Publications

TitleAbstractYear(sorted ascending)
Filter
PMID
Filter
efficacy of some drugs on leishmania donovani in the golden hamster, mesocricetus auratus.the therapeutic and prophylactic effect of dehydroemetine and pentostam on leishmania donovani in experimentally infected golden hamsters (mesocricetus auratus) have been investigated. the intracardially infected hamsters with l. donovani and treated with dehydroemetine showed significantly lower weights in liver and spleen, and less in spleen length than those treated with pentostam. dehydroemetine and pentostam failed to provide these animals with any protection against experimental infection ...19816110518
infectivity of leishmania donovani primary culture promastigotes for golden hamsters. short communication. 19816111921
lethal effect of phenothiazine neuroleptics on the pathogenic protozoan leishmania donovani.phenothiazine drugs, which are widely used for their antipsychotic, antianxiety, and antiemetic effects, have been found to have protozoacidal effects on the human pathogen leishmania donovani. these compounds are lethal to both the extracellular stage of the organism, which is inoculated into humans by the sand fly, and the intracellular stage, which is found solely in human macrophages during established infection.19826124040
leishmaniasis in beige mice.the courses of two protozoal diseases, cutaneous and visceral leishmaniasis, were examined in three groups of c57bl/6j mice. one group of mice was homozygous recessive for the beige gene (bg/bg). beige mice are the genetic homologue of the human chédiak-higashi syndrome and, among other defects, are profoundly deficient in natural killer cell activity. wild-type (+/+) mice, which respond to experimental cutaneous or visceral leishmaniasis by eventually eliminating their parasites, and heterozygo ...19826218091
cell-mediated immune response in experimental visceral leishmaniasis. ii. oxygen-dependent killing of intracellular leishmania donovani amastigotes. 19826282967
a role for oxygen-dependent mechanisms in killing of leishmania donovani tissue forms by activated macrophages.leishmania donovani, the causative agent of visceral leishmaniasis, infects macrophages (m phi ) of susceptible vertebrates. immunologically activated m phi are leishmanicidal, but the mechanisms involved in the killing process are not well defined. we sought to investigate the role of reactive oxygen intermediates in the killing of l. donovani. both the free-swimming promastigote and the intracellular amastigote forms were found to be susceptible to killing in vitro by hydrogen peroxide and oth ...19826282971
oxidant-mediated damage of leishmania donovani promastigotes.dissemination of leishmania within the host is related to parasites undergoing unchecked proliferation. we therefore studied the effects of oxidant generating systems on promastigote multiplication by (i) direct determinations of organism proliferation and (ii) the incorporation of [3h]uracil into promastigote nucleoprotein. these two parameters correlated closely as measures of organism replication as demonstrated by parallel suppression of them by the protein synthesis inhibitors puromycin and ...19826284640
pretreatment with phorbol myristate acetate inhibits macrophage activity against intracellular protozoa.to further document the role of toxic oxygen intermediates in mononuclear phagocyte antiprotozoal activity, microbicidal macrophages were depleted of the capacity to generate superoxide anion (o-2) and hydrogen peroxide (h2o2) by pretreatment with phorbol myristate acetate (pma), a soluble agent which triggers the macrophage respiratory burst. treating cells for 90 min with 200 ng/ml of pma inhibited the extracellular release of both o-2 and h2o2 by 90% upon subsequent restimulation with either ...19826288939
adenylosuccinate synthetase and adenylosuccinate lyase from trypanosoma cruzi, specificity studies with potential chemotherapeutic agents.adenylosuccinate (succino-amp) synthetase and succino-amp lyase isolated from epimastigotes of trypanosoma cruzi by chromatography on phosphocellulose. the synthetase was capable of catalyzing the condensation of aspartic acid with imp and several imp analogs. the reaction with allopurinol ribonucleotide is of potential chemotherapeutic interest. this analog was slowly converted to its corresponding succino-amp analog with a km' of 140 micrometers (cf. imp at 10 micrometers) and a vmax' of 0.3 p ...19827037007
purine and pyrimidine salvage pathways in leishmania donovani.leishmania donovani, grown in culture, salvaged radiolabeled purine bases which were distributed into adenine and guanine ribonucleotides and into the rna of these cells. de novo synthesis of purines in l. donovani does not occur [j. j. marr, r. l. berens and d. j. nelson, biochim. biophys. acta 544, 360 (1978)]. [8-14c]adenine was rapidly deaminated to hypoxanthine via the action of an adenine aminohydrolase (ec 3.5.4.2). [8-14c]guanine was also rapidly deaminated by guanase (ec 3.5.4.3) to for ...19827059364
metabolism of 1-0-[1'-14c]octadecyl-sn-glycerol in leishmania donovani promastigotes. ether lipid synthesis and degradation of the ether bond.a long-chain 0-alkylglycerol, 1-0-[1'-14c]octadecyl-sn-glycerol, was taken up and metabolized extensively in leishmania donovani promastigotes grown on a lipid-free, semi-defined medium as well as on a lipid-free, synthetic medium in nearly identical ways. cleavage of the ether bond was the main event even after short incubation times (1 h) and low precursor concentration (2 microm), as judged from the appearance of radioactive acyl moieties residing mainly in phosphatidylcholine. in addition, l ...19827078578
cell-mediated immune response in experimental visceral leishmaniasis. i. correlation between resistance to leishmania donovani and lymphokine-generating capacity. 19827086136
killing of leishmania donovani. amastigotes by murine macrophages. 19827090913
genetics of resistance to infection with special reference to leishmaniasis. introduction, and genetics of susceptibility to leishmania donovani. 19827101398
failure of the phagocytic oxidative response to protect human monocyte-derived macrophages from infection by leishmania donovani. 19827108206
identification and partial characterization of an extracellular acid phosphatase activity of leishmania donovani promastigotes.an extracellular acid phosphatase was detected in the growth media of leishmania donovani promastigotes. the enzyme was released at all stages of the growth cycle and in amounts which accounted for 90% of the total amount of this enzyme in the culture. the exoenzyme exhibited a ph optimum of 4.5 to 5.0 and was active with a variety of organic phosphates. the enzymatic activity was excluded from sephacryl s-300 and was retained by ultrafilters with nominal molecular weight cutoffs of up to 300,00 ...19827110130
cell surface origin of antigens shed by leishmania donovani during growth in axenic culture.antisera against isolated cell surface preparations (pcsp-as) of leishmania donovani promastigotes were used to detect extracellular antigens produced during the growth of these organisms in four different growth media. the pcsp-as precipitated two major antigenically identical but electrophoretically distinct components, in addition to several minor antigens. immunoelectrophoretic studies employing pcsp-as, pcsp-as absorbed with intact, live promastigotes, and pcsp-as absorbed with a major extr ...19827118250
[experimental transmission of the causative agent of visceral leishmaniasis, leishmania donovani, to golden hamsters by phlebotomus longiductus, parr. 1928 and phlebotomus smirnovi, perf. 1941 sandflies]. 19827121405
partial purification and characterization of particulate acid phosphatase of leishmania donovani promastigotes.1. more than 90% of the total acid phosphatase activity in a sonicate of l. donovani promastigotes is contained in a particulate fraction (200,000 x g 30 min). the enzyme can be quantitatively extracted and solubilized with the aid of triton x-100 (0.2 g/100 ml) and purified over 200-fold with 54% yield by chromatography on deae-sephadex, qae-sephadex, sepharose 4b and concanavalin-a sepharose. 2. the phosphatase is a true acid hydrolase (ph optimum, 5.0-5.5) and has a rather broad substrate spe ...19827128111
protective effect of glucan against visceral leishmaniasis in hamsters.the effect of pre- or posttreatment with glucan, a reticuloendothelial stimulant, on the course of leishmania donovani infection was assessed in highly susceptible hamsters. intravenous administration of glucan before or after l. donovani infection significantly suppressed proliferation of amastigote-stage parasites in liver and spleen. glucan-activated peritoneal macrophages in vitro also significantly reduced multiplication of the intracellular parasite. ultrastructural studies revealed a well ...19827129637
pathogenesis of anaemia in hamsters infected with leishmania donovani.the development of anaemia was studied in hamsters infected with leishmania donovani. haematocrit studies as well as erythrocyte survival studies using radioactive chromium (51cr), gave evidence of a progressive anaemia during the course of infection. the erythrocytes were positive in direct antiglobulin tests using antisera to igg and complement c3. moreover, erythrophagocytosis as well as increased deposits of haemosiderin in the liver and the spleen, particularly in the areas of proliferating ...19827136193
ultrastructure of amastigotes of leishmania donovani in the bone marrow of a dog.visceral leishmaniasis was diagnosed in a dog which had been in spain for 4 years before being brought to florida. a bone marrow aspirate from the dog was examined by electron microscopy. phagocytized amastigotes by macrophages had an electron-dense plasma membrane and contained ribosomes, rough endoplasmic reticulum, a well-developed golgi apparatus, an intracellular flagellum, lipid, a kinetoplast, a row of microtubules immediately beneath the cell membrane, and a nucleus with marginated chrom ...19827149419
the metabolism of formycin b in leishmania donovani. 19827150292
host-parasite relationship in murine leishmaniasis: pathophysiological and immunological changes.the host-parasite relationship in human visceral leishmaniasis remains poorly understood. in the present study, pathophysiological and immunological changes were examined in balb/c mice infected with leishmania donovani. these animals developed chronic infection with massive hepatosplenomegaly and hypergammaglobulinemia. in contrast to mice inoculated with 0.8 x 10(6) or 4 x 10(6) amastigotes, mice infected with 20 x 10(6) amastigotes failed to reduce liver parasite loads during 2 to 8 weeks of ...19827152667
an easily prepared two phase medium for cultivation of leishmania donovani. 19827153479
[comparative study of the antigenic properties and virulence of leishmania clones (trypanosomatidae, leishmania)].a relation between antigenic properties and virulence of leishmania clones were studied. the clones were obtained from a naturally infected sandfly (phlebotomus of the group caucasicus) caught in the burrow of great gerbil in turkmenia. antigenic properties of the clones were studied by means of adler's test (safjanova's modification); the virulence of the clones was studied on golden hamsters by means of standard technique. there was revealed heterogenicity of the phlebotomus strain of leishman ...19827155626
guanosine 5'-monophosphate reductase from leishmania donovani. a possible chemotherapeutic target.gmp reductase was highly purified from promastigotes of leishmania donovani by chromatography on a single deae-cellulose column. bimodal substrate saturation curves resulted in a 1/v versus 1/[gmp] plot that curved downward above 40 microm gmp. the kinetic constants were, therefore, obtained with gmp below this concentration. the k'm for gmp was 21 microm at ph 6.9. the enzyme was very sensitive to activation by gtp. at 20 microm gmp, a maximum of 600% activation occurred at 100 microm gtp. half ...19827159467
leishmaniasis in brazil: xviii. further evidence incriminating the fox cerdocyon thous (l) as a reservoir of amazonian visceral leishmaniasis.major endemic areas of visceral leishmaniasis in brazil are located in the drier, poorly forested regions, principally in the northeastern states such as ceará and bahia. cases of the human disease in the amazon region are rare, very sporadic, and seldom present opportunities for epidemiological study. following the report of a fatal case near salvaterra, the island of marajó, pará state, a preliminary investigation has resulted in the isolation of a parasite regarded as leishmania donovani chag ...19827164150
incorporation of [1-14c]acetate into fatty acids and aliphatic moieties of glycerolipids in leishmania donov ani promastigotes.1. short-time incubations (20-300 sec) of leishmania donovani with [1-14c] acetate showed lauric, myristic and palmitic acid to be labeled first, whereas from 150 sec on the radioactivity was mainly found in stearic and oleic acid. 2. after an incubation period of 7 days the distribution of radioactivity in fatty acids was similar to the mass distribution of fatty acids. 3. up to 300 sec 14c-activity was present mainly in acyl moieties of lipids (94%). 4. ether moieties of radylglycerols, dirady ...19827172630
the effect of inhibitors on the respiration of leishmania donovani promastigotes from culture. 19827173076
growth factor requirements for in vitro growth of leishmania donovani. 19827174005
isolation and partial characterization of antigen from leishmania donovani promastigotes and its possible use in serodiagnosis. 19827174006
temperature-dependent fatty acyl group changes in phospholipids of 37 c-adapted leishmania donovani promastigotes. 19827175608
sensitization of offspring of leishmania donovani-infected hamsters to immunization and of offspring of immunized hamsters to challenge.female hamsters, infected intracardially (i.c.) with 1.0--2.0 x 10(5) amastigotes of leishmania donovani produced offspring, following mating, which, when immunized subcutaneously with 1.0 x 10(7) amastigotes at 8 weeks of age, were more resistant to i.c. challenge 6 weeks later than were hamsters born to non-infected mothers. offspring of mothers infected with as many as 6.0 x 10(6) amastigotes demonstrated no greater capacity for immunization than did those of mothers infected with 1.0 x 10(5) ...19827201750
inbred mouse strain resistance to mycobacterium lepraemurium follows the ity/lsh pattern.inbred mouse strains and their f1 hybrids infected intravenously with mycobacterium lepraemurium showed different mean survival times (mst). balb/c and c57bl mice were particularly susceptible, whereas c3h, cba and dba/2 mice were relatively resistant. resistance as judged by mst was dominant in the f1 hybrids. a similar ranking order was obtained by comparing the doubling time of the bacillus in the bone marrow, the increase in spleen weight between 4 and 12 weeks after infection, and the patho ...19826749659
polyclonal b cell activation in hamsters infected with parasites of the genus leishmania.mesocricetus auratus (golden hamsters) infected with leishmania developed characteristic b cell immune responses that depended on the infecting species of leishmania. thus, hamsters infected with viscerotropic leishmania (leishmania donovani) developed antileishmania antibodies and hypergammaglobulinemia due to polyclonal activation of b cells as measured by reverse hemolytic plaque assay. in contrast, dermotropic leishmanias (l. braziliensis braziliensis and l. mexicana amazonensis) stimulated ...19826759410
immune complexes in indian kala-azar.patients with indian kala-azar were investigated for the presence of circulating immune complexes by the platelet aggregation test, complement deviation test, and polyethylene glycol precipitation test. circulating antibodies were tested by the conventional indirect immunofluorescence test using leptomonad forms of leishmania donovani and crithidia luciliae. the serum complement level (c3) was measured using the mancini technique. the results indicate that a large number of patients with indian ...19826761008
dot enzyme-linked immunosorbent assay (dot-elisa): a micro technique for the rapid diagnosis of visceral leishmaniasis.a micro enzyme-linked immunosorbent assay utilizing antigen dotted onto nitrocellulose filter discs (dot-elisa) was developed for the rapid diagnosis of visceral leishmaniasis. leishmania donovani promastigotes applied to filter discs in volumes of 1 microliter were placed in 96-well microtiter plates, blocked with bovine serum albumin, then incubated with 4-fold dilutions of patient sera. after incubation with peroxidase-conjugated anti-human antibody, washing and addition of precipitable subst ...19836549606
immunization of mice against leishmania donovani by subcutaneous injections of dead promastigotes.mice immunized by a series of intravenous, intraperitoneal or subcutaneous injections of formalin-killed leishmania donovani promastigotes with glucan, a beta 1, 3 polyglucose, exhibited a significant degree of resistance against subsequent infection with viable promastigotes. intramuscular immunization was not effective. immunization via subcutaneous injections of dead promastigotes simultaneously with glucan elicited protective resistance, positive skin test responsiveness before and after cha ...19836824127
synthesis and antileishmanial activity of 6-methoxy-4-methyl-n-[6-(substituted-1-piperazinyl)hexyl]-8-quinolinamines and related compounds.the 8-quinolinamine, 4-[6-[6-methoxy-4-methyl-8-quinolinyl)amino]hexyl]-1-piperazineethanol (1b), has been shown to be highly effective against leishmania donovani infections in hamsters. in an effort to obtain a more potent, less toxic 8-quinolinamine, a series of analogues (2) was prepared that examined particularly the structural requirements of the terminal piperazine moiety. of the substituted piperazines and alternative heterocycles prepared, as well as those quinoline analogues with ring ...19836827535
interaction of leishmania donovani promastigotes with human phagocytes.leishmania donovani is an important intracellular protozoal pathogen of humans, which resides solely within mononuclear phagocytes. phase-contrast microscopy and cinemicroscopy were used to examine the interaction of l. donovani promastigotes with human phagocytes to characterize and quantitate the sequence of events that results in leishmanial infection.19836832834
comparison of microscopy and culture in the detection of leishmania donovani from splenic aspirates.three culture media were compared with giemsa-stained smears for the detection of leishmania in splenic aspirates from kenyan patients with visceral leishmaniasis. ninety-nine splenic aspirates obtained from 26 patients at various times before, during, and after treatment were cultured in schneider's drosophila medium and rpmi medium 1640 (each supplemented with 20% fetal bovine serum) and mcconnell's modification of senekje's medium overlayed with 0.9% saline. from 13 splenic aspirates obtained ...19836837840
leishmania tropica and leishmania donovani: solid phase radioimmunoassay using leishmanial excreted factor.a radioimmunoassay for the quantitative determination of anti-leishmanial excreted factor (ef) antibody in rabbit sera was developed. the assay, using leishmania tropica and leishmania donovani promastigotes ef, purified by either extraction with phenol followed by fractionation on a sephadex g-100 column or by the dissociation of ef antibody complexes, was shown to be sensitive and reproducible. using monospecific anti-ef antibodies, levels of as low as 0.06-0.12 micrograms/ml of anti-ef igg co ...19836852165
immunogenicity of soluble and particulate antigens from leishmania donovani: effect of glucan as an adjuvant.the protective efficacy of glucan as an adjuvant with killed promastigotes of leishmania donovani was compared with that of soluble or particulate fractions of the parasite. when these vaccine preparations were injected either intravenously or subcutaneously in cf-1 mice, glucan potentiated resistance against l. donovani infections as reflected by significant reductions in hepatic amastigote counts relative to infected control mice. the leishmanial antigens alone afforded no protection. serum di ...19836852909
surface antigens of leishmania donovani promastigotes.surface antigen profiles of leishmania donovani promastigote isolates have been studied. surface patterns of brazilian and african isolates display remarkable similarities and are extremely simple, consisting of three major peptides of 65,000, 25,000, and 23,000 mol wt. surface iodination and biosynthetic labeling coupled to immunoprecipitation techniques revealed that a single major determinant of 65,000 mol wt is recognized in all strains by sera from kala-azar patients from both brazil and af ...19836854205
relative insensitivity of a kenyan strain of leishmania donovani to pentavalent antimony therapy in hamsters. 19836854484
regulation of leishmania populations within the host. v. resistance to l.donovani in wild mice.samples of wild mus musculus from two populations in areas endemic for leishmaniasis and from seven populations in non-endemic areas were found to be uniformly resistant when tested for their early response to leishmania donovani infection. males from one endemic and one non-endemic population were crossed to females from two inbred strains of mice carrying the susceptible allele for the innate resistance gene, lsh, on different genetic backgrounds. bimodality of liver parasite counts and a clos ...19836854699
quantitation of amastigotes of leishmania donovani in smears of splenic aspirates from patients with visceral leishmaniasis.during a 20-month period, more than 500 splenic aspirations were performed in 89 patients with suspected or proven visceral leishmaniasis. the two complications which occurred (intra-abdominal bleeding and penetration of the intestine in one patient each) both resolved with conservative management. parasite density in splenic aspirate smears was graded on a logarithmic scale from 0 (no parasites in 1,000 microscopic fields) to 6+ (greater than 100 parasites per microscopic field). among 46 newly ...19836859397
leishmania donovani infection in heterozygous and recombinant h-2 haplotype mice.on a b10 (lshs) genetic background the development of acquired t-cell-mediated immunity to leishmania donovani infection in mice is under h-2-linked genetic control. three phenotypic patterns of recovery were previously observed: "early cure" (h-2s, h-2r), "cure" (h-2b) and "noncure" (h-2d, h-2q, h-2f), with cure behaving as a recessive trait in h-2b/h-2d mice. in this study the long-term response to l. donovani is followed over 130 days of infection in eight recombinant haplotype strains and in ...19836604020
immunoprophylaxis against kala-azar. iv (b). immunization of golden hamsters against leishmania donovani. 19836609188
leishmania donovani: oral efficacy and toxicity of formycin b in the infected hamster.formycin b, a structural analog of inosine, was evaluated as an orally administrable antileishmanial agent. against leishmania donovani in hamsters, it achieved an 85-92% reduction in numbers of parasites in livers of infected animals after oral administration at 13 mg/kg/day for 4 days. its efficacy by oral administration was approximately four to eight times that by intramuscular administration and four times that of the positive control drug glucantime by intramuscular administration. the lev ...19836617804
differential survival of leishmania donovani amastigotes in human monocytes.leishmania donovani is an important intracellular protozoal pathogen of man; it is found solely within macrophages in its amastigote stage in humans, and exists in its extracellular, flagellated promastigote stage in the sandfly, its arthropod vector. to determine if either stage of l. donovani was capable of surviving within monocytes--the oxidatively active precursors of tissue macrophages--interactions of the parasite with human monocytes were studied in vitro. amastigotes and promastigotes w ...19836619546
leishmaniasis in brazil. xix: visceral leishmaniasis in the amazon region, and the presence of lutzomyia longipalpis on the island of marajó, pará state.sporadic cases of visceral leishmaniasis in amazonian brazil appear limited to pará state, in the lower amazon valley and principally near the atlantic coast. the fox cerdocyon thous (l.) has been incriminated as a natural host of the causative parasite, leishmania donovani chagasi, but past doubts have existed over the identification of the most likely vector as lutzomyia (lutzomyia) longipalpis (lutz & neiva, 1912). investigations on two of five recent cases of visceral leishmaniasis of man in ...19836623589
liposomal chemotherapy in visceral leishmaniasis: an ultrastructural study of an intracellular pathway.the intracellular fate of liposomes administered intracardially was examined in the liver and spleen of hamsters experimentally infected with leishmania donovani. separate groups of animals were treated with liposomes containing either an antileishmanial agent, a colloidal gold marker, or saline. ultrastructural examinations of lysosomal interactions with the parasitophorous vacuole and with phagocytized liposomes were made. lysosomes readily fused with the parasitophorous vacuoles but appeared ...19836624193
surface antigens on a kenyan strain of leishmania donovani. 19836628296
high efficiency plating method for leishmania promastigotes in semidefined or completely-defined medium.a simple technique, developed for the isolation of clones derived from single, promastigote cells of leishmania donovani and leishmania tropica, involved the use of semisolid agar. both species of leishmania promastigotes formed discrete colonies at high efficiency either in semidefined medium containing 10% fetal calf serum or in completely-defined medium lacking serum. visible colonies appeared between 8 and 14 days in growth medium containing 10% fetal calf serum. replacement of the fetal cal ...19836631633
non-specific and specific stimulation of resistance against leishmania donovani in c57bl/6 mice.stimulation by intravenous injections of glucan, a beta 1,3 polyglucose, provided a significant degree of resistance in mice against leishmania donovani. the response of c57bl/6 animals was dose-dependent. a single glucan injection before or after infection induced significant resistance but to a lesser degree than two or three injections. immunization by injections of formalin-killed promastigotes with glucan via the subcutaneous or intravenous routes provided greater resistance than glucan or ...19836638931
testicular amyloidosis in hamsters experimentally infected with leishmania donovani.thirty hamsters were inoculated intraperitoneally with leishmania donovani. testes were examined grossly and histologically by light and electron microscopy. progressive testicular atrophy developed. spermatogenic cells of the seminiferous tubules showed vacuolar degeneration and decreased in number leading to a total azoospermia in the final weeks of the pathological process. lymphoplasmocytic infiltrates with macrophages containing leishmanias appeared in the intertubular space. amyloid deposi ...19836639870
antiactin and antitubulin antibodies in canine visceral leishmaniasis.visceral leishmaniasis, a chronic and often fatal disease, is caused by the protozoan parasite leishmania donovani. both specific and nonspecific antibodies are produced in the course of the disease, and autoantibodies may be involved in pathogenesis. tubulin and actin have been found to be associated with l. donovani. to learn whether antiactin and antitubulin antibodies are present in visceral leishmaniasis, we tested sera from 263 infected dogs by enzyme-linked immunosorbent assay for antibod ...19836642639
cell-mediated immune response in indian kala-azar and post-kala-azar dermal leishmaniasis.cell-mediated immune (cmi) response in 16 indian kala-azar (ka) and 12 post-kala-azar dermal leishmaniasis (pkadl) patients was studied in detail by in vitro lymphocyte transformation experiments and by in vivo skin testing. peripheral blood lymphocytes of active ka patients failed to be stimulated by leishmania antigen. on the other hand, lymphocytes from a majority of the active ka patients could be stimulated by phytohemagglutinin. active ka patients also failed to show delayed type hypersens ...19836642649
effect of berberine chloride on leishmania donovani. 19836674161
immunoprophylaxis against kala-azar. iva. immunization of golden hamsters and hissar strain albino mice against leishmania donovani (an exploratory study). 19836677687
efficacy of combined immunostimulation and chemotherapy in experimental visceral leishmaniasis.a regimen of combined immunostimulation and chemotherapy for the elimination of leishmania donovani amastigotes was evaluated. an in vitro experimental model utilized cultured peritoneal macrophages from c57b1/6 mice infected with l. donovani tissue forms. partial or complete activation of macrophages as judged by killing of tumor cells significantly enhanced the efficacy of sodium antimony gluconate (pentostam). the quantity of drug required for elimination of parasites from immunostimulated ce ...19836301300
inefficacy of metronidazole in experimental infections of leishmania donovani, l. mexicana, and trypanosoma brucei brucei.metronidazole has been claimed in several earlier reports to be active in human cases of leishmaniasis and trypanosomiasis. its efficacy against the protozoa causing these diseases was tested in hamsters infected with leishmania mexicana or l. donovani, and in mice infected with trypanosoma brucei brucei. in separate experiments, hamsters were either inoculated intradermally into the nose with 5 million amastigotes of l. mexicana or intracardially with 10-30 million amastigotes of l. donovani, a ...19836305218
killing of intracellular leishmania donovani by human mononuclear phagocytes. evidence for oxygen-dependent and -independent leishmanicidal activity.human peripheral blood monocytes were cultivated for 1-30 d before assay for h2o2 release or challenge with leishmania donovani promastigotes (ldp) or amastigotes (lda). 1-d cells readily generated h2o2 in response to both phorbol myristate acetate triggering (1,013 +/- 58 nmol/mg protein . 90 min) and ldp ingestion, and killed 50% of ldp within 6 h, and 90% by 24 h. in contrast, the same cells released little h2o2 during lda ingestion, killed no lda at 6 h and less than 30% by 24 h, and support ...19836308049
evidence for distinct 5'- and 3'-nucleotidase activities in the surface membrane fraction of leishmania donovani promastigotes.a surface membrane fraction isolated from leishmania donovani promastigotes contained distinct 5'- and 3'-nucleotidase activities. these were distinguished from each other, and from a previously described surface membrane nonspecific acid phosphomonoesterase, on the basis of several properties. the 5'- and 3'-nucleotidases had p' optima of 6.5 and 8.5, respectively. in contrast to the 3'-nucleotidase, the 5'-nucleotidase was inhibited by both ammonium molybdate and fluoride ions; the latter indu ...19836308442
the effect of treatment of the associated disease on the development of amyloidosis in the experimental animal.thirty-five golden hamsters infected with leishmania donovani were treated with pentostam and followed up to determine the effect of treatment on the development of secondary amyloidosis. seventy untreated golden hamsters infected with l. donovani were followed up as controls to determine the pattern of development of secondary amyloidosis. amyloid developed in all animals treated and untreated. the treatment significantly prolonged the survival time, but did not inhibit the development of renal ...19836312004
a balb/c congenic strain of mice that carries a genetic locus (ityr) controlling resistance to intracellular parasites.balb/c.dba/2 idh-1b-ityr-pep-3b congenic mice were developed by introgressively backcrossing the idh-1b and pep-3b markers of dba/2 mice onto the balb/c pi mice. this introduced a 30-centimorgan chromosome 1 segment of dba/2 chromatin that contained the ityr gene. balb/c.dba/2 idh-1b-ityr-pep-3b mice were resistant to in vivo infections by salmonella typhimurium, mycobacterium bovis, and leishmania donovani.19836343242
the identification of kala-azar and the discovery of leishmania donovani. 19836345968
cell biology of host-parasite membrane interactions in leishmaniasis.molecular interactions at the host-parasite interface are crucial for the outcome of microbial infection, particularly in infection by intracellular parasites, such as leishmania donovani and leishmania mexicana, whose natural transmission begins with the delivery of the promastigote stage by the sandfly vector into the susceptible host. the ensuing event is intracellular parasitism of macrophages in the host by the amastigote stage. the establishment of this event in leishmaniasis must follow t ...19836357669
interleukin 2 deficiency in murine leishmaniasis donovani and its relationship to depressed spleen cell responses to phytohemagglutinin.this study examined the kinetics and mechanisms of depressed spleen cell responses to phytohemagglutinin (pha) that occur during leishmania donovani infection of balb/c mice. in co-culture experiments, neither spleen cells from infected animals nor parasite-infected macrophages suppressed pha responses of normal spleen cells. in addition, parasite-mediated suppression of pha-stimulated spleen cell proliferation could not be demonstrated. mice with 2 wk of infection did manifest an impairment in ...19836224858
immunoregulation of genetically controlled acquired responses to leishmania donovani infection in mice: the effects of parasite dose, cyclophosphamide and sublethal irradiation.on a b10 (lshs) genetic background, the development of acquired t cell mediated immunity to leishmania donovani infection in mice is under h-2 linked genetic control. following intravenous inoculation of 10(7) amastigotes three phenotypic patterns of recovery have been described: 'early cure' (h-2r,s), 'cure' (h-2b) and 'non-cure' (h-2d,q,f). in an attempt to determine the immunological basis for this h-2 linked genetic control the effects of varying parasite dose (5 x 10(3) to 5 x 10(7) amastig ...19836226920
immunofluorescent antibody test in american visceral leishmaniasis: sensitivity and specificity of different morphological forms of two leishmania species.this study was designed to determine which morphologic form and species of leishmania is most suitable for detection of antibody in sera from american visceral leishmaniasis (avl) patients by the indirect fluorescent antibody test (ifat). promastigotes and amastigotes of leishmania mexicana or leishmania donovani chagasi were used as sources of antigen. a total of 70 sera, including 30 from avl patients, 30 from healthy subjects and 10 from chagas' disease patients, were used in the study. titer ...19836407345
suppression of macrophage antimicrobial activity by a tumor cell product.medium conditioned by tumor cells (tcm) and certain nonmalignant cells contains a trypsin-sensitive factor that suppresses macrophage oxidative metabolism. because the killing of intracellular pathogens such as toxoplasma gondii and leishmania donovani by macrophages is largely oxygen-dependent, we tested the effect of tcm on the antiprotozoal activity of mouse peritoneal macrophages. after 24 hr of cultivation with tcm, in vivo and in vitro activated macrophages could no longer kill toxoplasmas ...19836408180
resistance to infection: looking for new genes.genetic factors in resistance to infection, somewhat neglected with the development of microbiology, are again receiving careful attention. although there are numerous reports of infection resulting from deficiencies in, for example, immunoglobulins or complement components, specific abnormalities in resistance associated with particular hla groups have been unexpectedly rare. in mice, the ity gene on chromosome 1, which is important in resistance to salmonella typhimurium infection, may well be ...19836409191
killing of intracellular leishmania donovani by lymphokine-stimulated human mononuclear phagocytes. evidence that interferon-gamma is the activating lymphokine.we have found that the crude lymphokines, which prime the human monocyte-derived macrophage to generate h2o2 and exert microbicidal activity against intracellular leishmania donovani, are rich in interferon (ifn)-gamma (600-3,000 u/ml). to determine the role of this specific lymphocyte product in macrophage activation, lymphokines were pretreated with a monoclonal antibody that neutralizes human ifn-gamma. antibody exposure completely abolished the capacity of both mitogen- and antigen-stimulate ...19836415111
uptake of promastigotes of a lizard leishmania sp. and leishmania donovani by mouse peritoneal macrophages. 19836134459
recognition of leishmania donovani antigens by murine t lymphocyte lines and clones. species cross-reactivity, functional correlates of cell-mediated immunity, and antigen characterization.studies in man and experimental animals suggest that cell-mediated immunity is of primary importance in limiting the pathogenesis of cutaneous and visceral leishmaniasis. in an attempt to determine, more directly, the role of t lymphocytes and the nature of the antigens that activate them, we have propagated antigen-specific murine t lymphocyte lines and clones that proliferate in response to antigens present on the membrane of intact leishmania donovani promastigotes. one such line cross-reacts ...19836193191
purine metabolism in leishmania donovani amastigotes and promastigotes.purine metabolism in leishmania donovani amastigotes was found to be similar to that of promastigotes with the exception of adenosine metabolism. adenosine kinase activity in amastigotes is approximately 50-fold greater than in promastigotes. amastigotes deaminate adenosine to inosine through adenosine deaminase, an enzyme not present in promastigotes. inosine is cleaved to hypoxanthine and phosphoribosylated by hypoxanthine-guanine phosphoribosyltransferase. promastigotes cleave adenosine to ad ...19836199667
splenic natural killer-cell activity in mice infected with leishmania donovani.several strains of inbred mice were infected with the protozoan parasite leishmania donovani, and, at several points during the infection, spleens of groups of these mice were tested for natural killer (nk)-cell activity vs lymphoma target cells in vitro and were evaluated for parasite burdens. generally, elevated followed by normal (compared to uninfected control mice) or subnormal nk responses occurred as the result of infection. elevated nk responses were not accompanied by high circulating l ...19846201286
biochemical genetic analysis of formycin b action in leishmania donovani.formycin b is cytotoxic toward leishmania and is a potential chemotherapeutic agent for leishmaniasis. in order to determine the mechanism of action of formycin b, we have isolated and characterized clonal populations of formycin b-resistant leishmania donovani. these formycin b-resistant clones are also cross-resistant to formycin a and allopurinol riboside-mediated growth inhibition. incubation of the formycin b-resistant cells with [3h]formycin b indicates that, unlike wild type cells, the re ...19846203896
mechanisms of depression of splenic natural killer cell function in c57bl/6 mice infected with leishmania donovani.c57bl/6 mice chronically infected with the protozoan parasite leishmania donovani exhibit profoundly depressed splenic natural killer (nk) cell activity as measured by in vitro cytolysis of lymphoma target cells. injection of infected mice with an interferon (ifn) inducer or in vitro treatment of infected splenocytes with ifn, a phorbol ester, or indomethacin failed to restore their nk activity to the degree shown by age-matched, uninfected mice. fractionation of infected splenocytes by nylon wo ...19846205773
mechanisms of acquired immunity in leishmaniasis.self-curing cutaneous leishmaniasis depends on t cell-mediated immune activation of infected macrophages. failure of immune control in inbred mouse models of metastasizing mucocutaneous and visceralizing forms of the disease involves, respectively, insusceptibility of the parasite and the generation of t cells that suppress a potentially curative response. prophylactic immunization in man has so far been restricted to cutaneous leishmaniasis and based on inducing infection under controlled condi ...19846151691
quantitative and ultrastructural studies on the uptake of drug loaded liposomes by mononuclear phagocytes infected with leishmania donovani.this study compared splenic and hepatic uptake of free and liposome-entrapped sodium antimony gluconate after i.v. administration to mice infected with leishmania donovani. it was demonstrated that entrapment within liposomes greatly altered the kinetics of uptake of the drug. we were also able to show that liposomes composed of sphingomyelin, stearylamine and cholesterol were marginally better than any other preparation in delivering entrapped drug to liver and spleen. x-ray microanalytical stu ...19846087139
leishmanial phosphatase blocks neutrophil o-2 production.leishmania donovani, the causative agent in kala-azar or visceral leishmaniasis, infects cells of the macrophage system. we show that a purified preparation of the tartrate-resistant acid phosphatase, isolated from the external surface of l. donovani promastigotes, inhibits superoxide anion production by human neutrophils. preincubation of neutrophils for 15-30 min at 37 degrees c with 240 units (1 unit equals 1 nmol of 4-methylumbelliferyl phosphate cleaved per h) of the acid phosphatase decrea ...19846088532
characterization of a mutant leishmania donovani deficient in adenosine kinase activity.from a mutagenized population of wildtype leishmania donovani promastigotes, a clonal cell line, tuba2, was isolated by virtue of its ability to survive and grow in 20 microm tubercidin (7-deazaadenosine). the tuba2 clone was also 1000-fold less sensitive than the parental line to growth inhibition by formycin a, another cytotoxic adenosine analog. parental and mutant cells, however, were equally sensitive to growth inhibition by formycin b, allopurinol riboside, and 6-thioguanosine. mutant cell ...19846090896
restriction endonuclease analysis of leishmania kinetoplast dna characterizes parasites responsible for visceral and cutaneous disease.the kinetoplast dna (kdna) from promastigotes of leishmania responsible for old and new world cutaneous and visceral disease was characterized to determine if species and strains causing similar or different diseases could be identified. restriction enzymes were used to digest kdna into fragments that were separated into characteristic banding patterns after electrophoresis in agarose or linear gradient polyacrylamide gels. hybridization was conducted with a 32p-kdna probe and kdna fragments tra ...19846091469
an in-vitro system for determining the activity of compounds against the intracellular amastigote form of leishmania donovani.a method has been defined for infecting primary mouse peritoneal macrophages with amastigotes of leishmania donovani in vitro, and analysing the response of the infected macrophages to treatment with drugs. the growth of intracellular amastigotes was inhibited by all clinically used antileishmanial drugs. toxic effects on macrophages were observed with some drugs. other experimental antileishmanial compounds were active in this system. this test is proposed as an initial screening test for the d ...19846096347
purine salvage enzymes in leishmania donovani and trichomonas vaginalis. 19846426255
arachidonic acid metabolism in murine leishmaniasis (donovani): ex-vivo evidence for increased cyclooxygenase and 5-lipoxygenase activity in spleen cells.this study examined the metabolism of arachidonic acid (20:4) by splenic mononuclear cells from balb/c mice infected with leishmania donovani. spleen cells removed from mice after either 4 or 8 weeks of infection and cultured in the presence of phytohemagglutinin (pha) incorporated 60-70% less [3h]thymidine and synthesized 2- to 5-fold more prostaglandin e2 than did spleen cells from normal mice. inhibition of cyclooxygenation by sodium meclofenamate was associated with restoration of pha-induce ...19846435888
evaluation of different subcellular fractions of leishmania donovani for immunodiagnosis of visceral leishmaniasis. 19846440858
immunoregulation of genetically controlled acquired responses to leishmania donovani infection in mice: demonstration and characterization of suppressor t cells in noncure mice.on a b10 genetic background, genes in the i region of h-2 influence the development of acquired t-cell mediated immunity to leishmania donovani infection in mice. in previous studies, noncure in h-2d mice could be abrogated by pretreatments with cyclophosphamide or sublethal irradiation. the prophylactic effect of these pretreatments was consistent with deletion of the precursors of suppressor t cells suppressing t-cell-mediated immune responses. in this study, cell transfer experiments provide ...19846231248
genetic analysis of nucleoside transport in leishmania donovani.genetic dissection of nucleoside transport in leishmania donovani indicates that the insect vector form of these parasites possesses two biochemically distinct nucleoside transport systems. the first transports inosine, guanosine, and formycin b, and the second transports pyrimidine nucleosides and the adenosine analogs, formycin a and tubercidin. adenosine is transported by both systems. a mutant, fbd5, isolated by virtue of its resistance to growth inhibition by 5 microm formycin b, cannot eff ...19846234454
leishmania chagasi and l. donovani: experimental infections in domestic cats.the susceptibility of domestic cats to visceral leishmaniasis was examined by inoculating cats with amastigotes of leishmania donovani and l. chagasi by the intravenous route, and with promastigotes of l. chagasi by the intradermal route. parasites were recovered from intravenously inoculated cats as long as 16 weeks after inoculation, but parasites apparently did not locate in the viscera in cats inoculated intradermally. parasites were not detected in intravenously inoculated cats killed at 24 ...19846479284
stage-specific variations in lectin binding to leishmania donovani.visceral leishmaniasis is caused by the dimorphic protozoan leishmania donovani, which exists as an aflagellar amastigote within mammalian mononuclear phagocytes and as a flagellated extracellular promastigote in its sandfly vector. we have identified four plant lectins that bind to the l. donovani surface, and through these we have documented stage-specific differences in exposed surface carbohydrates. concanavalin a bound to both promastigotes and amastigotes; binding was inhibited by mannose ...19846480103
glucose transport in leishmania donovani promastigotes.mid-log phase leishmania donovani promastigotes accumulated 2-deoxy-d-glucose (2-dog) via a carrier mediated transport system, maintaining an apparent km of 24.4 microm and a vmax of 3.12 nmol mg-1 protein min-1. d-glucose but not l-glucose competitively inhibited the 2-dog transport with an apparent ki of 18.7 microm. transport of 2-dog was inhibited by 2,4-dinitrophenol and nan3. the parasites maintained a 2-dog gradient of at least 79 fold across the surface membrane, demonstrating the active ...19846482908
immunodiagnosis of giardiasis by elisa and studies on cross-reactivity between the anti-giardia lamblia antibodies and some heterologous parasitic antigens and fractions.specific antibodies against giardia lamblia in 92 sera from asymptomatic carriers were investigated by elisa. using cyst antigen, antibodies were detected in 91 of the sera, by means of alkaline phosphatase-labelled antispecies immunoglobulin. the e/405nm values of the positive sera ranged between 0.350 and 1.700, whereas in the 78 control sera they were 0.270 +/- 0.220. cross-reactivity between the anti-g. lamblia antibodies and 18 heterologous parasitic antigens and fractions was also studied. ...19846486935
a study of the differential respiratory burst activity elicited by promastigotes and amastigotes of leishmania donovani in murine resident peritoneal macrophages.acridine orange and ethidium bromide and a combination of fluorescent and transmitted light microscopy used in conjunction with the qualitative nitroblue tetrazolium assay for superoxide anion (o2-) release demonstrated dramatic differences in the binding of and respiratory burst (rb) activity elicited by promastigotes and amastigotes of leishmania donovani in resident peritoneal macrophages (m phi) from c57bl/10scsn mice. when amastigotes were incubated with m phi for 30 min the number of paras ...19846490087
use of immunological manipulations in studying genetically controlled responses to leishmania donovani infection in mice. 19846493810
genetic analysis of adenine metabolism in leishmania donovani promastigotes. evidence for diploidy at the adenine phosphoribosyltransferase locus.mutant promastigotes of leishmania donovani deficient in adenine phosphoribosyltransferase (ap-rib transferase) have been isolated in medium containing 4-aminopyrazolopyrimidine. the generation of ap-rib transferase-deficient mutants occurred in two discrete steps. in the first step, clones were isolated with 50% of wild-type levels of ap-rib transferase activity. these cells were reselected, and colonies totally deficient in ap-rib transferase were isolated. wild-type and ap-rib transferase-def ...19846501311
Refresh
firstprev
12345678910...
nextlast
Displaying items 301 - 400 of 5301