4-Substituted derivatives of 5-azacytidine affect gastric secretion and together with 5-azacytosine and 5-azacytidine represent a new type of drugs with antiulcer activity. 6-Amino-5-azacytosine nucleosides interfere with the metabolism of purines rather than pyrimidines as evidenced by the character of their inhibitory mechanism and measurement of conformation. 6-Azauridine (as 2',3',5'-triacetate) and 5-azacytidine were used with certain success in human chemotherapy, the first one as a drug affecting recalcitrant psoriasis, the second one for the treatment of different forms of leukemia. The inhibitory mechanisms of individual azapyrimidine nucleosides are discussed in relation to their known biological effects.

Herpes simplex virus skin infection in hairless mice: treatment with antiviral compounds

A hairless mouse-herpes simplex virus skin infection experimental model was used to evaluate the efficacy of the antiviral compounds 9-beta-d-arabinofuranosyladenine (ara-A), 5-iodo-2'-deoxyuridine (IUdR), and 6-azauridine (aza-U). Ara-A and IUdR, when administered intraperitoneally by several different dosage schedules, reduced the severity of cutaneous herpetic lesions and the incidence of paralysis and increased significantly the number of survivors. A more rapid healing of the lesions and an increase in the mean survival time also was observed. A delay of 24 to 48 h in the initiation of treatment after the infection was more effective than treatments started at the time of inoculation. Treatment with ara-A was somewhat superior to that with IUdR, but aza-U was totally ineffective. Enhancement of the evolution of the infection was noted after treatment with aza-U.