Ⅰ型神经纤维瘤病软骨细胞生物学特性的研究

目的检测神经纤维瘤蛋白在Ⅰ型神经纤维瘤病（type 1 neurofibromatosis，NF1）脊柱侧凸患者软骨细胞中的表达，观察NF1脊柱侧凸患者软骨细胞的生物学特性。方法先天性脊柱侧凸患者7例，NF1脊柱侧凸患者6例，两组年龄和Cobb角接近。脊柱后路手术中取髂骨生长板行软骨细胞分离和培养。取第2代软骨细胞分别检测其增殖活性和Ⅱ型胶原、可聚蛋白多糖等软骨细胞特异性分化指标，并用免疫沉淀和Western blot检测神经纤维瘤蛋白在两组软骨细胞中的表达。结果NF1脊柱侧凸患者软骨细胞中神经纤维瘤蛋白表达水平明显低于先天性脊柱侧凸组（灰度积分比值分别为1．31±0．53和2．17±1．02，P=0．03），其Ⅱ型胶原水平明显低于先天性脊柱侧凸患者组（26．6±11．3ng／mgpro和31．7±16．2ng／mgpro，P=0．03），而可聚蛋白多糖水平两组无明显差异（63．0±129．6ng／mgpro和76．7±519．4ng／mgpro，P=0．21）。NF1脊柱侧凸患者软骨细胞显示相对活跃的增殖活性（增殖倍数分别为2．9±0．04和2．49±0．11，P=0．02）。结论NF1脊柱侧凸患者软骨细胞神经纤维瘤蛋白表达降低的同时，其细胞增值相对活跃，细胞分化功能也存在缺陷。     

Ⅰ型神经纤维瘤病成骨细胞生物学特性的研究

目的检测神经纤维瘤蛋白在Ⅰ型神经纤维瘤病(type1neurofibromatosis,NF1)脊柱侧凸患者成骨细胞中的表达,观察NF1脊柱侧凸患者成骨细胞的生物学特性。方法先天性脊柱侧凸患者10例,NF1脊柱侧凸患者8例,两组年龄和Cobb角相近。脊柱后路手术取髂骨松质骨,采用植块法进行成骨细胞培养。取第二代成骨细胞分别检测其增殖活性、碱性磷酸酶、Ⅰ型胶原和骨钙素等成骨细胞特异性分化指标,并采用免疫沉淀和Westernblot法检测神经纤维瘤蛋白在两组成骨细胞中的表达。结果NF1脊柱侧凸患者成骨细胞中神经纤维瘤蛋白表达水平明显低于先天性脊柱侧凸患者(灰度积分比值分别为1.05±0.06和2.59±1.40,P=0.002);碱性磷酸酶、Ⅰ型胶原和骨钙素水平均明显低于先天性脊柱侧凸患者(44.69IU/mg和51.38IU/mg,P=0.019;226.34ng/mg和249.93ng/mg,P=0.014;7.41ng/mg和8.87ng/mg,P=0.049)。NF1脊柱侧凸患者成骨细胞显示相对活跃的增殖活性(增殖倍数分别为3.34和2.70,P=0.049)。结论NF1脊柱侧凸患者成骨细胞神经纤维瘤蛋白表达降低的同时,其功能存在明显缺陷。成骨细胞功能缺陷可能是骨骼营养不良性改变和骨密度降低等各种骨骼异常共同的基础。     

青少年Ⅰ型神经纤维瘤病性脊柱侧凸患者的骨密度

目的:观察青少年Ⅰ型神经纤维瘤病(neurofibromatosis 1,NF1)性脊柱侧凸患者的骨密度(BMD)情况,探讨BMD与其脊柱侧凸类型和严重程度的关系。方法:2008年3月～2010年4月收治青少年NF1伴胸椎脊柱侧凸患者23例,按照脊椎有无特征性异常改变分为营养不良性脊柱侧凸组(A组)和非营养不良性脊柱侧凸组(B组),其中A组患者14例,男9例,女5例,年龄10～18岁,平均13.4岁,侧凸Cobb角60°～132°,平均84.1°;B组9例,男5例,女4例,年龄11～16岁,平均13.2岁,侧凸Cobb角40°～87°,平均71.4°。以同年龄非脊柱畸形志愿者24例为对照组(C组),男16例,女8例,年龄10～17岁,平均14.7岁。所有研究对象均采用双能X线吸收仪测量非优势侧的股骨近端(大转子、股骨颈和Ward′s三角)和腰椎(L2～L4)的BMD,将3组受试者的测量结果进行单因素方差分析(one-way ANOVA),并在A组和B组内对BMD与Cobb角进行Pearson相关分析。结果:3组受试者年龄、性别构成比无统计学差异(P>0.05)。A组与B组Cobb角无统计学差异(P>0.05),A组腰椎及非优势侧股骨近端的BMD与B组相应部位比较均无统计学差异(P>0.05);A、B两组患者上述各部位的BMD均明显低于C组相应部位(P<0.05),腰椎BMD降低比股骨近端明显。A、B组各部位BMD与Cobb角无显著相关性(P<0.05)。结论:青少年NF1伴营养不良性脊柱侧凸与非营养不良性脊柱侧凸患者均存在骨量下降,但BMD与脊椎是否为营养不良性改变以及侧凸严重程度无关。     

青少年特发性脊柱侧凸患者椎旁肌中钙调蛋白的表达及临床意义

目的:探讨青少年特发性脊柱侧凸(AIS)患者椎旁肌钙调蛋白的表达及其对肌浆网钙离子通道的影响。方法:AIS患者共30例,Cobb角40°～100°,其中Cobb角≥50°者15例(A组),Cobb角<50°者15例(B组);对照组(C组)5例患者均为非脊柱侧凸病例。于手术中取A、B组患者顶椎区两侧椎旁肌、取C组患者非病变部位两侧椎旁肌作为标本进行分子生物学分析,采用RT-PCR方法检测所有标本钙调蛋白和肌浆网钙离子通道的mRNA表达量。结果:A、B组患者椎旁肌钙调蛋白mRNA的表达比C组高(P<0.05),并且A组患者凸侧椎旁肌钙调蛋白mRNA显著高于凹侧(P<0.05),而B组患者其凹凸侧钙调蛋白mRNA没有显著性差异(P>0.05);C组椎旁肌肌浆网钙离子通道mRNA的表达比A组患者高(P<0.05),A组患者凸侧椎旁肌肌浆网钙离子通道mRNA显著低于凹侧(P<0.05),而B组患者其凹凸侧肌浆网钙离子通道mRNA没有显著性差异。结论:钙调蛋白mRNA在AIS患者椎旁肌中的表达较无脊柱侧凸者高,而且其表达随着侧凸程度的加重而增高;AIS患者椎旁肌肌浆网钙离子通道表达有异常,钙调蛋白的过度表达可能导致了钙离子通道的损伤。     

神经纤维瘤蛋白在先天性脊柱侧凸患者成骨细胞和软骨细胞中的表达

目的：检测神经纤维瘤蛋白在先天性脊柱侧凸患者成骨细胞和软骨细胞中的表达。方法：6例先天性脊柱侧凸患者，在后路手术时取髂骨及髂骨生长板，分离、培养成骨细胞和软骨细胞，分别行碱性磷酸酶染色和甲苯胺蓝染色。逆转录-多聚酶链反应（RT—PCR）检测神经纤维瘤蛋白mRNA．间接免疫荧光和Westemblot检测神经纤维瘤蛋白在成骨细胞和软骨细胞中的表达。结果：先天性脊柱侧凸患者成骨细胞和软骨细胞中存在Ⅱ型神经纤维瘤蛋白表达，该蛋白主要分布在细胞浆，所表达蛋白为三磷酸鸟苷酶活化蛋白（GAP）活性较弱的Ⅱ型异构体。结论：先天性脊柱侧凸患者成骨细胞和软骨细胞中存在神经纤维瘤蛋白表达，但该蛋白是否通过对成骨细胞和软骨细胞的影响导致骨骼系统异常还有待于进一步研究。     

青少年特发性脊柱侧凸患者椎体生长板中Runx2及Ⅹ型胶原表达

目的:观察青少年特发性脊柱侧凸(AIS)患者上、下端椎和顶椎椎体生长板凸、凹侧软骨细胞的生物活性差异;探讨其在AIS发生和发展中的作用.方法:在对12例AIS患者行胸椎侧凸前路松解手术或前路矫形手术时获取上、下终椎和顶椎椎体生长板;分成凸、凹侧2组;共72枚标本;应用免疫组织化学方法检测Runx2和Ⅹ型胶原蛋白的表达;原位杂交方法检测Runx2 mRNA表达.所有染色结果通过图像分析系统进行半定量分析.结果:AIS患者顶椎椎体生长板凸、凹两侧的Ⅹ型胶原、Runx2和Runx2 mRNA表达总量存在显著性差异(P＜0.05).顶椎椎体生长板凹侧Ⅹ型胶原的表达总量低于下终椎椎体生长板凹侧的表达总量(P＜0.05).顶椎椎体生长板凹侧Runx2的表达总量低于上、下终椎椎体生长板凹侧的表达总量(P＜0.05).顶椎椎体生长板凹侧单一软骨细胞Runx2表达量高于凸侧和上、下终椎椎体生长板凹侧单一软骨细胞的表达(P＜0.05).顶椎椎体生长板凹侧高倍视野下平均Runx2 mRNA表达总量低于上、下终椎椎体生长板的凹侧(P＜0.05).顶椎椎体生长板凸侧单一细胞Runx2 mRNA表达量低于凹侧(P＜0.05).顶椎椎体生长板凹侧高倍视野下平均Ⅹ型胶原阳性细胞密度和Runx2阳性细胞密度低于凸侧和上、下终椎椎体生长板凹侧阳性细胞密度(P＜0.05).结论:AIS患者上、下终椎和顶椎椎体生长板凸、凹侧软骨细胞存在不同的生物活性和细胞动力学;这可能是力学条件改变后的一种继发性改变;但其可能在AIS的进展中发挥重要作用.     

血管内皮生长因子对关节软骨细胞诱导型一氧化氮合酶的影响

目的 观察血管内皮生长因子(VEGF)对体外培养的关节软骨细胞诱导型一氧化氮合酶(iNOS)表达的影响。方法 体外培养SD乳鼠关节软骨细胞,用白细胞介素(IL)-1β诱导的方法建立骨关节炎(OA)体外模型,实验分为4组,每组加入不同处理因素进行干预,A组:(正常对照组)不加任何处理因素;B组:10 μg/L VEGF;C组:10 μg/L IL-1β;D组:10 μg/L VEGF+ 10 μg/LIL-1β。采用实时荧光定量PCR( Real Time PCR)检测iNOS mRNA的表达,采用蛋白免疫印迹法( Western blot)检测iNOS蛋白的表达。结果 iNOS mRNA的表达:A组iNOS mRNA无表达,B组(9.64±1.64)、C组(17.27±2.01)及D组(28.93±6.63),3组的iNOS mRNA表达量显著升高,进一步组间比较,D组软骨细胞iNOS的mRNA表达水平明显高于B组(P＜0.01)及C组(P＜0.05),C组软骨细胞iNOS的mRNA表达水平高于B组(P＜0.05)。iNOS蛋白的表达:A组iNOS蛋白无表达,B组(0.44±0.12)、C组(0.74±0.07)及D组(1.38±0.38),3组的iNOS蛋白表达量显著升高,进一步组间比较,D组软骨细胞iNOS的蛋白表达水平明显高于B组(P＜0.01)及C组(P＜0.05),C组软骨细胞iNOS的mRNA表达水平高于B组(P＜0.01)。结论 在OA的发病过程中,VEGF可能通过上调软骨细胞iNOS的表达发挥重要作用。     

营养不良型和非营养不良型神经纤维瘤病性脊柱侧凸中异常椎弓根发生率的比较

目的:观察Ⅰ型神经纤维瘤病性脊柱侧凸(neurofibromatosis type 1 scoliosis,NF1-S)中椎弓根异常的发生率,并比较其在营养不良型和非营养不良型NF1-S患者中的差异。方法:基于CT图像测量30例营养不良型和30例非营养不良型NF1-S患者的椎弓根,并根据椎弓根最宽平面的最窄距离将这些椎弓根分为5种类型:A型,松质骨通道4mm;B型,松质骨通道2~4mm;C型,松质骨通道2mm且皮质骨通道≥2mm;D型,皮质骨通道2mm且椎弓根存在;E型,椎弓根缺如。B、C、D和E型定义为异常。比较异常椎弓根在不同分型NF1-S患者中的发生率情况及其在侧凸弧范围内的分布情况。结果:NF1-S患者中异常椎弓根的发生率为67.5%(1376/2040),其中B型39.6%(807/2040),C型22.3%(455/2040),D型3.6%(74/2040),E型2.0%(40/2040)。侧凸弧范围内异常椎弓根发生率高达75.3%(975/1294),占全部异常椎弓根的70.9%(975/1376)。对于侧凸弧范围内,营养不良型NF1-S异常椎弓根发生率显著高于非营养不良型(83.3%vs.66.7%,P0.05)。结论:NF1-S患者异常椎弓根主要集中于侧凸弧范围内,且营养不良型异常椎弓根发生率显著高于非营养不良型。     

特发性脊柱侧凸患者椎旁肌中胶原的表达及意义

目的:通过比较特发性脊柱侧凸(idiopathic scoliosis,IS)、先天性脊柱侧凸(congenital scoliosis,CS)顶椎凹凸侧椎旁肌和无脊柱侧凸患者椎旁肌的组织形态学改变及胶原蛋白表达的变化,探讨椎旁肌在IS发展中的作用机制。方法:分别取IS患者(A组)、CS患者(B组)顶椎凹凸两侧及无脊柱侧凸患者(对照组,C组)的椎旁肌,光镜和电镜下观察其组织学形态学改变;应用Masson三色染色法显示胶原蛋白的表达,图像分析系统测量各组胶原的阳性表达面积百分比;对各组结果采用SPSS13.0软件进行统计学处理。应用免疫组织化学方法对Ⅰ型和Ⅲ型胶原染色,观察其在各组的表达情况。结果:光镜和电镜下均显示A、B组凹侧椎旁肌形态明显异常,胶原表达增强、分布紊乱;A、B组凸侧椎旁肌及C组未见明显异常。A、B组凹侧椎旁肌中阳性胶原面积的百分比分别为0.255±0.036和0.253±0.023,明显高于凸侧(A、B组分别为0.057±0.006和0.055±0.002)及C组(0.056±0.004),差异有显著性(P<0.05)。免疫组织化学染色示A、B两组凹侧椎旁肌中Ⅰ型、Ⅲ型胶原表达无明显差异,而在凸侧椎旁肌中以Ⅰ型胶原阳性者为主。结论:IS患者凹侧椎旁肌形态明显异常,胶原表达增强且分布紊乱,其变化可能为IS的继发性改变。     

青少年特发性脊柱侧凸患者椎体生长板中Runx2及X型胶原表达

目的：观察青少年特发性脊柱侧凸（AIS）患者上、下端椎和顶椎椎体生长板凸、凹侧软骨细胞的生物活性差异．探讨其在AIS发生和发展中的作用。方法：在对12例AIS患者行胸椎侧凸前路松解手术或前路矫形手术时获取上、下终椎和顶椎椎体生长板，分成凸、凹侧2组，共72枚标本，应用免疫组织化学方法检测Runx2和X型胶原蛋白的表达．原位杂交方法检测Runx2mRNA表达。所有染色结果通过图像分析系统进行半定量分析。结果：AIS患者顶椎椎体生长板凸、凹两侧的X型胶原、Runx2和Runx2 mRNA表达总量存在显著性差异（P〈0．05）。顶椎椎体生长板凹侧X型胶原的表达总量低于下终椎椎体生长板凹侧的表达总量（P〈0．05）。顶椎椎体生长板凹侧Runx2的表达总量低于上、下终椎椎体生长板凹侧的表达总量（P〈0．05）。顶椎椎体生长板凹侧单一软骨细胞Runx2表达量高于凸侧和上、下终椎椎体生长板凹侧单一软骨细胞的表达（P〈0.05）。顶椎椎体生长板凹侧高倍视野下平均Runx2mRNA表达总量低于上、下终椎椎体生长板的凹侧（P〈0．05）。顶椎椎体生长板凸侧单一细胞Runx2 mRNA表达量低于凹侧（P〈0.05）。顶椎椎体生长板凹侧高倍视野下平均X型胶原阳性细胞密度和Runx2阳性细胞密度低于凸侧和上、下终椎椎体生长板凹侧阳性细胞密度（P〈0．05）。结论：AIS患者上、下终椎和顶椎椎体生长板凸、凹侧软骨细胞存在不同的生物活性和细胞动力学，这可能是力学条件改变后的一种继发性改变，但其可能在AIS的进展中发挥重要作用。     

Reduction of Plasma Fibrinogen, Immunoglobulin G, and Immunoglobulin M Concentrations by Immunoadsorption Therapy with Tryptophan and Phenylalanine Adsorbents

Abstract Immunoadsorption (1A) therapy with tryptophan (TR-350) or phenylalanine (PH-350) adsorbents has been used to reduce the concentration of serum antibodies in human lymphocyte antigen (HLA)-immunized patients. Other forms of plasma purification have been reported to reduce the level of fibrinogen, which affects the blood properties. In this study we investigated the effects of IA therapy using both adsorbents on plasma fibrinogen and immunoglobulins G and M in 13 patients (8 patients were treated with TR-350, and 5 patients were treated with PH-350). During each session 1 plasma volume (2.8 ± 0.4 L of plasma) was processed through the immunocolumn and then returned to the patient together with the blood cells. Compared with the pretreatment values, the plasma fibrinogen, IgG, and IgM concentrations were significantly reduced after IA therapy (p < 0.01 for TR-350; p < 0.04 for PH-350). There was a positive correlation between the degree of reduction of plasma proteins and the number of IA treatments given. A nonpara-metric test (Wilcoxon's signed-rank test or the Mann-Whitney test) was used for statistical analysis. We conclude from our study that IA therapy effectively lowers the plasma levels of fibrinogen, IgG, and IgM and thus can be considered a valuable alternative to other blood purification methods.     

The multiply injured child

Blunt trauma is the principal cause of childhood death in many developed countries. This review outlines the differences between adults and children with respect to resuscitation and treatment of orthopaedic injuries in a child with polytrauma. Recent advances in techniques of fracture stabilization are reported.     

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.     

Development of Selective Low-Density Lipoprotein (LDL) Apheresis System: Immobilized Polyanion as LDL-Specific Adsorption for LDL Apheresis System

Abstract: Low-density lipoprotein (LDL) is widely recognized as one of the major risk factors for developing coronary heart diseases. Despite intensive development of LDL-lowering drugs, there still exist those patients with refractory hyperlipidemia whose plasma LDL levels are not sufficiently lowered by drugs. LDL apheresis, direct removal of plasma LDL from circulating blood, is thought to be the most promising treatment for such refractory patients. Various techniques, such as the use of an im-munoadsorbent utilizing an anti-LDL antibody, have been used in an attempt to achieve the selective removal of LDL. However, none were widely used because of complications, poor selectivity, and so forth. To establish a safe and effective LDL apheresis system, we chose a synthetic affinity adsorbent as the LDL-removing device. Synthetic polyanion compounds were used as the affinity ligands for LDL adsorbent to simulate the anion-rich sequence of LDL binding sites in the human LDL receptor. Among various polyanion compounds, those polyanions with sulfate or sulfonate groups and hydrophilic backbone were found to have strong affinity for LDL. In contrast, polyanions with carboxyl groups showed poor affinity. Dextran sulfate (DS) was selected as the affinity ligand of LDL adsorbent for its high affinity and low toxicity. The influence of its charge density and molecular weight on its affinity for LDL was suitable. The affinity rapidly increased as the charge density increased, then, reached a constant value. Little affinity was found for either the DS monomer (glucose sulfate) or DS with a molecular weight higher than 10⁴ daltons whereas DS with molecular weights in the midrange showed strong affinity. DS with a midrange molecular weight was immobilized on cellulose hard gel to give LDL adsorbent clinical application. The adsorbent demonstrated an excellent selectivity for LDL and very low density lipoprotein (VLDL) in vitro. Adsorption of high-density lipoprotein and major plasma proteins was almost negligible. Additional study of the LDL-binding mechanism revealed that DS directly interacts with positively charged sites on LDL, which demonstrates that the nature of the interaction is the same as that of LDL receptor. An LDL adsorption column (Liposorber) packed with an LDL adsorbent and polysulfone hollow-fiber plasma separator (Sulflux) was developed as an efficient LDL apheresis system. Clinical investigation proved that this system is capable of intensively lowering the plasma LDL level without affecting major plasma components.     

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.     

Artificial organs 2010: a year in review

In this Editor's Review, articles published in 2010 are organized by category and briefly summarized. As the official journal of The International Federation for Artificial Organs, The International Faculty for Artificial Organs, and the International Society for Rotary Blood Pumps, Artificial Organs continues in the original mission of its founders "to foster communications in the field of artificial organs on an international level."Artificial Organs continues to publish developments and clinical applications of artificial organ technologies in this broad and expanding field of organ Replacement, Recovery, and Regeneration from all over the world. We take this time also to express our gratitude to our authors for offering their work to this journal. We offer our very special thanks to our reviewers who give so generously of time and expertise to review, critique, and especially provide such meaningful suggestions to the author's work whether eventually accepted or rejected and especially to those whose native tongue is not English. Without these excellent and dedicated reviewers the quality expected from such a journal could not be possible. We also express our special thanks to our Publisher, Wiley-Blackwell, for their expert attention and support in the production and marketing of Artificial Organs. In this Editor's Review, that historically has been widely received by our readership, we aim to provide a brief reflection of the currently available worldwide knowledge that is intended to advance and better human life while providing insight for continued application of technologies and methods of organ Replacement, Recovery, and Regeneration. We look forward to recording further advances in the coming years.     

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.     

Avaliação do clube de revista de anestesiologia por meio de mudanças semânticas

Background and objectives

The interactive approach of a journal club has been described in the medical education literature. The aim of this investigation is to present an assessment of journal club as a tool to address the question whether residents read more and critically.

Methods

This study reports the performance of medical residents in anesthesiology from the Clinics Hospital – University of São Paulo Medical School. All medical residents were invited to answer five questions derived from discussed papers. The answer sheet consisted of an affirmative statement with a Likert type scale (totally disagree–disagree–not sure–agree–totally agree), each related to one of the chosen articles. The results were evaluated by means of item analysis – difficulty index and discrimination power.

Results

Residents filled one hundred and seventy three evaluations in the months of December 2011 (n = 51), July 2012 (n = 66) and December 2012 (n = 56). The first exam presented all items with straight statement, second and third exams presented mixed items. Separating “totally agree” from “agree” increased the difficulty indices, but did not improve the discrimination power.

Conclusions

The use of a journal club assessment with straight and inverted statements and by means of five points scale for agreement has been shown to increase its item difficulty and discrimination power. This may reflect involvement either with the reading or the discussion during the journal meeting.