Publications
Title | Abstract | Year(sorted descending) Filter | PMID Filter |
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the a-domain and the thrombospondin-related motif of plasmodium falciparum trap are implicated in the invasion process of mosquito salivary glands. | sporozoites from all plasmodium species analysed so far express the thrombospondin-related adhesive protein (trap), which contains two distinct adhesive domains. these domains share sequence and structural homology with von willebrand factor type a-domain and the type i repeat of human thrombospondin (tsp). increasing experimental evidence indicates that the adhesive domains bind to vertebrate host ligands and that trap is involved, through an as yet unknown mechanism, in the process of sporozoi ... | 1999 | 10508153 |
effects of plasmodium berghei infection on cytochromes p-450 2e1 and 3a2. | metabolism and disposition of most drugs used to treat malaria are substantially altered in malaria infection. few data are available that specify effects of malaria infection on drug metabolism pathways in humans or animal model systems. in this report, studies were undertaken to determine the effect of plasmodium berghei infection on cytochrome p-450 (cyp450) 2e1 and 3a2-mediated metabolism and enzyme expression in rat liver microsomes. malaria infection (mal) resulted in significant decreases ... | 1999 | 10510746 |
iron acquisition by plasmodium spp. | 1999 | 10511692 | |
potentiation by febrifugine of host defense in mice against plasmodium berghei nk65. | the effect of febrifugine, the main alkaloidal constituent of an antimalarial crude drug, dichroa febrifuga lour., on protective immunity in mice infected with erythrocytic stage plasmodium berghei nk65 was investigated. febrifugine was administered orally, at a dose of 1 mg/kg/day, to mice before and/or after they were infected intraperitoneally with 2 x 10(6) parasitized red blood cells. then, mortality and the levels of parasitemia and plasma no3- [a degradation product of nitric oxide (no)] ... | 1999 | 10535750 |
gene gun intradermal dna immunization followed by boosting with modified vaccinia virus ankara: enhanced cd8+ t cell immunogenicity and protective efficacy in the influenza and malaria models. | in influenza and malaria, cd8+ t cells play an important role in protective immunity in mice. an immunization strategy consisting of dna priming followed by boosting with recombinant modified vaccinia virus ankara (mva) induces complete protection, associated with high levels of cd8+ t cells, against plasmodium berghei sporozoite challenge in mice. intradermal delivery of dna with a gene gun requires smaller amounts of dna than intramuscular injection, in order to induce similar levels of immune ... | 1999 | 10547421 |
ctrp is essential for mosquito infection by malaria ookinetes. | the malaria parasite suffers severe population losses as it passes through its mosquito vector. contributing factors are the essential but highly constrained developmental transitions that the parasite undergoes in the mosquito midgut, combined with the invasion of the midgut epithelium by the malaria ookinete (recently described as a principal elicitor of the innate immune response in the plasmodium-infected insect). little is known about the molecular organization of these midgut-stage parasit ... | 1999 | 10562534 |
conservation of a gliding motility and cell invasion machinery in apicomplexan parasites. | most apicomplexan parasites, including the human pathogens plasmodium, toxoplasma, and cryptosporidium, actively invade host cells and display gliding motility, both actions powered by parasite microfilaments. in plasmodium sporozoites, thrombospondin-related anonymous protein (trap), a member of a group of apicomplexan transmembrane proteins that have common adhesion domains, is necessary for gliding motility and infection of the vertebrate host. here, we provide genetic evidence that trap is d ... | 1999 | 10579715 |
targeted disruption of the plasmodium berghei ctrp gene reveals its essential role in malaria infection of the vector mosquito. | ctrp (circumsporozoite protein and thrombospondin-related adhesive protein [trap]-related protein) of the rodent malaria parasite plasmodium berghei (pbctrp) makes up a protein family together with other apicomplexan proteins that are specifically expressed in the host-invasive stage 1. pbctrp is produced in the mosquito-invasive, or ookinete, stage and is a protein candidate for a role in ookinete adhesion and invasion of the mosquito midgut epithelium. to demonstrate involvement of pbctrp in t ... | 1999 | 10587361 |
mutations in the cytochrome b gene of plasmodium berghei conferring resistance to atovaquone. | the molecular lesions which underlie the resistance of the malaria parasites to atovaquone, a coenzyme q analogue, were investigated. resistant clones of plasmodium berghei anka strain were isolated following prolonged propagation in mice in the presence of increasing doses of the drug, and their cytochrome b gene sequenced. three mutations were detected, t-c substitution at nt 431, g-a at nt 399 and g-t at nt 850, resulting in amino acid changes in the putative cytochrome b product at residues ... | 1999 | 10593174 |
a single-chain antibody fragment specific for the plasmodium berghei ookinete protein pbs21 confers transmission blockade in the mosquito midgut. | mouse monoclonal antibody 13.1 (mab 13.1) directed against pbs21, a 21-kda sexual-stage surface protein of plasmodium berghei, is known to inhibit oocyst development from gametocytes and ookinetes in the mosquito midgut. to examine the properties and potential uses of a single-chain antibody fragment (scfv) for blocking transmission of malaria parasites to mosquitoes, we have cloned and sequenced the genes encoding variable regions of the immunoglobulin heavy and light chains (v(h) and v(l)) of ... | 1999 | 10593175 |
the aspartic proteinase from the rodent parasite plasmodium berghei as a potential model for plasmepsins from the human malaria parasite, plasmodium falciparum. | the gene encoding an aspartic proteinase precursor (proplasmepsin) from the rodent malaria parasite plasmodium berghei has been cloned. recombinant p. berghei plasmepsin hydrolysed a synthetic peptide substrate and this cleavage was prevented by the general aspartic proteinase inhibitor, isovaleryl pepstatin and by ro40-4388, a lead compound for the inhibition of plasmepsins from the human malaria parasite plasmodium falciparum. southern blotting detected only one proplasmepsin gene in p. berghe ... | 1999 | 10601635 |
memory phenotype cd8(+) t cells persist in livers of mice protected against malaria by immunization with attenuated plasmodium berghei sporozoites. | natural exposure to plasmodium parasites induces short-lived protective immunity. in contrast, exposure to radiation-attenuated sporozoites (gamma spz) promotes long-lasting protection that is in part mediated by cd8(+) t cells that target exoerythrocytic stage antigens. the mechanisms underlying the maintenance of long-lasting protection are currently unclear. the liver is a repository of plasmodium antigens and may support the development and / or homing of memory t cells. while activated cd8( ... | 1999 | 10602007 |
are reactive oxygen species involved in the pathogenesis of murine cerebral malaria? | to investigate the involvement of oxidative tissue damage in the pathogenesis of murine cerebral malaria (cm), brain levels of protein carbonyls, 3,4-dihydroxyphenylalanine (dopa), o-tyrosine, and dityrosine were measured during plasmodium berghei anka (pba) and p. berghei k173 (pbk) infections. during pba infection in a cm model, brain levels of the substances were similar to those in uninfected mice. the role of phagocyte-derived reactive oxygen species in the pathogenesis of cm was examined i ... | 1999 | 9841842 |
treatment with liposome-bound recombinant human tumor necrosis factor-alpha suppresses parasitemia and protects against plasmodium berghei k173-induced experimental cerebral malaria in mice. | our study describes liposomes (conventional or sterically stabilized) as carrier systems for recombinant human tumor necrosis factor-alpha (rhtnf-alpha) to increase its protective efficacy against plasmodium berghei-induced experimental cerebral malaria (ecm) in mice. rhtnf-alpha was either covalently coupled to the outer surface of preformed liposomes or encapsulated into the liposomes. for coupling to the liposomes, reactive thiol groups were introduced in rhtnf-alpha by reaction with n-succin ... | 1999 | 9862761 |
gamma delta t-cell function in pathogenesis of cerebral malaria in mice infected with plasmodium berghei anka. | mice depleted of gammadelta t cells by monoclonal antibody treatment and infected with plasmodium berghei anka did not develop cerebral malaria (cm). in striking contrast, delta0/0 mice infected with p. berghei developed cm despite their gammadelta t-cell deficiency. gammadelta t cells appear to be essential for the pathogenesis of cm in mice having experienced normal ontogeny but not in mice genetically deprived of gammadelta t cells from the beginning of life. | 1999 | 9864254 |
mosquito-plasmodium interactions in response to immune activation of the vector. | during the development of plasmodium sp. within the mosquito midgut, the parasite undergoes a series of developmental changes. the elongated ookinete migrates through the layers of the midgut where it forms the oocyst under the basal lamina. we demonstrate here that if aedes aegypti or anopheles gambiae, normally susceptible to plasmodium gallinaceum and p. berghei, respectively, are immune activated by the injection of bacteria into the hemocoel, and subsequently are fed on an infectious bloodm ... | 1999 | 9920043 |
plasmodium: immunization with carboxyl-terminal regions of msp-1 protects against homologous but not heterologous blood-stage parasite challenge. | a leading candidate for a vaccine targeted at the erythrocytic stages of plasmodial parasite development is the merozoite surface protein-1 (msp-1). we have previously shown that the carboxyl-terminal region of msp-1 derived from plasmodium yoelii yoelii 17xl, expressed as a fusion protein with glutathione s-transferase (gst-pyc2), can immunize mice against an otherwise lethal homologous challenge infection. this protection has been shown to be predominantly mediated by antibodies. we report her ... | 1999 | 9920045 |
plasmodium berghei: identification of an mdr-like gene associated with drug resistance. | amplification, mutations, or overexpression of the pfmdr1 gene have been associated with multiple drug resistance in some strains of plasmodium falciparum. in order to better understand this potential mechanism of drug resistance, we are currently investigating putative mdr homologues in vivo in the rodent malaria plasmodium berghei. we have identified and partially sequenced a gene that is amplified in a mfq-resistant (mfqr) line. using degenerate primers, a 579-bp fragment was amplified by pcr ... | 1999 | 9920046 |
plasmodium berghei and plasmodium yoelii: molecular karyotypes of drug-resistant lines. | 1999 | 9920047 | |
t cell recognition of hapten. anatomy of t cell receptor binding of a h-2kd-associated photoreactive peptide derivative. | to elucidate the structural basis of t cell recognition of hapten-modified antigenic peptides, we studied the interaction of the t1 t cell antigen receptor (tcr) with its ligand, the h-2kd-bound plasmodium berghei circumsporozoite peptide 252-260 (syipsaeki) containing photoreactive 4-azidobenzoic acid (aba) on p. berghei circumsporozoite lys259. the photoaffinity-labeled tcr residue(s) were mapped as tyr48 and/or tyr50 of complementary determining region 2beta (cdr2beta). other tcr-ligand conta ... | 1999 | 9920911 |
heterogeneous ribosome populations are present in plasmodium berghei during development in its vector. | the genome of the rodent malaria parasite, plasmodium berghei, contains two sets of variant ribosomal rna (rrna) genes, termed the a and s types, that are expressed predominantly during the vertebrate and mosquito stages of the parasite's development respectively. using in situ hybridization, we have examined the transcriptional activity of the a- and s-type rrna genes, and the switch in expression of the ribosome populations that occurs after parasite transmission to the mosquito. by detection ... | 1999 | 9987126 |
the development of murine cerebral malaria does not require nitric oxide production. | nitric oxide (no) production has been suggested to be required for the development of cerebral malaria. however, the importance of this molecule for the appearance of this pathology is debated. to assess whether murine cerebral malaria is no dependent, we investigated the course of blood-stage plasmodium berghei anka (pba) infections in inducible nitric oxide synthase (inos)-deficient mice. parasitaemia, haematological alterations, survival and development of cerebral malaria were not affected b ... | 1999 | 10028526 |
treatment with recombinant human tumour necrosis factor-alpha reduces parasitaemia and prevents plasmodium berghei k173-induced experimental cerebral malaria in mice. | the present study shows that treatment with recombinant human tumour necrosis factor-alpha (rhtnf-alpha) can suppress parasitaemia and prevents development of experimental cerebral malaria (ecm) in plasmodium berghei k173-infected mice. mice received rhtnf-alpha treatment either by subcutaneous injection of free or liposome-encapsulated rhtnf-alpha or sustained intraperitoneal administration of rhtnf-alpha given via mini-osmotic pumps. low-dose treatment with a subcutaneous bolus injection of rh ... | 1999 | 10070656 |
the biosynthesis and post-translational modification of pbs21 an ookinete-surface protein of plasmodium berghei. | radiolabelled methionine incorporation into synchronised plasmodium berghei gametocytes or ookinete cultures, showed that pbs21 is not synthesised in bloodstage parasites; synthesis was detected within three hours of induction of gametogenesis; synthesis was triggered at gametogenesis, not by fertilisation. we show native pbs21 to be a hydrophobic membrane protein that was insensitive to cleavage by phosphatidylinositol phospholipase c (pi-plc), but sensitive to alkaline hydroxylamine, and parti ... | 1999 | 10080386 |
role of glutathione in the detoxification of ferriprotoporphyrin ix in chloroquine resistant plasmodium berghei. | the reduction in hemozoin content is a well known feature of chloroquine-resistant plasmodium berghei. using nk65-derived lines displaying increasing resistance levels, we observed an inverse relationship between the hemozoin content, and the glutathione (gsh) and glutathione s-transferase (gst) levels. treatment of highly chloroquine-resistant-infected mice with buthionine sulfoximine (bso), which has previously been shown to partially reverse this chloroquine resistance, led to a significant i ... | 1999 | 10080390 |
subtle mutagenesis by ends-in recombination in malaria parasites. | the recent advent of gene-targeting techniques in malaria (plasmodium) parasites provides the means for introducing subtle mutations into their genome. here, we used the trap gene of plasmodium berghei as a target to test whether an ends-in strategy, i.e., targeting plasmids of the insertion type, may be suitable for subtle mutagenesis. we analyzed the recombinant loci generated by insertion of linear plasmids containing either base-pair substitutions, insertions, or deletions in their targeting ... | 1999 | 10082556 |
hepatic hematopoiesis in adult mouse during experimental rodent malaria. | during rodent malaria the development of the hematopoiesis in the liver was observed. this fact was used as a model for the study of the conditions and the features of the extramedullary hematopoietic differentiation, following the state of anaemia induced by parasitemia with plasmodium berghei. histological and ultrastructural data on the hepatic hematopoiesis are presented. | 1999 | 11845448 |
protective immunity against plasmodium berghei malaria after administration of interleukin-12. | interleukin-12 (il-12) has been shown to induce protection in mice against plasmodium cyanomolgi and in rhesus monkey against plasmodium yeolii. this study is to investigate whether recombinant il-12 can induce protection in balb/c mice against plasmodium berghei. five mice were given intraperitoneal injection of 7.5 micrograms/kg body weight recombinant mouse il-12 two days prior to challenge with 5 x 10(4) of p. berghei, while mice in the control group were injected with 0.5 ml of normal salin ... | 1999 | 11068418 |
the chemotherapy of rodent malaria. lvii. drug combinations to impede the selection of drug resistance, part 1: which model is appropriate? | the principle has finally been accepted that, whenever possible, antimalarial drugs should be deployed in appropriate combinations in endemic areas, in order to minimize the inevitability that monotherapy will, probably sooner than later, select populations of drug-resistant parasites. which laboratory models can predict the combinations of old or novel compounds that are likely to be of practical value in minimizing this risk? very few relevant data on the use of plasmodium falciparum in vitro ... | 1999 | 10707103 |
[genetic approach to the study of the sporogonic cycle in plasmodium]. | the development of transformation and mutagenesis techniques of the two species of plasmodium most studied--plasmodium falciparum (human parasite) and plasmodium berghei (rodent parasite)--opens new perspectives for the molecular study on the parasite sporogonic cycle in the insect vector. the parasite's stages that can be genetically transformed (the asexual erythrocytic stages) and gametocytes. the function of proteins coded by genes present in single copy in the genome can thus be studied aft ... | 1999 | 11000961 |
nitric oxide in murine malaria: divergent roles in blood and brain suggested by voltametric measures. | 1999 | 10717761 | |
[culture of plasmodium berghei with the short life span in mouse erythrocytes: evaluation of chloroquine resistance in three strains of the malaria parasite]. | this comparative study was made to examine chroloquine inhibition of c14-hypoxanthine incorporation (preferably nucleic acid precursor for plasmodium) in the short-living red blood cell cultures in mice infected with p. berghei strains differently sensitive to the agent 24 hours after incubation. these included 1) chloroquine-sensitive h strain; 2) lnk-65 strain having a spontaneously 2-3-fold decreased sensitivity to the agent; 3) strain lnk-65 chr selected for high resistance to chloroquine. i ... | 1999 | 11221002 |
suppressed expression of hypoxanthine-guanine phosphoribosyltransferase (hgprt) in an irradiation-attenuated plasmodium berghei xat strain. | plasmodium berghei xat (xat) is a non-reversible, non-lethal type malaria parasite strain derived from the highly virulent lethal p. berghei nk65 (nk65) by x-irradiation. the difference in polypeptide expression between nk65 and xat was examined in this study. western blot patterns of the parasite polypeptides showed that a 30-kda polypeptide was not detected in xat. in the present paper, we focused the study on the difference in the expression of the 30-kda polypeptide between xat and nk65. alt ... | 1999 | 11269277 |
[isolation and quantitation of chloroquine-binding proteins in plasmodium berghei]. | to isolate and quantitate chloroquine (cq)-binding proteins in both cq-sensitive (cs) and cq-resistant (cr) plasmodium berghei. | 1999 | 12563771 |
[differences in haemozoin production and pathogenicity between chloroquine-sensitive and chloroquine-resistant strains of plasmodium berghei]. | to better understand the differences in haemozoin formation and pathogenicity between chloroquine-sensitive(n) and chloroquine-resistant(rc) strains of plasmodium berghei. | 1999 | 12563809 |
[distribution of chloroquine in mitochondria, microsome and acid-precipitated protein from plasmodium berghei]. | 1999 | 12563846 | |
[synthesis of primaquine analogues and their antimalarial activity in mice]. | ten 4-methyl-5-substituted-phenoxy-6-methoxy-8-[(1-ethyl-4-amino) butylamino] quinolines (10a-j) have been synthesized and evaluated preliminarily for both suppressive and causal prophylactic antimalarial activities. the results of preliminary screening test showed that three of these compounds exhibited significant activity against plasmodium yoelii in mice, among which 10c was 4-8 times as effective as primaquine. moreover, 10c was superior to primaquine in suppressive test against plasmodium ... | 1998 | 11938965 |
[determination of polyamines in pyronaridine-sensitive and -resistant plasmodium berghei-infected erythrocytes]. | to understand the relationship between polyamine metabolism and pyronaridine resistance of malaria parasites. | 1998 | 12078217 |
[accumulation and effluxion of chloroquine in chloroquine-sensitive and chloroquine-resistant plasmodium berghei]. | to explore whether the difference in the amount of chloroquine (cq) accumulated in cq-resistant (cr) and in cq-sensitive (cs) p. berghei is involved in the infected erythrocytes (rbc) or in the parasites. | 1998 | 12078239 |
the effect of 2,2'-substitution on the metabolism and toxicity of dapsone in vitro and in vivo. | the effect of 2,2'-substitution with fluorine, methyl or trifluoromethyl groups on the toxicity, metabolism and pharmacological activity of dapsone has been investigated in vitro and in vivo. there was marked inter-species variation in the bioactivation (n-hydroxylation) of the compounds, as determined by methemoglobin formation. however, the inclusion of fluorine significantly (p<0.01) reduced methemoglobin formation compared with dapsone in all species studied. all three analogs resulted in si ... | 1998 | 21781861 |
developmental regulation of a plasmodium gene involves the generation of stage-specific 5' untranslated sequences. | the b7 gene of plasmodium berghei, highly conserved within the genus plasmodium, encodes a nuclear protein most likely involved in chromatin assembly. in this study we describe the transcription pattern of b7 during asexual multiplication and sexual differentiation of the parasites in the blood of the vertebrate host. two alternative transcripts have been identified: one, 1.4 kb in length is specific for asexual blood stages; the other, 1.8 kb in length is specific for sexually differentiated ce ... | 1998 | 9879886 |
stable expression of green fluorescent protein in blood and mosquito stages of plasmodium berghei. | 1998 | 9879905 | |
[utility of gamma rays in prophylaxis of transmissible malaria by blood transfusion]. | this study was carried out to evaluate the fortuitons advantage of using gamma irradiation in the prophylaxis of transmissible malaria by blood transfusion, with mice as the experimental model. in the first step, when the infected blood with plasmodium berghei was submitted to 2,500 rad and 5,000 rad, with or without metronidazol, there was no success, because the animals presented parasitaemia and died after inoculation of irradiated blood. however, there was partial success in the second step, ... | 1998 | 9859699 |
differential reactivity of brain microvascular endothelial cells to tnf reflects the genetic susceptibility to cerebral malaria. | upon infection with plasmodium berghei anka (pba), various inbred strains of mice exhibit different susceptibility to the development of cerebral malaria (cm). tumor necrosis factor-alpha (tnf) and interferon-gamma (ifn-gamma) have been shown to be crucial mediators in the pathogenesis of this neurovascular complication. brain microvascular endothelial cells (mvec) represent an important target of both cytokines. in the present study, we show that brain mvec purified from cm-susceptible (cm-s) c ... | 1998 | 9862335 |
protection from plasmodium berghei infection by priming and boosting t cells to a single class i-restricted epitope with recombinant carriers suitable for human use. | the desirability of inducing cytotoxic t cell responses to defined epitopes in humans has led to the development of a variety of recombinant delivery systems. recombinant protein particles derived from a yeast retrotransposon (ty) and the modified ankara vaccinia (mva) virus can deliver large epitope strings or even whole proteins. both have previously been administered safely in humans. immunization with recombinant ty and mva containing a single plasmodium berghei class i-binding epitope provi ... | 1998 | 9862371 |
peptide modification or blocking of cd8, resulting in weak tcr signaling, can activate ctl for fas- but not perforin-dependent cytotoxicity or cytokine production. | this study describes a form of partial agonism for a cd8+ ctl clone, s15, in which perforin-dependent killing and ifn-gamma production were lost but fas (apo1 or cd95)-dependent cytotoxicity preserved. cloned s15 ctl are h-2kd restricted and specific for a photoreactive derivative of the plasmodium berghei circumsporozoite peptide pbcs 252-260 (syipsaeki). the presence of a photoactivatable group in the epitope permitted assessment of tcr-ligand binding by tcr photoaffinity labeling. selective a ... | 1998 | 9862728 |
the complete sequence of plasmodium berghei merozoite surface protein-1 and its inter- and intra-species variability. | the complete gene for merozoite surface protein-1 (msp-1) from plasmodium berghei has been cloned and sequenced. comparison of the p. berghei msp-1 sequence with msp-1 from other rodent parasites reveals five conserved domains interrupted by four variable blocks. these variable blocks exhibit no sequence homology but do have similar amino acid compositions. primary proteolytic processing sites are located near the boundaries between the conserved domains and the variable blocks. sequencing of th ... | 1998 | 9662027 |
characterization of a subpopulation of mouse red blood cells as preferential target for malarial invasion. | cell electrophoresis was used to study a distinct subpopulation of murine red blood cells (rbc). these rbc are normally found in the spleen and bone marrow. they appear in the peripheral blood when mice are mildly bled or sucked by mosquitos. these cells have been characterized as having larger size, light density, lower electrophoretic mobility, and being more resistant to lysis with unsaturated fatty acids and in glycerol-containing medium than mature erythrocytes. all their features suggest t ... | 1998 | 9662186 |
malaria circumsporozoite protein inhibits protein synthesis in mammalian cells. | native plasmodium circumsporozoite (cs) protein, translocated by sporozoites into the cytosol of host cells, as well as recombinant cs constructs introduced into the cytoplasm by liposome fusion or transient transfection, all lead to inhibition of protein synthesis in mammalian cells. the following findings suggest that this inhibition of translation is caused by a binding of the cs protein to ribosomes. (i) the distribution of native cs protein translocated by sporozoites into the cytoplasm as ... | 1998 | 9669999 |
the efficiency of antigen recognition by cd8+ ctl clones is determined by the frequency of serial tcr engagement. | using h-2kd-restricted ctl clones, which are specific for a photoreactive derivative of the plasmodium berghei circumsporozoite peptide pbcs(252-260) (syipsaeki) and permit assessment of tcr-ligand interactions by tcr photoaffinity labeling, we have previously identified several peptide derivative variants for which tcr-ligand binding and the efficiency of ag recognition deviated by fivefold or more. here we report that the functional ctl response (cytotoxicity and ifn-gamma production) correlat ... | 1998 | 9670927 |
transgenic expression of a mosquito-stage malarial protein, pbs21, in blood stages of transformed plasmodium berghei and induction of an immune response upon infection. | pbs21 is a surface protein of the ookinete of plasmodium berghei, which can induce a potent transmission-blocking immune response. pbs21 is normally expressed only by parasite stages in the mosquito, i.e., female gametes/zygotes, ookinetes, and oocysts. however, the pbs21 gene is transcribed in female gametocytes which circulate in the bloodstream of the host, where translation of the resulting mrna is totally repressed. episomal transfection has been used to investigate whether expression of pb ... | 1998 | 9673276 |
isolation of merozoite rhoptries, identification of novel rhoptry-associated proteins from plasmodium yoelii, p. chabaudi, p. berghei, and conserved interspecies reactivity of organelles and proteins with p. falciparum rhoptry-specific antibodies. | rhoptries were isolated from merozoites of p. yoelii (17 xl), p. chabaudi adami and p. berghei (k-173), using sucrose gradient density centrifugation. mouse antisera was prepared against the organelles and characterized. antibodies specific for a known p. yoelii rhoptry protein were used to identify gradient fractions containing rhoptries and electron microscopy was used to confirm rhoptry enrichment and organelle morphology. western blotting analysis of the gradients with organelle-specific ant ... | 1998 | 9676705 |
rodent malaria in rats exacerbated by milk protein, attenuated by low-protein vegetable diet. | young male wistar rats were fed a purified, vegetable, low-protein diet containing 6% protein from maize gluten and 2% from soy protein isolate, or comparable diets in which maize gluten was replaced partly or completely by the equivalent amount of a milk protein concentrate. diets with adequate protein level (16% or 22%) served as a control. at 21 or 31 days of age, the rats were infected with 3000 or 100000 erythrocytes parasitized with plasmodium berghei. results reported include body weight, ... | 1998 | 9705196 |
an in vivo model to study the anti-malaric capacity of plant extracts. | an in vivo model to study the antimalaric effect of plant extracts is described. white mice (25-30 g body weight) are treated subcutaneously with 0.6 ml of the diluted extract starting seven days before p. berghei infection; treatment continues until death or for 30 days. simultaneously 0.2 ml of the extract are applied per os starting three days before infection. in a test of the model, treated and non-treated animals differed in body weight, survival time, haematocrite, parasitemia development ... | 1998 | 9711350 |
cloned lines of plasmodium berghei anka differ in their abilities to induce experimental cerebral malaria. | infection with plasmodium berghei anka is usually lethal. the parasite causes in some mouse strains a neurovascular syndrome, experimental cerebral malaria (ecm), involving immunopathological reactions. the effects on the development of ecm of the mouse genetic background have been clearly demonstrated, but nothing is known about the effects of the clonal diversity of the parasite. we showed that various cloned lines derived from a polyclonal line of p. berghei anka caused ecm but that the exten ... | 1998 | 9712753 |
upregulation of major histocompatibility complex (mhc) antigen in nephritis associated with murine malaria infection. | the importance of immune complexes in the pathogenesis of malarial nephritis is well established. the expression was studied of major histocompatibility complex (mhc) class i and class ii antigens and the infiltration of inflammatory cells, with their possible roles in cellular immune reactions in the pathogenesis of nephritis in a murine malaria model. thirty-six kidney sections obtained on days 5, 8-10, 15, and 20 from c57bl/6j mice acutely infected with plasmodium berghei and uninfected contr ... | 1998 | 9713350 |
in situ analysis of adhesion molecule expression in kidneys infected with murine malaria. | the expression of intercellular adhesion molecule-1 (icam-1), the ligand leucocyte function antigen-1 (lfa-1, cd11a), and complement receptor type 3 (cr3, or mac-1, cd11b) has been studied in murine kidneys acutely infected with the fatal malaria parasite plasmodium berghei anka. thirty-six kidney sections from five groups of c57bl/6j mice on day 5, 10, 15, and 20 post-infection, and normal controls, were stained with monoclonal antibodies against icam-1, lfa-1, and mac-1. there was markedly enh ... | 1998 | 9713351 |
picroliv prevents oxidation in serum lipoprotein lipids of mastomys coucha infected with plasmodium berghei. | picroliv, an iridoid glycoside mixture from the root and rhizome of picrorhiza kurrooa, at the dose of 6 mg/kg p.o. for two weeks provided significant protection against the generation of lipid peroxidation products in serum beta-lipoproteins of p. berghei infected m. coucha. incubation of normal rat hepatocytes with very low density lipoprotein or low density lipoprotein isolated from infected animals caused significant generation of lipid peroxides followed by a decrease in the viability of th ... | 1998 | 9717447 |
malaria parasites contain two identical copies of an elongation factor 1 alpha gene. | elongation factor 1alpha (ef-1alpha) is an abundant protein in eukaryotic cells, involved chiefly in translation of mrna on the ribosomes, and is frequently encoded by more than one gene. here we show the presence of two identical copies of the ef-1alpha gene in the genome of three malaria parasites, plasmodium knowlesi, p. berghei and p. falciparum. they are organized in a head-to-head orientation and both genes are expressed in a stage specific manner at a high level, indicating that the small ... | 1998 | 9719506 |
proteasome inhibitors block development of plasmodium spp. | proteasomes degrade most of the proteins inside eukaryotic cells, including transcription factors and regulators of cell cycle progression. here we show that nanomolar concentrations of lactacystin, a specific irreversible inhibitor of the 20s proteasome, inhibit development of the exoerythrocytic and erythrocytic stages of the malaria parasite. although lactacystin-treated plasmodium berghei sporozoites are still invasive, their development into exoerythrocytic forms (eef) is inhibited in vitro ... | 1998 | 9756786 |
synthesis and antimalarial activities of fluoroalkyl derivatives of dihydroartemisinin. | fluoroalkyl ethers (4) of dihydroartemisinin (2) have been prepared by reaction of fluoroalkyl alcohols with dihydroartemisinin by different methods (bf3,et2o or tmscl catalysis or mitsunobu reaction). ethers 4a-d derived from primary fluoroalkyl alcohols were obtained in moderate to good yields by these methods. ethers 4e-j have been prepared from fluoroalkyl secondary and tertiary alcohols and phenol using the mitsunobu reaction. although in vitro antimalarial activities of ethers toward plasm ... | 1998 | 9767645 |
bisquinolines. 2. antimalarial n,n-bis(7-chloroquinolin-4-yl)heteroalkanediamines. | n,n-bis(7-chloroquinolin-4-yl)heteroalkanediamines 1-11 were synthesized and screened against plasmodium falciparum in vitro and plasmodium berghei in vivo. these bisquinolines had ic50 values from 1 to 100 nm against p. falciparum in vitro. six of the 11 bisquinolines were significantly more potent against the chloroquine-resistant w2 clone compared to the chloroquine-sensitive d6 clone. for bisquinolines 1-11 there was no relationship between the length of the bisquinoline heteroalkane bridge ... | 1998 | 9784111 |
from noxiustoxin to shiva-3, a peptide toxic to the sporogonic development of plasmodium berghei. | this communication reviews shortly the main structural and functional characteristics of noxiustoxin, a 39 amino acid residue peptide, maintained closely packed by three-disulfide bridges and its effects on excitable membranes. shiva-3, a cecropin like-peptide composed of 38 amino acid residues is also briefly reviewed. its design and synthesis was made possible by the expertise gained through the work previously performed with noxiustoxin. one of the most prominent functional characteristics of ... | 1998 | 9792185 |
structural information on a cecropin-like synthetic peptide, shiva-3 toxic to the sporogonic development of plasmodium berghei. | this study is a contribution towards the understanding of the mode of action of shiva-3 and more generally that of cecropin-like peptides. structural information on shiva-3 (a cecropin-like synthetic peptide) in water and in a membrane-mimicking environment (trifluoroethanol alcohol, sds) were obtained using analytical centrifugation, cd and nmr spectroscopies. a total of 20 converged structures were retained on the basis of 197 non-redundant experimental constraints, including 166 distance cons ... | 1998 | 9799128 |
malaria infection of the mosquito anopheles gambiae activates immune-responsive genes during critical transition stages of the parasite life cycle. | six gene markers have been used to map the progress of the innate immune response of the mosquito vector, anopheles gambiae, upon infection by the malaria parasite, plasmodium berghei. in addition to four previously reported genes, the set of markers included nos (a nitric oxide synthase gene fragment) and ichit (a gene encoding two putative chitin-binding domains separated by a polythreonine-rich mucin region). in the midgut, a robust response occurs at 24 h post-infection, at a time when malar ... | 1998 | 9799221 |
characterisation of the cdc2-related kinase 2 gene from plasmodium knowlesi and p. berghei. | the complete sequence of the cdc2-related kinase 2 (crk2) gene from plasmodium knowlesi and from p. berghei was determined. in both species, the crk2 gene is closely linked to an elongation factor 1 alpha gene. the two crk2 proteins are highly homologous to the p. falciparum pfpk5 protein. the crk2 gene of both species is expressed at a low level during the asexual cell-cycle within the host erythrocytes. the p. berghei crk2 mrna is also present in gametocytes and in stages during development in ... | 1998 | 9803415 |
convulsions due to increased permeability of the blood-brain barrier in experimental cerebral malaria can be prevented by splenectomy or anti-t cell treatment. | experimental cerebral malaria (ecm) can be induced in c57b1 mice by infection with plasmodium berghei k173 parasites. behavioral changes shortly before they die of ecm may reflect disturbance of the integrity of the blood-brain barrier (bbb). folic acid elicits strong convulsive activity if the permeability of the bbb is increased. administration of folic acid to mice during development of ecm induced convulsions. interventions known to prevent fatal outcome from ecm, such as splenectomy or trea ... | 1998 | 9806067 |
plasmodium yoelii: identification of rhoptry proteins using monoclonal antibodies. | thirteen monoclonal antibodies, obtained after immunization of mice with plasmodium yoelii schizonts, were selected using immunofluorescence assay: they all presented typical fluorescence patterns of rhoptries. this antigen localization was confirmed by immunoelectron microscopy. the molecular weights of the recognized antigens are 68, 80, 105, 130 and 140 kda as determined by immunoprecipitation and immunoblot under reducing and nonreducing conditions. these values are very similar to these of ... | 1998 | 9806867 |
evidence for multiple pathologic and protective mechanisms of murine cerebral malaria. | murine cerebral malaria (cm) induced by plasmodium berghei anka kills susceptible mice within 24 to 48 h of onset of symptoms and is characterized by the production of inflammatory cytokines in the brain. c57bl/6j mice are sensitive to lethal cm, while a/j mice are resistant. these strains of mice were immunized with an adjuvant vaccine of killed whole-blood-stage parasites. the immunization protected c57bl/6 mice from lethal cm following virulent challenge. the same immunization increased the i ... | 1998 | 9826380 |
a novel antiprotozoal aminosteroid from saracha punctata. | a new aminosteroid, 3beta-amino-22,26-epiminocholest-5-ene named sarachine (1), and two known flavonoids, eriodictyol (2) and 7-o-beta-d-glucopyranosyl-eriodictyol (3), were isolated from the leaves of saracha punctata. the alkaloid was found to inhibit the growth of leishmania braziliensis promastigotes (100% at 25 microm) and of trypanosoma cruzi epimastigotes in culture (50% at 25 microm) and showed a strong in vitro antiplasmodial activity with an ic50 of 25 nm. | 1998 | 9834160 |
blocked hepatic-stage parasites and decreased susceptibility to plasmodium berghei infections in balb/c mice. | the balb/c strain of mice is comparatively more resistant to sporozoite infections of plasmodium berghei than the c57bl6 strain. infection with live sporozoites results in the formation of small hepatic forms in the balb/c liver that persist for as long as 6 days. upon infection with small numbers of sporozoites, some of the parasites are destroyed in the liver whereas the rest persist as blocked forms. when larger numbers of sporozoites are injected the same process occurs but, in addition, a f ... | 1998 | 9836306 |
involvement of macrophage scavenger receptors in protection against murine malaria. | macrophage scavenger receptor a (msr-a) deficient mice msr-a(-/-) were infected by the intraperitoneal injection of the plasmodium berghei nk65 strain in the erythrocytic stage. the msr-a(-/-) mice died significantly earlier than the control mice (p=0.060). in the surviving mice, two peaks of parasitemia were observed: the first 5-7 days and the second at 2-3 weeks after infection. death of all msr-a(-/-) mice occurred at either peak of parasitemia, suggesting that msr-a protects mice from sever ... | 1998 | 9840609 |
a family of chimeric erythrocyte binding proteins of malaria parasites. | proteins sequestered within organelles of the apical complex of malaria merozoites are involved in erythrocyte invasion, but few of these proteins and their interaction with the host erythrocyte have been characterized. in this report we describe maebl, a family of erythrocyte binding proteins identified in the rodent malaria parasites plasmodium yoelii yoelii and plasmodium berghei. maebl has a chimeric character, uniting domains from two distinct apical organelle protein families within one pr ... | 1998 | 9448314 |
plasmodium berghei anka: purification of large numbers of infectious gametocytes. | 1998 | 9501851 | |
the differing impact of chloroquine and pyrimethamine/sulfadoxine upon the infectivity of malaria species to the mosquito vector. | using serum or infected blood from danish volunteers and plasmodium falciparum-infected mozambican patients, respectively, the impact of curative doses of chloroquine and pyrimethamine/sulfadoxine upon infectivity of p. falciparum to anopheles arabiensis and an. gambiae or of p. berghei to an. stephensi was studied. both treatments cleared circulating p. falciparum gametocytes within 28 days. before this clearance, chloroquine enhanced infectivity to an. arabiensis, whereas pyrimethamine/sulfado ... | 1998 | 9502601 |
malaria transmission. has the ignition key been found? | 1998 | 9521315 | |
identification of xanthurenic acid as the putative inducer of malaria development in the mosquito. | malaria is transmitted from vertebrate host to mosquito vector by mature sexual blood-living stages called gametocytes. within seconds of ingestion into the mosquito bloodmeal, gametocytes undergo gametogenesis. induction requires the simultaneous exposure to at least two stimuli in vitro: a drop in bloodmeal temperature to 5 degrees c below that of the vertebrate host, and a rise in ph from 7.4 to 8.0-8.2. in vivo the mosquito bloodmeal has a ph of between 7.5 and 7.6. it is thought that in viv ... | 1998 | 9521324 |
orally active antimalarial 3-substituted trioxanes: new synthetic methodology and biological evaluation. | on the basis of a mechanistic understanding of the mode of action of artemisinin-like antimalarials, a series of structurally simple 3-aryl-1,2,4-trioxanes 5 was designed and was prepared in three to five operations from commercial reactants. the 3-aryl group was attached in each case as a nucleophile. in an electronically complementary fashion, 3-(fluoroalkyl)-trioxanes 6 were prepared via attachment of electrophilic fluoroalkyl esters. both in vitro and in vivo antimalarial evaluations of thes ... | 1998 | 9526568 |
plasmodium berghei: in vivo efficacy of albendazole in different rodent models. | 1998 | 9538870 | |
antimalarial activity of radicicol, heptelidic acid and other fungal metabolites. | in the course of our screening program for artemisinin-like antimalarial compounds from microorganisms, seven fungal metabolites such as radicicol and heptelidic acid were identified as active compounds. some of them exhibited antimalarial activity in vitro against the human malaria parasite plasmodium falciparum to the extent of approximately 1/10 as potent as artemisinin. radicicol was moderately active in vivo against plasmodium berghei in mice. | 1998 | 9544936 |
enhanced immunogenicity for cd8+ t cell induction and complete protective efficacy of malaria dna vaccination by boosting with modified vaccinia virus ankara. | immunization with irradiated sporozoites can protect against malaria infection and intensive efforts are aimed at reproducing this effect with subunit vaccines. a particular sequence of subunit immunization with pre-erythrocytic antigens of plasmodium berghei, consisting of single dose priming with plasmid dna followed by a single boost with a recombinant modified vaccinia virus ankara (mva) expressing the same antigen, induced unprecedented complete protection against p. berghei sporozoite chal ... | 1998 | 9546783 |
deletion of plasmodium berghei-specific cd4+ t cells adoptively transferred into recipient mice after challenge with homologous parasite. | the immune response to malaria parasites includes t cell responses that reduce parasites by effector t cell responses and by providing help for antibody responses. some parasites are more sensitive to antibody and others are more sensitive to cell-mediated immunity. we demonstrate that cultured cd4(+) t cells that produce interferon gamma and interleukin 2, but not interleukin 4, in response to stimulation with the rodent parasite plasmodium berghei can reduce but not eliminate parasites in vivo ... | 1998 | 9465082 |
dramatic changes in oxidative tryptophan metabolism along the kynurenine pathway in experimental cerebral and noncerebral malaria. | the pathogenesis of human cerebral malaria (cm) remains unresolved. in the most widely used murine model of cm, the presence of t lymphocytes and/or interferon (ifn)-gamma is a prerequisite. ifn-gamma is the key inducer of indoleamine 2,3-dioxygenase (ido), which is the catalyst of the first, and rate-limiting, step in the metabolism of tryptophan (trp) along the kynurenine (kyn) pathway. quinolinic acid (qa), a product of this pathway, is a neuro-excitotoxin, like glutamic acid (glu) and aspart ... | 1998 | 9466588 |
dysregulation of cytokine expression in tubulointerstitial nephritis associated with murine malaria. | we examined the circulating levels of the proinflammatory cytokines tumor necrosis factor-alpha (tnf-alpha), interleukin (il)-1 alpha, il-6, granulocyte macrophage-colony stimulating factor (gm-csf), and the anti-inflammatory cytokine il-10, and their expression in kidneys acutely infected with murine malaria parasite p. berghei anka in c57bl/6j mice. groups of six mice sacrificed on days 5, 10, 15, and 20, and normal controls were used for cytokine analysis. high concentrations of tnf-alpha and ... | 1998 | 9551390 |
reduced t helper 1 responses in il-12 p40 transgenic mice. | to investigate the antagonistic effect of il-12 p40 on il-12 activity in vivo, we generated transgenic (tg) mice in which p40 gene was regulated by a liver-specific promoter. three tg mouse lines were generated, and they expressed the p40 transgene predominantly in liver. serum p40 level was extremely high, and it consisted of mainly monomer and homodimer and also of higher m.w. complexes. these tg mice did not show any apparent phenotypic difference from control littermates in lymphoid cells. e ... | 1998 | 9551892 |
rational drug design approach for overcoming drug resistance: application to pyrimethamine resistance in malaria. | pyrimethamine acts by selectively inhibiting malarial dihydrofolate reductase-thymidylate synthase (dhfr-ts). resistance in the most important human parasite, plasmodium falciparum, initially results from an s108n mutation in the dhfr domain, with additional mutation (most commonly c59r or n51i or both) imparting much greater resistance. from a homology model of the 3-d structure of dhfr-ts, rational drug design techniques have been used to design and subsequently synthesize inhibitors able to o ... | 1998 | 9554869 |
the mosquito anopheles stephensi limits malaria parasite development with inducible synthesis of nitric oxide. | we have discovered that the mosquito anopheles stephensi, a natural vector of human malaria, limits parasite development with inducible synthesis of nitric oxide (no). elevated expression of a. stephensi no synthase (nos), which is highly homologous to characterized nos genes, was detected in the midgut and carcass soon after invasion of the midgut by plasmodium. early induction is likely primed by bacterial growth in the blood meal. later increases in a. stephensi nos expression and enzyme acti ... | 1998 | 9576947 |
glutathione peroxidase (ec 1.11.1.9) and superoxide dismutase (ec 1.15.1.1) activities in riboflavin-deficient rats infected with plasmodium berghei malaria. | riboflavin deficiency interferes with the growth and multiplication of malaria parasites as well as the host response to malaria. the objective of the present work was to determine the effects of riboflavin deficiency on erythrocyte glutathione peroxidase (ec 1.11.1.9; gpx) and superoxide dismutase (ec 1.15.1.1; sod) in rats infected with plasmodium berghei malaria. riboflavin in its co-enzyme form, fad, is required by glutathione reductase (ec 1.6.4.1) to regenerate gsh and gsh is an important ... | 1998 | 9577309 |
antimalarial and cytotoxic potential of four quassinoids from hannoa chlorantha and hannoa klaineana, and their structure-activity relationships. | hannoa chlorantha and hannoa klaineana (simaroubaceae) are used in traditional medicine of central african countries against fevers and malaria. four stem bark extracts from h. klaineana and four quassinoids from h. chlorantha were examined in vitro against plasmodium falciparum nf 54. the extracts displayed good activities, while the quassinoids were highly active, with ic50 values well below 1 microgram ml-1, those of chaparrinone and 15-desacetylundulatone being much lower than 0.1 microgram ... | 1998 | 9602388 |
high-level chloroquine resistance of plasmodium berghei is associated with multiple drug resistance and loss of reversal by calcium antagonists. | the chloroquine resistance of plasmodium falciparum is reversed in vitro by numerous compounds, including calcium antagonists, which could enhance the accumulation of the drug in the parasite food vacuole. however, this mechanism of resistance could be insufficient when the resistance level increases. using in vitro drug trials on strains of plasmodium berghei displaying various chloroquine-resistance levels, we confirmed previous results obtained in vivo in the chloroquine-resistant strains of ... | 1998 | 9602389 |
a pathogenic role of il-12 in blood-stage murine malaria lethal strain plasmodium berghei nk65 infection. | we studied whether the infection with a blood-stage murine malaria lethal plasmodium berghei nk65 induces il-12 production, and if so, how the il-12 production is involved in the protection or pathogenesis. the infection of c57bl/6 mice enhanced mrna expression of il-12 p40 and also ifn-gamma, il-4, and il-10 in both spleen and liver during the early course of the infection. it also enhanced the mrna expression of tnf-alpha, fas ligand, and cytokine-inducible nitric oxide synthase. increased il- ... | 1998 | 9605153 |
interleukin-12-dependent mechanisms in the clearance of blood-stage murine malaria parasite plasmodium berghei xat, an attenuated variant of p. berghei nk65. | the mechanism of development of host resistance to blood-stage malarial infection was studied by use of an irradiation-induced attenuated variant, plasmodium berghei xat, obtained from a lethal strain, p. berghei nk65. the infection enhanced mrna expression of interleukin (il)-12 p40 and also of interferon (ifn)-gamma, il-4, il-10, and cytokine-inducible nitric oxide synthase (inos) in spleen. treatment of these mice with anti-il-12 or anti-ifn-gamma led to the progression of parasitemia and fat ... | 1998 | 9607848 |
[ca++ ion transport blockers as reversants of the drug resistance of malarial parasites. 2. the effect of praziquantel on the resistance to chloroquine and compound r-70-zh of plasmodium berghei]. | the reversing action of anthelminthic praziquantel (p) on the effect of chloroquine (c) and compound r-70-zh (styrylquinazoline) was revealed on a plasmodium berghei model (white inbred mice), using a lnk65 isolate with naturally reduced sensitivity to chloroquine and its polyresistant line lnk65chlfr with acquired resistance to chloroquine/fansidar (selected in our laboratory). p (125 mg/kg) in combination with c showed a potentiating effect not only on the lnk65 isolate, but also on the lnk65c ... | 1998 | 9608206 |
precise timing of expression of a plasmodium falciparum-derived transgene in plasmodium berghei is a critical determinant of subsequent subcellular localization. | the development of transfection technology for malaria parasites holds significant promise for a more detailed characterization of molecules targeted by vaccines or drugs. one asexual blood stage vaccine candidate, apical membrane antigen-1 (ama-1) of merozoite rhoptries has been shown to be the target of inhibitory, protective antibodies in both in vitro and in vivo studies. we have investigated heterologous (trans-species) expression of the human malaria plasmodium falciparum ama-1 (pf83/ama-1 ... | 1998 | 9614123 |
mortality and platelet depletion occur independently of fibrinogen consumption in murine models of tumour necrosis factor-mediated systemic inflammatory responses. | tumour necrosis factor (tnf) is known to have procoagulant activity, and platelet depletion is a feature of tnf-mediated systemic inflammatory responses. the aim of this study was to investigate the role of fibrinogen consumption in the development of tnf-mediated systemic inflammatory responses and in the associated depletion of platelets. three murine models of tnf-mediated systemic inflammatory responses were examined: the systemic toxicity reactions (str) induced by tnf or lipopolysaccharide ... | 1998 | 9619377 |
transgenic mice with elevated level of cuznsod are highly susceptible to malaria infection. | copper/zinc superoxide dismutase (cuznsod) catalyses the conversion of o2.- into h2o2. constitutive overexpression of cuznsod in cells and animals creates an indigenous oxidative stress that predisposes them to added insults. in this study, we used transgenic cuznsod (tg-cuznsod) mice with elevated levels of cuznsod to determine whether overexpression of cuznsod affected the susceptibility of these mice to plasmodium infection. acute malaria is associated with oxidative stress, mediated by redox ... | 1998 | 9641269 |
novel aryl-bis-quinolines with antimalarial activity in-vivo. | three rationally designed isomeric aryl-bridged bis-quinolines, n1,nx-bis(7-chloroquinolin-4-yl)phenylene-1,x-diamines, where x=2, 3 or 4, i.e. o-, m- and p-substituted analogues respectively, were synthesized and evaluated against plasmodium berghei in-vivo. the compound with x=2 had an id50 of 30 mg kg(-1), whereas the p-substituted analogue (x=4) was not statistically schizonticidal at either of the two dose levels tested in olive oil-dimethylsulphoxide (5 and 25 mg kg(-1), id50=60 mg kg(-1) ... | 1998 | 9643441 |
novel quinone methides from salacia kraussii with in vitro antimalarial activity. | three novel quinone methides, i.e., 28-nor-isoiguesterin-17-carbaldehyde (1), 17-(methoxycarbonyl)-28-nor-isoiguesterin (2), and 28-hydroxyisoiguesterin (3), together with the known celastrol (5), pristimerin (6), and isoiguesterol (7), were isolated from the roots of salacia kraussii (celastraceae) by bioassay-guided fractionation. the structures of the compounds were determined by dept and 2d nmr techniques. the isolates showed antimalarial activity 30-50-fold greater than their cytotoxicity ( ... | 1998 | 9644053 |
liver ultrastructural pathology in mice infected with plasmodium berghei. | as liver can be an important target organ in malaria, we performed an ultrastructural study of hepatic alterations in the final stage of plasmodium berghei infection in mice. significant hepatocyte abnormalities were found. an elevated number of cells showed mitochondria with a high electron-dense matrix and multiple changes in shape and size, alterations in the structure of golgi complex, swelling and disorganisation of both rough and smooth-surfaced endoplasmic reticulum, differently shaped pe ... | 1998 | 9648294 |
transforming growth factor beta production is inversely correlated with severity of murine malaria infection. | we have examined the role of the immunomodulatory cytokine transforming growth factor (tgf)-beta in the resolution and pathology of malaria in balb/c mice. circulating levels of tgf-beta, and production of bioactive tgf-beta by splenocytes, were found to be low in lethal infections with plasmodium berghei. in contrast, resolving infections with p. chabaudi chabaudi or p. yoelii were accompanied by significant tgf-beta production. a causal association between the failure to produce tgf-beta and t ... | 1998 | 9653082 |