Publications
| Title | Abstract | Year Filter | PMID(sorted descending) Filter |
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| a microplate assay for leishmania amazonensis promastigotes expressing multimeric green fluorescent protein. | convenient and economical assays capable of screening many compounds are vital to advance the development of drug therapy. this is particularly important for many of the infections that occur mainly in the third world. the development of such a spectrofluorometric assay for the protozoan parasite leishmania is presented here. using multimeric (four monomers) green fluorescent protein (gfp), leishmania amazonensis promastigotes were generated with brightness measurable in 96-well microtiter plate ... | 2003 | 12632163 |
| effect of amidine derivatives on nitric oxide production by leishmania amazonensis promastigotes and axenic amastigotes. | the effects of pentamidine isethionate (reference drug) and n,n'-diphenyl-4-methoxy-benzamidine (test compound) on no. production by leishmania amazonensis promastigotes and axenic amastigotes were investigated by measuring nitrite, a by-product of nitric oxide released into culture supernatants. the no. production by infective promastigotes was inhibited by och(3)-amidine in about 23.53% and by pentamidine in only 3.78%. in axenic amastigotes, the inhibition of no. production by och(3)-amidine ... | 2003 | 12586535 |
| new pcr assay using glucose-6-phosphate dehydrogenase for identification of leishmania species. | glucose-6-phosphate dehydrogenase (g6pd) is one of the multilocus enzymes used to identify leishmania by zymodeme analysis. the polymorphic pattern revealed by partial characterization of the gene encoding g6pd generated molecular markers useful in the identification of different leishmania species by pcr. initially degenerate oligonucleotides were designed on the basis of data on the conserved active center described for other organisms. primers for reverse transcription-pcr experiments, design ... | 2003 | 12574243 |
| effect of hydroxyurea on the intracellular multiplication of toxoplasma gondii, leishmania amazonensis and trypanosoma cruzi. | toxoplasma gondii, leishmania amazonensis and trypanosoma cruzi are obligate intracellular parasites that multiply until lysis of host cells. the present study was undertaken to evaluate the effect of hydroxyurea (an inhibitor of cell division at the g1/s phase) on the multiplication of l. amazonensis, t. gondii, and t. cruzi in infected host cells. infected cells were treated with hydroxyurea (4 mm) for 48 h. hydroxyurea arrested intracellular multiplication of all infective forms of the parasi ... | 2003 | 12532228 |
| influence of vertebrate blood meals on the development of leishmania (viannia) braziliensis and leishmania (leishmania) amazonensis in the sand fly lutzomyia migonei (diptera: psychodidae). | the effect of blood meals from humans and seven domestic, wild, or laboratory animals (dogs, horses, chickens, rats, opossums, mice, and hamsters) on the development of leishmania braziliensis and l. amazonensis was studied in the sand fly lutzomyia migonei. the development of l. braziliensis and l. amazonensis exhibited peripylarian and suprapylarian patterns of development, respectively, in the sand fly gut with all blood meals tested. the blood meal sources influenced the infection rate of th ... | 2002 | 12518856 |
| biochemical analysis of proteins and lipids found in parasitophorous vacuoles containing leishmania amazonensis. | one fundamental step of leishmania-macrophage interaction is the phase of parasite internalization through an endocytic process, with the formation of the parasitophorous vacuole (pv). the present study analyzed this process using two approaches. first, to investigate the host cell proteins which take part in this compartment, the macrophage surface was biotinilated and allowed to interact with both leishmania forms, the pv was then isolated, and the biotinilated proteins were analyzed by wester ... | 2003 | 12489012 |
| co-infection by leishmania amazonensis and l. infantum/l. chagasi in a case of diffuse cutaneous leishmaniasis in bolivia. | we present the first report of a co-infection by leishmania amazonensis and l. infantum/l. chagasi isolated in 1993 from a patient with diffuse cutaneous leishmaniasis (dcl), living in the sub-andean region of bolivia. this is the third reported case of dcl in bolivia, but the first one with isoenzymatic identification of the aetiological agents involved and the first one giving evidence for a mixed infection by 2 leishmania parasites in the same lesion. | 2002 | 12474481 |
| a putative novel nuclear-encoded subunit of the cytochrome c oxidase complex in trypanosomatids. | a relatively large nuclear-encoded polypeptide, designated trcoiv, is found in the cytochrome c oxidase (co) complex of trypanosomatids. in order to determine if this polypeptide represents a bona fide subunit of the complex, we have characterized the cdna and the gene for this polypeptide in leishmania tarentolae. its nuclear gene has no sequence similarity to mammalian coiv. the trcoiv preprotein has a long mitochondrial targeting sequence of 31 residues. the mature polypeptide cofractionates ... | 2002 | 12467979 |
| leishmania (leishmania) amazonensis-induced cutaneous leishmaniasis in the primate cebus apella: a model for vaccine trials. | a primate model of leishmaniasis was developed with the objective of future vaccine testing. lesion development and immunological parameters were studied upon primary and secondary infections. seven cebus apella were injected subcutaneously with 2 x 10(6) leishmania (leishmania) amazonensis promastigotes. erythematous nodules appeared 19-29 days p.i., which disappeared 100 days p.i. four months later, six of the monkeys were challenged with the same inoculum; three of them developed erythematous ... | 2002 | 12464422 |
| assessment of pcr in the detection of leishmania spp in experimentally infected individual phlebotomine sandflies (diptera: psychodidae: phlebotominae). | dna amplification by the polymerase chain reaction (pcr) was applied in the investigation of the presence of leishmania (kinetoplastida: trypanosomatidae) parasites in single phlebotomine sandflies. three phlebotomine/parasite pairs were used: lutzomyia longipalpis/leishmania chagasi, lutzomyia migonei/leishmania amazonensis and lutzomyia migonei/leishmania braziliensis, all of them incriminated in the transmission of visceral or cutaneous leishmaniasis. dna extraction was performed with whole i ... | 2002 | 12436164 |
| 3-[4'-bromo-(1,1'-biphenyl)-4-yl]-n, n-dimethyl-3-(2-thienyl)-2-propen-1-amine: synthesis, cytotoxicity, and leishmanicidal, trypanocidal and antimycobacterial activities. | current therapies for chagas' disease, leishmaniasis and tuberculosis are unsatisfactory because of the failure rates, significant toxicity and/or drug resistance. in this study, the compound 3-[4'-bromo-(1,1'-biphenyl)-4-yl]-n,n-dimethyl-3-(2-thienyl)-2-propen-1-amine (iv) was synthesized and its trypanocidal, leishmanicidal and antimycobacterial activities were investigated. the cytotoxicity was determined on v79 cells with three endpoints: nucleic acid content, 3-(4,5-dimethylthiazole-2-yl)-2 ... | 2002 | 12407118 |
| total synthesis and anti-leishmanial activity of some curcumin analogues. | curcumin (1) an important yellow dye isolated from curcuma longa rhizomes, exhibits a variety of pharmacological effects such as anti-inflammatory, antioxidant and antiviral activity. ten curcuminoids (2-11) were synthesized by the condensation of 2,4-pentanedione with differently substituted benzaldehydes, using the boron complex approach, which avoided knoevenagel condensation at c-3 of the diketone. the curcuminoids were assayed in vitro against leishmania amazonensis promastigotes using pent ... | 2002 | 12404885 |
| bioactivity of crude extracts and some constituents of blutaparon portulacoides (amaranthaceae). | crude extracts (aerial parts and roots, both dried), methylenedioxyflavonol, and a mixture of acyl steryl glycosides isolated from blutaparon portulacoides, were assayed for their toxicity against trypanosoma cruzi trypomastigotes and leishmania amazonensis amastigotes from axenic cultures. the antimicrobial activity was also investigated, in a screening conducted using fifteen strains of gram-positive and gram-negative bacteria, along with the yeasts, candida albicans and candida tropicalis. to ... | 2002 | 12403168 |
| the influence of dietary fish-oil supplementation on cutaneous leishmania amazonensis infection in mice. | dietary fish-oil (fo) supplementation has been shown to inhibit inflammation in various clinical disease states and to be beneficial in experimental models of inflammation and bacterial and plasmodial infection. in mice, fo increases macrophage production of tumour necrosis factor alpha (tnf). production of tnf has been reported to be important in the resistance of mice against various leishmania spp. we investigated whether dietary supplementation with fo protects susceptible balb/c mice agains ... | 2002 | 12393167 |
| a simple and reproducible method to obtain large numbers of axenic amastigotes of different leishmania species. | this work describes a simple method to yield large amounts of leishmania amastigote-like forms in axenic cultures using promastigotes as the starting population. the method described induced extracellular amastigote transformation of leishmania amazonensis (97%), leishmania braziliensis (98%) and leishmania chagasi (90%). the rounded parasites obtained in axenic cultures were morphologically similar, even at the ultrastructural level, to intracellular amastigotes. moreover, the axenic amastigote ... | 2002 | 12375160 |
| studies on quinones. part 37. synthesis and biological activity of o-aminoester functionalised benzo- and naphtho[2,3-b]thiophenequinones. | the synthesis of 3-amino-2-methoxycarbonyl-4,7-dimethoxybenzo[b]thiophene (5) and benzothieno[3,2-d][1,3]oxazin 15 from 3,6-dimethoxy-2-nitrobenzaldehyde (1) is reported. benzo[b]thiophene-4,7-quinones 9 and 10 were prepared in good yields by oxidative deprotection of the corresponding dimethoxybenzothiophenes 8 and 7. cycloaddition reaction of quinone 8 with 1-(e)-trimethylsilyloxy-1,3-butadiene followed by acid-induced aromatization provides access to naphtho[2,3-b]thiophene-4,9-quinone 13 and ... | 2002 | 12237538 |
| paracoccidioides brasiliensis-reactive antibodies in brazilian blood donors. | in a survey for primary paracoccidioidomycosis (pcm) infection (and not the clinical disease), two groups of blood donors were analyzed. one study group was drawn from donors living in a rural area where pcm is endemic, and the other group from urban residents of a large city, são paulo. anti-paracoccidioides brasiliensis (pb) specific antibodies (igg) in sera were analyzed by elisa, using crude pb exoantigens (exoag) and purified specific pb 43 kda glycoprotein (gp43). the results showed that 2 ... | 2002 | 12230218 |
| pretreatment of leishmania homologue of receptors for activated c kinase (lack) promotes disease progression caused by leishmania amazonensis. | a cdna coding leishmania homologue of receptors for activated c kinase (lack), which was known to play an important role in the early phase of leishmania infection, was molecularly cloned from leishmania amazonensis promastigote by using reverse transcription and nested polymerase chain reaction, and was sequenced. the l. amazonenis lack cdna showed 97.3 to 99.3% homology and its deduced amino acid sequence showed 98.7 to 99.7% identity in comparison with lack sequences from five other species. ... | 2002 | 12221926 |
| polymorphism analysis of the internal transcribed spacer and small subunit of ribosomal rna genes of leishmania mexicana. | leishmania mexicana causes a wide spectrum of clinical diseases. in spite of the variety of clinical forms, no data exist regarding genetic polymorphism of l. mexicana. we analyzed the polymorphism of the internal transcribed spacer (its) and the small subunit rrna genes of 3 reference strains and 24 mexican isolates of l. mexicana, by means of polymerase chain reaction and subsequent digestion by restriction enzymes. all strains of l. mexicana had invariant patterns for both the its and the sma ... | 2002 | 12209333 |
| analysis of t helper cell responses during infection with leishmania amazonensis. | most inbred strains of mice are susceptible to leishmania amazonensis infection and develop progressive cutaneous lesions. however, the role of th subsets in the disease and the molecular basis of pathogenesis are unclear. to address this issue, we examined the frequency of cytokine-producing cd4+ t cells and the profile of alphabeta t cell receptor (tcr) usage in infected balb/c mice. at different infection stages, cd4+ cells of draining lymph nodes contained comparable frequencies of th1 and t ... | 2002 | 12164286 |
| succinate secreted by trypanosoma brucei is produced by a novel and unique glycosomal enzyme, nadh-dependent fumarate reductase. | in all trypanosomatids, including trypanosoma brucei, glycolysis takes place in peroxisome-like organelles called glycosomes. these are closed compartments wherein the energy and redox (nad(+)/nadh) balances need to be maintained. we have characterized a t. brucei gene called frdg encoding a protein 35% identical to saccharomyces cerevisiae fumarate reductases. microsequencing of frdg purified from glycosome preparations, immunofluorescence, and western blot analyses clearly identified this enzy ... | 2002 | 12138089 |
| evaluation of antigens from various leishmania species in a western blot for diagnosis of american tegumentary leishmaniasis. | a western blot method that uses antigens from culture promastigote forms of leishmania (viannia) braziliensis, l. (leishmania) amazonensis, l. (leishmania) tropica, and a trypanosomatid (strain 268t) isolated from naturally infected tomatoes was evaluated for laboratory diagnosis of american tegumentary leishmaniasis (atl). serum samples were obtained from 108 patients with atl (group i), 23 chagasic patients (group ii), 32 patients with other diseases (group iii), and 78 healthy individuals (gr ... | 2002 | 12135276 |
| opsonization modulates rac-1 activation during cell entry by leishmania amazonensis. | lesions caused by leishmania amazonensis normally heal, but relapses occur due to parasite persistence in host tissues. it has been proposed that infection of fibroblasts plays an important role in this process by providing the parasites with a safe haven in which to replicate. however, most previous studies have focused on the entry of leishmania into macrophages, a process mediated by serum opsonins. to gain insight into a possible role of nonopsonic entry in the intracellular persistence of a ... | 2002 | 12117970 |
| in vitro activities of iboga alkaloid congeners coronaridine and 18-methoxycoronaridine against leishmania amazonensis. | in previous studies, we demonstrated the leishmanicide effect of coronaridine, a natural indole alkaloid isolated from stem bark of peschiera australis (delorenzi et al., antimicrob. agents chemother. 45:1349-1354, 2001). in this study we show the leishmanicidal effect of the synthetic coronaridine and its racemic 18-methoxylated analog, 18-methoxycoronaridine. both alkaloids revealed a potent leishmanicide effect against leishmania amazonensis, a causative agent of cutaneous and diffuse cutaneo ... | 2002 | 12069962 |
| nitric oxide-mediated proteasome-dependent oligonucleosomal dna fragmentation in leishmania amazonensis amastigotes. | resistance to leishmanial infections depends on intracellular parasite killing by activated host macrophages through the l-arginine-nitric oxide (no) metabolic pathway. here we investigate the cell death process induced by no for the intracellular protozoan leishmania amazonensis. exposure of amastigotes to moderate concentrations of no-donating compounds (acidified sodium nitrite nano(2) or nitrosylated albumin) or to endogenous no produced by lipopolysaccharide or gamma interferon treatment of ... | 2002 | 12065515 |
| genomic organisation and transcription characterisation of the gene encoding leishmania (leishmania) amazonensis arginase and its protein structure prediction. | the genomic organisation of the gene encoding leishmania (leishmania) amazonensis arginase as well as its flanking regions were characterised. the size of the transcribed rna was determined, allowing us to map the genomic sites signalling for rna trans-splicing and putative polyadenylation regions. the general organisation was compared with genes encoding other proteins already described in organisms of the trypanosomatid family. the complete nucleotide sequence of the arginase open reading fram ... | 2002 | 12062491 |
| genetic variation in populations of leishmania species in brazil. | the population structure of strains of leishmania (viannia) braziliensis sensu lato from pará state and paraná state in brazil, of l. (v.) shawi and l. (leishmania) amazonensis from pará state, and the relationships of type strains of the subgenera l. (viannia) and l. (leishmania) were examined by the random-amplified polymorphic deoxyribonucleic acid (rapd) technique. four different primers (m13-40, qg1, l15996 and delta gt11r) were used. the bands were analysed using the neighbor-joining (nj) ... | 2002 | 12055823 |
| molecular modeling approaches for determining gene function: application to a putative poly-a binding protein from leishmania amazonensis (lapabp). | the great expansion in the number of genome sequencing projects has revealed the importance of computational methods to speed up the characterization of unknown genes. these studies have been improved by the use of three dimensional information from the predicted proteins generated by molecular modeling techniques. in this work, we disclose the structure-function relationship of a gene product from leishmania amazonensis by applying molecular modeling and bioinformatics techniques. the analyzed ... | 2002 | 12048561 |
| technetium-99m labeling anti-amastigote polyclonal antibodies of leishmania amazonensis. | anti-amastigote polyclonal antibody (igg) was incubated with solutions of stannous chloride and sodium borohidride. after that, 3.7 mbq of technetium-99m (99mtc) was added. a labeling yield of the antibody about 84% was obtained. after filtration of 99mtc-igg, the radiochemical purity increased from 84 to 95%. the labeling of igg with 99mtc did not modify the immunoreactivity of the antibody, since it was able to identify in vitro and in vivo the specific antigen of leishmania amazonensis. | 2002 | 12031875 |
| vaccination of c57bl/10 mice against cutaneous leishmaniasis using killed promastigotes of different strains and species of leishmania. | antigenic extracts from five leishmania stocks were used to vaccinate c57bl/10 mice. the leishvacin(r) and ph8 monovalent vaccine yielded the highest ifn-gamma levels in the supernatants of spleen cell culture from vaccinated animals. each single strain immunized group showed evidence of protective immunity six months after the challenge with promastigotes of leishmania (leishmania) amazonensis. no differences were detected between the vaccinated groups. it can be concluded that vaccines compose ... | 2002 | 12011920 |
| leishmanicidal activity of two canthin-6-one alkaloids, two major constituents of zanthoxylum chiloperone var. angustifolium. | the crude alkaloidal extract of zanthoxylum chiloperone stem bark exhibited in vitro activity against various strains of leishmania ssp. at 100 microg/ml. two active major constituents were isolated and identified as canthin-6-one and 5-methoxycanthin-6-one. the effect of these compounds was also tested in an in vivo assay using balb/c mice infected with leishmania amazonensis. the mice were treated for 5 weeks postinfection with these alkaloids by oral (14 days) or intralesional route (4 days) ... | 2002 | 12007711 |
| cloning and characterization of a leucyl aminopeptidase from three pathogenic leishmania species. | aminopeptidases are emerging as exciting novel drug targets and vaccine candidates in parasitic infections. in this study, we describe for the first time an aminopeptidase from three highly pathogenic leishmania species. intronless genes encoding a leucyl aminopeptidase (lap) were cloned from leishmania amazonensis, leishmania donovani, and leishmania major, which encoded 60-kda proteins that displayed homology to leucyl aminopeptidases from gram-negative bacteria, plants, and mammals. the lap g ... | 2002 | 12006595 |
| expression and processing of megasome cysteine proteinases during leishmania amazonensis differentiation. | amastigotes of leishmania species belonging to the leishmania mexicana complex exhibit large lysosomes, called megasomes, which are rich in cysteine proteinases. various aspects of the host-parasite interaction, the differentiation process as well as intracellular survival, have been attributed to these proteinases. the in vitro differentiation from promastigote to amastigote forms of leishmania amazonensis was evaluated using the analysis of the expression of cysteine proteinase (lpcys2) by nor ... | 2002 | 11999020 |
| low-dose uvb contributes to host resistance against leishmania amazonensis infection in mice through induction of gamma interferon and tumor necrosis factor alpha cytokines. | uv radiation suppresses the immune response, a fact which raises the question of whether the phenomenon may find practical applications in the outcome of infectious diseases. in this study, balb/c mice were exposed to low-dose uvb (250 j/m(2)) from dermaray m-dmr-100 for 4 consecutive days. twelve hours after the last uv exposure, groups of mice were injected with 2 x 10(6) leishmania amazonensis promastigotes. the development of skin lesions, as assessed by measurement of visible cutaneous lesi ... | 2002 | 11986277 |
| immunochemotherapy for cutaneous leishmaniasis: a controlled trial using killed leishmania (leishmania) amazonensis vaccine plus antimonial. | leishmaniasis is endemic in 88 countries in the world, and 350 million individuals are at risk of acquiring the disease. treatment for american cutaneous leishmaniasis (acl) is long, expensive, and associated with important side-effects. | 2002 | 11982640 |
| risk factors associated with asymptomatic infection by leishmania chagasi in north-east brazil. | various factors have been associated with a predisposition to the development of clinical american visceral leishmaniasis (avl). however, little information is available about the factors that predispose to asymptomatic infection. to identify the risk factors associated with asymptomatic infection, a study was carried out between july 1997 and june 1998 on children aged 0-5 years in the districts of vila nova and bom viver in the municipality of raposa in the island of são luís, state of maranhã ... | 2002 | 11925984 |
| overexpression of the leishmania amazonensis ca2+-atpase gene lmaa1 enhances virulence. | a gene for a ca2+-transporting atpase (lmaa1) from the trypanosomatid parasite leishmania (mexicana) amazonensis was overexpressed in two clones of l. amazonensis differing in their virulence. rna and protein expression of the gene was increased in transfectants, as was the infectivity of transfectants versus parental types in both mouse and in vitro macrophage infection experiments. the virulence of the almost avirulent clone was enhanced such that it was more virulent than the parental 'virule ... | 2002 | 11896767 |
| early enhanced th1 response after leishmania amazonensis infection of c57bl/6 interleukin-10-deficient mice does not lead to resolution of infection. | c3h and c57bl/6 mice are resistant to leishmania major but develop chronic lesions with persistent parasite loads when they are infected with leishmania amazonensis. these lesions develop in the absence of interleukin-4 (il-4), indicating that susceptibility to this parasite is not a result of development of a th2 response. expression of the cytokine il-10 during infection could account for the lack of il-12 expression and poor cell-mediated immunity towards the parasite. therefore, we tested th ... | 2002 | 11895981 |
| the expression system of biologically active canine interleukin-8 in leishmania promastigotes. | it has been reported that leishmania promastigotes have ability to express foreign genes on drug selectable plasmids. to investigate further abilities of the recently described expression vector, p6.5, in the transfection of leishmania organisms (chen d-q, kolli bk, yadava n et al. episomal expression of specific sense and antisense mrnas in leishmania amazonensis: modulation of gp63 levels in promastigotes and their infection of macrophages in vitro. infect immun 2000;68:80--86), the constructe ... | 2002 | 11880228 |
| synthetic derivatives of curcumin and their activity against leishmania amazonensis. | in a previous work, the in vitro and in vivo activity of a series of diarylheptanoid derivatives against leishmania amazonensis has been described. based on the promising results, ten new compounds belonging to the same chemical class were synthesized and have been investigated in relation to their leishmanicidal activity. the compounds were obtained through several chemical modifications on the basic structure of curcumin (1,7-bis-(4-hydroxy-3-methoxyphenyl)-1,6-heptadiene-3,5-dione) in an atte ... | 2002 | 11878200 |
| characterization and cytochemical localization of an atp diphosphohydrolase from leishmania amazonensis promastigotes. | an atp diphosphohydrolase was identified in the plasma membranes isolated from promastigote forms of leishmania amazonensis. both atp and adp were hydrolysed at similar rates by the enzyme. other nucleotides such as utp, gtp and ctp were also degraded, revealing a broad substrate specificity. adding atp and adp simultaneously, the amount of hydrolysis achieved was compatible with the presence of a single enzyme. atpase activity was not affected by addition of vanadate, ouabain, thapsigargin, dic ... | 2002 | 11862992 |
| a plasma membrane p-type h(+)-atpase regulates intracellular ph in leishmania mexicana amazonensis. | a recent report (mukherjee et al., j. biol. chem. 276 (2001) 5563) has proposed that the plasma membrane mg(+)-atpase of promastigotes of leishmania donovani, that is involved in its intracellular ph regulation, is an electroneutral h(+)/k(+) antiporter rather than an electrogenic h(+) pump. since this proposition has important implications for the use of the pump as a target for chemotherapy, we investigated its nature in the mammalian stage (amastigote) of l. mexicana amazonensis and compared ... | 2002 | 11814574 |
| ultrastructural and biochemical alterations induced by 22,26-azasterol, a delta(24(25))-sterol methyltransferase inhibitor, on promastigote and amastigote forms of leishmania amazonensis. | we report on the antiproliferative effects and the ultrastructural and biochemical alterations induced in vitro by 22,26-azasterol, a sterol delta(24(25))-methyltransferase (24-smt) inhibitor, on leishmania amazonensis. when promastigotes and amastigotes were exposed to 100 nm 22,26-azasterol, complete growth arrest and cell lysis ensued after 72 (promastigotes) or 120 (amastigotes) h. exposure of parasites to this azasterol led to the complete depletion of parasite endogenous sterols (episterol ... | 2002 | 11796362 |
| extracellular release of the glycosylphosphatidylinositol (gpi)-linked leishmania surface metalloprotease, gp63, is independent of gpi phospholipolysis: implications for parasite virulence. | the major zinc metalloprotease of leishmania (gp63), an important determinant of parasite virulence, is attached to the parasite surface via a glycosylphosphatidylinositol anchor. here we report the spontaneous release of proteolytically active gp63 from a number of leishmania isolates, causing cutaneous and visceral disease. to investigate the mechanism(s) of gp63 release, we transfected a gp63-deficient variant of leishmania amazonensis with constructs expressing gp63 and various mutants there ... | 2002 | 11777912 |
| homologues of lmpk, a mitogen-activated protein kinase from leishmania mexicana, in different leishmania species. | lmpk, a mitogen-activated protein (map) kinase homologue of leishmania mexicana, is essential for the proliferation of the amastigote, the mammalian stage of the protozoan parasite. this has been demonstrated using deletion mutant promastigotes, the insect stage of the parasite: first, in vitro after differentiation to amastigotes, which subsequently lost their potential to proliferate; second, by infection of peritoneal macrophages, which were able to cope with the infection and cleared the par ... | 2001 | 11770102 |
| protein kinase a of leishmania amazonensis as a potential target for methoxy-amidine. | cyclic 3',5'-adenosine monophosphate (camp) is one of the most important signaling molecules for cell growth and differentiation in several systems including protozoal parasites such as trypanosoma cruzi and leishmania species. the most important event during leishmania developmental cycle is the differentiation of procyclic into metacyclic promastigotes, which is associated with the appearance of pathogenicity. as previously demonstrated leishmania amazonensis metacyclogenesis is associated wit ... | 2001 | 11765595 |
| attempt to differentiate leishmania (leishmania) amazonensis, l. (l.) chagasi, leishmania (viannia) braziliensis and l. (v.) guyanensis using the ssr-pcr technique. | the ability to differentiate reference strains of leishmania (leishmania) amazonensis, l. (l.) chagasi, leishmania (viannia) braziliensis and l. (v.) guyanensis was evaluated using the simple sequence repeat polymerase chain reaction (ssr-pcr) technique. this technique differentiates the leishmania species, generating distinct dna amplicon profiles. the ssr-pcr profiles were similar to but more reproducible than those produced by rapd. ssr-pcr is presented as an alternative to other molecular me ... | 2001 | 11763439 |
| differences in gamma interferon production in vitro predict the pace of the in vivo response to leishmania amazonensis in healthy volunteers. | the initial encounter of leishmania cells and cells from the immune system is fundamentally important in the outcome of infection and determines disease development or resistance. we evaluated the anti-leishmania amazonensis response of naive volunteers by using an in vitro priming (ivp) system and comparing the responses following in vivo vaccination against the same parasite. in vitro stimulation allowed us to distinguish two groups of individuals, those who produced small amounts of gamma int ... | 2001 | 11705920 |
| a randomized double-blind placebo-controlled trial to evaluate the immunogenicity of a candidate vaccine against american tegumentary leishmaniasis. | this study was aimed at evaluating the immunogenicity of a vaccine composed of killed leishmania amazonensis promastigotes using several different protocols in a randomized, double-blind and controlled trial design in order to select one of them for further efficacy trials. one hundred and fourteen leishmanin skin test (lst)-negative healthy volunteers were allocated into eight groups that received either two or three deep intramuscular injections of vaccine at doses of 180, 360 and 540 microg o ... | 2001 | 11700183 |
| inhibition of macrophage invasion by monoclonal antibodies specific to leishmania (viannia) braziliensis promastigotes and characterisation of their antigens. | monoclonal antibodies that specifically recognise leishmania (viannia) braziliensis promastigotes were produced and termed sst-2, sst-3 and sst-4. sst-2 recognises a conformational epitope present in a 24-28 kda doublet and in a 72 kda component, as verified by western blotting. indirect immunofluorescence showed that the antigen recognised by sst-2 is distributed homogeneously on the parasite surface. sst-3 recognises a flagellar glycoprotein of approximately 180 kda. the reactivity of this mab ... | 2001 | 11595232 |
| leishmania amazonensis-dendritic cell interactions in vitro and the priming of parasite-specific cd4(+) t cells in vivo. | the progressive disease following leishmania amazonensis infection in mice requires functional cd4(+) t cells, which are primed to a disease-promoting phenotype during the infection. to understand how these pathogenic t cells are generated and the role of dendritic cells (dcs) in this process, we use dcs of susceptible balb/c and resistant c3h/hej mice to examine parasite-dc interactions in vitro as well as the effector phenotype of t cells primed by parasite-exposed dcs in vivo. our results dem ... | 2001 | 11591781 |
| enhanced activity of antisense phosphorothioate oligos against leishmania amastigotes: augmented uptake of oligo, ribonuclease h activation, and efficient target intervention under altered growth conditions. | leishmania, a parasitic protozoan, infects human macrophages, often causing severe morbidity and mortality. the pathogenic form of this parasite, the amastigote, lives inside the acidic phagolysosomes of infected macrophages. in our attempt to develop anti-miniexon phosphorothioate oligodeoxyribonucleotides (s-oligos) as an alternative chemotherapy against leishmania, we found that intracellular as well as 'axenic' amastigotes were more susceptible to these s-oligos than were the cultured promas ... | 2001 | 11585054 |
| a mg-dependent ecto-atpase in leishmania amazonensis and its possible role in adenosine acquisition and virulence. | the plasma membrane of cells contains enzymes whose active sites face the external medium rather than the cytoplasm. the activities of these enzymes, referred to as ectoenzymes, can be measured using living cells. in this work we describe the ability of living promastigotes of leishmania amazonensis to hydrolyze extracellular atp. in these intact parasites whose viability was assessed before and after the reactions by motility and by trypan blue dye exclusion, there was a low level of atp hydrol ... | 2001 | 11414680 |
| pre-exposure with low-dose uva suppresses lesion development and enhances th1 response in balb/c mice infected with leishmania (leishmania) amazonensis. | this study was conducted to determine whether exposing mice to ultraviolet (uv) radiation would alter the pathogenesis of infection with leishmania (leishmania) amazonensis (l. amazonensis) which causes progressive cutaneous disease in susceptible mouse strains. balb/c mice were irradiated with 10 and 30 j/cm(2) uva on shaved skin of the back from dermaray (m-dmr-100) for 4 consecutive days before infection with leishmania promastigotes. the course of disease was recorded by measuring the size o ... | 2001 | 11390207 |
| platelet-activating factor (paf) modulates peritoneal mouse macrophage infection by leishmania amazonensis. | the effects of platelet-activating factor (paf) on the infection of peritoneal mouse macrophages by leishmania amazonensis were investigated. prior to the infection, the parasites and/or the macrophages were treated with paf and/or one of the following modulators: web 2086 (paf antagonist), and the modulators of protein kinase c, phorbol-12-myristate-13-acetate (pma), and sphingosine. the infection was inhibited when the macrophages or both the parasites and the macrophages were treated with paf ... | 2001 | 11375661 |
| role of peroxynitrite in macrophage microbicidal mechanisms in vivo revealed by protein nitration and hydroxylation. | the cytotoxins produced by phagocytic cells lacking peroxidases such as macrophages remain elusive. to elucidate macrophage microbicidal mechanisms in vivo, we compared the lesion tissue responses of resistant (c57bl/6) and susceptible (balb/c) mice to leishmania amazonensis infection. this comparison demonstrated that parasite control relied on lesion macrophage activation with inducible nitric oxide synthase expression (inos), nitric oxide synthesis, and extensive nitration of parasites inside ... | 2001 | 11368921 |
| in vitro growth of leishmania amazonensis promastigotes resistant to pentamidine is dependent on interactions among strains. | the in vitro growth of promastigote cells of leishmania amazonensis was found to strongly depend on interactions among strains that differed in their pentamidine resistance. in particular, the growth of resistant strains was reduced when they shared the same environment with a less-resistant strain. | 2001 | 11353656 |
| application of flow cytometry and microscopical methods to characterize the effect of herbal drugs on leishmania spp. | the world health organization has identified leishmania sis as a major public health problem, particularly in africa, asia, and latin america. about 1.5 to 2 million people are affected annually by this parasitic infection. as there is no vaccine, there is still a strong need for sufficient drugs. in a preliminary screening, extracts of 50 different plants were evaluated for their possible leishmanicidal activity against the promastigote form of leishmania mexicana amazonensis. eighteen extracts ... | 2001 | 11312576 |
| antileishmanial activity of an indole alkaloid from peschiera australis. | in this study, we show the leishmanicidal effects of a chloroform fraction (clf) and a purified indole alkaloid obtained from crude stem extract of peschiera australis against leishmania amazonensis, a causative agent of cutaneous leishmaniasis in the new world. in a bioassay-guided chemical fractionation, the leishmanicidal activity in clf completely and irreversibly inhibited promastigote growth. this fraction was also active against amastigotes in infected murine macrophages. chemical analysi ... | 2001 | 11302794 |
| invasive forms of toxoplasma gondii, leishmania amazonensis and trypanosoma cruzi have a positive charge at their contact site with host cells. | we examined the surface charges of invasive forms of toxoplasma gondii, leishmania amazonensis, and trypanosoma cruzi by atomic force microscopy and surface potential spectroscopy. we found that the specific part of the protozoan which makes initial contact with the host cell is positively charged. this indicates that the positive charge at the site of contact facilitates binding of the invasive protozoan to negatively charged host cells. | 2001 | 11293566 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| [canine cutaneous and visceral leishmaniasis and chagas' disease from counties in the triângulo mineiro and alto paranaíba regions, minas gerais state, brazil] | leishmaniasis and chagas' disease were surveyed by indirect immunofluorescence with sera from 331 dogs from uberlândia and coromandel, two counties in the state of minas gerais, brazil. leishmania amazonensis and trypanosoma cruzi antigens were employed. in uberlândia county, 230 sera were studied, of which 200 were from urban areas and 30 rural: 4.5% of urban samples and 6.6% of rural were positive for l. amazonensis antigen. of 89 sera from coromandel, 5.6% were positive for the same test to l ... | 1996 | 10904334 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |