奥美拉唑对大鼠减体积肝移植后肝再生的影响

目的观察奥美拉唑对大鼠减体积肝移植肝细胞再生的影响。方法建立大鼠减体积肝移植模型，实验组移植后即时给予奥美拉唑，对照组予生理盐水。两组分别于肝移植术后分为5组（n=8），观察术后3、5、7、10、14d血清丙氨酸转氨酶、天冬氨酸转氨酶值、移植肝重／供肝减体积前全肝重比值、移植肝细胞有丝分裂指数（MI）、增殖细胞核抗原（PCNA）表达指数、溴脱氧尿嘧啶核苷（BrdU）掺入指数及血清胃泌素值。结果大鼠减体积肝移植术后5d肝细胞再生达高峰，实验组的再生活性显著高于对照组，MI为（2．54±0．24）％和（1．71±0．16）％（P〈0．01）、PC—NA指数为（26．96±2．09）％和（18．73±1．94）％（P〈0．01）、BrdU指数为（10．24±1．11）％和（5．75±0．88）％（P〈0．01）。术后7d，实验组和对照组移植肝重／全肝重比值分别为（76．3±1．6）％和（71．2±1．0）％（P〈0．05），血清胃泌素水平分别为（441．9±25．9）ng／L和（292．9±14．2）ng／L（P〈0．05）。术后14d，实验组和对照组移植肝重／全肝重比值分别为（94．5±1．7）％和（86．9±1．5）％（P〈0．01），血清胃泌素水平分别为（487．8±29．4）ng／L和（291．7±21．6）ng／L（P〈0．01）。实验组和对照组血清ALT、AST值差异无统计学意义。结论奥美拉唑能促进减体积肝移植术后的肝细胞再生，其作用可能与胃泌素分泌增高有关。     

低温氧合血微流量持续灌注保存大鼠心脏的效果

目的探讨低温氧合血微流量持续灌注保存大鼠心脏的效果。方法切取Wistar大鼠心脏，随机分为3组，实验组的心脏以4℃氧合血微流量（1ml／h）持续灌注低温保存10h；对照组的心脏以4℃St．Thomas液微流量持续灌注低温保存10h；单纯冷保存组的心脏以4℃St．Thomas液单纯浸泡保存10h。保存后的鼠心用Langendorff装置灌注，生物机能实验系统测定血流动力学指标；高效液相色谱仪测定心肌细胞的ATP含量；光镜和电镜观察心肌组织和线粒体的形态学改变。结果在再灌注30min时，实验组的左心室收缩压（LVSP）为（38．25±3．84）mm Hg，左心室发展压（LVDP）为（32．54±4．01）mm Hg，左心室压力微分（±dp／dt）为（1080±123）mm Hg／s；对照组的LVSP为（34．48±4．68）mm Hg，LVDP为（19．27±4．63）mmHg，±dp／dt为（935±196）mmHg／s；单纯冷保存组的LVSP为（32．14±4．95）mmHg，LVDP为（16．99±4．85）mmHg，±dp／dt为（825±302）mmHg／s，实验组的上述血流动力学指标优于对照组和单纯冷保存组（P〈0．05）。实验组心肌细胞的ATP含量为（1．759±0．502）μmol／L，对照组的ATP为（1．453±0．573）μmol／L，单纯保存组的ATP为（1．059±0．463）μmol／L，实验组的ATP含量明显高于对照组和单纯冷保存组（P〈0．05）。实验组的心肌组织和细胞超微结构的变化轻于对照组和单纯冷保存组。结论低温氧合血微流量持续灌注能改善大鼠心脏的保存效果。     

大鼠肝移植后早期血清一氧化氮的变化及其意义

目的探讨大鼠肝移植后早期血清一氧化氮（NO）的变化情况及其意义。方法将SD大鼠随机分成A、B、C三组，进行肝移植．供、受者均为SD大鼠。A组于移植肝恢复血流2h、B组于移植肝恢复血流4h、C组于移植肝恢复血流6h时采取受者的下腔静脉血和左肝叶组织．测定血清丙氨酸转氨酶（ALT）和NO含量．免疫组化法测定移植肝组织中核因子．κB p65亚单位（NF-κB p65）的表达，并观察肝组织病理学变化；每组均于移植肝恢复血流时收集5min的胆汁，测量5min胆汁分泌量。结果A组的5min胆汁分泌量为（3．73±1．11）μl．明显高于B组的（2．35±0．92）μ和C组的（2．23±0．81）μl（P〈0．05）。A组血清ALT含量为（468±36）IU／L．B组为（619±49）IU／L．C组为（820±65）IU／L，A组明显低于B、C组（P〈0．05），B组明显低于C组（P〈0．05）。A组血清NO含量为（14．2±1．5）μmol／L，明显高于B组的（10．5±1．2）μmol／L和C组的（10．3±1．1）μmol／L（P〈0．05）。A组肝组织中NF-κB p65表达阳性细胞百分率为（23．5±1．9）％．B组为（43．8±3．8）％，C组为（48．6±5．1）％．A组明显低于B、C组（P〈0．05）。病理学观察显示．随着移植肝脏再灌注时间的延长，肝组织损伤呈进行性加重。Pearson相关性分析提示．NO与血清ALT水平及NF-κB p65表达呈明显的负相关（r值分别为-0．74和-0．77，P〈0．01）。结论移植肝脏再灌注早期．血清NO下降，NF-κB的活性逐渐增强．移植肝脏的功能和组织损伤呈加重趋势。     

粘着斑激酶在PDGF-BB诱导MHCC-97H细胞黏附侵袭中的作用

目的观察不同浓度血小板衍生生长因子（PDGF-BB）诱导MHCC-97H细胞中粘着斑激酶（focal adhesion kinase，FAK）mRNA的动态变化及FAK在细胞黏附、侵袭的作用。方法不同浓度（1，2．5，5，10，25ng／m1）PDGF-BB诱导MHCC-97H人肝癌细胞，Real-time PCR方法检测FAK及MMP-2的mRNA动态变化，黏附实验、侵袭实验分别检测诱导后MHCC-97H细胞的黏附、侵袭能力的变化。结果诱导后MHCC-97H细胞FAKmRNA水平上调，在10ng／ml浓度时达到最高，为对照组的112．6倍；MMP-2mRNA水平上调并与FAKmRNA水平上调呈一致性，在10ng／ml浓度时达到最高，为对照组的56．9倍。诱导后各组黏附率分别为（66±1．84）%、（69±1．41）％、（69±2．42）％、（71±1．37）%和（66±3．28）%，与对照组的（54±2．08）％比较均有统计学意义（P〈0．001）；诱导后5ng／ml和10ng／ml组侵袭细胞数分别为（26．63±4．5）、（28．75±4．2）个，与对照组（21．5±4．0）个比较有显著性差异（P〈0．05，P〈0．001）。诱导后黏附率与侵袭细胞数变化在10ng／ml浓度时都达到高峰。结论PDGF-BB上调MHCC-97H细胞中FAK表达，上调FAK促进MHCC-97H细胞的黏附和侵袭能力。     

微管解聚剂在缺氧早期大鼠心肌细胞线粒体损害中的作用

目的了解微管解聚剂在缺氧早期大鼠心肌细胞线粒体损害中的作用。方法常规方法分离培养Wistar乳鼠心肌细胞，分为正常组、微管解聚组（培养液中加入4μmol／L秋水仙碱）、缺氧组、缺氧解聚组（4μmol／L秋水仙碱联合缺氧处理）。分别采用激光共聚焦显微镜检测4组细胞线粒体分布情况，透射电镜观察线粒体形态变化，生物氧耗呼吸仪检测呼吸调节比（RCR），高效液相色谱仪检测腺苷三磷酸（ATP）含量。缺氧组及缺氧解聚组所设时相点为缺氧后10、20、30、60min。结果正常组线粒体呈粒状、排列规则，微管解聚组较之发生轻微改变：缺氧20、30、60min，缺氧解聚组线粒体分布的无规律性及形态结构损害均较缺氧组严重；细胞RCR分别为1．58±0．37、1．51±0．32、1．12±0．11，明显低于缺氧组3．85±0．56、2．98±0．44、1．79±0．73（P〈0．01）；ATP含量分别为（419±83）、（326±73）、（295±58）ng／mg，亦明显低于缺氧组（475±68）、（397±59）、（336±67）ng／mg（P〈0．01）。结论微管解聚剂可加重缺氧引起的心肌细胞线粒体分布紊乱和形态结构损害，以及线粒体呼吸功能和能量代谢障碍，它在线粒体缺氧损害机制中具有重要作用。     

新型衍生肽对淋巴细胞免疫功能及大鼠异基因移植肾存活的影响

目的 探讨新型组织相容性白细胞抗原（HLA）衍生肽RDPI258对淋巴细胞免疫功能及大鼠移植肾脏存活时间的影响。方法 采用人工标准固相合成法合成HLA衍生肽RDP1258，^3H—TdR掺入法观察其在体外对人外周单核细胞增殖反应的影响。建立原位大鼠异基因肾移植模型32只，设RDP1258＋CsA治疗组、RDP1258治疗组、CsA治疗组及对照组4组，每组8只，观察大鼠移植肾脏存活时间及移植肾功能。结果RDP1258可显著抑制淋巴细胞转化及单向混合淋巴细胞增殖反应（MLR）；RDP1258＋CsA治疗组受体大鼠平均存活63．4d，对照组平均存活9．4d，CsA治疗组平均存活16．9d，RDP1258治疗组平均18．3d，各组与联合治疗组比较差异有统计学意义（P〈0．05）。对照组在术后5d切除对侧肾脏后血清肌酐浓度（450．0±84．2）μmol／L，CsA及RDP1258组血清肌酐浓度呈现缓慢上升趋势，分别为（360．0±78．4）及（350．0±65．8）μmol／L，与联合治疗组（47．4±11．2）μmol／L相比，差异有统计学意义（P〈0．05）。结论 RDP258能显著抑制人外周单核细胞丝裂原或同种抗原刺激引起的增殖反应，围手术期应用HLAⅠ类分子衍生肽结合小剂量CsA，能显著延长异基因移植物存活时间及功能，RDP1258可能成为一种新型的器官移植免疫调节药物。     

落新妇甙对心脏移植效应性T细胞磷脂酰肌醇信号通路的影响

目的探讨落新妇甙对心脏移植效应性T细胞磷脂酰肌醇-3-激酶／蛋白激酶B（PI-3K／PKB）信号传导通路的影响。方法分离BALB／C小鼠心肌细胞（2×10s／m1）和C57BL／6小鼠的脾细胞（1×10^6／ml），前者作刺激细胞，后者作反应细胞，进行混合细胞培养，建立小鼠心脏移植急性排斥反应体外模型。实验分4组：对照组，心肌细胞与脾细胞混合培养；3个实验组在对照组基础上，落新妇甙组加入落新妇甙（15μg/ml）；落新妇甙加P13K激动剂组加入落新妇甙（15μg/ml）和P13K激动剂IL-8（20μg/ml）；落新妇甙加P13K抑制剂组加入落新妇甙（15μg／ml）和P13K抑制剂LY294002（20μmol／L）。TUNEL法检测T淋巴细胞凋亡情况。Western blot法检测T细胞P13K和Bcl-2蛋白表达情况。RT-PCR法检测T细胞PKB mRNA表达情况。结果落新妇甙组T细胞凋亡指数明显高于对照组[（74．2±11．7）％对（34．2±9．6）％，P〈0．01]，P13K、PKB、Bcl-2表达显著低于对照组（P〈0．01）。落新妇甙加P13K抑制剂组T细胞凋亡指数显著高于落新妇甙组，P13K、PKB、Bcl-2显著低于落新妇甙组（P〈0．01）。落新妇甙加P13K激动剂组T细胞凋亡指数和Bcl-2表达与对照组的差异无统计学意义（P〉0．05）。结论落新妇甙诱导心脏移植效应性T细胞凋亡与其抑制PI-3K／PKB信号通路有关。     

干扰素-α诱导肾癌细胞胸苷磷酸化酶表达对5-FU化疗敏感性的影响

目的 探讨干扰素-α诱导肾癌细胞胸苷磷酸化酶（thymidine phosphorylase，TP）表达对5-氟尿嘧啶（5-FU）化疗敏感性的影响。方法采用不同浓度的干扰素-α2b处理肾癌细胞株786—0，应用RT—PCR和免疫印迹方法分别检测TP mRNA和TP蛋白水平变化。MTT法检测不同处理组786—0细胞中5-FU的半数抑制浓度（IC50）。建立肾透明细胞癌移植瘤动物模型，观察干扰素-α2b联合5-FU化疗对移植瘤生长的影响，免疫组化检测移植瘤中TP的表达，TUNEL检测肿瘤细胞的凋亡。结果 干扰素-α2b3000和6000IU／ml处理组，TP mRNA表达量（灰度峰值）分别为0．5733±0．0231和0．8233±0．0404，TP蛋白表达量分别为0．6347±0．0719和0．8735±0．0640。干扰素-α对TP的表达有剂量依赖性增强作用（P〈0．01）。在干扰素-α2b作用下，5-FU对786—0半数抑制浓度由（13．9467±3．7140）μmol／L下降至（5．3200±0．1039）μmol／L，化疗敏感性增加（P〈0．01）。联合用药组移植瘤体积为（0．0940±0．0492）cm^3，小于单纯5-FU组的（0．5424±0．1591）cm^3（P〈0．05）。单纯5-FU组和联合用药组移植瘤中肿瘤细胞凋亡指数差异无统计学意义（P〉0．05）。结论 干扰素-α2b诱导的TP增强表达参与了干扰素-α联合5-FU化疗增效作用，TP是干扰素-α2b的靶基因之。     

表现为急性胆囊炎的胆囊癌25例分析

目的：探讨老年人胆囊癌的临床特点，避免表现为急性胆囊炎的老年人胆囊癌行腹腔镜胆囊切除术。方法：回顾分析1995年1月-2005年12月表现为急性胆囊炎的老年患者（≥60岁）109例，其中术中或术后发现胆囊癌25例（均经病理证实），将此组患者与其余非肿瘤患者的术前临床资料包括术前肝功能等进行统计分析。结果：胆囊癌组25例，12例行剖腹探查，13例行腹腔镜手术。14例术中行快速冰冻切片示恶性而扩大手术或中转开腹，其余11例术后病理证实恶性肿瘤。非肿瘤组84例，34例行开腹手术，50例行腹腔镜手术，14例中转开腹。术前肿瘤组与非肿瘤组的肝功能变化有显著差异，主要为总胆红素TBil（83．4±131．2）μmol／L和（20．6±13．9）μmol／L，（P〈0．05）；直接胆红素DBil（55．1±77．4）tunol／L和（7．3±5．2）μmol／L，（P〈0．05）；AST（96．1±89．7）IU／L和（44．3±29．1）IU／L，（P〈0．05）；GGTP（512．1±871．8）IU／L和（99．8±101．3）IU／L，（P〈0．05）；AKP（433．7±272．5）IU／L和（98．7±47．4）IU／L，（P〈0．01）。结论：对于某些肝酶标异常的老年人急性胆囊炎，有胆囊癌可能。应进一步完善影像学检查，手术以直接开腹为宜。     

采用Edmonton免疫抑制方案的成人胰岛移植治疗1型糖尿病八例

目的：探讨成人胰岛移植治疗1型糖尿病的临床效果。方法：为8例1型糖尿病患者施行胰岛移植，供胰来自于成人尸体，消化、分离获得的胰岛培养过夜，然后经动脉插管输注至肝固有动脉，每例输注胰岛数为（8415±757）胰岛当量／kg，其中3例接受1个供者的胰岛移植，5例接受2个供者的胰岛移植（分2次进行）。8例患者中，除1例供、受者的ABO血型不同外，其余供、受者的ABO血型均相同。本组病例未行HLA配型。术后免疫抑制治疗采用Edmonton方案中的免疫抑制剂使用方法，即不使用类固醇激素，采用西罗莫司和他克莫司联用，并辅以5剂达利珠单抗。术后观察外源性胰岛素的使用量、血糖及血清C-肽的变化。结果：移植后平均随访7．7个月，2例完全停用胰岛素，5例的胰岛素用量减少47％～90％，1例效果不明显，胰岛素用量仅减少21％。8例血糖从移植前的（10．6±3．9）mmol／L降至（6．6±1．3）mmol／L，控制更为平稳；糖化血红蛋白A1从（11．9±1．6）％降至（5．9±1．2）％。移植有效者的血清C-肽基础值及葡萄糖刺激后C-肽水平分别由移植前的（0．054±0．076）nmol／L和（0．075±0．045）nmol／L升高至（0．620±0．080）nmol／L和（1．580±0．770）nmol／L。免疫抑制剂相关的并发症主要为白细胞减少（6例），减少或停用免疫抑制剂后白细胞可回升至正常，无大出血、门静脉栓塞或门静脉高压等并发症发生。结论：经肝动脉输注成人胰岛治疗1型糖尿病具有一定的临床效果，采用Edmonton免疫抑制方案安全、有效。     

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.     

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.     

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.