Esbozo de una logica interna en la obra arquimediana

Presentado por B. L. van der Waerden     

Aktivität einiger Transaminasen in den mit SO2 behandelten Erbsen-Keimpflanzen

Summary Fifteen-day-old green pea seedlings were intoxicated 48 h by 1% gaseous sulphur dioxide and in their individual organs the activity of glutamate-oxalacetate (l-aspartate: 2-ketoglutarate-aminotransferase) and aspartate-pyruvate (l-alanine: oxalacetate-aminotransferase) transaminases estimated. The activity of glutamate-oxalacetate transaminase in the intoxicated seedlings was lowered in shoots by 77.8% and in roots by 78,9% as compared with the control plants. The activity of aspartate-pyruvate transaminase was lowered in shoots by 33.5%, in roots by 76% and in cotyledons by 54.5% in comparison with the control plants.     

Depression of experimental gastric ulcers and acute pancreatitis in rats treated by 5-azacytosine, 5-azacytidine and their N-methyl derivatives

5-Azacytosine, 1-methyl-5-azacytosine and 5-azacytidine administered to rats with a ligated pylorus block gastric secretion, gastric acidity, the extent of hemorrhage and the number and size of gastric defects. The same drugs also depress the development of experimental acute pancreatitis mediated in rats by interstitial administration of 7.5% natrium cholate into the pancreas in vivo. The drugs affected the amount of abdominal fluid and 6 h after the treatment the pathological changes were significantly decreased.     

Interaction of benznidazole reactive metabolites with nuclear and kinetoplastic DNA, proteins and lipids from Trypanosoma cruzi

Epimastigotes of Trypanosoma cruzi (Tulahuen strain Tul 0 stock) biotransform benznidazole (N-benzyl-2-nitro-1-imidazole acetamide) to reactive metabolites that bind covalently to DNA, proteins and lipids of the parasite. These effects might be related to the trypanocidal action of benznidazole, a chemotherapeutic agent against Chagas' disease.     

Galactose induced Balbiani-ring-like structures in chromosomes I and II ofChironomus thummi

Summary In one strain ofChironomus thummi, galactose feeding of the larvae induced the appearance of 2 Balbiani-ring-like structures on salivary gland chromosomes I and II. This phenomenon may be related to the galactose induction of BR6 inC. pallidivittatus.