每次反复注水快速皮肤扩张法的实验研究

目的　探讨最佳的皮肤扩张法,了解每次反复注水快速皮肤扩张法的效果及机理。方法　白色乳猪4只,在脊柱两侧各设计3个皮瓣组,分别为每次反复注水快速扩张组、常规扩张组、对照组,在监测囊内压的情况下定期扩张,扩张结束后分别测定和比较扩张总面积、时间、皮肤的即时回缩率以及囊内压的变化,并进行组织学及超微结构的观察。结果　每次反复注水快速扩张组扩张后总面积明显大于常规扩张组（P＜0.05）,皮肤即时回缩率与常规扩张组间无明显差异（P＞0.05）,扩张总时间短于常规扩张组,扩张前囊内压在每次反复注水快速扩张组与常规扩张组间差异无显著性（P＞0.05）,每次反复注水快速扩张组扩张后皮肤的超微结构及功能与常规扩张组无明显区别。结论　每次反复注水快速皮肤扩张法是一种有效的、安全的方法,可在临床上推广应用。     

组织扩张术囊上皮肤来源、扩张率和回缩率研究

目的探讨恒压持续快速扩张的可行性。方法用白色小家猪１２只（１７．５±２．７１ｋｇ）、长方形硅胶扩张器（１８０ｍｌ）２４只作持续快速扩张术（ＣＴＥ）和常规间断扩张术（ＩＴＥ）对比研究。结果ＣＴＥ组６天完成扩张，ＩＴＥ组２７天完成扩张，两组扩张囊内平均实际液体量、扩张囊外皮肤总面积和皮肤回缩率相同（Ｐ＞０．０５）。ＣＴＥ组的皮肤净增面积和皮肤组织扩张率小于ＩＴＥ组（Ｐ＜０．０１）；ＣＴＥ组皮肤移行面积明显大于ＩＴＥ组（Ｐ＜０．０１）。结论恒压持续扩张术具有速度快的优势和某些与ＩＴＥ相似的性质，可用于局部皮肤病变或缺损的修复，但广泛性皮肤病的治疗仍应选择常规间断扩张术     

维持扩张期对扩张皮肤张力和即时回缩率影响的研究

目的：研究维持扩张期对扩张皮肤在体张力和即时回缩率的影响，并以此指导临床。方法：以狗为动物模型，在6只成年大狗的背侧，对称设计6个区域。实验分为注水2周组、6周组、实验对照组和空白对照组。分析比较各组的在体张力和即时回缩率（包括有包膜和去包膜）。结果：皮肤在体张力和即时回缩率随着维持期的延长逐渐缩小，而注水期的长短对其影响不大；去除包膜后皮肤的在体张力和即时回缩率明显降低。在此基础上，临床应用16例23个扩张器的效果较好。结论：在皮肤软组织扩张术中，可以通过缩短注水期（2周左右）、适当延长维持期（4周）以及去包膜的方法，可以达到减少扩张皮肤的在体张力和即时回缩率，增加扩张皮肤面积的目的。     

皮肤软组织快速扩张的实验研究

以白色乳猪为实验动物，分为常规扩张组，快速扩张组和对照组。在囊内压及皮肤血流的监测下定期扩张。扩张结束后分别进行皮肤血流动力学、物理学、组织学及超微结构的观察、测量。     

联合性快速皮肤软组织扩张法的研究

目的　观察联合性快速扩张法应用于皮肤软组织扩张术的效果 ,并探讨其机制。方法　在 8头小猪脊柱两侧设计 48块扩张区域 ,分为 :联合组 :耗时 1周。常规组 :耗时 3周。对照组分别测定扩张前囊内压 ;测量扩张毕皮肤表面积增加幅度、皮肤即时回缩率。结果　联合组扩张后皮肤即时回缩率 (3 6.2 3± 1.0 7) %与常规组 (3 5 .89± 0 .90 ) %比较 ,差异无显著性 (P >0 .0 5 ) ;与对照组相比 ,联合组表皮层厚度显著增厚 (P <0 .0 1) ,真皮层显著变薄 (P <0 .0 1) ,真皮层内胶原纤维密度明显减低 (P <0 .0 1)。结论　联合性快速扩张法能获得额外皮肤组织 ,对皮肤超微结构无明显影响 ,具有扩张速度快 ,并发症少的优点。     

转化生长因子β与皮肤创伤后瘢痕增生

转化生长因子β与皮肤创伤后瘢痕增生苏顺清综述辛时林审校皮肤损伤后胶原蛋白、纤连蛋白（ＦＮ）、氨基多聚糖（ＧＡＧ）等细胞外基质（ＥＣＭ）的异常沉积可形成增生性瘢痕和瘢痕疙瘩。在此过程中，许多细胞因子，如转化生长因子β（ＴＧＦ）、表皮生长因子（ＥＧＦ）、...     

bFGF和硫糖铝局部应用促组织扩张实验研究

目的：探讨bFGF和硫糖铝在持续恒压扩张术中局部应用的可行性。方法：以白色小家猪为实验动物,自身对照,分为3个实验和对照组,扩张同时分别注入bFGF加硫糖铝、bFGF、硫糖铝、生理盐水。扩张结束后第3天分别进行扩张器上总面积、皮肤净增面积、周围组织移行面积和皮肤即时回缩率的测量。结果：实验I组所获得的扩张皮肤面积、皮肤净增面积大于对照组（P＜0．05）;实验Ⅱ、Ⅲ组与对照组无统计学差别。结论：bFGF和硫糖铝用于持续恒压扩张术中,能有效地促进皮肤增殖扩展,扩张局部面积增加,皮肤即时回缩率降低,从而促进组织扩张。     

一次性软组织扩张的实验研究

为了探索一次性软组织扩张的可能性，应用激光多普勒微循环血流仪（ｌａｓｅｒｄｏｐｐｌｅｒｆｌｏｗｍｅｔｅｒ，ＬＤＦ），在９只健康雄性白色乳猪躯干部作一次性软组织扩张术（ｉｎｔｒａｏｐｅｒａｔｉｖｅｓｕｓｔａｉｎｅｄｌｉｍｉｔｅｄｅｘｐａｎｓｉｏｎ，ＩＳＬＥ），共对５４个ＩＳＬＥ扩张的皮肤进行微循环监测，同时对扩张囊内压力与ＩＳＬＥ皮肤血流的相关性及ＩＳＬＥ皮肤病理学变化进行了探讨。结果表明：一次性扩张的皮肤，其微循环灌注量显著高于对照组，可提供更多的额外皮肤。为临床应用一次性软组织扩张技术提供了实验依据     

皮肤软组织即时扩张术的临床应用

为探讨在确保治疗效果的前提下如何缩短疗程及减少并发症的发生，自１９９２年９月以来，将皮肤软组织即时扩张术分别用于颜面、胸前、前臂及背部因瘢痕、色素痣及血管瘤切除后皮肤软组织缺损创面的即时修复，共２５例，效果良好。对即时扩张术的手术方法、适应证和注意事项进行了讨论，认为在充分估计缺损区大小及即时回缩较重的情况下，即时扩张术不矢为修复小面积皮肤缺损的一种较好方法。     

皮肤扩张术后的组织退行性研究

目的 探讨扩张术对皮肤的损伤及退行性变作用。方法 选择常规间断扩张和持续恒压扩张术各9例，在扩张皮瓣术中切取标本组织病理学分子生物学及透射电子显微镜观察。结果 扩张可引起毛细血管出血，损伤修复纤维（网状纤维和弹力纤维）增生，微小动脉血栓形成，成纤维细胞凋亡增加，胶原纤维溶解。常规间断扩张后皮肤以退行性变为明显，持续恒压扩张后皮肤急性损伤明显。结论 扩张刺激可引起组织急性损伤和退行性变，提示常规扩张时间不能过长，持续扩张不宜过快。     

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 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.     

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.     

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.     

Is the recovery profile of mivacurium independent of the rate of decay of its plasma concentration in patients with normal plasma cholinesterase activity?

Background: The duration of action of muscle relaxants is poorly correlated to the rate of decay of their plasma concentration. The plasma concentration of mivacurium may rapidly decrease below its active concentration because of the extensive hydrolysis of mivacurium. By inflating a tourniquet on one upper limb for 3 min after the administration of atracurium, mivacurium or vecuronium, we studied the influence of the initial decline of their plasma concentration on their effect. Methods: In 50 patients anaesthetised with thiopental, isoflurane and fentanyl, the effect of bolus doses of 0.15 or 0.25 mg . kg^?1 mivacurium (MIV 15, MIV 25), 0.3 or 0.5 mg . kg^?1 atracurium (ATR 30, ATR 50) and 0.06 or 0.1 mg . kg^?1 vecuronium (VEC 06, VEC 10) were measured on both arms (evoked response of the adductor pollicis to train-of-four stimulation every 12 s), a tourniquet being applied on one arm just before and during 3 min after the muscle relaxant bolus. Results: Tourniquet inflation of 3 min almost abolished the neuromuscular effect of mivacurium. In the vecuronium groups and in the ATR 50 group, tourniquet inflation did not modify the maximum degree of depression of the twitch response. Also, the duration of action of vecuronium was unaffected by the tourniquet. In the ATR 30 group, times to return of the twitch response to 25% (duration 25%) and 75% (duration 75%) of control response were significantly shorter in the cuffed arm, 23 min vs 27 min, and 41 min vs 45 min, respectively. In the ATR 50 group, only duration 25% was significantly shorter in the cuffed arm (41 min vs 45 min). Conclusion: The results suggest that the rate of decline of the plasma concentration of mivacurium is so rapid, that a very low and almost clinically ineffective concentration is present as soon as 3 min after its administration. The results also indicate that the recovery from a mivacurium-induced neuromuscular blockade is not influenced by the rate of decay of its plasma concentration in patients with genotypically normal plasma cholinesterase.     

Membranes in Artificial Organs

Abstract: Membrane processes play a pivotal and enabling role in modern replacement therapy for acute and chronic organ failure and in the management of immunologic diseases. In fact, virtually all contemporary extracorporeal blood purification methods employ membrane devices, and the next generation of artificial organs and tissue engineering therapies are almost certain to be similarly grounded in membrane technology. In this short essay, we comment on the similarities and differences among synthetic membranes and their natural counterparts and also provide a critical overview of the demographics and technology of hemodialysis, hemofiltration, apheresis, oxygenation, and emerging membrane technologies and applications.     

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.