Interaction of somatostatin with isolated cytosol from rabbit renal papilla

Specific binding sites for somatostatin have been characterized in cytosolic fraction of rabbit renal papilla. The interaction of 125I-Tyr11-somatostatin with cytosolic fraction was rapid, reversible, specific, saturable and dependent on temperature. At 25 degrees C the binding data were compatible with the existence of two classes of binding sites: a high-affinity class with a Kd = 57.7 nM and a low-affinity class with a Kd = 217.4 nM. Somatostatin binding sites exhibited a high degree of specificity since neuropeptides such as Leu-enkephalin, neurotensin, substance P, vasopressin and vasoactive intestinal peptide behaved as ligands with null or very low affinity.     

Ultrastructural observations on rabbit blastocysts after maternal exposure to cadmium chloride

Cadmium chloride (CdCl2) (0.1 or 1.0%) was given in the drinking water to pregnant rabbits on Days 0 to 5 of gestation. Electron microscopy of the blastocysts revealed significant changes in the lysosomes (e.g. autophagic vacuoles and residual bodies) of endodermal cells as well as those of the inner cell mass. No such changes were evident in the trophoblast.     

Immunohistochemical localization of a protein fraction derived from rabbit renal papilla

Summary Studies were carried out to define antigenic characteristics of the rabbit renal collecting duct. Renal papillae of adult rabbits were homogenized, centrifuged, and the 600×g pellet was extracted with 0.5% Triton X-100 in the presence of 1 M NaCl. The crude extract was fractionated on an anion exchange column (DEAE cellulose). A fraction enriched in acidic proteins that co-purified with a radioactive 150 kd glycoprotein from cultured collecting duct cells (Minuth 1982), was used for immunization of guinea pigs. The antiserum shows the following characteristics as revealed by indirect immunofluorescence on the rabbit kidney: 1) Among all tubular epithelial cells only principal cells of the collecting duct and the connecting tubule cell show immunoreactivity. 2) The antiserum decorates the epithelial-interstitial interface of the whole collecting duct as well as of connecting tubule and thick ascending limb of Henle's loop. 3) There is immunoreactivity of interstitial fibers throughout the kidney. 4) Epithelial cells in a variety of other organs in rabbit did not react with the antiserum.Our data demonstrate an antigenic distinction of both, the connecting tubule cell and the principal cell, discriminating these cells from other tubular epithelial cells including the intercalated cells of the collecting duct system. Furthermore, our findings point to a heterogeneity along the distal nephron with respect to the constituents of the epithelial-interstitial interface.     

Immunohistochemical localization of a protein fraction derived from rabbit renal papilla

Studies were carried out to define antigenic characteristics of the rabbit renal collecting duct. Renal papillae of adult rabbits were homogenized, centrifuged, and the 600 X g pellet was extracted with 0.5% Triton X-100 in the presence of 1 M NaCl. The crude extract was fractionated on an anion exchange column (DEAE cellulose). A fraction enriched in acidic proteins that co-purified with a radioactive 150 kd glycoprotein from cultured collecting duct cells (Minuth 1982), was used for immunization of guinea pigs. The antiserum shows the following characteristics as revealed by indirect immunofluorescence on the rabbit kidney: 1) Among all tubular epithelial cells only principal cells of the collecting duct and the connecting tubule cell show immunoreactivity. 2) The antiserum decorates the epithelial-interstitial interface of the whole collecting duct as well as of connecting tubule and thick ascending limb of Henle's loop. 3) There is immunoreactivity of interstitial fibers throughout the kidney. 4) Epithelial cells in a variety of other organs in rabbit did not react with the antiserum. Our data demonstrate an antigenic distinction of both, the connecting tubule cell and the principal cell, discriminating these cells from other tubular epithelial cells including the intercalated cells of the collecting duct system. Furthermore, our findings point to a heterogeneity along the distal nephron with respect to the constituents of the epithelial-interstitial interface.     

Ultrastructural observations on the gills of polychaetes

The gills of several polychaete species belonging to 9 families were studied by scanning and transmission electron microscopy. The surface epithelium is covered by a thin cuticle which is invaded by microvilli penetrating the epicuticle in certain species. Some epithelial cells bear cilia, others are mucus-producing cells. The ciliary cells may be arranged in rows and maintain a constant flow of water over the gills. The distance between external water and blood stream differs considerably according to the species investigated. InMalacoceros the gills are characterized by closed afferent and efferent subepithelial vessels, which correspond to tubular invaginations of the coelomic wall. These vessels are lined by the basement lamina of the coelothelial cells, which are of the epitheliomuscular type. The vessels are open in the gills of other polychaetes and release the blood stream into a system of spaces immediately below the epidermis (e.g. in the branchial lamellae ofPectinaria andTerebellides). In several species the blood comes into very intimate contact with the cuticle (e.g. in the gill filaments ofDendronereides), but also in these animals both are separated by a very small epidermal layer.Supported by DFG Sto 75/3-6.     

Ultrastructural observations on choroid melanoma

Twelve melanoblastomas of the choroid of different histological types have been studied in the semi-thin sections and at transmission electron microscope. There have been also observed at scanning electron microscope. The ultrastructural findings show some differences in the main cellular types as observed at light microscope by Callender (spindle-shaped cells A and B and epithelioid). In the epithelioid and spindle-shaped B cells a higher number of ribosomes and of mitochondria and large, polymorphous, often multiple nucleoli with reticular structure are observed. There findings may be related to a greater metabolic activity and anaplastic tendency of these cells. Moreover in spindle B - and epithelioid - cell types atypical melanogenesis and nuclear bodies are particularly evident. Scanning electron microscope show well developed cytoplasmic extensions in spindle cells.     

Ultrastructural observations on the marine fouling diatomAmphora

Ecological and Scanning electron microscope (S. E. M.) studies indicated that the diatomAmphora was an important constituent in the initial colonization of test panels coated with a copper antifouling composition.Amphora was also found as the dominant fouling diatom species on paint samples from in-service supertankers and yachts. Associated with the diatom was copious amounts of mucilaginous material, which often encapsulated the cells. Histochemical analysis of the mucilage indicates that it is predominantly polysaccharide in nature. Using the Transmission electron microscope (T. E. M.) and electron microscope cytochemistry the intracellular origin of the adhesive was investigated. T. E. M. and S. E. M. observations of acid-cleaned-cells indicate that the mucilage may be secreted through specialized regions of the frustule. Material isolated from antifouling panels was compared with laboratory culturedAmphora spp. for copper resistance and internal accumulation using TEMSCAN — X ray analytical equipment.     

Ultrastructural observations on oogenesis in Drosophila

The ultrastructure of the follicle cells and oocyte periplasm is described during the stages of oogenesis immediately prior to, during, and immediately subsequent to, vitellogenesis. A number of features have not been described previously in Drosophila. Some yolk appears prior to pinocytosis of blood proteins. However, most of the protein yolk forms while the periplasm is filled with micropinocytotic invaginations and tubules derived from the oolemma. These tubules retain the internal layer of material characteristic of coated vesicles and are found to fuse with yolk spheres. No accumulation of electron-dense material in the endoplasmic reticulum or Golgi of the oocyte is found. Both trypan blue and ferritin are accumulated by the oocyte. The follicle cells have an elaborate endoplasmic reticulum during the period of maximum yolk accumulation. Adjacent cells are joined at their base by a zonula adhaerens, forming a band around the cells, and by plaques of gap junctions. Gap junctions are also present between nurse cells and follicle cells. During chorion formation, septate junctions also appear between follicle cells, adjacent to the zonula adhaerens.