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1.
利用分子力学 (MM 2 )方法计算了 (1→ 3) β D 葡聚糖二糖结构单元全局最低能量构象 ,在此基础上搭建相对分子质量分别为 2 .0 5× 10 4 和 1.0 2 6× 10 5的 (1→ 3) β D 葡聚糖片段并进行分子几何全优化 .结果表明 ,(1→ 3) β D 葡聚糖的能量最低构象为单螺旋结构并且亲水性基团 (多羟基 )位于螺旋体的表面 ,从而认为这种构象可能是其具有刺激免疫和抗肿瘤活性的分子基础 .  相似文献   

2.
用水提取百合块茎粗多糖 ,经Sevag脱蛋白质 ,透析后经DEAE cellulose及SephadexG 10 0柱色谱纯化 ,得到百合纯多糖组分LBPS I .经完全酸水解 ,PC ,GC ,IR ,高碘酸氧化 ,Smith降解 ,甲基化分析 ,1H及13C NMR等研究百合多糖的化学结构 ,表明LBPS I的相对分子质量为30 2 0 0 ,比旋光度 [α]2 0D =+192 .3(c 0 .75 ,H2 O) ,特性粘度 [η]=14.0 6× 10 3 mL/ g .LBPS I是由α D (1,4 ) Glcp和α D (1,3) Glcp以 2∶1的比例交替形成主链 ,并有α D (1,6) Glcp侧链的葡聚糖 .小鼠移植性实体瘤研究表明 ,LBPS I对移植性黑色素B16和Lewis肺癌有较强的抑制作用  相似文献   

3.
目的 观察普伐他汀 (pravastatin)对异种胰岛移植物存活的影响。方法 将猪→小鼠胰岛移植模型分成A组 (对照组 )、B组 (CsA组 )、C组 (普伐他汀组 )、D组 (CsA +普伐他汀组 )。观察指标 :移植物存活时间、病理检查、免疫组化染色、血清NO含量及移植物IFN γmRNA的表达。结果 A、B、C和D组移植物平均存活时间分别为 (6 .2±0 .82 )d、(9.2± 1 .92 )d、(7.2± 1 .30 )d及 (1 1 .2± 1 .76)d,D组存活时间明显长于其它 3组 (P<0 .0 5) ;D组移植物浸润细胞较其它 3组少。术后第 4天 ,血清NO水平A组为 (1 0 5 .8± 1 9.3)mmol/L ,明显高于B组的 (88.2± 2 1 .4)mmol/L(P<0 .0 5)、C组的 (70 .7± 1 7.8)mmol/L(P<0 .0 1 )及D组的 (56 .3± 1 6 .4)mmol/L(P<0 .0 1 ) ,出现移植排斥时 ,C、D组的血清NO水平分别为 (83 .7± 1 0 .6)mmol/L及 (71 .3± 1 3 .8)mmol/L ,仍较A组低 (P<0 .0 5) ,B组为 (1 0 4 .7± 1 6 .3)mmol/L ,与A组比较差异无显著性意义 (P>0 .0 5)。术后第 4天血清IFN γmRNA表达 ,D组为 2 3 .5± 4 .6 ,较A组的2 8.8± 4 .8低 (P<0 .0 5) ,而B、C组与A组间差异无显著性意义 (P>0 .0 5)。结论 普伐他汀能抑制巨噬细胞活性 ,延长异种胰岛移植物存活 ,尤其与CsA联用效果更好  相似文献   

4.
小檗碱对大鼠阴茎海绵体磷酸二酯酶5mRNA水平的影响   总被引:3,自引:0,他引:3  
目的 :检测大鼠阴茎海绵体中磷酸二酯酶 5 (PDE5 )mRNA的表达 ,进而探讨小檗碱 (berberine ,Ber)的分子作用机制。 方法 :通过逆转录酶链反应 (RT PCR)技术检测大鼠阴茎海绵体中PDE5mRNA的表达。 结果 :大鼠阴茎海绵体中有PDE5A1和PDE5A2mRNA的表达 ,以PDE5A2为主要的异构酶。与内参照 β 肌动蛋白相比 ,对照组、Ber孵育 1和 3h组的PDE5A1及PDE5A2基因mRNA的相对表达量分别为 :0 .2 2± 0 .0 2 ,0 .4 1± 0 .0 1 ;0 .1 5± 0 .0 1 ,0 .34± 0 .0 2 ;0 .1 0± 0 .0 1 ,0 .1 2± 0 .0 1。与对照组相比 ,PDE5A1、PDE5A2的mRNA表达 ,在Ber孵育 1h组降低了 32 %和 1 7%,3h组降低了 5 5 %和 71 %,其中尤以应用Ber 3h后PDE5A2的mRNA减少最为明显 (n =5 ,P <0 .0 1 )。 结论 :Ber对NO cGMP信号通路的下游关键酶 (PDE5 )具有一定的调控作用 ,尤其是抑制PDE5A2的mRNA表达 ,为Ber治疗勃起功能障碍的分子机制之一。  相似文献   

5.
目的 :连续观察男性性腺功能低减病人尿卵泡刺激素 β亚单位 (β FSH)的排泄 ,探讨其对男性性腺功能低减的临床分类诊断和病理生理机制研究的意义。 方法 :4例健康成年男性 (年龄分别为 19、2 2、2 7、33岁 )、4例低促性腺激素型性腺功能低减男性病人 (年龄分别为 17、17、19、2 4岁 )和 5例高促性腺激素型性腺功能低减男性病人 (年龄分别为 16、16、17、2 0、2 2岁 ) ,连续留晨尿 30~ 32d ,其中 1例正常男性留取标本 6 3d。酶免法测定尿 β FSH ,以肌酐 (Cr)含量进行校正。 结果 :4例正常成年男性尿 β FSH总平均为 (1.16± 0 .2 0 ) μg/mgCr,均可出现波峰 ,最大峰值为 2 .76 μg/mgCr。 4例低促性腺激素型性腺功能低减男性病人 [Kallmann或特发性低促性腺激素型性腺功能低减 (IHH) ]尿 β FSH分别为 (0 .5 8± 0 .31)、(0 .93± 0 .4 7)、(0 .4 7± 0 .33)、(0 .6 0± 0 .4 0 ) μg/mgCr,曲线上未见明显波动。 5例高促性腺激素型性腺功能低减男性病人 (Klinefelter)尿 β FSH分别为 (3.0 2± 0 .93)、(4.36± 1.12 )、(4.79± 0 .78)、(4.6 4± 1.4 2 )、(3.88± 1.4 2 ) μg/mgCr,曲线上出现显著不规则波动 ,最大峰值达6 .83μg/mgCr。所有病人第二性征发育差 ,血清T水平显著低下。低促性腺激素?  相似文献   

6.
胰高血糖素样肽-2对短肠大鼠残留小肠代偿的影响   总被引:2,自引:0,他引:2  
目的 研究胰高血糖素样肽 2 (GLP 2 )对短肠大鼠残留小肠代偿的影响及机制。方法  75 %小肠切除大鼠随机分成空白 (SB)组、生长激素 (GH )组和GLP 2组。术后 6d行残留回肠黏膜形态学检测、细胞增殖核心抗原 (PCNA)测定及原位末端标记 (INST法 )染色。结果 GLP 2组回肠黏膜形态学指标显著高于SB组 (P <0 .0 5 ) ,并且其黏膜厚度显著高于GH组 (P <0 .0 5 )。GLP 2组PCNA指数显著高于SB组 (0 .5 1± 0 .0 9与 0 .40± 0 .0 6比较 ,P <0 .0 5 ) ,但和GH组比较差异无统计学意义 (P >0 .0 5 )。GLP 2组细胞凋亡显著低于SB组 (67.7± 10 .1与 81.7± 12 .9比较 ,P <0 .0 5 ) ,但和GH组比较差异无统计学意义 (P >0 .0 5 )。结论 GLP 2能刺激小肠黏膜上皮增生 ,抑制凋亡 ,显著促进短肠大鼠残留小肠黏膜的形态代偿。  相似文献   

7.
上皮钙粘合素和连环素在胃癌中的表达及其意义   总被引:2,自引:0,他引:2  
近年国内外学者发现上皮钙粘合素 (E cadherin ,E cd)、α 连环素 (α catenin ,α C)和 β 连环素 (β catenin ,β C)在多种肿瘤中表达下降或缺失[1 3] 。我们应用免疫组化法研究胃癌、胃不典型增生和远癌组织中E cd、α C和 β C表达及其临床意义。材料与方法1.标本 :收集我院 1990年 6月至 1993年 6月胃癌根治手术标本 48例 ,男 32例 ,女 16例 ,年龄 2 0~ 6 9岁 ,平均 5 1 2岁 ;其中低分化癌 2 8例、中高分化癌 2 0例 ;PTNM分期Ⅰ期13例 ,Ⅱ期 13例 ,Ⅲ期 2 2例。另取 15例远癌 (距癌 >3cm)胃…  相似文献   

8.
结合工业发酵的特点 ,研究了营养因子对鸡腿蘑 (毛头鬼伞 )胞外多糖产量的影响 ,筛选到适合其胞外多糖分泌的优化培养基配方 :葡萄糖 2 .0 % ,玉米粉 (6 0目 ) 1.0 % ,麸皮粉 (6 0目 )0 .3% ,VB110mg/L ,KH2 PO4 0 .1% ,MgSO4 ·7H2 O 0 .1% ,在此基础上进行摇瓶发酵曲线的测定 ,确定生产胞外多糖的适宜发酵周期为 4d ,发酵液中产量最高可达 96 .3mg/dL .  相似文献   

9.
下肢静脉曲张血管重塑的研究   总被引:3,自引:2,他引:1  
程勇  时德 《中华实验外科杂志》2002,19(2):134-136,T004
目的 探讨下肢静脉曲张血管重塑的实质、特征以及在下肢静脉曲张发生机制中的意义。方法 采用Masson染色、免疫组织化学、电镜观察以及图像分析方法研究 1 8例曲张静脉和1 4例正常静脉壁中平滑肌细胞、胶原纤维、Ⅰ型胶原、Ⅲ型胶原和α actin的结构变化。结果 曲张静脉内膜改变以内膜增生为主 ,中膜以中膜增厚为主 ,平滑肌细胞从收缩表型向合成表型转化。α actin在内膜 (3 .67± 0 .69) %和中膜 (1 2 .0 9± 2 .1 4 ) %的体密度比正常静脉 [(8.91± 0 .94) %和(2 1 .42±1 .49) % ]均显著减少 (P <0 .0 1 ) ;Ⅲ型胶原在内膜 (1 4 .1 0± 0 .93) %和中膜 (1 9.58±1 .51 ) %的体密度比正常静脉 [(8.41± 0 .86) %和 (1 2 .97± 1 .1 5) % ]均显著增多 (P <0 .0 1 ) ;I型胶原中膜的体密度 (2 3 .52± 1 .67) %比正常静脉 (1 6 .2 8± 1 .44) %也显著增多 (P <0 .0 1 )。结论下肢静脉曲张血管重塑的平滑肌细胞异常增生 ,从收缩表型向合成表型转化 ,以及细胞外基质中胶原异常改变 ,都使得管壁收缩效应降低 ,静脉因而易曲张  相似文献   

10.
为了保持茶多糖的活性 ,采用低温水提、酶提二次结合法提取茶多糖 .第一次在 5 0℃、茶叶与水的质量比为 1∶1 5、水提取 3 0min ,多糖的提取率为 2 .3 3 % ,粗多糖 (干重 )的提取率为6.82 % ;过滤后 ,滤渣用 pH 4.6的柠檬酸 柠檬酸钠缓冲液加纤维素酶提取 ,经正交试验确定酶提最佳工艺参数为 5 5℃、茶叶与水的质量比为 1∶1 4、酶用量 2 .2 μL/g(以茶叶质量计 ) ,反应时间为1 2 0min ,其多糖的提取率为 0 .64% ,粗多糖 (干重 )的提取率为 1 .1 1 % ,分别占二次总提取量的2 1 .5 %和 1 4.0 % ,而在相同条件下无酶提取 ,提取率仅为 0 .3 9%和 0 .5 6% .相对水提法 ,酶法的多糖提取率分别增加 63 .3 %和 98.9% ,多糖总提取率达 2 .97% ,粗多糖 (干重 )的总提取率为7.93 % .采用酶法提取的茶多糖具有较强抑制α 淀粉酶活力的能力 .  相似文献   

11.
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 (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.  相似文献   

12.
Don Dame 《Artificial organs》1996,20(5):613-617
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.  相似文献   

13.
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.  相似文献   

14.
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.  相似文献   

15.
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.  相似文献   

16.
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.  相似文献   

17.
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.  相似文献   

18.
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.  相似文献   

19.
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.  相似文献   

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