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Biomedical subjects

K Muta

Publications and source records attributed to K Muta.

At least 19 recordsLinked to original sources
PubMed1992

Regulation of transferrin receptors by iron in human erythroblasts.

We investigated the regulatory mechanism of human erythroblast transferrin receptors (Tf.R) under conditions of iron deprivation and iron loading. Treatment of erythroblasts with an iron chelator, desferrioxamine, induced an increase in surface Tf.R number associated with an elevation of biosynthetic rate and the mRNA level of Tf.R. Reduced cellular iron pool increased the Tf.R number by altering the level of mRNA, as in nonhemoglobin-producing cells. Although treatment of erythroblasts with hemin induced a decrease in the biosynthetic rate and in the level of mRNA, the number of surface Tf.R did not decrease. This phenomenon may explain the fact that a high level of serum iron has no influence on the surface Tf.R number in vivo, as we reported previously. We suggest the existence of a regulatory mechanism specific for hemoglobin-producing cells that keeps surface Tf.R expression constant despite iron loading.

Blotting, Northern↗
PubMed1992

Anemia and neutropenia in a case of copper deficiency: role of copper in normal hematopoiesis.

We present a patient who developed severe anemia and neutropenia after receiving parenteral nutrition for 2.5 years. The serum levels of copper and ceruloplasmin were low, and the bone marrow showed the presence of ringed sideroblasts and vacuolated immature cells. The administration of copper chloride by bolus injection led to a rapid improvement in anemia and neutropenia. The number of progenitor cells (colony-forming unit-granulocyte-macrophage and erythrocyte) present before the copper supplementation was well preserved. It is therefore suggested that copper enzymes play an important role in the maturation of hematopoietic cells.

Aged↗
PubMed1992

[CD7 (+) stem cell leukemia presenting different phenotypes in lymph node and bone marrow].

A 27-year-old male with systemic lymphadenopathy was diagnosed as lymphoblastic-type lymphoma by inguinal lymph node biopsy in September, 1990. Bone marrow at the initial diagnosis contained 55.4% lymphoblasts with a phenotype of peroxidase (-), CD7 (+), CD4 (-), CD8 (-). Lymphadenopathy and lymphoblasts in bone marrow disappeared after MACOP-B therapy. In December, 1990, however, the patient again noticed swelling of cervical lymph nodes. At this time, the bone marrow contained 36.4% myeloblasts with a peroxidase (+), CD7 (+), CD13 (+), CD33 (+) phenotype. Cytogenetic and genetic study revealed that the lymphoblasts at the initial diagnosis and the myeloblasts at relapse shared an common abnormal karyotype, 11p-, and the same rearranged band of T-cell receptor delta, gamma, beta genes, suggesting that these two blasts originated from the same clone. The blasts obtained from the cervical lymph node at relapse were still negative for peroxidase, in contrast to the blasts from bone marrow. These findings suggest that this leukemia originated from a stem cell and differentiated along multilineage pathways.

Adult↗
PubMed1992

[Two cases of acute promyelocytic leukemia in pregnancy and the effect of anthracyclines on fetal development].

Two patients with acute promyelocytic leukemia (APL) in 2nd and 3rd trimester of pregnancy are reported on. Case 1: 38-year-old female consulted our hospital because of bleeding tendency and pancytopenia in April, 1988. She was diagnosed as having APL with disseminated intravascular coagulopathy (DIC) and was found to be in the 14th week of gestation. Combined chemotherapy (BHAC-DMP) including the total dose (440 mg) of daunorubicin (DNR) resulted in intrauterine fetal death at 19 weeks of gestation. The fetus was severely anemic and the bone marrow was hypoplastic. Case 2: A 27-year-old female was diagnosed as having APL with DIC at 29 weeks of gestation. BHAC-DMP including 440 mg DNR achieved complete remission. At 35 weeks of gestation, she delivered a normal infant by Caesarean section. The child had normal hematological findings and showed normal growth. Both cases developed APL accompanied by DIC during pregnancy and were treated with a similar regimen including high dose of anthracyclines. Case 2 treated in the late period of gestation delivered a normal infant, while fetal death resulted in case 1, treated in the early period of gestation. We reviewed the literature regarding chemotherapy using anthracyclines during pregnancy.

Adult↗
PubMed1991

Polyneuropathy in acute megakaryoblastic leukemia.

Peripheral neuropathy is a rare complication in leukemia. The authors report a patient with acute megakaryoblastic leukemia (AMKL) and progressive symmetric polyneuropathy. Intense infiltration of leukemic cells in a peripheral nerve was observed at autopsy. This is the first report of AMKL with peripheral nerve involvement to the knowledge of the authors.

Extremities↗
PubMed1991

Absence of correlation between cytotoxicity and drug transport by P-glycoprotein in clinical leukemic cells.

Development of resistance to cytotoxic agents is a common problem in the treatment of acute leukemia. In cell lines having multidrug resistance (MDR) phenotype, a decrease in the intracellular accumulation of drugs has been closely related to the overexpression of P-glycoprotein/mdr1 genes. We analyzed the relationship between the cytotoxicity of adriamycin (ADR) in vitro, intracellular accumulation of ADR, and the expression of P-glycoprotein on fresh leukemic cells from 19 patients at their initial presentation and from 9 relapsed patients. Pretreatment patients showed significantly higher ratio of complete remission than relapsed patients, and mean value of IC50 for adriamycin in initial presentation was higher than at relapse. But we found no significant relationship between in vitro cytotoxicity and drug transport. In addition, only 2 of the 5 relapsed patients examined by monoclonal antibody C219 expressed the P-glycoprotein. These results suggest that the acquisition of clinical drug resistance may involve various mechanisms other than the reduction of drug accumulation with P-glycoprotein expression.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1991

[A high serum level of interleukin-6 in a patient with aggressive multiple myeloma].

A 58-year-old female was admitted to our hospital because of anemia in March 1987. Monoclonal protein (IgA, kappa) was detected and a diagnosis of multiple myeloma was made. Partial remission was obtained after VAD therapy with alpha-interferon. In December 1989, she was readmitted because of a pathological fracture of the left humerus. A white blood cell count was 4400/microliters with 30% myeloma cells and the urine protein (Bence Jones protein) was 26 g/day. Systemic chemotherapy was not effective. She developed pleural and pericardial effusions, bone mass, disturbance of consciousness and died of respiratory failure only 3 months after readmission. The pleural and pericardial fluids contained many myeloma cells. c-myc gene rearrangement was detected in myeloma cells obtained from the pleural fluid using c-myc exon1 and exon2 probes. The levels of interleukin-6 (IL-6) measured by ELISA was 107.4 pg/ml in serum, 56.2 pg/ml in pleural fluid and 780.0 pg/ml in pericardial fluid. Because of the lack of any overt infectious focus, the level of IL-6 appears to have been related to aggressive proliferation of myeloma cells. It was of interest that C-reactive protein, induced by IL-6, was a good marker reflecting disease activity.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1990

The transferrin receptor system is not involved in the pathogenesis of hematological disorders with 3q inversion.

To clarify the idea that an alteration of the transferrin receptor (TF-R) gene, localized to 3q26, may be of pathogenetic significance in hematological disorders with 3q anomaly, we studied the TF-R systems of erythroblasts from both functional and genetic aspects. The patient described here had refractory anemia with an excess of blasts (RAEB), with paracentric inversion, inv(3)(q21q26). The patient had the characteristic findings of micromegakaryocytosis and thrombocytosis, with giant platelets. There was no functional abnormality of TF-R as far as number of binding sites, affinity, molecular weight, or recycling kinetics were concerned. Furthermore, we could not recognize any rearrangement of the TF-R gene with Southern blot analysis. These data suggest that TF-R is not involved in the pathogenesis of leukemogenesis and thrombocytosis of the disease.

Chromosome Inversion↗
PubMed1990

Mechanisms involved in the development of adriamycin resistance in human leukemic cells.

We have developed three adriamycin (ADR)-resistant K562 sublines with different degrees of resistance. These sublines show a decreased accumulation and an increased efflux of ADR in proportion to the degree of resistance. Two membrane proteins (mol. wt 170,000 and 230,000) reactive with monoclonal antibody against P-glycoprotein were highly expressed in both the K562/ADR200 and the K562/ADR500 subline. Less resistant K562/ADR80 cells contained only small amounts of mol. wt 230,000 protein. Thus, the level of P-glycoprotein expression was not proportionate to the degree of ADR efflux. Verapamil treatment could not completely reverse ADR resistance. No significant change of glutathione-s-transferase activity nor in the level of DNA topoisomerase II was detected in resistant sublines. In our sublines it seems that P-glycoprotein is one of the mechanisms for resistance, but additional mechanisms may be involved.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1990

Percutaneous penetration of acyclovir through excised hairless mouse and rat skin: effect of vehicle and percutaneous penetration enhancer.

The effects of vehicle and percutaneous penetration enhancer on the penetration of acyclovir through excised hairless mouse and rat skin were investigated. Four solvents, propylene glycol (PG), ethanol (ET), isopropanol (IPA), and isopropyl myristate (IPM), were employed as vehicles, in combination with four enhancers, 1-farnesylazacycloheptan-2-one (7FU), 1-geranylazacycloheptan-2-one (7GU), 1-geranylazacyclopentan-2-one (5GU), and 1-dodecylazacycloheptan-2-one (Azone). Acyclovir was suspended in vehicles to avoid the effect of the thermodynamic activity of acyclovir in the vehicle. The penetration of acyclovir through hairless mouse skin from IPA was enhanced by 7GU, whereas that from IPM was not affected. All combinations of vehicle and penetration enhancer were examined using rat skin. No effect of the enhancers was observed in the IPM vehicle. The estimated solubility parameters of vehicles and enhancers indicated that the polarities of IPM and the enhancers are similar, which prevents effective penetration of the enhancers from IPM. However, the penetration of acyclovir from the other vehicles was increased by the enhancers. The combination of hydrophilic vehicle and hydrophobic enhancer resulted in a large enhancing effect. The disappearance of the enhancers from the vehicle correlated with their enhancing activity, but other factors also seemed to affect the penetration enhancement of acyclovir.

Acyclovir↗
PubMed1990

Abnormality of platelet membrane glycoprotein GPIIb in a myelodysplastic syndrome with 3q inversion presenting with marked dysmegakaryopoiesis.

Platelet membrane glycoproteins were analyzed in a case of myelodysplastic syndrome with inv(3) (q21q26) presenting with prominent dysmegakaryopoiesis by three different labelling techniques for surface proteins. Markedly decreased level of platelet membrane glycoprotein GPIIb was observed in the patient's platelets by terminal sialic acid labelling method, whereas no significant changes in the levels of glycoproteins including GPIIb could be detected either by penultimate galactose labelling or by tyrosine/histidine labelling. These results indicate a decreased sialylation of GPIIb in the patient's platelets, implying aberrant process in thrombopoiesis in the disease.

Bone Marrow Examination↗
PubMed1988

Regulation of biosynthesis and phosphorylation of P210bcr/abl protein during differentiation induction of K 562 cells.

The changes of P210bcr/abl and other tyrosine phosphorylated proteins in K562 cells during growth and differentiation were studied by metabolic labeling with 32PO4 and immunoprecipitation with anti-phosphotyrosine sera. The anti-phosphotyrosine sera recognized P210bcr/abl and other phosphoproteins with mol wt of 150, 115, 100, 70 and 64 kD. The 2-day incubation of K562 cells with inducers for differentiation, hemin, sodium butyrate and TPA, decreased the level of P210bcr/abl protein and other phosphoproteins. Inhibitors of tyrosine protein kinase, amiloride and genistein, also reduced the phosphorylation of P210bcr/abl protein and other substrates, but did not induce differentiation of the cells. Although most of these additives inhibited the cell growth, cytotoxic agents such as adriamycin, vincristine and Ara-C did not affect the level of P210bcr/abl protein. The experiments using 35S-methionine labeled cells and the immunoprecipitation with anti-abl sera suggested that reduced biosynthesis but not dephosphorylation of P210bcr/abl protein mainly accounted for the reduction of P210bcr/abl protein reacting to anti-phosphotyrosine sera in differentiation-induced cells. These results indicate that the reduction of P210bcr/abl protein synthesis plays some roles in cellular differentiation of K562 cells.

Cell Differentiation↗
PubMed1988

Possible mechanism of ineffective erythropoiesis by an altered transferrin receptor cycle in erythroleukemia.

Involvement of the transferrin receptor cycle was noted in erythroblasts from a patient with erythroleukemia (FAB classification M6). The kinetics of transferrin receptor cycle in bone marrow erythroblasts was obtained by pulse-chase experiments before the initiation of therapy. Internalization of transferrin was impaired and resulted in a delayed peak of internalized transferrin, as compared with the kinetics pattern seen in healthy subjects. The subsequent exocytosis of the internalized ligand was also delayed. Thus, transferrin receptor cycle seems to be influenced all along the transferrin pathway, hence transferrin travels more slowly in erythroblasts in erythroleukemia. The altered transferrin receptor cycle led to a diminished iron uptake per surface transferrin receptor (approximately 30% of that in healthy subjects), and the incorporation of iron into heme was greatly reduced. Our observations suggest a possible role for the altered transferrin receptor cycle in the pathogenesis of defective heme synthesis and ineffective erythropoiesis in erythroleukemia.

Endocytosis↗