Cell density dependence of transformation frequencies in C3H10T1/2 cells exposed to X-rays.
The effects of cell density on transformation frequencies were studied in C3H10T1/2 cells exposed to 0.5 and 7 Gy of 200 kVp X-rays. Initial cell density strongly influenced transformation frequency; this decreased by a factor of between 4 and 10 when the initial seeding density was changed from 50 to 2500 cells/10 cm diameter Petri dish. The data were fitted with two equations: (a) an allometric function represented on a log-log scale by a straight line and (b) a sigmoidal function with plateaux between 50 and 250 cells/dish and above 600. The two curves are compared and their probabilities discussed. Our data indicate that the region between 50 and 250 cells/dish would be the most suitable region for dose-effect measurements. A study of the growth curves at 0.5 and 8.5 Gy shows that cell growth rates are not influenced by initial cell density.
Bettega
D
D
Dipartimento di Fisica dell'Università di Milano, Italy.
Calzolari
P
P
Ottolenghi
A
A
Rimoldi
E
E
Tallone Lombardi
L
L
D000818:Animals; D002452:Cell Count; D002460:Cell Line; D002471:Cell Transformation, Neoplastic / Q000528:radiation effects*; D066298:In Vitro Techniques; D051379:Mice