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Biomedical subjects

T Okabe

Publications and source records attributed to T Okabe.

At least 397 records · Page 22Linked to original sources
PubMed1985

Establishment of a human carcinoembryonic antigen (CEA)-producing cell line in a protein-free chemically defined medium.

To examine whether a human carcinoembryonic antigen (CEA)-producing cell can proliferate and sythesize CEA in vitro in culture without protein supplements, long-term cultivation of such cells was carried out in a protein-free chemically defined medium. Using stepwise decreases in fetal bovine serum concentration, continuous growth of the cells was established in a protein-free am's F-12 medium. The cells, designated as HLC-Yl, have been propagated in this medium for 3 years. The population doubling time of the cells is about 52 h. Addition of the serum stimulated the cell growth (population doubling time = 27 h). Saturation density was not increased by the addition of serum. The cells grown in a protein-free F-12 secrete large amounts of CEA (65.4 +/- 2.6 ng/10(6) cells/24 h). Addition of serum did not stimulate the production of CEA. The cells produced tumours when inoculated into athymic nude mice. The mice bearing the tumour showed high serum CEA levels, and CEA was demonstrated in the tumour tissue by the immunoperoxidase method. The present study suggests that cells grown in a protein-free medium do not require serum components for their growth or CEA synthesis and provide an excellent model for better understanding the growth and production of CEA in human lung cancer cells.

Animals↗
PubMed1985

Restriction fragment length polymorphism of the insulin gene region in Japanese diabetic and non-diabetic subjects.

A polymorphic locus flanking the 5' end of the insulin gene was studied in 154 unrelated Japanese diabetic and nondiabetic subjects. A predominance of the small allele was found with the following frequency: of 64 nondiabetic subjects, only 3 of 128 alleles were of the large class (2%); none of 78 alleles were of the large class in 39 Type 1 (insulin-dependent) diabetic subjects, and 4 of 102 alleles (4%) were of the large class in 51 Type 2 (non-insulin-dependent) diabetic subjects. The very low frequency of large allele may relate to the lower prevalence of atherosclerosis in Japanese. However, this possibility requires further examination.

Alleles↗
PubMed1985

Oxytocin and glucose oxidation in the rat uterus.

The effects of oxytocin on the biochemical pathways of glucose oxidation were investigated in the rat uterus. In the presence of oxytocin, glucose oxidation in uterine segments obtained from Sprague-Dawley rats at diestrus increased 1.5-2.0-fold above the basal rate. A half-maximal response was observed at about 3 nM oxytocin; the maximum response was equal to or greater than the response to 1.7 nM insulin. In stripped myometrial segments (denuded of the endometrial component), oxytocin stimulated glucose oxidation at estrus only; whereas in intact uterine segments, the stimulation of oxidation was observed at both estrus and diestrus. In contrast, stimulation of oxidation by carbachol in stripped myometrial segments was independent of the estrous state of the tissue. The ratio of [1-14C]glucose to [6-14C]glucose oxidation was measured to estimate the relative involvement of the pentose phosphate and the tricarboxylic acid pathways of metabolism. In myometrial tissue, stimulation of glucose oxidation by oxytocin appeared to proceed through the tricarboxylic acid cycle. In intact uterine segments, at diestrus, glucose oxidation involved largely the pentose phosphate pathway (suggesting increased glucose metabolism in endometrial tissue), whereas at estrus, in the intact tissue segments, oxytocin increased glucose oxidation largely via the tricarboxylic acid cycle, and appeared to do so predominantly in the myometrial tissue. Carbachol-stimulated glucose oxidation appeared to proceed mainly via the tricarboxylic cycle in the myometrial tissue, irrespective of the stage of the estrous cycle. In the uterus of the Brattleboro rat (either intact uterine segments or stripped myometrial strips), oxytocin stimulated glucose oxidation only at estrus, predominantly through the tricarboxylic acid cycle. These findings suggest that oxytocin, in addition to its known effect on the contractility of uterine and myoepithelial smooth muscle, may regulate glucose metabolism in both the myometrial and endometrial components of uterine tissue.

Animals↗
PubMed1985

A platelet factor stimulating the proliferation of vascular endothelial cells. Partial purification and characterization.

Platelets have been shown to contain a novel growth factor that stimulates the proliferation of vascular endothelial cells in vitro. The factor potently stimulated both DNA synthesis and proliferation rate in serum-deprived endothelial cells. Gel exclusion chromatography showed at least two peaks of activity on endothelial cells, the major peak being at an apparent molecular weight of 20 000. Isoelectric focusing revealed that the pI of the factor was 4.0-4.8. It was adsorbed to a column of DEAE ion exchange chromatography and eluted with a salt gradient. The factor was heat-labile and trypsin-sensitive. The activity was not destroyed by a reducing agent including dithiothreitol. This factor stimulated the proliferation of vascular endothelial cells but was found to be inactive against normal rat kidney fibroblasts.

Animals↗
PubMed1985

Increased angiotensin-converting enzyme in peripheral blood monocytes from patients with sarcoidosis.

Angiotensin-converting enzyme (ACE) activity was measured in isolated peripheral blood monocytes and culture medium from 28 patients with sarcoidosis and compared with values obtained from monocytes of 25 normal control subjects. ACE activity was determined by radioimmunoassay of angiotensin II produced from angiotensin I. While there was no measurable ACE activity in monocytes or culture medium from normal controls under the conditions of our study, monocytes from patients with sarcoidosis all showed activity both in cells and culture medium. The mean ACE activity of monocytes from patients with sarcoidosis was 2.0 pg angiotensin II formed/min per 10(5) cells, and that released into medium over a 24-h interval was 30.4 pg angiotensin II/min per 10(5) cells. The monocyte ACE from patients with sarcoidosis was activated by chloride ions and inhibited by EDTA, captopril, and rabbit antiserum to purified human plasma ACE, indicating that enzymatic activity was effected specifically by ACE. Thus, our studies show a significant elevation and release of ACE by peripheral blood monocytes of patients with sarcoidosis under conditions where monocytes of normal control subjects do not demonstrate ACE activity.

Adult↗
PubMed1985

Time-dependent deformation of composite resins--compositional considerations.

The compressive yield strength and creep of 21 dental composite resins were evaluated and correlated with filler volume percent and extent of cure in the resin. In general, yield and creep of composites were more dependent upon filler volume fraction than on extent of cure. However, the types of monomers and fillers used in the composite formulation appeared to play a major role in determining the compressive characteristics of the materials.

Carbon↗
PubMed1985

Clinical application of monoclonal antibodies to small cell lung cancer.

Monoclonal antibodies to small cell lung cancer (SCLC) were produced by fusion of P3X63/AgU1 mouse myeloma cells with spleen cells from BALB/c mice immunized against intact cells of SCLC tumors grown in BALB/c athymic nude mice. The antibody TFS-2 demonstrated "pancarcinoma" reactivity showing binding to non-small cell lung cancer (NSCLC) and carcinomas derived from other organs such as stomach, pancreas, and colon. This antibody failed to react with a variety of normal tissues including lung, bone marrow, spleen, stomach, colon, and pancreas. TFS-2 showed complement-mediated cytolysis of target cells. TFS-2 had no significant effects on hematopoietic stem cells. This antibody will serve as a powerful tool for the in vitro removal of tumor cells from bone marrow, thus facilitating high-dose chemotherapy of SCLC with autologous bone marrow transplantation. In contrast, TFS-4 monoclonal antibody reacted specifically with SCLC but not with NSCLS tumors. This antibody can distinguish SCLC from NSCLC tumors in histologic diagnosis at transbronchial biopsy, and in cytological identification of tumor cells in malignant effusion, and in infiltrated bone marrow. Radiolabeled TSF-4 specifically accumulated into SCLC tumors that were implanted subcutaneously into athymic nude mice. Thus, the antibody will be useful not only for diagnosis of lung cancer but also for targeting anti-tumor agents.

Animals↗
PubMed1985

Lactoquinomycin, a novel anticancer antibiotic. I. Taxonomy, isolation and biological activity.

Lactoquinomycin, a novel basic antibiotic, was isolated from the culture broth of a soil streptomyces by repeated solvent extraction and adsorption column chromatography. Morphological, cultural and physiological studies revealed that the organism belongs to the species Streptomyces tanashiensis. The antibiotic was active against bacteria, particularly Gram-positive organisms, and neoplastic cells in vitro. Antibiotic-resistant cell sublines of L5178Y lymphoblastoma were more significantly inhibited by lactoquinomycin than the parental cell line. Lactoquinomycin was effective against Ehrlich carcinoma in mice.

Animals↗
PubMed1985

Lactoquinomycin, a novel anticancer antibiotic. II. Physico-chemical properties and structure assignment.

Lactoquinomycin, a new antibiotic, C24H27NO8, mp 151 approximately 159 degrees C (dec), FAB-MS: m/z 458 (MH+), is a basic substance, showing UV lambda MeOHmax (epsilon) 215 (37,600), 254 (10,700) and 432 nm (4,760), and IR nu CHCl3max 1790 (gamma-lactone), 1665 and 1650 (quinone) cm-1. The structure of lactoquinomycin has been elucidated by 1H NMR and ORD in comparison with those of kalafungin.

Antibiotics, Antineoplastic↗
PubMed1985

Enhancement of pyrimidine nucleoside uptake into K562 and YAC-1 cells by cadeguomycin.

Cadeguomycin markedly stimulated the uptake of thymidine, deoxycytidine and uridine into the acid-insoluble fraction of K562 human leukemic cells, but did not significantly affect adenosine incorporation. The enhancement of pyrimidine nucleoside uptake was 6 approximately 17 fold over the control. Aspartate incorporation into nucleic acid was not significantly blocked by the antibiotic, suggesting that the stimulation of pyrimidine nucleoside incorporation is not due to the inhibition of de novo pyrimidine nucleotide synthesis. Net DNA and RNA syntheses, observed by [32P]phosphate uptake, were not significantly affected by cadeguomycin. The enzymatic activity of thymidine, deoxycytidine and uridine kinases was higher in cadeguomycin-treated cells than in untreated cells, suggesting that the enhancement of pyrimidine nucleoside uptake occurs in the phosphorylation process. The stimulatory activity of cadeguomycin of thymidine uptake was reversed by guanosine and deoxyguanosine, but not by adenosine and deoxyadenosine, suggesting that intracellular metabolism and/or action of cadeguomycin is related to that of guanosine and deoxyguanosine. The stimulation of pyrimidine nucleoside incorporation by cadeguomycin was also found with YAC-1 cells, but not with the other cell lines. The enhancement effect of the antibiotic seems to be not directly related to its cytotoxicity.

Animals↗
PubMed1985

Studies on antineoplastic activity of naphthomycin, a naphthalenic ansamycin, and its mode of action.

An antibiotic, identical with naphthomycin, was isolated from a soil Streptomyces. The antibiotic displayed significant therapeutic activity by ip administration against murine tumors: Ehrlich carcinoma and IMC carcinoma implanted ip. The maximum increase of life-span was more than 169% in Ehrlich carcinoma, and 128% in IMC carcinoma. The antibiotic exhibited a potent cytotoxicity against murine leukemic cells: P388, L1210, and L5178Y. IC50 was 0.4-1.3 microgram/ml in culture. The activity of naphthomycin was reversed by SH compounds: 2-mercaptoethanol, dithiothreitol, and glutathione. DNA and RNA syntheses were more markedly inhibited by naphthomycin than protein synthesis in L5178Y cells. Approximately 50% inhibition of nucleic acid syntheses was observed at an antibiotic concentration of 2 micrograms/ml. Naphthomycin blocked alkaline phosphodiesterase obtained from L5178Y cells: IC50 was ca. 7.6 micrograms/ml. The antibiotic neither caused metaphase arrest nor prevented tubulin polymerization. The results suggest that the mechanism of cytotoxicity of naphthomycin is the inhibition of various SH enzymes, particularly those involved in nucleic acid biosynthesis. The mode of action is unique in the ansamycin group of antibiotics.

Animals↗
PubMed1985

Biological activity of cadeguomycin. Inhibition of tumor growth and metastasis, immunostimulation, and potentiation of 1-beta-D-arabinofuranosylcytosine.

Cadeguomycin retarded growth of sc solid IMC carcinoma in CDF1 mice, and pulmonary metastasis of Lewis lung carcinoma in C57BL/6 mice. The antibiotic enhanced phagocytic activity of murine peritoneal macrophages and IL-1 production by P388D1 cells. Delayed type hypersensitivity was stimulated and interferon was induced by the drug. The results suggest that cadeguomycin inhibits tumor growth and metastasis in association with modification of the immune system. The cytotoxicity of arabinosylcytosine to K562 and YAC-1 cells was markedly enhanced by cadeguomycin in culture. The combined administration of arabinosylcytosine and cadeguomycin displayed potentiation in the inhibition of growth of ip-implanted P388 leukemia and metastasis of sc-implanted P388 leukemia to the regional lymph nodes. Cadeguomycin showed low toxicity for mice.

Adjuvants, Immunologic↗