TCA-100 tumour chemosensitivity assay: differences in sensitivity between cultured tumour cell lines and clinical studies

The BATLE LE TCA-100 tumour chemosensitivity assay has been used to evaluate chemotherapeutic drug sensitivity of cultured tumour cell lines. Studies were performed using test drug concentrations calibrated to discriminate sensitivity and resistance of clinical specimens. Strong sensitivity which appeared to be inconsistent with clinical experience was detected for some drugs and cell lines. Findings of strong sensitivity were consistent with basic differences between sensitivity testing cultured cell lines and clinical specimens. Results with cell lines frequently may not apply directly to clinical applications. Characterization of differences between cell lines and clinical specimens may assist in application of cell line findings to clinical trials.     

车辆碰撞检测的一种简化数学模型

该文建立了车辆碰撞检测的一种简化数学模型,并进行了仿真验证。实际应用结果表明本模型具有简单和计算快捷的特点,能满足车辆碰撞检测的仿真要求。     

Effect of mutagens on RNA-containing phages and its infectious RNA. VII. Genetic nature of morphologic mutants of RNA-containing phage MS2

Temperature-sensitive "leaky" mutants of phage MS2 having white dense ring around negative colonies are described. As these mutants are used for quantitative genetic studies, the white ring presents interest. Typical mutant 40 is used as a model for investigation. Light microscopy has shown, that cells from white ring zone have spore-like inclusions, which determine the characteristic structure of surrounding mutant negative colonies. Cytochemical reactions for the presence of glicogen, lipids, volutin, nuclear material and spores were negative. Electrone microscopy of negatively stained samples and ultrathin sections has revealed that cells from white ring zone, unlike phage-infected wild type cells, have two types of electron dense inclusions: 1) crystalline structures formed with great number of closely packed mature phage particles, and 2) large amorphic bodies. Electrone microscope-cytochemical data showed that inclusions remain intact under treatment of ultrathin sections of white zone ring with DNase and perchloric acid, while nuclear material was completely destroyed. Amorphic bodied were completely destructed after the treatment with RNase, while nuclear material and crystalline phage aggregated remained unchanged. Therefore, amorphic bodies consist of RNA, which has not been used to form virions. Single cycle of the development of mutant 40 at 37 degrees and 43 degrees C and under the temperature of incubation 37 degrees leads to 43 degrees C and 43 degrees leads to 37 degrees C in the course of intracellular reproduction is investigated. Influence of the phage on growth on infected culture is studied. The data obtained draw to a conclusion that the impaired function belongs to cystron protein of the phage membrane. As certain mutations in this cystrone of RNA-containing phage result in the depression of cystrone RNA polymerase, it is supposed that the formation of RNA containing bodies in infected cells, determining the formation of white rings in NA, together with cristalline aggregates of cells, is a result of mutation damage of cystrone protein of the phage MS2 membrane.     

Low-affinity NGF-receptor and E-N-CAM expression define two types of olfactory nerve ensheathing cells that share a common lineage

Previously, we have shown that the O4 antibody can be used to define and purify olfactory nerve ensheathing cells (ONECs) from the rat olfactory bulb by fluorescence-activated cell sorting. In this study, using a larger panel of neural markers, we demonstrate that this apparently homogeneous population of ONECs possess a heterogeneous antigenic profile both in vivo and in vitro. The antigenic profile of the sorted cells initially correlated with their antigenic profile in vivo, although expression of some of the markers was either lost or gained during time in culture. These changes were influenced by the culture conditions, with a greater loss of "typical" ONEC markers in serum-containing medium. In serum-free medium, which maintains the cells in a phenotype that closely resembles their in vivo counterparts, we were able to reclassify the ONECs into two cell types based on morphology and antigenic phenotype by using antibodies to polysialic acid (correlating with the embryonic form of N-CAM expression) and the low-affinity nerve growth factor receptor. A detailed immunocytochemical study of the developing olfactory system showed that these two cell types could also be detected along the entire length of the olfactory nerve and the outer layer of the olfactory bulb from Embryonic Day 14 to adulthood, suggesting they were not an in vitro artefact. To address the relationship between the two cell types we constructed a clonal ONEC cell line by retroviral infection with the temperature-sensitive mutant gene of the large T antigen. This clonal cell line contained cells that expressed antigenic phenotypes of both classes of ONECs, suggesting that both cell types are related and share a common lineage.