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Objective To investigate the prevalence rate of non-obese fatty liver disease and its influencing factors, and to provide a reference for the prevention and treatment of fatty liver disease. Methods A total of 23 545 individuals who underwent physical examination in Karamay Central Hospital from January to December 2015 and had complete data of abdominal ultrasound, body mass index (BMI), age, and sex were screened out to analyze the prevalence rate of fatty liver disease, and 7484 individuals with normal BMI who had complete data of triglyceride (TG), fasting blood glucose, and alanine aminotransferase (ALT) were further screened out to perform a multivariate analysis. The t -test was used for comparison of normally distributed continuous data between two groups, and the Mann-Whitney U test was used for comparison of non-normally distributed continuous data between two groups; the chi-square test was used for comparison of categorical data between groups. A multivariate logistic regression analysis was performed to investigate independent influencing factors for non-obese fatty liver disease. Results In 2015, the prevalence rate of fatty liver disease was 30.2% (7116/23 545) among the individuals who underwent physical examination in Karamay Central Hospital. A stratified analysis based on BMI showed that the individuals with emaciation, normal BMI, overweight, and obesity had a prevalence rate of 0.8% (6/706), 9.3% (919/9899), 38.4% (3404/8870), and 68.5% (2787/4070), respectively (all P 0.05), while both of them had a significantly higher prevalence rate than the young individuals (14.5%/16.8% vs 6.0%, P < 0.05). Young and middle-aged male individuals had a significantly higher prevalence rate of fatty liver disease than their female counterparts ( χ 2 =99.40 and 43.29, both P < 0.001), while the elderly male individuals had a significantly lower prevalence rate than their female counterparts ( χ 2 =9.81, P =0.002). For the individuals with normal BMI, the individuals with normal TG had a prevalence rate of fatty liver disease of 5.0% (311/6273), while those with elevated TG had a prevalence rate of 26.8% (325/1211), with a significant difference between the two groups ( χ 2 =624.90, P < 0.001). The multivariate logistic regression analysis showed that age, BMI, ALT, fasting blood glucose, TG, and serum uric acid level were independent influencing factors for fatty liver disease in individuals with normal BMI (all P < 0.001). Conclusion There is a relatively high prevalence rate of non-obese fatty liver disease among individuals undergoing physical examination in Karamay Central Hospital, and 61.5% of the patients with non-obese fatty liver disease have glucose or lipid metabolic disorders. Serum TG level may be used as a simple and effective screening index for non-obese fatty liver disease.
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Objective:To prepare a progressive gradient-aperture scaffold composed of silk fibroin(SF)-chitosan(CS)-nano-hydroxyapatite(nHAp)for osteochondral repair.Method:The SF solution, CS solution and nHA suspension were mixed in vitro at equal proportions.The progressive gradient osteochondral(OC)scaffold-1(2%), scaffold-2(3%)and scaffold-3(4%)was respectively prepared by using centrifugation, vacuum freeze-drying, chemical cross-linking and three shaping steps.General conditions, porosity, hot water dissolution rate, water swelling rate, compression water swelling rate, water swelling rate after dissolution, mechanical properties, internal structure observation and pore size were measured.Rat bone marrow mesenchymal stem cells(BMSCs)were cultured and the scaffold extract was prepared.The effect of scaffold extract on the proliferation of BMSCs was detected by the cell counting kit-8(CCK-8)method.BMSCs were co-cultured with the scaffold, and the distribution and morphology of the cells around the scaffold were observed.Results:The structure of scaffold was regular in each group and the porosity was more than 80%.Along with the increase of the material concentration, the water swelling rate of the scaffold was decreased gradually( P<0.05). Compared with before compression, the water swelling rate of scaffold-1 was decreased after compression( P<0.05). There was no significant difference in the hot water dissolution rate among all groups( all P>0.05), and the complete dissolution of the scaffold-1, scaffold-2 and scaffold-3 in vitro required 65.9, 60.9, and 73.9weeks, respectively.The elastic modulus of scaffolds in above three groups were 0.0955, 0.1762 and 0.3468 MPa, respectively.The examination results of scanning electron microscope(SEM)showed that the internal structure of scaffold was honeycomb in each group, the pore shape was regular, which showed an inter-connected pore network.The pore distribution was gradually dense and the pore diameter gradually decreased from the cartilage side to the osteogenic side( P<0.05), and the nHAp content increased gradually.The scaffold extract had no obvious toxicity to the growth and proliferation of BMSCs in each group.After BMSCs were seeded on scaffolds and co-cultured for 5 days, the cells grew well without obvious cell death or morphological abnormalities. Conclusions:In this study, a progressive gradient pore size OC scaffold is successfully prepared with good physical properties and biocompatibility, which is expected to be a new bio-mimetic composite scaffold material for repairing OC defects.
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Objective To explore the feasibility and methods of preparing silk fibroin(SF)/ chitosan(CS)/nano hydroxyapatite(nHA)composite osteochondral scaffolds with a gradient pore size structure.Methods We prepared an SF solution,a CS solution and an nHA suspension,all with a 2％ concentration,and mixed them with equal proportions.The mixture was used to prepare SF/CS/nHA composite osteochondral scaffolds with a pore size gradient through a centrifugal freeze drying and chemical cross linking method.The porosity,hot water loss rate,water swelling rate and mechanical properties of the scaffold were measured,and the dissolution curve and stress strain curve were drawn.The internal structure and morphology of the scaffold were observed by scanning electron microscopy(SEM)and the sizes of pores in the scaffold were measured.Results The porosity of the scaffold was(91.30± 3.35)％;The five week hot water loss rate was(16.57± 3.18)％;And the water swelling rate was (3218.53 ± 84.37)％.Mechanical test results demonstrated a good compression performance of the scaffold.SEM showed that the internal pores of the scaffolds were honeycomb structured with communicating passages;The density of pores gradually increased with decreasing pore sizes from the top to the bottom(pore sizes at four different levels:(141.11± 11.85)μm,(119.94± 9.05)μm,(93.10 ± 14.98) μm,and (79.95 ± 8.65)μm,respectively,F =22.973,P =0.000).Scaffold cytotoxicity test results indicated no significant difference between A values of the extract group and of the negative control group at any time point(t24 h =0.520,P =0.610;t48 h =0.665,P =0.515;t72 h =0.439,P =0.666),and all RGR values were greater than 100％.Conclusions SF/CS/nHA composite osteochondral scaffolds with a gradient pore size structure can be prepared with a centrifugal-freeze drying and chemical cross-linking method.Scaffolds prepared this way have a three-dimensional structure,a gradient pore size structure,high porosity,strong water absorption,suitable degradation rates and good compressive resistance.Besides,the good cell compatibility and low cytotoxicity of the scaffolds satisfy the requirements for osteochondral tissue engineering materials.
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BACKGROUND:Gene-enhanced tissue engineering can promote the proliferation and differentiation of seed cells,reduce allogeneic immunity,promote vascularization,and facilitate the repair of osteochondral defects.OBJECTIVE:To observe the effect of lentivirus-mediated human bone morphogenetic protein-2 (BMP-2) transfected rebbit adipose-derived stem cells (ADSCs) cultured on polylactic acid/polyglycolic acid copolymer scaffold (PLGA) on osteochondral defect repair.METHODS:Thirty male New Zealand rabbits were randomly divided into control group (n=15) and experimental group (n=15).Animal models of bilateral femoral cartilage defects were made in all rabbits.The experimental group was implanted with BMP-2-enhanced ADSCs/PLGA copolymer scaffold,and the control group was implanted with ADSCs/PLGA copolymer scaffold.In both groups,autologous osteochondral mosaicplasty was then performed.After 3 months of implantation,bone tissues at defect region were taken for biomechanical and proteoglycans detection.Histological observation was done at 3,6,12 months after implantation.RESULTS AND CONCLUSION:(1) The compressive modulus and proteoglycan content of the experimental group were significantly higher than those of the control group at 3 months after implantation (P ＜ 0.01).(2) At 3,6 and 12 months after implantation,with the increase of postoperative time,the joint surface in the experimental group became more and more smooth,the color became more and more shallow,and the healing degree of the defect increased to different extent.However,there were no obvious changes in the joint surface,color,morphology and histomorphology in the control group.To conclude,BMP-2-enhanced ADSCs/PLGA copolymer scaffold could significantly promote the repair of osteochondral defects.
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<p><b>OBJECTIVE</b>To investigate the decrease of bone mineral density in female patients, effects on acetabular displacement.</p><p><b>METHODS</b>From October 2013 to November 2015, a total of 34 patients underwent total hip replacement in the Department of orthopedics, the Third Affiliated Hospital of Zunyi Medical College. The two groups of patients were female and the patients were treated with hip osteoarthritis. Based on the lowest value of preoperative dual energy X-ray bone mineral density (DXA), the patients were divided into normal group and low bone mineral density(-3.5<=T<=-1). There were 10 patients in the normal group, ranging in age from 55 to 64 years old, with an average of (58.00±4.22) years old. There were 24 patients in the low bone density group, ranging in age from 58 to 72 years old, with an average age of (65.71±8.19) years old. All the patients received a THA implant with ceramic-on-ceramic bearings(Depuy America). The lining system was Pinnacle cup. During the operation, the acetabular cup was maintained at abduction 45 degree and anteversion 15 degree. Analysis (RSA) of acetabular components in 3, 6, 12, and 24 months after surgery.</p><p><b>RESULTS</b>There was a statistically significant difference in cup migration between patients with normal BMD and those with low BMD. At 3 months, compare to the normal group, the low bone mineral density (BMD) occurred in the X axis (95% confidence interval, 0.01 to 0.31;=0.006) and Y (95% confidence interval 0.20 to 0.39;=0.003). The initial rotation occurs in a separate Z axis(95% confidence interval -0.26 to 0.81;=0.006).</p><p><b>CONCLUSIONS</b>It has produced that increaseed migration of uncemented cups in female patients with low systemic BMD in 3 months after surgery.</p>
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Objective To study the effects of environmental factors,including high temperature,high humidity and low temprtature,on the quality of whole blood.Methods Fresh blood was collected from 9 blood donors and divided into 40 parts.One group that comprised 20 samples was used to assess the effects of storage at high temperature and high humidity (0,3,6,12 and 24 h),and the other group(20 samples)was used to determine the effects of low temprtature(0,1,2 and 3 h).The serum free hemoglobin(FHb)concentration, plasma prothrombin time(PT), activated partial thromboplastin time(APTT),thrombin time(TT)and fibrinogen(FIB)were measured and analyzed.Results The high temperature(27-37℃)and humidity(60%-90%RH)had no effect on FHb, PT, APTT, TT or FIB of whole blood. The low temperature(0-13℃and -18--20℃)had some effect on the quality of whole blood.The FHb of test group was higher than that of control group.There was no significant difference in PT, APTT, TT and FIB between the two groups.Conclusion Under high temperature and humidity conditions, 24 hours of whole blood placement is feasible. Under low temperature or cold conditions,short-term whole blood placement is feasible in a tent with heating facilities.
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BACKGROUND:Bone morphogenetic protein-2 (BMP-2) is a key to bone formation and repair.However,it has some disadvantages such as easy to lose and degrade and difficult to sustain continuous effect.OBJECTIVE:To study the preparation and properties of silk fibroin/chitosan/nano-hydroxyapatite (SF/CS/nHA) scaffold loading BMP-2.METHODS:After silk degumming,dissolution and purification,2％ SF solution was obtained.BMP-2 was dissolved in 2％ CS solution,and then fully mixed with equal volume of SF solution and proper amount of nHA.At last,the SF/CS/nHA scaffold loading BMP-2 was prepared using freeze-drying method as experimental group.The SF/CS/nHA scaffold was soaked in the BMP-2 solution as control group.The scaffold porosity was measured by Archimedes method,the surface morphology of the scaffold was observed by scanning electron microscope,the compressive strength was measured by universal testing machine.Scaffolds in the two groups were soaked in PBS,and the release of BMP-2 was measured by ELISA method at different time points.RESULTS AND CONCLUSION:(1) The scaffolds in the two groups had irregular porous structure,interconnected pores and uneven pore wall.There was no significant difference between the two groups in mean pore diameter,porosity and maximum compressive strength.(2) On the 1st day,the release rate of BMP-2 was 4.63％ in the experimental group,and the release curve increased slowly.After 28 days,the release curve of BMP-2 was transferred to the plateau stage.But in the control group,the release rate of BMP-2 on the 1stday was 58.84％,and it was a significant initial burst release.The release curve increased rapidly,and was transferred to the platform stage on the 10th day.The release rate of BMP-2 release was significantly different between the two groups at days 1,2,4,10 (P ＜ 0.05).These results show that the SF/CS/nHA scaffold loading BMP-2 could sustainably and slowly release BMP-2.
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<p><b>OBJECTIVE</b>To elucidate the molecular and electrophysiological mechanisms of Brugada syndrome through functional analysis of a novel SCN5A gene mutation G1712C.</p><p><b>METHODS</b>A recombinant plasmid pRc<CMV-hH1 containing the mutant human cardiac sodium channel α subunit (hH1) cDNA was constructed using in vitro PCR-based site-directed mutagenesis technique. LipofectamineTM 3000 was used to transfect the plasmid DNA into HEK293 cell line to induce stable expression of Nachannel β1-subunit, and the positive colonies were selected by screening with G418.The standard liposome method was used to transiently transfect HEK293 cells with either the wild-type or mutant Nachannel subunits (hH1 and mhH1, respectively), and the macroscopic Nacurrents were recorded using whole-cell patch-clamp technique. Data acquisition and analysis, generation of voltage commands and curve fitting were accomplished with EPC-10, PatchMaster and IGOR Pro 6.0.</p><p><b>RESULTS</b>An HEK293 cell line that stably expressed Nachannel β1-subunit was successfully established. After transient transfection with the WT subunit, large Nacurrents were recorded from the stable β1-cell line. Transient transfection with the G1712C subunit, however, did not elicit a Nacurrent in the cells.</p><p><b>CONCLUSION</b>Compared with normal Nachannel, the wild-type channel exhibits a similar sodium current. The characteristic kinetics of sodium channel of WT-hH1 was identical to that in normal cardiac muscle cell, and the missense mutation (G1712C) in the P-loop region of the domain IV may have caused the failure of sodium channel expression.</p>
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Humans , Brugada Syndrome , Genetics , Genotype , HEK293 Cells , Mutagenesis, Site-Directed , Mutation , Genetics , Patch-Clamp Techniques , Polymerase Chain Reaction , TransfectionABSTRACT
OBJECTIVE To observe the protective effect and underlying mechanism of total ginsenosides (TG) on bleomycin-induced pulmonary fibrosis. METHODS Intratracheal instillation of bleomycin 5 mg · kg-1 was conducted to establish a pulmonary fibrosis mouse model. Kunming mice(1/2 males and 1/2 females)were randomly divided into sham-operation(Sham),model,total ginsen?osides 40,80 and 160 mg·kg-1 and prednisone acetate(5 mg·kg-1) groups. After 28 d administration,the histopathological changes in the lung were analyzed by hematoxylin eosin(HE)and Masson staining. The exprssion of alpha smooth muscle actin(α-SMA)in the lung was detected by real-time PCR. The content of hydroxyproline(HYP)and glutathione(GSH),level of total antioxidant capacity(T-AOC)and hydroxy radical(·OH),activity of myeloperoxidase(MPO)and nitric oxide synthase(NOS)in the lung were detected by corresponding kits. RESULTS Compared with the sham group,the pulmonary indexes in model group were significantly increased(P<0.01),alveolitis and pulmonary fibrosis were obvious. The mRNA expression ofα-SMA,content of HYP and · OH,activity of MPO and NOS were increased(P<0.05),but the content of GSH and T-AOC in model group was decreased(P<0.05). Compared with model group,the pulmonary indexes in TG 80 and 160 mg · kg-1 and prednisone acetate 5 mg · kg-1 groups were reduced(P<0.05),and the degree of alveolitis and pulmonary fibrosis was mitigated. The mRNA expression ofα-SMA,content of HYP and · OH, the activity of MPO and NO were decreased (P<0.05),while the content of GSH and T-AOC was increased(P<0.05). CONCLUSION TG can improve the degree of mice pulmonary fibrosis induced by bleomycin. The mechanism may be related to the increased antioxidant capacity of organisms.
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Objective To explore humam cytomegalovirus(HCMV) encoded microRNAs during latent infection in order to help study HCMV virology and latent infection mechanisms.Methods A model of HCMV latent infection via THP-1 cells infected with HCMV was constructed.Deep-sequencing was performed using high-resolution Solexa sequencing platform.The secondary structure of the newly sequenced miRNA was predicted by RNAFold bioinformatics software. Results HCMV encoded various miRNAs during latent infection, including miR-US25-2-3p, miR-US25-2-5p, miR-UL112, miR-US25-1, miR-UL22A and PC-5p-148467 with a predicted length of 25 bp, named hcmv-miR-US33as-5p.Conclusion HCMV can express many types of miRNAs during latent infection.
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In order to prevent the dislocation of total hip arthroplasty (THA) and reduce the wear rate, the position of the acetabular component in THA is very important. However, due to the influence of many potential factors, the accurate implantation of the acetabular component in the operation is still a challenge. Lewinnek safety zone positioning the cup anteversion angle (15±10)°, abduction (40±10)°, has been regarded as acetabular prosthesis installation standards, in an attempt to reduce the risk of instability, but there are still reported a dislocation. Based on the Lewinnek safety zone, Ha proposed the use of acetabular anatomical landmarks. According to patient specific shape positioning the position of the acetabular component methods are used to determine the specificity of the target area, thereby reducing the impact of hip replacement, and to maintain a lower liner wear rate. Image navigation system can improve the positioning of acetabular cup, but it is affected by many factors, such as high cost, difficult operation and so on.
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Objective To investigate the influence of recombinant human bone morphogenetic protein‐2(rhBMP‐2)of poly lactic acid(PLA) release microspheres for compatibility of rabbit bone marrow mesenchymal stem cells(BMSCs) .Methods The rh‐BMP‐2‐PLA release microspheres were prepared by w/o/w multiple emulsion volatilizing method and then cocultured BMSCs .The effects of rhBM P‐2‐PLA release microspheres on the cytotoxicity and relative proliferation rate by MTTassay .Evaluation of mate‐rials biocompatibility by inverted microscope and scanning electron microscope(SEM) .Results The rhBMP‐2‐PLA release micro‐spheres in various concentration of leaching solution and BMSCs training of uninfected cells .Experimental group and control group in 4 different time cell proliferation OD values by analysis of repeated measurement variance between time OD values were statisti‐cally significant(P=0 .000) ,the experimental group and control group OD values are statistically significant(P=0 .025) ,the exper‐imental group higher than the control group ,experimental group OD value time there was a significant interaction effect and the group number ,the change trend are obviously different(P=0 .006) .Inverted microscope to observe materials normal cell prolifera‐tion ,SEM found that vaccination cells surrounding rhBMP‐2‐PLA release microspheres of 7 days later ,the cells grew well and split proliferation activity .Conclusion rhBMP‐2‐PLA release microspheres of BMSCs has non‐toxic and has compatibility .
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Objective To study the effect of HCV receptors′sequence on virus entry based on the two-dimensional structure and via tandem expression of HCV receptors on mouse hepatocytes.Methods The construced recombinant expression vectors pCDH-hLDLR-hSR-BⅠ-hCD81-GFP, pCDH-hLDLR-hCD81-hSR-BⅠ and pCDH-hCLDN-1-hOCLN-DsRed were cotransfected into 293FT cells with package vectors.The collected recombinant lentivirus expressing hCLDN-1-hOCLN was concentrated and attacked mouse hepatocytes.The transgenic mouse hepatocytes with tandem overexpression of CLDN-1 and OCLN were established after G418-selection.The transduced cells LSCCO/Hepa1-6 and LCSCO/Hepa1-6 were sorted via flow cytometry and puro-G418-selection after recombinant lentivirus expressing hLDLR-hSR-BⅠ-hCD81 and hLDLR-hCD81-hSR-BⅠattacked Hepa1-6 respectively.The infectivity of transduced mouse hepatocytes LSCCO/Hepa1-6 and LCSCO/Hepa1-6 to HCV was analyzed via direct-infection of serum-derived virus.Furthermore, the effect of HCV receptors′sequence on virus entry was studied.Results Both LSCCO/Hepa1-6 and LCSCO/Hepa1-6 enhanced HCV-cell binding.The transduced mouse hepatocytes LSCCO/Hepa1-6 had more HCV endocytosis.Conclusion SR-BⅠhas priority over CD81 in HCV entry in the early stage.
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BACKGROUND:Poly lactic acid as an excellent delivery has good biocompatibility. OBJECTIVE:To prepare recombinant human bone morphogenetic protein-2 (rhBMP-2)/poly lactic acid (PLA) sustained release microspheres, and to study its physical and chemical properties. METHODS:The rhBMP-2/PLA sustained release microspheres were prepared using w/o/w solvent evaporation method. Scanning electron microscopy, laser particle size, zeta potential, and swel ing properties were detected. ELISA kit was utilized for measurement of encapsulation efficiency, drug-loading rate and in vitro drug release rate. RESULTS AND CONCLUSION:Under the scanning electron microscope, rhBMP-2/PLA sustained release microspheres were approximately circle with excellent dispersion. The uniform spheres were visible with a mean particle size of 839.6 nm. The zeta potential were (-32.93±3.74) mV. The swel ing coefficient was 1.157±0.059. The drug-loading rate and encapsulation efficiency of rhBMP-2/PLA sustained release microspheres were (88.943±2.878)%and (0.026±0.001)%respectively. The drug release rate at 1 day was about 10.199%, then the drug release was relatively constant, and til 19 days, the cumulative drug release rate was 54.643%. These findings indicate that the constructed rhBMP-2/PLA sustained release microspheres meet the requirement of the Chinese Pharmacopoeia (10th edition) that the encapsulation efficiency is not less than 80%and the microspheres have a good slow-release function in vitro.
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BACKGROUND:Silk fibroin/chitosan/nano hydroxyapatite (SF/CS/nHA) composite scaffold constructed in preliminary experiments has good physical and chemical properties. OBJECTIVE:To study the capacity and mechanism of SF/CS/nHA composite scaffold for repair of rabbit radial bone defects. METHODS:Thirty-six New Zealand white rabbits were selected to make animal models of right radial bone defects, and then randomly divided into SF/CS/nHA group, SF/CS group and blank control group. Blank control group had no treatment after modeling. X-ray radiography, gross observation and histopathological observation were performed at 4, 8, 12, 16 weeks postoperatively. RESULTS AND CONCLUSION:Sixteen weeks after surgery, bone defects in the SF/CS/nHA group were completed replaced by normal bone tissue on X-ray images, and the bone marrow cavity showed complete recanalization with new bone formation;hematoxylin-eosin staining showed bone trabecula and many fusiform bone cells. In the SF/CS group, the bone mineral density in the defect area was slightly lower than that of the normal bone tissues, the bone marrow cavity was partly rehabilitated, and many chondrocytes were seen around bone cells that arranged irregularly with no bone trabecula or bone lamel a. In the blank control group, the images of bone calcification were consistent with normal bone tissues, and a closed bone ununion was formed at each end;hematoxylin-eosin staining showed that the blank control group was fil ed by fibrous connective tissue and a smal amount of bone-like tissues. SF/CS/nHA composite scaffold is better for repair of rabbit radial bone defects.
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Objective: To investigate the protection of Angelica sinensis extract on the left ventricular hypertrophy (LVH) of rats and explore the possible mechanisms. Methods: Male SD rats were randomly divided into Sham, model, and low-, mid-, and high-dose A. sinensis extract (25, 50, and 100 mg/kg), and L-arginine (200 mg/kg) positive control groups. Except for Sham group, the rats with LVH were induced by abdominal aorta coarctation and were administered from the next day after surgery once daily for consecutive 21 d. Changes of cardiac hypertrophy parameters and hemodynamic indexes of rats were observed. Left ventricular myocardial fiber diameter (MD) was determined. Electron microscopy was used to observe the ultrastructure of myocardial tissue. RT-PCR was used to determine the mRNA expression of atrial natriuretic factor (ANF) and calcineurin phosphatase (CaN). Western blotting was used to determine the expression of α-subunit of calcineurin phosphatase (CnA). Results: Compared with Sham group, the left ventricular hypertrophy index (LVHI), the left ventricular weight/right ventricular weight (LVW/RVW), and MD were remarkably increased, the expression of ANF, CaN mRNA, and CnA protein was obviously elevated. A. sinensis extract could remarkably decrease LVHI, tend to or significantly decrease LVW/RVW, improve the indicators of systolic and diastolic function, and down-regulate the expression of ANF, CaN mRNA and CnA protein. Conclusion: A. sinensis extract has the protection against LVH induced by abdominal aorta coarctation in rats, and the mechanism may be related to its inhibitory effects on CaN signaling pathway.
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BACKGROUND:Silk fibroin, chitosan, and nano hydroxyapatite are natural materials, and they al have good biological activity and physical or chemical properties. As tissue engineering materials, they have been already widely used in clinic or research work, but there are some defects in the application of these three kinds of materials. OBJECTIVE:To discuss the preparation and characteristics of silk fibroin/chitosan/nano hydroxyapatite complicated scaffolds which could be used in bone tissue engineering. METHODS:Silk fibroin, chitosan, and nano hydroxyapatite were separately prepared into 2%solution, and then mixed at the ratio of 1:1:0.5, 1:1:1, 1:1:1.5 respectively. The three-dimensional complicated scaffolds were prepared by those mixed liquids through repeated freeze drying and chemical crosslinking technology. Scanning electron microscope was used to detect the pore size of the scaffolds. Porosity, water absorption rate, and hot-water loss rate were determined. Mechanical tester was used to measure the tensile and compressive modulus of dried three-dimensional scaffolds. RESULTS AND CONCLUSION:The silk fibroin/chitosan/nano hydroxyapatite complicated scaffold in the dry state had no special smel , appeared to be a stabilized solid cylinder, and exhibited clear resiliency and flexibility with a touch. With the increased content of nano hydroxyapatite, the porosity, water absorption rate and average pore size of the scaffolds appeared to be decreased, while the hot-water loss rate and compressive strength were increased. The scaffold prepared at 1:1:1 was better for bone tissue engineering, and the average pore size, water absorption rate and hot-water loss rate were 85.67 μm, (135.65±4.56)%and (22.84±1.06)%, respectively, closer to the needs of the bone tissue engineering. Uniform pores were found within the scaffold at 1:1:1, showing the network structure, developed transport among pores, and the network structure was approximately 10μm.
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Objective To investigate the feasibility of restoration of cartilage defect with silk fibrin/chitosan(SF-CS)biological scaffold compound by induced bone marrow mesenchymal stem cells (BMSCs)in the elderly rabbits.Methods BMSCs were extracted,cultured and induced to differentiate,then inoculated into SF-CS three-dimensional scaffold restoration.54 rabbits(aged 16-18months)were divided into scaffold restoration,single scaffold and control groups(n=18 per group).The right knee joint was used for building cartilage defect model and implanted by scaffolds.General observation,tissue staining and modified Wakitani histological scoring were performed at 4,8 and 12weeks after operation.Results SF-CS scaffold was structured by multiple interlinked pores.The average pore size was 151.72 μm.The porosity was(92.72±4.78)％.The imbibition rate was (141.10± 6.87)％.BMSCs was grown well and proliferated dynamically in SF-CS scaffold after induction.At 12 weeks,the cartilage defect was basically repaired,type Ⅱ collagen was positively expressed and the scaffold was almost assimilated in scaffold restoration group.In single scaffold group,the cartilage defect was repaired mainly by fiber tissue,type Ⅱ collagen was less expressed and the scaffold almost degraded while the cartilage defect was repaired badly in control group.The scaffold restoration group was superior to single scaffold and control groups(P＜0.05)in improving the Wakitani score.Conclusions The SF-CS scaffold as BMSCs carrier may restore cartilage defect in knee joint of the elderly rabbits.
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Pharmacology is the bridge of preclinical and clinical medicine,as well as medical science and pharmaceutical sciences.Guiding students to grasp some memory method will make for inspiring student's thinking and increasing their interest in pharmacology teaching.And it will also help to improve the effect of pharmacology teaching.
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Objective To report one stage treatment of chronic tibial defection in children. Methods 19 children with chronic tibial defection were treated in our department when their infection was at the stage of latency. First their focuses of infection were cleared away. Next a piece of fibula with vessel pedicles whose length was equal to that of the tibial defect was taken as the support to restore the length of the tibia. Then the external fixators were applied and a mixture of antibiotic and Lebone powder was used to fill the defect. Results In 15 cases the incision healed at one stage, slight infection occurred in 4 cases whose incisions healed after treatment of 3 to 4 weeks. Follow-ups of 0.5 to 1.5 years showed that no infection occurred again, bone defects healed well and limb function was satisfactory. Conclusion To treat chronic tibial defection in children at one stage, combined therapy should be applied. Grafting of fibula with vessel pedicles and Lebone under external fixators is a good one, because it can shorten the treatment time at no cost of satisfactory effects.