尾静脉注射bFGF对大鼠脊髓损伤的早期影响

目的:比较不同途径应用碱性成纤维细胞生长因子(basicfibroblastgrowthfactor,bFGF)对大鼠脊髓损伤早期水、钙、镁离子的影响,探讨静脉应用bFGF的可行性。方法:AllenWD(Weightdrop)技术,以10g×25cm致伤力造成大鼠T8急性脊髓不完全损伤,不同途径用药比较。术后2h、6h及24h切取伤区脊髓组织检测水、钙、镁离子变化。结果:受损伤脊髓组织水含量增多,钙离子水平增高,镁离子水平下降,而蛛网膜下腔应用bFGF及尾静脉注射bFGF均能明显改变上述变化。结论:脊髓损伤早期静脉应用bFGF同样对脊髓损伤具有保护作用。     

脊髓损伤后低剂量FK506对伤段组织电解质水含量失衡的早期保护作用

[目的]探讨脊髓损伤后早期应用低剂量抗移植排斥药物—FK506对伤段脊髓组织钙、镁离子及水含量的影响,明确其神经保护作用的可能机制。[方法]35只雄性Wistar大鼠随机分为对照组、损伤组和治疗组。采用Allen＇s打击法制作脊髓损伤模型,对照组仅做椎板切除术。治疗组在脊髓损伤后5min一次性经尾静脉注射FK506（0.3mg/kg）,其余两组以相同方法给予0.9%的生理盐水。术后6、12、24h取材,采用干湿法测定伤段脊髓组织水含量,以原子吸收光谱分析法测定钙、镁离子含量。[结果]伤段脊髓组织中水含量及钙离子水平升高,两者均于伤后12h达高峰,而镁离子水平降低,应用FK506可显著改善上述变化（P〈0.05,P〈0.01）。[结论]低剂量FK506可减轻伤段脊髓组织水肿和电解质失衡,对继发性脊髓损伤具有神经保护作用。     

bFGF保护脊髓组织、促进神经再生的实验研究

目的　探讨应用外源性碱性成纤维细胞生长因子 (basicfibroblastgrowthfactor,bFGF)对脊髓损伤的保护作用以及促进脊髓神经再生的影响。方法　利用Allen氏WD (Weightdrop ,WD)技术 ,以 10 g× 2 5cm致伤力造成SD大白鼠T8脊髓损伤模型 ,并于损伤平面以下蛛网膜下腔置细塑料导管。治疗组分别于术后即刻、 1、 2、 3、 4、 8、 12、 2 4及 48h经导管注入bFGF溶液 2 0 μl (含bFGF10 0 μ) ,以后每周经导管注入 2 0 μlbFGF ;对照组则在同时间注入等量生理盐水 ,术后取伤区脊髓组织进行形态学观察及特殊染色 ,观察神经纤维再生情况。结果　伤区白质内髓鞘结构紊乱 ,囊性变严重 ,应用bFGF可明显改善 ;Gless染色发现bFGF治疗组神经纤维生长情况明显优于生理盐水对照组 ,Fast-blue染色发现bFGF治疗组脊髓变性较轻 ,经统计学分析两组差异有显著性意义 (P <0 0 1)。结论　脊髓损伤后应用外源性bFGF可以保护脊髓神经组织 ,并且对神经纤维有明显的促进作用。     

硫酸镁对继发性脊髓损伤保护作用的实验研究

目的：探讨硫酸镁对继发性脊髓损伤的保护作用及其作用机制。方法：选健康新西兰大白兔36只，随机分为3组：A组为正常组，仅行L1～L3椎板减压；B组和C组分别为对照组和治疗组，行L1～L3椎板减压后采用Allen’s重物打击法致伤脊髓．伤后30min时B组经腹腔注射蒸馏水600mg／kg，C组经腹腔注射硫酸镁600mg／kg。48h后切取伤段脊髓组织分别测定水、钙、镁含量，观察局部组织病理学改变、超微结构变化及单位面积凋亡细胞数。结果：与A组比较，B、C组伤段脊髓组织水、钙含量增多，镁含量减少，组织病理学改变及超微结构破坏严重，细胞凋亡数上升，且C组较对B组轻。结论：早期应用硫酸镁治疗可减轻脊髓损伤后的继发性损伤。     

NGF、BDNF基因修饰嗅鞘细胞脊髓内移植对损伤脊髓细胞的保护作用

目的：观察神经生长因子(nerve growth factor，NGF)和脑源性神经营养因子(brain-derived neurotmphic fac-tor，BDNF)基因修饰的嗅神经鞘细胞(Olfactory ensheathing cells，OECs)移植对损伤脊髓组织的保护作用。方法：将脊髓半横断伤SD大鼠模型，随机分为：NGF、BDNF基因修饰的OECs移植组(A组)、OECs移植组(B组)、损伤对照组(C组)和正常对照组(D组)。24h后每组8只动物取伤段标本，测水离子含量。其余动物第6周和12周每组8只动物爬坡试验，评价下肢运动功能及运动诱发电位(MEP)检测。结果：脊髓损伤(SCI)后组织水肿，Na^ 、Ca^2 离子浓度升高，K^ 、Mg^2 离子浓度降低。NGF、BDNF、基因修饰的OECs脊髓内移植后显著改善这些变化，且使SCI后神经功能有显著恢复。结论：NGF、BDNF基因修饰的OECs脊髓内移植对SCI有保护作用。其机制可能与减少神经细胞离子失衡，改善细胞内环境有关。     

碱性成纤维细胞生长因子对脊髓损伤早期保护作用的实验研究

目的　探讨碱性成纤维细胞生长因子（ｂ Ｆ Ｇ Ｆ）对脊髓损伤的早期保护作用。方法　选３４ 只 Ｓ Ｄ 大鼠,随机分为正常组、对照组和治疗组,采用 Ａｌｌｅｎ 氏技术,以１０ ｇ×２．５ ｃｍ 致伤力造成大鼠 Ｔ８ 急性脊髓损伤,并于损伤平面以下蛛网膜下腔置入细塑料管,治疗组给予ｂ Ｆ Ｇ Ｆ治疗,对照组同时注入生理盐水。术后切取损伤区脊髓组织进行形态学观察和生化指标测定。结果受损伤段脊髓组织水含量增多,钙离子水平升高,镁离子水平下降,白质内髓鞘结构紊乱,囊性变严重,而ｂ Ｆ Ｇ Ｆ可明显改变上述变化。结论　ｂ Ｆ Ｇ Ｆ对脊髓损伤早期的继发性损害有保护作用。     

神经生长因子保护受伤脊髓组织的实验研究

为了解神经生长因子（ＮＧＦ）对损伤的脊髓组织的作用，采用Ａｌｅｎ氏ＷＤ装置，以１０ｇ冲击棒自２．５ｃｍ高度下落撞击ＳＤ大鼠Ｔ８脊髓，并于蛛网膜下腔内置入导管。术后，实验组经导管注入ＮＧＦ溶液；对照组则注入生理盐水。术后４，８及２４ｈ，取脊髓损伤段标本，分别经干湿法、原子吸收光谱法测量水、钙含量。结果发现：损伤脊髓段组织钙含量明显增高，组织水肿严重；脊髓损伤后，应用ＮＧＦ可显著改善这些变化。这一实验结果证实ＮＧＦ对受伤的脊髓有明显的保护作用，其保护作用与稳定钙离子水平有关。     

碱性成纤维细胞生长因子对大鼠牵张性脊髓损伤后细胞凋亡及基因表达的影响

目的观察碱性成纤维细胞生长因子(bFGF)对牵张性脊髓损伤后细胞凋亡及相关基因表达的影响,探讨bFGF对脊髓损伤保护作用的分子机制。方法大鼠脊髓T13～L2经牵张损伤,皮层体感诱发电位(CSEP)监测P1～N1波幅下降至术前波幅70%后,于损伤平面以下经蛛网膜下腔置细导管,治疗组分别于术后即刻1、2、3、4、8、12及24h经细导管注入bFGF溶液20μl(含bFGF20μg),对照组在相同时间注入等量生理盐水,然后于术后6h、1、4、7、14及21d处死取材,采用原位末端标记法(TUNEL)及免疫组织化学观察脊髓细胞凋亡及p53、bax、bcl2表达的变化情况,应用电生理观察大鼠的神经功能情况,并进行对比分析。结果术后4、7、14、21d,治疗组TUNEL法染色阳性细胞数明显低于对照组(P<0.01)。术后4、7、14、21d,治疗组p53、bax的阳性细胞数明显低于对照组,治疗组各时相点bcl2的阳性细胞数明显高于对照组,治疗组大鼠的神经功能恢复与对照组相比差异有统计学意义(P<0.01)。结论bFGF能通过抑制p53、bax蛋白的表达及促进bcl2蛋白表达来抑制牵张性脊髓损伤后细胞凋亡,从而保护损伤的脊髓组织,这可能是bFGF对脊髓损伤具有的保护作用机制之一。     

热休克蛋白70在大鼠急性打击损伤脊髓中的表达

目的观察急性打击损伤大鼠脊髓组织中热休克蛋白70（heat shock protein70，HSP 70）的表达。方法65只大鼠随机分为3组：正常对照组5只、手术对照组和脊髓损伤组各30只，采用改良Allen法建立脊髓损伤动物模型。手术对照组和脊髓损伤组分别于处置后的2h、6h、12h、24h、48h、72h这6个时间点各采集5只大鼠的脊髓。应用免疫组织化学染色方法观察不同时点各组脊髓中热休克蛋白的表达变化。结果在大鼠正常胸段脊髓中没有基础性HSP70的表达。打击造成急性脊髓损伤后2h，脊髓组织内出现HSP70的表达，损伤后24～48h脊髓组织中HSP70染色达到高峰，并维持至损伤后72h。结论在遭遇损伤性刺激后，脊髓组织在随后的2～72h内HSP70的表达明显增加；HSP70可能在阻止脊髓的继发性损伤方面发挥一定的作用。     

汉防己甲素治疗急性脊髓损伤的实验研究

目的 探讨汉防己甲素(Tetrandrine，Tet)对急性脊髓损伤(Acute spinal cord injuries，ASCI)的保护作用。方法 74只Wistar大鼠随机分为4组，用改良Allen’s打击法制备大鼠截瘫模型，造模前各组分别投给相应的药物，伤后1h、4h取损伤区脊髓组织进行形态学观察和生化指标测定。结果 汉防己甲素能明显降低组织钙总量和MDA含量，防止镁总量和SOD含量的下降，稳定6-Keto-PGFla／TXB2的比值，减轻组织病损。结论 Tet对ASCI有保护作用，其作用机制为①扩张微血管，改善微循环，逆转ASCI后早期缺血倾向；②抗氧自由基，减轻组织过氧化损伤，稳定生物膜性结构；③减少ASCI后钙内流，从而阻断继发性损伤的链式反应。     

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.     

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.     

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.