Drug-Biomacromolecule Interaction XII: Comparative binding study of sulfaethidole to bovine serum albumin by equilibrium dialysis,fluorescence probe technique,uv difference spectrophotometry and circular dichroism

Binding of sulfaethidole to bovine serum albumin was studied by equilibrium dialysis, fluorescence probe technique, uv difference spectrophotometry and circular dichroism. Equilibrium dialysis method enabled us to estimate the total number of drug binding sites of albumin molecule. For sulfaethidole, albumin had 6 primary and 40 secondary binding sites. The primary and secondary binding constants were 0.9×10⁵ M⁻¹ and 0.2×10⁶ M⁻¹, respectively. 1-Anilino-8-naphthalenesulfonate (ANS) and 2-(4′-hydroxylbenzeneazo)-benzoic acid (HBAB) were used as the fluorescence probe and the uv spectrophotometric probe, respectively. In fluorescence probe technique, results indicated that the number of higher affinity drug binding site of albumin was 1 and the number of lower affinity drug binding sites of albumin was 3, and the primary and secondary drug binding constants for bovine serum albumin were 2.15×10⁵ M⁻¹ and 1.04×10⁵ M⁻¹, respectively. In uv difference spectrophotometry, binding sites were 3 and binding constant was 1.88×10⁵ M⁻¹. The above results suggest that several different methods should be used in ompensation for insufficient information about drug binding to albumin molecule given by only one method.     

Impedance study of the electrochemical reduction of adrenochrome on glassy carbon

The electrochemical reduction of adrenochrome on a glassy carbon electrode was investigated by ac impedance in a constant ionic strength McIlvaine buffer solution. When the frequency was lower than 60 kHz, —Z″ against Z′ showed straight lines whose inclined angles with the real axis were within the range 71–76° in the diagrams of the complex impedance plane obtained at different do potentials. In the corresponding admittance diagrams, distorted semicircles appeared. The electrode reaction involves adsorption of electroactive species and the effect of concentration polarization cannot be neglected. Based upon the admittance model of the equivalent circuit, the optimal estimated values of some model parameters were obtained by using a Gauss-Newton algorithm and non-linear curve fitting. The characteristics of the electrode process are also discussed.     

螯合吸附分离功能纤维的研究进展

螯合纤堆是一类能与金属离子形成多配位络合物的纤堆状吸附功能材料，是近年来发展起来的一种新型离子交换纤堆，具有吸附选择性高、易洗脱、容易再生等优点。综述了近年来螯合纤堆的制备方法及种类，对其螯合机理进行了探讨，概括了该纤堆的应用范围并指出了其应用前景。     

Amplified fragment length polymorphism analysis of the VNTR locus D1S80 in central Spain

Summary The polymorphism of the D1S80 locus has been analyzed in a population sample of 203 unrelated individuals living in Madrid (central Spain) by PCR and subsequent semi-dry discontinuous polyacrylamide gel electrophoresis (Tris-chloride/Tris-glycine buffer system) followed by silver staining, The electrophoretic system described in this study offers high resolution in the separation of the different D1S80 alleles allowing the detection of microvariability around the allele T22 in the spanish population. Twenty different alleles containing 17–40 repeats of the basic 16bp unit were distinguished. The alleles T18 and T24 were found to be relatively common in Spain, as in other populations:, with frequencies of 0.224 and 0.372, respectively. No evidence of significant deviations from Hardy-Weinberg equilibrium was found in these preliminary population data.     

新型阳离子(苯乙烯—丙烯酰胺)共聚物的研究 Ⅱ.阳离子(苯乙烯——丙烯酰胺)共聚物与染料的相互作用

以P(St-Am·MG)对染料活性艳红(X-3B)溶液进行絮凝试验,考察了高聚物剂量及外加盐对絮凝效果的影响,并与无疏水基团的阳离子聚丙烯酰胺PAm·MG的絮凝能力进行了比较。发现絮凝体系无外加盐时,高聚物与染料的作用主要是通过静电力;有外加盐时,高聚物的电荷受到屏蔽,高分子链卷曲,PAm·MG的絮凝效果受到较大影响。而P(St-Am·MG)与X-3B之间存在疏水相互作用,受影响较小,此时P(St-Am·MG)的絮凝性能优于PAm·MG。用平衡渗析法研究了不同温度时甲醇和脲存在下P(St-Am·MG)与X-3B相互作用的热力学。证明了它们之间确实存在疏水相互作用。     

细胞内抗原免疫金银染色技术的改进

为解决细胞内抗原应用免疫金银法染色时背景过重的问题,建立了甘氨酸二次阻断的处理方法,效果较好。     

Modelling HA protein-mediated interaction between an influenza virus and a healthy cell: pre-fusion membrane deformation.

We present a mathematical model for pre-fusion interaction between an influenza virus and a healthy cell. Our model describes the role played by hemagglutinin (HA) protein clusters in bringing the viral membrane into close contact with the host cell membrane as a first step of the fusion process between the two membranes. The viral membrane is modelled as a lipid bilayer with bending rigidity. Using the calculus of variations, we compute the deformation of the viral membrane under the influence of HA protein clusters. Our numerical results support the hypothesis of dimple formation in the fusion site proposed in the literature. The asymmetric nature of the protein molecules due to various reasons such as tilting is the primary cause for the dimple formation. We discuss the effects of spontaneous curvature, the protein cluster radius, fusion-site size and the bending moment exerted by the protein cluster. We also examine the effects of membrane tension and the presence of a host cell on the dimple shape. Our results support previous experimental observations.     

Myocardial oxygen extraction and oxygen-hemoglobin equilibrium curve during moderate exercise

Summary Conditions of oxygen extraction by the myocardium have been studied in 12 subjects (44±9 years old) with pure mitral stenosis without clinical, metabolic or electrical sign of coronary insufficiency.Oxygen-hemoglobin equilibrium curves (OHEC) have been determined on arterial, mixed venous and coronary sinus blood, at rest and during a moderate (60 W, 10 min) exercise performed on a bicycle ergometer in supine position. Physiological values, at rest and during exercise, of the following functional parameters of the OHEC were determined in the in-vivo conditions of pH and P_CO2P₅₀, n_Hill, DS max = maximal value of OHEC slope (DS=S_O2/P_O2), P_{DS max}, S_{DS max}. The concentration of plasma electrolytes capable to modify one of these parameters was controlled in each blood sample.In coronary sinus blood, P₅₀ rises from 27.5±1.7 to 28.9±1.6 Torr during exercise (p<0.01). At rest, Hill's n in myocardial venous blood (2.67±0.09) is significantly higher than in arterial blood (2.61±0.08, p<0.01). A decrease in DS max (2.67±0.20 to 2.53±0.12%. Torr^–1; p<0.01) and an increase in P_{DS max} (20.9±1.9 to 22.6±2.1 Torr, p<0.01) are observed. At rest, the myocardial venous point (PcsO₂, ScsO₂) is not significantly distinct from the maximal slope point (P_{DS max}, S_{DS max}). After 1 min of exercise, a small gap appears which becomes significant at the end of the exercise (P_{DS max}-PcsO₂=0.2 Torr at rest, 2.7 Torr after exercise; S_{DS max}-ScsO₂=4.1% at rest, 7.9% after exercise). DS value at the myocardial venous point is only 2% at rest and 6% after exercise, lower than its maximal value.The gap between venous point and DS max point could constitute an error signal in the regulation loop of the coronary circulation. The existence of a physiological receptor, sensitive to instant variations in myocardial tissue P_O2 and able to maintain venous point near DS max point could be considered.     

硫酸酯化葡甘聚糖凝胶颗粒的微观形貌及其吸附行为研究

制备了硫酸酯化魔芋葡甘聚糖凝胶颗粒血液低密度脂蛋白吸附剂，扫描电镜观察产物呈交联网状多孔结构。体外静态吸附实验表明：在37℃振荡吸附2h后，对总胆固醇（TC）、低密度脂蛋白及超低密度脂蛋白胆固醇（LDL＋VLDL-C）、高密度脂蛋白胆固醇（HDL-C）的吸附率分别为52．68％、54．76％、27．78％。通过吸附动力学曲线和吸附等温线分析，吸附剂对LDL＋VLDL-C的作用包括类似分子筛的吸附和电荷间静电相互作用两种方式。     

类金刚石薄膜蛋白吸附与碳相成分关系的定量分析研究

运用灰色系统理论中的 T型关联度分析方法 ,对类金刚石 (DL C)薄膜、富石墨相 DL C薄膜和富金刚石相 DL C薄膜三种 DL C薄膜进行了碳相成分对其白蛋白 (HSA)、纤维蛋白原 (HFG)、免疫球蛋白 (Ig G)三种血浆蛋白吸附量影响的定量分析研究。合理地解释了三种材料蛋白吸附量随碳相成分变化的实验结果 ,并得出如下重要的分析结论 :(1)石墨和 C- H相对 HSA的吸附影响较大 ,随着二者的增加 ,HSA的吸附量下降 ;(2 )与 HFG吸附有较强关联的碳相成分是 DL C相和 C- O相 ,前者呈负相关 ,后者为正相关 ;(3)各碳相成分对 Ig G的吸附均有性质不尽相同的影响 ,但程度有限 ,且彼此间相差不大 ;(4 ) DL C碳相具有增强 HSA吸附、抑制 HFG、Ig G吸附的双重功效 ,其对 DL C薄膜血液相容性的影响远较其它碳相成分更为重要。