胎猪脱细胞主动脉作为小口径组织工程血管替代物的体内试验研究

目的:研究胎猪脱细胞主动脉(decellularized aorta of fetal pigs,DAFP)的生物相容性,确定其是否有作为支架材料用于小口径组织工程血管移植的潜力。方法:利用胰酶和核酸酶联合的脱细胞方法来制备胎猪主动脉脱细胞基质(DAFP),将其作为小口径组织工程血管的生物支架材料移植在成年犬单侧颈总动脉处,并监测其移植处的血流通畅情况,后期又通过组织学染色观察组织工程血管的组织学结构;扫描电镜观察血管的内表面结构;透射电镜观察其内表面的内皮细胞再生情况。结果:组织学染色结果表明构建的小口径组织工程血管具有完整的内膜层及中膜层结构;扫描电镜结果显示组织工程血管内表面覆盖着完整的内皮细胞层。结论:DAFP有作为小直径组织工程血管支架用于体内移植的潜力。     

犬内皮细胞化动脉支架的建立及体外测试

目的建立犬血管内皮细胞支架的制作方法,并在体外初步检测其治疗的可行性。方法取犬颈静脉分离培养出血管内皮细胞,并进行体外鉴定。将血管内皮细胞贴附于含有肝素的高分子材料涂层的不锈钢支架表面,形成内皮化支架。采用体外模拟血流冲刷试验观察0～24 h冲刷后的细胞形态,并计每1 mm长度支架表面的黏附细胞数以检测其黏附能力。结果培养获得犬血管内皮细胞。形成具有完整细胞层的内皮化支架。体外冲刷0、12、24 h细胞计数为305.30±22.54、294.70±20.45、288.60±30.97,差异无统计学意义(P<0.05)。结论犬血管内皮细胞可牢固贴附于含有肝素的药物高分子材料涂层的不锈钢支架表面,形成具有一定抗血流冲刷能力的内皮化细胞支架。     

血管化组织工程肝小块构建的研究

目的 利用组织工程方法和原理初步构建血管化肝小块组织。方法 肝细胞和肝窦内皮细胞取自小鼠肝脏。采用内管网高分子聚酯类聚合物（PLGA）材料作为支架。肝窦内皮细胞接种在内管网PLGA支架管道的内壁使之在体外预内皮化。肝细胞与纤维蛋白原混合制成肝细胞／纤维蛋白原混合液，接种在喷洒有凝血酶的预内皮化的内管网支架上。构建的复合物分别植于小鼠肠系膜部位（A组）和肝组织表面（B组）．2周后将支架取出观察，比较不同部位的植入效果。结果 支架体外预血管化后，其管道内可见内皮细胞均匀贴壁；体内植入后内皮细胞优势生长；A组小鼠肠系膜间支架中有血管长入，但未见有肝细胞留存；B组可见支架内有少量肝细胞团，并有血管长入。结论 简易PLGA内管网多孔支架可以用于肝组织小块的构建．而肝组织表面更适合组织工程肝小块的体内植入。     

粉末冶金注射成型技术制备的新型血管内支架的动物应用研究

目的:通过动物实验评估一种新型血管内支架临床应用的可行性和安全性。方法:将30枚粉末冶金注射成型技术制备新型血管内支架分别植入30只实验犬主动脉内,术后CT血管造影了解其在主动脉内情况,并通过大体肉眼观察、光镜、电镜及免疫组化了解内术后不同时间支架表面新生内膜情况。结果:所有支架均成功植入实验犬主动脉内。术后支架通畅率100%,无支架移位、扭曲、断裂,无支架感染及血栓形成,管腔无狭窄或闭塞;支架的轴向回缩率均2%,径向回缩率均4%。术后1周,支架腔面迅速被一薄层半透明膜状结构覆盖;术后1个月,支架绝大部分表面可见与周围血管正常内膜相延续的新生内膜;术后2个月,新生内膜基本上完整覆盖整个支架腔面(98.83%),其厚度达到峰值(350.00μm);术后3~6个月,新生内膜厚度逐渐降低,管腔内径逐渐增大至植入前大小,最后新生内膜表面被单层完全成熟的内皮细胞覆盖。除术后1周外,其余时间点支架表面新生内膜组织中血管平滑肌细胞α-肌动蛋白染色均呈阳性,而各时间点支架腔面新生内膜组织中血管内皮生长因子染色均呈阳性。结论:粉末冶金注射成型技术制备的新型血管内支架植入后实验犬体内后形态结构稳定,并可迅速完成支架腔面内皮化,保持长期的通畅性,表现出良好的结构及理化稳定性和生物相容性,具有很好的临床应用前景。     

体外组织工程血管支架内皮化的实验研究

目的：研究兔血管内皮细胞种植于组织工程血管支架内腔面的生长状况。方法：（1）将聚羟基乙酸（Plyglycolic acid,PGA)纤维无纺网和胶原纤维相混合，设计构建组织工程血管支架材料。（2）采用酶消化法从兔主动脉中分离培养兔血管内皮细胞并传代，纯化，接种于组织工程血管支架的内腔面，体外培养，并行电镜等观察。结果：该支架具有一定弹性和韧性，内皮细胞在其内表面形成较完整内皮细胞层，生长状况良好。结论：胶原包埋处理的PGA支架可以作为组织工程人工血管研究的较理想支架材料。为组织工程方法构筑具有分层结构的组织工程血管打下实验基础。     

颈动脉支架植入后支架表面新生内膜增生与斑块内新生血管的关系探讨

目的探讨颈动脉支架植入术(carotid artery stenting,CAS)后支架表面新生内膜增生与斑块内新生血管的关系。方法纳入西安交通大学第一附属医院2014～2016年接受CAS治疗的67例患者,使用超声造影评估术后1年内颈动脉斑块内新生血管及支架表面新生内膜增生情况。结果 10例患者在支架植入后1年内出现支架表面新生内膜增生。CAS术后第6、12个月,新生内膜组斑块内新生血管G2级所占百分比显著高于非新生内膜组(P分别=0.002和0.001)。CAS后支架内新生内膜增生与斑块内新生血管呈显著的正相关关系(r=0.425,P0.001)。结论颈动脉支架植入后支架表面新生内膜增生与斑块内新生血管丰富程度有关,监测斑块内新生血管可能预测新生内膜增生。     

脱细胞牛颈静脉血管支架的内皮化研究

目的 探讨在脱细胞牛颈静脉血管支架上进行内皮细胞再种植的可行性.方法 将人骨髓间充质干细胞(BMDCs)诱导分化为内皮种子细胞后种植在脱细胞牛颈静脉血管支架上,分为动态培养和静态培养2组.培养7 d后,对标本进行病理和扫描电镜观察.结果 静态培养的血管支架表面形成连续的单细胞层.动态培养后血管支架表面的细胞仍有50%残留,沿流场方向排列.结论 人骨髓间充质干细胞诱导分化的内皮种子细胞在脱细胞牛颈静脉血管支架上可以黏附生长.     

急性肺损伤患者血清C5a对肺血管内皮细胞依赖性粘附的影响

目的 探讨急性肺损伤(ALI)早期肺血管内皮细胞损伤的机制及介导血管内皮细胞依赖性粘附的分子基础。方法 夹心酶联免疫吸附(ELISA)法测定和比较正常人及ALI后患者血清中C5a的含量；用流式细胞术(FCM)检测ALI患者血清刺激人肺血管内皮细胞，观测其表面粘附分子：P选择素和细胞间粘附分子(ICAM)—1的表达变化，同时通过检测粘附子血管内皮细胞表面的中性粒细胞(PMN)中髓过氧化物酶(MPO)活性，间接反映血管内皮细胞表面PMN的粘附和聚集。结果 ALI患者血清中C5a含量明显升高，同正常组比较差异有显著性；原代培养的肺血管内皮细胞，受ALI患者血清刺激后，其表面P—选择素的表达迅速增加，20min达到高峰，60min后开始降低，而ICAM—l的表达较慢，3h开始升高，12h达到最高值，24h内无明显下降，仍维持在较高水平；血管内皮细胞表面粘附的PMN中MPO的活性，3h明显升高，12h后达到最高值。结论 ALI患者血清中C5a含量明显升高，促进了PMN在肺微血管内的扣押、聚集进而同血管内皮细胞相粘附；而血管内皮细胞依赖性粘附的增强，主要是源血管内皮细胞上P—选择素和ICAM—l的表达增加，它们在ALI的发生、发展中起到重要作用。     

人工血管内支架与腹主动脉的生物相容性

目的评价人工血管内支架与腹主动脉的生物相容性。方法用膨体聚四氟乙烯膜压于镍钛合金支架制成人工血管内支架,将其植入实验猪肾下腹主动脉。2、4、12周取材,切片行苏木素伊红(HE)染色、胶原纤维和弹力纤维染色、血管平滑肌细胞α肌动蛋白免疫组织化学检查以及细胞原位凋亡检测,并行图像分析,对照实验组与正常腹主动脉内膜厚度、胶原纤维和弹力纤维相对含量、血管平滑肌细胞密度和凋亡比例。结果实验组2周时人工血管内支架表面有内皮细胞覆盖,与正常组相比,其各时间点内膜增生显著(P<0.01),弹力纤维和胶原纤维的形态和分布基本正常(P>0.05),2、4周时中膜内血管平滑肌细胞密度和凋亡比例显著高于正常组(P<0.01)。结论人工血管内支架与腹主动脉有着良好的生物相容性,但内膜增生较明显。     

组织工程组织血管化研究新进展

组织工程的血管化问题是制约组织工程产品的关键问题之一。根据血管发生中内皮细胞的来源不同，将血管发生分血管生成和血管再生两种形式，两种血管形成的方式都是一个动态、复杂的生理过程，通过生长因子和粘附物质来调节。对组织工程组织的血管化研究模型有体外和体内两种。体外实验可以检测支架与内皮细胞的粘附、增殖及迁移、材料的细胞毒、血管化效应和各种生长因子的调节作用，体内最简单实用的模型是用鸡胚茸毛尿囊膜模型，更高等的实验模型是在完整的动物体。组织工程组织血管化的策略有对支架材料的表面结构进行修饰、在材料内复合缓释的生长因子、内皮细胞与其它种子细胞联合培养、体内血管网包裹、血管束植入、血管模板以及体外在人造组织内构造微血管等，但目前的方法或多或少地存在一些问题，相信随着对血管化的机制和分子基础的了解的不断深入，以及各种技术手段的不断发展、完善，最终会找到比较理想的血管化方法。     

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.     

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.