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排序方式: 共有289条查询结果,搜索用时 250 毫秒
61.
Aihua Zhou Man Liu Cristina Baciu Brigitte Glück Hermann Berg 《Journal of electroanalytical chemistry (Lausanne, Switzerland)》2000,486(2):220-224
Electroporation of membranes is used widely for drug delivery. Photodynamic action consists of three main steps: (A) incorporation of the sensitizer through a membrane into cells; (B) photoxidation of cell constituents and (C) reoxidation of the reduced sensitizer by oxygen etc. The mechanisms of (B) and (C) have been studied widely in past decades. However, the mechanism of transport (A) of sensitizers to targets as the rate limiting step has not been studied to the same extent. Therefore we applied membrane and cell wall electroporation of human histiocytic lymphoma U937 and Saccharomyces cerevisiae cells in order to incorporate rapidly the reliable photodynamic agents thiopyronine, protoporphyrin, zinc phthalocyanine, copper phthalocyanine sulfonate, adriamycin and daunomysin, well-tried cytostatic agents. Depending on field strength and pulse width, 50–90% of cells become electroporated, then the dye diffuses rapidly into the cells, which reseal their membranes over a period of 6–10 min. Illumination for 10–15 min destroys all resealed cells faster than the same amount of unporated cells as in the case of the control (without pulse treatment) either by oxidation of cell components caused by excited dyes or singlet oxygen treatment. By this synergism of electroporation and photodynamic action at the same time, it is possible to kill all cells in a much shorter time than under usual conditions, e.g. in the control suspension. A combination of electrochemotherapeutic needle electrodes with a light conductor for a LASER connection will be effective for therapy. 相似文献
62.
Transdermal iontophoresis of 5-fluorouracil combined with electroporation and laser treatment 总被引:5,自引:0,他引:5
The influence of iontophoresis and other physical enhancement methods such as electroporation and erbium:yttrium-aluminum-garnet (YAG) laser on the skin permeation of 5-fluorouracil (5-FU) was examined. Iontophoresis increased the in vitro transdermal transport of both the anionic and non-ionic forms of 5-FU. A combination of electroporation pretreatment and subsequent iontophoresis resulted in a higher permeation of 5-FU than either technique alone. It appeared that electroporation treatment exerted a disruptive influence on the stratum corneum (SC). The SC layers in the skin were partly ablated by the laser, resulting in a great enhancement effect on the skin permeation of 5-FU. Application of iontophoresis further increased the drug permeation across laser-pretreated skin. The laser was consistently the most potent technique to enhance 5-FU delivery among the physical enhancement methods examined in this study. 相似文献
63.
Ghartey-Tagoe EB Morgan JS Ahmed K Neish AS Prausnitz MR 《International journal of pharmaceutics》2004,270(1-2):127-138
This study was conducted to determine if electroporation can deliver membrane-impermeant molecules intracellularly to intact, physiologically competent monolayers that mimic the intestinal epithelium. In addition, the long-term effects of electroporation on these monolayers were studied to determine the kinetics with which monolayers recover barrier function. Caco-2 and T84 cells were electroporated as monolayers using calcein and fluorescein-labeled bovine serum albumin as marker molecules for measuring delivery into cells. Confocal microscopy and flow cytometry were used, respectively, to visualize and quantify uptake of these molecules. Transepithelial resistance was used as a measure of physiologic barrier function. We found that intracellular uptake of calcein and bovine serum albumin occurred uniformly throughout both types of model epithelia and increased as a function of voltage, pulse length, and pulse number. There was no significant difference in uptake resulting from single and multiple pulses of the same total exposure time. We also observed that monolayers exposed to electroporation that induced uptake of up to 106 molecules/cell were able to recover normal barrier function within one day. These findings suggest that electroporation may be useful for intracellular delivery into monolayers to study epithelial biology and, possibly, for drug delivery to intestinal epithelium. 相似文献
64.
Schmotzer CA Dunlap-Brown ME Butler SP Velander WH Gwazdauskas FC 《Journal of assisted reproduction and genetics》2003,20(4):148-152
Purpose: The objective was to establish the parameters for reversible electroporation of murine embryos.
Methods: In Trial 1, murine presumptive zygotes received an electrical pulse of 5, 10, or 20-s duration, and one of five voltages (100, 200, 250, 300, or 400 V). In Trial 2, embryo orientation within the electroporation chamber was evaluated with 250 or 400 V at a pulse period of 10 s.
Results: Presumptive zygotes that received 400 V at each pulse length and zygotes exposed to 20 s at each voltage had the lowest embryonic development (P < 0.05). Presumptive zygotes that received 250 V had higher development compared to 400 V, irrespective of orientation (P < 0.01), but development was lower than the controls (P < 0.01).
Conclusions: Electrical stimulation of presumptive zygotes can have a detrimental impact on early embryo development, but low amounts of stimulation may allow for potential gene transfer in transgenic experimentation. 相似文献
65.
Iontophoresis of colchicine solution through electroporated skin showed maximum enhancement as compared to iontophoresis and electroporation alone. Encapsulation of colchicine in positively charged liposomes further augmented the delivery,with the amount of drug in the receptor after 24 h being 1348 342 mug/cm2 when iontophoresis was performed through electroporated skin as compared to 666 38mug/cm2 when it was performed through nonelectroporated skin and 41 18mug/cm2 when only electroporation was performed. The impedance of the skin was observed to drop sharply due to electroporation, with a postpulse recovery of about 30% over 24h. Also the total amount transported was compared to the total charge delivered in the case of each of the protocols. Hence this serves as initial evidence for potential of charged liposomes for the enhanced transdermal delivery of nonionized or neutral drugs using a combination of electroporation and iontophoresis. 相似文献
66.
Summary An improved method for PEG-mediated transformation of the fungal pathogen Fusarium oxysporum was developed which led to at least a 10-fold increase in transformation frequency. This improvement was gained through the analysis of biological factors, viz., protoplast origin, plasmid modifications and protoplast/plasmid ratio. Elecroporation, a recently developed method for introducing DNA into many cell types, was successfully applied. It gave similar transformation efficiencies to those obtained with the chemical method, and thus appeared a valuable alternative. Qualitative features such as integration events were also analysed. Molecular analysis of transformants revealed that a single copy of plasmid DNA was preferentially integrated by electroporation. The respective advantages of the two DNA transfer methods are discussed.Abbreviations (CM)
complete medium (Daboussi 1980)
- (MM)
minimal medium (Daboussi 1980)
- (MS)
10 mM MOPS, pH 6.3, 1 M sorbitol
- (MSC)
MS with 10 mM CaCl2
- (HS)
5 mM HEPES, pH 6.3, 20% sucrose
- (PEG)
polyethylene glycol
- (FD)
microfarad 相似文献
67.
Genetics of rickettsiae 总被引:5,自引:0,他引:5
L. P. Mallavia 《European journal of epidemiology》1991,7(3):213-221
68.
肿瘤治疗方法主要有外科、化疗、放疗、免疫治疗及它们的联合使用。近20年来,电脉冲疗法因其抑瘤效率高、参数容易控制、无残余毒性等特点,受到国内外专家学者的广泛关注。 相似文献
69.
铜绿假单胞菌噬菌体PaP3基因组电转化宿主菌的条件初探 总被引:1,自引:0,他引:1
目的:研究将铜绿假单胞菌噬菌体PaP3基因组DNA电转入其宿主菌并获得噬斑的基本条件。方法:以铜绿假单胞菌PA3作受体菌,将噬菌体PaP3基因组DNA通过电转化导入受体菌中,研究细胞生长状态、感受态细胞的制备方式、电场强度、DNA浓度和细胞密度等条件对转化效率的影响。结果:在含50μg/ml红霉素的LB培养液中培养宿主菌14~16 h,以100 mmol/L蔗糖溶液为介质,在25℃条件下制备感受态并使其浓度达到1011/ml,电转参数为12 kV/cm,300Ω,25μF,在此组条件下能获得较高的转化效率,最高可达2.1×103pfu/μg的DNA。结论:确定了一组电转条件,成功地将铜绿假单胞菌噬菌体完整基因组导入PA3中,并形成噬斑,为铜绿假单胞菌噬菌体的深入研究奠定了基础。 相似文献
70.