Ang-1在去卵巢骨质疏松症大鼠骨组织中表达变化以及中医不同治法对其影响的实验研究

目的观察去卵巢骨质疏松症模型大鼠的骨组织中血管生成素1(Ang-1)mRNA和蛋白含量变化,及中药不同方剂对其影响,探讨中药组方治疗骨质疏松的可行性。方法骨质疏松症模型的建立采用切除雌性大鼠双侧卵巢的方法。运用补肾填精中药复方、活血化瘀中药复方、补肾活血中药复方对模型大鼠灌胃12周,用骨疏康作为阳性药物对照组,还有正常组和模型空白组。RT-PCR检测各组骨组织Ang-1mRNA相对表达量;ELISA法检测各组骨组织Ang-1蛋白含量。结果去卵巢骨质疏松症模型大鼠的骨组织中Ang-1mRNA相对表达量与正常组比较,显著降低(P0.01);与模型空白组比较,各个用药组Ang-1mRNA相对表达量显著升高(P0.01);但各个用药组间比较无统计学意义。去卵巢骨质疏松症模型大鼠骨组织中Ang-1蛋白含量与正常组比较,显著降低(P0.01);与模型空白组比较,各个用药组Ang-1含量显著升高(P0.01);各个用药组间比较,补肾活血组Ang-1含量升高最为显著,与补肾填精组和活血化瘀组比较有显著性差异(P0.01)。结论补肾活血中药复方可提高Ang-1mRNA相对表达量及其蛋白含量,且优于单纯的补肾填精和活血化瘀中药复方,起到防止骨质疏松症的作用。     

中医不同治法对绝经后骨质疏松症大鼠骨组织Hedgehog信号通路mRNA和蛋白表达的影响

目的观察去卵巢骨质疏松症大鼠模型骨组织Hedgehog信号通路中SHH、GLI1 mRNA和蛋白活性变化,探究中药防治骨质疏松症病机的分子生物学机制。方法实验采用切除雌性SD大鼠双侧卵巢的方式建立骨质疏松症模型,运用补肾填精中药复方、活血化瘀中药复方、补肾活血中药复方对模型大鼠进行干预12周,用骨疏康作为阳性药物对照组,以及正常组和模型组。ELISA法检测各组骨组织SHH、GLI1蛋白含量;RT-PCR检测各组SHH、GLI1 mRNA相对表达量。结果骨组织SHH、GLI1蛋白与正常组相比模型组含量明显减少(P0.01),与模型组相比较,各用药组均明显增加(P0.01)。结论骨质疏松症的发生机制与Hedgehog信号传导通路SHH、GLI1 mRNA和蛋白活性下降有关;补肾填精中药复方、活血化瘀中药复方、补肾活血中药复方通过激活Hedgehog信号传导通路中的SHH、GLI1,以促进骨形成,抑制骨吸收,起到防止骨质疏松症的作用。     

Hedgehog信号通路与“肾虚血瘀”骨代谢失常的实验研究

目的观察去卵巢骨质疏松症模型大鼠的骨组织和肾组织中Hedgehog信号通路细胞表面受体Patched-1(PTCH1)和Gli3mRNA和蛋白含量变化及补肾填精、活血化瘀中药复方对其影响,探讨中药组方治疗绝经后骨质疏松症的可行性以及绝经后骨质疏松症的发病机制与Hedgehog信号通路的关系。方法采用切除雌性大鼠双侧卵巢的方法建立绝经后骨质疏松症模型,分别给予补肾填精中药复方、活血化瘀中药复方、骨疏康对模型大鼠灌胃12周。然后将大鼠分为补肾填精组、活血化瘀组、阳性对照组、正常组和模型空白组,其中骨疏康作为阳性药物为阳性对照组。运用RT-PCR检测各组大鼠骨组织和肾组织PTCH1和Gli3mRNA相对表达量;通过ELISA法检测各组大鼠骨组织和肾组织PTCH1和Gli3蛋白含量。结果各组大鼠股骨和肾组织中PTCH1mRNA及蛋白表达方面:与正常组比较,模型组显著升高(P0.01);与模型组比较,补肾填精组、活血化瘀组、阳性对照组显著降低(P0.01);各个用药组间比较,补肾填精组下调优于活血化瘀组,具有显著性差异(P0.01)。各组大鼠股骨和肾组织中Gli3mRNA及蛋白表达方面:与正常组比较,模型组显著升高(P0.01);与模型组比较,补肾填精组、活血化瘀组、阳性对照组显著下降(P0.01);各个用药组间比较,补肾填精组下调优于活血化瘀组,具有显著性差异(P0.01)。结论 PTCH1mRNA及蛋白含量和Gli3mRNA及蛋白含量在去卵巢骨质疏松症模型大鼠骨组织和肾组织中显著升高,提示PTCH1和Gli3可能参与绝经后骨质疏松症骨代谢失衡的发生和进展。补肾填精中药复方和活血化瘀中药复方可下调PTCH1和Gli3mRNA相对表达量及其蛋白含量,这可能是起到防治绝经后骨质疏松症的作用机制之一,并且补肾填精法优于活血化瘀法。     

基于Wnt信号通路探讨补肾益气活血中药复方对去卵巢大鼠骨质疏松症的作用机制

目的观察去卵巢大鼠骨质疏松症模型骨、肾组织中Wnt3a信号蛋白的变化,探究补肾益气活血中药复方对骨质疏松症作用的分子生物学机制。方法将雌性大鼠75只随机分为5组:正常组、模型组、福善美组、补肾益气活血方低剂量组、补肾益气活血方高剂量组,后4组摘除大鼠双侧卵巢法复制骨质疏松症模型,连续给药12周后以双能X线检测骨密度,ELISA法检测血清碱性磷酸酶(alkaline phosphatase,ALP)、抗酒石酸酸性磷酸酶(tartrate resistant acid phosphatase,TRAP)以及骨、肾组织中Wnt3a蛋白表达。结果与正常组比较,模型组骨密度明显降低,血清ALP明显减少,血清TRAP明显升高,骨及肾组织中Wnt3a蛋白表达明显减少;与模型组相比较,各治疗组骨密度、血清ALP及骨、肾组织Wnt3a蛋白均有不同程度的升高。结论骨质疏松症的发生机制与Wnt3a蛋白变化有关;补肾益气活血中药复方的疗效作用机制是通过调节和改善Wnt3a蛋白的表达,激活Wnt3a/β-catenin信号传导通路,促成骨分化,抑制破骨细胞,起到防治骨质疏松症的作用。     

骨质疏松症大鼠肾组织中Smmf1 mRNA和蛋白表达的实验研究

目的通过研究摘除卵巢致骨质疏松症大鼠肾组织中Smurf1的mRNA和蛋白的表达,揭示摘除卵巢致骨质疏松症的病理机制,并研究补肾中药防治疗效及其作用机制。方法摘除雌性大鼠双侧卵巢的方法复制骨质疏松症模型,采用具有补肾壮骨益精作用的纳米钙补肾中药（高、低剂量）对实验大鼠治疗12w,以骨疏康颗粒剂、盖天力片作为阳性对照组,正常大鼠、假手术组作为标准对照组,模型大鼠作为空白对照组,并与补脾方剂（补中益气汤）作疗效的比较。用RT-PCR法、Western印迹法检测骨质疏松症大鼠肾组织中Smurf1的mRNA和蛋白表达。结果RT-PCR及Western方法检测,正常大鼠肾组织中存在Smurf1的mRNA和蛋白表达;与正常组、假手术组比较,模型组Smurf1 mRNA和蛋白的表达水平在肾组织中明显降低。用药12w后,与模型组比较,补肾高、低剂量组、补脾组、盖天力组、骨疏康组均可明显上调Smurf1 mRNA和蛋白在肾组织中的表达水平。其中补肾高剂量组上调幅度大于其他各用药组。结论①正常大鼠肾组织中Smurf1可以在基因、蛋白水平表达;②骨质疏松症的发生,可能与肾组织中Smurf1的mRNA和蛋白表达的变化有关;③纳米钙补肾中药通过调控肾组织中Smurf1的mRNA和蛋白表达,对于骨质疏松症有一定的防治作用。     

补肾益髓中药复方对去卵巢骨质疏松症大鼠骨组织Runx2 mRNA及蛋白表达的影响

目的观察去卵巢骨质疏松症大鼠骨组织Runx2 mRNA及蛋白表达,探讨绝经后骨质疏松症(Postmenopausal Osteoporosis,PMOP)的发病机制以及补肾益髓中药复方的疗效机理。方法去卵巢复制骨质疏松症大鼠模型,实验设正常组、模型组、假手术组、补肾益髓中药复方组、钙尔奇D组、骨疏康组。术后7d开始灌胃给药12周。应用XR-36型双能X线骨密度仪测定股骨骨密度,应用OLYMPUS BX51显微镜观察股骨头石蜡切片HE染色显微形态结构,实时定量RT-PCR及Western Blot检测骨组织Runx2 mRNA及蛋白表达。结果 (1)与正常组、假手术组比较,模型组股骨骨密度明显降低(P0.001、P0.05),骨组织Runx2 mRNA及蛋白表达明显降低(P0.001)。(2)与模型组比较,补肾益髓中药复方组、骨疏康组股骨骨密度明显升高(P0.05),补肾益髓中药复方组(P0.001)、钙尔奇D组(P0.05)、骨疏康组(P0.01)骨组织Runx2 mRNA及蛋白表达明显上调。(3)与钙尔奇D组、骨疏康组比较,补肾益髓中药复方组骨组织Runx2 mRNA(P0.01、P0.05)及蛋白(P0.001)表达均明显升高。(4)股骨头石蜡切片HE染色显微形态结构:与正常组、假手术组比较,模型组骨小梁形态结构完整性差,有些部位破坏、断裂,余留骨重建空间较多;各给药组骨小梁形态结构均改善,结构较紧密,余留骨重建空间减少,其中以补肾益髓中药复方组改善最明显。结论骨组织Runx2 mRNA及蛋白表达降低可能是PMOP的发病机制之一;补肾益髓中药复方可能通过上调骨组织Runx2 mRNA及蛋白表达有效防治PMOP,其作用优于钙尔奇D、骨疏康。     

补肾复方对去卵巢大鼠MEK1、ERK2基因表达的调控 作用

目的研究补肾中药复方(鹿茸、牡蛎、淫羊藿)对去卵巢骨质疏松症大鼠的影响,探讨肾虚骨质疏松症的病理机制,为中医药防治骨质疏松症提供实验依据。方法采用摘除雌性大鼠双侧卵巢的方法复制骨质疏松症模型,以正常组作为标准对照,模型组作为空白对照,盖天力组作为阳性对照,补肾中药复方低、中、高剂量组作为实验组。各用药组灌胃给药12周。采用腹主动脉取血法采集大鼠血清测定血骨钙素(BGP)和抗酒石酸酸性磷酸酶(TRACP),并用DEXA骨密度仪检测左侧股骨骨密度;右侧股骨匀浆提取骨组织中的Total RNA,RT-Real Time PCR,检测MEK1及ERK2的mRNA表达水平。结果模型组BGP水平显著低于正常组(P0.01),TRAP水平较正常组显著升高(P0.01);正常组和补肾中药复方组的股骨骨密度均高于模型组(P0.05);ERK2 mRNA相对表达量明显高于模型组(P0.01),MEK1mRNA相对表达量明显低于模型组(P0.01)。结论补肾中药复方具有防治去卵巢大鼠骨质疏松的作用,其机制与调控MEK1、ERK2基因表达有关。     

补肾中药对骨质疏松症大鼠下丘脑BMP-4、Smad6 mRNA及蛋白表达的影响

目的探索肾虚骨质疏松症的病理机制,研究补肾中药对肾虚骨质疏松大鼠防治作用的机理。方法实验采用去双侧卵巢的方法,建立肾虚骨质疏松症模型。补肾中药复方（高、中、低）剂量对实验大鼠治疗12周,以骨疏康颗粒、盖天力牡蛎钙作为阳性对照药,并设正常对照组和模型空白组。用RT-PCR法、Western印迹法检测肾虚骨质疏松症大鼠下丘脑组织中BMP-4、Smad6 mRNA和蛋白表达。结果①与正常组比较,模型空白组大鼠下丘脑组织中的BMP-4 mRNA和蛋白表达水平明显增强;Smad6 mRNA和蛋白表达水平明显降低。②与模型空白组比较,补肾中药组对模型大鼠下丘脑组织中的BMP-4 mRNA和蛋白表达明显降低;而Smad6 mRNA和蛋白表达明显增强。结论肾虚骨质疏松症的病理机制为肾精不足,骨髓、脑髓失养,表现在下丘脑-垂体-靶腺轴的调控失常,包括下丘脑组织的细胞因子及其信号传导通路的异常。     

补肾方药对骨质疏松防治的实验研究

目的 探讨补肾方药对骨质疏松的防治作用及其机理。方法 本研究选用3种模型，即地塞米松和卵巢切除所诱发的骨质疏松模型，自然衰老的大鼠骨质疏松模型，并给予中药治疗。测定大鼠骨密度、骨代谢相关生化指标及骨形态计量学指标及基因表达分析。结果 补肾方药可显提高地塞米松所致骨质疏松大鼠的骨密度、血清骨钙素水平，降低尿钙排泄，同时，促进骨组织中I型胶原和LMP－1 mRNA表达，补肾方药还提高小肠黏膜CaBp-D9K基因表达，从而使小肠黏膜钙结合蛋白（CaBp)的合成增加，促进小肠对钙的吸收；补肾方药可提高卵巢切除所诱发的骨质疏松大鼠的骨密度，促进骨组织中I型胶原mRNA及小肠黏膜中VDR mRNA的表达，提高卵巢切除大鼠血清雌激素的水平，同时，提高骨组织中雌激素受体α和β（ERα，ERβ）的表达，增加雌激素对骨代谢的调节作用；补肾方药改善老年骨质疏松大鼠骨代谢，降低尿钙排泄，通过提高骨转换，主要是促进骨形成防止骨量丢失。结论 补肾方药通过多环节、多途径，调节骨质疏松大鼠的骨形成与骨吸收，使其达到骨形成与骨吸收相偶联，而防治骨质疏松。     

中医不同治法对绝经后骨质疏松症大鼠骨骼、骨骼肌甲状旁腺激素相关蛋白（PTHrP)含量影响的比较研究

目的观察补肾、健脾、活血法对骨质疏松症大鼠骨骼、骨骼肌甲状旁腺激素相关蛋白(PTHrP)含量变化的影响。方法将SD雌性大鼠分为正常组、模型组、补肾组、健脾组、活血组。采用酶联免疫法测定小鼠骨骼、骨骼肌PTHrP含量变化。结果(1)与正常组比较,模型组大鼠骨骼的PTHrP含量显著降低(P0.01);与模型组比较,补肾组、健脾组、活血组骨骼的PTHrP含量明显升高(P0.01),其中补肾组升高程度比较明显。(2)与正常组比较,模型组大鼠骨骼肌的PTHrP含量显著降低(P0.01);与模型组比较,补肾组、健脾组、活血组骨骼肌的PTHrP含量明显升高(P0.01),其中健脾组升高程度比较明显。结论 (1)骨质疏松症的形成,可能与骨骼、骨骼肌协调性下降有关。(2)补肾、健脾方法通过提高骨质疏松症大鼠的骨骼、骨骼肌PTHrP含量,对骨质疏松症具有一定的防治作用。     

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.