Superfine Magnetic Resonance Imaging of the Cerebrovasculature Using Self‐Assembled Branched Polyethylene Glycol–Gd Contrast Agent

Magnetic resonance angiography is an attractive method for the visualization of the cerebrovasculature, but small‐sized vessels are hard to visualize with the current clinically approved agents. In this study, a polymeric contrast agent for the superfine imaging of the cerebrovasculature is presented. Eight‐arm polyethylene glycol with a molecular weight of ≈17 000 Da conjugated with a Gd chelate and fluorescein (F‐8‐arm PEG‐Gd) is used. The relaxivity rate is 9.3 × 10⁻³m ⁻¹ s⁻¹, which is threefold higher than that of free Gd chelate. Light scattering analysis reveals that F‐8‐arm PEG‐Gd is formed by self‐assembly. When the F‐8‐arm PEG‐Gd is intravenously injected, cerebrovasculature as small as 100 µm in diameter is clearly visualized. However, signals are not enhanced when Gd chelate and Gd chelate‐conjugated 8‐arm PEG are injected. Furthermore, small vasculature around infarct region in rat stroke model can be visualized. These results suggest that F‐8‐arm PEG‐Gd enhances the MR imaging of cerebrovasculature.     

Characterization of the Penetration of the Blood–Brain Barrier by High-Performance Liquid Chromatography (HPLC) Using a Stationary Phase with an Immobilized Artificial Membrane

The biological activity of drugs on organisms is associated with the pharmacokinetic properties, such as the ability to penetrate through environments of varying polarity such as cellular organelles. In this area, particular attention is turned to the physicochemical properties that determine the potential of drugs to pass across the blood–brain barrier and thus to act on the central nervous system. In this study, special effort has been devoted to the simulation of passive diffusion of seven drugs (propranolol, ibuprofen, atenolol, promazine, chlorpromazine, imipramine, and desipramine) through the blood–brain barrier by high-performance liquid chromatography (HPLC) using a column with an immobilized artificial membrane. Gradient reverse elution was used to develop a linear correlation model for the capacity factors k_IAM and the in vivo logarithmic values of brain-to-blood drug concentration ratios (log BB) with R of 0.9851. Eleven additional pharmaceuticals were determined by the same method to predict their potential to penetrate the blood–brain barrier. The reported analytical method represents an alternative tool for rapid and noninvasive assessment of the absorption properties of chemicals, especially for the development of novel drugs. The retention of the studied compounds on the immobilized artificial membrane column was also compared with three other C18-based stationary phases. Herein, the results of the HPLC determination of drugs using an immobilized artificial membrane are briefly discussed with respect to a general application of the method for evaluating a broader spectrum of pharmaceutical compounds.     

胸腺五肽对老年重型脑损害病人T淋巴细胞亚群的影响

为了探讨胸腺五肽对重型脑损害病人T淋巴细胞亚群的影响,从湛江市第二人民医院1999年1月至2005年1月住院的重型脑损害病人90例中,随机分为胸腺五肽治疗组和对照组,观察了两组T淋巴细胞亚群的变化,并评价其临床疗效。结果表明,对照组的n(CD4 )/n(CD8 )比值显著低于治疗组(P<0.01);治疗组的死亡率为5%,显著低于常规治疗组(P<0.01)。结果表明,胸腺五肽可显著改善重型脑损害病人的免疫力,降低死亡率,有推广应用价值。     

Concurrent determination of thalidomide in rat blood, brain and bile using multiple microdialysis coupled to liquid chromatography

A rapid and sensitive system of liquid chromatography coupled with microdialysis was developed for the simultaneous determination of unbound thalidomide in rat blood, brain and bile for pharmacokinetic study. Microdialysis probes were concurrently inserted into the jugular vein toward the right atrium, the brain striatum and the bile duct of the anesthetized Sprague-Dawley rats for biological fluid sampling after the administration of thalidomide (5 mg kg(-1)) through the femoral vein. Thalidomide and dialysates were separated using a Zorbax ODS C(18) column and a mobile phase comprising acetonitrile-methanol-0.1 mm 1-octanesulufonic acid (32:3:65, v/v/v, pH 5.3) at flow rate of 1 mL min(-1). The UV wavelength was set at 220 nm. The concentration-response relationship was linear (r(2)>0.995) over a concentration range of 0.025--25 microg mL(-1). The intra-assay and inter-assay precision and accuracy of thalidomide fell within 7%. The average in vivo recoveries were 0.31+/- 0.02,0.046+/- 0.004 and 0.57+/- 0.02 (n=6), respective to the dialysates of blood, brain and bile, with thalidomide at concentrations 2, 5 and 10 microg mL(-1). The disposition of thalidomide in the blood, brain and bile fluid suggests that there is a rapid thalidomide exchange and equilibration between the blood and brain systems. In addition, thalidomide undergoes hepatobiliary excretion.     

铬,硒,镉,锰与心脑血管疾病

通过对５０例心脑血管疾病病人及５０例健康对照组血中微量元素铬、硒、镉、锰的检测分析证实，心脑血管疾病病人血清Ｃｒ、Ｓｅ含量下降，Ｃｄ含量未见明显升高，并进一步探讨了这些微量元素与心脑血管疾病的发生发展的关系及其临床意义。     

Minor and trace element contents in pituitary gland of “normal” humans: an evaluation of analytical data

In the study of trace elements in the different human brain areas, a critical evaluation of the values available in the literature is of great importance in attempting to establish reliable baseline levels, i.e., Reference Values (RVs) for toxicological assessment studies.This paper reviews the published values of minor and trace elements in the pituitary gland (hypophysis) of “normal” humans.Eighteen published papers are taken into account, 15 of which refer to the entire gland, whereas in three of them, only the adenohypophysis is considered.It turns out that essential elements such as Cu, Fe, Se and Zn were more frequently determined, whereas As, Br, Ca, Co, Cr, Cs, K, Mg, Mn, Ni and Rb were seldom investigated.Mercury was determined by several authors because of the concern caused by Hg release from dental amalgam fillings.Most values were obtained by Neutron Activation Analysis (NAA), which appears to have played a pioneer role in this field.Literature data on trace element levels in pituitary gland are at present insufficient to establish RVs; rather, they can be considered only as indicative values.Future investigations based on large populations of control subjects, with standardization of the preanalytical factors and the use of fit-for-purpose Standard or Certified Reference Materials (SRMs, CRMs) should therefore be envisaged.     

原发性脑蛛网膜下腔出血的临床分析

为探讨原发性脑蛛网膜下腔出血的诊断和治疗，对1993～2003年住院的10例原发性脑蛛网膜下腔出血患者进行了回顾性分析。结果表明，10例患者中，5例描述有爆裂样头痛，2例头颅CT检查阴性，经腰穿检查确诊。治愈2例，占20％；好转3例，占30％；死亡5例，占50％。提示爆裂样头痛是主要的、但非特异的特征，所有患者均须行CT扫描，如CT阴性则应行腰穿检查。原发性脑蛛网膜下腔出血的死亡率很高，进一步探讨其诊断和治疗仍有积极的临床意义。     

2.5次微分溶出伏安法同时测定人脑中铜,铅,镉,锌

本文通过硝酸－硫酸混合酸消化脑样，在０．０３ｍｏｌ／ＬＨＣｌＯ４底液中，采用悬汞电极２．５次微分阳极溶出伏安法同时测定人脑中铜、铅、镉、锌四种微量元素。在选定的实验条件下，所述元素的浓度在５～１００ｎｇ／ｍＬ范围内与峰高成线性关系。用于人脑中铜、铅、镉和锌的分析，其相对标准偏差分别为６．５％、１０．５％、１２．７％和３．１％，其回收率为９８．０％、９４．０％、１０２．０％和１０４．０％。     

Preparation of new technetium-99m NNS/X complexes and selection for brain imaging agent

Quantification of regional cerebral blood flow(rCBF) plays an important role in the diagnosis ofvarious cerebrovascular and neurological diseases. Innuclear medicine, brain perfusion imaging can providesituation of whole or regional cerebral blood flowperfusion (CBF or rCBF) to neurologists, help to findabnormality of cerebral blood flow before cere-brovascular and neurological diseases induce patho-logical changes in configuration or structure of brain.They offer important information for …