bluuebunny/crossref_metadata_2025_split huggingface dataset:
Osteoporosis in Elderly Men and Women: Effects of Dietary Calcium, Physical Activity, and Body Mass Index
Authors: Nguyen T. V. , Center J. R. , Eisman J. A. 
Published: April 2006

Abstract
Dietary calcium intake and physical activity are considered practical measures for prevention of osteoporosis. However, their associations with bone mineral density (BMD) in the elderly are not clear. The present study examined the association between osteoporosis and these two factors in relation to body mass index (BMI) in a cross-sectional, epidemiological study involving 1075 women and 690 men, aged 69 ± 6.7 years (mean ± SD). Dietary calcium intake (median of 580 mg/day) was inversely related to age (p = 0.01), positively related to physical activity index (PAI) (p = 0.01), femoral neck BMD (p = 0.01) in women, and higher lumbar spine (p = 0.003) and femoral neck BMD (p = 0.03) in men. Quadriceps strength was negatively associated with age (p &lt; 0.0001) and positively related to BMI (p &lt; 0.0001) and BMD (p &lt; 0.0001) in both men and women. The PAI was associated with quadriceps strength (p &lt; 0.0001) and femoral neck and lumbar spine BMD in women (p &lt; 0.001) and with femoral neck BMD in men (p = 0.04); however, these associations were not significant after adjusting for age, BMI, quadriceps strength, and dietary calcium. Women in the top tertile of quadriceps strength (≥23 kg) and dietary calcium intake (≥710 mg/day) had 15% higher BMD than those in the lowest tertiles (≤15 kg and ≤465 mg/day); the difference was comparable in men (11%). Among subjects with the lowest tertiles of BMI (≤23 kg/m2 for women and ≤24 kg/m2 for men), quadriceps strength (≤15 kg for women and ≤28 kg for men), and dietary calcium intake (≤465 mg/day), 64% and 40% of women and men, respectively, were classified as having osteoporosis (based on a 2.5-SD reduction from the young-normal mean). The prevalence was only 12% in women and 1.5% in men among those in the highest tertiles of the three factors. Adequate dietary calcium intake and maintaining a physically active lifestyle in late decades of life could potentially translate into a reduction in the risk of osteoporosis and hence improve the quality and perhaps quantity of life in the elderly population. (J Bone Miner Res 2000;15:322–331)
Enhanced Expression of Osteocalcin mRNA in Human Osteoarthritic Trabecular Bone of the Proximal Femur Is Associated with Decreased Expression of Interleukin-6 and Interleukin-11 mRNA
Authors: Kuliwaba Julia S. , Findlay David M. , Atkins Gerald J. , Forwood Mark R. , Fazzalari Nicola L. 
Published: April 2006

Abstract
Few studies have investigated the factors or mechanisms that may lead to structural changes in OA bone. This study examines the in vivo expression of messenger RNA encoding the osteoclastogenic cytokines interleukin-6 (IL-6) and interleukin-11 (IL-11), together with the osteoblastic marker osteocalcin (OCN) and the calcitonin receptor (CTR), which in bone is exclusively expressed by osteoclasts. Total RNA was isolated from intertrochanteric trabecular bone from OA patients, and from controls taken at autopsy. The patterns of mRNA expression of IL-6, IL-11, OCN, and CTR were examined using reverse-transcription polymerase chain reaction (RT-PCR) by determining the relative ratios of the amplified products with respect to glyceraldehyde-3-phosphate dehydrogenase (GAPDH). Both IL-6 and IL-11 mRNA were significantly less abundant in OA than in the control group. Expression of IL-11 mRNA decreased significantly with age for both groups. OCN mRNA expression was significantly more abundant in OA, and there was no significant difference for CTR mRNA between the two groups. For both OCN and CTR in OA, expression increased significantly with increasing age. These differences in expression between the OA and control groups are consistent with an hypothesis that biochemical and genetic factors in bone can contribute or perhaps underlie the degenerative joint changes seen in OA. (J Bone Miner Res 2000;15:332–341)
Association of Transforming Growth Factor β1 Genotype with Therapeutic Response to Active Vitamin D for Postmenopausal Osteoporosis
Authors: Yamada Yoshiji , Harada Atsushi , Hosoi Takayuki , Miyauchi Akimitsu , Ikeda Kyoji , Ohta Hiroaki , Shiraki Masataka 
Published: April 2006

Abstract
Transforming growth factor β (TGF-β) is an important regulator of bone metabolism, its effects being intertwined with those of estrogen and vitamin D. A T→C polymorphism in exon 1 of the TGF-β1 gene, which results in the substitution of proline for leucine, is associated with bone mineral density (BMD). However, it is not known whether this polymorphism affects the response to treatment with active vitamin D or to hormone replacement therapy (HRT) in individuals with osteoporosis. Changes in BMD at the lumbar spine (L2–L4 BMD) were compared among TGF-β1 genotypes in 363 postmenopausal Japanese women who were divided into three groups: an untreated, control group (n = 130), an active vitamin D treatment group (n = 117), and an HRT group (n = 116). TGF-β1 genotype was determined with an allele-specific polymerase chain reaction assay. In the control group, the rate of bone loss decreased according to the rank order of genotypes TT (homozygous for the T allele) &gt; TC (heterozygous) &gt; CC (homozygous for the C allele), with a significant difference detected between the CC and TT genotypes. The positive response of L2–L4 BMD to HRT increased according to the rank order of genotypes TT &lt; TC &lt; CC, although the differences among genotypes were not statistically significant. Individuals with the CC genotype responded to active vitamin D treatment with an annual increase in L2–L4 BMD of 1.6%, whereas those with the TT or TC genotypes similarly treated lost bone to a similar extent as did untreated subjects of the corresponding genotype. These results suggest that TGF-β1 genotype is associated with both the rate of bone loss and the response to active vitamin D treatment.
Genomic Organization of the Human Chondromodulin-1 Gene Containing a Promoter Region That Confers the Expression of Reporter Gene in Chondrogenic ATDC5 Cells
Authors: Yanagihara Itaru , Yamagata Masayo , Sakai Norio , Shukunami Chisa , Kurahashi Hiroki , Yamazaki Miwa , Michigami Toshimi , Hiraki Yuji , Ozono Keiichi 
Published: April 2006

Abstract
Chondromodulin-1 (ChM-1) is a cartilage-specific glycoprotein that stimulates the growth of chondrocytes and inhibits the tube formation of endothelial cells. To clarify the tissue-specific expression and the role of ChM-1 in pathophysiological conditions, we analyzed the structure of the human ChM-1 gene and its promoter. On the screening of a human genomic cosmid library using the human ChM-1 complimentary DNA (cDNA) as a probe, two clones were obtained that contained ChM-1 cDNA. The restriction enzyme map and nucleotide sequence revealed the human ChM-1 gene consisting of seven exons and exon-intron boundaries. The human ChM-1 gene was assigned to chromosome 13q14–21 by fluorescence in situ hybridization (FISH) using the clone as a probe. A primer extension analysis using total RNA extracted from human cartilage revealed a major transcription start site with the sequence CGCT+1GG. The region approximately 3-kilobase (kb) nucleotides upstream of the translation start site was then sequenced and analyzed in terms of promoter activity. We found that a region 446 base pairs (bp) upstream of the start site had promoter activity in COS7, HeLa, and ATDC5 cells. In structure the promoter is a TATA-less type without a GC-rich region. The transcription factors Sox9, Og12, and Cart-1 did not affect the promoter activity. The transcription factor Ying-Yang1 suppressed the promoter activity but GABP protein did not change the promoter activity. The construct containing −446/+87 fused to the SV40 enhancer and green fluorescent protein (GFP) exhibited expression of GFP corresponding to the differentiation of ATDC5 cells to mature chondrocytes. These results suggest that the element −446/+87 confers the cartilage-specific expression of this gene by some factor(s) other than Sox9, Og12, and Cart-1.
Cytoskeletal Abnormalities in Chondrocytes with EXT1 and EXT2 Mutations
Authors: Bernard Mark A. , Hogue Deborah A. , Cole William G. , Sanford Tiffany , Snuggs Mark B. , Montufar-Solis Dina , Duke P. Jackie , Carson Daniel D. , Scott Allison , Barry Van Winkle W. , Dr. Hecht Jacqueline T 
Published: April 2006

Abstract
The EXT genes are a group of putative tumor suppressor genes that previously have been shown to participate in the development of hereditary multiple exostoses (HME), HME-associated and isolated chondrosarcomas. Two HME disease genes, EXT1 and EXT2, have been identified and are expressed ubiquitously. However, the only known effect of mutations in the EXT genes is on chondrocyte function as evidenced by aberrant proliferation of chondrocytes leading to formation of bony, cartilage-capped projections (exostoses). In this study, we have characterized exostosis chondrocytes from three patients with HME (one with EXT1 and two with EXT2 germline mutations) and from one individual with a non-HME, isolated exostosis. At the light microscopic level, exostosis chondrocytes have a stellate appearance with elongated inclusions in the cytoplasm. Confocal and immunofluorescence of in vitro and in vivo chondrocytes showed that these massive accumulations are composed of actin bundled by 1.5-μm repeat cross-bridges of α-actinin. Western blot analysis shows that exostosis chondrocytes from two out of three patients aberrantly produce high levels of muscle-specific α-actin, whereas β-actin levels are similar to normal chondrocytes. These findings suggest that mutations in the EXT genes cause abnormal processing of cytoskeleton proteins in chondrocytes.
Direct and Indirect Actions of Fibroblast Growth Factor 2 on Osteoclastic Bone Resorption in Cultures
Authors: Kawaguchi Hiroshi , Chikazu Daichi , Nakamura Kozo , Kumegawa Masayoshi , Hakeda Yoshiyuki 
Published: April 2006

Abstract
Fibroblast growth factor 2 (FGF-2 or basic FGF) is known to show variable actions on bone formation and bone resorption. This study was undertaken to elucidate the mechanisms whereby FGF-2 affects bone metabolism, especially bone resorption, using three different culture systems. FGF-2 at 10−9 M and higher concentrations induced osteoclastic cell formation in the coculture system of mouse osteoblastic cells and bone marrow cells, and this induction was abrogated by nonsteroidal anti-inflammatory drugs (NSAIDs). 45Ca release from prelabeled cultured mouse calvariae stimulated by FGF-2 (10−8 M) was also inhibited by NSAIDs, and the inhibition was stronger by NSAIDs, which are more selective for inhibition of cyclooxygenase 2 (COX-2) than COX-1, suggesting the mediation of COX-2 induction. COX-2 was highly expressed and its messenger RNA (mRNA) level was stimulated by FGF-2 in osteoblastic cells whereas it was undetectable or not stimulated by FGF-2 in cells of osteoclast lineage. To further investigate the direct actions of FGF-2 on osteoclasts, resorbed pit formation was compared between cultures of purified osteoclasts and unfractionated bone cells from rabbit long bones. FGF-2 (≥10−12 M) stimulated resorbed pit formation by purified osteoclasts with a maximum effect of 2.0-fold at 10−11 M, and no further stimulation was observed at higher concentrations. However, FGF-2 at 10−9 M − 10−8 M stimulated resorbed pit formation by unfractionated bone cells up to 9.7-fold. NS-398, a specific COX-2 inhibitor, did not affect the FGF-2 stimulation on purified osteoclasts but inhibited that on unfractionated bone cells. We conclude that FGF-2 at low concentrations (≥10−12 M) acts directly on mature osteoclasts to resorb bone moderately, whereas at high concentrations (≥10−9 M) it acts on osteoblastic cells to induce COX-2 and stimulates bone resorption potently.
Culture in Vector-Averaged Gravity Under Clinostat Rotation Results in Apoptosis of Osteoblastic ROS 17/2.8 Cells
Authors: Sarkar Devanand , Dr. Nagaya Takashi , Koga Kazuo , Nomura Yoshio , Gruener Raphael , Seo Hisao 
Published: April 2006

Abstract
Space flight experiments and studies carried out in altered gravity environments have revealed that exposure to altered gravity conditions results in (mal)adaptation of cellular function. In the present study, we used a clinostat to generate a vector-averaged gravity environment. We then evaluated the responses of osteoblast-like ROS 17/2.8 cells subsequent to rotation at 50 revolutions per minute (rpm) for 6–24 h. We found that the cells started to detach from the substrate between 12 h and 24 h of rotation in clinostat but not in stationary cultures or after horizontal rotation (the latter serving as a motion control for turbulence, shear forces, and vibrations). At 24 h, 35% of clinorotated cells had detached and the cells underwent apoptotic death as evidenced by DNA fragmentation analysis, terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-biotin nick end labeling (TUNEL) staining, and flow cytometry with Annexin V staining. The apoptotic death was associated with perinuclear distribution of cell-surface integrin β1 and disorganization of actin cytoskeleton. These results suggest that vector-averaged gravity causes apoptosis of osteoblasts by altering the organization of the cytoskeleton. We hypothesize that apoptotic death of osteoblasts might play an important role in the pathogenesis of osteoporotic bone loss as observed in actual space flights.
Direct Action of Naturally Occurring Estrogen Metabolites on Human Osteoblastic Cells
Authors: Robinson John A. , Waters Katrina M. , Turner Russell T. , Spelsberg Thomas C. 
Published: April 2006

Abstract
This article describes experiments that were performed to examine the direct action of estrogen metabolites on cultured human osteoblast cells. The human fetal osteoblastic cell line, hFOB/ER9, which expresses high levels of the estrogen receptor (ER) alpha, was used to examine the direct effects of 16α-hydroxyestrone (16α-OHE1) and 2-hydroxyestrone (2-OHE1) on osteoblast differentiation. The 16α-OHE1 caused a decrease in osteocalcin (OC) secretion to a maximum of 40% of control values (vehicle-treated cells) at 10−7 M. Alkaline phosphatase (AP) activity was significantly induced at 10−7 M 16α-OHE1 with greater than 500% of control at 10−6 M 16α-OHE1. Finally, AP steady-state messenger RNA (mRNA) levels were increased within 24 h of 16α-OHE1 treatment. In contrast to 16α-OHE1, 2-OHE1 had no effects on the secretion of OC, AP activity, or AP gene expression. The 2-OHE1 also did not display any antiestrogen activity because treatment in combination with 17β-estradiol (E2) and 16α-OHE1 had no significant effect on the reduction in OC secretion or induction of AP activity. Similar to E2, 16α-OHE1 stimulated the expression of an early response gene, a TGF-β inducible early gene, designated TIEG, as early as 60 minutes after treatment, whereas treatment with 2-OHE1 displayed no effect. Support that the 16α-OHE1 regulation of these osteoblasts (OB) markers was mediated through the ER is shown by the fact that the estrogen antagonist ICI 182,780 abrogated these effects. These data suggest that 16α-OHE1 is a potent estrogen agonist on human osteoblastic hOB/ER9 cells. In contrast, 2-OHE1 displayed no estrogenic or antiestrogenic activity in this human osteoblast cell model.
Bone Has a Sexually Dimorphic Response to Aromatase Deficiency
Authors: Öz Orhan K. , Zerwekh Joseph E. , Fisher Carolyn , Graves Kathy , Nanu Lydia , Millsaps Rita , Simpson Evan R. 
Published: April 2006

Abstract
Aromatase synthesizes estrogen from androgen precursors. To better understand the role of estrogen in skeletal metabolism and growth, we have assessed long bone growth and histomorphometry in aromatase-deficient (ArKO) mice. The age range for the animals was 5–7 months. At this age mice have already achieved peak bone density but continue slow bone growth. Femur length, an index of long bone growth, showed decreased growth in ArKO males compared with wild-type (wt) littermates but no significant difference in females. Radiographically, compared with age- and sex- matched littermates both ArKO males and females showed osteopenia in the lumbar spine. Histologically, both ArKO males and females showed an osteoporotic-type picture, characterized by significant decreases in trabecular bone volume and trabecular thickness. However, compared with wt littermates female ArKO animals showed a bone remodeling picture consistent with increased bone turnover, much like early postmenopausal osteoporosis in humans. On the other hand, male ArKO animals showed decreases in both osteoblastic and osteoclastic surfaces compared with wt littermates, similar to age-related osteopenia. These findings suggest that osteoporosis seen in aromatase-deficient mice may arise from different bone remodeling activities between males and females. These results also show that the ArKO model exhibits the expected results of estrogen deficiency and may be a good model for investigating sex-specific responses to estrogen deficiency. Furthermore, they imply that estrogen is important for attaining peak bone mass in male as well as in female mice.
Vitamin K2 (Menatetrenone) Effectively Prevents Fractures and Sustains Lumbar Bone Mineral Density in Osteoporosis
Authors: Shiraki Masataka , Shiraki Yumiko , Aoki Choju , Miura Masakazu 
Published: April 2006

Abstract
We attempted to investigate whether vitamin K2 (menatetrenone) treatment effectively prevents the incidence of new fractures in osteoporosis. A total of 241 osteoporotic patients were enrolled in a 24-month randomized open label study. The control group (without treatment; n = 121) and the vitamin K2–treated group (n = 120), which received 45 mg/day orally vitamin K2, were followed for lumbar bone mineral density (LBMD; measured by dual-energy X-ray absorptiometry [DXA]) and occurrence of new clinical fractures. Serum level of Glu-osteocalcin (Glu-OC) and menaquinone-4 levels were measured at the end of the follow-up period. Serum level of OC and urinary excretion of deoxypyridinoline (DPD) were measured before and after the treatment. The background data of these two groups were identical. The incidence of clinical fractures during the 2 years of treatment in the control was higher than the vitamin K2–treated group (χ2 = 10.935; p = 0.0273). The percentages of change from the initial value of LBMD at 6, 12, and 24 months after the initiation of the study were −1.8 ± 0.6%, −2.4 ± 0.7%, and −3.3 ± 0.8% for the control group, and 1.4 ± 0.7%, −0.1 ± 0.6%, and −0.5 ± 1.0% for the vitamin K2–treated group, respectively. The changes in LBMD at each time point were significantly different between the control and the treated group (p = 0.0010 for 6 months, p = 0.0153 for 12 months, and p = 0.0339 for 24 months). The serum levels of Glu-OC at the end of the observation period in the control and the treated group were 3.0 ± 0.3 ng/ml and 1.6 ± 0.1 ng/ml, respectively (p &lt; 0.0001), while the serum level of OC measured by the conventional radioimmunoassay (RIA) showed a significant rise (42.4 ± 6.9% from the basal value) in the treated group at 24 months (18.2 ± 6.1% for the controls; p = 0.0081). There was no significant change in urinary DPD excretion in the treated group. These findings suggest that vitamin K2 treatment effectively prevents the occurrence of new fractures, although the vitamin K2–treated group failed to increase in LBMD. Furthermore, vitamin K2 treatment enhances γ-carboxylation of the OC molecule.
Transient Chondrogenic Phase in the Intramembranous Pathway During Normal Skeletal Development
Authors: Nah Hyun-Duck , Pacifici Maurizio , Gerstenfeld Louis C. , Adams Sherrill L. , Kirsch Thorsten 
Published: April 2006

Abstract
Calvarial and facial bones form by intramembranous ossification, in which bone cells arise directly from mesenchyme without an intermediate cartilage anlage. However, a number of studies have reported the emergence of chondrocytes from in vitro calvarial cell or organ cultures and the expression of type II collagen, a cartilage-characteristic marker, in developing calvarial bones. Based on these findings we hypothesized that a covert chondrogenic phase may be an integral part of the normal intramembranous pathway. To test this hypothesis, we analyzed the temporal and spatial expression patterns of cartilage characteristic genes in normal membranous bones from chick embryos at various developmental stages (days 12, 15 and 19). Northern and RNAse protection analyses revealed that embryonic frontal bones expressed not only the type I collagen gene but also a subset of cartilage characteristic genes, types IIA and XI collagen and aggrecan, thus resembling a phenotype of prechondrogenic-condensing mesenchyme. The expression of cartilage-characteristic genes decreased with the progression of bone maturation. Immunohistochemical analyses of developing embryonic chick heads indicated that type II collagen and aggrecan were produced by alkaline phosphatase activity positive cells engaged in early stages of osteogenic differentiation, such as cells in preosteogenic-condensing mesenchyme, the cambium layer of periosteum, the advancing osteogenic front, and osteoid bone. Type IIB and X collagen messenger RNAs (mRNA), markers for mature chondrocytes, were also detected at low levels in calvarial bone but not until late embryonic stages (day 19), indicating that some calvarial cells may undergo overt chondrogenesis. On the basis of our findings, we propose that the normal intramembranous pathway in chicks includes a previously unrecognized transient chondrogenic phase similar to prechondrogenic mesenchyme, and that the cells in this phase retain chondrogenic potential that can be expressed in specific in vitro and in vivo microenvironments.
Comparative Effects of Estrogen and Raloxifene on B Lymphopoiesis and Bone Loss Induced by Sex Steroid Deficiency in Mice
Authors: Onoe Yoshiko , Miyaura Chisato , Ito Masako , Ohta Hiroaki , Nozawa Shiro , Suda Tatsuo 
Published: April 2006

Abstract
Estrogen deficiency caused by ovariectomy (OVX) results in a marked bone loss because of stimulated bone resorption. We have reported that OVX selectively stimulates B lymphopoiesis in mouse bone marrow, which is somehow related to bone resorption. Estrogen prevents both the increased B lymphopoiesis and the bone resorption caused by estrogen deficiency. Raloxifene also has a potent estrogenic activity for bone with minimal estrogenic activity for the uterus. To examine the effects of raloxifene on B lymphopoiesis and bone resorption, OVX mice were given either estrogen or raloxifene subcutaneously for 2–4 weeks using a miniosmotic pump. Reduced uterine weight in OVX mice was restored completely by 17β-estradiol (E2). Some 300-fold higher doses of raloxifene increased uterine weight of OVX mice, but only slightly. The number of B220- positive pre-B cells was increased markedly in bone marrow after OVX. The increased B lymphopoiesis was prevented not only by E2 but by raloxifene. In OVX mice, the trabecular bone volume (BV) of the femoral distal metaphysis was reduced markedly, when measured by microcomputed tomography (μCT) scanning and dual-energy X-ray absorptiometry. Both E2 and raloxifene similarly restored it. Like estrogen deficiency, androgen deficiency induced by orchidectomy (ORX) also resulted in a marked bone loss and increased B lymphopoiesis. Both E2 and raloxifene prevented the changes in ORX mice. These results indicate that both estrogen deficiency and androgen deficiency similarly stimulate B lymphopoiesis in mouse bone marrow, which accompany bone loss. Raloxifene exhibits estrogenic actions in bone and bone marrow to prevent bone loss and regulate B lymphopoiesis without inducing estrogenic action in the uterus.