G. M. ZuRhein

Brain tissue from seven patients with progressive multifocal leukoencephalopathy was tested for the presence of papovaviruses. JC virus, ahuman papovavirus, was identified in all seven cases. Virus was isolated in tissue culture from extracts from each of four patients and was detected by immunofluorescence in sections from the other three. The new osolates were indistinguishable from the prototypical JC strain serologically and in all biological characteristics examined. Thus JC virus has, to date, been associated with 20 cases of progressive multifocal leukoencephalopathy.

Clinical, histological, chemical and enzymatic studies are reported in five patients in two families with juvenile GM 1 gangliosidosis (GM 1 gangliosidosis, Type 2). The clinical picture includes onset of mental and motor retardation beginning at about one year of age and progressive neurological decline with death usually within the first decade. Bony deformities, although mild, are often present and are diagnostically helpful. Ganglioside GM 1 and a galactose‐containing polysaccharide (similar to keratan sulfate) are stored, β‐galactosidase activities are reduced in tissues and cultured skin fibroblasts; both homozygotes and heterozygotes can be detected by this method. The differentiation of juvenile GM 1 gangliosidosis from generalized gangliosidosis (GM 1 gangliosidosis, Type 1) is discussed.

A 35-year-old woman with metastatic breast cancer experienced acute monocular visual loss. Her fundus examination was normal. The patient died 48 h later, and autopsy demonstrated hematogenously disseminated aspergillosis. The retrobulbar optic nerve of the affected eye showed infarction due to massive embolization with Aspergillus fumigatus. Although the retrobulbar optic nerve is relatively resistant to ischemia, its meningeal derived blood supply may be occluded by massive showers of emboli.