Search PubMed⌕ Search

Biomedical subjects

K Muta

Publications and source records attributed to K Muta.

At least 19 recordsLinked to original sources
PubMed2005

Reduced-intensity hematopoietic stem-cell transplantation for malignant lymphoma: a retrospective survey of 112 adult patients in Japan.

We conducted a nation-wide survey of 112 adult Japanese patients who underwent reduced-intensity stem cell transplantation (RIST) from 1999 to 2002. Underlying diseases included indolent (n=45), aggressive (n=58) and highly aggressive lymphomas (n=9). Median age of the patients was 49 years. A total of 40 patients (36%) had relapsed diseases after autologous stem cell transplantation and 36 patients (32%) had received radiotherapy. RIST regimens were fludarabine-based (n=95), low-dose total body irradiation-based (n=6) and others (n=11). Cumulative incidences of grade II-IV acute graft-versus-host disease (GVHD) and chronic GVHD were, respectively, 49 and 59%. Cumulative incidences of progression and progression-free mortality were 18 and 25%, respectively. With a median follow-up of 23.9 months, 3-year overall survival rates were 59%. A multivariate analysis identified three significant factors for progression, which are history of radiation (relative risk (RR) 3.45, confidential interval (CI) 1.12-10.0, P=0.03), central nervous system involvement (RR 6.25, CI 2.08-20.0, P=0.001) and development of GVHD (RR 0.28, CI 0.090-0.86, P=0.026). RIST may have decreased the rate of transplant-related mortality, and GVHD may have induced a graft-versus-lymphoma effect. However, whether or not these potential benefits can be directly translated into improved patient survival should be evaluated in further studies.

Adult↗
PubMed2005

Role of NF-kappa B in regulation of apoptosis of erythroid progenitor cells.

Erythropoietin (EPO) and interferon-gamma (IFN-gamma) added to human erythroid progenitor cells purified from peripheral blood (erythroid colony-forming cells; ECFC) significantly reduces apoptosis as assessed by flow cytometry (FCM) using annexin V. To clarify the role of NF-kappaB in the regulation of the apoptosis of erythroid progenitor cells, cyclosporin A (CsA), which blocks dissociation of the NF-kappaB complex, was added to serum-free cultures of ECFC. CsA induced the apoptosis of ECFCs in the presence of EPO or IFN-gamma, but at different magnitudes. In the presence of a relatively low concentration of CsA (10 microm), apoptosis was induced only in cultures with EPO. The direct involvement of NF-kappaB was then assessed by Western blotting and confocal microscopy. In the presence of EPO, NF-kappaB was abundant both in the cytoplasm and in the nucleus, and nuclear expression was diminished after adding CsA. In contrast, NF-kappaB was undetectable in the nucleus in the presence of IFN-gamma. The effect of CsA on mitochondrial function was investigated by determining the DeltaPsim and reactive oxygen species production. CsA disturbed the transmembrane potential in the presence of either EPO or IFN-gamma, although the viability of the cells was maintained in the presence of IFN-gamma plus CsA. These results indicate that IFN-gamma reduced the apoptosis of erythroid progenitor cells through a unique signaling pathway that is independent of NF-kappaB translocation, and which is not mediated by modulating mitochondrial function, whereas EPO reduced apoptosis through NF-kappaB translocation to the nucleus.

Apoptosis↗
PubMed2002

Hemophagocytic syndrome: a rare complication of allogeneic nonmyeloablative hematopoietic stem cell transplantation.

We report two cases of patients with malignant lymphoma who presented with early onset of hemophagocytic syndrome after nonmyeloablative allogeneic peripheral blood stem cell transplantation. Fever and skin eruption developed early after transplantation, and neurological symptoms preceded cytopenia and worsened progressively. Activated macrophages with hemophagocytosis were found in bone marrow of the two patients at day 15 and 56, respectively. The fact that no obvious infectious agents associated with hemophagocytic syndrome were detected, and that serum soluble interleukin-2 receptor concentrations were elevated in the early phase after transplantation, reflecting the activation of donor-derived T cells, suggests that this complication resulted from an alloimmune response.

Adult↗
PubMed2002

Prognostic value of Bcl 10 rearrangement in diffuse large B-cell lymphoma.

The role of bcl 10, a recently cloned apoptosis-associated gene, in diffuse large B-cell lymphoma (DLBL) is unknown. Here we determined the role of bcl 10 gene rearrangement on prognosis. Bcl 10 rearrangement was examined by Southern blot. Bcl 10 rearrangement was detected in 20 of 137 (14.6%) samples of DLBL. The frequency of bcl 10 rearrangement was higher in extranodal (eight of 38 cases, 21%) than in nodal (12 of 99, 12%) DLBL. The survival rate in patients with bcl 10 rearrangement tended to be better than in those with germ-line bcl 10, albeit statistically insignificant probably due to the small population sample. The superior prognosis in patients with bcl 10 rearrangement might be due to bcl 10-induced enhanced apoptosis.

Adolescent↗
PubMed2001

Receptor binding cancer antigen expressed on SiSo cells, a novel regulator of apoptosis of erythroid progenitor cells.

To better understand the control of apoptosis during erythropoiesis, this study investigated the role of a novel tumor-associated antigen, RCAS1 (receptor binding cancer antigen expressed on SiSo cells), with regard to the regulation of apoptosis of erythroid progenitor cells. Erythroid colony-forming cells (ECFCs) purified from human peripheral blood were used. Binding experiments of RCAS1 showed that ECFCs abundantly expressed receptors (RCAS1R) for RCAS1 and that the degree of binding of RCAS1 to the receptors diminished rapidly during erythroid maturation in vitro. When the soluble form of RCAS1 was added to the cultures, ECFCs underwent apoptosis, including collapse of the mitochondrial transmembrane potential, and activation of caspases 8 and 3. The addition of an anti-Fas blocking antibody or Fas-Fc failed to reduce the apoptosis induced by RCAS1, thereby indicating that effects of RCAS1 are independent of Fas activation. When binding of RCAS1 to normal bone marrow cells was analyzed, RCAS1R was evident on cells with an immature erythroid phenotype (transferrin receptor(+)/glycophorin A(-)) but not with a mature phenotype (transferrin receptor(-)/glycophorin A(+)). Histochemical staining revealed the expression of RCAS1 in the cytoplasm of bone marrow macrophages. These findings indicate that RCAS1, which is mainly produced by macrophages in hematopoietic tissue, may have a crucial role in controlling erythropoiesis by modulating apoptosis of erythroid progenitor cells via a Fas-independent mechanism.

Adenocarcinoma↗
PubMed2001

Expression of human tumor-associated antigen RCAS1 in Reed-Sternberg cells in association with Epstein-Barr virus infection: a potential mechanism of immune evasion.

RCAS1 (receptor-binding cancer antigen expressed on SiSo cells) is present in neoplastic cells, induces apoptosis of natural killer (NK)/T cells and plays a role in immune evasion. Fas ligand (FasL) is considered to have similar roles. The Epstein-Barr virus (EBV)-encoded latent membrane protein is expressed by malignant Hodgkin and Reed-Sternberg (H&RS) cells of EBV-associated Hodgkin's disease (HD) and considered to be a target of cytotoxic T lymphocytes (CTLs). However, CTL response is inadequate in HD. To determine whether RCAS1 and FasL are expressed in EBV-associated HD and participate in immune evasion, tissues of 20 EBV(-) and 15 EBV(+) HD cases were immunohistochemically stained for RCAS1, FasL and HLA classes I and II, whose deficiencies could explain CTL escape. Lymphocytes surrounding H&RS cells tended to be CD4(+) cells and rarely CD8(+), TIA-1(+) (cytotoxic marker) or NK cells. HLA class I and/or II were expressed in all EBV(+) HD cases, and RCAS1-expressing H&RS cells were found in 14/15 (93%) EBV(+) HD cases but only 8/20 (40%) EBV(-) HD cases (p < 0.05). FasL was detected in 9/15 (60%) and 7/20 (35%) EBV(+) and EBV(-) HD cases, respectively. ssDNA-positive (apoptotic) lymphocytes, surrounding H&RS cells, were rarely seen but were present in RCAS1(+) cases (20/22 cases, 91%) rather than negative cases (0/13 cases, 0%) (p < 0.005). Our findings suggest that EBV(+) H&RS cells might evade the host immune response by expressing RCAS1 rather than FasL.

Adolescent↗
PubMed2001

Wide use of skin-lightening soap may cause mercury poisoning in Kenya.

In a previous study, we speculated that some of the high mercury levels observed in head hair from a total of 14 subjects who resided around Lake Victoria, Tanzania, might be attributable to the habitual use of toilet soap containing considerable amounts of mercury (Harada et al. Sci Total Environ 1999;227:249-256). In August 1998, the current study was conducted to investigate if such mercury-containing soap was also available in the surroundings of Lake Victoria, Kenya, and if so, its toxic effects. A total of nine goldminers, 44 fishermen and their families, and 12 residents of Kisumu City, Kenya, volunteered for the study. Fourteen types of toilet soap were collected in Kisumu. Total mercury content was very significantly higher than in European-made soap (0.47-1.7%, as mercury iodide) compared with Kenya-made soap (0.41 x 10(-4)-6.2 x 10(-4)%). Indeed, all the subjects with a high hair mercury level (> 36.1 ppm) had made habitual use of European-made soap, accompanied by various symptoms, such as tremor, lassitude, vertigo, neurosthenia, and black and white blots, suggesting inorganic-mercury poisoning. On the other hand, any subject who had used soap other than the European-made soap, did not exceed a mercury level of 10 ppm in hair that is well within normal limits (Harada et al. Sci Total Environ 1999:227:249-256). The findings obtained suggest that the mercury-containing soap must be barred from circulation without delay, and that the residents' health in addition to the environmental pollution in Lake Victoria (Kenya as well as Tanzania) should be kept under close observation.

Adult↗
PubMed2001

Cloning and functional expression of a degradation-resistant novel isoform of p27Kip1.

p27(Kip1) is an inhibitor of cyclin-dependent kinases. It has been implicated as having a role in the induction of growth arrest at the G(1) phase of the cell cycle in response to anti-mitogenic signals such as cell contact and serum starvation. Proteasome-mediated degradation plays an important role in the rapid inactivation of p27(Kip1), causing quiescent cells to re-enter the cell cycle. Although the existence of a second isoform has been suggested, no such isoform was isolated. Through screening of a cDNA library derived from growth-arrested confluent porcine endothelial cells, we obtained clones for a novel isoform of p27(Kip1) in addition to the original isoform. The novel isoform differed from the original isoform at the C-terminus. The tissue-specific expression of the original and novel isoforms was demonstrated at the mRNA and protein levels. An in vitro degradation assay demonstrated this novel isoform to be resistant to proteasome-mediated destruction. The expression as a fusion protein with green fluorescent protein revealed this isoform to be targeted to the nucleus by a bipartite nuclear-localization signal with a C-terminal part different from that of the original isoform. The expression of the novel isoform caused the growth arrest of HeLa cells and an accumulation of cells in the G(0)/G(1) phase, and this effect was similar to that seen with the original isoform. The present study suggests that the novel isoform functions as a negative regulator of the cell cycle, and may play a distinct role. The novel isoform was named p27(Kip1R) because of its resistance to degradation.

Alternative Splicing↗
PubMed2001

Sequence and expression analyses of mu and delta transcripts in patients with Waldenström's macroglobulinemia.

Waldenström's macroglobulinemia (WM) is a malignant lymphoplasmo-proliferative disorder with monoclonal pentameric immunoglobulin (Ig)M production. The most consistent feature of clonal B cells in the bone marrow (BM) and/or lymph nodes of patients with WM is the presence of pleomorphic B-lineage cells at different stages of maturation, such as small lymphocytes, lymphoplasmacytoid cells, and plasma cells. Monoclonal lymphocytes express mu chains with or without delta chains. A recent DNA analysis of WM tumor clones showed WM to be derived from B cells that have been selected by antigen at a relatively late stage of differentiation. To further clarify the origin of WM tumor cells, we analyzed the variable (V) domain sequences of tumor derived mu and delta transcripts. The expression of delta transcripts was also examined in peripheral blood (PB) and BM using the reverse transcriptase polymerase chain reaction (RT-PCR) combined with a single-strand conformation polymorphism (SSCP) analysis. The sequences were identical among the mu and delta transcripts in each patient and the level of somatic mutation in the VH regions expressed by tumor cells was in the same range as that of IgM-only B cells and IgM(+)IgD(+) memory B cells. In our previous RT-PCR-SSCP analysis, a single dominant band of the mu isotype was observed in BM and PB in all patients. However, common dominant bands in BM and PB were detected in only one patient in a delta transcript analysis. In the rest of the patients, monoclonal delta transcripts were only detected in BM. Our results suggest that a normal counterpart of WM cells is somatically mutated IgM(+)IgD(+) and/or IgM-only B cells and the expression patterns of monoclonal mu and delta transcripts differ between BM and PB in some cases of WM.

Blood Cells↗
PubMed2001

Autoimmune neutropenia with cyclic oscillation of neutrophil count after steroid administration.

A 16-year-old female patient was evaluated for pancytopenia. She had a white blood cell count of 1.6 x 10(9)/L with 0.02 neutrophils and a platelet count of 19 x 10(9)/L. In the bone marrow, mature granulocytes were markedly decreased in number, but no atypical cells were present. Antineutrophil antibody was demonstrated by flow cytometry, and the level of platelet-associated immunoglobulin G was increased. A diagnosis of autoimmune neutropenia and thrombocytopenia was made. Interestingly, neutrophil and platelet counts fluctuated cyclically after the initiation of prednisolone therapy. The neutrophil count fluctuated between 0.1 x 10(9)/L and 7 x 10(9)/L, and the platelet count fluctuated between 19 x 10(9)/L and 175 x 10(9)/L, in 4-week cycles. Following splenectomy, neutrophil and platelet counts normalized. We believe the immune mechanism of recurrent neutropenia in this patient differs from that in other patients with cyclic neutropenia reported with stem cell disorders.

Adolescent↗
PubMed2001

CD10 and Bcl10 expression in diffuse large B-cell lymphoma: CD10 is a marker of improved prognosis.

AIMS: Diffuse large B-cell lymphoma (DLBCL), the most common subtype of non-Hodgkin's lymphoma, is clinically and pathologically heterogeneous. The Bcl10 gene was recently isolated from the breakpoint region of t(1;14)(p22;q32) in mucosa-associated lymphoid tissue (MALT) lymphomas, and is considered to be an apoptosis-associated gene. CD10 is considered to be a marker of follicular centre B-cell differentiation. To assess the clinical significance and roles of CD10 and Bcl10 in DLBCL, we analysed 138 cases, using immunohistochemical methods. METHODS AND RESULTS: CD10 expression was limited to the cytoplasm, whereas Bcl10 expression was detected in the cytoplasm and/or nuclei. CD10 expression was detected in 39 of 138 cases (28.2%), cytoplasmic Bcl10 in 68 cases (49.2%), and nuclear Bcl10 in 34 cases (24.6%). Nuclear Bcl10 was detected in 14 of 28 cases (50%) of extranodal DLBCL, but only 20 of 110 cases (18.2%) of nodal DLBCL. Cytoplasmic Bcl10 was detected in 19 of 28 cases (67.8%) of extranodal DLBCL and 49 of 110 cases (44.5%) of nodal DLBCL. CD10 expression closely correlated with improved survival (68% overall survival (OS) vs. 48% OS), but not with site of disease. A high International Prognostic Index (IPI) was considered to be a poor prognostic factor associated with a shorter OS. CD10 expression was detected in 27 of 84 cases (32.1%) with low-risk IPIs, and in 12 of 54 cases (22.2%) with high-risk IPIs. In the low-risk group, cases expressing CD10 carried a better prognosis than CD10- cases (93% OS vs. 71% OS), whereas this was not the case in the high-risk group (25% vs. 20%). CONCLUSIONS: Bcl10 expression was associated with extranodal DLBCL, but not with prognosis. CD10 expression was closely associated with improved survival, but not with risk as predicted by IPI. Overall, our results suggest that CD10 expression may be useful, in combination with clinical parameters, for determining the prognosis of DLBCL.

Adaptor Proteins, Signal Transducing↗
PubMed2001

Prevalence of hepatitis B or C virus infections in patients with non-Hodgkin's lymphoma.

BACKGROUND: Hepatitis C virus (HCV) and hepatitis B virus (HBV) are not only hepatotropic, but also lymphotropic viruses. Recently, some reports suggested that these viruses may participate in the development of malignant lymphoproliferative disorders. METHODS: We investigated the prevalence of HCV or HBV infection in 348 patients with non-Hodgkin's lymphoma (NHL). We also compared these prevalences with those in blood donors as a control group representing the general population in our area (n= 1,513,358). Next, we evaluated the clinical and pathologic characteristics of HCV- or HBV-infected NHL cases. Non-Hodgkin's lymphoma was classified according to the Working Formulation classification. RESULTS: Thirty-seven cases (14.9%) were found to be infected with HCV or HBV; of these, 20 (8.1%) were infected with HCV, and 17 (6.9%) with HBV. In male NHL patients, the rate of HCV infection was significantly higher than in an age- and sex-matched population in the same area (P < 0.001, Mantel-Haenszel test). The rate of HBV infection also tended to be higher in the population (P = 0.0551). In contrast, in female NHL patients, the rate of HCV or HBV infection was not higher than in the general population. In HCV-infected cases, 15 cases (75%) had B-cell NHL and 16 cases (80%) were classified as being in the intermediate grade; B-cell NHL comprised 83% of all NHL cases. In HBV-infected NHL cases, 11 (65%) were of B-cell type and 10 (58%) were classified as being in the intermediate grade. CONCLUSIONS: The high prevalence of HCV or HBV infections in our study population provides epidemiologic evidence suggesting that HCV and HBV infections may be involved in the development of a subgroup of NHL in males. Our investigation also revealed that both HCV- and HBV-infected NHL patients showed certain similarities in clinical and pathologic manifestations.

Adult↗
PubMed2001

Aberrant BCR-ABL transcript with intronic insertion in a patient with philadelphia chromosome-positive chronic myeloid leukemia: implications for disease progression.

The BCR-ABL fusion gene is important for the leukemogenesis of chronic myeloid leukemia (CML). A relationship between types of BCR-ABL transcripts in CML and clinical features has been proposed. We present here a patient with CML who carried an aberrant BCR-ABL transcript with an intronic sequence insert. A 26-year-old woman was diagnosed as having Philadelphia chromosome (Ph) positive CML. Reverse transcription polymerase chain reaction detected an atypically large BCR-ABL mRNA transcript. Sequencing revealed a 589bp insertion consisting of a 5' portion of BCR intron b2 and a 3' portion of ABL intron 1b between BCR exon b2 and ABL exon a2. Although the typical b2a2 transcript was undetectable initially, it appeared after intensive chemotherapy. The aberrant transcript presumably arose as a result of a lack of splicing, and chemotherapy might modify the disease course by selecting the subpopulation of the CML clone expressing typical BCR-ABL mRNA dominantly.

Adult↗
PubMed2001

[Two cases of B cell lymphoma associated with hemophagocytic syndrome].

B cell lymphoma-associated hemophagocytic syndrome (B-LAHS) is clinically characterized by hepatosplenomegaly and bone marrow invasion without lymphadenopathy and skin lesions. Several cases of B-LAHS have been reported to demonstrate histopathologic findings of intravascular lymphomatosis (IVL), which in Western countries is characterized by a high rate of skin involvement and, rarely, bone marrow involvement and hemophagocytosis. Here we describe two interesting cases of B-LAHS. One patient was a 52-year-old woman whose bone marrow showed proliferation of large CD20-positive cells and hemophagocytosis at presentation. Combination chemotherapy was not effective, and the patient died of progressive disease. At autopsy, the lymphoma cells showed extravascular proliferation in many organs such as the bone marrow and liver, whereas in the adrenal glands, the lymphoma cells showed intravascular proliferation. The other patient was a 50-year-old man who had swellings of the bilateral kidneys and adrenal glands at presentation. Skin involvement by large lymphoma cells, a rare complication of B-LAHS, was observed. At autopsy, there was no evidence of IVL. Both of these patients showed high fever and cytopenia, and the disease took an aggressive clinical course, as in other reported cases of B-LAHS.

Female↗
PubMed2001

Bcl10 expression, rearrangement and mutation in MALT lymphoma: correlation with expression of nuclear factor-kappaB.

Mucosa-associated lymphoid tissue (MALT) lymphomas usually involve extranodal sites, especially the stomach, lung and salivary glands. The Bcl10 gene was recently isolated from the breakpoint region of t(1;14) (p22;q32) in MALT lymphomas, and considered to be an apoptosis-associated gene, and involves a caspase recruitment domain (CARD)-containing protein that activates NF-kappaB. We investigated the role of Bcl10 in MALT lymphoma by analyzing its expression, rearrangement and somatic mutation, by immunostaining, reverse transcriptase-polymerase chain reaction (RT-PCR), Southern blot and PCR in 20 cases of MALT lymphoma. Expression of NF-kappaB was studied by immunostaining. Five cases of reactive lymphadenitis (RLA) were used as the control. Bcl10 rearrangement was detected in 8 of 20 (40%) MALT lymphomas, but in none of RLA. Significant Bcl10 mutation was detected only in 1 case (5%) with MALT, but not in RLA. RT-PCR showed higher density bands of Bcl10 in MALT lymphomas than in RLA. Immunostaining showed a weak Bcl10 expression in the germinal center and very weak expression in the marginal zone B-cells in RLA, which was limited to the cytoplasm. In contrast, Bcl10 was strongly expressed in MALT lymphomas, and was mainly detected in the cytoplasm, as well as in the nuclei. Bcl10 expression did not correlate with Bcl10 mutation and re-arrangements. NF-kappaB was expressed in nuclei of MALT lymphoma cells, but not in RLA. Bcl10 expression in MALT lymphoma correlated closely with NF-kappaB expression. Our results suggest that activation of Bcl10 and NF-kappaB may be important in MALT lymphomagenesis, and that nuclear localization of Bcl10 may be important in the progression of MALT.

Adaptor Proteins, Signal Transducing↗