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Biomedical subjects

F Scaravilli

Publications and source records attributed to F Scaravilli.

At least 127 records · Page 7Linked to original sources

Differential neuropeptide expression after visceral and somatic nerve injury in the cat and rat.

The expression of neuropeptides galanin, vasoactive intestinal polypeptide (VIP) and substance P was compared after injury to somatic (sciatic, pudendal) and visceral (pelvic) nerves. Studies in normal rats and the mutant rat 'mutilated foot' suggested that galanin increases in sensory but not sympathetic fibres after sciatic nerve injury, while VIP appears to increase in both sensory and sympathetic fibres, and substance P to decrease in sensory fibres. A direct comparison of neuropeptide changes after somatic and visceral nerve injury was made in the cat dorsal sacral spinal cord, where both pudenal (somatic) and pelvic (visceral) afferents terminate. Four weeks after pudendal nerve transection in the cat there was an increase of VIP and galanin but decrease of substance P in the dorsal sacral cord, similar to the changes in lumbar dorsal cord after sciatic nerve section in the rat. In contrast, 4 weeks after pelvic nerve transection in the cat, galanin was unchanged in the ipsilateral dorsal sacral spinal cord, whereas VIP is known to decrease markedly and substance P to remain unchanged. There is thus differential peptide expression before and after injury in somatic and visceral systems, which may be regulated in part by the target organ. We have proposed that the neuropeptide changes occur in neurons that regulate development, maintenance and repair after injury, processes that may differ in somatic and visceral systems.

Animals↗

Prominent cortical atrophy with neuronal loss as correlate of human immunodeficiency virus encephalopathy.

A 25-year-old homosexual AIDS patient presented with progressive cognitive, motor and behavioral disturbances consistent with HIV encephalopathy. CT scans demonstrated progressive diffuse brain atrophy. Neuropathology showed predominant cortical changes including severe neuronal loss corroborated by morphometry. Only minimal changes were found in the white matter and basal ganglia. Immunocytochemistry for HIV stained occasional microglial cells more markedly in the cerebral cortex. This suggests that HIV infection of the brain may cause predominant cortical nerve cell loss, and that HIV encephalopathy is not necessarily due to white matter lesions.

AIDS Dementia Complex↗

Ischaemic myelopathy secondary to disseminated intravascular coagulation in AIDS.

A 39-year-old patient with AIDS presented with a rapidly progressive myelopathy with a partial Brown-Séquard syndrome. He died, 9 weeks after onset of the first neurological signs, from diffuse encephalopathy. Neuropathological examination revealed multiple, usually small, frequently haemorrhagic, infarcts or various ages and numerous fibrin thrombi in medium and small penetrating vessels and capillaries of the brain and spinal cord, characteristic of disseminated intravascular coagulation. There were no inflammatory changes. Immunohistochemical studies for human immunodeficiency virus, cytomegalovirus, varicella zoster virus, herpes simplex virus type 1 and type 2 were negative. Ischaemic spinal cord lesions due to disseminated intravascular coagulation may represent an unusual cause of focal, non-inflammatory, non-tumoral, myelopathic syndrome in AIDS.

Acquired Immunodeficiency Syndrome↗

Macrophages in human sensory ganglia: an immunohistochemical and ultrastructural study.

The paper describes the immunohistochemical and ultrastructural features of normal posterior root ganglia in a group of humans aged 1 day to 80 years and compares the findings with those seen in the ganglia of normal rats of various ages, some of which underwent permanent traumatic lesions of the sciatic nerve. In humans, cells with the immunohistochemical reactions of macrophages are present in small number at birth, most of them having an endoneurial position. Subsequently, their number increases and more of them are seen around neurons, where their processes intermingle with those of satellite cells. Ultrastructural studies confirm that, in addition to interstitial cells, a small number of cells in satellite position have features of mesenchymal cells. In this respect, human sensory ganglia differ from those of rodents and this difference may explain why no nodules of Nageotte can be found either in ageing animals or after a permanent damage to the nerve has produced considerable cell loss. Other features observed in human ganglia, but absent in rats, are multiple layers of satellite cells surrounding each neuron and desmosome-like structures between satellite cell processes. Previous studies describing maturation of the satellite-nerve cell complex in animals are confirmed. In addition, the present investigation shows that, in human ganglia, satellite cells acquire a more elaborate structure than in rodents. It is also suggested that mesenchymal cells may play a role in the trophism of nerve cells and their removal after irreversible damage.

Adolescent↗

Strongyloides stercoralis hyperinfection in an HIV positive patient.

A 25 year old British man of previous good health presented with persistent generalised lymphadenopathy and was found to be human immunodeficiency virus (HIV) antibody positive. Three years later after weight loss and loose stools Strongyloides stercoralis was identified in the latter and successfully treated with thiabendazole. Shortly afterwards, a further episode again responded rapidly, but was swiftly followed by a final and fatal illness with severe debility and metabolic imbalance unresponsive to all treatment. Necropsy showed widespread and heavy strongyloidiasis with pulmonary haemorrhage, bronchopneumonia, and meningitis.

Adult↗

Destructive lesions in demyelinating disease.

Three cases are presented in which clinical and radiological features suggested the diagnosis of glioma but surgical biopsy revealed a demyelinating process, with tissue destruction and cyst formation in two. One patient had clinically definite multiple sclerosis. Two had probable acute disseminated encephalomyelitis. Treatment with high dose steroids is appropriate when there is clinical or investigative evidence to suggest the presence of demyelinating disease, before deciding on biopsy.

Adolescent↗

Fulminating multiple sclerosis-like leukoencephalopathy revealing human immunodeficiency virus infection.

A 66-year-old French homosexual man and a 42-year-old Brazilian man with no known risk factors for HIV infection developed headaches, asthenia, and neurologic episodes of abrupt onset. CT showed multiple hypodense, nonenhancing lesions. Serology for HIV was positive. They died respectively 2 months and 1 month after onset of the illnesses. Autopsy in both cases showed multiple, well-demarcated, demyelinating foci in the white matter of the cerebral hemispheres, brainstem, and cerebellum with histologic features characteristic of recent plaques of multiple sclerosis. There were no multinucleated giant cells or microglial nodules. Immunostaining for HIV was negative. Although a random coincidence of MS and HIV infection cannot be ruled out, the close temporal relationship between the 2 disorders suggests a possible etiologic association.

Adult↗

Peripheral neuropathy in hypereosinophilic syndrome with vasculitis.

A 53-year-old woman with non-productive cough of unexplained aetiology for two years, developed a sub-acute symmetrical polyneuropathy involving all four limbs, accompanied by fever, cutaneous rash and myalgia in lower limbs. Laboratory studies revealed a leukocytosis with 70% eosinophils and excluded any cause for the hypereosinophilia. An echocardiogram showed increase in thickness of the atrial septum. Motor and sensory conduction velocity were reduced in ulnar and median nerve and unrecordable in peroneal and tibial nerves. A sural nerve biopsy showed an axonal degeneration involving myelinated and unmyelinated fibers as well as a vasculitis with fibrinoid necrosis and perivascular infiltration of eosinophils. There was considerable clinical and laboratory improvement with the use of steroids. The differential diagnosis between idiopathic hypereosinophilic syndrome and other disorders known to course with vasculitis and hypereosinophilia is discussed.

Biopsy↗

Studies of vasoactive intestinal polypeptide expression in injured peripheral neurons using capsaicin, sympathectomy and mf mutant rats.

The increased expression of vasoactive intestinal polypeptide (VIP) in injured peripheral neurons was studied. In contrast to substance P, there was a marked increase, and maintained fast axonal transport, of VIP in rat sciatic nerve after peripheral axotomy. Local capsaicin application to the nerve trunk failed to inhibit the injury-induced VIP increase, and capsaicin even increased VIP levels when applied locally to uninjured nerves. Pharmacological sympathectomy showed that some of the peripheral VIP increase may occur in post-ganglionic sympathetic fibres. The VIP increase after injury appeared unaffected in the mf mutant rat, in spite of its loss of lumbar dorsal root ganglion cells. VIP-staining fibres in the epi- and peri-neurium and perivascular plexuses of sciatic nerve showed an increase in number in parallel with the changes of the nerve VIP content. These findings suggest that sensory and sympathetic nerve fibres expressing VIP after injury play a role in the regulation of blood flow to nerves, and in the pathophysiological processes in nerve and dorsal spinal cord which follow peripheral nerve injury.

Animals↗

Movement disorders in mitochondrial myopathies. A study of nine cases with two autopsy studies.

Of 85 consecutive patients with mitochondrial myopathy, 29 had clinically significant central nervous system involvement. Nine of these had movement disorders that included dystonia, chorea, parkinsonism, and myoclonus. Autopsy studies of one patient with ataxia, dementia, and parkinsonism followed by dystonia showed the features of olivopontocerebellar atrophy with additional degenerative changes in the basal ganglia. Postmortem in a further case with myoclonus, deafness, muscle weakness, retinopathy, and ataxia showed symmetrical mineralisation of the striatopallidodentatal system.

Adult↗

Neurofibromatous neuropathy.

Three cases of chronic distal sensorimotor neuropathy are described in patients with neurofibromatosis. One had type 2 or central neurofibromatosis with a chromosome 22 deletion; the precise form of the disease was not established in the other two. A striking clinical feature was a diffuse nodular enlargement of the peripheral nerves. Nerve biopsies from all three cases demonstrated the presence of neurofibromatous pathology. Neurofibromatous neuropathy constitutes a rare manifestation of neurofibromatosis, related to diffuse neurofibromatous changes in the peripheral nerves.

Adult↗