Thrombospondin mediates the cytoadherence of Plasmodium falciparum- infected red cells to vascular endothelium in shear flow conditions

Cerebral malaria is thought to involve specific attachment of Plasmodium falciparum-infected knobby red cells to venular endothelium. The nature of surface ligands on host endothelial cells that may mediate cytoadherence is poorly understood. We have investigated the effects of soluble thrombospondin, rabbit antiserum raised against thrombospondin, and human immune serum on cytoadherence of parasitized erythrocytes in ex vivo mesocecum vasculature. Preincubation of infected red cells with soluble thrombospondin or human immune serum inhibits binding of infected red cells to rat venular endothelium. Infusion of the microcirculatory preparation with rabbit antithrombospondin antibodies before perfusion of parasitized erythrocytes also resulted in decreased cytoadherence. In addition, incubation of infected cells with human immune sera obtained from malaria patients significantly inhibited the observed cytoadherence. Our results indicate that thrombospondin mediates binding of infected red cells to venular endothelium and may thus be involved in the pathogenesis of cerebral malaria.     

复合自适应滤波器用于体感诱发电位信噪比的提高

本研究以可靠、快速提取体感诱发电位为目标,试图解决相干叠加方法既费时又不能反映体感诱发电位时变特征的缺点。运用以自适应噪声减法器和自适应增强器为基础构造的复合自适应滤波器提取体感诱发电位。仿真实验表明,运用复合自适应滤波器可实现从强噪声背景中快速提取体感诱发电位,能更快地识别体感诱发电位的潜伏期及幅值,并且系统性能稳定。     

离子色谱法同时测定葡萄糖酸钙及其杂质(Cl-,SO42-)的含量

本文采用Waters ILC-1离子液相色谱仪,IC-PAK A50×4.6mm色谱柱,pH6.61×10^-3mol/L邻苯二甲酸溶液为流动相,430型电导检测器检测,由外标法和外标单点校正法同时测定了葡萄糖酸钙及其杂质(Cl^-,SO₄^2-)的含量。方法简便、快速,测定结果与中国药典法一致。外标法和外标单点校正法测定Cl^-,SO₄^2-的平均回收率为100.8%和100.2%,相关系数分别为0.9951(n=8)和0.9961(n=8)。     

Dorsal lunate tilt (DISI configuration): sign of scaphoid fracture displacement

Excessive dorsiflexion (dorsal tilting) of the lunate on a lateral wrist radiograph can be an important sign of carpal injury. Lunate dorsiflexion is a well-recognized sign of an intercarpal ligamentous injury pattern known as dorsal intercalated segment instability (DISI). It is less well recognized that excessive dorsal tilting of the lunate (DISI configuration) can also be produced by displacement of a scaphoid waist fracture. Since the management and prognosis of displaced scaphoid fractures may be quite different from those for nondisplaced fractures, radiologists can make an important contribution by recognizing dorsal tilting of the lunate and appreciating that it may be an important, indirect sign of scaphoid fracture displacement, which may not be directly visualized with standard wrist radiography. In this setting, computed tomography or complex motion tomography may be helpful for further evaluation of the scaphoid fracture.     

Human T cell responses against the major cysteine proteinase (cruzipain) of Trypanosoma cruzi: role of the multifunctional alpha 2- macroglobulin receptor in antigen presentation by monocytes

Chagas' disease patients (CDP) develop both humoral and cellular immune responses against the major cysteine proteinase (cruzipain) from Trypanosoma cruzi. Here we demonstrate that complexes formed by cruzipain and alpha 2-macroglobulin (alpha 2M) are efficiently internalized by human monocytes, and that this process results in enhanced presentation of cruzipain peptides to CD4+ T cells from CDP. Purified or serum alpha 2M binds to polymorphic cruzipains, but only a fraction of the proteinases become covalently linked. Once bound to alpha 2M, fluorescein-labeled cruzipain (FITC-cruzipain) or [125I]cruzipain were more efficiently internalized by normal peripheral blood mononuclear cells (PBMC) or monocytes; this effect was abolished by (I) pre-treating the cells with receptor-associated protein (rRAP), a known antagonist the of alpha 2M receptor (alpha 2MR/LRP), and (II) inactivating [125I]cruzipain's active site prior to the reaction with alpha 2M, indicating that the exposure of receptor binding sites on alpha 2M complexes required bait region cleavage. We then sought to determine if the alpha 2MR/LRP-dependent uptake of alpha 2M:cruzipain by monocytes resulted in increased CD4+ T cell responses of PBMC-CDP (n = 13). These effects were only revealed after depletion of CD19+ B lymphocytes from PBMC-CDP; the threshold of T cell stimulation was far lower in cultures stimulated with alpha 2M:cruzipain, as compared to antigen alone. Myocardial specimens from CDP with chronic myocardiopathy (three necropsies) were analyzed by immunohistochemistry with mAb anti-cruzipain or anti-alpha 2MR/LRP (CD81+). Extracellular depots of cruzipain were localized amidst inflammatory mononuclear infiltrates, part of which contained CD91+ macrophage-like cells. Ongoing studies should clarify if T. cruzi cysteinyl proteinases play a role in the pathogenesis of Chagas' heart disease.      

Anaesthesia for paediatric cardiac MRI

Background: General anaesthesia (GA) for cardiac magnetic resonance imaging (MRI) in patients with congenital heart disease (CHD) is challenging for the anaesthesiologist.     

Muscular sufficiency, serum protein, enzymes and bioenergetic studies (31-phosphorus magnetic resonance spectroscopy) in chronic malnutrition

Muscle sufficiency was significantly lower in 1336 children with chronic malnutrition of moderate to severe degree. Eighteen children with a chronic moderate degree of malnutrition and 8 well-nourished, age-matched controls were selected for biochemical and 31-phosphorus magnetic resonance spectroscopy (31 -P MRS) studies. The results showed that: (a) serum total protein, albumin, iron, calcium and inorganic phosphate were similar in both groups; (b) serum enzyme levels were significantly increased in the malnourished group; (c) 31-P MRS showed significantly higher means for total ATP, β-ATP, a-ATP and inorganic phosphate for the malnourished compared to the control group. In chronic malnutrition, proteins are maintained by degradation in muscle resulting in release of amino acids and enzymes. 31-P MRS studies showing increases in total ATP, β-ATP and inorganic phosphate and a decrease in phosphocreatine suggest that ATP is maintained at the cost of phosphocreatine.     

高效液相色谱法测定血浆中洛美沙星浓度及其在人体内药代动力学

建立了人血浆洛美沙星的反相离子对高效液相色谱测定方法。该法简便易行,精密度好,方法回收率95～102%,日内、日间RSD为2.1～7.8%,血药浓度在0.125～5.012 μg/ml范围内呈线性关系,相关系数0.9998,当S/N=2时,最小检测浓度为25 ng/ml。健康志愿者口服400 mg洛美沙星,药代动力学过程符合一室模型,消除相半衰期为5.5 h。