bluuebunny/crossref_metadata_2025_split huggingface dataset:
Expression of the Mutant (1735T-DEL) Tissue-Nonspecific Alkaline Phosphatase Gene from Hypophosphatasia Patients
Authors: Dr. Goseki-Sone Masae , Orimo Hideo , Iimura Tadahiro , Miyazaki Hidetaka , Oda Kimimitsu , Shibata Hisanobu , Yanagishita Masaki , Takagi Yuzo , Watanabe Hisashi , Shimada Takashi , Oida Shinichiro 
Published: April 2006

Abstract
Hypophosphatasia (HOPS) is an inherited disorder characterized by defects in skeletal mineralization due to the deficiency of tissue-nonspecific alkaline phosphatase (TNSALP). To date, various mutations in the TNSALP gene have been identified. Especially, a deletion of T at position 1735 (1735T-del) located in exon 12 has been detected in three genetically unrelated Japanese patients, which seems to be one of the hot spots among the causative mutations in Japanese HOPS patients. 1735T-del causes a frame shift downstream from codon 503 (Leu), and consequently the normal termination codon at 508 is eliminated. Since a new inframe termination codon appears at codon 588 in the mutant DNA, the resultant protein is expected to have 80 additional amino acids. Expression of the mutant TNSALP gene using COS-1 cells demonstrated that the protein translated from the mutant 1735T-del had undetectable ALP activity, and its molecule size was larger than normal, as expected. Interestingly, an immunoprecipitation study of patients' sera using antibody against TNSALP revealed an abnormal protein which corresponded in size to the mutated TNSALP expressed by COS-1 cells, suggesting that the abnormal TNSALP is made by HOPS patients. The detection of TNSALP in cells transfected with 1735T-del using an immunofluorescent method exhibited only a faint signal on the cell surface, but an intense intracellular fluorescence after permeabilization.
Expression of Src Family Kinases and Their Putative Substrates in the Human Preosteoclastic Cell Line FLG 29.1
Authors: Jeschke Margit , Brandi Maria-Luisa , Dr. Šuša Mira 
Published: April 2006

Abstract
Several lines of evidence suggest that the c-Src tyrosine kinase has a specific role in bone-resorbing osteoclasts. To investigate this further, we examined the expression of c-Src, its kinase family members, and their putative substrates in the human leukemia cell line FLG 29.1. Western blot analysis with specific antibodies against Src family members showed expression of Src, Fyn, and Lyn, lower levels of Yes and Hck, and the absence of Lck tyrosine kinase. During a 3-day treatment with phorbol 12-myristate, 13-acetate (PMA), which induces differentiation of FLG 29.1 cells toward an osteoclast-like phenotype, the levels of Src and Fyn increased and the levels of Lyn decreased. In a similar leukemia cell line, HL-60, Src protein was not constitutively expressed and not induced by PMA treatment, which leads to monocytic differentiation. PMA treatment of FLG 29.1 cells induced a strong increase in the expression of p120 Cbl and Pyk2 kinase, which are putative Src substrates. Pyk2 phosphorylation increased upon adherence of FLG 29.1 cells to fibronectin and to ST2 stromal cells. The expression of other Src substrates and interacting proteins, such as p120 Cas, p130 Cas, vinculin, Fak kinase, and the p85 phosphatidylinositol 3-kinase subunit either did not change or slightly increased during PMA treatment. The elevated total protein tyrosine phosphorylation in PMA-treated FLG 29.1 cells was abolished by herbimycin A, a Src inhibitor. These data are consistent with the proposed role of Src in the osteoclastic function and support the use of FLG 29.1 cells as a model to study Src substrates in the cells of the osteoclastic lineage.
Bone Density and Fracture Risk in Men
Authors: Dr. Melton L. Joseph , Atkinson Elizabeth J. , O'Connor Michael K. , O'Fallon W. Michael , Riggs B. Lawrence 
Published: April 2006

Abstract
We evaluated different definitions of osteoporosis in a population-based sample of 348 men (age 22–90 years) compared with 351 women (age 21–93 years). Thirty-six men (10%) and 46 women (13%) had a history of osteoporotic fracture (hip, spine, or distal forearm due to moderate trauma at ≥ age 35). In logistic regression analysis, osteoporotic fracture risk was associated with bone mineral density (BMD) at all sites (neck, trochanter, total hip, lumbar spine, and total wrist) in both genders (p &lt; 0.001) except spinal BMD in men. After adjusting for age, total hip BMD was the strongest predictor of fracture risk in women (odds ratio [OR] per 1 SD decline, 2.4; 95% confidence interval [CI], 1.6–3.7), while wrist BMD was best in men (OR, 1.5; 95% CI, 1.1–2.0). Among men but not women, bone mineral apparent density (BMAD) was a better predictor of fracture than BMD (wrist BMAD OR, 1.7; 95% CI, 1.3–2.3). Hip BMD/BMAD decreased linearly from age 20 years onward in both genders, while spinal BMD/BMAD declined after age 40 in women but not in men. In both genders, total wrist BMD/BMAD decreased after age 50. By World Health Organization criteria, the age-adjusted prevalence of osteoporosis at the hip, spine, or wrist was 35% among women ≥50 years of age. A similar approach (BMD &gt; 2.5 SD below the young male mean) produced an osteoporosis prevalence rate in men ≥50 years of age of 19%. Thus, bone density predicts fracture risk in men as it does in women, and the prevalence of osteoporosis in men, using sex-specific normal values, is substantial. These observations indicate a need for better prevention and treatment strategies for men.
Predictors for Falls and Fractures in the Longitudinal Aging Study Amsterdam
Authors: Tromp A. M. , Smit J. H. , Deeg D. J. H. , Bouter L. M. , Dr. Lips P. 
Published: April 2006

Abstract
The objective of this study was to identify easily measurable predictors for falls, recurrent falls, and fractures using a population-based prospective cohort study of 1469 elderly, born before 1931, in three regions of the Netherlands. The baseline at-home interview was in 1992. In 1995, falls experienced in the preceding year and fractures over the preceding 38-month period were registered. In a period of 1 year, 32% of the participants fell at least once, and 15% fell two or more times. The rate of recurrent falls was similar in men and women up until the age of 75 years. The total number of fractures was 85, including 23 wrist fractures, 12 hip fractures, and 9 humerus fractures. The incidence density per 1000 person-years for any fracture was 25.1 (95% confidence interval [CI], 18.9–31.4) for women and 8.2 (95% CI, 4.5–12.0) for men, respectively. Multiple logistic regression identified urinary incontinence, impaired mobility, use of analgetics, and use of antiepileptic drugs as the predictors most strongly associated with recurrent falls. Female gender, living alone, past fractures, inactivity, body height, and use of analgetics proved to be the predictors most strongly associated with fractures. The probabilities of recurrent falls were 4.7% (95% CI, 2.9–7.5%) to 59.2% (95% CI, 24.1–86.9%) with zero to four predictors, respectively. The probability of fractures ranged from 0.0% (95% CI, 0.0–0.4%) without any of the identified predictors to 12.9% (95% CI, 4.4–32.2%) with all six predictors present. Our study shows that the risk of recurrent falls and of fractures can be predicted using up to, respectively, four and six easily measurable predictors. This study emphasizes the importance of impaired mobility and inactivity as predictors for falls and fractures.
Persistence of Ca2+-Sensing Receptor Expression in Functionally Active, Long-Term Human Parathyroid Cell Cultures
Authors: Roussanne Marie-Cécile , Gogusev Jean , Hory Bernard , Duchambon Patricia , Souberbielle Jean Claude , Nabarra Bernadette , Pierrat Denise , Sarfati Emile , Drüeke Tilman , Bourdeau Agnès 
Published: April 2006

Abstract
An original human parathyroid cell culture model from uremic patients with II° hyperparathyroidism has been developed, with its main feature being long-term functionally active viability up to 5 months, as assessed by persistent responsiveness to changes of extracellular Ca2+ concentrations ([Ca2+]e). In addition to the inhibitory effect of increasing [Ca2+]e, increasing extracellular phosphate exerted a biphasic effect on parathyroid hormone (PTH) secretion. The presence of the Ca2+-sensing receptor (CaR), on which depends the response to [Ca2+]e and its persistence, has been demonstrated in our culture system both by direct detection and by inhibition of its activity. CaR protein was detected by Western blot analysis with a specific anti-CaR antibody. CaR gene transcripts have been identified by reverse transcription-polymerase chain reaction analysis. mRNA (by in situ hybridization) and protein (by immunocytochemistry) expression were detected for both CaR and PTH. Adding a specific anti-CaR antibody to the medium induced a marked reduction of low [Ca2+]e-stimulated PTH release, which decreased to levels equivalent to those obtained in high [Ca2+]e medium. The described long-term functionality could be due to several factors, including the clustered cell type of culture yielded by our preparation procedure, the growth characteristics of hyperplastic uremic tissue, and the use of a phosphate-rich medium. The present model, because of its long-term functionality, is a unique tool for the exploration of PTH synthesis and secretion and for studies of parathyroid cell growth in vitro.
Do Dietary Calcium and Age Explain the Controversy Surrounding the Relationship Between Bone Mineral Density and Vitamin D Receptor Gene Polymorphisms?
Authors: Ferrari S. L. , Dr. Rizzoli R. , Slosman D. O. , Bonjour J.-P. 
Published: April 2006

Abstract
Whether vitamin D receptor (VDR) gene polymorphisms are associated with osteoporosis is highly controversial. The relationship between VDR gene polymorphisms and bone mineral density (BMD) might, however, be modified by age-related and/or environmental factors. We studied the potential association between BMD and VDR genotypes in females from prepuberty to premenopause and prospectively investigated the interaction of VDR genotypes with dietary calcium and BMD changes during childhood. Bsm I VDR gene polymorphisms and BMD at the lumbar spine (LS) and femur (neck [FN] and midshaft [FS]) were assessed in 369 healthy Caucasian females, aged 7–56 years (143 prepubertal girls, 54 peri- and postpubertal adolescents, and 172 premenopausal adults). Femoral trochanter (FT) and distal radius BMD (metaphysis and diaphysis) were also measured in 101 of the prepubertal girls who participated in a 1-year, double-blind, randomized study of calcium supplementation (850 mg/day) versus placebo on bone mineral mass accrual. Among all females, 150 (40.7%) had bb, 167 (45.3%) Bb, and 52 (14%) BB VDR genotypes. In prepubertal and adolescent girls altogether, LS BMD (Z scores) was associated with VDR genotypes and was significantly lower in BB than in Bb or bb subjects. Trends for a similar difference were also detected at the FN level as well as on the mean BMD (Z scores) of the three sites measured (LS, FN, and FS). By contrast, no BMD differences were detectable among VDR genotypes in the adults. In 101 prospectively studied prepubertal girls, calcium supplementation significantly increased BMD at most skeletal sites, except LS. After segregation for VDR genotypes (40 bb, 47 Bb, and 14 BB), a significant calcium effect was present in Bb but not bb girls, whereas in BB girls there was a positive but nonsignificant trend for a calcium effect. Moreover, dietary calcium intake was significantly correlated with BMD changes at various independent bone sites in Bb girls but not in bb girls. In contrast, BMD gain in bb girls appeared to be higher than among the other genotypes when the dietary calcium intake was low, i.e., in the absence of calcium supplements. BMD was significantly associated with VDR gene polymorphisms only before puberty, BB girls having significantly lower BMD (Z scores) than the other genotypes. By increasing dietary calcium intake, BMD accrual was increased in Bb and possibly BB prepubertal girls, whereas bb subjects had the highest spontaneous BMD accrual and remained unaffected by calcium supplements. Taking into account complex interactions between VDR gene polymorphisms and environmental factors, including calcium intake, may thus help to understand the discordant relationships between BMD and VDR gene polymorphisms.
Identification of a Novel Isoform of Mouse Dentin Matrix Protein 1: Spatial Expression in Mineralized Tissues
Authors: Dr. Macdougall Mary , Gu Ting Ting , Luan Xinghong , Simmons Darrin , Chen Jinkun 
Published: April 2006

Abstract
Dentin matrix protein 1 (Dmp1) is an acidic phosphoprotein first identified by cDNA cloning from a rat tooth library. Northern blot hybridization of a variety of tissues detected Dmp1 mRNAs only in odontoblasts, suggesting that this protein was odontoblast specific. In situ hybridization studies showed expression of Dmp1 in odontoblasts with transient expression in secretory ameloblasts. The purpose of this study was to isolate and characterize a mouse Dmp1 cDNA and determine its spatial expression pattern related to other mineralizing tissues. A mouse molar cDNA library was screened with a32P-labeled Dmp1 polymerase chain reaction amplification product in order to isolate a full-length clone. DNA sequence analysis of the largest mouse Dmp1 cDNA (2802 base pairs [bp]) revealed an open reading frame of 1509 nucleotides encoding a 503 amino acid protein with a single polyadenylation signal. Comparison with rat and bovine Dmp1 sequence showed high homology and the identification of a 45 bp (15 amino acid) insert, representing an alternative spliced mRNA. This 45 bp segment was shown to represent a small exon by DNA analysis of a mouse genomic Dmp1 clone. In situ hybridization studies revealed a much broader Dmp1 tissue expression pattern than previously reported. Dmp1 transcripts were detected in the odontoblast and ameloblasts, osteoblasts, and cementoblasts. Our data indicate that Dmp1 is alternatively spliced, and the primary full-length transcript contains a 45 bp insert which is encoded by a small exon. Therefore, Dmp1 is not a tooth-specific protein but rather is expressed in a number of mineralizing tissues including enamel, bone, and cementum.
Exercise Before Puberty May Confer Residual Benefits in Bone Density in Adulthood: Studies in Active Prepubertal and Retired Female Gymnasts
Authors: Bass S. , Pearce G. , Bradney M. , Hendrich E. , Delmas Pierre D. , Harding A. , Seeman E. 
Published: April 2006

Abstract
Exercise during growth may contribute to the prevention of osteoporosis by increasing peak bone mineral density (BMD). However, exercise during puberty may be associated with primary amenorrhea and low peak BMD, while exercise after puberty may be associated with secondary amenorrhea and bone loss. As growth before puberty is relatively sex hormone independent, are the prepubertal years the time during which exercise results in higher BMD? Are any benefits retained in adulthood? We measured areal BMD (g/cm2) by dual-energy X-ray absorptiometry in 45 active prepubertal female gymnasts aged 10.4 ± 0.3 years (mean ± SEM), 36 retired female gymnasts aged 25.0 ± 0.9 years, and 50 controls. The results were expressed as a standardized deviation (SD) or Z score adjusted for bone age in prepubertal gymnasts and chronological age in retired gymnasts. In the cross-sectional analyses, areal BMD in the active prepubertal gymnasts was 0.7–1.9 SD higher at the weight-bearing sites than the predicted mean in controls (p &lt; 0.01). The Z scores increased as the duration of training increased (r = 0.32–0.48, p ranging between &lt;0.04 and &lt;0.002). During 12 months, the increase in areal BMD (g/cm2/year) of the total body, spine, and legs in the active prepubertal gymnasts was 30–85% greater than in prepubertal controls (all p &lt; 0.05). In the retired gymnasts, the areal BMD was 0.5–1.5 SD higher than the predicted mean in controls at all sites, except the skull (p ranging between &lt;0.06 and &lt;0.0001). There was no diminution across the 20 years since retirement (mean 8 ± 1 years), despite the lower frequency and intensity of exercise. The prepubertal years are likely to be an opportune time for exercise to increase bone density. As residual benefits are maintained into adulthood, exercise before puberty may reduce fracture risk after menopause.
Role of Nitric Oxide and Prostaglandins in Mechanically Induced Bone Formation
Authors: Chow J. W. M. , Fox S. W. , Lean J. M. , Chambers T. J. 
Published: April 2006

Abstract
We have previously shown that prostaglandins (PG) and nitric oxide (NO) are required in the induction of bone formation by mechanical stimulation. We therefore tested the ability of NO donors, S-nitroso-N-acetyl-D,L-penicillamine (SNAP), and S-nitroso-glutathione (GSNO) to mimic or augment the osteogenic response of bone to a minimal mechanical stimulus. In rats administered vehicle or the vasodilator hydralazine, stimulation of the 8th caudal vertebra increased bone formation. In animals treated with SNAP or GSNO, there was significant potentiation of this osteogenic response. The bone formation rate in nonloaded vertebrae was unaffected by administration of the NO donors. We also found that while inhibition of either PG or NO production at the time of loading caused a partial suppression of c-fos mRNA expression in the loaded vertebrae, administration of indomethacin and NG-monomethyl-L-arginine together markedly suppressed c-fos expression. This suggests that although both PG and NO are required in mechanically induced osteogenesis, they appear to be generated largely independently of each other. Moreover, while exogenous NO potentiates the stimulatory effect of mechanical loading on bone formation, the lack of effect in nonloaded vertebrae suggests that NO is necessary but not sufficient for induction of bone formation.
Vitamin D Receptor Gene Start Codon Polymorphisms (FokI) and Bone Mineral Density: Interaction with Age, Dietary Calcium, and 3′-End Region Polymorphisms
Authors: Ferrari Serge , Rizzoli René , Manen Danielle , Slosman Daniel , Bonjour Jean-Philippe 
Published: April 2006

Abstract
Osteoporosis is a polygenic disease, whose determining loci have not yet been identified. Vitamin D receptor (VDR) gene polymorphisms in the 3′-end region (as determined by the enzymes BsmI and ApaI) have been inconsistently associated with bone mineral mass. More recently, VDR start codon polymorphisms (as determined by the enzyme FokI) have been found to be related to adult bone mineral density (BMD) in pre- and postmenopausal American women. We investigated the association between BMD and FokI genotypes in premenopausal European–Caucasian women as well as in prepubertal girls from the same genetic background and examined the interaction with VDR 3′-end region polymorphisms and with dietary calcium intake. Areal BMD (g/cm2) was measured by dual-energy X-ray absorptiometry at the level of the lumbar spine, femoral neck, and femoral shaft in 177 healthy premenopausal women (age range, 18.7–56.0 years) as well as in 155 prepubertal girls (age range, 6.6–11.4 years). Genotyping for FokI, BsmI, and ApaI VDR polymorphisms was performed using polymerase chain reaction methods. FokI genotype–dietary calcium interaction was cross-sectionally analyzed in all subjects and longitudinally in 103 prepubertal girls enrolled in a calcium intervention trial. The prevalence of FokI VDR gene polymorphisms in this cohort was 15% for ff, 50% for Ff, and 35% for FF. In the whole cohort of premenopausal women or prepubertal girls, no significant association was found between FokI VDR gene polymorphisms and BMD, even adjusted for age (Z score), weight, height, and calcium intake. Further analysis of FokI VDR gene polymorphisms and dietary calcium intake suggested a possible interaction in BMD determination, since a trend for an association with FokI genotypes was more evident at high than low calcium intake in both cross-sectional and longitudinal studies. Furthermore, cross-genotyping FokI and either BsmI or ApaI VDR polymorphisms suggested that the ff genotype was associated with a significantly lower lumbar spine BMD in bb and aa prepubertal girls. FokI VDR gene polymorphisms were not significantly associated with BMD in healthy European-Caucasian females. However, cross-genotyping of the VDR 3′-end and start codon polymorphic regions may provide a further insight into the complex determination of BMD.
Characterization of Aromatase and 17β-Hydroxysteroid Dehydrogenase Expression in Rat Osteoblastic Cells
Authors: Eyre Louise J. , Bland Rosemary , Bujalska Iwona J. , Sheppard Michael C. , Stewart Paul M. , Hewison Martin 
Published: April 2006

Abstract
Postmenopausal loss of 17β-estradiol (E2) in women is associated with decreased bone mineral density and increased susceptibility to osteoporotic bone fracture. These changes in bone status are assumed to be due to circulating levels of the hormone; therapeutic replacement of E2 can alleviate the bone disease. However, recent reports have shown that human osteoblastic (OB) cells are able to synthesize estrogens locally, via expression of the enzyme aromatase. In this study, we have characterized the expression and activity of aromatase and 17β-hydroxysteroid dehydrogenase (17β-HSD) in rat OB cell lines. Aromatase activity in ROS 17/2.8, ROS 25/1, and UMR 106 cells was similar to that shown in human OB cells, with the highest levels of activity observed in the more differentiated ROS 17/2.8 cells (Vmax = 45 pmol/h/mg of protein). The rat OB cells also showed 17β-HSD activity, with the predominant metabolism in all three cell lines being estrone (E1) to E2. As with aromatase, the highest activity was observed in ROS 17/2.8 cells (Vmax = 800 pmol/h/mg of protein). Northern analyses indicated the variable presence of transcripts corresponding to the type 1, 2, 3, and 4 isoforms of 17β-HSD. Further analysis of androstenedione metabolism indicated that the net effect of aromatase and 17β-HSD activity varied with cell type and culture treatment. All three OB cell lines were able to synthesize E1, E2, and testosterone from androstenedione, although activity varied between OB cell types. Regulatory effects were observed with 1,25-dihydroxyvitamin D3 (positive) and dexamethasone (negative). These data suggest that local synthesis of sex hormones is an important function of OB cells and may play a key role in the modulation of bone turnover independent of circulating hormone concentrations.