Drug-protein binding kinetics in patients with Type I diabetes

Summary Sera from 17 patients with Type I diabetes and 19 healthy volunteers have been examined to evaluate whether the kinetics of the binding of drugs to Site II of serum albumin is altered in diabetes. Stopped-flow measurements showed that the association velocity and the affinity constants of the fluorescent marker dansylsarcosine were significantly lower in diabetics (160 s^–1 and 2.0 × 10⁵ l·mol^–1) than in non-diabetics (196s^–1 and 4.0 × 10⁵ l·mol^–1). The dissociation velocity was not different [20.3 s^–1 vs. 19.4 s^–1]. Although patients with a reduced albumin concentration were excluded the diabetics had significantly lower concentrations than the healthy volunteers. There was a significant correlation between decreased glycosylation of albumin and increased association velocity. The dissociation velocity constants were correlated with the molar concentration ratio of free fatty acids/human serum albumin. Thus, the extent of glycosylation and the amount of fatty acids bound per mole albumin can both affect the kinetics of drug binding to Site II. The lower affinity in patients with Type I diabetes is due to the increased in the glycoalbumin concentration.     

Influence of complement on sperm motility

Isolated sperm from normo-, oligo- and astheno-spermic men were incubated for 20 h in medium supplemented with 8% heat-inactivated or untreated human serum, and in medium with heated or untreated serum deficient in complement factor C3. Before and after incubation, sperm motility was assessed by means of a computer-assisted semen analyser. The results did not show significant differences between the motility of sperm incubated in heated or untreated serum. It is concluded that heating of homologous serum is not necessary for preserving sperm motility and in some cases may even be disadvantageous.     

Amadori糖化白蛋白对牛视网膜血管二酯酰甘油--蛋白激酶C级联的影响

目的 :探讨Amadori糖化血清白蛋白对牛视网膜血管二酯酰甘油 (DAG)———蛋白激酶C(PKC)信号级联的影响及d-α-生育酚的干预作用。方法 :体外制备的Amadori糖化的牛血清白蛋白 (AGSA)分别在生理浓度葡萄糖 (5 .5mmol/L)和高浓度葡萄糖 (2 0mmol/L)培养液中作用于新鲜牛视网膜血管。采用薄层层析和放射自显影法测定DAG含量和PKC活性 ;并检测d -α-生育酚预处理后DAG、PKC改变。结果 :在生理葡萄糖浓度下 ,牛视网膜血管暴露于AGSA2 4h或 72h后细胞内DAG含量、PKC活性均较对照组显著增加 ,当AGSA和高葡萄糖同时作用于牛视网膜血管时 ,DAG -PKC级联显著激活 ,分别为正常葡萄糖组的 3.4 7倍和 4 .5 4倍 ;在正常血清培养液中 ,与 5 .5mmol/L的葡萄糖相比 ,2 0mmol/L高糖在 2 4h时并不刺激DAG含量增加 (P >0 .0 5 ) ,而 72h时则较对照组增加 4 5 % ,PKC活性较对照增加 5 6 % ,而d -α -生育酚可逆转上述生化改变。结论 :Amadori糖化血清白蛋白可在生理葡萄糖浓度下刺激DAG -PKC途径活化 ,从而影响血管一系列生理功能 ,而d -α-生育酚对血管生化改变有保护作用。     

人血清中全氟辛烷磺酰基化合物污染现状

目的 了解我国一般人群体内的全氟辛烷磺酰基化合物(PFOS)负荷水平。方法 采用液相色谱／质谱仪联机选择性监测离子法(m／z=499)，测定被调查血清中PFOS浓度。结果 男女血清中PFOS浓度几何均数分别为40．73和45．46μg／L，血清PFOS浓度与年龄无关。结论 我国一般人群体内也存在PFOS污染物，而且血清PFOS浓度高于美国人和日本人水平。     

深低温对吸入麻醉药的MAC,心脏麻醉指数和心肌稳定性的影响

目的:研究深低温对吸入麻醉药MAC、心脏麻醉指数和心肌稳定性的影响。方法:新西兰白兔40只,随机分为氟烷、安氟醚、异氟醚和七氟醚组。采用夹尾试验法测定常温下(38℃±0.5℃)的最低肺泡有效浓度(MAC)。行体表降温后测定深低温下(23℃±0.5 ℃)的MAC。维持深低温增加吸入性麻醉药的浓度,同时用50Hz、25V电压胸外电击心脏。记录出现室颤或室性心律失常时的肺泡呼气末吸入麻醉药浓度。结果:从38℃到23℃兔体温每降低1℃,MAC下降值为:氟烷5.1％、安氟醚3.6％、异氟醚4.4％、七氟醚4.3％;氟烷、安氟醚、异氟醚和七氟醚心脏麻醉指数分别为4.4、3.18、6.25和4.6,异氟醚明显高于其它麻醉药;麻醉药浓度8MAC以内安氟醚和氟烷发生室颤的机率(100％)明显高于七氟醚和异氟醚(40％)。结论:异氟醚是深低温麻醉的最佳选择用药,而安氟醚则不宜用于低温麻醉。     

主动吸入药物烟对大鼠一氧化氮的影响

目的　探讨主动吸入药物烟对大鼠NO的影响。方法　制备大鼠主动吸烟模型 ,采用硝酸还原酶法测定各组大鼠血清、肺、心肌及脑组织的NO含量。结果　非药物烟组大鼠血清、肺、心肌及脑组织中NO含量明显低于非给烟对照组 ,药物烟高、中剂量组NO含量明显高于非药物烟组 ,接近非给烟对照组。结论　吸烟对大鼠血液、肺、心肌及脑组织有不同程度的损伤作用 ,使NO含量降低 ;药物烟具有一定的保护和防止NO含量降低的作用。     

高效液相色谱法测定头孢他啶血药浓度

目的建立测定头孢他啶血药浓度的方法。方法高效液相色谱法采用Kromasil C18色谱柱（250mm×4．6mm，5μm），以甲醇-磷酸二氢钾溶液（15：85）为流动相，流速1．0ml／min，检测波长254nm。结果头孢他啶吼浆浓度在0．5～200．0mg·L^-1范围内线性笑系良好（r=0．9999）。低、中、高3个浓度的方法回收率为94．91％～105．95％，RSD〈12％；提取回收率为89．50％～92．94％，RSD〈5％。结论本方法简便、准确、精密度好，可用于临床药动学研究。     

可溶性白细胞介素-2受体与支气管哮喘

支气管哮喘是常见病和多发病，多种细胞因子参与了支气管哮喘的发病过程。发作期支气管哮喘患者血清可溶性白细胞介素—2受体(SIL—2R)水平明显增高。本文就这方面的进展作一综述。