Recombinant human stem cell factor stimulates growth of a human glioblastoma cell line expressing c-kit protooncogene.

The growth of a panel of eight different human glioblastoma cell lines was examined in a human tumor cloning assay in agar, a tritiated thymidine uptake assay, and by counting cell numbers, in cultures performed in the absence or presence of increasing concentrations (1 to 100 ng/ml) of recombinant human stem cell factor (SCF). Growth of 7 of 8 cell lines was not significantly and reproducibly affected by recombinant human SCF. However, growth of the CRL 1620 cell line could be stimulated up to 5-fold by the cytokine. In contrast to the other cell lines investigated, CRL 1620 expressed the c-kit protooncogene assessed on the mRNA and protein level. Furthermore, SCF-induced proliferation of CRL 1620 cells was sensitive to the tyrosine kinase inhibitor erbstatin. Our data suggest that SCF can be operative in growth modulation of malignant cells outside the hematopoietic system, and this finding should be further studied for its possible clinical implications.     

烧伤大鼠血清对血管内皮细胞通透性的影响

加深入阐明严重烧伤早期全身血管通透性增加继而引直民早期损害的发生机制，本实验应用培养于微孔滤膜上的小牛瞌 及皮细胞单层所构成的选择性通透屏障模型，观察了３０％Ⅲ度烧伤大鼠血清对其影响，结果发现，烧伤早期烧伤血清刺激后ＥＣ单层对Ｈａｎｋｓ液或白蛋白液滤过流量、滤过系数均明显增加。     

医用电子产品的电气安全检测

医用电子技术在不断变化，为提高检测过程的工作效率．医用电子产品的电气安全检测技术也在相应发展．发展的总方向离不开检测综合化和自动化。     

Comparison of fMRI statistical software packages and strategies for analysis of images containing random and stimulus-correlated motion.

The objectives of this study were to use computer-generated phantoms containing real subject motion to: (1) compare the sensitivity of four commonly used fMRI software packages and (2) compare the sensitivity of three statistical analysis strategies with respect to motion correction. The results suggest that all four packages perform similarly in fMRI statistical analysis with SPM2 having slightly higher sensitivity. The most sensitive analysis technique was to perform motion correction and include the realignment parameters as regressors in the general linear model. This approach applies to all four packages examined and can be most beneficial when stimulus-correlated motion is present.     

Innervation of the trapezius muscle: is cervical contribution important to its function?

OBJECTIVE: To study the effect of the cervical plexus and the accessory nerve to the function of the trapezius muscle. STUDY DESIGN AND SETTING: Eighteen adult male Sprague-Dawley rats were randomly divided into three groups. The neurotomies were performed in the left sides and the right sides served as within-subject controls. In group A, the accessory nerve was transected. The C2-5 were transected in group B, and both of the accessory nerve and C2-5 were cut in group C. The electrophysiologic, myophysiologic, and histologic changes of the muscles were measured. RESULTS: There were significant differences (P < 0.05) between the three groups in the recovery rates of the transverse area of the muscles. The CMAP recorded from the experimental sides in group B were similar to the control sides. The values of the maximum tension of the tetanus contraction between the two sides showed no differences either (P > 0.05). CONCLUSION: The accessory nerve supplies the most important motor input to the trapezius. Motor innervations of the cervical plexus are not very significant.     

头孢噻肟钠聚合物测定实验条件的改进

目的:对中国药典收载的头孢噻肟钠聚合物测定条件进行改进。 方法 :采用高效液相色谱法 ,以Sephadex G- 10色谱柱 4 2 cm× 1.3cm对 6批样品进行分析 ,分别进样 5 0μl和 2 0 0μl,按外标法计算聚合物的量。结果:头孢噻肟钠在 10～ 6 0 μg/m l范围内线性关系良好 (r=0 .9995 ) ,高中低浓度的加样回收率分别为 10 0 .2 %、10 0 .4 %、99.7% ;RSD分别为 1.7%、1.5 %、1.9% (n =3)。该方法与药典方法比较 ,差异无统计学意义 (P >0 .0 5 )。 结论:本方法简便、快速、可行 ,具有实用价值     

一种新的正交参数选优法及其在非线性回归分析中的应用

非线性回归分析是工程中经常采用的一种用来估计数学模型参数的方法，该方法能否顺利运用与参数初始值的选择有极大关系。本研究提出一种新的正交参数选优法——阻尼正交表法，它不仅可以保证非线性回归分析算法的顺利收敛，而且能够显著提高后者的收敛速度，进而极大改善非线性回归分析算法的应用性能。本研究的数值试验及心肌造影超声心动图定量分析应用实例表明，作为对传统正交参数选优法的一种改进，阻尼正交表法在科学与工程计算或信号与信息处理领域有着很好的应用前景。