产β-葡聚糖酶淀粉液化芽孢杆菌的选育

通过对一株淀粉液化芽孢杆菌进行紫外和^60Co逐级诱变，使该菌株产β-葡聚糖酶酶活从80U／mL提高到105U／mL；对突变株进行多次单菌落分离及传代，对其传代稳定性的研究表明：该菌株产酶性能稳定；在5L发酵罐中突变株的产酶水平比摇瓶要高，可达120U／mL，产酶周期比摇瓶缩短了15h．     

Thermobifida fusca WSH03-11突变株合成角质酶的发酵条件

以放线菌Thermobifida fusca WSH03—11——高产角质酶突变株为出发菌株，在摇瓶中考察了碳、氮源等条件以及接种量、装液量和初始pH值等环境条件对突变株细胞生长和产角质酶的影响。通过优化发酵条件，突变菌株的角质酶酶活达10．1U／mL，提高了15％。在此基础上，在5L发酵罐中进一步研究了碳源流加对突变株发酵产酶的影响，结果发现，分别在0、24、48h添加1％乙醇，角质酶酶活达到16．4U／mL，细胞干重（DCW）达到3．7g／L，而且发酵时间也由110h缩短到50h。     

带自身启动子的6gαB基因在枯草芽孢杆菌中的表达

将来源于嗜热脂肪芽孢杆菌的启动子连同β半乳糖苷酶bgαB基因经PCR扩增后，连接在T载体上，再取代枯草杆菌载体pZ01-bgaB的启动子，将其在枯草杆菌宿主WB600中表达．经摇瓶发酵20h，得到乳糖酶活力6．37U／mL，比活力3．814U／mg，SDS—PAGE电泳显示有明显重组蛋白质条带．证明了嗜热脂肪芽孢杆菌来源的启动子在枯草杆菌中是完全适用的．     

产过氧化氢酶菌株培养条件的优化

通过对溶壁微球菌培养基优化,确定最佳发酵培养基,并对发酵工艺条件进行了初步的优化.最适碳源是麦芽糖,最适氮源是蛋白胨和酵母膏,最近无机盐是MnSO4;该菌株产酶的最佳培养基配方为:60 g麦芽糖,13 g蛋白胨,8 g酵母膏,1 g MnSO4,5 g NaCl,2 g NaH2 PO4·2H2O,2 g K2HPO4·3H2O,0.5 g MgSO4·7H2O,0.5 g CaCl2,1 000 mL水.从该菌株发酵过程曲线发现,该菌株大量产酶期在12-14 h.摇瓶发酵最适初始pH值为7.0,250 mL三角瓶装液量为25mL,接种体积分数为5%,培养温度为37℃.     

Penicillium sp.X-1液态发酵生产生淀粉酶的优化

通过摇瓶发酵,研究了培养基成分对Penicillium sp.X-1液态发酵产生淀粉酶的影响。结果表明：碳源、氮源及MgCl2对产酶有较大的影响,经响应面优化得到的培养基组成为：玉米粉42 g/L,豆饼粉30 g/L,MgCl216 mmol/L,在最优条件下酶活达到239 U/mL,与采用基本培养基的相比,酶活提高了7.5倍.     

耐热过氧化氢酶基因工程菌的构建及其发酵条件

利用PCR扩增技术以嗜热脂肪芽孢杆菌IAM11001染色体DNA为模板，扩增得到嗜热脂肪芽孢杆菌过氧化氢酶编码基因perA。再与经EcoRⅠ酶切的温控表达载体pBV220连接，构建重组质粒，并转化宿主大肠杆菌JM109，得到耐热过氧化氢酶基因工程菌，然后对该工程菌在LB培养基和半合成培养基中的发酵条件进行了优化。结果表明：在LB培养基中，诱导时期和酶合成最佳诱导时间均为5h，最大产酶量达到72．9U／mL；在半合成培养基中，于30℃培养4h，再于42℃诱导培养6h，产酶量最高达到131U／mL。     

培养基及培养条件对普鲁兰酶的影响

从土壤中分离出一株产普鲁兰酶的菌株,初步鉴定为芽孢杆菌．通过优化发酵培养基及发酵培养条件,在２５０ｍＬ的摇瓶中可达到４．５μｍｏｌ／（ｍｉｎ·ｍＬ）的普鲁兰酶酶活．优化后的发酵培养基成分如下：玉米支链淀粉２ｇ／ｄＬ,蛋白胨２ｇ／ｄＬ,牛肉膏１．５ｇ／ｄＬ,ＮａＣｌ０．５ｇ／ｄＬ,ＭｎＳＯ４２μｍｏｌ／Ｌ．摇瓶发酵工艺条件：接种量１７％,温度３７℃,摇瓶转速２２０ｒ／ｍｉｎ,ｐＨ６．０,发酵周期３２ｈ．通过２Ｌ容积的发酵罐批式发酵,酶活可稳定在３．３μｍｏｌ／（ｍｉｎ·ｍＬ）左右     

乳酸菌SK1.002产L-阿拉伯糖异构酶培养基优化及发酵条件

L-阿拉伯糖异构酶能将D-半乳糖异构成D-塔格糖。通过单因素试验和快速登高法对乳酸菌SK1.002产L-阿拉伯糖异构酶的培养基进行优化,确定发酵优化条件为（组分g/L）：麦芽糊精28,酵母膏10,玉米粉浆22,无水乙酸钠10,K3PO40.2,NaCl 0.01,FeSO4.7H2O 0.01,Mg-SO4.7H2O 0.2,MnSO4.2H2O 0.05,L-阿拉伯糖2.5。发酵初始pH 8.4,培养温度37℃,接种体积分数3%,培养时间12 h。在此发酵条件下,酶活达到了7.28 U/mL。     

发酵生产谷氨酰胺转胺酶的摇瓶条件

在摇瓶条件下， 以淀粉为碳源，蛋白胨及酵母膏为氮源，对Ｓｔｒｅｐｔｏｖｅｒｔｉｃｉｌｌｉｕｍｍ ｏｂａｒａｅｎｓｅ生产谷氨酰胺转胺酶（ＭＴＧ）的摇瓶发酵条件进行了探索．研究结果表明，发酵法生产谷氨酰转胺酶的适宜初始ｐＨ 值、淀粉质量浓度、接种量分别为６．１，２ ｇ／ｄＬ，１０％ ；ＭＴＧ酶活最高可达１．８３ ｕｍ ｏｌ／（ｍ ｉｎ·ｍ Ｌ）．初始加入硫酸铵对菌体生长影响不大，但对ＭＴＧ 的合成却产生抑制作用；初始加入纯氨基酸及胱氨酸母液不利于ＭＴＧ 酶活的提高．     

正交旋转回归试验优化纤维素酶发酵培养基

利用旋转回归法研究里氏木霉WX-112发酵生产纤维素酶的两个重要因素：微晶纤维素粉（Avicel）和麸皮对滤纸酶活的影响，并拟合出回归方程。经回归分析表明，培养基中Avicel、麸皮的含量及其配比对滤纸酶活有显著影响。通过岭脊分析寻优得出：Avicel最佳浓度为1．34g／dL、麸皮最佳浓度为3．35g／dL，在此优化条件下滤纸酶活可迭6．51U／mL。用30L发酵罐进行放大试验，滤纸酶涪可达10．84U／mL，CMCase达到449．57U／mL。     

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.     

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.     

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.     

Dilemma of Membrane Biocompatibility and Reuse

Abstract: Numerous articles have been published on the multiple use of dialyzers and on the effect of different reprocessing chemicals and techniques on the dialyzer biocompatibility and performance. The results often appear contradictory, especially those comparing standard biocompatibility parameters. Despite this confusion, a discerning review of the published works allows certain limited conclusions to be drawn. Reprocessing of used hemodialyzers changes the biocompatibility profile of a dialyzer as defined by the parameters complement activation. leukopenia, and cytokine release. The effect of reprocessing depends on the chemicals and reprocessing technique applied and also on the type of membrane polymer being subjected to the reprocessing procedure. Reports of pyrogenic reactions indicate that the flux of the membrane also influences how suitable it is for safe reuse. An increased risk of allergic and pyrogenic reactions appears to be associated with dialyzer reuse. Furthermore, there has been a lack of investigations into the immunologic effect of the layer of adsorbed and chemically altered proteins that remains on the inner surface of reprocessed dialyzers. We conclude that the clinical benefit of dialyzer reuse cannot be generally accepted from a biocompatibility point of view.