bluuebunny/crossref_metadata_2025_split huggingface dataset:
The relations between physical ability and bone mass in women aged over 65 years
Authors: Vico Laurence , Pouget Jean Francois , Calmels Paul , Chatard Jean Claude , Rehailia Mohamed , Minaire Pierre , Geyssant André , Alexandre Christian 
Published: February 2010

Abstract
In this cross-sectional study of 55 women (mean age 73.54 ± 5.87), the magnitude of the relation between different indices of physical ability and confounding factors to bone density were determined. Physical fitness was assessed by direct measurement of maximal oxygen consumption (V̇O2 max), isokinetic muscle strength, and quadriceps and psoas muscle surfaces and densities using computed tomography. Anthropometry, chronological and gynecological ages, and dietary calcium intake were also recorded. The bone mineral density (BMD) was evaluated at the axial level (lumbar spine and proximal femur) and at the peripheral level (radius and tibia, cancellous and cortical compartments). Parameters related to physical ability proved to be the best predictors of BMD in radial and tibial cancellous compartments, spine, femoral neck, and trochanter, accounting for 15–27.5% of the total variance. The V̇O2 max was a major determinant of the femoral mineral density and one of the predictors of radial and tibial cancellous compartments. Psoas parameters were strongly related to spine mineral density and also constituted a predictor of radius (cancellous) and tibia mineral densities. The arm muscle strength could predict, though weakly, the BMD of axial skeleton, whereas thigh muscle strength only predicted the BMD of inferior limbs. No correlation was observed between current dietary calcium intake and BMD. Age-postmenopause and fertile life remained predictive of BMD at mostly cancellous sites, whereas anthropometry exerted important effects on radial and tibial cortices. The study suggests distinct sets of relations between physical ability and the BMD variables. Subjects with greater and denser psoas muscles had greater spine BMD, and those with higher V̇O2 max had greater proximal femur BMD.
Bone density in young women is associated with body weight and muscle strength but not dietary intakes
Authors: Henderson N. Kathryn , Price Roger I. , Cole Joan H. , Gutteridge Donald H. , Bhagat Chotoo I. 
Published: February 2010

Abstract
Potential determinants of bone mineral density (BMD) were studied cross-sectionally in 115 healthy, sexually mature Caucasian women aged 18 years. Bone mineral density (Hologic QDR1000W) of the lumbar spine, proximal femur (five sites), and distal tibia and fibula; fasting blood and urine calcium biochemistry; serum sex hormone levels (follicular phase); nutrient intakes; aerobic fitness; trunk muscle strength; and habitual activity levels were measured. The effects of heredity were considered by measuring the BMD of 107 of the subjects' mothers. Simple and stepwise regression analysis were used to identify significant determinants of BMD at each of the regions studied. The analysis indicated that significant bivariate correlations exist between BMD at all sites and body weight (r = 0.23–0.47, p ≤ 0.01), lean body weight (r = 034–0.46), trunk strength (r = 0.27–0.47), physical activity score (r = 0.20–0.25), and aerobic fitness (r = 0.29–0.45). Dietary calcium intake correlated significantly with BMD at the trochanter site only (r = 0.19), and none of the biochemical or hormonal indices measured correlated consistently with BMD at any site. Significant correlations between the BMD of mothers and daughters ranged from r = 0.43 at lumbar spine to r = 0.34 at the intertrochanteric site. Paired t-tests showed the daughters had significantly (p &lt; 0.03) lower BMD than their mothers at the lumbar spine (98 ± 12% [mean ± SD]) and significantly higher (p &lt; 0.002) BMD at the femoral neck, trochanter, and total hip sites (110 ± 16%, 108 ± 17%, 103 ± 14%, respectively). When stepwise regression analysis included weight-corrected strength of the trunk flexor muscles (Corr Flex), weight-corrected aerobic fitness (Corr VO2max), physical activity score, and body weight, body weight was the only significant determinant of BMD at all sites. Corr Flex made significant contributions at all sites except the femoral neck, while Corr VO2max made additional contribution at the femoral neck, trochanter, total hip, and shaft of femur sites. These variables accounted for 13–27% of the variance in BMD. The addition of mother's BMD to these independent variables, in stepwise regression analysis, improved the prediction to 18–31% of the variance.
Expression of bone morphogenetic protein-6 messenger RNA in bovine growth plate chondrocytes of different size
Authors: Carey Dennis E. , Liu Xia 
Published: February 2010

Abstract
Bone morphogenetic protein-6 (BMP-6) is an osteoinductive factor that may have a regulatory role in the terminal differentiation of chondrocytes. We investigated the expression of BMP-6 messenger RNA in freshly isolated newborn calf rib chondrocytes separated by density gradient centrifugation into five highly enriched subpopulations at different stages of maturation as assessed by cell size and alkaline phosphatase activity. Expression of BMP-6 mRNA was compared with expression of type II collagen mRNA and type X collagen mRNA using Northern analysis. Type X collagen mRNA expression increased with increasing cell size whereas type II collagen mRNA varied little with cell size. BMP-6 mRNA expression was highest in small cells and lowest in the largest cells, which were maximally expressing type X collagen mRNA. This suggests that up-regulation of the BMP-6 gene may precede chondrocyte hypertrophy.
Upper extremity bone mass and osteoarthritis of the knees: Data from the baltimore longitudinal study of aging
Authors: Dr. Hochberg Marc C. , Lethbridge-Cejku Margaret , Scott William W. , Reichle Ralph , Plato Chris C. , Tobin Jordan D. 
Published: February 2010

Abstract
To examine the association of upper extremity bone mass with osteoarthritis (OA) of the knee, bilateral standing knee radiographs, taken between 1985 and 1991, in 430 Caucasian male and 266 Caucasian female subjects aged 40 years and above in the Baltimore Longitudinal Study of Aging, were read by one investigator for grade of OA using Kellgren-Lawrence scales. Several measures of upper extremity bone mass, size, and density, including combined cortical thickness (CCT), total width and percentage of cortical area of the second metacarpal, and bone mineral content (BMC), width, and density of the distal third of the left radius measured with single photon absorptiometry, were assessed at the same visit. In univariate analyses, men and women with definite knee OA were significantly older, men had significantly greater radial width, and women had significantly lower bone mass as measured by both CCT and BMC. After adjustment for age and body weight, however, men with knee OA had significantly higher BMC and radial width while neither of these measures of upper extremity bone mass and size was significantly associated with the presence of definite knee OA in women. Neither measure of upper extremity bone density was significantly associated with definite knee OA in either sex. These data suggest that, although men (but not women) with definite knee OA have significantly higher levels of adjusted radial bone mass and size, subjects with knee OA do not have significantly higher levels of adjusted bone mineral density at either upper extremity site.
Regulation of parathyroid hormone messenger RNA levels by protein kinase A and C in bovine parathyroid cells
Authors: Moallem Eli , Silver Justin , Naveh-Many Tally 
Published: February 2010

Abstract
Secretion of parathyroid hormone (PTH) is regulated by Ca2+ as well as by protein kinases A and C. In this study we report that protein kinases A and C regulate PTH messenger RNA levels in vitro in dispersed bovine parathyroid cells. Incubation of bovine parathyroid cells with cholera toxin (10−9 M), which activates adenylate cyclase and indirectly stimulates protein kinase A, increased PTH mRNA levels about 2-fold after 3 and 7 h incubation, but not at 24 h. Incubation with pertussis toxin (5 × 10−9 M), which blocks the high-calcium-mediated inhibition of cyclic adenosine monophosphate accumulation in these cells, also reversed the inhibition of PTH mRNA levels at high Ca2+ (2.0 mM) with a marked increase in PTH mRNA levels. Pertussis toxin also increased PTH mRNA at a low extracellular Ca2+ concentration (0.7 mM) (4-fold increase) and a normal concentration (1.25 mM) (2-fold increase). Inhibition of protein kinase C both by staurosporine (1 × 10−8 M) and by prolonged incubation with the phorbol ester phorbol 12-myristate 13-acetate (PMA) (1 × 10−7 M), decreased PTH mRNA levels at 24 h, reaching approximately 40% and 5% of control, respectively. Staurosporine and PMA had no effect on PTH mRNA levels at 3 h. The inactive phorbol ester, phorbol 12–13-diburyrate (PDBu), had no effect on PTH mRNA levels at 1 and 24 h. There were no changes in a control gene 18S RNA in these studies. PMA at 24 h, which may down-regulate protein kinase C activity, decreased PTH mRNA levels, suggesting that protein kinase C is necessary for normal PTH gene expression. These results suggest that both protein kinase A and C are involved in the regulation of PTH gene expression.
Human parathyroid hormone-(1–38) restores cancellous bone to the immobilized, osteopenic proximal tibial metaphysis in rats
Authors: Ma Y.F. , Jee W.S.S. , Ke H.Z. , Lin B.Y. , Liang X.G. , Li M. , Yamamoto N. 
Published: February 2010

Abstract
The purpose of this study was to determine if human parathyroid hormone-(1–38) (hPTH(1–38)) can restore cancellous bone mass to the established osteopenic, immobilized proximal tibial metaphyses of female rats. The right hindlimbs of 6-month-old female Sprague-Dawley rats were immobilized by bandaging the right hindlimbs to the abdomen. After 30 days of right hindlimb immobilization, the rats were subcutaneously injected with 200 μg hPTH(1–38)/kg/day for 15 days (short-term treatment) or 75 days (longer-term treatment). Static bone histomorphometry was performed on the primary spongiosa, and both static and dynamic histomorphometry were performed on the secondary spongiosa of the right proximal tibial metaphyses. Immobilization for 30 days without treatment decreased trabecular bone area, number, and thickness in both primary and secondary spongiosa, and induced an increase in eroded perimeter and a decrease in tissue referent-bone formation rate in the secondary spongiosa. These changes reached a new steady state thereafter. Treatment with 200 μg hPTH(1–38)/kg/day for 15 days, beginning 30 days after immobilization, significantly increased trabecular bone area, thickness, and number in both primary and secondary spongiosa despite continuous immobilization when compared with controls. The short-term PTH treatment (15 days) significantly increased labeling perimeter, mineral apposition rate, and tissue referent-bone formation rate in the secondary spongiosa and stimulated longitudinal bone growth as compared with the controls. Longer PTH treatment (75 days) further increased trabecular bone area, thickness, and number as compared with controls and groups given short-term PTH treatment (15 days). The bone formation indices in the secondary spongiosa of the longer-term treated rats were lower than those of the short-term treated group, but they were still higher than those of controls. Our findings indicate that PTH treatment stimulates cancellous bone formation, and restores and adds extra cancellous bone to the established, disuse-osteopenic proximal tibial metaphysis of female rats with continuously immobilized right hindlimbs. These results suggest that PTH may be useful in treating disuse-induced osteoporosis in humans.
Determinants of bone mass in 10- to 26-year-old females: A twin study
Authors: Young Doris , Hopper John L. , Nowson Caryl A. , Green Robyn M. , Sherwin Jane A. , Kaymakci Bahtiyar , Smid Monique , Guest Charles S. , Larkins Richard G. , Wark John D. 
Published: February 2010

Abstract
This cross-sectional twin study aimed to quantify the roles of constitutional and lifestyle factors on bone mass in adolescent and young adult women. Areal bone density (BMD) at the lumbar spine, femoral neck, Ward's triangle, and total hip, total body bone mineral content (BMC), and lean mass and fat mass were measured using dual energy X-ray absorptiometry (DXA) in 215 female volunteer twin pairs (122 monozygotic [MZ], 93 dizygotic [DZ]) aged 10 to 26 years. Height, weight, menarchial history, dietary calcium intake, physical activity, current tobacco use, and alcohol consumption were determined by questionnaire. Mean BMD increased with age to around 16 years, when it reached a plateau. Within-pair differences in BMD at the lumbar spine (expressed as a percentage of the pair mean BMD) were univariately associated with pair differences in menarchial status (14 ± 3%), height (0.7 ± 0.1% per cm), weight (0.4 ± 0.1% per kg), lean mass (1.0 ± 0.1% per kg), and fat mass (0.5 ± 0.1% per kg). Only menarchial status, height, and lean mass, however, were independent predictors. At the proximal femoral sites, within-pair BMD differences were associated with within-pair lean mass differences (1.0 to 1.1 ± 0.2%/kg), and no other factor was significant. The same conclusions applied to within-pair differences in BMD/height. Total body BMC was independently associated with menarchial status, height, lean mass, and fat mass; the effects of the latter two variables were stronger in pairs both premenarchial. After adjusting for constitutional factors, no lifestyle factor was independently predictive. By reducing collinearity, the cotwin method clearly identified that lean mass, not fat mass, was the major independent determinant of bone mass at the hip, both pre- and postmenarche.
Casein kinase localization in the endoplasmic reticulum of the ros 17/2.8 cell line
Authors: Sfeir Charles , Veis Arthur 
Published: February 2010

Abstract
Phosphophoryns (PPs) are phosphoproteins specific to the dentin matrix and are the major noncollagenous matrix proteins in rat incisor dentin. It has been hypothesized that their phosphate groups are important in dentin mineralization. PPs have many sequences which are substrates for membrane-associated endogenous messenger-independent kinases.(12) The objective of this study was to localize the protein kinases involved in phosphorylating the PPs. Osteoblast-like ROS 17/2.8 cells, which secrete extracellular matrix phosphoproteins, were lysed. After removal of the nuclei and mitochondria by low-speed centrifugation, the membrane associated organelles were isolated at higher speed from the cytosol. The Golgi vesicle and rough microsome fractions were collected from 29–43.7% sucrose density gradients. Each fraction was tested for casein kinase II (CKII) activity using an in vitro phosphorylation assay with PPs as substrate. To characterize and confirm the nature of the components of the sucrose gradient fractions, the activities of specific enzymes such as N-acetylglucosamine galactosyltransferase and cytochrome c reductase, which are exclusively associated with the Golgi and rough microsomes, respectively, were determined. Electron microscopy of the isolated fractions confirmed the enzyme assay characterizations. CKII activity capable of phosphorylating the PP was found in the rough microsome fraction but not in the Golgi. Thus, phosphorylation of the secreted phosphoproteins would appear to take place in the endoplasmic reticulum as a cotranslational event.
Frequency and characteristics of familial aggregation of paget's disease of bone
Authors: Morales-Piga A.A. , Rey-Rey J.S. , Corres-González J. , Garc ÍA-Sagredo J.M. , LÓPez-Abente G. 
Published: February 2010

Abstract
The cause of Paget's disease of bone (PDB) is unknown. In an attempt to ascertain the proportion of familial cases and evaluate the influence of genetic factors on the occurrence of the disease, a study was undertaken based on 35 PDB patients from our Unit. Their families were investigated, with the participation of a total of 128 first-degree relatives. Fourteen (40%) of these 35 index cases had at least one other first-degree relative affected with PDB and were defined as “familial.” The remaining 21 (60%) were considered “sporadic.” The frequency of males in the familial cases (79%) was significantly higher than among the sporadics (29%; p ≤ 0.01). Mean age at diagnosis (63.1  12.6 vs. 713 ± 8.7; p ≤ 0.02), proportion of polyostotic cases (85.7% vs. 52.4%, p ≤ 0.05), and mean number of involved bones per patient (436 ± 2.50 vs. 233 ± 1.93, p ≤ 0.01) differ significantly in the familial and sporadic groups. The disease appears to be transmitted via both paternal and maternal sides, and pedigree analysis suggested an autosomal dominant inheritance or multifactorial mechanism. Apart from green-and-blue eye color, which was clearly associated with familial grouping (OR 6.25, 95% CI 1.15–37.16, p ≤ 0.01), crude analysis on several genetically based traits and environmental variables revealed no other significant differences between the groups. The adjusted odds ratio estimated for green-and-blue eye color was 2.92 (95% CI 038–22.74). Although additional studies will be required to determine whether the high proportion of familial cases and the differences between these and the sporadic cases also exist in different geographic areas, our data support the existence of two distinct subtypes of PDB.
Inhibition of bone resorption and stimulation of formation by mechanical loading of the modeling rat ulna in vivo
Authors: Hillam Richard A. , Dr. Skerry Timothy M. 
Published: February 2010

Abstract
During normal growth of the rat ulna, bone is resorbed from the medial periosteal surface. This occurs as part of the modeling process by which the bone achieves its adult shape. By attaching strain gauges to the ulnae of rats in vivo, we measured the strains imposed on that surface of the bone during normal locomotion. We then applied mechanical loads to the ulnae of other rats in vivo for 6 consecutive days, inducing strains approximately double those we had measured. Fluorochromes were given on the 1st and 5th days. The histology of the medial ulnar periosteal surface was correlated with the amount of fluorochrome incorporation and tartrate resistant acid phosphatase (TRAP) activity in serial sections. In the nonloaded ulnae, the surfaces were lined with bone resorbing cells. Corresponding areas of the loaded bones were lined with osteoid and osteoblasts. There was insignificant label incorporation in the nonloaded bones but almost continuous label incorporation in the corresponding regions of the loaded bones, which was significantly different from the nonloaded bones. TRAP activity of the periosteal cells in the loaded bones was significantly less than in the nonloaded limbs. It is widely acknowledged that loading induces bone formation, and this implies that it also has the ability to inhibit resorption. However, to date there has been little direct evidence for the inhibition of resorption in vivo by mechanical loading. The changes we have observed are similar to the sequence of cellular events that occur during the reversal phase of bone remodeling, in which osteoclastic resorption ceases and osteoblasts are recruited and begin formation. This model may help increase understanding of that process.
Osteogenic growth peptide regulates proliferation and osteogenic maturation of human and rabbit bone marrow stromal cells
Authors: Robinson D. , Bab I. , Prof. Nevo Z. 
Published: February 2010

Abstract
The recently discovered osteogenic growth peptide (OGP) has been shown to regulate proliferation in fibroblastic and osteoblastic cell lines derived from rats and mice and also alkaline phosphatase activity in the latter was found to be affected. In vivo the OGP enhances bone formation and trabecular bone density. The results of the current study indicate that the OGP is also a potent regulator of marrow stromal cells from man and rabbit, as well as rabbit muscle fibroblasts. The main OGP activity in both marrow systems is a marked stimulation of alkaline phosphatase activity and matrix mineralization. In the rabbit-derived cell culture this enhancement is accompanied by a reciprocal inhibition of proliferation. On the other hand, the human cells show a concomitant increase of both parameters. The proliferative effect of the OGP is similar to that of growth hormone (GH) and basic fibroblast growth factor (bFGF). The combined activity of the OGP with GH is smaller than that of each of the polypeptides alone. The OGP and bFGF potentiate each other. Of the three polypeptides tested, OGP is the most potent enhancer of alkaline phosphatase activity and mineralization. bFGF has no influence on these characteristics of osteogenic maturation. The OGP maturational activity is unaffected by either GH or bFGF. These data suggest that the marrow stromal cells serve as targets for the OGP that mediate the OGP-induced increase in osteogenesis. The effect on the human cells implies a role for the OGP in clinical situations where the osteogenic potential of bone marrow is involved.
Plasma levels of parathyroid hormone-related peptide are elevated in hyperprolactinemia and correlated to bone density status
Authors: Stiegler Claudia , Leb Georg , Kleinert Reinhold , Warnkross Helga , Ramschak-Schwarzer Sigrid , Lipp Rainer , Clarici Georg , Krejs Guenter J. , Dobnig Harald 
Published: February 2010

Abstract
Osteopenia is an important clinical manifestation of hyperprolactinemia. Bone loss in these patients has mainly been attributed to concomitant deficiency of gonadal hormones rather than to hyperprolactinemia per se. Parathyroid hormone-related peptide (PTHrP) is expressed in human mammary tissue, and elevated circulating PTHrP levels as well as concomitant hypercalcemia have been described during lactation. We sought to determine circulating PTHrP levels in patients with long-standing hyperprolactinemia and whether PTHrP may exert possible systemic effects on bone and mineral metabolism. We studied 45 patients (30 women and 15 men) with persisting hyperprolactinemia 6 ± 4 years (mean ± SD) after trans-sphenoidal surgery for prolactin-producing pituitary adenomas. PTHrP levels in 117 healthy controls were 10.6 ± 73 pmol-eq/l (mean ± SD). In hyperprolactinemic patients, plasma PTHrP was elevated to 303 ± 13.4 pmol-eq/l (p &lt; 0.001, n = 45), and in patients with humoral hypercalcemia of malignancy PTHrP levels were 52.9 ± 29.6 (p &lt; 0.001 to controls and hyperprolactinemic patients). Fifty-three percent of hyperprolactinemic patients (n = 24) had clearly elevated PTHrP levels (&gt;2 SD). Retrospective immunocytochemical studies of the removed pituitary adenomas from 19 patients generally showed a higher degree of immunoreactivity for PTHrP (1–34) in all but one case when compared with normal pituitary tissue. Patients with elevated circulating PTHrP levels showed in most instances strong immunoreactivity to PTHrP in 70–100% of tumor cells. PTHrP was significantly correlated to blood pressure (systolic: r = –0.42, p &lt; 0.005; diastolic: r = –0.41, p &lt; 0.01), serum calcium (r = 0.40, p &lt; 0.01), parathyroid hormone (r = –0.43, p &lt; 0.005), and bone density measurements (r = –0.41, p &lt; 0.005). Patients taking low doses of bromocriptine (n = 15) had similar reductions in bone mineral density despite lower prolactin levels (p &lt; 0.005), and there was no correlation between either prolactin levels or estrogen status and bone mineral density measurements (r = –0.12 and r = –0.28, respectively). Our data demonstrate that circulating PTHrP levels are clearly elevated in approximately 50% of patients with pituitary hyperprolactinemia and suggests the pituitary adenomas to be the major source of PTHrP production. Independent of gonadal function and the degree of hyperprolactinemia, PTHrP functions as an active hormone and contributes substantially to bone loss seen in these patients.