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Biomedical subjects

M Tagawa

Publications and source records attributed to M Tagawa.

At least 217 records · Page 12Linked to original sources
PubMed1989

[Marked dysmyelopoiesis after induction chemotherapy in a case of acute myelomonocytic leukemia (M 4) with t(6; 11)].

A case of AML (M 4) with t(6; 11) showed recovery to myelodysplastic syndrome (MDS)-like bone marrow after one course of DCMP regimen. Dysplastic changes of three cell-lineages were observed and micromegakaryocytes were markedly increased in number. Recovering hematopoiesis was incomplete. During MDS-like phase, t(6; 11) disappeared, reverting to normal karyotypes. Low dose ara-C regimen did not show any effect. AML soon relapsed with reappearance of t(6; 11). MDS-like abnormal hematopoiesis has recently been reported to occur after remission induction therapy or at the time of relapse. G-6PD isozyme study revealed in a remission case of AML that hematopoiesis still consisted of abnormal clone in spite of karyotypic normalization. The abnormal hematopoiesis observed in our case can be referred to such a clonal disorder predominating after disappearance of blastic component of AML. It seems important to reveal what proportion of de novo AMLs shows such an abnormal hematopoiesis and to establish suitable therapeutic approach.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1989

[Effects of low dose Ara-C regimen in acute leukemias and RAEB].

Recent increase of leukemia among elderly patients prompted us to investigate the types of leukemia which can be induced into remission by low-dose Ara-C (LDAC) regimen. LDAC regimen was performed in 30 cases with overt acute leukemia (A), hypoplastic leukemia (B), and RAEB (C); Group A consists of M1 (1 case), M2 (4 cases), M3 (1 case), M4 (4 cases), M6 (1 case), and ALL (2 cases), Group B AML (8 cases), ALL (2 cases), and null (1 case), Group C RAEB (2 cases), and RAEB-T (4 cases). Complete remission (CR) rate was 23% (3/13) in group A, 64% (7/11) in group B, 0% (0/6) in group C. Partial remission rate was 33% (2/6) in group C. In group A, patients with M2 were induced into CR. In group B, both AML and ALL were induced into CR. Hypocellular marrow indicating low leukemic burden related to good sensitivity to Ara-C. Duration of CR was rather short; mean duration being 5.3 months. In group C, 2 PR cases of RAEB showed partial hematological recovery. LDAC regimen is effective especially for most of hypoplastic leukemia and some of M2. Side effects were tolerable, but all CR cases passed through bone marrow hypoplasia and needed supportive cares.

Acute Disease↗
PubMed1988

Thyroxine surge in metamorphosing flounder larvae.

The tissue concentration of thyroxine (T4) in larval flounder (Paralichthys olivaceus) was studied at various stages of their metamorphosis using a specific radioimmunoassay developed for samples obtained by quantitative extraction of the hormone from fish eggs and larvae. T4 concentrations were below the limit of detection in extracts of fertilized eggs and larvae until the end of prometamorphosis. Several dorsal fin rays continued growing from premetamorphosis until the end of prometamorphosis. The hormone became detectable at the onset of metamorphic climax when the elongated dorsal fin rays stopped growing. A sharp increase in tissue T4 concentration was observed in midclimax of metamorphosis, and the high level of T4 (11-13 ng/g body weight) was maintained until the end of the climax. The period of elevated T4 levels coincided with resorption of the elongated dorsal fin rays. The right eye completed translocation from the right to the left side of the body during metamorphic climax. The tissue T4 level declined to about a half of the peak value during postclimax, and then increased moderately in later adult-type juveniles. The results of an additional experiment, in which fertilized eggs and newly hatched larvae were treated with T4 and/or thiourea, suggested the presence of negative feedback regulation of pituitary-thyroid axis, implying an involvement of thyroid hormones even in early premetamorphic larvae. These results suggest that metamorphic climax is induced by a surge of thyroid hormone, and that thyroid hormone may also regulate development before and after the metamorphosis.

Animals↗
PubMed1988

Isolation of genomic DNA controlling mouse melanoma antigen defined by monoclonal antibody.

We have isolated the genomic DNA controlling the expression of murine specific melanoma antigen by employing cosmid shuttle vector and monoclonal antibody. Transfection of the cosmid library derived from mouse melanoma cells into human melanomas and repeated cell sortings of the fluorescence-bright population enabled us to enrich the antigen-positive transfectants. We rescued a 34.8 kb DNA fragment from the transfectants by in vitro packaging and showed it to be responsible for the antigen expression. However, we noticed instability of the antigen expression when the selection pressure imposed by the cell sorting was removed. This seemed to be due to the fact that the insert DNA was preferentially deleted from this cosmid vector without loss of the vector sequence itself.

Animals↗
PubMed1988

Chromosomes and surface markers in lymph node cells from 2 patients with AILD and IBL-like T-cell lymphoma.

Chromosomes and surface markers in lymph node cells from 2 patients with angioimmunoblastic lymphadenopathy associated with dysproteinemia (AILD) or immunoblastic lymphadenopathy (IBL) and with IBL-like T-cell lymphoma, respectively, were examined before treatment. In the patient with AILD, a small clone with chromosome abnormality was found in lymph node cells although a surface marker study failed to demonstrate monoclonality. In this patient, the clinical and cytogenetic findings suggested a subtype of lymphoma with a mild clinical course and a benign histological appearance. In the patient with IBL-like T-cell lymphoma, a high percentage of metaphases showed chromosome abnormalities such as ring chromosomes. The clinical, immunological and cytogenetic findings suggested an aggressive type of lymphoma, even though the histologic appearance was similar to that of IBL.

Adult↗
PubMed1988

[Metastatic calcification associated with malignancy].

From 1975 to 1986, 15 cases (2%) of metastatic calcification associated with an underlying malignancy were found in a review of 702 autopsied cases with histories of malignancy. These underlying malignancies included 7 cases of lung cancer, 6 cases of malignant lymphoma, one case of breast cancer, and one of urinary bladder cancer. Squamous cell carcinoma was of the histological type most often associated with metastatic calcification in lung cancer, and ATL in malignant lymphoma. Hypercalcemia was found in 10 (83%) out of cases, and almost all were accompanied by renal dysfunction. Calcium deposits were most frequently observed in the kidneys and the lungs. It has been suggested that metastatic calcification in the lungs and kidneys of a patient with a history of malignancy showing hypercalcemia is sometimes accompanied by respiratory and renal dysfunction, causing the patient's condition to deteriorate.

Adult↗
PubMed1987

Isolation and characterization of the gene for the murine T cell differentiation antigen and immunoglobulin-related molecule, Lyt-2.

We present here the sequence of the 5310 base pair Hind III-cleaved genomic DNA segment that includes the gene for the Lyt-2, a murine differentiation antigen expressed on most immature T lymphocytes as well as the cytotoxic suppressor T cell subset. We also present the complete intron/exon structure of Lyt-2. There are five exons: a fused leader and immunoglobulin variable region like exon, a hinge region exon, a transmembrane exon and two alternatively spliced intracytoplasmic exons (alternative splicing of these exons yields the 38 kDa alpha and 34 kDa alpha' Lyt-2 polypeptides). The promotor region contains a "TATA" box and sequences homologous to the putative immunoglobulin transcriptional control elements cd/pd. S1 protection analysis reveals that thymocytes, T cells from lymph nodes, and a Lyt-2 transfectant obtained by introduction of total genomic DNA have the same initiation site. In the 3' region, there is a polyadenylation signal sequence after a 700 bp long 3' untranslated region.

Amino Acid Sequence↗
PubMed1987

Presence of thyroxine in eggs and changes in its content during early development of chum salmon, Oncorhynchus keta.

In order to examine the role of thyroid hormones during salmonid development, techniques were developed for quantitative extraction of thyroxine from eggs, whole embryos, and alevins of chum salmon (Oncorhynchus keta) at various stages of development. Frozen eggs, embryos, alevins, or fry were homogenized in ice-cold methanol. The homogenate was centrifuged, and the supernatant was washed with a mixture of chloroform and 0.05% CaCl2. The aqueous layer was lyophilized, and the residue was redissolved in barbital buffer for thyroxine radioimmunoassay (RIA). Serial dilutions of the egg or tissue extracts gave inhibition slopes that were parallel to that of the thyroxine standard in the RIA. Immunoreactivity of the extracts coeluted with thyroxine standard in reverse-phase HPLC on an ODS column. Recovery of thyroxine from egg and tissue extracts was estimated from the recovery of 125I-labeled thyroxine added to the initial homogenates. Thyroxine content of eggs just after fertilization was 4-5 ng/egg, and this level was maintained until hatching. A decrease in thyroxine content was seen during yolk absorption. Total thyroxine increased to about 10 ng/fish, a level higher than that in the unfertilized egg, at the time of complete yolk absorption, and decreased within 10 days to a low level of 1 ng/fish. These findings are discussed in relation to the role of maternal thyroid hormones during early development and also to the onset of larval thyroid function.

Animals↗
PubMed1987

Isochromosome 17q in a case of myelofibrosis with myeloid metaplasia terminating in blastic transformation.

A case of myelofibrosis with myeloid metaplasia in a 61-year-old female patient is reported. Cytogenetic studies were performed using short-term culture without phytohemagglutinin. A chromosomal aberration of an isochromosome 17q, [i(17q)], was revealed in 88% of the metaphases of peripheral blood cells in the blastic phase. However, all metaphases of bone marrow cells in the chronic phase showed a normal karyotype. Furthermore, i(17q) was also observed in 10% of the metaphases of spleen cells examined 8 months before blastic transformation. In this case, therefore, the cells with i(17q) were associated with an abnormal clone of blastic transformation, with the abnormal clone originating in the spleen with myeloid metaplasia.

Aged↗
PubMed1987

Dysmegakaryocytopoiesis in acute leukaemias: its predominance in myelomonocytic (M4) leukaemia and implication for poor response to chemotherapy.

Megakaryocytopoiesis was morphologically investigated in 129 adults with de novo acute leukaemia. Three types were identified: type I (84 cases), no detectable megakaryocytes; type II (32 cases), quantitatively preserved megakaryocytes with normal morphology; type III (13 cases); quantitatively preserved megakaryocytes but with distinct dysplastic changes such as micromegakaryocytes and megakaryocytes with multiple small separated nuclei. Type III was found in M1 (one out of 21 cases), M2 (one out of 20 cases). M4 (eight out of 24 cases), M6 (two out of four cases) and hypoplastic leukaemia (one out of 13 cases). M3 cases were all classified into type I. Most of acute lymphoid leukaemia cases (21 cases) belonged to type II. Among AML cases, the complete remission (CR) rate by intensive chemotherapy with daunorubicin and cytosine arabinoside was significantly lower in type III (11%) than in types I (87%) and II (71%). Among M4 cases, CR rates in type III (14%) was also significantly lower than those in type I (75%) and II (100%). Thus, the present study indicates the importance of recognizing dysmegakaryocytopoiesis in AML for clarification of the heterogeneous biology or pathophysiology of acute leukaemias and formulation of an appropriate therapeutic strategy.

Acute Disease↗
PubMed1987

Duck hepatitis B virus replicates in the yolk sac of developing embryos.

Duck hepatitis B virus (DHBV) is the only member of the hepadnavirus family in which nearly 100% vertical transmission from carrier mother to embryo has been reported. Large quantities of maternally transmitted virus particles are present in the yolk prior to incubation of the eggs, and replicative forms of DHBV DNA are detectable in the liver at 6 days of incubation. Since the yolk sac is similar to the liver in its production of serum proteins, we examined the yolk sacs of developing embryos for signs of viral replication. We detected the supercoiled form of DHBV DNA, DHBV RNA transcripts similar to those in the virus-replicating liver, and DNA polymerase activity and viral DNA in corelike particles in extracts of yolk sac tissue of naturally infected eggs. DHBV core antigen was strongly stained in only the endodermal layer of the yolk sac by immunofluorescence. DHBV RNA was detectable in the yolk sac from 4 days of incubation until hatching, and a larger quantity of DHBV RNA was present in the yolk sac than in the liver during all the stages of embryogenesis. Our data indicate that DHBV replicates actively in the yolk sac from an earlier stage than that previously reported in studies of embryonic liver and that replication is limited to the endodermal cell layer, which is ontogenetically and functionally related to the liver. The yolk sac may support the vertical transmission of DHBV.

Animals↗