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Biomedical subjects

A Yoshioka

Publications and source records attributed to A Yoshioka.

At least 127 records · Page 7Linked to original sources
PubMed1997

The revised classification of von Willebrand disease including the previously masqueraded female hemophilia A (type 2N)

The revised classification of von Willebrand disease was proposed by the working committee (Chairperson: J.E. Sadler) and approved by the Scientific and Standardization Committee/the International Society on Thrombosis and Hemostasis in 1993. It consists of three major types; type 1 with decreased level of normal von Willebrand factor (VWF) and type 3 with complete deficiency of VWF as quantitative abnormality, and type 2 with qualitative anomaly of VWF subcategorized into 2A, 2B, 2M and 2N, respectively, depending on the functional abnormalities (decrease of GPIb binding with defect of VWF large multimers, increase of GPIb binding, decrease of GPIb binding with VWF large multimers, decrease of FVIII binding). This classification is frequently quoted in the USA and Europe. We introduce this classification and review again the structural abnormalities of VWF, including the previously masqueraded female hemophilia A (type 2N).

Female↗
PubMed1997

Factor VIII gene analysis in Japanese CRM-positive and CRM-reduced haemophilia A patients by single-strand conformation polymorphism.

Haemophilia A is the most common X-linked blood coagulation disorder; it is caused by deficiency of factor VIII activity (FVIII:C). Half of the affected patients do not have detectable levels of FVIII protein in their plasma, whereas about 5% have normal levels of the FVIII antigen (FVIII:Ag) (> 50 u/dl), and are called cross-reacting material (CRM) positive (CRM+ or A+). About 45% of patients have reduced levels of the FVIII:Ag (1-50 u/dl), classified as CRM reduced (CRM[R] or A[R]). We screened the FVIII gene of 13 Japanese patients (five CRM+ and eight CRM[R]) by single-strand conformation polymorphism, and identified 11 different mutations in 13 patients by analysing all 26 exons (Trp255Cys, Tyr473Cys, Gly479Arg, Arg531His, Thr667Arg, Arg1689Cys, Arg1941Gln, Arg2150His, Arg2159Cys, Thr2245Ala and Gly2285Val). Seven mutations were identified in the A domains (four in the A2 domain). All the mutations are point mutations resulting in missense codons. Four mutations (Trp255Cys, Thr667Arg, Thr2245Ala and Gly2285Val) have not been described previously.

Enzyme-Linked Immunosorbent Assay↗
PubMed1997

Neonatal lupus erythematosus: HLA-DR and -DQ distributions are different among the groups of anti-Ro/SSA-positive mothers with different neonatal outcomes.

Neonatal lupus erythematosus (NLE) is an antibody-mediated disorder of infants characterized by two major clinical manifestations; cutaneous lupus lesions and congenital heart block (CHB). The disease is associated with placentally transferred maternal anti-Ro/SSA and/or La/SSB antibodies. There is a tendency for the same disease expression to occur within a sibship. To reveal a possible association of class II MHC genes with maternal anti-Ro/SSA autoimmune responses and neonatal outcomes in NLE with a relatively homogeneous ethnic background, haplotype, and allele distributions were analyzed based on the PCR-RFLP results in 26 Japanese anti-Ro/SSA-positive mothers from three groups defined by neonatal outcomes. The results were as follows: (i) maternal HLA-DR5 haplotype DRB1*1101-DQA1*0501-DQB1*0301 and individual class II alleles making up this haplotype were significantly associated with neonatal cutaneous lupus but not CHB. Conversely, maternal HLA-DQB1*0602 carried on HLA-DR2 haplotypes was associated with CHB but not cutaneous NLE; (ii) HLA-DQA1 alleles with glutamine at position 34 of the first domain, which have reportedly been associated with the autoimmune responses to Ro/SSA antigens in other ethnic groups, were increased in the mothers of infants with cutaneous involvement; and (iii) there was no particular class II HLA profile that distinguished the disease manifestations in infants. These findings suggest that specific maternal MHC class II genes might correlate with specific neonatal outcomes in NLE.

Adult↗
PubMed1997

Preschool sarcoidosis mimicking juvenile rheumatoid arthritis: the significance of gallium scintigraphy and skin biopsy in the differential diagnosis.

Preschool sarcoidosis occurring in children less than 6 years old is rare and characterized by the triad of skin, joint and eye manifestations without any pulmonary lesion. Because of similar clinical manifestations, the diagnosis of preschool sarcoidosis and juvenile rheumatoid arthritis (JRA) is confusing. A girl with preschool sarcoidosis, initially diagnosed and treated as having JRA, is reported here. Ophthalmologic examinations revealed posterior involvement of the eye. A gallium scintigram of the head showed panda appearance. Biopsy of the cutaneous lesion demonstrated non-caseating granuloma. Gallium scanning may be an important clue to correct diagnosis.

Arthritis, Juvenile↗
PubMed1997

Early cardiac failure in a child with Becker muscular dystrophy is due to an abnormally low amount of dystrophin transcript lacking exon 13.

Two Japanese brothers with Becker muscular dystrophy were shown by polymerase chain reaction (PCR) and cDNA sequence analysis to produce a dystrophin gene transcript lacking a single exon: that is, number 13. Despite having the same deletion mutation, the brothers showed clearly different clinical phenotypes: the younger brother developed cardiac failure at the age of nine, while the elder brother was asymptomatic. As alternative splicing was not responsible for this clinical difference, the amount of dystrophin transcript was examined by using reverse transcription semi-nested and parallel PCR. The results showed that the amount of the dystrophin transcript in the younger brother was 20% of that of the elder brother. This finding suggested that lesser amount of dystrophin transcript in the younger brother was responsible for the early onset of cardiac failure. This would represent a novel molecular mechanism for dystrophinopathy.

Cardiac Output, Low↗
PubMed1997

Neonatal lupus erythematosus: studies on HLA class II genes and autoantibody profiles in Japanese mothers.

Neonatal lupus erythematosus (NLE) is a rare disorder of neonates characterized by two major clinical manifestations: congenital heart block and cutaneous lupus lesions. The disease is associated with placentally transferred maternal anti-Ro/SSA and/or La/SSB antibodies. To clarify possible class II HLA associations with maternal autoantibody responses, haplotypic and allelic distributions, along with the polymorphism of the MHC class II HLA alleles, were analyzed based on PCR-RFLP results in 25 Japanese mothers of two groups defined by precipitating autoantibody profiles. Among mothers with both anti-Ro/SSA and anti-La/SSB antibodies, but not those with anti-Ro/SSA alone, the class II haplotypes DRB1*1101-DQA1*0501-DQB1*0301 and DRB1*08032-DQA1*0103-DQB1*0601 as well as individual class II alleles DRB1*1101, DRB1*08032 and DQB1*0301 showed significantly increased frequencies compared to those in normal controls. All anti-Ro/SSA and anti-La/SSB positive mothers carried DRB1 alleles that shared the same amino acid residues at positions 14-31 and 71 of the DRB1 chain. These mothers also carried homozygous or heterozygous DQ6 and DQ3 alleles that shared the same amino acid residues at positions 27-36 and 71-77 of hypervariable regions of the DQB1 chain. Furthermore, all mothers with both anti-Ro/SSA and anti-La/SSB were homozygous for DPB1*0501. Nine of 10 anti-Ro/SSA and anti-La/SSB-positive mothers, but only 6 of 15 mothers with anti-Ro/SSA alone, had affected infants. Thus, our findings suggest that there may be immunogenetic differences among mothers according to their autoantibody profiles, and that mothers with both anti-Ro/SSA and anti-La/SSB are more likely to have infants with NLE than mothers with anti-Ro/SSA alone.

Animals↗
PubMed1997

Abnormal proteolytic processing of von Willebrand factor Arg611 Cys and Arg611His.

The structural and functional properties of plasma and platelet vWF were studied in 8 patients (5 unrelated families) with vWD demonstrating a mutation at position 611 (R611C or R611H). Following reduction, electrophoresis and immunoblotting with a polyclonal anti-reduced vWF antibody, abnormal proteolysis of vWF was demonstrated in plasma and to a lesser extent in platelets from all patients, leading to the formation of a unique 209 kDa fragment undetectable in control as well as in type 2A, 2B or 2N vWF. Immunoblotting with MoAbs to reduced vWF showed that the C-terminal end of the 209 kDa fragment was located beyond residue 1744 of the subunit and that its N-terminus was between residues 523 and 1114. Multimeric analysis of patients vWF showed an abnormal pattern in both plasma and platelets, with a moderate decrease of the HMW multimers together with a significant increase of the lowest MW forms. The specific sensitivity of vWF R611C and vWF R611H to proteolysis was further evidenced using V-8 protease. In all patient's samples the enzyme produced a unique monomeric 80 kDa fragment, absent in V-8 digested normal vWF, which overlapped the N-terminal part of the subunit. The functional analysis of vWF showed a markedly decreased affinity of mutated plasma vWF for platelet GPIb in the presence of ristocetin. Infusion of DDAVP in two of these patients did not lead to significant platelet count change. It induced a limited increase of the HMW multimers in plasma together with a poor correction of the vWF binding to platelet GPIb. In conclusion, our data demonstrate that in addition to a normal proteolysis, vWF mutated at position 611 undergoes a specific cleavage in plasma and platelets. In contrast to the increased proteolysis observed in type 2A and 2B patients' plasma, this additional cleavage produced a unique 209 kDa species but maintained a HMW multimer-like structure of vWF R611C and R611H.

Arginine↗
PubMed1997

[A case of Wilson-Mikity syndrome with marked and monoclonal elevation of IgM in blood].

Wilson-Mikity syndrome, a chronic respiratory insufficiency occurring in premature newborn infants, is known to show an elevation of serum IgM, but its etiology is obscure. We studied the immunological properties of IgM in a female infant of this syndrome, whose IgM in cord blood was very high level at 639.1 mg/dl with monoclonal elevation. The IgM bound to protein(s) in human umbilical venous endothelial cells and in human lung tissue. However, IgMs from this patient after recovery, from patient's mother and from another normal newborn did not bind to the proteins. Tissue-binding activity of the patient's IgM may be associated with tissue damages in this syndrome.

Female↗
PubMed1997

Factor VIII Ise (R2159C) in a patient with mild hemophilia A, an abnormal factor VIII with retention of function but modification of C2 epitopes.

We found a patient with mild hemophilia A who had no detectable factor VIII antigen (FVIII:Ag), as shown by two-site ELISA using inhibitor alloantibodies (TK). We then analyzed A2, A2/B, and C2 antigen of the patient's DDAVP-induced FVIII using several anti-FVIII monoclonal antibodies. Factor VIII activity (FVIII:C) was increased from 12 to 42 U/dl by the administration of DDAVP. The DDAVP-induced increases in the A2 and A2/B antigens were 40 and 36 U/dl, respectively. However, the increase in the C2 antigen was only 7.5 U/dl. SSCP analysis and subsequent sequencing demonstrated an Arg to Cys transition at codon 2159. The anti-FVIII:C titer of monoclonal antibody, NMC-VIII/5 which recognized the C2 domain, against normal plasma was 450 Bethesda U/mg of IgG. However, the titer against DDAVP-treated patient's plasma was only 15 Bethesda U/mg. We also tested DDAVP-induced increase in the FVIII:Ag in another mild hemophilia A patient with the same mutation at Arg2159. Increase in his C2 antigen levels was only 19% of those in the A2 and A2/B antigen. We designate this abnormal FVIII as FVIII Ise. Our results show that a missense mutation at Arg2159 to Cys modifies the antigenicity of the C2 domain.

Adolescent↗
PubMed1997

[A case of postencephalitic intractable partial epilepsy with multiple brain lesions demonstrated by MRI].

We encountered a case of focal encephalitis. A 5-year-old boy developed high fever and he was admitted to our hospital on the third day with generalized tonic-clonic convulsions. Cerebrospinal fluid showed slight pleocytosis. CT showed diffuse low-density area in the left temporal, parietal and occipital regions. T2 weighed MRI showed swelling and hyperintense regions in the left temporal, parietal and occipital cortex. With the disappearance of generalized convulsion, the cortical swelling improved. But aphasia and intractable complex partial seizures appeared. On MRI, the atrophic findings of the left hippocampus and temporal lesion became developed. We considered this case corresponds to focal encephalitis related to "a peculiar type of post-encephalitic/encephalopathic epilepsy" reported by Awaya et al.

Child↗
PubMed1997

[Ibudilast prevents oligodendroglial excitotoxicity].

Previously we have demonstrated that cells of oligodendroglial lineage express non-N-methyl-D-aspartate (NMDA) glutamate receptor (GluR) genes and are damaged by kainate induced Ca2+ influx via non NMDA GluR channels of the alpha-amino-3-hydroxy-5-methyl 4 isoxazole propionate (AMPA) type, representing oligodendroglial excitotoxicity. We here present the finding that ibudilast, which is used clinically for treat patients with asthma and cerebrovascular diseases, prevents oligodendroglia excitotoxicity. The oligodendrocyte like cells (OLC), differentiated from the CG-4 cell line established from rat oligodendrocyte-type 2 astrocyte (O-2A) progenitor cells, were exposed to 2 mM kainate for 24 h and cell death was evaluated by measuring activity of lactate dehydrogenase (LDH) released into the culture medium. Kainate induced cell death was prevented by 10 to 100 microM ibudilast, which increased intracellular cAMP. A 45Ca2+ influx study revealed that ibudilast attenuated kainate-induced Ca2+ influx. Inhibition of kainate-induced Ca2+ influx by ibudilast was decreased by H-89, a protein kinase A (PKA) inhibitor, but increased by okadaic acid, an inhibitor of phosphatase 1 and 2A. Therefore, we concluded that ibudilast prevented oligodendroglial excitotoxicity by a PKA-dependent phosphorylation process resulting in decreased kainate-induced Ca2+ influx.

Animals↗
PubMed1997

[Transient inhibitors developed in two cases of hemophilia A].

This report describes the transient development of inhibitors in two cases of hemophilia A. Case 1 was an 8-month-old boy who suffered from subcutaneous hematoma with extremely low level (1.5%) of plasma factor VIII activity (F VIII:C). He showed an inhibitor titer of 2.5 Bethesda units (BU)/ml when he suffered from measles at age 24 months with poor clinical response to factor VIII. This inhibitor elevated to 11.6 BU/ml at 29 months, but completely disappeared at 32 months. Case 2 was a 5-month-old boy who suffered from subcutaneous hematoma with extremely low level (< 1%) of plasma F VIII:C. At 8 months his inhibitor titer peaked at 19 BU/ml but subsequently declined to 11.5 BU/ml at 12 months and completely disappeared at 14 months. A review of the literature revealed that the median (range) titer of transient inhibitor initially developed at 2 (0.5-19) BU/ml on 225 (79-448) days, immediately peaked at 3.6 (0.5-60) BU/ml and disappeared by 665 (282-1140) days, suggesting that careful monitoring of F VIII inhibitors is required in the treatment of hemophilia A.

Autoantibodies↗
PubMed1996

Pathophysiology of oligodendroglial excitotoxicity.

Oligodendrocyte-like cells (OLD) derived from the rat oligodendroglial precursor line, CG-4, express Ca(2+)-permeable non-methyl-D-aspartate glutamate receptor channels (GluR). Exposure to kainate, an L-glutamate analogue, markedly elevates OLC Ca2+ influx and cytosolic [Ca2+], and results in damage to both OLC plasma membrane and OLC nuclear DNA. Two observations indicate that kainate-induced OLC internucleosomal DNA nicking is not simply a delayed consequence of cell necrosis: 1) there is no temporal lag between onset of plasma membrane injury and of DNA nicking; and 2) aurintricarboxylic acid, an endonuclease inhibitor, blocks kainate-induced damage to the plasma membrane. N-acetyl-L-cysteine also inhibits OLC kainate injury, suggesting that reactive oxygen species participate in OLC excitotoxicity. Kainate-induced OLC Ca2+ influx and excitotoxicity are blocked by alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionate (AMPA), indicating that these kainate effects are mediated by AMPA-GluR. AMPA and L-glutamate fail to elicit OLC damage unless cyclothiazide, an AMPA-GluR desensitization blocker, is present. OLC express both the "flip" and "flop" forms of GluR2, GluR3, and GluR4 mRNAs, but neither flip nor flop GluR1 mRNA. These data, together with the restriction of the desensitization-blocking activity of cyclothiazide to GluR containing flip-encoded GluR subunits, and the sharply diminished Ca2+ permeability of GluR containing edited GluR2, suggest OLC excitotoxicity is mediated by AMPA-GluR that contain flip GluR3 and/or flip GluR4 protein subunits, but neither flip nor flop GluR2 protein subunits. Rapid desensitization of these GluR is likely to be important in protecting cells of the oligodendroglial lineage from excitotoxicity.

Acetylcysteine↗
PubMed1996

Role and initiation mechanism of the interaction of glycoprotein Ib with surface-immobilized von Willebrand factor in a solid-phase platelet cohesion process.

To know the role and initiation mechanism of the interaction of glycoprotein (GP) Ib with surface-immobilized von Willebrand factor (vWF), we examined the effect of shear stress levels on platelet binding to vWF-coated plates using a cone-and-plate type viscometer capable of loading various levels of shear stress. The extent of platelet binding to immobilized vWF reached a plateau at the shortest period tested (20 seconds) under high shear stress (90 dyne/cm2), whereas 9 to 12 minutes was necessary for saturable platelet binding under static conditions. This shear effect, which was found to be dependent on the vWF-GP Ib interaction, was observed even under the lowest shear stress (1.5 dyne/cm2) examined. In contrast with the high shear effect previously reported to initiate the interaction of GP Ib with soluble vWF, these results indicate that relatively low levels of shear stress can promote the interaction of GP Ib with surface-immobilized vWF. This effect of shear stress was observed regardless of the manner in which vWF was immobilized, suggesting that immobilization itself and not, as previously hypothesized, a conformational change in vWF induced by direct adsorption to the surface is responsible for the enhanced GPIb binding. Thus, the present findings suggest that the vWF-GP Ib interaction contributes optimally to rapid platelet cohesion on a thrombogenic surface when vWF is in a static state and when platelets are moved by an appropriate rheological force such as low shear stress.

Humans↗
PubMed1996

Expression of N-methyl-D-aspartate (NMDA) and non-NMDA glutamate receptor genes in neuroblastoma, medulloblastoma, and other cells lines.

We evaluated expression of N-methyl-D-aspartate (NMDA) and non-NMDA glutamate receptor (GluR) genes by reverse transcriptase-polymerase chain reaction (RT-PCR) and Southern blotting in nine established cell lines: rat CG-4 (oligodendroglial lineage) and RINm5F insulinoma cells; human CHP134, SMS-KCNR, SKNSH, and Nb69 neuroblastoma cells; and human D384Med, D425Med, and D458Med medulloblastoma cells. CG-4 expressed mRNAs encoding GluR2-7, KA-1, and KA-2 non-NMDA GluR (Yoshioka et al.: J Neurochem 64:2442-2448, 1995) and NR1 (NMDAR1) and NR2D NMDA GluR. After differentiation to oligodendrocyte-like cells, CG-4 also expressed NR2B mRNA. Rat insulinoma cells expressed GluR5 and KA-2 non-NMDA and NR1 and NR2D NMDA GluR mRNAs. The four human neuroblastoma lines all expressed mRNAs encoding GluR2-4, 6, 7 and KA-1 non-NMDA and NR1 NMDA GluR, and the three human medulloblastoma cell lines all expressed mRNAs encoding GluR1, 6 and KA-1, but none of the NMDA GluRs. Whereas CG-4 is susceptible to kainate excitotoxicity, treatment of insulinoma, neuroblastoma, and medulloblastoma lines with L-glutamate, kainate, alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA), or NMDA failed to cause cell damage or to augment 45Ca2+ influx. Thus, despite expressing a variety of non-NMDA and NMDA GluR genes, the human neuroblastoma and medulloblastoma and rat insulinoma lines failed to assemble Ca(2+)-permeable NMDA or non-NMDA GluR channels. This failure confers protection against excitotoxicity and may contribute to progression of tumors of these types.

Animals↗