多孔型种植体磷酸钙溶胶膜-骨界面的远期观察

目的进一步探讨磷酸钙（CaP）溶胶薄膜对多孔型钛合金（Ti-6Al-4V）种植体表面骨生长的远期影响。方法将表面涂有极薄CaP溶胶膜的多孔型钛合金种植体分别植入8只兔的胫骨。种植区愈合第2周、8周、12周、24周后，各取含种植体的骨组织标本，利用反向扫描电镜摄像技术进行形态观测研究。结果术后第2周SEM显示骨组织直接沿磷酸钙溶胶膜表面生长，而且磷酸钙溶胶膜在种植体表面附着良好；术后第8周与第12周，SEM高倍镜下所见相似，在种植体表面磷酸钙溶胶膜与新生骨组织之间形成富含大量钙和磷酸盐的黏合线样层；术后第24周，种植体表面大部分金属颗粒上的磷酸钙溶胶膜已消失，新生骨组织直接附着在钛合金种植体表面。结论远期观察多孔型种植体表面的磷酸钙溶胶膜，未见涂层界面分离现象。磷酸钙溶胶膜不仅有利于促进种植体早期骨结合，而且即使涂层被吸收后也不会影响种植体的稳固性。     

等离子喷涂硅灰石涂层种植体体内植入的实验研究

目的对硅灰石（CaSiO3）涂层的生物学性能进行评价,为临床选择种植体表面改性方法提供实验依据。方法在纯钛棒表面采用等离子喷涂的方法分别加涂CaSiO3涂层和羟基磷灰石（HA）涂层,切割成直径3mm、高12mm的圆柱状植入体各12枚,植入实验狗的下颌骨内,检测种植体-骨界面的结合强度,并用扫描电镜进行形态观测。结果植入3个月后,CaSiO3涂层种植体-骨界面的剪切结合强度高于HA涂层种植体-骨界面的剪切结合强度,二者之间有显著差异（P〈0．05）。结论CaSiO3涂层具有良好的生物活性,是一种较有应用前途的种植体涂层材料。     

比格犬体内涂层螺钉-骨组织界面的组织学观察

目的了解钛涂层、羟基磷灰石(hydroxyapatite,HA)涂层及钛+HA复合涂层螺钉置入体内后,螺钉-骨界面在术后早期的骨整合情况。方法选取成年比格犬16只平均分为普通螺钉组、HA涂层螺钉组、钛涂层螺钉组及钛+HA复合涂层螺钉组(每组4只,雌雄各2只)。螺钉置入比格犬颈椎椎体3个月,之后取出椎体,进行脱水、包埋处理,进行硬组织切片染色,观察涂层-骨界面的骨整合情况。结果 HA涂层螺钉和钛+HA复合涂层螺钉与周围骨组织结合紧密,骨组织的接触率明显高于普通螺钉和钛涂层螺钉,其中HA涂层螺钉与周围骨组织的接触率最高。结论HA涂层螺钉与周围骨组织的接触率最高,这可以作为生物力学测试中HA涂层螺钉具有较高生物力学稳定性的界面组织学基础。     

HA梯度涂层复合BMP人工股骨柄的研究

目的研究新型HA梯度涂层人工股骨柄假体及其复合重组人骨形态发生蛋白-2(rhBMP-2)后的界面生物学特征。方法将15只健康成年杂交犬随机分成三组,行右侧人工股骨头置换,分别植入钛合金人工股骨柄(Ti组)、HA涂层钛合金人工股骨柄(HA组)和复合rhBMP-2的HA涂层钛合金人工股骨柄(BMP-HA组),12周后处死动物,取有植入假体的股骨上段进行X线检查和界面组织学观察,处死前肌内注射盐酸四环素行荧光标记。结果X线检查显示Ti组中有1例假体周围出现局部透亮带。HA组及BMP-HA组股骨柄假体周围可见新骨形成。光镜下新型HA梯度涂层无明显降解和碎裂,性质稳定。Ti组、HA组和BMP-HA组界面骨结合率分别为4.05%±7.66%、71.04%±9.81%和88.86%±6.56%。显示HA组和BMP-HA组界面骨结合良好,骨结合率显著高于Ti组(P<0.01),BMP-HA组界面骨结合率也显著高于HA组(P<0.01)。BMP-HA组的界面有较强的四环素荧光标记,显示界面成骨活跃。结论新型HA梯度涂层假体可引导骨组织长入涂层,与骨组织结合良好,结合率高,能增加假体的稳定性。该涂层可复合rhBMP-2发挥协同作用,明显增加涂层假体的骨整合,有望成为可供临床使用的新型涂层假体。     

犬骨形态发生蛋白/羟基磷灰石梯度涂层骨的结合性能

目的探讨复合重组人骨形态发生蛋白(rhBMP)的羟基磷灰石(HA)梯度涂层植入体的界面骨结合性能。方法6只健康成年杂交犬股骨内、外髁关节面各垂直植入1个种植体,共植入钛合金圆柱体(Ti组)、HA涂层钛合金圆柱体(HA组)、复合rhBMP的HA涂层钛合金圆柱体(BMP组)各8个。12周时取材进行界面组织学观察、顶出试验和扫描电镜检查。结果界面组织学和扫描电镜观察显示HA组和BMP组界面骨结合良好。Ti组、HA组和BMP组骨结合率分别为(11.53±10.79)%、(81.51±4.53)%、(92.71±5.30)%(P<0.01);抗剪切力强度分别为(2.36±1.04)、(21.65±1.48)、(30.95±3.67)Mpa(P<0.01)。结论复合BMP的HA梯度涂层在负重情况下界面骨结合好,结合强度高,已具备应用于新型涂层假体研制的生物学性能。     

纯钛种植体-骨界面的高分辨透射电镜及电子衍射观察

目的探明高分辨透射电镜(HVTEM)下纯钛种植体-骨界面的结合形貌及钛-骨组织的电子衍射表现。方法采用低温离子减薄制片技术,用 Phlips EM-430和 X 射线双晶衍射仪进行观察分析。结果界面上大小不一高电子密度的钙球或一片钙化骨组织与钛融合为一体。钛周围骨组织是呈双向性生长。结论钛-骨结合十分紧密,没有间隙。文中对钛-骨结合形式及影响骨整合的因素进行了进一步探讨。     

复方丹参对种植体骨整合影响的研究现状与展望

复方丹参为临床常用药,有抗心肌缺血,扩冠状动脉,抗心律失常等作用;近期姬洪全等发现复方丹参可以促进家兔骨折中期骨愈合,通过免疫组化显示,在骨折愈合的中期,复方丹参可以促进TGF-β1的表达,提示其可能是通过增加TGF-β1的表达而促进家兔骨折中期骨愈合;种植体一骨界面骨整合的获得是种植体成功的关键,对于骨结合的过程有多种因子参与,其中TGF-β1发挥着重的作用;通过家兔实验,设时照组,进行不同层次观察,证实复方丹参是否对植体一骨界面骨整合有影响.     

晚期糖基化终末产物及受体在实验性2型糖尿病大鼠种植体周围的变化及表达

目的 建立2型糖尿病大鼠动物模型,探讨晚期糖基化终末产物及其受体在实验性2型糖尿病大鼠种植体骨整合过程中的变化及表达.方法 45只3个月龄SD健康雄性大鼠,将大鼠随机分为糖尿病模型组25只和正常对照组20只.首先建立2型糖尿病大鼠模型,建模成功后将模型大鼠随机分为DM组和DM种植组,每组10只.将20只正常组大鼠随机分为正常对照组和正常种植组,每组10只.分别于正常种植组和DM种植组的胫骨近骺端植入纯钛种植体,植入10周后于下腔静脉采血,保存所采集标本,用RF-5301PC型荧光分光光度计测定血清中AGEs含量的变化.硬组织标本采用不带种植体脱钙切片,以正常组为对照,HE染色后用免疫组织化学方法检测种植体周围RAGE的表达.结果 10周后,DM种植组和DM组与正常对照组和正常种植组相比,血清中AGEs的变化差异有统计学意义（P ＜0.05）,正常种植组和DM种植组与正常对照组的种植体周围骨组织RAGE表达比较,差异均有统计学意义（P ＜0.05）;DM种植组与DM组比较,差异亦有统计学意义（P ＜0.05）.结论 种植体骨组织愈合过程中AGEs和RAGE相互作用是影响2型糖尿病种植体骨结合的机制之一.     

假体周围骨溶解性骨缺损的转骨形态发生蛋白-2基因治疗

目的 模拟假体周围骨溶解环境,观察骨形态发生蛋白-2(BMP-2)基因治疗假体周围骨溶解性骨缺损的效果.方法 成年雄性Beagle犬6条,于股骨外髁造成假体周围3mm骨缺损区.1条动物的左侧缺损区植入1ml平均直径1μm的钛合金颗粒混悬液,右侧植入1ml磷酸盐缓冲液(PBS),观察造模结果;其他5条动物双侧植入1ml钛合金颗粒混悬液,于术后2个月取出假体,植入转BMP-2基因冻干骨或单纯冻干骨,二次术后3个月取材,行组织学、组织形态计量学观察植骨愈合替代及界面骨整合情况.结果 颗粒造模术后2个月可见典型的骨溶解界膜组织形成.翻修术后3个月,冻干骨组见较多植骨残余,假体-骨界面基本为软组织界膜,假体骨接触率(BIC)为(1.38±1.22)%;基因治疗组见少量植骨残余,假体-骨界面有点状骨接触,BIC为(12.96±1.61)%,两组差异有统计学意义(P<0.01).结论 采用BMP-2基因治疗可提高假体周围骨溶解性骨缺损的界面骨整合.     

纯钛种植体—骨界面的飞行时间二次离子质谱分析

为探明纯钛与骨组织间的相互作用与结合机理，采用荧光显微镜及先进的飞行时间二次离子质谱分析仪，对已形成骨整合的１，３及６个月钛—骨结合界面进行了分析和测试。结果表明，纯钛种植体与骨结合十分紧密；钛与骨组织间的离子作用是相互的；钛—骨间既存在物理性结合，也存在化学性结合。钛离子向组织内有扩散，但扩散的量极微，扩散的深度可达１００μｍ以上；钛离子的扩散在植入骨组织后早期（１个月～３个月）较多，以后较少。钛离子向组织内沥出的同时，组织内Ｃａ＋、ＯＨ－、Ｏ－等离子向钛氧化膜内也有渗透。对纯钛种植体周围骨组织的生长方式观察，证明呈双向性生长，一种是骨组织从邻近或远离种植体的骨床向种植体表面生长；另一种是新骨组织直接沉积在种植体表面并向骨床生长。研究根据纯钛种植体与骨组织间的离子分布、渗透等情况，从分子、原子水平进一步对钛与骨组织的相互作用及结合机理进行了探讨。     

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.