An evaluation of rectal artesunate for the pre-hospital management of severe malaria

ABSTRACT

Introduction

Severe falciparum malaria stills accounts for around half a million childhood deaths per year in sub-Saharan Africa. Prompt treatment of sick children close to home starting with artesunate given rectally by appropriately trained people can be lifesaving.     

Opposite malaria and pregnancy effect on oral bioavailability of artesunate – a population pharmacokinetic evaluation

Aim

The aim was to compare the pharmacokinetic properties of artesunate and dihydroartemisinin in the same women: i) pregnant with acute uncomplicated malaria on day 1 and 2, ii) pregnant with convalescent malaria on day 7 and iii) in a healthy state 3 months post-partum on day 1, 2 and 7.

Methods

Non-linear mixed-effects modelling was used to compare plasma concentration–time profiles of artesunate and dihydroartemisinin over 7 days of treatment following oral and intravenous artesunate administration to pregnant women with uncomplicated Plasmodium falciparum malaria during their second or third trimesters of pregnancy. The same women were restudied 3 months after delivery when fully recovered. Non-compartmental results of the same study have been published previously.

Results

Twenty pregnant patients on the Thailand-Myanmar border were studied and 15 volunteered to be restudied 3 months post-partum. Malaria and pregnancy had no effect on the pharmacokinetic properties of artesunate or dihydroartemisinin after intravenous artesunate administration. However, malaria and pregnancy had opposite effects on the absorption of orally administered artesunate. Malaria increased the absolute oral bioavailability of artesunate by 87%, presumably by inhibiting first pass effect, whereas pregnancy decreased oral bioavailability by 23%.

Conclusions

The population pharmacokinetic analysis demonstrated opposite effects of malaria and pregnancy on the bioavailability of orally administered artesunate. Lower drug exposures during the second and third trimesters of pregnancy may contribute to lower cure rates and thus the development of drug resistance. Dose optimization studies are required for artesunate containing artemisinin-based combination therapies (ACTs) in later pregnancy.     

双氢青蒿素诱导肿瘤细胞铁死亡及其机制研究

目的阐明双氢青蒿素(DHA)诱导肿瘤细胞铁死亡的作用及其机制。方法利用3,3′,5,5′-四甲基联苯胺(TMB)检测DHA与FeSO_4体外芬顿样(Fenton)反应生成氧自由基(·OH)的能力;MTT法检测DHA对人肝癌HepG2细胞的毒性(包括FeSO_4与去铁胺预处理组)。MTT法考察谷胱甘肽(GSH)与铁死亡抑制剂(Fer-1)对DHA细胞毒性的影响;采用DCFH-DA染料考察DHA(包括FeSO_4预处理组)诱导的细胞内活性氧的生成能力;采用C11-BODIPY581/591与DiO分别考察DHA(包括FeSO_4预处理组)对细胞内脂质过氧化物生成能力以及细胞膜结构的影响;利用谷胱甘肽过氧化物酶4(GPX-4)试剂盒测定DHA(包括FeSO_4预处理组)对HepG2细胞内GPX-4活性的影响。结果 Fe~(2+)能够催化DHA发生芬顿样反应并生成·OH;DHA的半数抑制浓度(IC_(50))为(39.96±8.78)μmol/L,FeSO_4与去铁胺分别能够增加或者降低DHA的细胞毒性;DHA处理后细胞内活性氧含量与脂质过氧化物含量升高,细胞形态变大,细胞膜呈散点状分布并呈现解离状态。FeSO_4预处理组与DHA组相比较进一步增加细胞内活性氧含量与脂质过氧化物含量,并且细胞膜形态完全破坏。FeSO_4能够增强DHA对GPX-4活性的抑制作用。结论 DHA通过芬顿样反应升高细胞内活性氧而最终诱导肿瘤细胞铁死亡。另外,外源性铁可以加速DHA发生芬顿样反应进而加速肿瘤细胞铁死亡的发生与发展。     

双氢青蒿素诱导肿瘤细胞凋亡的信号通路研究进展

双氢青蒿素作为青蒿素的重要衍生物,是我国自行研制出的抗疟新药。近些年来,人们对双氢青蒿素进行了多方面的研究,在抗肿瘤研究方面有许多新进展,发现其诱导肿瘤细胞凋亡的机制与多条信号通路有关,例如PI3K/Akt、MAPK、STAT3、Wnt/β-catenin、NF-κB等信号通路。通过对作用机制的深入研究和阐述有望发现双氢青蒿素的新适应症,使其在临床上的应用更加广泛。     

蒿甲醚和双氢青蒿素治疗维和部队疟疾93例分析

目的 为了保证维和部队的任务完成及官兵的身体健康,防治维和部队的疟疾患者并总结疟疾的防治经验.方法 对所属维和部队官兵参与进行抗疟药物分组治疗效果观察.结果 双氢青蒿素(科泰新)防治效果肯定,用于进人高疟区的易感人群疟疾防治效果显著.结论 蒿甲醚对疟疾的疗效肯定;双氢青蒿素作为一种新的选择更适应未来的战争需要.     

二氢青蒿素对结肠癌细胞HCT116凋亡基因表达图谱的影响

 摘要: 目的 探讨二氢青蒿素（DHA）诱导的结肠癌细胞HCT116凋亡基因差异表达。方法 利用基因芯片RT ProfilerTM PCR Array Human Apoptosis 和实时定量PCR方法对DHA组和对照组HCT116细胞的84种凋亡基因表达进行mRNA水平的检测。结果 DHA组细胞中,35种凋亡基因表达水平显著改变,TNFα、TRAILR、CASP、GADD45等促凋亡基因的表达显著上调;BCL2、AKT、BAD等抗凋亡基因表达显著下调。结论 DHA通过复杂的分子机制诱导HCT116细胞凋亡。     

双氢青蒿素人对急性髓系白血病HL-60细胞凋亡的诱导作用

目的 探讨双氢青蒿素诱导人急性髓系白血病HL-60细胞凋亡的作用和机制.方法 用二甲氧唑黄细胞增殖及细胞毒性检测试剂盒检测双氢青蒿素对HL-60细胞生长的抑制作用,Annexin V-FITC/PI染色流式细胞仪检测细胞凋亡,流式细胞仪检测细胞内线粒体膜电位变化,分光光度法检测细胞Caspase-3活性变化.结果 双氢...     

Dihydroartemisinin suppresses ovalbumin-induced airway inflammation in a mouse allergic asthma model

Abstract

Asthma is a complex disease characterized by reversible airway obstruction, airway hyper-responsiveness (AHR) and chronic inflammation of the airways. Dihydroartemisinin (DHA), a semi-synthetic derivative of artemisinin isolated from the traditional Chinese herb Artemisia annua, has been shown to possess antimalarial and antitumor activities, but whether it can be used in asthma treatment has not been investigated. In this study, we attempted to determine whether DHA regulates inflammatory mediators in the ovalbumin (OVA)-induced mouse asthma model. BALB/c mice were sensitized and challenged by OVA to induce chronic airway inflammation. The intragastrical administration of DHA at 30?mg/kg significantly decreased the number of infiltrating inflammatory cells, T-helper type 2 (Th2) cytokines, OVA-specific immunoglobulin E (IgE) and AHR. Treatment with DHA also attenuated OVA-induced mRNA expression of Muc5ac and chitinase 3-like protein 4 (Ym2) in lung tissues. In addition, lung histopathological studies revealed that DHA inhibited inflammatory cell infiltration and mucus hypersecretion. Then signal transduction studies showed that DHA significantly inhibited extracellular signal-regulated protein kinase (ERK), p38 mitogen-activated protein kinase phosphorylation. DHA also inhibited nuclear factor-κB (NF-κB) activation via the inhibition of phosphorylation of IκBα. These findings provide new insight into the immunopharmacological role of DHA in terms of its effects in a mouse model of asthma.