犬自体骨髓干细胞在缺血肢体中新生血管形成中的作用

目的:探讨犬自体骨髓干细胞在缺血组织的新生血管形成中的作用.方法:抽取犬骨髓,经免疫磁珠系统分离出CD 34细胞,体外扩增并向血管内皮细胞诱导分化;建立犬双下肢缺血动物模型,将诱导分化细胞移植入一侧缺血肢体中作为实验组,另一侧缺血肢体植入等体积的生理盐水作为自体对照组.移植后6周,检测缺血肢体中新生血管的形成.结果:细胞移植后6周,动脉造影显示实验组缺血肢体侧枝循环增加,明显多于对照组.微血管密度检测实验组为(14±2.3)个/高倍镜视野,明显高于对照组(6±2.1)个/高倍镜视野(P<0.05).激光共聚焦显微镜证实缺血肢体中移植的自体骨髓干细胞参与了新生血管形成.结论:自体骨髓干细胞移植可以促进缺血肢体组织中的新生血管形成.     

重组人肝细胞生长因子联合粒细胞集落刺激因子对血管新生的影响

有研究表明,重组人粒细胞集落刺激因子(rhG-CSF)和重组人肝细胞生长因子(rhG-HGF)均能诱导下肢缺血区域的血管生成[1].本实验旨在兔下肢缺血模型上观察rhG-CSF和rhG-HGF联合应用对缺血肢体侧枝血管新生的影响.     

重组人肝细胞生长因子联合粒细胞集落刺激因子对血管新生的影响

有研究表明,重组人粒细胞集落刺激因子(rhG-CSF)和重组人肝细胞生长因子(rhG-HGF)均能诱导下肢缺血区域的血管生成[1].本实验旨在兔下肢缺血模型上观察rhG-CSF和rhG-HGF联合应用对缺血肢体侧枝血管新生的影响.     

重组人肝细胞生长因子联合粒细胞集落刺激因子对血管新生的影响

有研究表明,重组人粒细胞集落刺激因子(rhG-CSF)和重组人肝细胞生长因子(rhG-HGF)均能诱导下肢缺血区域的血管生成[1].本实验旨在兔下肢缺血模型上观察rhG-CSF和rhG-HGF联合应用对缺血肢体侧枝血管新生的影响.     

CO2促缺血下肢侧支循环建立的实验研究

目的：观察经股动脉主射CO2对兔缺血下肢侧支循环形成作用。方法：采用新西兰大白兔，建立兔急性下肢缺血模型。将模型兔分成两组，实验组10条，每日经股动脉注射95％的CO2（2ml/kg）；对照组6条，每日只注射与实验组等量的肝素生理盐水，共20d，20d后行血管造影、病理、免疫组化染色检查，评价各组侧支血管形成状况。结果：实验组较对照组动物下肢缺血部位新生血管明显增多，侧支循环形成。结论：CO2能加速扩张下肢动脉侧支血管，加速缺血区动物侧支循环的建立，增加下肢缺血区微血管的密度，改善缺血区的血液供应，并有效的保护下肢功能。     

骨髓单个核细胞和骨髓源内皮祖细胞移植促进血流重建的比较研究

目的 比较骨髓单个核细胞(MNCs)和骨髓源内皮祖细胞(EPCs)移植促进血流重建的效果,探讨非内皮祖细胞在血流重建中的作用.方法 获取Lewis大鼠骨髓MNCs,部分MNCs在体外诱导分化为EPCs.采用Lewis大鼠建立单侧后肢缺血模型.建模后3 d,将模型鼠随机分为3组:(1)对照组(n=6),将0.8 mL D-Hank's液注入对照组大鼠缺血侧后肢;(2)MNC组(n=6),将8×10~6个骨髓MNC植入MNC组大鼠缺血侧后肢;(3)EPC组(n=6),将体外培养的8 × 10~6个EPC植入EPC组大鼠缺血侧后肢.细胞移植后3周行大鼠后肢动脉造影,检测缺血侧后肢侧支血管数;切取缺血侧后肢腓肠肌,分别行CD31和α-SMA免疫组化染色,计算毛细血管密度和小动脉密度.结果 MNC组毛细血管密度与EPC组差异无统计学意义[(31.67 ± 7.87)个/HP vs.(32.83±5.38)个/HP,P＞0.05].而均高于对照组(19.67 ± 4.80个/HP)(P＜0.05);MNC组侧支血管数与EPC组差异无统计学意义[(4.17±0.75)个vs.(4.50 4±1.38)个,P＞0.05],但均高于对照组[(2.50 ± 1.5)个](P＜0.05);MNC组小动脉密度与EPC组差异无统计学意义[(4.83 ± 1.47)个vs.(5.50 ± 2.35)个,P＞0.05],亦均高于对照组[(2.17±0.98)个](P＜0.05).结论 在骨髓干细胞移植治疗肢体缺血性疾病中,非内皮祖细胞在血流重建中所起的作用与EPC相似.     

补肾生血药促进大鼠缺血后肢血管新生的实验研究

目的:探讨补肾生血药对缺血后肢大鼠外周循环中骨髓来源内皮祖细胞(EPC)的影响及缺血组织血管新生的影响。方法:建立大鼠后肢缺血模型,喂食补肾生血药,1周后细胞培养观察外周血EPC数量变化,4周后检测缺血组织微血管密度及血管内皮生长因子(VEGF)的表达情况。结果:实验组大鼠外周血培养的EPC(89.1±10.3/mm2)明显高于对照组(48.6±7.5/mm2)(P<0.01),缺血组织微血管密度(288.76±12.54)和VEGF表达(0.233±0.014)均高于对照组(224.84±5.87),(0.162±0.018,P<0.05),且外周血EPC数量与微血管密度之间具有显著相关性(P<0.01)。结论:补肾生血药通过动员骨髓EPC的迁移、分化、促进局部的血管新生,达到改善供血目的。     

人脐血内皮祖细胞治疗裸鼠心肌梗死

目的 探讨人脐血内皮祖细胞(EPCs)移植治疗裸鼠心肌梗死的可行性.方法 采用淋巴细胞分离液提取人脐血单个核细胞(MNCs),应用添加诱导因子的培养基于体外诱导分化并于培养7 d后进行鉴定.采用20只裸鼠建立心肌梗死模型后,将体外诱导分化7 d并摄取CM-Dil的内皮祖细胞通过尾静脉注射进行细胞移植到实验组,对照组注射培养基.2周后计数心梗区域新生毛细m管密度及心梗面积并于荧光显微镜下观察新生血管的荧光.结果 体外诱导7 d后贴壁细胞CD34阳性率达(50.48±5.17)%,CDl33阳性率达(19.12±4.37)%.实验组平均梗死面积为(8.27±1.64)%,对照组为(14.30±2.84)%(t=-4.78,P<0.05);实验组每高倍视野平均新生血管密度为14.29±1.38,对照组为10.17±1.72(t=4.71,P<0.01);行荧光显微镜下观察实验组新生血管有红色荧光.讨论人脐血单个核细胞在体外诱导分化为内皮祖细胞,进行细胞移植到建立心梗模型的裸鼠后可在心梗区域形成新生血管,从而并改善梗死部位心脏功能.     

动脉Ⅲ号方对大鼠缺血下肢血管新生的影响

目的:观察动脉Ⅲ号方对大鼠缺血下肢的影响。方法:选取雄性SD大鼠72只,在麻醉下结扎大鼠左下肢股动脉及其分支,并切断股动脉,制作下肢缺血模型。将制作成功的模型随机均分为模型组、动脉Ⅲ号方高、中、低剂量组和粒细胞集落刺激因子(rhG-CSF)组,同时设假手术组(麻醉后暴露股动脉),每组12只。测量并比较各组大鼠的双下肢温差,检测并比较大鼠外周血CD34阳性细胞比例,观察并比较大鼠左下肢术后创面愈合情况及腓肠肌毛细血管数目。结果:与模型组比较,动脉Ⅲ号方给药组和rhG-CSF组能降低大鼠下肢温差(P＜0.05),提高CD34阳性细胞比例(P＜0.05),提高腓肠肌微血管数(P＜0.05),促进创面愈合。结论:动脉Ⅲ号方能提高大鼠外周血CD34阳性细胞比例,促进缺血组织血管新生。     

骨髓间充质干细胞联合肝细胞生长因子基因治疗兔肢体缺血

目的探讨联合应用骨髓间充质干细胞(BMSC)和肝细胞生长因子(HGF)基因治疗兔肢体缺血的疗效。方法 32只新西兰兔切除右后肢股浅动脉并结扎股深动脉建立后肢缺血模型,成模后随机均分为空腺病毒对照组(对照组),BMSC细胞治疗组(BMSC组),HGF基因治疗组(HGF组)和联合治疗组(BMSC+HGF组),各组均采用术肢肌肉内原位注射。治疗28 d后通过动脉造影行侧枝血管计数,治疗30 d后用免疫组化和Western blot法检测注射点周围组织中CD31和HGF的表达。结果 BMSC组及HGF组的侧支血管计数与对照组间差异无统计学意义,而BMSC+HGF组侧支血管计数较其余各组明显增加(P<0.05或P<0.01);免疫组化显示,各处理组CD31表达量明显高于对照组(P<0.05或P<0.01),BMSC组和HGF组间CD31表达量无明显差异(P>0.05),但两者均明显低于BMSC+HGF组(均P<0.05);Western blot显示,各处理组HGF表达量均高于对照组(P<0.05或P<0.01),且HGF在BMSC组、HGF组和BMSC+HGF组中的表达量依次增高,差异均有统计学意义(均P<0.05)...     

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.     

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.     

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.     

Dilemma of Membrane Biocompatibility and Reuse

Abstract: Numerous articles have been published on the multiple use of dialyzers and on the effect of different reprocessing chemicals and techniques on the dialyzer biocompatibility and performance. The results often appear contradictory, especially those comparing standard biocompatibility parameters. Despite this confusion, a discerning review of the published works allows certain limited conclusions to be drawn. Reprocessing of used hemodialyzers changes the biocompatibility profile of a dialyzer as defined by the parameters complement activation. leukopenia, and cytokine release. The effect of reprocessing depends on the chemicals and reprocessing technique applied and also on the type of membrane polymer being subjected to the reprocessing procedure. Reports of pyrogenic reactions indicate that the flux of the membrane also influences how suitable it is for safe reuse. An increased risk of allergic and pyrogenic reactions appears to be associated with dialyzer reuse. Furthermore, there has been a lack of investigations into the immunologic effect of the layer of adsorbed and chemically altered proteins that remains on the inner surface of reprocessed dialyzers. We conclude that the clinical benefit of dialyzer reuse cannot be generally accepted from a biocompatibility point of view.     

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.