miR-124-3p经Wnt通路因子Axin1调控骨髓间充质干细胞的研究

目的 探讨miR-124-3p经Wnt通路因子A(Axin1)对骨髓间充质干细胞（BMSCs）的分子靶向机制及调节BMSCs的成骨分化进而参与绝经后骨质疏松（PMOP）的形成。方法 收集20例股骨骨折需要手术并扩髓或暴露髓腔的患者,10例绝经后骨质疏松妇女（PMOP组）和10例非骨质疏松的绝经后妇女（对照组）,术中取骨髓组织3~5 mL,建立体外BMSCs细胞模型,用流式细胞仪检测BMSCs标志物,将BMSCs诱导分化为成骨细胞,RT-qPCR法检测miR-124-3p的表达。双荧光素酶报告基因系统检测miR-124-3p结合位点A-Axin1。构建miR-124-3p过表达载体,miR-124-3p过表达转染PMOP-BMSCs同时更换成骨诱导培养基进行成骨诱导培养。诱导第7、14、21 天 分别收集细胞进行检测碱性磷酸酯酶染色（ALP）和茜素红染色。成骨诱导第7天,RT-qPCR检测各组BMSCs中Runx2、Osterix靶因子Axin1的表达。Western Blotting检测miR-124-3p转染BMSCs后的表达与Axin1关系。结果 ①RT-qPCR法检测miR-124-3p的表达,PMOP组低于对照组。②miR-124-3p过表达转染、成骨诱导,随着诱导时间的延长,细胞培养液中ALP水平逐渐上升,茜素红染色可见结节沉积逐增加。③RT-qPCR检测成骨诱导第7天,Runx2和Osterix的表达,BMSC+成骨分化液组明显高于BMSC组,BMSC+过表达miR-124-3p组较其对照组明显上升;Axin1的表达,BMSC+成骨分化液组明显低于BMSC组,BMSC+过表达miR-124-3p组较其对照组显降低。④荧光素酶报告基因实验证明了miR-124-3p与Axin1的可结合性。⑤Western Blotting检测BMSCs,miR-124-3p过表达组Axin1表达显著下降,而miR-124-3p抑制组Axin1表达显著升高。结论 miR-124-3p可通过Wnt通路靶点Axin1调节BMSCs的成骨分化进而参与PMOP的形成。     

miR-124-3p靶向Axin1 调控糖尿病骨质疏松成骨的研究

目的 研究miR-124-3p靶向Axin1 调控糖尿病骨质疏松症大鼠骨髓间充质干细胞（bone marrow mesenchymal stem cells ，BMSCs）成骨分化的作用。方法 20只糖尿病大鼠模型-SPF级SD雌性大鼠分为分组对照组10例、实验组10例，经过药物注射，测血生化指标，测骨密度。BMSCs培养，流式细胞学鉴定。检测对照组和实验组miR-124-3p mRNA的表达。过表达miR-124-3p（模拟物）7、14、21 d，检测ALP、茜素红染色成骨能力。第7天检测miR-124-3p mRNA表达水平。实验组细胞用miR-124-3p模拟物转染，分为高糖组和低糖组，检测中Axin1 mRNA水平。构建载体，与模拟物共转染，荧光素酶报告基因检测miR-124-3p和Axin1靶向结合。将实验组BMSCs分为高糖组和低糖组，检测实验组BMSCs高糖组及低糖组miR-124-3p、Runx2 mRNA的表达及茜素红染色和ALP染色结果。检测实验组模拟物在高糖组及低糖组miR-124-3p、Runx2 mRNA的表达及茜素红染色和ALP染色结果。结果 ELISA检测血生化指标，实验组TG、TC、FPG、HbA1C值上调，β-CTX和SOST上调，OC和骨密度下调。BMSCs培养，流式细胞学鉴定显示CD73和CD105的表达为阳性， CD34 和 CD45 的表达呈阴性。符合间充质干细胞的抗原特点，证实为BMSCs。实验组miR-124-3p表达明显低于对照组。过表达miR-124-3p（模拟物）7、14、21 d，ALP、茜素红染色随时间逐渐升高。第7天miR-124-3p表达水平显著升高。实验组细胞用miR-124-3p模拟物转染，结果高糖组Axin1 mRNA表达水平上调，但用miR-124-3p模拟物转染时水平下降。荧光素酶报告基因检测miR-124-3p和Axin1可以靶向结合。RT-qPCR检测实验组BMSCs高糖摄入显著降低了miR-124-3p、Runx2表达；高糖可抑制成骨分化，减少钙沉积，减少ALP表达。高血糖条件下miR-124-3p过表达（模拟物）中Runx2的表达显示，高糖+对照明显低于低糖+对照组；高糖+miR-124-3p模拟物明显高于高糖+对照组。茜素红染色和ALP染色显示，高糖+对照明显低于低糖+对照组；高糖+miR-124-3p模拟物明显高于高糖+对照组。结论 miR-124-3p能通过靶向抑制Axin1促进糖尿病骨质疏松症大鼠BMSC的成骨发生。     

壮筋养血汤介导MAPK/P38-ERK通路调控成骨成脂分化的作用机制

目的 探讨壮筋养血汤（Zhuangjin Yangxue Decoction,ZJYXD）通过LncRNA ANRIL介导的MAPK/ P38-ERK 通路调控成骨成脂分化的作用机制。方法 提取骨髓间充质干细胞（BMSCs）,并采用ANRIL慢病毒转染BMSCs;制备ZJYXD含药血清用于培养转染后的BMSCs。通过CCK-8检测BMSCs增殖活力;运用碱性磷酸酶、茜素红及油红O染色检测各组细胞成骨成脂分化情况;通过qRT-PCR、Western Blot法检测成骨、成脂、MAPK/ P38-ERK信号通路相关基因及蛋白的表达。选取24只SPF级C57BL/6雄性小鼠用于制作股骨横断骨折模型,造模后给予不同转染的BMSCs治疗并给予ZJYXD。通过X-ray与Micro-CT检测对照组、对照组+ZJYXD组、ANRIL过表达组、ANRIL过表达+ZJYXD组小鼠骨愈合情况。结果 与0 %含药血清相比,6 % ZJYXD含药血清对BMSCs细胞增殖能力最强（P<0.01）。ZJYXD干预后成骨染色加深,成骨相关基因OPN、RUNX2 mRNA及蛋白表达显著升高（P<0.01）;成脂染色减弱,相关基因PPARγ、C/EBPα mRNA及蛋白表达显著降低（P<0.01）。同时ZJYXD促进了P-ERK、P38蛋白表达（P<0.01）。X-ray及Micro-CT显示ZJYXD促进了小鼠骨折后愈合。当ANRIL过表达后,ZJYXD调节成骨成脂细胞分化作用消失,无法有效的促进骨折愈合。结论 壮筋养血汤具有促进成骨分化、抑制成脂分化的作用,而这种作用通过LncRNA ANRIL调控MAPK/ P38-ERK信号通路实现。     

实时荧光定量聚合酶链反应筛选重组人骨形态发生蛋白-2诱导比格犬骨髓基质干细胞成骨分化差异表达的miRNAs

目的 利用实时荧光定量聚合酶链反应(Q-PCR)方法筛选骨形态发生蛋白-2(rhBMP-2)诱导比格犬骨髓基质干细胞(BMSCs)成骨分化的miRNAs,探讨过表达miRNAs对成骨分化的影响.方法 选取4只比格犬分离BMSCs原代,取培养至第3代BMSCs分为2组:对照组(用基础培养基培养)和实验组(在基础培养基中加入rhBMP-2培养7d,诱导细胞成骨分化).采用碱性磷酸酶染色法验证细胞成骨分化情况,采用Q-PCR法筛选成骨分化细胞与对照组细胞差异表达的miRNAs;随机选择其中一种低表达miRNA(miR-125b),采用Lipofectamine2000进行转染,其中实验组1转染miR-125bmimics以过表达miR-125b,其阴性对照实验组2转染mimics-NC,验证过表达miR-125b 7 d后对rhBMP-2诱导的比格犬BMSCs成骨分化的影响. 结果 成功建立比格犬BMSCs培养方法;rhBMP-2诱导比格犬BMSCs成骨分化7d后,进行Q-PCR筛选,获得表达差异相对于对照组达到2倍以上的miRNAs 41个,其中表达上调的有13个,表达下调的有28个;实验组1相对于实验组2,细胞中miR-125b表达上调4.13倍(P＜0.05).转染7d后,ALP染色结果显示:实验组1细胞质中深蓝色粗大颗粒明显少于实验组2. 结论 采用Q-PCR方法筛选比格犬BMSCs成骨分化的miRNAs系统高效、准确.筛选获得的miRNAs中,miR-125b过表达能够显著抑制比格犬BMSCs的成骨分化.     

微RNA-129-5p靶向Fas相关死亡功能域蛋白基因对体外培养人椎间盘髓核细胞凋亡的影响

目的研究微RNA-129-5p(miR-129-5p)靶向Fas相关死亡功能域蛋白(FADD)基因对人椎间盘髓核细胞(hNPC)凋亡的影响,并探讨其作用机制。方法运用脂质体法将miR-219-5p抑制子转染至hNPC中抑制miR-219-5p表达,将pcDNA-FADD转染至hNPC中使FADD过表达,将miR-219-5p抑制子和FADD siRNA共转染至hNPC中抑制miR-219-5p和FADD表达。采用流式细胞术检测各组细胞凋亡率,蛋白质印迹法检测抑制miR-219-5p表达后hNPC细胞中FADD、半胱氨酸蛋白酶-3(Caspase-3)、Bcl-2和Bax蛋白表达量。通过Targetscan软件预测miR-129-5p和FADD靶向结合位点,采用双荧光素酶报告基因实验检测二者的靶向关系。结果抑制miR-219-5p、过表达FADD均可明显促进hNPC凋亡。Targetscan软件预测发现FADD 3′-UTR上存在miR-219-5p的结合位点,双荧光素酶报告基因实验证实miR-129-5p和FADD具有靶向结合关系。抑制miR-219-5p的表达后,hNPC中FADD表达上调,同时促凋亡蛋白Caspase-3表达上调,抑凋亡蛋白Bcl-2表达下调。抑制FADD可逆转miR-219-5p低表达对hNPC凋亡的促进作用。结论低表达miR-219-5p可促进hNPC凋亡,其机制可能与miR-129-5p靶向FADD有关。     

正弦电磁场对高糖环境下大鼠骨髓间充质干细胞分化的影响

目的探讨正弦电磁场对高糖环境下大鼠BMSCs分化的影响,并探讨其中可能的分子机制。方法贴壁筛选法分离、培养大鼠BMSCs,将第三代细胞分为暴磁组、高糖组、高糖暴磁组及对照组。高糖组采用高糖培养基(葡萄糖浓度为15 mmol/L),电磁场组每天给予1 mT、50 Hz正弦电磁场刺激2 h。刺激21 d后采用茜素红染色、油红O染色观察各组在成骨和成脂分化上的差异,刺激7 d后Real-time PCR检测成骨/成脂相关基因Runx2、ALP、Id4、PPARγ、aP2的表达变化。结果暴磁组钙结节形成能力较对照组增强、成骨相关基因表达增高,高糖组形成脂滴能力增强、成脂相关基因表达增高,高糖暴磁组成骨和成脂基因表达均有增高,但前者更为明显。结论正弦电磁场对高糖环境下的大鼠骨髓间充质干细胞有促进成骨、间接抑制成脂分化的作用,其机制可能与通过上调关键分子Id4有关。     

miR-135通过打靶PRKD3对黑色素瘤细胞增殖和迁移的作用

目的探讨miR-135通过打靶PRKD3对黑色素瘤细胞增殖和迁移的作用。方法通过MTT实验检测miR-135对黑色素瘤细胞增殖的作用,Transwell实验检测miR-135对黑色素瘤细胞迁移能力的作用。采用miRDB软件对miR-135的靶向蛋白进行预测分析,通过荧光素酶报告基因实验验证黑色素瘤细胞中miR-135对PRKD3的靶向作用。通过Western Blot检测miR-135对黑色素瘤细胞中PRKD3、CDK4/6和MMP2表达水平的影响。结果 miR-135能够抑制黑色素瘤细胞的增殖,当miR-135过表达后,黑色素瘤细胞的迁移能力受到抑制。miRDB软件预测分析发现,miR-135可以与PRKD3靶向作用;荧光素酶的基因实验证实,miR-135能够直接作用于PRKD3。Western Blot实验结果显示,miR-135过表达后黑色素瘤细胞中PRKD3、CDK4/6和MMP2的表达受到抑制。结论 miR-135能够通过打靶PRKD3来抑制黑色素瘤细胞的增殖和迁移能力。     

miR-124抑制结肠癌细胞增殖和侵袭与TET蛋白家族的关系

目的:探讨miR-124是否通过靶向调节TET蛋白家族的表达而抑制结肠癌细胞增殖与侵袭。方法:用双荧光素酶报告基因检测系统分别检测miR-124对TET家族(TET1、TET2、TET3)的3'UTR-荧光素酶活性的影响;用q RT-PCR与Western blot检测miR-124模拟物转染结肠癌HT29细胞后TET家族的m RNA与蛋白表达水平的变化;用MTS和Transwell实验观察HT29细胞转染miR-124模拟物及TET si RNA后增殖和侵袭能力的变化。结果:双荧光素酶报告基因检测结果显示,各TET m RNA的3'UTR均被miR-124特异性结合,其荧光素酶活性被明显抑制(均P0.05);转染miR-124模拟物后的HT29细胞TET的m RNA与蛋白表达水平明显减低(均P0.05);HT29细胞转染miR-124模拟物或TET si RNA后,增殖和侵袭能力均明显降低(均P0.05)。结论:miR-124可能通过直接靶向调控TET基因的表达,而抑制结肠癌细胞增殖和侵袭。     

腹膜间皮细胞过氧化物酶体增殖物活化受体γ的表达及其配体对CD40和细胞间黏附分子1的影响

目的观察过氧化物酶体增殖物活化受体γ（PPAR-γ）在大鼠腹膜间皮细胞（RPMCs）中的表达以及脂多糖（LPS）的调节作用，并探讨PPAR-γ天然配体15d-PGJ2及人工合成配体ciglitazone对RPMCs表达CD40和ICAM-1的影响。方法分离及培养RPMCs，常规传代及鉴定，取第2代细胞用于实验研究。LPS不同浓度（0．1、1．0、10、50及100μg／ml）、LPS（1μg／ml）处理后不同时间点及15d-PGJ2（3μmol／L）、ciglitazone（10μmol／L）作用细胞36h后收集细胞。RT-PCR检测PPAR-γ、CD40以及ICAM-1 mRNA表达。免疫细胞化学检测PPAR-γ在RPMCs中的分布。Western印迹检测PPAR-γ及ICAM-1蛋白表达。结果（1）常规培养的RPMCs表达一定量PPAR-γ，表达部位主要分布于RPMCs细胞核内，在细胞浆微弱表达。（2）随着LPS浓度逐渐增大，PPAR-γ蛋白表达水平呈逐渐增高的趋势，LPS浓度为10μg／ml时其表达为最高峰。LPS（1μg／ml）作用12h时PPAR-γ蛋白表达最强，PPAR-γ1表达高于PPAR-γ2；之后显著降低，持续至72h。（3）LPS刺激后RPMCs CD40mRNA表达显著增强；15d-PGJ2、ciglitazone显著降低CD40 mRNA表达（P均〈0．01）。（4）LPS刺激后RPMCs ICAM-1蛋白表达显著增加：15d-PGJ2增加LPS介导的ICAM-1 mRNA表达（P〈0.01），但显著抑制ICAM-1蛋白表达（P〈0．05）。ciglitazone对LPS介导的ICAM-1 mRNA和蛋白表达均有显著抑制作用（P均〈0．05）。结论RPMCs结构性表达PPAR-γ。LPS调节PPAR-γ表达呈现先增强后抑制趋势。PPAR-γ配体可显著抑制LPS介导的CD40mRNA和ICAM-1蛋白的表达。提示RPMCs功能性表达PPAR-γ．可能通过负性调节炎症介质分泌而参与腹腔局部防御。     

microRNA-126靶向PIK3R2调控肝癌细胞SMMC-7721的增殖和凋亡

【摘要】 目的 研究microRNA-126(miR-126)对肝癌细胞SMMC-7721迁移能力的影响以及对靶基因PIK3R2表达的影响。方法 通过慢病毒转染肝癌细胞株SMMC-7721使其过表达miR-126,利用CCK-8法检测细胞增殖能力。流式细胞术检测细胞凋亡;采用实时定量PCR和蛋白印迹检测细胞PIK3R2表达水平的变化,并通过荧光素酶实验验证miR-126与PIK3R2基因的直接调控关系。结果 与对照组相比,转染miR-126组的SMMC-7721细胞的增殖能力减弱,凋亡增加。过表达miR-126后,SMMC-7721细胞PIK3R2的蛋白表达下调(P=0.0135)。荧光素酶报告基因实验显示,miR-126能明显抑制PIK3R2-3’UTR的荧光素酶活性(P=0.0016)。结论〓过表达miR-126可能通过靶向降低PIK3R2基因的蛋白表达,抑制肝癌细胞的迁移。     

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.