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Biomedical subjects

S Maeda

Publications and source records attributed to S Maeda.

At least 991 records · Page 55Linked to original sources
PubMed1981

Primary hemangiopericytoma of the heart. A case report.

Hemangiopericytoma (HP) represents a rare cellular vascular tumor. The present report of primary HP of the heart in a 53-year-old Japanese male is the first of its kind. Most of the tumor masses were removed, but masses tightly adhering to both the pericardium and the epicardium were not excised because of profuse bleeding. The patient has remained free of complaints for 10 months post-operatively. Non-invasive methods including a chest X-ray, echocardiogram, and thallium-201 myocardial imaging were found to be useful adjuncts of the diagnosis of cardiac tumor.

Heart Neoplasms↗
PubMed1981

Hormone dependency of chromosome aberrations induced by 7,12-dimethylbenz[a]anthracene in rat bone marrow cells: site-specific increase by erythropoietin.

The frequency of chromosome aberrations (CA) 6 hours after iv injection of 50 mg 7,12-dimethylbenz[a]anthracene (DMBA)/kg was studied in bone marrow cells of the noninbred Long-Evans rat under various hematopoietic conditions. The percentage of metaphase cells with CA was enhanced by anemia and suppressed by polycythemia. The low incidence of CA in polycythemic rats was reversed by 6 U of sheep erythropoietin (EP) injected at the time of DMBA treatment. The interchromosomal and intrachromosomal distribution of CA indicated that hematopoietic stimuli, more specifically EP, greatly enhanced DMBA-induced CA in specific chromosomal regions.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1981

Chemical carcinogenesis in the rat: common mode of action of carcinogens at the chromosome level.

The chromosomal distribution of chromosome aberrations (CA) and sister chromatid exchanges (SCE) induced by various chemical carcinogens such as 7,12-dimethylbenz[a]anthracene, 7,8,12-trimethylbenz[a]anthracene, 1-butyl-1-nitrosourea, urethan, 4-nitroquinoline 1-oxide, 2-(2-furyl)-3-(5-nitro-2-furyl)acrylamide, and the antineoplastic compound mitomycin C was studied with the use of noninbred Long-Evans male rat bone marrow cells in vivo and in vitro. The CA and SCE induced by these structurally different chemicals were distributed in a similar pattern among and along chromosomes when the chemicals were given a short time (6 hr) before the metaphase cells were harvested. The specific distribution pattern of chemically induced CA and SCE along chromosomes was attributed to the late DNA replication of the vulnerable chromosome regions. Conversely, X-ray-induced CA were distributed more randomly. Thus the different chemical carcinogens were shown to exert a similar genetic effect at the chromosome level.

Animals↗
PubMed1980

Human leukocyte interferon produced by E. coli is biologically active.

A human leukocyte interferon cDNA was enzymatically synthesized, inserted into the vector pBR322, and cloned in Escherichia coli. The DNA sequence codes for a 23-amino acid signal peptide followed by an interferon polypeptide of 165 amino acids. An expression plasmid was constructed which permits the synthesis in E. coli of 2.5 x 10(8) units of interferon per litre of culture. This LeIF protected squirrel monkeys from lethal encephalomyocarditis virus infection.

Amino Acid Sequence↗
PubMed1980

The development of mucosal immunity in guinea pig middle ears.

Recent studies have suggested to us that the middle ear is an organ capable of responding immunologically to antigenic substance. However, it is still not known when and how the middle ear starts to provide the immunologic defense system. To clarify this, we investigated immunoglobulin forming cells of different classes and secretory proteins, such as secretory component and lactoferrin, in the mucous membrane of eustachian tube and tympanic bulla of 20 developing and 5 normal adult guinea pigs by the use of a direct immunofluorescence technique. Other organs, such as nose, larynx, trachea, small intestine, spleen and lymph node were also subjected to this investigation. Changes in the middle ear mucosa were also observed after antigenic challenges directly to the tympanic cavity of 6 developing and 39 adult guinea pigs. IgA and IgM forming cells began to appear in the tubal mucosa on 7th postnatal day, wile it was scarcely possible to find IgG1 and IgG2 forming cells in developing guinea pigs. Immunoglobulin forming cells of all classes increased in the middle ear mucosa after the antigenic stimuli. Results of this study showed that local synthesis of IgA, as well as other classes, is latent in the middle ear, that the middle ear of immature animals is vulnerable to antigenic stimuli, and that the middle ear of developing animals possesses potential immune responsiveness.

Animals↗
PubMed1980

A novel ColE1::Tn3 plasmid vector that allows direct selection of hybrid clones in E. coli.

A plasmid, named pKY2289, consists of a whole ColE1 DNA molecule and a complete ampicillin transposon (Tn3). When induced, E. coli K-12 cells which carry pKY2289 promote synthesis of colicin E1, but they are not immune to colicin E1. Inserting a DNA fragment into the EcoRI or the XmaI site of this plasmid abolishes its ability to produce active colicin E1. Thus, cells carrying one of these in vitro recombinant pKY2289 plasmids are able to form normal colonies in the presence of 0.1 microgram/ml of mitomycin C and 50 microgram/ml of ampicillin, while cells carrying the parental pKY2289 form very tiny colonies under the same conditions. This allows a positive selection for an in vitro recombinant pKY2289 molecule carrying a foreign DNA insertion. The properties of cells carrying the original pKY2289 are described and its potential usefulness as a cloning vehicle is demonstrated by cloning all the EcoRI and XmaI fragments of lambda DNA.

Ampicillin↗
PubMed1980

Construction and identification of bacterial plasmids containing nucleotide sequence for human leukocyte interferon.

Bacterial plasmids containing human leukocyte interferon sequences were constructed and identified. Identification was confirmed by correspondence of the nucleotide sequence with out amino acid sequence of human leukocyte interferon. The finding of bacterial recombinants containing distinct leukocyte interferon sequences is consistent with our purification of different leukocyte interferon species. We conclude that what has been designated human leukocyte interferon is, indeed, a class of homologous proteins. Preliminary indications suggest that their diversity appears to be represented by individual genomic equivalents. Each of the individual species exhibits characteristic activities. The structural modulation of these biological activities has immense significance for understanding the natural role of the interferons and for refining and developing their ultimate therapeutic potential.

Base Sequence↗
PubMed1980

Psychiatric symptoms in ruptured anterior communicating aneurysms: social prognosis.

Pre- and postoperative psychiatric symptoms were compared in 85 patients with anterior communicating aneurysms and 73 of these cases were followed up to determine the long-term results. Psychiatric symptoms of varying severity were present preoperatively in 61 % of the cases, which decreased to 34 % after surgery. Use of the microsurgery microscope resulted in a no change: aggravation:mortality ratio of 27:5:0, as compared with 33:20:4 when the microscope was not used.

Adult↗
PubMed1980

Effects of long-term ozone exposure and dietary vitamin E in rats.

Rats fed on a vitamin E-deficient diet (E-depleted group) and a vitamin E-supplemented diet (E-supplemented group) were exposed to 0.3 ppm ozone for three hours daily, five days a week for seven months. Then animals from each group were sacrificed, and electron microscopic studies on the lung and biochemical examinations on the lung and liver were performed. 1) Vitamin E concentration in serum decreased following ozone exposure in the E-supplemented group, whereas it remained unaffected the E-depleted group. 2) Both TAB value and % release of lysosomal enzyme (acid phosphatase) of the liver were increased in vitamin E-depleted air-exposed rats, and showed even higher values following ozone exposure. Levels of both components were highest in the vitamin E-depleted ozone-exposed rats, thus demonstrating that there are a marked increase in lipid peroxide and the increased labilization of lysosomes in this instance. 3) Arachidonic acid (20:4) of total lipid, phospholipid and lecithin in the lung tissue showed a tendency to decrease in vitamin E-depleted air-exposed rats. Those in the ozone-exposed animals showed in both groups a tendency to increase in total lipid and lecithin, and to decrease in phospholipid. However, a change in the fatty acid composition following ozone exposure was generally mild. 4) The fatty acid composition of phospholipid in lung washings did not show a remarkable change following ozone exposure in either group, thus suggesting that it has the resistivity to oxidation. 5) Morphological observations on the lung with the scanning and transmission electron microscopes did not reveal any clear differences between the two groups. The defensive effect of vitamin E on ozone toxicity induced by long-term exposure to ozone was not made clear by the morphological or biochemical examination of the lung. However, biochemical findings in liver of rats exposed to ozone suggested the possibility that vitamin E deficiency permits the damaging effects of lipid peroxidation on biological membranes.

Animals↗
PubMed1980

The effects of mucolytic agents and stirring on sputum viscoelasticity.

Changes in the behavior of sputum viscoelasticity due to differences in macroscopic appearance of sputum brought about by stirring and those due to the addition of an expectorant to purulent sputum in vitro, were studied in a coaxial cylinder rheometer. First, initial results from stirring the sputum indicated the following: Samples of untreated sputum showed no obvious differences among the three macroscopic groups, mucoid, mucopurulent and purulent, on the basis of dynamic viscoelasticity. However, when they were stirred sufficiently, dynamic viscosity and storage modulus increased in mucoid sputum and decreased in purulent sputum. Second, the addition of expectorants revealed the following results: (i) When distilled water was used as a control substance added to sputum, the addition of 0.5% semialkaline proteinase to sputum decreased the dynamic viscosity and storage modulus of the sputum to a large extent. (ii) The addition of 0.2% Bromhexine exerted a small influence upon the dynamic viscosity and slightly increased the storage modulus. (iiii) The addition of 20% N-acetyl-L-cysteine increased the dynamic viscosity slightly, but decreased the storage modulus to a large extent. In brief, each expectorant exerted a unique influence on the viscoelasticity of sputum. These results were discussed with regard to their clinical significance.

Elasticity↗
PubMed1980

Establishment and chromosome studies of in vitro lines of chemically induced rat erythroblastic leukemia cells.

Eight cultured lines with a normal diploid karyotype, no. 2 trisomy, and markers involving chromosome No. 2 were established from three 7,12-dimethylbenz[a]anthracene (DMBA)- and two N-butyl-N-nitrosourea (BNU)-induced erythroblastic leukemias in noninbred Long-Evans rats. Serial in vivo and in vitro passage of these cells frequently evoked karyotype changes in stemline cells. In both lines from DMBA- and BNU-induced leukemias, ordinary and translocation no. 2 trisomy cells appeared and gradually replaced the normal diploid stemline cells. Obvious secondary karyotypic changes were also recognized in the "cloned" leukemia cells. Nucleolar chromosomes such as chromosomes no. 3 and no. 12 were frequently involved in aneuploidy and translocation. One cell line from a BNU-induced leukemia did not change its normal diploid karyotype during 12 months of in vitro passage. The above preferential growth of cells with no. 2 trisomy and the related changes during in vivo and in vitro passage as well as in-colony formation in soft agar suggest that these chromosome changes are somehow associated with the growth behavior of the leukemia cells. No positive correlation was demonstrated between karyotype and dimethyl sulfoxide-induced erythroid differentiation of the leukemia cells.

9,10-Dimethyl-1,2-benzanthracene↗