bluuebunny/crossref_metadata_2025_split huggingface dataset:
Superoxide dismutase and catalase activities in the growth cartilage: Relationship between oxidoreductase activity and chondrocyte maturation
Authors: Matsumoto H. , Silverton S.F. , Debolt K. , Dr. Shapiro I.M. 
Published: February 2010

Abstract
Superoxide dismutase (SOD) and catalase are enzymes that protect cells from radical attack. Catalase disproportionates hydrogen peroxide, and SOD is an oxidoreductase that serves to dismutate the superoxide anion. The objective of this communication was to measure the activity of these disproportionating enzymes in the chick tibial growth cartilage and to relate enzyme activity to chondrocyte maturation and tissue calcification. Analytic techniques were optimized for the measurement of both enzymes; particular care was taken to ensure that the values obtained were due to SOD and catalase, not to the presence of other oxidases or contaminants. Catalase and SOD had similar profiles of activity in cartilage. For both enzymes, the highest levels of activity were observed in premineralized cartilage; as chondrocytes matured there was a progressive decrease in the activity of SOD and catalase. Comparison of chondrocyte SOD activity with nonmineralizing tissues indicated that the activity of cultured cartilage cells was low. We also measured the SOD activity of avascular chondrodystrophic cartilage and found it to be less than that of proliferating cartilage. When cartilage was electrofocused, three SOD isozymes were detected. The pI of the major isozyme corresponded to the copper-zinc isoform. We suggest that the observed changes in enzymatic activity are dependent on a number of cartilage-specific factors that include the vascular supply, the local production of oxygen radicals by chondrocytes, and the oxidative state of the tissue.
Automated comparison of dual-photon absorptiometric studies of the lumbar spine
Authors: Verheij Luis F. , Blokland Jacobus A. K. , Papapoulos Socrates E. , Bijvoet Olav L. M. , Pauwels Ernest K. J. 
Published: February 2010

Abstract
An automated image comparison procedure was developed to optimize the precision of bone mineral density measurements by dual-photon absorptiometry. Changed acquisition conditions cause differences between two images to be compared. Alignment of one image with respect to the other is performed by a transformation that involves a rotation, a horizontal or vertical shift, and a correction for the soft tissue level. The best possible transformation is found in a stepwise search, guided by initial estimations of its parameters. After optimum transformation of one image, the region of interest of the other image is applied to both of them. Duplicate measurements of 9 patients and 15 normal subjects were performed; automated analysis yielded improved precision with respect to manual analysis. The coefficient of variation (CV) was also computed. The CV for automated analysis was 2.00% for patients and 1.04% for normal subjects compared to 3.55 and 1.93%, respectively, for manual analysis. For phantoms, the precision was 2.67% for manual analysis and 0.49% for automated analysis.
Cortical osteoclasts are less sensitive to etidronate than trabecular osteoclasts
Authors: Chappard Daniel , Petitjean Muriel , Alexandre Christian , Vico Laurence , Minaire Pierre , Riffat Georges 
Published: February 2010

Abstract
Acute osteoporosis after spinal cord injury is related to an early increase in osteoclastic resorption. Healthy subjects subjected to bed rest similarly increase their osteoclast number in trabecular bone. Bisphosphonates possess a highly antiosteoclastic activity. The effects of a 120 day bed rest period, with or without etidronate therapy on cortical bone were measured in 15 subjects. Cortical thickness and cortical porosity were measured on transiliac bone biopsies taken before and after the bed rest period. Osteoclasts were detected histo-chemically and were counted with a semiautomatic image analyzer. Cortical thickness, cortical porosity, and cortical osteoclast number were not significantly modified in subjects submitted to bed rest alone. In the etidronate-treated patients, cortical bone mass parameters were also found to be unaffected, but the most striking feature was that the osteoclast number was unchanged. Trabecular osteoclasts, on the contrary, were increased in the untreated subjects (+95.2%) but decreased in the treated subjects (-78%). Bone cells may have heterogeneous responses according to their trabecular or cortical location. Cortical osteoclasts seem to be unaffected by etidronate therapy.
Comparison of total-body measurements by dual-energy x-ray absorptiometry and dual-photon absorptiometry
Authors: Prof. Nuti Ranuccio , Martini G. , Righi G. , Frediani B. , Turchetti V. 
Published: February 2010

Abstract
Both dual-photon absorptiometry (DPA) using 153Gd and dual-energy x-ray absorptiometry (DEXA) can be used for measurement of bone mineral content (BMC) and bone mineral density (BMD) of the total skeleton and its seven major regions. The short-term precision (coefficient of variation, CV) of DEXA for total-body BMD using the medium (20 minute) and fast (10 minute) speeds was 0.34 and 0.68% in 5 normal subjects; the corresponding CV in 5 osteoporotic females were 0.70 and 1.04%. The CV for BMD using DPA was 0.82% in 8 normal subjects and 0.70% in 12 osteoporotic patients. The CV for regional BMD using DPA was similar to fast-speed DEXA, without significant differences (p NS); precision with medium-speed DEXA was superior to DPA, and the differences were statistically significant (p &lt; 0.05) for head, spine, trunk, ribs, and pelvis. Total-body measurements using both DPA and DEXA were done on 99 subjects (84 females and 15 males). Significant correlations (r = 0.98; p &lt; 0.001) were found between DEXA and DPA measurements of both BMC and BMD. There were also significant correlations (r = 0.94–0.98; p &lt; 0.001) between DEXA and DPA measurements of anatomic regions (head, trunk, spine, pelvis, ribs, arms, and legs). DPA and DEXA results for BMD of total skeleton, ribs, pelvis, and legs were similar (p NS), and statistically significant differences were found in head, spine, and arm measurements (p &lt; 0.01, p &lt; 0.01, and p &lt; 0.05, respectively); regression equations allowed adjustment of DEXA values in patients already measured with the earlier DPA method.
Purinergic regulation of cytosolic calcium and phosphoinositide metabolism in rat osteoblast-like osteosarcoma cells
Authors: Kumagai Hiromichi , Sacktor Bertram , Filburn Charles R. 
Published: February 2010

Abstract
We have shown that ATP increases cytosolic Ca2+ in UMR-106 cells through P2-purinergic receptor stimulation (Calcif Tissue Int 45:251-254). This response was further characterized using cells loaded with indo-1/AM or prelabeled with [3H]inositol. ATP elicited a rapid transient increase in Ca2+ from 148 to 540 nM, followed by a biphasic decline (first rapid and then slower) to basal within 1 minute and then a late slow rise to 200 nM by 4 minutes. ADP also elicited a rapid transient increase, but this was followed by a second smaller transient and a later, slow increase above basal Ca2+. These transient increases in Ca2+ induced by ATP and ADP were dose dependent, detected at 10−6 M ATP and 10−7 M ADP, and saturated at 10−4 M with both nucleotides. The maximum increase in Ca2+ was 20% greater with ATP than ADP. EGTA chelation of extracellular Ca2+ abolished the biphasicity of the ATP-induced Ca2+ transient, the second ADP-induced transient, and all late slower increases in Ca2+. Desmethoxyverapamil pretreatment attenuated the biphasicity of the ATP-induced transient and the second peak elicited by ADP. Elevated extracellular Ca2+ (5 mM) prevented the return to the basal level that normally follows the ATP-induced Ca2+ transient and amplified the sustained increase in Ca2+ but had little effect on the response to ADP. IP3 and IP4 increased rapidly after addition of ATP, with I(1,4,5)P3 increasing before I(1,3,4)P3. These data indicate that P2-purinergic stimulation of UMR-106 cells causes three consecutive responses in cytosolic Ca2+: (1) a transient increase due to IP3-mediated mobilization of intracellular Ca2+; (2) a transient increase due in part to influx, probably associated with a Ca2+ channel; and (3) a later sustained increase that requires extracellular calcium.
Structural and geometric changes in iliac bone: Relationship to normal aging and osteoporosis
Authors: Foldes J. , Parfitt A.M. , Shih M.S. , Rao D.S. , Kleerekoper M. 
Published: February 2010

Abstract
We Measured Indices Of Bone Volume (Cancellous And Cortical) And Bone Surface (Cancellous, Endocortical, And Intracortical) In Intact, Full-Thickness Transiliac Bone Biopsies Obtained From 47 Healthy White Women (23 Premenopausal And 24 Postmenopausal) And 82 Patients With Postmenopausal Osteoporosis. In The Normal Subjects There Was The Expected Loss Of Cancellous Bone With Age, Best Shown By A Reduction In Bone Surface/Tissue Volume, But No Fall In Cortical Thickness With Age Despite A Significant Reduction In Forearm Bone Density Measured By Single-Photon Absorptiometry. Bone Surface/Bone Volume Was About Four Times Higher In Cancellous Than In Cortical Bone, And Cancellous Bone Contributed About One-Third Of The Total Bone Volume And About Two-Thirds Of The Bone Surface When Related To The Core Volume Referent. In The Osteoporotic Patients, Core Width, An Index Of Iliac Bone Thickness At The Biopsy Site, Was Reduced By 10%, But We Could Not Determine Whether This Was The Result Of Compaction Of The Core Or Of Bone Slenderness. All Indices Of Bone Volume, Cortical As Well As Cancellous, Were Significantly Smaller, As Were The Values For Forearm Bone Densitometry; The Relative Deficits At Different Sites Depended On Whether They Were Expressed As Percentages Or As Z Scores. Bone Surface/Bone Volume Was Increased In Both Cancellous And Cortical Bone, But Bone Surface/Tissue Volume Was Reduced In Cancellous Bone And Increased In Cortical Bone. The Proportions Of Total Bone Volume And Surface Contributed By Cancellous And Cortical Bone Were Almost The Same As In Normal Postmenopausal Women. We Reached The Following Conclusions: (1) Age-Related Bone Loss In Normal Subjects Is More Difficult To Detect By Histomorphometry Than By Densitometry. (2) Cortical Bone Loss May Be Slower In The Axial Than In The Appendicular Skeleton. (3) The Amount Of Bone Is Reduced At All Sites In Osteoporotic Patients; The Deficit Is Not Necessarily Greater In Cancellous Than In Cortical Bone But May Be Greater In The Axial Than In The Appendicular Skeleton. (4) Cortical Bone Contributes Relatively Less Volume And Relatively More Surface In The Axial Then In The Appendicular Skeleton. (5) Depending On The Location And The Referent, Bone Surface And Volume May Change In The Same Or In Opposite Directions, With Consequences For The Time Course Of Bone Loss And The Relationships Between Biochemical And Histologic Indices Of Bone Remodeling.
Calcium-deficient diet in ovariectomized dogs limits the effects of 17β-estradiol and nandrolone decanoate on bone
Authors: Dr. Geusens P. , Schot L.P.C. , Nijs J. , Dequeker J. 
Published: February 2010

Abstract
Postmortem measurements by dual-photon absorptiometry of the femur and the second lumbar vertebra in adult dogs indicated bone loss after ovariectomy, which was more pronounced when calcium-deficient diet was given in ovariectomized dogs. This bone loss was nonhomogeneous throughout the femur. Ovariectomy resulted in trabecular and cortical bone loss, and additional calcium-deficient diet resulted in a further highly significant trabecular bone loss at the proximal epiphysis of the femur and in the vertebra. This bone loss was presumably the result of increased bone turnover, as reflected by the highly significant increase in serum alkaline phosphatase. Estrogens could only partially prevent the bone loss induced by calcium deficiency after ovariectomy, and nandrolone decanoate was not effective. We conclude that (1) ovariectomy results in bone loss in adult dogs, (2) this bone loss is more pronounced after calcium-deficient diet, (3) calcium deficiency could be a limiting factor for the preventive effect of estrogens and nandrolone decanoate, and (4) dual-photon absorptiometry allows the evaluation of nonhomogeneous bone loss throughout excised bones.
Risk factors for hip fractures in men: A preliminary study
Authors: Grisso Jeane Ann , Chiu Grace Y. , Maislin Greg , Steinmann William C. , Portale Julia 
Published: February 2010

Abstract
Although hip fracture rates are higher in women than in men, for older men the lifetime risk of fractures of the femur is substantial. Very little is known about risk factors for hip fracture in men. A preliminary case control study was conducted comparing the medical charts of men with first hip fractures with two sets of age-matched controls. The major risk factors for hip fracture that emerged were preadmission ambulatory problems, confusion, heavy alcohol use, and low body mass. Although this study is limited to a medical chart review in a veteran population, these results confirm some of the known associations for hip fracture in women. Further studies in men are recommended.
Bone cell culture in a three-dimensional polymer bead stabilizes the differentiated phenotype and provides evidence that osteoblastic cells synthesize type III collagen and fibronectin
Authors: Majmudar Gopa , Bole David , Goldstein Steven A. , Bonadio Jeffrey 
Published: February 2010

Abstract
We report a novel method to culture chick embryo osteoblasts in vitro. Primary cells were grown from explants of calvaria and then cultured within alginate polymer beads. Enriched cultures of primary osteoblasts were obtained because these cells grow readily within alginate beads but other cell types present in the initial outgrowth from calvarial fragments, such as fibroblasts, do not. A reproducible bone cell phenotype was observed in calvarial cells cultured in the alginate polymer for as long as 8 months. Alginate is a uronic acid monomer that reversibly polymerizes based on the presence or absence of divalent cations. Osteoblasts derived from the alginate beads elaborated and mineralized an extracellular matrix in vitro that contained fibronectin, type III collagen, and type I collagen. The synthesis and deposition of these matrix molecules was also demonstrated in the chick embryo calvaria in vivo. Together, these in vitro and in vivo observations provide the first evidence that type III collagen and fibronectin colocalize with type I collagen during the development of avian membranous bone. They also indicate that the phenotype of chick embryo osteoblasts can be expanded to include the synthesis of fibronectin and type III collagen.
Inhibition of parathyroid hormone secretion correlates with increased incorporation of 32P into phosphatidylinositol and lysophosphatidylinositol
Authors: Bajpai Sarita , Kraft Kelly , Dr. Hamilton James W. 
Published: February 2010

Abstract
We have studied the incorporation of radioactive P (32P) into lipids of bovine parathyroid tissue under conditions of stimulated and inhibited hormone secretion. Utilizing low (0.5 mM) and high (3.0 mM) concentrations of calcium to regulate parathyroid hormone secretion, we initially found that the labeling of the cellular phospholipids with 32P was greater in those tissues incubated in high-calcium medium. Thin-layer chromatography of lipid extracts prepared from tissue incubated in either low- or high-calcium media revealed that the increased incorporation of 32P (high or low) was localized primarily to two phospholipids. To determine whether the increases were due directly to the different calcium concentrations, the experiments were performed in media containing normal calcium concentrations (1.25 mM) and low (0.5) or high (3.0) magnesium concentrations to modulate hormone secretion. The results were identical to those obtained using low and high calcium, indicating that the increased 32P incorporation was not an effect of high calcium but rather correlated with the inhibition of hormone secretion. The use of other secretagogues confirmed this correlation. The identity of the two phospholipids was established, by two-dimensional thin-layer chromatography, to be phosphatidylinositol (PI) and lysophosphatidylinositol (LPI). The correlation of increased 32P incorporation with inhibition of secretion led us next to examine isolated secretory granules from tissues exposed to either high-or low-calcium conditions. Thin-layer chromatography of granule lipid extracts yielded chromatograms containing PI and LPI, and the radioactivity of each was greater in the high-calcium sample than in the low-calcium sample. Our data suggest that a pathway for the synthesis and/or recycling of PI and LPI is present in secretory granules. Taken together, our observations suggest that phosphatidylinositol and lysophosphatidylinositol may play a role, either directly or indirectly, in the secretory pathway.
Relationship between the number of resorbing cells and the amount resorbed in metabolic bone disorders
Authors: Cohen-Solal Martine , Morieux Caroline , Dr. de Vernejoul Marie-Christine 
Published: February 2010

Abstract
The relationship between bone-resorbing cells, assessed by the presence of tartrate-resistant acid phosphatases (TRAP) and morphologic indices of bone resorption, was determined in 29 osteoporotic patients (14 postmenopausal females and 15 males) and 15 dialyzed patients. The number of TRAP-positive cells per unit of cancellous bone area (N.Oc/B.Ar) was higher in dialyzed patients than in those with osteoporosis (16.8 (pminus) 15.3 versus 4.95 (pminus) 2.86, p &lt; 0.05). The amount of bone resorbed at the basic multicellular unit level was estimated by calculating eroded area containing TRAP cells per bone area (E.Ar+/BA). This novel parameter was similar in dialyzed and in osteoporotic patients (41,700 (pminus) 28,400 versus 32,300 (pminus) 24,600). In contrast, trabecular spacing (Tb.Sp) was identical in both metabolic bone diseases. Trabecular width (169 (pminus) 38 versus 127 (pminus) 32 (mu)m, p &lt; 0.05) and bone area were higher in dialyzed than in osteoporotic patients. N.Oc/B.Ar was significantly related to E.Ar+/BA in dialyzed (r = 0.76, p &lt; 0.05) but not in osteoporotic patients. Tb.Sp was significantly correlated to N.Oc/B.Ar and to the number of TRAP-positive cell nuclei per B.Ar (r = 0.44, p &lt; 0.05) in osteoporotic but not in dialyzed patients. This last result shows that in overt osteoporosis with thin trabeculae, trabecular spacing is related to the number of resorbing cells. In contrast, the spacing of thick trabeculae in dialysis osteodystrophy is not dependent on the number of osteoclasts.
Effects of fixation and demineralization on the retention of bone phosphoprotein and other matrix components as evaluated by biochemical analyses and quantitative immunocytochemistry
Authors: Dr. McKee M.D. , Nanci A. , Landis W.J. , Gotoh Y. , Gerstenfeld L.C. , Glimcher M.J. 
Published: February 2010

Abstract
Aqueous tissue processing and demineralization procedures may adversely affect the inorganic mineral phase of a calcified sample and, where mineral and organic constituents interact, may consequently also indirectly alter organic matrix ultrastructure and distribution. In the present work, the effects of demineralization have been investigated on the retention in chicken bone of two phosphoamino acids, O-phosphoserine and O-phosphothreonine, found in bone phosphoproteins proposed to be important in vertebrate mineralization and, more specifically, on the retention and distribution of a 66 kD bone phosphoprotein (66 kD BPP, osteopontin) also implicated in the calcification process. In tibiae fixed initially with 1% glutaraldehyde and then demineralized in 0.5 N HCl, 0.5 N acetic acid, or 0.1 M EDTA (all containing 1% glutaraldehyde), amino acid analyses and quantitative immunocytochemistry revealed that the phosphoamino acid content and the distribution of the 66 kD BPP were essentially the same as in fixed undemineralized controls. However, demineralization slightly altered the ultrastructural appearance of immunolabeled, electron-dense patches of organic material in the bone matrix. In unfixed bone demineralized with any of these acids, there was a substantial loss of phosphoamino acids and the 66 kD BPP from the bone matrix. The relative ability of these acids to extract phosphoproteins from unfixed bone was found to decrease in the order EDTA &gt; HCl &gt; acetic acid. These results emphasize the differential effects on structural components of various demineralization and extraction procedures for biochemical and immunocytochemical studies of biologic tissues. Furthermore, they demonstrate that initial fixation with glutaraldehyde retains phosphoproteins in bone, with or without demineralization, while being adequate for immunocytochemical localization of certain bone matrix proteins and that an understanding of the action of specimen preparation on organic constituents (as well as inorganic components) is essential for accurately describing ultrastructural matrix-mineral relationships.
Parathyroid hormone-related protein inhibits stimulated uterine contraction in vitro
Authors: Dr. Shew Ronald L. , Yee John A. , Kliewer Douglas B. , Keflemariam Yodit J. , McNeill Daniel L. 
Published: February 2010

AbstractThe effect of parathyroid hormone-related protein (PTHrP) fragments 1–34, 38–64, and 67–86 on acetylcho-line-stimulated rat uterine contraction was examined in vitro. In addition, the possibility that PTHrP-(38–64) or (67–86) influenced relaxation caused by PTHrP-(1–34) was also investigated. Contraction of uterine horns was stimulated with 10−6 or 10−5 M acetylcholine. PTHrP-(1–34) reduced the magnitude of acetylcho-line-stimulated uterine contraction. This effect was dose related over a concentration range of 10−9–10−6 M. Neither PTHrP-(38–64) or PTHrP-(67–86) at concentrations of 10−8–10−6 M affected uterine contraction stimulated by 10−6 M acetylcholine. These fragments did not affect the relaxation caused by 10−7 M PTHrP-(1–34). These results demonstrate that (1) PTHrP-(1–34) at 10−6 M influences contraction of the rat myometrium and (2) the muscle relaxant activity of PTHrP is associated with the first 34 N-terminal amino acids.
In vivo induction of bone by recombinant human transforming growth factor β1
Authors: Beck L. Steven , Ammann Arthur J. , Aufdemorte Thomas B. , Deguzman Leo , Xu Yvette , Lee Wyne P. , McFatridge Lorrie A. , Chen Theresa L. 
Published: February 2010

Abstract
A single application of recombinant human transforming growth factor β1 (rhTGF-β1) adjacent to cartilage was found to induce bone formation in rabbit ear full-thickness skin wounds. At doses that optimally promote soft tissue healing, 25–100 ng rhTGF-β1 per wound caused osseous tissue formation starting 21 days after wounding to reach a peak incidence and area of bone formation at day 42. Bone formation was followed by active remodeling, resulting in lower incidence and area of bone formation at days 56 and 70. The early phase of bone formation was located overlying the cartilage and involved perichondrial cells that appeared to differentiate directly into osteoblasts forming bone matrix without a cartilage precursor. Cartilage was replaced with bone at later time points. rhTGF-β1 was able to increase the ratio of osteoblasts to osteoclasts lining the trabecular surface of bone and thus increase the net amount of bone formation. The present studies suggest a potential therapeutic role for rhTGF-β1 in hard tissue repair.