P选择素在肾病综合征并发深静脉血栓中的作用及犬血栓模型磁共振分子成像观察

目的 观察P选择素在肾病综合征（NS）并发深静脉血栓形成（DVT）中作用，探讨P选择素靶向对比剂及分子磁共振成像（MRI）在DVT犬模型早期诊断应用的可行性。 方法 （1）选择我院2005年至2006年间住院NS患者41例，根据核素深静脉造影检查有无伴发DVT，再分为DVT组和无DVT组，检测患者血中P选择素含量。（2）选择健康成年毕格犬，建立DVT模型，并按造模即刻、1 h、3 h采血并取静脉损伤节段，行血管组织和血中P选择素含量检测。（3）利用研制的抗P选择素单抗，制成P选择素靶向对比剂，结合体外犬静脉损伤节段血管MRI，进行犬活体内观察。 结果 （1）NS患者血P选择素水平较健康组显著增高（P < 0.01），DVT组又较无伴DVT组明显增高（P < 0.01）。（2）模型犬血P选择素水平较对照犬显著增高（P < 0.05），且于受损血管内膜及血栓形成部位明显表达。（3）制备的MRI对比剂，体外可明显增强犬离体受损血管与血栓部位显像信号。体内于犬静脉损伤局部注射对比剂30 min，MRI即显示高于周围肌肉显影的血管信号；1 h可见附壁血栓增强信号；至3 h随血栓形成增大而持续强化，实验组对比度噪声比 （CNR）值与对照组比较，差异有统计学意义（11.51±2.32比2.71±0.86，P < 0.01），且显示了与P选择素表达一致的信号强化效果。另从犬损伤部位远心端注射对比剂30 min至1 h，也显示了上述成像效果；2 h至4 h血栓信号由明显上升渐见趋缓，延迟24 h信号强度减弱，实验组CNR值与对照组间差异也有统计学意义（10.40±2.15比1.93±0.57，P < 0.01）。此外，该对比剂对实验犬的生命体征及心、肺、肝、肾等脏器均无明显影响。 结论 P选择素参与NS合并DVT。利用P选择素单抗MRI对比剂，可在活体内早期定位显像及反映血栓形成状态，为DVT早期诊断提供了一种可行方法。     

腰椎间盘退变性疾患下腰椎终板形态的MRI观察

【摘要】　目的：在MRI片上观察腰椎间盘退变患者下腰椎终板形态的分布规律,分析终板形态和椎间盘退变的关系。方法：回顾分析两组腰椎间盘退变性疾病患者的术前腰椎MRI,A组110例为单节段腰椎间盘突出症患者,B组35例为椎间盘源性腰痛患者。根据正中矢状面MRI T1像,将终板形态分为凹面、平坦、不规则三型;根据Pfirrmann法评定椎间盘退变程度并将Ⅰ～Ⅴ级分别计为1～5分;按Modic改变分级标准判定各节段终板有无Modic改变。分析下腰椎终板的形态特点及三种分型与椎间盘退变程度、Modic改变等的关系。结果：①435个下腰椎节段中,凹面型终板最多（215/435）,A组中占50.6％（167/330）,B组中占45.7％（48/105）,且主要分布于L3/4（108/215）、L4/5（83/215）节段;平坦型终板占29.0％（126/435）,并主要位于L5/S1节段（76/126）;不规则型终板最少（94/435）,A组中占23.0％（76/330）,B组中占17.1％（18/105）,也主要位于L5/S1节段（45/94）。②A组患者中,凹面型终板退变程度平均为3.31±0.81分,平坦型为3.66±0.64分,不规则型为4.16±0.67分,两两比较有显著差异（P＜0.05）;椎间盘突出节段以平坦型（37/110）和不规则型（43/110）终板占多数,无突出节段则以凹面型（137/220）终板占多数,差异有显著性（P＜0.05）;不规则型终板比凹面型和平坦型更容易伴发Modic改变,差异有显著性（P＜0.05）,凹面型和平坦型间无显著性差异（P＞0.05）。③B组患者中,凹面型终板的椎间盘退变程度平均为3.23±0.86分,平坦型为3.54±0.85分,不规则型为3.94±0.54分,仅凹面型和不规则型间差异有显著性（P＜0.05）。④相同终板形态时A组和B组椎间盘退变程度相比均无显著性差异（P＞0.05）。结论：终板形态与椎间盘退变、Modic改变之间有相关性。终板形态由凹面型到平坦型再到不规则型,腰椎间盘退变程度逐渐加重。影像学上终板形态改变在一定程度上反映了椎间盘退变的程度。     

腰椎间盘退变性疾病中Modic改变的相关研究进展

1987年Roos等率先报道在腰椎间盘退变性疾病患者的MRI中发现邻近终板区域的椎体信号改变.1988年Modic等系统描述了存退变的腰椎间盘终板及终板下骨质MRI信号改变的类型、分型标准及组织学变化.随着MRI在腰椎退变性疾病诊断中的应用.广大学者将腰椎间盘退变性疾病（degenerative disc diseases,DDD）中终板及终板下骨质MRI信号的改变称之为Modic改变.近年来对Modic改变的研究方兴未艾,现将相关研究进展综述如下.     

腰椎间盘脱出并肉芽组织增生的MRI诊断及临床意义

目的 探讨MRI对椎间盘脱出并肉芽组织增生的诊断及临床应用价值。方法 将T2WI示脱出髓核周围和其内高信号影27例患者行MRI增强扫描,分析其表现及特点。结果 27例共30个腰椎间盘脱出,脱出髓核与硬脊膜分界模糊9个,部分分界清楚21个,增强扫描髓核周围线样强化6个,带状强化24个,17个与患侧神经根粘连。6个脱出髓核内信号稍减低,8个信号稍增高,5个明显增高,11个呈等信号,增强扫描髓核无强化26个,斑片状强化4个。结论 MRI能准确诊断腰椎间盘脱出及肉芽组织增生。     

老年腰椎结核合并骨质疏松患者麻醉诱导应用顺式阿曲库铵的药效学研究

目的 比较老年腰椎结核合并骨质疏松患者与普通老年腰椎手术患者麻醉诱导时顺式阿曲库铵药效学的差异。方法 选择2012年6月~2013年6月我院骨科老年腰椎结核合并骨质疏松患者（A组）、老年腰椎手术合并骨质疏松的患者（B组）,老年腰椎结核手术患者（C组）和腰椎间盘突出手术患者（D组）各20例进行研究。所有患者均于术前30min肌肉注射阿托品0.5mg。4组患者麻醉诱导均采用静脉注射咪达唑仑0.05mg/kg、丙泊酚2mg/kg、芬太尼5μg/kg和注射单次剂量顺式阿曲库0.15mg/ kg,观察记录诱导期间患者血流动力学变化,同时应用肌松监测仪记录各组起效时间、第一次肌颤搐刺激T1恢复到25%、75%、90%的时间及恢复指数。结果 诱导期间A、B、C、D各组之间的血压、心率变化及肌松药的起效时间之间的差异无统计学意义(P >0.05),A组注射相同剂量的顺式阿曲库铵后神经肌肉阻滞的25%、75%、90%的恢复时间为34.1±9.5min,45.7±5.6 min,51.8±5.1 min;B组注射相同剂量的顺式阿曲库铵后神经肌肉阻滞的25%、75%、90%的恢复时间为32.2±7.4 min,62.4±2.7 min,63.1±6.4 min;C组注射相同剂量的顺式阿曲库铵后神经肌肉阻滞的25%、75%、90%的恢复时间为33.5±5.4 min,43.6±6.1 min, 49.9±6.7 min;D组注射相同剂量的顺式阿曲库铵后神经肌肉阻滞的25%、75%、90%的恢复时间为44.1±7.0 min,58.7±7.6 min,64.9±5.3 min。A组较B、D组的恢复时间显著缩短(P <0.05)。 而A组注射相同剂量的顺式阿曲库铵后神经肌肉阻滞的恢复时间与C组之间差异无统计学意义(P >0.05)。结论 腰椎结核患者麻醉诱导时应用顺式阿曲库铵可显著降低其作用时间,而单纯骨质疏松患者麻醉诱导时不会影响应用顺式阿曲库铵的作用时间。     

腰椎间盘脱出症中后纵韧带破裂的MRI诊断

目的：探讨腰椎间盘脱出症中后纵韧带破裂的MRI诊断及其临床意义。方法：选取55例（56个椎间隙）经手术证实为腰椎间盘脱出症伴后纵韧带破裂患者,对其术前的MRI片进行回顾性分析研究。结合后纵韧带低信号线的完整性、脱出髓核的大小及移位的方向等MRI表现,观察MRI诊断后纵韧带破裂的正确性。结果：腰椎后纵韧带在MRI所有序列上都表现为一细低信号线,判断后纵韧带破裂的最可靠的征象是椎间盘外围低信号线的缺损、中断或消失。脱出髓核的前后径为6.0～13.5mm,上下径为4.1～44mm,轴位像显示27个脱出髓核面积大于椎管横断面的50%,29个小于50%。脱出髓核向后上方移位12个,移位距离为6.3～16.5mm;向后下方移位36个,移位距离为7.2～39mm;水平后移8个。本组55例（56个）腰椎间盘脱出症患者中,MRI矢状位T1加权图像上,有51个（91.1%）可诊断为后纵韧带破裂者;矢状位T2加权图像上,有49个（87.5%）可见后纵韧带破裂;轴位T2加权图像上,有50个（89.3%）可见后纵韧带破裂。结论：综合观察分析后纵韧带低信号线的完整性、脱出髓核的大小及其移位的方向等MRI的征象,能明显提高MRI对后纵韧带破裂诊断的正确率,对治疗方法的选择有重要的临床意义。     

终板下椎体缺血诱导兔椎间盘退行性变模型的建立及终板中内皮素1的表达

目的通过终板下注射无水乙醇阻碍椎体-终板营养,建立一种新型兔腰椎椎间盘退行性变模型,并观察终板退行性变过程中内皮素1(ET-1)的表达情况。方法健康4月龄新西兰兔32只,随机分成4组,每组8只,选取L5,6椎体(对应L4/L5及L5/L6椎间盘)注射300μL无水乙醇,选取L4椎体(对应L3/L4椎间盘)注射磷酸盐缓冲液(PBS)作为实验对照,L7椎体(对应L6/L7椎间盘)未注入任何物质作为正常对照。其中1组造模后1个月提取软骨终板细胞,行免疫细胞化学染色检测ET-1表达;余3组分别于造模后1、3和5个月进行椎间盘X线和MRI检查,取椎间盘组织行HE染色观察形态学改变,免疫组织化学染色观察ET-1表达。结果注射无水乙醇后,随着时间进展,X线片显示椎间隙高度显著下降、椎间隙变窄、边缘骨赘增生,MRI T2WI显示椎间盘低信号;苏木精-伊红染色(HE)显示终板的生长板厚度变薄,终板结构破损,同时软骨终板细胞退化、直至消失,髓核中细胞发生转化(由空泡细胞转变为软骨样细胞,进而形成纤维软骨样细胞)造成髓核纤维化,纤维环结构排列紊乱、纤维化程度逐步加重;免疫组织化学染色显示,发生退行性变的终板组织内有ET-1表达,但随着退行性变加剧,ET-1表达强度下降;提取的退行性变软骨终板细胞(造模后1个月)也显示细胞质内ET-1强表达。结论通过注射无水乙醇阻碍椎体-终板营养途径可成功建立兔椎间盘退行性变模型,终板退行性变过程中伴随ET-1的表达。     

经后路微创治疗伴终板Modic改变腰椎间盘突出症的疗效分析

目的:探讨经后路内窥镜下微创治疗伴腰椎终板信号改变(Modic改变)腰椎间盘突出症患者的手术疗效。方法:回顾性分析自2005年5月~2009年12月我院采用经后路内窥镜下髓核摘除术(MED)治疗单节段腰椎间盘突出症患者78例,男43例、女35例,平均年龄44.3岁(23~67岁),平均随访36.7个月(7~62个月),根据有无终板改变分为A、B两组。A组:MRI影像显示终板无信号改变,共33例;B组:MRI影像示终板有信号改变,共45例,其中ModlcⅠ、Ⅱ、Ⅲ型分别为13、25、7例。分别记录术前、术后及最终随访时的VAS、ODI值,并进行统计学分析。结果:术前A、B组的VAS、ODI值差异均无统计学意义(P>0.05)。术后ODI值改善率分别为A组86.2%、B组81.3%,VAS改善率分别为A组89.2%、B组77.2%,A组ODI值及VAS改善率与B组比较差异有显著性(P<0.05),B组终板不同Modic改变类型间疗效:术前、术后及末次随访间差异无显著性(P>0.05)。结论:后路内窥镜下髓核摘除术(MED)是治疗腰椎间盘突出症的一种有效术式,终板Modic改变可能是引起术后腰痛的一个原因,并影响术后腰痛的缓解,且MED术对治疗不同类型Modic改变腰椎间盘突出症的临床疗效无差异。     

CT引导下经皮纤维环穿刺建立兔腰椎间盘退变模型

【摘要】 目的：在CT引导下经皮纤维环穿刺建立兔腰椎间盘退变模型,并通过影像学和病理学验证其退变过程及效果。方法：3月龄新西兰大白兔18只,体重2.7~3.3kg,雌雄不限,术前均行X线及MRI检查。每只兔在螺旋CT引导下,用18G穿刺针经侧方皮下穿刺兔L5/6椎间盘（穿刺组）,确认刺入椎间盘纤维环深度约为5mm,并对L4/5椎间盘进行假性穿刺（穿刺达椎间盘边缘,但不刺入纤维环内;假穿刺组）,L3/4椎间盘作为对照椎间盘（对照组）。术后4周、8周、12周随机选取6只兔行X线片及MRI检查,观察各组椎间隙高度、邻近骨质改变及椎间盘信号改变,以“术后椎间隙高度/术前椎间隙高度×100”计算椎间盘高度相对值(DHRV),并进行椎间盘改良Thompson分级法分级;X线片及MRI检查结束24h内处死动物,选取对照、假穿刺和穿刺组椎间盘进行组织形态学及免疫组织化学分析。结果：对照组及假穿刺组术后4、8、12周,X线片示椎间隙高度无降低,无终板骨质硬化与骨赘形成;MRI T2加权成像图像示各椎间盘均呈高信号;组织学检查见髓核细胞数量较多,分布均匀,纤维环排列呈同心圆层状;免疫组化分析髓核呈Ⅰ型胶原染色强阳性,Ⅱ型胶原染色阴性,在各时间点表现无明显差别。穿刺组椎间盘在术后4周X线片即可见椎间隙高度轻度降低（DHRV=70.78±4.55）,MRI示椎间盘信号强度轻度下降,组织学上见纤维环结构紊乱、髓核细胞轻度减少;术后8周椎间隙高度明显降低（DHRV=50.63±4.04）,开始出现终板骨质硬化,MRI示椎间盘信号强度明显下降,组织学上髓核被胶原组织分裂为含较多椭圆形细胞的细胞岛,出现纤维软骨细胞,纤维环层状结构变形、部分断裂;术后12周椎间隙高度继续下降（DHRV=44.78±2.61）,骨赘形成、终板骨质硬化明显,MRI示椎间盘信号强度继续减弱,组织学上见髓核被纤维软骨组织所代替,纤维环层状组织碎裂、解体;免疫组织化学分析示术后4、8、12周髓核Ⅰ型胶原染色逐渐增强,Ⅱ型胶原染色逐渐减弱。各时间点对照组椎间盘的DHRV及改良Thompson分级与假穿刺组比较均无统计学差异（P＞0.05）;穿刺组在术后不同时间点的DHRV降低、改良Thompson分级增高与对照组及假穿刺组比较均有统计学差异（P<0.05）;随着穿刺时间的延长,穿刺组DHRV呈进行性降低趋势,改良Thompson分级进行性升高,两者在术后4、8、12周间均有统计学差异（P<0.05）。结论：CT引导下经皮纤维环穿刺法诱导兔椎间盘退变模型构建成功,操作方法简单、创伤小,经影像学及病理学证实其退变过程为渐进性。     

雌激素受体在椎间盘组织中的表达及意义

【摘要】 目的：通过观察雌激素α、β受体在正常与退变的人椎间盘组织的表达,探讨雌激素受体（ER）与椎间盘退变的关系。方法：根据改良Pfirrmann分级将收集的椎间盘组织分为三组：对照组,外伤导致腰椎爆裂性骨折手术取出的正常髓核组织（Pfirrmann分级1~2级）;观察组,女性腰椎滑脱及腰椎间盘突出症手术取出的退变髓核组织,Pfirrmann分级3～4级为A组,5级为B组。用HE染色法观察对照组和A、B组各15例人腰椎椎间盘髓核组织及髓核细胞的形态学变化;用免疫组织化学染色法（Elivison二步法）检测对照组和A、B组髓核组织中ER-α、ER-β的表达;采用Western-blot法检测对照组和观察组髓核组织中ER-α、ER-β的表达。结果：HE染色示对照组髓核组织中髓核细胞分布均匀,形态完整,未见明显细胞凋亡现象,细胞外基质染色鲜亮,分布均匀;A、B两组髓核细胞分布不均匀,形态不规则,凋亡现象明显,细胞核增大,染色深,细胞外基质减少,色彩灰暗,B组较A组更为明显。免疫组织化学染色示ER-α、ER-β在对照组的髓核组织见有明显棕黄色颗粒,在A、B两组表达减少,以ER-β减少最显著,经统计学分析,A、B两组与对照组间ER-β的表达有显著性差异（P＜0.01）,ER-α的表达较对照组无统计学差异（P＞0.05）,其中A组和B组间无明显差异（P＞0.05）。Western-blot方法检测,ER-α表达A组（0.876±0.058）、B组（0.757±0.045）较对照组（0.885±0.036）降低,但无统计学差异（P>0.05）;ER-β表达A组（0.947±0.043）、B组（0.626±0.042）较对照组（1.275±0.150）显著降低（P＜0.01）,B组较A组表达明显减少（P＜0.01）。结论：在人的髓核组织中的髓核细胞（类软骨细胞）的胞核和胞浆中均存在ER。ER-α、ER-β在退变的椎间盘组织都明显减少,以ER-β最为明显,提示雌激素可能通过ER-β的介导对髓核细胞功能起调控作用。     

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.