异丙酚对大鼠油酸性急性肺损伤的保护作用

目的观察异丙酚对大鼠油酸性急性肺损伤(ALI)的保护作用及其机制。方法 40只成年雄性 SD 大鼠,体重：250～290g,随机分成5组：正常对照组(Ⅰ组)、ALI 组(Ⅱ组)、4mg·kg~(-1)·h~(-1) 异丙酚治疗组(Ⅲ组)、8mg·kg~(-1)·h~(-1)异丙酚治疗组(Ⅳ组)、16mg·kg~(-1)·h~(-1)异丙酚治疗组(Ⅴ组)；Ⅱ～Ⅴ组静脉注射油酸250μl·kg~(-1)制备大鼠 ALI 模型,然后Ⅲ～Ⅴ组持续静脉输注异丙酚4h 时处死大鼠。测定肺组织 MDA 含量及 MPO、SOD 活性；透射电镜观察肺组织超微结构变化；免疫组化及流式细胞术测定肺组织白介素(IL)-18、IL-10水平；电泳迁移率变动分析技术测定肺组织 NF-(?)B 的表达。结果电镜显示Ⅱ组肺泡Ⅱ型上皮细胞线粒体、粗面内质网及嗜锇性板层小体损伤；Ⅲ～Ⅴ组肺泡Ⅱ型上皮细胞细胞器损伤均有不同程度改善,尤以Ⅳ组效果明显。与Ⅰ组比较,Ⅱ组肺组织 MDA、IL-10、 IL-18、NF-(?)B 水平升高,MPO、SOD 活性降低(P＜0.05)；静脉输注异丙酚使 ALI 大鼠肺组织 MPO、SOD 活性升高,MDA、IL-18、NF-(?)B 水平降低,IL-10水平升高(P＜0.05)。结论 4～16mg·kg~(-1)·h~(-1)异丙酚均可抑制油酸性 ALI 时的氧化应激反应,阻断 NF-(?)B 的活化,减轻肺部炎性反应,对油酸性 ALI 起到一定的保护作用,8mg·kg~(-1)·h~(-1)剂量效果较好。     

异丙酚对内毒素性急性肺损伤大鼠中性粒细胞NF-κB活化的影响

目的 探讨异丙酚对内毒素性急性肺损伤(ALI)大鼠中性粒细胞NF-κB活化的影响.方法 健康清洁级SD大鼠60只,3月龄,体重250～350 g,雌雄不拘,随机分为5组(n=12):对照组(C组)、ALI组和不同剂量异丙酚组(Pl组、P2组、P3组).ALI组经股静脉注射LPS 5 mg/kg;Pl组、P2组和P3组经股静脉注射LPS 5 mg/kg后立即分别静脉输注异丙酚5、10和15 mg·kg-1·h-1,输注时间2 h;C组经股静脉注射10 ml生理盐水.异丙酚输注结束时,行肺组织病理学评分,采集颈动脉血样,测定中性粒细胞总NF-κB和活化的NF-κB的表达水平.结果 与C组比较,ALI组、P1组和P2组肺组织病理学评分和中性粒细胞活化的NF-κB表达水平升高,P3组肺组织病理学评分升高(P＜0.05);与ALI组比较,P2组和P3组肺组织病理学评分降低,P1组～P3组中性粒细胞活化的NF-κB表达水平降低(P＜0.05);P1组～P3组肺组织病理学评分和中性粒细胞活化的NF-κB表达水平依次降低(P＜0.05);各组中性粒细胞总NF-κB表达水平差异无统计学意义(P＞0.05).结论 异丙酚减轻大鼠内毒素性急性肺损伤的机制可能与抑制外周血中性粒细胞NF-κB的活化有关.     

c-Jun氨基末端激酶在大鼠内毒素性急性肺损伤中的作用

目的 评价c-Jun氨基末端激酶(JNK)在大鼠内毒素性急性肺损伤中的作用.方法 雄性成年SD大鼠80只,体重250～300 g,采用随机数字表法,将其随机分为4组(n=20):对照组(C组)、急性肺损伤组(ALI组)、SP600125组(S组)和二甲基亚砜组(D组).ALI组、S组和D组尾静脉注射LPS 5 mg/kg,C组尾静脉注射等容量生理盐水;S组和D组给予LPS后,分别尾静脉注射JNK抑制剂SP600125 30 mg/kg或二甲基亚砜0.2 ml.于给予LPS后4 h时,各组处死10只大鼠,回收支气管肺泡灌洗液(BALF)并取肺组织,采用ELISA法检测BALF中TNF-α和IL-1β的浓度,计算肺组织湿重/干重比(W/D比),观察肺组织病理学结果,并进行肺损伤评分.各组其余10只大鼠观察至给予LPS后48 h,记录大鼠生存情况.结果 与C组比较,其余各组BALF中TNF-α和IL-1β的浓度、肺组织W/D比和肺损伤评分升高,生存率降低(P<0.05或0.01);与ALI组比较,S组BALF中TNF-α和IL-1度、肺组织W/D比和肺损伤评分降低,生存率升高(P<0.01),D组差异无统计学意义(P>0.05).结论 JNK的活化参与了大鼠内毒素性急性肺损伤的发生发展.

Abstract：

Objective To evaluate the role of c-Jun N-terminal kinase (JNK) in lipopolysaccharide (LPS)-induced acute lung injury ( ALI) in rats.Methods Eighty male SD rats weighing 250-300 g were randomly divided into 4 groups ( n = 20 each) : control group (group C) ; ALI group; LPS + SP600125 (JNK inhibitor)group (group S) and LPS+ DMSO (the solvent) group (group DMSO) . ALI was induced by intravenous LPS 5mg/kg. In S and DMSO groups, SP600125 30 mg/kg and DMSO 0.2 ml were injected intravenously after LPS administration respectively. Ten animals were sacrificed by exsanguinafions at 4 h after LPS administration in each group. The broncho-alveolar lavage fluid (BALF) was colleted. The TNF-α and IL-1β concentrations in BALF were measured. The lungs were removed for microscopic examination and determination of W/D lung weight ratio. The other 10 animals in each group were observed for 48 h survival rate. Results Intravenous LPS significantly increased TNF-α and IL-1β concentrations in BALF and W/D lung weight ratio, decreased 48 h survival rate and induced histologic damage. Intravenous SP600125 30 mg/kg significantly attenuated the above-mentioned LPS-induced changes. Conclusion Activation of JNK is involved in the development of endotoxin-induced ALI in rats.     

异丙酚对内毒素性休克大鼠血管反应性的影响

目的评价异丙酚对内毒素性休克大鼠血管反应性的影响。方法40只雄性SD大鼠随机分为4组(n=10),对照组;休克组:静脉注射内毒素(LPS)15 mg·kg-1;异丙酚组:静脉注射LPS 后1 h,静脉注射异丙酚10 mg·kg-1后10 mg·kg-1·h-1持续静脉泵注4 h;5-甲氧色胺组:静脉注射LPS 后1 h,腹腔注射5-甲氧色胺10 mg·kg-1。注射LPS后6 h,各组大鼠依次静脉注射去氧肾上腺素(PE) 0.5、1、2、2.5 μg·kg-1,记录注药后平均动脉压(MAP)的增幅百分比。注射LPS后6 h,经心内穿刺取血, 测定血浆丙二醛(MDA)及一氧化氮浓度(NO2-/NO3-)。所有在体实验结束后取大鼠胸主动脉环做离体张力实验,建立去氧肾上腺素的剂量-张力反应曲线,并计算相应主动脉环最大收缩张力(Emax)、半数有效浓度(EC50)。结果休克组、异丙酚组、5-甲氧色胺组MAP增幅百分比均低于对照组(P< 0.05),异丙酚、5-甲氧色胺组MAP增幅百分比均高于休克组(P<0.05)。异丙酚组、5-甲氧色胺组血浆MDA及NO2-/NO3-浓度均低于休克组(P<0.05)。在离体实验中,休克大鼠主动脉环对PE反应的Emax及EC50与均低于对照组(P<0.05),但是异丙酚组和5-甲氧色胺组主动脉环对PE的反应均升高(P<0.05)。异丙酚组和5-甲氧色胺组主动脉收缩力均高于休克组,并且主动脉环对PE的Emax增高,EC50降低(P<0.05)。结论异丙酚可能通过减少氧自由基,抑制NO的合成,从而改善内毒素性休克大鼠的血管低反应性。     

氯胺酮对内毒素血症大鼠炎性反应及血液动力学的影响

目的观察不同剂量氯胺酮对内毒素血症大鼠炎性反应及血液动力学的影响。方法36只成年雄性Wistar大鼠随机分为6组,每组6只,A组(对照组):静脉输注生理盐水10ml·kg-1·h-1;B组:静脉注射内毒素(LPS)5mg·kg-1,1min后静脉输注生理盐水10ml·kg-1·h-1;C组:静脉注射LPS5mg·kg-1,1min后静脉输注氯胺酮0.5mg·kg-1·h-1;D组:静脉注射LPS5mg·kg-1,1min后静脉输注氯胺酮5mg·kg-1·h-1;E组:静脉注射LPS5mg·kg-1,1min后静脉输注氯胺酮50mg·kg-1·h-1;F组:静脉输注氯胺酮50mg·kg-1·h-1。记录注射LPS后30、60、90、120min时平均动脉压(MAP)和心率(HR),并于注射LPS后120min时放血处死大鼠,测定外周血单核细胞(PBMC)中NF-κB含量及血浆肿瘤坏死因子-α(TNF-α)和白细胞介素-6(IL-6)浓度。结果与基础值比较,B组注射LPS后MAP下降,HR增快,PBMC中NF-κB含量增加,血浆TNF-α、IL-6浓度升高。与B组比较,E、F组.MAP在注射LPS后120min升高,E组HR在注射LPS后90、120min、F组HR在注射LPS后60-120min降低,C、D、E组PBMC中NF-κB含量及血浆TNF-α浓度降低(P<0.05或0.01),但血浆IL-6浓度差异无统计学意义(P>0.05)。结论50mg·kg-1·h-1氯胺酮改善内毒血症大鼠血液动力学的紊乱,又可以在一定程度上抑制炎性反应,0.5、5mg·kg-1     

环腺苷酸-蛋白激酶A在大鼠内毒素性急性肺损伤时血红素加氧酶-1表达上调中的作用

目的 探讨环腺苷酸-蛋白激酶A(cAMP-PKA)在大鼠内毒素性急性肺损伤时血红素加氧酶-1(HO-1)表达上调中的作用.方法 健康清洁级雄性SD大鼠48只,体重180 ～ 220 g,2.5 ～ 3.0月龄,采用随机数字表法,将大鼠随机分为4组(n=12)∶正常对照组(C组)股静脉注射生理盐水(LPS溶媒)0.5 ml,2h后皮下注射生理盐水(H89溶媒)0.5 ml;内毒素性急性肺损伤组(ALI组)股静脉注射10 mg/kg LPS 0.5 ml,2h后皮下注射生理盐水0.5 ml; H89+内毒素性急性肺损伤组(H+ALI组),股静脉注射10 mg/kg LPS 0.5 ml,2h后皮下注射5 mg/kg H89 0.5 ml; H89组(H组)股静脉注射生理盐水0.5 ml,2h后皮下注射5 mg/kg H89 0.5 ml.静脉注射LPS后6h时处死大鼠,取肺组织,行病理学评分,测定肺组织含水量;采用Western blot法测定HO-1和PKA表达;采用荧光定量PCR法测定HO-1mRNA表达.结果 与C组比较,ALI组和H+ALI组肺组织含水量和病理学评分升高,肺组织PKA、HO-1和HO-1 mRNA表达上调(P＜0.05),H组上述各指标差异无统计学意义(P＞0.05);与ALI组比较,H+ALI组肺组织含水量和病理学评分升高,肺组织PKA、HO-1和HO-1 mRNA表达下调(P＜0.05).结论 大鼠内毒素性急性肺损伤时HO-1表达上调的机制与cAMP-PKA信号通路活化有一定关系.     

异丙酚对内毒素所致急性肺损伤大鼠肺组织TGF-β1/Smad2信号通路的影响

目的 探讨异丙酚对内毒素所致急性肺损伤大鼠肺组织转化生长因子(TGF)-β1/Smad2信号通路的影响.方法 健康雄性Wistar大鼠56只,7～8周龄,260 ～ 300 g,采用随机数字表法,将其随机分为5组:正常对照组(A组,n=8)、LPS组(B组,n=12)、异丙酚不同时点给药组(C组～E组,n=12).A组给予等容量生理盐水,B组静脉注射脂多糖8 mg/kg,C组、D组和E组分别于给予LPS前1h、给予LPS后即刻和给予LPS后1h时静脉注射异丙酚5 mg/kg,随后以10 mg· kg-1·h-1速率输注至给予LPS后5h.分别于给予LPS前即刻、给予LPS后1、3、5h时采集动脉血样,测定pH值和PaO2,随后处死大鼠,取肺组织,计算湿/干重比(W/D),测定肺组织TGF-β1 mRNA和Smad2表达.结果 与A组比较,B组和E组pH值和PaO2降低,肺组织W/D升高,TGF-β1 mRNA和Smad2表达上调(P＜0.05);与B组比较,C组和D组pH值和PaO2升高,肺组织W/D降低,TGF-β1 mRNA和Smad2表达下调,E组PaO2升高(P＜0.05).结论 异丙酚减轻内毒素所致ALI的机制与抑制TGF-β1/Smad2通路激活有关.     

丙泊酚对内毒素性急性肺损伤大鼠血清TNF-α、IL-1β及IL-10的影响

目的探讨内毒素性急性肺损伤(ALI)大鼠用丙泊酚后处理对血清肿瘤坏死因子(TNF)-α、白细胞介素(IL)-1β和IL-10影响。方法雄性SD大鼠96只,随机均分为四组,每组24只。脂多糖(LPS)致伤组(B组)、丙泊酚低剂量治疗组(C组)和丙泊酚高剂量治疗组(D组)经尾静脉注射LPS 5 mg/kg制作ALI模型;之后生理盐水对照组(A组)和B组泵入生理盐水,C、D组分别注射丙泊酚2、4 mg/kg后再分别泵入4、8 mg.kg-1.h-1。分别在制模后1、2、3、4 h抽取动脉血测定TNF-α、IL-1β及IL-10的水平。结果制模后各时点A组大鼠TNF-α、IL-1β和IL-10含量均明显低于其它三组(P<0.05或P<0.01)。制模后1、2 h B组TNF-α、IL-1β和IL-10含量明显高于C、D组(P<0.01),C组IL-1β和IL-10含量明显高于D组(P<0.05或P<0.01)。制模后3、4 h B组IL-1β和IL-10含量仍明显高于C、D组(P<0.01),C组显著高于D组(P<0.01)。结论丙泊酚可以显著抑制ALI大鼠血清TNF-α、IL-1β及IL-10上升的程度。     

右美托咪定对脂多糖诱导的脓毒症大鼠全身炎症反应和肺损伤的影响

目的观察脂多糖(LPS)对大鼠血浆和肺组织中的炎性因子和Toll样受体4(TLR4)表达的影响及右美托咪定的干预作用。方法雄性SD大鼠40只,250~300g,随机分为四组。Control组(n=10)生理盐水1ml·kg~(-1)·h~(-1)大鼠尾静脉泵注6h;DEX组(n=10)右美托咪定(负荷量6.5μg·kg~(-1)·h~(-1),10min;5μg·kg~(-1)·h~(-1)维持)大鼠尾静脉泵注6h;LPS组(n=10)经大鼠尾静脉注射7.5mg/kg的LPS后继续生理盐水泵注6h;LPS+DEX组(n=10)经大鼠尾静脉注射7.5mg/kg的LPS后泵注右美托咪定6h。以6h为实验终结点,并于此时行右心室取血和肺组织标本的制备。采用ELISA法检测血浆IL-1、IL-6、TNF-α浓度,Western blot法检测肺组织TLR4、髓样分化因子88(MyD88)、NF-κB蛋白含量;检测大鼠肺组织湿/干比(W/D);并用Murakami法评测肺损伤程度。结果与Control组比较,LPS组大鼠血浆IL-1、IL-6和TNF-α浓度明显升高,肺组织中的TLR4、MyD88、NF-κB蛋白含量明显升高(P0.01),肺W/D明显升高;LPS+DEX组上述指标差异均无统计学意义。Control组和DEX组未见明显肺损伤,LPS组肺间质水肿、炎性细胞浸润明显,LPS+DEX组肺损伤程度明显减轻(P0.01)。结论 LPS的刺激可以明显升高大鼠血浆中炎性因子以及肺组织中TLR4的表达水平,右美托咪定的干预可以减轻这一趋势,缓解大鼠的全身炎症和肺水肿的程度。     

异丙酚对大鼠缺血再灌注心肌Toll样受体4、NF-κB及血清IL-6的影响

目的 探讨异丙酚对大鼠缺血再灌注心肌Toll样受体4(TLR4)、核转录因子κB(NF-κB)和血清白细胞介素-6(IL-6)的影响.方法 健康雄性SD大鼠40只,体重200～250 g,随机分为4组,每组10只,假手术组(A组)左冠状动脉前降支只穿线;缺血再灌注组(B组)左冠状动脉前降支穿线结扎30 min后,再灌注120 min;A组和B组在缺血前10 min经股静脉注射生理盐水5 ml/kg后以5 ml·kg-1·h-1持续静脉输注至再灌注120 min;低剂量异丙酚组(C组)缺血前10 min经股静脉注射异丙酚5mg/kg后以5 mg·kg-1·h-1持续静脉输注至再灌注120 min,余处理同B组;高剂量异丙酚组(D组)缺血前10 min经股静脉注射异丙酚10 mg/kg后以10 mg·kg-1·h-1持续静脉输注至再灌注120 min,余处理同B组.再灌注120 min后,测定血清IL-6的浓度及心肌TLR4 mRNA、NF-κB蛋白的表达.结果 与A组比较,B组、C组及D组心肌TLR4 mRNA、NF-κB蛋白表达上调,血清IL-6水平升高;与B组比较,C组和D组心肌TLR4 mRNA、NF-κB蛋白表达下调,血清IL-6水平降低;与C组相比,D组心肌TLR4 mRNA、NF-κB蛋白表达下调,血清IL-6水平降低.结论 静脉注射异丙酚可抑制大鼠缺血再灌注心肌TLR4 mRNA、NF-κB的表达及血清IL-6浓度的升高,呈剂量依赖性.     

脊髓急性损伤时NO、IL-8、IL-6的表达及意义

目的 :研究脊髓急性损害早期白细胞介素 -8(IL 8) ,白细胞介素 -6(IL 6) ,一氧化氮 (NO)及一氧化氮合酶 (NOS)的变化。方法 :76例脊髓急性损害病人 ,根据Franked分类 ,分完全截瘫 (FrankedA)组 ,不完全截瘫 (FrankedB ,C和D)组 ,以ELISA法 ,硝酸还原酶法分别测IL 8、IL 6、NO、NOS的值 ,以健康体检人员作对照。结果 :IL 8、IL 6的值完全截瘫者和不完全截瘫者都显著升高 (P <0 .0 5 ) ,NO、NOS的值完全截瘫者和不完全截瘫者都显著降低 (P <0 .0 5 )。结论 :脊髓急性损害早期IL 8、IL 6显著升高 ,NO、NOS显著降低 ,脊髓急性损害早期IL 8、IL 6、NO参与了脊髓继发性损害。     

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.     

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.