Carol C. Pilbeam

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Prostaglandins (PGs) are multifunctional regulators of bone metabolism that stimulate both bone resorption and formation. PGs have been implicated in bone resorption associated with inflammation and metastatic bone disease, and also in bone formation associated with fracture healing and heterotopic ossification. Recent studies have identified roles for(More)
We investigated the vitamin D status of a Caucasian elderly population in a long-term-care facility in Boston. Comparison was made with a group of free-living elderly people. The sunlight exposure of residents was monitored and its effect on the serum concentrations of 25-hydroxyvitamin D [25(OH)D] was compared with contributions from diet and(More)
Bone tissue responds to mechanical stress with adaptive changes in mass and structure. Mechanical stress produces flow of fluid in the osteocyte lacunar-canalicular network, which is likely the physiological signal for bone cell adaptive responses. We examined the effects of 1 h pulsating fluid flow (PFF; 0.7 +/- 0.02 Pa, 5 Hz) on prostaglandin (PG) E2,(More)
Mechanical loading of bone may be transmitted to osteocytes and osteoblasts via shear stresses at cell surfaces generated by the flow of interstitial fluid. The stimulated production of prostaglandins, which mediates some effects of mechanical loading on bone, is dependent on inducible cyclo-oxygenase 2 (COX-2) in bone cells. We examined the fluid shear(More)
A second prostaglandin G/H synthase (PGHS-2), encoded by a gene separate from that for the original PGHS (PGHS-1), has recently been identified. We have shown that PGHS-2 is expressed in cultured mouse calvariae and have compared regulation of PGHS-2 and PGHS-1 messenger RNA (mRNA) levels. PGHS-2 mRNA was not detectable in freshly isolated bones, but was(More)
Prostaglandins (PGs) have been postulated to amplify their own production by stimulating cyclic adenosine monophosphate activity, which in turn stimulates PG production. We examined regulation of messenger RNA levels for the inducible and constitutive prostaglandin G/H synthases, PGHS-2 and PGHS-1, in murine osteoblastic MC3T3-E1 cells, which express both(More)
Prostaglandins are likely to play an important role in the physiologic and pathologic responses of skeletal tissue. They are potent agonists that can stimulate and inhibit bone resorption and formation. In vivo, the major effect of exogenous prostaglandins, particularly prostaglandin E2, is to stimulate resorption and formation. These effects appear to(More)
We examined the effect on osteoclast formation of disrupting the prostaglandin G/H synthase genes PGHS-1 and-2. Prostaglandin E(2) (PGE(2)) production was significantly reduced in marrow cultures from mice lacking PGHS-2 (PGHS-2(-/-)) compared with wild-type (PGHS-2(+/+)) cultures. Osteoclast formation, whether stimulated by 1,25-dihydroxyvitamin D(3)(More)
Induction of cyclooxygenase-2 (COX-2) is thought to be important for the anabolic effects of mechanical loading. The transcription factor Cbfa1/Runx2 is essential for osteoblastic differentiation. We examined the role of Cbfa1 in the fluid shear stress (FSS) induction of COX-2 in MC3T3-E1 cells stably transfected with a COX-2 promoter-luciferase reporter.(More)
Estrogen replacement therapy (ERT) prevents bone loss and fracture in early postmenopausal women, but its benefit for women over 70 yr of age has not been determined. We have examined the effect of a short course of ERT on biochemical markers of bone turnover in older women. Eleven women (mean age, 77 yr) were given conjugated estrogen (Premarin; 0.625(More)