Publications
| Title | Abstract | Year Filter | PMID(sorted descending) Filter |
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| l-arginine and cationic amino acid transporter 2b regulate growth and survival of leishmania amazonensis amastigotes in macrophages. | leishmania spp. are obligate intracellular parasites, requiring a suitable microenvironment for their growth within host cells. we previously reported that the growth of leishmania amazonensis amastigotes in murine macrophages (mphis) was enhanced in the presence of gamma interferon (ifn-gamma), a th1 cytokine normally associated with classical mphi activation and killing of intracellular pathogens. in this study, we provided several lines of evidence suggesting that ifn-gamma-mediated parasite ... | 2007 | 17387163 |
| leishmania amazonensis trypanothione reductase: evaluation of the effect of glutathione analogs on parasite growth, infectivity and enzyme activity. | trypanothione reductase (tr) is a major enzyme in trypanosomatids. its substrate, trypanothione is a molecule containing a tripeptide (l-glutamic acid-cysteine-glycine) coupled to a polyamine, spermidine. this redox system (tr/trypanothione) is vital for parasite survival within the host cell and has been described as a good target for chemotherapy anti-leishmania. the use of tripeptides analogs of glutathione would result in a decrease in trypanothione synthesis and as a consequence in tr activ ... | 2007 | 17373550 |
| first report of diffuse cutaneous leishmaniasis and leishmania amazonensis infection in rio de janeiro state, brazil. | diffuse cutaneous leishmaniasis (dcl) is characterised by multiple and progressive cutaneous lesions, resistance to chemotherapy and leishmania-specific t-cell anergy. we report the first autochthonous dcl case and the first human infection with leishmania amazonensis in rio de janeiro state, brazil, where only l. braziliensis is considered to be the causative agent of cutaneous leishmaniasis. leishmania amazonensis was identified by multilocus enzyme electrophoresis and pcr-rflp. our case was d ... | 2007 | 17368698 |
| a comparative study of mesoionic compounds in leishmania sp. and toxicity evaluation. | in this first study, a series of mesoionic compounds like 1,3,4-thiadiazolium-2-phenylamine derivatives were synthesized and studied in leishmania amazonensis. the cytotoxic effects of these compounds on the host cells were investigated and the antileishmanial in vitro activity was compared with other species of leishmania (leishmania chagasi and leishmania braziliensis). the compounds presented lower toxicity in murine macrophages than the reference drug pentamidine. the halogen derivatives 5, ... | 2007 | 17367894 |
| [role of the parasitophorous vacuole of murine macrophages infected with leishmania amazonensis in molecule acquisition]. | leishmania are intracellular parasites of macrophages, confined into compartments known as parasitophorous vacuoles. the permeability of this compartment depends on its interaction with the endocytic pathway and transport proteins present on its membrane. | 2006 | 17361839 |
| leishmania amazonensis: humoral response to amastigote excreted-antigens in murine leishmaniasis. | with the purpose of studying the antigenic role that factors excreted by leishmania amastigotes might have during murine infection, immunoblots were carried out with sera from c57bl/6 and balb/c mice infected with two strains of leishmania (l.) amazonensis, nr and ifla/br. both strains differ widely in virulence in balb/c mice. balb/c but not c57bl/6 sera recognized several excretion products. the excreted antigens showed a strong response towards igg1 and igg2a isotypes whilst they reacted only ... | 2007 | 17349625 |
| leishmania amazonensis: anionic currents expressed in oocytes upon microinjection of mrna from the parasite. | transport mechanisms involved in ph homeostasis are relevant for the survival of leishmania parasites. the presence of chloride conductive pathways in leishmania has been anticipated since anion channel inhibitors limit the proton extrusion mediated by the h+atpase, which is the major regulator of intracellular ph in amastigotes. in this study, we used xenopus laevis oocytes as a heterologous expression system in which to study the expression of ion channels upon microinjection of polya mrna fro ... | 2007 | 17328895 |
| leishmania amazonensis: multiple receptor-ligand interactions are involved in amastigote infection of human dendritic cells. | in their mammalian hosts, leishmania are obligate intracellular parasites that reside in macrophages and dendritic cells (dcs). in the present study, we have investigated in vitro the mechanisms of entry into human dcs of leishmania amazonensis amastigotes isolated from lesions in nude mice (am nude). the dc infection rate with am nude was approximately 36%, while opsonization of am nude with normal human serum and infected human serum increased the dc infection rates to 60% and 62%, respectivel ... | 2007 | 17320869 |
| resistance of leishmania (leishmania) amazonensis and leishmania (viannia) braziliensis to nitric oxide correlates with disease severity in tegumentary leishmaniasis. | nitric oxide (no*) plays a pivotal role as a leishmanicidal agent in mouse macrophages. no* resistant escherichia coli and mycobacterium tuberculosis have been associated with a severe outcome of these diseases. | 2007 | 17316450 |
| loop 1 structure of the leishmanial icam-l molecule is crucial for parasite binding and infection of host macrophages. | the binding of each intercellular adhesive molecule (icam) molecule fragment from leishmania amazonensis (icam-l) to host macrophages was investigated using an indirect immunofluorescent sandwich technique, based on the observation that icam-l can block the uptake of l. amazonensis on the macrophage surface and all prepared icam-l fragments can react with rabbit anti-icam-l antiserum. the icam-l fragments lacking the loop 1 (li) structure failed to bind to macrophages, and the disruption of the ... | 2007 | 17306804 |
| leishmanicidal activity of a supercritical fluid fraction obtained from tabernaemontana catharinensis. | the branches and leaves of tabernaemontana catharinensis were extracted with supercritical fluid using a mixture of co(2) plus ethanol (sfe), and the indole alkaloid enriched fraction (af3) was selected for anti-leishmania activity studies. we found that af3 exhibits a potent effect against intracellular amastigotes of leishmania amazonensis, a causative agent of new world cutaneous leishmaniasis. af3 inhibits leishmania survival in a dose-dependent manner, and reached 88% inhibition of amastigo ... | 2007 | 17306614 |
| the ultrastructure of the parasitophorous vacuole formed by leishmania major. | protozoan parasites of leishmania spp. invade macrophages as promastigotes and differentiate into replicative amastigotes within parasitophorous vacuoles. infection of inbred strains of mice with leishmania major is a well-studied model of the mammalian immune response to leishmania species, but the ultrastructure and biochemical properties of the parasitophorous vacuole occupied by this parasite have been best characterized for other species of leishmania. we examined the parasitophorous vacuol ... | 2006 | 17304790 |
| interferon-gamma is required for the late but not early control of leishmania amazonensis infection in c57bl/6 mice. | the critical role of interferon-gamma (ifn-gamma) in the resistance of c57bl/6 mice to leishmania major is widely established but its role in the relative resistance of these animals to l. amazonensis infection is still not clear. in this work we use c57bl/6 mice congenitally deficient in the ifn-gamma gene (ifn-gamma ko) to address this issue. we found that ifn-gamma ko mice were as resistant as their wild-type (wt) counterparts at least during the first two months of infection. afterwards, whe ... | 2007 | 17294004 |
| activity of brazilian and bulgarian propolis against different species of leishmania. | extracts of propolis samples collected in brazil and bulgaria were assayed against four leishmania species--leishmania amazonensis, l. braziliensis, l. chagasi from the new world, and l. major from the old world--associated to different clinical forms of leishmaniasis. the composition of the extracts has been previously characterized by high temperature high resolution gas chromatography coupled to mass spectrometry. considering the chemical differences among the extracts and the behavior of the ... | 2007 | 17294003 |
| intracellular leishmania: your iron or mine? | iron is a co-factor for several essential enzymes and biochemical pathways, including those required for replication of pathogens such as leishmania in macrophages. iron acquisition is emerging as a key battleground in which the iron import systems of microbes are pitted against the iron withdrawal and sequestration systems of macrophages, with both competing for iron at the interface of host-pathogen interaction. the recent characterization of a ferrous iron transport system (lit1) in leishmani ... | 2007 | 17257847 |
| activity, toxicity and analysis of resistance of essential oil from chenopodium ambrosioides after intraperitoneal, oral and intralesional administration in balb/c mice infected with leishmania amazonensis: a preliminary study. | the world health organization has classified the leishmaniasis as a major tropical disease. current therapy is toxic, expensive and cause several adverse effects. the majority of people in endemic areas of leishmaniasis depend of natural and traditional medicine. this study was developed to examine the activity of the essential oil from chenopodium ambrosioides in balb/c mice infected with leishmania amazonensis. the infected animals received two cycle of treatment by different routes (intraperi ... | 2007 | 17254746 |
| effect of l-leucine methyl ester on growth and ultrastructure of trypanosoma cruzi. | l-amino acid methyl esters, such as l-leucine methyl ester (leu-ome), have been identified as agents targeting the lysosomal system of leishmania amazonensis amastigotes, by a mechanism that involves ester hydrolysis by parasite enzymes located inside megasomes. we have here analyzed the effect of leu-ome on all three evolutive forms of trypanosoma cruzi, in a search for potential targets of the compound in this protozoan. treatment of epimastigote forms resulted in dose-dependent growth inhibit ... | 2007 | 17250794 |
| inhibition of leishmania (leishmania) amazonensis growth and infectivity by aureobasidin a. | to study the effect of aureobasidin a, an inhibitor of inositol phosphorylceramide (ipc) synthase, on leishmania growth and infectivity. | 2007 | 17242034 |
| comparative study of the efficacy of formulations containing fluconazole or paromomycin for topical treatment of infections by leishmania (leishmania) major and leishmania (leishmania) amazonensis. | the development of alternative therapeutic approaches for cutaneous leishmaniasis (cl) has received considerable attention in recent research, including the identification of formulations for topical treatment. in the present study, the activity of two formulations was evaluated in balb/c mice experimentally infected with either leishmania (leishmania) major or l. (l.) amazonensis, a hydrophilic gel containing 10% paromomycin (pahg) and a cream containing 1% fluconazole (fluc). after development ... | 2007 | 17206508 |
| activation of the mapk, erk, following leishmania amazonensis infection of macrophages. | il-10 is a critical cytokine in determining host susceptibility to leishmania spp. we previously demonstrated that macrophage-derived il-10 could contribute to disease exacerbation, but the mechanisms whereby leishmania infections led to il-10 induction were not fully understood. in this study, we demonstrated that infection of macrophages with leishmania amazonensis amastigotes led to the activation of the mapk, erk1/2. this activation was required, but not sufficient for il-10 induction. in ad ... | 2007 | 17202371 |
| leishmania amazonensis infections in oryzomys acritus and oryzomys nitidus from bolivia. | three of thirteen oryzomys acritus, emmons and patton 2005 (rodentia: muridae: sigmodontinae) and 3 of 17 oryzomys nitidus, thomas 1884, collected from noël kempff national park, bolivia, from 2002 to 2005, tested positive for leishmania (leishmania) amazonensis or l. (l.) mexicana and negative for leishmania (viannia) spp. using the polymerase chain reaction (pcr). based on previous records of l. (l.) amazonensis in humans, rodents, and sand flies from bolivia, and the geographic distributions ... | 2006 | 17172367 |
| synthesis and biological evaluation of some 6-substituted purines. | we report herein the synthesis and the in vitro antileishmanial evaluation of a series of 6-substituted purines. the most active compounds against leishmania amazonensis promastigotes were 6-(3'-chloropropylthio)purine 2 (d.a. benson, i. karsch-mizrachi, d.j. lipman, j. ostell, b.a. rapp, d.l. wheeler, genbank. nucleic acids res. 28 (2000) 15-18; e.v. aleksandrova, p.m.i.e. valashek, j. med. pharm. chem. 35 (2001) 172-173), 6-(3'-(thioethylamine)propylthio)purine 5, 6-(alpha-aceticacidthio)purin ... | 2007 | 17156894 |
| trypanosoma cruzi oleate desaturase: molecular characterization and comparative analysis in other trypanosomatids. | trypanosoma cruzi lipids contain a high content of unsaturated fatty acids, primarily oleic acid (c18:1) and linoleic acid (c18:2). previous data suggest that this parasite is able to convert oleic acid into linoleic acid; humans are not able to do this. presently, we show that t. cruzi has a gene with high similarity to the delta12 (omega6)-oleate desaturase from plants. northern blot analysis of the oleate desaturase gene from t. cruzi (od(tc)) indicated that this gene is transcribed in epimas ... | 2006 | 17152952 |
| lactobacillus delbrueckii as a potential skin adjuvant for induction of type 1 immune responses. | we evaluated the ability of lactobacillus delbrueckii ufv h2b20, a probiotic candidate, to stimulate the production of inflammatory cytokines and to induce macrophage activation and th1 differentiation in peripheral blood mononuclear cells (pbmc) from healthy volunteers. our results show that pbmc stimulated with heat-killed lact. delbrueckii produced elevated levels of il-12, ifn-gamma and tnf-alpha but no il-10. ifn-gamma production was il-12 dependent with nk cells as the main source. further ... | 2007 | 17127382 |
| [detection of p-4 and gp-46 expression in leishmania amazonensis amastigotes and promastigotes by rt-pcr]. | to detect the expression level of stage-specific genes in leishmania promastigotes and amastigotes. | 2006 | 17094595 |
| configuration and leishmanicidal activity of (-)-argentilactone epoxides. | epoxidation of argentilactone (1) with m-chloroperbenzoic acid gave a diasteromeric mixture of 2 and 3 in a ratio 1.8 : 1, with total yield 60%. the configuration of 7,8-oxirane ring for both diasteromers was determined by nmr analysis. reaction of 1 with urea hydrogen peroxide gave the 3,4-epoxide (4) in 65% yield. the in vitro activity of 2, 3, 4 and argentilactone against leishmania amazonensis was tested, only epoxides (2) and (3) showed leishmanicidal effect. | 2006 | 17050183 |
| synthesis, analytical behaviour and biological evaluation of new 4-substituted pyrrolo[1,2-a]quinoxalines as antileishmanial agents. | an original series of 4-substituted pyrrolo[1,2-a]quinoxaline derivatives, new structural analogues of galipea species quinoline alkaloids, was synthesized from various substituted 2-nitroanilines via multistep heterocyclizations and tested for in vitro antiparasitic activity upon leishmania amazonensis and leishmania infantum strains. structure-activity relationships enlighten the importance of the 4-substituted alkenyl side chain on the pyrrolo[1,2-a]quinoxaline moiety to modulate the antileis ... | 2007 | 17049253 |
| leishmania mexicana amazonensis: development of a peptide tag useful for labeling and purifying biotinylated recombinant proteins. | a number of peptide tags are available to facilitate the characterization of recombinant proteins. we have tested the bacterial oxaloacetate decarboxylase biotinylation domain for its efficacy in tagging recombinant proteins in vivo in leishmania. to achieve efficient biotinylation, leishmania also had to be co-transformed with the gene for bacterial biotin protein ligase (bira gene product). the recombinant chimeric protein could be detected on blots probed with avidin-horseradish peroxidase an ... | 2007 | 17027004 |
| high selective leishmanicidal activity of 3-hydroxy-2-methylene-3-(4-bromophenyl)propanenitrile and analogous compounds. | sixteen not new aromatic compounds were prepared by one-pot reaction i.e. through baylis-hillman reaction and were the first time evaluated against promastigote leishmania amazonensis and infected mammalian cells. most of the compounds were selectively more active against amastigotes than the reference drug sodium stibogluconate (pentostam, ic(50)=44.7 microm). we found that 3-hydroxy-2-methylene-3-(4-bromophenyl) propanenitrile (13) was the most active (ic(50)=12.5 microm) and safer compound (0 ... | 2007 | 17010481 |
| a leishmania amazonensis zip family iron transporter is essential for parasite replication within macrophage phagolysosomes. | infection of mammalian hosts with leishmania amazonensis depends on the remarkable ability of these parasites to replicate within macrophage phagolysosomes. a critical adaptation for survival in this harsh environment is an efficient mechanism for gaining access to iron. in this study, we identify and characterize lit1, a novel l. amazonensis membrane protein with extensive similarity to irt1, a zip family ferrous iron transporter from arabidopsis thaliana. the ability of lit1 to promote iron tr ... | 2006 | 17000865 |
| cxcl10/gamma interferon-inducible protein 10-mediated protection against leishmania amazonensis infection in mice. | leishmania amazonensis can cause progressive disease in most inbred strains of mice. we have previously shown that l. amazonensis-infected c57bl/6 mice have profound impairments in expression of proinflammatory cytokines and chemokines and in activation of antigen-specific cd4(+) t cells. these impairments are independent of interleukin-4 (il-4) but partially due to il-10 production. the precise mechanism of pathogenesis associated with l. amazonensis infection remains largely unresolved. since ... | 2006 | 16982826 |
| platelet activating factor receptor-deficient mice present delayed interferon-gamma upregulation and high susceptibility to leishmania amazonensis infection. | we investigated the role of the platelet activation factor (paf) receptor (pafr) in the outcome of infection with leishmania amazonensis. pafr deficient (pafr(-/-)) mice were infected with l. amazonensis and the course of infection was followed. we found that pafr(-/-) mice in the c57bl/6 background were more susceptible to infection with l. amazonensis than the wild-type controls, as seen both by lesion size and parasite number at the site of infection. interferon (ifn)-gamma production was del ... | 2006 | 16938478 |
| soluble factors from leishmania major-specific cd4+t cells and b cells limit l. amazonensis amastigote survival within infected macrophages. | in contrast to l. major, the factors required for clearance of leishmania amazonensis parasites from infected macrophages have been difficult to define. multiple studies have made progress towards identifying the phenotypic differences in various cell types secondary to l. amazonensis infection as compared to l. major infection, but few have shown the cell types or factors required for parasite clearance. based on studies which identified that mice previously infected with l. major and healed ca ... | 2006 | 16934514 |
| leukotrienes are essential for the control of leishmania amazonensis infection and contribute to strain variation in susceptibility. | leukotrienes (lts) are known to be produced by macrophages when challenged with leishmania, but it is not known whether these lipid mediators play a role in host defense against this important protozoan parasite. in this study, we investigated the involvement of lts in the in vitro and in vivo response to leishmania amazonensis infection in susceptible (balb/c) and resistant (c3h/hepas) mice. pharmacologic or genetic deficiency of lts resulted in impaired leishmanicidal activity of peritoneal ma ... | 2006 | 16920959 |
| mimetic membrane system to carry multiple antigenic proteins from leishmania amazonensis. | liposomes have long been used as models for lipid membranes and for the reconstitution of a single or multiple proteins. also, liposomes have adjuvant activity in vaccines against several protozoan or bacterial organisms. thus, the main objective of the present study was to obtain a crude extract of detergent-solubilized proteins of leishmania amazonensis amastigotes and reconstitute them into liposomes. neutral and zwiterionic detergents were less efficient than an ionic detergent. in order to ... | 2006 | 16909340 |
| leishmania promastigotes activate pi3k/akt signalling to confer host cell resistance to apoptosis. | previous reports have shown that cells infected with promastigotes of some leishmania species are resistant to the induction of apoptosis. this would suggest that either parasites elaborate factors that block signalling from apoptosis inducers or that parasites engage endogenous host signalling pathways that block apoptosis. to investigate the latter scenario, we determined whether leishmania infection results in the activation of signalling pathways that have been shown to mediate resistance to ... | 2007 | 16889626 |
| leishmania (viannia) braziliensis is the prevalent species infecting patients with tegumentary leishmaniasis from mato grosso state, brazil. | the frequency of leishmania (viannia) braziliensis infection among patients of mato grosso, brazil was estimated by polymerase chain reaction-pcr, dna hybridization and by isoenzyme electrophoresis. analysis of dna polymorphism was carried out using random amplified polymorphic dna-pcr (rapdpcr) with five different primers. the patients were attended from may 1997 to february 1998 at the reference ambulatory for american tegumentary leishmaniasis at júlio müller university hospital of the federa ... | 2006 | 16846569 |
| novel dermaseptins from phyllomedusa hypochondrialis (amphibia). | six new antimicrobial peptides structurally related to the dermaseptin family have been isolated from the skin secretion of the amphibian phyllomedusa hypochondrialis. the primary structures of these molecules named as dshypo 01, 02, 03, 04, 06, and 07 were determined by de novo ms/ms experiments, edman degradation, and cdna sequencing. the fifth peptide was found to be precisely the same ds 01 from phyllomedusa oreades previously described by our group. the majority of the peptides purified fro ... | 2006 | 16844081 |
| antileishmanial activity of mdl 28170, a potent calpain inhibitor. | several calpain inhibitors are under development and some are useful agents against important human pathogens. we therefore investigated the effect of mdl 28170, a potent calpain inhibitor, on the growth of leishmania amazonensis. after 48 h of treatment, the inhibitor exhibited a dose-dependent antileishmanial activity, with a 50% lethal dose (ld(50)) of 23.3 microm. the inhibitor promoted cellular alterations, such as the parasites becoming short and round. a calpain-like protein migrating at ... | 2006 | 16842979 |
| electrospray ionization mass spectrometry analysis of polyisoprenoid alcohols via li+ cationization. | direct analysis of polyisoprenoids by electrospray ionization mass spectrometry (esi-ms) often produces poor results requiring off-line time and sample-consuming derivatization techniques. we describe a simple esi-ms approach for the direct analysis of polyisoprenoids using several dolichols and polyprenols with different chain sizes as proof-of-principle cases. lithium iodide is used to promote cationization by intense formation of [m+li]+ adducts. thus, detection of polyisoprenoids with mass d ... | 2006 | 16842733 |
| protection against cutaneous leishmaniasis by intranasal vaccination with lipophosphoglycan. | we previously showed the opposing effect of systemic and mucosal vaccination with whole leishmania amazonensis antigen (laag). here, the role played by lipophosphoglycan (lpg) as the key disease-promoting component of intramuscular (i.m.) laag and its usefulness as a defined intranasal vaccine was investigated in murine cutaneous leishmaniasis. balb/c mice were twice vaccinated by the i.m. route with 25mug of intact laag or with laag that was pretreated with anti-lpg 3a1-la monoclonal antibody, ... | 2007 | 16814903 |
| leishmania amazonensis: characterization of an ecto-phosphatase activity. | we have characterized a phosphatase activity present on the external surface of leishmania amazonensis, using intact living parasites. this enzyme hydrolyzes the substrate p-nitrophenylphosphate (p-npp) at the rate of 25.70+/-1.17 nmol pi x h(-1) x 10(-7)cells. the dependence on p-npp concentration shows a normal michaelis-menten kinetics for this ecto-phosphatase activity present a v(max) of 31.93+/-3.04 nmol pi x h(-1) x 10(-7)cells and apparent k(m) of 1.78+/-0.32 mm. inorganic phosphate inhi ... | 2006 | 16814776 |
| comparative two-dimensional gel electrophoresis maps for promastigotes of leishmania amazonensis and leishmania major. | the outcome of leishmania infections is determined by both the parasite species and the host genetic makeup. while much has been learned regarding immune responses to this parasite, our knowledge on parasite-derived factors is limited. the recent completion of the l. major and l. infantum genome sequence projects and concurrent advancement in proteomics technology would greatly accelerate the search for novel leishmania proteins. using a proteomics-based approach to study species-specific leishm ... | 2006 | 16767307 |
| leishmania tarentolae: purification and characterization of tubulin and its suitability for antileishmanial drug screening. | previously, tubulin has been purified from leishmania amazonensis and used to identify novel molecules with selective antimitotic activity. however, l. amazonensis is pathogenic and requires a relatively expensive medium for large-scale cultivation. herein, the purification and characterization of tubulin from the non-pathogenic leishmania tarentolae is reported, together with the sequence of alpha- and beta-tubulin from this organism. this protein was purified by sonication, diethylaminoethyl-s ... | 2006 | 16753146 |
| gp63-like molecules in phytomonas serpens: possible role in the insect interaction. | in this study, we demonstrated that metallopeptidase inhibitors (edta, egta, and 1,10-phenanthroline) were able to arrest phytomonas serpens growth in distinct patterns. this parasite released exclusively metallopeptidases to the extracellular environment, whereas in cellular extracts only cysteine peptidases were detected. in addition, an extracellular polypeptide of 60 kda reacted in western blotting probed with polyclonal antibody raised against gp63 of leishmania amazonensis. in the cellular ... | 2006 | 16732452 |
| down-regulation of gp63 level in leishmania amazonensis promastigotes reduces their infectivity in balb/c mice. | episomal expression of the major surface glycoprotein (gp63) sense and antisense mrnas in leishmania amazonensis was found previously to modulate the expression of this molecule as well as its infection of macrophages in vitro. here, we evaluated the in vivo infectivity of these transfectants in balb/c mice. antisense downregulation of gp63 renders this parasite sensitive to complement-mediated lysis and less infective to mice, as indicated by a delay in lesion development and a significant redu ... | 2006 | 16698300 |
| effect of imidocarb and levamisole on the experimental infection of balb/c mice by leishmania (leishmania) amazonensis. | the adverse effects from using currently available drugs for the treatment of leishmaniasis have motivated the search for new therapeutical agents. the aim of this work was to evaluate the effect of imidocarb and levamisole on the treatment of balb/c mice experimentally infected by leishmania (leishmania) amazonensis. balb/c mice were infected with 10(6) promastigotes of l. (l.) amazonensis (ifla/br/67/ph8) and, starting on day 51, mice were treated subcutaneously with imidocarb (imd, 34 mg/kg), ... | 2006 | 16647821 |
| hyperbaric oxygen therapy reduces the size of leishmania amazonensis-induced soft tissue lesions in mice. | in this study we determined whether exposing mice to hyperbaric oxygen (hbo) would alter various disease parameters of a susceptible mouse strain infected with leishmania amazonensis. balb/c mice exposed to hbo (100% o2 at a pressure of 2.5 ata, 1h before parasite inoculation and subsequently for 20 days) showed significant delay in lesion development and reduction in lesion parasite burdens compared with hbo-unexposed mice. circulating levels of interferon gamma (ifn-gamma) and tumor necrosis f ... | 2006 | 16638602 |
| activity of the essential oil from chenopodium ambrosioides grown in cuba against leishmania amazonensis. | current therapy against leishmaniasis is unsatisfactory. efficacious and safe new drugs are needed. in this study, we show the leishmanicidal effect of an essential oil from chenopodium ambrosioides against leishmania amazonensis. | 2006 | 16636536 |
| efficacy of vaccination with a combination of leishmania amastigote antigens and the lipid a-analogue ono-4007 for immunoprophylaxis and immunotherapy against leishmania amazonensis infection in a murine model of new world cutaneous leishmaniasis. | activation of innate immunity using adjuvants that activate toll-like receptor 4 pathways have great potential for improving the protection induced by parasite vaccines. we investigated protective and therapeutic effects of a vaccine against leishmaniasis containing a combination of an adjuvant synthetic lipid a-analogue, ono-4007 and leishmania amazonensis antigens. ono-4007 was co-injected with soluble and membrane-enriched l. amazonensis-amastigote antigens into balb/c mice that had either al ... | 2006 | 16621179 |
| use of enzyme-linked immunosorbent assay for detection of natural leishmania infections in phlebotomine sand flies from southeastern turkey. | in total, 320 phelebotomine sand flies from alibozlu (osmaniye), kizyusuflu (osmaniye), and sanliurfa in southeastern turkey were tested for the detection and identification of leishmania in vector sand flies by enzyme-linked immunosorbent assay with species-specific monoclonal antibodies. we used monoclonal antibodies that recognize both leishmania tropica and leishmania major, and a monoclonal antibody specific only to l. tropica. phosphate-buffered saline and monoclonal antibody m2 recognizin ... | 2006 | 16619606 |
| leishmania amazonensis: biological and biochemical characterization of ecto-nucleoside triphosphate diphosphohydrolase activities. | the presence of leishmania amazonensis ecto-nucleoside triphosphate triphosphohydrolase activities was demonstrated using antibodies against different ntpdase members by western blotting, flow cytometry, and immunoelectron microscopy analysis. living promastigote cells sequentially hydrolyzed the atp molecule generating adp, amp, and adenosine, indicating that this surface enzyme may play a role in the salvage of purines from the extracellular medium. the l. amazonensis ecto-ntpdase activities w ... | 2006 | 16603157 |
| nitric oxide biosynthesis by leishmania amazonensis promastigotes containing a high percentage of metacyclic forms. | due to the diversity of its physiological and pathophysiological functions and general ubiquity, the study of nitric oxide (no) has become of great interest. in this work, it was demonstrated that leishmania amazonensis promastigotes produces no, a free radical synthesized from l: -arginine by nitric oxide synthase (nos). a soluble nos was purified from l. amazonensis promastigotes by affinity chromatography (2', 5'-adp-agarose) and on sds-page the enzyme migrates as a single protein band of 116 ... | 2006 | 16575586 |
| montenegro's skin reactions and antibodies against different leishmania species in dogs from a visceral leishmaniosis endemic area. | in this study, humoral (circulating anti-leishmania antibodies) and cellular (montenegro's skin test) immune responses of dogs from an endemic area of visceral leishmaniosis were tested using leishmania chagasi, leishmania amazonensis and leishmania braziliensis antigens. the antibody response was tested in three animal groups, selected according to their anti-l. chagasi antibody activity, as measured by elisa in the serum: 19 negative (o.d. below 0.30), seven with undefined (o.d. between 0.40 a ... | 2006 | 16567046 |
| leishmania amazonensis: metabolic adaptations induced by resistance to an abc transporter blocker. | we compared growth rate, cell glucose turnover and expression of atp-binding-cassette (abc) transporters in leishmania amazonensis (ltb0016; ltb) versus ltb(160) selected for resistance against the abc transporter blocker glibenclamide. additionally, we evaluated the influence of drug-resistance on leishmania sensitivity against 2-mercaptoacetate and 2-deoxyglucose. our data demonstrate that (1) ltb(160) and ltb constitutively express abc transporters for neutral substrates, (2) glibenclamide re ... | 2006 | 16545807 |
| role of interleukin-4 and prostaglandin e2 in leishmania amazonensis infection of balb/c mice. | the role of cytokines in leishmania amazonensis experimental infection has not been as well studied as in leishmania major infection model. here we investigated the role of interleukin (il)-4 and pge(2) in l. amazonensis infection of susceptible balb/c mice. il-4 deficient (-/-) or wild-type (+/+) balb/c mice were infected with different inocula of l. amazonensis. two weeks after infection with 5x10(6) promastigotes/footpad, the production of interferon (ifn)-gamma upon l. amazonensis antigen st ... | 2006 | 16531090 |
| leishmanicidal activity of primary s-nitrosothiols against leishmania major and leishmania amazonensis: implications for the treatment of cutaneous leishmaniasis. | nitric oxide (no) is considered a key molecule in the defense against intracellular pathogens, particularly leishmania. the expression of inducible nitric oxide synthase and consequent production of no by infected macrophages has been shown to correlate with leishmaniasis resistance in the murine model as well as in human patients. nitric oxide donors have been used successfully in the treatment of cutaneous leishmaniasis in humans, although their mechanisms of action are not fully understood. i ... | 2006 | 16527502 |
| role of residual sb(iii) in meglumine antimoniate cytotoxicity and mrp1-mediated resistance. | despite the clinical use of pentavalent antimonials for more than half a century, their metabolism in mammals and mechanisms of action and toxicity remain poorly understood. it has been proposed that the more active and toxic trivalent antimony form sb(iii) plays a critical role in their antileishmanial activity and toxicity. the aim of this work was to investigate the role of residual sb(iii) both in the antileishmanial/antitumoral activities of the pentavalent meglumine antimoniate and in the ... | 2006 | 16524568 |
| inflammatory lesion and parasite load are inversely associated in leishmania amazonensis infected mice genetically selected according to oral tolerance susceptibility. | two strains of mice selected according to extreme phenotypes of susceptibility and resistance to oral tolerance (ts and tr mice, respectively) were infected with 1 x 10(7) leishmania amazonensis promastigotes and studied comparatively. ts mice developed a minor pathology while permitting parasite growth with the presence of increased il-4, il-10 and ifn-gamma, and lower no and il-2 levels and delayed-type hypersensitivity (dth). in contrast, in tr mice, footpad swelling was increased but parasit ... | 2006 | 16516520 |
| leishmania amazonensis: participation of regulatory t and b cells in the in vitro priming (piv) of cba/j spleen cells susceptible response. | cba/j mice are resistant to leishmania major and susceptible to leishmania amazonensis. early events determine infection outcome. until now, piv (in vitro priming) immune response to l. amazonensis has not been assessed. herein, we have shown that compared to l. major, l. amazonensis induced higher parasite burden associated to similar il-4, ifn-gamma, and tnf-alpha mrna expressions and ifn-gamma and il-10 levels. although similar amounts of il-10 were detected, the frequency of intracellular il ... | 2006 | 16516200 |
| nitric oxide synthase (nos) characterization in leishmania amazonensis axenic amastigotes. | although leishmania virulence may be modulated by environmental and genetic factors of their mammalian hosts and sand fly vectors, molecular determinants of leishmania sp. are the key elements. this work evidences that leishmania amazonensis axenic amastigotes produce comparatively more no than infective promastigotes. | 2006 | 16513480 |
| [occurrence of american tegumentary leishmaniasis in the mato grosso do sul state associated to the infection for leishmania (leishmania) amazonensis]. | nine cases of american tegumentary leishmaniasis were reported at a training military unit located in bela vista city, state of mato grosso do sul. parasites obtained from lesions of six patients were isolated in culture media followed by identification, through isoenzymes analysis, as being leishmania amazonensis. this is the first evidence of the presence of the parasite in mato grosso do sul. | 2006 | 16501765 |
| antigen-responsive cd4+ t cells from c3h mice chronically infected with leishmania amazonensis are impaired in the transition to an effector phenotype. | c3heb/fej mice challenged with leishmania major develop a polarized th1 response and subsequently heal, whereas leishmania amazonensis challenge leads to chronic lesions with high parasite loads at 10 weeks postinfection. in this study, a comparison of draining lymph node cells from l. amazonensis- and l. major-infected mice at 10 weeks postinfection showed equivalent percentages of effector/memory phenotype cd44hi cd4+ t cells producing interleukin-2 (il-2) and proliferating after antigen stimu ... | 2006 | 16495525 |
| the occurrence of free d-alanine and an alanine racemase activity in leishmania amazonensis. | free d-amino acids are implicated in several biological functions. this study examined the presence of d-alanine in leishmania amazonensis. measuring chiral amino acid content by high-performance liquid chromatography we detected a significant amount of free d-alanine in promastigotes of these parasites. d-alanine accounts for 8.9% of total free alanine and is found primarily in the soluble fraction. specific racemization of l-alanine to d-alanine was detected in cell lysates and this enzyme act ... | 2006 | 16487314 |
| vaccine-induced protection against leishmania amazonensis is obtained in the absence of il-12/23p40. | protozoa of the genus leishmania are intracellular parasites of macrophages and may cause diverse clinical forms of leishmaniasis, including cutaneous, diffuse cutaneous, mucocutaneous and visceral leishmaniasis. infection with l. major in mice indicates that a protective immune response is achieved when th1 cells are developed. thus, adoptive or vaccine-induced protection against leishmaniasis is largely dependent on cell-mediated immunity and ifn-gamma production. induction of a th1 response i ... | 2006 | 16466810 |
| potential of km+ lectin in immunization against leishmania amazonensis infection. | in the present study we evaluated canavalia brasiliensis (conbr), pisum arvense (paa) and artocarpus integrifolia (km+) lectins as immunostimulatory molecules in vaccination against leishmania amazonensis infection. although they induced ifn-gamma production, the combination of the lectins with sla antigen did not lead to lesion reduction. however, parasite load was largely reduced in mice immunized with km+ lectin and sla. km+ induced a smaller inflammatory reaction in the air pouch model and w ... | 2006 | 16455170 |
| the putative telomerase reverse transcriptase component of leishmania amazonensis: gene cloning and characterization. | the leishmania amazonensis telomerase gene was cloned by a polymerase chain reaction-based strategy using primers designed from a leishmania major sequence that shared similarities with conserved telomerase motifs. the genes from three other species were cloned for comparative purposes. a clustalw multiple-sequence alignment demonstrated that the leishmania telomerases show greater homology with each other than with the proteins of other kinetoplastids and eukaryotes. characterization experiment ... | 2006 | 16416120 |
| in vitro responses of human peripheral blood mononuclear cells to whole-cell, particulate and soluble extracts of leishmania promastigotes. | whole-cell and soluble extracts of leishmania promastigotes have both been used as skin test antigens and have also been tested as vaccine candidates. however, the differences in antigenicity between soluble and particulate leishmania fractions are not known. we evaluated in vitro responses of pbmc from 30 american tegumentary leishmaniasis (atl) patients and seven noninfected donors to different antigen preparations from leishmania promastigotes, namely leishmania amazonensis and l. braziliensi ... | 2006 | 16412059 |
| synthesis of chalcone analogues with increased antileishmanial activity. | eighteen analogues of an active natural chalcone were synthesized using xanthoxyline and some derivatives, and these analogues were tested for selective activity against both promastigotes and intracellular amastigotes of leishmania amazonensis in vitro. three analogues (10, 12, and 19) containing nitro, fluorine or bromine groups, respectively, displayed increased selective activity against the parasites as compared with the natural chalcone. the nitrosylated chalcone 10 was also tested intrale ... | 2006 | 16386424 |
| phagocytosis, endosomal/lysosomal system and other cellularaspects of macrophage activation by canova medication. | canova is a homeopathic medication with immunomodulatory properties, recommended for diseases where the immune system is depressed. our research aims to study the activation of mice peritoneal macrophages when submitted to in vivo and in vitro canova treatment. morphological parameters and acid phosphatase activity were analyzed using light and transmission electron microscopy. differential interference contrast microscopy, including serial time acquisition in living cells, was also performed. t ... | 2006 | 16364649 |
| antileishmanial activity of eugenol-rich essential oil from ocimum gratissimum. | leishmaniasis is a group of diseases with a large spectrum of clinical manifestations caused by protozoans of the genus leishmania. here we demonstrate the leishmanicidal activity of the essential oil of ocimum gratissimum as well as its main constituent, eugenol. the eugenol-rich essential oil of o. gratissimum progressively inhibited leishmania amazonensis growth at concentrations ranging from 100 to 1000 microg/ml. the ic50 (sub-inhibitory concentration) of the essential oil for promastigotes ... | 2006 | 16343984 |
| leishmania amazonensis: chemotaxic and osmotaxic responses in promastigotes and their probable role in development in the phlebotomine gut. | taxic responses may play a role in development of leishmania in their phlebotomine sand fly vectors. they are possibly responsible for movement of the parasites towards the anterior regions of the gut, from where they would be transmitted to the vertebrate host. a methodology capable to distinguish chemotaxic from osmotaxic responses was described and used to characterise taxic responses in leishmania promastigotes. these were able to respond to chemotaxic as well as to osmotaxic stimuli. like b ... | 2006 | 16313904 |
| isolation of a new l-amino acid oxidase from crotalus durissus cascavella venom. | a novel l-amino acid oxidase (lao) (casca lao) from crotalus durissus cascavella venom was purified to a high degree of molecular homogeneity using a combination of molecular exclusion and ion-exchange chromatography system. the purified monomer of lao presented a molecular mass of 68 kda and pi estimated in 5.43, which were determined by two-dimensional electrophoresis. the 71st n-terminal amino acid sequence of the lao from crotalus durissus cascavella presented a high amino acid sequence simi ... | 2006 | 16307769 |
| efficacy of orally administered 2-substituted quinolines in experimental murine cutaneous and visceral leishmaniases. | we report in this study the in vivo efficacy of nine 2-substituted quinolines on the leishmania amazonensis cutaneous infection murine model and on the leishmania infantum and leishmania donovani visceral infection murine models. in the case of the l. amazonensis model, quinolines were administered orally at 25 mg/kg twice daily for 15 days. quinolines 1, 2, 3, and 7 reduced by 80 to 90% the parasite burdens in the lesion, whereas n-methylglucamine antimoniate (glucantime), administered by subcu ... | 2005 | 16304157 |
| a soluble pyrophosphatase, a key enzyme for polyphosphate metabolism in leishmania. | we report the functional characterization in leishmania amazonensis of a soluble pyrophosphatase (lavsp1) that localizes in acidocalcisomes, a vesicular acidic compartment. lavsp1 is preferentially expressed in metacyclic forms. experiments with dominant negative mutants show the requirement of lavsp1 functional expression for metacyclogenesis and virulence in mice. depending on the ph and the cofactors mg2+ or zn2+, both present in acidocalcisomes, lavsp1 hydrolyzes either inorganic pyrophospha ... | 2006 | 16291745 |
| interleukin-2-activated natural killer cells may have a direct role in the control of leishmania (leishmania) amazonensis promastigote and macrophage infection. | to study the role of natural killer (nk) cells in leishmania infection, peritoneal macrophages from balb/c mice were infected with leishmania (leishmania) amazonensis promastigotes and incubated with interleukin-2 (il-2)-activated nk (a-nk) cells at different ratios of a-nk cells to infected macrophages (5:1, 1:1, 0.2:1). the a-nk cells were added either together with the parasites (0-h group) or 24 h later (24-h group). morphological studies of the cultures revealed predominance of parasitic de ... | 2005 | 16253120 |
| photodynamic sensitization of leishmania amazonensis in both extracellular and intracellular stages with aluminum phthalocyanine chloride for photolysis in vitro. | leishmania amazonensis, a causative agent of cutaneous leishmaniasis, is susceptible in vitro to light-mediated cytolysis in the presence of or after pretreatment with the photosensitizer aluminum phthalocyanine chloride. cytolysis of both promastigotes and axenic amastigotes required less photosensitizer (e.g., one microg.ml(-1)) and a lower light dose (e.g., 1.5 j.cm(-2)) than did the mammalian cells examined for comparison. exposure of leishmania cells to the photosensitizer alone had little ... | 2005 | 16251285 |
| atypical american visceral leishmaniasis caused by disseminated leishmania amazonensis infection presenting with hepatitis and adenopathy. | leishmania amazonensis is widely recognised as a cause of cutaneous leishmaniasis in latin america, but it can also disseminate to produce atypical visceral leishmaniasis with hepatitis and lymphadenopathy. the patient, an 8-year-old brazilian boy, presented with a febrile illness and hepatosplenomegaly, elevated liver enzymes and generalised adenopathy. serological tests using antigens of l. chagasi, the typical cause of visceral leishmaniasis in latin america, were inconclusive. leishmania ama ... | 2006 | 16198385 |
| antiproliferative and ultrastructural effects of bpq-oh, a specific inhibitor of squalene synthase, on leishmania amazonensis. | parasites of the leishmania genus require for the growth and viability the de novo synthesis of specific sterols as such as episterol and 5-dehydroepisterol because cholesterol, which is abundant in their mammalian hosts, does not fulfill the parasite sterol requirements. squalene synthase catalyzes the first committed step in the sterol biosynthesis and has been studied as a possible target for the treatment of high cholesterol levels in humans. in this work we investigated the antiproliferativ ... | 2005 | 16198340 |
| further observations on clinical, histopathological, and immunological features of borderline disseminated cutaneous leishmaniasis caused by leishmania (leishmania) amazonensis. | leishmania (leishmania) amazonensis has for some time been considered as the causative agent of two distinct forms of american cutaneous leishmaniasis (acl): localized cutaneous leishmaniasis (lcl), and anergic diffuse cutaneous leishmaniasis (adcl). recently, a new intermediate form of disease, borderline disseminated cutaneous leishmaniasis (bdcl), was introduced into the clinical spectrum of acl caused by this parasite, and in this paper we record the clinical, histopathological, and immunolo ... | 2005 | 16184231 |
| new clerodane diterpenoids from laetia procera (poepp.) eichler (flacourtiaceae), with antiplasmodial and antileishmanial activities. | extracts of laetia procera (flacourtiaceae) displayed significant in vitro activity against plasmodium falciparum. p. falciparum bioassay guided fractionation of a trunk bark extract of this plant led to the isolation of six clerodane diterpenoids (1-6) and a butanolide (7). five of these compounds are new and called laetiaprocerine a-d (3-6) and laetianolide a (7). their structures were established on the basis of 1d and 2d nmr experiments. absolute configurations of 1 and 2 were determined by ... | 2005 | 16168652 |
| genomic organization of telomeric and subtelomeric sequences of leishmania (leishmania) amazonensis. | telomeres are dna-protein complexes that protect linear chromosomes from degradation and fusions. telomeric dna is repetitive and g-rich, and protrudes towards the end of the chromosomes as 3'g-overhangs. in leishmania spp., sequences adjacent to telomeres comprise the leishmania conserved telomere associated sequences (lctas) that are around 100 bp long and contain two conserved sequence elements (csb1 and csb2), in addition to non-conserved sequences. the aim of this work was to study the geno ... | 2005 | 16126212 |
| subcellular localization of an intracellular serine protease of 68 kda in leishmania (leishmania) amazonensis promastigotes. | here we report the subcellular localization of an intracellular serine protease of 68 kda in axenic promastigotes of leishmania (leishmania) amazonensis, using subcellular fractionation, enzymatic assays, immunoblotting, and immunocytochemistry. all fractions were evaluated by transmission electron microscopy and the serine protease activity was measured during the cell fractionation procedure using alpha-n-r-tosyl-l-arginine methyl ester (l-tame) as substrate, phenylmethylsulphone fluoride (pms ... | 2005 | 16113885 |
| leishmania (viannia) braziliensis growth in vitro culture relies more on folic acid availability than leihsmania (leishmania) amazonensis. | we compared the in vitro growth of promastigotes from two leishmania species in tc-100 and schneider media. leishmania (leishmania) amazonensis replication rates were similar in both tissue culture media and reached maximum rates by 48 h. in contrast leishmania (viannia) braziliensis growth was significantly greater in tc-100 but maximum rates were achieved by 96 h. folic acid appears to be the limiting factor and supplementation of schneider media with this nutrient improved l. (v.) braziliensi ... | 2005 | 16113874 |
| axenic promastigote forms of leishmania (viannia) lainsoni as an alternative source for leishmania antigen production. | the present study demonstrates that axenic cultures of leishmania (viannia) lainsoni produce larger cell masses in nnn-lit medium, as well as higher amounts of total proteins in cell extracts, than leishmania (leishmania) amazonensis. antigenicity of l. (v.) lainsoni whole promastigotes is similar to that of l. (l.) amazonensis, as demonstrated by an indirect immunofluorescence diagnostic test using sera from human patients and dogs infected with visceral leishmaniasis. infectivity of the l. (v. ... | 2005 | 16108545 |
| differences in morphology of phagosomes and kinetics of acidification and degradation in phagosomes between the pathogenic entamoeba histolytica and the non-pathogenic entamoeba dispar. | phagocytosis plays an important role in the pathogenicity of the intestinal protozoan parasite entamoeba histolytica. we compared the morphology of phagosomes and the kinetics of phagosome maturation using conventional light and electron microscopy and live imaging with video microscopy between the virulent e. histolytica and the closely-related, but non-virulent e. dispar species. electron micrographs showed that axenically cultivated trophozoites of the two entamoeba species revealed morpholog ... | 2005 | 16106449 |
| plant active components - a resource for antiparasitic agents? | plant essential oils (and/or active components) can be used as alternatives or adjuncts to current antiparasitic therapies. garlic oil has broad-spectrum activity against trypanosoma, plasmodium, giardia and leishmania, and cochlospermum planchonii and croton cajucara oils specifically inhibit plasmodium falciparum and leishmania amazonensis, respectively. some plant oils have immunomodulatory effects that could modify host-parasite immunobiology, and the lipid solubility of plant oils might off ... | 2005 | 16099722 |
| immunomodulatory effect of canova medication on experimental leishmania amazonensis infection. | this study investigates the action of canova medication (cm) on experimental infection by leishmania (leishmania) amazonensis, utilizing in vitro and in vivo assays. for the in vitro tests, balb/c mouse peritoneal macrophages (5x10(5) cells in 500 microl of culture medium, supplemented with 10% fetal calf serum, penicillin (100 u/ml) and streptomycin (0.1 mg/ml) (were distributed in 24-well plates and cm was added at concentrations of 20 or 40%. twenty-four hours later, the macrophages were infe ... | 2004 | 16038768 |
| characterization of an extracellular serine protease of leishmania (leishmania) amazonensis. | a serine protease was purified 942-fold from culture supernatant of l. amazonensis promastigotes using (nh4)2so4 precipitation followed by affinity chromatography on aprotinin-agarose and continuous elution electrophoresis by prep cell, yielding a total recovery of 61%. the molecular mass of the active enzyme estimated by sds-page under conditions of reduction was 56 kda and 115 kda under conditions of non-reduction, suggesting that the protease is a dimeric protein. additionally, it was found t ... | 2005 | 16038400 |
| tgf-beta-associated enhanced susceptibility to leishmaniasis following intramuscular vaccination of mice with leishmania amazonensis antigens. | leishmania amazonensis and leishmania braziliensis are the main causal agents of anergic diffuse cutaneous leishmaniasis and hyperergic mucosal leishmaniasis in man, respectively. in this work we demonstrate that intramuscular vaccination of balb/c mice with whole antigens of l. amazonensis (laag) but not l. braziliensis (lbag) results in increased susceptibility to cutaneous leishmaniasis. laag vaccination resulted in an increased capacity of the draining lymph nodes to produce il-10 and tgf-be ... | 2005 | 16027022 |
| evaluation of enzyme-linked immunosorbent assay using crude leishmania and recombinant antigens as a diagnostic marker for canine visceral leishmaniasis. | the performances of elisa assays with different antigen preparations, such as leishmania amazonensis or l. chagasi lysates and the recombinant antigens rk-39 and rk-26, were compared using sera or eluates from dried blood collected on filter paper to detect anti-leishmania antibodies in dogs from a visceral leishmaniasis-endemic area in brazil. of 115 ifat-reactive dogs at 1:40 titre, 106 (92.2%) were positive in parasitological exams (skin and/or spleen). these animals were compared to healthy ... | 2005 | 16021309 |
| american tegumentary leishmaniasis: a quantitative analysis of langerhans cells presents important differences between l. (l.) amazonensis and viannia subgenus. | a quantitative study was conducted on the density of langerhans cells (lcs) cd1a+ in specimens obtained from patients with american tegumentary leishmaniasis (atl) lesions without previous treatment, as well as from control healthy individuals. lc density was significantly higher among infected patients when compared to controls and also higher in longer term ones. regarding parasite quantities, these were proportionally inverse and diminished in chronic patients. localized cutaneous leishmanias ... | 2005 | 15935321 |
| distinct overexpression of cytosolic and mitochondrial tryparedoxin peroxidases results in preferential detoxification of different oxidants in arsenite-resistant leishmania amazonensis with and without dna amplification. | a cytosolic (ctxnpx) and a mitochondrial (mtxnpx) tryparedoxin peroxidase genes, cloned from wildtype leishmania amazonensis clone 2-23 are homologous in nucleic acid and amino acid sequences to the respective genes described for l. infantum and l. chagasi. surprisingly, as shown in the results of transcription assays, protein determination and fluorescent antibody detection in situ, ctxnpx is distinctly overexpressed in the cytoplasm of arsenite-resistant a variant with dna amplification, where ... | 2005 | 15907561 |
| cd4+cd25+ regulatory t cells restrain pathogenic responses during leishmania amazonensis infection. | although activation of cd4(+) t cells mediates pathogenesis in leishmania amazonensis (la)-infected mice, these susceptible mice do not develop a polarized th2 response, suggesting a unique mechanism of disease susceptibility. to understand how th cell activities are regulated, we examined the frequency and phenotypes of regulatory t (treg) cells. at 1-3 wk of infection, relatively high percentages of cd4(+)cd25(+)cd86(+) t cells, as well as high levels of foxp3, tgf-beta1, and il-10ri transcrip ... | 2005 | 15905558 |
| in vitro activities of thiadiazine derivatives against leishmania amazonensis. | ten thiadiazine derivatives were tested in vitro for antiparasitic effects against both extracellular promastigotes and intracellular amastigotes of leishmania amazonensis. the results showed that the evaluated compounds exhibited a strong antiproliferative activity on all developmental stages of the parasite. the minimal inhibitory concentration and the 50 % effective concentration values against the promastigote were 2.1-5.1 microg/ml and 0.6-1.8 microg/ml, respectively. the tested compounds c ... | 2005 | 15901047 |
| amidine derivatives and leishmania amazonensis: an evaluation of the effect of nitric oxide (no) production on the parasite-macrophage interaction. | previous work has demonstrated that n-n'-diphenyl-r-benzamidine was highly effective against leishmania amazonensis promastigotes/axenic amastigotes and trypanosoma evansi trypomastigotes and the compound with a methoxy substituent, was the most effective derivative in the parasite-macrophage interaction. comparative analysis of the nitric oxide (no) released from the culture infection's supernatant showed the amidine to be less effective than pentamidine isethionate as a reference drug. additio ... | 2005 | 15895679 |
| failure of a killed leishmania amazonensis vaccine against american cutaneous leishmaniasis in colombia. | we report the results of a double-blind, randomized, placebo-controlled clinical trial of a killed whole-cell leishmania amazonensis candidate vaccine against american cutaneous leishmaniasis (cl) in colombia. the trial subjects were 2597 healthy volunteers with negative leishmanin skin test (lst) selected from rural colombian soldiers who were going to patrol endemic areas. they were randomized to receive either three doses of vaccine (n=1295) or placebo (n=1302) given at 20-day intervals. an a ... | 2005 | 15893351 |
| colorimetric assay for screening compounds against leishmania amastigotes grown in macrophages. | an estimated 12 million persons throughout the world suffer from the protozoan disease leishmaniasis. current treatments have liabilities including poor activity against some forms of leishmaniasis, toxicity, or the need for parenteral administration. higher throughput methods to screen chemical compounds are needed to facilitate the search for new antileishmania drugs. in the mammalian host, leishmania parasites exist as amastigotes that replicate within macrophages. therefore, an in vitro scre ... | 2005 | 15891135 |
| effect of a juvenile hormone analogue on leishmania amazonensis and leishmania braziliensis. | 2005 | 15888299 | |
| the 3a1-la monoclonal antibody reveals key features of leishmania (l) amazonensis metacyclic promastigotes and inhibits procyclics attachment to the sand fly midgut. | in this work, we characterise metacyclic promastigotes of leishmania amazonensis, the causative agent of cutaneous and diffuse cutaneous leishmaniasis in the new world. to purify metacyclics from stationary culture by negative selection, we used the monoclonal antibody 3a1-la produced against procyclic promastigotes. the purified forms named 3a1-la(-) promastigotes, present key metacyclic characteristics: slender cell body and long flagella, ultrastructural features, resistance to complement lys ... | 2005 | 15885694 |