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Query: UMLS:C0024530 (malaria)
 44,886 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In Brazil, no study has been done concerning the detection of malaria parasites by polymerase chain reaction (PCR) related to the diagnosis of Plasmodium falciparum malaria. In the present report we describe a highly sensitive methodology for malaria diagnosis using a nested PCR method based on amplification of the p126 P. falciparum gene detected by simple ethidium bromide staining. The P. falciparum Palo Alto strain (culture samples) was serially diluted in blood from an uninfected donor to a final level of parasitemia corresponding to 10(-8)% and was processed for PCR amplification. In each of these dilutions a parasitological examination was performed to compare the sensitivity with that of PCR amplification. Blood samples (field samples) were obtained from 51 malarious patients with positive thick blood smears (TBS) who were living in endemic regions of the Brazilian Amazon. They corresponded to 42 P. falciparum and 9 P. vivax cases, with parasitemia levels ranging from only 16 to 20,200 parasites/microliter for P. falciparum disease and from 114 to 11,000 parasites/microliter for P. vivax malaria. We demonstrate that the use of nested PCR allows the detection of 0.005 parasites/microliter without the use of radioactive material. The use of a 1-ml sample volume and the organic DNA extraction method should be suitable in blood banks and for the evaluation of patients during and after drug treatment.
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PMID:Malaria diagnosis: standardization of a polymerase chain reaction for the detection of Plasmodium falciparum parasites in individuals with low-grade parasitemia. 887 68

Species-specific differences in the nucleotide sequences of the 2nd internal transcribed spacer (ITS2) of nuclear ribosomal DNA (rDNA) were used to develop a diagnostic assay based on the polymerase chain reaction (PCR) that can distinguish 4 of the 5 cryptic sibling species in the common malaria mosquito, Anopheles quadrimaculatus Say, complex. The assay requires only a small amount of tissue from an individual mosquito and a mixture of 5 PCR primers. The plus strand universal primer is derived from a sequence in the 5.8S coding region that is identical in all members of the complex. The 4 minus strand primers were selected from species-unique sequences within the ITS2 region. PCR amplification produces a different sized fragment for each of the 4 species which can be visualized readily under ultraviolet light after electrophoresis through an ethidium bromide-containing agarose gel. The assay has been developed and tested only with An. quadrimaculatus complex specimens from Florida populations.
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PMID:Polymerase chain reaction species diagnostic assay for Anopheles quadrimaculatus cryptic species (Diptera: Culicidae) based on ribosomal DNA ITS2 sequences. 890 13

This article describes some negative effects from modernization and urban growth in South America, including disease, pesticides, occupational hazards, poor environmental controls of water and garbage, sanitation, and environmental degradation. South America is following the global trend toward urbanization and the problems that accompany it. Agricultural expansion led to an expanded market for pesticides that includes the deadly DDT, paraquat, and heptachlor. Brazil and Colombia are the largest consumers. Latin American officials justify use of DDT, which is banned in the US and many European countries, as an effective means of combating mosquitos that carry malaria. Exposure occurs during harvesting, transporting, forestry, livestock farming, and vector control activities. Methyl bromide, which is used post-harvest and as a soil fumigant, is dangerous enough to be banned in the US in 2001, and in developing countries in 2002. Exposure to toxic chemicals can severely inhibit enzyme action that is necessary for neurological functioning. A hot climate, which prevents protective clothing, lack of education on proper application, and absence of water to wash exposed skin, make pesticide protection very difficult. Over 40 million agricultural workers are at risk of pesticide poisoning. Habitat destruction has contributed to increased mosquito infestations. Children in the workplace are at even greater risk of noise pollution and chemical poisoning. South America pollutes almost 11 times more fresh water per capita than Europe. About 70% of domestic garbage is collected, and about 30% is disposed of correctly. Only 10% of urban wastewater is treated before discharge into waterways. The loss of coastal wetlands reduces the ability of waterways to filter and absorb nutrients. Environmental health problems suggest an interlinkage between environmental sustainability, human health, and economic growth.
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PMID:Growing pains in South America. 934 93

A non-radioactive method for in situ hybridisation of Restriction Fragment Length Polymorphic (RFLP) markers to the polytene chromosome of Anopheles gambiae, the important malaria vector, which yielded good readable quality of chromosomal bands is reported. The methodology adopted was a Biotin-Streptavidin-Alkaline Phosphatase system which yielded fluorescent signals when stained with dyes such as Nitro Blue Tetrazolium and Bromo Chloro Indolyl Phosphate.
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PMID:A non-radioactive method for mapping restriction fragment length polymorphic genetic markers in Anopheles gambiae. 1078 65

Intraerythrocytic survival of the malaria pathogen Plasmodium falciparum requires delivery of nutrients and disposal of waste products across the host erythrocyte membrane. Recent patch-clamp experiments have demonstrated inwardly and outwardly rectifying anion conductances in infected but not in control erythrocytes. A ClC-2-generated fraction of the inwardly rectifying current is activated by cell swelling and presumably subserves host cell volume regulation. In contrast, the outwardly rectifying current is insensitive to cell volume but allows the passage of lactate and is involved in the transport of nutrients. The present study was performed to characterize the permselectivity and pH sensitivity of the anion conductances using whole-cell recording. The outwardly rectifying and the inwardly rectifying currents exhibited permselectivities of Cl- > or = Br- approximately I- > SCN- and SCN- > I- > Br- > Cl-, respectively, as evident from the reversal potentials recorded under biionic conditions. While the inwardly rectifying current was not affected significantly by alterations of pH between 6.0 and 8.4, the outward rectifier was inhibited strongly by alkalinization to pH > or = 7.8. Fluxes of 14C-lactate and parasite growth were decreased markedly by the increase of bath pH, an effect that may at least in part be due to inhibition of the outward rectifier and subsequently impaired transport across the erythrocyte membrane.
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PMID:Permselectivity and pH-dependence of Plasmodium falciparum-induced anion currents in human erythrocytes. 1590 80

In this paper, we report a simple route to accede to a new family of C-10 fluorinated derivatives of artemisinin 7. We demonstrated that nucleophilic substitution of the allylic bromide 6 with alcohols can occur at carbon 10 (compounds 7) under solvolytic conditions (S(N)'/S(N) ratio, 87:13). Furthermore, using the particular properties of hexafluoroisopropanol (HFIP), we are able to increase the selectivity of the substitution. Primary alcohols are completely selective for allylic substitution. With amines as nucleophiles, selectivity of substitution is dependent on their nucleophilicity, but attack at carbon 16 was always favored. However, the S(N)'/S(N) ratio could be slightly increased by adding HFIP, which is able to modulate their nucleophilicity through hydrogen bonding. In preliminary in vitro assessments, these new compounds, 7, exhibited a satisfying activity against malaria.
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PMID:S(N)/S(N)' competition: selective access to new 10-fluoro artemisinins. 1659 3

Gateways to Clinical Trials are a guide to the most recent clinical trials in current literature and congresses. The data in the following tables have been retrieved from the Clinical Trials Knowledge Area of Prous Science Integrity, the drug discovery and development portal, http://integrity.prous.com. This issue focuses on the following selection of drugs: ABT-510, adalimumab, alefacept, alemtuzumab, AMG-531, anakinra, armodafinil, asenapine maleate, atazanavir sulfate, atorvastatin; Bortezomib, bosentan; CEB-1555, cetuximab, ciclesonide, clodronate, CT-011; Darifenacin hydrobromide, desloratadine; E-7010, ecallantide, eculizumab, efalizumab, eltrombopag, erlotinib hydrochloride, eslicarbazepine acetate, eszopiclone, ezetimibe; Febuxostat, fosamprenavir calcium, fulvestrant; Gefitinib, genistein; Haemophilus influenzae B vaccine, human papillomavirus vaccine; Imatinib mesylate, insulin glargine; Lenalidomide, liposomal cisplatin; MAb G250, mapatumumab, midostaurin, MP4, mycophenolic acid sodium salt; Natalizumab, neridronic acid, NSC-330507; Oblimersen sodium, ofatumumab, omalizumab, oral insulin, oregovomab; Paliperidone, parathyroid hormone (human recombinant), peginterferon alfa-2a, peginterferon alfa-2b, peginterferon alfa-2b/ribavirin, pegylated arginine deiminase 20000, pemetrexed disodium, pimecrolimus, pitavastatin, pneumococcal 7-valent conjugate vaccine, prasterone, pregabalin, pumosetrag hydrochloride; Recombinant malaria vaccine, retigabine, rivaroxaban, Ro-26-9228, romidepsin, rosuvastatin calcium, rotavirus vaccine; SGN-30, sitaxsentan sodium, solifenacin succinate, sorafenib, sunitinib malate; Tadalafil, tegaserod maleate, temsirolimus, TER-199, tifacogin, tiludronic acid, tiotropium bromide; Vildagliptin, VNP-40101M, vorinostat; YM-150, yttrium 90 (90Y) ibritumomab tiuxetan; Zanolimumab, zoledronic acid monohydrate.
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PMID:Gateways to clinical trials. 1681 Mar 45

Choline kinase is the first enzyme in the Kennedy pathway (CDP-choline pathway) for the biosynthesis of the most essential phospholipid, phosphatidylcholine, in Plasmodium falciparum. In addition, choline kinase also plays a pivotal role in trapping essential polar head group choline inside the malaria parasite. Recently, Plasmodium falciparum choline kinase (PfCK) has been cloned, overexpressed, and purified. However, the function of this enzyme in parasite growth and survival has not been evaluated owing to the lack of a suitable inhibitor. Purified recombinant PfCK enabled us to identify an inhibitor of PfCK, hexadecyltrimethylammonium bromide (HDTAB), which has a very close structural resemblance to hexadecylphosphocholine (miltefosin), the well-known antiproliferative and antileishmanial drug. HDTAB inhibited PfCK in a dose-dependent manner and offered very potent antimalarial activity in vitro against Plasmodium falciparum. Moreover, HDTAB exhibited profound antimalarial activity in vivo against the rodent malaria parasite Plasmodium yoelii (N-67 strain). Interestingly, parasites at the trophozoite and schizont stages were found to be particularly sensitive to HDTAB. The stage-specific antimalarial effect of HDTAB correlated well with the expression pattern of PfCK in P. falciparum, which was observed by reverse transcription-PCR and immunofluorescence microscopy. Furthermore, the antimalarial activity of HDTAB paralleled the decrease in phosphatidylcholine content, which was found to correlate with the decreased phosphocholine generation. These results suggest that inhibition of choline kinase by HDTAB leads to decreased phosphocholine, which in turn causes a decrease in phosphatidylcholine biosynthesis, resulting in death of the parasite.
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PMID:Inhibition of Plasmodium falciparum choline kinase by hexadecyltrimethylammonium bromide: a possible antimalarial mechanism. 1714 94

Gateways to Clinical Trials are a guide to the most recent clinical trials in current literature and congresses. The data in the following tables have been retrieved from the Clinical Trials Knowledge Area of Prous Science Integrity, the drug discovery and development portal, http://integrity.prous.com. This issue focuses on the following selection of drugs: 5-Methyltetrahydrofolate, 9-aminocamptothecin; AdPEDF.11, AE-37, albumin interferon alfa, alicaforsen sodium, alvocidib hydrochloride, AMG-706, arginine butyrate, avanafil, axitinib, azimilide hydrochloride; BAY-579352, belagenpumatucel-L, beta-lapachone, BHT-3009, BIBW-2992, bremelanotide, BX-471; Casopitant mesylate, cediranib, certolizumab pegol, CH-1504, ChimeriVax-West Nile, clofazimine, CpG-7909, curcumin, Cypher; Dapoxetine hydrochloride, darusentan, diflomotecan, D-methionine, dnaJP1, D-serine, DTPw-HB Hib-MenAC, DTPw-HepB-Hib; E-7010, ecogramostim, edodekin alfa, EGFRvlll peptide vaccine, elcometrine, elcometrine/ethinylestradiol, elsilimomab, enrasentan, ertumaxomab, etalocib sodium, exisulind; Fenretinide, fesoterodine, fingolimod hydrochloride, fontolizumab; Gefitinib, gemtuzumab ozogamicin, ghrelin (human), GV-1001; HTU-PA, human papillomavirus vaccine; Indacaterol, indiplon, interleukin-21, intranasal insulin, irinotecan hydrochloride/floxuridine, ISIS-301012, ispinesib mesylate, ixabepilone; K562/GM-CSF; Lapatinib, L-BLP-25, linezolid, liposome encapsulated paclitaxel, LY-2124275; MC-1, MC-1/lisinopril, MDX-066, melanoma vaccine, MMR-V, multivalent (ACYW) meningitis vaccine; Nilotinib, nobori, nociceptin; Oblimersen sodium, orbofiban acetate, ospemifene; Paliperidone, panitumumab, PEG-filgrastim, PEGylated interferon alfacon-1, perflubutane, pertuzumab, phenserine tartrate, phVEGF-A165, pleconaril, prasugrel, prednisolone sodium metasulfobenzoate; R-411, recombinant malaria vaccine, rhGM-CSF, roflumilast, romidepsin, ruboxistaurin mesilate hydrate; Sirolimus-eluting stent, SR-4554, St. John's Wort extract; Talabostat, Taxus, TGN-255, tifacogin, tiotropium bromide, tolevamer sodium, trabectedin, tretinoin LF; Vatalanib succinate; Yellow fever vaccine, YM-155.
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PMID:Gateways to clinical trials. 1723 18

Malaria is one of the three major serious infectious diseases in the world. As the area affected by malaria includes a large proportion of developing countries, there is a need for new antimalarials that can be synthesized and supplied inexpensively. To generate low-cost antimalarials, the MAP series 6-10, bis-cation dimers, synthesized by amidating the carboxyl group of isonicotinic acid (11) with various amines and by cationizing the nitrogen atoms of the pyridine ring with the corresponding alkyl bromides, were designed. This design enabled expansion of the structural variations of bis-cation-type antimalarial compounds. The compounds bearing alkyl or phenyl groups in the amide moieties showed remarkable antimalarial activities in vitro. Moreover, 1,1'-(1,12-dodecanediyl)bis[4-[(buthylamino)carbonyl]pyridinium bromide], MAP-412 (6 d), exhibited a potent antimalarial activity (ED(50)=8.2 mg kg(-1)). Being prepared at low cost, our bis-cation-type antimalarial compounds may be useful as lead compounds for inexpensive antimalarials.
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PMID:Antimalarial cation-dimers synthesized in two steps from an inexpensive starting material, isonicotinic acid. 1760 84


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