神经“借干”修复周围神经缺损的实验研究

目的 探讨周围神经缺损的修复方法.方法 取SD雄性大鼠54只,切取右侧腓总神经10 mm,建立大鼠腓总神经缺损模型,随机分为3组,每组18只.A组为神经“借干”修复组,将腓总神经的远、近断端均修剪成45°斜面,在胫神经干相应外膜上开窗,分别行神经外膜端侧缝合;B组为远断端端侧缝合组,将腓总神经的近端结扎并翻转缝于邻近肌肉内,将腓总神经远断端修剪成45°斜面,相应胫神经干外膜开窗,行端侧缝合;C组为自体神经回植组(对照组),将切取的腓总神经原位回植.术后20周,对各组大鼠进行神经电生理和病理组织学检测.结果 术后20周,A组的神经传导速度、胫前肌复合动作电位、有髓神经纤维计数均优于B组(P＜0.05),与C组比较差异无统计学意义(P＞0.05).结论 对于大鼠周围神经缺损,神经“借干”修复方法是可行的.     

神经端侧缝合在周围神经长段缺损修复中的应用

目的 :用神经端侧缝合法修复周围神经长段缺损 13例 ,对其疗效进行评定和分析。方法 :10例采用供体神经束、膜开窗 ,将受损神经远断端以 45°角端端缝合于供体神经“窗口” ,3例供体神经束、膜开窗 ,受损神经因缺损过长 ,远断端借一段腓肠神经端侧缝合于供体神经“窗口”。结果 :术后随访 13～ 3 6个月 ,优 (M 4S3 ) 7例 ,良 (M 3S4) 3例 ,可 (M 2S2 ) 2例 ,差 (M 1S1) 1例 ,优良率为 76.9%。结论 :神经端侧缝合后通过侧支再生 ,为临床克服难修复的周围神经长段缺损提供了良好的方法     

不同吻合面积影响神经端侧吻合法修复效果的实验研究

目的比较神经端侧吻合处不同接触面积对周围神经端侧吻合后神经再生的影响,观察面积因素在神经端侧吻合法中的作用。方法选用50只健康SD大鼠,采用右侧腓总神经损伤修复模型。术中根据手术修复方法不同,分为A、B两组,每组25只。每组将右侧腓总神经在其坐骨神经分支后3mm处局部封闭,利刀切断,吻合于胫神经。A组神经远断端切成45°斜面,腓总神经与胫神经端侧吻合;B组神经远断端切成10°斜面,腓总神经与胫神经行端侧吻合。术后第8周分别对三组大鼠进行组织形态学、腓肠肌湿重检测、肌电图、有髓神经纤维计数和神经示踪法观察。结果B组肌湿重检测、肌电图、有髓神经纤维计数检测指标在8周时与A组比较,各项检测指标均存在明显差异（P〈O．05）。结论增大神经断端接触面积后行神经端侧吻合法修复神经,神经纤维再生良好;增大神经断端接触面积能获得更有效的神经再生;长人远端的神经纤维多少与受端吻合接触面积大小有关。     

鼠周围神经端侧缝合与侧侧缝合修复方式的比较研究

目的　进一步探讨神经缝合修复方式对神经再生的影响。　方法　将SD鼠分为两组。端-侧缝合组将腓神经远侧断端与去外膜胫神经（开窗）行端侧缝合,开窗大小相当于腓神经的直径。侧-侧缝合组将腓神经远侧断段侧壁去除外膜,同样胫神经侧壁去外膜,两者去除外膜的面积相当于腓神经直径的3倍。将去外膜的两神经干进行侧-侧缝合。通过足印分析法,组织学方法,电生理,神经纤维密度等测量。比较两种修复法神经再生质量。　结果　术后16周时端-侧组和侧-侧组腓神经功能指数分别为(－39.92±11.67)和（-64.49±31.31）（P=0.033）,有显著差异。电生理术后16周侧-侧组腓神经潜伏期（Lat）(1.17±0.26)、波幅（Amp）(24.9±3.59)优于端-侧组Lat(1.42±0.06)、Amp(16.5±7.04)。组织学检查显示侧-侧组神经纤维密度(4330±672)较端-侧组(3186±199)高。　结论　鼠类腓-胫神经侧-侧缝合对神经再生有益。     

周围神经端侧缝合与端端缝合疗效比较的实验研究

目的比较周围神经损伤后端侧缝合与端端缝合方法疗效的优劣。方法ＳＤ大鼠１２只,按手术先后随机分成Ａ,Ｂ两个时间组。左侧腓总神经切断后作端端缝合。右侧腓总神经切断后,远断端与近断端上方０．５ｃｍ束外膜开窗处作自身端侧缝合。分别于术后１、３个月时作肌电图后取材,测肌湿重及作组织学检查。结果Ａ、Ｂ两组,端侧缝合与端端缝合比较,肌电图中诱发电位潜伏期延长、波幅降低。胫前肌肌湿重减轻。肌纤维截面积、有髓神经纤维数均减少。经配对ｔ检验,Ｐ值均＜０．０５。结论周围神经断伤作端侧缝合后,其神经再生质量不及端端缝合优良。     

周围神经端侧动脉套接后神经再生的研究

目的研究周围神经端侧动脉套接后神经再生的可能性及其特点. 方法取SD大鼠75只,在股骨中下段切断腓神经,将近断端逆转90度包埋于肌肉中.随机分为5组.A组:将截取的左颈总动脉套接于右侧正常胫神经侧方与腓总神经远端2 mm距离之间,缝合部胫神经外膜不予切除;B组:在胫神经套接部外膜开窗1.0 mm;C组:腓总神经切断14天后再予动脉套接,余同B组;D组:同B组,且于动脉套接部注入神经生长因子(neural growth factor, NGF)1 ml;E组:将腓总神经远端以端侧缝合形式直接缝合于胫神经的一侧,外膜开窗1.0 mm.术后4、8和12周分别行组织学、电镜和神经纤维计数等检查. 结果 4周时C、D及E组周边区域有神经纤维轴突和髓鞘再生,A组则无神经纤维生长; 8周时C、D及E组再生神经纤维较B组多,E组神经纤维较C、D组多,差异有统计学意义(P<0.05); 12周时C、D及E组神经纤维多于B组,差异有统计学意义(P<0.05);C组及D组有较丰富的神经再生,与神经端侧直接吻合的E组差异无统计学意义(P>0.05). 结论神经端侧2 mm距离动脉套接可作为修复周围神经损伤的一种可行方法.     

不同端侧缝合方法对周围神经再生的影响

目的比较各种不同的端侧缝合方法治疗周围神经损伤后神经再生的优劣。方法ＳＤ大鼠９０只，随机分成５组。前４组右侧腓总神经作端侧缝合，左侧切除长１．５ｃｍ的腓总神经作为对照。Ａ组：右侧远断端与近段行侧端吻合，外膜不开窗。Ｂ组：方法同Ａ组，但束、外膜开窗。Ｃ组：右侧近断端与远段行端侧吻合，外膜不开窗。Ｄ组：方法同Ｃ组，但束、外膜开窗。Ｅ组：右侧以４５度角、左侧以９０度角作侧端缝合。各组分别于术后１、２、３个月取材，作肌电图、组织学及肌湿重检查。结果Ａ与Ｂ，Ｃ与Ｄ组比较，运动神经诱发电位潜伏期、波幅及有髓纤维计数，后者优于前者（Ｐ＜０．０５）。肌湿重及肌纤维截面积，两者无明显差异（Ｐ＞０．０５）。４５度与９０度角比较，前者神经再生质量明显优于后者（Ｐ＜０．０５）。结论周围神经可通过端侧吻合而再生，以束、外膜开窗及４５度角的缝合方法为佳     

周围神经侧侧缝合法的实验研究

目的 提出一种修复周围神经操作的新方法－－侧侧缝合法,并对侧侧缝合后神经的再生模式进行初步研究。方法 选用ＳＤ雄性大鼠１２只,双下肢随机分为实验侧和对照侧。实验侧：将腓总神经在大腿下１／３处切断,断端结扎后将其远端与相邻胫神经干适当松解后靠拢,纵行切开两神经相邻侧面的神经外膜、束膜长约０．５ｃｍ,至部分神经纤维外露。紧密对合两切开面后缝合束膜、外腊。对照侧：腓总神经在相同部位切除０．５ｃｍ,至部分     

大鼠神经端侧缝合的实验研究

目的：为进一步了解神经端侧缝合后再生的可能性。方法：用大鼠进行研究，实验分五组：Ａ组，将切断的腓神经远端与正常胫神经干行端侧缝合，保留缝合部胫神经外膜；Ｂ组，同Ａ组，缝合部胫神经外膜予以去除（“开窗”）；Ｃ组，将一神经移植段的两端分别与正常胫神经干和切断的腓神经远端神经干行“开窗”的端侧缝合；Ｄ组，将胫神经切断，近端与切断的腓神经远端神经干行“开窗”的端侧缝合。Ｅ组对照：仅切断腓神经。术后不同时期分别行电生理、组织学、神经纤维计数等检查。结果：鼠神经端侧缝合后腓神经远端有不同数量的有髓神经纤维再生。结论：动物鼠类神经端侧缝合能够再生     

侧侧缝合法治疗不完全性周围神经损伤的实验研究

目的： 种新的治疗不完全性周围神经损伤的方法一侧侧缝合法，并对其疗效进行初步的实验研究。方法：SD大鼠12只，双下肢随机分为实验侧和对照侧。将两侧腓总神经在相同部位以相同的力度钳夹损伤；实验侧将损伤的腓总神经远端与胫神经靠拢后，切开相邻面的束、外膜，互相侧侧缝合，对照侧不作进一步处理。3个月后，对神经的再生情况进行肌电图、组织学等检查。结果：实验侧腓总神经远端有良好的神经再生，再生的神经纤维质量与对照侧相比有显著差异（P＜0．05）。结论：不完全性周围神经损伤经侧侧缝合修复，可以获得较好的再生；侧侧缝合法是一种新的修复不完全性周围神经损伤的方法。     

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.     

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.