A quantitative histochemical study of xanthine oxidase activity in rat liver using the cerium capture method in the presence of polyvinyl alcohol.

Abstract

(3A3155).A tecently developed histochemical technique to demonstrate xanthine oxidase activity in milk globules of bovine mammary gland and in epithelial cells of rat small intestine using cerium ions and a semipermeable membrane was slightly modified. The semipermeable membrane method was replaced by the addition of 10% (wh) polyvinyl alcohol to the incubation medium. This technically more simple procedure enabled detection of xanthine oxidase activity in unfmed cryostat sections of rat liver. Both methods gave qualitatively and quantitatively similar results. Activity was found in sinusoidal cells and in liver parenchymal cells, with 50% higher activity in pericentral than in periportal areas. The specificip of the reaaion was proven by the generation of only small amounts of fmal reaction product on incubation either in the absence of the substrates hypoxanthine or oxygen or in the presence of hypoxanthine and allopurinol. Allopurinol is a specific inhibitor of xanthine oxidase activity. The amount of final reaction product, as measured cytophotometrically in rat liver, increased linearly with incubation time (15-90 min) and with section thickness (up to 12 pm). By varying the hypoxanthine concentrations, a Km value of 0.05 mM was found. Addition of dithiothreitol to the incubation medium reduced the amount of final reaction product by 85%, which was caused by conversion of reversible xanthine oxidase into xanthine dehydrogenase. This histochemical method can be used for quantitative analysis of in situ xanthine oxidase activity. (]Hisrochem Cytochem 42:1091-1097, 1994)

NADH oxidation and superoxide production by caprine milk xanthine oxidoreductase

“…It is well-established that the XDH form of XOR is predominant in vivo (Brass, 1995;Fredericks, Bosh, Vanden Munckhof, & Van Noorden, 1995). This may fit well the markedly faster NADH oxidation, accompanied by O 2 dÀ production, observed with caprine and human milk XDH.…”

The role of xanthine oxidase in platelet activating factor induced intestinal injury in the rat

“…This method allows histological examination of the entire ileum. The histochemical localisation of XO was carried out as previously described 12. Briefly, 8 μm cryostat sections were incubated in incubation medium (100 mM Tris-maleate buffer, pH 8.0, containing 10 mM cerium chloride, 100 mM sodium azide, 0.5 mM hypoxanthine, and 10% polyvinyl alcohol) for 30 minutes at 37°C.…”

Ethanol-induced oxidative stress and acetaldehyde formation in rat mammary tissue: Potential factors involved in alcohol drinking promotion of breast cancer

“…Tissue blocks were stored at −80 • C until further use. Sections 8 m thick were cut on an International Cryostat IEC at −24 • C. The sections were picked up onto clean glass slides and incubated immediately for xanthine oxidase activity using the cerium capture method in the presence of polyvinyl alcohol described by Frederiks et al (1994). Briefly, the incubation mixture contained 100 mM Tris-maleate buffer, pH 8; 10 mM cerium chloride; 100 mM sodium azide; 0.5 mM hypoxanthine and 10% polyvinyl alcohol.…”