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Biomedical subjects

R M Wagner

Publications and source records attributed to R M Wagner.

49 records · Page 3Linked to original sources
PubMed1976

Characteristics of epithelial cella cultured from feline lung.

Cell cultures were initiated by trypsinization of lung tissues obtained from 55-day-old fetuses of Felis catus. After a period of cultivation, the cells were cloned and several clones with an epithelial morphology were established. On electron microscopy, at least four of the clones contained intracytoplasmic lamellar inclusion bodies typical in appearance to those observed in type II alveolar cell in situ. These clones should be invaluable for the study of the biosynthesis of long surfactant.

Animals↗
PubMed1976

Isolated lamellar bodies from rat lung: correlated ultrastructural and biochemical studies.

Lamellar bodies isolated from rat lung homogenates were prepared for electron microscopy by two methods: OsO4 fixation followed by dehydration either with acetone or ethanol. Electron microscopy revealed that the acetone-dehydrated fraction contained many well preserved lamellar bodies with intact outer membrane, and the high retention of a material of low electron density between the fine and closely spaced concentric lamellae. This appearance was contrasted by the increased loss of this interlamellar material and coarse and irregularly spaced lamellae in the ethanol-dehydrated fraction. The supernatants from each respective fixation and dehydration were collected for lipid and protein analyses in an attempt to correlate any detected biochemical difference with a correspondingly modified ultrastructural appearance. Thin layer chromatography on the supernatant from the ethanol-dehydrated fraction revealed the extraction of 40 per cent lecithin and 4 per cent phosphatidylglycerol as compared to 1 per cent lecithin and an undeterminably small percentage of phosphatidylglycerol extracted by acetone dehydration. The effect of fixation and dehydration upon the extraction of chemical components of the lamellar bodies was compared to extraction by those of the following treatments: (1) freezing and thawing (a loss of 7 per cent lecithin, undetectably small losses of phosphatidylglycerol and protein); (2) incubation at 37 degrees C. with magnetic stirring (losses of 35 per cent lecithin, 5 per cent phosphatidylglycerol, and 4 percent protein, respectively); (3) sonication (loss of 57 per cent lecithin, 31 per cent phosphatidylglycerol, and 27 per cent protein, respectively). Further lipid analyses of the supernatants from dehydration and those obtained from the mechanical treatments revealed dipalmitoyl lecithin as the most readily extracted lipid. These data indicate that OsO4 fixation followed by acetone dehydration improves the preservation of the lamellar body ultrastructure by retaining an amorphous material between the lamellae, thus preserving the spatial relationship between the lamellae, and further that this improved morphologic preservation correlates well with retention of disaturated lecithin.

Acetone↗
PubMed1976

Scanning electron microscopy of hepatic ultrastructure: secondary, backscattered, and transmitted electron imaging.

Several methods of tissue preparation and different modes of operation of the scanning electron microscope were used to study the ultrastructure of rat liver. Rat livers were perfusion fixed with buffered 2 per cent paraformaldehyde or a mixture of 1.5 per cent paraformaldehyde and 1 per cent glutaraldehyde and processed as follows. Tissue blocks were postfixed in buffered 2 per cent osmium tetroxide followed sequentially by the ligand-mediated osmium binding technique, dehydration and cryofracture in ethanol, and critical point drying. They were then examined without metal coating in the scanning electron microscope operating in the secondary electron and backscattered electron modes. Fifty-micrometer sections were cut with a tissue sectioner, stained with lead citrate, postfixed with osmium, dehydrated, critical point dried, and examined in the secondary electron and back-scattered electron modes. Frozen sections (0.25 to 0.75 mum. thick) were cut by the method of Tokuyasu (Toluyasu KT: J Cell Biol 57:551, 1973) and their scanning transmission electron microscope images were examined either with a scanning transmission electron microscope detector or with a conversion stub using the secondary electron detector. Secondary electron images of the liver prepared by ligand-mediated osmium binding and subsequent cryofracture revealed such intracellular structures as cisternae of the endoplasmic reticulum, lysosomes, mitochondria, lipid droplets, nucleolus and nuclear chromatin, as well as the usual surface morphology, Lipocytes in the perisinusoidal space were readily identified. Backscattered electron images. Unembedded frozen sections had little drying artifact and were virtually free of freezing damage. The scanning transmission electron microscope image revealed those organelles visualized by the secondary electron mode in the ligand-mediated osmium binding-treated tissue.

Animals↗
PubMed1975

Fine structure of the cell envelope layers of Flexibacter polymorphus.

Electron microscopy of the filamentous gliding marine bacterium Flexibacter polymorphus demonstrated that the cell envelope consists of an electron-dense intermediate layer located between two unit-type membranes: an outer membrane, presumably of lipopolysaccharide, and an inner cytoplasmic membrane. Separation of living filaments into single cells by lysozyme suggests that a peptidoglycan moiety, possibly corresponding to the intermediate layer, might be situated between the two membranes. Cell division proceeds by invagination of the cytoplasmic membrane and intermediate layer forming a transverse septum. Cells generally fail to separate after the division process, so that a common outer membrane encloses all of the cells in a single filament. There is a continuous layer of macromolecular cup-shaped elements ('goblets') attached to the outermost surface of the lipopolysaccharide membrane. Tangential thin sections, as well as negatively stained preparations of envelope fragments (produced by sonication of autolyzed cells), showed that the goblets are arranged in a close-packed hexagonal array. The presence of electron-dense structures located between the outer and inner membranes, and exhibiting the same periodicity as the goblets, suggests that some part of the goblets penetrates the outer membrane and extends across the periplasmic space to the dense intermediate layer or cytoplasmic membrane. Spontaneous autolysis in aging cultures is accompanied by the formation and release into the culture medium of large numbers of outer membrane vesicles coated with globlets. A tentative reconstruction of the envelope of F. polymorphus, based on the fine-structural data, is presented.

Bacteriolysis↗
PubMed1975

Clonal isolation of epithelial cells from mouse lung adenoma.

Clones of epithelial-like cells were established from urethan-induced mouse lung adenoma. Electron microscopy of one clone showed that the cells contained lamellar inclusion bodies similar in appearance to those seen in the adenoma precursor, the type II alveolar pneumocyte. The clones exhibited characteristics associated with both "transformed" and "normal" cells in culture; i.e., although aneuploid, the cells grew at a slower rate than most transformed cells, did not form colonies in soft agar and, after prolonged subculture, were not tumorigenic when transplanted s.c. into appropriate hosts. Hydrocortisone treatment of the cloned cells led to growth stimulation and the eventual acquisition of neoplastic potential. Epithelial tumors were produced more readily in athymic, nude mice than in antilymphocyte serum-treated A/He mice. The cells are producing a C-type RNA virus into the culture medium.

Adenoma↗
PubMedDate not supplied

Antigenic relatedness and partial amino acid sequences of pili of Escherichia coli serotypes O1, O2, and O78 pathogenic to poultry.

Pilus proteins from Escherichia coli serotypes O1, O2, and O78 pathogenic to poultry were compared with regard to their antigenic relatedness and partial amino acid sequences. Agglutination, immunodiffusion, and immunoblot assays with polyclonal antibodies to these pili showed that these pili not only share some common antigens but also contain antigens unique to each pilus. The partial amino-terminal amino acid sequences support our earlier findings that the pili are different but contain some structural homologies.

Amino Acid Sequence↗