Exosomes are naturally nanometer-sized (40-100 nm) vesicles that contribute to the communication among the cells through the proteins, lipids and RNA which they carried. Exosomes derived at different physiological conditions play different role, which therefore can be widely used in the diagnosis and treatment of cancer. Besides, exosomes as the natural nanomaterials have the unique advantage in drug delivery system. Although the intrinsic advantages of exosomes have evoked a surge of interest, improvements in standardized isolation techniques with high efficiency and robust yield are still a huge challenge. Here, we provide an overview of the isolation and the application of exosomes in drug delivery system.

BACKGROUND: Growth differentiation factor-5 (GDF-5) plays an important role in the development and formation of cartilage, extremities, and joints, which is a widely used joint development marker.OBJECTIVE: To express mature peptide of human GDF-5 in E. coil by the way of genetic engineering, and to explore the inductive activity of recombinant protein in vivo.DESIGN, TIME AND SETTING: The observation experiment based on gene was performed at the Analysis and Testing Center of Southern Medical University from January to June 2006.MATERIALS: Human fetus cartilage tissue was harvested from Department of Gynaecology and Obstetrics, and the consent was obtained from the family. Ten KM mice were purchased from experimental animal center of Southern Medical University, half male and half female, weighing 18-22 g, aged 6-8 weeks.METHODS: The hGDF-5 gene encoding mature peptide was gained by RT-PCR from the total RNA which was extracted from fetus cartilage tissues, and was inserted into the pET22b(+) vector to construct recombinant prokaryotic expression plasmid pET22b(+)-GDF5, which was transformed into E. coil BL-21 to be expressed after IPTG induction. Proteins of interest were purified with sepharose chelated with nickel ions (Ni2+) and then implanted in mouse hindlimb muscle to evaluate the biological activities by routine hematoxylin-eosin staining.MAIN OUTCOME MEASURES: The expression, sequencing of target gene was observed by agarose gel electrophoresis, and the protein expression was detected by SDS-PAGE electrophoresis, meanwhile, the GDF5-inducing activity was evaluate by histological observation.RESULTS: RT-PCR product was about 350 bp in length, which was confirmed by double enzyme digestion of the recombinant plasmid, sequencing result was in agreement with the reported hGDF-5 sequence in Genbank. SDS-PAGE analysis showed a conspicuous band representing a new foreign protein with relative molecular mass of approximately 14 KD after induced expressioin. Cartilage tissues were formed in the mouse muscle where the purified proteins were implanted. CONCLUSION: The integral human GDF-5 mature peptide gene was cloned successfully from human fetus cartilage tissue and a high-yield expression was achieved in E. coli, the pudfied protein has chondrogenic activities in vivo.

Objective In order to explore the biological features of bone marrow mesenchymal stem cells. Methods The ALPase activity, Vimentin and Laminin were detected by immunocytochemistry. Cell cycle and surface antigenic features were analyzed by flow cytometry technique. Cell growth curve was measured by MTT test. The telomerase activity was detected by in situ hybridization. Results The ALPase activity and Laminin were negative, Vimentin was positive in the MSCs. The percentage of G1, S, and G2 of cell cycle was 89.5%,7.8%,7.7%, respectively. MSCs were positive for CD166、CD29、CD44、CD105, and negative for CD34 and HLA-DR. The average doubling time of cells was 32 hours. The telomerase activity was positive. Conclusion The cultured cells were not hemopoietic stem cells or fibroblasts, but the MSCs that had not differentiated. Furthermore, it had relatively high proliferation ability.

Objective To investigate the feasibility of the committed differentiation of mesenchymal stem cells(MSCs) into tenocytes,the present study was carried out. Method NMP12 gene transfer to MSCs was performed with pEGFP C1 expressing vector by electroporation. Results Green fluorescence protein(GFP) expression was detected as early as 6h postelectroporation, peaked at 12h and could maintain 3 days. And then, GFP expression of some cells was weakened. Conclusion The results of the present study indicated that the successful transfection of MSCs was made, an the committed differentiation of MSCs into tenocytes was practicable

Objective To investigate the feasibility of committed differentiation of rhesus bone marrow mesenchymal stem cells (MSCs) into tenocytes induced by BMP12. Methods MSCs were transfected with pTARGETTM bearing BMP12 gene by electroporation. The transfected cells were identified by morphological observation and molecular biological measure. Results Under the observation of light microscope, the morphological features of transfected cells changed significantly compared to parental MSCs. RT-PCR data showed the transfected cells had the mRNA expression of BMP12 and collagen Ⅰ, but without that of collagen Ⅲ. 98.39% of the transfected cells were CD44+ and negative for HLA-DR. Conclusion BMP12 could induce MSCs into tenocytes, and bone marrow MSCs might be the optional seed cells for tendon tissue engineering.

Higher education of South Korea's traditional medicine,based on the practical situation,has found a characteristic way of descending its traditional medicine,laid a solid foundation for the development of South Korea's traditional medicine.The authors introduced their admission mode,academic settings,construction of and teaching staff,and put forward some enliightenments on it so as to push the progress of our Chinese medicine.

Objective To observe the therapeutic effect of acupuncture plus blood-letting with three-edged needle for the acute stage of Bell's palsy of wind-heat syndrome in TCM.Methods The 100 patients were randomized into treatment and control groups with 50 in each,and treated with acupuncture plus blood-letting with three-edged needle and only acupuncture respectively.Four courses of treatment were given.The main symptoms,signs and clinical efficacy were observed at 1 week,2 weeks and 1 month after treatment.Results In both groups,the scores of symptoms and signs before and after treatment were remarkably different(P

Objective To investigate the insulin sensitivity in children born small for gestational age without catch-up growth.Methods We investigated 439 outpatients in pediatric department of the Third Hospital of Peking University with diagnosis of short stature from August 2008 to August 2016.Two groups were divided based on their diagnosis as born small for gestational age group(SGA)with 218 patients and idiopathic short stature group(ISS)with 221 patients.Fasting blood-glucose,fasting insulin,fasting insulin/fasting blood-glucose,islet beta-cell function(HOMA%),homeostasis model assessment-insulin resistance(HOMA-IR)were analyzed in two groups.Results Hierarchy based on age and sex in SGA and ISS.No significant difference was observed in preadolescent boys with fasting blood-glucose(4.7±0.6 vs 4.8±0.6,P=0.678),fasting insulin(5.1±4.0 vs 4.3±4.7,P=0.345),fasting insulin/fasting blood-glucose,HOMA%,HOMA-IR.No significant difference was observed in preadolescent girls with fasting blood-glucose(4.5±0.5 vs 4.6±0.5,P=0.828),fasting insulin(4.7±3.5 vs 4.5±3.3,P=0.603),fasting insulin/fasting blood-glucose,HOMA%,HOMA-IR.No significant difference was observed in adolescent boys with fasting insulin(5.9±4.3 vs 6.0±4.5,P=0.958),fasting blood-glucose(5.0±0.8 vs 4.9±0.5,P=0.176),fasting insulin/fasting blood-glucose,HOMA%,HOMA-IR.No significant difference was observed in adolescent girls with fasting blood-glucose(4.9±0.6 vs 4.8±0.4,P=0.141),fasting insulin(7.5±6.4 vs 7.4±8.6,P=0.448),fasting insulin/fasting blood-glucose,HOMA%,HOMA-IR.Conclusion The insulin sensitivity were in good condition in children born small for gestational age without catch-up growth.

Objective To investigate the correla tion between the plasma endothelin (ET) and gastric mucosal pathology.Methods In this experiment,seven dogs who exper ienced common bile-duct ligation were in experiment group, the other three dogs who underwent sham-operation were control group. By using specific radio immun ological method, the plasma ET levels were determined in dogs before and after 1 ,4,7 d. The total bilirubin levels were determined before and after 1,4,7 d afte r operation by using carbazotic acid method.The gastric mucosa,7 d after operati on, was cut into slices and was examined under the electron microscope and the l ight microscope.Results In the experiment group,the levels of ET and total bilirubin rose continually and were higher than those in control gr oup. Vascular congestion and oedema were seen in gastric mucosa of common bile- duct ligated dogs. Under the electron microscope, we could see the dilated bloo d capillary and sludging of blood,the intenstitial mucusa cells oedema. Conclusion The increase of plasma ET might lea d to impairment of mucosal micro-circulation,which might be one of the pathogen s that could induce the gastric mucosal damages in common bile-duct ligated dog s.

Objective To study the relationship between anti-? 2-glycoprotein I(a? 2GPⅠ) and extracellular matrix (ECM) in patients with post-hepatitis B cirrhosis (PHBC).Method The of patients with chronic hepatitis B (CHB) and PHBC were studied for the serum a? 2GPⅠ levels by ELISA with purified ? 2GPⅠ as antigen, and we investigated serum level of collagen IV (IV-C)?hyaluronic acid (HA) and laminin (LN) in these patients.Result High positive rate was observed compared with control group (P