bluuebunny/crossref_metadata_2025_split huggingface dataset:
A rat model for evaluating physiological responses to femoral shaft fracture reduction using a surgical robot
Authors: Oszwald Markus , Zhiyong Ruan  , Westphal Ralf , O'Loughlin Padhraig F. , Kendoff Daniel , Hufner Tobias , Wahl Friedrich , Krettek Christian , Gosling Thomas 
Published: July 2008

AbstractThe first step in treatment of displaced femoral shaft fractures is adequate reduction of the fracture fragments. Manually performed, reduction can be challenging, and is frequently associated with soft tissue damage, especially when repeated reduction attempts are made. The magnitude of local and systemic inflammatory responses caused by prolonged and repeated reduction maneuvers has not been fully established. We devised an operative technique utilizing a robotic reduction device for use in a rat. A femoral fracture was simulated by means of an osteotomy. The robot enabled reproduction of both manual and guided precision reductions, performed in a single path movement. An external fixator was designed specifically to manipulate the rat femur and also for fixation of the osteotomy region. First, reduction accuracy was assessed in eight femurs, then the quality of fixator placement and reduction accuracy was analyzed in 22 femurs. In the first case, 100% of the femurs were accurately reduced. In the second case, 91% had successful stable fixation and an accurate reduction was achieved in 86% of the specimens. We demonstrated the feasibility of a model of robot‐assisted fracture reduction that could be used to analyze the effects of reduction on the surrounding soft tissue via biochemical and histopathological means. A future aspect will be to evaluate whether the robot confers an advantage in fracture reduction versus the conventional technique, which would have significant implications for the use of robotic devices in orthopaedic surgery. © 2008 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res
Gender‐dependent association of the GNAS1 T393C polymorphism with early aseptic loosening after total hip arthroplasty
Authors: Bachmann Hagen S. , Hanenkamp Sandra , Kornacki Bartlomiej , Frey Ulrich H. , Bau Maja , Siffert Winfried , Wedemeyer Christian 
Published: July 2008

AbstractThe G‐protein Gαs is involved in the physiology and pathophysiology of bone. Especially, Gαs is a key regulator of interleukin‐6, which is a potent promoter of aseptic loosening. We hypothesized that the common single nucleotide polymorphism GNAS1 T393C could also affect time to aseptic loosening. Caucasian patients were genotyped for the GNAS1 T393C polymorphism. Time and median time to aseptic loosening were analyzed for dependency on GNAS1 genotypes. Time and median time were not significantly associated with genotypes. Additional analysis corrected for gender revealed, that the TT genotype was associated with significantly longer time (p = 0.048) as well as median time (p = 0.022) to aseptic loosening in female patients. In contrast to the findings in females, male TT genotype carriers had significantly shorter time (p = 0.018) and median time (p = 0.023) to aseptic loosening. Compared with TT genotype carriers heterozygous patients had a 6.25‐fold lower risk with a hazard ratio of 0.160 (p = 0.016) and male patients carrying the CC genotype had an 11‐fold lower risk with a hazard ratio of 0.088 (p = 0.006) in multivariate analysis. The present study suggests a significant gender‐dependent role of the T393C polymorphism in aseptic loosening. The apparently contradictory results in women and men and the finding that the GNAS1 T393C genotype is an independent factor for time to aseptic loosening in male patients assigned this polymorphism as an interesting target for further investigations in bone diseases. © 2008 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res
Plantar pressure distribution in older people with osteoarthritis of the first metatarsophalangeal joint (hallux limitus/rigidus)
Authors: Zammit Gerard V. , Menz Hylton B. , Munteanu Shannon E. , Landorf Karl B. 
Published: July 2008

AbstractThe purpose of this study was to evaluate differences in dynamic plantar pressure distribution between older people with and without radiographically confirmed osteoarthritis (OA) of the first metatarsophalangeal joint (first MPJ) of the foot. Dynamic plantar pressure recordings using the TekScan MatScan® system were obtained during barefoot level walking in 40 older participants; 20 with radiographically confirmed OA of the first MPJ displaying less than 55 degrees of passive dorsiflexion, and 20 with no evidence of OA in the first MPJ displaying greater than 55 degrees of passive dorsiflexion. Group comparisons between the variables maximum force and peak pressure were made for seven different regions underneath the right foot (heel, midfoot, first MPJ, second MPJ, third to fifth MPJs, hallux, and lesser toes). Compared to the control group, participants with OA of the first MPJ exhibited 34% greater maximum force (7.9 ± 2.5 vs. 5.9 ± 1.7 kg, p = 0.005) and 23% higher peak pressure (1.6 ± 0.3 vs. 1.3 ± 0.3 kg/cm2, p = 0.001) under the hallux. Similar results were also found under the lesser toes with 43% greater maximum force (5.0 ± 1.9 vs. 3.5 ± 1.4 kg; p = 0.006) and 29% higher peak pressure (0.9 ± 0.2 vs. 0.7 ± 0.2 kg/cm2, p = 0.018). No significant differences were found to exist between groups for any other plantar region. These findings indicate that OA of the first MPJ is associated with significant changes in load‐bearing function of the foot, which may contribute to the development of secondary pathological changes associated with the condition, such as plantar callus formation and hyperextension of the hallux interphalangeal joint. © 2008 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res
The association between velocity of the center of closest proximity on subchondral bones and osteoarthritis progression
Authors: Anderst William J. , Tashman Scott 
Published: July 2008

AbstractAltered surface interactions following joint instability may apply novel, damaging loads to articular cartilage. This study measured the velocity of the centers of closest proximity on subchondral bone surfaces on the femur and tibia during running in normal and unstable canine stifle (knee) joints. The purpose was to explore the relationship between the velocity of the centers of closest proximity on subchondral bones and the severity of cartilage damage. Dynamic biplane radiography was used to acquire serial knee kinematics [5 control, 18 cranial cruciate ligament (CCL) deficient] during treadmill running over 2 years. Custom software calculated the difference between the rate at which the center of closest proximity on the femur translated relative to the femur bone surface and the rate at which the center of closest proximity on the tibia translated relative to the tibia bone surface. Comparisons were made between dogs that developed minor versus major medial compartment cartilage damage over 2 years. Major damage dogs showed a significantly greater increase in the difference between femur and tibia medial compartment closest proximity point velocity from the instant of paw strike to peak velocity difference at 2, 4, and 6 months after CCL transaction. This implies increased tangential forces associated with the velocity of the compressed cartilage region during joint movement (plowing) may be a mechanism that initiates osteoarthritis (OA) development and drives OA progression. In the future, articulating surface velocity measurements may be useful to identify patients at risk for long‐term OA due to joint instability. © 2008 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 27:71–77, 2009
Hypoxia upregulates the expression of angiopoietin‐like‐4 in human articular chondrocytes: Role of angiopoietin‐like‐4 in the expression of matrix metalloproteinases and cartilage degradation
Authors: Murata Minako , Yudo Kazuo , Nakamura Hiroshi , Chiba Junji , Okamoto Kazuki , Suematsu Naoya , Nishioka Kusuki , Beppu Moroe , Inoue Kazuhiko , Kato Tomohiro , Masuko Kayo 
Published: July 2008

AbstractThe objective of this article was to investigate the role and expression of a novel adipocytokine, angiopoietin‐like‐4 (ANGPTL4), in arthropathy. Human chondrocytes were obtained from articular cartilage of patients with rheumatoid arthritis (RA) and osteoarthritis (OA), who underwent total knee or hip arthroplasty. Isolated chondrocytes were cultured under hypoxic (95% N2, 5% CO2) or normoxic conditions. The effects of hypoxia on ANGPTL4 expression were determined by real‐time reverse transcription polymerase chain reaction and Western blot analysis. We examined the role of ANGPTL4 using small interference RNA or by stimulating chondrocytes with recombinant ANGPTL4 protein. ANGPTL4 expression in the articular cartilage specimens was examined by immunohistochemistry. Hypoxia induced a significant increase in ANGPTL4 production (p < 0.05). Incubation of chondrocytes in vitro with recombinant ANGPTL4 enhanced the expression of matrix metalloproteinase (MMP)‐1 and MMP‐3. Downregulation of ANGPTL4 mRNA expression by siRNA diminished the expression of MMP‐1, but not that of MMP‐3, suggesting that each proteinase has a distinct response to ANGPTL4. Although the in vitro responses of chondrocytes to hypoxia were similar between RA and OA samples, the in vivo expression of ANGPTL4 had unique disease‐specific patterns, suggesting differences in oxygen tension in vivo. Human chondrocytes expressed ANGPTL4 and the expression was enhanced by hypoxia. ANGPTL4 might modulate cartilage metabolism by regulating MMPs. © 2008 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 27:50–57, 2009
Cartilage damage caused by metal implants applied for the treatment of established localized cartilage defects in a rabbit model
Authors: Custers Roel J.H. , Creemers Laura B. , van Rijen Mattie H.P. , Verbout Ab J. , Saris Daniel B.F. , Dhert Wouter J.A. 
Published: July 2008

AbstractThe purpose of the current study was to investigate the feasibility of the application of defect‐size femoral implants in a rabbit model of established cartilage defects and compare this treatment to microfracturing. In 31 New Zealand White rabbits, a medial femoral condyle defect was created in each knee. After 4 weeks, 3 animals were killed for defect baseline values. In the other 28 rabbits, knees were sham‐operated, treated with microfracturing, or treated by placing an oxidized zirconium (OxZr) or cobalt‐chromium (CoCr) implant (∅︁ articulating surface 3.5 mm; fixating pin of 9.1 mm length). These animals were sacrificed 4 weeks after treatment. Joints were evaluated macroscopically. Implant osseointegration was measured by automated histomorphometry, and cartilage repair was scored microscopically. Cartilage quality was analyzed macroscopically and microscopically. Bone–implant contact was 63.2% ± 3.2% for CoCr and 62.5% ± 3.2% for OxZr. Cartilage defects did not show complete healing, nor during subsequent sham‐surgery or microfracturing. For all treatments, considerable cartilage damage in the articulating medial tibia, and degeneration of lateral tibial and femoral cartilage was observed (p < 0.05). Both CoCr and OxZr implant‐treated defects showed an increase of cartilage degeneration compared to microfracturing and sham‐operated defects (p < 0.05). Although only a single short‐term follow‐up period was investigated in this study, caution is warranted using small metal implants as a treatment for established localized cartilage defects because, even after 4 weeks in this model, the metal implants caused considerable degeneration of the articulating surface. © 2008 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 27:84–90, 2009
Quantitative motion analysis in patients with hallux rigidus before and after cheilectomy
Authors: Canseco Karl , Long Jason , Marks Richard , Khazzam Michael , Harris Gerald 
Published: July 2008

AbstractThe purpose of this study was to quantify changes in temporal‐spatial parameters and multisegmental foot/ankle kinematics in a group of patients with hallux rigidus following cheilectomy. Three‐dimensional motion analysis was conducted using a 15‐camera Vicon Motion Analysis System on a population of 19 patients who underwent cheilectomy for hallux rigidus. Data were analyzed using the four‐segment Milwaukee Foot Model. Preoperative and postoperative tests were compared using paired parametric methods. Results showed significant improvements in walking speed, cadence, stride length, and stance/swing ratio from preoperative to postoperative state. Altered hallux and forefoot positions preoperatively showed shifts towards normal after cheilectomy. Although clinical improvements in pain and passive range of motion were statistically significant, similar improvements in range of motion were not demonstrated during ambulatory testing. The results of this study provide insight into ambulatory improvements following cheilectomy, and suggest further study of the rehabilitation process to improve the recovery of functional range of motion. © 2008 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 27:128–134, 2009
Early dynamization by reduced fixation stiffness does not improve fracture healing in a rat femoral osteotomy model
Authors: Claes Lutz , Blakytny Robert , Göckelmann Melanie , Schoen Marcus , Ignatius Anita , Willie Bettina 
Published: July 2008

AbstractDynamization of fracture fixation is used clinically to improve the bone healing process. However, the effect of early dynamization remains controversial. This study evaluated the effect of early dynamization, by reduced stiffness of fixation on callus stiffness and size after 5 weeks of healing in a rat diaphyseal femoral osteotomy. An external unilateral fixator allowed either a rigid (R‐group; n = 8) or a flexible (F‐group; n = 8) fixation. The dynamized group (D‐group: n = 8) had a rigid fixation for 1 week, and then a flexible fixation for the remaining 4 weeks. The pre‐ and postoperative activity of the rats was measured. After 5 weeks, the rats were sacrificed, and healing was evaluated by biomechanical and densitometric methods. The R‐group had a higher activity more closely approaching preoperative levels, compared to the D‐group throughout all time points measured. This difference was significant after 14 days and 21 days. The flexural rigidity of the R‐group was 82% (tested in the anterior‐posterior direction; p = 0.01) and 93% (tested in the medial‐lateral direction; p = 0.002) greater than the flexural rigidity of the D‐group. The rigid fixation led to a stiffer callus with a smaller callus volume, but better mineralized tissue in the whole callus and at the level of the osteotomy gap than the flexible or the dynamized fixation. Early dynamization did not improve healing compared to rigid or flexible fixation in a rat femoral osteotomy model. © 2008 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 27:22–27, 2009
The small GTPase Rho mediates articular chondrocyte phenotype and morphology in response to interleukin‐1α and insulin‐like growth factor‐I
Authors: Novakofski Kira , Boehm Amber , Fortier Lisa 
Published: July 2008

AbstractSmall GTPases regulate the cytoskeleton and numerous other cellular functions. In this study, the role of Rho GTPase was examined in articular chondrocytes. Chondrocytes grown in monolayer were treated with interleukin‐1α (IL‐1α), insulin‐like growth factor‐I (IGF‐I), C3 Transferase, Y27632, or transfected with Rho wild type or two constitutively active mutants of Rho (Q63L and G14V). Quantitative PCR was used to determine changes in matrix metalloproteinase‐13 (MMP‐13), collagen types IIB (COL2A1) and type I (COL1A1), aggrecan (AGG), and SOX‐9 gene expression. Affinity assays were performed to measure endogenous GTP‐bound Rho, and confocal microscopy was used to assess changes in organization of the actin cytoskeleton. IL‐1α and RhoG14V increased cytoplasmic actin stress fiber formation, which was blocked by C3 Transferase, and Y27632. IL‐1α treatment also increased Rho activity. Conversely, IGF‐I lead to formation of a cortical rim of actin and decreased Rho activity. Inhibition of Rho signaling with C3 Transferase significantly decreased Rho activity and returned IL‐1α‐induced Rho activity to a level not different from control. C3 Transferase treatment also increased mRNA expression of AGG, COL2A1, and SOX‐9, and decreased expression of MMP‐13. Expression of RhoQ63L or RhoG14V resulted in increased MMP‐13 expression; however, inhibition of Rho with Y27632 was unable to inhibit IL‐1α‐induced MMP‐13 expression. Together, these results indicate a role for increased Rho activity in mediation of chondrocyte catabolic signaling pathways. © 2008 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 27:58–64, 2009
Proximal gait adaptations in medial knee OA
Authors: Briem Kristin , Snyder‐Mackler Lynn 
Published: July 2008

AbstractThe purpose of this study was to examine interlimb differences in gait kinematics and kinetics in patients with symptomatic medial knee OA. The main objective was to identify hip joint movement strategies that might lower the knee adduction moment and also compensate for decreased knee flexion during weight acceptance. Gait analysis was performed on 32 patients with moderate medial compartment knee OA. Kinetic and kinematic data were calculated and side‐to‐side comparisons made. Radiographs were used to identify frontal plane alignment. No interlimb difference in the peak knee adduction moment was found (p = 0.512), whereas a greatly reduced hip adduction moment was seen on the involved side (p < 0.001) during the early part of stance. The involved limb flexed significantly less and hip and knee flexion moments were smaller compared to the uninvolved side. Gait adaptations involving a lateral sway of the trunk may successfully lead to relatively lower ipsilateral knee adduction moments, and would further be reflected by a lower adduction moment at the hip. Subjects did not compensate for less knee flexion by any dynamic means, and likely experience a resulting higher joint impact. These gait adaptations may have implications with respect to development of weakness of the ipsilateral hip musculature and progression of multiarticular OA. © 2008 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 27:78–83, 2009
In vivo effects of modification of hydroxyapatite/collagen composites with and without chondroitin sulphate on bone remodeling in the sheep tibia
Authors: Schneiders Wolfgang , Reinstorf Antje , Biewener Achim , Serra Alexandrè , Grass Renè , Kinscher Michael , Heineck Jan , Rehberg Sebastian , Zwipp Hans , Rammelt Stefan 
Published: July 2008

AbstractThe addition of chondroitin sulphate (CS) to bone cements with calcium phosphate has lead to an enhancement of bone remodeling and an increase in new bone formation in small animals. The goal of this study was to verify the effect of CS in bone cements in a large animal model simulating a clinically relevant situation of a segmental cortical defect of a critical size on bone–implant interaction and bone remodeling. The influence of adding CS to hydroxyapatite/collagen (HA/Col) composites on host response was assessed in a standard sheep tibia model. A midshaft defect of 3 cm was created in the tibiae of 14 adult female sheep. The defect was filled with a HA/Col cement cylinder in seven animals and with a CS‐modified hydroxyapatite/collagen (HA/Col/CS) cement cylinder in seven animals. In all cases the tibia was stabilized with an interlocked universal tibial nail. The animals in each group were analyzed with X‐rays, CT scans, histology, immunohistochemistry, and enzymehistochemistry, as well as histomorphometric measurements. The X‐ray investigation showed a significantly earlier callus reaction around the HA/Col/CS implants compared to HA/Col alone. The amount of newly formed bone at the end point of the experiment was significantly larger around HA/Col/CS cylinders both in the CT scan and in the histomorphometric analysis. There were still TRAP‐positive osteoclasts around the HA/Col implants after 3 months. The number of osteopontin‐positive osteoblasts and the direct bone contact were significantly higher around HA/Col/CS implants. We conclude that addition of CS enhances bone remodeling and new bone formation around HA/Col composites. © 2008 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 27:15–21, 2009
Raman and DFT study of hydrogen‐bonded 2‐ and 3‐chloropyridine with methanol
Authors: Singh Deepa , Vikram K. , Singh Dheeraj K. , Kiefer W. , Singh Ranjan K. 
Published: July 2008

AbstractPrecise polarized Raman measurements of 2‐chloropyridine (2Clpy) in the region 560–1060 cm−1 and 3‐chloropyridine (3Clpy) in the region 680–1080 cm−1 at different concentrations in mole fraction of methanol were made to calculate the isotropic part of the Raman spectra, which has contributions only from vibrational dephasing. A detailed analysis of the Raman spectra was carried out to see the variation of peak position and linewidth. The dephasing is mode specific. The trigonal bending mode of 3Clpy has two components when it is mixed with methanol. The relative intensities of these two bands are used to calculate the equilibrium constants. The ring‐breathing mode of 3Clpy, on the other hand, remains single in the mixture. The appearance of a new band corresponding to the trigonal bending mode, as well as the nonappearance of that of the ring‐breathing mode, is also shown by the density functional theory (DFT) study of gas phase and methanol‐solvated complexes. The vibrational dephasing time for the hydrogen‐bonded ring‐breathing mode is calculated from the linear Raman linewidth and peak position data. For other modes, it was not possible to calculate the dephasing time because of the nonavailability of a suitable theoretical model. Contrary to 3Clpy, in 2Clpy the ring‐breathing mode becomes a doublet but the trigonal bending mode remains single. It is seen that the hydrogen‐bonding capacity of chloropyridines is highly influenced by the position of the Cl atom. Single and double components of these modes are also explained by DFT calculations. We obtained excellent match of the experimental and theoretical spectra with the B3LYP/6‐31 + G (d,p) method. Copyright © 2008 John Wiley & Sons, Ltd.
Molecular vibrational imaging of a human cell by multiplex coherent anti‐Stokes Raman scattering microspectroscopy using a supercontinuum light source
Authors: Kano Hideaki 
Published: July 2008

AbstractMolecular vibrational images of human cells are obtained by multiplex coherent anti‐Stokes Raman scattering (CARS) microspectroscopy. The CARS images of HeLa cells at the CH stretching vibrational mode clearly show various organelles such as nucleolus, chromosome, cell membrane, and nuclear membrane with high vibrational contrast. Filament‐like structures are also found to be observed in interphase, while it is not clearly observed in M phase. These structures most probably visualize endoplasmic reticulum (ER) network. Copyright © 2008 John Wiley & Sons, Ltd.