bluuebunny/crossref_metadata_2025_split huggingface dataset:
Heterogeneity in the Growth of the Axial and Appendicular Skeleton in Boys: Implications for the Pathogenesis of Bone Fragility in Men
Authors: Bradney Michelle , Karlsson Magnus K. , Duan Yunbo , Stuckey Stephen , Bass Shona , Seeman Ego 
Published: April 2006

Abstract
Men with spine fractures have reduced vertebral body (VB) volume and volumetric bone mineral density (vBMD). Men with hip fractures have reduced femoral neck (FN) volume and vBMD, site-specific deficits that may have their origins in growth. To describe the tempo of growth in regional bone size, bone mineral content (BMC), and vBMD, we measured bone length, periosteal and endocortical diameters, BMC, and vBMD using dual-energy X-ray absorptiometry in 184 boys aged between 7 and 17 years. Before puberty, growth was more rapid in the legs than in the trunk. During puberty, leg growth slowed while trunk length accelerated. Bone size was more advanced than BMC in all regions, being ∼70% and ∼35% of their predicted peaks at 7 years of age, respectively. At 16 years of age, bone size had reached its adult peak while BMC was still 10% below its predicted peak. The legs accounted for 48%, whereas the spine accounted for 10%, of the 1878 g BMC accrued between 7 and 17 years. Peripubertal growth contributed (i) 55% of the increase in leg length but 78% of the mineral accrued and (ii) 69% of the increase in spine length but 87% of the mineral accrued. Increased metacarpal and midfemoral cortical thickness was caused by respective periosteal expansion with minimal change in the endocortical diameter. Total femur and VB vBMD increased by 30–40% while size and BMC increased by 200–300%. Thus, growth builds a bigger but only slightly denser skeleton. We speculate that effect of disease or a risk factor during growth depends on the regions maturational stage at the time of exposure. The earlier growth of a regions size than mass, and the differing growth patterns from region to region, predispose to site-specific deficits in bone size, vBMD, or both. Regions further from their peak may be more severely affected by illness than those nearer completion of growth. Bone fragility in old age is likely to have its foundations partly established during growth.
Functional Characterization of Osteoblasts and Osteoclasts from Alkaline Phosphatase Knockout Mice
Authors: Wennberg Charlotte , Hessle Lovisa , Lundberg Pernilla , Mauro Sonia , Narisawa Sonoko , Lerner Ulf H. , Millán José Luis 
Published: April 2006

Abstract
Tissue nonspecific alkaline phosphatase (TNAP) knockout (ko) mice manifest defects in bone mineralization that mimic the phenotypic abnormalities of infantile hypophosphatasia. In this article, we have searched for phenotypic differences between calvarial osteoblasts and osteoclasts in wild-type (wt), heterozygous and homozygous TNAP null mice. In vitro release of45Ca from calvarial bones, with and without stimulation with parathyroid hormone (PTH), revealed no functional difference between osteoclasts from the three TNAP genotypes. Studies of primary cultures of TNAP+/+, TNAP+/−, and TNAP−/− calvarial osteoblasts revealed no differences in the rate of protein synthesis or in the expression levels of messenger RNAs (mRNAs) for osteopontin (OP), osteocalcin (OC), collagen type I, core binding factor α1 (Cbfa 1), N-cadherin, Smad 5, and Smad 7. Release of interleukin-6 (IL-6) from calvarial osteoblasts under basal conditions and after stimulation with PTH, tumor necrosis factor α (TNF-α) or IL-1β was similar in all genotypes. The amount of cyclic adenosine monophosphate (cAMP) accumulation also was comparable. However, although cultures of primary TNAP−/− osteoblasts were able to form cellular nodules as well as TNAP positive osteoblasts do, they lacked the ability to mineralize these nodules in vitro. Mineralization also was delayed in TNAP+/− osteoblast cultures compared with cultures of wt osteoblasts. Incubation with media supplemented with recombinant TNAP, but not with enzymatically inactive TNAP, restored mineralization in ko osteoblast cultures. Our data provide evidence that osteoblasts in TNAP null mice differentiate normally but are unable to initiate mineralization in vitro. The fact that even heterozygous osteoblasts show delayed mineralization provides a rationale for the presence of bone disease in carriers of hypophosphatasia.
Further Evidence for Genetic Heterogeneity Within Type II Autosomal Dominant Osteopetrosis
Authors: Bénichou O. D. , Bénichou B. , Copin H. , De Vernejoul M. C. , Van Hul W. 
Published: April 2006

Abstract
Type II autosomal dominant osteopetrosis (ADO II) is characterized by an increased bone mass that contrasts with the high frequency of fractures. Linkage analysis performed in an extensive Danish family recently provided evidence for the mapping of an ADO II gene to an 8.5-cM region in chromosome 1p21 between microsatellite markers D1S486 and D1S2792. We recruited, phenotyped, and haplotyped 4F catheter ADO II families including 18 affected subjects and 29 unaffected subjects in order to narrow the candidate region and to search for genetic heterogeneity. ADO II diagnosis was ascertained by the observation of vertebral end plate thickening in at least 2 patients from successive generations. Linkage studies involved five microsatellite markers (D1S486, D1S206, D1S495, D1S248, and D1S2792) spanning 1p21. Haplotype analyses of two of our families clearly excluded the tested locus. The two remaining families gave poorly informative results. These results, combined with those previously reported in two American families, suggest that chromosomal region 1p21 is most likely a minor locus for ADO II.
Mineral Density and Bone Strength Are Dissociated in Long Bones of Rat Osteopetrotic Mutations
Authors: Tuukkanen J. , Koivukangas A. , Jämsä T. , Sundquist K. , MacKay C. A. , Marks S. C. 
Published: April 2006

Abstract
Bone mineral density (BMD) and mechanical strength generally show strong positive correlations. However, osteopetrosis is a metabolic bone disease with increased skeletal density radiographically and increased risk of fracture. We have evaluated mechanical strength and mineral density in three osteopetrotic mutations in the rat (incisors-absent [ia/ia], osteopetrosis [op/op], and toothless [tl/tl]) to test the hypothesis that reduced bone resorption in one or more of these mutations results in weaker bones in the presence of greater mineral density and skeletal mass. Peripheral quantitative computed tomography (pQCT) was used to analyze BMD and cross-sectional geometry in the tibial diaphysis and metaphysis as well as the femoral diaphysis and femoral neck. The bending breaking force of tibial and femoral midshafts was obtained using the three-point bending test and femoral neck strength was tested by axial loading. Osteopetrotic mutants were significantly smaller than their normal littermates (NLMs) in each stock. The pQCT analysis showed that BMD and bone mineral content (BMC) were higher than or equal to NLMs in all skeletal sites measured in the osteopetrotic mutants. However, the mechanical breaking force was equal to or lower than their NLMs in all sites. The cross-sectional structure of long bone shafts was markedly different in osteopetrotic mutants, having a thin cortex and a medullary area filled with primary trabecular bone. These results indicate that osteopetrotic mutations in the rat increase bone density and decrease bone strength. The tibial diaphysis was significantly weaker in tl/tl and ia/ia mutants and the tibial metaphysis showed the greatest increase in BMD in all mutants. These data are another illustration that an increased BMD does not necessarily lead to stronger bones.
Intercellular Adhesion Molecule 1 Discriminates Functionally Different Populations of Human Osteoblasts: Characteristic Involvement of Cell Cycle Regulators
Authors: Tanaka Yoshiya , Maruo Akihiko , Fujii Koichi , Nomi Masashi , Nakamura Toshitaka , Eto Sumiya , Minami Yasuhiro 
Published: April 2006

Abstract
The concept of differential regulation of certain adhesion molecules on different cell subsets and their relevance to cell functions has emerged in recent years. The initial event in bone remodeling is an increase in osteoclastic bone resorption and cell adhesion between osteoclastic precursors and bone marrow stromal cells or osteoblasts is known to commit the osteoclast development. Here, we show that human osteoblasts can be divided into two subsets based on the expression of the intercellular adhesion molecule (ICAM)-1; ICAM-1+ osteoblasts highly adhered to monocytes, including osteoclast precursors, produced osteoclast differentiation factor (ODF), and induced multinuclear osteoclast-like cell formation. Anti-ODF monoclonal antibody (mAb) did not inhibit the adhesion of monocytes to osteoblastic cells, whereas anti-leukocyte function-associated antigen (LFA)-1, a receptor for ICAM-1, mAb blocked the adhesion. We thereby propose that the higher affinity adhesion via LFA-1/ICAM-1 is prerequisite for efficient function of membrane-bound ODF during osteoclast maturation. The functional characteristics of ICAM-1+ osteoblasts were emphasized further by cell cycle regulation, as manifested by (i) up-regulation of p53 and p21, (ii) reduction of activity of cyclin-dependent kinase (cdk) 6, (iii) underphosphorylation of retinoblastoma protein, (iv) increased Fas but reduced bcl-2 expression, and (v) majority of cells remained at G0/G1 phase. Furthermore, ICAM-1+ osteoblasts were induced by interleukin-1β (IL-1β). Taken together, we propose that the differentiation of osteoblasts to ICAM-1+ subpopulation by inflammatory cytokines plays an important role in osteoporosis, which is observed in patients with chronic inflammation, because ICAM-1+ osteoblasts can bias bone turnover to bone resorption, committing osteoclast maturation through cell adhesion with its precursor, and the majority of ICAM-1+ osteoblasts arrested at G0/G1 phase. Such regulation of cell cycle arrest also is an important determinant of the life span of cells in bone in which continuous bone remodeling maintains its homeostasis.
Association of the Vitamin D Receptor Genotype BB with Low Bone Density in Hyperthyroidism
Authors: Obermayer-Pietsch Barbara M. , Frühauf Gerwig E. , Chararas Kornelia , Mikhail-Reinisch Sabine , Renner Wilfried , Berghold Andrea , Kenner Lukas , Lackner Carolin 
Published: April 2006

Abstract
Bone mineral density (BMD) is modulated by genetic and environmental factors or certain diseases. In several conditions such as low calcium intake, an influence of vitamin D receptor (VDR) polymorphisms on BMD has been suggested. In the present study, we investigated the relationship of Bsm I and Fok I polymorphisms of the VDR gene and BMD in patients with hyperthyroidism, a disease that often results in low BMD. Bsm I and Fok I genotypes were determined in 76 postmenopausal hyperthyroid patients and 62 healthy postmenopausal women as controls. Patients and controls were matched for age, time since menopause, and lifestyle factors and were free of estrogen medication. BMD evaluation included axial dual X-ray absorptiometry (DXA) and peripheral quantitative computed tomography (PQCT). Low BMD was defined as −2.5 STD below the young adult mean value. Biochemical parameters investigated were thyroid hormones, osteocalcin, and 25-(OH)-vitamin D3 as well as routine laboratory data. Low BMD was found in 61% of hyperthyroid patients and in only 23% of euthyroid controls. In the group of hyperthyroid patients with low bone density, the BB genotype (VDR Bsm I polymorphisms) was significantly more frequent (39%) than in controls (13%; p = 0.003) and hyperthyroid patients with normal BMD (6%; p = 0.013). The odds ratio (OR) for low BMD in patients with BB genotype was 5.7 (95% CI, 1.7-19.1; p &lt; 0.005) as compared with the Bb and bb genotypes and 5.5 (95% CI, 2.3-13.2; p &lt; 0.0001) for hyperthyroidism alone. The cumulative risk for low BMD in patients with hyperthyroidism and BB genotype was 31.4 (95% CI, 3.9-256; p &lt; 0.0003). VDR Fok I genotypes showed no significant relationship with BMD or other general or bone-specific parameters. Thus, hyperthyroidism and the genetic background of a BB genotype may promote synergistically the development of low BMD in hyperthyroid patients. Screening for the BB genotype in these patients therefore could help to identify those with particularly high risk for the development of low BMD and allow early treatment.
Characterization of Perimenopausal Bone Loss: A Prospective Study
Authors: Recker R. , Lappe J. , Davies K. , Heaney R. 
Published: April 2006

Abstract
This study characterized the change in bone mass, bone markers, pituitary/gonadal hormones, vitamin D, parathyroid hormone, and anthropometric variables in a cohort of healthy women as they passed through normal menopause. We recruited 75 women &gt; 46 years old who had premenopausal estradiol (E2) and gonadotropin levels and regular menses. During 9.5 years of observation, 54 experienced normal menopause (PM group) and 21 remained estrogen replete (ER group). Before the beginning of the menopausal drop and after its completion, the slope of bone mass on time in the PM group was 0% for the spine, −0.61% per year for the total body, and −0.45% per year for the femoral neck. Designating these losses as “age related,” there were 0, 4.88, and 3.40% losses for spine, total body bone mineral (TBBM), and femoral neck, respectively, in the 8-year period for which the data were analyzed. Across menopause, we found a sigmoid pattern of bone loss in the PM group beginning about 2–3 years before the last menses and ending about 3–4 years after the last menses. The total estrogen-deprivation bone losses were 10.50, 7.73, and 5.30% for the spine, TBBM, and femoral neck, respectively. In the ER group, we found a 0, 0.59, and 0.93% per year loss in spine, TBBM, and femoral neck, respectively. Serum osteocalcin rose 77%, serum total alkaline phosphatase rose 34%, and urinary hydroxyproline/creatinine (Hypro/Cr) ratio rose 44% in the PM group, while remaining stable in the ER group. We conclude that menopausal bone loss is a composite of loss caused by estrogen deprivation and age per se for the hip and total body, but is caused by estrogen deprivation alone for the spine.
Rate of Bone Loss Is Associated with Mortality in Older Women: A Prospective Study
Authors: Kado Deborah M. , Browner Warren S. , Blackwell Terri , Gore Robert , Cummings Steven R. 
Published: April 2006

Abstract
Older women with low bone density have an increased risk of fracture, cardiovascular disease, and mortality. However, it is not known whether this association is caused by ongoing bone loss or by lower bone mass earlier in life. To determine whether rate of bone loss is associated with total and cause-specific mortality, we prospectively studied 6046 women aged 65 years or older who had serial bone mineral density (BMD) measurements as a part of the Study of Osteoporotic Fractures. Rates (mean ± SD) of loss of BMD at the heel (for a mean of 5.7 years) and hip (for a mean of 3.5 years) were estimated. Cause-specific mortality was ascertained from death certificates and hospital records. BMD loss at the heel was 5.9 ± 6.0 mg/cm2 per year (1.5 ± 1.5%) and BMD loss at the hip was 4.1 ± 10.2 mg/cm2 per year (0.6 ± 1.4%). During an average follow-up of 3.2 years after the second measurement of BMD, 371 deaths occurred. Each SD increase in BMD loss at the hip was associated with a 1.3-fold (95% CI, 1.1-1.4) increase in total mortality, adjusted for age, baseline BMD, diabetes, hypertension, incident fractures, smoking, physical activity, health status, weight loss, and calcium use. In particular, hip BMD loss was associated with increased mortality from coronary heart disease (relative hazard [RH] = 1.3 per SD; 95% CI, 1.0-1.8) and pulmonary diseases (RH = 1.6 per SD; 95% CI, 1.1-2.5). The findings were similar for bone loss at the heel, except there was no significant association with pulmonary mortality. These results raise the possibility that bone loss may share common etiologies with coronary and pulmonary diseases.
Contribution of Organic Material to the Ion Composition of Bone
Authors: Bushinsky David A. , Gavrilov Konstantin L. , Chabala Jan M. , Levi-Setti Riccardo 
Published: April 2006

Abstract
Studies of bone mineral ranging from cadaveric analysis to the use of high-resolution ion microprobe with secondary ion mass spectroscopy (SIMS) have concluded that bone is rich in sodium and potassium relative to calcium. Exposure of bone to acid conditions either in vitro or in vivo leads to an exchange of hydrogen ions for sodium and potassium buffering the acidity of the medium or blood, respectively. Whether these monovalent ions reside within the mineral or organic phases of bone has never been determined. To determine the contribution of organic material to bone ion composition, we dissected calvariae from 4- to 6-day-old mice, removed organic material of some with hydrazine (Hydr), and prepared all bones for analysis using a high-resolution scanning ion microprobe coupled to a secondary ion mass spectrometer. We found that in non-Hydr-treated calvariae (Ctl) there was far more surface sodium and potassium than calcium (23Na/40Ca = 15.7 + 1.9, ratio of counts of detected secondary ions, mean + 95% CI,39K/40Ca = 44.0 + 1.5). Removal of organic material with hydrazine (Hydr) led to a marked fall in the ratio of sodium to calcium and potassium to calcium (23Na/40Ca = 5.9 + 1.4, p &lt; 0.025 vs. respective Ctl and39K/40Ca = 1.1 + 1.5, p &lt; 0.001 vs. respective Ctl). Similarly, when examining the cross-section of the calvariae there was more sodium and potassium than calcium (23Na/40Ca = 8.6 + 1.6,39K/40Ca = 26.7 + 1.8). Treatment with Hydr again caused a marked fall in both ratios (23Na/40Ca = 0.3 + 1.6, p &lt; 0.001 vs. respective Ctl and39K/40Ca = 0.02 + 1.9, p &lt; 0.001 vs. respective Ctl). Thus, within bone the organic material contains the majority of the sodium and potassium. This suggests that the organic material in bone and not the mineral itself is responsible for the acute buffering of the additional hydrogen ions during metabolic acidosis.
Intravenous Pamidronate for Treatment of Reflex Sympathetic Dystrophy During Breast Feeding
Authors: Siminoski K. , Fitzgerald A. A. , Flesch G. , Gross M. S. 
Published: April 2006

Abstract
A 39-year-old woman presented in the first month of pregnancy with reflex sympathetic dystrophy involving both lower legs. Symptoms became so severe that she could not walk unassisted, and the pain worsened after delivery. Radiographs showed patchy reduction in apparent density in the tarsal bones and around the ankles and knees. Uptake was increased in these areas on technetium methylene diphosphonate bone scan. Bone density (dual-energy X-ray absorptiometry) was reduced in the spine, hip, and radius. Biochemical tests were normal except for an increase in urinary excretion of the N-telopeptide cross-linking region of type I collagen (NTx). Because the patient wanted to continue breast-feeding, intravenous pamidronate was administered at monthly intervals. Breast milk was collected for 48 h after the infusion. The pain began to decrease soon after drug administration was initiated, and it was virtually gone by 6 months. NTx excretion fell by 78% and bone density increased by as much as 18.9% over the 6-month treatment interval. The baby was healthy and grew normally. Milk expressed after the first treatment was assayed for pamidronate content by high-performance liquid chromatography with fluorescence detection. None was detected (limit of quantitation, 0.4 μmol/liter). This case shows that pamidronate may be considered for treatment of lactating women.
Progressive Osseous Heteroplasia
Authors: Kaplan Frederick S. , Shore Eileen M. 
Published: April 2006

Abstract
Progressive osseous heteroplasia (POH) is a recently described genetic disorder of mesenchymal differentiation characterized by dermal ossification during infancy and progressive heterotopic ossification of cutaneous, subcutaneous, and deep connective tissues during childhood. The disorder can be distinguished from fibrodysplasia ossificans progressiva (FOP) by the presence of cutaneous ossification, the absence of congenital malformations of the skeleton, the absence of inflammatory tumorlike swellings, the asymmetric mosaic distribution of lesions, the absence of predictable regional patterns of heterotopic ossification, and the predominance of intramembranous rather than endochondral ossification. POH can be distinguished from Albright hereditary osteodystrophy (AHO) by the progression of heterotopic ossification from skin and subcutaneous tissue into skeletal muscle, the presence of normal endocrine function, and the absence of a distinctive habitus associated with AHO. Although the genetic basis of POH is unknown, inactivating mutations of the GNAS1 gene are associated with AHO. The report in this issue of the JBMR of 2 patients with combined features of POH and AHO—one with classic AHO, severe POH-like features, and reduced levels of Gsα protein and one with mild AHO, severe POH-like features, reduced levels of Gsα protein, and a mutation in GNAS1—suggests that classic POH also could be caused by GNAS1 mutations. This possibility is further supported by the identification of a patient with atypical but severe platelike osteoma cutis (POC) and a mutation in GNAS1, indicating that inactivating mutations in GNAS1 may lead to severe progressive heterotopic ossification of skeletal muscle and deep connective tissue independently of AHO characteristics. These observations suggest that POH may lie at one end of a clinical spectrum of ossification disorders mediated by abnormalities in GNAS1 expression and impaired activation of adenylyl cyclase. Analysis of patients with classic POH (with no AHO features) is necessary to determine whether the molecular basis of POH is caused by inactivating mutations in the GNAS1 gene.
Parathyroid Hormone-Related Peptide Stimulates Proliferation of Highly Tumorigenic Human SV40-Immortalized Breast Epithelial Cells
Authors: Cataisson Christophe , Lieberherr Michele , Cros Magali , Gauville Christiane , Graulet Anne-Marie , Cotton Joel , Calvo Fabien , de Vernejoul Marie-Christine , Foley John , Bouizar Zhor 
Published: April 2006

Abstract
Parathyroid hormone-related protein (PTHrP) is the main mediator of humoral hypercalcemia of malignancy (HHM) and it is produced by many tumors, including breast cancers. Breast epithelial cells as well as breast cancer tumors and cell lines have been reported as expressing PTHrP and the PTH/PTHrP receptor, suggesting that PTHrP may act as an autocrine factor influencing proliferation or differentiation of these cell types. We investigated PTHrP gene expression, PTH/PTHrP receptor signaling, and PTHrP-induced mitogenesis in three immortalized human mammary epithelial cell lines that exhibit differential tumorigenicity. The most tumorigenic cells expressed the highest levels of PTHrP messenger RNA (mRNA) and protein. We used reverse-transcription polymerase chain reaction (RT-PCR) and immunoblotting to detect the PTH/PTHrP receptor transcripts and proteins in all of the three cell lines. Treatment with human PTHrP(1-34) [hPTHrP(1-34)] and hPTH(1-34) increased intracellular cyclic adenosine monophosphate (cAMP) but not free Ca2+ in the nontumorigenic line. These agonists increased both cAMP and free Ca2+ levels in the moderately tumorigenic line, but only increased free Ca2+ in the highly tumorigenic line. Application of the PTH/PTHrP receptor antagonist [Asn10,Leu11,D Trp12]PTHrP(7-34) or PTHrP antibodies reduced [3H]thymidine incorporation in a dose-dependent fashion in the highly tumorigenic cell line but did not affect the other lines. Thus, treatment with a PTH/PTHrP receptor antagonist reduced cell proliferation, suggesting that PTHrP signaling mediated by the phospholipase C (PLC) pathway stimulates proliferation of a highly tumorigenic immortalized breast epithelial cell line.