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131.
本实验用胆固醇粉喂家兔,造成实验性高脂血症,活体观察球结膜微循环的形态、流态及血管周围状态等15项指标,并用球结膜微循环综合定量评价方法计算了综合积分值。处死后取球结膜进行组织学检查。结果表明:高脂血症家兔球结膜微循环有明显改变,主要为微血管形态异常、血流减慢、红细胞聚集、白微栓、静脉壁上有白色斑块等改变。球结膜微循环综合积分值明显增加,高于实验前。球结膜组织学检查发现上皮层下有泡沫细胞、血管壁增厚、有空泡、静脉内有血栓。虹膜睫状体内除有多数泡沫细胞外,还有胆固醇的菱形结晶。上述改变表明,高脂血症兔球结膜微循环有明显改变。血液有高凝、高聚倾向。黑茶中的茶色素有抗凝、抑制血小板聚集、促进纤溶等作用,口服黑茶可改善高脂血症兔球结膜微循环障碍。 相似文献
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136.
分析了黑松、马尾松及其杂种的核型。其核型公式:黑松为K(2n)=24-20m(6_(SAT)))+4sm;杂种为K(2n)=24=23m+1sm;马尾松为K(2n)=24-24m(4_(SAT))。相对长度和臂比方差分析表明,两亲本和杂种差异显著。杂种在相对长度、全组染色体总长、最长与最短染色体比、臂比平均值以及染色体类型上均处于双亲之间。这些研究结果为进一步研究该天然杂种提供必要的细胞学资料。 相似文献
137.
The dependence of blastocyst development on the extracellular Na+/K+ ratio was investigated in an in vitro system. Hatching and outgrowth of mouse blastocysts was enhanced at Na+/K+ ratios between 3 and 10 compared to the ratio of about 25 typical for most culture media and serum. At a Na+/K+ ratio of 2, blastocyst hatching and outgrowth were inhibited. The requirement of blastocyst development for relatively high extracellular K+ concentrations agrees with the fact that K+ concentrations in oviduct and uterine secretions are higher than in serum. The findings can also be relevant in optimizing in vitro culturing techniques for blastocysts. 相似文献
138.
Y. Li M. M. Bhargava A. Joseph L. Jin E. M. Rosen I. D. Goldberg 《In vitro cellular & developmental biology. Animal》1994,30(2):105-110
Summary Using an automated cell analyzer system, the effect of hepatocyte growth factor/scatter factor (HGF/SF), epidermal growth
factor (EGF), basic fibroblast growth factor (bFGF), endothelial acidic fibroblast growth factor (a-FGF), platelet derived
growth factor (PDGF), and recombinant human insulinlike growth factor (IGF) on the motility and morphology of Madin-Darby
canine kidney (MDCK), rat hepatomas, C2, and H5–6 and murine mammary carcinoma (EMT-6) cells was investigated. Treatment of MDCK cells with HGF/SF, bFGF, EGF, and a-FGF resulted
in an increase in average cell velocity and in the fraction of moving cells. Cells treated with the PDGF and IGF did not show
significant alterations in velocity. MDCK cells treated with each growth factor were classified into groups of “fast” and
“slow” moving cells based on their average velocities, and the average morphologic features of the two groups were quantitated.
Fast-moving cells had larger average area, circularity, and flatness as compared to slow-moving cells. Factors that stimulated
cell movement also induced alterations in cell morphologic parameters including spreading, flatness, area, and circularity.
HGF/SF also scattered and stimulated motility of C2 and H5–6 hepatoma cells. In contrast to MDCK cells, there was no significant difference between the morphology of the fast moving
and slow moving C2 and H5–6 cells. These studies suggest that growth factor cytokines have specific effects on motility of normal and tumor cells. 相似文献
139.
Xin-Min Li† Jin Qi Augusto V. Juorio Alan A. Boulton 《Journal of neurochemistry》1993,61(4):1573-1576
Abstract: Gliosis is commonly observed in the CNS following tissue damage, and it also occurs in aging and in many neurodegen-erative diseases. Glial fibrillary acidic protein (GFAP) accumulation is a prominent feature of astrocytic gliosis. An inhibition or delay in GFAP synthesis could mitigate scar formation and thus reduce the formation of a physical barrier. The consequence of this would be to allow neurons and oligodendrocytes to reestablish a functional environment. (—)-Deprenyl, a specific monoamine oxidase (MAO) B inhibitor, has been used as an effective antipar-kinsonian drug, and it has been reported to possess neuroprotective and neurorescue properties. Using northern and slot blots to detect GFAP mRNA in C6 glioma cells, we have demonstrated that (—)-deprenyl decreases the abundance of GFAP mRNA in a time- and dose-dependent manner. The effect seems to be specific to MA0 B inhibitors because (+)-deprenyl and clorgyline exhibit no effect. This study indicates therefore that (-)-deprenyl may be useful for regulating astrogliosis following CNS injury as well as in some neurodegenerative diseases. 相似文献
140.
Vntr Allele Frequency Distributions under the Stepwise Mutation Model: A Computer Simulation Approach 总被引:10,自引:9,他引:1
Variable numbers of tandem repeats (VNTRs) are a class of highly informative and widely dispersed genetic markers. Despite their wide application in biological science, little is known about their mutational mechanisms or population dynamics. The objective of this work was to investigate four summary measures of VNTR allele frequency distributions: number of alleles, number of modes, range in allele size and heterozygosity, using computer simulations of the one-step stepwise mutation model (SMM). We estimated these measures and their probability distributions for a wide range of mutation rates and compared the simulation results with predictions from analytical formulations of the one-step SMM. The average heterozygosity from the simulations agreed with the analytical expectation under the SMM. The average number of alleles, however, was larger in the simulations than the analytical expectation of the SMM. We then compared our simulation expectations with actual data reported in the literature. We used the sample size and observed heterozygosity to determine the expected value, 5th and 95th percentiles for the other three summary measures, allelic size range, number of modes and number of alleles. The loci analyzed were classified into three groups based on the size of the repeat unit: microsatellites (1-2 base pair (bp) repeat unit), short tandem repeats [(STR) 3-5 bp repeat unit], and minisatellites (15-70 bp repeat unit). In general, STR loci were most similar to the simulation results under the SMM for the three summary measures (number of alleles, number of modes and range in allele size), followed by the microsatellite loci and then by the minisatellite loci, which showed deviations in the direction of the infinite allele model (IAM). Based on these differences, we hypothesize that these three classes of loci are subject to different mutational forces. 相似文献