动物NECM的稳定性评价

“动物ＮＥＣＭ的制作”文章发表近半年，已制作好的动物皮肤、肌腱、软骨和骨的ＮＥＣＭ已在保存液中保存了１３个月，为了观察ＮＥＣＭ和保存液的稳定性，本文做了如下几个方面的研究：（１）保存液：未放置ＮＥＣＭ新配制的和已放置１年的保存液；放置ＮＥＣＭ的保存液（１９９７年２月）。上述保存液均细菌培养，镜下观察和成分分析。（２）电镜和组织学光镜观察；１９９７年和２月制作的ＮＥＣＭ的光镜观察；放置１３个月后的Ｎ     

组织工程学研究中偏光显微镜的应用

偏光显微镜是地质界用来观察晶体矿物的重要仪器，其理论基础是结晶光学，特点是即可观察结构，又可根据光学性质（折光率值不同）来判断成分，通过在研究ＮＥＣＭ和注射性胶原制作的过程中，用偏光显微镜和光镜观察同一部位的组织片，加以对比分析。因为胶原是生物体内的特殊“晶体”，故认为偏光显微镜应用在组织工程研究中，不仅开阔了观察领域，而且是重要的观测手段和方法。用偏光显微镜观察了猪骨ＥＣＭ胶原框架，以及注射性胶     

组织工程学研究中偏光显微镜的应用

偏光显微镜是地质界用来观察晶体矿物的重要仪器。其理论基础是结晶光学，特点是即可观察结构，又可根据光学性质（折光率值不同）来判断成分。通过在研究ＮＥＣＭ和注射性胶原制作的过程中，用偏光显微镜和光镜观察同一部位的组织片，加以对比分析。因为胶原是生物体内的特殊“晶体”，故认为偏光显微镜应用在组织工程研究中，不仅开阔了观察领域，而且是重要的观测手段和方法。用偏光显微镜观察了猪骨ＥＣＭ胶原框架，以及注射性胶原制作过程中胶原变化特点。认为本方法简单不需染色，并可特异的观察到胶原的分布和走行。     

长征－1号多器官保存液对兔肾脏冷冻保存的连续形态学观察

自１９９２年始研制成功长征－１号多器官保存液（简称ＣＺ－１液）。在完成对兔心脏及肝脏的冷冻保存后的形态学变化观察后，又做了对兔肾脏冷冻保存的形态学改变观察，并与ＵＷ液和ＨＣ－Ａ液作了比较。结果表明：冷冻保存７２小时以内ＣＺ－１液组肾脏组织光镜和电镜下形态学改变与ＵＷ组相比无明显区别，而且ＣＺ－１液组冷冻保存肾脏组织的变化以及细胞和细胞器的变性均缓于ＨＣ－Ａ组。由于ＨＣ－Ａ液已被证实能有效地保存犬肾在７２小时内，临床保存供肾在５７小时以内，ＵＷ液已经被证实能有效地保存供肾在７２小时以内，因此认为：从光镜和电镜下肾脏组织观察来看，ＣＺ－１液能保存兔肾脏在７２小时之内。     

动物皮肤、肌腱、软骨和骨的ECM制作

细胞外基质（ＥＣＭ）研究是组织工程学的重要部分，即是重要基础研究内容，又是研究细胞外基质的替代物课题。针对目前临床上大量应用人工合成的ＥＣＭ存在的问题（炎性反应、排斥反应、相容性等），本研究试图用动物的组织（自然的）ＥＣＭ替代人工合成的ＥＣＭ。用组织工程学方法处理动物组织，获得的产物经ＨＥ、奥新蓝染色、光镜观察和不染色切片偏光显微镜观察，证实经处理后的动物组织ＥＣＭ仅剩下肌腱、皮肤、软骨和骨的胶原框架。     

动物皮肤,肌腱,软骨和骨的ECM制作

细胞外基质研究是组织工程学的重要部分，即是重要基础研究内容，又是研究细胞外基质的替代物课题。针对目前临床上大量应用人工合成的ＥＣＭ存在的问题（炎性反应，排斥反应、相容性等），本研究试图用动物的组织（自然的）ＥＣＭ替代人工合成的ＥＣＭ。用组织工程学方法处理动物组织，获得的产物经ＨＥ、奥新蓝染色、光镜观察和不染色切片偏光显微镜观察，证实经处理后的动物ＥＣＭ仅剩下肌腱、皮肤、软骨和骨的胶原框架。     

CO_2激光除皱机理的实验研究

应用超脉冲ＣＯ２激光对新西兰兔进行皮肤除皱术，术后进行活体、光镜及电镜观察。结果显示，ＣＯ２激光除皱主要作用于皮肤表皮及真皮浅层，造成表皮细胞层全部或部分脱落，真皮浅层胶原纤维变性。新生的表皮皱褶变浅、减少，新生的胶原纤维富有弹性，使皮肤绷紧，去除细小皱纹。实验观察超脉冲ＣＯ２激光对毛发生长具有刺激作用     

化学处理的冻干异体肌腱移植的实验研究

目的：用化学及冷冻干燥方法处理鸡趾屈深肌腱，选择性地去除其腱细胞成分而不破坏其胶原纤维，以建立一种能显著降低肌腱抗原性，而不明显损伤肌腱强度的异体肌腱处理技术。方法：用１∶１三氯甲烷／甲醇（ＣＭ）混合液及含碘乙酸、乙二胺四乙酸、叠氮钠的转移液浸泡肌腱后，－４℃下真空冷冻干燥。用ＣＭ处理的冻干肌腱作同种异体移植，同时以新鲜异体及自体肌腱移植作对照。结果：羟脯氨酸含量测定、生物力学分析、大体、显微及超微观察显示：ＣＭ处理的异体移植肌腱与自体移植腱结果相似，而未处理异体移植肌腱则被排斥。ＣＭ处理的异体移植腱形成完全由细胶原原纤维（直径３３．３ｎｍ）组成的新生移植腱，而对照组自体移植腱含少量原粗大胶原原纤维（直径３１７．０ｎｍ）。结论：化学处理的冻干异体肌腱是一种良好的自体组织替代材料     

CO2激光除皱机理的实验研究

应用超脉冲ＣＯ２激光对新西兰兔进行皮肤除皱术，术后进行活体、光镜及电镜观察。结果显示，ＣＯ２激光除皱主要作用于皮肤表皮及真皮浅层，造成表皮细胞层全部或部分脱落。真皮浅层胶原纤维变性。新生的表皮皱褶变浅、减少、新生的胶原纤维富有弹性，使皮肤绷紧，去除细小皱纹。实验观察超脉冲ＣＯ２激光对毛发生长具有刺激作用。     

从NECM制取的可注射性胶原的生物学评价

从ＮＥＣＭ制取可注射胶原是从大分子降解为胶原分子，因此不需要交联剂和稳定剂。溶液中仅有胶原分子、无交联剂。本实验是将可注射胶原液注入大鼠尾部皮下组织内，共注射３０只，分三批杀死（１．５个月，３．０个月和半年），取注射部位的皮下组织作组织切片，染色（ＨＥ）、光镜观察（包括偏光显微镜）。     

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.     

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.     

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.