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Biomedical subjects

N Yuki

Publications and source records attributed to N Yuki.

At least 235 records · Page 13Linked to original sources
PubMed1994

IgG and IgM core antibodies and viral replication in hepatitis C virus carriers.

We studied IgG and IgM antibodies to hepatitis C virus core protein (anti-HCVcore) in relation to serum virus RNA levels in 71 hepatitis C virus carriers. Viremic levels ranged from 10(4)-10(9) copies/ml and were high in 34 chronic active hepatitis patients compared with 17 asymptomatic carriers and 20 cases of chronic persistent hepatitis (p < 0.01). IgG anti-HCVcore was found in 67/71 (94%), but four asymptomatic carriers with low levels of viremia (10(4)-10(5.5) copies/ml) tested negative. IgM anti-HCVcore was found in patients with high levels of viremia (10(8)-10(9) copies/ml), and one (6%) asymptomatic carrier and nine (26%) chronic active hepatitis patients tested positive. In chronic hepatitis patients, viremic levels were significantly higher in cases positive for IgM anti-HCVcore than in negative ones (p < 0.01). However, no correlation was found between the occurrence of IgM anti-HCVcore and serum aminotransferase levels or the histologic activity index. These findings suggest that although IgG anti-HCVcore is sensitive, low viremic patients can escape this screening, and that the IgM anti-HCVcore is induced in association with high levels of virus replication.

Adult↗
PubMed1994

Hepatitis C virus antibodies and virus replication in asymptomatic blood donors.

We assessed hepatitis C virus (HCV) infection in 99 asymptomatic blood donors positive using a first-generation HCV antibody assay. When tested with second-generation assays, 86 (87%) donors were reactive (group 1), 2 (2%) were indeterminate (group 2), and 11 (11%) were non-reactive (group 3). Viraemia was revealed by polymerase chain reaction in all group 1 cases. The 2 group 2 cases and 6 (55%) group 3 cases were also viraemic. Viraemia was confirmed by a branched DNA assay in the 2 group 2 cases and 4 (36%) group 3 cases. Serum HCV RNA levels were further studied using a competitive reverse transcription-polymerase chain reaction assay. All cases in groups 2 and 3 were low viraemic (range 10(4)-10(5.5) copies/ml) compared with the 9 group 1 cases examined (range 10(7)-10(9) copies/ml). No correlation was evident between viraemic levels and antibody cut-off index in the first-generation assay. These findings indicate the possibility that low levels of viraemia can occur in individuals non-reactive in second-generation HCV antibody assays.

Adult↗
PubMed1994

Immunological properties and ganglioside recognitions by Campylobacter jejuni-enterotoxin and cholera toxin.

The immunological properties of Campylobacter jejuni enterotoxin (CJT) and cholera toxin (CT) were compared by enzyme-linked immunosorbent assay (ELISA) and Western blotting analysis with antiserum against each toxin. Antibody against CJT recognized the 68, 54 and 43 kDa polypeptides of CJT and the 11 kDa subunit of CT, whereas antibody against CT recognized the 68 and 54 kDa polypeptides of CJT and 11 kDa subunit of CT. The immunological reactions between the heterogeneous combinations of toxins and the antibodies were weaker than those between the homogenous systems. Thus, different antigenicity was found in CJT and CT at the subunit level, although they possessed cross-reactive epitope(s). The binding of CJT and CT to gangliosides was also examined. CJT and CT bound to GM1 ganglioside preferentially than to other ganglioside species. However, CJT did not bind to GD1b in spite of the fact that CT preferred GD1b. This suggests that both toxins recognize different receptors on the surface of the target cell. This study is the first demonstration of the different properties between CJT and CT in immunological character and ganglioside recognition.

Antibodies, Bacterial↗
PubMed1994

Penner's serotype 4 of Campylobacter jejuni has a lipopolysaccharide that bears a GM1 ganglioside epitope as well as one that bears a GD1 a epitope.

The carbohydrate structures of lipopolysaccharides (LPSs) of Campylobacter jejuni strains belonging to Penner's serotypes (PEN) 1, 2, 4, 19, 23, and 36 were studied by thin-layer chromatography and immunostaining with several monoclonal antiganglioside antibodies. Anti-GM1 and anti-GD1a antibodies reacted with the LPSs of PEN 1, 4, and 19. Aspinall et al. (G. O. Aspinall, A. G. McDonald, T. S. Raju, H. Pang, A. P. Moran, and J. L. Penner. Eur. J. Biochem. 213:1017-1027, 1993) recently reported that the LPS of PEN 4 has a GD1a ganglioside-like structure rather than a GM1-like structure. We found that the LPS fraction of C. jejuni (PEN 4) has an LPS that bears a GM1 epitope as well as an LPS that bears a GD1a epitope.

Antibodies, Monoclonal↗
PubMed1994

Hepatitis C virus replication and antibody responses toward specific hepatitis C virus proteins.

We assessed the correlation between hepatitis C virus replication and antibody responses toward hepatitis C virus core (C22-3), NS3 (C33C), NS4 (5-1-1 and C100-3) and NS5 proteins in 59 virus carriers. The concentration of serum hepatitis C virus RNA was determined by a competitive reverse transcription-polymerase chain reaction assay. All 50 patients with high viremic levels of > or = 10(6) copies/mL had antibodies to C22-3 and C33C. Antibodies to 5-1-1, C100-3 and NS5 proteins were detected less frequently (p < 0.01) in 72% (36 of 50), 78% (39 of 50) and 84% (32 of 38) of such patients, respectively. As for the nine patients with low viremic levels of < 10(6) copies/mL, antibodies to C22-3, C33C, 5-1-1 and NS5 proteins were detected in only one patient (11%), which was significantly less than the frequency for highly viremic patients (p < 0.01). Antibody to C100-3 was also found less frequently in only four patients (44%) (p < 0.05). Thus, only four (44%) of the nine low viremic patients tested positive for any antibody compared with all 50 highly viremic patients (p < 0.01). These results indicate that highly viremic carriers can be detected by the presence of hepatitis C virus antibodies, but a considerable proportion of low viremic carriers may not show any serological evidence of hepatitis C virus infection.

Adult↗
PubMed1994

[Acute relapsing sensory-dominant polyneuropathy associated with anti-GQ1b antibody and autoimmune hepatitis].

A 43-year-old male with 2 episodes of sensory impairments in four extremities and liver dysfunction, developed an acute exacerbation of both sensory impairments and liver dysfunction after administration of interferon-alpha. On admission, neurological examination revealed a mild distal weakness of four extremities, moderate impairment of superficial sensation in hands and severe impairment of deep sensation and areflexia in all extremities. Routine laboratory tests were normal except for a mild liver dysfunction. His serum was positive for antinuclear antibody, but negative for anti-DNA antibody and LE-test. Since he was seropositive for hepatitis B (HB) c antibody but seronegative for HBs antigen and antibody, HBe antigen and antibody, he was considered to be a seroconverted carrier of HB virus. Liver biopsy revealed chronic active hepatitis with marked lymphocytic infiltration. CSF examinations were within normal limits. Sensory conduction studies of median and sural nerves showed no response, but motor conduction studies of median and peroneal nerves were within normal limits. Light and electron microscopic examination of biopsied sural nerve disclosed a moderate decrease in large myelinated fibers, but not in either small myelinated or unmyelinated fibers. Thin-layer chromatography with immunostaining showed the presence of anti-GQ1b antibody in his serum. The anti-GQ1b antibody did not react with GT1a. Oral administration of prednisolone alleviated liver dysfunction, muscle weakness and superficial sensory impairment of four extremities, but not in deep sensation.

Acute Disease↗
PubMed1994

[Acute relapsing ataxic polyradiculoneuritis following respiratory tract infections].

We report a patient with a relapsing form of acute ataxic polyradiculoneuritis. The patient developed marked sensory ataxia with mild limb weakness following a respiratory tract infection. Five similar relapses occurred over 18 years. The symptoms reached their maximum in 2 weeks, followed by subsequent gradual improvement over 1-2 months. Sural nerve biopsy showed mild loss of large myelinated fibers.

Acute Disease↗
PubMed1994

[Atypical Guillain-Barré syndrome associated with ophthalmoplegia and visual impairment following herpes simplex virus type 1 infection].

Two weeks after a flu-like illness, a 59-year-old woman developed double vision, muscle weakness and sensory discomfort in the proximal portions of her limbs. On admission, there was complete external ophthalmoplegia with bilateral ptosis. The pupils were dilated and did not react to light. Swallowing and elevation of the soft palate were also limited. There was severe muscle weakness in all limbs. Deep tendon reflexes were absent. Superficial and deep sensations were impaired in the proximal portions of the extremities. Neuro-ophthalmological examinations revealed an acquired color disorder with no scotoma and normal discs. P100 latencies of flashed visual evoked potentials were prolonged on day 41, and returned to normal on day 87. Herpes simplex virus type 1 (HSV-1) infection was confirmed by isolation of the virus from her sputum and the detection of anti-HSV-1 antibody in the acute phase serum.

Female↗
PubMed1994

[A patient with Guillain-Barré syndrome in association with Campylobacter jejuni enteritis (PEN19:LIO7) in a patient with HLA-B52 antigen].

We report a 15-year-old boy with Guillain-Barré syndrome (GBS) in association with Campylobacter jejuni enteritis. A neurologic examination revealed distal-dominant weakness and areflexia. Compound muscle action potentials were markedly reduced in amplitude, but the decrease in motor conduction velocities was slight. C. jejuni was isolated from his stool culture and the serotype belonged to PEN19:LIO7. Thin-layer chromatography-immunostaining showed that his serum IgG reacted strongly with GM1 and weakly with GD1b. The patient had HLA-B52 antigen, whose epitope is very similar to that of B35 antigen.

Adolescent↗
PubMed1994

[Guillain-Barré syndrome].

Sera from patients with Guillain-Barré syndrome (GBS) following Campylobacter jejuni infection have autoantibody to GM1 ganglioside in the acute phase of the illness. There is a strong association between GBS and Penner's serotype 19 (PEN 19) of C. jejuni. The terminal structure of the bacterial lipopolysaccharide is identical to the terminal tetrasaccharide of GM1 ganglioside. Anti-GM1 antibody inhibits motoneuron excitability. Molecular mimicry between infectious agents and nerve tissue components may function in the development of GBS.

Campylobacter Infections↗
PubMed1994

[Guillain-Barré syndrome associated with anti-GQ1b antibody--nosological relationship between Fisher's syndrome and Guillain-Barré syndrome].

A 15-year-old man developed diplopia, ataxic gait and bulbar palsy. Two days after the onset of neurological symptoms, neurological examination revealed external ophthalmoplegia, cerebellar ataxia, and areflexia. Muscle weakness in the areas innervated by cranial nerves and in the four limbs, and glove and stocking type sensory impairment were also observed. On the 13th hospital day, CSF protein was elevated with normal cellularity. Serum IgM anti-GQ1b antibody was increased, which decreased concurrently with the clinical improvement. Recent studies have revealed the frequent presence of serum anti-GQ1b antibody in Fisher's syndrome. Therefore, this patient showed Fisher's syndrome at the beginning, then evolved to Guillain-Barré syndrome associated with anti-GQ1b antibody, which would support close association between Fisher's syndrome and Guillain-Barré syndrome.

Adolescent↗
PubMed1994

[Bickerstaff's brainstem encephalitis associated with cytomegalovirus infection].

A 17-year-old girl was admitted to our hospital because of drowsiness, diplopia and gait difficulty. She had been well until ten days before admission when fever, drowsiness, headache and general fatigue developed. On admission, there were drowsiness, ophthalmoplegia, ataxia and hyporeflexia. CSF cells and anti-CMV antibody titers increased. CMV-DNA was detected in the CSF by the polymerase chain reaction (PCR). Serum anti-GQ1b antibody was positive. During recovery, forced laughing temporarily appeared. The neurological symptoms disappeared completely. CSF anti-CMV antibody titers became normalized and CSF CMV-DNA-PCR became negative. This is the first case report of Bickerstaff's brainstem encephalitis associated with CMV infection.

Adolescent↗
PubMed1994

Serum hepatitis C virus RNA levels and liver injury in volunteer blood donors.

OBJECTIVES: Liver histology in volunteer blood donors positive for serum hepatitis C virus RNA was investigated in relation to hepatitis C virus viremia levels. METHODS: Twenty-one volunteer blood donors positive for serum hepatitis C virus RNA by polymerase chain reaction were monitored for at least 1 yr by monthly routine liver function tests and underwent liver biopsy. Liver histology findings were correlated with hepatitis C virus viremia levels assessed by a quantitative branched DNA assay. RESULTS: Liver histology showed the features of chronic hepatitis in 20 (95%) patients. Only one of the seven patients with persistently normal aminotransferase levels during follow-up had normal liver histology, and the others had chronic hepatitis. Sera obtained the same day of the liver biopsy were shown to contain hepatitis C virus RNA of 10(5.7)-10(7.6) equivalent/ml (median 10(6.7)). The total histological activity index score (median 2, range 0-15) and the scores of portal inflammation (median 1, range 0-3), lobular inflammation (median 1, range 0-4) and piecemeal necrosis (median 0, range 0-5) correlated with viremia levels (r = 0.64, p < 0.01; r = 0.60, p < 0.01; r = 0.48, p < 0.05; and r = 0.49, p < 0.05, respectively). CONCLUSIONS: These findings suggest that chronic hepatitis is frequently caused by hepatitis C virus infection irrespective of the serum aminotransferase levels, and high level hepatitis C virus replication is a contributory cause for liver injury in volunteer blood donor populations.

Alanine Transaminase↗
PubMed1994

[Probable Bickerstaff's brainstem encephalitis associated with anti-GQ1b antibody].

We presented a case of probable Bickerstaff's brainstem encephalitis. A 39-year-old woman developed easy falling, progressive consciousness disturbance, total ophthalmoplegia, and bilateral pyramida tract sign. In serum anti-ganglioside antibody assay using enzyme-linked immunosorbent assay, high anti-GQ1b antibody was found. Electroencephalography was dominated by alpha activity, superimposed with occasional theta wave bursts. Brain MRI showed abnormal signal hyperintensities in the tegmentum of the midbrain to the upper pons on T2 weighted images and swelling of the midbrain and pons on T1 weighted images. Five days after the onset of the disease, she had respiratory arrest, which necessitated artificial ventilation for a few days. Then, she began to recover. However, she gained only partial recovery, leaving upward gaze palsy, right abducens nerve palsy, pseudbulbar palsy and quadriplegia.

Adult↗
PubMed1993

A bacterium lipopolysaccharide that elicits Guillain-Barré syndrome has a GM1 ganglioside-like structure.

There is a strong association between Guillain-Barré syndrome (GBS) and Penner's serotype 19 (PEN 19) of Campylobacter jejuni. Sera from patients with GBS after C. jejuni infection have autoantibodies to GM1 ganglioside in the acute phase of the illness. Our previous work has suggested that GBS results from an immune response to cross-reactive antigen between lipopolysaccharide (LPS) of the Gram-negative bacterium and membrane components of peripheral nerves. To clarify the pathogenesis of GBS, we have investigated whether GM1-oligosaccharide structure is present in the LPS of C. jejuni (PEN 19) that was isolated from a GBS patient. After extraction of the LPS, the LPS showing the binding activity of cholera toxin, that specifically recognizes the GM1-oligosaccharide was purified by a silica bead column chromatography. Gas-liquid chromatography-mass spectrometric analysis has shown that the purified LPS contained Gal, GalNAc, and NeuAc, which are sugar components of GM1 ganglioside. 1H NMR methods [Carr-Purcell-Meiboom-Gill (CPMG), total correlation spectroscopy (TOCSY), and nuclear Overhauser effect spectroscopy (NOESY)] have revealed that the oligosaccharide structure [Gal beta 1-3 GalNAc beta 1-4(NeuAc alpha 2-3)Gal beta] protrude from the LPS core. This terminal structure [Gal beta 1-3GalNAc beta 1-4(NeuAc alpha 2-3)Gal beta] is identical to the terminal tetrasaccharide of the GM1 ganglioside. This is the first study to demonstrate the existence of molecular mimicry between nerve tissue and the infectious agent that elicits GBS.

Adult↗
PubMed1993

Novel lacto-ganglio type gangliosides with GM2-epitope in bovine brain which react with IgM from a patient of the amyotrophic lateral sclerosis-like disorder.

A motor neuron disorder resembling that of amyotrophic lateral sclerosis was found in a patient who had received the intramuscular administration of a mixture of bovine brain gangliosides (Yuki, N., Sato, S., Miyatake, T., Sugiyama, K., Katagiri, T., and Sasaki, H. (1991) Lancet 337, 1109-1110). A very high titer of anti-GM2 IgM was detected in the patient's serum and the patient quickly recovered after plasmapheresis. The clinical course of the patient appeared to be different from amyotrophic lateral sclerosis and the anti-GM2 IgM was thought to be the culprit. The IgM reacted with GM2, GM1b-GalNAc, SPG(alpha 2-3)-GalNAc, and GD1a-GalNAc, but not with GA2 or GD2, meaning that the epitope recognized by the IgM was the GM2-like terminal structure, GalNAc beta 1-4(Neu-Ac alpha 2-3)Gal beta 1-. In this study, we found two novel GM2-epitope containing gangliosides, X1 and X2, in bovine brain gangliosides by TLC immunostaining using the patient's IgM. They were characterized as unique lacto-ganglio type gangliosides containing the following branching structures. [formula: see text] Their unusual structures may be immunogenic to humans to induce anti-GM2 antibody.

Aged↗
PubMed1993

Anti-B-series ganglioside-recognizing autoantibodies in an acute sensory neuropathy patient cause cell death of rat dorsal root ganglion neurons.

To examine the cytotoxicity of a patient's serum with an acute relapsing sensory neuropathy syndrome, dorsal root ganglion neurons from young adult rats were cultured in the presence of the patient's serum which had an extremely higher-titer monoclonal IgM antibody recognizing B-series gangliosides, GD2, GD1b, GT1b and GQ1b. By the addition of the inactivated patient's serum, the relatively larger cells died after undergoing of metamorphosis during several hours of culture, whilst the smaller cells survived. The IgM fraction isolated from the patient's serum showed similar cytotoxicity towards the neurons as the inactivated whole serum. No cytotoxicity was observed with the IgM fraction-containing medium after it had been absorbed with ganglioside GD1b. The results suggested that the anti-B-series ganglioside-directed antibody is the causal agent for the human neurologic disease.

Acute Disease↗