bluuebunny/crossref_metadata_2025_split huggingface dataset:
In situ calibration of miniature sensors implanted into the anterior cruciate ligament. Part II: Force probe measurements
Authors: Markolf Keith L. , Willems Matthew J. , Jackson Steven R. , Finerman Gerald A. M. 
Published: February 2005

AbstractThe arthroscopically implantable force probe transducer, which measures the effects of local ligament fiber tension, was inserted into the anteromedial band of the anterior cruciate ligament after measurements with the differential variable reluctance transducer were completed in Part I of this study. The overall goals in Part II remained the same, with additional experiments included to determine the sensitivity of output voltage from the transducer to medial‐lateral placement of the device within the anteromedial band and to depth of placement within a given insertion hole. Calibration curves of output voltage from the arthroscopically implantable force probe transducer versus resultant force in the ligament were generated during a separate series of knee‐loading experiments identical to those performed in Part I. The output voltage for a given probe placement was highly sensitive to the depth of implantation into the anteromedial band. When the probe was completely buried within the ligament, voltage outputs were often sporadic or absent even though surface fibers had clearly developed tension. When the probe was only partially inserted into the hole, such that the end of the probe was slightly proud to the surface, voltage output was significantly, higher as the device measured tension in the superficial fibers. Voltage outputs for proud placement were always significantly higher than corresponding voltages for deep placements for all test conditions. With proud placements, voltage outputs were not sensitive to small deviations in medial‐lateral position within the anteromedial band. Mean coefficients of variation for output voltage (four repeated placements of the probe into the same central hole) ranged from 0.156 to 0.359 (deep and proud insertions). Output voltage from the probe generally followed the pattern of resultant force in the ligament during passive knee extension. For anterior tibial loading, the contribution of deep fibers to resultant force did not depend on the knee flexion angle at which the test was conducted; the contribution of superficial fibers was greatest beyond 45° of flexion and least at full extension. The contributions of the anteromedial band to resultant force in the ligament were not significantly different between the three modes of loading (anterior tibial force, internal tibia torque, and varus moment) at either 0 or 10° of flexion; this was true for both superficial and deep fibers. We found it necessary to secure the probe within the insertion site using a suture (for both deep and proud placements) to obtain repeatable readings. Puncturing the anteromedial band clearly produced tissue damage; the insertion hole often produced a permanent plane of cleavage in the anteromedial band. However, this tissue damage did not alter the overall ability of the ligament to generate resultant force.
Histochemical and molecular analyses of distraction osteogenesis in a mouse model
Authors: Tay B. K‐B. , Le A. X. , Gould S. E. , Helms J. A. 
Published: February 2005

AbstractA tibial lengthening scheme in the mouse was used to study the molecular and cellular events regulating tissue regeneration during distraction osteogenesis. Here, we report on the surgical technique and frame design and describe the histochemical and molecular aspects of distraction during different phases of treatment. A total of 26 mice were used in this study. The treatment protocol was divided into a latency period of 7 days, a phase of active distraction that lasted 10 days with a distraction rate of 0.42 mm/day, and a maturation phase of 9 days. During latency, the distraction site resembled a stabilized fracture callus bn both a histochemical and a molecular level. During active distraction, the gap was characterized by a central fibrous interzone bordered by primary matrix fronts, regenerate bone aligned with the distraction force, parallel columns of vascular sinusoids, and a medullary cavity. Alkaline phosphatase activity was detectedin the endosteal and periosteal surfaces of the bone ends. Tartrate resistant acid phosphatase staining revealed that osteoclasts remodeled the bone regenerate as it formed. Collagen type I was expressed in the periosteum and the primary matrix front during distraction, whereas collagen type‐II transcripts were localizedto discrete regions on the periosteal surfaces, immediately adjacent to the osteotomy ends. Collagen type‐II transcripts were not detected in the fibrous interzone. During the maturation phase, cells within the fibrous interzone expressed collagen type I and exhibited abundant alkaline phosphatase activity, suggesting that they had begun to terminally differentiate. Collectively, these data demonstrate the utility of a mouse model to study the molecular and cellular bases for the regeneration and remodeling of tissue.
Publication rate of abstracts presented at the annual meeting of the orthopaedic research society
Authors: Daluiski Aaron , Kuhns Craig A. , Jackson Kent R. , Lieberman Jay R. 
Published: February 2005

AbstractAlthough the timely conveyance of information at national meetings like those of the Orthopaedic Research Society is critical to the dissemination of new scientific research, the ultimate goal of most researchers is to publish work in peer‐reviewed journals referenced in Medline. All of the abstracts that were presented at the podium at the 1991. 1992. and 1993 annual meetings of the Orthopaedic Research Society and printed in the appropriate yearly transactions were included in this study (n = 888, 296 per year). A detailed computerized Medline search of each author on the abstract and the appropriate keywords from the title was performed until a publication was found; otherwise, the abstract was excluded. The database was searched through June 30. 1997. A total of 463 (52%) of the abstracts were published by July 1, 1997. The percentages for each individual year were similar: 148 (50%) were published in 1991,162 (55%) in 1992, and 153 (52%) in 1993. Publication of the majority of these papers (93.1%, 431 of 463) occurred within 4 years of the respective meeting. The Journal of Orthopaedic Research published the majority of these papers (17.5%), followed by The Journal of Bone and Joint Surgery (American), the Journal of Biomechanics, Clinical Orthopaedics and Related Research, and Spine (each 5.2%). No significant differences in the rate of publication were observed between papers of 10 broad subject categories (p = 0.103). These results are similar to those from other basic science meetings and to the recently reported results for the annual meeting of the American Academy of Orthopaedic Surgeons.
Localization of tyrosine‐phosphorylated proteins in cultured mouse dorsal root ganglion neurons
Authors: Shirasu Mikihiro , Morihara Toru , Okajima Seiichiro , Tamai Kazuo , Mizoguchi Akira , Ide Chizuka , Hirasawa Yasusuke 
Published: February 2005

AbstractThe present study, using confocal laser scanning microscopy and immunoelectron microscopy, examined the intracellular localization of tyrosine‐phosphorylated proteins in cultured mouse dorsal root ganglion neurons with special reference to their growth cones. The growth cone is the specialized structure formed at the growing tip of the axon; characteristically highly motile with filopodia on the surface, it is responsible for the extension and guidance of the neurites to the appropriate targets during nerve regeneration. It has been suggested that protein‐tyrosine phosphorylation plays an important role in the intracellular signal transduction that regulates the extension and motility of growth cones. By fluorescence immunocyto‐chemistry, phosphotyrosine immunoreactivity was found in the growth cones and neurites. Some of the filopodia exhibited strong immunoreactivity at their tips. By immunoelectron microscopy, a large number of immunogold particles (gold particles conjugated to the secondary antibody) were seen to be distributed in the cytoplasm and some were observed on the plasma membrane in the growth cones, whereas in the neurites the density of immunogold particles was the same in the axoplasm as on the plasma membranes. These findings suggest that in the growth cones phosphotyrosines might mainly be involved in intracellular signaling for maintaining their high motility whereas in the neurites they might mostly be associated with the receptor proteins at the plasma membrane for adhesion as well as for growth of neurites. Thus, tyrosine phosphorylation might contribute to different functions for growth cones and neurites.
Interleukin‐10 inhibits cytokine synthesis in monocytes stimulated by titanium particles: Evidence of an anti‐inflammatory regulatory pathway
Authors: Pollice Paul F. , Hsu James , Hicks David G. , Bukata Susan , Rosier Randy N. , Reynolds Paul R. , Puzas J. Edward , O'Keefe Regis J. 
Published: February 2005

AbstractThe anti‐inflammatory mediator interleukin‐10 was investigated as a potential inhibitor of pro‐inflammatory cytokine release in human peripheral blood monocytes activated with titanium particles. It inhibited the secretion of both tumor necrosis factor‐alpha and interleukin‐6 in a dose‐dependent manner, with complete inhibition observed at 2 ng/ml. Co‐culture experiments were performed to determine whether this cytokine may have functional importance as an inhibitor of the inflammatory response. When unstimulated lymphocytes and monocytes were co‐cultured with titanium‐stimulated monocytes, they significantly suppressed the secretion of both interleukin‐6 and tumor necrosis factor‐alpha. The inhibitory effect of these co‐cultured cells could be partially blocked with the addition of an interleukin‐10 neutralizing antibody. Interleukin‐10 levels were measured in monocyte cultures treated with titanium particles as well as in fresh monocyte cultures treated with conditioned medium from titanium‐stimulated monocytes. The latter experiments demonstrated marked stimulation of interleukin‐10 secretion in conditioned medium‐treated cultures, an effect that was related to the presence of tumor necrosis factor‐alpha in the conditioned medium. The addition of titanium to conditioned medium‐treated cultures markedly reduced the secretion of interleukin‐10, suggesting that the most responsive cells are unstimulated monocytes exposed to agents released from activated monocytes. Altogether, the expression and responsiveness to interleukin‐10 suggest a potential role for anti‐inflammatory cytokines in regulation of the inflammatory response to wear debris.
Measurement of the charge properties of articular cartilage by an electrokinetic method
Authors: Minassian A. , O'Hare D. , Parker K. H. , Urban J. P. G. , Warensjo K. , Winlove C. P. 
Published: February 2005

AbstractThe charge structure of the surface of articular cartilage determines its interactions with the macromolecules and cells of synovial fluid. It may thereby be important to the physiological function and pathological degeneration of the tissue. To determine whether the electrokinetic properties of the surface differ from those of the bulk tissue, we measured the streaming potential generated by the flow of electrolyte over the surface of a cartilage plug mounted in a chamber built for that purpose. We then calculated the effective surface charge density. In nonfibrillated cartilage from the human femoral head, the surface charge density, 0.037 ± 0.004 Cm−2 (mean ± SD), was approximately half that measured at the surface of slices cut from the middle and deep zones. In addition, the surface charge density fell relatively little at low pH; this is consistent with a higher proportion of strongly acidic groups. The variations in surface charge density were found to be similar to those in total fixed charge density in the slices by the tracer cation method. Therefore, no evidence exists that the actual surface differs in composition from the immediately underlying matrix. The addition of synovial fluid (0.0025 ml/ml) to the superfusing solution reduced the surface charge density by 25 ± 9% (n = 5), and we attributed this to the binding of synovial‐fluid macromolecules.
Deformation of articular cartilage collagen structure under static and cyclic loading
Authors: Kääb Max J. , Ito Keita , Clark John M. , Nötzli Hubert P. 
Published: February 2005

AbstractRelatively little is known about the morphology of articuar cartilage under conditions of normal use. yet a more profound knowledge is both critical to the understanding of cartilage function and helpful for the validation of tissue‐engineered cartilage. In this study, the deformation of the articular cartilage of the tibial plateau under compressive static and cyclic loading is characterized. Whole knee joints of rabbits were loaded ex vivo while the knee was held statically or allowed to move against resistance. Load magnitudes of quadriceps were maintained at either three (high) or one (low) times body weight for 30 minutes. For cyclic loading, the tibia was flexed between 70 and 150° relative to the femur at 1 Hz with either a cyclic or constant force. The recovery of cartilage after unloading was examined for each loading condition. At the end of the loading, specimens were cryofixed while under load, freeze‐substituted, and prepared for scanning electron microscopy. Morphological examination demonstrated significantly higher deformation of the collagen structure throughout all cartilage zones under static loading conditions compared with cyclic loading condition's in which deformation was limited to the superficial regions. The minimum thickness of the cartilage that remained after loading was dependent on the magnitude of load and was significantly smaller with static loads (54% of the thickness of the unloaded controls) than after cyclic loading or constant‐force cyclic loading (78 or 66% of the thickness of the unloaded controls, p < 0.05). Acute bending of the collagen fibers was observed under both loading conditions: in the superficial half of the articular cartilage after static loading and in the superficial quarter after cyclic loading. Complete recovery of all deformation occurred within 30 minutes but was significantly faster after cyclic loading. These data suggest that the structure of the collagen of articular cartilage exhibits a zone‐specific deformation that is dependent on the magnitude and type of load.
Foot asymmetry in healthy adults: Elliptic fourier analysis of standardized footprints
Authors: Sforza Chiarella , Michielon Giovanni , Fragnito Nicola , Ferrario Virgilio F. 
Published: February 2005

AbstractThe size and shape of paired structures differ in the left and right sides of the body, Shape characteristics should be analyzed separately from size to supply information about the normal variations of human organs, In the present study, the within‐subject normal symmetry of footprint shape and size was analyzed from a mathematical standpoint. On the standardized left and right footprints of 46 healthy adults (23 women and 23 men; 19–26 years old), the outline of each foot excluding the toes was identified and its shape was quantified independently from size by the elliptic Fourier analysis. The symmetry in shape was quantified on an intra‐subject basis by calculating a morphologic distance D between the mathematical reconstructions of the left and right footprints of each subject, Symmetry in size was assessed by the right‐to‐left area ratio and found to be very good for all subjects; it ranged from 0.948 to 1.049. The subjects were also grouped by sex, and mean values were calculated, Within‐subject symmetry in the footprint shape appeared high, with morphologic distances ranging between 8.94 and 2.66 in men and between 7.15 and 3.09 in women, No consistent associations between footprint symmetry and age, body height and weight, or shoe size were found, On average, women had more symmetric size‐standardized footprints than did men (women: mean 4.57, SD 1.14; men: mean 5.46. SD 1.7; p 0.05), Mean size‐independent shapes of male and female left and right footprints were also calculated, Together with the analysis of individual asymmetry, they could be used for the quantitative diagnosis of borderline patients.
Patellar tendon augmentation after removal of its central third limits joint tissue changes
Authors: Atkinson P. J. , Oyen‐Tiesma M. , Zukosky D. K. , DeCamp C. E. , Mackenzie C. D. , Haut R. C. 
Published: February 2005

AbstractThe central third of the patellar tendon is commonly used to reconstruct the injured anterior cruciate ligament. Some studies have noted changes in joint tissues following this procedure. It has been postulated that these changes may be associated with increased stress on the remaining tendon following harvest of the graft. In our study, the central third of the patellar tendon was excised in three groups of rabbits. The central tendon defects in two of the three groups were fitted with different augmentation devices to augment the host tendon during the healing process. All rabbits followed a daily treadmill exercise regimen for 12 weeks following the operation. Biomechanical testing of the tendon revealed that in nonaugmented tendons the cross‐sectional area and the length of the patellar tendon significantly increased 112 and 16%, respectively. There was histological evidence of host‐tendon remodeling throughout the cross section and extensive fibrosis in the infrapatellar fat pad. Augmentation of the tendon significantly reduced these changes, with the least change noted in the group with the greatest augmentation. The rabbits with augmentation devices retained tendon dimensions similar to those of the contralateral intact tendon, and tendon remodeling occurred only in the defect area. The rabbits with augmentation devices exhibited little to no fibrosis of the fat pad. Structural properties of augmented and nonaugmented tendons were similar despite the size differences, indicating higher tissue quality in the augmented tendons. This study suggested that complications of the knee joint (i.e., tendon proliferation and fat pad fibrosis) noted after anterior cruciate‐ligament reconstruction with the autogenous patellar tendon may be limited by the implantation of an augmentation device.
Elastic anisotropy and collagen orientation of osteonal bone are dependent on the mechanical strain distribution
Authors: Takano Yuichi , Turner Charles H. , Owan Ichiro , Martin R. Bruce , Lau Stanley T. , Forwood Mark R. , Burr David B. 
Published: February 2005

AbstractThere is evidence that the collagen microarchitecture of bone is influenced by mechanical stresses or strains. We hypothesized that peak functional strains correlate with the elastic anisotropy and collagen orientation of bone tissue and that the bone anisotropy might be changed by altering the strain patterns in canine radii for 12 months. We tested these hypotheses in studies using nine adult foxhounds. The baseline group (n=3) had three rosette strain gauges placed around the midshaft of the radius, and strain distributions were measured during walking. The osteotomy osteotomy group (n=3) had 2 cm of the ulna surgically removed, and the sham group (n=3) received a sham osteotomy. The osteotomy and sham groups were allowed free movement in cages with runs for 12 months, after which strain distributions were measured on the radii during walking. Bone‐tissue anisotropy and collagen architecture were measured in radii from which the in vivo longitudinal strain patterns had been measured. The collagen birefringence patterns were measured with use of a circularly polarized light technique, and the elastic anisotropy of the bone, mineral, and collagen matrix was evaluated with a novel acoustic microscopy technique. Peak longitudinal strains in the radius correlated with the normalized longitudinal structure index (a polarized light measure of collagen birefringence) and the tissue anisotropy ratio. The average anisotropy ratio was 1.28 ± 0.01 in the posterior (compressive) cortex and 1.43 ± 0.01 in the anterior (tensile) cortex (these values are significantly different at p < 0.0001). The ulnar osteotomy changed the strain pattern on the radius, causing increased tensile strains in the medial cortex by more than 5‐fold that were associated with a significant increase in the anisotropy ratio in the bone tissue. The longitudinal structure index was strongly correlated (r=0.62, p < 0.005) with the anisotropy ratio of demineralized bone but was not correlated with that of deproteinized bone; this indicates that it reflects collagen fibril orientation in the bone matrix. These results indicate that mechanical strains affect both collagen and mineral microarchitecture in bone tissue, i.e., tensile strains are associated with increased tissue anisotropy and compressive strains, with decreased anisotropy.
Bioreactor cultivation conditions modulate the composition and mechanical properties of tissue‐engineered cartilage
Authors: Vunjak‐Novakovic G. , Martin I. , Obradovic B. , Treppo S. , Grodzinsky A. J. , Langer R. , Freed L. E. 
Published: February 2005

AbstractCartilaginous constructs have been grown in vitro with use of isolated cells, biodegradable polymer scaffolds, and bioreactors. In the present work, the relationships between the composition and mechanical properties of engineered cartilage constructs were studied by culturing bovine calf articular chondrocytes on fibrous polyglycolic acid scaffolds (5 mm in diameter, 2‐mm thick, and 97% porous) in three different environments: static flasks, mixed flasks, and rotating vessels. After 6 weeks of cultivation, the composition, morphology, and mechanical function of the constructs in radially confined static and dynamic compression all depended on the conditions of in vitro cultivation. Static culture yielded small and fragile constructs, while turbulent flow in mixed flasks yielded constructs with fibrous outer capsules; both environments resulted in constructs with poor mechanical properties. The constructs that were cultured freely suspended in a dynamic laminar flow field in rotating vessels were the largest, contained continuous cartilage‐like extracellular matrices with the highest fractions of glycosaminoglycan and collagen, and had the best mechanical properties. The equilibrium modulus, hydraulic permeability, dynamic stiffness, and streaming potential correlated with the wet‐weight fractions of glycosaminoglycan, collagen, and water. These findings suggest that the hydrodynamic conditions in tissue‐culture bioreactors can modulate the composition, morphology, mechanical properties, and electromechanical function of engineered cartilage.