Pharmacokinetics of metoprolol in healthy,elderly, non-smoking individuals after a single dose and two weeks of treatment

Summary The effect of long-term treatment on the absorption and dispsoition of metoprolol has been evaluated in 8 healthy, non-smoking, elderly individuals (mean age 74.5 years) and in a control group of 8 healthy, young individuals. Two trace doses of [³H]metoprolol were given i.v., first concomitantly with a single oral 50 mg dose of cold metoprolol, and second, with the morning dose after 2 weeks of treatment with 50 mg b.d. In the elderly, the mean AUC increased by about 45% (p<0.05) over the treatment period, while in the control group the mean AUC was 18% greater (p<0.05) on Day 14 than on Day 1. In the elderly, changes both in pre-systemic elimination and in total body clearance accounted for the elevation of the AUC, whereas reduced first-pass effect appeared to be the major cause of the increased steady-state plasma level in the control group. With the exception of the volume term, V , the pharmacokinetic parameters were not significantly different between the elderly and the young individuals. For this reason, almost identical steady-state plasma levels were attained in the two groups. The results suggest that age-related physiological changes may have some minor effects on the pharmacokinetics of metoprolol, and also that the changes do not lead to significantly altered plasma concentrations compared to those in young individuals.     

低频交变磁场对小鼠骨髓细胞微核率的影响

目的 :研究低频交变磁场对小鼠骨髓嗜多染红细胞微核率的影响。方法 :用强度为 10mT和 15mT的低频交变磁场作用于小鼠后 ,检测其骨髓嗜多染红细胞微核率。结果 :经强度为 10mT的低频交变磁场作用后的小鼠微核率与阴性对照组比较无显著性差异 ,而强度为 15mT的实验组较阴性对照组微核率有明显增高 (P <0 .0 5 ) ,较阳性对照组有非常显著性差异 (P <0 .0 1)。结论 :当小鼠受到 15mT的低频交变磁场作用时 ,细胞微核率增加 ,可能会致突变。     

Stabilization of positive coupled differential‐difference equations with unbounded time‐varying delays

This paper researches the static output‐feedback stabilization of single‐input single‐output (SISO) positive coupled differential‐difference equations (CDDEs) with unbounded time‐varying delays. First, a necessary and sufficient condition is provided for the positivity and asymptotical stability of CDDEs with unbounded time‐varying delays. For this type of system, based on the constructed estimates of its solution, a necessary and sufficient condition on asymptotical stability is provided. Then, based on this criterion, for CDDEs with unbounded time‐varying delays, a kind of static output‐feedback controller is designed to ensure the positivity and asymptotical stability of the corresponding closed‐loop systems. It is also worth pointing out that the controller is designed by the linear programming method without parameterization technique. This design approach can also be applied to the static state feedback stabilization problem of CDDEs with unbounded time‐varying delays. Finally, two illustrative examples are given to show the effectiveness of our results.     

听觉诱发电位的时变滤波叠加

多数诱发电位具有突出的“时变”特性:它们属瞬态反应,在反应前、反应中、反应后各个阶段,电活动的频谱都不断在变化,时变滤波的技术要点:使滤波参数根据电反应的瞬时特性而变,从而更有效地提取有用信号,提高信噪比、缩短操作时间。本文对一般叠加平均处理和时变滤波叠加在动物和人各种听觉诱发电位的信噪比进行了比较。结果显示时变滤波叠加的诱发电位信噪比明显提高,使用时变滤波叠加处理,能达到背景噪声小的效果和反应波形清晰的优点。在大多数情况下,叠加次数可相应地减少,使听觉诱发电位测试效率有所提高。     

提高稀释液浓度测定硫酸卡那霉素含量

目的：探讨按中国药典（2000年版）抗生素微生物检定法测定硫酸卡那霉素含量的最后稀释液浓度范围；方法：应用ZY－300IV型抗生素抑菌圈面积测量分析仪，测定硫酸卡那霉素抑菌圈面积与对数剂量的线性关系范围；结果：测定硫酸卡那霉素含量时，最后稀释液浓度范围在5.5-20.4IU/ml内对数剂量与抑菌圈面积呈直线关系。     

大剂量甲氨蝶呤在急性淋巴细胞白血病应用后两种解毒方法的比较

目的探讨大剂量甲氨蝶呤(MTX)治疗急性淋巴细胞白血病的有效解救方法。方法选取我院收治的急性淋巴细胞白血病患者45例,随机分成观察组(23例)和对照组(22例)。45例患者均应用大剂量MTX进行治疗,观察组患者监测血药浓度并随时调整解救药的剂量,对照组患者应用固定剂量的解救药进行解救。比较两组患者不良反应的发生情况。结果观察组皮肤黏膜损害、胃肠道反应、肝功能损害、肾功能损害、骨髓抑制的发生率均低于对照组,且两组胃肠道反应、肝功能损害、骨髓抑制发生率的差异具有统计学意义(P<0.05)。结论在应用大剂量MTX进行治疗的过程中进行血药浓度的密切监测并及时调整解救药浓度能够达到更好的治疗效果。     

Conversion factors for determining organ doses received by paediatric patients in high-resolution single slice computed tomography with narrow collimation

Estimations of organ doses D_T received during computed tomographic examinations are usually performed by applying conversion factors to basic dose indicators like the computed tomography dose index (CTDI) or the dose-length-product (DLP). In addition to the existing conversion factors for beam apertures of 5 mm or 10 mm, we present new DLP-D_T conversion factors adapted to high-resolution CT (HRCT) examinations of infants and young children with beam apertures of the order of 1 mm and under consideration of bow tie filtration. Calculations are performed on mathematical MIRD phantoms for an age range from 0, 1, 5, 10, 15 up to (for comparison) 30 years by adapting PCXMC, a Monte Carlo algorithm originally developed by STUK (Helsinki, Finland) for dose reconstructions in projection radiography. For this purpose, each single slice CT examination is approximated by a series of corresponding virtual planar radiographies comprising all focus positions. The transformation of CT exposure parameters into exposure parameters of the series of corresponding planar radiographies is performed by a specially developed algorithm called XCT. The DLP values are evaluated using the EGSRay code. The new method is verified at a beam aperture of 10 mm by comparison with formerly published conversion factors. We show that the higher spatial resolution leads to an enhanced DLP-D_T conversion factor if a small organ (e. g. thyroid gland, mammae, uterus, ovaries, testes) is exactly met by the chosen CT slice, while the conversion factor is drastically reduced if the chosen CT slice is positioned above or below the organ. This effect is utilized for dose-saving examinations with only a few single slices instead a full scan, which technique is applied in about 10% of all paediatric chest CT examinations.     

Molecular action mechanisms of solar infrared radiation and heat on human skin

The generation of ROS underlies all solar infrared-affected therapeutic and pathological cutaneous effects. The signaling pathway NF-kB is responsible for the induced therapeutic effects, while the AP-1 for the pathological effects. The different signaling pathways of infrared-induced ROS and infrared-induced heat shock ROS were shown to act independently multiplying the influence on each other by increasing the doses of irradiation and/or increasing the temperature.The molecular action mechanisms of solar infrared radiation and heat on human skin are summarized and discussed in detail in the present paper. The critical doses are determined. Protection strategies against infrared-induced skin damage are proposed.     

不同剂量硬膜外分娩镇痛对产后尿潴留的影响

目的探讨不同剂量下罗哌卡因联合舒芬太尼硬膜外分娩镇痛方案安全性和对产后尿潴留的影响。方法选取2018年5月-2019年5月本院妇产科收治的拟行硬膜外分娩镇痛下自然分娩的初产妇80例,随机分为甲方案组和乙方案组,每组40例,甲方案组产妇采取0.1%罗哌卡因+0.3μg/mL舒芬太尼的硬膜外分娩镇痛方案,乙方案组产妇采取0.075%罗哌卡因+0.5μg/mL舒芬太尼的硬膜外分娩镇痛方案,比较两组产妇的视觉模拟评分(VAS)、尿潴留、其他不良反应和新生儿出生后Apgar评分。结果结果显示,两组的镇痛时间差异无统计学意义;与此同时,在子宫颈开口3 cm时(T0)、分娩镇痛后30 min(T1)、宫颈口开口10 cm时(T2)、分娩即刻(T3)和分娩后2 h时(T4)5个时间点的疼痛评分差异均无统计学意义;但麻醉后的其他时间点的疼痛评分与T0比较,均具有统计学意义。甲方案组尿潴留发生率为5.00%,低于乙方案的20.00%,差异具有统计学意义(χ^2=4.114,P=0.043)。两组产妇分娩的新生儿在出生后l min、5 min和10 min时的Apgar评分差异均无统计学意义(P>0.05)。结论两种剂量的分娩镇痛方案均可有效缓解分娩疼痛,但在0.1%罗哌卡因+0.3μg/mL舒芬太尼剂量下产后尿潴留的发生风险更小。