bluuebunny/crossref_metadata_2025_split huggingface dataset:
Secretion of osteocalcin and its propeptide from human osteoblastic cells: Dissociation of the secretory patterns of osteocalcin and its propeptide
Authors: Hosoda Kenji , Kanzaki Susumu , Eguchi Hiroshi , Kiyoki Mamoru , Yamaji Teizo , Koshihara Yasuko , Shiraki Masataka , Seino Yoshiki 
Published: February 2010

Abstract
Specific immunoassay systems for intact human osteocalcin (I-OC) and its 26-residue propeptide have been newly developed to assess their usefulness as biochemical markers of bone metabolism. Using human cultured osteoblastic periosteal cells, we monitored 24 h secretion of these molecules from the osteoblastic cells and also examined the deposition of Ca, P, and I-OC on the extracellular matrix. At day 5, both I-OC and its propeptide were secreted by osteoblastic cells in a concentration-dependent manner by treatment with 1,25-(OH)2D3. This propeptide was not detected in the serum of adult subjects but was detected in the serum of normal children, which confirmed this in vitro result of propeptide secretion. The secretion of I-OC into medium transiently decreased at day 11, when the rapid accumulation of I-OC, Ca, and P, namely mineralization, was observed on the extracellular matrix of osteoblastic cells, although secretion of the propeptide constantly increased throughout the culture period. Therefore, the ratio of the amount of propeptide to I-OC in the supernatant markedly increased when mineralization started. These data demonstrate the superior specificity of propeptide as a marker of osteoblastic function in vitro compared with I-OC and that monitoring the changes in propeptide to I-OC ratios in the culture supernatant may be useful for predicting the timing of mineralization on the extracellular matrix of osteoblastic cells.
Effects of weight and body mass index on bone mineral density in men and women: The framingham study
Authors: Felson David T. , Zhang Yuqing , Hannan Marian T. , Anderson Jennifer J. 
Published: February 2010

Abstract
We evaluated the association of weight and bone mass in elderly male and female subjects of the Framingham osteoporosis study, a subset of the Framingham study cohort. By examining the differences in the correlations of weight with bone mass among men and women in weight-bearing and non-weight-bearing sites and weight change since early adulthood, we attempted to understand different ways in which weight or body mass index affects bone mass. During biennial examination 20 of the Framingham cohort (1988–1989), 693 women and 439 men (mean age 76 years) had proximal femur bone mineral density assessed by dual-photon absorptiometry (DPA) and radius bone mass assessed by single-photon absorptiometry. The majority of these subjects also had spine measurements by DPA. Subjects had been weighed repeatedly over 40 years. After adjusting for other factors affecting bone density, we found that both recent weight and body mass index explained a substantial proportion of the variance in bone mineral density for all sites in women (8.9–19.8% of total variance, all p &lt; 0.01) and for only weight-bearing sites (femur and spine) in men (2.8–6.9% of total variance, all p &lt; 0.01). For bone mineral density at the proximal radius, weight and body mass index accounted for &lt; 1% of variance in men (p NS). Weight change since biennial examination 1 (1948–1951) was the strongest explanatory factor for bone mineral density among women at all sites, but weight change did not affect radius bone mineral density in men. The effect of weight and of weight change on bone mineral density was in general much less in men than in women. Our results suggest that the strong effect of weight on bone mineral density is due to load on weight-bearing bones in both sexes. The sex difference is unexplained but may be due to adipose tissue production of estrogen in women after menopause.
Interleukin-1 receptor antagonist inhibits the hypercalcemia mediated by interleukin-1
Authors: Guise Theresa A. , Garrett I. Ross , Bonewald Lynda F. , Mundy Gregory R. 
Published: February 2010

Abstract
Recently, the effects of interleukin-1 (IL-1) on bone resorption in organ culture have been shown to be inhibited by an interleukin-1 receptor antagonist (IL-1RA), a novel monocyte cytokine in the IL-1 family. IL-1RA, which binds to IL-1 receptors and inhibits many of the effects of IL-1α and β, has been purified, cloned, and expressed. We used IL-1RA to investigate its effects on calcium homeostasis in vivo. After confirming that IL-1RA completely inhibited the effects of IL-1 on bone resorption in organ cultures, we tested the effects of IL-1RA on hypercalcemia mediated by IL-1 in normal mice and found that prolonged hypercalcemia provoked by IL-1 was completely inhibited by IL-1RA. The initial transient decrease in blood ionized calcium observed following an injection of IL-1 was also abrogated. IL-1RA had no effect alone on blood ionized calcium or on hypercalcemia mediated by parathyroid hormone (PTH) or PTH-related protein (PTHrP). These data suggest that antagonists to the IL-1 receptor may provide a useful therapeutic approach to osteoclastic bone resorption and hypercalcemia that is IL-1 dependent.
An uncoupling agent containing strontium prevents bone loss by depressing bone resorption and maintaining bone formation in estrogen-deficient rats
Authors: Marie Pierre J. , Hott Monique , Modrowski Dominique , De Pollak Cinderella , Guillemain Joel , Deloffre Pascale , Tsouderos Yannis 
Published: February 2010

Abstract
Trabecular bone loss in estrogen deficiency is associated with enhanced bone resorption with a smaller increase in bone formation. We previously reported that low doses of strontium can increase trabecular bone volume in rodents by affecting bone resorption and formation. In this study we determined the effect of a new divalent strontium salt (S12911) on bone loss induced by E2 deficiency. Sprague-Dawley female rats (230 g, n = 15–25 per group) were sham operated or ovariectomized (OVX) and treated with 17β-estradiol (E2, 10 μg/kg/day, sc) or S12911 by gavage at the dose of 77, 154, or 308 mg/kg/day or the vehicle. Treatment for 60 days with S12911 resulted in a dose-dependent increase in plasma, urine, and bone strontium concentrations without any deleterious effect on total or skeletal growth. OVX rats were osteopenic compared to sham rats as shown by decreased femoral dry bone weight and mineral content measured on bone ash and by DXA. Treatment of OVX rats with S12911 prevented bone loss as bone ash and bone mineral content were restored to the values in sham rats. Trabecular bone volume measured by histomorphometry on the tibial metaphysis was decreased by 46% in OVX rats and was corrected by E2. Treatment of OVX rats with S12911 increased the trabecular bone volume by 30–36%. Histomorphometric indices of bone resorption (osteoclast surface and number) were increased in OVX rats and were reduced by S12911 to the levels in sham rats. In contrast to this inhibitory effect on bone resorption, the osteoid surface, osteoblast surface, mineral apposition rate, and bone formation rate were as high in OVX rats treated with S12911 as in untreated OVX rats. In addition, plasma osteocalcin (OC) and alkaline phosphatase (ALP) levels remained elevated or were further increased in OVX rats treated with S12911. In contrast, treatment with E2 reduced both bone resorption and formation and plasma ALP and OC to the levels in sham rats. The data indicate that the divalent strontium salt S12911 is acting as an uncoupling agent that can prevent the femoral osteopenia and partially prevent the trabecular bone loss in E2-deficient rats by inhibiting bone resorption without reducing bone formation.
Production of leukemia inhibitory factor mRNA and protein by malignant and immortalized bone cells
Authors: Marušić Ana , Kalinowski Judith F. , Jastrzebski Sandra , Lorenzo Joseph A. 
Published: February 2010

Abstract
Leukemia inhibitory factor (LIF) is a recently characterized glycoprotein with complex biologic activities on bone cells. We tested various rodent and human immortalized and malignant bone cell lines and primary osteoblast-enriched cell cultures from fetal rat calvarial digests for expression of LIF mRNA and LIF protein. Both human and rodent immortalized and malignant cells expressed a single 4.4 kb mRNA transcript that hybridized to a human LIF cDNA probe in Northern blots. LIF mRNA was undetectable in unstimulated rodent osteoblast-like cells lines MC3T3-E1 and Pyla. However, treatment with LPS (10 μg/ml), TGF-β (1 ng/ml), TNF-α (100 ng/ml) or inhibitors of protein synthesis (cycloheximide, emetine, puromycin, and anisomycin) induced the expression of LIF message in these cells. In contrast, primary osteoblast-enriched cells did not express LIF mRNA in Northern blot assays either constitutively or after treatment with TNF-α or cycloheximide. The human osteosarcoma cells lines U-2 OS and Saos-2 constitutively expressed LIF mRNA and did not respond to LPS treatment. However, phorbol myristate acetate (PMA), an activator of protein kinase C, was a potent stimulator of LIF message in Saos-2 but not U-2 OS cells. The effects of PMA (0.5 ng/ml) on LIF mRNA in Saos-2 cells were detectable at 1 h and maximal at 6 h. TNF-α (100 ng/ml) and inhibitors of protein synthesis also increased LIF mRNA in both Saos-2 and U-2 OS cells. LIF protein was also detected constitutively in the conditioned medium from both Saos and U-2 OS cells. In addition, TNF (100 ng/ml) stimulated the release of LIF protein from both these cells and PMA (2.5 ng/ml) stimulated LIF protein in Saos-2 cells. These results show that several different human malignant and rodent immortalized clonal bone cell lines can express and regulate steady-state LIF mRNA levels and produce LIF protein but that primary cultures of fetal rat osteoblastic cells do not express this cytokine. Hence, LIF may regulate malignant osteogenic cell growth and function in bone but may not be an important regulator of normal bone metabolism.
Immunoassay for urinary pyridinoline: The new marker of bone resorption
Authors: Seyedin Saeid M. , Kung Viola T. , Daniloff Yuri N. , Hesley Robert P. , Gomez Baltazar , Nielsen Lori A. , Rosen Harold N. , Zuk Robert F. 
Published: February 2010

Abstract
Urinary pyridinoline (Pyd) and deoxypyridinoline (Dpd) are markers of bone resorption that are elevated above normal in subjects with metabolic bone disease. Total Pyd and Dpd, both free and peptide-bound forms, can be measured by HPLC after hydrolysis and cellulose chromatography. Since free Pyd is the major component of total Pyd in urine, we developed an immunoassay using free Pyd as an immunogen. This assay is much easier to perform than HPLC, requires no sample preparation, and correlates well with total Pyd measurement by HPLC (r = 0.97) and with urinary hydroxyproline (r = 0.90). The antiserum reacts most strongly with free Pyd and Dpd and minimally with glycosylated and large peptide-bound forms. The sensitivity of the Pyd immunoassay is less than 25 nM. The intraassay CV is 5–10%; the interassay CV is 10–15%. Analytic recovery studies indicated negligible sample interference. Furthermore, measurement of the Pyd in the same individuals over a 30 day time period exhibited minimal day-to-day variation. Thus, the Pyd immunoassay provides a rapid and easy method for evaluation of Pyd in urine. Pyd immunoassay may serve as a practical method of screening for metabolic bone disease and for monitoring therapeutic treatment.
Mitogenic responsiveness of human bone cells in vitro to hormones and growth factors decreases with age
Authors: Pfeilschifter J. , Diel I. , Pilz U. , Brunotte K. , Naumann A. , Ziegler R. 
Published: February 2010

Abstract
Bone loss with aging may at least in part be due to inadequate bone formation. In this study, we examined whether the proliferation of osteoblast-like cells in vitro in response to local and systemic factors might be attenuated with age. A total of 36 cultures of osteoblast-like cells were obtained from outgrowths of human trabecular bone. Parathyroid hormone, growth hormone, calcitonin, transforming growth factor β, insulinlike growth factor I, and platelet-derived growth factor BB dose dependently increased DNA synthesis in all cultures. Increases in DNA synthesis with each of these factors were significantly negatively correlated with donor age in cultures obtained from the iliac crest bone of 50- to 70-year-old women. Cells from 61- to 70-year-old donors required approximately 10-fold higher concentrations of growth factors and hormones to yield comparable increases in DNA synthesis than cells from 51- to 60-year-old donors. A significant negative correlation between age and mitogenic responsiveness to platelet-derived growth factor and growth hormone, but not toward the other factors, was also observed in cultures from the femoral head trabecular bone of 60- to 90-year-old women. Our findings suggest that bone loss with aging may be partially due to a decreased capacity of osteoblasts to proliferate in response to systemic or locally released osteotropic factors.
Impact of anomalous vertebral segmentation on measurements of bone mineral density
Authors: Peel N.F.A. , Johnson A. , Barrington N.A. , Smith T.W.D. , Dr. Eastell R. 
Published: February 2010

Abstract
In anteroposterior (AP) bone mineral density (BMD) measurements of the lumbar spine (LS), the presence of ribs is used to identify vertebra T12. Similarly, in lateral LS-BMD measurements, the position of the iliac crest is used to identify the lumbar vertebrae. The aim of this study was to determine the impact of variations in spinal segmentation and iliac crest position on BMD measurements. In 375 women (ages 50–85 years) radiographs were taken of the thoracic and lumbar spine, as well as AP measurement of LS-BMD, by dual-energy x-ray absorptiometry (DXA). In 121 subjects lateral decubitus LS-BMD was also measured. Anomalous spinal segmentation was found in 16.5%, and L1 would have been incorrectly identified on the AP-DXA image in 13%. The change in BMC and BMD between adjacent vertebrae was greater in the upper than the lower lumbar spine. Misidentification of L1 for T12 resulted in underestimation of the bone mineral content in grams (BMC) of L1 by a mean of 11.5 ± 14.4% (SD; range -33.5 to 33.5%). For the usual region of interest, L2–4, the BMC (g) was underestimated by 8.4 ± 8.7% (range -1.5 to 29.2%), with the BMD (g/cm2) underestimated by 3.6 ± 4.8% (range -5.4 to 11.6%). The position of the iliac crest on the lateral decubitus DXA scans would have led to misidentification of either L2 or L4 for L3 in 15 cases (12%). This resulted in the BMD of L3 being underestimated by 2.7 ± 19.4% (range - 242.4 to 34.6%). We conclude that (1) anatomic variations in spinal segmentation are common; (2) the impact of mididentification of vertebra L1 on the AP scan is considerable if only one lumbar vertebra is studied but small if a larger area is analyzed and expressed as g/cm2; and (3) misidentification of L3 in the lateral projection can result in a large error in the BMD measurement of L3, although the mean error in terms of a population is small. Thus the impact of misidentification of lumbar vertebrae does not result in important overall changes when studying groups of subjects but on an individual basis could lead to incorrect diagnosis of osteopenia.
Isolation and complete amino acid sequence of osteocalcin from canine bone
Authors: Dr. Colombo Giovanna , Fanti Paolo , Yao Chinghua , Malluche Hartmut H. 
Published: February 2010

Abstract
Osteocalcin was purified in high yield and to homogeneity from the diaphysis of dog femora by the following steps: (1) acid demineralization of bone powder, (2) solid-phase extraction of acid-soluble proteins on Sep-Pak C18 cartridges, (3) gel filtration on Sephadex G-50, and (4) fast protein liquid chromatography on an Accell-QMA anion-exchange column. Starting from 30 g washed bone powder, approximately 7–10 mg pure protein was obtained in 2 days. The key step is the initial solid-phase extraction of osteocalcin from a large volume of a demineralized bone solution. The primary structure was established by automated sequence analyses of two tryptic peptides, of two endoproteinase Glu-C carboxy-termina) peptides, and of the first 30 amino acid residues of the intact protein. Dog osteocalcin contains 49 amino acids, has a molecular mass of 5654 daltons, contains no Thr, Met, Hyp, or Trp, has a disulfide bond between Cys 23 and 29, and is fully γ-carboxylated at residues 17, 21, and 24. Dog osteocalcin does not contain a pair of basic amino acids found at positions 43–44 in most other osteocalcins from mammals and birds. A computer search for homology indicated 88, 90, 84, 88, 66, and 57% sequence identity of dog osteocalcin with human, bovine, cat, monkey, chicken, and swordfish osteocalcin, respectively, and weaker homologies with the γ-carboxylated domains of blood-clotting proteins and the Pro-rich N-terminal extensions of myosin light-chain A1 and β-crystalline B1. The possible relevance of these homologies to the structure and potential functions of osteocalcin is discussed.
Dual-energy x-ray absorptiometry of the rat: Accuracy, precision, and measurement of bone loss
Authors: Griffin Michael G. , Kimble Robert , Hopfer Wendy , Pacifici Roberto 
Published: February 2010

AbstractDual-energy x-ray absorptiometry (DEXA) is now an established method of measuring bone mineral density (BMD) in humans. We have applied the technique to measuring BMD in the rat. The short-term precision of the technique was assessed by calculating the BMD coefficient of variation at the rat spine (1.20%), total femur (0.52%), proximal femur (1.16%), midfemur (1.00%), distal femur (0.96%), and proximal tibia (2.2%). The long-term precision of femoral measurements in rat cadavers over a 4 week period was 0.72% for the total femur and 1.2% for the distal femur. The accuracy of the technique was assessed by comparing DEXA-measured bone mineral content (BMC) in vitro and in vivo with ashed BMC. Results indicated a highly significant positive correlation between in vitro DEXA measurements and ash BMC (r = 0.99) and between in vivo DEXA measurements and ash BMC (r = 0.89). The ability of the technique to detect bone loss was assessed at the femoral site by comparing the BMD of ovariectomized (OVX) and sham-operated rats at baseline and at a 1 month follow-up. There was no significant difference in BMD between the groups at baseline. However, at 1 month follow-up the OVX group showed a significant (p &lt; 0.001) decline in BMD at the distal femur (-8.6%) and in the total femur (-4.8%) compared with sham-operated rats. A comparison of retired breeder female rats with age-matched nulliparous rats indicated that the BMD of retired breeder rats was significantly lower than that of virgin females at all femoral sites (p &lt; 0.01). The results suggest that the DEXA technique has the precision and accuracy necessary to study changes in rat BMD. Furthermore, the technique can be used quickly and noninvasively to detect a bone loss following ovariectomy in the rat, and the distal femur may be an optimal site for detecting such a bone loss.
Bone density and body composition on the pacific rim: A comparison between japan-born and u.s.-born japanese-American women
Authors: Kin Kokai , Lee Edmund J.H. , Kushida Kazuhiro , Sartoris David J. , Ohmura Akihiro , Clopton Paul L. , Inoue Tetsuo 
Published: February 2010

Abstract
Bone mineral density (BMD) of total body, spine, and proximal femur and the percentage of body fat in 151 U.S.-born Japanese-American women and 137 Japan-born immigrant Japanese-American women living in San Diego, California were measured using dual-energy x-ray absorptiometry. These data were compared with unpublished data from Japanese women obtained in previous studies in Hamamatsu, Japan. The age-adjusted BMD for the spinal level, femoral neck, Ward's triangle, trochanter, and total body, respectively, of U.S.-born Japanese-American women were 10.2, 9.8, 9.9, 9.2, and 2.7% higher than those of native Japanese women. The U.S.-born Japanese-American women had significantly higher body fat than immigrant Japanese-American women. Furthermore, the immigrant women had higher BMD and higher body fat than their native Japanese counterparts; however, no significant total-body BMD differences were found among the three groups after age, height, and weight were adjusted. The U.S.-born Japanese-American women had BMD values equivalent to those of white normals at the spine and femur. Significant life-style differences between U.S.-born and immigrant Japanese-American women were noted. Weight, exercise, early menarche, and years of lifetime estrogen exposure correlated positively with BMD. The significant negative correlates of BMD were age, smoking, and percentage of body fat. Our study presents data suggesting that immigration to the United States has produced a higher BMD in Japanese-American women that is attributable to changes in life-style and diet.
Reproductive correlates of bone mass in elderly women
Authors: Fox Kathleen M. , Magaziner Jay , Sherwin Roger , Scott Jean C. , Plato Chris C. , Nevitt Michael , Cummings Steven 
Published: February 2010

Abstract
Results from previous studies of reproductive factors and bone density have been conflicting; some demonstrate a beneficial effect, but others show a detrimental effect on bone density. The present study investigates the association of parity, lactation, and menstruation with radial bone density in 2230 white women, 65 years of age and older. Bone density was assessed by single-photon absorptiometry. Linear multiple regression was utilized to determine if reproductive factors were associated with radial bone density. The number of births, duration of menstrual bleeding, age at menarche, and years menstruating were significant independent predictors of postmenopausal bone density of the radius. A 1.4% increase in distal radius bone density was observed with each additional birth. Women who began menstruation at age 9 had 6.3% higher bone density than women who began at age 16. Women who menstruated for 3 days during each menstrual cycle had 2.8% less distal radius bone density than women who bled for 7 days. Each decade of menstruation was associated with a 2% greater distal radius bone density. No difference in bone density was demonstrated for women who breast-fed and women who did not. Length of the menstrual cycle, amount of menstrual flow, and irregularity of the menstrual cycle were not significantly associated with radial bone mineral density. In conclusion, pregnancy and menstruation are associated with postmenopausal bone density of the radius.