Cerebellar alterations in the weaver mouse

The fine structure of the cerebellum of weaver mouse was examined and the paucity of granule cells and their axons, the parallel fibers, was confirmed. Unexpectedly, however, the dendritic spines of the Purkinje cells which, in normal animals, are the postsynaptic mates of the parallel fibers, were present. Furthermore, their essential morphology and their staining reactions were indistinguishable from those of the Purkinje cell dendritic spines in normal animals. Possible mechanisms of development are discussed.

Malignant glioma of the brain-stem. A clinicopathological analysis of 13 cases

Thirteen cases of malignant glial tumours of the brain-stem that came to necropsy have been analysed in detail. These patients followed a rather uniform course defined by the early onset of signs and symptoms of increased intracranial pressure, poor response to radiotherapy, and short total duration of illness. Pathological features were also similar in all cases, with each tumour showing areas ranging from benign to frankly malignant. This regional variability points to the limited usefulness of small biopsies and also indicates the need for complete necropsy studies. The term `spongioblastoma polare' should probably be avoided, and it is suggested that the histological classification of glial brain-stem tumours be similar to the classification of such tumours elsewhere in the neuraxis.