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Biomedical subjects

G M Fuller

Publications and source records attributed to G M Fuller.

89 records · Page 5Linked to original sources
PubMed1978

Alterations of cytoskeletal morphologies and growth patterns in human fibroblasts treated with polyethylene glycol.

Non-transformed human fibroblasts, strain PA-2, were treated with polyethylene glycol (PEG) in monolayer culture to produce multinucleate fibroblast homokaryons. Antibodies to tubulin or actin were used to monitor cytoplasmic microtubule and actin filament patterns immediately after cytoplasmic fusion, as well as after the fused cells had been in culture for varying amounts of time. The cytoplasmic microtubule complex as increased for a short time after cell fusion and then decreased to resemble the complex seen in control cells. The actin stress fibers were similarly enhanced for a comparable period of time. However, this initial enhancement of the actin stress fibers gradually diminished for approximately one month in culture after which the fibers were greatly reduced in both size and number. Concurrent with the changes in cytoplasmic microtubule and actin fiber complexes, the PEG-treated cells began to show alterations in growth parameters which progressively resembled those characteristic of transformed cell populations. Fusion of normal cells may be an initial step in the transformation of such cells to malignancy.

Actins↗
PubMed1977

Immunochemical characterization of fibrinogen induction in rat liver.

The synthesis of fibrinogen in rat hepatocytes can be induced two to three times its normal level following an injection of turpentine. Detection of the increased synthesis of this protein was accomplished by quantitative immunoprecipitation analysis. The time sequence for maximal intracellular synthesis occurs more rapidly than the concomitant rise in plasma fibrinogen, implying that the secretion of fibrinogen is somewhat slower than was anticipated. Binding studies with 125I-labeled anti-fibrinogen to the nascent chains on the ribosomes showed no detectable changes in the radioactivity distribution before or after stimulation as analyzed by zone sedimentation. It was estimated that only 4.4% of the total polysomes were involved in fibrinogen synthesis prior to induction and this was increased to 15% following turpentine stimulation. The results suggests that the rise in fibrinogen synthesis during the acute-phase response was related to an increase in functional messenger RNA transcripts rather than in an increase in the rate of protein synthesis.

Animals↗
PubMed1976

Structure and control of assembly of cytoplasmic microtubules in normal and transformed cells.

Indirect immunofluorescence analyses using antibodies directed against 6S tubulin have shown an elaborate cytoplasmic microtubule complex (CMTC) in nontransformed cells in culture. The CMTC is strikingly altered in cells that have been transformed spontaneously by viruses or by chemicals. Assembly of microtubules in vitro and in vivo is markedly inhibited in the presence of elevated levels of calcium. Alteration of the surface of normal cells by brief treatment with low concentrations of trypsin initiate a rapid breakdown of cytoplasmic microtubules. Finally, a hypothesis is presented relating microtubule assembly and surface membrane modulation suggesting that calcium is the primary modulating signal.

Antibodies↗
PubMed1975

Radioimmunological identification of polysomes synthesizing fibrinogen polypeptide chains.

Hepatocytes of rats stimulated by turpentine into a hyperfibrinogenemic state produce sufficient quantities of fibrinogen to permit unequivocal identification of specific polysomal complexes involved in the synthesis of this molecule. Monospecific antibodies directed against intact fibrinogen and one of its subunits, the gamma-chain, have shown two size classes of polysomes. Furthermore, it seems possible that polypeptide chain assembly may occur by having completed nascent chains bind to partially completed chains that are still attached to the polysome.

Animals↗