bluuebunny/crossref_metadata_2025_split huggingface dataset:
In situ force distribution in the glenohumeral joint capsule during anterior‐posterior loading
Authors: Debski Richard E. , Wong Eric K. , Woo Savio L‐Y. , Sakane Masataka , Fu Freddie H. , Warner Jon J. P. 
Published: February 2005

AbstractOur objective was to examine the function of the glenohumeral capsule and ligaments during application of an anterior‐posterior load by directly measuring the in situ force distribution in these structures as well as the compliance of the joint. We hypothesized that interaction between different regions of the capsule due to its continuous nature results in a complex force distribution throughout the glenohumeral joint capsule. A robotic/universal force‐moment sensor testing system was utilized to determine the force distribution in the glenohumeral capsule and ligaments of intact shoulder specimens and the joint kinematics resulting from the application of external loads at four abduction angles. Our results suggest that the glenohumeral capsule carries no force when the humeral head is centered in the glenoid with the humerus in anatomic rotation. However, once an anterior‐posterior load is applied to the joint, the glenohumeral ligaments carry force (during anterior loading, the superior glenohumeral‐coracohumeral ligaments carried 26 ± 16 N at 0° and the anterior band of the inferior glenohumeral ligament carried 30 ± 21 N at 90°). Therefore, the patient's ability to use the arm with the humerus in anatomic rotation should not be limited following repair procedures for shoulder instability because the repaired capsuloligamentous structures should not carry force during this motion. Separation of the capsule into its components revealed that forces are being transmitted between each region and that the glenohumeral ligaments do not act as traditional ligaments that carry a pure tensile force along their length. The interrelationship of the glenohumeral ligaments forms the biomechanical basis for the capsular shift procedure. The compliance of the joint under our loading conditions indicates that the passive properties of the capsule provide little resistance to motion of the humerus during 10 mm of anterior or posterior translation with anatomic humeral rotation. Finally, this knowledge also enchances the understanding of arm positioning relative to the portion of the glenohumeral capsule that limits translation during examination under anesthesia.
Contrast‐enhanced magnetic resonance imaging in a nontraumatic rabbit osteonecrosis model
Authors: Sakai Takashi , Sugano Nobuhiko , Tsuji Takashi , Miyazawa Tomoaki , Nakamura Nobuo , Haraguchi Keiji , Ochi Takahiro , Ohzono Kenji 
Published: February 2005

AbstractWe investigated early osteonecrosis using in vivo magnetic resonance imaging in a nontraumatic rabbit model of serum‐sickness osteonecrosis in which osteonecrosis was induced after two intravenous injections of horse serum with a 3‐week interval. One week (group A, 17 rabbits) and 3 weeks (group B, 13 rabbits) after the second serum injection coronal magnetic resonance images of the femur were obtained and it was removed for histological study. Some of the necrotic lesions in the diaphysis were detected on T1‐weighted, T2‐weighted, or fat‐suppression T1‐weighted images (six of 24 necrotic lesions in group A and 16 of 18 in group B), and all of the necrotic lesions in the epiphysis, metaphysis, and diaphysis were detected on T1‐weighted or fat‐suppression T1‐weighted images enhanced with gadolinium‐diethylene triamine penta‐acetic acid. All focal homogeneous enhanced areas on T1‐weighted or fat suppression T1‐weighted images corresponded to necrotic lesions (22 of 24 necrotic lesions in group A and 18 of 18 in group B); the contours of the enhanced areas were displayed more clearly on the fat‐suppression T1‐weighted than on the T1‐weighted images. The fat‐suppression T1‐weighted image enhanced with gadolinium‐diethylene triamine pentaacetic acid was thus the most sensitive and specific of five kinds of magnetic resonance images for the detection of early necrotic lesions. The results suggest that this image may be useful for early diagnosis of clinical osteonecrosis and for obtaining information about the pathomechanism of osteonecrosis.
Measurement and removal of adherent endotoxin from titanium particles and implant surfaces
Authors: Ragab Ashraf A , Van De Motter Renee , Lavish Sandra A. , Goldberg Victor M. , Ninomiya James T. , Carlin Cathleen R. , Greenfield Edward M. 
Published: February 2005

AbstractAseptic loosening is thought to be due primarily to osteolysis induced by cytokines and prostaglandins that are produced in response to implant‐derived wear particles. Because endotoxin has many of the same effects as have been reported for wear particles, we hypothesized that adherent endotoxin may be responsible for the biological responses induced by wear particles. We demonstrated the presence of significant levels of adherent endotoxin on commonly used preparations of titanium particles as well as on titanium and titanium‐alloy implant surfaces. In contrast, supernatants obtained by centrifugation of particle suspensions contained approximately 1% as much endotoxin as did the particles. Therefore, it is erroneous to assume that particles do not contain endotoxin on the basis of data that it cannot be detected in their supernatants or filtrates. These results emphasize the importance of considering the potential role of adherent endotoxin when examining the in vitro effects of wear particles and the in vivo performance of orthopaedic implants. We also developed a protocol that removed more than 99.94% of the adherent endotoxin from the titanium particles without detectably affecting their size or shape. The removal of adherent endotoxin will allow comparison of the biological responses induced by particles with or without adherent endotoxin.
Integrative cartilage repair: Inhibition by β‐aminopropionitrile
Authors: Ahsan Tabassum , Lottman Lisa M. , Harwood Fred , Amiel David , Sah Robert L. 
Published: February 2005

AbstractThe effects of β‐aminopropionitrile, a known inhibitor of lysyl oxidase, on the extractability of newly synthesized collagen and integrative cartilage repair were determined in explant cultures of adult bovine articular cartilage. Dose‐escalation studies indicated that treatment of cartilage explants for 6 days with β‐aminopropionitrile caused a dose‐dependent inhibition of proteoglycan synthesis ([35S]sulfate incorporation) with a 50% inhibition at 2.2 mM. However, 0.25 mM β‐aminopropionitrile had no detectable effect on proteoglycan synthesis and was thus used for subsequent experiments. Treatment of cartilage with β‐aminopropionitrile for 14 days increased the extractability of newly synthesized collagen with 4 M guanidine‐HCI while having little effect on proteoglycan synthesis, proteoglycan deposition, or cartilage cellularity (DNA content). In untreated cultures, the percentage of radiolabeled collagen ([3H]hydroxyproline) that was extractable after 1 day of radiolabeling, 6 days of radiolabeling, or 6 days of label and 6 days of chase decreased from 81 to 25 and 9%, respectively. In β‐aminopropionitrile‐treated cultures, the extractability was relatively higher (96, 62, and 47%, respectively). Treatment with β‐aminopropionitrile after radiolabeling with [14C]lysine also significantly inhibited the formation of the reducible crosslink [14C]dihydroxylysinonorleucine without affecting the overall deposition in cartilage of [14C]lysine and [14C]hydroxylysine. In functional repair studies, treatment with β‐aminopropionitrile caused an almost complete inhibition of integration between pairs of cartilage explants maintained in apposition for 2 weeks. These results indicate that β‐aminopropionitrile blocks the formation of collagen crosslinks in cartilage explants and suggest that such crosslinks are critical to integrative cartilage repair.
Hyaluronan suppresses fibronectin fragment‐mediated damage to human cartilage explant cultures by enhancing proteoglycan synthesis
Authors: Kang Yong , Eger Wolfgang , Koepp Holger , Williams James M. , Kuettner Klaus E. , Homandberg Gene A. 
Published: February 2005

AbstractHyaluronic acid, recently renamed hyaluronan, has been used as a therapeutic intervention in the treatment of osteoarthritis. We have reported that high‐molecular‐weight (800 kDa) hyaluronan is effective in blocking the catabolic action of fibronectin fragments in explant cultures of bovine cartilage and in an experimentalin vivomodel of damage to the rabbit knee joint. The fibronectin fragments induce catabolic cytokines in human cartilage, which, in turn, suppress proteoglycan synthesis and induce matrix metalloproteinases to decrease the proteoglycan content. Since the clinical target of high‐molecular‐weight hyaluronan is human cartilage, which may differ in certain ways from bovine cartilage, we tested the effect on human knee cartilage. We found that 1 mg/ml hyaluronan completely blocked fibronectin fragment‐mediated decreases in proteoglycan content in five of five specimens of cartilage from the human knee. This was associated with binding of exogenous hyaluronan to the superficial surface, suppressed penetration of the fibronectin fragment into the cartilage, decreased expression for the first week in culture of one of the matrix metalloproteinases involved in cartilage degradation, matrix metalloproteinase‐3, and proteoglycan synthesis rates that increased to supernormal levels. However, the appearance of the NITEGE and VDIPEN neoepitopes, indices of cartilage degradation, was not blocked but was delayed by 1 week. The addition of hyaluronan to cartilage previously damaged by the fibronectin fragments or to osteoarthritic cartilage fully restored the proteoglycan content to control levels. We conclude that hyaluronan blocked damage at least partly by blocking penetration of the fibronectin fragments and slowing matrix metalloproteinase expression. However, the major effect on blocking damage and promoting repair may be through enhanced proteoglycan synthesis, a mechanism that requires further study. Nonetheless, these data clearly demonstrate that hyaluronan completely protected human cartilage in explant culture and facilitated a full restoration of proteoglycan in damaged cartilage.
Transplantation of cryopreserved osteochondral dowel allografts for repair of focal articular defects in an ovine model
Authors: Schachar Norman S. , Novak Kelli , Hurtig Mark , Muldrew Ken , McPherson Roger , Wohl Greg , Zernicke Ronald F. , McGann Locksley E. 
Published: February 2005

AbstractThe purpose of this study was to test whether successful cryopreservation of osteochondral tissue is possible and whether, with the appropriate surgical procedure, it can be used for the successful repair of focal articular defects within joints. Fresh (nonfrozen) and snap‐frozen (plunged in liquid nitrogen and thawed in a water bath at 37°C, repeated three times) autografts were used as positive and negative controls, respectively. Snap‐frozen, frozen (fresh tissue placed in a freezer at −80°C), and cryopreserved (immersed in 10% dimethyl sulfoxide for 30 minutes and then frozen at 1°C/min to −80°C) allografts were transplanted into the knees of adult sheep. Outcomes were evaluated 3, 6, and 12 months after transplantation. The morphological, histological, biochemical, and biomechanical behaviors and characteristics of the graft cartilage, the host cartilage adjacent to the grafts, and the opposing tibial cartilage were assessed. Freezing protocols that yielded poor chondrocyte recovery after thawing (frozen and snap‐frozen) resulted in poor overall graft outcome. The cryopreservation protocol, however, resulted in intermediate recovery (50%) of chondrocytes and in intermediate overall graft outcome compared with fresh autografts. The membrane integrity of the allograft chondrocytes immediately following cryopreservation was identified as the most reliable predictor of long‐term outcome of the graft. Further improvements in cryopreservation technique may lead to an effective method of banking osteochondral tissue for successful transplantation for the repair of focal defects and larger joint reconstructions.
Multidrug resistance‐1 and p‐glycoprotein in human chondrosarcoma cell lines: Expression correlates with decreased intracellular doxorubicin and in vitro chemoresistance
Authors: Wyman James J. , Hornstein Abby M. , Meitner Patricia A. , Mak Solida , Verdier Patrick , Block Joel A. , Pan J. , Terek Richard M. 
Published: February 2005

AbstractWe report on two chondrosarcoma cell lines, FS and AQ, that may be used as models of multidrug resistance in chondrosarcoma. Multidrug resistance‐1 expression was assayed with reverse transcription‐polymerase chain reaction. Immunostaining for the multidrug resistance‐1 product, P‐glycoprotein, was performed with the monoclonal antibody C494. Intracellular levels of doxorubicin were measured by fluorescent emission at 590 nm after 1 hour of incubation with the agent and again after 1, 2, and 4‐hour washout periods. Chemosensitivity was assayed by staining micropellet cultures of AQ and FS cells with fluorescein acetate before and after the cells were exposed to varying doses of doxorubicin for 48 hours. Cytotoxicity was assessed by comparison of computer‐processed images before and after treatment. The FS cell line was positive for multidrug resistance‐1 expression, stained heavily for P‐glycoprotein, and had significantly lower intracellular levels of doxorubicin than the AQ cell line, which was negative for multidrug resistance‐1 and P‐glycoprotein. Chemosensitivity testing showed that the FS cell line was significantly more resistant to doxorubicin than was the AQ cell line at all doses tested. Our results show that multidrug resistance‐1 expression in a human chondrosarcoma cell line results in resistance to doxorubicin in vitro.
mRNA expression of interleukins, phospholipase A2, and nitric oxide synthase in the nerve root and dorsal root ganglion induced by autologous nucleus pulposus in the rat
Authors: Kawakami Mamoru , Matsumoto Takuji , Kuribayashi Koichi , Tamaki Tetsuya 
Published: February 2005

AbstractThe purpose of this study was to examine whether mRNA of interleukin‐1β, interleukin‐6, phospholipase A2, and nitric oxide synthase was expressed in the nerve root and dorsal root ganglion of an animal model in which exposure to the nucleus pulposus induced mechanical hyperalgesia, a pain‐related behavior. Autologous nucleus pulposus obtained from coccygeal discs was relocated on the L4 and L5 lumbar nerve roots after partial laminectomy. The reflex response to noxious mechanical stimuli to the hindpaw was measured preoperatively and to 4 weeks postoperatively. With a reverse transcription‐polymerase chain reaction technique, expression of interleukin‐1β, interleukin‐6, phospholipase A2, and inducible nitric oxide synthase genes in the nerve root and dorsal root ganglion was observed at 1, 2, and 4 weeks postoperatively. Mechanical hyperalgesia was observed from 3 days to 2 weeks postoperatively. The expression of interleukin‐1β, phospholipase A2, and inducible nitric oxide synthase mRNAs increased after only 1 week. This increase was related to mechanical hyperalgesia. Expression of interleukin‐6 was detected in the neural tissue over time. It is possible that interleukin‐1β, phospholipase A2, and inducible nitric oxide in the nerve root or dorsal root ganglion, or in both, produce sciatic pain in the early stage of herniation of the lumbar disc.
Contamination of the medullary canal following pin‐tract infection
Authors: Clasper J. C. , Parker S. J. , Simpson A. H. R. W. , Watkins P. E. 
Published: February 2005

AbstractWe developed an ovine model of an external‐fixator pin‐tract infection. With use of a novel method of tissue sampling, infection of the medullary canal was confirmed in all (10 of 10) external‐fixator pins that were contaminated with Staphylococcus aureus after they were inserted. In addition, all (five of five) adjacent, uncontaminated pins became infected. We demonstrated that pin‐tract infection can be difficult to diagnose clinically, despite gross infection of the tract, and that bacteria can spread within the medulla. Three of the infected pins (20%) did not appear clinically infected, were not loose, and were normal on radiographs after 1 week. Staphylococcus aureus was isolated from the medulla around all 15 pin tracts, and nine other organisms were isolated from the tracts. Despite the presence of infection, the majority of the pins remained well fixed in the bone after 2 weeks.
Drug‐induced apoptosis in osteosarcoma cell lines is mediated by caspase activation independent of CD95‐receptor/ligand interaction
Authors: Fellenberg J. , Mau H. , Nedel S. , Ewerbeck V. , Debatin K‐M. 
Published: February 2005

AbstractOsteosarcoma is one of the most common primary malignant tumors of bone. Treatment of this tumor with systemic chemotherapy dramatically improves the prognosis, although the molecular mechanisms involved in the drug action are poorly understood. In chemosensitive leukaemic T cells and certain solid tumors. cytotoxic drugs mediate the induction of apoptosis by activation of the CD95/APO‐1/Fas system. Triggering of the corresponding signaling pathway may involve CD95‐receptor/ligand interaction, activation of caspases, or alterations in mitochondrial function. The purpose of our study was to determine if similar mechanisms are involved in the chemosensitivity of osteosarcomas. We found that cytotoxic drugs induce characteristic biochemical and morphological alterations related to apoptosis in osteosarcoma cell lines, including activation of caspases and disturbance of mitochondrial function. However, drug treatment did not result in activation of CD95‐receptor or CD95‐ligand mRNA. In addition, drug‐induced apoptosis was blocked by caspase inhibitors but not by inhibition of CD95‐ligand action, indicating a CD95‐receptor/ligand‐independent mechanism in osteosarcoma cell lines.
Cellular responses of embryonic hyaline cartilage to experimental wounding in vitro
Authors: Walker E. A. , Verner A. , Flannery C. R. , Archer C. W. 
Published: February 2005

AbstractIt is well established that the reparative potential of many tissues is greatest during embryonic development. Despite the extensive literature documenting repair in nonembryonic cartilage models, there is no comparable wealth of experience relating to embryonic cartilage repair. With the embryonic chick sternum as a model of hyaline cartilage, this paper accounts cellular responses and alterations in extracellulat matrix composition in response to experimental wounding in vitro. Creation of an experimental lesion induced a rapid (<20 minutes) apoptotic response in chondrocytes adjacent to the lesion edge; the presence of perichondrium delayed this response. Alterations in the extracellular matrix included immediate mechanical damage to type‐II collagen fibrils and an increase in the expression of chondroitin‐4 sulphate next to the lesion. Creation of the lesion induced an increased proliferative response in chondrocytes behind the zone of apoptosis and the expression of α5 and α6 integrin subunits.
Comparison of three methods of gluteal muscle attachment to an allograft/endoprosthetic composite in a canine model
Authors: Pluhar G. Elizabeth , Heiner John P. , Manley Paul A. , Bogdanske John J. , Vanderby Ray , Markel Mark D. 
Published: February 2005

AbstractThis study used radiography, gait analysis, gluteal muscle mass, mechanical testing, and qualitative histology to compare three methods of gluteal muscle attachment to an allograft/endoprosthetic composite of the proximal 25% of the femur in anin vivocanine model. The three methods of gluteal muscle attachment were identical to those used clinically in human patients for hip revision and proximal femoral limb salvage: the host gluteal tendon sutured to the allograft tendon (tendon group), the host greater trochanter with intact gluteal tendons secured to the allograft with a cable‐grip system (grip group), and periosteally vascularized proximal femoral bone onlay with intact tendons wrapped around the allograft (wrap group). On the basis of radiographs taken every 2 months, the tendon group had more graft fractures than did the grip or wrap group. Radiographic union of the graft‐host bone junction occurred more rapidly and there was less graft resorption in the wrap group than in the other two groups. In all dogs, peak vertical ground‐reaction forces in the treated limb decreased immediately after surgery and then slowly increased over the length of the study. The dogs in the wrap group regained normal weight‐bearing on the treated limb more quickly than did those in the other groups. The constructs in the tendon group were weaker and less stiff immediately after surgery than were those in the other groups or in intact controls. Histologic analysis confirmed that the wrap technique resulted in complete union of the host bone‐allograft junction more often than did the other techniques. The wrap method had the best functional outcome after 9 months when an allograft/endoprosthetic composite was used during total hip arthroplasty in this canine model.
Collagen crosslinked N‐telopeptides as markers for evaluating particulate osteolysis: A preliminary study
Authors: Antoniou John , Huk Olga , Zukor David , Eyre David , Alini Mauro 
Published: February 2005

AbstractThe purpose of this study was to determine whether a marker of bone resorption could be used noninvasively to diagnose and assess treatment of periprosthetic osteolysis. The crosslinked N‐telopeptide marker of osteoclast‐mediated bone resorption potentially has the sensitivity to detect periprosthetic osteolysis. Second‐morning urine specimens were obtained from (a) seven age‐matched controls, (b) eight patients who had a hip arthroplasty, hybrid implants at least 1 year after surgery, and no osteolysis, (c) 11 patients who had a hip arthroplasty and osteolysis, and (d) 10 patients who had a hip arthroplasty and with osteolysis before and after 6 weeks of oral Fosamax (alendronate) treatment. The Fosamax treatment consisted of one 10‐mg dose per day for 6 weeks. Men and young women (less than 40 years old) were chosen for this study to avoid bone resorption enhanced after menopause as a possible confounder. An enzyme‐linked immunosorbent assay technique for quantifying crosslinked N‐telopeptides of type‐I collagen was performed on all specimens. The patients with osteolysis had significantly elevated levels of N‐telopeptide compared with the implant control group. In addition, levels of N‐telopeptide were significantly lowered after Fosamax treatment. These findings indicate that a systemic bone‐resorption marker (N‐telopeptide) can be used to evaluate local particulate‐induced osteolysis and its treatment. The study also provides clinical evidence that osteolysis is associated with increased osteoclast‐mediated bone resorption and that this locally induced bone resorption can be suppressed by certain bisphosphonates (Fosamax). These insights have potential value in the understanding and clinical management of aseptic loosening.