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Biomedical subjects

S Todo

Publications and source records attributed to S Todo.

At least 541 records · Page 30Linked to original sources
PubMed1988

Effect of 15-deoxyspergualin on experimental organ transplantation.

DSPG had a definite but relatively feeble immunosuppressive effect in rats undergoing heterotopic heart transplantation and in dogs after renal transplantation. The drug was toxic in both species, although less so in rats. In dogs, synergistic interactions with cyclosporine and steroids were not evident.

Animals↗
PubMed1988

Amelioration of normothermic canine liver ischemia with prostacyclin.

A model of hepatic ischemia was developed in dogs using a pump-driven splanchnic-to-jugular vein bypass during crossclamping of the portal triad. An LD50 was established with three hours of ischemia. PGI2 given for one hour before the ischemic insult ameliorated the ischemic injury and increased survival.

Animals↗
PubMed1987

Platelet aggregating activity mediated by thrombin generation in the NCG human neuroblastoma cell line.

Platelet aggregating activity of the NCG human neuroblastoma cell line was compared with that of the HL-60 human promyelocytic leukemia cell line. NCG, in intact cell suspensions and ultracentrifuged pellets, induced platelet aggregation most significantly in heparinized platelet rich plasma (PRP) containing 2.5 units/ml of heparin, but not in the presence of higher concentrations of heparin or 5 mM ethylenediamine-tetraacetate or in citrated PRP. NCG induced platelet aggregation was also inhibited by hirudin or (2R,4R)-4-methyl-1-[N2-(3-methyl-1,2,3,4-tetrahydro-8-quinolinesulfon yl)-L- arginyl]-2-piperidinecarboxylic acid (MD 805) in the same manner as that of tissue thromboplastin induced platelet aggregation. HL-60 cells did not induce platelet aggregation in our heparinized PRP assay systems; however, after treatment with neuraminidase HL-60 cells became active in aggregating platelets in either heparinized or citrated PRP. NCG demonstrated high procoagulant activity by either intact cell suspensions or ultracentrifuged pellets. The procoagulant activity of NCG was reduced in Factor VII deficient human plasma as it was in the results obtained by tissue thromboplastin. These results suggest that NCG induces platelet aggregation via thrombin generated through procoagulant activity which is shed in association with microvesicles demonstrated in the ultracentrifuged pellets. This type of platelet aggregating activity found in NCG is significantly different from that of HL-60.

Adenosine Diphosphate↗
PubMed1987

131I-meta-iodobenzylguanidine scintigraphy in patients with neuroblastoma.

Twenty-six studies by meta-(131I)-iodobenzylguanidine scintigraphy (131I-MIBG), 26 studies by 67Ga-citrate and 33 99mTc-hydorxymethylene diphosphate (99mTc-HMDP) scintigraphic studies were performed for 10 patients with abdominal neuroblastoma. Comparing the 131I-MIBG images obtained at 24, 48 and 72 h, the 48-h image was the most distinctive for the tumor. Intrabdominal primary lesions, which ranged from bean to fist-size, were visualized in 7/7 cases (100%) by 131I-MIBG, 4/7 cases (57%) by 67Ga-citrate and 4/8 cases (50%) by 99mTc-HMDP before surgery and at diagnosis. In serial follow-up of these patients after starting chemotherapy, 131I-MIGB detected 100% of regressing primary tumors. Studies of 5 postoperative patients showed negative images for the primary tumor in all 3 scintigraphies except one in whom 131I-MIBG was positive, but not 67Ga-citrate or 99mTc-HMDP, for an unresectable residual tumor. 131I-MIBG also detected metastatic lesions not predicted by 67Ga-citrate or 99mTc-HMDP and reflected tumor progression more sensitively than known tumor markers such as urinary vanillylmandelic acid (VMA), homovanillic acid (HVA), serum neuron-specific enolase (NSE) and ferritin. These findings indicate that the 48 hr 131I-MIBG scintigraphy is superior to 67Ga-citrate or 99mTc-HMDP images and to other biochemical markers in monitoring the effect of treatment on neuroblastoma.

3-Iodobenzylguanidine↗
PubMed1987

Different response to epidermal growth factor of hepatocytes in cultures isolated from male or female rat liver. Inhibitor effect of estrogen on binding and mitogenic effect of epidermal growth factor.

Deoxyribonucleic acid (DNA) synthesis in hepatocytes isolated from the livers of male and female rats has been compared in monolayer culture. Plating efficiency, DNA and protein content, viability, and morphologic appearance were the same in cultures prepared with hepatocytes isolated from male or female rats. Epidermal growth factor (EGF)-induced DNA synthesis was significantly higher in hepatocytes from male rats than in hepatocytes from female rats. This was the case whether hepatocytes were isolated from normal or partially hepatectomized male or female rats. Hepatocytes isolated from regenerating liver synthesize more DNA than those isolated from normal liver in response to EGF. This increased response to EGF in hepatocytes derived from regenerating liver was relatively the same for male- and female-derived hepatocytes, but the magnitude of the response was considerably higher in male-derived hepatocytes. In contrast, in vivo DNA synthesis in the liver remnant after partial hepatectomy was similar in male and female rats if measured 24 h after the operation. A comparison of EGF binding to male- and female-derived hepatocytes maintained in primary culture indicated a lower number of high-affinity receptors for EGF in the female hepatocytes. The addition of estrogen to primary cultures of hepatocytes isolated from male rats inhibited EGF binding as well as EGF-induced DNA synthesis. Our studies show significant differences in DNA synthesis in response to EGF when male and female hepatocytes are compared in primary culture. The regenerative response after partial hepatectomy, on the other hand, was the same in male and female rats. Thus, our studies indicate that the sex of the donor, rat is important when hepatocytes in culture are used for a variety of studies, such as hepatocyte metabolism, induction and control of DNA synthesis, and hepatocarcinogenesis. In addition, our results indicate that caution is advised when inferences are made from in vitro findings for in vivo conditions.

Animals↗
PubMed1987

Selective synthesis and retention of 66k protein in a human neuroblastoma cell line (NCG) treated with a cytotoxic dosage of delta 12-prostaglandin J2.

delta 12-prostaglandin(PG)J2 (7.5 micrograms/ml) significantly inhibited protein synthesis and cell growth in a human neuroblastoma cell line (NCG), decreasing these factors by 31.5% and 78.2% of the control values, respectively. Two protein synthesis inhibitors, cycloheximide (CHM) and emetine, exhibited a dose-dependent protective effect for neuroblastoma cells against delta 12-PGJ2 cytotoxicity. At a concentration of 15 micrograms/ml CHM, the number of viable cells increased from 21.8% to 36.7% of the control value (p less than 0.01). The sodium dodecyl sulfate-polyacrylamide gel analysis of [35S]methionine-incorporated proteins revealed an increased synthesis of 86k, 70k and 66k proteins in the delta 12-PGJ2-treated NCG cells under the condition that delta 12-PGJ2 exerts cytotoxicity. Of these proteins, the amount of 66k protein was particularly increased in cell cytosol; however, its synthesis did not occur when CHM prohibited the delta 12-PGJ2 cytotoxic effect. When emetine was used instead of CHM, similar results were obtained. These results strongly suggest that the 66k protein plays a critical role in the delta 12-PGJ2 cytotoxicity.

Cell Division↗
PubMed1987

Fatty acid modification of cultured neuroblastoma cells by gamma linolenic acid relevant to its antitumor effect.

Two human neuroblastoma cell lines, NCG and GOTO, were used to study the cytotoxic effect of gamma linolenic acid (GLA). The cell growth inhibition of these culture cells by GLA was found to be associated with striking membrane fatty acid modification. When culture cells were exposed to 20 micrograms/ml and 60 micrograms/ml GLA for 48 hr, polyenoic acids in cell membrane phospholipids (PC, PE, PI, PS) and triglyceride significantly increased; 1.8-21.0 fold for NCG and 1.04-11.5 fold for GOTO, in association with decreased monoenoic acids. The most remarkable changes were; increase of C18:3, C20:3, C20:4 and decrease of C18:1. CoQ10 (50 micrograms/ml) and vitamin E (10 microM) shown to protect against the cytotoxic effect of GLA did not modify the incorporation of GLA into tumor cells. These results indicate that the antitumor effect of GLA is probably due to cellular dysfunction caused by fatty acid modification after GLA incorporation.

Antineoplastic Agents↗
PubMed1987

Effects of 5-bromo-2'-deoxyuridine on arachidonic acid metabolism of neuroblastoma and leukemia cells in culture: a possible role of endogenous prostaglandins in tumor cell proliferation and differentiation.

Effects of 5-bromo-2'-deoxyuridine (BrdU) were studied on two neuroblastoma and two leukemia cell lines, in terms of the relationship between prostaglandin (PG) synthesis and cell growth/differentiation. After treatment with BrdU (5 micrograms/ml), cell growth of the 4 cell lines was inhibited and one neuroblastoma cell line (GOTO) showed flattened morphology with positive S-100 protein, one of the differentiation markers for Schwann or glial cells. In the 4 cell lines, BrdU treatment reduced [1-(14)C]-arachidonic acid incorporation into phosphatidylinositol and phosphatidylethanolamine and was associated with an increase into phosphatidylcholine and triglyceride. BrdU treatment also increased fractions of 6-keto-PGF1 alpha and PGF2 alpha, with a decreased TXB2 fraction. The decreased ratio of TXB2/6-keto-PGF1 alpha or increased 6-keto-PGF1 alpha fraction correlated significantly with cell growth inhibition, suggesting that the changes in the balance of endogenous PGs might be associated with BrdU-induced cell growth inhibition with or without differentiation of neuro-blastoma and leukemia cells in culture.

Arachidonic Acid↗