胎儿毛乳头细胞的培养和鉴定及其体外诱导分化

目的探讨胎儿毛乳头细胞（dermal papilla cells，DPCs）生物学特性和体外诱导分化潜能，论证作为组织工程种子细胞的可行性。方法Ⅰ型胶原酶消化法分离毛乳头，Eagle动物细胞培养基（DMEM）／F12（3：1）中培养细胞，通过免疫荧光检测α平滑肌动蛋白（smooth muscle actin-α，SMA—α）、Ⅰ型胶原、Ⅱ型胶原、层粘连蛋白，对细胞的生物学特性进行鉴定。取第3、7代细胞以成脂诱导液、成骨诱导液体外定向诱导7～10d，油红染色和Von Kossa染色、骨桥蛋白免疫荧光检测鉴定细胞的成脂和成骨特性。结果体外培养的DPCs表达SMA—α、Ⅰ型胶原、Ⅳ型胶原和层粘连蛋白，成脂诱导10d后油红染色可见细胞胞浆内红色脂滴形成，成骨诱导7d后Von Kossa染色细胞间有黑色钙结节形成，细胞表达骨桥蛋白。结论体外培养DPCs具有干细胞特性，可作为皮肤组织工程和骨组织工程一种新的种子细胞。     

人羊水来源间充质干细胞冻存后生物学特征研究

目的体外分离培养人羊水间充质干细胞(human amniotic fluid-derived mesenchymal stem cells,HAFMSCs),观察低温冻存复苏后HAFMSCs生物学特征,为进一步研究奠定理论基础。方法取12份自愿捐赠的孕16～20周羊水标本,采用改良两步法分离培养HAFMSCs,用含量不同的FBS、DMSO冻存液冻存细胞,液氮冻存12周后42℃水浴复苏,锥虫蓝染色检测细胞存活率,MTT法检测细胞增殖速度并绘制生长曲线,流式细胞仪检测冻存复苏后HAFMSCs表型。对冻存复苏后的HAFMSCs进行成脂、成骨诱导分化培养,并分别采用油红O、von Kossa染色进行鉴定;实时荧光定量PCR分析细胞冻存前后Oct-4、Nanog mRNA表达差异。结果细胞冻存12周后,不同的冻存方案对细胞存活率影响有差异,优化的冻存方案为DMEM/FBS/DMSO=50%/40%/10%。冻存复苏后的HAFMSCs呈漩涡状排列,生长曲线呈S形,与冻存前细胞生长曲线相似。流式细胞仪检测示冻存复苏后细胞的MSCs表型CD29、CD44、CD73、CD90为阳性,造血干细胞表型CD34、CD45为阴性。成脂、成骨诱导21 d,油红O、von Kossa染色均呈阳性。实时荧光定量PCR检测示冻存前后Oct-4、Nanog mRNA表达水平差异无统计学意义(P>0.05)。结论 HAFMSCs具有体外增殖快、分化能力强的优势;并可耐受短期冻存,复苏后细胞存活率高,生物学特征及分化潜能未发生明显变化,冻存液DMEM/FBS/DMSO=50%/40%/10%是较好冻存方案。     

犬骨髓间充质干细胞体外分离、诱导成纤维细胞的实验研究

目的探讨体外稳定诱导骨髓间充质干细胞(BMSC)分化为成肌纤维细胞和成纤维细胞的方法,为构建组织工程瓣膜提供种子细胞。方法应用Percoll(密度1·073g/ml)淋巴细胞分离液分离健康犬骨髓标本,取分离的BMSC,在低糖改良Eagles培养液中培养,并用免疫组织化学的方法做细胞表型鉴定,然后用条件培养基对第2、3代细胞进行诱导分化,并用层黏连蛋白单抗对诱导后的细胞做免疫组织化学鉴定。并对诱导后细胞进行冻存,7d后复苏观察细胞的生长、增殖及功能。结果经Percoll液分离的骨髓单核细胞,经贴壁培养后,其表型为波形蛋白阳性、α平滑肌肌动蛋白阳性、CD3-4、层黏连蛋白阴性;诱导后细胞表达层黏连蛋白,阳性细胞数可达(50±3)%;诱导后BMSC经冻存复苏后,细胞复苏率(85±3)%,复苏后细胞生长、增殖旺盛,功能不受影响。结论BMSC体外能定向诱导分化为成肌纤维细胞和成纤维细胞,并符合种子细胞的要求。     

人脐血间充质干细胞的分离培养及其多向分化潜能的实验研究

目的 研究人脐血间充质干细胞(MSCs)分离培养的生物学特性及其向成骨、成脂诱导分化的能力.方法 从人脐血中分离扩增MSCs,显微镜下观察其形态及生长情况,绘制生长曲线,电镜下观察超微结构,流式细胞仪检测细胞表面标志物;成骨、成脂诱导后以碱性磷酸酶(ALP)染色、茜素红染色鉴定MSCs成骨分化潜能,油红O染色鉴定成脂分化潜能.结果 人脐血MSCs为成纤维细胞样,漩涡状贴壁生长排列,传至第110代细胞形态无明显变化;电镜下显示为低分化细胞;细胞表面不表达CD34和CD45,强表达CD29、CD44和CD90;成骨诱导后可检测到ALP表达及钙化结节形成;成脂诱导后可检测到脂滴形成.结论 人脐血中可分离出MSCs,与其他来源的MSCs具有类似的生物学特性及多向分化潜能,脐血有可能成为骨组织工程种子细胞的来源.     

TGF-β_1联合VEGF对人羊膜间充质干细胞向韧带成纤维细胞体外分化作用的研究

目的探讨人羊膜间充质干细胞(human amniotic mesenchymal stem cells,h AMSCs)是否具有MSCs特性,以及经TGF-β_1和VEGF联合诱导后是否具有向韧带成纤维细胞分化的能力。方法取自愿捐赠的足月产妇胎盘,采用胰蛋白酶胶原酶联合消化法分离培养h AMSCs,流式细胞术检测h AMSCs表型分子,免疫荧光染色检测h AMSCs其角蛋白-19(cytokeratin-19,CK-19)和波形蛋白表达情况。取第3代h AMSCs,分别使用含TGF-β_1和VEGF的L-DMEM/F12成韧带或纤维细胞诱导培养基(实验组)和普通L-DMEM/F12培养基(对照组)培养,细胞增殖-毒性检测试剂盒(cell counting kit-8,CCK-8)检测两组细胞增殖能力;培养5、10、15 d分别采用免疫荧光染色及实时荧光定量PCR检测韧带及血管生成相关特异性蛋白和基因表达。结果倒置相差显微镜观察示h AMSCs呈单层贴壁生长;流式细胞术结果示h AMSCs表达MSCs表型分子;免疫荧光染色示h AMSCs高表达波形蛋白、低表达CK-19;h AMSCs具有向成骨、成软骨及成脂细胞分化的能力。CCK-8法检测示,7 d时两组细胞均达增殖高峰,实验组细胞增殖能力于7 d后显著高于对照组(P0.05)。免疫荧光染色示,培养5、10、15 d时实验组Ⅰ型胶原、Ⅲ型胶原、纤维连接蛋白(Fibronectin)、细胞连接素(Tenascin-C)表达染色均较对照组增强。实时荧光定量PCR结果示,随时间延长实验组Ⅰ型胶原、Ⅲ型胶原、Fibronectin、α-肌动蛋白(α-smooth muscle actin,α-SMA)、VEGF m RNA相对表达量均逐渐上调(P0.05)。除培养5 d两组Ⅰ型胶原、Ⅲ型胶原、VEGF m RNA相对表达量比较差异无统计学意义(P0.05)外,其余各时间点实验组Ⅰ型胶原、Ⅲ型胶原、Fibronectin、α-SMA和VEGF m RNA相对表达量均显著高于对照组(P0.05)。结论 h AMSCs具有MSCs特征,且体外增殖能力良好,可作为组织工程种子细胞来源;体外诱导后韧带成纤维细胞及血管生成相关特异性基因表达上调,韧带成纤维细胞特异性蛋白分泌增加,TGF-β_1联合VEGF可作为构建组织工程韧带的生长因子选择。     

冻存对人脐血间充质干细胞生物学特性的影响

目的观察冻存复苏对人脐血（human umbili calcord blood）间充质干细胞（mesenchymal stem cells，MSCs）生物学特性的影响。方法体外分离、培养人脐血MSCs，传代后，将第3代的MSCs加入含10％二甲基亚砜（DMSO）和90％胎牛血清的细胞冻存液中，-196℃液氮保存4周，观察比较冻存前及冻存复苏后MSCs的形态、增殖及多向分化能力。结果冻存前及冻存复苏后，MSCs形态无明显差别，均呈典型的梭形，MSCs贴壁生长；MSCs生长曲线相似，冻存复苏后的细胞生长曲线略有下降，但差异无统计学意义（P〉0．05）；MSCs经脂肪诱导液诱导2周后，细胞浆中出现脂肪细胞所特有的脂肪滴，经0．5％油红0染色，脂肪滴染为红色，说明MSCs有向脂肪细胞分化的能力；Mscs经成骨诱导液诱导4周后，VonKossa染色可见黑色的矿化结节沉积，钙结节的形成为成骨细胞特有，说明Mscs有向成骨细胞分化的能力。提示冻存复苏后Mscs经诱导仍然可以向脂肪细胞和成骨细胞分化，与冻存前无明显差异。结论人脐血MSCs经冻存复苏后，其生物学特性可获良好保持。     

UVB诱导人皮肤成纤维细胞Ⅰ、Ⅲ型胶原下调机制的研究

目的 观察紫外线对原代人皮肤成纤维细胞Ⅰ、Ⅲ型胶原的影响并探讨其作用的分子机制.方法 使用组织块法分离培养原代人皮肤成纤维细胞,以不同剂量紫外线照射人皮肤成纤维细胞,倒置显微镜观察细胞形态学的改变;β-半乳糖苷酶(β-gal)细胞衰老试剂盒染色;western blot检测衰老标志物P16蛋白的表达;RT-PCR检测中波紫外线处理皮肤成纤维细胞不同时相Ⅰ、Ⅲ型胶原的改变及对MMP1、MMP3的影响.结果 20～40 mJ/cm2 UVB单次照射后可以成功诱导人皮肤成纤维细胞出现衰老形态学的改变,β-gal染色阳性率达到约90%,P16蛋白表达随时相明显升高;紫外处理成纤维细胞后,Ⅰ、Ⅲ型胶原表达水平明显降低;而MMP1、MMP3表达水平明显升高.结论 利用20～40 mJ/cm2中波紫外线照射可诱导人皮肤成纤维细胞衰老,不仅伴随Ⅰ、Ⅲ型胶原合成减少,而且通过升高MMP1、MMP3来降解已形成的Ⅰ、Ⅲ型胶原.以上数据表明,中波紫外线可以诱导人皮肤成纤维细胞衰老并在皮肤衰老过程中发挥重要作用,为了解及干预皮肤衰老过程提供了线索.     

骨形成蛋白2基因修饰的老年大鼠骨髓间充质干细胞成骨分化能力的研究

目的观察年龄因素对骨髓间充质干细胞(marrow mesenchymal stem cells, MSCs)成骨分化能力的影响;了解基因治疗对老年大鼠MSCs成骨分化能力的影响. 方法 1月龄(幼年组)、9月龄(成年组)及24月龄(老年组)雄性Wistar大鼠各6只,取MSCs经体外分离、培养及携带骨形成蛋白2(bone morphogenetic protein 2,BMP-2)基因的腺病毒载体(Ad-BMP-2)转染后,定量检测BMP-2、碱性磷酸酶(alkaline phosphate,ALP)表达,以及成骨细胞标志性蛋白:Ⅰ型胶原、骨涎蛋白(bone sialoprotein,BSP)和骨桥素(osteopontin, OPN)的表达.将转染的各组MSCs分别与磷酸三钙(tricalcium phosphate, TCP)复合后植入裸鼠体内,3周后取材,比较各组诱导异位成骨能力. 结果 ELISA检测表明BMP-2基因修饰的MSCs可以有效表达BMP-2,且表达量在各年龄组间差异无统计学意义(P>0.05);各组ALP于诱导后第9天达高峰,但组间差异均无统计学意义(P＞0.05);诱导后第7天,RT-PCR半定量检测示各组均有成骨细胞特征性蛋白,即:Ⅰ型胶原、OPN及BSP的明显表达,表达量在各组间差异无统计学意义(P>0.05);BMP-2基因转染的MSCs与TCP复合后可诱导裸鼠体内异位成骨,各组成骨量差异无统计学意义(P>0.05). 结论 BMP-2基因修饰的老年大鼠MSCs可以恢复成骨分化能力,基因治疗可能为老年性骨骼疾病提供一种新的治疗途径.     

RNA干扰沉默CTGF表达对人成骨样MG63细胞I型胶原、ALP mRNA表达的影响

目的本研究将利用RNA干扰技术,阻断CTGF在人成骨样MG63细胞中的表达,观察CTGF降表达后对人成骨样MG63细胞Ⅰ型胶原、碱性磷酸酶 mRNA表达的影响。方法针对人CTGF mRNA440、875、910位点设计、合成3对21核苷酸siRNA（siRNA1、siRNA2、siRNA3）;在阳离子脂质体介导下转染人成骨样MG63细胞,以空白及非特异性siRNA作为对照,转染48h后收集细胞。采用Northern杂交研究CTGF mRNA表达水平的改变,半定量RT-PCR观察Ⅰ型胶原、ALP mRNA表达的改变,Western blotting观察CTGF蛋白表达的变化。MTT法测定RNA干扰后人成骨样MG63细胞活力的改变。结果空白对照组相比,转染siRNA1、siRNA3的MG63细胞CTGF mRNA和蛋白表达明显下调,转染siRNA2及非特异性siRNA的MG63细胞CTGF的表达无明显变化。转染siRNA1、siRNA3的MG63细胞Ⅰ型胶原、ALP mRNA表达明显下调,细胞活力明显降低。结论针对人CTGF mRNA设计、合成的siRNA可有效抑制人成骨样MG63细胞CTGF的转录和表达;CTGF表达下调可抑制MG63细胞表型标志物Ⅰ型胶原、ALP mRNA的表达,降低MG63细胞活力,这说明CTGF可能在维持骨代谢平衡中具有重要的作用。     

酪氨酸磷酸化蛋白在伤口愈合原胶原基因表达中的作用

目的　研究伤口愈合时成纤维细胞与纤维粘连蛋白黏附 ,以及黏附诱导的酪氨酸磷酸化蛋白在成纤维细胞表达原胶原mRNA中的作用。方法　采用RT PCR、免疫印迹法分别检测伤口愈合时成纤维细胞原胶原mRNA表达的变化及黏附诱导的酪氨酸磷酸化蛋白 ,并观察阻断酪氨酸磷酸化后原胶原mRNA和酪氨酸磷酸化蛋白的变化。结果　伤口愈合时成纤维细胞与纤维粘连蛋白黏附 ,可诱导 98kd、6 5kd酪氨酸磷酸化蛋白生成 ,且原胶原proα1 (Ⅰ )mRNA的表达显著增加 ;经酪氨酸激酶抑制后 ,原胶原proα1 (Ⅰ )mRNA显著降低。结论　成纤维细胞与纤维粘连蛋白黏附 ,在伤口愈合原胶原表达增加中具重要作用 ,由黏附诱导的酪氨酸磷酸化是其中的一个重要环节。     

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.     

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.     

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.