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Biomedical subjects

M Schachner

Publications and source records attributed to M Schachner.

At least 469 records · Page 26Linked to original sources
PubMed1979

Effects of aldehydes and organic solvents on concanavalin A binding sites in cerebellar tissue sections.

Fresh frozen cerebellar sections of adult mice treated with aldehydes and organic solvents reveal differences in detectability of Concanavalin A (Con A) binding sites. While fluorescein coupled Con A shows intense labeling of synaptic glomeruli and granule cell bodies under all conditions, the molecular layer labels intensely after treatment with paraformaldehyde, glutaraldehyde, acetone, ethanol and butanol. Complete loss of staining in molecular and granular layers and substantial increase in white matter labeling occurs after chloroform-methanol treatment. Except for glutaraldehyde treated sections, all labeling is specifically inhibited by methyl-alpha-D-mannoside, but not by galactose.

Aldehydes↗
PubMed1979

Effects of pseudomonas toxin A, diphtheria toxin, and cholera toxin on electrical characteristics of turtle bladder.

Rapidly developing changes in the short-circuiting current (Isc), conductance (G), and potential (PD) of turtle bladders in Na-rich or Na-free media are seen after the mucosal addition, at 10 nM, of each of three toxins that contain ADP-ribosylation activity: Pseudomonas aeruginosa toxin A, diphtheria toxin, and cholera toxin. Toxin A irreversibility decreased the Isc, PD, and G of bladders in Na-rich media and the Isc and PD of bladders in Na-free media. Diphtheria or cholera toxin reversibly increased Isc and PD (not G), but only in Na-free media. The effects of toxin A in the turtle bladder, like those in other host cell systems, were eliminated by preexposure of this toxin to heat, specific antitoxin, or dithiothreitol and urea. Because exposure to this last condition increases the ADP-ribosylation activity of toxin A, it is suggested that the proenzyme is the required transport-inhibiting form of toxin A. The effects of all three toxins occurred rapidly, possibly before any of the possible intracellular ADP-ribosylation reactions are initiated. Whereas a recognition binding of toxin of toxin to receptors on the apical membrane completely accounts for the reversible effects of diphtheria or cholera toxin, this and additional toxin-membrane interactions (e.g., translocation) are needed to account for the irreversible effects of toxin A.

Animals↗
PubMed1979

Cell type-specific neural cell surface antigens.

Immunological methods have served to define several cell surface antigens that are differentially expressed among neural cell types and are developmentally regulated. These antigens have served as useful markers for cell identification and isolation of several neural cell types. The molecular nature and functional properties of almost all of these antigens are presently unknown.

Animals↗
PubMed1978

Immunological distinction between neurofilament and glial fibrillary acidic proteins by mouse antisera and their immunohistological characterization.

Antisera were raised in mice to the presumed protein subunits of the two types of 100 A filaments in nervous tissue, glial fibrillary acidic (GFA) protein and neurofilament (NF) protein. These antisera detect a pronounced antigenic distinction between these two proteins. Antiserum to GFA protein reacts only with astroglial cells and is therefore similar to antisera prepared in rabbits. Mouse antiserum to NF protein reacts with neurons and their processes known to be rich in 100 A filaments. Postsynaptic densities do not detectably react with anti-NF antiserum when assayed by the indirect immunoperoxidase method and studied at the electron microscopic level. The two antisera do not react with actin, myosin oe nervous system, NF protein is immunohistologically detectable at embryonic day 13 (the earliest stage tested). GFA protein is not detectable with this method during embryonal development but becomes apparent only at early postnatal ages. In several species (rabbit, rat, chicken, fish, turtle, and frog) anti-NF protein antiserum only reacts with neurons, and anti-GFA protein antiserum stains glia exclusively. On the surface of trypsin-dissociated, single liver cerebellar cells from 7-day-old mice, each antiserum detects antigenic specificities which are cross-reactive with its corresponding antigen.

Animals↗
PubMed1978

Localization of nervous system antigens in retina by immunohistology.

Several antigens expressed in the nervous system were localized in tissue sections of developing and adult mouse retina by indirect immunofluorescence. Two antigens expressed in oligodendrocytes, basic protein of myelin, and NS-1 are not detectable. Antisera against nervous system-3, -4, and -7 antigens (NS-3, NS-4, and NS-7) give a uniformly intense reaction on all retinal cell structures. Large, external, transformation-sensitive (LETS) protein is present on blood vessels. Glial fibrillary acidic (GFA) protein is absent at birth but is found after day 4 in cells of the ganglion cell and nerve fiber layers. GFA protein--positive cells extend in parallel from inner to outer limiting membranes only at the ora serrata and around the optic nerve. No other glial elements contain GFA antigen, suggesting two distinct populations of astrocytes. Neurofilament (NF) protein--positive cells are present in the adult retina in outer plexiform and ganglion cell layers. By day 4 the ganglion cell layer and the ependymal zone have become NF-positive.

Animals↗
PubMed1977

Phenotypic properties of neoplastic cell lines developed from fetal rat brain cells in culture after exposure to ethylnitrosourea in vivo.

We have recently reported that fetal BD IX-rat brain cells (FBC), transferred to long-term culture after a transplacental pulse of EtNU on the 18th day of gestation, undergo neoplastic transformation in vitro ("BT-cell lines"). Tumors developed upon s.c. reimplantation of BT-cells into baby BD IX-rats, appeared histologically as neurinoma-, glioma- or glioblastoma-like, and frequently as pleiomorphic neoplasms. In spite of a more atypic cellular morphology, these tumors grossly resembled the different types of neuroectodermal rat neoplasms induced by EtNU in vivo. Like the neoplastic cell culture lines derived from EtNU-induced, neuroectodermal BD IX-rat tumors ("V-cell lines"), the BT-lines contained multipolar glia-like cells, but also flat cells with fewer and shorter cytoplasmic processes, and occasionally giant cells. Both the V- and BT-lines showed different levels of aneuploidy. They contained multiple subpopulations of cells, as reflected, e.g., by plurimodal pulse-cytophotometric DNA distributions. All lines contained, to varying degrees, the nervous system-specific protein S-100, a "marker" not yet expressed in FBC. There was no indication of more than borderline neurotransmitter activity, suggesting that proliferating (precursor) cells of glial lineages may preferentially undergo malignant transformation after exposure to EtNU during this stage of brain development.

Animals↗
PubMed1977

Brain cell surface antigens detected by anti-corpus callosum antiserum.

When rabbits are injected with tissue homogenates of white matter from bovine corpus callosum, an antiserum is produced which reacts with the surface membrane of 20-30% of all cells obtained by trypsin-dissociation of cerebellum from 10-day-old mice. The antigen or set of antigens recognized by this antiserum is detectable on embryonic, early postnatal, and adult mouse brain, but not on liver, spleen, kidney, thymus and sperm. The antigen is expressed in different regions of the brain and also, in decreased amounts, on retina. In histological sections of cerebellum from 21-day-old mice the antigen is predominantly localized in white matter tracts. Whereas nervous tissue from chicken and rabbit does not carry detectable levels of the antigen, rat, bovine and human brains are antigen-positive.

Age Factors↗