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Biomedical subjects

T Yamano

Publications and source records attributed to T Yamano.

At least 37 records · Page 2Linked to original sources
PubMed2001

Molecular characterisation of glutamate dehydrogenase gene defects in Japanese patients with congenital hyperinsulinism/hyperammonaemia.

Congenital hyperinsulinism and hyperammonaemia (CHH) is caused by dysregulation of glutamate dehydrogenase (GDH). We characterised the GDH gene in two Japanese patients with CHH. Patient 1 showed late-onset and mild hypoglycaemic episodes and mild hyperammonaemia, compared with patient 2. In GDH activity of lymphoblasts, patient 1 showed twofold higher basal GDH activity than control subjects and mild insensitivity for GTP inhibition. Patient 2 showed severe insensitivity for GTP inhibition, and similar allosteric stimulation by ADP in the controls. Genetic studies identified heterozygous and de novo L413V and G446D mutations in patients 1 and 2, respectively. COS cell expression study confirmed that both mutations were disease-causing gene. The insensitivity for GTP inhibition in L413V and G446D was emphasised in COS cell expression system as a result of the dosage effect of mutant GDH gene. L413V showed less impairment of GDH than G446D based on biochemical and genetic results, which was consistent with the clinical phenotype. Based on the structure of bovine GDH, G446D was located in GTP binding site of pivot helix and its surroundings, while L413V was located in alpha-helix of antenna-like structure. These different locations of mutations gave different effects on GDH enzyme. The antenna-like structure plays an important role in GDH activity.

Animals↗
PubMed2001

Generation of cytotoxic T lymphocytes by MHC class I ligands fused to heat shock cognate protein 70.

Immunization with gp96 and heat shock cognate protein 70 (hsc70) purified with in vivo bound naturally occurring peptides or bound to synthetic peptides by in vitro reconstitution has been shown to induce peptide-specific cytotoxic T lymphocytes (CTL). In addition, mycobacterial heat shock protein 70 covalently fused to ovalbumin (OVA)-derived fragments has been shown to generate MHC class I-restricted CTL responses. Here, we genetically fused five different CTL epitopes, including peptides derived from Plasmodium yoelii circumsporozoite protein, tumor antigens, HY antigen and OVA, to either the N- or C-terminus of murine hsc70 and expressed the resulting proteins in Escherichia coli. Vaccination with all five fusion proteins induced peptide-specific CTL, indicating that no cognate flanking regions of CTL epitopes are necessary for the immune response. The point of injection was crucial for CTL induction. CD4(+) T cells were not required for the priming of CD8(+) T cells and vaccination with bone marrow-derived dendritic cells pulsed with hsc70 fusion proteins also elicited CTL responses. Furthermore, by using deletion mutants of hsc70, we identified amino acid residues 280-385 of hsc70 as the region most critical for inducing the CTL response.

Animals↗
PubMed2001

Hemadsorption expressed by cloned H genes from subacute sclerosing panencephalitis (SSPE) viruses and their possible progenitor measles viruses isolated in Osaka, Japan.

Most subacute sclerosing panencephalitis (SSPE) viruses, including our Osaka-1, -2, and -3 strains isolated in Osaka, have shown negative hemadsorption (HAD) by African green monkey red blood cells. This property has been thought to be characteristic of SSPE virus as compared to the positive reaction of the standard Edmonston strain of measles virus (MV). However, this assumption has become quite obscure because MV mutates frequently at the genetic level during its multiplication and also because recent field strains isolated by lymphoblastoid cell lines have shown negative HAD. To investigate the above issue, the nucleotide sequences of the hemagglutinin (H) genes from SSPE virus Osaka-1, -2, or -3 strains were compared to those of various MV field strains isolated in Osaka by Vero cells. The H gene sequences of three SSPE strains were relatively conserved without such biased hypermutation as had been observed in the matrix (M) gene of three SSPE strains. However, this analysis of the H gene sequence of the SSPE viruses enabled us to deduce possible progenitor MVs, which are in agreement with the deduction from the M gene analysis we reported previously. The HAD of Vero cells transfected with the cloned H cDNAs from the SSPE strains and their progenitors suggested that negative HAD of the SSPE viruses has been maintained as one of original properties of the progenitor MVs rather than having been acquired as an altered one during long-term persistent infection in the brains of patients with SSPE.

Amino Acid Sequence↗
PubMed2000

Attenuation of cadmium-induced liver injury in senescent male fischer 344 rats: role of Kupffer cells and inflammatory cytokines.

In the previous study we showed that senescent male Fischer 344 rats were resistant to Cd-induced hepatotoxicity compared with young-adult rats. In the present study we investigated the role of Kupffer cells and inflammatory cytokines in this effect of aging. The phagocytic activity of Kupffer cells, determined as the removal of carbon from blood, was stimulated by the administration of a hepatotoxic dose of Cd (3 mg/kg sc) in young-adult (5 months) rats but not in old (28 months) rats. Hepatic concentrations of interleukin (IL)-1beta and cytokine-induced neutrophil chemoattractant (CINC), but not of tumor necrosis factor-alpha or IL-6, were elevated in young rats treated with Cd. In old rats, however, the increase in IL-1beta produced by Cd was not statistically significant and the increase in CINC was much lower than in young-adult rats. Pretreatment with gadolinium chloride or cyclosporin A inhibited the elevations in hepatic cytokines and attenuated Cd-induced liver damage, assessed on the basis of serum alanine aminotransferase and sorbitol dehydrogenase activities. Cd-induced hepatotoxicity in the different treatment groups correlated well with hepatic levels of CINC (r = 0.98, p < 0.001) but not with those of IL-1beta. The results suggest that (1) Kupffer cell activation is essential for inflammatory liver damage from Cd, (2) IL-1beta and CINC are important mediators of the inflammatory response induced by Cd, and (3) the attenuation of Cd-induced liver injury in senescent rats is caused by an impairment in Kupffer cell activation, leading to a lower production of CINC and less inflammatory liver injury.

Age Factors↗
PubMed2000

Mechanisms of cadmium-mediated acute hepatotoxicity.

The mechanism of cadmium-mediated acute hepatotoxicity has been the subject of numerous investigations and although some uncertainties persist, sufficient evidence has emerged to provide a reasonable account of the toxic process. Acute hepatotoxicity involves two pathways, one for the initial injury produced by direct effects of cadmium and the other for the subsequent injury produced by inflammation. Primary injury appears to be caused by the binding of Cd2+ to sulfhydryl groups on critical molecules in mitochondria. Thiol group inactivation causes oxidative stress, the mitochondrial permeability transition, and mitochondrial dysfunction. Although cadmium may injure hepatocytes directly, there are compelling reasons to believe that hepatocellular injury is produced in vivo as the result of ischemia caused by damage to endothelial cells. Secondary injury from acute cadmium exposure is thought to occur from the activation of Kupffer cells and a cascade of events involving several types of liver cells and a large number of inflammatory and cytotoxic mediators. In this regard, it is clear that Kupffer cell activation and neutrophil infiltration are important events in the toxic process, and the involvement of proinflammatory cytokines and chemokines has also been implicated. The precise roles of the soluble mediators of inflammation warrant further investigation.

Animals↗
PubMed2000

Clonal expansion in evolution of chronic hepatitis to hepatocellular carcinoma as seen at an X-chromosome locus.

Clonal analysis has shown that hepatocellular carcinoma arises from a single cell. However, the clonality of precancerous lesions and adjacent nonneoplastic tissues is not clear. We analyzed a human androgen receptor locus to elucidate the clonal state of liver tissues including post-hepatitic lesions associated with hepatocarcinogenesis. The analysis was based on a restriction fragment length polymorphism involving an androgen receptor locus on the X chromosome, taking advantage of physiologic random inactivation by methylation of 1 of 2 X chromosomes in females during embryogenesis. Clonality was assessed in 79 randomly located tissue samples microdissected from noncirrhotic liver, including a total of 40 morphologically normal sites in 4 normal livers and 39 sites from a single HCV-infected liver. In addition, 51 regenerative nodules, 4 areas of adenomatous hyperplasia, and 18 hepatocellular carcinomas were sampled. All samples were obtained from livers involved by various neoplasms. Eight of forty samples (20.0%) from the four normal livers and 20 of the 39 samples (51.3%) from the single HCV-infected liver showed a monoclonal pattern. Moreover, 30 of 51 regenerative nodules (58.9%) showed a monoclonal pattern. No histologic differences were evident between mono- and polyclonal nodules. On the other hand, the 18 carcinomas and 4 areas of adenomatous hyperplasia all were monoclonal. Mean calculated monoclonal areas of normal liver and liver with chronic hepatitis were 1.1 and 3.3 mm(2). Our results suggest that areas representing a single clone of hepatocytes are present in normal liver, and these progressively expand as changes advance from chronic hepatitis to hepatocellular carcinoma.

Aged↗
PubMed2000

Amplification of transgene expression in vitro and in vivo using a novel inhibitor of histone deacetylase.

Enhancement of transgene expression is an important issue in human gene therapy. Here we describe a novel system for enhancing transgene expression by cointroduction of plasmid DNA with FR901228, a water-soluble histone deacetylase inhibitor. When a luciferase expression vector was cointroduced into cells with FR901228, luciferase gene expression was enhanced 50-fold in the mouse melanoma cell line B16-F1 and 5200-fold in NIH3T3 cells in comparison to cells without the drug. Luciferase gene expression enhancement was dependent on both drug dose and treatment time. Acetylated histones increased in accordance with drug dose, and the activation of gene expression occurred at the transcriptional level. The stimulation of luciferase gene expression by FR901228 was also observed in a B16-F1 clone stably expressing luciferase. Cointroduction of the luciferase plasmid with FR901228 into a B16-F1 tumor mass activated luciferase gene expression 3- to 4-fold. Thus, activation of transgene expression by FR901228 may serve as a new tool for gene therapy.

Animals↗
PubMed2000

Angiomyolipoma arising in the thigh.

A 41-year-old man presented with an asymptomatic mass in the right medial thigh. Magnetic resonance imaging (MRI) revealed a well-demarcated, 10-cm mass in the right adductor muscles. The margins of the mass exhibited high signal intensity and the rest showed low or iso signal intensity on T1-weighted MR images. However, the high signal intensity was decreased on T2-weighted images with fat suppression. The central part of the tumor was of inhomogeneous high signal intensity on T2-weighted images; after Gd-DTPA injection it enhanced in homogeneously on T1-weighted images with fat suppression. On dynamic computed tomography (CT) in the arterial phase, there were strongly enhancing spotty areas in the tumor. At surgery, a yellow-whitish tumor was resected and a pathological diagnosis of angiomyolipoma (AML) in the thigh was made.

Adipose Tissue↗
PubMed2000

Heterotopia in microcephaly induced by cytosine arabinoside: hippocampus in the neocortex.

Pregnant mice were injected intraperitoneally with cytosine arabinoside (Ara-C) on days 13.5 and 14.5 of pregnancy. The brains of their offspring were studied histologically and histochemically. In addition to dysgenic microcephaly, nodular structures consisting of cells with a relatively homogeneous morphology were observed in the depths of the cerebral cortex. The cell clusters were first seen around postnatal day 4, and had a cellular continuity with the disarrayed pyramidal cell layer in the CA 1 region of the hippocampus. Golgi-Cox staining showed a number of pyramidal-shaped cells in the clusters. Morphologically, they resembled the pyramidal neurons of the hippocampus. Immunohistochemical examination, using anti-serotonin or anti-tyrosine hydroxylase antibodies, also indicated similarities between the cell clusters and the pyramidal cell layer. It is, therefore, proposed that the cell clusters consisted of heterotopic pyramidal cells of the hippocampus. A few synaptic structures could already be detected in the heterotopic cell clusters on postnatal day 3 by electron microscopy. This early establishment of synaptic contact with related neurons may have caused the heterotopic localization of the pyramidal cells.

Abnormalities, Drug-Induced↗
PubMed2000

A long-term survival case of multiple hepatocellular carcinoma with metachronous lymph node metastasis.

A long-term survival case of multiple hepatocellular carcinoma (HCC) with metachronous metastasis to a lymph node is reported. The patient, a 66-year-old woman, had two primary HCC nodules, one each in the left and right hepatic lobes, which were resected. She developed a lymph node lesion and a secondary HCC 45 and 62 months after the first operation, respectively. She has been well for the 7 years since the first operation despite undergoing hepatic resection for HCC twice as well as lymph node resection. Clonal analysis, based on the methylation pattern of the X chromosome-linked androgen receptor gene, suggested that the two primary tumors were multicentric and that the lymph node lesion had arisen by metastasis from the primary tumor in the right hepatic lobe.

Journal Article↗
PubMed2000

Decreased plasma levels of fibronectin in amyotrophic lateral sclerosis.

OBJECTIVES: Fibronectin (FN) possesses a wide range of biological functions. However, the role of plasma FN in vivo has not yet been established and there have been no published studies of plasma FN in ALS. The aim of this study was to measure plasma FN in ALS patients. MATERIAL AND METHODS: We measured plasma FN levels in 28 ALS patients, 18 control subjects with other neurologic or muscular diseases (control group A) and 21 healthy adults (control group B). The age and sex distributions among the 3 groups were comparable. RESULTS: Plasma FN levels were significantly lower in ALS patients than in control groups A and B. There was also a significant negative correlation between plasma FN levels and duration of illness in ALS patients. CONCLUSION: These data suggest that a metabolic alteration of FN may take place in ALS and that the measurement of plasma FN may serve as an indicator of clinical progression of this disorder.

Amyotrophic Lateral Sclerosis↗
PubMed2000

Serum interferon-gamma-inducing factor/IL-18 levels in primary biliary cirrhosis.

Primary biliary cirrhosis is an autoimmune disease of the liver in which T helper 1 cytokines predominate over those of T helper 2 in the pathogenesis. Interleukin- 18 (IL-18), for which the gene was recently cloned, is a novel T helper 1 cytokine, which augments interferon-gamma production. We designed this study to clarify the role of IL-18 in primary biliary cirrhosis and to examine whether serum IL-18 level can be a prognostic indicator for the disease. Serum IL-18 levels were measured using an enzyme linked immuno sorbent assay with mouse monoclonal antibodies. Twenty-two healthy volunteers, 31 patients with primary biliary cirrhosis (Scheuer's stage I, 13; II, 10; and IV, 8), 20 patients with autoimmune hepatitis, 11 patients with virus-related liver cirrhosis and six patients with obstructive jaundice were enrolled. Significant differences of serum IL-18 levels were observed between patients with Scheuer's stage IV and those with stage I, or II, virus-related liver cirrhosis and obstructive jaundice (P < 0.05). The IL-18 levels in primary biliary cirrhosis increased according to the disease progression, and fell promptly after living-related liver transplantation. Moreover, serum IL-18 levels in primary biliary cirrhosis were correlated with serum bilirubin concentrations and the Risk scores of the Mayo Clinic prognostic model for the disease. The IL-18 levels observed in patients with autoimmune hepatitis were also elevated, and correlated with the activity of the disease. These results indicate that serum interleukin-18 levels reflect the severity of primary biliary cirrhosis, the activity of autoimmune hepatitis, and may be an additive prognostic indicator in primary biliary cirrhosis.

Autoimmune Diseases↗
PubMed2000

Serum markers of type I collagen synthesis and degradation in amyotrophic lateral sclerosis.

Collagen abnormalities in the skin and spinal cord have been reported in amyotrophic lateral sclerosis (ALS) patients. Serum carboxyterminal propeptide of type I procollagen (PICP) and the carboxyterminal cross-linked telopeptide of type I collagen (ICTP) reflect type I collagen synthesis and degradation, respectively. However, there has been no study concerning PICP or ICTP in ALS. We studied collagen contents of the skin and measured serum levels of PICP and ICTP in patients with ALS and control subjects. Serum PICP levels were significantly lower in ALS patients than in controls. Serum ICTP levels were significantly higher in ALS patients than in controls, and there was an appreciable positive correlation between serum ICTP levels and the duration of illness in ALS patients. In ALS patients, the collagen content of the skin was significantly smaller than in controls and indicated a progressive decrease in relation to illness. In addition, there was a significant negative correlation between serum ICTP concentrations and the collagen content of the skin in ALS patients. These data suggest that increased ICTP levels and decreased serum PICP levels may reflect unique changes in the skin, with a predominance of degradation compared to the synthesis of type I collagen in ALS.

Adult↗
PubMed2000

Myelodysplastic syndrome with clonal eosinophilia accompanied by eosinophilic pulmonary interstitial infiltration.

We report a case of de novo myelodysplastic syndrome with clonal eosinophilia (MDS-Eo) and eosinophilic pulmonary interstitial infiltration, confirmed by autopsy. Cytogenetic study using Giemsa banding identified 47,XY,+1,der(1;7)(q10;p10),+8 in the marrow cells. Simple Giemsa staining revealed the same chromosomal aberration in metaphase spreads with eosinophilic granules, indicating the clonal proliferation of eosinophils. To our knowledge, our case is the 6th reported case of MDS-Eo with cytogenetically confirmed clonal eosinophilia, and the first autopsy of MDS-Eo. A review of the literature combined with our findings suggests that this type of chromosomal aberration might be involved in the as yet unknown pathogenesis of MDS-Eo.

Aged↗
PubMed2000

[Evaluation of hepatic toxicity following high-dose 5-FU arterial infusion chemotherapy: analysis of 42 cases of colorectal liver metastases].

The regional toxicity of an anticancer agent for normal liver tissue following hepatic arterial infusion chemotherapy (HAI) was evaluated in terms of morphology, function, and histopathology. Forty-two patients(M:F = 30:12; mean age, 59.9 years) with liver metastases from colorectal cancer were treated with HAI using a totally implantable vascular access port system from July 1994 to March 1999. The regimen used here was so-called weekly high-dose 5-fluorouracil(5-FU) infusion(5-FU, 1,000 mg/m2/week). Volume measurement of the liver demonstrated not only whole liver atrophy including the tumor but also volume reduction of the non-tumorous lobe. Atrophic change of the liver was seen in patients who were administered over 20 g/m2 of 5-FU(p < 0.01). The CT attenuation values of the liver were examined, and fatty infiltration was seen in six patients. Histologic examination of liver biopsies from the non-tumorous part revealed steatosis and infiltration of inflammatory cells in the portal triad, which were not seen in specimens prior to HAI. On clinical laboratory findings, enzymes representing bile duct, including alkaline phosphatase, leucine amino peptidase, and gamma-glutamyltranspeptidase, were increased in 22 patients. In terms of regional toxicity for long-term HAI, 20 g/m2 of 5-FU, is the key dose at which to consider temporary cessation or dose reduction.

Adult↗
PubMed1999

Attenuation of cadmium-induced liver injury in senescent male fischer 344 rats: role of metallothionein and glutathione.

The influence of aging on the sensitivity of the liver to the acute toxicity of cadmium has not been studied previously in adult rats. In this study hepatotoxicity caused by a single sc injection of CdCl(2) was compared in 5-, 18-, and 28-month-old male Fischer 344 rats. Doses of Cd were adjusted on the basis of the mean lean body mass for each age group of rats, and liver injury was evaluated 24 h after treatment. Cd treatment produced substantial increases in serum alanine aminotransferase (ALT) and sorbitol dehydrogenase (SDH) activities in 5- and 18-month-old rats, whereas no significant increases were observed in 28-month-old rats. Histologic examination of representative livers from each age group confirmed the findings for serum enzyme activity; hepatocellular necrosis was observed only in livers from 5- and 18-month-old rats. The attenuation of Cd hepatotoxicity in senescent rats did not appear to be related to pretreatment levels of metallothionein or glutathione. Likewise, resistance to Cd could not be explained on the basis of metallothionein induction, which decreased as a function of aging. Thus, the mechanisms that account for the postmaturational decline in sensitivity to Cd do not appear to be associated with alterations in levels of the major factors that protect against Cd-induced hepatotoxicity.

Aging↗