保留自身关节保肢术治疗膝关节周围骨肉瘤的术式选择与临床疗效

[目的]分析保留自身关节保肢术治疗膝关节周围骨肉瘤的失败原因,指导临床选择正确的修复肿瘤性骨缺损的方式。[方法]1999年1月²012年12月,对21例膝关节周围骨肉瘤患者行保留自身关节的保肢手术。男12例,女9例;年龄平均14.05岁(52012年12月,对21例膝关节周围骨肉瘤患者行保留自身关节的保肢手术。男12例,女9例;年龄平均14.05岁(5²4岁)。股骨远端19例,胫骨近端2例。MR分型I型15例(2例为合并病理骨折),II型6例。保留骨骺的瘤段切除灭活再植术7例,保留关节的瘤段切除灭活再植术10例,保留骨骺的瘤段切除异体骨移植术2例(1例为带血管蒂腓骨复合异体骨移植术),保留骨骺的骨骺牵张骨搬运术2例。髓内针14例,钢板5例,外固定架2例。[结果]所有患者均获得随访,平均46.47个月(1224岁)。股骨远端19例,胫骨近端2例。MR分型I型15例(2例为合并病理骨折),II型6例。保留骨骺的瘤段切除灭活再植术7例,保留关节的瘤段切除灭活再植术10例,保留骨骺的瘤段切除异体骨移植术2例(1例为带血管蒂腓骨复合异体骨移植术),保留骨骺的骨骺牵张骨搬运术2例。髓内针14例,钢板5例,外固定架2例。[结果]所有患者均获得随访,平均46.47个月(12¹50个月),2例分别于术后12个月和8年复发,死亡7例(12150个月),2例分别于术后12个月和8年复发,死亡7例(12¹08个月),14例存活(12108个月),14例存活(12¹50个月)。骨干连接部位的愈合时间平均为14.4个月(6150个月)。骨干连接部位的愈合时间平均为14.4个月(6³6个月),骨骺连接部位的愈合时间平均6.95个月(336个月),骨骺连接部位的愈合时间平均6.95个月(3³6个月)。螺钉松动1例;骨折8例(1例异体骨吸收),7例行10例次切开复位植骨内固定术,1例次行肢体延长术;另1例患者未治疗。除1例骨折和1例复发未处理之外,12例患者的肢体MSTS评分为1536个月)。螺钉松动1例;骨折8例(1例异体骨吸收),7例行10例次切开复位植骨内固定术,1例次行肢体延长术;另1例患者未治疗。除1例骨折和1例复发未处理之外,12例患者的肢体MSTS评分为15³0分,平均为26.7(88.9%)。[结论]年龄、病变性质、部位、骨破坏程度和内固定方式是导致手术失败的主要因素。在严格遵循手术适应证的前提下,应该根据上述因素选择不同的骨修复重建方式。     

骨骺牵开保留儿童骨肉瘤骨骺的临床研究

目的探讨采用外固定架行骨骺牵开术保留儿童股骨骨肉瘤远端骨骺及关节功能的可行性。方法 2007年7月-2011年5月,对6例股骨下段成骨性骨肉瘤患儿行外固定架牵引分离股骨远端骨骺,配合瘤骨切除、大段同种异体骨重建术治疗。男4例,女2例;年龄9～14岁,平均10.5岁。骨肉瘤按照Enneking外科分期:ⅡA期4例,ⅡB期2例。干骺端骨肿瘤侵袭情况按照San-Julian等的影像学分型标准分型:Ⅰ型3例,Ⅱ型3例。肿瘤范围6 cm×4 cm～12 cm×9 cm。术前行2个周期、术后行4个周期COSS 86化疗。结果术后1例因同种异体骨排斥反应导致切口愈合不良,经对症治疗后愈合;其余患儿切口均Ⅰ期愈合。6例均获随访,随访时间11～56个月,平均37.5个月。1例因肺部转移于术后2年死亡。X线片示,随访期间未发生内固定物松动、断裂及骨不愈合等并发症。末次随访时,按照国际保肢协会(ISOLS)评估标准评估,获优3例、良2例、可1例,优良率83.3%。患侧肢体长度为(62.97±7.51)cm,与健侧(64.03±7.47)cm相似,比较差异无统计学意义(t=0.246 6,P=0.813 4)。结论在严格把握适应证、规范化疗和彻底切除瘤骨前提下,骨骺牵开术可较好地保留股骨成骨性骨肉瘤患儿的患肢生长机能及关节功能。     

关节囊外整块切除保留胫骨骨骺可延长肿瘤型假体治疗儿童股骨远端骨肉瘤

[目的]对儿童股骨远端骨肉瘤(San-Julian分型III型)行关节囊外整块切除联合使用保留胫骨骨骺可延长肿瘤型人工关节假体重建术的早期临床研究。[方法] 2017年10月～2018年10月,共6例患儿在本院行穿刺活检病理学证实为骨肉瘤,影像学分型,均为San-Julian分型III型,其中男2例,女4例;年龄7～12岁;左侧3例,右侧3例。均在本科接受关节囊外整块切除联合保留胫骨骨骺可延长肿瘤型人工假体重建术,术后指导患儿进行功能锻炼,伤口2周后拆线,再过1周后即给予术后的规范化化疗,并进行随访。[结果] 6例患儿手术时间分别为2.5 h、3 h、3 h、3.2 h、3.5 h和4 h,平均(3.20±1.14) h;术中出血量600～1 200 ml,平均(850.00±484.77) ml。6例患儿均获随访9～21个月,平均(15.17±9.53)个月。根据美国骨肿瘤学会评分系统(Musculoskeletal Tumor Society, MSTS),术后3个月功能评分18～27分,平均(22.83±7.67)分,患儿肢体功能达到良好标准。末次随访,患肢膝关节屈曲角度90°～110°共4例,110°～130°共2例,伸直均能达到180°;共5例患儿双下肢长度相差1.5 cm,1例患儿双下肢长度差异约为2.5 cm。随访期间所有患儿均未出现局部复发及肺部转移。[结论]通过严格把握手术适应证,对于股骨远端骨肉瘤San-Julian分型中的III型的患儿,关节囊外切除联合使用保留胫骨骨骺可延长肿瘤型人工关节假体重建术提供了一种安全有效的手术方式。     

经皮闭合复位弹性髓内钉固定治疗儿童股骨转子下骨折

[目的]探讨评价闭合复位弹性髓内钉固定技术治疗儿童股骨转子下骨折的效果。[方法]2008年12月~2014年10月,采用闭合复位弹性髓内钉固定技术治疗21例股骨转子下骨折患儿。男15例,女6例;年龄4~12岁,平均7.7岁。左侧12例,右侧9例,致伤因素:交通事故伤13例,高处坠落伤7例,溜冰摔伤1例。均为新鲜闭合骨折。依据Seinsheimer分型:ⅡA型2例,ⅡB型7例,ⅡC型7例,ⅢB型3例,Ⅳ型2例。受伤至手术时间2~9 d,平均5.4 d。术后参照Flynn髓内钉治疗股骨骨折的评分标准评价术后患肢功能。[结果]手术时间25~60 min,平均32 min。术后患者切口均Ⅰ期愈合,无感染、无神经血管损伤等并发症发生。21例均获随访,随访时间18~56个月,平均24个月。术后3个月时骨折均达骨性愈合。随访期间无髓内钉折断、再骨折、骨骺早闭、股骨头缺血性坏死、下肢过度生长等并发症发生。1例SeinsheimerⅣ型患儿术后3个月骨折愈合后患肢较健侧短缩1.5 cm,随访30个月后双下肢等长。末次随访时,患肢功能按Flynn评定标准,获优19例,良2例,优良率100%。末次随访测量X线片有5例(23.8%,5/21)断端向前成角2°~8°,平均3.8°;3例(14.3%,3/21)向后成角2°~6°,平均4.0°;无内外翻成角。[结论]只要规范掌握复位及固定技巧,弹性髓内钉技术能够实现儿童股骨转子下骨折闭合复位及有效的固定,取得满意的手术效果,安全、微创,是一种理想的治疗方法。     

锚钉缝线桥技术避骨骺内固定治疗青少年PCL胫骨止点撕脱骨折

目的探讨应用锚钉缝线桥技术避骨骺内固定治疗青少年后交叉韧带(posterior cruciate ligament,PCL)胫骨止点撕脱骨折的临床疗效。方法我院自2014年4月至2017年7月共收治6例后交叉韧带胫骨止点撕脱骨折的青少年患者,其中男4例,女2例;年龄8~17岁,平均(13.0±3.0)岁。均为McKeeverⅢ型骨折,采用膝后内侧入路双排锚钉缝线桥技术避开骨骺固定骨折块,并记录手术时间、术后并发症、骨折愈合情况、末次随访膝关节屈伸活动度及肢体长度,应用Lysholm膝关节评分系统评估膝关节功能,并与健侧进行对比分析。结果6例患者均获随访,随访时间在24~36个月,平均(29.7±4.1)个月。手术时间53~68 min,平均(59.8±5.2)min。手术切口均甲级愈合,无神经血管损伤,所有骨折均愈合良好,愈合时间8~12周,平均(9.33±1.49)周。末次随访时患膝Lysholm评分为94~97分,平均(95.0±1.3)分;关节活动度伸膝-5°~2°,平均(-1.3±2.3)°;屈膝130°~143°,平均(135.5±4.8)°,肢体长度62.8~95.0 cm,平均(82.3±10.9)cm;术后各指标与健侧相比差异均无统计学意义(P>0.05)。结论应用双排锚钉缝线桥技术避开骨骺固定青少年膝后交叉韧带胫骨止点撕脱骨折,可以避免骨骺损伤,固定牢靠,功能恢复好,取得良好的临床疗效。     

MIPPO结合DHS治疗老年股骨粗隆间骨折

[目的]利用MIPPO(minimally invasive percutaneous plate osteosynthesis)微侵入经皮钢板植入技术植入DHS(动力髋螺钉)治疗老年股骨粗隆间骨折,以减少手术所造成的创伤反应。[方法]回顾性分析本院2004年7月~2005年10月收治的75例老年股骨粗隆间骨折,内固定材料均选用DHS,其中29例采用MIPPO置入,46例采用常规切口置入,比较两种手术方式的创伤程度。主要考察指标:手术切口长度、术中出血量、术中及术后输血量、术后血红蛋白(HB)下降幅度、术后术区肢体肿胀情况、血沉(ESR)等来反映手术中创伤大小。[结果]M IPPO组手术切口平均长度为5.2 cm,常规组为11.3 cm。MIPPO组失血少,术中及术后无需输血,术后血红蛋白下降幅度小,术后患肢肿胀轻,消肿快,ESR恢复快,卧床时间短。围手术期死亡2例(均为常规切口组),其余患者均顺利出院,获7~21个月随访,平均12.3个月。1例在随访期间死于其他内科疾病,其余所有骨折均愈合,平均愈合时间为3.5个月(常规切口组)和3、4个月(M IPPO组),两组骨折愈合时间无显著性差异。[结论]采用小切口技术植入DHS内固定治疗老年股骨粗隆间骨折手术创伤小,有利于患者全身状况和肢体功能的恢复。     

儿童股骨远端骨肉瘤保留骨骺的定制肿瘤型假体重建术

 目的 介绍儿童股骨远端骨肉瘤保留骨骺的定制肿瘤型假体重建术,并探讨其工作原理、手术操作技巧、早期临床疗效以及并发症的防治。方法 2012年8月至2013年7月期间,应用肿瘤瘤段骨切除、保留骨骺的定制肿瘤型假体重建术治疗股骨远端骨肉瘤的儿童患者3例,均为男性,年龄8岁、9岁和15岁。术前给予新辅助化疗1~2周期,化疗结束后根据X线、CT 和MR等检查结果评价化疗疗效,对于化疗效果好且符合保留骨骺手术条件者采用此术式治疗。首先通过CT、MRI确定病变范围,根据影像学检查结果利用计算机辅助定制保留骨骺的肿瘤型假体以及模具,待假体定制完毕后行肿瘤瘤段骨切除、保留骨骺的定制肿瘤型假体重建术,术后指导患者进行功能锻炼,切口愈合1周后给予术后的规范化化疗,并进行长期随访。 结果 3例患者手术时间分别为3 h、4 h和6 h,术中出血量分别为300 ml、500 ml和2 200 ml。对3例患者术后随访时间 为12~24个月,根据美国骨肿瘤学会评分系统（Musculoskeletal Tumor Society,MSTS）,术后3个月功能评分分别为24分、26分和13分,短期随访显示患者肢体功能良好。1例患者出现假体感染,经保守治疗（抗炎补液、切口换药等）无效后行大腿截肢术,余2例患者未出现假体松动等其他并发症。2例患者双下肢长度相差均< 2 cm。结论 通过严格掌握保留骨骺保肢手术的适应证,配合术前及术后的新辅助化疗,保留骨骺的定制肿瘤型假体重建术为儿童股骨远端骨肉瘤的保肢治疗提供了新的选择方案,其疗效安全、可靠,且具有手术操作简单、手术时间短、术后恢复快等优点,但长期疗效尚需进一步观察。     

可吸收钉固定治疗儿童胫骨远端骨骺损伤15例

[目的]探讨切开复位可吸收钉固定治疗儿童胫骨远端骨骺损伤的疗效。[方法]回顾分析本院2006年1月~2011年12月采取切开复位可吸收螺钉固定方法治疗的胫骨远端骨骺损伤患儿37例,其中15例获得随访;手术年龄5~15岁,平均12岁,其中男11例,女4例;左侧11例,右侧4例。按Salter-Harris骨骺损伤分型:Ⅱ型7例,Ⅲ型4例(包括1例Tillaux骨折),Ⅳ型2例,三平面骨折2例。所有患儿随访14~75个月,平均36.1个月。手术在C型臂X线机透视下进行,切开复位达到解剖复位后可吸收螺钉固定。术后石膏托固定6~8周。以改良Weber评估标准评价踝关节功能及愈合情况;拍摄双下肢全长正位、双踝关节正侧位X线片,评估切开复位可吸收钉治疗儿童胫骨远端骨骺损伤的疗效。[结果]本研究所有患侧与健侧下肢影像学分析结果显示:下肢机械轴与水平线成角,胫骨长度健侧与患侧比较差异有统计学意义(P<0.05)。而正侧位踝穴角患侧与健侧比较差异无统计学意义(P>0.05)。对获得随访的15例按改良Weber评分,优13例,良2例。所有患儿踝关节活动均不受限,均能参加正常的体育活动。X线片检查所有病例均骨性愈合,其中2例发生骨骺早闭,有骨桥形成,踝关节内翻畸形,肢体短缩并伴有下肢机械轴线的偏移。[结论]可吸收钉对胫骨远端骨骺损伤的固定可靠,对骨折愈合和踝关节功能恢复而言,具有良好的效果。     

Hoffa骨折并内侧副韧带撕脱手术与快速康复

[目的]介绍Hoffa骨折并内侧副韧带撕脱骨折的手术技术与快速康复方法和初步临床效果。[方法] 2016年5月—2021年3月收治内侧Hoffa骨折伴内侧副韧带起点撕脱骨折患者3例，均采用经内侧切口骨折切开复位钢板螺钉及全螺纹空心钉坚强固定，内侧副韧带止点空心拉力螺钉固定，辅助爱惜邦缝线加强固定，术后将膝关节屈曲110°～120°放置，镇痛泵止痛，行踝关节功能锻炼以及股四头肌等长收缩训练。24 h后行膝关节伸屈功能锻炼，3次/d，每次30 min，锻炼后膝关节继续屈曲110°～120°固定共3 d,3 d后根据膝关节伸屈功能情况决定膝关节放置体位。[结果] 3例患者均顺利完成手术，术中无血管、神经损伤等严重并发症。患者切口均一期愈合。术后2个月膝关节屈曲ROM为（142.3±8.7）°，末次随访，膝关节HSS评分为（85.4±5.1）分，膝关节功能恢复良好，无膝关节僵硬发生。骨折愈合时间3～6个月，至末次随访时，所有骨折愈合良好，未出现内固定松动移位、修复的韧带再断裂等不良影像改变。[结论] Hoffa骨折并内侧副韧带起点撕脱骨折，行切开复位坚强固定后，膝关节屈曲110°～120°固定...     

120°儿童髋锁定加压钢板治疗儿童股骨转子下骨折

[目的]探讨120°儿童髋锁定加压钢板(120°Locking compression paediatric hip plate,120°LCP PHP)治疗儿童股骨转子下骨折的临床疗效。[方法]2010年10月~2014年5月采用120°LCP PHP治疗儿童股骨转子下骨折16例。[结果]本组患儿术后随访24~36个月,平均(27.3±3.2)个月。无1例发生神经血管损伤、骨折端再移位、再骨折、髋内翻、骨髓炎、股骨头坏死及骨骺发育异常。骨折骨性愈合时间为8~13周,平均(10.1±1.4)周,无骨不愈合。于术后18~32周取出内固定物,平均(25.3±3.4)周。早期Beaty评分及远期Theologis评分皆为满意,术后2年Sanders髋关节评分为57~60分,平均(58.7±2.1)分,都为优,优良率为100%。[结论]120°LCP PHP治疗儿童股骨转子下骨折,具有符合儿童股骨转子下解剖及生物力学特点、固定牢固、避免损伤骨骺、骨折愈合快、并发症少、适应证广、可早期功能锻炼等优点。但存在需要切开复位、损伤相对较大、出血较多、二次手术切开取出内固定物、费用较高、切口瘢痕影响美观等缺点。     

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 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.     

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.