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Biomedical subjects

M Seki

Publications and source records attributed to M Seki.

At least 325 records · Page 18Linked to original sources
PubMed1989

[A rare case of left atrial thrombus after left upper pulmonary lobectomy].

A 75-year-old man was operated for left atrial thrombus. He had received left upper pulmonary lobectomy for epidermoid carcinoma of the lung, 6 months previously. Thrombus, 5.2 X 1.5 X 0.8 cm in size, was grown up from the inside of the left upper pulmonary vein into the left atrial cavity. It was removed and left upper pulmonary vein orifice was sutured and closed. There was no abnormal findings in the endocardium of the left atrium and mitral valve. A case of the left atrial thrombus after the pulmonary lobectomy is very rare and this may be the first report in world literature.

Aged↗
PubMed1988

Further characterization of DNA helicase activity of mouse DNA-dependent adenosinetriphosphatase B (DNA helicase B).

The DNA helicase activity of DNA-dependent ATPase B purified from mouse FM3A cells [Seki, M., Enomoto, T., Hanaoka, F., & Yamada, M. (1987) Biochemistry 26, 2924-2928] has been further characterized. The helicase activity was assayed with partially duplex DNA substrates in which oligonucleotides to be released by the enzyme were radiolabeled. Oligonucleotides with or without phosphate at the 5' termini or with a deoxy- or dideoxyribose at the 3'-terminal nucleotides were displaced by this enzyme with essentially the same efficiency and with the same ATP (and dATP) and Mg2+ requirements. Thus, there was no strict structure requirement for both ends of duplex regions of substrates to be unwound by the enzyme. Shorter strands were released more readily than longer strands up to the length of 140 bases. The attachment of the enzyme to a single-stranded DNA region was a prerequisite for the neighboring duplex to be unwound; the enzyme-catalyzed unwinding was inhibited competitively by the coaddition of single-stranded DNAs which act as cofactors of the ATPase activity. Their activities as the inhibitor of helicase were well correlated with those as the cofactor of ATPase. The helicase B was found to migrate along single-stranded DNA in the 5' to 3' direction by the use of single strands with short duplex regions at both 3' and 5' ends as substrate. A possible role of this enzyme in DNA replication in mammalian cells is discussed.

Adenosine Triphosphatases↗
PubMed1988

Production of interleukin-3 from a T-cell neoplasm.

We have established a new T-cell line (CL-8313) that produces interleukin-3 from the spleen cells of mice with a radiation-induced myeloproliferative disorder. IL-3 activity was detected at an extremely high level in the culture medium of the CL-8313 cell line in the absence of any exogenous stimulator. A large amount of IL-3 transcript also was demonstrated in CL-8313 cells. BPA- and CSF-activity was detected at a high level in the culture medium of the CL-8313 cell line. Southern blot analysis of high molecular weight DNA from the CL-8313 cells showed they had unique rearrangement of the antigen receptor beta chain gene. Therefore, we concluded that CL-8313 cells belonged to T-lineage lymphocytes and constitutively produced a high level of IL-3.

Animals↗
PubMed1988

Synthesis of ethyl 2-(4-chlorophenyl)-5-(2-furyl)-4-oxazoleacetate, a hypolipidemic agent, and related compounds.

A series of 2-aryl and 2-alkyl derivatives of 5-furyl-4-oxazoleacetic acid and their homologues having alkyl groups at the alpha-position of the acids were synthesized and evaluated for their hypolipidemic activities in Sprague-Dawley rats. On the basis of the structure-activity relationships and subacute toxicities, ethyl 2-(4-chlorophenyl)-5-(2-furyl)-4-oxazoleacetate (35) was selected as a candidate compound for development. Compound 35 reduced serum cholesterol and triglyceride levels by 23% and 35%, respectively, at a dose of 0.05% in a diet in normal rats, and it was about 10 times more active in hereditary hyperlipidemic rats (THLR/1) than in normal rats. Compound 35 inhibited platelet aggregation in vitro and also normalized hyperaggregability of hyperlipidemic plasma platelet ex vivo.

Animals↗
PubMed1988

Production of succinic Acid from citric Acid and related acids by lactobacillus strains.

A number of Lactobacillus strains produced succinic acid in de Man-Rogosa-Sharpe broth to various extents. Among 86 fresh isolates from fermented cane molasses in Thailand, 30 strains (35%) produced succinic acid; namely, 23 of 39 Lactobacillus reuteri strains, 6 of 18 L. cellobiosus strains, and 1 of 6 unidentified strains. All of 10 L. casei subsp. casei strains, 5 L. casei subsp. rhamnosus strains, 6 L. mali strains, and 2 L. buchneri strains did not produce succinic acid. Among 58 known strains including 48 type strains of different Lactobacillus species, the strains of L. acidophilus, L. crispatus, L. jensenii, and L. parvus produced succinic acid to the same extent as the most active fresh isolates, and those of L. alimentarius, L. collinoides, L. farciminis, L. fructivorans (1 of 2 strains tested), L. malefermentans, and L. reuteri were also positive, to lesser extents. Diammonium citrate in de Man-Rogosa-Sharpe broth was determined as a precursor of the succinic acid produced. Production rates were about 70% on a molar basis with two fresh strains tested. Succinic acid was also produced from fumaric and malic acids but not from dl-isocitric, alpha-ketoglutaric, and pyruvic acids. The present study is considered to provide the first evidence on the production of succinic acid, an important flavoring substance in dairy products and fermented beverages, from citrate by lactobacilli.

Journal Article↗
PubMed1988

Homogeneous liposome lysis assay for determination of anti-streptolysin O antibody titer in serum.

We developed a liposome lysis assay for determining anti-streptolysin O antibodies (ASO) in human sera involving the use of carboxyfluorescein-entrapped multilamellar liposomes. This assay system was based on the inhibition of streptolysin O-induced liposome lysis by ASO. Briefly, after incubation of a given amount of streptolysin O with ASO for 30 min at 37 degrees C, carboxyfluorescein-entrapped liposomes composed of egg yolk phosphatidylcholine and cholesterol in a molar ratio of 1:1 were added to the mixture to determine the residual streptolysin O activity. Liposome lysis, detected as carboxyfluorescein release from the liposomes, was inversely proportional to the ASO titer. The results of within-run and between-run precision studies indicated that the liposome lysis assay is accurate and gives reproducible data. Bilirubin, hemoglobin, and triglycerides did not interfere with the liposome lysis assay. The ASO titers of 100 patient sera, evaluated by our new method and the Rantz-Randall method, showed good correlation.

Antistreptolysin↗