bluuebunny/crossref_metadata_2025_split huggingface dataset:
Elastase activity, uninhibited by α1‐antitrypsin, in the periprosthetic connective matrix around loose total hip prostheses
Authors: Takagi Michiaki , Konttinen Yrjö T. , Santavirta Seppo , Kangaspunta Petri , Sorsa Timo , Yamakawa Mitsunori , Suda Akio 
Published: February 2005

AbstractTo clarify the proteolytic cascade in the loosening of total hip prostheses, the presence, tissue localization, and content of the serine proteinase, elastase, and its endogenous inhibitor, α1‐antitrypsin, were studied in perioprosthetic tissues around 12 loose hip prostheses by immunohistochemistry, spectrophotometric enzyme assay, and immunoblot analysis, and the results were compared with those in control synovial tissue samples from eight knees. Increased numbers of elastase‐immunoreactive cells and elevated elastase activity, inhibited by the addition of native α1‐antitrypsin, were observed both in the interface tissues between the bone and implants and in the pseudocapsular tissues from around loose hip prostheses. Elevated elastase activity, uninhibited by α1‐antitrypsin in situ and inhibited by the addition of native inhibitor, suggests a proteinase‐inhibitor imbalance that contributes to the weakening of periprosthetic tissues and thus causes the loosening of hip prostheses.
In vitro evaluation of bonding of the cement‐metal interface of a total hip femoral component using ultrasound
Authors: Davies Jeff P. , Tse M‐K. , Harris W. H. 
Published: February 2005

AbstractDebonding of the cement‐metal interface of a cemented femoral component is one mechanism associated with loosening of total hip replacement. An ultrasonic pulse‐echo technique was developed to determine, nondestructively, the integrity of the cement‐metal interface in vitro. The characteristics of the ultrasonic reflections of bonded and debonded interfaces were obtained by using a physical model that consisted of a flat slab of cement and a flat cobalt alloy plate with known conditions of bonded and debonded interfaces. The same model was used to establish that the ultrasonic technique could distinguish between two surfaces that were in direct apposition but not bonded and those that were actually bonded. This technique then was shown to be useful in nondestructively detecting bonded and debonded cement‐metal interfaces of femoral prostheses cemented into fiberglass femurs and femurs from human cadavera.
Femoral component migration in total knee arthroplasty: Randomized study comparing cemented and uncemented fixation of the Miller‐Galante I design
Authors: Nilsson Kjell G. , Kärrholm Johan , Linder Lars 
Published: February 2005

AbstractThe Miller‐Galante I knee replacement was inserted in 25 women and three men (33 knees) with osteoarthrosis. All patients received a TiAIV femoral component with a commercially pure titanium fibermesh undersurface. Cemented or cementless fixation was used based on a randomization protocol. Micromotions of the femoral components were recorded with roentgen stereophotogrammetric analysis during the first 2 postoperative years. The magnitude of migration did not differ between cemented and uncemented fixation. The number of nonmigrating prostheses decreased from 21 (12 cemented and nine uncemented) at 3 months to six (three cemented and three uncemented) at 24 months. In both groups, the magnitude of prosthetic tilting about the longitudinal axis (internal‐external rotation) was as large as that about the transverse axis (flexion‐extension). Rotation into extension was as common as rotation into flexion. The largest translations were recorded at either of the posterior condyles. In 10 uncemented components, radiolucent lines were seen at the distal interface postoperatively. Proximal migration of the femoral component was recorded in these knees, and the width of the lines decreased or the lines disappeared totally at 24 months. After 2 years, lines were noted around four cemented and four uncemented replacements, mainly anteriorly or distally. All of these prostheses migrated. One prosthesis, revised because of malalignment, displayed pronounced migration after an initial period of stability. Bone ingrowth was observed anteriorly and anterodistally despite the presence of motions of 1 mm or more.
Reperfusion injury in vascularized bone allografts
Authors: Moran Christopher G. , McGrory Brian J. , Bronk James T. , Wood Michael B. 
Published: February 2005

AbstractA vascularized allograft canine tibia was used to evaluate the preservation of the osseous microcirculation. Six pairs of adult tibiae were harvested, and a vascular washout was performed with mannitol solution. The bones then were perfused continuously (0.03 ml/min at 5°C) for 20 hours with University of Wisconsin solution. Following storage, each pair of bones was transplanted, by microvasacular anastomosis, to a recipient dog, and bone blood flow was estimated using the radiolabeled microsphere method. Adreno‐receptor control mechanisms were evaluated in one specimen, and endothelial function was evaluated in the contralateral specimen. Alpha1‐adrenoreceptor blockade produced a significant increase (89 ± 80%) in bone blood flow (p < 0.05). A further increase (99 ± 56%) was observed with the addition of alpha2‐blockade (p < 0.01). Acetylcholine produced a decrease (65 ± 65%) in blo od flow (p < 0.1). This effect was inhibited by L‐NG‐monomethyl‐arginine, which resulted in an increase (53 ± 47%) in bone blood flow (p < 0.05). The no‐reflow phenomenon was observed in two vascularized allografts. These results demonstrate that smooth muscle adrenoreceptors were preserved successfully for 24 hours. In contrast, endothelial function was abnormal. There was no evidence that the endothelium was producing endothelium‐derived relaxing factor, and the results suggest that an endothelium‐derived constricting factor dependent on L‐arginine was produced during reperfusion. It is concluded that University of Wisconsin solution does not preserve normal endothelial function in the microcirculation of bone.
Cartilage oligomeric matrix protein: Isolation and characterization from human articular cartilage
Authors: DiCesare Paul E. , Mörgelin Matthias , Carlson Cathy S. , Pasumarti Subhalakshmi , Paulsson Mats 
Published: February 2005

AbstractCartilage oligomeric matrix protein was purified in a native form from normal adult human articular cartilage. The key steps in the purification scheme were selective extraction with buffer containing EDTA, wheat germ agglutinin affinity chromatography, and removal of the related protein thrombospondin by heparin affinity chromatography. Particles of cartilage oligomeric matrix protein viewed by electron microscopy after rotary shadowing revealed structures similar to the prototype molecule purified from Swarm rat chondrosarcoma. The protein demonstrated a bouquet‐like five‐armed structure, with peripheral globular domains connected by thin flexible strands to a central assembly domain. Immunohistochemistry revealed age‐dependent differences in the protein's distribution in cartilage. In normal human adult articular cartilage, there was a relatively uniform distribution throughout the interterritorial extracellular matrix, whereas in fetal articular cartilage, immunostaining was localized to the extracellular matrix directly adjacent to the chondrocytes. The isolation and characterization of human cartilage oligomeric matrix protein will facilitate its study in pathological conditions of human cartilage.
Use of a guanidine extract of demineralized bone in the treatment of osteochondral defects of articular cartilage
Authors: Tanaka Takaaki , Fujii Katsuyuki , Ohta Mitsunobu , Soshi Shigeru , Kitamura Atsushi , Murota Kagehisa 
Published: February 2005

AbstractIn order to evaluate the ability of a guanidine extract of demineralized bone to repair osteochondral defects in articular cartilage, plugs made of this extract were implanted into defects in rabbit knees. The repair tissue was examined macroscopically, histologically, and immunohistochemically at 4, 8, 12 and 30 weeks. Controls (defects that were left empty) showed no cartilage formation. Four weeks after implantation of a guanidine extract plug, histological examination showed a nonhomogeneous metachromatically stained region extending from the surface of the repair tissue down to cancellous bone. This region also was labeled by an anti‐type‐II collagen antibody, indicating that cartilage‐like tissue had been induced. At 8 weeks, the newly formed cartilage in the subchondral and cancellous bone had been partially replaced by bone. At 12 weeks, the thickness of the newly formed cartilage layer had decreased, and most of the newly formed cartilage in the subchondral and cancellous bone had been replaced by bone. In addition, a tidemark was observed. At 30 weeks, the repair tissue was a mixture of cartilage and fibrocartilage, and there was severe degeneration of the cartilage surrounding the repaired defects. These findings indicate that osteochondral defects of articular cartilage can be partially repaired by the implantation of a guanidine extract and that the newly formed cartilage‐like tissue is not permanent.
Structure and histopathology of the insertional region of the human achilles tendon
Authors: Rufai A. , Ralphs J. R. , Benjamin M. 
Published: February 2005

AbstractThe Achilles tendon inserts onto the calcaneus, and the retrocalcaneal bursa intervenes between it and the bone immediately proximal to the enthesis. The enthesis, the bursa, and the bursal walls form a complex insertional region protecting against wear and tear. We examined the structure and histopathology of the insertional region in 50 tendons from cadavers (age at time of death, 57‐96 years). The enthesis contained fibrocartilage typical of attachment sites. In specimens with a prominent superior tuberosity (the majority), the walls of the bursa also were fibrocartilaginous. On the anterior wall, fibrocartilage replaced the calcaneal periosteum; on the posterior wall, there was a sesamoid fibrocartilage in the deep part of the tendon. When the tuberosity was not prominent, the bursal fibrocartilages were absent. Histopathological features were observed in 31 entheses. Bone spurs extended from the calcaneus into the tendon and probably formed by endochondral ossification of enthesial fibrocartilage. Longitudinal fissures were splits in the fibrocartilage along the lines of the endotenon, and small transverse tears occurred at the tendon‐bone junction. Longitudinal fissures showed evidence of repair; they were filled with amorphous material and surrounded by clusters of cells. In the bursal walls, calcification or degeneration, or both, were observed in 37 specimens and usually involved both sesamoid and periosteal fibrocartilages. These fibrocartilages could therefore be implicated in retrocalcaneal bursitis.
Increased expression of the β1, α5 and αv integrin adhesion receptor subunits occurs coincident with remodeling of stress‐deprived rabbit anterior cruciate and medial collateral ligaments
Authors: AbiEzzi Salwan S. , Gesink Dirk S. , Schreck Paul J. , Amiel David , Akeson Wayne H. , Woods Virgil L. 
Published: February 2005

AbstractThe biomechanical, biochemical, and morphological properties of the anterior cruciate and medial collateral ligaments are dramatically altered in response to deprivation of normal physical forces and joint motion. Integrin adhesion receptors are known to play important roles in the tissue remodeling that occurs in the course of normal wound repair. We propose that integrins play a similar role in the remodeling of the extracellular matrix in stress‐deprived periarticular ligaments. This study tests the hypothesis that altered expression of integrins on ligament fibroblasts accompanies this remodeling. The left knees of 15 New Zealand White rabbits were surgically immobilized in acute flexion and the right knees served as controls (no operation). The anterior cruciate and medial collateral ligaments were harvested at 1, 3, 5, 9, or 12 weeks after immobilization. Sections from the ligaments were immunostained with monoclonal antibodies specific for the integrin subunits β1, α5, α6, and αv, as well as with a negative control antibody. Fibroblasts within both the stress‐deprived anterior cruciate and medial collateral ligaments demonstrated markedly increased staining for the β1, α5, and αv subunits, as compared with the controls. The increased staining was greatest at 9 weeks in the anterior cruciate ligament and at 12 weeks in the medial collateral ligament. Western blot study of ligament proteins extracted with sodium dodecyl sulfate demonstrated an increased amount of β1 subunit protein in both ligaments from knees that were stress deprived for 9 and 12 weeks, as compared with the control ligaments. These studies establish that stress deprivation in this animal model is accompanied by increased expression of integrin cell‐surface receptors containing the β1, α5, and αv subunits on anterior cruciate and medial collateral ligament fibroblasts, with a time course similar to that previously reported for indices of extracellular matrix remodeling induced by stress deprivation. This outcome suggests an important role for these integrins in the remodeling of stress‐deprived ligaments.
Three‐dimensional geometric and structural symmetry of the turkey ulna
Authors: Adams Douglas J. , Pedersen Douglas R. , Brand Richard A. , Rubin Clinton T. , Brown Thomas D. 
Published: February 2005

AbstractStructural models of long‐bone preparations usually assume left‐right symmetry of contralateral bones under normal (baseline) conditions. To obtain insight on how this assumption affects the detection of subtle changes (as from functional adaptation), we formally examined the three‐dimensional geometric and structural symmetry of paired long bones, using contemporary image reconstruction and stress analysis techniques. Nine pairs of ulnae from normal male turkeys were reconstructed computationally from serial transverse images obtained by either (a) mechanical sectioning and digital photographic imaging or (b) computed tomography. Computed tomography scans allowed greater precision in reconstruction than did digitally imaged photographs. Left‐right comparisons of parameters of geometric symmetry (from computed tomography reconstructions) revealed average differences in whole bone volume and whole bone principal moments of inertia of 3.6 and 3.0%, respectively. Differences in bone curvature were indexed as noncolinearity of left compared with (mirrored) right centroidal axes, giving a disparity of 0.7 ± 0.3 mm. Within the longitudinal central 20% of the diaphysis (the customary region for histomorphometry), average left‐right differences in cross‐sectional area and area principal moments of inertia for computed tomography images were 4.7 and 5.0%, respectively. The overlap of longitudinally paired cross sections of the mid‐diaphysis, aligned at common centroids and oriented in the respective principal inertial directions, was greatest (as much as 95%) in the central 20% of the diaphysis. Paired three‐dimensional finite element models demonstrated nearly identical left and right stress/strain fields throughout the ulnar diaphyses for both compressive and torsional loading. Our data suggest that the assumption of contralateral geometric symmetry in long bones should be judged in the context of the specific attribute of symmetry under consideration; however, we conclude that for purposes of finite element modeling the assumption of symmetry is reasonable.
Correlation between synthetic activity and glycosaminoglycan concentration in epiphyseal cartilage raises questions about the regulatory role of interstitial pH
Authors: Boustany Nada N. , Gray Martha L. , Black Ann C. , Hunziker Ernst B. 
Published: February 2005

AbstractCurrent data provide compelling evidence that the pH of the interstitial fluid of cartilage is an important determinant of the metabolic activity of chondrocytes, and this has served as the basis for a mechanistic proposal whereby chondrocytes could sense mechanical compression. The objective of the current study was to test this hypothesis further by examining biosynthetic activity in cartilage as a function of glycosaminoglycan content, which is the major determinant of interstitial pH. On the basis of previous data, increased biosynthetic activity would be anticipated to correlate with a decreased glycosaminoglycan content and an elevated interstitial pH. In contrast to our expectations, we found that the biosynthetic activity (monitored by measurement of incorporation of sulfate and proline) was positively correlated with the glycosaminoglycan content of tissue. These results raise doubt as to whether interstitial pH provides a dominant mechanism for controlling the metabolism of chondrocytes.
Transforming growth factor‐β1 and fibroblast growth factors in rat growth plate
Authors: Jingushi S. , Scully S. P. , Joyce M. E. , Sugioka Y. , Bolander M. E. 
Published: February 2005

AbstractChondrocytes in the growth plate progress in an orderly fashion from resting through proliferating to hypertrophic cells. In the region of hypertrophic chondrocytes, the cartilage is invaded by capillary loops and endochondral ossification is initiated. It is currently believed that growth factors may regulate the proliferation and maturation of chondrocytes and the synthesis of extracellular matrix in the growth plate. The ordered sequence of proliferation and differentiation observed in the growth plate provides a unique opportunity to study the role of acidic fibroblast growth factor, basic fibroblast growth factor, and transforming growth factor‐β1 in the regulation of these processes. In this study, expression of the mRNA of these growth factors was examined using total RNA extracted from the physis and epiphysis of rat tibias. Transforming growth factor‐β1 mRNA was detected by Northern hybridization. Expression of the genes encoding acidic and basic fibroblast growth factors was demonstrated by polymerase chain reaction amplification. In addition, using polyclonal antibodies against these growth factors, we localized them by immunohistochemical analysis. Strong intracellular staining with a predominantly nuclear pattern was observed in chondrocytes from the proliferating and upper hypertrophic zones. In contrast, chondrocytes in the resting zone stained only faintly for the presence of these growth factors. Some chondrocytes in the resting zone adjacent to the proliferating zone stained with these antibodies, and the antibodies also stained cells in the zone of Ranvier, which regulates latitudinal bone growth. Lastly, the location of transforming growth factor‐β1 was examined further with use of a polyclonal antipeptide antibody specific for its extracellular epitope. Interestingly, extracellular staining for transforming growth factor‐β1 was observed only around chondrocytes in the hypertrophic zone. These results suggest a role for these growth factors in the regulation of proliferation and maturation of chondrocytes and in endochondral ossification.
Frozen storage increases the ultimate compressive load of porcine vertebrae
Authors: Callaghan Jack P. , McGill Stuart M. 
Published: February 2005

AbstractThe use of freezing as a method of storage is commonplace in mechanical testing of biological tissues. The effects of freezing on tissues that comprise spinal segments have been examined separately, but little work has been done on intact specimens. We examined the effect of freezing on the structural properties of porcine cervical spines. The intact cervical spines of seven pigs (a total of 14 specimens–seven of C2–C4 and seven of C5–C7) were stored frozen (−20°C) for 1 month. The ultimate compressive load, displacement, stiffness, and energy absorbed were obtained using a monotonic compressive load applied at 3,000 N/sec. The structural properties were compared with those of another 14 porcine cervical specimens (control group, matched for age and weight) that were tested in a fresh state. The frozen storage of the vertebral specimens significantly increased the ultimate compressive load (24%) and energy absorbed to failure (33%). The stiffness and displacement at failure were not affected. We concluded that the use of freezing as a storage medium should be of concern when the resulting measures are used to quantify the ultimate compressive load of the spinal motion segments.
Regulation of chondrocyte maturation by fibroblast growth factor‐2 and parathyroid hormone
Authors: Iwamoto Masahiro , Shimazu Atsushi , Pacifici Maurizio 
Published: February 2005

AbstractFibroblast growth factor‐2 and parathyroid hormone are strong modulators of the maturation process of chondrocytes during endochondral ossification. To clarify whether and how these agents may exert stage‐specific effects during this process, we analyzed the responsiveness and phenotypic consequences of treatment with fibroblast growth factor‐2 or parathyroid hormone on chondrocytes at different stages of maturation. Populations of immature lower sternal, maturing upper sternal, and hypertrophic tibial growth plate chondrocytes were isolated from day 18–20 chick embryos and were allowed to resume the maturation process by growth in standard monolayer cultures. Treatment of immature lower sternal cultures with as little as 0.1 ng/ml of fibroblast growth factor‐2 or 10−10 M parathyroid hormone prevented both the emergence of mature type‐X collagen‐synthesizing chondrocytes and the ensuing enlargement of cells that occurred in control (untreated) cultures. Similarly, the treatment of cultured early maturing upper sternal cells with these factors severely reduced the synthesis of type‐X collagen and alkaline phosphatase activity and the levels of their respective mRNAs. In sharp contrast, when the cultured upper sternal cells were allowed to grow and mature further before treatment, the responsiveness to fibroblast growth factor‐2 was markedly reduced and the responsiveness to parathyroid hormone remained strong and largely unchanged. Cultures of hypertrophic tibial growth plate cells displayed a similar reduced sensitivity to fibroblast growth factor‐2, as also indicated by the lack of mitogenic effects, and strong sensitivity to parathyroid hormone. The phenotypic changes induced by treatment with either of these factors were fully reversible when cultures that had been treated were placed in control medium. The results demonstrate that fibroblast growth factor‐2 and parathyroid hormone are equally potent in affecting the early stages of maturation but exert differential effects as the cells progress along the maturation pathway. The factors appear to be part of sequentially acting mechanisms to ensure normal progression of chondrocyte maturation during endochondral ossification.