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.     

联合内皮祖细胞移植对小鼠骨髓移植预处理中肝脏内皮损伤的修复作用

目的 研究联合内皮祖细胞(EPC)移植对小鼠骨髓移植预处理中肝脏内皮损伤的修复作用.方法 将C57BL/6小鼠分为4组,每组10只.(1)正常对照组:小鼠不做任何处理,仅作为正常对照;(2)单纯照射组:单次给予全身照射(TBI)预处理,不进行骨髓移植;(3)单纯移植组:给予单纯照射组相同的TBI预处理,TBI后4 h内经小鼠尾静脉输注C57BL/6小鼠骨髓单个核细胞5×106/只;(4)联合移植组,小鼠的处理方式与单纯移植组相同,仅在骨髓移植的同时经尾静脉输注C57BL/6小鼠EPC 5×105/只.TBI后第2、4、7、14、21天,检测各组小鼠肝脏重量的变化情况,并于TBI后第4、7、14、21天对各组小鼠肝脏进行组织病理学检查.结果 单纯照射组、单纯移植组和联合移植组小鼠肝脏重量均于TBI后第2天开始明显增加,于第14天达到高峰,峰值分别为正常对照组的(1.65±0.15)倍(P＜0.05)、(1.61±0.06)倍(P＜0.05)和(1.11±0.4(0)倍(P＜0.05);以后均呈下降趋势,第21天时单纯照射组和单纯移植组肝脏重量仍明显高于正常对照组(P＜0.05),但联合移植组小鼠肝脏重量已完全恢复正常.组织病理学检查显示,单纯照射组小鼠肝窦内皮损伤明显,肝细胞水肿及严重的炎症细胞浸润,第7天时肝细胞水肿、坏死较前明显加重,几乎无存活的肝血窦内皮细胞;第14天时单纯移植组小鼠肝窦内皮损伤较前有所减轻,但到第21天时仍未恢复正常;联合移植组小鼠第7天时肝窦内皮及肝细胞水肿、坏死程度均较轻,到第14天时已基本恢复正常.结论 造血干细胞移植前的预处理会造成受者肝脏内皮损伤,且此损伤持续存在;移植时联合输注EPC能修复肝窦内皮的损伤.

Abstract：

Objective To study the repair function of united endothelial progenitor cells (EPC)transplantation on injured liver endothelium by bone marrow transplantation (BMT) conditioning.Methods C57BL/6 mice were divided into four groups randomly: normal control group, without any treatment; irradiation alone group, administered a total body irradiation(TBI) pretreatment, without BMT; (3) BMT alone group: C57BL/6 mice were infused with bone marrow mononuclearcells (MNC) 5 × 106/only through caudal vein not more than 4 h after the same TBI pretreatment as the irradiation alone group; united transplantation group: receiving the same way as the BMT alone group, but C57BL/6 mice were infused with EPC 5 × 105/only at the same time. Two, 4, 7, 14, and 21 days after the TBI, the changes of the liver weight were observed regularly. The histopathological examination of liver was done at the 4th, 7th, 14th, and 21st day after the TBI. Results In irradiation alone group, BMT alone group and united transplantation group the liver weight began to increase significantly on the day 2 and peaked at 14th day after the TBI, and the peaks were respectively (1.65±0. 15) times (P＜0. 05), (1.61 ±0.06) times (P＜0.05), and (1.11 ±0.40)times (P＜0. 05) of those in normal control group. At the day 14, the liver weight in irradiation alone group, BMT alone group and united transplantation group began to decrease, and on the day 21 the liver weight in united transplantation group had been completely restored to normal level, however the liver weight in irradiation alone group and BMT alone group were still significantly heavier than that in normal control group (P＜0. 05). Liver histopathological examination revealed that there were obvious sinusoidal endothelial cells (SEC) injury, hepatocyte edema and severe inflammatory cell infiltration in irradiation alone group, and on the day 7 the hepatocyte edema and necrosis were significantly worse than before, and almost no alive SEC were found. On the day 14 the injury of SEC in BMT alone group was lighter than before, but on the day 21 the injury had not returned to normal. On the day 7 the injury of SEC, hepatocyte edema and necrosis were alleviated in united transplantation group as compared with irradiation alone group and BMT alone group, and on the day 14 the injury had returned to normal basically. Conclusion The transplantation conditioning could damage recipient liver endothelium and the injury would persist, and united EPC infusion could repair the injured SEC following BMT.     

骨髓移植后肝静脉闭塞病模型的鉴定及机制探讨

目的 建立异基因骨髓移植后肝静脉闭塞病(HVOD)模型并探索其发生机制.方法 将Balb/c小鼠随机分为3组,即生理盐水对照组(NS组)、单纯照射组和单纯骨髓移植组.于移植后第0、5、10、15和20天检测各组小鼠肝重、外周血胆红素总量(TBil)以及外周血肿瘤坏死因子α(TNF-α)、白细胞介素6(IL-6)和单核细胞趋化因子-1(MCP-1)浓度的变化,小鼠肝脏组织病理学改变.结果 小鼠肝重和TBil均于骨髓移植后第5天开始升高,第15天达到高峰.骨髓移植第5、10天小鼠肝脏以充血、水肿变化为主,肝组织存在炎症细胞浸润;第15、20天小鼠肝脏充血、水肿及坏死减轻,以肝脏纤维化为主要表现,炎症浸润明显.单纯照射组小鼠照射后10 d内全部死亡,肝脏充血、水肿严重.与NS组小鼠相比较,单纯骨髓移植组小鼠TNF-α、IL-6和MCP-1浓度明显升高.结论 成功建立异基因骨髓移植后肝静脉闭塞病模型.肝静脉闭塞病的机制与全身照射后造成的肝脏内皮损伤、炎症细胞浸润及移植后细胞因子的变化密切相关.     

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.     

胚胎肝细胞移植治疗小鼠肝纤维化

目的 观察移植胚胎肝细胞减轻小鼠肝纤维化的作用.方法 孕14 d的BALB/C小鼠胚胎肝细胞移植到雌性BALB/C小鼠肝脏,二乙基亚硝胺诱导肝纤维化.60只雌性小鼠随机分为对照组,模型组及治疗组.3个月后测定血清谷丙转氨酶(ALT)、谷草转氨酶(AST)、透明质酸酶(HA)、层粘连蛋白(LN)浓度及肝脏羟基脯氨酸(Hyp)含量.免疫组织化学检测肝脏α-平滑肌肌动蛋白(α-SMA)表达及Y染色体性别决定区域蛋白(SRY)表达来确定移植的胚胎肝细胞在肝内的增殖分化.结果 移植胚胎肝细胞能显著降低血清ALT、AST、HA和LN的水平(P＜0.01).胚胎肝细胞移植组肝脏Hyp含量也明显低于模型组(P＜0.01).移植组肝脏α-SMA的表达明显低于模型组.胚胎肝细胞移植及诱导肝纤维化3个月后,胚胎肝细胞能增殖分化为肝细胞和胆管细胞,占肝脏的30%～50%.结论 在诱导肝纤维化过程中,移植胚胎肝细胞有向肝细胞和胆管细胞高增殖分化的能力,并有效地减轻肝损害和肝纤维化.     

基因工程Treg细胞对小鼠异基因骨髓移植后GVHD和GVL效应的影响

目的 探讨输注慢病毒载体介导的小鼠基因工程调节性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)及移植物抗白血病(GVL)效应的影响.方法 利用慢病毒载体介导,将小鼠叉状头螺旋转录因子(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,移植当天受者接受X线直线加速器全身照射.用随机数字表法将受者分为5组,每组10只.(1)单纯照射组:经受者尾静脉输注RPMI 1640培养液0.2 ml;(2)白血病对照组:经受者尾静脉输注供者骨髓细胞5×106个+C57BL/6小鼠T淋巴细胞白血病/淋巴瘤细胞株(EL4细胞)500个;(3)移植对照组:经受者尾静脉输注供者骨髓细胞5×106个+脾细胞5×106个+EL4细胞500个;(4)工程Treg组:经受者尾静脉输注供者骨髓细胞5×106个+脾细胞5×106个+EL4细胞500个+基因工程Treg细胞5×106个;(5)空载体对照组:经受者尾静脉输注供者骨髓细胞5×106个+脾细胞5×106个+EL4细胞500个+空载体转导的CD4+CD25-T淋巴细胞5×106个.每天观察受者存活情况;记录GVHD及白血病的发生情况;各组均于小鼠濒死前取其肝脏、小肠、皮肤、脾脏等组织,进行病理学观察;取长期存活(超过60 d)受者的骨髓细胞,检测嵌合情况.结果 单纯照射组、白血病对照组、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(10.3±1.5)d、(20.7±1.9)d、(26.0±4.3)d、(49.0±17.7)d和(24.4±4.1)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).白血病对照组小鼠肝、脾组织病理切片均存在白血病细胞浸润表现,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存在GVHD病理改变,而工程Treg组长期存活小鼠各组织病理切片结构基本正常,未见GVHD及白血病细胞浸润病理表现,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的发生并保留GVL效应.     

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.     

骨髓间充质干细胞的输注时机对小鼠骨髓移植后急性移植物抗宿主病的影响

目的 探讨骨髓间充质干细胞(MSCs)输注时机对异基因骨髓移植(allo-BMT)后急性移植物抗宿主病(aGVHD)的影响及其机制.方法 以Babl/c小鼠为供者,于无菌条件下获取其骨髓,制成MSCs悬液及骨髓细胞悬液.C57BL/6小鼠为受者,经电子直线加速器行全身照射后,分为5组进行allo-BMT.骨髓移植组受者经尾静脉输注骨髓细胞悬液和RPMI 1640培养液各0.2 ml;联合移植组受者经尾静脉输注骨髓细胞悬液和MSCs悬液各0.2 ml;延迟输注Ⅰ组受者经尾静脉输注骨髓细胞悬液0.2 ml,3 d后再输注MSCs悬液0.2 ml;延迟输注Ⅱ组受者经尾静脉输注骨髓细胞悬液0.2 ml,7 d后再输注MSCs悬液0.2 ml;对照组受者经尾静脉输注RPMI 1640培养液0.4 ml.记录受者存活时间及aGVHD的发生情况,检测外周血白细胞、CD4+ 和CD8+淋巴细胞数,测定血清γ干扰素(IFN-γ)和白细胞介素4(IL-4)水平,观察死亡小鼠的肝、脾、小肠及皮肤等组织病理学变化.结果 对照组受者均于移植后14 d内死亡.骨髓移植组于移植14 d以后出现aGVHD的表现,且均于23 d内死亡.联合移植组aGVHD的发生率为30%,延迟输注Ⅰ组aGVHD的发生率为60%,两组受者的存活时间均长于骨髓移植组.延迟输注Ⅱ组与骨髓移植组间aCVHD发生率和死亡时间的差异无统计学意义.受者的白细胞数均于全身照射后3 d降至最低,各移植组白细胞数皆于移植后回升,但骨髓移植组和延迟输注Ⅱ组的白细胞数未能恢复至正常水平,而联合移植组和延迟输注Ⅰ组的白细胞数均于移植后28 d恢复正常.输入MSCs者,CD4+淋巴细胞数量明显升高,而CD8+淋巴细胞数量下降,以联合移植组最为明显.联合移植组的IFN-γ水平明显低于骨髓移植组,而IL-4水平高于骨髓移植组.各组发生aGVHD的小鼠的肝、脾、小肠及皮肤病理改变基本一致.结论 MSCs与骨髓同时输注时aGVHD的发生率最低,受者的存活时间也最长,其机制可能与细胞因子水平有关.     

小鼠肝动脉重建对长时间冷保存移植肝存活率的影响

目的研究小鼠肝动脉重建(hepatic arterial reconstruction,HAR)对长时间冷保存移植肝存活率的影响。方法同系雄性C57BL/6小鼠68只,分为冷保存时间(cold preservation time,CPT)1 h组、CPT4 h组、CPT8 h组、CPT16 h组、CPT16 h+HAR组(供、受体小鼠各一半)。小鼠供肝经门静脉灌注4℃UW液后保存。肝脏移植采用缝合法(肝上下腔静脉)和袖套法(门静脉、肝下下腔静脉)吻合,胆管采用内支架管重建法。小鼠HAR采用含供体肝动脉的腹主动脉与受体腹主动脉端侧吻合的方法。观察术后5组受体小鼠移植肝的存活时间,用组织学检查肝细胞损伤情况,用免疫组织化学法观察肝细胞再生功能。结果 CPT1 h、4 h、8 h组受体术后12 d移植物的存活率分别为7/7、10/10、9/9。CPT16 h组除1例小鼠存活外,其余均在移植术后36 h内死亡,存活率为10%(1/10),CPT16 h+HAR组受体90%(9/10)存活,两组存活率相比,差异有统计学意义(P0.01)。CPT1 h、4 h组的移植物组织损伤程度轻,CPT8 h组的移植物组织损伤程度较前两组严重,但肝细胞再生活跃。CRT16 h组的移植肝组织表现为广泛肝细胞空泡变性、坏死,肝细胞再生不明显。CPT16 h+HAR组仅有轻度的肝窦淤血,肝细胞空泡变性、坏死改变,肝细胞再生活跃。结论 HAR可提高长时间冷保存移植肝的存活率。     

腹主动脉移植后小鼠外周血内皮祖细胞数量的动态变化及意义

目的 观察腹主动脉移植后小鼠移植物动脉硬化的病变过程及外周血内皮祖细胞(EPC)数量的动态变化,探讨EPC与动脉内膜损伤和修复的相互关系.方法 以C57BL/6小鼠和Balb/c小鼠为供、受者,建立腹主动脉原位移植后移植性模型.术后3 d、2周、4周、6周,观察移植动脉病理改变,并采用计算机图像分析系统分析移植血管内膜增生情况.使用流式细胞仪监测术后外周血中EPC数量的变化.结果 术后3 d,移植动脉内皮细胞损伤,并伴有明显的炎症细胞浸润.术后2周,即可观察到移植动脉新生内膜形成,存在急性排斥反应;术后4周、6周内膜厚度逐渐增生,移植动脉管腔明显狭窄.术后早期外周血中EPC的数量增多,3 d时达到高峰,此后迅速减少,术后14和28 d时,显著低于术前水平(P＜0.05).结论 通过同种小鼠腹主动脉原位移植可成功复制出移植物动脉硬化的病变特点;外周血中EPC的数量与移植动脉内膜损伤的修复密切相关,可能成为移植物动脉硬化的发病指标和干预靶点.     

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.     

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.     

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.     

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.     

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.