bluuebunny/crossref_metadata_2025_split huggingface dataset:
Chondrocyte survival in cryopreserved osteochondral articular cartilage
Authors: Ohlendorf Christian , Tomford William W. , Mankin Henry J. 
Published: February 2005

AbstractFluorescent staining techniques were used in combination with confocal and conventional fluorescent microscopy to determine the location of viable chondrocytes in frozen and thawed osteochondral articular cartilage. The results showed that cell survival was confined to the superficial layer of the cartilage matrix. The addition of a cryopreservative agent (dimethyl sulfoxide) increased chondrocyte survival but only in the same layer. There was no evidence of cell survival in the middle or deep layers of the cartilage with or without the use of dimethyl sulfoxide. Under the conditions employed in this study, chondrocyte survival in a cryopreserved osteochondral allograft appears to be limited to the superficial layer of the articula cartilage.
In vitro activation of human fibroblasts by retrieved titanium alloy wear debris
Authors: Manlapaz Mariel , Maloney William J. , Smith R. Lane 
Published: February 2005

AbstractTitanium‐aluminum‐vanadium wear particles isolated from the soft‐tissue membrane of a failed total hip arthroplasty were added to human fibroblasts in cell culture. The cellular response to particle challenge was determined by assaying for levels of interleukin‐1β, interleukin‐6, tumor necrosis factor‐α, prostaglandin E2, basic fibroblast growth factor, platelet‐derived growth factor‐AB, and transforming growth factor‐β. Collagenase and gelatinase activities were analyzed by zymography and [3H]collagen degradation. Cell viability was assessed by measuring the uptake of [3H]thymidine. Over the range of particle concentrations tested, cell viability, as demonstrated by [3H]thymidine uptake, remained unaffected. Fibroblasts exhibited a dose‐dependent release of interleukin‐6 in response to exposure to titanium‐aluminum‐vanadium particles. At 6 and 48 hours, the highest concentration of titanium alloy particles (0.189% [vol/vol]) resulted in 7‐fold and 16‐fold increases in interleukin‐6 release, respectively, when compared with negative controls. Neither interleukin‐1β nor tumor necrosis factor‐α was detected in the culture medium at any particle concentration tested for both dermal and foreskin fibroblasts. The pattern of prostaglandin E2 release by fibroblasts mirrored the pattern of interleukin‐6 release. Fibroblasts exposed to the highest concentration of titanium alloy particles showed an increase in collagenase activity, starting at 12 hours. When medium samples were treated with amino phenylmercuric acetate to activate latent enzymes, a statistically significant increase in collagenase activity was observed as early as 6 hours (p < 0.001). Substrate gel analysis of medium from fibroblasts stimulated by high particle concentrations also showed an increase in gelatinolytic activity when compared with unstimulated controls. Analysis of medium samples for growth factors showed an increase in basic fibroblast growth factor at low particle concentrations, beginning at 12 hours. Levels of platelet‐derived growth factor‐AB and transforming growth factor‐β were not detectable in the controls or at any particle concentration tested. The results of this study showed that fibroblasts exposed to titanium alloy wear particles become activated and release proinflammatory mediators that influence bone metabolism. These data support the hypothesis that direct activation of fibroblasts by particulate wear may play a role in particle‐mediated osteolysis. Fibroblast activation coupled with the biologic response of macrophages to wear debris in the loosening membrane may have a synergistic effect on pathologic bone resorption.
Effect of transforming growth factor‐β and platelet‐derived growth factor‐BB on articular cartilage in rats
Authors: Hulth Anders , Johnell Olof , Miyazono Kohei , Lindberg Lisbeth , Heinegård Dick , Heldin Carl‐Henrik 
Published: February 2005

AbstractThe short‐term and long‐term effects on the growth zone in articular cartilage of transforming growth factor‐β1 and platelet‐derived growth factor‐BB injected intraarticularly into the knee joint of growing rats were investigated. The changes induced by five injections of 0.5 μg of transforming growth factor‐β1 included a rapid decrease in the size and number of hypertrophic cells and an enhanced subchondral bone formation. The changes were most marked in the patella but were also apparent in the tibia and femur. The proliferating cells became swollen and lost their normal organization. From the seventh day of the experiment to about 3 weeks, the matrix stained intensely with safranin O for proteoglycans. The alterations induced by transforming growth factor‐β also included synovial fibroplasia and synovitis, consisting predominantly of mononuclear cells. Localised necroses in the cartilage sometimes appeared after 21 days. In long‐term studies, destroyed cartilage was found in three of six rats and partial ossification of the joint cartilage was found in two after 90 and 180 days. Ossicles developed in the tendons in all six patellae. Injection of platelet‐derived growth factor‐BB resulted in an early and transitory minor increase in the osteogenic activity in the zone between cartilage and red bone marrow and later produced an ossicle in one of four tendons. None of the other changes noted after injection of transforming growth factor was observed.
Visualization by magnetic resonance imaging of focal cartilage lesions in the excised mini‐pig knee
Authors: Koh H. L. , Kshirsagar A. , Herrod N. J. , Carpenter T. A. , Hall L. D. , Hunziker E. B. , Tyler J. A. 
Published: February 2005

AbstractThis study showed that magnetic resonance imaging can be used to visualize partial thickness cartilage lesions, 0.7 × 10 mm in area and 0.5 mm in depth, surgically induced in the femur (femoropatellar compartment) of a mini‐pig knee joint. Formalin‐fixed joints, intact as well as disarticulated, were studied by high resolution imaging using a 2.35 T, 31 cm horizontal‐bore superconducting magnet. The two‐dimensional and three‐dimensional spatial resolutions achievable were as follows: 0.12 × 0.23 mm (two‐dimensional) and 0.35 × 0.35 × 0.35 mm (three‐dimensional) for the intact joint, and 0.08 × 0.08 mm (two‐dimensional) and 0.14 × 0.14 × 0.27 mm (three‐dimensional) for the disarticulated joint. These results demonstrate that magnetic resonance imaging, together with edge detection and volume rendering, can be used to visualize focal cartilage lesions.
Optimal normalization tests for shoulder muscle activation: An electromyographic study
Authors: Kelly Bryan T. , Kadrmas Warren R. , Kirkendall Donald T. , Speer Kevin P. 
Published: February 2005

AbstractTo accurately compare electromyographic data from different muscles and different subjects, it is necessary to normalize the integrated data obtained from each muscle. The purpose of this study was to identify the manual muscle testing positions that elicit maximal neural activation (integrated electromyography) of three rotator cuff muscles (supraspinatus, infraspinatus, and subscapularis) and five shoulder synergists (pectoralis major, latissimus dorsi, and anterior, middle, and posterior deltoids). The electromyographic activity of these eight muscles was examined in the nondominant shoulders of nine subjects. Indwelling wire electrodes (supraspinatus, infraspinatus, and subscapularis) and surface adhesive electrodes (pectoralis major, latissimus dorsi, and anterior, middle, and posterior deltoids) were placed. Each subject performed a series of 27 isometric contractions, and optimal tests (maximal neural activation) were identified for each muscle. Four tests were identified that resulted in the maximal neural activation of all eight shoulder muscles: 90° of scapular elevation with −45° of humeral rotation for the supraspinatus, anterior deltoid, and middle deltoid; external rotation at 90° of scapular elevation and −45° of humeral rotation for the infraspinatus and posterior deltoid: internal rotation at 90° of scapular elevation and neutral humeral rotation for the subscapularis and latissimus dorsi: and internal rotation at 0° of elevation and neutral rotation for the pectoralis major. These results identify four standard testing positions that will provide reference values for normalization of maximal voluntary contraction for the eight muscles of the shoulder examined in this study. Standardization of these test positions offers normalization guidelines that can be used in future dynamic electromyography studies of the shoulder.
Alternative splicing of exon 12 of the COL2A1 gene interrupts the triple helix of type‐II collagen in the kniest form of spondyloepiphyseal dysplasia
Authors: Chen Luping , Yang Winnie , Cole William G. 
Published: February 2005

AbstractAn autosomal dominant mutation in the COL2A1 gene was identified in a child with the Kniest form of spondyloepiphyseal dysplasia. A C to T transition at nucleotide 35 of exon 12 changed the codon GCG for alanine 102 of the triple helical domain of α1 (II) chains of type‐II collagen to GTG for valine. The transition also introduced a GT dinucleotide into exon 12. Analysis of cDNA prepared from Kniest cartilage showed that in vivo the transition resulted in an alternatively spliced mRNA that lacked the 21 3′ nucleotides from exon 12. The cartilage cDNA contained approximately equal amounts of normal cDNA and shortened mutant cDNA. The deletion of 21 nucleotides from the mutant cDNA maintained the translational reading frame but resulted in the loss of alanine 102 to lysine 108, which interrupted the repetitive glycine‐X‐Y triplet sequence required for formation of the triple helix. Type‐II collagen molecules containing one or more mutant chains were expected, therefore, to contain interrupted triple helices with a short amino‐terminal helical domain A and a large carboxy‐terminal helical domain B. Kniest cartilage contained a reduced amount of pepsin‐solubilized type‐II collagen that consisted of overmodified α1 (II) chains. Peptide mapping showed that the overmodifications extended to the carboxy terminus of the α1(II) chains. Pepsin digestion also yielded shortened α1 (II) chains corresponding to helical domain B, Kniest chondrocytes cultured in alginate beads produced type‐II collagen that was not stably incorporated into the pericellular matrix. This study highlights the importance of dominant negative mutations of COL2A1 in producing Kniest dysplasia.
Regulation of proliferation and platelet‐derived growth factor expression in palmar fibromatosis (Dupuytren contracture) by mechanical strain
Authors: Alman Benjamin A. , Greel Debra A. , Ruby Leonard K. , Goldberg Michael J. , Wolfe Hubert J. 
Published: February 2005

AbstractPalmar fibromatosis (Dupuytren contracture) causes fibrosis of specific palmar fascial bands. These bands are subjected to repetitive mechanical strain in situ. Primary cell cultures were derived from (a) palmar fibromatosis from eight patients, (b) uninvolved palmar fascia (Skoog's fibers) from four of these patients and (c) normal palmar fascia from four additional patients. The cells were plated onto collagen‐coated membranes either subjected to cyclic strain (25% maximal strain at 1 Hz) or without strain. Bromodeoxy uridine incorporation showed an increase in proliferation in all cultures subjected to strain. This increase was highest for palmar fibromatosis (10 to 40% nuclear incorporation, p = 0.02). Skoog's fibers and fascia from the normal individuals showed a trend (not significant) toward increase with strain (8 to 25%, p = 0.15 for Skoog's fibers, and 8 to 15%, p = 0.45 for normal fascia). Cyclic strain increased the expression of platelet derived growth factor‐A relative to glyceraldehyde‐3‐phosphate dehydrogenase in palmar fibromatosis (2.2 to 3.5, p = 0.05) and Skoog's fibers (0.8 to 2.0, p = 0.04). The expression of platelet‐derived growth factor‐B relative to glyceraldehyde‐3‐phosphate dehydrogenase was enhanced by cyclic strain only in the fibromatosis tissue (0.7 to 2.1, p = 0.04). The normal fascia did not express platelet‐derived growth factor. Platelet‐derived growth factor neutralizing antibody decreased bromodeoxyuridine incorporation in fibromatosis cultures subjected to cyclic strain to near levels for those grown in the absence of strain (38 to 16%, p = 0.05). Conditioned medium from fibromatosis cells grown under stain showed a trend toward increased proliferation in additional fibromatosis cultures compared with conditioned medium from fibromatosis cells grown without strain (9 to 15% nuclear incorporation, p = 0.20). The observed palmar fibromatosis contracture can be partially explained on the basis of the cell's response to cyclic strain, which may be mediated by plateletderived growth factor.
Gentamicin distribution from a collagen carrier
Authors: Mehta Sanjay , Humphrey J. Stewart , Schenkman Daniel I. , Seaber Anthony V. , Vail Thomas Parker 
Published: February 2005

AbstractLocal delivery of antibiotics by a degradable carrier has the potential for high local antibiotic levels and avoids systemic toxicity. Intravenous access, renal function monitoring, and subsequent surgical removal may not be required when degradable local delivery modalities are used. This study examined the in vivo elution of gentamicin from processed bovine collagen (type I) in 66 adult White rabbits. Collagen impregnated with gentamicin (3 mg/kg) was implanted into the vastus lateralis, and data were collected from 15 minutes to 28 days after implantation. Local tissue biopsies were taken a minimum of 2 mm from the implantation site. The gentamicin was released into the local tissue and averaged more than 3,800 μg/ml during the initial 4 hours after implantation. Local levels fell to 6.90 ± 5.22 μg/ml at 24 hours and subse‐quently were 2.70 ± 1.75. μg/ml or more through day 28. Serum levels reached an average peak of 4.04 ± 1.75 μg/ml at 5 hours after implantation, decreased after the initial 24 hours, and subsequently were less than 0.41 ± 0.20 μg/ml through day 28. Collagen impregnated with gentamicin proved to be an effective degradable carrier of gentamicin in the healthy rabbit; it provided local tissue concentrations above the minimum inhibitory concentration and serum concentrations below levels associated with systemic toxicity for 28 days after implantation.
Calculated stress‐shielding in the distal femur after total knee replacement corresponds to the reported location of bone loss
Authors: Tissakht M. , Ahmed A. M. , Chan K. C. 
Published: February 2005

AbstractThis study sought to determine the similarities between features of calculated stress‐shielding and observed bone loss in the distal femur after total knee replacement. Stress‐shielding was determined by comparing the magnitudes and distributions of strain energy density, calculated using three‐dimensional finite element models of the intact bone, the bone after total knee replacement with bonding assumed at all prosthesis‐bone interfaces, and the bone after total knee replacement with bonding assumed only at the distal interface. The loading condition simulated static lifting with the knee flexed at 45°, producing tibiofemoral and patellofemoral joint reactions of 900 and 450 N, respectively. The maximum magnitudes of strain energy density calculated using the total knee replacement models were less than 15% of the corresponding magnitudes from the intact bone model. The greatest difference was found to occur at the anterior distal corner of the femur, suggesting this location as the one most vulnerable to stress‐shielding. Clinically observed bone loss after total knee replacement frequently occurs at this location. At the anterior distal corner, the calculated magnitudes for the two total knee replacement models were similar, suggesting that stress‐shielding at this location was not reduced by limiting fixation only to the distal interface. Although the study corresponded to one loading condition and one geometry of the total knee replacement femoral component with the inherent limitations of model calculations, the results suggest a possible scenario for stress‐shielding.
Augmentation of femoral neck fracture fixation with an injectable calcium‐phosphate bone mineral cement
Authors: Stankewich C. J. , Swiontkowski Marc F. , Tencer Allan F. , Yetkinler Duran N. , Poser Robert D. 
Published: February 2005

AbstractThe first goal of this study was to determine if augmentation with an injectable, in situ setting, calcium‐phosphate cement that is capable of being remodeled and was designed to mimic bone mineral significantly improved the strength and stiffness of fixation in a cadaveric femoral neck fracture model. The second goal was to determine if greater increases in fixation strength were achieved as the bone density of the specimen decreased. Sixteen pairs of fresh cadaveric human femora with a mean age of 70.9 years (SD = 17.2 years) were utilized. The bone density of the femoral neck was measured with dual‐energy x‐ray absorptiometry. The femoral head was impacted vertically with the femoral shaft fixed in 12° of adduction using a materials testing machine to create a fully displaced fracture. Following fracture, 30% inferior comminution was created in each specimen. One randomly chosen femur from each pair underwent anatomic reduction and fixation with three cannulated cancellous bone screws, 7 mm in diameter, in an inverted triangle configuration. The contralateral femur underwent the same fixation augmented with calcium‐phosphate cement. Specimens were preconditioned followed by 1,000 cycles to one body weight (611.6 N) at 0.5 Hz to simulate single‐limb stance loading. The stiffness in the first cycle was observed to be significantly greater in cement‐augmented specimens compared with unaugmented controls (p < 0.05). After cycling, each specimen was loaded at 10 mm/min until complete displacement of the fracture surface and failure of fixation occurred. Specimens augmented with bone mineral cement failed at a mean of 4,573 N (SD = 1,243 N); this was significantly greater (p < 0.01) than the mean for controls (3,092 N, SD = 1,258 N). The relative improvement in fixation strength (augmented/control × 100% ) was not inversely correlated to femoral neck bone density (p = 0.25, R2 = 0.09), was weakly correlated to the volume of cement injected (p = 0.07, R2 = 0.22), and was inversely related to the fixation failure load of the control specimen (p = 0.001, R2 = 0.54). There was a mean relative improvement in fixation strength of 169.6% (SD = 77.5). These findings suggest that calcium‐phosphate cement provides initial beneficial augmentation to fixation of femoral neck fractures.
Distribution of elastic fiber types in the epiphyseal region
Authors: Gigante A. , Greco F. , Specchia N. , Nori S. 
Published: February 2005

AbstractThree types of elastic fibers have been described: mature elastic fibers, elaunin fibers, and oxytalan fibers. To our knowledge, their location in the immature epiphysis has never been previously reported. The aim of the present study was to use histochemistry, immunohistochemistry, and electron microscopy to demonstrate the distribution of each type of elastic fiber in the epiphyseal region of growing humans and rabbits. Histological samples were collected from the knees of 10 immature New Zealand White rabbits and four children of various ages. The Weigert resorcin‐fuchsin, Gomori aldehyde‐fuchsin, Verhoeff iron haematoxylin, and Fullmer‐Lillie methods were used for histochemistry; anti‐elastin monoclonal antibodies, for immunohistochemistry; and tannic acid, uranyl acetate, and lead citrate stain, for transmission electron microscopy analysis. Elastic fibers were detected in the perichondrium, the epiphyseal vessels, and the outer and middle zones of Ranvier's groove. Their orientation was longitudinal in the outer zone and circumferential in the middle zone of the groove. Oxytalan fibrils (i.e., bundles of filaments of 10–12 nm in diameter that do not contain elastin) and elaunin fibers (i.e., filaments that cross discontinuous aggregates of elastin) were more plentiful in the middle zone and decreased with age, whereas mature fibers were more numerous in the outer zone and increased with age. This organization of elastic fibers seems to indicate an age‐related process of maturation of the elastic network. The contribution of these fibers to the mechanical properties of the epiphyseal plate and to the growth process remains to be determined.
Protective effect of 21‐aminosteroid pretreatment in peripheral nerve low‐load crush injury in mature and immature rats
Authors: Nasser Rima M. , Chen Long‐En , Seaber Anthony V. , Urbaniak James R. 
Published: February 2005

AbstractThe effects of U‐74006F (tirilazad mesylate), a 21‐aminosterold antioxidant, on injured peripheral nerve were studied. Twenty‐two immature and 44 mature rats were divided equally into two groups. The experimental group received two injections of 3 mg/kg of U‐74006F at a 2 hour interval. The control group received the same volumes of a citrate buffer. A 5 mm segment of the sciatic nerve was subjected to a crush load of 100 g for 2 hours. Motor function (sciatic functional index) was assessed to day 48 postoperatively. There was total paralysis of the crushed limb in all rats the first week after crushing. The experimental group had a statistically significant improvement in motor function compared with the controls on days 14, 21, 25, and 28 for the mature rats and on days 11 and 14 for the immature rats. The mature controls attained complete recovery on day 42 and had a significantly slower recovery rate than the immature controls, which had recovered fully by day 25. The recovery rates were almost similar among mature and immature groups pretreated with U‐74006F, both of which had fully recovered motor function by day 28. The results indicate that pretreatment with U‐74006F can significantly promote peripheral nerve function after low‐load crush injury and that the age of the animal influences the rate of peripheral nerve recovery.
Tensile properties of the interosseous membrane of the human forearm
Authors: Pfaeffle H. James , Tomaino Matthew M. , Grewal Rupinder , Xu Jiangming , Boardman N. Douglas , Woo Savio L‐Y. , Herndon James H. 
Published: February 2005

AbstractThe interosseous membrane is a structure deep in the forearm that joins the radius and the ulna. It is made up of membranous and ligamentous regions. Two main ligamentous structures have been described: a prominent central fiber group, the “central band,” and a smaller proximal fibrous band, the “oblique cord.” Many authors believe that the central band plays a biomechanical role in the normal and fractured forearm and that it may function much like a ligament. The objective of this study was to determine the tensile properties of the central band. Eighteen fresh frozen forearms from cadavers (45–70 years of age, both sexes) were used. A fiber bundle of the central band was subjected to a uniaxial tensile test to failure in a materials testing machine, and its tensile properties were calculated. Stiffness, ultimate load, and energy absorbed to failure were expressed as a function of specimen width. The central band structure had a stiffness of 13.1 ± 3.0 N/mm per mm width and an ultimate load of 56.6 ± 15.1 N per mm width (mean ± SD). The tissue of the central band displayed a modulus of 608.1 ± 160.2 MPa, ultimate tensile strength of 45.1 ± 10.3 MPa, and strain at failure of 9.0 ± 2.0%. This study demonstrated that the central band is comprised of strong tissue. The material properties of the central band compare with those of patellar tendon: modulus is 120% and ultimate tensile strength is 84% that of patellar tendon. As a structure, the interosseous membrane is stiff and capable of bearing high loads. Although load distribution across the central band is unknown, a 1.7 cm wide, evenly loaded homogenous portion of the central band would possess a stiffness comparable with that of the anterior cruciate ligament. The results of this study provide a basis for future analyses of radioulnar stability and load transfer.