NEUROPATHOLOGICAL EFFECTS OF DOSING DOGS WITH ISONICOTINIC HYDRAZIDE AND WITH ITS METHANOSULPHONATE DERIVATIVE

Focal spongy changes in the central nervous system of sheep and cattle

A focal form of vacuolation in the white matter of the thalamus of 13 sheep and 2 cattle is described. The individual vacuoles were similar in appearance to those reported in other forms of spongy degeneration, but they were differentiated by their consistent neuroanatomical localization in the thalamic radiation of all 15 animals. Thirteen of these were sheep used in toxicity experiments and 11 had shown signs of convulsive activity.

Hereditary neuraxial edema in Hereford calves

Twelve newborn Hereford calves from 8 herds showed extensor spasms upon stimulation and inability to rise. Neuraxial lesions consisted of widespread vacuolation interpreted as edema and seen chiefly in terminal portions of myelinated bundles and in gray substance containing heavily myelinated fibers. Genetic analysis of 2 of these herds indicated an autosomal recessive pattern of transmission tracing back to a single bull. The identity of the disease in all herds suggested that it had the same hereditary basis in all of them.