bluuebunny/crossref_metadata_2025_split huggingface dataset:
Bone resorption by isolated osteoclasts in living versus devitalized bone: Differences in mode and extent and the effects of human recombinant tissue inhibitor of metalloproteinases
Authors: Shimizu Hideo , Sakamoto Masako , Sakamoto Seizaburo 
Published: February 2010

Abstract
The incubation of isolated osteoclasts with devitalized bone has become a widely used method for the recent study of bone resorption. Although the studies employing this method have definitively demonstrated that isolated osteoclasts have an avid capacity to resorb devitalized bone, the resorption in this model appears to be different from that of living bone as observed in vivo and in organ culture studies.
To evaluate how the resorption of living bone is different from that of devitalized bone, we have extended this bone resorption model using isolated osteoclasts by including both devitalized and living bone substrates. Living bone substrates were freshly prepared from calvaria of 8- to 12-month-old mice. Periosteum, cellular components, and osteoid were completely scraped off to leave a rigid, smooth, mineral-exposed surface for the isolated osteoclasts to act upon. Some of the bone pieces were devitalized by repeated freezing and thawing. Living and devitalized bones were cultured with isolated rabbit osteoclasts for 60 h with or without recombinant human tissue inhibitor of metalloproteinases (100 μg/ml). The extent of bone resorption was assessed by measuring both the area and the depth of resorption pits.
Comparing the areas of the resorption pits showed significantly more resorption in living bone than in devitalized bone (27% of that of living bone). Recombinant human TIMP reduced the resorption of living bone by 73% but did not, however, inhibit the resorption of devitalized bone. Similarly, resorption pits formed on the living bones were significantly deeper (on the average, 12.4 μm) than those formed on the devitalized bones (on the average, 4.3 μm). The average depth of the resorption pits on living bone was significantly reduced by the presence of the inhibitor, whereas there was no difference between the control and inhibitor-treated devitalized bones. These results suggest that the mechanisms underlying the resorption of living bone and that of devitalized bone are not the same and that the resorption of living bone is aided by osteocytes.
Bone density changes in osteoporosis-prone women exposed to pulsed electromagnetic fields (PEMFs)
Authors: Tabrah Frank , Hoffmeier Mary , Gilbert Fred , Batkin Stanley , Bassett C. A. L. 
Published: February 2010

Abstract
To determine the effect of a 72 Hz pulsating electromagnetic field (PEMF) on bone density of the radii of osteoporosis-prone women, the nondominant forearms of 20 subjects were exposed to PEMF 10 h daily for a period of 12 weeks. Bone density before, during, and after the exposure period was determined by use of a Norland-Cameron bone mineral analyzer. Bone mineral densities of the treated radii measured by single-photon densitometry increased significantly in the immediate area of the field during the exposure period and decreased during the following 36 weeks. A similar but weaker response occurred in the opposite arm, suggesting a “cross-talk” effect on the nontreated radii, from either possible arm proximity during sleep or very weak general field effects. The data suggest that properly applied PEMFs, if scaled for whole-body use, may have clinical application in the prevention and treatment of osteoporosis.
Second messengers in thrombin-stimulated bone resorption
Authors: Dr. Stern Paula H. , Stathopoulos Victoria M. , Shankar Geetha , Fenton John W. 
Published: February 2010

Abstract
Characterized human thrombins and two commercial bovine thrombin preparations were examined for their effects on bone resorption and on the cyclic AMP and phosphoinositide second messenger systems in bone. Human α- and γ-thrombins, as well as both bovine thrombin preparations, stimulated bone resorption in vitro, whereas catalytically inactivated human diisopropylfluorophosphate (DIP)-α-thrombin did not significantly stimulate resorption. Human α-thrombin and a commercial bovine thrombin preparation increased cyclic AMP production in fetal rat limb bones, but another bovine commercial thrombin preparation and γ-thrombin did not. Except for DIP-α-thrombin, all thrombins increased production of inositol phosphates in fetal rat limb bones at concentrations that stimulated resorption. In time course studies, bovine thrombin increased label in inositol trisphosphate at 30 s, with decreasing effects at later times. Inositol monophosphate increased progressively over 30 min. Our results are consistent with thrombin-stimulated bone resorption being mediated at least partially through the inositol phosphate pathway.
Bone mineral content in hypothyroid male patients with hormone replacement: A 3-year study
Authors: Toh Sang H. , Brown Paul H. 
Published: February 2010

Abstract
Several studies have reported that short-term thyroid replacement to the euthyroid state in hypothyroid patients produces loss of both cortical and trabecular bone. However, long-term follow-up studies on this subject have not been reported. We conducted a 3 year follow-up study on 35 white male patients, including 24 patients (groups 1 and 2) with hypothyroidism receiving thyroid hormone replacement to the euthyroid state and 11 patients (groups 3 and 4) with Graves' disease. The bone mineral content of the distal radius was determined by single-photon absorption techniques with an iodine 125 source. It was found that there was no statistically significant difference in bone mineral content by year for any group, indicating no evidence of significant loss of cortical bone mineral by thyroid hormone replacement to the euthyroid state in hypothyroid patients.
Identification of plasminogen activator in osteoclasts
Authors: Grills Brian L. , Allan Elizabeth H. , Yumita Shigeru , Martin T. John , Gallagher James A. 
Published: February 2010

Abstract
Plasminogen activator (PA) was located in newborn rat osteoclasts using a single-cell assay. Immunohistochemistry using biotin-streptavidin-peroxidase indicated the presence of both tissue-type plasminogen activator (tPA) and urokinase (uPA) within the cytoplasm of osteoclasts isolated from newborn rat long bones. Electron microscopic immunohistochemistry using the biotin-streptavidin-colloidal gold system on L.R. Gold thin resin sections of undecalcified, newborn rat tibial metaphyseal trabecular bone identified these proteases in the lysosomal network of osteoclasts. uPA was also localized in marrow macrophage lysosomes, but tPA was not detected in these cells. The localization of these enzymes within osteoclasts may imply their involvement in bone resorption.
Are vitamin D receptor polymorphisms associated with bone mineral density? A meta-analysis
Authors: Cooper Glinda S. , Umbach David M. 
Published: February 2010

AbstractVitamin D receptor (VDR) polymorphisms have been strongly associated with bone mineral density (BMD) in some studies but not in others. We used a meta-analytic approach to assess quantitatively the association between VDR and BMD and to examine the influence of specific study characteristics (e.g., skeletal site, mean age of subjects, menopausal status) on the reported results. Sixteen papers published in peer-reviewed journals through July 1996 were included. We calculated the mean difference, percent difference, and effect size (mean difference divided by standard deviation), comparing BMD between homozygous genotypes. At the hip, BMD in the BB genotype was lower than in the bb genotype (mean difference, −0.02 g/cm2; percent difference, −2.4%; and effect size −0.18; p = 0.032). At the spine, the mean difference was −0.03 g/cm2; percent difference, −2.5%; and effect size, −0.19; p = 0.062. At the distal radius, the VDR effect was estimated as the mean difference, −0.01 g/cm2; percent difference, −1.7% and effect size, −0.16; p = 0.078. The spine measurements exhibited the greatest between- and within-study variability. The difference in hip BMD between genotypes was larger (i.e., a more negative number) among the younger women and seemed to decrease with increasing age. However, statistical evidence for this trend was weak (p = 0.06). Data from the spine and the radius showed no evidence of a comparable interaction of the VDR effect with age. When we omitted data from the first report of an association between VDR polymorphisms and BMD, our analyses gave similar results, although the overall effect estimates were smaller. In the combined data from 29 study groups, the BB genotype frequency was 17.2, 4.9, and 2.3% in studies of whites, blacks, and Asians, respectively. VDR polymorphisms represent one genetic factor affecting BMD, but further research into the mechanisms, clinical significance, and its relation between other genetic and environmental factors is needed.
Expression and phorbol ester–induced down-regulation of protein kinase C isozymes in osteoblasts
Authors: Sanders Jennifer L. , Stern Paula H. 
Published: February 2010

Abstract
The protein kinase C (PKC) enzyme family consists of at least 11 isozymes in three classes, with characteristic tissue distributions. Phorbol esters activate and ultimately down-regulate phorbol-sensitive isozymes. PKC is a signal transducer in bone, and phorbol esters influence bone resorption. Little is known about specific PKC isozymes in this tissue, however. We describe here the expression and phorbol ester-induced down-regulation of PKC isozymes in osteoblasts. Normal mouse osteoblasts and seven osteoblastic cell lines (rat UMR-106, ROS 17/2.8, ROS 24/1, and human MG-63, G-292, SaOS-2, HOS-TE85) were screened for isozyme expression by Western immunoblotting using isozyme-specific anti-PKC antibodies. The conventional α and βI, isozymes, but not γ, were present in each of the osteoblasts examined; PKC-βII was detectable in all but the ROS 24/1 line. PKC-ε was expressed in all osteoblasts screened, but other novel PKCs, δ, η, and θ, were detectable only in select lines. The atypical ζ and ι/λ PKCs were in all osteoblasts examined. To determine the sensitivity of the isozymes to prolonged phorbol ester treatment, normal osteoblasts and the UMR-106 cell line were treated with vehicle or 1 μM phorbol 12, 13-dibutyrate (PDB) for 1, 3, 6, 12, 24, or 48 h, and Western blot analysis was performed. Normal and UMR-106 cells showed similar phorbol sensitivities; conventional (α, βI) and novel (δ, ε, η) isozymes were down-regulated by prolonged phorbol treatment but atypical isozymes were not. Down-regulation of all sensitive PKCs was detectable within 6 h of phorbol treatment; the novel δ and ε isozymes, however, showed more rapid and dramatic down-regulation than conventional isozymes. The observed down-regulation was dose-dependent (0.3–3 μM) and specific; 48 h treatment with the inactive phorbol, 4α-phorbol 12,13-didecanoate (4α-PDD), failed to down-regulate PDB-sensitive isozymes. The phorbol-induced down-regulation was also reversible; 24 h after withdrawing PDB, all phorbol-sensitive isozymes, except PKC-η, had recovered at least partially. These studies, the first to characterize thoroughly PKC isozyme expression in osteoblastic cells from several species, demonstrate that osteoblasts have a characteristic PKC isozyme profile, including both phorbol ester–sensitive and –insensitive isozymes. The time course of down-regulation and the presence of phorbol-insensitive PKCs must be considered in interpreting the effects of phorbol esters on bone remodeling.
Osteogenic actions of phenytoin in human bone cells are mediated in part by TGF-β1
Authors: Nakade Osamu , Baylink David J. , Lau K.-H. William 
Published: February 2010

Abstract
We have recently demonstrated that phenytoin, a widely used therapeutic agent for seizure disorders, has osteogenic effects in rats and in humans in vivo, and in human bone cells in vitro. The goal of the present study was to determine the mechanism of the osteogenic action of phenytoin in normal human mandible-derived bone cells. Because many osteogenic agents increased bone cell proliferation through mediation by growth factors, we tested the hypothesis that the osteogenic effects of phenytoin involved the release of a growth factor by measuring the mRNA level of several bone cell growth factors and insulin-like growth factor (IGF) binding proteins with Northern blots using specific cDNA probes. Treatment with 5–50 μM phenytoin reproducibly and markedly increased (up to 6-fold, p &lt; 0.001) the mRNA of transforming growth factor (TGF)-β1, but not that of other growth factors (i.e., IGF-II, platelet-derived growth factor-A [PDGF-A], PDGF-B, and TGF-β2) and IGF binding proteins (i.e., IGFBP-3, −4, and −5). The stimulation was dose dependent, with an optimal dose of 10–50 μM. Maximal increase was seen after 1 h of phenytoin treatment. The release of biologically active TGF-β activity in conditioned media was measured with the mink lung cell proliferation inhibition assay. Twenty-four hours of phenytoin treatment significantly increased the production of biologically active TGF-β (2-fold, p &lt; 0.05) with the optimal dose between 5–50 μM. Comparisons between the in vitro osteogenic effects of phenytoin and those of TGF-β1 reveal that these two agents at their respective optimal doses had similar maximal stimulatory effects on [3H]thymidine incorporation, alkaline phosphatase (ALP)-specific activity, and type Iα-2 collagen mRNA expression in human bone cells. The stimulatory effects of phenytoin on [3H]thymidine incorporation and ALP-specific activity were completely blocked by a neutralizing anti-TGF-β antibody. In conclusion, these findings demonstrate for the first time that at least some of the osteogenic actions of phenytoin in human bone cells could be in part mediated by TGF-β1.
RS-66271, a C-terminally substituted analog of human parathyroid hormone-related protein (1–34), increases trabecular and cortical bone in ovariectomized, osteopenic rats
Authors: Vickery Brian H. , Avnur Zafrira , Cheng Yvonne , Chiou San-San , Leaffer David , Caulfield John P. , Ho Theresa , Krstenansky John L. , Kimmel Donald B. 
Published: February 2010

Abstract
It was predicted from the amino acid sequence of the bone anabolic peptides, parathyroid hormone (PTH) (1–34) and PTH related protein (PTHrP) (1–34), that the C-terminal amino acids form an amphipathic α-helix. Therefore, we substituted a model amphipathic α-helical peptide (MAP) sequence in the C-terminal region of hPTHrP(1–34), obtaining RS-66271 ([MAP1–10]]22–31 hPTHrP(1–34)-NH2). The anabolic activities of RS-66271 and hPTHrP(1–34) were evaluated in 3-month-old, ovariectomized (OVX) osteopenic rats. Subcutaneous injection of hPTHrP(1–34) at 80 μg/kg/day partially reversed estrogen depletion trabecular bone loss but was ineffective in the cortex. In contrast, RS-66271 dose-relatedly reversed loss at both sites and, at 80 μg/kg/day, returned both trabecular and cortical bone calcium to the level of sham-operated controls. Histomorphometric analysis showed significantly elevated bone formation rates over vehicle-treated OVX in both trabecular and cortical tibial bone following treatment with RS-66271. Electron microscopy showed an increase in the relative surface area of vertebral trabeculae covered by osteoblasts in animals treated with RS-66271. These studies demonstrate that the C-terminal amino acids of hPTHrP(1–34) can be replaced by a model amphipathic helix and that the new chemical entity has greater anabolic activity than the parent peptide. The results suggest that RS-66271 may be a candidate molecule for the treatment of human osteoporosis.
The renal clearance of free and conjugated pyridinium cross-links of collagen
Authors: Colwell A. , Eastell R. 
Published: February 2010

Abstract
We developed a sensitive reversed-phase high performance liquid chromatography (HPLC) assay to measure free and total Pyridinoline (Pyr) and Deoxypyridinoline (Dpyr) in serum. The method was used to measure total serum levels in seven premenopausal women (ages 52.2 + 2.4 years) and to investigate the renal clearance of free and conjugated Pyr and Dpyr in two groups of children (group 1: 13 girls, ages 11–13 years; group 2: 18 older children [2 male, 16 female], ages 13–18 years). Blood and 24-h urine samples were collected from the younger group to measure the renal clearance, and blood and 2-h morning urine samples from the older group were collected to investigate the fractional clearance. Total Pyr and Dpyr in the premenopausal women was 4.08 + 0.91 and 1.18 + 0.39 nmol/l, respectively. Free and total Pyr and Dpyr in serum and urine was elevated in both groups of children. The free serum levels were 16 and 18% in young and older children, respectively, compared with 40 and 46% in the urine. The percentage of free Dpyr in serum decreased with total urinary Pyr excretion (r = −0.56, p &lt; 0.005, n = 31). The renal clearance of the free cross-link fraction in both groups was 4-fold higher than the conjugated fraction. The fractional clearance of the free fraction was greater than 1 (p &lt; 0.001) and the conjugated fraction less than 1 (p &lt; 0.001). The fractional excretion of free Dpyr increased with total urinary Pyr excretion (r = 0.66, p &lt; 0.005, n = 13). We conclude that HPLC can be used to measure free and total Pyr and Dpyr in serum and that some free Pyr and Dpyr excreted in urine is produced by the kidney.
Inhibition of HIV‐1 infection by a unique short hairpin RNA to chemokine receptor 5 delivered into macrophages through hematopoietic progenitor cell transduction
Authors: Liang Min , Kamata Masakazu , Chen Kevin N. , Pariente Nonia , An Dong Sung , Chen Irvin S. Y. 
Published: February 2010

AbstractBackgroundWe recently expressed a potent and noncytotoxic short hairpin (sh)RNA directed against chemokine (c‐c motif) receptor 5 (CCR5) using lentiviral mediated transduction of CD34+ hematopoietic progenitor cells (HPCs) and demonstrated the stable reduction of CCR5 expression in T‐lymphocytes.MethodsIn the present study, we further assessed the activity of the shRNA through HPC transduction and differentiation into macrophages derived from fetal liver CD34+ (FL‐CD34+) HPCs. Transduced lentiviral vector encoding the human CCR5 shRNA was stably maintained in FL‐CD34+ cells and in the terminally differentiated macrophages using macrophage colony‐stimulating factor, granulocyte macrophage colony‐stimulating factor, interleukin‐3 and stem cell factor.ResultsQuantitative real‐time polymerase chain reaction for CCR5 mRNA indicated over 90% reduction of CCR5 mRNA levels in CCR5 shRNA‐transduced population. The cells with knockdown of CCR5 expression acquired resistance to R5 tropic HIV‐1 NFN‐SX strain. We also developed a novel approach utilizing a mCherry‐CCR5 chimeric reporter to assess the effectiveness of CCR5 target down‐regulation in macrophages directly. Both the shRNA and the reporter were maintained throughout HPC differentiation to macrophages without apparent cytotoxicity.ConclusionsThe present study demonstrates a novel method to simply and directly assess the function of small interfering RNA and the effective inhibition of HIV‐1 infection by a potential potent shRNA to CCR5 delivered into macrophages derived from HPCs. Copyright © 2010 John Wiley & Sons, Ltd.
Neoadjuvant therapy for pancreatic cancer: A current review
Authors: Abbott Daniel E. , Baker Marshall S. , Talamonti Mark S. 
Published: February 2010

AbstractThe optimal therapy for pancreatic cancer continues to evolve. Neoadjuvant chemoradiation is a key component of current treatment regimens, and evaluation of previous treatment options will help guide future trials. Here the authors present a review of the current literature with discussion of future directions. J. Surg. Oncol. 2010; 101:315–320. © 2010 Wiley‐Liss, Inc.
Membrane protected conductive polymer as micro‐SPE device for the determination of triazine herbicides in aquatic media
Authors: Bagheri Habib , Khalilian Faezeh , Naderi Mehrnoush , Babanezhad Esmaeil 
Published: February 2010

AbstractA micro‐SPE technique was developed by fabricating a rather small package including a polypropylene membrane shield containing the appropriate sorbent. The package was used for the extraction of some triazine herbicides from aqueous samples. Solvent desorption was subsequently performed in a microvial and an aliquot of extractant was injected into GC‐MS. Various sorbents including aniline‐ortho‐phenylene diamine copolymer, newly synthesized, polypyrrole, multiwall carbon nanotube, C18 and charcoal were examined as extracting media. Among them, conductive polymers exhibited better performance. Influential parameters including extraction and desorption time, desorption solvent and the ionic strength were optimized. The developed method proved to be rather convenient and offers sufficient sensitivity and good reproducibility. The detection limits of the method under optimized conditions were in the range of 0.01–0.04 ng/mL. The RSDs at a concentration level of 0.1 ng/mL were obtained between 4.5 and 9.3% (n=5). The calibration curves of analytes showed linearity in the range of 0.05–10 ng/mL. The developed method was successfully applied to the extraction of selected triazines from real water samples. The whole procedure showed to be conveniently applicable and quite easy to manipulate.
Enrichment and isolation of barbigerone from Millettia pachycarpa Benth. using high‐speed counter‐current chromatography and preparative HPLC
Authors: Ye Haoyu , Zhong Shijie , Li Yanfang , Tang Minghai , Peng Aihua , Hu Jia , Shi Jie , He Shicao , Wu Wenshuang , Chen Lijuan 
Published: February 2010

AbstractEnrichment of the anti‐tumor compound barbigerone along with a rotenoid derivative from Millettia pachycarpa Benth. was performed by a two‐step high‐speed counter‐current chromatography (HSCCC) separation process. In the first step, 155.8 mg of target fraction (Fra6) was obtained from 400 mg ethyl acetate extract of M. pachycarpa Benth. with an increase in barbigerone from 5.1 to 13% via HSCCC using a solvent system of n‐hexane–ethyl acetate–methanol–water (5:4:5:3, v/v) under normal phase head to tail elution. HSCCC was repeated to eliminate the major contaminant in this initial fraction 6. After a separation time of 65 min, 22.1 mg barbigerone of 87.7% purity was obtained from Fra6 with the ternary solvent system of n‐hexane–methanol–water (2:2:1, v/v) under normal phase elution. Finally, preparative HPLC was employed for the further isolation of barbigerone and the rotenoid derivative. The structures were confirmed by ESI‐MS, 1H NMR and 13C NMR.
Investigation of commercial sorbents for the analysis of opioid peptides in human plasma by on‐line SPE‐CE
Authors: Benavente Fernando , Medina‐Casanellas Silvia , Barbosa José , Sanz‐Nebot Victoria 
Published: February 2010

AbstractIn this study, we investigated the performance of several commercial sorbents (Sep‐pack® C18, tC18, C8 and tC2, Oasis® HLB, Isolute® ENV+, Strata™‐X and Oasis® MCX) for the determination of opioid peptides by solid‐phase extraction coupled on‐line to capillary electrophoresis (SPE‐CE). First, standard solutions were analyzed in order to achieve the lowest LOD and the best electrophoretic separations using UV detection. The best results were obtained using C18, C8 and tC2 sorbents, which were examined for the analysis of spiked human plasma samples. A double‐step sample clean‐up pretreatment, which consisted of precipitation with acetonitrile and filtration, was needed to prevent saturation of the on‐line SPE microcartridge. The filtration step was critical to obtain optimum analyte recovery and to clean up the sample matrix. A range of centrifugal filters and filtration conditions were tested and the recoveries of the sample pretreatment were evaluated by CE‐ESI‐MS. The LODs attained through SPE‐CE‐UV were approximately ten‐fold better with C18 than with C8 and tC2. The 0.1 μg/mL LODs achieved by C18‐SPE‐CE‐UV were further improved until we could detect 1 ng/mL concentrations of opioid peptides in plasma samples by C18‐SPE‐CE‐ESI‐MS, due to the outstanding selectivity of the MS detection.