氨等离子体锚定短肽的消旋聚乳酸骨支架研究

目的运用氨等离子体辅助接枝技术,在消旋聚乳酸(poly-D,L-lactide acid,PDLLA)表面以酰胺键接枝甘氨酸-精氨酸-甘氨酸-天冬氨酸-丝氨酸(Gly-Arg-Gly-Asp-Ser,GRGDS)短肽,探讨制备活性骨替代材料的可行性。方法使用溶剂浇铸/颗粒沥析法制备圆片状直径8mm、厚1mm的PDLLA三维骨支架,行氨等离子体改性处理制备表面氨基化PDLLA(aminated PDLLA,A/PDLLA),测量未改性(0min对照组)及改性5、10、20min组支架的孔径、孔隙率和表面水接触角。以上各组A/PDLLA放入1mg/mLFITC标记的GRGDS肽溶液[1-(3-二甲基氨基丙基)-3-乙基碳化二亚胺盐酸盐、N-羟基琥珀酰亚胺、活性肽的摩尔比值为1.5:1.5:1.0],室温下低速震荡24h行表面接枝处理,得到接枝肽处理材料(peptides conjugated A/PDLLA,PA/PDLLA)。对未改性(0min对照组)、改性5、10、20min及其后接枝肽处理的材料行X射线光电子能谱(X-rayphotoelectron spectroscopy,XPS)仪检测;对PDLLA和改性0、5、10、20min后接枝肽处理的材料行激光共聚焦显微镜观察及高效液相色谱(high performance liquid chromatography,HPLC)定量分析。全骨髓贴壁法分离、培养SD大鼠BMSCs,取第3～6代细胞接种于以下3组材料:20min氨等离子体改性组(A/PDLLA组)、20min氨等离子体改性后接枝肽组(PA/PDLLA组)及未经处理的PDLLA对照组(PDLLA组)。各组BMSCs-材料复合物培养16h后测定细胞上架数及上架率;培养4、8d行扫描电镜观察。结果 PDLLA孔径和孔隙率不随氨等离子体改性时间变化而变化(P0.05)。随着氨等离子体改性时间延长,A/PDLLA支架表面水接触角逐渐减小,材料亲水性能逐步改善,各组间比较差异均有统计学意义(P0.001)。XPS检测示,A/PDLLA支架表面出现N元素,且随改性时间延长,N1s峰渐趋明显,N/C逐渐加大;PA/PDLLA支架N/C相应加大,表面出现S2p峰。激光共聚焦显微镜观察示PA/PDLLA支架荧光强度随改性时间延长而明显增强。HPLC成功测得经10min和20min氨等离子体改性后接枝肽处理的PA/PDLLA接枝肽量,两者比较差异有统计学意义(P0.001);而PDLLA及经0、5min氨等离子体改性后接枝肽处理的PA/PDLLA接枝肽量未检出。与BMSCs复合培养16h,A/PDLLA组和PA/PDLLA组细胞上架数和上架率均高于PDLLA组,3组间两两比较差异均有统计学意义(P0.01)。扫描电镜观察示,A/PDLLA组和PA/PDLLA组比PDLLA组更能促进BMSCs贴附增殖,尤以PA/PDLLA组最明显。结论氨等离子体改性能明显促进PDLLA表面以酰胺键接枝FITC-GRGDS短肽;此仿生人工骨材料生物活性稳定,能明显促进BMSCs贴附和增殖。     

不同血清对成人骨髓基质干细胞成骨诱导分化的影响

[目的]探讨三种不同来源血清对体外培养成人骨髓基质干细胞(hBMSCs)向成骨诱导分化的作用.[方法]将体外第3代hBMSCs向成骨诱导分化培养,分为胎牛血清组(对照组)、AB 血清组和自体血清组.对比观察细胞碱性磷酸酶(ALP)染色、钙结节染色.诱导培养后4、7、14 d 和 21 d,各血清组分别进行钙黄绿素法荧光显微镜动态观察矿盐沉积,检测 ALP 活性,实时荧光定量 PCR(RT-qPCR)法检测成骨基因(ALP)、骨桥蛋白(OPN)和骨钙素(OCN)的表达.[结果]ALP 染色和钙结节染色结果显示,与自体血清(AS)组、胎牛血清(FBS)组相比,AB 血清(ABS)组明显提高了 hBMSCs 的染色阳性率.荧光显微镜下观察诱导 21 d 的 hBMSCs,ABS 组较 FBS 组、AS 组呈现更多的钙盐沉积.ALP 活性结果显示,同一时间点 ABS 组的 ALP 活性均明显高于 FBS 组和 AS 组,差异有统计意义(P<0.05).RT-qPCR 结果显示,在7、14 d 和 21 d,ABS 组 ALP、OPN 和 OCN 成骨基因表达均明显高于 FBS 组、AS 组,其中,ALP 基因表达在 7 d 出现峰值,OPN 基因表达在 14 d 出现峰值,OCN 基因表达在 21 d 出现峰值,差异均有统计学意义(P<0.05).[结论]ABS 对 hBMSCs 成骨分化作用较 FBS、AS 明显增强.ABS 有望替代 FBS 建立符合骨组织工程临床应用要求的体外 hBMSCs 培养体系.     

GLP-1对GK糖尿病大鼠骨髓间充质干细胞骨向分化能力的影响

目的 观察胰高血糖素样肽-l( Glucagon-like peptide-I,GLP-l)对Goto-Kakizaki鼠骨髓间充质干细胞（Bone marrow stromal cell,BMSCs)成骨分化能力的影响,并讨探其可能作用机制。方法 贴壁法取8周龄GK鼠BMSCs,逆转录PCR法验证BMSCs表达GLP-1受体,MTT法筛选GLP-1对GK鼠BMSCs的最佳刺激浓度,选取该浓度干预GK鼠BMSCs,观察其成骨分化相关指标：第7 d、14 d测定碱性磷酸酶活性,第14d应用实时定量PCR检测ALP、RUNX2、OCN、Smad1、β-catenin、OPG和 RANKL的表达。结果 1. GK鼠BMSCs中存在GLP-1受体;2. 20 nmol/L的GLP-1对细胞刺激作用最佳;3.成骨诱导后ALP 活性升高。成骨诱导7 d,诱导组和GLP-1干预组的ALP活性相对于对照组均明显升高(P <0. 05);成骨诱导14 d,诱导组和 GLP-1干预组的ALP活性进一步升高（与自身7d时相比,P <0.05),且均高于对照组(P <0. 05); GLP-1干预组ALP活性在第 7d时稍高于诱导组(P >0. 05),第14d时明显高于诱导组(P <0. 05) ;4.与正常成骨诱导组相比,GLP-1干预组ALP和RUNX 2表达量均明显增加(P <0.5),OCN的表达量增加,但无统计学意义。GLP-1干预组表达Smad1减少（P > 0. 05),β-catenin 明显增多（P <0.05)。GLP-1干预组表达 OPG增加（P >0.05),RANKL 减少（P <0. 05),OPG/RANKL 升高（P <0.05)。结论 1. GK鼠BMSCs上存在GLP-1受体;2. GLP-1可促进GK鼠BMSCs向成骨细胞分化,并调节Wnt通路部分基因的表达及OPG/RANK/RANKL轴的动态平衡。     

含锶羟基磷灰石浸提液诱导骨髓基质干细胞成骨分化的研究

目的 探讨含锶羟基磷灰石(Sr-HA)对骨髓基质干细胞(BMSCs)成骨分化的影响.方法 从2只SD雄性大鼠双侧股骨、胫骨提取BMSCs.用含锶量分别为摩尔百分比为10%Sr-HA(A组)、5%Sr-HA(B组)、1% Sr-HA(C组)及不含锶的HA(D组)生物陶瓷粉末制备浸提液培养大鼠BMSCs.在培养的1、3、5、7、10 d检测各组BMSCs的增殖情况,于诱导培养后6、9、12及15 d检测各组BMSCs的碱性磷酸酶(ALP)活性,于诱导培养后3、6、9及12 d检测各组BMSCs的核心结合因子α1(Cbfα1)基因表达.结果 A、B、C、D组细胞培养1、3、5、7、10 d四甲基偶氮唑盐(MTT)检测结果显示:各组间吸光度值差异均无统计学意义(P＞0.05),但同一组内不同时间点的吸光度值差异均有统计学意义(P＜0.05).细胞培养6 d时A、B、C、D组的ALP活性OD值分别为(0.061±0.005)、(0.058±0.003)、(0.056±0.005)、(0.055±0.005),从6 d起A组和B组ALP活性均显著高于C、D组,差异有统计学意义(P＜0.05).细胞培养9和12 d时各组Cbfα1 mRNA相对表达量两两比较差异均有统计学意义(P＜0.05).结论 HA中含锶量对BMSCs增殖无明显影响,但能促进BMSCs的成骨分化.     

绝经后骨质疏松症病人骨髓间充质干细胞STIM1与成骨分化关键因子的表达变化

目的探讨绝经后骨质疏松症病人骨髓间充质干细胞(BMSCs)基质交感分子1(STIM1)与成骨分化关键因子碱性磷酸酶(ALP)、骨桥蛋白(OCN)、骨钙素(OPN)的表达变化情况。方法通过临床取材获得并培养绝经后骨质疏松症病人BMSCs,加入成骨诱导液孵育14天,采用RT-PCR检测ALP、OPN、OCN的转录水平及ALP的活性,并检测STIM1的表达情况。采用ALP染色法检测ALP活性;采用Alizarin Red染色法检测钙结节形成数量;采用Fluo荧光法检测钙离子内流变化。结果通过无菌培养,获得高纯度绝经后骨质疏松症(观察组)病人的BMSCs,经成骨诱导14天后,观察组病人BMSCs中成骨分化关键因子ALP、OPN、OCN的转录水平以及ALP的活性均低于对照组(P0.05),同时STIM1 mRNA的表达水平也相应下降,钙离子内流较对照组减少(P0.05)。另外,观察组病人BMSCs钙结节形成数量少于对照组。结论绝经后骨质疏松的发病机制可能与由STIM1参与调控的钙释放激活钙离子通道开放情况密切相关,可作为绝经后骨质疏松病人预防和治疗的潜在靶点。     

组织界面刚度变化对大鼠BMSCs成骨分化的影响

目的探讨组织界面刚度变化对大鼠BMSCs铺展、增殖和成骨分化的影响,寻找适合其成骨分化的刚度范围。方法取4周龄SPF级雄性SD大鼠骨髓,采用全骨髓细胞贴壁法分离培养BMSCs并鉴定。取第3代BMSCs,按1×10~5个/mL密度接种于覆盖弹性模量分别为1、4、10、40、80 kPa聚丙烯酰胺水凝胶(polyacrylamide hydrophilic gel,PA)的普通培养皿(细胞接种于PA基底上),普通培养皿(弹性模量75 MPa)作为对照,光镜下观察细胞在不同刚度PA上的铺展状态。选取4、10和40 kPa PA覆盖作为研究对象(分别为A、B、C组),以普通培养皿为对照组(D组),细胞计数检测BMSCs生长情况,ALP试剂盒检测BMSCs的ALP浓度,茜素红染色法检测BMSCs的钙沉积状况,实时荧光定量PCR检测BMSCs的骨钙素(bone gla protein,BGP)、Runx2、Ⅰ型胶原mRNA表达。结果随着PA刚度的提升,BMSCs铺展面积增加,尤其在10、40 kPa PA上铺展较好。生长曲线示,培养1、2 d各组间细胞增殖情况差异无统计学意义(P0.05),3~5 dB、C组增殖情况明显优于A、D组(P0.05),5 d时C组显著高于B组(P0.05)。A、B、C、D组ALP浓度分别为(53.69±0.89)、(97.30±1.57)、(126.60±14.54)、(12.93±0.58)U/gprot,A、B、C组显著高于D组,C组高于A、B组,差异均有统计学意义(P0.05)。茜素红染色示,C组钙结节百分比为20.07%±4.24%,显著高于A、B、D组,差异有统计学意义(P0.05)。实时荧光定量PCR检测示,A、B、C组BGP、Ⅰ型胶原m RNA相对表达量均高于D组,C组高于A、B组,差异均有统计学意义(P0.05)。B、C组Runx2 mRNA相对表达量高于D组,C组高于B组,差异均有统计学意义(P0.05);A、D组间差异无统计学意义(P0.05)。结论 10~40 kPa范围的PA能促进大鼠BMSCs增殖及成骨分化,刚度越高,作用越强。     

低温保存对人骨髓基质干细胞在脱钙骨上体外增殖及成骨能力的影响

目的研究低温保存对人骨髓基质干细胞(BMSCs)在脱钙骨(DBM)上生长特性及成骨能力的影响。方法取3例志愿者骨髓(3～5mL),密度梯度离心、差速贴壁法获得BMSCs。第3代BMSCs在-196℃下保存24h,37℃复苏,测定细胞成活率。低温保存前、后的BMSCs分别用成骨诱导液诱导培养,至90%融合时,收集细胞接种在DBM支架上,并测定细胞在DBM上的粘附率。DiI荧光染料标记BMSCs,例置相差显微镜、荧光显微镜和SEM观察低温保存前、后的BMSCs在DBM上的生长及基质分泌情况,MTT法测定细胞在DBM上的增殖活性。通过测定碱性磷酸酶(ALP)活性和骨钙素(OCN)含量观察细胞在DBM上的成骨能力。结果复苏细胞的存活率为(90．24±0．02)%。低温保存前、后的BMSCs在DBM上的粘附率分别为(97．25±1．17)%和(97．00±1．09)%。倒置相差显微镜及SEM观察显示低温保存前、后的BMSCs在DBM上粘附、生长良好,有大量细胞外基质分泌、沉积。低温保存前、后的BMSCs在DBM上MTT吸光度值和ALP活性的检测结果差异无显著性意义(P＞0．05)；体外培养12d时,MTT吸光度值及ALP活性同时达到峰值。低温保存前、后的BMSCs在DBM上分泌OCN的量差异无显著性意义(P＞0．05),OCN含量随着培养时间延长而不断上升,在观察期(16d)内未出现平台期。结论低温保存对人BMSCs在DBM上的体外增殖、粘附及成骨能力影响差异无显著性意义,低温保存的人BMSCs可作为组织工程骨的种子细胞。     

联合转染人VEGF165和ANG-1双基因对大鼠骨髓基质干细胞成骨分化的影响

[目的]研究联合转染入血管内皮细胞生长因子165(VEGF165)和血管紧张素-1(ANG-1)双基因对大鼠骨髓基质干细胞(BMSCs)成骨分化潜能的影响.[方法]将本室构建的编码人VEGF165和ANG-1双基因腺病毒质粒pAd-VIA在QBI-293A细胞内进行包装和扩增,获得腺病毒载体pAd-VIA,将其体外转染大鼠BMSCs,应用诱导培养液定向诱导向成骨细胞分化.实验分为4组:A.腺病毒载体pAd-VIA转染BMSCs并诱导组;B.BMSCs诱导组;C.腺病毒载体pAd-VIA转染BMSCs组;D.单纯BMSCs组.通过碱性磷酸酶(ALP)染色和活性的测定、Ⅰ型胶原免疫荧光染色、茜素红染色来评价联合转染双基因对BMSCs成骨分化潜能的影响.[结果]重组腺病毒质粒pAdVIA在QBI-293A细胞内成功包装和扩增,有大量的绿色荧光蛋白表达,体外转染大鼠BMSCs后,A、B组的ALP染色、Ⅰ型胶原免疫荧光染色、茜素红染色为阳性,而C组和D组为阴性.ALP活性表达具有时间相关性,3 d开始表达,7 d到达高峰,在7、14 d,A、B组与C、D组之间ALP表达均具有统计学差异(P＜0.01),A组和B组之间,在各个时间点均无统计学差异(P＞0.05).[结论]腺病毒载体pAd-VIA转染大鼠BMSCs后,未明显影响其体外成骨分化潜能.     

辛伐他汀通过p38MAPK信号通路诱导BMSCs成骨分化的研究

目的观察辛伐他汀(SIM)体外单独给药对大鼠骨髓间充质干细胞(BMSCs)成骨分化的影响。方法取第二代大鼠BMSCs随机分为4组,对照组(CM):完全培养基培养;诱导组(OM):成骨诱导培养基培养;辛伐他汀组(SIM):含终浓度为10-7mol/L的辛伐他汀的完全培养基培养;阻断剂组(SB+SIM):先用p38MAPK通路阻断剂SB203580干预30min后,加入等浓度辛伐他汀。给药4 h后,Western Blot检测p-p38MAPK、p38MAPK蛋白的表达。给药7d后,进行碱性磷酸酶(ALP)染色和比活性测定。给药7、14d后,采用Real-time PCR法检测ALP、Ι型胶原(COLΙ)、骨钙素(OCN)和Runt相关转录因子2(Runx2)m RNA的表达。结果 1Western Blot检测:OM组和SIM组p-p38MAPK表达水平显著高于CM组和SB+SIM组(P0.05)。2ALP比活性测定:OM组和SIM组显著高于CM组,与相比,SB+SIM组显著低于SIM组(P0.05)。3ALP染色:OM组和SIM组细胞胞浆内出现棕色颗粒,而SB+SIM组和CM组未见明显阳性染色颗粒。4Real-time PCR检测:在第7d、14d,OM组和SIM组ALP、COLΙ和Runx2 m RNA表达水平均显著高于CM组,SB+SIM组明显低于SIM组(P0.05);第7d,OM组OCN m RNA表达水平明显高于CM组(P0.05);在第14d,OM组和SIM组OCN m RNA表达水平高于CM组,SB+SIM组低于SIM组(P0.05)。结论辛伐他汀可以在缺乏成骨诱导成分的环境下,通过活化p38MAPK信号诱导大鼠BMSCs向成骨细胞分化。     

透明质酸对BMP-2转染的羊BMSCs增殖、分化的影响

目的观察透明质酸（HA）对携带人骨形态发生蛋白-2的腺病毒（Adv-BMP-2）转染的羊骨髓基质干细胞（BMSCs）体外增殖、分化的影响。方法将羊骨髓体外分离、扩增BMSCs,分成5组：转染Adv-BMP-2的BMSCs＋HA组（Ⅰ组）,转染Adv-BMP-2的BMSCs组（2组）,BMSCs＋HA组（3组）,BMSCs组（4组）,转染携带β半乳糖苷酶的腺病毒（Adv-β-gal）的BMSCs组（5组）。采用细胞计数、绘制细胞生长曲线和流式细胞分析观测细胞增殖;采用碱性磷酸酶（ALP）检测以及RT-PCR检测Ⅰ型胶原（Col-Ⅰ）、骨连接素（ON）和骨涎蛋白（BSP）的mRNA表达。结果①细胞增殖：3 d后各组细胞增殖无显著差异,1周后第1组和第3组的细胞增殖明显高于其他组。②ALP活性：3 d后第3组ALP活性明显低于第4、5组,而第1、2组则显著高于第4、5组;7 d后前3组ALP活性较后两组均显著增加,而第1、2组ALP活性增加更为显著。③Col-Ⅰ、ON和BSP的mRNA表达：3 d和7 d后前3组较后两组均有不同程度的增多。结论HA与BMSCs体外复合培养后可促进BMSCs的增殖、增加ALP的活性以及Col-Ⅰ、ON和BSP基因的表达。     

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.