What's new for 'Trypanosomatids' in PubMed

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Search kinetoplastids OR kinetoplastid OR Kinetoplastida OR "trypanosoma brucei" OR leishmania OR brucei OR leishmaniasis OR "African trypanosomiasis"
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PubMed Results

Items 1 -10 of 14

1.	Cell Mol Life Sci. 2010 Feb 7. [Epub ahead of print] Apoptosis and apoptotic mimicry: the Leishmania connection. Wanderley JL, Barcinski MA. Division of Experimental Medicine, National Cancer Institute, Rio de Janeiro, Brazil. Different death-styles have been described in unicellular organisms. In most cases they evolve with phenotypic features similar to apoptotic death of animal cells, such as phosphatidylserine (PS) exposure, oligonucleosomal DNA fragmentation, and loss of mitochondrial transmembrane potential, hinting that similar mechanisms operate in both situations. However, the biochemical pathways underlying death in unicellular organisms are still unclear. Host recognition of PS exposed on the surface of unicellular parasites is an important feature of the process of infection and progression of the disease. Here, we discuss data showing that entirely different mechanisms of PS exposure co-exist during the life-cycle of Leishmania amazonensis: in the case of promastigotes, a sub-population dies by apoptosis; in the case of amastigotes, the entire population exposes PS, not necessarily followed by apoptotic death. This phenomenon has been called apoptotic mimicry. The elusive caspase-like activities described in protozoa are also discussed.
	PMID: 20140747 [PubMed - as supplied by publisher]

2.	Mem Inst Oswaldo Cruz. 2009 Dec;104(8):1191-3. Association of Lutzomyia longipalpis (Diptera: Psychodidae) population density with climate variables in Montes Claros, an area of American visceral leishmaniasis transmission in the state of Minas Gerais, Brazil. Michalsky EM, Fortes-Dias CL, França-Silva JC, Rocha MF, Barata RA, Dias ES. In the present paper, we evaluate the relationship between climate variables and population density of Lutzomyia longipalpis in Montes Claros, an area of active transmission of American visceral leishmaniasis (AVL) in Brazil. Entomological captures were performed in 10 selected districts of the city, between September 2002-August 2003. A total of 773 specimens of L. longipalpiswere captured in the period and the population density could be associated with local climate variables (cumulative rainfall, average temperature and relative humidity) through a mathematical linear model with a determination coefficient (Rsqr) of 0.752. Although based on an oversimplified statistical analysis, as far as the vector is concerned, this approach showed to be potentially useful as a starting point to guide control measures for AVL in Montes Claros.
	PMID: 20140384 [PubMed - in process]

3.	Mem Inst Oswaldo Cruz. 2009 Dec;104(8):1183-6. Effect of untreated bed nets on blood-fed Phlebotomus argentipes in kala-azar endemic foci in Nepal and India. Picado A, Kumar V, Das M, Burniston I, Roy L, Suman R, Dinesh D, Coosemans M, Sundar S, Shreekant K, Boelaert M, Davies C, Cameron M. London School of Hygiene and Tropical Medicine, London, UK. Observational studies in the Indian subcontinent have shown that untreated nets may be protective against visceral leishmaniasis (VL). In this study, we evaluated the effect of untreated nets on the blood feeding rates of Phlebotomus argentipes as well as the human blood index (HBI) in VL endemic villages in India and Nepal. The study had a 'before and after intervention' design in 58 households in six clusters. The use of untreated nets reduced the blood feeding rate by 85% (95% CI 76.5-91.1%) and the HBI by 42.2% (95% CI 11.1-62.5%). These results provide circumstantial evidence that untreated nets may provide some degree of personal protection against sand fly bites.
	PMID: 20140382 [PubMed - in process]

4.	Mem Inst Oswaldo Cruz. 2009 Dec;104(8):1181-2. The first report of the main vector of visceral leishmaniasis in America, Lutzomyia longipalpis (Lutz & Neiva) (Diptera: Psychodidae: Phlebotominae), in the state of Rio Grande do Sul, Brazil. Souza GD, Santos ED, Andrade Filho JD. Seção de Reservatórios e Vetores, Divisão de Biologia Médica, Instituto de Pesquisas Biológicas, Fundação Estadual de Produção e Pesquisa em Saúde. Visceral leishmaniasis (VL) is a widespread zoonosis in Brazil and, up to now, there has been no record of the main vector of its agent, Lutzomyia longipalpis, in the Southern Region. Due to the diagnosis of VL in a dog in October 2008 in the city of São Borja, in the southernmost Brazilian state of Rio Grande do Sul, a collection of phlebotomines was undertaken to detect the presence of the vector Lu. longipalpis. The captures were carried out with CDC light traps on three consecutive nights in 2008. A total of 39 specimens of Lu. longipalpis were captured, thereby increasing the knowledge of the geographical distribution of this important vector.
	PMID: 20140381 [PubMed - in process]

5.	Mem Inst Oswaldo Cruz. 2009 Dec;104(8):1148-58. Dispersal and survival of Nyssomyia intermedia and Nyssomyia neivai (Diptera: Psychodidae: Phlebotominae) in a cutaneous leishmaniasis endemic area of the speleological province of the Ribeira Valley, state of São Paulo, Brazil. Galati EA, Fonseca MB, Marassá AM, Bueno EF. Departamento de Epidemiologia, Faculdade de Saúde Pública, Universidade de São Paulo, São Paulo, SP, Brasil, 01246-904. The dispersal and survival of the phlebotomines Nyssomyia intermedia and Nyssomyia neivai (both implicated as vectors of the cutaneous leishmaniasis agent) in an endemic area was investigated using a capture-mark-release technique in five experiments from August-December 2003 in municipality of Iporanga, state of São Paulo, Brazil. A total of 1,749 males and 1,262 females of Ny. intermedia and 915 males and 411 females of Ny. neivai were marked and released during the five experiments. Recapture attempts were made using automatic light traps, aspiration in natural resting places and domestic animal shelters and Shannon traps. A total of 153 specimens (3.48%) were recaptured: 2.59% (78/3,011) for Ny. intermedia and 5.35% (71/1,326) for Ny. neivai. Both species were recaptured up to 144 h post-release, with the larger part of them recaptured within 48 h. The median dispersion distances for Ny. intermedia and Ny. neivai, respectively, were 109 m and 100 m. The greatest dispersal range of Ny. intermedia was 180 m, while for Ny. neivai one female was recaptured in a pasture at 250 m and another in a pigsty at 520 m, showing a tendency to disperse to more open areas. The daily survival rates calculated based on regressions of the numbers of marked insects recaptured on the six successive days after release were 0.746 for males and 0.575 for females of Ny. intermedia and 0.649 for both sexes of Ny. neivai. The size of the populations in the five months ranged from 8,332-725,085 for Ny. intermedia males, 2,193-104,490 for Ny. intermedia females, 1,687-350,122 for Ny. neivai males and 254-49,705 for Ny. neivai females.
	PMID: 20140376 [PubMed - in process]

6.	Braz J Infect Dis. 2009 Apr;13(2):83-5. Biochemical association between essential trace elements and susceptibility to Leishmania major in BALB/c and C57BL/6 mice. Amini M, Nahrevanian H, Khatami S, Farahmand M, Mirkhani F, Javadian S. Tehran Center, Payame Nour University. Several enzymes that contribute to immune system responses require zinc and copper as trace elements for their activity. We examined zinc and copper levels in two susceptible Balb/c mouse lines and resistant C57bl/6 mice infected with Leishmania major MRHO/IR/75/ER, a prevalent strain that causes cutaneous leishmaniasis in Iran. Serum Zn and Cu were determined by flame atomic absorption spectrophotometry. Higher Cu levels were found in infected C57bl/6 mice and higher Zn levels were found in infected Balb/c mice. Also, Cu/Zn ratios were increased in both the Balb/c and the C57bl/6 mice. We conclude that concentrations of essential trace elements vary during cutaneous leishmaniasis infection and that this variation is associated with susceptibility/resistance to Leishmania major in Balb/c and C57bl/6 mice. We detected Zn deficiency in the plasma of infected Balb/c mice; possibly, therapeutic administration of Zn would be useful for treating this form of leishmaniasis. Increases in Cu level might increase resistance to leishmaniasis. Based on our findings, the Cu/Zn ratio could be a useful marker for the pathophysiology of leishmaniasis.
	PMID: 20140348 [PubMed - in process]

7.	PLoS Pathog. 2010 Feb 5;6(2):e1000755. Neutrophil-Derived CCL3 Is Essential for the Rapid Recruitment of Dendritic Cells to the Site of Leishmania major Inoculation in Resistant Mice. Charmoy M, Brunner-Agten S, Aebischer D, Auderset F, Launois P, Milon G, Proudfoot AE, Tacchini-Cottier F. Department of Biochemistry, WHO Immunology Research and Training Center, University of Lausannne, Epalinges, Switzerland. Neutrophils are rapidly and massively recruited to sites of microbial infection, where they can influence the recruitment of dendritic cells. Here, we have analyzed the role of neutrophil released chemokines in the early recruitment of dendritic cells (DCs) in an experimental model of Leishmania major infection. We show in vitro, as well as during infection, that the parasite induced the expression of CCL3 selectively in neutrophils from L. major resistant mice. Neutrophil-secreted CCL3 was critical in chemotaxis of immature DCs, an effect lost upon CCL3 neutralisation. Depletion of neutrophils prior to infection, as well as pharmacological or genetic inhibition of CCL3, resulted in a significant decrease in DC recruitment at the site of parasite inoculation. Decreased DC recruitment in CCL3(-/-) mice was corrected by the transfer of wild type neutrophils at the time of infection. The early release of CCL3 by neutrophils was further shown to have a transient impact on the development of a protective immune response. Altogether, we identified a novel role for neutrophil-secreted CCL3 in the first wave of DC recruitment to the site of infection with L. major, suggesting that the selective release of neutrophil-secreted chemokines may regulate the development of immune response to pathogens.
	PMID: 20140197 [PubMed - as supplied by publisher]

8.	J Antibiot (Tokyo). 2010 Feb 5. [Epub ahead of print] Anti-leishmanial activity of betulin derivatives. Alakurtti S, Bergström P, Sacerdoti-Sierra N, Jaffe CL, Yli-Kauhaluoma J. [1] Faculty of Pharmacy, Division of Pharmaceutical Chemistry, University of Helsinki, Helsinki, Finland [2] VTT Technical Research Centre of Finland, Espoo, Finland. Leishmanicidal activity of 24 derivatives of naturally occurring and abundant triterpenes belonging to the lupane series, betulin, betulinic acid and betulonic acid, is described in this study. The easily modified positions of the lupane skeleton, the hydroxy groups of C-3 and C-28, as well as the carbon-carbon double bond C-20-C-29 were used as a starting point to prepare a library of triterpenoid derivatives for bioactivity studies. The compounds were evaluated against Leishmania donovani axenic amastigotes on a microplate assay at 50 muM. GI(50) values of the most effective compounds were evaluated, as well as their cytotoxicity on the human macrophage cell line THP-1, and anti-leishmanial activity against L. donovani-infected THP-1 macrophages was determined. Betulonic acid was the most potent derivative, yielding a GI(50) value of 14.6 muM. Promising and distinct structure-activity relationships were observed, and these compounds can be regarded as significant lead molecules for further improvement and optimization.The Journal of Antibiotics advance online publication, 5 February 2010; doi:10.1038/ja.2010.2.
	PMID: 20139867 [PubMed - as supplied by publisher]

9.	J Immunol. 2010 Feb 5. [Epub ahead of print] Therapeutic Glucocorticoid-Induced TNF Receptor-Mediated Amplification of CD4+ T Cell Responses Enhances Antiparasitic Immunity. Haque A, Stanley AC, Amante FH, Rivera FD, Zhou Y, Kuns RD, Yardley V, Sakaguchi S, Hill GR, Engwerda CR. Immunology and Infection Laboratory, Queensland Institute of Medical Research and The Australian Center for Vaccine Development; Chronic infectious diseases and cancers are often associated with suboptimal effector T cell responses. Enhancement of T cell costimulatory signals has been extensively studied for cancer immunotherapy but not so for the treatment of infectious disease. The few previous attempts at this strategy using infection models have lacked cellular specificity, with major immunoregulatory mechanisms or innate immune cells also being targeted. In this study, we examined the potential of promoting T cell responses via the glucocorticoid-induced TNF receptor (GITR) family-related protein in a murine model of visceral leishmaniasis. GITR stimulation during established infection markedly improved antiparasitic immunity. This required CD4(+) T cells, TNF, and IFN-gamma, but crucially, was independent of regulatory T (Treg) cells. GITR stimulation enhanced CD4(+) T cell expansion without modulating Treg cell function or protecting conventional CD4(+) T cells from Treg cell suppression. GITR stimulation substantially improved the efficacy of a first-line visceral leishmaniasis drug against both acute hepatic infection and chronic infection in the spleen, demonstrating its potential to improve clinical outcomes. This study identifies a novel strategy to therapeutically enhance CD4(+) T cell-mediated antiparasitic immunity and, importantly, achieves this goal without impairment of Treg cell function.
	PMID: 20139272 [PubMed - as supplied by publisher]

10.	Exp Parasitol. 2010 Feb 4. [Epub ahead of print] Transovarial passage of Leishmania infantum kDNA in artificially infected Rhipicephalus sanguineus. Dantas-Torres F, Martins TF, de Paiva-Cavalcanti M, Figueredo LA, Lima BS, Brandão-Filho SP. Dipartimento di Sanità Pubblica e Zootecnia, Università degli Studi di Bari, Valenzano, BA, Italy. Phlebotomine sand flies are the only proven biological vectors of Leishmania parasites. However, Rhipicephalus sanguineus ticks have long been suspected to transmit Leishmania infantum in studies carried out in laboratory and natural conditions. In the present study, 5 mul of L. infantum promastigotes (1 x 10(6) cells per ml) was injected into the hemocel through the coxa I of four engorged females (F1, F2, F3 and F4). Control ticks (F5 and F6) were injected with sterile phosphate-buffered saline (PBS) using the same procedure. Then, these females, their eggs, and the originated larvae were tested by real time polymerase chain reaction (real-time PCR) for the presence of L. infantum kinetoplast DNA (kDNA). Females and eggs were tested after the end of the oviposition period (about five weeks post-inoculation) whereas larvae were tested about four months after the inoculation of females. All artificially infected females were positive for L. infantum kDNA. In addition, two pools of eggs (one from F2 and other from F4) and four pools of larvae (one from each F1 and F4 and two from F2) were positive for L. infantum kDNA. These results showed, for the first time, the transovarial passage of L. infantum kDNA in R. sanguineus ticks, thus suggesting that the transovarial transmission of L. infantum protozoa in ticks is worth to be investigated. Copyright © 2010. Published by Elsevier Inc.
	PMID: 20138871 [PubMed - as supplied by publisher]