冰片修饰的姜黄素阳离子脂质体的制备及其脑靶向作用研究

目的 制备冰片修饰的姜黄素阳离子脂质体（curcumin-loaded modifying borneol cationic liposomes，Cur-BCLPs），鼻腔给药后考察其在大鼠体内的药动学行为并对其脑组织分布进行研究。方法 采用乙醇注入法制备Cur-BCLPs；透射电镜观察阳离子脂质体的形态；激光粒度仪考察粒径；超速离心法测定其包封率及载药量；以姜黄素混悬液（curcumin suspension，Cur-Sol）和冰片-姜黄素混悬液（borneol curcumin suspension，BO-Cur-Sol）为对照组，考察大鼠鼻腔给药Cur-BCLPs的体内药动学过程，并测定其在大鼠脑组织的浓度，运用DAS 2.0软件拟合药动学参数。结果 阳离子脂质体外观呈圆形或类圆形，平均粒径为（105.99±2.40）nm，包封率和载药量分别为（81.95±1.03）%和（4.28±0.46）%；体内药动学结果显示，Cur-Sol、BO-Cur-Sol和Cur-BCLPs的半衰期（T_1/2）分别为（4.27±1.53）h，（3.98±0.24）h和（6.01±0.63）h，AUC_0→t分别为（224.38±21.95）μg·h·L^-1，（243.40±12.26）μg·h·L^-1和（562.28±24.30）μg·h·L^-1，清除率分别为（1.82±0.36）L·h^-1·kg^-1，（1.72±0.11）L·h^-1·kg^-1和（0.78±0.03）L·h^-1·kg^-1，滞留时间分别为（4.28±0.23）h，（4.41±0.15）h和（8.09±0.17）h。脑组织分布结果显示，Cur-Sol、BO-Cur-Sol和Cur-BCLPs的AUC_0→t分别为（29.82±1.10）μg·h·g^-1，（35.47±1.75）μg·h·g^-1和（54.06±3.90）μg·h·g^-1，清除率分别为（15.73±0.84）L·h^-1·kg^-1，（13.23±0.52）L·h^-1·kg^-1和（8.52±0.92）L·h^-1·kg^-1。结论 Cur-BCLPs经鼻腔给药后显著提高姜黄素体内和脑组织蓄积量并且延缓消除。     

单次和多次口服氯乙酰左卡尼汀片在健康人体的药动学研究

目的 采用LC-MS/MS测定人血浆中乙酰左卡尼汀的浓度并用于氯乙酰左卡尼汀片在健康受试者体内的药动学研究。方法 健康受试者单次给药0.5,1.0,1.5 g和多次给予0.5 g后,0~24 h采集血样。通过测定单次和多次给药后血浆中乙酰左卡尼汀的绝对浓度,计算其药动学参数。米屈肼为内标,经甲醇沉淀蛋白后进行LC-MS/MS分析。ESI离子源正离子模式监测,检测离子m/z 204.3→145.2（乙酰左卡尼汀）,m/z 147.2→58.2（米屈肼）;色谱柱为EC 250/4.6 NUCLEOSIL100-5CN,流动相为甲醇-10 mmol·L^-1乙酸铵溶液（含0.1%甲酸）（85：15）。结果 乙酰左卡尼汀在20~3 000 μg·L^-1内线性良好（r=0.999 1）,最低定量限为20 μg·L^-1。批内、批间精密度及基质效应RSD均<15%。单次给药3个剂量组（0.5,1.0,1.5 g）的主要药动学参数为：AUC_0-t为（4 181.77±2 473.24）μg·h·L^-1、（6 099.54±1 939.41）μg·h·L^-1和（8 064.71±3 575.99）μg·h·L^-1,C_max为（611.42±270.76）μg·L^-1,（830.92±233.19）μg·L^-1和（1 004.67±414.95）μg·L^-1,t_1/2z为（4.50±2.93）h、（6.25±3.65）h和（5.76±3.94）h;多次给药后主要的药动学参数：AUC_0-t为（13 728.82±6 493.04）μg·h·L^-1,C_max为（1 129.00±374.05）μg·L^-1,t_1/2z为（8.57±4.42）h。结论 本方法准确、灵敏、专属性强,适用于人体内乙酰左卡尼汀药动学研究。单次和多次给予氯乙酰左卡尼汀片后药动学参数有明显差异,性别间无差异,健康受试者对药物的耐受性良好。     

氟伐他汀钠缓释片的制备及其Beagle犬体内药动学研究

目的 制备氟伐他汀钠缓释片,进行体外释放特性以及Beagle犬体内药动学研究。方法 以羟丙甲纤维素为缓释材料制备氟伐他汀钠缓释片,测定其体外释放度和Beagle犬口服单剂量及多剂量后的血药浓度,推算药动学参数。结果 制备的氟伐他汀钠缓释片体外释放行为相似,口服单剂量和多剂量药动学参数C_max分别为（3 304.23±1 043.30）μg·L^-1和（3 760.86±754.77）μg·L^-1,T_1/2分别为（7.37±4.09）h和（6.04±2.63）h,AUC_（0-t）分别为（15 052.91±3 878.01）μg·L^-1和（15 374.91±2 712.20）μg·h·L^-1。结论 制备的氟伐他汀钠缓释片具有较明显的缓释效果,多次给药未出现明显的蓄积现象,表现出良好的安全性。     

活性氧/谷胱甘肽双重响应型紫杉醇前药纳米粒的制备与评价

目的 设计具有活性氧/谷胱甘肽双重响应的紫杉醇前药纳米粒(ProPTX-SS-NPs),为紫杉醇的应用提供新思路和新方法。方法 以粒径和PDI为指标,考察前药纳米粒的最佳制备方法和工艺;通过电镜观察前药纳米粒的形貌并对其粒径、电位、包封率、载药量等进行考察;考察纳米粒在活性氧和谷胱甘肽环境下的体外释放特性;通过细胞试验考察前药纳米粒的体外细胞毒性和细胞摄取情况。结果 采用最佳工艺制备的纳米粒粒径为(130.20±2.18) nm,分散系数为0.12±0.01,Zeta电位为(–8.45±0.01) mV,载药量为(10.27±1.36)%,包封率为(93.22±2.20)%。前药纳米粒具有良好的活性氧和谷胱甘肽响应特性,并且能够显著抑制MCF-7、HepG2和MDA-MB-231增殖。其对MDA-MB-231细胞的抑制作用最为显著,半数抑制浓度IC₅₀(0.71±0.11)μmol·L^-1,而PTX的IC₅₀为(22.38±3.27)μmol·L^-1。结论ProPTX-SS-NPs具有良好的肿瘤微环境响应性能,具备显著的抗肿瘤活性,是一种极具潜力和应用前景的抗肿瘤纳米系统。     

老年重症耐甲氧西林金黄色葡萄球菌感染患者替考拉宁的药动学研究和药效学评价

目的 探讨耐甲氧西林金黄色葡萄球菌（methicillin-resistant Staphylococcus aureus，MRSA）肺部感染老年患者替考拉宁的药动学差异与药效学评价。方法 研究纳入2018年9月—2019年8月诊断为MRSA肺部感染患者50例，治疗前下呼吸道痰液标本培养提示为MRSA感染并对替考拉宁敏感。所有患者予静脉输注替考拉宁，前3剂400 mg，每12 h给药1次，维持剂量400 mg每24 h给药1次。将达到稳态后第5次给药前测得C_min≤10 μg·mL^-1的患者维持剂量方案更改为600 mg qd。注射用替考拉宁400 mg或600 mg溶于100 mL 0.9%氯化钠注射液，给药时间为30 min，疗程为14~21 d。按规定时间采集静脉血2 mL，采用HPLC检测血药浓度，使用DAS 3.0软件处理，求出各例患者的药动学参数。将达稳态后第5次给药前测得C_min>10 μg·mL^-1的药动学参数设为A；对于C_min≤10 μg·mL^-1的患者，将维持剂量调整为600 mg qd，并将调整剂量后第5次给药前测得C_min>10 μg·mL^-1的药动学参数设为B。按照APACHE II评分和SOFA评分将患者分为重症和非重症2组。结合PK/PD原理，比较2组患者在C_min处于10~20 μg·mL^-1和20~30 μg·mL^-1以及AUC/MIC≥345和<345的临床治疗有效率、细菌清除率及不良反应发生情况。结果 替考拉宁药动学以二室模型描述最佳。负荷剂量相同时，维持剂量为400 mg的A组与维持剂量为600 mg的B组药动学参数比较如下：C_max[（32.28±15.16） mg·L^-1vs（65.73±28.96） mg·L^-1]，t_1/2[（86.24±10.61） h vs（70.51±11.78） h]，V_d[（2.73±1.32） L·kg^-1vs（2.58±1.02） L·kg^-1]，CL[（0.11±0.05） L·h^-1·kg^-1vs（0.13±0.06） L·h^-1·kg^-1]，AUC_（0~t）[（2 698.16±1 603.25） mg·h·L^-1vs（4 076.85±1 873.09） mg·h·L^-1]，AUC_（0~∞）[（4 509.33±2 786.54） mg·h·L^-1vs（7 193.58±4 109.81） mg·h·L^-1]，差异有统计学意义（P<0.05）。患者SOFA评分≤5和>5的临床有效率为65.71%和53.33%，细菌清除率分别为65.79%和47.37%。APACHEII评分≤15和>15的临床有效率分别为63.64%和58.82%，细菌清除率分别为63.16%和52.63%。结论 MRSA肺部感染老年患者替考拉宁的药动学存在较大差异，结合PK/PD原理，能够为个体化治疗提供科学的给药方案。     

PEG-PLA-α-细辛脑纳米粒经鼻腔、静脉给药后的药动学研究

目的 采用与静脉注射对比的方式,研究聚乙二醇-聚乳酸-α-细辛脑纳米粒（PEG-PLA-α-细辛脑纳米粒）鼻腔给药后在大鼠体内的药物动力学。方法 以大鼠为动物模型,采用血药动力学、脑药动力学及荧光标记法对比研究PEG-PLA-α-细辛脑纳米粒经鼻腔给药与静脉注射后药物/纳米粒在大鼠体内的分布情况。结果 PEG-PLA-α-细辛脑纳米粒静脉注射及鼻腔给药后血浆中的AUC_（0-∞）分别为（11032.4±1 827.1）ng·mL^-1·min及（5 992.9±717.5）ng·mL^-1·min,C_max分别为（421.9±100.2）ng·mL^-1及（171.7±26.3）ng·mL^-1,PEG-PLA-α-细辛脑纳米粒鼻腔给药后的绝对生物利用度F为54.3%。PEG-PLA-α-细辛脑纳米粒静脉注射后α-细辛脑在脑组织中的C_max与鼻腔给药后α-细辛脑在脑组织中的浓度C_max分别为（217.9±29.9）ng·mL^-1及（334.2±62.7）ng·mL^-1,PEG-PLA-α-细辛脑纳米粒静脉注射与鼻腔给药后的AUC_brain/AUC_plasma值分别为1.37和2.85,且两者具有统计学意义。PEG-PLA-α-细辛脑纳米粒鼻腔给药后的药物脑靶向效率及鼻-脑传递百分比分别为208.03%及52.01%。荧光标记法结果显示,PEG-PLA-α-细辛脑纳米粒鼻腔给药后脑靶向性比静脉注射后更强。结论 PEG-PLA-α-细辛脑纳米粒适合于鼻腔给药治疗脑部疾病。     

盐酸环丙沙星壳聚糖纳米粒原位凝胶的制备与评价

目的 制备盐酸环丙沙星壳聚糖纳米粒原位凝胶，并评价其抑菌及创面愈合效果。方法 采用复乳法制备盐酸环丙沙星壳聚糖纳米粒，采用2因素2水平全因子析因实验设计考察了壳聚糖相对分子质量（X₁）和壳聚糖质量浓度（X₂）对壳聚糖纳米粒的药物包封率（Y₁）、粒径分布（Y₂）、多分散系数（Y₃）和Zeta电位（Y₄）的影响；并以泊洛沙姆407作为凝胶基质制备盐酸环丙沙星壳聚糖纳米粒原位凝胶。通过抑菌圈实验比较盐酸环丙沙星乳膏和盐酸环丙沙星壳聚糖纳米粒原位凝胶对金黄色葡萄球菌和铜绿假单胞菌的抑菌活性；使用无菌活检穿刺针在大鼠背部造成直径为5 mm的皮肤全切除的圆形人工创面，并使用金黄色葡萄球菌和铜绿假单胞菌的培养基感染24 h，建立大鼠创面模型，将模型大鼠随机分为模型组、盐酸环丙沙星乳膏组和盐酸环丙沙星壳聚糖纳米粒原位凝胶组，模型组大鼠创面未接受任何处理，给药组大鼠每2天给药1次，每次给药量均约为1 mg，观察并记录每组大鼠创面脱痂时间和愈合时间。结果 选择低相对分子质量壳聚糖、壳聚糖质量浓度为2.0 mg·mL^-1制备盐酸环丙沙星壳聚糖纳米粒，其中盐酸环丙沙星质量浓度为50.0 mg·mL^-1，其包封率为（85.3±0.9）%，平均粒径为（354.7±15.7）nm，PDI为0.357±0.014，Zeta电位为（22.2±0.5）mV，呈球状分布；盐酸环丙沙星壳聚糖纳米粒原位凝胶和盐酸环丙沙星乳膏对金黄色葡萄球菌的抑菌圈直径分别为（38.4±0.2）、（29.2±0.3）mm，对铜绿假单胞菌抗菌圈直径分别为（41.3±0.6）、（32.1±0.1）mm；大鼠创面给予盐酸环丙沙星壳聚糖纳米粒原位凝胶后，其脱痂时间和愈合时间均较模型组和盐酸环丙沙星乳膏组显著缩短（P<0.05）。结论 成功制备盐酸环丙沙星壳聚糖纳米粒原位凝胶，其可以抑制创面细菌繁殖、加速伤口愈合。     

丙戊酸钠和丙戊酸镁在大鼠体内的药动学研究

目的 研究丙戊酸钠和丙戊酸镁在大鼠体内的药动学特征,评价其优势丙戊酸盐,为临床合理用药提供参考。方法 SD大鼠随机分为2组,分别灌胃给予丙戊酸钠片和丙戊酸镁片。于不同时间点眼眶取血。采用HPLC测定血清中丙戊酸的血药浓度,计算2种丙戊酸盐在大鼠体内的药动学参数,并比较2种丙戊酸盐之间的差异。结果 HPLC测定丙戊酸血药浓度方法专属性好,血清丙戊酸浓度在10.00~110.00 μg·mL^-1内线性关系良好。精密度、稳定性和回收率均符合要求。丙戊酸钠和丙戊酸镁在大鼠体内的主要药动学参数：T_1/2分别为（14.02±3.86） h和（12.11±1.95） h;T_max分别为（3.67±0.58） h和（2.67±0.26） h;C_max分别为（67.10±10.87）μg·mL^-1和（75.67±12.94）μg·mL^-1;AUC_（0-t）分别为（969.86±72.08）μg·mL^-1·h和（1 093.56±48.69）μg·mL^-1·h;AUC_（0-∞）分别为（1 178.10±185.29）μg·mL^-1·h和（1 279.35±109.18）μg·mL^-1·h;MRT_0-t分别为（10.73±2.05） h和（13.06±3.24） h。V_d分别为（16.31±2.18） L和（23.47±2.19） L;CL分别为（0.056 3±0.009） L·h^-1和（0.051 1±0.004） L·h^-1。结论 与丙戊酸钠相比,丙戊酸镁在大鼠体内的药动学参数具有一定的优势,可能是一种更具有治疗优势的丙戊酸盐。     

柱前衍生-HPLC测定白消安在家兔体内的药动学参数

目的 建立测定家兔血清中白消安浓度和家兔体内药动学特征的柱前衍生化HPLC。方法 以1,5-戊二醇二甲磺酸酯为内标,二乙基二硫代氨基甲酸钠为衍生化试剂。流动相：甲醇-水（54∶46）,流速：0~20 min（1.0 mL·min^-1）,20~27 min（1.3 mL·min^-1）。柱温：30℃,检测波长：280 nm,进样量：25 μL。家兔分别以灌胃、静注的方式给予白消安,按本法测定血药浓度,DAS 3.0计算药动学参数。结果 白消安的血药浓度在0.1~3.4 mg·-L¹ 内线性关系良好（r=0.999 7）,日内、日间精密度以及样品稳定性符合中国药典2015年版的规定。低、中、高浓度的萃取回收率分别为90.0%,89.0%,91.5%。不同给药途径获得的药动学参数：单剂量口服t_1/2=（2.26±0.66）h,k=（0.33±0.12）·h^-1,k_a=（2.54±1.3）·h^-1,AUC_0–t=（1.95±0.18）h·mg·mL^-1;单剂量静脉注射t_1/2=（1.53±0.09）h,k=（0.45±0.03）·h^-1,AUC_0–∞=（4.38±0.26）h·mg·mL^-1。多剂量口服后C_ss=（0.48±0.03）mg·mL^-1,AUC_0–τ=（3.87±0.26）h·mg·mL^-1。结论 建立的柱前衍生-HPLC法适用于白消安血药浓度测定及药动学研究,不同给药途径的药动学参数为临床药动学研究提供了依据。     

UPLC-MS/MS快速测定大鼠血浆中盐酸美沙酮及其代谢产物含量

目的 建立超高效液相色谱-串联质谱（UPLC-MS/MS）测定大鼠血浆中盐酸美沙酮及其代谢产物乙二胺二甲基次磷酸（2-ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidine,EDDP）的含量。方法 以地西泮为内标,大鼠血浆用乙腈沉淀蛋白,运用UPLC-MS/MS检测大鼠灌胃盐酸美沙酮6 mg·kg^-1后血浆中美沙酮和EDDP的血药浓度,并对数据进行分析。结果 大鼠血浆中盐酸美沙酮和EDDP的定量限均为0.5 ng·mL^-1;线性相关系数r>0.999;日内精密度和日间精密度的RSD均<15%;绝对回收率均>85%,相对回收率在90%~110%之间;基质效应在92.80%~97.71%之间。主要药动学参数：美沙酮、EDDP在大鼠血浆中的消除半衰期（t_1/2）为（1.479±0.839）,（2.590±0.760）h;最高血药浓度（C_max）为（48.562±10.501）,（25.542±3.706）μg·L^-1;平均滞留时间（MRT_0-t）为（3.476±0.310）,（3.883±0.514）h;曲线下面积（AUC_0-t）为（204.036±61.145）,（86.031±15.287）μg·h·L^-1;清除率（CL）为（32.338±14.343）、（70.137±10.786）L·h^-1·kg^-1,各项药动学参数比较差异均有统计学意义。结论 该法专属性强、分离完全、快速灵敏,适用于大鼠血浆中盐酸美沙酮及其代谢产物EDDP的含量测定和药动学研究。     

Synthesis and evaluation of 2,6-piperidinedione derivatives as potentially novel compounds with analgesic and other CNS activities

New 2,6-piperidinediones 2_a–g and 4_a–d were prepared by initial condensation of aromatic aldehydes or cycloalkanones with cyanoacetamide to give α-cyanocinnamides l_a–g or cycloalkylidenes 3_a,b which underwent Michae1 addition with ethyl cyanoacetate or diethylmalonate. Compounds 4_a–d were alkylated by various alkyl halides to produce the N-alkylated 2,6-piperidinedione derivatives 5_a–m. Some new selected compounds 2_a–c,f, 4_a–d & 5_e,h,j were pharmacologically evaluated for potential anticonvulsant, sedative and analgesic activities. These compounds exhibited significant anticonvulsant and analgesic effects after a single I.P. administration 100 mg/kg b.wt. . On the other hand all the investigated compounds induced hypnotic activity and prolonged the phenobarbital sodium- induced sleep as compared with the control group and the most potent compound was found to be 2_f.     

NEURAMIDE STIMULATES ADRENOCORTICOTROPIN BUT NOT PROLACTIN RELEASE FROM RAT PITUITARY

Neuramide (NMD), a substance found in crude preparations of porcine stomach extract, is a viral inhibitor that also has putative immunostimulatory effects. The effects of NMD on stress-hormone (ACTH and prolactin—PRL) release were assessed inin vivoandin vitrostudies. In the former, blood levels of corticosterone and PRL were measured in NMD-treated male rats.In vitroexperiments were performed to evaluate the effects of NMD and three of its fractions (obtained with high performance liquid chromatography) on ACTH and PRL release from perfused rat pituitary slices. NMD increased plasma corticosterone levelsin vivoand produced dose-dependent increases inin vitropituitary release of ACTH. No effects on PRL secretion were observedin vivoorin vitro. The stimulatory effects on ACTH release were caused by the NMD fraction with a molecular weight of >5000<10000Da.     

EFFECT OF POLICOSANOL SUCCESSIVE DOSE INCREASES ON PLATELET AGGREGATION IN HEALTHY VOLUNTEERS

Policosanol is a cholesterol-lowering drug with hypocholesterolemic effects demonstrated in experimental models, healthy volunteers and type II hypercholesterolemic patients. In addition, antiplatelet effects of policosanol have been shown in experimental models and healthy volunteers. The effect of successively increasing doses of policosanol on platelet aggregation was investigated in a randomized, placebo-controlled, double-blind study conducted in 37 healthy volunteers. The volunteers were on a placebo-baseline period (two tablets per day) for 7 days and thereafter they received randomly, under double-blind conditions, placebo or policosanol (10mgday⁻¹) for 7 days. After this period dosage was doubled to 20mgday⁻¹for the next 7 days and then again doubled to 40mgday⁻¹, while the control group received placebo tablets all the time. Platelet aggregation as well as coagulation time was measured at baseline and after each dosing step. Results showed that antiplatelet effects of policosanol were successfully enhanced throughout the study, thus suggesting a dose-dependent relationship. No significant effect was reached during the first dosing period, but significant reductions of epinephrine and ADP-induced platelet aggregation were observed after the second one. Finally, a significant inhibition of platelet aggregation induced by all the agonists was observed at the last dosing step. Coagulation time remained unchanged during the trial.     

鼻渊净胶囊的HPLC指纹图谱研究

目的 建立鼻渊净胶囊的高效液相色谱（HPLC）指纹图谱。方法 采用Agilent SB-C₁₈（4.6 mm×250 mm,5 μm）色谱柱,乙腈-水为流动相、以1.0 ml/min流速行梯度洗脱,检测波长210 nm,柱温30 ℃,洗脱时间为80 min。采用中药色谱指纹图谱相似度评价系统（2004A版）对检测出色谱进行指纹图谱相似度评价。结果 建立了鼻渊净胶囊的HPLC指纹图谱,确定了20个共有峰,15个峰归属到各药材,其中5个峰确认了化学成分;10批样品的指纹图谱的整体相似度与对照图谱比较,均在90%以上。结论 所建立的鼻渊净胶囊指纹图谱有助于从整体上控制该制剂的质量。     

INDIRECT PARASYMPATHOMIMETIC ACTIVITY OF THE CLASS III ANTIARRHYTHMIC SUBSTANCE / -SOTALOLIN VITRO: REVERSIBLE INHIBITION OF CHOLINESTERASE ISOENZYMES FROM BLOOD AND THE HUMAN CENTRAL NERVOUS SYSTEM

Inhibitory effects of the class III antiarrhythmic compound / -sotalol on acetylcholinesterase (AChE; EC 3.1.1.7) isoenzymes of both erythrocytes and the human caudate nucleus and on serum cholinesterase (ChE; EC 3.1.1.8) were studiedin vitrousing a spectrophotometric kinetic assay with acetylthiocholine (ASCh) as substrate. Sotalol concentrations in the assays varied from 0.32 to 3.2m . All isoenzymes studied were inhibited by / -sotalol in a reversible and concentration-dependent manner. Double reciprocal plots of the reaction velocity against varying ASCh concentrations revealed that / -sotalol reduced substrate affinity (apparent Michaelis constant, KM, increased) of serum ChE, but did not change the enzyme's maximal rate of ASCh hydrolysis (V_max). Thus, / -sotalol inhibition of serum ChE was of the competitive type (rate constant for reversible competitive inhibition: K_i=0.51m ). In contrast, / sotalol reduced the maximal reaction velocity of the AChE isoenzyme from the central nervous system (caudate nucleus), but had no influence on substrate affinity of the enzyme (K_Mwith ASCh unchanged) indicating purely non-competitive inhibition kinetics (rate constant of reversible non-competitive inhibition: K_i′=0.44m ). / -sotalol inhibition of erythrocyte AChE was of mixed competitive/non-competitive type (K_i=0.31m , K_i′=0.49m ). Non-competitive / -sotalol inhibition of caudate nucleus AChE and the non-competitive component of erythrocyte AChE inhibition cannot be overcome by increased concentrations of the cholinergic transmitter acetylcholine (ACh). Peak / -sotalol plasma levels as described in the literature for both humans (15μ ) and experimental animals (dogs: 18μ ; rats: 260μ ) as well as maximal myocardial concentrations of the substance (dogs: 46μ ; rats: 478μ ) are in the range of about 2% to 100% of the sotalol inhibition rate constants determined in the present paper for cholinesterase isoenzymesin vitro. Thus, / -sotalol inhibition of ACh hydrolysisin vivomay contribute to both the well known antiarrhythmic potential and proarrhythmic side effects of the compound.     

Investigation of the prevalence of tetQ, tetX and tetX1 genes in Bacteroides strains with elevated tigecycline minimum inhibitory concentrations

In this study, the antibiotic susceptibilities to tigecycline and tetracycline of 35 selected Bacteroides fragilis group strains were determined by Etest, and the presence of tetQ, tetX, tetX1 and ermF genes was investigated by polymerase chain reaction (PCR). tetQ was detected in all 12 B. fragilis group isolates (100%) exhibiting elevated tigecycline minimum inhibitory concentrations (MICs) (≥8 μg/mL) as well as the 8 strains (100%) with a tigecycline MIC of 4 μg/mL, whilst tetX and tetX1 were present in 15% and 75% of these strains, respectively. All of these strains were fully resistant to tetracycline (MIC ≥ 16 μg/mL). On the other hand, amongst the group of strains with tigecycline MICs < 4 μg/mL (15 isolates), tetQ, tetX and tetX1 were found less frequently (73.3%, 13.3% and 46.7%, respectively). All but two strains harbouring the tetQ gene in this group were non-susceptible to tetracycline, with a MIC > 4 μg/mL. These data suggest that in most cases tigecycline overcomes the tetracycline resistance mechanisms frequently observed in Bacteroides strains. However, the presence of tetX and tetX1 genes in some of the strains exhibiting elevated MICs for tigecycline draws attention to the possible development and spread of resistance to this antibiotic agent amongst Bacteroides strains. The common occurrence of ermF, tetX, tetX1 and tetQ genes together predicted the presence of the CTnDOT-like Bacteroides conjugative transposon in this collection of Bacteroides strains.     

AMELIORIATION OF CHEMICALLY-INDUCED HEPATOCYTE INJURY BY CYCLOSPORINE A

Cyclosporine A, beside its current applications, possesses potential hepatoprotective effects. This study was directed to investigate the effect of Cyclosporine A pretreatment on hepatic injury due to carbon tetrachloride (CCl₄) and -galactosamine. Rats were injected by two successive doses of Cyclosporine A (5mgkg⁻¹day⁻¹). Six hours after the second dose, 1mlkg⁻¹of CCl₄was administered i.p. Effects associated with Cyclosporine A pretreatment were examined by using isolated hepatocytes and hepatocytes that were immobilized and continuously perfused. -Galactosamine (5m ) was added directly to the perfusion medium. After isolation, hepatocytes were examined histologically by light and electron microscopy, immobilized and perfused for further metabolic functional activity evaluation. Cyclosporine A pretreatmentin vivoproduced hepatoameliorative effects of various degrees which were statistically significant as manifested by: (1) an increased trypan blue exclusion after CCl₄; (2) an improved ureagenesis after CCl₄; (3) a reduction in the lipid droplets accumulation in the cytoplasm produced by CCl₄administration; (4) well preserved cytoplasmic organelles as mitochondria, endoplasmic reticulum ER, nuclear chromatin structures that were altered by CCl₄; and (5) an increased hepatocytes survival in the agarose gel matrix, reduction of LD leakage and improvement of ureagenesis after -galactosamine addition to the perfusion medium. The beneficial effect of Cyclosporine A pretreatment in modifying hepatotoxicity of chemical insults merits further studies.     

喙果黑面神化学成分研究

目的研究大戟科植物喙果黑面神(Breynia rostrata Merr.)的化学成分。方法利用硅胶、凝胶等色谱技术分离纯化化学成分,根据化合物的理化性质和光谱数据进行结构鉴定。结果从喙果黑面神的正丁醇萃取部分分离得到4个化合物,分别鉴定为6-O-甲基丙酰基-α-D-吡喃葡糖(6-O-methylpropanoyl-α-D-glucopyranose,1);4″-苯酚基-6-O-甲基丙酰基-β-D-吡喃葡糖苷(4″-phenolic-6-O-methylpropanoyl-β-D-glucopyranoside,2);1-O-没食子酰基-β-D-吡喃葡糖苷(1-O-galloyl-β-D-glucopyranoside,3);熊果苷(arbutin,4)。结论化合物1和2为新化合物,3和4均为首次从该种植物分离得到。     

EFFECTS OF 2-GUANIDINE-4-METHYLQUINAZOLINE ON GASTRIC ACID SECRETION IN RATS

In this study 2-guanidine-4-methylquinazoline (2-GMQ) appeared to decrease basal and stimulated gastric acid secretion, while structurally related compounds as dimethyl- biguanide, cyanoguanidine and 2-cyanoamino-4-methylpyrymidine did not. Thus, there is an antisecretory effect when the biguanide group is associated with a lipophilic structure. The antisecretive effects exerted by 2-GMQ are associated with anti H₂-histamine activity.The anti H₂-histamine nature of the effects of 2-GMQ was confirmed by the capacity of this compound of depressing the chronotropic activity of the isolated guinea pig auricle increased by histamine, as well as relaxant activity in rat uterus contracted by histamine, since both preparations are rich in H₂-histamine receptors.     

Effect of bay K 8644, a calcium channel agonist,on dog cardiac muscarinic receptors

To investigate further whether the effects of the dihydropyridine (DHP) drugs on calcium channels are related to those of these drugs on muscarinic receptors, the binding characteristics of the DHP calcium channel agonist, Bay K 8644, on muscarinic receptors and calcium channels were compared to those of the DHP calcium channel antagonists, nicardipine and nimodipine in the dog cardiac sarcolemma. Bay K 8644, nicardipine and nimodipine inhibited the specific [³H]QNB binding with K _i values of 16.7μM, 3.5μM and 15.5μM respectively. Saturation data of [³H]QNB binding in the presence of these DHP drugs showed this inhibition to be competitive. Bay K 8644, like nicardipine and nimodipine, blocked the binding of [³H]nitrendipine to the high affinity DHP binding sites, but atropine did not, indicating that the muscarinic receptors and the DHP binding sites on calcium channels are distinct. The K _i value of Bay K 8644 for the DHP binding sites was 4 nM. Nicardipine and nimodipine (K _i :0.1–0.2 nM) were at least 20 times more potent than Bay K 8644 in inhibiting [³H]nitrendipine binding. Thus, the muscarinic receptors were about 4000 times less sensitive than these high affinity DHP binding sites to Bay K 8644. These results suggest that the DHP calcium agonist Bay K 8644 binds directly to the muscarinic receptors but its interaction with the muscarinic receptors is not related to its binding to the DHP binding sites on calcium channels.