巨噬细胞Bruton酪氨酸激酶基因特异性敲除减轻糖尿病小鼠肾脏损害的作用及机制

目的探讨巨噬细胞Bruton酪氨酸激酶(Btk)基因特异性敲除对糖尿病小鼠肾脏损害的作用及机制。方法选用巨噬细胞Btk基因特异性敲除(Btk-/-)小鼠和C57BL/6N小鼠链脲菌素(STZ,50 mg/kg)造模成功后随机分为正常组、糖尿病组、Btk-/-组和Btk-/-糖尿病组。12周后测定小鼠一般指标,观察肾组织病理学改变,免疫荧光检测肾组织巨噬细胞标志物CD68表达,免疫组化检测足细胞标志物WT1和Nephrin的表达,Western印迹检测细胞外基质纤维连接蛋白(FN)、IV型胶原(IV-Col)及转化生长因子β1(TGF-β1),巨噬细胞激活标志物诱导型一氧化氮合酶(iNOS)、磷酸化(p)-Btk,炎性因子白细胞介素1β(IL-1β)、肿瘤坏死因子α(TNF-α)和丝裂原活化蛋白激酶(MAPK)信号通路p-p38MAPK、p-JNK、p-ERK以及核因κB(NF-κB)通路p-p65、p-IκB蛋白水平变化;实时荧光定量PCR检测炎性因子IL-1β、TNF-α、单核细胞趋化蛋白1(MCP-1)mRNA表达。结果与糖尿病组相比,Btk-/-糖尿病组尿白蛋白明显减少,肾组织损伤明显减轻,肾脏巨噬细胞CD68表达明显减少,足细胞标志物WT1及Nephrin表达明显增加,细胞外基质FN、IV-Col及TGF-β1表达明显减少,炎性因子IL-1β、TNF-α及MCP-1表达明显降低,p-JNK、p-ERK、p-p38MAPK及p-p65、p-IκB表达明显下调(均P<0.05)。结论巨噬细胞Btk特异性敲除可能通过MAPK、NF-κB通路降低炎性因子的表达从而对糖尿病小鼠肾脏起到保护作用。     

MLK3-MKK3/6-p38MAPK信号转导通路在大鼠内毒素性急性肺损伤中的作用

目的 探讨MLK3-MKK3/6-p38MAPK信号转导通路在大鼠内毒素性急性肺损伤中的作用.方法 健康成年雄性SD大鼠78只,体重200～250 g,随机分为4组:对照组(C组,n=6)、急性肺损伤组(ALI组,n=24)、MLK3抑制剂K252a组(MK组,n=24)和p38MAPK特异性抑制剂SB203580组(MS组,n=24).ALI组尾静脉注射内毒素5 mg/kg制备大鼠急性肺损伤模型,C组给予等容量生理盐水,MK组和MS组于注射内毒素前30 min经尾静脉分别注射K252a 75μg/kg、SB203580 10 mg/kg.ALI组、MK组和MS组于注射内毒素后1、3、6、12 h(1-4)时各组随机取6只大鼠,C组于给予生理盐水后即刻处死取肺,采用ELISA法测定支气管肺泡灌洗液中TNF-α浓度,称重后计算肺湿干重比,采用Western b1ot法测定p-MLK3、p-MKK3/6及p-p38MAPK的表达,观察肺组织病理学结果.结果 与C组比较,ALI组、MK组和MS组各时点支气管肺泡灌洗液中TNF-α浓度、肺湿干重比、p-MLK3、p-MKK3/6及p-p38MAPK的表达水平升高(P＜0.01);与ALI组比较,MK组上述指标降低,MS组支气管肺泡灌洗液中TNF-α浓度、肺湿干重比、p-p38MAPK表达水平降低(P＜0.05).病理学结果显示:MK组和MS组肺组织损伤较ALI组减轻.结论 MLK3-MKK3/6-p38MAPK信号转导通路在大鼠内毒素性急性肺损伤中起重要作用.     

丙泊酚对内毒素诱导兔心肌损害的保护作用

目的探讨不同剂量丙泊酚对内毒素血症兔心肌损害的保护作用及可能的机制。方法通过连续注射内毒素复制内毒素血症动物模型。新西兰大白兔35只,雌雄不限,随机分为五组;各丙泊酚治疗组均为内毒素注入30min后予不同剂量丙泊酚持续静脉泵入。300min内观察动物的动脉收缩压(SBP),血清肿瘤坏死因子α(TNF-α),实验结束时取血测心肌肌钙蛋白I(cTnI)浓度、心肌丙二醛(MDA)浓度。结果(1)内毒素休克对照组血压呈不可逆下降,而丙泊酚能有效缓解内毒素导致的血压下降。(2)给予内毒素30min后心肌MDA、cTnI显著升高,丙泊酚治疗各组均能不同程度地逆转心肌MDA、cTnI的升高,降低血清TNF-α水平。结论早期、适量的丙泊酚对内毒素诱导的心肌损害可以起到一定的保护作用。其机制可能与丙泊酚抑制TNF-α生成、抑制体内脂质过氧化有关。     

美托洛尔对脓毒症大鼠血清心肌肌钙蛋白Ⅰ、肿瘤坏死因子α及核因子κB的影响

目的 探讨美托洛尔对脓毒症大鼠心肌的作用及可能的作用机制.方法 选择健康雄性SD大鼠18只,随机均分为三组:盲肠结扎加穿孔(CLP)组、美托洛尔干预(M)组和假手术(C)组.M组于CLP后2 h,经尾静脉给予美托洛尔0.05 mg冲击量,继以0.2 mg·kg-1·h-1至CLP 5 h;C组开腹后不做任何处理.用晦联免疫吸附试验(ELISA)榆测血清心肌肌钙蛋白Ⅰ(cTnI)和肿瘤坏死因子α(TNF-α),同时心肌组织用免疫组化半定量法观察核因子κB(NF-κB)的变化.结果 M组、C组血清cTnI、TNF-α及心肌NF-κB均低于CLP组(P<0.05);M组血清cTnl与血清TNF-α、心肌NF-κB之间均呈正相关.结论 美托洛尔有保护脓毒症大鼠心肌损伤的作用,其机制与抑制TNF-α及NF-κB的表达有关.     

吸入高浓度氢气对脓毒症小鼠心肌损伤及线粒体生物合成的影响

目的评价吸入高浓度氢气对脓毒症小鼠心肌损伤及线粒体生物合成的影响。方法清洁级健康雄性C57BL/6J小鼠128只, 6～8周龄, 体质量20～25 g, 采用随机数字表法分为4组(n=32):假手术组(Sham组)、假手术+氢气组(Sham+H组)、脓毒症组(Sep组)和脓毒症+氢气组(Sep+H组)。采用盲肠结扎穿孔术建立小鼠脓毒症模型。Sham+H组和Sep+H组分别于术后1和6 h时吸入67%氢气1 h。每组随机取20只小鼠, 观察术后7 d生存情况。剩余小鼠于术后24 h时取血液标本, 采用ELISA法测定血清TNF-α、IL-1β、cTnI和CK-MB浓度;取心肌组织, HE染色后进行心肌病理评分, 采用荧光分光光度法检测线粒体膜电位(MMP), 萤光素酶法检测ATP含量, Western blot法测定过氧化物酶体增殖活化受体γ共激活因子-1α(PGC-1α)、核呼吸因子2 (NRF2)、线粒体转录因子A(TFAM)的表达。结果与Sham组比较, Sep组生存率降低, 血清TNF-α、IL-1β、cTnI和CK-MB浓度和心肌病理评分升高, MMP和ATP含量降低, 心肌组...     

盐酸戊乙奎醚对心脏瓣膜置换术患者CPB期间心肌NF-κB活性及血浆TNF-α水平的影响

目的 探讨盐酸戊乙奎醚对心脏瓣膜置换术患者CPB期间心肌NF-κB活性及血浆TNF-α水平的影响.方法 择期CPB下行心脏瓣膜置换术的患者45例,性别不限,年龄18～64岁,体重指数20～22 kg/m~2,NYHA心功能分级Ⅱ或Ⅲ级,随机分为3组(n=15):对照组(C组)和不同剂量盐酸戊乙奎醚组(P_1组和P_2组).P_1组和P_2组于手术开始即刻由中心静脉分别注射盐酸戊乙奎醚0.05和0.1mg/kg,C组给予等容量生理盐水.于CPB开始前和CPB期间测定心肌NF-κB的活性和血浆TNF-α及心肌肌钙蛋白I(cTnI)的浓度,并观察心肌组织病理学结果.结果 与CPB开始前比较,三组CPB期间血浆TNF-α和cTnI的浓度升高,心肌NF-κB活性增强(P＜0.01);与C组比较,P_1组和P_2组CPB期间血浆TNF-α和cTnI的浓度降低,心肌NF-κB活性减弱(P＜0.01);P_1组和P_2组CPB期间血浆TNF-α、cTnI的浓度和心肌NF-κB活性比较差异无统计学意义(P＞0.05).P_1组和P_2组心肌病理学损伤较C组减轻.结论 CPB前静脉注射盐酸戊乙奎醚0.05、0.1 mg/kg可减轻心脏瓣膜置换术患者心肌再灌注损伤,其机制与抑制心肌NF-κB活性和血浆TNF-α浓度的升高,从而减轻炎性反应有关.     

NF-κB诱骗寡核苷酸对内毒素性肝损伤的保护作用和机制

目的探讨NF-κB诱骗寡脱氧核苷酸对大鼠内毒素性肝损伤的保护作用及其机制。方法60只SD大鼠随机分为对照组、内毒素(LPS)组、诱骗寡核苷酸(decoy ODNs)处理组。取各组大鼠肝组织检测NF-κB蛋白结合活性(EMSA),观察组织病理学改变(光镜)及肝细胞凋亡(TUNEL)。取静脉血检测AST(自动生化仪)以及TNF-α,IL-6的表达水平(ELISA)。结果与对照组相比,内毒素组NF-κB活性明显升高,诱发大量肝细胞凋亡,肝脏损伤明显;同时血清AST,TNF-α及IL-6明显升高(P0.01)。与内毒素组相比,NF-κB诱骗寡核苷酸处理组NF-κB活性受抑制(P0.01)、肝脏组织病理学改变和肝细胞凋亡明显减轻,血清中TNF-α和AST表达水平降低(P0.01),但IL-6表达与内毒素组差异无统计学意义(P0.05)。结论NF-κB诱骗策略能高效抑制NF-κB的活性,抑制其下游有害细胞因子的产生,从而减轻内毒素性肝损伤。     

不同时机迷走神经电刺激后处理对大鼠心肌缺血再灌注损伤的影响

目的 评价迷走神经电刺激后处理减轻大鼠心肌缺血再灌注损伤的适宜时机.方法 选择SPF级雄性SD大鼠120只,8周龄,体重290～ 320 g,采用随机数字表法,将其分为6组(n=20):假手术组(S组);缺血再灌注组(I/R组)结扎冠状动脉左前降支30 min,再灌注120 min;不同时机迷走神经电刺激后处理组(P1-4组):于心肌缺血15 min(P1组)、再灌注即刻(P2组)、30 min(P3组)、60 min(P4组)时对右侧迷走神经实施电刺激(波宽1 ms、频率10 Hz、电压1～2V),持续时间30 min,其余处理同I/R组.于缺血再灌注期间记录HR和SP,计算二者乘积(RPP).于再灌注120 min时采集颈静脉血样,采用ELISA法检测血清cTnI、CK-MB、TNF-α、高迁移率族蛋白-1(HMGB-1)、细胞间粘附分子-1(ICAM-1)、IL-1、IL-6和IL-10的浓度;取心肌组织测定心肌梗死范围,采用ELISA法检测缺血区心肌TNF-α、HMGB-1、ICAM-1、IL-1、IL-6和IL-10的含量.于再灌注30 min内记录室性心律失常的发生情况,并评分.结果 与S组比较,I/R组和P1-4组心肌梗死范围增大,血清cTnI、CK-MB浓度升高,I/R组血清TNF-α、HMGB-1、ICAM-1、IL-1和IL-6浓度升高,P2-4组血清HMGB-1、ICAM-1、IL-1和IL-6浓度升高,TNF-α浓度降低,P1组血清IL-10浓度升高,TNF-α浓度降低(P＜0.05),HMGB-1、ICAM-1、IL-1和IL-6浓度差异无统计学意义(P＞0.05).与I/R组比较,P1-4组心肌梗死范围减小、血清cTnI、CK-MB、血清和心肌TNF-α、HMGB-1、ICAM-1、IL-1和IL-6水平降低,P1组心肌IL-10含量升高,RPP、室性心律失常的发生率和评分降低(P＜0.05).与P1组比较,P2-4组RPP、室性心律失常的发生率和评分、血清HMGB-1、ICAM-1浓度升高,心肌ICAM-1含量升高,P3组心肌TNF-α、IL-1含量升高,P4组心肌梗死范围增大,血清cTnI、CK-MB、血清和心肌TNF-α、HMGB-1、ICAM-1、IL-1和IL-6水平升高,IL-10含量降低(P＜0.05).结论 心肌缺血15 min时行迷走神经电刺激是其减轻心肌缺血再灌注损伤的适宜时机.     

异丙酚对机械通气相关肺损伤大鼠肺组织p38MAPK信号通路的影响

目的 探讨异丙酚对机械通气相关肺损伤大鼠肺组织p38丝裂原活化蛋白激酶(p38MAPK)信号通路的影响.方法 雄性清洁级Wistar大鼠30只,体重230～300 g,2～3月龄,采用随机数字表法,将大鼠随机分为3组(n=10):对照组(C组)保留自主呼吸;机械通气组(V组)和异丙酚组(P组)行机械通气4h,P组在机械通气开始时静脉注射异丙酚5 mg/kg,机械通气期间以10mg·kg-1 ·h-1的速率静脉输注异丙酚.于机械通气15 min、1h、2h和4h时记录MAP,并采集股动脉血样,进行动脉血气分析,记录PaO2;机械通气结束时,测定支气管肺泡灌洗液(BALF)中总蛋白、TNF-α和巨噬细胞炎性蛋白-2(MIP-2)的浓度;取肺组织,测定湿干重比(W/D比)、MDA含量、SOD活性、细胞间粘附分子-1(ICAM-1)和p38MAPK、磷酸化p38MAPK(p-p38MAPK)蛋白的表达水平,计算p-p38MAPK/p38MAPK,并观察病理学结果,进行肺损伤评分.结果 与C组比较,V组和P组肺损伤评分、W/D比、肺组织MDA含量、ICAM-1表达、BALF中总蛋白浓度、TNF-α和MIP-2浓度和肺组织p-p38MAPK蛋白表达水平和p-p38MAPK/p38MAPK升高,V组肺组织SOD活性降低(P＜0.05),P组SOD活性差异无统计学意义(P＞0.05);与V组比较,P组肺损伤评分、W/D比、肺组织MDA含量、ICAM-1表达、BALF中总蛋白浓度、TNF-α和MIP-2浓度和肺组织p-p38MAPK蛋白表达和p-p38MAPK/p38MAPK降低,肺组织SOD活性、MAP和PaO2升高(P＜0.05).三组肺组织p38MAPK蛋白表达差异无统计学意义(P＞0.05).结论 异丙酚可能通过抑制p38MAPK信号转导通路的活化减轻大鼠机械通气相关肺损伤.     

地塞米松对内毒素性急性肺损伤大鼠肺组织MKP-1表达的影响

目的 评价地塞米松对内毒素性急性肺损伤大鼠肺组织丝裂原活化蛋白激酶磷酸酶-1(MKP-1)表达的影响.方法 成年雄性SD大鼠54只,体重180～ 230 g,采用随机数字表法,将其随机分为3组:对照组(C组,n=6)、急性肺损伤组(ALI组,n=24)和地塞米松组(D组,n=24).ALI组和D组尾静脉注射LPS 5 mg/kg制备大鼠急性肺损伤模型,C组给予等容量生理盐水,D组于注射LPS前30 min时腹腔注射地塞米松6 mg/kg.C组于注射生理盐水后1 h(T1)时,ALl组和D组分别于注射LPS后1、3和6 h(T1-3)时,随机处死8只大鼠,取肺组织,检测MKP-1和磷酸化p38丝裂原活化蛋白激酶MAKP(p-p38MAPK)的表达.T3时回收支气管肺泡灌洗液(BALF),测定蛋白和TNF-α的浓度;观察肺组织病理学结果.另取32只SD大鼠,体重180～ 230 g,采用随机数字表法,将其随机分为2组(n=16):急性肺损伤组(ALI1组)和地塞米松组(D1组),处理方法同上.观察48 h内大鼠生存情况.结果 与C组比较,ALI组BALF中蛋白和TNF-α的浓度升高,T1-3时p-p38MAKP表达上调,T2.3时MKP-1表达下调,D组BALF中TNF-α浓度升高,T1-3时p-p38MAKP和MKP-1表达上调(P＜0.05);与ALI组比较,D组BALF中蛋白和TNF-α的浓度下降,T1-3时p-p38MAKP表达下调,MKP-1表达上调(P＜0.05),病理学损伤减轻.D1组大鼠生存率高于ALI1组(P＜0.05).结论 地塞米松减轻大鼠内毒素性急性肺损伤的机制与上调肺组织MKP-1的表达,抑制p38MAPK的磷酸化,降低炎性反应有关.     

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.     

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.     

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.     

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.     

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.     

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.