Iwao Hirono

Induction of a cerebellar disorder with cycasin in newborn mice and hamsters.

Summary A single administration of cycasin, β-d-glucosyloxyazoxymethane, was given in dosage near the LD50 level to newborn mice and hamsters within 24 hr after birth. Under these conditions cycasin produced a distinctive neurologic disorder. In the affected newborns there was rapid and extensive necrosis of the cells of the external granular layer (embryonal layer) of the cerebellum. In animals surviving to maturity this resulted in defective development of the molecular and granule cell layers. The affected animals had ataxia and gait disturbances. Comparable administration of cycasin to rats within 24 hr after birth produced no apparent disorder of the central nervous system.

Carcinogenicity examination of betel nuts and piper betel leaves

A dry powder of betel nuts, piper betel leaves and lime was administered to rats. Epidermal thickening was frequently observed in the upper digestive tracts of rats in groups fed the betel nut diet mixed with lime and the betel leaves diet, and a forestomach papilloma was seen in 1 rat given betel leaves diet. These epidermal changes were scarcely seen in rats given either betel nut or normal diet alone.

INDUCTION OF A RETINAL DISORDER WITH CYCASIN IN NEWBORN MICE AND RATS

The newborns, less than 24 hours old, of C57BL/kg/day) was studied in rats which were kept either on a standard laboratory diet, or on a diet containing a large amount of fat (40%) and cholesterol (5%). PDC significantly increased the lactate dehydrogenase activity in the aortae of rats kept on a standard diet, and the malate dehydrogenase activity in the aortae of rats kept on high‐fat diet.6 strain mice and Morlyamaso strain rats received a single subcutaneous Injection of cycasin (0.5 mg/kg/day) was studied in rats which were kept either on a standard laboratory diet, or on a diet containing a large amount of fat (40%) and cholesterol (5%). PDC significantly increased the lactate dehydrogenase activity in the aortae of rats kept on a standard diet, and the malate dehydrogenase activity in the aortae of rats kept on high‐fat diet.g body weight In mice, 0.2 mg and 0.5 mg/g body weight In rats), and effects of cycasin on the retina were studied. Rosette formations were seen after the necrosis of cells in the neuroblasts layer. Especially, In rats treated with a large dose of cycasin, retinal hemorrhage from the choroid completely arrested the differentiation to each layer in the retina and resulted In its severe disorder. These changes were considered to belong to the same category as necrotic damage in the external granular layer of the cerebellum induced by cycasin.