Leon Weiss

CYTOCHEMICAL OBSERVATIONS ON CHICKEN MONOCYTES MACROPHAGES AND GIANT CELLS IN TISSUE CULTURE

Cultures of leukocytes from chicken blood grown in fluid medium in roller flasks were stained for lipids, carbohydrates, phosphatase, esterase, and succinic dehydrogenase in order to study the cytochemical changes associated with the transformation of monocytes to macrophages, epithelioid cells and multinucleate giant cells. The great variability in cell form observed by previous investigators in such cultures was confirmed. The cells were usually round but not uncommonly were stellate or fusiform, sometimes bearing a striking similarity to fibroblasts, at other times resembling sheets of mesothelium. The factors determining their size and shape were obscure, but low pH seemed to favor the formation of giant cells. Monocytes of chicken blood were ordinarily devoid of stainable lipid, carbohydrate and enzymes. Macrophages and epithelioid cells which developed from them were negative for esterase, succinic dehydrogenase and alkaline phosphatase but gave a strong reaction for acid phosphatase, localized in their enlarged centrosphere or Golgi zone. This region also contained a saliva-resistant, periodic acid-Schiff positive material, probably a carbohydrate-protein complex and its relation to the enzyme acid phosphatase has been considered. Numerous small lipid droplets were disposed around the periphery of the Golgi zone. Giant cells occasionally contained glycogen. The acquisition of acid phosphatase by monocytes during their transformation to macrophages appeared to be related to their enhanced phagocytic activity.

Histochemical demonstration of protein-bound amino groups.

A method for the histochemical demonstration of protein-bound amino groups is described. The method is based upon the reaction of primary amino groups with aldehydes to form Schiff bases. By the use of 3-hydroxy-2-naphthaldehyde, a red to blue azo dye is formed at the sites of reactivity in fixed tissue sections, after coupling with tetrazotized diorthoanisidine. Preparations of the reagent, histochemical procedure, evidence for the specificity of the reaction and the results of its application to normal rat tissues are given.

ADRENAL LUTEINIZING HORMONE RELEASING HORMONE RECEPTORS

Paraffin sections of mouse adrenals processed with antiserum to luteinizing hormone-releasing hormone (LHRH) in the unlabeled antibody enzyme method reveal moderate staining in the cytoplasm of cells of zona fasciculata and reticularis. The stain is intensified upon pretreatment of sections with LHRH. Pretreated sections processed with solid phase immunoabsorbed LHRH are unstained. Analogues of LHRH deficient in the C-terminal glycine amide inhibit staining, while analogues deficient in the N-terminal pyroglutamic acid have no effect. It is concluded that the adrenal contains receptors for a ligand resembling LHRH in receptor and immunoreactivity. The possibility is considered that the ligand may be an inhibitor of pineal origin.

ASPECTS OF THE RETICULOENDOTHELIAL SYSTEM STUDIED WITH THE LIGHT MICROSCOPE AND THE ELECTRON MICROSCOPE

The reticuloendothelial system, first clearly demonstrated by Goldmann (19091, is a system of connective tissue cells through which are expressed whatever potentialities for cellular differentiation persist from mesenchyme. It has been recognized as comprised of cells concentrated in hematopoietic and endocrine tissues and fixed to a fibrous extracellular reticulum, and of cells free of reticulum and dispersed through almost every connective tissue (Maximow, 1924). Flattened as endothelium, it may make up the walls of sinuses or, in stellate form, may constitute less well-organized parts of reticular tissue. In either case the reticular cell remains a multipotent connective tissue cell capable of differentiating into any of the blood cells, into macrophages, fibroblasts, and fat cells and, possibly, into other connective tissue cell types. Cytologically, reticular cells are undifferentiated, having large spherical nuclei and pale extensive cytoplasm. They lack even the compacted basophilic cytoplasm, conspicuous nucleoli, and prominent nuclear membranes that signify the synthesis of protein and that, in fact, constitute in primitive blood cells the first evidence of differentiation from reticular cells. Fixed cells may become free of the reticulum. Such detachment may actually represent cellular maturation and may restrict the subsequent capacities of these cells for differentiation. Indeed, the capacities for transformation of the free cells of the reticuloendothelial system have been the source of extended controversy. Histiocytes (and monocytes that may evolve into histiocytes) are clearly phagocytic and may elaborate adaptive enzymes. There is, moreover, increasing acceptance of the unitarian view that these cells and lymphocytes are but minor variants of the same multipotential cell type. In this presentation I shall consider certain aspects of the reticuloendothelial system that have particular reference to this monograph, and not attempt a systematic treatment. I propose to discuss the sinuses in the red pulp of the spleen of rats, the relationship of splenic cords to splenic sinuses, the nature of the reticulum, a cytoplasmic inclusion induced in reticuloendothelial cells of guinea pigs by estrogens, the FOB-Kurloff body and, finally, techniques for the study of the dermal bone of the nine-banded armadillo. My discussion will be primarily morphologic, based upon observations with both the light and the electron microscopes.

Adrenal Luteinizing Hormone Releasing Hormone Receptors

Paraffin sections of mouse adrenals processed with antiserum to luteinizing hormone-releasing hormone (LHRH) in the unlabeled antibody enzyme method reveal moderate staining in the cytoplasm of cells of zona fasciculata and reticularis. The stain is intensified upon pretreatment of sections with LHRH. Pretreated sections processed with solid phase immunoabsorbed LHRH are unstained. Analogues of LHRH deficient in the C-terminal glycine amide inhibit staining, while analogues deficient in the N-terminal pyroglutamic acid have no effect. It is concluded that the adrenal contains receptors for a ligand resembling LHRH in receptor and immunoreactivity. The possibility is considered that the ligand may be an inhibitor of pineal origin.