bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mutational Analysis and Functional Correlation With Phenotype in German Patients With Childhood-Type Hypophosphatasia
Authors: Orimo Hideo , Girschick Hermann J. , Goseki-Sone Masae , Ito Masahiro , Oda Kimimitsu , Shimada Takashi 
Published: April 2006

Abstract
The tissue-nonspecific alkaline phosphatase (TNSALP) gene from five German family members with childhood-type hypophosphatasia (HOPS) was analyzed using the polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP)-direct sequencing method. Four novel missense mutations (T51M, R54S, L258P, and R374H) and two that had been described previously (A160T and R206W) were detected in the respective patients. Mutation A160T was detected in 3 distinct patients, and a polymorphism V505A that had been described previously was detected in the same allele as L258P mutation in 1 patient and in 2 fathers whose V505A alleles were not transmitted to the probands. No other mutations were found in 2 patients. Transient expression of the mutant proteins in COS-1 cells showed that the four novel mutations and R206W were severe alleles, whereas A160T was a moderate allele. Analysis of its enzymatic activity and genetic transmission patterns confirmed that V505A was a polymorphism. Immunoprecipitation of the transiently expressed proteins showed that levels of the 80-kDa mature form of the enzyme were diminished or absent with the severe alleles; instead, levels of high-molecular mass disulfide-linked aggregates were increased. These results suggest that in compound heterozygotes, the combination of severe and moderate alleles may combine to cause the mild phenotype seen in childhood-type HOPS.
The Release and Activation of Transforming Growth Factor β2 Associated with Apoptosis of Chick Hypertrophic Chondrocytes
Authors: Gibson G. , Lin D.-L. , Wang X. , Zhang L. 
Published: April 2006

Abstract
The apoptosis of hypertrophic chondrocytes at the interface between growth cartilage and invading vessels is at the center of a series of critical events in endochondral formation. We have shown that the hypertrophy and apoptosis of chick chondrocytes in culture is associated with the release and activation of transforming growth factor β2 (TGF-β2). Supplementation of the culture medium with agents that influenced the maintenance of hypertrophic differentiation also influenced the release of TGF-β2. A large proportion of the TGF-β2 released from the cells was shown to be in an active form—particularly TGF-β2 associated with the support matrix. Inhibition of apoptosis with a broad-spectrum caspase inhibitor inhibited activation of the matrix-associated TGF-β2. However, inhibition of apoptosis did not diminish the release of TGF-β2. Release of TGF-β2 by chondrocytes at a late stage of their terminal differentiation and its activation in association with apoptosis may provide a mechanism controlling the processes of vascular invasion of growth cartilage and the deposition of bone matrix on nearby cartilage remnants.
Goats as an Osteopenic Animal Model
Authors: Leung K. S. , Siu W. S. , Cheung N. M. , Lui P. Y. , Chow D. H. K. , James A. , Qin L. 
Published: April 2006

Abstract
A large osteopenic animal model that resembles human osteoporotic changes is essential for osteoporosis research. This study aimed at establishing a large osteopenic animal model in goats. Twenty-five Chinese mountain goats were used in which they were either ovariectomized (OVX) and fed with a low-calcium diet (n = 16) or sham-operated (SHAM; n = 9). Monthly photodensitometric analysis on proximal tibial metaphysis and calcaneus was performed. Two iliac crest biopsy specimens obtained before and 6 months after OVX were used for bone mineral density (BMD) measurement with peripheral quantitative computed tomography (pQCT). Lumbar vertebrae (L2 and L7), humeral heads, and calcanei were collected for BMD measurement after euthanasia. The humeral heads and calcanei were used in biomechanical indentation test. BMD measurement showed a significant 25.0% (p = 0.006) decrease in BMD of the iliac crest biopsy specimens 6 months after OVX. It also was statistically significant when compared with the SHAM (p = 0.028). BMD at L2, L7, calcaneus, and humeral head reduced by 24–33% (p ranged from 0.001 to 0.011) when compared with the SHAM. Photodensitometry showed a continuous decrease in bone density after OVX. There were significant decreases of 18.9% in proximal tibial metaphysis (p = 0.003) and 21.8% in calcaneus (p = 0.023) in the OVX group 6 months postoperatively. Indentation test on the humeral head and calcaneus showed a significant decrease 52% (p = 0.006) and 54% (p = 0.001), respectively, in energy required for displacement of 3 mm in the OVX group compared with the SHAM group. The decreases correlated significantly to the decrease in BMD of the corresponding specimens (r2 = 0.439 and 0.581; p &lt; 0.001 for both). In conclusion, this study showed that OVX plus a low-calcium diet could induce significant osteopenia and deterioration of mechanical properties of the cancellous bone in goats.
Apparent Cure of a Newborn with Malignant Osteopetrosis Using Prednisone Therapy
Authors: Iacobini Metello , Migliaccio Silvia , Roggini Mario , Taranta Anna , Werner Beate , Panero Alessandra , Teti Anna 
Published: April 2006

Abstract
A newborn girl with hemorrhagic purpura, suspected neonatal sepsis, and pale and dry skin was lethargic with remarkable hepatosplenomegaly, convergent strabismus, severe anemia, and elevated alkaline phosphatase activity. Radiographs showed a generalized increase in bone density, small medullary cavities, sclerosis of the skull and vertebrae, transverse wavy stripes of sclerotic bone in the metaphyses, and bone-in-bone appearance in phalanges of hands and feet. On this basis, she was diagnosed with malignant infantile osteopetrosis. On the first day of life, the infant was given a blood transfusion and vitamin K (1 mg intravenously [iv]). Corticosteroid therapy was started with prednisone (2 mg/kg per day). She showed marked improvement of symptoms. On the 26th day and 42nd day of life, she received additional blood transfusions. On the 49th day, the patient was discharged and corticosteroid therapy was continued at a regimen of 5 mg/day. Subsequent blood sample analyses revealed normal values for age. At 1 year of life, a bone marrow sample showed normal white and red cell lineages. X-ray confirmed attenuation of the bone sclerosis; therefore, bone marrow transplantation (BMT) was not implemented. At the age of 1.5 years, prednisone therapy was discontinued gradually and withdrawn before the age of 2 years. Subsequent follow-up showed normalization of all radiological and hematologic parameters. At present, the patient is 3 years old and appears healthy with apparently complete regression of the disease.
Good Maintenance of Exercise-Induced Bone Gain with Decreased Training of Female Tennis and Squash Players: A Prospective 5-Year Follow-Up Study of Young and Old Starters and Controls
Authors: Kontulainen Saija , Kannus Pekka , Haapasalo Heidi , Sievänen Harri , Pasanen Matti , Heinonen Ari , Oja Pekka , Vuori Ilkka 
Published: April 2006

Abstract
This prospective 5-year follow-up study of 64 adult female racquet sports players and 27 controls assessed the changes in the playing-to-nonplaying arm bone mineral content (BMC) differences to answer three questions: (1) Are training-induced bone gains lost with decreased training? (2) Is the bone response to decreased training different if the playing career has been started before or at puberty rather than after it? (3) Are the possible bone changes related to the changes in training? The players were divided into two groups according to the starting age of their tennis or squash playing. The mean starting age was 10.5 years (SD, 2.2) among the players who had started training before or at menarche (young starters; n = 36) while 26.4 years (SD, 8.0) among those players who had begun training a minimum of 1 year after menarche (old starters; n = 28). At baseline of the 5-year follow-up, the mean age of the young starters was 21.6 years (SD, 7.6) and that of old starters was 39.4 years (SD, 10.5). During the follow-up, the young starters had reduced the average training frequency from 4.7 times a week (2.7) to 1.4 times a week (1.3) and the old starters from 4.0 times a week (1.4) to 2.0 times a week (1.4), respectively. The 5-year follow-up revealed that despite reduced training the exercise-induced bone gain was well maintained in both groups of players regardless of their clearly different starting age of activity and different amount of exercise-induced bone gain. The gain was still 1.3–2.2 times greater in favor of the young starters (at the follow-up, the dominant-to-nondominant arm BMC difference was 22% [8.4] in the humeral shaft of the young starters versus 10% [3.8] in the old starters, and 3.5% [2.4] in controls). In the players, changes in training were only weakly related to changes in the side-to-side BMC difference (rs = 0.05–0.34, all NS), and this was true even among the players who had stopped training completely a minimum 1 year before the follow-up. In conclusion, if controlled interventions will confirm our findings that an exercise-induced bone gain can be well maintained with decreased activity and that the maintenance of the bone gain is independent of the starting age of activity, exercise can be recommended for preventing osteoporosis and related fractures.
The Dose-Response Effects of Ethanol on the Human Fetal Osteoblastic Cell Line
Authors: Maran A. , Zhang M. , Spelsberg T. C. , Turner R. T. 
Published: April 2006

Abstract
Alcohol is a risk factor for the development of osteoporosis, especially in men. Chronic alcohol abuse decreases bone mass, which contributes to the increased incidence of fractures. To better understand the mechanism of action of ethanol on bone metabolism, we have studied the dose-response effects of ethanol on conditionally immortalized human fetal osteoblasts (hFOB) in culture. Ethanol treatment had no significant effects on osteoblast number after 1 day or 7 days. Ethanol treatment did not reduce type I collagen protein levels at either time point at any dose but slightly reduced alkaline phosphatase activity after 7 days. The messenger RNA (mRNA) levels for alkaline phosphatase, type I collagen, and osteonectin were unaltered by 24 h of ethanol treatment but a high dose (200 mM) reduced mRNA levels for the two bone matrix proteins after 7 days. Ethanol treatment led to dose-dependent increases in transforming growth factor β1 (TGF-β1) mRNA levels and decreases in TGF-β2 mRNA levels. The concentration of ethanol in the medium decreased with time because of evaporation but there was little degradation caused by metabolism. These results, which show that cultured osteoblasts are less sensitive than osteoblasts in vivo, suggest that the pronounced inhibitory effects of ethanol on bone formation are not caused by direct cell toxicity.
Bone Mineralization and Osteoblast Differentiation Are Negatively Modulated by Integrin αvβ3
Authors: Cheng Su-Li , Lai Chung-Fang , Blystone Scott D. , Avioli Louis V. 
Published: April 2006

Abstract
Numerous bone matrix proteins can interact with αv-containing integrins including αvβ3. To elucidate the net effects of the interaction between these proteins and αvβ3 on osteoblast function, we developed a murine osteoblastic cell line that overexpressed human αvβ3. Human αvβ3-integrin was expressed on cell membrane, in which its presence did not alter the surface level of endogenous mouse αvβ3. The expressed human αvβ3 was functional because cell adhesion to osteopontin was increased and this increment was abolished by antibody against human αvβ3. The proliferation rate of cells overexpressing αvβ3 (αvβ3-cells) was increased whereas matrix mineralization was decreased. To elucidate the mechanisms leading to inhibition of matrix mineralization, the expression of proteins important for mineralization was analyzed. Alkaline phosphatase activity and the expression of osteocalcin, type I collagen, and bone sialoprotein (BSP) were decreased whereas osteopontin was stimulated in αvβ3-cells. The regulation of osteopontin, osteocalcin, and BSP expression was mediated via transcriptional mechanism because their promoter activities were altered. Examination of molecules involved in integrin signaling indicated that activator protein-1 (AP-1) and extracellular signal-regulated kinase (Erk) activities were enhanced whereas c-jun N-terminal kinase (JNK) activity was decreased in αvβ3-cells. The activity of p38 and the levels of focal adhesion kinase (FAK) and vinculin were not altered. Moreover, the adhesions of αvβ3-cells to type I collagen and fibronectin were inhibited, which was attributed to decreased β1-integrin levels on cell surface. In conclusion, overexpressing αvβ3-integrin in osteoblasts stimulated cell proliferation but retarded differentiation, which were derived via altered integrin-matrix interactions, signal transduction, and matrix protein expression.
Strontium Ranelate Increases Cartilage Matrix Formation
Authors: Henrotin Y. , Labasse A. , Zheng S. X. , Galais Ph. , Tsouderos Y. , Crielaard J. M. , Reginster J. Y. 
Published: April 2006

Abstract
Based on previous studies showing that strontium ranelate (S12911) modulates bone loss in osteoporosis, it could be hypothesized that this drug also is effective on cartilage degradation in osteoarthritis (OA). This was investigated in vitro on normal and OA human chondrocytes treated or not treated with interleukin-1β (IL-1β). This model mimics, in vitro, the imbalance between chondroformation and chondroresorption processes observed in vivo in OA cartilage. Chondrocytes were isolated from cartilage by enzymatic digestion and cultured for 24–72 h with 10−4−10−3 M strontium ranelate, 10−3 M calcium ranelate, or 2 · 10−3 M SrCl2 with or without IL-1β or insulin-like growth factor I (IGF-I). Stromelysin activity and stromelysin quantitation were assayed by spectrofluorometry and enzyme amplified sensitivity immunoassay (EASIA), respectively. Proteoglycans (PG) were quantified using a radioimmunoassay. Newly synthesized glycosaminoglycans (GAGs) were quantified by labeled sulfate (Na235SO4) incorporation. This method allowed the PG size after exclusion chromatography to be determined. Strontium ranelate, calcium ranelate, and SrCl2 did not modify stromelysin synthesis even in the presence of IL-1β. Calcium ranelate induced stromelysin activation whereas strontium compounds were ineffective. Strontium ranelate and SrCl2 both strongly stimulated PG production suggesting an ionic effect of strontium independent of the organic moiety. Moreover, 10−3 M strontium ranelate increased the stimulatory effect of IGF-I (10−9 M) on PG synthesis but did not reverse the inhibitory effect of IL-1β. Strontium ranelate strongly stimulates human cartilage matrix formation in vitro by a direct ionic effect without stimulating the chondroresorption processes. This finding provides a preclinical basis for in vivo testing of strontium ranelate in OA.
The Effect of a Single Dose of Osteoprotegerin in Postmenopausal Women
Authors: Bekker Pirow J. , Holloway Donna , Nakanishi Arline , Arrighi Michael , Leese Philip T. , Dunstan Colin R. 
Published: April 2006

Abstract
Osteoprotegerin (OPG), a tumor necrosis factor (TNF) receptor family member, is a critical regulator of bone resorption. It is an important inhibitor of the terminal differentiation and activation of osteoclasts. This randomized, double-blind, placebo-controlled, sequential dose escalation study was conducted in postmenopausal women to determine the effect of a single subcutaneous (sc) dose of OPG on bone resorption as indicated by the biochemical markers, urinary N-telopeptide (NTX) and deoxypyridinoline (DPD), which are stable collagen degradation products. NTX levels decreased within 12 h after OPG administration. At the highest dose administered (3.0 mg/kg), a mean percent decrease in NTX of approximately 80% was observed 4 days after dosing. Six weeks after dosing a mean decrease of 14% in NTX was observed. The levels of bone-specific alkaline phosphatase (BSAP), a marker of bone formation, did not change for approximately 3 weeks after dosing. Thereafter, a modest decrease, reaching approximately 30% at 6 weeks, was observed in the 3.0-mg/kg dose group. The rapid decrease from baseline in NTX and delayed decrease in BSAP indicated that OPG acted primarily on osteoclasts to decrease bone resorption. OPG injections are well tolerated. This study, for the first time, indicates that a single sc injection of OPG is effective in rapidly and profoundly reducing bone turnover for a sustained period and that OPG therefore may be effective in treatment of bone diseases characterized by increased bone resorption such as osteoporosis.
Interaction Between the Vitamin D Receptor Gene and Collagen Type Iα1 Gene in Susceptibility for Fracture
Authors: Uitterlinden André G. , Weel Angelique E. A. M. , Burger Huib , Fang Yue , Van Duijn Cornelia M. , Hofman Albert , Van Leeuwen Johannes P. T. M , Pols Huibert A. P. 
Published: April 2006

Abstract
Osteoporosis is a common disease with a strong genetic component. Polymorphisms in the vitamin D receptor (VDR) gene have been implicated in osteoporosis but explain only a small part of the genetic effect on bone mineral density (BMD) while their effect on fractures is still uncertain. Recently, a G to T polymorphism in an Sp1 site in the collagen type Iα1 (COLIA1) gene was found to be associated with reduced BMD and with increased fracture risk. To analyze the combined influence of polymorphisms in the VDR gene and the COLIA1 gene in determining the susceptibility to osteoporotic fracture, we studied 1004 postmenopausal women. The “baT ” VDR haplotype, constructed from three adjacent restriction fragment length polymorphisms, was found to be overrepresented among fracture cases (p = 0.009). This corresponded to an odds ratio (OR) of 1.8 (95% CI, 1.0–3.3) for heterozygous carriers and 2.6 (95%CI, 1.4–5.0) for homozygous carriers of the risk haplotype. The effect was similar for vertebral and nonvertebral fractures and, most importantly, independent of BMD. We observed significant interaction (p = 0.03) between VDR and COLIA1 genotype effects. Fracture risk was not VDR genotype-dependent in the COLIA1 “reference” group (genotype GG) while in the COLIA1 “risk” group (genotypes GT and TT) the risk of fracture was 2.1 (95%CI, 1.0–4.4) for heterozygous and 4.4 (95%CI, 2.0–9.4) for homozygous carriers of the VDR risk haplotype. We conclude that both the VDR and the COLIA1 polymorphisms are genetic markers for osteoporotic fracture in women, independent of BMD. Our data indicate that interlocus interaction is likely to be an important component of osteoporotic fracture risk.
Postnatal and Pubertal Skeletal Changes Contribute Predominantly to the Differences in Peak Bone Density Between C3H/HeJ and C57BL/6J Mice
Authors: Richman C. , Kutilek S. , Miyakoshi N. , Srivastava A. K. , Beamer W. G. , Donahue L. R. , Rosen C. J. , Wergedal J. E. , Baylink D. J. , Mohan S. 
Published: April 2006

Abstract
Previous studies have shown that 60–70% of variance in peak bone density is determined genetically. The higher the peak bone density, the less likely an individual is to eventually develop osteoporosis. Therefore, the amount of bone accrued during postnatal and pubertal growth is an important determining factor in the development of osteoporosis. We evaluated the contribution of skeletal changes before, during, and after puberty to the development of peak bone density in C3H/HeJ (C3H) and C57BL/6J (B6) mice. Volumetric bone density and geometric parameters at the middiaphysis of femora were measured by peripheral quantitative computed tomography (pQCT) from days 7 to 56. Additionally, biochemical markers of bone remodeling in serum and bone extracts were quantified. Both B6 and C3H mice showed similar body and femoral weights. B6 mice had greater middiaphyseal total bone area and thinner cortices than did C3H mice. Within strains, males had thicker cortices than did females. C3H mice accumulated more minerals throughout the study, with the most rapid accumulation occurring postnatally (days 7–23) and during pubertal maturation (days 23–31). C3H mice had higher volumetric bone density as early as day 7, compared with B6 mice. Higher serum insulin-like growth factor I (IGF-I) was present in C3H mice postnatally at day 7 and day 14. Until day 31, B6 male and female mice had significantly higher serum osteocalcin than C3H male and female mice, respectively. Alkaline phosphatase (ALP) was found to be significantly higher in the bone extract of C3H mice compared with B6 mice at day 14. These data are consistent with and support the hypothesis that the greater amount of bone accrued during postnatal and pubertal growth in C3H mice compared with B6 mice may be caused by increased cortical thickness, increased endosteal bone formation, and decreased endosteal bone resorption.
Inaccuracies Inherent in Patient-Specific Dual-Energy X-Ray Absorptiometry Bone Mineral Density Measurements: Comprehensive Phantom-Based Evaluation
Authors: Bolotin H. H. , Sievänen H. , Grashuis J. L. , Kuiper J. W. , Järvinen T. L. N. 
Published: April 2006

Abstract
An extensive series of dual-energy X-ray absorptiometry (DXA) scans and dual polyenergetic X-ray simulation studies of 150 different phantom arrays were carried out to evaluate quantitatively the extent of systematic inaccuracies inherent in DXA in vivo bone mineral density (BMD). These measurements are particularly relevant to lumbar vertebral and proximal femoral sites. The phantoms were specially fabricated near perfect absorptiometric representations of bone material, red marrow (RM) and yellow marrow (YM), and extraosseous mixtures of fat (F) and lean muscle that spanned the full range of soft tissue anthropometrics encountered clinically. In each case, the DXA-measured BMD values obtained using Hologic, Lunar, and Norland densitometers were found to be virtually the same and to be in excellent agreement with the corresponding quantitative simulation study BMD results. Comparisons of the known phantom BMD values and DXA-measured BMD in each case allowed the BMD inaccuracies to be evaluated. These present findings show that these ubiquitous inaccuracies in DXA BMD methodology are of in vivo soft tissue anthropometric genesis. It is found that patient-specific DXA-measured in vivo BMD inaccuracies as high as 20% or more can be readily anticipated clinically, particularly in cases of osteopenic, osteoporotic, and elderly patients. As these inaccuracies exceed considerably DXA precision errors, they may compromise patient-specific evaluations of fracture risk and, in prospective studies, mask or exaggerate clinically significant true changes in BMD. It is concluded that the magnitudes and variability of inherent inaccuracies in DXA-measured in vivo BMD underscore the need for prudence and circumspection in interpretations and assessments of DXA-based clinical studies.