Receptor-mediated toxicity of pahutoxin, a marine trunkfish surfactant.

Pahutoxin (PHN, choline chloride ester of 3-acetoxypalmitic acid) is a natural fish-killing (ichthyotoxic) agent derived from the defensive secretions of trunkfish. In spite of its obvious structural resemblance to synthetic cationic long-chain quaternary ammonium detergents, we show that PHN's action does not rely on its surfactant properties and is in fact, receptor-mediated. The above conclusion is supported by the following data: 1. Ichthyotoxicity is not related to its detergency or surfactivity, as indicated by the fact that the lethal concentration is about 1.5 orders of magnitude below its critical micelle concentration value (69 microM) and its liposomal/seawater partition coefficient is low (62-85); 2. The trunkfish is tolerant to its own pahutoxin; 3. Ichthyotoxicity occurs only upon application to the surrounding water, suggesting the existence of externally located receptors; 4. The receptor hypothesis was supported by the aid of equilibrium saturation binding assays revealing the presence of specific binding sites to PHN on the fish gill membranes; 5. The PHN tolerant trunkfish was shown to be devoid of PHN-binding sites. Some chemo-ecological, and environmental implications are discussed.     

液相色谱-质谱测定鸦胆子油脂肪乳注射液在癌症患者体内的血药浓度

目的 建立液相色谱-质谱(LC-MS)法测定癌症患者单剂量滴注鸦胆 子油脂肪乳后体内油酸浓度。方法 用自身对照试验设计,7名癌症患者,第3 天不给药,抽取不同时间点空白血浆样品;第5天,单剂量滴注鸦胆子油脂肪乳 注射液100 mL,滴注开始后,抽取不同时间点血浆样品,60 min滴完,用LC- MS法测定血药浓度。结果 线性范围为2．44-156 mg·L-1;日内、日间变异 系数均<14％;7名癌症患者单剂量滴注鸦胆子油脂肪乳注射液100 mL后,主 要药代动力学参数:tmax=(1．08±0．19)h,Cmax(95．20±29．10)mg·L-1, AUC0-7h=(265．67±59．32)mg·h·L-1,t1／2=(12．14±6．42)h。结论 本法 适用临床测定血浆中油酸浓度。     

利尿酸是打开血-迷路屏障的钥匙

目的观察在不同的时机应用利尿酸以暂时破坏耳蜗血管纹上皮是否能够开放血-迷路屏障,从而促使庆大霉素进入耳蜗或者从耳蜗排出.方法听神经动作电位测试技术,全耳蜗毛细胞计数定量观察技术和荧光偏振免疫法测定庆大霉素浓度的技术被用于以下两个不同目的的实验观察.(1)当庆大霉素血中浓度高于内耳液浓度时,应用利尿酸破坏蜗管外壁以促使更多的庆大霉素进入耳蜗以制备不同程度耳蜗损害的动物模型.(2)当庆大霉素内耳浓度高于血中浓度时,应用利尿酸损坏蜗管外壁以促使蓄积在耳蜗内的庆大霉素从内耳排出以达到挽救毛细胞的目的.结果1.当庆大霉素血中浓度高于内耳液浓度时,注射利尿酸可造成更多的毛细胞损害和听功能障碍,外淋巴中药物的峰值浓度和半衰期浓度也均比单独一次注射庆大霉素动物外淋巴中药物浓度增加一倍,说明同时注射利尿酸可促使更多的庆大霉素从血液进入耳蜗并造成更严重的毛细胞损害.2.当血液中庆大霉素排空之后,注射利尿酸可减少毛细胞数量的损失程度,同时发现延迟注射利尿酸组动物的听力损失程度比不经利尿酸处理动物组有所减轻,外淋巴中药物浓度也比不经利尿酸处理动物组降低一半,说明当GM在耳蜗内蓄积但血清中已经排空时注射EA有助于降低药物在耳蜗内的蓄积并挽救尚未被破坏的毛细胞.结论利尿酸可以做为打开血-迷路屏障的钥匙,但是应用利尿酸开放血-迷路屏障可以产生双向结果,其关键在于注射利尿酸的时机.     

Endogenous urinary steroids in premenopausal women with uterine leiomyomas.

OBJECTIVES: To study the effect of endogenous steroids on the presence of uterine leiomyomas. METHODS: Urine samples of 27 premenopausal women with leiomyomas and 25 age-matched healthy premenopausal women were collected. The concentration of estrogens and androgens in the urine samples of the two groups were determined using a gas chromatography mass spectrometer and the two groups were compared. To study metabolic changes in patients indirectly, the concentration ratios of precursor metabolite to product metabolite of the two groups were also compared. RESULTS: Urinary concentrations of 17beta-estradiol, 5-androstene-3beta, 16beta, 17beta, triol, 11-keto-ethiocholanolone, 11beta-hydroxy-androsterone, 11beta-hydroxy-etiocholanolone, THS, THA, THE, alpha-cortol and beta-cortol were significantly higher in patients than in controls. The concentration ratios of 17beta-estradiol/estrone and 11/beta-hydroxy-ethiocholanolone/11beta-hydroxy-androsterone increased in patients. CONCLUSIONS: The presence of uterine leiomyomas correlates with an increase in urinary concentrations of estrogens and androgens, and it appears to be caused by a decrease in patients' metabolism of steroids.     

用金属磁记忆方法进行缺陷检测

介绍了金属磁记忆检测的原理及其应用方法。铁磁性工件在载荷的作用下,应力和变形集中区会产生最大的漏磁场变化,对漏磁场法向分量的测定可以准确地推断工件的应力集中区。通过对14块对接焊缝钢板分别用磁记忆、超声波方法进行实际检测,验证了磁记忆检测方法的有效性,取得了一些有益的经验。     

人血浆中头孢氨苄浓度高效液相色谱法测定

目的建立高效液相色谱法测定人血浆中头孢氨苄的浓度。方法采用噻克硝唑为内标,色谱柱为YMC ODS-A C18(150 mm×4.6 mm),流动相为乙腈∶甲醇∶pH 4.5的醋酸盐缓冲液(6∶10∶84),流速为1.0 mL/min,检测波长为260 nm。结果头孢氨苄血清浓度在0.101~32.100μg/mL范围内具有良好线性关系,最低定量限为0.101μg/mL,方法回收率为97.5%~103.0%,日内、日间相对标准差均<7%。结论高效液相色谱法简便、准确、灵敏,适用于头孢氨苄血药浓度监测和药代动力学研究。     

HPLC测定人体血浆中替硝唑浓度

目的:建立替硝唑血药浓度测定方法,用于复方替硝唑片血药浓度研究。方法:采用高效液相色谱法。色谱柱为C18柱,流动相为12%乙腈水溶液(pH7.0),检测波长318nm。结果:样品组分在0.2～20μg.ml-1线性良好(r=0.9998),最低血浆药物检测浓度为0.02μg.ml-1。回收率为94.4%～98.3%,日内及日间RSD<5%。结论:本法简便、迅速、灵敏、准确,适合于临床药学研究需要。     

血清中异丙酚的HPLC测定

建立了检测血清中异丙酚的反相高效液相色谱-荧光法.血清样品经含内标百里酚的丙酮溶液直接沉淀后,采用KR100-5 C18柱,甲醇-0.1%三氟醋酸溶液(80:20)为流动相,荧光激发波长为276nm,发射波长为307nm.异丙酚在0.05～12.8μg/ml范围内与峰面积比线性关系良好.检测限为150pg,异丙酚和百里酚的提取回收率均大于90%,批内、批间精密度为1.11%～6.88%.     

大环内酯类抗生素抗分枝杆菌作用的研究

目的研究大环内酯类抗生素抗分枝杆菌的作用。方法分别测定6种大环内酯类抗生素对20种分枝杆菌(包括结核、牛分枝杆菌和18种非结核分枝杆菌)的试管内最低抑菌浓度。结果不同药物显示不同的试管内抗菌作用谱。结论大环内酯类抗生素是临床非结核分枝杆菌病治疗可选择的药物。