天然羟基磷灰石/壳聚糖复合材料骨相容性研究(一)

目的：观察天然羟基磷灰石（Hydroxyaptitc HA）／壳聚糖（chitosan）复合材料（NHC）的骨组织相容性及与骨发生结合的界面情况。方法：将天然羟基磷灰石／壳聚糖复合材料植入兔颅骨中，用CT、三维CT和扫描电镜进行组织形态学方面的观察研究。结果：NHC植入后，植入体周围逐渐形成新骨，胶原成分逐渐成熟并减少。6个月时NHC于周围骨大部分发生融合，10个月时NHC与宿主骨发生牢固结合，成一骨性整体。结论：NHC有良好的骨组织相容性，能与骨发生骨整合。     

等梯度羟基磷灰石涂层植入体的实验研究

目的：观察一种新的等梯度羟基磷灰石（ＨＡ）涂层结构的骨－ＨＡ界面的生物力学及生理学特征。方法：应用经皮质骨植入体模式，在１２条狗的双侧股骨上共植入９６个ＨＡ表面涂层及非涂层钛合金栓。分别于术后６、１２及１８周处死后取材。测定界面抗剪强度并作组织学观察。结果：在要诟任一时间段涂层植入体界面抗剪强度均显著高于非涂层者。涂层植入人体表面成骨活跃，骨与涂层结合紧密，而非涂层植入体表面与骨组织间有纤维组织存     

同种皮质骨融合支架的研制及临床应用

目的研究同种皮质骨融合支架行后路椎间融合术治疗腰椎滑脱的临床疗效。方法对12例腰椎滑脱患者,用同种皮质骨融合支架行后路椎体间融合加内固定术。根据手术前后的椎间隙高度的变化和JOA评分,观察临床疗效。结果12例均获得随访,时间3-6个月,术后椎间隙高度明显恢复,无神经系统并发症,无融合支架脱出,切口无感染,JOA评分术后改善率为93.5%。结论该手术保留的骨性终板有利于防止植入物陷入椎体,能有效地维持椎间隙高度。术中无须取自体骨,且植骨面积最大化,有利于融合,植骨内固定一次完成。同种皮质骨融合支架置入牢固,具有骨传导和骨诱导作用,手术操作简单,是一种良好的椎间融合材料。     

髓核组织对椎间植骨融合的影响

目的：观察椎间盘髓核组织对椎体间植骨融合的影响。方法：11头体重约35kg的丹麦猪接受L3／4和L5／6两个节段的前路椎体间融合器植骨融合手术。其中一个节段在植骨的同时把本节段的全部髓核混合于植骨材料内（A组），另一节段则去除髓核组织行单纯植骨（B组），手术后6周处死猪，分别进行椎间融合器内骨置DEXA骨密度的检查和骨组织计量学检查。结果：A组和B组骨密度分别为0．109和0．150mg/cm^2，两组之间统计学上无显著性差异（P＞05），A组和B组新生骨和未吸收骨骨量分别为9．2％和9．3％，11．1％和12．3％，无显著性差异（P＞0．05），结论：在6周的观察时间内，猪的髓核组织并不影响椎体间植骨的融合。     

骨髓间充质干细胞修复假体周围骨缺损及对假体界面骨整合的影响

[目的]观察骨髓间充质干细胞修复假体周围骨缺损及对假体界面骨整合的影响。[方法]取新西兰大白兔15只。将骨髓间充质干细胞分离、扩增、骨向诱导，体外与珊瑚羟基磷灰石复合构建组织工程骨。将动物双侧股骨髁制作0．6cm×1．2cm的骨缺损，分别植入钛合金植入体，左侧植入体周围骨缺损充填组织工程骨，右侧植入体周围仅充填珊瑚羟基磷灰石为对照组。于术后4周、8周和12周分别行X线检查、扫描电镜、能谱分析及脱钙骨组织学观察。[结果]X线检查示，实验组术后4周缺损区内可见部分骨痂形成，与周围骨质分界清晰；8周可见大量模糊高密度骨痂影；12周缺损区已基本被高密度骨痂所填满，与周围骨质间分界变模糊。对照组4周、8周无明显改变，12周仅边缘有少量的骨痂形成；X射线能谱分析示，不同时间点实验组较对照组内Ca、P的百分含量增高（P〈0．05），随着时间的变化两组Ca、P百分含量都呈增高的趋势。实验组钙／磷比值随时间变化有逐渐升高的趋势，8周时达高峰，随后又降低。组织学结果示实验组术后12周可见明显的新骨形成，但仍可见到未吸收的羟基磷灰石颗粒。对照组各时间点均未见骨长入。[结论]骨髓间充质干细胞骨性诱导后复合珊瑚羟基磷灰石构建组织工程骨可修复假体周围骨缺损，促进假体骨界面骨整合。     

颈前路椎体次全切减压纳米羟基磷灰石/聚酰胺植骨融合内固定治疗脊髓型颈椎病

目的 探讨颈前路椎体次全切减压纳米羟基磷灰石/聚酰胺（n-HA/P66）植骨融合内固定治疗脊髓型颈椎病临床疗效.方法 对2009年6月至2011年6月采用颈前路椎体次全切减压纳米羟基磷灰石/聚酰胺植骨融合内固定手术,治疗40 例脊髓型颈椎病患者的临床资料进行分析,男24 例,女16 例;年龄37～75 岁,平均50.5 岁.病程3个月～9年,平均3年.结果 本组40 例患者于术后6～8个月椎间植骨均达骨性融合,融合率为100%.随访3～12个月,平均8个月.全部患者植骨未出现椎间高度的再丢失,颈椎生理曲度恢复良好,无植骨块松动移位、断板、断钉和滑脱现象发生.40 例患者中,优17 例（42.5%）,良18 例（45%）,可3 例（7.5%）,差2 例（5%）,总有效率为95%.结论 颈前路椎体次全切减压纳米羟基磷灰石/聚酰胺植骨融合内固定手术治疗脊髓型颈椎病安全可行,近期疗效肯定.     

椎间加压融合治疗胸腰椎骨折脱位

目的探讨椎弓根系统椎间加压融合治疗胸腰椎骨折脱位的临床效果，探讨促进早期椎间融合的机制。方法胸腰椎骨折脱位17例，男11例，女6例；年龄23～56岁，平均37．1岁。交通伤10例，高处坠落伤4例，横向挤压伤3例。损伤作用力主要为横向剪切力。A0分型：B1型2例，C1型12例，C2型3例。损伤部位：T10.11 1例，T11．12 1例，T12L13例，L1．2 3例，L2．3 1例，L3.4 2例，L4．5 2例，L5S1 4例。神经功能情况：完全瘫痪4例，不完全瘫痪10例，有不同程度神经根刺激表现3例。手术采用后路减压，植入四枚椎弓根钉，椎间孔充分扩大后撑开椎弓根钉，双侧椎间隙开窗，切除椎体间髓核，刮除中后部软骨板，椎体间植入碎皮质骨，椎弓根系统复位加压，使椎体后缘尽量接触固定，维持加压状态锁紧椎弓根钉系统。术后1周内、3个月、6个月、12个月、18个月复查X线片，测量椎体前后缘椎间高度，观察植骨融合情况。结果术中均无并发症发生。术后16例随访19～37个月，平均25．6个月。患者神经功能部分恢复5例，完全恢复9例。随访X线片显示，加压的椎体间距稳定，植骨均获骨性融合，椎间前部的纤维环骨化明显。无内固定物失败及神经根痛等并发症发生。结论椎弓根系统椎间加压融合治疗胸腰椎骨折脱位，可达到术后早期稳定和早期融合的疗效。     

羟基磷灰石硅胶复合材料修复兔下颌骨骨质缺损的实验研究

为探讨组织代用品羟基磷灰石硅胶复合材料的生物学，在１８只新西兰白兔的双侧下颌骨无牙区制造１０ｍｍ×４ｍｍ×３ｍｍ的骨缺损，置入含羟基磷灰石重量占３０％和７０％的两种块状羟基磷灰石硅胶复合材料。分别于术后２周、１个月、６个月取标本观察。结果表明，两种不同比例的羟基磷灰石硅胶复合材料均无溶解吸收，能与下颌骨形成骨性结合。含羟基磷灰石重量占７０％的羟基磷灰石硅胶复合材料的骨组织亲和性较好，密度接近骨质，且有弹性好、易操作等特点，作为骨代用材料可能有较大应用价值     

假体四种表面处理的体内植入实验

目的探讨骨形态发生蛋白(BMP)与植入体的复合方法及植入体复合BMP后对骨-植入体界面的骨长入与结合强度的作用,为人工关节生物固定方法的改进提供实验依据。方法取12只成年杂种犬,随机分成三个时间组,取双侧股骨为种植区。将多孔金属表面(PCA)植入体、BMP2复合PCA植入体、喷涂羟基磷灰石(HA)的PCA植入体及喷涂HA的光滑金属表面植入体植入犬皮质骨后,分别于术后4、8及12周取出,通过X线摄片、不脱钙骨磨片、荧光显微镜、软X线摄片、骨计量学等方法对骨-植入体界面进行组织学和形态学的综合观察分析。结果各种植入体均具有良好的组织相容性。植入体表面复合BMP后,骨长入植入体界面的时间早于其它方法,新生骨组织成熟也较早。各时间段BMP复合PCA植入体组的新生骨形成率均较其它组高,但仅在4周时差异有显著性(P<0.05)。结论实验中采用的BMP与植入体的复合方法简单有效,BMP的应用可使骨与假体界面之间较早达到牢固固定。HA涂层方法能够促进骨组织长入及增强骨-植入体界面结合强度,并在中晚期有一定的优势,但是其喷涂工艺对固定效果有较大的影响,在假体的制造过程中应予以重视。     

钛-羟基磷灰石功能梯度材料骨结合强度的初步研究

目的从力学角度研究钛-羟基磷灰石功能梯度材料与骨组织的结合强度.方法将钛-羟基磷灰石功能梯度材料植入8只新西兰大耳白兔颅骨中,用同样规格的纯钛和纯羟基磷灰石作为对照.术后进行临床及X-ray观察、剪切强度及骨结合强度的测定.结果钛-羟基磷灰石功能梯度材料与骨结合界面的剪切强度均强于各个时期纯钛与骨结合界面的剪切强度(P＜0.05),在8周后强于纯羟基磷灰石与骨结合界面的剪切强度(0.01＜P＜0.05).结论钛-羟基磷灰石功能梯度材料具有良好的界面结合强度的特性,此材料可能具有较好的应用前景.     

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.     

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.     

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.