bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mutations of the GNAS1 Gene, Stromal Cell Dysfunction, and Osteomalacic Changes in Non–McCune–Albright Fibrous Dysplasia of Bone
Authors: Bianco P. , Riminucci M. , Majolagbe A. , Kuznetsov S. A. , Collins M. T. , Mankani M. H. , Corsi A. , Bone H. G. , Wientroub S. , Spiegel A. M. , Fisher L. W. , Gehron ROBEY P. 
Published: April 2006

Abstract
Activating missense mutations of the GNAS1 gene, encoding the α subunit of the stimulatory G protein (Gs), have been identified in patients with the McCune–Albright syndrome (MAS; characterized by polyostotic fibrous dysplasia, café au lait skin pigmentation, and endocrine disorders). Because fibrous dysplasia (FD) of bone also commonly occurs outside of the context of typical MAS, we asked whether the same mutations could be identified routinely in non-MAS FD lesions. We analyzed a series of 8 randomly obtained, consecutive cases of non-MAS FD and identified R201 mutations in the GNAS1 gene in all of them by sequencing cDNA generated by amplification of genomic DNA using a standard primer set and by using a novel, highly sensitive method that uses a protein nucleic acid (PNA) primer to block amplification of the normal allele. Histologic findings were not distinguishable from those observed in MAS-related FD and included subtle changes in cell shape and collagen texture putatively ascribed to excess endogenous cyclic adenosine monophosphate (cAMP). Osteomalacic changes (unmineralized osteoid) were prominent in lesional FD bone. In an in vivo transplantation assay, stromal cells isolated from FD failed to recapitulate a normal ossicle; instead, they generated a miniature replica of fibrous dysplasia. These data provide evidence that occurrence of GNAS1 mutations, previously noted in individual cases of FD, is a common and perhaps constant finding in non-MAS FD. These findings support the view that FD, MAS, and nonskeletal isolated endocrine lesions associated with GNAS1 mutations represent a spectrum of phenotypic expressions (likely reflecting different patterns of somatic mosaicism) of the same basic disorder. We conclude that mechanisms underlying the development of the FD lesions, and hopefully mechanism-targeted therapeutic approaches to be developed, must also be the same in MAS and non-MAS FD.
Phenotypic Stability of Articular Chondrocytes In Vitro: The Effects of Culture Models, Bone Morphogenetic Protein 2, and Serum Supplementation
Authors: Stewart Matthew C. , Saunders Kathryn M. , Burton-Wurster Nancy , Macleod James N. 
Published: April 2006

Abstract
Numerous in vitro culture models have been developed for the investigation of chondrocyte and cartilage biology. In this study, we investigated the stability of the chondrocytic phenotype in monolayer, aggregate, pellet, and explant culture models and assessed the effects of recombinant human bone morphogenetic protein 2 (rhBMP-2) and serum supplementation on the phenotype in each model. Phenotypic effects were assessed by analyses of procollagen type II, aggrecan, (V+C)− fibronectin, and procollagen type I messenger RNA expression. In monolayer cultures, we noted a characteristic loss of procollagen type II and induction of procollagen type I expression. The aggregate and pellet culture models supported matrix protein gene expression profiles more reflective of in vivo levels. In explant cultures, expression of matrix protein genes was consistently depressed. Treatment with rhBMP-2 significantly increased the expression of procollagen type II and aggrecan in monolayer cultures; however, other models showed comparatively little response. Similarly, serum supplementation significantly down-regulated procollagen type II and aggrecan expression in monolayer cultures but had less effect on gene expression in the other models. Serum supplementation increased procollagen type I expression in monolayer and aggregate cultures. These results suggest that the influence of exogenous BMP-2 and serum on expression of chondrocyte-specific matrix protein genes is influenced by aspects of substrate attachments, cellular morphology, and/or cytoskeletal organization. Finally, the analyses of fibronectin expression suggest that V and C region alternative splicing in chondrocytes is linked to the establishment of a three-dimensional multicellular complex.
Variations in Three-Dimensional Cancellous Bone Architecture of the Proximal Femur in Female Hip Fractures and in Controls
Authors: Ciarelli T. E. , Fyhrie D. P. , Schaffler M. B. , Goldstein S. A. 
Published: April 2006

Abstract
Cubes of cancellous bone were obtained from proximal femora of women with hip fractures (n = 26) and from female cadaveric controls (n = 32) to compare architecture and mechanics between groups. Specimens were scanned on a microcomputed tomography system. Stereologic algorithms and model-based estimates were applied to the data to characterize the three-dimensional cancellous microstructure. Cubes were mechanically tested to failure to obtain mechanical properties. Specimens from control subjects had significantly higher bone volume fraction, trabecular number, and connectivity than specimens from patients with hip fractures; no difference in trabecular thickness was observed between groups. Both maximum modulus and ultimate stress were significantly higher in the control than in the fracture group, consistent with the higher bone volume found in the control group. No statistical differences in any of these architectural or mechanical variables were found when groups were matched for bone volume. Specimens from both patients with hip fractures and controls demonstrated strong relationships between trabecular number and bone volume fraction that were statistically equivalent, suggesting that for a given bone mass, both groups have the same overall number of trabeculae. However, there was an architectural difference between fracture and control groups in terms of the three-dimensional spatial arrangement of trabeculae. Fracture specimens had a significantly more anisotropic (oriented) structure than control specimens, with proportionately fewer trabecular elements transverse to the primary load axis, even when matched for bone volume. Relationships between mechanical and architectural parameters were significantly different between groups, suggesting that fracture and control groups have different structure-mechanics relationships, which we hypothesize may be a consequence of the altered three-dimensional structure between groups.
Human Myeloma Cells Promote the Recruitment of Osteoblast Precursors: Mediation by Interleukin-6 and Soluble Interleukin-6 Receptor
Authors: Karadag Abdullah , Scutt Andrew M. , Croucher Peter I. 
Published: April 2006

Abstract
Multiple myeloma is associated with the development of osteolytic bone disease characterized by a disruption to normal bone resorption and bone formation. Although studies have shown that myeloma cells produce factors that promote bone resorption little data are available examining the mechanism of decreased bone formation or the factors that mediate this effect. In the present study we describe a novel in vitro coculture system in which to investigate the effect of myeloma cells on osteoblast recruitment and differentiation. Under appropriate conditions mesenchymal stem cells were shown to differentiate into colonies of cells, a proportion of which show characteristics of osteoblasts, in that they express alkaline phosphatase activity and stain positively for collagen and calcium. The addition of the human myeloma cells JJN-3, RPMI-8226, or NCI-H929 to these cultures stimulated a significant increase in the total number of colonies (p &lt; 0.005) and the proportion of osteoblastic colonies (p &lt; 0.005). Media conditioned by these cells also were able to promote the formation of both total and osteoblastic colonies (p &lt; 0.005). The addition of an antibody against the interleukin-6 receptor (IL-6R) blocked myeloma cell and myeloma cell-conditioned media induced osteoblast recruitment (p &lt; 0.01). Furthermore, media conditioned by myeloma cells incubated with phorbol ester, which promotes IL-6R shedding, or a metalloproteinase inhibitor, which inhibits IL-6R shedding, were able to stimulate (p &lt; 0.005) and inhibit osteoblast recruitment (p &lt; 0.005), respectively. In addition, soluble IL-6R (sIL-6R) and IL-6 together, but not alone, were able to promote osteoblastic colony formation (p &lt; 0.01). Taken together these data show that myeloma cells promote osteoblast recruitment by release of sIL-6R from myeloma cells.
Interleukin-6 Gene Polymorphism Is Related to Bone Mineral Density During and After Puberty in Healthy White Males: A Cross-Sectional and Longitudinal Study
Authors: Lorentzon Mattias , Lorentzon Ronny , Nordström Peter 
Published: April 2006

Abstract
Bone mineral density (BMD) is under strong genetic control and is the major determinant of fracture risk. The cytokine interleukin-6 (IL-6) is an important regulator of bone metabolism and is involved in mediating the effects of androgens and estrogens on bone. Recently, a G/C polymorphism in position −174 of the IL-6 gene promoter was found. We investigated this genetic polymorphism in relation to BMD during late puberty and to peak bone mass, in healthy white males. We identified the IL-6 genotypes (GG, GC, and CC) in 90 boys, age 16.9 ± 0.3 years (mean ± SD), using polymerase chain reaction (PCR). BMD (g/cm2) at the femoral neck, lumbar spine, and total body was measured using dual energy X-ray absorptiometry. The volumetric BMD (vBMD; mg/cm3) of the lumbar spine was estimated. Differences in BMD in relation to the genotypes were calculated using analysis of variance (ANOVA). Subjects with the CC genotype had 7.9% higher BMD of the femoral neck (p = 0.03), 7.0% higher BMD of the lumbar spine (p &lt; 0.05), and 7.6% higher vBMD of the lumbar spine (p = 0.04), compared with their GG counterparts. Using multiple regression, the IL-6 genotypes were independently related to total body BMD (CC &gt; GG; p = 0.03), humerus BMD (CC &gt; GG; p &lt; 0.05), neck BMD (CC &gt; GG; p = 0.01), spine BMD (CC &gt; GG; p = 0.01), and spine vBMD (CC &gt; GG; p = 0.008). At age 19.3 ± 0.7 years (mean ± SD; 88 men) the IL-6 genotypes were still independent predictors for total body BMD (CC &gt; GG; p = 0.03), humerus BMD (CC &gt; GG; p = 0.03), spine BMD (CC &gt; GG; p = 0.02), and spine vBMD (CC &gt; GG; p = 0.003), while the IL-6 genotypes were not related to the increase in bone density seen after 2 years. We have shown that polymorphism of the IL-6 gene is an independent predictor of BMD during late puberty and of peak bone mass in healthy white men.
Calvariae from Fetal Mice with a Disrupted Igf1 Gene Have Reduced Rates of Collagen Synthesis but Maintain Responsiveness to Glucocorticoids
Authors: Woitge Henning W. , Kream Barbara E. 
Published: April 2006

Abstract
The goals of this study were to examine the role of insulin-like growth factor I (IGF-I) on bone formation and to test the hypothesis that the inhibitory effects of glucocorticoids on bone formation are independent of the IGF-I pathway. In serum-free organ cultures of 18-day fetal mouse calvariae derived from Igf1 null mice (Igf1−/−) and their wild-type (Igf1+/+) and heterozygous (Igf1+/−) littermates, we measured the incorporation of [3H]proline into collagenase-digestible protein (CDP) and noncollagen protein (NCP), percent collagen synthesis (PCS), the incorporation of [3H]thymidine into DNA, and messenger RNA (mRNA) levels of osteoblast markers in the presence or absence of dexamethasone. After 24 h of culture, calvariae of all genotypes had similar levels of PCS. However, after 48–96 h of culture, PCS was significantly lower in Igf1−/− calvariae compared with Igf1+/+ calvariae. Treatment of calvariae with 100 nM of dexamethasone for 48–96 h decreased PCS in all genotypes. After 72 h of culture, [3H]thymidine incorporation was similar in all genotypes and 100 nM dexamethasone caused a significant reduction in [3H]thymidine incorporation in all genotypes. Dexamethasone at 100 nM decreased α1(I)-collagen (Col1a1) mRNA and increased alkaline phosphatase, bone sialoprotein, and osteopontin mRNA in all genotypes after 72 h of culture. Type I IGF receptor mRNA levels were highest in Igf1−/− calvarial cultures. Dexamethasone at 100 nM increased Igf2 and type I IGF receptor mRNA levels in all genotypes. We conclude that one intact allele for Igf1 is sufficient to maintain normal rates of collagen synthesis in fetal mouse calvarial cultures. Moreover, the inhibitory effects of glucocorticoids on collagen synthesis and cell replication are at least partially independent of the IGF-I pathway in this model.
Spontaneous, But Not Induced, Puberty Permits Adequate Bone Mass Acquisition in Adolescent Turner Syndrome Patients
Authors: Carrascosa A. , Gussinyé M. , Terradas P. , Yeste D. , Audí L. , Vicens-Calvet E. 
Published: April 2006

Abstract
Lumbar L2-L4 bone mineral density (BMD) values were measured in 37 adolescent and young adult Turner syndrome patients. Nine had developed spontaneous puberty and had had regular menses since menarche (12.55 years ± 1.17 years) to the time of BMD evaluation (14.96 years ± 1.26 years). In the other 28, puberty was induced with increasing doses of oral ethinyl estradiol (2.5-10.0 μg/day, for 2 years) and later administration of estrogen/gestagen therapy up to the time of BMD evaluation. In 18, the adolescent group, menarche appeared at 14.68 years ± 0.63 years and BMD was evaluated at 17.77 years ± 0.70 years, and in the other 10, the young adult group, menarche appeared at 14.47 years ± 0.53 years and BMD was evaluated at 20.90 years ± 0.68 year. BMD values were in the normal range in those who had developed spontaneous puberty (Z score values, −0.24 ± 0.22) and in the osteopenia range in those in whom puberty was induced (Z score values, −2.09 ± 0.79 and −2.18 ± 0.32 for the adolescent and young adult groups, respectively) p &lt; 0.0001. Height Z score values were similar in all three groups (−3.45 ± 0.77, −3.15 ± 0.83, and −3.08 ± 0.33, respectively). No significant differences in calcium intake or physical activity were found among groups. Neither the karyotype distribution nor growth hormone (GH) therapy (five in the spontaneous puberty and six in the induced puberty groups had been treated for a 3.5- to 4.4-year period) explained the differences in BMD values. Because the main difference between groups was the availability of estrogens to bone tissue from infancy to menarche and of estrogens/gestagens from then on up to the time of BMD evaluation, our results suggest that normal gonadal function from infancy to adulthood may be required for adequate bone mass peaking. Early detection of osteopenia and improvement in general measures for adequate bone mass peaking (calcium intake and physical activity) should be considered mandatory in the health care of these patients.
More Broken Bones: A 4-Year Double Cohort Study of Young Girls With and Without Distal Forearm Fractures
Authors: Goulding A. , Jones I. E. , Taylor R. W. , Manning P. J. , Williams S. M. 
Published: April 2006

Abstract
Predictors of childhood fractures have not been investigated previously. This study was undertaken to determine whether a previous history of forearm fracture, low bone mineral density (BMD; both areal bone mineral density [aBMD, g/cm2] and volumetric bone mineral apparent density [BMAD, g/cm3]), or anthropometry, influence fracture risk in young girls. At baseline, two cohorts of girls, aged 3–15 years, were evaluated: 100 had recently broken a forearm (group 1) and 100 were fracture free (group 2). Four years later we restudied 170 of these girls (82 from group l and 88 from group 2). We now report the relationships of previous fracture history, baseline BMD (measured by dual-energy X-ray absorptiometry), baseline weight, and height to risk of new fracture. More new fractures occurred in group l (37 fractures in 24 girls) than in group 2 (8 fractures in 7 girls; p = 0.0007). The independent predictors for occurrence of a new fracture at any skeletal site in a multivariate model adjusting for age, weight, total body aBMD, and fracture history were previous fracture (hazard ratio [HR], 3.28; 95% CI, 1.41-7.64); age (HR per l-year increase, 0.91; 95% CI, 0.84-0.99); total body aBMD (HR per l SD decrease, 1.92; 95% CI, 1.31-2.81); and body weight (HR per l SD increase, 1.49; 95% CI, 1.06-2.08). Girls with two risk factors together had substantially greater fracture risk: previous fracture and low spinal BMAD (HR, 9.4; 95% CI, 2.8-32.0), previous fracture and high body weight (HR, 10.2; 95% CI, 2.8-37.6), or previous fracture and low total body aBMD (HR, 13.0; 95% CI, 3.9-43.1). We conclude that previous forearm fracture, low total body aBMD, low spinal BMAD, and high body weight each increase risk of new fractures within 4 years in young girls. Interventions to reduce the risk of fractures, particularly forearm fractures, in girls warrant further study.
Deficiency of the α-Subunit of the Stimulatory G Protein and Severe Extraskeletal Ossification
Authors: Eddy Mark C. , Jan de beur Suzanne M. , Yandow Suzanne M. , McAlister William H. , Shore Eileen M. , Kaplan Frederick S. , Whyte Michael P. , Levine Michael A. 
Published: April 2006

Abstract
Progressive osseous heteroplasia (POH) is a rare disorder characterized by dermal ossification beginning in infancy followed by increasing and extensive bone formation in deep muscle and fascia. We describe two unrelated girls with typical clinical, radiographic, and histological features of POH who also have findings of another uncommon heritable disorder, Albright hereditary osteodystrophy (AHO). One patient has mild brachydactyly but no endocrinopathy, whereas the other manifests brachydactyly, obesity, and target tissue resistance to thyrotropin and parathyroid hormone (PTH). Levels of the α-subunit of the G protein (Gsα) were reduced in erythrocyte membranes from both girls and a nonsense mutation (Q12X) in exon 1 of the GNAS1 gene was identified in genomic DNA from the mildly affected patient. Features of POH and AHO in two individuals suggest that these conditions share a similar molecular basis and pathogenesis and that isolated severe extraskeletal ossification may be another manifestation of Gsα deficiency.
A Skeletal Gene Database
Authors: Ho Nicola C. , Jia Libin , Driscoll Catherine C. , Gutter Emily M. , Francomano Clair A. , Drezner Marc K. 
Published: April 2006

Abstract
Systematic organization of documented data coupled with ready accessibility is of great value to research. Catalogs and databases are created specifically to meet this purpose. The Skeletal Gene Database evolves as part of the Skeletal Genome Anatomy Project (SGAP), an ongoing multi-institute collaborative effort, to study the functional genome of bone and other skeletal tissues. The primary objective of the Skeletal Gene Database is to create a contemporary list of skeletal-related genes, offering the following information for each gene: gene name, protein name, cellular function, disease(s) caused by mutation of the corresponding gene, chromosomal location, LocusLink number, gene size, exon/intron numbers, messenger RNA (mRNA) coding region size, protein size/molecular weight, Online Mendelian Inheritance in Man (OMIM) number of the gene, UniGene assignment, and PubMed reference. The database includes genes already known and published in the literature as well as novel genes not yet characterized but known to be expressed in skeletal tissue. It will be posted on the web for easy access and swift referencing. The data will be updated in tempo with current and future research, thereby providing an invaluable service to the scientific community interested in obtaining information on bone-related genes.
The Expression of Metalloproteinase-2, −9, and −14 and of Tissue Inhibitors-1 and −2 Is Developmentally Modulated During Osteogenesis In Vitro, the Mature Osteoblastic Phenotype Expressing Metalloproteinase-14
Authors: Filanti C. , Dickson G. R. , Di Martino D. , Ulivi V. , Sanguineti C. , Romano P. , Palermo C. , Manduca P. 
Published: April 2006

Abstract
During osteogenesis, in vitro, of tibial-derived rat osteoblasts (ROB) and derived clones, changes occur in the interactions of mature osteoblasts with the endogenous extracellular matrix (ECM) and these culminate in the formation of tridimensional nodules, which become sites of mineral deposition. We investigated if these changes might be mediated by remodeling of ECM, and we focused our study on the neutral metalloproteinases (MMPs), known agents of matrix remodeling, and on their tissue inhibitors (TIMPs). We report that during in vitro differentiation, osteoblasts express the secreted MMP-2 and −9 and the membrane gelatinase MMP-14. These, along with the tissue inhibitors TIMP-1 and −2, are developmentally regulated according to the maturation stage of osteoblasts. Their levels change in a similar association with osteoblast phenotypic maturation in different populations of ROB, which take different times to complete osteogenesis in vitro. MMP-14 expression coincides in both cell populations with the mature osteoblastic phenotype and is localized in the cells forming nodules. MMP-2 and −9 are expressed diffusely in the osteoblast population. Developmentally associated changes in the activation of MMP-2 are detected, associated in their timing with the expression of MMP-14 in both populations of ROB, and MMP-14 activates pro-MMP-2 in vitro. Expression of messenger RNAs (mRNAs) for the three MMPs increases up to the time of nodule formation. At this stage, TIMP-1 mRNA levels are lowest. TIMP-2 mRNA decreases throughout osteogenesis. In situ hybridization in 7-day-old rat tibias shows the strongest expression of MMP-14 among osteogenic cells, in lining osteoblasts on the newly formed trabeculae under the growth plate, and on the endosteal surface of cortical bone. Our data support the concept that the developmentally regulated expression of MMP-14 triggers localized proteolysis within the osteogenic population, concomitant in vitro to nodule formation.
Bisphosphonates Induce Breast Cancer Cell Death In Vitro
Authors: Fromigue Olivia , Lagneaux Laurence , Body Jean-Jacques 
Published: April 2006

Abstract
Breast cancer frequently spreads to bone and is almost always associated with osteolysis. This tumor-induced osteolysis is caused by increased osteoclastic bone resorption. Bisphosphonates are used successfully to inhibit bone resorption in tumor bone disease and may prevent development of new osteolytic lesions. The classical view is that bisphosphonates only act on bone cells. We investigated their effects on breast cancer cells using three human cell lines, namely, MCF-7, T47D, and MDA.MB.231, and we tested four structurally different bisphosphonates: clodronate, pamidronate, ibandronate, and zoledronate. We performed time course studies for each bisphosphonate at various concentrations and found that all four compounds induced a nonreversible growth inhibition in both MCF-7 and T47D cell lines in a time- and dose-dependent manner. The MDA.MB.231 cell line was less responsive. Bisphosphonates induced apoptosis in MCF-7 and cell necrosis in T47D cells. The inhibition of MCF-7 cell proliferation could be reverted almost completely by the benzyloxycarbonyl-Val-Ala-Asp(OMe)-fluoromethyl ketone (z-VAD-fmk) inhibitor of caspases, suggesting that the apoptotic process observed in the MCF-7 cell line is mediated, at least partly, by the caspase system. Caspase activity was little changed by bisphosphonates in T47D cells and the inhibitor of caspase did not modify bisphosphonates effects. In summary, we found that bisphosphonates inhibit breast cancer cell growth by inducing cell death in vitro. Such effects could contribute to the beneficial role of bisphosphonates in the treatment and the prevention of tumor-induced osteolysis.