Search PubMed⌕ Search

Biomedical subjects

K Weber

Publications and source records attributed to K Weber.

At least 739 records · Page 41Linked to original sources
PubMed1975

Ultrastructural evidence for lack of tissue damage in a local immune complex reaction: a study of a mild passive Arthus reaction.

An electron microscopic study of a mild reversed passive Arthus reaction (RPAR) was performed using a horeradish peroxidase (HRP)-anti-HRP system to demonstrate the biological usefulness of the process which exists to clear tissue of immune complexes. To disclose the antigen, HRP, the biopsy material was subjected to a peroxidase reaction. HRP was mainly detected within irregular electron-dense precipitates which were considered insoluable HRP-anti-HRP immune complexes. Neutrophils were found to phagocytose and digest the deposited immune complexes in a similar way as described previously. But there was no vascular and other tissue damage. This study provides morphological evidence that the process of clearing tissues of immune complexes need not be harmful to the host.

Animals↗
PubMed1975

The host factor required for RNA phage Qbeta RNA replication in vitro. Intracellular location, quantitation, and purification by polyadenylate-cellulose chromatography.

The Qbeta host factor, a heat-stable protein necessary in concert with Qbeta replicase for phage Qbeta RNA replication in vitro, has been localized in Escherichia coli and found to be associated primarily with ribosomes. This location has been established both by complement fixation assays with highly specific antiserum directed against the host factor, and by in vitro stimulation of Qbeta RNA replication by the Qbeta replicase. The complement fixation assay has provided the estimate that there are approximately 2500 copies of the host factor polypeptide per cell. The host factor is released from the ribosomes by a 1 M NH4Cl wash and concentrated by ammonium sulfate precipitation. It can be purified to apparent homogeneity in one further step by chromatography on poly(A)-cellulose. Ribosomal protein S1 subunit I of Qbeta replicase) also binds to the poly(A)-cellulose column and elutes before the host factor. In agreement with previous reports, we find that the host factor has a monomer molecular weight of 12,000 as judged by sodium dodecyl sulfate-polyacrylamide gels, and a native molecular weight of 72,000 as judged by the stoichiometric interaction of the host factor with Qbeta RNA, by sedimentation in sucrose velocity gradients, and by sodium dodecyl sulfate gel mobility when incompletely disaggregated. The Qbeta host factor is a potent inhibitor of an in vitro poly(A)-directed polylysine protein-synthesizing system, but has less effect on the in vitro translation of poly(U), R17 RNA, late T7 mRNA, or endogenous E. coli mRNA. The amino acid composition and NH2- terminal sequence rule out the host factor as one of the known 30 S or 50 S E. coli ribosomal proteins. The finding that the Qbeta host factor is associated with ribosomes in vivo completes the demonstration that all of the host-supplied proteins required for phage Qbeta RNA replication in vitro are either associated with ribosomes or are involved in the protein-synthetic machinery of the cell.

Animals↗
PubMed1975

Antibody against tuberlin: the specific visualization of cytoplasmic microtubules in tissue culture cells.

Cytoplasmic microtubules in tissue culture cells can be directly visualized by immunofluorescence microscopy. Antibody against tubulin from the outer doublets of sea urchin sperm flagella decorates a network of fine cytoplasmic fibers in a variety of cell lines of human, monkey, rat, mouse, and chicken origin. These fibers are separate and of uniform thickness and are seen throughout the cytoplasm. The fibers disappear either in a medium containing colchicine or after subjection of the cells to low temperature. The same treatments do not destroy the microfilamentous structures that are visualized by means of antibody against actin. When tryspin-treated enucleated cells are replated and then stained with antibody against tubulin, the fibers can be seen to traverse the entire enucleated cytoplasm.

Animals↗
PubMed1975

Patterns of organization of actin and myosin in normal and transformed cultured cells.

The patterns of distribution of intracellular actin and myosin were examined by specific immunofluorescence in a series of normal, simian-virus-40-transformed, and revertant cell lines of rat and mouse origin. A consistent correlation was found between sensitivity to anchorage-dependent growth control and the presence of large, thick sheaths of actin-containing material. The presence of these sheaths was temperature-dependent in a rat line transformed by a temperature-sensitive mutant in the complementation group A of the oncogenic virus simian virus 40.

Actins↗
PubMed1975

SV40: T antigen, the A function and transformation.

T antigen, a protein found in the nuclei of SV40-transformed and -infected cells, can be purified and characterized. Our data suggest that T antigen in transformed cells is found at least in part in a large 22S complex, suggesting that this 22S form may contain T antigen complexed with other viral or host proteins. We prefer the assumption that T antigen is correlated with the A function, although a definitive in vitro proof for this hypothesis is still missing. Mutants in the A function most likely interfere with the maintenance of transformation, a result inviting the interpretation that the A function may indeed govern DNA synthesis of the transformed cell or influence the cell's ability to pass from G1 (or G0) to S. Thus transformation by SV40 may be a direct consequence of the introduction of the SV40 replicon and the presence of its initiator function which is used by the transformed cell.

Antigens, Neoplasm↗
PubMed1975

Simian virus 40 gene A function and maintenance of transformation.

Transformants have been isolated after infection of rat embryo cells at 33 C with either wild-type simian virus 40 or with the temperature-sensitive gene A mutants, tsA7 and tsA28. Examination of properties usually associated with transformation such as growth in 1% serum, growth rate, saturation density, and morphology show that these properties are temperature dependent in the tsA transformants characterized, but are not temperature dependent in the wild-type transformants that have been examined. In the most thoroughly characterized tsA transformants the expression of T antigen also appears to be temperature dependent. These data suggest that an active A function is required for the maintenance of transformation in these cells. In the lytic cycle, the A function is involved in the initiation of DNA synthesis. Thus transformation by simian virus 40 may be the direct consequence of the introduction of the simian virus 40 replicon and the presence of its DNA initiator function, which causes the cell to express a transformed phenotype.

Actins↗
PubMed1975

[Permanent education].

Explore the source record for details and available documents.

Education, Nursing, Continuing↗