bluuebunny/crossref_metadata_2025_split huggingface dataset:
Collagenase-3 (MMP-13) and Integral Membrane Protein 2a (Itm2a) are Marker Genes of Chondrogenic/Osteoblastic Cells in Bone Formation: Sequential Temporal, and Spatial Expression of Itm2a, Alkaline Phosphatase, MMP-13, and Osteocalcin in the Mouse
Authors: Tuckermann Jan P. , Pittois Karen , Partridge Nicola C. , Merregaert Joseph , Angel Peter 
Published: April 2006

Abstract
Endochondral bone formation requires the action of cells of the chondrocytic and osteoblastic lineage, which undergo continuous differentiation during this process. To identify subpopulations of resting, proliferating, and hypertrophic chondrocytes and osteoblasts involved in bone formation, we have identified here two novel marker genes present in endochondral and intramembranous ossification. Using Northern blot analysis and in situ hybridization on parallel sections of murine embryos and bones of newborn mice we compared the expression pattern of the recently cloned Itm2a and MMP-13 (collagenase-3) genes with that of established marker genes for bone formation, such as alkaline phosphatase (ALP), osteocalcin (OC), and collagen type X, during endochondral and intramembranous ossification. During embryonic development expression of Itm2a and ALP was detectable at midgestation (11.5 days postcoitum [dpc]) and increased up to 16.5 dpc. MMP-13 and OC expression started at 14.5 dpc and 16.5 dpc, respectively. This temporal expression was reflected in the spatial distribution of these markers in the growth plate of long bones. In areas undergoing endochondral ossification Itm2a expression was found in chondrocytes of the resting and the proliferating zones. Expression of ALP and MMP-13 are mutually exclusive: ALP transcripts were found only in collagen type X positive hypertrophic chondrocytes of the upper zone. MMP-13 expression was restricted to chondrocytes of the lower zone of hypertrophic cartilage also expressing collagen type X. In osteoblasts involved in endochondral and intramembranous ossification Itm2a was not present. ALP, MMP-13, and OC were mutually exclusively expressed in these cells suggesting a differentiation-dependent sequential expression of ALP, MMP-13, and OC. The identification of the continuum of sequential expression of Itm2a, ALP, MMP-13, and OC will now allow us to establish a series of marker genes that are highly suitable to characterize bone cells during chondrocytic and osteoblastic differentiation in vivo.
Cellular Localization of Neprilysin in Mouse Bone Tissue and Putative Role in Hydrolysis of Osteogenic Peptides
Authors: Ruchon Andréa Frota , Marcinkiewicz Mieczyslaw , Ellefsen Kim , Basak Ajoy , Aubin Jane , Crine Philippe , Boileau Guy 
Published: April 2006

Abstract
The regulation of osteoblast and osteoclast metabolism is mediated by both hormones and local bone peptide factors. Peptides and hormones are under control of membrane peptidases such as Neprilysin (NEP). NEP is a widely distributed cell-surface zinc-metallopeptidase that is involved in the regulation of several important physiological processes by controlling the half-life of bioactive peptides. Although NEP is known to be present in skeletal tissues, neither its cellular localization nor its function have been established. To address this question, we examined NEP distribution in bones of postnatal mouse. In situ hybridization (ISH) and immunohistochemistry showed that NEP messenger RNA (mRNA) and protein are associated with bone-forming cells including presumptive osteoblast precursors, preosteoblasts, osteoblasts, and osteocytes. NEP levels in newborn and adult mice bones also were compared by immunoblotting. Higher amounts of NEP immunoreactivity were observed in newborn as compared with adult bones, suggesting a relationship between NEP expression and bone growth. To further explore this hypothesis, we monitored in vitro NEP proteolytic activity using a series of synthetic osteogenic peptides such as parathyroid hormone-related peptide 1–43 (PTHrP1–34), osteostatin (PTHrP107–139), osteogenic growth peptide (OGP), calcitonin, α-calcitonin gene-related peptide (α-CGRP), and PTH1–34. Except for PTH1–34, all peptides were found to be NEP substrates.
Estrogen Agonist (Zeranol) Treatment in a Castrated Male Lamb Model: Effects on Growth and Bone Mineral Accretion
Authors: Chanetsa F. , Dr. Hillman L. S. , Thomas M. G. , Keisler D. H. 
Published: April 2006

Abstract
The mechanism of estrogen's action on bone mineralization in children has received little attention. Our objective was to determine the effect of time (developmentally) and duration of exposure to an estrogen agonist (zeranol) on bone growth and mineralization using a castrated male lamb model. At birth, 40 male lambs were castrated and within 14 days of birth (day = 0) they were assigned (n = 10 per group) to age-matched control lambs (C-AGE) or to receive a 12.5-mg zeranol implant as follows: E-0, implanted on days 0, 45, 90, and 135; E-90, implanted on days 90 and 135; and E-0,90, implanted on days 0, 90, and 135. Lambs were studied for 163 days. Serum was collected on days 28, 73, 118, 135, and 163 and analyzed for minerals (Ca, P, and Mg), markers of bone remodeling (bone alkaline phosphatase [ALP] and tartrate resistant acid phosphatase [TRAP]), 1,25-dihydroxyvitamin D [1,25(OH)2D], growth hormone (GH), and insulin-like growth factor I (IGF-I). Whole-body bone mineral content (BMC), bone mineral density (BMD), fat mass, and lean mass were determined by dual energy X-ray absorptiometry (DEXA) on days 28, 73, 118, and 163. There was a linear increase in growth at all time points. Whole-body BMC, weight, and lean mass of C-AGE and E-90 lambs were less than E-0, and E-0,90 lambs at all time points. Whole-body BMD of C-AGE and E-90 lambs was less than E-0 and E-0,90 lambs at 28 days and 73 days; however, after implantation at day 90 whole-body BMD of E-90 lambs was similar to E-0 and E-0,90 lambs at day 118 and day 163 and all three were greater than C-AGE lambs. There was no effect of treatment on calcium absorption, serum minerals, hormones, or markers of bone remodeling. We conclude from these data that treatment of growing castrated lambs with an estrogen agonist from birth augments growth, whereas delaying estrogen agonist treatment does not facilitate growth but appears to augment bone mineral accretion. We suggest these observations may have clinical relevance, and deserve consideration when treating children with delays in growth and bone mineral accretion.
Bone Structure in Patients with Low Bone Mineral Density With or Without Vertebral Fractures
Authors: Oleksik Anna , Ott Susan M. , Vedi Shobna , Bravenboer Nathalie , Compston Juliet , Lips Paul 
Published: April 2006

Abstract
Vertebral fractures (VFX) are caused by low bone mass and microstructural deterioration of bone tissue. The latter is not well defined. We investigated bone structure in transiliac biopsy specimens from 88 volunteers. Biopsy specimens were obtained at baseline in the Multiple Outcomes of Raloxifene Evaluation trial, a prospective study in osteoporotic (BMD ≤ −2.5 T score) postmenopausal women without or with VFX on standardized lateral spinal radiographs. Bone biopsy specimens were embedded in methylmethacrylate (MMA). Histomorphometry was done in 8 μm (U.S.A.) or 5 μm (Europe) Goldner stained sections. Vertebral fracture status (yes/no) was the outcome variable in logistic regression models adjusted for age and biopsy specimen origin (U.S.A. vs. Europe). Patients with and without VFX (26/62) were similar regarding age (69.2 ± 5.2 years vs. 67.3 ± 6.7 years), bone volume (BV/TV; 17.7 ± 4.7% vs. 19.0 ± 5.8%), and bone surface (BS/TV; 2.7 ± 0.6 mm2/mm3 vs. 2.8 ± 0.6 mm2/mm3). A lower cortical thickness (C.Th; 652 ± 267 μm vs. 822 ± 325 μm), total strut length (TSL; 826 ± 226 μm/mm2 vs. 922 ± 256 μm/mm2), node-to-loop (Nd-Lp) strut length (10.1 ± 10.3% vs. 15.0 ± 13.6%), together with a higher node-to-terminus (Nd-Tm) strut length (45.6 ± 9.7% vs. 39.1 ± 9.3%) were each associated with prevalent VFX (0.01 &lt; p &lt; 0.10). Differences in BV/TV did not explain these associations. In conclusion, cortical thinning and disruption of trabecular lattice are possible pathogenic mechanisms in patients with VFX.
Hormonal and Biochemical Parameters and Osteoporotic Fractures in Elderly Men
Authors: Dr. Center Jacqueline R. , Nguyen Tuan V. , Sambrook Philip N. , Eisman John A. 
Published: April 2006

Abstract
Low testosterone has been associated with hip fracture in men in some studies. However, data on other hormonal parameters and fracture outcome in men is minimal. This study examined the association between free testosterone (free T) estradiol (E2), sex hormone-binding globulin (SHBG), 25-hydroxyvitamin D [25(OH)D], parathyroid hormone (PTH), insulin-like growth factor I (IGF-I), and fracture in 437 elderly community-dwelling men. Age, height, weight, quadriceps strength, femoral neck bone mineral density (FN BMD), and fracture data (1989–1997) also were obtained. Fractures were classified as major (hip, pelvis, proximal tibia, multiple rib, vertebral, and proximal humerus) or minor (remaining distal upper and lower limb fractures). Fifty-four subjects had a fracture (24 major and 30 minor). There was no association between minor fractures and any hormonal parameter. Risk of major fracture was increased 2-fold for each SD increase in age, decrease in weight and height, and increase in SHBG, and risk of major fracture was increased 3-fold for each SD decrease in quadriceps strength, FN BMD, and 25(OH)D (univariate logistic regression). Independent predictors of major fracture were FN BMD, 2.7 (1.5–4.7; odds ratio [OR]) and 95% confidence interval [CI]); 25(OH)D, 2.8 (1.5–5.3); and SHBG, 1.7 (1.2–2.4). An abnormal value for three factors resulted in a 30-fold increase in risk but only affected 2% of the population. It is not immediately apparent how 25(OH)D and SHBG, largely independently of BMD, may contribute to fracture risk. They may be markers for biological age or health status not measured by methods that are more traditional and as such may be useful in identifying those at high risk of fracture.
Posterior-Anterior and Lateral Dual-Energy X-Ray Absorptiometry for the Assessment of Vertebral Osteoporosis and Bone Loss Among Older Men
Authors: Zmuda Joseph M. , Cauley Jane A. , Glynn Nancy W. , Finkelstein Joel S. 
Published: April 2006

Abstract
Lateral spine dual-energy x-ray absorptiometry (DXA) selectively measures the trabecular-rich vertebral bodies without the contributions of the cortical-rich posterior elements of the spine and is less affected by spinal degenerative disease than posterior-anterior DXA. We tested whether lateral DXA detects vertebral osteoporosis more often and is more sensitive to age-related bone loss than posterior-anterior DXA in 193 healthy, community-dwelling men aged 51–81 years (mean ± SD; 67 ± 8 years). All men had supine lateral, posterior-anterior, and proximal femur DXA scans on a Hologic QDR 2000 densitometer. A subset (n = 102) had repeat scans after 4 years to determine annualized rates of change in bone mineral density (BMD). Age was inversely and significantly associated with BMD in the midlateral (r = −0.27) and lateral (r = −0.24) but not posterior-anterior (r = 0.04) projections. Midlateral (−1.43 ± 3.48% per year; p = 0.0001), lateral (−0.27 ± 1.68% per year; p = 0.12), and hip (−0.19 ± 1.02% per year; p = 0.06) BMD decreased, whereas posterior-anterior BMD increased (0.73 ± 1.11% per year; p = 0.0001) during follow-up. When compared with normal values in 43 men aged 21–42 years, mean T scores were significantly lower with lateral (−1.47 ± 1.32) and midlateral (−1.57 ± 1.36) than posterior-anterior (−0.12 ± 1.30; p &lt; 0.0001) DXA. Only 2.6% of the older men were considered osteoporotic (T score ≤ −2.5) at the posterior-anterior spine, whereas 11.0% were osteoporotic at the femoral neck, 22.5% at the lateral spine, and 24.6% were osteoporotic at the midlateral spine. We conclude that supine lateral DXA identifies considerably more men as osteoporotic and is more sensitive to age-related bone loss than posterior-anterior DXA. Spinal osteoporosis may represent a substantially greater health problem among older men than previously recognized.
ADAM8: A Novel Osteoclast Stimulating Factor
Authors: Choi Sun Jin , Han Je-Ho , Roodman G. David 
Published: April 2006

Abstract
We used polymerase chain reaction (PCR)-selective complementary DNA (cDNA) subtraction hybridization with an immortalized murine osteoclast (OCL) precursor cell line to identify genes that are highly expressed in OCLs compared with OCL precursors and which may be involved in the OCL differentiation process. ADAM8 was one of the 50 genes identified. ADAM (a disintegrin and metalloproteinase) peptides are membrane-bound proteins that can act as cell-to-cell and cell-to-matrix adhesion molecules, degrade the extracellular matrix, and play a role in tissue morphogenesis. Addition of antisense (AS) S-oligonucleotides for ADAM8 (1-10 nM) to mouse bone marrow cultures treated with 10−9 M 1,25-dihydroxyvitamin D3 [1,25-(OH)2D3] significantly inhibited OCL formation compared with treatment with the control S-oligonucleotide. Furthermore, conditioned media from 293 cells transiently transfected with a secretable form of the ADAM8 cDNA increased OCL formation in a dose-dependent manner. In addition, treatment of OCLs with soluble ADAM8 conditioned media significantly increased pit formation per dentin slice compared with control OCLs. Time course studies indicated that ADAM8 increased OCL formation only when it was present during days 4-7 of the 7-day culture period. Structural analysis, using truncated constructs of ADAM8, showed that the cysteine-rich/disintegrin domain was responsible for its OCL stimulatory activity. Western blot analysis confirmed that the soluble form of ADAM8 is present in normal marrow cultures. These data suggest that ADAM8 plays an important role in OCL formation and acts primarily at the later stages of OCL differentiation.
Role of N-Cadherin and Protein Kinase C in Osteoblast Gene Activation Induced by the S252W Fibroblast Growth Factor Receptor 2 Mutation in Apert Craniosynostosis
Authors: Lemonnier Jérome , Haÿ Eric , Delannoy Philippe , Lomri Abderrahim , Modrowski Dominique , Caverzasio Joseph , Marie Pierre J. 
Published: April 2006

Abstract
Apert (Ap) syndrome is characterized by premature cranial suture ossification caused by fibroblast growth factor receptor 2 (FGFR-2) mutations. We studied the role of cadherins and signaling events in the phenotypic alterations induced by the Ap FGFR-2 S252W mutation in mutant immortalized fetal human calvaria osteoblasts. The FGFR-2 mutation caused increased expression of the osteoblast markers alkaline phosphatase (ALP), type 1 collagen (COLIA1), and osteocalcin (OC) in long-term culture. The mutation also increased cell-cell aggregation, which was suppressed by specific neutralizing anti-N- and anti-E-cadherin antibodies. Mutant osteoblasts showed increased N- and E-cadherin, but not N-cell adhesion molecule (N-CAM) messenger RNA (mRNA) and protein levels. This was confirmed in vivo by the abundant immunoreactive N- and E-cadherins in preosteoblasts in the Ap suture whereas N-CAM and α- and β-catenins were unaffected. Neutralizing anti-N-cadherin antibody or N-cadherin antisense (AS) oligonucleotides but not anti-E-cadherin antibody or AS reduced ALP activity as well as ALP, COLIA1, and OC mRNA overexpression in mutant osteoblasts. Analysis of signal transduction revealed increased phospholipase Cγ (PLCγ) and protein kinase Cα (PKCα) phosphorylation and increased PKC activity in mutant cells in basal conditions. Inhibition of PKC by calphostin C or the PKCα-specific inhibitor Gö6976 suppressed the increased N-cadherin mRNA and protein levels as well as the overexpression of ALP, COLIA1, and OC mRNA in mutant cells. Thus, N-cadherin plays a role in the activation of osteoblast differentiation marker genes in mutant osteoblasts and PKCα signaling appears to be involved in the increased N-cadherin and osteoblast gene expression induced by the S252W FGFR-2 mutation in human osteoblasts.
Variations in Site and Levels of Expression of Chondrocyte Nucleotide Pyrophosphohydrolase with Aging
Authors: Masuda Ikuko , Iyama Ken-Ichi , Halligan Brian D. , Barbieri Joseph T. , Haas Arthur L. , Mccarty Daniel J. , Ryan Lawrence M. 
Published: April 2006

Abstract
The aim of this study was to identify changes in cartilage intermediate layer protein/nucleotide pyrophosphohydrolase (CILP/NTPPH) expression in articular cartilage during aging. Adult (3-4 years old) and young (7-10 days old) porcine articular hyaline cartilage and fibrocartilage were studied by Northern blot analysis, in situ hybridization, and immunohistochemistry using a complementary DNA (cDNA) probe encoding porcine CILP/NTPPH and antibody to a synthetic peptide corresponding to a CILP/NTPPH sequence. Northern blot analysis of chondrocytes showed lower expression of CILP/NTPPH messenger RNA (mRNA) in young cartilage than in adult cartilage. In adult cartilage, extracellular matrix from the surface to the middeep zone was immunoreactive for CILP/NTPPH, especially in the pericellular matrix surrounding the middeep zone chondrocytes. In young cartilage, chondrocytes were moderately immunoreactive for CILP/NTPPH throughout all zones except the calcified zone. The matrix of young cartilage was negative except in the superficial zone. In young cartilage, CILP/NTPPH mRNA expression was undetectable. In adult cartilage, chondrocytes showed strong mRNA expression for CILP/NTPPH throughout middeep zones. Protein and mRNA signals were not detectable below the tidemark. CILP/NTPPH secretion into matrix around chondrocytes increases with aging. In this extracellular site it may generate inorganic pyrophosphate and contribute to age-related calcium pyrophosphate dihydrate crystal deposition disease.
Colocalization of Noggin and Bone Morphogenetic Protein-4 During Fracture Healing
Authors: Yoshimura Yasuo , Nomura Shintaro , Kawasaki Satoshi , Tsutsumimoto Takahiro , Shimizu Tominaga , Takaoka Kunio 
Published: April 2006

Abstract
The regulation of callus formation during fracture repair involves the coordinate expression of growth factors and their receptors. This article describes the temporal and spatial expression of noggin gene, an antagonist to bone morphogenetic protein (BMP), during the fracture repair process. Noggin expression was examined by means of Northern blotting and in situ hybridization and compared with the expression pattern of BMP-4 in a model of fracture repair in adult mice. Expression levels of noggin messenger RNA (mRNA) were enhanced in the early phase of fracture callus formation. The localization of the noggin mRNA was similar to that of BMP-4 mRNA. Distinct noggin mRNA signals were located predominantly in cells lining the periosteum and the cortical endosteum near the fracture site at 2 days after fracture. At 5, 10, and 21 days after fracture, noggin mRNA was detected in the chondrocytes and osteoblasts in the newly formed callus. The pattern of localization was indistinguishable from that of BMP-4. These results suggest that the noggin/BMP-4 balance could be an important factor in the regulation of callus formation during fracture healing.
Classification of Osteoporosis Based on Bone Mineral Densities
Authors: Lu Ying , Genant Harry K. , Shepherd John , Zhao Shoujun , Mathur Ashwini , Fuerst Thomas P. , Cummings Steven R. 
Published: April 2006

Abstract
In this article we examine the role of bone mineral density (BMD) in the diagnosis of osteoporosis. Using information from 7671 women in the Study of Osteoporotic Fractures (SOF) with BMD measurements at the proximal femur, lumbar spine, forearm, and calcaneus, we examine three models with differing criteria for the diagnosis of osteoporosis. Model 1 is based on the World Health Organization (WHO) criteria using a T score of −2.5 relative to the manufacturers' young normative data aged 20-29 years, with modifications using information from the Third National Health and Nutrition Examination Survey (NHANES). Model 2 uses a T score of −1 relative to women aged 65 years at the baseline of the SOF population. Model 3 classifies women as osteoporotic if their estimated osteoporotic fracture risk (spine and/or hip) based on age and BMD is above 14.6%. We compare the agreement in osteoporosis classification according to the different BMD measurements for the three models. We also consider whether reporting additional BMD parameters at the femur or forearm improves risk assessment for osteoporotic fractures. We observe that using the WHO criteria with the manufacturers' normative data results in very inconsistent diagnoses. Only 25% of subjects are consistently diagnosed by all of the eight BMD variables. Such inconsistency is reduced by using a common elderly normative population as in model 2, in which case 50% of the subjects are consistently diagnosed as osteoporotic by all of the eight diagnostic methods. Risk-based diagnostic criteria as in model 3 improve consistency substantially to 68%. Combining the results of BMD assessments at more than one region of interest (ROI) from a single scan significantly increases prediction of hip and/or spine fracture risk and elevates the relative risk with increasing number of low BMD subregions. We conclude that standardization of normative data, perhaps referenced to an older population, may be necessary when applying T scores as diagnostic criteria in patient management. A risk-based osteoporosis classification does not depend on the manufacturers' reference data and may be more consistent and efficient for patient diagnosis.
Functional Impact of Human Collagen α2(XI) Gene Polymorphism in Pathogenesis of Ossification of the Posterior Longitudinal Ligament of the Spine
Authors: Maeda Shingo , Ishidou Yasuhiro , Koga Hiroaki , Taketomi Eiji , Ikari Katsunori , Komiya Setsuro , Takeda Jun , Sakou Takashi , Inoue Ituro 
Published: April 2006

Abstract
Ossification of the posterior longitudinal ligament (OPLL) of the spine is the leading cause of myelopathy in Japan. In earlier studies, we provided genetic linkage and allelic association evidence of distinct differences in the human collagen α2(XI) gene (COL11A2) that might constitute inherited predisposition to OPLL.(1) In the present study, a strong allelic association with non-OPLL (p = 0.0003) was observed with an intron 6 polymorphism [intron 6 (−4A)], in which the intron 6 (−4A) allele is more frequently observed in non-OPLL subjects than in OPLL patients. In addition, a newly identified polymorphism in exon 6 [exon 6 (+28A)] was in linkage disequilibrium with the intron 6 (−4A). The functional impact of the polymorphisms was analyzed by comparing the differences in messenger RNA (mRNA) splicing by reverse-transcription polymerase chain reaction (RT-PCR) analysis in cultured cells from the interspinous ligament and an in vitro exon trapping study. The intron 6 (−4A) allele resulted in skipping exon 6 and retaining exon 7, while the exon 6 (+28A) allele was not associated with alteration in mRNA splicing. Similar mRNA species were observed in undifferentiated osteoblast (Ob) cells and in cells from posterior longitudinal ligament of non-OPLL subjects. The region containing exons 6-8 is an acidic subdomain presumably exposed to the surface that could interact with molecules of the extracellular matrix. Accordingly, retaining exon 7 together with removal of exon 6 observed in intron 6 (−4A) could play a protective role in the ectopic ossification process because the same pattern was observed in undifferentiated Ob cells and nonossified posterior longitudinal ligament cells.