Peptidomic analysis of rat urine using capillary electrophoresis coupled to mass spectrometry

We have established and validated a protocol for the peptidomic analysis of rat urine using CE coupled to MS (CE-MS). In the first experiments, the reproducibility of the CE-MS set-up and of the established preparation procedure were assessed. To establish a first rat urinary peptidome map, samples were also analyzed using CE-FT-ICR. The subsequent analysis of independent samples from two different strains (WISTAR and CD) indicated strain-specific differences, which were validated in a blinded assessment. MS/MS revealed the presence of specific fragments from well-known urinary rat peptides, such as collagens, alpha-1-antitrypsin, and serum albumin. The CE-MS-based peptidomics platform may provide novel insights into body fluids of animal models, such as rat or mice. Together with peptide identification, the technology appears to be an excellent, complimentary, and non-invasive tool to analyze toxicological or other (patho)physiological effects of pharmaceutical compounds in animal models.     

脉冲电磁波对大鼠甲状腺形态及功能的影响

研究脉冲电磁波（Pulsed electromagnetic wave,PEMW）对大鼠甲状腺形态及功能的影响。雄性SD（Sparague—dawley rats,多雷大鼠）大鼠固定于场强为115kVm^-1的脉冲电磁场中进行1．2万次脉冲的全身辐照,分别于辐照后24、48、96、192h采血、分离血清、应用放射免疫分析方法（Radioimmunoassay,RIA）测定大鼠血清中促甲状腺激素（Thyroid-stimulating hormone,TSH）、甲状腺素（Thyroxine,T4）及三碘甲腺原氨酸（Triiodo—thyronine,T3）的含量;同时取甲状腺,制作常规光镜、电镜标本,分别在光学显微镜和透射电子显微镜下观察甲状腺形态的变化。脉冲电磁波辐照后24h,大鼠血清T3、T4、TSH均迅速上升至最高点,其中T4、TSH与假辐照组比较均有显著性差异（p〈0．01）;随后激素含量逐渐降低,并呈波动性变化。光镜下,各辐照组大鼠甲状腺组织结构未见明显改变;在电子显微镜下,脉冲电磁波辐照后12h大鼠甲状腺滤泡上皮细胞即出现超微结构改变,至48h呈逐渐加重趋势,主要表现为内质网明显扩张、大量蛋白分泌物聚集,脂滴出现,核异染色质的边集等;至照后96h损伤减轻,但尚未完全恢复正常。脉冲电磁波辐照可引起大鼠血清中TSH、T3、T4含量变化和甲状腺超微结构的损伤性改变,其超微结构的损伤主要累及粗面内质网。     

HEAT TRANSFER FROM A HORIZONTAL BUBBLING SURFACE TO AN OVERLYING WATER POOL†

An experimenl was performed to study the effects of bubbling from a circular, horizontal, fiat plate on the heat transfer to an overlying water pool. The plate had drilled orifices through which nitrogen was injected into an overlying pool of water at atmospheric pressure. For “deep” pools, the heat transfer coefficient was found to increase only about 20% over a range of superficial gas velocities from 0.6 to 8.5cm/s, A turbulent heat transfer model developed by Konsetov was found to agree well with the data from this experiment. This model and the experimental data suggest that under certain conditions the heat transfer coefficient is similar for both horizontal and vertical surfaces. These conditions are, that the bubbles only contribute to the stirring action in the pool and only when the bubbling pool is considered “deep”. When the pool height fell below 60% of its diameter, the heat transfer coefficient decreased almost linearly with pool height. This suggests that there occurs a reduction in the turbulent fluctuations or in the characteristic length scale based on the average turbulent eddy size as the pool height decreases.     

Bioadhesive characteristics of chitosan microspheres to the mucosa of rat small intestine

Chitosan (Chi) microspheres were examined in vitro and in vivo in terms of their bioadhesive characteristics to the mucosa of rat small intestine. Chi was labeled with fluorescein isothiocyanate (FITC), and the microspheres (FTC-MS) were prepared by the dry-in-oil method using the obtained fluorescein thiocarbamyl-chitosan (FTC-Chi). FTC-MS with a mean diameter of 27 μm and size distribution of a few micrometers to several tens of micrometers was used for the bioadhesion experiment. FTC-MS exhibited a tendency to adhere to each part of the small intestine to a greater extent than dissolved FTC-Chi, and the ratio of adhering FTC-MS increased as the amount of added FTC-MS decreased. FTC-MS showed slower transit following intraduodenal injection than oral administration. Following the intraduodenal injection of FTC-MS, more than half remained in the upper or middle part of the small intestine for over 8 h. Further, insulin-containing chitosan microspheres with a mean diameter of 20 μm and size distribution of 5 μm to 45 μm were checked in situ for drug absorption, but intraduodenal or intraileal application hardly gave any decrease in plasma glucose level at a very high dose. The present chitosan microsphere system showed good adhesion to the intestinal mucosa, but scarcely facilitated absorption of insulin.     

茶多酚降低卷烟烟气毒性的研究

卷烟烟气会导致鼠肺细胞膜脂质过氧化损伤。采用适当的方法将茶多酚添加到卷烟中,能有效地抑制烟气引发的鼠肺细胞膜脂质过氧化水平,抑制率可达30％－40％,抑制效果优于维生素C和维生素E,且抑制作用的稳定性较好,实验还证明了把纳米SiO2与茶多酚溶液经超声波处理后再添加到卷烟中,其抑制烟气对鼠肺细胞膜脂质过氧化损伤效果更佳。     

Cytotoxicity of titanium dioxide nanoparticles differs in four liver cells from human and rat

Titanium dioxide (TiO₂) nanoparticles (NPs) are the important nanoscale components of composites. Although TiO₂ NPs and their related nanocomposites have been widely used in industrial and medical applications, the adverse effects of TiO₂ nanomaterials have not been well studied. Here, we investigated the cytotoxicity of TiO₂ NPs in vitro using four liver cell lines: human hepatocellular carcinoma cell line (SMMC-7721), human liver cell line (HL-7702), rat hepatocarcinoma cell line (CBRH-7919) and rat liver cell line (BRL-3A). We checked cell viability, cell morphology, and the levels of reactive oxygen species (ROS) and glutathione (GSH) after TiO₂ exposure at varying concentrations (0.1–100 μg/mL) and different exposure periods of time (12–48 h). Compared to the NP-free control, all four cell lines exposed to TiO₂ NPs showed cytotoxicity in a dosage-dependent and time-dependent manner, which was associated with the changes of cell viability and cell morphology, increased intercellular ROS levels, and decreased intracellular GSH levels. Further, we observed that carcinomatous liver cells and human liver cells exhibited more tolerance to TiO₂ NPs exposure for 24 h, compared to normal liver cells and rat liver cells, respectively. The results indicate that the in vitro cytotoxicity induced by NPs should be assessed with great caution before the use of nanocomposites and that there is a need to standardize the cytotoxicity testing procedure of nanoscale components in composites when using different cell lines.     

强化铁,锌食盐对大鼠生长发育的影响

采用强化铁，锌食盐喂养缺铁，缺锌大鼠４周后，大鼠血红蛋白和血清锌明显增高，补强化食化组大鼠体重增长也明显高于对照组。