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Biomedical subjects

F Scaravilli

Publications and source records attributed to F Scaravilli.

192 records · Page 11Linked to original sources
PubMedDate not supplied

Enzyme replacement in grafted nerve of twitcher mouse.

"Twitcher' is a recently recognized mouse mutant which, on the basis of morphological and enzymatic criteria, represents a murine model for globoid-cell leukodystrophy in man. In the twitcher mouse, myelin sheaths develop normally in peripheral nerves until about the fifteenth day when the rate of myelination declines, demyelination begins and Krabbe-type inclusions are seen in macrophages and Schwann cells. With age, demyelination becomes extensive, affecting fibres of all sizes. The axons are relatively spared, although they are smaller than normal. Twitcher peripheral nerves transplanted into normal hosts show, after 2 months, all the characteristics associated with globoid-cell leukodystrophy. After longer periods of time, however, pathological changes within the grafts appear considerably improved with only occasional evidence of myelin loss, little endoneurial oedema and few globoid cells. Migration of host Schwann cells into the graft can be excluded as a possible explanation. In the experiments reported here, we have attempted to determine whether the morphological improvement of grafted twitcher nerves is accompanied by an increase in activity of the enzyme galactosylceramidase. Our results show that galactosylceramidase activity in twitcher sciatic nerves grafted into normal hosts is variable after 1-2 months but indistinguishable from those in the host nerves and much higher than those in intact twitcher nerves after 4.5-9 months. In addition to migration of host Schwann cells, other tissues originating from the host can be excluded as cause of the high enzyme activity. This is the first evidence of long-term in vivo enzyme replacement, accompanied by improved pathology, in a genetic sphingolipidosis.

Animals↗
PubMedDate not supplied

Unusual development of polyoma virus in the brains of two patients with the acquired immune deficiency syndrome (AIDS).

Two HIV-positive male patients presented with a variety of symptoms including hemiparesis, unsteadiness, progressive loss of vision and poor memory. There were multiple non-enhancing lesions shown by CT scan in the white matter of the cerebral hemispheres. Specimens obtained by burr-hole biopsy showed the features of progressive multifocal leucoencephalopathy (PML) in both cases. Electron microscopy demonstrated round and rod shaped particles of papovavirus in the nuclei and cytoplasm of oligodendrocytes and in processes of astrocytes where abnormal and florid modes of viral replication were seen. Additional features observed were viral particles suggestive of an enterovirus in Case 1 and, in both specimens, massive membrane proliferation within both nuclei and cytoplasm of infected cells together with the presence of tubuloreticular structures (TRS) in the cytoplasm of endothelial cells. At post-mortem, the brain of patient 2 showed PML and HIV encephalitis. The presence of HIV was confirmed by immunohistochemical methods. We suggest that in AIDS patients the abnormality of the immune system induced by HIV causes abnormal replication patterns of papovavirus in the brain. In addition, these cases confirm the frequent occurrence in AIDS patients of TRS, now considered to be a marker for HIV.

Acquired Immunodeficiency Syndrome↗
PubMedDate not supplied

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL)--confirmation by cerebral biopsy in 2 cases.

CADASIL is a recently recognized familial form of subcortical multi-infarct dementia. The pathogenesis of the disease is unknown, but it is characterized pathologically by a novel vasculopathy affecting leptomeningeal and subcortical arteries. We describe 2 cases in which the diagnosis could be made from the cerebral biopsy appearances of affected leptomeningeal vessels. The ultrastructural appearances of the vessel wall deposit are illustrated, and their similarity to those of immune complex deposits discussed.

Biopsy↗