Abstract: This quantitative method for the assay of growth factor activity in vitro was developed empirically. Based on the empirical equations, it seems logical to express the cell growth rate by cell duplication frequency, f, and the growth factor activity by the normalized cell growth rate: 1(T-Tmin). The latter is recommended as the basis of defining an arbitrary unit of growth factor activity. For the in vitro growth factor activity assay, the quantitative method based on the empirical equations has two important features: (1) it appears to express linearly the growth factor concentration in assay, and (2) it is not affected by the initial cell counts and the length of cultivation. The view that these two features overcome the apparent defects associated with the expression systems that use the cell count ratio and net cell count is discussed. The quantitative method based on the empirical equations has been verified with experiments and compared with expression systems using the cell count ratio and net cell count. The experiments, which verified the quantitative method based on the empirical equations, were carried out with four selected cell lines: aortic endothelial cells, mouse 3T3 fibroblasts, Walker 256 carcinoma, and Chang's liver cells, using serum as the source of growth factor(s) for all cell lines. Vitreous, retinal extract, and Walker 256 carcinoma extract were also used for aortic endothelial cells.
Publication Year: 1981
Publication Date: 1981-11-01
Language: en
Type: article
Indexed In: ['crossref', 'pubmed']
Access and Citation
Cited By Count: 15
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