Biomedical subjects

S Fukuhara

Publications and source records attributed to S Fukuhara.

At least 91 records · Page 5Linked to original sources

PubMed1999

Apoptosis induced by the myelodysplastic syndrome-associated NPM-MLF1 chimeric protein.

The NPM-MLF1 chimeric protein is produced by the t(3;5)(q25.1;q34) chromosomal translocation, which is associated with myelodysplastic syndrome (MDS) prior to progression into acute myeloid leukemia (AML). Here we report that K562 human leukemia cells ectopically expressing NPM-MLF1, but not those with wild-type MLF1, were gradually eliminated from the culture by undergoing apoptosis. NIH3T3 mouse fibroblasts engineered to overexpress NPM-MLF1 grew normally but serum deprivation triggered apoptotic cell death with slower kinetics than did other well-known apoptotic inducers such as c-Myc or E2F-1. Quantitative analysis of apoptotic induction confirmed that, neither NPM nor MLF1, but the NPM-MLF1 fusion protein was able to induce apoptosis. Analyses using a variety of deletion mutants of NPM-MLF1 revealed that induction of apoptosis required the N-terminal domain of MLF1 and the NPM domain containing nuclear localization signal and that removal of the NPM dimerization domain markedly impaired the ability to induce apoptosis. Co-expression of Bcl-2 rescued NIH3T3 fibroblasts from NPM-MLF1-mediated cell death without affecting the expression level or the subcellular localization of NPM-MLF1 and enabled cells to progress into S phase in low serum. These findings provide an NPM-MLF1-mediated novel mechanism of apoptotic induction and imply that NPM-MLFI in collaboration with anti-apoptotic oncoproteins may play an important role in multi-step progression from MDS to AML.

3T3 Cells↗

PubMed1999

A novel PDZ domain containing guanine nucleotide exchange factor links heterotrimeric G proteins to Rho.

Small GTP-binding proteins of the Rho family play a critical role in signal transduction. However, there is still very limited information on how they are activated by cell surface receptors. Here, we used a consensus sequence for Dbl domains of Rho guanine nucleotide exchange factors (GEFs) to search DNA data bases, and identified a novel human GEF for Rho-related GTPases harboring structural features indicative of its possible regulatory mechanism(s). This protein contained a tandem DH/PH domain closely related to those of Rho-specific GEFs, a PDZ domain, a proline-rich domain, and an area of homology to Lsc, p115-RhoGEF, and a Drosophila RhoGEF that was termed Lsc-homology (LH) domain. This novel molecule, designated PDZ-RhoGEF, activated biological and biochemical pathways specific for Rho, and activation of these pathways required an intact DH and PH domain. However, the PDZ domain was dispensable for these functions, and mutants lacking the LH domain were more active, suggesting a negative regulatory role for the LH domain. A search for additional molecules exhibiting an LH domain revealed a limited homology with the catalytic region of a newly identified GTPase-activating protein for heterotrimeric G proteins, RGS14. This prompted us to investigate whether PDZ-RhoGEF could interact with representative members of each G protein family. We found that PDZ-RhoGEF was able to form, in vivo, stable complexes with two members of the Galpha12 family, Galpha12 and Galpha13, and that this interaction was mediated by the LH domain. Furthermore, we obtained evidence to suggest that PDZ-RhoGEF mediates the activation of Rho by Galpha12 and Galpha13. Together, these findings suggest the existence of a novel mechanism whereby the large family of cell surface receptors that transmit signals through heterotrimeric G proteins activate Rho-dependent pathways: by stimulating the activity of members of the Galpha12 family which, in turn, activate an exchange factor acting on Rho.

Amino Acid Sequence↗

PubMed1999

HGF activates signal transduction from EPO receptor on human cord blood CD34+/CD45+ cells.

Hepatocyte growth factor (HGF) is a multifunctional cytokine with early hematopoiesis-stimulatory activity. Here, we focus on its erythropoiesis-stimulatory effect on highly purified human hematopoietic progenitor cells (CD34+/CD45+ cells) derived from the cord blood. In immunoblot analyses, c-met protein (a receptor of HGF) was detected in the CD34+/CD45+ cells, although the expression levels were different among samples. The c-met expression was facilitated by incubation of the cells with stem cell factor (SCF) or interleukin 3 (IL-3), even if the expression level had been low. IL-6, G-CSF, or erythropoietin (EPO) did not show such a stimulatory effect on the c-met expression of the cells. When HGF was added to the CD34+/CD45+ cells in the presence of SCF, the numbers of CD36+/CD11b- cells (very early erythroid lineage cells) and BFU-E increased. EPO-dependent tyrosine phosphorylation of Stat 5 also increased, but the EPO receptor (EPO-R) expression remained unchanged in the CD34+/CD45+ cells treated with SCF + HGF. Our present study suggests that stimulation of the HGF/c-met signal is concomitant with induction of c-met protein by SCF. The subsequent enhancement of signal transduction via the activation of Stat 5 from the EPO-R plays a crucial role in the commitment of hematopoietic stem cells into erythroid lineage cells.

Antigens, CD34↗

PubMed1999

A crucial role of caspase 3 and caspase 8 in paclitaxel-induced apoptosis.

The anticancer drug paclitaxel is well known as an inhibitor of microtubule depolymerization, resulting in mitosis arrest. We investigated the mechanism underlying antitumor effects of paclitaxel on the lung adenocarcinoma cell line LC-2-AD. Less than 10 microg/ml paclitaxel induced mitosis arrest upon LC-2-AD, followed by apoptosis, but more than 30 microg/ml paclitaxel induced apoptosis without mitosis arrest. LC-2-AD with less than 1 microg/ml paclitaxel showed a loss of mitochondrial transmembrane potential (deltapsim), which correlated with antitumor effects. However, LC-2-AD with more than 10 microg/ml paclitaxel showed slight changes in the loss of deltapsim in spite of its ability to induce apoptosis significantly. The cleavage of caspase 3, caspase 8, and DFF45/ICAD was also observed in paclitaxel-induced apoptosis, and the inhibitor of caspase 3 and caspase 8 inhibited both antitumor effects and apoptosis induced by paclitaxel. These results suggest that activation of caspase 3 and caspase 8 plays a crucial role in paclitaxel-induced apoptosis under any concentrations of paclitaxel.

Antineoplastic Agents, Phytogenic↗

PubMed1999

Novel Molecular Mediators in the Pathway Connecting G-protein-coupled Receptors to MAP Kinase Cascades.

The family of receptors coupled to heterotrimeric GTP-binding proteins (G proteins) constitutes the largest group of integral membrane proteins involved in signal transduction. These receptors participate in many important biological functions, ranging from photoreception to neurotransmission and exocytosis, as well as in processes such as embryogenesis, angiogenesis, tissue regeneration and normal and aberrant cell growth. Initial studies addressing the functioning of these receptors had focused primarily on second messenger-generating systems. Here, the authors survey the current knowledge on how this family of receptors transduces signals to the nucleus through an intricate network of nucleotide exchange factors, small GTPases, and cytoplasmic kinases which, in turn, control gene expression by phosphorylating nuclear regulatory molecules.

Journal Article↗

PubMed1999

Long-term follow-up results of adult patients with acute lymphocytic leukemia or lymphoblastic lymphoma treated with short-term, alternating non-cross-resistant chemotherapy: Japan Clinical Oncology Group Study 8702. Lymphoma Study Group.

BACKGROUND: Patients with acute lymphocytic leukemia (ALL) and those with lymphoblastic lymphoma (LBL) have overlapping clinical and immunophenotypic features and they have been treated with the same or very similar chemotherapy regimens. The goal of this multi-institutional phase II trial was to evaluate the therapeutic efficacy of a short-term, six-drug chemotherapy regimen for adult patients with untreated ALL or LBL. METHODS: Forty-six eligible patients, 41 with ALL and five with LBL, were treated with a short-term (planned total therapy duration; 36-38 weeks), simplified chemotherapy program; two courses of VEPA-L (vincristine, cyclophosphamide, prednisolone, doxorubicin, I-asparaginase plus intrathecal methotrexate and prednisolone) followed by four courses of M-VEPA (methotrexate plus VEPA), without the traditional maintenance therapy using daily 6-mercaptopurine and weekly methotrexate. RESULTS: Thirty-six (78%; 95% confidence interval 64-89%) of the 46 eligible patients achieved complete remission (CR). Among the 36 patients who achieved CR, four (11%) died of treatment complications, 26 (72%) relapsed and six (17%) remain alive in continuous CR. The median survival for all 46 eligible patients is 14 months and the median disease-free survival (DFS) for the 36 patients who achieved CR is 11 months. The estimate of the proportion of survival at 7 years of all 46 eligible patients is 15% at a median follow-up time of 96 months and that of DFS of the 36 patients achieving CR is 17% at a median follow-up time of 93 months. Subgroup analysis showed that an elevated serum C-reactive protein (CRP) level, age of 30 years or older, the presence of B-symptom and T-cell phenotype were likely to be associated with shortened survival. Although the observed CR rate (78%) is within the range of satisfaction, the long-term survival rate (15%) is inferior to those of published programs incorporating maintenance therapy. CONCLUSIONS: A fraction of adult patients with ALL or LBL are curable with a short-term, six-drug chemotherapy regimen. However, this simplified therapy of shorter duration cannot be recommended.

Adolescent↗

PubMed1999

Use of prescribed drugs among older people in Japan: association with not having a regular physician.

OBJECTIVES: Minimizing the overuse of prescribed drugs among older people is a goal of geriatricians and healthcare policy makers. Indirect evidence indicates that use of prescribed drugs is more common in Japan than in some Western countries, but the actual situation in Japan is unknown. The first aim of this study was to clarify the use of prescribed drugs among older people in Japan. We also tested the hypothesis that using five or more prescribed drugs is associated with a situation that is modifiable and is relatively common in Japan: not having a regular physician. DESIGN: A cross-sectional survey. PARTICIPANTS: Subjects representing the Japanese general population aged 65 years and older were selected by two-stage stratified sampling; 617 persons were eligible for the study. MEASUREMENTS: Each subject was given a self-report questionnaire about current medications, sociodemographic characteristics, current state of health, health-related quality of life, and whether they had a regular physician. Among users of prescribed drugs, the association between using five or more prescribed drugs and not having a regular physician was assessed by univariate analysis and by stepwise logistic regression. RESULTS: The questionnaire was returned by 491 (80%) of the eligible subjects, 299 (61%) of whom were taking at least one prescribed drug. Nearly 30% of those subjects were taking at least five prescribed drugs. The distribution of the number of prescribed drugs being taken was positively skewed; the minimum was one and the maximum was 17, the middle 50% of the values ranged from two to five, and the median was three. About half of those who were taking at least five prescribed drugs did not have a regular physician. Compared with those who had a regular physician, those who did not were 2.5 times more likely to be taking at least five prescribed drugs (95% confidence interval, 1.4 - 4.6). CONCLUSIONS: Older people in Japan are less likely to be taking many prescribed drugs if they have the continuity of care provided by a regular physician.

Aged↗

PubMed1999

Survey of Japanese physicians' attitudes towards the care of adult patients in persistent vegetative state.

OBJECTIVES: Ethical issues have recently been raised regarding the appropriate care of patients in persistent vegetative state (PVS) in Japan. The purpose of our study is to study the attitudes and beliefs of Japanese physicians who have experience caring for patients in PVS. DESIGN AND SETTING: A postal questionnaire was sent to all 317 representative members of the Japan Society of Apoplexy working at university hospitals or designated teaching hospitals by the Ministry of Health and Welfare. The questionnaire asked subjects what they would recommend for three hypothetical vignettes that varied with respect to a PVS patient's previous wishes and the wishes of the family. RESULTS: The response rate was 65%. In the case of a PVS patient who had no previous expressed wishes and no family, 3% of the respondents would withdraw artificial nutrition and hydration (ANH) when the patient did not require any other life-sustaining treatments, 4% would discontinue ANH, and 30% would withhold antibiotics when the patient developed pneumonia. Significantly more respondents (17%) would withdraw ANH in the case of a PVS patient whose previous wishes and family agreed that all life support be discontinued. Most respondents thought that a patient's written advance directives would influence their decisions. Forty per cent of the respondents would want to have ANH stopped and 31% would not want antibiotics administered if they were in PVS. CONCLUSIONS: Japanese physicians tend not to withdraw ANH from PVS patients. Patients' written advance directives, however, would affect their decisions.

Adult↗

PubMed1999

Effect of ticlopidine on platelet-derived microparticles in patients with connective tissue diseases.

We evaluated the plasma concentrations of platelet activation markers and platelet-derived microparticles (PMP) in patients with connective tissue diseases complaining of peripheral circulation disorders (n = 16) and studied the effect of ticlopidine hydrochloride (ticlopidine) on PMP generation. There were significant differences in the levels of PMP and a platelet activation marker between before and after treatment with ticlopidine (PMP: 695 +/- 393 vs. 354 +/- 206/10(4) platelets, p < 0. 01; platelet CD63: 9.13 +/- 5.64 vs. 5.22 +/- 2.74%, p < 0.05). On the other hand, markers of vascular endothelium, such as vascular endothelium-derived small vesicles and serum thrombomodulin levels, were not affected by the administration of ticlopidine. Levels of cytokines and soluble adhesion molecules remained unchanged by ticlopidine administration. These findings suggest that ticlopidine may be useful for the inhibition of PMP-dependent vascular damage in patients with connective tissue diseases complaining of peripheral circulation disorders.

Antigens, CD↗

PubMed1999

Significance of platelet-derived microparticles and activated platelets in diabetic nephropathy.

We measured levels of platelet-derived microparticles (PMP), which have coagulative activity and are produced by platelet activation or physical stimulation, and CD62P/CD63-positive platelets in patients with diabetes mellitus to determine their clinical significance and effects on complications of diabetes including diabetic nephropathy. We also compared these levels before and after administration of the antiplatelet drug cilostazol. Plasma PMP and CD62P/CD63-positive platelet levels were significantly higher in patients with diabetes mellitus than normal controls. CD62P-positive platelet levels were significantly higher in patients with nephropathy than in patients without complications. After administration of cilostazol, PMP and CD62P/CD63-positive platelet levels were significantly decreased. The increases in platelet activity and its related procoagulant activity appear to account in part for the hypercoagulability observed in diabetes mellitus. Our findings suggest that activated platelets might play a role in the development of diabetic nephropathy. Furthermore, antiplatelet therapy with cilostazol for diabetic patients may be useful as antithrombin therapy including antiplatelet therapy, since it suppresses the production of intrinsic coagulants produced by platelet activation.

Antigens, CD↗

PubMed1999

Telemedicine in neurosurgery using international digital telephone services between Japan and Malaysia--technical note.

A new image transmission and teleconference system using international digital telephone services was established between Japan and Malaysia. This new system consists of an ordinary personal computer, image scanner, and terminal adapter for digital telephone lines. The quality of images transferred using this system was high enough for diagnosis and discussion except for images such as radiographs requiring huge data transfer. Transmission of one image took approximately 20 seconds. The cost performance was almost equal to the conventional mailing system. The most remarkable advantage of this new system is the high quality of transferred images, the cost and time performance, and security of the medical information. New communication systems using international digital networks including the internet may allow re-distribution of medical resources between advanced countries and developing countries in neurosurgery.

Academic Medical Centers↗

PubMed1999

Genetic analysis of HLA- and HPA-typing in idiopathic (autoimmune) thrombocytopenic purpura patients treated with cepharanthin.

We performed genetic analysis of human leukocyte antigen (HLA) and human platelet antigen (HPA) in 45 patients with cepharanthin-treated idiopathic thrombocytopenic purpura. HLA-typing was performed by the polymerase chain reaction-restriction fragment length polymorphism method, and HPA-typing by a polymerase chain reaction-sequence-specific primer method. There were 14 responders and 31 nonresponders. Responders included many patients who had already been treated with prednisolone. HLA-DRB1*0901 was significantly more common in responders than in nonresponders. In contrast, HLA-DRB1*0410 and DQB1*0401 were significantly more common in nonresponders. The a/b genotype of HPA-2a/2a (Ko(b)/Ko(b)) was significantly increased in responders. In contrast, HPA-2a/2b (Ko(b)/Ko(a)) and HPA-3a/3b (Bak(a)/Bak(b)) were significantly more common in nonresponders. These findings suggest that genetic studies of HLA and HPA can predict the response of idiopathic thrombocytopenic purpura to cepharanthin.

Adult↗

PubMed1999

Effects of nilvadipine on cytokine-levels and soluble factors in collagen disease complicated with essential hypertension.

We examined some immunological parameters, particularly cytokines and soluble factors in collagen diseases complicated with essential hypertension. We also investigated the effects of Nilvadipine on immunological parameters after treatment with this drug for six months. The frequency of helper/inducer T cells (CD4+ CD8- cells, CD4+ CD45RA- cells) decreased in the peripheral blood on a 6 month treatment with nilvadipine. There was a significant decrease of suppressor/inducer T cells (CD4+ 45RA+ cells), and an insignificant decrease of activated T cells (CD3+ HLA-DR+ cells) and memory T cells (CD45RA- CD45RO+ cells) after treatment. Before treatment with Nilvadipine, interleukin-1beta, tumor necrosis factor-a, and interleukin-6 levels increased higher in the patients than in healthy volunteers. However, interleukin-1beta and interleukin-6 concentrations tended to decrease after treatment with Nilvadipine. Besides, tumor necrosis factor-alpha decreased significantly after treatment. The soluble interleukin-2 receptor concentrations also showed a decreased tendency after treatment, although high concentrations were found in the patients before treatment. In contrast, soluble human leukocyte antigen-1 and soluble thrombomodulin levels showed no significant change after treatment. These results suggest that Nilvadipine inhibits the generation of cytokines derived from activated T lymphocytes. Nilvadipine, calcium antagonist, may be useful for inhibition of vascular complication in collagen diseases.

Adult↗

PubMed1999

t(9;14)(p13;q32) involving the PAX-5 gene: a unique subtype of 14q32 translocation in B cell non-Hodgkin's lymphoma.

Newly identified t(9;14)(p13;q32) is a subtype of the well-defined 14q32 translocation and is closely associated with lymphoplasmacytic lymphoma (Revised European-American Classification of Lymphoid Neoplasms). The analysis of the breakpoint of t(9;14) unraveled its molecular structure as being the recombination of the PAX-5 gene on 9p13 with IgH locus located on 14q32. The molecular event does not seem to cause structural alteration of the protein product of PAX-5 and, instead, its deregulation is most likely the essential outcome of this translocation. In vitro experiments have shown that the overexpression of PAX-5 resulted in enhanced proliferation of B cells, implicating its potential capacity for lymphomagenesis. PAX-5 is crucial during most developmental stages of B cells mainly through regulating the expression of a variety of genes. Therefore, elucidating the nature of the altered expression of these downstream genes as well as the PAX-5 gene itself would be indispensable in clarifying the precise mechanism of lymphomagenesis caused by t(9;14).

Animals↗

PubMed1999

[A model of quality of life in the patients with Crohn's disease].

PURPOSE: To identify the integrated impact of psychological, social, and clinical factors onto the quality of life (QOL) in the patients with Crohn's disease. SUBJECTS AND METHODS: Two hundred twenty two out-patients participated in a cross-sectional questionnaire survey in which health-related QOL (SF36), disease-specific symptoms, psychological adaptation and social support were measured. Multi-variable regression models were used to test the impact of clinical, psychological, and social factors on the patient's QOL and symptom reports. RESULTS: The patient's symptoms and health-related QOL were significantly associated not only with disease activities, but also with the patient's psychological adaptation and the quality of social support. CONCLUSION: The results strongly suggest that a psychoeducational intervention may be useful in combination with a clinical intervention to improve the patient's QOL.

Adult↗

PubMed1998

Expression of functional tissue factor on small vesicles of lipopolysaccharide-stimulated human vascular endothelial cells.

We examined tissue factor expression on lipopolysaccharide-stimulated endothelial cells and their small vesicles by using specific antibodies and flow cytometry. Tissue factor functional activity was also assessed by activation of factor X. Endothelial cells were stimulated with 10 microg/ml of lipopolysaccharide in M-199/bovine serum albumin. Flow cytometry showed that expression of tissue factor on endothelial cells reached a maximum at 6 hours after stimulation, whereas that on small vesicles reached a maximum after 12 hours. Factor X activation mediated by factor VIIa and tissue factor was observed over a similar time course and was inhibited by the addition of antitissue factor antibody. Immunoelectron microscopy suggested that small vesicles with expression of some tissue factor were produced from the surface of endothelial cells. Our findings thus showed that tissue factor on endothelial cells produced by lipopolysaccharide stimulation was partly released to small vesicles. This may cause disseminated intravascular coagulation and related coagulation disorders.

Cells, Cultured↗

PubMed1998

Molecular features of a new human lymphoma cell line carrying both BCL2 and BCL6 gene rearrangements.

Chromosomal translocations and/or their molecular equivalents involving the BCL6 gene on 3q27 band have been suggested to be involved in the development of non-Hodgkin's lymphoma of B-cell type (B-NHL). The rearrangement of BCL6 sometimes coexists with other translocations specific to B-NHL. Here, we report a novel B-cell lymphoma cell line, YM, established from a patient with diffuse large cell lymphoma. The YM cells expressed B-cell-associated antigens in addition to mu delta/kappa monoclonal immunoglobulin. Southern blot analysis of DNA from YM cells demonstrated rearrangement of the BCL2 gene within the 5' flanking region (5'-BCL2). Polymerase chain reaction (PCR) using primer pairs for the BCL2 exons 1 and 2, and for the constant region of the immunoglobulin kappa light chain gene (IGkappa) revealed PCR products encompassing the 5'-BCL2/IGkappa fusion, indicating that the YM cells had a t(2;18)(p11;q21) translocation. The BCL6 gene was rearranged at a point within the first intron, and cloning of the rearranged BCL6 revealed unidentified sequences juxtaposed to the 5' side of the gene. The isolated clones were mapped to 16p11.2 by high resolution fluorescence in situ chromosomal hybridization. Thus, the YM cells carried a 3q27 translocation involving 16p11.2 as a partner. Chromosome painting of metaphase spreads confirmed that the YM cells had both t(2;18) and t(3;16). Northern blot analysis using a fragment immediately adjacent to the breakpoint on 16p11.2 revealed transcriptional activity within this locus. The YM cells expressed abundant transcripts with aberrant sizes from BCL2 and BCL6, indicating deregulated overexpression of the two genes resulting from the t(2;18) and t(3;16). The YM cell line will therefore be useful to study whether BCL2 and BCL6 genes collaborate in the pathogenesis of B-NHL.

Base Sequence↗

PubMed1998

Clinical significance of HLA-DRB1*0410 in Japanese patients with idiopathic thrombocytopenic purpura.

We performed HLA-A, -B, and -C antigen and -DR DNA typing in 111 Japanese patients with idiopathic thrombocytopenic purpura (ITP). DRB1*0410 was significantly increased in ITP patients compared with healthy controls (relative risk = 9.52, P < .05), but the other DRB1*04 alleles showed no significant differences. On HLA-DR serotyping, patients with Vogt-Koyanagi-Harada disease (VKH) had a high frequency of DR4, so we compared the frequencies of DRB1*04 suballeles between ITP and VKH. The high frequency of DRB1*04 was dependent on DRB1*0405 in VKH, but on DRB1*0410 in ITP. Plasma autoantibodies were studied in 111 patients using a microtiter well assay. Thirty-six patients had anti-GPIIb/IIIa autoantibodies, and antibody positivity was associated with HLA-DR4 (29 of 36, 80.6% v 28 of 75, 37.3%) but not with DRB1*0410. When HLA-DR4 and DRB1*0410 were compared between patients with a good or poor response to prednisolone, HLA-DR4 was decreased and DRB1*0410 was significantly decreased (chi2 = 11.455, P < .01) in patients with a good response. In conclusion, this study showed that genetically determined factors influence the course of ITP. However, our findings should be considered preliminary because of possible racial differences in HLA status between Japanese and other ITP patients.

Adult↗