Search PubMed⌕ Search

Biomedical subjects

T Okabe

Publications and source records attributed to T Okabe.

At least 487 records · Page 27Linked to original sources
PubMed1982

Effects of salmonella infection on hemopoietic stem cells in mice.

Effects of induced salmonella infection on hemopoietic stem cells were studied by comparing hemopoietic response of mice to killed and viable bacteria of an attenuated strain of Salmonella enteritidis. Results are as follows: i) A single injection with viable bacteria induced an increase in pluripotent stem cells (CFUc) and granulocyte-macrophage progenitor cells (CFUs) in the spleen and a decrease in these cells in the bone marrow, ii) A single injection or repeated injections of killed bacteria resulted in an increase of CFUs and CFUs in the bone marrow as well as in the spleen, iii) Histological examination revealed no inflammatory change that might account for the different hemopoietic responses seen with the viable and killed bacteria. Our results suggest that the hemopoietic responses in salmonella-infected mice reflect not only the influence of LPS but also effects of viable intracellular bacteria on the reticuloendothelial system constituting the hemopoietic microenvironment.

Animals↗
PubMed1982

Effects of Salmonella infection on hemopoietic stem cells in mice immunized with Salmonella vaccines.

Effects of Salmonella enteritidis infection on hemopoietic stem cells were examined in mice immunized with killed bacteria and in those immunized with viable bacteria. The results are summarized as follows: i) Mice immunized with the killed salmonellae showed hemopoietic responses similar to those of normal, nonimmunized mice, i. e., increase in CFUs and CFUc in the spleen and decrease in these cells in the bone marrow. ii) Mice immunized with viable salmonellae were protected from such decreases in bone marrow stem cells, but showed a decrease in spleen CFUc, with a concomitant decrease in the peripheral granulocytes. iii) Hemopoietic responses to viable salmonellae of mice immunized with viable bacteria differed from the responses to killed salmonellae of normal, non-immunized mice. These results suggest that both LPS and cell-mediated immune responses affect hemopoietic stem cells in mice infected with salmonellae.

Animals↗
PubMed1981

Characterization of effector cells responsible for cell-mediated cytotoxicity in patients with carcinoma of the prostate.

In earlier experiments it has been shown that cellular cytotoxicity of patients with prostatic carcinoma (CaP) as measured by cytolysis of EB 33 target cells correlates with the extent of their tumor lesion: a high grade of cytotoxicity was observed only when CaP was confined to gland. In order to define a possible in vivo immunological host-tumor interaction, further characterization of the type of effector cell responsible for in vitro killing has been attempted. Effector cells could be either tumor-specific sensitized T cells, K cells, macrophages or NK cells. Antibody-dependent K-cell activity could most likely be excluded, since autologous and homologous serum did not affect the extent of EB 33 killing when added to the test medium. Further separation of effector cells by nylon wool columns resulted in increased cytolysis of EB 33 target cells. This can be due either to tumor-specific T-cell-mediated mechanisms or to an increased natural killer cell activity, as macrophages and B cells were significantly removed by this measure. Separation of T and NK cells is necessary to ascertain the effector cell responsible for the in vitro killing of tumor cells derived from human CaP.

Adult↗
PubMed1981

Cells originating from sarcoid granulomas in vitro.

In an attempt to obtain in vitro experimental models for sarcoidosis, the primary cultures of granuloma cells were initiated with lymph nodes from 10 sarcoidosis patients. The cells migrating from tissue explants became confluent at 2 wk of culture. These cells exhibited overall morphologic features and enzymatic activities resembling those of in vivo granuloma epithelioid cells. By light and electron microscopy, the epithelioid cell in vitro contained a clear, large nucleus with 1 or 2 prominent nucleoli. The cytoplasm was characterized by the occurrence of lysosomal dense bodies and electron-lucent vacuoles, besides many mitochondria and well-developed Golgi complexes. The cell surface exhibited many processes, mainly lamellipodia. Large amounts of angiotensin converting enzyme activity (3.9 to 50.1 nmol/min/ml) lysozyme activity (3.9 to 23.0 micrograms/ml) were demonstrated in the medium used for culture. The results indicated that the major cell population grown in these cultures is derived from the epithelioid cells in sarcoid granulomas.

Adult↗
PubMed1981

Basic peptide with insulin-like activity in human serum.

A peptide with insulin-like activity was isolated from human plasma. In the purification, insulin-like activity (ILA) was monitored by radioreceptor assay for insulin, using human placental membrane and [125I]-insulin. ILA was extracted from Cohn fraction III with acid-ethanol and chromatographed on Sephadex G-75 in 1% formic acid. When the active fractions were subjected to ion-exchange chromatography with CM-cellulose, the ILA was adsorbed to the column at pH 5.0 and was eluted with a gradient of ammonium acetate. The chromatographic behavior of the ILA was not identical to that of somatomedin A as determined by radioreceptor assay (RRA) for the latter. On isoelectric focusing of the ILA from the CM-cellulose column, insulin-like activity was distributed over a wide pH range. The ILA that was focused at pH 7.5-9.0 was further purified by gel filtration on Sephadex G-50 in 1 M acetic acid. The specific activity of the basic ILA was approximately 200 mU insulin equivalent /mg protein. The apparent molecular weight of the material was estimated to be 7,000. It stimulated [14C]-glucose oxidation in rat epididymal fat cells and had sulfation activity in chick chondrocytes. Furthermore, the basic ILA had a potent mitogenic activity in Balb/c-3T3 cells. Thus, the basic ILA is qualified as an 'insulin-like growth factor' (IGF). It is obviously different from somatomedin A, and may be closely related to IGF-I or somatomedin C. Subsequently, RRA for the basic ILA was developed in serum concentration of the basic ILA were determined. The serum concentrations of the basic ILA were high in acromegalics and low in patients with hypopituitarism. Thus, the basic ILA is entitled to be one of the IGFs.

Chromatography, Gel↗