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Biomedical subjects

Y Koga

Publications and source records attributed to Y Koga.

At least 577 records · Page 32Linked to original sources
PubMed1983

Thymus-dependent increases in splenic T-cell population by indomethacin.

After administration of indomethacin, an inhibitor of prostaglandin synthesis, the number of splenic T cells increased in normal mice but not in adult-thymectomized or athymic nude mice. The enlarged T-cell population consisted mainly of Lyt-1+2+ cells. This thymus-dependent increase in T-cell population augmented in vivo antibody response to sheep erythrocytes, a T-dependent antigen. The increased T-cell population also included suppressor cells that were eliminated by treatment with anti-Lyt-2 antibody plus complement. These results suggest that increased T cells in the spleen were recruited from the thymus by an indomethacin-mediated mechanism and participated in immune responses as regulator cells.

Animals↗
PubMed1983

Enflurane induces contracture of in vitro muscle from a patient with malignant hyperthermia.

The possibility of enflurane being an inducer of malignant hyperthermia (MH) was examined by using the contracture test in in vitro muscle from a patient with MH. An administration of 2% enflurane elicited contracture in MH muscle and an elimination of enflurane relaxed this contracture. This result, therefore, strongly suggested that enflurane is the one of the trigger-agents for MH.

Enflurane↗
PubMed1983

Detectability of 201T1 cold area with myocardial phantom.

The lesion detectability of scintillation camera was studied for 201T1 imaging using simulating myocardial phantom having a cold lesion with volume of 12 cm3 (1.3 X 3 X 3). The lesion detectability expressed as level of confidence of visual evaluation on phantom images was discussed with the position of cold lesion and the object contrast defined by the maximum signal to background ratio.

Evaluation Studies as Topic↗
PubMed1983

[Antigenic structures of CEA and CEA-related normal antigens and problems related to the determination of blood CEA concentrations].

The antigenic structures of carcinoembryonic antigen (CEA) from tumor tissues, and of CEA-related antigens in normal adult feces and meconium were analyzed. Four CEA-related antigens were isolated from normal adult feces, three of them were inclusively called as normal fecal antigen (NFA) consisted of NFA-1, NFA-2 and NFCA (normal fecal cross-reacting antigen), the other was fecal NCA. NCA-2 was also isolated from meconium. CEA, NFA-2 and NCA-2 were very similar to each other physiochemically and antigenically, but CEA-distinctive and NFA-2-distinctive determinants were detected by using specifically prepared antisera. No distinctive determinant on NCA-2 was found so far tested with our anti-NCA-2 antisera. Both NFA-1 and NCA were partially cross-reactive with CEA, NFA-2 or NCA-2, but they were antigenically independent of each other. NFCA were partially cross-reactive with both NFA-2 and NCA. From these results, it was concluded that CEA and NFA-2 could be divided into four antigenic moieties, that is, NCA-common, NFCA-common, NFA-1-common determinant and CEA-distinctive or NFA-2-distinctive determinant. Among these, NFA-1-common and NFCA-common determinants seem to be dominant as judged from the reactivities with conventional anti-CEA antisera. Recently, we established a new solid-phase radioimmunoassay for CEA. It was found that the reactivity of the system with several purified CEA preparations could vary due to differences in nature, especially in the affinity to antigen, of antibody preparations used either for solid-phase or for tracer antibody. Among purified CEA preparations, some differences in reactivity with our assay system were also found. Reactivities of four CEA-assay systems, three commercially available and ours, with purified CEA and related antigen preparations were tested. It was found that the order of reaction intensity among antigen preparations varied due to assay systems, e.g. a given CEA preparation which reacted most strongly with an assay system reacted very weakly with another assay system, and vice versa. From these results, the problems concerned with variations in estimated CEA values due to assay methods were discussed.

Amino Acid Sequence↗
PubMed1983

Immunologic suppression of carcinogenesis in spontaneously hypertensive rats (SHR) with T cell depression.

A strain of spontaneously hypertensive rats (SHR) showed a selective depression of T cell functions brought about by aging. Conversely, this strain had a high NK cell activity as compared to other normal rat strains. This SHR strain was found to be much more sensitive to the carcinogenic activity of low doses of MCA than were WKA rats with normal T cell functions. Allogeneic thymus grafts almost completely restored the T cell functions of SHR, whereas injection of an immunopotentiator, NSP, enhanced NK cell activity and also caused a partial recovering of T cell functions. When immunologic restoration was achieved, generation of killer T cells to syngeneic SMT-5 tumor cells was induced and the cytotoxic activity of NK cells to K-562 cells was also enhanced. But the cytotoxic activity to the SMT-5 cells of NK cells and macrophages from the treated or untreated SHR was not detected. Allogeneic thymus grafts induced a significant transplantation resistance against a syngeneic SMT-5 tumor and injection of NSP enhanced only the survival days of the rats. Allogeneic thymus grafts also significantly suppressed the incidence of tumors induced by MCA, whereas the injection of NSP was not effective in the prevention of tumor development but was effective in prolongation of latency periods. These results support the hypothesis that immune surveillance mediated by T cells is an important mechanism for the control of tumor development.

Animals↗
PubMed1983

[Left ventricular performance during exercise in patients with constant heart rate].

In order to evaluate the response of left ventricular (LV) performance in pacemaker implanted patients (PMI pts) with constant heart rate during exercise, supine bicycle ergometer exercise was performed simultaneously in 21 PMI pts and 4 age-matched normal subjects. PMI pts were classified into two groups; Group I consisted of 16 pts with relatively good physical work capacity (maximal load: male; 80 watt or more, female; 60 watt or more), and Group II consisted of 14 pts with depressed physical work capacity (maximal load: male; 60 watt or less, female; 40 watt or less). During dynamic exercise LV end-diastolic dimension (EDD), stroke excursion (SE), percent fractional shortening (%FS) and posterior wall velocity (PWV) showed a significant increase and LV end-systolic dimension (ESD) showed a significant decrease in Group I in contrast with Group II and normal subjects. Systolic blood pressure (sBP) and sBP/ESD ratio significantly increased in Group I and normal subjects than in Group II. Furthermore, resting cardiac parameters were more impaired in Group II than Group I. Thus, it was suggested that Group I adapted to exercise according to Frank-Starling mechanism (increased EDD) and contractility due to probably increasing circulatory catecholamine (increased PWV and decreased ESD). On the other hand, Group II did not adapt sufficiently to exercise because of the limitation of preload-reserve and contractility-reserve on exercise and also at rest.

Cardiac Output↗
PubMed1983

The therapeutic effect of the antileukemia drug busulfan as an immunomodulator on transplanted fibrosarcoma KMT-17 in WKA rats.

Enhancement of specific transplantation resistance to a syngeneic tumor (KMT-17) was observed in WKA rats treated with the antileukemia drug busulfan (BU) (15 or 8 mg/kg) 5 days after immunization with X-irradiated KMT-17 cells. Similar enhancement was also produced by treatment with mitomycin C (1 mg/kg), but not cyclophosphamide (40 or 20 mg/kg), adriamycin (3 mg/kg), or BU (4 mg/kg). The therapeutic effect of BU on transplanted KMT-17 tumor in WKA rats was relatively weak, but the therapeutic efficacy of BU as an immunomodulator appeared to be almost equal to that of PS-K, lentinan, or neurotropin. By means of the tumor-neutralizing assay using spleen cells, a stronger antitumor immune response was observed in BU-treated tumor-bearing rats than in the BU-untreated control group. An improvement of the therapeutic effect was obtained by combining neurotropin with BU, although its monotherapeutic effect was insufficient.

Animals↗