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Biomedical subjects

T Inaba

Publications and source records attributed to T Inaba.

At least 253 records · Page 14Linked to original sources
PubMed1993

Carbonyl (phenone) reductase in human liver: inter-individual variability.

The enzyme family carbonyl reductase, which catalyses the reduction of xenobiotic as well as endogenous ketones and aldehydes, has not been very well studied in terms of its biological functions and structural aspects. The aim of the present study was to check for the occurrence of inter-individual variability of carbonyl reductase activity in human liver. In vitro metabolism of p-nitroacetophenone (PNAP, a prototype substrate) indicated the presence of a high- and low-affinity enzyme site. The reductase activity of 17 kidney donor livers was screened at two concentrations (0.05 and 0.5 mM PNAP, below and above Km). The rates of reductase activity at 0.05 mM suggested a normal distribution. In contrast, at 0.5 mM the rates indicated a non-normal distribution, i.e. bi- or tri-modality. As an index of variability of enzyme affinity, ratios of velocities at 0.5 to 0.05 mM PNAP were calculated in order to check their frequency distributions. Three out of 17 kidney donor livers showed an atypical ratio. In these three cases, the high ratio was due to the low activity of the high affinity form of carbonyl reductase. Autopsy livers are a more readily available tissue source and about half the activity of the kidney donor livers was found in 43 autopsy livers indicating that they are a useful source of human tissue for studies of carbonyl reductase.

Acetophenones↗
PubMed1993

Inhibition of human cytochrome P450 2D6 (CYP2D6) by methadone.

1. In microsomes prepared from three human livers, methadone competitively inhibited the O-demethylation of dextromethorphan, a marker substrate for CYP2D6. The apparent Ki value of methadone ranged from 2.5 to 5 microM. 2. Two hundred and fifty-two (252) white Caucasians, including 210 unrelated healthy volunteers and 42 opiate abusers undergoing treatment with methadone were phenotyped using dextromethorphan as the marker drug. Although the frequency of poor metabolizers was similar in both groups, the extensive metabolizers among the opiate abusers tended to have higher O-demethylation metabolic ratios and to excrete less of the dose as dextromethorphan metabolites than control extensive metabolizer subjects. These data suggest inhibition of CYP2D6 by methadone in vivo as well. 3. Because methadone is widely used in the treatment of opiate abuse, inhibition of CYP2D6 activity in these patients might contribute to exaggerated response or unexpected toxicity from drugs that are substrates of this enzyme.

Adolescent↗
PubMed1993

Trilineage response in severe aplastic anemia following long-term therapy with recombinant human granulocyte colony-stimulating factor.

We investigated the effects of long-term therapy with recombinant human granulocyte colony-stimulating factor (rhG-CSF) in a 69-year-old man with severe aplastic anemia (SAA). The patient was too old to receive a bone marrow transplantation, and high-dose methylprednisolone and antilymphocyte globulin were ineffective. We administered rhG-CSF in combination with metenolone acetate. Trilineage blood cell components were recovered 6 months later. These findings suggest that long-term G-CSF therapy may be beneficial in patients with SAA who are not candidates for bone marrow transplantation.

Aged↗
PubMed1993

Recombinant human granulocyte colony-stimulating factor in combination with continuous infusion of cytosine arabinoside for the treatment of refractory acute myelogenous leukemia.

Because recombinant human granulocyte colony-stimulating factor (G-CSF) has been reported to increase the sensitivity of acute myelogenous leukemia (AML) blast cells to cytosine arabinoside (Ara-C) in vitro, we treated a patient with refractory AML with an Ara-C-based regimen in combination with G-CSF (G-CSF/Ara-C therapy). G-CSF (50 micrograms/m2/day, subcutaneous injection) was administered simultaneously with a continuous intravenous infusion of Ara-C (70 mg/m2/day). Complete remission was achieved, however, severe neutropenia, documented infection, stomatitis, and diarrhea were observed. In vitro studies using 3H-thymidine uptake and dual parameter flow-cytometric analysis of DNA and proliferating cell nuclear antigen showed that leukemic blast cells in S phase were increased after incubation with G-CSF. G-CSF also enhanced expression of the transferrin receptor (CD71) on blast cells in vitro. These observations suggest that G-CSF/Ara-C therapy may be useful in the treatment of high-risk AML.

Bone Marrow↗
PubMed1993

Macrophage colony-stimulating factor regulates both activities of neutral and acidic cholesteryl ester hydrolases in human monocyte-derived macrophages.

Macrophage colony-stimulating factor (M-CSF) regulates cholesterol metabolism in vivo and in vitro. We studied the effects of M-CSF on enzyme activities of acidic cholesteryl ester (CE) hydrolase, neutral CE hydrolase, and acyl-coenzyme A:cholesterol acyltransferase (ACAT), all of which are involved in cellular cholesterol metabolism in macrophages. During the differentiation of monocytes to macrophages, these enzyme activities were induced and further enhanced in response to M-CSF. M-CSF (100 ng/ml) enhanced acidic and neutral CE hydrolase and ACAT activities by 3.2-, 4-, and 2.3-fold, respectively, in the presence of acetyl LDL. The presence of acetyl LDL influenced these enzyme activities. ACAT and acidic CE hydrolase activities were increased and neutral CE hydrolase activity was decreased, indicating that these enzymes are regulated by intracellular cholesterol enrichment. M-CSF increased the ratios of acidic CE hydrolase to ACAT activity and of neutral CE hydrolase to ACAT activity. The results suggest that M-CSF enhances net hydrolysis of CE by stimulating the two CE hydrolases to a greater extent than ACAT, and M-CSF may reduce the rate of atherogenesis.

Base Sequence↗
PubMed1993

[Acute basophilic leukemia: a case report].

A 56-year-old woman was admitted to our hospital in January, 1990 because of fever and petechiae. Leukocyte count of peripheral blood showed 41,000/microliters with 89% immature cells, and bone marrow was normocellular with 96.2% immature cells. They were medium to large in size, positive for peroxidase staining, CD-13 and CD-33. Half of them contained azurophilic granules. They showed metachromasia by toluidine blue, contained basophilic granules in electron microscopic examination and reacted to G-CSF, G-CSF and IL-3. She was diagnosed as acute basophilic leukemia and treated with BHAC-DMP and B triple-V regimen, but remission was not attained. She died of peritonitis due to gastrointestinal tract perforation and pneumonia in March, 1990. This is the fifteenth case of acute basophilic leukemia reported in Japan, and the hematological examinations performed in this patient were demonstrated.

Bone Marrow↗
PubMed1993

Autoimmune thrombocytopenia following peripheral blood stem cell autografting.

A 22-year-old woman diagnosed as AML (M3) received myeloablative chemotherapy followed by autologous peripheral stem cell transplantation (PBSCT). Rapid hematopoietic reconstitution occurred. By day 10, the neutrophil count was > 0.5 x 10(9)/l and the platelet count > 50 x 10(9)/l. The platelet count was 145 x 10(9)/l on day 20. Purpura developed on the anterior chest and legs on day 50, at which time the platelet count fell to 17 x 10(9)/l. The BM was hypocellular with an increase in megakaryocytes. Platelet-associated IgG (PAIgG) was 88.1 ng/10(7) platelets (normal range 9-25 ng/10(7)); a diagnosis of idiopathic thrombocytopenic purpura (ITP) was made. Prednisolone administration led to an increase in the platelet count and a decrease in PAIgG. Analysis of lymphocyte subsets revealed an increased number of CD3+ gamma/delta T cells. It is postulated that the thrombocytopenia in this case was due to an autoimmune mechanism such as ITP.

Adult↗
PubMed1993

Human hepatic cytochrome P450 2D6-like activity in nonhuman primates: catalytic characterization in vitro.

Previous studies have identified the monkey as an animal model for the genetic polymorphism affecting human hepatic cytochrome P450 2D6 enzyme. However, contrary to an earlier in vivo observation, the present study failed to find evidence of polymorphism of this enzyme activity in liver preparations of 84 African green (Cercopithecus aethiops) monkeys. The kinetics of dextromethorphan O-demethylation were similar in liver microsomes from African green (n = 21) and Crab eater (Macaca fascicularis, n = 7) monkeys (Km = 1.1 +/- 0.07 and 1.7 +/- 0.27 microM; Vmax = 215 +/- 71.7 and 152 +/- 21.1 nmol/mg/h, respectively). These Km values were lower and less variable than those in liver microsomes from 10 human extensive metabolizers (5.3 +/- 2.43 microM). Furthermore, the Vmax of the reaction in human liver microsomes was significantly lower (32 +/- 15.7 nmol/mg/h; P < .001). Inhibitor constants (Ki values) determined in monkey and human liver microsomes were highly correlated (r = 0.97), but two high-affinity inhibitors of the human enzyme (quinidine and lobeline) were approximately 40-fold less potent in monkey livers than in human livers. These data show that the monkey enzyme is functionally homologous, but is not identical to human hepatic cytochrome P450 2D6. Failure to observe poor metabolizer monkeys does not preclude their potential usefulness in evaluating the role of human hepatic cytochrome P450 2D6 activity in drug addiction and neurotoxicity because of the possibility of producing poor metabolizer phenocopies by potent hepatic cytochrome P450 2D6-like enzyme inhibitors in monkeys.

Animals↗
PubMed1993

[Chronic myelomonocytic leukemia and esophageal cancer developed in a renal allograft recipient].

A 46-year-old man treated with azathioprine (100-150 mg/day) and prednisolone (10mg/day) for 14 years after allogeneic renal transplantation, was admitted to our hospital in December, 1988 for the evaluation of leukocytosis. His leukocyte count was 32,700/microliters with 38% monocytes and 2% blasts. Chromosomal analysis of the bone marrow revealed 45, XY, -7. He was diagnosed as chronic myelomonocytic leukemia (CMML), and treated with low-dose Ara-C. Two months later, he progressed to overt acute leukemia, and he complained of difficulty in swallowing. Endoscopic examination revealed esophageal cancer. The patient died of respiratory failure on April 18, 1989. This case suggests that immunosuppressive agents might play an important role on the pathogenesis of CMML and esophageal cancer.

Azathioprine↗
PubMed1992

Platelet-derived growth factor BB-dimer suppresses the expression of macrophage colony-stimulating factor in human vascular smooth muscle cells.

Vascular smooth muscle cell is a major cell component involved in the process of atherosclerosis. In the present study, we investigated the effects of platelet-derived growth factor (PDGF)-BB dimer on the expression of macrophage-colony stimulating factor (M-CSF) in vascular smooth muscle cells isolated from human umbilical artery. On Northern blot analysis of total RNAs isolated from smooth muscle cells, with human cDNA for M-CSF, a marked dose-dependent reduction of mRNA level was found in PDGF-BB-treated smooth muscle cells. Cellular production of M-CSF was estimated by immunoblot analysis of cell lysate with specific polyclonal antibody against recombinant human M-CSF. A concentration of 10 ng/ml PDGF-BB significantly reduced M-CSF mass in smooth muscle cells compared with that in the absence of PDGF-BB. These results suggest that PDGF-BB plays an important role in the cellular metabolism of vascular wall by regulating the rate of M-CSF production in vascular smooth muscle cells.

Antibodies↗
PubMed1992

Fusion of the leucine zipper gene HLF to the E2A gene in human acute B-lineage leukemia.

A t(17;19) chromosomal translocation in early B-lineage acute leukemia was shown to result in chimeric transcripts that contain sequences from the E2A basic helix-loop-helix transcription factor gene on chromosome 19, fused to sequences from a previously unidentified gene (HLF) on chromosome 17 that encodes a hepatic leukemia factor. The chimeric protein consisted of the amino-terminal transactivation domain of E2A linked to the carboxyl-terminal basic region-leucine zipper domain of HLF. HLF was normally expressed in liver and kidney, but not in lymphoid cells, and was found to be closely related to the leucine zipper-containing transcription factors DBP (albumin D-box binding protein) and TEF (thyrotroph embryonic factor), which regulate developmental stage-specific gene expression.

Adenovirus Early Proteins↗
PubMed1992

Platelet-derived growth factor induces c-fms and scavenger receptor genes in vascular smooth muscle cells.

Vascular smooth muscle cells proliferate and transform to foam cells in the process of atherosclerosis. In the present study, we demonstrated that platelet-derived growth factor (PDGF)-BB induced expression of proto-oncogene c-fms in vascular smooth muscle cells, which normally do not express c-fms, isolated from either human umbilical artery or rabbit aorta. No effect of the protein kinase C activator, phorbol ester, was demonstrated on mRNA expression of c-fms. In contrast, the scavenger receptor activity was induced by both PDGF-BB and phorbol ester. These results indicate that two characteristic genes of monocyte-macrophages were induced by PDGF-BB via the different pathways, and suggest that PDGF-BB plays an important role in initiating phenotypic conversion of smooth muscle cells to macrophage-like cells.

Animals↗
PubMed1992

Differential expression of myogenic regulatory genes, MyoD1 and myogenin, in human rhabdomyosarcoma sublines.

A cell line (SCMC-MM-1) was established from a human abdominal tumor that was initially diagnosed as a malignant mesenchymoma by histological, immunohistochemical and clinical criteria. The cell line was composed of 2 morphologically and immunohistochemically distinct cell types, one with a small polygonal phenotype (P-type), characterized by the immunostaining of vimentin and the presence of a few electron-microscopically visible organelles, and the other with a giant tubular phenotype (T-type), characterized by the immunostaining of desmin, alpha-sarcomeric actin and skeletal-muscle myosin, and the presence of thick and thin myofilaments and Z-line materials. The parental cell line was cloned into 2 sublines, a P-type clone (SCMC-MM-1-19P) and a T-type clone (SCMC-MM-1-1T), which shared both 2q37 and 11p15 translocations, the characteristic chromosomal aberrations for rhabdomyosarcoma, with the parental SCMC-MM-1 cell line. Northern-blot analyses of the myogenic regulatory genes, including MyoD1 and myogenin, demonstrated the expression of MyoD1 in both of these sublines. Myogenin was very weakly expressed in the SCMC-MM-1-19P subline, but strongly expressed in the SCMC-MM-1-1T subline. Chromosomal and myogenic-regulatory-gene analyses revealed that both of these sublines were rhabdomyosarcoma cell lines. Furthermore, the regulatory-gene analyses indicated that these 2 sublines represented 2 distinct differentiation stages of myoblasts, and that MyoD1 and myogenin could serve as the lineage marker and the differentiation marker, respectively, of human rhabdomyosarcoma.

Blotting, Northern↗
PubMed1992

Different molecular consequences of the 1;19 chromosomal translocation in childhood B-cell precursor acute lymphoblastic leukemia.

The prognostically important 1;19 chromosomal translocation can alter the E2A gene on chromosome 19p13 in childhood B-cell precursor acute lymphoblastic leukemia (ALL), leading to formation of a fusion gene (E2A-PBX1) that encodes a hybrid transcription factor with oncogenic potential. It is not known whether this molecular alteration is a uniform consequence of the t(1;19) or is restricted to translocation events within specific immunologic subtypes of the disease. Therefore, we studied leukemic cells from 25 cases of B-cell precursor ALL, with or without evidence of cytoplasmic Ig mu heavy chains (cIg); 17 cases had the t(1;19) by cytogenetic analysis. Leukemic cell DNA samples were analyzed by Southern blotting to detect alterations within the E2A genomic locus; a polymerase chain reaction assay was used to identify expression of chimeric E2A-pbx1 transcripts in leukemic cell RNA; and immunoblotting with anti-Pbx1 antibodies was used to detect hybrid E2A-Pbx1 proteins. Of 11 cases of cIg+ ALL with the t(1;19), 10 had E2A-pbx1 chimeric transcripts with identical junctions and a characteristic set of E2A-Pbx1 hybrid proteins. Each of these cases had E2A gene rearrangements, including the one in which fusion transcripts were not detected. By contrast, none of the six cases of t(1;19)-positive, cIg- ALL had evidence of rearranged E2A genomic restriction fragments, detectable E2A-pbx1 chimeric transcripts, or hybrid E2A-Pbx1 proteins. Typical chimeric E2A-pbx1 transcripts and proteins were detected in one of eight cIg+ leukemias in which the t(1;19) was not identified by cytogenetic analysis, emphasizing the increased sensitivity of molecular analysis for detection of this abnormality. We conclude that the molecular breakpoints in cases of cIg- B-cell precursor ALL with the t(1;19) differ from those in cIg+ cases with this translocation. Leukemias that express hybrid oncoproteins such as E2A-Pbx1 or Bcr-Abl have had a poor prognosis in most studies. Thus, molecular techniques to detect fusion genes and their aberrant products should allow more timely and appropriate treatment of these aggressive subtypes of the disease.

Adolescent↗
PubMed1992

Expression of M-CSF receptor encoded by c-fms on smooth muscle cells derived from arteriosclerotic lesion.

Vascular smooth muscle cells in atherosclerotic lesions are phenotypically different from those in the normal arterial wall, and no expression of macrophage colony stimulating factor (M-CSF) receptor encoded by the proto-oncogene c-fms has been demonstrated in normal smooth muscle cells. In the present study, we demonstrated expression of c-fms and high affinity binding of M-CSF in smooth muscle cells isolated from an experimental rabbit model of arteriosclerosis (intimal smooth muscle cells), while no expression of c-fms was shown in medial smooth muscle cells. In the immunocytochemical analysis, both types of smooth muscle cells similarly reacted with an antibody specific to muscle cells (HHF 35) but did not react with an antibody specific to rabbit macrophages (RAM 11). In intimal smooth muscle cells, when cells were incubated with acetylated low density lipoproteins (LDL), the binding of acetylated LDL and foam cell formation were observed. In response to M-CSF, tyrosine-phosphorylation, as analyzed by the detection of anti-phosphotyrosine-reactive proteins, and an increased rate of cell proliferation were observed in intimal smooth muscle cells. These results indicated that intimal smooth muscle cells have the characteristics of monocyte-macrophages such as the expression of c-fms, which may be related to their proliferation and phenotypic conversion into foam cells in atheromatous lesions.

Animals↗
PubMed1992

Immunophenotype and DNA content of myeloma cells in primary plasma cell leukemia.

To clarify the biological characteristics of the myeloma cells in primary plasma cell leukemia (PCL), we studied the immunological phenotype and DNA content of cells from five patients with primary PCL as compared to those from the patients with typical multiple myeloma (MM). In two of five patients with PCL myeloma cells had B-cell-associated antigens (B1, J5) and surface immunoglobulin in addition to plasma cell associated antigens, suggesting that these cells are immunologically immature as compared to mature plasma cells. Concerning the DNA content of myeloma cells, two of four patients had hypodiploid while two had diploid myeloma cells. In contrast, 24 of the 37 (65%) patients with typical MM had hyperdiploid and 1 had hypodiploid myeloma cells. These observations suggest that the myeloma cells in PCL are immunologically heterogeneous. The increased incidence of hypodiploidy in PCL may explain its relatively poor prognosis as previously shown in those with typical MM and hypodiploid DNA content.

Adult↗
PubMed1992

Macrophage colony stimulating factor prevents the progression of atherosclerosis in Watanabe heritable hyperlipidemic rabbits.

The early atherosclerotic lesion is characterized by the presence of macrophage-derived foam cells. Macrophage colony stimulating factor (M-CSF) specifically stimulates the functions of the monocyte-macrophages. To elucidate the effects of M-CSF in the atherogenic process in vivo, we administered human recombinant M-CSF into Watanabe heritable hyperlipidemic (WHHL) rabbits, an animal model for familial hypercholesterolemia. Three hundred micrograms of M-CSF were intravenously injected into WHHL rabbits aged 2.5 months, three times a week for 8.5 months. After the M-CSF treatment, we found very retarded progression of atherosclerosis. The accumulation of cholesterol ester was remarkably decreased in the aortae of M-CSF-treated animals (0.60 +/- 0.32 mg/g tissue), as compared to those of controls (4.32 +/- 0.61 mg/g tissue). Furthermore, the percentage of the surface area of the aorta with macroscopic plaque in animals treated with M-CSF was 14.3 +/- 6.2%, much less than that in controls receiving saline injection (38.8 +/- 8.0%). Thus, M-CSF definitely prevented the progression of atherosclerosis in WHHL rabbits by influencing macrophage functions.

Animals↗