bluuebunny/crossref_metadata_2025_split huggingface dataset:
A reflection scanning acoustic microscope for bone and bone‐biomaterials interface studies
Authors: Meunier A. , Katz J. L. , Christel P. , Sedel L. 
Published: February 2005

AbstractA relatively simple scanning acoustic microscope (SAM) that operates in the reflection mode has been constructed. The system uses a 20 MHz spherically focused transducer, acting both as transmitter and as detector, to obtain acoustic impedance information on a thin surface layer at a maximum resolution of approximately 100 μm. The specimen is mounted on an X‐Y driving system (precision, 5 μm) under computer control in order to scan a grid of 256 × 256 points across areas ranging from 6.5 to 1300 mm2. An algorithm is used to reference the data against standards; specially developed software provides for pseudo‐color mapping, three‐dimensional images, zooming to 16X magnification, contouring, and single line profiles of the data. The system has been used to determine inhomogeneities in surface acoustic properties of mineralized tissues and implant materials, in many cases as a complement to using ultrasonic wave propagation techniques to measure the bulk anisotropic properties.
Extracellular matrix alterations during endochondral ossification in humans
Authors: Horton William A. , Machado Mirta M. 
Published: February 2005

AbstractImmunohistochemical methods were employed to examine alterations in the cartilage extracellular matrix constituents associated with endochondral ossification in humans. The distributions of chondroitin 4‐ and 6‐ sulfate and keratan sulfate proteoglycan (PG) determinants. cartilage PG link protein. collagen types I and II. and fibronectin were determined in iliac crest growth‐plate specimens using the avidin‐biotin‐horseradish peroxidase system. Collagen type II was distributed throughout the growth plate, providing a framework within which chondrocytes divided and formed clusters of differentiating (hypertrophic) cells. The septa between these clusters and their subchondral extensions into underlying bone trabeculae were rich in PG. PG link protein, and collagen type II and resembled the extracellular matrix of reserve cartilage. The territorial matrix associated with the differentiating cells within the clusters contained reduced amounts of collagen type II, PG link protein, and possibly cartilage PG. Collagen type I and fibronectin were detected within the cytoplasm of the maturing and degenerating cells, and fibronectin localized intensely to the pericellular matrix envelopes of these cells. These alterations presumably facilitate the degradation of the matrix associated with the cell clusters by invading vascular tissue, while the septa. which retain the characteristics of more typical cartilage matrix, are not degraded and firmly anchor the cartilage to the subchondral bone.
Demonstration of type I and type II somatomedin receptors on bovine growth plate chondrocytes
Authors: Trippel S. B. , Chernausek S. D. , Van Wyk J. J. , Moses A. C. , Mankin H. J. 
Published: February 2005

AbstractThe chondrocytes of the epiphyseal growth plate are the presumed target cells for hormones regulating skeletal growth. The somatomedins, a family of low molecular weight peptides, are thought to play a stimulatory role in this regulation. The cellular actions of the somatomedins are themselves determined by binding to specific receptors on target cells. Previous studies have characterized a specific receptor for somatomedin‐C (Sm‐C) or insulin‐like growth factor I (IGF‐I) on bovine growth plate chondrocytes (GPCs). We now report the characterization of a second type of somatomedin receptor on these cells that is more specific for another class of somatomedin represented by multiplication‐stimulating activity (MSA) or rat insulin‐like growth factor II (rIGF‐II). Binding of [125I]MSA/rIGF‐II to isolated GPCs was time dependent and saturable. Unlabeled Mr 7.100 MSA/rIGF‐II and Sm‐C/IGF‐I were approximately equipotent in competing with [125I] MSA/rIGF‐II for binding. while Mr 8,600 MSA/rIGF‐II was an order of magnitude less potent. Low levels of competition by insulin appeared in some studies at concentrations of 10−7 M and higher. suggesting displacement of [125I]MSA/rIGF‐II binding. to the Sm‐C/IGF‐I receptor. In affinity‐labeling studies. [125I]Sm‐C/IGF‐I labeled a complex of Mr >300.000 (unreduced) and of Mr 140.000 (reduced). consistent with a type I somatomedin receptor composed of disulfide‐linked subunits. [125I]MSA/rIGF‐II labeled a Mr 240.000 moiety (unreduced) and Mr 260.000 (reduced). consistent with a type II somatomedin receptor. Both affinity‐labeling and kinetic data revealed cross‐binding of MSA/rIGF‐II and insulin with the type I receptor and of Sm‐C/IGF‐I with the type II receptor. In contrast. the type II receptor did not recognize insulin. These data suggest a complex pattern of graded specificity of these receptors for their ligands. These data are consistent with the hypothesis that IGF‐II as well as Sm‐C/IGF‐I participate in the stimulation of skeletal growth.
Motions and loads within the human pelvis: A biomechanical model study
Authors: Scholten P. J. M. , Schultz A. B. , Luchies C. W. , Miller J. A. A. 
Published: February 2005

AbstractThe pelvis, a major load carrying component of the musculoskeletal system, is sometimes suspected as a site of mechanically provoked low back pain. Thus, studies of its basic biomechanics seem warranted. This study used biomechanical model simulations to examine how pelvic geometry and joint soft tissue properties influence relative motions among its bones and internal loadings of its joints. A biomechanical model of a pelvis was loaded by forces of up to 1000 N and moments of up to 25 Nm. Its resulting motions and joint loadings were determined. The effects on these responses due to pelvic geometry changes of 20% in lengths and 10° in angles, and soft tissue stiffness changes, most of which were 25%, were also examined. For all situations examined, model pelvis relative displacements were at most a few mm, and relative rotations were at most a few degrees. Internal forces and moments were always less than 530 N and 30 Nm, respectively.
The effects of demineralized bone matrix and direct current on an “in vivo” culture of bone marrow cells
Authors: Friedenberg Zachary B. , Brighton Carl T. , Michelson James D. , Bednar John , Schmidt Richard , Brockmeyer Thomas 
Published: February 2005

AbstractBone marrow cells (BMCs) from rabbit femora and tibiae were grown in diffusion chambers implanted in rabbit muscle. At 42 days 80% of the BMC chambers exhibited cartilage formation within them. Demineralized bone matrix added to the marrow cell suspension in the chamber accelerated the appearance and increased the number of chambers with cartilage. Mineralization of the cartilage also occurred earlier in the chambers with bone matrix. In a second experiment, a 5‐μA direct current cathode in the bone marrow chamber increased the number of chambers containing cartilage from 50 to 80% at day 25. Mineralization also occurred earlier in the chambers with direct current.
Nonlinear viscoelastic properties of articular cartilage in shear
Authors: Spirt Adrienne A. , Mak Arthur F. , Wassell Richard P. 
Published: February 2005

AbstractThe strain dependence of the intrinsic viscoelastic properties of the cartilage matrix in shear was investigated. Stress relaxation experiments were performed on bovine articular cartilage at shear strains ranging from approximately 3% to 16%. The tissue was found to exhibit nonlinear strain‐dependent viscoelastic behavior, with the nonlinearity occurring primarily in the short‐time transient during stress relaxation. In addition, the equilibrium stress was found to fit a quadratic relation with strain. This relationship was noted to be nearly linear with strain from 3% to 16%. The instantaneous stress was seen to be highly nonlinear, and followed a cubic relationship with applied shear strain. Fung's quasilinear theory can be used to describe the stress relaxation response over the range of strains examined when a nonlinear regression is performed to determine an “average” normalized relaxation function. Alternately, strain dependence can be incorporated into the model to describe and predict more accurately the strain‐dependent stress relaxation response.
Canine bone blood flow estimated with microspheres
Authors: Li Guoping , Bronk James T. , Kelly Patrick J. 
Published: February 2005

AbstractBlood flow rate in the periosteal and endosteal cortices of the diaphysis of long bones was determined in eight anesthetized adult dogs using the radioactively labeled microsphere method. The flow rate in endosteal and periosteal cortices is not significantly different unless the endosteal cortex contains cancellous bone from the medullary cavity. The highest flow rate is in the ulna, with 6.50 ml/min/100 g for the endosteal cortex and 5.15 ml/min/100 g for the periosteal cortex. The lowest flow rate is in the femur, with 2.89 ml/min/100 g for the endosteal cortex and 2.29 ml/min/100 g for the periosteal cortex. The results of this study indicate that variation of blood flow does exist between bones of dogs. However, the flow rates of individual bone on the left and right sides in the same dog are not significantly different. This indicates that the data are reproducible and reliable, and differences are not an inaccuracy of the radioactively labeled microsphere method. The results also demonstrate that there are no significant differences in bone blood flow as measured with small numbers (fewer than 400 microspheres per sample) and large numbers (more than 400 microspheres per sample) of microspheres. The adequate number of microspheres in each bone sample is 150–250. Therefore, a dose of 0.5 × 106 spheres/kg body weight can be sufficient.
Internal deformations of intact and denucleated human lumbar discs subjected to compression, flexion, and extension loads
Authors: Seroussi Richard E. , Krag Martin H. , Muller David L. , Pope Malcolm H. 
Published: February 2005

AbstractThree rows of six evenly spaced 0.5 mm metal beads were implanted midsagittally into the discs of ten L4–5 human lumbar motion segments. The intradiscal bead displacements in response to compression, flexion, and extension loads were obtained by digitizing the bead positions from sagittal plane radiographs taken before and during the load application. Each disc was denucleated and the loading process was repeated. For the intact discs, in compression, the intradiscal bead displacements were predominantly anterior. In flexion, the beads in the center of the disc moved posteriorly whereas the beads closer to the periphery of the disc moved anteriorly. In extension, the central beads moved anteriorly and the beads closer to the periphery of the disc moved posteriorly. After denucleation, the bead displacements for compression and flexion implied an inward bulging of the inner wall of the annulus, despite outward bulging of the disc surface. We hypothesize that the inward bulging causes radial tensile stresses within the disc, leading to disruption of adjacent layers of annulus.
Tibial anatomy and functional axes
Authors: Yoshioka Yuki , Siu David W. , Scudamore R. Allan , Cooke T. Derek V. 
Published: February 2005

AbstractArticular geometry of the tibia has been studied in relation to the functional axis and extra‐articular bone landmarks, using a Cartesian coordinate system. Thirty‐one cadaver limbs were used, 26 of them paired. The donor age range was 61 to 89 years (17 females, 14 males), none of whom showed evidence of significant arthritic deterioration. Most linear parameters were greater in males than females (p < 0.005), and correlations between these parameters were noted, e.g., tibial length versus plateau width (r = 0.7, p < 0.01) with both genders combined. Gender differences occurred in only two of the angular parameters—tibial torsion (p < 0.025) and foot rotation (p < 0.005). For the latter, mean rotation was internal (−5°) for males, and external (11°) for females. No correlations between angular parameters were found. In the paired limbs, there was asymmetrical distribution of just two parameters—varus tilt of the tibial plateau margins (p < 0.005) and lateral deviation of the tuberosity (p < 0.025). The data complement a previous report on the femur. These studies are relevant to the kinematics of the lower limb, design and sizing of resurfacing components, and possibly to the pathogenesis of osteoarthritis.
Ingredients of a successful grant application to the national institutes of health
Authors: Gordon Stephen L. 
Published: February 2005

AbstractMany factors determine the scientific merit of an NIH research grant application. This paper is intended to help optimize the organization and logical development of investigators' research ideas so that grant applications will be evaluated by the reviewers in as favorable a light as possible. The ingredients of a successful grant application are good ideas, good science, and a good application. The research should be based on a significant hypothesis and, if possible, oriented towards uncovering an important biological mechanism. Specific methods should be directly related to each aim of the project. Likewise, the specific aims should be related to each hypothesis. All aspects of the application should be clear and focused. It is best to define all assumptions, limitations, and alternative approaches. In general, the best philosophy is for the applicant to address all possible problems before the reviewers do.
Articular cartilage and intervertebral disc proteoglycans differ in structure: An electron microscopic study
Authors: Buckwalter Joseph A. , Smith K. C. , Kazarien L. E. , Rosenberg Lawrence C. , Ungar Robin 
Published: February 2005

AbstractArticular cartilage and the intervertebral disc tissues have different material and biological properties and different patterns of aging and degeneration. To determine if the proteoglycans of these tissues differ in structure, we used the electron microscopic monolayer technique to compare baboon articular cartilage proteoglycans with baboon annulus fibrosus, transition zone, and nucleus pulposus proteoglycans. Intervertebral disc and articular cartilage porteoglycans differed signficantly. Articular cartilage contained large proteoglycan aggregates formed from hyaluronic acid central filaments, multiple monomers, and large nonaggregated monomers. These molecules were identical to those of nasal cartilage, growth plate cartilage, chondrosarcomas, or menisci. In contrast, the intervertebral disc tissues contained only nonaggregated proteoglycan monomers and clusters of monomers without apparent central filaments. Intervertebral disc nonaggregated monomers were shorter and more variable in length than those from articular cartilage, and nucleus pulposus nonaggregated monomers were even shorter and more variable in length than transition zone and annulus fibrosus monomers. These observations suggest that significant differences in proteoglycan metabolism exist between articular cartilage and intervertebral disc.
Omental angiogenic lipid fraction and bone repair. An experimental study in the rat
Authors: Nottebaert M. , Lane J. M. , Juhn A. , Burstein A. , Schneider R. , Klein Ch. , Sinn R. S. , Dowling Ch. , Cornell Ch. , Catsimpoolas N. 
Published: February 2005

AbstractA lipid material extracted from the omentum has previously been shown to contain a potent angiogenetic activator (20), capable of creating intense vasoproliferation in traumatized tissues (19). This study was undertaken to analyze the efficacy of local administration of this omental lipid fraction on osseous vascularization and bone repair. An osteoperiosteal segmental femoral defect in the rat was replaced by a demineralized allogenic bone graft exposed to continuous local delivery of omental lipid via an implanted miniosmotic pump. Saline solution delivered in the same way served as a control. Neovascularization and bone formation in the transplant were quantitatively evaluated by means of dynamic radioisotopic bone imaging, radiographic photodensitometry, microangiography, and biomechanical testing. Compared with the control group, the omental lipid angiogenic fraction–treated specimens showed an 80% overall increase (p < 0.001) in bone density as well as a twofold increase (p < 0.001) in regional blood perfusion, maximal at 2 weeks following surgery. At 12 weeks, biomechanical testing demonstrated significantly higher union rate (p < 0.05) and strength (p < 0.01) in the treated specimens as compared with the controls. These data demonstrate that the omental lipid fraction factor has potent angiogenic properties that enhance bone blood perfusion and bone regeneration.
The effect of radiation on the fracture repair process. A biomechanical evaluation of a closed fracture in a rat model
Authors: Markbreiter Lance A. , Pelker Richard R. , Friedlaender Gary E. , Peschel R. , Panjabi M. M. 
Published: February 2005

AbstractThe effects of a single dose of irradiation on the biomechanical parameters of the fracture healing process were studied in a rat model. Intramedullary pinning was performed before production of a closed femoral midshaft fracture. The experimental group was exposed to 900 rad 3 days after fracture and was compared with a control group with a similar fracture that received no irradiation. Animals were killed at intervals ranging from 2–16 weeks after surgery and the bones were tested until failure in torsion. In the irradiated groups, a delay of 4 weeks was noted in the biomechanical parameters associated with fracture healing (torque to failure, torsional stiffness, angle to failure, and biomechanical stage). Despite this delay in the normal temporal progression, the staging and stiffness approached normal controls within an 8‐week period. However, the torque to failure remained below normal levels at the conclusion of this study. These results differ from a previous study using an open fracture model.
Low body weight as a risk factor for hip fracture in both black and white women
Authors: Pruzansky Mark E. , Turano Michael , Luckey Marjorie , Senie Ruby 
Published: February 2005

AbstractA lower incidence of hip fracture in black women has been reported by several studies. The most frequently proposed explanations for this phenomenon have included a genetically greater bone mass, better preservation of bone due to the fact that certain populations of black women perform more physical labor, and the impact of other unidentified environmental and/or life‐style factors. This retrospective study demonstrates that low body weight is as significant a risk factor for hip fracture in black women as it is in white women. Coupled with the known higher prevalence of obesity in the older black female population, the findings of this study suggest that differences in body weight may be a significant and possibly sufficient explanation for the lower incidence of hip fracture in black women.
Effects of chondroitinase‐ABC on proteoglycans and swelling properties of fibrocartilage in bovine flexor tendon
Authors: Koob Thomas J. 
Published: February 2005

AbstractFibrocartilaginous regions of bovine deep flexor tendon were treated with chondroitinase‐ABC and trypsin in order to extract proteoglycans from the extracellular matrix and thereby investigate the contribution of proteoglycan and collagen organization to tissue material properties. Chondroitinase‐ABC digestion of tendon specimens for 24 h resulted in extraction of 60% of tissue glycosaminoglycan and leaching of the degraded large proteoglycan from the tissue residue. The totally degraded core protein of the small dermatan sulfate proteoglycan remained with the tissue residue, indicating that it is specifically associated with the tissue residue and that this association is not dependent on the glycosaminoglycan chains. Treatment of residues with trypsin after chondroitinase‐ABC digestion depleted the specimens of proteoglycan. Bulk swelling tests on enzyme‐extracted specimens showed that the distinct swelling properties of the fibrocartilaginous regions of the distal flexor tendon could be partially accounted for by elevated levels of proteoglycan. Swelling tests also showed that the distinct collagen organization of this region contributes significantly to the tissue's material properties. These results suggest that the fibrocartilaginous organization and composition of the articulating layer of distal tendon are adapted for mechanical requirements unique to this site, which receives compressive and frictional loads in addition to tensile loads.
Neutral metalloprotease from tendons
Authors: Piening C. , Riederer‐Henderson M. A. 
Published: February 2005

AbstractTendon repair following trauma, rupture, or surgery involves both synthesis and degradation of collagen in order to reweave new collagen bundles in with the old. Using an in situ assay on polyacrylamide gels containing gelatin, we have identified protease activity from tendon tissue and from tendon cells in culture. A population of synovial cells from the epitenon surrounding the tendon as well as the tendon fibroblasts themselves were examined. The cells and the conditioned medium from both cell populations exhibited a major band of gelatin‐degrading activity at 70 kdaltons and a minor band of activity at 60 kdaltons. When preparations were reacted with p‐aminophenylmercuric acetate (APMA) before electrophoresis, a third band appeared at 63 kdaltons. The main band at 70 kdaltons comigrated with a [35S]methionine‐radiolabeled protein band. Inhibitor and pH studies identified the enzymes as neutral metalloproteases requiring disulfide bonds for activity. No proteolytic activity was detected on casein‐containing gels, ruling out the presence of stromelysin. Since electrophoresis in the presence of SDS would separate the metalloprotease from the smaller molecular weight inhibitor (TIMP), these in situ assays provide a sensitive screening system for gelatindegrading enzymes present in tendon without prior removal of TIMP.