Following the basic theory of protecting gas-reservoirs from damage with the temporary bridging technology, inert calcium carbonate (CaCO3) particles, whose diameter is consistent with the size of pores or apertures in the reservoir, were selected as the bridging agent, and modified resolvable starch was selected as filtration loss reducing particles to form the non-clay low damage temporary bridging drilling/completion fluids system (NLTDFS). Under the simulated condition of the well bottom during real drilling, NLTDFS was used to conduct dynamic and static damage experiments of cores for 48 hours, respectively, and then the experimented cores were permeated with pure nitrogen from the undamaged end to the damaged one to measure their recovery of permeability. The results showed that the permeability recovery rate of the core reached 90% or so, and the damaged depth was less than 1 cm, which demonstrates that NL TDFS has higher temporary bridging effectiveness and lower damage to the gas-reservoir than other drilling fluids system. NLTDFS has been used to drill many horizontal wells, and four of them have obtained high yield of natural gas. The yield of natural gas of LPl well reached 85 X 104 m3/day after completion with the rump pipe. The formation of the stable well wall and smooth drilling led to an API loss less than 4 mL and an HTHP loss less than 15 mL.

Accidents, Occupational ; Humans ; Hydrogen Sulfide ; poisoning

Objective To assess the radiofrequency ablation (RFA) lesions in canine prostate with real-time harmonic gray-scale contrast-enhanced ultrasonography and investigate the feasibility to predict these lesions.Methods A total of 5 male beagle dogs took RFA of the prostate.Radiofrequency (RF) was delivered under transrectal ultrasound (TRUS) guidance.A lesion was created in the right and left lateral lobes of canine prostate,respectively.The examination of conventional gray-scale ultrasonography,power Doppler ultrasonography,real-time harmonic gray-scale contrast-enhanced ultrasonography were performed immediately after RF procedure.All animals were subsequently sacrificed and the prostates were harvested for pathologic analysis.Thermal lesion volume was calculated based on expected shape of ellipsoid using equation.The volumes of the calculated thermal lesion on contrast-enhanced ultrasonography in dogs were compared with the volumes obtained from the pathological specimens.Results The RFA lesions could not be imaged accurately with real-time conventional gray-scale or power Doppler ultrasonography.However,contrast-enhanced low MI perfusion imaging was able to have real-time monitoring for the lesion (no blood flow).The volume of lesions was measured with contrast-enhanced ultrasonography without significant difference with those of pathologic results.Ultrasonic imaging(conventional gray-scale or power Doppler sonography)of the ablation areas also had its own characteristics.Conclusion The real-time harmonic gray-scale contrast-enhanced ultrasonography appears to be an accurate modality for assessment of RFA lesions.Conventional gray-scale and power Doppler sonography had their own characteristics to evaluate the RFA lesion.

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.

Objective To explore the dynamic changes of endothelial barrier antigen (EBA) and vascular endothelial growth factor (VEGF) expressions in cerebral cortex under the condition of blood-brain barrier damage in rats following radi?ation-induced brain injury, which provided clinical references. Methods Forty-eight clean grade male SD rats were divid?ed into the control group and 7 d, 14 d, 28 d after brain irradiation group (n=12 for each group) by using stochastic indicator method. The radiation-induced brain injury model was established by using electronic computer X-ray tomography tech?nique. The 3%Evans blue (EB) was injected into rats according to the dose of 3 mL/kg via the tail vein, then the blood ves?sels of cerebral cortex were exposed after having a craniotomy. EB extravasation was detected by microcirculation micro?scope. The permeability of blood-brain barrier was evaluated by using microscope vascular camera device. The expressions of EBA and VEGF in the cerebral cortex were measured by immunohistochemistry staining in each group. Results Both of EB extravasation and VEGF expression in rat cerebral cortex were significantly increased in injury group at day 7, 14 and 28 after brain irradiation compared with those of control group (P<0.05), and which were gradually decreased from day 7 to day 28 after brain irradiation. There were significant differences in EB extravasation and VEGF expression between the injury subgroups (P<0.05). There was a positive correlation between EB extravasation and VEGF expression (r=0.898, P<0.001). The expression levels of EBA were decreased at different time points in injury groups compared with those of control group (P<0.05), and gradually increased from day 7 to 28 after injury. There were significant differences in expression levels of EBA between injury subgroups (P<0.05). The expression of EBA was negatively correlated with EB extravasation (r=-0.866, P<0.001). Conclusion The increases of blood-brain barrier permeability have important relation to the decreases of EBA expression and the increases of VEGF expression after radiation-induced brain injury.

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 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.

Objective To study the effect of 17-β estradiol on Collagen Ⅰ,lysyl oxidase like 1 (LOXL1),fibrinectin( FN )after stretch in the pelvic function dysfunction(PFD) patients vaginal wall fibroblasts cultured in vitro,and the effect in PFD pathogenesis.Methods Twelve patients with pelvic function dysfunction who under surgery in the second Hospital,Hebei Medical University from October 2009 to September 2010 were collected vaginal wall organization in this study.Use of tissue and collagenase digestion method for primary culture in the vaginal wall fibroblasts.After stretch with different concentrations of 17-β estradiol cultured fibroblasts.Total mRNA was extracted from fibroblasts and gene expression of Col Ⅰ,LOXL1,FN were measured.Results After stretch,the expression of Col Ⅰ ( 1.1872 ± 0.0733 vs 1.5035 ±0.0733,t =-4.815,P ＜0.01),LOXLI(0.7724 ±0.1873 vs 1.0855 ±0.0805,t =-5.111,P ＜0.01 ) were significant higher than before( P ＜0.01 ),the expression of FN (0.4290 ±0.1168 vs 0.4215±0.0830) was not significantly different ( P ＞0.05).The expression of all factor Col [ (3.0809 ±0.1862),LOXLI ( 1.5863 ±0.3241 ),FN( 1.1418 ± 1.0030) in high drug concentrations of 17-β estradiol were increased significant compared with controlled groups( P ＜ 0.01 ).Conclusions 17-β estradiol increased synthesis of extracellular matrix components from cultured vaginal wall fibroblasts of patient with pelvic floor dysfunction after stretch.Stretch and estrogen may play an important role in PFD pathogenesis.