| experimental transmission of leishmania chagasi, causative agent of neotropical visceral leishmaniasis, by the sandfly lutzomyia longipalpis. | | 1977 | 859627 |
| partial characterization of leishmania chagasi promastigote peptidases. | | 1992 | 1308575 |
| immunologic markers of clinical evolution in children recently infected with leishmania donovani chagasi. | the study attempted to identify immunologic markers for progression of leishmania donovani chagasi infection to disease in children in an area endemic for visceral leishmaniasis (vl). [3h]thymidine uptake of lymphocytes stimulated with l. donovani chagasi antigen from children with asymptomatic infection (25,286 +/- 11,648) and from children with self-healing subclinical infection (15,511 +/- 4681) was greater (p = .001) than that observed with lymphocytes from children who progressed to classic ... | 1992 | 1347057 |
| three distinct rnas for the surface protease gp63 are differentially expressed during development of leishmania donovani chagasi promastigotes to an infectious form. | leishmania sp. protozoa contain an abundant surface protease (gp63) that is important for the virulence of the parasite. we found that the average amount of gp63 expressed by leishmania donovani chagasi promastigotes increases 6-11-fold as they develop from a less infectious form in logarithmic phase to a highly infectious form during stationary phase of cultivation in vitro. the predominant gp63 rna switches from a 2.7 to a 3.0 kilobase (kb) rna during the transition from log to stationary phas ... | 1992 | 1370484 |
| epidemiology of visceral leishmaniasis in northeast brazil. | epidemiologic aspects of the relationship between infection with leishmania chagasi and development of clinical visceral leishmaniasis (vl) were studied in all children < 11 years old in a defined, endemic, rural area of the state of ceará in northeast brazil. antileishmanial antibodies were measured in the same subjects by elisa on six occasions between may 1987 and august 1989. seroconversion was documented during this period in 108 children, with a cumulative annual incidence of 4.6%. twelve ... | 1992 | 1402024 |
| host preferences of the phlebotomine sandfly lutzomyia longipalpis in amazonian brazil. | experiments were undertaken to determine the relative attractiveness of humans, dogs and chickens to lutzomyia longipalpis, the principal vector of leishmania chagasi causing american visceral leishmaniasis. field experiments in two villages on marajó island, pará state, brazil, showed that one boy attracted significantly more flies than one dog or chicken, and slightly fewer flies than a group of six chickens. experiments with laboratory-bred female flies showed that a significantly greater num ... | 1992 | 1421498 |
| leishmania chagasi antigens recognized in cured visceral leishmaniasis and asymptomatic infection. | active visceral leishmaniasis is associated with antigen-specific immuno-suppression. however, cured patients develop a cellular immune response associated with resistance to reinfection. recent studies have identified patients with asymptomatic or subclinical infections, which are also accompanied by an immune response. in order to identify subjects immune to leishmania chagasi, we performed a skin-test survey in an endemic area in eastern venezuela. the delayed-type hypersensitivity (dth) resp ... | 1992 | 1539745 |
| cytokine activation of human macrophages infected with hiv-1 to inhibit intracellular protozoa. | peripheral blood mononuclear cells (pbmcs) from hiv-seronegative donors were infected in vitro with hiv-1. infection was monitored by cytopathology, supernatant p24 antigen, and by immunocytochemical staining. after 14 days in culture, approximately 70-90% of the cells became infected with hiv, as indicated by cell fusion and immunostaining for virus. at this time, recombinant huifn-gamma was added to the cultures, followed by infection 24 h later with the intracellular protozoan parasites toxop ... | 1992 | 1613664 |
| hydrogen peroxide-mediated toxicity for leishmania donovani chagasi promastigotes. role of hydroxyl radical and protection by heat shock. | leishmania must survive despite exposure to the toxic oxidant hydrogen peroxide (h2o2) during phagocytosis by macrophages. we investigated the mechanism of h2o2 toxicity for l. donovani chagasi promastigotes, and factors responsible for their relative h2o2 resistance. there was a dose-dependent toxic effect of h2o2 for promastigotes isolated during logarithmic phase of growth. in contrast, stationary phase promastigotes were less susceptible to h2o2 toxicity, and more infectious for balb/c mice. ... | 1991 | 1658042 |
| leishmania donovani chagasi: new clinical variant of cutaneous leishmaniasis in honduras. | during surveillance for endemic visceral leishmaniasis on an island off the pacific coast of honduras, an unusual form of cutaneous leishmaniasis was encountered. by clinical and laboratory criteria, 17 cases were identified over 5 months; children aged 4 to 15 years were primarily affected. lesions were generally few in number, small, always papular, and non-ulcerative, even when present for several years. patients with skin lesions seemed otherwise healthy and were well nourished. montenegro s ... | 1991 | 1670724 |
| patients infected with leishmania donovani chagasi can have antibodies that recognize heat shock and acidic ribosomal proteins of trypanosoma cruzi. | | 1991 | 1723150 |
| heterogeneity of the genes encoding the major surface glycoprotein of leishmania donovani. | the major surface glycoprotein of leishmania (gp63) is present on all known species of leishmania and likely plays an integral role during the infection of macrophages in the mammalian host. to identify regions of gp63 which may be of functional significance, the nucleotide sequence of a gene encoding gp63 of leishmania donovani was determined and compared to the sequences reported for gp63 genes of leishmania major and leishmania chagasi. the gp63 nucleotide and predicted protein sequence was h ... | 1991 | 1762629 |
| effect of trypsin and 2-mercaptoethanol on the exposure of sugar residues on the surface of leishmania donovani chagasi. | using transmission electron microscopy, gold-labeled lectins, morphometry and enzyme-linked lectin assay, we could show that treatment of promastigotes of leishmania donovani chagasi with trypsin did not interfere with the binding of lectins (concanavalin a, peanut agglutinin, wheat germ agglutinin and ricinus communis agglutinin) to the parasite surface. these observations are in agreement with results we previously obtained using a biochemical approach. treatment of fixed promastigotes with 2- ... | 1991 | 1792223 |
| gamma interferon production by lymphocytes from children infected with l. chagasi. | the present study was performed to evaluate the ability of lymphocytes from 18 children living in an endemic area of visceral leishmaniasis (vl) to produce gamma-interferon. these children had no previous history of vl and were considered to be infected with leishmania chagasi based on leishmanial seroconversion. the gamma ifn levels were determined by radioimmunoassay on supernatants of lymphocyte cultures (3 x 10(6)/ml) stimulated with pha (final dilution 1:10) and leishmania chagasi antigen ( ... | 1991 | 1797267 |
| differences between leishmania (leishmania) chagasi, l. (l.) infantum and l. (l.) donovani as shown by dna fingerprinting. | | 1991 | 1842444 |
| antigenic specificity of the 72-kilodalton major surface glycoprotein of leishmania braziliensis braziliensis. | we examined the expression and the antigenicity of the major surface polypeptides of leishmania braziliensis braziliensis and leishmania donovani chagasi, parasites which commonly coexist in the same endemic areas of bolivia. sodium dodecyl sulfate-polyacrylamide gel electrophoresis protein profiles from surface-iodinated promastigotes showed the presence of a unique iodinatable polypeptide of 72 kda on the l. b. braziliensis surface and of two major components of 65 and 50 kda exposed at the su ... | 1991 | 2037677 |
| in vitro responses to leishmania antigens by lymphocytes from patients with leishmaniasis or chagas' disease. | t cell responses are correlated with recovery from and resistance to leishmaniasis. antigens of leishmania chagasi were evaluated by determining their ability to elicit in vitro proliferation and cytokine production in peripheral blood lymphocytes and in t cell lines and clones from patients with histories of leishmaniasis or chagas' disease. antigens tested were selected by their reactivity with patient antibodies. several of the antigens induced proliferative responses in peripheral blood lymp ... | 1990 | 2107208 |
| canine visceral leishmaniasis in northeast brazil: assessment of serodiagnostic methods. | domestic dogs are considered to be a major reservoir of leishmania donovani chagasi in northeast brazil, and the elimination of infected dogs is an important part of the control program. we assessed 2 serological methods, ifa and elisa. of 405 dogs, 8% were positive by ifa obtained from blood collected by drying onto filter paper followed by elution, 17% were positive by ifa performed using sera, and 38% were positive by elisa on the same sera. thirty-five dogs, seropositive by 1 or more of the ... | 1990 | 2156463 |
| the major leishmania donovani chagasi surface glycoprotein in tunicamycin-resistant promastigotes. | two populations of leishmania donovani chagasi promastigotes resistant to the lethal effects of tunicamycin (tm), an inhibitor of n-linked glycosylation, were raised. these parasites exhibited altered patterns of glycosylation when compared to wild-type controls. in particular the major surface glycoprotein gp63 was present in membranes of one population of tm-resistant promastigotes (population 1) primarily in a deglycosylated form, which migrated at a lower mr than wild-type gp63. the deglycos ... | 1990 | 2191040 |
| lutzomyia evansi, an alternate vector of leishmania chagasi in a colombian focus of visceral leishmaniasis. | | 1990 | 2278068 |
| experimental visceral leishmaniasis: sequential events of granuloma formation at subcutaneous inoculation site. | hamsters were inoculated with io7 leishmania (leishmania) chagasi amastigotes in the hind footpads and killed at 7, 15, 30, 45, 60, 75 and 90 days after infection. we observed mononuclear inflammatory infiltrates with many parasites on the 7th and 15th days of infection. on the 30th day there was early granuloma formation. after 45 days the lesion was characterized by well defined epithelioid granuloma with multinuclear giant cells whose cytoplasm showed schaumann bodies. non-particulate antigen ... | 1990 | 2278823 |
| leishmania gp63 molecule implicated in cellular adhesion lacks an arg-gly-asp sequence. | the parasitic protozoa leishmania are intracellular pathogens which enter host cells through largely undefined mechanisms. one molecule thought to play an important role in this process is gp63, the major glycoprotein on the surface of the infective promastigote form. we have cloned and analyzed the gp63 gene from leishmania chagasi, an etiologic agent of acute visceral leishmaniasis. the predicted amino acid sequence is highly homologous to that reported for leishmania major, with the exception ... | 1990 | 2320059 |
| lysosomal depletion in macrophages from spleen and foot lesions of leishmania-infected hamster. | analysis of lysosomes through acid phosphatase cytochemistry at the electron microscopy level has been performed in spleen and foot lesions from leishmania-infected hamsters. the results showed that there is lysosomal depletion in macrophages from leishmania donovani chagasi-infected hamster spleen and similar findings were obtained from foot lesions of leishmania mexicana amazonensis-infected hamsters. the distribution of acid phosphatase and thiamine pyrophosphatase was also examined in the go ... | 1990 | 2373189 |
| immune responses to t-dependent and t-independent antigens during visceral leishmaniasis in mice: evidence for altered t-cell regulation of immune responses to non-parasite antigens. | antibody responses to t-dependent and t-"independent" antigens were studied in disease-susceptible (balb/c and c57bl/10) and disease-resistant (a/j) mice infected with leishmania donovani chagasi. disease-susceptible mice but not disease-resistant mice showed a transient decrease in pfc responses to tnp on a t-dependent carrier (bgg) during the period of 4-8 weeks after infection. infected disease-susceptible animals also showed increased responses to tnp on a type ii t-independent carrier (fico ... | 1985 | 2424616 |
| trypsin-treated and coomassie blue-stained epimastigote antigen in a microagglutination test for chagas' disease. | a microagglutination test using trypsin-treated and coomassie blue-stained trypanosoma cruzi epimastigote antigen was adapted for the diagnosis of chagas' disease. when incorporated in the test, 2-mercaptoethanol treatment of chagasic sera had no influence on antibody titer. in contrast, titers in sera from patients with visceral leishmaniasis, african trypanosomiasis, and autoimmune disorders, subjected to similar treatment, showed remarkable decline. accordingly, a lower cut-off point for chag ... | 1987 | 2440329 |
| human visceral leishmaniasis: analysis of the specificity of humoral immune response to polypeptides of leishmania donovani chagasi. | soluble antigens from leishmania donovani chagasi were studied in terms of their ability to react with sera from human visceral leishmaniasis. thirty-six polypeptides, with molecular weights ranging from 14,400 to 123,000 were demonstrated by western blot analysis. an extensive cross-reactivity with sera from patients with cutaneous leishmaniasis and chagas' disease also was observed. two polypeptides (mr 119,000 and 123,000) reacted with all the sera from visceral leishmaniasis patients. when t ... | 1987 | 2444121 |
| cerdocyon thous (l.) (carnivora, canidae) naturally infected with leishmania donovani chagasi (cunha & chagas, 1973) in corumbá (mato grosso do sul state, brazil). | | 1988 | 2593825 |
| didelphis marsupialis, an apparent wild reservoir of leishmania donovani chagasi in colombia, south america. | | 1989 | 2609371 |
| [optical and electron microscopic study of the kidney of dogs naturally and experimentally infected with leishmania (leishmania) chagasi]. | two naturally infected dogs (male and female) from teófilo otoni (mg-brazil) were maintained for 18 months in our laboratory. two other dogs, two months old males were infected with 1 x 10(6) promastigotes of mho/br/70/bh46 leishmania (leishmania) chagasi strain, endovenous route, and autopsied after 10 months and two years. the main findings concerning the kidney were: (1) focal or diffuse mesangial glomerulonephritis with proliferative and enlargement of mesangial cells; (2) increase in thickn ... | 1989 | 2617010 |
| leishmania donovani donovani and leishmania donovani chagasi as antigens in a direct agglutination assay for the diagnosis of kala-azar. | the need for a reliable method for the immunological diagnosis of kala-azar is imperative. leishmania donovani donovani and l. donovani chagasi culture promastigotes were compared as antigens in a direct agglutination test (dat) for the diagnosis of visceral leishmaniasis in brazil. both antigens were successfully employed for the dat, showing 100% sensitivity and greater than 98% specificity when used to test sera from brazilian and african kala-azar, chagas' disease, malaria, filaria and syphi ... | 1989 | 2620171 |
| evaluation of antibody responses in american visceral leishmaniasis by elisa and immunoblot. | american visceral leishmaniasis (avl) is an important disease among children of northeast brazil. in order to characterize antibody responses during avl, sera of hospitalized patients were analyzed by elisa and western blot using a leishmania chagasi antigen preparation. the elisa was positive (absorbance greater than or equal to 0.196) at a serum dilution of 1:1024 in all patients at presentation, and fell to ward control levels over the following year. only one of 72 control subjects tested po ... | 1989 | 2635749 |
| epidemiology of visceral leishmaniasis in colombia. | epidemiologic studies were conducted during the period 1986-1988 in a small rural community in colombia (el callejon) where visceral leishmaniasis is highly endemic. in this community of 185 people, 14 cases of infantile visceral leishmaniasis were diagnosed in the 9 years 1981-1988. leishmanin skin testing of a sample of the human residents showed that prevalence of leishmania chagasi infection increased with age; overall, 51.2% of the subjects had a positive reaction. a canine surveillance pro ... | 1989 | 2729506 |
| characterization of integral membrane proteins of leishmania major by triton x-114 fractionation and analysis of vaccination effects in mice. | the total integral membrane proteins of promastigotes of leishmania major were extracted by using the triton x-114 phase separation technique and were characterized by immunoprecipitation, western blotting (immunoblotting), and lectin chromatography. of the 40 or more proteins which partitioned into the detergent phase, only about 10 proteins could be surface radioiodinated on live promastigotes, suggesting their surface orientation. the abundance of the gp58-63 antigen varied markedly between t ... | 1989 | 2731987 |
| expression of the major surface glycoprotein of leishmania donovani chagasi in virulent and attenuated promastigotes. | using both hamster and mouse models of infection, we documented that the virulence of leishmania donovani chagasi promastigotes decreases over time, when parasites are maintained in long term culture after isolation from an infected animal. concomitant with this loss of virulence is a marked decrease in amount of the major promastigote surface glycoprotein, gp63, present in promastigotes. the latter was shown by a decrease in binding of polyclonal anti-gp63 serum to attenuated (cultivated long t ... | 1989 | 2738406 |
| ultrastructural development of leishmania chagasi in its vector, lutzomyia longipalpis (diptera: psychodidae). | the development of leishmania chagasi, etiologic agent of american visceral leishmaniasis, was studied by light and electron microscopy in the gut of the sand fly, lutzomyia longipalpis, a natural vector. new aspects of suprapylarian leishmania behavior were elucidated. in the sand fly midgut, amastigotes transformed into promastigotes (division promastigote i) during a first division sequence within the bloodmeal. secondary division of these promastigotes resulted in a second form (division pro ... | 1989 | 2802019 |
| leishmania (viannia) naiffi sp. n., a parasite of the armadillo, dasypus novemcinctus (l.) in amazonian brazil. | a new leishmanial parasite, leishmania (viannia) naiffi sp. n., is described from the nine-banded armadillo, dasypus novemcinctus (edentata: dasypodidae), from para state, north brazil. the parasite grows luxuriantly in diffco blood-agar medium (b47), but poorly in the skin of intradermally inoculated hamsters. a comparison of isoenzyme profiles by starch gel electrophoresis separates the parasite from l. (v) braziliensis and l. (v.) guyanensis by the enzymes asat, alat, pgm, gpi, g6pd, pep, mpi ... | 1989 | 2930120 |
| the major surface protein of leishmania promastigotes is a fibronectin-like molecule. | the major surface glycoprotein of leishmania chagasi promastigotes showed crossreactivity with fibronectin (fn), a large glycoprotein that is a major constituent of the extracellular matrix of most mononuclear cells. polyclonal and monoclonal antibodies against fn precipitated two molecules of 63-58 kda from the lysates of both 125i and [35s]methionine-labeled promastigotes. in addition, a monoclonal antibody against a 15-kda fragment of fn containing the arg-gly-asp-ser (rgds) sequence and seve ... | 1988 | 2965651 |
| evolution of the genus leishmania as revealed by comparisons of nuclear dna restriction fragment patterns. | restriction endonuclease dna fragment patterns have been used to examine the relationships among 28 isolates of leishmania as well as crithidia, endotrypanum, and trypanosoma cruzi. fragments of nuclear dna were generated with six restriction enzymes, and blots were hybridized with probes from three loci. among the major lineages the fragment patterns are essentially completely different, while within the major lineages various degrees of divergence are found. molecular evolutionary trees were c ... | 1987 | 3025876 |
| evaluation of the micro enzyme-linked immunosorbent assay (elisa) for antibodies in american visceral leishmaniasis: antigen selection for detection of infection-specific responses. | this study was designed to evaluate the elisa for diagnosis of american visceral leishmaniasis (avl) using antigen prepared from different leishmania isolates and from a strain of trypanosoma cruzi. two leishmania donovani chagasi isolates from bahia and maranhão (both states of northern brazil), one l. donovani from sudan, one l. mexicana amazonensis isolate, and one t. cruzi isolate were used. a total of 375 sera were tested, including 119 from avl patients, 96 from nonleishmaniasis hospitaliz ... | 1986 | 3080918 |
| identification of leishmanial antigens in the sera of patients with american visceral leishmaniasis. | circulating immune complexes are present in the sera of patients with visceral leishmaniasis caused by leishmania donovani chagasi. in order to determine whether these complexes contain parasite antigens, sera were collected from brazilian patients with visceral leishmaniasis and from hospitalized control subjects with other diagnoses. high-molecular-weight complexes were precipitated from pooled sera with 2.5% polyethylene glycol. approximately 140-fold-more protein was precipitated from patien ... | 1988 | 3182074 |
| an in vitro method for long-term maintenance of leishmania donovani chagasi. | | 1988 | 3188150 |
| an enzyme-linked lectin assay for the study of lectin receptors of leishmania. | an enzyme-linked lectin assay (ella) based on the elisa assay, using intact formalin-fixed promastigotes to coat poly-l-lysine-treated microtiter plates is described. the assay was used to study the lectin receptors of leishmania donovani chagasi, l. donovani donovani and l. mexicana amazonensis. cona, rca, wga, and pna receptors were found in the three parasites. sba receptors were found to be as frequent as the other receptors in l. donovani chagasi but not in the other two parasites which sho ... | 1988 | 3228632 |
| epidemiological studies on american leishmaniasis in ceará state, brazil. molecular characterization of the leishmania isolates. | two methods of molecular characterization, using monoclonal antibodies and enzyme electrophoresis, were employed in the identification of 36 stocks of leishmania isolated from human and canine cases of american visceral (avl) and cutaneous (acl) leishmaniases in the northern part of ceará state, brazil. molecular homogeneous strains of leishmania donovani (chagasi) isolated from both human and canine hosts were detected in 14 municipalities. two more parasite species, l. braziliensis braziliensi ... | 1988 | 3256276 |
| the transmission of suprapylarian leishmania by the bite of experimentally infected sand flies (diptera: psychodidae). | lutzomyia furcata transmitted leishmania chagasi to a hamster 10 days after being experimentally fed on an infected spleen. an individual female psychodopygus carrerai carrerai that had fed on a hamster lesion caused by leishmania mexicana amazonensis transmitted this parasite 6 days later to another hamster. transmission electron microscopy of this fly's head revealed a small number of degenerate promastigotes in the foregut, but only a few were attached. | 1987 | 3333811 |
| the major concanavalin a-binding surface glycoprotein of leishmania donovani chagasi promastigotes is involved in attachment to human macrophages. | leishmania donovani, the protozoan causing visceral leishmaniasis, is an obligate intracellular parasite of mammalian macrophages. considerable evidence has suggested that the ingestion of l. donovani promastigotes by macrophages occurs via receptors on the surface of the phagocyte. during this study, a glycoconjugate that may be involved in the receptor-mediated ingestion of l. donovani chagasi promastigotes was isolated from the parasite membrane. octyl glucoside-soluble extracts of promastigo ... | 1988 | 3379307 |
| identification of specific and cross-reactive antigens of leishmania donovani chagasi by human infection sera. | cloned leishmania donovani chagasi (ldc) promastigotes were analyzed by sds-page separation and immunoblotting with human infection sera. the patterns of antigen reactivity were compared by using sera from individuals with ldc, leishmania mexicana amazonensis (lma), trypanosoma cruzi, mycobacterium tuberculosis, or mycobacterium leprae infections. sera from individuals with these infections recognized ldc antigens in several m.w. ranges. reactivity was due to recognition of ldc molecules and not ... | 1987 | 3543131 |
| active cutaneous leishmaniasis in brazil, induced by leishmania donovani chagasi. | l.d. chagasi was isolated from active cutaneous leishmaniasis in both human and canine infections in an endemic area in rio de janeiro, brazil. both isolates were identified by molecular and immunological characterization of the parasite using three different methods: electrophoretic mobility of isoenzymes; restriction endonuclease fragment analysis of kdna and serodeme analysis using monoclonal antibodies. this seems to be the first well documented case in the new world of a "viscerotropic" lei ... | 1986 | 3574128 |
| identification of a major 72 kilodalton surface antigen in twelve isolates of leishmania braziliensis braziliensis. | the study of the surface antigens of leishmania braziliensis braziliensis revealed a great homogeneity among ten strains isolated from bolivia and two reference strains from brazil and belize. a 72 kda major protein, present in all l. b. braziliensis strains, was recognized by both cutaneous and mucocutaneous human sera, but was not recognized by kala-azar and chagasic sera. no cross-reactive antigens were found among strains of leishmania braziliensis guyanensis, leishmania braziliensis panamen ... | 1987 | 3627165 |
| a method for the purification of leishmania promastigotes from infected phlebotomine sandflies. | we describe a method for the purification of leishmania promastigotes, isolated from infected sandflies (lutzomyia longipalpis) using a discontinuous density centrifugation gradient (percoll/homem). the sandflies, infected seven days previously with leishmania donovani chagasi or leishmania mexicana mexicana from culture, were homogenized and centrifuged on a percoll discontinuous gradient. five interface bands were formed, and most of the promastigotes settled out at the interface between the ( ... | 1987 | 3675038 |
| leishmania chagasi: in vitro differentiation of promastigotes monitored by flow cytometry. | a sequential development from a less infective to an infective stage of leishmania promastigotes growing in culture has been previously reported. the aim of this work was to investigate whether freeze-fracture electron microscopy and flow cytometry would be able to provide some reliable morphological markers of in vitro differentiation of leishmania chagasi promastigotes. the flow cytometry technique discriminates between the l. chagasi promastigotes from the different stages of their in vitro d ... | 1987 | 3678443 |
| american visceral leishmaniasis: on the origin of leishmania (leishmania) chagasi. | | 1987 | 3686647 |
| the pathology of experimental visceral leishmaniasis in resistant and susceptible lines of inbred mice. | 1. the main pathological features of experimental visceral leishmaniasis were characterized in resistant and susceptible inbred mouse strains. 2. disseminated granulomas containing parasitized macrophages were found especially in the liver and spleen of two inbred mouse strains, i.e. the resistant dba/2 and the susceptible c57bl/10 strains, which had been inoculated with leishmania donovani chagasi amastigotes. 3. the lesions tended to remain granulomatous in nature even during the early acute p ... | 1987 | 3690047 |
| leishmaniasis in brazil. xxii: characterization of leishmania from man, dogs and the sandfly lutzomyia longipalpis (lutz & neiva, 1912) isolated during an outbreak of visceral leishmaniasis in santarém, pará state. | during epidemiological studies on an outbreak of visceral leishmaniasis in santarém, pará state, north brazil, isolates of leishmania from two children, three dogs and six naturally infected specimens of the sandfly lutzomyia longipalpis were compared, biochemically, by starch-gel enzyme electrophoresis. they have proved to be indistinguishable from each other, and from a reference strain of leishmania chagasi cunha & chagas, 1937 from a case of human visceral leishmaniasis from bahia state, nor ... | 1986 | 3726975 |
| the retained capacity of lutzomyia longipalpis (lutz & neiva) to transmit leishmania chagasi (cunha & chagas) after eight years (64 generations) in a closed laboratory colony. | a closed lutzomyia longipalpis colony, from ceará has been used to transmit leishmania chagasi isolated from a fox in pará state. the last time this colony was successfully used in similar transmission experiments was eight years (64 generations) ago indicating that this colony of lu. longipalpis has fully maintained its vectorial capacity in spite of such a long period of maintainance in the laboratory. | 1985 | 3837170 |
| selection of a skin test antigen for american visceral leishmaniasis. | studies were designed to examine skin test responses to leishmanial antigens in american visceral leishmaniasis (avl) in brazil. we found that after recovery from avl, patients had positive delayed hypersensitivity reactions to leishmania. different amounts of a soluble extract obtained from leishmania donovani chagasi promastigotes were compared with whole l. d. chagasi promastigotes in persons with past avl. the most effective soluble preparations tested contained 25 and 50 micrograms leishman ... | 1986 | 3946739 |
| leishmaniasis in brazil. xxi. visceral leishmaniasis in the amazon region and further observations on the role of lutzomyia longipalpis (lutz & neiva, 1912) as the vector. | further evidence is presented incriminating the sandfly lutzomyia longipalpis as the vector of leishmania chagasi, the causative agent of american visceral leishmaniasis, in the amazon region of brazil. during an outbreak of the disease in santarém, pará state, this insect was shown to be the only species of sandfly consistently present in and around the patient's homes, where it often occurred in very large numbers. of 491 specimens dissected, 35 (7.14%) proved to be infected, and isolates of l ... | 1985 | 4002291 |
| [experimental infection of calomys callosus (rodentia-cricetidae) with leishmania donovani chagasi (laison, 1982)]. | | 1984 | 6393312 |
| immunofluorescent antibody test in american visceral leishmaniasis: sensitivity and specificity of different morphological forms of two leishmania species. | this study was designed to determine which morphologic form and species of leishmania is most suitable for detection of antibody in sera from american visceral leishmaniasis (avl) patients by the indirect fluorescent antibody test (ifat). promastigotes and amastigotes of leishmania mexicana or leishmania donovani chagasi were used as sources of antigen. a total of 70 sera, including 30 from avl patients, 30 from healthy subjects and 10 from chagas' disease patients, were used in the study. titer ... | 1983 | 6407345 |
| leishmania chagasi and l. donovani: experimental infections in domestic cats. | the susceptibility of domestic cats to visceral leishmaniasis was examined by inoculating cats with amastigotes of leishmania donovani and l. chagasi by the intravenous route, and with promastigotes of l. chagasi by the intradermal route. parasites were recovered from intravenously inoculated cats as long as 16 weeks after inoculation, but parasites apparently did not locate in the viscera in cats inoculated intradermally. parasites were not detected in intravenously inoculated cats killed at 24 ... | 1984 | 6479284 |
| leishmaniasis in brazil. xix: visceral leishmaniasis in the amazon region, and the presence of lutzomyia longipalpis on the island of marajó, pará state. | sporadic cases of visceral leishmaniasis in amazonian brazil appear limited to pará state, in the lower amazon valley and principally near the atlantic coast. the fox cerdocyon thous (l.) has been incriminated as a natural host of the causative parasite, leishmania donovani chagasi, but past doubts have existed over the identification of the most likely vector as lutzomyia (lutzomyia) longipalpis (lutz & neiva, 1912). investigations on two of five recent cases of visceral leishmaniasis of man in ... | 1983 | 6623589 |
| visceral leishmaniasis in the german shepherd dog. i. infection, clinical disease, and clinical pathology. | two groups of three german shepherd dogs each were inoculated with leishmania chagasi or leishmania donovani amastigotes and the infection was followed for 82 days. the dogs developed a persistent infection, became thin, and developed splenomegaly and lymphadenomegaly by 55 days after inoculation. all dogs developed a normocytic, normochromic anemia of increasing severity. thrombocytopenia and leukopenia occasionally occurred. blood tryptophan levels were decreased significantly in infected dogs ... | 1984 | 6710816 |
| visceral leishmaniasis in the german shepherd dog. ii. pathology. | three german shepherd dogs were inoculated with leishmania chagasi and three with leishmania donovani and the infection was followed for 82 days. all infected dogs developed splenomegaly and lymphadenomegaly. in lymph nodes there was a reduction in lymphocyte population in paracortical areas, extensive proliferation of macrophages in paracortical areas and medullary cords, follicular hyperplasia, and increased numbers of plasma cells. the spleen had decreased numbers of lymphocytes in periarteri ... | 1984 | 6710817 |
| treatment of experimental visceral leishmaniasis with lymphokine encapsulated in liposomes. | highly susceptible mice were infected with leishmania donovani chagasi and were treated with supernatants, free or encapsulated in liposomes, from concanavalin a-stimulated or unstimulated mouse spleen cell cultures. treatment consisted of multiple i.v. injections beginning 2 days before to 2 days after infection. mice treated with lymphokine-rich supernatants encapsulated in liposomes had significantly fewer liver parasites than the control groups, demonstrating in vivo activity of lymphokine a ... | 1984 | 6725947 |
| experimental leishmania chagasi infections in the marmoset callithrix jacchus jacchus. | | 1981 | 6795773 |
| leishmaniasis in brazil: xviii. further evidence incriminating the fox cerdocyon thous (l) as a reservoir of amazonian visceral leishmaniasis. | major endemic areas of visceral leishmaniasis in brazil are located in the drier, poorly forested regions, principally in the northeastern states such as ceará and bahia. cases of the human disease in the amazon region are rare, very sporadic, and seldom present opportunities for epidemiological study. following the report of a fatal case near salvaterra, the island of marajó, pará state, a preliminary investigation has resulted in the isolation of a parasite regarded as leishmania donovani chag ... | 1982 | 7164150 |
| cell-mediated immunity in american visceral leishmaniasis: reversible immunosuppression during acute infection. | cell-mediated immunity was assessed in 14 brazilian patients with acute untreated american visceral leishmaniasis (avl) and in 11 healthy patients successfully treated 1 to 14 years previously. the diagnosis of avl was established by demonstration of leishmania in bone marrow aspirates. the responsiveness of peripheral blood mononuclear cells to leishmania chagasi antigens and phytohemagglutinin was studied in vitro. soluble preparations of l. chagasi antigens were obtained from frozen-thawed pr ... | 1981 | 7275314 |
| possible origins of leishmania chagasi. | | 1980 | 7469570 |
| age structure, blood-feeding behavior, and leishmania chagasi infection in lutzomyia longipalpis (diptera: psychodidae) at an endemic focus of visceral leishmaniasis in colombia. | ecological studies on the sand fly lutzomyia longipalpis (lutz & neiva) were conducted during 1990-1992 in a small rural community in colombia where american visceral leishmaniasis (avl) is endemic. subsamples of sand flies collected weekly from pigpens, the interior of houses, and natural outdoor resting sites were dissected to determine physiological age and leishmania chagasi cunha & chagas infection rates. eleven female l. longipalpis had flagellates in their gut, 2 of which were successfull ... | 1995 | 7473616 |
| short report: extended follow-up of the natural history of persons infected with leishmania chagasi. | a five-year follow-up of the natural history of 924 children exposed to or infected with leishmania chagasi was conducted in a rural area of northeast brazil. seventy-eight percent of the children sought were located. there was no evidence of smoldering disease or long subclinical latency in this population. the overall prevalence of clinical visceral leishmaniasis in this population was 6.1%, with a mortality rate of 10%. | 1995 | 7485687 |
| antigens shared by leishmania species and trypanosoma cruzi: immunological comparison of the acidic ribosomal p0 proteins. | patients with visceral leishmaniasis produce high levels of immunoglobulin, but the specificities of antibodies produced are not well characterized. in an effort to identify leishmania antigens that are specific to leishmania species or are cross-reactive with other parasitic protozoa, we have cloned and characterized full-length genomic and cdna clones encoding a leishmania chagasi acidic ribosomal antigen, lcp0, recognized during human infections. the protein is homologous to the trypanosoma c ... | 1994 | 7513304 |
| identification of leishmania chagasi antigens recognized by human lymphocytes. | preparative sds-page followed by electroelution was used to separate proteins of leishmania chagasi promastigotes into 67 fractions. these fractions were tested for the ability to stimulate proliferation of peripheral blood mononuclear cells from healthy immune donors who were treated previously for visceral leishmaniasis and from nonimmune controls. the proliferative responses elicited by these proteins varied among individuals. the 69-kda protein fraction contained a fragment with sequence sim ... | 1995 | 7561180 |
| comparison of new and old world leishmanins in an endemic region of brazil. | the control of leishmaniasis depends on a knowledge of the magnitude of the disease and of exposure to it. delayed-type hypersensitivity testing can detect prior exposure to the parasite, but there is little agreement regarding the choice of an antigen for such testing. new and old world leishmanins were tested in a study of patients with confirmed prior cutaneous leishmaniasis (cl), patients with confirmed prior american visceral leishmaniasis (avl), and controls from areas in espírito santo, b ... | 1995 | 7620013 |
| molecular cloning, characterization, and expression in escherichia coli of iron superoxide dismutase cdna from leishmania donovani chagasi. | | 1995 | 7642321 |
| mapping human t cell epitopes in leishmania gp63. identification of cross-reactive and species-specific epitopes. | both a conserved surface metalloprotease of leishmania, gp63 as well as certain gp63-derived peptides, have been shown to have immunoprophylactic potential in mouse models of leishmaniasis. in addition, pbmc from individuals with cutaneous, mucosal, or cured visceral leishmaniasis respond in vitro to both native and rgp63. in this report, we mapped human t cell epitopes within gp63. t cells from leishmaniasis patients responded in vitro to certain peptides of gp63 by proliferation and ifn-gamma ... | 1993 | 7678627 |
| developmentally regulated expression of a novel 59-kda product of the major surface protease (msp or gp63) gene family of leishmania chagasi. | all species of leishmania express a major surface protease (msp or gp63) that facilitates the interactions of the parasite with its environment at several steps in its life cycle. the msp gene family in leishmania chagasi contains three classes of genes whose mrnas are differentially expressed during parasite growth. logarithmic phase (low infectivity) promastigotes express only 63-kda versions of msp, whereas stationary phase (high infectivity) promastigotes express both 63- and 59-kda msps. th ... | 1995 | 7721796 |
| a recombinant leishmania chagasi antigen that stimulates cellular immune responses in infected mice. | cellular immune mechanisms resulting in gamma interferon production are critical for protection against visceral leishmaniasis. antigens stimulating t-cell responses are likely present in the intracellular amastigote form of the parasite, since this is the form found in a mammalian host. to identify t-cell antigens of leishmania chagasi, the parasite causing south american visceral leishmaniasis, we used a double antibody-t-cell technique to screen an amastigote cdna library. one cdna selected ( ... | 1995 | 7729921 |
| familial aggregation of leishmania chagasi infection in northeastern brazil. | a sample of 1,604 individuals belonging to 243 nuclear families from an endemic area of visceral leishmaniasis (jacobina, bahia state, brazil) was studied to disclose the intrafamilial pattern of infection. significant father to offspring, mother to offspring, and sibling to sibling associations, in contrast a with nonsignificant father to mother association, clearly indicate a familial aggregation of the infection, with a strong suggestion of at least partial genetic involvement. | 1995 | 7741179 |
| intergenic regions between tandem gp63 genes influence the differential expression of gp63 rnas in leishmania chagasi promastigotes. | the major surface protease, gp63, of leishmania chagasi is encoded by 18 or more tandem msp genes that can be grouped into three classes on the basis of their unique 3'-untranslated sequences (3'-utrs) and their differential expression. rnas from the mspls occur predominantly during the logarithmic phase of promastigote growth in vitro, rnas from the mspss are present mainly in stationary phase, and rnas from mspcs occur throughout growth in culture. all three classes of gp63 genes are constitut ... | 1995 | 7744862 |
| sensitivity and specificity of a recombinant leishmania chagasi antigen in the serodiagnosis of visceral leishmaniasis. | | 1993 | 7802487 |
| preliminary observations on the diagnosis and transmissibility of canine visceral leishmaniasis in teresina, n.e. brazil. | a pilot group of 49 dogs and control groups from non-endemic areas were examined serologically for the presence of visceral leishmaniasis (vl) by direct agglutination test (dat), indirect immunofluorescence (ifat) enzyme-linked immunosorbent assay (elisa) and dot-elisa. results indicated that dat is less sensitive than the other assays and that serology with filter paper blood samples is less sensitive than with serum. promastigote infections were common in fed lutzomyia longipalpis taken from a ... | 1993 | 7802502 |
| granulocyte-macrophage colony-stimulating factor in combination with pentavalent antimony for the treatment of visceral leishmaniasis. | the efficacy of gm-csf was investigated in 20 neutropenic patients (< 1500 neutrophils/microliters) with acute visceral leishmaniasis due to leishmania chagasi. patients were randomized to receive either gm-csf, 5 micrograms/kg daily (intravenously or subcutaneously), or placebo for ten days, in combination with pentavalent antimony, 10-20 mg/kg daily for 20 days. neutrophil counts were significantly greater on days 5 and 10 of treatment in the gm-csf group compared with the placebo group (p < 0 ... | 1994 | 7875148 |
| response of leishmania chagasi promastigotes to oxidant stress. | at the onset of infection, leishmania promastigotes are phagocytized by mammalian macrophages. they must survive despite exposure to toxic oxidants such as hydrogen peroxide (h2o2) and superoxide (.o2-) generated during phagocytosis. we investigated the effects of these oxidants on leishmania chagasi promastigotes and promastigote mechanisms for oxidant resistance. according to spin trapping and electron paramagnetic resonance spectrometry, .o2- could be generated by exposure of promastigotes to ... | 1994 | 7927797 |
| cleavable complex formation in leishmania chagasi treated with anilinoacridines. | anilinoacridines have recently been found to possess antiparasitic activity toward leishmania, trypanosoma, and plasmodium species. these compounds have been examined for their ability to generate cleavable complex, the protein-associated dna lesion characteristic of topoisomerase ii involvement, in intact l. chagasi promastigotes. at cytotoxic concentrations, anilinoacridine compounds give cleavable complex in a whole cell assay which suggests that the drugs affect a nuclear topoisomerase ii in ... | 1994 | 7935616 |
| modulation of the low-affinity ige fc receptor (fc epsilon rii/cd23) by leishmania chagasi. | mature b lymphocytes and macrophages express low-affinity receptors for ige (cd23 or fc epsilon rii), a multifunctional molecule involved in ige regulation, b cell growth and antigen presentation. we studied the effect of the protozoan leishmania chagasi on cd23 expression using a model of early disease. murine and human b cells, b cell lines, and a macrophage cell line incubated in vitro with the promastigote (pm) form of l. chagasi showed a selective loss of cd23 expression as detected by mabs ... | 1994 | 7947462 |
| correlates of the peridomestic abundance of lutzomyia longipalpis (diptera: psychodidae) in amazonian brazil. | abundance of the sandfly lutzomyia longipalpis, the vector of leishmania chagasi, was surveyed using cdc light-suction traps in fifteen villages and 180 homesteads on marajó island, pará state, brazil. flies were most abundant in cultivated areas, secondary growth and open woodland, away from savanna grassland and forest. within homesteads, the abundance of flies in animal sheds was weakly associated with the number of hosts kept therein, and inversely related to the number elsewhere, both human ... | 1994 | 7949312 |
| development of leishmania chagasi (kinetoplastida: trypanosomatidae) in the second blood-meal of its vector lutzomyia longipalpis (diptera: psychodidae). | light and electron microscopy investigations were carried out to compare the development of leishmania chagasi in lutzomyia longipalpis females that took a second blood-meal and others that took a single blood-meal. the establishment of the parasite in the foregut and the thoracic midgut of the vector was not severely affected by the intake of the second blood-meal. at 3 days after the intake of the second blood-meal, a rapid increase in the proportion of metacyclic promastigotes detected in the ... | 1994 | 7971928 |
| saliva of lutzomyia longipalpis sibling species differs in its composition and capacity to enhance leishmaniasis. | leishmania donovani chagasi parasites, transmitted by sandflies of the lutzomyia longipalpis species complex, normally cause visceral leishmaniasis. however, in central america infections frequently result in cutaneous disease. we undertook experiments to investigate the possible influence of sandfly saliva on the course of infection. erythemas caused by feeding sandflies correlated well with the levels of the erythema-inducing peptide, maxadilan, in their saliva. saliva of brazilian flies was t ... | 1994 | 7972360 |
| characterization of t cell responses to purified leishmania antigens in subjects infected with leishmania chagasi. | t cell responses to lipophosphoglycan-associated protein (lpg-ap) and the rgp63 antigens were studied in subjects with either asymptomatic l. chagasi infection or cured visceral leishmaniasis. the [3h]-thymidine uptake of lymphocytes stimulated with lpg-ap and rgp63 (mean +/- sd) was 14275 +/- 5048 and 3523 +/- 1678 cpm, respectively, for subjects with asymptomatic l. chagasi infection and 20046 +/- 5102 and 5086 +/- 3500 cpm, respectively, for subjects cured of visceral leishmaniasis. the respo ... | 1994 | 8000341 |
| recombinant human granulocyte-macrophage colony-stimulating factor reverses neutropenia and reduces secondary infections in visceral leishmaniasis. | twenty-four patients with acute visceral leishmaniasis and leukopenia (< 1500 neutrophils/mm3) due to leishmania chagasi were studied, 4 in an open-label pilot study and 20 in a double-blind, placebo-controlled trial. patients received granulocyte-macrophage colony-stimulating factor (gm-csf), 5 micrograms/kg daily, or placebo for 10 days, plus 10-20 mg/kg pentavalent antimony daily for 20 days. in gm-csf recipients, neutrophil counts increased threefold and fourfold over baseline at 5 and 10 da ... | 1994 | 8035028 |
| acquisition of iron from transferrin and lactoferrin by the protozoan leishmania chagasi. | leishmania chagasi, the cause of south american visceral leishmaniasis, requires iron for its growth. however, the extent to which different iron sources can be utilized by the parasite is not known. to address this question, we studied acquisition of iron from lactoferrin and transferrin by the extracellular promastigote form of l. chagasi during growth in vitro. a promastigote growth medium based on minimal essential medium supplemented with iron-depleted serum supported promastigote growth on ... | 1994 | 8039896 |
| the subclinical form of experimental visceral leishmaniasis in dogs. | pathological aspects of a subclinical form of experimental canine leishmaniasis is reported here for the first time. fifteen mongrel dogs were used in the present study. eight dogs were infected and seven were used as control. four of the control dogs were inoculated with spleen cells from non-infected hamsters. the eight mongrel dogs inoculated intravenously with amastigotes forms of leishmania chagasi evolved for periods as long as 25 months without any clinical characteristic sign of classica ... | 1993 | 8107585 |
| development of eosinophilia in dogs intradermically inoculated with sand fly saliva and leishmania (leishmania) chagasi stationary-phase promastigotes. | salivary gland lysates of the sand fly lutzomia longipalpis have been shown to enhance the infectivity of leishmania in mice. as shown herein, the simultaneous inoculation of leishmania chagasi stationary-phase promastigotes and l. longipalpis salivary gland lysate by the intradermal route in a group of mongrel dogs induced a statistically significant eosinophilia, in relation to dogs inoculated with leishmania or with salivary gland lysate only. these dogs had no evidence of infection, in spite ... | 1993 | 8107586 |
| immunogold labeling and cerium cytochemistry of the enzyme ecto-5'-nucleotidase in promastigote forms of leishmania species. | we have applied both enzyme cytochemistry and immunological labeling techniques to characterize the enzyme 5'-nucleotidase (5'-nase), at the ultrastructural level, in promastigote forms of four leishmania species: leishmania amazonensis, leishmania mexicana, leishmania donovani and leishmania chagasi. the cerium phosphate staining was localized at the surface of the cell body, the flagellum and the flagellar pocket membranes of all the parasites studied. the immunogold labelling technique confir ... | 1993 | 8107602 |
| sequence diversity and organization of the msp gene family encoding gp63 of leishmania chagasi. | during in vitro growth leishmania chagasi promastigotes differentially express 3 classes of rnas encoding the major surface protease (msp) gp63 that can be distinguished by their unique 3' untranslated regions. here we show that the three classes (logarithmic-specific, stationary-specific and constitutively expressed) are encoded by a family of at least 4 tandem stationary genes (msps2, msps1, msps3 and msps5) followed by twelve or more logarithmic genes (mspl genes), one constitutive gene (mspc ... | 1993 | 8139613 |
| didelphis marsupialis, an important reservoir of trypanosoma (schizotrypanum) cruzi and leishmania (leishmania) chagasi in colombia. | the role of didelphis marsupialis as a reservoir of zoonotic hemoflagellates was examined in two ecologically distinct settings in colombia. while 72% (12 of 18) of the opossums collected in the tropical rain forest harbored trypanosoma cruzi, other mammals in the area had lower infection rates: 1.3% (proechymis semispinosus [spiny rat]; 13% tylomys mirae [climbing rat]; and 6% rattus rattus). trypanosoma cruzi isolates from d. marsupialis were similar to zymodeme 1 (z1), and two of four phenoty ... | 1994 | 8203703 |
| restoration of ifn-gamma production and lymphocyte proliferation in visceral leishmaniasis. | visceral leishmaniasis is associated with a marked depression of t cell responses, which has been characterized by the absence of il-2 and ifn-gamma production by lymphocytes on in vitro stimulation with leishmania ag. the aim of this study was to evaluate both the mechanism of these immunologic abnormalities and the restoration of in vitro t cell responses to leishmania ags. a total of 15 untreated visceral leishmaniasis patients were evaluated. although ifn-gamma and il-4 levels in the superna ... | 1994 | 8207220 |
| potential role for interleukin-10 in the immunosuppression associated with kala azar. | patients with acute kala azar are generally nonreactive in a number of immunologic assays, including t cell proliferation and generation of macrophage-activating cytokines, principally ifn-gamma, in response to leishmania antigens in vitro. to test for potential immunosuppressive factors, a series of t cell lines and clones were established from patients with acute kala azar, from patients after chemotherapy for kala azar, and from skin test-positive adults from the same endemic region. although ... | 1993 | 8254019 |
| molecular cloning, characterization, and expression in escherichia coli of iron superoxide dismutase cdna from leishmania donovani chagasi. | a cdna corresponding to superoxide dismutase (sod; ec 1.15.1.1.) was isolated from a leishmania donovani chagasi (l. d. chagasi) promastigote cdna library, using pcr with a set of primers derived from conserved amino acids of manganese sods (mnsods) and iron sods (fesods). comparison of the deduced amino acid sequences with previously reported sod amino acid sequences revealed that the l. d. chagasi 585-bp open reading frame had considerable homology with fesods and mnsods. the highest homology ... | 1994 | 8300222 |
| lutzomyia longipalpis is a species complex: genetic divergence and interspecific hybrid sterility among three populations. | the sand fly lutzomyia longipalpis is the vector of leishmania donovani chagasi in latin america. an analysis of genetic variability at 27 enzyme coding loci among three laboratory populations of lu. longipalpis revealed substantial genetic polymorphism. levels of genetic distance between all pairwise comparisons of colonies were very high, and consistent with those previously reported among separate species in the genus lutzomyia. between 7% and 22% of the loci studied were diagnostic for any t ... | 1993 | 8333579 |
| the effect of ongoing protein synthesis on the steady state levels of gp63 rnas in leishmania chagasi. | g63, the major surface glycoprotein of leishmania chagasi promastigotes, increases 11-fold in amount as promastigotes grow from logarithmic to stationary phase. transcripts from three different classes of gp63 genes are differentially expressed during this development (ramamoorthy, r., donelson, j. e., paetz, k. e., maybodi, m., roberts, s. p., and wilson, m. e. (1992) j. biol. chem. 267, 1888-1895). we studied the effect of protein synthesis inhibitors on gp63 mrnas. the steady state level of l ... | 1993 | 8340397 |