BACKGROUND:As a lightweight metal with mechanical properties similar to natural bone, a natural ionic presence with significant functional roles in biological systems, and in vivo degradation via corrosion in the electrolytic environment of the body, magnesium (Mg)-based implants have the potential to serve as biocompatible, osteoconductive, degradable implants for load-bearing applications. On the other hand, Mg, as a critical mediator of cellular growth and activities regulation, is the second most abundant intracellular cation where it plays an important role in enzyme function and trans-membrane ion transport.
OBJECTIVE:To retrospectively summarize the application progress, physiological role and mechanism of Mg, and to review its regulation of bone metabolism.
METHODS:Papers addressing application, physiological and bone metabolism regulation of Mg published in core periodicals were reviewed. Studies in which Mg were used as an assistance materials, or articles regarding cellphysiology in which Mg were not the main research object were excluded. Literatures concerning the regulation of bone turnover by Mg were given special attention.
RESULTS AND CONCLUSION:Mg al oys are cytocompatible materials with adjustable mechanical and corrosion properties and show their potential as biodegradable implant materials. Moreover, Mg is abundantly distributed among the body and essential for maintaining physiological function of the cells. Mg deficiency has been associated with a number of clinical disorders including osteoporosis. But it remains to be determined what specific biochemical process is activated by Mg2+to regulate cellular activity and bone turnover. Further investigations of the precise mechanism are valuable to the clinical application of Mg.

BACKGROUND: The femoral neck fracture is a common skeletal injury, with high mortality and disability rate. Nonunion and avascular necrosis in femoral head are the main problems in treatment of femoral neck fracture. Up to now, the guidelines for its management continue to be unsolved and are stil evolving.
OBJECTIVE:This study aims to summarize the incidence of two femoral neck fracture complications, as wel as the advance in prevention and treatment. This work can help to better understand the mechanism of non-union and avascular necrosis, and to choose the optimal management of this fracture.
METHODS:Papers in terms of femoral neck fracture published in core periodicals were reviewed. Studies which are not directly related to femoral neck fracture or articles regarding poly-trauma were excluded. Literatures concerning non-union and avascular necrosis after femoral neck fracture were preferred.
RESULTS AND CONCLUSION:A total of 241 articles were screened out, and those were mainly published in the last five to ten years. 182 unrelated papers were excluded, and 59 papers were included in the analysis. The femoral neck fracture has a high incidence. Nowadays, there are a variety of treatments for this fracture, but the stability and healing result of fractures depend on many factors, such as age, classification of fracture, general condition of patient, and accompanying diseases. Up to now, the choice of management is stil controversial. Imaging representation and patient’s age are not the main factors for the selection of treatment. Hence, a comprehensive assessment of the risk factors that influence fracture healing is necessary for surgeons to choose an optimal treatment of this fracture. Femoral neck fractures, therefore, represent an enormous socio-economic and medical problem and chal enge surgeons to find the cheapest and most effective way to treat them. Internal fixation of the fracture in combination with the use of osteo-inductive materials may be a new way to further improve the treatment effects of femoral neck fracture.

The concept of "three-yin and three-yang" in Shanghan Lun (Treatise on Cold Pathogenic Diseases), a classic written by Zhang Zhongjing in Han Dynasty, has been always the focus of dispute in successive dynasties. The essence of "three-yin and three-yang" has not been fully revealed up till now. Through studying the six divisions of day and night, the six diseases, the combination of syndromes, the complicated diseases, the complete recovery time and the space division of "three-yin and three-yang", the authors draw a conclusion that the "three-yin and three-yang" in Shanghan Lun is a concept of time-sequence, which is associated with the location of disease in space. So it is suggested that the "six diseases" in Shanghan Lun is a categorization for exogenous febrile diseases, and this categorization reveals a sort of inner relationship between the emergence, development, transformation of the febrile diseases and the time.

BACKGROUND:The main factors that influence revision of acetabular bone defects include evaluation of acetabular bone defects,reconstruction of acetabulum and appropriate acetabular cups used in revision.OBJECTIVE:The review from the three aspects will help to choose an appropriate cup in revision and to formulate the best revision protocols.METHODS:A computer-based online search of PubMed was performed for English articles published from January 1900 to June 2009 with the key words of acetabulum,revision,bone defect,in English and Chinese.Clinical studies published in core periodicals of the latest twenty years were reviewed.Articles regarding primary joint replacement,femoral prosthesis revision and animal experiments were excluded.RESULTS AND CONCLUSION:A total of 61 articles were analyzed,31 were excluded,and 30 mainly published in 5 years,were included.Reconstruction of acetabular bone structure,restoration of original rotation center of hip joint are key factors for repair.Moreover,appropriate prosthesis further benefits the repair effect.Bone transplantation for bone defect and cementedless prosthesis have become favorable methods for revision of acetabular bone defects.

Objective To understand morphological characteristics of sinoatrial node cells(SNCs) by taking purified isolation and culture of neonatal rat's SNCs in vitro and to understand the expression characteristics of surface antigens hyperpolarization activated cyclic nucleotide gated cation channel 4(HCN4) and connexin 45(Cx45) on SNCs.Methods The SNCs were isolated from sinus node tissues removed from neonatal rats by trypsin and purified cultured with differential attachment and 5'-bromodeoxyuridine(BrdU) treatment.Results Three different types of cells were observed among the purified cultured SNCs: spindle,triangular and irregular cells.The spindle cells took up the greatest proportion,had the fastest beats,and had less developed organelle and scarce muscular fibrils.Immunofluorescence staining was positive against HCN4 and Cx45 on the spindle cells.Small amounts of HCN4 was observed on triangular cells.Conclusion ① Isolation by trypsin combined with differential attachment and BrdU treatment is a reliable approach to culturing sinoatrial node cells.② The spindle cells with the fastest beats and positive expressions of HCN4 and Cx45 may be the sinus node pacemaker cells.

AIM: To investigate the effects of losartan on myocardial fibrosis and left ventricular hypertrophy in hypertensive patients. METHODS: 35 essential hypertensive patients with left ventricular hypertrophy were treated with losartan 50-100 mg for 6 mon. Before and after the treatment, serum procollagen typeⅢ (PCⅢ), laminin (LN), and hyaluronic acid (HA) were measured by radioimmunoassay; and left ventricular mass index (LVMI) was determined with ultrasonic cardiogram. RESULTS: After treatment with losartan: the serum levels of PCⅢ, LN, HA, and LVMI were all decreased (P

Objective To evaluate the therapeutic effect and toxicities of low dose Gemcitabine combined with Oxaliplatin in the treatment of advanced or metastatic uroedthelial carcinoma.Methods A total of 42 patients pathologically confirmed advanced or metastatic urothelial carcinoma (23 bladder cancer cases,11 ureteral carcinoma cases,and 8 renal pelvic carcinoma cases) were reviewed.Karnofsky score for each patient before treatment was more than 60.Combined treatment with Gemcitabine and Oxaliplatin regimen was as follows:Gemcitabine 700 mg/m2,iv infusion at day 1,8 and day 15,Oxaliplatin 100 mg/m2,iv infusion at day 2.The regimen was administered for more than 2 cycles (every 4 weeks) and the response rate was evaluated.The regimen was used in palliative chemotherapy and adjuvant chemotherapy,respectively.Results According to WHO evaluation criteria on therapeutic effectiveness,7 patients (16.7％) had complete response,13 patients (30.9％) had partial response,14 cases (33.3％) remained stable status,and 8 cases (19.1％) had progression.The overall response rate was 47.6％.The main side effects included thrombocytopenia,leucopenia,nausea,vomiting and alopecia,which were mild to moderate and disappeared when the chemotherapy was ceased.No chemotherapy related death occurred.Conclusions Combined treatment with low dose Gemcitabine and Oxaliplatin is effective for advanced or metastatic urothelial carcinoma,with mild and tolerable toxicities.

BACKGROUND:Alternative implants affect stability of prostheses,and freeze-dried bone allografts are most selected as implants.The crack between grafts and host bone is unavoidable,which would weaken the bone integration.Bone cement can fill the cracks quickly and completely,however,the effects of bone cement on the stress of prostheses and its own remains poorly understood.OBJECTIVE:To evaluate the effect of the different grafting for bone loss in the presence of the new acetabular component with wings at the time of acetabular revision.METHODS:The finite-element models of acetabular component with three wings and acetabulum with bone loss were established.Following prostheses implantation,the gaps were filled with bone cement and freeze-dried bone allograft,respectively,stress of the graft and its effect on prostheses were analyzed under 2 158 N and 426 N acetabular loads.RESULTS AND CONCLUSION:The finite-element analysis demonstrated that stress and strain at the interfaces of bone-shell and metal-polyethylene liner had the same direction of change but no significant difference between them.In the study,the result indicated increased contact stresses with an increased hip force and orientation.The stress of wings increased gradually from rim to root.Its peak stress was at the joint between the wing and the shell.The different grafts did not affect the stress of the acetabular component.But the stress of bone cement was significantly higher than that of particulate bone.The study demonstrated that change of the graft could not make remarkable effect on the stress of the acetabular component.But the stress of bone cement increased significantly.The result of the finite-element analysis indicated that particulate bone graft is benefit to improving itsstability and to minimize aseptic loosening rate of acetabular component.

Alternative designs have been explored in an attempt to improve the longevity of acetabular prostheses in revision surgery. Many studies had been designed to test the result of the extra-large uncemented hemispherical acetabular components used for acetabular revision in the presence of bone loss. A clinical study of a new acetabular component consisting of a porous metal shell with three wings and an all-polyethylene liner had attained a satisfying result. The purpose of this study was to evaluate the new acetabular component by comparison with the hemispherical acetabular component. The finite-element models of the two acetabular components and the acetabulum in the presence of bone loss were established to calculate the interface stresses during a normal gait cycle with use of the finite-element formulations. Results of the finite-element analysis demonstrated that stress and strain of the two acetabular components had the same direction of change, but the new component had higher stress at the root of wings. In the study, the result indicated reduced contact stresses with a reduced abduction angle of wings. The stress was lower in the new acetabular component of 15° angle of wings compared with the new acetabularcomponent of 30°of wings and hemispherical acetabular component (P < 0.05). The stress of acetabular component with wings showed no remarkable difference by comparison with the extra-large uncemented hemispherical acetabular component. Reducing abduction angle of wings seemed to be a viable means of reducing the stress of the acetabular component while improving its stability.

BACKGROUND: It is conceivable that bone marrow stem cells can differentiate into smooth muscle cells (SMCs) and contribute to neointimal formation in atherogenesis. However, the mechanism remains unknown. The "milieu-induced-differentiation" hypothesis focuses on the key role of cell-to-cell contact and cytokine on the differentiation of stem cells. Bone marrow mesenchymal stem cells (MSCs) have the potential to differentiate into SMCs.OBJECTIVE: To induce MSCs into SMCs in vitro, and investigate the influence of the differentiated SMCs or cell factors on MSCs differentiation.DESIGN: Controlled experiment in vitro with repeated observation and measurement based on cells.SETTING: Department of Cardiology, First Hospital of Xi'an Jiaotong University.MATERIALS: The experiment was accomplished in the Laboratory of Cardiology, First Hospital of Xi'an Jiaotong University between May 2003 and May 2004. SD rats of either gender were provided by the Animal Center of Xi'an Jiao Tong University, 60-80 g, 90-110 g. The following antibodies were used: Mouse anti human SM-α-actin (NeoMarkers),Mouse anti human Calponin (NeoMarkers), TRITC-coupled goat anti mouse IgG antibody (SBA). Mouse anti rat CD34 conjugated FITC (Santa Cruz), Mouse anti rat CD71 conjugated FITC (Oxford Biotechnology), Mouse anti rat anti-CD90 conjugated PE (Oxford Biotechnology). Lipofectamine 2000 (Invitrogen). PEGFP-N3 (the laboratory).METHODS: Bone marrow mesenchymal stem cells were obtained from rat bone marrow by using percoll density gradient centrifugation. SMCs were isolated by using tissue explantation method. Flow cytometer was used to detect the immunofluorescence stain. Then MSCs and SMCs were identified. MSCs were transfected with pEGFP-N3 by Lipofectamine 2000, while untransfected MSCs were taken as controls. Conditioned culture of MSCs and SMCs: ①MSCs at passage 3 were seeded on chamber slides in a 12-well culture plate. The medium was DMEM containing 0%, 5%,7.5% fetal bovine serum (FBS) and SMCs conditioned medium containing 0%, 5%, 7.5% FBS, respectively. The cells were cultured for 10-14 days and immunofluorescence analysis was performed by using monoclonal antibodies against SM-α-actin, calponin.②Indirect co-culture of MSCs with SMCs were established using a semi-permeable membrane cell culture insert. The inserts were plated into culture well. SMCs were cultured on the inside of inserts while MSCs were added to the outside of inserts, respectively. MSCs were culture alone in medium containing 3%, 7.5% FBS and immunofluorescence analysis was performed by using monoclonal antibodies against SM-α-actin, calponin.③MSCs were transfected with pEGFP-N3. After 24 hours, the MSCs were cocultivated with SMCs at an equal density for 7-14 days.As a control, MSCs were cultured alone. MSCs co-cultured were stained with antibodies against calponin, SM-α-actin. MAIN OUTCOME MEASURES: ①Identification of MSCs by floe cytometer.②cytoplasmic antigen expression of SMCs. RESULTS: ①Immunofluorescence analysis showed that MSCs expressed SM-α-actin, but did not express calponin. As a control, SMCs expressed both SM-α-actin and calponin.②Flow cytometry showed that MSCs expressed CD71 of low level, CD90 of high level and no expression of CD34. ③The MSCs transfected with green fluorescence protein continued to express for 2-3 weeks. ④MSCs grew well in SMCs conditioned medium or different concentrations of FBS. Cell growth was FBS concentration dependent in indirect co-culture system of MSCs and SMCs. Several double-positive cells in direct co-culture system were detected enhanced green fluorescence protein and antibodies against calponin, SM-α-actin. CONCLUSION: ①SMCs conditioned medium and cell factor only promote MSCs growth and cytoplasmic granules increase. But these do not induce MSCs differentiate into SMCs. ②The cell-to-cell contact is essential for MSCs differentiation to SMCs.