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Sent on Wednesday, 2011 Apr 27Search kinetoplastids OR kinetoplastid OR Kinetoplastida OR "trypanosoma brucei" OR leishmania OR brucei OR leishmaniasis OR "African trypanosomiasis"
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| PubMed Results |
| 1. | Phytother Res. 2011 May;25(5):778-83. doi: 10.1002/ptr.3330. Epub 2010 Nov 12.Evaluation of Turkish seaweeds for antiprotozoal, antimycobacterial and cytotoxic activities.Süzgeç-Selçuk S, Meriçli AH, Güven KC, Kaiser M, Casey R, Hingley-Wilson S, Lalvani A, Tasdemir D.SourceDepartment of Pharmacognosy, Faculty of Pharmacy, University of Istanbul, 34116 Beyazıt, Istanbul, Turkey. AbstractAs part of our continuing research on seaweeds, crude MeOH extracts of two green, three brown and six red algae collected from Marmara, Black, Aegean and Mediterranean Seas were screened. Four parasitic protozoa, i.e. Plasmodium falciparum, Trypanosoma brucei rhodesiense, T. cruzi, Leishmania donovani and the tubercle bacillus Mycobacterium tuberculosis were used as test organisms for the in vitro assays. The selective toxicity of the extracts was also determined against mammalian L6 cells. All seaweed extracts were active against T. brucei rhodesiense; the Dasya pedicellata extract was the most potent (IC(50) value 0.37 µg/mL). The same extract also weakly inhibited the growth of T. cruzi (IC(50) 62.02 µg/mL). All seaweed extracts also showed leishmanicidal activity (IC(50) values 16.76-69.98 µg/mL). The majority of the extracts also exhibited antiplasmodial potential and the most potent extracts were those from D. pedicellata (IC(50) 0.38 µg/mL), Codium bursa (IC(50) 1.38 µg/mL) and Caulerpa rasemosa (IC(50) 3.12 µg/mL). One brown and two red algal extracts showed some weak activity against Mycobacterium tuberculosis (MIC values 125-256 µg/mL). Except for the extract of Dasya pedicellata, none of the extracts displayed any cytotoxicity. This is the second study investigating the antiprotozoal activities of Turkish marine algae and identifies Dasya pedicellata, an understudied algal species, as a candidate for further studies. Copyright © 2010 John Wiley & Sons, Ltd. Copyright © 2010 John Wiley & Sons, Ltd. |
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| 2. | Cad Saude Publica. 2011 Mar;27(3):603-7.Canine visceral leishmaniasis in the Krenak indigenous community, Resplendor, Minas Gerais State, Brazil, 2007.Antônio EG, Malacco MA, Gontijo CM, Moreira EF, Caldas IS, Pena JL, Machado-Coelho GL.SourceUniversidade Vale do Rio Doce, Governador Valadares, Brasil. AbstractThe authors conducted a cross-sectional study of the local canine population in the Krenak indigenous community to detect parasites of the genus Leishmania and identify the circulating species and the proportion of asymptomatic dogs, while investigating associations between canine infection and the dogs' sex, age, and hair length. A seroepidemiological survey was performed, including 63 dogs. All the animals underwent clinical examination to verify the presence of characteristic signs, and serum samples were taken for serological tests (ELISA, IIF). Infected dogs culled by the health service were necropsied and the material was analyzed using molecular diagnostic techniques. The cross-sectional study detected a 46% prevalence rate, and the circulating species was Leishmania (L.) chagasi. The statistical analysis showed no association between infection and the independent variables. The study generated data on the epidemiological situation with canine infection in the area, which was previously unknown. |
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| 3. | Infect Immun. 2011 Apr 25. [Epub ahead of print]Leishmania-infected macrophages are targets of NK cell-derived cytokines, but not of NK cell cytotoxicity.Prajeeth CK, Haeberlein S, Sebald H, Schleicher U, Bogdan C.SourceMikrobiologisches Institut - Klinische Mikrobiologie, Immunologie und Hygiene, Friedrich-Alexander-Universität Erlangen-Nürnberg and Universitätsklinikum Erlangen, Erlangen, Germany. AbstractNatural killer (NK) cells are important components of a protective immune response against intracellular pathogens such as Leishmania parasites which reside within myeloid cells. Previous in vivo studies in murine cutaneous or visceral leishmaniasis showed that NK cells are activated by conventional dendritic cells in a TLR9-, IL-12- and IL-18-dependent manner during the early phase of infection and help to restrict the tissue parasite burden by unknown mechanisms. Here, we tested whether NK cells contribute to the control of Leishmania infections by lysing or by activating infected host cells. Co-culture experiments revealed that activated NK cells from poly(I:C)-treated mice readily killed tumor target cells, whereas L. infantum- or L. major-infected macrophages or dendritic cells remained viable. Infection with Leishmania did not significantly alter the expression of NK cell-activating (Rae1α, MULT-1, CD48) or inhibitory molecules (MHC class I, Qa-1) on the surface of myeloid cells, which offers an explanation for their protection from NK cell cytotoxicity. Consistent with these in vitro data, in vivo cytotoxicity assays revealed poor cytolytic activity of NK cells against adoptively transferred infected wild-type macrophages, whereas MHC class I-deficient macrophages were efficiently eliminated. NK cells activated by IL-12 and IL-18 stimulated macrophages to kill intracellular Leishmania in a cell contact-independent, but IFN-γ-, TNF- and iNOS-dependent manner. We conclude that Leishmania parasites, unlike viruses, do not render infected myeloid cells susceptible to the cytotoxicity of NK cells. Instead, soluble products of NK cells trigger the leishmanicidal activity of macrophages. |
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| 4. | Infect Immun. 2011 Apr 25. [Epub ahead of print]Toll-like receptors participate in macrophage activation and intracellular control of Leishmania (Viannia) panamensis.Gallego C, Golenbock D, Gomez MA, Saravia N.SourceCentro Internacional de Entrenamiento e Investigaciones Medicas-CIDEIM, Cali- Colombia. AbstractToll-like receptors (TLRs) play a central role in macrophage activation and control of parasitic infections. Their contribution to the outcome of Leishmania infection is just beginning to be deciphered. We examined the interaction of Leishmania panamensis with TLRs in the activation of host macrophages. L. panamensis infection resulted in up-regulation of TLR1, TLR2, TLR3 and TLR4 expression, and induced TNFα secretion by human primary macrophages at comparable levels and kinetics as specific TLR ligands. The TLR-dependence of the host cell response was substantiated by the absence of TNFα production in MyD88/TRIF(-/-) murine bone marrow derived macrophages and mouse macrophage cell lines in response to promastigotes and amastigotes. Systematic screening of TLR-deficient macrophages revealed that TNFα production was completely abrogated in TLR4(-/-) macrophages, consistent with the increased intracellular parasite survival at early time points of infection. TNFα secretion was significantly reduced in macrophages lacking endosomal TLRs, but was unaltered by lack of TLR2 or MD-2. Together, these findings support the participation of TLR4 and endosomal TLRs in the activation of host macrophages by L. panamensis and in the early control of infection. |
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| 5. | Parasitology. 2011 Apr 26:1-8. [Epub ahead of print]Immuno-enzymatic evaluation of the recombinant TSSA-II protein of Trypanosoma cruzi in dogs and human sera: a tool for epidemiological studies.Cimino RO, Rumi MM, Ragone P, Lauthier J, Alberti D'Amato A, Quiroga IR, Gil JF, Cajal SP, Acosta N, Juárez M, Krolewiecki A, Orellana V, Zacca R, Marcipar I, Diosque P, Nasser JR.SourceCátedra de Química Biológica, Facultad de Ciencias Naturales. Universidad Nacional de Salta, Av. Bolivia 5150, Salta (4400), Argentina. AbstractSUMMARYThe rTSSA-II (recombinant Trypomastigote Small Surface II) antigen was evaluated by ELISA to detect anti-Trypanosoma cruzi antibodies in sera from naturally infected dogs and humans. For this evaluation ELISA-rTSSA-II was standardized and groups were classified according to the results obtained through xenodiagnosis, ELISA and PCR. Sensitivity (Se), Specificity (Sp), Kappa index (KI) and area under curve (AUC) were determined. The Se was determined by using 14 sera from dogs infected with T. cruzi VI (TcVI) whereas Sp was determined by using 95 non-chagasic sera by xenodiagnosis, ELISA-Homogenate and PCR. The performance of ELISA-rTSSA-II in dog sera was high (AUC=0·93 and KI=0·91). The Se was 92·85% (1 false negative) and Sp was 100%. Two sera from dogs infected with TcI and 1 with TcIII were negative. For patients infected with T. cruzi, reactivity was 87·8% (36/41), there was only 1 indeterminate, and Sp was 100%. Fifty-four sera from non-chagasic and 68 sera from patients with cutaneous leishmaniasis did not react with rTSS-II. ELISA-rTSSA-II showed a high performance when studying sera from naturally infected dogs and it also presented 100% Sp. This assay could be an important tool to carry out sero-epidemiological surveys on the prevalence of T. cruzi circulating lineages in the region. |
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| 6. | Scand J Immunol. 2011 Apr 23. doi: 10.1111/j.1365-3083.2011.02566.x. [Epub ahead of print]The influence of low oxygen on macrophage response to Leishmania infection.Degrossoli A, Arrais-Silva WW, Colhone MC, Gadelha FR, Joazeiro PP, Giorgio S.SourceDepartment of Animal Biology, Biology Institute, Universidade Estadual de Campinas, Caixa Postal 6109, 13083-970, Campinas, São Paulo, Brazil. Departament of Biochemistry, Biology Institute, Universidade Estadual de Campinas. Departament of Histology and Embriology, Biology Institute, Universidade Estadual de Campinas. AbstractHypoxia (low oxygen tension) is a common feature of inflamed and infected tissues. The influence of hypoxia on macrophage responses to microorganisms has only recently been studied. This study demonstrates that hypoxia induced macrophages to control Leishmania amazonensis, an intracellular parasite which causes cutaneous and cutaneous metastatic lesions. The mechanisms which contribute to the control of macrophages against L. amazonensis infection under a hypoxic microenvironment are not known. Nitric oxide, TNF-α, IL-10 or IL-12 are not responsible for the decrease in parasitism under hypoxia. Live L. amazonensis entry or exocytoses of internalized particles as well as energetic metabolism were not impaired in infected macrophages; no apoptosis-like death was detected in intracellular parasites. Reactive oxygen species (ROS) is likely to be involved, since treatment with antioxidants N-acetylcysteine (NAC) and ebselen inhibit the leishmanicidal effect of macrophages under hypoxia. L. amazonensis infection induces macrophages to express hypoxia-inducible factor-1 (HIF-1α) and -2 (HIF-2α). Data indicate that hypoxia affects the microbial activities and protein expression of macrophages leading to a different phenotype from that of the normoxic counterpart, and that it plays a role in modulating Leishmania infection. Copyright © 2011 Blackwell Publishing Ltd. |
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