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https://www.readbyqxmd.com/read/28531230/identifying-artemisinin-resistance-from-parasite-clearance-half-life-data-with-a-simple-shiny-web-application
#1
Sai Thein Than Tun, Yoel Lubell, Arjen M Dondorp, Tom Fieldman, Kyaw Myo Tun, Olivier Celhay, Xin Hui Chan, Sompob Saralamba, Lisa J White
The emergence of artemisinin-resistant Plasmodium falciparum malaria is a major threat to malaria elimination. New tools for supporting the surveillance of artemisinin resistance are critical for current and future malaria control and elimination strategies. We have developed an open-access, user-friendly, web-based tool to analyse parasite clearance half-life data of P. falciparum infected patients after treatment with artemisinin derivatives, so that resistance to artemisinin can be identified. The tool can be accessed at bit...
2017: PloS One
https://www.readbyqxmd.com/read/28529044/synthesis-and-anticancer-activity-of-novel-aza-artemisinin-derivatives
#2
Sampad Jana, Shabina Iram, Joice Thomas, Sandra Liekens, Wim Dehaen
Three series of aza-artemisinin derivatives were synthesized for studies of anticancer activity. The first series of compounds were prepared via copper(I)-catalyzed azide alkyne cycloaddition, so called "click reaction", starting from propargyl derivatives of 11-aza-artemisinin and various azides, whereas the second and third series of compounds were prepared by triazolization reaction starting from enolizable ketones and primary amines connected to artemisinin. In vitro studies of the 23 synthesized artemisinin derivatives unveiled that 9 compounds displayed antiproliferative activity in the low micromolar range, with 5d being the most promising compound showing 50% inhibition of Cem and HeLa cell growth at 0...
April 30, 2017: Bioorganic & Medicinal Chemistry
https://www.readbyqxmd.com/read/28526743/systematic-identification-of-functional-residues-of-artemisia-annua-amorpha-4-11-diene-synthase
#3
Xin Fang, Jian-Xu Li, Jin-Quan Huang, You-Li Xiao, Peng Zhang, Xiao-Ya Chen
Terpene synthases (TPSs) are responsible for the extremely diversified and complex structure of terpenoids. Amorpha-4,11-diene synthase (ADS) has a high (90%) fidelity in generating the sesquiterpene precursor for biosynthesis of artemisinin, an antimalarial drug, however, little is known about how active site residues of ADS involved in the carbocation rearrangement and cyclization reactions. Here, we identify seven residues that are key to most of the catalytic steps in ADS. By structural modeling and amino acid sequence alignments of ADS with two functionally relevant sesquiterpene synthases from Artemisia annua, we performed site-directed mutagenesis and found that a single substitution, T296V, impaired the ring closure activity almost completely, and tetra-substitutions (L374Y/L404V/L405I/G439S) led to an enzyme generating 80% monocyclic bisabolyl-type sesquiterpenes, whereas a double mutant (T399L/T447G) showed compromised activity in regioselective deprotonation to yield 34...
May 19, 2017: Biochemical Journal
https://www.readbyqxmd.com/read/28526075/testing-times-trends-in-availability-price-and-market-share-of-malaria-diagnostics-in-the-public-and-private-healthcare-sector-across-eight-sub-saharan-african-countries-from-2009-to-2015
#4
Kara Hanson, Catherine Goodman
BACKGROUND: The World Health Organization guidelines have recommended that all cases of suspected malaria should receive a confirmatory test with microscopy or a malaria rapid diagnostic test (RDT), however evidence from sub-Saharan Africa (SSA) illustrates that only one-third of children under five with a recent fever received a test. The aim of this study was to evaluate availability, price and market share of microscopy and RDT from 2009/11 to 2014/15 in 8 SSA countries, to better understand barriers to improving access to malaria confirmatory testing in the public and private health sectors...
May 19, 2017: Malaria Journal
https://www.readbyqxmd.com/read/28521811/the-malaria-testing-and-treatment-landscape-in-mainland-tanzania-2016
#5
Daniel Michael, Sigsbert Patila Mkunde
BACKGROUND: Understanding the key characteristics of malaria testing and treatment is essential to the control of a disease that continues to pose a major risk of morbidity and mortality in mainland Tanzania, with evidence of a resurgence of the disease in recent years. The introduction of artemisinin combination therapy (ACT) as the first-line treatment for malaria, alongside policies to promote rational case management following testing, highlights the need for evidence of anti-malarial and testing markets in the country...
April 24, 2017: Malaria Journal
https://www.readbyqxmd.com/read/28521791/exploring-the-role-of-socioeconomic-factors-in-the-development-and-spread-of-anti-malarial-drug-resistance-a-qualitative-study
#6
Philip Emeka Anyanwu, John Fulton, Etta Evans, Timothy Paget
BACKGROUND: Malaria remains a global health issue with the burden unevenly distributed to the disadvantage of the developing countries of the world. Poverty contributes to the malaria burden as it has the ability to affect integral aspects of malaria control. There have been renewed efforts in the global malaria control, resulting in reductions in the global malaria burden over the last decade. However, the development of resistance to artemisinin-based combination therapy threatens the sustainability of the present success in malaria control...
May 18, 2017: Malaria Journal
https://www.readbyqxmd.com/read/28521306/visible-light-sensitive-titanium-dioxide-nanoplatform-for-tumor-responsive-fe2-liberating-and-artemisinin-delivery
#7
Huijuan Zhang, Hongling Zhang, Xing Zhu, Xiaoge Zhang, Qianqian Chen, Jianjiao Chen, Lin Hou, Zhenzhong Zhang
Artemisinin is a kind of Fe2+-dependent drugs. Artemisinin and Fe2+ co-transport systems can improve its anti-tumor effect. In this study, a visible light-sensitive nanoplatform (HA-TiO2-IONPs/ART) was developed. Detailed investigation demonstrated that HA-TiO2-IONPs/ART could realize Fe2+ and artemisinin synchronous co-delivery and tumor-responsive release. This feature enhanced the anti-tumor efficiency of artemisinin significantly. In vitro results proved that hyaluronic acid modification could improve the biocompatibility, dispersion stability and cytophagy ability of nanocarriers...
May 5, 2017: Oncotarget
https://www.readbyqxmd.com/read/28513196/synthesis-and-in-vivo-antimalarial-activity-of-novel-naphthoquine-derivatives-with-linear-cyclic-structured-pendants
#8
Ling Tang, Zhuchun Bei, Yabin Song, Likun Xu, Hong Wang, Dongna Zhang, Yuanyuan Dou, Kai Lv, Hongquan Wang
AIM: Naphthoquine (NQ) was discovered by our institute as an antimalarial candidate in 1980s, and currently employed as an artemisinin-based combination therapy partner drug. Resistance to NQ was found in mouse model in laboratory, and might emerge in future as widely used. METHODOLOGY: We herein report the design and synthesis of NQ derivatives by replacing t-butyl moiety with linear/cyclic structured pendants. All the target compounds 6a-l and intermediates 5a-h were tested for their in vivo antimalarial activity against Plasmodium berghei K173 strain in mice...
May 17, 2017: Future Medicinal Chemistry
https://www.readbyqxmd.com/read/28511713/artemisinin-based-combination-therapy-in-pregnant-women-in-zambia-efficacy-safety-and-risk-of-recurrent-malaria
#9
Michael Nambozi, Jean-Bertin Bukasa Kabuya, Sebastian Hachizovu, David Mwakazanga, Joyce Mulenga, Webster Kasongo, Jozefien Buyze, Modest Mulenga, Jean-Pierre Van Geertruyden, Umberto D'Alessandro
BACKGROUND: In Zambia, malaria is one of the leading causes of morbidity and mortality, especially among under five children and pregnant women. For the latter, the World Health Organization recommends the use of artemisinin-based combination therapy (ACT) in the second and third trimester of pregnancy. In a context of limited information on ACT, the safety and efficacy of three combinations, namely artemether-lumefantrine (AL), mefloquine-artesunate (MQAS) and dihydroartemisinin-piperaquine (DHAPQ) were assessed in pregnant women with malaria...
May 16, 2017: Malaria Journal
https://www.readbyqxmd.com/read/28511056/elimination-of-schistosoma-mansoni-in-infected-mice-by-slow-release-of-artemisone
#10
Daniel Gold, Mohammed Alian, Avraham Domb, Yara Karawani, Maysa Jbarien, Jacques Chollet, Richard K Haynes, Ho Ning Wong, Viola Buchholz, Andreas Greiner, Jacob Golenser
The current treatment of schistosomiasis is based on the anti-helminthic drug praziquantel (PZQ). PZQ affects only the adult stages of schistosomes. In addition, resistance to PZQ is emerging. We suggest a drug, which could serve as a potential alternative or complement to PZQ, and as a means of treating infections at earlier, pre-granuloma stage. Derivatives of the peroxidic antimalarial drug artemisinin have been indicated as alternatives, because both plasmodia and schistosomes are blood-feeding parasites...
May 4, 2017: International Journal for Parasitology, Drugs and Drug Resistance
https://www.readbyqxmd.com/read/28508166/toxoplasma-gondii-and-schizophrenia-a-review-of-published-rcts
#11
REVIEW
Sam D Chorlton
Over the last 60 years, accumulating evidence has suggested that acute, chronic, and maternal Toxoplasma gondii infections predispose to schizophrenia. More recent evidence suggests that chronically infected patients with schizophrenia present with more severe disease. After acute infection, parasites form walled cysts in the brain, leading to lifelong chronic infection and drug resistance to commonly used antiparasitics. Chronic infection is the most studied and closely linked with development and severity of schizophrenia...
May 15, 2017: Parasitology Research
https://www.readbyqxmd.com/read/28499218/dissolution-and-physicochemical-stability-enhancement-of-artemisinin-and-mefloquine-co-formulation-via-nano-confinement-with-mesoporous-sba-15
#12
Kumaran Letchmanan, Shou-Cang Shen, Wai Kiong Ng, Reginald B H Tan
The objective of this study is to enhance the dissolution rate, supersaturation and physicochemical stability of combination of two poorly water-soluble anti-malarial drugs, artemisinin (ART) and mefloquine (MFQ), by encapsulating them inside mesoporous silica (SBA-15) via co-spray drying. Characteristic studies such as powder X-ray diffraction (PXRD), transmission electron microscopy (TEM) and scanning electron microscope (SEM) clearly indicate the amorphization of the crystalline drugs. ART/MQF/SBA-15 formulations show a superior dissolution enhancement with a burst release of more than 95% of drugs within 30min...
May 2, 2017: Colloids and Surfaces. B, Biointerfaces
https://www.readbyqxmd.com/read/28495384/medicinal-chemistry-of-antischistosomal-drugs-praziquantel-and-oxamniquine
#13
REVIEW
Vinícius Barros Ribeiro da Silva, Bruna Rafaella Koresch Leiva Campos, Jamerson Ferreira de Oliveira, Jean-Luc Decout, Maria do Carmo Alves de Lima
Neglected tropical diseases (NTDs) are a group of diseases that, besides prevailing in poverty conditions, contribute to the maintenance of social inequality, being a strong barrier to a country development. Schistosomiasis, a NTD, is a tropical and subtropical disease caused by the trematode Schistosoma mansoni (Africa, Middle East, Caribbean, Brazil, Venezuela, Suriname), japonicum (China, Indonesia, the Philippines), mekongi (several districts of Cambodia and the Lao People's Democratic Republic), intercalatum and guianensis (areas of tropical rainforests in Central Africa) and hematobium (Middle East Africa, Corsica, France) whose adult forms inhabit the mesenteric vessels of the host, while the intermediate forms are found in the aquatic gastropod snails of the genus Biomphalaria...
April 27, 2017: Bioorganic & Medicinal Chemistry
https://www.readbyqxmd.com/read/28494763/artemisinin-resistance-without-pfkelch13-mutations-in-plasmodium-falciparum-isolates-from-cambodia
#14
Angana Mukherjee, Selina Bopp, Pamela Magistrado, Wesley Wong, Rachel Daniels, Allison Demas, Stephen Schaffner, Chanaki Amaratunga, Pharath Lim, Mehul Dhorda, Olivo Miotto, Charles Woodrow, Elizabeth A Ashley, Arjen M Dondorp, Nicholas J White, Dyann Wirth, Rick Fairhurst, Sarah K Volkman
BACKGROUND: Artemisinin resistance is associated with delayed parasite clearance half-life in vivo and correlates with ring-stage survival under dihydroartemisinin in vitro. Both phenotypes are associated with mutations in the PF3D7_1343700 pfkelch13 gene. Recent spread of artemisinin resistance and emerging piperaquine resistance in Southeast Asia show that artemisinin combination therapy, such as dihydroartemisinin-piperaquine, are losing clinical effectiveness, prompting investigation of drug resistance mechanisms and development of strategies to surmount emerging anti-malarial resistance...
May 12, 2017: Malaria Journal
https://www.readbyqxmd.com/read/28492080/artemisinin-luminol-chemiluminescence-for-forensic-bloodstain-detection-using-smart-phone-as-detector
#15
Wenyue Gao, Chao Wang, Kateryna Muzyka, Shimeles Addisu Kitte, Jianping Li, Wei Zhang, Guobao Xu
Forensic luminol chemiluminescence test is one of the most sensitive and popular methods for the determination of latent bloodstains. It mainly uses hydrogen peroxide or sodium perborate as coreactants. The easy decomposition of hydrogen peroxide and sodium perborate in the presence of many ions significantly affects the selectivity. Artemisinin is a natural peroxide that is quite stable in the presence of common ions. In the present study, artemisinin has been exploited for the forensic bloodstain chemiluminescence detection for the first time...
May 11, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28489280/synthesis-and-evaluation-of-cytotoxic-activities-of-artemisinin-derivatives
#16
Qian Sun, Jin Wang, Yao Li, Jingjing Zhuang, Qian Zhang, Xiao Sun, Dequn Sun
Artemisinin is naturally occurring antimalarials which has shown potent anticancer activity. In the present work, a new kind of artemisinin derivatives with piperazino group were synthesized. The cytotoxic activities of derivatives 5a-5d were evaluated by MTT assay against ten cell lines. The result showed that 5a-5d were more effective in inhibiting cancer cells growth than artemisinin. 5d was the most active against HepG2 and PLC-PRF-5 cells, and presented no cytotoxicity on L-02 cells. Hoechst33342 staining and flow cytometry experiment revealed that 5d could induce HepG2 and PLC-PRF-5 cells apoptosis...
May 10, 2017: Chemical Biology & Drug Design
https://www.readbyqxmd.com/read/28487425/a-variant-pfcrt-isoform-can-contribute-to-plasmodium-falciparum-resistance-to-the-first-line-partner-drug-piperaquine
#17
Satish K Dhingra, Devasha Redhi, Jill M Combrinck, Tomas Yeo, John Okombo, Philipp P Henrich, Annie N Cowell, Purva Gupta, Matthew L Stegman, Jonathan M Hoke, Roland A Cooper, Elizabeth Winzeler, Sachel Mok, Timothy J Egan, David A Fidock
Current efforts to reduce the global burden of malaria are threatened by the rapid spread throughout Asia of Plasmodium falciparum resistance to artemisinin-based combination therapies, which includes increasing rates of clinical failure with dihydroartemisinin plus piperaquine (PPQ) in Cambodia. Using zinc finger nuclease-based gene editing, we report that addition of the C101F mutation to the chloroquine (CQ) resistance-conferring PfCRT Dd2 isoform common to Asia can confer PPQ resistance to cultured parasites...
May 9, 2017: MBio
https://www.readbyqxmd.com/read/28480403/fabrication-and-evaluation-of-smart-nanocrystals-of-artemisinin-for-antimalarial-and-antibacterial-efficacy
#18
Syed Muhammad Hassan Shah, Farhat Ullah, Shahzeb Khan, Syed Muhammad Mukarram Shah, Mohamad Isreb
BACKGROUND: Nanocrystals have the potential to substantially increase dissolution rate, solubility with subsequent enhanced bioavailability via the oral route of a range of poor water soluble drugs. Regardless of other issues, scale up of the batch size is the main issue associated with bottom up approach. MATERIAL AND METHODS: Smart nanocrystals of artemisinin (ARM) was produced relatively at large batch sizes (100, 200, 300 and 400ml) compared to our previously reported study by (Shah, et al...
2017: African Journal of Traditional, Complementary, and Alternative Medicines: AJTCAM
https://www.readbyqxmd.com/read/28480232/artemether-lumefantrine-and-dihydroartemisinin-piperaquine-exert-inverse-selective-pressure-on-plasmodium-falciparum-drug-sensitivity-associated-haplotypes-in-uganda
#19
Aimee R Taylor, Jennifer A Flegg, Chris C Holmes, Philippe J Guérin, Carol H Sibley, Melissa D Conrad, Grant Dorsey, Philip J Rosenthal
BACKGROUND: Altered sensitivity to multiple antimalarial drugs is mediated by polymorphisms in pfmdr1, which encodes the Plasmodium falciparum multidrug resistance transporter. In Africa the N86Y and D1246Y polymorphisms have been shown to be selected by treatment, with artemether-lumefantrine (AL) and dihydroartemisinin-piperaquine (DP) selecting for wild-type and mutant alleles, respectively. However, there has been little study of pfmdr1 haplotypes, in part because haplotype analyses are complicated by multiclonal infections...
2017: Open Forum Infectious Diseases
https://www.readbyqxmd.com/read/28479604/codelivery-of-dihydroartemisinin-and-doxorubicin-in-mannosylated-liposomes-for-drug-resistant-colon-cancer-therapy
#20
Xue-Jia Kang, Hui-Yuan Wang, Hui-Ge Peng, Bin-Fan Chen, Wen-Yuan Zhang, Ai-Hua Wu, Qin Xu, Yong-Zhuo Huang
Multidrug resistance (MDR) is a major hurdle in cancer chemotherapy and makes the treatment benefits unsustainable. Combination therapy is a commonly used method for overcoming MDR. In this study we investigated the anti-MDR effect of dihydroartemisinin (DHA), a derivative of artemisinin, in combination with doxorubicin (Dox) in drug-resistant human colon tumor HCT8/ADR cells. We developed a tumor-targeting codelivery system, in which the two drugs were co-encapsulated into the mannosylated liposomes (Man-liposomes)...
May 8, 2017: Acta Pharmacologica Sinica
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