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Minoru Shibata

Publications and source records attributed to Minoru Shibata.

At least 19 recordsLinked to original sources
PubMed2006

A neurosphere-derived factor, cystatin C, supports differentiation of ES cells into neural stem cells.

Although embryonic stem (ES) cells are capable of unlimited proliferation and pluripotent differentiation, effective preparation of neural stem cells from ES cells are not achieved. Here, we have directly generated under the coculture with dissociated primary neurosphere cells in serum-free medium and the same effect was observed when ES cells were cultured with conditioned medium of primary neurosphere culture (CMPNC). ES-neural stem cells (NSCs) could proliferate for more than seven times and differentiate into neurons, astrocytes, and oligodendrocytes in vitro and in vivo. The responsible molecule in CMPNC was confirmed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, which turned out to be cystatin C. Purified cystatin C in place of the CMPNC could generate ES-NSCs efficiently with self-renewal and multidifferentiation potentials. These results reveal the validity of cystatin C for generating NSCs from ES cells.

Animals↗
PubMed2006

Sprouting of sensory neurons in dorsal root ganglia after transection of peripheral nerves.

Morphological reaction of sensory neurons of dorsal root ganglia after peripheral nerve transection was investigated by a nerve tracing method using E. coli lacZ (beta-galactosidase) gene recombinant adenovirus. The sciatic nerve of the rat was transected and inoculated with the gene recombinant adenovirus from the cutting end of nerve fibers. The fixation was accomplished from one to six weeks after inoculation. A whole mount specimen was observed after the reaction in a X-galactocidase substrate. Newly formed sprouting processes of dorsal root ganglion (DRG) cells appeared, all of them sprouting from the primary segment of DRG cells. Developed branches were morphologically categorized in to two types: one was the "linear type" which showed diverged branches running straightly along the major axis of the DRG; the other was the "winding type" which exhibited a random running pattern to the original axons and wound and extended in all directions in dorsal root ganglia with many branches. Many of this type encircled other cell bodies and formed a ring-like structure. There was no difference in the size of cell bodies in either type or between the ring-like structure forming the cells and those cells encircled by them.

Adenoviridae↗
PubMed2005

Erythrocyte ribavirin concentration for assessing hemoglobin reduction in interferon and ribavirin combination therapy.

BACKGROUND: Ribavirin-induced hemolytic anemia is one of the important adverse effects for the premature cessation of interferon and ribavirin combination therapy for hepatitis C virus clearance. To elucidate the mechanism of this matter, we examined the effects of plasma and erythrocyte ribavirin concentration on hemoglobin (Hb) reduction to assess hemolytic anemia in this combination therapy. METHOD: Nineteen patients, treated with the interferon alpha-2b and ribavirin combination therapy, were included. Plasma and erythrocyte ribavirin concentrations were monitored for the first 28 days of the combination therapy, in relation to changes in hematological parameters, Hb and hematocrit values. The initial dose of ribavirin was 11.5+/-1.5mg/kg/day. RESULTS: Steady-state plasma and erythrocyte ribavirin concentrations were 8.9+/-2.6 and 1218+/-270muM, respectively. Significant correlation was observed between erythrocyte ribavirin and Hb reduction (r=0.360, p<0.05), but not between plasma ribavirin and Hb reduction. The patients with higher levels of erythrocyte ribavirin (>/=1000muM) had greater Hb reduction compared to those with lower levels (<1000muM) (3.8+/-1.2g/dL versus 2.6+/-0.9g/dL, p<0.05). Nine cases out of 12 patients who developed anemia within the first 28 days of the combination therapy had higher levels of erythrocyte ribavirin (>/=1000muM). CONCLUSION: We confirmed that erythrocyte ribavirin was strongly associated with Hb reduction in interferon and ribavirin combination therapy.

Journal Article↗
PubMed2005

Diagnosing clinical subsets of autoimmune liver diseases based on a multivariable model.

BACKGROUND: Diagnosing autoimmune hepatitis (AIH), primary biliary cirrhosis (PBC), primary sclerosing cholangitis, and other autoimmune liver diseases remains an imperfect process. We need a more accurate, evidence-based diagnostic system. METHODS: We conducted a national survey and identified 988 cases of liver disease which did not satisfy the inclusion criteria for any liver disease of known etiology. We expected these cases to include autoimmune liver disease (AILD) and its variant forms. We selected 269 prototype cases for which histological re-evaluation of liver biopsy by independent expert hepatopathologists and the original diagnosis coincided. We did a multiple logistic regression analysis to determine explanatory variables that would distinguish cases of AIH and PBC from those of non-AIH and non-PBC, respectively. We constructed a multivariable diagnostic formula that gave AIH and PBC disease probabilities and validated it in a study of an additional 371 cases (validation group). RESULTS: Based on the results of the statistical analysis, we selected three laboratory tests and four histological features as independent variables correlated to the diagnosis of both AIH and PBC. For the validation group, assuming that the original diagnosis was correct, the sensitivity and specificity for AIH were 86.3% and 92.4%, respectively. For PBC the sensitivity and specificity were 82.5% and 63.7%, respectively. A detailed analysis of inconsistent cases showed that the diagnosis based on the formula had given the correct diagnosis, for either AIH or PBC, except for 5 cases (1.3%) in which disease probability was low for both. CONCLUSIONS: A seven-variable formula based on three laboratory tests and four histological features gives significant information for the diagnosis of AILD.

Algorithms↗
PubMed2005

[Case of primary biliary cirrhosis patient with anti-p97/VCP antibodies presenting a mild clinical course].

In this study, we present a case of mild PBC that had anti-p97/VCP. A 53-year-old woman had been suspected of having chronic liver disease since 1983. In 1998, she visited the clinic, complaining of struma and pruritus. Laboratory findings on the first visit showed elevated levels of alkaline phosphatase (ALP) 454 IU/l(110-360), gammaGTP 250IU/l(-45) and IgM 671mg/dl(35-220). A screening of anti-mitochondrial antibody test was positive at a 1:80 dilution. A liver biopsy specimen revealed PBC at Scheuer stage 1. Following a treatment of ursodeoxycolic acid (UDCA) 300mg/day for 6 months, AMA and IgM were reduced to 1:20 and 220mg/dl, respectively. However, she was found to have low titer of anti-p97/VCP antibodies, determined by immunoprecipitation of radiolabeled recombinant protein produced by in vitro translation and transcription of the full length p97 cDNA. She has continued to be clinically stable following administration of UDCA 300mg. A PBC patient with anti-p97/VCP antibody showed a milder clinical course, suggesting some beneficial role of this antibody.

Adenosine Triphosphatases↗
PubMed2004

Proximal nerve elongation vs nerve grafting in repairing segmental nerve defects in rabbits.

If segmental nerve defects could be repaired by elongating the proximal or distal segments, nerve grafting might be unnecessary. We elongated a 40-mm proximal segment of an injured median nerve, in the rabbit right forelimb, at a rate of 1 mm/day for 10 days in 10 rabbits and for 15 days in another 10. On the left forelimb of the same rabbits, a 10- for 15-mm segment of the median nerve was removed, and a 10- for 15-mm segment, respectively, of the tibial nerve was grafted in its place. Four months after the initial surgery, nerve conduction velocity (NCV), contractile strength of the flexor digitorum superficialis (FDS), axon count, and axon diameter did not differ significantly between the 10-mm groups but were better in the 15-mm grafted group. Elongating the proximal nerve segment may be an alternative to grafting in repairing segmental defects of less than 10 mm.

Analysis of Variance↗
PubMed2004

Distal nerve elongation vs nerve grafting in repairing segmental nerve defects in rabbits.

Segmental nerve defects have been repaired with nerve grafts. However, regenerating fibers must go through two coaptation sites, and donor site morbidities are inevitable. We elongated the distal nerve segment using a tissue expander and reconnected the nerve. We compared these results with those of nerve grafting. Nerve injury models were created in the median nerves of both forelimbs in 27 rabbits. The right nerve was repaired by elongation, and the left by tibial nerve grafting. The length of the elongation was the same as that of the graft in each animal. Eight rabbits had a 10-mm segment repaired, 9 had a 15-mm segment repaired, and 10 had a 20-mm segment repaired. Evaluated outcomes were nerve conduction velocity, contractile force of the flexor muscle, axons number, and fiber diameter. The elongated and grafted groups did not differ substantially on any outcome. Distal nerve elongation could be an alternative to nerve grafting for repairing large nerve defects.

Analysis of Variance↗
PubMed2004

Prevalence of antimitochondrial antibody in Japanese corporate workers in Kanagawa prefecture.

BACKGROUND: The prevalence of antimitochondrial antibody (AMA) in humans and its relationship to the development of primary biliary cirrhosis (PBC) are not well known. We have estimated the frequency of AMA in the general population, and studied its association with PBC. METHODS: We studies 1714 corporate workers (median age, 48 years; range, 30 to 59 years) who had an annual health check from 1998 to 1999 at Kawasaki Social Insurance Hospital in Japan. We used an indirect immunofluorescence method for screening serum AMA. We applied the prevalence of AMA-positive people in the study group to the general population in Japan. Then the inferred AMA-positive population was compared to the actual number of patients with PBC in statistics published by the Japanese Government. RESULTS: AMA was detected in 11 of 1714 people (0.64%; 95% confidence interval, 0.26% to 1.02%). All these 11 sera reacted with 2-oxoacid-dehydrogenase complex by immunoblotting. Of these 11 individuals, none had subjective symptoms, all had normal serum bilirubin levels, and 6 had abnormal liver function test results. Using published statistics for the Japanese population, we inferred that there were approximately 336,472 AMA-positive people in Japan from age 30 to 59 years. The number of patients with symptomatic PBC recorded by the nationwide epidemiological survey of the Japanese Government was 2459. Thus, we inferred the rate of symptomatic PBC among AMA-positive persons to be about 0.73% (2459/336,472). CONCLUSIONS: AMA is not a rare antibody in the general population, but few people develop recognizable PBC even if they have AMA.

Adult↗
PubMed2004

Hypoplasia of the right hepatic lobe associated with portal hypertension and idiopathic retroperitoneal fibrosis.

A 22-year-old man was referred to our hospital because of thrombocytopenia. Abdominal computed tomography (CT) revealed hypoplasia of the right hepatic lobe, the development of porto-systemic collateral vessels, splenomegaly and a periaortic soft-tissue mass. Laboratory tests and needle liver biopsy indicated no evidence of liver cirrhosis. Consequently, a diagnosis of hypoplasia of the right hepatic lobe associated with portal hypertension and idiopathic retroperitoneal fibrosis was established. Portal hypertension and hypersplenism was thought to be the cause of the thrombocytopenia. CT arterioportography revealed that anomalies of the portal venous system could have resulted in the hypoplasia of the right hepatic lobe. This is the first report describing hypoplasia of the right hepatic lobe accompanied by supervening idiopathic retroperitoneal fibrosis.

Abdomen↗
PubMed2004

Marked elevation of erythrocyte ribavirin levels in interferon and ribavirin-induced anemia.

BACKGROUND & AIMS: To elucidate the effects of blood ribavirin disposition on ribavirin-induced anemia, the relationship between erythrocyte ribavirin concentration and change in hematologic parameters was examined in interferon and ribavirin combination therapy for HCV eradication. METHODS: Nine HCV RNA-positive patients were treated with combination therapy including 11.3 +/- 1.2 mg.kg(-1).day(-1) of ribavirin. Blood concentrations of ribavirin and its phosphorylated metabolites were measured in plasma as well as erythrocyte. RESULTS: Blood ribavirin concentrations gradually increased to steady-state levels of 8.8 +/- 1.4 micromol/L and 1389 +/- 371 micromol/L in plasma and erythrocytes, respectively, within 3-4 weeks of initiating therapy. Erythrocyte phosphorylated metabolite levels (1215 +/- 302 micromol/L) were found to be exceedingly high, i.e., 87% of the measured erythrocyte ribavirin concentration. In contrast, plasma phosphorylated metabolite levels were undetectable. Positive correlation was found to exist between erythrocyte ribavirin concentrations and a decrease in hemoglobin (r = 0.620, P < 0.001). CONCLUSIONS: We concluded that marked elevation of erythrocyte ribavirin including its phosphorylated metabolites was associated with hemoglobin reduction, leading to interferon and ribavirin-induced anemia.

Anemia↗
PubMed2004

Prognostic index of cirrhotic patients with hepatic encephalopathy with and without hepatocellular carcinoma.

This study was carried out in Japanese patients to clarify the state of liver cirrhosis complicated by hepatic encephalopathy with and without hepatocellular carcinoma and its prognosis. The subjects were 100 patients with liver cirrhosis complicated by hepatic encephalopathy. Clinical data were investigated, and prognostic factors were extracted using Cox's proportional hazard model. The cumulative survival rate after the first episode of hepatic encephalopathy was 59.1% after 1 year, 48.3% after 2 years, and 22.2% after 5 years. The prognostic index (PI) was calculated using the following formula consisting of these six factors. PI = 0.806 x Child-Pugh classification + 1.149 x presence or absence of HCC + 0.024 x BUN + 0.036 x LDH + 0.093 x WBC + 0.381 x PIVKA-II. The PI value was suggested to be useful for the prognosis of liver cirrhosis after the first episode of hepatic encephalopathy.

Aged↗
PubMed2004

Newly-formed axonal branches of rat sciatic neurons sprouting in the spinal cord after peripheral axotomy.

A retrograde method of nerve tracing using a recombinant adenovirus was applied to experimental regeneration of peripheral nerves to study the sprouting position of the regenerating axon. This enabled us to see the entire length of the axons on a whole-mount neural specimen. The peroneal nerve was transsected and infected with this virus, and the tibial nerve was transsected and sutured in eight Wistar rats. Four to five weeks later, labelled axons appeared in the tibial nerve, some of which could be traced from the tibial nerve to the spinal cord without making a connection with other labelled fibres. Control experiments negated the possibilities of transneuronal immigration or contamination of the virus. When the peroneal and tibial nerves were double-labelled with fluorescent tracers four weeks after their transsection, double-labelled motor neurons appeared. Based on these findings, we conclude that regenerating branches do sprout in the spinal cord after axotomy.

Adenoviridae↗
PubMed2004

Liquid chromatography assay for routine monitoring of cellular ribavirin levels in blood.

Ribavirin-induced hemolytic anemia is one cause for cessation of combination therapy with alpha interferon 2b and ribavirin for hepatitis C infection. Determining cellular ribavirin levels in blood, including the levels of its phosphorylated metabolites, might be useful for predicting ribavirin-induced anemia, because the metabolites accumulate in erythrocytes. We simplified an assay method developed previously to make it suitable for routine monitoring of cellular ribavirin. Whole blood diluted with a sixfold volume of ice-cold distilled water was subjected to acid phosphatase digestion to convert phosphorylated ribavirin metabolites to free ribavirin. The resulting mixture, spiked with an internal standard, was treated by phenyl boronic acid column extraction, followed by reverse-phase high-performance liquid chromatography analysis. The calibration curve for ribavirin levels in whole blood was linear at concentrations of 5.3 to 1,024 microM (r(2) = 0.9999). Validation coefficients of variation for intra- and interday assays were 2.9 to 5.8% and 4.3 to 8.3%, respectively. We tested this method by monitoring blood ribavirin concentrations in two hepatitis C patients receiving alpha interferon 2b-plus-ribavirin combination therapy.

Antiviral Agents↗
PubMed2003

Profile and clinical significance of anti-nuclear envelope antibodies found in patients with primary biliary cirrhosis: a multicenter study.

Primary biliary cirrhosis (PBC) sera contain antibodies which recognize various nuclear envelope proteins of which antibody against gp210 has been proven to be diagnostic for disease. In contrast, the clinical significance of another nuclear envelope antibody, anti-p62 antibody has not been well investigated. In the present study, we have analyzed anti-nuclear envelope antibodies by indirect immunofluorescence and immunoblot using rat liver nuclear envelope proteins and wheat germ agglutinin-bound fraction. Test sera were obtained from 175 patients with PBC and from 120 controls. Anti-gp210, anti-lamina associated polypeptide 2, anti-lamin B receptor, and anti-p62 complex antibodies were detected with a frequency of 26% (46 of 175), 6% (11 of 175), 9% (16 of 175), and 13% (15 of 115), respectively. The confirmation of Scheuer's stage IV was made with a frequency of 27% (4 of 15) in PBC patients with anti-p62 complex antibody, in contrast to only 2% (2 of 100) in PBC patients without anti-p62 complex antibody. This difference was found to be statistically significant. The presence of anti-p62 complex antibody may be related with the progressive or advanced state of PBC.

Animals↗
PubMed2003

Immunoreactivity to pyruvate dehydrogenase complex-E2 in well-defined patients with autoimmune hepatitis: Western blot analysis.

Anti-mitochondrial antibodies (AMA) are frequently detected in sera from patients with primary biliary cirrhosis (PBC). Major autoantigens for AMA have been identified as members of the 2-oxoacid dehydrogenase enzyme complex family, with pyruvate dehydrogenase complex (PDC)-E2 showing strongest reactivity to AMA in PBC patients. Recently, anti-PDC-E2 has been found in patients with other diseases. Since frequency and significance of anti-PDC-E2 in patients with autoimmune hepatitis (AIH) remain obscure, we measured anti-PDC-E2 in sera from well-defined AIH cases by Western blotting using bovine heart mitochondrial protein and recombinant PDC-E2 protein as antigen sources. All 55 enrolled patients fulfilled the international diagnostic criteria for definite or probable AIH. Anti-PDC-E2 positivity showed concordance between native and recombinant antigens. Anti-PDC-E2 was detected in nine of 55 sera from AIH patients (16%). Variables including alkaline phosphatase (ALP) and IgM concentrations, effects of prednisolone, and pathologic findings concerning bile ducts showed no significant differences between anti-PDC-E2-positive and anti-PDC-E2-negative AIH patients. These data indicate that detection of anti-PDC-E2 is not rare in defined AIH, but anti-PDC-E2-positive AIH does not represent an intermediate entity in a clinical spectrum between AIH and PBC.

Journal Article↗