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Biomedical subjects

S Asano

Publications and source records attributed to S Asano.

At least 271 records · Page 15Linked to original sources
PubMed1995

[The effects of recombinant human granulocyte colony-stimulating factor on protracted neutropenia in patients with acute myelogenous leukemia. (rG.CSF Clinical Study Group)].

A clinical study to investigate the efficacy and safety of recombinant human G-CSF (rG.CSF) was performed in patients with acute myelogenous leukemia who had had protracted neutropenia. The drug was administered d.i.v. at a dose of 5 micrograms/kg. Sixty-four patients entered the study, of whom 61 patients were evaluable for safety and 58 patients evaluable for efficacy. The treatment produced an early recovery in neutrophil count in the patients who had had protracted neutropenia (< 1,000/microliters) of over 10 days. Among relapsed cases and cases showing > 20% blasts in the bone marrow, many showed blast stimulation in response to rG.CSF, suggesting difficulty in attaining complete remission by subsequent chemotherapy in such cases. The present data indicates that it is desirable to use the drug in lower-blast-count states in order to attain safe and sufficient therapeutic effects in patients with acute myelogenous leukemia who have had protracted neutropenia.

Adolescent↗
PubMed1995

[A randomized controlled study of rG.CSF in patients with neutropenia after induction therapy for acute myelogenous leukemia. (rG.CSF Clinical Study Group)].

A randomized treated/non-treated study of rG.CSF (5 micrograms/kg/d, d.i.v.) in patients with acute myelogenous leukemia was conducted to assess its efficacy on fever (> or = 38 degrees C) or documented infection after induction therapy. Of 95 patients enrolled, 46 patients were evaluable for safety and 43 for efficacy in the treated group of 47 patients while 37 of 48 patients were eligible for data analysis in the untreated group. Mare patients showed a recovery in the blood neutrophil count (to > 1,000/microliters) during rG.CSF treatment (14 days) than in the non-treated group (p = 0.039) while the number of febrile patients and duration of fever did not significantly differ between the two groups. The treatment with rG.CSF enabled an early recovery in neutrophil count in the patients with neutropenia and overt signs of infection after induction therapy, but there was no hastened allevistion of symptoms of infection in these patients.

Adolescent↗
PubMed1995

[A randomized double-blind controlled study of recombinant human granulocyte colony-stimulating factor in patients with neutropenia induced by consolidation chemotherapy for acute myeloid leukemia. (rG.CSF clinical study group)].

A multicenter, randomized, double-blind controlled study was performed to evaluate the efficacy and safety of recombinant human granulocyte colony-stimulating factor (rG.CSF) in reducing infectious morbidity and neutropenia induced by consolidation chemotherapy for acute myeloid leukemia (AML). One hundred and twenty-four eligible patients were randomized to receive either rG.CSF (5 micrograms/kg/d d.i.v.; 59 patients) or placebo (65 patients) for 14 days from the day after chemotherapy. All of them were included in the safety analysis, while 57 patients receiving rG.CSF and 64 patients receiving placebo were included in the efficacy analysis. The duration of neutropenia as well as the incidence of fever and febrile neutropenia, and frequency of antibiotic therapy required, were all significantly reduced in the rG.CSF group. No serious adverse reactions were encountered; there was no significant difference between the two groups in terms of incidence of adverse events. These results demonstrate that rG.CSF is beneficial to alleviate neutropenic episodes induced by consolidation chemotherapy in patients with AML.

Adolescent↗
PubMed1995

Differential effects of the immunosuppressants cyclosporin A, FK506 and KM2210 on cytokine gene expression.

Cyclosporin A (CsA) inhibited interleukin 2 (IL-2), IL-3, interferon gamma (IFN gamma), GM-CSF and tumor necrosis factor alpha (TNF alpha) mRNA expression in spleen cells stimulated with concavalin A (Con A) when determined by the semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR) method. FK506 which has a similar immunosuppressive mechanism to that of CsA also showed the same inhibitory effects except for decreased IL-5 and IL-6 mRNA expression. In contrast, both CsA and FK506 enhanced transforming growth factor beta (TGF beta) and IL-1 beta mRNA expression. Another immunosuppressant KM2210 did not show any inhibitory effects on cytokine gene expression but rather enhanced IL-10, IL-6, TGF beta and IL-1 mRNA expression, thus suggesting that KM2210 has a completely different immunosuppressive mechanism from that of CsA and FK506. Anti-TFG beta 1 antibody abrogated the suppression by KM2210 of BALB/c anti-3H/He mixed lymphocyte reaction (MLR) whereas this antibody did not abrogate the suppression by CsA and FK506 of BALB/c anti-C3H/He MLR. These results indicate that TGF beta is one of the major cytokines in KM2210 immunosuppression, in addition to IL-10, but not in immunosuppression by CsA and FK506.

Animals↗
PubMed1995

Bone marrow stromal cells produce and respond to activin A: interactions with basic fibroblast growth factor and platelet-derived growth factor.

Activin A, a homodimer of the beta A-chain, regulates hematopoiesis. We recently reported that murine bone marrow (BM) stromal cells, ST2 and MC3T3-G2/PA6, produce activin A [16]. Basic fibroblast growth factor (bFGF) and platelet-derived growth factor (PDGF), potent mitogens of BM stromal cells, induced a rapid increase in beta A-chain mRNA levels and activin secretion in these cells. Cycloheximide (CHX) did not inhibit the increases in beta A-chain mRNA levels, suggesting that these growth factors directly stimulate beta A-chain gene expression. Furthermore, activin A stimulated mitogenesis in ST2 cells, by itself and with bFGF and PDGF. Consistent with this observation, we detected mRNAs of activin A receptors in the murine stromal cells. These findings suggest that BM stromal cells, stimulated by bFGF and PDGF, produce activin A, which may stimulate stromal cells themselves in concert with these peptide growth factors.

Activin Receptors↗
PubMed1994

Identification of a breakpoint cluster region 3' of the ribophorin I gene at 3q21 associated with the transcriptional activation of the EVI1 gene in acute myelogenous leukemias with inv(3)(q21q26).

Structural alterations occur in the long arm of chromosome 3 in approximately 2% of patients with acute myelogenous leukemia (AML) or myelodysplastic syndrome (MDS). The major alterations are inv(3)(q21q26) and t(3:3)(q21;q26) and are often classified as the 3q21q26 syndrome. We previously reported that the EVI1 gene is transcriptionally activated in AMLs with t(3;3)(q21;q26) and inv(3)(q21q26) and that the chromosomal breakpoints at 3q26 in the translocations were 5' of the EVI1 gene, whereas the breakpoints in the inversion cases were 3' of the gene. In these studies, four additional cases of AML with inv(3)(q21q26) are shown to express the EVI1 gene and to have breakpoints 3' of the gene. To characterize the 3q21 breakpoint region, cosmid and phage clones were isolated that cover approximately 100 kb. At 3q21, the breakpoints for both AMLs with t(3;3)(q21;q26) and inv(3)(q21q26) were found to cluster over a region of approximately 50 kb downstream of the Ribophorin I gene. The results indicate a common mechanism for the translocations and inversions and support the hypothesis that the transcriptional activation of the EVI1 gene is mediated by enhancer elements associated with the Ribophorin I gene.

Adult↗
PubMed1994

Rifampicin prevents the aggregation and neurotoxicity of amyloid beta protein in vitro.

The aggregation and cerebral deposition of amyloid beta protein (A beta), which is a major component of senile plaques in Alzheimer's disease (AD) brains, is believed to be involved in the pathogenesis of AD. Inhibition of A beta aggregation would seem to be a promising strategy for the treatment of AD. Here, we show that rifampicin, which is an antibiotic widely used in the treatment of tuberculosis and leprosy, inhibited the aggregation and fibril formation of synthetic A beta 1-40 peptide in a dose-dependent manner at reasonable concentrations. Furthermore, rifampicin was found to prevent A beta 1-40-induced neurotoxicity on rat pheochromocytoma PC12 cells. Rifampicin may have therapeutic potential as an agent for inhibiting the initial step of amyloid formation in AD.

Adrenal Gland Neoplasms↗
PubMed1994

Adhesion of NFS-60 myeloid leukemia cells to MC3T3-G2/PA6 stromal cells induces granulocyte colony-stimulating factor production.

To examine the interaction between immature myeloid cells and stromal cells in the induction of granulocyte colony-stimulating factor (G-CSF) production, stromal cells of the MC3T3-G2/PA6 (PA6) murine cell line, which has preadipocyte characteristics and can support hematopoiesis, were cocultured with various myeloid cell lines and G-CSF mRNA expression was examined by Northern and reverse transcriptase-polymerase chain reaction analyses. A significant amount of G-CSF mRNA was induced by the culture of an interleukin-3/G-CSF-dependent murine myeloid leukemia cell line, NFS-60, on PA6 stromal cells for 16 hours. Using a G-CSF-dependent subline of DA-1 (DA-1N), the biologic activity of G-CSF was also detected in PA6/NFS-60 coculture supernatants, but not in the culture supernatant of PA6 or NFS-60 alone. Direct contact of NFS-60 cells with the PA6 stromal layer was essential for the induction of G-CSF mRNA, as indicated by the following observations: (1) NFS-60 cells efficiently adhered to PA6 cells; (2) medium conditioned by NFS-60 cells did not contain the activity to induce G-CSF mRNA in PA6 cells; and (3) induction of G-CSF mRNA was not observed when NFS-60 cells were separated from PA6 cells by a microporous membrane (0.45-microns pore size). Several other myeloid cell lines, including FDC-P2, 32Dcl3, WEHI-3, and DA-1, did not induce G-CSF mRNA expression after the coculture with PA6 cells, although significant numbers of these cells adhered to PA6 cells. Therefore, NFS-60 cells may express or overexpress a molecule that is involved in adhesion-mediated induction of G-CSF production.

Animals↗
PubMed1994

Regulation of recombinant human granulocyte colony-stimulation factor production using herpes simplex virus 1 thymidine kinase gene.

For chronic neutropenic patients requiring long-term injection of recombinant human granulocyte colony-stimulating factor (rhG-CSF), a cellular transplantation system that can produce this cytokine stably and deliver it in a regulatory manner would be advantageous. In this study we aimed at developing a regulation system at cellular level using suicide vectors. We introduced the herpes simplex virus type 1 thymidine kinase (HSV-TK) gene into the rhG-CSF-producing NIH3T3 cells and examined if ganciclovir (GCV) treatment of the cells could control the rhG-CSF production in vitro. The cells transfected with the HSV-TK gene showed a > 100-fold increase in sensitivity to GCV compared with the parent cells, and the median inhibitory dose of GCV to the transfected cells was less than 1.6 microM. The total amount of rhG-CSF production by these cells was strongly suppressed by GCV treatment. This regulatory method may be applicable to cytokine supplement gene therapy.

Ganciclovir↗
PubMed1994

An intrinsic guanine nucleotide exchange inhibitor in Gi2 alpha. Significance of G-protein self-suppression which antagonizes receptor signal.

The alpha subunit of Gi2 (Gi2 alpha) is a member of the heterotrimeric G protein family, which transduces receptor signals as a proto-oncogene product. We have found a novel self-suppressive region in Gi2 alpha near its C terminus. A polypeptide consisting of residues 338-352 of Gi2 alpha (Gi2 alpha-339-352) antagonizes receptor- and receptor peptide-stimulated Gi2 alpha activation, without affecting basal activity. Antagonism by Gi2 alpha-338-352 is attributable to an interaction with activated Gi2 alpha, which is not competitive with receptor polypeptides. Combined with the reports suggesting the presence of self-suppressive domains in a juxta-C-terminal portion of Gi2 alpha and G(o) alpha, this study supports the hypothesis that Gi2 alpha-338-352 constitutes an intrinsic guanine nucleotide exchange inhibitor, which in turn antagonizes receptor stimulation, suggesting that G proteins are activated by receptors through relaxation of a self-suppressive conformation.

Amino Acid Sequence↗
PubMed1994

Multiple DNA conformational changes induced by an initiator protein precede the nicking reaction in a rolling circle replication origin.

The core origin for plus strand DNA replication of filamentous bacteriophage f1 binds the initiator protein (gpII), which subsequently introduces a specific nick in the plus strand. The core origin consists of a nicking region and a binding region. The binding of gpII occurs in two steps, forming a binding intermediate (complex I) and a functional complex for nicking (complex II). Results of gel retardation experiments using circularly permuted DNA fragments and direct visualization by electron microscopy show that gpII induces successive bends within the binding region upon formation of the complexes. We show that gpII binding induces duplex melting in the nicking region using KMnO4 modification of unpaired thymidine residues as a probe for melting. Origin binding occurred in the absence of superhelicity of DNA and Mg2+, whereas duplex melting required superhelical DNA, but not Mg2+. Deletion analyses indicated that hypothetical formation of a cruciform around the nicking site is not necessary for either melting or nicking. A mutation in gpII resulted in stimulation of duplex melting and nicking without showing obvious effects on bending. This suggests that the mechanism of melting involves local interaction between gpII and the nicking region. Furthermore, using synthetic oligonucleotide substrates, we show that the nicking reaction takes place efficiently when the nicking region is single-stranded and the binding region is double-stranded. These results indicate that the nicking reaction is preceded by an ordered series of protein-induced DNA-conformational changes: successive bending of the origin upon gpII binding, followed by duplex melting that requires negative superhelicity.

Base Sequence↗
PubMed1994

Racemization of Asp23 residue affects the aggregation properties of Alzheimer amyloid beta protein analogues.

The beta proteins in amyloid deposits of Alzheimer's disease have been found to be racemized and/or isomerized at their Asp residues (Roher, A. E., Lowenson, J. D., Clarke, S., Wolkow, C., Wang, R., Cotter, R. J., Reardon, I. M., Zurcher-Neely, H. A., Heinrikson, R. L., Ball, M. J., and Greenberg, B. D. (1993) J. Biol. Chem. 268, 3072-3083). To elucidate the effect of racemization on the aggregation properties of beta proteins, we synthesized four beta protein analogues in which D-Asp was substituted for L-Asp residues, i.e. normal beta 1-35, [D-Asp7]beta 1-35, [D-Asp23]beta 1-35, and [D-Asp7,D-Asp23]beta 1-35. The aggregation and fibril formation of the peptides were examined by means of spectrophotometry, sodium dodecyl sulfatepolyacrylamide gel electrophoresis (SDS-PAGE), and electron microscopy. Of the four peptides, [D-Asp23]beta 1-35 showed the earliest increase in turbidity and appearance of a smear in SDS-PAGE. This was followed by [D-Asp7,D-Asp23]beta 1-35 and normal beta 1-35. [D-Asp7]beta 1-35 was considerably delayed in showing these signs of aggregation. Corresponding with the increase in turbidity and the appearance of a smear in SDS-PAGE, fibril formation was observed in electron microscopy. These results reveal that the aggregation properties of beta 1-35 peptides are affected by racemization of their Asp residues depending on their position. Racemization at amino acid position 23 accelerated the peptide aggregation and fibril formation, while that at position 7 slowed down this reaction. This suggests that the site-specific racemization of beta protein may be involved in the amyloid fibril formation in Alzheimer's disease.

Alzheimer Disease↗