Search PubMed⌕ Search

Biomedical subjects

R Yoshida

Publications and source records attributed to R Yoshida.

At least 235 records · Page 13Linked to original sources
PubMed1981

Induction of pulmonary indoleamine 2,3-dioxygenase by interferon.

Pulmonary indoleamine 2,3-dioxygenase [indoleamine: oxygen 2,3-oxidoreductase(decyclizing)] has been found to be induced (30- to 100-fold) in the mouse after a single intraperitoneal administration of bacterial endotoxin [Yoshida, R. & Hayaishi, O. (1978) Proc. Natl. Acad. Sci. USA 75, 3998-4000] or during in vivo virus infection [Yoshida, R., Urade, Y., Tokuda M. & Hayaishi, O. (1979) Proc. Natl. Acad. Sci. USA 76, 4084-4086]. In the present study, an in vitro system with mouse lung slices was developed in which bacterial endotoxin (5 micrograms/ml)produced an induction (approximately 10-fold) of indoleamine 2,3-dioxygenase. The endotoxin was substituted by interferon from mouse L cells or mouse brain. The pulmonary enzyme activity increased almost linearly for 48 hr after addition of mouse interferon (10(4) units/ml) to lung slices. Interferon from mouse L cells or mouse brain produced a 10- to 15-fold increase in the enzyme activity, whereas that from human leukocytes was all but ineffective. The effect also was observed using highly purified L-cell interferon, prepared by poly(U) affinity column chromatography. When interferon was treated either by heat, alpha-chymotrypsin, or anti-interferon serum, such increase in the enzyme activity was diminished essentially to the same extent as seen in the antiviral activity. The increase in the enzyme activity was blocked when actinomycin D or cycloheximide was added to the slices before interferon treatment. These results suggest that the enzyme induction was produced by interferon and not by possible contaminants in the interferon preparations.

Animals↗
PubMed1981

Inhibition of interferon-mediated induction of indoleamine 2,3-dioxygenase in mouse lung by inhibitors of prostaglandin biosynthesis.

Inhibitors of fatty acid cyclooxygenase such as indomethacin (0.1 mM), phenylbutazone (0.3 mM), and aspirin (1 mM) were found to suppress almost completely the interferon-mediated induction of indoleamine 2,3-dioxygenase in mouse lung slices. However, phenacetin, an anti-inflammatory agent devoid of cyclooxygenase inhibitory activity, and sodium salicylate, a weak inhibitor of cyclooxygenase, were much less active under identical conditions. Glucocorticoids including dexamethasone, betamethasone, and cortisone, all of which are inhibitors of phospholipase A2, blocked induction of the dioxygenase by interferon in the nanomolar range, whereas other steroid hormones, such as aldosterone, testosterone, and 17 beta-estradiol, were all but ineffective. These results suggest that the enzymes phospholipase A2 and fatty acid cyclooxygenase, both of which are essential for the biosynthesis of prostaglandins, play an important role in the induction of indoleamine 2,3-dioxygenase by interferon.

Animals↗
PubMed1981

Immunohistochemical localization of indoleamine 2,3-dioxygenase in the argyrophilic cells of rabbit duodenum and thyroid gland.

To identify the cells containing indoleamine 2,3-dioxygenase, indirect immunofluorescence studies were performed using the monospecific antibody toward the enzyme purified to apparent homogeneity from rabbit small intestine. The antibody precipitated almost 100% of the enzyme activities of various organs or rabbit in a quantitatively similar manner, but did not cross-react with tryptophan 2,3-dioxygenase [L-tryptophan:oxygen 2,3-oxidoreductase (decyclizing), E.C. 1.13.11.11] in the liver. Immunohistochemical localization was studied using rabbit tissue because of the species-specific reactivity of the antibody. In the duodenum, indoleamine 2,3-dioxygenase-immunoreactive cels were found to be sporadically but exclusively localized in the mucosa, a large number being in the basal portion. No staining was seen in the consecutive sections treated with control immunoglobulin. Restaining within the same section using Grimelius' silver technique revealed that the immunoreactive cells coincided with the argyrophilic cells reportedly containing serotonin under physiological conditions. In the thyroid gland, the immunofluorescence was positive in the cluster of the parafollicular cells also shown to be argyrophilic, the cells proposed to have a monoamine-handling capacity specific for serotonin. These results indicate that indoleamine 2,3-dioxygenase is present in those cells rich in serotonin or active in serotonin biosynthesis and further support our previous contention that the enzyme may play an important role in the regulation of the metabolism of indoleamines and their precursors in such cells.

Animals↗
PubMed1980

Stereospecificity of hepatic L-tryptophan 2,3-dioxygenase.

Tryptophan 2,3-dioxygenase [L-tryptophan--oxygen 2,3-oxidoreductase (decyclizing), EC 1.13.11.11] has been reported to act solely on the L-isomer of tryptophan. However, by using a sensitive assay method with D- and L-[ring-2-14C]tryptophan and improved assay conditions, we were able to demonstrate that both the D- and L-stereoisomers of tryptophan were cleaved by the supernatant fraction (30000 g, 30 min) of liver homogenates of several species of mammals, including rat, mouse, rabbit and human. The ratio of activities toward D- and L-tryptophan was species variable, the highest (0.67) in ox liver and the lowest (0.07) in rat liver, the latter being hitherto exclusively used for the study of hepatic tryptophan 2,3-dioxygenase. In the supernatant fraction from mouse liver, the ratio was 0.23 but the specific activity with D-tryptophan was by far the highest of all the species tested. To identify the D-tryptophan cleaving enzyme activity, the enzyme was purified from mouse liver to apparent homogeneity. The specific activities toward D- and L-tryptophan showed a parallel rise with each purification step. The electrophoretically homogeneous protein had specific activities of 0.55 and 2.13 mumol/min per mg of protein at 25 degrees C toward D- and L-tryptophan, respectively. Additional evidence from heat treatment, inhibition and kinetic studies indicated that the same active site of a single enzyme was responsible for both activities. The molecular weight (150000), subunit structure (alpha 2 beta 2) and haem content (1.95 mol/mol) of the purified enzyme from mouse liver were similar to those of rat liver tryptophan 2,3-dioxygenase. The assay conditions employed in the previous studies on the stereospecificity of hepatic tryptophan 2,3-dioxygenase were apparently inadequate for determination of the D-tryptophan cleaving activity. Under the assay conditions in the present study, the purified enzyme from rat liver also acted on D-tryptophan, whereas the pseudomonad enzyme was strictly specific for the L-isomer.

Animals↗
PubMed1980

Circulating immune complexes in patients with neoplastic disorders.

A group of 100 patients with various neoplastic disorders and 25 healty subjects were studied by the 125I-Clq and 125I-mRF inhibition tests for the presence of circulating immune complexes in the sera. The presence of circulating immune complexes was detected in 32 and 23% of the 100 patients by the 125I-Clq inhibition test and 125I-mRF inhibition test, respectively. A discrepancy between the two radioimmunoassays in cancer sera may suggest a possibility of the occurrence of quantatively different types of circulating immune complexes in neoplastic disorders.

Antibodies, Neoplasm↗
PubMed1979

Induction of indoleamine 2,3-dioxygenase in mouse lung during virus infection.

Indoleamine 2,3-dioxygenase [indoleamine: oxygen 2,3-oxidoreductase (decyclizing)] activity in the supernatant fraction (30,000 X g, 30 min) of mouse lung homogenate increased approximately 120-fold after infection with PR8 influenza virus. Both specific and total enzyme activities started to increase linearly from the 5th day after infection, reached the highest level around the 11th day, and then gradually decreased to normal values in about 3 weeks. Other enzymes in the lung, such as certain lysosomal enzymes and monoamine oxidase, did not change significantly throughout the experiments. The time course of the increase in the enzyme activity was quite different from that of virus replication in the lung (a peak by the 3rd day and persistence until the 9th day) or that of serum antibody content (started to rise on the 9th day). Rather, it appeared to be closely related to the infiltrations of mononuclear and lymphocytic cells. When mice were exposed to a higher dose of virus and did not recuperate, the time course of the increase of the enzyme activity was essentially identical to that seen with a low concentration of virus. A maximum stimulation of the enzyme activity in the lung occurred on the 9th day after infection; the increase was approximately 100-fold. However, serum antibody content was slight and virus titer in the lung remained high.

Amines↗
PubMed1979

Computed tomographic findings in subacute sclerosing panencephalitis.

We used a computed tomography to look for evidence of cerebral changes in a three-year-10-month-old girl with SSPE. The area of decreased density on CT corresponded to inflammatory and demyelinative lesions in the brain. CT scans seem to be a useful tool for more accurate assessment in the diagnosis of SSPE.

Brain↗
PubMed1978

Induction of pulmonary indoleamine 2,3-dioxygenase by intraperitoneal injection of bacterial lipopolysaccharide.

Indoleamine 2,3-dioxygenase [indoleamine: oxygen 2,3-oxidoreductase (decyclizing)] activity in the supernatant fraction (30,000 X g, 30 min) of the mice lung homogenate increased approximately 30- to 50-fold after an intraperitoneal administration of bacterial lipopolysaccharide. In all other tissues tested, no significant increase in enzyme activity was observed. The effect appeared to be specific for the lipopolysaccharide fraction because glycogen and zymosan were almost ineffective under the same experimental conditions. In the lung, the enzyme activity increased almost linearly during the first 24 hr after a single injection of the lipopolysaccharide fraction (20 microgram per mouse). The enzyme activity started to decrease after 48 hr and reached a normal value after about 6 days. The increase in enzyme activity was completely abolished by cycloheximide or actinomycin D. Other enzymes in the lung such as beta-glucuronidase, acid phosphatase, and monoamine oxidase did not change significantly with this treatment.

Animals↗