产胆固醇氧化酶重组大肠杆菌的发酵培养基和诱导条件的优化

在摇瓶中对产胆固醇氧化酶重组大肠杆菌的发酵培养基和诱导条件进行了优化,优化培养基为甘油10 g/L,胰蛋白胨10 g/L,酵母粉5 g/L,KH2PO4 2 g/L,K2HPO4 4 g/L,Na2HPO4·12H2O 7 g/L,(NH4)2SO4 1.2 g/L,NH4Cl 0.2 g/L,MgSO4·7H2O 1 g/L;优化的诱导条件为:对数生长中期诱导,IPTG浓度为0.3 mmol/L.在优化的培养基和优化的诱导条件下,单位菌体产酶量达745.86 U/g,菌体产酶水平达1 625.97 U/L,为优化前的700 U/L的2.3倍.     

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℃.     

粗状假丝酵母(Candida valida T2)生产脂肪酶的发酵条件

对粗状假丝酵母产生脂肪酶的培养条件进行了研究。结果表明,该菌株产脂肪酶的适宜培养基组成为:桐油15mL/L,黄豆粉30g/L,糊精10g/L,硝酸铵10g/L,MgSO4·7H2O1g/L,K2HPO42g/L,Tween800.5g/L;最佳培养为温度30℃、发酵液起始pH6,摇瓶发酵脂肪酶活力达到1467U/mL。     

鸡腿蘑菌株筛选及深层发酵培养基的优化

对4个鸡腿蘑菌株进行了发酵筛选,选出生物量较高的菌株农林鸡腿蘑(NL),并通过单因素试验,确定玉米粉、蔗糖为碳源,麸皮为氮源;在此基础上,以筛选的碳源、氮源和无机盐KH2PO4和MgSO4·7H2O为考察因素,以生物量为主要指标利用正交试验优化培养基配方比例,确定鸡腿蘑摇瓶发酵培养基最佳配方为:玉米粉 4 g/dL,蔗糖 2 g/dL,麸皮 4 g/dL,KH2 PO4 0.1g/dL,MgSO4·7H2O 0.1 g/dL.     

一株碱性低温脂肪酶产生菌发酵条件的优化

通过单因素实验,对SYBC Wu-3菌摇床发酵产脂肪酶的培养基组成和培养条件进行优化,得出较佳的产酶培养基组成配方为:蛋白胨5 g/L,酵母膏 6 g/L,NaH2PO4 3 g/L; 油脂250 mL/L,乳化剂OP 25 mL/L.最优发酵条件为250 mL的摇瓶装液量50 mL,培养温度30 ℃,发酵时间72 h.经过优化后发酵液脂肪酶酶活力最高可达到10.68 U/mL,较优化前提高了2.8倍.     

聚γ-谷氨酸高产突变株的选育及摇瓶发酵条件

对地衣芽孢杆菌(Bacilluslicheniformis)进行亚硝基胍和60Co诱变,获得一株γ PGA的高产菌株C9.γ PGA质量浓度由9.44g/L提高到19.76g/L,提高了109%.突变株传代10次,质量浓度保持基本稳定.通过正交试验和单因素试验对发酵培养基及发酵条件进行了优化.当发酵培养基中含柠檬酸12g/L、甘油80g/L、L 谷氨酸23g/L、氯化铵7g/L,pH7.0,装液量为50mL/250mL三角瓶,接种体积分数为5%时,37℃摇瓶发酵72h,γ PGA达到23.32g/L.     

褐环乳牛肝菌发酵条件的优化

研究了褐环乳牛肝菌(Suillus luteus)发酵的营养条件及环境条件.在单因素实验优化的基础上,进一步采用正交实验对麦芽汁、酵母膏、装液量和接种量进行了研究.单因素实验及正交实验优化后得到褐环乳牛肝菌液体发酵的适宜培养基组成为:麦芽汁270 mL/L,酵母膏6.7 g/L,KH2PO4 0.25 g/L、MgSO4·7H2O 0.3 g/L、CaCl2·2H2O 0.19 g/L、FeCl3 48 mg /L、柠檬酸0.1 g/L、VB1 2 mg/L.在装液量为100 mL/500 mL、接种体积分数10%,初始pH值5.5～6.5,转速150 r/min的条件下,最终菌体量达12.0 g/L,比优化前提高了40.19 %.在小型发酵罐上研究了pH和溶氧对菌体生长的影响,pH值恒定在5.5时要优于自然pH值下的情况,而逐渐提高转速使溶氧保持在20%以上要优于较高转速下的供氧模式.     

圆弧青霉PG37碱性脂肪酶的发酵工艺条件

研究了圆弧青霉PG3 7碱性脂肪酶的发酵工艺条件 ,优化了PG3 7的摇瓶最适产酶条件 .其中 ,发酵培养基的组成为 (g/dL) :豆饼粉 3 .0 ,玉米浆 3 .0 ,磷酸氢二钾 1 .0 ,硫酸镁 0 .1 ,大豆磷脂0 .5,柠檬酸钠 0 .0 5,花生油 0 .2 ;发酵培养基起始 pH 7.5,发酵温度 (2 9± 1 )℃ ,摇床转速 2 50r/min ,发酵周期 96h ,发酵期间于 3 6,54,72h分别流加 0 .4 g/dL花生油 .在此条件下 ,PG3 7的脂肪酶产率为 2 0 60 μmol/ (min·mL) .PG3 7在 2 5L的实验室小罐中的产酶水平为 1 90 0 μmol/ (min·mL) .     

黑曲霉VVTP84生产果糖转移酶

从产果糖转移酶的 11株菌株中筛选出一株黑曲霉VVTP84菌 .该菌株在含蔗糖的培养基中 ,最佳摇瓶发酵时间为 30h ,pH值为 7.0 ;当蔗糖质量浓度在 2 5 0g/L以内时 ,产酶与蔗糖质量浓度呈正相关 ;MgSO4 ·7H2 O和KH2 PO4 的添加量分别以控制在 1.5 g/L和 1.0 g/L为宜     

促进剂对发酵生产碱性果胶酸裂解酶的影响

为制取适用于纺织用碱性果胶酶,必须得到高酶活的发酵液.通过促进剂的单因素试验及正交试验,对BacillussubtilisWSH02-02产生碱性果胶酸裂解酶的摇瓶发酵条件进行了优化.优化后该菌株产酶活比对照提高了30%,所采用的促进剂优化组合为:Tween 603g/L,CaCO37g/L,MgSO4·7H2O4g/L.     

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.     

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.     

Immunomodulation in Transplantation with Photopheresis

Abstract: Photopheresis is a technique in which peripheral blood mononuclear cells, in the presence of a photoacti-vatable compound, are exposed extracorporeally to ultraviolet A light and reinfused, inducing a host autoregula-tory immune response. Experimental work and ongoing clinical studies are helping to define the role of this novel, safe, and non-toxic immunomodulating technology in the field of transplantation.