增殖型腺病毒介导的人内皮抑素基因治疗胰腺癌

目的 观察携带人内皮抑素基因的双重调控增殖型腺病毒(AdTPHre-hEndo)对胰腺癌的治疗作用.方法 通过病毒重组技术将人内皮抑素基因克隆入双重调控增殖型腺病毒基因组中,获得腺病毒滴度为3.25×1010pfu/ml;通过建立SW-1990胰腺癌细胞Balb/c裸鼠皮下移植瘤模型,分析基因转导后胰腺癌组织中内皮抑素的表达情况及对肿瘤血管的抑制作用.结果 构建了AdTPHre-hEndo;AdTPHre-hEndo组荷瘤裸鼠肿瘤体积显著低于携带人内皮抑素基因的重组腺病毒(Ad-hEndo)组(P＜0.01)和选择性增殖型腺病毒(ONYX-015)组(P＜0.05);AdTPHre-hEndo组内皮抑素表达量明显高于Ad-hEndo组和对照组(P＜0.01).AdTPHre-hEndo组肿瘤微血管密度(MVD)为6.8±2.5,Ad-hEndo组和对照组MVD分别为16.0±4.6(P＜0.01)、47.2±10.0(P＜0.01).结论 所构建的AdTPHre-hEndo可有效表达具有生物学活性的内皮抑素,使肿瘤内微血管生成减少,肿瘤细胞增殖减慢,具备应用于胰腺癌临床治疗的潜力.     

重组腺病毒携带人血管抑素基因抑制胰腺癌血管生成的研究

目的研究重组腺病毒介导的人血管抑素基因(Ad-hAG)对胰腺癌血管生成的抑制作用。方法通过病毒重组技术将人血管抑素K5基因克隆人增殖缺陷型腺病毒基因组中,获得腺病毒滴度达5.5×10~(10)pfu/ml。转染人胰腺癌细胞,Western印迹和ELISA法检测人血管抑素基因的蛋白表达情况,并通过建立荷人胰腺癌的裸鼠动物模型(每组15例),微血管密度计数分析血管抑素对胰腺癌血管形成的影响。结果成功构建了携带血管抑素K5基因的腺病毒Ad-hAG;检测到重组腺病毒载体介导的血管抑素基因在胰腺癌细胞内高表达,微血管密度计数(MVD)治疗组为8.75±2.12,对照组MVD分别为20.52±1.25、18.52±1.36(t=6.165,P<0.05)。结论重组腺病毒介导的血管抑素基因在体内、外均获得高效表达,可明显抑制裸鼠胰腺癌血管形成和肿瘤生长。     

鼠源性血管抑素对裸鼠种植性肿瘤的抑制作用

目的　探讨鼠源性血管抑素转染入人肝癌细胞SMMC 772 1后对裸鼠种植性肿瘤的影响。　方法　建立鼠源性血管抑素基因的人肝癌SMMC 772 1细胞株 ,实验动物分 3组 :空白对照组种植SMMC 772 1细胞 ,空载体组种植SMMC 772 1/pcDNA3 1(+)细胞 ,血管抑素组种植SMMC 772 1/pcDNA3 1 mAST细胞。比较各组裸鼠肿瘤体积、重量和肿瘤微血管密度 (MVD)。　结果　在肿瘤细胞种植 35d时裸鼠肿瘤体积 :空白对照组 (35 38 1± 6 43 3)mm3 ,空载体组 (312 8 5± 5 46 6 )mm3 ,血管抑素组 (75 5 8± 198 2 )mm3 ;肿瘤重量 :空白对照组 (6 0± 0 7)g,空载体组 (5 9± 0 5 )g ,血管抑素组(2 1± 0 5 )g;肿瘤MVD :空白对照组 5 2 2± 6 6 ,空载体组 49 4± 7 0 ,血管抑素组 2 5 5± 4 1。血管抑素组裸鼠肿瘤体积、重量和MVD显著小于空白对照组和空载体组 (P均 <0 0 1) ,肿瘤的抑制率达78 6 %。　结论　转染血管抑素基因的人肝癌细胞SMMC 772 1在裸鼠体内的致瘤力明显降低 ,肿瘤的体积、重量和微血管密度显著低于对照组 ,表明血管抑素可通过抑制肿瘤血管生成而显著抑制肿瘤生长     

内皮抑素转基因治疗裸鼠人肝癌的实验研究

目的构建表达人内皮抑素的重组真核表达载体,研究阳离子脂质体介导转染内皮抑素基因对裸鼠人肝癌生长的抑制作用。方法将含有IL-2信号肽和人内皮抑素基因全长cDNA插入真核表达载体pcDNA3.0产生重组质粒pCD-sEndo,脂质体Dosper介导将pCD-sEndo质粒转染至人肝癌细胞株SMMC-7721,RT-PCR和Western blot检测内皮抑素的表达。建立裸鼠人肝癌模型,按随机数字表法随机分成4组,分别瘤内注射Dosper+pCD-sEndo(Dosper+pCD-sEndo组)、Dosper+pcDNA3.0(Dosper+pcDNA3.0组)、Dosper(Dosper组)和生理盐水(生理盐水组),分时段测量肿瘤的体积;注射结束后1周处死动物,切取肿瘤,免疫组化检测肿瘤组织微血管密度(MVD),TUNEL染色检测肿瘤细胞凋亡指数(AI)。结果成功构建携带人内皮抑素基因和IL-2信号肽的真核表达质粒pCD-sEndo并经酶切鉴定证实;体外转染内皮抑素基因的SMMC-7721细胞,RT-PCR可以检测到内皮抑素mRNA表达,Western blot显示转染细胞培养液中有内皮抑素蛋白表达,而转染空白质粒者中没有;体内实验中,Dosper+pCD-sEndo组裸鼠肿瘤生长受抑,于第12 d起明显小于Dosper+pcDNA3.0组、Dosper组和生理盐水组(P<0.05)。Dosper+pCD-sEndo组平均MVD为6.2±2.5,明显低于生理盐水组(32.8±6.4)、Dosper组(27.8±6.4)和Dosper+pcDNA3.0组(25.5±5.5),P<0.05;Dosper+pCD-sEndo组肿瘤细胞平均AI为24.5±7.3,生理盐水组、Dosper组和Dosper+pcDNA3.0组分别是7.6±2.5、9.5±3.0和11.2±3.6,前者明显高于后三者(P<0.05)。结论瘤内注射携带内皮抑素基因的阳离子脂质体,可减少裸鼠体内种植性人肝癌的微血管数目,促进肿瘤细胞凋亡,抑制肿瘤生长。     

新型血管生成抑制人内皮细胞抑制素-血管内皮细胞生长抑制因子151治疗胃癌的实验研究

目的研究重组腺病毒表达的人内皮细胞抑制素-血管内皮细胞生长抑制因子151(hENDO-VEGI151)融合蛋白对胃癌的抑制作用.方法构建携带hENDO-VEGI151融合基因的重组腺病毒载体,脂质体介导法包装重组腺病毒Ad IL-3/hENDO-VEGI151.体外检测融合基因的表达及融合蛋白的生物学活性.应用鸡胚绒毛尿囊膜(CAM)模型及荷人胃癌裸鼠模型,进一步观察融合蛋白对活体血管生成的影响和融合基因治疗活体胃癌的疗效.结果用TCID50法测定携带融合基因的重组腺病毒滴度为4.2×1011TCID50/ml;用聚合酶链反应(PCR)、逆转录(RT)-PCR和免疫组织化学方法证实融合基因可被转导入SGC-7901细胞内并稳定高效地转录和表达;Western blot显示融合蛋白可被分泌到胞外发挥作用;融合蛋白可强烈抑制ECV-304细胞生长及鸡胚绒毛尿囊膜新生血管形成.Ad IL-3/hENDO-VEGI151治疗可强烈抑制裸鼠体内种植瘤生长,明显下调肿瘤微血管密度,促进胃癌细胞凋亡.结论 hENDO-VEGI151是一条新型强效的肿瘤血管生成抑制基因,其表达产物可能通过作用于肿瘤新生血管形成的不同环节强烈抑制新血管生成和肿瘤生长,值得进一步研究.     

重组腺相关病毒介导caveolin-1基因表达抑制肝癌新生血管形成的实验研究

目的 探讨caveolin-1参与肝细胞癌血管生成及影响血管通透性的作用机制.方法 构建肝癌细胞系HepG2裸鼠皮下移植瘤模型,局部注射编码重组可溶性caveolin-1蛋白的重组腺相关病毒载体rAAV-PEG-caveolin-1,观察其对肝癌细胞生长的抑制作用;通过肿瘤微血管密度(microvessel density,MVD)检测肿瘤新生血管的生成;Western blot检测脉管标志蛋白PECAM-1表达改变;FITC标记右旋糖苷测定肿瘤微血管通透性;放射强度测定法检测肝癌组织中eNOS活性,TUNEL法检测caveolin-1对肿瘤细胞的诱导凋亡效应.结果 rAAV-PEG-caveolin-1转染组治疗第14天后,移植瘤的瘤重较对照组和空载体转染组有不同程度的减小(P＜O.05);免疫组化分析及Western blot结果显示rAAV-PEG-caveolin-1转染组较对照组及空载体组MVD及PECAM-1表达显著减少(P＜0.05);FITC-右旋糖苷测定表明rAAV-PEG-caveolin-1可有效降低肿瘤微血管通透性;rAAV-PEG-caveolin-1转染组较对照组及空载体组eNOS活性明显下降(P＜0.05);TUNEL分析显示rAAV-PEG-caveolin-1可诱导肿瘤细胞凋亡.结论 Caveolin-1是血管生成调节的关键分子,能显著抑制肿瘤新生血管的形成,并能有效降低肿瘤微血管的通透性.     

胰腺癌的血管生成及临床意义

目的　探讨人胰腺癌的微血管数量与肿瘤生物学特性的关系。方法　用免疫组织化学染色标记微血管内皮细胞 ,回顾性定量研究 5 5例人胰腺癌组织中微血管密度 (MVD ) ,并与临床病理学资料和随访资料作对比分析。结果　胰腺癌组织中平均微血管数量为 5 4.8± 18.6,癌旁组织中为11.2± 4.8,MVD与肿瘤细胞的分化程度、TNM分期、淋巴结转移有关 ,低血管组比高血管组术后生存时间明显延长。结论　胰腺癌的血管生成能反映肿瘤的恶性程度 ,MVD可作为胰腺癌分化、浸润、转移与预后分析的指标。     

环氧合酶2对胰腺癌新生血管生成的调节作用及其机制

目的　探讨环氧合酶 2 (COX 2 )在胰腺癌新生血管生成中的调节作用及其作用机制。方法　应用免疫组织化学染色研究人胰腺癌组织COX 2、血管内皮细胞生长因子 (VEGF)表达 ;同时标记肿瘤新生血管内皮细胞vWF和血管壁Ⅳ型胶原 ,计算肿瘤组织微血管密度 (MVD)。建立裸鼠胰腺癌细胞株PC 3移植瘤 ,观察选择性COX 2抑制剂Celebrex对肿瘤组织MVD的影响 ,并应用免疫组织化学染色和逆转录聚合酶链式反应 (RT PCR)研究裸鼠移植瘤组织VEGF表达变化。结果　COX 2在人胰腺癌组织中表达阳性率为 87 5 % ,VEGF阳性率为 5 8 3%。COX 2强阳性组MVD平均值显著高于COX 2弱阳性 +阴性组 ,P <0 0 1。VEGF阳性组MVD平均值高于VEGF阴性组 ,但无统计学差异 ,P >0 0 5 ;Pearson相关性检验结果表明COX 2与vWF和Ⅳ胶原标记的MVD均有明显的相关性 (相关系数分别为 0 5 99和 0 6 ) ,P <0 0 5。在裸鼠移植瘤的体内实验中 ,与对照组MVD(6 3 89± 13 6 7)相比 ,Celebrex处理组MVD为 32 2 5± 12 99,两者差异显著 ,P <0 0 1。免疫组织化学染色和RT PCR结果表明Celebrex处理组肿瘤组织VEGF表达较对照组明显下调。结论　COX 2与胰腺癌新生血管生成密切相关 ,其高表达促进了胰腺癌新生血管生成 ;可能作用机制是上调促血管生成因子VEGF     

血管内皮生长因子反义核酸对胰腺癌细胞增殖、凋亡和血管生成的影响

目的探讨腺病毒介导的血管内皮生长因子(VEGF)反义核酸对胰腺癌细胞增殖、凋亡和血管生成的作用。方法构建反向插入VEGF165基因的复制缺陷型腺病毒载体(Ad-αVEGF)。18只裸鼠皮下接种人胰腺癌细胞株SW1990,随机分成3组(n=3),1周后瘤体内分别注射磷酸盐缓冲液(PBS,100μl,PBS对照组)、报告基因LacZ重组腺病毒(100μl,Ad-LacZ对照组)、反义VEGF重组腺病毒(100μl,Ad-αVEGF治疗组),隔日1次,共4次。1个月后处死动物。PCNA染色、TUNEL法和CD31染色观察反义VEGF165基因转染对胰腺癌细胞增殖、凋亡和血管生成的影响。结果Ad-αVEGF治疗组PCNA阳性表达率为(38.1±6.8)%,较LacZ组(89.6±4.3)%、PBS对照组(92.1±5.2)%明显降低(P<0.01),LacZ组与PBS对照组之间差异无统计学意义(P>0.05)。Ad-αVEGF治疗组细胞凋亡率(32.3±3.8)%,明显多于LacZ组(8.6±7.6)%和PBS对照组(9.9±4.2)%(P<0.01),LacZ组与PBS对照组之间差异无统计学意义(P>0.05)。Ad-αVEGF治疗组肿瘤微血管密度(12±3),明显少于LacZ组(26±5)和PBS对照组(25±4)(P<0.01),LacZ组与PBS对照组之间差异无统计学意义(P>0.05)。结论反义VEGF165基因转染可以抑制肿瘤细胞增殖,增加细胞凋亡,减少了肿瘤内微血管数量,从而抑制肿瘤生长。     

重组腺相关病毒介导caveolin-1基因表达抑制肝癌新生血管形成的实验研究

目的 探讨caveolin-1参与肝细胞癌血管生成及影响血管通透性的作用机制.方法 构建肝癌细胞系HepG2裸鼠皮下移植瘤模型,局部注射编码重组可溶性caveolin-1蛋白的重组腺相关病毒载体rAAV-PEG-caveolin-1,观察其对肝癌细胞生长的抑制作用;通过肿瘤微血管密度(microvessel density,MVD)检测肿瘤新生血管的生成;Western blot检测脉管标志蛋白PECAM-1表达改变;FITC标记右旋糖苷测定肿瘤微血管通透性;放射强度测定法检测肝癌组织中eNOS活性,TUNEL法检测caveolin-1对肿瘤细胞的诱导凋亡效应.结果 rAAV-PEG-caveolin-1转染组治疗第14天后,移植瘤的瘤重较对照组和空载体转染组有不同程度的减小(P＜O.05);免疫组化分析及Western blot结果显示rAAV-PEG-caveolin-1转染组较对照组及空载体组MVD及PECAM-1表达显著减少(P＜0.05);FITC-右旋糖苷测定表明rAAV-PEG-caveolin-1可有效降低肿瘤微血管通透性;rAAV-PEG-caveolin-1转染组较对照组及空载体组eNOS活性明显下降(P＜0.05);TUNEL分析显示rAAV-PEG-caveolin-1可诱导肿瘤细胞凋亡.结论 Caveolin-1是血管生成调节的关键分子,能显著抑制肿瘤新生血管的形成,并能有效降低肿瘤微血管的通透性.     

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 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.     

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.