Biomedical subjects

F Scaravilli

Publications and source records attributed to F Scaravilli.

At least 163 records · Page 9Linked to original sources

PubMed1986

The peripheral neuropathy in Machado-Joseph disease.

Peripheral nerve biopsies were taken from 11 patients with Machado-Joseph disease (MJD), a heredo-degenerative disease within the group of autosomal dominant ataxias. On the basis of the clinical symptoms, 2 patients were found to suffer from type I, 4 from type II and 5 from type III. All cases shared the same pathological features, which consisted of a reduction in density of myelinated and unmyelinated fibres and an increase in endoneurial collagen. It was also observed that some Schwann cells were not related to axons, whilst others showed numerous budding processes. The intensity of the changes varied considerably: it was mild in type I and II and severe in type III. Peripheral nerve changes in MJD are compared with those previously described in other forms of heredo-ataxias. It is concluded that involvement of peripheral nerves is a significant feature in this group of diseases and that peripheral nerve biopsy could be useful in the identification of the subtypes of MJD.

Adult↗

PubMed1986

X-irradiation impairs regeneration of peripheral nerve across a gap.

The effects of X-irradiation on the regeneration of peripheral nerve across a gap were studied in the mouse. The right sciatic nerve was transected and 3 days later a 20-Gy dose of X-rays was administered to the hind limb, which was shielded so that the irradiation affected either the proximal, the distal or both parts of the nerve. Within a few hours of irradiation, the proximal and distal nerve stumps were inserted into a polythene tube within which they were separated by a 5-mm gap. After 1 or 2 months the sciatic nerves were processed for examination by light and electron microscopy. Irradiation affected axonal growth, differentiation of Schwann cells and formation of a perineurium. These effects were most marked when both the proximal and distal stumps had been exposed to X-rays. At 2 months there were fewer axons in the irradiated than in control nerves (P less than 0.01), but all of the larger axons which had regenerated were myelinated, albeit more thinly than in the controls. The changes in the pattern of regeneration in the irradiated nerves are interpreted as being largely due to radiation damage to Schwann cells.

Animals↗

PubMed1986

The abnormal development of the gracile nucleus in the neurological mutant rat mf.

A morphological and quantitative study was carried out of the prenatal and early postnatal development of the gracile nucleus in the mutant rat 'mutilated foot' (mf), which is affected by a sensory neuropathy inherited by autosomal recessive transmission. Microscopic examination showed that the nucleus of both normal and mf rats become morphologically identifiable at embryonic day 19 and that its appearance was comparable in the two groups of rats up to postnatal day 2. Subsequently the nucleus in the mutants appeared smaller than in control rats and the number of nerve cells in it decreased dramatically. Glomeruli, the type of synapses known to be formed between primary sensory ascending fibres and dendrites of gracile nerve cells, were observed in the mf rat, but were greatly reduced in number and in size compared with those in normal littermates. Reconstruction of nerve cell volumes showed that, in mf rats, volumes increased considerably less than in controls. These results suggest that the abnormalities observed in the gracile nucleus of mf rats are secondary to the decreased number of afferent fibres originating from the dorsal root ganglia and represent a form of 'anterograde transneuronal degeneration'. In the mutant this is particularly severe and occurs at a rapid pace since it takes place in immature organisms, known to be particularly vulnerable to this type of lesions.

Afferent Pathways↗

PubMed1986

The development and pathogenesis of the sensory neuropathy in the mutant rat mf.

A study was made of the development of sensory pathways in the mutant rat mutilated foot (mf) which is affected by a sensory neuropathy with autosomal recessive inheritance. Microscopic abnormalities are well recognizable at the fifteenth embryonic day. By day 16, dorsal root ganglia are smaller than normal and show more numerous foci of cell necrosis which continue throughout the remainder of gestation and during the first and second postnatal days. During this period the number of ganglion cells decreases sharply. Reconstruction of cell volumes shows that the larger cells are more severely affected. The secondary sensory nuclei (gracile nuclei) are normal at birth but during the first two postnatal weeks become progressively smaller than in normal rats. The results suggest that the mutant gene acts primarily on the dorsal root ganglia causing excessive neuronal cell death. Qualitatively, the events in this mutant are closely similar to 'programmed cell death' in the normal. It is likely that neurons of second order nuclei, which are not contacted by afferent fibres, undergo a process of transneuronal degeneration as a secondary effect of excessive ganglion cell loss.

Animals↗

PubMed1985

Primary intracranial histiocytic lymphoma with Langerhans' granules. A light microscopic and ultrastructural study.

An intracranial tumor classified as a histiocytic lymphoma was studied with light and electron microscopic examination and immunocytochemical methods. The characteristics of the malignant mononuclear phagocyte cells are described. The presence of some cells containing Langerhans' granules suggests differentiation towards a specialized cell of the mononuclear phagocyte system: the Langerhans' cell.

Adult↗

PubMed1985

Secondary transneuronal degeneration: cortical changes induced by peripheral nerve section in neonatal rats.

Secondary transneuronal degeneration of the cortico-spinal tract (CST) has been induced after sciatic nerve section in newborn rats. Observations made 21-60 days after the lesion showed a considerable decrease in number of myelinated and unmyelinated fibres of the CST ipsilateral to the lesion and of horseradish peroxidase-labelled nerve cells in the somato-sensorimotor cortex of the contralateral cerebral hemisphere. This phenomenon which has never been observed in spite of the frequent studies of experimental peripheral nerve lesions, may be significant in normal and pathological development.

Animals↗

PubMed1985

Intracerebral neuroblastoma. Report of a case with neuronal maturation and long survival.

A case of primary intracerebral neuroblastoma with long survival is reported. The initial biopsy at the age of 3 years showed a primitive, poorly differentiated tumour. Nine years later, the recurrent tumour examined by light and electron microscopy had the appearances of a cerebral neuroblastoma with many mature neurons and occasional abnormal astrocytic elements.

Brain Neoplasms↗

PubMed1985

Encephalomyeloneuropathy in the absence of a detectable neoplasm. Clinical and postmortem findings in three cases.

The clinical and postmortem findings in three cases of encephalomyeloneuropathy are reported. Two patients presented with subacute sensory neuropathy and one with amnesia and confusion. In none of these cases was a tumour detected clinically or at autopsy. Neuropathological examination showed inflammatory lesions in the brain, spinal cord and posterior root ganglia indistinguishable from encephalomyeloneuropathy occurring as a remote effect of carcinoma.

Aged↗

PubMed1985

Rhino-orbital zygomycosis.

A 63-year-old diabetic man presented with sinusitis with orbital and intracranial signs progressing over one week, due to zygomycosis. Despite control of the diabetes, surgical excision of infected tissue and antifungal therapy he died in the fifth week of illness. Pathological study showed extensive fungal infiltration of periorbital structures and mycotic thrombosis of many blood vessels with associated necrosis and infarction of fat and extraocular muscles.

Diabetes Mellitus, Type 2↗

PubMed1984

The influence of distal environment on peripheral nerve regeneration across a gap.

Adult mice were divided into groups, all of which had the right sciatic nerve cut. In some groups, both the proximal and distal stumps were put into a plastic tube after various manipulations, while in other groups one or other stump was left out. Observations following survival periods of between 15 and 60 days showed that successful regeneration took place only in animals in which both proximal and distal stumps were present in the plastic tube and providing the cut ends of both stumps were facing each other. If the distal stumps were excluded from the tube or bent through 180 degrees, regeneration occurred initially, but was eventually ineffective. If the distal stump alone was inserted in the tube, a proliferation of Schwann cells, fibroblasts and regularly aligned collagen occurred. These findings support the hypothesis that the distal stump is essential for successful regeneration, but that in order to enhance it, the peripheral segment must be perfectly aligned with the proximal stump within the tube. Reasons for the necessity of such an alignment are discussed.

Animals↗

PubMed1984

Granular cell tumor of the fifth cranial nerve: further evidence for Schwann cell origin.

Granular cell tumors arising from the cranial nerves are rare. We describe a granular cell neoplasm of the fifth cranial nerve in a 66-year-old male. Light microscopic appearances included rows and clusters of cells with small peripheral nuclei and abundant eosinophilic cytoplasm. Ultrastructurally the cytoplasm of these cells contained numerous dense bodies, multivesicular bodies and vacuoles. In some areas tumor cells were intermingled with myelinated and unmyelinated nerve fibers showing the same relationships as do Schwann cells and nerve fibers. The association between tumor cells and axon seen in this case lends further support to the putative Schwann cell origin of this neoplasm.

Aged↗

PubMed1984

Autosomal dominant late onset cerebellar ataxia with myoclonus, peripheral neuropathy and sensorineural deafness: a clinicopathological report.

Three members of a family were affected by an autosomal dominant disorder comprising cerebellar ataxia, sensorineural deafness, myoclonus, and peripheral neuropathy. This is the second kindred with this syndrome reported to date. Necropsy of the proband showed loss of cells in the dentate nuclei, a reduced amount of cerebellar white matter, and pallor of the gracile tracts in the spinal cord.

Adult↗

PubMed1984

Long survival in subacute sclerosing panencephalitis.

A case is reported of a boy who at the age of 14 years developed subacute sclerosing panencephalitis. He deteriorated over a period of 9 months, improved greatly and remained stable for 7 years before relapse. The final deterioration to death extended over 6 years. During the whole period he was examined regularly and the electroencephalogram recorded at 3 to 6 monthly intervals. The brain was examined histologically after death. Electroencephalographic and pathological features are described.

Adolescent↗

PubMed1984

Regeneration of the perineurium across a surgically induced gap in a nerve encased in a plastic tube.

Sciatic nerves of mice were cut and the early regenerative stages were studied after the stumps had been encased within plastic tubes and kept separate by a gap of 5 mm. Only isolated cells were seen inside the tube after 7 days; after 12 days active regeneration and myelination were seen proximally; more distally, cells with long processes formed large spaces filled with collagen and less numerous Schwann cells. Zonulae occludentes and segments of basal lamina became more evident at a later stage. One month after the operation an almost complete regeneration of the nerve had taken place and perineurial cells were lined by a continuous basal lamina. The regeneration of the perineurium seemed to take place from fibroblasts; their cytoplasm as well as that of Schwann cells contained fibrillary material at this stage, sometimes in relation to segments of basal lamina. The results of this study indicate that both types of cells take part in the formation of endoneurial structures and that the early arrangement of fibroblasts contributes to the orderly longitudinal alignment of collagen fibrils.

Animals↗

PubMed1983

Reduced substance P in hereditary sensory neuropathy in the mf rat.

Mutilated foot (mf) is a mutant rat with an autosomal recessive sensory neuropathy. Affected animals become ataxic and their feet become mutilated. Morphological and quantitative studies have shown a reduced number of sensory ganglion cells and of cells of secondary sensory neurons. No degeneration was seen in the peripheral nervous system. Substance P (SP) is an undecapeptide which is thought to be involved in transmission of nociceptive information. Since mf rats show, in addition to ataxia, a decreased response to painful stimuli, SP immunoreactivity was examined. The density of SP staining was decreased at all levels of the spinal cord, mainly at cervical and lumbar levels and only in areas related to sensory pathways. In other areas of the spinal cord and in the substantia gelatinosa of the trigeminal tract, no reduction of SP staining was observed. The results further support the relationship between SP and transmission of pain stimuli. There are also many similarities between the appearance in mf rats and those in animals in which sensory afferents from dorsal root ganglia had been impaired with various methods, particularly in those treated from birth with capsaicin.

Afferent Pathways↗

PubMed1982

Improved myelination in nerve grafts from the leucodystrophic twitcher into trembler mice: evidence for enzyme replacement.

The possibility of the treatment of globoid cell leucodystrophy in the twitcher mouse by enzyme replacement was investigated using nerve grafts from affected animals into trembler hosts. The trembler mouse has no known enzyme deficiency but its peripheral nerves are hypomyelinated due to a Schwann cell abnormality and this defect represents a marker used in the present study to exclude the possibility of migration of Schwann cells from the host into the graft. Twitcher grafts were examined after periods ranging from 1 to 4 months. At all stages myelin sheaths were well formed and did not show signs of degeneration. Moreover the interstitial oedema, characteristic of the twitcher nerve, was greatly diminished in amount and no globoid cells were seen. These results were compared with previous studies done in vivo and in vitro in other types of lysosomal storage disease. We concluded that the improvement of the conditions of the myelin in the transplant is possibly due to enzyme replacement from the host.

Animals↗

PubMed1982

The pathology of Machado-Joseph disease. Report of a possible homozygous case.

The clinical and pathological findings in a boy suffering from Machado-Joseph disease are described. The patient was the son of two affected parents and signs first appeared at the age of 8 years. A younger brother also became affected at the age of 7. The patient presented all the characteristic features of the disease which consist of progressive cerebellar ataxia, pyramidal signs, progressive external ophthalmoplegia with variable degrees of extrapyramidal and peripheral signs. He died at the age of 15, after an unusually short duration of the disease. Pathological examination showed degeneration and mild gliosis of the substantia nigra, dentate, pontine and cranial nerve nuclei, anterior horns and Clarke's columns. Additional findings, not previously described were the involvement of sensory ganglia, intermediolateral columns and gracile and cuneate nuclei. It is suggested that the present case is homozygous for the gene of Machado-Joseph disease. The pattern of distribution of the pathological lesions and the sparing of some anatomical structures confirm our view that Machado-Joseph disease should be considered a distinct clinico-pathological entity within the group of the autosomal dominant ataxias.

Adolescent↗

PubMed1982

The pathogenesis of globoid cell leucodystrophy in peripheral nerve of the mouse mutant twitcher.

The twitcher mouse is affected by a disease with pathological features resembling those of human globoid cell leucodystrophy (Krabbe's disease): it also has an identical enzyme deficiency. The progress of the disease has been studied in peripheral nerves. Myelin sheaths develop normally until about the 15th day when the rate of myelination declines. Demyelination, first affecting paranodal regions is seen from the 10th-11th day before clinical signs appear. Krabbe-type inclusions are seen in macrophages and Schwann cells a few days later. Demyelination becomes extensive with increasing age, affecting fibres of all sizes, and axons rapidly remyelinate. Axons are not involved but quantitative studies show that they remain smaller than normal. Changes in twitcher nerves are compared to those in the neuropathy in human Krabbe's disease.

Animals↗