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Biomedical subjects

K Sugioka

Publications and source records attributed to K Sugioka.

At least 37 records · Page 2Linked to original sources
PubMed1988

A new and suitable reconstructed system for NADPH-dependent microsomal lipid peroxidation.

In order to evaluate the O-2 participation in NADPH-dependent microsomal lipid peroxidation, we used reconstructed system which contained detergent-solubilized NADPH-dependent cytochrome P-450 reductase, cytochrome P-450, phospholipid liposomes, NADPH and Fe3+-ADP. Lipid peroxidation, monitored by the formation of thiobarbituric acid-reactive substance, was increased with increasing concentration of detergent-solubilized NADPH cytochrome P-450 reductase, cytochrome P-450 or Fe3+-ADP. Cytochrome P-450-dependent lipid peroxidation was parallel to O-2 generation monitored by chemiluminescence probe with 2-methyl-6-(p-methoxyphenol)-3,7-dihydroimidazo[1,2-a]pyrazin++ +-3-one. Lipid peroxidation was significantly inhibited by superoxide dismutase, but not by catalase or sodium benzoate. The reconstructed system herein described is considered to be very close to NADPH-dependent microsomal lipid peroxidation system.

Animals↗
PubMed1988

Properties of a coenzyme, pyrroloquinoline quinone: generation of an active oxygen species during a reduction-oxidation cycle in the presence of NAD(P)H and O2.

The oxidation of NAD(P)H by pyrroloquinoline quinone (PQQ) was non-enzymatically carried out at physiological pH in the presence of O2. The PQQ-NAD(P)H system requires about 1 mol of O2 for the oxidation of 1 mol of NAD(P)H. The oxidation of NAD(P)H occurred at a pseudo-first-order rate with respect to NAD(P)H and was of zero order with respect to PQQ concentration in in the presence of O2: k0[PQQ] [NAD(P)H] = k1 [NAD(P)H], where k0[PQQ] = k1, in which [PQQ] represents the initial concentration of PQQ. k0 values for NADH and NADPH were 3.4.10(2) M-1.min-1 and 2.0.10(2) M-1.min-1, respectively, at 25 degrees C and at 258 microM O2 (initial concentration). The system produced O-2, probably by the interaction of PQQ.H and/or NAD(P).with O2, during the oxidation of NAD(P)H. PQQH2 and PQQ.H were easily oxidized to PQQ in the presence of O2, yielding H2O2.

Coenzymes↗
PubMed1987

A ferriprotoporphyrin IX-chloroquine complex promotes membrane phospholipid peroxidation. A possible mechanism for antimalarial action.

The effect of a ferriprotoporphyrin IX-chloroquine complex on phospholipid membranes was investigated on the basis of iron-induced lipid peroxidation using microsomal phospholipid liposomes. The ferriprotoporphyrin IX-chloroquine complex remarkably promoted peroxidative cleavage of unsaturated phospholipids in liposomes, compared with ferriprotoporphyrin IX alone. Neither the combination of protoporphyrin IX with chloroquine nor the combination of Fe3+-ADP with chloroquine promoted lipid peroxidation. DL-alpha-Tocopherol completely inhibited lipid peroxidation induced by the ferriprotoporphyrin IX-chloroquine complex.

Chloroquine↗
PubMed1987

Novel and potent biological antioxidants on membrane phospholipid peroxidation: 2-hydroxy estrone and 2-hydroxy estradiol.

Catechol estrogens, 2-hydroxy estrone, 2-hydroxy estradiol and 2-hydroxy estriol, were tested as possible antioxidants of phospholipid peroxidation induced by Fe3+-ADP-adriamycin, using phospholipid liposomes as lipid source and alpha-tocopherol or other steroids as reference compounds. The parameters of antioxidant activities were: elongation of induction period, inhibition of O2 consumption required for lipid peroxidation and inhibition of peroxidative cleavage of unsaturated phospholipid. Of the tested compounds, 2-hydroxy estradiol or 2-hydroxy estrone had more potent activity than that of tocopherol.

Adenosine Diphosphate↗
PubMed1987

Estrogens as natural antioxidants of membrane phospholipid peroxidation.

Estrogens, such as estrone, estradiol and estriol, were tested as possible antioxidants of lipid peroxidation induced by Fe3+-ADP-adriamycin or Fe3+-ADP-ascorbate. The estrogens with phenolic structure possessed substantial activities with respect to the inhibition of lipid peroxidation. Concentrations of estradiol and estriol required to achieve 50% inhibition of membrane phospholipid peroxidation were about 4- and 6-times that of alpha-tocopherol, respectively.

Animals↗
PubMed1987

Selecting the patient for major ambulatory surgery. Surgical and anesthesiology evaluations.

In assessing the patient as a candidate for major ambulatory surgery, the surgeon must make an individual and specific judgment concerning the suitability of each patient. Factors to be considered include the patient's age, general physical and mental condition, anesthetic risk, attitudes about ambulatory surgery, and social and family situation, as well as whether the current standards and customs for ambulatory surgery in that community encompass the proposed procedure. Candidates for anesthesia can be ranked with the classification of the American Society of Anesthesiologists.

Aging↗
PubMed1987

Arterial oxygen tensions measured continuously in patients breathing 21% oxygen and nitrous oxide or air.

Changes in arterial oxygen tensions in nine anaesthetized patients during controlled ventilation with either 79% nitrous oxide in oxygen or air only, were measured continuously using an intra-arterial oxygen electrode. When the patients were ventilated with the mixture, there was a significant increase in PaO2 of 2.74 +/- 1.08 kPa (P less than 0.002) over control values obtained while the subjects were awake and breathing air spontaneously. Changing the inspired gas from nitrous oxide in oxygen to air while ventilation was held constant resulted in a significant decrease in PaO2 of 2.22 +/- 0.94 kPa (P less than 0.001). However, these PaO2 values were not statistically significantly different from control values. We conclude that continuous accurate measurement of arterial oxygen tension is feasible provided that corrections are made in the electrode system for anaesthetic gases. We also found that the increase in PaO2 when 79% nitrous oxide in 21% oxygen was used, when compared with air, was lower than values proposed by previous investigators. The decrease in PaO2 when the inspired gas was changed back to room air was less than that found by others and there was no evidence of hypoxia when patients were ventilated on air alone after inspiring the mixture.

Adolescent↗
PubMed1987

ESR studies on the active intermediate in the enzymatic reduction of the Fe-bleomycin complex.

The spin trapping method was applied to elucidate the active intermediate during the enzymatic reduction of Fe(III)-bleomycin in the presence of NADPH-cytochrome P-450 reductase and O2. Although the hydroxyl adducts to spin traps were observed, the adduct formation was not inhibited by catalase nor by SOD. Furthermore, in Tris-HCl buffer, no Tris adduct to the spin trap was observed. The results lead to the conclusion that there is no participation of free OH radical in the reactive intermediate in this reduction system. Effect of phosphate buffer on the reactivity of Fe(II)-bleomycin and spin state of Fe(III)-bleomycin were discussed.

Animals↗
PubMed1987

Importance of two iron-reducing systems in lipid peroxidation of rat brain: implications for oxygen toxicity in the central nervous system.

The mechanism of lipid peroxidation in the central nervous system has been studied using oxygen-flushed rat brain homogenates at pH 7.4. Brain lipid peroxidation was monitored by chemiluminescence and by determination of thiobarbituric acid-reactive substances. Less involvement of O2-., H2O2 and probably .OH in the initiation of lipid peroxidation was indicated. Deferroxamine was an extremely potent inhibitor of lipid peroxidation, suggesting that lipid peroxidation was catalyzed by endogenous iron. Brain tissues were shown to contain at least two iron-reducing systems for promotion of lipid peroxidation. One was ascorbate-dependent and the other NADPH-dependent. The former was much more potent than the latter with respect to iron-reducing activity.

Animals↗
PubMed1986

A chemiluminescent probe with a Cypridina luciferin analog, 2-methyl-6-phenyl-3,7-dihydroimidazo[1,2-a]pyrazin-3-one, specific and sensitive for O2- production in phagocytizing macrophages.

When a Cypridina luciferin analog (the title compound) was added to a macrophage suspension in Hank's balanced salt solution (control), the system emitted a weak, but detectable light, which was not altered in the presence of superoxide dismutase. The same system, however, emitted a much stronger light, just after the addition of a trigger, opsonized zymosan. The luminescence was suppressed to the control level in the presence of superoxide dismutase, while it was only slightly influenced, if at all, by NaN3, a scavenger of singlet oxygen and an inhibitor of myeloperoxidase. Some other results obtained also indicate the participation of O2- in the luciferin analog-dependent luminescence in macrophages during phagocytosis.

Animals↗
PubMed1986

Chemiluminescence probe with Cypridina luciferin analog, 2-methyl-6-phenyl-3,7-dihydroimidazo[1,2-a]pyrazin-3-one, for estimating the ability of human granulocytes to generate O2-.

The Cypridina luciferin analog, 2-methyl-6-phenyl-3,7-dihydroimidazo[1,2-a]pyrazin-3-one (CLA), in Hanks' balanced salt solution, emitted a weak luminescence which was not affected by superoxide dismutase or catalase and was not augmented by resting human granulocytes. In contrast, activated granulocytes caused a dramatic increase in the luminescence of CLA. The light emission by CLA in the presence of activated granulocytes was inhibited by superoxide dismutase, but not by catalase or benzoate. Azide at 0.5 mM did not inhibit light emission significantly. These results indicate that O2-, rather than H2O2, HO., singlet oxygen, or HOCl, was the agent responsible for eliciting the chemiluminescence of CLA. Moreover, the intensity of light emission by CLA correlated with the rate of production of O2- either by activated neutrophils or by the xanthine oxidase reaction.

Granulocytes↗
PubMed1985

Generation of electronically excited species during enzymatic oxidation of chlorpromazine and related compound.

Chemiluminescence in visible region was detected, during peroxidase-catalyzed oxidation of chlorpromazine at pH7.5 (but not at pH4.25) or of propericiazine, both at pH7.5 and at pH4.25. Red colored intermediates, cation radicals, were produced and decayed in all enzymatic systems used. Chemiluminescence was also detected at pH7.5, but not at pH4.25, when synthesized cation radical of chlorpromazine in water was mixed with concentrated buffer. Protonation of alkyl nitrogen in the cation radical of chlorpromazine was highly related to the appearance of luminescence. Possible mechanisms of the generation of the excited phenothiazine analogs were discussed.

Chlorpromazine↗
PubMed1985

DNA strand scission by enzymatically reduced mitomycin C: evidence for participation of the hydroxyl radical in the DNA damage.

Phage DNA, as well as plasmid and mammalian DNA's, were exposed to a superoxide and hydroxyl radical-generating system containing NADPH-cytochrome P-450 reductase and mitomycin C, both with and without added Fe3+-ADP, in phosphate buffer at pH 7.5. The generation of superoxide (O2-.) and hydroxyl (.OH) radicals in the system was demonstrated by using ESR spectrometry with N-tert -butyl-alpha-phenylnitrone (PBN) as a spin trapping agent. Only the lambda DNA isolated after exposure to the O2-./.OH-generating system containing many lower molecular weight DNA fragments indicating DNA strand breaks. This breakage was completely inhibited by a .OH radical scavenger (sodium benzoate) and by catalase, but only slightly by superoxide dismutase. Thyroid and plasmid DNA's were both cleaved when exposed to the O2-./.OH-generating systems. It is suggested that the mechanism of DNA scission by mitomycin C described here closely resembles that induced by the anthracycline drugs.

Animals↗
PubMed1984

Importance of Fe2+-ADP and the relative unimportance of OH in the mechanism of mitomycin C-induced lipid peroxidation.

The mechanism of mitomycin C-induced lipid peroxidation has been studied at pH 7.5, using systems containing phospholipid membranes (liposomes) and an Fe3+-ADP complex with purified NADPH-cytochrome P-450 reductase. Both O2- and H2O2 are generated during the aerobic enzyme-catalyzed reaction in the presence of mitomycin C. Hydroxyl radical is formed in the reaction by the reduction of H2O2. This is catalyzed by the Fe2+-ADP complex in a phosphate buffer or to a lesser extent when in a Tris-HCl buffer. The reduction of Fe3+-ADP to Fe2+-ADP is mainly achieved by O2-. The resulting Fe2+-ADP in the presence of O2 forms a perferryl ion complex which is a powerful stimulator of lipid peroxidation. However, the formation of such an iron-oxygen complex is strongly inhibited by phosphate ions, which do not interfere with the generation of OH radicals. These findings suggest that, since lipid peroxidation occurs in a Tris-HCl buffer (but not in a phosphate buffer), the OH radical is unlikely to be involved in the observed lipid peroxidation process.

Adenosine Diphosphate↗
PubMed1984

Clear evidence for the participation of OH in lambda DNA breakage induced by the enzymatic reduction of adriamycin in the presence of iron-ADP. Importance of local OH concentration for DNA strand cleavage.

lambda DNA (a double-stranded DNA) was exposed to several adriamycin-mediated active oxygen generating systems (O2- and H2O2 generating, OH generating, and perferryl ion complex generating), extracted, and analyzed by gel electrophoresis on agarose gel. Only the DNA exposed to and subsequently isolated from the adriamycin-mediated OH generating system contained many DNA fragments of low molecular weight, indicating the breakage of DNA strands. Such a breakage was strikingly inhibited by catalase or 50 mM sodium benzoate, but not by superoxide dismutase. The local OH concentration near the DNA strand was considered to be important for DNA strand cleavage.

Adenosine Diphosphate↗
PubMed1983

Generation of hydroxyl radicals during the enzymatic reductions of the Fe3+-ADP-phosphate-adriamycin and Fe3+-ADP-EDTA systems. Less involvement of hydroxyl radical and a great importance of proposed perferryl ion complexes in lipid peroxidation.

A system which contains NADPH, purified cytochrome P-450 reductase (enzyme) and Fe3+-ADP-adriamycin complex in Tris-HCl buffer does not produce hydroxyl radical, but possesses a strong lipid peroxidation activity on exogenously added phospholipid micelles. Fe3+-ADP-adriamycin complex, a tightly coordinated complex in Tris-HCl buffer, could be dissociated to Fe3+-ADP-phosphate complex and adriamycin in phosphate buffer. Hydroxyl radical, which can be detected by a spin trapping method using N-tert-butyl-alpha-phenylnitrone, is produced during the enzymatic reduction of a mixture of Fe3+-ADP-phosphate complex and adriamycin or of Fe3+-ADP-EDTA complex while it is not involved in phospholipid peroxidation under the conditions used. With hydroxyl radical-generating systems, little or no quenching of hydroxyl radical in Tris-HCl buffer could be demonstrated. The oxidative cleavage of phospholipid is initiated by the proposed perferryl ion complex, which may be generated by the interaction of Fe2+-ADP-adriamycin complex with O2. A similar perferryl ion complex is also produced during the enzymatic reduction of Fe3+-ADP-EDTA complex with a molar ratio of 2 for [Fe3+]/[EDTA] in the presence of air. This is also able to catalyze lipid peroxidation.

Adenosine Diphosphate↗