Search PubMed⌕ Search

Biomedical subjects

H Kohda

Publications and source records attributed to H Kohda.

At least 109 records · Page 6Linked to original sources
PubMed1985

The active principles of the branchlet and hook of Uncaria sinensis Oliv. examined with a 5-hydroxytryptamine receptor binding assay.

Of the alkaloids obtained from Uncaria sinensis Oliv., geissoschizine methyl ether, corynantheine and dihydrocorynantheine decreased specific [3H]5-HT binding to membrane preparations from rat brain and from in-vitro experiments on guinea-pig ileum, these alkaloids were found to be partial agonists for 5-HT receptors. Therefore, they might be useful in the treatment of diseases resulting from disorders of 5-HT metabolism.

Alkaloids↗
PubMed1985

A soluble factor distinct from interleukin 2 is involved in the generation and differentiation of cytotoxic T cells.

The involvement of cytotoxic cell-generating factor (CGF) in the generation of cytotoxic cells against syngeneic tumor (T-9) cells and in the rejection of the tumor cells has been investigated. It was found that Con A-sup (culture supernatant of concanavalin A-stimulated rat spleen cells) contained CGF, which was distinct from interleukin (IL) 2 and interferon. It should be noted that spleen cells produced CGF upon inoculation of syngeneic tumor cells into tumor-sensitized rats. Production of CGF preceded the appearance of cytotoxic cells against inoculated tumor cells. In these rats, the inoculated tumor was rejected. In contrast, spleen cells failed to produce CGF upon inoculation of tumor cells into normal rats; in these rats, cytotoxic cells were not detected and the inoculated tumor grew. These data suggested that CGF was produced as an in vivo response of the host immune system and was involved in the generation of cytotoxic T cells. CGF obtained from sensitized spleen cells was chromatographically separated from IL 1, IL 2, and colony-stimulating factor, and the chromatographically separated CGF did not contain IL 3 activity.

Animals↗
PubMed1985

Establishment of rat-mouse T cell hybridomas that constitutively produce a soluble factor that is needed for the generation of cytotoxic cells: biochemical and functional characterization.

Spleen cells from Lewis rats were cultured with 4 micrograms/ml Con A. These cells were then fused with BW 5147 mouse T lymphoma cells. Two hybrid clones (6B2-B8 and 6B2-E6) obtained by fusion formed CGF effectively. It was found that hybrid cells can be boosted to produce higher levels of CGF upon stimulation with Con A. 6B2-B8 express rat T cell markers. CGF formed by 6B2-B8 had a m.w. of 23,000 and 40,000. CGF was eluted from a Mono Q anion-exchange column with an FPLC system at 0.4 to 0.6 M NaCl as a major peak and at 0.8 M NaCl as a minor peak. CGF was eluted as three peaks with pH 4.1, 4.8, and 5.2 from a Mono P chromatofocusing column. CGF from 6B2-B8 does not contain IL-1, IL-2, IL-3, or CSF.

Animals↗
PubMed1985

Extracellular matrix in hepatic granulomas of mice infected with Schistosoma mansoni. Qualitative and quantitative analysis.

To investigate the role of extracellular matrix molecules in the granulomatous inflammation, cercariae of Schistosoma mansoni were injected subcutaneously into BALB/c mice. Well-organized granulomas consisting mainly of stimulated macrophages and epithelioid cells developed in the liver at 11 weeks after infection, thereafter showing a tendency to heal. Fibronectin and heparan sulfate proteoglycan deposition appeared around parasite eggs, then increased distinctly at 11 weeks after infection, and subsequently diminished. Quantities of glycosaminoglycans and hydroxyproline in the egg lesion increased significantly at 11 weeks after infection. Thereafter, the amounts of glycosaminoglycans decreased, whereas hydroxyproline content did not. The data suggest that fibronectin and other macromolecules interact to form granuloma extracellular matrix, and that these extracellular events participate in the development of granulomatous inflammation and subsequent fibrosis induced by schistosome eggs.

Animals↗
PubMed1985

Functional analysis of mononuclear cells infiltrating into tumors. II. Differential ability of mononuclear cells obtained from various tissues to produce helper factors that are involved in the generation of cytotoxic cells.

The requirement of CGF in the generation of cytotoxic cells against syngeneic tumor cells (T-9) and in the rejection of transplanted T-9 cells has been investigated. Spleen cells obtained from sensitized rats showed strong cytotoxicity against 51Cr-labeled T-9 cells upon incubation with CGF for 48 hr. Human recombinant IL 2 and rat IFN failed to generate cytotoxic cells from spleen cells of sensitized rats. CGF are produced by spleen cells upon inoculation of T-9 cells into sensitized rats as a host in vivo immune response. Production of CGF preceded the appearance of cytotoxic cells in regional lymph node and tumor tissues. In those rats, inoculated tumor cells were eventually rejected. In contrast, spleen cells failed to produce CGF upon inoculation of T-9 cells in unsensitized rats. Cytotoxic cells were not detected in unsensitized rats, and inoculated tumor grew in those rats. Thus, CGF is likely to be involved in the generation of cytotoxic cells and in the rejection of inoculated syngeneic tumor cells. A Mono Q anion-exchange column with an FPLC system allowed the chromatographic separation of CGF from IL 1, IL 2, IL 3, and CSF.

Animals↗
PubMed1983

Characterization of glycoproteins isolated from porcine zonae pellucidae.

Two glycoproteins, tentatively designated as PZ-alpha and PZ-beta, have been isolated and purified to homogeneity from porcine zonae pellucidae by a simple purification procedure producing a high yield. The procedure included the dissolution of the zona material in 0.1 M sodium borate buffer pH 10.0, Sephadex G-100 column chromatography and preparative SDS-polyacrylamide gel electrophoresis. The purified glycoproteins gave a single band on polyacrylamide gel and had molecular weights of 60 000 (PZ-alpha) and 96 000 (PZ-beta). Glutamic acid was detected as the NH2-terminal residue in both glycoproteins, using the dansyl chloride method. Though their amino acid compositions were similar, their carbohydrate contents were slightly different (PZ-alpha: 24.9%; PZ-beta; 19.6%), but these components contained the same types of monosaccharides: fucose, mannose, galactose, NAcGlc and sialic acid. The antigenic properties of the two glycoproteins were indistinguishable by immunodiffusion tests. The PZ-beta could be converted in part to smaller molecular weight components, though not to PZ-alpha, by treatment with beta-mercaptoethanol. Thus clear differences between PZ-alpha and PZ-beta could not be detected by chemical or immunological analyses except for the difference in the behaviour on SDS-polyacrylamide gel electrophoresis.

Amino Acids↗
PubMed1983

Meiosis-inhibiting effects in vivo of antiserum to progesterone on follicular ova in immature rats treated with gonadotropins.

Effects of the neutralization of endogenous progesterone with rabbit antiserum to progesterone (anti-progesterone) on germinal vesicle breakdown of ova in follicles of small (less than 125 micrometers), intermediate (125-250 micrometers) and large (greater than 250 micrometers) diameter were examined by a quantitative histological technique. Immature rats were treated with 5 IU pregnant mare's serum gonadotropin (PMS) then with 10 IU human chorionic gonadotropin (hCG). Administration of anti-progesterone together with hCG 6 h later significantly decreased the incidence of germinal vesicle breakdown of ova in the large follicles, but not in the intermediate ones. This treatment did not affect the proportion of intermediate to large follicles in the population. Replacement with progesterone 1 h after the simultaneous injection of hCG and anti-progesterone partly reversed the reduced incidence of meiosis. An injection of rabbit antiserum to estrone, in addition to the replacement with progesterone 1 h after the simultaneous injections of hCG and anti-progesterone, restored the incidence of meiosis to a value comparable to the values found for control rats treated sequentially with PMS and hCG. We concluded that the hCG-induced preovulatory rise in progesterone has a limited but definite stimulatory effect on the resumption of meiosis in the ova of large follicles and that it mediates the meiosis-inducing action of hCG.

Animals↗
PubMed1983

Co-operation of progesterone and prostaglandins in ovulation induced by human chorionic gonadotrophin in immature rats primed with pregnant mare serum gonadotrophin.

Serial injections of a mixture of prostaglandin (PG) E2 and F2 alpha 0, 2, 4, and 6 h after simultaneous injection of human chorionic gonadotrophin (hCG) and indomethacin incompletely restored the ovulation that would have been blocked by indomethacin in immature rats treated with pregnant mare serum gonadotrophin followed by hCG. Serial injections of another mixture of PGE2 and PGF2 alpha 6, 8, 10 and 12 h after simultaneous injection of hCG and indomethacin similarly reversed, in part, the inhibitory effects of indomethacin on hCG-induced ovulation. In contrast, serial injections of the mixtures of PGE2 and PGF2 alpha 0, 2, 4, 6, 8, 10 and 12 h after simultaneous injection of hCG and indomethacin completely restored the indomethacin-blocked ovulation, suggesting that the prostaglandins mediate the action of hCG on ovulation both in the earlier and later stages of the preovulatory process. Six hours after simultaneous injection of hCG and indomethacin serial injections of a mixture of PGE2 and PGF2 alpha reproduced the acute and temporary increase in concentrations of progesterone and testosterone in plasma which would have been abolished by indomethacin. Progesterone given concurrently with hCG and indomethacin partially antagonized the inhibitory action of indomethacin on ovulation. Serial injections of a mixture of PGE2 and PGF2 alpha 6, 8, 10 and 12 h after concurrent administration of progesterone with hCG and indomethacin completely restored the indomethacin-blocked ovulation, suggesting that progesterone can substitute the action of prostaglandins injected serially in the first half of the preovulatory process. It was concluded that the co-operation of progesterone in the earlier stage and of prostaglandins in the later stage of the preovulatory interval is required to mediate the action of hCG on ovulation.

Animals↗
PubMed1982

[A progesterone-dependent step in HCG-induced ovulation in immature rats (author's transl)].

The effect of antiserum to progesterone on follicular rupture during the ovulatory process was studied. Mean number of ova shed following treatment of immature rats sequentially with PMS and hCG was reduced in a dose-dependent manner by simultaneous injection with increasing doses of antiserum to progesterone. When the animal received 1.2 ml of the antiserum, hCG-induced ovulation was blocked completely. To be effective, antiserum treatment had to be within 6 h of hCG treatment; antiserum given 9 h after hCG was ineffective. Progesterone restored' the antiserum blocked ovulation completely or incompletely when administered intravenously within 6 h of treatment with hCG. The first 6 h was shown to be a progesterone-dependent step in the ovulatory process in this experimental system.

Animals↗
PubMed1981

Use of chromogenic substrate S-2251 for determination of plasminogen activator in rat ovaries.

A simple specific and reproducible method for determination of plasminogen activator activity in rat ovaries has been developed by using the chromogenic substrate S-2251. The two steps of enzymatic reactions, i.e. activation of plasminogen and subsequent hydrolysis of the substrate was performed in one step incubation. A linear relationship was observed between the amount of chromogen produced and activator activity in the range of the optical density form 0.05 to 1.20 for 30 min's incubation. Endogenous activity of non-specific proteases, plasmin or plasmin inhibitors which might be contained in rat ovaries turned out not to interfere with the specificity of a standardized assay procedure. Reproducibility was firmly established with coefficient of variation not exceeding 10%. Using this method, a marked increase followed by a drastic decrease in the activator activity was shown with rat ovaries around the time of ovulation after the injection of human chorionic gonadotropin.

Animals↗
PubMed1981

A new method for preparation of pure zonae pellucidae in large quantities from porcine ovaries.

A new method for preparation of large quantities of zona substance in pure form from porcine ovaries has been described. In addition to the previously reported techniques of glass wool treatment and sieving by saran meshes, the following three significant improvements have been introduced: disruption of ovaries by an electric machine equipped with two multi-needed disks, which resulted in a considerably accelerated recovery of follicular oocytes with a high yield; low-speed centrifugation at 170 X g for 15 s was found to be an obligatory step to eliminate light particulate material from the crude oocyte suspension; use of 50% sucrose solution in discontinuous density gradient centrifugation permitted complete separation of homogeneous samples at two stages of the final preparation of zona-encased oocytes or of oocyte-free zonae. Microscopic examination revealed no contaminating components in the zona preparation. With this method 93 mg of lyophilized zona preparation were obtained from 24 553 porcine ovaries. Analysis of a solubilized zona substance by Sephacryl S-200 column chromatography showed the presence of two major glycoproteins which could not be separated completely from each other. By analysis of the two components with SDS-PAGE, only a single, but broad, band of glycoprotein was found, indicating the successful isolation of a major component(s) from porcine zonae.

Animals↗