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Biomedical subjects

T Kameda

Publications and source records attributed to T Kameda.

At least 109 records · Page 6Linked to original sources
PubMed1989

Impaired susceptibility of human trophoblast to MHC nonrestricted killer cells: implication in the maternal-fetal relationship.

Mammalian pregnancy has frequently been termed "Nature's allograft," and there is developing evidence that the placental trophoblast cells in their key position at the maternal fetal interface are responsible for escape mechanisms to the maternal immune system. In this paper, we show impaired susceptibility of human trophoblastic tumor cells to major histocompatibility complex (MHC) nonrestricted cytotoxicity systems such as natural killer (NK) cells and lymphokine-activated killer (LAK) cells. LAK cells were induced by the culture of peripheral blood mononuclear lymphocytes (PBL) in recombinant interleukin-2 (rIL-2). Among 21 cultured cell lines derived from various tissues and organs tested, five choriocarcinoma-derived cell lines gave decreased levels of LAK lysis. Cold-target inhibition study and trinitrophenyl (TNP) modification experiment clearly indicated that the impaired sensitivity of trophoblast cells to LAK lysis is due to the decrease of a common target molecule recognized by LAK effector cells. It is suggested that the impaired susceptibilty of trophoblast to MHC nonrestricted killer cells should be functional for the survival of the semiallogeneic fetus.

Cytotoxicity, Immunologic↗
PubMed1989

Trophoblast-derived immunoregulatory factor: demonstration of the biological function and the physicochemical characteristics of the factor derived from choriocarcinoma cell lines.

An immunosuppressive factor released by choriocarcinoma cell lines was analyzed in the present study. It inhibited the proliferative responses of human T cells stimulated by lectins or alloantigens. It also blocked the generation of alloreactive cytotoxic T cells. The suppressive activity of the factor was detected in the responses of the T cells costimulated with 1 nM 12-O-tetradecanoyl phorbol 13-acetate and 1 microM A23187, suggesting the possibility that the factor acted on the intracellular signal transduction in T cells rather than interfering with early events such as T cell receptor signal transduction through cell membranes. Moreover, the factor acted directly on T cell proliferation pathways without activation of suppressor cells but did not act on T cell activation pathways. Taken together, all these findings expanded our previous reports on a factor released by normal trophoblasts, indicating the possible identity of the two factors. The physicochemical properties of the choriocarcinoma-derived factor were examined, and the biological significance of the factor during pregnancy was discussed in this paper.

Calcimycin↗
PubMed1989

Familial aortic dissection: a report of rare family cluster.

Acute aortic dissection occurred in three of four siblings without Marfan syndrome. All of them were successfully treated by operation and remain well 6-42 months after operation. Their mother died suddenly in another hospital of acute aortic dissection. All her siblings were dead and cardiovascular disease was suspected in all of them.

Acute Disease↗
PubMed1989

[Low sensitivity of choriocarcinoma cell lines to tumor necrosis factor (TNF)-alpha].

Sensitivity of cultured choriocarcinoma cell lines to tumor necrosis factor (TNF)-alpha and interferon (IFN)-gamma was examined and compared with that of other cultured tumor cell lines. Tumor cells were cultured with 1,000 mu/ml of TNF-alpha and/or 100 mu/ml of IFN-gamma for 24hr. Antitumor effects of the lymphokines were measured by 3H-thymidine uptake and tetrazolium salt (MTT) colorimetric assay. The results revealed that TNF-alpha and/or IFN-gamma had little anti-tumor effect on the choriocarcinoma cell lines tested, while they had cytostatic and cytotoxic effects on other cultured tumor cell lines including Panc-1 (pancreatic carcinoma cell line), Lovo (colon carcinoma cell line) and Ishikawa (uterine endometrial carcinoma cell line). We also examined the effect of TNF-alpha and IFN-gamma on the expression of major histocompatibility complex (MHC) class I antigens in these tumor cell lines by means of cellular binding radioimmunoassay. No enhancing effect was observed on choriocarcinoma cell lines after the treatment with TNF-alpha and/or IFN-gamma. These results suggested the existence of a unique property of choriocarcinoma cells which results in the resistance to host immune attacks.

Choriocarcinoma↗
PubMed1989

Cytogenetical analysis of the human gastric carcinoma cell line TMK-1.

We examined a human gastric carcinoma cell line TMK-1 cytogenetically by G-banding technique. TMK-1 cells were characterized not only by numerical aberrations but also by structural rearrangements affecting various chromosomes. The modal chromosome number was found to be in the hypotriploid range with most ranging between 64 and 66. Flow cytometry revealed near triploid DNA histogram which was correlated well with chromosome counts. Gain of chromosome 7, 9, 11, and X was found in all of the 25 cells examined and trisomy of chromosome 3, 5, 10, 19, 21 and 22 was also frequently detected. Loss of Y chromosome was shown in all of the cells and monosomy of chromosome 6 and 13 was frequently detected. The most conspicuous rearrangements involved chromosome 6, 12, and 16 which showed complex nonreciprocal translocation. Twenty-two cells (88%) had isochromosome of 12q. A brief review is made of reported karyotype of human gastric cancers.

Adenocarcinoma↗
PubMed1989

The effect of phorbol esters on cell growth and epidermal growth factor receptor modulation in a human gastric carcinoma cell line TMK-1.

Tumor promoting phorbol esters, 12-O-tetradecanoylphorbol-13-acetate (TPA) and phorbol-12,13-dibutyrate (PDBu), significantly enhanced the growth of human gastric cancer cell line TMK-1, whilst activating protein kinase C. The time course of 125I-epidermal growth factor (EGF) binding to TMK-1 cells after TPA treatment showed a decrease in the number of EGF receptors on TMK-1 cells within 3 hr. Autophosphorylation of EGF receptor decreased in accordance with the decrease of EGF binding by TPA treatment. Scatchard plot analysis of TMK-1 cells after TPA treatment showed that high affinity EGF receptor disappeared at 3hr but the number of EGF receptors increased at 24 hr. These findings suggest that tumor promoting phorbol esters stimulate the cell growth through activation of protein kinase C and modification of EGF receptor of human gastric cancer cell line TMK-1.

Cell Division↗
PubMed1989

[Low susceptibility of choriocarcinoma cell lines to lymphokine activated killer (LAK) cells].

We investigated the anti-tumor effect of lymphokine activated killer (LAK) cells on various carcinoma cell lines as it may play an important role in the immunotherapy of gynecologic cancers. Peripheral blood lymphocytes (PBL) were cultured in 10 U/ml of recombinant interleukin-2 (rIL-2). The cytotoxic action of LAK and natural killer (NK) on carcinoma cell lines was measured by a standard 4-hr 51Cr-releasing assay. Daudi and RPMI 1788, NK resistant B cell lines were lysed by rIL-2 activated PBL although they were not killed by human fresh PBL. LAK cells thus induced were markedly cytotoxic to sixteen carcinoma cell lines. However, five choriocarcinoma cell lines were resistant to LAK action because specific action was less than 30% at effector/target ratio of 20. The cold target competitive inhibition experiments showed that the choriocarcinoma cell line GCH-1 induced much lower inhibition than Daudi cells. These results indicate that the low susceptibility of the choriocarcinoma cell lines to LAK cells could be due to the lack of the effector molecules recognized by killer cells.

Cell Line↗
PubMed1988

Expression of epidermal growth factor receptor in human gastric and colonic carcinomas.

The expression of epidermal growth factor (EGF) receptor was examined immunohistochemically in a total of 122 gastric and 61 colonic carcinomas, out of which 16 gastric and 8 colonic carcinomas were also examined by 125I-labeled EGF binding analysis and Western blotting. The values of EGF binding were 12.68 +/- 1.98 (SE; n = 16) fmol/mg protein in gastric carcinomas and 5.72 +/- 2.15 (n = 8) fmol/mg protein in nonneoplastic gastric mucosa, the difference being significant (P less than 0.01). In the colonic tissue, the binding capacities in carcinomas and nonneoplastic mucosa were 13.29 +/- 4.17 (n = 8) and 10.68 +/- 0.41 (n = 3) fmol/mg protein, respectively. Scatchard analysis of 125I-labeled EGF binding indicated a single class of receptors in gastric and colonic carcinomas with an apparent Kd value of from 111 to 277 (n = 4) and from 87.4 to 341 fM (n = 5), respectively, except for one gastric carcinoma having two classes of receptors (Kd = 15.9 and 896 fM). In Western blotting using monoclonal anti-EGF receptor antibody, various levels of EGF receptor expression were detected in 12 (85.7%) of the 14 gastric carcinomas and in 7 (87.5%) of the 8 colonic carcinomas. Immunohistochemically, EGF receptor immunoreactivity was detected in one (3.8%) of the 26 early gastric carcinomas, while it was observed in 33 (34.4%) of the 96 advanced gastric carcinomas, the incidence between the two being significantly different (P less than 0.01). In the colonic carcinomas, 47 (77.1%) of the 61 cases showed positive immunoreactivity to EGF receptor, which did not differ by histological type.

Carcinoma↗
PubMed1988

Significance of early angiographic follow-up after internal thoracic artery anastomosis in coronary surgery.

The authors report about the radiological checking of the patency of the internal thoracic artery transplant in 75 patients with coronary artery disease, using intraarterial DSA in the early postoperative phase (between 6th and 8th postoperative day). The left or the right brachial artery was punctated and the contrast medium was injected at a dosage of 50 ml in counter-current. Only one angiogram series per patient was necessary to appraise the anastomosis and the perfusion of the bypass applied. In 5 patients a stenosis and in 4 patients an occlusion of the transplant could to be diagnosed. Early postoperative angiography enables quality control. In case of occlusion reoperation may be indicated.

Adult↗