免疫磁珠法分离胆囊癌CD133阳性细胞及其生物学特性鉴定

目的 建立胆囊癌CD133+细胞分离纯化的方法,观察胆囊癌CD133+细胞和CD133-细胞生物学特性的差异.方法 流式细胞仪检测胆囊癌GBC-SD、SGC996细胞中CD133所占百分比,免疫磁珠法分选CD133+细胞亚群,免疫荧光法定位检测CD133蛋白表达,逆转录-聚合酶链反应(RT-PCR)检测CD133 mRNA表达,细胞计数试剂盒(CCK-8)法检测CD133+组和CD133-组细胞增殖能力及对5-氟尿嘧啶(5-Fu)耐药特性的差异,单克隆形成实验观察单个CD133+细胞生长特性.结果 胆囊癌GBC-SD、SGC996细胞中CD133+亚群所占相对百分比为(68.5±2.9)％、(0.3±0.2)％.GBC-SD组CD133 mRNA相对灰度值(0.6466±0.0259)显著高于SGC996组(0.2181±0.0108,P＜0.01).CD133蛋白定位于细胞膜表面,并在GBC-SD细胞中呈强表达.人胆囊癌GBC-SD细胞分选后,CD133+组CD133蛋白表达明显强于CD133-组.CD133+组中CD133+亚群所占比例为(90.4±0.9)％.CD133+组CD133mRNA相对灰度值(0.7734±0.0217)显著高于CD133-组(0.2146 ±0.0174,P＜0.01).CD133+组细胞增殖能力明显强于CD133-组(P＜0.01).经5-Fu(0.1μg/ml)处理后,CD133+组细胞生存率明显高于CD133-组(P＜0.05).单克隆形成实验结果示单个CD133+细胞可形成新的细胞克隆,且CD133+组[(36.25±2.99)％]细胞克隆球形成率高于CD133-组[(4.50±1.29)％,P＜0.01].体内成瘤实验结果示CD133+组与未分选组移植成瘤率分别为100％和60％,而CD133-组不成瘤.结论 免疫磁珠分选系统可成功分离高纯度的胆囊癌CD133+细胞,而且人胆囊癌CD133+细胞具有一定的增殖、耐药、自我更新及致瘤潜能.     

胃癌CD133阳性细胞亚群肿瘤起始细胞样特性的检测

目的 探讨人胃癌细胞CD133＋亚群的分选及其特性的鉴定.方法 对50例胃癌原发灶和癌旁胃黏膜组织标本行免疫组织化学染色及Western blot检测CD133蛋白的表达.采用流式细胞仪检测不同分化胃癌细胞系CD133所占百分比,免疫磁珠法分选CD133＋细胞亚群,悬浮培养并观察其生长特性,并检测CD133阳性细胞裸鼠皮下接种致瘤能力.单细胞克隆观察单个CD133＋细胞生长特性,半定量反转录聚合酶链反应法鉴定相关干细胞标记的表达.结果 CD133蛋白多定位于胃癌原发灶黏膜及黏膜下层的肿瘤细胞膜表面,其相对表达量高于癌旁胃黏膜组织（P＜0.05）.不同分化程度的人胃癌细胞系KATO-Ⅲ、SGC-7901、AGS及MKN-45中CD 133＋亚群所占相对百分比为（28±2）％、（17±2）％、（6±2）％及（4±2）％.人胃癌细胞系KATO-Ⅲ分选后阳性组中CD133＋亚群比例分别为（91±3）％;培养1周后,达到（95±2）％,并不断增殖形成细胞球.而且其增殖能力强于阴性细胞[群体倍增时间分别为（21±3）h和（40±8）h,P＜0.05].CD133阳性组和未分选组细胞裸鼠皮下接种时成瘤率分别为100％和80％;而CD133阴性组不成瘤,CD133阳性组移植瘤平均体积及重量均大于未分选组（P＜0.05,P＜0.05）.单克隆形成实验示单个CD133＋细胞可形成新的细胞克隆.半定量RT-PCR检测示其表达干细胞标记物Oct-4、Nanog、Sox-2、Musashi-1及EGFR.结论 体外可成功分离、纯化和扩增人胃癌细胞CD133＋亚群,其具有自我更新、增殖能力及较强的致瘤能力,并表达部分干细胞相关基因.     

化疗药物对胃癌CD133+细胞亚群的作用及其对相关凋亡基因表达的影响

目的 研究常规化疗药物对纯化的胃癌CD133+细胞亚群的作用及对相关凋亡基因Bcl-2和BAX的mRNA表达的影响,进而探讨胃癌耐药的作用机制.方法 采用免疫磁珠分选术分离纯化KATO-Ⅲ细胞株中CD133+和CD133细胞亚群.采用CCK-8法分析两种亚群细胞对不同化疗药物5-氟尿嘧啶(5-FU)、顺铂及依托泊苷(VP-16)敏感性的差别.行半定量聚合酶链反应分析化疗药物诱导后相关凋亡基因表达产物的表达差异.结果 KATO-Ⅲ细胞磁珠分选纯化后,经流式细胞仪分析结果显示:分选后CDI33+组所得细胞CD133+表达率为90％.5-FU、顺铂及VP-16分别作用12h后,CD133+组及CD133-组均开始出现凋亡的形态学改变.CCK-8检测发现CD133+组细胞生长抑制比率较CD133-组有一定程度的下降[5-FU组为:(30.56±1.99)％ ～ (88.60±1.95)％ vs(32.81±2.67)％ ～ (35.55±3.23)％,P =0.045;顺铂组为:(45.89±3.64)％ ～ (81.20±1.18)％ vs(50.21 ±3.22)％ ～(90.46±1.89)％,P=0.043; VP-16组为:(37.21±3.80)％ ～ (78.49±3.22)％ vs (35.55±3.23)％ ～ (89.32±3.54)％,P=0.048].3种化疗药物干预后,两组亚群细胞中均呈现凋亡抑制因子Bcl-2 mRNA表达降低,凋亡因子BAXmRNA表达升高.这些变化在CD133+组中较CD133组中更为明显.结论 胃癌CD133+细胞亚群对5-FU、顺铂及VP-16具有一定耐药潜能.可能是由于BAX基因上调及Bcl-2基因下调进而诱导胃癌CD133+细胞亚群凋亡,并由此而获得对肿瘤药物的抵抗性.     

CD44+-ESA+在结肠癌干细胞分选中的应用

目的 分选结肠癌细胞株SW480细胞中的CD133+-CD44+-ESA+亚群细胞,并观察其致瘤性.方法 用流式细胞仪分选SW480细胞中CD133+-CD44+-ESA+、CD133--CD44+-ESA+及CD133--CD44--ESA-亚群细胞.将这3组细胞分别接种于NOD/SCID小鼠,每组5只,观察肿瘤生长...     

胆管癌干细胞的分离、培养及鉴定

目的:从人胆管癌细胞系QBC-939中分离具有干细胞特征的肿瘤细胞,为后续胆管癌干细胞的研究提供材料。方法:用无血清培养法及流式细胞分选法从QBC-939细胞中分离得到具有干细胞特征的CD133+Ep CAM~(high)干细胞样细胞,继续在无血清培养基中培养,观察其成球能力,并比较CD133+Ep CAM~(high)干细胞样细胞与QBC-939细胞单克隆形成率、耐药性,增殖能力,干细胞相关核转录因子OCT-4、Bmi-1、E-cadherin蛋白表达情况,以及BALB/c小鼠皮下移植后的成瘤能力。结果:在无血清培养基中,CD133+Ep CAM~(high)干细胞样细胞具有较强的成球能力。与QBC-939细胞比较,CD133+Ep CAM~(high)干细胞样细胞克隆形成率、洛铂耐药性、增殖明显增加;干细胞相关核转录因子OCT-4、Bmi-1表达明显增加,而E-cadherin表达明显降低;皮下移植瘤形成率明显增加。以上差异均有统计学意义(均P0.05)。结论:从人胆管癌QBC-939细胞中分离的干细胞样细胞具有肿瘤干细胞特性,可用于胆管癌干细胞的研究。     

人结直肠癌干细胞休眠与增殖阶段细胞形态学的研究

目的初步研究人结直肠癌干细胞休眠与增殖阶段细胞形态的变化。方法流式细胞仪从新鲜人结直肠癌组织中分选EpCAMhigh／CD44＋／CD133＋细胞亚群,并通过裸鼠（NOD／SCID）成瘤实验鉴定其干细胞特性：采用三维培养,WST．1绘制人结直肠癌干细胞的生长曲线;流式细胞仪测定P27及Ki一67的表达水平,区分人结直肠癌干细胞休眠和增殖时相;细胞免疫荧光显示休眠期与增殖期人结直肠癌干细胞形态的变化。结果EpCAMhigh／CD44＋／CDl33‘细胞亚群在人结直肠癌组织中占1．6％．经NOD／SCID成瘤实验证实为人结直肠癌干细胞。人结直肠癌干细胞生长曲线呈“S”型;前3d生长缓慢,细胞为静止阶段（休眠期）,P27表达水平逐渐增加,Ki．67表达偏低;从第4d开始,细胞进入增殖期,Ki-67表达逐渐增加,P27表达降低。细胞免疫荧光染色显示：休眠期人结直肠癌干细胞圆而大,伪足少;而增殖期细胞伪足增多,呈现增殖和侵袭的状态。结论肿瘤的复发、转移可能与肿瘤干细胞的生长状态发生改变有一定关系;人结直肠癌干细胞增殖期与休眠期相比。呈现出明显增殖和侵袭能力：这为治疗人结直肠癌及其他肿瘤的复发和转移提供了新的切人点。     

Notch信号通路在肺癌干细胞中的表达及其对增殖的影响

目的 观察Notch信号通路在肺癌干细胞中的表达及阻断Notch信号通路对肺癌干细胞增殖的影响.方法 以CD133作为肿瘤干细胞表面标志,采用流式细胞仪高速分选技术从人肺腺癌细胞株A549中分离肺癌干细胞及普通肿瘤细胞,实时荧光定量聚合酶链反应(FQ-PCR)及Western blot检测肺癌干细胞和普通肿瘤细胞内的Notch信号通路的表达水平;细胞计数试剂盒(CCK-8)检测肺癌干细胞和普通肿瘤细胞的体外增殖能力,并绘制生长曲线;使用γ-分泌酶抑制剂(DAPT)阻断Notch信号通路传导,观察肺癌干细胞和普通肿瘤细胞的体外生长差异.结果 流式分选前检测CD133阳性细胞(肺癌干细胞)占所有A549细胞的百分比为(0.40±0.11)％,而流式分选后所得细胞中,CD133阳性细胞占百分比为(95.00±0.63)％,两者差异有统计学意义(P＜0.01).Notch通路在肺癌干细胞及普通肿瘤细胞中均表达,Notch1及Notch2在肺癌干细胞中的表达显著低于在普通肿瘤细胞内的表达,差异有统计学意义(P ＜0.05);Hes1仅在普通肿瘤细胞中表达,在肺癌干细胞中未检测到表达.肺癌干细胞与普通肿瘤细胞的增殖能力差异无统计学意义(P＞0.05),而在DAPT干预48 h后,肺癌干细胞和普通肿瘤细胞的体外增殖均受到了抑制,肺癌干细胞的生长抑制率[(33.7±1.9)％]显著高于普通肿瘤细胞的生长抑制率[(21.5±3.4)％],差异有统计学意义(P＜0.05).结论 较之普通肿瘤细胞,阻断Notch通路传导对肺癌干细胞的生长抑制效果更强,这可能与DAPT抑制了Notch的过高表达对肺癌细胞的负反馈作用有关.     

胰腺癌肿瘤干细胞对抗肿瘤药物敏感性的实验研究

目的 探讨胰腺癌肿瘤干细胞对抗肿瘤药物的敏感性.方法 FACS技术分选人胰腺癌PANC-1细胞;RT-PCR技术检测分选PANC-1细胞中CD133、ABCG2、Notch1的表达情况;MTT法检测分选细胞对抗肿瘤药物5-氟尿嘧啶和吉西他滨的耐药性.建立分选细胞的移植瘤模型,随机分为吉西他滨治疗组(n=3)和对照组(n=3),观察肿瘤生长情况,作CD133免疫组化染色.结果PANC-1细胞中含有SP亚群.SP细胞CD133、ABCG2、Notch1的mRNA的表达明显上调,non-SP细胞的表达量显著低于前者.在吉西他滨的干预下,SP细胞和non-SP细胞的OD值差异有统计学意义.而5-氟尿嘧啶的干预(10 μg/ml和100 μg/ml)则没有显著差异.移植肿瘤治疗组中CD133阳性细胞明显多于对照组(P=0.001).结论胰腺癌中存在SP亚群细胞.胰腺癌PANC-1的成瘤能力是由其中的SP亚群细胞决定的,而并非所有胰腺癌PANC-1细胞.胰腺癌肿瘤干细胞对抗肿瘤药吉西他滨具有较高耐药性.     

树突状细胞瘤苗联合吉西他滨对肝癌干细胞的杀伤效应

目的:探讨负载CD133+肝癌细胞抗原的树突状细胞(DC)联合吉西他滨(GEM)在体外对肝癌干细胞的杀伤效应。方法:取对数生长期的人肝癌细胞系Huh-7以CD133作为分子标志进行流式分选,得到肝癌干细胞。将人外周血单个核细胞(PBMC)在体外诱导分化为树突状细胞(DC)。DC负载Huh-7细胞和CD133+细胞抗原后与T细胞共育得到特异性细胞毒性T细胞,将CD133+细胞作为靶细胞进行细胞毒性试验。实验组按处理因素分为:GEM组,CD133+-CTL组,GEM+CD133+-CTL组,Huh7-CTL组和GEM+Huh7-CTL组。CCK-8法检测杀伤率,然后比较各组间差异。结果:对CD133+细胞的杀伤效应以GEM+CD133+-CTL组最强,与其他各组比较差异均有统计学意义(P0.05)。单独就DC瘤苗杀伤率,CD133+-CTL组高于Huh7-CTL组(P0.05)。结论:CD133+肝癌干细胞裂解产物致敏的DC瘤苗联合化疗药物可以有效杀伤肝癌干细胞,进而可能降低肝癌术后和肝癌肝移植后的转移和复发率。     

人胰腺癌干细胞差异性基因的表达

目的 分选、鉴定人胰腺癌干细胞,运用基因芯片技术分析其差异性基因的表达.方法 运用流式分选技术分选胰腺癌干细胞(CD24+CD44+ESA+),NOD/SCID鼠移植瘤试验进行肿瘤干细胞特性鉴定.采用Affymetrix U133 plus2.0人类全基因组表达谱芯片对胰腺癌干细胞和非干细胞进行差异基因筛选.结果 分选得到人胰腺癌CD24+CD44+ESA+亚群细胞,占所有细胞的0.8%;5×103个CD24+CD44+ESA+细胞就能成瘤(2/4),而阴性细胞1×105才能成瘤(1/4);CD24+CD44+ESA+具有一定的自我更新和分化能力.基因芯片杂交获得6553(11.99%)条差异基因,胰腺癌干细胞中5255(9.61%)条上调表达,1298(2.37%)条下调表达.其中差异基因涉及细胞凋亡、细胞周期、代谢、细胞线粒体结构和耐药等多个方面.结论 胰腺癌于细胞具有自身特征性基因表达谱,为进一步从干细胞层面研究胰腺癌发病机制及靶向治疗奠定基础.     

Vasopressor hormone response following mesenteric traction during major abdominal surgery

Background : We investigated the vasopressor hormone response following mesenteric traction (MT) with hypotension due to prostacyclin (PGI₂) release in patients undergoing abdominal surgery with a combined general and epidural anesthesia. Methods : In a prospective, randomized, placebo-controlled study we administered 400 mg ibuprofen (i.v.) in 42 patients scheduled for abdominal surgery. General anesthesia was combined with epidural anesthesia (T4-L1). Before as well as 5, 15, 30, 45, and 90 min after MT we recorded plasma osmolality, hemodynamics and measured 6-keto-PGFlα (stabile metabolite of PGI₂), TXB₂ (stabile metabolite of thromboxane A₂) active renin, and arginine vasopressin (AVP) plasma concentrations by radioimmunoassay. Catecholamine levels were assessed by high-pressure liquid chromatography (HPLC) with electrochemical detection. Results : Following MT, arterial hypotension occurred along with a substantial PGI₂ release. This was completely abolished by ibuprofen administration. Although plasma levels of 6-keto-PGF_1α (1133 (708) vs. 60 (3) ng/L, median (median absolute deviation), P=0.0001, placebo vs. ibuprofen) remained significantly elevated, blood pressure was restored within 30 min after MT in the placebo group. At the same point in time plasma concentrations of TXB² (164 (87) vs. 58 (1) ng/L, P=0.0001), epinephrine (46 (33) vs. 14 (6) ng/L, P=0.001), AVP (41 ± (18) vs. 12 (7) ng/L, P=0.0004), and active renin (27 (12) vs. 12 (4) ng/L, P = 0.001) were significantly higher in placebo-treated patients. Conclusion : Under combined general and epidural anesthesia arterial hypotension following MT due to endogenous PGI₂ release is associated with enhanced release of AVP, active renin, epinephrine and thromboxane A₂, presumably contributing to hemodynamic stability within 30 min after MT.     

A comparison of the inhibitory effects of four volatile anaesthetics on the metabolism of chlorzoxazone, a substrate for CYP2E1, in rabbits

Background: Halothane inhibits in vitro and in vivo activity of cytochrome P-450 (CYP) 2E1. There are several fluorinated volatile anaesthetics besides halothane, and most of them are defluorinated by CYP2E1. It is unclear whether other fluorinated anaesthetics inhibit the in vivo activity of CYP2E1.
Methods: We compared the inhibitory effects of therapeutic concentrations of four inhalational anaesthetics, halothane, enflurane, isoflurane, and sevoflurane, on chlorzoxazone metabolism in rabbits receiving artificial ventilation.
Results: All four inhalational anaesthetics decreased arterial blood pressure and increased plasma chlorzoxazone concentration. However, no significant differences in the plasma chlorzoxazone concentration were found between the four anaesthetics. The estimated chlorzoxazone clearance increased after beginning inhalation with all four agents, but no significant difference in clearance was noted between agents.
Conclusions: At therapeutic concentrations, the in vivo inhibitory effect on chlorzoxazone metabolism was similar for all four inhalational anaesthetics examined, even though their chemical characteristics and extent of hepatic metabolism differ considerably.     

Microspheres Based Detoxification System: A New Method in Convective Blood Purification

Abstract: A variety of protein-bound or hydrophobic substances, accumulating as a result of pathologic conditions such as exogenous or endogenous intoxications, are removed poorly by conventional detoxification methods because of low accessibility (hemodialysis), insufficient adsorption capabilities (hemosorption), low efficiency (peritoneal dialysis), or economic limitations (high-volume plasmapheresis). Combining advantages of existing methods with microspheric technology, a module-based system was designed. Major operating parameters of the latter can be modified to allow for adjustment to individual clinical situations. An extracorporeal blood circuit including a plasmafilter is combined with a secondary high-velocity plasma circuit driven by a centrifugal pump. Different microspheric adsorbers can be combined in one circuit or applied in sequence. Thus, a prolonged treatment can be tailored using specially designed selective adsorber materials. Comparing this system with existing methods (high-flux hemodialysis, molecular adsorbent recycling system), results from our in vitro studies and animal experiments demonstrate the superior efficiency of substance removal.     

Bariatric Surgery in Some "Central and East-European (former Eastern bloc)"Countries - Current Status and Prediction for the Next Millennium

Background: Obesity is increasing globallly, including in the formerly "Eastern Bloc" countries. Methods: A survey was made of obesity and bariatric surgery. Results: In the 8 East and Central European countries studied, with total population 300 million, roughly 43% of the population was overweight (BMI 25-30), 23% obese (BMI > 30), with about 15 million people morbidly obese (BMI > 40). From 0-10 morbidly obese individuals/100,000/year undergo bariatric surgery. Conclusion: Most countries were found to provide inadequate treatment for obesity.The majority of the morbidly obese are not treated effectively. However, health-care awareness of obesity and bariatric surgeons are slowly increasing.     

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.     

Influence of dopexamine hydrochloride on haemodynamics and regulators of circulation in patients undergoing major abdominal surgery

Background: Catecholaminergic support is often used to improve haemodynamics in patients undergoing major abdominal surgery. Dopexamine is a synthetic vasoactive catecholamine with beneficial microcirculatory properties. Methods: The influence of perioperative administration of dopexamine on cardiorespiratory data and important regulators of macro- and microcirculation were studied in 30 patients undergoing Whipple pancreaticduodenectomy. The patients received randomized and blinded either 2 μg · kg^?1 · min^?1 of dopexamine (n=15) or placebo (n=15, control group). The infusion was started after induction of anaesthesia and continued until the morning of the first postoperative day. Endothelin-1 (ET-1), vasopressin, atrial natriuretic peptide (ANP), and catecholamine plasma levels were measured from arterial blood samples. Measurements were carried out after induction of anaesthesia, 2 h after onset of surgery, at the end of surgery, 2 h after surgery, and on the morning of the first postoperative day. Results: Cardiac index (CI) increased significantly in the dopexamine group (from 2.61±0.41 to 4.57±0.78 1 · min^?1 · m^?2) and remained elevated until the morning of the first postoperative day. Oxygen delivery index (DO₂I) and oxygen consumption index (VO₂I) were also significantly increased in the dopexamine group (DO₂I: from 416±91 to 717±110 ml/m² · m²; VO₂I: from 98±25 to 157±22 ml/m² · m²), being significantly higher than in the control group. pHi remained stable only in the dopexamine patients, indicating adequate splanchnic perfusion. Vasopressive regulators of circulation increased significantly only in the untreated control patients (vasopressin: from 4.37±1.1 to 35.9±12.1 pg/ml; ET-1: from 2.88±0.91 to 6.91±1.20 pg/ml). Conclusion: Patients undergoing major abdominal surgery may profit from prophylactic perioperative administration of dopexamine hydrochloride in the form of improved haemodynamics and oxygenation as well as beneficial influence on important regulators of organ blood flow.     

Synergistic interaction between the effects of propofol and midazolam with fentanyl on phrenic nerve activity in rabbits

Background: It has been shown that the depressive effects of both propofol and midazolam on consciousness are synergistic with opioids, but the nature of their interactions on other physiological systems, e. g. respiration, has not been fully investigated. The present study examined the effect of propofol and midazolam alone and in combination with fentanyl on phrenic nerve activity (PNA) and whether such interactions are additive or synergistic. Methods: PNA was recorded in 27 anaesthetised and artificially ventilated rabbits. In three groups, propofol, fentanyl and midazolam were administered intravenously in incremental doses to construct dose-response curves for the depressant effects of each one on PNA. In another two groups, the effect of pretreatment with either fentanyl 1 μg · kg^?1 i. v. or midazolam 0.05 mg · kg^?1 i. v. on the effects of propofol and fentanyl respectively on PNA were studied. Results: Propofol and fentanyl caused a dose-dependent depression of PNA with complete abolition at the highest total doses of 16 mg · kg^?1 i. v. and 32 μg · kg^?1 i. v., respectively. In contrast, midazolam in incremental doses to a total of 0.8 mg · kg^?1 reduced mean PNA by 63%, but approximately 12% of PNA remained at a total dose as high as 6.4 mg · kg^?1. The mean ED₅₀s, calculated from dose-response curves, were 5.4 mg · kg^?1, 3.9 μg · kg^?1 and 0.4 mg · kg^?1 for propofol, fentanyl and midazolam, respectively. Initial doses of either fentanyl 1 μg · kg^?1 i. v. or midazolam 0.05 mg · kg^?1 i. v. acted synergistically with subsequent doses of either propofol or fentanyl to abolish PNA at total doses of 8 mg · kg^?1 and 8 μg · kg^?1, respectively. Conclusion: Fentanyl has a synergistic interaction with both propofol and midazolam on PNA and hence potentially on respiration.     

Intrathecal administration of sameridine to patients subjected to arthroscopic knee joint surgery

Background: Sameridine, a new substance with both local anesthetic and opioid effects, was administered intrathecally for the first time to humans, i. e. in patients subjected to arthroscopic knee joint surgery.
Method: A dose-escalating (10, 15, 20 and 25 mg), open study was performed in 33 patients. Only two patients were included in the 25 mg group.
Results: Sameridine provided good quality of surgical anesthesia in all patients except those receiving 10 mg. The maximum level of sensory block, Th5–Th7, was reached within 30 min with a median duration of 3.6–3.9 h. The motor block was more profound with increasing dose, but never lasted longer than the sensory block. The influence on heart rate and blood pressure was minor and atropine and ephedrine were needed in four patients. No clinically significant ECG-changes were detected and no arrhythmias were recorded. Oxygen saturation and respiratory rate did not decrease in a clinically significant way and were not affected by concomitant morphine given i. v. postoperatively. There were few side-effects, the most frequent being mild pruritus (10/33).
Conclusion: Sameridine provided clinically adequate anesthesia for the patients receiving the doses of 15, 20 and 25 mg. Further studies are needed to evaluate the substance and it is of great interest to clinically investigate the opioid component with respect to postoperative analgesia.     

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.