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Biomedical subjects

Y Umeda

Publications and source records attributed to Y Umeda.

At least 127 records · Page 7Linked to original sources
PubMed1984

Congenital esophagobronchial fistula in the adult.

The case of a 43-year-old man with congenital esophagobronchial fistula is presented. The patient had had bouts of coughing on swallowing liquids for 5 months. A barium swallow examination and bronchography showed an esophagobronchial fistula communicated between the middle third of the esophagus and right lower bronchus. An orifice of the fistula at the apex of an esophageal diverticulum was revealed by esophagoscopy. The clinical, operative, and histological features are discussed as well as the basis for a diagnosis of congenital origin.

Adult↗
PubMed1983

Protective activity of thymosin alpha 1 against tumor progression in immunosuppressed mice.

The effect of thymosin alpha 1 was examined in mice immunosuppressed by cytostatics or X-ray irradiation. Inoculation of B16 melanoma or L1210 leukemic cells into these immunosuppressed mice caused a high incidence of pulmonary metastasis or rapid death, respectively. Thymosin alpha 1 given concomitantly with cytostatics or after X-ray prevented such deleterious effects of these agents. One of possible mechanisms causing the rapid death and increasing the metastasis is the damage to NK cells. Thymosin alpha 1 prevented the reduction of NK cell activity caused by these agents. The preventive activity could be transferred to immunosuppressed recipients by spleen cells and those deprived of T cells, but not by those deprived of NK cells. Another possible mechanism is the aberration of the barrier system for spread of tumor cells in blood circulation, which may allow the tumor cells to migrate to various sites in the host. In 5-FU-treated mice, distribution of 125I-L1210 cells upon inoculation was higher in blood and lung, but lower in liver and spleen as compared with that in normal mice. On the other hand, when thymosin alpha 1 was given with 5-FU, the pattern of the tissue distribution was almost the same as that in normal mice. Thus, thymosin alpha 1 protected mice which received immunosuppressive agents from undesirable effects of the agents on surveillance systems against tumor. Thymosin alpha 1 may be useful as an adjuvant in cancer therapies.

Animals↗
PubMed1983

Thymosin alpha 1 restores NK-cell activity and prevents tumor progression in mice immunosuppressed by cytostatics or X-rays.

The effect of thymosin against tumor progression was examined in mice immunosuppressed by cytostatics or X-ray irradiation. When pretreated with cytostatic agents, such as 5-fluorouracil (5-FU) or BCNU, or by X-ray, and then inoculated with P388 or L1210 leukemias, mice died rapidly within a few days. In these systems, thymosin alpha 1 given concomitantly with the cytostatic agents or after X-irradiation prevented rapid death and extended survival, although the mice eventually died with leukemia like normal mice inoculated with cells of the same tumor. Rapid death in the 5-FU-treated mice was also prevented by adoptive transfer of spleen cells from the donor mice if these had been treated with 5-FU plus thymosin alpha 1, but not if they had received 5-FU alone. However, the restorative activity of the donor spleen cells was abrogated by treatment with anti-asialo GM1, but not by treatment with anti-Thy 1 or anti-mouse Ig serum, suggesting that the effector cells in the spleen are NK cells. In fact, thymosin alpha 1, when given concomitantly with 5-FU or after X-irradiation, maintained the NK activity of spleen, which was damaged by treatment with 5-FU or X-irradiation alone. The present study indicates that thymosin alpha 1 exerts a preventive activity against progression of leukemias at least in part through an effect on NK cells or their progenitor cells.

Animals↗
PubMed1983

Protective activity of thymosin against opportunistic infections in animal models.

Animal models for opportunistic infections were developed by using mice immunosuppressed by 5-FU. These mice were susceptible to various microorganisms, while normal mice had greater tolerance to such microbial infections. In these models, thymosin alpha 1 was found to protect mice against lethal infections with Candida albicans, Listeria monocytogenes, Pseudomonas aeruginosa, and Serratia marcescens when it was administered during 5-FU treatment prior to the infections. Thymosin alpha 1 was effective in some infections at 0.4-400 micrograms/kg/day IP, about 1/100 of the dose required for thymosin fraction 5. Activity was also demonstrated against L-monocytogenes and Ps. aeruginosa by counting the viable bacteria in the liver after infection. The protective activity against Candida, elimination of which macrophages were essential, was abrogated by anti-thymocyte serum and/or carrageenan, indicating that thymosin alpha 1 serves to maintain the functions of macrophages by reducing the damage to T cells by 5-FU. On the other hand, the activity against Pseudomonas infection was not affected by anti-thymocyte serum or carrageenan. It is probable that thymosin alpha 1 also exerts its effect on neutrophils without participation of T cells and macrophages.

Animals↗
PubMed1981

Regulation of neuron-specific enolase in NG108-15 hybrid cells and C6BU-1 glioma cells.

Distribution of three isoenzymes of brain enolase (2-phospho-D-glycerate hydro-lyase, EC 4.2.1.11) (alpha alpha, alpha gamma and gamma gamma forms) in clonal cell lines of neuroblastoma (NS20Y and N18TG-2), glioma (C6BU-1), and hybrid cells NG108-15, NCB20, Nbr10A, Nbr20A, N4G-B-a and N4G-C-a) was examined with a sensitive enzyme immunoassay system, that uses a rabbit antibody to rat brain enolase alpha alpha or gamma gamma. All cell lines tested were found to possess the enolase which contains gamma subunit (a neuron-specific protein), although the alpha alpha enolase (non-neuronal enolase) was the dominant from in these cells. A clonal rat glioma (C6BU-1) cell contained about 40, 1 and 0.07 microgram/mg protein of alpha alpha, alpha gamma and gamma gamma enolases, respectively, at the confluent stage. Inclusion of 1 mM dibutyryl cyclic AMP or 10 micrometers prostaglandin E1 plus 1 mM theophylline in the culture medium of a hybrid cell (NG108-15, mouse neuroblastoma x rat glioma) resulted in a more than 2-fold increase in the concentrations of alpha gamma and gamma gamma in the cell within a few days, with little change in the alpha alpha enolase concentration. A similar increase in the concentration of gamma subunit by the nucleotide (but not by prostaglandin E1 plus theophylline) was also observed in the glioma cell (C6BU-1) line. The results suggest that the gamma subunit or the neuron-specific protein can be regulated in NG108-15 and C6BU-1 cells in a cyclic AMP-dependent fashion.

Animals↗
PubMed1981

Enzyme immunoassay for antibodies in serum using a covalent chromatographic method for separation of the bound label.

A sensitive enzyme immunoassay system for the measurement of antibodies in serum was developed by the use of a separation method based on the thiol-disulfide interchange reaction. Serum samples including antibodies (anti-insulin, anti-human chorionic gonadotropin, or anti-beta-D-galactosidase) were incubated with antigens labeled with beta-D-galactosidase from Escherichia coli. Each reaction mixture was then passed through a small column (0.1 ml) of (anti-IgG)IgG-Sepharose 4B, in which the (anti-IgG)IgG had been coupled by means of a disulfide bond. The column was washed to remove the unbound label, then the antibody-bound label was eluted from the column with a buffer containing 25 mM dithiothreitol, which cleaved the disulfide bonds between the Sepharose matrix and the anti-IgG antibody molecules. By measuring the enzyme activity in the eluate, the amount of antibodies could be determined even in a serum sample which contained antibodies corresponding to as little as 0.01% of the standard antisera. Preliminary experiments showed that the present method can be used to detect the anti-insulin antibody in the sera from insulin-treated diabetic patients.

Animals↗
PubMed1981

Highly sensitive immunoassays for three forms of rat brain enolase.

Highly sensitive enzyme immunoassay systems for three forms (alpha alpha, alpha gamma, and gamma gamma) of rat brain enolase were prepared by use of specific antisera to two distinct subunits (alpha and gamma) of the isozymes and beta-D-galactosidase from Escherichia coli as label. Less than fmol-levels of the homologous dimer forms (alpha alpha and gamma gamma) could be determined with the corresponding antibody F(ab')2-bound solid-phase and the antibody Fab'-beta-D-galactosidase complex. The hybrid form (alpha gamma) could also be assayed specifically by use of the antibody to one subunit as solid-phase, and the antibody to another subunit as labelled complex with a minimum detectable sensitivity of 1 fmol.

Animals↗
PubMed1980

Improved reaction buffers for solid-phase enzyme immunoassay without interference by serum factors.

A gelatin moderately digested by a protease, was as effective as original gelatin to remove the interference by serum factors with a sandwich immunoassay for insulin. Digestion of gelatin resulted in decrease in the viscosity, and the buffer containing the digested gelatin did not show gelation at 4 degrees C. Therefore the buffer involving the digested gelatin might be widely useful for the immunoassay without interference by serum factors.

Buffers↗
PubMed1980

Rat brain enolase isozymes. Purification of three forms of enolase.

Three forms of rat brain enolase (Fletcher, L., Rider, C.C., & Taylor, C.B. (1976) Biochim. Biophys. Acta 452, 245-252), which were separable by DEAE-cellulose chromatography (referred as enolase I, enolase II, and enolase III in order of the elution), were purified with a high yield by use of column chromatographies of Sephadex G-150, Blue Sepharose CL-6B, and hydroxylapatite. About ten mg of each isozyme was obtained from 220 g of the brain with a yield of 30-50%. Sodium dodecyl sulfate gel electrophoresis of purified enolase I and enolase III showed single bands with relative mobilities corresponding to molecular weights of 49,000 (enolase I) or 46,000 (enolase III), and that of purified enolase II showed two bands corresponding to the above molecular sizes. Amino acid analysis of three forms of enolase revealed that the amount of each amino acid enolase II was midway between those of enolase I and enolase III. Antiserum to enolase I or enolase III was raised in New Zealand white rabbits. Results of immunochemical neutralization studies and immunolectrophoresis indicated that anti-enolase III was specific to the subunit of enolase III and reacted with enolase II and enolase III. However, anti-enolase I reacted not only with enolase I and enolase II, but also with enolase in various other tissues. These results support previous reports on crude preparations that enolase II was a hybrid molecule consisting of one enolase I subunit and one enolase III subunit.

Amino Acids↗
PubMed1979

Fluorometric determination of xanthine and hypoxanthine in tissue.

A method was developed to determine the total content of the oxypurines, xanthine and hypoxanthine, in animal tissues. The developed method was constructed mainly from the following successive steps: (1) conversion of the oxypurines to uric acid and hydrogen peroxidase by xanthine oxidase; (2) decomposition of the hydrogen peroxide by catalase and subsequent inactivation of this enzyme; (3) fluorometric measurement of the uric acid based on the coupled enzyme reaction of uricase and peroxidase. In applying this method to a sample containing uric acid, preliminary removal of this uric acid was necessary and this was carried out by treating the sample with uricase, followed by subsequent inactivation of this enzyme. The present method was more specific than the existing fluorometric method and permitted to measure the total content of the oxypurines (as low as 1 nmol) without mutual separation of them. The actual application of this method to the rat liver was demonstrated together with the method to prepare the tissue sample for the assay.

Animals↗