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Biomedical subjects

K Muta

Publications and source records attributed to K Muta.

At least 55 records · Page 3Linked to original sources
PubMed1999

Effect of topical amosulalol on tissue circulation in the optic nerve head.

The effect of topical 0.1% amosulalol on tissue circulation in the albino rabbit optic nerve head (ONH) was investigated using a laser speckle tissue circulation analyzer. Amosulalol was administered into one eye twice daily for 20 days, and vehicle was administered into the other eye in a masked, randomized manner. Intraocular pressure (IOP) was measured every 5 days. The normalized blur value (NB), a quantitative index of tissue blood flow velocity in the ONH, was measured before treatment and 2 hours after the last instillation on day 20. The IOP was also measured at 5-day intervals. Amosulalol decreased IOP by approximately 2 mmHg in the treated eyes (P < 0.01). There was no significant difference in NB between eyes before the first instillation, whereas NB was significantly greater (by approximately 16%) in the amosulalol-treated eye than in the control eye after completion of instillations (P < 0.01). The difference between NB after completion of instillations and that before the first instillation was significantly greater in the ONH of the amosulalol-treated eye than in the contralateral control eye (P < 0.01). Twice-daily instillation of 0.1% amosulalol for 20 days induced a significant increase in tissue blood velocity in the ipsilateral ONH in albino rabbits.

Administration, Topical↗
PubMed1999

Thiazolidinedione induces apoptosis and monocytic differentiation in the promyelocytic leukemia cell line HL60.

Thiazolidinedione (TZD) is known to be a potent activator of peroxisome proliferator-activated receptor gamma (PPARgamma), a nuclear receptor that constitutes a heterodimer with retinoid X receptor (RXR). Since a considerable amount of PPARgamma is expressed in various hematopoietic cells, the present study was undertaken to examine the effect of TZD in the absence or presence of LG100268, an RXR-selective ligand, on a cultured promyelocytic leukemia cell line, HL60. Treatment with TZD (25-50 microM troglitazone or pioglitazone) markedly suppressed cell proliferation of HL60. A cell cycle analysis revealed that the suppressive effect of troglitazone on HL60 cell proliferations was caused by G0/G1 cell cycle arrest as well as by an apoptotic effect. Treatment with the same concentration of troglitazone also induced the monocytic differentiation of HL60 cells. The apoptotic or the differentiating effect of TZD on HL60 cells was synergistically enhanced by the combined treatment with 1 microM LG100268, while LG100268 alone neither had an apoptotic nor a differentiating effect on HL60 cells. These results suggest that these actions are mediated through the nuclear receptor system constituted by the PPARgamma: RXR heterodimer.

Antineoplastic Agents↗
PubMed1999

Telomerase activity in myeloma cells is closely related to cell cycle status, but not to apoptotic signals induced by interferon-alpha.

Telomeres, G-rich structures at the ends of chromosomes are essential for maintaining chromosomal integrity. Most tumor cells contain telomerase, a ribonucleoprotein that elongates telomeric repeats, and it plays an essential role in indefinite proliferation. To better understand regulatory mechanisms of telomerase, in relationship with apoptosis and the cell cycle, we examined telomerase activity in PCM6, an interleukin-6 (IL-6)-responsive, interferon-alpha (IFN-alpha)-sensitive multiple myeloma cell line, using a PCR-based assay. When PCM6 cells were cultured in serum-free media, the addition of IFN-alpha resulted in apoptosis of the cells, but with no influence on telomerase activity. When IFN-alpha was added to the culture with serum plus rIL-6 after serum deprivation, G1-S transition was inhibited and telomerase activity was lower compare to findings in culture with no IFN-alpha. Dose response experiments of rIL-6 and IFN-alpha, and the measurement of telomerase activity of sorted cells in S-phase using CD71, demonstrated a higher activity of telomerase in the samples which contained a larger proportion of cells in S-phase. These data indicate that regulation of telomerase activity is closely related to cell cycle status, in particular cells in S-phase have an high telomerase activity. While telomeres play an important role in cellular senescence, the regulation of telomerase is independent from apoptotic signals induced by IFN-alpha in myeloma cells.

Apoptosis↗
PubMed1999

[Donor leukocyte transfusion in a patient with relapsed chronic myeloid leukemia after allogeneic bone marrow transplantation: analysis of natural killer cell activity and T-cell receptor repertoire in bone marrow T cells that exhibited graft-versus-leukemia activity].

Hematologic relapse of chronic myeloid leukemia developed in 37-year-old man 255 days after allogeneic bone marrow transplantation. The patient received a donor lymphocyte transfusion (DLT) twice at a dose of 5 x 10(6)/kg T cells. He achieved complete cytogenetic response (CCR) 14 weeks after DLT, and has remained in a CCR state for 17 months. Neither acute nor chronic graft-versus-host disease (GVHD) was observed. Natural killer (NK) cell activity was elevated. Also, analysis of the T cell receptor (TCR) repertoire disclosed oligoclonal expansion of T cells of the TCR V beta and J beta subfamilies. These observations provide evidence for the clonal expansion of allogeneic T cells that are capable of mediating antileukemic activity without causing GVHD.

Adult↗
PubMed1999

[Detection of t(3 ; 21) (q26 ; q22) with AML1/EVI1 mRNA during progression of myelodysplastic syndrome to acute myeloid leukemia].

A 74-year-old woman had myelodysplastic syndrome (MDS) in 1986. In June 1994, she suffered exacerbation of pancytopenia with no chromosomal abnormalities, but AML1/EVI1 chimeric mRNA was detected by RT-PCR. Two months later, an increase in bone marrow blasts (5%) was noted, and chromosomal analysis detected t(3 ; 21) (q26 ; 22), del(7) (q22), del(11) (q23). In 1995, the marrow blasts increased to 30% and the patient died of disease progression. The AML1/EVI1 gene has been shown to cause blast crisis in chronic myelogenous leukemia. This case suggested that the AML1/EVI1 gene may be involved in the progression of MDS together with del(7) (q22) and del(11) (q23).

Acute Disease↗
PubMed1998

Crystallization and preliminary X-ray diffraction studies of bleomycin-binding protein from bleomycin-producing Streptomyces verticillus.

A bleomycin-binding protein (BLMA) produced by bleomycin-producing Streptomyces verticullus was crystallized in a form suitable for X-ray diffraction analysis using the vapor-diffusion method. Crystals were grown at pH 5.7, in 0.2 M NH4 actate and 0.1 M Na acetate, using 30% PEG 4000 as a precipitant. They belong to the orthorhombic system, with space group P21212, cell dimensions a = 54. 90, b = 67.94, c = 35.60 A, and one BLMA molecule in the asymmetric unit. The crystals diffract X-rays well and the diffraction intensity data was collected up to 1.5 A resolution with a merging R value of 0.054 at beamline 6B of the Photon Factory. The diffraction data set is 94% complete.

Bacterial Proteins↗
PubMed1998

Successful treatment of a patient with cardiac lymphoma who presented with a complete atrioventricular block.

A patient with primary cardiac lymphoma, which is very rare, generally is regarded to have a poor prognosis. We herein report a patient with cardiac lymphoma who was treated successfully by systemic chemotherapy and radiotherapy using a pacemaker to control the complete atrioventricular (A-V) block. A 70-year-old man had a syncope caused by a complete A-V block. An echocardiogram, a computed tomographic scan, and magnetic resonance imaging of his chest showed a cardiac tumor. At this time, a biopsy of the cardiac tumor disclosed malignant lymphoma (diffuse large cell type, B cell type). The patient was thus treated with systemic chemotherapy and radiotherapy and, as a result, achieved a complete remission with a disappearance of the A-V block. Recently, several successful outcomes involving primary cardiac lymphoma have been reported because of the progress in diagnostic techniques including echocardiography, computed tomographic scanning, and magnetic resonance imaging, as well as improvement in the therapy of malignant lymphoma. Our clinical experience indicated that an early and accurate diagnosis combined with the appropriate therapy can thus help in obtaining a long survival in patients with primary cardiac lymphoma.

Aged↗
PubMed1997

Effect of long-term topical betaxolol on tissue circulation in the iris and optic nerve head.

The effect of long-term topical betaxolol on tissue circulation in the iris and optic nerve head was studied. Twenty microliters of 0.5% betaxolol ophthalmic solution was instilled in one eye of an albino rabbit and the same amount of physiological saline in the fellow eye twice daily for 20 days. A quantitative index of tissue blood velocity, NB value, was measured in the iris (21 rabbits) and optic nerve head (31 rabbits) of both eyes before the first instillation and 2 hr after completion of instillations, using a laser speckle tissue circulation analyser of which details have been reported previously. The intraocular pressure was also measured at 5-day intervals. The intraocular pressure was lowered by 2-3 mmHg only in the betaxolol-treated eye (P < 0.01). Both in the iris and optic nerve head no significant bilateral difference in the NB was seen before the first instillation, while it was significantly greater in the betaxolol-treated than in the contralateral control eye by about 10% after completion of instillations (P < 0.02-0.05). The difference between the NB after completion of instillations and that before the first instillation was significantly greater in the betaxolol-treated eye than in the contralateral control eye both in the iris and optic nerve head (P < 0.001-0.02). Twenty-day twice daily instillation of 0.5% betaxolol caused relatively small, but significant increase in tissue blood velocity in the ipsilateral iris and optic nerve head in albino rabbits, which may have clinical implications.

Administration, Topical↗
PubMed1997

Immunoglobulin class switch from IgA1 to IgG2 and simultaneous association with Bence Jones proteinuria in the escape phase in a myeloma patient treated with interferon alpha.

Immunoglobulin (Ig) class switch from alpha1 to gamma2 associated with kappa-type Bence Jones proteinuria was evident in the escape phase of an IgA1 myeloma patient treated with interferon alpha (IFN alpha). The additional M-protein, IgG2-kappa, level rapidly increased and was associated with Bence Jones proteinuria, whereas monoclonal IgA1-kappa progressively declined. The N-terminal 21 amino acid sequences of the kappa-chains of monoclonal IgA1, IgG2 and the Bence Jones protein were the same. The N-terminal 15 amino acid sequence of the gamma2-chain was identical to that of the alpha1-chain. Based on these findings, the IgA1 myeloma cells underwent a class switch in CH gene expression from alpha1 to gamma2 with cell differentiation in vivo. The mechanism of the Ig class switching is discussed from three points of view: (1) Increase in immature and plasmablastic myeloma cells in the escape phase is susceptible to Ig class switching by the T-cell-derived cytokines. (2) We presumed that administered IFN alpha increased the amounts of secreted IFN gamma from the Th1 cells. (3) Due to a large quantity of IFN gamma, an inducer of Cgamma2 germline transcript, Ig class switching occurred stepwise from the alpha1 constant region gene to the next 3'CH gamma2 gene.

Aged↗
PubMed1996

High occurrence of primary malignant neoplasms in patients with adult T-cell leukemia/lymphoma, their siblings, and their mothers.

BACKGROUND: Attempts were made to clarify the correlation between human T-cell leukemia/lymphoma virus (HTLV)-1 infection and malignant oncogenicity other than adult T-cell leukemia/lymphoma (ATL) in a case-control study. METHODS: The occurrence of primary malignant neoplasms (MN) in 110 ATL patients, their parents, and 430 siblings was compared with HTLV-1 seronegative non-Hodgkin's lymphoma (NHL) patients, their parents and 867 siblings. The chi-square test, odds ratio (OR), and 95% confidence intervals (CI) were used to determine the statistical significance of differences in the occurrence of the primary MN among ATL patients, HTLV-1 seronegative NHL patients, their siblings, and their parents. RESULTS: The occurrence of primary MN in the ATL patients was higher than the occurrence in HTLV-1 seronegative NHL patients (P = 0.0036; OR = 2.91; 95% CI: 1.42, 6.02). In siblings of the ATL patients, there was a higher occurrence of primary MN than in siblings of the HTLV-1 seronegative NHL patients (P < 0.0001; OR = 3.35; 95% CI: 2.01, 5.58). In mothers of the ATL patients, there was a higher occurrence of primary MN than in mothers of the HTLV-1 seronegative NHL patients (P = 0.0063; OR = 2.55; 95% CI: 1.30, 5.00), but not in fathers (P = 0.1602; OR = 1.68; 95% CI: 0.81, 3.47). CONCLUSIONS: There is an increased risk of primary MN in ATL patients, their siblings, and their mothers.

Aged↗
PubMed1996

C-myc expression affects proliferation but not terminal differentiation or survival of explanted erythroid progenitor cells.

The expression of c-myc was analyzed in murine and human erythroblasts throughout their differentiation in vitro into reticulocytes. The murine cells were splenic erythroblasts from animals infected with the anemia strain of Friend virus (FVA cells). In FVA cells cultured without EPO, the c-myc mRNA and protein levels decrease sharply within 3 to 4 h, showing that continual EPO stimulation is required to maintain c-myc expression. When cultured with EPO, the c-myc mRNA level of FVA cells is raised within 30 min of exposure. The c-myc mRNA and protein reach maxima at 1 to 3 h, then decline slowly to very low levels by 18 h. In contrast, c-fos and c-jun mRNA levels are not regulated by EPO in FVA cells. The human cells analyzed were colony-forming units-erythroid, CFU-E, derived in vitro by the culture of peripheral blood burst-forming units-erythroid (BFU-E). When grown in EPO and insulin-like growth factor 1 (IGF-1) these cells differentiate into reticulocytes over 6 days rather than the 2 days required for murine cells, but the c-myc mRNA kinetics and response to EPO parallel those of mouse cells at similar stages of differentiation. Both IGF-1 and c-kit ligand (SCF) cause an additive increase in c-myc mRNA in human CFU-E in conjunction with EPO. These additive effects suggest that EPO, IGF-1, and SCF affect c-myc mRNA accumulation by distinct mechanisms. Addition of an antisense oligonucleotide to c-myc in cultures of human CFU-E specifically inhibited cell proliferation but did not affect erythroid cell differentiation or apoptosis. When human cells were grown in high SCF concentrations, an environment which enhances proliferation and retards differentiation, antisense oligonucleotide to c-myc strongly inhibited proliferation, but such inhibition did not induce differentiation. This latter result indicates that differentiation requires signals other than depression of c-Myc and resultant depression of proliferation.

Animals↗
PubMed1996

[Comparison between monotherapy with imipenem/cilastatin sodium (IPM/CS) and combinations of IPM/CS and other drugs for treating bacterial infections in patients with hematopoietic disorders].

One hundred and nine patients with infections concurrent with hematopoietic disorders were treated with imipenem/cilastatin sodium (IPM/CS) either alone (IPM/CS monotherapy) or in combination with other antimicrobial drugs (IPM/CS combination therapy). The following results were obtained. 1. One hundred and nine patients were allocated at random to two groups: 53 patients to IPM/CS monotherapy and 56 patients to IPM/CS combination therapy. Fourteen patients (6 and 8 in the 2 groups, respectively) were excluded from the clinical evaluation. There were not significant differences between the two groups with respect to the background. 2. The efficacy rates of the 2 treatments against bacterial infections were as follows: in the IPM/CS monotherapy group, 62.5% in 8 patients with sepsis, 75.0% in 23 patients with fever of undetermined origin (FUO), 50.0% in 10 patients with pneumonia, and 68.3% in the 47 patients, and in the IPM/CS combination group, 85.7% in 7 patients with sepsis, 63.6% in 24 patients with FUO, 50.5% in 8 patients with pneumonia, and 67.4% in the 48 patients. The differences between the two groups were not significant. 3. Among the drugs used in combination with IPM/CS, antibiotics other than penicillins, cephalosporins, and aminoglycosides were used in 12 patients and a high efficacy rate of 91.7% was obtained. 4. Bacteriologically, 19 and 17 strains were isolated from the IPM/CS monotherapy and combination therapy groups respectively, and the eradication rates were 100% and 88.9% respectively. 5. Side effects were noted in 2 patients in the IPM/CS monotherapy group and 7 in the combination therapy group, but all of these resolved after discontinuation or completion of the treatment. The efficacies against severe bacterial infections in the presence of hematopoietic disorders were not different between IPM/CS alone and IPM/CS in combination with other antibiotics. Adverse reactions were uncommon with the monotherapy.

Adolescent↗
PubMed1995

Stem cell factor retards differentiation of normal human erythroid progenitor cells while stimulating proliferation.

Stem cell factor (SCF), the ligand for the c-kit tyrosine kinase receptor, markedly stimulates the accumulation of erythroid progenitor cells in vitro. We now report that SCF delays erythroid differentiation among the progeny of individual erythroid progenitors while greatly increasing the proliferation of these progeny. These effects appear to be independent of an effect on maintenance of cell viability. Highly purified day-6 erythroid colony-forming cells (ECFC), consisting mainly of colony-forming units-erythroid (CFU-E), were generated from human peripheral blood burst-forming units-erythroid (BFU-E). Addition of SCF to the ECFC in serum-free liquid culture, together with erythropoietin (EP) and insulin-like growth factor 1 (IGF-1), resulted in a marked increase in DNA synthesis, associated with a delayed peak in cellular benzidine positivity and a delayed incorporation of 59Fe into hemoglobin compared with cultures without SCF. In the presence of SCF, the number of ECFC was greatly expanded during this culture period, and total production of benzidine-positive cells plus hemoglobin synthesis were ultimately increased. To determine the effect of SCF on individual ECFC, single-cell cultures were performed in both semisolid and liquid media. These cultures demonstrated that SCF, in the presence of EP and IGF-1, acted on single cells and their descendants to delay erythroid differentiation while substantially stimulating cellular proliferation, without an enhancement of viability of the initial cells. This was also evident when the effect of SCF was determined using clones of ECFC derived from single BFU-E. Our experiments demonstrate that SCF acts on individual day-6 ECFC to retard erythroid differentiation while simultaneously providing enhanced proliferation by a process apparently independent of an effect on cell viability or programmed cell death.

Apoptosis↗
PubMed1995

Inhibition of heme synthesis induces apoptosis in human erythroid progenitor cells.

Heme synthesis by erythroid progenitor cells is maintained by erythropoietin (EP), insulin-like growth factor-I (IGF-I), and stem cell factor (SCF), and without these growth factors apoptosis (programmed cell death) occurs. To clarify the possible interaction between heme synthesis and programmed cell death of human erythroid progenitor cells, the effect of specific inhibition of heme synthesis on apoptosis of highly purified human erythroid colony forming cells (ECFC) was studied. When the amount of uncleaved DNA was determined as a measure of apoptosis, the heme synthesis inhibitors, succinylacetone (SA) (0.1 mmol/L) or isonicotinic acid hydrazide (INH) (10 mmol/L), significantly decreased the amount of uncleaved DNA (P < 0.01) in the presence of erythropoietin (EP). Addition of recombinant heavy-chain ferritin (rHF) (10 nmol/L), or deprivation of transferrin from the culture medium, which decreased heme synthesis, also reduced the amount of uncleaved DNA (P < 0.01). The production of apoptosis by diverse inhibitors of heme synthesis was in each case reversed by the addition of hemin (0.1 mmol/L) and did not occur with HL-60 cells. When the colony-forming capacity of ECFC was determined by plasma clot assay, SA, INH, or rHF reduced the number of CFU-E (P < 0.01), and the effect of SA was reversed by hemin. The addition of SA did not alter the c-myc response of ECFC to EP. These data indicate that inhibition of heme synthesis induces apoptosis of human erythroid progenitor cells, in a manner independent of an early c-myc response, and suggest that the presence of apoptosis in ineffective erythropoiesis may be secondary to impaired heme synthesis.

Apoptosis↗
PubMed1995

Adult T-cell leukemia with multiple lymphomatous polyposis of the gastrointestinal tract.

A rare case of adult T-cell leukemia (ATL) in which multiple lymphomatous polyposis (MLP) was revealed throughout the entire gastrointestinal tract is reported here. The polypectomy specimens taken from the rectum revealed infiltration of neoplastic T-cells, the integration of HTLV-1 proviral DNA, and increased CD4 (OKT4) and CD25 (IL-2R) cells. The analysis of surface markers of the lymphocytes from polypoid lesions may be useful for elucidating cell tropism and homing properties in the gastrointestinal tract. Although MLP has always been associated with B-cell lymphoma in the Western world, it is important for clinicians and pathologists to be aware that MLP may be caused by the infiltration of ATL cells.

Adult↗