No description available.

No description available.

This study examined the effects of basic fibroblast growth factor (bFGF), insulin-like growth factor I (IGF-I) and transforming growth factor beta (TGF-β) on the proliferation and differentiation of bovine satellite cells (BSC) in vitro. Cells were treated with serum-free defined media containing varying concentrations of bFGF, IGF-I and TGF-β. On day 3 of treatment total cell nuclei and myotube nuclei were determined. bFGF stimulated BSC proliferation in a dose-dependent fashion with half-maximal stimulation observed at a concentration of 5 ng/ml (p < .05). Similar results were found for IGF-I and TGF-β in the presence of FGF, with half-maximal stimulation observed at 5 ng/ml and 1 ng/ml, respectively. With regard to differentiation, TGF-beta inhibited myotube formation at concentrations above 0.05 ng/ml. IGF-I stimulated myotube formation at concentrations as low as 10 ng/ml (p < .05). These results demonstrate that proliferation and differentiation of BSC in vitro are affected by growth factors, and consequently, similar effects may be found in vivo. This information may prove to be useful in future methods of manipulating muscle growth in vivo.

published_or_final_version / abstract / toc / Psychiatry / Master / Master of Philosophy

published_or_final_version / abstract / Surgery / Doctoral / Doctor of Philosophy

published_or_final_version / Biological Sciences / Master / Master of Philosophy

No description available.

The in vitro study of muscle cell growth is hampered by the presence of non-muscle cells, particularly fibroblasts. The heterobifunctional cross-linking agent, N-succinimidyl 3-(2-pyridyldithio) propionate (SPDP) has been used to create a novel "toxic growth factor" to address the problem. Epidermal growth factor (EGF), which stimulates fibroblast but not satellite cell proliferation, was conjugated via SPDP to a potent ribosome inhibitor, pokeweed antiviral protein (PAP). By preferentially binding to fibroblasts, it was hoped that EGF-PAP could cytotoxically eliminate fibroblasts from primary cultures of rat skeletal muscle satellite cells. While EGF-PAP did prove to be a fibroblast cytotoxin, it could not completely eliminate them from cell cultures. Low dose-time exposures improved the ratio of multinucleated cells to mononucleated cells (percent fusion) by up to 66% over controls, but increased concentrations, or durations of EGF-PAP treatment, proved detrimental to satellite cell growth and/or differentiation.

No description available.

No description available.