干细胞移植治疗大鼠后肢缺血中HIV-Tat-CLIO标记磁共振体内示踪的研究

目的 探讨人类免疫缺陷病毒tat蛋白转导域交连超顺磁氧化铁纳米颗粒(HIV-Tat-CLIO)标记、磁共振成像(MRI)无创体内示踪移植大鼠骨髓间充质干细胞(BMSC)的可行性和有效性.方法 SD人鼠28只,分为4组,每组7只,建立右后肢缺亦模型.A组移植HIV-Tat-CLIO标记的BMSC;B组移植HIV-Tat-CLIO与BrdU复合标记的BMSC;C组移植未标记的BMSC;D组注射无菌磷酸盐缓冲液(PBS).术后MRI示踪移植细胞,评估缺血改善程度,以及组织学检查.结果 B、C组分别死亡2只和1只.A、B组MRI结果相似:术后第3天,注射部位圆形低信号影,1周低信号灶离心性扩散成颗粒状,第2周低密度影进一步扩散,信号强度减弱,第4周信号强度进一步减弱,低密度颗粒扩散范围局限于原部位7 mm处.C、D组MRI阴性.缺血后肢平均皮肤温度、血管造影评分以及毛细血管密度A、B、C组间差异无统计学意义(P>0.05),均显著高于D组(P<0.05).D组的损伤评分明显高于其他3组,其他3组间差异无统计学意义.组织学检查与MRI结果一致.结论 HIV-Tat-CLIO标记、MRI可以有效地体内示踪植入大鼠缺血后肢的BMSC.对BM-SC改善缺血的效果无明显影响.     

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。     

热休克蛋白60诱导小鼠皮肤移植耐受的实验研究

目的探讨热休克蛋白60（heat shock protein60，HSP60）对小鼠移植皮片成活的影响及其机制。方法选用60只C57BL／6（H．2b）小鼠为受体，45只BALB／C（H．2d）小鼠、15只CBA／N（H-2^k）为供体，均为8～12周龄近交系雌性小鼠。受体小鼠剪下1cm&#215;1cm全层皮肤，干纱布清创，即为植床：随机分为4组，每组15只。A组：无菌取供体BALB／C（H．2d）小鼠背部1cm&#215;1cm全层皮片，刮去皮下组织后移植至受体小鼠背部；B组：受体小鼠背部皮下注射0．1mL不完全弗氏佐剂（imcompleted Freund’s adjuvant，IFA），2周后行BALB／C（H-2d）小鼠皮肤移植：C组：受体小鼠背部皮下注射经0．1mLIFA乳化后的50gtgHSP60，2周后行BALB／C（H-2^d）小鼠皮肤移植：D组：受体小鼠背部皮下注射经0．1mL IFA乳化后的50μg HSP60，2周后行CBA／N（H-2^k）小鼠皮肤移植。B、C、D组供体皮肤移植方法同A组。术后观察移植皮片成活时间；移植术后7、25d行单向混合淋巴细胞反应及混合淋巴细胞培养上清液细胞因子检测；术后7d行迟发型超敏反应测定。结果A、B、C、D组移植皮片成活时间分别为（12．4&#177;0．5）、（11．6&#177;0.8）、（29.3&#177;2．6）及（27．6&#177;2．1）d：A、B组与C、D组比较，差异有统计学意义（P〈0．05），A、B组间及C、D组间比较，差异无统计学意义（P〉0．05）。皮肤移植术后7d，A、B、C、D组混合淋巴细胞反应每分钟放射脉冲数（counts of perminute impulse，cmp）值分别为12836&#177;1357、11876&#177;1265、6581&#177;573及6843&#177;612；A、B组与C、D组比较，差异有统计学意义（JP〈0．05）：A、B组间及C、D组间比较差异无统计学意义（JP〉0．05）；术后25d，各组cpm值分别为13286&#177;1498、12960&#177;1376、11936&#177;1265及12374&#177;1269，各组间差异无统计学意义（P〉0．05）。皮肤移植术后7d，C、D组混合淋巴细胞培养上清液IL-10高于A、B组，IL-2、干扰素γ（interferonl，，IFN-γ）低于A、B组（JP〈0．05），A、B组间及C、D组间差异均无统计学意义（JP〉0．05）：术后25d，各组IL-2、IL-10及IFN-γ差异无统计学意义（P〉0．05）。皮肤移植术后7d，A、B、C、D组受体小鼠对供体小鼠脾细胞的迟发型超敏反应为（0．84&#177;0．09）、（0.81&#177;0．07）、（0．43&#177;0．05）及（0．46&#177;0．03）mm：A、B组与C、D组比较，差异有统计学意义（P〈0．05），A、B组间及C、D组间差异无统计学意义（P〉0．05）。结论HSP60对免疫耐受的诱导和维持有一定作用。     

大鼠锥体束损伤后多唾液酸神经细胞黏附分子的表达

目的 探讨大鼠脊髓锥体束损伤后多唾液酸神经细胞黏附分子（PSA-NCAM）的表达及意义。方法 Wistar大鼠60只，实验组（30只）毁损胸髓T10左侧锥体束，对照组（30只）未损伤脊髓。应用免疫组织化学和Western blot检测5-溴脱氧尿嘧啶（BrdU）、PSA-NCAM的表达。结果免疫组织化学染色：BrdU阳性细胞数，对照组（23．4±6．3），实验组在伤后第3天（93．1±7．6），第7天（65．1±8．6），组间差异有统计学意义（P〈0．05）；PSA-NCAM阳性细胞数，对照组（2．5±1．5），实验组在伤后第3天（82．1±11．4），第7天（31．1±5．2），组间差异有统计学意义（P〈0．05）；Western blot：蛋白表达组间差异有统计学意义（P〈0．01）。结论 锥体束损伤可激活自体室管膜细胞的增殖及迁移，后者具有一定的可塑性，参与脊髓的结构修复。     

小鼠脊髓损伤标准化重物打击模型的制备及评价

目的以小鼠作为实验动物，采用改良垂直打击脊髓（weight dropping，WD）建立脊髓损伤（spinal cord iniury，SCI）动物模型，为进一步研究SCI机制奠定基础。方法将健康雌性昆明种小鼠180只随机分为4组，每组45只，采用改良WD法应用Impactor model-Ⅱ脊髓致伤仪分别以2．0&#215;2．5g&#183;cm（A组）、2．5&#215;3．0g&#183;cm（B组）、3．0&#215;5．0g&#183;cm（C组）致伤力致伤脊髓；对照组（D组）仅打开椎板，暴露脊髓，不造成SCI。于打击后即刻，6、12h，1、3d，1、2、4、8周对各组小鼠行运动诱发电位（motor evoked potentials，MEP）检测，并行后肢运动功能（Basso mousescale，BMS）评分，HE染色和甲苯胺蓝染色组织学观察。结果神经电生理检查示B组于伤后6h，C组于伤后12h出现N1潜伏期延长，随着时间延长，A、B、C3组潜伏期开始缩短，A组4周趋于正常为（2．40&#177;0．12）ms，与D组比较差异无统计学意义（P〉0．05）；B组8周逐渐趋于正常为（2．96&#177;0．15）ms，与D组比较差异无统计学意义（P〉0．05），而C组8周仍维持在较高水平（3．76&#177;0．13）ms，与D组比较差异有统计学意义（P〈0．05）。SCI伤后即刻小鼠均呈现双后肢瘫痪，BMS主评分为0分；伤后前3dBMS主评分接近0分；随后各组BMS评分逐渐上升，A组伤后1周BMS主评分（5．45&#177;0．12）分，B组伤后2周BMS主评分为（5．45&#177;0．15）分，与D组比较差异均有统计学意义（P〈0．05）；伤后8周A组主评分（8．004&#177;0．13）分，B组达（7．50&#177;0.31）分；1周后各实验组组间比较差异均有统计学意义（P〈0．05），其中C组低于其余各组（P〈0．01）。伤后2周A组BMS副评分为（10．12&#177;0．76）分，伤后8周B组BMS副评分为（9．85&#177;0．55）分，与同时间点D组比较差异均无统计学意义（P〉0．05）。组织学检查可见C组伤后12h，损伤节段灰质内大片出血灶，炎性细胞浸润，神经元细胞肿胀明显，并出现中央性尼氏小体溶解；随时间推移，神经元细胞数量减少，胶质细胞增生，尼氏小体消失；伤后2周，可见大量胶质细胞增生及空洞形成。B组神经元细胞减少程度及空洞形成均轻于C组，A组最轻，D组除早期可见轻度细胞水肿外，整个观察期内细胞数量无明显改变。结论该模型准确地反映了小鼠脊髓不同程度损伤后的病理生理特点及变化规律，重复性好；可采用重物打击法制作标准小鼠SCI动物模型。     

嵌合体大鼠诱导异种皮肤移植免疫耐受的初步研究

目的 探讨嵌合体大鼠诱导异种皮肤移植免疫耐受的可行性。方法 采集兔骨髓干细胞，经行宫内胎鼠移植以及对新生子鼠行肝内注射，制作兔骨髓干细胞嵌合体大鼠模型。6周后将15只嵌合体大鼠分为A组（8只）、B组（7只）。将A组大鼠皮肤移植给供髓兔，将7只非嵌合体大鼠皮肤移植给非供髓兔作A组对照；将B组大鼠、7只非嵌合体大鼠（B组对照）皮肤同时移植给供髓兔。记录移植后皮片成活时间、创面愈合时间。结果A组对照移植皮片成活（9．3±1．8）d，创面于（20．9±2．1）d愈合；A组移植皮片成活（15．1±2．6）d，创面于（18．5±1．3）d愈合。B组及其对照移植皮片的成活时间、创面愈合时间与A组相似。与各自对照皮肤移植相比，A、B组皮片成活时间延长（P〈0．01），创面愈合时间缩短（P〈0．05或P〈0．01）。结论 嵌合体大鼠行异种皮肤移植后能诱导移植皮片免疫耐受．使其成活时间明显延长．创面愈合时间缩短。     

掌背侧不同入路钢板内固定治疗桡骨远端不稳定骨折

目的比较掌背侧不同手术入路内固定治疗桡骨远端不稳定骨折的疗效。方法2000年6月-2006年12月，收治桡骨远端骨折患者61例，男27例，女34例；年龄22～70岁，平均55．5岁。交通伤18例，跌伤43例。均为新鲜闭合骨折。术前均摄腕关节正、侧位X线片，30例行CT检查。按AO分型，B1型25例，B2型18例，B3型7例，C1型7例，C2型4例。随机分为两组，分别经腕掌侧（A组，n=34）及背侧（B组，n=27）入路切开行钢板内固定术。术前测量掌倾角和尺偏角，A组分别为（-145．0&#177;53．0）^o和（8．6&#177;3．1）^o，B组分别为（-40．0&#177;30．0）^o和（7．3&#177;5．6）^o。术前A、B组桡骨短缩分别为（12．0&#177;5．3）mm和（10．3&#177;4．2）mm；关节面台阶A组为（4．3&#177;2．2）min，B组为（4．1&#177;3．3）min。结果61例患者均获随访，随访时间6～27个月，平均16个月。骨折均愈合，A组愈合时间为（8．2&#177;1．6）周，B组为（8．1&#177;1．2）周，比较差异无统计学意义（P〉0．05）。腕关节功能采用Cartland-Werley评分，术后8周A组优7例，良10例，差17例，优良率为50．0％；B组优7例，良11例，差9例，优良率为66．7％；两组比较差异有统计学意义（P〈0．01）；术后24周，A组优21例，良9例，差4例，优良率为88．2％；B组优18例，良5例，差4例，优良率为85．2％；两组比较差异无统计学意义（P〉0．05）.放射学评估采用Sarmiento评分，术后测量掌倾角和尺偏角，A组分别为（9．5&#177;3．1）^o和（18．0&#177;8．2）^o,B组分别为（11．0&#177;4．7）。和（16．0&#177;7．6）^o术后两组均未见桡骨短缩；关节面台阶两组均〈1mm；所有指标A、B两组比较差异均无统计学意义（&#177;〉0．05）；与术前比较差异均有统计学意义（P〈0．001）。两组术后并发症比较，术后早期并发症差异无统计学意义（P〉0．05），术后远期并发症差异有统计学意义（P〈0．01）。结论掌背侧不同手术入路可为桡骨远端不稳定骨折提供有效复位及早期功能锻炼。掌侧入路钢板内固定术后早期腕关节旋前功能受影响，且远期并发症较多。     

移植肝细胞在倒千里光碱处理大鼠肝脏中增殖状态的研究

目的探讨移植肝细胞在倒千里光碱（RS）处理的大鼠肝脏中的增殖情况。方法将5-溴脱氧尿苷（BrdU）标记的肝细胞通过门静脉途径移植至RS或肝切除处理的大鼠肝脏中，通过免疫组织化学方法检测移植肝细胞数量及流式细胞仪检测S期细胞比率，从而了解供肝细胞在受体内的增殖。结果在接受RS和肝切除处理的大鼠肝脏中，移植的肝细胞数术后3、7、14、28d分别是41±4、67±4、154±10、248±23／1000个细胞，S期细胞比率分别是（4．37±0．21）％、（5．33±0．32）％、（9．55±0．72）％、（17．65±1．76）％，呈上升趋势。结论RS能够为移植肝细胞在受体内的增殖制造足够的增殖空间，在肝损伤造成的肝再生环境中，移植肝细胞的增殖更加显著。     

自体软骨细胞移植修复猪膝关节软骨缺损的实验研究

目的评价传统和复层高密度培养（复层培养）的自体软骨细胞移植修复关节软骨缺损的效果。方法在8头猪16膝髌切迹上下共建立32个全层软骨缺损，右膝为空白和自体骨膜移植对照组，左膝为传统的自体骨膜覆盖下细胞注射移植组和自体骨膜覆盖下复层培养细胞移植组（上下缺损随机进入各对照和实验组）。术后5-6个月对缺损部位行大体、组织学、免疫组织化学检查。采用O’Driscoll软骨组织形态学评分评价软骨缺损的修复质量。结果四组的O’Driscoll软骨组织形态学评分分别为（3．14±1．95）分、（10．57±3．60）分、（16．29±2．63）分、（20．43±1．81）分，各组之间差异均有统计学意义（P〈0．01）。空白对照组缺损被少量的纤维组织覆盖；骨膜移植组被纤维组织和少量的纤维软骨修复，且与周围组织整合差。自体软骨细胞移植（注射组和复层培养组）缺损被塑形良好的修复组织覆盖，组织学、基质特殊染色示修复组织为纤维软骨和透明软骨，与周边软骨和软骨下骨整合良好。复层培养组修复组织的细胞形态、基质染色比注射细胞组更接近正常软骨。结论自体软骨细胞移植可成功修复全层关节软骨缺损。扩增后的软骨细胞经短期复层培养更有利于软骨缺损的修复。     

烧伤残余创面的序贯性治疗

目的寻找烧伤残余创面序贯性治疗的有效方法。方法选择烧伤残余创面患者25例，采取自身对照，分别以凡士林油纱（A组）、组织工程全层皮肤（HTAS，B组）覆盖创面，用含氧液冲洗、负压引流后覆盖HTAS（C组）。取创面标本检测细菌量、肿瘤坏死因子（TNF）α含量及基质金属蛋白酶（MMP）13mRNA表达水平，计算创面愈合率。结果治疗后第3、6、9、12天，患者C组创面细菌量分别为（5．30±1．60）、（1．30±0．80）、（1．70±0．60）和（0．60±0.10）集落形成单位（CFU）／ml，显著低于A、B组（P＜0．01）。C组创面经治疗后6d，TNF-α．含量和MMP-13mRNA表达水平分别为（0．650±0．040）ng／mg、0．210±0．010，明显低于A组[（1．550±0．370）ng／mg、1．040±0．050，P＜0．01]和B组[（0．810±0，080）ng／mg、0．640±0．030，P＜0．01]；B组肉芽组织TNF-α含量和MMP-13mRNA表达量显著低于A组（P＜0．01）。治疗后15、30d，C组创面愈合率明显高于A、B组（P＜0．01）。结论应用含氧液冲洗、负压引流后覆盖HTAS，可显著促进创面愈合，是一种有效的烧伤残余创面序贯性治疗方法。     

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.