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increase in cytosolic ca2+ levels through the activation of non-selective cation channels induced by oxidative stress causes mitochondrial depolarization leading to apoptosis-like death in leishmania donovani promastigotes.reactive oxygen species are important regulators of protozoal infection. promastigotes of leishmania donovani, the causative agent of kala-azar, undergo an apoptosis-like death upon exposure to h2o2. the present study shows that upon activation of death response by h2o2, a dose- and time-dependent loss of mitochondrial membrane potential occurs. this loss is accompanied by a depletion of cellular glutathione, but cardiolipin content or thiol oxidation status remains unchanged. atp levels are red ...200211983701
leishmania donovani transmission by packed rbc transfusion to anemic dogs in the united states. 200211961247
design and antileishmanial activity of amphotericin b-loaded stable ionic amphiphile biovector formulations.a new delivery system, ionic amphiphilic biovector (abv), comprised of anionic lipids (dipalmitoyl phosphatidyl glycerol) included in a cationic cross-linked polysaccharide matrix was used as a reservoir for amphotericin b (amb). two abv formulations exhibited an in vitro and in vivo efficacy similar to commercial ambisome against leishmania donovani-infected mice. the higher stability of these abv formulations indicates their potential for further development and applications.200211959611
serodiagnostic and immunoprophylactic potential of a 78kda protein of leishmania donovani of indian origin.the serodiagnosis of visceral leishmaniasis due to leishmania donovani using crude parasite antigen is complicated in many endemic areas by cross-reactions with serum from humans infected with other protozoan diseases. the search for pure antigens avoiding such cross-reactions is in progress. developing a vaccine against cutaneous leishmaniasis has been much more successful than against visceral leishmaniasis. immunoprophylactic studies using various combinations of antigens and adjuvants are al ...200211951057
in vitro and in vivo activities of three acridine thioethers against leishmania donovani.the lack of definitive chemotherapeutic agents to fight against visceral leishmaniasis has lead to the testing of numerous compounds. in the present work, we carry out an in-depth study of the activity against leishmania donovani of three acridine derivatives both in vitro and in vivo. these compounds have proven to be highly effective at medium and high concentrations of 10 microg/ml, against both flagellate and nonflagellate forms of the parasite, which, though obtained in vitro, closely resem ...200211937777
analysis of stereoelectronic properties, mechanism of action and pharmacophore of synthetic indolo[2,1-b]quinazoline-6,12-dione derivatives in relation to antileishmanial activity using quantum chemical, cyclic voltammetry and 3-d-qsar catalyst procedures.several indolo[2,1-b]quinazoline-6,12-dione (tryptanthrin) derivatives exhibited remarkable activity at concentrations below 100 ng/ml when tested against in vitro leishmania donovani amastigotes. the in vitro toxicity studies indicate that the compounds are fairly well tolerated in both macrophage and neuronal lines. an analysis based on qualitative and quantitative structure-activity relationship studies between in vitro antileishmanial activity and molecular electronic structure of 27 analogu ...200211937358
synthesis of a novel quinoline derivative, 2-(2-methylquinolin-4-ylamino)-n-phenylacetamide--a potential antileishmanial agent.some novel quinoline derivatives were prepared and tested for antileishmanial activity. 2-(2-methylquinolin-4-ylamino)-n-phenylacetamide (2) was found to be significantly more active than the standard antileishmanial drug sodium antimony gluconate (sag) in reducing the parasite load both in the spleen and liver at a much lower concentration in hamster models. the results suggest that the compound could be exploited as an antileishmanial drug.200211937327
klaivanolide, an antiprotozoal lactone from uvaria klaineana.bioguided-fractionation of a ch(2)cl(2) extract of the stems of uvaria klaineana (annonaceae) led to isolation of klaivanolide, a novel bisunsaturated 7-membered lactone (5-acetoxy-7-benzoyloxymethyl-7h-oxepin-2-one), together with benzyl benzoate. klaivanolide showed potent in vitro antileishmanial activity against both sensitive and amphotericin b-resistant promastigote forms of leishmania donovani with ic(50) values of 1.75 and 3.12 microm, respectively. the compound also showed in vitro tryp ...200211937171
expression of biopterin transporter (bt1) protein in leishmania.the present work focuses on the growth phase regulated expression of biopterin transporter gene (bt1) from the ld1 locus on chromosome 35 of leishmania donovani. antiserum against recombinant bt1 detected a polypeptide of 45 kda of equal intensity at lag, log and stationary phases of promastigote growth, both in l. donovani strain lsb-7.1 (mhom/bl/67/itmap263), and strain lsb-146.1 (hom/ir/95/x81), a natural isolate from isfehan, iran that caused cutaneous leishmaniasis. however, in both these s ...200211934499
synthesis of plumbagin derivatives and their inhibitory activities against ehrlich ascites carcinoma in vivo and leishmania donovani promastigotes in vitro.plumbagin, a plant-derived bioactive naphthoquinonoid compound, was converted to a hydroquinonoid derivative, which was studied for its tumour-inhibitory and antileishmanial activities for the first time. a similar chemical transformation was undertaken on an analogous dimeric compound, diospyrin, and its bioassay results were compared with those of the plumbagin derivative. synthesis of the derivative of plumbagin did not result in a marked enhancement of the tumour-inhibitory activity, whereas ...200211933114
kala-azar: a potentially eradicable disease as a public health challenge. 200111917322
transplasma membrane electron transport in leishmania donovani promastigotes.leishmania donovani promastigotes are capable of reducing certain electron acceptors with redox potential at ph 7 down to -125 mv; outside the plasma membrane promastigotes can reduce ferricyanide. ferricyanide has been used as an artificial electron acceptor probe for studying the mechanism of transplasma membrane electron transport. transmembrane ferricyanide reduction by l. donovani promastigotes was not inhibited by such mitochondrial inhibitors as antimycin a or cyanide, but it responded to ...200211908895
kinetic mechanism of adenine phosphoribosyltransferase from leishmania donovani.adenine phosphoribosyltransferase (aprt, ec 2.4.2.7) catalyzes the reversible phosphoribosylation of adenine from alpha-d-5-phosphoribosyl-1-pyrophosphate (prpp) to form amp and pp(i). three-dimensional structures of the dimeric aprt enzyme from leishmania donovani (ldaprt) bear many similarities to other members of the type 1 phosphoribosyltransferase family but do not reveal the structural basis for catalysis (phillips, c. l., ullman, b., brennan, r. g., and hill, c. p. (1999) embo j. 18, 3533 ...200211900545
nucleoside hydrolase from leishmania (l.) donovani is an antigen diagnostic for visceral leishmaniasis. 200211897139
high affinity binding between laminin and laminin binding protein of leishmania is stimulated by zinc and may involve laminin zinc-finger like sequences.in the course of trying to understand the pathogenesis of leishmaniasis in relation to extracellular matrix (ecm) elements, laminin, a major ecm protein, has been found to bind saturably and with high affinity to a 67-kda cell surface protein of leishmania donovani. this interaction involves a single class of binding sites, which are ionic in nature, conformation-dependent and possibly involves sulfhydryls. binding activity was significantly enhanced by zn2+, an effect possibly mediated through ...200211895432
[visceral leishmaniasis in cameroon. seroepidemiologic survey in the kousseri region, north cameroon].a sero-epidemiological survey of school children was carried out in kousseri, a focus for visceral leishmaniasis. sero-immunological assays for the detection of anti-leishmania antibodies were based on the indirect immunofluorescence assay test and counter-immunoelectrophoresis. 9 out of 223 school children tested positive for visceral leishmaniasis (seroprevalence rate of 4%). these 9 cases had no history of the disease. the data obtained confirm the endemicity of visceral leishmaniasis in this ...200111889946
leishmania donovani: expression and characterization of escherichia coli-expressed recombinant chitinase ldcht1.leishmania parasites produce chitinase activity (ec. 3.2.1.14) thought to be important in parasite-sandfly interactions and transmission of the parasite to the vertebrate host. previous observations have suggested that parasite chitinases are involved in degradation of the sandfly peritrophic matrix and the chitinous layer of the cardiac valve cuticle. this chitinase activity is thought to produce an incompetent pharyngeal valve sphincter and a route of egress that allow leishmania promastigotes ...200111888249
specific recognition and cleavage of galectin-3 by leishmania major through species-specific polygalactose epitope.lipophosphoglycan is a major surface molecule of leishmania, protozoa parasites, which are the causative agents of leishmaniasis, a disease that annually afflicts millions of people worldwide. the oligosaccharide structures of lipophosphoglycan varies among species, and epitopes of these species-specific oligosaccharides are suggested to be implicated in the interaction of leishmania with macrophages as well as species-specific tissue tropism observed in leishmaniasis. the recognition of the spe ...200211882664
molecular dissection of the functional domains of a unique, tartrate-resistant, surface membrane acid phosphatase in the primitive human pathogen leishmania donovani.the primitive trypanosomatid pathogen of humans, leishmania donovani, constitutively expresses a unique externally oriented, tartrate-resistant, acid phosphatase on its surface membrane. this is of interest because these organisms are obligate intracellular protozoan parasites that reside and multiply within the hydrolytic milieu of mammalian macrophage phago-lysosomes. here we report the identification of the gene encoding this novel l. donovani enzyme. in addition, we characterized its structu ...200211882658
evaluation of enzyme-linked immunosorbent assay for diagnosis of post-kala-azar dermal leishmaniasis with crude or recombinant k39 antigen.the diagnosis of post-kala-azar dermal leishmaniasis (pkdl), a dermatosis that provides the only known reservoir for the parasite leishmania donovani in india, remains a problem. timely recognition and treatment of pkdl would contribute significantly to the control of kala-azar. we evaluated here the potential of the enzyme-linked immunosorbent assay (elisa) as a diagnostic tool for pkdl. antigen prepared from promastigotes and axenic amastigotes with parasite isolates that were derived from ski ...200211874880
inhibition of mononuclear cell procoagulant activity by lipophosphoglycan of leishmania donovani.background: since fibrin formation is an expression of the response of the host to parasite spread, the lipophosphoglycan (lpg) of leishmania donovani and its carbohydrate fragment (pg) were examined for their capacity to inhibit procoagulant activity (pca) production by human mononuclear cells stimulated with escherichia coli endotoxin in vitro. methods: the putative inhibitory effect of lpg and its pg fragment was evaluated on the basis of their in vitro capacity to prolong significantly the t ...199511866718
leishmania-induced cellular recruitment during the early inflammatory response: modulation of proinflammatory mediators.this study investigated whether leishmania species, the etiologic agent of cutaneous (leishmania major) and visceral (leishmania donovani) leishmaniasis, could differentially elicit early inflammatory events in vivo correlating with the subsequent development of their reciprocal pathogenesis. by use of the murine air pouch system, injection of leishmania led to a rapid and transient accumulation of a mixed population of leukocytes, and l. major recruited 31-fold more leukocytes than did controls ...200211865425
[treatment of visceral leishmaniasis: efficacy and limits of miltefosine]. 200111861203
kala azar associated with malaria. 200211860324
epidemiology and clinical manifestations of leishmania donovani infection in two villages in an endemic area in eastern sudan.we conducted a longitudinal study in an endemic area for visceral leishmaniasis (vl) in eastern sudan to compare the epidemiology and clinical spectrum of leishmania donovani infection in two populations differing in ethnic background and duration of residence in the area. the study took place in two villages from april 1994 to april 1996. in um-salala village, which is inhabited by members of the masaleet tribe, half of the villagers had previous exposure to cutaneous leishmaniasis (leishmaria ...200211851953
in vivo activities of farnesyl pyrophosphate synthase inhibitors against leishmania donovani and toxoplasma gondii.the in vivo activities of three bisphosphonates were determined against leishmania donovani and toxoplasma gondii. alendronate was essentially inactive against both parasites. pamidronate was active against l. donovani by intravenous administration. risedronate had a 50% effective dosage of five 2.6-mg/kg of body weight intraperitoneal doses against l. donovani-infected mice but was less effective against t. gondii-infected mice.200211850291
antileishmanial activities of several classes of aromatic dications.aromatic dicationic molecules possess impressive activity against a broad spectrum of microbial pathogens, including pneumocystis carinii, cryptosporidium parvum, and candida albicans. in this work, 58 aromatic cations were examined for inhibitory activity against axenic amastigote-like leishmania donovani parasites. in general, the most potent of the compounds were substituted diphenyl furan and thiophene dications. 2,5-bis-(4-amidinophenyl)thiophene was the most active compound. this agent dis ...200211850264
purification and enzymatic activity of an nadh-fumarate reductase and other mitochondrial activities of leishmania parasites.a 65 kd membrane-associated nadh-fumarate reductase subunit, which has a molecular weight similar to that of one of the enzyme subunits from bacteria, was purified from leishmania donovani promastigotes. nadh-fumarate reductase and other mitochondrial enzymatic activities of l. major and l. donovani promastigotes and amastigotes were investigated. the presence of nadh-fumarate reductase was demonstrated in digitonin-permeabilized l. major promastigotes and mitochondria of l. major and l. donovan ...200111846720
bacopasaponin c: critical evaluation of anti-leishmanial properties in various delivery modes.bacopasaponin c, an indigenous glycoside, was isolated from indian medicinal plant bacopa monniera (b. brahmi) and was tested for antileishmanial properties both in free and in various delivery modes, e.g., niosomes, microspheres, and nanoparticles that are used now as alternatives to more commonly used liposomes. the different vesicles were prepared by published protocols. the percent intercalation of bacopasaponin c in liposomes, niosomes, and micropspheres determined at its absorption maximal ...200211839209
effect of immunization with lipid associated polysaccharide antigen and anti cd-2 antibodies on class ii mhc expression and cellular immune response in balb/c mice infected with leishmania donovani.in a bid to characterize the antigens and immunization mechanisms which may be used to produce a protective response against l. donovani, role of lipid associated polysaccharide (lps) antigen and whole antigen was evaluated. balb/c mice were immunized with whole or lps antigen in combination with one of three putative adjuvents (anti cd-2 antibody/fia/0.85% saline). lps antigen emulsified in anti cd-2 antibody was found to induce significant antibodies in mice on day 28 against challenge with le ...200111831368
ethiopian visceral leishmaniasis: generic and proprietary sodium stibogluconate are equivalent; hiv co-infected patients have a poor outcome.we evaluated generic sodium stibogluconate (ssg) (international dispensary association, amsterdam) versus pentostam (sodium stibogluconate, glaxowellcome, london) under field conditions in ethiopian patients with visceral leishmaniasis (vl; kala-azar). the 199 patients were randomly assigned to pentostam (n = 104) or ssg (n = 95) in 1998/99; both drugs were given at 20 mg/kg intra-muscularly for 30 days. a clinical cure after 30-days treatment was achieved in 70.2% (pentostam) and 81.1% (ssg). t ...200111816442
genomic organization and functional expression of differentially regulated cysteine protease genes of leishmania donovani complex.for the first time, we report the genomic organization and characterization of cathepsin l-like cysteine protease gene cluster from the members of leishmania donovani complex. the cysteine protease gene cluster of leishmania chagasi has five copies of tandemly arranged genes. the first gene (ldccys1a) is identical to ldccys1 cdna and is predominantly expressed in promastigotes. the last gene (ldccys1e) is identical to ldccys1a with a 13 amino acids deletion in the mature domain, including one of ...200211814698
a plasma membrane p-type h(+)-atpase regulates intracellular ph in leishmania mexicana amazonensis.a recent report (mukherjee et al., j. biol. chem. 276 (2001) 5563) has proposed that the plasma membrane mg(+)-atpase of promastigotes of leishmania donovani, that is involved in its intracellular ph regulation, is an electroneutral h(+)/k(+) antiporter rather than an electrogenic h(+) pump. since this proposition has important implications for the use of the pump as a target for chemotherapy, we investigated its nature in the mammalian stage (amastigote) of l. mexicana amazonensis and compared ...200211814574
a low-background inducible promoter system in leishmania donovani.we report here a second-generation tetracycline-responsive repressor-operator system in leishmania donovani. in this system, expression of a reporter luciferase gene (luc) is driven by the inducible leishmania ribosomal rna promoter on the dna strand opposite to a hygromycin resistance gene (hyg) whose expression is driven by the endogenous pol i promoter on chromosome 27 (rdna locus) or the endogenous pol ii promoter on chromosome 35 (ld1 locus). transgenic cell lines showed regulation of luc g ...200211814573
angiogenesis inhibitors specific for methionine aminopeptidase 2 as drugs for malaria and leishmaniasis.methionine aminopeptidase 2 (metap2) is responsible for the hydrolysis of the initiator methionine molecule from the majority of newly synthesized proteins. we have cloned the metap2 gene from the malaria parasite plasmodium falciparum (pfmetap2; genbank accession number af348320). the cloned pfmetap2 has no intron, consists of 1,544 bp and encodes a protein of 354 amino acids with a molecular mass of 40,537 d and an overall base composition of 72.54% a + t. pfmetap2 has 40% sequence identity wi ...200211810023
an insight into the active site of a type i dna topoisomerase from the kinetoplastid protozoan leishmania donovani.dna topoisomerases are ubiquitous enzymes that govern the topological interconversions of dna thereby playing a key role in many aspects of nucleic acid metabolism. recently determined crystal structures of topoisomerase fragments, representing nearly all the known subclasses, have been solved. the type ib enzymes are structurally distinct from other known topoisomerases but are similar to a class of enzymes referred to as tyrosine recombinases. a putative topoisomerase i open reading frame from ...200211809893
programmed cell death in the unicellular protozoan parasite leishmania.in the present study we have demonstrated some features characterizing programmed cell death (pcd) in the unicellular protozoan parasite leishmania donovani, the causative agent of visceral leishmaniasis. we report that pcd is initiated in stationary phase cultures of promastigotes and both in actively growing cultures of axenic amastigotes and promastigotes upon treatment with anti leishmanial drugs (pentostam and amphotericin b). however, the two cell types respond to antileishmanial drugs dif ...200211803374
the archaeology of apoptosis. 200211803368
vacuolar type h+ pumping pyrophosphatases of parasitic protozoa.trans-membrane proton pumping is responsible for a myriad of physiological processes including the generation of proton motive force that drives bioenergetics. among the various proton pumping enzymes, vacuolar pyrophosphatases (v-ppases) form a distinct class of proton pumps, which are characterised by their ability to translocate protons across a membrane by using the potential energy released by hydrolysis of the phosphoanhydride bond of inorganic pyrophosphate. until recently, v-ppases were ...200211796117
tryparedoxin peroxidase of leishmania donovani: molecular cloning, heterologous expression, specificity, and catalytic mechanism.tryparedoxin peroxidase (txnpx) of trypanosomatidae is the terminal peroxidase of a complex redox cascade that detoxifies hydroperoxides by nadph (nogoceke et al., biol. chem. 378, 827-836, 1997). a gene putatively coding for a peroxiredoxin-type txnpx was identified in l. donovani and expressed in escherichia coli to yield an n-terminally his-tagged protein (ldh6txnpx). ldh6txnpx proved to be an active peroxidase with tryparedoxin (txn) 1 and 2 of crithidia fasciculata as cosubstrates. ldh6txnp ...200211795890
a case of pyrexia, hepatosplenomegaly, cytopenia and hypergammaglobulinemia. 200111780210
heat shock protein 100 and the amastigote stage-specific a2 proteins of leishmania donovani.hsp100 protein in leishmania spp. plays an important role for the survival and integrity of intracellular amastigotes. the a2 proteins of l. donovani are functionally linked to hsp100. there is evidence for an interdependence between these two proteins, which are both expressed predominantly in the amastigote stage of leishmania donovani. mutant strains lacking either of these proteins display very similar phenotypes, i.e. loss of virulence both in vivo and in vitro. also, both proteins colocali ...200111770109
leishmania infection and virulence.leishmaniasis is among the most important infectious diseases of the developing world. with the advent of effective culture conditions for the various stages of the life cycle, together with state of the art biochemical, genomics, and reverse genetic approaches, it has been possible to identify virulence factors required for the infection process. several of these virulence factors are discussed within including lipophosphoglygan, a2, cysteine proteinases, and gp63.200111770107
comparative proteome analysis of leishmania donovani at different stages of transformation from promastigotes to amastigotes.to pass through its life cycle, protozoan parasites of the genus leishmania have to differentiate from promastigotes to amastigotes. the molecular basis underiving this major transformation is poorly understood. one way to study this phenomenon is to isolate and characterize proteins that are specifically expressed in one of the two stages of the life cycle or during the stage differentiation. using two-dimensional gel electrophoresis, we mapped the leishmania donovani proteome during stage diff ...200111770106
the heat shock protein 90 of leishmania donovani.the 90-kda heat shock protein (hsp90) of leishmania donovani is a highly abundant cytoplasmic protein and is involved in a variety of cellular processes. pharmacological deactivation of hsp90 leads to growth arrest and induces the synthesis of heat shock proteins. moreover, treatment of promastigote parasites with hsp90 inhibitors induces the synthesis of amastigote-specific marker proteins and a morphological alteration similar to axenic amastigote differentiation. we propose a role for hsp90 i ...200111770104
combination therapy with indolylquinoline derivative and sodium antimony gluconate cures established visceral leishmaniasis in hamsters.2-(2"-dichloroacetamidobenzyl)-3-(3'-indolylquinoline), designated indolylquinoline derivative a, reduced the splenic and the liver parasite burdens by >93.0% in leishmania donovani-infected hamsters, whereas sodium antimony gluconate (sag) reduced the burdens approximately 80.0%. complete clearance of parasitemia from the livers and spleens was noticed when infected animals received indolylquinoline derivative a plus sag, suggesting that indolylquinoline derivative a has potential as a new agen ...200211751149
reduced infectivity of a leishmania donovani biopterin transporter genetic mutant and its use as an attenuated strain for vaccination.pterins are essential for the growth of leishmania species, and recent work has led to the isolation of the biopterin transporter bt1. in this study, we inactivated the leishmania donovani biopterin transporter bt1 by gene disruption mediated by homologous recombination. no transport of biopterin was detected in this mutant. the l. donovani bt1 null mutant showed a much lesser capacity for inducing infection in mice than wild-type parasites and could elicit protective immunity in mice susceptibl ...200211748164
in vitro antiprotozoal activity of extract and compounds from the stem bark of combretum molle.the antiprotozoal activity of the ethiopian medicinal plant combretum molle (r. br. ex g. don.) engl & diels (combretaceae) was evaluated by in vitro testing against plasmodium falciparum, trypanosoma brucei rhodesiense, trypanosoma cruzi and leishmania donovani. the acetone fraction of the stem bark of this plant prepared by soxhlet extraction was inactive against the intracellular amastigotes of l. donovani and t. cruzi in murine peritoneal macrophages but showed significant activity against e ...200111746844
antileishmanial activity of hydrolyzable tannins and their modulatory effects on nitric oxide and tumour necrosis factor-alpha release in macrophages in vitro.a series of 27 hydrolyzable tannins and related compounds was tested for antiparasitic effects against both extracellular promastigote and intracellular amastigote leishmania donovani organisms. in parallel, the compounds were evaluated for their immunomodulatory effects on macrophage functions, including release of nitric oxide (no), tumour necrosis factor-alpha (tnf-alpha) and interferon (ifn)-like properties using several functional assays. of the series of polyphenols tested, only gallic aci ...200111745019
a nonspecific nucleoside hydrolase from leishmania donovani: implications for purine salvage by the parasite.in contrast to their mammalian hosts, protozoan parasites do not synthesize purines de novo, but depend on preformed nucleotides that they purportedly obtain by salvage pathways. nucleoside hydrolases may play a crucial role in that salvage process. by screening leishmania donovani libraries with polyclonal antibodies against promastigote soluble exo-antigens, we have identified a cdna encoding a protein with significant homology to nonspecific and uridine-inosine-preferring nucleoside hydrolase ...200111738828
s-adenosylmethionine decarboxylase from leishmania donovani. molecular, genetic, and biochemical characterization of null mutants and overproducers.the polyamine biosynthetic enzyme, s-adenosylmethionine decarboxylase (adometdc) has been advanced as a potential target for antiparasitic chemotherapy. to investigate the importance of this protein in a model parasite, the gene encoding adometdc has been cloned and sequenced from leishmania donovani. the delta adometdc null mutants were created in the insect vector form of the parasite by double targeted gene replacement. the delta adometdc strains were incapable of growth in medium without pol ...200211734561
n-(2-hydroxypropyl)methacrylamide (hpma) copolymers for targeted delivery of 8-aminoquinoline antileishmanial drugs.a challenge to successful chemotherapy of visceral leishmaniasis is the dose-limiting toxicity of antileishmanial agents. one approach to increase the efficacy and reduce the toxicity of these agents is to direct the drug to the phagolysosomes of the reticuloendothelial system (res) where the leishmanial parasites reside. in this work a series of n-(2-hydroxypropyl)methacrylamide (hpma) copolymer-antileishmanial drug conjugates containing lysosomally degradable side chains and with or without su ...200111733091
early response gene expression during differentiation of cultured leishmania donovani.the promastigote form of the unicellular parasite, leishmania donovani, must differentiate into the amastigote form to establish an infection in a mammalian host. identification of genes whose expression changes during differentiation could help reveal mechanisms of leishmania gene regulation and identify targets for controlling the diseases caused by this human pathogen. two genomic clones were isolated, p9 that is more highly expressed in promastigotes than in axenic amastigotes and a14 that i ...200111728012
detection of leishmania causing visceral leishmaniasis in the old and new worlds by a polymerase chain reaction assay based on telomeric sequences.we present a new polymerase chain reaction assay based on telomeric sequences of leishmania donovani. when this assay was used in dilutions of purified l. donovani dna, a strong amplification signal was observed with 1 fg of dna. in a specificity test that used purified dna from old world and new world leishmania, the assay recognized all parasites isolated from patients with visceral leishmaniasis, except for 2 isolates of leishmania colombiensis from venezuela and 1 isolate from brazil. all le ...200111716117
efficacies of vesicular and free sodium stibogluconate formulations against clinical isolates of leishmania donovani.in this study, the in vitro and in vivo efficacies of free sodium stibogluconate (ssg) and a nonionic surfactant vesicular formulation of ssg (ssg-niv) against a laboratory strain of leishmania donovani (mhom/et/67:lv82) and different clinical isolates of l. donovani were determined. treatment with ssg-niv was more effective against intramacrophage amastigotes than treatment with ssg. in vivo murine studies showed that there was interstrain variability in the infectivity of the different l. dono ...200111709339
leishmania donovani: evolution and architecture of the splenic cellular immune response related to control of infection.infection with the protozoan leishmania donovani in humans is usually subclinical. parasites probably persist for the life of the host and the low-level infection is controlled by the cellular immune response. to better understand the mechanisms related to the control of infection, we studied the evolution and architecture of the splenic cellular immune response in a murine model that is most representative of human subclinical infection. following systemic inoculation with l. donovani, the para ...200111708830
drug resistance in indian visceral leishmaniasis.throughout the world, pentavalent antimonial compounds (sb(v)) have been the mainstay of antileishmanial therapy for more than 50 years. sb(v) has been highly effective in the treatment of indian visceral leishmaniasis (vl: kala-azar) at a low dose (10 mg/kg) for short durations (6-10 days). but in the early 1980s reports of its ineffectiveness emerged, and the dose of sb(v) was eventually raised to 20 mg/kg for 30-40 days. this regimen cures most patients with vl except in india, where the prop ...200111703838
tissue granuloma structure-function in experimental visceral leishmaniasis.in experimental visceral leishmaniasis in normal mice (balb/c, c57bl/6) acquired resistance to leishmania donovani, a protozoan which targets tissue macrophages, depends upon t cells, th1 cell-type cytokine generation and activated mononuclear phagocytes. in the intact host, initial control and eventual resolution of l. donovani hepatic infection in normal mice is expressed by and accomplished within well-formed, mature tissue granulomas. in the liver, these immunologically active, inflammatory ...200111703536
a simple and sensitive test for field diagnosis of post kala-azar dermal leishmaniasis.current methods for diagnosis of post kala-azar dermal leishmaniasis (pkdl) do not offer adequate sensitivity and specificity.200111703291
effect of leishmania donovani lipophosphoglycan on ornithine decarboxylase activity in macrophages.lipophosphoglycan (lpg), a major surface molecule from leishmania donovani, stimulated ornithine decarboxylase (odc) activity in macrophages in a dose- and time-dependent manner. lpg stimulated the rapid increase in odc activity within 30 min after exposure, suggesting that the interaction of lpg with its receptor stimulated a specific signal transduction pathway. however, lpg-induced odc activity was a transient event because 3 hr after exposure to lpg, no stimulation of odc activity was detect ...200111695367
modulation of macrophage mannose receptor affects the uptake of virulent and avirulent leishmania donovani promastigotes.the effect of oxidants and the anti-inflammatory steroid dexamethasone on the attachment and internalization of virulent and avirulent leishmania donovani promastigotes by the macrophage mannosyl fucosyl receptor was examined. oxidants and dexamethasone are known to down- and upregulate the expression of the mannose receptor. macrophages, when treated with 500 microm h2o2 at 37 c for 30 min, stimulate about 45% inhibition in uptake of an avirulent strain (ur6), and 30 and 25% inhibition for viru ...200111695359
heat shock protein 90 homeostasis controls stage differentiation in leishmania donovani.the differentiation of leishmania parasites from the insect stage, the promastigote, toward the pathogenic mammalian stage, the amastigote, is triggered primarily by the rise in ambient temperature encountered during the insect-to-mammal transmission. we show here that inactivation of heat shock protein (hsp) 90, with the use of the drugs geldanamycin or radicicol, mimics transmission and induces the differentiation from the promastigote to the amastigote stage. geldanamycin also induces a growt ...200111694568
ca2+ signaling in the transformation of promastigotes to axenic amastigotes of leishmania donovani.the present study is an attempt to look into the role of ca2+ in signaling the transformation of promastigotes to axenic amastigotes. an estimation of intracellular free calcium concentration at 6 h intervals during the conversion of promastigotes to axenic amastigotes (72 h) revealed a 10 fold increase in [ca2+]i at the initial 6-12 h during the conversion. this was followed by declining levels till 60 h and the concentration thereafter remained constant. axenic amastigotes (72 h) had a 5 fold ...200111693198
enzyme-linked immunosorbent assay for recombinant k39 antigen in diagnosis and prognosis of indian visceral leishmaniasis.the recombinant product (rk39) of the 39-amino-acid repeats encoded by a kinesin-like protein-encoding gene of leishmania chagasi was evaluated by enzyme-linked immunosorbent assay (elisa) for diagnostic potential and the ability to predict the response to therapy in indian kala-azar or visceral leishmaniasis (vl); we also compared its performance with that of crude soluble antigen (csa). at the diagnosis of vl, the anti-rk39 antibody titer was 59-fold higher than the anti-csa antibody titer. wi ...200111687466
isolation of leishmania infantum, zymodeme mon-1 from canine and human visceral leishmaniasis on margarita island, venezuela.an increase in the incidence of human visceral leishmaniasis (hvl) has been detected in recent years on margarita island, located off the ne coast of venezuela. recent studies have revealed reactivity to rk39 antigen (leishmania chagasi) in 20% of 541 sera from domestic dogs in endemic communities; pcr reactions were positive using primers for the l. donovani complex. here we report that isolates from human and canine infection, identified by isoenzyme analysis, correspond to l. infantum, zymode ...200111685252
generation of ceramide in murine macrophages infected with leishmania donovani alters macrophage signaling events and aids intracellular parasitic survival.in the present study, we examined the involvement of intracellular ceramide in host pathogen interaction of balb/c mouse peritoneal macrophages infected with the obligate intracellular protozoan, leishmania donovani. our findings indicate that the level of intracellular ceramide was enhanced as a result of the in vitro infection. while the elevated ceramide was largely due to de novo synthesis, activation of the sphingomyelinases was also observed. the enhanced ceramide was responsible for the d ...200111681721
attenuated toxoplasma gondii ts-4 mutants engineered to express the leishmania antigen kmp-11 elicit a specific immune response in balb/c mice.in order to test recombinant toxoplasma as adjuvant and live vaccine carrier in the infectious disease model of murine experimental leishmaniasis, we engineered the attenuated, temperature-sensitive toxoplasma gondii strain ts-4 to express the heterologous leishmania antigen kinetoplastid membrane protein-11 (kmp-11). transgenic ts-4 clones were obtained which express kmp-11 as cytoplasmatic protein or target it to the secretory pathway of the tachyzoites. immunization of balb/c mice with these ...200111672909
successful replacement of fetal calf serum with human urine for in vitro culture of leishmania donovani.leishmania donovani causes visceral leishmaniasis claiming several thousand lives every year in indian sub-continent. the etiological agent is grown in cell free media supplemented with fetal calf serum (fcs). urine from human beings and other mammalian species has also been reported to stimulate growth of leishmania species no study has been carried out leishmania donovani. therefore, we studied the feasibility of culturing leishmania donovani promastigotes in m199 medium supplemented with 10% ...200011668940
clearance of infection with mycobacterium bovis bcg in mice is enhanced by treatment with s28463 (r-848), and its efficiency depends on expression of wild-type nramp1 (resistance allele).the mouse bcg host resistance gene is known to control the activation of host macrophages for killing of intracellular parasites like leishmania donovani as well as intracellular bacteria, including mycobacterium bovis bcg and salmonella enterica serovar typhimurium. the nramp1 gene has been mapped to this locus and affects the efficiency of macrophage activation. it has been shown that imidazoquinoline compounds, including s28463, are able to improve the clearance of a number of intracellular p ...200111600356
inter-current and nosocomial infections among visceral leishmaniasis patients in ethiopia: an observational study.from july 1989 up to september 1997, a total of 247 non-hiv associated visceral leishmaniasis (vl) patients were treated on outpatient basis in rural clinics (195 patients) and hospitalised in the northern-omo regional hospital (18 patients) and in addis ababa referral hospitals (34 patients). patients treated in the rural clinics and in the regional hospital originated from the same endemic area and had comparable baseline characteristics. overall rates of complications (inter-current/concurren ...200111600084
il-10 mediates susceptibility to leishmania donovani infection.human visceral leishmaniasis (vl) results in a severe and potentially fatal systemic disease, accompanied by cellular immune depression. the production of il-10 correlates with ongoing disease and it has been suggested that the cellular immune depression that accompanies active disease may be due to a predominance of il-10 production rather than a lack of ifn-gamma production, which is essential for optimal macrophage activation and parasite elimination. to examine the role of il-10 in resistanc ...200111592059
skinny rodents, kala-azar and prostaglandin e(2). 200111587943
a fast agglutination screening test (fast) for the detection of anti-leishmania antibodies. 200111579883
immunization with a2 protein results in a mixed th1/th2 and a humoral response which protects mice against leishmania donovani infections.the a2 genes of leishmania donovani encode amastigote-specific a2 proteins, which are considered to be virulence factors required for the survival of this protozoan parasite in the mammalian host. the a2 genes are present within a multigene family and corresponding a2 proteins are composed predominantly of multiple copies of a 10 amino acid repeat sequences. a2-specific antibodies have been detected in the sera of patients suffering from visceral leishmaniasis (vl) and it has been shown that gen ...200111567746
molecular and immunological characterisation of the glucose regulated protein 78 of leishmania donovani(1).to identify novel potential leishmania vaccine antigens, antibodies from patients with visceral leishmaniasis (vl) were used to isolate clones from a cdna expression library of l. donovani amastigotes. glucose regulated protein (grp78), a member of the 70 kda heat-shock protein family was identified and characterised. the grp78 gene was localised to chromosome 15 in l. donovani, l. major, and l. mexicana by pulse-field gel electrophoresis. the leishmania grp78 protein contain a carboxy-terminal ...200111566370
resistance to treatment in kala-azar: speciation of isolates from northeast india.kala-azar in india is becoming increasingly difficult to treat, which may be due to the presence of species other than leishmania donovani; leishmania tropica was reported to cause the same clinical syndrome in the area. over the past 3 years, we have collected samples from 241 patients with visceral leishmaniasis from across the region. of the 189 isolates that grew on diphasic medium, 159 were successfully transferred to liquid medium for typing. clinically, 80% of these were resistant to anti ...200111561703
hydrogen peroxide induces apoptosis-like death in leishmania donovani promastigotes.leishmania donovani promastigotes introduced into the bloodstream by sandfly vectors, are exposed to reactive oxygen species like h2o2 during phagocytosis by the host macrophages. h2o2 can induce promastigote death, but the mechanism of induction of this death is not known. studies presented in this paper demonstrate that exposure to 4 mm h2o2 results in a pattern of promastigote death that shares many features with metazoan apoptosis. motility and cell survival in these parasites show a gradual ...200111559754
proanthocyanidins and related compounds: antileishmanial activity and modulatory effects on nitric oxide and tumor necrosis factor-alpha-release in the murine macrophage-like cell line raw 264.7.a series of 17 proanthocyanidins and structurally related compounds was tested for activity against leishmania donovani amastigotes and promastigotes in vitro. most of the polyphenols significantly inhibited the intracellular survival of l. donovani amastigotes (ec50 0.8-10.6 nm) when compared with the antileishmanial drug pentostam (ec50 10.6 nm), but all were inactive against the extracellular form (ec50 7.8 to >86 nm). noteworthy is that all compounds exhibited only moderate or no cytotoxicit ...200111558561
post-kala-azar dermal leishmaniasis: does it play a role in the transmission of leishmania donovani in the sudan?in 1997 a sudden outbreak of visceral leishmaniasis (vl) occurred in eastern sudan, coinciding with an increase of post-kala-azar dermal leishmaniasis (pkdl) cases which may in part be because of sylvatic and anthroponotic transmission. paradoxically, the more vl patients are treated, the higher the frequency of pkdl. if pkdl plays a role in transmission, its treatment would be expected to reduce infection in the area. treatment of pkdl, however, requires four times the amount of pentostam used ...200111555443
dna immunization with trypanosoma cruzi hsp70 fused to the kmp11 protein elicits a cytotoxic and humoral immune response against the antigen and leads to protection.murine immunization with trypanosoma cruzi kmp11-hsp70 fused genes but not the kmp11 gene alone elicited both an immunoglobulin g2a long-lasting humoral immune response against kmp11 protein and activation of cd8+ cytotoxic t lymphocytes specific for two kmp11 peptides containing a2 motifs. moreover, protection against the parasite challenge was observed after immunization with the chimeric gene.200111553607
expression of a mutant form of leishmania donovani centrin reduces the growth of the parasite.leishmania donovani, a protozoan parasite, causes visceral disease in humans. to identify genes that control growth, we have isolated for the first time in the order kinetoplastida a gene encoding for centrin from l. donovani. centrin is a calcium-binding cytoskeletal protein essential for centrosome duplication or segregation. protein sequence similarity and immunoreactivity confirmed that leishmania centrin is a homolog of human centrin 2. immunofluorescence analysis localized the protein in t ...200111544261
the camp-binding proteins of leishmania are not the regulatory subunits of camp-dependent protein kinase.the most commonly used method to determine the camp binding activity in cytosolic extracts of promastigotes of leishmania spp. underestimated by approximately 11.5-fold the total amount of [(3)h]camp bound, when compared with results obtained by the modified millipore filter technique. three camp-binding proteins (bpi, bpii and bpiii) were partially purified and characterized. the native molecular masses of bpi, bpii and bpiii were estimated to be 105, 155 and 145 kda, respectively. the binding ...200111544092
structural analysis of adenine phosphoribosyltransferase from saccharomyces cerevisiae.adenine phosphoribosyltransferase (aprtase) is a widely distributed enzyme, and its deficiency in humans causes the accumulation of 2,8-dihydroxyadenine. it is the sole catalyst for adenine recycling in most eukaryotes. the most commonly expressed aprtase has subunits of approximately 187 amino acids, but the only crystal structure is from leishmania donovani, which expresses a long form of the enzyme with 237 residues. saccharomyces cerevisiae aprtase was selected as a representative of the sho ...200111535055
qsar study on the contribution of log p and e(s) to the in vitro antiprotozoal activity of glutathione derivatives.a series of n-s-blocked glutathione monoester and diester derivatives based on n-benzyloxycarbonyl-s-(2,4-dinitrophenyl)glutathione were evaluated for activity against the pathogenic parasites trypanosoma brucei brucei, trypanosoma cruzi, and leishmania donovani in vitro.only monoesters 7-9 with a log p value of >2.7 were active inhibitors of t.b. brucei bloodstream form trypomastigotes. diester compounds 10-15 and 17-27 in most cases were better inhibitors of t.b. brucei than monoester compound ...200111520206
effect of testosterone on leishmania donovani infection of macrophages. 200111511007
cloning, expression and antigenicity of the l. donovani reductase.the protozoan parasite leishmania undergoes a morphological and biochemical transformation from the promastigote to the amastigote form during its life cycle, which is reflected in the expression of stage-specific proteins. one of these proteins shows homology to a superfamily of reductase proteins. we have cloned the reductase gene from l donovani and have shown that it differs in only one nucleotide from the l. major homologue, resulting in one amino acid change. a cytosine (c) to guanine (g) ...200111506479
treatment of visceral leishmaniasis with sterically stabilized liposomes containing camptothecin.the efficacy of 20(s)-camptothecin (cpt), free and incorporated into sterically stabilized liposomes, has been investigated in vitro against leishmania donovani promastigotes and in vivo in a murine model of visceral leishmaniasis. incubation of l. donovani promastigotes with free or liposomal cpt inhibited the growth of parasites in a dose-dependent manner. tissue distribution studies revealed that the intraperitoneal administration of liposomal cpt was efficient for the delivery of high drug l ...200111502539
occurrence of leishmania donovani parasitemia in plasma of infected hamsters.intracardiac transfusion of plasma, mononuclear cell fraction and blood of infected hamster donors induced visceral leishmaniasis in normal hamster receptors. at the moment of transfusion, the donors already showed all the typical signs of the disease: ascites, cachexia, as well as splenomegaly and a high parasite load in the spleen and liver. all transfused hamsters developed typical visceral leishmaniasis between 90 and 120 days, indicating that all blood products were infectious. transfusion ...200111495646
studies on stibanate resistant leishmania donovani isolates of indian origin.studies with 26 clones of l. donovani promastigotes derived from three different indian isolates indicated that wild type parasites are mixture of stibanate sensitive and resistant cells. both forms of the parasite were resistant to the drug. infection with resistant parasites appears to be the primary reason of high rate of pentavalent antimony unresponsiveness among indian kala-azar patients. it was observed that the resistant parasites originated as a result of irregular and often incomplete ...200111495284
in vitro and in vivo activity of new rhodium (iii) complexes against leishmania donovani.the activities of 17 new rhodium drug complexes were determined against leishmania donovani promastigotes. the five most active salts were selected: [rh(iii)(2-amino-6-ethoxybenzothiazole)(4)br(2)](+)br(-); [rh(iii)(2-bromothiazole)(4)(br)(2)](+)br(-); [rh(iii)(mefloquine)(4)(cl)(2)](+)cl(-); [rh(iii)(2-mepacrine)(4)(cl)(2)](+)cl(-), and [rh(iii)(oxamniquine)(4)(cl)(2)](+)cl(-), which induced growth-inhibition rates of more than 50% at 24 h of treatment and at the maximum dosage tested. the cyto ...200111490204
the antileishmanial properties of surface-modified, primaquine-loaded nanocapsules tested against intramacrophagic leishmania donovani amastigotes in vitro. 200111487374
post-kala-azar dermal leishmaniasis with an atypical presentation. 200111476117
cutaneous leishmaniasis in an italian woman: case report.leishmaniasis is a sandfly-borne disease caused by a protozoan. the typical lesion of cutaneous leishmaniasis first appears as an erythematous papule at the site of inoculation, increases slowly in size, develops raised borders, and eventually ulcerates. the pentavalent antimony compounds continue to be a mainstay of therapy. we describe an italian patient with an enlarging facial plaque that was found to be caused by leishmania and discuss the toxicity associated with therapy.200111475954
effect of large targeted deletions on the mitotic stability of an extra chromosome mediating drug resistance in leishmania.a mitotically stable linear extra chromosome obtained in a leishmania donovani strain rendered mycophenolic acid-resistant has been physically mapped. this 290-kb chromosome has an inverted duplicated structure around a central inversion region, and is derived from a conservative amplification event of a approximately 140-kb subtelomeric end of chromosome 19. large-sized targeted deletions of the central region were performed through homologous recombination using three specific transfection vec ...200111470881
molecular analyses of old world leishmania rapd markers and development of a pcr assay selective for parasites of the l. donovani species complex.three amplicons, appearing in a species-specific manner on the electrophoregrams of rapd reactions that were obtained with primer opa1, opa1-800, opa1- 900, and opa1-1200, are analyzed in this study. the study revealed that each of these products is composed of one leishmania dna band, taxonomically conserved among the different old world species studied. subsequently, only the electrophoretic position of the rapd products can be considered species-specific. in addition, sequence data, genomic o ...200111465992
a unique surface membrane anchored purine-salvage enzyme is conserved among a group of primitive eukaryotic human pathogens.previously, we isolated and characterized the gene encoding the 3'-nucleotidase/nuclease (ld3'nt/nu) from the human pathogen, leishmania donovani. this unique cell surface enzyme has been shown to be involved in the salvage of host-derived purines, which are essential for the survival of this important protozoan parasite. in this report, we assessed whether the 3'-nucleotidase/nuclease was conserved amongst other pathogenic leishmania and related trypanosomatid parasites. results of pulsed field ...200111451370
leishmania donovani p36(lack) dna vaccine is highly immunogenic but not protective against experimental visceral leishmaniasis.the acquisition of immunity following subclinical or resolved infection with the intracellular parasite leishmania donovani suggests that vaccination could prevent visceral leishmaniasis (vl). the lack (leishmania homolog of receptors for activated c kinase) antigen is of interest as a vaccine candidate for the leishmaniases because of its immunopathogenic role in murine l. major infection. immunization of mice with a truncated (24-kda) version of the 36-kda lack antigen, delivered in either pro ...200111447143
malnutrition alters the innate immune response and increases early visceralization following leishmania donovani infection.malnutrition is a risk factor for the development of visceral leishmaniasis. however, the immunological basis for this susceptibility is unknown. we have developed a mouse model to study the effect of malnutrition on innate immunity and early visceralization following leishmania donovani infection. three deficient diets were studied, including 6, 3, or 1% protein; these diets were also deficient in iron, zinc, and calories. the control diet contained 17% protein, was zinc and iron sufficient, an ...200111447142
transcriptome meets metabolome: hierarchical and metabolic regulation of the glycolytic pathway.the fact that information flows from dna to rna to protein to function suggests that regulation is 'hierarchical', i.e. dominated by regulation of gene expression. in the case of dominant regulation at the metabolic level, however, there is no quantitative relationship between mrna levels and function. we here develop a method to quantitate the relative contributions of metabolic and hierarchical regulation. applying this method to the glycolytic flux in three species of parasitic protists, we c ...200111445079
leishmania donovani lipophosphoglycan causes periphagosomal actin accumulation: correlation with impaired translocation of pkcalpha and defective phagosome maturation.lipophosphoglycan (lpg) is the major surface glycoconjugate of leishmania donovani promastigotes. the repeating disaccharide-phosphate units of lpg are crucial for promastigote survival inside macrophages and establishment of infection. lpg has a number of effects on the host cell, including inhibition of pkc activity, inhibition of nitric oxide production and altered expression of cytokines. lpg also inhibits phagosomal maturation, a process requiring depolymerization of periphagosomal f-actin. ...200111437830
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