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Ikuo Miura

Publications and source records attributed to Ikuo Miura.

At least 19 recordsLinked to original sources
PubMed2005

Enamelin (Enam) is essential for amelogenesis: ENU-induced mouse mutants as models for different clinical subtypes of human amelogenesis imperfecta (AI).

Amelogenesis imperfecta (AI) is a group of commonly inherited defects of dental enamel formation, which exhibits marked genetic and clinical heterogeneity. The genetic basis of this heterogeneity is still poorly understood. Enamelin, the affected gene product in one form of AI (AIH2), is an extracellular matrix protein that is one of the components of enamel. We isolated three ENU-induced dominant mouse mutations, M100395, M100514 and M100521, which caused AI-like phenotypes in the incisors and molars of the affected individuals. Linkage analyses mapped each of the three mutations to a region of chromosome 5 that contained the genes encoding enamelin (Enam) and ameloblastin (Ambn). Sequence analysis revealed that each mutation was a single-base substitution in Enam. M100395 (Enam(Rgsc395)) and M100514 (Enam(Rgsc514)) were putative missense mutations that caused S to I and E to G substitutions at positions 55 and 57 of the translated protein, respectively. Enam(Rgsc395) and Enam(Rgsc514) heterozygotes showed severe breakage of the enamel surface, a phenotype that resembled local hypoplastic AI. The M100521 mutation (Enam(Rgsc521)) was a T to A substitution at the splicing donor site in intron 4. This mutation resulted in a frameshift that gave rise to a premature stop codon. The transcript of the Enam(Rgsc521) mutant allele was degraded, indicating that Enam(Rgsc521) is a loss-of-function mutation. Enam(Rgsc521) heterozygotes showed a hypomaturation-type AI phenotype in the incisors, possibly due to haploinsufficiency of Enam. Enam(Rgsc521) homozygotes showed complete loss of enamel on the incisors and the molars. Thus, we report here that the Enam gene is essential for amelogenesis, and that mice with different point mutations at Enam may provide good animal models to study the different clinical subtypes of AI.

Amelogenesis↗
PubMed2005

Primary effusion lymphoma of the pericardial cavity carrying t(1;22)(q21;q11) and t(14;17)(q32;q23).

We report a case of primary effusion lymphoma (PEL) in a 75-year-old woman without human immunodeficiency virus or hepatitis C virus, which presented as fever, chest pain, and pericardial effusion. The lymphoma cells were positive for CD20 and CD79a, and were negative for CD3 and CD10. Genomic human herpes virus 8 (HHV-8) and Epstein-Barr virus were not detected in the lymphoma cells. Cytogenetic analysis showed complex abnormalities by the G-banding technique, and spectral karyotyping (SKY) analysis provided more detailed characterization of the chromosomal aberrations, including t(1;22)(q21;q11) and t(14;17)(q32;q23). We did not detect C-MYC gene rearrangement or BCL-2 expression. She was treated successfully with six courses of the CHOP regimen. The present case demonstrated a rare category of PEL that is not associated with HHV-8 or C-MYC gene rearrangement. In addition, SKY analysis disclosed cryptic chromosomal abnormalities involving 1q21 and 17q23.

Aged↗
PubMed2005

Cytogenetic features of de novo CD5-positive diffuse large B-cell lymphoma: chromosome aberrations affecting 8p21 and 11q13 constitute major subgroups with different overall survival.

De novo CD5-positive diffuse large B-cell lymphoma (CD5(+)DLBCL) is regarded as a different clinicopathological entity from CD5-negative DLBCL (CD5(-)DLBCL) and mantle cell lymphoma (MCL). Because only a few published cytogenetic studies of de novo CD5(+)DLBCL are available, we investigated chromosomal changes in 23 Japanese patients who had de novo CD5(+)DLBCL. A characteristic of cytogenetic abnormalities in de novo CD5(+)DLBCL was a high incidence of chromosomal aberrations affecting 8p21 and 11q13. Major chromosomal breakpoints were concentrated at 8p21, 11q13, and 3q27. Patients with 8p21 aberrations showed aggressive clinical features, including advanced stage of disease, elevated serum LDH level, poor performance status, and an inferior survival curve compared with patients who had 11q13 changes (P = .043). Chromosomal abnormalities of both 8p21 and 11q13 were not observed in the same patient, and each abnormality showed different chromosomal gains and losses. These results indicate that de novo CD5(+)DLBCL may occur in previously unidentified subgroups that differ in their chromosomal abnormalities. The conflicting results of previous studies on prognosis may thus be explained in part by the differences in chromosomal changes.

Adult↗
PubMed2005

Origins of mouse inbred strains deduced from whole-genome scanning by polymorphic microsatellite loci.

Microsatellite loci are uniformly distributed at approximately 100-kbp intervals on all chromosomes except the chromosome Y, and genetic information about more than 9000 loci and high-throughput polymorphism analysis are now available. Taking advantage of these properties, we carried out whole-genome scanning using eight common inbred strains (CIS) of laboratory mice, including A/J, C57BL/6J, CBA/J, DBA/2J, SM/J, SWR/J, NC/Nga, and 129/SvJ, and eight wild-derived inbred strains (WIS), BGL2/Ms, CAST/Ei, JF1/Ms, MSM/Ms, NJL/Ms, PGN2/Ms, SK/CamEi, and SWN/Ms. We selected and located 1226 informative loci at 1.2-cM average intervals on all of the chromosomes of the 16 strains and compared the polymorphisms of the eight CIS with those from the eight WIS as subspecies representatives. More than 50% of the loci can be identified as WIS (therefore, subspecies-specific) alleles in the CIS genomes. We also discovered that the CIS chromosomes form a mosaic structure with an average ratio of domesticus to non-domesticus alleles of 3:1. Furthermore, the domesticus alleles were present much more frequently on the CIS chromosome X than on their autosomes, suggesting that successive backcrossing of non-domesticus stocks to domesticus stocks had been undergone at the beginning of CIS history.

Animals↗
PubMed2004

Molecular-cytogenetic characterization of non-Hodgkin's lymphoma with double and cryptic translocations of the immunoglobulin heavy chain gene.

The present study aimed to characterize the clinical and molecular-cytogenetic features of non-Hodgkin's lymphoma (NHL) with double translocation of the immunoglobulin heavy chain (IGH) gene. G-banding analysis, fluorescence in situ hybridization (FISH) with the IGH (Cgamma and VH) and oncogene (c-MYC, BCL1, BCL2, and BCL6) probes, and long-distance polymerase chain reaction (LD-PCR) were performed on 6 patients with B-cell lymphoma, one with angioimmunoblastic T-cell lymphoma, and one with acute lymphoblastic leukemia (ALL) with B-cell phenotype. G-banding analysis detected two different 14q32 translocations, t(14,18) and add (14)(q32) in a patient with ALL. Two distinct partners of double IGH translocation identified by FISH were as follows: c-MYC + BCL2 in 3 patients, c-MYC + BCL1 in 2, c-MYC + BCL6 in one, BCL2 + 9q22 in one, and 1q21 + 6q27 in one. Colocalization of BCL1 and c-MYC probes was demonstrated in a patient with mantle cell lymphoma. LD-PCR detected c-MYC/Cmu, c-MYC/Calpha and BCL6/Cmu, and c-MYC/Calpha fusion in each one patient. Seven of 8 patients showed high serum LDH. Central nervous system and leukemic involvement was observed in 5 and 6 patients, respectively. Median survival time of patients with c-MYC/IGH translocation was 9 months. The results defined a clinical subset of B-cell lymphoma/leukemia showing extremely poor prognosis. C-MYC/IGH translocation is possibly an evolutionary alteration following the primary IGH translocation with BCL1, BCL2, or BCL6. Furthermore, FISH identified one novel (9q22) and one cryptic chromosomal breakpoints (6q27) involved in IGH translocation.

Adult↗
PubMed2004

Intravascular large B-cell lymphoma presenting with mass lesions in the central nervous system: a report of five cases.

We have encountered five cases of intravascular large B-cell lymphoma (IVL) presenting with central nervous system (CNS) mass lesions during their clinical course. The age of the patients ranged from 50 to 74 years and three patients were male. All of these cases histopathologically showed typical intravascular localization of the neoplastic cells in the initial biopsy specimens obtained from sites other than the CNS. Despite multiagent chemotherapy, patients suffered from single or multiple CNS mass lesions 5-44 months after the initial diagnosis of IVL, except for one case in which IVL and the CNS mass lesion were diagnosed at the same time. The subsequent biopsy and autopsy specimens obtained from the CNS mass lesions revealed diffuse infiltration of the tumor cells with perivascular spreading, but minimal or no intravascular components. Immunohistochemical analysis of intravascular tumor cells and CNS mass lesions revealed expression of CD20, CD79a, bcl-2 and negative for CD3e and Epstein-Barr virus encoded RNA. The overall features of the CNS mass lesions were very similar to or indistinguishable from those of the primary CNS lymphomas. This implies that CNS mass lesions in the IVL cases can be correctly diagnosed only by careful attention to clinical and pathological findings. Moreover, there is the possibility that some cases previously diagnosed as primary CNS lymphomas may have include IVL cases. Further investigation is needed to explore this unusual phenomenon.

Aged↗
PubMed2004

Case of B-cell lymphoma with rearrangement of the BCL1, BCL2, BCL6, and c-MYC genes.

We managed a peculiar case of lymphoma showing immunohistochemical overexpression of cyclin D1. At initial examination the patient had meningeal lymphomatosis and general lymphadenopathy. Histologic examination of biopsy specimens of inguinal lymph nodes showed tumor cells and vague nodular growth resembling lymphoblasts. The results of flow cytometric analysis were positive for CD10, CD20, CD103, and immunoglobulin G (IgG) and Ig kappa and were negative for CD5, CD23, and terminal deoxynucleotidyl transferase activity. Results of immunohistochemical analysis of paraffin-embedded specimens were positive for cyclin D1 and Bcl2 in the tumor cells. Sixty percent of tumor cells had positive results for MIB1/Ki67. Cytogenetic and molecular studies revealed tumor cells simultaneously had t(14;18)(q32;q21), t(11;22)(q13;q11), t(8;14)(q24;q32), and t(3;14)(q27;q32) with the rearrangement of BCL1, BCL2, BCL6, and c-MYC genes. Lymphadenopathy showed a quick and complete response to doxorubicin-containing systemic chemotherapy with rituximab, but the central nervous system disease progressed and killed the patient.

Aged↗
PubMed2004

Monitoring the expression profiles of doxorubicin-resistant K562 human leukemia cells by serial analysis of gene expression.

We examined the expression profiles of doxorubicin-resistant K562 cells by serial analysis of gene expression (SAGE) to identify novel and/or partially characterized genes that might be related to drug resistance in human leukemia. SAGE complementary DNA (cDNA) libraries were constructed from K562 and doxorubicin-resistant K562 (K562/ADM) cells, and concatamer sequences were analyzed with SAGE 2000 software. We used 9792 tags in the identification of 1076 different transcripts, 296 of which were similarly expressed in K562 and K562/ADM cells. There were 343 genes more actively expressed in K562/ADM than in parental K562 cells and 437 genes expressed less often in K562/ADM cells. K562/ADM cells showed increased expression of well-known genes, including the genes for spectrin beta, eukaryotic translation initiation factor 1A (EIF1A), RAD23 homolog B, laminin receptor 1, and polyA-, RAN-, and PAI-1 messenger RNA-binding proteins. K562/ADM cells showed decreased expression of the genes for fatty acid desaturase 1 (FADS1), hemoglobin epsilon 1, N-myristoyltransferase 1, hemoglobin alpha 2, NADH dehydrogenase Fe-S protein 6, heat shock 90-kDa protein, and karyopherin beta 1. Quantitative reverse transcription-polymerase chain reaction analysis confirmed the increased expression of EIF1A and the decreased expression of FADS1 in K562/ADM cells. Prior to this investigation, such differences in the expression of these genes in doxorubicin-resistant leukemia cells were unknown. Although we do not provide any evidence in the present report for the potential roles of these genes in drug resistance, SAGE may provide a perspective into our understanding of drug resistance in human leukemia that is different from that provided by cDNA microarray analysis.

Delta-5 Fatty Acid Desaturase↗
PubMed2004

Contribution of Complementarity-Determining Region 3 of the T-Cell Receptor Vδ2 Chain to the Recognition of Aminobisphosphonates by Human γδ T-Cells.

Human gammadelta T-lymphocytes expressing Vgamma2Vdelta2 T-cell receptors (TCRs) can be stimulated by aminobisphosphonates and can kill certain tumor cells. Although germline-encoded lysine residues on the Jgamma1.2 segment have been demonstrated to be essential for the recognition of nonpeptide antigens by human gammadelta T-cells, the role of the junctional sequences of the TCR delta chain in the recognition of aminobisphosphonates by Vgamma2Vdelta2+ T-cells remains unknown. We examined the structure of complementarity-determining region 3 (CDR3) of Vdelta2 chains expressed by aminobisphosphonate-stimulated human gammadelta T-cells. CDR3 size-spectratyping analysis of Vdelta2 chains revealed that risedronate did not induce a CDR3 size distribution pattern of Vdelta2 cells that was distinct from that of Vdelta2 cells cultured without risedronate. The clonality of risedronate-expanded Vdelta2 T-cells was also determined by sequencing analysis, with the result that no particular consensus sequences were observed. However, most Vdelta2 T-cells freshly isolated from peripheral blood carried a distinctive junctional motif consisting of a hydrophobic amino acid residue (valine, leucine, or isoleucine [Val/Leu/Ile]) at conserved position 97, and this feature was not altered by risedronate stimulation. A significant proportion of Vdelta1 T-cells from the same individual had Leu at position 97, but Vdelta1 T-cells did not expand in response to risedronate. Moreover, Vdelta2 T-cells from the nonresponder against risedronate also carried a Val/Leu/Ile amino acid residue at position 97. These results suggest that the presence of a hydrophobic amino acid residue at position 97 in CDR3 of the TCR delta chain is not sufficient to account for the recognition of aminobisphosphonate by human gammadelta T-cells.

Amino Acid Sequence↗
PubMed2004

Gene expression profiling of human erythroid progenitors by micro-serial analysis of gene expression.

We compared the expression profiles of highly purified human CD34+ cells and erythroid progenitor cells by micro-serial analysis of gene expression (microSAGE). Human CD34+ cells were purified from granulocyte colony-stimulating factor-mobilized blood stem cells, and erythroid progenitors were obtained by cultivating these cells in the presence of stem cell factor, interleukin 3, and erythropoietin. Our 10,202 SAGE tags allowed us to identify 1354 different transcripts appearing more than once. Erythroid progenitor cells showed increased expression of LRBA, EEF1A1, HSPCA, PILRB, RANBP1, NACA, and SMURF. Overexpression of HSPCA was confirmed by real-time polymerase chain reaction analysis. MicroSAGE revealed an unexpected preferential expression of several genes in erythroid progenitor cells in addition to the known functional genes, including hemoglobins. Our results provide reference data for future studies of gene expression in various hematopoietic disorders, including myelodysplastic syndrome and leukemia.

Antigens, CD34↗
PubMed2004

Durable response but prolonged cytopenia after cladribine treatment in relapsed patients with indolent non-Hodgkin's lymphomas: results of a Japanese phase II study.

We conducted a phase II study to evaluate the efficacy and safety of cladribine (2-chlorodeoxyadenosine [2-CdA]) for patients with refractory or relapsed indolent B-cell lymphoma or mycosis fungoides. Forty-five patients were enrolled, and 43 patients, including 34 with follicular lymphoma, were eligible. 2-CdA was given by continuous intravenous infusion at a dose of 0.09 mg/kg daily for 7 consecutive days, and this schedule was repeated every 4 weeks up to a maximum of 6 cycles. The overall and complete response rates were 58.1% (25/43; 90% confidence interval, 44.5%-70.9%) and 14.0% (6/43), respectively. The disease progression-free proportions of all 43 eligible and all 25 responding patients at 2 years were 30.3% and 48.1%, respectively. Neutropenia and thrombocytopenia of grade 3 or 4 were observed in 53.3% and 37.8% of patients, respectively, with prolonged cytopenia observed in patients with increased numbers of treatment cycles. Nonhematologic toxicities of grade 3 or greater included diarrhea, arrhythmia, malaise, and gastrointestinal bleeding in 1 patient each, an increase in glutamic-pyruvic transaminase level in 2 patients, and infection in 5 patients. Two treatment-related deaths were observed. Four patients developed myelodysplastic syndrome (MDS) at 13 months to 2 years after completion of the 2-CdA treatments. 2-CdA is an active agent with acceptable toxicity for refractory or relapsed indolent lymphoma; however, prolonged myelosuppression and the potential development of MDS should be carefully monitored.

Adult↗
PubMed2004

Update of mouse microsatellite database of Japan (MMDBJ).

We updated a database of microsatellite marker polymorphisms found in inbred strains of the mouse, most of which were derived from the wild stocks of four Mus musculus subspecies, M. m. domesticus, M. m. musculus, M. m.castaneus and M. m. molossinus. The major aim of constructing this database was to establish the genetic status of these inbred strains as resources for linkage analysis and positional cloning. The inbred strains incorporated in our database are A/J, C57BL/6J, CBA/J, DBA/2J, SM/J, SWR/J, 129Sv/J, MSM/Ms, JF1/Ms, CAST/Ei, NC/Nga, BLG2/Ms, NJL/Ms, PGN2/Ms, SK/CamEi and SWN/Ms, which have not or have only been poorly incorporated in the Whitehead Institute/MIT (WI/MIT) microsatellite database. The number of polymorphic microsatellite loci incorporated in our database is over 1,000 in all strains, and the URL site for our database is located at http:// www.shigen.nig.ac.jp /mouse/mmdbj/mouse.html.

Animals↗
PubMed2004

[GVHD].

Explore the source record for details and available documents.

Antilymphocyte Serum↗
PubMed2003

Role of aromatase and androgen receptor expression in gonadal sex differentiation of ZW/ZZ-type frogs, Rana rugosa.

To elucidate the mechanisms of amphibian gonadal sex differentiation, we examined the expression of aromatase and androgen receptor (AR) mRNAs for days 17-31 after fertilization. The effects of inhibitors and sex steroid hormones were also examined. In ZZ males, expression of AR decreased after day 19, while aromatase expression was low throughout the sampling period. Males treated with 17beta-estradiol (E2) showed increasing aromatase expression after day 21, and formed ovaries. AR antagonist treatment also induced high-level aromatase expression and ovarian differentiation. In males co-treated with an aromatase inhibitor and E2, the undifferentiated gonads developed into testes despite high-level aromatase expression. Males treated with androgen and E2 before and during an estrogen sensitive period, respectively, also formed testes. In ZW females, AR expression persisted at a low-level, while aromatase expression increased after day 18. Short-term treatment with an aromatase inhibitor was ineffective in preventing ovarian differentiation, whereas long-term treatment resulted in testes developing from ovarian structure. Compared with the ZZ males and ZW females, WW females did not exhibit detectable expression of AR, suggesting that the active AR gene(s) itself, or a putative gene regulating AR gene expression, is located on Z chromosomes. From the time lag of aromatase expression between ZW females and ZZ males treated with E2 and the effect of AR antagonist, it was found that in males elevated AR expression suppresses aromatase expression directly or indirectly. Consequently, endogenous androgens, accumulated by blocking estrogen biosynthesis, induced testicular differentiation. The gonadogenesis of males is dependent on sex hormone, whereas that of females has evolved to hormone-independence.

Androgen Antagonists↗
PubMed2003

A small deletion hotspot in the type II keratin gene mK6irs1/Krt2-6g on mouse chromosome 15, a candidate for causing the wavy hair of the caracul (Ca) mutation.

A new mutation has arisen in a colony of mice transgenic for human alpha-galactosidase. The mutation is independent of the transgenic insertion, autosomal dominant, and morphologically very similar to the classical wavy coat mutation, caracul (Ca), on chromosome 15. Therefore, we designated this locus the caracul Rinshoken (Ca(Rin)). Applying a positional cloning approach, we identified the mK6irs1/Krt2-6g gene as a strong candidate for Ca(Rin) because among five Ca alleles examined mutations always occurred in the highly conserved positions of the alpha-helical rod domain (1A and 2B subdomain) of this putative gene product. The most striking finding is that four independently discovered alleles, the three preexistent alleles Ca(J), Ca(9J), Ca(10J), and our allele Ca(Rin), all share one identical amino acid deletion (N 140 del) and the fifth, Ca(medJ), has an amino acid substitution (A 431 D). These findings indicate that a mutation hotspot exists in the Ca locus. Additionally, we describe a Ca mutant allele induced by ENU mutagenesis, which also possesses an amino acid substitution (L 424 W) in the mK6irs1/Krt2-6g gene. The identification of the Ca candidate gene enables us to further define the nature of the genetic pathway required for hair formation and provides an important new candidate that may be implicated in human hair and skin diseases.

Amino Acid Sequence↗
PubMed2003

[Hemolytic uremic syndrome-like episode following nonmyeloablative hematopoietic stem cell transplantation in a patient with chronic myeloid leukemia].

We report on a 61-year-old woman with chronic myeloid leukemia (CML) who developed a hemolytic uremic syndrome (HUS)-like episode following nonmyeloablative allogeneic hematopoietic stem cell transplantation. Macrohematuria, hypertension, hemolytic anemia with red cell fragmentation, thrombocytopenia, and progressive renal insufficiency were observed after thawed peripheral blood stem cell (PBSC) infusion. Although transient systemic hemolysis is known to occur during dimethylsulfoxide (DMSO)-cryopreserved stem cell infusion, HUS caused by DMSO has not been described in the literature. We speculate that one of the triggers of the HUS-like episode could have been renal microangiopathy caused by the long-term administration of interferon-alpha before the stem cell transplantation.

Cryopreservation↗