一种红细胞光散射模型的研究

针对球形细胞模型理论与双凹圆盘状的红细胞在实际光散射法检测中的差异,根据细胞的类别特征,提出以扁椭球模型来模拟红细胞,以Rayleigh-Debye-Gans近似理论为基础,引入扁椭球的体极化率,得到了扁椭球模型的散射光公式,并进行数值模拟,研究其光散射特性。结果表明,扁椭球模型更精确地反映了红细胞光散射的真实情况,同时其前向、侧向及后向光散射精细谱的呈现,可以较容易地辨别病理状态的红细胞,能够较好地提高医学检验及诊断的精度,并可以应用于对红细胞的变形性研究。

椭球模型的夫琅和费衍射的研究

基于夫琅和费衍射理论,应用MATLAB软件进行模拟,对不同形体因子的标准椭球模型进行讨论,并与实验结果进行比较,证实了对于真实微粒测量模型,椭球模型比球模型更具优越性,能够更准确地获得非球形微粒的粒度分布。并从椭球模型的衍射图像反演得到微粒的形体因子。

Identification of anrF gene, a homology of admM of andrimid biosynthetic gene cluster related to the antagonistic activity of Enterobacter cloacae B8

AIM： To identify the gene （s） related to the antagonistic activity of Enterobacter cloacae B8 and to elucidate its antagonistic mechanism. METHODS： Transposon-mediated mutagenesis and tagging method and cassette PCR-based chromosomal walking method were adopted to isolate the mutant strain （s） of B8 that lost the antagonistic activity and to clone DNA fragments around Tn5 insertion site. Sequence compiling and open reading frame （ORF） finding were done with DNAStar program and homologous sequence and conserved domain searches were performed with BlastN or BlastP programs at www.ncbi.nlm.nih.gov. To verify the gene involved in the antagonistic activity, complementation of a full-length clone of the anrFgene to the mutant B8F strain was used. RESULTS： A 3 321 bp contig around the Tn5 insertion site was obtained and an ORF of 2 634 bp in length designated as anrFgene encoding for a 877 aa polyketide synthase-like protein was identified. It had a homology of 83% at the nucleotide level and 79% ID/87% SIM at the protein level, to the admM gene of Pantoea agglomerans andrimid biosynthetic gene cluster （AY192157）. The Tn5 was inserted at 2 420 bp of the gene corresponding to the COG3319 （the thioesterase domain of type I polyketide synthase） coding region on BSF. The antagonistic activity against Xanthomonas oryzae pv. oryzae was resumed with complementation of the full-length anrFgene to the mutant B8F. CONCLUSION： The anrFgene obtained is related to the antagonistic activity of BS, and the antagonistic substances produced by B8 are andrimid and/or its analogs.

Effects of endostatin on expression of vascular endothelial growth factor and its receptors and neovascularization in colonic carcinoma implanted in nude mice

AIM:To investigate the antiangiogenic effects of endostatin on colonic carcinoma cell line implanted in nude mice and its mechanism. METHODS:Nude mice underwent subcutaneous injection with LS-174t colonic carcinoma cell line to generate carcinoma and were randomly separated into two groups.Mice received injection of vehicle or endostatin every day for two weeks. After the tumor was harvested,the tumor volumes were determined,and the expressions of CD34,VEGF and FIk-1 were examined by immunohistochemical method. RESULTS:Tumor volume was significantly inhibited in the endostatin group(84.17%)and tumor weight was significantly inhibited in the endostatin group(0.197±0.049) compared to the control group(1.198±0.105)(F=22.56, P=0.001),microvessel density(MVD)was significantly decreased in the treated group(31.857±3.515)compared to the control group(100.143±4.290)(F=151.62,P<0.001). Furthermore,the expression of FIk-1 was significantly inhibited in the treated group(34.29%) ompared to the control group(8.57%)(X^2=13.745,P=0.001).However no significant decrease was observed in the expression of vascular endothelial growth factor(VEGF)between these two groups(X^2=0.119,P=0.730). CONCLUSION:Endostatin can inhibit tumor growth and angiogenesis by blocking Vegf/FIk-1 pathway.This experiment provides the theory basis for developing a new anti-carcinoma drug through studying the properties of anti-angiogenesis inhibitors.

Pituitary prolactin adenoma with Toxoplasma gondii infection

Objective: To report two recent cases of pituitary adenoma associated with Toxoplasma gondii (T.Gondii) infection.Methods: Histological changes were observed in H & E and PAS staining sections microscopically.Immunohistochemistry was performed to classify the pituitary tumors and to confirm the diagnosis of T.gondii.Results: The cases were 43- and 19-year-old females, in which the latter one was a recurring case, and radiology examination showed that tumors existed in sellar region.Microscopically, the tumors consisted of small homogenous polygonal or round cells with abundant eosinophilic granular cytoplasm.Immunohistochemistry revealed they were prolactin-producing adenomas.Interestingly, we found toxoplasma infection in the tumor tissues, being confirmed by T.gondii sepicific antibody immunohistochemistry.Conclusion: The association of pituitary adenoma with toxoplasma raises the possibility that T.gondii may be involved in the development of certain cases of pituitary adenoma.

Vertical Crustal Displacements Due to Surface Fluid Changes

Using the model data for surface mass changes of the atmosphere, ocean, soil moisture and snow depth, the vertical crustal displacements of 25 ficual stations in China were calculated according to the loading theory. From the spectral analysis of the results, we can see that the periods of displacements are 12 months and the semi-periods are 6 months. The results also show that the maximum seasonal displacements can reach 20 mm and even larger. The covariance analyses and significance tests show that the coefficients of 96 percent of the stations are significant at the 0.1 significance level. The results show that one of the reasons of the vertical crustal displacements is the changing surface fluid loads.

Role of yttrium content in twinning behavior of extruded Mg−Y sheets under tension/compression

The influence of Y content on the grain-scale twinning behavior in extruded Mg−xY(x=0.5,1,5,wt.%)sheets under uniaxial tension and compression along the extruded direction was statistically investigated.An automatic twin variant analysis was employed,based on large data sets obtained by electron backscatter diffraction(EBSD),including 2691 grains with 977 twins.The{1012}tension twinning(TTW)dominance and prevailing anomalous twinning behavior(Schmid factor(m)<0)under both tension and compression were found.The anomalous twinning behavior was more pronounced as Y content increased under tensile loading,indicating a promoted stochasticity of twin variant selection for more concentrated Mg−Y alloys.However,the trend for the Y-content dependent anomalous twinning behavior was opposite in compression.The fractions of the anomalous TTWs were found to be well correlated with the maximum Schmid factor(m_(max))values of basal slip and prismatic slip in the corresponding parent grains for compression and tension,respectively,indicating that twinning and dislocation slip might be closely related in the present Mg−Y alloys.

有核细胞的弹性光散射模型

提出一种新型的同心椭球构成的同心椭球(CEM)模型来模拟有核细胞,以瑞利德拜甘斯(Rayleigh-Debye-Gans)近似理论为基础,对细胞内不同部分的传播常量加以修正,用该模型代替球系列模型,研究其光散射特性。结果表明同心椭球模型更精确地反映了非球形有核细胞光散射的真实情况,同时其前向、侧向及后向光散射精细谱的呈现,可以在庞杂的细胞中辨别不同的细胞类型,较好的应用于细胞的变形性研究和细胞分类研究的领域。