Studies on guinea pig skin cell cultures. VII. Statistical analysis of growth and maturation

Thymidine uptake; incorporation of amino acids into perchloric acid extract and HCl extract (corresponding grossly to poorly and highly organized proteins respectively); cell fraction DNA and cell fraction protein contents have all been measured daily from day 1 to day 8 in primary cultures of epidermal keratinocytes (EK) and dermal fibroblasts (DF). Correlations between these five biochemical parameters (or variables) have been sought when using the statistical method of principal component analysis. The analysis of whole data of EK and DF populations taken together revealed that DNA content is a major distinguishing factor between these two cell types. The analysis of variables of each cell type taken independently showed that DF are essentially characterizable by their tendency to synthesize both poorly and highly organized proteins, whereas EK are more prone to DNA and highly organized protein synthesis. Thus, EK and DF in culture can be readily distinguished statistically by analysing their growth and maturation characteristics. It is even likely that time study of thymidine and amino acid incorporation would suffice to characterize these two cell types in vitro.