Predictors of Occlusion of Hepatic Blood Vessels after Irreversible Electroporation of Liver Tumors

PurposeTo examine predictors of midterm occlusion in portal and hepatic veins within or adjacent to the ablation zone after irreversible electroporation (IRE) of liver tumors.Materials and MethodsThis retrospective cohort analysis included 39 patients who underwent CT-guided IRE of liver tumors. Vessels within or adjacent to the ablation zone were identified on CT images acquired immediately after the procedure, and the positional relationships with the ablation zone (within/adjacent), locations (proximal/distal), and diameters (< 4 mm or ≥ 4 mm) were evaluated. Using contrast-enhanced follow-up scans, each vessel was classified as patent, stenosed, or occluded. Associations between vessel occlusion and each variable were investigated.ResultsOverall, 33 portal veins and 64 hepatic veins were analyzed. Follow-up scans showed occlusion in 12/33 (36.7%) portal veins and 17/64 (26.6%) hepatic veins. Vessels within the ablation zone were occluded significantly more frequently than vessels adjacent to the ablation zone (portal: 55.6% [10/18] vs 13.3% [2/15], P = .04; hepatic: 45.4% [15/33] vs 6.4% [2/31], P = .011). Vessels with a diameter < 4 mm were also occluded significantly more frequently than vessels with a diameter ≥ 4 mm (portal: 72.7% [8/11] vs 18.1% [4/22], P = .011; hepatic: 54.8% [17/31] vs 0% [0/33], P < .001). The respective positive and negative predictive values for occlusion of vessels categorized as both within and < 4 mm were 88% (7/8) and 82% (20/25) for portal veins and 79% (15/19) and 96% (43/45) for hepatic veins.ConclusionsMidterm vessel occlusion after liver IRE could be predicted with relatively high accuracy by assessing ablation location and vessel diameter.     

Synergistic effect of low dose Cyclosporine A and human interleukin 10 overexpression on acute rejection in rat lung allotransplantation

Objective: Electroporation mediated transfer of plasmid DNA into peripheral muscle results in high transfection efficiency. The aim of this study was to investigate the effect of gene transfer of human IL-10 (hIL-10) into the tibialis anterior muscle (MTA) in combination with low dose Cyclosporine A (CsA) on acute rejection of lung allografts in the rat. Methods: Lung allotransplantation was performed from male BN donor to male Fisher F344 rats. Gene transfer was achieved by intramuscular injection into the MTA of the recipient followed by electroporation (4×20 ms impulses at 200 V/cm) 24 h prior to the transplantation. Group A (n=5) received CsA (2.5 mg/kg bw ip) for 5 days post-transplant and group B (n=5) 2.5 μg of PCIK hIL-10 (plasmid expression vector containing human CMV immediate early gene promoter and enhancer) and a low dose CsA (2.5 mg/kg bw i.p.). Graft function was assessed by blood gas at day 5 after exclusion of the native lung. Animals were sacrificed and blood was drawn to measure serum hIL-10 levels (ELISA) and tissue was sampled for histological grading of rejection. Results: Local expression of hIL-10 was confirmed at the mRNA level by in situ hybridization. All group A control animals showed severe signs of rejection. At day 5 all grafts in group B showed good gas exchange mean PaO2 233±123 mmHg, vs 44±8 mmHg in group A. Histological examination revealed moderate to severe rejection in all animals in group A (IIIB, ISHLT) in contrast to low moderate rejection in group B (II–IIIA). hIL-10 serum levels on day 5 were 14±7 pg/ml in group B vs. 0 in group A. Conclusions: Electroporation mediated hIL-10 overexpression in a peripheral muscle of the recipient in combination with low dose CsA reduces acute rejection in this model of rat lung allotransplantation.     

电穿孔增强核酸疫苗免疫反应的研究进展

核酸疫苗自诞生以来在肿瘤、感染性疾病和自身免疫性疾病等方面显示出其独特的优越性。目前,研究如何增强核酸疫苗的免疫原性是一大热点,在众多方法中,电穿孔通过增加细胞对DNA的摄取,使表达的目的抗原增多,从而明显地增强了核酸疫苗诱导的免疫反应。就电穿孔技术在核酸疫苗研究领域的应用作一综述。     

Transdermal Delivery of Metoprolol by Electroporation

Electroporation, i.e., the creation of transient pores in lipid membranes leading to increased permeability, could be used to promote transdermal drug delivery. We have evaluated metoprolol permeation through full thickness hairless rat skin in vitro following electroporation with an exponentially decaying pulse. Application of electric pulses increased metoprolol permeation as compared to diffusion through untreated skin. Raising the number of twin pulses (300 V, 3 ms; followed after 1 s by 100 V, 620 ms) from 1 to 20 increased drug transport. Single pulse (100 V, 620 ms) was as effective as twin pulse application (2200 V, 1100 V or 300 V, 3 ms; followed after 1 s by 100 V, 620 ms). In order to investigate the effect of pulse voltage on metoprolol permeation, 5 single pulses (each separated by 1 min) were applied at varying voltages from 24 to 450 V (pulse time 620 ms). A linear correlation between pulse voltage and cumulative metoprolol transported after 4 h suggested that voltage controls the quantity of drug delivered. Then, the effect of pulse time on metoprolol permeation was studied by varying pulse duration of 5 single 100 V pulses from 80 to 710 ms (each pulse also separated by 1 min). Cumulative metoprolol transported after 4 h increased linearly with the pulse time. Therefore, pulse time was also a control factor of the quantity of drug delivered but to a lesser extent than the voltage at least at 100 V. The mechanisms behind improved transdermal drug delivery by electroporation involved reversible increased skin permeability, electrophoretic movement of drug into the skin during pulse application, and drug release from the skin reservoir formed by electroporation. Thus, electroporation did occur as shown by the increased transdermal permeation, on indicator of structural skin changes and their reversibility. Electroporation has potential for enhancing transdermal drug delivery.     

Current Status and Future Prospects of Transdermal Drug Delivery

Pharmaceutical Research -     

胰岛素脂质体的制备及在电致孔下的经皮渗透

采用反相蒸发法制备了平均粒径122.7nm的胰岛素脂质体,并考察了电致孔经皮转运情况.结果表明,在电致孔条件下,胰岛素脂质体2h累积渗透量是载药脂质体被动扩散的1倍;是原药及其与空白脂质体混合物的2～3倍.     

电致孔对睾酮透皮转运的影响

研究了电致孔技术对睾酮透皮转运的影响,对电压、脉冲持续时间和电极的影响进行了初步探讨.结果表明,电致孔可增大药物的透皮转运速率及其累积透过量,且电力学参数与透皮吸收增量呈正相关,电极也明显影响电致孔透皮速率.     

电穿孔法基因转染K562细胞条件的优化

目的以绿色荧光蛋白(GFP)为观察指标优化K562细胞的电穿孔基因转染条件。方法通过改变悬液体积、温度及缓冲液、质粒浓度等转染条件,采用不同条件组合后用电穿孔法将质粒DNA转入K562细胞,通过流式细胞仪和荧光显微镜观察转染效率。结果①在电压250V、电容950μF的条件下.K562细胞得到58.6%的最大转染率。②应用0.4mL细胞悬液体积,当质粒浓度≥20μg/mL时可得到较高的转染效率。③温度和缓冲液中的血清成分对电穿孔效率影响不大。结论电穿孔是一种高效的基因转染法,通过优化条件,可提高转染率。     

电致孔条件下巴布剂中青藤碱透皮吸收的药动学研究

目的:将巴布剂结合电致孔透皮给药,与被动扩散透皮给药进行比较,初步考察在电致孔条件下巴布剂中青藤碱透皮吸收的药动学特点.方法:以青风藤为模型药物,以活体兔分别进行被动扩散给药(PD)和电致孔透皮给药(EP),高效液相色谱仪测定不同时间的血药浓度,采用统计矩分析法处理分析血药浓度数据.结果:电致孔技术透皮给药的AUC0→∞为43.396,是被动扩散的1.32倍,体内平均滞留时间为20.025,是被动扩散的86%,cmax为1.825,是被动扩散的1.31倍, tmax减小,比被动扩散提前4 h;消除速率常数λ二者一致;电致孔技术透皮给药的药-时曲线比被动扩散的药-时曲线平滑且下降较慢.结论: 将电致孔技术与巴布剂结合能够提高药物透皮吸收的速度和程度,从而提高生物利用度.