W. Thomas Smith

Medulloblastomas and other neural tumours in mice treated neonatally with N-ethyl-N-nitrosourea

SummaryNewborn mice of four inbred strains were injected with a single dose of N-ethyl-N-nitrosourea. The wide range of tumours induced included a small number in the central and peripheral nervous systems. The 4 brain tumours all arose in the cerebellum. Three in one strain were medulloblastomas showing continuity with the internal granular layer. All three tumours showed diffuse infiltration through the molecular layer and continuity with densely-packed islets of cells that marginated immediately beneath the pia and closely resembled remnants of a persistent fetal external granular layer. The medulloblastomas are discussed with special relevance to the histogenesis of the equivalent tumour in man.

Vitamin B12 deficiency in captive monkeys and its effect on the nervous system and the blood

Monkeys fed vegetarian diets develop neurological and haematological abnormalities; paralysis can occur though the neural lesions (cerebral degeneration, posterior and lateral column degeneration of the spinal cord, segmental and wallerian degeneration of the peripheral nerves) are usually not evident during life. It is clearly important that the diet given to captive animals should contain an adequate amount of vitamin B12, and that newly captive monkeys should not be used for research purposes unless shown to have normal serum levels of the vitamin.

Peripheral neuropathy in ageing rats fed clioquinol and a maize diet

SummaryRats fed clioquinol and a maize diet developed much more severe neuropathy in old age than did rats fed only a maize diet. The findings suggest that, in the rat, clioquinol can accentuate other known causes of neuropathy.