3种不同焦油卷烟烟气的细胞毒性比较

采用中性红法测定了K2R4F参比卷烟和15、8和3mg/支焦油市售国产混合型卷烟烟气的细胞毒性。即卷烟主流烟气经洁净空气稀释后直接导入BALB/c3T3细胞培养瓶中染毒,而后采用中性红法测定细胞毒性,并计算出基于烟气总粒相物的相对细胞死亡率和LC50。结果表明:4种卷烟的细胞毒性依次为15mg/支焦油卷烟>>8mg/支焦油卷烟≈K2R4F>3mg/支焦油卷烟,与这3种国产卷烟样品烟气气相自由基、烟草特有N-亚硝胺和稠环芳烃的降低一致。说明卷烟减害降焦,可以降低其烟气的细胞毒性,降低吸烟对健康的危害。     

THE ROLE OF STATISTICS IN PRODUCT QUALITY — SOME EXAMPLES1

The practice of thinking statistically has become more common in recent years. Rising costs, increased “consumerism” and advanced technology have stimulated more interest in probability-based decision making. Two examples of recent advances in statistical quality control technology are presented.     

Comparative atomic force and scanning electron microscopy: an investigation on fenestrated endothelial cells in vitro

Rat liver sinusoidal endothelial cells (LEC) contain fenestrae, which are clustered in sieve plates. Fenestrae control the exchange of fluids, solutes and particles between the sinusoidal blood and the space of Disse, which at its back side is flanked by the microvillous surface of the parenchymal cells. The surface of LEC can optimally be imaged by scanning electron microscopy (SEM), and SEM images can be used to study dynamic changes in fenestrae by comparing fixed specimens subjected to different experimental conditions. Unfortunately, the SEM allows only investigation of fixed, dried and coated specimens. Recently, the use of atomic force microscopy (AFM) was introduced for analysing the cell surface, independent of complicated preparation techniques. We used the AFM for the investigation of cultured LEC surfaces and the study of morphological changes of fenestrae. SEM served as a conventional reference.
AFM images of LEC show structures that correlate well with SEM images. Dried-coated, dried-uncoated and wet-fixed LEC show a central bulging nucleus and flat fenestrated cellular processes. It was also possible to obtain height information which is not available in SEM. After treatment with ethanol or serotonin the diameters of fenestrae increased (+6%) and decreased (−15%), respectively. The same alterations of fenestrae could be distinguished by measuring AFM images of dried-coated, dried-uncoated and wet-fixed LEC. Comparison of dried-coated (SEM) and wet-fixed (AFM) fenestrae indicated a mean shrinkage of 20% in SEM preparations. In conclusion, high-resolution imaging with AFM of the cell surface of cultured LEC can be performed on dried-coated, dried-uncoated and wet-fixed LEC, which was hitherto only possible with fixed, dried and coated preparations in SEM and transmission electron microscopy (TEM).