Dyes as Photoinitiators or Photosensitizers of Polymerization Reactions

A short but up-to-date review on the role of dyes in the photoinitiation processes of polymerization reactions is presented. Radical and cationic reactions are largely encountered in the radiation curing and the imaging areas for use in traditional coating applications as well as in high tech sectors such as nanofabrication, computer-to-plate processing, laser direct imaging, manufacture of optical elements, etc. Recent promising developments concerned with the introduction of the silyl radical chemistry that enhances the polymerization efficiency are also discussed.     

针对组织工程多孔生物陶瓷的组织学技术优化探讨

目的 改进硬组织切片技术以适应生物陶瓷材料在骨组织工程中的研究.方法 探索硬组织切片的厚度、漂片温度、裱片方法、烤片温度和时间的最佳组合,针对阳离子防脱载玻片的使用条件进行反复比较,通过改进操作流程中的关键技术和需避免的问题,摸索出阳离子载玻片在硬组织切片裱片中的最佳应用条件,克服了硬组织切片制作技术中标本易破碎、切片易脱落及染色时染料容易吸附的缺点.结果 通过技术探索与改进,生物陶瓷支架材料体内植入后的类骨修复体标本的硬组织切片能保持其杂化后的组织结构与比较完整的材料结构,可进行Masson三色染色、苏木精-伊红(HE)及甲苯胺蓝染色.染色后镜下观察显示支架内杂化生长的组织结构完整、细胞形态清晰、切片质量好、生物陶瓷支架脱片少.荧光显微镜可观察到类骨修复体钙沉积现象完整.结论 改善了传统硬组织切片技术处理生物陶瓷材料时易于破坏组织-材料结构的缺点.改进的硬组织切片技术适应生物陶瓷材料在骨组织工程领域研究.     

Specific and artifactual labeling in the rat spinal cord and medulla after injection of monosynaptic retrograde tracers into the diaphragm

The use of fluorescent dyes has been a major improvement for paths tracing studies. However, these tracers present different properties and have to be chosen carefully. The present study compares the ability of different tracers to specifically label phrenic motoneurons (PMNs) innervating the rat diaphragm. The administration of fluorogold (FG) from the transected phrenic nerve specifically labeled PMNs in the ipsilateral spinal cord. However, when FG was injected into one hemidiaphragm, in addition with ipsilateral PMNs, a less intense artifactual labeling was observed in the spinal cord (mainly in contralateral PMNs) and in the medulla oblongata (mainly in the area postrema and cranial motor nuclei). Similar results were observed using horseradish peroxidase, while no labeling was observed after injection of nuclear yellow or diamidino yellow into the diaphragm. By contrast, the dextran amine fluororuby (FR) and the carbocyanine DiAsp selectively and exclusively labeled ipsilateral PMNs 2 or 3 weeks after injection into the diaphragm, respectively. The lipophilic properties of DiAsp and the high molecular weight of FR may prevent their diffusion to adjacent tissues and into the blood stream which seems to account for the artifactual labeling observed with the other tracers. The higher homogeneity and quality of the labeling observed with FR compared to DiAsp make it the most appropriate tracer for the specific monosynaptic fluorescent labeling of PMNs after injection into the diaphragm.     

阳离子脂质体-DNA复合物与脂质-鱼精蛋白-DNA复合物体外细胞转染率比较

采用薄膜-挤压法制备空白阳离子脂质体后,再分别制得阳离子脂质体-DNA复合物和脂质-聚阳离子-DNA复合物(Lipid-polycation-DNA lipopolyplexes,LPD);用凝胶阻滞实验,确定阳离子脂质体与质粒DNA的配比;用透射电镜观察阳离子脂质体-DNA复合物和LPD的形态,用激光粒度仪测定它们的粒径和zeta电位;用酶标仪测定它们对张氏(Chang)肝细胞、HepG2肝癌细胞的转染率。结果表明阳离子脂质体-DNA复合物和LPD的形态均近似于球体,但LPD的粒径明显较小;LPD对张氏(Chang)肝细胞和HepG2肝癌细胞的转染率均高于阳离子脂质体-DNA复合物。LPD是基因治疗的临床应用中一种更具前景的载体系统。     

脂质体介导RNAi的研究

本文选用阳离子脂质体Lipofectamine 2000为基因载体,使用沉默荧光素酶基因的小干扰RNA(siRNA)进行体外RNA干扰(RNAi),对阳离子脂质体转运siRNA的效率进行研究。首先以阳离子脂质体运载质粒DNA转染细胞,并以延滞实验对阳离子脂质体与siRNA的结合能力进行检测;然后通过基因载体将荧光素酶基因载入细胞,转运不同浓度的siRNA对其进行沉默,应用酶标仪对荧光素酶基因的表达进行分析,并用MTT法对转染后细胞存活率进行检测。结果表明:阳离子脂质体Lipofectamine 2000可以高效转运质粒DNA,并可与siRNA很好地结合。在较低的siRNA浓度下,对荧光素酶基因的沉默率达到较高的水平,转运siRNA转染细胞对细胞活性的影响很小,但细胞存活率随着siRNA浓度的增加而逐渐降低。通过优化实验条件,阳离子脂质体转运较低浓度的siRNA即可高效沉默目的基因。     

反义MCP-1转染兔平滑肌细胞及对其生长的影响

构建逆转录病毒载体反义单核细胞趋化蛋白1（LUCX-Anti-MCP－1）表达质粒,利用阳离子脂质体（Lipofectamine）将反义MCP－1导入体外培养的平滑肌细胞,通过PCR、Northern杂交检测外源基因的转染及其mRNA表达情况。应用3H胸腺嘧啶核苷（3H－TdR）掺入法了解反义MCP－1基因对细胞生长的影响．结果显示：Lipofectamine可以成功的将反义MCP－1基因导入体外培养的主动脉平滑肌细胞中,并实现外源基因的转录表达。且反义MCP－1基因对体外培养的平滑肌细胞生长没有影响。     

The Reduction of Azo Dyes by the Intestinal Microflora

Abstract

Azo dyes are widely used in the textile, printing, paper manufacturing, pharmaceutical, and food industries and also in research laboratories. When these compounds either inadvertently or by design enter the body through ingestion, they are metabolized to aromatic amines by intestinal microorganisms. Reductive enzymes in the liver can also catalyze the reductive cleavage of the azo linkage to produce aromatic amines. However, evidence indicates that the intestinal microbial azoreductase may be more important than the liver enzymes in azo reduction.

The azoreductase activity in a variety of intestinal preparations was affected by various dietary factors such as cellulose, proteins, fibers, antibiotics, or supplementation with live cultures of lactobacilli.

In this article, we examine the significance of the capacity of intestinal bacteria to reduce azo dyes and the conditions of azo reduction. Many azo dyes, such as Acid Yellow, Amaranth, Azodisalicylate, Chicago Sky Blue, Congo Red, Direct Black 38, Direct Blue 6, Direct Blue 15, Direct Brown 95, Fast Yellow, Lithol Red, Methyl Orange, Methyl Red, Methyl Yellow, Naphthalene Fast Orange 2G, Neoprontosil, New Coccine, Orange II, Phenylazo-2-naphthol, Ponceau 3R, Ponceau SX, Red 2G, Red 10B, Salicylazosulphapyridine, Sunset Yellow, Tartrazine, and Trypan Blue, are included in this article.

A wide variety of anaerobic bacteria isolated from caecal or fecal contents from experimental animals and humans have the ability to cleave the azo linkage(s) to produce aromatic amines. Azoreductase(s) catalyze these reactions and have been found to be oxygen sensitive and to require flavins for optimal activity.     

Supramolecular self-assembly forming a multifunctional synergistic system for targeted co-delivery of gene and drug

For developing a multifunctional bioreducible targeted and synergistic co-delivery system for anticancer drug paclitaxel (PTX) and p53 gene for potential cancer therapy, supramolecular self-assembled inclusion complex was prepared from PTX and star-shaped cationic polymer containing γ-cyclodextrin (γ-CD) and multiple oligoethylenimine (OEI) arms with folic acid (FA) conjugated via a disulfide linker. The inclusion complex, termed as γ-CD-OEI-SS-FA/PTX, was formed between PTX and the hydrophobic cavity of γ-CD core of the star polymer. The γ-CD-OEI-SS-FA/PTX complex further formed polyplexes with pDNA to give positively charged nanoparticles, becoming multifunctional supramolecular self-assembled co-delivery system for PTX and pDNA targeting to cancer cells that overexpress folate receptors (FRs). The results showed that the FA-targeted function induced higher gene transfection efficiency in the FR-positive KB cells. The redox-sensitive disulfide linker in the self-assembly system led to the detachment of the FA groups from the carrier after the FR-mediated endocytosis, which resulted in the release of the bound FRs followed by the recycling of the FRs from the cytosol onto the cell membrane surface, facilitating continuous FR-mediated endocytosis to achieve enhanced gene transfection. In addition, the complexed PTX was co-delivered to the cells with pDNA, which further enhanced the gene transfection even at low N/P ratios in the FR-positive KB cells. Further, the efficient delivery of wild-type p53 gene resulted in large cell population at sub G1 and G2/M phases, inducing significant cell apoptosis. Therefore, the multifunctional γ-CD-OEI-SS-FA/PTX self-assembly system with the synergistic effects of redox-sensitive FA-targeted and PTX-enhanced p53 gene delivery may be promising for cancer therapeutic application.     

A cationic cholesterol based nanocarrier for the delivery of p53-EGFP-C3 plasmid to cancer cells

The p53 protein mediated anti-tumor strategy is limited due to the lack of suitable delivery agent with insignificant immunogenic response, serum compatibility, and early and easy detection of the transfected cell population. To overcome these problems, we generated a p53-EGFP-C3 fusion construct which expressed easily detectable green fluorescence protein (GFP) and allowed an estimation of p53 mediated anti-tumor activity. A mixture of cationic cholesterol gemini (Chol-5L) with natural lipid, DOPE (molar ratio 1:4), acronymed as Chol-5LD, formed a nano-liposome as characterized by various physical methods. The prepared clone was evaluated for the expression of GFP and functional p53 in HeLa and two additional cell lines with varied p53 status namely, H1299 (p53^−/−) and HEK293T (p53^+/+). Transfected cells were screened using RT-PCR, Western blotting, FACS analysis, MTT, Trypan blue assay and visualized under a fluorescence microscope. The p53-EGFP-C3 fusion protein induced apoptosis in cancer cells as evident from DNA fragmentation, cell cycle analysis, Annexin-V staining and PARP cleavage assays. The transfection and apoptosis induction efficiency of Chol-5LD was significantly higher than commercial reagents Lipofectamine2000 and Effectene irrespective of the cell lines examined. Further it significantly decreases the xenograft tumor volume in nude mice tumors via apoptosis as observed in H&E staining.     

兰州牛肉面辣椒制品中苏丹红使用状况调查

目的:了解兰州市部分牛肉面辣椒制品中苏丹红一号的使用状况。方法:在兰州市所属8个区、县牛肉面馆随机抽取样品107份,以反相高效液相色谱进行测定。结果:15份辣椒粉中检出苏丹红Ⅰ、Ⅳ,其含量范围在2.18~110 mg/kg之间,辣椒制品中苏丹红的总检出率为14.0%,辣椒粉中苏丹红的总检出率为14.6%。结论:辣椒制品中违法添加苏丹红染料的现象依然存在,应引起有关部门的重视。