进展期胃癌D2根治术中第14v组淋巴结清扫的意义

目的探讨进展期胃癌行D：根治术时第14v组淋巴结清扫的必要性。方法回顾性分析2003至2007年间天津医科大学附属肿瘤医院收治的131例行胃癌根治术（D2或D2＋）并同时加行第14v组淋巴结清扫的胃癌患者的临床病理资料，分析影响第14v组淋巴结转移的临床病理因素以及第14v组淋巴结转移与预后的关系。结果131例患者中24例（18．3％）有第14v组淋巴结转移。原发灶部位、肿瘤大小、浸润深度、淋巴结分期、TNM分期、第1、6、8a组淋巴结转移与第14v组淋巴结转移有关（均P〈0．05）；其中原发灶部位和淋巴结分期是影响第14v组淋巴结转移的独立因素（均P〈0．05）。第14v组淋巴结转移和未转移患者5年生存率分别为8．3％和37．8％，差异有统计学意义（P〈0．01）。多因素预后分析证实。第14v组淋巴结转移是影响进展期胃癌D：根治术后生存的独立危险因素（P=-0．029，RR=1．807，95％CI：1．064-3．070）。结论对于进展期胃中下部癌．尤其是肿瘤体积较大、浆膜受侵犯、第6组淋巴结可疑转移的患者，第14v组淋巴结清扫是必要可行的。     

进展期胃下部癌第12p组淋巴结转移的相关因素分析北大核心CSCD

目前D2根治术被认为是进展期胃癌的标准术式,但是对胃下部癌手术中是否需要清扫第12p组淋巴结仍未达成共识[1].本研究回顾性分析进展期胃下部癌第12p组淋巴结转移的相关因素,探讨胃下部癌D2根治术清扫第12p组淋巴结的必要性.     

胃下部癌常规病理阴性第11P组淋巴结微转移的研究

目的 检测胃下部癌患者常规病理阴性第11P组淋巴结微转移的情况,分析淋巴结微转移与临床病理因素的关系.方法 应用连续切片法和端粒酶重复扩增-ELISA方法 检测43例胃下部癌常规病理阴性的43枚第11P组淋巴结,结合临床病理资料进行统计学分析. 结果 本组43例胃下部癌患者常规病理阴性第11P组淋巴结经连续切片法检出有4例4枚淋巴结发生微转移,微转移发生率为9%;应用端粒酶重复扩增-ELISA法检测微转移发生率为44%,其中包括应用连续切片法检测出有微转移的4枚淋巴结.端粒酶重复扩增-ELISA法微转移检出率明显高于连续切片法(x 2 =13.07,P<0.05).胃下部癌第11P组淋巴结微转移与原发肿瘤大小(x 2 =8.488,P<0.05)、浸润深度(x 2 =6.473,P<0.05)及临床分期(x 2 =12.022,P<0.05)有关,与患者年龄、性别、大体分型、组织分化程度尤关.结论 胃下部癌常规病理阴性第11P组淋巴结中存在较高的微转移发生率,其微转移发生率与原发肿瘤大小、浸润深度及临床分期有关.     

胃癌胰头后淋巴结清扫术指征的探讨

目的 分析胃癌患者胰头后淋巴结(第13组)微转移率及转移规律,探讨第13组淋巴结清扫术的指征.方法 通过实时定量免疫荧光PCR法(RQ-PCR)检测研究组44例行D2胃癌根治术+胰头后淋巴结清扫术的胃癌患者术中切除的第13组淋巴结中胃癌特异性标志物CK20 mRNA的表达情况,另选取49例同期行标准D2胃癌根治术的患者作为对照组,对比分析两组患者的生存情况.结果 研究组44例中共有11例发生第13组淋巴结微转移,微转移率为25%.微转移与患者年龄、性别、原发肿瘤部位、原发癌灶大小、Bormann分型、肿瘤浸润深度无关(P>0.05),但与原发肿瘤病理类型相关(P<0.01),黏液细胞癌、印戒细胞癌患者容易出现第13组淋巴结转移.6例肝十二指肠韧带淋巴结(第12组)和11例肠系膜上血管旁淋巴结(第14组)转移的患者中分别有2例(F=23.694,P<0.01)和4例(F=13.756,P<0.01)出现第13组淋巴结转移,与其他各组淋巴结相比差异有统计学意义.两组的中位随访时间分别为448 d和419 d,研究组中无1例出现术后第13组淋巴结转移所造成的梗阻性黄疸,对照组中发现1例,但两组患者肿瘤复发率之间相比差异无统计学意义(x2=0.426,P=0.514).结论 对于黏液细胞癌、印戒细胞癌患者,或术中发现第12组或第14组淋巴结肿大的患者,应该在标准D2根治术的基础上施行胰头后淋巴结清扫术.     

两种手术方案治疗进展期胃中上部癌的临床对比研究

目的:探讨D2淋巴结清扫术与全系膜切除术治疗进展期胃中上部癌的临床疗效及安全性。方法:选取2011年5月至2014年1月收治的100例进展期胃中上部癌患者,分为对照组(n=50)与观察组(n=50),分别采用D2淋巴结清扫术与全系膜切除术,比较两组患者手术相关临床指标、术后并发症发生率、随访复发率及生存率。结果:观察组手术时间、术中出血量均优于对照组(P0.05),两组淋巴结清扫数量、首次排气时间、首次下床活动时间、住院时间、术后并发症发生率及随访复发率差异无统计学意义(P0.05),观察组随访生存率高于对照组(P0.05)。结论:全系膜切除术治疗进展期胃中上部癌可有效缩短手术时间,减少医源性创伤,并有助于提高远期生存率,优于D2淋巴结清扫术。     

不同病理类型进展期胃癌的预后因素分析

目的探讨不同病理类型进展期胃癌患者的临床病理特征及预后因素。方法回顾性分析2011年间在南京大学医学院附属鼓楼医院集团宿迁市人民医院行胃癌根治术的98例进展期胃癌患者的临床病理资料,其中胃腺癌53例,胃黏液腺癌30例,胃印戒细胞癌15例,比较不同病理类型进展期胃癌患者的临床病理特征及预后的差异。结果 (1)3种不同病理类型进展期胃癌患者的性别、年龄、神经侵犯及分化程度比较差异无统计学意义(P0.05),而其肿瘤直径、肿瘤位置、手术根治类型、区域淋巴结转移、淋巴管癌栓、侵犯深度及p TNM分期比较差异有统计学意义(P0.05)。(2)单因素分析结果显示,胃腺癌患者的预后与肿瘤直径、肿瘤位置、手术根治类型、区域淋巴结转移、侵犯深度及p TNM分期有关(P0.05),胃黏液腺癌患者的预后与手术根治类型、区域淋巴结转移及p TNM分期有关(P0.05),胃印戒细胞癌患者的预后与区域淋巴结转移、侵犯深度及p TNM分期有关(P0.05)。(3)将与3种不同病理类型进展期胃癌患者预后有关的因素进一步行Cox多因素分析,结果显示,肿瘤位置(P=0.016)、区域淋巴结转移(P=0.042)、侵犯深度(P=0.021)及p TNM分期(P=0.009)是影响胃腺癌患者预后的独立危险因素,区域淋巴结转移是影响胃黏液腺癌患者预后的独立危险因素(P=0.000),肿瘤侵犯深度(P=0.032)及区域淋巴结转移(P=0.002)是影响胃印戒细胞癌患者预后的独立危险因素。(4)随访时间60个月,胃腺癌患者的中位随访时间为32个月,胃黏液腺癌患者为43个月,胃印戒细胞癌患者为23个月,5年累积生存率胃腺癌患者为30.2%,胃黏液腺癌患者为23.3%,胃印戒细胞癌患者为26.7%。三者生存曲线比较差异无统计学(P=0.131)。结论不同病理类型进展期胃癌患者的临床病理特征有一定的差异,从而影响其预后的因素也不同,但是区域淋巴结转移是影响3种不同病理类型进展期胃癌患者的共同预后因素。     

进展期胃癌淋巴结清扫及胃切除范围 进展期胃下部癌淋巴结清扫及胃切除范围

张一楚教授 :胃下部癌指幽门窦部癌(Ｌ) ,有时涉及胃中部 (Ｍ )和十二指肠(Ｄ)即Ｌ ,ＬＭ ,ＬＤ区域。进展期胃癌Ⅱ期 :其肿癌可侵及浆膜层Ｔ3,淋巴结转移达Ｎ2 ,将转移淋巴结个数与转移距离结合考虑 ,系指 3ｃｍ外的淋巴结有转移或区域性淋巴结转移数为 7～ 15个 ,按区域性淋巴结的解剖位置为第二站淋巴结转移 ,此期包括Ｔ1Ｎ2 Ｍ0 ,Ｔ2 Ｎ1Ｍ0 ,Ｔ3Ｎ0 Ｍ0 。进展期胃癌Ⅲａ期 ,肿瘤可侵及邻近器官或腔内扩展至十二指肠均为Ｔ4 ,淋巴结转移达Ｎ2 ,此期包括Ｔ2 Ｎ2 Ｍ0 ,Ｔ3Ｎ1Ｍ0 ,Ｔ4 Ｎ0 Ｍ0 。1　淋巴结清扫范围淋巴结清扫范围与肿瘤所…     

进展期胃癌以术中淋巴显影为指导的D2根治术

目的 比较进展期胃癌在D2基础上以术中淋巴显影为指导的个体化清扫与常规D2根治术的淋巴结清扫效果.方法 20例进展期胃癌患者术中在肿瘤周围注射纳米炭混悬液者为纳米炭组,在D2根治术的基础上以黑染淋巴结为指导进行个体化清扫.21例常规行D2根治术的进展期胃癌为对照组,比较两组清扫淋巴结的数目及淋巴结转移情况、纳米炭组淋巴结黑染情况,并观察其副作用及并发症.结果 纳米炭组平均清扫淋巴结(35.1±13.4)枚/例,高于对照组的(26.2±7.8)枚/例,两者相比差异有统计学意义(t=2.126,P=0.034),主要体现在N2、N3淋巴结的清扫;纳米炭组淋巴结黑染率为52.7%,黑染淋巴结中发生转移的阳性率(27.6%)高于未黑染淋巴结(10.8%)及对照组(16.9%),差异均有统计学意义(x2=6.034,P=0.016;x2=5.142,P=0.023);纳米炭组术后1例发生输入襻梗阻.结论 在D2根治术的基础上以术中淋巴显影技术为指导对进展期胃癌进行淋巴结清扫,能增加淋巴结清扫的效率.     

Siewert Ⅱ型和Ⅲ型食管胃结合部腺癌淋巴结转移规律及预后分析

目的 探讨Siewert Ⅱ型和Ⅲ型食管胃结合部腺癌淋巴结转移规律及预后分析.方法 选取2013年7月-2017年3月在首都医科大学附属北京友谊医院普外科接受根治性手术并具有完整临床资料的Siewert Ⅱ型和Ⅲ型食管胃结合部腺癌患者65例,主要研究指标为性别、年龄、肿瘤部位、肿瘤大小、大体类型、组织学类型、浸润深度、手术方式、脉管内癌栓、癌结节;采用Logistic回归模型分析淋巴结转移危险因素,Kaplan-Meier法进行生存分析.出院后通过门诊、电话等方式随访,随访截至2017年4月.结果 所有患者淋巴结转移率为63.1％(41/65),各组淋巴结转移中,以第1、2、3、7、11和110组淋巴结转移频次最高,转移率分别为45.3％、32.5％、28.8％、22.5％、19.4％和8.2％;肿瘤最大径＜2 cm淋巴结转移率为0,肿瘤最大径≥2 cm淋巴结转移率为71.9％(P=0.000);早期癌(T1)和进展期癌(T2 ～T4)淋巴结转移率分别为0、12.5％、69.0％和95.2％(P=0.000);分化型淋巴结转移率为45.2％,低于未分化型淋巴结转移率79.4％ (P =0.009);33例患者合并脉管内瘤栓,其中28例(84.8％)伴有淋巴结转移(P=0.001);多因素分析显示,组织学类型及脉管瘤栓是影响Siewert Ⅱ型和Ⅲ型食管胃结合部腺癌淋巴结转移的独立危险因素.65例患者均获得随访,术后随访1 ～45个月,平均18.81个月.生存分析显示,无淋巴结转移者3年总体生存率较合并淋巴结转移者差异无统计学意义(P=0.167),但较合并淋巴结转移者存在生存优势;肿瘤分期对于3年总体生存率差异无统计学意义(P =0.429),但早期肿瘤较进展期肿瘤具有生存优势.结论 Siewert Ⅱ型和Ⅲ型食管胃结合部腺癌淋巴结转移主要与组织学类型及脉管内瘤栓相关;其中第1、2、3、7、11和110组淋巴结转移率高,因而建议行根治性全胃切除术、D2淋巴结清扫术及常规清扫第110组淋巴结或清扫纵隔及食管裂孔周围淋巴结,对于合并淋巴结转移及肿瘤分期晚者,远期预后仍有待进一步研究证实.     

十二指肠乳头癌淋巴结转移特点与手术预后的关系

目的 探索十二指肠乳头癌(CPV)区域淋巴结转移特点与预后的关系,以指导CPV根治术中淋巴结的清扫.方法 回顾性分析东方肝胆外科医院2005年1月至2010年12月间94例行根治性胰十二指肠切除CPV区域淋巴结转移特点,分析与其预后相关的临床病理因素.结果 本组淋巴结转移率为46.8％,其中pT1、pT2、pT3和pT4期淋巴结转移率分别为15.4％(2/13)、62.7％(32/51)、80.0％(8/10)和100％(2/2).94例区域淋巴结中,胰十二指肠后组、胰腺钩突系膜组、肝十二指肠韧带组及肝固有动脉旁组淋巴结转移率依次为30.9％、21.3％、11.7％和6.4％.预后相关因素:肿瘤pT分期(P＜0.01)、十二指肠壁浸润(P=0.001)、肝转移(P=0.001)、胰腺浸润(P=0.004)、淋巴结转移(P＜0.01);各区域淋巴结转移:胰十二指肠后组淋巴结(P＜0.01)、胰腺钩突系膜组淋巴结(P＜0.01)、肝十二指肠韧带组淋巴结(P＜0.01)、肝固有动脉旁组淋巴结(P=0.010);预后独立危险因素:胰十二指肠后组淋巴结转移(P＜0.01)、胰腺钩突系膜组淋巴结转移(P＜0.01)、十二指肠壁浸润(P=0.019).结论 钩突系膜组淋巴结和胰十二指肠后组淋巴结均是CPV转移的第一站,均可独立影响CPV术后生存率.术中应重视该区域淋巴结的清扫,特别是保证完整切除胰腺钩突及系膜组织.     

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.     

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.