BACKGROUND:Osteoarthritis,often accompanied by cartilage abnormal signal transduction,suggesting that intracellular signal transduction may play an important role in osteoarthritis genesis and development.OBJECTIVE:To review recent advances in the research of Notch signaling pathway,and explore the mechanisms of chondrogenic differentiation of bone marrow mesenchymal stem cells and its role in cartilage development and chondrogenesis.To analysis the role of dysregulated Notch signaling in the development of osteoarthritis.METHODS:Pubmed was undertaken to identify the relevant articles published from March 1919 to February 2009 with the key words of"Notch signaling pathway,osteoarthritis,chondrocytes,chondrogenesis,bone marrow stem cells"in English.Simultaneously,CNKI Database was searched for relevant articles published from February 2004 to September 2008 with the key words of"Notch signaling pathway,osteoarthritis,chondrocytes,chondrogenesis,bone marrow stem cells"in Chinese Articles with the Notch signaling pathway-related research,Notch signaling pathway of bone marrow-derived mesenchymal stem cells,differentiation of cartilage relative to the mechanism studies,and the Notch signaling pathway disorders and osteoarthritis research were included,Reproducibility articles were excluded Development regulation of articular cartilage and cartilage cell proliferation were considered as evaluation indexes.RESULTS AND CONCLUSION:Of 632 articles retrieved,30 were included in our study according to the inclusive and exclusive criteria.The Notch pathway is a highly consewed signaling mechanism involved in many processes determining cell fate during development and maintenance of homeostasis of mature tissues in the adult organism.Activation of Notch occurs following Notch receptor/ligand engagement upon cell-cell contact,which initiates translocation of the Notch intracellular domain to the nucleus and activation of target genes.It has been demonstrated that the Notch signaling plays an important role in regulating articular cartilage development and chondrocyte proliferation and differentiation In recent studies abnormality of notch signaling was also found in disease,which suggests that notch signaling is involved in osteoarthritis initiation and development.Further study of the specific mechanism of notch signaling in the initiation and development of osteoarthritis will enable us to develop targeted approaches in the treatment of osteoarthritis,thus bring more strategies in the future treatment of osteoarthritis.

OBJECTIVEThis work investigated mesenchymal stem cells (MSCs) modified with Runt-related transcription factor 2 (Runx2) therapy for bone regeneration in rabbit mandibular distraction osteogenesis.

METHODSForty-eight New Zealand mature white rabbits were randomly divided into three groups after the rabbit model of mandibular distraction osteogenesis was established: reconstruction plasmid modified with Runx2 (group A), plasmid without Runx2 (group B), and the same dose of saline as control (group C). At the fifth day of distraction phase, MSCs with reconstruction plasmid modified with adv-hRunx2-gfp were injected into the distraction gap of group A. MSCs with reconstruction plasmid modified with adv-gfp was injected into the distraction gap of group B, whereas group C was injected with the same dose of saline. At 8 weeks after injection, all animals were sacrificed, and the distracted mandibles were harvested. The general imaging histological observation and three-point bending test were used for evaluation.

RESULTSCT plain scan and histological analysis confirmed that the amount of new bone forming in the distraction gap of group A was significantly higher than those in groups B and C. Dual-energy X ray and three-point bending test results also showed that the bone mineral density, bone mineral content, and maximum load of the distraction gap of group A were significantly higher than those of groups B and C (P<0.01).

CONCLUSIONRunx2-ex vivo gene therapy based on MSCs can effectively promote the bone regeneration in rabbit mandibular distraction osteogenesis and shorten the stationary phase. Therefore, reconstruction of craniofacial fracture would be a valuable strategy

Absorptiometry, Photon ; Animals ; Bone Density ; Bone Regeneration ; physiology ; Core Binding Factor Alpha 1 Subunit ; genetics ; pharmacology ; Genetic Therapy ; Mandible ; physiology ; surgery ; Mesenchymal Stem Cell Transplantation ; methods ; Mesenchymal Stromal Cells ; Osteogenesis ; genetics ; Osteogenesis, Distraction ; methods ; Plasmids ; Rabbits ; Random Allocation ; Transcription Factors ; genetics ; physiology ; Treatment Outcome

BACKGROUND:During the healing of fractures, removal of sciatic nerve can result in insufficient mechanical rigidity of newborn woven bone. However, there are less reports concerning the denervation effects during distraction osteogenesis. OBJECTIVE:To observe the effect of removal of the sciatic nerve on bone regeneration and the expression of Runt-related transcription factor 2 (Runx2) protein during distraction osteogenesis in a rabbit model. METHODS:Twenty-four adult male New Zealand rabbits were selected and underwent left tibial osteodistraction to construct animal models of distraction osteogenesis. Before distraction, the animals were randomly divided into group R (resecting the left sciatic nerve) and group I (intact left sciatic nerve). Six weeks after completion of distraction, the animals were kil ed and the lengthened tibias were harvested for radiography, three-dimensional CT reconstruction, histological evaluation, connectivity density (Conn.D) evaluation. RESULTS AND CONCLUSION:New regenerated bone was present and Runx2 protein was expressed in the distraction gaps of al animals at the end of the study, as revealed by radiography, three-dimensional CT reconstruction, and histological observation. However, less new bone formation and a lower degree of mineralization and expression of Runx2 protein were observed in group R compared with group I. The results suggest that the denervation appears to have an inhibitory effect on bone formation and the expression of Runx2 protein during distraction osteogenesis.

Objective:To introduce a 2-stage treatment protocol for the management of temporomandibular joint ankylosis with sec-ondary deformities in adults.Methods:24 adult patients (9 males and 15 female)(30 joints)at the average age of 26.1 years un-derwent TMJ reconstruction as the initial surgery,followed by orthodontic treatment and correction of secondary deformities as the sec-ond surgery.Clinical outcome was assessed based on maximal incisal opening,radiography and medical photography.Results:Skele-tal deformities were significantly improved in all patients,satisfactory occlusion was achieved with the orthodontic treatment,average maximal incisal opening increased from 3.4 mm to 32.5 mm(P <0.05).Conclusion:The 2-stage treatment protocol is an effective approach for management of TMJ ankylosis with secondary deformities in adult patients.

Objective To assess the value of contrast-enhanced ultrasonography (CEUS ) in diagnosing BI-RADS 4 breast lesion.Methods The CEUS findings of 79 breast lesions of BI-RADS 4 were analyzed,and the CEUS diagnosis was made according to our preliminary study results.Histology results were served as golden reference.Results Of all the 79 breast lesions that were confirmed by histopathology results,36 were malignant and 43 were benign.The differences of morphologic features of area variety, margin,heterogeneous or homogeneous distribution between benign and malignant lesions were significant (P < 0.05 ).The area under ROC curve of correction BI-RADS classification in the diagnosis of breast cancer was 0.938,and it was significantly higher than that of the BI-RADS classification (0.889,Z =2.209, P =0.0272).Conclusions CEUS can improve the diagnostic accuracy of breast lesions preoperatively.

Orthognathic surgery and temporomandibular joint (TMJ) surgery are two relatively independent disciplines in oral and maxillofacial surgery. Dentofacial deformities and TMJ diseases commonly coexist. The diagnosis and treatment of the diseases with coexisting dentofacial deformities and TMJ disorders is complex. Thus it is very important to comprehensively understand the common characteristics of orthognathic and TMJ surgery, which places a greater demand on oral and maxillofacial surgeons. The present work focuses on our thinking on common characteristics of TMJ and orthognathic surgery based on the managements of these diseases.

The teaching of orthognathic surgery is difficult because it is complex and emphasizes the combination of theory and practice. The traditional teaching method focuses on theoretical teaching, but due to the limitation of conditions, it is difficult for students to master the operation. In this paper, we apply the digital three-dimensional surgical simulation system combined with 3D printing in specialist training of orthognathic surgery. Digital software and 3D printing are applied in the theoretical teaching, surgical operation, summary and reflection to combine practical teaching with theoretical teaching, so as to stimulate the subjective initiative of the students. The results showed that the teaching evaluation of the experimental group [(3.89±0.84) points] was better than that of the control group [(2.91±1.21) points]. The application of digital three-dimensional surgical simulation system combined with 3D printing has achieved satisfactory results.

Dento-maxillofacial deformity refers to an abnormal relationship of the volume or shape of the upper and lower jaw bones with the other bones of the craniofacial area. Its correction mainly involves hard tissues, such as the jaws and teeth. In recent years, digital techniques based on virtual surgery, real-time navigation, and 3D printing have developed rapidly in the area of craniomaxillofacial surgery. Digital technology has advantages for preoperative diagnosis, surgical plan formulation, surgical simulation, intraoperative navigation, effect prediction, doctor-patient communication, and young physician training. The Department of Orthognathic and TMJ Surgery of West China Hospital of Stomatology, Sichuan University, has conducted digitized diagnosis and treatment of dento-facial deformities since 2008 and has established a digital center for the treatment of dentofacial deformities based on equipment such as spiral CT, dental arch laser scanners, facial 3D cameras, virtual surgery software, 3D printers, and sleep-breathing monitoring. The result is a diagnostic and treatment protocol for dentofacial deformity specific to the characteristics of the population of West China. This article combines the latest domestic and foreign literature and comprehensively introduces the application of digital technology for the diagnosis and treatment of dental and maxillofacial deformities.

The temporomandibular joint(TMJ)is the critical functional unit in the human stomatognathic system.Damage of the TMJ causes orofacial dysfunction and secondary jaw deformities,leading to seriously decreased quality of life in patients.The TMJ prosthetic replacement is an important treatment method for severe joint destruction because of its remarkable advantages compared with other methods.In recent years,this technique has gradually attracted wide attention in China,but it has not been popularized on a large scale in our country because of several limitations.Thus,in this study,the clinical experience of patients with TMJ prosthetic replacement in clinical units was summarized,and the treatment principles,treatment processes,and technical advantages were systematically discussed,aiming to promote the popularization and application of TMJ prosthetic replace-ment in China.

Objective:To comprehensively investigate the biomechanical properties of the temporomandibular joint (TMJ) disc and to perfect the mechanical testing system of the TMJ disc by conducting tests of compression, tension, cyclic compression, cyclic tension, creep and friction.Methods:Fifteen fresh goat heads (weighing 2.5-3.0 kg) were purchased from the market. They were all ordinary goats (9-12 months old, body weighing 18-21 kg) regardless of gender. Bilateral articular discs (a total of 30) were dissected within 30 minutes after execution. According to the national standard for mechanical testing of viscoelastic materials, fresh TMJ disc specimens of goat were prepared and tests were carried out in physiological conditions. The universal mechanical testing machine was utilized to test biomechanical properties of TMJ discs.Results:The compressive modulus of TMJ discs was (8.41±2.12) MPa and the tensile modulus was (9.54± 3.26) MPa. The mechanical characteristics would be irreversibly altered once the load exceeded the physiological range. In addition, it underwent apparent creep relaxation under continuous strain (0.5 MPa or 3.0 MPa) and the surface friction coefficient of the TMJ discs (0.015+0.011) was much lower than that of general viscoelastic materials.Conclusions:The TMJ disc was a bio-viscoelastic structure with excellent tensile and compressive properties and its surface was extremely smooth in wet conditions.