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Query: UMLS:C0014070 (encephalomyelitis)
 13,017 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Neuropathological observations were made in 200 clinically suspected cases of bovine spongiform encephalopathy (BSE) in which pathognomonic vacuolar changes were absent. Routine histological and immunocytochemical techniques were applied to formalin-fixed, paraffin-embedded sections of the central nervous system. Significant neuropathological findings were detected in 85 (42.5 per cent) cases. The most frequent lesion, detected in 46 (23 per cent) cases, was a focal white matter vacuolation principally affecting the substantia nigra, but its clinical significance was unclear. Listeriosis was diagnosed in 17 (8.5 per cent) cases. In three of seven cases of non-suppurative encephalitis, lesions suggested sporadic bovine encephalomyelitis, a disease not previously reported in the UK. Suppurative thromboembolic or granulomatous lesions accounted for other inflammatory changes. Neuroectodermal tumours were present in five cases (2.5 per cent); three were identical in form and considered to be atypical ependymoma. Cerebrocortical necrosis, oedema or both were detected in four cases. The remaining cases (4.5 per cent), comprised those in which the changes were minor and of doubtful significance. Incidental pathological findings included occasional degenerating or vacuolated neurones, which occurred in the red nucleus in 105 brains, in the habenular nucleus in 71 brains, and singly at other sites in 17 brains. In sections of 37 brains immunostained with antiserum to prion protein (PrP), no evidence of PrP accumulation was found, providing some evidence that the series did not contain bovine prion disease cases which, based on the histological diagnosis, had given a false negative result. It is suggested that, of 115 cases (57.5 per cent) which lacked significant histological lesions, some were suffering from metabolic disorders. The study identified diseases and lesions which feature in the differential diagnosis of BSE. Their more accurate diagnosis may become particularly important if, as predicted, the BSE epidemic declines.
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PMID:Neuropathological findings in cattle with clinically suspect but histologically unconfirmed bovine spongiform encephalopathy (BSE). 831 53

Extracellular fluid in the central nervous system (CNS) is composed of cerebrospinal fluid (CSF), derived from the choroid plexus, and of interstitial fluid (ISF) in gray and white matter. Investigation of CSF plays a significant role in diagnosis and management of neurological disease and pathologies involving the CSF have important effects on the CNS itself. Hydrocephalus has many causes; clinical effects are due to a mixture of obstruction to CSF flow and damage to periventricular white matter with CSF edema, axonal loss and gliosis. Meningitis and subarachnoid hemorrhage are mainly confined to the subarachnoid space emphasising how this compartment is separated from the CNS by the pia mater and glia limitans; brain damage results from thrombosis of leptomeningeal vessels and infarction of CNS tissue. ISF from white matter appears to drain mainly to CSF, but ISF from gray matter drains along periarterial pathways in CNS and meninges, to lymph nodes in experimental animals, and probably in humans. Beta-amyloid in Alzheimer disease and prion proteins accumulate in the extracellular spaces of gray matter and in periarterial ISF drainage pathways as cerebral amyloid angiopathy, emphasising the role of periarterial drainage for the elimination of high molecular weight substances from the brain, possibly to regional lymph nodes. Lymphatic drainage of ISF drainage plays a major role in B- and T-lymphocyte mediated immune reactions in the CNS in animals. By analogy with experimental autoimmune encephalomyelitis, lymphatic drainage of brain antigens in ISF from the human CNS may play a key role in the pathogenesis of Multiple Sclerosis.
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PMID:Pathology of cerebrospinal fluid and interstitial fluid of the CNS: significance for Alzheimer disease, prion disorders and multiple sclerosis. 978 39

Viral infections of the adult are fortunately rare conditions but may carry serious clinical sequelae. Infection is usually acquired by haematogenous spread during a systemic viral illness and may be acute, subacute or chronic. The pathological basis of neuronal degeneration and attempt to repair is common to all illnesses and diagnosis is generally made by analysis of the pattern of disease. Magnetic resonance imaging is now the mainstay of imaging diagnosis. Acute infections include encephalitis due to a wide range of infecting agents and outcome depends on the severity of the acute episode. Subacute and chronic infections, including HIV encephalopathy, most often produce a progressive leucoencephalopathy and ultimately cerebral atrophy. Additionally, disease may also be immune mediated, that most closely associated with viral infection being acute disseminated encephalomyelitis, which is usually a monophasic illness. Finally, prion diseases are characterised by long incubation period and progressive course, leading to death.
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PMID:Cranial viral infections in the adult. 1474 62

The concept of experimental allergic encephalomyelitis (EAE) being linked to both rabies post-vaccination encephalomyelitis and multiple sclerosis (MS) has raised the intriguing question whether animal studies carried out for the induction and transmission of transmissible spongiform encephalopathies (TSEs) using brain antigens including prions do have a similar immunopathogenetic mechanism. Although an essential link between autoimmunity and MS has been well established, its role in the pathogenesis of TSEs is generally lacking. However, auto-antibodies to myelin proteins and/or other neuronal antigens such as neurofilaments and prion proteins have been reported in animals with bovine spongiform encephalopathy (BSE) and scrapie as well as in patients with Creutzfeld-Jakob disease (CJD) and kuru. Acinetobacter has been suggested as a possible triggering microbial factor in the initiation of the autoimmune responses in these diseases because bacterial molecular sequences resemble brain antigens, especially in animals affected with BSE and patients with MS and CJD. These possibilities need to be evaluated further with longitudinal prospective studies carried out on larger numbers of animals or humans with such diseases. The transplantation of saline suspensions of brain homogenates will evoke immunological responses and therefore, the results in the study of MS and other neurological diseases have to be interpreted with caution.
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PMID:From rabies to transmissible spongiform encephalopathies: an immune-mediated microbial trigger involving molecular mimicry could be the answer. 1692 Feb 76

During the years or decades of prion disease incubation, at-risk individuals are certain to encounter diverse pathological insults, such as viral and bacterial infections, autoimmune diseases, or inflammatory processes. Whether prion disease incubation time and clinical signs or otherwise the pathology of intercurrent diseases can be affected by the coinfection process is unknown. To investigate this possibility, mice infected with the scrapie agent at both high and low titers were subsequently induced for experimental autoimmune encephalomyelitis, an immune system-mediated model of central nervous system (CNS) inflammation. We show here that co-induced mice died from a progressive neurological disease long before control mice succumbed to classical scrapie. To investigate the mechanism of the co-induced syndrome, we evaluated biochemical and pathological markers of both diseases. Brain and spleen PrP(Sc) levels in the dying co-induced mice were comparable to those observed in asymptomatic scrapie-infected animals, suggesting that co-induced disease is not an accelerated form of scrapie. In contrast, inflammatory markers, such as demyelination, immune cell infiltrates, and gliosis, were markedly increased in co-induced mouse spinal cords. Activated astrocytes were especially elevated in the medulla oblongata. Furthermore, PrP(sc) depositions were found in demyelinated white matter areas in co-induced mouse spinal cords, suggesting the presence of activated infected immune cells that infiltrate into the CNS to facilitate the process of prion neuroinvasion. We hypothesize that inflammatory processes affecting the CNS may have severe clinical implications in subjects incubating prion diseases.
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PMID:Fatal neurological disease in scrapie-infected mice induced for experimental autoimmune encephalomyelitis. 1762 90

Prion diseases, which can manifest by transmissible, sporadic or genetic etiologies, share several common features, such as a fatal neurodegenerative outcome and the aberrant accumulation of proteinase K (PK)-resistant PrP forms in the CNS. In infectious prion diseases, such as scrapie in mice, prions first replicate in immune organs, then invade the CNS via ascending peripheral tracts, finally causing death. Accelerated neuroinvasion and death occurs when activated prion-infected immune cells infiltrate into the CNS, as is the case for scrapie-infected mice induced for experimental autoimmune encephalomyelitis (EAE), a CNS inflammatory insult. To establish whether the immune system plays such a central role also in genetic prion diseases, we induced EAE in TgMHu2ME199K mice, a line mimicking for late onset genetic Creutzfeldt Jacob disease (gCJD), a human prion disease. We show here that EAE induction of TgMHu2ME199K mice neither accelerated nor aggravated prion disease manifestation. Concomitantly, we present evidence that PK-resistant PrP forms were absent from CNS immune infiltrates, and most surprisingly also from lymph nodes and spleens of TgMHu2ME199K mice at all ages and stages of disease. These results imply that the mechanism of genetic prion disease differs widely from that of the infectious presentation, and that the conversion of mutant PrPs into PK resistant forms occurs mostly/only in the CNS. If the absence of pathogenic PrP forms form immune organs is also true for gCJD patients, it may suggest their blood is devoid of prion infectivity.
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PMID:Genetic prion disease: no role for the immune system in disease pathogenesis? 2466 14

Viral infections of the central nervous system (CNS) range in clinical severity, with the most severe proving fatal within a matter of days. Some of the more than 100 different viruses known to affect the brain and spinal cord are neurotropic with a predilection for producing CNS infection. The host response to viral infection of the CNS is responsible for the pathophysiology and imaging findings seen in affected patients. Viral CNS infections can take the form of meningitis, encephalitis, encephalomyelitis, or, when involving the spinal cord and nerve roots, encephalomyeloradiculitis. In 1982, an infectious particle termed a prion that lacked nucleic acid and therefore was not a virus was reported to produce the fatal neurodegenerative disease Creutzfeldt-Jakob disease and related disorders. These prion diseases produce characteristic neuroimaging findings that are distinct from those seen in most viral infections. The clinical and imaging findings associated with viral CNS infection are often nonspecific, with microbiologic analysis of cerebrospinal fluid the most useful single test allowing for diagnosis of a specific viral infection. This review details the spectrum of viral CNS infections and uses case material from the archives of the American Institute for Radiologic Pathology, with a focus on the specific clinical characteristics and magnetic resonance imaging features seen in these infections. Where possible, the imaging features that allow distinction of these infections from other CNS inflammatory conditions are highlighted.
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PMID:Viral and Prion Infections of the Central Nervous System: Radiologic-Pathologic Correlation: From the Radiologic Pathology Archives. 2807 19