The effect of the histological properties of tumors on transfection efficiency of electrically assisted gene delivery to solid tumors in mice

Uniform DNA distribution in tumors is a prerequisite step for high transfection efficiency in solid tumors. To improve the transfection efficiency of electrically assisted gene delivery to solid tumors in vivo, we explored how tumor histological properties affected transfection efficiency. In four different tumor types (B16F1, EAT, SA-1 and LPB), proteoglycan and collagen content was morphometrically analyzed, and cell size and cell density were determined in paraffin-embedded tumor sections under a transmission microscope. To demonstrate the influence of the histological properties of solid tumors on electrically assisted gene delivery, the correlation between histological properties and transfection efficiency with regard to the time interval between DNA injection and electroporation was determined. Our data demonstrate that soft tumors with larger spherical cells, low proteoglycan and collagen content, and low cell density are more effectively transfected (B16F1 and EAT) than rigid tumors with high proteoglycan and collagen content, small spindle-shaped cells and high cell density (LPB and SA-1). Furthermore, an optimal time interval for increased transfection exists only in soft tumors, this being in the range of 5-15 min. Therefore, knowledge about the histology of tumors is important in planning electrogene therapy with respect to the time interval between DNA injection and electroporation.

Sustainability in infrastructure investment : building the business case

Many infrastructure agencies adopt sustainability objectives at a corporate level and incorporate sustainability targets and indicators as part of corporate reporting processes. These objectives are expected to translate to all stages of the project delivery process, including project selection. For infrastructure capital works projects and programs, a robust project management approach involves the development of a business case to guide investment decision making. A key tool in the assessment of project options and selection of a delivery strategy is Cost Benefit Analysis (CBA). Infrastructure providers are required to undertake cost benefit analysis to support project selection through regulatory approval and budgetary processes. This tool has emerged through the prism of economic analysis rather than sustainability. A literature review reveals the limitations of CBA alone to effectively evaluate economic, environmental and social externalities or impacts that apply over a long time frame, and that are ultimately irreversible. Multi-Criteria Analysis (MCA) has been introduced as a means to incorporate a wider array of factors into decision making such as sustainability. This, however, presents new challenges with issues around how to transparently represent wider community values in the selection of a preferred solution. Are these tools effective in assessing the wider sustainability costs and benefits taking into account that these are public works with long life spans and significant impacts across institutional boundaries? The research indicates a need to develop clear guidelines for investment decision making in order to better align with corporate sustainability objectives. Findings from the literature review indicate that a more sustainable approach to investment decision-making framework should include: the incorporation of sustainability goals from corporate planning documents; problem definition and option generation using best practice investment management guidelines; improved guidelines for Business Case development using a combination of both Cost Benefit Analysis and Multi-Criteria Analysis; and an integrated public participation process.

Public private partnership infrastructure delivery: Benefits and costs for society

This research provides additional knowledge on the benefits and costs to society, in particular of road transport procured through Public-Private Partnership (PPP) arrangements. Currently, the public sector comparator (PSC) and cost-benefit analysis (CBA) used to evaluate and measure the benefits and costs of PPP are limited in their capacity to predict and forecast long-term events. PPP is attractive to governments due to the non-upfront payment, perceived value for money, and risk allocation and transfer to the private investor. However, public sector remains the guarantor, and under-writer of the private investor's loan from financial institutions and other voluntary risks which are unlimited to future compensatory claims. The new knowledge from this research is the introduction of a framework capable of evaluating, and measuring the associated PPP benefits, as well as the costs, effects, and impacts to society which are protracted and sporadic by nature.

Effect of age, gender and mannose-binding lectin (MBL) status on the inflammatory profile in peripheral blood plasma of Australian blood donors

Transfusion of blood components has been associated with poor patient outcomes and, an overall increase in morbidity and mortality. Differences in the blood components arising from donor health, age and immune status may impact on outcomes of transfusion and transfusion-related immune modulation in recipients. The aim of this study was to investigate differences in inflammatory profile in donors and association with parameters including age, gender and deficiency status of pattern recognition molecule mannose-binding lectin (MBL). MBL level was determined by ELISA. Serum levels of interleukin (IL)-1α, IL-1β, IL-6, IL-8, IL-10, IL-12, tumour necrosis factor (TNF)-α, macrophage inflammatory protein (MIP)-1α, monocyte chemoattractant protein (MCP)-1, interferon (IFN)-α, and IFN-γ were examined by cytometric bead array (CBA). C-reactive protein (CRP) and rheumatoid factor (RF) were examined by immunoturbidimetry. This study demonstrated age was a parameter associated with the immune profile of blood donors, with significant increases in MCP-1 (p < 0.05) and RF (p < 0.05) and decreases in IL-1α evident in the older donors (61–76 years). Significant gender-associated differences in MCP-1, IL-12 and CRP plasma levels in the blood donor cohort were also reported. There was no significant difference in the level of any inflammatory markers studied according to MBL status. This study demonstrated that age and gender are associated with inflammatory profile in donors. These differences may be a factor impacting on outcomes of transfusion.

Zinc, cadmium and lead resistance mechanisms in bacteria and their contribution to biosensing

In bacteria resistance to heavy metals is mainly achieved through active efflux, but also sequestration with proteins or as insoluble compounds is used. Although numerous studies have dealt with zinc, cadmium and lead resistance mechanisms in bacteria, it has still remained unclear how different transporters are integrated into an effective homeostasis/resistance network and whether specific mechanisms for lead sequestration exist. Furthermore, since metals are toxic not only to bacteria but to higher organisms as well, it is important to be able to estimate possible biological effects of heavy metals in the environment. This could be done by determining the bioavailable amount of the metals in the environment with bacterial bioreporters. That is, one can employ bacteria that respond to metal contamination by a measurable signal to assess the property of metals to cross biological membranes and to cause harmful effects in a possibly polluted environment. In this thesis a new lead resistance mechanism is described, interplay between CBA transporters and P-type ATPases in zinc and cadmium resistance is presented and finally the acquired knowledge is used to construct bacterial bioreporters for heavy metals with increased sensitivity and specificity. The new lead resistance model employs a P-type ATPase that removes Pb2+ ions from the cytoplasm and a phosphatase that produces inorganic phosphate for lead sequestration in the periplasm. This was the first study where the molecular mechanism of lead sequestration has been described. Characterization of two P-type ATPases and two CBA transporters showed that resistance mechanisms for Zn2+ and Cd2+ are somewhat different than for Pb2+ as these metals cannot be sequestered as insoluble compounds as easily. Resistance to Zn2+ was conferred merely by the CBA transporter that could export both cytoplasmic and periplasmic ions; whereas, full resistance to Cd2+ required interplay of a P-type ATPase that exported cytoplasmic ions to periplasm and a CBA transporter that further exported periplasmic ions to the outside. The knowledge on functionality of the transporters and metal-inducible promoters was exploited in bioreporter technology. A transporter-deficient bioreporter strain that lacked exporters for Zn2+/Cd2+/Pb2+ could detect up to 45-fold lower metal concentrations than its wild type counterpart due to the accumulation of metals in the cell. The broad specificity issue of bioreporters was overcome by using Zn-specific promoter as a sensor element, thus achieving Zn-specific bioreporter.

Regional IAM: analysis of risk-adjusted costs and benefits of climate policies

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一种新的小鼠被毛突变基因定位

分别尝试用RAPD法和重组率测定法对所发现的被毛突变进行基因定位。结果为所选用的100个10bp RAPD引物中,87个获得了扩增产物,由于所获得的产物与小鼠表型间缺乏相关性,利用RAPD法未能将该基因定位到染色体上。以分布于小鼠11条染色体上的Idh1、Car2、Mup1、Pgm1、Hbb、Es10、Es1、Mod1、Gdc1、Ce2、Es3等生化基因位点为遗传标记,对分别与CBA/N和C57BL/6小鼠互交-回交所获得的F2代进行两点测试,结果表明该突变与Es3连锁,位于小鼠第11号染色体上。

Gene mapping of a new coat mutation in mouse

Gene mapping of a mouse coat mutation has been investigated. First, 100 10-bp random primers were used to amplify DNA, but the mutation could not be located by this method because there were no correlation between the amplified products and coat phenotypes. Second, by using Idh1, Car2, Mup1, Pgb1, Hbb, Es10, Es1, Mod1, Gdc1, Ce2, Es3 as genetic markers, linkage test crosses (two-point test) consisting of intercrossing uncovered BALB/c mice (homozygotes) to CBA/N and C57BL/6 mice with normal hair and backcrossing the heterozygotes of the F1 to the uncovered BALB/c mice were made. It was soon evident that the mutation was linked to Es3 on chromosome 11. Furthermore, three-point test was made by using Es3 and D11Mit8 (a microsatellite DNA) as genetic markers. The result showed that the mutation was linked to Es3 with the percentage recombination of (7.89 +/- 2.19)%, and linked to D11Mit8 with the percentage recombination of (26.38 +/- 3.57)%. The percentage recombination between Es3 and D11Mit8 was (32.90 +/- 3.81)%. The mutation was named Uncovered, with the symbol Uncv. According to the recombinations, the loci order was D11Mit8-26.30 +/- 3.57- Uncv-7.89 +/- 2.19-Es3. From the location on the chromosome, it was concluded that the mutation was a new mutation which affected the skin and hair structure of mouse. The Uncv has entered MGD (Mouse Genome Database).

多氯联苯污染土壤的生态修复研究

本研究针对我国土壤PCBs的污染特点，初步探讨了含有PCBs的变压器油分析与测定，两种典型的机合修复过程和PCBs代谢产物的植物毒理三个方面的问题，得出如下结论：1．采用一种经过检验的新前处理方法，分析变压器油样中含有2种二氯联苯，4种三氯联苯，4种4氯联苯，3种5氯联苯，1种六氯联苯，共13种PCBs同类物，各同类物在ΣPCB中占的百分含量在1.2％-13.4％之间。2．采用KMnO4和好氧降解菌系拙合时，祸合方式不同，藕合效果不同，土壤介质不同锅合的效果也存在差异。3．模拟缺氧条件下，不含脱氯微生物啤酒厂污泥，在经过一定迟滞期后（4星期），存在脱氯情况，添加按计卜油醇可减少迟滞期，有明显的诱导作用。单独投加零价金属的脱氯效果与其化学性质和投加量有关，Fe。和zno辛禺合厌氧微生物的脱氯效果要好于两者单独的脱氯效果，其中Zn0耦合厌氧微生物的脱氯效果最好。4，在实验区间内，两种白菜的POD可与根伸长、发芽率一起作为CBA的生态毒理指标，且比根伸长和发芽率敏感，SOD和CAT则不适合。

混合离子加速技术在单粒子效应试验中的应用

基于电子回旋共振(ECR)离子源的混合离子加速(CBA)技术,使回旋加速器可以快速地更换所加速离子的种类和能量,从而在单粒子效应敏感度评估以及探测器标定等方面发挥更大的作用。文章比较详细地阐述了混合离子加速技术原理及其在单粒子效应试验研究中的应用,并指出荷质比(q/A)的分辨率是精确引出所需离子的关键;增加引出圈数,可以提高不同离子间的相位差;改进ECR的注入措施,可以缩短更换离子种类的时间。

长白山阔叶红松林带内杨桦林动态模拟

利用改进的ZELIG .CBA模型模拟了长白山杨桦林的动态变化过程 .根据红松种源的存在与否 ,将模拟分为两种方案 ,结果表明 ,红松参加演替与否决定了山杨、白桦退出林分时间的早晚 ;红松种源存在时 ,演替的最终结果是阔叶红松林 ;无红松种源时 ,演替的最终结果是阔叶混交林 ,两种林分的生物量和蓄积量相差很大

氯苯甲酸植物毒性实验中抗氧化酶变化的量化研究

为研究氯苯甲酸(CBA)的植物毒性,评估生物化学参数能否作为CBA植物毒性的指示因子,采用对CBA敏感的小白菜种子和大白菜种子进行暴露实验,在根伸长抑制率为10%~50%的质量浓度范围内,研究了CBA剂量-抗氧化酶活性的关系。结果表明随着CBA质量浓度的升高,超氧化物歧化酶(SOD)活性总体上呈逐渐上升至峰值然后下降趋势,过氧化物酶(POD)活性逐渐降低,过氧化氢酶(CAT)活性与SOD活性近似,呈先升后降趋势,但幅度大于SOD活性。对CBA剂量-酶活性抑制率进行了回归分析,对拟合效果进行了显著性检验(P<0.05),并求出相应的半效应浓度(EC50),实验材料的SOD和CAT活性的EC50均在实验区间之外,POD活性的EC50则在实验区间之内,表明在实验区间内,SOD和CAT活性不敏感,POD活性为有效指标。

交联型聚乙烯亚胺智能基因载体的制备及PEG化影响

使用胱胺双丙烯酰胺(CBA)对低分子量聚乙烯亚胺(PEI)进行交联反应制备智能降解型聚阳离子基因载体.通过与聚乙二醇(PEG)反应得到不同程度PEG化的聚阳离子载体.利用核磁、黏度测试、粒度仪、zeta电位仪和凝胶电泳对聚阳离子载体及其与DNA的复合物进行了表征.研究表明随着PEG含量的增加,聚阳离子载体/DNA复合物颗粒粒径变小、表面正电荷降低,PEG具有明显的屏蔽作用,但过多的PEG也使载体与DNA复合能力下降.通过MTT细胞毒性测试和荧光素酶质粒转染实验得出,含二硫键的交联型阳离子聚合物在测试范围内显示了非常低的细胞毒性,最佳转染效率是PEI25k的4倍,PEG化后其细胞毒性得到进一步改善,转染效率却明显降低.

SYNTHESIS AND CHARACTERIZATION OF A CROSSLINKING POLYETHYLENIMINE AS SMART GENE CARRIER AND EFFECTS OF PEGYLATION DEGREE

A smart biodegradable cationic polymer (CBA-PEI) based on the disulfide bond-containing cross-linker cystamine bisacrylamide (CBA) and low molecular weight branched polyethylenimine (1800-Da, PEI1800) was successfully synthesized by Michael addition reaction in our recent study. Furthermore, a series of copolymers (CBA-PEI-PEG) with different PEGylation degree were obtained by the mPEG-SPA (5000-Da) reacting with CBA-PEI at various weight ratios directly. The molecular structures of the resulting polymers CBA-PEI and CBA-PEI-PEG were evaluated by nuclear magnetic resonance spectroscopy (H-1-NMR) and capillary viscosity measurements, all of which had successfully verified formation of the copolymers. The polymer/DNA complexes based on CBA-PEI and CBA-PEI-PEG were measured by dynamic light scattering and gel retardation assay. The results showed that the particle size and zeta potential of complexes were reduced with increasing amount of PEG grafting, even no particle formation. The particle size of CBA-PEI/DNA complexes was in range of 103.1 to 129.1 nm, and the zeta potential was in range of 14.2 to 24.3 mV above the 2:1 weight ratio. In the same measure condition, the particle size of CBA-PEI-PEG complexes was reduced to a range of 32.2 to 55 nm, and the zeta potential was in range of 9.3 to 13.8 mV at the 2:1 weight ratio.

Luminescence properties of sol-gel derived silica gels doped and undoped with RE-complexes (RE=Eu, Tb)

The luminescence properties of silica gels and silica gels doped with two rare earth complexes, Eu(TTA)(3) and Tb(o-CBA)(3) (TTA=thenoyltriffuocetate, o-CBA=o-chlorobenzoic acid) are reported and discussed. Pure silica gels show a blue luminescence, and the maximum excitation and emission wavelengths depend strongly on the solvents used. Both of the studied rare earth complexes exhibit the characteristic emissions of the rare earth ions in silica gels, i.e., Eu3+5D0-->F-7(J)(J=0,1,2,3,4), Tb3+5D4-->F-7(J)(J=3,4,5,6) transitions. Compared with the pure RE-complexes powder, the silica gels doped with RE-complexes show fewer emission lines of the rare earth ions. Furthermore the rare earth ion (Tb3+) presents a longer lifetime (1346 mu s) in silica gel doped with Tb(o-CBA)3 than in pure Tb((o-CBA)(3) powder (744 mu s). The reasons responsible for these results are discussed in the context.