The phenotypes of human fetal thymocytes has been analysed with fflowcytometry.The findings suggest that the composition of thymocyte subsets shows no obvious changes from the 17th week of gestation to birth.In the pieriod of human fetus,features of thymocyte phenotypes are showed:1.Expression density of CD3/TCR?? shows a continuous distribution from low to high.According to the density of D3/TCR??,tyhmocytes can be divided into three subsets,that is,L—CD3/TCR??(low—density),M—CD3/TCR?? medium—density)and H—CD3/TCR??(high— density).The proportion of three subsets is different in different fetuses.2.Single positive thymocytes express CD1 antigens.H—CD3/TCR?? thymocytes also express CD1 antigens.But,Part of those thymocytes express low—density of CD1 antigens,other part of the hymocytes express high—density of CD1 antigens.3.HLA class Ⅰ antigen density varies with thymocytes.Most thymocytes express low density of HLA class Ⅰ antitgens,minor thymocytes express high density of HLA class Ⅰantigens.HLA class Ⅰ antigen density correlates with maturity of thymocytes.4.Thymocytes can be divided into two subsets:Thy-L and Thy-H on the basis of thymocyte special density by means of density gradient centrifugation.Thy-L subset includes more mature and early thymocytes than Thy-H subset,while thy-H subset includes much more common thymocytes than Thy-L subset.

BACKGROUND:Three-dimensional (3D) nanofiber scaffolds are aimed to mimic the physical and chemical signals of stem celsin vivo. 3D nanofiber scaffolds, which are capable to maintain the activity of stem cels, are promising in tissue regeneration and stem celltherapy. OBJECTIVE:To review the synthesis methods for 3D nanofiber scaffolds, and the interactions of stem cels and 3D scaffolds as wel as the current progress of 3D nanofiber scaffolds in tissue engineering. METHODS:Web of Science was searched with key words of “tissue engineering, nanofiber scaffold, stem cellfate” in English for articles relevant to stem celltissue engineering and 3D nanofiber scaffolds. RESULTS AND CONCLUSION:3D nanofiber scaffolds can mimic the physical architecture ofin vivo microenvironment due to its nano-scale topology. Chemical modification of scaffolds endows chemical cues to stem cels. Therefore, 3D nanofiber scaffold can be a promising delivery vehicle of stem cels in tissue engineering. Nanofiber scaffolds can be synthesized through self-assembly, sol-gel phase separation, and electric spinning. 3D nanofiber scaffolds have been shown to improve thein vitro proliferation of hematopoietic stem cels, embryonic stem cels, mesenchymal stem cels, and neural stem cels. 3D nanofiber scaffolds with specific topology/chemical properties can induce the differentiation of stem cels into bone, cartilage, nerve, or muscle. 3D nanofiber scaffold which provides a satisfactory microenvironment for stem cellenhance the performance of stem celltherapy.

BACKGROUND:Construction of tissue engineering adult cardiac myocytes has been a new research hotspot in cardiovascular fields.
OBJECTIVE:To explore a simple, fast method for the separation of adult rat cardiomyocytes, and preliminarily explore the construction methods of tissue engineering adult cardiac myocytes.
METHODS:Segmented enzymatic digestion method was used to isolate cardiac myocytes from adult rats. Subsequently, cardiac myocytes were transfected with adenovirus and liposome-mediated red fluorescent protein gene. Construction efficiency of tissue engineering cells was qualified using inverted fluorescence microscopy and flow cytometry. Final y, cardiac myocytes were transfected with adenovirus-mediated hypoxia-inducible factor-1a, and the expression of hypoxia-inducible factor-1a was examined by western blot analysis.
RESULTS AND CONCLUSION:A lot of cardiac myocytes were col ected using the segmented enzyme digestion method. Flow cytometric analysis showed that the survival of adult cardiomyocytes was (87.03±0.70)%. Compared with liposomal transfection (transfection efficiency was 0), adenovirus infection efficiency was (70.31± 1.39)%, and the cells expressed red fluorescence under fluorescence microscope. After 4 days of adenovirus infection, transfected cells expressed hypoxia-inducible factor-1a protein. These results showed that segmented enzyme digestion is a fast way to isolate adult cardiac myocytes, and recombinant adenovirus vector is a good vector to transfect cardiac myocytes.

Objective:To evaluate the effects of different ultrasonic retroprep tips on the root-end preparation in cadavers.Methods:34 anterior teeth in situ in maxillary and mandibular jaws in cadavers were chosen and the root-end of 3 mm of all teeth was exposed. Root canal was prepared and filled with gutta-purcha in all teeth,3 mm of the root end was cut off.The teeth were divided into 2 treat-ment groups(n=1 5),and 1 control group(n=4).The root-end preparation was made using ultrasonic diamond tip and stainless steel tip respectively to 3 mm depth.The teeth in control group were not treated.Microcracks,marginal integrity and gutta-percha clearance were observated under SEM.Results:Diamond ultrasonic tips provoked a smaller number of cracks(P=0.059)and destroy of margin-al integrity(P=0.269)than stainless steel tips.Less gutta-percha clearance was produced by stainless steel tip than that by diamond ultrasonic tip(P=0.006).Conclusion:Diamond ultrasonic tip is more suitable for root-end preparation.

Objective To study the role of corn oil in the change of serum glucose, serum lipids and insulin in type 2 diabetes rats with insulin resistance, and attempt to find out its mechanism. Method High fat and sugar diet plus low-dose streptozotocin (STZ) was given to establish type 2 diabetes rat with insulin resistance model, the rats of which were randomly divided into normal group, model group, corn oil (0.8 mg/kg) group, rosiglitazone group. After Ig 6 weeks, fasting blood glucose (FBG), total cholesterol(TC), triglyceride(TG), low density lipoprotein(LDL), high density lipoprotein (HDL), fasting insulin (FINS), and insulin resistance index (HOMA-IR) were detected. Results Corn oil can elevate the level of HDL in diabetic rat, lower the levels of FBG, TC, TG, LDL, FINS and HOMA-IR. Conclusion Corn oil can improve insulin resistance, and decrease the serum glucose and lipid of type 2 diabetic rats.

Objective To estimate the effective dose during 64-slice CT examination on head,chest and abdomen and determine the conversion coefficient of effective dose and dose length product(DLP).Methods The plain CT scan wag performed in 48 cases on head,50 cases on chest and 45 cages on abdomen using GE Lightspeed 64-slice spiral CT.1The Kv,Ma,scan time,CTDIvol,and DLP were recorded in each examination.Effective dose on patients Was estimated using the SR 250 software.Results The effective dose on head,chest and abdomen was(3.1±0.1),(6.9±0.1)and(8.0±0.1)mSv,and the conversion Coeffieient was 0.0025,0.0191 and 0.0166 mSv·mGy-1·cm-1 respectively.Conclusion CTDIvol、DLP and effective dose were recommended for patient dose control during CT examination.The conversion factor of effective dose and DLP were recommended for radiation risk evaluation during different X-ray examinations.

Objective to compare the calculated effective radiation dose variations in cardiac interventional procedures of coronary angiography (CAG) and percutaneous transluminal coronary angioplasty (PCI) by using the different tissue weighting factors recommended by ICRP Publication 60 with that recommended by ICRP Publication 103. Methods Measurements of organ doses were carried out with an anthropomorphic phantom equipped with thermoluminecent dosimetry. The effective radiation doses were separately calculated using the tissue weighting factors provided by ICRP 60 and provided by ICRP 103, and the results obtained from ICRP 60 were compared with that obtained from ICRP 103. Conversion factors of effective, radiation dose to dose area product (DAP) were also calculated according to different publication.Results The variations in the effective dose were 6.88% for CAG and 8.46% for PCI. The effective dose variations in CAG and PCI were. 7.25% and 8.76% for female and were 6.51% and 8.17% for male,respectively. The effective conversion factors of DAP were. 0.10 ～ 0.11 and 0.13 ～ 0.14 for CAG and PCI,respectively, according to ICRP 60 and 103. Conclusion The variation of conversion factors of effective dose indicates that in making estimation of effective radiation dose. by using the widely accepted conversion factors, the adjustment of organ weighting factors recommended by ICRP 103 should be considered.

Objective To observe the protective effect of Mongolian medicine Carthamus tinctorius in acute liver injury induced by D-GlaN(D-galactosamine)in rat models. Methods The acute liver injury model was established by intragastric administration D-GlaN in rats. The levels of serum aspartate aminotransferase(AST),alanine aminotransferase(ALT),glutathione(GSH-Px),the content of tumor necrosis factor-α(TNF-α)in liver tissue and the apoptosis of hepatocytes were determined. Results Mongolian medicine safflower can significantly reduce the activity of serum ALT and AST and liver tissue GSH-Px,and the degree of cell apoptosis;however,no obvious change of the TNF-αcontent was observed. Conclusion The Mongolian medicine Carthamus tinctorius has protective effect in D-GlaN-induced acute liver injury rats probably via anti-oxi-dative and anti-apoptotic abilities.

ObjectiveTo investigate the change of the platelet function in children with primary immune thrombocy-topenia (ITP) before and after treatment.MethodsThe platelet indices, immature platelet fraction (IPF%), immature platelet counts (IPC), granule membrane glycoproteins of platelet (CD62p, PAC-1, CD42b) were tested by automatic blood cell analyzer and lfow cytometry (FCM) in 18 children with ITP before treatment and after complete response and in 17 children undergoing elective surgery (control gourp).ResultsCompared with control group, MPV, PDW, P-LCR and IPF% were signiifcantly higher and PLT, PCT, IPC were signiifcantly lower in children with ITP. The expressions of three platelet membrane glycoproteins (PAC-1, CD62p, CD42b) were signiifcantly lower in children with ITP. After treatment, children with ITP achieved completely response. Compared with before treatment, MPV, PDW, P-LCR and IPF% were signiifcantly lower, and PLT, PCT, IPC, and the expressions of three platelet membrane glycoproteins (PAC-1, CD62p and CD42b) were significantly higher. ConclusionsThe platelet function is depressed and in status of low activity in children with ITP. The relative platelet indices provide new references for the diagnosis and the judgment of therapeutic effect in ITP patients.

The role of myeloid-derived suppressor cells (MDSCs)in promoting inflammatory response and immune escape of tumor cells and the mechanism by which MDSCs promote the development and progression of tumors are reviewed.This could provide a new way for the investigation of immunological mechanism of liver fibrosis and liver cancer.Besides,MDSCs may be an effective therapeutic target for liver cirrhosis and liver cancer.