[Ultracytochemical demonstration of enzymes by reduction of potassium hexacyanoferrate (III). I. A method for demonstration of xanthine oxidase].

Xanthine oxidase is a flavoprotein which directly catalyses the oxidation of xanthine and hypoxanthine by oxygen or by potassium ferricyanide as an artificial acceptor of protons. In doing so, the potassium ferricyanide is reduced into potassium ferrocyanide which in the presence of manganese(II)ions leads to the manganese(II)ferrocyanide which is insoluble in water and in organic solvents. The latter is deposited on the areas with enzyme activity and marks them under the electron microscope.

Effect of cyclophosphamide on thyroid gland in mice and guinea pig.

Male BALB-/c mice and guinea pigs were given cyclophosphamide (CY)-either a single dose of 20 or 200 mg kg-1 or multiple doses of 2 or 20 mg kg-1 daily for 10 days. On the 1st, 3rd, 7th and 15th day after the last dose the serum levels of TSH, T4, T3 and rT3 were measured by RIA. The thyroids were processed for light and transmission electron microscopy.

Electron microscopic cytochemistry of adenylate cyclase in the ovarian compartments of ground squirrel during the annual cycle.

The ultrastructural localization and the activity changes of adenylate cyclase (AC) were studied in the ovarian compartments of sexually mature ground squirrels (Citellus citellus L.), during the both stages of hibernation (October to December and January to February), after awakening (March) and after gonadotropin (PMSG and HCG) intraperitoneal application during the both above mentioned stages. AC activity was found to be localized on the plasma membranes of theca interna, interstitial, and granulosa cells in ground squirrel ovary.