bluuebunny/crossref_metadata_2025_split huggingface dataset:
Human monocyte response to particulate biomaterials generated in vivo and in vitro
Authors: Shanbhag Arun S. , Jacobs Joshua J. , Black Jonathan , Galante Jorge O. , Glant Tibor T. 
Published: February 2005

AbstractWe studied the ability of four clinically relevant particle species to stimulate human peripheral blood monocytes to release bone‐resorbing agents, including interleukin‐1 (both interleukin‐1α and interleukin‐1β), interleukin‐6, and prostaglandin E2. The species studied were titanium‐6%aluminum‐4%vanadium (TiAlV), commercially pure titanium, fabricated ultrahigh molecular weight polyethylene, and polyethylene retrieved from interfacial membranes of failed uncemented total hip arthroplasties. For all species, the mean size was less than 1 μm. Human peripheral blood monocytes were challenged with these particles in a uniform manner on the basis of surface area. Phorbol 12‐myristate acetate, zymosan, and nonphagocytosable titanium particles served as controls. Stimulation of human monocytes is a function of the composition and concentration of particles. In this study. TiAlV particles appeared to be the most competent to elicit the synthesis and release of inflammatory mediators. Particles of commercially pure titanium and of fabricated ultrahigh molecular weight polyethylene also could induce the release of various cellular mediators, albeit at a lower level, whereas the particles of polyethylene retrieved from interfacial membranes were less stimulatory in these short‐term in vitro experiments.
Quantitation of articular cartilage using magnetic resonance imaging and three‐dimensional reconstruction
Authors: Marshall K. W. , Mikulis D. J. , Guthrie B. M. 
Published: February 2005

AbstractA quadrature knee coil was used in conjunction with a magnetic resonance imaging scanner for quantitation of test phantom volumes, ex vivo bovine cartilage thickness, and in vivo human articular cartilage volumes. Optimal magnetic resonance parameters were obtained by testing a series of spin‐echo and gradient‐echo pulse sequences to determine the sequence that provided the highest resolution of articular cartilage and best defined the cartilage interfaces with synovial fluid and subchondral bone. Extensive testing revealed that two sequences were required to define articular cartilage accurately: a spoiled gradient‐echo sequence and a steady state free‐precession sequence. Three‐dimensional reconstruction and statistical analyses of test phantoms and of bovine and human cartilage images were performed. Differences between actual phantom volumes and three‐dimensional measurements demonstrated that, as magnetic resonance slice thickness was increased, the measurement variability also increased (coefficient of variation ranging from 1.7 ± 1.3% for 1.0 mm slice thickness to 22.7 ± 1.9% for 3.0 mm slice thickness). When the phantom volume was greater than 1,800 mm3, the intraobserver, interobserver and interscan accuracies were greater than 97, 98, and 96%, respectively. This high degree of reproducibility pertained for the data on in vivo human cartilage data also. For experienced observers, the intraobserver and interobserver reproducibility were greater than 98 and 97%, respectively. The interscan reproducibility was greater than 98%. These data demonstrate that improved magnetic resonance pulse sequencing, in conjunction with three‐dimensional reconstruction and measurement techniques, can accurately and reproducibly measure the volume of articular cartilage. Clinical application of this approach offers the potential for early diagnosis of osteoarthritis and for serial, noninvasive assessment of changes in articular cartilage volume in response to therapeutic modalities.
Effects of valgus tibial angulation on cartilage degeneration in the rabbit knee
Authors: Lovász György , Llinás Adolfo , Benya Paul , Bodey Béla , McKellop Harry A. , Luck James V. , Sarmiento Augusto 
Published: February 2005

AbstractThirteen adult female rabbits underwent unilateral osteotomy of the proximal tibia. In nine animals, 30° of valgus angulation was created; in four animals, osteotomy without angulation was performed. After a 12‐week survival period, the knee joints were processed for histology by staining with hematoxylin and eosin and safranin O. Additionally, the chondroitin sulphate epitopes 3‐B‐3 (−) and 7‐D‐4 were evaluated immunohistochemically as markers of osteoarthritis. Changes of the articular surface of the tibia were visualized by scanning electron microscopy. Light microscopic evaluation by the Mankin et al. scoring system revealed mild or moderate damage of the cartilage in the lateral compartment of angulated extremities when compared with the control side. Immunohistology with the monoclonal 3‐B‐3 and 7‐D‐4 antibodies showed no increased expression of these epitopes in the lateral compartments of the knee. Scanning electron microscopic evaluation of the tibial surfaces revealed slight surface damage localized to the central, weight‐bearing portion of the lateral tibial plateau of angulated extremities. Angulation of 30° led to only mild degenerative changes of the cartilage. These results indicate that, in the short term, cartilage has considerable capacity to withstand the effects caused by severe angulation of the limb.
Dose‐dependent response of gamma irradiation on mechanical properties and related biochemical composition of goat bone‐patellar tendon‐bone allografts
Authors: Salehpour A. , Butler D. L. , Proch F. S. , Schwartz H. E. , Feder S. M. , Doxey C. M. , Ratcliffe A. 
Published: February 2005

AbstractWe studied the effects of gamma irradiation on the dimensions, mechanical and material properties, and mature hydroxypyridinium crosslink density of collagen in goat patellar tendon‐bone specimens. Left and right patellar tendon‐bone units were removed from 10 adult female goats and were bisected longitudinally. Each tendon half was frozen, and then the left halves were exposed to 4, 6, or 8 Mrad (40,000,60,000, or 80,000 Gy) of gamma irradiation. The contralateral tendon halves served as controls (no irradiation). Each specimen then was loaded to failure in tension, and its soft‐tissue midsubstance was processed to measure collagen content and hydroxypyridinium crosslink density. Dose‐dependent reductions in the mechanical properties were found, including 46% (p < 0.01) and 18% (p < 0.05) reductions in maximum force and stiffness, respectively, at 4 Mrad. Similar reductions were noted in material properties, including 37% (p < 0.005) and 8% (p > 0.05) reductions in maximum stress and modulus, respectively, at 4 Mrad. These results are consistent with our previous report involving 2 and 3 Mrad (20,000 and 30,000 Gy) of exposure. We also found significant decreases in hydroxypyridinium crosslink density with 6 Mrad of irradiation (p < 0.05). However, since only one biomechanical parameter (modulus) correlated significantly with only one biochemical measure (hydroxypyridinium crosslink density) (p < 0.05), other possible mechanisms also are being explored to more fully explain these dose‐dependent changes.
Intraoperative graft tensioning alters viscoelastic but not failure behaviours of rabbit medial collateral ligament autografts
Authors: King Graham J. W. , Edwards Pamela , Brant Rollin F. , Shrive Nigel G. , Frank Cyril B. 
Published: February 2005

AbstractThe effects of three different degrees of intraoperative graft tensioning on measures of ex vivo laxity, viscoelastic behaviour, and structural and material failure of isolated healing medial collateral ligament autografts were investigated in a rabbit model. The grafts were orthotopically replaced at one of three different loads (too tight, anatomic, or too loose) and were mechanically evaluated after 0, 12, 24, and 48 weeks of healing. Laxity of the ligament was influenced by intraoperative graft tensioning at time zero. However, after 12 weeks of healing, values for laxity were indistinguishable among the experimental groups. Cyclic load relaxation, a measure of viscoelastic behaviour, was significantly influenced by intraoperative graft tensioning, and this effect persisted even after 48 weeks of healing. Grafts placed under excessive tension relaxed one‐third less than grafts placed under abnormally low in situ tension. The relevance of these differences remains to be determined. Intraoperative tensioning had no significant influence on characteristics of structural or material failure of the graft during the first year of healing. These results suggest that, in this model, control of graft tension at the time of placement and fixation does not improve the failure characteristics of the medial collateral ligament. The structural strength of the grafts collectively improved to nearly normal values after 48 weeks; however, material recovery was less complete. Failure loads averaged 89% of control values, whereas failure stress averaged only 52% after 48 weeks of healing.
Soft‐tissue “flaws” are associated with the material properties of the healing rabbit medial collateral ligament
Authors: Shrive N. , Chimich D. , Marchuk L. , Wilson J. , Brant R. , Frank C. 
Published: February 2005

AbstractThis study evaluated microscopic flaws in the healing rabbit medial collateral ligament and their significance in terms of the material properties of this ligament during healing. A gap injury was created in the midsubstance of the medial collateral ligament in the right hindlimb of 15 skeletally mature (12 months old) New Zealand White rabbits. At postoperative intervals of 3, 6, or 14 weeks, histomorphometric analysis of the flaws was carried out in subgroups of animals. The medial collateral ligaments from four of the left hindlimbs (randomly selected) were used as uninjured contralateral controls. In one histologic section of each area of scar tissue and the analogous area in the controls, specified tissue flaws (blood vessels, fat cells, hypercellular areas, loose matrix, disorganized matrix, or a combination of these) were measured by four independent and blinded observers. The results showed that the mean total area of the flaws, as a percentage of the total section, and the mean area of the largest flaw decreased with healing time in each healing group but did not achieve control values by 14 weeks. Because it was not possible to test the healing medial collateral ligaments mechanically prior to measurement of the flaws (due to the destructive nature of failure testing), the data on the flaws were compared with the material strength and stiffness of a separate series of similarly injured and mechanically tested medial collateral ligaments (data published previously). A maximum likelihood statistical analysis showed a very strong functional association between the mean area of the largest flaw and the stress at failure (p < 0.004) and between the mean flaw area as a percentage of the total section area and the elastic modulus (p < 0.001). This study therefore demonstrates that it is possible to quantify material flaws in scar tissue in rabbit medial collateral ligaments, that these flaws become smaller with healing time as the scar remodels, and that flaws are functionally associated with the material properties of the ligament in this model (larger flaws with less tensile strength and more flaws with less stiffness).
Expression of interleukin‐6 in osteoarthritic chondrocytes and effects of fluid‐induced shear on this expression in normal human chondrocytes in vitro
Authors: Mohtai M. , Gupta M. K. , Donlon B. , Ellison B. , Cooke J. , Gibbons G. , Schurman D. J. , Smith R. Lane 
Published: February 2005

AbstractThis study tested the effect of fluid‐induced shear on interleukin‐6 expression in normal human articular chondrocytes in vitro. As determined by Northern blot analysis, interleukin‐6 mRNA expression occurs in chondrocytes from osteoarthritic cartilage but not in normal chondrocytes. Applying fluid‐induced shear stress to primary high density cultures of chondrocytes increased interleukin‐6 mRNA signal 4‐fold at 1 hour and 10 to 15‐fold at 48 hours compared with unsheared control cultures. At 48 hours, fluid‐induced shear stress increased interleukin‐6 protein levels in the culture medium 9 to 10‐fold compared with unsheared controls, mRNA signals for interleukin‐1α, interleukin‐1β, and tumor necrosis factor‐α in RNA from sheared or control chondrocytes were not detected by Northern blotting. Transforming growth factor‐β mRNA signal was detectable but was not affected by shear. In contrast, human lung fibroblasts (WI‐38) responded to fluid‐induced shear with increased signal for transforming growth factor‐β but not interleukin‐6, mRNA. Both cell types did respond to interleukin‐1α with increased interleukin‐6 mRNA signal. These data demonstrate that distortional forces, such as fluid‐induced shear stress, alter interleukin‐6 levels in normal chondrocytes in vitro and suggest that increased interleukin‐6 expression in osteoarthritic cartilage may result, in part, from alterations in the mechanical loading of the tissue.
Repopulation of laser‐perforated chondroepiphyseal matrix with xenogeneic chondrocytes: An experimental model
Authors: Caruso Enzo M. , Lewandrowski Kai‐Uwe , Ohlendorf Christian , Tomford William W. , Zaleske David J. 
Published: February 2005

AbstractGrowth of chondrocytes into a xenogeneic chondroepiphyseal matrix was investigated in an in vitro experimental model by combining viable calf chondrocytes with chick epiphyseal matrix devoid of viable chondrocytes. The chondrocytes were harvested from the wrist joints of newborn calves and cultured for 2 days. The epiphyses were harvested from the distal femurs and the proximal tibias of fetal chicks after development was arrested at 17 days by freezing. The epiphyseal specimens were prepared in four ways. These included femoral and tibial epiphyses without holes and femoral and tibial epiphyses with holes made by a laser. These epiphyseal specimens were co‐cultured with calf chondrocytes for various periods. After digestion of the epiphyseal matrix, viable chondrocytes were counted in suspension. Chondrocyte division in the matrix was assessed by [3H]thymidine incorporation. The growth of calf chondrocytes into the xenogeneic chick matrix was evaluated by fluorescence microscopy on fresh thick epiphyseal sections. The percentage of viable chondrocytes in the xenogeneic epiphyseal matrix increased with culture time to a maximum at day 21. The addition of laser‐drilled holes was found to extend a plateau of chondrocyte viability until day 29. A decrease in cell viability was detected at later observation points. This study demonstrates that xenogeneic matrix may serve as a morphogenetic scaffold for chondrocytic growth.
Responses of mechanoreceptor neurons in the cat knee joint capsule before and after anterior cruciate ligament transection
Authors: Khalsa Partap S. , Grigg Peter 
Published: February 2005

AbstractIt is known that afferent neurons play a protective role in knees made unstable by transection of the anterior cruciate ligament. However, it is not known whether cutting the anterior cruciate ligament has an effect on the response of the sensory neurons that innervate the joint. In this study, the responsiveness (activation threshold and position sensitivity) of single, mechanically sensitive afferent neurons from the cat knee was evaluated by a series of extension, internal, and external rotations. The anterior cruciate ligament then was cut and the same procedure was repeated. Transection of the ligament increased joint laxity for all types of rotations. The responsiveness of the neurons was not changed significantly by cutting the ligament (p > 0.05). Therefore, capsule afferents continue to behave normally in joints in which the anterior cruciate ligament has been transected.
Musculoskeletal function assessment instrument: Criterion and construct validity
Authors: Engelberg Ruth , Martin Diane P. , Agel Julie , Obremsky William , Coronado Gloria , Swiontkowski Marc F. 
Published: February 2005

AbstractThe Musculoskeletal Function Assessment (MFA) instrument, a health status instrument with 100 self‐reported health items; was designed for use with the broad range of patients with musculoskeletal disorders of the extremities commonly seen in clinical practice. In this paper, we report on its criterion and construct validity. Criterion validity was tested against physicians' ratings of patient functioning (e.g., upper functioning, lower functioning, daily activities, recreational functioning, emotional adjustment, and overall functioning) and standard clinical measures (e.g., grip strength, walking speed, fine motor skills, knee and elbow strength, and range of motion). Significant correlations (p ⩽ 0.05) between its scores, physicians' ratings, and clinical measures support the MFA's criterion validity. Construct validity was demonstrated against existing measures of health status (e.g., measures of lower and upper mobility, activity level and satisfaction, health status, social support, pain, emotional status, and quality of life), in accordance with clinical hypotheses about the effect of musculokeletal disorders on functioning (e.g., type and number of problems, severity of illness or injury, and comorbidites) and by an analysis of demographic characteristics (e.g., sex, education, income, health insurance, and employment) against the MFA scores. Discriminant construct validity was supported in an analysis of MFA scores by patient disease groups (p ⩽ 0.01).
Subfailure injury of the rabbit anterior cruciate ligament
Authors: Panjabi Manohar M. , Yoldas Erol , Oxland Thomas R. , Crisco Joseph J. 
Published: February 2005

AbstractLigamentous injuries range in severity from a simple sprain to a complete rupture. Although sprains occur more frequently than complete failures, only a few studies have investigated the phenomena of these subfailure injuries. The purpose of our study was to document the changes in the load‐deformation curve until the failure point, after the ligament has been subjected to an 80% subfailure stretch. Thirteen paired fresh rabbit bone‐anterior cruciate ligament‐bone preparations were used. One of the pairs (control) was stretched until failure; the other (experimental) was first stretched to 80% of the failure deformation of the control and then stretched to failure. Comparisons were made between the load‐deformation curves of the experimental and control specimens. The nonlinear load‐deformation curves were characterized by eight parameters: failure load (Ffail), failure deformation (Dfail), energy until failure (Efail), deformations measured at 5, 10, 25, and 50% of the failure load (D5, D10, D25, and D50, respectively), and stiffness measured at 50% of the failure force (K50). There were no significant differences in the values for Ffail, Dfail, and Efail between the experimental and control ligaments (p > 0.33). In contrast, the deformation values were all larger for the experimental than the control ligaments (p < 0.01). The deformations D5, D10, D25, and D50 (mean ± SD) for the control were 0.36 ± 0.13, 0.49 ± 0.23, 0.81 ± 0.35, and 1.23 ± 0.41 mm. The corresponding deformations for the experimental ligaments were, respectively, 209, 186, 153, and 130% of the control values. K50 was also greater for the experimental ligament (125.0 ± 41.7 N/mm compared with 108.7 ± 31.4 N/mm, p < 0.03). These findings indicate that even though the strength of the ligament did not change due to a subfailure injury, the shape of the load‐displacement curve, especially at low loads, was significantly altered. Under the dynamic in vivo loading conditions of daily living, this may result in increased joint laxity, additional loads being applied to other joint structures, and, with time, to joint problems.
Stable partial debonding of the cement interfaces indicated by a finite element model of a total hip prosthesis
Authors: Lu Zhen , Ebramzadeh Edward , McKellop Harry , Sarmiento Augusto 
Published: February 2005

AbstractA simplified three‐dimensional finite element model of the femoral component of a cemented total hip prosthesis was used to investigate whether partial debonding at the stem‐cement or bone‐cement interfaces propagates in a stable or unstable manner, and to assess the resultant variation of the stresses within the cement layer. The likelihood of unstable debonding under tensile failure mode was assessed both by a conventional monotonic strength criterion and by a fracture mechanics approach that took into account debonding due to fatigue loading. The model predicted that partial debonding at the cement interfaces would be stable and would not precipitate complete debonding. Among the various bonding conditions that were investigated, the maximum tensile stress within the cement layer was least with a small amount of debonding rather than with complete bonding. These results were consistent with clinical observations of nonprogressive or slowly progressive separation at cement interfaces in cemented femoral components that were otherwise well functioning and asymptomatic.
Biomechanical effects of stress shielding of the rabbit patellar tendon depend on the degree of stress reduction
Authors: Majima Tokifumi , Yasuda Kazunori , Fujii Takashi , Yamamoto Noritaka , Hayashi Kozaburo , Kaneda Kiyoshi 
Published: February 2005

AbstractA rabbit model was used to discover whether the effects of stress shielding on the mechanical properties of the patellar tendon depend on the degree of stress reduction. Ninety mature female Japanese White rabbits were divided into three groups: completely stress‐shielded, partially stress‐shielded, and shamoperation and contralateral controls. In the experimental groups, tension applied to the patellar tendon was 0%, approximately 30%, and 100%, of the normal tension, respectively, with a polyester artificial ligament. Tensile tests were carried out on patella‐patellar tendon‐tibia complexes harvested 1, 2, 3, 6, or 12 weeks after surgery. The tensile strength decreased in comparison with the sham‐operation group to 50.2, 13.5, 9.7, and 20.7% in the completely stress‐shielded group and to 75.2, 57.6, 59.6, 57.3, and 72.9% in the partially stress‐shielded group. The tensile strength in the completely stress‐shielded group was significantly less than that in the partially stress‐shielded group at 1, 2, 3, and 6 weeks. The cross‐sectional area of the patellar tendon significantly increased to 132, 206, 237, and 136% in the completely stress‐shielded group and to 136, 170, 175, 155, and 127% in the partially stress‐shielded group, compared with the sham‐operation group. The cross‐sectional area of the completely stress‐shielded tendon was significantly larger than that of the partially stress‐shielded tendon at 1, 2, and 3 weeks. This study demonstrated that effects of stress shielding on the mechanical properties of the patellar tendon were dependent on the degree of stress shielding.