Most medical postgraduates desire to develop their research mentality and experiment skills and become capable medical students with potentialities and innovation consciousness.Medical postgraduates can be classified into academic, general, and clinical types based on their needs, education background, experiences and personal abilities, while their supervisors fall into high-, medium-, and low-expectation types according to their research abilities and demands.Cross-pairing analysis shows that a high-level cooperation can be achieved when the type of a postgraduate matches that of his supervisor, otherwise a low-level cooperation may result.Therefore, it is essential to optimize the two-way choice system between postgraduates and supervisors, establish a moral code for supervisors and academic standards for postgraduates, and further enhance their interaction.A new relationship should be formed between medical postgraduates and supervisors, which is postgraduate-centered, emphatic on conversation, discussion, equality, and mutual trust and respect, and capable of promoting the harmonious development of academic activities.

Presently,studies of onset,development and tumor drug resistance of osteosarcoma were few.Further studies on tumor animal models can provide a promising basis for treating osteosarcoma.Commonly used animal models of osteosarcoma include mouse,rat,rabbit and dog.Organs of rats are similar to human,so does genotype.Dogs can spontaneously develop osteosarcoma,which is similar to human,and are frequently used as spontaneous tumor models.However,there are some differences in biological features,pathogenic mechanism and histology.With the development of studying,there will be more and more new animal models in accordance with human osteosarcoma characteristics.The present study served to review methods of establishing models,characteristics and detailed application of animal models of osteosarcoma.

It has been a novel clinical way to repair damaged articular cartilage with autologous chondrocytes cultured in vitro using cartilage tissue engineering technique. There have been many articles about the techniques of chondrocytes culture in recent years. After summarizing and analyzing the involved articles,factors on chondrocytes cultured in vitro were reviewed,including dimension,stress,cell density and oxygen tension,etc. Chondrocytes cultured in three-dimensional with multi-factors in vitro can promote quality and quantity of cartilage in tissue engineering. But factors on chondrocytes culture are so complicated that further researches will be needed.

Various kinds of scaffold materials are studied and used in cartilage tissue engineering, but none are ideal for the needs of tissue engineering. Mixing different materials together to form a better composite scaffold may brighten the prospect. The present review summarizes the studies of composite materials in cartilage tissue engineering.

Joint prosthesis is one of the most successful procedures in orthopaedic surgery and has considerably improved the quality of life for patients affected by terminal joint disease. However,a number of joint prosthesis ultimately failed because of aseptic loosening. There have been major advances in the understanding of aseptic loosening. The RANKL-RANK-OPG-NF-?B system has been shown to play a fundamental role in aseptic loosening. We review how the RANKL-RANK-OPG-NF-?B system regulates aseptic loosening and aseptic loosening drug intervention.

Adipose-derived stem cells(ADSC) can be easily obtained in large quantities and with minimal discomfort.As seed-cells,ADSCs may be well suited to tissue engineering and regenerative medical applications.This article presents an overview of the isolation,expansion,characterization,differentiation and application prospects of ADSCs,as well as the existing challenges in their studies,in an attempt to promote their clinical applications.

Leptin may indirectly suppress bone formation via a central nervous relay and may stimulate bone formation via direct peripheral effect. Leptin' s antiosteogenic function is mediated through the sympathetic nervous system and does not involve pathways with melanocortin and cocaime-amphetamine-regu-lated transcript, which are critical for leptin' s anorexigenic action. Leptin' s actions to modulate bone formation through sympathetic nervous system could suggest new therapeutic approaches for diseases such as osteoporosis. The progress of the relationship between leptin and sympathetic nervous system and bone formation is reviewed.

Osteogenic protein-1(OP-1),also referred to as bone morphogenetic protein-7(BMP-7),has the effective osteoinduction.In reconstructive surgery of the hip,OP-1 could induce greater and earlier new bone formation,accelerate the incorporation of the graft and host-bone,and enfance the fixation of the plant.The characteristics in the molecular biology and it's application in reconstructive surgery of the hip was reviewed.

Damaged articular cartilage has a limited intrinsic capacity to heal itself,especially in adults,It represents a clinical challenge.Novel gene therapy can introduce particular beneficial gene into the seeded sells and express growth factors or other therapy proteins at the repair site.Gene therapy focuses on selecting proper gene,target cells and the transferring systems. The tissue engineering cartilage with gene-modified seeding cells and transferring objective gene to target sells locally present new therapeutic regimens for repairing defects in articular cartilage.

The hallmark of osteoarthnitis(OA) is the loss of articular cartilage caused by an imbalance between cartilage synthesis and degredation over a variable period of time.IL-1 plays an important role in the course.The IL-1receptor antagonist(IL-Ra) specific against IL-1 is becoming a pivot of wide attention.The article offers a review of the relationship between the IL-1Ra and OA.