Status quo and reform proposals of dental doctoral education / 中华医学教育探索杂志

Chinese dental doctoral education has developed multiple lengths of schooling, including eight-year programme, five-year direct doctoral programme, five-year master-doctor combined programme and three-year doctoral programme. The review summarizes the development of the lengths of schooling of Chinese dental doctoral education, compares and analyzes different modes of education and their outcomes. In order to further construct the Chinese dental doctoral education, it's strongly suggested to set a medical-scientist training programme, to promote the double-track system and to deepen the collaborative reform of medical and educational cooperation to train more outstanding talents for the future development of stomatology in China.

Micromechanical interlocking structure at the filler/resin interface for dental composites: a review / 国际口腔科学杂志·英文版

Dental resin composites (DRCs) are popular materials for repairing caries or dental defect, requiring excellent properties to cope with the complex oral environment. Filler/resin interface interaction has a significant impact on the physicochemical/biological properties and service life of DRCs. Various chemical and physical modification methods on filler/resin interface have been introduced and studied, and the physical micromechanical interlocking caused by the modification of fillers morphology and structure is a promising method. This paper firstly introduces the composition and development of DRCs, then reviews the chemical and physical modification methods of the filler/resin interface, mainly discusses the interface micromechanical interlocking structures and their enhancement mechanism for DRCs, finally give a summary on the existing problems and development potential.

The osteogenesis of Ginsenoside Rb1 incorporated silk/micro-nano hydroxyapatite/sodium alginate composite scaffolds for calvarial defect / 国际口腔科学杂志·英文版

Ginsenoside Rb1, the effective constituent of ginseng, has been demonstrated to play favorable roles in improving the immunity system. However, there is little study on the osteogenesis and angiogenesis effect of Ginsenoside Rb1. Moreover, how to establish a delivery system of Ginsenoside Rb1 and its repairment ability in bone defect remains elusive. In this study, the role of Ginsenoside Rb1 in cell viability, proliferation, apoptosis, osteogenic genes expression, ALP activity of rat BMSCs were evaluated firstly. Then, micro-nano HAp granules combined with silk were prepared to establish a delivery system of Ginsenoside Rb1, and the osteogenic and angiogenic effect of Ginsenoside Rb1 loaded on micro-nano HAp/silk in rat calvarial defect models were assessed by sequential fluorescence labeling, and histology analysis, respectively. It revealed that Ginsenoside Rb1 could maintain cell viability, significantly increased ALP activity, osteogenic and angiogenic genes expression. Meanwhile, micro-nano HAp granules combined with silk were fabricated smoothly and were a delivery carrier for Ginsenoside Rb1. Significantly, Ginsenoside Rb1 loaded on micro-nano HAp/silk could facilitate osteogenesis and angiogenesis. All the outcomes hint that Ginsenoside Rb1 could reinforce the osteogenesis differentiation and angiogenesis factor's expression of BMSCs. Moreover, micro-nano HAp combined with silk could act as a carrier for Ginsenoside Rb1 to repair bone defect.

Status quo and reform proposals of dental doctoral education / 中华医学教育探索杂志

Chinese dental doctoral education has developed multiple lengths of schooling, including eight-year programme, five-year direct doctoral programme, five-year master-doctor combined programme and three-year doctoral programme. The review summarizes the development of the lengths of schooling of Chinese dental doctoral education, compares and analyzes different modes of education and their outcomes. In order to further construct the Chinese dental doctoral education, it’s strongly suggested to set a medical-scientist training programme, to promote the double-track system and to deepen the collaborative reform of medical and educational cooperation to train more outstanding talents for the future development of stomatology in China.

Study of Sr-Ca-Si-based scaffolds for bone regeneration in osteoporotic models / 国际口腔科学杂志·英文版

Bone tissue engineering has emerged as a promising alternative therapy for patients who suffer bone fractures or defects caused by trauma, congenital diseases or tumours. However, the reconstruction of bone defects combined with osteoporosis remains a great challenge for clinicians and researchers. Based on our previous study, Ca-Si-based bioceramics (MSCs) showed enhanced bone formation capabilities under normal conditions, and strontium was demonstrated to be therapeutic in promoting bone quality in osteoporosis patients. Therefore, in the present study, we attempted to enlarge the application range of MSCs with Sr incorporation in an osteoporotic bone regeneration model to evaluate whether Sr could assist in regeneration outcomes. In vitro readout suggested that Sr-incorporated MSC scaffolds could enhance the expression level of osteogenic and angiogenic markers of osteoporotic bone mesenchymal stem cells (OVX BMSCs). Animal experiments showed a larger new bone area; in particular, there was a tendency for blood vessel formation to be enhanced in the Sr-MSC scaffold group, showing its positive osteogenic capacity in bone regeneration. This study systematically illustrated the effective delivery of a low-cost therapeutic Sr agent in an osteoporotic model and provided new insight into the treatment of bone defects in osteoporosis patients.

Recent advances in cell sheet technology for bone and cartilage regeneration: from preparation to application / 国际口腔科学杂志·英文版

Bone defects caused by trauma, tumour resection, infection and congenital deformities, together with articular cartilage defects and cartilage-subchondral bone complex defects caused by trauma and degenerative diseases, remain great challenges for clinicians. Novel strategies utilising cell sheet technology to enhance bone and cartilage regeneration are being developed. The cell sheet technology has shown great clinical potential in regenerative medicine due to its effective preservation of cell-cell connections and extracellular matrix and its scaffold-free nature. This review will first introduce several widely used cell sheet preparation systems, including traditional approaches and recent improvements, as well as their advantages and shortcomings. Recent advances in utilising cell sheet technology to regenerate bone or cartilage defects and bone-cartilage complex defects will be reviewed. The key challenges and future research directions for the application of cell sheet technology in bone and cartilage regeneration will also be discussed.

Biomaterials for bone defect repair and bone regeneration / 中华口腔医学杂志

The treatment of large jaw bone defects remains an urgent clinical problem to be solved. With the development of biomaterials, stem cells and bone tissue engineering, new ideas and hopes for the regeneration of jaw have been offered. In addition to meeting the basic requirements of bone repair materials, scaffolds for the regeneration of large jaw bones require the ability of stem cells to participate in bone regeneration. Methods like optimization of scaffolds composition, design of porous structure and combination of gel and microsphere technology can enhance stem cell delivery in vivo, and the osteogenic differentiation of stem cells can be stimulated through controlled release of drugs, preparation of surface micron/nano topography and modifications of ionic components. Moreover, application of three-dimensional printing and channel structure in large-scale scaffolds fabrication present promising strategies for customized, accurate bone reconstruction and vascularization. It is only through synergistic optimization in all aspects that it is possible to obtain scaffold materials suitable for regeneration of large jaw bones. This article focuses on biological materials regulation, stem cell delivery, survival and differentiation, and their role in bone regeneration.

Application of negative molds technology based on three-dimensional printing in digital maxillofacial prostheses / 中华口腔医学杂志

Objective@#To explore a digital negative molds technique based on three-dimensional (3D) printing to assist in the manufacture of maxillofacial prostheses, and to improve the deficiency of the current clinical treatment.@*Methods@#Seventeen patients with maxillofacial defects (including nasal defects, orbital defects, cheek defects, auricle defect) were scanned by means of facial optical scanning and computer tomography (CT). The 3D models were then reconstructed and global registration was made to merge the reconstructed models into a new digital model for 3D design. The 3D design of the prostheses was implemented in software. The mechanical connection structure was designed by forward engineering technology for 3 patients with intra-oral defects in maxilla who needed to make removable partial dentures, so that the silicone prostheses and removable partial denture could be combined. The removable partial dentures were made by conventional method and connected with the prostheses. According to the 3D data of the prostheses, the digital negative molds were designed, and the 3D printing technology was used to finish the processing of the resin molds. Silicone for prostheses were filled and cured in the resin molds to fabricate the clinical restorations for the patients. The margin adaptation and retention of the prostheses was detected.@*Results@#Twenty patients with varying degrees of maxillofacial defects were rehabilitated using the courses developed in the study. All patients reported no pain or discomfort during the treatment; and they were satisfied with the final prostheses of the shape, color, retention, stability, etc. Eighteen of the prostheses showed good marginal adaptation, and sixteen of the prostheses showed good retention effect.@*Conclusions@#The digital negative molds technique used in this study could greatly reduce the intensity of manual operation and provided a good therapeutic effect for patients with maxillofacial defects.

Establishment of liver IL-6 reporter mouse model by hydrodynamic gene transfection / 军事医学

Objective To construct a mouse model for real-time,noninvasive and specific monitoring of inflammation activation in hepatic tissues.Methods An inflammation reporter gene was targeted to the liver by hydrodynamic gene delivery technology.Bioluminescence imaging was used to detect the firefly luciferase(Fluc) expression in the mouse liver after inflammatory stimulation.Besides,the relevance between the light intensity and inflammation level was also intensively investigated.Results pIL-6-Fluc was successfully delivered to the liver.The hydrodynamic gene delivery could cause a transient liver injury that could return normal in 5 to 7 days.The expression of pIL-6-Fluc could be induced by lipopolysaccharides(LPS) treatment with an about (46.80±13.35) fold increase at the peak value,which was significantly higher than that detected by ELISA [(4.09±0.96)fold].Conclusion An inflammation reporter mouse model is constructed in this study by hydrodynamic gene transfection,allowing noninvasive monitoring of inflammation activation specifically in hepatic tissues.The reporter model is capable of monitoring inflammation activation with a sensitivity higher than that of ELISA.

Changes of the level of phosphorelated ERK1/2 in the spinal trigeminal nucleus of migraine model rats / 中华行为医学与脑科学杂志

Objective To explore the role of ERK1/2 in the central pathogenesis of migraine.Methods Healthy adult male SD rats were randomly divided into five groups:normal group (group C),sham operation group(group C),migraine model group(group M),DMSO group (group D)and PD-98059group (PD group),with 12 rats in each group.The extracellular discharge frequency in the spinal trigeminal nucleus was recorded and ERK1/2 phosphorylation was tested.Results (1) The percentage of extracellular discharge frequency change:Two hours after treatment,the percentage of discharge frequency change was (325.9±47.32)％.The percentage of extracellula discharge frequency change in group M (325.9±47.3)％ was higher than that in group N (100.0± 0.0) ％ and group C(107.3± 16.4)％.There was no significant difference in the percentage of discharge frequency change between group D(319.3±42.5) ％ and group M (325.9±47.3) ％.The percentage of discharge frequency change in group PD(218.5±31.7)％ was lower than that in group M(325.9±47.3)％ and group D(319.3± 42.5)％.(2) ERK1/2 phosphorylation:the ERK1/2 phosphorylation in group M and group D was higher than that in group N and group C.There was no significant difference in ERK1/2 phosphorylation between group D and group M.The ERK1/2 phosphorylation in group PD was lower than the other four groups.Conclusion During the process of central sensitization to migraine,neuronal excitability and ERK1/2 phosphorylation were increased.ERK1/2 inhibitor (PD98059) reduced ERK1/2 phosphorylation and neuronal excitability.These indicated that ERK1/2 may play a role in central sensitization of migraine in rats.

Cytocompatibility of two porous bioactive glass-ceramic in vitro / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To compare the cytocompatibility of two kinds porous bioactive glass-ceramic made by same raw materials.</p><p><b>METHODS</b>Apatite/wollastonite bioactive glass-ceramic (4006) were prepared by sol-gel method, and bioactive glass (45S5) were prepared by melting method. Bone marrow stromal cells (BMSCs) were cultivated, differentiated and proliferated into osteoblasts, from a rabbit's marrow in the differentiatiofn culture medium with active function. The viability of BMSCs cultivated with extraction of these two kinds of biomaterial, which could represent the cytotoxicity effect of 4006 and 45S5 against BMSCs, was evaluated by the MTp assay. BMSCs were seeded and cocultivated with two kinds of biomaterial scaffolds respectively in vitro. The proliferation and biological properties of cells adhered to scaffolds were observed by inverted phase contrast microscope, scanning electron microscope (SEM), and environmental scanning electron microscope (ESEM), and a suitable cell amount for seeding on the scaffold was searched.</p><p><b>RESULTS</b>There was no difference on the viability of BMSCs only cultured for one day by complete extract of 4006 and culture medium (P>0.05), but there was significant difference between them when the cells had been cultured for 3 days(P<0.01). The extract of 45S5 had significantly higher cytotoxicity than extract of culture medium (P<0.01). The BMSCs adhered, spread, and proliferated throughout the pores of the scaffold 4006, and the amount of cells adhered to 4006 was more than to 45S5. The adhered cells to 4006 increased with the rising amount of cells seeded. And 2 x 10(7) cells.mL-1 suspension resulted inthe highest cell adherence during the comparative cells adherence test.</p><p><b>CONCLUSION</b>Apatite/woolastonite bioac tive glass-ceramic has good bioactivity and cytocompatibility. Therefore, it may have the potential to be a new cell vehicle for bone tissue engineering. And the suitable seeding cell amount of apatite/wollastonite bioactive glass-ceramic should be 2x10(7) cells.mL-1 or even more than that.</p>

Experimental study on the levels of related cytokines and behavior changes during the course of fracture healing in streptozotocin-induced diabetic rats / 中华行为医学与脑科学杂志

Objective To investigate the change of levels of related cytokines,including transforming growth factor-β2 (TGF-β2),basic fibroblast growth factor (bFGF),platelet-derived growth factor (PDGF),interleukin-6 (IL-6),interleukin-8 (IL-8) and tumor necrosis factor-α (TNF-α) and behavior in streptozotocin-induced diabetic rats between the before and after fracture,at the same time,to analyse the relativity of them.Methods The rat models of diabetic were induced by intraperitoneal injection of streptozotocin,which were divided into different diabetes mellitus group (DM group) randomly.The right tibiofibula of all the rats of diabetes mellitus group and normal control group(NC group) were broken,and then treated with external fixation.The bone callus formation was evaluated by X-ray.When all the operation above was completed,the rats were domesticated in different cages.The concentration of related cytokines of the DM groups and NC group was detected at different time.Results The behavior changes of diabetes fracture rats were distinct and appeared a series symptoms such as bradykinesia,dull,polydipsia,polyphage,polyuria,emaciated obviously.The concentration of related cytokines (TGFβ2,BFGF,PDGF,IL-6,IL-8 and TNF-α) of the two groups was detected at 1,2 and 4 weeks.The difference between them was significantly(TNF-α:the concentration of NC group were (9.87 ± 1.06) ng/ml,(14.07 ± 1.43)ng/ml and(12.02 ± 1.02) ng/ml; the concentration of DM group were (11.65 ± 1.18) ng/ml,(16.29 ± 1.24)ng/ml and(13.87 ± 1.25)ng/ml ; P ＜ 0.05).X-ray films showed that the fracture healing of NC group was more superior than that of DM group.Conclusion The reduction of TGF-β2,BFGF,PDGF and the increase of IL-6,IL-8,TNF-α in early fracture are one of important reasons for delayed union and nonunion in diabetic rats.At the same time,there is a cooperative action between them.Dynamic observation of the concentration of related cytokines will provide eliable experimental data to estimate fracture healing,delayed union and nonunion.It is favourable to acquaint the regulatory mechanism of fracture healing at molecular level.

Peripheral nerve regeneration using carbon nanotubes enhanced chitosan/collagen composite nerve conduit / 中国组织工程研究

BACKGROUND: Nanotechnology has widely used in tissue engineered reconstruction in recent years. Most reports are concerning carbon nanomaterials in bone reparation, but the study of peripheral nerve regeneration is poorly understood.OBJECTIVE: To improve the physical, chemical and biological properties of chitosan/collagen composite nerve conduit with functionalized carbon nanotubes, in addition, to investigate the therapeutic effect of this novel material.DESIGN, TIME AND SETTING: The same body controlled experiment of animals was performed at the Tissue Engineering Laboratory and The Key Laboratory of Thin Film and Microfabrication Technology, Shanghai Jiao Tong University from February 2005 to November 2006.MATERIALS: The carbon nanotubes were mixed with 2% chitosan solution, coated on the die to prepare chitosan/collagen composite nerve conduit with functionalized carbon nanotubes. The chitosan/collagen tubes were served as controls.METHODS: A total of 80 male adult-rats were prepared a 4 mm accessory nerve defects models, and repaired by nerve conduit in the experimental material and control material groups. In the auto nerve grafts group, the removed nerve was connected to the broken end. In the blank control group, there was no other treatment except removing 2 mm nerves. The left sides were served as experimental sides and the right sides as within-subject controls.MAIN OUTCOME MEASURES: The repairing outcomes were measured by electrophysiological, myophysiological, and histological measurements.RESULTS: The accessory nerve defects were repaired in a rat model using carbon nanotubes in chitosan/collagen-based composite nerve conduit. As time passed after the surgery, good results of the electrophysiological, myophysiological and histological measurements were achieved, which were similar or superior to those of the nerve autografts.CONCLUSION: The carbon nanotubes in chitosan/collagen-based composite can be an ideal candidate for peripheral nerve regeneration.

Test of transient expression of green fluorescent protein gene transferred to bone marrow stromal cells / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To determine the optimized condition under which BMP expression vector will be constructed to transfect bone marrow stromal cells (MSCs), plasmid vector coding enhanced green fluorescence protein (EGFP) gene pEGFP was transferred into MSCs. The transfer efficiency and transient expression were subsequently tested.</p><p><b>METHODS</b>pEGFP plasmid was amplified and tested by an enzyme cutting technique in vitro. MSCs, which were initially obtained from the bone marrow of rabbits, were cultured in vitro and transferred with pEGFP by means of lipofectamine media methods. The ratio of plasmid and lipofectamine was varied according to the experiment design. Transfer efficiency and transient expression were evaluated by fluorescent microscopy.</p><p><b>RESULTS</b>Transfer efficiency was correlated with the ratio of plasmid and lipofectamine. The expression of EGFP began in 24 hours after transferring, reached maximum in 48-72 hours and decreased in 1 week, however there remained a weak expression for more than 3 weeks.</p><p><b>CONCLUSION</b>The efficiency of transferring pEGFP into MSCs could achieve to 30% with proper ratio of plasmid and lipofactamine. pEGFP was an ideal transient expression vector for MSCs gene transference.</p>

Effect of SNP on GFAP synthesis with immunofluorescent method in hippocampus / 中国药理学通报

Aim To observe the effect of sodium nitrop russide (SNP)on glial fibrillary acidic protein(GFAP) synthesis in the gerbil hippocampus. Method lmmunofluorescent histochemical staining method was used. Result SNP increased GFAP synthesis in rediatum layer,molecular layer and dentate gyrus.There were not GFAP positive cells in rediatum layer and mol ecular layer.Number of GFAP positive cells related to dose of SNP.Conclu sion SNP increased GFAP synthesis.

The effect of basic fibroblast growth factor on new bone formation in the repairment of mandibular defects / 实用口腔医学杂志

Objective: To study the effects of basic fibroblast growth factor(bFGF) on promoting new bone formation in repairing mandibular defects.Methods: 15 mm?6 mm bilateral mandibular periosteum bone defects were made surgically in 18 adult New Zealand rabbits, the right defects were repaired with natural non organic bone (NNB) combined with bFGF at 40 ng/mm 3, the left defects were repaired with NNB. Specimens were obtained 3, 6, 12 weeks after operation respectively. The effects were evaluated with toluidine blue stain observation, tetracycline fluorescent microscopic examination and computerized quantity analysis. Results: More chondrocytes were observed in the right defects 3 weeks after operation. 3, 6, 12 weeks after operation the new bone formation (?m 2) in the right defects was 66.092?6.379, 130.198?13.213 and 235.374?16.773 respectively; that in the left defects 21.844? 7.731 , 62.694?10.389 and 160.184?14.793 respectively( P