No abstract available.
Cartilage, Articular*

Autologous chondrocyte implantation (ACI) is a significant technique that has gained widespread use for the treatment of focal articular cartilage damage. Since its inception in 2004, the Tissue Engineering Group (TEG) of the Faculty of Medicine, University Malaya has been dedicated to carrying out extensive research on this cell-based therapy. The objective of this report, comprising one clinical case report, six animal studies and one laboratory study, is to summarise and discuss TEG’s key findings. On the whole, we observed that the ACI technique was effective in regenerating hyaline-like cartilage in treated defects. Autologous chondrocytes and mesenchymal stem cells (MSC) were found to produce comparable tissue repair irrespective of the state of MSC differentiation, and the use of alginate-based scaffolding and oral pharmacotherapy (Glucosamine and Chondroitin Sulphate) was shown to enhance ACI-led tissue repair. ACI is suggested to be an efficient therapeutic option for the treatment of articular cartilage defects of the knee.
Cartilage, Articular

PURPOSE: To determine the correlation of laminae of different signal intensities (SI) of articular cartilage,as seen on magnetic resonance (MR) imaging with histologic layes, using artificially constructed landmarks. MATERIALS AND METHODS: For a landmark that can exactly correlate the cartilage specimen with the MR image, five'V'-shaped markings of different depths were made on the surface of bovine patella. Both T1-weighted (TR/TE :300/14) and FSE T2-weighted images (TR/TE : 2000/53) were obtained on a 1.5T system with high gradient echostrength (25mT/m) and a voxel size of 78x78x2000 micrometer. Images were obtained with 1) changed frequency-encodingdirections on T1-weighted study, and 2) changed readout gradient strength (x2, x1/2) on T2-weighted sequence.Raw image data were transferred to a workstation and signal intensity profile was generated for each image. 1 : 1correlation of histologic specimens and MR images was performed. RESULTS: Line Profile through the cartilageshowed few peaks, suggesting changes in signal intensity profile in the cartilage. On the basis of artificiallandmarks, the histologic zone was accurately identified. The histologic tangential and transitional zonescorrelated with superficial high SI on T1WI, as well as high and low SII on T2WI. On T1WI, the radial zonecorrelated with a lamina of intermediate SI, and on T2WI, with a lamina for which SI gradually decreased from highto low. Additional well-defined low and intermediate SI bands were noted on bovine T1WI in the lower radial zone.In both T1 and T2 studies, calcified cartilage layers were of low SI. On T1-weighted study, changes in thedirection of frequency gradient did not lead to changes in the laminae. The alteration of readout gradientstrengths did not result in an inversely proportional difference in the thickness of the laminae. These becamemore distinct thus ruling out chemical shift and susceptibility artifacts. CONCLUSION: The laminated appearanceof articular cartilage, as seen on spin echo and fast spin-echo MR images, correlated with histologic layersrather than susceptibility or chemical shift artifacts.
Artifacts ; Cartilage* ; Cartilage, Articular ; Patella

Articular cartilage lesions can be a debilitating disease resulting in the development of osteoarthritis (OA). In recent years, mesenchymal stem cell (MSC) strategies combined with the microfracture technique are emerging as a powerful tool for cartilage repair. Even though there are some successful reports of MSCs treatments, many aspects have to be optimized such as best cell source and application method. The interest in this field is growing and randomized controlled trials are needed to show the potential of MSC treatment.
Cartilage ; Cartilage, Articular* ; Mesenchymal Stromal Cells* ; Osteoarthritis

No abstract available.
Cartilage, Articular* ; Mandibular Condyle* ; Replantation*

No abstract available.
Cartilage, Articular* ; Mandibular Condyle* ; Replantation*

The small molecule nutrients and cell growth factors required for the normal metabolism of chondrocyte mainly transport into the cartilage through free diffusion. However, the specific mass transfer law in the cartilage remains to be studied. In this study, using small molecule rhodamine B as tracer, the mass transfer models of cartilage were built under different pathways including surface pathway, lateral pathway and composite pathway. Sections of cartilage at different mass transfer times were observed by using laser confocal microscopy and the transport law of small molecules within different layers of cartilage was studied. The results showed that rhodamine B diffused into the whole cartilage layer through surface pathway within 2 h. The fluorescence intensity in the whole cartilage layer increased with the increase of mass transfer time. Compared to mass transfer of 2 h, the mean fluorescence intensity in the superficial, middle, and deep layers of cartilage increased by 1.83, 1.95, and 3.64 times, respectively, after 24 h of mass transfer. Under lateral path condition, rhodamine B was transported along the cartilage width, and the molecular transport distance increased with increasing mass transfer time. It is noted that rhodamine B could be transported to 2 mm away from cartilage side after 24 h of mass transfer. The effect of mass transfer under the composite path was better than those under the surface path and the lateral path, and especially the mass transfer in the deep layer of cartilage was improved. This study may provide a reference for the treatment and repair of cartilage injury.
Cartilage, Articular ; Rhodamines/pharmacology* ; Chondrocytes

PURPOSE: The purpose of this study was to evaluate the effects of magnetization transfer contrast(MTC) andfat-suppression(FS) in variable spin-echo and gradient-echo sequences for articular cartilage imaging and todetermine the optimal pulse sequences. MATERIALS AND METHODS: Using variable 7-pulse sequences, the knees of 15pigs were imaged Axial images were obtained using proton density and T2-weighted spin-echo (PDWSE and T2WSE),turbo spin-echo (TSE), multiplanar gradient-echo (MPGR), and 3D steady-state gradient-echo (3DGRE) sequences, andthe same pulse sequences were then repeated using MTC. Also T1-weighted spin-echo(T1WSE) and 3D spoiledgradient-echo(3DSPGR) images of knees were also acquired, and the procedure was repeated using FS. For each knee,a total of 14 axial images were acquired, and using a 6-band scoring system, the visibility of and thevisibilities of the the articular cartilage was analyzed. The visual effect of MTC and FS was scored using a4-band scale. For each image, the signal intensities of articular cartilage, subchondral bone, muscles, and salinewere measured, and signal-to-noise ratios(SNR) and contrast-to-noise ratios(CNR) were also calculated. RESULTS: Visibility of the cartilage was best when 3DSPGR and T1WSE sequences were used. MTC imaging increased the negativecontrast between cartilage and saline, but FS imaging provided more positive contrast. CNR between cartilage andsaline was highest when using TSE with FS(-3 5 1 . 1 +/-15.3), though CNR between cartilage and bone then fell to-1 4 . 7 +/-10.8. In MTC imaging using MPGR showed the greatest increase of negative contrast between cartilage andsaline(CNR change=-74.7); the next highest was when 3DGRE was used(CNR change=-34.3). CNR between cartilage andbone was highest with MPGR(161.9 +/-17.7), but with MTC, the greatest CNR decrease(-81.8) was observed. Thegreatest CNR increase between cartilage and bone was noted in T1WSE with FS. In all scans, FS provided acartilage-only positive contrast image, though the absolute value of CNR was lower than that of MTC imaging. CONCLUSION: The most prominent effects of MTC and FS were seen in MPGR and T1WSE, respectively, though forcartilage, optimal high signal intensity and contrast can be achieved using 3DGRE with MTC, and 3DSPGR with FS.
Cartilage ; Cartilage, Articular* ; Knee ; Magnetic Resonance Imaging* ; Muscles ; Protons

BACKGROUND: Recent advance in tissue engineering in the biomedical field shed light on the replacement or regeneration of various organs with synthetic substitutes. Currently emerging cartilage tissue engineering therapies involve artificial cartilage fabricated from three dimensional cultures using appro-priate scaffolds. It is mandatory to expand or proliferate the chondrocytes in vitro to prepare the artificial cartilage. The purpose of this study was to find out the most favorable culture conditions for chon-drocyte viability in vitro. METHODS: Articulr chondrocytes or cartilage explants were isolated from the patellofemoral groove of adult pigs. And then we standardized the size and thickness of the cartilage explants as well as preparing alginate-chondrocyte beads for three-dimensional cultures. The cartilage explants, including 10% fetal bovine serum for 10 days, 36 days and passage 6. Cellualr viability was measured by methylthiazol tetrazolium (MTT) assay on monolayer, alginate bead and cartilage explant. SPSS 11.5 was used for data anaylsis. RESULTS: Chondrocytes cultured on monolayers in vitro showed no significant difference in cellular viability until passage 6 following isolation from the patellofemoral groove of adult pigs (P>0.05, n=4). Chondrocyte viability was markedly increased by day 16 both in the monolayer (148%) and three dimensional cultures (245%), and then slightly decreased 126% and 200%, respectively, at day 36. Three dimensional cultures using alginate bead were more favorable for chodrocyte viability than monolayer culture in chondrocyte primary culture (P=0.003, n=6). Chondrocyte viability in the algi-nate bead was increased 300% during 36 days' incubation period (P=0.001, n=3). Cellular viability in the cartilage explant culture was decreased after day 4 in both MTT score (P=0.022, n=10) and MTT OD (P=0.039, n=10). CONCLUSIONS: Three dimensional cultures using alginate bead were the most favorable for chon-drocyte viability in chondrocyte primary cultures.
Adult ; Cartilage ; Cartilage, Articular* ; Chondrocytes* ; Humans ; Regeneration ; Swine ; Tissue Engineering

PURPOSE: The objective of this study was to investigate the effects of radiofrequency energy on human chondrocyte viability, and to correlate confocal laser microscopy fluorescence to sulfate uptake and to the histological integrity of articular cartilage. MATERIALS AND METHODS: The chondroplasty procedure for chondromalacic articular cartilage was performed using a 3.0-mm ArthroWand (Arthroscopic Electrosurgery System, ArthroCare Corporation) on fresh human articular cartilage. Radiofrequency energy was applied to the cartilage surface through the probe at a velocity of 10-mm per second in contact and non-contact mode. Three power settings were used. The treated cartilage was analyzed for chondrocyte viability by confocal laser microscopy and (35)S uptake. RESULTS: Confocal laser microscopy demonstrated partial-thickness chondrocyte death irrespective of treatment method. No mode of treatment or radiofrequency energy power setting resulted in full-thickness chondrocyte death. The depth of cartilage ablation was increased in the treated areas in contact mode in proportion to the power level and the time of treatment. No statistically significant difference in radiolabeled sulfate uptake of the specimens was observed with respect to the treatment modes and power settings. CONCLUSION: The extent of chondrocyte death by radiofrequency energy was not as significant as reported previously when the probe was moved at the speed of 10 mm/sec. Radiofrequency energy may be useful to treat chondromalacic cartilage in a contact mode using a proper energy level and delivery time.
Cartilage ; Cartilage, Articular* ; Chondrocytes* ; Electrosurgery ; Fluorescence ; Humans* ; Microscopy, Confocal