不同临床病理因素对肝细胞癌患者血清蛋白质指纹图谱的影响

目的 分析不同临床病理因素对肝细胞癌患者血清蛋白质指纹图谱的影响。方法 收集112例肝细胞癌患者血清,采用弱阳离子交换蛋白质芯片为检测介质,经表面加强激光解吸电离-飞行时间-质谱测定得到蛋白质指纹图谱,分别以性别、甲胎蛋白、门静脉癌栓、肿瘤大小、肿瘤数目、肝硬化等病理特征分组,通过BioMarker Wizard Software比较各组间血清蛋白质组分的差异。结果 在质荷比为1100～30000范围内,112例肝细胞癌的血清蛋白指纹图谱中,共检测出100个有意义的蛋白峰。（1）比较肿瘤数目：单发与多发组（≥2）,16个蛋白峰差异有统计学意义（P〈0．01）。（2）比较肿瘤最大直径：〉3cm与≤3cm组,仅1个蛋白峰差异有统计学意义;〉5cm与≤5cm组,4个蛋白峰差异有统计学意义;〉10cm与≤10cm组,3个蛋白峰差异有统计学意义（P〈0．01）。（3）比较门静脉肉眼癌栓组与无门静脉癌栓组：16个蛋白峰差异有统计学意义;比较门静脉镜下癌栓组与无门静脉癌栓组：仅2个蛋白峰差异有统计学意义;比较门静脉肉眼癌栓组与门静脉镜下癌栓组：8个蛋白峰差异有统计学意义（P〈0．01）。（4）按性别、肝硬化和甲胎蛋白分组比较,血清蛋白指纹图谱没有明显差异。结论 门静脉癌栓、肿瘤数目、肿瘤大小是影响肝细胞癌患者血清蛋白质指纹图谱的重要因素,而性别、肝硬化、甲胎蛋白对血清蛋白质指纹图谱没有明显影响;门静脉肉眼癌栓对血清蛋白质指纹图谱影响明显大于镜下癌栓;肿瘤大小以5cm分界对血清蛋白质指纹图谱影响最大。     

肝癌门静脉癌栓相关小分子的比较蛋白质组学分析

目的 筛选肝细胞肝癌门静脉癌栓(PVTT)形成过程中起重要作用的低相对分子质量蛋白质标记物.方法 选取肝癌门静脉癌栓和肝癌无癌栓患者原发瘤组织各12例,利用16%SDS-PAGE和Tris-Tricine系统进行双向电泳,得到小相对分子质量蛋白表达图谱,经Image Master软件对比分析后,基质辅助激光解析飞行时间质谱(MALDI-TOF MS/MS)对差异点进行鉴定.免疫印迹法对鉴定蛋白进行初步验证.结果 无PVTT和PVTT的原发瘤组织间共检测到88个差异点,其中相对分子质量(MW)低于20×103的差异点有42个.与无PVTT组比较,PVTT组中有41个蛋白点表达上调(其中19个MW低于20×103),47个蛋白点表达下调(23个MW低于20×103).经质谱鉴定共发现钙结合蛋白S100A11,脂肪酸结合蛋白-1等11种胶内差异小分子蛋白质.免疫印迹验证结果证实S100A11在有或无PVTT的原发瘤组织中的确存在表达差异.结论 PVTT的原发瘤组织与无PVTT原发瘤组织中存在差异表达的低相对分子质量蛋白,推测肝癌侵袭转移性与多种差异蛋白相关,S100A11可能是其中一种.     

肝细胞癌门静脉癌栓形成的分子生物学机制研究

目的 探讨肝细胞癌（HCC）患者门静脉癌栓（PVTT）形成的分子生物学机制。方法 采用免疫组织化学，原位杂交等方法分别对HCC伴有和不伴有PVTT的组织标本252例进行相关指标的检测，分析多种基因在PVTT形成中的意义。标本分为：A组，未发现转移和PVTT的原发肝细胞癌组织，78例；B组，伴PVTT的原发肝细胞癌组织，50例；C组，PVTT，92例；D组，癌旁组织。32例。结果 内皮钙黏附蛋白（E-CD）的表达为癌旁组织（D组）＞伴PVTT的原发癌组织（B组）＞门静脉癌栓组织（C组）；尿激酶型纤溶酶原激活物（uPA）／其受体（uPAR）的表达规律为门静脉癌栓组织（C组）＞伴PVTT的原发癌组织（B组）＞无转移肝癌组织（A组）（P均＜0．01）；增殖细胞核抗原（PCNA）的表达为门静脉癌栓组织（C组）＞伴PVTT的原发癌组织（B组）＞无转移肝癌组织（A组）；血管内皮细胞生长因子（VEGF）表达为门静脉癌栓组织（C组）＞伴PVTT的原发癌组织（B组）＞无转移肝癌组织（A组）（P均＜0．01）。结论PVTT组织中VEGF、PCNA、uPA／uPAR高表达，E-CD低表达为共同参与肝细胞癌门静脉癌栓形成的分子生物学机制。     

转移与无转移肝细胞癌患者血清蛋白质指纹图谱的比较

目的比较转移与无转移肝细胞癌(HCC)患者的血清蛋白质指纹图谱,筛选与肝癌转移相关的蛋白质。方法术前收集84例HCC患者(有转移45例,无转移39例)和30例健康成人的血清,采用弱阳离子交换蛋白质芯片为检测介质,经表面加强激光解吸电离-飞行时间-质谱(SELDI-TOF-MS)测定,得到蛋白质指纹图谱并运BioMarkerWizard软件分析比较。结果在质荷比(m/z)1500~30000范围内,比较有转移HCC与健康成人的血清,检测出的146个蛋白质峰中,69个蛋白质峰差异有统计学意义(P<0.05),比较无转移HCC与健康成人的血清,60个蛋白质峰差异有统计学意义(P<0.05),差异蛋白质峰中57个为有转移与无转移HCC的共有蛋白峰;单独比较有转移与无转移HCC血清,检测出的146个蛋白质峰中仅有11个蛋白质峰差异有统计学意义(P<0.05)。结论有转移与无转移HCC患者血清蛋白质之间有差异,但远较其与健康成人血清之间差异小;血清蛋白质指纹图谱中的差异蛋白质可能与肿瘤的发生和转移有关。     

乙型肝炎病毒相关性肝细胞癌患者肝硬化组织与癌组织蛋白质组的差异

目的分析乙型肝炎病毒(HBV)相关性肝细胞癌患者肝硬化组织与癌组织蛋白质组之间的差异,鉴定其中的差异蛋白质点.方法应用双向聚丙烯酰胺凝胶电泳,对12例肝细胞癌患者的肝细胞癌组织与肝硬化组织的蛋白质进行差异分析,应用基质辅助激光解吸离子化飞行时间质谱仪对差异蛋白质点进行了鉴定.结果经肝细胞癌组织与癌周组织的差异对比分析,共发现有表达水平存在显著差异的35个蛋白质点,14个差异蛋白质点得到了初步鉴定,其中5个蛋白质既往文献中曾报道其与肝细胞癌变相关.结论HBV相关性肝细胞癌蛋白质组与肝硬化组织蛋白质组之间存在差异;本实验研究中初步鉴定的差异蛋白质,可能有助于HBV相关性肝细胞癌的癌变机制、肿瘤标记和治疗靶标的进一步研究.     

肝癌病人血清蛋白质指纹图谱检测及其临床意义

目的用表面增强激光解吸离子化飞行时间质谱（surface-enhanced laser desorption-ionization time-of-flight mass spectrometry，SELDI-TOF-MS）和蛋白质芯片检测肝细胞性肝癌（以下简称肝癌）病人血清蛋白质指纹图谱，初步探讨筛选肝癌相关的血清候选标志物。方法应用SELDI-TOF-MS蛋白质芯片技术检测25例未经治疗的肝癌病人、25例经介入治疗的肝癌病人和50例性别、年龄匹配的正常健康人血清，获得弱阳离子交换芯片（weak cationic exchanger）蛋白表达图谱。用BioMarker Wizard软件分析肝癌差异蛋白并初步建立诊断模型。结果应用弱阳离子交换芯片在未经治疗的肝癌病人、经介入治疗的肝癌病人和正常人血清中检测到不同质荷比处有7个差异蛋白质峰，其蛋白质含量差异有统计学意义（P〈0．05）。2个蛋白峰（7777．27Da、9250．00Da）组合构建的诊断模型，鉴别未经治疗的肝癌病人和正常人的敏感性为92％（23／25），特异性为92％（46／50）。分别对这7个蛋白质峰进行数据库搜索，得到7种与之分子量最为接近的蛋白质。结论应用SELDL-TOF-MS筛选肝癌病人血清特异性生物标志物的方法快速、有效，操作自动化，检测到的这7个差异蛋白质可能是肝癌病人血清特异性生物标志物，可能参与了肝癌的发生、发展过程。     

肝细胞性肝癌及门静脉癌栓差异表达蛋白质组分析及意义

目的 观察人肝细胞性肝癌(HCC)及门静脉癌栓(PVTT)组织蛋白质表达谱的改变,筛查在转移中起重要作用的关键蛋白质分子.方法 用双向凝胶电泳(2-DE)对3对HCC组织及PVTT组织的总蛋白质进行分离,两组间差异蛋白点用质谱和数据库搜索鉴定,并用组化和荧光定量聚合酶链反应(PCR)进一步验证.结果 鉴定出10个差异表达蛋白,包括Ki-67、MTH-SP75、NM23等.对在M组织中表达显著增高的Ki-67,应用组化和荧光定量PCR检测出两组间存在差异并且在HCC组织中Ki-67的表达与PVTT呈正相关.结论 HCC转移与多种蛋白有关,其中Ki-67高表达可能在肝癌转移中起重要作用.     

胃癌患者唾液蛋白质组学分析

目的 应用差异蛋白质组学方法筛选唾液中与胃癌相关的蛋白质分子.方法 采用双向凝胶电泳(2-DE)分离胃癌患者和正常人群唾液总蛋白,从中选取差异表达蛋白质点,通过基质辅助激光解吸电离飞行时间串联质谱(MALD I-TOF-TOF-MS)鉴定差异表达的蛋白质;Western blot 验证蛋白质组学分析的结果.结果 通过两组人群唾液的双向凝胶电泳图谱分析发现15个差异蛋白质斑点,质谱鉴定出9种蛋白质,在胃癌患者唾液中高表达的有3个,其余6个在胃癌患者唾液中低表达.Western blot对表达增高的蛋白鸟嘌呤核苷酸解离抑制因子2(RhoGDI2)进行检测,结果与蛋白质组学分析结果一致.结论 蛋白质组学研究是筛选胃癌患者唾液中特异性标记物的有效手段.     

胃癌患者唾液蛋白质组学分析

目的 应用差异蛋白质组学方法筛选唾液中与胃癌相关的蛋白质分子.方法 采用双向凝胶电泳(2-DE)分离胃癌患者和正常人群唾液总蛋白,从中选取差异表达蛋白质点,通过基质辅助激光解吸电离飞行时间串联质谱(MALD I-TOF-TOF-MS)鉴定差异表达的蛋白质;Western blot 验证蛋白质组学分析的结果.结果 通过两组人群唾液的双向凝胶电泳图谱分析发现15个差异蛋白质斑点,质谱鉴定出9种蛋白质,在胃癌患者唾液中高表达的有3个,其余6个在胃癌患者唾液中低表达.Western blot对表达增高的蛋白鸟嘌呤核苷酸解离抑制因子2(RhoGDI2)进行检测,结果与蛋白质组学分析结果一致.结论 蛋白质组学研究是筛选胃癌患者唾液中特异性标记物的有效手段.     

胃癌患者唾液蛋白质组学分析

目的 应用差异蛋白质组学方法筛选唾液中与胃癌相关的蛋白质分子.方法 采用双向凝胶电泳(2-DE)分离胃癌患者和正常人群唾液总蛋白,从中选取差异表达蛋白质点,通过基质辅助激光解吸电离飞行时间串联质谱(MALD I-TOF-TOF-MS)鉴定差异表达的蛋白质;Western blot 验证蛋白质组学分析的结果.结果 通过两组人群唾液的双向凝胶电泳图谱分析发现15个差异蛋白质斑点,质谱鉴定出9种蛋白质,在胃癌患者唾液中高表达的有3个,其余6个在胃癌患者唾液中低表达.Western blot对表达增高的蛋白鸟嘌呤核苷酸解离抑制因子2(RhoGDI2)进行检测,结果与蛋白质组学分析结果一致.结论 蛋白质组学研究是筛选胃癌患者唾液中特异性标记物的有效手段.     

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.