核黄素产生菌的补料发酵

通过分析核黄素产生菌E .ashbyii在发酵过程中菌体量、糖质量浓度、pH值、核黄素质量浓度和粘度的变化及菌体形态与核黄素生物合成之间的联系 ,发现 pH值对菌体生长有显著的影响 ,菌体浓度过高会导致发酵液粘度过大 ,通风供氧困难 ,菌体活力下降 .采用先低浓度培养菌体 ,然后根据发酵液 pH值的变化进行多次适量补料 ,不仅可以控制菌体的过度增殖 ,缓解通风供氧不足造成的困难 ,而且还可以保持菌体活力 ,增加核黄素的产量 .     

玉米原料细菌酒精发酵的研究

对运动发酵单胞菌ＺｙｍｏｍｏｎａｓｍｏｂｉｌｉｓＡＴＣＣ３１８２１的试验表明：该菌株最适发酵糖浓度为１５０～２００ｇ／Ｌ，ｐＨ为７左右。以玉米粉为原料，该菌株在发酵速率及淀粉出酒率等方面均比Ｋ字酵母优越。玉米粉在糖化３０ｍｉｎ，添加ＣＡＸ２０ｇ／Ｌ３５℃发酵４０ｈ后，酒精度达７２ｇ／Ｌ残糖（还原糖）４．２ｇ／Ｌ淀粉利用率９１．５％；淀粉出酒率４８．５％（按无水酒精计）。     

从发酵液中分离提取核黄素

核黄素的溶解度受溶液的ｐＨ值影响较大，在碱性条件下核黄素的溶解度较大，而在偏酸性溶液中溶解度较小。实验中分析了温度、ｐＨ值、作用时间和避光条件等因素对核黄素分解损失的影响，在此基础上设计了碱溶法提取核黄素的新工艺，并用核黄素的发酵液进行了试验，获得了较好的效果。与传统的酸溶法提取工艺相比，不仅提高了收得率，能耗也大大降低。     

发酵法制核黄素

以实验用Ｅ．ａｓｈｂｙｉＡｓ２．４８１为对象，研究了菌种特性，并对发酵培养基配方及摇瓶工艺条件进行了优化。研究结果：发酵培养基以葡萄糖、蛋白胨、玉米浆为主要原料；发酵起始ＰＨ＝６．８；５００ｍｌ和２５０ｍｌ三角瓶最佳装液量分别是６０～７０ｍｌ和２０～３０ｍｌ；接种量为１０％，在振动次数１００ｒ／ｍｉｎ，振幅８～１０ｃｍ的摇床上进行摇瓶。以豆油或油酸钠为促生因子，核黄素产量从０．１ｇ／Ｌ提高到０．６ｇ／Ｌ．     

同化淀粉能力强的酵母菌Y-9601株生物学特征鉴定及其应用

对从土壤中筛选到的酵母菌Ｙ－９６０１ 株进行了形态培养特征及生理生长特性的研究．该菌株以多边芽殖方式进行无性繁殖，形成子囊孢子．在无维生素培养基上不生长．同化和发酵萄葡糖、半乳糖、蔗糖、麦芽糖、１／３ 棉子糖，不同化乳糖及硝酸钾．同化淀粉、纤维二糖及Ｄ－木糖能力强，对淀粉具有较强的酒精发酵能力，鉴定为酵母属糖化酵母种．其最适生长温度为３０～３４ ℃，最适生长ｐＨ 值为５．０～６．０，在麦芽汁中液体培养倍增时间为９０ ｍ ｉｎ．     

溶氧控制和pH控制在赖氨酸分批发酵过程中的应用

研究了溶氧和ｐＨ值对赖氨酸产生菌ＦＢ４２发酵的影响，结合发酵过程的动力学分析，得出了分批发酵操作的溶氧和ｐＨ控制模式。结果表明两种控制都使发酵水平得到提高，但以溶氧控制更有效，在溶氧控制模式下，发酵的转化率从３３．６％提高到３８．１％。     

鸟嘌呤核苷补料发酵条件研究

采用新菌株Bacillus subtilis JSIM-518，在22L自控发酵罐上进行不同补料方式和所补原料的发酵研究，酵母粉连续补料，对鸟苷积累不甚明显，应用指数函数补料方式，匀速补入RNA和腺嘌呤物质，添加速率K值显得非常关键，当K=0．16时积累鸟苷最高，积累质量浓度为34．14g／L，高于和低于此值时，鸟苷的积累量都呈递减的趋势。     

代谢调节理论指导下的核黄素发酵条件

发表了从葡萄糖到核黄素的整条生物合成途径。根据这条代谢途径和Ｔ３０突变株的发酵条件试验结果，对阿舒假囊酵母合成核黄素的过程中碳基质流量在ＥＭＰ和ＨＭＰ途径中的分配，油和骨胶在核黄素合成中的不同作用，以及丙酮酸的氧化能力等与核黄素过量合成的关系进行了初步的讨论。     

恒pH补料分批培养技术培养谷胱甘肽合成酶系

采用一种新的补料分批培养技术 ,培养重组大肠杆菌生产谷胱甘肽合成酶系 .在分批培养和补料分批培养期间 ,采用不同的pH控制模式 :在发酵前期采用分批培养 ,加入碱以补偿pH值的降低 ;而在发酵后期 ,采用一种新的恒 pH补料分批培养方式 ,加入葡萄糖和碱调节发酵液的 pH .在这种模式中 ,根据培养过程中的pH变化确定pH参数 .实验结果表明 :同时设置发酵液的 pH上限和下限可避免恒 pH补料分批培养过程中葡萄糖的周期性缺乏问题 ;对于缓冲能力不同的发酵液 ,应设置不同的pH参数来进行 pH的控制     

里氏木霉 Rut C-30 液态发酵法生产纤维素酶

探讨了增强里氏木霉ＲｕｔＣ－３０产纤维素酶的方法，添加葡糖糖于培养基中，可促进菌体生长，但不能提高产酶；采用Ａｖｉｃｅｌ与麸皮复合碳源，以及使用ＫＨ２ＰＯ４－Ｋ２ＨＰＯ４缓冲系统控制发酵液ｐＨ，在摇瓶发酵条件下，可获得很高活力的纤维素酶，培养６ｄ，酶活可达到ＣＭＣａｓｅ１６６７～２０８４ｎｍｏｌ·ｓ－１·ｍｌ－１，ＦＰＡ１５０～２００ｎｍｏｌ·ｓ－１·ｍｌ－１．采用２．５Ｌ发酵罐培养，通过控制ｐＨ和溶氧，纤维素酶活力为ＣＭＣａｓｅ２２２３．８ｎｍｏｌ·ｓ－１·ｍｌ－１，ＦＰＡ１９４．５ｎｍｏｌ·ｓ－１·ｍｌ－１．     

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.     

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.