The quantities of total and free guanine, adenine, hypoxanthine, and six of their methylated derivatives and of 6-succinoaminopurine have been measured in urine speci mens from cases of hepatocellular carcinoma and cirrhosis of the liver, and from normal subjects. Total base was defined as the sum of the free purine plus the increment released by means of acid hydrolysis. Analyses were per form...

A series of tritylated and dimethoxytritylated analogues of selected pyrimidine and purine nucleosides were synthesized and evaluated for their in vitro inhibitory activity against two important members of the genus Flavivirus in the Flaviviridae family, the yellow fever (YFV) and dengue viruses (DENV). Among all compounds tested, the 5'-O-tritylated and the 5'-O-dimethoxytritylated 5-fluorouri...

The quantities of total and free guanine, adenine, hypoxanthine, and six of their methylated derivatives and of 6-succinoaminopurine have been measured in urine speci mens from cases of hepatocellular carcinoma and cirrhosis of the liver, and from normal subjects. Total base was defined as the sum of the free purine plus the increment released by means of acid hydrolysis. Analyses were per form...

Several purine analogues are reported to show a teratogenic action in mammalian embryos when ad ministered at calculated dosage [reviewed by Giroud and Tuchmann-Duplessis-(1), Cahen (2) and Nishimura (3, 4); Kury et al. (5)]. We established that some methylated xanthines such as theophylline, theobromine and caffeine induce skeletal defects and subcutaneous hematoma in mice (6). Hypoxanthine al...

The structural effects of chemical modifications upon the affinity of purine nucleosides to cytidine-transport system in Bacillus subtilis were investigated using a series of modified derivatives. The interaction involves protein molecule(s) which require the presence and proper orientation of the sugar residue and its hydroxylic functions. Moreover, a specific interaction with the heterocyclic...