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Biomedical subjects

A Takagi

Publications and source records attributed to A Takagi.

At least 325 records · Page 18Linked to original sources
PubMed1981

In situ electron microscopical observation of cells infected with herpes simplex virus.

Transport and release of herpes simplex virus (HSV) in an African green monkey kidney cell line (CV-1) was followed by electron microscopy for up to 24 h p.i. Transmission electron microscopy and scanning electron microscopy were employed. For the former approach, electron microscopical autoradiography of whole cultured cells and in situ thin section techniques were used. The following new observations were made. (1) Except in peripheral parts of the cells, where the cytoplasmic membrane could make a ruffling movement relatively freely, virus particles were found only on the dorsal surface of the cell and not on the surface facing the substratum. By observation of thin section in situ, it was confirmed that the virus particles within intracytoplasmic vacuoles were apparently released by a reverse phagocytic process from the cell surface adjacent to microvillus projections. (2) Progeny virus particles in the nucleus moved to the cell surface within 2 h after maturation.

Animals↗
PubMed1981

Production of interferon by an SV40-transformed macrophage line, BB-W-531-2.

A simian virus 40-transformed mouse macrophage line, BB-W-531-2, was examined for its ability to produce interferon. BB-W-531-2 cells showed a phenotypic change between the macrophage and the nonmacrophage states. A viral inhibitor (interferon) was produced by the cells during the phenotypic change from the nonmacrophage to the macrophage state. Cells having macrophage properties were well capable of producing interferon when they were stimulated with ultraviolet-inactivated vaccinia virus, lipopolysaccharide, a streptococcal preparation (OK-432) or polyinosinate . polycytidylate. In contrast, cells that had lost their macrophage properties did not produce interferon even when they were given the same treatments as the cells having macrophage properties. The results suggest that the ability of BB-W-531-2 cells to produce interferon is associated with the expression of several macrophage properties.

Animals↗
PubMed1981

Phenotypic change of an SV40-transformed mouse macrophage line, BB-W-531-2 induced by different cultural methods.

A simian virus 40 (SV40)-transformed macrophage clone which was established from BALB/cAnN mouse bone marrow cells was used to study the effect of different cultural conditions on the expression of macrophage properties. The macrophage clone, BB-W-531-2 line, expressed and maintained the macrophage properties, immune phagocytosis of Fc- and complement receptors, under the growth-inhibiting conditions of confluent density and of cultivation on bacteriologic dishes with reduced adhesiveness. However, the cells lost their ability to express the macrophage properties dependent upon cell density after repeated culture splits in the growing phase. These cells regained that ability when they were cocultured with cells having macrophage properties. These results suggest that there is a possible correlation between reduced multiplication and the expression of macrophage properties, and that macrophage properties which have been suppressed or blocked may be induced by diffusible factor(s) produced by macrophages.

Animals↗
PubMed1981

Studies on peptides. CII. Synthesis of a heptacosapeptide amide corresponding to the entire amino acid sequence of gastrin-releasing peptide.

The heptacosapeptide amide corresponding to the entire amino acid sequence of gastrin-releasing peptide (GRP) was synthesized by assembling seven peptide fragments followed by deprotection with a new reagent system, IM trifluoromethanesulfonic acid-thioanisole in TFA. The deprotected peptide was purified by ion-exchange chromatography on CM-cellulose followed by partition chromatography on Sephadex G-25. The latter was found to remove effectively the Met (O) derivative of GRP. The highly purified synthetic GRP was active as synthetic bombesin on the molar basis. A new carboxyl-activating reagent, thiazoline-2-thione, was employed for preparation of the necessary fragments.

Amino Acid Sequence↗