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Biomedical subjects

R Ornberg

Publications and source records attributed to R Ornberg.

8 recordsLinked to original sources
PubMed1990

Morphological behavior of cultured bovine adrenal medulla capillary endothelial cells.

Bovine adrenal medulla capillary endothelial cells were isolated and cloned, and their morphological behaviors in vitro were examined. In the culture of primary or early passage, one type of colony formed intracellular lumina both on the dish and in the three dimensional collagen gel. Another type proliferated well and showed morphology ranging from slender-shape to cobblestone shape, and were easily cloned. Cloned cells which showed slender-shapes formed tubular network on plastic dish after addition of PMA, OAG or vanadate, and these cells also formed multicellular tubules in the three dimensional collagen gel. However, the formation of diaphragmed fenestrae by these slender-shape clones was rare. One clone which showed cobblestone shape formed diaphragmed fenestrae, when cultured on collagen gel for more than one month. Isolated colonies or clones showed heterogeneity of cell shape, angiogenic behaviors and fenestrae formation.

Adrenal Medulla↗
PubMed1989

Cloned endothelial cells from fetal bovine bone.

Primary cell cultures from fetal bovine sternum were developed in Coon's modified Ham's F-12 medium containing 10% Nu-Serum, 1% Ultroser-G, and 200 mg of galactose per liter. Clones were obtained by colony isolation; one clone, BBE-1, was selected for characterization. BBE-1 cells exhibited typical endothelial morphology by light and electron microscopy and immunofluorescence for factor VIII-related antigen throughout their life span of 8 months. The cells showed mitogenic responses to endothelial cell growth factor, basic fibroblast growth factor, insulin-like growth factor types I and II, platelet-derived growth factor, ascorbic acid, and progesterone. Parathyroid hormone stimulated intracellular accumulation of cAMP in BBE-1 cells but not in endothelial cells from two other tissues. These clonal cells provide a useful system for studies on bone vasculature, including its interactions with other bone cells.

Animals↗
PubMed1987

Differential distribution of signal-transducing G-proteins in retina.

We used specific antibodies in immunoblot studies of membrane fractions derived from bovine retina, and in immunohistochemical studies of sections of rat retina to determine the distribution of two guanine nucleotide binding proteins Go (a G-protein of unknown function discovered in the brain) and transducin, in retina. Both Go and transducin were readily detected in membranes derived from whole retina, and in crude rod outer segment membranes. Purification of rod outer segment membranes by sucrose density gradient centrifugation resulted in enrichment in transducin and depletion of Go immunoreactivity. Transducin-alpha immunoreactivity was localized to photoreceptor inner and outer segments and the outer nuclear layer. In contrast, Go-alpha immunoreactivity was localized in the inner and outer plexiform layers and ganglion cell layer. The results indicate that Go unlike transducin, is not associated with rod outer segment membranes and is therefore unlikely to function in phototransduction. Go is, however, relatively abundant in neural layers of retina where it may be involved in signal transduction.

Animals↗
PubMed1986

Eukaryotic pre-tRNA 5' processing nuclease: copurification with a complex cylindrical particle.

In eukaryotes pre-tRNA species are processed at the 5' end by an endonuclease. Here we describe the first characterization of the structure of a eukaryotic pre-tRNA 5' processing endonuclease. The 5' pre-tRNAase, isolated from X. laevis ovaries, copurifies with a 16S macromolecular complex consisting of at least 14 polypeptides ranging in MW from about 20,000 to 32,000. These polypeptides comprise a cylindrical particle, apparently organized as a stack of four rings, similar or identical to a ubiquitous eukaryotic subcellular particle described in the literature over the past 15 years. Similar copurification is observed for the enzyme from HeLa cells, suggesting that the X. laevis enzyme is representative of a general class of eukaryotic pre-tRNA 5' processing nuclease.

Animals↗
PubMed1985

Synexin binds in a calcium-dependent fashion to oriented chromaffin cell plasma membranes.

Oriented plasma membrane fragments from chromaffin cells, isolated on polylysine-coated polyacrylamide beads, bind synexin in a calcium dependent manner. Synexin binding was also detected on beads coated with chromaffin granule membranes, but not to beads coated with erythrocyte membranes or to uncoated beads. Synexin binding to plasma membrane coated beads showed a specific requirement for calcium (K1 2 = 200 microM) and was insensitive to other divalent cations such as magnesium, strontium and barium. Synexin binding to either plasma membrane or granule membrane coated beads was saturable, was partially reversible by EGTA and was directly observed by SDS-polyacrylamide gel electrophoresis.

Adrenal Medulla↗