Iron supplementation in female blood donors deferred by copper sulfate screening

Female blood donors with low hematocrit levels detected by copper sulfate screening were selected randomly to receive either 75 mg of iron per day, as ferrous gluconate, or a calcium phosphate placebo. Their ferritin, serum iron, total iron-binding capacity, zinc protoporphyrin, and hemoglobin values, as well as their suitability to donate blood, were determined initially (Visit 1) and at four follow-up visits (Visits 2-5). By the second visit, the serum ferritin and iron values of donors receiving iron supplementation differed significantly from those of donors receiving placebo. By the fifth visit, a less marked but significant increase in hemoglobin had occurred in the iron group, but not in the placebo group. At no time was there a significant difference between the groups' suitability to donate blood, with each group donating at almost half of their visits. The authors conclude that iron supplementation at this dose level in deferred female blood donors improves their iron status and hemoglobin levels, but does not significantly increase their suitability to donate blood as compared with the suitability of placebo-treated donors.     

N-甲基-D-天冬氨酸受体在缺氧缺血性脑损伤新生大鼠脑海马中的远期表达

目的:观察新生大鼠缺氧缺血性脑损伤后,海马发育过程中N-甲基-D-天冬氨酸受体的远期表达变化。方法:实验于2006-03/06在解放军第三军医大学新桥医院中心实验室完成。选用新生7日龄SD大鼠72只,按随机数字表法分为缺氧缺血性脑损伤组和假手术组,每组36只。各组又分为生后15d(n=6)、22d(n=6)、29d(n=6)、36d(n=12)及43d(n=6)5个时相点。①参照Rice法通过结扎7日龄大鼠左侧颈总动脉,吸入氧气体积分数为0.08的氮氧混合气,制成缺氧缺血性脑损伤模型,出现自发或夹尾左旋则证明模型制作成功。假手术组仅切开颈部皮肤,暴露左侧颈总动脉。②应用免疫组织化学法检测缺氧缺血后不同时点两组大鼠脑海马CA1区N-甲基-D-天冬氨酸受体NR1亚单位的表达(n=6),测量平均灰度值,灰度值越低,蛋白表达越强;生后36d时相点大鼠(n=6)利用Morris水迷宫测定学习记忆能力;最后应用电镜观察生后36d大鼠海马突触结构。结果:72只大鼠,全部进入结果分析,无脱失。①生后22-43d缺氧缺血性脑损伤组大鼠(缺氧缺血后15-36d)脑海马CA1区NR1平均灰度值分别为167.69±6.48,174.57±4.81,179.30±5.92,176.50±5.93,均显著高于同日龄假手术组148.96±4.91,151.17±6.37,152.06±9.86,156.32±6.86(P均<0.01)。②Morris水迷宫实验中,缺氧缺血性脑损伤组大鼠逃避潜伏期显著长于假手术组(48.87±9.47)s,(11.97±2.20)s,(P<0.01);原平台象限游泳距离/总游泳距离的百分比显著低于假手术组(14.45±3.85)%,(62.20±8.74)%(P<0.01)。③生后36d(缺氧缺血后29d),透射电镜下缺氧缺血性脑损伤组大鼠患侧海马突触后膜致密物较假手术组明显减少。结论:新生大鼠缺氧缺血性脑损伤后期存在海马N-甲基-D-天冬氨酸受体的表达下调,可能对大鼠远期空间学习记忆产生一定影响。     

Evaluation of the Atrial Evoked Response for Capture Detection with High-Polarization Leads

AutoCapture™ based on the evoked response can be confounded by electrode polarization. In this study, polarization was measured in human subjects who had chronic atrial leads. The aim of the study was to determine whether electrode polarization can be measured using a time integral atrial evoked-response integral (AERI) of the negative portion of the atrial paced ER evoked-response signal and to determine whether high-polarization atrial leads unsuitable for AutoCapture™ can be identified a priori. Atrial intracardiac-electrogram (IEGM) signals from 39 patients with implanted pacemakers were recorded and analyzed. The signals were recorded during conventional atrial-threshold searches. A total of 221 atrial-capture thresholds were recorded, ranging from 0.25 to 2.75 V with a mean of 0.79 V. Each evoked response was evaluated using the AERI in a 36 ms window following the 0.4 ms atrial stimulus. The polarization was estimated as a linear function of stimulus voltage using the evoked-response signal integral of captured beats identified on the IEGM. The 221 threshold-search datasets were obtained using leads with eight different electrode materials. Polarization could be measured using AERI as a function of stimulus voltage. Furthermore, this polarization measure can be used to identify high-polarization leads, which are ill suited for the atrial AutoCapture™ algorithm.     

Optimizing the Geometry of Implantable Leads for Recording the Monophasic Action Potential with Fractally Coated Electrodes

This study investigates the influence of various lead geometry on intracardial signals like the monophasic action potential (MAP) to optimize the geometry of implantable MAP leads. The experimental results were compared with a field theoretical approach to the origin of MAP from the transmembrane potential (TAP). During the experiments several lead geometries (tip surface: 1.3 to 12 mm²; tip-ring distance: 0.8 mm to 25 cm; ring surface: 1.8mm² to 40 mm²) were investigated in endo- and epicardial positions in 12 dogs (17±9 kg). The electrodes were fixed passively (tines) or actively (screws). MAP was recorded during several interventions and correlated with MAP measured using an Ag-AgCl MAP catheter. The experimental results showed that small tips provided high MAP amplitudes with less pressure. No difference was observed using active and passive fixations. A tip-ring distance smaller than 5 mm with a ring surface smaller than the tip (<5 mm²) avoided artifacts in the repolarization course. For the theoretical approach the quasistatic, anisotropic bidomain model was calculated in smalt unity volumes V_i where the TAP φ_m was constant and represented by the current density J. Two solutions for electrode positions at and outside the heart were achieved. By superposition of each solution φ_ei the summed potential at the electrode position was calculated. The theoretical findings show in good correlation with the experimental results that a larger distance than 10 mm leads to distortions in repolarization course by signals proportional to φ_out.     

Blood loss and replacement in total hip arthroplasty: a multicenter study. The Preoperative Autologous Blood Donation Study Group

To determine blood loss, the number of transfusions, and the hemoglobin levels achieved in patients via transfusion in the course of total hip arthroplasty, 324 patient records from 1987 through 1989 were reviewed at three university and three community hospitals. Calculated blood loss was 3.2 +/- 1.3 units in primary procedures and 4.0 +/- 2.1 units in revision procedures (mean +/- SD). Of 777 red cell units transfused, 455 (59%) were autologous units. Transfused patients received 2.0 +/- 1.8 units for primary procedures and 2.9 +/- 2.3 units for revision procedures (mean +/- SD). The maximum number of units given to 95 percent of the transfused patients was 4 for primary procedures and 6 for revision procedures. The mean postoperative hemoglobin level after all transfusions was 103 to 110 g per L, regardless of patient age group of physical status, autologous donor status, or hospital. No difference in length of hospital stay was observed for patients less than 65 years old with hemoglobin concentrations of 80 to 139 g per L at discharge.     

机械力学对体外骨髓间充质干细胞的影响

目的:分析力学刺激体外骨髓间充质干细胞所产生增殖分化等生物学效应的影响及其力化学信号转导途径。资料来源:因特网上检索PubMed数据库中2000-01/2006-06期间有关力学刺激对骨髓干细胞作用效应进展的英文文章,检索词“stem cel1,marrow mesenchymal stem cells,mechanical stimulation,stress”,同时检索CNKI中国知网医学文献数据库2000-01/2006-06期间的相关文章,检索词为“干细胞、骨髓间充质干细胞、机械刺激、应力”。资料选择:对资料进行筛选,选取相关文章查找全文。纳入标准:①骨髓间充质干细胞相关生物学特性。②体外细胞加载的应力分类及相应力学装置的特点。③应力对细胞影响的研究。④能获取文章的全文。排除标准:①较陈旧的文献。②重复研究。资料提炼:共收集关于86篇体外骨髓干细胞及力学干预的相关文献。其中30篇符合纳入标准。资料综合:①骨髓干细胞具有高度增殖及多向分化能力,可通过体外培养、干预作为细胞组织工程的理想种子细胞。②力学刺激是体外调节细胞生物学效应的重要途径,其中力学分类有:流体切应力、静止压应力、张应力、离心力以及单个细胞的吸吮力等,介绍各种力以及相应的力学装置的特点。③骨髓干细胞加载各种应力干预后产生的生物学效应,以及细胞应力学刺激的机制、信号转导途径。结论:力学刺激可影响骨髓间充质干细胞生物学特性,在适当的力学刺激条件下,促进细胞的增殖与分化,为骨组织工程提供新的技术手段,同时也为临床应用牵拉成骨的骨再生过程提供理论依据。     

A near-fatal reaction during granulocyte transfusion of a neonate

Although reactions to granulocyte transfusions in neonates are rarely reported, we observed a near-fatal pulmonary reaction, presumably due to white cell antibodies, in a neonate with Rh hemolytic disease. The hemolytic disease was being treated with exchange transfusions, and at 2 days after the infant's birth, bacterial sepsis was suspected and granulocyte transfusions were begun. The first granulocyte transfusion (Day 3) was uneventful. Five minutes after the beginning of the second granulocyte transfusion (Day 4), severe respiratory distress, hypotension, bradycardia, cyanosis, and acidosis suddenly occurred. The infant's serum obtained after the reaction contained granulocytotoxic and B-lymphocytotoxic antibodies that reacted with leukocytes from the second granulocyte donor. Antibodies could not be detected either in the initial infant serum or in maternal serum. However, an antileukocyte antibody was present in the serum of a parous woman donor. We used plasma from this woman to prepare reconstituted whole blood for the exchange transfusion that we performed immediately preceding the second granulocyte transfusion. Despite the sequence of events, an irrefutable cause-and-effect mechanism could not be established because the properties of the donor and neonatal antibodies were similar, but not identical. However, this catastrophic event emphasizes both the potential for adverse effects of granulocyte transfusions in neonates and the need for caution when transfusing blood from parous women.     

Dual Chamber Pacing in Hypertrophic Obstructive Cardiomyopathy: Beneficial Effect of Atrioventricular Junction Ablation for Optimal Left Ventricular Capture and Filling

Clinical improvement with dual chamber pacing bas largely been reported in patients suffering from hypertrophic obstructive cardiomyopathy and mainly attributed to the reduction of the subaortic pressure gradient. To be effective, pacing must induce a permanent and complete capture of the LV. In two patients of our collective, symptoms (angina and dyspnea NYHA Class III and/or syncopes) persisted or relapsed despite pacing. This was related to the inability to obtain full LV capture due to a too-short native PR interval. RF ablation of the AV junction was therefore performed in botb patients, resulting in permanent AV block in one and prolonged PR interval up to 310 ms in the second. Pacing was thereafter associated with an immediate and significant clinical improvement related to permanent LV capture, whatever the patient's activity. After RF ablation, the AV delay was set up to induce the best LV filling, as assessed by Doppler analysis of mitral flow. Our observations suggest that RF ablation or modification of the AV junction can be a successful procedure in some patients with residual or recurrent symptoms, when the latter result from a loss of capture or from the inability to program an AV delay tbat does not compromise the active component to LV filling. Doppler echocardiography is a simple and effective mean to assess the hemodynamic effect of AV interval modulation in this setting.     

慢性失眠症患者的思维特点

目的:观察慢性失眠症患者的认知行为特征和其症状的产生及发展的关系,分析慢性失眠症患者的思维特点。方法:随机抽取北京中医药大学国医堂睡眠障碍门诊2004-01/07失眠症患者90例和配对睡眠正常者90人进行问卷调查,包括匹兹堡睡眠质量指数问卷、关于睡眠的非功能性的信念和态度量表修订版问卷以及思维控制问卷。匹兹堡睡眠质量指数问卷包括7个因子,每个因子按0～3等级记分,得分越高表示睡眠质量越差。关于睡眠的非功能性的信念和态度量表修订版由10个条目组成,5级评分,得分越高表示关于睡眠的非功能性的信念和态度越多。思维控制问卷由30个条目组成,包括6个纬度:认知转移、行为转移、社会支持、担心、惩罚和再评价,每个纬度的得分越高表示使用此种思维控制的方式越多。结果:发放问卷180份,回收完整问卷158份,有效率87.8%。最终病例组和对照组各79人,进入结果分析。①慢性失眠症患者关于失眠的短期影响、长期影响和对于睡眠的控制的非功能性的态度和信念得分均高于对照组(19.48±2.90,14.14±5.87;11.06±1.79,8.11±2.74;7.82±1.44,5.01±2.07;t=9.86,7.25,8.01,P<0.01)。②慢性失眠症患者使用担心和惩罚的思维控制方式得分高于睡眠正常组(10.7±2.6,8.5±2.9;11.6±2.8,9.0±3.1;t=5.08,5.43,P<0.01)。③关于睡眠的非功能性的信念和态度与担心和惩罚的思维控制方式呈正相关(r=0.41,0.24,P<0.01)。结论:对于失眠症患者进行认知行为治疗时,要注意纠正失眠症患者关于睡眠的非功能性的信念和态度,并指导失眠症患者学习有效的思维控制方式。     

低氧暴露对运动性贫血大鼠抗氧化能力的影响

目的:观察低氧暴露对运动性贫血大鼠某些抗氧化酶的影响,探讨低氧条件下抗氧化系统的反应是否有利于改善运动性贫血。方法:实验于2005-07/09在广东省高等学校运动生物化学教学重点实验室完成。选择6周龄健康雄性SD大鼠40只,均为运动性贫血动物模型,大鼠适应环境1周后采用6周递增负荷跑台运动方式建立。按随机数字表法分为1h低氧暴露组、2h低氧暴露组和间歇性低氧暴露组、常氧恢复组,每组10只。采用人工常压低氧环境,低氧浓度控制在14.5%左右,按分组每天在常压低氧舱进行1,2h和间歇性低氧暴露(低氧暴露1h,中间间歇3h,再低氧暴露1h),其余时间在舱外常氧中自由活动,每周6d,持续3周。常氧恢复组大鼠在常氧中自由活动。3周后测试运动性贫血大鼠血清丙二醛含量、超氧化物歧化酶活性和血浆过氧化氢酶、谷胱甘肽过氧化酶活性。结果:纳入动物40只,均进入结果分析。①低氧暴露3周后1h低氧暴露组、2h低氧暴露组、间歇性低氧暴露组血清丙二醛含量均显著低于常氧恢复组[分别为(2.62±0.16),(2.60±0.22),(2.55±0.06),(3.36±0.34)μmol/L,P<0.05]。②低氧暴露3周后血清超氧化物歧化酶和血浆谷胱甘肽过氧化酶、过氧化氢酶活性均高于常氧恢复组,2h低氧暴露组与常氧恢复组比较差异有显著性意义[分别为(4239.68±169.53),(3190.30±339.40)μkat/L;(20622.46±2002.07),(15556.44±607.79)μkat/L;(50.01±6.67),(35.17±4.50)μkat/L,P<0.05]。③各低氧暴露组间除2h低氧暴露组血清超氧化物歧化酶活性显著高于1h低氧暴露组外[分别为(4239.68±169.53),(2126.41±161.20)μkat/L,P<0.05],其他指标组间差异无显著性意义(P>0.05)。结论:低氧暴露可提高运动性贫血大鼠机体的抗氧化能力,有利于促进运动性贫血的恢复。