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PubMedDate not supplied

[Demyelinating pseudotumoral lesion prior to a primary cerebral lymphoma].

INTRODUCTION: Some case of demyelinating pseudotumoral lesions preceding the appearance of primary cerebral lymphoma have been reported. The relation between the two conditions is not known. We report the case of a woman in whom a demyelinating pseudotumoral lesion had been diagnosed on biopsy and who developed a primary cerebral lymphoma 13 months later. CLINICAL CASE: In October 1997 a 38 year old woman presented with a secondarily generalized focal motor seizure. Neuroimaging showed a left frontal tumour with marked oedema and uptake of contrast medium. Based on the clinicoradiological suspicion of a primary cerebral tumour or metastasis, treatment was started with dexamethasone. Approximately two weeks later a stereotaxic biopsy was done, in which there was demyelination with conservation of the axons and perivascular inflammatory infiltration with polyclonal T and B lymphocytes. The diagnosis was 'a pseudotumoral form of a demyelinating disease'. Thirteen months later the patient had episodes of falling to the floor, followed by subsequent slight confusion and difficulty in speaking. On neuroimaging studies (cerebral CAT and MR) there was a tumour of the left basal ganglia, considerable oedema and homogeneous marking following the injection of contrast. Anatomopathological study of the lesion showed a B cell lymphoma. CONCLUSION: In cases of pseudotumoral demyelinating lesions the possibility of a primary cerebral lymphoma of the central nervous system must be remembered.

Adult↗
PubMed2001

Acquired inflammatory demyelinating neuropathies.

The acquired demyelinating neuropathies can be divided into those with an acute onset and course and those with a more chronic course. The acute neuropathies present as Guillain-Barré syndrome and include acute inflammatory demyelinating polyradiculoneuropathy (AIDP), Miller Fisher syndrome, acute motor axonal neuropathy (AMAN), acute motor and sensory axonal neuropathy (AMSAN), and acute pandysautonomia. The chronic neuropathies are collectively known as chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) and include MADSAM (multifocal acquired demyelinating sensory and motor neuropathy, also know as Lewis-Sumner syndrome) and DADS (distal acquired demyelinating symmetric neuropathy) as variants. The clinical features, pathology, pathogenesis, diagnosis, treatment, rehabilitation, and prognosis of these neuropathies are discussed.

Acute Disease↗
PubMed2002

[A clinicopathological study of demyelination pseudotumors of the brain].

OBJECTIVE: To study the clinicopathological characteristics diagnosis, differential diagnosis and etiology of demyelination pseudotumors of the brain. METHODS: The clinical features, CT, MRI scan findings, corticosteroid therapeutic effects and follow-up data of 3 cases of demyelination pseudotumors of the brain were analysed, and pathological changes were observed by histologic (HE, Luxol fast blue and Bodian) and immunohistochemical (S-P method) techniques. RESULTS: The acute onset of demyelination pseudotumors appeared to be more predominant in our data. Clinical manifestations included headache, vomiting, a depressed conscious level, dysphasia, and paresis. CT, MRI scans showed solitary or multiple lesions in cerebral hemisphere. All the patients presented excellent response to steroid treatment. Follow-up for a period of 6 to 31 months, revealed the absence of progression or recurrence. The pathological changes were mainly located in both cerebral hemispheres, in which there were relative axonal preservation in foci loss of myelin, reactive gliosis, profuse perivascular lymphocytic infiltration and mixtures of foamy macrophages. CONCLUSION: Demyelination pseudotumor is a distinct clinicopathologic encephalitic entity. The findings of this study suggest that the cause of tumefactive demyelination may be related to an allergic reaction triggered by viral infection.

Adolescent↗
PubMedDate not supplied

[Virus and demyelination: why suspect that a virus may be involved in the aetiology of multiple sclerosis?].

INTRODUCTION: Epidemiological data indicate that environmental factors, possibly infections, are associated with the development of multiple sclerosis. Different viruses are known to produce demyelination in natural and experimental animal infections. In humans some virus cause acute or chronic diseases that course with central nervous system demyelination. A series of virus have been claimed to be etiological agents of multiple sclerosis, although a causal role for any of them has so far been demonstrated. METHOD: The mechanisms of viral demyelination are diverse,ranging from direct destruction of infected oligodendrocytes to triggering autoimmune responses without virus multiplication in target cells. The potential indirect mechanisms of viral demyelination and the heterogeneous histopathology shown in multiple sclerosis patients, suggesting an heterogeneus etiology, might explain why not a single virus has been as yet identified as the cause of this disease. CONCLUSIONS: Viral infections that cause demyelination in animals and humans are briefly reviewed, focusing on the potential myelin destruction mechanisms and obstacles to the identifying viruses that might cause multiple sclerosis.

Animals↗
PubMed2003

[POEMS Syndrome with central and peripheric nervous system demyelination].

POEMS syndrome is characterized by polyneuropathy, organomegaly, endocrinopathy, monoclonal protein and skin changes. This polyneuropathy belongs to the chronic inflammatory demyelinating polyradiculoneuropathies (CIDP) group. Sporadic reports have emphasized the clinical association between CIDP and central nervous system (CNS) demyelination, but as far as we know not in the context of POEMS syndrome. We report the case of a 67 years old patient who developed POEMS syndrome associated to Castleman's disease, characterized by demyelinating polyradiculoneuropathy, hepatosplenomegaly, mediastinal and supraclavicular adenopathies and monoclonal IgG lambda gammapathy. Cranial magnetic resonance imaging disclosed diffuse alteration of the cerebral white matter highly suggestive of demyelination. CNS demyelination can be another feature of POEMS syndrome. Cranial MRI should be performed in patients with POEMS syndrome in order to verify this new feature.

Aged↗
PubMed2004

[Comparative analysis of clinical and neurophysiological indices in patients with multiple sclerosis and acute demyelinating polyneuropathy].

A comparison study of some clinical and neuropsychological indices in two demyelinating disorders--multiple sclerosis (17 patients, mean age 31.6 years) and inflammatory demyelinating polyneuropathy (7 patients, mean age 49.5 years) was conducted, using electromyography with registration of impulse velocity conduction along the nerve and M-responses as well as of the parameters of movement units potentials. The data obtained suggest the presence of demyelinating lesions of central and peripheral nervous systems, namely, symptoms of axonal demyelinating polyneuropathy with the prevalence of demyelinating process, its dissemination and generalization, in both disorders.

Acute Disease↗
PubMed2006

[Multiple sclerosis in children: clarifying its place among the demyelinating spectrum].

Multiple sclerosis (MS) is an autoimmune disease caused by the destruction of the myelin layer and the nervous fibers, and secondary by a progressive neuronal damage. It is characterized by episodes of demyelination disseminated in time and space in different areas of the white matter of the CNS which includes periventricular region, spinal cord, brain stem, cerebellum and optical nerve. Due to the confusing differential diagnosis of MS in children with other demyelinating diseases such as ADEM, it is important to reach this diagnosis when there is proof of white matter lesions disseminated in time and space that cannot be explained by any other mechanisms or pathologies. The goal of this paper is to review the diagnostic parameters used for MS in the pediatric age, the dilemmas regarding the validity of diagnostic criteria, clinical manifestations, differentiation of other demyelinating diseases, and the diagnostic process. MS although infrequent, is a valid diagnosis among the spectrum of childhood inflammatory demyelinating diseases. The clinical presentation might be indistinguishable from a multifocal acute disseminated encephalopathy or could be presented with just focal signs. A reasonable clinical judgment and the practice of laboratory tests confirm or rule out the diagnosis. It is not possible to differentiate between ADEM and MS in a first episode, nor by the clinical, the CSF, neither the neuroimaging. There are still needed consensus criteria both clinical and laboratory test. There are many question still to be answered using prospective studies, and standardized clinical measures that will allow the delimitation of the demographic, neurological, and neuropsychological aspects of the MS and other form of acquired demyelinating diseases in children.

Acute Disease↗
PubMed1987

Class II-restricted T cell responses in Theiler's murine encephalomyelitis virus (TMEV)-induced demyelinating disease. I. Cross-specificity among TMEV substrains and related picornaviruses, but not myelin proteins.

Following intracerebral inoculation of Theiler's murine encephalomyelitis virus (TMEV), susceptible mouse strains develop a chronic demyelinating disease characterized by mononuclear cell-rich infiltrates in the central nervous system. Current evidence strongly supports an immune-mediated basis for myelin breakdown, with an effector role proposed for TMEV-specific, major histocompatibility class II-restricted delayed-type hypersensitivity, which temporally correlates with disease onset and remains chronically elevated in susceptible mice. This study examined the fine specificity of class II-restricted T cell responses in TMEV-infected mice to better define the relevant virus-encoded T cell determinant(s) responsible for triggering the demyelinating process, and to determine if class II-restricted neuroantigen-specific autoimmune responses could be detected in mice with TMEV-induced demyelination. The data clearly show that T cell responses in TMEV-infected mice are directed against determinants shared by closely related TMEV strains and are cross-reactive with related picornaviruses, such as encephalomyocarditis virus. In contrast, class II-restricted autoimmune responses against syngeneic mouse spinal cord homogenate and the two major protein components of myelin, myelin basic protein and proteolipid protein, are not demonstrable in susceptible SJL/J mice undergoing chronic TMEV-induced demyelinating disease, but are readily seen in SJL/J mice displaying chronic, relapsing experimental allergic encephalomyelitis. Cross-reactivity (or lack thereof), as determined by functional T cell analyses, was found to correlate with the extent of exact amino acid homology between the TMEV capsid proteins, the two neuroantigens, and related picornaviruses. The data thus do not support a major role for autoimmune responses against myelin proteins in TMEV-induced demyelinating disease, but are consistent with our previously proposed hypothesis that TMEV-specific T cell responses constitute a major effector mechanism of myelin breakdown.

Animals↗
PubMed1987

Comparative analysis of coronavirus JHM-induced demyelinating encephalomyelitis in Lewis and Brown Norway rats.

Lewis and Brown Norway rats were infected at different ages with the neurotropic murine coronavirus strain, JHM and the resultant central nervous system diseases were studied. Suckling rats of both strains came down with a fatal, acute encephalomyelitis. Weanling Lewis rats developed a subacute demyelinating encephalomyelitis which neuropathologically revealed changes of an immunopathologic reaction. In contrast, Brown Norway rats developed a clinically silent subacute demyelinating encephalomyelitis with a persistent JHM virus infection which was less severe and quite different from the subacute demyelinating encephalomyelitis in Lewis rats with respect to size, distribution, and localization of the demyelinating plaques as well as the type of infiltrating cells. In addition, infected Lewis rats showed a pronounced lymphocyte proliferation to myelin basic protein and JHM virus whereas lymphocytes from infected Brown Norway rats did not react to these two antigens. These observations demonstrate the pathogenetic importance of host factors in the development of virus-induced demyelination.

Aging↗
PubMed1987

Rapid axonal transport in focally demyelinated sciatic nerve.

Focal demyelination was produced in rat sciatic nerve by unilateral intraneural injection of anti-galactocerebroside serum. A functional lesion was confirmed by the presence of nerve conduction block. Histologically, this corresponded to demyelination of 50-70% of the fibers in nerve cross sections; axonal structures appeared intact. At the time of maximal demyelination (7 d), 35S-methionine or 3H-fucose was injected bilaterally into the spinal cord ventral horn. At later times (5 hr-7 d), the sciatic nerve was removed and radioactivity in successive nerve segments was quantitated. The transport rates (approximately 260 mm/d) and the composition of transported proteins and glycoproteins (separated on 7-15% polyacrylamide gradient gels) were not altered in lesioned nerves relative to contralateral control nerves. Light microscopic autoradiographic analysis revealed a similar localization of axonally transported and deposited glycoproteins in demyelinated and control fibers. Initially (8 hr), the majority of label was over axons. Labeled glycoproteins remaining in the nerve after 1 week were retained mainly in axolemmal regions. We conclude that acute focal primary demyelination does not lead to major alterations in the transport or deposition of newly synthesized macromolecules.

Animals↗
PubMed1988

Successful therapy of Theiler's virus-induced demyelination (DA strain) with monoclonal anti-Lyt-2 antibody.

The effects of therapy with mAb to T cell subsets were studied in mice with Theiler's murine encephalomyelitis virus-induced demyelination. mAb GK1.5 (directed at class II-restricted T cells) and mAb 2.43 (directed at class I-restricted T cells) depleted the appropriate subset of T cells in lymph nodes, spleens, and peripheral blood for 6 to 8 wk after a single i.p. injection of 1 mg of purified mAb. Early treatment with mAb GK1.5 (days -1, 0, and +1 relative to virus injection) resulted in death, encephalitis, and increased demyelination in the majority of animals tested. Treatment with mAb 2.43 resulted in less meningeal inflammation and fewer demyelinating lesions in the spinal cord, irrespective of whether the mAb was given early or after demyelinating disease was established (days 15, 16, and 17). Beneficial response to mAb therapy did not correlate with titers of virus isolated from the central nervous system or serum. These results indicate an important role of class II-restricted T cells during early disease in preventing overwhelming encephalitis; class I-restricted T cells may be critical during demyelination.

Animals↗
PubMed1988

Interconnection of demyelination processes and inflammation in the dynamics of experimental allergic encephalomyelitis.

Using a new method for the simultaneous demonstration of myelin breakdown products and cell elements in the demyelinated nervous tissue, a number of previously unknown regularities were revealed concerning interconnection between demyelination processes and inflammation in the dynamics of experimental allergic encephalomyelitis (EAE). Alterations in osmophilia and in size of myelin breakdown products in the demyelination foci are demonstrated to be the most essential in the EAE pathomorphology, a certain type of cellular reaction corresponding to each stage of periaxonal changes. A close relationship was found between demyelination processes and inflammation which determines the structure of the demyelination foci at various stages of the disease.

Animals↗
PubMed1985

Theiler's murine encephalomyelitis virus (TMEV)-induced demyelinating disease in mice is influenced by the H-2D region: correlation with TEMV-specific delayed-type hypersensitivity.

Intracranial inoculation of Theiler's murine encephalomyelitis virus (TMEV) leads to the development of a chronic demyelinating disorder in certain mouse strains. Development of this disease is controlled by at least two unlinked genes, one of which is within or linked to the H-2 complex. In the present study, we attempted to map the relevant H-2 loci involved in susceptibility to TMEV-induced demyelination using crosses between SJL and several congenic H-2 recombinant mouse strains bearing different combinations of MHC genes from the susceptible H-2s and resistant H-2b haplotypes all on the C57BL/10 strain background. The data suggest that the D region of the H-2 complex strongly influences development of the demyelinating disease because increased susceptibility correlates well with homozygosity for H-2s alleles in the D region, but not in K or I-A. In addition, we also attempted to correlate certain immune and nonimmune pathophysiologic parameters with the development of clinical disease. Specifically, central nervous system TMEV titers and TMEV-specific humoral and cellular [delayed-type hypersensitivity (DTH) and T cell proliferative (Tprlf)] responses were examined. The data show that TMEV-induced demyelinating disease did not correlate with either CNS TMEV titers or TMEV-specific humoral or Tprlf responses but did correlate closely with the presence of high levels of TMEV-specific DTH. Collectively, our findings demonstrating a strong correlation between disease incidence, the presence of particular H-2D region genotypes, and high levels of TMEV-specific DTH in susceptible strains (as well as previous findings showing predominant mononuclear cell infiltrates in CNS demyelinating lesions) support the hypothesis that the disease is immune mediated rather than a result of direct cytolytic effects of virus infection.

Animals↗
PubMed1981

Murine central nervous system infection by a viral temperature-sensitive mutant: a subacute disease leading to demyelination.

Temperature-sensitive (ts) mutants of viruses may represent an important mechanism for viral persistence. Ts mutants of different complementation groups of vesicular stomatitus virus (VSV) have shown various disease patterns in infected mice which were at variance with the clinical and pathologic features of wild-type virus infection. To investigate whether neurovirulence of different ts mutants was dependent on the individual mutant or on the biochemical defect(s) common to all members of a complementation group, we infected mice with ts G32 VSV, a mutant of the same complementation group III as the previously described ts G31 VSV. Pathologic changes in infected mice were sharply different from those produced by ts G31 VSV and actually similar to those produced by ts G41 VSV, a member of Complementation Group IV, also previously described. These results suggest that the biologic behavior of ts mutants is dependent on the individual characteristics of each mutant. The most important alterations by ts G32 VSV were in the white matter of brain and spinal cord, where extensive inflammatory demyelination was observed. Lack of inflammation and demyelination in similarly infected nude mice would suggest that, in this infection, demyelination is produced by the host immune response rather than by direct viral myelinolytic activity. Such findings are similar to those we described in other viral infections and support the hypothesis of a common host-mediated pathway leading to demyelination in a variety of unrelated viral infections. These conclusions may have relevance to human demyelinating diseases.

Animals↗
PubMed1977

Lead neuropathy. 1) Morphometry, nerve conduction, and choline acetyltransferase transport: new finding of endoneurial edema associated with segmental demyelination.

Morphometric and pathologic studies along the length of the peripheral nervous system were obtained in groups of rats fed 4% lead carbonate for 3 and 6 months and in match-fed controls. The number and diameter histograms of L6 cytons of spinal ganglia and of myelinated fibers of proximal and distal portions of peroneal and sural nerve were not significantly different from the control groups. On the other hand, segmental demyelination occurred approximately as frequently in proximal as in distal parts of nerves. At 3 months approximately 1/3 of teased myelinated fibers showed changes of segmental demyelination (Condition C), or of remyelination after segmental demyelination (Condition F) or of both segmental demyelination and of remyelination (Condition D), while at 6 months more than 4/5ths of fibers showed these changes. As expected, regression lines of axonal area on number of lamellae of myelin, were less steep in nerves of rats fed on lead for 6 months as compared to controls. Axonal transport of choline acetyltransferase in lead neuropathy did not differ from that in control rats. As expected from the studies of others, conduction velocity of myelinated fibers of caudal nerve were low. A new finding was the often quite striking increase of transverse fascicular area of peripheral nerves. This was due to edema which appeared to develop at about the time of onset os segmental demyelination. Although the edema may be an epiphenomenon, it could be an important observation bearing on the development of lead neuropathy. It would be important to know next whether or not the blood nerve barrier is altered in lead neuropathy.

Animals↗
PubMed1980

Schwann cell remyelination and recurrent demyelination in the central nervous system of mice infected with attenuated Theiler's virus.

Theiler's murine encephalomyelitis virus (TMEV) infection produces a chronic demyelinating disease in mice, and myelin breakdown appears to be immune-mediated. By using an attenuated TMEC strain, WW virus, to infect mice, the course of the disease was slowed and the severity of the inflammatory and glial responses were reduced. In this circumstance, most of the demyelinating lesions showed extensive remyelination, predominantly by Schwann cells. In addition, it was demonstrated that there was recurrent demyelinating activity in the central nervous system (CNS) of infected animals. It is suggested that the rapidity and intensity of demyelinating lesions may influence the potential for remyelination and that Schwann cell participation may be a more important mechanism of myelin repair than it is now thought to be. The fact that there is a recurrent demyelination in TMEV infection increases its relevance as an experimental animal model for multiple sclerosis.

Animals↗
PubMed1995

Inhibition of Theiler's virus-mediated demyelination by peripheral immune tolerance induction.

Theiler's murine encephalomyelitis virus (TMEV), a member of the cardiovirus subfamily of the Picornaviridae, is a natural pathogen of mice. Thirty to 60 days following intracerebral infection with TMEV, susceptible inbred mouse strains develop a chronic, progressive, T cell-mediated inflammatory demyelinating disease of the central nervous system (CNS) characterized by spastic hind limb paralysis and a lifelong persistent CNS virus infection. We have examined the effect of peripheral virus-specific tolerance on the development of demyelinating disease. Treatment of SJL/J mice with TMEV-coupled, ethyl carbodiimide-treated splenocytes either before or after infection with live TMEV prevented the development of clinical disease, including inflammation and demyelination in the CNS. Prevention of clinical disease was paralleled by significant reductions in virus-specific immune responses, including delayed type hypersensitivity and T cell proliferative responses. Tolerance induction resulted in a significant reduction in the absolute numbers of mononuclear cells infiltrating the CNS, particularly the CD4+IL-2R+ T cell subset, 3, 5, and 8 wk postinfection. In contrast, tolerance induction had no effect on the numbers of CD8+IL-2R+ T cells infiltrating the CNS. Treatment with TMEV-coupled splenocytes failed to prevent the development of relapsing experimental autoimmune encephalomyelitis, demonstrating the specificity of in vivo tolerance induction. Prevention of demyelinating disease did not correlate with the increased TMEV-specific Ab responses observed in tolerized mice. These results indicate that induction of immune tolerance to TMEV can down-regulate a chronic immunopathogenic disease directed against virus Ag persisting in the CNS that normally results in a progressive demyelinating disease similar to multiple sclerosis.

Animals↗
PubMed1994

[A case of acute disseminated encephalomyelitis with pathologically-proven acute demyelinating lesion in the peripheral nervous system].

We present a case of acute severe demyelination affecting both CNS and PNS with pathological evidence. A 62-year-old man presented with acute onset of coma preceded by common cold-like symptoms. He was diagnosed as acute disseminated encephalomyelopathy (ADEM), and died of brain herniation in two weeks. At autopsy, in addition to severe demyelination of the white matter of the central nervous system, there was widespread acute demyelinating process in the peripheral nervous system. Myelin destruction by macrophage was most conspicuous in the spinal nerve root with preservation of the axon cylinder. So far the association of hypertrophic demyelinating neuropathy was reported in cases of multiple sclerosis. However, there have not been any papers in which substantial involvement of both CNS and PNS in cases of ADEM except for the clinical report by Amit. Antigenic cross-reactivity between CNS and PNS against myelin proteins or other antigens like glycolipid may elicit similar immune responses producing demyelination.

Acute Disease↗