脊髓急性损伤后神经细胞凋亡的时相和空间分布特点

目的 研究脊髓急性损伤后神经细胞的凋亡及其时相和空间特点。方法 大鼠脊髓（T8,9）经中度压迫损伤后,分别在30min、2h、4h、8h、24h、48h、72h、7d、14d、和21d处死取材（n=4)。应用HE、Nissl染色及凋亡细胞原位末端标记法对脊髓组织进行标记。结果 损伤4h后,在损伤段及邻近段可见末端标记阳性神经细胞,损伤段灰质中阳性细胞数8h达高峰,24h白质中阳性胶质细胞数量达高峰。相邻节段阳性细胞数量在72h达高峰。阳性细胞以白质中胶质细胞为主,主要分布于相邻节段。结论 脊髓损伤后神经细胞凋亡是继发损伤期的重要病理变化,并有其时相和空间分布特点。     

大鼠脊髓急性损务后神经细胞凋亡及相关基因表达

目的：研究脊髓急性损伤后神经细胞的凋亡及相关基因的表达,方法：大鼠脊髓（T8、T9）经中度压迫损伤后,分别在30min,2h,4h,8h,24h,48h,72h,7d,14d和21d处死取材（各间组n=4)。应用HE染色、免疫组化及凋亡细胞原位未端标记法对脊髓组织进行标记。结果：损伤4h后,在损伤段及邻近段可见末端标记阳性神经元,损伤段灰质中阳性细菌数8h达高峰,24h白质中阳性胶质细胞数量达高峰。相邻节段阳性细胞数72h达高峰。损伤后P53及Bax大量表达,而Bcl-2仅少量表达。结论：脊髓损伤后神经细胞的凋亡发损伤期的重要病理变化。     

大鼠脊髓急性损伤后神经细胞凋亡及相关基因表达△

目的研究脊髓急性损伤后神经细胞的凋亡及相关基因的表达.方法大鼠脊髓(T8、T9)经中度压迫损伤后,分别在30min、2h、4h、8h、24h、48h、72h、7d、14d和21d处死取材(各时间组n=4).应用HE染色、免疫组化及凋亡细胞原位末端标记法对脊髓组织进行标记.结果损伤4h后,在损伤段及邻近段可见末端标记阳性神经元,损伤段灰质中阳性细胞数8h达高峰,24h白质中阳性胶质细胞数量达高峰.相邻节段阳性细胞数72h达高峰.损伤后P53及Bax大量表达,而Bcl-2仅少量表达.结论脊髓损伤后神经细胞的凋亡是继发损伤期的重要病理变化.     

脊髓损伤后凋亡调控基因Bcl-2、Bax的表达及意义

目的：观察探讨大白鼠脊髓损伤后细胞凋亡及调控基因Bcl-2、Bax的表达及意义。方法：28只SD大鼠随机分为7组，Allen’s法致伤脊髓，于术后4、8、24、48、72、168h采集脊髓标本，1组作为对照组，分别行HE染色、TUNEL染色和免疫组化技术检测Bcl-2、Bax的表达。结果：TUNEL染色显示有神经元和胶质细胞凋亡。Bcl-2在术后4h开始出现阳性表达，24h达高峰。Bax术后4h出现阳性表达，8h时达高峰。结论：脊髓损伤后存在神经元和胶质细胞的凋亡，Bcl-2、Bax基因对调控细胞凋亡可能具有重要作用。     

脊髓损伤后凋亡调控基因Bcl-2、Bax的表达及意义

目的:观察探讨大白鼠脊髓损伤后细胞凋亡及调控基因Bcl-2、-Bax的表达及意义.方法:28只SD大鼠随机分为7组,Allen‘s法致伤脊髓,于术后4、8、24、48、72、168h采集脊髓标本,1组作为对照组,分别行HE染色、TUNEL染色和免疫组化技术检测Bcl-2、Bax的表达.结果:TUNEL染色显示有神经元和胶质细胞凋亡.Bcl-2在术后4h开始出现阳性表达,24h达高峰.Bax术后4h出现阳性表达,8h时达高峰.结论:脊髓损伤后存在神经元和胶质细胞的凋亡,Bcl-2、Bax基因对调控细胞凋亡可能具有重要作用.     

大鼠脊髓损伤后细胞凋亡的光镜和电镜观察

目的：观察大白鼠脊髓损伤后细胞凋亡现象及超微结构特点，方法：48只SD大鼠为分两组，Allen's法致伤脊髓（轻度损伤和中度损伤），分别于术后4、8、24、48、72、168h处死，采集脊髓标本，应用HE、TUNEL当色进行光镜和电镜观察，结果：HE当色显示轻度损伤后 髓主要表现为多发性小出血灶，后期为胶细胞增生，中度损伤早期主要表现为大片出血灶，继之出现损伤部位细胞液化坏死，后期空腔形成。TUNEL染色显示，术后4h即出现细胞凋亡，术后8h达最高峰，包括神经元和胶质细胞凋亡。术后48h开始减少，术后72h和168h仍可见到凋亡的胶质细胞，术后4h和8h凋亡细胞主要分布在损伤节段内，结论：脊髓损伤后存在细胞凋亡现象，从形态上看包括神经元和胶质细胞和凋亡，细胞是脊髓继发性损害中细胞死亡的一种重要形式。     

脊髓损伤后凋亡调控基因Bcl-2、Bax的表达及意义

目的 :观察探讨大白鼠脊髓损伤后细胞凋亡及调控基因Bcl -2、Bax的表达及意义。方法 :2 8只SD大鼠随机分为 7组 ,Allen′s法致伤脊髓 ,于术后 4、 8、 2 4、 48、 72、 168h采集脊髓标本 ,1组作为对照组 ,分别行HE染色、TUNEL染色和免疫组化技术检测Bcl -2、Bax的表达。结果 :TUNEL染色显示有神经元和胶质细胞凋亡。Bcl-2在术后 4h开始出现阳性表达 ,2 4h达高峰。Bax术后 4h出现阳性表达 ,8h时达高峰。结论 :脊髓损伤后存在神经元和胶质细胞的凋亡 ,Bcl-2、Bax基因对调控细胞凋亡可能具有重要作用。     

脊髓半切伤神经细胞凋亡的实验研究

目的 探讨细胞凋亡在脊髓半切损伤发病机理中的作用。方法 采用原位末端标记法，对大鼠半切伤的不同时间的凋亡细胞数目和部位进行观察分析，并作正常对照。结果半切后的灰质和自质均有细胞凋亡，神经元凋亡后形成空泡，胶原细胞凋亡多见。细胞凋亡发生在损伤后12h，7d达高峰，至5周趋于正常。结论 大鼠脊髓半切伤后神经元和胶质细胞均发生凋亡，而胶质细胞凋亡常见。     

亚低温对脊髓损伤后神经细胞凋亡的影响

目的观察大鼠脊髓损伤(SCI)细胞凋亡现象及亚低温对细胞凋亡的影响。方法大鼠SCI后分别于8h、24h、7d取材，采用常规病理HE染色和末端脱氧核苷酸转移酶(TdT)介导的dutp缺口末端标记技术(TNEUL)，研究亚低温对大鼠SCI后神经细胞凋亡的影响。结果SCI后常温组8h灰质区出现较多凋亡细胞，24h时白质和灰质内均有凋亡细胞分布，7d后凋亡细胞多见于白质；亚低温组凋亡细胞明显减少(P＜0．05)。结论亚低温明显减少SCI后细胞凋亡的发生，从病理上为亚低温脊髓保护提供了可靠的依据。     

大鼠牵张性脊髓损伤后细胞凋亡及相关基因表达的实验研究

目的观察大鼠牵张性脊髓损伤后细胞凋亡现象,检测脊髓损伤后凋亡相关基因的表达。方法大鼠脊髓T13～L2经牵张损伤,皮层体感诱发电位(CSEP)监测P1N1波幅下降至术前波幅70%后,分别于术后30min、6h、1、4、7、14、21d处死大鼠,取材(n=4)。应用流式细胞仪、原位末端脱氧核糖核苷酸转移酶介导dUTP标记(TUNEL)技术观察脊髓细胞凋亡情况,用免疫组化检测p53、bax和bcl2的表达。结果流式细胞仪及TUNEL法检测显示,损伤组术后6h凋亡细胞开始增多,术后7d细胞凋亡率达高峰,随后开始回落,持续21d,与空白对照组及椎板切除组比较,差异有显著性意义(P<005,001)。TUNEL法染色显示,白质中出现大量胶质细胞凋亡。免疫组化染色显示损伤组术后6h开始,p53、bax和bcl2阳性表达开始增多,p53阳性细胞数术后4d达高峰,bax和bcl2术后7d达高峰,损伤组各时相点的阳性表达与空白对照组与椎板切除组比较差异有显著性意义(P<005,001)。结论牵张性脊髓损伤后存在细胞凋亡现象,从形态上看包括神经元和胶质细胞凋亡,细胞凋亡是牵张性脊髓损伤继发损害中细胞死亡的一种重要形式,也是继发损伤期的重要病理变化。凋亡相关基因p53、bax大量表达,可能在脊髓细胞凋亡过程中起重要作用。     

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.