大叶紫薇叶中降血糖活性成分的筛选

为筛选大叶紫薇叶中具有降血糖活性的成分,采用3T3-L1细胞葡萄糖消耗模型作为检测手段,对大叶紫薇叶提取物采用HP-20树脂吸附、溶剂萃取、制备薄层分离和制备高效液相分离,导向筛选具有降血糖作用的各分离组分.结果发现,大叶紫薇叶中corosolic acid、熊果酸和总三萜具有降血糖活性.     

茶叶儿茶素单体的分离纯化及鉴定

将茶提取物（茶多酚）先经SephadexLH-20柱层析分离，脱除咖啡因和色素，并将其中7种儿茶素分成2个流分.再用半制备型HPLC分离纯化，得到7种儿茶素的单体化合物.用UV、IR、NMR及MS等方法鉴定和验证了其化学结构，7种单体儿茶素化合物的纯度均大于99%，总得率为66.7%，总回收率为82.1%.     

田菁的开发与利用——田肉粉的化学成分(Ⅱ)

研究了田菁种子炼胶后的副产物田肉粉的化学成分。从田肉粉中用层析等手段分得两个化合物,经元素分析与光谱分析(UV,IR,1~H-NMR,MS)确定其一为2-羟基-3-甲基-γ-吡喃酮,是一新的吡喃酮类化合物,其二为6-氨基-9-β-D-呋喃核糖嘌呤,是一已知的嘌呤衍生物,为首次从田菁属植物中分离得到。     

大豆皂甙A的分离与ESI/MS分析

大豆胚芽中皂甙的含量是子叶的6～14倍,soyasaponin A仅存在于胚芽中.以硅胶柱色谱和制备高效液相色谱法从大豆胚芽的乙醇提取物中分离出二种A组皂甙,进行定性反应.UV和ESI/MS分析确证其结构为soyasaponin A     

油茶叶中油脂抗氧成分研究

首次从油茶叶中分离得到了三种黄酮体化合物,经UV,IR,~1HNMR,~(13)CNMR,EI-MS及FAB-MS等仪器分析,鉴定为槲皮素(1),槲皮素-3-0-鼠李吡喃糖甙(2)和槲皮素-3-0-葡萄吡喃糖-(6→1)鼠李吡喃糖甙(3)。在Metrohm Rancimat中测定了它们的诱导时间,显示这些化合物对于猪油及菜籽色拉油都是良好的抗氧剂,尤其是槲皮素对于猪油的抗氧性在相同添加量时比BHT高得多。此外还对这类化合物的抗氧活性与其结构的关系作了初步探讨。     

超滤分离癞葡萄水溶性降糖活性物质

采用超滤法从癞葡萄水提物中初步分离降血糖活性物质.考察了进料流量、操作压力、操作温度及料液质量浓度等工艺参数对超滤过程中膜通量的影响,并对超滤后两组分的相对分子质量分布及降血糖活性进行了测定.结果表明:用截留相对分子质量为10 000的中空纤维膜对癞葡萄水提物进行超滤分离的最适工艺条件为:进料流量200 L/h、温度25 ℃、压力0.10 MPa、料液质量浓度20 g/L.超滤有效地将癞葡萄水提物分成两个组分,其中相对质量较小的组分具有显著的降血糖活性,而相对质量较大的组分不具有降血糖活性.     

癞葡萄皂苷的分离、纯化及其结构鉴定

分别使用AB-8大孔树脂、C18填料柱,从癞葡萄醇提取物中分离纯化癞葡萄皂苷,并用高效液相色谱法测定所得化合物的相对含量,最后使用质谱、核磁共振的方法对其分子结构进行了鉴定.结果成功分离纯化出一种皂苷,经测定,该皂苷的纯度为95.70%,结构鉴定为葫芦烷-5-烯-3β,22,23,24,25-四羟基-3-O-3-β-D-吡喃葡萄糖(1→6)-D-吡喃葡萄糖苷.     

雪里蕻腌菜特征风味物质的分离和鉴定

运用色-质(GC/MS)联用技术对雪里蕻腌菜的风味物质进行了研究，以期发现能显著影响其风味特性的关键性成分.首先，对雪里蕻腌菜卤汁的乙醚萃取浓缩液组分进行了鉴定，结果发现有机酸组分8个，醇类组分4个，腈类组分2个，酯类组分1个，芳香烃2个.经动态顶空吸附雪里蕻腌菜挥发性组分并进行组分离，在GC-MS图谱上进行组分的分离鉴定，其特征风味在碱性组分中嗅感强烈.雪里蕻腌菜挥发性成分经GC-MS检测解析为烃类、醇类、酯类、腈及杂环化合物，其中丁烯腈及苯并噻唑与雪里蕻腌菜特征风味形成密切相关.     

HPLC测定牛奶和虾仁中氯霉素残留

建立了一种检测虾仁和牛奶中氯霉素残留的高效液相色谱(紫外检测,即LC/UV)方法和液相色谱-电喷雾电离质谱联用(LC/ESI MS)检测方法.色谱分离选用SymmetryC18柱,以乙腈-水为流动相.紫外检测波长为278nm,质谱采用选择性离子检测(M/Z321.0,[M H]-).样品制备省去传统的多次液 液萃取过程,采用有机溶剂直接提取,转溶后,用固相萃取方法净化样品.虾仁和牛奶样品的平均回收率分别为93.7%和96.0%;检测限:LC/UV为2.5μg/kg和8.3μg/kg;LC/ESI MS为1.3μg/kg和4.5μg/kg.方法准确灵敏,样品预处理较简便快速.     

酸桔果皮油的特征香气成分

为评价酸桔果皮的特征香气成分,先用同时蒸馏与萃取法(SDE)提取酸桔果皮的精油,并用硅胶柱将精油分成碳氢化合物和含氧化合物两大部分.含氧化合物部分具有果皮油的特征香气,用GC/MS对该部分进行了分析,鉴定出56种含氧化合物成分,然后用GC-Sniffing方法评价了酸桔果皮油的特征香气成分,明确了顺式氧化沉香醇、沉香醇、顺式氧化柠烯、香茅醛、香茅醇、香芹酮以及一些脂肪族醛等12种成分对酸桔果皮的香气影响.用这些成分按适当比调配成的混合液基本上能够代表原果皮的香气.     

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.     

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.     

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.