Potentiation of histamine and inhibition of diamine oxidase by mescaline

Zusammenfassung Anhand zweier Versuchsanordnungen wird gezeigt, dass Meskalin Histaminwirkungen verstärken kann. Ausserdem vermag es die Histamin zerstörende Wirkung der Diaminooxydase zu hemmen (in 10^–5-molarer Konzentration).Es wird die Möglichkeit diskutiert, dass diese Eigenschaften mit der 4-Methoxyphenyl-äthylamin-Struktur des Meskalins in Zusammenhang stehen könnten.     

Oxidation of vanillin by cream xanthine oxidase and its inhibition by allopurinol

Zusammenfassung Es wird gezeigt, dass Vanillin durch Xanthinoxydase oxydiert und dass diese Reaktion durch Allopurinol gehemmt wird.     

Potentiation of cutaneous inhibition by alcohol

Résumé Les effets de l'alcool éthylique sur l'inhibition présynaptique dans le Noyau de Burdach furent étudiés. Il apparut que ce produit intensifie l'accroissement en excitabilité des extrémités afférentes cunéaires et l'inhibition de la réaction lemnisque, ceci en conditionnant les décharges cutanées. L'alcool augmente aussi l'intensité de l'onde de surface positive. En conclusion, l'alcool intensifie l'inhibition présynaptique du stimulus cutané au niveau du Noyau de Burdach.     

Inhibition of xanthine oxidase by liquiritigenin and isoliquiritigenin isolated from Sinofranchetia chinensis

The methanol extract of the stem of Sinofranchetia inhibited the activity of xanthine oxidase in vitro. Bioassay-guided purification led to the isolation ofliquiritigenin and isoliquiritigenin as the main xanthine oxidase inhibitors. This inhibition of enzyme activity was found to be dose dependent, with an IC50 value of approximately 49.3 microM for liquiritigenin and 55.8 microM for isoliquiritigenin. Lineweaver-Burk transformation of the inhibition data indicated that the inhibition was of a mixed type for both liquiritigenin and isoliquiritigenin. For liquiritigenin, the Ki and K(I) were determined to be 14.0 microM and 151.6 microM, respectively. For isoliquiritigenin, the Ki and K(I) were determined to be 17.4 microM and 81.9 microM, respectively. These results suggest that these natural products could be used to treat conditions where the inhibition of xanthine oxidase is warranted.     

The effect of phosphate on cream xanthine oxidase

Zusammenfassung Die Einwirkung von Orthophosphat auf die Milch-Xanthinoxydase wurde unter verschiedenen experimentellen Bedingungen untersucht. Phosphat hemmt einerseits die Übertragung des mobilisierten Wasserstoffes auf 2,6-Dichlorophenol-indophenol mit frischen Enzym-Präparaten und aktiviert andrerseits die Akzeptorfunktion des Sauerstoffes bei gealterten, oder anderweitig inaktivierten Präparaten.     

Effect of the administration of xanthine on the appearance of xanthine oxidase activity in the liver of growing rats

Riassunto La somministrazione di xantina a ratti di età compresa fra i 12 e i 30 giorni, causa una precoce comparsa di attività xantinossidasica. Tale comparsa è influenzata dalla cycloheximide ma non dal cortisone nè dalla attinomicina D.     

Elevation of serum xanthine oxidase following halothane anesthesia in the rat

Summary Halothane anesthesia was found to be hepatotoxic in the rat, as demonstrated by a significant elevation of serum xanthine oxidase (SXO) level. SXO appeared to be a more sensitive marker of liver damage than serum, glutamic oxalacetic transaminsa. SXO was found to be elevated also following exposure to relative hypoxia.     

Effect of hepatocarcinogens on rat serumpara-phenylene diamine oxidase and xanthine dehydrogenase

Résumé On a observé une diminution de lapara-phénylène-diamine-oxydase et parfois une augmentation de la xanthine déhydrogenase dans le sérum sanguin des rats traités avec quelques substances cancérigènes pour le foie.     

Elevation of serum xanthine oxidase following halothane anesthesia in the rat.

Halothan anesthesia was found to be hapatotoxic in the rat, as demonstrated by a significant elevation of serum xanthine oxidase (SXO) level. SXO appeared to be more sensitive marker of liver damage than serum glutamic oxalacetic transaminase. SXO was found to be elevated also following exposure to relative hypoxia.     

Serum para-phenylenediamine oxidase and xanthine dehydrogenase levels during liver carcinogenesis in the rat

Zusammenfassung Werden Ratten mit dem carcinogenen 3-Methyl-4-dimethylaminoazobenzol gefüttert, so nimmt die Konzentration der p-Phenylendiaminoxidase im Serum anfangs rasch ab, um am Ende der Fütterungsperiode langsam wieder auf den Normalwert anzusteigen.Eine Verminderung der Xanthindehydrogenase des Serums war nur zu Beginn des Wachstums von Lebertumoren zu beobachten. Mit Azofarbstoffen gefütterte Ratten wurden anämisch.     

Monoamine oxidase inhibition by d-amphetamine in ganglia and nerve endings

Summary The inhibition of monoamine oxidase (MAO) activity by d-amphetamine was measured in homogenates of cat superior cervical ganglion and nictitating membrane, using tyramine (TM) and noradrenaline (NA) as substrates. In both tissues, d-amphetamine was shown to be a competitive inhibitor of the oxidation of TM. The Ki for d-amphetamine, as a MAO inhibitor, was lower in the ganglia than in the peripheral nerve endings.Supported by a Contract from the National Research Council of Argentina (CONICET) (Res. 67/79).     

Towards specific NADPH oxidase inhibition by small synthetic peptides

Reactive oxygen species (ROS) production by the phagocyte NADPH oxidase is essential for host defenses against pathogens. ROS are very reactive with biological molecules such as lipids, proteins and DNA, potentially resulting in cell dysfunction and tissue insult. Excessive NADPH oxidase activation and ROS overproduction are believed to participate in disorders such as joint, lung, vascular and intestinal inflammation. NADPH oxidase is a complex enzyme composed of six proteins: gp91phox (renamed NOX2), p22phox, p47phox, p67phox, p40phox and Rac1/2. Inhibitors of this enzyme could be beneficial, by limiting ROS production and inappropriate inflammation. A few small non-peptide inhibitors of NADPH oxidase are currently used to inhibit ROS production, but they lack specificity as they inhibit NADPH oxidase homologues or other unrelated enzymes. Peptide inhibitors that target a specific sequence of NADPH oxidase components could be more specific than small molecules. Here we review peptide-based inhibitors, with particular focus on a molecule derived from gp91phox/NOX2 and p47phox, and discuss their possible use as specific phagocyte NADPH oxidase inhibitors.     

Elevation of serum xanthine oxidase activity following halothane anesthesia in man

Summary Halothane, but not methoxyflurane, was found to cause specific hepatocellular damage, the hepatotoxicity being prompt but transient. The hepatotoxicity was demonstrated by the elevation in the serum activity of xanthine oxidase, a highly sensitive marker for acute liver damage.     

Assessment of the scavenging action of reduced glutathione, (+)-cyanidanol-3 and ethanol by the chemiluminescent response of the xanthine oxidase reaction

The free radical scavenging capacity of reduced glutathione (GSH), (+)-cyanidanol-3 and ethanol was assessed by their interference with the maximal chemiluminescent response produced by the xanthine oxidase reaction. GSH and (+)-cyanidanol-3 induce a progressive inhibition of chemiluminescence when increasing amounts are added to the reaction mixture. GSH and (+)-cyanidanol-3 added together at low concentrations (1 and 0.05 mM respectively) exhibit an additive effect. The addition of ethanol presents a biphasic effect. It inhibits chemiluminescence at low concentrations (10-50 mM) while at higher concentrations (75-500 mM) this effect is reversed. Estimation of the concentrations required to produce half of the maximal inhibition of chemiluminescence by these agents revealed that ethanol is less effective than GSH and (+)-cyanidanol-3 as a free radical scavenger in the system used.