title: A study of the arrangement of osteoblasts of rat calvarium cultured in medium with, or without, added parathyroid extract.
abstract: The osteoblast layers on the inner surfaces of the half-calvaria of neonatal rats of 2 litters were studied by scanning electron microscopy. Some halves were fixed immediately on dissection. Others were carried through incubation in an Eagle's medium, with or without the addition of parathyroid extract (PTE): for 2, 4, 8 or, most importantly, 24 h. In their initial state, presumed as like the o-h material, the osteoblasts presented as a dense tesselation. After 24 h of culture in the medium, osteoblasts were more sparse in the fields examined and although, in a set of 4 preparations, they retained significant alignment, their orientation had become more random. In addition, they were broader and larger in area. By contrast, with PTE added to the medium, osteoblasts almost maintained their number per field, did maintain their cell area, but became longer and narrower and strikingly parallel in their array. The aligning effect of the PTE preceded, and thus was independent of, its elongating effect.
mesh_terms: D000818:Animals; D002452:Cell Count; D002465:Cell Movement; D002478:Cells, Cultured; D006801:Humans; D007231:Infant, Newborn; D008855:Microscopy, Electron, Scanning; D010006:Osteoblasts / Q000166:cytology*; D010280:Parathyroid Glands / Q000502:physiology; D051381:Rats; D012886:Skull / Q000166:cytology