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Biomedical subjects

N Maeda

Publications and source records attributed to N Maeda.

At least 649 records · Page 36Linked to original sources

The decreased membrane fluidity of in vivo aged, human erythrocytes. A spin label study.

The decreased membrane fluidity of the in vivo aged, human erythrocytes is found, by monitoring the electron paramagnetic resonance (EPR) spectra of fatty acid spin labels incorporated into the membrane. In addition, the decreased cell sizes and the decreased cholesterol and phospholipids contents, without significant changes of the quantity of the membrane proteins, also the decrease of ATP and 2,3-diphosphoglycerate and the increase of ADP and AMP, in the aged cells, were observed. Further the functional impairments of the aged cells, i.e. the increased oxygen affinity and the decreased deformability, were shown. On the basis of these quantitative data, the alteration of the protein-lipid organization, due to decreased lipid/protein ratio, the modified protein-lipid interaction and/or the influences of the diminished ATP content, is suggested to contribute towards the decreased membrane fluidity of the in vivo aged erythrocytes.

Adenine Nucleotides↗

Fine structure of a glomus tumor of the tongue and expression of C type virus in its tumor cells.

A glomus tumor in the tongue of a 29-year-old Japanese male is presented. Ultrastructural examination demonstrated this tumor to be composed of the tumor cells having structural features in common with smooth muscle cells, and mast cells as the less frequent type cell. Moreover, a small number of C type virus particles were found to be in the cytoplasm or in the intercellular spaces. In this communication, besides the detailed description of the morphology of the glomus tumor, the possible involvement of C type virus in processes of tumor formation is discussed.

Adult↗

Attenuated mumps virus therapy of carcinoma of the maxillary sinus.

This paper presents treatment of carcinoma of the maxillary sinus with an attenuated mumps virus. The mumps virus was inoculated into two cases of very advanced carcinoma of the maxillary sinus by local and general injection. Shortly after injection, relief from severe cancer pain and growth inhibition or necrosis of tumor were observed in both cases. In this communication, we discuss a possible mechanism of antitumor effect of mumps virus by utilizing immunologic tests and interferon assay.

Carcinoma, Squamous Cell↗

Immunological features and corticosteroid therapy of midline granuloma.

This paper presents treatment of midline granuloma with corticosteroids and immunological features of this disease. The cellular immunity state of this patient was examined by counting T cell subpopulation and lymphocyte blastformation index (BI) by phytohemagglutinin at various time intervals during the corticosteroid therapy. Consequently, the percentage of T cells and BI became greatly increased according to the subsiding of the primary lesion, whereas non-T cell production and its function were depressed. In this communication we discuss a possible autoantibody mechanism and impared lymphocyte transformation in midline granuloma.

Cheek↗

A kinetic measurement of red cell deformability: a modified micropipette aspiration technique.

A kinetic measurement of the red cell deformability is developed, modifying the micropipette aspiration technique of BRAASCH (1971). The sedimented human red cells on a slide-glass are individually aspirated into a micropipette by negative pressure (delta P), and the decreasing "velocity (v)" of the applied electric current, due to the aspirating cell, is taken as a measure of the "easiness" of the cell to enter into the small orifice of the micropipette (inner diameter, 2 R congruent to 3 micrometer). An empirical relation, v infinity (pi r2) . (delta P) . ("deformability"), is obtained. In order to test the validity of the method, some factors influencing the deformability are studied: i.e., the "velocity" decreases as lowering temperature; the "velocity" of the glutaraldehyde-pretreated cells and of both in vivo and in vitro aged cells decreases. Therefore, the parameter, "velocity (v)," reflects the deformability well. In addition, if a few assumptions could be allowed, v would be related to the Young's modulus of the membrane.

Erythrocyte Aging↗

Three neurotoxins from the venom of a sea snake Astrotia stokesii, including two long-chain neurotoxic proteins with amidated C-termini.

From the venom of a sea snake Astrotia stokesii three neurotoxic components, toxins Astrotia stokesii a, b and c were isolated in 40, 15 and 5% yield by weight respectively of the whole venom. Their LD50 values for 20g mice were 0.13, 0.096 and 0.098 microgram/g body wt. respectively and accounted for almost all the lethal activity of the venom. Their amino acid sequences were determined. Astrotia stokesii a was composed of 60 amino acid residues with nine half-cystine residues and was quite homologous to other sea-snake short-chain neurotoxins in its amino acid sequence. Toxins Astrotia stokesii b and c were composed of 70 and 72 amino acid residues respectively with 10 half-cystine residues. They are the first long-chain neurotoxins with high activity isolated from sea-snake venoms. The C-terminal carboxy groups of toxins b and c were found to be amidated; the amidation is known for some polypeptides, but is novel for a protein. The amide group may make a hydrogen-bond with glutamic acid-39, which replaces a lysine that has so far been found invariably in long-chain neutrotoxins. Astrotia stokesii b and c are also novel in having phenylalanine-25 and isoleucine- or valine-42. The ordinary Tyr-Glu pair, which is observed in X-ray structure [Low, Preston, Sato, Rosen, Searl, Rudko & Richardson (1976) Proc. Natl. Acad. Sci. U.S.A. 73, 2991-2994] and n.m.r.study [Inagaki, Tatsumi, Miyazawa, Hori & Tamiya (1977) Abstr. Int. Congr. Pure Appl. Chem. 26th, p. 336] on erabutoxins may be replaced by a hydrophobic pair. Detailed evidence for the amino acid sequences of the proteins has been deposited as Supplementary Publication SUP 5009o (30 pages) at the British Library Lending Division, Boston Spa, Wetherby, West Yorkshire LS23 7B1, U.K., from whom copies can be obtained on the terms indicated in Biochem. J. (1978) 169, 5.

Amides↗

Isolation and characterization of a new rubella variang with DNA polymerase activity.

A rubella variant (HPV-RV) was isolated from high passage rubella virus preparations propagated at 37 degrees C in baby hamster kidney BHK21/WI-2 cells. HPV-RV formed clear plaques in HeLa cells and primary cells of the Rhesus monkey kidney although wild type rubella virus did not produce plaques in these cells. Cells persistently infected with rubella virus were insensitive to infection by HPV-RV at both 34 degrees and 39.5 degrees C. HPV-RV agglutinated one day old chick, human group O and sheep erythrocytes. This hemagglutinating activity was inhibited by anti-BHK latent virus serum but not by anti-rubella virus serum. The plaque forming ability of HPV-RV was neutralized by anti-BHK latent virus serum although the same antiserum did not affect the plaque forming ability of wild type rubella virus. Furthermore, HPV-RV was found to have the complement fixation antigen of rubella virus and DNA polymerase activity. From these findings, it is concluded that HPV-RV is a hybrid between rubella virus and a latent virus of BHK21/WI-2 cells.

Antigens, Viral↗