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Shayo EH, Rumisha SF, Mlozi MRS, Bwana VM, Mayala BK, Malima RC, Mlacha T, Mboera LEG. Social determinants of malaria and health care seeking patterns among rice farming and pastoral communities in Kilosa District in central Tanzania. Acta Trop 2015; 144:41-9. [PMID: 25596436 DOI: 10.1016/j.actatropica.2015.01.003] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2014] [Revised: 12/28/2014] [Accepted: 01/07/2015] [Indexed: 11/19/2022]
Abstract
This study was carried out to understand the role social determinants and health seeking behavior among rice farming and pastoral communities in Kilosa District in central Tanzania. The study involved four villages; two with rice farming communities while the other two with pastoral communities. In each village, heads of households or their spouses were interviewed to seek information on livelihoods activities, knowledge and practices on malaria and its preventions. A total of 471 individuals (males=38.9%; females=61.1%) were interviewed. Only 23.5% of the respondents had adequate knowledge on malaria. Fifty-six percent of the respondents could not associate any livelihood activity with malaria transmission. Majority (79%) of the respondents believed that most of fevers were due to malaria; this was higher among the pastoral (81.7%) than rice farming communities (76.1%) (p=0.038). Cases of fever were significantly higher in households with non-educated (31.2%) than educated respondents (21.5%). Women experienced significantly more episodes of fever than men (p<0.001). Of the total of 2606 individuals living in the households, 26.9% were reported to have had fever in the previous three months. Fever was reported more frequently among pastoral than rice farming communities (p<0.01). Of those who had fever, 36.6% were clinically diagnosed with malaria and 22.9% were confirmed to be infected with malaria. A combination of fever+convulsions or joint pains+headache was most frequently perceived to be malaria. Treatment seeking frequency differed by the size of the household and between rice farming and pastoral communities (p=0.05). In conclusion, education, sex, availability of health care facility and livelihood practices were the major social determinants that influence malaria acquisition and care seeking pattern in central Tanzania. Appropriate public health promotion should be designed to address the links of livelihoods and malaria transmission among rural farming communities in an ecohealth approach.
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Affiliation(s)
- Elizabeth H Shayo
- National Institute for Medical Research, P.O. Box 9653, Dar es Salaam, Tanzania
| | - Susan F Rumisha
- National Institute for Medical Research, P.O. Box 9653, Dar es Salaam, Tanzania
| | - Malongo R S Mlozi
- Sokoine University of Agriculture, Chuo Kikuu, P.O. Box 3000, Morogoro, Tanzania
| | - Veneranda M Bwana
- National Institute for Medical Research, Amani Research Centre, P.O. Box 81, Muheza, Tanzania
| | - Benjamin K Mayala
- National Institute for Medical Research, P.O. Box 9653, Dar es Salaam, Tanzania
| | - Robert C Malima
- National Institute for Medical Research, Amani Research Centre, P.O. Box 81, Muheza, Tanzania
| | - Tabitha Mlacha
- National Institute for Medical Research, P.O. Box 9653, Dar es Salaam, Tanzania
| | - Leonard E G Mboera
- National Institute for Medical Research, P.O. Box 9653, Dar es Salaam, Tanzania.
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Wang G, Wormser GP, Zhuge J, Villafuerte P, Ip D, Zeren C, Fallon JT. Utilization of a real-time PCR assay for diagnosis of Babesia microti infection in clinical practice. Ticks Tick Borne Dis 2015; 6:376-82. [PMID: 25819568 DOI: 10.1016/j.ttbdis.2015.03.001] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2014] [Revised: 03/03/2015] [Accepted: 03/03/2015] [Indexed: 10/23/2022]
Abstract
Babesiosis is an emerging tick-borne disease mainly caused Babesia microti, a protozoan that infects erythrocytes. Microscopic examination of blood smears is the current gold standard for detection of Babesia infection, but this diagnostic test has several limitations. We developed and assessed the clinical utilization of a multiplex real-time PCR assay targeting the 18S rRNA gene of B. microti and the human gapdh gene. The limit of detection of this PCR assay was approximately 1-3parasites/μl of blood. The assay showed a diagnostic sensitivity and probable specificity of 100% based on testing 145 retrospective and 185 prospective blood specimens from controls and patients with confirmed babesiosis. Notably, the PCR assay was more sensitive than blood smear examination in patients during and following anti-babesia drug therapy. Our study suggests that PCR testing is as good or better than a blood smear for detection of B. microti in routine clinical practice. PCR testing may confirm the presence of babesiosis in patients whose level of infection is too low for reliable microscopic detection.
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Affiliation(s)
- Guiqing Wang
- Department of Pathology, New York Medical College, Valhalla, NY, United States; Department of Pathology and Clinical Laboratories, Westchester Medical Center, Valhalla, NY, United States.
| | - Gary P Wormser
- Department of Medicine, New York Medical College, Valhalla, NY, United States
| | - Jian Zhuge
- Department of Pathology and Clinical Laboratories, Westchester Medical Center, Valhalla, NY, United States
| | - Patrick Villafuerte
- Department of Medicine, New York Medical College, Valhalla, NY, United States
| | - Dawn Ip
- Department of Pathology and Clinical Laboratories, Westchester Medical Center, Valhalla, NY, United States
| | - Christine Zeren
- Department of Pathology and Clinical Laboratories, Westchester Medical Center, Valhalla, NY, United States
| | - John T Fallon
- Department of Pathology, New York Medical College, Valhalla, NY, United States; Department of Medicine, New York Medical College, Valhalla, NY, United States; Department of Pathology and Clinical Laboratories, Westchester Medical Center, Valhalla, NY, United States
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53
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Pandey P, Singh S, Tewari N, Srinivas K, Shukla A, Gupta N, Vasudev PG, Khan F, Pal A, Bhakuni RS, Tandon S, Kumar JK, Banerjee S. Hairy root mediated functional derivatization of artemisinin and their bioactivity analysis. ACTA ACUST UNITED AC 2015. [DOI: 10.1016/j.molcatb.2015.01.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Miranda TA, Silva PHR, Pianetti GA, César IC. Simultaneous quantitation of chloroquine and primaquine by UPLC-DAD and comparison with a HPLC-DAD method. Malar J 2015; 14:29. [PMID: 25626728 PMCID: PMC4318193 DOI: 10.1186/s12936-015-0570-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2014] [Accepted: 01/17/2015] [Indexed: 12/04/2022] Open
Abstract
Background Chloroquine and primaquine are the first-line treatment recommended by World Health Organization for malaria caused by Plasmodium vivax. Since the problem of counterfeit or substandard anti-malarials is well established all over the world, the development of rapid and reliable methods for quality control analysis of these drugs is essential. Thus, the aim of this study was to develop and validate a novel UPLC-DAD method for simultaneously quantifying chloroquine and primaquine in tablet formulations. Methods The UPLC separation was carried out using a Hypersil C18 column (50 × 2.1 mm id; 1.9 μm particle size) and a mobile phase composed of acetonitrile (A) and 0.1% aqueous triethylamine, pH 3.0 adjusted with phosphoric acid (B), at a flow rate 0.6 mL/min. Gradient elution was employed. UV detection was performed at 260 nm. UPLC method was fully validated and the results were compared to a conventional HPLC-DAD method for the analysis of chloroquine and primaquine in tablet formulations. Results UPLC method was shown to be linear (r2 > 0.99), precise (CV < 2.0%), accurate (recovery rates from 98.11 to 99.83%), specific, and robust. No significant differences were observed between the chloroquine and primaquine contents obtained by UPLC and HPLC methods. However, UPLC method promoted faster analyses, better chromatographic performance and lower solvent consumption. Conclusions The developed UPLC method was shown to be a rapid and suitable technique to quantify chloroquine and primaquine in pharmaceutical preparations and may be successfully employed for quality control analysis.
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Affiliation(s)
| | | | | | - Isabela C César
- Departamento de Produtos Farmacêuticos, Faculdade de Farmácia, Universidade Federal de Minas Gerais, Av Pres Antônio Carlos 6627, Belo Horizonte, 31270-901, MG, Brazil.
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55
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Vullo D, Del Prete S, Fisher GM, Andrews KT, Poulsen SA, Capasso C, Supuran CT. Sulfonamide inhibition studies of the η-class carbonic anhydrase from the malaria pathogen Plasmodium falciparum. Bioorg Med Chem 2014; 23:526-31. [PMID: 25533402 DOI: 10.1016/j.bmc.2014.12.009] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2014] [Revised: 12/01/2014] [Accepted: 12/04/2014] [Indexed: 12/12/2022]
Abstract
The η-carbonic anhydrases (CAs, EC 4.2.1.1) were recently discovered as the sixth genetic class of this metalloenzyme superfamily, and are so far known only in protozoa, including various Plasmodium species, the causative agents of malaria. We report here an inhibition study of the η-CA from Plasmodium falciparum (PfCA) against a panel of sulfonamides and one sulfamate compound, some of which are clinically used. The strongest inhibitors identified were ethoxzolamide and sulthiame, with KIs of 131-132 nM, followed by acetazolamide, methazolamide and hydrochlorothiazide (KIs of 153-198 nM). Brinzolamide, topiramate, zonisamide, indisulam, valdecoxib and celecoxib also showed significant inhibitory action against PfCA, with KIs ranging from 217 to 308 nM. An interesting observation was that the more efficient PfCA inhibitors are representative of several scaffolds and chemical classes, including benzene sulfonamides, monocyclic/bicyclic heterocyclic sulfonamides and compounds with a more complex scaffold (i.e., the sugar sulfamate derivative, topiramate, and the coxibs, celecoxib and valdecoxib). A comprehensive inhibition study of small molecules for η-CAs is needed as a first step towards assessing PfCA as a druggable target. The present work identifies the first known η-CA inhibitors and provides a platform for the development of next generation novel PfCA inhibitors.
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Affiliation(s)
- Daniela Vullo
- Università degli Studi di Firenze, Polo Scientifico, Laboratorio di Chimica Bioinorganica, Rm. 188, Via della Lastruccia 3, 50019 Sesto Fiorentino, Florence, Italy
| | - Sonia Del Prete
- Istituto di Bioscienze e Biorisorse (IBBR)-CNR, Via P. Castellino 111, 80131 Napoli, Italy
| | - Gillian M Fisher
- Eskitis Institute for Drug Discovery, Griffith University, Nathan, Queensland 4111, Australia
| | - Katherine T Andrews
- Eskitis Institute for Drug Discovery, Griffith University, Nathan, Queensland 4111, Australia
| | - Sally-Ann Poulsen
- Eskitis Institute for Drug Discovery, Griffith University, Nathan, Queensland 4111, Australia
| | - Clemente Capasso
- Istituto di Bioscienze e Biorisorse (IBBR)-CNR, Via P. Castellino 111, 80131 Napoli, Italy.
| | - Claudiu T Supuran
- Università degli Studi di Firenze, Polo Scientifico, Laboratorio di Chimica Bioinorganica, Rm. 188, Via della Lastruccia 3, 50019 Sesto Fiorentino, Florence, Italy; Università degli Studi di Firenze, Dipartimento Neurofarba, Sezione di Scienze Farmaceutiche, Polo Scientifico, Sesto Fiorentino, Firenze, Italy.
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Feleke SM, Animut A, Belay M. Prevalence of malaria among acute febrile patients clinically suspected of having malaria in the Zeway Health Center, Ethiopia. Jpn J Infect Dis 2014; 68:55-9. [PMID: 25420658 DOI: 10.7883/yoken.jjid.2013.062] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Malaria diagnosis is a common challenge in developing countries with limited diagnostic services. Common febrile illnesses were assessed in 280 malaria-suspected patients, and each case was subjected to clinical and laboratory examinations for malaria, relapsing fever, typhoid fever, typhus, and brucellosis. Data were entered and analyzed using Epi Info version 3.1 software. Malaria accounted for 17% (CI, 12.6-21.4%) of febrile illnesses. The remaining cases were associated with typhoid fever (18.5%; CI, 13.95-23.05%), typhus (17.8%; CI, 13.32-22.28%), brucellosis (1%; CI, -0.17-2.17%), relapsing fever (2%; CI, 0.36-3.64%), and unknown causes (44%). Approximately 7% of patients had coinfections, and 2% of patients treated as monoinfections. Approximately 1.4% of the nonmalarial patients received antimalarial treatment. The sensitivity and specificity of the CareStart Pf/pan rapid diagnostic tests in comparison with those of microscopy were 100% and 91%, respectively, with positive- and negative-predictive values of 94% and 100%, respectively. Compared with microscopy, the positive-predictive value of each malaria symptom was much lower than that of the symptoms combined: fever, 17%; sweating, 30%; headache, 18%; general body ache, 22%; loss of appetite, 21%. The study findings revealed a high proportion of nonmalarial illnesses were clinically categorized as malaria. Parasite-based diagnosis is recommended for the management of malarial and nonmalarial cases.
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Kaddumukasa M, Buwembo W, Sekikubo M, Naiwumbwe H, Namusoke F, Kiwuwa S, Oketch B, Noor R, Chilengi R, Mworozi E, Kironde F. Malariometric indices from Iganga, Uganda: baseline characterization in preparation of GMZ2 vaccine trial. BMC Res Notes 2014; 7:793. [PMID: 25380673 PMCID: PMC4232662 DOI: 10.1186/1756-0500-7-793] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2013] [Accepted: 10/14/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Malaria still remains the leading cause of childhood morbidity and mortality in Uganda. Interventions like malaria vaccines which reduce the malaria burden are needed in malaria endemic communities. There is need to establish baseline characteristics in vaccine trial study sites. This study determined the following baseline malariometric indices: spleen rates, bed net use, malaria parasitaemia and malaria episodes in an inception cohort of children aged 12 - 60 months in Iganga district, Uganda. METHODS In a longitudinal cohort study, 748 children were enrolled with 397 in an active follow up arm and 351 in a passive arm. The children in the two arms were followed for 6 months to determine the incidence of malaria episodes. RESULTS The overall baseline spleen rate was 8.2% (61/748) among the study participants. Of the households surveyed, about 36% reported using bed nets and almost 30% of the users had insecticide-treated nets. 274 (36.6%) of the study participants had a history of fever in the past 24 hrs at the time of the baseline survey. All participants had a peripheral blood smear for malaria parasites done at enrollment with 76.8% having the asexual form of malaria parasites. The malaria episodes per child per year were 1.5 and 0.79 in the active and passive follow up arms respectively. CONCLUSIONS There is a high prevalence of malaria asexual parasitaemia in children below five years. The bed net usage still remains low among this population. These baseline malariometric indices have important implication for malaria control interventions.
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Affiliation(s)
| | - William Buwembo
- Makerere University College of Health Sciences, Kampala, Uganda.
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58
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Kinfe HH, Moshapo PT, Makolo FL, Gammon DW, Ehlers M, Schmuck C. Preparation and antimalarial activity of a novel class of carbohydrate-derived, fused thiochromans. Eur J Med Chem 2014; 87:197-202. [DOI: 10.1016/j.ejmech.2014.09.060] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2014] [Revised: 08/23/2014] [Accepted: 09/17/2014] [Indexed: 01/01/2023]
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Kronenberger T, Lunev S, Wrenger C, Groves MR. Purification, crystallization and preliminary X-ray diffraction analysis of pyridoxal kinase from Plasmodium falciparum (PfPdxK). ACTA CRYSTALLOGRAPHICA SECTION F-STRUCTURAL BIOLOGY COMMUNICATIONS 2014; 70:1550-5. [PMID: 25372829 DOI: 10.1107/s2053230x14019864] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2014] [Accepted: 09/02/2014] [Indexed: 11/10/2022]
Abstract
Pyridoxal kinases (PdxK) catalyze the phosphorylation of vitamin B6 precursors. Thus, these enzymes are an essential part of many metabolic processes in all organisms. The protozoan parasite Plasmodium falciparum (the main causative agent of Malaria tropica) possesses a unique de novo B6-biosynthesis pathway in addition to a interconversion pathway based on the activity of plasmodial PdxK (PfPdxK). The role of PdxK in B6 salvage has prompted previous authors to suggest PdxK as a promising target for structure-based antimalarial drug design. Here, the expression, purification, crystallization and preliminary X-ray diffraction analysis of PfPdxK are reported. PfPdxK crystals have been grown in space group P2₁, with unit-cell parameters a=52.7, b=62.0, c=93.7 Å, β=95°. A data set has been collected to 2 Å resolution and an initial molecular-replacement solution is described.
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Affiliation(s)
- Thales Kronenberger
- Unit for Drug Discovery, Department of Parasitology, Institute of Biomedical Sciences, University of Saõ Paulo, Avenida Professor Lineu Prestes 1374, Saõ Paulo-SP 05508-000, Brazil
| | - Sergey Lunev
- Department of Drug Design, Groningen Research Institute of Pharmacy (GRIP), Rijksuniversiteit Groningen (RUG), Antonius Deusinglaan 1, 9713 AV Groningen, The Netherlands
| | - Carsten Wrenger
- Unit for Drug Discovery, Department of Parasitology, Institute of Biomedical Sciences, University of Saõ Paulo, Avenida Professor Lineu Prestes 1374, Saõ Paulo-SP 05508-000, Brazil
| | - Matthew R Groves
- Department of Drug Design, Groningen Research Institute of Pharmacy (GRIP), Rijksuniversiteit Groningen (RUG), Antonius Deusinglaan 1, 9713 AV Groningen, The Netherlands
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High-throughput tri-colour flow cytometry technique to assess Plasmodium falciparum parasitaemia in bioassays. Malar J 2014; 13:412. [PMID: 25331683 PMCID: PMC4213491 DOI: 10.1186/1475-2875-13-412] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2014] [Accepted: 10/09/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Unbiased flow cytometry-based methods have become the technique of choice in many laboratories for high-throughput, accurate assessments of malaria parasites in bioassays. A method to quantify live parasites based on mitotracker red CMXRos was recently described but consistent distinction of early ring stages of Plasmodium falciparum from uninfected red blood cells (uRBC) remains a challenge. METHODS Here, a high-throughput, three-parameter (tri-colour) flow cytometry technique based on mitotracker red dye, the nucleic acid dye coriphosphine O (CPO) and the leucocyte marker CD45 for enumerating live parasites in bioassays was developed. The technique was applied to estimate the specific growth inhibition index (SGI) in the antibody-dependent cellular inhibition (ADCI) assay and compared to parasite quantification by microscopy and mitotracker red staining. The Bland-Altman analysis was used to compare biases between SGI estimated by the tri-colour staining technique, mitotracker red and by microscopy. RESULTS CPO allowed a better separation between early rings and uRBCs compared to mitotracker red resulting in a more accurate estimate of total parasitaemia. The tri-colour technique is rapid, cost effective and robust with comparable sensitivity to microscopy and capable of discriminating between live and dead and/or compromised parasites. Staining for CD45 improved parasitaemia estimates in ADCI assay since high numbers of leucocytes interfered with the accurate identification of parasitized RBC. The least bias (-1.60) in SGI was observed between the tri-colour and microscopy. CONCLUSION An improved methodology for high-throughput assessment of P. falciparum parasitaemia under culture conditions that could be useful in different bioassays, including ADCI and growth inhibition assays has been developed.
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Imprasittichail W, Roytrakul S, Krungkrai SR, Krungkrail J. A unique insertion of low complexity amino acid sequence underlies protein-protein interaction in human malaria parasite orotate phosphoribosyltransferase and orotidine 5'-monophosphate decarboxylase. ASIAN PAC J TROP MED 2014; 7:184-92. [PMID: 24507637 DOI: 10.1016/s1995-7645(14)60018-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2013] [Revised: 09/15/2013] [Accepted: 01/15/2014] [Indexed: 11/17/2022] Open
Abstract
OBJECTIVE To investigate the multienzyme complex formation of human malaria parasite Plasmodium falciparum (P. falciparum) orotate phosphoribosyltransferase (OPRT) and orotidine 5'-monophosphate decarboxylase (OMPDC), the fifth and sixth enzyme of the de novo pyrimidine biosynthetic pathway. Previously, we have clearly established that the two enzymes in the malaria parasite exist physically as a heterotetrameric (OPRT)2(OMPDC)2 complex containing two subunits each of OPRT and OMPDC, and that the complex have catalytic kinetic advantages over the monofunctional enzyme. METHODS Both enzymes were cloned and expressed as recombinant proteins. The protein-protein interaction in the enzyme complex was identified using bifunctional chemical cross-linker, liquid chromatography-mass spectrometric analysis and homology modeling. RESULTS The unique insertions of low complexity region at the α 2 and α 5 helices of the parasite OMPDC, characterized by single amino acid repeat sequence which was not found in homologous proteins from other organisms, was located on the OPRT-OMPDC interface. The structural models for the protein-protein interaction of the heterotetrameric (OPRT)2(OMPDC)2 multienzyme complex were proposed. CONCLUSIONS Based on the proteomic data and structural modeling, it is surmised that the human malaria parasite low complexity region is responsible for the OPRT-OMPDC interaction. The structural complex of the parasite enzymes, thus, represents an efficient functional kinetic advantage, which in line with co-localization principles of evolutional origin, and allosteric control in protein-protein-interactions.
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Affiliation(s)
- Waranya Imprasittichail
- Department of Biochemistry, Faculty of Medicine, Chulalongkorn University, Bangkok 10330, Thailand
| | - Sittiruk Roytrakul
- National Center for Genetic Engineering and Biotechnology, Pathumthani 12120, Thailand
| | - Sudaratana R Krungkrai
- Unit of Biochemistry, Department of Medical Science, Faculty of Science, Rangsit University, Pathumthani 12000, Thailand
| | - Jerapan Krungkrail
- Department of Biochemistry, Faculty of Medicine, Chulalongkorn University, Bangkok 10330, Thailand.
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Miller AK, Harrell E, Ye L, Baptiste-Brown S, Kleim JP, Ohrt C, Duparc S, Möhrle JJ, Webster A, Stinnett S, Hughes A, Griffith S, Beelen AP. Pharmacokinetic interactions and safety evaluations of coadministered tafenoquine and chloroquine in healthy subjects. Br J Clin Pharmacol 2014; 76:858-67. [PMID: 23701202 DOI: 10.1111/bcp.12160] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2012] [Accepted: 05/09/2013] [Indexed: 11/28/2022] Open
Abstract
AIMS The long-acting 8-aminoquinoline tafenoquine (TQ) coadministered with chloroquine (CQ) may radically cure Plasmodium vivax malaria. Coadministration therapy was evaluated for a pharmacokinetic interaction and for pharmacodynamic, safety and tolerability characteristics. METHODS Healthy subjects, 18-55 years old, without documented glucose-6-phosphate dehydrogenase deficiency, received CQ alone (days 1-2, 600 mg; and day 3, 300 mg), TQ alone (days 2 and 3, 450 mg) or coadministration therapy (day 1, CQ 600 mg; day 2, CQ 600 mg + TQ 450 mg; and day 3, CQ 300 mg + TQ 450 mg) in a randomized, double-blind, parallel-group study. Blood samples for pharmacokinetic and pharmacodynamic analyses and safety data, including electrocardiograms, were collected for 56 days. RESULTS The coadministration of CQ + TQ had no effect on TQ AUC0-t , AUC0-∞ , Tmax or t1/2 . The 90% confidence intervals of CQ + TQ vs. TQ for AUC0-t , AUC0-∞ and t1/2 indicated no drug interaction. On day 2 of CQ + TQ coadministration, TQ Cmax and AUC0-24 increased by 38% (90% confidence interval 1.27, 1.64) and 24% (90% confidence interval 1.04, 1.46), respectively. The pharmacokinetics of CQ and its primary metabolite desethylchloroquine were not affected by TQ. Coadministration had no clinically significant effect on QT intervals and was well tolerated. CONCLUSIONS No clinically significant safety or pharmacokinetic/pharmacodynamic interactions were observed with coadministered CQ and TQ in healthy subjects.
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Fridley GE, Le H, Yager P. Highly sensitive immunoassay based on controlled rehydration of patterned reagents in a 2-dimensional paper network. Anal Chem 2014; 86:6447-53. [PMID: 24882058 PMCID: PMC4082385 DOI: 10.1021/ac500872j] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2014] [Accepted: 05/31/2014] [Indexed: 11/28/2022]
Abstract
We have demonstrated a multistep 2-dimensional paper network immunoassay based on controlled rehydration of patterned, dried reagents. Previous work has shown that signal enhancement improves the limit of detection in 2-dimensional paper network assays, but until now, reagents have only been included as wet or dried in separate conjugate pads placed at the upstream end of the assay device. Wet reagents are not ideal for point-of-care because they must be refrigerated and typically limit automation and require more user steps. Conjugate pads allow drying but do not offer any control of the reagent distribution upon rehydration and can be a source of error when pads do not contact the assay membrane uniformly. Furthermore, each reagent is dried on a separate pad, increasing the fabrication complexity when implementing multistep assays that require several different reagents. Conversely, our novel method allows for consistent, controlled rehydration from patterned reagent storage depots directly within the paper membrane. In this assay demonstration, four separate reagents were patterned in different regions of the assay device: a gold-antibody conjugate used for antigen detection and three different signal enhancement components that must not be mixed until immediately before use. To show the viability of patterning and drying reagents directly onto a paper device for dry reagent storage and subsequent controlled release, we tested this device with the malaria antigen Plasmodium falciparum histidine-rich protein 2 (PfHRP2) as an example of target analyte. In this demonstration, the signal enhancement step increases the visible signal by roughly 3-fold and decreases the analytical limit of detection by 2.75-fold.
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Affiliation(s)
- Gina E. Fridley
- University of Washington, Department of Bioengineering, Box 355061, Seattle, Washington 98195, United States
| | - Huy Le
- University of Washington, Department of Bioengineering, Box 355061, Seattle, Washington 98195, United States
| | - Paul Yager
- University of Washington, Department of Bioengineering, Box 355061, Seattle, Washington 98195, United States
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Falodun A, Imieje V, Erharuyi O, Ahomafor J, Jacob MR, Khan SI, Hamann MT. Evaluation of three medicinal plant extracts against Plasmodium falciparum and selected microganisms. AFRICAN JOURNAL OF TRADITIONAL, COMPLEMENTARY, AND ALTERNATIVE MEDICINES : AJTCAM 2014; 11:142-6. [PMID: 25392594 PMCID: PMC4202410 DOI: 10.4314/ajtcam.v11i4.22] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
BACKGROUND A great revival of scientific interests in drug discovery has been witnessed in recent years from medicinal plants for health maintenance. The aim of this work was to investigate three Nigerian medicinal plants collected in Nigeria for their in vitro antiplasmodial and antimicrobial activities. MATERIALS AND METHODS Extracts obtained from parts of Persea americana, Jatropha podagrica and Picralima nitida and their fractions were evaluated for in vitro antiprotozoal and antimicrobial activity. RESULT The methanol extract of P. nitida demonstrated activity against chloroquine-sensitive and chloroquine-resistant P. falciparum clones with IC50 values of 6.3 and 6.0 µg/mL, respectively. Methanol and chloroform extracts of P. americana seed showed antifungal activity against Cryptococcus neoformans IC50 less than 8 and 8.211 µg/mL respectively. Finally, the petroleum ether extract of P. americana had activity against methicillin-resistant Staphylococcus aureus (MRSA) with an IC50 value of 8.7 µg/mL. CONCLUSION The study revealed the antibacterial and antiplasmodial activities of the plants extracts at the tested concentrations.
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Affiliation(s)
- Abiodun Falodun
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, University of Benin, Benin City, Nigeria ; Department of Pharmacognosy, School of Pharmacy, University, University of Mississippi, MS 38655, USA
| | - Vincent Imieje
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, University of Benin, Benin City, Nigeria ; Institute of Organic Chemistry, University of Restock, 18509, Restock, Germany
| | - Osayewenre Erharuyi
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, University of Benin, Benin City, Nigeria ; Institute of Organic Chemistry, University of Restock, 18509, Restock, Germany
| | - Joy Ahomafor
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, University of Benin, Benin City, Nigeria
| | - Melissa R Jacob
- Center for for Natural Products Research, School of Pharmacy, University of Mississippi, MS, 38677, USA
| | - Shabana I Khan
- Center for for Natural Products Research, School of Pharmacy, University of Mississippi, MS, 38677, USA
| | - Mark T Hamann
- Department of Pharmacognosy, School of Pharmacy, University, University of Mississippi, MS 38655, USA
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Kaushal NA, Kaushal DC. Production and characterization of monoclonal antibodies against substrate specific loop region ofPlasmodium falciparumlactate dehydrogenase. Immunol Invest 2014; 43:556-71. [DOI: 10.3109/08820139.2014.892962] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Comparison of microscopy, nested-PCR, and Real-Time-PCR assays using high-throughput screening of pooled samples for diagnosis of malaria in asymptomatic carriers from areas of endemicity in Myanmar. J Clin Microbiol 2014; 52:1838-45. [PMID: 24648557 DOI: 10.1128/jcm.03615-13] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Asymptomatic infection is an important obstacle for controlling disease in countries where malaria is endemic. Because asymptomatic carriers do not seek treatment for their infections, they can have high levels of gametocytes and constitute a reservoir available for new infection. We employed a sample pooling/PCR-based molecular detection strategy for screening malaria infection in residents from areas of Myanmar where malaria is endemic. Blood samples (n = 1,552) were collected from residents in three areas of malaria endemicity (Kayin State, Bago, and Tanintharyi regions) of Myanmar. Two nested PCR and real-time PCR assays showed that asymptomatic infection was detected in about 1.0% to 9.4% of residents from the surveyed areas. The sensitivities of the two nested PCR and real-time PCR techniques were higher than that of microscopy examination (sensitivity, 100% versus 26.4%; kappa values, 0.2 to 0.5). Among the three regions, parasite-positive samples were highly detected in subjects from the Bago and Tanintharyi regions. Active surveillance of residents from regions of intense malaria transmission would reduce the risk of morbidity and mitigate transmission to the population in these areas of endemicity. Our data demonstrate that PCR-based molecular techniques are more efficient than microscopy for nationwide surveillance of malaria in countries where malaria is endemic.
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Synthesis and study of cytotoxic activity of 1,2,4-trioxane- and egonol-derived hybrid molecules against Plasmodium falciparum and multidrug-resistant human leukemia cells. Eur J Med Chem 2014; 75:403-12. [DOI: 10.1016/j.ejmech.2014.01.043] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2013] [Revised: 01/17/2014] [Accepted: 01/19/2014] [Indexed: 01/09/2023]
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de Freitas DRC, Gomes LT, Fontes CJF, Tauil PL, Pang LW, Duarte EC. Sensitivity of nested-PCR for plasmodium detection in pooled whole blood samples and its usefulness to blood donor screening in endemic areas. Transfus Apher Sci 2014; 50:242-6. [PMID: 24508148 DOI: 10.1016/j.transci.2014.01.016] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2013] [Revised: 01/07/2014] [Accepted: 01/11/2014] [Indexed: 10/25/2022]
Abstract
Transfusion-transmitted malaria is a severe disease with high fatality rate. Most Brazilian blood banks in the Amazon region perform malaria screening using microscopic examination (thick smears). Since low parasite concentrations are expected in asymptomatic blood donors a high sensitivity test should be used for donor screening. This study determined the sensitivity of a nested-PCR for plasmodium detection in pooled samples. We performed a one-stage criterion validation study with 21 positive samples pooled with samples from ten negative volunteer until three different concentrations were reached (0.33; 0.25; 0.20 parasites/μL - p/μL). Nested PCR was performed as described by Snounou et al. (1993). Sensitivities (and confidence intervals) were determined by stratum of final parasite concentration on the pooled samples. All samples with parasitemia values of 0.33 and 0.25 p/μL had 100% sensitivity (95%CI=86.3-100). One negative result was obtained from a sample with 0.20 p/μL sensitivity=95.2% (95%CI=76.2-99.9). Compared to parasitemia detectable under ideal conditions of thick smear, this nested-PCR in pooled sample was able to detect 40 times more parasites per microliter. Nested-PCR in pooled samples should be considered as a high sensitive alternative to thick smear for donor screening in blood banks at endemic regions. Local authorities need to assess cost:benefit advantages of this method compared to alternatives.
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Affiliation(s)
- Daniel Roberto Coradi de Freitas
- Tropical Medicine Center, Universidade de Brasília, Brasília, DF, Brazil; National Agency for Health Surveillance (Anvisa), Brazil.
| | | | | | - Pedro Luiz Tauil
- Tropical Medicine Center, Universidade de Brasília, Brasília, DF, Brazil
| | - Lorrin W Pang
- Tropical Medicine Center, Universidade de Brasília, Brasília, DF, Brazil
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Zhang Y, Evans GB, Clinch K, Crump DR, Harris LD, Fröhlich RFG, Tyler PC, Hazleton KZ, Cassera MB, Schramm VL. Transition state analogues of Plasmodium falciparum and human orotate phosphoribosyltransferases. J Biol Chem 2013; 288:34746-54. [PMID: 24158442 DOI: 10.1074/jbc.m113.521955] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
The survival and proliferation of Plasmodium falciparum parasites and human cancer cells require de novo pyrimidine synthesis to supply RNA and DNA precursors. Orotate phosphoribosyltransferase (OPRT) is an indispensible component in this metabolic pathway and is a target for antimalarials and antitumor drugs. P. falciparum (Pf) and Homo sapiens (Hs) OPRTs are characterized by highly dissociative transition states with ribocation character. On the basis of the geometrical and electrostatic features of the PfOPRT and HsOPRT transition states, analogues were designed, synthesized, and tested as inhibitors. Iminoribitol mimics of the ribocation transition state in linkage to pyrimidine mimics using methylene or ethylene linkers gave dissociation constants (Kd) as low as 80 nM. Inhibitors with pyrrolidine groups as ribocation mimics displayed slightly weaker binding affinities for OPRTs. Interestingly, p-nitrophenyl riboside 5'-phosphate bound to OPRTs with Kd values near 40 nM. Analogues designed with a C5-pyrimidine carbon-carbon bond to ribocation mimics gave Kd values in the range of 80-500 nM. Acyclic inhibitors with achiral serinol groups as the ribocation mimics also displayed nanomolar inhibition against OPRTs. In comparison with the nucleoside derivatives, inhibition constants of their corresponding 5'-phosphorylated transition state analogues are largely unchanged, an unusual property for a nucleotide-binding site. In silico docking of the best inhibitor into the HsOPRT active site supported an extensive hydrogen bond network associated with the tight binding affinity. These OPRT transition state analogues identify crucial components of potent inhibitors targeting OPRT enzymes. Despite their tight binding to the targets, the inhibitors did not kill cultured P. falciparum.
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Affiliation(s)
- Yong Zhang
- From the Department of Biochemistry, Albert Einstein College of Medicine, Bronx, New York 10461 and
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70
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Matrangolo FS, Liarte DB, Andrade LC, de Melo MF, Andrade JM, Ferreira RF, Santiago AS, Pirovani CP, Silva-Pereira RA, Murta SM. Comparative proteomic analysis of antimony-resistant and -susceptible Leishmania braziliensis and Leishmania infantum chagasi lines. Mol Biochem Parasitol 2013; 190:63-75. [DOI: 10.1016/j.molbiopara.2013.06.006] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2012] [Revised: 06/19/2013] [Accepted: 06/24/2013] [Indexed: 10/26/2022]
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Njau JD, Stephenson R, Menon M, Kachur SP, McFarland DA. Exploring the impact of targeted distribution of free bed nets on households bed net ownership, socio-economic disparities and childhood malaria infection rates: analysis of national malaria survey data from three sub-Saharan Africa countries. Malar J 2013; 12:245. [PMID: 23855893 PMCID: PMC3720242 DOI: 10.1186/1475-2875-12-245] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2013] [Accepted: 06/26/2013] [Indexed: 11/17/2022] Open
Abstract
Background The last decade has witnessed increased funding for malaria control. Malaria experts have used the opportunity to advocate for rollout of such interventions as free bed nets. A free bed net distribution strategy is seen as the quickest way to improve coverage of effective malaria control tools especially among poorest communities. Evidence to support this claim is however, sparse. This study explored the effectiveness of targeted free bed net distribution strategy in achieving equity in terms of ownership and use of bed nets and also reduction of malaria prevalence among children under-five years of age. Methods National malaria indicator survey (MIS) data from Angola, Tanzania and Uganda was used in the analysis. Hierarchical multilevel logistic regression models were used to analyse the relationship between variables of interest. Outcome variables were defined as: childhood test-confirmed malaria infections, household ownership of any mosquito net and children’s use of any mosquito nets. Marginal effects of having free bed net distribution on households with different wealth status were calculated. Results Angolan children from wealthier households were 6.4 percentage points less likely to be parasitaemic than those in poorest households, whereas those from Tanzania and Uganda were less likely to test malaria positive by 7 and 11.6 percentage points respectively (p < 0.001). The study estimates and present results on the marginal effects based on the impact of free bed net distribution on children's malaria status given their socio-economic background. Poorest households were less likely to own a net by 21.4% in Tanzania, and 2.8% in Uganda, whereas both poorer and wealthier Angolan households almost achieved parity in bed net ownership (p < 0.001). Wealthier households had a higher margin of using nets than poorest people in both Tanzania and Uganda by 11.4% and 3.9% respectively. However, the poorest household in Angola had a 6.1% net use advantage over children in wealthier households (p < 0.001). Conclusion This is the first study to use nationally representative data to explore inequalities in bed net ownership and related consequences on childhood malaria infection rates across different countries. While targeted distribution of free bed nets improved overall bed net ownership, it did not overcome ownership inequalities as measured by household socioeconomic status. Use of bed nets was disproportionately lower among poorest children, except for Angola where bed net use was higher among poorest households when compared to children in wealthier households. The study highlights the need for malaria control world governing bodies and policy makers to continue working on finding appropriate strategies to improve access to effective malaria control tools especially by the poorest who often times bears the brunt of malaria burden than their wealthier counterparts.
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Affiliation(s)
- Joseph D Njau
- Department of Health Policy & Management, Rollins School of Public Health (RSPH) of Emory University, 1518 Clifton Rd 16NE, Atlanta, GA 30322, USA.
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Dolabela MF, Oliveira SG, Peres JM, Nascimento JMS, Póvoa MM, Oliveira AB. In vitro antimalarial activity of six Aspidosperma species from the state of Minas Gerais (Brazil). AN ACAD BRAS CIENC 2013. [PMID: 23207699 DOI: 10.1590/s0001-37652012000400005] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Ethnomedicinal informations point to some Aspidosperma species (Apocynaceae) as antimalarial plants in Brazil and have motivated the evaluation of six species which were collected in the state of Minas Gerais: A. cylindrocarpon Müll. Arg., A. parvifolium A. DC., A. olivaceum Müll. Arg., A. ramiflorum Müll. Arg., A. spruceanum Benth. ex Müll. Arg. and A. tomentosum Mart.. A total of 23 extracts of different plant parts in different solvents were assayed in vitro against chloroquine-resistant (W2) and chloroquine-sensitive (3D7) strains of Plasmodium falciparum. All the extracts were shown to be active with IC50 values in the range of 5.0 ± 0 2.8 µg/mL to 65.0 ± 4.2 µg/mL. TLC profile of the extracts revealed the presence of alkaloids in the six species assayed. These results seem to confirm the popular use of Aspidosperma species to treat human malaria in Brazil and seem point to alkaloids as the putative active compounds of the assayed species.
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73
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The correlation between electronic structure and antimalarial activity of alkoxylated and hydroxylated chalcones. Med Chem Res 2013. [DOI: 10.1007/s00044-013-0667-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Harvey SA, Paredes Olórtegui M, Leontsini E, Ramal Asayag C, Scott K, Winch PJ. Trials of improved practices (TIPs): a strategy for making long-lasting nets last longer? Am J Trop Med Hyg 2013; 88:1109-15. [PMID: 23530074 DOI: 10.4269/ajtmh.12-0641] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Long-lasting insecticidal net (LLIN) use is a proven malaria prevention method. Mass distribution has greatly expanded LLIN access in sub-Saharan Africa, but a gap remains between LLIN ownership and use. Furthermore, LLINs wear out more quickly than anticipated. This paper suggests a participatory research strategy-trials of improved practices (TIPs)-that could identify locally appropriate approaches to prolonging net life and increasing effective use. We used TIPs to overcome barriers to optimal net use in the Peruvian Amazon. Working with 15 families in three villages, we tested home treatment of cotton nets, use of an alternative netting fabric, and alternative washing and care instructions. TIPs helped confirm feasibility of these interventions. Although our findings are time- and context-specific, TIPs could help improve consistency and effectiveness of current LLIN use and prolong net lifespan in sub-Saharan Africa and elsewhere. This would help maximize the value of shrinking donor resources for malaria.
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Affiliation(s)
- Steven A Harvey
- Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205, USA.
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Comparison of PfHRP-2/pLDH ELISA, qPCR and microscopy for the detection of plasmodium events and prediction of sick visits during a malaria vaccine study. PLoS One 2013; 8:e56828. [PMID: 23554856 PMCID: PMC3598859 DOI: 10.1371/journal.pone.0056828] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2012] [Accepted: 01/15/2013] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Compared to expert malaria microscopy, malaria biomarkers such as Plasmodium falciparum histidine rich protein-2 (PfHRP-2), and PCR provide superior analytical sensitivity and specificity for quantifying malaria parasites infections. This study reports on parasite prevalence, sick visits parasite density and species composition by different diagnostic methods during a phase-I malaria vaccine trial. METHODS Blood samples for microscopy, PfHRP-2 and Plasmodium lactate dehydrogenase (pLDH) ELISAs and real time quantitative PCR (qPCR) were collected during scheduled (n = 298) or sick visits (n = 38) from 30 adults participating in a 112-day vaccine trial. The four methods were used to assess parasite prevalence, as well as parasite density over a 42-day period for patients with clinical episodes. RESULTS During scheduled visits, qPCR (39.9%, N = 119) and PfHRP-2 ELISA (36.9%, N = 110) detected higher parasite prevalence than pLDH ELISA (16.8%, N = 50) and all methods were more sensitive than microscopy (13.4%, N = 40). All microscopically detected infections contained P. falciparum, as mono-infections (95%) or with P. malariae (5%). By qPCR, 102/119 infections were speciated. P. falciparum predominated either as monoinfections (71.6%), with P. malariae (8.8%), P. ovale (4.9%) or both (3.9%). P. malariae (6.9%) and P. ovale (1.0%) also occurred as co-infections (2.9%). As expected, higher prevalences were detected during sick visits, with prevalences of 65.8% (qPCR), 60.5% (PfHRP-2 ELISA), 21.1% (pLDH ELISA) and 31.6% (microscopy). PfHRP-2 showed biomass build-up that climaxed (1813±3410 ng/mL SD) at clinical episodes. CONCLUSION PfHRP-2 ELISA and qPCR may be needed for accurately quantifying the malaria parasite burden. In addition, qPCR improves parasite speciation, whilst PfHRP-2 ELISA is a potential predictor for clinical disease caused by P. falciparum. TRIAL REGISTRATION ClinicalTrials.gov NCT00666380.
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Yuryev A, Kotelnikova E, Daraselia N. Ariadne's ChemEffect and Pathway Studio knowledge base. Expert Opin Drug Discov 2013; 4:1307-18. [PMID: 23480468 DOI: 10.1517/17460440903413488] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
IMPORTANCE OF THE FIELD Drug discovery and development is a very complex and costly process. Understanding the detailed molecular mechanisms of a disease and drug actions can make it more efficient not only for new target discovery but also for lead prioritization, drug repositioning and development of biomarkers for drug efficacy and safety. Access to formalized knowledge about functions of proteins and small molecules is crucial for rationalization of the drug development process, and scientific publications are the main source of this knowledge. Protein knowledge networks capturing protein functions, protein-protein relations and organization of proteins in complex cellular sub-systems are making their way into modern drug discovery. Chemical networks representing multiple aspects of chemical functional information integrated into a protein systems biology network is even more advanced and promising paradigm. AREAS COVERED IN THIS REVIEW This review describes utilization of literature-derived protein and chemical functional knowledge bases in drug development. WHAT THE READER WILL GAIN Readers will gain an understanding of how integrated protein and chemical knowledge networks can be used for understanding and building the models of cellular events, disease mechanisms, and drug actions, finding biomarkers of drug efficacy and safety, as well as interpretation of high-throughput gene expression, proteomic and metabolomic experiments. TAKE HOME MESSAGE Integrated literature-derived protein and chemical knowledge bases can rationalize many aspects of drug development process including drug repositioning and biomarker design.
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Affiliation(s)
- Anton Yuryev
- Ariadne Genomics, Inc. 9430 Key West Ave, Rockville MD, 20850, USA +1 240 453 6296 ; +1 240 453 9026 ;
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Eradication of malaria through genetic engineering: the current situation. ASIAN PAC J TROP MED 2013; 6:85-94. [DOI: 10.1016/s1995-7645(13)60001-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2012] [Revised: 12/15/2012] [Accepted: 01/15/2013] [Indexed: 01/03/2023] Open
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Haanshuus CG, Mohn SC, Mørch K, Langeland N, Blomberg B, Hanevik K. A novel, single-amplification PCR targeting mitochondrial genome highly sensitive and specific in diagnosing malaria among returned travellers in Bergen, Norway. Malar J 2013; 12:26. [PMID: 23336125 PMCID: PMC3556099 DOI: 10.1186/1475-2875-12-26] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2012] [Accepted: 01/17/2013] [Indexed: 11/21/2022] Open
Abstract
Background Nested PCR is a commonly used technique in diagnosis of malaria owing to its high sensitivity and specificity. However, it is time-consuming, open to considerable risk of contamination and has low cost-efficiency. Using amplification targets presented in multiple copies, such as rRNA 18S, or mitochondrial targets with an even higher copy number, might increase sensitivity. Methods The sensitivity and specificity of two newly designed Plasmodium genus-specific single-round amplification PCR programmes, based on previously published primers targeting 18S and mitochondrial genome, were compared with a widely used nested 18S PCR. Analyses of dilution series from Plasmodium falciparum reference material were performed, as well as retrospective analyses of 135 blood samples, evaluated by routine microscopy, from 132 fever patients with potential imported malaria. Sequencing of the 220 bp mitochondrial PCR products was performed. Results At the threshold dilution 0.5 parasites/μl, the sensitivity of the mitochondrial PCR was 97% (29/30 parallels), that of the single-round 18S PCR 93% and the reference nested 18S PCR 87%. All three assays detected as low as 0.05 p/μl, though not consistently. In the patient cohort, malaria was diagnosed in 21% (28/135) samples, defined as positive by at least two methods. Both single-round amplification assays identified all malaria positives diagnosed by nested PCR that had sensitivity of 96% (27/28). The mitochondrial PCR detected one additional sample, also positive by microscopy, and was the only method with 100% sensitivity (28/28). The sensitivity and specificity of the mitochondrial PCR were statistically non-inferior to that of the reference nested PCR. Microscopy missed two infections detected by all PCR assays. Sequencing of the genus-specific mitochondrial PCR products revealed different single nucleotide polymorphisms which allowed species identification of the 28 sequences with following distribution; 20 P. falciparum, six Plasmodium vivax, one Plasmodium ovale and one Plasmodium malariae. Conclusions In this study, design of PCR programmes with suitable parameters and optimization resulted in simpler and faster single-round amplification assays. Both sensitivity and specificity of the novel mitochondrial PCR was 100% and proved non-inferior to that of the reference nested PCR. Sequencing of genus-specific mitochondrial PCR products could be used for species determination.
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Affiliation(s)
- Christel G Haanshuus
- National Centre for Tropical Infectious Diseases, Department of Medicine, Haukeland University Hospital, Bergen, Norway.
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Aneni EC, Hamer DH, Gill CJ. Systematic review of current and emerging strategies for reducing morbidity from malaria in sickle cell disease. Trop Med Int Health 2013; 18:313-27. [PMID: 23320577 DOI: 10.1111/tmi.12056] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Sickle cell disease (SCD) is a chronic debilitating disorder affecting erythrocytes, which is especially prevalent throughout Sub-Saharan Africa and among individuals of African descent. Because malaria is thought to be a significant cause of morbidity and mortality in patients with SCD, malaria chemoprophylaxis is often recommended for these patients. In SCD, malaria chemoprophylaxis reduces malaria parasite count, anaemia and the need for blood transfusion, and improves clinical outcomes. However, the effectiveness of malaria chemoprophylaxis in the setting of SCD is based on a few studies conducted prior to the emergence of widespread antimalarial drug resistance. Consequently, it is uncertain what the optimal strategy for managing patients with SCD in malarious areas should be. Despite the widespread use of hydroxyurea in non-malarious regions, little is known about its effect in malaria-endemic areas or on malaria-related outcomes. On the one hand, hydroxyurea upregulates intercellular cell adhesion molecule 1 (ICAM-1), the cell surface receptor for adhesion of Plasmodium falciparum-infected erythrocytes, and theoretically, it could enhance parasite replication. On the other hand, hydroxyurea increases levels of foetal haemoglobin, which is protective against malaria. We explore what is currently known about the interactions between SCD and malaria and review the published literature on the efficacy of malaria chemoprophylaxis in SCD. We also consider alternative strategies, including hydroxyurea, in the reduction of malaria-associated morbidity and mortality in patients with SCD.
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Affiliation(s)
- Ehimen C Aneni
- Department of International Health, Boston University School of Public Health, Boston, MA 02118, USA.
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Bharate SB, Yadav RR, Khan SI, Tekwani BL, Jacob MR, Khan IA, Vishwakarma RA. Meridianin G and its analogs as antimalarial agents. MEDCHEMCOMM 2013. [DOI: 10.1039/c3md00097d] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Wattal C, Goel N. Infectious disease emergencies in returning travelers: special reference to malaria, dengue fever, and chikungunya. Med Clin North Am 2012; 96:1225-55. [PMID: 23102486 DOI: 10.1016/j.mcna.2012.08.004] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
This review article discusses important infectious illnesses, namely malaria, dengue, and chikungunya, in travelers returning from endemic areas. Malaria and dengue are two of the most common systemic illnesses reported in returning travelers. Because chikungunya is gaining importance, it is also briefly discussed. The clinical significance of these diseases is mainly due to the possibility of sudden deterioration with high mortality in clinically healthy looking patients. The key clinical features, their diagnosis, and treatment algorithms are discussed in detail to help in early diagnosis and appropriate clinical management of such travelers presenting in emergency departments.
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Affiliation(s)
- Chand Wattal
- Department of Clinical Microbiology and Immunology, Sir Ganga Ram Hospital, Rajinder Nagar, New Delhi, India.
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In Vitro Chloroquine Resistance in Plasmodium falciparum Isolates from Tertiary Care Hospital. Malar Res Treat 2012; 2012:538481. [PMID: 23050196 PMCID: PMC3462382 DOI: 10.1155/2012/538481] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2012] [Revised: 08/03/2012] [Accepted: 08/29/2012] [Indexed: 12/03/2022] Open
Abstract
Chloroquine (CQ) has been the mainstay of treatment of malaria for decades. This cost-effective and safe drug has become ineffective for treatment
of falciparum malaria in many parts of the world due to development of resistance by the parasite. In addition CQ is not gametocytocidal for P. falciparum and thus cannot block transmission. The extent of problem of chloroquine resistance in
P. falciparum is increasing every year. The study was done in period of 2 years. A total of 5653 specimens were examined for malarial infection by employing different diagnostic modalities. Four hundred and thirty-five were found to be positive for P. falciparum by using different diagnostic techniques. All positive specimens were cultured on RPMI 1640 medium; only 108 were found to be culture positive. Sensitivity of isolates to chloroquine was done using Mark III WHO sensitivity plates.
The prevalence of malaria infection was found 9.54% in 2010. There were schizont formation at 8 pmol/liter or more of chloroquine concentration in 26 isolates. The emergence of chloroquine (CQ) resistance pattern
in Aligarh isolates increases. Antimalarial agents should be used with caution; monotherapies should be avoided.
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De Donno A, Grassi T, Idolo A, Guido M, Papadia P, Caccioppola A, Villanova L, Merendino A, Bagordo F, Fanizzi FP. First-time comparison of the in vitro antimalarial activity of Artemisia annua herbal tea and artemisinin. Trans R Soc Trop Med Hyg 2012; 106:696-700. [PMID: 22986092 DOI: 10.1016/j.trstmh.2012.07.008] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2011] [Revised: 07/16/2012] [Accepted: 07/16/2012] [Indexed: 01/27/2023] Open
Abstract
Artemisia annua tea has been proven to be a very effective treatment for malaria in various clinical trials, but to date its efficacy has not been investigated in vitro. A study was therefore performed to evaluate the effects of A. annua tea on Plasmodium falciparum cultures in vitro. The concentration of artemisinin in the herbal tea preparation was also determined. The herbal tea extract was tested against chloroquine (CQ)-sensitive D10 and CQ-resistant W2 strains of P. falciparum using the parasite lactate dehydrogenase assay. Quantification of artemisinin in the extract of leaves of A. annua was performed using proton nuclear magnetic resonance ((1)H-NMR). Results of the in vitro tests were consistent with the clinical efficacy of A. annua tea [50% inhibitory concentration (IC(50)) for strain D10=1.11±0.21 μg/ml; IC(50) for strain W2=0.88±0.35 μg/ml]. The concentration of artemisinin in A. annua tea (0.18±0.02% of dry weight) was far too low to be responsible for the antimalarial activity. The artemisinin present in the tea is probably co-solubilised with other ingredients, some of which also have antimalarial activity and act synergistically with it. These compounds also merit further research to determine whether their presence hinders the development of parasite resistance compared with pure artemisinin.
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Affiliation(s)
- Antonella De Donno
- Laboratory of Hygiene, Department of Biological and Environmental Science and Technology (DiSTeBA), University of Salento, Via Prov. le Lecce-Monteroni, 73100 Lecce, Italy.
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84
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Takashima Y, Mizohata E, Krungkrai SR, Fukunishi Y, Kinoshita T, Sakata T, Matsumura H, Krungkrai J, Horii T, Inoue T. The in silico screening and X-ray structure analysis of the inhibitor complex of Plasmodium falciparum orotidine 5'-monophosphate decarboxylase. J Biochem 2012; 152:133-8. [PMID: 22740703 DOI: 10.1093/jb/mvs070] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Orotidine 5'-monophosphate decarboxylase from Plasmodium falciparum (PfOMPDC) catalyses the final step in the de novo synthesis of uridine 5'-monophosphate (UMP) from orotidine 5'-monophosphate (OMP). A defective PfOMPDC enzyme is lethal to the parasite. Novel in silico screening methods were performed to select 14 inhibitors against PfOMPDC, with a high hit rate of 9%. X-ray structure analysis of PfOMPDC in complex with one of the inhibitors, 4-(2-hydroxy-4-methoxyphenyl)-4-oxobutanoic acid, was carried out to at 2.1 Å resolution. The crystal structure revealed that the inhibitor molecule occupied a part of the active site that overlaps with the phosphate-binding region in the OMP- or UMP-bound complexes. Space occupied by the pyrimidine and ribose rings of OMP or UMP was not occupied by this inhibitor. The carboxyl group of the inhibitor caused a dramatic movement of the L1 and L2 loops that play a role in the recognition of the substrate and product molecules. Combining part of the inhibitor molecule with moieties of the pyrimidine and ribose rings of OMP and UMP represents a suitable avenue for further development of anti-malarial drugs.
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Affiliation(s)
- Yasuhide Takashima
- Department of Applied Chemistry, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
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85
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M EE, Ezeiruaku FC, Ukaji DC. Experiential relationship between malaria parasite density and some haematological parameters in malaria infected male subjects in Port Harcourt, Nigeria. Glob J Health Sci 2012; 4:139-48. [PMID: 22980350 PMCID: PMC4776939 DOI: 10.5539/gjhs.v4n4p139] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2012] [Accepted: 06/15/2012] [Indexed: 11/12/2022] Open
Abstract
This study examined the experiential relationship between the parasite density and haematological parameters in male patients with Plasmodium falciparum infection in Port Harcourt, Nigeria reporting to malaria clinics. A total of one hundred and thirty-six (136) male patients were recruited. QBC haematological analysis, QBC malaria parasite specie identification and quantification and thin blood film for differential leucocytes count was used. The mean values of the haematological parameters in each quartile of parasite densities were determined using Microsoft Excel statistical package. Regression analysis was employed to model the experiential relationship between parasite density and haematological parameters. All regression relationships were tested and the relationship with the highest coefficient of determination (R2) was accepted as the valid relationship. The relationships tested included linear, polynomial, exponential, logarithmic and power relationships. The X- axis of the regression graphs stand for the parasite density while Y-axis stands for the respective haematological parameters Neutrophil count had a negative exponential relationship with the parasite density and is related to the parasite density by a polynomial equation model: ynm = -7E-07x2 - 0.0003x + 56.685. The coefficient of determination (R2) was 0.6140. This means that the rate of change of the parasitemia will depend on the initial value of the neutrophil. As the neutrophil increases, the parasitemia will tend to decrease in a double, triple and quadruple manner. The relationship between lymphocyte count, monocyte count and eosinophil count and parasite density was logarithmic and expressed by the following linear equation models: ylm = -2.371ln(x) + 37.296, ymm = 0.6965ln(x) + 5.7692 and yem = 0.9334ln(x) + 4.1718 in the same order. Their respective high coefficients of determination (R2) were 0.8027, 0.8867 and 0.9553. This logarithmic relationship means that each doubling of monocyte count and eosinophil count will cause the same amount of increase in parasitemia whereas each doubling of lymphocyte count will cause the same amount of decrease in parasitemia. The best fitting regression model for total white cell count (WBC), haemoglobin concentration, packed cell volume (PCV)(haematocrit) and mean cell haemoglobin concentration (MCHC) and parasite density was a linear model and expressed by the following linear equation models: yWBCm = 1.2314x + 8533.8, yHbm = -0.0014x + 13.004, yPCVm = -0.0046x + 41.443 and yMCHCm = -0.0008x + 32.336. Their respective coefficients of determination are 0.7397, 0.6248, 0.9758 and 0.8584. This linear relationship means that as the parasite density is increasing that there is a corresponding decrease in haemoglobin concentration, PCV and MCHC and a corresponding increase in total white cell count. The best fitting regression model between platelet count and parasite density is a power model with a very high coefficient of determination (R2=0.9938) and expressed by: yPltm = 278047x-0.122. These equation models could be very useful in areas where there may not be functional microscopes or competent microscopists and in medical emergencies.
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Affiliation(s)
- Eze Evelyn M
- Department of Haematology and Transfusion Science, Madonna University, Elele, Nigeria.
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86
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Summers RL, Nash MN, Martin RE. Know your enemy: understanding the role of PfCRT in drug resistance could lead to new antimalarial tactics. Cell Mol Life Sci 2012; 69:1967-95. [PMID: 22286067 PMCID: PMC11115045 DOI: 10.1007/s00018-011-0906-0] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2011] [Revised: 11/22/2011] [Accepted: 12/06/2011] [Indexed: 10/14/2022]
Abstract
The prevention and treatment of malaria is heavily dependent on antimalarial drugs. However, beginning with the emergence of chloroquine (CQ)-resistant Plasmodium falciparum parasites 50 years ago, efforts to control the disease have been thwarted by failed or failing drugs. Mutations in the parasite's 'chloroquine resistance transporter' (PfCRT) are the primary cause of CQ resistance. Furthermore, changes in PfCRT (and in several other transport proteins) are associated with decreases or increases in the parasite's susceptibility to a number of other antimalarial drugs. Here, we review recent advances in our understanding of CQ resistance and discuss these in the broader context of the parasite's susceptibilities to other quinolines and related drugs. We suggest that PfCRT can be viewed both as a 'multidrug-resistance carrier' and as a drug target, and that the quinoline-resistance mechanism is a potential 'Achilles' heel' of the parasite. We examine a number of the antimalarial strategies currently undergoing development that are designed to exploit the resistance mechanism, including relatively simple measures, such as alternative CQ dosages, as well as new drugs that either circumvent the resistance mechanism or target it directly.
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Affiliation(s)
- Robert L. Summers
- Research School of Biology, The Australian National University, Canberra, ACT 0200 Australia
| | - Megan N. Nash
- Research School of Biology, The Australian National University, Canberra, ACT 0200 Australia
| | - Rowena E. Martin
- Research School of Biology, The Australian National University, Canberra, ACT 0200 Australia
- School of Botany, University of Melbourne, Parkville, VIC 3010 Australia
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87
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Martins JS, Zwi AB, Hobday K, Bonaparte F, Kelly PM. The implementation of a new Malaria Treatment Protocol in Timor-Leste: challenges and constraints. Health Policy Plan 2012; 27:677-86. [PMID: 22460007 PMCID: PMC3513764 DOI: 10.1093/heapol/czs019] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Background Timor-Leste changed its malaria treatment protocol in 2007, replacing the first-line for falciparum malaria from sulphadoxine-pyrimethamine to artemether-lumefantrine. This study explored the factors affecting the implementation of the revised treatment protocol, with an emphasis on identifying key constraints. Methods A mixed method approach drew on both qualitative and quantitative data. The study included data from District Health Services in seven districts, community health centres in 14 sub-districts, four hospitals, five private clinics, one private pharmacy and the country's autonomous medical store. In-depth interviews with 36 key informants, five group interviews and 15 focus group discussions were conducted. A survey was also undertaken at community health centres and hospitals to assess the availability of a physical copy of the Malaria Treatment Protocol, as well as the availability and utilization of artemether-lumefantrine and sulphadoxine-pyrimethamine. Results Many factors impeded the implementation of the new malaria protocol. These included: inadequate introduction and training around the revised treatment protocol; unclear phasing out of sulphadoxine-pyrimethamine and phasing in of the revised treatment, artemether-lumefantrine, and the rapid diagnostic test (RDT); lack of supervision; lack of adherence to the revised guidelines by foreign health workers; lack of access to the new drug by the private sector; obstacles in the procurement process; and the use of trade names rather than generic drug description. Insufficient understanding of the rapid diagnostic test and the untimely supply of drugs further hampered implementation. Conclusion To effectively implement a revised malaria treatment protocol, barriers should be identified during the policy formulation process and those emerging during implementation should be recognized promptly and addressed.
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Affiliation(s)
- João Soares Martins
- School of Public Health and Community Medicine, The University of New South Wales, Sydney, NSW 2052, Australia.
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88
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Erdelyan CNG, Mahood TH, Bader TSY, Whyard S. Functional validation of the carbon dioxide receptor genes in Aedes aegypti mosquitoes using RNA interference. INSECT MOLECULAR BIOLOGY 2012; 21:119-127. [PMID: 22122783 DOI: 10.1111/j.1365-2583.2011.01120.x] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Carbon dioxide (CO(2)) is an important long-range chemosensory cue used by blood-feeding female mosquitoes to find their hosts. The CO(2) receptor in Drosophila melanogaster was previously determined to be a heterodimer comprised of two gustatory receptor (Gr) proteins, DmGr21a and DmGr63a. In the mosquito Aedes aegypti, two putative orthologous genes, AaGr1 and AaGr3, were identified in the genome database, along with an apparent paralogue of AaGr1, AaGr2. In this study, RNA interference (RNAi)-mediated gene knockdown of either AaGr1 or AaGr3 resulted in a loss of CO(2) sensitivity in both male and female mosquitoes, suggesting that these two proteins, like the Drosophila orthologues, function as a heterodimer. RNAi-mediated knockdown of AaGr2 expression had no impact on CO(2) reception. All three Gr genes were expressed in the maxillary palps of both Ae. aegypti and the West Nile virus vector mosquito, Culex pipiens quinquefasciatus. Interestingly, expression of the two CO(2) receptor genes was not equivalent in the two sexes and the implications of differential sex expression of the CO(2) receptor in different species are discussed. The functional identification of the CO(2) receptor in a mosquito could prove invaluable in the strategic design of compounds that disrupt the mosquito's ability to find hosts.
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Affiliation(s)
- C N G Erdelyan
- Department of Biological Sciences, University of Manitoba, Winnipeg, MB, Canada
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89
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Takashima Y, Mizohata E, Tokuoka K, Krungkrai SR, Kusakari Y, Konishi S, Satoh A, Matsumura H, Krungkrai J, Horii T, Inoue T. Crystallization and preliminary X-ray diffraction analysis of orotate phosphoribosyltransferase from the human malaria parasite Plasmodium falciparum. Acta Crystallogr Sect F Struct Biol Cryst Commun 2012; 68:244-6. [PMID: 22298010 PMCID: PMC3274414 DOI: 10.1107/s1744309111043247] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2011] [Accepted: 10/19/2011] [Indexed: 11/10/2022]
Abstract
Orotate phosphoribosyltransferase (OPRT) catalyzes the Mg(2+)-dependent condensation of orotic acid (OA) with 5-α-D-phosphorylribose 1-diphosphate (PRPP) to yield diphosphate (PP(i)) and the nucleotide orotidine 5'-monophosphate. OPRT from Plasmodium falciparum produced in Escherichia coli was crystallized by the sitting-drop vapour-diffusion method in complex with OA and PRPP in the presence of Mg(2+). The crystal exhibited tetragonal symmetry, belonging to space group P4(1) or P4(3), with unit-cell parameters a = b = 49.15, c = 226.94 Å. X-ray diffraction data were collected to 2.5 Å resolution at 100 K using a synchrotron-radiation source.
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Affiliation(s)
- Yasuhide Takashima
- Division of Applied Chemistry, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Eiichi Mizohata
- Division of Applied Chemistry, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Keiji Tokuoka
- Division of Applied Chemistry, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Sudaratana R. Krungkrai
- Unit of Biochemistry, Department of Medical Science, Faculty of Science, Rangsit University, Patumthani 12000, Thailand
| | - Yukiko Kusakari
- Division of Applied Chemistry, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Saki Konishi
- Division of Applied Chemistry, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Atsuko Satoh
- Division of Applied Chemistry, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Hiroyoshi Matsumura
- Division of Applied Chemistry, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Jerapan Krungkrai
- Department of Biochemistry, Faculty of Medicine, Chulalongkorn University, Rama IV Road, Bangkok 10330, Thailand
| | - Toshihiro Horii
- Department of Molecular Protozoology, Research Institute for Microbial Diseases, Osaka University, 3-1 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Tsuyoshi Inoue
- Division of Applied Chemistry, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
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90
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Kritsiriwuthinan K, Ngrenngarmlert W. Asymptomatic malaria infections among foreign migrant workers in Thailand. ASIAN PAC J TROP MED 2012; 4:560-3. [PMID: 21803309 DOI: 10.1016/s1995-7645(11)60146-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2011] [Revised: 06/11/2011] [Accepted: 06/15/2011] [Indexed: 10/17/2022] Open
Abstract
OBJECTIVE To determine the prevalence of malaria infections among foreign migrant workers in Thailand. METHODS Giemsa-stained thin and thick blood films were prepared from blood samples of 294 foreign migrant workers recruited in the study. Microscopic examination of these blood films was performed for malaria detection. RESULTS Blood film examination revealed 1.36% malaria infections in these 294 subjects. All positive cases were male Myanmar workers in which their blood films only ring stage of Plasmodium spp. was found at low parasite density (mean= 144 parasites/μ L of blood). The prevalence of malaria infections was not significantly different among foreign migrant workers classified by age, gender, and resident province (P>0.05). Thin blood films of these workers also showed 78.91% hypochromic erythrocytes and 61.9% relative Eosinophilia. CONCLUSIONS These findings indicate a high risk of malaria transmission. Therefore active malaria surveillance by using molecular methods with more sensitive and specific than microscopy should be considered for malaria control in foreign migrant workers.
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91
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Kamau E, Alemayehu S, Feghali KC, Tolbert LS, Ogutu B, Ockenhouse CF. Development of a TaqMan Allelic Discrimination assay for detection of single nucleotides polymorphisms associated with anti-malarial drug resistance. Malar J 2012; 11:23. [PMID: 22264294 PMCID: PMC3273427 DOI: 10.1186/1475-2875-11-23] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2011] [Accepted: 01/20/2012] [Indexed: 12/04/2022] Open
Abstract
Background Anti-malarial drug resistance poses a threat to current global efforts towards control and elimination of malaria. Several methods are used in monitoring anti-malarial drug resistance. Molecular markers such as single nucleotide polymorphism (SNP) for example are increasingly being used to identify genetic mutations related to anti-malarial drug resistance. Several methods are currently being used in analysis of SNP associated with anti-malarial drug resistance and although each one of these methods has unique strengths and shortcoming, there is still need to improve and/or develop new methods that will close the gap found in the current methods. Methods TaqMan Allelic Discrimination assays for detection of SNPs associated with anti-malarial drug resistance were designed for analysis on Applied Biosystems PCR platform. These assays were designed by submitting SNP sequences associated with anti-malarial drug resistance to Applied Biosystems website. Eleven SNPs associated with resistance to anti-malarial drugs were selected and tested. The performance of each SNP assay was tested by creating plasmid DNAs carrying codons of interests and analysing them for analysis. To test the sensitivity and specificity of each SNP assay, 12 clinical samples were sequenced at codons of interest and used in the analysis. Plasmid DNAs were used to establish the Limit of Detection (LoD) for each assay. Results Data from genetic profiles of the Plasmodium falciparum laboratory strains and sequence data from 12 clinical samples was used as the reference method with which the performance of the SNP assays were compared to. The sensitivity and specificity of each SNP assay was establish at 100%. LoD for each assay was established at 2 GE, equivalent to less than 1 parasite/μL. SNP assays performed well in detecting mixed infection and analysis of clinical samples. Conclusion TaqMan Allelic Discrimination assay provides a good alternative tool in detection of SNPs associated with anti-malarial drug.
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Affiliation(s)
- Edwin Kamau
- Military Malaria Research Program, Malaria Vaccine Branch, Department of Molecular Diagnostics and Genomic Studies, Walter Reed Army Institute of Research, 503 Robert Grant Ave, Silver Spring, 20 Maryland, USA.
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92
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Changes in malaria morbidity and mortality in Mpumalanga Province, South Africa (2001-2009): a retrospective study. Malar J 2012; 11:19. [PMID: 22239855 PMCID: PMC3292497 DOI: 10.1186/1475-2875-11-19] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2011] [Revised: 11/01/2011] [Accepted: 01/13/2012] [Indexed: 11/16/2022] Open
Abstract
Background Malaria remains a serious epidemic threat in Mpumalanga Province. In order to appropriately target interventions to achieve substantial reduction in the burden of malaria and ultimately eliminate the disease, there is a need to track progress of malaria control efforts by assessing the time trends and evaluating the impact of current control interventions. This study aimed to assess the changes in the burden of malaria in Mpumalanga Province during the past eight malaria seasons (2001/02 to 2008/09) and whether indoor residual spraying (IRS) and climate variability had an effect on these changes. Methods This is a descriptive retrospective study based on the analysis of secondary malaria surveillance data (cases and deaths) in Mpumalanga Province. Data were extracted from the Integrated Malaria Information System. Time series model (Autoregressive Integrated Moving Average) was used to assess the association between climate and malaria. Results Within the study period, a total of 35,191 cases and 164 deaths due to malaria were notified in Mpumalanga Province. There was a significant decrease in the incidence of malaria from 385 in 2001/02 to 50 cases per 100,000 population in 2008/09 (P < 0.005). The incidence and case fatality (CFR) rates for the study period were 134 cases per 100,000 and 0.54%, respectively. Mortality due to malaria was lower in infants and children (CFR < 0.5%) and higher in those >65 years, with the mean CFR of 2.1% as compared to the national target of 0.5%. A distinct seasonal transmission pattern was found to be significantly related to changes in rainfall patterns (P = 0.007). A notable decline in malaria case notification was observed following apparent scale-up of IRS coverage from 2006/07 to 2008/09 malaria seasons. Conclusions Mpumalanga Province has achieved the goal of reducing malaria morbidity and mortality by over 70%, partly as a result of scale-up of IRS intervention in combination with other control strategies. These results highlight the need to continue with IRS together with other control strategies until interruption in local malaria transmission is completely achieved. However, the goal to eliminate malaria as a public health problem requires efforts to be directed towards the control of imported malaria cases; development of strategies to interrupt local transmission; and maintaining high quality surveillance and reporting system.
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93
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Clark RL. Effects of artemisinins on reticulocyte count and relationship to possible embryotoxicity in confirmed and unconfirmed malarial patients. ACTA ACUST UNITED AC 2011; 94:61-75. [PMID: 22125126 DOI: 10.1002/bdra.22868] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2011] [Revised: 09/01/2011] [Accepted: 09/07/2011] [Indexed: 01/28/2023]
Abstract
Rat studies suggest that artemisinin-induced decreases in reticulocyte count are a marker for embryotoxicity (in one study, r = 0.82; p < 0.05). In clinical studies, therapeutic doses of artemisinins induced decreases in reticulocyte count that were larger in five of six groups of healthy volunteers (mean decreases of 47-75%) than in 12 groups of patients with malaria (mean decreases of 0-34% and incidences of low reticulocyte count of 0.6-18%). Malaria causes hypoferremia and drug concentrates in infected red cells so, among the explanations for the lesser decreases in patients, is that malaria protects against artemisinin-induced decreases in reticulocyte count by reducing the target tissue levels of active drug and/or ferrous iron which activates the drug to toxic free radicals. The disease could also protect against embryotoxicity in which case pregnant women without malaria would be at greater risk of artemisinin-induced embryotoxicity. Malaria protection against artesunate toxicity has been observed in rats. No artemisinin-induced embryotoxicity has been identified in limited numbers of women with confirmed malaria in the first trimester. However, in large parts of tropical Africa, malaria treatment is based on fever rather than confirmation of parasitemia and many pregnant women without malaria are exposed to antimalarials. No clinical studies have been conducted on uninfected women for whom pregnancy was identified and then an artemisinin was administered subsequently. Testing in rats and/or humans is needed to determine if malaria protects against reticulocytopenia and embryotoxicity and whether the parasite is a more or less sensitive target than the embryo and reticulocyte.
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Affiliation(s)
- Robert L Clark
- Artemis Pharmaceutical Research, 1758 Allentown Road, Lansdale, Pennsylvania, USA.
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94
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Flegg JA, Guerin PJ, White NJ, Stepniewska K. Standardizing the measurement of parasite clearance in falciparum malaria: the parasite clearance estimator. Malar J 2011; 10:339. [PMID: 22074219 PMCID: PMC3305913 DOI: 10.1186/1475-2875-10-339] [Citation(s) in RCA: 212] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2011] [Accepted: 11/10/2011] [Indexed: 11/10/2022] Open
Abstract
Background A significant reduction in parasite clearance rates following artesunate treatment of falciparum malaria, and increased failure rates following artemisinin combination treatments (ACT), signaled emergent artemisinin resistance in Western Cambodia. Accurate measurement of parasite clearance is therefore essential to assess the spread of artemisinin resistance in Plasmodium falciparum. The slope of the log-parasitaemia versus time relationship is considered to be the most robust measure of anti-malarial effect. However, an initial lag phase of numerical instability often precedes a steady exponential decline in the parasite count after the start of anti-malarial treatment. This lag complicates the clearance estimation, introduces observer subjectivity, and may influence the accuracy and consistency of reported results. Methods To address this problem, a new approach to modelling clearance of malaria parasites from parasitaemia-time profiles has been explored and validated. The methodology detects when a lag phase is present, selects the most appropriate model (linear, quadratic or cubic) to fit log-transformed parasite data, and calculates estimates of parasite clearance adjusted for this lag phase. Departing from previous approaches, parasite counts below the level of detection are accounted for and not excluded from the calculation. Results Data from large clinical studies with frequent parasite counts were examined. The effect of a lag phase on parasite clearance rate estimates is discussed, using individual patient data examples. As part of the World Wide Antimalarial Resistance Network's (WWARN) efforts to make innovative approaches available to the malaria community, an automated informatics tool: the parasite clearance estimator has been developed. Conclusions The parasite clearance estimator provides a consistent, reliable and accurate method to estimate the lag phase and malaria parasite clearance rate. It could be used to detect early signs of emerging resistance to artemisinin derivatives and other compounds which affect ring-stage clearance.
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Affiliation(s)
- Jennifer A Flegg
- WorldWide Anti-malarial Resistance Network (WWARN) and Centre for Tropical Medicine, Nuffield Department of Clinical Medicine, University of Oxford, Churchill Hospital, Old Road, Oxford, OX3 7LJ, UK
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95
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Helichrysum gymnocephalum essential oil: chemical composition and cytotoxic, antimalarial and antioxidant activities, attribution of the activity origin by correlations. Molecules 2011; 16:8273-91. [PMID: 21959299 PMCID: PMC6264711 DOI: 10.3390/molecules16108273] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2011] [Revised: 09/23/2011] [Accepted: 09/23/2011] [Indexed: 11/16/2022] Open
Abstract
Helichrysum gymnocephalum essential oil (EO) was prepared by hydrodistillation of its leaves and characterized by GC-MS and quantified by GC-FID. Twenty three compounds were identified. 1,8-Cineole (47.4%), bicyclosesquiphellandrene (5.6%), γ-curcumene (5.6%), α-amorphene (5.1%) and bicyclogermacrene (5%) were the main components. Our results confirmed the important chemical variability of H. gymnocephalum. The essential oil was tested in vitro for cytotoxic (on human breast cancer cells MCF-7), antimalarial (Plasmodium falciparum: FcB1-Columbia strain, chloroquine-resistant) and antioxidant (ABTS and DPPH assays) activities. H. gymnocephalum EO was found to be active against MCF-7 cells, with an IC(50) of 16 ± 2 mg/L. The essential oil was active against P. falciparum (IC(50) = 25 ± 1 mg/L). However, the essential oil exhibited a poor antioxidant activity in the DPPH (IC(50) value > 1,000 mg/L) and ABTS (IC(50) value = 1,487.67 ± 47.70 mg/L) assays. We have reviewed the existing results on the anticancer activity of essential oils on MCF-7 cell line and on their antiplasmodial activity against the P. falciparum. The aim was to establish correlations between the identified compounds and their biological activities (antiplasmodial and anticancer). β-Selinene (R² = 0.76), α-terpinolene (R² = 0.88) and aromadendrene (R² = 0.90) presented a higher relationship with the anti-cancer activity. However, only calamenene (R² = 0.70) showed a significant correlation for the antiplasmodial activity.
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Devakaram R, Black DS, Andrews KT, Fisher GM, Davis RA, Kumar N. Synthesis and antimalarial evaluation of novel benzopyrano[4,3-b]benzopyran derivatives. Bioorg Med Chem 2011; 19:5199-206. [DOI: 10.1016/j.bmc.2011.07.009] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2011] [Revised: 06/30/2011] [Accepted: 07/06/2011] [Indexed: 10/18/2022]
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Clark RL, Brannen KC, Sanders JE, Hoberman AM. Artesunate and artelinic acid: association of embryotoxicity, reticulocytopenia, and delayed stimulation of hematopoiesis in pregnant rats. ACTA ACUST UNITED AC 2011; 92:52-68. [PMID: 21312322 DOI: 10.1002/bdrb.20282] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The artemisinin antimalarials cause embryo death and malformations in animals by killing embryonic erythroblasts. Groups of pregnant rats (N = 4) were administered 35 and 48 µmol/kg artesunate and 17.2, 28.7, 48, 96, and 191 µmol/kg artelinic acid as a single oral dose on gestational day (GD) 12. Litters were examined on GD21. The ED(50) for embryo death with artelinic acid (23.4 µmol/kg) was just slightly lower than that for decreased reticulocyte count at 24 hr postdose (33.5 µmol/kg) and both had similarly steep dose responses (maximal effects of total litter loss and ∼60% decreases in reticulocyte count at 48 µmol/kg). Results with artesunate were similar. The correlation coefficient between embryo death and decreased reticulocyte count was 0.82 (p<0.01). The close relationship between embryotoxicity and reticulocytopenia is suggestive of a common mechanism-artemisinin-induced mitochondrial damage leading to cell death. At 9 days postdose, treatment with artesunate and artelinic acid also caused increases in counts of reticulocytes, lymphocytes, basophils, and monocytes (up to 3.7 ×, 1.7 ×, 4.7 ×, and 1.7 × control, respectively). This stimulation of hematopoiesis may have been mediated by the direct oxidative conversion of artesunate or artelinic acid to the artemisininyl hydroperoxide within the bone marrow cells or by an indirect increase in reactive oxygen species. The high correlation between embryotoxicity and reticulocytopenia further supports the assertion that therapeutic dosage regimens of artemisinins that cause decreases in reticulocyte count in pregnant women during the putative critical period (approximately postconception wk 3 to 9) are at risk of also causing adverse effects on the embryo.
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Affiliation(s)
- Robert L Clark
- Artemis Pharmaceutical Research, Lansdale, PA 19446, USA.
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Agrawal VK. Plasmodium falciparum Containment Strategy. Med J Armed Forces India 2011; 64:57-60. [PMID: 27408082 DOI: 10.1016/s0377-1237(08)80150-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2005] [Accepted: 11/28/2005] [Indexed: 11/24/2022] Open
Abstract
World Health Organization (WHO) estimates 1.7-2.5 million deaths and 300-500 million cases of malaria each year globally. As an initiative WHO has announced Roll Back Malaria (RBM) programme aimed at 50% reduction in deaths due to malaria by 2010. The RBM strategy recommends combination approach with prevention, care, creating sustainable demand for insecticide treated nets (ITNs) and efficacious antimalarials in order to achieve sustainable malaria control. Malaria control in India has travelled a long way from National Malaria Control Programme launched in 1953 to National Vector Borne Diseases Control Programme in 2003. In India, the malaria eradication concept was based on indoor residual spraying to interrupt transmission and mop up cases by vigilance. This programme was successful in reducing the malaria cases from 75 million in 1953 to 2 million but subsequently resulted in vector and parasite resistance as well as increase in P falciparum from 30-48%. In view of rapidly growing resistance of Plasmodium falciparum to conventional monotherapies and its spread in newer areas, the programme was modified with inclusion of RBM interventions and revision of treatment guidelines for malaria. Early case detection and prompt treatment, selective vector control, promotion of personal protective measures including ITNs and information, education, communication to achieve wider community participation will be the key interventions in the revised programme.
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Affiliation(s)
- V K Agrawal
- Reader, Department of Community Medicine, Armed Forces Medical College, Pune-411040
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Design, synthesis and biological evaluation of some novel 3-cinnamoyl-4-hydroxy-2H-chromen-2-ones as antimalarial agents. Med Chem Res 2011. [DOI: 10.1007/s00044-011-9694-1] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Chanda P, Hamainza B, Moonga HB, Chalwe V, Banda P, Pagnoni F. Relative costs and effectiveness of treating uncomplicated malaria in two rural districts in Zambia: implications for nationwide scale-up of home-based management. Malar J 2011; 10:159. [PMID: 21651828 PMCID: PMC3121654 DOI: 10.1186/1475-2875-10-159] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2011] [Accepted: 06/09/2011] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Malaria case management is one of the key strategies to control malaria. Various studies have demonstrated the feasibility of home management of malaria (HMM). However, data on the costs and effectiveness of artemisinin-based combination therapy (ACT) and rapid diagnostic tests via HMM is limited. METHOD Cost-effectiveness of home management versus health facility-based management of uncomplicated malaria in two rural districts in Zambia was analysed from a providers' perspective. The sample included 16 community health workers (CHWs) and 15 health facilities. The outcome measure was the cost per case appropriately diagnosed and treated. Costs of scaling-up HMM nationwide were estimated based on the CHW utilisation rates observed in the study. RESULTS HMM was more cost effective than facility-based management of uncomplicated malaria. The cost per case correctly diagnosed and treated was USD 4.22 for HMM and USD 6.12 for facility level. Utilization and adherence to diagnostic and treatment guidelines was higher in HMM than at a health facility. CONCLUSION HMM using ACT and RDTs was more efficient at appropriately diagnosing and treating malaria than the health facility level. Scaling up this intervention requires significant investments.
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Affiliation(s)
- Pascalina Chanda
- Department of Public Health and Research, Ministry of Health Headquarters, Lusaka, Zambia.
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