Clinical epidemiology and analysis of pathomechanisms of optic-spinal form of multiple sclerosis

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We studied clinical features and pathomechanisms of multiple sclerosis (MS) in Japan, especially optic-spinal form of MS (OSMS). (l)Eighty six cases of MS whose onset of disease were during 1970-1998 were clinically classified. Frequency of cases of MS with acute transverse myelitis (ATM) decreased in 1980s and 1990s compared with 1970s. In contrast, OSMS without ATM and conventinal MS increased in 1 980s. Changes of environmental factors might have caused these changes of clinical picture of MS in Japan. Brainstem and cerebellar symptoms and signs and MRI findings were analyzed in 66 consecutive cases of MS, and 65% had those symptoms and signs. Cerebellarsigns were seen in 30%. Moreover, cerebellar lesions on MRI were seen in only 6.4%, which was significantly lower than the figures in Western countries (50-90%). (2)4-aminopyridine (4-AP) relieves conductionlock in demyelinated nerves by blocking K channels. 4-AP was administered intravenously and motor evoked potentials (MEP) were recorded before and after 4-AP therapy. After 4-AP therapy, MEP amplitudes increased significantly and mean consecutive difference of MEP latency decreased significantly. 4-AP probably caused coordinated contraction of more muscle fibers. (3) Parvovirus 819 (B19) infection is associated with autoimmunity. B19 antibodies in sera and cerebrospinal fluid (CSF) and B19 DNA in CSF were studied in 46 MS patients. Frequency of B19 lgG in MS (65%) was significantly higher than that in controls (40%), but serum 819 lgM and B19 DNA in CSF were consistently negative in excerbation of MS.