血红素氧合酶-1对移植的异种心脏的保护作用

目的探讨血红素氧合酶-1(HO-1)对移植的异种心脏的保护作用及其可能机制。方法应用NI H小鼠到Wistar大鼠颈部异位心脏移植模型,术前对供者分别用HO-1的诱导剂CoPP或HO-1的阻滞剂ZnPP进行处理,术后受者相应接受CoPP或ZnPP处理,部分受者同时接受环孢素A(CsA)处理,并设空白对照组和单用CsA组。分别用免疫组化、逆转录聚合酶链反应、Westernblot蛋白印迹杂交等检测移植心组织中HO-1、HO-1mRNA、凋亡蛋白酶-3以及信号传导与转录因子-3(STAT-3)的表达,测定心肌组织中HO-1的活性,采用原位末端标记法检测心肌细胞凋亡情况,比较不同处理因素之间的差异。结果单一接受CoPP者(CoPP组)移植心脏存活时间长于空白对照组及单一接受ZnPP者(P<0.01),但短于同时接受CoPP和CsA处理者(CoPP CsA组,P<0.01);CoPP组及CoPP CsA组HO-1、HO-1mRNA的表达及HO-1的活性均高于其余各组(P<0.01),其心肌细胞凋亡数和凋亡蛋白酶-3低于其余各组(P<0.05),而STAT-3高于其余各组(P<0.01)。结论CoPP诱导产生的HO-1可延长NI H小鼠到Wistar大鼠异种移植心脏的存活时间,该作用可能与STAT-3激活、凋亡蛋白酶-3受抑制而导致心肌细胞凋亡发生率下降有关。     

同种异基因造血干细胞移植急性移植物抗宿主病小鼠模型的制作

目的 制作同种异基因造血干细胞移植急性移植物抗宿主病(GVHD)小鼠模型.方法 以C57BL/6( H-2b)小鼠为供者,Balb/c( H-2d)小鼠为受者,进行同种异基因骨髓移植.设立全身照射(TBI)对照组(4只)、GVHD组(10只)、单纯骨髓移植组(10只)及正常对照组(4只).TBI对照组仅进行致死性TBI,TBI后不进行骨髓移植;GVHD组于TBI前5d开始饮用含320 mg/L庆大霉素和250 mg/L红霉素的饮用水,移植当天以60Co γ射线行一次性TBI,总剂量8.0Gy,TBI后5h内每只小鼠经尾静脉输注C57BL/6小鼠骨髓细胞2×106个+脾细胞1×107个;单纯骨髓移植组预处理与GVHD组相同,每只小鼠经尾静脉输注C57BL/6小鼠骨髓细胞2×106个.移植后观察小鼠的精神状态、活动能力、体位改变、皮毛、体重和大便等,记录每只小鼠的存活时间,计算存活率,并绘制生存曲线.濒死小鼠的皮肤、肝脏、小肠和骨髓行病理检查.结果 TBI对照组小鼠的存活时间为(9.0±0.7)d,GVHD组为(32.0±3.2)d,单纯骨髓移植组为(17.5±1.6)d,3组间两两比较,存活时间的差异均有统计学意义(P＜0.01).TBI对照组病理检查显示造血功能衰竭.GVHD组于移植后第10～13天出现急性GVHD表现,其皮肤、肝脏和小肠组织的病理表现均符合Ⅰ～Ⅱ度急性GVHD改变,单纯骨髓移植组也于移植后第10～13天出现GVHD表现,但其GVHD表现和组织学改变明显轻于GVHD组,仅为0～Ⅰ度GVHD.结论 Balb/c小鼠经致死性TBI后移植同种异基因小鼠骨髓细胞+脾细胞可成功制作稳定的急性GVHD模型.     

HSCT联合不同剂量内皮祖细胞输注对小鼠造血重建的影响

目的 探讨异基因造血干细胞移植联合不同剂量内皮祖细胞(EPC)输注对移植后造血重建的影响.方法 以C57BL/6小鼠为供鼠,Balb/c小鼠为受鼠,进行HSCT,输注骨髓单个核细胞数量为5×106个/只.仅进行HSCT者为单纯骨髓细胞移植组;行HSCT的同时经尾静脉输注供者骨髓单个核细胞诱导培养的EPC的受鼠为EPC联合移植组,EPC的输注量分别为5×104、1×105、5× 105和1×106个/只.另设正常对照组和致死量照射组.观察小鼠的存活率、造血重建情况及骨髓微环境的变化.结果 各EPC联合移植组小鼠存活时间长于单纯骨髓移植组,5×105 EPC联合移植组至观察结束时存活率为100％,高于其他各组(P＜0.05).移植后10和15 d,5×105 EPC联合移植组外周血白细胞数量高于其他组(P＜0.05).移植后15 d,5×105 EPC联合移植组外周血血小板数量高于其他组(P＜0.05).5×105 EPC联合移植组造血组织增生程度也好于其他组.5×105 EPC联合移植组骨髓内HSC比例为(1.06±0.03)％,高于其他各组(P＜0.05).结论 小鼠异基因骨髓移植中联合输注5×105 EPC能够有效促进造血重建,提高小鼠存活率.     

骨髓移植小鼠急性移植物抗宿主病早期弥漫性肺损伤中TH17细胞的作用

目的 探讨骨髓移植小鼠急性移植物抗宿主病(aGVHD)早期肺损伤中TH 17细胞的作用和机理.方法 Balb/c小鼠为受鼠,经致死量全身照射(TBI)后,输注C57BL/6小鼠来源的骨髓细胞和脾细胞,建立aGVHD模型.实验分为3组:TBI组小鼠仅接受TBI,异基因骨髓移植(BMT)组小鼠TBI后输注供者骨髓细胞和脾细胞,常山酮(HF)组小鼠TBI后输注骨髓细胞和脾细胞,并注射HF.动态观察小鼠GVHD的表现,并进行肺组织病理学、T淋巴细胞亚群及相关细胞因子的检测.结果 移植后小鼠出现典型GVHD的表现.移植后6d时HF组肺组织病理学评分为(2.00±0.35)分,BMT组为(0.67±0.07)分.BMT组TH 1细胞占CD4+T淋巴细胞的比例为(5.53±0.11)％,TH 17细胞占(1.04±0.34)％;HF组TH1细胞占(8.61±0.21)％,TH 17细胞占(0.49±0.07)％;组间比较,差异有统计学意义(P＜0.05).两组均未检测到TH2细胞.移植后6d,BMT组白细胞介素(IL)-17A为(2.81±0.19)pg/ml,γ干扰素(IFN-γ)为(42.97±0.23) pg/ml; HF组IL-17A＜0.8 pg/ml,IFN-γ为(9.89±0.51)pg/ml;组间比较,差异有统计学意义(P＜0.05).两组均未检测到IL-10.结论 在异基因造血干细胞移植早期阻断TH17细胞及其细胞因子的分泌,导致炎症因子分泌失衡,加重肺损伤.     

钴原卟啉诱导血红素氧化酶-1表达上调对异种移植胰岛的保护作用

目的 研究不同浓度钴原卟啉(CoPP)与其诱导胰岛细胞血红素氧化酶-1(HO-1)表达的效应关系,探讨HO-1表达上调对异种移植胰岛的保护作用.方法 将分离和纯化的供者胰岛随机分为5组(A、B、C、D和E组),分别置于含有不同摩尔浓度CoPP的培养液中诱导,5组CoPP的浓度依次为0、5、25、50和75 mmol/L.检测各组胰岛细胞中HO-1mRNA和HO-1蛋白表达情况,并测定体外胰岛素释放水平,筛选出能诱导HO-1表达上调幅度最高的CoPP合适浓度.再将受者分为研究组和对照组(每组8只),对照组移植未经CoPP诱导的供者胰岛细胞;研究组移植经合适浓度CoPP诱导的供者胰岛细胞,术后每天监测受者血糖和排斥反应情况.结果 D组HO-1mRNA、蛋白表达上调幅度以及胰岛素分泌量均高于其他4组,差异均有统计学意义(P＜0.05),诱导胰岛细胞HO-1上调幅度最高的CoPP浓度为50 mmol/L.研究组受者移植D组供者胰岛后,维持正常血糖的时间为(14.63±1.19)d,对照组为(9.88±2.17)d,两组比较,差异有统计学意义(P＜0.01).结论 在异种胰岛移植中,经50 mmol/L的CoPP体外诱导供者胰岛HO-1表达上调幅度最高;HO-1的表达上调可以促进移植胰岛的功能恢复,抑制排斥反应,延长移植胰岛的存活时间.     

输注鼠基因工程Treg细胞抑制小鼠异基因骨髓移植后移植物抗宿主病

目的 探讨输注慢病毒载体介导的鼠基因工程调节性T淋巴细胞(Treg细胞)对小鼠异基因骨髓移植后移植物抗宿主病(GVHD)的影响.方法 利用慢病毒载体介导,将鼠又状头螺旋转录因子(Foxp3)基因转导入Balb/c小鼠的CD4~+ CD25~-T淋巴细胞,即为基因工程Treg细胞.以Balb/c小鼠为供者,C57BL/6小鼠为受者,进行异基因骨髓移植,实验分4组进行:(1)工程Treg组经受鼠尾静脉输注供鼠骨髓细胞5×10~6个+脾细胞5×10~6个+基因工程Treg细胞5×10~6个;(2)移植对照组经受鼠尾静脉输注供鼠骨髓细胞5×10~6个+脾细胞5x10~6;(3)单纯照射组经受鼠尾静脉输注RPMI 1640培养液0.2ml;(4)空载体对照组经受鼠尾静脉输注供鼠骨髓细胞5×10~6个+脾细胞5×10~6个十空载体转导的CD4~+ CD25~-T 淋巴细胞5×10~6个.每天观察受鼠存活情况;记录GVHD的发生情况;各组均于小鼠濒死前取其肝脏、小肠、皮肤等组织,进行病理学观察;取长期存活(超过60d)的受鼠骨髓细胞,检测嵌合情况.结果 单纯照射组、移植对照组、工程Treg组和空载体对照组小鼠存活时间分别为(8.8±0.6)d、(36.7±2.5)d、(51.6±4.0)d和(34.1±2.3)d,工程Treg组小鼠存活时间明显长于其他各组,差异有统计学意义(P<0.05).移植对照组及空载体对照组小鼠肝脏、皮肤和小肠病理切片均存在GVHD病理改变,工程Treg组长期存活小鼠的肝脏、皮肤和小肠常规病理切片结构基本正常,未见GVHD病理表现,该组GVHD评分明显低于移植对照组及空载体对照组.结论 小鼠异基因骨髓移植时联合输注基因工程Treg细胞可有效减少GVHD的发生,减轻其严重程度.     

减低强度预处理造血干细胞移植联合低剂量环孢素A治疗恶性血液病

目的 探讨以减低强度的氟达拉滨、白消安(Bu)和环磷酰胺(CTX)为预处理方案的异基因外周血造血干细胞移植(HSCT)联合低剂量环孢素A(CsA)的疗效及并发症发生情况.方法 恶性血液病患者11例,接受同胞间HSCT,供、受者问HLA配型,HLA全相合10例.5个抗原相合1例.预处理包括移植前第9～4天给予氟达拉滨30～35 mg·m-2·d-1,移植前第4、3天给予白消安3.2 mg·kg-1·d1,移植前第2、1天给予CTX 60mg·kg1·d-1.移植后联合使用CsA和短程甲氨蝶呤(MTX)预防移植物抗宿主病(GVHD),供者细胞植入后,降低CsA用量.结果 移植后早期11例造血功能均获得重建,骨髓细胞为完全供者型.随访3～17个月,9例并发急性GVHD,主要侵犯肝脏和皮肤;9例并发慢性GVHD,均侵犯口腔和肝脏,其中1例为广泛性慢性GVHD,其余为局限性慢性GVHD.增加CsA用量或者加用甲泼尼龙后,急、慢性GVHD均能得到控制,仅1例需加用霉酚酸脂.11例中,2例的原发病复发,其中1例病情得到控制,1例失访.结论 HSCT时采用氟达拉滨、白消安和环磷酰胺(CTX)预处理方案,并将白消安的用量减为常用剂量的一半,移植后采用低剂量CsA,细胞的植入率高;急、慢性GVHD的发生率较高,但对糖皮质激素和CsA的治疗反应良好.     

诱导供者胰岛细胞高表达血红素加氧酶-1延长大鼠胰岛移植物的存活时间

目的 探讨钴原卟啉(CoPP)诱导大鼠胰岛细胞高表达血红素加氧酚1(HO-1)后,对延长胰岛移植物存活时间的作用.方法 (1)将分离和纯化的供者(BN大鼠)胰岛细胞分为CoPP诱导组和未诱导组.CoPP诱导组供者在分离胰岛细胞前3天和前1天腹腔注射2.5 mg/kg的CoPP,未诱导组不注射CoPP.诱导后,采用免疫荧光法及Western免疫印迹法检测两组胰岛细胞中HO-1的表达情况,采用酶联免疫吸附试验(ELISA)和葡萄糖刺激试验检测胰岛细胞的胰岛素释放水平.(2)Lewis大鼠经四氧嘧啶静脉注射后建立糖尿病模型,取10只成功建立糖尿病模型的大鼠作为胰岛细胞移植的受者,随机平均将受者分为实验组和对照组,分别移植经CoPP诱导和未经诱导的供者胰岛细胞.移植后,观察和比较两组受者胰岛移植物的存活时间和发生排斥反应后胰岛移植物的组织病理学变化.结果 CoPP诱导组胰岛细胞高表达HO-1,而未诱导组不表达HO-1;CoPP诱导组和未诱导组供者胰岛细胞胰岛素分泌量,在低糖刺激下分别为(15.65±0.89)mU/L和(12.28±0.89)mU/L(P>0.05),在高糖刺激下分别为(46.60±1.13)mU/L和(19.01±1.49)mU/L(P<0.05),刺激指数分别为2.98±0.10和1.55±0.01(P<0.05).实验组和对照组胰岛移植物平均存活时间分别为(12.20±5.67)d和(5.60±1.14)d(P<0.05);当受者发牛排斥反应时,对照组胰岛移植物周边可见明显的淋巴细胞、成纤维细胞以及单个核细胞浸润,而实验组细胞浸润的程度明显较轻.结论 CoPP可诱导大鼠胰岛细胞高表达HO-1,其对胰岛细胞有明显保护作用.移植高表达HO-1的胰岛细胞能显著延长胰岛移植物的存活时间.     

钴原卟啉诱导血红素氧合酶-1高表达减轻大鼠肾脏缺血再灌注损伤

目的 探讨钴原卟啉(CoPP)诱导血红素氧合酶-1(HO-1)高表达对大鼠肾脏缺血再灌注损伤(IRI)的影响及其机理.方法 以Wistar大鼠为实验对象,CoPP组分别于左肾血流阻断前48 h和24 h腹腔注射CoPP 2.5 mg/kg,然后阻断左肾血流47 min,恢复左肾血流的同时切取大鼠右肾,采用免疫组织化学染色和免疫印迹法检测其HO-1的表达.在再灌注24 h后,处死大鼠,取其下腔静脉血和左肾,测定血肌酐(Cr)和尿素氮(BUN)浓度,观察肾组织学变化,检测肾组织中HO-1的表达.IRI组除不用CoPP处理外,其余同CoPP组.CoPP组和IRI组另有部分大鼠的血流阻断时间延长至80 min,恢复血流后不处死,观察14 d,记录其存活情况.结果 IRI组血清Cr及BUN分别为(134.37±24.26)μmol/L和(30.10±3.09)mmol/L,明显高于CoPP组的(48.92±12.92)μmol/L和(13.99±5.00)mmol/L(P＜0.05).IRI组肾小管细胞大片坏死,管型形成,与之相比,CoPP组肾小管坏死范围稍小,但肾小管病变范围仍较广泛,肾小管上皮细胞多处于水变性阶段,"缺血样"肾小球减少,管型形成较少.缺血前及再灌注24 h后,CoPP组的肾组织中HO-1均为高表达,主要位于肾间质的毛细血管处,IRI组再灌注24 h后也见肾组织中HO-1为高表达.术后14 d内,IRI组的6只大鼠中有4只死亡,而CoPP组的5只大鼠全部存活,两组大鼠存活率的差异有统计学意义(P＜0.05).结论 缺血前使用CoPP可减轻大鼠肾脏缺血再灌注损伤,该保护作用可能是通过CoPP诱导肾脏高表达HO-1来实现的.     

输注供者自然杀伤细胞对小鼠单倍型相合造血干细胞移植的影响

目的 探讨输注供者自然杀伤(NK)细胞对小鼠单倍型相合造血干细胞移植的影响.方法 选取C57BL/6(H-2b)雄性小鼠为供者、CB6F1(H-2d/b)雌性小鼠为受者.移植前制备供者的骨髓细胞(BMC)、脾细胞(SC)及脾NK细胞,NK细胞经体外培养扩增和激活;所有受者均接受直线加速器X线全身照射(TBI)预处理.TBI后将受者分为4组(每组10只),分别进行单倍型相合造血干细胞移植.单纯TBI组:TBI后不输注细胞,仅作为对照;单纯BMC输注组:输注5×106个BMC;诱发GVHD组:输注5×106个BMC+1.5×107个SC;NK细胞输注组:输注5 x 106个BMC+1.5×107个SC+1×107个NK细胞,并腹腔注射100 ng重组人白细胞介素2(rhIL-2)和1μg rhIL-15,持续7 d.移植后观察各组受者GVHD的发生情况,并对各组受者进行组织病理学、供者细胞嵌合度和免疫功能重建等检测.另取TBI后受者20只,设白血病复发组和白血病治疗组,每组10只.白血病复发组:输注5×106个BMC+1×107个SC+2×106个白血病细胞株EL9611;白血病治疗组:在白血病复发组的基础上再输注1 x 107个NK细胞,并腹腔注射100 ng rhIL-2和1μg rhIL-15,持续7 d.观察两组受者白血病复发情况和移植后100 d的存活率.结果 单纯BMC输注组受者无GVHD发生,NK细胞输注组受者GVHD的评分和组织病理学改变均较诱发GVHD组轻(P<0.05)f诱发GVHD组的免疫功能重建较NK细胞输注组延迟.白血病复发组和白血病治疗组移植后100 d的存活率分别为20%和90%,两组比较,差异有统计学意义(P<0.01).结论 输注激活的供者NK细胞可以减轻小鼠单倍型相合造血干细胞移植后的GVHD,减少白血病复发,促进免疫功能重建.     

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.