强直性脊柱炎与非炎性髋关节疾病行人工全髋关节置换术的围手术期炎症指标比较

目的探讨强直性脊柱炎(ankylosing spondylitis,AS)行人工全髋关节置换术(total hip arthroplasty,THA)围手术期炎症指标的变化规律,并与非炎性髋关节疾病比较,评价炎性活动是否影响术后炎症指标的变化及增加并发症发生。方法回顾分析2013年1月-2014年12月明确诊断为AS并行初次THA的153例患者,根据髋关节活动度(range of motion,ROM)将患者分为强直组(ROM 0°;A组,92例)和僵直组(ROM 3~46°;B组,61例);随机选取120例同期行THA且术前炎症指标C反应蛋白(C-reactive protein,CRP)、IL-6、红细胞沉降率(eryt hrocyte sedimentation rate,ESR)处于正常范围、住院期间未发生感染的非炎性髋关节疾病患者作为非炎性疾病组(C组)。分别于术前及术后1、3、5、7 d检测血清CRP、I L-6、ESR变化情况,并观察并发症发生情况。结果组内比较:3组患者血清CRP、IL-6及ESR均呈先升高后下降的趋势。术后各时间点CRP、ESR与术前比较差异均有统计学意义(P0.05);术后1、3、5 d IL-6高于术前(P0.05),但术后7 d与术前比较差异无统计学意义(P0.05)。组间比较:除术前B组CRP、IL-6、ESR高于A组,术前及术后1 d A、B组CRP、IL-6高于C组,以及术前及术后1、3 d A、B组ESR高于C组(P0.05)外,其余各时间点各组间CRP、IL-6、ESR比较差异均无统计学意义(P0.05)。所有AS患者术后均未出现炎性活动或并发症增加的情况。结论 AS与非炎性疾病的炎症指标手术前后变化趋势相似;AS的炎性活动对术后炎症指标的变化无明显影响,也未增加术后并发症的发生。     

快速交换球囊扩张导管技术制备兔急性脊髓压迫损伤模型

目的 :探讨快速交换球囊扩张导管技术制备兔单纯脊髓压迫损伤模型的可行性。方法 :将24只新西兰大白兔随机分为3组,麻醉成功后备皮,以T10为中心取背部正中切口,长约4cm,显露T8~T11,假手术组(A组)行T8一侧椎板切除,不置入球囊;对照组(B组)将T8一侧椎板切除后置入球囊达T10水平,不扩张球囊;实验组(C组)行T8一侧椎板切除后,将球囊通过T8置入达T10水平,将球囊快速充起,占据椎管前后径约30%,术中采用CT平扫确定球囊位置并记录球囊扩张达到占位程度时的压强值并维持此压强值压迫48h。术前和术后48h行体感诱发电位(SSEP)检查并记录图形和数值变化,采用改良Tarlov评分记录各组术后48h动物后肢活动情况。同时记录各组兔术后1d、2d体重下降值和饮食量。术后2d各组随机选取5只实验兔取出以T10为中心脊髓组织进行病理学检查,每组剩余3只均以T8为中心上下约0.5cm范围进行拆线,B、C组将球囊内压力减为负压后将球囊轻轻抽出,最后缝合切口,继续观察并记录术后4d、7d、14d时体重下降值及饮食量。结果:C组造模球囊扩张达到椎管前后径30%占位程度时球囊内压强为67.23±22.34k Pa,95%置信区间为(48.55~85.91)k Pa。造模术后C组SSEP波幅显著性降低,与A、B组术后及C组术前比较均有统计学差异(P0.05),A组与B组比较差异无统计学意义(P0.05)。造模后48h改良Tarlov评分A组(6.00±0.00分)与B组(5.88±0.35分)比较差异无统计学意义(P0.05),A、B组与C组(1.13±0.35分)比较差异均有统计学意义(P0.05)。术后1d、2d、4d、7d、14d时3组兔体重下降值及饮食量均无统计学差异(P0.05),术后14d时体重恢复至正常体重,术后7d时饮食恢复正常。结论:快速交换球囊扩张导管技术制备兔单纯脊髓压迫损伤模型可模拟临床急性脊髓压迫损伤的状态。     

损伤控制手术治疗兔脊髓压迫性损伤的效果

目的:探讨损伤控制手术(damage control operation)治疗兔脊髓压迫性损伤的效果。方法:应用球囊压迫法制备新西兰大白兔脊髓压迫损伤模型45只,造模术后2d随机取5只完成行为学观测、评分后取出损伤区脊髓组织进行流式细胞仪凋亡细胞检测、病理学观察、免疫组化染色检测兔损伤区脊髓组织中基质金属蛋白酶2(MMP-2)表达(对照组),剩余40只随机分为两组,每组20只,一组采用损伤控制手术(A组),即减压术前先将球囊内压力减为原来一半,使椎管内有效容积增加后再自远离脊髓压迫较重的一侧进行全椎板减压;另一组直接予全椎板切除减压,减压自压迫最严重部位开始(B组),两组减压完毕后均取出球囊,并在减压术后1d、3d、7d、14d分别随机取5只实验兔完成以上检测内容。结果:对照组造模术后48h的Tarlov评分为1.20±0.45分,A、B组减压术后1d时Tarlov评分与对照组比较均无统计学差异(P0.05);A、B组减压术后1d、3d、7d时的Tarlov评分均无统计学差异(P0.05),减压术后14d时A组高于B组(P0.05)。对照组脊髓细胞凋亡率为(2.66±1.40)%,A、B组减压术后1d时脊髓细胞凋亡率均低于对照组(P0.05);减压术后1d、3d时A、B两组损伤区脊髓细胞凋亡率无统计学差异(P0.05);A、B组减压术后1d与3d、7d与14d损伤区脊髓细胞凋亡率无统计学差异(P0.05);A、B组减压术后3d与7d损伤区脊髓细胞凋亡率均有统计学差异(P0.05);减压术后7d、14d时A组损伤区脊髓细胞凋亡率均低于同时间点B组(P0.05)。病理学观察显示对照组白质轻度脱髓鞘、部分轴突空泡样变,灰质内细胞水肿,A、B组减压术后1d、3d、7d、14d白质弥漫性脱髓鞘改变及散在点状出血,灰质内细胞水肿伴神经细胞变性逐渐加重,至减压术后7d时灰质内广泛神经细胞变性,并持续到术后14d。对照组MMP-2表达阳性细胞率为(45.76±0.75)%,A、B组减压术后1d时MMP-2表达阳性率均低于对照组(P0.05);减压术后1d、3d、7d、14d时B组MMP-2表达阳性细胞率均高于同时间点A组(P0.05),A、B组减压术后1d、3d比较均无统计学差异(P0.05),3d、7d,7d、14d比较均有统计学差异(P0.05)。结论:损伤控制手术治疗兔脊髓压迫性损伤较直接减压效果好,建议对胸腰椎爆裂骨折合并脊髓压迫损伤的治疗采用损伤控制手术方案。     

复合HRZ/PLGA缓释抗结核药涂层材料在兔脊柱结核病灶释药研究

目的 :观察复合HRZ/PLGA缓释抗结核药涂层材料在兔脊柱结核病灶的释药特性。方法 :应用兔脊柱结核模型120只,按三联抗痨药异烟肼(INH,H)、利福平(RFP,R)和吡嗪酰胺(PZA,Z)给药剂型及途径不同,随机分为4组(各30只):A组(复合HRZ/PLGA缓释材料局部给药组);B组(局部给药组);C组(灌胃给药组);D组(假手术灌药组)。其中A、B、C三组行L4/5脊柱结核病灶清除及自体髂骨植骨术,D组行假手术。采用高效液相色谱(HPLC)检测术后3d、7d、14d、28d、56d、84d各组病灶骨组织中H、R及Z的浓度,绘制药物浓度-时间曲线;使用DAS 3.2.1统计软件对药动学参数进行分析。结果:A组病灶骨组织中H、R及Z的浓度均在术后3d时达最高,此后随检测时间点的后移三种药物浓度均逐渐下降,至给药后84d时最低(H为6.69±1.42μg/ml;R为6.28±0.77μg/ml;Z为19.88±0.90μg/ml),三种药物浓度在各检测时间点均≥10倍的MIC(即杀菌浓度),对同种药物在不同时间检测的浓度进行两两比较,均有统计学意义(P0.05);B组病灶骨组织中H、R及Z的浓度在术后3d时均明显增高,此后较快衰减,至给药后14d时三种药物浓度均检测不到,对同种药物在3d与7d检测的浓度进行比较,差异有统计学意义(P0.05);C组及D组随检测时间点的后移,病灶骨组织中H、R及Z的药物浓度均维持在相对平稳的较低水平,对同组中同种药物在不同时间检测的浓度进行两两比较均无统计学意义(P0.05),术后84d检测时C组H为3.21±0.32μg/ml、R为3.68±0.42μg/ml、Z为6.68±0.25μg/ml,D组H为3.24±0.33μg/ml、R为3.53±0.44μg/ml、Z为6.39±0.45μg/ml。对A、B、C、D四组同时间点同种药物浓度进行比较:C、D两组间同时间点同种药物浓度比较均无统计学差异(P0.05);A组病灶骨组织中H、R及Z的浓度均高于C组及D组的浓度,84d检测时A组中的H、R及Z的浓度分别为C组的3.02、1.70及2.97倍,差异有统计学意义(P0.05);A、C、D三组药物浓度-时间曲线平缓,均未见突释现象;B组存在明显突释现象,药物浓度衰减较快,术后14d后检测不到H、R及Z的浓度。药动学数据分析:A组的曲线下面积、生物半衰期均显著高于B组及C组,差异有统计学意义(P0.05)。结论:复合HRZ/PLGA缓释抗结核药涂层材料在兔脊柱结核病灶局部可实现三药同时长程、高效、平缓释药。     

复合三联抗结核药涂层材料(HRZ/PLGA)在大鼠体内释药特性观察

目的:观察复合异烟肼(H)、利福平(R)、吡嗪酰胺(Z)三联抗结核药的聚乳酸-羟基乙酸(PLGA)涂层材料(HRZ/PLGA)在大鼠体内的释药特性。方法:将84只成年SD大鼠随机分为A、B、C三组,每组28只。A组为复合抗结核药HRZ/PLGA涂层材料植入组;B组为抗结核药HRZ植入组;C组为空白未载药PLGA涂层材料植入组,于术后1d、3d、1w、2w、4w、6w、8w时分别麻醉各组大鼠4只,抽取腹腔静脉血液5ml,处死后取体内植入材料或药物周边1cm的肌肉组织,应用高效液相色谱法(HPLC)检测肌肉组织及血清中H、R、Z三种药物的浓度,并于1w、4w时取血检测肝、肾功(AST、ALT、Ur、Cr),2w及6w时取植入局部肌肉组织进行形态学观察。结果:A组在术后3d时HRZ/PLGA涂层材料周边肌肉组织中三药浓度均达最高,2w后药物浓度下降趋势平稳,8w时H、R、Z三药平均浓度分别为0.87、0.92、1.61μg/g,均能达到各自10倍最低抑菌浓度(MIC);B组在术后3d时植入HRZ周边肌肉组织中三药物浓度均达最高,但药物浓度下降较快,4w时三种药物均不能检测到;C组不能检测到三种药物。A组肌肉检测药物浓度曲线较B组明显平稳、长程。A组静脉血中三种药物浓度明显低于植入HRZ/PLGA涂层材料周边的肌肉组织(P0.05)。术后1w、4w时各组AST、ALT、Ur、Cr与术前比较差异均无统计学意义(P0.05)。2w时A组及C组植入局部肌肉组织HE染色观察镜下见炎症细胞及PLGA降解产生空泡存在,6w时炎症细胞及空泡减少,A、B、C三组未见明显细胞坏死。结论:HRZ/PLGA涂层材料在SD大鼠体内释药平稳,持续时间较长,可实现体内局部用药的有效缓释;直接植入体内后组织生物相容性及可塑形性良好,为脊柱结核病灶清除后复合自体骨的局部有效给药提供了新方法。     

医用臭氧对膝骨关节炎兔软骨基质金属蛋白酶-1的影响

目的 探讨医用臭氧对膝骨关节炎兔软骨基质金属蛋白酶-1(MMP-1)的影响.方法 新西兰大白兔30只,体重2.2～2.8 kg,雌雄不拘,并以左膝关节作为对比,随机分为3组,每组10只,建立右膝骨关节炎(OA)模型,分别于造模成功后第3天和第5天向右膝关节腔内注入空气(A组)、40μg/L(B组)和80 μg/L(C组)医用臭氧3 ml.造模成功后第7天处死动物,取两膝关节,光镜下观察关节软骨一般形态,甲苯胺蓝染色行Mankin评分;免疫组化法检测软骨基质金属蛋白酶-1(MMP-1)的表达水平;分别于造模成功时和处死前即刻测定兔两膝关节活动度.结果 与左膝关节比较,各组造模成功时右膝关节活动度降低,软骨组织Mankin评分、软骨细胞MMP-1表达升高(P＜0.05);B组和C组处死前即刻右膝关节活动度较造模成功时升高(P＜0.05).与A组比较,B组软骨组织Mankin评分、软骨细胞MMp-1表达降低(P＜0.05);与B组比较,C组上述指标升高(P＜0.05).A组和C组软骨明显退变,程度重于B组.结论 关节腔内注射40 μg/L医用臭氧3ml治疗兔膝骨关节炎的机制可能与下调软骨MMP-1有关.     

3种入路手术治疗胸椎结核的疗效

目的回顾性分析前后路联合手术以及前路、后路手术治疗胸椎结核的疗效。方法 84例胸椎结核患者(病灶≤2个节段),根据手术入路的不同分为A组(前路手术)、B组(后路手术)和C组(前后路联合手术),每组28例。比较3组患者的手术时间、术中出血量、红细胞沉降率(ESR)、C-反应蛋白(CRP)水平、Cobb角情况以及术后并发症。结果 84例患者均随访1年。手术时间、术中出血量C组明显短(少)于A组和B组(P 0. 05)。术后3个月及末次随访时ESR、CRP、Cobb角3组均明显低于术前(P 0. 05),C组均明显低于A组和B组(P 0. 05)。3组术后并发症发生率比较差异无统计学意义(P 0. 05)。结论 3种入路手术治疗胸椎结核均取得较好疗效。相较于前路、后路手术治疗,前后路联合手术治疗的临床效果更为满意。     

雷洛昔芬对兔骨折愈合的影响

目的 研究雷洛昔芬(raloxifene,RLX)对兔骨折愈合的影响.方法 健康新西兰大白兔80只,雌性44只,雄性36只,体重1.9～2.1 kg.取72只动物制备左前肢桡骨中段0.5 cm骨缺损模型,按给药不同分为4组,每组18只(雌性10只,雄性8只).A、B、C组分别于术后第2天给予7.5、15.0、30.0mg/(kg·d)RLX至50d,D组不作处理.剩余8只不作任何处理,作为血清骨钙素检测正常对照.于术后不同时间点行骨密度、生物力学测定、X线片组织学和免疫组织化学染色观察,测定血清雌二醇、血浆胆固醇含量、血清骨钙素水平及子宫干重/体重比.结果 术后20 d各组骨密度达峰值,A、B、C组骨密度均高于D组(P＜0.05);但A、B、C组间差异无统计学意义(P＞0.05).术后30、50 d,A、B、C组最大破坏载荷和最大位移均较D组大(P＜0.05);A、B、C组间差异无统计学意义(P＞0.05).术后7、20、30d,A、B、C组骨折X线评分较D组高(P＜0.05);50 d时B、C组与D组间及A、C组间比较差异均有统计学意义(P＜0.05),B、C组间差异无统计学意义(P＞0.05).术后30、50 d,A、B、C组骨折愈合处新骨面积百分比均高于D组(P＜0.05).术后30d,B、C组骨折愈合处Col Ⅱ蛋白分泌较D组增多(P＜0.05),A、D组差异无统计学意义(P＞0.05);50 d时各组间差异均无统计学意义(P＞0.05).术后10、30及50 d各组血清骨钙素水平均较正常对照动物明显增高(P＜0.05);B、C组均较D组高(P＜0.05);A组与D组比较,A、B、C组间比较差异均无统计学意义(P＞0.05).术后30 d,各组血浆胆固醇含量无明显变化(P＞0.05);50 d时A、B、C组均明显降低,与D组比较差异有统计学意义(P＜0.05).术后30、50 d,B、C组血清雌二醇含量与D组比较差异有统计学意义(P＜0.05),余各组间比较差异无统计学意义(P＞0.05).术后30、50d,B、C组子宫干重/体重小于D组(P＜0.05),A、D组差异无统计学意义(P＞0.05).结论 以7.5 mg/(kg·d)剂量口服RLX可安全有效促进兔桡骨缺损骨折模型骨折愈合.     

纳米羟基磷灰石/聚酰胺66复合物椎间融合器在山羊颈椎融合中的应用

目的:观察纳米羟基磷灰石/聚酰胺66复合物(n-HA/PA66)椎间融合器在山羊颈椎前路融合中的效果。方法:15只成年雌性山羊随机分成A、B、C组,每组5只,均行经前路C3/4椎间盘切除术,A组椎间置入n-HA/PA66椎间融合器植骨;B组置入钛网植骨;C组采用自体三面皮质髂骨块植骨。分别于术前、术后、术后4周、8周及12周拍X线片观察测量各组手术节段平均椎间高度(disc space height,DSH)、椎间角(intervertebral angle,IVA)及前凸角(lordosis angle,LA);12周时处死动物取颈椎标本进行生物力学测试及组织学检查。结果:术前三组DSH、IVA和LA无显著性差异。术后即刻及术后4周三组间DSH无显著性差异(P0.05);术后8周及12周,A组DSH与B、C组有显著性差异(P0.05);B组和C组差别无显著性(P0.05)。术后即刻及术后4周、8周三组间IVA无显著性差异(P0.05);术后12周,A、B组IVA与C组有显著性差异(P0.05),A组与B组无显著性差异。术后即刻及术后4周、8周三组间LA差异无显著性(P0.05);术后12周,A、B组LA与C组有显著性差异(P0.05),B组与C组无显著性差异。术后12周时,A、B组颈椎标本各向角位移与C组有显著性差异(P0.05);除后伸外A组各向稳定性优于B、C组;平均刚度均强于B、C组;ROM均小于B、C组(P0.05)。A组在植骨区和椎间融合器边缘可见大量成熟的骨小梁组织,材料交界处可见大量纤维骨痂及新生骨形成,骨组织与材料表面已发生嵌合;B组的植骨块与椎体间的新生骨小梁已改建为成熟的骨小梁,部分区域尚可见未完全矿化的类骨质;C组可见较多的纤维骨痂形成,在骨小梁表面有红色的类骨质,部分区域有成熟的骨小梁。结论:n-HA/PA66椎间融合器能有效维持椎间隙高度,促进山羊颈椎前路植骨融合。     

罗西格列酮对脊髓损伤大鼠神经功能恢复的作用及机制

目的:观察罗西格列酮对脊髓损伤(SCI)大鼠后肢运动功能恢复的作用,探讨其作用机制。方法:75只成年SD大鼠,应用Allen改良法制作大鼠T10SCI模型,随机分为A、B、C三组,每组25只,B、C组于损伤后5min、6h、24h腹腔注射罗西格列酮,C组在腹腔注射罗西格列酮前1h给予G3335,A组于相应时间点腹腔注射等体积生理盐水作为对照组。每组取6只大鼠于伤后1d、7d、2w、4w、6w时对后肢运动功能进行BBB评分;伤后3d每组取4只动物脊髓组织行免疫组织化学染色法检测核转录因子κB(nuclear factor kappa-light-chain-enhancer of activated B cells,NF-κB)的表达;伤后1、3、5、7d和2w每组取3只应用Westernblot法检测脊髓组织中凋亡相关蛋白caspase-3和Bcl-2的表达。结果:伤后1d、7d时3组大鼠BBB评分均为0分,伤后2w开始B组BBB评分高于A组和C组,4w和6w时与A、C组比较有显著性差异(P0.05);伤后3d时三组NF-κB表达均为阳性,但B组平均光密度值明显低于A、C组(P0.05),B组与C组比较无显著性差异(P0.05);伤后各时间点B组caspase-3表达量均低于A组和C组(P0.05),而Bcl-2表达均高于A组和C组(P0.05),其差异均在伤后5d达到高峰,A组与C组同时间点比较无显著性差异(P0.05)。结论:罗西格列酮可促进SCI大鼠神经功能恢复,其机制可能与抑制炎症反应及细胞凋亡有关。     

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.     

Is the recovery profile of mivacurium independent of the rate of decay of its plasma concentration in patients with normal plasma cholinesterase activity?

Background: The duration of action of muscle relaxants is poorly correlated to the rate of decay of their plasma concentration. The plasma concentration of mivacurium may rapidly decrease below its active concentration because of the extensive hydrolysis of mivacurium. By inflating a tourniquet on one upper limb for 3 min after the administration of atracurium, mivacurium or vecuronium, we studied the influence of the initial decline of their plasma concentration on their effect. Methods: In 50 patients anaesthetised with thiopental, isoflurane and fentanyl, the effect of bolus doses of 0.15 or 0.25 mg . kg^?1 mivacurium (MIV 15, MIV 25), 0.3 or 0.5 mg . kg^?1 atracurium (ATR 30, ATR 50) and 0.06 or 0.1 mg . kg^?1 vecuronium (VEC 06, VEC 10) were measured on both arms (evoked response of the adductor pollicis to train-of-four stimulation every 12 s), a tourniquet being applied on one arm just before and during 3 min after the muscle relaxant bolus. Results: Tourniquet inflation of 3 min almost abolished the neuromuscular effect of mivacurium. In the vecuronium groups and in the ATR 50 group, tourniquet inflation did not modify the maximum degree of depression of the twitch response. Also, the duration of action of vecuronium was unaffected by the tourniquet. In the ATR 30 group, times to return of the twitch response to 25% (duration 25%) and 75% (duration 75%) of control response were significantly shorter in the cuffed arm, 23 min vs 27 min, and 41 min vs 45 min, respectively. In the ATR 50 group, only duration 25% was significantly shorter in the cuffed arm (41 min vs 45 min). Conclusion: The results suggest that the rate of decline of the plasma concentration of mivacurium is so rapid, that a very low and almost clinically ineffective concentration is present as soon as 3 min after its administration. The results also indicate that the recovery from a mivacurium-induced neuromuscular blockade is not influenced by the rate of decay of its plasma concentration in patients with genotypically normal plasma cholinesterase.     

Membranes in Artificial Organs

Abstract: Membrane processes play a pivotal and enabling role in modern replacement therapy for acute and chronic organ failure and in the management of immunologic diseases. In fact, virtually all contemporary extracorporeal blood purification methods employ membrane devices, and the next generation of artificial organs and tissue engineering therapies are almost certain to be similarly grounded in membrane technology. In this short essay, we comment on the similarities and differences among synthetic membranes and their natural counterparts and also provide a critical overview of the demographics and technology of hemodialysis, hemofiltration, apheresis, oxygenation, and emerging membrane technologies and applications.     

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.     

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.     

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.     

Dilemma of Membrane Biocompatibility and Reuse

Abstract: Numerous articles have been published on the multiple use of dialyzers and on the effect of different reprocessing chemicals and techniques on the dialyzer biocompatibility and performance. The results often appear contradictory, especially those comparing standard biocompatibility parameters. Despite this confusion, a discerning review of the published works allows certain limited conclusions to be drawn. Reprocessing of used hemodialyzers changes the biocompatibility profile of a dialyzer as defined by the parameters complement activation. leukopenia, and cytokine release. The effect of reprocessing depends on the chemicals and reprocessing technique applied and also on the type of membrane polymer being subjected to the reprocessing procedure. Reports of pyrogenic reactions indicate that the flux of the membrane also influences how suitable it is for safe reuse. An increased risk of allergic and pyrogenic reactions appears to be associated with dialyzer reuse. Furthermore, there has been a lack of investigations into the immunologic effect of the layer of adsorbed and chemically altered proteins that remains on the inner surface of reprocessed dialyzers. We conclude that the clinical benefit of dialyzer reuse cannot be generally accepted from a biocompatibility point of view.     

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.