| visceral leishmaniasis in mice devoid of tumor necrosis factor and response to treatment. | tumor necrosis factor (tnf)-deficient mice were challenged with leishmania donovani to characterize tnf in the response of visceral intracellular infection to antileishmanial chemotherapy. in wild-type controls (i) liver infection peaked at week 2 and resolved, (ii) discrete liver granulomas developed at weeks 2 to 4 and involuted, and (iii) leishmanicidal responses to antimony (sb), amphotericin b (amb), and miltefosine were intact. in tnf knockout (ko) mice (i) initial liver infection was unre ... | 2000 | 11035737 |
| mononuclear cell recruitment, granuloma assembly, and response to treatment in experimental visceral leishmaniasis: intracellular adhesion molecule 1-dependent and -independent regulation. | in experimental visceral leishmaniasis, acquired resistance to intracellular leishmania donovani is th1 cell cytokine dependent and largely mediated by gamma interferon (ifn-gamma); the same response also permits conventional antimony (sb) chemotherapy to express its leishmanicidal effect. since the influxing blood monocyte (which utilizes endothelial cell icam-1 for adhesion and tissue entry) is a primary effector target cell for this cytokine mechanism, we tested the monocyte's role in host re ... | 2000 | 11035738 |
| suppression of posttreatment recurrence of experimental visceral leishmaniasis in t-cell-deficient mice by oral miltefosine. | t-cell-deficient nude mice infected with leishmania donovani were treated with miltefosine and then given either no treatment or intermittent miltefosine. intracellular visceral infection recurred in untreated mice but was suppressed by once- or twice-weekly oral administration of miltefosine. miltefosine may be useful as oral maintenance therapy for t-cell-deficient patients with visceral leishmaniasis. | 2000 | 11036063 |
| in vitro evaluation of newly synthesised [1,2,4]triazolo[1,5a]pyrimidine derivatives against trypanosoma cruzi, leishmania donovani and phytomonas staheli. | the antiprotozoal activity of newly synthesised compounds, all [1,2,4]triazolo [1,5a]pyrimidine derivatives, was tested against the protozoan parasites trypanosoma cruzi, leishmania donovani and phytotmonas staheli. six of these compounds significantly inhibited in vitro cell growth of the epimastigote forms of t. cruzi, and the promastigote forms of l. donovani and p. staheli. some of the compounds reached complete growth inhibition at 1 microg/ml for 48 h of parasite/drug interaction. none of ... | 2000 | 11048663 |
| resistance to arsenite modulates levels of alpha-tubulin and sensitivity to paclitaxel in leishmania donovani. | tubulin expression is known to alter due to drug resistance. differentiation of leishmania promastigotes into infectious amastigotes has been reported to be accompanied by differential tubulin gene expression. in this study, alpha-tubulin expression under various stages of differentiation was measured in an in vitro generated arsenite-resistant l. donovani strain. while levels of expression of alpha-tubulin were similar in wild type and resistant promastigotes, during conversion into axenic amas ... | 2000 | 11068817 |
| endogenous il-4 is necessary for effective drug therapy against visceral leishmaniasis. | it is well established that a fully competent immune response is required for the successful drug treatment of visceral leishmaniasis. however, recent studies have cast some doubt as to which elements of the immune response synergize with chemotherapeutic treatment. the role of the th2 response and il-4 in particular during visceral leishmaniasis awaits clarification. we, therefore, examined the effectiveness of sodium stibogluconate treatment on leishmania donovani infection in balb/c wild-type ... | 2000 | 11069076 |
| episomal and stable expression of the luciferase reporter gene for quantifying leishmania spp. infections in macrophages and in animal models. | we have expressed the reporter firefly luciferase gene (luc) in leishmania donovani and leishmania major either as part of episomal vectors or integrated into the parasite genome under the control of their respective ribosomal promoter regions. an excellent linear correlation between parasite number and luciferase activity was observed with all the transfectants. luc-expressing recombinant parasites were useful to monitor leishmania spp. infections in macrophages or in animal models. for prolong ... | 2000 | 11071276 |
| cellular effects of leishmanial tubulin inhibitors on l. donovani. | to aid our investigation of tubulin as an antileishmanial drug target, the effects of the mammalian antimicrotubule agents ansamitocin p3, taxol, and hemiasterlin on leishmania donovani promastigotes were described. these drugs affected the assembly of purified leishmanial tubulin and inhibited the growth of l. donovani promastigotes at micromolar concentrations. when promastigotes were treated with these agents, mitotic partitioning of nuclear dna and cytokinesis were usually inhibited. the spa ... | 2000 | 11071278 |
| the trypanosoma cruzi genome contains ion motive atpase genes which closely resemble leishmania proton pumps. | dna fragments homologous to members of the family of p-type ion-motive atpases were identified in trypanosoma cruzi by polymerase chain reaction (pcr) amplification. the sequence of one fragment, which closely resembled (87% identity) the tandemly linked proton pumps in leishmania, was used to characterize the h(+)-atpase genes in t. cruzi. the t. cruzi proton pump locus contains four tandemly repeated genes (tch1-4) separated by 1.1 kb intergenic regions. the nucleotide sequence of one cloned g ... | 2000 | 11077265 |
| ancistroealaines a and b, two new bioactive naphthylisoquinolines, and related naphthoic acids from ancistrocladus ealaensis. | two new 5,8'-coupled naphthylisoquinoline alkaloids, ancistroealaines a (1) and b (2), eleutherolic acid (3), and two naphthoic acids, ancistronaphthoic acid a (4) and b (5), have been isolated from ancistrocladus ealaensis. their structures were determined by spectroscopic, chemical, and chiroptical methods. ancistroealaine a (1) exhibited activity against leishmania donovani and trypanosoma cruzi in vitro. | 2000 | 11087584 |
| leishmania plasma membrane mg2+-atpase is a h+/k+-antiporter involved in glucose symport. studies with sealed ghosts and vesicles of opposite polarity. | experiments from other laboratories conducted with leishmania donovani promastigote cells had earlier indicated that the plasma membrane mg2+-atpase of the parasite is an extrusion pump for h+. taking advantage of the pellicular microtubular structure of the plasma membrane of the organism, we report procedures for obtaining sealed ghost and sealed everted vesicle of defined polarity. rapid influx of h+ into everted vesicles was found to be dependent on the simultaneous presence of atp (1 mm) an ... | 2001 | 11087746 |
| tubulin is hyperphosphorylated on serine and tyrosine residues in arsenite-resistant leishmania donovani promastigotes. | an arsenite-resistant strain of leishmania donovani was generated in vitro by the sequential exposure of a wild type strain to increasing concentrations of sodium m-arsenite. sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis of whole cell lysates of the two strains revealed that a protein band at the 55 kda position showed slower migration in the resistant samples. this band was identified as tubulin by immunoblotting, with both alpha- and beta-tubulin showing retarded migration ... | 2000 | 11097294 |
| visceral leishmaniasis in a dog from maryland. | visceral leishmaniasis is a zoonotic disease that can be transmitted from dogs to humans by a sand-fly vector. endemic cases of visceral leishmaniasis among dogs in oklahoma, texas, and ohio have been reported. recent reports of visceral leishmaniasis in foxhounds in the eastern coastal states has raised new concerns about the importance of this disease in the united states. | 2000 | 11110461 |
| novel intracellular sbv reducing activity correlates with antimony susceptibility in leishmania donovani. | the standard treatment of human visceral leishmaniasis involves the use of pentavalent antimony (sb(v)). its mechanism of action is unknown because of the limited information available about intracellular antimony metabolism and about the genes that regulate these processes. herein, flow injection-inductively coupled plasma mass spectrometry (icp-ms), flow injection hydride generation icp-ms, and ion chromatography icp-ms were used to measure antimony accumulation and intracellular metabolism in ... | 2001 | 11110784 |
| in vitro leishmanicidal activity of monomeric and dimeric naphthoquinones. | a series of monomeric and dimeric naphthoquinones with potential for treatment of leishmania infections was identified in vitro using both a direct cytotoxicity assay against extracellular promastigotes of leishmania donovani, l. infantum, l. enriettii, and l. major and a test against intracellular amastigote l. donovani residing within murine macrophages. several naphthoquinones proved to be active at concentrations in the microgram range (ec(50) 0.9-17.0 microg/ml). when tested against a panel ... | 2000 | 11114393 |
| immunization with a recombinant stage-regulated surface protein from leishmania donovani induces protection against visceral leishmaniasis. | vaccination against visceral leishmaniasis has received limited attention compared with cutaneous leishmaniasis, although the need for an effective vaccine against visceral leishmaniasis is pressing. in this study, we demonstrate for the first time that a recombinant stage-specific hydrophilic surface protein of leishmania donovani, recombinant hydrophilic acylated surface protein b1 (haspb1), is able to confer protection against experimental challenge. protection induced by rhaspb1 does not req ... | 2000 | 11120835 |
| antileishmanial activities of aphidicolin and its semisynthetic derivatives. | aphidicolin and a series of semisynthetic aphidicolan derivatives have been identified in in vitro tests as novel drugs with antiparasitic potential. all compounds have been tested against extracellular promastigotes of leishmania donovani, l. infantum, l. enriettii, and l. major and against intracellular amastigotes of l. donovani in murine macrophages. the compounds showed antileishmanial activity at concentrations in the microgram range (50% effective concentration [ec(50)] = 0.02 to 1.83 mic ... | 2001 | 11120979 |
| anti-leishmanial activity of neolignans from virola species and synthetic analogues. | surinamensin, a neolignan isolated from virola surinamensis, 3,4,5-trimethoxy-8-[2',6'-dimethoxy-4'-(e)-propenylphenoxy]-phenylpropane, a neolignan isolated from virola pavonis, and 25 of its synthetic analogues or correlated substances with ether linkages and their corresponding c-8 sulphur and nitrogen analogues, were tested for activity against leishmania donovani amastigotes and promastigotes in vitro. some were active against l. donovani promastigotes at 30 microm but inactive against intra ... | 2000 | 11130669 |
| visceral leishmaniasis control: a public health perspective. | visceral leishmaniasis (vl), also known as kala-azar, is a vector-borne disease caused by a protozoan of the leishmania donovani complex. a phlebotomine sandfly transmits the parasite from person to person or via an animal reservoir. vl is a severe, debilitating disease, characterized by prolonged fever, splenomegaly, hypergammaglobulinaemia and pancytopenia. patients become gradually ill over a period of a few months, and nearly always die if untreated. case-fatality ratios are high even in tre ... | 2000 | 11132368 |
| canine visceral leishmaniasis on margarita island (nueva esparta, venezuela). | the frequency of american visceral leishmaniasis affecting humans on margarita island, venezuela, has increased in recent years, and infected dogs appear to constitute the principal source of infection. elisa tests with leishmania donovani promastigotes and rk39 antigen from l. chagasi in serum from 541 dogs were positive in 33.1% and 21.6% of the samples, respectively. a second blood sample taken from 50 animals after 8-10 months revealed an increase from 24% to 40% of elisa positivity to both ... | 2000 | 11132371 |
| genetic heterogeneity of ribosomal internal transcribed spacer in clinical samples of leishmania donovani spotted on filter paper as revealed by single-strand conformation polymorphisms and sequencing. | a polymerase chain reaction and single-strand conformation polymorphism determination (pcr-sscp) was used to detect deoxyribonucleic acid sequence polymorphisms in the transcribed non-coding regions between the small and large sub-unit ribosomal ribonucleic acid (rrna) genes in leishmania donovani from 63 clinical samples collected in eastern sudan, between april 1997 and october 1998. specific leishmania primers were used to amplify the internal transcribed spacer (its) regions of l. donovani i ... | 2000 | 11132393 |
| role of pcr in diagnosis and prognosis of visceral leishmaniasis in patients coinfected with human immunodeficiency virus type 1. | a group of 76 consecutive human immunodeficiency virus (hiv)-positive patients with fever of unknown origin (n = 52) or fever associated with pulmonary diseases was evaluated in order to assess the usefulness of pcr with peripheral blood in the diagnosis and follow-up of visceral leishmaniasis. we identified 10 cases of visceral leishmaniasis among the 52 patients with fever of unknown origin. at the time of diagnosis, all were parasitemic by pcr with peripheral blood. during follow-up, a progre ... | 2001 | 11136800 |
| a phase iii trial of efficacy of the fml-vaccine against canine kala-azar in an endemic area of brazil (são gonçalo do amaranto, rn). | protection against canine kala-azar was investigated in naturally exposed dogs of an endemic area, vaccinated with the fucose mannose ligand (fml)-vaccine of leishmania donovani. a total of 97% of vaccinees were seropositive to fml and 100% showed intradermal reaction to l. donovani lysate, 7 months after vaccination. the absorbency values and size of intradermal reaction were both significantly higher in vaccinees than in controls (anova, p<0.0001). after 2 years, 92% (chi(2)=6.996; p<0.0025) p ... | 2000 | 11137242 |
| the hamster as a model of human visceral leishmaniasis: progressive disease and impaired generation of nitric oxide in the face of a prominent th1-like cytokine response. | active human visceral leishmaniasis (vl) is characterized by a progressive increase in visceral parasite burden, cachexia, massive splenomegaly, and hypergammaglobulinemia. in contrast, mice infected with leishmania donovani, the most commonly studied model of vl, do not develop overt, progressive disease. furthermore, mice control leishmania infection through the generation of no, an effector mechanism that does not have a clear role in human macrophage antimicrobial function. remarkably, infec ... | 2001 | 11160239 |
| chromosome structure and sequence organization between pathogenic and non-pathogenic leishmania spp. | we have used a chromosome fragmentation strategy based on systematic genomic insertions of the rare cutting yeast i-scei endonuclease to assess structure and sequence organization of homologous chromosomes between evolutionary divergent pathogenic and non-pathogenic leishmania species. this method was combined to physical mapping and hybridization studies using a number of specific chromosomal markers as probes. our studies have concentrated on two different chromosomes of leishmania major (l. m ... | 2000 | 11163446 |
| latex agglutination test for the detection of urinary antigens in visceral leishmaniasis. | this paper describes a new latex agglutination test ('katex') for the detection of leishmanial antigen in the urine of patients with visceral leishmaniasis. in preliminary laboratory trials, using urine collected from well-defined cases and controls from brazil, yemen and nepal, the test had 100% specificity and a sensitivity between 68 and 100%. when used in a time-course experiment in cotton rats infected with leishmania donovani, the test became positive 1 week after inoculation and antigen l ... | 2001 | 11164745 |
| tetracycline regulated gene expression in leishmania donovani. | the prokaryotic tetracycline-responsive repressor/operator system has proven to be useful for studying the function of essential genes and the expression of toxic gene products in a number of organisms, including trypanosoma brucei. we report here the adaptation of this system for use in leishmania. the inducible promoter construct contains a bleomycin resistance-luciferase fusion (ble-luc) gene driven by an rrna promoter with two copies of the teto sequence inserted two nucleotides upstream of ... | 2001 | 11166387 |
| circulating levels of stnfr and discrepancy between cytotoxicity and immunoreactivity of tnf-alpha in patients with visceral leishmaniasis. | to study the influence of soluble tumour necrosis factor (tnf) receptors (stnfr) on bioactivity and immunoreactivity of tnf-alpha in patients with visceral leishmaniasis (kala-azar) and to examine the association between circulating levels of stnfr type i and type ii with clinical manifestations of the disease. | 2000 | 11168034 |
| macrophage heterogeneity, antigen presentation, and membrane fluidity: implications in visceral leishmaniasis. | morphological and functional heterogeneity of the splenic macrophage (m phi) population was studied in leishmania donovani (ld) infected balb/c mice. on a discontinuous percoll gradient two distinct m phi populations were separated. they differed significantly in size as evident from scanning electron microscopy (sem). morphologically, the bigger m phi (lm) showed surface projections, whereas the smaller m phi (sm) was round. as regards the antigen-presenting abilities, the lm of infected animal ... | 2001 | 11169214 |
| immunomodulatory role of interleukin-10 in visceral leishmaniasis: defective activation of protein kinase c-mediated signal transduction events. | leishmania donovani, an intracellular protozoan parasite, challenges host defense mechanisms by impairing the signal transduction of macrophages. in this study we investigated whether interleukin-10 (il-10)-mediated alteration of signaling events in a murine model of visceral leishmaniasis is associated with macrophage deactivation. primary in vitro cultures of macrophages infected with leishmanial parasites markedly elevated the endogenous release of il-10. treatment with either l. donovani or ... | 2001 | 11179319 |
| treatment of visceral leishmaniasis (kala-azar): a decade of progress and future approaches. | in 1990, there was essentially one treatment regimen in use for visceral leishmaniasis (kala-azar) around the world: 20 to 28 days of daily injections of pentavalent antimony (sb). during the past 10 years, however, new agents have been tested alone or in combination, in more than 50 studies carried out worldwide. this renewed clinical effort was spurred by a variety of factors, including the emergence of large-scale sb unresponsiveness in india, where up to one-half of the world's cases of kala ... | 2000 | 11179920 |
| overexpression, purification, and characterization of s-adenosylhomocysteine hydrolase from leishmania donovani. | the gene encoding s-adenosylhomocysteine (adohcy) hydrolase in leishmania donovani was subcloned into an expression vector (pprok-1) and expressed in escherichia coli. recombinant l. donovani adohcy hydrolase was then purified from cell-free extracts of e. coli using three chromatographic steps (deae-cellulose chromatofocusing, sephacryl s-300 gel filtration, and q-sepharose ion exchange). the purified recombinant l. donovani enzyme exists as a tetramer with a molecular weight of approximately 4 ... | 2000 | 11185563 |
| calcium-induced conformational changes in leishmania infantum kinetoplastid membrane protein-11. | total-reflection x-ray fluorescence has been used to study whether the leishmania infantum kinetoplastid membrane protein-11 is a ca2+-binding protein. the 108 amino acid helix-loop-helix protein has the loop region located between residues 45 and 57, having similarity to the ef-hand motifs. in particular, the sequence alignment of the putative motif revealed the existence of 67% similarity and 33% identity with the ef-hand of the plasmodia-specific 40-kda protein from physarum polycephalum. to ... | 2001 | 11191218 |
| interaction of ascorbate and alpha-tocopherol enhances antioxidant reserve of erythrocytes during anemia in visceral leishmaniasis. | visceral leishmaniasis (v.l.) is associated with enhanced lipid peroxidation along with impaired function of antioxidant defense system in erythrocytes. the effect of chronic treatment with ascorbate and alpha-tocopherol was studied on erythrocytes in hamsters infected with leishmania donovani. combination treatment with both antioxidants proved to be a potential suppressor of lipid hydroperoxide formation as well as hypotonic osmotic lysis during the leishmanial infection. positive correlations ... | 2000 | 11191625 |
| targeting of liposomal andrographolide to l. donovani-infected macrophages in vivo. | despite the rapid development in medicinal and pharmaceutical technology, the targeting of drugs to phagocytic cells in macrophage-related diseases still remains a major unsolved problem. by using the mannosyl-fucosyl receptors on macrophages, attempts were made to target antileishmanial drugs encapsulated in mannosylated or fucosylated liposomes to treat experimental leishmaniasis in the hamster model. mannosylated liposomes were found to be more potent in delivering antileishmanial drugs to ph ... | 2000 | 11195427 |
| gp63 gene polymorphism and population structure of leishmania donovani complex: influence of the host selection pressure? | the gp63 encoding genes were characterized by pcr-rflp in 35 isolates representative of the leishmania donovani complex (l. infantum, l. donovani, l. archibaldi and l. chagasi), with special attention to mediterranean l. infantum from different geographical origins, and in separate groups from old world leishmania (l. major, l. tropica and l. aethiopica). the aim was to evaluate how the possible selective pressure by the host on these important surface proteins would influence structuring of our ... | 2001 | 11197761 |
| relevance of direct agglutination test in seroepidemiological survey of kala-azar in epidemic foci of bihar. | the performance of direct agglutination test (dat) was evaluated under field conditions in three endemic districts of bihar. in three villages of these districts, 197 households were surveyed with a population of 1167 individuals. out of 1167 individuals, 603 were clinically examined for vl and blood samples of each examined individual were collected for dat. the proportion of dat positivity in both males (32.33%) and females (32.94%) was statistically not significant (p > 0.05). the proportion ... | 2000 | 11198396 |
| leishmania donovani: intraspecific polymorphisms of sudanese isolates revealed by pcr-based analyses and dna sequencing. | four polymerase chain reaction (pcr)-based approaches were used to analyze diversity within 23 sudanese isolates of leishmania donovani. methods compared were fingerprinting with single nonspecific primers, restriction analysis of the amplified ribosomal internal transcribed spacer (its) locus, single-stranded conformation polymorphism (sscp), and sequencing of the its region. when pcr fingerprinting and restriction analysis of its were applied, highly similar fragment patterns were observed for ... | 2001 | 11207112 |
| general suppression of macrophage gene expression during leishmania donovani infection. | within the mammalian host, leishmania donovani is an obligatory intracellular protozoan that resides and multiplies exclusively in the phagolysosomes of macrophages. the outcome of this infection is governed by the interaction between leishmania and macrophage molecules that ultimately effect the expression of genes within both cells. to explore the effect of this intracellular infection on macrophage gene expression, a cdna expression array analysis was performed to compare gene expression prof ... | 2001 | 11207299 |
| impaired recruitment of the small gtpase rab7 correlates with the inhibition of phagosome maturation by leishmania donovani promastigotes. | we have shown recently that one of the survival strategies used by leishmania donovani promastigotes during the establishment of infection in macrophages consists in inhibiting phagosome-endosome fusion. this inhibition requires the expression of lipophosphoglycan (lpg), the predominant surface glycoconjugate of promastigotes, as parasites expressing truncated forms of lpg reside in phagosomes that fuse extensively with endocytic organelles. in the present study, we developed a single-organelle ... | 1999 | 11207538 |
| leishmania promastigotes require lipophosphoglycan to actively modulate the fusion properties of phagosomes at an early step of phagocytosis. | the lipophosphoglycan (lpg) of leishmania promastigotes plays key roles in parasite survival in both insect and mammalian hosts. evidence suggests that lpg decreases phagosome fusion properties at the onset of infection in macrophages. the mechanisms of action of this molecule are, however, poorly understood. in the present study, we used a panoply of leishmania mutants displaying modified lpg structures to determine more precisely how lpg modulates phagosome-endosome fusion. using an in vivo fu ... | 2000 | 11207568 |
| macrophage subsets harbouring leishmania donovani in spleens of infected balb/c mice: localization and characterization. | the purpose of the current study was to characterize parasite-containing cells located in spleens of balb/c mice infected with leishmania donovani. in particular, expression of mhc class ii molecules by these cells was examined to determine whether they could potentially act as cells capable of immunostimulating leishmania-reactive cd4+ t lymphocytes. to this end, an immunohistological analysis of spleens taken at various time points after infection was undertaken. using this approach, we observ ... | 2000 | 11207597 |
| selective impairment of protein kinase c isotypes in murine macrophage by leishmania donovani. | leishmania donovani, an obligate intracellular parasite resides and multiplies within macrophage of the reticuloendothelial system. the intracellular signalling mechanism involved in the impaired oxidative response in leishmaniasis has not yet been clearly established. generation of superoxide anion (o2-) is supposed to be the first line of host defence during microbial invasion. we found a substantial inhibition of superoxide anion generation in parasitized macrophages, which was just the rever ... | 2001 | 11216863 |
| terpenoids from guarea rhophalocarpa. | four new terpenes including, two sandaracopimaradiene diterpenoids, ent-8(14),15-sandaracopimaradiene-2alpha,18-diol, and ent8(14),15-sandaracopimaradiene-2beta,18-diol, and two lanostane triterpenoids, 23-hydroxy-5alpha-lanosta 7,9(11),24-triene-3-one, and 5alpha-lanosta-7,9(11),24-triene-3alpha,23-diol, were isolated from the methanolic extract prepared from the leaves of g. rhopalocarpa together with the known steroid stigmasterol and the coumarin, scopoletin. the isolates showed weak antipro ... | 2001 | 11219815 |
| speciation of antimony(iii) and antimony(v) in cell extracts by anion chromatography/inductively coupled plasma mass spectrometry. | an analytical method for the separation and quantification of sb(iii) and sb(v) using anion chromatography with icp-ms is presented. the optimum conditions for the separation of the antimony species were established with 15 mmol/l nitric acid at ph 6 as eluent system on a prp-x100 column. the retention times for antimony(v) and antimony(iii) were 85 s and 300 s with detection limits of 0.06 microg/l and 0.29 microg/l, respectively. the proposed method was applied to cell extracts of leishmania d ... | 2000 | 11220833 |
| 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 |
| leishmania virulence: it's a knock out! | | 2001 | 11228002 |
| more panantigens in leishmania. | | 2001 | 11228008 |
| immunogenicity and safety of autoclaved leishmania major plus bcg vaccine in healthy sudanese volunteers. | in a longitudinal study in the epidemiology of leishmania donovani infection in an endemic focus in eastern sudan, we observed that previous exposure or infection with leishmania major appeared to protect against visceral leishmaniasis caused by l. donovani. we therefore conducted a study to test the safety and immunogenicity of a vaccine consisting of autoclaved l. major (alm) plus bcg in inducing protection in vaccinated individuals. leishmanin-negative healthy sudanese volunteers were enrolle ... | 2001 | 11228382 |
| development of a species-specific pcr assay for detection of leishmania donovani in clinical samples from patients with kala-azar and post-kala-azar dermal leishmaniasis. | we have developed a pcr assay that is capable of amplifying kinetoplast dna (kdna) of leishmania donovani in a species-specific manner among old world leishmanias. with indian strains and isolates of l. donovani the assay was sensitive enough to detect kdna in an amount equivalent to a single parasite or less. the extreme sensitivity of the assay was reflected in its ability to detect parasite dna from small volumes of peripheral blood of patients with kala-azar (ka) and from skin lesions from p ... | 2001 | 11230394 |
| hepatitis b and c viral infections in indian kala-azar patients receiving injectable anti-leishmanial drugs: a community-based study. | human immunodeficiency virus (hiv) and hepatitis b and hepatitis c viruses have emerged as major blood-borne infections. several cases of infections through the use of unsterile injection needles also are on record. kala-azar, or visceral leishmaniasis, is a hemoparasitic disease caused by leishmania donovani. all the anti-kala-azar medications require multiple intramuscular injections of the anti-leishmanial drugs. to find whether these patients were at higher risk of contracting blood-borne in ... | 2000 | 11231183 |
| successful therapy of lethal murine visceral leishmaniasis with cystatin involves up-regulation of nitric oxide and a favorable t cell response. | the virulence of leishmania donovani in mammals depends at least in part on cysteine proteases because they play a key role in cd4(+) t cell differentiation. a 6-fold increase in no production was observed with 0.5 microm chicken cystatin, a natural cysteine protease inhibitor, in ifn-gamma-activated macrophages. in a 45-day balb/c mouse model of visceral leishmaniasis, complete elimination of spleen parasite burden was achieved by cystatin in synergistic activation with a suboptimal dose of ifn ... | 2001 | 11238649 |
| leishmaniasis diagnosed by liver biopsy: management of two atypical cases. | two patients presenting with pyrexia of unknown origin were diagnosed as having visceral leishmaniasis based on the presence of leishmania donovani bodies in liver tissue. of particular interest is that these two case reports suggest that in patients with pyrexia of unknown origin, a liver biopsy for l. donovani bodies should be considered even when several months have passed since leaving an endemic area, when splenomegaly is absent, when bone marrow examination and serology are not diagnostic, ... | 2001 | 11246361 |
| phospholipase d (pld) is present in leishmania donovani and its activity increases in response to acute osmotic stress. | we report here that the signaling molecule phospholipase d (pld) is present in the parasitic protozoan leishmania donovani. in vitro enzymatic activity is dependent on ca2+ and mg2+ ions, its basal activity is stimulated by phosphatidyl-inositol-4,5-bisphosphate (pip2) and its ph optima are ph 8.0 and ph 6.0. pld activity increases 3-fold about 5 min after an abrupt decrease in osmolality from 317 mosm (isosmotic) to 155 mosm and increases 1.5-fold in response to an abrupt increase in osmolality ... | 2001 | 11249184 |
| characterization of the a2-a2rel gene cluster in leishmania donovani: involvement of a2 in visceralization during infection. | the a2 gene family is present in leishmania donovani, which causes fatal visceral leishmaniasis in human patients, but is not present in leishmania major, which causes cutaneous leishmaniasis infections. the a2 genes in l. donovani are stage specific and are expressed at high levels in the amastigote stage in the mammalian host, but are not expressed in the promastigote stage in the insect sandfly vector. the a2 genes are tandem repeated with a distinct gene family termed the a2rel genes. in ord ... | 2001 | 11251814 |
| diagnosing visceral leishmaniasis with the recombinant k39 strip test: experience from the sudan. | we compared a strip test employing recombinant k39 (rk39) antigen and protein a/colloidal gold as read-out agents with the rk39 elisa for igm and igg antibodies and the direct agglutination test (dat) using 55 sera from patients with parasitologically confirmed visceral leishmaniasis (vl). the rk39 strip test was positive in 37/55 (67%), the dat in 50/55 (91%) at > or = 1 : 1600 cut-off value and in 47/55 (85%) at > or = 1 : 6400 cut-off value. the rk39-elisa gave positive igg results for all se ... | 2001 | 11251906 |
| pediatric visceral leishmaniasis in austria: diagnostic difficulties in a non-endemic region. | visceral leishmaniasis is usually fatal if left untreated. in europe it is mainly caused by leishmania infantum which is endemic in the whole mediterranean region. while visceral leishmaniasis classically affects children, adults increasingly suffer infections in regions which are known to be endemic for hiv. nowadays up to 70% of the patients with visceral leishmaniasis in southern europe are hiv-infected adults. the diagnosis is known to be especially difficult to establish in this group of pa ... | 2001 | 11253734 |
| liposomal amphotericin b. | | 2001 | 11253992 |
| in vivo monitoring of intracellular atp levels in leishmania donovani promastigotes as a rapid method to screen drugs targeting bioenergetic metabolism. | a method for the rapid screening of drugs targeting the bioenergetic metabolism of leishmania spp. was developed. the system is based on the monitoring of changes in the intracellular atp levels of leishmania donovani promastigotes that occur in vivo, as assessed by the luminescence produced by parasites transfected with a cytoplasmic form of phothinus pyralis luciferase and incubated with free-membrane permeable d-luciferin analogue d-luciferin-[1-(4,5-dimethoxy-2-nitrophenyl) ethyl ester]. a s ... | 2001 | 11257025 |
| secretory and endocytic pathways converge in a dynamic endosomal system in a primitive protozoan. | leishmania are a group of primitive eukaryotic trypanosomatid protozoa that are apically polarized with a flagellum at their anterior end. surrounding the base of the flagellum is the flagellar reservoir that constitutes the site for endocytosis and exocytosis in these organisms. in the present study, we define a novel multivesicular tubular compartment involved in the intracellular trafficking of macromolecules in leishmania. this dynamic structure appears to subtend the flagellar reservoir and ... | 2001 | 11260523 |
| immunomodulatory principles of pelargonium sidoides. | extracts and isolated constituents (coumarins and phenols) of pelargonium sidoides dc, a plant species used in folk medicine by the southern african native population, were evaluated for their effects on nonspecific immune functions. although this herbal medicine is also successfully employed in modern phytotherapy in europe to cure infectious diseases of the respiratory tract, the scientific basis of its remedial effects is still unclear. thus, functional bioassays including an in vitro model f ... | 2001 | 11268110 |
| in vitro leishmanicidal activity of naturally occurring chalcones. | a variety of chalcones have been shown to exhibit activity against leishmania parasites. in contrast to synthetic or semisynthetic chalcones, only a few plant-derived compounds have been investigated. to provide a scientific rational for the antiprotozoal potency of plants used in ethnomedicine and containing chalcones, and in the search for new antiprotozoal drugs, we have carried out a primary screening for in vitro leishmanicidal activity of 20 chalcones isolated from plants. the compounds we ... | 2001 | 11268116 |
| green fluorescent protein-tagged leishmania in phlebotomine sand flies. | in this work we have used for the first time green fluorescent protein (gfp) tagged cells of the human parasite leishmania donovani to observe its development in the gut of phlebotomine sand flies. low numbers of gfp-tagged l. donovani were more easily detected than nontagged leishmania, suggesting that gfp-tagged leishmania could be used to efficiently study the biology of leishmania in their vectors, and open the possibility of using nonaxenic flies. using this method, we found that gfp-tagged ... | 2001 | 11268689 |
| lack of abundance of cytoplasmic cyclosporin a-binding protein renders free-living leishmania donovani resistant to cyclosporin a. | the majority of the effects of cyclosporin a (csa) on cells is caused by the inhibition of phosphatase activity of calcineurin (cn) by the cyclophilin a (cypa)-csa complex formed in the cytoplasm. although csa inhibits the proliferation of a large number of parasites, not all are susceptible. the presence of structurally altered cypa with lower affinity for csa had been suggested to be the cause of resistance. we report here the identification and cloning of a high affinity csa-binding protein ( ... | 2001 | 11278494 |
| flotillin-1-enriched lipid raft domains accumulate on maturing phagosomes. | flotillin-1 was recently shown to be enriched on detergent-resistant domains of the plasma membrane called lipid rafts. these rafts, enriched in sphingolipids and cholesterol, sequester certain proteins while excluding others. lipid rafts have been implicated in numerous cellular processes including signal transduction, membrane trafficking, and molecular sorting. in this study, we demonstrate both morphologically and biochemically that lipid rafts are present on phagosomes. these structures are ... | 2001 | 11279173 |
| interleukin-13 in iranian patients with visceral leishmaniasis: relationship to other th2 and th1 cytokines. | the role of interleukin (il)-13, a th2 cytokine sharing many of the features of il-4, has not previously been examined in patients with visceral leishmaniasis (vl). we examined sera from iranian patients with vl caused by leishmania infantum. serum il-13 was detected in 50% (22/44) of patients with active primary disease. in comparison, il-10 was detected in 79.5% (35/44), interferon gamma (ifn gamma) in 38.5% (17/44), and il-4 in only 5% (2/44) of these patients. with few exceptions all 3 cytok ... | 2001 | 11280075 |
| mapping of the antigenic determinants of the t. cruzi kinetoplastid membrane protein-11. identification of a linear epitope specifically recognized by human chagasic sera. | the high variability among strains and isolates of trypanosoma cruzi and the existence of shared antigenic determinants with other pathogens, particularly with members of the leishmania genus make difficult the specific diagnosis of chagas' disease. the data reported in this paper show that the t. cruzi kmp11 protein is an immunodominant antigen highly recognized by the sera from chagasic and leishmaniasis patients. by the use of amino- and carboxyl-terminal truncated kmp11 recombinant proteins ... | 2001 | 11298135 |
| leishmania donovani-induced macrophages cyclooxygenase-2 and prostaglandin e2 synthesis. | prostaglandin e2 (pge2) secretion during leishmania infection has been reported. however, the signalling mechanisms mediating this response are not well understood. since cyclooxygenase-2 (cox-2) and cytosolic phospholipase a2 (cpla2) are involved in pge2 synthesis in response to various stimuli, the implication of these enzymes was evaluated in leishmania-infected phorbol myristate acetate-differentiated u937 human monocytic cell line. time-course experiments showed that pge2 synthesis increase ... | 2001 | 11298294 |
| cd95 is required for the early control of parasite burden in the liver of leishmania donovani-infected mice. | in this study we show an increased incidence of t cell apoptosis in the liver and spleen of mice infected with leishmania donovani. t cells from l. donovani-infected mice were found to be increasingly susceptible to cd95-mediated apoptosis in vitro, compared to controls. to test if suboptimal t cell function resulting from cd95-mediated apoptosis contributes to sustained parasite burden in l. donovani parasitized mice, b6.gld mice (lacking functional cd95 ligand) were infected with l. donovani. ... | 2001 | 11298345 |
| seasonal and nocturnal landing/biting behaviour of phlebotomus argentipes (diptera: psychodidae). | the nocturnal activity of phlebotomus argentipes (diptera: psychodidae), the main vector of leishmania donovani in india, was studied throughout a year, with monthly collections, between 18.00 and 06.00 hours, of the sandflies landing on 15 humans and 15 cows in the village of bahapur, patna district. the cattle appeared to be better as bait, since more than five female p. argentipes were caught on them for each one caught on the human bait. overall, although p. argentipes were caught during eac ... | 2001 | 11299126 |
| bisphosphonates inhibit the growth of trypanosoma brucei, trypanosoma cruzi, leishmania donovani, toxoplasma gondii, and plasmodium falciparum: a potential route to chemotherapy. | we have investigated the effects in vitro of a series of bisphosphonates on the proliferation of trypanosoma cruzi, trypanosoma brucei rhodesiense, leishmania donovani, toxoplasma gondii, and plasmodium falciparum. the results show that nitrogen-containing bisphosphonates of the type used in bone resorption therapy have significant activity against parasites, with the aromatic species having in some cases nanomolar or low-micromolar ic(50) activity values against parasite replication (e.g. o-ris ... | 2001 | 11300872 |
| a possible role of bats as a blood source for the leishmania vector lutzomyia longipalpis (diptera: psychodidae). | some evidence suggests that bats may provide an alternative blood source for lutzomyia longipalpis, the main vector of american visceral leishmaniasis. feeding trials were conducted to determine whether l. longipalpis feeds on captive bats. the high feeding success indicated that l. longipalpis is capable of feeding on at least four species of bats. implications for the epidemiology of leishmaniases are discussed. | 2000 | 11304062 |
| leishmania immune adherence reaction in vertebrates. | in normal human blood, c3-opsonized leishmania promastigotes immune adhere to erythrocytes, a mechanism believed to enhance their clearance from blood and phagocytosis. given the potential importance of this reaction in host defence against infection, the promastigote-erythrocyte interaction was studied in blood of individuals from one avian and 12 mammalian genera; [111in]-labelled promastigotes were found to bind only to primate erythrocytes. nevertheless, previous experiments coincubating pla ... | 2001 | 11309136 |
| synthesis of 2-substituted trifluoromethylquinolines for the evaluation of leishmanicidal activity. | the synthesis of 2-substituted-trifluoromethylquinolines from aniline, trifluoromethylanilines, 3-aminoquinoline and trifluoromethylquinaldines is reported. in vitro antileishmanial evaluation of 2-alkyl, 2-alkenyl and 2-epoxypropyl-trifluoromethylquinolines is presented. | 2001 | 11310679 |
| vaccination of balb/c mice against experimental visceral leishmaniasis with the gp36 glycoprotein antigen of leishmania donovani. | leishmania donovani gp36 glycoprotein is the main antigen of the fml fucose mannose ligand (fml) complex specifically recognized by sera of kala-azar human patients. the gp36 was isolated by chemical elution + sonication and used for balb/c mouse vaccination in combination with saponin, by the s.c. route, inducing a strong and specific protective effect against experimental visceral leishmaniasis shown by the increase of: specific igg antibodies (82.6%), mainly igg2a, the delayed type of hyperse ... | 2001 | 11312005 |
| protection against leishmania donovani infection by dna vaccination: increased dna vaccination efficiency through inhibiting the cellular p53 response. | dna-vaccination holds great promise for the future of vaccine development against infectious diseases, especially in developing countries. we therefore investigated the possibility of using dna-vaccination against leishmania donovani infection with the a2 virulence gene and whether inhibiting the cellular p53 response could increase the effectiveness of the a2 dna vaccine. p53, also known as the guardian of the genome, is activated following dna transfection and has pleotropic effects on cells, ... | 2001 | 11312013 |
| adaptation of leishmania cells to in vitro culture results in a more efficient reduction and transport of biopterin. | leishmania major and leishmania donovani cells freshly isolated from infected animals divided slowly as axenic promastigotes but the addition of biopterin in the culture medium greatly enhanced their growth. however, when cells were subjected to serial passages and adapted to culture, this growth-promoting effect of biopterin was no longer observed. genetic analysis of these culture-adapted leishmania cells demonstrated that the genes coding for the pterin reductase ptr1 or for the biopterin tra ... | 2001 | 11312578 |
| genetic typing and phylogeny of the leishmania donovani complex by restriction analysis of pcr amplified gp63 intergenic regions. | protozoan parasites of the leishmania donovani complex (l. donovani, l. infantum/l. chagasi) are causative agents of visceral leishmaniasis. to understand phylogeny and taxonomy within this group better we have developed 2 new polymerase chain reaction-linked restriction fragment length polymorphism (pcr-rflp) analyses of the major surface protease (msp or gp63) intergenic (itg) regions. we have named this approach msp intergenic region rflp typing (mirt). one intergenic region lies between the ... | 2001 | 11315172 |
| novel inhibitors of leishmanial dihydrofolate reductase. | the program dock3.5 was used to search the cambridge structural database for novel inhibitors of leishmanial dihydrofolate reductase. a number of compounds were obtained and screened against the enzyme and against the intact parasite leishmania donovani and the related organisms trypanosoma brucei and trypanosoma cruzi. the compounds screened showed weak activity in both the enzyme assays and the in vitro assays. | 2001 | 11327604 |
| characterisation of the gene encoding type ii dna topoisomerase from leishmania donovani: a key molecular target in antileishmanial therapy. | the gene encoding type ii dna topoisomerase from the kinetoplastid hemoflagellated protozoan parasite leishmania donovani (ldtop2) was isolated from a genomic dna library of this parasite. dna sequence analysis revealed an orf of 3711 bp encoding a putative protein of 1236 amino acids with no introns. the deduced amino acid sequence of ldtop2 showed strong homologies to top2 sequences from other kinetoplastids, namely crithidia and trypanosoma spp. with estimated identities of 86 and 68%, respec ... | 2001 | 11328867 |
| fmlp receptor stimulated activation of macrophage: its effect on killing of intracellular leishmania donovani. | the fmlp receptor of peritoneal macrophages stimulated by fmlp grafted liposomes as ligand, was analysed and compared with respective controls for its ability to promote killing of intracellular leishmania parasites. fmlp grafted liposomes show greater efficacy in killing intracellular l. donovani (mhom/in/1983/ag83) parasites in a time dependent manner than free fmlp. fmlp grafted liposomes also release more active oxygen intermediates and reactive nitrogen intermediates (o2-, h2o2, no) than fr ... | 2000 | 11332597 |
| optimisation of an elisa for the serodiagnosis of visceral leishmaniasis using in vitro derived promastigote antigens. | an antibody detection elisa was developed for diagnosis of visceral leishmaniasis. antigens released by leishmania donovani promastigotes into a protein-free medium were used. sds-page analysis has indicated that ld-esm contain several protein antigens. titration and chequer-board analyses were performed to optimise the assay protocol. optimal results were obtained when antigen (50 microg/ml) was coated with pbs-methyl glyoxal buffer, and wells blocked with 0.5% casein. a serum dilution of 1:500 ... | 2001 | 11334970 |
| successful vaccination against leishmania donovani infection in indian langur using alum-precipitated autoclaved leishmania major with bcg. | autoclaved leishmania major (alm) along with bcg, presently undergoing phase ii clinical trial by who for its vaccine potential against cutaneous leishmaniasis, has been successfully evaluated in single and triple dose schedules against l. donovani in indian langurs (presbytis entellus). encouraged with the results, another formulation alum-precipitated alm (provided by who) along with bcg has been evaluated in this system. eight monkeys were vaccinated with alum-precipitated alm + bcg (1 mg of ... | 2001 | 11348715 |
| activities of hexadecylphosphocholine (miltefosine), ambisome, and sodium stibogluconate (pentostam) against leishmania donovani in immunodeficient scid mice. | in both scid and balb/c mouse-leishmania donovani models, hexadecyphosphocholine (miltefosine) and ambisome had similar levels of activity. in contrast, sodium stibogluconate (pentostam) was significantly less active against l. donovani in scid mice than in balb/c mice. the in vitro anti-leishmanial activity of miltefosine was similar in peritoneal macrophages derived from both scid and balb/c mice, whereas pentostam and ambisome were significantly more active in the latter. | 2001 | 11353640 |
| point mutations in a nucleoside transporter gene from leishmania donovani confer drug resistance and alter substrate selectivity. | leishmania parasites lack a purine biosynthetic pathway and depend on surface nucleoside and nucleobase transporters to provide them with host purines. leishmania donovani possess two closely related genes that encode high affinity adenosine-pyrimidine nucleoside transporters ldnt1.1 and ldnt1.2 and that transport the toxic adenosine analog tubercidin in addition to the natural substrates. in this study, we have characterized a drug-resistant clonal mutant of l. donovani (tuba5) that is deficien ... | 2001 | 11353834 |
| leishmania species, drug unresponsiveness and visceral leishmaniasis in bihar, india. | sixteen isolates obtained, in january 1998-december 1999, from splenic aspirates from sodium stibogluconate-resistant cases of visceral leishmaniasis (vl; indian kala-azar) and drawn from different districts of bihar (india) were identified as leishmania donovani. by isoenzyme analysis, all the strains were found identical to the who reference strain l. donovani mon-2 and differed from l. tropica mon-5. this study suggested that resistant cases of vl in bihar were caused by l. donovani and not b ... | 2001 | 11355558 |
| isoenzyme characterization of leishmania isolates from lebanon and syria. | leishmania parasites were isolated from 22 lebanese and 5 syrian patients with active skin lesions for whom the diagnosis was confirmed by histopathological examination. the isolates were characterized by starch gel electrophoresis and analysis of 13 enzyme systems. eight old-world reference strains were used for comparison. one syrian isolate belonged to leishmania major, and four syrian and two lebanese to leishmania tropica. contrary to expectations, the majority of lebanese isolates were rel ... | 2000 | 11357993 |
| inhibition of hiv-1-mediated syncytium formation and virus replication by the lipophosphoglycan from leishmania donovani is due to an effect on early events in the virus life cycle. | previous findings have indicated that the major surface molecule of leishmania, lipophosphoglycan (lpg), could abrogate hiv-1-induced syncytium formation and virus replication. in the present work, we were interested in characterizing this inhibitory process. data from a new luciferase-based semiquantitative assay for syncytium formation, relying on the coincubation of a t-cell line containing an hiv-1 ltr-driven luciferase construct with a cell line chronically infected with hiv-1, confirmed th ... | 2001 | 11359440 |
| leishmaniasis in sudan. mucosal leishmaniasis. | sudanese mucosal leishmaniasis is a chronic infection of the upper respiratory tract and/or oral mucosa caused mainly by leishmania donovani. the disease occurs in areas of the country endemic for visceral leishmaniasis, particularly among masalit and other closely related tribes in western sudan. the condition may develop during or after an attack of visceral leishmaniasis, but in most cases it is a primary mucosal disease. unlike south american mucocutaneous leishmaniasis, mucosal leishmaniasi ... | 2001 | 11370249 |
| leishmaniasis in sudan. post kala-azar dermal leishmaniasis. | post kala-azar dermal leishmaniasis (pkdl) is increasingly recognized in sudan as a complication of visceral leishmaniasis (vl), occurring in c. 55% of patients after, or during treatment of, vl. the development of pkdl seems to be restricted to parasites of the leishmania donovani sensu stricto cluster; no particular zymodeme has been found to be associated with it. in contrast to pkdl in india, pkdl in sudan occurs within 0-6 months after treatment for vl. the rash may be macular, maculo-papul ... | 2001 | 11370251 |
| use of the recombinant k39 dipstick test and the direct agglutination test in a setting endemic for visceral leishmaniasis in nepal. | we evaluated the field use of two serologic tests for visceral leishmaniasis (vl), the direct agglutination test (dat) and rk39 dipstick test, in the context of a case-control study. most vl cases in nepal are currently diagnosed on clinical grounds and with relatively non-specific tests such as the formol-gel test. among 14 newly diagnosed vl patients with bone-marrow slides confirmed positive in two independent laboratories, the sensitivity of both tests was 100%. among 113 controls with no pe ... | 2000 | 11388508 |
| molecular genetics of nucleoside transporters in leishmania and african trypanosomes. | nucleoside transporters play central roles in the biochemistry of parasitic protozoa such as leishmania and african trypanosomes, because these parasites cannot synthesize purines de novo and are absolutely reliant upon purine salvage from their hosts. furthermore, nucleoside transporters are important to the pharmacology of these significant human pathogens, because they mediate the uptake of purine analogs, as well as some non-purine drugs, that are selectively cytotoxic to the parasites. rece ... | 2001 | 11389872 |
| the egyptian mongoose, herpestes ichneumon, is a possible reservoir host of visceral leishmaniasis in eastern sudan. | investigations were made on possible reservoir hosts of leishmania donovani in 2 zoonotic foci of visceral leishmaniasis (vl) in dinder national park (dnp) and the peri-domestic habitats of adjacent villages of eastern sudan. animals were captured, in november 1997-1998 and april-may 1999 and examined for l. donovani infection using light microscopy and 2 sensitive polymerase chain reaction (pcr) systems. microscopy and pcr investigations were also used to determine the infection rates of l. don ... | 2001 | 11393826 |
| evidence for the extracellular reduction of alpha-lipoic acid by leishmania donovani promastigotes: a transplasma membrane redox system. | leishmania donovani cells, capable of reducing certain electron acceptors with redox potentials at ph 7.0 down to -290 mv, outside the plasma membrane, can reduce the oxidised form of alpha-lipoic acid. alpha-lipoic acid has been used as natural electron acceptor probe for studying the mechanism of transplasma membrane electron transport. transmembrane alpha-lipoic acid reduction by leishmania was not inhibited by mitochondrial inhibitors as azide, cyanide, rotenone or antimycin a, but responded ... | 2001 | 11406092 |
| inhibition of fumarate reductase in leishmania major and l. donovani by chalcones. | our previous studies have shown that chalcones exhibit potent antileishmanial and antimalarial activities in vitro and in vivo. preliminary studies showed that these compounds destroyed the ultrastructure of leishmania parasite mitochondria and inhibited the respiration and the activity of mitochondrial dehydrogenases of leishmania parasites. the present study was designed to further investigate the mechanism of action of chalcones, focusing on the parasite respiratory chain. the data show that ... | 2001 | 11408218 |
| re-emergence of visceral leischmaniasis: important diagnostic features. | | 2001 | 11419687 |
| genetic analysis of spermidine synthase from leishmania donovani. | the polyamine biosynthetic pathway of protozoan parasites has been validated as a target in antiparasitic chemotherapy. to investigate this pathway at the biochemical and genetic level in a model parasite, the gene encoding spermidine synthase (spdsyn), a key polyamine biosynthetic enzyme, has been cloned and sequenced from leishmania donovani. the l. donovani spdsyn gene encodes a polypeptide of 300 amino acids that exhibits 56% amino acid identity with the human counterpart. spdsyn is present ... | 2001 | 11420108 |
| tc45, a dimorphic trypanosoma cruzi immunogen with variable chromosomal localization, is calreticulin. | we demonstrate that tc45, a polypeptide described as an immunogenetically restricted trypanosoma cruzi antigen in mice, is calreticulin, a dimorphic molecule encoded by genes with variable chromosomal distribution. previously we showed that igg from a.sw (h2s) mice immunized with t. cruzi trypomastigotes or epimastigotes and sera from infected humans recognize tc45, a 45 kd parasite polypeptide. herein we describe the cloning, sequencing, and expression of the tc45 gene. a 98% homology in the de ... | 2000 | 11421383 |
| tannins and related compounds: killing of amastigotes of leishmania donovani and release of nitric oxide and tumour necrosis factor alpha in macrophages in vitro. | the antileishmanial and immunomodulatory potencies of a series of 28 polyphenols were evaluated in terms of extra- and intracellular leishmanicidal activity and macrophage activation for release of nitric oxide (no), tumour necrosis factor (tnf) and interferon (ifn)-like properties. for this, several functional bioassays were employed including an in vitro model for leishmaniasis in which murine bone marrow-derived macrophages (bmmphi) were infected with the obligate intracellular parasite leish ... | 2001 | 11421463 |
| dose-dependent differential effect of hemin on protein synthesis and cell proliferation in leishmania donovani promastigotes cultured in vitro. | leishmania donovani requires an exogenous source of heme for growth and transformation. in in vitro culture of the free-living promastigotes, exogenously added hemin enhances cell proliferation. in this investigation, the question of the function of heme with particular reference to protein synthesis and cell proliferation has been addressed. the results of in vitro cell culture experiments demonstrated that hemin (10 microm) alone is suitable for supporting optimum level of protein synthesis, a ... | 2001 | 11426058 |