Timothy A. Ballard

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While parathyroid hormone (PTH), calcitonin (CT), and certain prostaglandins (PGs) are known to regulate the metabolism of both osteogenic and osteolytic cells of the adult skeleton through an adenosine 3', 5'-monophosphate-dependent mechanism, little is known about the development of this hormonally mediated response in embryonic skeletal tissues. In the(More)
The developing chick limb was studied to determine the ability of parathyroid hormone (PTH) and prostaglandin E2 (PGE2) to increase intracellular cyclic AMP (cAMP) during various stages of development. All developmental stages examined (stages 20–21, 24–25, and 26–28) responded to PGE2 when the cells were assayed immediately following the removal of the(More)
Effects of prostaglandins (PGs) on accumulation of cyclic AMP (cAMP) in the presence of a phosphodiesterase inhibitor were investigated in cells isolated from avian limb buds at various stages of development. Cells were responsive to PGE2 at the earliest stage investigated (stage 20-21) which was well in advance of specific cytodifferentiation of limb(More)
The effects of medium supplements were tested on embryonic chick calvarial cells in culture. Isolates were divided among four treatment groups: Nu-Serum, chicken serum, fetal bovine serum, or calf serum. Expression of the osteoblastic phenotype was assessed by cell morphology, DNA content, [3H]thymidine incorporation, lactate production, cellular and medium(More)
Mouse embryo limb cells carrying either the brachypodism (bpH/bpH) mutation or its wild-type (+/+) allele were tested for their ability to accumulate cyclic AMP in response to prostaglandin E2 (PGE2) between Embryonic Days E12 and E14. Mutant cells exhibited a precocious increase in cyclic AMP. In the absence of PGE2 but in the presence of the(More)
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