Search PubMed⌕ Search

Biomedical subjects

S Fukuhara

Publications and source records attributed to S Fukuhara.

At least 55 records · Page 3Linked to original sources
PubMed2001

Platelet activation markers and soluble adhesion molecules in patients with systemic lupus erythematosus.

We assessed the role of platelet activation markers (PMPs, Annexin V and CD62P on activated platelets), cytokines (IL-1 beta, IL-4, IL-6, IFN- gamma, GM-CSF, and TNF alpha ), and soluble factors (sIL-2R, TM, sHLA-1, beta(2) -m, sVCAM-1, sPECAM-1, sP-selectin and sE-selectin) in vascular damage related to SLE. There were differences in the levels of PMPs and platelet activation markers between the SLE patients and controls (PMPs: 493+/-82 vs. 328+/-36, p<0.05; plt-CD62P; 8.5%+/-1.2 % vs. 4.6%+/-0.7 %, p<0.05; plt-Annexin V: 11.3%+/-2.1 % vs. 4.9%+/-0.6 %, p<0.01). There were no differences in the levels of IFN- gamma between the groups. However, the levels of IL-1 beta, IL-4, IL-6, GM-CSF, TNF alpha, and soluble factors were higher in the SLE patients than in the controls. The levels of IL-4, IL-6, beta2 -m, sIL-2R, sVCAM-1, sP-selectin, and sE-selectin in SLE patients with elevated sTM levels were higher than those in the SLE patients without elevated sTM levels. On the other hand, elevations of sIL-2R, sVCAM-1, and sP-selectin were not found in patients with Behçet disease or rheumatoid arthritis. The levels of platelet CD62P, platelet annexin V, and PMP were significantly elevated in high-sTM patients. These findings suggest the possibility that activated platelets and cytokines participate in the pathogenesis of SLE in patients with elevated sTM levels.

Adult↗
PubMed2001

[Systemic inflammatory response syndrome triggered by necrotizing cholecystitis after treatment of underlying low titer cold agglutinin disease].

In April 1996, a 77-year-old man initially presented with fever, rash and polyarthralgia, and was diagnosed as having low titer cold agglutinin disease with acute hemolytic anemia. The patient's condition and laboratory findings improved after administration of corticosteroid (prednisolone 60 mg). In June 1996, however, he developed acute cholecystitis and died due to sepsis, disseminated intravascular coagulation and multiple organ failure. During the course, the levels of inflammatory cytokines such as TNF-alpha and IL-6 were correlated with the pathology, and the disease was diagnosed as systemic inflammatory response syndrome (SIRS). Autopsy revealed necrotizing cholecystitis, erythrophagocytosis in the liver, and cytomegalovirus infection in the lung and gall bladder. This was considered to be a rare case of low titer cold agglutinin disease complicated by SIRS.

Aged↗
PubMed2001

Characteristic magnetic resonance imaging for neurological assessment in HELLP syndrome with eclampsia: a case report.

HELLP syndrome is a complication of pregnancy characterized by hemolytic anemia, elevated liver enzymes, and low platelets. We describe a patient who suffered a generalized tonic seizure as a clinical onset. Magnetic resonance imaging (MRI) of the brain showed high intensity lesions on T2-weighted images and low- and iso- intensity on T1-weighed images. The patient fully recovered and on follow-up MRI the abnormal lesions were almost totally resolved. The sensitivity and specificity of MRI is useful in distinguishing this complication of pregnancy from cerebral apoplexy, brain tumor, epilepsy and other causes.

Adult↗
PubMed2001

[High-dose therapy and peripheral blood stem cell transplantation for patients with aggressive non-Hodgkin's lymphoma remaining in initial remission: results of a feasibility study].

High-dose therapy with peripheral blood stem cell transplantation (HDT/PBSCT) was performed as one aspect of front-line therapy in patients with poor-risk aggressive non-Hodgkin's lymphoma (high-intermediate/high risk) according to the age-adjusted international prognostic index (aaIPI). Twenty-nine patients were enrolled in this study between November 1994 and March 1999. CHOP + etoposide (CHOP-E) was used as an initial chemotherapy and as a chemotherapy agent for the purpose of cell harvesting. Peripheral blood stem cells were harvested from 17 patients, and HDT with CEC (carboplatin, etoposide, cyclophosphamide)/PBSCT was performed in 11 patients. Eighteen patients dropped out, including five for whom CHOP-E therapy was ineffective and 5 who did not give consent for cell harvesting or HDT/PBSCT. CHOP-E therapy produced complete remission (CR) in 15 out of 26 patients (58%) after discounting the 3 who were ineligible among the 29 who were initially enrolled. The median observation period after PBSCT in the 11 patients who underwent HDT/PBSCT was 25 months (3 to 50 months), and the 3-year disease-free survival rate was 73%. No serious complications associated with the transplantation were observed. We were able to confirm the feasibility and safety of HDT/PBSCT as one form of front-line therapy for aggressive non-Hodgkin's lymphoma in patients under 60 years of age.

Adolescent↗
PubMed2000

Leukemia-associated Rho guanine nucleotide exchange factor (LARG) links heterotrimeric G proteins of the G(12) family to Rho.

A putative guanine nucleotide exchange factor (GEF), termed leukemia-associated RhoGEF (LARG), was recently identified upon fusion to the coding sequence of the MLL gene in acute myeloid leukemia. Although the function of LARG is still unknown, it exhibits a number of structural domains suggestive of a role in signal transduction, including a PDZ domain, a LH/RGS domain, and a Dbl homology/pleckstrin homology domain. Here, we show that LARG can activate Rho in vivo. Furthermore, we present evidence that LARG is an integral component of a novel biochemical route whereby G protein-coupled receptors (GPCRs) and heterotrimeric G proteins of the G alpha(12) family stimulate Rho-dependent signaling pathways.

Cloning, Molecular↗
PubMed2000

SPECs, small binding proteins for Cdc42.

The Rho GTPase, Cdc42, regulates a wide variety of cellular activities including actin polymerization, focal complex assembly, and kinase signaling. We have identified a new family of very small Cdc42-binding proteins, designated SPECs (for Small Protein Effector of Cdc42), that modulates these regulatory activities. The two human members, SPEC1 and SPEC2, encode proteins of 79 and 84 amino acids, respectively. Both contain a conserved N-terminal region and a centrally located CRIB (Cdc42/Rac Interactive Binding) domain. Using a yeast two-hybrid system, we found that both SPECs interact strongly with Cdc42, weakly with Rac1, and not at all with RhoA. Transfection analysis revealed that SPEC1 inhibited Cdc42-induced c-Jun N-terminal kinase (JNK) activation in COS1 cells in a manner that required an intact CRIB domain. Immunofluorescence experiments in NIH-3T3 fibroblasts demonstrated that both SPEC1 and SPEC2 showed a cortical localization and induced the formation of cell surface membrane blebs, which was not dependent on Cdc42 activity. Cotransfection experiments demonstrated that SPEC1 altered Cdc42-induced cell shape changes both in COS1 cells and in NIH-3T3 fibroblasts and that this alteration required an intact CRIB domain. These results suggest that SPECs act as novel scaffold molecules to coordinate and/or mediate Cdc42 signaling activities.

3T3 Cells↗
PubMed2000

Signaling from G protein-coupled receptors to ERK5/Big MAPK 1 involves Galpha q and Galpha 12/13 families of heterotrimeric G proteins. Evidence for the existence of a novel Ras AND Rho-independent pathway.

The regulation of gene expression by cell surface receptors often involves the stimulation of signaling pathways including one or more members of the MAPK superfamily of serine-threonine kinases. Upon their activation in the cytosol, MAPKs can translocate to the nucleus and affect the activity of a variety of transcription factors. Recently, it has been observed that a novel member of the MAPK superfamily, ERK5, can be potently activated by transforming G protein-coupled receptors (GPCRs) and that ERK5 participates in the regulation of c-jun expression through the activation of MEF2 transcription factors. How cell surface receptors, including GPCRs, stimulate ERK5 is still poorly understood. In this study, we have used transiently transfected COS-7 cells to begin delineating the biochemical route linking GPCRs to ERK5. We show that receptors that can couple to the G(q) and G(12/13) families of heterotrimeric G proteins, m1 and thrombin receptors, respectively, but not those coupled to G(i), such as m2 receptors, are able to regulate the activity of ERK5. To investigate which heterotrimeric G proteins signal to ERK5, we used a chimeric system by which Galpha(q)- and Galpha(13)-mediated signaling pathways can be conditionally activated upon ligand stimulation. Using this system, as well as the expression of activated forms of G protein subunits, we show that the Galpha(q) and Galpha(12/13) families of heterotrimeric G proteins, but not the Galpha(i), Galpha(s), and betagamma subunits, are able to regulate ERK5. Furthermore, we provide evidence that the stimulation of ERK5 by GPCRs involves a novel signaling pathway, which is distinct from those regulated by Ras and Rho GTPases.

Animals↗
PubMed2000

Platelet-derived microparticles in patients with arteriosclerosis obliterans: enhancement of high shear-induced microparticle generation by cytokines.

We evaluated the plasma concentrations of cytokines and platelet-derived microparticles in patients with arteriosclerosis obliterans and studied the effect of cytokines on platelet-derived microparticle generation under high shear stress. Interleukin-6 levels peaked at 48 hours after vascular surgery, while thrombopoietin started to increase at 24 to 48 hours postoperatively and peaked on the seventh day. Platelet activation markers were increased in the arteriosclerosis obliterans patients preoperatively. Levels of P-selectin and CD63 both increased further, peaking at 6 to 24 hours postoperatively. Platelet-derived microparticle levels were also increased preoperatively. At 6 hours postoperatively, the plasma level of platelet-derived microparticles was significantly increased. Plasma platelet-derived microparticle level was lower at 12 hours but only returned to the preoperative value at 7 days after grafting. There was a difference in the platelet-derived microparticle level at 7 days between patients with or without antiplatelet therapy (cilostazol). The effect of cytokines on platelet activation under high shear stress was also studied. Interleukin-6 and thrombopoietin enhanced both P-selectin expression and platelet-derived microparticle generation under high shear stress. These results suggest that platelet-derived microparticles are released by platelet activation after vascular grafting when certain cytokines increase under high shear stress and that antiplatelet therapy may reduce platelet-derived microparticle levels postoperatively.

Aged↗
PubMed2000

A novel role for phosphatidylinositol 3-kinase beta in signaling from G protein-coupled receptors to Akt.

The protein kinase Akt plays a central role in a number of key biological functions including protein synthesis, glucose homeostasis, and the regulation of cell survival or death. The mechanism by which tyrosine kinase growth factor receptors stimulate Akt has been recently defined. In contrast, the mechanism of activation of Akt by other cell surface receptors is much less understood. For G protein-coupled receptors (GPCRs), conflicting data suggest that these receptors stimulate Akt in a cell type-specific manner by a yet to be fully elucidated mechanism. Here, we took advantage of the availability of cells, where Akt activity could not be enhanced by agonists acting on this large family of cell surface receptors, such as NIH 3T3 cells, to investigate the pathway linking GPCRs to Akt. We present evidence that expression of phosphatidylinositol 3-kinase (PI3K) beta is necessary and sufficient to transmit signals from G proteins to Akt in these murine fibroblasts and that the activation of PI3Kbeta may represent the most likely mechanism whereby GPCRs stimulate Akt, as the vast majority of cells do not express PI3Kgamma, a known G protein-sensitive PI3K isoform. Furthermore, available evidence indicates that GPCRs activate Akt by a pathway distinct from that utilized by growth factor receptors, as it involves the tyrosine phosphorylation-independent activation of PI3Kbeta by G protein betagamma dimers.

3T3 Cells↗
PubMed2000

Cbl-b regulates the CD28 dependence of T-cell activation.

Whereas co-stimulation of the T-cell antigen receptor (TCR) and CD28 triggers T-cell activation, stimulation of the TCR alone may result in an anergic state or T-cell deletion, both possible mechanisms of tolerance induction. Here we show that T cells that are deficient in the adaptor molecule Cbl-b (ref. 3) do not require CD28 engagement for interleukin-2 production, and that the Cbl-b-null mutation (Cbl-b(-/-)) fully restores T-cell-dependent antibody responses in CD28-/- mice. The main TCR signalling pathways, such as tyrosine kinases Zap-70 and Lck, Ras/mitogen-activated kinases, phospholipase Cgamma-1 and Ca2+ mobilization, were not affected in Cbl-b(-/-) T cells. In contrast, the activation of Vav, a guanine nucleotide exchange factor for Rac1/Rho/CDC42, was significantly enhanced. Our findings indicate that Cbl-b may influence the CD28 dependence of T-cell activation by selectively suppressing TCR-mediated Vav activation. Mice deficient in Cbl-b are highly susceptible to experimental autoimmune encephalomyelitis, suggesting that the dysregulation of signalling pathways modulated by Cbl-b may also contribute to human autoimmune diseases such as multiple sclerosis.

Adaptor Proteins, Signal Transducing↗
PubMed2000

Serum levels of soluble CD30 in autologous peripheral blood stem cell transplantation.

High-dose chemotherapy with peripheral blood stem cell transplantation (PBSCT) has become an important method of treatment for hematological and solid tumors. We examined levels of interleukin(IL)-4, interferon (IFN)gamma, soluble (s) CD30, and sIL-2 receptor (R) before and after autologous PBSCT, and compared findings for PBSCT with those for bone marrow transplantation (BMT). We found significantly higher IL-4 levels 1 and 3 weeks after PBSCT than before PBSCT, while IFNgamma levels remained almost unchanged after PBSCT. IFNgamma levels were increased 3 weeks after BMT, although no increase in IL-4 level was observed. The serum sCD30 level was significantly higher 3 weeks after PBSCT, but not following BMT. For 34 samples on days 0 and 21 from 17 patients undergoing PBSCT, a strong correlation was observed between sCD30 and sIL-2R levels (r = 0.43, P < 0.01). However, no significant correlation between sCD30 and sIL-2R levels was found for BMT patients. These findings suggest that sCD30 is a useful marker for evaluating immunological activity following autologous PBSCT, and that the immunological conditions after autologous PBSCT may be associated with helper-T-cell-2-type immune responses.

Adult↗
PubMed2000

A Japanese propositus with D-- phenotype characterized by the deletion of both the RHCE gene and D1S80 locus situated in chromosome 1p and the existence of a new CE-D-CE hybrid gene.

In a family study of a Japanese propositus with the D-- phenotype, the serological data of her D-- phenotype and those of her parents were discrepant. Gene analysis of the propositus showed a gross deletion of the RHCE gene and a new rearrangement of RHCE to yield the CE-D-CE hybrid. It was demonstrated that the hybrid CE-D-CE gene consisted of exon 1 from the RHCE gene, followed by exons 3 to 7 from the RHD gene and exons 8 to 10 from the RHCE gene. However, whether or not exon 2 of the RHD or the RHCE gene was contained in the CE-D-CE gene remained unclear. Moreover, spacer analysis between both RH genes and the family study suggested that the D-- gene complex from the paternal and maternal sides consisted of only the CE-D-CE hybrid gene and a single RHD gene, respectively. For the purpose of confirming the parent-child relationship, a paternity test using DNA fingerprint and polymerase chain reaction (PCR) analysis at the D1S80 locus were performed. DNA fingerprints with two kinds of DNA minisatellite probes (33.15 and 33.6) confirmed that the parent-child relationship in the D-- propositus was compatible. However, in the present case, at the D1S80 locus, the PCR product derived from the mother was lacking, thereby negating a parent-child relationship. It is probable that the RH genes and D1S80 locus exist in close proximity, because they are situated in chromosomes 1p 34.3-36.1 and 1p 36.1-36.3, respectively. These data suggested that at the stage of gametogenesis, both the RHCE gene and the D1S80 locus from the maternal side may have been deleted, thereby producing the D-- gene complex.

Chimera↗
PubMed2000

Plasma-soluble Fas (APO-1, CD95) and soluble Fas ligand in immune thrombocytopenic purpura.

We investigated the levels of various cytokines and soluble factors in ITP patients, in order to determine the influence of these factors on the pathogenesis of ITP. We found increases in IL-2, IL-6, IFN-gamma, and M-CSF levels in ITP patients compared with those in healthy individuals. On lymphocyte phenotype analysis, we found no clear difference in total T cell population (CD2+ CD19- cells) or cytotoxic T cell frequency (CD8+ CD11b- cells) between these two groups. The frequency of helper/inducer T cells (CD4+ CD8- cells) was decreased in ITP patients. There was a significant increase in activated T cells (CD3+ HLA-DR+ cells) in ITP patients. Furthermore, frequencies of NK cells of potent activity (CD16+ CD56+ cells) were significantly elevated in ITP patients. Seventeen of the 54 ITP patients (31.5%) had elevated levels of sFas, and 11 of the 54 patients (20.4%) of sFasL. In addition, a significant increase of sFasL was observed in sFas-positive ITP patients, and in these patients the sFasL level was correlated with that of sFas (r = 0.687, p < 0.01). We found significant increases in IL-2 and sIL-2R levels in sFas-positive ITP patients. For other factors examined, however, there were no differences in level between sFas-positive and -negative ITP patients. Percentages of activated T cells (CD3+ and HLA-DR+ cells) and NK cells (CD16+ and CD56+ cells) were significantly higher in sFas-positive ITP patients than in sFas-negative ITP patients. These findings suggests that the pathogenesis of ITP includes alteration of the Fas/FasL pathway.

Adult↗
PubMed2000

Elevated MLF1 expression correlates with malignant progression from myelodysplastic syndrome.

MLF1 is a novel protein identified as the NPM-MLF1 chimeric protein produced by a t(3;5)(q25.1;q34) chromosomal translocation, which is associated with myelodysplastic syndrome (MDS), often prior to acute myeloid leukemia (AML), except for M3. The clinical features of t(3;5)-positive myeloid disorders suggest that this chimeric protein is involved in dysregulation of progenitor cells with the capability to differentiate into multiple lineages. So far, involvement of wild-type MLF1 in hematopoiesis or in leukemogenesis has not been fully investigated. In the present study, 65 patients with AML and 44 patients with MDS were tested for the expression of MLF1 using the quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) method. A significantly higher level of MLF1 expression (ratio of MLF1/beta-actin mRNA >0.4) was readily detected in seven of 65 patients with de novo AML, three of 12 with post-MDS AML and seven of 44 with MDS, but not in any patients with ALL (n = 18). According to the FAB classification, high levels of MLF1 were found in patients with relatively immature subtypes of AML (M1, M2, M6 and M7) and high risk MDS (RAEB and RAEB-T). These findings indicate that the pattern of MLF1 expression is identical to the clinical morphology appearing in the t(3;5)-positive myeloid disorders and is correlated to the MDS-associated AML and transformation phase of MDS in t(3;5)-negative myeloid disorders. A CD34+ population of normal bone marrow cells preferentially expressed MLF1 with obviously decreasing levels of expression during maturation. Therefore, MLF1 normally functions in multi-potent progenitor cells and its dysregulation may take part in leukemogenesis from MDS.

Acute Disease↗
PubMed2000

Significance of chemokines and activated platelets in patients with diabetes.

Levels of platelet-derived microparticles (PMPs), platelet activation markers (P-selectin expressed on, or annexin V binding to, platelets (plt:P-selectin or plt:annexin V, respectively)), chemokines (IL-8, monocyte chemotactic peptide-1 (MCP-1), and regulated on activation normally T-cell expressed and secreted (RANTES)), and soluble P- and E-selectins were compared in peripheral blood from diabetic and control patients in order to develop a better understanding of their potential contribution to diabetic vascular complications. Significant increases were found for PMPs, plt:P-selectin, MCP-1, RANTES and soluble P- and E-selectins in diabetic individuals, whereas IL-8 levels were similar. Furthermore, after ticlopidine treatment, most of these factors receded to baseline levels observed in non-diabetic patients. Our findings indicate that ticlopidine might be able to prevent or reduce vascular complications in diabetic patients.

Adult↗