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Biomedical subjects

K Takeshige

Publications and source records attributed to K Takeshige.

At least 109 records · Page 6Linked to original sources
PubMed1987

Neutrophils become refractory to phorbol myristate acetate when treated with Ca2+-ionophore and Ca2+.

Human neutrophils deprived of divalent cations by treatment with ionophore A23187 in the presence of ethylene glycol bis(beta-aminoethylether)-N,N,N',N'-tetraacetic acid (EGTA) showed superoxide release when they were preincubated with calcium and then treated with the ionophore. The release was not observed when the ionophore was added first and then calcium was added more than 5 min later. The absence of the release in this case can be ascribed to a refractoriness of the cells to stimuli, because the cells did not release superoxide on stimulation with phorbol myristate acetate (PMA). The cells pretreated with either calcium or the ionophore alone did release superoxide on addition of PMA. The refractoriness of the cells to PMA depended on the concentrations of calcium and the ionophore and on the time interval between the two treatments. Calcium could be replaced with Cd2+ but not with Mg2+, Ba2+, or Sr2+. The release of granular enzymes was observed when the depleted cells were pretreated with the ionophore and then with calcium. These observations indicate that calcium has dual effects on the superoxide release of neutrophils, i.e., it stimulates the cells and makes them refractory to stimuli, depending on the time interval after the addition of the ionophore, and it also regulates the enzyme release by a different mechanism.

Aminoquinolines↗
PubMed1986

Inhibition of neutrophil superoxide formation by 1-(5-isoquinolinesulfonyl)-2-methylpiperazine (H-7), and inhibitor of protein kinase-C.

Superoxide formation of human neutrophils stimulated by phorbol 12-myristate 13-acetate (PMA), N-formyl-methionyl-leucyl-phenylalanine, or calcium ionophore A23187 was inhibited by pretreatment of the cells with 1-(5-isoquinolinesulfonyl)-2-methylpiperazine (H-7), an inhibitor of protein kinase-C, but was not inhibited by N-(2-guanidinoethyl)-5-isoquinolinesulfonamide which has a less inhibitory effect on the protein kinase-C. H-7 also inhibited superoxide formation of PMA-activated cytoplasts, which lack nuclei and granules. The phosphorylation of proteins induced by PMA in the cytoplasts as well as the intact neutrophils was also inhibited by preincubation with H-7. Among several phosphoproteins affected by H-7, one protein with a molecular weight of 19,000 (pI = 4.9) was inhibited markedly. N-(2-Guanidinoethyl)-5-isoquinolinesulfonamide did not inhibit the phosphorylation of proteins induced by PMA. These findings support the possibility that the protein kinase-C is involved in the activation process of superoxide formation.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed1986

Calcium channel antagonist induced inhibition of superoxide production in human neutrophils. Mechanisms independent of antagonizing calcium influx.

Three calcium channel antagonists, verapamil, diltiazem and nisoldipine, inhibited superoxide production in human neutrophils that were stimulated by phorbol 12-myristate 13-acetate (PMA) in a buffered saline lacking calcium. Concentrations of these drugs giving 50% control activity (IC50) were 0.3, 0.45 and 0.01 mM respectively. This inhibition was also observed in the presence of ethylene glycol bis (beta-aminoethyl ether)-N,N'-tetraacetic acid (EGTA) and was not reversed by the addition of calcium. This suggests that calcium channel antagonists inhibited superoxide production independently of extracellular calcium. These calcium channel antagonists inhibited the mobilization of membrane-associated calcium, and protein phosphorylation probably catalyzed by C-kinase, both of which are thought to be involved in the signal transmission for the induction of superoxide production. Calcium channel antagonists also inhibited NADPH oxidase, responsible for superoxide production, with IC50 = 0.5, 3 and more than 0.08 mM, respectively, for verapamil, diltiazem and nisoldipine. The results indicate that calcium channel antagonists inhibit superoxide production by affecting not only the catalytic activity by also the activation of NADPH oxidase. Inhibition of superoxide production by calcium channel antagonists suggests that these antagonists do not affect cell functions merely by affecting calcium influx.

Calcium↗
PubMed1986

NADPH binding component of neutrophil superoxide-generating oxidase.

The 2',3'-dialdehyde derivative of NADPH was used as an affinity labeling reagent of a solubilized NADPH-dependent superoxide-generating oxidase preparation of pig neutrophils. The analogue served as both an electron donor and a competitive inhibitor of the NADPH oxidase against NADPH. The apparent Michaelis constant (Km) for the derivative (31 microM) was essentially the same as that for NADPH (33 microM). The activity of the superoxide formation in the presence of 2',3'-dialdehyde NADPH was about a half of that in the presence of NADPH. Incubation of the enzyme with the derivative inactivated the superoxide-generating activity and the inactivation was prevented by the addition of NADPH. We performed the labeling of the oxidase preparation with 2',3'-dialdehyde NADPH and sodium cyanoboro[3H]hydride, based on the above results. A protein of 66,000 daltons was selectively labeled among more than 20 bands in sodium dodecyl sulfate-polyacrylamide gel electrophoresis which were visualized with Coomassie Brilliant Blue. The protein was not labeled when the oxidase preparation was pretreated with p-chloromercuribenzoate or it was labeled in the presence of excess NADPH. The protein is suggested to be the NADPH binding component of the neutrophil superoxide-generating oxidase system.

Affinity Labels↗
PubMed1986

A simultaneous quantitation of leukotriene B4 and its omega-oxidized products by gas chromatography-mass spectrometry.

We developed a highly sensitive and specific method for the simultaneous quantitation of leukotriene B4 (LTB4) and its omega-oxidized metabolites (20-hydroxy-LTB4 and 20-carboxy-LTB4) by mass fragmentography using deuterated compounds as internal standards. The ions produced by the cleavage of the C12-13 bond of the methyl ester dimethylisopropylsilyl ether derivatives of LTB4 and its metabolites were measured by selective ion monitorings. The detection limit of LTB4 was less than 10 pg and about 100-fold lower than that by high performance liquid chromatography. By using this method, the synthesis and further metabolism of LTB4 in human polymorphonuclear leukocytes were investigated.

Gas Chromatography-Mass Spectrometry↗
PubMed1986

Protein phosphorylation of neutrophils from normal children and patients with chronic granulomatous disease.

The phosphorylation and dephosphorylation of proteins in neutrophils from normal children and patients with chronic granulomatous disease (CGD) were studied with two-dimensional gel electrophoresis and autoradiography, followed by densitometric scanning. In normal neutrophils the radioactivities of 11 spots among approximately 50 radioactive spots were changed by stimulation with phorbol 12-myristate 13-acetate (PMA) and 6 of the 11 spots were also changed by stimulation with N-formyl-methionyl-leucyl-phenylalanine (FMLP) and NaF. The phosphorylation of only two spots (Mr = 48 000 and 62 000) was inhibited by 2-deoxyglucose and N-(6-aminohexyl)-5-chloro-1-naphthalene sulphonamide (W-7), which inhibits superoxide production, while it was not affected by dibutyryl cAMP, KCN and ethyleneglycol-bis-(beta-aminoethylether)-N,N'-tetraacetic acid (EGTA), which do not affect superoxide production. The observation indicates that the Mr = 48 000 and 62 000 proteins may be involved in the activation process of superoxide production. When the neutrophils of four male and two female CGD patients were examined, the changes in 11 spots on stimulation were similar to those of normal children, indicating that the (de)phosphorylation of the proteins which seems to be involved in the activation process is not affected in CGD neutrophils.

Autoradiography↗
PubMed1986

Cinchocaine and amethocaine inhibit activation and activity of superoxide production in human neutrophils.

Local anaesthetics, cinchocaine and amethocaine, inhibited superoxide production in human neutrophils stimulated by phorbol ester, with IC50 (concentration of a drug giving 50% activity of control) values of 0.2 and 0.6 mmol litre-1, respectively. These anaesthetics inhibited protein (de)phosphorylation and mobilization of membrane-associated calcium, both of which are probable signal transmission mechanisms for the induction of superoxide production. Local anaesthetics also inhibited NADPH oxidase, responsible for superoxide production, with IC50 = 0.3 and 0.9 mmol litre-1, respectively. The results indicate that cinchocaine and amethocaine inhibit superoxide production in human neutrophils by affecting not only the catalytic activity, but also the activation, of NADPH oxidase.

Blood Proteins↗
PubMed1986

Spontaneous induction of superoxide release and degranulation of neutrophils in isotonic potassium medium: the role of intracellular calcium.

When guinea pig peritoneal neutrophils were suspended in the isotonic medium of potassium, rubidium, and cesium ions at 37 degrees C, the cells released superoxide, while low activity was observed in the isotonic medium of sodium and lithium ions. The activity induced in the potassium medium was enhanced by potassium-ionophores, valinomycin, and gramicidin, and decreased by a potassium channel blocker, 4-aminopyridine. The superoxide-releasing activity was not affected by the presence or absence of extracellular calcium but was inhibited by an intracellular calcium antagonist-8-(N,N-diethylamino)-octyl-3,4,5-trimethoxybenzoate(TMB-8) with the half-inhibition concentration of 50 microM. The release of granular enzymes, lysozyme and beta-glucuronidase, was also induced in the isotonic potassium medium in the absence of extracellular calcium and inhibited by TMB-8. A remarkable elevation of the intracellular free calcium concentration in neutrophils, which was monitored by quin-2 fluorescence, was found when the cells were added to the potassium medium without calcium. The elevation was inhibited by the addition of TMB-8. These observations suggest that calcium mobilization from intracellular storage sites, not an influx of calcium from the extracellular medium, causes the release of superoxide and the granular enzymes in isotonic potassium medium.

Animals↗
PubMed1986

NADPH-dependent superoxide-forming oxidase in phagocytic vesicles of human monocytes.

Phagocytic vesicles with superoxide-forming NADPH oxidase activity were obtained from human monocytes phagocytosing oil droplets. The superoxide-forming activity in the monocyte vesicles increased for the first 5 min during incubation with oil droplets and remained constant for 30 min. NADPH-dependent activities of 2,6-dichlorophenol-indophenol (DCIP) reduction and ubiquinone-1 (Q1) reduction were found in the vesicles and the activities were closely associated with the superoxide-forming oxidase. The values of apparent Km for NADPH of these three activities were essentially the same and the activities were inhibited with a similar pattern by p-chloromercuribenzoate and a cationic detergent, cetyltrimethylammonium bromide. The activities were extremely labile and the DCIP reductase activity was most labile. The superoxide-forming oxidase and the Q1 reductase could be extracted with a mixture of deoxycholate and Tween-20. The extracted activities were not enhanced by the addition of FAD.

2,6-Dichloroindophenol↗
PubMed1986

Inhibition of superoxide production and Ca2+ mobilization in human neutrophils by halothane, enflurane, and isoflurane.

The inhibitory effects of three inhalation anesthetics, i.e., halothane, enflurane, and isoflurane, on superoxide production and the intracellular mobilization of calcium in human neutrophils were studied. The superoxide production induced by N-formyl-methionyl-leucyl-phenylalanine (FMLP) was inhibited by the anesthetics, but the binding of FML[3H]P to the cells and the superoxide-forming NADPH oxidase of the phagocytic vesicles were not inhibited. The inhibition of the cellular superoxide production was partially reversed by the addition of a calcium ionophore, A23187. The increase in intracellular free calcium monitored by a calcium-sensitive fluorescent probe, quin-2 and the release of calcium from hydrophobic environment monitored by chlortetracycline were inhibited dose dependently by the anesthetics. These observations suggest that decreased mobilization of intracellular Ca2+ is one of the mechanisms by which the anesthetics inhibited the superoxide production of human neutrophils stimulated by FMLP.

Calcimycin↗
PubMed1986

[An analysis of prognostic examination in cirrhotic portal hypertension and hepatoma].

With an increasing number of patients with advanced liver cirrhosis, the discrepancy between the preoperative examination and results of surgery for bleeding varices is widening. To correct this discrepancy, additional prognostic examinations to Child's criteria and routine hepatic laboratory tests were studied in our 246 cirrhotic patients with esophageal varices. These included wedged hepatic vein pressure, clearance and maximal removal rate of indocyanine green, and hepaplastin test. We performed the endoscope assisted terminal esophagoproximal gastrectomy with the EEA stapler gun with devascularization and splenectomy. No operative death and complications developed when the results of following 4 preoperative examinations were: wedged hepatic vein pressure below 400 mm of saline, peripheral disappearance rate (K) of indocyanine green above 0.04 min-1, maximal removal rate (Rmax) of the dye above 0.3mg/kg/min and hepaplastin test more than 40%. It is necessary for these indicators to be satisfied simultaneously prior to performing this surgery. In addition, these values should be changed a little in their critical limits when these cirrhotic patients also had hepatoma and were candidates for hepatectomy.

Adult↗
PubMed1985

NAD+-dependent conversion of 20-OH-LTB4 to 20-COOH-LTB4 by a cell-free system of human polymorphonuclear leukocytes.

Human polymorphonuclear leukocytes, but not mononuclear leukocytes, platelets, or erythrocytes, oxidized 20-hydroxy-leukotriene B4 (20-OH-LTB4) to 20-carboxy-LTB4 (20-COOH-LTB4). 20-OH-LTB4 was quantitatively converted to 20-COOH-LTB4 by the sonicate of polymorphonuclear leukocytes in the presence of NAD+, with an optimal pH of about 7.9. NADP+ could not replace NAD+. The conversion was not inhibited by 2 mM pyrazole, a potent inhibitor of alcohol dehydrogenase. When LTB4 was incubated with the sonicate in the presence of NADPH and NAD+, 20-OH-LTB4 and 20-COOH-LTB4 appeared concomitantly with the disappearance of LTB4.

Cell-Free System↗
PubMed1985

Pertussis toxin inhibits intracellular pH changes in human neutrophils stimulated by N-formyl-methionyl-leucyl-phenylalanine.

Changes of intracellular pH in human neutrophils were monitored by 9-aminoacridine fluorescence. Both initial acidification and subsequent alkalinization phases induced by a chemotactic peptide, N-formyl-methionyl-leucyl-phenylalanine were dependent on the extracellular Ca2+-concentrations, and a calcium ionophore, A-23187 similarly induced the pH-changes. Pertussis toxin inhibited the pH-changes induced by the peptide while cholera toxin did not. The pH-changes induced by A-23187 were not affected by the toxins. The results suggest that the inhibitory guanine-nucleotide regulatory protein and Ca2+ are involved in the pH-changes induced by the peptide.

Adult↗
PubMed1985

The role of Ca2+ and Ca2+-activated phospholipid-dependent protein kinase in degranulation of human neutrophils.

The degranulation reactions of human neutrophils induced by 1-oleoyl-2-acetylglycerol (OAG), phorbol 12-myristate 13-acetate (PMA), and calcium ionophore A23187 or their combinations, were studied. OAG in the absence of the Ca2+-ionophore A23187 stimulated the releases of both lysozyme and lactoferrin, constituents of the specific granules, but did not stimulate the release of beta-glucuronidase, an enzyme of the azurophil granules. Electron microscopy revealed a selective decrease in the numbers of the specific granules in this case. The combined effects of A23187 at a concentration higher than 0.1 microM and OAG were essentially additive. W-7, known to be an inhibitor of both Ca2+-activated phospholipid-dependent protein kinase (C-kinase) and calmodulin, inhibited the degranulation induced by OAG or PMA, while it inhibited the reaction induced by A23187 less markedly. The release of lysozyme reached a plateau at about 0.1 microM A23187 and increased again at higher concentrations of A23187. The observations suggest that degranulation can be induced by the activation of the C-kinase, and the degranulation by A23187 at low concentrations may be due to the activation of the C-kinase; the effects of A23187 at high concentrations, however, could not be explained only in terms of the activation of the C-kinase.

Bucladesine↗
PubMed1984

A cell-free preparation of human neutrophils catalyzing NADPH-dependent conversion of leukotriene B4.

The sonicate of human neutrophils converted leukotriene B4 to a polar product in aerobic condition in the presence of NADPH at a rate comparable to that of the intact cells. NADH could scarcely replace NADPH. The conversion was not observed in anaerobic conditions and was inhibited by carbon monoxide (CO/O2 = 4/1) or by 1 mM p-chlormercuribenzoate, while it was not affected by 1 mM KCN, 5 mM NaN3, 200 micrograms/ml catalase, 100 mM mannitol, and 10 micrograms/ml superoxide dismutase. These observations suggest that the myeloperoxidase-H2O2-halide system and active oxygen species are not involved in the reaction. The activity was observed in the 100,000xg supernatant from the homogenate, in which cytochrome P-450 was not detected.

Humans↗
PubMed1984

Protein phosphorylation in intact pig leukocytes.

The phosphorylation of proteins in intact pig polymorphonuclear leukocytes loaded with H3(32)PO4 was investigated by two-dimensional gel electrophoresis and subsequent autoradiography. The incorporation of 32P into at least 17 proteins began to increase and into one to decrease, relative to resting cells, upon exposure of the cells to phorbol 12-myristate 13-acetate. These changes in the autoradiographic patterns were accompanied by changes in the protein patterns obtained by staining with Coomassie brilliant blue, including the appearance, the acidic shift and the increase or decrease of the intensity of the spots. Among these proteins, Mr = 64 000, 31 000, 22 000, 21 000, 18 000 and 13 000 proteins were correlated well with the superoxide anion production of the cells in respect to the time-courses and the dose-responses. By taking the effects of EGTA into consideration, the phosphorylation of Mr 64 000 and 21 000 proteins, of which the latter was identified as the light chain of myosin, seemed to be involved in the signal-transmission mechanism of the induction of the NADPH oxidase responsible for the 'respiratory burst'. These two proteins were also phosphorylated in the cells stimulated by NaF or oil droplets opsonized with IgG.

Animals↗
PubMed1984

Superoxide release and intracellular free calcium of calcium-depleted human neutrophils stimulated by N-formyl-methionyl-leucyl-phenylalanine.

The superoxide release and the change in the intracellular free calcium ions on stimulation with N-formyl-methionyl-leucyl-phenylalanine were studied in human neutrophils deprived of divalent cations by treatment of the cells with ionophore A23187 in the presence of EGTA. The depleted cells showed no release of superoxide on stimulation with the chemotactic peptide when calcium ions were absent in the medium, but the activity was completely recovered when the cells were preincubated with calcium for at least 3 min before the stimulation. The cells pretreated with Cd2+ showed slight activity of the release, but no recovery was observed with other divalent cations such as Mg2+, Sr2+, Co2+, Ba2+ and Zn2+. The recovery with calcium ions was dependent on the time of the addition relative to the time of the stimulation with the chemotactic peptide: a simultaneous addition of both calcium and the peptide elicited about half of the full activity, while no release was observed when calcium was added later than 2 min after the stimulation with the peptide, though a marked elevation of the intracellular free calcium monitored by quin-2 fluorescence was found. Comparison of the time-courses of the superoxide release and the change in the fluorescence suggest that, besides the elevation of intracellular free calcium, a transient reaction which is also dependent on calcium is required for the full induction of the superoxide-producing activity.

Aminoquinolines↗