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Biomedical subjects

K Orita

Publications and source records attributed to K Orita.

At least 235 records · Page 13Linked to original sources
PubMed1990

Inhibition of active oxygen generation in guinea-pig neutrophils by biscoclaurine alkaloids.

Effect of biscoclaurine alkaloids, such as cepharanthine, on active oxygen production of neutrophils was investigated. Cepharanthine inhibited both superoxide generation and luminol-dependent chemiluminescence (CL) induced by either formylmethionyl-leucyl-phenylalanine, opsonized zymosan, arachidonic acid or by phorbol myristate acetate. Ca2(+)- and phospholipid-dependent protein kinase (PKC) activity and the phosphorylation of cytoplasmic protein including 47 kDa proteins of neutrophils were also inhibited by cepharanthine; dose dependent inhibition of CL was quite similar to that of PKC. Among various biscoclaurines tested, the inhibitory effect of cepharanthine, tetrandrine and isotetrandrine was strong, but that of berbamine and cycreanine was weak; the inhibitory action of the former on lipid peroxidation and platelet aggregation were also stronger than those of the latter. These and other observations indicated that these alkaloids inhibited the active oxygen generation by way of stabilizing plasma membrane and inhibiting PKC and NADPH oxidase activation.

Alkaloids↗
PubMed1990

Antitumor effects of a new interleukin-2 slow delivery system on methylcholanthrene-induced fibrosarcoma in mice.

The interleukin-2 (IL-2) mini-pellet, the carrier material of which is a biocompatible and biodegradable atelocollagen refined from bovine skin, contains 1 x 10(6) units of IL-2 and can release IL-2 slowly in vivo by diffusion and dissolution. We have evaluated the antitumor effects of the IL-2 mini-pellet on an established solid murine tumor, methylcholanthrene-induced fibrosarcoma (Meth A). The subcutaneous administration of the IL-2 mini-pellet alone on days 8 and 11 after tumor inoculation significantly inhibited tumor growth. A significant inhibition was also seen when it was combined with the intravenous injection of 5 x 10(7) lymphokine-activated killer (LAK) cells, in comparison to the untreated controls. Moreover, therapy with the IL-2 mini-pellet alone or in combination with LAK cells also prolonged the survival of mice bearing Meth A fibrosarcoma. In order to determine the precise mechanism of action of these antitumor effects, we tested splenocytes of treated mice for cytotoxic activity in vitro and investigated tumor tissues by an immunohistochemical method. On day 2 after the administration of the IL-2 mini-pellet, the lytic activity of splenocytes against both YAC-1 and JTC-11 cells (i.e. NK and LAK activity) was significantly augmented, and on day 7 a massive accumulation of lymphocytes, which were mainly like Thy1+ and/or asialo-GM1+ LAK cells, was seen in the tumor. These findings indicate that the IL-2 mini-pellet is an appropriate system for local administration of IL-2 and can induce LAK-like effector cells at the target site.

Animals↗
PubMed1990

Extragonadal sacrococcygeal seminoma--a case report.

We report herein, a rare case of a 32 year old man who presented with a massive sacrococcygeal tumor found by digital examination. A transrectal biopsy was performed, however, as massive anal bleeding occurred 1 day later, an abdominal perineal resection was carried out. Histologic examination subsequently revealed the giant tumor to be pure seminoma. Residual masses of seminoma were detected by CT examination 1 month postoperatively and, despite irradiation, the patient died 26 months after the operation. Although there have been reports of extragonadal seminoma being located in the retroperitoneum, mediastinum and pineal body, this is the first reported case of it being found in the sacrococcygeal region.

Adult↗
PubMed1990

Antitumor effect of recombinant human interleukin-1 beta alone and in combination with natural human tumor necrosis factor-alpha.

In order to investigate the antitumor effect of recombinant human interleukin-1 beta (IL-1 beta) alone and in combination with natural human tumor necrosis factor-alpha (nHuTNF-alpha), we used female BDF1 mice bearing Lewis lung carcinoma (3LL). IL-1 beta showed an antiproliferative effect against pulmonary metastatic tumors of 3LL in a dose-dependent manner. We observed 19.6 +/- 6.6, 18.6 +/- 5.3, 14.1 +/- 4.4 and 13.0 +/- 6.0 metastatic tumors at doses of 0.5, 1.0, 2.5 and 5.0 micrograms IL-1 beta/mouse/day by daily intravenous administration (the number of metastatic tumors of the control group was 26.3 +/- 8.2). Similar results were obtained by intraperitoneal administration, but in this case, mice showed a marked decrease of body weight. When IL-1 beta was administered in combination with nHuTNF-alpha, pulmonary metastatic tumors decreased much more than when IL-1 beta was administered alone. When the control group had 18.6 +/- 12.7 metastatic tumors, the nHuTNF-alpha group had 12.3 +/- 3.9 and the IL-1 beta group had 12.8 +/- 8.0, the group which was administered both cytokines had a significantly decreased number of 5.6 +/- 3.3 metastatic tumors. This antiproliferative effect of IL-1 beta in combination with nHuTNF-alpha was reduced by the intravenous administration of anti-asialo GM1 antibody and carrageenan. The number of metastatic tumors was increased from 8.9 +/- 8.0 to 18.8 +/- 11.4 by anti-asialo GM1 antibody and from 9.5 +/- 6.8 to 28.0 +/- 12.3 by carrageenan. It was suggested that asialo GM1-positive cells and macrophage were two of the most important effectors of the antiproliferative effect of IL-1 beta and TNF-alpha.

Animals↗
PubMed1990

Differing roles of protein kinase C on the antiproliferative effects of tumor necrosis factor alpha and beta on LoVo cells.

In this study we examined whether the antiproliferative effects of tumor necrosis factor (TNF)-alpha and beta were associated with the activation of protein kinase C (PKC), using the LoVo human colon cancer cell line which is resistant to both TNFs. In combination with 12-O-tetradecanoylphorbol-13-acetate (TPA), a potent activator of PKC, TNF-alpha caused marked growth inhibition of LoVo cells, but TNF-beta had little antiproliferative effect. There was no difference in the effect when TPA was added 1 h before or 4 h after TNF-alpha administration. A PKC inhibitor, H-7, not only decreased the sensitivity of LoVo cells to TNF-alpha but also caused a slight promotion of cell proliferation and dose-dependently blocked the growth inhibition induced by TNF-alpha and TPA. These results suggested a possible regulatory function of PKC within the TNF-alpha-mediated intracellular signalling pathway. PKC may act at a later stage in the transduction pathway.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed1990

Synergistic antiproliferative effect of the combination of natural human tumor necrosis factor-alpha and natural murine interferon-alpha/beta against colon-26 adenocarcinoma hepatic metastases in a murine model.

To prevent the development of hepatic metastases after surgery for colorectal cancer, it is important to inhibit the growth of any micrometastases which occur during the operation. We used a hepatic metastasis model in mice to investigate the effects of combination therapy with natural human tumor necrosis factor-alpha (nHuTNF-alpha) and natural murine interferon-alpha/beta (nMuIFN-alpha/beta). Decreased formation of hepatic metastases by murine colon-26 carcinoma was recognized following a single injection of nHuTNF-alpha, nMuIFN-alpha/beta, or both. These inhibitory effects were synergistic. NK activity was also measured, because notaral lerller cells not only have an anti-tumor effect but are also a representative of the host immune system. Both nHuTNF-alpha and nMuIFN-alpha/beta were able to activate NK cells, and the combination of the cytokines more significantly augmented NK activity. The in vivo elevation of NK activity induced by nHuTNF-alpha, nMuIFN-alpha/beta, or their combination may be one of the mechanisms of their antiproliferative effect on experimental hepatic metastases of murine colon-26 carcinoma.

Adenocarcinoma↗
PubMed1990

Carbohydrate metabolism of rats with biliary obstruction.

Carbohydrate metabolism of rats with obstructive jaundice caused by bile duct ligation was studied by intravenous glucose tolerance test (IVGTT) and by liver perfusion. The altered levels of carbohydrate-metabolizing enzyme were examined in relation to the glucose metabolism of the cholestatic rats. In the IVGTT, the rate of fractional glucose removal was increased with increases in plasma insulin and glucagon and with a decrease in non-esterified fatty acid. In liver perfusion, neither the glucose uptake nor insulin extraction by the whole liver of icteric rats was different from the control. The increased rate of glucose removal in IVGTT may be due to enhanced glucose utilization by peripheral tissues resulting from hypersecretion of insulin. In liver perfusate supplemented with glucose, a decrease in the glucose uptake per unit liver weight was observed in relation to the lowered glucokinase activity. Formation of glycogen from glucose and of glucose from lactate was also impaired, indicating inhibition of the gluconeogenic system or relative hyperfunction of the glycolytic system, which may further contribute to the reduction in glycogen content. These metabolic disorders correlated well with the changes in activities of key carbohydrate-metabolizing enzymes, which showed a characteristic pattern consistent with the loss of differentiated hepatic functions. Uptake of glucose and its conversion to glycogen were reduced in the cholestatic liver in close association with altered activities of some of related enzymes. However, due to increased utilization by the peripheral tissues, the total amount of glucose utilized in the whole rat was not reduced.

Animals↗
PubMed1990

Effect of selected splenic irradiation on growth of meth A-fibrosarcoma in mice and partial characterization of splenic effector and suppressor cell populations.

Meth A-fibrosarcoma bearing BALB/c mice were subjected to selected splenic irradiation (2.0-4.0 Gy) on days 7 and 14 of tumor growth. Tumor growth was recorded by serial measurement. Irradiation given on day 7 caused regression of tumor, but irradiation given on day 14 did not show tumor regression. Antitumor activity in the Winn assay was detected in spleen cells 3 days after irradiation, but was not detected 7 days after. The cell surface phenotypes were analyzed on days 3, 7 and 14 of splenic irradiation using monoclonal antibodies (anti-Thy1.2 antibody, anti-Lyt1 antibody, anti-Lyt2 antibody, anti-L3T4 antibody) by flow cytometry. Thy 1.2, Lyt1, and L3T4 cells were increased on day 3 of splenic irradiation, but were not on days 7 and 14. Lyt2-cells did not show increase on days 3, 7 and 14. It was possibly suggested that selected splenic irradiation induced tumor regression was caused by the ability of irradiation to preferentially eliminate suppressor T cells, thereby allowing effector T-cells to become relatively dominant.

Animals↗
PubMed1990

Primary non-Hodgkin's lymphoma of the rectum: a case report.

A rare gastrointestinal tract neoplasm, primary non-Hodgkin's B-cell lymphoma in a 39-year-old, asymptomatic woman is described. The tumor was originally localized in the rectum without evidence of any other lymphoma-involved organ and treated by curative surgical procedure associated with postoperative chemotherapy.

Adult↗
PubMed1990

A case of necrosis of hepatocellular carcinoma and tumor thrombus in the portal vein induced by transcatheter arterial lipiodol chemoembolization.

A case of hepatocellular carcinoma is reported in which the main tumor, intrahepatic metastases and a tumor thrombus in the portal vein were necrotized completely after Lipiodol chemoembolization. In this case, the tumor thrombus seemed to act as a portal embolus. This phenomenon is interesting because Lipiodol chemoembolization alone usually can not necrotize intra- or extra-capsular invasion, intrahepatic metastasis or tumor thrombus in the portal vein. This case is considered to be suggestive of a possible therapy for hepatocellular carcinoma.

Carcinoma, Hepatocellular↗
PubMed1990

A comparison of the antitumor effects of natural human tumor necrosis factors alpha and beta: the roles of arachidonic acid metabolism and intracellular cAMP.

We compared the antiproliferative efficacies of the natural human tumor necrosis factors alpha (nHuTNF-alpha) and beta (nHuTNF-beta). A phospholipase A2 inhibitor reduced the antitumor effects of both nHuTNF-alpha and nHuTNF-beta, but the inhibitory effect was more marked for nHuTNF-alpha than for nHuTNF-beta. Two other arachidonate metabolism pathways were also examined. A cyclo-oxygenase inhibitor moderately reduced nHuTNF-alpha-induced cell growth inhibition but did not affect nHuTNF-beta-induced growth inhibition, while a lipoxygenase inhibitor slightly reduced the antitumor effects of both types of nHuTNF. A third arachidonate metabolism pathway, cytochrome P450-dependent reductase inhibitor, did not affect nHuTNF-dependent growth inhibition. Exogenous cAMP and forskolin enhanced nHuTNF-alpha-induced growth inhibition but had no effect on nHuTNF-beta-induced growth inhibition. The stimulation of cancer cells by nHuTNF-alpha resulted in a significant elevation of intracellular cAMP concentrations, whereas nHuTNF-beta caused no such elevation. Additional studies demonstrated that combined nHuTNF-alpha and nHuTNF-beta (at similar unit concentrations, so that nHuTNF-beta was present at a molar concentration 1.4-fold greater than nHuTNF-alpha) showed an antitumor activity comparable to that of nHuTNF-alpha alone. These findings suggest the antiproliferative effect of nHuTNF-alpha to be both quantitatively and qualitatively distinguishable from that of nHuTNF-beta.

Arachidonic Acid↗
PubMed1990

Assessment of Kupffer cell function in rats with chronic liver injury caused by CCl4.

Kupffer cell function was assessed by using scintigraphy to evaluate the turnover of a metabolizable tracer (99mTc-millimicrosphered albumin). The organ uptake rate of the tracer, and new parameters concerned with the degradative functions of Kupffer cells obtained from analysis of the excretion phase of the hepatic time-uptake rate curve, were measured in rats with two different types of chronic liver damage induced by carbon tetrachloride (fatty liver group and liver cirrhosis group). The hepatic uptake rate in chronic liver injury decreased, while in contrast the splenic and pulmonary uptake rates increased. A particularly high uptake by the lungs was observed. The data demonstrated a reduced phagocytic activity of the Kupffer cells in rats with chronic liver injury. The new parameters concerned with Kupffer cell degradative function; i.e. the excretion rate (K) and the degradation rate in the first 60-min (D60), were markedly decreased even in the early stage of chronic liver injury. The data showed that the impairment of Kupffer cell degradative function occurred even earlier in liver damage than impairment of the phagocytic activity, so that the K value and the D60 value were the more sensitive indicators of Kupffer cell function.

Animals↗
PubMed1989

The laser treatment of hemorrhoids: results of a study on 1816 patients.

Laser is an effective, simple and harmless clinical procedure used for the treatment of hemorrhoids, as an alternative to medical therapy or surgery. In this report, we describe our experience of applying carbon dioxide laser to hemorrhoids in a total 1816 consecutive patients. The results lead us to conclude that the laser treatment of hemorrhoids is effective in pain alleviation from the first session and that patients so treated have a much more comfortable postoperative course.

Female↗