bluuebunny/crossref_metadata_2025_split huggingface dataset:
Digital examination compared to trans‐perineal ultrasound for the evaluation of anal sphincter repair
Authors: Shobeiri S.A. , Nolan T.E. , Yordan‐Jovet R. , Echols K.T. , Chesson R.R. 
Published: October 2002

AbstractObjective: To assess the adequacy of a third‐ or a fourth‐degree laceration repair by comparing digital and trans‐perineal ultrasound measurements. Method: During a 4‐year period, 34 subjects without prior history of anal sphincter injury or fecal incontinence underwent ultrasound measurements of external anal sphincter muscle diameter and perineal length, which were compared to measurements obtained by digital examination. Results: Pearson's correlation coefficients for comparing the digital external sphincter examination to trans‐perineal ultrasonography, and the digital perineal examination to trans‐perineal ultrasonography were 0.88 and 0.40, respectively. Patients (n=4/34) whose external sphincter was identified as less than 1 cm by digital examination were found to have an external sphincter diameter of less than 1 cm by trans‐perineal ultrasound. Conclusion: The digital perineum examination is a reliable method of measuring the external sphincter thickness and perineal body length immediately after primary repair.
Direction‐dependent resistance to flow in the endplate of the intervertebral disc: an ex vivo study
Authors: Ayotte D. C. , Ito K. , Tepic S. 
Published: October 2002

AbstractA comparison of the higher hydrostatic pressure in the nucleus of the healthy intervertebral disc during daily loading with the relatively lower osmotic swelling pressure in the disc during rest suggests the existence of direction‐dependent flow resistance such that all of the fluid exuded from the disc during loading is recovered during rest. In this study, this direction‐dependent resistance was demonstrated for flows through the cartilage endplates and the underlying marrow contact channels in the bony endplates. Using an ex vivo sheep endplate model, the resistance ratio (Rout/Rin) for flow through the endplate was 39.0 ± 3.8 (mean ± S.E.). In addition, a path of fluid flow through the marrow contact holes was revealed using fluorescent staining. © 2001 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.
Involvement of BMP‐2 signaling in a cartilage cap in osteochondroma
Authors: Nakase Takanobu , Myoui Akira , Shimada Kozo , Kuriyama Kohji , Joyama Susumu , Miyaji Takahiro , Tomita Tetsuya , Yoshikawa Hideki 
Published: October 2002

AbstractThis study describes the distributions of bone morphogenetic protein (BMP)‐2 as well as mRNAs for BMP receptor type IB (BMPRIB), collagen types II (Col II) and III (Col III) in a growing “cartilage cap” of osteochondroma. In situ hybridization and immunohistochemical study were performed using histological sections obtained during surgery. BMP‐2 was detected in mesenchymal cells in the outer fibrous layer and chondrocytes in the inner cartilaginous matrix, positive for Col III and Col II, respectively. BMPRIB mRNA was distributed in chondrocytes. This is the first study to provide observational evidence of the involvement of BMP‐2 signaling in the pathogenesis of cartilage cap of osteochondroma, and suggests the role of BMP‐2 in the growth of cartilage cap in osteochondroma. © 2001 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.
Characterization of nucleus pulposus‐like tissue formed in vitro
Authors: Sun Yongliang , Hurtig Mark , Pilliar Robert M. , Grynpas Marc , Kandel Rita A. 
Published: October 2002

AbstractIn order to be able to study the metabolism of nucleus pulposus (NP) tissue, we developed a cell culture system that resulted in the formation of NP‐like tissue in vitro. NP cells were isolated from sheep lumbar spines and grown on filter inserts (Millicell CM®). Histological examination showed that the cells accumulated extracellular matrix and formed a continuous layer of NP‐like tissue. The accumulation of sulfated proteoglycans in the NP‐like tissue continued up to 10 weeks and this was paralleled by an increase in tissue thickness and dry weight. DNA content remained stable during the first 4 weeks but then decreased over time. The amount of DNA, glycosaminoglycan (GAG) and collagen per mg dry weight of the tissue generated after 10 weeks in culture were 1.25 ± 0.02, 301.6 ± 27.7 and 411 ± 65 μg, respectively, compared with 1.04 ± 0.08, 320.6 ± 21.2 and 399 ± 4.4 μg (mean ± SEM) for the in vivo tissue. There was no significant difference between in vitro and in vivo tissue. The cells in culture synthesized large proteoglycans (kav = 0.26 ± 0.03, mean ± S.D.) which were similar in size to those synthesized by cells in NP tissue in ex vivo culture (kav = 0.22 ± 0.02, mean ± S.D.) as determined by Sepharose CL‐2B column chromatography. The in vitro generated tissue contained type II collagen as demonstrated by sodium dodecyl sulfate‐polyacrylamide gel (SDS‐PAGE) and silver staining as well as Western blot analysis. NP cells grown on filters generate tissue similar in composition to the in vivo tissue, for the characteristics examined to date, and should be a suitable model to use to study NP metabolism and extracellular matrix turnover. © 2001 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.
The role of osteoclast differentiation in aseptic loosening
Authors: Greenfields Edward M. , Bi Yamming , Ragab Ashraf A. , Goldberg Victor M. , Van De Motter R. Renee 
Published: October 2002

AbstractThe major cause of orthopaedic implant loosening is thought to be accelerated osteoclastic bone resorption due to the action of cytokines produced in response to phagocytosis of implant‐derived wear particles. This accelerated osteoclastic bone resorption could be due to increases in any of the following processes: recruitment of osteoclast precursors to the local microenvironment, differentiation of precursors into mature multinucleated osteoclasts, activation of mature osteoclasts, and/or survival of osteoclasts. Our studies have focused on differentiation and survival to complement work by others who have focused on recruitment of precursors and activation. Taken together, our studies and those of other investigators provide strong evidence that increased recruitment of osteoclast precursors and their subsequent differentiation play major roles in wear particle‐induced osteolysis. In contrast, increased osteoclast activation and survival appear to play minor roles. These studies suggest that development of therapeutic interventions that reduce either recruitment or differentiation of osteoclast precursors would improve the performance of orthopaedic implants. © 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.
A biodegradable composite scaffold for cell transplantation
Authors: Ameer G. A. , Mahmood T. A. , Langer R. 
Published: October 2002

AbstractCell transplantation is rapidly becoming a therapeutic option to treat disease and injury. However, standard techniques for cell seeding on non‐woven polymer meshes or within gels may not be suitable for immediate implantation or surgical manipulations of freshly isolated cells. Therefore, a biodegradable composite system was developed as a way to rapidly entrap cells within a support of predefined shape to potentially facilitate cell delivery into a target site (e.g. meniscal tears in the avascular zone). The composite construct consisted of freshly isolated cells, in this case pig chondrocytes, entrapped in a fibrin gel phase and dispersed throughout the void volume of a polyglycolic acid (PGA) non‐woven mesh. Composites were cultured for up to 4 weeks. In vitro degradation of fibrin gel was evaluated via gel‐entrapped urokinase. At 28 days in culture, glycosaminoglycan (GAG) content per cell in the composite scaffolds was 2.6 times that of the PGA‐only cell construct group and 88% that of native pig cartilage. Total collagen content per cell in the composite scaffolds was not significantly different from the PGA‐only cell construct group (P > 0.02) and represented 40% of the value determined for native cartilage. Varying the concentration of entrapped urokinase could effect controlled degradation of fibrin gel. © 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.
Nitric oxide induces osteoblast apoptosis through the de novo synthesis of Bax protein
Authors: Chen Ruei‐Ming , Liu Hwa‐Chang , Lin Yi‐Ling , Jean Wen‐Chyi , Chen Jui‐Shui , Wang Jyh‐Horng 
Published: October 2002

AbstractNitric oxide (NO) plays a crucial role in the physiological and pathophysiological regulations of osteoblast functions. This study is designed to evaluate the toxic effects of NO released by sodium nitroprusside (SNP), an NO donor, on neonatal Wistar rat calvarial osteoblasts from the analyses of cell viability, alkaline phosphatase (ALP) activity, cell morphology, apoptotic cells, terminal deoxynucleotidyl transferase‐mediated dUTP nick end‐label (TUNEL) assay, DNA ladder, and immunocytochemistry and Western blot for proapoptotic Bax protein. SNP increased the levels of nitrite, an oxidative product of NO, in the culture medium of osteoblasts in concentration‐ and time‐dependent manners, and altered cell morphologies to round and shrinkage shapes. Administration of osteoblasts with SNP resulted in concentration‐ and time‐dependent decreases of cell viability and ALP activity. Analysis of apoptotic cells revealed that SNP increased the percentages of osteoblasts processing apoptosis. Analyses of TUNEL and DNA ladder showed that SNP caused DNA fragmentation. Pretreatment with cycloheximide, an inhibitor of protein synthesis, partially blocked SNP‐induced osteoblast apoptosis. Imunocytochemical and immunoblotting analyses revealed that SNP increased Bax protein in osteoblasts. This study suggests that SNP could increase the levels of NO in osteoblasts, and cause osteoblast apoptosis possibly through the de novo synthesis of proapoptotic Bax protein. © 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.
Plantar impact causing midfoot fractures result in higher forces in Chopart's joint than in the ankle joint
Authors: Richter M. , Wippermann B. , Thermann H. , Schroeder G. , Otte D. , Troeger H. D. , Krettek C. 
Published: October 2002

AbstractPurpose. Force effect (impact, extent of foot compartment deformation) and result (fracture pattern) for midfoot fractures in car occupants is known. An analysis of the processes in the foot was intended to improve car safety.Materials and methods. Eleven fresh, unfrozen, unpreserved intact human cadavers (age: 36.8 (16–61) years, gender: male, race: Caucasian) were studied 24–72 h after death. In 3 cadavers (5 feet) the experimental design was established: entire cadaver fixed on a special tray in supine position, pendulum with bar impactor hitting the foot plantar to Lisfranc's joint. A custom‐made pressure sensor was inserted in the ankle (A), talonavicular (TN) and calcaneocuboid (CC) joints (resolution: 1 cm2, sampling rate: 500/s).Results. Sixteen feet were measured; midfoot fractures were induced in 11 feet. The maximum pressure amounted to 1.22–2.55 MPa (2.04 ± 0.412) at 0.005–0.195 s (0.067 ± 0.059) after impact. The maximum pressure occurred in 8 (50%) cases in the ankle, in 7 (44%) of the TN and 1 (6%) of the CC joints. A comparison of the first 200 pressure samples after impact of all sensor fields resulted in higher forces in Chopart's joint than in the ankle (t‐test: p < 0.001). These force differences were higher in cases with midfoot fractures (mixed model analysis of variance: p = 0.003).Conclusion. Due to considerable forces in Chopart's joint we recommend a modification of the actual crash test dummy lower extremity model with an additional load cell that detects forces in the longitudinal direction of the foot axis. © 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.
The characterization of versican and its message in human articular cartilage and intervertebral disc
Authors: Sztrolovics Robert , Grover Judy , Cs‐Szabo Gabriella , Shi Shui‐Liang , Zhang Yiping , Mort John S. , Roughley Peter J. 
Published: October 2002

AbstractSplicing variation of the versican message and size heterogeneity of the versican core protein were analyzed in human articular cartilage and intervertebral disc. Splicing variation of the message was studied by PCR analysis to detect the presence or absence of exons 7 and 8, which encode large chondroitin sulfate attachment regions. At all ages in normal cartilage from the third trimester fetus to the mature adult, the presence of the versican isoform possessing exon 8 but not exon 7 (V1) could be readily detected. The message isoforms possessing neither exon 7 nor 8 (V3) or both exons 7 and 8 (V0) were only detectable in the fetus, and the isoform possessing only exon 7 (V2) was never detected. In osteoarthritic cartilage and in adult intervertebral disc the versican message pattern was the same as that observed in the normal adult with only the isoform possessing exon 8 being detected. Core protein heterogeneity was studied by immunoblotting following enzymic removal of the glycosaminoglycan chains from the proteoglycan, using an antibody recognizing the globular G1 region of versican. All articular cartilage extracts from the fetus to the mature adult contained multiple core protein sizes of greater than 200 kDa. The adult cartilage extracts tended to have an increased proportion of the smaller sized core proteins and osteoarthritic cartilage possessed similar core protein sizes to the normal adult. In contrast, intervertebral disc at all post‐natal ages showed a greater range of size heterogeneity with a prominent component of about 50 kDa. The abundance of this component increased if the samples were treated with keratanase prior to analysis, suggesting that the G1 region of versican in disc can be substituted with keratan sulfate. The increased presence of versican in the disc relative to articular cartilage may suggest a more pronounced functional role for this proteoglycan, particularly in the nucleus pulposus. © 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.
Photodynamic treatment has chondroprotective effects on articular cartilage
Authors: Sullivan Lawrence G. , Hasan Tayyaba , Wright Marianne , Mankin Henry J. , Towle Christine A. 
Published: October 2002

AbstractOsteoarthritis (OA) is a disabling joint disease for which there is currently no cure. It is characterized by the destruction of articular cartilage. One strategy that is being explored for protecting the cartilage in OA is the administration of transforming growth factor‐β, which in vitro antagonizes cartilage degradation initiated by catabolic stimulants such as interleukin‐1 (IL‐1). The problems associated with selective delivery of the growth factor to chondrocytes, undesirable side‐effects on joint tissues, and short biological half‐life have led us to explore modalities aimed at activating transforming growth factor‐β that is stored in the cartilage as latent complexes. Photodynamic therapy is a two‐step protocol of tissue sensitization with a light‐activatable chemical called a photosensitizer followed at some interval by irradiation with the appropriate wavelength visible light. Biological effects are typically elicited through oxygen‐dependent photochemistry without heat generation. Transforming growth factor‐β1 can be activated by oxidative mechanism(s), prompting us to explore whether photodynamic technology can be harnessed to modulate cartilage metabolism. Disks of bovine articular cartilage were photosensitized by incubation with a chlorine6‐succinylated polylysine conjugate and irradiated with 1–2 J/cm2 red light (λmax = 671 nm). This two‐step regimen dramatically inhibited IL‐1‐stimulated proteoglycan degradation and concomitantly increased latent and active transforming growth factor‐β1 in culture medium. This research may lead to the development of minimally invasive photodynamic therapy in which light is delivered to locally activate a chondroprotective program in photosensitized cartilage in the context of OA. © 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.
Development of a cellular model to study alternative splicing of type II collagen gene
Authors: Hatano H. , Sarkar G. , Bolander M. E. 
Published: October 2002

AbstractTo study regulation of alternative splicing of type II collagen (COL2) pre‐mRNA, we constructed a mouse COL2 “minigene” containing genomic sequences spanning exon 1 to exon 4 of COL2 downstream of a cytomegalovirus (CMV) promoter. This minigene was introduced into ATDC5 cells, which undergo chondrocytic differentiation when treated with insulin. Alternative splicing of the COL2 minigene was evaluated by comparing the expression of the two mRNAs transcribed from the minigene to the expression of alternatively spliced transcripts from the endogenous COL2 gene: This analysis suggested that regulation of alternative splicing of pre‐mRNAs from the minigene and the endogenous COL2 gene are accomplished by similar mechanisms. We conclude that the cloned genomic fragment contains key sequences necessary for alternative splicing of COL2 pre‐mRNA. This system provides a useful model to begin the process of identifying cis‐ and trans‐acting factors that carry out alternative splicing of COL2 pre‐mRNA during chondrocyte differentiation. © 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.
The insertion site of the canine flexor digitorum profundus tendon heals slowly following injury and suture repair
Authors: Silva Matthew J. , Boyer Martin I. , Ditsios Konstantinos , Burns Meghan E. , Harwood Frederick L. , Amiel David , Gelberman Richard H. 
Published: October 2002

AbstractTreatment of injuries of the flexor digitorum profundus (FDP) tendon insertion site has changed little during the past 50 years, in part because there are no reports describing flexor tendon insertion site healing. Our objective was to assess the effects of repair technique and post‐operative time on tendon–bone healing using a canine model of injury and repair. We transected 48 FDP tendons from 24 dogs at their insertions and repaired them using either a four‐ or eight‐strand suture technique. We assessed the mechanical properties of the repaired tendon–bone construct, tendon collagen biochemistry, and distal phalanx bone mineral density (BMD) at 0, 10, 21 and 42 days. Suture method had no significant effect on any outcome (p > 0.05). In particular, use of an eight‐strand double modified Kessler technique did not result in increased stiffness or strength compared to a four‐strand technique. With time, the repair site became stiffer, as demonstrated by a 230% increase in rigidity and a 50% decrease in strain from 0 to 42 days. However, from 0 to 42 days the ultimate force of the insertion site did not increase. This lack of increase in ultimate force was consistent with decreases in collagen content, non‐reducible crosslinks and distal phalanx BMD. Taken together, our results indicate that the canine FDP tendon heals slowly after it is injured at its insertion site and sutured onto the distal phalanx. While these findings may be limited to the particular repair method we used, they demonstrate a need for devising new treatment strategies to improve healing of flexor tendon insertion site injuries. © 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.
Evaluation of an external device measuring knee joint rotation: an in vivo study with simultaneous Roentgen stereometric analysis
Authors: Almquist Per O. , Arnbjörnsson Arnbjörn , Zätterström Rose , Ryd Leif , Ekdahl Charlotte , Fridén Thomas 
Published: October 2002

AbstractAn external device (“rottometer”) specially designed to measure knee joint rotation was developed and evaluated with respect to its validity. Simultaneous measurements were made with the rottometer and Roentgen stereometric analysis (RSA) in five patients with implanted tantalum markers in the tibia and femur. Measurements of internal and external rotation were made at 90° and 60° of knee flexion using 3, 6 and 9 N m torques. The coefficients of determination (r2) between the results obtained with the rottometer and RSA were around 0.9 for the total rotation. The rottometer consistently overestimated the rotation by about 100% and this systematic error was most constant at 90° flexion for the different torques. The magnitude of this error from soft tissue deformation as well as the rotatory movements in the hip, foot and ankle joints must be considered when using external devices to measure knee rotation in clinical studies. The most accurate registrations were found in 90° flexion with 9 N m force (r2 = 0.94). © 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.
In vivo fatigue loading of the rat ulna induces both bone formation and resorption and leads to time‐related changes in bone mechanical properties and density
Authors: Hsieh Yeou‐Fang , Silva Matthew J. 
Published: October 2002

AbstractFatigue loading triggers bone resorption and is associated with stress fractures. Neither the osteogenic response nor the changes in bone mechanical properties following in vivo fatigue loading have been quantified. To further characterize the skeletal response to fatigue loading, we assessed bone formation, mechanical properties, density and resorption in the ulnae of 72 adult rats subjected to a single bout of in vivo loading followed by 0, 6, 12 or 18 days of recovery. Axial, compressive loading (peak force 13.3 N, 2 Hz) was applied to the right forelimb until the ulna was fatigued to a pre‐determined level. The left forelimb served as a contralateral control. The primary osteogenic response to fatigue loading was woven bone formation that occurred on the periosteal surface of the ulnar diaphysis and was significantly greater in loaded limbs versus controls at 6, 12 and 18 days (p < 0.05). Ultimate force of the ulna in three‐point bending decreased by 50% and stiffness decreased by 70% on day 0 (p < 0.01 vs. control), indicative of acute fatigue damage. By day 12, ultimate force and stiffness had returned to control levels (p > 0.05) and by day 18 had increased 20% beyond controls (p < 0.01). Bone cross‐sectional area, moment of inertia, and mineral content increased with recovery time (p < 0.01), consistent with the increases in woven bone formation and mechanical properties. Intracortical resorption space density and osteoclast density also increased with recovery time (p < 0.05), indicating activation of intracortical remodeling. In summary, our findings demonstrate the remarkable ability of the adult skeleton to rapidly form periosteal woven bone and thereby offset the negative structural effects of acute fatigue damage and subsequent intracortical resorption. © 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.