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Biomedical subjects

K Tanabe

Publications and source records attributed to K Tanabe.

At least 487 records · Page 27Linked to original sources
PubMed1987

Secretion by Toxoplasma gondii of an antigen that appears to become associated with the parasitophorous vacuole membrane upon invasion of the host cell.

Monoclonal antibodies against Toxoplasma gondii were prepared to characterize antigens of the parasite. Immunoperoxidase staining of parasites fixed with paraformaldehyde and glutaraldehyde (PFAGA) followed by Triton X-100 treatment showed that the antibody of clone I-63 recognized an antigen located in the anterior part of the parasite. When analysed by SDS-PAGE and immunoblotting, the antigen migrated in a 66 x 10(3) Mr region. The parasite antigen diminished greatly in parasites after invasion of host cells, but reappeared around a time when intracellular T. gondii multiplied. Immunodetection on PFAGA-fixed T. gondii-infected cells, whose membranes were permeabilized by freeze-thawing in the presence of 5% glycerol, demonstrated that, immediately after parasite invasion, the I-63 antibody-reactive antigen appeared to become associated with the parasitophorous vacuole (PV) membrane, that had been formed mainly by invagination of the host-cell plasma membrane so as to surround an invading parasite. The antigen remained associated with the PV membrane for some time, but disappeared later when the PV increased in size after the parasites had multiplied several times. These results were strengthened by immunoelectron microscopic observations: the antigen that had been localized at the anterior part of the parasite before invasion appeared in an area of the host cell cytoplasm around the tips of penetrating parasites and, thereafter, extended throughout the surface of the PV membrane when parasites completed invasion. Thus, it appears that the I-63-reactive antigen is secreted by T. gondii upon invasion of the host cell and becomes associated with the PV membrane shortly after invasion.

Animals↗
PubMed1987

Biopharmaceutical characteristics of a suppository base containing poly (oxyethylene)-poly (oxypropylene) copolymer, Unilube. I. Effects of a suppository base containing Unilube 70DP-950B on release and rectal absorption of aminopyrine in rabbit.

The rectal absorption of aminopyrine (AP) from a three-component-system suppository base (TCS), which is a mixture of oleaginous base, water-soluble base and the poly-(oxyethylene) poly-(oxypropylene) block copolymer, Unilube, was investigated. Albino rabbits were used as the animal model. The bioavailability of oleaginous base and water-soluble base (polyethylene glycol 4000) were 44.3% and 82.6%, respectively. The time to reach maximum plasma concentration (Tmax) of the oleaginous and the water-soluble bases were 21.0 +/- 8.2 min and 33.0 +/- 16.4 min, respectively. When TCS was used, its Tmax was 30 min and increasing the amount of Unilube in the base from 5% (w/w) to 20% (w/w) decreased the bioavailability from 100.4% to 47.2%. The softening temperature of TCS was 55-57 degrees C. Collectively, TCS containing 5% of Unilube gave significantly higher bioavailability than the other bases without softening until 57 degrees C. Also, the results of the two different release tests were compared with the results of an animal experiment in this paper.

Animals↗
PubMed1986

An increase in water content of mouse erythrocytes infected with Plasmodium yoelii.

Mean cell volume and mean cell water content were examined in Plasmodium yoelii-infected mouse erythrocytes by gas chromatography and 3H-sucrose. Mean cell volume increased by 16% in infected erythrocytes with late trophozoites and schizonts. Mean cell water content further increased by 23% in the infected erythrocytes. Measurement of the erythrocyte potassium and sodium concentrations by an atomic absorption spectrophotometer revealed that the infected erythrocytes contained highly elevated sodium and slightly reduced potassium levels when calculated per single erythrocyte. It is suggested that membrane transport processes of sodium and potassium are changed in P. yoelii-infected erythrocytes and that a passive inflow of sodium takes place, which results in an increase in intra-erythrocytic water content.

Animals↗
PubMed1986

Mutagenicity of the photochemical reaction products of pyrene with nitrogen dioxide.

The mutagenicity of the photochemical reaction products of pyrene with nitrogen dioxide (NO2) and the mutagens in them were investigated for the interpretation of their biological significance as genetoxic hazards of polycyclic aromatic hydrocarbons (PAHs) in airborne particles. Samples extracted from the photochemical reaction products of pyrene with NO2 diluted with air using a high-pressure mercury lamp were mutagenic for Salmonella typhimurium strains TA97 and TA98 in the absence of S9 mix, with a trend to detoxification in the presence of the metabolic system. The mutagens in the crude samples extracted from their products, which were fractionated by normal-phase high-performance liquid chromatography (HPLC) on a column of Nucleosil 100-30 with n-hexane-benzene as an eluting solution, were analyzed by HPLC, mass spectrometry and Fourier transform infrared (FT-IR) spectrometry. Based on these results, it was recognized that 1-nitropyrene (1-NP), 1,3-dinitropyrene (1,3-DNP), 1,6-dinitropyrene (1,6-DNP) and 1,8-dinitropyrene (1,8-DNP) was formed by the photochemical reaction of pyrene with NO2. The yield of DNPs peaked at 2-3 h irradiation.

Chromatography, High Pressure Liquid↗