This article briefly summarized conventional k-space technique, partial k-space sampling and key hole technique, then introduced the latest applications during these years.
Magnetic Resonance Imaging

OBJECTIVETo explore a simple but novel method of strengthening gypsum material by cyanoacrylate infiltration. To evaluate the influence of cyanoacrylate on the mechanical properties of dental gypsum models.

METHODSGypsum specimens were polished to the dimension of 35 mmx4 mmx4 mm. Butyl-cyanoacrylate was diluted with chloroform at different concentrations, namely 20% and 30% cyanoacrylate. Gypsum specimens were infiltrated by diluting one component of cyanoacrylate at different concentrations for 8 h and then dried for analysis. The changes in elastic modulus, fracture toughness, compressive strength, biaxial strength, brinell hardness were measured. The data were analyzed using software OriginPro 8.

RESULTSThe viscosity measurements indicated that diluted cyanoacrylate were Newtonian fluids and the viscosity increased slightly within the 48 hours of preparation but still similar as water at room temperature, which could be used to infiltrating gypsum. The gypsum infiltrated with cyanoacrylate exhibited good physicochemical properties. The biaxial strength, fracture toughness, compressive strength and brinell hardness of the gypsum were improved by 39%, 30%, 63% and 18%, respectively.

CONCLUSIONCyanoacrylate can significantly improve the strength of gypsum model which indicates the potential clinical application.

Objective To study the effects of EP4 and EP2 antagonists on the differentiation of Treg/ Th17 cells and disease progression in mice of collagen-induced arthritis (CIA) model.Methods DBA/1 mice wereimmunized subcutaneously twice at the root of the tail with type Ⅱ collagen emulsified in Freund's complete adjuvant.EP2 and EP4 antagonist therapies were intraperitoneally administrated for 14 consecutive days after the second immunization.Clinical signs,histological manifestation,serum interleukin (IL)-17 and quantity of CD4+CD25+Foxp3+ Treg cells were determined.ANOVA and t-test were used for statistical analysis.Results Clinical signs of the disease appeared on day 27 and peaked on day 35 after the first immunization.The quantity of CD4+CD25+Foxp3+ Treg cells in spleens [(1.67±0.15)％] and draining inguinal lymph nodes [(3.30±0.36)％] isolated from CIA mice were significantly lower than those of normal DBA/1 mice [(2.77±0.45)％ and (4.73 ±0.45)％ respectively,P＜0.05].Serum IL-17 level of CIA mice [(27±7) pg/ml] was significantly higher than that of normal DBA/1 mice [(14±4) pg/ml,P＜0.05].Intra-peritoneal injection of EP4 but not EP2 antagonist to CIA mice decreased paw edema and swelling,and alleviated the histological manifestations (1.8±1.0 vs 3.5±0.6,P＜0.05) on day 35 after the first immunization.The percentages of CD4+CD25+Foxp3+ Treg cells in both inguinal lymph nodes [(4.20±0.32)％] and spleens [(2.63±0.40)％] were significantly higher in EP4 antagonist-treated but not EP2 antagonist-treated CIA mice compared with CIA mice group [(3.30±0.36)％ and (1.67±0.15)％ respectively,P＜0.05].The level of serum IL-17 was significantly lower in EP4 antagonist-treated [(15±7) pg/ml] but not EP2 antagonist-treated CIA mice compared with CIA mice group [(27±7) pg/ml,P＜0.05].Conclusion EP4 antagonist therapy alleviates clinical symptoms of CIA,improves the histological manifestations,decreases the serum IL-17 level and increases the percentages of CD4+CD25+Foxp3+ Treg cells in both spleens and draining inguinal lymph nodes,so targeting EP4 receptor may be a new possible therapeutic possibility in the prevention and treatment of rheumatoid arthritis.

BACKGROUND: It is a key point to revascularize the tissue-engineered bone during the repairing of large bone defect. Fascia flap is commonly used in clinic to accelerate the blood supply of implant.OBJECTIVE: To observe the feasibility of repairing goat tibia defects with tissue-engineered bone and accelerating revascularization with fascia flaps.DESIGN: Randomized and controlled animal experiment SETTING: Department of Traumatic Orthopaedics, Nanfang Hospital,Southern Medical University.MATERIALS: Totally 36 goats with the body mass of 14.5-15.5 kg of either gender were enrolled.METHODS: This experiment was conducted at the Department of Traumatic Orthopaedics, Nanfang Hospital, formerly the First Military Medical University of Chinese PLA from December 1999 and December 2003.Bone and periosteum defects 20 mm long were made and fixed with plate of left tibia in 36 goats. They were randomly divided into four groups: Group A in which the defects were filled with coral hydroxyapatite (CHAP), Group B I CHAP+ bone marrow stroma cells (BMSc); Group C with fascia flaps;Group D with nothing. Next, the bone regeneration and the revasculariza tion were evaluated. Radionuclide bone imaging was done 2, 4, 8 weeks after operation. After X-ray examination, the index of optical density of Xray films and histology of the implants were analyzed at 4, 8, 12 weeks after operation, and the biomechanical characters were studied 12 weeks postoperatively.MAIN OUTCOME MEASURES: Gross observation and X-ray, radionuclide bone imaging, biomechanical and histological observation RESULTS: Totally 36 goats entered the stage of result analysis. ① Gross observation of the repair sample of bone defects of the animals in each group: there was no osteogenesis postoperatively at each time point in the blank control group . In Group B, at week 8 to 12, there was no obvious osteogenesis and callus formation on the surface of the materials. In Group C,At weeks 8 to 12, bone defects were filled gradually, many bone callus processes were seen on the surface of the materials , centralizing and enwrapping the materials. The osteogenetic process in the Group C were superior to that of theGroup B. ②Examination result with -901/SA PET-CT scanners: It was seen by naked eyes that at weeks 2 to 8 in the Group A,the radioactivity concentration at region of interesting (ROI) of the operation side had obvious increasing trend, and similar trend of changing appeared in the Group B and Group C, but the ROI counts and T/NT value in the Group B were both lower than those in the Group C. The decreasing trend in the Group A was lower than that in the Group B. ③) Radiological results: the osteogenesis volume through measuring absorbance in the order from large to small was Group C, Group B, and Group A[At week 12, they were (4.180±0.192), (3.480±0.453), (2.959±0.682)respectively ].④Biomechanical results: there were significant difference of loading and bending stress in the Group C, Group B and Group A [ The loading was (758.333±88.754), (530.214±65.297), (359.667±60.715)N , respectively; and the bending stress was (13.937±2.199), (10.123±1.243),(6.223±0.945)N/mm2, respectively ].⑤)Histological results: Slices at various time points in the blank control group showed no bone tissue. In the other three 3 groups, with the prolongation of time, the osteagenetic range and quality were in the order of Group C, Group B and Group A.CONCLUSION: The fascia flaps can accelerate the revascularization process in the formation of tissue-engineered bone so that the capability of tissue engineered bone to repair the large bone defects may be enhanced.

BACKGROUND: The main aspect of the study in the bone histological engineering is how to maintain and improve theosteogenesis of the osteoblasts in vivo and in vitro. The gene transference may provide a new effective method to deal with theproblem.OBJECTIVE: To discuss the effect of the reverse transcription virus mediated human bone morphogenetic protein7(hBMP-7) gene transfection on the proliferation and osteogenetic differentiation of the bone marrow mesenehymal stemcells (BMSCs) of the rabbits.DESIGN:Cells taken as the study object, grouping control, repeat observation andmeasurement.SETTING: Traumatological and othopaedic lab of a medical university hospital.PARTICIPANTS: The study wascompleted in the Traumatological and Othopaedic Lab in the Affiliated Nanfang Hospital of the Southern Medical University from July 2001 to July 2003. Four New Zealand rabbits,whose weights varied from 1.0 to 1.5 kg, were provided without sexlimit by the Animal Experiment Center of the First Military Medical University of Chinese PLA.METHODS:The reverse transcription virus carriersof the hBMP-7 were constructed,and then the BMSCs were transfected by the virus containing target genes. The expression of the hBMP-7 protein was detected with the immunohistochemical method. The cell proliferation, cycle and ALP synthesis were respectively detected with the MTT method,flow cytometer and NPP method.MAIN OUTCOME MEASURES: Primary results: ① the detection results of the cell proliferation. ② the detection results of the ALP.Secondary results: ① the expression of the hBMP-7 protein in the transfected BMSCs. ② the detection results of the cell cycle.RESULTS: After the BMP-7 gene transfection, there was hBMP-7 positive expression in the BMSCs of the rabbits,using the immunohistochemical detection. There was no significant change in the BMSCs proliferation of the rabbits after the hBMP-7 gene transfection ( P ＞ 0.05). Compared with the ALP synthesis of the transfected BMSCs(294. 592 ± 86. 567) nkat/L, there was significant difference in the ALP synthesis of the empty carrier transfected BMSCs(155. 231 ±86.567) nkat/L and the un-transfected BMSCs (160. 866 ±91. 585)nkat/L( F =5. 660, P ＜ 0. 05).CONCLUSION: After the BMP-7 gene transfection, the BMSCs can synthesize and express the extragenous BMP-7. The hBMP gene transfection can promote the differentiation of the BMSCs cultured in vitro into the osteoblasts and can be used as the seed cells in the construction of the histological en gineering bone tissues and in further application.

Objective To study the receptors signaling of prostaglandin E2 on the differentiation of regulatory T (Treg) cells and Th17 cells.Methods The expression of prostaglandin E2 receptors (EP1/EP2/EP3/EP4) on the MACS-purified CD4+CD62L+ T (Th0) cells was analyzed by flow cytometry and reverse transcription polymerase chain reaction (RT-PCR).The quantity of CD25+Foxp3+ cells was examined by flow cytometry,the expression of FoxP3 mRNA and RORγt mRNA were detected using real-time RT-PCR,the level of IL-17 in the culture supernatants was detected by enzyme-linked immunosorbent assay (ELISA).ANOVA,LSD-t,Dunnett T3 were used for statistical analysis.Results EP1,EP2,EP3,EP4 were expressed on Th0 cells at different levels,and EP2 [(89.7±9.1)％] had the strongest expression.PGE2 [(3.0± 2.2) ％],EP2 agonist [(4.5± 1.0) ％] and EP4 agonist [(8.8 ±2.5) ％] decreased the quantity of CD25 +Foxp3 + cells compared with the control group [(28.6±6.8)％] (t=7.156,P=0.021; t=6.958,P=0.032; t=5.359,P=0.044).PGE2(0.210±0.020),EP1 agonist (0.833±0.045),EP2 agonist (0.227±0.025) and EP4 agonist (0.450±0.060) decreased the expression of Foxp3 mRNA compared with the control group (1.000) (t=23.817,t=5.026,t=23.313,t=16.581; all P=0.000).PGE2 [(22±6)pg/ml],EP2 agonist [(24±5)pg/ml]and EP4 agonist [(207±19) pg/ml] decreased the secretion of IL-17 compared with the control group [(678±87) pg/ml] (t=14.925,P=0.004; t=14.873,P=0.004; t=10.480,P=0.008).PGE2 (0.141±0.027),EP1 agonist (0.869±0.033),EP2 agonist (0.176±0.029) and EP4 agonist(0.371±0.042) decreased the expression of RORγt mRNA compared with the control group (1.000) (t=34.046,t=5.184,t=32.673,t=24.962,all P=0.000).Conclusion EP1,EP2,EP3,EP4 receptors are expressed on CD4+CD62L+ T (Th0) cells at different levels.Prostaglandin E2 inhibits the differentiation of Treg cells and Th17 cells via the EP2 and EP4 receptors signaling.

Objective To investigate the variations of intestinal flora of common carp in patients with hyperuricemia in Qingdao District.Methods The fecal flora was analyzed by gradient dilution method.The levels of uric acid in blood and feces were detected by enzyme colorimetry method and phosphortungstic acid method,respectively.Results E.coli (7.58 ± 0.34,P ＜ 0.05),the total count of aerobian (7.76 ± 0.67,P ＜ 0.05),and bacteroides (2.75 ± 0.31,P ＜ 0.05) were significantly increased in hyperuricemia patients compared to controls.Bifidobacterium (5.38 ± 0.34,P ＜ 0.05) and lactobacillus (2.69 ± 1.48,P ＜ 0.05) were sig-nificantly decreased compared to controls.Concentrations of uric acid in blood and feces were both significantly higher in the patients relative to healthy controls.Decomposition capability was similar to healthy controls.Decomposition capability of uric acid revealed a close correlation with bifidobacterium and lactobacillus,respectively (r =0.565,0.328,P ＜ 0.05).Conclusions Intestinal dysbacteriosis was found by the analysis of fecal flora in patient with hyperuricemia in Qingdao district.Dysbacteriosis might participate in the process of hyperuricemia onset.

Objective To establish three dimensional finite element model libraries of telescopic dentures and removable partial dentures by means of model libraries, and compare the characteristics of stress distribution among three prostheses. Methods Normal model libraries were imported and edited, and models of bilateral free-ended cases were established. Based on the model libraries of fixed partial dentures and removable partial dentures, the finite element models of telescopic dentures and removable partial dentures with medial or distal occlusal rest were established using softwares such as DELL Precision Graphics Workstation, UG 5.0, HyperMesh 7.0 and Abaqus 6.5, then finite element stress analysis was performed. Results The stress distribution on abutment root, parodontium, alveolar mucosa and alveolar bone was uniform. The maximum value of stress on the abutment root (6.205 Mpa) was much less than those of two removable partial dentures (18.41 Mpa and 34.49 Mpa). Conclusion For bilateral free-ended cases, the telescopic denture design is uniform in stress distribution with less stress on abutment root, which is healthy to the abutment root and surrounding tissues.

Objective To redevelop the finite element model libraries and to analyse the stress distribution of telescopic crown dentures. Methods The finite element model libraries were redeveloped based on the model libraries of normal dentition, fixed partial denture and removable partial denture. With the help of softwares such as DELL Precision Graphics Workstation, UG 5.0, HyperMesh 7.0 and Abaqus 6.5, the telescopic denture models on the bilateral free-ended case were imported and edited, then the finite element stress analysis was performed. Results The models were easily established. The maximum value of stress and its distribution on abutment root, periodontal membrane, alveolar mucosa, alveolar bone and dental prostheses were observed and studied by the finite element stress analysis. Conclusion The way to establish models of telescopic crown dentures by model libraries is feasible and reliable.

Irritable bowel syndrome (IBS)is a commonly seen digestive system disease,and its pathogenesis is not fully clarified.The treatment of IBS includes change of life style and diet habit,medicine and psychotherapy,yet the therapeutic efficacy is not satisfactory.Studies have shown that peppermint oil is an effective drug for IBS,which can ameliorate symptoms of IBS and raise the patients'quality of life.This article reviewed the advances in basic science and clinical studies on peppermint oil in treatment of IBS.