应用威布尔分布函数研究红霉素微囊的溶出度

本文测定了红霉素微囊在人工肠液中的溶出度，并用威布尔分布函数求出了溶出百分率与时间的关系。     

MTT法检测极低频弱磁场对SY细胞的影响

本文采用 MTT 示踪法,检测极低频弱磁场对 SY 细胞有无影响。结果发现:频率固定为50Hz 时变化磁场幅值,在150uT、300uT 下细胞吸光度值有明显降低;幅值固定为150uT 时变化磁场频率,在25Hz、50Hz、75Hz 磁场照射下吸光度值均有不同程度下降,而在10Hz、60Hz、100Hz、300Hz、500Hz 磁场照射下没有变化;幅值固定为300uT 时变化磁场频率,在500Hz、75Hz、100Hz、300Hz、磁场照射下吸光度值均有不同程度下降,而在10Hz、25Hz、60Hz、500Hz 磁场照射下没有变化。     

Petal-like apatite formed on the surface of tricalcium phosphate ceramic after soaking in distilled water

In the present study six types of tricalcium phosphate ceramic were prepared and soaked in distilled water for different periods to investigate whether a surface apatite layer was formed on TCP ceramics or not. X-ray diffractometry (XRD) and Fourier-transformed infrared (FTIR) spectrometer were used to examine the changes in crystalline phases and functional groups of TCP ceramics for different soaking periods. Calcium and phosphate ions released from TCP ceramics during soaking were recorded by atomic absorption analysis and ion-coupled plasma. Results revealed that alphaTCP, alphaTCP/betaTCP mixture (alphabetaTCP) and betaTCP ceramic were gradually dissolved. There was no apatite layer formed on their surface after being immersed in distilled water for different durations of time. Mg-TCP ceramic, tricalcium phosphate doped with Mg ions, exhibited a lower dissolution rate than the other types of TCP ceramics. Apatite crystals were also not formed on the surface of Mg-TCP ceramic when immersed in distilled water. Tribasic calcium phosphate, prepared from wet precipitation method, was converted to betaTCP/HAP (HbetaTCP) or alphaTCP/betaTCP/HAP (HalphabetaTCP) crystalline composition at different sintering temperatures (1,150 degrees C and 1,300 degrees C). The surface apatite layer did not appear on HbetaTCP ceramic after soaking. We observed that petal-like apatite was formed on the HalphabetaTCP ceramic surface after being immersed for 2 weeks. alphaTCP phase of HalphabetaTCP ceramic was not directly converted to apatite during soaking. The surface apatite layer formed on the HalphabetaTCP ceramic surface was due to the precipitation of the calcium and phosphate ions released from alphaTCP dissolution. HAP, which existed in the structure of HalphabetaTCP ceramic, plays a role as apatite-precipitating seed to uptake calcium and phosphate ions. TCP ceramics which lacked alphaTCP and HAP content neither converted to apatite nor formed surface apatite on their surfaces during immersion.     

基于人工视网膜神经节细胞感受野的图像边缘检测

用光电池组装一个工感受野，在一维上模拟视网膜神经节细胞的零交叉滤波特性，进一步用该工工感受野构建一个图像边缘检测系统，并成功地用系统检测到图像边缘。一与般的基于视觉原理的图像系统相比，这种以人工感受野灵基础的系统，在图像输入的同时即可并行地提取图像边缘信息，而更接近于动物视觉系统原型，此结果将为人工视觉和图像技术的发展提供新的探索。     

In vitro effects of low-intensity ultrasound stimulation on the bone cells

Mechanical perturbations serve as extracellular signals to a variety of cells, including bone cells. Low-intensity pulsed ultrasound produces significant multifunctional effects that are directly relevant to bone formation and resorption. Ultrasound stimulation has been shown to accelerate bone-defect healing and trabecular bone regeneration. In this study, we use an in vitro bone cell culture model to investigate the effect of low-intensity pulsed ultrasound. The rat alveolar mononuclear cell-calvaria osteoblast coculture system was used in this study. Before treatment, the bone cells were cultured for 3 days to facilitate their attachment and differentiation. Then, ultrasound exposure (frequency = 1 MHz, intensity = 0.068 W/cm(2)) or sham exposure for 20 min per day was applied until the end of the experiment. Half of the culture media were obtained on the 4th, 5th, 6th, 7th, 8th, 9th, and 10th days for the analysis of cytokines and biochemical parameters. At the end of the experiment, cells were fixed and stained for identification and quantification of the osteoblast and osteoclast cells. After low-intensity pulse ultrasound stimulation, the osteoblast cell counts were significantly increased, whereas the osteoclast cell counts were significantly decreased. The total alkaline phosphatase amount in the culture medium was increased after 7 days of ultrasound stimulation, and tumor necrosis factor-alpha in ultrasound-stimulated bone cells was significantly increased after the 7th day of culture and reached 474.77% of the control medium on the 10th day of culture. The results of this study suggest that low-intensity ultrasound treatment may have a stimulatory effect on bone-healing processes.     

桥粒斑蛋白II在肿瘤组织中的表达

桥粒斑蛋白ＩＩ（ＤＰＩＩ）是一种新的上皮和上皮性肿瘤标记物。我们应用针对石蜡切片的抗ＤＰＩＩ单抗和抗细胞角蛋白（ＣＫ）单抗对２ｌ７例肿瘤作了免疫组织化学ＡＢＣ法染色的研究，结果：在１６３例上皮性肿瘤和双向分化的肿瘤中，１４７例表达ＤＰＩＩ，占９０．７％，９２例表达ＣＫ，占５６．４％。ＣＫ阳性染色全部位于细胞浆内，ＤＰＩＩ阳性染色则同时分布在细胞交界面上和细胞浆中。其他５４例不含桥粒的肿瘤均无ＤＰＩＩ和ＣＫ表达。结果表明，ＤＰＩＩ单抗是有用的含桥粒肿瘤的免疫组化探针。因ＤＰＩＩ不存在于一切含桥粒肿瘤，故在鉴别上皮性肿瘤时，ＤＰＩＩ单抗尚需与其他上皮标记物的抗体合并使用。     

The C. elegans microRNA let-7 binds to imperfect let-7 complementary sites from the lin-41 3'UTR

Caenorhabditis elegans let-7, a founding member of the microRNA family, is predicted to bind to six sites in the 3'UTR of the mRNA of its target gene, lin-41, to down-regulate LIN-41. Here, we demonstrate that wild-type let-7 microRNA binds in vitro to RNA from the lin-41 3'UTR. This interaction is dependent on two conserved let-7 complementary sites (LCSs). A 27-nucleotide sequence between the LCSs is also necessary for down-regulation in vivo. LCS mutations compensatory to the lesion in let-7(n2853) can partially restore lin-41 3'UTR function in a let-7(n2853) background, providing the first experimental evidence for an animal miRNA binding directly to its validated target in vivo.     

Pregnancy-associated plasma proteins in pregnant and pseudopregnant rats.

As in the human, the rat pregnancy-associated plasma proteins consisted of four distinct entities as revealed by immunological methods. All showed gradual increases during gestation and rapid disappearance postpartum. They could be physicochemically, although not immunologically, tentatively related to the human pregnancy proteins. None of them was detectable in the serum of rats at various stages of pseudopregnancy, nor in nonpregnant rats.     

非霍奇金淋巴瘤与p53蛋白表达的关系

目的 :探讨非霍奇金淋巴瘤 (NHL)与 p5 3蛋白表达的关系。 方法 :用免疫组化S P法检测 10 2例 (低度恶性 2 3例 ,中度恶性 36例 ,高度恶性 4 3例 )NHLp5 3蛋白表达 ,根据 p5 3蛋白阳性细胞百分率将其表达水平分为 4级 :0级 (阴性 ) ,1级 (1%～ 2 5 % ) ,2级 (2 6 %～ 5 0 % ) ,3级 (>5 0 % )。结果 :低度恶性组 2 0 / 2 3(87% )p5 3表达为 0级 ,中度恶性组 31/ 36 (86 1% )表达为 1级 ,高度恶性组 33/ 4 3(76 7% )表达为 2～ 3级。 2 5例随访 7～ 6 8个月 ,p5 30～ 1级NHL完全缓解率 (CRR ,11/ 14 )高于p5 32～ 3级NHLCRR (1/ 11,P <0 0 1) ,前者生存率 (13/ 14 )高于后者 (3/ 11,P <0 0 1)。NHLp5 3蛋白表达水平与其恶性度密切相关 (P <0 0 1)。结论 :p5 3蛋白表达阳性细胞百分率是判断NHL恶性度、疗效及预后较可靠的参数。肿瘤性p5 3蛋白表达检测对中高度恶性NHL的诊断有参考价值