硒缺乏与硒中毒

硒是人体必须的一种微量元素，只占人体重量的万分之一以下，不能在体内合成，必须从食物中摄取。尽管硒在人体内的含量非常少，而且每日摄入量也极微，但却在人体的机能中发挥着极其重要的作用。近十几年来，对于硒与儿童健康的关系，已成为研究领域十分活跃的课题之一。     

硒与硒酵母的药理及临床研究概述

本文对我国近年来硒的基础研究和硒酵母片的临床研究作了简要的概述。     

分光光度法测定富硒蛋粉中的硒含量

目的 研究用分光光度法测定富硒蛋粉中硒含量的方法.方法 采用分光光度法测定,检测波长731 nm.结果 富硒蛋粉中硒浓度在0～0.40 μg/ml范围内与吸收度呈线性关系(r=0.9987).方法 回收率为96.8%～101.6%,RSD为2.44%.结论 该方法简便、灵敏、准确,可用于富硒蛋粉中的硒含量测定.     

如何补硒

硒对人体是一种很有益的必需微量元素，它可以抗癌防癌，防治心血管病，治疗克山病和大骨节病，防衰老，防治关节炎、肝病等，体内如果缺硒就会出现相应病症，那么如何补硒呢? 　　许多缺硒地区，光靠每天从食物中摄取硒是不足以保证健康的。美国、加拿大、澳大利亚、西欧国家及我国都是明显的地区性严重缺硒的国家。粗略地估算平均一个美国人每天的硒摄入量是70～100毫克，而我国大体上只有30～70微克，而一些硒专家认为，为了维持人的生理活动的正常健康，每天摄入量应为150～200微克在补硒中还要考虑各种对硒有拮抗效应元素的摄入量。例如，有些地区的砷含量相应高，则相应地应该提高硒的摄入量。 　　补硒的药物有亚硒酸钠，该药在我国克山病地区已得到应用，并收到良好效果。除了口服外，还可把该药掺在食盐中或粮食中作为群众性给药的方式。口服剂量以元素硒计，成人约每天250微克，儿童50～100微克，这样的剂量非常安全。 　　还有一种大家公认经特殊方法培养的含硒酵母，例如面包酵母或啤酒酵母即是理想的硒药剂，硒酵母主要优点是它比无机硒盐更容易消化吸收，且副作用和可能的毒性较小。 　　在提高血硒水平方面，硒酵母比亚硒酸钠有明显的优越性，其效率比后者大20倍以上。 　　目前，我国已开始了合成含硒酵母的工作和用于临床治疗缺硒病人。(孙乃强)     

硒和硒化物的药理及药效学研究

硒是人体所必需的微量元素之一，为谷胱甘肽过氧化物酶的重要成分，能消除体内有害自由基，维护正常生理功能。硒及硒化物可防治多种与硒缺乏相关的疾病。本文综述近年来有关硒及硒化物的药理和药效学研究进展。     

矽肺患者的血清硒及硒蛋白P

目的本研冤的目的是观祭矽师病思看血搏中硇的存在状态,测量血椅硇及蚋赁日P（SeP）的浓度,并探讨它们与矽肺的关系。方法我们进行了一项回顾性病例对照研究,随机抽取了本院7l例矽肺患者作为病例组,并选取38例健康人作为对照组,分别进行了血清硒和硒蛋白P的测定。血清硒水平的测定采用电热原子吸收分光光度法,而SeP的水平采用夹心酶联免疫法测定。统计方法采用Spearman等级相关分析法对血清硒和硒蛋白P之间的关系进行评估,采用Mann—Whitney检验对两组间血清硒和硒蛋白P之间的差异进行评估。结果病例组平均血清硒和硒蛋白P的浓度分别为69．0肛g／L和4．5mg／L,显著低于对照组125．Owg／L和6．2mg／L。两组中血清硒的浓度与硒蛋白P呈正相关（rho=0．778,P〈0．001;rho=0．769,P〈0．001）。Ⅲ期矽肺患者的血清硒和SeP的水平显著低于Ⅰ、Ⅱ期矽肺患者。结论矽肺患者血清硒和硒蛋白P浓度较正常人低,并且与病情发展呈正相关。     

分光光度法测定富硒蛋粉中的硒含量

目的研究用分光光度法测定富硒蛋粉中硒含量的方法。方法采用分光光度法测定，检测波长731nm。结果富硒蛋粉中硒浓度在0—0．40μg／ml范围内与吸收度呈线性关系（r=0．9987）。方法回收率为96．8％-101．6％，RSD为2．44％。结论该方法简便、灵敏、准确，可用于富硒蛋粉中的硒含量测定。     

硒与甲状腺

硒是一种人体必需的微量元素。参与体内多种代谢活动,与多种疾病的发生有关。硒与甲状腺的关系更为密切。它不仅参与了甲状腺激素的合成和代谢．而且与自身免疫性甲状腺病、甲状腺癌的发生和发展密切相关。硒对甲状腺疾病的防治作用正在受到人们的广泛关注。本文将就硒与甲状腺生理、甲状腺疾病发生和防治中的作用进行综述,以提高人们对硒在甲状腺疾病防治中作用的认识。     

荧光分光光度法测定硒多糖胶囊中的硒含量

目的 测定硒多糖胶囊中硒的舍量。方法 采用2，3-二氨基萘荧光分析法测定硒的含量。结果 平均回收率为98．2%。结论 此法特异性强，精密度高，快速而简便。     

Pharmacokinetics of eltoprazine in healthy male subjects after single dose oral and intravenous administration.

The kinetics, safety and tolerability of eltoprazine hydrochloride were studied in an open, cross-over, partially randomised design after single oral (8 mg) and intravenous (3 and 8 mg) doses to 12 healthy male subjects. After intravenous administration, the mean t1/2 ranged from 7 to 9 h, the MRT was 11 h, CL was 487 +/- 148 (3 mg dose) and 471 +/- 56 (8 mg dose) ml kg-1 h-1, while CLR was 226 +/- 124 (3 mg dose) and 189 +/- 38 (8 mg dose) ml kg-1 h-1. The Vss was 3.3 +/- 0.7 (3 mg dose) and 3.8 +/- 0.5 (8 mg dose) 1 kg-1. Cumulative renal excretion was 40%. The AUC and the cumulative urinary excretion were directly proportional to dose within the range of 3-8 mg. Values of tmax varied from 1 to 4 h after oral administration. The mean Cmax value was 24 ng ml-1 after an oral dose of 8 mg. The plasma elimination half-life after oral administration was 9.8 +/- 3.9 h. Absolute oral bioavailability was 110 +/- 32%. Dose-dependent somnolence was observed.     

Concurrent administration of antacids and prednisone: effect on serum levels of prednisolone.

1 Specific radioimmunoassays have been developed for the measurement of prednisolone and prednisone in serum. 2 Serum prednisolone levels have been measured following the administration of prednisone both with and without antacids. 3 There were no significant differences in the values of Cmax (mean +/- s.d.) (251 +/- 80 ng/ml with, 245 +/- 69 ng/ml without antacid), AUC (1430 +/- 469 ng ml-1 h-1 with, 1406 +/- 530 ng ml-1 h-1 without antacid) or Tmax (1.6 +/- 0.6 h with, 1.6 +/- 0.8 h without antacid). 4 Serum prednisone levels were less than 20% of prednisolone levels at all time intervals in the subjects studied. 5 Concurrent antacid administration has no significant effect on serum prednisolone levels attained.     

毛兰素注射液在大鼠体内药动学研究

目的阐明毛兰素注射液在SD大鼠体内药动学规律。方法 SD大鼠分别单次和隔天、每隔一个半衰期一次多剂量静脉注射毛兰素注射液。采用高效液相色谱-质谱联用（HPLC-MS）测定大鼠静脉注射后不同时间大鼠血浆中毛兰素的血药浓度。结果大鼠单次静脉注射25,50,100mg·kg-1毛兰素注射液的主要药动学参数为：T1/2β分别为3.66,3.75,3.89h;AUC0-12分别为1453.0,3041.6,6731.6ng·mL-1·h;AUC0-∞分别为1462.0,3077.3,6788.7ng·mL-1·h;Vd分别为11.67,10.37,3.38L·kg-1;CL分别为0.049,0.089,0.024L·kg-1·h-1;MRT分别为0.18,0.28,0.21h;50mg·kg-1剂量的毛兰素注射液隔日给药5次其药动学参数与单次给药相近;而50mg·kg-1剂量的毛兰素注射液每隔一个半衰期一次给药5次的T1/2β为5.43h,AUC（S0）（0-t）为9800.8ng·mL-1·h。结论毛兰素注射液在大鼠体内的动力学过程与剂量相关,毛兰素注射液单剂量给药的体内药动学符合开放型二房室模型,T1/2β与给药剂量与关,表明毛兰素在大鼠体内的消除过程符合一级动力学规律。隔日多剂量给药的消除过程亦符合一级动力学规律;而每隔一个半衰期一次多剂量给予50mg·kg-1剂量的毛兰素其在大鼠体内则呈非线性消除。     

Effect of dehydration and hyperosmolal hydration on lignocaine and metabolites disposition in conscious rabbits.

1. The present study aimed to investigate the effect of dehydration and hyperosmolal hydration on the disposition of lignocaine and two of its metabolites, monoethylglycinexylidide (MEGX) and glycinexylidide (GX). 2. Lignocaine was infused to three groups of conscious rabbits: controls, rabbits previously deprived of water for 48 h and rabbits receiving an infusion of 2.5% NaCl. 3. In dehydrated and hyperosmolal-hydrated rabbits, plasma osmolality was 321 +/- 1 and 313 +/- 1 mOsm kg-1, respectively (P < 0.01 compared to controls, 285 +/- 1 mOsm kg-1). In dehydrated animals, baseline values of plasma arginine vasopressin (AVP) concentrations and plasma renin activity (PRA) were higher than in controls, i.e. 12.4 +/- 1.4 pg ml-1 and 15.4 +/- 1.7 ng AI ml-1 h-1 vs. 3.4 +/- 0.2 pg ml-1 (P < 0.01), and 5.1 +/- 0.6 ng AI ml-1 h-1 (P < 0.01), respectively; atrial natriuretic peptide (ANP) decreased from 55 +/- 11 to 32 +/- 4 pg ml-1 (P < 0.05). Compared to controls, hyperosmolal hydration only increased AVP to 15.5 +/- 0.7 pg ml-1 (P < 0.01). 4. Under both experimental conditions, lignocaine plasma concentrations were almost double (P < 0.01) those in controls, due to a lower systemic clearance, e.g. 54 +/- 3 and 59 +/- 1 vs. 96 +/- 5 ml min-1 kg-1, respectively. Plasma levels of MEGX increased (P < 0.01) only in dehydrated animals, although GX plasma concentrations were augmented (P < 0.01) about three fold in both groups of animals.(ABSTRACT TRUNCATED AT 250 WORDS)     

Pharmacokinetics of oral nifedipine: relevance of the distribution phase

Pharmacokinetics of oral Nifedipine was studied in 12 Mexican young healthy volunteers, six men and six women, who received a 10 mg capsule. Plasma levels were determined by a nifedipine specific HPLC assay. Experimental data were fitted and pharmacokinetic parameters were calculated using an open two compartment model. No statistically significant difference was detected between men and women, thus both sexes were considered as a single population. Nifedipine plasma levels rose rapidly (ka = 8.46 +/- 1.96 h-1) reaching a maximum concentration of 145 +/- 23 ng/ml in 0.61 +/- 0.07 h. Plasma levels then decayed with a distribution phase (alpha = 1.98 +/- 0.40 h-1, t1/2 alpha = 0.46 +/- 0.06 h) and a terminal elimination phase (beta = 0.17 +/- 0.03 h-1, t1/2 beta = 4.98 +/- 0.55 h). AUC was 384 +/- 41 ng h/ml. Values of AUC and t1/2 beta were higher than those reported by other authors. Differences in the AUC could be due to ethnic origin, environmental factors or nutritional habits. Ten subjects presented plasma concentration-time curves in which the distribution phase was clearly distinguishable, having a ka/alpha relationship higher than 1.5. For the other two subjects, the distribution phase was not apparent and ka/alpha was lower than 1.5. The results show that an adequate characterization of the distribution phase is required if one pretends to use pharmacokinetic data for dosage regimen design.     

Studies of mefloquine bioavailability and kinetics using a stable isotope technique: a comparison of Thai patients with falciparum malaria and healthy Caucasian volunteers.

1 A mefloquine hydrochloride tablet (250 mg base equivalent to 4.8 +/- 0.6 mg kg-1; mean +/- s.d.) and deuterium labelled mefloquine hydrochloride solution (250 mg base) were given to six adult male Thai patients with acute falciparum malaria and six healthy Swiss adult male volunteers (equivalent to 3.5 +/- 0.1 mg kg-1). 2 The relative bioavailability of the tablet formulation derived from comparison of the areas under the plasma concentration-time curves was similar in both groups; 87 +/- 11% and 89 +/- 10% (mean +/- s.d.). 3 The rate of drug absorption appeared to be similar in the two groups but peak plasma mefloquine concentrations were approximately three times higher in the Thai patients (1004 +/- 276 ng ml-1 for the tablet and 1085 +/- 280 ng ml-1 for the suspension) compared with the Swiss volunteers (319 +/- 73 ng ml-1 for the tablet, and 369 +/- 121 ng ml-1 for the suspension). 4 Estimates of the oral clearance CLpo of unlabelled mefloquine were significantly lower (17.5 +/- 4.4 ml h-1 kg-1) in the Thai patients compared with 28.8 +/- 3.5 ml h-1 kg-1 in the Swiss volunteers; P less than 0.05). Terminal elimination half-lives were significantly shorter in the patients (10.3 +/- 2.5 days) than in the volunteers (16.7 +/- 1.9 days; P less than 0.005). Differences of a similar magnitude were observed when comparing the pharmacokinetic parameters derived from the deuteromefloquine plasma concentrations. 5 Both genetic and disease related factors are likely to account for the large pharmacokinetic differences between the two groups.(ABSTRACT TRUNCATED AT 250 WORDS)