胞嘧啶脱氨酶/5-氟胞嘧啶系统治疗胰腺癌体内实验研究

目的探讨胞嘧啶脱氨酶(CD)基因对胰腺癌的杀伤作用机制。方法 应用细菌内同源重组法构建含CD基因的腺病毒载体,将Patu8988、SW1990胰腺癌细胞皮下接种BALB/C裸鼠建立胰腺癌的移植瘤模型,重组CD腺病毒液以1010 pfu/ml原位注射入肿瘤,每周2次,24 h后腹腔给予前药5-氟胞嘧啶(5-FC),连续4周。结果 CD基因原位转导的裸鼠移植瘤生长明显受抑。Patu8988移植瘤治疗组肿瘤重量为(587.7±107.8)mg,SW1990移植瘤组治疗组肿瘤重量为(597.6±159.4)mg,对照组重量为(2 042.4±608.0)mg(P<0.01)。结论重组CD基因的腺病毒载体对胰腺癌不仅转染效果强,加用前药5-FC后,可直接或通过旁观者效应抑制移植瘤的生长。     

5-氟胞嘧啶对CD基因修饰的胰腺癌细胞作用的电镜观察

目的　应用微观检查方法探讨 5 氟胞嘧啶 (5 flurocytosine,5 FC)对胞嘧啶脱氨酶 (cyto sinedeaminase ,CD)基因修饰的胰腺癌细胞体外、体内杀伤的作用机制。方法　构建含大肠杆菌胞嘧啶脱氨酶基因的腺病毒载体 ,经包装、扩增后制备纯化高效的CD腺病毒液 ,体外培养胰腺癌细胞并建立胰腺癌裸鼠皮下移植瘤模型 ,电镜下观察转染CD基因及加入前药 5 FC后胰腺癌细胞的微观变化情况。结果　含CD基因腺病毒载体经酶切鉴定正确 ,病毒滴度为 2× 10 11pfu/ml,电镜观察到CD/5 FC系统对胰腺癌的体外杀伤是一种凋亡现象而非坏死 ,而体内实验观察到坏死与凋亡并存 ,同时亦观察到淋巴细胞浸润。结论　CD/5 FC系统对胰腺癌的作用 ,有多种因素及旁观者效应参与其内。体外结果显示 ,凋亡小体的摄入和毒性代谢产物的直接作用可能起主要作用。体内实验结果显示细胞坏死与凋亡并存 ,免疫反应在抑制肿瘤生长中也起着重要作用。     

腺病毒载体介导的自杀基因对MFC小鼠前胃癌细胞的体外杀伤作用

提高转基因效率,建立高效自杀基因杀伤胃癌肿瘤细胞的方法。方法：首先构建含CD基因的重组腺病毒载体并对载体进行包装、收获病毒上清并纯化。将重组病毒液转染MFC胃癌细胞进行体外抑瘤实验。结果：含CD基因的重组腺病毒载体经酶切鉴定选出：包装纯化后,检测病毒浓度为1.2×1012颗粒/ml。体外实验中,转CD基因的MFC细胞在5-FC作用下生长明显受抑(P<0.01,n＝9)。结论：腺病毒载体转导的CD基因提高了转染效率,为大量杀伤胃癌细胞奠定了基础。     

AdKDR-CDglyTK融合基因系统治疗胰腺癌的实验研究

目的 观察腺病毒介导的KDR启动子驱动的CD/TK融合双自杀基因系统(以下简称为AdKDR-CDglyTK)对胰腺癌的治疗作用.方法 采用培养细胞移植法,将人胰腺癌细胞系Capan-2接种于裸鼠背部皮下,建立裸鼠人胰腺癌移植瘤模型.将20只裸鼠随机分为4组,每组5只.分组方法:Ⅰ组:注射重组腺病毒AdKDR-CDglyTK与前药5-FC与GCV;Ⅱ组:仅注射前药5-FC与GCV;Ⅲ组:仅注射重组腺病毒AdKDR-CDglyTKⅣ组:空白对照,不施加任何处理.重组腺病毒AdKDR-CDglyTK采用瘤体内多点注射,5-FC与GCV给药方法采用腹腔内注射的方法,观察各组小鼠的生存状况及肿瘤体积、瘤重、肿瘤生长抑制率、常规病理等指标;应用透射电镜观察细胞超微结构,用TUNEL法检测细胞凋亡率,比较观察各治疗组的治疗效果;并对各组的肿瘤组织行RTPCR的检测,以了解有无双自杀基因CDglyTK的表达.结果 第Ⅰ组裸鼠移植瘤的生长显著受到抑制,第Ⅱ、Ⅲ、Ⅳ组肿瘤生长情况无明显差别.第Ⅰ组肿瘤细胞凋亡指数为(34.20±4.60)%,较对照组显著增加(P=0.00).结论 AdKDR-CDglyTK联合前药5-FC及GCV对人胰腺癌Capan-2细胞具明显的抑制作用,并且诱导裸鼠体内人胰腺癌Capan-2细胞的凋亡.其可能的机制是通过下调凋亡抑制基因Bcl-2的表达.     

胞嘧啶脱氨酶基因、单纯疱疹病毒胸苷激酶基因治疗裸鼠肝门部胆管癌皮下移植瘤的研究

目的　观察胞嘧啶脱氨酶基因 (CD)、单纯疱疹病毒胸苷激酶基因 (HSV tk)共表达对裸鼠人肝门部胆管癌皮下移植瘤的治疗作用。方法　用转染有双自杀基因的包装细胞PA3 17产生的病毒上清 ,感染裸鼠肝门部胆管癌皮下移植瘤 ,给予前体药物 5 氟胞嘧啶 (5 FC) 5 0 0mg/kg体重和 /或无环鸟苷 (GCV ) 10 0mg/kg体重后 ,1次 /d ,共 10d ,观察肿瘤的生长情况。 结果　双自杀基因在裸鼠肝门部胆管癌皮下移植瘤中稳定表达 ,转基因组肿瘤的生长明显受到抑制 (P <0 .0 1) ;CD tK / 5 FC GCV组、CD/ 5 FC组、tK/GCV组抑瘤率分别为 88.3 1%、63 .5 2 %、65 .0 5 %。双自杀基因组与单自杀基因比较差异有显著性 (P <0 .0 5 )。结论　双自杀基因可明显抑制裸鼠肝门部胆管癌皮下移植瘤生长 ,较单一自杀基因有更强的抗肿瘤作用     

双自杀基因重组腺病毒对胰腺癌细胞特异性杀伤作用

目的 研究腺病毒介导的KDR启动子驱动CD/TK融合基因系统(Ad-KDR-CDTK)对胰腺癌细胞Capan-2特异性的杀伤作用.方法 重组腺病毒体外感染表达KDR的Capaw2细胞株,用不表达KDR的肝癌细胞HepG2做对照.观察其感染效率并以RT-PCR方法 检测转基因细胞CDTK的表达,然后给予不同浓度的前药更昔洛韦(ganciclovir,GCV)和5-氟胞嘧啶(5-fluorocy-tosine,5-FC),MTT法观察该体系对Capan-2和HepG2细胞生长增殖的影响及其旁观者效应;电镜观察细胞的病变;流式细胞仪检测细胞周期的变化和DNA含量的变化.建立Capan-2裸鼠皮下移植瘤模型,瘤内注射Ad-KDR-CD/TK,腹腔注射前药GCV(50 mg·kg-1·d-1)和5-FC(500 mg·kg-1·d-1)14 d,观察肿瘤生长抑制效应.结果 腺病毒对两种细胞株的感染率相似,其感染率随腺病毒滴度的增高而递增.RT-PCR方法 检测发现转染Ad-KDR-CDTK的Capan-2细胞有目的 基因表达.MTT法检测显示前药呈剂量依赖性抑制Capan-2生长,而不表达KDR的肝癌细胞HepG2对前药不敏感,且观察到该体系对Capan-2明显的旁观者效应.电镜下可见Capan-2有凋亡改变.用流式细胞仪测定用药组出现典型的凋亡峰;细胞周期分析显示治疗后细胞G0-G1期比率增多,G2-M及S期细胞减少.在Capan-2裸鼠移植瘤模型中,该双自杀基因系统能够显著抑制肿瘤的生长.结论 KDR启动子可调控双自杀基因体系选择性杀伤胰腺癌细胞Capan-2,诱导胰腺癌细胞凋亡,并可显著抑制人胰腺癌裸鼠移植瘤的生长.     

重组腺病毒载体介导人OSM 基因对胰腺癌细胞增殖的抑制作用及对裸鼠致瘤性的影响

目的　构建了含人抑瘤素M (humanoncostatinM ,hosm)基因的复制缺陷型重组腺病毒载体 ,观察其对胰腺癌细胞株BxPC3 在体外生长抑制情况及在裸鼠致瘤性改变的作用 ,为胰腺癌的基因治疗提供参考。方法　用含hosm基因的缺陷型腺病毒载体转染人胰腺癌细胞株 ,用RT PCR法检测外源hosm基因在其中的表达 ;苔盘蓝染色、细胞计数法检测ad hosm对BxPC3 的体外增殖抑制情况 ;裸鼠皮下接种转染ad hosm的BxPC3 ,观察其对肿瘤形成率的影响。结果　hosm基因在转染细胞能有效的表达。体外试验示ad hosm能明显抑制BxPC3 的生长 ,ad hosm能抑制BxPC3 在裸鼠中的成瘤作用。结论　重组腺病毒介导hosm基因表达能有效抑制BxPC3 在体外、体内的增殖 ,提示重组腺病毒介导的hosm基因治疗可能成为胰腺癌治疗的侯选方案。     

腺病毒介导双自杀基因CD/TK对人肝癌细胞株Bel7402的抑制作用

目的探讨含胞嘧啶脱氨酶(CD)／5-氟胞嘧啶(5-Fc)单纯疱疹病毒1型胸腺嘧啶激酶基因融合自杀基因(CD／TK)的重组腺病毒治疗肝癌的疗效。方法重组腺病毒Ad．CD／TK感染人肝癌细胞Bel7402,用噻唑蓝(MTT)方法观察不同浓度5-Fc和无环鸟苷(GCV)对其杀伤效应; 建立Bel7402裸鼠皮下移植瘤模型,瘤内注射Ad．CD／TK,腹腔注射GCV(50 mg／kg体重)和／或5- Fc(500 mg／kg体重)10 d,观察肿瘤生长抑制效应。结果在对感染Ad．CD／TK的Bel7402细胞的体外杀伤实验中,GCV的IC50为(12．1±2．3)μmol／L,5-Fc的IC50为(223±15)μmol／L,并且两者有协同效应。在Bel7402裸鼠移植瘤模型中,联合Ad．CD／TK和GCV、5-Fc能够显著抑制肿瘤的生长。结论腺病毒为载体的双自杀基因转染和前药的应用对人肝癌细胞的体内、体外治疗疗效明显。     

VEGF_(121)反义核酸抑制裸鼠胰腺癌移植瘤的增殖及血管生成

目的:探讨VEGF121反义核酸对裸鼠胰腺癌移植瘤的增殖及血管生成的影响,探索通过VEGF反义核酸抑制肿瘤生长.方法:将稳定转染有VEGF反义核酸pcDNA3-ASVEGF121的胰腺癌细胞系Bx-PC-3接种于裸鼠背部皮下.将实验鼠分为实验组、对照组和空白组.定期测定裸鼠移植瘤体积,免疫组织化学法检测裸鼠移植瘤VEGF、Flk-1表达水平.测定裸鼠移植瘤微血管密度.结果:VEGF反义核酸转染BxPC-3细胞后,裸鼠胰腺癌移植瘤生长明显减缓.移植瘤VEGF表达明显受到抑制,Flk-1表达水平上调.裸鼠胰腺癌移植瘤微血管密度明显降低.结论:人反义核酸VEGF121能显著抑制裸鼠胰腺癌移植瘤的增殖,并能抑制裸鼠胰腺癌移植瘤的血管生成.     

腺病毒载体介导的双自杀基因对人胆管癌细胞QBC939的体外杀伤实验

目的观察腺病毒介导的胞嘧啶脱氨酶/单纯疱疹病毒-1-胸苷激酶(CD/TK)双自杀基因对人胆管癌细胞 QBC939的体外杀伤作用。方法 CD/TK 克隆入穿梭载体成为 pAdtrack-CMV-CD/TK,与骨架载体 pAdeasy-1在细菌内同源重组为 pAd-CD/TK,经 PacⅠ酶切,293细胞包装、扩增、纯化后,体外转染人胆管癌细胞 QBC939,并给予前药5-FC 或 GCV,观察其体外杀伤效果。结果含 CD/TK 基因的重组腺病毒鉴定正确,扩增纯化后,病毒滴度为1×10~(11)颗粒/ml。重组腺病毒对 QBC939细胞在感染倍数(m.o.i)为100时的转染效率为90%,在 m.o.i50感染时,0.1mmool/L的5-FC 及10 μmol/L 的 GCV 对 QBC939细胞的杀伤率为80%,明显高于单用5-FC 与 GCV 的效应。结论双自杀基因以腺病毒为载体对人胆管癌细胞转染效率高,体外杀伤效应明显。腺病毒介导的双自杀基因治疗有望成为治疗胆管癌的有效方法。     

Reduction of Plasma Fibrinogen, Immunoglobulin G, and Immunoglobulin M Concentrations by Immunoadsorption Therapy with Tryptophan and Phenylalanine Adsorbents

Abstract Immunoadsorption (1A) therapy with tryptophan (TR-350) or phenylalanine (PH-350) adsorbents has been used to reduce the concentration of serum antibodies in human lymphocyte antigen (HLA)-immunized patients. Other forms of plasma purification have been reported to reduce the level of fibrinogen, which affects the blood properties. In this study we investigated the effects of IA therapy using both adsorbents on plasma fibrinogen and immunoglobulins G and M in 13 patients (8 patients were treated with TR-350, and 5 patients were treated with PH-350). During each session 1 plasma volume (2.8 ± 0.4 L of plasma) was processed through the immunocolumn and then returned to the patient together with the blood cells. Compared with the pretreatment values, the plasma fibrinogen, IgG, and IgM concentrations were significantly reduced after IA therapy (p < 0.01 for TR-350; p < 0.04 for PH-350). There was a positive correlation between the degree of reduction of plasma proteins and the number of IA treatments given. A nonpara-metric test (Wilcoxon's signed-rank test or the Mann-Whitney test) was used for statistical analysis. We conclude from our study that IA therapy effectively lowers the plasma levels of fibrinogen, IgG, and IgM and thus can be considered a valuable alternative to other blood purification methods.     

Is the recovery profile of mivacurium independent of the rate of decay of its plasma concentration in patients with normal plasma cholinesterase activity?

Background: The duration of action of muscle relaxants is poorly correlated to the rate of decay of their plasma concentration. The plasma concentration of mivacurium may rapidly decrease below its active concentration because of the extensive hydrolysis of mivacurium. By inflating a tourniquet on one upper limb for 3 min after the administration of atracurium, mivacurium or vecuronium, we studied the influence of the initial decline of their plasma concentration on their effect. Methods: In 50 patients anaesthetised with thiopental, isoflurane and fentanyl, the effect of bolus doses of 0.15 or 0.25 mg . kg^?1 mivacurium (MIV 15, MIV 25), 0.3 or 0.5 mg . kg^?1 atracurium (ATR 30, ATR 50) and 0.06 or 0.1 mg . kg^?1 vecuronium (VEC 06, VEC 10) were measured on both arms (evoked response of the adductor pollicis to train-of-four stimulation every 12 s), a tourniquet being applied on one arm just before and during 3 min after the muscle relaxant bolus. Results: Tourniquet inflation of 3 min almost abolished the neuromuscular effect of mivacurium. In the vecuronium groups and in the ATR 50 group, tourniquet inflation did not modify the maximum degree of depression of the twitch response. Also, the duration of action of vecuronium was unaffected by the tourniquet. In the ATR 30 group, times to return of the twitch response to 25% (duration 25%) and 75% (duration 75%) of control response were significantly shorter in the cuffed arm, 23 min vs 27 min, and 41 min vs 45 min, respectively. In the ATR 50 group, only duration 25% was significantly shorter in the cuffed arm (41 min vs 45 min). Conclusion: The results suggest that the rate of decline of the plasma concentration of mivacurium is so rapid, that a very low and almost clinically ineffective concentration is present as soon as 3 min after its administration. The results also indicate that the recovery from a mivacurium-induced neuromuscular blockade is not influenced by the rate of decay of its plasma concentration in patients with genotypically normal plasma cholinesterase.     

Membranes in Artificial Organs

Abstract: Membrane processes play a pivotal and enabling role in modern replacement therapy for acute and chronic organ failure and in the management of immunologic diseases. In fact, virtually all contemporary extracorporeal blood purification methods employ membrane devices, and the next generation of artificial organs and tissue engineering therapies are almost certain to be similarly grounded in membrane technology. In this short essay, we comment on the similarities and differences among synthetic membranes and their natural counterparts and also provide a critical overview of the demographics and technology of hemodialysis, hemofiltration, apheresis, oxygenation, and emerging membrane technologies and applications.     

The multiply injured child

Blunt trauma is the principal cause of childhood death in many developed countries. This review outlines the differences between adults and children with respect to resuscitation and treatment of orthopaedic injuries in a child with polytrauma. Recent advances in techniques of fracture stabilization are reported.     

Dilemma of Membrane Biocompatibility and Reuse

Abstract: Numerous articles have been published on the multiple use of dialyzers and on the effect of different reprocessing chemicals and techniques on the dialyzer biocompatibility and performance. The results often appear contradictory, especially those comparing standard biocompatibility parameters. Despite this confusion, a discerning review of the published works allows certain limited conclusions to be drawn. Reprocessing of used hemodialyzers changes the biocompatibility profile of a dialyzer as defined by the parameters complement activation. leukopenia, and cytokine release. The effect of reprocessing depends on the chemicals and reprocessing technique applied and also on the type of membrane polymer being subjected to the reprocessing procedure. Reports of pyrogenic reactions indicate that the flux of the membrane also influences how suitable it is for safe reuse. An increased risk of allergic and pyrogenic reactions appears to be associated with dialyzer reuse. Furthermore, there has been a lack of investigations into the immunologic effect of the layer of adsorbed and chemically altered proteins that remains on the inner surface of reprocessed dialyzers. We conclude that the clinical benefit of dialyzer reuse cannot be generally accepted from a biocompatibility point of view.     

The analgesic effect of racemic ketamine in patients with chronic ischemic pain due to lower extremity arteriosclerosis obliterans

Background : Ketamine in sub-dissociative doses has been shown to have analgesic and phantom-Limb pain, where conventional treatment has often failed. Chronic ischemic pain due to lower extremity arteriosclerosis obliterans often responds poorly to analgesics, and the pain-generating mechanisms are not well understood.
Methods : Eight patients with rest pain in the lower extremity due to arteriosclerosis obliterans were given sub-dissociative doses of 0.15, 0.30, or 0.45 mg/kg racemic ketamine and morphine 10 mg as a 5-min infusion on four separate days in a cross-over, double-blind, randomised protocol. Plasma levels of (S)- and (R)-ketamine and their nor-metabolites were analysed with an enantioselective high-performance liquid chromatography (HPLC) method. Pain levels were evaluated with a visual analogue scale (VAS).
Results : Individual pain levels were highly variable during and after all the infusions but the pooled pain levels showed a dose-dependent analgesic effect of ketamine with a transient but complete pain relief in all patients at the highest dose (0.45 mg/ kg). Side-effects, mainly disturbed cognition and perception, were pronounced and dose-dependent. Morphine 10 mg had an analgesic peak at 20 min and 5/8 patients had complete pain relief. The remaining 3 patients also had high baseline pain scores, indicating a higher analgesic potency for the 0.30 and 0.45 mg/ kg ketamine doses than for morphine 10 mg.
Conclusion : We have demonstrated a potent dose-dependent analgesic effect of racemic ketamine in clinical ischemic pain. Due to a narrow therapeutic window, this analgesic effect is probably best utilised in combination with other analgesics.     

Intravenous endotoxin does not increase tissue extravasation of albumin in rats

Background : It is unclear whether activation of the inducible nitric oxide synthase (iNOS) increases or decreases the extravasation of plasma.
Methods : Chloralose anaesthetised male Wistar rats received E. coli lipopolysacharide (LPS), 3 mg kg^-1 i.v., or the corresponding volume of saline, 3 or 5 h before the end of the experiment. Mean arterial pressure (MAP) and heart rate (HR) were recorded. Tissue clearance of radio-labelled albumin, during the last 2 h of each experiment, was determined by a double-isotope method. In separate animals, the serum concentration of nitrite and nitrate was determined, 5 h after LPS or the solvent.
Main Results : LPS initially decreased MAP and lastingly increased HR. In the 3-h LPS animals (n=8), tissue plasma clearance was lower in the heart and calf muscle and increased only in diaphragm, compared to corresponding control animals (n=8). In the 5-h LPS rats, clearance was lowered (n=8) in the entire gastrointestinal tract and in testes, compared to controls (n=8). The serum nitrite/nitrate concentration was higher in animals given LPS (n=6) than in controls (n=6).
Conclusion : After LPS, tissue clearance of albumin was not increased in any major tissue, in spite of increased serum levels of NO end products. Apparently, after activation of iNOS, the augmented release of NO is not necessarily associated with increased albumin extravasation.     

Adrenaline markedly improves thoracic epidural analgesia produced by a low-dose infusion of bupivacaine, fentanyl and adrenaline after major surgery: A randomised, double-blind, cross-over study with and without adrenaline

Background: Basic pharmacological research indicates that there are synergistic antinociceptive effects at the spinal cord level between adrenaline, fentanyl and bupivacaine. Our clinical experience with such a mixture in a thoracic epidural infusion after major surgery confirms this. The objectives of the present study were to evaluate the effects on postoperative pain intensity, pain relief and side effects when removing adrenaline from this triple epidural mixture. Methods: A prospective, randomised, double-blind, cross-over study was carried out in 24 patients after major thoracic or abdominal surgery. Patients with only mild pain when coughing during a titrated thoracic epidural infusion of about 10 ml · h^?1 of bupivacaine 1 mg · ml^?1, fentanyl 2 μg · ml^?1, and adrenaline 2 μg · ml^?1 were included. On the 1^st and 2^nd postoperative days each patient was given a double-blind epidural infusion, at the same rate, with or without adrenaline. The effect was observed for 4 h or until pain when coughing became unacceptable in spite of a rescue analgesic procedure. Rescue analgesia consisted of up to two epidural bolus injections per hour and i.v. morphine if necessary. All patients received rectal paracetamol 1 g, every 8 h. Fentanyl serum concentrations were measured with a radioimmunoassay technique at the start and end of each study period. Main outcome measures were extent of sensory blockade and pain intensity at rest and when coughing, evaluated by a visual analogue scale, a verbal categorical rating scale, the Prince Henry Hospital pain score, and an overall quality of pain relief score. Results: The number of hypaesthetic dermatomal segments decreased (P <0.001) and pain intensity at rest and when coughing increased (P <0.001) when adrenaline was omitted from the triple epidural mixture. This change started within the first hour after removing adrenaline. After 3 h pain intensity when coughing had increased to unacceptable levels in spite of rescue analgesia (epidural bolus injections and i.v. morphine). Within 15–20 min after restarting the triple epidural mixture with adrenaline, pain intensity was again reduced to mild pain when coughing. Serum concentration of fentanyl doubled from 0.22 to 0.45 ng · ml^?1 (P <0.01), and there was more sedation during the period without adrenaline. Conclusions: Adrenaline increases sensory block and improves the pain-relieving effect of a mixture of bupivacaine and fentanyl infused epidurally at a thoracic level after major thoracic or abdominal surgery. Serum fentanyl concentrations doubled and sedation increased when adrenaline was removed from the epidural infusion, indicating more rapid vascular absorption and systemic effects of fentanyl.