Alexei A. Koneff

Adaptation of the Mallory-Azan Staining Method to the Anterior Pituitary of the Rat

A staining procedure by modification of the “Mallory-azan” method, as adapted to the anterior pituitary of the rat, is described. No claim is made that the fundamental principle of the procedure is new; but because it invariably differentiates sharply the three classical cell types it is felt that the technic should be published. Pituitaries are fixed in Zenker-formol solution, embedded in nitrocellulose and cut at 3-4 μ. Sections are affixed to the slides, prior to the staining procedure, with the aid of albumin-glycerin, and nitrocellulose is removed with oil of cloves. After the sections are properly stained with azocarmine and treated with 5% phosphotungstic acid, as a separate step, they are stained with Mallorys anilinblue-orange-G mixture.1 It was, however, found advantageous not to omit oxalic acid and to decrease considerably the amount of phosphotungstic acid given in the formula. After the staining in this solution is completed, sections are again treated with 5% phosphotungstic acid, followed...

Hypothalamic Control of Pituitary Function and Corpus Luteum Formation in the Rat.

Summary and Conclusions 1. Bilateral hypothalamic lesions ventral to the ventro-medial nucleus in female rats resulted in persistent vaginal cornification in the majority of animals. Thyroid morphology and I131 uptake in obese rats with constant cornification indicated increased thyroid activity. The ovaries of those showing constant cornification contained follicles of all sizes but no corpora lutea. The interstitial tissue was not atrophic. 2. The follicles were readily converted into corpora lutea by administration of luteinizing substances, both human chorionic gonadotrophin and pituitary interstitial cell stimulating hormone. The interpretation is made that secretion of luteinizing factor by the pituitary may be impaired by small, bilateral hypothalamic lesions ventral to the ventro-medial nucleus.

Pheochromocytomas of adrenals in male rats chronically injected with pituitary growth hormone.

Summary The long term administration of pituitary growth hormone to adult male rats of the Long-Evans strain resulted in progressive growth in body weight and length. Many neoplasms developed in the rats during this prolonged period, but the incidence in treated rats was not significantly different from that in controls, with the exception of tumors of the adrenal medulla. Pheochromo-cytomas occurred in 9 of 16 growth hormone injected rats and in none of the controls.

Rapid Embedding with Hot Low-Viscosity Nitrocellulose

A rapid method for embedding with low-viscosity nitrocellulose is described. Advantage is taken of the greater penetrating power of low-viscosity nitrocellulose than that of common varieties of celloidin. Fixation, dehydration and infiltration are carried out in screw-topped jars in the incubator at 56° C. The whole procedure from fixing to sectioning can be finished in 15-30 hours, and sections as thin as 6 to 10 μ may be cut without difficulty.