Cell types of the pars distalis of the hedgehog (Erinaceus europaeus L.) adenohypophysis: cytological, immunocytochemical and ultrastructural studies. 2. Prolactin cells

Staining and histochemical methods, immunofluorescence, and electron microscopy were used to individualize the prolactin cells in the adenohypophyseal pars distalis of the nonhibernating hedgehog. One cell type was differentiated; their characteristics at the light and electron microscopic levels were presented. Immunofluorescence has confirmed the functional significance of this cell type and the validity of the denomination 'prolactin cells'.     

Cell types of the pars distalis of the hedgehog (Erinaceus europaeus L.) adenohypophysis: cytological, immunocytochemical and ultrastructural studies. 4. Thyrotropic cells

Staining and histochemical methods, immunofluorescence and electron microscopy were used to individualize the thyrotropic cells in the adenohypophysis of the non-hibernating hedgehog. One cell type was differentiated; its characteristics at the light and electron-microscopic levels were presented. Immunofluorescence has confirmed the functional significance of this cell type and the validity of the denomination of 'thyrotropic cells'.     

First divisions of somatic embryogenic cells inCichorium hybrid “474”

Summary First divisions of embryogenic cells were studied in leaves of plantlets of aCichorium hybrid (C. intybus L. ×C. endivia L.) cultured in vitro in a liquid agitated medium, at 35 °C in the dark. Stages of reactivation of competent cells were characterized by increase of nucleus and nucleolus diameter, migration of the nucleus in the centre of the cell and thickening of the cell wall. The first division of reactivated embryogenic cells was symmetrical and anticlinal in regard to the xylem vessels orientation. Embryogenic structures consisted in I-type tetrads or in rows of 4–8 cells. Then the divisions occurred in thickness at one end, without polarization or formation of a suspensor-like structure.Abbreviations EC embryogenic cell - ES embryogenic structure     

Integumentary resorption and collagen synthesis during regression of headless pedicellariae in Sphaerechinus granularis (Echinodermata: Echinoidea)

Ultrastructure of the resorption of integumentary tissues (ligaments, muscles, fibrous tissue, nerves, and skeleton) and the synthesis of collagen is described for the first time in echinoderms. Resorption is cell-mediated. Phagocytic cells are characterized by Golgi-derived putative primary lysosomes. Numerous secondary lysosomes and residual bodies occur in the bodies and processes of phagocytic cells. They engulf whole muscle cells and nerve fibres, as well as collagen fibril segments that exceed 1.5 m in length. Skeletoclastic cells resemble vertebrate osteoclasts, showing a ruffled border, lysosomes, and numerous mitochondria. They surround trabeculae with thick processes to delimit a tubular resorption site. Collagen synthesis occurs in the space formerly occupied by resorbed tissues. Synthesis is performed by fibroblastic cells containing organelles typical of vertebrate fibroblasts, namely distended cisternae of rough endoplasmic reticulum, Golgi cisternae with distended edges, and procollagen granules. Procollagen granules are apparently exocytosed directly to the extracellular matrix. Evidence indicates that resorbing (phagocytic and skeletoclastic) cells and fibroblastic cells may belong to a common phagocyte lineage. These cells share the ability to form elaborate processes and to become syncytial, and their nuclei exhibit iron-containing crystals.This project was supported by Contract 2.4527.89 from the Fonds de la Recherche Fondamentale Collective (Belgium). P.D. is a Research Associate of the National Fund for Scientific Research (Belgium). Contribution of the Centre Interuniversitaire de Biologie Marine.     

Immunohistochemical study of the adenohypophysis of the monkey Macaca irus with the use of antibodies anti 1-24-ACTH, anti 17-39-ACTH, anti alpha-and beta-endorphins, anti beta-LPM]

Indirect immunofluorescence technique with anti1-24- and anti17-39 ACTH, anti alpha- and anti beta-endorphins, anti beta-LPH sera has allowed us to detect a cellular type in the anterior lobe of the hypophysis of Macacus irus which react simultaneously with these five antisera. These cells are especially localized in the ventro-medial zone, but there are also present in the pars distalis, under the glandular capsule, and in the lateral lobes, amid the other cellular types. The cells of the intermediate lobe react on the whole with anti1-24-, these antisera are also immunoreactive with the anti alpha- and anti17-39ACTH and anti beta-LPH ; SOME CELLS, WHich react with anti beta-endorphin antisera. The adenohypophysis of Macacus irus contains therefore two categories of cells reacting with the above mentioned antisera : one of this type, localized in the anterior lobe and in the intermediate lobe, react simultaneously with the five antisera, the other type, localized only in the intermediate lobe does not react with the antiendorphins antisera.