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Meniscus
Kinds of Meniscus Selected AbstractsBottom,Up Fabrication of Carbon-Rich Silicon Carbide Nanowires by Manipulation of Nanometer-Sized Ethanol Menisci,ADVANCED MATERIALS, Issue 12 2005M. Tello A nanometer-sized ethyl alcohol meniscus induced between a conductive atomic force microscope tip and a silicon surface (see Figure) allows the fabrication of nanodots or nanowires of SiCx at a predetermined position on the substrate. The meniscus size and kinetic parameters control the nanostructure size. [source] Hyaluronan suppressed nitric oxide production in the meniscus and synovium of rabbit osteoarthritis modelJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 3 2001Kenji Takahashi Nitric oxide (NO) plays an important role in cartilage degeneration, and NO donors induce meniscus degeneration and synovium inflammation. This study evaluated the effect of intraarticular injections of hyaluronan (HA) on NO production in meniscus and synovium using an experimental osteoarthritis (OA) model. Thirty-six New Zealand white rabbits underwent unilateral anterior cruciate ligament transection (ACLT), and were divided into three groups. Four weeks after ACLT, the HA group started to receive intraarticular HA injections once a week for 5 weeks; the vehicle group started to receive the carrier of HA; and the no injection group, no treatment. All ACLT knees were harvested at the 9th week. Meniscus and synovium sections were examined by immunohistochemistry for nitrotyrosine. The pieces of these two tissues were cultured for 24 h. Culture supernatants were analyzed for nitrite concentration. The amount of NO produced by the meniscus was much larger than that produced by the synovium. NO productions in the meniscus and synovium of the HA group were significantly lower than those of the other groups. The results suggest that the inhibition of NO production in meniscus and synovium might be a part of the mechanism of the therapeutic effect of HA on OA. © 2001 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved. [source] Meniscus,Friend or foe: Epidemiologic observations and surgical implicationsARTHRITIS & RHEUMATISM, Issue 3 2009Jeffrey N. Katz No abstract is available for this article. [source] Analysis of the profile curves of the menisci for the sapphire tubes growth by EFG (Stepanov) techniqueCRYSTAL RESEARCH AND TECHNOLOGY, Issue 7 2009S. N. Rossolenko Abstract This paper deals with investigation of the behavior of the profile curves of the melt menisci for the case of the sapphire crystal growth by EFG (Stepanov) technique. The cases of external and internal circular menisci of the crystal tube are considered. The cases of the positive and negative angles of the contact of the profile curve with the working surface of the shaper are considered. Features of the profile curves are used in the automated control systems of the crystal growth using of the weight sensor. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] On the capillary stress tensor in wet granular materialsINTERNATIONAL JOURNAL FOR NUMERICAL AND ANALYTICAL METHODS IN GEOMECHANICS, Issue 10 2009L. Scholtès Abstract This paper presents a micromechanical study of unsaturated granular media in the pendular regime, based on numerical experiments using the discrete element method, compared with a microstructural elastoplastic model. Water effects are taken into account by adding capillary menisci at contacts and their consequences in terms of force and water volume are studied. Simulations of triaxial compression tests are used to investigate both macro and micro-effects of a partial saturation. The results provided by the two methods appear to be in good agreement, reproducing the major trends of a partially saturated granular assembly, such as the increase in the shear strength and the hardening with suction. Moreover, a capillary stress tensor is exhibited from capillary forces by using homogenization techniques. Both macroscopic and microscopic considerations emphasize an induced anisotropy of the capillary stress tensor in relation with the pore fluid distribution inside the material. Insofar as the tensorial nature of this fluid fabric implies shear effects on the solid phase associated with suction, a comparison has been made with the standard equivalent pore pressure assumption. It is shown that water effects induce microstructural phenomena that cannot be considered at the macro level, particularly when dealing with material history. Thus, the study points out that unsaturated soil stress definitions should include, besides the macroscopic stresses such as the total stress, the microscopic interparticle stresses such as the ones resulting from capillary forces, in order to interpret more precisely the implications of the pore fluid on the mechanical behaviour of granular materials. Copyright © 2009 John Wiley & Sons, Ltd. [source] Microstructural deformation mechanisms of unsaturated granular soilsINTERNATIONAL JOURNAL FOR NUMERICAL AND ANALYTICAL METHODS IN GEOMECHANICS, Issue 5 2002J. A. Gili Abstract A discrete model for unsaturated granular soils has been developed. Three discrete entities have been defined: particles, water menisci and pores. Local interaction forces and water transfer mechanisms have been integrated into a model through the appropriate equilibrium and balance equations. The results of several numerical tests using this model have been described and discussed. Simulations include wetting and drying under load tests, the application of suction cycles and the effect of a deviatoric stress ratio on wetting-induced collapse. The model reacts just as true granular soil samples behave in laboratory tests. The model provides a new insight into the internal mechanisms leading to large-scale features of behaviour such as wetting-induced collapse or the increase in soil strength provided by suction. The paper also stresses that matric suction changes acting on a granular structure are capable of explaining most of the macroscopic features of stress,strain behaviour. Copyright © 2002 John Wiley & Sons, Ltd. [source] Age-related changes in human meniscal glycosaminoglycansINTERNATIONAL JOURNAL OF EXPERIMENTAL PATHOLOGY, Issue 4 2004Gareth Blackburn Introduction With an increased human lifespan, a major challenge is now to ensure a concomitant increase in healthspan. Meniscal damage and degradation are common and are strongly correlated with subsequent osteoarthritis. Indeed, meniscal damage has been identified in about 60% of people over 60. Markers of pathology will facilitate intervention but first require normal age-related changes to be established. Methods Undamaged vascular and avascular regions of medial and lateral human menisci were comminuted and the tissue extracted into 4- m GuHCl and subject to associative CsCl density gradient centrifugation. Aggrecan and the small leucine rich PGs (SLRPs) were isolated and their GAG profiles examined by HPAEC fingerprinting, following enzyme depolymerization, and by an NMR spectroscopy. Results and discussion Analysis of aggrecan and the SLRPs show that there is a complex and dynamic pattern of KS, CS and DS abundance and distribution within human menisci, which changes with age. The abundance of SLRPs is higher in the avascular than vascular tissues, however, this is not reflected in the abundance of aggrecan which is present at similar levels in both tissue regions. The data show no other significant differences between medial and lateral and between vascular and avascular tissue regions. Analysis of the sulfation pattern of CS following digestion by ACII lyase, shows that in both aggrecan and SLRPs the 4-sulfation level falls with age from 20 to 35% in young tissues to 10,20% in older. Subsequent analyses following ABC lyase depolymerization, to include DS, shows very significant change with age from CS + DS 4-sulfation levels of ca. 40,55% in young tissue to ca. 15,30% in older. The difference between these datasets represents the contribution made by 4-sulfated DS. Thus, analysis of the difference suggests that DS makes a decreasing contribution to the CS/DS profile with age. Indeed, this is confirmed by an NMR analysis of these samples. Analysis of the resonances in the region 1.95,2.2 p.p.m. (ref to TSP) allows the estimation of the contribution made by DS, CS and KS. These data show that, in aggrecan, the contribution made by DS chains falls from ca. 10% in younger tissues to ca. 2,4% in older tissues. NMR analysis also shows that KS levels fall with age from ca. 15,20% in younger tissues to 5,10% in older tissues. Analysis of the structure of the KS chains shows chains with a structure similar to that of in articular cartilage but that at all ages there are very low levels of fucosylation (ca. 1,5%). Previous studies of age-related changes in CS/DS and KS structures have shown significant changes in the first 17 years of life, with only modest nonpathological changes after that time. These data from meniscal tissues do not show such a dramatic halting of normal age-related changes. Indeed, the data show gradual age-related changes in DS, CS and KS abundance and structure throughout life. These baseline age-related changes data will now allow the analysis of pathology-related changes. [source] Operating windows of slot die coating: Comparison of theoretical predictions with experimental observationsADVANCES IN POLYMER TECHNOLOGY, Issue 1 2010Chi-Feng Lin Abstract The objective of the present study is to examine the validity of the theoretical predictions on the operating windows of slot die coating. The operating window is defined as a domain inside which stable and uniform coating is possible; different types of coating defects are found outside the window. A flow visualization technique was applied to observe the coating bead, particularly the positions and shapes of the downstream and upstream menisci, just before and after coating defects appear at high coating speeds. Special features of coating bead shapes, which lead to onsets of ribbing and air entrainment, were identified. The two-dimensional flow in the coating bead region was computed by the commercial software package FLOW-3D®. Critical features observed experimentally for the onset of coating defects were used to judge whether the coating flow was within the operating window. The theoretically evaluated operating windows were found to be much larger than those determined experimentally in terms of coating speeds. However, the qualitative trends of theoretical predictions agree with experimental observations. © 2010 Wiley Periodicals, Inc. Adv Polym Techn 29:31,44, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/adv.20173 [source] Is there a role for sonography in the diagnosis of tears of the knee menisci?JOURNAL OF CLINICAL ULTRASOUND, Issue 8 2002Roberto Azzoni MD Abstract Purpose The aim of this study was to investigate the usefulness of sonography in diagnosing tears of the knee menisci. Methods In this retrospective study, we reviewed the sonographic examinations of the knees of 321 patients diagnosed with a torn meniscus on the basis of clinical findings. Of the 321 knees imaged, 216 were also examined using MRI or CT. Arthroscopic meniscectomy was performed on 126 knees. Results MRI or CT did not confirm 48% (71 cases) of the positive sonographic diagnoses (ie, false positives) and 72% (50 cases) of the negative sonographic diagnoses (ie, false negatives). Thus, the sonographic diagnosis was correct in 95 cases (44%) and incorrect in 121 cases (56%), yielding low rates of sensitivity (60%) and specificity (21%). Among the 126 cases in which arthroscopic meniscectomy was performed, arthroscopy confirmed 100% of the MRI or CT diagnoses of meniscal tears. Conclusions Our results indicate that sonography is not accurate enough to be used as the only imaging modality for diagnosing tears of the knee menisci. © 2002 Wiley Periodicals, Inc. J Clin Ultrasound 30:472,476, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI: 10.1002/jcu.10106 [source] Minute amounts of intraarticular gas mimicking torn discoid lateral menisciJOURNAL OF MAGNETIC RESONANCE IMAGING, Issue 3 2010Martin I. Jordanov MD Abstract Presented are two cases of minute amounts of vacuum phenomena within the central portion of the lateral compartments of two knee joints, mimicking torn discoid lateral menisci. In each case, only the gradient echo images were able to correctly characterize the minute quantities of intraarticular gas by demonstrating "blooming" magnetic susceptibility artifact. The signal characteristics of the intraarticular gas were identical to those of fibrocartilage on all of the remaining routine, fast spin echo, "sports protocol" magnetic resonance imaging sequences. J. Magn. Reson. Imaging 2010;31:698,702. © 2010 Wiley-Liss, Inc. [source] Detectable reporter gene expression following transduction of adenovirus and adeno-associated virus serotype 2 vectors within full-thickness osteoarthritic and unaffected canine cartilage in vitro and unaffected guinea pig cartilage in vivoJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 2 2010Kelly S. Santangelo Abstract This study quantified and compared the transduction efficiencies of adenoviral (Ad), Arg-Gly-Asp (RGD)-modified Ad, adeno-associated viral serotype 2 (AAV2), and self-complementary AAV2 (scAAV2) vectors within full-thickness osteoarthritic (OA) and unaffected canine cartilage explants in vitro. Intraarticular administration of Ad and scAAV2 vectors was performed to determine the ability of these vectors to transduce unaffected guinea pig cartilage in vivo. Following explant exposure to vector treatment or control, the onset and surface distribution of reporter gene expression was monitored daily with fluorescent microscopy. At termination, explants were divided: one half was digested for analysis using flow cytometry; the remaining portion was used for histology and immunohistochemistry (IHC). Intact articular joints were collected for real-time RT-PCR and IHC to detect reporter gene expression following injection of selected vectors. Ad vector transduced focal areas along the perimeters of explants; the remaining vectors transduced chondrocytes across 100% of the surface. Greater mean transduction efficiencies were found with both AAV2 vectors as compared to the Ad vector (p,,,0.026). Ad and Ad-RGD vectors transduced only superficial chondrocytes of OA and unaffected cartilage. Uniform reporter gene expression from AAV2 and scAAV2 was detected in the tangential and transitional zones of OA cartilage, but not deeper zones. AAV2 and scAAV2 vectors achieved partial and full-thickness transduction of unaffected cartilage. In vivo work revealed that scAAV2 vector, but not Ad vector, transduced deeper zones of cartilage and menisci. This study demonstrates that AAV2 and scAAV2 are reliable vectors for use in cartilage in vitro and in vivo. © 2009 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 28:149,155, 2010 [source] Kinematics of the knee at high flexion angles: An in vitro investigationJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 1 2004Guoan Li Abstract Restoration of knee function after total knee, meniscus, or cruciate ligament surgery requires an understanding of knee behavior throughout the entire range of knee motion. However, little data are available regarding knee kinematics and kinetics at flexion angles greater than 120° (high flexion). In this study, 13° cadaveric human knee specimens were tested using an in vitro robotic experimental setup. Tibial anteroposterior translation and internal,external rotation were measured along the passive path and under simulated muscle loading from full extension to 150° of flexion. Anterior tibial translation was observed in the unloaded passive path throughout, with a peak of 31.2 ± 13.2 mm at 150°. Internal tibial rotation increased with flexion to 150° on the passive path to a maximum of 11.1 ± 6.7°. The simulated muscle loads affected tibial translation and rotation between full extension and 120° of knee flexion. Interestingly, at high flexion, the application of muscle loads had little effect on tibial translation and rotation when compared to values at 120°. The kinematic behavior of the knee at 150° was markedly different from that measured at other flexion angles. Muscle loads appear to play a minimal role in influencing tibial translation and rotation at maximal flexion. The results imply that the knee is highly constrained at high flexion, which could be due in part to compression of the posterior soft tissues (posterior capsule, menisci, muscle, fat, and skin) between the tibia and the femur. © 2003 Orthopaedic Research Society. Published by Elsevier Ltd. All rights reserved. [source] The effect of tibial lengthening using the Ilizarov method on the cartilage and the menisci of the knee jointJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 4 2001Bernd Fink In order to investigate possible acute damage to the knee joint cartilage and the menisci during tibial lengthening, sixteen young beagle dogs underwent 30% lengthening of the right tibia of 2.5 cm by callus distraction at a distraction rate of twice 0.5 mm per day. A further four dogs comprised the control group with fixator and osteotomy but without lengthening. After a distraction period of 25 days half the dogs were killed (group A) while the other half (eight dogs with limb lengthening and two dogs without) were killed after a further period of 25 days (group B). At the end of the study, the menisci were removed together with three cartilage-bone cylinders from both femoral condyles from the weight-bearing zones as well as from the corresponding tibial condyles. Serial sections from the menisci were stained with haematoxylin and eosin (H&E) and Elastica van Gieson. Sections of the cartilage-bone cylinders were stained with H&E and safranin-O. Cartilage thickness was measured and the glycosaminoglycan content of the joint cartilage was determined using microspectrophotometry. None of the histological preparations obtained from the untreated and distracted sides showed any signs of damage to the cartilage or to the menisci. There were no significant differences between cartilage thickness and proteoglycan content of the untreated side and the lengthened side. Thus, tibial lengthening using the Ilizarov method does not appear to cause acute damage to the cartilage of the knee joint or to the menisci. © 2001 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved. [source] Is the circumferential tensile modulus within a human medial meniscus affected by the test sample location and cross-sectional area?JOURNAL OF ORTHOPAEDIC RESEARCH, Issue 6 2000Kate Lechner Quantifying the material properties of the human menisci is paramount to understanding their biomechanical functions within the knee. One important intrinsic material property governing the biomechanical functions of the meniscus is the circumferential tensile modulus. The purpose of this study was to determine if the circumferential tensile modulus of the human medial meniscus depends on the location and thickness of the sample tested. The following three hypotheses were tested: (a) the circumferential location (anterior, central, and posterior) does not significantly affect the tensile modulus, (b) the radial location (inner to outer) significantly affects the tensile modulus, and (c) the thicknes (cross-sectional area) significantly affects the tensile modulus. Test samples, whose length was oriented in parallel with the circumferential collagen fibers, were collected from different circumferential and radial locations throughout 30 human medial menisci. Samples of three different thicknesses (0.5, 1.5, and 3.0 mm) were taken from three equal groups of 10 menisci (i.e., one thickness per group). The circumferential tensile modulus was measured under quasi-statc loading. Statistical analysis showed no significant effect of the circumferential or radial location of the sample on the circumferential tensile modulus. This indicates that an overall circumferential tensile modulus may be calculated for the human medial meniscus by averaging the values determined at the various locations. However, the thickness of the test sample had a significant effect on the measured circumferential tensile modulus: the modulus varied inversely with the thickness. Thus, moduli determined from test samples that are too small in cross-sectional area overestimate the effective modulus of the tissue on the whole, and the cross-sectional area of the sample must be considered when determining a representative circumferential tensile modulus for the medial meniscus in a human knee. [source] A retrospective study of the MRI findings in 18 dogs with stifle injuriesJOURNAL OF SMALL ANIMAL PRACTICE, Issue 9 2009E. Barrett Objectives:To make an objective assessment of the usefulness of magnetic resonance imaging in the diagnosis of meniscal damage and cranial cruciate ligament disease in the canine stifle by comparing magnetic resonance imaging findings with surgical findings. Methods:Magnetic resonance images of 18 stifles from 18 dogs which had undergone magnetic resonance imaging for the investigation of stifle disease were reviewed. For every stifle, the menisci and cranial cruciate ligaments were assessed according to predetermined criteria. The magnetic resonance imaging findings were compared with the reported surgical findings and the sensitivity, specificity, positive and negative predictive values (PPV and NPV) were calculated using the surgical findings as the gold standard. Kappa analysis was used as an objective measure of agreement between surgical and magnetic resonance imaging findings. For 11 stifles, meniscal evaluation by three different observers was used to measure interobserver agreement using Kappa analysis. Results:Magnetic resonance imaging was demonstrated to be an accurate technique in the detection of meniscal injury (k=0·86), with excellent interobserver agreement (k=0·89 to 1·0). Disruption of cranial cruciate ligament continuity and an increase in ligament intensity were found to be useful criteria in the diagnosis of cranial cruciate ligament rupture. Clinical Significance:Magnetic resonance imaging offers a non-invasive alternative to exploratory surgery in the evaluation of cranial cruciate ligament and meniscal disease. [source] The chemical biomarkers C2C, Coll2-1, and Coll2-1NO2 provide complementary information on type II collagen catabolism in healthy and osteoarthritic miceARTHRITIS & RHEUMATISM, Issue 10 2007L. G. Ameye Objective Compared with wild-type (WT) mice, biglycan/fibromodulin double-deficient mice develop severe knee osteoarthritis. We undertook this study to compare type II collagen catabolism in the 2 genotypes and to compare the usefulness of 3 biomarkers of collagen degradation (C2C [also known as Col2-3/4Clong mono] as well as the peptide Coll2-1 and its nitrated form, Coll2-1NO2) for evaluating collagen catabolism in vivo. Methods In 15 WT mice and 15 biglycan/fibromodulin double-deficient mice, we determined serum levels of C2C at ages 66 and 141 days, and we determined serum levels of Coll2-1 and Coll2-1NO2 at ages 49, 81, 95, and 141 days. Expression of the biomarkers in knee sections was examined using immunohistochemistry. Results The mean concentrations of C2C and Coll2-1 were higher in biglycan/fibromodulin double-deficient mice at all time points. For C2C and Coll2-1, the ratio of the serum concentration in biglycan/fibromodulin double-deficient mice to that in WT mice (the double-deficient:WT ratio) was constant over time and was ,1.63 and ,1.15, respectively. In contrast, the double-deficient:WT ratio for Coll2-1NO2 varied and, depending on age, was >1 or <1. No significant correlation was found between the expression of the different biomarkers, except for a weak, negative correlation between Coll2-1NO2 and C2C. In both genotypes, antibodies to each biomarker labeled some fibroblasts in the tendons and menisci as well as chondrocytes above the tidemark in articular cartilage. Growth plates were unstained. For each biomarker, extracellular staining was limited to fibrocartilage areas in the tendons and menisci in all mice and was limited to some focal lesions of the cartilage in biglycan/fibromodulin double-deficient mice. Conclusion The different double-deficient:WT ratios observed with C2C, Coll2-1, and Coll2-1NO2 in the absence of any correlation between the expression of the 3 biomarkers indicate that these biomarkers give complementary, rather than redundant, information about in vivo type II collagen catabolism. [source] Increased collagen and aggrecan degradation with age in the joints of Timp3,/, miceARTHRITIS & RHEUMATISM, Issue 3 2007Solmaz Sahebjam Objective To investigate the in vivo effect of an imbalance between metalloproteinases and their inhibitors, tissue inhibitors of metalloproteinases (TIMPs), in mouse articular cartilage. Methods Hind joints of Timp3,/, and wild-type mice were examined by routine staining and by immunohistochemical analysis using antibodies specific for type X collagen and for the neoepitopes produced on proteolytic cleavage of aggrecan (, VDIPEN and , NVTEGE) and type II collagen. The neoepitope generated on cleavage of type II collagen by collagenases was quantitated in sera by enzyme-linked immunosorbent assay. Results Articular cartilage from Timp3 -knockout animals (ages ,6 months) showed reduced Safranin O staining and an increase in ,VDIPEN content compared with cartilage from heterozygous and wild-type animals. There was also a slight increase in , NVTEGE content in articular cartilage and menisci of Timp3,/, animals. Chondrocytes showed strong pericellular staining for type II collagen cleavage neoepitopes, particularly in the superficial layer, in knockout mice. Also, there was more type X collagen expression in the superficial zone of articular cartilage, especially around clusters of proliferating chondrocytes, in the knockout mice. More type II collagen cleavage product was found in the serum of Timp3,/, mice compared with wild-type animals. This increase was significant in 15-month-old animals. Conclusion These results indicate that TIMP-3 deficiency results in mild cartilage degradation similar to changes seen in patients with osteoarthritis, suggesting that an imbalance between metalloproteinases and TIMP-3 may play a pathophysiologic role in the development of this disease. [source] High resolution imaging of the knee on 3-Tesla MRI: A pictorial reviewCLINICAL ANATOMY, Issue 5 2008N. Griffin Abstract The recent introduction of 3-Tesla MRI offers substantial advances in musculoskeletal applications. High resolution images can now be obtained with shorter data acquisition times. This article provides a pictorial review of 3-Tesla imaging in the knee with descriptions of both normal anatomy and the more common lesions involving the menisci, ligaments, and articular cartilage. A discussion of the issues associated with imaging at higher field strengths is also included. Clin. Anat. 21:374,382, 2008. © 2008 Wiley-Liss, Inc. [source] A cranial intercondylar arthroscopic approach to the caudal medial femorotibial joint of the horseEQUINE VETERINARY JOURNAL, Issue 1 2009T. Muurlink Summary Reason for performing study: Current noninvasive techniques for imaging the soft tissue structures of the stifle have limitations. Arthroscopy is commonly used for the investigation and treatment of stifle pain. Cranial and caudal arthroscopic approaches to the femorotibial joints are used. However, complete examination of the axial aspect of the medial femorotibial joint (MFTJ) is not possible currently. Objective: To develop a cranial approach to the caudal pouch of the MFTJ and to assess whether it would allow a more complete examination of the compartment and facilitate the caudomedial approach. Method: The regional anatomy was reviewed and the technique developed on cadavers. A series of nonrecovery surgeries were performed to evaluate the procedure, which was then used in 7 clinical cases. Advantages compared to existing techniques and complications encountered were recorded. Results: Successful entry into the caudal pouch of the MFTJ was achieved in 20 of 22 cadaver legs, 8 of 8 joints of nonrecovery surgery horses and 6 of 7 clinical cases operated. The caudal ligament of the medial meniscus could be visualised, along with other axial structures of the caudal joint pouch. The technique was used to facilitate a caudomedial approach and allowed better triangulation within the joint space. Complications were minor and included puncture of the caudal joint capsule and scoring of the axial medial femoral condyle. Conclusions and potential relevance: It is possible to access the caudal pouch of the MFTJ arthroscopically using a cranial intercondylar approach. The technique has advantages when compared to existing techniques and is associated with few significant complications. A cranial approach to the caudal pouch of the MFTJ could complement existing techniques and be useful clinically. [source] Contact Angle Analysis During the Electro-oxidation of Self-Assembled Monolayers Formed by n -OctadecyltrichlorosilaneADVANCED FUNCTIONAL MATERIALS, Issue 19 2010Nicole Herzer Abstract The electrochemical oxidation process of self-assembled monolayers formed by n -octadecyltrichlorosilane (OTS) molecules on silicon wafers has been studied in a droplet of water by means of in situ water contact angle measurements. The application of different bias voltages between the substrate and a counter electrode placed into the droplet resulted in changes of the chemical nature of the monolayer, which yielded a significant alteration of the surfaces properties. Due to the changes of the wetting properties of the monolayer during the electro-oxidation process a change in the contact angles of the water droplet is concomitantly observed. This allows the in situ monitoring of the electro-oxidation process for large modified areas of several millimeters in diameter. The chosen approach represents an easy way to screen the major parameters that influence the oxidation process. Afterwards, the oxidized regions are characterized by Fourier-transform infrared (FT-IR) spectroscopy, X-ray photoelectron spectroscopy (XPS) measurements, and atomic force microscopy (AFM) investigations to obtain more information about the electro-oxidation process. The observations are correlated to experimental results obtained for oxidations performed on a smaller dimension range in the water meniscus of a conductive, biased AFM tip. A good correlation of the results in the different dimension ranges could be found. [source] Dip-Pen Nanolithography Using the Amide-Coupling Reaction with Interchain Carboxylic Anhydride- Terminated Self-Assembled Monolayers,ADVANCED FUNCTIONAL MATERIALS, Issue 8 2006S. Chi Abstract Herein we report on a new type of dip-pen nanolithography (DPN), which utilizes an interfacial organic reaction,the amide-coupling reaction,between chemically activated surfaces and amine ink molecules transferred from an atomic force microscopy tip. As a representative of the chemically activated surfaces that could react with amine compounds, we formed a self-assembled monolayer terminating in interchain carboxylic anhydride (ICA) groups on gold, and generated chemically derived nanopatterns using alkylamines as ink molecules. Amine inks showed diffusive behavior similar to thiol inks on gold in conventional DPN, and the pattern sizes were controlled by changing the tip dwell times. In addition, nanopatterns of hydrolyzed ICAs were generated by taking advantage of the participation of the water meniscus in the DPN process and the chemical nature of the ICAs. [source] Meniscus-Controlled Continuous Fabrication of Arrays and Rolls of Extremely Long Micro- and Nano-Fibers,ADVANCED MATERIALS, Issue 4 2008P. Suryavanshi A direct-write nanomanufacturing technique is developed for the high-speed, continuous fabrication of micro- and nano-fibers made of soluble ionic solids in a low-humidity ambient environment. The process is based on the fast evaporation of solvent and the precipitation of solute in the nanoscale meniscus. Freestanding nanofibers, suspended or stacked nanofiber arrays, and even a continuously wound microfiber roll with a fiber length over 40 cm are fabricated. [source] Bottom,Up Fabrication of Carbon-Rich Silicon Carbide Nanowires by Manipulation of Nanometer-Sized Ethanol Menisci,ADVANCED MATERIALS, Issue 12 2005M. Tello A nanometer-sized ethyl alcohol meniscus induced between a conductive atomic force microscope tip and a silicon surface (see Figure) allows the fabrication of nanodots or nanowires of SiCx at a predetermined position on the substrate. The meniscus size and kinetic parameters control the nanostructure size. [source] The cells of the rabbit meniscus: their arrangement, interrelationship, morphological variations and cytoarchitectureJOURNAL OF ANATOMY, Issue 5 2000MARIE-PIERRE HELLIO LE GRAVERAND Four major morphologically distinct classes of cells were identified within the adult rabbit meniscus using antibodies to cytoskeletal proteins. Two classes of cell were present in the fibrocartilage region of the meniscus. These meniscal cells exhibited long cellular processes that extended from the cell body. A third cell type found in the inner hyaline-like region of the meniscus had a rounded form and lacked projections. A fourth cell type with a fusiform shape and no cytoplasmic projections was found along the superficial regions of the meniscus. Using a monoclonal antibody to connexin 43, numerous gap junctions were observed in the fibrocartilage region, whereas none were seen in cells either from the hyaline-like or the superficial zones of the meniscus. The majority of the cells within the meniscus exhibited other specific features such as primary cilia and 2 centrosomes. The placement of the meniscal cell subtypes as well as their morphology and architecture support the supposition that their specific characteristics underlie the ability of the meniscus to respond to different types of environmental mechanical loads. [source] Oxygen Tension Regulates the Expression of ANK (Progressive Ankylosis) in an HIF-1-Dependent Manner in Growth Plate Chondrocytes,,JOURNAL OF BONE AND MINERAL RESEARCH, Issue 11 2009Raihana Zaka Abstract The proximal promoter region of ANK, a gene that codes for a protein that regulates the transport of inorganic pyrophosphate, contains two hypoxia responsive elements (HREs); therefore, we studied the expression and function of ANK at different oxygen tensions. ATDC5 and N1511 clonal chondrocytic cells were cultured in either hypoxia (2% O2) or normoxia (21% O2). Transcript and protein levels of ANK were depressed in hypoxic conditions, as were levels of extracellular pyrophosphate (ePPi). To determine whether HIF-1 was involved in the oxemic response, Hif-1, knockdown cells were exposed to varying oxygen conditions and ANK expression was assessed. Knockdown of Hif-1, resulted in low levels of expression of ANK in hypoxia and normoxia. Chromatin immunoprecipitation (ChIP) assays explored the binding of Hif-1, to ANK HREs and showed that Hif-1, is able to bind to the HREs of ANK more avidly in normoxia than in hypoxia. Furthermore, functional studies of Hif-1, activity using luciferase reporter assays of wildtype and mutagenized HREs showed that only HRE-1 binds Hif-1, in normoxia. Expression of ANK in growth plate and articular cartilage was low in hypoxic regions of the tissues, and higher levels of ANK expression were observed in the synovium and meniscus in regions that have a normally higher oxygen tension. The data suggest that ANK expression and function in vitro and in vivo are repressed in hypoxic environments and that the effect is regulated by HIF-1. [source] Normal ultrasound anatomy of the triangular fibrocartilage of the wrist: A study on cadavers and on healthy subjectsJOURNAL OF CLINICAL ULTRASOUND, Issue 4 2009Lionel Pesquer MD Abstract Purpose. To report the normal sonographic anatomy of the triangular fibrocartilage (TFC) of the wrist in cadavers and volunteers. Method. Five hands from cadavers were examined sonographically before and after wrist dissection, during which the TFC was marked with surgical wires. Twenty volunteers without wrist limitation or pain, and without any history of wrist disease or inflammatory arthritis (mean age, 26 years (range,19,45 years) were also examined. Results. Sonograms showed that the meniscus and the TFC were clearly separated. The meniscus appeared as a triangular structure that was homogeneous and slightly hyperechoic. Compared with the meniscus, the TFC appeared hypoechoic. The same patterns were observed for cadavers and volunteers. In 3 volunteers (15%), the TFC was not visualized. Conclusions. Using high-resolution ultrasound systems, the TFC can be separated from meniscus. However, vizualization of the TFC remains limited due to its deep location and the presence of acoustic shadowing from bony structures. © 2008 Wiley Periodicals, Inc. J Clin Ultrasound 2009 [source] Is there a role for sonography in the diagnosis of tears of the knee menisci?JOURNAL OF CLINICAL ULTRASOUND, Issue 8 2002Roberto Azzoni MD Abstract Purpose The aim of this study was to investigate the usefulness of sonography in diagnosing tears of the knee menisci. Methods In this retrospective study, we reviewed the sonographic examinations of the knees of 321 patients diagnosed with a torn meniscus on the basis of clinical findings. Of the 321 knees imaged, 216 were also examined using MRI or CT. Arthroscopic meniscectomy was performed on 126 knees. Results MRI or CT did not confirm 48% (71 cases) of the positive sonographic diagnoses (ie, false positives) and 72% (50 cases) of the negative sonographic diagnoses (ie, false negatives). Thus, the sonographic diagnosis was correct in 95 cases (44%) and incorrect in 121 cases (56%), yielding low rates of sensitivity (60%) and specificity (21%). Among the 126 cases in which arthroscopic meniscectomy was performed, arthroscopy confirmed 100% of the MRI or CT diagnoses of meniscal tears. Conclusions Our results indicate that sonography is not accurate enough to be used as the only imaging modality for diagnosing tears of the knee menisci. © 2002 Wiley Periodicals, Inc. J Clin Ultrasound 30:472,476, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI: 10.1002/jcu.10106 [source] Medial meniscus posterior root attachment injury and degeneration: MRI findingsJOURNAL OF MEDICAL IMAGING AND RADIATION ONCOLOGY, Issue 4 2006AO Jones Summary The posterior root attachment of the medial meniscus is readily identifiable on MRI. Unless specifically reviewed, injuries involving this structure may be overlooked. Significant meniscal root pathology may cause functional incompetence of the meniscus, with consequent early onset cartilage degeneration and osteoarthritis. This review article emphasizes the importance of positive identification of an intact meniscal root and illustrates the known association of meniscal root injury or tear with medial extrusion of the medial meniscus by greater than 3 mm beyond the joint margin. [source] Hepatitis C virus does not infect muscle, the intervertebral disk, or the meniscus in patients with chronic hepatitis CJOURNAL OF MEDICAL VIROLOGY, Issue 12 2007Javier Bartolomé Abstract Chronic infection with hepatitis C virus (HCV) is associated with several extrahepatic manifestations, including neuromuscular and joint disorders, and HCV RNA has been detected in muscle fibers of patients with myosistis and chronic hepatitis C. However, whether HCV infects muscle cells in patients without myosistis is unknown. The presence of HCV in other sites of the musculoskeletal system has not been investigated. In the present study the presence of HCV RNA was sought in muscle (2 cases), intervertebral disk (1 case) and meniscus (1 case) samples from patients with chronic hepatitis C. HCV RNA was not detected by reverse transcription and real-time polymerase chain reaction in any of the samples tested. In conclusion, the results do not support a direct role of HCV in musculoskeletal disorders associated with chronic hepatitis C. J. Med. Virol. 79:1818,1820, 2007. © Wiley-Liss, Inc. [source] Mesenchymal stem cells derived from synovium, meniscus, anterior cruciate ligament, and articular chondrocytes share similar gene expression profilesJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 4 2009Yuko Segawa Abstract Mesenchymal stem cells (MSCs) can be obtained from various tissues, and contain common features. However, an increasing number of reports have described variant properties dependent of cell sources. We examined (1) whether MSCs existed in several intraarticular tissues, (2) whether gene expression profiles in intraarticular tissue MSCs closely resembled each other, and (3) whether identified genes were specific to intraarticular tissue MSCs. Human synovium, meniscus, intraarticular ligament, muscle, adipose tissue, and bone marrow were harvested, and colony-forming cells were analyzed. All these cells showed multipotentiality and surface markers typical of MSCs. Gene profiles of intraarticular tissue MSCs and chondrocytes were closer to each other than those of extraarticular tissues MSCs. Among three characteristic genes specific for intraarticular tissue MSCs, we focused on proline arginine-rich end leucine-rich repeat protein (PRELP). Higher expression of PRELP was confirmed in chondrocytes and intraarticular tissue MSCs among three elderly and three young donors. Synovium MSCs stably expressed PRELP, contrarily, bone marrow MSCs increased PRELP expression during in vitro chondrogenesis. In conclusion, MSCs could be isolated from various intraarticular tissues including meniscus and ligament, gene expression profiles of intraarticular tissue MSCs closely resembled each other, and the higher expression of PRELP was characteristic of intraarticular tissue MSCs. © 2008 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 27: 435,441, 2009 [source] | ||||||||||||||||||||||