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Biomedical subjects

S Imamura

Publications and source records attributed to S Imamura.

At least 379 records · Page 21Linked to original sources
PubMed1987

Biogenic amines in the Arthus reaction.

The concentrations of serotonin, tryptamine, dopamine, and tyramine were quantitatively determined in the Arthus reaction, since the activity of histamine-N-methyltransferase (HMT), a major histamine-metabolizing enzyme that had been demonstrated to be inhibited by such biogenic amines in vitro, decreased significantly in the reaction site. The concentrations of serotonin, tryptamine, and dopamine were unchanged in dinitrochlorobenzene allergic and croton oil dermatitis except for a slight increase of tryptamine in the latter. Tyramine was unable to be demonstrated quantitatively in all specimens tested. The concentration of serotonin decreased to about 30% that of the control level until 1 hr, followed by a prominent increase to about two-fold at 6 hr after the initiation of the Arthus reaction accompanying with a concomitant decrease in HMT activity. However, the concentrations of tryptamine and dopamine were rather decreased in the reaction site, and the net decrease of two amines was far greater than the increased amount of serotonin. The decrease in HMT activity is not stoichiometrically well elucidated from these results, and therefore, the presence of other hypothetic inhibitory factors that are increased in the Arthus reaction should be suspected.

Animals↗
PubMed1987

High-performance liquid chromatographic assay of transglutaminase and its application to the purification of human erythrocyte transglutaminase and platelet factor XIII.

A high-performance liquid chromatographic method was developed for the assay of transglutaminase [EC 2.3.2.13] activity. Casein and dansylcadaverine were used as substrates and the reaction was stopped by adding an excess amount of EGTA. Casein-bound dansylcadaverine was separated from free dansylcadaverine by high-performance liquid chromatography on a TSK SW gel column on the basis of the differences in the molecular weight and hydrophobicity. The sensitivity was approximately 0.04 nmol of casein-bound dansylcadaverine in the assay mixture. With this assay method, human erythrocyte transglutaminase and platelet factor XIII were purified by successive chromatographies on DEAE-cellulose and Sephacryl S-300, which were common for both enzymes, followed by Blue Sepharose CL-6B and DEAE Bio-Gel A for erythrocyte transglutaminase or Phenyl-Sepharose CL-4B for platelet factor XIII. The purification factors and activity yields were 15,300-fold and 22% for erythrocyte transglutaminase and 43.8-fold and 33% for platelet factor XIII.

Blood Platelets↗
PubMed1987

Decreased skin superoxide dismutase activity by a single exposure of ultraviolet radiation is reduced by liposomal superoxide dismutase pretreatment.

The effect of a single exposure to UV radiation on skin superoxide dismutase (SOD) activity was examined in mice. A significant decrease in SOD activity was observed 24 and 48 h after UV irradiation, returning to the normal level by 72 h after irradiation. Decreased SOD activity after UV exposure was reduced by pretreatment with liposomal SOD (L-SOD). This protective effect of L-SOD may have potential clinical application for photodermatologic reactions.

Animals↗
PubMed1987

Anti-oxidant effects of gold compounds.

The anti-oxidant efficacy, in vitro, of the gold compounds auranofin (AF) and gold sodium thiomalate (GST) was examined by studying their effects on the generation of reactive oxygen species (ROS) using zymosan-stimulated polymorphonuclear leukocytes (PMNs) and a cell-free, xanthine-xanthine oxidase system. The oxygen species investigated were the superoxide radical anion (O2-), hydrogen peroxide (H2O2) and the hydroxyl radical (OH.). AF had an inhibitory effect on ROS production by PMNs. In particular, OH. generation was significantly suppressed in a dose-dependent fashion. AF did not inhibit ROS production in the cell-free system. GST produced only a small degree of inhibition at higher concentrations. These findings suggest that AF may play an important role in the inhibition of respiratory bursts and the generation of inflammatory reaction products. Since the products of the respiratory burst, especially potent oxidants such as OH. and H2O2, are thought to be important inflammatory mediators, it is postulated that the blockade of toxic ROS generation by AF affects rheumatoid as well as dermatological inflammation and tissue damage.

Antioxidants↗
PubMed1987

Effect of sulphasalazine and its metabolites on the generation of reactive oxygen species.

The relative in vitro anti-oxidant efficacy of sulphasalazine (salicylazosulphapyridine, SASP) and its metabolites (5-aminosalicylic acid, 5-ASA; sulphapyridine, SP) was examined by studying their effects on the generation of reactive oxygen species (ROS) using zymosan-stimulated polymorphonuclear leucocytes (PMNs) and a cell free, xanthine-xanthine oxidase system. Salicylazosulphapyridine, 5-ASA, and SP showed anti-oxidant effects to the various degrees. In particular, production of OH, which is one of the most potent reactive oxygen species, was remarkably suppressed by 5-ASA dose relatedly. These findings suggest that SASP and its metabolites play an important role in the inhibition of respiratory bursts. As the potent products of the respiratory burst by polymorphonuclear leucocytes are thought to be important inflammatory mediators, suppression of toxic reactive oxygen species generation by these agents may partly explain the therapeutic efficacy of SASP in ulcerative colitis, which is characterised by an acute mucosal inflammation dominated by polymorphonuclear leucocytes accumulation.

Adult↗
PubMed1987

Necrobiosis-lipoidica-like skin manifestation in lymphomatoid granulomatosis (Liebow).

A 58-year-old man developed 3 indurative erythematous lesions like necrobiosis lipoidica on the right lower leg. He had had similar cutaneous lesions 1.5 years previously. These had been surgically excised, and a histologic diagnosis of necrobiosis lipoidica was made at another hospital. He was diagnosed as having lymphomatoid granulomatosis by lung biopsy in our hospital. Nasal involvement was confirmed in later examinations and the skin lesions were also considered to be the cutaneous manifestation of lymphomatoid granulomatosis. This outlines that cutaneous manifestations may allow early diagnosis of lymphomatoid granulomatosis.

Biopsy↗
PubMed1987

The effect of tranilast of the generation of reactive oxygen species.

The relative in vitro antioxidant efficacy of tranilast, a new orally active anti-allergic agent, was examined by studying its effects on the generation of reactive oxygen species (ROS) using zymosan-stimulated polymorphonuclear leukocytes and the cell-free, xanthine-xanthine oxidase system. The species investigated were superoxide radical anion (O2-), hydrogen peroxide (H2O2) and hydroxyl radical (OH.). At concentrations comparable to therapeutic blood levels, tranilast reduced both H2O2 and OH. levels. The inhibitory effect of tranilast was dose-dependent and all ROS levels examined were significantly decreased at the concentration of 100 micrograms/ml. This antioxidant effect of tranilast appeared to stem from its capability to scavenge ROS because the suppression of ROS was observed in both ROS generation systems at higher concentrations, even though the possibility existed that tranilast directly inhibited nicotineamide adenine dinucleotide phosphate oxidase and/or xanthine oxidase activity. This unique anti-inflammatory pharmacological activity of tranilast suggests its potential clinical application for allergic diseases complicated with inflammation.

Anti-Inflammatory Agents↗
PubMed1987

Decreased hydroxyl radical generation from polymorphonuclear leucocytes in the presence of D-penicillamine and thiopronine.

The effect of D-penicillamine (DP) and thiopronine on the generation of reactive oxygen species (ROS) both by stimulated polymorphonuclear leucocytes (PMNs) and in a cell-free, xanthine-xanthine oxidase system was investigated. Both drugs significantly reduced hydroxyl radical (OH.) generation in the PMN system, however, increasing trends of OH. levels were noticed in a cell-free ROS generating system. Although the opposing effects on ROS levels were verified, these two agents showed a similar behaviour presumably due to their structural similarity. The properties of these agents that affect ROS levels may contribute to their beneficial and toxic actions in inflammatory as well as immunoregulatory processes of rheumatoid arthritis (RA).

Adult↗
PubMed1987

Significance of squamous cell carcinoma (SCC)-related antigens in cutaneous SCC. A preliminary report.

The serum levels of squamous cell carcinoma (SCC)-related antigens (SCC-RAG) were assayed, utilizing the radioimmunoassay kit, in six patients with cutaneous SCC, two patients with Bowen's disease, 18 patients with other benign and malignant dermatoses, and six normal subjects. The SCC-RAG titers were significantly high in three patients with invasive SCC in whom primary tumors were either comparatively large or were associated with metastatic lesions, while they remained within the normal limit in patients with smaller-sized, nonmetastatic SCC, Bowen's disease, other non-SCC dermatoses, and in normal control subjects. The SCC-RAG titers, therefore, provided a useful tumor marker for cutaneous SCC, particularly in advanced stages. In such cases, the values were clearly correlated with tumor behaviors in response to or against treatments and with the development of metastasis.

Aged↗
PubMed1986

A functional study of a case of glucagonoma exhibiting typical glucagonoma syndrome.

A 46-year-old man had a 7-year history of severe rash, which was then diagnosed as necrolytic migratory erythema. He had a weight loss of 6 kg, abnormal glucose tolerance test findings, anemia, glossitis, hair loss, and hypoproteinemia. Plasma amino acids levels were significantly decreased, and the fasting plasma glucagon (IRG) level was high at 5000 to 8000 pg/ml. Circulating IRG significantly increased after oral glucose loading, meal ingestion, and arginine infusion, and decreased with somatostatin infusion and insulin-induced hypoglycemia. No other gut or pancreatic hormone levels in plasma were elevated. Plasma IRG was eluted by gel-filtration, mainly in the position of true glucagon (MW 3500) by antiserum 30K. The rash was markedly improved after infusion of amino acids. Computerized tomography (CT) scan and celiac angiography revealed a large pancreatic tumor with multiple liver and lymph node metastases. The pancreatic tumor was totally resected, and was identified as glucagonoma by immunohistochemical technique. Since the plasma IRG levels remained high after surgery, the patient received dimethyltriazenoimidazole carboxamide therapy. After several courses of this treatment, plasma IRG levels decreased to 1000 to 2000 pg/ml, and the hepatic metastases were remarkably diminished in size.

Adenoma, Islet Cell↗
PubMed1986

Evaluation of anti-cardiolipin antibody and its cross-reactivity in sera of patients with lepromatous leprosy.

Using a sensitive and modified solid-phase radioimmunoassay for detecting anti-cardiolipin antibodies, sera of 45 patients with lepromatous leprosy were examined. Nine of the 45 (20%) showed positive levels of anti-cardiolipin antibodies. Inhibition tests revealed that these antibodies significantly cross-reacted with double-stranded (ds) DNA, but not with single-stranded (ss) DNA or extractable nuclear antigens (ENA). We describe the unique pattern of antibody cross-reactivity with cardiolipin and dsDNA in sera of patients with lepromatous leprosy.

Antigens, Nuclear↗
PubMed1986

Anti-oxidant effects of retinoids on inflammatory skin diseases.

It is well known that retinoids are effective in the treatment of various dermatological disorders. It has been reported that retinoids have inhibitory effects on the generation of superoxide (O2-) by stimulated polymorphonuclear leukocytes (PMNs). In the present study, we investigated the effects of retinoids on the generation of O2- and other reactive oxygen species (ROS), including OH., H2O2 and chemiluminescence, by zymosan-stimulated PMNs and in the xanthine-xanthine oxidase system, because these potent ROS may play an important role in PMN-mediated skin inflammation. It was found that some retinoids had antioxidant effects in the PMN system; however, apart from the effect of tretinoin and Ro 10-1670 on OH. generation, none of the retinoids studied inhibited ROS generation in the xanthine-xanthine oxidase system. On the basis of these results, we discuss a possible mechanism connected with the role of ROS by which retinoids have favourable effects on several inflammatory skin disorders.

Antioxidants↗