| dynamics of polymorphism of acidocalcisomes in leishmania parasites. | growth of leishmania mexicana amazonensis promastigotes in different culture media resulted in structurally and chemically different acidocalcisomes. when grown in sdm-79 medium, the promastigotes showed large spherical acidocalcisomes of up to 1.2 microm diameter distributed throughout the cell. x-ray microanalysis and elemental mapping of the organelles showed large amounts of oxygen, phosphorus, sodium, potassium, magnesium, calcium, and zinc. immunofluorescence microscopy using antisera rais ... | 2004 | 15138840 |
| a cardiac myosin-specific autoimmune response is induced by immunization with trypanosoma cruzi proteins. | trypanosoma cruzi is the protozoan parasite that causes chagas' heart disease, a potentially fatal cardiomyopathy prevalent in central and south america. infection with t. cruzi induces cardiac myosin autoimmunity in susceptible humans and mice, and this autoimmunity has been suggested to contribute to cardiac inflammation. to address how t. cruzi induces cardiac myosin autoimmunity, we investigated whether immunity to t. cruzi antigens could induce cardiac myosin-specific autoimmunity in the ab ... | 2004 | 15155647 |
| down-regulation of gp63 in leishmania amazonensis reduces its early development in lutzomyia longipalpis. | the zinc protease (gp63) of promastigotes was found to play a role in the sand fly part of the leishmania life cycle. lutzomyia longipalpis females were fed with promastigotes (10(6) per ml) of a leishmania amazonensis clone whose gp63 was up- and down-regulated by directional cloning into p6.5 for sense- and anti-sense transcription. early development was found to differ significantly between the sense- and anti-sense transfectants 2 days post-feeding. the sense transfectants overexpressing gp6 ... | 2004 | 15158771 |
| subcellular localization of an extracellular serine protease in leishmania (leishmania) amazonensis. | extracellular proteolytic activity was detected in a leishmania ( l.) amazonensis culture supernatant and a 56-kda protein was purified using (nh4)2so4 precipitation followed by affinity chromatography on aprotinin-agarose. a rabbit serum obtained against the 56-kda extracellular serine protease was used in order to analyze its location in l. ( l.) amazonensis parasites. immunocytochemistry studies revealed that the enzyme is mainly found in the flagellar pocket and cytoplasmic vesicles of proma ... | 2004 | 15185145 |
| trypanothione reductase activity is prominent in metacyclic promastigotes and axenic amastigotes of leishmania amazonesis. evaluation of its potential as a therapeutic target. | the activity of trypanothione reductase in leishmania amazonensis was evaluated and it was demonstrated that tr is expressed in the soluble fractions of infective promastigotes and amastigotes, while non-infective promastigotes expressed the enzyme at basal levels. this data allows an association of enzyme activity and the infective capacity of the parasite. we have also previously demonstrated that amidine compounds (n, n'-diphenyl-4-methoxy-benzamidine and pentamidine) were active against this ... | 2004 | 15202494 |
| development of leishmania (viannia) braziliensis and leishmania (leishmania) amazonensis in the sand fly lutzomyia migonei (diptera: psychodidae). | development of leishmania braziliensis (vianna) and leishmania amazonensis (lainson and shaw) in the sand fly lutzomyia migonei (frança) was compared by studying the parasite microhabitats in the alimentary tract, the sequence of parasite morphological changes leading to the metacyclogenesis process, and the parasite transmission to the vertebrate susceptible host. although the infections by the 2 leishmania species were initiated with the same number of amastigotes, le. amazonensis developed a ... | 2000 | 15218917 |
| identification of three proteins that associate in vitro with the leishmania (leishmania) amazonensis g-rich telomeric strand. | the chromosomal ends of leishmania (leishmania) amazonensis contain conserved 5'-ttaggg-3' telomeric repeats. protein complexes that associate in vitro with these dna sequences, leishmania amazonensis g-strand telomeric protein (lagt1-3), were identified and characterized by electrophoretic mobility shift assays and uv cross-linking using protein fractions purified from s100 and nuclear extracts. the three complexes did not form (a) with double-stranded dna and the c-rich telomeric strand, (b) i ... | 2004 | 15233802 |
| destiny and intracellular survival of leishmania amazonensis in control and dexamethasone-treated glial cultures: protozoa-specific glycoconjugate tagging and tunel staining. | leishmania amazonensis, an obligatory intracellular parasite, survives internalization by macrophages, but no information is available on the involvement of microglia. we have investigated microglia-protozoa interactions in mixed glial cultures infected with promastigote forms of l. amazonensis after lipopolysaccharide (lps) or dexamethasone (dm) treatment. after 2 hr of exposure to parasites in control cultures, there was a small number of infected microglia (1%). preincubation with lps or dm l ... | 2004 | 15258180 |
| effect of hypoxia on macrophage infection by leishmania amazonensis. | in the present study, we compared the effect of 5% oxygen tension (hypoxia) with a normal tension of 21% oxygen (normoxia) on macrophage infection by the protozoan parasite leishmania amazonensis. macrophages from different sources (human cell line u937, murine cell line j774, and murine peritoneal macrophages) exposed to hypoxia showed a reduction of the percentage of infected cells and the number of intracellular parasites per cell. observations on the kinetics of infection indicated that hypo ... | 2004 | 15270094 |
| cd4+ th1 cells induced by dendritic cell-based immunotherapy in mice chronically infected with leishmania amazonensis do not promote healing. | the susceptibility of mice to leishmania amazonensis infection is thought to result from an inability to develop a th1 response. our data show that the low levels of gamma interferon (ifn-gamma) produced by the draining lymph node (dln) cells of chronically infected mice could be enhanced in vitro and in vivo with l. amazonensis antigen-pulsed bone marrow-derived dendritic cells (bm-dc) and the th1-promoting cytokine interleukin-12 (il-12). given intralesionally to chronically infected mice, thi ... | 2004 | 15271903 |
| intranasal vaccination against cutaneous leishmaniasis with a particulated leishmanial antigen or dna encoding lack. | we have previously demonstrated that oral delivery of a disease-promoting particulated antigen of leishmania amazonensis (laag) partially protects mice against cutaneous leishmaniasis. in the present work, we sought to optimize a mucosal vaccine by using the intranasal route for delivery of different antigen preparations, including (i) laag, (ii) soluble recombinant p36/lack leishmanial antigen (lack), and (iii) plasmid dna encoding lack (lack dna). balb/c mice that received two intranasal doses ... | 2004 | 15271911 |
| novel azasterols as potential agents for treatment of leishmaniasis and trypanosomiasis. | this paper describes the design and evaluation of novel azasterols as potential compounds for the treatment of leishmaniasis and other diseases caused by trypanosomatid parasites. azasterols are a known class of (s)-adenosyl-l-methionine: delta24-sterol methyltransferase(24-smt) inhibitors in fungi, plants, and some parasitic protozoa. the compounds prepared showed activity at micromolar and nanomolar concentrations when tested against leishmania spp. and trypanosoma spp. the enzymatic and stero ... | 2004 | 15273104 |
| effect of thiadiazine derivatives on intracellular amastigotes of leishmania amazonensis. | current therapy for leishmaniasis is not satisfactory. we describe the in vitro antiproliferative effects of new thiadiazine derivatives against leishmania amazonensis. the compounds were found to be active against the amastigote form of the parasite, inhibiting parasite growing, from 10 to 89%, at a concentration of 100 ng/ml. this activity suggests that thiadiazine derivatives could be considered as potential antileishmanial compounds. | 2004 | 15273809 |
| phenyl substitution of furamidine markedly potentiates its anti-parasitic activity against trypanosoma cruzi and leishmania amazonensis. | furamidine (db75) and related unfused aromatic diamidines have proven useful for the treatment of parasitic infections. these compounds were primarily developed to combat infections by pneumocystis carinii and african trypanosomes but they are also active against other parasites. here we have investigated the in vitro effects of db75 and its phenyl-substituted analog db569 on two kinetoplastid haemoflagellates trypanosomatidae: trypanosoma cruzi and leishmania (l) amazonensis. the phenyl-amidine ... | 2004 | 15276066 |
| th1 and th2 immunological profile induced by cysteine proteinase in murine leishmaniasis. | this study evaluated the immune response to three synthetic peptides (pi, vmveqvicfd; pii, vggglcfe; piii, pyflgsimntchyt) from the cooh-terminal region of leishmania amazonensis cysteine proteinases, in balb/c- and cba-infected mice with this parasite. only balb/c mice, previously inoculated with pi, showed a distinct exacerbation of the lesion. blastogenesis assays were performed with lymph node cells from the group of mice infected with l. amazonensis, but not inoculated with the peptides, an ... | 2004 | 15279623 |
| il-5-induced eosinophils suppress the growth of leishmania amazonensis in vivo and kill promastigotes in vitro in response to either il-4 or ifn-gamma. | in il-5 transgenic mice (c3h/hen-tgn(il-5)-imeg), in which 50% of peripheral blood leukocytes are eosinophils, the development of infection by leishmania amazonensis was clearly suppressed. to determine mechanistically how this protozoan parasite is killed, we performed in vitro killing experiments. either il-4 or ifn-gamma effectively stimulated eosinophils to kill leishmania amazonensis promastigotes, and most of the killing was inhibited by catalase but not by the no inhibitor l-n5-(1-iminoet ... | 2004 | 15294090 |
| effect of the lysophospholipid analogues edelfosine, ilmofosine and miltefosine against leishmania amazonensis. | analysis of the effect of edelfosine, ilmofosine and miltefosine on leishmania amazonensis and of potential targets of these lysophospholipid analogues. | 2004 | 15329361 |
| the t-cell anergy induced by leishmania amazonensis antigens is related with defective antigen presentation and apoptosis. | leishmania amazonensis is the main agent of diffuse cutaneous leishmaniasis, a disease associated with anergic immune responses. in this study we show that the crude antigen of leishmania amazonensis (laag) but not l. braziliensis promastigotes (lbag) contains substances that suppress mitogenic and spontaneous proliferative responses of t cells. the suppressive substances in laag are thermoresistant (100 degrees c/1h) and partially dependent on protease activity. t cell anergy was not due to a d ... | 2004 | 15334250 |
| characterisation of a new leishmania meta gene and genomic analysis of the meta cluster. | the meta1 gene of leishmania is upregulated in metacyclic promastigotes and encodes a 12 kda virulence-related protein, conserved in all leishmania species analysed. in this study, the genomic region adjacent to the leishmania amazonensis meta1 gene was characterised and compared to the leishmania major meta1 locus as well as to syntenic loci identified in trypanosoma brucei and trypanosoma cruzi. three new genes expressed with increased abundance of steady state mrna in l. amazonensis promastig ... | 2004 | 15336424 |
| protein kinase a activity is associated with metacyclogenesis in leishmania amazonensis. | because of the importance of cell signalling processes in proliferation and differentiation, the adenylate cyclase pathway was studied, specifically the protein kinase a (pka) in leishmania amazonensis. the pkas of soluble (sf) and enriched membrane fractions (mf) from infective/non-infective promastigotes and axenic amastigotes were assayed. in order to purify the pka molecule, fractions were chromatographed on deae-cellulose columns and the phosphorylative activity was evaluated using [gamma(3 ... | 2004 | 15338471 |
| does the leishmania major paradigm of pathogenesis and protection hold for new world cutaneous leishmaniases or the visceral disease? | parasitic protozoa of the genus leishmania have provided a useful perspective for immunologists in terms of host defense mechanisms critical for the resolution of infection caused by intracellular pathogens. these organisms, which normally reside in a late endosomal, major histocompatibility complex (mhc) class ii(+) compartment within host macrophages cells, require cd4(+) t-cell responses for the control of disease. the paradigm for the cd4(+) t-helper 1 (th1)/th2 dichotomy is largely based on ... | 2004 | 15361243 |
| leishmania (leishmania) amazonensis: purification and characterization of a promastigote serine protease. | pathogenic protozoan proteases play crucial roles in the host-parasite interaction, and its characterization contributes to the understanding of protozoan disease mechanisms. a leishmania amazonensis promastigote protease was purified 36-fold, using aprotinin-agarose affinity chromatography and gel filtration high performance liquid chromatography, yielding a total recovery of 49%. the molecular mass of active enzyme obtained from native gel filtration hplc and sds-page under conditions of reduc ... | 2004 | 15363943 |
| immune response induced by new world leishmania species in c57bl/6 mice. | in the present study, c57bl/6 mice were inoculated with metacyclic leishmania amazonensis or l. braziliensis promastigotes. while these animals were capable of controlling the infection by l. braziliensis, they developed chronic lesions with elevated numbers of parasites when infected by l. amazonensis. the differences in parasite control were associated with a decreased production of ifn-gamma and tnf by lymph node cells from l. amazonensis-infected mice. furthermore, these animals presented de ... | 2004 | 15378352 |
| influence of h2 complex and non-h2 genes on progression of cutaneous lesions in mice infected with leishmania amazonensis. | susceptibility to infection with leishmania amazonensis promastigotes was examined in six b10 congenic mouse strains, including c57bl/10j (h2b), b10.br (h2k), b10.m (h2f), b10.s (h2s), b10.riii (h2r), and b10.d2 (h2d). all strains of mice developed skin nodules with punch-out ulcers by 8 weeks post-infection, but b10.m and b10.s mice showed resolution of cutaneous leishmaniasis lesions by 16 weeks post-infection. in addition, the skin lesions were much larger in balb congenic mice than in b10 an ... | 2004 | 15468528 |
| toxoplasma gondii exposes phosphatidylserine inducing a tgf-beta1 autocrine effect orchestrating macrophage evasion. | toxoplasmosis is a worldwide disease caused by toxoplasma gondii. activated macrophages control t. gondii growth by nitric oxide (no) production. however, t. gondii active invasion inhibits no production, allowing parasite persistence. here we show that the mechanism used by t. gondii to inhibit no production persisting in activated macrophages depends on phosphatidylserine (ps) exposure. masking ps with annexin-v on parasites or activated macrophages abolished no production inhibition and paras ... | 2004 | 15474490 |
| antileishmanial pyrazolopyridine derivatives: synthesis and structure-activity relationship analysis. | three series of 4-anilino-1h-pyrazolo[3,4-b]pyridine-5-carboxylic esters were synthesized as part of a program to study potential anti-leishmania drugs. these compounds were obtained by a condensation reaction of 4-chloro-1h-pyrazolo[3,4-b]pyridine with several aniline derivatives. some of them were also obtained by an alternative pathway involving a mannich-type reaction. the hydrophobic parameter, log p, was determined by shake-flask methodology, and using the hansch-fujita addictive hydrophob ... | 2004 | 15481980 |
| protection of c3heb/fej mice against leishmania amazonensis challenge after previous leishmania major infection. | the th1 response elicited in mice infected with leishmania major has been used as a model to characterize cellular immune defects associated with l. amazonensis infection. however, it is not known if the immune response associated with the infection by virulent l. major parasites can promote resistance to a subsequent l. amazonensis infection. our data demonstrate that c3heb/fej mice infected subcutaneously with virulent l. major are resistant to an l. amazonensis challenge. the healing phenotyp ... | 2004 | 15516635 |
| trypanosomatid flagellum biogenesis: arl-3a is involved in several species. | overexpression in leishmania amazonensis promastigotes of the gtpase-deficient small g protein ldarl-3a-q70l specifically provokes the loss of the flagella without affecting cell viability and body size. however, motility is lost and, remarkably, cells do not survive in the insect vector lutzomyia longipalpis gut, leading to interruption of parasite transmission. we report here that overexpression of the same protein in leishmania major, leishmania donovani, and crithidia fasciculata also led to ... | 2004 | 15582509 |
| antibody response in patients with cutaneous leishmaniasis infected by leishmania (viannia) braziliensis or leishmania (viannia) guyanensis in brazil. | the antibody response against leishmania (leishmania) amazonensis crude antigen was measured through the indirect immunofluorescent assay (ifa) and the immunoenzymatic assay (elisa) in 114 patients with cutaneous leishmaniasis (cl) in brazil. fifty-four patients were infected by leishmania (viannia) braziliensis, and 60 patients had l. (v.) guyanensis infection. patients were comparable by age, sex, disease duration and the montenegro skin test diameter. l. (v.) braziliensis-infected patients sh ... | 2005 | 15589797 |
| hypoxia modulates expression of the 70-kd heat shock protein and reduces leishmania infection in macrophages. | hypoxia, a microenvironmental factor present in diseased tissues, has been recognized as a specific metabolic stimulus or a signal of cellular response. experimental hypoxia has been reported to induce adaptation in macrophages such as differential migration, elevation of proinflammatory cytokines and glycolytic enzyme activities, and decreased phagocytosis of inert particles. in this study we demonstrate that although exposure to hypoxia (5% o2, 5% co2, and balanced n2) did not change macrophag ... | 2004 | 15591782 |
| cell structure and cytokinesis alterations in multidrug-resistant leishmania (leishmania) amazonensis. | multidrug-resistant leishmania (leishmania) amazonensis may be obtained by in vitro selection with vinblastine. in order to determine whether this phenotype is linked to structural alterations, we analyzed the cell architecture by electron microscopy. the vinblastine resistant cl2 clone of l. (l.) amazonensis, but not wild-type parasites, showed a cytokinesis dysfunction. the cl2 promastigotes had multiple nuclei, kinetoplasts and flagella, suggesting that vinblastine resistance may be associate ... | 2004 | 15592939 |
| expression of hypoxia-inducible factor-1alpha in the cutaneous lesions of balb/c mice infected with leishmania amazonensis. | the hypoxia-inducible factor-1alpha (hif-1alpha) is expressed in response to hypoxia and has been recently demonstrated in a variety of cells such as tumor cells and tumor-associated macrophages. several characteristics of leishmanial lesions in humans and in animal models, such as microcirculation impairment, metabolic demand for leukocyte infiltration into infected tissue, parasite proliferation, and secondary bacterial infection, are strong indications of a hypoxic microenvironment in the les ... | 2005 | 15596060 |
| antileishmanial activity of parthenolide, a sesquiterpene lactone isolated from tanacetum parthenium. | the in vitro activity of parthenolide against leishmania amazonensis was investigated. parthenolide is a sesquiterpene lactone purified from the hydroalcoholic extract of aerial parts of tanacetum parthenium. this isolated compound was identified through spectral analyses by uv, infrared, (1)h and (13)c nuclear magnetic resonance imaging, dept (distortionless enhancement by polarization transfer), cosy (correlated spectroscopy), hmqc (heteronuclear multiple-quantum coherence), and electron spray ... | 2005 | 15616293 |
| screening of new caledonian and vanuatu medicinal plants for antiprotozoal activity. | sixty-seven extracts of 30 medicinal plants traditionally used in new caledonia or vanuatu by healers to treat inflammation, fever and in cicatrizing remedies were evaluated in vitro for their antiprotozoal activity against leishmania donovani, leishmania amazonensis and trypanosoma cruzi. among the selected plants, pagiantha cerifera was the most active against both leishmania species; four extracts were active against promastigotes of leishmania donovani at ec(50) values inferior to 5 microg/m ... | 2004 | 15619580 |
| characterisation of a developmentally regulated amino acid transporter gene from leishmania amazonensis. | the metabolism of protozoan parasites of the leishmania genus is strongly based on amino acid consumption, but little is known about amino acid uptake in these organisms. in the present work, we identified a leishmania amazonensis gene (la-pat1) encoding a putative amino acid transporter that belongs to the amino acid/auxin permease family, a group of h(+)/amino acid symporters. this single copy gene is upregulated in amastigotes, the life cycle stage found in the mammalian host. la-pat1 putativ ... | 2005 | 15621448 |
| bioluminescent leishmania expressing luciferase for rapid and high throughput screening of drugs acting on amastigote-harbouring macrophages and for quantitative real-time monitoring of parasitism features in living mice. | in this study, we have established conditions for generating leishmania amazonensis recombinants stably expressing the firefly luciferase gene. these parasites produced significant bioluminescent signals for both in vitro studies and the development of an in vivo model, allowing the course of the parasitism to be readily monitored in real time in the living animals such as laboratory mice. first, a model was established, using parasite-infected mouse macrophages for rapidly determining the activ ... | 2005 | 15679841 |
| effects of hyperbaric oxygen on leishmania amazonensis promastigotes and amastigotes. | in the present study, we evaluated the effects of hyperbaric oxygen (hbo) exposure in both leishmania amazonensis life stages (promastigotes and amastigotes) and on macrophage cultures infected with the parasite. hbo treatment protocols, which can be tolerated by humans and animals, induced irreversible metabolic damage and affected parasite morphology, growth and ability to transform. the observation that the antioxidant n-acetylcysteine (nac) prevents some of these deleterious effects indicate ... | 2005 | 15710544 |
| feline leishmaniasis due to leishmania (leishmania) amazonensis in mato grosso do sul state, brazil. | a case of leishmaniasis in a domestic cat (felis domesticus) is described. the animal showed a single, nodular lesion on the nose and many nodules of different size on the ears and digital regions of all the paws. diagnosis was made by microscopic detection of amastigotes in giemsa-stained smears from the lesions. by monoclonal antibodies the aetiological agent was identified as leishmania (leishmania) amazonensis, one of the seven species implicated in human leishmaniasis in brazil. the clinica ... | 2004 | 15725531 |
| flow cytometric assessment of leishmania spp metacyclic differentiation: validation by morphological features and specific markers. | characterization of infective metacyclic promastigotes of leishmania spp can be an essential step in several experimental protocols. metacyclic forms of all leishmania species display a typical morphology with short, narrow cell body, and an elongated flagellum. this feature suggests that metacyclics can be distinguished from procyclic forms by non-fluorimetric flow cytometric parameters thus enabling the follow-up of their appearance and acquisition of specific properties, during metacyclogenes ... | 2005 | 15804377 |
| a new heptasubstituted (e)-aurone glucoside and other aromatic compounds of gomphrena agrestis with biological activity. | a new aurone 1 and two known substances, aurantiamide acetate (2) and tiliroside (3), were isolated from the ethanolic extract of gomphrena agrestis. the structural determination of 1 was based on spectroscopic and spectrometric data. the substance was defined as (e)-3'-o-beta-d-glucopyranosyl-4,5,6,4'-tetrahydroxy-7,2'-dimethoxyaurone. biological activity of the ethanolic crude extract and isolated compounds against bacteria, fungi and leishmania amazonensis amastigotes was evaluated. this appe ... | 2004 | 15813368 |
| a serine protease from a detergent-soluble extract of leishmania (leishmania) amazonensis. | proteases mediate important crucial functions in parasitic diseases, and their characterization contributes to the understanding of host-parasite interaction. a serine protease was purified about 43-fold with a total recovery of 60% from a detergent-soluble extract of promastigotes of leishmania amazonensis. the purification procedures included aprotinin-agarose affinity chromatography and gel filtration high performance liquid chromatography. the molecular mass of active enzyme was 110 kda by n ... | 2004 | 15813385 |
| [immunoglobulin isotype and igg subclass profiles in american tegumentary leishmaniasis]. | the present work investigated the serum antibody profiles in 37 patients with american tegumentary leishmaniasis, who were attended at hospital de clinicas - universidade federal de uberlandia, mg, brazil. the immunoglobulin class and igg subclass profiles were analyzed by indirect elisa using leishmania (leishmania) amazonensis soluble antigen. the antibody avidity was determined by 6 m urea treatment after incubation with immunoenzymatic conjugate. it was observed that 97% of the serum samples ... | 2005 | 15821787 |
| antileishmanial activity of the terpene nerolidol. | the activity of nerolidol, a sesquiterpene used as a food-flavoring agent and currently under testing as a skin penetration enhancer for the transdermal delivery of therapeutic drugs, was evaluated against leishmania species. nerolidol inhibited the growth of leishmania amazonensis, l. braziliensis, and l. chagasi promastigotes and l. amazonensis amastigotes with in vitro 50% inhibitory concentrations of 85, 74, 75, and 67 microm, respectively. the treatment of l. amazonensis-infected macrophage ... | 2005 | 15855481 |
| late cutaneous metastases in c3h scid mice infected with leishmania amazonensis. | the biological behavior of leishmania amazonensis in the mammalian host is highly variable, resulting in local to diffuse cutaneous lesions that sometimes metastasize. inflammation and, more specifically, cd4+ t cells have been shown to enhance metastases in mice infected with l. amazonensis, suggesting that the process may be lymphocyte mediated. however, we document, in this study, the development of multiple cutaneous metastases in c3h scid mice infected with l. amazonensis. this shows that f ... | 2005 | 15856912 |
| sand fly specificity of saliva-mediated protective immunity in leishmania amazonensis-balb/c mouse model. | immune response of balb/c mice to the salivary antigens of sand flies was found to vary with different species used, i.e. phlebotomus papatasi, phlebotomus sergenti and lutzomyia longipalpis. exposure of mice to bites of these sand flies elicits production of antibodies, which are largely specific to different saliva antigens previously identified as unique to the respective fly species. when immunized intradermally (i.d.) with salivary gland lysates (sgl) of l. longipalpis, balb/c mice develope ... | 2005 | 15866511 |
| studies on quinones. part 39: synthesis and leishmanicidal activity of acylchloroquinones and hydroquinones. | acylhydroquinone-based compounds are attractive targets for the design of new leishmanicidal drugs. we have previously described sesquiterpene quinones and hydroquinones series, which exhibit different degree of potency against leishmania amazonensis. the present study details the preparation of acylchloroquinones and hydroquinones possessing lipophilic substituents and examines their in vitro activity against intracellular l. amazonensis amastigotes. the quinone or hydroquinone nucleus is essen ... | 2005 | 15876538 |
| effect of a juvenile hormone analogue on leishmania amazonensis and leishmania braziliensis. | | 2005 | 15888299 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| leishmania amazonensis: early proteinase activities during promastigote-amastigote differentiation in vitro. | leishmania proteinase activity is known as parasite differentiation marker, and has been considered relevant for leishmanial survival and virulence. these properties suggest that leishmania proteinases can be promising targets for development of anti-leishmania drugs. here, we analyze the activities of four proteinases during the early phase of the leishmania amazonensis promastigotes differentiation into amastigotes induced by heat shock. we have examined activities of cysteine-, metallo-, seri ... | 2004 | 15639138 |
| an effective diaryl derivative against leishmania amazonensis and its influence on the parasite x macrophage interaction. | the activity of several diarylheptanoid derivatives (curcuminoids) was previously evaluated against leishmania amazonensis promastigotes and among them the most active compound was 5-hydroxy-7- (4-hydroxy-3-methoxyphenyl)-1-(4-methoxyphenyl)-1,4,6-heptatrien-3-one. this study was carried out to investigate the influence of this diaryl derivative on the infective promastigotes and balb/c mice peritoneal macrophage interaction. the potential in vitro toxicity was also evaluated. promastigotes pret ... | 2004 | 15648659 |
| activity of a paromomycin hydrophilic formulation for topical treatment of infections by leishmania (leishmania) amazonensis and leishmania (viannia) braziliensis. | studies on in vitro skin permeation and in vivo anti-leishmanial activity in mice experimentally infected with leishmania (leishmania) major pointed out to the potential of a new paromomycin (pa) formulation (hydrophilic gel) for treatment of cutaneous leishmaniasis (cl). in this study, the activity of this formulation was evaluated in animals experimentally infected by leishmania species that prevail in the new world. pa gel activity was compared to antimony treatment, since it is still the fir ... | 2004 | 15652330 |
| real-time measurements of membrane surface dynamics on macrophages and the phagocytosis of leishmania parasites. | defocusing microscopy was used for real-time observation and quantification of membrane surface dynamics in murine bone marrow macrophages. small random membrane fluctuations (srmf), possibly metabolic driven, were detected uniformly over all membrane surface. morphological and dynamical parameters of ruffles, such as shape, dimensions, and velocity of propagation, were analyzed. optical tweezers were used to promote phagocytosis of single leishmania amazonensis amastigotes by selected macrophag ... | 2005 | 15652336 |
| use of proteolytic enzymes as an additional tool for trypanosomatid identification. | the expression of proteolytic activities in the trypanosomatidae family was explored as a potential marker to discriminate between the morphologically indistinguishable flagellates isolated from insects and plants. we have comparatively analysed the proteolytic profiles of 19 monoxenous trypanosomatids (herpetomonas anglusteri, h. samuelpessoai, h. mariadeanei, h. roitmani, h. muscarum ingenoplastis, h. muscarum muscarum, h. megaseliae, h. dendoderi, herpetomoas sp., crithidia oncopelti, c. dean ... | 2005 | 15700759 |
| 2-propen-1-amine derivatives and their synthetic intermediates: activity against pathogenic trypanosomatids. | the potential activity of three new derivatives of 3-(4'-y-[1,1'-biphenyl]-4-yl)-3-(4-x-phenyl)-n,n-dimethyl-2-propen-1-amine (2-pams) was assayed against trypanosoma cruzi and leishmania amazonensis. they showed higher activity against trypomastigotes and epimastigotes of t. cruzi than the standard drugs, crystal violet and nifurtimox. besides these derivatives, a series of eleven 2-pams derivatives and the corresponding intermediates, biphenyl methanones (bpms) were assayed against promastigot ... | 2004 | 15700843 |
| leishmania (viannia) subgenus kdna amplification for the diagnosis of mucosal leishmaniasis. | the utility of 2 polymerase chain reaction (pcr)-based assays amplifying genus or viannia subgenus leishmania minicircle kdna for the diagnostics of ml was assessed. the viannia subgenus product was yielded after pcr from isolates of l. (viannia) braziliensis, l. (viannia) colombiensis, and l. (viannia) guyanensis, whereas no product was obtained with the non-viannia-pertaining species: l. (leishmania) amazonensis, l. (leishmania) donovani, and l. (leishmania) chagasi. with both assays, 11 of 13 ... | 2005 | 15766604 |
| [immunization with leishmania amazonensis subgenomic libraries protects balb/c mice against the challenge]. | a genomic library of leishmania amazonensis in expression vector of eukaryote cells (pef1hisa, pef1hisb, pef1hisc) was prepared. also two subgenomic libraries having each 500 clones approximately were created and balb/c mice were immunized with 50 mg/0,1 ml of dna from each. two immunizations were administered intramuscularly at 15-day interval. groups of control mice were immunized with dna from empty plasmid pef1his, with soluble parasite antigen (100 mg/0,1 ml) and saline solution. the size o ... | 2004 | 15846906 |
| [building of a genomic library of leishmania amazonensis and its expression in balb/c mice's muscle]. | a genomic library of leishaminia amazonensis was built through a pcdna3 vector, with expression promoter in eukaryot cells, to contribute to the application of immunization technology with nucleic acids in leishmaniasis. to show the expression genomic library in the muscles of mice immunized with it, the indirect immunofluoresce technique was used. a mix of sera with high antileishmania titers from an area where l.braziliensis infection is predominant was used as primary antibody. a library of 8 ... | 2001 | 15846918 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| [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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 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 |