bluuebunny/crossref_metadata_2025_split huggingface dataset:
Alendronate/Interleukin-1β Cotreatment Increases Interleukin-6 in Bone and UMR-106 Cells: Dose Dependence and Relationship to the Antiresorptive Effect of Alendronate
Authors: Sanders Jennifer L. , Tarjan Gabor , Foster Shirley A. , Stern Paula H. 
Published: April 2006

Abstract
Aminobisphosphonates inhibit bone resorption but have been shown to elicit acute-phase-like elevations in interleukin-6 (IL-6) in bone in vitro. The current studies were carried out to determine the relationship between the antiresorptive effects of the aminobisphosphonate alendronate and its effects on IL-6. Resorption was elicited in cultured 19-day fetal rat limb bones by 72 h treatment with interleukin-1β (IL-1β). Bone mass was quantitated at the end of the culture period to assess resorption. IL-6 was determined by bioassay (7TD1 cell proliferation). IL-1β (18 and 180 pM) stimulated bone resorption and increased IL-6. Alendronate (70 μM) inhibited the IL-1β–stimulated resorption. Alendronate alone did not affect IL-6 production by the bones. The IL-6 production from bones stimulated with 18 pM IL-1β was not significantly affected by alendronate, but the IL-6 production from bones stimulated with 180 pM IL-1β plus alendronate (21 and 70 μM) was higher than with IL-1β alone. Indomethacin (1 mM) inhibited the IL-6 increase elicited by 180 pM IL-1β and the enhanced IL-6 production elicited by cotreatment with IL-1β and alendronate. Since bone cultures contain multiple cell types, further experiments were carried out to determine whether alendronate could increase IL-1β–stimulated IL-6 production in an osteoblast cell line, UMR-106. Alendronate alone did not affect IL6 in UMR-106 cells. Alendronate (70 μM) in combination with IL-1β (180, 1.8, or 8 nM), or 7 μM alendronate, in combination with 8 nM IL-1β, significantly increased IL-6 in 48 h cell cultures. The results from the bone organ cultures show that alendronate can enhance IL-6 production elicited by higher concentrations of the cytokine IL-1β in bone, but that this effect on IL-6 does not prevent the inhibitory actions of alendronate on bone resorption. The results with the UMR106 cells indicate that one cellular site at which this enhancement of IL-6 production can occur is the osteoblast.
Vascular Pericytes Express Osteogenic Potential In Vitro and In Vivo
Authors: Doherty Mary Jo , Ashton Brian A. , Walsh Susan , Beresford Jon N. , Grant Michael E. , Canfield Ann E. 
Published: April 2006

Abstract
At postconfluence, cultured bovine pericytes isolated from retinal capillaries form three-dimensional nodule-like structures that mineralize. Using a combination of Northern and Southern blotting, in situ hybridization, and immunofluorescence we have demonstrated that this process is associated with the stage-specific expression of markers of primitive clonogenic marrow stromal cells (STRO-1) and markers of cells of the osteoblast lineage (bone sialoprotein, osteocalcin, osteonectin, and osteopontin). To demonstrate that the formation of nodules and the expression of these proteins were indicative of true osteogenic potential, vascular pericytes were also inoculated into diffusion chambers and implanted into athymic mice. When recovered from the host, chambers containing pericytes were found reproducibly to contain a tissue comprised of cartilage and bone, as well as soft fibrous connective tissue and cells resembling adipocytes. This is the first study to provide direct evidence of the osteogenic potential of microvascular pericytes in vivo. Our results are also consistent with the possibility that the pericyte population in situ serves as a reservoir of primitive precursor cells capable of giving rise to cells of multiple lineages including osteoblasts, chondrocytes, adipocytes, and fibroblasts.
Colony-Stimulating Factor-1 Stimulates the Fusion Process in Osteoclasts
Authors: Amano Hitoshi , Yamada Shoji , Felix Rolf 
Published: April 2006

Abstract
Colony-stimulating factor-1 (CSF-1), also called macrophage colony-stimulating factor, is required for growth, differentiation, activation, and survival of cells of the mononuclear phagocytic system. This cytokine has been shown to be essential for osteoclast development as well as for inducing both proliferation and differentiation of osteoclast progenitors. It also sustains survival of mature osteoclasts and stimulates spreading and migration of these cells. In the present in vitro study, the formation of large tartrate-resistant acid phosphatase (TRAP)-positive cells with a high number of nuclei was observed when osteoclasts isolated from rat long bones were incubated with CSF-1. These large cells, cultured on plastic, bind calcitonin and form F-actin along the edges of the cells. Fusion to such large TRAP-positive multinucleated cells in the presence of CSF-1 and the formation of pits were also observed on dentine slices. Quantitative data obtained from cultures on plastic demonstrated that the number of osteoclasts slightly increased in the course of 72 h in the presence of 250 pM CSF-1, whereas it decreased rapidly after 24 h in the absence of CSF-1, which confirms that this cytokine is required for the survival of osteoclasts. The number of nuclei per osteoclast was maximal after 16 h of incubation with CSF-1, namely twice the value found in the absence of CSF-1. The maximal effect of the cytokine on the fusion process was observed at a concentration of 250 pM. A calculation of the medians of the average frequency of nuclei distribution per osteoclast resulted in four nuclei per osteoclast in the absence and six in the presence of CSF-1. Genistein and herbimycin A, inhibitors of tyrosine kinases, inhibited the fusion induced by CSF-1. The data suggest that CSF-1 induces osteoclast fusion and that tyrosine kinase(s) are involved in this process. The fusion process may continue throughout the entire life of an osteoclast.
Regulation of Interleukin-6 Production by Prostaglandin E2 in Fetal Rat Osteoblasts: Role of Protein Kinase A Signaling Pathway
Authors: Millet Isabelle , Mccarthy Thomas L. , Vignery AgnÈS 
Published: April 2006

Abstract
Prostaglandin E2 (PGE2) is an abundant eicosanoid in bone that has been implicated in a number of pathological states associated with bone loss. Interleukin-6 (IL-6) is a cytokine that plays a critical role in bone remodeling and appears to act as a downstream effector of most bone-resorbing agents. In light of the evidence that PGE2 induces IL-6 in the bone environment, this study was designed to investigate whether PGE2 regulated IL-6 expression by osteoblasts. Here we demonstrate that PGE2 is a potent inducer of IL-6 production by fetal rat osteoblasts and synergizes with lipopolysaccharide to enhance IL-6. We show that PGE2 stimulates the activity of the IL-6 promoter in osteoblasts, suggesting that PGE2 controls IL-6 gene expression at least at the transcriptional level. Moreover, we show that PGE2-mediated IL-6 induction is prevented by the cAMP antagonist, Rp-cAMP, and the protein kinase A (PKA) inhibitors, KT5720 and H89. Thus, our data indicate that PGE2 involves the cAMP–PKA signaling pathway to regulate IL-6 gene expression in osteoblasts.
Generation of Mouse Osteoclastogenic Cell Lines Immortalized with SV40 Large T Antigen
Authors: Chen Wei , Li Yi-Ping 
Published: April 2006

Abstract
Progress in the field of osteoclast gene regulation has been hampered significantly by the lack of such cell lines. In this study, mouse osteoclast precursor cells were elicited in an osteoclast-inductive coculture system and immortalized using SV40 large T antigen. One of the osteoclast precursor cell lines (MOCP-5) forms 95% tartrate-resistant acid phosphatase positive (TRAP+) multinuclear osteoclast-like cells (OCLs) in the coculture system. The yield of TRAP+ OCLs was 4.5–7 × 104 cells per 10 cm2 dish. Expression of SV40 large T antigen was visualized in the nucleus of MOCP-5 cells and OCLs by immunohistochemistry. MOCP-5 cells were positive for MoMa-2 antigen and nonspecific esterase but negative for F4/80 antigen. OCLs derived from MOCP-5 cells were able to form extensive resorption bone pits on bone slices. The resorbing activity of the OCLs was comparable to that of authentic mouse osteoclasts. Pit formation was inhibited by salmon calcitonin (CT). Acid production by OCLs was demonstrated by vital staining with acridine orange. The OCLs expressed cathepsin K and CT receptors. MOCP-5 cells could be transfected by a construct that carries the β-galactosidase gene. Transfected MOCP-5 cells expressing β-galactosidase retain the ability to differentiate into OCLs, indicating a useful model for osteoclast gene regulation. To date, the MOCP-5 cell line has been maintained in continuous culture for 23 months and has maintained the capacity to differentiate into osteoclasts throughout this time. In summary, these data show that a stable immortalized osteoclast precursor cell line has been established and that the immortalization with SV40 large T oncogene does not prevent osteoclast precursor cell differentiation.
Bone Mineral Density and Its Change in Pre- and Perimenopausal White Women: The Michigan Bone Health Study
Authors: Sowers Maryfran , Crutchfield Mary , Bandekar Rajesh , Randolph John F. , Shapiro Brahm , Schork M. Anthony , Jannausch Mary 
Published: April 2006

Abstract
There is a need to better understand potential bone mineral density (BMD) loss during the menopausal transition since this period may include the initiation of interventions. The study purpose was to determine if there was BMD loss at the femoral neck, lumbar spine, or total body bone sites in a population-based study of women approaching or transitioning the midlife. The 583 enrollees were 25–45 years of age at the first of four annual measurements from 1992 through 1996. Bone mineral content and bone width were measured using dual-energy X-ray absorptiometry. Considering all enrollees collectively, there was a significant 3-year decline (1%) in BMD at the femoral neck over the 3-year period (p = 0.0076). There was no significant annual change in the lumbar spine (p = 0.11), and a significant annual increase in the total body BMD (p = 0.0003). Within subgroups and cross-sectionally, BMD values of the femoral neck were 5% lower in women classified as perimenopausal compared with premenopausal enrollees; BMD was 3% and 1% lower at the lumbar spine and total body sites, respectively. Longitudinally, among perimenopausal women, a double oophorectomy was associated with BMD loss in the spine (p = 0.0003), even though 75–85% of these women had a hormone replacement prescription at some time during the study period. In summary, the site with evidence of loss was the femoral neck, specifically among perimenopausal women. There was little evidence of substantial total body or lumbar spine BMD loss in premenopausal women with ovaries who maintained follicle-stimulating hormone levels &lt; 20 mIU/l in the early follicular period. Double oophorectomy, even with hormone replacement, was associated with bone loss.
Type of Physical Activity, Muscle Strength, and Pubertal Stage as Determinants of Bone Mineral Density and Bone Area in Adolescent Boys
Authors: Nordström Peter , Pettersson Ulrika , Lorentzon Ronny 
Published: April 2006

Abstract
The present study was conducted to evaluate the influence of different types of weight-bearing physical activity, muscle strength, and puberty on bone mineral density (BMD, g/cm2) and bone area in adolescent boys. Three different groups were investigated. The first group consisted of 12 adolescent badminton players (age 17.0 ± 0.8 years) training for 5.2 ± 1.9 h/week. The second group consisted of 28 ice hockey players (age 16.9 ± 0.3 years) training for 8.5 ± 2.2 h/week. The third group consisted of 24 controls (age 16.8 ± 0.3 years) training for 1.4 ± 1.4 h/week. The groups were matched for age, height, and pubertal stage. BMD, bone mineral content (BMC, g), and the bone area of the total body, lumbar spine, hip, femur and tibia diaphyses, distal femur, proximal tibia, and humerus were measured using dual-energy X-absorptiometry. When adjusting for the difference in body weight between the groups, the badminton players were found to have significantly higher BMD (p &lt; 0.05) of the trochanter and distal femur compared with the ice hockey players despite a significantly lower weekly average training. The badminton players had higher BMD compared with the control group at all weight-bearing BMD sites, except at the diaphyses of the femur and tibia and lumbar spine. The independent predictors of bone density were estimated by adjusting BMC for the bone area in a multivariate analysis among all subjects (n = 64). Accordingly, the bone density of all sites except the spine was significantly related to muscle strength and height, and the bone density of the total body, neck, trochanter, distal femur, and proximal tibia was significantly related to type of physical activity (β = 0.09–0.33, p &lt; 0.05). The bone area values at different sites were strongly related to muscle strength and height and less strongly related to the type of physical activity and pubertal stage. In conclusion, it seems that during late puberty in adolescent boys the type of weight-bearing physical activity is an important determinant of bone density, while the bone area is largely determined by parameters related to body size. The higher BMD at weight-bearing sites in badminton players compared with ice hockey players, despite significantly less average weekly training, indicates that physical activity including jumps in unusual directions has a great osteogenic potential.
A Dual-Label Immunofluorometric Assay for Human Osteocalcin
Authors: Ylikoski Alice , Hellman Jukka , Matikainen Terhi , Käkönen Sanna-Maria , Karp Matti , Väänänen H. Kalervo , Lövgren Timo , Pettersson Kim 
Published: April 2006

Abstract
Circulating human osteocalcin (hOC) has been shown to be comprised of two main forms: the intact 1–49 form and the proteolytic N-terminal midfragment (N-mid) spanning amino acid residues 1–43 or 1–44. We used three monoclonal antibodies (MAbs) raised against hOC and bovine osteocalcin in developing a dual-label assay for the simultaneous measurement of the proportions of the intact and N-mid forms in serum samples. The assay is based on time-resolved fluorescence utilizing differently labeled tracer MAbs. Biotinylated MAb 2H9 is used as a capture antibody for both the intact hOC and the N-mid. Tracer MAb 6F9 labeled with a Europium(III)-chelate binds to the N-mid and the intact hOC, whereas tracer MAb 3G8 labeled with a Terbium(III)-chelate binds to the intact hOC only. The simultaneous binding of the antibodies was tested by comparing full-length hOC purified from human bone and hOC shortened from the C terminus by four amino acid residues with carboxypeptidase Y. Serum hOC measurements with the dual-label assay were in agreement with the corresponding single-label assays (r = 0.96 for intact + N-mid assays and r = 0.81 for intact assays, n = 91). The lower correlation between the intact assays was attributable to proteolytic susceptibility of the intact form due to one additional freezing and thawing cycle in carrying out the dual-label assay. As measured with the dual-label assay, the levels (mean ± SD) of serum intact + N-mid OC were 6.2 ± 2.1 ng/ml in the premenopausal group (n = 44), 13.9 ± 4.9 ng/ml in the postmenopausal group without hormone replacement therapy (HRT; n = 13), and 7.5 ± 3.4 ng/ml in the postmenopausal group with HRT (n = 13). The levels of intact hOC in the same groups were 4.8 ± 1.4 ng/ml, 9.8 ± 2.9 ng/ml, and 5.3 ± 2.1 ng/ml, respectively. Whether the main forms of OC or their relative proportions in serum can be used for predicting bone diseases or for monitoring the progression and management of diseases awaits further investigations.
Extracellular Calcium (Ca2+o)-Sensing Receptor in a Mouse Monocyte-Macrophage Cell Line (J774): Potential Mediator of the Actions of Ca2+o on the Function of J774 Cells
Authors: Yamaguchi Toru , Kifor Olga , Chattopadhyay Naibedya , Bai Mei , Brown Edward M. 
Published: April 2006

Abstract
The calcium-sensing receptor (CaR) is a G protein-coupled receptor that plays key roles in extracellular calcium ion (Ca2+o) homeostasis in parathyroid gland and kidney. Macrophage-like mononuclear cells appear at sites of osteoclastic bone resorption during bone remodeling and may play a role in the “reversal” phase following osteoclastic resorption and preceding bone formation. Bone resorption produces substantial local increases in Ca2+o that could provide a signal for bone marrow mononuclear cells in the vicinity, leading us to investigate whether such mononuclear cells express the CaR. In this study, we used the mouse J774 cell line, which exhibits a pure monocyte-macrophage phenotype. Both immunocytochemistry and Western blot analysis, using polyclonal antisera specific for the CaR, detected CaR protein in J774 cells. The use of reverse transcriptase-polymerase chain reaction with CaR-specific primers, including a set of intron-spanning primers, followed by nucleotide sequencing of the amplified products, also identified CaR transcripts in J774 cells. Exposure of J774 cells to high Ca2+o (2.8 mM or more) or the polycationic CaR agonist, neomycin (100 μM), stimulated both chemotaxis and DNA synthesis in J774 cells. Therefore, taken together, our data strongly suggest that the monocyte-macrophage cell line, J774, possesses both CaR protein and mRNA very similar, if not identical, to those in parathyroid and kidney.
Cysteine Proteinases and Matrix Metalloproteinases Play Distinct Roles in the Subosteoclastic Resorption Zone
Authors: Everts Vincent , Delaissé Jean-Marie , Korper Wolf , Beertsen Wouter 
Published: April 2006

Abstract
Digestion of calvarial bone by osteoclasts depends on the activity of cysteine proteinases and matrix metalloproteinases (MMPs). It is unknown, however, whether these enzymes act simultaneously or in a certain (time) sequence. In the present study, this was investigated by culturing mouse calvarial bone explants for various time intervals in the presence or absence of selective low molecular weight inhibitors of cysteine proteinases (E-64, Z-Phe-Tyr(O-t-Bu)CHN2 or CA074[Me]) and MMPs (CI-1, CT1166, or RP59794). The explants were morphometrically analyzed at the electron microscopic level. All proteinase inhibitors induced large areas of nondigested demineralized bone matrix adjacent to the ruffled border of actively resorbing osteoclasts. The appearance of these areas proved to be time dependent. In the presence of the cysteine proteinase inhibitors, a maximal surface area of demineralized bone was seen between 4 and 8 h of culturing, whereas the metalloproteinase inhibitors had their maximal effect at a later time interval (between 16 and 24 h). Because different inhibitors of each of the two classes of proteolytic enzymes had the same effects, our data strongly suggest that cysteine proteinases attack the bone matrix prior to digestion by MMPs. In line with the view that a sequence may exist were differences in the amount of proteoglycans (shown with the selective dye cuprolinic blue) in the subosteoclastic demineralized areas induced by the inhibitors. In the presence of the cysteine proteinase inhibitor, relatively high levels of cuprolinic blue precipitates were found, whereas this was less following inhibition of metalloproteinases. These data suggested that cysteine proteinases are important for digestion of noncollagenous proteins. We propose the following sequence in the digestion of calvarial bone by osteoclasts: after attachment of the cell to the mineralized surface an area with a low pH is created which results in dissolution of the mineral, then cysteine proteinases, active at such a low pH, digest part of the bone matrix, and finally, when the pH has increased somewhat, MMPs exert their activity.
Bone Loss, Physical Activity, and Weight Change in Elderly Women: The Dubbo Osteoporosis Epidemiology Study
Authors: Nguyen T. V. , Sambrook P. N. , Eisman J. A. 
Published: April 2006

Abstract
The present study examined the effects of physical activity, weight, and weight change on femoral bone loss in relation to age in elderly women. Baseline and follow-up measurements at an average interval of 2.7 years of femoral neck bone mineral density (BMD) were reanalyzed for 827 women who were part of the Dubbo Osteoporosis Epidemiology Study. Physical activity was assessed based on hours per day spent in each of various activities according to its expected oxygen consumption. The rate of loss of BMD progressively increased with age, i.e., −0.6 ± 0.1, −1.1 ± 0.2, and −2.1 ± 0.6% per year (mean ± SEM) for the 60–69, 70–79, and ≥80 age groups, respectively (p &lt; 0.001). After adjustment for age, physically inactive women lost more (−1.4 ± 0.2% per year; p &lt; 0.001), compared with physically active women (−0.5 ± 0.3% per year; p = 0.15). Thinner women experienced more rapid bone loss, and women whose weight decreased (≥5%) over the study period lost more bone (−1.7 ± 0.4% per year) than those whose weight was stable (−0.8 ± 0.1% per year) or increased (+0.1 ± 0.3% per year; p &lt; 0.01, analysis of variance). Furthermore, women whose BMD was high (&gt;0.81 g/cm2) at baseline experienced greater loss (−1.1 ± 0.2%) compared with those in the middle tertile (1.0 ± 0.2%) or lowest tertile (−0.5 ± 0.3%). Independent predictors of rate of bone loss included age, baseline BMD, weight, weight change, and physical activity; collectively these factors accounted for 13% of total variance of bone loss by multiple regression analysis. It is concluded that a physically active lifestyle and stable weight in the later decades of life may retard proximal femur bone loss and thus contribute to reduction of fracture risk.
Falls Among Community-Dwelling Elderly in Japan
Authors: Aoyagi Kiyoshi , Ross Philip D. , Davis James W. , Wasnich Richard D. , Hayashi Takuo , Takemoto Tai-Ichiro 
Published: April 2006

Abstract
Japanese have a lower incidence of hip fracture than Caucasians despite having lower bone mass. Hip fractures usually occur after a fall, and differing incidence rates of falls might explain the observed differences in hip fracture rates. To explore this hypothesis, we studied falls and related conditions among 1534 (624 men, 910 women) community-dwelling people aged 65 years and over in Japan and compared the prevalence of falls to Japanese-Americans living in Hawaii and to published studies of Caucasians. In Japan, 9% of the men and 19% of the women reported one or more falls during the past year. The prevalence of falls increased with age in both genders and was greater among women compared with men. In logistic regression models, having musculoskeletal disease, physical disability or limited activity increased the risk of falls by two to four times in both genders. Most fallers (92%) reported fear of future falls, and about one third of fallers reported that they went out less often as a result of their falls. Compared with native Japanese, the age-standardized prevalence of falls among Japanese-Americans was similar but about twice as high for Caucasians, which may explain the lower hip fracture risk of Japanese.