bluuebunny/crossref_metadata_2025_split huggingface dataset:
Phorbol myristate acetate stimulates osteoclast formation in 1α, 25-dihydroxyvitamin D3-primed mouse embryonic calvarial cells by a Prostaglandin-dependent mechanism
Authors: Amano Shigeru , Hanazawa Shigemasa , Kawata Yasuhiro , Nakada Yuh , Miyata Yuhko , Kitano Shigeo 
Published: February 2010

Abstract
Our previous study provided a novel assay system utilizing devitalized bone slices for study of the differentiation of osteoclast progenitors into preosteoclasts and mature osteoclasts among calvarial cells of mouse embryos. Using this assay system, we examined the effect of phorbol myristate acetate (PMA) on osteoclast formation as assessed by the appearance of tartrate-resistant acid phosphatase (TRAP)-positive cells and bone resorption lacunae. PMA alone was directly unable to induce the appearance of TRAP-positive cells and bone resorption lacunae of calvarial bone cells of mouse embryos. However, PMA markedly stimulated increases in the number of TRAP-positive cells and area of the resorption lacunae of the calvarial cells when the bone cells were primed by 1α,25-(OH)2D3. This stimulatory effect of PMA was dose dependent. H-7, having relatively high affinity for protein kinase C, strongly inhibited in a dose-dependent fashion the stimulatory effect of PMA on the bone resorption of the hormone-primed calvarial cells. We also examined the involvement of prostaglandin in this stimulatory effect of PMA. Indomethacin, a cyclooxygenase inhibitor, markedly abolished the stimulatory effect of PMA on the bone resorption of the calvarial cells. PMA stimulated prostaglandin E2 (PGE2) production by the calvarial cells primed with 1α, 25-(OH)2D3 in a dose-dependent fashion. However, the PMA stimulation of the PGE2 production was significantly inhibited by H-7 and also by indomethacin. Furthermore, we observed that the addition of PGE2 to the calvarial cells primed with 1α, 25-(OH)2D3 for 1 or 3 days resulted in an increased number of TRAP-positive cells and increased bone resorption. This stimulatory effect of the exogenous PGE2 was also observed in the presence of indomethacin. These results strongly suggest that PMA stimulates osteoclast formation in 1α, 25-(OH)2D3-primed calvarial cells by a prostaglandin-dependent mechanism.
Metabolic bone disease in black teenagers with genu valgum or varum without radiologic rickets: A bone histomorphometric study
Authors: Dr. Schnitzler Christine M. , Pettifor John M. , Patel Deepak , Mesquita Julia M. , Moodley Gopal P. , Zachen Dianne 
Published: February 2010

Abstract
Calcium deficiency in black (African) children can cause rickets and osteomalacia with severe limb deformities. It is not known whether black teenagers with genu valgum or varum but without radiologic rickets suffer from a related disorder. To examine this question we studied 26 such patients by iliac crest bone biopsy and serum and urine biochemistry: 12 patients (46%) had osteopenia with normal or low bone turnover, 5 (19%) mildly increased bone turnover, 4 (15%) histologic hyperparathyroidism, 2 (8%) preosteomalacia, and 3 (12%) osteomalacia (with features of hyperparathyroidism). Radiographs did not reflect the severity of the bone disease. Serum calcium levels correlated inversely with eroded mineralized surface (p &lt; 0.001), osteoid surface (p &lt; 0.01), osteoid thickness (p &lt; 0.001), mineralization lag time (p &lt; 0.001), and 1,25-(OH)2 vitamin D (p &lt; 0.005), and 1,25-(OH)2 vitamin D correlated positively with osteoid surface (p &lt; 0.05), osteoid thickness (p &lt; 0.05), osteoid volume (p &lt; 0.01), eroded surface (p &lt; 0.05), and eroded mineralized surface (p &lt; 0.0005). Tubular reabsorption of phosphate and 25-OH vitamin D levels were normal, and 1,25-(OH)2 vitamin D levels were normal to high. This suggests that calcium deficiency may have caused the increase in bone turnover and the mineralization defects. The most severe osteomalacia was found in males aged 16–19 years. We cannot explain the cause of the osteopenia. We conclude that all patients had bone disease.
Specific activity of skeletal alkaline phosphatase in human osteoblast-line cells regulated by phosphate, phosphate esters, and phosphate analogs and release of alkaline phosphatase activity inversely regulated by calcium
Authors: Farley John R. , Hall Susan L. , Tanner Michael A. , Wergedal Jon E. 
Published: February 2010

Abstract
We assessed the significance of Ca and phosphate (Pi) as determinants of (1) the amount of skeletal alkaline phosphatase (ALP) activity in SaOS-2 (human osteosarcoma) cells and normal human bone cells, and (2) the release of ALP activity from the cells into the culture medium. After 24 h in serum-free BGJb medium containing 0.25–2 mM Pi, the specific activity of ALP in SaOS-2 cells was proportional to Pi concentration (r = 0.99, p &lt; 0.001). The Pi-dependent increase in ALP activity was time dependent (evident within 6 h) and could not be attributed to decreased ALP release, since Pi also increased the amount of ALP activity released (r = 0.99, p &lt; 0.001). Parallel studies with Ca (0.25–2.0 mM) showed that the amount of ALP activity released from SaOS-2 cells was inversely proportional to the concentration of Ca (r = −0.85, p &lt; 0.01). This effect was rapid (i.e., observed within 1 h) and could not be attributed to a decrease in the amount of ALP activity in the cells. Phase distribution studies showed that the effect of low Ca to increase ALP release reflected increases in the release of both hydrophilic ALP (i.e., anchorless ALP, released by phosphatidylinositol-glycanase activity) and hydrophobic ALP (i.e., phosphatidylinositol-glycan–anchored ALP, released by membrane vesicle formation). The range of Ca-dependent changes in ALP-specific activity was much smaller than the range of Pi-dependent changes. The observed correlation between skeletal ALP-specific activity and Pi was not unique to osteosarcoma cells or to Pi. Similar effects were seen in normal human bone cells in response to Pi (r = 0.99, p &lt; 0.001) and in SaOS-2 cells in response to a variety of Pi esters and analogs (e.g., β-glycero-Pi and molybdate). Further studies indicated that the effects of phosphoryl compounds on ALP-specific activity could not be correlated with effects on ALP reaction kinetics, cell proliferation, or acid phosphatase activity and that the β-glycero-Pi-dependent increase in ALP activity was blocked by cycloheximide but not actinomycin D. Together these data suggest that the function of skeletal ALP may be regulated by Pi and that Ca may be involved in ALP release.
Effect of cyclosporin A on bone mineral metabolism in experimental diabetes mellitus in the rat
Authors: Epstein Sol , Takizawa M. , Stein B. , Katz I.A. , Joffe I.I. , Romero D.F. , Liang X.G. , Li M. , Ke H.Z. , Jee W.S.S. , Jacobs T.W. , Berlin J. 
Published: February 2010

Abstract
Cyclosporin A (CsA) is widely used in diabetic transplant patients and early type I diabetes mellitus. Diabetes produces a low-turnover osteopenia, and CsA conversely induces high-turnover osteopenia in rats. We investigated whether CsA would exacerbate diabetic osteopenia. Four groups of 10-week-old male Sprague-Dawley rats (n = 11/group) were studied: On day −6, groups A and C received saline and groups B and D received intravenous streptozotocin (55 mg/kg) to induce diabetes. From day 0, groups A and B received CsA vehicle and C and D received CsA (15 mg/kg) by daily gavage. Rats were bled on days −6, 0, 11, and 22 for serum bone gla protein (BGP), 1-,25-(OH)2D, PTH, blood ionized Ca, and blood glucose determinations. Double tetracycline labeling was performed on days 9 and 20 for bone histomorphometry. After sacrifice on day 22, histomorphometric analysis was performed. Serum BGP, 1,25-(OH)2D, and PTH levels were significantly decreased in the diabetic alone (B) and diabetic plus CsA (D) groups and significantly increased in the CsA alone (group C). CsA alone (group C) induced cancellous bone loss by stimulated bone resorption. Cancellous bone loss in the diabetic alone rats (group B) was caused primarily by inhibited bone formation. No differences were found in cancellous bone mass, formation, or resorption parameters between diabetic alone (group B) and CsA-treated diabetic rats (group D). Neither CsA alone (group C) nor diabetic alone (group B) nor their combination affected cortical bone mass. CsA alone (group C) stimulated periosteal bone formation and endocortical bone resorption and inhibited endocortical formation, and diabetic alone (group B) inhibited both periosteal and endocortical bone formation. No parameters of tibial diaphyses in CsA-treated diabetic rats (group D) were different from diabetic alone. Thus the addition of CsA to the diabetic treated rats (group D) could not stimulate remodeling and appeared not to worsen significantly some of the alterations in bone formation and resorption. Possible explanations for this may be that CsA in vivo requires adequate levels of PTH, 1,25-(OH)2D, insulin, and perhaps growth factors to stimulate remodeling. The use of CsA in type I diabetic patients or in organ transplant recipients who remain diabetic after transplantation may in the short term not aggravate existing osteopenia based on these findings.
Murine osteoclasts and spleen cell polykaryons are distinguished by mRNA phenotyping
Authors: Tong Hong-Sheng , Sakai Dennis D. , Sims Stephen M. , Dixon Jeffrey S. , Yamin Moshe , Goldring Steven R. , Snead Malcolm L. , Minkin Cedric 
Published: February 2010

Abstract
To probe osteoclast gene expression, we combined the techniques of cell microisolation and RT-PCR to develop a novel and sensitive method for the isolation and mRNA phenotyping of small numbers of authentic osteoclasts and spleen cell polykaryons. Using this method we report (1) direct evidence for the presence of calcitonin receptor mRNA in osteoclasts, (2) confirmation of the recent finding of osteopontin mRNA in osteoclasts, and (3) demonstration that the specific expression of mRNA for tartrate-resistant acid phosphatase, carbonic anhydrase II, calcitonin receptor, and osteopontin enable one to distinguish the osteoclast from the morphologically similar and developmentally related spleen cell polykaryon. We also show that mRNA associated with the osteoblast phenotype, such as alkaline phosphatase, osteocalcin, and type I collagen, are absent in osteoclasts. This is the first report in which such an approach has been used successfully to distinguish the mRNA expression pattern of an authentic osteoclast from a macrophage polykaryon, and as such it should provide an important new tool for evaluating the results of various cell culture model systems designed to examine the origin and ontogeny of osteoclasts. Our results also indicate that these procedures can be used as an alternative to in situ hybridization methods for the cell-specific localization of specific mRNA in a mixed cell preparation and for colocalization of multiple mRNA species to a single cell type.
Production and release of matrix vesicles in the cell processes of TPA-treated human osteoblast-like cells
Authors: Ringbom-Anderson Tove , Jäntti Jussi , Åkerman Karl E.O. 
Published: February 2010

Abstract
At the onset of the mineralization of bone, small membranous matrix vesicles are often observed. The information available on the production and release of these vesicles is limited. When treated with 10–20 nM of the phorbol ester 12-O-tetradecanoyl-phorbol-13-acetate (TPA), the human osteosarcoma cell line U-2 OS developed long cytoplasmic processes connecting adjacent cells. SEM and TEM show that TPA triggers a production and release of matrix vesicle-like membrane vesicles, mainly from the cellular processes. Tetracycline HC1 was used to label intracellular bound calcium. The tetracycline HC1 label was primarily localized to the end-feet of the cytoplasmic processes, indicating that these contain high concentrations of Ca2+, and to endoplasmic reticulum-like structures in the cell bodies. Together with our previous demonstration of the release of alkaline phosphatase-containing vesicles into the culture medium (Ringbom-Anderson T, Åkerman KEO 1992 Calcif Tissue Int 50:533–540), the results presented here indicate that TPA induces a rapid induction of the primary steps of mineralization in U-2 OS osteosarcoma.
Improved assessment of lumbar vertebral body strength using supine lateral dual-energy X-ray absorptiometry
Authors: Myers Barry S. , Arbogast Kristy B. , Lobaugh Bruce , Harper Kristine D. , Richardson William J. , Drezner Marc K. 
Published: February 2010

Abstract
Clinical and biomechanical investigations indicate that assessment of vertebral body bone mineral density (BMD) by anteroposterior dual-energy x-ray absorptiometry (DXA) is a useful index of vertebral body strength and fracture risk in osteoporosis. However, inclusion of non-force-bearing and small-force-bearing mineralized structures, such as the posterior elements and aortic calcifications, in the measurement of anterior BMD obscures the assessment of vertebral body mass by this technique. Indeed, such interference is particularly severe in the presence of posterior element degeneration or previous spinal surgery. Recent anatomic studies illustrate that the lateral view provides unobstructed visualization of the L3, L4, and possibly L2 vertebral bodies, suggesting that supine lateral BMD may more accurately assess vertebral body fracture risk. We evaluated this hypothesis in a blinded study using human cadaver spines to compare the value of supine lateral and anteroposterior BMD in assessing vertebral body fracture force, average compressive stress, maximum stored strain energy, and strain at failure. Both measures of BMD significantly correlate with these biomechanical measures. However, statistical comparison of the methods using multiple and stepwise regression reveals that supine lateral BMD provides a better assessment of the vertebral body fracture properties than anteroposterior BMD. The enhanced predictive value of supine lateral BMD occurs because of the variable contribution of posterior element mineral to the anteroposterior BMD measurement. Evaluation to test the utility of supine lateral BMD for the assessment of fracture risk and a fracture threshold in patients with osteoporosis is therefore recommended.
Hereditary hyperphosphatasia: 20 year follow-up and response to disodium etidronate
Authors: Singer Frank , Siris Ethel , Shane Elizabeth , Dempster David , Lindsay Robert , Parisien May 
Published: February 2010

Abstract
We provide a 20 year follow-up of a family with three siblings affected by hereditary hyperphosphatasia (HH). An iliac crest bone biopsy was performed on one of the siblings following double-tetracycline labeling, with results reported quantitatively in a standard histomorphometric format. Biochemical parameters of disease activity were monitored in the patient before and after treatment with oral etidronate disodium, 20 mg/kg/day taken for 5 weeks. Biochemical evidence of intense disease activity continued 20 years after the initial diagnosis of HH in the sibling studied. His bone biopsy specimen also revealed extremely high bone turnover but low cancellous bone volume and osteoclasts unlike those found in Paget's disease. Treatment with etidronate disodium resulted in a temporary 40% reduction in serum alkaline phosphatase and 24 h urine hydroxyproline excretion, with reduction in serum osteocalcin from two times the upper limit of normal to a subnormal level. We conclude that disease activity in HH can continue unabated for two decades. Our bone biopsy finding of low cancellous bone volume, the consistent lack of pagetic-looking osteoclasts in our and other studies, plus the clinical features of HH (childhood onset and extremely diffuse disease with gross skeletal deformation) serve to distinguish HH from Paget's disease. Bisphosphonates may be of value in treating HH.
Family history of osteoporosis and bone mineral density at the axial skeleton: The rancho bernardo study
Authors: Soroko Sharon B. , Barrett-Connor Elizabeth , Edelstein Sharon L. , Kritz-Silverstein Donna 
Published: February 2010

Abstract
To determine whether a family history of osteoporosis identifies individuals with low bone mineral density (BMD), we studied 1477 white elderly (aged 60–89 years), noninstitutionalized ambulatory men (n = 600) and women (n = 877) from the Rancho Bernardo, California cohort. Family history data on biologic parents and full sisters were obtained by questionnaire. BMD of the lumbar spine and hip was measured using dual-energy x-ray absorptiometry. After adjustment for age, body mass index, history of cigarette smoking, thiazide use, and estrogen use, men and women with a family history of osteoporosis had lower BMD than those with a negative family history. In men, a positive family history was associated with lower BMD at the hip (p = 0.01), whereas in women a significant association was observed for the spine (p = 0.02). BMD decreased in a stepwise fashion with an increasing number of family members with a history of osteoporosis. Analysis of the effect of parental history of osteoporosis on BMD showed a significant relation between paternal (but not maternal) history and lumbar spine BMD in both sexes and a significant relation between maternal (but not paternal) history and hip BMD only in men. The relative risk of having categoric osteopenia was highest in those whose fathers had a history of osteoporosis (RR 2.16, 95% CI = 1.38–3.37). A similar association was found for subjects with fractures. These results were not explained by differential awareness of family history in individuals with known osteoporosis, because the prevalence of family history was unrelated to personal history of osteoporosis in men and only weakly related in women. The positive predictive value of family history as an indicator of categorically defined low bone density was 22% in men and 24% in women, although in women this value increased to 33% when father's history alone was considered. The negative predictive value of overall family history was 65% in men and 81% in women. Overall, these data suggest that clinicians who ask patients about family history of osteoporosis should ask about both parents.
Stimulation of prostaglandin e2 production by interleukin-1α and transforming growth factor α in osteoblastic MC3T3-E1 cells
Authors: Harrison J.R. , Lorenzo J.A. , Kawaguchi H. , Raisz L.G. , Pilbeam C. 
Published: February 2010

Abstract
The mechanism by which interleukin-1 (IL-1) and transforming growth factor α (TGF-α) regulate prostaglandin synthesis has been examined in the clonal mouse osteoblastic cell line MC3T3-E1. Cells were grown in DMEM containing 10% fetal calf serum. Prostaglandin E2 (PGE2) production was determined by radioimmunoassay or by prelabeling cells with [H]arachidonic acid, followed by high-performance liquid chromatography (HPLC) analysis of the labeled products released into the medium. Prostaglandin G/H synthase (PGHS) mRNAs were quantified by northern blot analysis using [32P]labeled cDNA probes. By HPLC, PGE2 was the major prostanoid produced under basal or stimulated conditions. No release of thromboxane or 6-keto-PGF1α into the medium was detected. PGE2 production was stimulated approximately 7- to 14-fold by IL-1 (1 ng/ml) and 3- to 8-fold by TGF-α (30 ng/ml) after 24 h. In combination, however, IL-1 and TGF-α caused a synergistic 37- to 71-fold increase in PGE2 accumulation. PGHS-1 mRNA levels were maximally increased approximately 2- to 3-fold by IL-1 and 1.5 to 2.5-fold by TGF-α after 24 h; the combination of IL-1 and TGF-α produced only an additive 3- to 6-fold increase. Western blotting revealed a corresponding 3-fold increase in immunoreactive PGHS-1 protein in response to combined IL-1 and TGF-α. PGHS-2 mRNA was increased 1.4-fold by TGF-α at 1 h, and the combination of IL-1 and TGF-α caused a 1.7-fold increase. After 3.5 h, IL-1 caused a dramatic induction of PGHS-2 mRNA levels but TGF-α alone no longer had an effect. However, the combination of IL-1 and TGF-α produced an increase in PGHS-2 mRNA levels that was twice that of IL-1 alone. The effects of IL-1 and TGF-α on the release of preincorporated [H]arachidonic acid from membrane phospholipid stores were examined at early time points in the presence of indomethacin. After 1 h, arachidonic acid release was enhanced 3-fold by IL-1, 1.5-fold by TGF-α, and 12-fold by IL-1 and TGF-α in combination. In conclusion, the synergistic actions of IL-1 and TGF-α on PGE2 synthesis in MC3T3-E1 cells involve multiple regulatory sites, including stimulation of de novo PGHS-1 and PGHS-2 synthesis and an early mobilization of arachidonic acid from phospholipid stores.
Immunolocalization of osteopontin, osteocalcin, and dentin sialoprotein during dental root formation and early cementogenesis in the rat
Authors: Bronckers Antonius L.J.J. , Farach-Carson Mary C. , Van Waveren Erwin , Butler William T. 
Published: February 2010

Abstract
Using immunohistochemical methods we studied the tissue localization of the extracellular matrix proteins osteopontin (OPN), osteocalcin (OC), and dentin sialoprotein (DSP) during the formation of acellular and cellular cementum in newly born rats. In the layer of acellular cementum of developing incisor and molar teeth we found a very strong staining for OPN but not for DSP or OC. Many cells immediately adjacent to acellular cementum and PDL cells were also positive for OPN but not for DSP or for OC. In contrast, cellular cementum in molar teeth stained strongly for OPN and OC but not for DSP. Consistent with these observations, the cells engaged in the formation of cellular cementum (cementoblasts and cementocytes) reacted strongly for OPN and OC but not for DSP. In advanced stages of dentinogenesis, both crown and root odontoblasts and dentin stained for OPN, OC, and DSP. Cells and matrices of surrounding alveolar bone stained for OPN and OC but not for DSP. We conclude that cementoblasts and cementocytes of cellular cementum produce OPN and OC but not DSP and thus express an osteoblast-like, not an odontoblast-like, phenotype. The cells responsible for the production of acellular cementum are likely cells of the PDL in close contact with the dental root surface. These fibroblast-like cells express OPN but not OC or DSP and accordingly express only a partial osteoblastic phenotype.