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Hidehiko Saito

Publications and source records attributed to Hidehiko Saito.

At least 19 recordsLinked to original sources
PubMed2006

Molecular genetic analysis of a variant Bernard-Soulier syndrome due to compound heterozygosity for two novel glycoprotein Ibbeta mutations.

Bernard-Soulier syndrome (BSS) is a rare bleeding disorder characterized by giant platelets, thrombocytopenia, and prolonged bleeding time. It is caused by abnormalities in the glycoprotein (GP) Ib/IX/V complex, the receptor for von Willebrand factor (vWF). Most cases of BSS described so far involve quantitative rather than qualitative defects in the complex. In this study, we investigated the effects of two naturally occurring mutations in the GPIbbeta gene, C122S and 443delG, on the expression of the GPIb/IX complex identified in a variant type of BSS in which the platelets had severely reduced GPIbalpha ( approximately 10%) and less markedly reduced GPIbbeta and GPIX ( approximately 20%) expression. Immunoblot analysis showed the absence of non-reduced GPIb (GPIbalpha/GPIbbeta) in the patient's platelets. Transient transfection experiments in 293T cells revealed the expression of GPIbbeta Ser122 polypeptide and absence of GPIbbeta 443delG polypeptide. Although no disulfide-linked association was observed between GPIbbeta Ser122 and GPIbalpha, GPIbbeta Ser122 was non-covalently associated with both GPIbalpha and GPIX subunits on the cell surface when cotransfected with wild-type GPIbalpha and GPIX. Chinese hamster ovary cells stably expressing GPIbalpha/Ibbeta Ser122/IX had the ability to bind soluble vWF and to aggregate in the presence of ristocetin. These results suggest that despite disruption of the disulfide linkage between GPIbalpha and GPIbbeta, GPIb/IX is formed, but its stability may be impaired, resulting in low levels of the complex on the platelet membranes.

Amino Acid Sequence↗
PubMed2006

Disseminated intravascular coagulation in acute leukemia: clinical and laboratory features at presentation.

BACKGROUND: Although there are two major scoring systems for the clinical diagnosis of disseminated intravascular coagulation (DIC), the validity of these systems for leukemia-associated DIC remains to be confirmed. METHODS: By analyzing 125 newly diagnosed acute leukemia patients, we investigated clinical and laboratory features of leukemia-associated DIC, and determined the validity of the two established criteria. RESULTS: A total of 36 patients (29%) were diagnosed with DIC according to expert opinion, a method regarded as the de facto gold standard. Leukemia-associated DIC is characterized by rare manifestation of organ failure because of thrombosis and no relevance of the platelet count for the diagnosis. The results of receiver operating characteristics analysis favored fibrin degradation product (FDP) rather than D-dimer as the fibrin-related marker test. Although prothrombin time, plasma fibrinogen, and serum FDP levels were significantly different for patients with and without DIC, multivariate analysis identified FDP levels to be the only factor associated with DIC diagnosis. The cut-off level of 15 microg/mL for FDP was found to be the most effective to differentiate DIC from non-DIC, resulting in diagnostic sensitivity and specificity of 92% and 96%, respectively. The diagnostic results for our patients produced with this FDP-based system were at least comparable with or superior to those obtained with the two currently available scoring systems. CONCLUSIONS: Our findings suggest that an FDP-based criterion may be applicable for the diagnosis of leukemia-associated DIC. Although it appears to be simple and practicable enough for clinical use, prospective validation of this criterion is needed.

Acute Disease↗
PubMed2006

Aberrant DNA demethylation in promoter region and aberrant expression of mRNA of PAX4 gene in hematologic malignancies.

The PAX4 gene, a member of the paired box (PAX) gene family, is thought to be involved in regulating the fate of beta-cells in the mammalian pancreas. We observed the aberrant expression of PAX4 mRNA in 10 of 15 hematologic cell lines analyzed by RT-PCR. The restoration of PAX4 gene expression after treatment with the demethylating agent 5-aza-2'-deoxycitidine, as well as bisulfite sequencing analysis, indicated that gene overexpression was caused by DNA demethylation at the promoter region. Such DNA demethylation also was observed in primary lymphoma (20 out of 45 patients) on combined bisulfite restriction assay (COBRA). Forced expression of the PAX4 gene in the HEK293 and SHSY/610 cell lines conferred positive effects on cell growth. This profile of PAX4 thus corresponds to that of a candidate oncogene in hematologic malignancies.

Azacitidine↗
PubMed2006

Novel heterozygous missense mutation in the second leucine rich repeat of GPIbalpha affects GPIb/IX/V expression and results in macrothrombocytopenia in a patient initially misdiagnosed with idiopathic thrombocytopenic purpura.

Recent studies have shown that heterozygous carriers of the bleeding disorder Bernard-Soulier syndrome are occasionally identified as isolated case of giant platelet disorder/macrothrombocytopenia or misdiagnosed with idiopathic thrombocytopenic purpura (ITP). We describe here a patient with congenital macrothrombocytopenia who had been diagnosed with ITP. On peripheral blood smears, platelet diameter was approximately 30% larger than normal controls. In the patient's platelets, the expression level of the GPIbIX complex was slightly decreased (70-80% of normal control). Densitometric analysis of immunoblots showed GPIbalpha to be approximately 52% of normal. DNA sequencing analysis revealed a novel heterozygous missense mutation in the GPIbalpha gene that converts Tyr to Asp at residue 54 (Y54D) in the second leucine-rich repeat. Mutant GPIbalpha protein was not detected in the patient's platelets. Transient transfection studies demonstrated that mutant GPIbalpha affects complex expression. These findings suggest that null expression of the mutant GPIbalpha causes decreased density of the complex and results in macrothrombocytopenia.

Adult↗
PubMed2006

High titer of ADAMTS13 inhibitor associated with thrombotic microangiopathy of the gut and skeletal muscle after allogeneic hematopoietic stem cell transplantation.

Transplantation-associated thrombotic microangiopathy (TMA) is one of the main complications after hematopoietic stem cell transplantation (HSCT). At the time of onset of gut TMA, a patient developed a high titer of an inhibitor of the non-immunoglobulin G type to ADAMTS13, which physiologically hydrolyzes von Willebrand factor to control spontaneous intravascular thrombus formation. The patient developed symptoms of myositis, a disorder that has occasionally been reported to manifest after HSCT and to resemble some idiopathic autoimmune diseases. However, a muscle biopsy specimen presented pathologic findings of TMA, including microvascular platelet thrombus formation, without inflammatory lymphocyte infiltration. ADAMTS13 activities returned to normal after steroid treatment, and the improvement of TMA symptoms followed. This patient appears to represent a rare case of post-HSCT TMA associated with the development of an ADAMTS13 inhibitor.

ADAM Proteins↗
PubMed2006

Classic polyarteritis nodosa presenting rare clinical manifestations in a patient with hemophilia A.

A 35-year-old patient with hemophilia A presented with rapidly progressive polyarteritis nodosa (PAN). He had been infected with hepatitis B virus (HBV) by repeated transfusion and was positive for hepatitis B surface antigen but negative for hepatitis B surface antibody. The patient presented symptoms of acute epididymitis followed by emergency admission because of acute appendicitis. On day 7 of admission, he complained of severe back pain, and computerized tomography (CT) showed massive perirenal hematoma. On day 49, mild monoplegia in the left arm suddenly developed, and CT and magnetic resonance imaging revealed multiple cerebral infarctions. Factor VIII replacement therapy was attenuated; however, cerebral infarction was progressive and extended throughout the cerebral hemispheres. He was diagnosed with classic polyarteritis nodosa (cPAN), and pulse methylprednisolone was continued. The patient died of supratentorial herniation, and autopsy revealed that vasculitis associated with intimal thickening was present in the liver, pancreas, intestine, kidneys, and larger-sized cerebral arteries. The development of cPAN appeared to have originated from chronic HBV infection, and this is the first report of cPAN in hemophilia patients. Concomitant hemorrhagic and thrombotic manifestations of cPAN are hardly treatable in patients with coagulation disorders, and the current case may represent a rare transfusion-related complication in hemophilia patients.

Adult↗
PubMed2006

Recurrent intramural hematoma of the small intestine in a severe hemophilia A patient with a high titer of factor VIII inhibitor: a case report and review of the literature.

A 17-year-old man with severe hemophilia A (factor VIII <1%) developed intermittent left upper quadrant pain. He had a high titer of factor VIII inhibitor (1024 Bethesda units/mL) and was diagnosed with intramural hematoma of the jejunum. He was managed conservatively with activated prothrombin complex concentrate (APCC), resulting in the resolution of symptoms. He developed recurrent intramural hematoma of the small intestine over the next 54 months, and was successfully treated with APCC. This case highlights a rare clinical manifestation in hemophilia patients, and also indicates the effectiveness of APCC instead of exploratory surgery for intramural hematoma. Cases of intramural hematoma of the gastrointestinal tract among hemophilia patients are also reviewed.

Adolescent↗
PubMed2005

Identification of amino acid residues essential for heparin binding by the A1 domain of human von Willebrand factor.

Platelet adhesion is mediated by von Willebrand factor (VWF) that binds platelet glycoprotein Ib (GPIb). Previous observations suggested that heparin competitively inhibits the binding of VWF to GPIb and may down-regulate platelet adhesion. We performed charged-to-alanine scanning mutagenesis of domain A1 and studied dose-dependent binding to heparin-Sepharose beads. Mutations at Lys1362 and Arg1395, at which the GPIb binding was markedly decreased, showed 41% and 42% binding, respectively. Clustered mutations in the segments 1332KDRKR1336 and 1405KKKK1408, which have been proposed as heparin binding sequences, showed 72% and 52% binding, respectively. However, single alanine substitutions within these clusters showed normal binding. Our findings suggest that heparin may inhibit the binding of VWF to GPIb by interacting with GPIb binding and interpret why some hemorrhagic complications of heparin therapy are not predictable based on techniques for monitoring the conventional anticoagulant effects of heparin.

Amino Acid Substitution↗
PubMed2005

Congenital macrothrombocytopenias.

Congenital macrothrombocytopenias comprise a heterogeneous group of rare disorders, characterized by abnormal giant platelets, thrombocytopenia and bleeding tendency with variable severity. Many of these disorders share common clinical and laboratory features, making accurate diagnosis difficult and patients are often misdiagnosed with and treated for idiopathic thrombocytopenic purpura. Recent progress in the elucidation of underlying defects and further developments of specific diagnostic techniques for several congenital macrothrombocytopenias have renewed our approach to the classification and the diagnosis of the disease. This review summarizes the current knowledge on the clinical and laboratory features of common congenital macrothrombocytopenias and discusses how that knowledge aids in making a proper diagnosis.

Blood Platelets↗
PubMed2005

Transcriptional regulation of FKLF-2 (KLF13) gene in erythroid cells.

FKLF-2 (KLF13) was cloned from fetal globin-expressing tissues and has been shown to be abundantly expressed in erythroid cells. In this study we examined the transcriptional regulation of the KLF13 gene. A 5.5 kb 5' flanking region cloned from mouse erythroleukemia (MEL) cell genomic DNA showed that major cis regulatory activities exist in the 550 bp sequence to the unique transcription start site, and that the promoter is more active in K562 cells than in COS-7 cells. The promoter was trans-activated by co-expressed GATA-1 through the sequence containing two CCAAT motifs, suggesting that GATA-1 is involved in the abundant expression of KLF13 mRNA in the erythroid tissue. Dual action, i.e. activating effect in COS-7 and repressive effect in K562 cell, was observed on its own promoter, suggesting a feedback mechanism for the transcriptional control of the KLF13 gene in the erythroid environment. These findings provide an insight on the mechanism of inducible mRNA expression of the KLF13 gene in erythroid cells.

Animals↗
PubMed2005

Leukemic relapse in the central nervous system after allogeneic stem cell transplantation with complete remission in the bone marrow and donor-type chimerism: report of two cases.

We studied two cases with leukemia that relapsed in the central nervous system (CNS) after allogeneic stem cell transplantation. One patient underwent peripheral blood stem cell transplantation (SCT) from a related, yet haplotype-mismatched, donor for chronic myelomonocytic leukemia. She was kept in complete remission (CR) in the bone marrow (BM) for 7 months, until relapse in the cerebrospinal fluid (CSF) was evident. In the other patient, with acute lymphoblastic leukemia, systemic relapse occurred when he was still on immunosuppression 6 months after SCT from an unrelated donor. After induction chemotherapy following cessation of immunosuppression, the BM examination proved CR. During consolidation chemotherapy, however, he developed leukemic dissemination in the CSF, despite the fact that the BM was in CR. Chimerism status in the BM mononuclear cells and fractionated peripheral blood (PB) cells (granulocytes, T-lymphocytes, and the others) was assessed by short tandem repeat analysis. In both patients, the BM cells and all the fractions of the PB cells proved donor-type chimeras. These results seem to suggest that the graft-versus-leukemia effects might not be as effective in the CNS as in the BM, even when complete T-lymphoid chimerism is achieved.

Adult↗
PubMed2005

First description of somatic mosaicism in MYH9 disorders.

MYH9 disorders are characterized by giant platelets, thrombocytopenia, and Dohle body-like cytoplasmic granulocyte inclusion bodies that result from mutations in MYH9, which encodes non-muscle myosin heavy chain-A (NMMHCA). These disorders are known to be transmitted in an autosomal dominant manner, although about 20% of cases are considered to be sporadic. We report here the first case of a MYH9 disorder because of somatic mosaicism. The patient was the father of a male with typical May-Hegglin anomaly. The father had normal platelet counts, however, both normal-sized and giant platelets were observed on his peripheral blood smears. In addition, 14% of neutrophils contained inclusion bodies and the rest showed a normal morphology. Quantitative fluorescent polymerase chain reaction analysis showed that only 6% of DNA from peripheral blood leucocytes harboured the mutation. The mosaicism was demonstrated at a similar rate in different tissues, buccal mucosa cells and hair bulb cells, implying that the mutation had occurred before gastrulation. Mosaicism might account for some de novo mutations in MYH9 disorders.

Base Sequence↗
PubMed2005

Detection of unique neutrophil non-muscle myosin heavy chain-A localization by immunofluorescence analysis in MYH9 disorder presented with macrothrombocytopenia without leukocyte inclusions and deafness.

MYH9 disorders are autosomal-dominant macrothrombocytopenias with leukocyte inclusions caused by mutations in the MYH9 gene, which encodes the non-muscle myosin heavy chain-A (NMMHCA). We report a patient with an MYH9 disorder who presented with macrothrombocytopenia without leukocyte inclusions and severe bilateral sensory deafness. Conventional May-Grunwald-Giemsa staining failed to detect granulocyte cytoplasmic inclusions, whereas immunofluorescence analysis clearly demonstrated abnormal neutrophil NMMHCA localization. Genetic analyses revealed a novel heterozygous 18 base deletion in MYH9, leading to a six-amino acid in-frame deletion (N76_S81del) in NMMHCA. These results further support the usefulness of immunofluorescence analysis in differential diagnosis of MYH9 disorders.

Amino Acid Sequence↗
PubMed2005

Long-term outcomes for unselected patients with acute myeloid leukemia categorized according to the World Health Organization classification: a single-center experience.

The actual utility of a new classification system of acute myeloid leukemia (AML) recently introduced by the World Health Organization (WHO) has not been thoroughly investigated yet. In this study, we evaluated long-term outcomes of unselected AML patients categorized according to the new WHO classification. Between 1990 and 2002, 109 adult AML cases were referred to our hospital. For the entire population, the median survival duration was 1.2 yr with a 5-yr survival rate of 31%. AML with recurrent genetic abnormalities accounted for 26%, AML with multilineage dysplasia for 29%, therapy-related AML for 13%, and AML not otherwise categorized for 32% of classifiable cases. Among the four groups, a significant difference was observed in terms of overall survival (P < 0.0001). Univariate analysis showed that six variables affected survival: cytogenetic risk, age, multilineage dysplasia, prior chemo/radiotherapy, type of treatment (intensive or palliative), and transplantation. However, in multivariate analysis no adverse prognostic impact of multilineage dysplasia and prior chemo/radiotherapy was detected (P = 0.4979 and 0.8702), whereas cytogenetic risk and patient age maintained their prognostic value (P = 0.0005 and 0.0100). These results indicate that outcomes for AML patients appear to be distinguished on the basis of the WHO classification, but the prognostic significance of multilineage dysplasia and prior therapy is lost after adjusting for cytogenetic risk and age. Our findings suggest that the WHO classification may be strengthened by greater emphasis on genetic/cytogenetic information.

Adolescent↗
PubMed2005

Long-term results of a multicenter randomized, comparative trial of modified CHOP versus THP-COP versus THP-COPE regimens in elderly patients with non-Hodgkin's lymphoma.

In treating elderly non-Hodgkin's lymphoma (NHL) patients, it is particularly important to use drugs that have a low incidence of adverse events and high efficacy. In this multicenter study, THP (pirarubicin)-COP (cyclophosphamide, vincristine, and prednisolone) was compared to two thirds dosage of full CHOP (cyclophosphamide, doxorubicin, vincristine, and prednisolone) regimen with regard to both adverse events and efficacy. For a third group, etoposide (E) was added to the THP-COP regimen (THP-COPE) in order to achieve high dose-intensity. Subjects were 486 previously untreated patients, aged 65 or older (range, 65-92 years; median, 74 years), with NHL. Subjects were randomly assigned to receive THP-COP, two thirds CHOP, or THP-COPE. Four hundred and forty-three patients were assessed for response and followed for 8 years after the last subject registered. The complete remission rates for the THP-COP, CHOP, and THP-COPE groups were 42.5%, 41.4%, and 48.0%, respectively. There was no difference in overall survival or progression-free survival among these 3 groups. In aggressive lymphoma, there was also no difference in complete response (CR) rate (45.3% in THP-COP, 44.9% in CHOP, 48.0% in THP-COPE), overall survival, and progression-free survival among these groups. The 5- and 8-year survival rates for all patients were 29.4% and 18.7%, respectively. The 5- and 8-year survival rates for patients with aggressive lymphoma were 27.4% and 17.4%, respectively. Although long-term survival for patients with aggressive lymphoma on our regimens was not worse compared to previous reports, the CR rate was lower. Because severe adverse events were not observed, higher dose chemotherapy may be directed to achieve better CR rates. In patients with T-cell-type lymphoma, the CR rate was greater after treatment with THP-COP (51.4%) or THP-COPE (57.7%) compared to treatment with CHOP (19.4%). Pirarubicin may be more useful for T-cell lymphoma than doxorubicin. Because adverse cardiac events were reported only in CHOP, adverse cardiac events might be low in the THP group.

Aged↗