Effect of ACTH on the zona reticularis of the rat adrenal cortex: An ultrastructural stereologic study

Summary The effects of ACTH on the rat adrenalzona reticularis were investigated by stereologic methods. It was found that thezona reticularis cell responsiveness to ACTH is similar to that of thezona fasciculata elements. This excludes that thezona reticularis of the adult rat can only function as the site of destruction of worn-out elements migrating from the adrenal outer zones.Acknowledgment. We wish to thank Mr.G. Gottardo for his skilled technical assistance. This work was partly supported by a contract with the CNR No. C.T.73.00663.04.     

Effects and duration of resistance acquired by rabbits on feeding and egg laying in Ixodes ricinus L.

Rabbits gradually developed a resistance against Ixodes ricinus ticks as a result of sequential experimental infestations. The resistance was characterized by an increase duration of feeding, by ticks engorging to a smaller extent and by reduced egg production. Once established, the immunity persisted for at least 9 months. Changes in the titre of circulating anti-I. ricinus antibodies was measured by indirect immunofluorescence.     

Untersuchungen zur Organotropie der krebserzeugenden Wirkung des N-Nitroso-N-methyl-Harnstoffes (NMH) an Ratten

Summary Methyl-nitrosourea, an unstable nitrosamide, exhibits a resorptive cancerogenic effect after shorttermed oral administration of high doses (4 times 40 mg/kg body weight). Induction time and localization of the observed tumours depend, among other things, on the dose and the pH of the cancerogen solution and on the age of animals.