抗氧化活性藻蓝色素与牛血清白蛋白的相互作用

目的:进一步验证藻蓝色素(phycocyanobilin,PCB)的抗氧化作用,并研究藻蓝色素与牛血清白蛋白(bovine serum albu-min,BSA)之间的相互结合反应。方法:通过1,1-二苯基-2-苦基肼(1,1-diphenyl-2-picrylhydrazyl,DPPH)清除法验证PCB的抗氧化作用。用荧光光谱法、分光光度法研究了PCB与BSA的相互结合反应。结果:PCB对DPPH自由基的清除作用呈现一定的量效关系。随着PCB浓度的增加,BSA的荧光强度有规律地降低且呈良好的线性关系。结论:抗氧化活性PCB能够有效地淬灭BSA的内源荧光,该猝灭作用属于静态荧光猝灭作用,反应的结合常数K=1.22×106L.mol-1,结合位点数n=1.14,与PCB的结合基本不会引起BSA的构象变化。     

荧光猝灭法快速测定芦荟大黄素血浆蛋白结合率的研究

目的:建立荧光猝灭法快速测定芦荟大黄素血浆蛋白结合率的理论和实验方法学。方法:在模拟人体生理条件下,以牛血清白蛋白(BSA)为荧光剂,芦荟大黄素为荧光猝灭剂,研究激发波长280nm下的荧光光谱。结果:芦荟大黄素和BSA的荧光猝灭是静态猝灭过程,其结合常数K30℃=6.024×104 L.mol-1和K37℃=5.104×104 L.mol-1;结合分子数n30℃=0.9776和n37℃=1.0548;相互作用力主要是静电作用;同时建立了预测血浆蛋白结合率的理论模型,并根据实验数据分析了芦荟大黄素浓度与BSA浓度动态变化时药物血浆蛋白结合率的全程规律。结论:不同蛋白质浓度与药物浓度条件下血浆蛋白结合率处于动态变化中,血浆蛋白结合率随药物浓度的增大而减少。     

荧光光谱法研究灯盏花素与牛血清白蛋白相互作用

目的采用荧光光谱法研究灯盏花素与牛血清白蛋白(BSA)在生理条件下(pH 7.4)的相互作用机制。方法固定BSA浓度,依次加入不同浓度的灯盏花素溶液,在激发波长为280 nm下,290~500 nm的波长范围内进行荧光猝灭光谱、同步荧光光谱扫描。结果灯盏花素对BSA的荧光猝灭类型是静态猝灭;在温度288 K和310 K时,二者的结合常数KA分别为8.295×105和3.302×105L.mol 1;二者的结合位点数n分别为1.239 3和1.177 0。由热力学参数焓变(H=31.080kJ.mol 1)小于零和熵变(S=5.392 J.mol 1.K 1)大于零,确定灯盏花素与BSA之间的作用力类型为静电作用力;生成自由能变(G)为负值,表明灯盏花素与BSA的作用过程是一个自发过程。此外,应用同步荧光光谱考察了灯盏花素对BSA构象的影响。结论经过荧光光谱分析,可以确定灯盏花素与白蛋白的作用机制,为其开发成治疗心血管疾病新药提供理论依据。     

HPLC-FIA法检测糖基化终末产物方法的建立

目的:建立糖基化终末产物(advanced glycation end products,AGEs)的一种检测方法。方法:利用高效液相色谱议(high performance liquid chromatography,HPLC)构建流动注射分析系统,检测体外制备的AGEs。荧光检测的激发波长和发射波长(Ex／Em)为370／440 nm。结果:Ex／Em为370／440 nm时,在原反应液的0．1～0．000 1浓度范围内仍有良好的线性,Y=67 979．98X+4．38,r=0．999 99;平均回收率98．5％,RSD= 3．4％。结论:流动注射分析(flow injection assay,FIA)是较可靠的检测AGEs水平的新方法。     

高效液相色谱荧光法测定脑脊液中丙泊酚浓度

目的建立高效液相色谱荧光检测法测定脑脊液中丙泊酚(异丙酚)浓度的方法.方法采用Hypersil ODS-C18柱为分析柱;甲醇-水-β-环糊精(68:32:0.01)为流动相,流速为1.0mL/min;激发波长为276nm,发射波长为310nm.结果异丙酚与脑脊液中其它成分分离良好,平均回收率为104.98%,日内、日间RSD均小于15%;脑脊液中异丙酚浓度在10～320ng/mL范围内线性关系良好,r=0.9992.结论该法操作简便、结果可靠,适用于脑脊液中异丙酚浓度的测定.     

荧光光谱法分析盐酸哌唑嗪与牛血清白蛋白的结合作用

目的研究不同温度下盐酸哌唑嗪与牛血清白蛋白(BSA)间的相互作用及其作用机制。方法荧光光谱法。结果荧光光谱法测定盐酸哌唑嗪与BSA在25℃和37℃反应的结合常数K均是2.0×104L.mol-1,结合位点数n分别为1.19,1.14,热力学参数为(37℃)ΔH=0,ΔG=-25.52kJ.mol-1,ΔS=0.082kJ.mol-1.K-1,盐酸哌唑嗪的加入影响了BSA的构象;依据Frster非辐射能量转移机制,得到盐酸哌唑嗪与BSA之间的结合距离和能量转移效率分别为r=4.69nm,E=0.078。结论盐酸哌唑嗪与BSA在实验浓度范围内形成了具有一定结构的复合物,且它们之间的作用力以静电作用力为主。     

HPLC法测定丝裂霉素C聚氰基丙烯酸正丁酯纳米粒中丝裂霉素C的含量

目的:建立高效液相色谱法测定丝裂霉素 C 聚氰基丙烯酸正丁酯纳米粒(MMC-PBCA-NP)中药物含量。方法:采用C_(18)柱(4.6 mm×150 mm,5 μm),以混合磷酸盐缓冲液-乙腈(85:15)为流动相,流速为1 mL·min~(-1),紫外检测器,检测波长为365 nm。结果:丝裂霉素 C(MMC)浓度在5～250 μg·mL~(-1)范围内与峰面积呈良好的线性关系,r=0.9998;平均回收率(n=6)为98.15%。结论:本法专属性强,操作简便,结果准确。适用于 MMC-PBCA-NP 的质量控制。     

三维荧光光谱结合交替三线性分解算法测定徐长卿药材中丹皮酚的含量

目的:采用三维荧光光谱结合交替三线性分解(ATLD)算法测定徐长卿药材中丹皮酚的含量。方法:构建三线性模型,利用最小二乘原理进行ATLD,采用核一致诊断法对体系的组分数进行拟合,采用数学校正法校正内滤光效应。三维荧光光谱扫描条件:激发波长范围为250~400 nm,发射波长范围为410~600 nm,波长间隔为5 nm,狭缝宽度为5.0/5.0 nm,扫描速度为1 200nm/min;测定吸收光谱条件:扫描波长范围为250~600 nm,扫描速度为600 nm/min;以Al(Ⅲ)作敏化剂增强丹皮酚的荧光强度。以高效液相色谱法(HPLC)测定药材样品中丹皮酚含量作为验证。结果:丹皮酚检测质量浓度线性范围为0.132~1.188μg/m L(r=0.999 9);精密度、稳定性、重复性试验的RSD<3.0%;加样回收率为100.1%~104.7%(RSD=2.39%,n=9);丹皮酚的解析光谱与其真实光谱几乎完全重合。HPLC测定结果与ATLD算法结果十分相近。结论:三维荧光光谱结合ATLD算法简便、快速、高效、准确,可用于复杂体系中特定组分的定性与定量分析。     

同步荧光光谱法研究牛蒡子苷-牛血清白蛋白体系的荧光增强效应

目的:研究牛蒡子苷与牛血清白蛋白(BSA)的相互作用机制.方法:采用紫外-可见吸收光谱法和同步荧光光谱法.结果:在△λ=15 nm时,牛蒡子苷对BSA的荧光具有规律性增强作用,最大发射波长蓝移,表明牛蒡子苷的加入影响了BSA中酪氨酸残基的微环境.用荧光效应增强方程计算它们在298 K、310 K和318 K温度下的结合常数分别为K1=7.899×104 L/mol、K2=5.962×104 L/mol和K3=3.903 × 104 L/mol,对应温度下的热力学参数△H=-26.874 kJ/mol,△S分别为3.601、4.737、3.395 J/(mol·K),△G分别为-27.940、-28.340、-27.951 kJ/mol.结论:牛血清白蛋白与牛蒡子苷分子间有较强的结合作用,且结合力以静电相互作用为主.     

荧光光谱法测定血清中维生素D_3含量

本文采用乙腈除蛋白的方法对血清进行了预处理。维生素D_3与荧光试剂(硫酸-乙醇溶液)的反应条件选择采用均匀设计。荧光分析条件为:激发波长(λ_(ex))427nm,荧光波长(λ_(em))490nm.维生素D_3浓度在0.1～10.0μg/ml范围内与荧光强度成线性关系(相关系数r=0.9981)。人血清中维生素D_3的平均回收率达97.5%以上。精密度也很好,日内变异系数为1.8%(n=6),日间变异系数为4.5%(n=8)以下。并用本法检出服药后血清中维生素D_3的浓度。     

Theoretical π-π* absorption and circular dichroic spectra of cyclic dipeptides

The dipole interaction model, treated by the partially dispersive normal mode method, is used to calculate circular dichroic spectra of cyclo(Gly-Gly), cyclo (Ala-Gly), cyclo(Ala-Ala), cyclo(Pro-Gly), cyclo(Pro-Ala), cyclo(Pro-Val), cyclo (Pro-D-Val), and cyclo(Pro-Pro) in the amide π-π* absorption band near 190 nm. Assuming a standard backbone geometry, spectra which are in fair to good agreement wth experiment are obtained for these molecules. The spectra are predicted to be sensitive to conformations of Pro and Val side chains. The effects of dipeptide ring folding on calculated CD spectra are mostly consistent with those found by other workers, except that it is found that a planar ring conformation of cyclo (Ala-Ala) and cyclo (Ala-Gly) gives predicted spectra comparable to experiment. The same model gives theoretical absorption spectra consistent with available experimental data.     

Effects of Nitro-L-Arginine on Blood Pressure and Cardiac Index in Anesthetized Rats: A Pharmacokinetic-Pharmacodynamic Analysis

Purpose. Nitric oxide synthase (NOS) inhibitors such as Nitro-L-arginine (L-NA) are being considered for the management of hypotension observed in septic shock. However, little information is available regarding the pharmacokinetic and pharmacodynamic properties of these agents. Our objective was to examine the relationships between L-NA plasma concentration and various hemodynamic effects such as cardiac index (CI), mean arterial pressure (MAP), and heart rate (HR) elicited by L-NA administration in rats. Methods. L-NA was infused at doses between 2.5 – 20 mg/kg/hr in anesthetized rats over one hour. Hemodynamic effects and plasma L-NA levels were determined. Results. Infusion of L-NA resulted in dose-dependent increases in MAP and systemic vascular resistance (SVR), decreases in CI, and minimal change in HR. The relationships between the hemodynamic effects and plasma L-NA levels were not monotonic, and hysteresis was observed. Using nonparametric analysis, the equilibration half-time (t_1/2,keo) between plasma L-NA and the hypothetical effect site was determined to be 51.5 ± 6.6 min, 42.4 ± 10.1 min, 43.4 ± 9.0 min for MAP, CI, and SVR, respectively (n = 14). The E_max and EC₅₀ values obtained were + 32.5 ± 8.4 and 2.6 ± 1.3 g/ml for MAP and –52.9 ± 15.6 and 3.7 ± 1.8 g/ml for CI, respectively. Conclusions. Although L-NA can bring about beneficial elevation of MAP, such effect is always accompanied by a stronger effect on CI depression. Dose escalation of L-NA may bring about detrimental negative inotropic effect and loss of therapeutic efficacy.     

洛美沙星体内外抗菌活性研究

洛美沙星对革兰氏阴性菌具有强的抑菌活力。对克氏肺炎杆菌的抗菌活性最强,MIC_(50)为0.12mg/L;对痢疾杆菌、产气杆菌、粘质沙雷氏菌、不动杆菌和枸椽酸杆菌的MIC_(50)分别为1和4mg/L。洛美沙星对肠细菌科细菌的活力比诺氟沙星和依诺沙星强2～16倍,明显地比丁胺卡那霉素、庆大霉素强。对金葡球菌MIC_(50)为1mg/L, MRSA对洛美沙星同样敏感。洛美沙星对表葡球菌、链球菌、粪链球菌及肺炎双球菌等的抗菌活性与地氟沙星相似,比诺氟沙星、依诺沙星、丁胺卡那霉素、庆大霉素和头孢三嗪分别强2～4倍。 洛美沙星对小鼠全身感染的疗效优于诺氟沙星。对大肠杆菌、克氏肺炎杆菌和绿脓杆菌感染小鼠iv的ED_(50)分别是0.74、0.13和3.45mg/kg, po的ED_(50)分别是0.94、1.46和6.20mg/kg。     

The pathogenesis of,and pharmacological treatment for,Canavan disease

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Protective role of exogenous α-lipoic acid (ALA) on hippocampal antioxidant status and memory function in rat pups exposed to sodium arsenite during the early post-natal period

The present work focussed on the effect of exogenous α-lipoic acid (ALA) administration on retention memory and oxidative stress markers in the hippocampus subsequent to early post-natal exposure of rat pups to sodium arsenite (NaAsO₂). Wistar rat pups were divided into the control groups receiving either no treatment (Ia) or distilled water by intraperitoneal route (i.p.) (Ib) and the experimental groups receiving either NaAsO₂ alone (1.5 and 2.0?mg/kg body wt.) (IIa, IIb) or NaAsO₂ (1.5 and 2.0?mg/kg body wt.) followed by ALA (70?mg/kg body wt.) (IIIa, IIIb) (i.p.) from post-natal day (PND) 4–15. The initial and retention transfer latency (ITL and RTL) was determined on PND 14 and 15 using elevated plus maze. The animals were sacrificed by cervical decapitation (PND 16) and the brains were obtained. The dissected out hippocampus was processed for estimation of oxidative stress markers, glutathione (GSH), and superoxide dismutase (SOD). NaAsO₂ exposure resulted in longer RTL in animal groups IIa and IIb, thereby suggestive of arsenic-induced impairment in retention memory. RTL was significantly shorter in animal groups (IIIa, IIIb) receiving ALA following NaAsO₂, thereby suggestive of improvement in retention memory. GSH and SOD levels were significantly decreased in animals receiving NaAsO₂ alone as against group Ib and administration of ALA following NaAsO₂ increased the levels of hippocampal GSH and SOD. These observations are suggestive of the role of exogenous ALA in ameliorating the adverse effects induced by NaAsO₂ exposure of rat pups on retention memory and oxidative stress markers.     

Dinoflagellate polyether within the yessotoxin, pectenotoxin and okadaic acid toxin groups: Characterization, analysis and human health implications

Diarrhetic Shellfish Poisoning (DSP) is a specific type of food poisoning, characterized by severe gastrointestinal illness due to the ingestion of filter feeding bivalves contaminated with a specific suite of toxins. It is known that the problem is worldwide and three chemically different groups of toxins have been historically associated with DSP syndrome: okadaic acid (OA) and dinophysistoxins (DTXs), pectenotoxins (PTXs) and yessotoxins (YTXs). PTXs and YTXs have been considered as DSP toxins because they can be detected with the bioassays used for the toxins of the okadaic acid group, but diarrhegenic effects have only been proven for OA and DTXs. Whereas, some PTXs causes liver necrosis and YTXs damages cardiac muscle after intraperitoneal injection into mice. On the other hand, azaspiracids (AZAs) have never been included in the DSP group, but they cause diarrhoea in humans. This review summarizes the origin, characterization, structure, activity, mechanism of action, clinical symptoms, method for analysis, potential risk, regulation and perspectives of DSP and associated toxins produced by marine dinoflagellates.     

大鼠溃疡性结肠炎模型的实验研究

目的对不同剂量的三硝基苯磺酸（ＴＮＢＳ）引起的大鼠溃疡性结肠炎（ＵＣ）模型进行观察和评价。方法采用一次性直肠注入大鼠ＴＮＢＳ（２５～１５０ｍｇ·ｋｇ－１）的３０％乙醇溶液，引起慢性炎症性肠疾病（ＩＢＤ），３ｗｋ后外死动物对各剂量下动物结肠的重量、髓过氧化物酶（ＭＰＯ）活性及组织形态学变化进行观察和评价。结果ＴＮＢＳ在１００～１５０ｍｇ·ｋｇ－１剂量下引起的ＵＣ肠壁明显增厚，炎症和溃疡至少维持７ｗｋ时间，ＭＰＯ活性值显著性升高，组织学检查发现粘膜及粘膜下层有大量中性粒细胞及淋巴细胞、巨噬细胞、纤维细胞浸润，肉芽组织及隐窝脓肿形成，５０ｍｇ·ｋｇ－１剂量时有一较轻度的损伤。２５ｍｇ·ｋｇ－１时对结肠的重量、ＭＰＯ活性及损伤指数都没有显著性改变（Ｐ＞０．０５）。结论用ＴＮＢＳ引起大鼠实验性ＵＣ，其溃疡和炎症维持一较长时间，这一病理特征为炎症性疾病防治药物的研究提供了条件；本模型的最佳剂量为１００ｍｇ·ｋｇ－１左右     

乙酰吉他霉素临床前药理学研究

乙酰吉他霉素对临床分离的革兰氏阳性球菌有较好的抑菌活力，其对金葡球菌、β－溶血性链球菌、表葡球菌的ＭＩＣ_（５０）分别为１、０．２２和４ｍｇ／Ｌ，对耐红霉素、青霉素的金葡球菌、表葡球菌半数以上较敏感，与吉他霉素相似，但其对革兰氏阴性菌无明显作用。乙酰吉他霉素对小鼠实验性细菌感染有明显保护作用。对金葡球菌、肺炎双球菌感染小鼠口服用药的ＥＤ_（５０）分别为７９．６和２５．１ｍｇ／ｋｇ。其疗效与吉他霉素、麦白霉素、乙酰螺旋霉素相似。乙酰吉他霉素小鼠１次口服的ＬＤ_（５０）＞１５ｇ／ｋｇ，与吉他霉素相比毒性无差异。     

Latent role of in vitro Pb exposure in blocking Aβ clearance and triggering epigenetic modifications

Both β-amyloid (Aβ) catabolism and epigenetic regulation play critical roles in the onset of neurodegeneration. The latter also contribute to Pb neurotoxicity. The present study explored the role of epigenetic modifiers and Aβ degradation enzymes in Pb-induced latent effects on Aβ overproduction in vitro. Our results indicated that in SH-SY5Y cells exposed to Pb, the expression of NEP and IDE remained declined during the recovery period, accompanied with abnormal increase of Aβ_1-42 and amyloid oligomer. A disruption of selective global post-translational histone modifiers including the decrease of H3K9ac and H4K12ac and the induction of H3K9me2 and H3K27me2 dose dependently was also showed in recovery cells. Moreover, histone deacetylase inhibitor VPA could attenuate latent Aβ accumulation and HDAC activity induced by Pb, which might be by regulating the expression of NEP and IDE epigenetically. Overall, our results suggest sustained reduction of NEP and IDE expression in response to Pb sensitizes recovery SH-SY5Y cells to Aβ accumulation; however, administration of VPA is demonstrated to be beneficial in modulating Aβ clearance.