Table 1.

Characterization of Osteoblast Clones

Cells	Stimulation of BrdUincorporation by FGF1	Initial Morphology	ALP*		OC‡
			Day 0	Day 5–8	Day 0	Day 5–8
OB1	8-fold	Spindle shaped	±	++	−	+
OB2	6-fold	Spindle shaped	±	++	−	+
OB3	1.5-fold	Cuboidal	++	++	++	++
OB4	2-fold	Cuboidal	+	+	++	+++
Primary OB	3-fold	Mixed	+	+++	+	+++

*Alkaline phosphatase (ALP) expression was determined by Northern analysis and by histochemical staining upon initial plating (day 0) and after 5–8 d of differentiation.

^‡Osteocalcin (OC) levels were assessed by Northern analysis upon initial plating (day 0) and after 5–8 d of differentiation.