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Biomedical subjects

N Yuki

Publications and source records attributed to N Yuki.

At least 199 records · Page 11Linked to original sources
PubMed1996

The F wave disappears due to impaired excitability of motor neurons or proximal axons in inflammatory demyelinating neuropathies.

OBJECTIVES: Investigation of pathophysiology of F wave disappearance in demyelinating neuropathies. METHODS: The peripheral motor nerve conduction was studied by motor evoked potential (MEP) on transcranial magnetic stimulation as well as conventional nerve conduction studies before and after the treatment in 26 patients with inflammatory demyelinating neuropathies. In addition, serum antiganglioside antibodies in the acute or active stage were examined. RESULTS: The F wave was abolished in 10 patients. Seven of the 10 patients showed motor evoked potentials (MEPs) on transcranial magnetic stimulation that ranged from 1-4 mV. In six of them the F wave reappeared in the recovery stage, but the MEP size did not change. This may be caused by humoral factors, because the F wave reappeared immediately after plasma exchange or intravenous immunoglobulin treatment. A correlation of F wave disappearance with the presence of serum antiganglioside antibodies was found. CONCLUSIONS: The major pathophysiology of F wave disappearance in demyelinating neuropathies is impairment of motor neuron excitability or prolonged refractoriness of the most proximal axon for backfiring. The conventional interpretation that absent F waves suggest a conduction block at the proximal site is often inadequate.

Acute Disease↗
PubMed1996

Tryptophan-immobilized column adsorbs immunoglobulin G anti-GQ1b antibody from Fisher's syndrome: A new approach to treatment.

Sera from patients with Fisher's syndrome in the acute phase contain immunoglobulin (Ig)G anti-GQ1b ganglioside antibody. Removal of the autoantibody should lead to earlier recovery with less residual neurologic involvement. A tryptophan- or phenylalanin-immobilized polyvinyl alcohol gel column (IM-TR 350 or IM-PH 350) semiselectively adsorbs such autoantibodies as rheumatoid factor, anti-DNA antibody, or anti-acetylcholine receptor antibody. A batchwise adsorption test showed that an IM-TR gel adsorbed a larger amount of the IgG anti-GQ1b antibody than did an IM-PH column. Several patients with Fisher's syndrome therefore were given immunoadsorbent therapy using the IM-TR column without adverse reactions. An ex vivo plasma perfusion study done with the IM-TR column confirmed that it effectively adsorbs the IgG anti-GQ1b antibody. Results of adsorption tests done with various amino acid-immobilized gels suggest that both the hydrophobic force of the side chain and the anionic charge of the carboxylic acid in tryptophan are important in the adsorption of the autoantibody by the IM-TR gel. Immunoadsorption using the IM-TR column, which does not need replacement fluids, offers an alternative type of plasmapheresis for Fisher's syndrome.

Adolescent↗
PubMed1996

[Removal ability of IgG anti-GQ1b antibody in immunoadsorption therapy for Fisher syndrome--comparison of the removal ability between tryptophane column and phenylalanine column].

Anti-GQ1b antibody seems to be a pathogenetic factor in the development of Fisher syndrome (FS). Although several patients received immunoadsorption therapy (IAT), whether it can remove the autoantibody has not yet been clarified. We treated two patients with FS by IAT using tryptophane column (TR-C) and phenylalanine column (PH-C) (TR-C; 9 times altogether in 2 patients, PH-C: twice altogether in 2 patients), and compared the removal ability of IgG anti-GQ1b antibody and immunoglobulin between TR-C and PH-C. TR-C removed the IgG anti-GQ1b antibodies, IgG, IgA and IgM more than PH-C did. TR-C removed the IgG anti-GQ1b antibody more selectively than non-specific immunoglobulin. In practicing IAT on FS, the use of TR-C rather than PH-C is recommended in view of the removal ability of the autoantibody.

Adult↗
PubMed1996

[Immunoadsorption therapy for Fisher's syndrome: analysis of the recovery process of external ophthalmoplegia and the removal ability of anti-GQ1b antibodies].

The beneficial effect of plasma exchange, plasmapheresis or immunoadsorption therapy on Fisher's syndrome, suggested previously, has not been proved since no controlled studies have been conducted. In order to assess the effect of any treatment on Fisher's syndrome, simple and reasonable grading scales for evaluating the major neurological signs are needed. We tried immunoadsorption therapy in four patients with Fisher's syndrome, whose sera had anti-GQ1b antibodies. The clinical course was observed, with assessment of the severity of the major neurological signs based on grading scores; ranging from 0 to 30 for external ophthalmoplegia, from 0 to 10 for ataxia, and from 0 to 16 for areflexia. Tryptophan- or phenylalanine-linked polyvinyl alcohol gel column (TR-350, PH-350) was used as an adsorbent. In a patient who had IgG anti-GQ1b antibody and another patient who had both IgG and IgM anti-GQ1b antibodies, we compared the effectiveness of TR-350 and PH-350 to remove the anti-GQ1b antibody during the therapy. Two patients underwent immunoadsorption therapy at the height of clinical manifestations: in one patient, the therapy was discontinued because of critical hypotension and arrhythmia; the other was given only three sessions of therapy. The other two patients received six or seven sessions during the early recovering stage. All patients recovered without major neurological sequelae. Since ataxia was improved earlier than external ophthalmoplegia, the duration of hospitalization and the time of return to social life depended upon the recovery of external ophthalmoplegia. Analysis of the time course of external ophthalmoplegia score indicated that the improving period and the 50%-recovery day came earlier in the patients who were given a sufficient number of sessions than those who received an insufficient number of sessions. The treatment with TR-350 reduced the IgG anti-GQ1b antibody titer more than that with PH-350, but reduced the IgM anti-GQ1b antibody titer similarly. Immunoadsorption therapy using TR-350 has a probable beneficial effect on Fisher's syndrome even though it is carried out after the height of illness. The evaluation method for the severity of external ophthalmoplegia that we used in the present study is useful for assessing the effect of therapy on Fisher's syndrome.

Adult↗
PubMed1996

Possible mechanism of intravenous immunoglobulin treatment on anti-GM1 antibody-mediated neuropathies.

Anti-GM1 antibody may function in disease development in some patients with Guillain-Barré syndrome, chronic inflammatory demyelinating polyradiculoneuropathy and multifocal motor neuropathy. Intravenous immunoglobulin (IVIg) therapy is effective in these neuropathies, but the mechanism by which IVIg acts is not clear. To test whether it has anti-idiotypic activity on anti-GM1 antibody, we investigated whether IVIg inhibits the binding of cholera toxin to GM1. It inhibited the reaction between cholera toxin and GM1 mediated by F(ab')2 fragments of IgG. Treatment with sialidase did not inhibit the binding of cholera toxin to GM1, whereas denaturation with guanidine did. This suggests that the GM1 epitope in IVIg has peptide and not carbohydrate structures. The variable region of IVIg may bind to anti-GM1 antibody, as well as to cholera toxin, thereby neutralizing the pathogenic effects of the autoantibody.

Antigen-Antibody Reactions↗
PubMed1996

[Fisher's syndrome with profound hypotension].

A case of Fisher's syndrome was described in which profound hypotension was encountered. A 70-year-old previously healthy female developed diplopia and unsteady gait following an upper respiratory infection. On admission, her blood pressure was 140/60 mmHg. Adduction of the left eye and elevation of the right eye were limited. Other cranial nerve functions and muscle strength were intact. She had gait ataxia with negative Romberg sign. Tendon reflexes were hypoactive. The cerebrospinal fluid, electrocardiography, and cranial MR imaging were unremarkable. Her serum had a high titer of IgG anti-body. After admission she developed bilateral internuclear ophthalmoplegia and severe gait ataxia. During double filtration plasmapheresis, her systolic pressure fell down to 60 mmHg. To maintain her systolic pressure between 90 and 120-mmHg supine, infusion of lactated Ringer solution (3,000-3,500 ml/day), dopamine hydrochloride (10-12 micrograms/kg/min), and norepinephrine (50-90 ng/kg/min) was needed for 3 weeks. There was no evidence of denervation supersensitivity. Echocardiography demonstrated normal cardiac output, suggesting that decreased vascular resistance was responsible for her hypotension. In Guillain-Barré syndrome, cardiovascular dysautonomia is frequently encountered and is occasionally related to sudden death. In contrast, Fisher's syndrome with cardiovascular dysautonomia has been rarely reported. Cardiovascular functions should be monitored in every patient with Fisher's syndrome.

Aged↗
PubMed1995

Clinical characteristics and antibody profiles of chronic hepatitis C patients: relation to hepatitis C virus genotypes.

Genotyping of 179 consecutive Japanese chronic hepatitis C patients was carried out based on the variation in the hepatitis C virus (HCV) core gene. The results were correlated with clinical features and antibody responses toward specific HCV proteins deduced from the nucleotide sequence of genotype I/1a. Genotypes II/1b, III/2a, and IV/2b were identified in 138 (77%), 24 (13%), and 12 (7%) patients, respectively. Five patients had double infections. Genotype dependence was observed only for antibody response toward the NS4 (5-1-1) protein, which was infrequent in genotype III/2a patients (33%) compared with genotype II/1b (81%; P < 0.01) and genotype IV/2b (75%; P < 0.05). Following interferon-alpha therapy, sustained amniotransferase normalisation was achieved by 89% (eight of nine) patients without antibody to the 5-1-1 protein and 33% (17 of 51) with it (P < 0.01). These findings indicate that absence of antibody response to the 5-1-1 protein is frequent in genotype III/2a HCV carriers and may serve to predict responses to interferon therapy.

Adult↗
PubMed1995

Long-term follow-up of hepatitis B virus and hepatitis C virus replicative levels in chronic hepatitis patients coinfected with both viruses.

Dual infection with hepatitis B and C viruses is often encountered in endemic areas of both viruses. However, understanding of the clinical and virological implications is limited. The aim of this study was to investigate the role of each virus in liver injury and the interaction between the two viruses in dual infection with hepatitis B and C viruses. Three patients who had chronic infection with both hepatitis B and C viruses were examined, and a longitudinal study of both serum hepatitis B virus DNA and hepatitis C virus RNA levels over 4 years was undertaken. The results were correlated with serum alanine aminotransferase levels. Serum alanine aminotransferase values showed a relationship with hepatitis B virus replicative levels, but not with hepatitis C virus replicative levels in all 3 patients. Serial changes of replicative levels of both viruses were studied, and it was found that hepatitis C virus replicative levels were enhanced after the decline of hepatitis B virus replication in 1 of the 3 patients. In the remaining 2 patients, a transient rise of hepatitis C virus replicative levels in association with a decrease of hepatitis B virus replication was also observed during part of the follow-up period. These findings indicate that hepatitis B virus may play a dominant etiological role in liver injury, and that a suppressive action between hepatitis B and C viruses may occur in dual infection with both viruses.

Adult↗
PubMed1995

Ganglioside-like epitopes of lipopolysaccharides from Campylobacter jejuni (PEN 19) in three isolates from patients with Guillain-Barré syndrome.

Sera from patients with Guillain-Barré syndrome (GBS) frequently have anti-GM1 antibody. We earlier showed that an lipopolysaccharides (LPS) from Campylobacter jejuni (PEN 19) isolated from a GBS patient has a GM1 ganglioside-like structure. Aspinall et al. (Biochemistry, 61 (1994) 335-337) reported that OH 4382 has an LPS that bears a CD3 ganglioside-like structure and that OH 4384 has an LPS that bears a GT1a-like structure; both strains were isolated from patients with GBS. They also suggested a GM1-like structure is present in the LPSs from OH 4384, but failed to show the presence in the LPSs from OH 4382. To clarify the pathogenesis of GBS after infection by C. jejuni (PEN 19), we investigated the carbohydrate structures of the three strains by thin-layer chromatography immunostaining with cholera toxin and monoclonal anti-ganglioside antibodies. We found that both OH 4382 and OH 4384 have an LPS with the GM1 epitope as well as one with the GT1a or GD3 epitope.

Antibodies, Bacterial↗
PubMed1995

Ganglioside characterization of a cell line displaying motor neuron-like phenotype: GM2 as a possible major ganglioside in motor neurons.

We have examined ganglioside compositions and the presence of sulfated glucuronyl glycolipids of immortalized motor neuron-like cell lines, neuroblastoma-spinal cord (NSC) hybrid cell lines established by fusing mouse neuroblastoma N18TG2 with motor neuron-enriched embryonic spinal cord cells. Among NSC cell lines, only NSC-34 aggregates acetylcholine receptors on co-cultured myotube and expresses a receptor for S-laminin, a neuromuscular junction specific basal lamina protein. GM2, which is only a minor ganglioside component of CNS, was the major component in NSC-34 occupying almost 75% of total gangliosides, whereas GD1a and GM3 were major species in the parental N18TG2, which had only 8.5% GM2. These results indicated that NSC lines have unique ganglioside pattern that is distinctive from other nervous tissues, and this pattern, especially that of NSC-34 cells, might reflect the characteristics of mouse spinal motor neuron gangliosides. Sulfated glucuronyl paragloboside was demonstrated to be present in N18TG2, however, it could not be detected in either of NSC cell lines. Even though the pathogenesis of amyotrophic lateral sclerosis remains unknown, autoimmunological participation has been suggested. Because high-titered antibody against GM2 has been observed in a patient with amyotrophic lateral sclerosis-like disease, GM2 which is possibly expressed on the surface of motor neurons might serve as a potential target antigen in this disorder.

Animals↗
PubMed1995

Successful plasmapheresis in Bickerstaff's brain stem encephalitis associated with anti-GQ1b antibody.

Patients with Guillain-Barré syndrome (GBS) and Fisher's syndrome (FS) benefit from plasmapheresis. Specific treatments, however, have yet to be established for Bickerstaff's brain stem encephalitis (BBE). We showed earlier that sera from BBE patients, as well as from patients with FS and GBS with ophthalmoplegia, have autoantibody to GQ1b ganglioside in the acute phase of the disease. We report 2 BBE patients who had high IgG anti-GQ1b antibody titers and were treated successfully with plasmapheresis.

Adult↗
PubMed1995

Subclass of IgG antibody to GM1 epitope-bearing lipopolysaccharide of Campylobacter jejuni in patients with Guillain-Barré syndrome.

Sera of patients who develop Guillain-Barré syndrome (GBS) subsequent to Campylobacter jejuni enteritis frequently have IgG anti-GM1 antibody. Lipopolysaccharide (LPS) of C. jejuni isolated from a GBS patient has a GM1 ganglioside-like structure. IgG subclass distribution of the anti-GM1 antibody in GBS patients is mainly restricted to IgG1 and IgG3. Since IgG antibodies to bacterial polysaccharide generally are restricted to IgG2 subclass, some investigators have assumed that either the general rules for immune response to LPS are broken in the patients or an alternative antigen has yet to be identified. To clarify whether the LPS participates in the production of the anti-GM1 antibody, we investigated the subclass of IgG antibody to the LPS that bears GM1-like structure. The subclasses of IgG antibody to the LPS were restricted predominantly to IgG1 and IgG3. The GM1 epitope-bearing LPS may function in the production of the anti-GM1 antibody in patients with GBS subsequent to C. jejuni infection.

Campylobacter jejuni↗
PubMed1995

Pretreatment viral load and response to prolonged interferon-alpha course for chronic hepatitis C.

BACKGROUND/AIMS: We investigated the clinical benefit of long-term interferon therapy in chronic hepatitis C in relation to the pretreatment viral load and genotypes. METHODS: Chronic hepatitis C patients were randomly assigned to receive 28-week (n = 45) or 52-week (n = 43) courses of interferon-alpha. The responses were correlated with pretreatment viremic levels assessed by a branched DNA assay and genotypes. RESULTS: After the 28-week interferon-alpha course, sustained aminotransferase normalization showed correlation with a lower initial viral load. The normalization was achieved by 78% (7/9) of the low viremic (branched DNA-negative) patients, but only 22% (8/36) of the highly viremic (branched DNA-positive) patients (p < 0.01). Treatment with the 52-week interferon-alpha course increased the incidence of a sustained response in highly viremic patients and led to a decrease in relapse after therapy withdrawal (p < 0.05). Thus, 75% (6/8) of the low viremic patients and 49% (17/35) of the highly viremic patients showed a sustained response. The data further showed that frequent sustained responses in patients with genotypes III and IV were associated with a low initial viral load. CONCLUSIONS: These findings suggest that although the pretreatment viral load is an important virological factor for predicting responses to interferon in chronic hepatitis C, relapse in highly viremic patients may be prevented by long-term therapy.

Adult↗
PubMed1995

Fisher syndrome after Campylobacter jejuni enteritis: human leukocyte antigen and the bacterial serotype.

We describe two children who had Fisher syndrome subsequent to Campylobacter jejuni enteritis. The C. jejuni isolates from both patients, who lived in different areas, belonged to PEN 2: LIO 4. One patient had the following human leukocyte antigens (HLAs): HLA-A24, 33; B44, 52; DQ1; and DR2, 6 antigens. Another had the HLA-A24, 33; B44, 54; Cw1; DQ1, 4; and DR4, 6. An effort should be made to isolate C. jejuni from patients with Fisher syndrome and to perform HLA typing so that the pathogenesis of this syndrome can be clarified.

Adolescent↗