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Biomedical subjects

K Sugioka

Publications and source records attributed to K Sugioka.

At least 19 recordsLinked to original sources
PubMed1992

A [14C]2-deoxy-D-glucose study of brain structures related to conditioned emotional response in the rat.

We used [14C]2-deoxy-D-glucose (2-DG) to determine activated brain structures related to conditioned emotional response (CER) in rats. The experimental groups were conditioned with paired conditioned-stimulus (CS; flickering light and clicking sound) and unconditioned-stimulus (US; foot-shock) for either 25 or 50 trials. The control groups were also exposed to the same stimuli but in unpaired or random sequence. Two days after conditioning, rats were intravenously injected with [14C]2-DG and then exposed to the CS alone (CER test) in a shock box. Mean optical densities of 44 brain structures were measured with an autoradiogram, and their optical density ratios were compared by 2-by-2 (paired vs unpaired and 25 vs 50 trials) analysis of variance. Those brain structures were of 2 types; the first type showed similar changes of 2-DG uptake in both paired and unpaired groups (Areas 7 and 40 of the cerebral cortex, the habenula and the colliculus inferior), while the second type showed that 2-DG uptake increased in the paired groups but decreased in the unpaired groups (Areas 24, 10, 6, 4 and 3 of the cerebral cortex), as a function of number of trials. Because changes of 2-DG uptake in the first type structures and in Areas 3, 4 and 6 of the second type structures are regarded to reflect learning-nonspecific effects and task- or stimuli-related symmetrical activation, respectively, we concluded that Areas 24 (anterior cingulate cortex) and 10 (prefrontal cortex) were specifically related to conditioned emotional response.

Animals↗
PubMed1991

A study on the brain structures related to conditioned emotional response by means of [14C]2-deoxy-D-glucose method.

Brain structures activated during conditioned emotional response were studied by means of the [14C]2-deoxyglucose method. The experimental (CSE) animals were conditioned with paired 25 25-sec-long flicker sequences (CS) and 1-sec-long 150 V AC electric shocks (US), while the control (CSC) animals were given only 25 CS sequences. Average densities of a unit square (200 microns x 200 microns) of 47 nuclei or cortical areas in the left hemisphere were obtained from an autoradiogram and the optical density ratio (ODR), which is the relative optical density of each structure to that of the corpus callosum, was calculated. Comparison of ODRs of each structure from both groups revealed a significant increased uptake of [14C]2-deoxyglucose (P less than 0.05, Mann-Whitney U-test) in the caudal portion of area 10, area 2, area 18 and the hippocampal formation.

Animals↗
PubMed1990

O2- generation and lipid peroxidation during the oxidation of a glycated polypeptide, glycated polylysine, in the presence of iron-ADP.

Oxidation of glycated polylysine, a model compound of glycated protein, caused O2- production even at physiological pH, which could be accelerated by Fe3(+)-ADP. An enediol structure in glycated polylysine and related compounds, which could be confirmed by I2 uptake, was related to their oxidizability. Glycated polylysine was easily coordinated with Fe3+ even in the presence of phosphate at pH 7.4 and the formation of the iron complex was prevented by desferrioxamine. The exposure of unsaturated phospholipid liposomes to glycated polylysine-Fe3(+)-ADP system caused the production of a thiobarbituric acid-reacting substance, which was completely inhibited by 5 microM alpha-tocopherol or 150 microM desferrioxamine and slightly by 0.5 microM SOD. Catalase (20 micrograms/ml) and 10 mM sodium-benzoate did not affect the iron-glycated polylysine-induced lipid peroxidation, indicating no participation of an OH. in this reaction. A ferrous ion-coordinated glycated polylysine may act as an initiator of phospholipid peroxidation in the presence of oxygen. A possible mechanism of the iron-glycated polylysine-induced lipid peroxidation was discussed.

Adenosine Diphosphate↗
PubMed1990

The ability of granulocytes to generate superoxide anions and hypochlorite during phagocytosis: comparison of neonatal granulocytes with adult granulocytes.

The ability of granulocytes to generate superoxide anions (O2-) and hypochlorite (OCl-) during phagocytosis was investigated using peripheral blood samples from adults and cord blood samples from neonates, using the chemiluminescence probe cypiridina luciferin analog (CLA) for O2- generation and luminol (L) for OCl- generation. OCl- generation by granulocytes was also monitored by taurine chloramine formation. The chemiluminescence probe based upon CLA was highly specific for and sensitive to O2- and could be adopted to determine O2- generation in terms of xanthine oxidase units. The CLA-dependent chemiluminescence by cord blood granulocytes was significantly higher than that by normal adult granulocytes. Taurine chloramine formation was significantly correlated with the L-dependent chemiluminescence (L-CL). Thus, the L-CL is considered to be mainly involved in OCl- generated by phagocytizing granulocytes. L-CLs by cord blood granulocytes and normal adult granulocytes were essentially the same during phagocytosis.

Adult↗
PubMed1988

Mechanism of O2- generation in reduction and oxidation cycle of ubiquinones in a model of mitochondrial electron transport systems.

O2- generation in mitochondrial electron transport systems, especially the NADPH-coenzyme Q10 oxidoreductase system, was examined using a model system, NADPH-coenzyme Q1-NADPH-dependent cytochrome P-450 reductase. One electron reduction of coenzyme Q1 produces coenzyme Q1-. and O2- during enzyme-catalyzed reduction and O2+ coenzyme Q1-. are in equilibrium with O2- + coenzyme Q1 in the presence of enough O2. The coenzyme Q1-. produced can be completely eliminated by superoxide dismutase, identical to bound coenzyme Q10 radical produced in a succinate/fumarate couple-KCN-submitochondrial system in the presence of O2. Superoxide dismutase promotes electron transfer from reduced enzyme to coenzyme Q1 by the rapid dismutation of O2- generated, thereby preventing the reduction of coenzyme Q1 by O2-. The enzymatic reduction of coenzyme Q1 to coenzyme Q1H2 via coenzyme Q1-. is smoothly achieved under anaerobic conditions. The rate of coenzyme Q1H2 autoxidation is extremely slow, i.e., second-order constant for [O2][coenzyme Q1H2] = 1.5 M-1.s-1 at 258 microM O2, pH 7.5 and 25 degrees C.

Anaerobiosis↗
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↗