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Biomedical subjects

A Kuramoto

Publications and source records attributed to A Kuramoto.

At least 109 records · Page 6Linked to original sources
PubMed1991

Detection of minimal residual disease in acute lymphoblastic leukemia by flow cytometry with monoclonal antibodies.

To detect more precisely the minimal residual disease in acute lymphoblastic leukemia (ALL), two-color flow cytometric analysis for the detection of cell-surface antigen (CD10; CALLA) and nuclear terminal deoxynucleotidyl transferase (TdT) was performed in the six patients with CALLA-positive ALL coexpressing TdT. In all patients, the leukemic blasts coexpressed Ia (HLA-DR), CD9, CD19, CD20, CD24, and CD10. Five of six patients achieved complete remission, but one has so far relapsed. No leukemic blasts (CD10+, TdT+) were detected at the time of complete remission. During maintenance chemotherapy, leukemic blasts coexpressed C10 and TdT were found 2.32% in the patient's peripheral blood by two-color analysis, whereas no obvious leukemic cells were recognized morphologically. The patient relapsed leukemia with the same phenotype 4 weeks after the examination. On the basis of our findings, we suggest that two-color flow cytometric analysis with the use of these antibodies is quite valuable to detect the minimal residual leukemic cells in a patient with ALL. The reduction of leukemic cells below the threshold of detection of methods currently available appears to be necessary to achieve a cure in ALL. Hence accurate diagnosis of ALLs with monoclonal antibodies (MAbs) should contribute substantially to the development of an effective form of therapy for their cure.

Antibodies, Monoclonal↗
PubMed1991

Autocrine and/or paracrine mechanism operate during the growth of human bone marrow fibroblasts.

The growth of human marrow fibroblasts was studied at various plating cell densities. The growth rate of fibroblasts cultured with human plasma derived serum (PDS) increased depending on the cell density plated, whereas fibroblasts cultured with human serum proliferated almost independent of the cell density. Conditioned medium obtained from the culture with PDS at high cell density enhanced the growth of fibroblasts plated at low density, as well as that of fibroblast colony forming cells. Characterization of this conditioned medium showed heat unstable and acid stable peptide factor(s) with high molecular weight (approximately 10(6)) may be responsible for this activity. These results suggest that autocrine and/or paracrine mechanism can operate during the proliferation of marrow fibroblasts, a process thought to be involved in the progression of marrow fibrosis.

Adult↗
PubMed1991

Homotypic cell aggregations of human myeloma cells with ICAM-1 and LFA-1 molecules.

Some myeloma cells freshly isolated from bone marrow aspirates in human myelomas and some myeloma cell lines formed spontaneous cell aggregations in vitro (homotypic cell aggregations). In order to clarify the surface molecules involved in homotypic cell aggregations and physiological roles of these cell aggregations, we investigated the expressions of intercellular adhesion molecule 1 (ICAM-1) and lymphocyte function-associated antigen 1 (LFA-1) on 20 samples of freshly isolated myeloma cells and three myeloma cell lines and the effect of anti-ICAM-1 and anti-LFA-1 alpha antibodies on myeloma cell proliferation in vitro. All myeloma cells that we tested expressed ICAM-1 on their surface. Among them, myeloma cells that strongly coexpressed LFA-1 alpha, formed homotypic cell aggregates in vitro. These spontaneous cell aggregations were completely released by adding either anti-ICAM-1 or anti-LFA-1 alpha antibody. During short-term culture, spontaneous proliferation of myeloma cells in vitro and their proliferative responses to recombinant interleukin-6 (rIL-6) were not affected by pretreatment of myeloma cells with anti-ICAM-1 or anti-LFA-1 alpha antibody. Therefore these data suggest that homotypic cell aggregation of myeloma cells is mediated by ICAM-1 and LFA-1 molecules, but myeloma cell proliferation may not be modulated by these adhesion molecules during short-term cultures.

Antigens, CD↗
PubMed1991

Increased expression of the c-myc gene may be related to the aggressive transformation of human myeloma cells.

Alteration and abnormal expression of the c-myc oncogene were investigated in human multiple myeloma. Human myeloma cells were highly purified (more than 95%) from bone marrow aspirates in 14 cases of advanced multiple myelomas and one case of plasma cell leukaemia. Southern blotting revealed that a rearranged configuration of c-myc gene was found in only one case of them, but this was a novel truncation of the gene in its coding exon II; a rearranged 3.4 kb band was detected by digestion with Xba I using c-myc exon II probe, but no rearranged band was found using exon III probe. In this case, the truncated c-myc allele was not transcribed; normal sized (2.4 kb) c-myc mRNA was markedly expressed, but no aberrant mRNA was detected. On the other hand, by Northern blotting, the nine cases, including the case with the rearranged c-myc gene, showed increased expression of normal sized (2.4 kb) c-myc mRNA. Elevated c-myc mRNA expressions were well related to the in vitro proliferation (3H-TdR uptake), but not to IL-6 response. Interestingly, extremely high expressions of c-myc mRNA were detected in two cases of aggressive myelomas, including the case with the rearranged c-myc gene, and in one of plasma cell leukaemia. These two cases of aggressive myelomas were the ones who showed the markedly high 3H-TdR uptakes, and had the common clinical features with the formation of an extramedullary mass and very short survival. These results suggest that the activation of c-myc gene could induce high proliferative activities and the subsequent aggressive transformation of myeloma cells.

Blotting, Northern↗
PubMed1991

[Parallel loss of c-FMS and GM-CSF genes in myeloid leukemias with 5q-chromosome].

DNA contents of c-FMS and GM-CSF genes were analyzed by densitometer in nine patients with myelodysplastic syndrome or acute myeloid leukemia associated with abnormality of chromosome 5. Five patients with deletion in the long arm of chromosome 5 had loss of both c-FMS and GM-CSF genes. These findings suggest that c-FMS oncogene and GM-CSF gene locating in the critical region on chromosome 5 seem to have an important role in the process of leukemogenesis.

Aged↗
PubMed1990

Blastic transformation in essential thrombocythemia. In vitro differentiation of blast cells into granulocytic, erythroid, and megakaryocytic lineages.

A 57-year-old man with essential thrombocythemia (ET) developed myelofibrosis, that progressed to a blastic transformation state. The characteristics of the blastic cells were serially studied both morphologically and phenotypically as well as in cell culture. The blastic cells that were first detected in peripheral blood had features of myeloid stem cells with slight differentiation toward megakaryocytic lineage. However, later in the course, most of the blastic cells were immature. During culture in the presence of human plasma-derived serum (PDS), some blastic cells obtained at the initial stage differentiated, mainly to both granulocytes and macrophages morphologically, but later tended to differentiate into both megakaryocytes and macrophages. Finally the blasts appeared to have lost their ability to differentiate morphologically. However, the blasts formed mixed colonies consisting of erythroblasts, granulocytes, macrophages, and immature blasts when cultured in methylcellulose with PHA-leukocyte conditioned medium. In addition, the blastic cells in suspension culture strongly expressed phenotypic features which are characteristic of erythroblasts, in the presence of both PDS and 12-0-tetradecanoylphorbol 13-acetate (TPA), whereas they expressed features of megakaryoblasts in the presence of PDS alone. These results suggest that essential thrombocythemia is of myeloid stem cell origin. This is the first case in the literature in which a clonal evolution in ET has been followed closely, essential events were identified serially, and the blastic cells, which appeared as a result of the progression of ET, were found to have the capability to differentiate toward the three myeloid lineages.

Blast Crisis↗
PubMed1990

Analysis of platelet cytoskeleton assembly during platelet activation in Hermansky-Pudlak syndrome and thrombasthenia.

Time course change of the platelet cytoskeletal protein component in the Triton X-100 insoluble fraction after stimulation was analyzed in Hermansky-Pudlak syndrome and thrombasthenia. In Hermansky-Pudlak syndrome (HPS), a 31 kDa protein, myosin, actin, and a 100 kDa protein assembled as in the normal platelets at the shape change and release reaction phases after ADP or collagen stimulation, suggesting that, the deficient dense granule content do not lead to an abnormal platelet cytoskeletal protein assembly. In thrombasthenia (Type I), myosin increased at the shape change and release reaction phases as it does in normal platelets, but actin and the 100 kDa protein increased only at the initial activation phase, and then subsequently decreased to the level of the resting phase. The actin-binding protein (ABP) and the 31 kDa protein increased a little following stimulation. Similar cytoskeletal protein change after stimulation were found in normal platelets which were prevented from the aggregation process by chelating the external Ca2+ or by using synthetic decapeptide of fibrinogen gamma-chain of carboxyl terminus. The decreased platelet cytoskeletal protein assembly in thrombasthenia or in platelets stimulated without aggregation, was derived from a loss of the platelet aggregation process due to the defect of GP IIb-IIIa complex or an interaction failure between GP IIb-IIIa complex and fibrinogen. The interaction between platelets and either fibrinogen or fibrin can induce a more stable platelet cytoskeletal protein assembly, however, agonistic stimulation without these interactions cannot do it directly.

Actins↗
PubMed1990

Effect of glucocorticoids on the biologic activities of myeloma cells: inhibition of interleukin-1 beta osteoclast activating factor-induced bone resorption.

Regulatory effects of glucocorticoids (dexamethasone) on myeloma cells as well as bone resorption in multiple myeloma were investigated. Glucocorticoids significantly inhibited proliferation of myeloma cells, and decreased the messenger RNA (mRNA) expressions of interleukin-6 (IL-6) and secretory type immunoglobulin G (IgG). The inhibitory effects of glucocorticoids on myeloma cell proliferation could be due to the decreased expression of IL-6 mRNA, decreased IL-6 production, and thus suppression of autocrine growth by IL-6, which is an autocrine growth factor for myeloma cells as reported previously (Nature 332:83, 1988). Glucocorticoids also inhibited M-protein secretion by decreasing the levels of secretory type Ig mRNA. On the other hand, because IL-1 beta rather than lymphotoxin is considered to be a major osteoclast activating factor (OAF) produced by myeloma cells, and glucocorticoids decreased the expression of IL-1 beta mRNA and markedly suppressed the bone resorbing activity induced by IL-1 beta OAF in 45Ca-release bone resorption assay, it is suggestive that glucocorticoids could inhibit bone resorption induced by IL-1 beta OAF in multiple myeloma. Therefore, from these data it is concluded that glucocorticoids could be more effective chemotherapeutic agents in multiple myeloma than we expected, especially with regards to the inhibitory effects on proliferation and M-protein secretion from myeloma cells, as well as bone resorption by myeloma cells.

Blotting, Northern↗
PubMed1990

Varied expressions of receptors on the human megakaryoblastic cell line MEG-01 by monoclonal antibodies.

We herein describe the regulation of specific receptors on the megakaryoblastic cell line MEG-01 by means of fluorescence-activated cell sorting (FACS IV) with a panel of monoclonal antibodies (MAbs). MEG-01 cells expressed GpIIb/IIIa (CD41a) and OKM5 (CD36) antigens on their cell surface, whereas they showed only a little expression of GPIb (CD42b), suggesting that these are megakaryoblastic cells. The up regulation of von Willebrand factor receptor (GPIb) and thrombospondin receptor (GPIV) and the down regulation of fibrinogen receptor (GPIIb/IIIa) and C3bi receptor (CD11b) were found by incubation with MAbs AN51 (CD42b), OKM5 (CD36), J15 (CD41a), and OKM1 (CD11b), respectively. This phenomenon was enhanced in the Ca2+ containing medium, except for the experiment with OKM5 (CD36) MAb. We thus suggest that several kinds of receptors on the surface of MEG-01 cells are dexterously regulated through stimulation from outside the cell.

Antibodies, Monoclonal↗
PubMed1990

Discordance between phenotype and function of Japanese adult T cell leukemia cells.

Phenotypes of cells from 12 patients with ATL were analysed by means of a fluorescence-activated cell sorter by utilizing a panel of monoclonal antibodies. A majority of the cells from peripheral blood coexpressed the antigens against MAbs CD2, CD3, CD4, CD5, Ti (WT31), CD25, CD38, CD45, and CD29, but did not express the antigens against CD1, CD13, CD14, CD33, CD36, CD10, CD19, CD20, CD21, CD24, CD41, CD42, CD45RA, CD56, and CD57. The expression of antigen for TQ-1 or Leu8 was variable. Surface immunoglobulins were not detected. Phenotypes of cultured cells established by utilizing recombinant interleukin II were similar to those of the uncultured peripheral blood lymphoid cells except for the lack of expression of CD8. By means of two-color fluorescence, the ATL cells possessing CD4 in peripheral blood and culture coexpressed CD29, but did not express CD45RA. The suppression of PWM-induced B-cell immunoglobulin synthesis by normal T and B cells was found in five cases in the presence of ATL cells. The ATL cells demonstrated helper T-cell phenotypes (CD4+, CD29+) with suppressor function, paradoxically. We conclude that the phenotype of the ATL cells was CD4+, CD29+, and CD45RA- but that the function of these cells was of suppressor T-cells. Our results inevitably suggest the possible existence of suppressor T-cells with CD4+, CD29+ phenotype in persons without evidence of any underlying hematologic disorder.

Antibodies, Monoclonal↗
PubMed1990

Distribution of cell surface glycoprotein CD9 (P24) antigen on megakaryocyte lineage leukemias and cell lines.

We herein describe CD9 (p24) antigen as existing on the cell surface of megakaryocyte lineage leukemias as well as megakaryocytic leukemia cell line, MEG-01 and HEL, by means of fluorescence-activated cell sorter (FACS IV) with a panel of monoclonal antibodies (Mabs). We found CD9 antigen expression on the cell surface of megakaryoblastic leukemias as well as MEG-01 and HEL cells. Furthermore, CD9 antigen expression increased while culturing these cells with phorbol esters, and was also found in the cytoplasm by means of indirect immunofluorescence test. These findings clearly showed that CD9 antigen exists on the cell surface of megakaryocytic cells which are capable of synthesizing the CD9.

Antigens, CD↗
PubMed1990

Platelet derived growth factor messenger RNA is increased in bone marrow megakaryocytes in patients with myeloproliferative disorders.

Platelet derived growth factor (PDGF) has been suggested to play an important role in the pathogenesis of myelofibrosis, which often occurs in patients with myeloproliferative disorders (MPD). We examined the expression level of PDGF mRNA in bone marrow megakaryocytes from 13 MPD patients by in situ hybridization, using cDNA probes for both human PDGF A chain and B chain (c-sis). The mRNA level for both chains in the patients was significantly higher than that in control patients, and was markedly higher for one patient with essential thrombocythemia and one with polycythemia vera. Transcripts for A chain and B chain were expressed with a positive correlation in the MPD patients. Using the marrow fibroblast proliferation assay, we found PDGF activity in purified megakaryocytes from one of the MPD patients with high mRNA level to be similar to that from one control patient. In addition, PDGF was previously shown to be decreased in circulating platelets from MPD patients. These results may suggest that, in some patients, PDGF is synthesized in megakaryocytes at a high rate, but some fraction is released into the bone marrow environment, if the level of PDGF mRNA is assumed to be linearly related to the protein synthesized. This might be one possible mechanism causing marrow fibrosis in MPD patients.

Adult↗
PubMed1990

FAB L3 type of B-cell acute lymphoblastic leukemia (B-ALL) without chromosome abnormalities.

Acute lymphocytic leukemias (ALLs) are morphologically classified into L1, L2, and L3. The former two types are phenotypically constituted of quite heterogeneous ALLs. In the present study, phenotypes of cells from five L3 type ALL were analysed in FACS-IV using a panel of monoclonal antibodies (MAbs). The leukemic cells of all these patients coexpressed la (HLA-DR), CD19, CD20, CD21, CD24, CD38, and surface immunoglobulins, whereas a negative reaction with MAbs CD1, CD2, CD3, CD4, CD7, CD8, and Ti (WT31), Ti gamma A, delta TCS 1, and anti TCR-gamma/delta was observed. Neither myeloid-monocyte-erythroid nor megakaryocyte related cell surface antigens were detected in these cases with L3 type ALL. Chromosomal analysis of the ALL cells from two cases revealed a normoploid karyotype with specific translocation t(8;14)(q24;q32), whereas it was normal (46XY or 46XX) for the remaining three cases. Expression of myc oncogene was high in the former group, but low in the later one. Basing from our findings, we conclude that L3 type ALL is heterogeneous with respect to immunophenotypes, cytogenetics and oncogene analysis.

Antibodies, Monoclonal↗
PubMed1990

Isolation and characterization of VP-16 resistant human leukemia cell line.

VP-16 resistant cells, designated VP-16K6-1 (K6-1) were isolated from human acute lymphoblastic leukemia cell line RPMI 8402. IC50 value against VP-16 were 11-fold higher than their sensitive parental cell line. The membrane permeability of the drug was not responsible for resistance in K6-1 cells. K6-1 cells showed resistance in drug-induced DNA strand breaks (single strand breaks) determined by the alkaline sucrose gradient sedimentation method. Dot-blot analysis of RNA extracted from 2 cell lines showed that the mRNA levels of DNA topoisomerase II in K6-1 cells decreased slightly compared with that of parent cells. However, Topo II activities were similar in wild-type and K6-1 cells. In addition, K6-1 cells exhibited cross-resistance only to VM-26. These data suggest that a reduced intracellular Topo II level may contribute to drug resistance as an important factor in K6-1 cells.

DNA Replication↗