bluuebunny/crossref_metadata_2025_split huggingface dataset:
Age, gender, and bone lamellae elastic moduli
Authors: Hoffler C. E. , Moore K. E. , Kozloff K. , Zysset P. K. , Goldstein S. A. 
Published: February 2005

AbstractTo enhance preventative and therapeutic strategies for metabolic bone diseases and bone fragility disorders, we began to explore the physical properties of bone tissue at the cellular level. Proximal femurs were harvested from 27 cadavera (16 male and 11 female) for in vitro measurement of the mechanical properties. We measured the variations in lamellar‐level elastic modulus and hardness in human bone as a function of age and gender to identify microstructural properties responsible for age and gender‐related reductions in the mechanical integrity. The lateral femoral necks were examined, and age, gender, height, body mass, and body mass index were not found to correlate with lamellar‐level elastic modulus or hardness. This result was consistent for osteonal, interstitial, and trabecular tissue. These data suggest that increased bone mass maintenance, known to occur in heavier individuals, is not accompanied by increases in the lamellar‐level elastic modulus or hardness. The independence of elastic modulus and hardness from age and gender suggests that age and gender‐related decreases in mechanical integrity do not involve alterations in elastic modulus or hard ness of the extracellular matrix. Lamellar‐level ultimate, fatigue, and fracture toughness properties should also be investigated. Other factors, such as tissue mass and organization, may also contribute to age and gender‐related decreases in the mechanical integrity.
Metabolic activity of a new atrophic nonunion model in rabbits
Authors: Brownlow H. C. , Simpson A. H. R. W. 
Published: February 2005

AbstractThe aetiology of atrophic nonunions is not well understood; they are often thought to be nonreactive and metabolically inactive. Investigation of their biological processes is hampered by the lack of a useful animal model. Current models involve either wide segmental excision of the diaphysis or interposition of Silastic to impede the normal healing processes, neither of which resembles the clinical situation. We therefore aimed to establish a model of atrophic nonunion that more closely resembles the clinical situation and to use this model to evaluate the metabolic activity of the gap tissue of the nonunion. A simple and reliable model of atrophic nonunion has been developed in rabbits. It more closely represents the clinical situation by avoiding large segmental excisions and the interposition of foreign materials. Clinical, radiological, and histological data support the diagnosis of atrophic nonunion in the model. The concentration of adenosine triphosphate in the gap tissue of the nonunion served as a marker of metabolic activity. The gap tissue of established atrophic nonunions had a significantly higher concentration of adenosine triphosphate than did the control specimens. In this model, the gap tissue is metabolically active; therefore, under certain conditions, it may be possible to induce union if the correct stimulus is provided.
Cartilage repair with autogenic perichondrium cell/polylactic acid grafts: A two‐year study in rabbits
Authors: Dounchis Jon S. , Coutts Richard D. , Amiel David 
Published: February 2005

AbstractThe repair of articular cartilage injuries remains a challenge. In this 2‐year study, osteochondral defects in the femoral condyles of five rabbits were repaired with an autogenic perichondrium cell/polylactic acid grafts and compared with a contralateral control in which the defect remained empty. The rabbits in the group with the grafts had a higher percentage of biologically acceptable repairs (100%) than did those in the control group (80%). According to the histologic and histomorphometric analyses, the grafts augmented the intrinsic healing. Nonetheless, the results for the grafts were tarnished by a depressed repair surface and a histologic appearance not equivalent to that of normal cartilage. The application of growth factors to this model may yield a clinical treatment.
Migration of cells from human anterior cruciate ligament explants into collagen‐glycosaminoglycan scaffolds
Authors: Murray M. Meaney , Martin S. D. , Spector M. 
Published: February 2005

AbstractRegeneration of the human anterior cruciate ligament after complete rupture offers several theoretical advantages over reconstruction, including maintenance of the complex insertion sites and fan‐shape of the ligament and preservation of remaining proprioceptive fibers within the ligament substance. Well vascularized connective tissues, such as dermis, heal as a result of migration of fibroblasts into a provisional scaffold, the fibrin clot. Wound closure is subsequently facilitated by a contractile cell phenotype. This study was designed to determine if fibroblasts intrinsic to the human anterior cruciate ligament were capable of migrating from their native extracellular matrix onto an adjacent provisional scaffold in vitro. Another objective was to determine whether any of the cells that successfully migrated into the scaffold expressed the contractile actin isoform, α‐smooth muscle actin, associated with wound contraction in other tissues. The results demonstrated that the cells intrinsic to the human anterior cruciate ligament were able to migrate into a collagen‐glycosaminoglycan scaffold, bridging a gap between transected fascicles in vitro. As a result of this cell migration and proliferation, areas in the scaffold contained cell number densities similar to those seen in the human anterior cruciate ligament in vivo. No extracellular matrix or tissue formation was seen in the gap between directly apposed transected ends of the anterior cruciate ligament explants cultured without an interposed collagen‐glycosaminoglycan scaffold. The fascicle‐collagen‐glycosaminoglycan‐fascicle constructs and the fascicle‐fascicle explants displayed minimal adherence after 6 weeks in culture. Any disruption in the contact area between explant and scaffold, even as small a gap as 50 μm, prevented cell migration from the explant to the collagen‐glycosaminoglycan scaffold at the area of loss of contact. All cells that migrated into the scaffold at early time periods expressed the α‐smooth muscle actin isoform. These results demonstrate that cells that migrate into and proliferate within the collagen‐glycosaminoglycan matrix have contractile potential as reflected in their expression of the α‐smooth muscle actin isoform. The role of these contractile cells in the healing process warrants further investigation. Moreover, this study demonstrates the potential of cells intrinsic to the human anterior cruciate ligament to migrate into collagen‐glycosaminoglycan scaffolds that may ultimately be investigated as implants to facilitate ligament healing and regeneration.
Bilateral proprioceptive defects in patients with a unilateral anterior cruciate ligament reconstruction: A comparison between patients and healthy individuals
Authors: Roberts David , Fridén Thomas , Stomberg Anders , Lindstrand Anders , Moritz Ulrich 
Published: February 2005

AbstractProprioception of the knee was measured in 20 patients with reconstructed anterior cruciate ligaments and in 19 age‐matched controls. The mean time from surgery was 2 years. Three tests of proprioception were used: (a) threshold to detection of passive motion from 20 and 40° toward flexion and extension, (b) active reproduction of a 30° passive angle change, and (c) visual reproduction of a 30° passive angle change. The aim was a complete, bilateral, proprioceptive evaluation of patients who had undergone reconstruction of the anterior cruciate ligament. As compared with those in the control group, the knees with reconstructed anterior cruciate ligaments had a higher threshold to detection of passive motion in the extension trials from 20 and 40° (p = 0.0003 and 0.04, respectively) and in the flexion trials from 20 and 40° (p = 0.004 and 0.0008, respectively). When the uninjured knees of the patients were compared with those in the control group, higher values for threshold to detection of passive motion were found in the flexion trials from 20° (p = 0.002) and 40° (p = 0.02). Thus, decreased proprioceptive ability was present in some measurements of these patients after reconstructive surgery, not only in injured knees but also in uninjured knees, as compared with the reference group. The functional relevance of these findings was not investigated in this study, but the results suggest that bilateral proprioceptive considerations should be made when evaluating prognostic factors, treatment, and risk of contralateral knee injury in patients with reconstructed anterior cruciate ligaments.
Comparison and reproducibility of fast and conventional spoiled gradient‐echo magnetic resonance sequences in the determination of knee cartilage volume
Authors: Cicuttini Flavia , Forbes Andrew , Asbeutah Akram , Morris Kevin , Stuckey Stephen 
Published: February 2005

AbstractQuantitation of articular cartilage by magnetic resonance imaging and three‐dimensional reconstruction has been validated and is likely to be a useful outcome measure in clinical trials of arthritis. The cost of magnetic resonance imaging is largely dependent on scanning time. The aim of this study was to compare a fast spoiled gradient‐echo sequence magnetic resonance imaging scanning protocol, which takes 5 minutes and 44 seconds, with the standard, previously validated spoiled gradient‐echo sequence protocol, which takes 11 minutes and 56 seconds, in the measurement of knee cartilage volume. Cartilage volumes calculated from the standard and fast magnetic resonance imaging sequences were similar. The median absolute percentage overestimation or underestimation of the cartilage volume with the fast sequence for 10 normal subjects was 2.5, 4.1, and 3.2% for patellar, femoral, and tibial cartilage, respectively. For eight subjects with osteoarthritis, the percentages were 4.3 and 3.9% for femoral and tibial cartilage, respectively. The fast spoiled gradient‐echo sequence protocol had very high intra‐rater and inter‐rater reproducibility in normal subjects and in those with osteoarthritis. Because the cost of magnetic resonance imaging scanning is largely determined by scan time, the faster scanning protocol means that the cost of estimates of knee cartilage volume can be significantly reduced, thus increasing the feasibility of this methodology.
Spindle‐shaped cells derived from giant‐cell tumor of bone support differentiation of blood monocytes to osteoclast‐like cells
Authors: Miyamoto Noriki , Higuchi Yasumitsu , Tajima Masatoshi , Ito Morihiro , Tsurudome Masato , Nishio Machiko , Kawano Mitsuo , Sudo Akihiro , Uchida Atsumasa , Ito Yasuhiko 
Published: February 2005

AbstractSpindle‐shaped cells were established from four giant‐cell tumors of bone. When human blood monocytes were co‐cultured with these cells, multinucleated giant‐cell formation of monocytes was induced. Intriguingly, even when a filter (pore size: 0.45 μm) was interposed between monocytes and the spindleshaped cells, polykaryocytes also appeared. These multinucleated giant cells were positive for tartrateresistant acid phosphatase, expressed calcitonin receptor, and showed bone‐resorption activity, characteristics of osteoclast‐like cells. These findings indicate that soluble factors secreted from these cells play an important role in osteoclast‐like cell formation from blood monocytes. These data additionally suggest that these cells support osteoclast‐like cell formation in giant‐cell tumors of bone. The cells also expressed mannose receptor, fibronectin, receptor activator of nuclear factorkB, and several cytokine mRNAs, including interleukin‐6, receptor activator of nuclear factorkB ligand/osteoclast differentiation factor/osteoprotegerin ligand, and macrophage colony‐stimulating factor, However, all of these molecules except receptor activator of nuclear factorkB ligand mRNA could also be detected in control HeLa and CV‐1 cells. Although the soluble receptor activator of nuclear factorkB ligand has not been found under physiological conditions, it is possible that it is cleaved by cellular proteases and the truncated receptor activator of nuclear factorkB is released from cells. Identification of the soluble factors capable of inducing osteoclast formation from blood monocytes is a pressing problem to be solved.
Cytokines associated with the pathophysiology of aggressive fibromatosis
Authors: Mills Barbara G. , Frausto Angelica , Brien Earl 
Published: February 2005

AbstractThe rare benign extra‐abdominal desmoid tumor is characterized by aggressive invasion of normal tissue. Treatment is complicated by its recurrence, invasiveness, and persistence. The etiology is unknown and the pathophysiology is obscure. Because of exuberant fibroblastic proliferation with collagenous tissue being the primary tissue component, this desmoid tumor has been compared with keloids arising from excessive scar formation in healing wounds. Numerous cytokines are associated with signaling for growth and maintenance of mesenchymal cells. Altered expression of these proteins is associated with many pathologic conditions. It has been proposed that the enhanced expression of platelet‐derived growth factor and its receptor characterize desmoid tumors. We tested the hypothesis that the exuberant fibrosis of desmoid tumors may have resulted from the initiation of the cascade of molecular events producing increased expression of cytokines. We used immunohistochemical analysis of cytokines in desmoid tumors compared with keloids and skin to localize the expression of cytokines. The results showed localized increased expression of the cytokines epidermal growth factor transforming growth factor‐β, tumor necrosis factor‐α, vascular endothelial growth factor, interleukin‐1β, and interleukin‐6 in the endothelial cells of blood vessels in the tumors. Production of tumor necrosis factor‐α and interleukin‐1β in tumor tissue was increased, but we did not find increased expression of platelet‐derived growth factor. We concluded that the increased expression of cytokines associated with angiogenesis usually found in wound healing and invasive tumors may contribute to the pathophysiology of the desmoid tumor.
Adaptation of post‐traumatic angiogenesis in the rabbit knee by apposition of torn ligament ends
Authors: McDougall Jason J. , Yeung Grace , Leonard Catherine A. , Sutherland Craig , Bray Robert C. 
Published: February 2005

AbstractApposition of torn ligament ends has been shown to have a beneficial effect on healing of the medial collateral ligament; however, the mechanism underlying this improved recovery is unclear. Excessive post‐traumatic angiogenesis, an inherent component of soft‐tissue regeneration, may be functionally detrimental in relatively hypovascular tissues such as ligaments. The present study therefore examined the relationship between contact of transected ligament ends and vascular remodeling. Female New Zealand White rabbits were subjected to a gap injury, Z‐plasty apposition, or sham operation to the midsubstance of the medial collateral ligament. Six weeks after treatment, the volume of vessels supplying the healing zone of the medial collateral ligament, as well as the ipsilateral lateral collateral ligament, posterior cruciate ligament, menisci, and medial capsule, was quantified by carmine red vascular casting. The volume of vessels supplying the neoligamentous scar formed by gap injury to the medial collateral ligament was found to be twice that of ligaments that had undergone the sham operation, and lateral collateral ligament and meniscal vascularity was also augmented in the injured joint. The medial collateral ligaments that underwent Z‐plasty apposition exhibited a level of vascularity comparable with that of the control ligaments that had undergone the sham procedure, whereas meniscal and lateral collateral ligament vascularities remained elevated in this group. Capsular and posterior cruciate ligament vascularities were unaffected by gap injury or Z‐plasty to the ipsilateral medial collateral ligament. These findings indicate that injury to the medial collateral ligament not only stimulates angiogenesis in the healing ligament, but other ipsilateral soft tissues also undergo vascular remodeling. Furthermore, apposition of an injured medial collateral ligament modifies these pro‐angiogenic events, and this may partly explain why contact of torn ligament ends is beneficial for post‐traumatic recovery of an injured joint.
Poroelastic properties of bovine vertebral trabecular bone
Authors: Lim Tae‐Hong , Hong Jung Hwa 
Published: February 2005

AbstractThe theory of poroelasticity has been used to study bone mechanics without directly measuring poroelastic properties. In this study, we developed an experimental protocol and measured the poroelastic properties of bovine vertebral trabecular bone. Mean (±SD) values for drained shear modulus, drained Poisson's ratio, undrained Poisson's ratio, Skempton's coefficient, and permeability coefficient were, respectively, 90.85 (±59.59) MPa and 0.242 (±0.099), 0.399 (±0.083), 0.0851 (±0.144), and 16.31 (±8.02) × 10−8m2/Pa/sec, respectively. The experimental protocol can be used generally for the measurement of poroelastic properties of bone when cylindrical specimens are available. Measured poroelastic properties can be used directly or converted to Biot's coefficient and modulus, without assuming the incompressibility of solid and fluid constituents, for the poroelastic modeling of bone.
Mechanobiology and joint conformity regulate endochondral ossification of sesamoids
Authors: Sarin Vineet K. , Carter Dennis R. 
Published: February 2005

AbstractSesamoid bones form by the endochondral ossification of sesamoid cartilages. This ossification process is thought to be similar to that responsible for the formation of secondary ossific nuclei in long‐bone epiphyses. Sesamoids ossify much later in development than do epiphyses, however, and bone formation within sesamoids often begins by way of multiple ossific nuclei. Endochondral growth and ossification in the formation of secondary ossific nuclei have previously been correlated with distributions of the octahedral shear and hydrostatic stresses generated in vivo within cartilage anlagen. In this study, we used two‐dimensional finite element analysis to predict the distributions of octahedral shear and hydrostatic stresses in an idealized model of a sesamoid cartilage subjected to in vivo loading. We examined the influence of sesamoid joint conformity. The distribution of an osteogenic stimulus was calculated with an approach similar to that used to predict epiphyseal ossification. The results suggest that, compared with conforming joints, nonconformity between the sesamoid cartilage and its articulating surface, which arises during early development, produces higher contact pressures within the sesamoid and leads to a thicker articular cartilage layer. For a nonconforming joint surface, the results suggest that ossification is favored anywhere within a broad internal region of the sesamoid, whereas a layer at the articular surface will remain cartilaginous. These findings highlight the subtle differences between ossification processes in epiphyses and sesamoids, indicating that the mechanical stress environment in sesamoids produces a diffuse stimulus leading to the onset of ossification and that the degree of joint nonconformity may influence the thickness of the articular cartilage layer.
Polysulphated glycosaminoglycan treatments can mitigate decreases in stiffness of articular cartilage in a traumatized animal joint
Authors: Ewers B. J. , Haut R. C. 
Published: February 2005

AbstractA single, blunt impact to the rabbit patellofemoral joint has been shown to decrease the stiffness of retropatellar cartilage and increase the thickness of the underlying bone. Polysulphated glycosaminoglycan treatments, on the other hand, have been shown to inhibit the degradation of articular cartilage and possibly increase synthesis of collagen and glycosaminoglycans in experimental studies on diseased joints. The aim of the current study was to examine the effect of early treatments with polysulphated glycosaminoglycans on cartilage using anin vivopost‐trauma animal model. The study used 24 Flemish Giant rabbits in three groups: control, impacted, and impacted with treatment. Treatment consisted of intramuscular injections the day of insult and every 4 days thereafter for 6 weeks. At 30 weeks after trauma, mechanical tests were performed on the retropatellar cartilage to determine its mechanical stiffness. The patellae were also grossly evaluated for surface lesions on the retropatellar cartilage and histologically processed to measure the thickness of the subchondral bone. The rabbits that received no treatment had a statistically significant decrease in stiffness (modulus) for the cartilage of the impacted patellae compared with that of the contralateral, unimpacted patellae and compared with the cartilage of rabbits in the control group. The degradation in mechanical stiffness, however, was not observed in patellae of rabbits in the group receiving treatment. There was also a significant increase in the underlying thickness of the subchondral plate on the impacted patellae compared with that on the contralateral, unimpacted sides for rabbits in both the treated and nontreated groups. In conclusion, the polysulphated glycosaminoglycan treatments minimized a decrease in mechanical stiffness (modulus) of retropatellar articular cartilage 30 weeks after trauma. The mechanism by which the mechanical stiffness of the cartilage was preserved is unknown.
Mixture of hyaluronic acid and phospholipid prevents adhesion formation on the injured flexor tendon in rabbits
Authors: Moro‐Oka Takaaki , Miura Hiromasa , Mawatari Taro , Kawano Tsutomu , Nakanishi Yoshitaka , Higaki Hidehiko , Iwamoto Yukihide 
Published: February 2005

AbstractDipalmitoyl phosphatidylcholine, a highly surface‐active polar lipid, has been implicated as a potential boundary lubricant for synovial joints. We examined the effects of dipalmitoyl phosphatidylcholine on the flexor tendon and its protective effect against postoperative adhesion in two experimental steps. First, the flexor digitorum fibularis and the distal pulley of rabbits were set for a friction test. The test was performed with saline solution, sodium hyaluronate, or a mixture of dipalmitoyl phosphatidylcholine and sodium hyaluronate as the lubricant. The friction coefficient was significantly lower with the mixture of dipalmitoyl phosphatidylcholine and sodium hyaluronate than with saline solution or sodium hyaluronate. We concluded that the decreased friction coefficient indicates that dipalmitoyl phosphatidylcholine could complement the boundary‐lubricating ability of the tendon. In the second experiment, we used an experimental adhesion model of the flexor digitorum fibularis in the rabbit. During the operation, either saline solution, sodium hyaluronate, or a mixture of dipalmitoyl phosphatidylcholine and sodium hyaluronate was injected into the tendon sheath. The specimen was sent to another tester, and the work required to tear off the adhesion was measured. The work required was significantly greater for the tendons that had been injected with saline solution than for those given injections of dipalmitoyl phosphatidylcholine and sodium hyaluronate. Our findings suggest that dipalmitoyl phosphatidylcholine plays an important role in the boundary lubrication of the tendon and that after tendon injury, the administration of a mixture of dipalmitoyl phosphatidylcholine and sodium hyaluronate may improve tendon lubrication and prevent adhesion formation.