| resistance to babesia spp. and plasmodium sp. in mice pretreated with an extract of coxiella burnetii. | mice injected intravenously with a commercially available extract of coxiella burnetii prepared for use as the antigen in the complement fixation diagnostic test for q fever were subsequently resistant to infection with babesia microti, babesia rodhaini, and plasmodium vinckei petteri. the parasites appeared to die inside circulating erythrocytes. protection was unaffected by exposing the pretreated mice to 900 rads on the day before they were infected. to explain these findings, it is postulate ... | 1979 | 378850 |
| new observations on the malaria parasites of rodents of the central african republic - plasmodium vinckei petteri subsp. nov. and plasmodium chabaudi landau, 1965. | the morphology and enzyme forms of malaria parasites isolated from 50 wild caught specimens of thamnomys rutilans from the central african republic have been studied and three distinct species of plasmodium identified. one species has been confirmed as plasmodium yoelii yoelii. morphological features of both the remaining species correspond to those given by landau (1965) in her original description of plasmodium chabaudi. for one of these species the name p. chabaudi has been retained; the othe ... | 1975 | 1155987 |
| plasmodium vinckei petteri: identification of the stages sensitive to arteether. | antimalarial activity of arteether, a derivative of artemisinin (qinghaosu) against blood-induced infections of the highly synchronous plasmodium vinckei petteri rodent species of malaria was evaluated in swiss mice. a single subcurative dose of arteether of 2.2 mg/kg body weight was injected subcutaneously to mice, either during the prepatent period or during the patent infection, when different stages of the parasitic cycle were present in the blood. it was shown that rings and young trophozoi ... | 1992 | 1493877 |
| [plasmodium vinckei petteri: various aspects of its sporogony and exoerythrocytic schizogony]. | a study of plasmodium vinckei peterri sporogony was performed by experimental infection of anopheles stephensi with gametocytes from infected mice. the study includes the description of the ookinete, complete evolution of oocysts and their final transformation to sporozoites. these were later used for intravenous infection of new mice, in order to study the exoerythrocytic schizogony. the morphology of exoerythrocytic schizonts was similar to that of other species of the same group. the minimal ... | 1991 | 1844972 |
| chronotherapy of malaria: identification of drug-sensitive stage of parasite and timing of drug delivery for improved therapy. | the cyclic nature of malarial fever in conjunction with the pharmacokinetic characteristics of antimalarial drugs, call for the conception of a chrono-therapeutic approach for the treatment of the disease. an experimental murine malarial model was devised using the highly synchronous species plasmodium vinckei petteri to test this rationale. sub-curative doses of chloroquine were injected sub-cutaneously to mice either during the prepatent period or during patent infection. inspection of the eff ... | 1991 | 1883151 |
| resolution of acute malarial infections by t cell-dependent non-antibody-mediated mechanisms of immunity. | while it is generally accepted that acute blood stage malarial infections are resolved through the actions of protective antibodies, we observed that resistance to acute infection with plasmodium chabaudi adami was mediated by t cell-dependent cellular immune mechanisms independent of antibody. we now report that acute blood stage infections caused by three additional murine hemoprotozoan parasites, plasmodium vinckei petteri, plasmodium chabaudi chabaudi, and babesia microti, appear to be contr ... | 1990 | 2387628 |
| experimental modifications of the circadian rythm of plasmodium vinckei petteri following cryopreservation; probable resistance of the merozoïte to thawing. | plasmodium vinckei petteri, in white mice, is a particularly useful strain for studies on the circadian rythm of plasmodium. an experimental model was set up: it showed that the rythm of asexual schizogony in the blood varies with the time and the mode of inoculation (cryopreserved blood or syringe passage). when frozen blood is injected, the time of schizogony depends on the time of injection; on the contrary, when the passage is by syringe from mouse to mouse, the rythm of schizogony is the sa ... | 1988 | 3142640 |
| the induction of tyrosine aminotransferase activity and its use as an indirect assay for endotoxin in mice infected with plasmodium vinckei petteri. | | 1982 | 6126456 |
| macrophages from babesia and malaria infected mice are primed for monokine release. | serum from mice infected with babesia microti or plasmodium vinckei petteri and given lipopolysaccharide (lps) contained appreciable amounts of tumour necrosis factor (tnf) and lymphocyte-activating factor (laf; interleukin i) activity. these monokines were not noted in serum from uninfected mice given the same dose of lps. this pattern was repeated when adherent peritoneal cells from normal or infected mice were exposed to lps in vitro and the supernatants assayed for laf. this indicates that t ... | 1984 | 6332293 |
| early lymphocyte trapping in malaria infections: a particulate antigen mediated phenomenon. | during the course of rodent malaria a marked decrease in the numbers of circulating lymphocytes within the peripheral blood occurred 2-4 days post-infection. monocytes and polymorphs did not show the same degree of decline. for both avirulent plasmodium yoelii and lethal plasmodium berghei infections lymphocyte numbers returned to control levels by day 6-8 post-infection. while these levels were maintained until clearance of p. yoelii infection, a sustained and abnormal increase occurred during ... | 1984 | 6387079 |
| effects of endotoxin on the histology of intact and athymic mice infected with plasmodium vinckei petteri. | apparently healthy intact and athymic mice with low to moderate parasitaemias of p. vinckei petteri are very susceptible to the harmful effects of endotoxin (lps). the histological changes seen in such mice after injection of a small dose of lps closely resemble those seen in mice terminally infected with this parasite. thus the onset of pathology could be hastened by giving a little lps. both groups of intact mice showed foci of hepatic necrosis, severe necrosis in the thymus, and light to mode ... | 1980 | 7000990 |
| failure of bacterial lipopolysaccharide to elicit a cytostatic effect on plasmodium vinckei petteri in c3h/hej mice. | malarial parasites, plasmodium vinckei petteri, taken from lipopolysaccharide (lps) high-responder (c3h/hejgifwehi) mice which had been injected 7 to 8 h previously with either escherichia coli lps b or lps w incorporated the purine nucleotide precursor hypoxanthine more slowly in an in vitro assay than parasites taken from saline-injected controls. in contrast, malarial parasites taken from lps low-responder c3h/hej mice after injection of either lps b or lps w did not show reduced levels of hy ... | 1982 | 7033142 |
| apparent irrelevance of nk cells to resolution of infections with babesia microti and plasmodium vinckei petteri in mice. | increased natural killer (nk) cell activity was found in the spleen and peritoneal cavity of mice infected with babesia microti or plasmodium vinckei petteri. this increased activity appeared not to be associated with the effectiveness of the host response against these parasites, since it reached its maximum when the parasitaemia was still low, and had decreased by the time the parasites reached peak densities. in addition mice pretreated with 89strontium of 17 beta-oestradiol experienced the s ... | 1982 | 7145462 |
| demonstration of a lipopolysaccharide-induced cytostatic effect on malarial parasites. | in an in vitro assay, malarial parasites (plasmodium vinckei petteri) taken from mice 7 to 8 h after the injection of bacterial lipopolysaccharide (lps) incorporated significantly less hypoxanthine into nucleic acid than did parasites from saline-treated controls. in contrast, incorporation was normal in parasites taken from mice within minutes of the injection of lps and in parasites cultured with lps. these results implied that the injection of lps induced the release of mediators with a cytos ... | 1981 | 7275307 |
| antimalarial effects of c18 fatty acids on plasmodium falciparum in culture and on plasmodium vinckei petteri and plasmodium yoelii nigeriensis in vivo. | following the demonstration of the antimalarial effect of the long chain saturated alcohol n-hentriacontanol ((ch2)29ch2oh), isolated from the bolivian endemic solanaceous plant cuatresia sp., we have tested the effect of the c18 fatty acids oleic, elaidic, linoleic, and linoleic on malaria parasites. these fatty acids inhibited the parasitemic development in mice infected with plasmodium vinckei petteri or with plasmodium yoelii nigeriensis in a 4-day suppressive test. to gain a deeper discernm ... | 1995 | 7628573 |
| stage sensitivity of plasmodium vinckei petteri to quinine, mefloquine, and pyrimethamine. | the stage-dependent sensitivity of plasmodium vinckei petteri to the antimalarial drugs quinine, mefloquine, and pyrimethamine was investigated using single subcurative doses and 2 different tests: a prepatency test evidencing the extension of the prepatent period according to the stage at which the drug was administered, and a patency test showing the morphological alterations of the parasites and the modifications of the parasitic pattern following drug treatment. quinine activity was maximal ... | 1995 | 7707210 |
| cell-mediated pathology during murine malaria-associated nephritis. | we have studied the cellular mechanisms involved in the development of nephritis during acute and chronic murine malaria infections induced by plasmodium vinckei petteri and p. berghei respectively. albuminuria and uraemia were observed during the early stages of both types of infection, and were associated with glomerular and interstitial hypercellularity. there was a gradual increase in numbers of cd45+ cells from the early stages of both infections onwards. these infiltrates contained cd4+ an ... | 1993 | 7902786 |
| the resolution of acute malaria in a definitive model of b cell deficiency, the jhd mouse. | because the role of cell-mediated immunity (cmi) in the resolution of blood-stage malaria remains unclear, we examined the question of whether mice completely lacking ab-mediated immunity (ami) but possessing some cmi can resolve experimental malaria previously reported not to require ami for resolution. severe combined immunodeficient mice reconstituted with enriched immune t cells (< 0.5% b220+ cells) suppressed acute plasmodium chabaudi adami parasitemia, suggesting that t, but not b, cells a ... | 1994 | 8157969 |
| in vivo antimalarial action of a lipophilic iron (iii) chelator: suppression of plasmodium vinckei infection by reversed siderophore. | we assessed in vivo antimalarial action of a lipophilic iron (iii) chelator belonging to a new synthetic family of biomimetic siderophores previously termed reversed siderophores (rsfs). the family member, rsf ileum2, was chosen for its high membrane permeability and fast irreversible inhibition of human malaria parasite growth in vitro. [shanzer a, et al., proc natl acad sci usa 88:6585, 1991 and lytton sd, et al., blood 81:214, 1993]. the lipophilic drug was administered to swiss mice by subcu ... | 1993 | 8352239 |
| the role of reactive nitrogen intermediates in modulation of gametocyte infectivity of rodent malaria parasites. | direct feeding of anopheles stephensi mosquitoes on mice infected with plasmodium vinckei petteri showed that, during the periods of schizogony in the blood, the infectivity of gametocytes was markedly reduced. this could be prevented by prior injection of the l-arginine analogue, nw-nitro-l-arginine (nwnla) showing that the altered infectivity was due to reactive nitrogen intermediates (rni). similar effects on transmission of p. yoelii nigeriensis were demonstrated in vitro by membrane feeding ... | 1993 | 8433851 |
| the effect of some 2-substituted quinolines isolated from galipea longiflora on plasmodium vinckei petteri infected mice. | we have evaluated the in vivo antiplasmodial activity of six 2-substituted quinolines and a total alkaloidal extract of galipea longiflora. balb/c mice infected with plasmodium vinckei petteri were treated orally at single dose of 50 mg/kg with quinolines or extract. contrary to the previous results obtained with the leishmania murine infection, 2-n-pentylquinoline showed activity against p. vinckei petteri. this result seems to confirm the antimalarial efficacy of infused stem bark of g. longif ... | 1996 | 8693048 |
| in vitro and in vivo inhibition of erythrocytic development of malarial parasites by docetaxel. | the stage-dependent susceptibility of plasmodium falciparum to a short exposure to docetaxel (taxotere) was evaluated by subjecting ring-infected, trophozoite-infected, and schizont-infected erythrocytes to a 5-h exposure to various concentrations of the drug. the schizont stage was shown to be the most sensitive stage; an inhibition of more than 60% of parasite development was observed at 10 nm. at this drug concentration, the development of the younger ring and trophozoite forms was unaffected ... | 1996 | 8834880 |
| carboxylic ionophores in malaria chemotherapy: the effects of monensin and nigericin on plasmodium falciparum in vitro and plasmodium vinckei petteri in vivo. | chloroquine is widely used in malaria chemotherapy. due to its weak base properties, this drug accumulates in the parasite food vacuole where it acts initially by raising the ph of this organelle, thereby reducing the digestion of hemoglobin by the parasite and preventing its growth. nevertheless, alkalinization of the food vacuole and inhibition of lysosomal protein degradation could also be achieved by means of carboxylic ionophores such as monensin and nigericin. these drugs intercalate into ... | 1996 | 8890952 |
| the gametocytes of plasmodium vinckei petteri, their morphological stages, periodicity and infectivity. | gametocyte production by p. vinckei petteri was cyclic, occurring at each schizogony every 24 h. they matured in 27 h from merozoite to type 0 microgametocyte, in 3 h from type 0 to type i, 6 h from type i to type ii and 3 h from type ii to type iii. transmission experiments showed that the time of maximum infectivity was midday when mice were inoculated at midnight, and midnight when mice were inoculated at midday. in all instances, maximum infectivity coincided with a peak in intensity by type ... | 1996 | 8982790 |
| characterization of the potent in vitro and in vivo antimalarial activities of ionophore compounds. | large-scale in vitro screening of different types of ionophores previously pinpointed nine compounds that were very active and selective in vitro against plasmodium falciparum; their in vitro and in vivo antimalarial effects were further studied. addition of the ionophores to synchronized p. falciparum suspensions revealed that all p. falciparum stages were sensitive to the drugs. however, the schizont stages were three- to ninefold more sensitive, and 12 h was required for complete parasite cle ... | 1997 | 9055986 |
| the chemotherapy of rodent malaria. liii. 'fenozan b07' (fenozan-50f), a difluorinated 3,3'-spirocyclopentane 1,2,4-trioxane: comparison with some compounds of the artemisinin series. | fenozan b07, a difluorinated 3,3'-spirocyclopentane, 1,2,4-trioxane, is a novel, second-generation antimalarial endoperoxide which is a potent blood schizontocide against strains of rodent malaria that are highly resistant to a wide spectrum of classical antimalarials. like compounds of the artemisinin series, its action is limited to the intra-erythrocytic stages, both asexual and sexual, and it is devoid of causal prophylactic activity. both fenozan b07 and the artemisinins are potent gametocy ... | 1997 | 9093426 |
| plasmodium yoelii nigeriensis: biological mechanisms of resistance to chloroquine. | the sensitivity to chloroquine according to the degree of synchronicity of plasmodium yoelii nigeriensis, which is considered to be the most resistant of the rodent malaria strains, was studied. the infection was synchronised by means of a percoll-glucose gradient which separates rings and young trophozoites from other stages. the mid-term trophozoite, when it predominated in the blood at the time of treatment, was shown to be as sensitive to chloroquine as plasmodium vinckei petteri. according ... | 1994 | 9140489 |
| the treatment of animal models of malaria with iron chelators by use of a novel polymeric device for slow drug release. | the hydrophilic desferrioxamine (dfo) and the lipophilic salicylaldehyde isonicotinoyl hydrazone (sih) are iron chelators which inhibit in vitro proliferation of plasmodium falciparum with similar potency (ic50 approximately 20 microm in 24- to 48-h tests). the in vivo assessment of these drugs was performed on swiss mice infected with plasmodium vinckei petteri with novel modes of drug administration and release. the drugs were delivered postpatently either by multiple i.p. injections or by a s ... | 1997 | 9190845 |
| killing of blood stage plasmodium vinckei petteri by spleen macrophages through l-arginine dependent mechanism. | a series of experiments was carried out to investigate the involvement of the l-arginine-dependent effector mechanism (ladem) in the killing of the blood stages of the rodent malaria parasite, plasmodium vinckei petteri, by activated spleen macrophages in vitro. p.v.petteri-infected red blood cells were co-incubated with spleen macrophages from normal mice which had previously received 10(8) mycobacterium bovis (bcg) 5 days earlier, in the presence of 0.1 microgram/ml lps with and without 0.1 mm ... | 1997 | 9561597 |
| optimisation of flow cytometric measurement of parasitaemia in plasmodium-infected mice. | mouse malaria is often used as a model for drug testing. the results of drug trials are monitored by tedious (and consequently, sometimes inaccurate) microscopic counting of blood smears, or by flow cytometry. we suggest an improved, accurate and time-saving flow cytometric method for determination of parasitaemias in mice infected with plasmodium vinckei petteri or plasmodium berghei. the method involves collection of drops of blood from the tail vein, fixation, storage, permeabilisation, stain ... | 2000 | 10779580 |
| a search for natural bioactive compounds in bolivia through a multidisciplinary approach. part iii. evaluation of the antimalarial activity of plants used by alteños indians. | a total of 40 plant extracts traditionally used by the alteños indians, a native community living between the andean block and the tropical valleys of bolivia, were screened for antimalarial activity in vitro on plasmodium falciparum chloroquine resistant (indo) strain, and in vivo on rodent malaria plasmodium vinckei petteri. eleven extracts displayed good or moderate activity in vivo, and ten extracts good or very good antimalarial activity in vitro. results of the screening are discussed here ... | 2000 | 10904155 |
| in vitro and in vivo potentiation of artemisinin and synthetic endoperoxide antimalarial drugs by metalloporphyrins. | the in vitro potentiation of artemisinin by synthetic manganese porphyrin complexes has been recently reported (f. benoit-vical, a. robert, and b. meunier, antimicrob. agents chemother. 43:2555-2558, 1999). since the activity of artemisinin and synthetic antimalarial endoperoxides is related to their interaction with heme (s. r. meshnick, a. thomas, a. ranz, c. m. xu, and h. z. pan, mol. biochem. parasitol. 49:181-190, 1991), an improvement of their efficiency may be expected in the presence of ... | 2000 | 10991867 |
| the effects of subcurative doses of chloroquine on plasmodium vinckei petteri gametocytes and on their infectivity to mosquitoes. | the effects of subcurative doses of chloroquine on rodent and human plasmodium transmission to the mosquito have been studied by several authors who showed a short-term (12 h) enhancement of gametocyte infectivity by the drug, restricted to chloroquine-resistant strains, and a long term (4-6 days) enhancement of gametocytogenesis of chloroquine-sensitive strains of plasmodium chabaudi. we investigated both short- and long-term effects of chloroquine on plasmodium vinckei petteri, a chloroquine-s ... | 2000 | 11027787 |
| susceptibility of species a, b, and c of anopheles culicifacies complex to plasmodium yoelii yoelii and plasmodium vinckei petteri infections. | the comparative susceptibilities of colonized species a, b, and c of anopheles culicifacies complex and anopheles stephensi were determined for 2 rodent malaria parasites plasmodium vinckei petteri and plasmodium yoelii yoelii. all the 3 members of the complex were found to support complete sporogony with varying success. controls, a. stephensi, become readily infected, with >70% developing oocysts. of the test groups, species a had the highest percentage of mosquitoes with oocysts (>25%) and sp ... | 2000 | 11191914 |
| inhibition of plasmodium yoelii blood-stage malaria by interferon alpha through the inhibition of the production of its target cell, the reticulocyte. | the effect of a recombinant hybrid human interferon alpha (ifn-alpha) (which cross-reacts with murine cells) on c57bl/6 mice infected with plasmodium yoelii sporozoites or parasitized erythrocytes was determined. ifn-alpha did not inhibit the development of the parasite in the liver, but it did reduce the blood parasite load and the hepatosplenomegaly induced by the infection in mice injected with blood-stage parasites. the extent of anemia in ifn-alpha-treated and control mice was similar, desp ... | 2001 | 11389041 |
| oestrus cycle perturbations and hypotrophy of clitoral glands in malaria-infected female balb/c mice. | an experimental host-parasite association involving balb/c female mice infected with plasmodium vinckei petteri was used with the aim of investigating the morphological and physiological alterations induced by the parasite in the genital tract of the host. the vaginal oestrous cycle was monitored as a daily clue to the sexual physiology of the female mice, and a complete histological analysis of the genital tract was performed 36 days following parasite inoculation. the oestrous cycle showed str ... | 2003 | 12489013 |
| potentiation of the antimalarial action of chloroquine in rodent malaria by drugs known to reduce cellular glutathione levels. | ferriprotoporphyrin ix (fp) is released inside the food vacuole of the malaria parasite during the digestion of host cell hemoglobin. fp is detoxified by its biomineralization to hemozoin. this process is effectively inhibited by 4-aminoquinolines. as a result fp accumulates in the membrane fraction and associates with enzymes of infected cells in parallel with parasite killing. free fp is degraded by reduced glutathione (gsh). this degradation is inhibited by chloroquine (cq) and amodiaquine (a ... | 2003 | 12948862 |
| host cell preference and variable transmission strategies in malaria parasites. | malaria and other haemosporin parasites must undergo a round of sexual reproduction in their insect vector in order to produce stages that can be transmitted to vertebrate hosts. consequently, it is crucial that parasites produce the sex ratio (proportion of male sexual stages) that will maximize the number of fertilization and thus, transmission to new vertebrate hosts. there is some evidence to show that, consistent with evolutionary theory, the sex ratios of malaria parasites are negatively c ... | 2005 | 15799947 |
| activity-guided isolation of antiplasmodial dihydrochalcones and flavanones from piper hostmannianum var. berbicense. | the bioassay-guided purification of an n-hexane extract from the leaves of piper hostmannianum var. berbicense led to the isolation of four monoterpene or prenyl-substituted dihydrochalcones (1a, 1b, 2, 3) as well as the known compounds 2',6'-dihydroxy-4'-methoxydihydrochalcone (4), linderatone (5), strobopinin (6), adunctin e (7) and (-)-methyllinderatin (8). their structures were established on the basis of nmr and x-ray analysis. (-)-methyllinderatin, linderatone and 2',6'-dihydroxy-4'-methox ... | 2007 | 17397884 |
| antimalarial activity of simalikalactone e, a new quassinoid from quassia amara l. (simaroubaceae). | we report the isolation and identification of a new quassinoid named simalikalactone e (ske), extracted from a widely used amazonian antimalarial remedy made out of quassia amara l. (simaroubaceae) leaves. this new molecule inhibited the growth of plasmodium falciparum cultured in vitro by 50%, in the concentration range from 24 to 68 nm, independently of the strain sensitivity to chloroquine. we also showed that this compound was able to decrease gametocytemia with a 50% inhibitory concentratio ... | 2009 | 19667291 |
| expression profile of prophenoloxidase-encoding (acppo6) gene of plasmodium vivax-refractory strain of anopheles culicifacies. | anopheles culicifacies is the main vector for transmission of plasmodium vivax malaria in the indian subcontinent. a strain of an. culicifacies isolated from its natural niche displayed complete refractoriness to p. vivax by melanotic encapsulation of ookinetes. prophenoloxidases are key components of the phenoloxidase cascade that leads to recognition and melanization of invading organisms. we isolated and cloned prophenoloxidase-encoding acppo6 gene of an. culicifacies and analyzed its express ... | 2010 | 21175075 |
| the in vivo anti-plasmodial activity of haliclonacyclamine a, an alkaloid from the marine sponge, haliclona sp. | the compound haliclonacyclamine a was isolated from the haliclona sponge at solomon islands. it acts as a powerful in vitro and in vivo anti-plasmodial agent against the chloroquine-resistant plasmodium falciparum strain fcb1and plasmodium vinckei petteri-infected mice, respectively. | 2011 | 21895455 |
| inference of the oxidative stress network in anopheles stephensi upon plasmodium infection. | ookinete invasion of anopheles midgut is a critical step for malaria transmission; the parasite numbers drop drastically and practically reach a minimum during the parasite's whole life cycle. at this stage, the parasite as well as the vector undergoes immense oxidative stress. thereafter, the vector undergoes oxidative stress at different time points as the parasite invades its tissues during the parasite development. the present study was undertaken to reconstruct the network of differentially ... | 2014 | 25474020 |
| comparative susceptibilities of species t and u of the anopheles fluviatilis complex to plasmodium vinckei petteri sporogony. | anopheles fluviatilis james is an important malaria vector in indian subcontinent. an. fluviatilis exists as a complex of three sibling species, of which two species, t and u, have been colonized so far. attempts were made to study the comparative susceptibility of species t and u of the an. fluviatilis complex to rodent malaria parasite plasmodium vinckei petteri by using anopheles stephensi liston as calibrator for variable infectivity in different isolates. an. stephensi, which was used as co ... | 2013 | 23802454 |