Publications

axenically cultured amastigote forms as an in vitro model for investigation of antileishmanial agents.	using a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide microassay, previously described as a means of quantifying leishmania amazonensis in vitro at the amastigote stage (d. sereno and j. l. lemesre, parisitol. res., in press), we have compared the activities of seven drugs, including those currently used to treat leishmaniasis, against axenically grown amastigote and promastigote forms of three leishmania species (l. amazonensis, l. mexicana, and l. infantum, responsible for diffu ...	1997	9145854
role of cd4+ t cells in pathogenesis associated with leishmania amazonensis infection.	most inbred strains of mice are susceptible to leishmania amazonensis infection. we have examined the mechanism(s) underlying this generalized susceptibility using mice deficient in t cell development or in the expression of either mhc class i or class ii. in contrast to wild-type c57bl/6 (b6) mice that uniformly developed large ulcerating lesions, mice lacking functional cd4+ t cells (due to targeted disruption of genes for either mhc class ii trans-activator or i-a beta) showed no signs of les ...	1997	9164958
characterization of an antigen from leishmania amazonensis amastigotes able to elicit protective responses in a murine model.	lymphoproliferative responses to an antigen from leishmania amazonensis amastigotes with an apparent molecular mass of 30 kda, termed p30, were evaluated with balb/c mice. the p30 antigen was purified after separation of parasite extracts by sodium dodecyl sulfate-polyacrylamide gel electrophoresis followed by electroelution. lymphoproliferative responses to p30 were obtained by subcutaneous immunization of animals with l. amazonensis amastigote extracts, and maximal stimulation indices were obs ...	1997	9169731
homologues of the 24-kda flagellar ca(2+)-binding protein gene of trypanosoma cruzi are present in other members of the trypanosomatidae family.	a full-length cdna encoding the 24-kda flagellar ca(2+)-binding protein (fcabp) of the dm28c clone of trypanosoma cruzi was cloned and characterized. comparison of the deduced amino acid sequence with those of the fcabps of other t. cruzi strains revealed greater than 97% sequence conservation. fcabp-like genes are found in trypanosoma conorhini, trypanosoma freitasi, trypanosoma lewisi, herpetomonas megaseliae, leptomonas seymouri, and phytomonas serpens, but not in crithidia deanei, leishmania ...	1997	9225770
presentation via the class i pathway by leishmania amazonensis-infected macrophages of an endogenous leishmanial antigen to cd8+ t cells.	cd8+ t cells play a protective role in immunity to cutaneous leishmaniasis. however, it has been unclear how these cells execute this function, since results from several investigations attempting to demonstrate recognition of leishmania-infected macrophages by cd8+ t cells have been contradictory. in this study, we report the generation of cd8+ t cell lines specific for gp46/m-2, a leishmanial ag, previously shown to protectively immunize mice against a leishmania amazonensis challenge. using t ...	1997	9257846
immune response and protection in mice inoculated with leishmania amazonensis clones expressing different degrees of virulence.	the induction of protective immunity to leishmania amazonensis was investigated by injection of parasite clones of low and medium virulence into susceptible mice. to this end, l. amazonensis were cloned by limiting dilution and the clones' virulence was evaluated by the course of infection in susceptible mice. clones originally derived from the spleen showed virulence variations in comparison with that of the parental population (pp) of parasites. two low-virulence clones (sp 5 and sp 20) and on ...	1997	9272560
pore-forming proteins in pathogenic protozoan parasites.	pore-forming proteins (pfps) may play important roles in pathogenesis by protozoan parasites by either directly damaging the plasma membrane of the host cells or ensuring intracellular survival of the parasites by promoting their exit from lysosomal vacuoles. the leishmania amazonensis pore-forming cytolysin, leishporin, may play a crucial role in the pathogenesis of leishmaniasis.	1997	9294893
the potential effects of new synthetic drugs against leishmania amazonensis and trypanosoma cruzi.	amidine derivatives, never used before on trypanosomatids, were tested against leishmania amazonensis and trypanosoma cruzi. these drugs in doses up to 500 mg/kg inoculated into swiss mice did not show any toxic effect (santos, 1993). the in vitro effect of n,n'-diphenyl-4-r- benzamidine was evaluated. l. amazonensis promastigotes, epimastigotes and blood forms of t. cruzi, were assayed with/without the drugs in axenic media, using pentamidine isethionate and benznidazole, as reference drugs. th ...	1997	9301071
stage-independent splicing of transcripts two heterogeneous neighboring genes in leishmania amazonensis.	gene expression in trypanosomatid protozoa is largely regulated posttranscriptionally, e.g., 5' splice leader addition and 3' polyadenylation of mrnas. we examined these events in leishmania by mapping the splice sites of the transcripts from two different, but closely linked single-copy genes 2.3 kb apart. the coding regions of the approx. 1 kb upstream gene (p36) and the approx. 1.4 kb downstream gene (nagt) produce approx. 2 and 3 kb mrnas, respectively. both genes were overexpressed in cells ...	1997	9322740
experimental treatment of cutaneous leishmaniasis with argentilactone isolated from annona haematantha.	from the hexanic extract of roots of annona haematantha an alpha,beta-unsaturated delta-lactone was isolated and identified as argentilactone. this compound exhibited in vitro activity against various strains of leishmania ssp. at 10 micrograms/ml. balb/c mice infected with leishmania amazonensis were treated four weeks after infection with argentilactone by oral or subcutaneous routes for 14 days at 25 mg/kg daily. the reference drug, n-methylglucamine antimonate, was administered by subcutaneo ...	1997	9342948
experimental cutaneous leishmaniasis. iv. the humoral response of cebus apella (primates: cebidae) to infections of leishmania (leishmania) amazonensis, l. (viannia) lainsoni and l. (v.) braziliensis using the direct agglutination test.	the direct agglutination test (dat) was used to evaluate the serological response of 150 serum samples taken from 15 captive-bred capuchin monkeys cebus apella. these animals had been experimentally infected with either l. (leishmania) amazonensis, l. (viannia) lainsoni or l. (v.) braziliensis. monkeys infected with l. (l.) amazonensis or l. (v.) lainsoni were challenged with the homologous parasite one month after their spontaneous cure. dat antigens were prepared from l. (l.) donovani, l. (l.) ...	1997	9352003
leishmania braziliensis, molecular characterization of an elongation factor 1alpha gene.	the elongation factor ef-1alpha is one of the most studied components of the translation machinery owing to its abundance and possible role in other cellular functions. ef-1alpha mediates the correct coupling of the aminoacyl-trna on the a site of the ribosome in a gtp-dependent reaction. we have previously described an ef-1alpha dna sequence in leishmania amazonensis, plef11 (accession no. m92653), using pcr. in this paper we describe the dna sequence and genomic organization of l. braziliensis ...	1997	9370293
parasite-driven in vitro human lymphocyte cytotoxicity against autologous infected macrophages from mucosal leishmaniasis.	parasite-specific cytotoxicity in human leishmaniasis was evaluated in an autologous system. pbl from cutaneous leishmaniasis (cl) or mucosal leishmaniasis (ml) patients were exposed to leishmania amazonensis-infected autologous macrophages for 7 days and then used as effector cells in a cytotoxic assay using 51cr-labeled autologous infected macrophages as targets. results are reported as lu per 10(7) pbmc. cytotoxic activity is present in ml (9.7 +/- 2.1 lu/10(7) pbmc) but not in cl (1.5 +/- 2. ...	1997	9379046
in vitro maintenance of leishmania amastigotes directly from lesions: advantages and limitations.	leishmania amazonensis (mhom/br/77/ltb0016) amastigotes were obtained from mouse cutaneous lesions and maintained in vitro for 48 hr at ph 4.6, 33 c. these organisms were reproducing, capable of transformation to promastigotes, and did not display the promastigote-specific antigen, gp46. in contrast, 97% of the organisms maintained for 24 hr at 31 c, ph 7.3, were positive for gp46. thus, short-term cultivation of this l. amazonensis strain under appropriate conditions can provide a high yield of ...	1997	9379307
association of leishmania heat shock protein 83 antigen and immunoglobulin g4 antibody titers in brazilian patients with diffuse cutaneous leishmaniasis.	diffuse cutaneous leishmaniasis (dcl) is characterized by the presence of numerous nonulcerated nodules and plaques containing large numbers of leishmania amazonensis parasites and few lymphoid elements. the immune responses of dcl patients reflect severe antigen-specific t-cell deficiencies, while the antibody response to leishmania antigens is often accentuated. we report herein on the leishmania antigen-specific antibody subclass distribution in dcl patients and demonstrate that a dominant an ...	1997	9393843
immune responses induced by a leishmania (leishmania) amazonensis recombinant antigen in mice and lymphocytes from vaccinated subjects.	in the search for leishmania recombinant antigens that can be used as a vaccine against american cutaneous leishmaniasis, we identified a leishmania (leishmania) amazonensis recombinant protein of 33 kd (larp33) which is recognized by antibodies and peripheral blood leukocytes (pbl) from subjects vaccinated with leishvacin, larp33 was expressed in escherichia coli after cloning of a 2.2 kb sau3 digested genomic fragment of l. (l.) amazonensis into the pds56-6 his vector. immunoblotting analysis ...	1997	9394518
experimental cutaneous leishmaniasis: transmission electron microscopy of the inoculation site.	tissue response against inoculation of leishmania (leishmania) amazonensis promastigotes in the hind footpad was quite different between two strains of mice: in balb/c animals there was parasitism of perineurial cells by the 8th week post inoculation (wpi) and heavy parasitism of macrophages, as well as degenerated extracellular parasites close to collagen fibers at the 39th wpi, whereas in c57bi/6j mice there was heavy parasitism of macrophages at 6th wpi, dermal vessels with high endothelial c ...	1997	9203982
scavenger receptor-mediated delivery of antisense mini-exon phosphorothioate oligonucleotide to leishmania-infected macrophages. selective and efficient elimination of the parasite.	targeted delivery of a 17-mer antisense phosphorothioate oligodeoxyribonucleotide, complementary to the common 5'-end of every mrna of the parasite cells, to the phagolysosomes of cultured murine macrophages infected with leishmania mexicana amazonensis selectively and efficiently eliminated the parasite cells without causing any detectable harm to the host cells. the antisense mini-exon oligonucleotide (asm) was encapsulated into liposomes coated with maleylated bovine serum albumin (mbsa), the ...	1997	9065742
identification of a transcription factor like protein at the tor locus in leishmania mexicana amazonensis.	the tor gene (toxic nucleoside resistance gene) was mapped to a 2.3 kb fragment on the amplified dna from tubercidin resistant leishmania (tub). this dna fragment conferred upon wild type cells resistance to tubercidin, inosine dialdehyde, formycin a and b and allopurinol riboside and a reduced ability to accumulate purine nucleobases and nucleosides. these properties were characteristic of the parental tub cells which carried the intact amplified dna and have been hypothesized to be caused by a ...	1997	9476797
leishmania amazonensis promastigotes evade complement killing by interfering with the late steps of the cascade.	during their growth in vitro, promastigotes of leishmania amazonensis undergo differentiation from complement-susceptible to complement-resistant forms. here, we demonstrate that both forms bind comparable amounts of c3 on their surfaces, with the predominant molecule species being the haemolytically active c3b. likewise, equivalent amounts of c9 are deposited on both forms of promastigotes. however, while c9-bearing complexes are exposed on the cell surface of resistant promastigotes, they are ...	1997	9488871
cloning and functional analysis of the ribonucleotide reductase gene small subunit from hydroxyurea-resistant leishmania mexicana amazonensis.		1997	9497060
leishmania sp.: growth and survival are impaired by ion channel blockers.	in the present work we examined the effect of ion transport blockers on the growth and viability of leishmania sp. and on the infection of macrophages by the parasite. 4-aminopyridine and glibenclamide block voltage-dependent and k+ atp channels, respectively; amiloride is used to detect na+ channels and na+/h+ antiporters; and anthracene-9-carboxylic acid affects chloride channels. the ec50 for promastigote cultures of three strains of the leishmania subgenus, namely, leishmania (leishmania) nr ...	1998	9501844
leishmania amazonensis: the phagocytosis of amastigotes by macrophages.	in the present study, we examine the cell biology of leishmania amastigote uptake by mammalian cells and compare this process to the phagocytosis of igg-opsonized erythrocytes. we report that many aspects of amastigote uptake into macrophages resemble classical receptor-mediated phagocytosis. parasite uptake requires energy expenditure by macrophages but not by parasites. treating macrophages to prevent either energy metabolism or actin polymerization prevents amastigote uptake. the uptake of am ...	1998	9562419
leishmania amazonensis: long-term cultivation of axenic amastigotes is associated to metacyclogenesis of promastigotes.	axenic leishmania amazonensis cultures were obtained (with 2 years of follow-up) in schneider's medium at ph 5.5 and a temperature of 32 degrees c. differentiation of promastigotes into amastigotes is directly associated with the metacyclogenesis rate of the original promastigotes. promastigote cultures containing different percentages of metacyclic forms, as evaluated by the complement lysis test, resulted in axenic amastigote cultures containing a variable amount of undifferentiated forms. we ...	1998	9603489
partially glucose-capped oligosaccharides are found on the hemoglobins of the deep-sea tube worm riftia pachyptila.	we report here the structural determination of n-linked oligosaccharides found on extracellular hemoglobins of the hydrothermal vent tube worm riftia pachyptila. structures were elucidated by a combination of electrospray ionization tandem mass spectrometry, matrix-assisted laser desorption/ionization mass spectrometry, normal-phase high performance liquid chromatography, and exoglycosidase digestion. the sugar chains were found to consist mainly of high-mannose-type glycans with some structures ...	1998	9621107
leishmania (leishmania) amazonensis: purification and enzymatic characterization of a soluble serine oligopeptidase from promastigotes.	a soluble proteinase was purified 90-fold from extracts of promastigotes of leishmania (leishmania) amazonensis using a combination of ion-exchange chromatography in q-sepharose fast flow, gel filtration chromatography in sephacryl hr s-200, and chromatofocusing. the enzyme appeared as a single band with an apparent molecular weight of 101 kda by silver staining following sds-page, under both reducing and nonreducing conditions. the proteinase has a ph optimum between 8.0 and 8.5 and an isoelect ...	1998	9635438
genus-specific expression from the sl rna promoter of leishmania amazonensis.		1998	9635452
in vitro method for isolation of amastigote forms of leishmania amazonensis from j774g8 macrophage induced by temperature shifting.		1998	9698849
phase 1 study of an inactivated vaccine against american tegumentary leishmaniasis in normal volunteers in brazil.	a phase 1 double-blind placebo-controlled study was performed to evaluate a vaccine against american tegumentary leishmaniasis in 61 healthy male volunteers. side effects and the immune response to the vaccine were evaluated, with 1- and 2- dose schemes, with intervals of 7 or 21 days, each dose containing 1440 mg of protein n antigen of a single strain of leishmania amazonensis (ph8) diluted in merthiolated saline (1:10,000). merthiolated saline and an inert substance were used as placebos. no ...	1998	9698895
leishmania amazonensis infection is reduced in macrophages treated with guanine ribonucleosides.		1998	9707370
susceptibility and resistance to leishmania amazonensis in h-2q syngeneic high and low antibody responder mice (biozzi mice).	h-2 syngeneic h and l (biozzi) mice provide a model to study leishmania infections in which polar resistant and susceptible phenotypes are independent from h-2 differences. high-ab-responder (h) and low-ab-responder (l) mice syngeneic at the h-2 locus (h-2q) were, respectively, susceptible and highly resistant to leishmania amazonensis infection. l-mice resistance was associated with high ifn-gamma and transient il-4 production by lymph node (ln) cells, in contrast with sustained il-4 and decrea ...	1998	9716105
efficacies of ky62 against leishmania amazonensis and leishmania donovani in experimental murine cutaneous leishmaniasis and visceral leishmaniasis.	current therapy for leishmaniasis is unsatisfactory because parenteral antimonial salts and pentamidine are associated with significant toxicity and failure rates. we examined the efficacy of ky62, a new, water-soluble, polyene antifungal, against cutaneous infection with leishmania amazonensis and against visceral infection with leishmania donovani in susceptible balb/c mice. mice were infected with l. amazonensis promastigotes in the ear pinna and in the tail and were treated with ky62 or amph ...	1998	9756753
a new focus of cutaneous leishmaniasis due to leishmania amazonensis in a sub andean region of bolivia.	we detected a new outbreak focus with high incidence of cutaneous leishmaniasis in the sub andean region of la paz. this area was never considered previously as an endemic zone of leishmaniasis. leishmania stocks from human lesions were isolated: three stocks were explored by pulse field gradient electrophoresis, showing evidence for their affiliation to the l. mexicana complex. eight stocks were submitted to isoenzyme electrophoresis and compared with five reference strains: l. amazonensis, l. ...	1998	9821459
intracellular leishmania amazonensis killing induced by the guanine nucleoside 8-bromoguanosine.	in this study we investigated the effect of 8-bromoguanosine, an immunostimulatory compound, on the cytotoxicity of macrophages against leishmania amazonensis in an in vitro system. the results showed that macrophages treated with 8-bromoguanosine before or after infection are capable to reduce parasite load, as monitored by the number of amastigotes per macrophage and the percentage of infected cells (i.e. phagocytic index). since 8-bromoguanosine was not directly toxic to the promastigotes, it ...	1998	9876437
cloning and functional expression of the human glcnac-1-p transferase, the enzyme for the committed step of the dolichol cycle, by heterologous complementation in saccharomyces cerevisiae.	the gene for the human dolichol cycle glcnac-1-p transferase (alg7/gpt) was cloned by screening a human lung fibroblast cdna library. the library was constructed in a saccharomyces cerevisiae expression vector, and the positive clone was identified by complementation of the conditional lethal s.cerevisiae strain yph-a7-gal. this strain was constructed by replacing the endogenous promoter of the gpt-gene by the stringently regulated gal1-promoter. this construct allows to specifically suppress th ...	1998	9451016
in vivo formation of electron paramagnetic resonance-detectable nitric oxide and of nitrotyrosine is not impaired during murine leishmaniasis.	recent studies have provided evidence for a dual role of nitric oxide (no) during murine leishmaniasis. to explore this problem, we monitored the formation of no and its derived oxidants during the course of leishmania amazonensis infection in tissues of susceptible (balb/c) and relatively resistant (c57bl/6) mice. no production was detected directly by low-temperature electron paramagnetic resonance spectra of animal tissues. both mouse strains presented detectable levels of hemoglobin nitrosyl ...	1998	9453645
non-ulcerative cutaneous lesion in immunodeficient mice with leishmania amazonensis infection.	cutaneous leishmaniasis begins as papules or nodules at the site of promastigote inoculation. the next key pathogenic event in this disease is the formation of an ulcer at this site. leishmania infection in immunodeficient mice, however, showed non-ulcerative cutaneous lesions suggesting the involvement of the immune system in ulcer formation. severe combined immunodeficient (scid), recombination-activating gene 2 knockout (rag-2-/-), and immunocompetent mice were inoculated subcutaneously with ...	1999	11269325
characterization by pulse-field electrophoresis of a new region of dna amplification containing the m2 subunit of ribonucleotide reductase in hydroxyurea-resistant leishmania.	an extrachromosomal circular dna of of approximately 50-kb size was amplified in the hydroxyurea-resistant variant of leishmania mexicana amazonensis. the amplicon carried the m2 gene of ribonuleotide reductase as part of the gene encoding resistance to hydroxyurea. the amplicon was unstable. it disappeared rapidly as shown in pulse-field gradient electrophoresis gels after reversion of the cells for 20-80 days. this loss of amplified dna was accompanied by a rapid loss of resistance to hydroxyu ...	1999	9951961
purification, characterization, and drug susceptibility of tubulin from leishmania.	past work suggests that tubulin from kinetoplastid parasites may present an excellent drug target. to explore this possibility, tubulin was purified on a milligram scale from leishmania mexicana amazonensis promastigotes by sonication, deae-sepharose chromatography, and one cycle of assembly-disassembly. purified leishmanial tubulin is recognized by commercially available anti-tubulin antibodies and displays concentration dependent assembly in vitro. the vinca site agents vinblastine, maytansine ...	1999	10029309
putative reservoirs of leishmania amazonensis in a sub-andean focus of bolivia identified by kdna-polymerase chain reaction.		1999	10029903
structural and functional analysis of the lamdr1 multidrug resistance gene in leishmania amazonensis.	we determined primary sequences of the lamdr1 gene in leishmania amazonensis, a protozoan parasite that causes cutaneous leishmaniasis. the longest open reading frame encodes 1341 amino acids for a protein consisting of two similar halves, each containing six putative transmembrane domains and one atp-binding domain. the protein has no potential n-glycosylation sites at the extracellular region. the lamdr1 protein was 91 and 78% identical to the closely related ldmdr1 in l. donovani and lemdr1 i ...	1999	10049701
antisense oligonucleotides containing modified bases inhibit in vitro translation of leishmania amazonensis mrnas by invading the mini-exon hairpin.	complementary oligodeoxynucleotides (odns) that contain 2-aminoadenine and 2-thiothymine interact weakly with each other but form stable hybrids with unmodified complements. these selectively binding complementary (sbc) agents can invade duplex dna and hybridize to each strand (kutyavin, i. v., rhinehart, r. l., lukhtanov, e. a., gorn, v. v., meyer, r. b., and gamper, h. b. (1996) biochemistry 35, 11170-11176). antisense odns with similar properties should be less encumbered by rna secondary str ...	1999	10075723
status of respiration and atp content in arsenite resistant leishmania mexicana amazonensis.	cellular atp and rate of respiration are important for the cell survival. we have analyzed both the parameters in wild type and arsenite resistant leishmania mexicana amazonensis. there was no significant change observed in the rate of respiration and cellular atp content between drug resistant cells (resistance to 30 microm of sodium arsenite) and wild type cells. further, we have tested the effect of higher concentrations (i.e. 100 microm and 500 microm) of sodium arsenite on the atp content o ...	1999	10089157
evaluation of the stability and immunogenicity of autoclaved and nonautoclaved preparations of a vaccine against american tegumentary leishmaniasis.	this study was designed to evaluate the immunogenicity of autoclaved and nonautoclaved preparations of a vaccine composed of whole antigens from killed promastigotes of leishmania amazonensis. leishmanin skin-test (lst)-negative volunteers were immunized with either autoclaved or nonautoclaved vaccine preparations (32 and 36 subjects, respectively) that had been maintained at 4 degrees c for one year before the onset of this trial. immunological tests were performed two days before and 40 days a ...	1999	10195630
roles of free gpis in amastigotes of leishmania.	glycosylated phosphatidylinositols (gpis) are abundant cell surface molecules of the leishmania. amastigote-specific gpis amgpi-y and amgpi-z, both ethanolamine (etn)-containing glycolipids, were identified in leishmania amazonensis. a paucity of gpi-anchored proteins in amastigotes of l. amazonensis made the kinetoplastid suitable for evaluating the importance of free (i.e. unconjugated to protein or polysaccharide) gpis. a strain deficient in both amgpi-y and amgpi-z was produced by stable tra ...	1999	10215028
successful topical treatment of murine cutaneous leishmaniasis with a combination of paromomycin (aminosidine) and gentamicin.	cutaneous leishmaniasis is presently treated with 20 days of parenteral therapy with a frequently toxic drug (antimony). topical formulations of paromomycin (15%) plus methylbenzethonium chloride (mbcl, 12%) or plus urea (10%) in soft white paraffin have been tested for old and new world disease in humans. we compared the efficacy of a new topical formulation, wr 279,396 (paromomycin [15%] plus gentamicin [0.5%]) to the clinical formulations in the treatment of cutaneous disease in balb/c mice. ...	1999	10219319
selective effect of 2',6'-dihydroxy-4'-methoxychalcone isolated from piper aduncum on leishmania amazonensis.	2',6'-dihydroxy-4'-methoxychalcone (dmc) was purified from the dichloromethane extract of piper aduncum inflorescences. dmc showed significant activity in vitro against promastigotes and intracellular amastigotes of leishmania amazonensis, with 50% effective doses of 0.5 and 24 micrograms/ml, respectively. its inhibitory effect on amastigotes is apparently a direct effect on the parasites and is not due to activation of the nitrogen oxidative metabolism of macrophages, since the production of ni ...	1999	10223942
experimental treatment with sodium stibogluconate of hamsters infected with leishmania (leishmania) chagasi and leishmania (leishmania) amazonensis.	the present paper reports the experimental treatment of hamsters infected with leishmania chagasi and leishmania amazonensis with sodium stibogluconate (20 mg/kg/day x 20 days). only with l. chagasi did the treatment result in the complete elimination of parasites from the spleen. however, no parasitological cure was achieved in hamsters infected with l. amazonensis.	1999	10228371
leishmania (viannia) panamensis/leishmania (leishmania) amazonensis--a warning.		1999	10234193
the role of natural killer cells in the early period of infection in murine cutaneous leishmaniasis.	in order to study the role of natural killer (nk) cells during the early period of leishmania infection, balb/c mice were selectively and permanently depleted of nk cells by injection with 90sr and subsequently infected with leishmania (leishmania) amazonensis (hsjd-1 strain). 90sr is known to selectively deplete nk cells, leaving an intact t- and b-cell compartment and preserving the ability to produce both interferon alpha and il-2. this method of depletion has advantages when compared with de ...	1999	10347791
leishmania amazonensis infection in nude mice.	leishmania amazonensis is an intracellular protozoan parasite of macrophages. cutaneous leishmaniasis in an immunocompetent host begins as papules or nodules followed by ulceration at the site of promastigote inoculation. in this study, the pathological changes of cutaneous leishmaniasis lesions in t cell deficient nude mice were examined. when infected with l. amazonensis promastigotes, nude mice developed non-ulcerative cutaneous nodules. by histological examination of cutaneous lesions, massi ...	1999	10374074
effect of acidic ph on heat shock gene expression in leishmania.	temperature and ph shifts trigger differential gene expression and stage transformation in leishmania. the parasites encounter dramatic fluctuations in the extra-cellular ph between the mid-gut of the sand fly (ph>8) and the phagolysosomal vacuole of mammalian macrophages (ph<6). the authors examined the effect of ph shifts on heat shock gene expression in leishmania amazonensis and leishmania donovani promastigotes. acidic ph resulted in preferential stability of the hsp83 transcripts at 26 deg ...	1999	10376997
improvement of in vitro and in vivo antileishmanial activities of 2', 6'-dihydroxy-4'-methoxychalcone by entrapment in poly(d,l-lactide) nanoparticles.	the inhibition of intracellular leishmania amazonensis growth by 2', 6'-dihydroxy-4'-methoxychalcone (dmc) isolated from piper aduncum was further enhanced after encapsulation of dmc in polymeric nanoparticles. encapsulated dmc also showed increased antileishmanial activity in infected balb/c mice, as evidenced by significantly smaller lesions and fewer parasites in the lesions.	1999	10390243
h-2m molecules, like mhc class ii molecules, are targeted to parasitophorous vacuoles of leishmania-infected macrophages and internalized by amastigotes of l. amazonensis and l. mexicana.	in their amastigote stage, leishmania are obligatory intracellular parasites of mammalian macrophages, residing and multiplying within phagolysosomal compartments called parasitophorous vacuoles (pv). these organelles have properties similar to those described for the mhc class ii compartments of antigen-presenting cells, sites where peptide-class ii molecule complexes are formed before their expression at the cell surface. after infection with leishmania amazonensis or l. mexicana, endocytosis ...	1999	10393812
systemic delivery of an adenovirus expressing ebv-derived vil-10 in mice infected with schistosoma mansoni or leishmania amazonensis: controversial effects on the development of pathological parameters.	within the context of microorganism/host interactions, those which last over weeks are expected to be sensitive to more or less sustained and targeted immuno-intervention, such as delivery of cytokines known to operate as down-regulators of acute inflammatory processes. il-10 has received growing attention as a potential tool in immunotherapy, due to its anti-inflammatory and immunosuppressive properties. therefore, using two experimental models of long-term interactions between parasites and la ...	1999	10400822
the anti-leishmanial effect of kalanchoe is mediated by nitric oxide intermediates.	we have previously shown that oral treatment with the leaf extract of the plant kalanchoe pinnata (kp) significantly decreases the lesion size and the parasite load in balb/c mice infected with leishmania amazonensis. here we report on the mode of action of kp, particularly on the induction of nitric oxide (no) production by macrophages. we observed that kp has no direct inhibitory activity on extracellular promastigotes, but effectively decreases the intracellular amastigote growth in a dose-re ...	1999	10406036
leishmania amazonensis infection induces changes in the electrophysiological properties of macrophage-like cells.	whole cell patch-clamp recordings were used to study the electrical properties of the macrophage-like cell line j774.1, after infection with leishmania amazonensis. infection induced a significant increase in cell size and membrane capacitance, suggesting that parasite invasion leads to the addition of plasma membrane to the host cell. by 24 hr after infection, the host cell membrane potential was significantly more hyperpolarized than control cells, and this difference remained for the subseque ...	1999	10430661
comparison of different staining procedures for the flow cytometric analysis of u-937 cells infected with different leishmania-species.	the human macrophage cell line u-937 infected with different leishmania species, leishmania mexicana amazonensis (lma), leishmania donovani (ld) and leishmania infantum (li), was analyzed by flow cytometry (fcm). leishmania spp. were labeled with different stains prior to the infection of the u-937 cells (bcecf-am, pkh2-gl and syto 17) or after the infection (ao, fitc-conjugated monoclonal antibodies, pi). infected cells were analyzed by flow cytometry, fluorescence microscopy and in parallel mi ...	1999	10445312
a dhfr-ts- leishmania major knockout mutant cross-protects against leishmania amazonensis.	e10-5a3 is a dhfr-ts- leishmania major double knockout auxotrophic shown previously to induce substantial protection against virulent l. major infection in both genetically susceptible and resistant mice. we investigated the capacity of dhfr-ts- to protect against heterologous infection by l. amazonensis. the degree of protection was evaluated by immunization of balb/c or c57bl/6 mice with e10-5a3, followed by l. amazonensis challenge. whether immunized by subcutaneous (sc) or intravenous (iv) i ...	1999	10446007
short report: evaluation of the potency and stability of a candidate vaccine against american cutaneous leishmaniasis.	availability of a safe, immunogenic, and affordable vaccine would represent the best strategy for control of cutaneous leishmaniasis (cl). stability in field conditions is a essential property for any candidate vaccine. the stability and immunogenicity of three different preparations (thimerosal-preserved, autoclaved, and lyophilized) of a killed leishmania amazonensis vaccine were assessed using fresh products and after 12 months of storage at 4 degrees c. autoclaving was associated with a time ...	1999	10463682
antisense effects of oligonucleotides complementary to the hairpin of the leishmania mini-exon rna.	we investigated the binding and the translation inhibitory properties of hexadecamers complementary to the mini-exon sequence of the protozoan parasite leishmania amazonensis. this targeted rna region folds into a hairpin. large differences were observed in the antisense properties of the different oligomers although their binding to rna always requires the disruption of the stem region.	1999	10474250
altered tyrosine phosphorylation of erk1 map kinase and other macrophage molecules caused by leishmania amastigotes.	the involvement of tyrosine phosphorylation during macrophage infection with leishmania amazonensis amastigotes was investigated. ptk antagonists such as genistein, herbimycin a, geldanamycin and tyrphostin 25 had no significant effect on adhesion to, or entry into, murine peritoneal macrophages, but increased parasite intracellular survival. lps-induced tyrosine phosphorylation of target host proteins assessed by immunoprecipitation and western blot was impaired or reversed by living amastigote ...	1999	10477171
construction of chimeric phagosomes that shelter mycobacterium avium and coxiella burnetii (phase ii) in doubly infected mouse macrophages: an ultrastructural study.	dual infection of cells may divert pathogens to intracellular compartments different from those occupied in mono-infected cells. in the present studies, mouse bone marrow in vitro-derived macrophages were first infected with virulent mycobacterium avium, which are normally singly lodged within tight phagosomes. these phagosomes do not mature; they undergo homotypic fusion with early endosomes and do not fuse with lysosomes. seven days later, the cultures were superinfected with phase ii (non-vir ...	1999	10494865
expression and cellular localization of ribonucleotide reductase small subunit m2 protein in hydroxyurea-resistant leishmania mexicana amazonensis.	we raised a specific antiserum against the recombinant m2 subunit protein of ribonucleotide reductase of leishmania mexicana amazonensis in rabbit. this antiserum was used to study the expression and cellular location of the m2 protein in wildtype as well as hydroxyurea-resistant variants (hur) of the parasite. the protein increased with increasing dose of the drug used for selection of resistance. the increase in protein level was accompanied by an increase in the copy numbers of mrna of the m2 ...	1999	10498182
protective immunity using recombinant human il-12 and alum as adjuvants in a primate model of cutaneous leishmaniasis.	protection from cutaneous leishmaniasis, a chronic ulcerating skin lesion affecting millions, has been achieved historically using live virulent preparations of the parasite. killed or recombinant ags that could be safer as vaccines generally require an adjuvant for induction of a strong th1 response in murine models. murine ril-12 as an adjuvant with soluble leishmania ag has been shown to protect susceptible mice. we used 48 rhesus macaques to assess the safety, immunogenicity, and efficacy of ...	1999	10510390
persistence of leishmania antigen in c57bl/6j inbred mice infected with leishmania (leishmania) amazonensis.	to develop an animal model for studying mucocutaneous leishmaniasis.	1999	10513053
protection of c57bl/10 mice by vaccination with association of purified proteins from leishmania (leishmania) amazonensis.	in the past few years, induction of protective immunity to cutaneous leishmaniasis has been attempted by many researchers using a variety of antigenic preparations, such as living promastigotes or promastigote extracts, partially purified, or defined proteins. in this study, eleven proteins from leishmania (leishmania) amazonensis (lla) with estimated molecular mass ranging from 97 to 13.5kda were isolated by polyacrylamide gel electrophoresis and electro-elution. the proteins were associated as ...	1999	10564919
efficacy of the triazole sch 56592 against leishmania amazonensis and leishmania donovani in experimental murine cutaneous and visceral leishmaniases.	current therapy for leishmaniasis is unsatisfactory. efficacious and safe oral therapy would be ideal. we examined the efficacy of sch 56592, an investigational triazole antifungal agent, against cutaneous infection with leishmania amazonensis and visceral infection with leishmania donovani in balb/c mice. mice were infected in the ear pinna and tail with l. amazonensis promastigotes and were treated with oral sch 56592 or intraperitoneal amphotericin b for 21 days. at doses of 60 and 30 mg/kg/d ...	1999	10582881
studies on the effectiveness of diarylheptanoids derivatives against leishmania amazonensis.	in a previous work we demonstrated that diarylheptanoids extracted from centrolobium sclerophyllum are very active against leishmania amazonensis promastigotes. in order to continue our studies with these class of compounds, we decided to evaluate the activity of several diarylheptanoids derived from curcumin (diferuloyl methane) against the extracellular form (promastigotes) of l. amazonensis. furthermore, an experiment against the intracellular form of the parasite (amastigotes) was carried ou ...	1999	10585657
lutzomyia nuneztovari anglesi (le pont & desjeux, 1984) as a vector of leishmania amazonensis in a sub-andean leishmaniasis focus of bolivia.	recently, a new leishmania amazonensis focus was described in a sub-andean region (1,450-2,100 meters above sea level) of bolivia. in this area, three anthropophilic sandfly species were identified: lutzomyia nuneztovari anglesi le pont & desjeux, 1984, which represented 86-99% of the captures, lu. galatiae le pont et al., 1998, and lu. shannoni dyar 1929. only lu. nuneztovari anglesi was found naturally infected by flagellates (16 of 1,715 females). three leishmania stocks were isolated and ana ...	1999	10586923
impairment of sterol biosynthesis leads to phosphorus and calcium accumulation in leishmania acidocalcisomes.	the induction of the formation of inclusion vesicles in leishmania amazonensis by the sterol biosynthesis inhibitors (sbi) ketoconazole and terbinafine has been reported previously. these compartments were recently identified as acidocalcisomes. by the use of electron spectroscopic imaging and energy loss spectroscopy, the presence of calcium, phosphorus and oxygen in the electron-dense inclusions located within the acidocalcisomes has been demonstrated. endoplasmic reticulum cisternae formed me ...	1999	10589730
episomal expression of specific sense and antisense mrnas in leishmania amazonensis: modulation of gp63 level in promastigotes and their infection of macrophages in vitro.	the major surface glycoprotein (gp63) of leishmania amazonensis is a metalloprotease implicated in the infection of mammalian macrophages. the expression of gp63 and its participation in this infection were further examined by modulating the level of this molecule in a virulent gp63-abundant wild-type clone. promastigotes were transfected with gp63 genes cloned into a leishmania-specific vector in two different orientations, leading to the expression of gp63 sense and antisense rnas. with increa ...	2000	10603371
characterization of leishmania sp. strains isolated from autochthonous cases of human cutaneous leishmaniasis in santa catarina state, southern brazil.	four leishmania sp. samples were isolated from autochthonous human cases of american cutaneous leishmaniasis (acl) in santa catarina state, southern brazil. these strains were characterized using indirect immunofluorescence with a panel of leishmania-specific monoclonal antibodies (mabs), and by pcr amplification and hybridization assay of the mini-exon gene with group specific probes. the results obtained with the mabs were in agreement with the genetic marker. two isolates (mhom/br/89/jsc89-h1 ...	2000	10643912
immunotherapy with live bcg plus heat killed leishmania induces a t helper 1-like response in american cutaneous leishmaniasis patients.	previous work has shown that american cutaneous leishmaniasis (acl) patients treated with viable bcg plus heat killed promastigotes of leishmania amazonensis show the same rate of cure as patients receiving conventional chemotherapy. the treatment is safe and economical, but the immunological correlates of cure have not been examined. in the present study, t cell responses have been analysed in 43 acl patients, including patient groups sampled before and after therapy, and in 10 endemic controls ...	2000	10652119
immunoassays for pentamidine and related compounds: development of a facile inhibitory elisa suitable for clinical use.	aromatic dicationic drugs have a broad spectrum of activity against protozoal and fungal pathogens including pneumocystis carinii, leishmania mexicana amazonensis, cryptosporidium parvum and cryptococcus neoformans. pentamidine serves as the exemplar for an extensive collection of newly synthesized related compounds, which have reduced toxicity and a wider range of target organisms. assays of pentamidine and related compounds have depended on hplc-tandem mass spectrometry (hplc-tms) for the quan ...	2000	10683618
leishmania amazonensis infection does not inhibit systemic nitric oxide levels elicited by lipopolysaccharide in vivo.	leishmaniasis is a parasitic disease that leads to chronic inflammation. macrophages, depending on their activation state, are either hosts or killers of the parasites. downregulation of nitric oxide (no) synthesis by the parasite infecting the macrophages has been proposed to be an important evading mechanism based on in vitro studies. we confirmed inhibition of no release by macrophages infected with leishmania amazonensis in vitro. to examine the role of the parasite in regulating no producti ...	2000	10701568
purification, cloning, and characterization of an acidic ectoprotein phosphatase differentially expressed in the infectious bloodstream form of trypanosoma brucei.	we purified an ecto-phosphatase of 115 kda (tryacp115) specifically expressed by bloodstream forms of trypanosoma brucei. the corresponding gene coded for a 45-kda protein potentially including a signal peptide, a membrane-spanning domain and an n-terminal domain containing 8 n-glycosylation sites. there was no significant sequence homology with other phosphatases. antiserum to the escherichia coli recombinant n-terminal domain, petase7, recognized a protein of 55 kda in western blots after degl ...	2000	10722732
redistribution of plasma-membrane surface molecules during formation of the leishmania amazonensis-containing parasitophorous vacuole.	leishmania amazonensis presents two developmental stages that gain access to the host macrophage through phagocytosis. the protozoan resides in a membrane-bound compartment, the parasitophorous vacuole (pv), which can fuse with the endocytic system. for evaluation of the parasite/host-cell interaction process and of pv biogenesis, the two parasite forms or host-cell membrane whose surface had previously been labeled with specific probes for lipids, proteins, and sialoglycoconjugates were allowed ...	2000	10726992
internalization of leishmania mexicana complex amastigotes via the fc receptor is required to sustain infection in murine cutaneous leishmaniasis.	we show here that maintenance of leishmania infections with leishmania mexicana complex parasites (leishmania amazonensis and leishmania pifanoi) is impaired in the absence of circulating antibody. in these studies, we used mice genetically altered to contain no circulating antibody, with and without functional b cells. this experimental design allowed us to rule out a critical role for b cell antigen presentation in leishmania pathogenesis. in addition, we show that mice lacking the common gamm ...	2000	10727468
detection of cysteine-proteinases in leishmania amazonensis promastigotes using a cross-reactive antiserum.	rabbit serum against the cysteine-proteinases papain has been employed for the cellular localization of cysteine-proteinases of in leishmania amazonensis promastigotes. by immunocytochemistry, immune complexes were found in the plasma membrane and in the flagella pocket of the parasite. the antiserum immunoprecipitated major iodinated proteins with molecular masses of 66, 45, 28 and 24 kda and a wide partitioning of the triton x-114 detergent phase. the presence of cysteine-proteinase at the cel ...	2000	10802182
synthesis of high-mannose type neoglycolipids: active targeting of liposomes to macrophages in gene therapy.	the concise synthesis of five biantennary oligomannose neoglycolipids is presented. employing a strategy based on the principles of reactivity tuning and orthogonal activation, the oligomannose moieties, isolated from the glycoprotein 63 of the parasite leishmania mexicana amazonensis, were rapidly assembled taking advantage of common structural motifs found in these n-glycans. deprotection of all structures was achieved in high yield by hydrogenolysis. the deprotected glycoconjugates were subse ...	2000	10840965
il-4-independent inhibition of il-12 responsiveness during leishmania amazonensis infection.	leishmania amazonensis induces a nonhealing infection in c3h mice, whereas infection with leishmania major is self-healing. we found that c3h mice infected with l. amazonensis exhibited decreased il-12 production, which could account for the susceptibility to this organism. however, exogenous il-12 administration failed to induce a healing immune response. the failure of l. amazonensis-infected c3h mice to respond to il-12 was associated with a specific defect in il-12 receptor beta2 (il-12rbeta ...	2000	10861073
cd4(+) cells are indispensable for ulcer development in murine cutaneous leishmaniasis.	one of the most characteristic clinical features in cutaneous leishmaniasis is the development of nodules followed by ulcerations at the site of infection. leishmania amazonensis-infected mice show similar ulcerative lesions. leishmania-infected severe combined immunodeficiency (scid) mice, however, have been shown to develop nonulcerative nodules. in the present study, the roles of t cells in ulceration were examined using scid mice in cell reconstitution experiments. after development of nonul ...	2000	10899857
macrophage damage by leishmania amazonensis cytolysin: evidence of pore formation on cell membrane.	we have previously shown that both promastigotes and amastigotes of leishmania amazonensis contain a lytic protein that damages erythrocytes and nucleated cells, including macrophages (f. s. m. noronha, f. j. ramalho-pinto, and m. f. horta, infect. immun. 64:3975-3982, 1996). using the patch-clamp technique, we show here that cell damage by parasite extracts is mediated by the formation of nonselective pores on the target membrane. this demonstrates that l. amazonensis cytolysin is a pore-formin ...	2000	10899858
action of pentoxifylline on experimental cutaneous leishmaniasis due to leishmania (leishmania) amazonensis.	in the animal model of leishmaniasis caused by leishmania (leishmania) amazonensis there is a complex mechanism of the host-parasite interaction. the present study was performed to interfere with the inflammatory reaction to the parasites, through immune modulation. female c5bl/6 isogenic mice were used, some of which were inoculated on the right ear and others on the right footpad with 3.10(6) stationary phase promastigotes of the mhom/br/ph8 strain of l. (l.) amazonensis, and were allocated in ...	2000	10904402
therapeutic trial in experimental tegumentary leishmaniasis caused by leishmania (leishmania) amazonensis. a comparative study between mefloquine and aminosidine.	one hundred and eighty-two male inbred c57/bl/6 mice were infected with 3 x 10(6) leishmania (leishmania) amazonensis promastigotes of the mhom/br/ph8 strain by means of a subcutaneous injection in the right ear. the animals were separated in three groups: 1) oral mefloquine hydrochloride treatment (16 mg/kg/day/10 days), 2) intramuscular aminosidine (paromomycin) treatment (20 mg/kg/20 days) and 3) control. twenty-six mice of each treated group were sacrificed, one at the end of treatment (nine ...	2000	10936952
isolation and characterization of gomesin, an 18-residue cysteine-rich defense peptide from the spider acanthoscurria gomesiana hemocytes with sequence similarities to horseshoe crab antimicrobial peptides of the tachyplesin family.	we have purified a small size antimicrobial peptide, named gomesin, from the hemocytes of the unchallenged tarantula spider acanthoscurria gomesiana. gomesin has a molecular mass of 2270.4 da, with 18 amino acids, including a pyroglutamic acid as the n terminus, a c-terminal arginine alpha-amide, and four cysteine residues forming two disulfide bridges. this peptide shows marked sequence similarities to antimicrobial peptides from other arthropods such as tachyplesin and polyphemusin from horses ...	2000	10942757
insulin-like growth factor (igf)-i affects parasite growth and host cell migration in experimental cutaneous leishmaniasis.	while the control or progression of leishmaniasis depends on host immune responses, the initial inflammatory process represents a key event. this process involves the participation of several cytokines and growth factors induced during inflammation as well as factors already present at the site of infection such as insulin-like growth factor (igf)-i. we have previously demonstrated a potential role for igf-i in experimental cutaneous leishmaniasis based on the significant increase in lesion size ...	2000	10971746
essential role of platelet-activating factor in control of leishmania (leishmania) amazonensis infection.	in the present study we investigated the role of platelet-activating factor (paf) and prostaglandins in experimental leishmania (leishmania) amazonensis infection and the relationship between these mediators and nitric oxide (no) production. mouse peritoneal macrophages elicited with thioglicolate were infected with leishmania amastigotes, and the infection index determined 48 h later. the course of infection was monitored for 5 weeks in mice infected in the footpad with promastigotes by measuri ...	2000	11035745
effect of amidine derivatives on leishmania amazonensis axenic amastigotes. preliminary studies of structure-activity relationships	in a previous work, searching for new drugs with high efficiency and low toxicity, the in vitro antileishmanial activity of a series of seven amidine derivatives against leishmania amazonensis promastigotes was reported. in order to compare the potential difference in the susceptibility between the two developmental stages of the parasite to these compounds, an analysis of the effects of these amidine derivatives on promastigotes and axenically grown amastigotes of l. amazonensis was carried out ...	2000	11105235
a sensitive method for assaying chemotaxic responses of leishmania promastigotes.	this article describes a sensitive, cheap, and easy method for assaying chemotaxic responses of leishmania promastigotes. a gradient of the substance to be assayed was produced inside a series of commercially available capillary tubes submerged in a promastigote suspension. after an incubation period, the attractiveness of the substance under test was measured by counting the number of parasites in the capillaries in a neubauer chamber. different responses were detected in two strains of leishma ...	2000	11162370
proteolytic activation of leishporin: evidence that leishmania amazonensis and leishmania guyanensis have distinct inactive forms.	crude extracts of leishmania amazonensis, but not of l. guyanensis, are lytic to erythrocytes and nucleated cells, including macrophages. l. amazonensis-mediated lysis is caused by a membrane-associated pore-forming protein, named a-leishporin. here we show that l. amazonensis, but not l. guyanensis, promastigote extracts increase their hemolytic activity when kept at 4 degrees c for a few days or at 37 degrees c for a few hours. we show that the activation in the extracts is mediated by a cytos ...	2000	11163443
different leishmania species determine distinct profiles of immune and histopathological responses in cba mice.	most experimental studies on leishmaniasis compare two different inbred strains of mice that are resistant or susceptible to one species of leishmania. in the present study we characterized some cytokines and nitric oxide production as well as histological changes related to resistance and susceptibility in isogenic cba mice infected with leishmania major or leishmania amazonensis. cba mice are capable of controlling infection with l. major, but they succumb to infection with l. amazonensis. cel ...	2000	11165924
safety and immunogenicity of a killed leishmania (l.) amazonensis vaccine against cutaneous leishmaniasis in colombia: a randomized controlled trial.	the safety and immunogenicity of an intramuscular (i.m.) and intradermal (id) formulation of autoclaved leishmania (leishmania) amazonensis vaccine was evaluated in 296 volunteers in a randomized, placebo-controlled, double-blind trial in colombia. there were 4 vaccination groups: i.m. vaccine, i.m. placebo, id vaccine, and id placebo. the id formulations were mixed with bcg as adjuvant at the time of injection. for each group, 3 vaccinations were given with a 20-day interval between injections, ...	2000	11198661
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
megasome biogenesis in leishmania amazonensis: a morphometric and cytochemical study.	megasomes are large lysosomes found in the amastigote stage of leishmania species belonging to the mexicana complex. the biogenesis of megasomes was investigated by transmission electron microscopy during the transformation of promastigotes into the amastigote form of l. amazonensis maintained in axenic cultures. mainly small vacuoles with low electron density were found in the promastigote and early intermediate forms. morphometrical analysis showed an increase in the volume density of these st ...	2001	11206117
molecular, cellular and functional characterizations of a novel icam-like molecule of the immunoglobulin superfamily from leishmania mexicana amazonensis.	a molecule with two immunoglobulin (ig) domains cloned from leishmania mexicana amazonensis was characterized to have a sequence homology to the ig domains of an icam-like molecule telencephalin, cloned from the brain of mammals, as well as to the variable domains of human immunoglobulin lambda light chain. the molecule therefore appears to be an icam-like molecule as well as a member of the immunoglobulin superfamily. we thus named it icam-l for leishmania icam. the gene was coamplified with th ...	2001	11223133
increased efficacy of antileishmanial antisense phosphorothioate oligonucleotides in leishmania amazonensis overexpressing ribonuclease h.	ribonuclease h (rnase h), an enzyme that cleaves an rna sequence base-paired with a complementary dna sequence, is proposed to be the mediator of antisense phosphorothioate oligonucleotide (s-oligo) lethality in a cell. to understand the role of rnase h in the killing of the parasitic protozoan leishmania by antisense s-oligos, we expressed an episomal copy of the trypanosoma brucei rnase h1 gene inside l. amazonensis promastigotes and amastigotes that constitutively express firefly luciferase. ...	2001	11226381
leishmanicidal activity of stearylamine-bearing liposomes in vitro.	liposomes consisting of stearylamine (sa) and egg yolk phosphatidylcholine (pc) were studied for their cytotoxic activity against freshly transformed promastigotes and intracellular amastigotes of leishmania donovani, the causative agent of visceral leishmaniasis. more than 99% of the parasites of strain ag83 were killed within 60 min by treatment with 22 mol% sa-pc liposomes (132 microg/ml total lipids). this was further confirmed by incubating the liposome-treated promastigotes at 22 c for 96 ...	2001	11227889
kinetics of the intracellular differentiation of leishmania amazonensis and internalization of host mhc molecules by the intermediate parasite stages.	the establishment of leishmania in mammals depends on the transformation of metacyclic promastigotes into amastigotes within macrophages. the kinetics of this process was examined using mouse macrophages infected with metacyclic promastigotes of l. amazonensis. the appearance of amastigote characteristics, including large lysosome-like organelles called megasomes, stage-specific antigens, high cysteine protease activity and sensitivity to l-leucine methyl ester, was followed over a 5-day period. ...	2001	11289063