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Biomedical subjects

M Ohtsu

Publications and source records attributed to M Ohtsu.

44 records · Page 3Linked to original sources
PubMed1984

Genetic analysis of control of proliferation in fibroblastic cells in culture. I. Isolation and characterization of mutants temperature-sensitive for proliferation or survival of untransformed diploid rat cell line 3Y1.

Mutants temperature sensitive for proliferation or survival were isolated from an untransformed diploid clone of fibroblastic rat cells (3Y1), according to an isolation protocol that selected for mutants defective at 38.5 degrees C (selection temperature) in undergoing the transition from quiescent to proliferating state while maintaining viability at 38.5 degrees C. Of the 108 temperature-sensitive clones isolated, 32 were examined for survival in sparse cultures at 39.8 degrees C (nonpermissive temperature) and classified into four classes. Results of temperature shift-up experiments suggest that functions defective in 11 of the 32 mutants are necessary not only for changing from the quiescent to proliferating state but also for maintenance of the proliferating state. Of the 32 mutants, 17 were assigned to eight complementation groups. Results of the physiological characterization of the representative mutants of each of the eight complementation groups are presented.

Animals↗
PubMed1979

Cytotoxic, cell agglutinating, and syncytium forming effect of purified lectins from Ricinus communis on cultured cells.

The toxicity of lectins from castor bean (Ricinus communis L.), ricin-D, ricin-E, and castor bean hemagglutinin, was investigated on five cultured cell lines. The differential effect of their constituent polypeptide chains was also investigated using these cell lines. Ricin-D, ricin-E, and castor bean hemagglutinin (CBH) possessed cytoagglutinating activity and cytotoxic activity to all five cell lines. These lectins showed the strongest toxicity to L5178Y cells, which are leukemic cells. The toxic activity of ricin-D was stronger than that of CBH in all cell lines. The constituent polypebtide chains of ricin-D and CBH were separated by DEAE-cellulose chromatography and designated as isoleucine chain and alanine chain denoted by their N-terminal amino acids. Only alanine chain of ricin-D was toxic to cells grown in vitro, whereas isoleucine chain of ricin-D and alanine chain of CBH were not toxic to the cells. Moreover, it was found that both lectins caused syncytium formation in NIH3T3 cells infected with Moloney leukemia virus and this cell fusion activity was shown to be exclusively associated with the alanine chain. Cytotoxic, cell agglutinating, and syncytium forming effect of the lectins is due to binding of the alanine chain of ricin-D to galactose-like residues of the membrane constituents of these cells.

Agglutination↗
PubMedDate not supplied

Nanometric patterning of zinc by optical near-field photochemical vapour deposition.

A new technique, optical near-field photochemical vapour deposition (NFO-PCVD) enables maskless production of nanometric structures with controllable size, chemical composition and morphology. By placing a near-field optical microscope inside the reaction chamber for photochemical vapour deposition we have deposited nanoscale metal patterns. We demonstrate for the first time, successfully deposited in the near-field region, lines of metallic zinc with the observed stripe width of 20 nm.

Journal Article↗
PubMedDate not supplied

Quantum theoretical approach to a near-field optical system.

The paper proposes a quantum theoretical formulation of an optical near-field system based on the projection-operator method. Special attention is paid to a nanometric probe tip-quantum mechanical sample system, whose interactions are essential for describing such phenomena as atom guidance and manipulation, or local excitation of a single quantum dot. The relationship to the virtual photon model--an intuitive model--is discussed, and the latter's empirical assumption of the Yukawa-type interaction between probe and sample is justified theoretically. Several applications of the theory are briefly outlined.

Journal Article↗
PubMedDate not supplied

Successful treatment with methylprednisolone pulse therapy for a life-threatening pulmonary insufficiency in a patient with chronic granulomatous disease following pulmonary invasive aspergillosis and Burkholderia cepacia infection.

A 14-year-old boy with X-linked chronic granulomatous disease developed severe invasive pulmonary aspergillosis. He was treated with itraconazole and amphotericin B. However, he deteriorated with progressive pulmonary lesions. Burkholderia cepacia was isolated from his bronchoalveolar lavage. Finally, he was given granulocyte transfusions. Following this procedure, his condition rapidly worsened leading to respiratory failure. His lung biopsy demonstrated organizing pneumonia at his right middle lobe. Then, a methylprednisolone pulse therapy was initiated together with the administration of appropriate antibiotics and adequate amounts of amphotericin B. Dramatically, his condition improved. Therefore, a methylprednisolone pulse therapy with appropriate antimicrobial drugs seems to be beneficial for severe pulmonary insufficiency in this type of patients.

Adolescent↗