血清中罗红霉素浓度反相高效液相色谱测定法的改进

目的　对测定血清中罗红霉素浓度的高效液相色谱法进行改进。方法　其改进要点是 :采用Penom enex L una C1 8分析柱 (5 μm,15 0 m m× 4.6 m m) ,以乙腈 -甲醇 - 0 .0 5 m ol/ L 磷酸 (39∶ 19∶ 42 ,用氨水调 p H至7.2 )为流动相 ,克拉霉素作内标。血清样品碱化后用二氯甲烷提取浓集 ,再经进一步纯化后进样 ,在 2 10 nm波长处检测 ,按内标法定量。结果　本法与原方法的标准曲线线性范围分别为 0 .2 5～ 32 mg/ L 和 0 .2 5～ 16 m g/ L,最低检出量分别为 5 ng和 2 0 ng,罗红霉素保留时间分别为 5 .0分钟和 13.2 7分钟 ,日内 RSD小于 2 .5 %和 7.5 % ,日间RSD小于 3.0 %和 5 .5 % ,萃取回收率和方法回收率一致。结论　本法与原法相比具有快速简便、灵敏准确等优点     

Concentrating stroke care provision in the Czech Republic: The establishment of Stroke Centres in 2011 has led to improved outcomes

This article describes policy processes that have led to the re-organisation of stroke care in the Czech Republic since 2011, which has been part of a broader process of care concentration in several medical fields. Currently, stroke care is provided by 13 Comprehensive and 32 Primary Stroke Centres. The paper explains factors that supported the reform implementation, reviews implications, and discusses future challenges.Mandatory reporting of quality indicators, the introduction of a benchmarking system, integration with pre-hospital emergency care, and the introduction of countrywide patient triage have supported more timely treatment for stroke patients and better quality of care. Data from the Stroke Care Quality Indicators of the Czech Stroke Society show positive trends in many areas: the number of patients treated with intravenous thrombolysis quadrupled in eight years, with 26.4 % of all acute stroke patients receiving thrombolysis in 2018. Czech Republic now ranks third in Europe in the number of thrombolysis per population and second in the number of mechanical thrombectomies per population. The Czech experience provides an example of positive outcomes of concentrated stroke care, while highlighting the importance of proper implementation processes. In particular, it is essential to involve stakeholders and to provide reputational incentives through continuous benchmarking.     

踏跳瞬间足后部骨骼的三维有限元分析

目的建立足部三维有限元模型,对足后部骨骼在踏跳中的应力分布进行分析。方法应用CT扫描和CAD/CAM软件处理,建立足后部骨骼三维模型。通过对背跃式跳高踏跳的足底压力测量和逆向肌肉力量计算,确定载荷约束条件,并进行有限元计算。结果获得了踏跳瞬间,跟骨、距骨、舟骨等易损伤部位的生物力学响应和应力分布,发现跟骨后距关节,距骨背面均为应力集中处。结论本研究建立的模型可用于足后部骨骼生物力学研究,为踏跳中的运动损伤力学机理提供数据。     

Cross-desensitization Reveals Pharmacological Specificity of Excitatory Amino Acid Receptors in Isolated Hippocampal Neurons

Ionic currents elicited by excitatory amino acids were studied, using the concentration clamp method, in enzymatically isolated rat hippocampal neurons. Cross-desensitization between the responses to various agonists was applied to separate the activity of two types of receptors, N-methyl-d-aspartate (NMDA) and non-NMDA. NMDA receptors were selectively activated by NMDA, l- and d-aspartate, d-glutamate and quinolinate. Kainate and alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate appeared to be selective, and quisqualate relatively less selective non-NMDA agonists, acting on the same receptor type. l-Glutamate, l- and d-homocysteate activated both receptor types. It is supposed that two receptor sites, activation site and desensitization site, control the action of agonists at the non-NMDA receptor. When examined in the cross-desensitization experiments, NMDA and non-NMDA receptors appear to be represented by the two homogeneous and independent receptor populations operating different ionic channels.     

Effects of low, subinhibitory concentrations of antibiotics on expression of a virulence gene cluster of pathogenic Escherichia coli by using a wild-type gene fusion

S fimbrial adhesins (Sfa) represent virulence factors of E. coli wild-type strains causing urinary tract infections and meningitis of the new born. In order to determine the influence of subinhibitory concentration of antibiotics on the expression of the sfa gene cluster, a wild-type strain carrying the lacZ gene, coding for the enzyme β-galactosidase fused to the sfa determinant was used. The expression of lacZ which was under the control of the sfa wild-type promoters, was now equivalent to the sfa gene expression of wild-type strain 536. With this strain the influence of subinhibitory concentrations of 28 antibiotics on the expression of the sfa determinant was studied. The expression was strongly suppressed by a treatment of the wild-type fusion strain by aztreonam, gentamicin, clindamycin and trimethoprim; the latter had a dramatic effect on sfa expression. It was further shown for clindamycin and trimethoprim that the reduction of sfa gene expression was dependent on the concentration of the antibiotics. In contrast imipinem, amphotericin B and rifampicin weakly stimulated sfa expression. We conclude that gene fusions between virulence-associated loci and indicator genes in wild-type pathogens are useful to study virulence modulation due to subinhibitory concentration of antibiotics on the genetic level.     

Sympathoinhibition by rilmenidine in conscious rabbits: involvement of α2-adrenoceptors

Summary Cardiovascular and sympathetic nervous system effects of the mixed ₂-adrenoceptor and imidazoline receptor agonist rilmenidine were studied in conscious rabbits chronically instrumented for the recording of the firing rate of renal sympathetic fibers. Separate experiments were carried out on pithed rabbits with electrically stimulated (2 Hz) sympathetic outflow. Drugs were administered intravenously in a cumulative manner.In conscious rabbits, rilmenidine 0.1, 0.3 and 1.0 mg kg^–1 dose-dependently lowered blood pressure, renal sympathetic nerve activity, heart rate and the plasma concentration of noradrenaline and adrenaline. The effect on blood pressure and plasma catecholamines was maximal after 0.3 mg kg^–1 whereas heart rate and renal sympathetic nerve activity decreased further after rilmenidine 1.0 mg kg^–1. Yohimbine 0.1 and 0.5 mg kg^–1, when injected subsequently, attenuated and at the higher dose abolished all effects of rilmenidine. The effects of rilmenidine were also antagonized by the ₂-adrenoceptor antagonist 2-(2,3-dihydro-2-methoxy-1,4-benzodioxin-2-yl)-4,5-dihydro-1H-imidazole HCl (RX821002; 0.1 and 0.5 mg kg^–1). Yohimbine 0.1 and 0.5 mg kg^–1 did not attenuate or attenuated only slightly the decrease of heart rate and renal sympathetic nerve activity produced by infusion of vasopressin. In pithed rabbits with electrically-stimulated sympathetic outflow, yohimbine 0.1 submaximally and yohimbine 0.5 mg kg^–1 maximally increased the plasma noradrenaline concentration.The experiments show by direct measurement of sympathetic nerve firing and plasma catecholamines that rilmenidine causes sympathoinhibition in conscious rabbits, presumably through central sites of action. The antagonism by yohimbine, at doses which are selective for ₂-adrenoceptors (vs. imidazoline receptors), demonstrates the involvement of ₂-adrenoceptors in the sympatho-inhibition.Correspondence to: B. Szabo at the above address     

血糖浓度增高对急性心肌梗塞预后的影响

目的:回顾性地了解无论是否伴有糖尿病,血糖浓度增高对急性心肌梗塞住院病死率及心梗后心衰、心源性休克的影响。方法:1990年1月～2000年10月我院心肌梗塞住院病人100例,将入院时血糖浓度<6.6mmol/L作为A组。入院时血糖浓度增高在6.6～11.1mmol/L为B组。入院时血糖浓度>11.1mmol/L为C组,分别计算各组发生心衰、心源性休克的百分率及住院病死率。结果:A组心衰发生率10.71％,心源性休克发生率3.57％,住院病死率3.57％;B组心衰发生率41.18％,心源性休克发生率29.41％,住院病死率26.47％;C组心衰发生率52.63％,心源性休克发生率31.58％,住院病死率26.32％。B组、C组心衰发生率、心源性休克发生率及住院病死率比A组明显增加,差异有显著性。而B组与C组心衰发生率、心源性休克发生率及住院病死率无显著性差异。结论:血糖浓度增高,心衰、心源性休克发生率及住院病死率明显增高。     

超滤膜分离技术在植酸酶浓缩中的应用

目的 利用超滤法在低温下操作,生物活性物质不易失活的特点,探讨超滤法代替薄膜蒸发法浓缩植酸酶发醇液的技术可行性,以降低能耗。方法 采用截留分子量为２００００的ＰＵ－２０Ｋ－ＰＳ管式超滤膜系统浓缩１～５批次的植酸酶发醇液,测定浓缩倍数、浓缩收率和截留率并观察超滤过程的膜通量及其变化。结果 植酸酶的浓缩倍数为６．５３倍,浓缩收率为９９．６９％,截留率为９９．９３％,系统可以在植酸酶的工艺条件下连续浓缩〉１０ｈ,且经过简单清洗后,膜通量基本恢复。结论 用ＰＵ－２０Ｋ－ＰＳ管式超滤膜系统缩植酸酶发醇液在技术上可行。     

羟丙基甲基纤维素（HPMC）在盐酸洛美沙星片生产中的应用

目的：考查羟丙基甲基纤维素合剂对盐酸洛美沙星片溶出度的影响,选择出最佳粘合剂浓度。方法：实验选用5种浓度的HPMC制备盐酸洛美沙星片,用RC－2型药物溶出仪测定咄度,从中选出最佳粘合剂浓度。并采用两种处方、三种粘合剂制片,。进行溶出度及片面比较。结果：用5％HPMC作粘合剂不仅可改善片剂出度,而且片面明显优于加有吐温－80者。结论：羟丙基甲基纤维素可改善片剂溶出度,效果明显。     

大鼠内关注射肾上腺素对血流动力学与血药浓度的影响

目的：研究大鼠内关穴注射肾上腺素对血流动力学参数和血浆肾上腺素含量的影响。方法：采用直接插管、微机测取血流动力学指标法以及高效液相色谱法测定血浆肾上纱含量。结果：内关穴注射肾上腺素后,血压迅速上升,反映心肌收缩性能的ｄｐ／ｄｔｍａｘ,Ｖｐｍ和Ｖｍａｘ等指标增大,药理效应与静脉给药相似,而血浆肾上腺素浓度明显低于静脉给药组（Ｐ〈０．０１）。结论：内关穴可能存在接受与传递肾上腺素信息的中介物质和途径。