MMP-2、12在兔脊髓损伤中的表达及与损伤程度的相关性研究

目的观察兔损伤段脊髓内MMP-2、12的表达及与损伤程度、损伤后时间点的相关性。方法将135只兔随机分为全瘫组(A组)、不全瘫组(B组)和假手术对照组(C组),每组45只。A、B组采用Allen打击法建立不同程度脊髓损伤模型,C组仅行椎板切除术。分别于致伤后6h、24h、48h、7d和14d采用免疫组织化学染色法检测兔脊髓组织中MMP-2表达,实时荧光定量PCR法检测兔脊髓组织中MMP-12的表达;运用改良Tarlov评分评价术前1h,术后麻醉清醒后6h,损伤后24h、48h、7d、14d兔后肢运动功能。结果(1)三组在各时间点均有MMP-2、12表达,但同一时间点A、B组与C组比较,差异有统计学意义(P0.05);伤后24h、48h、7dA组的表达高于B组,差异具有统计学意义(P0.05),C组各时间点表达均维持在较恒定水平。脊髓损伤后6hMMP-2、12表达增加,伤后24h达高峰,直至7d仍有MMP-2、12的高表达。(2)各时间点兔后肢运动功能评分C组明显高于A、B组,A组同时间点评分低于B组,差异具有统计学意义(P0.05);A、B组不同时间点MMP-2阳性细胞表达率和MMP-12实时荧光定量CT值与兔Tarlov评分的相关系数分别为r=-0.887,P=0.000和r=-0.841,P=0.002。结论兔脊髓损伤后MMP-2、12的表达明显升高,且与脊髓损伤程度呈负相关。     

加巴喷丁联合吗啡治疗大鼠神经病理性疼痛的疗效

目的 观察加巴喷丁联合吗啡治疗L5神经结扎(SNL)大鼠神经病理性疼痛的疗效及其对腰段脊髓炎性细胞因子表达的影响.方法 雄性SD大鼠24只行SNL术后,随机均分为四组,在术后第5天分别接受加巴喷丁100 mg/kg(G组)、吗啡3.0 mg/kg(M组)和加巴喷丁50 mg/kg联合吗啡1.5 mg/kg(GM组)、生理盐水(NS组).记录术前1 d、术后第5天给药前和给药后2、4、6 h左后肢热痛阈(PWL).然后取大鼠腰段脊髓,检测其肿瘤坏死因子α(TNF-α)、白细胞介素(IL)-6和IL-10的表达.结果 与术前1 d比较,术后第5天NS组各时点和G、M、GM组给药前左后肢PWL缩短(P<0.01).与NS组各时点比,G、M、GM组给药后2 h,G、GM组给药后4 h,CM组给药后6 h左后肢PWL延长(P<0.05或P<0.01).与给药前比较,G组给药后2、4 h,M组给药后2 h,GM组给药后2、4、6 h左后肢PWL延长(P<0.05或P<0.01).与NS组比较,GM组TNF-α、IL-6表达下降,IL-10表达上升(P<0.05或P<0.01).结论 加巴喷丁50 mg/kg联合吗啡1.5 mg/kg治疗L5神经结扎大鼠神经病理性疼痛的疗效优于加巴喷丁100 mg/kg或吗啡3 mg/kg.其镇痛机制可能与改变腰段脊髓炎性细胞因子表达有关.     

烟碱受体拮抗剂α-芋螺多肽Eb1.6对L_5脊神经切断大鼠热痛阈及脊髓星形胶质细胞和IL-1β表达水平的影响

目的探讨烟碱受体拮抗剂α-芋螺多肽(α-conotoxin,α-CTX)Eb1.6对L5脊神经切断(SNT)大鼠热痛阈(TWL)及脊髓IL-1β表达水平和星形胶质细胞活性的影响。方法 180~220g成年雄性SD大鼠50只,随机分为五组:假手术组(N组),SNT后分别腹腔注射α-CTX Eb1.6 0.15 nmol/kg组(E1组)、1.5nmol/kg组(E2组)、15nmol/kg组(E3组)和SNT后生理盐水对照组(C组),每组10只。在造模手术术后第7天疼痛模型稳定后开始腹腔注射相应剂量药物或生理盐水,连续用药7d。分别于术后第7天、术后第13天测定各组大鼠给药前、给药后1、2、4、7、12 h热缩爪潜伏期(TWL)。于术后第13天行为学测试结束后将各组大鼠处死取L5脊髓组织,以Western blot法测定脊髓星形胶质细胞标志物胶质纤维酸性蛋白(glial fibrillary Acidic protein,GFAP)表达水平,ELISA法测定脊髓IL-1β表达水平。结果与给药前比较,E1、E2、E3组大鼠第7天给药后1、2、4 h TWL明显延长(P0.05),给药后2h延长最明显;E1、E2、E3组大鼠第13天给药后1、2、4、7h以及E2、E3组第13天给药后12hTWL明显延长(P0.05),且均长于各组第7天相应时点的TWL(P0.05),给药后2h延长最明显;与E3组比较,E1、E2组大鼠第7天及第13天给药后2h的TWL明显缩短(P0.05),且E1组明显短于E2组(P0.05)。与N组比较,E1、E2、E3组和C组大鼠脊髓IL-1β与GFAP表达水平明显升高(P0.05);与C组比较,E1、E2、E3组脊髓IL-1β与GFAP表达水平明显下降(P0.05);与E3组比较,E1、E2组脊髓IL-1β与GFAP表达水平明显升高(P0.05),且E1组明显高于E2组(P0.05)。结论腹腔注射Eb1.6能够剂量依赖性地减轻L5脊神经切断大鼠的热痛敏且连续用药能够增强其镇痛效果。其镇痛作用可能与抑制脊髓背角星形胶质细胞活化、降低IL-1β表达水平有一定关系。     

TNF-α拮抗剂(Etanercept)治疗脊髓损伤作用机制的实验研究

目的探讨TNF-α拮抗剂Etanercept(依那西普)对继发性脊髓损伤的治疗作用和可能机制。方法建立大鼠脊髓挫伤模型,损伤后1 h对大鼠行腹腔注射5 mg/kg Etanercept或生理盐水(损伤对照组);假手术组(20只大鼠)仅行椎板切除术而无脊髓损伤,1 h后给予腹腔注射1 ml生理盐水。结果在脊髓损伤急性期(12 h、1 d、3 d),Etanercept治疗组TNF-α的蛋白表达强度明显弱于损伤对照组。与对照组相比,Etanercept治疗组TNFR1的表达在损伤后6、12 h均下降,TNFR2仅在损伤后6 h下降。损伤对照组大鼠在脊髓损伤后后肢运动功能明显受限,而Etanercept治疗组大鼠在脊髓损伤后2、4、8周,后肢BBB评分显著升高。结论 Etanercept可能通过抑制TNF-α/TNFR通路,减轻了脱髓鞘变性,促进了运动功能的恢复。     

异丙酚预先给药对大鼠局灶性脑缺血再灌注时脑组织p-JNK、MMP-9和AQP-4表达的影响

目的 评价异丙酚预先给药对大鼠局灶性缺血再灌注时脑组织磷酸化c-Jun氨基末端蛋白激酶(p-JNK)、基质金属蛋白酶-9(MMP-9)和水通道蛋白-4(AQP-4)表达的影响.方法 健康成年雄性SD大鼠72只,体重250～280g,随机分成4组(n=18):假手术组(S组);脑缺血再灌注组(IR组)于缺血前30 min腹腔注射生理盐水10ml/kg;不同浓度异丙酚预先给药组(P1组和P2组)于缺血前30 min分别腹腔注射0.5%或1%异丙酚10 ml/kg.IR组、P1组和P2组采用线栓法建立大鼠局灶性脑缺血再灌注模型,缺血2 h,再灌注24 h.大鼠清醒后,进行神经功能缺陷评分.再灌注24 h时处死大鼠,处死前1 h股静脉注射2%伊文氏蓝(EB)溶液3 ml/kg,处死后取脑组织,测定含水量、EB含量、p-JNK、MMP-9和AQP-4的表达水平.结果 与S组比较,IR组、P1组和P2组神经功能缺陷评分、脑组织含水量和EB含量升高,p-JNK、MMP-9和AQP-4的表达上调(P＜0.05);与IR组比较,P1组和P2组神经功能缺陷评分、脑组织含水量和EB含量降低,p-JNK、MMP-9和AQP-4的表达下调(P＜0.05);与P1组比较,P2组脑组织p-JNK和MMP-9的表达下调(P＜0.05),神经功能缺陷评分、脑组织含水量、EB含量和AQP-4表达差异无统计学意义(P＞0.05).结论 异丙酚预先给药可通过抑制JNK信号通路的激活,抑制脑组织MMP-9和AQP-4的表达上调,减轻大鼠局灶性脑缺血再灌注损伤.     

大鼠静脉注射异氟醚注射液的长期毒性研究

目的评价异氟醚注射液是否对大鼠各脏器、系统产生损害及损害程度和可逆程度。方法 100只 SD 大鼠随机分为生理盐水组(生理盐水3.0 ml/kg),溶媒对照组(30%脂肪乳3.0ml/kg),异氟醚注射液高剂量组(1.1 ml/kg),中剂量组(0.9 ml/kg)和低剂量组(0.7 ml/kg),每组20只.雌雄各半。每天以等容量(3.0 ml/kg)、等速度(1.5 ml/kg·10 s)静脉给药一次.连续给予30 d。期间记录动物一般情况;在给药期结束(最后一次给药后24 h)、恢复期结束(最后一次给药后两周)两时点每组各选择一半动物采血进行血液学及生化学指标检测,处死后取所有脏器及给药部组织标本行病理学检查。结果给药前、给药期结束、恢复期结束三个时点各组间体重差异无统计学意义。恢复期结束高剂量组红细胞均数的95%可信区间位于正常参考值范围内。恢复期结束五组血清尿素浓度均数的95%可信区间均未超出正常参考值范围。给药期结束和恢复期结束未发现大鼠器官特异性组织病理学损害。结论长期静脉注射异氟醚注射液未对大鼠各脏器和系统产生明显毒性损害。     

富甲烷生理盐水对大鼠急性脊髓损伤的治疗作用及剂量效应研究

目的研究富甲烷生理盐水(MS)腹腔注射对大鼠脊髓损伤的治疗作用及剂量效应关系。方法 50只雌性SD大鼠,随机取40只采用改良Allen法制作大鼠脊髓损伤模型,其余10只纳入假手术组。40只脊髓损伤大鼠随机分为脊髓损伤组、0.5 ml/kg MS组、5 ml/kg MS组、20 ml/kg MS组,每组10只。0.5 ml/kg MS组、5 ml/kg MS组、20 ml/kg MS组大鼠每12 h腹腔内注射相应剂量的MS。造模72 h后处死大鼠,迅速取出以脊髓损伤部位为中心、周围6 mm内组织,检测超氧化物歧化酶(SOD)、丙二醛(MDA)、TNF-α、IL-1β和IL-6含量。结果与假手术组比较,脊髓损伤组大鼠脊髓组织中MDA含量显著升高,而SOD活性显著降低,IL-1β、TNF-α、IL-6含量显著升高,差异有统计学意义(P 0.05)。与脊髓损伤组比较,0.5 ml/kg MS组、5 ml/kg MS组、20 ml/kg MS组MDA含量逐渐降低,SOD活性逐渐升高,IL-1β、TNF-α、IL-6含量逐渐降低,差异有统计学意义(P 0.05)。结论大鼠腹腔注射MS可以通过抑制脊髓受损节段的炎症反应、氧化应激,起到治疗脊髓损伤的作用,剂量与效应呈正相关。     

姜黄素抑制聚乙烯磨损颗粒诱导MMP-2和MMP-9表达及机制的研究

目的 观察不同剂量姜黄素对注射聚乙烯磨损颗粒小鼠air-pouch模型囊壁组织MMP-2、MMP-9表达的影响,并探讨姜黄素干预磨损颗粒诱发炎性反应的作用机制.方法 取健康昆明系小鼠72只,参照Yang等方法构建air-pouch动物模型,于背部囊腔中注入3 mL浓度为1×108个/mL高分子聚乙烯颗粒悬液.动物模型随机分为3组(n=24),对照组(A组):生理盐水灌胃0.6 mL/d;低剂量实验组(B组):浓度为1.6 mg/mL姜黄素溶液灌胃0.6 mL/d:高剂量实验组(C组):浓度为3.2 mg/mL姜黄素溶液灌胃0.6 mL/d.术后观察动物一般情况,于给药后3、7及14 d,每组取8只小鼠背部囊壁组织行大体、组织学观察及免疫组织化学、RT-PCR、Western blot检测.结果 各组小鼠均存活至实验完成.各组小鼠背部皮下均可见一白色的囊腔组织,各时间点A组囊腔直径大于B、C组,C组小于B组.镜下观察A组炎性反应强于B、C组,7、14 d时C组明显弱于B组.给药后3 d,B、C组囊壁组织中MMP-2、MMP-9表达与A组差异无统计学意义(P＞0.05);7、14 d时差异有统计学意义(P＜0.05).给药后7 d C组MMP-2表达与B组比较差异无统计学意义(P＞0.05),14 d时两者差异有统计学意义(P＜0.05);7、14 d两组MMP-9表达差异有统计学意义(P＜0.05).给药后NF-kB P65因子的核转位受到明显抑制,在7、14 d时3组间差异具有统计学意义(P＜0.05),3 d时差异无统计学意义(P＞0.05).结论 聚乙烯磨损颗粒可刺激囊壁组织MMP-2、MMP-9的表达.姜黄素可以抑制air-pouch动物模犁囊壁组织中MMP-2、MMP-9的表达,MMP-2、MMP-9表达可能受NF-kB活化的调节.     

表没食子儿茶素没食子酸酯对大鼠脊髓损伤后神经功能恢复的影响

【摘要】 目的：研究经蛛网膜下腔给予表没食子儿茶素没食子酸酯（epigallocatechin gallate,EGCG）对大鼠脊髓损伤（spinal cord injury,SCI）后神经功能恢复的影响及其作用机制。方法：成年雌性SD大鼠40只,随机分为4组,每组10只,假手术组（A组）仅切除椎板;对照组（B组）SCI后,蛛网膜下腔注射同体积载体溶液;10mg/kg EGCG治疗组（C组）SCI后经蛛网膜下腔注射EGCG 10mg/kg;20mg/kg EGCG治疗组（D组）SCI后经蛛网膜下腔注射EGCG 20mg/kg。改良Allen法（40g·cm）制作T10节段SCI模型,L4水平蛛网膜下腔注射EGCG或载体溶液。术前、术后1d、术后3d及术后1、2、3、4周进行盲法BBB评分、斜板试验;术后4周时处死大鼠,病理学检查（Luxol fast blue染色）观察脊髓损伤部位残余髓鞘情况;免疫组化及Western blot法检测胶质细胞源性营养因子（GDNF）、脑源性神经营养因子（BDNF）、Bcl-2和Bax的表达水平。结果：A组术前及术后各时间点BBB评分均为21分,斜板试验角度无明显变化;术后各时间点B、C组和D组BBB评分及斜板试验角度均小于A组（P＜0.05）;术后1d、3d时,B、C组和D组BBB评分以及斜板试验角度无统计学差异（P＞0.05）;术后1、2、3、4周时,C、D组的BBB评分及斜板试验角度均大于B组（P＜0.05）,C组的BBB评分及斜板试验角度与D组比较均无统计学差异（P＞0.05）。术后4周时,B、C、D组大鼠脊髓损伤部位的髓鞘残余面积均小于A组（P＜0.05）,C、D组明显大于B组（P＜0.05）,在损伤脊髓中心D组明显大于C组（P＜0.05）。术后4周时免疫组化检查,B、C、D组的BDNF、GDNF、Bcl-2和Bax的阳性表达强于A组,C、D组的BDNF、GDNF和Bcl-2的阳性表达强于B组,Bax的阳性表达弱于B组。术后4周时Western blot法检测,B、C、D组的BDNF、GDNF、Bcl-2和Bax的表达高于A组（P＜0.05）;C、D组的BDNF和GDNF表达明显高于B组（P＜0.05）,C组与D组无统计学差异（P＞0.05）;C、D组的Bcl-2表达明显高于B组（P＜0.05）,C组与D组比较无统计学差异（P＞0.05）;C组和D组的Bax表达明显低于B组（P＜0.05）,D组明显低于C组（P＜0.05）。结论：EGCG可有效促进大鼠SCI后的神经功能恢复,其机理可能与髓鞘的丢失减少、神经营养因子BDNF和GDNF的表达上调及细胞凋亡被抑制等有关。     

反复注射不同剂量氯胺酮对幼年小鼠认知功能的影响

目的 探讨反复注射不同剂量氯胺酮对幼年小鼠认知功能的影响.方法 21 d龄小鼠50只,体重10～15 g,随机分为5组(n=10),正常对照组(c组);生理盐水组(N组)腹腔注射生理盐水0.1 ml,1次/d,连续7 d;不同剂量氯胺酮组(K1组、K2组、K3组)分别腹腔注射氯胺酮25、50、100 mg/kg,1次/d,连续7 d.于给药结束后1 d时测定学习功能,于给药结束后2 d时测定记忆功能.记忆功能测定结束后每组处死4只小鼠,采用免疫组化法测定海马脑源性神经营养因子(BDNF)表达;处死6只小鼠,采用免疫印记法测定海马BDNF蛋白表达.结果 与C组比较,N组和K1组学习记忆功能减退,BDNF蛋白表达下调(P＜0.05或0.01),K2组和K3组差异无统计学意义(P＞0.05);N组和K1组学习记忆功能和BDNF蛋白表达差异无统计学意义(P＞0.05).结论 50、100 mg/kg(连续7 d反复给药)氯胺酮对幼年小鼠认知功能无影响,25 mg/kg(连续7 d反复给药)氯胺酮可降低认知功能.     

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.     

Is the recovery profile of mivacurium independent of the rate of decay of its plasma concentration in patients with normal plasma cholinesterase activity?

Background: The duration of action of muscle relaxants is poorly correlated to the rate of decay of their plasma concentration. The plasma concentration of mivacurium may rapidly decrease below its active concentration because of the extensive hydrolysis of mivacurium. By inflating a tourniquet on one upper limb for 3 min after the administration of atracurium, mivacurium or vecuronium, we studied the influence of the initial decline of their plasma concentration on their effect. Methods: In 50 patients anaesthetised with thiopental, isoflurane and fentanyl, the effect of bolus doses of 0.15 or 0.25 mg . kg^?1 mivacurium (MIV 15, MIV 25), 0.3 or 0.5 mg . kg^?1 atracurium (ATR 30, ATR 50) and 0.06 or 0.1 mg . kg^?1 vecuronium (VEC 06, VEC 10) were measured on both arms (evoked response of the adductor pollicis to train-of-four stimulation every 12 s), a tourniquet being applied on one arm just before and during 3 min after the muscle relaxant bolus. Results: Tourniquet inflation of 3 min almost abolished the neuromuscular effect of mivacurium. In the vecuronium groups and in the ATR 50 group, tourniquet inflation did not modify the maximum degree of depression of the twitch response. Also, the duration of action of vecuronium was unaffected by the tourniquet. In the ATR 30 group, times to return of the twitch response to 25% (duration 25%) and 75% (duration 75%) of control response were significantly shorter in the cuffed arm, 23 min vs 27 min, and 41 min vs 45 min, respectively. In the ATR 50 group, only duration 25% was significantly shorter in the cuffed arm (41 min vs 45 min). Conclusion: The results suggest that the rate of decline of the plasma concentration of mivacurium is so rapid, that a very low and almost clinically ineffective concentration is present as soon as 3 min after its administration. The results also indicate that the recovery from a mivacurium-induced neuromuscular blockade is not influenced by the rate of decay of its plasma concentration in patients with genotypically normal plasma cholinesterase.     

Membranes in Artificial Organs

Abstract: Membrane processes play a pivotal and enabling role in modern replacement therapy for acute and chronic organ failure and in the management of immunologic diseases. In fact, virtually all contemporary extracorporeal blood purification methods employ membrane devices, and the next generation of artificial organs and tissue engineering therapies are almost certain to be similarly grounded in membrane technology. In this short essay, we comment on the similarities and differences among synthetic membranes and their natural counterparts and also provide a critical overview of the demographics and technology of hemodialysis, hemofiltration, apheresis, oxygenation, and emerging membrane technologies and applications.     

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.     

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.