大鼠脊髓损伤后内源性神经干细胞增殖过程中Wnt-1的表达

目的:探讨大鼠脊髓损伤后信号蛋白Wnt-1的表达及其与脊髓内源性神经干细胞(ENSCs)早期增殖的关系.方法:30只Wister成年大鼠,随机分为正常对照组(A组,n=5)和损伤组(B组,n＝25).A组不损伤脊髓,B组在大鼠T10采用经典Allen′s 打击法(25g·cm)造成脊髓损伤,于造模后1d、3d、1周、2周、4周进行取材,对距离损伤中心5mm的脊髓行免疫组化染色,检测ENSCs的增殖及Wnt-1蛋白表达的动态变化,与A组比较,并统计分析二者之间的相关性.结果:30只大鼠均进入结果分析.A组脊髓在中央管周围、外周软膜可见极少数BrdU/Nestin阳性细胞,白质中几乎没有.B组中BrdU/Nestin阳性细胞于损伤后24h表达于室管膜以及软膜,灰质和白质亦有少量表达,3d时明显增多,1周达到高峰(P<0.05),2周开始逐渐下降,4周时仍可见少量BrdU/Nestin阳性细胞.B组各时间点与A组比较差异有显著性意义(P<0.05).B组大鼠各时间点均有Wnt-1蛋白的表达,损伤后第1天开始表达,3d达到高峰,一直至脊髓损伤后2周Wnt-1都维持在较高的表达水平.Wnt-1蛋白的表达与Nestin的表达具有相关性(r=0.893,P<0.05).结论:大鼠脊髓损伤后信号蛋白Wnt-1表达增加,其可能与大鼠ENSCs的早期增殖有关.     

大鼠脊髓损伤后巢蛋白在脊髓组织中的表达

目的探讨大鼠脊髓损伤后巢蛋白(nestin)的表达规律及其意义。方法30只Wister成年大鼠,随机分为正常对照组(A组)、损伤组(B组)。采用Allen打击模型(25g·cm),在T10段造成急性脊髓损伤,于损伤后1d、3d、1周、4周、8周进行取材,对距离损伤中心5mm处脊髓进行nestin免疫组化检测。应用图像分析软件进行nestin阳性区域面积侧算。结果A组脊髓室管膜细胞只可见极少数细胞胞浆内nestin表达,白质中几乎无表达。B组中nestin于损伤后24h表达于室管膜以及软膜,灰质和白质亦有少量表达,1周达到高峰(P<0.05),4周明显下降,8周时很少或几乎无表达。结论脊髓组织的许多部位可能存在具有分化和更新潜能的祖细胞,脊髓损伤后这些细胞被激活,在功能恢复中可能发挥着重要的作用。     

半乳凝素-1对脊髓损伤大鼠室管膜区细胞增殖的影响

【摘要】 目的：观察成年大鼠脊髓损伤后半乳凝素-1对室管膜区细胞增殖的影响,为进一步研究脊髓损伤后内源性神经干细胞的自身修复作用提供理论依据。方法：72只健康雌性SD大鼠,1.5月龄,体重190~220g,分为假手术组（A组）、模型组（B组）和治疗干预组（C组）,每组24只。B、C两组均在T10节段制作急性脊髓损伤模型,A组仅行椎板切除。C组术后24h经枕大池蛛网膜下腔注入20μl（0.2g/L）半乳凝素-1,单次给药;其余两组仅给予等量的生理盐水。术后1d、7d每组进行后肢运动功能BBB评分,术后7d每组行免疫组织化学方法检测脊髓室管膜区BrdU和巢蛋白（Nestin）阳性细胞的表达变化情况。结果：术后1d后肢运动功能BBB评分A组为21.00±0.00分,B组为1.65±0.05分,C组为1.59±0.14分,B、C两组比较无显著性差异（P>0.05）。术后7d后肢运动功能BBB评分,C组（12.98±0.15）、B组（6.38±0.21）与A组（21.00±0.00）比较均有显著性差异（P<0.05）;C组与B组比较有显著性差异（P<0.05）。术后7d,A组脊髓室管膜区免疫组化BrdU和Nestin阳性细胞相对值分别为0.02±0.01和0.01±0.00,仅见极少量;B组分别为0.41±0.14和0.35±0.13,与A组比较均明显增加（P<0.05）;C组分别为1.02±0.25和0.88±0.20,均比B组增加更加明显（P<0.05）。术后7d,A组脊髓室管膜区免疫组化BrdU和Nestin积分光密度值分别为17.12±3.47和10.59±2.11,B组（32.43±4.96,24.95±7.43）和C组（45.11±6.01,36.99±5.29）均高于A组（P<0.05）,但C组高于B组（P<0.05）。结论：大鼠脊髓内室管膜区细胞具有潜在的增殖和分化能力,在损伤后该功能可被激活,半乳凝素-1对室管膜区细胞的增殖和分化具有明显促进作用。     

甲基强的松龙对大鼠急性脊髓损伤后Nogo-A表达的影响

目的：探讨大剂量甲基强的松龙（MP）对急性脊髓损伤（SCI）大鼠脊髓组织中Nogo-A蛋白表达的影响。方法：将56只成年SD大鼠分为正常对照组（A组,n=8）、急性脊髓损伤组（B组,n=24）和急性脊髓损伤后大剂量MP治疗组（C组,n=24）,C组在损伤后早期从尾静脉注射大剂量MP治疗。分别在术后3、7、14d对B、C组大鼠后肢运动功能行BBB评分,再在各时间点处死动物,取受损节段脊髓行HE染色及免疫组化染色观察形态学变化和Nogo-A在脊髓组织中的分布特点;同时应用Western-blot方法测定各组相应时间点Nogo-A表达量,并与A组比较。结果：B、C组大鼠在损伤后各个时间点后肢运动功能均有一定程度的恢复,Nogo-A蛋白在各组大鼠脊髓组织中均呈阳性表达,分布于神经细胞的细胞浆和脊髓神经纤维周围呈包裹神经纤维的状态。B、C组各个时间点Nogo-A表达均显著高于A组（P〈0.05）,7d时最高,14d时的表达量仍高于正常组;C组在各个时间点的表达量显著低于B组,差异有显著性（P〈0.05）。结论：大鼠急性脊髓损伤后Nogo-A显著升高,早期应用大剂量MP对Nogo-A的表达具有明显的抑制作用。     

显微操作在脐血干细胞移植修复大鼠脊髓损伤中的应用

[目的]建立大鼠脊髓全横断损伤模型,应用显微操作方法和人脐血干细胞移植修复大鼠脊髓损伤,观察显微操作技术对大鼠受损脊髓功能恢复的影响.[方法]取足月健康顺产新生儿脐血,分离、培养脐血干细胞.60只SD雌性大鼠,随机分为假手术对照组(A组,n=10)、实验对照组(B组,n=10)、常规治疗组(C组,n=20)和显微治疗组(D组,n=20).A组大鼠只打开椎板;B、C组大鼠采用常规方法行T 8-9,平面脊髓全横断,造成急性脊髓损伤,C组大鼠于脊髓两断端用1 μl注射器分别注射脐血干细胞悬液1μl(干细胞浓度为6×10 9/L～7×109/L),B组同法注射等量PBS液;D组采用显微操作技术行脊髓横断,并以口径50 μm的毛细玻璃针用相同方法注射脐血干细胞.术后1～8周内每周进行1次后肢BBB评分,术后第8周处死大鼠,对比观察术中和术后第8周各组大鼠脊髓大体标本外形、颜色、质地和体积大小改变.[结果]A组大鼠手术前后运动功能、脊髓大体标本未见明显变化.B、C、D组大鼠术后双侧后肢完全性瘫痪,B组大鼠无明显恢复.而C、D组大鼠,从术后第2周开始逐渐恢复部分后肢运动功能.第3周以后,D组大鼠后肢运动功能BBB评分明显优于C组,具有显著性差异(P＜0.05).术后第8周,所有大鼠脊髓横断处均瘢痕愈合,B组大鼠远侧段脊髓干瘪、皱缩;C组大鼠远侧段脊髓直径轻度变细,外形尚饱满;D组大鼠横断处两侧脊髓直径无明显差异,外形圆润,但局部可见明显瘢痕粘连.[结论]人脐血干细胞移植对脊髓横断性损伤具有较好的治疗作用,显微操作技术的应用能最大可能地减少人为造成的脊髓损伤,有利于脊髓损伤的功能修复.     

骨髓间质干细胞与胚胎嗅鞘细胞联合移植治疗大鼠脊髓损伤的实验研究

目的：观察人骨髓间质干细胞（MSCs）与胚胎嗅鞘细胞（OECs）联合移植治疗大鼠脊髓损伤的效果，探讨共移植的OECs对MSCs分化的影响。方法：采用Allen’s法制作大鼠脊髓损伤模型．随机分为MSCs移植组（A组）、OECs移植组（B组）、MSCs与OECs联合移植组（C组）及PBS注射组（D组），术后1-5周采用BBB评分、经颅磁刺激运动诱发电位及组织学方法检查脊髓损伤修复情况。结果：术后2周起，A、B、C组BBB评分和诱发电位潜伏期与D组比较恢复明显，C组与A、B组相比亦有显著性差异（P〈0．05），术后5周时C组损伤区有较密的神经轴突分布，近端可见大量成束再生轴突；A、B组损伤区及近端再生轴突分布稀疏；D组损伤区及近端少见轴突。C组移植的MSCs中Nestin及NF表达阳性的比率较A组高（P〈0.05）。结论：联合移植OECs可促进MSCs向神经元方向转化，提高MSCs分化为神经元的比例；MSCs与OECs可以在脊髓损伤修复中发挥协同作用，联合细胞移植是提高脊髓损伤修复效果的可行方法。     

脊髓损伤后Wnt-3a表达对神经干细胞增殖的影响

目的 研究大鼠脊髓损伤后Wnt-3a信号蛋白表达及其对脊髓神经干细胞增殖的影响.方法 选用30只SD成年雌性大鼠,随机分为A组(正常对照组,n=5)和B组(脊髓损伤组,n=25).A组不损伤脊髓,B组在大鼠L9-10节段采用Allen打击法造成脊髓损伤,于造模后1、3、7、14、28 d取材.对距离损伤中心5mm脊髓行...     

硫酸软骨素酶ABC对大鼠急性脊髓损伤后神经中丝和胶质纤维酸性蛋白的影响

目的：探讨硫酸软骨素酶ABC（ChABC）对大鼠急性脊髓损伤后神经中丝200（NF200）和胶质纤维酸性蛋白（GFAP）的影响.方法：SD大鼠72只,雌雄不限,随机分为假手术组（A组）、损伤对照组（B组）和ChABC治疗组（C组）,每组24只.A组仅打开椎板及置管,不损伤脊髓,不给药;C组和B组均采用Allen＇s法制作大鼠T10脊髓损伤模型,分别在伤后即刻和随后每天1次连续1周蛛网膜下腔注射ChABC（6μl/次）和等量生理盐水.术后1d、1周、2周和4周每组各处死6只大鼠,B组和C组以损伤区为中心、A组在相应部位切取1cm长的脊髓组织,以HE染色观察脊髓组织形态变化,应用免疫组化方法检测脊髓组织中NF200和GFAP的变化.结果：HE染色示A组脊髓无胶质细胞增生和胶质瘢痕形成;B、C组脊髓损伤区有胶质细胞增生和胶质瘢痕,C组明显少于B组.A组术后1d、1周、2周和4周时NF200阳性细胞数及灰度值和GFAP染色阳性面积无差异,1、2、4周时B、C组脊髓损伤区NF200染色阳性细胞数及灰度值和GFAP染色阳性面积均较A组显著增加（P＜0.05或P＜0.01）,1d和1周时C组NF200染色阳性细胞数及灰度值与B组比较无显著性差异,2周和4周时C组明显高于B组（P＜0.05）;1d、1周和4周时C组GFAP染色阳性面积与B组无显著性差异,2周时C组显著小于B组（P＜0.05）.结论：ChABC能提高大鼠急性脊髓损伤后神经细胞内NF200的表达并抑制GFAP的表达,进而促进神经细胞的修复,抑制胶质细胞的增生和胶质瘢痕的形成,对脊髓损伤具有保护作用.     

坐骨神经预损伤后背根神经节中miRNomes改变对大鼠脊髓后索损伤修复的影响

【摘要】 目的：研究大鼠坐骨神经预损伤后背根神经节中miRNomes改变对脊髓后索损伤修复的影响。方法：39只雌性Wistar大鼠随机分为A、B、C、D组。A组（n=12）坐骨神经损伤造模后7d进行T10节段脊髓后索损伤造模,B组（n=12）仅进行T10节段脊髓后索损伤造模,C组（n=12）仅进行坐骨神经损伤造模,D组（n=3）不进行任何造模操作。A组和B组分别于脊髓后索损伤造模后4h、3d、7d、14d取背根神经节行总RNA提取和Western blot检测,于脊髓后索损伤造模后14d取损伤中心脊髓组织行神经丝蛋白200（NF-200）免疫组织化学染色和HE染色;C组于A组各时间点取材的同时取背根神经节行总RNA提取和Western blot检测;D组取背根神经节行总RNA提取和Western blot检测。对A、B两组各时间点背根神经节miRNA表达谱进行微阵列芯片分析和生物信息学分析,观察与坐骨神经预损伤促进脊髓后索损伤修复有关的miRNA,选出A组中与B组相比变化倍数明显、经过生物信息学分析靶蛋白为Dusp4的miR-199a-5p进行研究。并用RT-qPCR技术对各组miR-199a-5p及A、B和D组Dusp4 mRNA表达进行检测,用Western blot技术检测各组Dusp4蛋白以及A、D组p38蛋白和p-p38蛋白,对A组和B组脊髓后索损伤中心脊髓组织用NF-200免疫组织化学染色及HE染色观察损伤脊髓的恢复情况。结果：芯片分析结果显示miR-199a-5p在A组各个时间点表达与D组相比明显下调,B组miR-199a-5p在脊髓后索损伤后4h表达与D组相比上调,3d、7d和14d的表达量无明显变化。RT-qPCR结果显示A组各时间点miR-199a-5p表达与D组相比下调（P＜0.05）,B组miR-199a-5p在脊髓后索损伤后4h表达与D组相比上调（P＜0.05）,3d、7d和14d的表达量与D组比较无明显变化,C组各时间点miR-199a-5p表达与D组比较无明显变化。A组和B组各时间点Dusp4 mRNA表达与D组相比无明显变化。A组Dusp4蛋白在脊髓后索损伤后各个时间点与D组比较均有上调且存在统计学差异（P＜0.05）。B组Dusp4蛋白在脊髓后索损伤后4h表达与D组相比显著下调（P＜0.05）,脊髓后索损伤后3d、7d、14d与D组比较无明显差异。C组Dusp4蛋白在各时间点的表达水平与D组比较无明显差异。A组p38蛋白及p-p38蛋白的表达变化趋势与miR-199a-5p趋势一致。在脊髓后索损伤后14d,与B组比较A组损伤中心尾端脊髓NF-200表达明显增加,且损伤中心尾端脊髓白质纤维束形态规整、后索纤维束排列有序。结论：大鼠坐骨神经预损伤后背根神经节中miR-199a-5p表达下调可以促进脊髓后索损伤的修复。     

预变性周围神经移植和神经生长因子灌注对脊髓损伤后上行传导束再生的影响

目的：评价应用预变性周围神经移植（PPNG）和神经生长因子（NGF）灌注对大鼠脊髓损伤（SCI）后上行传导束再生的影响及两者协同效果.方法：50只SD大鼠分5组,每组10只,A组为PPNG和NGF灌注组;B组为PPNG组;C组为NGF灌注组;D组为单纯损伤组;E组为正常对照组.A、B组于脊髓损伤前1周取坐骨神经约3mm并置于DMEM中.1周后造成T10脊髓后索损伤并将预变性的外周神经植入,A、C组脊髓损伤后置管注射NGF,每日2μg,共2周;D组单纯损伤脊髓,E组不损伤脊髓.8周后行辣根过氧化物酶（HRP）示踪法计数再生的纤维,按照脊髓与移植物的关系分为脊髓尾端、尾端过渡区、移植物尾端、移植物头端、头端过渡区、脊髓头端六个区,简称Ⅰ、Ⅱ、Ⅲ、Ⅳ、Ⅴ、Ⅵ区.结果：在Ⅲ、Ⅳ、Ⅴ区,A组标示的纤维数量显著高于B、C组（P＜0.05）,Ⅵ区均无示踪纤维;D组几无纤维通过移植物.结论：联合应用PPNG及NGF灌注可明显促进大鼠SCI后上行传导束的再生,使再生的纤维跨过两道瘢痕,重新长入脊髓白质内.     

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 Teaspoon Pump for Pumping Blood with High Hydraulic Efficiency and Low Hemolysis Potential

Abstract: Virtually all blood pumps contain some kind of rubbing, sliding, closely moving machinery surfaces that are exposed to the blood being pumped. These valves, internal bearings, magnetic bearing position sensors, and shaft seals cause most of the problems with blood pumps. The original teaspoon pump design prevented the rubbing, sliding machinery surfaces from contacting the blood. However, the hydraulic efficiency was low because the blood was able to "slip around" the rotating impeller so that the blood itself never rotated fast enough to develop adequate pressure. An improved teaspoon blood pump has been designed and tested and has shown acceptable hydraulic performance and low hemolysis potential. The new pump uses a nonrotating "swinging" hose as the pump impeller. The fluid enters the pump through the center of the swinging hose; therefore, there can be no fluid slip between the revolving blood and the revolving impeller. The new pump uses an impeller that is comparable to a flexible garden hose. If the free end of the hose were swung around in a circle like half of a jump rope, the fluid inside the hose would rotate and develop pressure even though the hose impeller itself did not "rotate"; therefore, no rotating shaft seal or internal bearings are required.     

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.     

Tissue perfusion in relation to cardiac output during continuous positive-pressure ventilation and administration of propranolol or verapamil

Background : Our objective was to determine whether administration of propranolol or verapamil modifies the hemodynamic adaptation to continuous positive-pressure ventilation (CPPV), in particular the regional distribution of cardiac output (CO).
Methods : General hemodynamics and regional blood flows assessed by microsphere technique (15 (μm) were recorded in 16 anesthetized pigs during spontaneous breathing (SB) and CPPV with 8 cm H₂O end-expiratory pressure (CPPV8) before and after intravenous administration of propranolol (0.3 mg · kg⁻¹ followed by 0.15 mg · kg⁻¹ · h⁻¹, n=8) or verapamil (0.1 mg · kg⁻¹ followed by 0.3 mg · kg⁻¹ · h⁻¹, n=8).
Results : CPPV8 depressed CO by 25% without shifts in its relative distribution with the exception of a noteworthy increase in adrenal perfusion. Propranolol increased arterial blood pressure, and due to a fall in heart rate, CO dropped by 25%. The kidneys and, to a lesser extent, the splanchic region and central nervous system received increased fractions of the remaining CO at the expense of skeletal muscle flow. Similar patterns were seen during SB and CPPV8 such that the combination of propranolol and CPPV8 depressed CO by 50%. The circulatory effects of verapamil were less evident but myocardial perfusion tended to increase.
Conclusions : The combination of propranolol or verapamil with CPPV does not result in any specific hemodynamic interaction in anesthetized pigs, except that the combined effect of propranolol and CPPV may severely reduce CO.     

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.     

Volatile anaesthetics reduce adhesion of blood platelets under low-flow conditions in the coronary system of isolated guinea pig hearts

Background : Inhibitory effects of volatile anaesthetics on platelet aggregation have been demonstrated in several studies. However, the influence of volatile anaesthetics on intracoronary platelet adhesion has not been elucidated so far.
Methods : Isolated hearts of guinea pigs were perfused with buffer in the absence or presence of volatile anaesthetics (0.5 and 1 MAC) at constant coronary flow rates of 5 ml/min for 25 min, then 1 ml/min for 30 min and again 5 ml/min for 10 min. Before, during and after low-flow perfusion, a bolus of human platelets was applied into the coronary system. To simulate thrombogenic conditions, 0.3 U/ml human thrombin was infused during low-flow perfusion and reperfusion. The number of platelets sequestered to the endothelium was calculated from the difference between coronary in- and output of platelets. The myocardial production of lactate and consumption of pyruvate and coronary perfusion pressure were also determined.
Results : At a flow rate of 5 ml/min only about 3% of the applied platelets did not emerge from the coronary system, in any group. In contrast, 13.1±1.2% (mean±SEM) of infused platelets became adherent in low-flow perfusion in the control group without anaesthetic. The adherence was reduced with each 1 MAC isoflurane (to 6.2±1.2%), sevoflurane (to 4.4±0.9%) or halothane (to 3.2±1.5%) (each P <0.05 vs. control). Volatile anaesthetic, 0.5 MAC, did not inhibit platelet adhesion to a statistically significant extent in any case. Perfusion pressure and metabolic parameters were not statistically different between the control and the hearts exposed to anaesthetics.
Conclusion : Volatile anaesthetics in a concentration of 1 MAC can reduce the adhesion of platelets in the coronary system under reduced flow conditions. This action does not arise from vasodilation or inhibition of ischaemic stress.     

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.     

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.     

Systemic analgesia adapted to the children's condition

A concept of balanced analgesia using nonsteroidal anti-inflammatory drugs (NSAIDs), paracetamol (acetaminophen), opioids, and corticosteroids can also be used in patients with pre-existing illnesses. NSAIDs are the most effective treatment for acute pain of moderate intensity in children; however, these drugs should be avoided in patients at increased risk for serious side effects, e.g. patients with renal impairment, bleeding tendency, or extreme prematurity. NSAIDs can be given with minimal risks to the younger child with mild to moderate asthma, and, in these patients, the use of steroids can be encouraged; in addition to their antiemetic and analgesic action, a beneficial effect on asthma symptoms can be expected. In the non-intubated child with cerebral trauma, exaggerated sedation caused by opioids and increased bleeding tendency caused by NSAIDs must be avoided. In neonates and small infants, the oral administration of sucrose or glucose is helpful to minimize pain reaction during short uncomfortable interventions.