Objective: To test the mechanical properties o f N48 NdFeB magnet.Methods:Samples of N48 NdFeB magnet in the size of 2 mm?3 mm?4 mm were prepared, the residual flux density,coercive force and maximum energy product of the samples were measured, the magnetic density aroun d the magnets,the attractive and repulsive force between two magnets in 0~10 mm air gap were investegated.Results:The residual flux density of t he N48 NdFeB magnet was 1.373 T, coercive force 1 037 A/m and maximum energ y product 368 kJ/m 3.The magnetic density at magnet surface was 0.338 T,it decr eased to 0 at the point that leave magnet surface 20 mm away. The highest attrac tive force was 4.47 N between two magnets, the attractive force was 4.47~0.39 N in 0~5 mm air gap.The highest repulsive force was 2.82 N and the repulsive force was 2.82~0.39 N in 0~5 mm air gap.Conclusion:The magnetic and m echanical properties of the N48 NdFeB magnet can meet the standard of the orthod ontic force.

Objective To investigate the application of position vector in balance evaluation of stroke patients with hemiplegia.Methods The static balance of 30 healthy subjects and 30 stroke patients with hemiplegia was measured by the balance instrument when standing on a force plate with eyes' open.There were 10 patients tested before and after rehabilitation training.Results The position vectorgram of the healthy subjects showed anterior-posterior sway and the patients showed right-left or diagonal sway.The patients exhibited much longer value in position vector than healthy subjects(P<0.01).After rehabilitation training,10 patients showed the changes in position vector at six directions,and there was a significant difference compared with those before rehabilitation training(P<0.01).Conclusion The position vector is clinically valuable in balance evaluation and monitoring the effect of treatment.

Objective: To study the factors effecting the expression of the reporter green fluorescent protein (GFP) gene in the mouse embryo stem cell line R1. Methods: Three different kinds of GFP euko-expression vectors were constructed, and the expression efficiency was contrasted both at mRNA and protein levels after they were integrated into the chromosomes of host cells. Results: At protein level, the GFP expression level of the colonies transfected by the expression vector-pEF-GFP with the promoter of the peptide elongation factor (EF) were significantly higher than that of the colonies transfected by pCMV-GFP with CMV promoter and by pdCMV-GFP with double copies of CMV-GFP expression unit. There was no significant difference between the colonies transfected by pCMV-GFP and pdCMV-GFP. The detection results on mRNA level of GFP had the same tendency as that at protein level. Conclusion: (1) GFP gene expression efficiency controlled by EF promoter is distinctly higher than that by CMV promoter in NIH3T3 and R1 ES cell line.(2) A slight increase of the copy number of the foreign gene expression units in the host chromosome can not make obvious increase of its expression efficiency. (3) The vector express GFP in R1 ES cell line efficiently and stablely is obtained.

Objective: To study the factors effecting the expression of the reporter green fluorescent protein (GFP) gene in the mouse embryo stem cell line R1. Methods: Three different kinds of GFP euko-expression vectors were constructed, and the expression efficiency was contrasted both at mRNA and protein levels after they were integrated into the chromosomes of host cells. Results: At protein level, the GFP expression level of the colonies transfected by the expression vector-pEF-GFP with the promoter of the peptide elongation factor (EF) were significantly higher than that of the colonies transfected by pCMV-GFP with CMV promoter and by pdCMV-GFP with double copies of CMV-GFP expression unit. There was no significant difference between the colonies transfected by pCMV-GFP and pdCMV-GFP. The detection results on mRNA level of GFP had the same tendency as that at protein level. Conclusion: (1) GFP gene expression efficiency controlled by EF promoter is distinctly higher than that by CMV promoter in NIH3T3 and R1 ES cell line.(2) A slight increase of the copy number of the foreign gene expression units in the host chromosome can not make obvious increase of its expression efficiency. (3) The vector express GFP in R1 ES cell line efficiently and stablely is obtained.

Objective To prepare the 99Tcm-survivin mRNA antisense peptide nucleic acid (PNA)and investigate its value as a gene imaging agent in tumor bearing mice and early diagnosis in tumor.Methods Survivin mRNA antisense PNA and mismatch PNA were synthesized.Four amino acids (Gly- (D)Ala-Gly-Gly) and Aba (4-aminobutyric acid) were linked to the 5' end of PNA.Gly- (D)Ala-Gly-Gly served as a chelating moiety for strong chelation of 99Tcm and Aba acted as a spacer to minimize the steric hindrance.PNAs were labeled with 99Tcm by the ligand-exchange method.The labeling efficiency and radiochemical purity were measured by HPLC and ITLC methods.There were five BALB/c nude mice bearing human lung carcinoma ( A549 ) in each of antisense PNA and mismatch PNA groups.Gene imaging of 99Tcm-survivin mRNA antisense and mismatch PNAs were performed at 1,2 and 4 h post the injection,respectively,and the T/NT ratio was measured by the method of ROI.The statistical comparisons of average values were performed with the two-group t-test for independent sample by SPSS 13.0.Results The product kept stable in vitro.The labeling efficiency of 99Tcm-survivin mRNA antisense PNA was (95.48 ±1.92)％ and more than 85％ after the incubation for24 h in serum.The radiochemical purity was ＞ 95％.The labeling efficiency of mismatch PNA was similar to the antisense PNA.99Tcm-survivin mRNA antisense PNA was especially uptaken by tumor lesion,and its accumulation reached the top at 4 h post the injection.T/NT ratios at 1,2,and 4 h were 2.70 ± 0.28,3.44 ± 0.35,4.21 ± 0.63,respectively.In the comparison,the T/NT ratio of 99Tcm-survivin mRNA mismatch PNA at 4 h (3.12 ±0.50) was significantly lower (t =2.918,P =0.019).Conclusions 99Tcm-survivin mRNA antisense PNA has high labeling efficiency,good stability and no need of purification.Its characteristic of especial uptake by tumor lesion provides the potential value in early diagnosis of tumor.

Case recruitment of large-scale clinical trials should be strictly checked in quality and quantity for it is the key to clinical trial. This study discusses the main difficulties and countermeasures in the case recruitment of large sample, multi-center clinical trials according to the national research project "Myocardial Infarction Secondary Prevention Study in Traditional Chinese Medicine".

OBJECTIVETo investigate the distribution of tetracycline-arginine-glycine-aspartate-tyrosine (T-RGDY) in mice and its effect on bone.

METHODS125-labeled T-RGDY was studied for its distribution in mice and for its effects on bone by histomorphometry in ovariectomized rats.

RESULTSThe 125I-labeled T-RGDY was more concentrated in the osteoporotic bone than in the normal bone. Compared with ovariectomy group, the morphologic index such as trabecular bone volume/total tissue volume (TBV/TTV), TBV/sponge bone volume (SBV), and mean trabecular plate thickness (MTPT) in T-RGDY group significantly increased (P < 0.05). As compared with sham operation group, MTPT significantly increased in T-RGDY group (P < 0.05), while TBV/SBV and mean trabecular plate density significantly decreased (P < 0.05), and TBV/TYV and mean trabecular plate spacing were almost the same as those in sham operation group (P > 0.05).

CONCLUSIONT-RGDY may concentrate in bone tissue to a certain degree, which is closely related with the status of bone remodeling. T-RGDY may inhibit the bone loss caused by ovariectomy.

Animals ; Bone Density ; drug effects ; Bone Remodeling ; drug effects ; Female ; Mice ; Oligopeptides ; pharmacokinetics ; pharmacology ; Osteoporosis ; metabolism ; prevention & control ; Ovariectomy ; Rats ; Rats, Sprague-Dawley ; Tetracycline ; pharmacokinetics ; pharmacology ; Tissue Distribution ; Tyrosine ; pharmacokinetics ; pharmacology

Humans ; Liver Failure ; therapy ; Liver, Artificial ; adverse effects ; Renal Dialysis ; adverse effects ; Sorption Detoxification ; adverse effects

Orthotopic liver transplantation has proven to be effective in the treatment of a variety of life-threatening liver diseases, however, the limitations of donated organs available and long-term immunosuppression provided an impetus for developing alternative therapies. Cell replacement strategies have been one major effective approach for overcoming the obstacles of organ transplantation in recent years. The exogenous cells should be able to proliferate and differentiate into mature hepatic cells after grafting. Use of mature hepatocytes is also hampered by limited tissue source and inability to proliferate and maintain the function for a long term in vitro. Embryonic stem cells are immortal and pluripotent and may provide a novel cell source for potential cell therapy. This review summarizes the mechanisms of controlling early liver development and hepatic differentiation of visceral endoderm in embryoid bodies, and provides an overview of diverse differentiation systems in vitro and in vivo that were applied to hepatic research in recent years. Several studies have demonstrated that ES cell-derived hepatocytes can incorporate into liver tissue and function in vivo , but a few of them have shown complete restoration of liver function after transplantation into mice with liver diseases. Further studies should be made to exploit efficient methods and clinical applications of hepatocytes derived from ES cells in the future. In addition to clinical transplantation for treatment of liver diseases, ES cells can provide a valuable tool for drug discovery applications and study on of molecular basis of hepatic differentiation.
Animals ; Cell Differentiation ; physiology ; Cells, Cultured ; Embryonic Stem Cells ; cytology ; transplantation ; Hepatocytes ; cytology ; Humans ; Liver Diseases ; therapy

OBJECTIVETo investigate the enhancing effect of Chinese medicine-Xuebijing injection on lipopolysaccharide (LPS) -induced apoptosis of CD4+ CD25+ regulatory T cells (Tregs) and polarization of helper T cells (Th).

METHODSCD4+ CD25+ Tregs collected from rat spleen in vitro by immunomagnetic beads assay were divided into the control group, anti-CD3/CD28 group, anti-CD3/CD28 + LPS group, anti-CD3/CD28 + "Xuebijing injection" group and anti-CD3/CD28 + LPS + "Xuebijing injection" group. Tregs apoptosis rate and expression of winged helix transcription factor (Foxp3) in Tregs were detected by flow cytometry on 3rd post culture day. CD4+ CD25- T cells were co-cultured with CD4+ CD25- Tregs (1:1) for 68 hours with canavalin A stimulation. Interferon gamma (gamma-IFN), interleukin (IL)-4 and IL-17 in supernatants, which respectively was secreted by Th1, Th2 and Th17, were measured by ELISA.

RESULTSTregs apoptosis rate of anti-CD3/CD28 + LPS + "Xuebijing injection" group (45.1 +/- 2.7%) was significantly higher than that of anti-CD3/CD28 + LPS group (29.4 +/- 1.6%, P < 0.01). Meanwhile, Foxp3 expressions in Tregs in above 2 groups were 95 +/- 9 and 140 +/- 18 respectively, showing statistically significant difference between them (P < 0.01). Gamma-IFN levels secreted in anti-CD3/CD28 + LPS + "Xuebijing injection" group were significantly higher than those in anti-CD3/CD28 + LPS group (P < 0.01), while IL-4 levels had an opposite tendency compared with gamma-IFN (P < 0.05), resulting in a marked increase in the ra- tio of gamma-IFN/IL-4 in anti-CD3/CD28 + LPS + "Xuebijing injection" group (P < 0.01). In anti-CD3/ CD28 + "Xuebijing injection" group, IL-17 secretion levels were significantly decreased compared with anti-CD3/CD28 group (P < 0.05).

CONCLUSIONSActivation of CD4+ CD25+ Tregs induced by LPS may mediate Th1 shift to Th2 response. "Xuebijing injection" can effectively regulate immune function of T cells, increase the LPS-induced apoptosis of CD4+ CD25+ Tregs as well as enhance the polarization of Th2 to Th1, thereby abating the suppressive state of cell-mediated immunity.

Animals ; Apoptosis ; Drugs, Chinese Herbal ; pharmacology ; Endotoxins ; Lipopolysaccharides ; Male ; Rats ; Rats, Wistar ; T-Lymphocytes, Helper-Inducer ; drug effects ; immunology ; T-Lymphocytes, Regulatory ; drug effects ; immunology