bluuebunny/crossref_metadata_2025 huggingface dataset:
The role side effects play in the choice of antiepileptic therapy in brain tumor-related epilepsy: a comparative study on traditional antiepileptic drugs versus oxcarbazepine
Authors: Maschio Marta , Dinapoli Loredana , Vidiri Antonello , Pace Andrea , Fabi Alessandra , Pompili Alfredo , Carapella Maria Carmine , Jandolo Bruno
Published: May 2009

Background

Seizure control doesn't represent the only challenging goal in patients with brain tumor-related epilepsy. Side effects have often taken precedence for patients' quality of life.

Methods

We performed an observational retrospective study on patients with brain tumor-related epilepsy: 35 who had assumed oxcarbazepine monotherapy and 35 patients who had undergone treatment with traditional antiepileptic drugs. Primary variable of efficacy was the mean seizure frequency per month and safety variables were the drop-out for side effects and total incidence of side effects. We applied the Propensity Score technique to minimize selection bias.

Results

Our results showed a similar efficacy of oxcarbazepine and traditional antiepileptic drugs over time, but the difference in safety and tolerability between the two groups was significant: traditional AEDs caused more side effects, both serious and non serious.

Conclusion

This study highlights the importance of taking into consideration not only seizure control but also the appearance of side effects when choosing antiepileptic drugs in this patients population.
Lessons learned during down referral of antiretroviral treatment in Tete, Mozambique
Authors: Decroo Tom , Panunzi Isabella , das Dores Carla , Maldonado Fernando , Biot Marc , Ford Nathan , Chu Kathryn
Published: May 2009

As sub‐Saharan African countries continue to scale up antiretroviral treatment, there has been an increasing emphasis on moving provision of services from hospital level to the primary health care clinic level. Delivery of antiretroviral treatment at the clinic level increases the number of entry points to care, while the greater proximity of services encourages retention in care.

In Tete City, Mozambique, patients on antiretrovirals were rapidly down referred from a provincial hospital to four urban clinics in large numbers without careful planning, resulting in a number of patients being lost to follow‐up.

We outline some key lessons learned to support down referral, including the need to improve process management, clinic infrastructure, monitoring systems, and patient preparation. Down referral can be avoided by initiating patients' antiretroviral treatment at clinic level from the outset.
Progesterone Activates a Progesterone Receptor Membrane Component 1-Dependent Mechanism That Promotes Human Granulosa/Luteal Cell Survival But Not Progesterone Secretion
Authors: Peluso John J. , Liu Xiufang , Gawkowska Anna , Johnston-MacAnanny Erika
Published: May 2009

Context: Progesterone (P4) promotes its own secretion and the survival of human granulosa/luteal (GL) cells.

Objective: The objective of these studies was to determine whether progesterone receptor membrane component-1 (PGRMC1) mediates P4’s actions.

Design: In vitro studies were conducted on GL cells from women undergoing in vitro fertilization and GL5 cells, which are derived from GL cells.

Setting and Patients: GL cells were obtained from women undergoing fertility treatment at a university-based clinic and used for in vitro studies.

Main Outcome Measures: PCR, Western blot, and immunocytochemistry were used to detect various progestin binding proteins. 3H-P4 binding kinetics were assessed on partially purified PGRMC1. Apoptosis was determined after culture by either TUNEL or DAPI staining. P4 was measured by an ELISA assay. PGRMC1 was depleted using small interfering RNA.

Results: GL and GL5 cells expressed several P4 binding proteins including the nuclear progesterone receptor (PGR), progestin/adipoQ receptors (PAQR 7, 8, and 5) and PGRMC1. Ligand binding studies revealed that both P4 and the progestin, R5020, bound PGRMC1 with an EC50 of approximately 10 nm. Interestingly, P4 inhibited apoptosis at concentrations in the 10 nm range, whereas R5020 stimulated P4 secretion at concentrations of at lease 16 μm. Depleting PGRMC1 attenuated P4’s antiapoptotic action but failed to influence R5020-induced P4 secretion.

Conclusions: These studies conclusively demonstrate that in human GL cells PGRMC1 functions as a receptor through which P4 activates a signal cascade that prevents apoptosis. In contrast, PGRMC1 does not mediate P4’s ability to acutely promote its own secretion.
Mutation Analysis of the Muscarinic Cholinergic Receptor Genes in Isolated Growth Hormone Deficiency Type IB
Authors: Mohamadi Ali , Martari Marco , Holladay Cindy D. , Phillips John A. , Mullis Primus E. , Salvatori Roberto
Published: May 2009

Background: Isolated GH deficiency (IGHD) is familial in 5–30% of patients. The most frequent form (IGHD-IB) has autosomal recessive inheritance, and it is known that it can be caused by mutations in the GHRH receptor (GHRHR) gene or in the GH gene. However, most forms of IGHD-IB have an unknown genetic cause. In normal subjects, muscarinic cholinergic stimulation causes an increase in pituitary GH release, whereas its blockade has the opposite effect, suggesting that a muscarinic acetylcholine receptor (mAchR) is involved in stimulating GH secretion. Five types of mAchR (M1–M5) exist. A transgenic mouse in which the function of the M3 receptor was selectively ablated in the central nervous system has isolated GH deficiency similar to animals with defective GHRH or GHRHR gene.

Objective: We hypothesized that mAchR mutations may cause a subset of familial IGHD.

Patients/Methods: After confirming the expression of M1–M5 receptor mRNA in human hypothalamus, we analyzed the index cases of 39 families with IGHD-IB for mutations in the genes encoding for the five receptors. Coding sequences for each of the five mAchRs were subjected to direct sequencing.

Results: In one family, an affected member was homozygous for a M3 change in codon 65 that replaces valine with isoleucine (V65I). The V65I receptor was expressed in CHO cells where it had normal ability to transmit methacholine signaling.

Conclusion: mAchR mutations are absent or rare (less than 2.6%) in familial IGHD type IB.
Sizing up the nucleus: nuclear shape, size and nuclear-envelope assembly
Authors: Webster Micah , Witkin Keren L. , Cohen-Fix Orna
Published: May 2009

The nucleus is one of the most prominent cellular organelles, yet surprisingly little is known about how it is formed, what determines its shape and what defines its size. As the nuclear envelope (NE) disassembles in each and every cell cycle in metazoans, the process of rebuilding the nucleus is crucial for proper development and cell proliferation. In this Commentary, we summarize what is known about the regulation of nuclear shape and size, and highlight recent findings that shed light on the process of building a nucleus, including new discoveries related to NE assembly and the relationship between the NE and the endoplasmic reticulum (ER). Throughout our discussion, we note interesting aspects of nuclear structure that have yet to be resolved. Finally, we present an idea – which we refer to as `the limited flat membrane hypothesis' – to explain the formation of a single nucleus that encompasses of all of the cell's chromosomes following mitosis.
Endothelial barrier stabilization by a cyclic tandem peptide targeting VE-cadherin transinteraction in vitro and in vivo
Authors: Heupel Wolfgang-Moritz , Efthymiadis Athina , Schlegel Nicolas , Müller Thomas , Baumer Yvonne , Baumgartner Werner , Drenckhahn Detlev , Waschke Jens
Published: May 2009

Inflammatory stimuli result in vascular leakage with potentially life threatening consequences. As a key barrier component, loss of vascular endothelial (VE-) cadherin-mediated adhesion often precedes endothelial breakdown. This study aimed to stabilize VE-cadherin transinteraction and endothelial barrier function using peptides targeting the VE-cadherin adhesive interface. After modelling the transinteracting VE-cadherin structure, an inhibiting single peptide (SP) against a VE-cadherin binding pocket was selected, which specifically blocked VE-cadherin transinteraction as analyzed by single molecule atomic force microscopy (AFM). The tandem peptide (TP) consisting of two SP sequences in tandem was designed to strengthen VE-cadherin adhesion by simultaneously binding and cross-bridging two interacting cadherin molecules. Indeed, in AFM experiments TP specifically rendered VE-cadherin transinteraction resistant against an inhibitory monoclonal antibody. Moreover, TP reduced VE-cadherin lateral mobility and enhanced binding of VE-cadherin-coated microbeads to cultured endothelial cells, but acted independently of the actin cytoskeleton. TP also stabilized endothelial barrier properties against the Ca2+ ionophore A23187 and the inhibitory antibody. Finally, TP abolished endothelial permeability increase induced by tumour necrosis factor-α in microperfused venules in vivo. Stabilization of VE-cadherin adhesion by cross-bridging peptides may therefore be a novel therapeutic approach for the treatment of vascular hyperpermeability.
Roles of theDrosophilaNudE protein in kinetochore function and centrosome migration
Authors: Wainman Alan , Creque Jacklyn , Williams Byron , Williams Erika V. , Bonaccorsi Silvia , Gatti Maurizio , Goldberg Michael L.
Published: May 2009

We examined the distribution of the dynein-associated protein NudE in Drosophila larval brain neuroblasts and spermatocytes, and analyzed the phenotypic consequences of a nudE null mutation. NudE can associate with kinetochores, spindles and the nuclear envelope. In nudE mutant brain mitotic cells, centrosomes are often detached from the poles. Moreover, the centrosomes of mutant primary spermatocytes do not migrate from the cell cortex to the nuclear envelope, establishing a new role for NudE. In mutant neuroblasts, chromosomes fail to congress to a tight metaphase plate, and cell division arrests because of spindle assembly checkpoint (SAC) activation. The targeting of NudE to mitotic kinetochores requires the dynein-interacting protein Lis1, and surprisingly Cenp-meta, a Drosophila CENP-E homolog. NudE is non-essential for the targeting of all mitotic kinetochore components tested. However, in the absence of NudE, the `shedding' of proteins off the kinetochore is abrogated and the SAC cannot be turned off, implying that NudE regulates dynein function at the kinetochore.
Analysis of circumferentially welded thin-walled cylinders to study the effects of tack weld orientations and joint root opening on residual stress fields
Authors: Dar N U , Qureshi E M , Malik A M , Hammouda M M I , Azeem R A
Published: May 2009

In recent years, the demand for resilient welded structures with excellent in-service load-bearing capacity has been growing rapidly. The operating conditions (thermal and/or structural loads) are becoming more stringent, putting immense pressure on welding engineers to secure excellent quality welded structures. The local, non-uniform heating and subsequent cooling during the welding processes cause complex thermal stress—strain fields to develop, which finally leads to residual stresses, distortions, and their adverse consequences. Residual stresses are of prime concern to industries producing weld-integrated structures around the globe because of their obvious potential to cause dimensional instability in welded structures, and contribute to premature fracture/failure along with significant reduction in fatigue strength and in-service performance of welded structures. Arc welding with single or multiple weld runs is an appropriate and cost-effective joining method to produce high-strength structures in these industries. Multi-field interaction in arc welding makes it a complex manufacturing process. A number of geometric and process parameters contribute significant stress levels in arc-welded structures. In the present analysis, parametric studies have been conducted for the effects of a critical geometric parameter (i.e. tack weld) on the corresponding residual stress fields in circumferentially welded thin-walled cylinders. Tack weld offers considerable resistance to the shrinkage, and the orientation and size of tacks can altogether alter stress patterns within the weldments. Hence, a critical analysis for the effects of tack weld orientation is desirable.
On the evaluation of in-plane elastic behaviour of woven fibre metal laminates under uniform loading
Authors: Sepiani H A , Afaghi-Khatibi A , Mosavi M
Published: May 2009

This article deals with the non-linear behaviour of woven fibre metal laminates (WFMLs). A theoretical micromechanical model has been proposed for the plain-wave fabric-reinforced flexible composite with two surface-bonded metal layers under biaxial loading. The constitutive equations are derived through a strain energy approach and energy variation theorem based on the microstructure of composites. The modelling strategy starts with a geometrical description of the yarn and the unit cell and fibres are assumed to be in a sinusoidal shape. Meanwhile, a simple and conventional analytical technique is applied to predict the tensile properties of WFMLs. Stress—strain behaviour of such structure plates under uniform uniaxial loading are illustrated in figures. The proposed integrated micromechanical model shows excellent agreement with the three-dimensional finite-element results. Finally, a parametric study is performed using the presented models to investigate the effect of thickness of metal layers on the elastic properties of the composite.
Dynamic analysis of disc spring effects on the contact pressure of the collet—spindle interface in a high-speed spindle system
Authors: Chen Y S , Chiu C C , Cheng Y D
Published: May 2009

In a high-speed gas spindle, the drawbar force required to hold the drill bit is produced by the deformation of disc spring stacks. This drawbar force, applied to the collet—spindle interface, generates a contact pressure on the collet to hold the drill bit in position. Thus, the behaviour of the collet—spindle interface is critical to machining quality. Accordingly, this study investigated how disc spring characteristics affect the collet—spindle interface in a high-speed spindle. Typi-cally, the drawbar force will decrease following the deformation of disc springs resulting from the effects of centrifugal force at high rotational speeds. This effect must be considered, especially in high-speed spindle applications. This study first measured the drawbar force experimentally and compared these results with theoretical and finite-element analysis (FEA) data under static conditions (i.e. no rotation). Having obtained satisfactory agreement among these data, the FEA was extended to a further investigation. Properties of the collet—spindle contact interface were analysed, given changes in rotational speed from 0 to 300 000 r/min under various disc spring deflections, various friction coefficients between the disc springs and their support, and distinct taper angles at the collet—spindle interface. All of these conditions are discussed here. These essential parameters are believed to cover much of the design of high-speed gas spindle systems.
Cross Sectional Survey of the Scottish General Public's Awareness of, Views on, and Attitudes Toward Nonmedical Prescribing
Authors: Stewart Derek C , George Johnson , Diack H Lesley , Bond Christine M , Mccaig Dorothy J , Cunningham It Scott , Munro Kim , Pfleger David
Published: May 2009

Background

Nonmedical (ie, nonphysician) prescribing is a key development in the UK that has brought about many changes in prescribing policy and practice. Systematic research into the views of the general public toward such developments is limited.

Objective

To determine the awareness of, views on, and attitudes of members of the Scottish general public toward nonmedical prescribing, with an emphasis on pharmacist prescribing.

Methods

A questionnaire was mailed in November 2006 to a random sample of 5000 members of the general public in Scotland aged 18 and over, obtained from the UK electoral roll. The questionnaire contained items on awareness of nonmedical prescribing, levels of comfort with specific health professionals, and attitudes toward pharmacist prescribing.

Results

Response rate was 37.1%. More than half of the individuals who responded were taking prescribed drugs. Nine hundred and seventy-eight (56.6%) were aware that trained health professionals could write prescriptions for medicines previously only prescribed by physicians. Awareness was associated with: increasing age (p < 0.001), having a health professional in their immediate family (p < 0.001), self-rated general health (p < 0.005), and a higher education level (p < 0.01). In logistic regression, all factors were retained as independent predictors of awareness (p < 0.001). Comfort levels for nonmedical prescribing were highest for pharmacists (median 4, IQR 3–5 [1 = low, 5 = high]), closely followed by nurses, and lowest for radiographers (median 2, IQR 1–4) (p <0.001). While more than half of the respondents supported pharmacists having a prescribing role, fewer felt that pharmacists should prescribe the same range of drugs as physicians. There were concerns about lack of privacy in a pharmacy, despite acknowledging its enhanced convenience.

Conclusions

Our results indicate that more than half of the respondents were aware of nonmedical prescribing. A higher proportion was more comfortable with prescribing by pharmacists and nurses than with other healthcare professionals. Several issues relating to aspects of clinical governance were highlighted, specifically education and data handling.
A Short Treatment With an Antibody to Sclerostin Can Inhibit Bone Loss in an Ongoing Model of Colitis
Authors: Eddleston Alison , Marenzana Massimo , Moore Adrian R , Stephens Paul , Muzylak Mariusz , Marshall Diane , Robinson Martyn K
Published: May 2009

Chronic inflammation leads to bone loss, and increased fracture rates have been reported in a number of human chronic inflammatory conditions. The study reported here investigates the skeletal effects of dosing a neutralizing antibody to the bone regulatory protein sclerostin in a mouse model of chronic colitis. When dosed prophylactically, an antibody to sclerostin (Scl-AbI) did not reduce the weight loss or histological changes associated with colitis but did prevent inflammation-induced bone loss. At the end of the experiment, Scl-AbI–treated animals had a significantly higher femoral BMD (+27%, p < 0.05) than control antibody (Cntrl-Ab)-treated animals. In a second experiment, treatment with Scl-AbI was delayed until colitis had developed, by which time the mechanical properties of femurs in colitic animals were significantly worse than those of healthy age-matched control mice (maximum load, −26%, p < 0.05; energy, −37%, p < 0.05; ultimate strength, −33%, p < 0.05; elastic modulus, −17%, p < 0.05). A short treatment with Scl-AbI halted bone loss and reversed the decline of both intrinsic and extrinsic mechanical properties of the femur such that, after 19 days of treatment, the bone mechanical properties in the Scl-AbI–treated animals were not significantly different from those of noncolitic age-matched controls. Serum markers of bone formation and resorption suggested that the antibody to sclerostin stimulated osteoblast activity and inhibited osteoclast-mediated bone resorption.
Effects of hPTH(1-34) Infusion on Circulating Serum Phosphate, 1,25-Dihydroxyvitamin D, and FGF23 Levels in Healthy Men
Authors: Burnett-Bowie Sherri-Ann M , Henao Maria P , Dere Melissa E , Lee Hang , Leder Benjamin Z
Published: May 2009

Fibroblast growth factor 23 (FGF23) promotes phosphaturia and suppresses 1,25-dihydroxyvitamin D [1,25(OH)2D] production. PTH also promotes phosphaturia, but, in contrast, stimulates 1,25(OH)2D production. The relationship between FGF23 and PTH is unclear, and the acute effect of pharmacologically dosed PTH on FGF23 secretion is unknown. Twenty healthy men were infused with human PTH(1-34) [hPTH(1-34)] at 44 ng/kg/h for 24 h. Compared with baseline, FGF23, 1,25(OH)2D, ionized calcium (iCa), and serum N-telopeptide (NTX) increased significantly over the 18-h hPTH(1-34) infusion (p < 0.0001), whereas serum phosphate (PO4) transiently increased and then returned to baseline. FGF23 increased from 35 ± 10 pg/ml at baseline to 53 ± 20 pg/ml at 18 h (p = 0.0002); 1,25(OH)2D increased from 36 ± 16 pg/ml at baseline to 80 ± 33 pg/ml at 18 h (p < 0.0001); iCa increased from 1.23 ± 0.03 mM at baseline to 1.46 ± 0.05 mM at hour 18 (p < 0.0001); and NTX increased from 17 ± 4 nM BCE at baseline to 28 ± 8 nM BCE at peak (p < 0.0001). PO4 was 3.3 ± 0.6 mg/dl at baseline, transiently rose to 3.7 ± 0.4 mg/dl at hour 6 (p = 0.016), and then returned to 3.4 ± 0.5 mg/dl at hour 12 (p = 0.651). hPTH(1-34) infusion increases endogenous 1,25(OH)2D and FGF23 within 18 h in healthy men. Whereas it is possible that the rise in PO4 contributed to the observed increase in FGF23, the increase in 1,25(OH)2D was more substantial and longer sustained than the change in serum phosphate. Given prior data that suggest that neither PTH nor calcium stimulate FGF23 secretion, these data support the assertion that 1,25(OH)2D is a potent physiologic stimulator of FGF23 secretion.
Bilateral Fractures of the Femur Diaphysis in a Patient With Rheumatoid Arthritis on Long-Term Treatment With Alendronate: Clues to the Mechanism of Increased Bone Fragility
Authors: Somford Matthijs P , Draijer Frits W , Thomassen Bregje JW , Chavassieux Pascale M , Boivin Georges , Papapoulos Socrates E
Published: May 2009

Unusual fractures of the femur diaphysis have been reported in patients treated with alendronate and, although no causal relationship has been established, excessive suppression of bone turnover and length of treatment with alendronate have been implicated in their pathogenesis. We report here clinical, biochemical, and radiological findings of a patient with rheumatoid arthritis and multiple risk factors for fractures who was treated with alendronate for 8 yr and developed spontaneous bilateral subtrochanteric/diaphyseal fractures. Bone biopsies obtained form the iliac crest and the femur showed decreased bone formation with histomorphometric evidence of markedly increased bone resorption at the femur. These results show for the first time that an imbalance between bone resorption and bone formation at the affected bone is associated with the occurrence of these atypical femur fractures. The cause of this imbalance is currently unknown, and further studies of the epidemiology and pathogenesis of diaphyseal femur fractures are warranted.
Vps33a Mediates RANKL Storage in Secretory Lysosomes in Osteoblastic Cells
Authors: Kariya Yoshiaki , Honma Masashi , Aoki Shigeki , Chiba Atsushi , Suzuki Hiroshi
Published: May 2009

Previous studies have indicated that the amount of RANKL expressed on the cell surface of osteoblasts or bone marrow stromal cells (BMSCs) is considered an important factor determining the extent of osteoclast activation. However, subcellular trafficking of RANKL and its regulatory mechanisms in osteoblastic cells is still unclear. In this study, we showed that RANKL is predominantly localized in lysosomal organelles, but little is found on the cell surface of osteoblastic cells. We also showed that RANKL is relocated to the plasma membrane in response to stimulation with RANK-Fc–coated beads, indicating that the lysosomal organelles where RANKL is localized function as secretory lysosomes. In addition, using a protein pull-down method, we identified vacuolar protein sorting (Vps)33a as interacting with the cytoplasmic tail of RANKL. Furthermore, knockdown of Vps33a expression reduced the lysosomal storage of RANKL and caused the accumulation of newly synthesized RANKL in the Golgi apparatus, indicating that Vps33a is involved in transporting RANKL from the Golgi apparatus to secretory lysosomes. We also showed that suppression of Vps33a affects the cell surface expression level of RANKL and disrupts the regulated behavior of RANKL. These results suggest that RANKL storage in secretory lysosomes is important to control osteoclast activation and to maintain bone homeostasis.
LPS-Induced Inhibition of Osteogenesis Is TNF-α Dependent in a Murine Tooth Extraction Model
Authors: Tomomatsu Nobuyoshi , Aoki Kazuhiro , Alles Neil , Soysa Niroshani S , Hussain Anower , Nakachi Hiroyuki , Kita Souma , Shimokawa Hitoyata , Ohya Keiichi , Amagasa Teruo
Published: May 2009

TNF-α is a major etiologic factor of inflammatory bone diseases such as periodontitis and rheumatoid arthritis. In addition, patients with metabolic diseases such as chronic heart disease and diabetes have significantly increased plasma levels of TNF-α. Several lines of evidence show inhibition of osteoblastogenesis by TNF-α in vitro. Therefore, bone formation and osteogenesis in these patients might be inhibited because of TNF-α. However, little is known about the inhibitory role of TNF-α in bone formation/osteogenesis in vivo. The purpose of this study was to investigate the role of TNF-α in osteogenesis using a murine tooth extraction model. Lipopolysaccharide (LPS) was injected subcutaneously into the calvariae of either wildtype (WT) or TNF-α–deficient (KO) mice. The left incisor was extracted 4 days after LPS injection. The measuring area was established as the tooth socket under the mesial root of the first molar. A significant increase in serum TNF-α levels after LPS injection was observed in WT mice. The BMD of the tooth socket was significantly decreased by LPS injection 21 days after extraction in WT but not in KO mice. Histomorphometric analysis showed a significant decrease in the mineral apposition rate after LPS injection, which appeared at an early stage in WT but not in KO mice. Injection of a peptide that blocked the TNF-α signaling pathway by preventing transmission of the NF-κB signal recovered the inhibition of osteogenesis observed after LPS injection. In conclusion, TNF-α might play a major role in LPS-induced inhibition of osteogenesis under inflammatory conditions.
Effects of Repetitive Loading on Bone Mass and Geometry in Young Male Tennis Players: A Quantitative Study Using MRI
Authors: Ducher Gaele , Daly Robin M , Bass Shona L
Published: May 2009

Pre- and early puberty seem to be the most opportune times for exercise to improve bone strength in girls, but few studies have addressed this issue in boys. This study investigated the site-, surface-, and maturity-specific exercise-induced changes in bone mass and geometry in young boys. The osteogenic effects of loading were analyzed by comparing the playing and nonplaying humeri of 43 male pre-, peri-, and postpubertal competitive tennis players 10–19 yr of age. Total bone area, medullary area, and cortical area were determined at the mid (40–50%) and distal humerus (60–70%) of both arms using MRI. Humeral bone mass (BMC) was derived from a whole body DXA scan. In prepubertal boys, BMC was 17% greater in the playing compared with nonplaying arm (p < 0.001), which was accompanied by a 12–21% greater cortical area, because of greater periosteal expansion than medullary expansion at the midhumerus and periosteal expansion associated with medullary contraction at the distal humerus. Compared with prepuberty, the side-to-side differences in BMC (27%) and cortical area (20–33%) were greater in peripuberty (p < 0.01). No differences were found between peri- and postpuberty despite longer playing history in the postpubertal players. The osteogenic response to loading was greater in peri- compared with prepubertal boys, which is in contrast with our previous findings in girls and may be caused by differences in training history. This suggests that the window of opportunity to improve bone mass and size through exercise may be longer in boys than in girls.
Improvements in Vertebral Body Strength Under Teriparatide Treatment Assessed In Vivo by Finite Element Analysis: Results From the EUROFORS Study
Authors: Graeff Christian , Chevalier Yan , Charlebois Mathieu , Varga Peter , Pahr Dieter , Nickelsen Thomas N , Morlock Michael M , Glüer Claus C , Zysset Philippe K
Published: May 2009

Monitoring of osteoporosis therapy based solely on DXA is insufficient to assess antifracture efficacy. Estimating bone strength as a variable closely linked to fracture risk is therefore of importance. Finite element (FE) analysis–based strength measures were used to monitor a teriparatide therapy and the associated effects on whole bone and local fracture risk. In 44 postmenopausal women with established osteoporosis participating in the EUROFORS study, FE models based on high-resolution CT (HRCT) of T12 were evaluated after 0, 6, 12, and 24 mo of teriparatide treatment (20 μg/d). FE-based strength and stiffness calculations for three different load cases (compression, bending, and combined compression and bending) were compared with volumetric BMD (vBMD) and apparent bone volume fraction (app. BV/TV), as well as DXA-based areal BMD of the lumbar spine. Local damage of the bone tissue was also modeled. Highly significant improvements in all analyzed variables as early as 6 mo after starting teriparatide were found. After 24 mo, bone strength in compression was increased by 28.1 ± 4.7% (SE), in bending by 28.3 ± 4.9%, whereas app. BV/TV was increased by 54.7 ± 8.8%, vBMD by 19.1 ± 4.0%, and areal BMD of L1–L4 by 10.2 ± 1.2%. When comparing standardized increases, FE changes were significantly larger than those of densitometry and not significantly different from app. BV/TV. The size of regions at high risk for local failure was significantly reduced under teriparatide treatment. Treatment with teriparatide leads to bone strength increases for different loading conditions of close to 30%. FE is a suitable tool for monitoring bone anabolic treatment in groups or individual patients and offers additional information about local failure modes. FE variables showed a higher standardized response to changes than BMD measurements, but further studies are needed to show that the higher response represents a more accurate estimate of treatment-induced fracture risk reduction.
Bone, Muscle, and Physical Activity: Structural Equation Modeling of Relationships and Genetic Influence With Age
Authors: Lang Dean H , Conroy David E , Lionikas Arimantas , Mack Holly A , Larsson Lars , Vogler George P , Vandenbergh David J , Blizard David A , McClearn Gerald E , Sharkey Neil A
Published: May 2009

Correlations among bone strength, muscle mass, and physical activity suggest that these traits may be modulated by each other and/or by common genetic and/or environmental mechanisms. This study used structural equation modeling (SEM) to explore the extent to which select genetic loci manifest their pleiotropic effects through functional adaptations commonly referred to as Wolff's law. Quantitative trait locus (QTL) analysis was used to identify regions of chromosomes that simultaneously influenced skeletal mechanics, muscle mass, and/or activity-related behaviors in young and aged B6×D2 second-generation (F2) mice of both sexes. SEM was used to further study relationships among select QTLs, bone mechanics, muscle mass, and measures of activity. The SEM approach provided the means to numerically decouple the musculoskeletal effects of mechanical loading from the effects of other physiological processes involved in locomotion and physical activity. It was found that muscle mass was a better predictor of bone mechanics in young females, whereas mechanical loading was a better predictor of bone mechanics in older females. An activity-induced loading factor positively predicted the mechanical behavior of hindlimb bones in older males; contrarily, load-free locomotion (i.e., the remaining effects after removing the effects of loading) negatively predicted bone performance. QTLs on chromosomes 4, 7, and 9 seem to exert some of their influence on bone through actions consistent with Wolff's Law. Further exploration of these and other mechanisms through which genes function will aid in development of individualized interventions able to exploit the numerous complex pathways contributing to skeletal health.
Alteration of RANKL-Induced Osteoclastogenesis in Primary Cultured Osteoclasts From SERCA2+/− Mice
Authors: Yang Yu-Mi , Kim Min Seuk , Son Aran , Hong Jeong Hee , Kim Kyung-Ho , Seo Jeong Taeg , Lee Syng-Ill , Shin Dong Min
Published: May 2009

RANKL is essential for the terminal differentiation of monocytes/marcrophages into osteoclasts. RANKL induces long-lasting oscillations in the intracellular concentration of Ca2+ ([Ca2+]i) only after 24 h of stimulation. These Ca2+ oscillations play a switch-on role in NFATc1 expression and osteoclast differentiation. Which Ca2+ transporting pathway is induced by RANKL to evoke the Ca2+ oscillations and its specific role in RANKL-mediated osteoclast differentiation is not known. This study examined the effect of a partial loss of sarco/endoplasmic reticulum Ca2+ ATPase type2 (SERCA2) on osteoclast differentiation in SERCA2 heterozygote mice (SERCA2+/−). The BMD in the tibias of SERCA2+/− mice increased >1.5-fold compared with wildtype mice (WT). RANKL-induced [Ca2+]i oscillations were generated 48 h after RANKL treatment in the WT mice but not in the SERCA2+/− bone marrow–derived macrophages (BMMs). Forty-eight hours after RANKL treatment, there was a lower level of NFATc1 protein expression and markedly reduced translocation of NFATc1 into the nucleus during osteoclastogenesis of the SERCA2+/− BMMs. In addition, RANKL treatment of SERCA2+/− BMMs incompletely induced formation of multinucleated cells, leading to reduced bone resorption activity. These results suggest that RANKL-mediated induction of SERCA2 plays a critical role in the RANKL-induced [Ca2+]i oscillations that are essential for osteoclastogenesis.
Enhanced Osteoclastogenesis Causes Osteopenia in Twisted Gastrulation-Deficient Mice Through Increased BMP Signaling
Authors: Sotillo Rodriguez Julio E. , Mansky Kim C. , Jensen Eric D. , Carlson Ann E. , Schwarz Toni , Pham Lan , MacKenzie BreAnne , Prasad Hari , Rohrer Michael D. , Petryk Anna , Gopalakrishnan Rajaram
Published: May 2009

The uncoupling of osteoblastic and osteoclastic activity is central to disorders such as osteoporosis, osteolytic malignancies, and periodontitis. Numerous studies have shown explicit functions for bone morphogenetic proteins (BMPs) in skeletogenesis. Their signaling activity has been shown in various contexts to be regulated by extracellular proteins, including Twisted gastrulation (TWSG1). However, experimental paradigms determining the effects of BMP regulators on bone remodeling are limited. In this study, we assessed the role of TWSG1 in postnatal bone homeostasis. Twsg1-deficient (Twsg1−/−) mice developed osteopenia that could not be explained by defective osteoblast function, because mineral apposition rate and differentiation markers were not significantly different compared with wildtype (WT) mice. Instead, we discovered a striking enhancement of osteoclastogenesis in Twsg1−/− mice, leading to increased bone resorption with resultant osteopenia. Enhanced osteoclastogenesis in Twsg1−/− mice was caused by increased cell fusion, differentiation, and function of osteoclasts. Furthermore, RANKL-mediated osteoclastogenesis and phosphorylated Smad1/5/8 levels were enhanced when WT osteoclasts were treated with recombinant BMP2, suggesting direct regulation of osteoclast differentiation by BMPs. Increase in detectable levels of phosphorylated Smad 1/5/8 was noted in osteoclasts from Twsg1−/− mice compared with WT mice. Furthermore, the enhanced osteoclastogenesis in Twsg1−/− mice was reversed in vitro in a dose-dependent manner with exposure to Noggin, a BMP antagonist, strongly suggesting that the enhanced osteoclastogenesis in Twsg1 mutants is attributable to increased BMP signaling. Thus, we present a novel and previously uncharacterized role for TWSG1 in inhibiting osteoclastogenesis through regulation of BMP activity.
Phosphate-Dependent Regulation of MGP in Osteoblasts: Role of ERK1/2 and Fra-1
Authors: Julien Marion , Khoshniat Solmaz , Lacreusette Aline , Gatius Maithé , Bozec Aline , Wagner Erwin F. , Wittrant Yohann , Masson Martial , Weiss Pierre , Beck Laurent , Magne David , Guicheux Jerome
Published: May 2009

Inorganic phosphate (Pi) and the matrix Gla protein (MGP) are key regulators of bone formation. We have recently shown that Pi upregulates MGP in growth plate chondrocytes, which may represent a negative feedback loop for the control of mineralization. Osteoblasts from Fra-1-deleted mice express low levels of MGP, whereas the expression of MGP is elevated in Fra-1 transgenic osteoblasts, suggesting a role for Fra-1 in MGP expression and bone formation. In this study, we aimed at deciphering the relationships between Pi and MGP in osteoblasts to determine the molecular mechanisms involved in the Pi-dependent regulation of MGP. In MC3T3-E1 cells and primary calvaria-derived osteoblasts, Pi increased MGP and Fra-1 expression at both the mRNA and protein levels. We also found that Pi enhanced the phosphorylation of ERK1/2. U0126 (MEK1/2 inhibitor) suppressed Pi-stimulated MGP and Fra-1 expression, indicating that ERK1/2 is required for Pi-dependent regulation of MGP and Fra-1. In addition, using in vitro DNA binding and chromatin immunoprecipitation assays, we showed that Fra-1 interacts with the MGP promoter in response to Pi in MC3T3-E1 cells. Finally, we found that in fra-1 knockdown MC3T3-E1 osteoblasts, the level of MGP expression is no more significantly upregulated by Pi. We further showed that primary osteoblasts from Fra-1-deficient mice failed to exhibit a Pi-dependent stimulation of MGP expression. These data show, for the first time, that Pi regulates MGP expression in osteoblasts through the ERK1/2-Fra-1 pathway.
Therapeutic Effects of Anti-FGF23 Antibodies in Hypophosphatemic Rickets/Osteomalacia
Authors: Aono Yukiko , Yamazaki Yuji , Yasutake Junichi , Kawata Takehisa , Hasegawa Hisashi , Urakawa Itaru , Fujita Toshiro , Wada Michihito , Yamashita Takeyoshi , Fukumoto Seiji , Shimada Takashi
Published: May 2009

X-linked hypophosphatemia (XLH), characterized by renal phosphate wasting, is the most common cause of vitamin D-resistant rickets. It has been postulated that some phosphaturic factor plays a causative role in XLH and its murine homolog, the Hyp mouse. Fibroblast growth factor 23 (FGF23) is a physiological phosphaturic factor; its circulatory level is known to be high in most patients with XLH and Hyp mice, suggesting its pathophysiological role in this disease. To test this hypothesis, we treated Hyp mice with anti-FGF23 antibodies to inhibit endogenous FGF23 action. A single injection of the antibodies corrected the hypophosphatemia and inappropriately normal serum 1,25-dihydroxyvitamin D. These effects were accompanied by increased expressions of type IIa sodium-phosphate cotransporter and 25-hydroxyvitamin-D-1α-hydroxylase and a suppressed expression of 24-hydroxylase in the kidney. Repeated injections during the growth period ameliorated the rachitic bone phenotypes typically observed in Hyp mice, such as impaired longitudinal elongation, defective mineralization, and abnormal cartilage development. Thus, these results indicate that excess actions of FGF23 underlie hypophosphatemic rickets in Hyp mice and suggest a novel therapeutic potential of the FGF23 antibodies for XLH.
MT1-MMP and Type II Collagen Specify Skeletal Stem Cells and Their Bone and Cartilage Progeny
Authors: Szabova Ludmila , Yamada Susan S. , Wimer Helen , Chrysovergis Kaliopi , Ingvarsen Signe , Behrendt Niels , Engelholm Lars H. , Holmbeck Kenn
Published: May 2009

Skeletal formation is dependent on timely recruitment of skeletal stem cells and their ensuing synthesis and remodeling of the major fibrillar collagens, type I collagen and type II collagen, in bone and cartilage tissues during development and postnatal growth. Loss of the major collagenolytic activity associated with the membrane-type 1 matrix metalloproteinase (MT1-MMP) results in disrupted skeletal development and growth in both cartilage and bone, where MT1-MMP is required for pericellular collagen dissolution. We show here that reconstitution of MT1-MMP activity in the type II collagen-expressing cells of the skeleton rescues not only diminished chondrocyte proliferation, but surprisingly, also results in amelioration of the severe skeletal dysplasia associated with MT1-MMP deficiency through enhanced bone formation. Consistent with this increased bone formation, type II collagen was identified in bone cells and skeletal stem/progenitor cells of wildtype mice. Moreover, bone marrow stromal cells isolated from mice expressing MT1-MMP under the control of the type II collagen promoter in an MT1-MMP-deficient background showed enhanced bone formation in vitro and in vivo compared with cells derived from nontransgenic MT1-MMP-deficient littermates. These observations show that type II collagen is not stringently confined to the chondrocyte but is expressed in skeletal stem/progenitor cells (able to regenerate bone, cartilage, myelosupportive stroma, marrow adipocytes) and in the chondrogenic and osteogenic lineage progeny where collagenolytic activity is a requisite for proper cell and tissue function.
FRAX and Risk of Vertebral Fractures: The Fracture Intervention Trial
Authors: Donaldson Meghan G. , Palermo Lisa , Schousboe John T. , Ensrud Kristine E. , Hochberg Marc C. , Cummings Steven R.
Published: May 2009

The validity of the WHO 10-yr probability of major osteoporotic fracture model (FRAX) for prediction of vertebral fracture has not been tested. We analyzed how well FRAX for major osteoporotic fractures, with and without femoral neck BMD (FN BMD), predicted the risk of vertebral fracture. We also compared the predictive validity of FRAX, FN BMD, and prevalent vertebral fracture detected by radiographs at baseline alone or in combination to predict future vertebral fracture. We analyzed data from the placebo groups of FIT (3.8-yr follow-up, n = 3221) with ORs and areas under receiver operating characteristics (ROC) curves (AUC). FRAX with and without FN BMD predicted incident radiographic vertebral fracture. The AUC was significantly greater for FRAX with FN BMD (AUC = 0.71) than FRAX without FN BMD (AUC = 0.68; p = 0.002). Prevalent vertebral fracture plus age and FN BMD (AUC = 0.76) predicted incident radiographic vertebral fracture as well as a combination of prevalent vertebral fracture and FRAX with FN BMD (AUC = 0.75; p = 0.76). However, baseline vertebral fracture status plus age and FN BMD (AUC = 0.76) predicted incident radiographic vertebral fracture significantly better than FRAX with FN BMD (AUC = 0.71; p = 0.0017). FRAX for major osteoporotic fractures (with and without FN BMD) predicts vertebral fracture. However, once FN BMD and age are known, the eight additional risk factors in FRAX do not significantly improve the prediction of vertebral fracture. A combination of baseline radiographic vertebral fracture, FN BMD, and age is the strongest predictor of future vertebral fracture.
Oxygen Tension Regulates the Expression of ANK (Progressive Ankylosis) in an HIF-1-Dependent Manner in Growth Plate Chondrocytes
Authors: Zaka Raihana , Dion Arnold S. , Kusnierz Anna , Bohensky Jolene , Srinivas Vickram , Freeman Theresa , Williams Charlene J.
Published: May 2009

The proximal promoter region of ANK, a gene that codes for a protein that regulates the transport of inorganic pyrophosphate, contains two hypoxia responsive elements (HREs); therefore, we studied the expression and function of ANK at different oxygen tensions. ATDC5 and N1511 clonal chondrocytic cells were cultured in either hypoxia (2% O2) or normoxia (21% O2). Transcript and protein levels of ANK were depressed in hypoxic conditions, as were levels of extracellular pyrophosphate (ePPi). To determine whether HIF-1 was involved in the oxemic response, Hif-1α knockdown cells were exposed to varying oxygen conditions and ANK expression was assessed. Knockdown of Hif-1α resulted in low levels of expression of ANK in hypoxia and normoxia. Chromatin immunoprecipitation (ChIP) assays explored the binding of Hif-1α to ANK HREs and showed that Hif-1α is able to bind to the HREs of ANK more avidly in normoxia than in hypoxia. Furthermore, functional studies of Hif-1α activity using luciferase reporter assays of wildtype and mutagenized HREs showed that only HRE-1 binds Hif-1α in normoxia. Expression of ANK in growth plate and articular cartilage was low in hypoxic regions of the tissues, and higher levels of ANK expression were observed in the synovium and meniscus in regions that have a normally higher oxygen tension. The data suggest that ANK expression and function in vitro and in vivo are repressed in hypoxic environments and that the effect is regulated by HIF-1.
A 5-Year Cohort Study of the Effects of High Protein Intake on Lean Mass and BMC in Elderly Postmenopausal Women
Authors: Meng Xingqiong , Zhu Kun , Devine Amanda , Kerr Deborah A. , Binns Colin W. , Prince Richard L.
Published: May 2009

Long-term effects of high dietary protein intake on muscle and bone structure in the elderly are not clear. The aim of this study was to investigate the relationship between baseline protein intake and lean mass and BMC 5 yr later in a cohort of elderly postmenopausal women. A total of 862 community-dwelling women 75 ± 3 yr of age provided baseline data including nutrient intake assessed by a food frequency questionnaire. At 5 yr, upper arm muscle area (UAMA) and body composition using DXA were measured. Baseline protein intake was 81 ± 28 g/d (1.2 ± 0.4 g/kg/d), contributing 19 ± 3% of total energy intake. There were positive correlations between baseline protein intake and whole body and appendicular bone-free lean mass and BMC (r = 0.14–0.18, p < 0.001) and UAMA (r = 0.08, p < 0.05). Compared with those in the lowest tertile of protein intake (<66 g/d), women in the top tertile (>87 g/d) had 5.4–6.0% higher whole body and appendicular lean mass and UAMA and 5.3–6.0% higher whole body and appendicular BMC. These effects remained after adjusting for potential confounders. However, the effect on BMC disappeared after further adjustment for lean mass. This study shows that high protein intake is associated with long-term beneficial effects on muscle mass and size and bone mass in elderly women. The protein effect on bone may be partly mediated by its effects on muscle.
Timing of Repeat BMD Measurements: Development of an Absolute Risk-Based Prognostic Model
Authors: Frost Steven A. , Nguyen Nguyen D. , Center Jacqueline R. , Eisman John A. , Nguyen Tuan V.
Published: May 2009

This study attempted to address the following questions: for an individual who is at present nonosteoporotic, given their current age and BMD level, what is the individual's risk of fracture and when is the ideal time to repeat a BMD measurement? Nonosteoporotic women (n = 1008) and men (n = 750) over the age of 60 in 1989 from the Dubbo Osteoporosis Epidemiology Study were monitored until one of the following outcomes occurred: (1) BMD reached “osteoporosis” level (i.e., T-scores ≤ −2.5) or (2) an incident fragility fracture. During the follow-up period (average, 7 yr), 346 women (34%) and 160 men (21%) developed osteoporosis or sustained a low-trauma fracture. The risk of osteoporosis or fracture increased with advancing age (women: RR/10 yr, 1.3; 95% CI, 1.1–1.6; men: RR/10 yr, 2.3; 95% CI, 1.7–2.9) and lower BMD levels (women: RR per −0.12 g/cm2, 3.2; 95% CI, 2.6–4.1; RR per −0.12 g/cm2, 2.6; 95% CI, 2.0–3.3). Using the predicted risk (of osteoporosis or fracture) of 10% as a cut-off level for repeating BMD measurement, the estimated time to reach the cut-off level varied from 1.5 (for an 80-yr-old woman with a T-score of −2.2) to 10.6 yr (for a 60-yr-old man with a T-score of 0). These results suggest that, based on an individual's current age and BMD T-score, it is possible to estimate the optimal time to repeat BMD testing for the individual. The prognostic model and approach presented in this study may help improve the individualization and management of osteoporosis.