Variation in fetal hemoglobin parameters and predicted hemoglobin S polymerization in sickle cell children in the first two years of life: Parisian Prospective Study on Sickle Cell Disease

Intracellular hemoglobin S (HbS) polymerization is most likely to be the primary determinant of the clinical and biologic manifestations of sickle cell disease (SCD). Fetal hemoglobin (HbF) does not enter the HbS polymer and its intracellular expression in sickle erythrocytes inhibits polymerization. HbF levels, high at birth but decreasing thereafter, protect the newborn from the clinical manifestations of this hemoglobinopathy. We have measured the sequential changes in HbF, F reticulocytes, and F cells in the first 2 years of life in 25 children with SCD and compared the results with those obtained in 30 normal children (AA). We have also calculated HbF per F cell (F/F cell), the preferential survival of F cells versus non-F cells, as measured by the ratio F cells versus F reticulocytes (FC/FR) and polymer tendency at 40% and 70% oxygen saturation. HbF levels decreased from about 80.4% +/- 4.0% at birth to 9.2% +/- 2.9% at 24 months. During this time, we observed a regular decrease of the F reticulocytes and the F cells. The kinetics of the decline of F/F cell was comparable with the decline of HbF, rapid from birth (mean, 27.0 +/- 3.6 pg) to 12 months of age (mean, 8.5 +/- 1.5 pg) and then slower from 12 to 24 months of age (mean, 6.2 +/- 1.0 pg) in the SCD children. In the AA children, the decrease in HbF, due to changes in both numbers of F cells and F/F cell, was more precipitous, reaching steady-state levels by 10 months of age. Calculated values for mean polymer tendency in the F-cell population showed that polymerization should begin to occur at 40% oxygen saturation at about 3 months and increase progressively with age, whereas polymerization at 70% oxygen saturation would not occur until about 24 months. These values correspond to HbF levels of 50.8% +/- 10.8% and 9.2% +/- 2.9%, respectively, and F/F cell levels of 15.6 +/- 4.5 pg and 6.2 +/- 1.0 pg, respectively. In the non--F-cell population, polymerization was expected at birth at both oxygen saturation values. Three individuals had significantly greater predicted polymerization tendency than the remainder of the group because of early decreases in HbF. These individuals in particular, the remainder of the cohort, as well as other recruited newborns, will be studied prospectively to ascertain the relationship among hematologic parameters, which determine polymerization tendency and the various clinical manifestations of SCD.     

生理载荷条件下髋臼假体的疲劳破坏机制(上)

本文对生理载荷条件下(正常步态、爬楼梯和日常活动的混态载倚)骨水泥髋臼假体(牛髋骨试件)的失效机制进行研究.试验中利用髋关节仿真试验机施加生理载倚,利用人工仿真关节液来模拟体内生理环境,以测试髋臼假体的生命周期.在试验中通过微CT扫描仪观测并记载破坏的进程,并在试验结束后使用显微镜进行验证.结果表明,在所有载荷条件下,骨水泥-骨的界面松解是导致假体失效的原因,在体外环境条件下界面松解发生在髋臼窝中心的后上部区域,在体内生理环境下界面松解则发生在髋臼窝的所有区域.因此.模拟人体内部生理条件的试验环境是必需的,同时也确定髋臼假体的失效来自于力学和生物学因素的共同作用.     

沉香呋喃类立体异构体的气相色谱及气-质联用分析研究

采用GC及GC—MS方法,对沉香呋喃类中的三对差向异构体进行了成功的分离鉴定,确定了每对异构体的比例,建立了倍半萜类异构体的分析方法,从而有效地指导了合成反应,加快了合成的进度,为产物合成提供了可靠的依据。     

苄普地尔与山莨菪碱合用对心肌缺血再灌注损伤的保护作用

卡普地尔与山莨菪碱合用对结扎大鼠冠脉左室支造成心肌缺血再灌注损伤的保护作用。两药同时合用可降低缺血再灌性心律失常发生率;明显提高复灌后心肌超氧物歧化酶活性及显著减轻心肌超微结构损伤。表明两药合用有协同作用,较单用苄普地尔或山莨菪碱疗效好。     

阿司匹林与埃索美拉唑合用较氯吡格雷减少高危患者再次溃疡出血的发生

问题：在有阿司匹林诱发溃疡出血史的患者中，用氯毗格雷预防溃疡出血复发，是否不次于小剂量阿司匹林加埃索美拉唑？[编者按]     

The hereditary pancreatitis gene maps to long arm of chromosome 7

Hereditary pancreatitis (HP) is an autosomal dominant disorder with incomplete penetrance characterized by recurring episodes of severe abdominal pain often presenting in childhood. Although this disorder has only been recently described, about 100 families have been documented worldwide. The pathophysiology of this disorder is unknown. Here, a large French family of 147 individuals (47 of whom were affected) from a four-generation kindred with HP has been examined and a genome segregation analysis of highly informative microsatellite markers has been performed. Linkage has been found between HP and six chromosome 7q markers. Maximal two point lod scores between HP and D7S 640, D7S 495, D7S 684, D7S 661, D7S 676 and D7S 688 were 4.00 (theta = 0.143), 5.85 (theta = 0.143), 4.91 (theta = 0.156), 8.58 (theta = 0.077), 8.28 (theta = 0.060), 4.40 (theta = 0.169), respectively. Multipoint linkage data combined with recombinant haplotype analysis indicated that the most likely order is: D7S 640-D7S 495-D7S 684-D7S 661-D7S 676-D7S 688, with the HP gene situated in the underlined region. As in all families reported in the literature, the clinical presentation of the disease is identical to the presentation of sporadic cases, one could expect that the knowledge of the HP gene could be a clue to pancreatitis in general. Based on its map position, this is the first step towards the positional cloning of the Hereditary Pancreatitis Gene (HPG).