TABLE IV.

a Distribution of Cells Positive for MyoD, Myogenin, or Cyclin A in C2 Cultures
		Number of Cells Per Ten Fieldsa
Days in 2% FCS	Growth Factor Added	Total Number of Cells	MyoD+ cells		Myogenin+ cells		Cyclin A+ cells
			Number	% of Total Cells	Number	% of Total Cells	Number	% of Total Cells
1	None	216.5 ± 6.5	4 ± 2.2	1.9 ± 1.1	-	-	30.0 ± 3.8	13.8 ± 1.3
	PDGF	318.2 ± 9.2	5.5 ± 0	1.7 ± 0.0	-	-	68.2 ± 6.2	21.8 ± 2.6
	FGF	395 ± 28.2	7 ± 1.5	1.7 ± 0.2	-	-	15.0 ± 0.5	3.8 ± 0.1
2	None	657.5 ± 21.5	82.5 ± 18.5	12.4 ± 2.4	-	-	24 ± 7.0	3.6 ± 0.9
	PDGF	1762.5 ± 120.5	159 ± 28	8.9 ± 0.9	-	-	175 ± 8.0	10 ± 1.1
	FGF	2599 ± 136.0	305 ± 31	11.8 ± 1.8	-	-	179 ± 12.0	6.9 ± 0.1
3	None	649 ± 17		-	31 ± 1	5.1 ± 0.3	20.5 ± 5.5	3.1 ± 0.7
	PDGF	1452.5 ± 84.5	-	-	67.5 ± 8.5	3.8 ± 0.2	163 ± 2.6	9.2 ± 1.0
	FGF	2349.5 ± 27.5	-	-	156.5 ± 11.5	6.9 ± 0.2	169.5 ± 29.5	7.2 ± 1.3

b Dual Expression of MyoD/Cyclin A or Myogenin/Cyclin A in C2 Cultures
			Number of Positive Cells Per Actual Number of Fields Anayzeda
Days in 2% FCS	Growth Factor Addeda	Actual Number of Fields Analyzed per Plate	MyoD/Cyclin A		Myogenin/Cyclin A
			All MyoD+	MyoD+ which are also Cyclin A+	All Myogenin+	Myogenin+ which are also Cyclin A+
1	None	23	4	0	-	-
		24	15	4	-	-
	PDGF	20	11	6	-	-
		20	11	2	-	-
	FGF	20	17	0	-	-
		20	11	0
3	None	10	101	7	35	3
		10	64	1	32	2
	PDGF	10	187	9	60	1
		10	131	8	76	0
	FGF	10	274	13	155	10
		10	336	17	170	2

^aCultures were initiated at 4.8 × 10⁴ cells per 35 mm plate using proliferation medium. Following 24 hours cultures were switched to the 2% FCS medium ± growth factors. Numbers reflect mononucleated cells. Fusion into myotubes was not observed at any of the time points. Data for day 3 are based on assaying 10 microscopic fields per plate and represent the average of duplicate plates. Data for day 1 were obtained by analyzing 20–24 microscopic fields per plate using duplicate plates; numbers were then averaged per ten fields per plate.

^aFor all details refer to Table IVa