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Biomedical subjects

T Orii

Publications and source records attributed to T Orii.

At least 19 recordsLinked to original sources
PubMed2006

Effect of Hunter disease (mucopolysaccharidosis type II) mutations on molecular phenotypes of iduronate-2-sulfatase: enzymatic activity, protein processing and structural analysis.

Mucopolysaccharidosis II (Hunter disease), a lysosomal storage disorder caused by a deficiency of iduronate-2-sulfatase (IDS), has variable clinical phenotypes. Nearly 300 different mutations have been identified in the IDS gene from patients with Hunter disease, but the correlation between the genotype and phenotype has remained unclear. We studied the characteristics of 11 missense mutations, which were detected in the patients or artificially introduced, using stable expression experiments and structural analysis. The mutants found in the attenuated phenotype showed considerable residual activity (0.2-2.4% of the wild-type IDS activity) and those in the severe phenotype had no activity. In immunoblot analysis, both the 73-75 kDa precursor and processed forms were detected in the expression of 'attenuated' mutants (R48P, A85T and W337R) and the artificial active site mutants (C84S, C84T). The 73-75 kDa initial precursor was detected in the 'severe' mutants (P86L, S333L, S349I, R468Q, R468L). The truncated 68 kDa precursor form was synthesized in the Q531X mutant. The results of immunoblotting indicated rapid degradation and/or insufficiency in processing as a result of structural alteration of the IDS protein. A combination of analyses of genotype and molecular phenotypes, including enzyme activity, protein processing and structural analysis with an engineered reference protein, could provide an avenue to understanding the molecular mechanism of the disease and could give a useful tool for the evaluation of possible therapeutic chemical compounds.

Animals↗
PubMed2005

Heparan sulfate levels in mucopolysaccharidoses and mucolipidoses.

Glycosaminoglycans are accumulated in both mucopolysaccharidoses (MPS) and mucolipidoses (ML). MPS I, II, III and VII and ML II and ML III patients cannot properly degrade heparan sulphate (HS). In spite of the importance of HS storage in the metabolic pathway in these diseases, blood and urine HS levels have not been determined systematically using a simple and economical method. Using a new ELISA method using anti-HS antibodies, HS concentrations in blood and urine were determined in MPS and ML II and ML III patients. HS concentrations were determined in 156 plasma samples from MPS I (n = 23), MPS II (n = 26), MPS III (n = 24), MPS IV (n = 62), MPS VI (n = 5), MPS VII (n = 5), ML II (n = 8) and ML III (n = 3), and 205 urine samples from MPS I (n = 33), MPS II (n = 33), MPS III (n = 30), MPS IV (n = 82), MPS VI (n = 7), MPS VII (n = 9), ML II (n = 8) and ML III (n = 3). The ELISA method used monoclonal antibodies against HS. MPS I, II, III and VII and ML II and III patients had significant elevation in plasma HS, compared to the age-matched controls (p < 0.0001). Eighty-three out of 89 (93.3%) of individual values in the above MPS types and ML were above the mean +2SD of the controls. In urine samples, 75% of individual values in patients with those types were above the mean +2SD of the controls. In contrast to the previous understanding of the HS metabolic pathway, plasma HS levels in all five MPS VI and 15% of MPS IV patients were elevated above the mean +2SD of the controls. These findings suggest that HS concentration determined by ELISA, especially in plasma, could be a helpful marker for detection of the most severe MPS I, II, III, VI and VII and ML II, distinguishing them from normal populations.

Adolescent↗
PubMed2005

Keratan sulphate levels in mucopolysaccharidoses and mucolipidoses.

The mucopolysaccharidoses (MPS) is characterized by accumulation of glycosaminoglycans (GAGs), and mucolipidosis (ML) by accumulation of GAGs and sphingolipids. Each type of MPS accumulates specific GAGs. The lysosomal enzymes N-acetylgalactosamine-6-sulphate sulphatase and beta-galactosidase involve the stepwise degradation of keratan sulphate (KS). Deficiency of these enzymes results in elevation of KS levels in the body fluids and in tissues, leading to MPS IV disease. In this study, we evaluated blood and urine KS levels in types of MPS and ML other than MPS IV. Eighty-five plasma samples came from MPS I (n = 18), MPS II (n = 28), MPS III (n = 20), MPS VI (n = 3), MPS VII (n = 5) and ML (n = 11) patients while 127 urine samples came from MPS I (n = 34), MPS II (n = 34), MPS III (n = 32), MPS VI (n = 7), MPS VII (n = 9) and ML (n = 11) patients. KS levels were determined using the ELISA method. Plasma KS levels varied with age in both control and patient populations. In all age groups, the mean values of plasma KS in MPS and ML patients were significantly higher than those in the age-matched controls. Plasma KS values in four newborn patients were above the mean + 2SD of the age-matched controls (mean, 41 ng/ml). Overall, 85.9% of individual values in non-type IV MPS and ML patients were above the mean + 2SD of the age-matched controls. For urine KS levels, 24.4% of individual values in patients were above the mean + 2SD of the age-matched controls. In conclusion, KS in blood is elevated in each type of non-type IV MPS examined, in contrast to the conventional understanding. This finding suggests that measurement of KS level provides a new diagnostic biomarker in a wide variety of mucopolysaccharidoses and mucolipidoses in addition to MPS IV.

Adolescent↗
PubMed2001

Urinary organic acids in peroxisomal disorders: a simple screening method.

Using GC-MS, we studied urinary organic acids in 20 Japanese patients with peroxisomal disorders, including Zellweger syndrome (ZS), neonatal adrenoleukodystrophy, and single deficiency of peroxisomal beta-oxidation enzymes. Non-ketotic dicarboxylic aciduria with elevated sebacate/adipate molar ratio was observed in 19 of the 20 patients. Elevation of 2-hydroxysebacate and epoxydicarboxylic acids were seen in 13 and 18, respectively. Tyrosyluria was remarkable in all patients. In two ZS patients, we tracked the time course from birth to infancy, and all the above stated findings were detected, except for one sample. Urinary organic acid analysis is indeed useful for screening subjects with peroxisomal disorders.

Acids↗
PubMed2001

Epileptic seizures and structural abnormalities in a patient with holoprosencephaly.

In a patient with holoprosencephaly, partial seizures had various initial ictal symptoms, and ictal EEGs showed epileptogenic foci in the right and left brain. Partial seizures did not culminate in secondary generalized tonic-clonic convulsions. Characteristic malformed structures contribute to the absence of secondary generalization and the presence of Jacksonian-type propagation.

Brain↗
PubMed2001

Clinical, biochemical and genetic aspects and neuronal migration in peroxisome biogenesis disorders.

Peroxisome biogenesis disorders (PBDs) are severe autosomal recessive neurological diseases caused by a defect of peroxisomal assembly factors. Zellweger syndrome, the most severe phenotype, is characterized by hypotonia, psychomotor retardation and neuronal migration disorder. Neonatal adrenoleukodystrophy and infantile Refsum disease are milder phenotypes of this disease. Thirteen complementation groups have been established since the genetic heterogeneity of PBDs was elucidated in 1988. Eleven genes for PBDs have been identified either by a functional complementation cloning or by EST homology searches. In 1992, the first gene for PBDs, PEX2, was identified. It encodes peroxisomal integral membrane protein with a RING finger domain. PEX5 and PEX7 are the genes for peroxisomal targeting signal (PTS)-1 and -2 receptors, respectively. PEX3, PEX16 and PEX19 are considered to be required for the early stage of peroxisome biogenesis. PEX13 protein has an SH3 docking site that binds to the PTS-1 receptor. PEX1 and PEX6 encode ABC protein, and PEX10 and PEX12 also encode integral membrane protein, with RING finger. Temperature-sensitivity, whereby peroxisomal biogenesis and metabolic dysfunctions are restored at 30 degrees C in cells from mild phenotypes, is a useful event for predicting the clinical severity and for elucidation of peroxisome biogenesis. Investigations using knockout mice are expected to facilitate understanding of migration disorders.

Animals↗
PubMed2001

Antibody elimination by apheresis in living donor liver transplant recipients.

In the present study, we investigated retrospectively the indications and the efficacy of the elimination of preexisting antiallogeneic antibodies in liver transplant recipients. Three patients who were ABO blood type incompatible were subjected to plasmapheresis and double filtration plasmapheresis before the living donor liver transplantation (LDLTx), and the titers decreased to less than 8. After transplantation, plasmapheresis was also performed in 3 cases, and continuous hemodiafiltration in 1 case, and in 2 out of these 3 patients acute rejection was recognized. Two patients who were crossmatch positive were subjected to plasmapheresis before transplantation, and the T warm titers were reduced to less than Score 2. These 2 patients had no acute rejections after transplantation. We conclude that in liver transplant patients apheresis is effective to prevent acute rejection induced by preexisting anti-A and/or anti-B antibodies and anti-donor specific antibodies before transplantation, but it is not effective in a patient with accelerated humoral rejection occurring after transplantation.

ABO Blood-Group System↗
PubMed2001

Experience with artificial liver support in 16 living related liver transplant recipients.

This study was a retrospective investigation about the indication and efficacy of artifical liver support for liver transplant recipients. Apheresis was performed in 16 of 41 patients subjected to living related liver transplantation (LRLTx) as articial liver support, including plasmapheresis (PP) in 13 cases, continuous hemodiafiltration (CHDF) in 7 cases, and plasma adsorption (PA) in 2 cases. One patient with cryptogenic liver cirrhosis was subjected to PP before the LRLTx, and the result was satisfactory. On the contrary, the results of PP and CHDF for graft, respiratory, or cardiac failure were not acceptable. Only 1 patient survived despite multiple organ failure. Both PP and PA for patients with hyperbilirubinemia were effective and improved their critical conditions. We conclude that apheresis for liver transplant patients is effective to treat hyperbilirubinemia, but it is not indicated for respiratory and cardiac failure nor for hepatic failure.

Adolescent↗
PubMed2001

Evaluation of accumulated mucopolysaccharides in the brain of patients with mucopolysaccharidoses by (1)H-magnetic resonance spectroscopy before and after bone marrow transplantation.

In seven patients with mucopolysaccharidoses (1 Hurler, 1 Hurler-Scheie, 4 Hunter, 1 Sly), cranial (1)H-magnetic resonance spectroscopy was performed to evaluate the accumulation of mucopolysaccharides and biochemical changes in the CNS in vivo before and after bone marrow transplantation (BMT). In two of seven patients, (1)H-magnetic resonance spectroscopy was performed before and after BMT. Nuclear magnetic resonance spectra of dermatan sulfate and chondroitin sulfate-C and magnetic resonance spectroscopy of chondroitin sulfate-C and urine from patients with mucopolysaccharidoses showed resonance higher than the chemical shift of myoinositol in the brain (3.7 ppm). The resonance was considered to contain signals from mucopolysaccharide molecules. The resonance was measured as presumptive mucopolysaccharides (pMPS). In white matter lesions detected by magnetic resonance imaging, pMPS/creatine ratios and choline/creatine ratios were consistently higher than control ratios. In white matter without lesions, choline/creatine ratios were higher than control ratios. Patients with higher developmental quotient or intelligence quotient tended to show higher N:-acetylaspartate/creatine ratios and lower pMPS/creatine ratios in basal ganglia. After BMT, the pMPS/creatine ratio in white matter lesions of patient 3, with Hunter syndrome, was slightly decreased, but in none of the patients was the ratio ever below the control ratios, even 7 y after BMT. In white matter without lesions, the pMPS/creatine ratio in patient 3 was decreased to the control ratios after BMT, but although the choline/creatine ratios were gradually decreased, they remained higher than the control ratio, 2 y after BMT. These results suggest that evaluation of pMPS, choline, and N:-acetylaspartate by (1)H-magnetic resonance spectroscopy is an important technique that may provide useful biochemical information in vivo on the neurologic process and the efficacy of BMT in patients with mucopolysaccharidoses.

Adolescent↗
PubMed2001

[Examination of factors affecting efficacy and adverse effect, for the retrospective study of vancomycin hydrochloride (VCM)].

Vancomycin hydrochloride (VCM) is widely used for treatment of methicillin-resistant Staphylococcus aureus (MRSA) infections. However, this drug can cause sever adverse reactions, such as red neck syndrome, nephrotoxicity and ototoxicity. Thus, therapeutic drug monitoring (TDM) was bringing into effect for well effectiveness and to prevent side effects. In Kanto Medical Center NTT EC, TDM of VCM has been brought into effect since 1994. The date were accumulated from 200 patients. In this study, the retrospective research was carried out based on 117 cases selected from the above accumulated data, and then several factors such as VCM inducing side effect, a therapeutic effect, and the forecast of pharmacokinetic parameter using laboratory data were examined. Consequently, the high blood concentration trough level, the high value after 1 to 2 hours infusion, and the extension of t1/2 were brought forward as a nephrotoxicity causing factor, and more over each laboratory data (BUN, Cr, GOT, GPT, gamma-GTP, T-BiL, ALP, LDH) was high before infusion of VCM in patients with renal dysfunction. High value T-Bil and lower value TP were brought forward in patients with hepatic dysfunction, and high eosinophils and high blood concentration were brought forward after 1 or 2 hours infusion. In relation to side effects, it was found that the outbreak rate of side effects is high in patients with a complication of hypertension or diabetes. The administration term was considered as a factor which influences the therapeutic effects. The unchanged effect was 10.9 +/- 7.9 days, the improved effect was 14.6 +/- 9.3 days, the remarkably improved effect was 17.7 +/- 14.1 days. As the administration term gets longer, the improvement rate was recognized to be an upward tendency. The difference in significant effects was recognized between unchanged and remarkably unchanged (p < 0.05) effects. As the forecast of pharmacokinetic parameter using the laboratory data, VCMt1/2 showed a significant correlation between Cr and T-BiL, and it was VCMt1/2 = 8.56CR + 2.169T-Bil + 7.1. This result shows that VCMt1/2 can be estimated.

Adult↗
PubMed2000

Biochemical and structural analysis of missense mutations in N-acetylgalactosamine-6-sulfate sulfatase causing mucopolysaccharidosis IVA phenotypes.

Mucopolysaccharidosis IVA (MPS IVA; OMIM#253000), a lysosomal storage disorder caused by a deficiency of N -acetylgalactosamine-6-sulfate sulfatase (GALNS), has variable clinical phenotypes. To date we have identified 65 missense mutations in the GALNS gene from MPS IVA patients, but the correlation between genotype and phenotype has remained unclear. We studied 17 missense mutations using biochemical approaches and 32 missense mutations, using structural analyses. Fifteen missense mutations and two newly engineered active site mutations (C79S, C79T) were characterized by transient expression analysis. Mutant proteins, except for C79S and C79T, were destabilized and detected as insoluble precursor forms while the C79S and C79T mutants were of a soluble mature size. Mutants found in the severe phenotype had no activity. Mutants found in the mild phenotype had a considerable residual activity (1.3-13.3% of wild-type GALNS activity). Sulfatases, including GALNS, are members of a highly conserved gene family sharing an extensive sequence homology. Thus, a tertiary structural model of human GALNS was constructed from the X-ray crystal structure of N -acetylgalacto-samine-4-sulfatase and arylsulfatase A, using homology modeling, and 32 missense mutations were investigated. Consequently, we propose that there are at least three different reasons for the severe phenotype: (i) destruction of the hydrophobic core or modification of the packing; (ii) removal of a salt bridge to destabilize the entire conformation; (iii) modification of the active site. In contrast, mild mutations were mostly located on the surface of the GALNS protein. These studies shed further light on the genotype-phenotype correlation of MPS IVA and structure-function relationship in the sulfatase family.

Amino Acid Sequence↗
PubMed2000

The mouse N-acetylgalactosamine-6-sulfate sulfatase (Galns) gene: cDNA isolation, genomic characterization, chromosomal assignment and analysis of the 5'-flanking region.

Deficiency of lysosomal enzyme N-acetylgalactosamine-6-sulfate sulfatase (GALNS) leads to mucopolysaccharidosis IV A (MPS IV A), for which there is no definitive treatment so far. Although a number of mutations of the GALNS gene of MPS IV A patients have been described, pathogenesis of the disorder still remains elusive. In order to facilitate in vivo studies using model animals for MPS IV A, we isolated and performed molecular characterization of the mouse homolog of human GALNS. The 2.3-kb cDNA contains a 1560-bp open reading frame encoding 520 amino acid residues. The coding region has 84% similarity to the human GALNS cDNA at amino acid level. The mouse Galns gene was mapped by interspecific backcross analysis to the distal region of chromosome 8 where it co-segregates with Aprt. Northern blot analysis showed a wide expression of a single-copy gene, being higher especially in liver and kidney. The Galns gene was isolated from S129vJ genomic library and its genomic organization was characterized. The mouse Galns gene was about 50-kb long and organized into 14 exons and 13 introns. All intron-exon splice junctions conformed to the GT/AG consensus sequence except exon 8/intron 8 junction. Primer extension shows multiple transcription initiation sites between -44 and -75 although major transcription initiation site was observed at -90 bp from the ATG codon. The 5'-flanking region lacks canonical TATA and CAAT box sequences, but is G+C rich with 10 GC boxes (potential Sp1 binding sites), characteristic of a housekeeping gene promoter.

Amino Acid Sequence↗