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Biomedical subjects

M Iwata

Publications and source records attributed to M Iwata.

At least 523 records · Page 29Linked to original sources
PubMed1986

Effects of interleukin-2, OK-432 and interferon-gamma on in vitro induction of nonspecific killer cells by concanavalin A in mice.

Human interleukin-2 (IL-2), OK-432 and mouse interferon-gamma (IFN-gamma) were evaluated for their beneficial effects on in vitro induction of nonspecific killer cells by concanavalin A (Con A). Nonspecific killer cells could be induced by culturing C57BL/6 spleen cells for 4 days with Con A. Con A activated killer cells showed direct cell-mediated cytotoxicity (DCMC) and lectin-dependent cell-mediated cytotoxicity (LDCC) against natural killer (NK) sensitive YAC-1 cells, and LDCC against NK-resistant EL-4 cells in a 4 hr-51Cr release assay. Higher DCMC and LDCC reactivity against YAC-1 cells, and higher LDCC reactivity against EL-4 cells were obtained with spleen cells cultured with Con A plus IL-2, or Con A plus OK-432 than with those cultured with Con A alone. No beneficial effect of IFN-gamma and no additive effects of IL-2 plus OK-432, or IL-2 plus IFN-gamma were observed in the induction of nonspecific killer cells by Con A.

Animals↗
PubMed1986

Immunosuppression by captopril in vitro: inhibition of human natural killer activity by copper-dependent generation of hydrogen peroxide.

The effect of captopril and a mixture of captopril and copper on natural killer (NK) activity of normal human peripheral blood mononuclear cells (PBMC) was examined. Preincubation of PBMC with captopril alone did not affect their NK activity at concentrations of 5-50 micrograms/ml. However, in the presence of copper sulfate, captopril inhibited the NK activity in a dose-response fashion. Similar inhibition was observed when adherent depleted fraction was treated with captopril and copper. In the time course study, significant inhibition of NK activity by captopril and copper was already observed at 3 hr preincubation. The inhibition of NK activity by captopril and copper was completely abolished by the addition of catalase, but not by superoxide dismutase, interleukin-2, or indomethacin. Preincubation of PBMC with captopril and copper for 18 hr decreased its viability. This decrease was also reversed in the presence of catalase. These results suggest that immunosuppression by captopril in the presence of copper was mediated by hydrogen peroxide.

Captopril↗
PubMed1986

A novel macrolide antibiotic, notonesomycin A.

Fermentation of Streptomyces aminophilus subsp. notonesogenes 647-AV1 produced a mixture of antifungal antibiotics. Notonesomycin A, the main component has been characterized as a new macrolide antibiotic containing a sulfate group, a malonate moiety, two deoxysugars and a 1,3,4-trisubstituted benzene system in the molecule. It was active against some fungi and Gram-positive bacteria in vitro and effective against the sheath blight disease of rice plant in a green house test.

Animals↗
PubMed1986

[Radiation-induced differential responses of uterine adeno- and squamous cell carcinoma spheroids in dose-survival relationships].

Radiation-induced dose-survival relationships of human uterine adeno and squamous carcinoma cells grown as spheroid were studied, comparing them with monolayer cells. HEC-59 and SKG-3a cell lines were used. The spheroids were produced by Yuhas's method. In monolayer culture, D0,Dq and n values in the Hit-theory were as follows: HEC-59 (D0 = 1.6Gy, Dq = 0.6Gy, n = 1.5) and SKG-3a(D0 = 1.3Gy, Dq = 0.4Gy, n = 1.4). Survival curves of both cell lines as spheroids demonstrated biphasic curves after acute irradiation. HEC-59 cells grown as spheroids 300 microns in diameter did not have a great second component. SKG-3a cell, however, did apparently have a large amount of the second component when a 6Gy dose was exceeded. The shoulder in the dose-survival curves of both cells grown as spheroids became greater than monolayer cells up to 3Gy dose. It was therefore proven that spheroids possess similar characteristics to solid tumors. This suggests that spheroids are useful in studying radiation-induced effects in solid tumors.

Adenocarcinoma↗
PubMed1986

[Differences in the immunostimulatory activity and antitumor therapeutic effect of OK-432 and N-CWS].

Immunobiological activities of OK-432 and N-CWS were studied in BALB/c-Meth-A and C3H-MH 134 systems. Peritoneal exudate cells obtained from mice injected i.p. with OK-432 or N-CWS showed stronger in vitro cytotoxicity against Meth-A and YAC-1 cells than did those from non-treated mice. Spleen cells from OK-432 or N-CWS-treated mice exhibited lower Con A mitogenic response in comparison with those from non-treated mice. When Meth-A or MH-134 tumor cells were admixed with OK-432 or N-CWS, the intradermally inoculated tumor cells showed no or slower growth than did those admixed with saline only. There were no significant differences in all the above mentioned activities between OK-432 and N-CWS, and there was no difference in the direct tumor inhibitory activity of the two agents in vitro. However, the administration of N-CWS had no therapeutic effect against i.p.-inoculated tumor cells while OK-432 showed a strong therapeutic effect by the same treatment schedule. Further studies are required to clarify the mechanisms responsible for the difference in the therapeutic effect of the two agents.

Animals↗
PubMed1986

[A surgical case of submucosal esophageal carcinoma with esophageal leiomyoma misdiagnosed as esophageal].

A 56-year-old man with submucosal esophageal carcinoma combined with esophageal leiomyoma is presented. He had suffered from progressive dysphagia and vomiting. X-ray and endoscopic examination revealed severe stenosis of the lower esophagus with smooth mucosa, and CT scan demonstrated a circular and localized tumor. The histological diagnosis of esophageal leiomyoma was made by means of surgical biopsy. Resection of the lower esophagus and upper stomach was performed. But the postoperative pathological examination revealed submucosal esophageal squamous cell carcinoma combined with esophageal leiomyoma. The etiology and diagnosis in this case were discussed.

Carcinoma, Squamous Cell↗
PubMed1986

[Radioresistant elements in adenocarcinoma of the uterus].

Radioresistant elements in adenocarcinoma of uterine cancer were studied using SKG-3a and HEC-59 cell lines as spheroids and monolayer culture. Dose-survival curves for monolayer cultured SKG-3a and HEC-59 cells were almost similar at acute exposure. On the other hand, as spheroids grown to 300 microns in diameter, dose-survival curves for SKG-3a cells were biphasic and those for HEC-59 were monophasic. The increased shoulder in survival curves proved the contract effect of both cells. Conventionally fractionated irradiation promoted shrinkage and disintegration of spheroids as the dose was increased. All SKG-3a spheroids were destroyed over 60 Gy, but some of HEC 59 spheroids survived over 68 Gy at the total dose. The total dose at disintegration-50% was 40 Gy in SKG-3a and 48 Gy in HEC-59 spheroids. In a comparison of single with 5-fractionated irradiation, fractionation induced an increase in radioresistance of adenocarcinoma cells. The maximum recovery-dose of HEC-59 cell as spheroids was 0.4 Gy and that of SKG-3a was 0.28 Gy. The magnitude of PLD-repair in HEC-59 cells was greater than that in SKG-3a. In conclusion, the PLD-repair and contact effect could be more important factors than the hypoxic element in the acquisition of radioresistance in adenocarcinoma cells as a solid tumor under fractionated irradiation.

Adenocarcinoma↗
PubMed1985

Natural killer-like activity in human cultured lymphoid cells propagated in the presence of interleukin-2: acquired resistance to prostaglandin E2- or dexamethasone-mediated suppression.

The cytotoxic activity of human peripheral blood lymphocytes against the natural killer-sensitive target K562 was suppressed both by prostaglandin E2 and dexamethasone. On the other hand, cultured lymphoid cells propagated in the presence of interleukin-2 showed strong cytotoxic reactivity against K562 targets, and were resistant to prostaglandin E2- or dexamethasone-mediated suppression.

Cells, Cultured↗
PubMed1985

Responses to salinity and the effect of prolactin on whole animal transepithelial potential in the gobiid teleost, Gillichthys mirabilis.

Whole-animal transepithelial potential (TEP) of the goby, Gillichthys mirabilis, was measured. TEP was the same whether the electrode was implanted in the dorsal muscle or in the peritoneal cavity. TEP response to different salinities was linear from 0 to 100% seawater, and stable from 100 to 200% seawater. TEP decreased significantly in 225 and 250% seawater, and the fish became dehydrated. Plasma Na and Cl concentrations showed a linear relationship with increase in salinity from 0 to 200% seawater. In hypophysectomized Gillichthys, TEP was significantly lower than in sham-operated fish, but hypophysectomized fish with a rostral pars distalis autotransplant showed TEP similar to that of intact fish. Plasma Na and Cl in hypophysectomized fish were lower than in intact and RPD-autotransplanted fish, suggesting that prolactin is involved in maintaining normal whole-animal TEP.

Adaptation, Physiological↗
PubMed1985

Enhancement of spicule formation and calcium uptake by monoclonal antibodies to fibronectin-binding acid polysaccharide in cultured sea urchin embryonic cells.

The effect of monoclonal antibodies to fibronectin-binding acid polysaccharide (anti-FAPS) on differentiation of primary mesenchyme cells and spicule formation was examined in cultured embryonic cells isolated from the sea urchin, Hemicentrotus pulcherrimus. Spicule formation of micromere-derived cells was enhanced by anti-FAPS. The increase of spicule formation correlated with the increase of calcium uptake into micromere-derived cells and spicules. Furthermore, both spicule formation and calcium uptake were inhibited by calcium-channel blockers (verapamil, diltiazem and nicardipine) and divalent ions (manganese and cobalt). These results suggest that FAPS, a component of the blastocoelic extracellular matrix surrounding the primary mesenchyme cells, may regulate the level of calcium uptake and spicule formation.

Animals↗