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R Shinohara

Publications and source records attributed to R Shinohara.

At least 37 records · Page 2Linked to original sources
PubMed1989

[Detection methods of free radical related substances and the system for their elimination].

Lipid peroxide and SOD were selected as free radical related substances and system for their elimination, and detection was evaluated. NADPH-Cytochrome c reductase-Neotetrazolium (NT) method (Mic-NT method) and Xanthine oxidase-Nitrotetrazolium Blue method (XOD-NTB method) are current detection methods of SOD activities. They are based on the O2-specific reaction. Minimum detectable amount of SOD by the Mic-NT method and XOD-NTB method was about 15 ng and 200 ng, respectively. On the other hand, an XOD-NH2OH method which detects SOD activities based on the O2-specific oxidation reaction showed the minimum detectable amount of 2.5 ng. Consequently, SOD-detecting sensitivity of these methods was found to be in the following order: XOD-NH2OH method greater than Mic-NT method greater than XOD-NTB method. In addition, albumin caused a positive error in all three methods. With a monoclonal antibody-aided SOD-analyzing method (EIA method), the minimum detectable amount of SOD was 0.2 ng. The isoenzymes of SOD (Cu, Zn-SOD and Mn-SOD) could be detected separately by 1. deactivating Cu, Zn-SOD with CN- or H2O2 and regarding the remaining activity as Mn-SOD and 2. by deactivating Mn-SOD selectively through pretreatment of the sample with SDS and regarding the remaining activity as Cu, Zn-SOD. TBA method (Yagi's method) has been used frequently for the measurement of serum lipid peroxide.(ABSTRACT TRUNCATED AT 250 WORDS)

Albumins↗
PubMed1989

[Studies on the behavior of lipid peroxide in reperfusion induced arrhythmia].

Lipid peroxidation of the cell membrane is one of the most important factors of reperfusion induced arrhythmia (RIA). To determine the role of lipid peroxidation in RIA, lipid peroxide (LPO) and superoxide dismutase (Total, Mn-SOD) were examined in this experiment. Thirty-four male Donryu strain rats (250-350 g body weight) were studied. After left thoracotomy and 5-minute ligature of LAD coronary artery, reperfusion was done under artificial ventilation with room air. The electrocardiogram (ECG) was recorded via standard limb leads. Twenty-four rats were divided into 5 groups and the heart tissue and blood samples were collected 1. preligature 2. after 1-minute ligature 3. after 4-minute ligature 4. 1-minute after declamping and 5. 10-minute after declamping. To examine the correlation between LPO and duration of RIA, samples from another 10 rats were collected as soon as RIA disappeared. LPO, SOD, CPK, and MDH (malate dehydrogenase) were measured in all samples. The total SOD level in heart tissue decreased after reperfusion (p less than 0.05). The heart tissue LPO (t-LPO) decreased after ligature (p less than 0.05), but each value in 2. to 5. was lower than 1., and no increase was found after reperfusion. A negative correlation of R = 0.87 (p less than 0.01) was found between t-LPO and RIA duration, but a positive correlation of R = 0.79 (p less than 0.01) was found between t-LPO and CPK. Moreover, the LPO level was lower in the RIA occurrence group than in the non-occurrence group (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

[Changes in mucosal superoxide dismutase activities of gastric lesions].

The mucosal superoxide dismutase (SOD) activities were serially examined on the acute gastric mucosal lesion (AGML) induced by water-immersion restraint stress to rats for six hours. The mucosal SOD activities gradually increased in proportion to the time up to 3 hours after the restraint stress. But it decreased 6 hours after when severe damage had been established in the mucosa. On the other hand, the mucosal SOD activities of the margins of human gastric ulcer showed to be higher on the healing stage than on the active stage. And the SOD activities of the intractable ulcer were lower than those of the curable ulcer. These results indicate that the mucosal SOD may play some important roles both on the protecting process information of AGML and on the healing process in gastric ulcer.

Adult↗
PubMed1984

Anthranilic acid metabolism in the isolated perfused rat liver: detection and determination of anthranilic acid and its related substances using high-performance liquid chromatography with electrochemical detection.

In order to elucidate the anthranilic acid metabolism in animal tissue, the metabolism was studied in the isolated perfused liver of rats. A sensitive and rapid method was devised for determination of anthranilic acid and its related substances using high-performance liquid chromatography with electrochemical detection. 5-Hydroxyanthranilic acid and anthranilamide, which have not been detected in animal tissue, were found in the perfusate and in the bile secreted from the perfused liver, respectively. In addition, a non-enzymatic production of anthranilamide from anthraniloyl glucuronide in the presence of ammonium and bicarbonate ions was also observed. These present results suggest that, apart from undergoing glycine or glucuronide conjugation, anthranilic acid is metabolized to 5-hydroxyanthranilic acid and anthranilamide in the rat liver.

Animals↗
PubMed1984

Role of cytosolic superoxide dismutase as a stimulator in anthranilamide hydroxylation by a microsomal monooxygenase system in rat liver.

We have isolated a protein factor from rat liver which stimulates anthranilamide hydroxylation by the microsomes in the presence of NADPH and oxygen and showed this factor to contain Cu and Zn and to have superoxide dismutase activity [Biochim. Biophys. Acta 365, 148-157 (1974)]. In the present study, this protein factor was confirmed to be a superoxide dismutase (SOD) by comparison of the recovery of SOD activity with that of anthranilamide hydroxylation-stimulating activity at each step of its purification, by inhibition of SOD activity with NaCN and hydrogen peroxide (H2O2), and by recovery of the SOD activity of the protein factor after reconstitution with Cu2+ and/or Zn2+. At a given SOD activity level, there was no difference among the rat liver SOD, Cu,Zn-SOD from bovine erythrocytes, and Mn-SOD from Serratia marcescens in their ability to stimulate anthranilamide hydroxylation not only by rat liver microsomes, but also by the reconstituted cytochrome P-450-containing monooxygenase system. Rat liver SOD stimulated anthranilamide hydroxylation by the reconstituted system in proportion to its amount below a protein concentration of 1 microgram/ml. In anthranilamide hydroxylation by the reconstituted system without SOD, only a slight hydroxylase activity was found at the initial stage of the reaction and a marked increase in the amounts of NADPH oxidized and H2O2 formed was observed after a lag time. In the presence of rat liver SOD, however, the hydroxylase activity was markedly and continuously increased almost proportionally to reaction time with a concomitant decrease in the amounts of NADPH oxidized and H2O2 formed. In addition, a trace of 3-OH anthranilamide, one of the products, not only stimulated NADPH-dependent H2O2 formation in the reconstituted system, but also inhibited the apparent reduction of cytochrome P-450 by NADPH in the reconstituted system. These effects of 3-OH anthranilamide were diminished by rat liver SOD. When a trace of 3-OH anthranilamide were added to a system composed of NADPH-cytochrome c (P-450) reductase and NADPH, H2O2 formation and NADPH oxidation were markedly stimulated. However, on addition of 3-OH anthranilamide to the system containing rat liver SOD, no stimulation on either H2O2 formation or NADPH oxidation was found.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1984

Effect of superoxide dismutase on hydroxylase activity and hydrogen peroxide formation in anthranilamide hydroxylation by a rat liver microsomal monooxygenase system.

Anthranilamide was slightly hydroxylated by a reconstituted rat liver microsomal monooxygenase system with NADPH, but a large amount of hydrogen peroxide was formed with a consumption of NADPH during the reaction. Superoxide dismutase stimulated the hydroxylation by depressing the hydrogen peroxide formation, in that there was a reverse correlation between the two effects due to the dismutase. In addition, a trace of 3-hydroxyanthranilamide, one of the products, not only stimulated NADPH-dependent hydrogen peroxide formation via NADPH-cytochrome c (P-450) reductase, but also inhibited the reduction of cytochrome P-450 by NADPH in the reconstituted system. These effects of 3-hydroxyanthranilamide were also diminished by superoxide dismutase.

Animals↗
PubMed1977

New formamidase having substrate specificity for o-formylaminoacetophenone in pig liver.

The supernatant (13 000 x g, 20 min) of pig liver homogenate was filtered with Sephadex G-200 and formamidase (aryl-formylamine amidohydrolase, EC 3.5.1.9)activity in each fraction was measured. When formylkynurenine was used as substrate, two peaks of formamidase activity were observed but, with formylaminoacetophenone as substrate, only one peak was observed. Formamidase in the lower molecular weight fraction is known as kynurenine formamidase (FA I), formamidase found here in the higher molecular weight fraction has not been previously reported. This form, designated FA II has been purified about 160-fold from pig liver. The formamidase obtained has substrate specificity for o-formylaminoacetophenone only and could not hydrolyze formylkynurenine. The optimal pH was 8.5 and the Km for o-formylaminoacetophenone was 1.66-10(-3) M. This formamidase was considered to be a new enzyme and was different from FA I in molecular weight and substrate specificity. This new formamidase was present in pig, rabbit and guinea pig liver and not present in rat or mouse liver.

Acetophenones↗