Publications
| Title | Abstract | Year(sorted ascending) Filter | PMID Filter |
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| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 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 |
| 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 |
| 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 |
| 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 |
| [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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| [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 |
| 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 |
| 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 |
| synthesis of new 4-(e)-alkenylpyrrolo[1,2-a]quinoxalines as antileishmanial agents by suzuki-miyaura cross-coupling reactions. | a series of new 4-(e)-alkenylpyrrolo[1,2-a]quinoxaline derivatives, structural analogues of alkaloid chimanine b, was synthesized in good yields using efficient palladium(0)-catalyzed suzuki-miyaura cross-coupling reactions. these new compounds were tested for in vitro antiparasitic activity upon leishmania amazonensis and leishmania infantum strains. biological results showed activity against the promastigote forms of l. amazonensis and l. infantum with ic50 ranging from 0.5 to 7 microm. from a ... | 2007 | 18035821 |
| expression of hypoxia-inducible factor 1alpha in mononuclear phagocytes infected with leishmania amazonensis. | increasing evidence indicates that hypoxia-inducible factor 1alpha (hif-1alpha) can be upregulated in different cell types by nonhypoxic stimuli such as growth factors, cytokines, nitric oxide, lipopolysaccharides and a range of infectious microorganisms. in this study, the ability of the following mononuclear phagocytes to express hif-1alpha is reported: mouse macrophages (mmphi), human macrophages (hmphi) and human dendritic cells (dc), parasitized in vitro with leishmania amazonensis; as asse ... | 2007 | 17983667 |
| unveiling pathways used by leishmania amazonensis amastigotes to subvert macrophage function. | this article provides a summary and discussion of properties of leishmania amazonensis-loaded mouse macrophages. it illustrates how high-throughput analysis is expected to contribute to deciphering features displayed by macrophages when they are subverted as host cells for replicating leishmania amastigotes. firstly, we discuss features of mouse mononuclear phagocytes in steady-state conditions, including the phagocytosis of apoptotic cells. secondly, we discuss results from ongoing investigatio ... | 2007 | 17850482 |
| structure-activity relationship of antileishmanials neolignan analogues. | twenty-two synthetic analogues of neolignans comprising beta-ketoethers and beta-ketosulfides were obtained from condensation reactions among beta-bromoketones and phenols or thiophenols, respectively, in basic solutions, and assayed in vitro for activity against intracellular leishmania amazonensis and leishmania donovani amastigotes, the causative agents of cutaneous and visceral leishmaniasis. the highest selective activity was found for compounds with sulfur bridges, whereas beta-ketosulphox ... | 2007 | 17888668 |
| evaluation of the leishmanicidal activity of plants used by peruvian chayahuita ethnic group. | a total of 27 ethanolic plant extracts from 27 species were screened for leishmanicidal activity in vitro against leishmania amazonensis. most of the selected species (19) are traditionally used by the chayahuitas, an amazonian peruvian ethnic group, to treat skin affections and/or leishmaniasis. | 2007 | 17889471 |
| synthesis and in vitro evaluation of leishmanicidal and trypanocidal activities of n-quinolin-8-yl-arylsulfonamides. | in the present paper 12 n-quinolin-8-yl-arylsulfonamides synthesized by coupling 8-aminoquinolines with various arylsulfonylchlorides were assayed in vitro against leishmania amazonensis, leishmania chagasi and trypanosoma cruzi strains. this series of new compounds were found to be selective for leishmania spp. promastigote and amastigote forms. the most active compound was the n-(8-quinolyl)-3,5-difluoro-benzenesulfonamide 10 with an ic(50) against l. amazonensis and l. chagasi of 2.12 and 0.4 ... | 2007 | 17889546 |
| leishmania dna is rapidly degraded following parasite death: an analysis by microscopy and real-time pcr. | control of human leishmaniases relies on appropriate diagnosis and reliable methods for monitoring chemotherapy. the current method used for estimation of parasite burden during chemotherapy patient follow-up as well as in pharmacological studies performed in experimental models involves pcr-based assays. compared to time-consuming conventional methods, this type of leishmania dna detection-based method is extremely sensitive, but could fail in distinguishing viable leishmania from slowly degene ... | 2007 | 17890124 |
| leishmania amazonensis infection impairs differentiation and function of human dendritic cells. | dendritic cells (dcs) are of utmost importance in initiating an immune response and may also function as targets for pathogens. the presence of pathogens inside dcs is likely to impair their functions and thus, influence immune responses. in the present report, we evaluated the impact of the presence of leishmania amazonensis during differentiation and maturation of human monocyte-derived dcs. the presence of live l. amazonensis parasites during dc differentiation led to a significant decrease i ... | 2007 | 17890507 |
| analysis and chromosomal mapping of leishmania (leishmania) amazonensis amastigote expressed sequence tags. | the characterization of expressed sequence tags (ests) generated from a cdna library of leishmania (leishmania) amazonensis amastigotes is described. the sequencing of 93 clones generated new l. (l.) amazonensis ests from which 32% are not related to any other sequences in database and 68% presented significant similarities to known genes. the chromosome localization of some l. (l.) amazonensis ests was also determined in l. (l.) amazonensis and l. (l.) major. the characterization of these ests ... | 2007 | 17923999 |
| oligopeptidase b from leishmania amazonensis: molecular cloning, gene expression analysis and molecular model. | serine oligopeptidases of trypanosomatids are emerging as important virulence factors and therapeutic targets in trypanosome infections. a complete open reading frame of oligopeptidase b from leishmania amazonensis was amplified with polymerase chain reaction with gradient annealing temperatures using primers designed for the oligopeptidase b gene from l. major. the 2,196-bp fragment coded for a protein of 731 amino acids with a predicted molecular mass of 83.49 kda. the encoded protein (la_opb) ... | 2007 | 18074461 |
| rna polymerase i promoter and splice acceptor site recognition affect gene expression in non-pathogenic leishmania species. | leishmania (sauroleishmania) tarentolae has biotechnological potential for use as live vaccine against visceral leishmaniasis and as a system for the over expression of eukaryotic proteins that possess accurate post-translational modifications. for both purposes, new systems for protein expression in this non-pathogenic protozoan are necessary. the ribosomal rna promoter proved to be a stronger transcription driver since its use yielded increased levels of recombinant protein in organisms of bot ... | 2007 | 18060313 |
| protective effect of lectin from synadenium carinatum on leishmania amazonensis infection in balb/c mice. | the protective effect of the synadenium carinatum latex lectin (scll), and the possibility of using it as an adjuvant in murine model of vaccination against american cutaneous leishmaniasis, were evaluated. balb/c mice were immunized with the lectin scll (10, 50, 100 microgram/animal) separately or in association with the soluble leishmania amazonensis antigen (sla). after a challenge infection with 10(6) promastigotes, the injury progression was monitored weekly by measuring the footpad swellin ... | 2007 | 18165707 |
| the activity of azithromycin against leishmania (viannia) braziliensis and leishmania (leishmania) amazonensis in the golden hamster model. | new therapeutic alternatives against leishmaniasis remain a priority. the activity of azithromycin against leishmania (leishmania) major has been previously demonstrated. different responses among species of leishmania make species-specific drug screening necessary. the activity of azithromycin against leishmania (viannia) braziliensis and leishmania (leishmania) amazonensis was evaluated in golden hamsters infected through footpad injections of metacyclic promastigotes, and compared with untrea ... | 2007 | 18200413 |
| 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 |
| 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 |
| 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 |
| 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 |
| anti-leishmania activity of semi-purified fraction of jacaranda puberula leaves. | the crude methanolic extract from leaves of jacaranda puberula showed activity against leishmania (leishmania) amazonensis. the extract presented active against promastigote forms with an inhibitory concentration 50% (ic(50)) value of 88.0 mug/ml, but only moderated activity against amastigote forms; however in higher concentrations the extract showed cytotoxic effects. the bio-guided chromatographic fractionation the crude methanolic extract against amastigotes yielded a fraction with an ic(50) ... | 2007 | 17390147 |
| macrophage killing of leishmania amazonensis amastigotes requires both nitric oxide and superoxide. | the requirements for effective and efficient intracellular killing of leishmania amazonensis by activated macrophages are unknown. despite resistance to the arginase inhibitor loha by intracellular l. amazonensis amastigotes, enhanced replication did not account for the relative resistance of this parasite to macrophage activation. herein we report that the presence of both superoxide and nitric oxide is necessary for efficient killing of l. amazonensis amastigotes within lps/ifn-gamma-activated ... | 2007 | 17426168 |
| effects of brazilian propolis on leishmania amazonensis. | leishmaniasis, an endemic parasitosis that leads to chronic cutaneous, mucocutaneous or visceral lesions, is part of those diseases, which still requires improved control tools. propolis has shown activities against different bacteria, fungi, and parasites. in this study we investigated the effect of four ethanolic extracts of typified propolis collected in different brazilian states, on leishmania amazonensis performing assays with promastigote forms, extracellular amastigotes, and on infected ... | 2007 | 17426888 |
| a trial of immunotherapy against leishmania amazonensis infection in vitro and in vivo with z-100, a polysaccharide obtained from mycobacterium tuberculosis, alone or combined with meglumine antimoniate. | to determine the efficacy and the immunomodulatory function of z-100 alone or combined with meglumine antimoniate on leishmania amazonensis infection. | 2007 | 17439977 |
| synthesis and evaluation of new difluoromethyl azoles as antileishmanial agents. | several compounds of great pharmacological interest contain the triazole and imidazole rings. in order to find new drugs with antileishmanial activity we have synthesized and evaluated new imidazole and triazole compounds carrying either the carbaldehyde or the difluoromethylene functionalities against promastigote forms of leishmania amazonensis. among the compounds tested difluoromethylene azoles 4b and 8f have inhibited the parasite growth significantly. our results show that the introduction ... | 2007 | 17445951 |
| oral leishmaniasis: a clinicopathological study of 11 cases. | leishmaniasis is a parasitic disease with diverse clinical manifestations, and considered a public health problem in endemic countries such as brazil. mucosal lesions usually involve the upper respiratory tract, with a predilection for nose and larynx. oral involvement is unusual and in most cases it becomes evident after several years of resolution of the original cutaneous lesions. oral lesions classically appear as mucosal ulcerations, mainly in the hard or soft palate. this report describes ... | 2007 | 17448219 |
| spirolactone iridoids might be responsible for the antileishmanial activity of a peruvian traditional remedy made with himatanthus sucuuba (apocynaceae). | extracts of seven medicinal plants used specifically against cutaneous leishmaniasis in the madre de dios region of peru were evaluated in vitro against promastigote and axenic amastigote forms of leishmania amazonensis. one of them showed interesting leishmanicidal activities (ic(50)=5 microg/ml in amastigotes). bio-guided isolation of the stem bark's ethanol extract of himatanthus sucuuba (spruce ex müll. arg.) woodson (apocynaceae) afforded the spirolactone iridoids isoplumericin and plumeric ... | 2007 | 17459622 |
| leishmania amazonensis: pkc-like protein kinase modulates the (na++k+)atpase activity. | the present study aimed to identify the presence of protein kinase c-like (pkc-like) in leishmania amazonensis and to elucidate its possible role in the modulation of the (na(+)+k(+))atpase activity. immunoblotting experiments using antibody against a consensus sequence (ac 543-549) of rabbit protein kinase c (pkc) revealed the presence of a protein kinase of 80 kda in l. amazonensis. measurements of protein kinase activity showed the presence of both (ca(2+)-dependent) and (ca(2+)-independent) ... | 2007 | 17475255 |
| antileishmanial activity of crude extract and coumarin from calophyllum brasiliense leaves against leishmania amazonensis. | infections by protozoans of the genus leishmania are a major worldwide health problem, with high endemicity in developing countries. the drugs of choice for the treatment of leishmaniasis are the pentavalent antimonials, which show renal and cardiac toxicity. as part of a search for new drugs against leishmaniasis, we evaluated the in vitro leishmanicidal activity of the (-) mammea a/bb. the compound (-) mammea a/bb is a coumarin-type mammea purified from a dichloromethane crude extract of leave ... | 2007 | 17483964 |
| leishmania replication protein a-1 binds in vivo single-stranded telomeric dna. | replication protein a (rpa) is a highly conserved heterotrimeric single-stranded dna-binding protein involved in different events of dna metabolism. in yeast, subunits 1 (rpa-1) and 2 (rpa-2) work also as telomerase recruiters and, in humans, the complex unfolds g-quartet structures formed by the 3' g-rich telomeric strand. in most eukaryotes, rpa-1 and rpa-2 bind dna using multiple ob fold domains. in trypanosomatids, including leishmania, rpa-1 has a canonical ob fold and a truncated rfa-1 str ... | 2007 | 17498665 |
| larbp38: a leishmania amazonensis protein that binds nuclear and kinetoplast dnas. | leishmania amazonensis causes a wide spectrum of leishmaniasis. there are no vaccines or adequate treatment for leishmaniasis, therefore there is considerable interest in the identification of new targets for anti-leishmania drugs. the central role of telomere-binding proteins in cell maintenance makes these proteins potential targets for new drugs. in this work, we used a combination of purification chromatographies to screen l. amazonensis proteins for molecules capable of binding double-stran ... | 2007 | 17506988 |
| oligopeptidase b from l. amazonensis: molecular cloning, gene expression analysis and molecular model. | serine oligopeptidases of trypanosomatids are emerging as important virulence factors and therapeutic targets in trypanosome infections. a complete open reading frame of oligopeptidase b from leishmania amazonensis was amplified with polymerase chain reaction with gradient annealing temperatures using primers designed for the oligopeptidase b gene from l. major. the 2,196-bp fragment coded for a protein of 731 amino acids with a predicted molecular mass of 83.49 kda. the encoded protein (la_opb) ... | 2007 | 17530480 |
| role of leishmania (leishmania) amazonensis amastigote glycosphingolipids in macrophage infectivity. | the role of glycosphingolipids (gsls) present in amastigote forms of leishmania (leishmania) amazonensis during infection of macrophages was analyzed, with particular emphasis on gsls presenting the terminal galpss1-3galpa disaccharide. macrophage invasion by l. (l.) amazonensis amastigotes was reduced by 37% when the disaccharide galpss1-3galp (1 mm) was added to the culture medium. the putative macrophage receptor/lectin for ss-gal-globotriaosylceramide (galpss1-3galpa1-4galpss1-4glc pss1-1cer ... | 2007 | 17581678 |
| tamoxifen is effective against leishmania and induces a rapid alkalinization of parasitophorous vacuoles harbouring leishmania (leishmania) amazonensis amastigotes. | this study was performed to investigate the activity of tamoxifen, an antioestrogen widely used in the treatment of breast cancer, against leishmania. | 2007 | 17584801 |
| genetic diversity of leishmania amazonensis strains isolated in northeastern brazil as revealed by dna sequencing, pcr-based analyses and molecular karyotyping. | leishmania (leishmania) amazonensis infection in man results in a clinical spectrum of disease manifestations ranging from cutaneous to mucosal or visceral involvement. in the present study, we have investigated the genetic variability of 18 l. amazonensis strains isolated in northeastern brazil from patients with different clinical manifestations of leishmaniasis. parasite dna was analyzed by sequencing of the its flanking the 5.8 s subunit of the ribosomal rna genes, by rapd and ssr-pcr and by ... | 2007 | 17584940 |
| effect of insulin-like growth factor-i on leishmania amazonensis promastigote arginase activation and reciprocal inhibition of nos2 pathway in macrophage in vitro. | we showed previously that insulin-like growth factor (igf)-i induces an exacerbation of the lesion development in experimental cutaneous leishmaniasis favouring parasite growth within host macrophages. here we studied the effect of igf-i in vitro in balb/c mouse peritoneal macrophages infected with stationary phase leishmania amazonensis promastigotes. igf-i was used to pre-incubate either macrophage or parasite before infection of the macrophages or adding it at the start of the leishmania-macr ... | 2007 | 17635806 |
| evaluation of immune responses and protection induced by a2 and nucleoside hydrolase (nh) dna vaccines against leishmania chagasi and leishmania amazonensis experimental infections. | several antigens have been tested as vaccine candidates against leishmania infections but controversial results have been reported when different antigens are co-administered in combined vaccination protocols. immunization with a2 or nucleoside hydrolase (nh) antigens was previously shown to induce th1 immune responses and protection in balb/c mice against leishmania donovani and l. amazonensis (a2) or l. donovani and l. mexicana (nh) infections. in this work, we investigated the protective effi ... | 2007 | 17644455 |
| anti-leishmanial and immunomodulatory activities of extracts from portulaca hirsutissima and portulaca werdermannii. | ethyl acetate and chloroform extracts from aerial parts of portulaca werdermannii and p. hirsutissima were tested in lymphoproliferation assays and axenic cultures of leishmania amazonensis and trypanosoma cruzi. both extracts of p. werdermannii and p. hirsutissima had a potent inhibitory activity on lymphocyte proliferation. on the contrary, only the chloroformic extract of both plants inhibited l. amazonensis growth, without effect on t. cruzi cultures. these results indicate these portulaca s ... | 2007 | 17651913 |
| leishmania (leishmania) amazonensis infection and dissemination in mice inoculated with stationary-phase or with purified metacyclic promastigotes. | leishmania (leishmania) amazonensis is a protozoan of the american continent that causes localized cutaneous leishmaniasis and, rarely, the diffuse cutaneous form of disease in humans. it has become clear in recent years that the course of leishmania major infection in the mouse model differs when low numbers of purified metacyclic forms are used as inocula in comparison with the traditionally hitherto studied infection models that used large numbers of stationary-phase (sp) promastigotes. the l ... | 2007 | 17655808 |
| comparative studies of the anti-leishmanial activity of three crotalus durissus ssp. venoms. | in this study, we compared the anti-leishmanial activity of three crotalic venoms (crotalus durissus terrificus-cdt, crotalus durissus cascavella-cdca, and crotalus durissus collilineatus-cdcol). different concentrations of each venom incubated with leishmania (leishmania) amazonensis promastigotes were used. cdt venom exhibited a higher anti-leishmanial activity (inhibitory concentration-ic50-value of 4.70+/-1.72 microg/ml) in comparison with that of cdca venom (ic50 value of 9.41+/-1.21 microg ... | 2007 | 17659386 |
| cd8+ t cells are not required for vaccine-induced immunity against leishmania amazonensis in il-12/23p40(-/-) c57bl/6 mice. | vaccine-induced protection against leishmaniasis is largely dependent on cell-mediated type 1 response and il-12-driven ifn-gamma production. surprisingly, our previous data showed that il-12/23p40(-/-) mice could be vaccinated against l. amazonensis and were able to produce limited amounts of ifn-gamma. since the role of cd8+ t in immunization against l. amazonensis is obscure, the aim of this study was to evaluate the effects of cd8+ cells in protection against l. amazonensis in il-12/23p40(-/ ... | 2007 | 17662634 |
| latbp1: a leishmania amazonensis dna-binding protein that associates in vivo with telomeres and gt-rich dna using a myb-like domain. | different species of leishmania can cause a variety of medically important diseases, whose control and treatment are still health problems. telomere binding proteins (tbps) have potential as targets for anti-parasitic chemotherapy because of their importance for genome stability and cell viability. here, we describe latbp1 a protein that has a myb-like dna-binding domain, a feature shared by most double-stranded telomeric proteins. binding assays using full-length and truncated latbp1 combined w ... | 2007 | 17678615 |
| role of interleukin-1beta in activating the cd11c(high) cd45rb- dendritic cell subset and priming leishmania amazonensis-specific cd4+ t cells in vitro and in vivo. | cutaneous leishmaniasis associated with leishmania amazonensis infection is characterized by uncontrolled parasite replication and profound immunosuppression; however, the underlying mechanisms remain largely unclear. one possibility is that the l. amazonensis parasite modulates antigen-presenting cells, favoring the generation of pathogenic th cells that are capable of recruiting leukocytes but insufficient to fully activate their microbicidal activities. to test this possibility, we infected b ... | 2007 | 17682041 |
| experimental leishmania (l.) amazonensis leishmaniasis: characterization and immunogenicity of subcellular fractions. | a technique developed in trypanosoma cruzi biochemical studies was successfully used to fractionate leishmania (leishmania) amazonensis promastigotes. ultrastructural analyses revealed a membrane fraction (mf) associated to subpellicular microtubules, a ribosomal-rich microsomal fraction (micf), and a flagellar fraction (ff) free of associated membrane. all fractions proved to be immunogenic through delayed type hypersensitivity reaction assays. therefore, a protocol was designed to test whether ... | 2007 | 17691027 |
| crude ethanolic extract, lignoid fraction and yangambin from ocotea duckei (lauraceae) show antileishmanial activity. | crude ethanolic extract, lignoid fraction and the purified compound yangambin were obtained from ocotea duckei (lauraceae) and their antileishmanial activity was tested against promastigote forms of leishmania chagasi and leishmania amazonensis cultivated in schneider medium, supplemented with 20% of fetal bovine serum. all substances presented antileishmanial activity with ic50 values of 135.7 microg/ml for the crude ethanolic extract, 26.5 microg/ml for the lignoid fraction and 49.0 microg/ml ... | 2007 | 17708438 |
| sterol methenyl transferase inhibitors alter the ultrastructure and function of the leishmania amazonensis mitochondrion leading to potent growth inhibition. | we describe here the effects of delta(24(25)) sterol methenyl transferase inhibitors (smti) on promastigote and axenic amastigote forms of leishmania amazonensis. when these cells were exposed to 20-piperidin-2-yl-5alpha-pregnan-3beta-20-diol (22,26-azasterol; aza), hydrazone-imidazol-2-yl-5alpha-pregnan-3beta-ol (imi), 20-hydrazone-pyridin-2-yl-5alpha-pregnan-3beta-ol (pyr) or 24(r,s),25-epiiminolanosterol (eil), a concentration- and time-dependent inhibition of growth was observed, with ic(50) ... | 2007 | 17719843 |
| the first records of leishmania (leishmania) amazonensis in dogs (canis familiaris) diagnosed clinically as having canine visceral leishmaniasis from araçatuba county, são paulo state, brazil. | two cases of leishmania (leishmania) amazonensis are reported in the domestic dog (canis familiaris). these are the first records of this parasite in this species. the animals lived in the endemic visceral leishmaniasis area of araçatuba, são paulo state, brazil and were initially diagnosed, on clinical grounds, as having visceral leishmaniasis. attempted parasite isolation from inguinal lymph node aspirates was unsuccessful and the indirect immunofluorescent test for visceral leishmaniasis was ... | 2007 | 17720321 |
| effects of serine protease inhibitors on viability and morphology of leishmania (leishmania) amazonensis promastigotes. | to investigate the importance of serine proteases in leishmania amazonensis promastigotes, we analyzed the effects of classical serine protease inhibitors and a kunitz-type inhibitor, obtained from sea anemone stichodactyla helianthus (shpi-i), on the viability and morphology of parasites in culture. classical inhibitors were selected on the basis of their ability to inhibit l. amazonensis serine proteases, previously described. the n-tosyl-l: -phenylalanine chloromethyl ketone (tpck) and benzam ... | 2007 | 17726617 |
| combined effect of the essential oil from chenopodium ambrosioides and antileishmanial drugs on promastigotes of leishmania amazonensis. | to date, there are no vaccines against leishmania, and chemotherapy remains the mainstay for the control of leishmaniasis. the drugs of choice used for leishmaniasis therapy are significantly toxic, expensive and with a growing frequency of refractory infections. because of these limitations, a combination therapy is the better hope. this work demonstrates that the essential oil from chenopodium ambrosioides shows a synergic activity after incubation in conjunction with pentamidine against proma ... | 2007 | 17823757 |
| 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 |
| 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 |
| 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 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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: 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 |
| 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 |