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Biomedical subjects

M Tagawa

Publications and source records attributed to M Tagawa.

At least 235 records · Page 13Linked to original sources
PubMed1987

Lymphographic changes in young dogs after transplantation with adult worms of Dirofilaria immitis into the abdominal cavity.

Serial lymphographic studies were made in 4 dogs transplanted with adult worms of Dirofilaria immitis. Several changes of the lymphatic systems of the treated dogs such as dilatation, narrowing, tortuosity, backflow, collateral flow, leakage and lymphorrhea of lymphatics, as well as enlargement and filling defect of lymphnodes were observed at first 2 months after transplantation, comparing with the lymphograms before transplantation. Lymphographies were repeated further 4 and 7 months after transplantation. In our previous studies, the mechanism of chyluria due to human filariasis was not sufficiently explained beyond the speculation of the mechanical obstruction of lymphatic vessels by worm bodies. In the present studies, varied abnormal changes, especially back and collateral flow of the lymph vessels of popliteal and inguinal regions, could be produced in lymphatic systems in dogs by transplantation with adult worms of Dirofilaria immitis into peritoneal cavity. This fact suggests that a mechanism of filarial chyluria is due to systemic responses and changes of the lymphatics by substance of the body of filarial worms.

Animals↗
PubMed1987

Leukemic blast cell colony formation in semisolid culture with erythropoietin: a case report of acute poorly differentiated erythroid leukemia.

The bone marrow of a patient with acute undifferentiated leukemia developed unique colonies after a 14-day culture in erythropoietin (EPO)-containing methylcellulose. The colonies consisted of 20 to 200 nonhemoglobinized large blast cells. Cytogenetic analysis of single colonies revealed hypotetraploid karyotypes with several marker chromosomes that were identical to those found in directly sampled bone marrow. The concurrently formed erythroid bursts showed only normal karyotypes. No leukemic colony formation was observed in other culture systems with either colony-stimulating activity (CSA) or phytohemagglutinin-stimulated leukocyte-conditioned medium (PHA-LCM). The leukemic colonies exhibited a complete EPO-dose dependency similar to that of the patient's normal BFU-E. Although cytochemical and immunologic marker studies of the bone marrow cells failed to clarify the cell lineage of the leukemic cells with extraordinarily large cell size, ultrastructural study revealed erythroid differentiation such as siderosome formation in the cytoplasm and ferritin particles in the rhophecytosis invaginations. These findings indicate that the patient had poorly differentiated erythroid leukemia and that some of the clonogenic cells might respond to EPO in vitro. Corresponding to this biological feature, the leukemic cells were markedly decreased in number in response to repeated RBC transfusions, and partial remission was obtained. These observations suggest that erythroid leukemia distinct from erythroleukemia (M6) with a myeloblastic component, can develop as a minor entity of human acute leukemia.

Acute Disease↗
PubMed1986

Significance of chromosome 14 anomaly at band 14q11 in Japanese patients with adult T-cell leukemia.

The chromosomes of leukemic blood cells in eight Japanese patients with acute adult T-cell leukemia (ATL) were examined by a direct method or short-term culture method without any mitogens. Six patients showed a chromosome 14 anomaly with a break at band q11-13: inv(14)(q11q32) in two patients, t(11;14)(p13;q13) in one patient, t(14;14)(q11;q32) in addition to del(14)(q11q13) in another, and only del(14)(q11q13) in two patients. Thus, a proximal 14q rearrangement exists in ATL as in other types of T-cell malignancies. Based on these facts, the pathogenesis of ATL is discussed in reference to the literature.

Chromosome Aberrations↗
PubMed1986

Appearance of viral RNA transcripts in the early stage of duck hepatitis B virus infection.

Sequential analysis of duck hepatitis B virus (DHBV) DNA and RNA transcripts in the liver of the early stage of infection was carried out using 1-day-old ducklings inoculated with DHBV-positive serum. Using Southern blot analysis, a band of supercoiled DHBV DNA was detectable at 6 hr, when DHBV-specific poly[A]+RNA was also observed by Northern blot analysis as a faint smear below 3-kb. Bands of RNA at 3.5, 2.7, and 2.5 kb were detected at 12 hr, just before single-stranded viral DNA was detected. A prominent increase in the amount of viral RNA was demonstrated (between 12 hr and 3 days) prior to the increase of DHBV DNA (between 3 and 6 days). Our results suggest that 3.5-kb DHBV-specific RNA synthesized from supercoiled DNA may act as a template of reverse transcription, and that all steps of the replication pathway proposed by Summers and Mason (1982, Cell, 29, 403-415) are completed during 3 days.

Animal Diseases↗
PubMed1986

Formal proof that different-size Lyt-2 polypeptides arise from differential splicing and post-transcriptional regulation.

We recently isolated the gene and a cDNA clone for the mouse T-cell surface antigen Lyt-2 and showed that Lyt-2 is homologous to the human Leu-2 (T8) antigen and that the gene encoding it is a member of the immunoglobulin gene superfamily. By screening a mouse thymus cDNA library with the Lyt-2 cDNA clone, we isolated two classes of cDNA clones, alpha and alpha', which differ by 31 base pairs. Comparison of the alpha cDNA with genomic sequence data indicates that there are five exons encoding Lyt-2: a fused leader/immunoglobulin variable region-like exon, a spacer region exon, a transmembrane exon, and two cytoplasmic exons. The alpha' cDNA clones lack the first of the two cytoplasmic exons and have a direct splice from the donor splice site of the transmembrane exon to the acceptor of the second cytoplasmic exon. This splice changes the reading frame for the second cytoplasmic exon, causing a stop codon shortly after the splice so that the alpha' cDNA clone codes for a peptide 25 residues shorter than the alpha cDNA-encoded peptide. We have constructed expression vectors with alpha and alpha' cDNAs and have shown that L-cell transfectants of these produce Lyt-2 polypeptides of the predicted sizes and that these associate as homodimers on the cell membranes. We found the two species of mRNA corresponding to alpha and alpha' cDNAs at equal levels in thymus RNA by using S1 nuclease analysis. Although lymph node T cells have only the alpha form of Lyt-2 protein, S1 nuclease analysis shows that lymph nodes have about 20% alpha' mRNA relative to alpha. Thus, Lyt-2 is regulated at RNA processing, translational, and/or post-translational steps.

Animals↗
PubMed1985

Syngeneic monoclonal antibody against melanoma antigen with interspecies cross-reactivity recognizes GM3, a prominent ganglioside of B16 melanoma.

It has previously been reported that a mouse (C57BL/6) monoclonal antibody, M2590, was established against syngeneic melanoma B16 cells, which was shown to react only with melanoma cells from various species but not with other tumor cells or normal tissues (Taniguchi, M., and Wakabayashi, S. (1984) Gann 75, 418-426). In the present study, the specificity of M2590 antibody was shown to be directed to a saccharide arrangement (NeuAc alpha 2-3Gal beta 1-4Glc (or -GlcNAc)) of gangliosides by three different assay systems including enzyme immunostaining on thin layer plates, sandwich radioimmunoassay, and enzyme-linked immunoadsorbent assays using a variety of glycolipids with known structures. Neither gangliosides having NeuGc terminus, including NeuGc alpha 2-3Gal beta 1-4Glc-ceramide and NeuGc alpha 2-3Gal beta 1-4GlcNAc beta 1-3Gal beta 1-4Glc-ceramide, nor ganglio series gangliosides carrying NeuAc reacted with the antibody. An M2590 antibody-reactive antigen was isolated from B16 melanoma cells, and its structure was determined to be NeuAc alpha 2-3Gal beta 1-4Glc-ceramide by fast atom bombardment mass spectrometry, methylation analysis, and exoglycosidase treatment. The ceramide was composed of d18:1 as its long-chain base and C16:0, C24:1, and C24:0 as major fatty acids. The same ganglioside was also detected in the culture supernatant of the melanoma cells as shedding antigen.

Animals↗
PubMed1985

Expression in E. coli of finger-domain lacking tissue-type plasminogen activator with high fibrin affinity.

Tissue-type plasminogen activator (t-PA) has a high affinity for fibrin and induces lysis of fibrin (fibrinolysis) on the surface of fibrin without degrading circulating fibrinogen. cDNA for t-PA which lacks the 'finger-domain' (the site for fibrin affinity) was isolated from Detroit 562 cells. Analysis of the nucleotide sequence revealed a lack of the sequences which code for the finger-domain. A plasmid (pDPAT 1) containing the Escherichia coli tac promoter/operator and the cDNA sequence coding for 'finger-domain lacking t-PA' was constructed for expression in E. Coli. The polypeptide so produced was a new type of t-PA lacking finger-domain, but revealed plasminogen activator activity with the function of fibrin affinity.

Amino Acid Sequence↗
PubMed1985

A comparative study of immunological and cytochemical profiles between adult and childhood acute lymphoblastic leukemias (ALLs): heterogeneity in adult common ALL.

To investigate the biological differences between adult and childhood acute lymphoblastic leukemia (ALL), leukemic blasts from 33 patients with ALL (22 adults and 11 children) and from 11 patients in the lymphoid crisis of chronic myeloid leukemia (CML) were studied using cytochemical and immunological markers and also by the outcome of their treatment. The cytochemical studies showed that blasts from seven of the adult ALL patients were dense-granular-positive (DG-positive) for beta-glucuronidase, whereas the blasts from the children were negative except for one (with T-ALL). In the adults with common ALL (cALL), survival of patients DG-positive for this enzyme were significantly shorter than that of eight patients with a scattered granular pattern (p less than 0.05). The mean ratio between the percentage of blasts positive for cALL antigen (cALLA) to that of blasts positive for terminal deoxynucleotidyl transferase (TdT) in the adult group with cALL (0.6 +/- 0.3) was significantly lower (p less than 0.01) than in the group of children with cALL (1.1 +/- 0.2) or in the lymphoid-crisis group (1.5 +/- 1.0). These findings indicate that adult cALL consists of two distinct subpopulations, one with less differentiated phenotype (cALL-/TdT+) and the other with more (cALL+/TdT+). In contrast, the blast cells in childhood cALL and some patients in lymphoid crisis had a relatively homogeneous population with the latter phenotypes. The results suggest that the clonotypic cells in adult ALL, particularly in cALL, appear to be more immature than those in childhood ALL. The beta-glucuronidase patterns indicate a further heterogeneity in adult ALL.

Adolescent↗
PubMed1985

Low-dose cytosine arabinoside regimen induced a complete remission with normal karyotypes in a case with hypoplastic acute myeloid leukaemia with No. 8-trisomy: in vitro and in vivo evidence for normal haematopoietic recovery.

Complete remission was achieved in a case of hypoplastic acute myeloid leukaemia with chromosomal aberration of No. 8-trisomy by giving very low dose of cytosine arabinoside (ara-C), 10 mg (7 X 5 mg/m2)/d, by 24 h continuous intravenous infusion for 20 d. We observed a definite cytoreduction phase in the bone marrow (BM) before normal haematopoiesis resumed. The remission BM showed only normal karyotypes in all metaphases examined. Granulocyte/macrophage colonies and erythroid bursts recovered sufficiently in numbers and cytogenetic study on single colonies and bursts revealed only normal karyotypes. These observations provide evidence that a low dose ara-C regimen can induce remission by cytoreduction which diverts the growth advantage from the leukaemic clone to the normal clones.

Chromosomes, Human, 6-12 and X↗