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Biomedical subjects

M Osborn

Publications and source records attributed to M Osborn.

At least 253 records · Page 14Linked to original sources
PubMed1979

Identification and characterization of epithelial cells in mammalian tissues by immunofluorescence microscopy using antibodies to prekeratin.

The occurrence of intermediate-sized filaments containing prekeratin-like proteins ('cytokeratins') has been examined in various organs of rat and cow by electron microscopy and by immunofluorescence microscopy on frozen sections using antibodies to defined constitutive proteins of various types of intermediate-sized filaments (prekeratin, vimentin, desmin). Positive cytokeratin reaction and tonofilament-like structures have been observed in the following epithelia: epidermis; ductal, secretory, and myoepithelial cells of sweat glands; mammary gland duct; myoepithelial cells of lactating mammary gland; milk secreting cells of cow; ductal, secretory, and myoepithelial cells of various salivary glands; tongue mucosa; bile duct; excretory duct of pancreas; intestinal mucosa; urothelium; trachea; bronchi; thymus reticulum, including Hassall corpuscles; mesothelium; uterus; and ciliated cells of oviduct. None of the epithelial cells mentioned has shown significant reaction with antibodies to vimentin, the major component of the type of intermediate-sized filaments predominant in mesenchymal cells. The widespread, if not general occurrence of cytokeratin filaments in epithelial cells is emphasized, and it is proposed to use this specific structure as a criterion for true epithelial character or origin.

Animals↗
PubMed1979

Phenomenology associated with depressed moods in adolescents.

The authors studied phenomenology associated with depressed moods in 30 adolescents within a semi-structured interview format using defined symptom items. The results suggest that while there is some symptomatic similarity between adolescent depression and depression in adults, there are many differences that warrant more cautious comparison and further study.

Adjustment Disorders↗
PubMed1979

Cell-to-substratum contacts in living cells: a direct correlation between interference-reflexion and indirect-immunofluorescence microscopy using antibodies against actin and alpha-actinin.

Rat mammary cells growing on glass coverslips were photographed first using interference-reflexion microscopy and then after processing for indirect-immunofluorescence microscopy with antibodies to actin or to alpha-actinin. A comparison of the images of the same cell given by the 2 microscopical procedures indicates that the focal contacts between the cell and the substratum correspond to distal ends of microfilament bundles, and the these bundles are only in limited areas close to the substratum. The focal contracts are rich in alpha-actinin which has been proposed as a membrane-anchorage protein for microfilament bundles. Use of stereo immunofluorescence microscopy allows a direct comparison between the interference-reflexion image, and the underside of the cell after staining with antibodies to actin or alpha-actinin.

Actinin↗
PubMed1979

Ultrastructural, biochemical, and immunologic characterization of Mallory bodies in livers of griseofulvin-treated mice. Fimbriated rods of filaments containing prekeratin-like polypeptides.

Mallory bodies (MBs) induced in hepatocytes by long term feeding of mice with griseofulvin were isolated, purified, and examined by electron microscopy in ultrathin sections and negatively stained preparations. The major structural component of the MBs was randomly oriented, unbranched rods of filaments; these were usually 175 to 250 nm. long and 14 to 20 nm. thick and covered by a dense fimbriate coat of laterally projecting 1.5- to 3-nm. thick threads. Such lateral threads could extend for more than 20 nm. and seemed to be involved in the interconnection of adjacent filaments and their association and aggregation into MBs. Using sodium dodecyl sulfate-polyacrylamide gel electrophoresis, the purified filament material showed six major polypeptide bands with apparent molecular weights ranging from 48,000 to 66,000. When the portion of the MB filament material that was soluble in solutions containing 8 M urea was allowed to reaggregate upon removal of the urea, an enrichment of one of the polypeptide components (approximate molecular weight, 64,000) was observed. When frozen sections of liver tissue MBs were subjected to indirect immunofluorescence microscopy, they were specifically revealed by guinea pig antibodies directed against purified bovine prekeratin. No significant accumulation of MBs was observed with a series of other antisera, including those containing antibodies against tubulin, actin, and vimentin, the major protein of the intermediate sized filaments predominant in mesenchymal cells. The observations suggest that MBs in livers of griseofulvin-treated mice, and probably also of human alcoholic hepatitis, contain large amounts of prekeratin-like polypeptides which are assembled into a special form of fimbriated rods of 14- to 20-nm. filaments. These filaments are morphologically different from other forms of intermediate sized and thick filaments, including the prekeratin-containing 6- to 11-nm. tonofilament-like filaments present in various epithelial cells.

Animals↗
PubMed1979

Microfilament-associated proteins in tissue culture cells viewed by stereo immunofluorescence microscopy.

Stereo immunofluorescence microscopy avoids the problem of juxtaposition of structures often encountered in normal fluorescence microscopy. The procedure has been used in conjunction with antibodies against microfilament associated proteins to reveal the arrangement of microfilaments in a rat mammary cell line both in the fully spread state and in cells during the process of spreading on the substratum. use of antibodies to myosin, tropomyosin, alpha-actinin and filamin emphasizes that at early times during the spreading process these proteins are abundantly present underneath the upper plasma membrane, suggesting that the cortical layer present underneath this membrane may be contractile. In addition the results emphasize that even in well spread cells microfilament bundles are expressed both above and below the nucleus, in agreement with the assumption that microfilaments may form a supporting layer underneath the plasma membrane.

Actinin↗
PubMed1979

Identification of multiple microtubule initiating sites in mouse neuroblastoma cells.

Mouse neuroblastoma N-18 cells can be induced by serum deprivation to sprout multiple neurite-like processes which contain many microtubules. Mitotic drugs such as colcemid and colchicine depolymerize these microtubules and the cells lose their processes. Reappearance of microtubules after removal of the drugs was followed by immunofluorescence microscopy using tubulin specific antibodies. At early recovery times multiple star-like structures which contained tubulin were detected in the perinuclear are and in the cytoplasm of individual cells. The mean number seen per cell as approximately 5. Their formation preceeded the organization of the complex microtubular networks typical of N-18 cells. The probable action of these structures as microtubular organization centers (MTOCs) is discussed. Multiple structures were detected during recovery from the influence of mitotic drugs both in previously induced and non-induced N-18 cells, suggesting that N-18 cells harbour the potential of formation of multiple organization centers even without previous induction. We discuss the possibility that differentiation of neuroblastoma N-18 cells may require microtubular organization centers.

Animals↗
PubMed1978

Changes in intracellular organization of tubulin and actin in N-18 neuroblastoma cells during the process of axon extension induced by serum deprivation.

Specific antibodies against actin and tubulin have been used to follow the distribution and organization of actin and tubulin containing structures in N-18 neuroblastoma cells induced to sprout axons. Immunofluorescence microscopy shows that during the time of axonal sprouting microtubules converge into growing processes forming dense bundles in which individual microtubules cannot be resolved. In the growth cone where individual fluorescent fibers can again be distinguished microtubules seem to be excluded from the very margin. Actin is predominantly located at the cell periphery both in cell bodies and in cell processes. It appears to be present in areas of high surface motility and is especially abundant at the tip of the growth cone.

Actins↗
PubMed1978

Indirect immunofluorescence microscopy of microtubular structures in male germ cells of wildtype and l(3)pl (lethal-polyploid) Drosophila hydei.

Tubulin-containing structures of the male germ cells of Drosophila hydei crossreact in indirect immunofluorescence microscopy with antibody directed against homogeneous porcine brain tubulin. There is no detectable difference in reactivity between germ cells of wildtype flies and the mutant l(3)pl (lethal-polyploid) which is characterized by microtubular abnormalities. However, the technique of indirect immunofluorescence microscopy allows the direct visualization of several abnormalities in the arrangement of the microtubular system of the mutant, particularly in the axonemal complex.

Animals↗
PubMed1978

The intracellular organization of actin and tubulin in cultured C-1300 mouse neuroblastoma cells (clone NB41A3).

Cells of clone NB41A3 of the C-1300 mouse neuroblastoma were grown to a critical density at which many of the cells flatten, assume a variety of shapes and sizes and some sprout processes resembling neurites. We have studied the distribution of actin and tubulin in these cells using fluorescence microscopy and antibodies against actin or tubulin under these conditions. Actin-containing structures are variably arranged and predominantly associated with motile areas of the cell periphery including the growth cone. Microtubules appear to run radially from the perinuclear area towards the cell periphery. When neurites are present, microtubules converge into them and run to the growth cone but rarely contact its edge.

Actins↗
PubMed1978

Stereo immunofluorescence microscopy: I. Three-dimensional arrangement of microfilaments, microtubules and tonofilaments.

An easy manipulation of the commercial fluorescence microscope allows stereo pairs of pictures to be taken, which when examined with a stereo viewer, give a strong three-dimensional impression. The procedure is described in detail. Its use allows the documentation by immunofluorescence microscopy of the three-dimensional display and organization of microfilament bundles, microtubules and tonofilaments in some well characterized tissue culture cell lines.

Actins↗
PubMed1978

Reaction of tonofilament-like intermediate-sized filaments with antibodies raised against isolated defined polypeptides of bovine hoof prekeratin.

Total purified and reconstituted bovine hoof prekeratin, containing several polypeptides, as well as individual polypeptide size classes isolated therefrom were used as antigens in guinea pigs. The antibodies raised against these protein preparations were found to decorate the system of wavy arrays of tonofilament-like, intermediate-sized filaments present in various epithelial and epithelia-derived cells. Strong cross-reaction between different vertebrate species was noted, including amphibia. Positive results were obtained with original sera as well as with IgG fractions and antibodies made monospecific by chromatography on total bovine prekeratin covalently bound to Sepharose. Among the antisera raised against the different polypeptide size classes the most intense decoration of fibrillar arrays was obtained with antibodies against fraction 4 which contained polypeptides VI and VII.

Animals↗
PubMed1978

Different intermediate-sized filaments distinguished by immunofluorescence microscopy.

The major protein of intermediate-sized filaments in mouse 3T3 cells, for which the name vimentin is proposed, has a molecular weight of 57,000. Antibodies against vimentin and antibodies against prekeratin have been used in parallel in immunofluorescence microscopy on a variety of cultured cells as well as on frozen tissue sections. Both antibodies decorate extended wavy arrays of filaments that are different from microfilaments and microtubules. Intermediate filament bundles decorated by antibodies against prekeratin are predominant in many epithelial cells, including epithelia-derived tumor cells, and are not decorated by antibodies to vimentin. In contrast, intermediate filaments decorated by antibodies against vimentin are widespread among nonmuscle cells of mesenchymal origin, including transformed cells, and also occur in other cells. Perinuclear whorls of aggregates of intermediate filaments induced by prolonged treatment with Colcemid generally show strong decoration with antibodies against vimentin. No significant reaction with either antiserum has been observed in muscle structures or in brain nerve tissue. These observations show that intermediate filaments with similar ultrastructure and solubility characteristics can be distinguished immunologically.

Cells, Cultured↗
PubMed1978

Three-dimensional electron microscopical visualization of the cytoskeleton of animal cells: immunoferritin identification of actin- and tubulin-containing structures.

Cytoskeletons prepared by Triton X-100 treatment of tissue culture cells appear in stereo electron microscopy as a highly organized and interconnected three-dimensional matrix of different fibrous elements. Microfilament bundles and also tonofilament-like bundles are readily discerned when present in the cell type. In addition thinner fibers, some of which branch (smallest diameter 30--40 A), as well as fibers of larger diameter, some of which correspond to microtubules, can be seen. Since such cytoskeletons are an open, membrane-free system, individual fibrous organizations can be identified by specific antibodies. An indirect immunoferritin procedure using antibodies to tubulin or actin visualizes microtubules or actin-containing structures. Stereo electron microscopy of cytoskeletons decorated with actin antibody reveals, in addition to the F-actin-containing microfilament bundles, an extended fine actin lattice. This actin net is displayed throughout the cytoplasm not only between the microfilament bundles but also in those regions of the cytoskeleton that in the intact cell correspond to the submembraneous regions. Thus all actin-containing fibrous cytoplasmic structures may be interconnected in the living cell.

Actins↗
PubMed1978

Cytoplasmic microtubular images in glutaraldehyde-fixed tissue culture cells by electron microscopy and by immunofluorescence microscopy.

Electron microscopy and indirect immunofluorescence microscopy using monospecific tubulin antibodies were performed in parallel on glutaraldehyde-fixed tissue culture cells without osmium fixation. In order to reduce the excess aldehyde groups of the strongly crosslinked cellular matrix, which normally interfere with subsequent immunofluorescence microscopy, a mild NaBH(4) treatment was introduced during or after the dehydration steps. Cells processed through the NaBH(4) step show, in transmission electron microscopy, normal cytoplasmic microtubules approximately 250 A in diameter. When such cells are subjected to indirect immunofluorescence microscopy using monospecific tubulin antibody they reveal a complex system of unbroken, fine, fluorescent fibers traversing the cytoplasm between the perinuclear space and the plasma membrane. Thin sections of cells processed through the indirect immunofluorescence procedure show antibody-decorated microtubules with a diameter of approximately 600 A. This decoration is not obtained when non-immune IgGs are used instead of monospecific antitubulin IgGs. Thus, a direct comparison of cytoplasmic microtubules in glutaraldehyde-fixed cells by both electron microscopy and immunofluorescence microscopy can be obtained.

Cells, Cultured↗