Publications
| Title | Abstract | Year(sorted ascending) Filter | PMID Filter |
|---|
| the plasma membrane and mitochondrial membrane potentials of plasmodium yoelii. | 1. the plasma membrane potential and the mitochondrial membrane potential of p. yoellii was examined by fluorescence microscopy using rhodamine 123 and by transmembrane distribution of tetraphenylphosphonium. 2. the mitochondrion of p. yoelii, free of gametocyte stage, maintained a high negative inside membrane potential. 3. deprivation of glucose in incubation medium largely abolished the plasma membrane potential but not the mitochondrial membrane potential. 4. studies with metabolic inhibitor ... | 1988 | 3224510 |
| effect of temperature on erythrocyte-free plasmodium yoelii. | 1988 | 3252761 | |
| [some ultrastructural characteristics of plasmodium yoelii yoelii in erythrocytic schizogony and gametocytosis]. | 1988 | 3253022 | |
| single dose curative and prophylactic efficacy of antimalarial drugs against multi-resistant plasmodium yoelii nigeriensis. | 1988 | 3256563 | |
| selection of plasmodium yoelii nigeriensis resistant to triple drug combination (sulphadoxine/pyrimethamine/mefloquine) and its response to other antimalarials. | 1988 | 3266603 | |
| variation among circumsporozoite protein genes from rodent malarias. | we investigated the effect of long term passage of parasites in naive animals on the circumsporozoite protein (csp) gene of plasmodium yoelii. the csp gene sequence was determined from a non-lethal cloned line of p. yoelii and compared to the csp gene sequence from a lethal strain of p. yoelii. the two parasite lines were originally derived from the same isolate, but were separated 17 years ago followed by continued passage. the sequence of the csp gene and its surroundings from the non-lethal l ... | 1988 | 3287156 |
| malarial parasites induce tnf production by macrophages. | mouse peritoneal macrophages incubated with erythrocytes infected with non-lethal or lethal variants of plasmodium yoelii or with p. berghei, in the presence of polymyxin b to exclude the effects of any contaminating endotoxin, secreted a cytotoxic factor into the supernatant that was shown to be tumour necrosis factor (tnf). no differences were observed in the ability of the three types of parasite to induce tnf production, which was maximal in the range of 0.2-5 infected erythrocytes per macro ... | 1988 | 3292408 |
| leishmania mexicana: effect of concomitant malaria on cutaneous leishmaniasis. development of lesions in a leishmania-susceptible (balb/c) strain of mouse. | effect of concomitant malaria on cutaneous leishmaniasis. development of lesions in a leishmania-susceptible (balb/c) strain of mouse. experimental parasitology 65, 269-276. symptoms of human leishmaniasis vary greatly, ranging from cryptic infections to cases with fatal sequelae. factors regulating the severity of the disease are largely undetermined. malaria coincides geographically with leishmaniasis in many areas and the immunosuppressive effects of malaria are well documented. it is therefo ... | 1988 | 3350106 |
| inbred mice infected with plasmodium yoelii differ in their antimalarial immunoglobulin isotype response. | antibodies are known to be important in mediating malarial immunity, but the influence of the various immunoglobulin isotypes on parasite elimination is unclear. the purpose of this study was to provide basic information on the induction of isotype expression in genetically different mice during primary malaria. parasitaemias and the serum antimalarial igm, igg1, igg2, igg3 and iga antibody titres measured in a radioimmunoassay were followed in outbred and 11 inbred strains of mice infected with ... | 1988 | 3353128 |
| immunoregulation in murine malaria. susceptibility of inbred mice to infection with plasmodium yoelii depends on the dynamic interplay of host and parasite genes. | inbred and h-2 congenic mouse strains were tested for their ability to resist infections with the non-lethal 17x or with the lethal ym isolates of plasmodium yoelii. dba/2 and b10.d2 mice, which best resisted infections with non-lethal p. yoelii, were exquisitely susceptible to infection with lethal isolates of this malaria species. in contrast, b6 and b10 mice, which were susceptible to infection with non-lethal p. yoelii, were resistant to infection with the lethal isolates. this reversal of h ... | 1988 | 3379305 |
| an immunogenic antigen of murine plasmodium yoelii 17x associates with class i mhc glycoproteins. | reticulocytes infected with the non-lethal variant of plasmodium yoelii 17x (py17x-nl) express elevated levels of class i, but not class ii, mhc ag when compared with non-parasitized reticulocytes. in contrast, class i ag are not detectable on erythrocytes parasitized by the lethal variant py17x-l. in addition, the responder status of various inbred strains of mice to py17x-nl has been shown to positively correlate with the levels of class i mhc antigens expressed on py17x-nl parasitized red blo ... | 1988 | 3379306 |
| igh-c allotype-linked control of anti-dna production and clonotype expression in mice infected with plasmodium yoelii. | the infection of nonlethal strain of plasmodium yoelii induces the formation of igg anti-dna antibodies as a result of polyclonal b cell activation. by using various nonautoimmune strains of mice including h-2 or igh congenic or recombinant mice, the levels and clonotypes of anti-dna antibodies elicited by the malaria infection were analyzed in relation to the expression of the mhc or igh gene. our results showed there were little, if any, differences in serum anti-dna levels and their clonotype ... | 1988 | 3139752 |
| heterologous synergistic interactions in concurrent experimental infection in the mouse with schistosoma mansoni, echinostoma revolutum, plasmodium yoelii, babesia microti, and trypanosoma brucei. | primary infections with plasmodium yoelii and echinostoma revolutum in the mouse induced a significant increase in the heterologous schistosoma mansoni challenge worm establishment, whereas s. mansoni worm establishment remained unaffected by primary infections with trypanosoma brucei and babesia microti. concurrent infection in the mouse with p. yoelii or t. brucei, but not with b. microti, blocked the resistance to homologous e. revolutum challenge infection, and primary p. yoelii and t. bruce ... | 1988 | 3143108 |
| a protective monoclonal antibody recognizes a variant-specific epitope in the precursor of the major merozoite surface antigen of the rodent malarial parasite plasmodium yoelii. | the precursor of the major merozoite surface ag (pmmsa) represents one of the principal molecules of the erythrocytic stages of malarial parasites. previously we reported that mab 302 recognizing the 230-kda pmmsa of plasmodium yoelii provided passive protection to mice challenged with this parasite. we now report that the protective capacity of mab 302 is variant specific, affording protection against infection with only three of five p. yoelii lines. immunoprecipitation analyses of their pmmsa ... | 1989 | 2467942 |
| cloning of plasmodium yoelii genes expressing three different sporozoite-specific antigens. | genomic dna isolated from plasmodium yoelii (strain #17xnl) was prepared by partial digestion and cloned in escherichia coli tb-1 with puc18 plasmid. antigen-producing recombinants were detected by a battery of monoclonal antibodies against antigens of the sporozoite stages. four clones producing stage-specific sporozoite antigens were identified. one produced p. yoelii circumsporozoite protein, and three produced other p. yoelii sporozoite antigens. | 1989 | 2472543 |
| mechanisms of splenic control of murine malaria: cellular reactions of the spleen in lethal (strain 17xl) plasmodium yoelii malaria in balb/c mice, and the consequences of pre-infective splenectomy. | the splenic response in lethal 17xl plasmodium yoelii murine malaria is vigorous, displaying marked phagocytosis, erythropoiesis, lymphopoiesis, plasmacytopoiesis, and, from day 3 of infection, increasing levels of parasitized erythrocytes. there is also a pronounced response of newly characterized fibroblastic stromal cells which branch and fuse with one another, forming extensive, complex, irregular, syncytial membranous sheets which provide a variety of barriers. hence, i term these barrier c ... | 1989 | 2476037 |
| a protective monoclonal antibody recognizes an epitope in the carboxyl-terminal cysteine-rich domain in the precursor of the major merozoite surface antigen of the rodent malarial parasite, plasmodium yoelii. | the 195-kda major merozoite surface antigen of plasmodium falciparum (pf pmmsa) is a potential candidate for the development of a blood-stage malarial vaccine. we have focused on an analogous 230-kda ag of the rodent malarial parasite, plasmodium yoelii, in an effort to study this protein in an experimental model system. previously we reported the cloning and sequencing of a 2.1-kb portion of the gene encoding the carboxyl-terminal 77 kda of the py pmmsa. this region contained the b cell epitope ... | 1989 | 2477452 |
| nile blue as a stain for exoerythrocytic forms of plasmodium yoelii. | 1989 | 2481349 | |
| role of ifn-gamma in lethal and nonlethal malaria in susceptible and resistant murine hosts. | ifn-gamma plays an important role in host defense against microbial disease. here, we studied the role of ifn-gamma in lethal and nonlethal murine malaria. administration of recombinant murine ifn-gamma resulted in a dose-dependent protection of sw, balb/cbyj, and cba/j mice from the lethal variant of plasmodium yoelii 17x (pyl) but had little effect on the course of the nonlethal variant of this parasite (pynl). administration of recombinant ifn-gamma also resulted in the activation of peritone ... | 1989 | 2506274 |
| genetic control of immunity to plasmodium yoelii sporozoites. | using a rodent malaria system, we have shown that protective immunity to the preerythrocytic stages of malaria is genetically controlled by mhc and non-mhc genes. ten congenic strains of mice were immunized with irradiated sporozoites of plasmodium yoelii. when challenged with viable sporozoites, only two strains had a high proportion of animals that did not develop blood stage infections. immunity did not correlate with antisporozoite antibody levels. two protective mechanisms exist determined ... | 1989 | 2512354 |
| experimental infections of plasmodium yoelii nigeriensis in mice and rats, and hosts' reactions. | in investigations into the course of infection of plasmodium yoelii nigeriensis in rats and mice, it was found that adult mice, baby mice and baby rats were susceptible to the infection, while adult rats were totally refractive. the infection was rapidly fatal in baby and adult mice but was maintained with a low parasitaemia and tolerated by baby rats until the animals were 7 weeks old, after which they eradicated the infection totally. although the adult rats did not exhibit any parasitaemia, t ... | 1989 | 2545080 |
| sequences similar to genes for two mitochondrial proteins and portions of ribosomal rna in tandemly arrayed 6-kilobase-pair dna of a malarial parasite. | erythrocytic stages of mammalian malarial parasites contain acristate mitochondria whose functions are not well understood. moreover, little is known about the genome of these organelles. we have previously reported that all species of malarial parasites examined contain highly conserved, tandemly arrayed dna with a unit length of about 6.0 kb that is transcribed into discrete rna molecules in erythrocytic stages. we now report the complete dna sequence of the 5984-bp repeating unit of plasmodiu ... | 1989 | 2549417 |
| the effect of pentostam and cimetidine on the development of leishmaniasis (leishmania mexicana amazonensis) and concomitant malaria (plasmodium yoelii). | balb/c mice were infected with leishmania mexicana amazonensis and/or plasmodium yoelii in order to determine the impact of multiple parasitic infection on the efficacy of chemotherapeutic agents. uninfected, p. yoelii-infected, l.m. amazonensis-infected, and l.m. amazonensis and p. yoelii-infected mice were inoculated with cimetidine (80 mg kg-1 day-1) or pentostam (200 mg kg-1 day-1) once a day for an initial 20-day period, and once a week thereafter. leishmania mexicana amazonensis lesion dev ... | 1989 | 2557804 |
| rapid clearance of plasmodium yoelii-infected erythrocytes after exposure to the ionophore a23187. | 1. the effects of ca2+ and the calcium ionophore a23187 on the intraerythrocytic development of the asexual forms of plasmodium yoelii were examined. 2. erythrocyte-free parasites obtained by saponin lysis of infected cells remained viable after exposure to 1 mm ca2+. 3. a23187 inhibited the growth of p. yoelii and the inhibition was augmented by ca2+ in cells infected with parasites at young stage of development. 4. a23187-treated infected cells disappeared from the circulation shortly after in ... | 1989 | 2567656 |
| [ultrastructural study on effect of primaquine on sporogonic stage of plasmodium yoelii nigeriensis]. | ultrastructural changes of oocysts and sporozoites of plasmodium yoelii nigeriensis was observed. anopheles stephensi were allowed to obtain blood meal from the mice which had been administered with primaquine diphosphate at different doses and times. mosquitoes were directed and prepared 6-13 d following infection. electron microscopy showed that the development and morphology of a number of oocysts and sporozoites in infected mosquitoes after treatment became abnormal. the cytoplasma of the oo ... | 1989 | 2610001 |
| effect of irradiation on plasmodium sporozoites depends on the species of hepatocyte infected. | the use of models such as rodents immunized with irradiated rodent malaria sporozoites can be helpful in defining the hepatic antigens which elicit a protective response. after "normal" penetration into the hepatocyte, and "normal" transformation, into trophozoites, irradiated sporozoites are known to begin development, but abort after a period of time that depends on the dose of radiation received. experiments performed with cultured rat, mouse and thamnomys gazellae hepatocytes infected with p ... | 1989 | 2623430 |
| in vitro and in vivo activities of atalaphillinine and related acridone alkaloids against rodent malaria. | thirty acridone alkaloids obtained from citrus, glycosmis, or severinia plants (members of the family rutaceae) were tested for their antimalarial activities in vitro and in vivo. at a concentration of 10 micrograms/ml in vitro, seven of these alkaloids suppressed 90% or more of plasmodium yoelii, which causes malaria in rodents. atalaphillinine, when injected intraperitoneally in a daily dose of 50 mg/kg for 3 days into mice infected with 10(7) erythrocytes parasitized with plasmodium berghei o ... | 1989 | 2653215 |
| soluble malarial antigens are toxic and induce the production of tumour necrosis factor in vivo. | heat-stable soluble products of rodent malarial parasites induce activated peritoneal macrophages to secrete tumour necrosis factor (tnf) in vitro. since heat-stable parasite antigens are known to be present in the circulation of patients with malaria and it has been suggested that much of the pathology of malaria is due to tnf, we investigated the ability of such antigens to induce the production of tnf in vivo and to be toxic to mice. injection of antigens obtained from plasmodium yoelii or fr ... | 1989 | 2654012 |
| immunotoxicity of the semiconductor gallium arsenide in female b6c3f1 mice. | the effects of gallium arsenide (gaas) exposure on immunocompetence of b6c3f1 female mice were investigated. gaas was administered as a single intratracheal instillation at doses of 50, 100, and 200 mg/kg. fourteen days after exposure, various cellular and humoral immune parameters were assessed. gaas exposure increased spleen cellularity in a dose-dependent manner. however, the percentages of thy 1.2 positive and ig positive cells were decreased and that of f4/80 positive cells was increased do ... | 1989 | 2695379 |
| effects of pyran copolymer on host resistance of mice to plasmodium yoelii. | female b6c3f1 mice treated with 25 mg/kg pyran intravenously (i.v.) on days -4 and -3 were more susceptible to nonlethal plasmodium yoelii 17xnl or lethal plasmodium berghei atcc-30090 than untreated mice or mice treated intraperitoneally (i.p.). female b6c3f1 mice treated with pyran i.p. displayed enhanced resistance to listeria monocytogenes as compared to untreated mice or mice given pyran i.v. peritoneal exudate cells (pec) primed by pyran i.p. possessed enhanced ability to kill listeria but ... | 1989 | 2723926 |
| igg3 is the major source of cryoglobulins in mice. | a total of 20 of 23 igg3 mab derived from unmanipulated autoimmune mrl/mpj-lpr/lpr mice was shown to generate cryoglobulins which were composed exclusively of igg3. although three igg3 mab failed to develop cryoglobulins, they were able to bind nonspecifically to any igg3 molecules as efficiently as cryoprecipitable igg did. the direct role of the gamma 3 constant region for the generation of cryoglobulins was demonstrated by the following findings: 1) the cryoglobulin activity was independent o ... | 1989 | 2738401 |
| dual action of anti-sporozoite antibodies in vitro. | with the use of a double staining technique that permits localization of the sporozoite during the process of entering a host cell, we studied the biologic effects of three mab directed against determinants contained in the circumsporozoite of plasmodium yoelii. these mab, which included one igm and two igg3, were studied in primary cultures of rodent hepatocytes inoculated with sporozoites of p. yoelii. these results confirm previous reports of the extended action of antibodies on plasmodium fa ... | 1989 | 2745980 |
| induction of nucleoside transport sites into the host cell membrane of babesia bovis infected erythrocytes. | normal bovine erythrocytes have negligible ability to transport adenosine and related nucleosides across their cell membrane. however, infection with the intraerythrocytic parasite babesia bovis was found to induce a nucleoside permeation site into the host cell membrane. transport experiments over periods of up to 30 s determined that the transport rate of 1 microm adenosine into the infected cell was 1.72 +/- 1.2 pmol incorporated (microliter cell water)-1s-1, a rate three times higher than fo ... | 1989 | 2747745 |
| qinghaosu, dietary vitamin e, selenium, and cod-liver oil: effect on the susceptibility of mice to the malarial parasite plasmodium yoelii. | young female mice were fed torula-yeast-based diets deficient in vitamin e or selenium or supplemented with cod-liver oil to determine the effect of host antioxidant status on the therapeutic efficacy of the chinese traditional antimalarial drug qinghaosu (qhs), a sesquiterpene endoperoxide. vitamin e deficiency enhanced the antimalarial action of qhs against plasmodium yoelii, both in terms of decreased parasitemia and improved survival but se deficiency did not. a vitamin e-deficient diet cont ... | 1989 | 2756922 |
| [scanning electron microscopic observations of ookinete formation of plasmodium yoelii yoelii in vitro]. | the ookinete formation and mature ookinete of plasmodium yoelii yoelii were described. during the development from zygote to ookinete, at first a finger-shaped or a stick-shaped projection protruded from one side of zygote. the anterior end of the projection assumed a truncated cone shape. following enlargement of the projection, the body of zygote gradually wrinkled and shrank and became smaller. an annular structure developed between the newly formed ookinete and the remaining body of zygote, ... | 1989 | 2766499 |
| transport processes of 2-deoxy-d-glucose in erythrocytes infected with plasmodium yoelii, a rodent malaria parasite. | the transport processes of d-glucose in plasmodium yoelii-infected mouse erythrocytes were investigated using 2-deoxy-d-glucose (2dog), a non-metabolizable analogue of d-glucose. infected cells showed an increase in the uptake of 2dog compared to uninfected controls, and an effect which was more prominent in cells with mature-stage parasites. kinetic studies measuring the initial rates of 2dog uptake revealed two components in infected cells with late trophozoite and schizont-stage parasites: a ... | 1989 | 2771446 |
| antimalarial efficacy of arteether against multiple drug resistant strain of plasmodium yoelii nigeriensis. | new quick-acting blood schizontocides are needed to contain the spread of multiple drug resistant strains of p. falciparum and for the treatment of the cerebral malaria cases. a multiple drug resistant strain of p. yoelii nigeriensis resistant to mefloquine (128 mg/kg x 6 days), quinine (300 mg/kg x 7 days) and chloroquine (64 mg/kg x 8 days) was found to be completely susceptible to arteether (a 30:70 mixture of alpha and beta enantiomers) and a dose of 5 mg/kg x 3 days by i.m. route was curati ... | 1989 | 2771860 |
| mechanisms of splenic control of murine malaria: tissue culture studies of the erythropoietic interplay of spleen, bone marrow, and blood in lethal (strain 17xl) plasmodium yoelii malaria in balb/c mice. | this work characterizes the erythropoietic interplay of the spleen, blood, and bone marrow in a lethal murine malaria, strain 17xl p. yoelii. this malaria runs a fulminant 7 day course in balb/c/byj mice, marked by high levels of parasitized reticulocytes with death likely due to anemia. we have quantitated the levels of burst forming units-erythroid (bfu-e), the early, niche-seeking, largely erythropoietin-unresponsive erythropoietic precursors, and of colony forming units-erythroid (cfu-e), th ... | 1989 | 2774062 |
| cloning and analysis of the gene encoding the 230-kilodalton merozoite surface antigen of plasmodium yoelii. | the complete nucleotide sequence of the gene for the 230-kda precursor to the major merozoite surface antigens (pmmsa) of plasmodium yoelii ym has been determined. a single open reading frame of 5316 bp encodes a protein of calculated molecular mass 197,000. the deduced amino acid sequence contains potential signal peptide and membrane anchor sequences of 19 and 18 residues, respectively, and a region of six tandemly repeated tetrapeptides, gly-ala-val-pro. comparison with the 195-kda plasmodium ... | 1989 | 2797063 |
| precursor to the major merozoite surface antigen of plasmodium yoelii: cloning and sequencing of the middle 1.9-kb region. | 1989 | 2797064 | |
| studies on the mechanism of anemia in rodent malaria. | the underlying cause of anemia is one of the problems to be solved in malaria research. many factors are involved in reducing the quantity of uninfected red blood cells (rbc) in addition to those infected rbc destroyed by malaria parasites. in the plasmodium yoelii (p.y.)-mouse model, the amount of [51cr]-labelled normal mouse rbc destroyed in peripheral blood as well as the quantity phagocytized by spleen cells during acute and chronic infection in vivo is reported in this paper. our results sh ... | 1989 | 2798398 |
| adoptive transfer of cd8+ t cells from immune animals does not transfer immunity to blood stage plasmodium yoelii malaria. | the malaria parasite, plasmodium yoelii 17x, causes a self-limited, nonlethal infection characterized, in the blood stage, by preferential invasion of reticulocytes. previous studies have suggested that immunity to the blood stage infection may be related to enhanced levels of class i mhc ag on the parasitized reticulocyte surface and can be adoptively transferred to immunodeficient mice by immune cd8+ t cells in the absence of cd4+ t cells. to further examine the mechanisms of cd8+ t cell invol ... | 1990 | 1967271 |
| cd4+ t cells play a major role for igm and igg anti-dna production in mice infected with plasmodium yoelii. | the infection by a non-lethal strain of plasmodium yoelii induces the formation of autoantibodies such as anti-dna and anti-sm antibodies in mice. the extent of the relative increase in serum levels of igm and igg anti-dna and anti-sm antibodies and their kinetics were found to be similar to those of anti-hapten antibodies and of total igm and igg levels. this strongly suggested that anti-dna and anti-sm autoantibody responses observed in malaria-infected mice are a result of polyclonal activati ... | 1990 | 1968798 |
| cellular mechanisms in immunity to blood stage infection. | we studied mechanisms of immunity to blood stage infection in the mouse malarias plasmodium vinckei and plasmodium yoelii 17x. infection with p. vinckei was uniformly lethal, whereas p. yoelii 17x caused a self-limited, nonlethal infection. transfer of immune cd4+ t cells conferred protection against p. yoelii in nude mice. previous studies by others had suggested that immunity to p. yoelii may be related to mhc class i expression on reticulocytes and found that cd8+ t cells alone transferred pr ... | 1990 | 1980907 |
| hepatic phase of malaria is the target of cellular mechanisms induced by the previous and the subsequent stages. a crucial role for liver nonparenchymal cells. | both the sporozoites and the erythrocytic stages can modulate the hepatic phase by cytokines, notably ifn-gamma, tnf and il-6, either directly or as a result of a cascade of events, and by mhc-restricted and antibody-dependent cell-mediated cytotoxicity. the role played by cd8+ t cells in inducing protective immunity against pre-erythrocytic stages is clearly established. the potential interest of triggering peptide-primed cd4+ t cells has to be considered regarding protection. indeed, cd4+ t ce ... | 1990 | 1980910 |
| activities of new acridone alkaloid derivatives against plasmodium yoelii in vitro. | forty-seven new acridone alkaloid derivatives (sa compounds) were tested for antimalarial activity in vitro. at a concentration of 1.0 microgram/ml, six of these inhibited 50% or more of the incorporation of [3h]hypoxanthine into plasmodium yoelii in vitro. the four most potent compounds, sa 3757, sa 3548, sa 3761 and sa 3499, showed 50% inhibitory concentration (ic50) values of 0.023 microgram/ml, 0.03 microgram/ml, 0.053 microgram/ml and 0.15 microgram/ml, respectively. the chemotherapeutic in ... | 1990 | 2080937 |
| reduced antibody response to the repetitive sequence of the plasmodium falciparum circumsporozoite protein in mice infected with plasmodium yoelii blood forms. | the immunogenicity of the carrier-free synthetic peptide, (nanp)40, from the repetitive region of the plasmodium falciparum circumsporozoite (cs) protein was investigated in genetically responder mice (c57bl/6, h-2b) acutely infected with blood forms of the non-lethal murine malaria parasite, p. yoelii. as compared to non-infected mice, p. yoelii-infected c57bl/6 mice produced significantly lower titers of anti-(nanp)40 igg antibodies. this decrease in the anti-(nanp)40 antibody response peaked ... | 1990 | 2082157 |
| generation of a cytotoxic t-lymphocyte response using a salmonella antigen-delivery system. | we have constructed a general-use vector for the cloning and stable expression of foreign genes in the chromosome of attenuated salmonella typhimurium. using this chromosomal expression vector (cev), we expressed the circumsporozoite (cs) gene of the mouse malaria plasmodium yoelii in an aroa s. typhimurium strain. mice immunized with cs-expressing salmonella recombinants mount a cs-specific cytotoxic t-lymphocyte (ctl) response. this is the first demonstration that attenuated salmonella can eli ... | 1990 | 2089224 |
| molecular cloning and sequence analysis of the gene encoding the major merozoite surface antigen of plasmodium chabaudi chabaudi ip-pc1. | the complete nucleotide sequence of the gene encoding the precursor to the major merozoite surface antigens of plasmodium chabaudi chabaudi strain ip-pc1 has been determined. a single open reading frame was detected, that coded for a protein of 199 kda. the encoded protein (p199) contains putative signal and membrane anchor sequences and shows a clustering of cys residues in the last 120 amino acids. incompletely conserved tandem repeat oligopeptides are present at different positions in the mol ... | 1990 | 2090945 |
| genetic restriction of protective immunity to plasmodium yoelii sporozoites. | ten congenic strains of mice were immunized with irradiated sporozoites of plasmodium yoelii. when challenged with viable sporozoites, only two strains had a high proportion of animals which did not develop blood-stage infections. genes both within and outside the h-2 region affected the degree of protection. immunity did not correlate with anti-sporozoite antibody levels. in vivo depletion of cd8+ t cells did not alter immunity in two of three congenic strains, implying the existence of a novel ... | 1990 | 2094575 |
| evaluation of vaccines designed to induce protective cellular immunity against the plasmodium yoelii circumsporozoite protein: vaccinia, pseudorabies, and salmonella transformed with circumsporozoite gene. | in an attempt to induce a protective cytotoxic t-cell mediated immunity against sporozoites of plasmodium yoelii, the gene encoding the p. yoelii circumsporozoite (cs) protein was engineered into three live vectors: vaccinia, attenuated pseudorabies, and attenuated salmonella typhimurium. balb/c mice were immunized with 1-4 doses of 10(8) pfu of the vaccinia construct (ip), 3 doses of 10(5), 10(6) or 10(7) pfu of pseudorabies construct (iv), and 3 doses of 10(9) salmonella transformants (orally) ... | 1990 | 2094576 |
| a malaria sporozoite surface antigen distinct from the circumsporozoite protein. | monoclonal antibody nys4 recognizes a single 140 kda antigen on the surface of plasmodium yoelii sporozoites, an antigen which is distinct from the extensively characterized circumsporozoite (cs) protein. to more thoroughly characterize this additional surface component, a genomic expression library was screened with nys4 and an immunoreactive clone (m4) was obtained which expressed part of the antigen gene. the deduced amino acid sequence of the m4 peptide included two unique repetitive sequenc ... | 1990 | 2094580 |
| localization of cs and non-cs antigens in the sporogonic stages of plasmodium yoelii. | monoclonal antibodies (mabs) and colloidal gold probes were used to localize circumsporozoite (cs) protein and two unrelated polypeptides in developing oocysts and salivary gland sporozoites of the 17x (nl) strain of plasmodium yoelii. mabs nys1, nys2, and nys3 recognized different epitopes of the p. yoelii cs protein and produced similar patterns of immunolabelling on developing oocysts and sporozoites. a small percentage of oocysts contained developing sporoblasts and sporozoites that did not ... | 1990 | 2094581 |
| effect of ketotifen on the ultrastructure of the erythrocytic stages of plasmodium yoelii. | the effect on the morphology of plasmodium yoelii of ketotifen treatment was different from that of chloroquine and other antimalarial drugs. following administration of a low dosage of ketotifen, the parasite first developed a multilamellate pellicular complex which resembled a medullary sheath and then developed vacuoles and cavitations. the development of large multilamellate whorls consisting of a pellicular structure enclosing cytoplasm was the typical change which occurred. | 1990 | 2098914 |
| [study on the exoerythrocytic forms of plasmodium yoelii yoelii in rats and mice]. | sd rats and three strains of mice were infected with plasmodium yoelii yoelii by265 strain by intravenous inoculation of sporozoites via tail vein. liver tissues were taken 42 hours after infection and serial sections were made and stained by colophonium-giemsa method for microscopic examination. the ratio of the average value of major diameter/minor diameter of exoerythrocytic(ee)schizonts of plasmodium yoelii yoelii in rats and mice of icr/jcl, c57bl, km strains was 35.81 +/- 4.56 microns/29.7 ... | 1990 | 2099260 |
| experimental studies on combinations of pyronaridine/primaquine versus chloroquine/primaquine. | the toxicity of combined use of blood schizontocide pyronaridine (pnd) and primaquine (pq) in mice and rats was significantly lower than that of chloroquine (cq) plus primaquine (pq). pnd 1/2 ld50 (ca 600 mg/kg) in combination with pq reduced the toxic action of pq in mice, while cq 1/2 ld50 (ca 300 mg/kg) plus pq produced synergistic toxic effect. in animal models such as plasmodium yoelii sporozoite infection in mice and p. cynomolgi sporozoite infection in rhesus monkeys, the tissue schizonto ... | 1990 | 2127247 |
| antibody formation to low-dose antigen and plasmodium yoelii clearance by offspring of protein-depleted male and female mice. | primary and secondary immune responses to low doses of sheep red blood cells (srbc) were investigated in well-fed first-degree offspring of three groups of protein-deficient mice (pd) and in well-fed first-degree offspring of well-fed mice (nd). the offspring of malnourished males and malnourished females had the highest level of primary anti-srbc antibodies, followed by the offspring of well-fed males and malnourished females, which also had a significantly higher primary anti-srbc antibody tit ... | 1990 | 2134561 |
| structure of a plasmodium yoelii gene-encoded protein homologous to the ca(2+)-atpase of rabbit skeletal muscle sarcoplasmic reticulum. | a cation-transporting atpase gene of plasmodium yoelii was cloned from the parasite genomic library using an oligonucleotide probe derived from a conserved amino acid sequence of the phosphorylation domain of the aspartyl phosphate family of atpases. the complete nucleotide sequence was determined and it predicts a 126,717 mr encoded protein composed of 1115 amino acids. northern blot analysis revealed that the gene is transcribed during the asexual stages of parasite development. the p. yoelii ... | 1990 | 2150071 |
| two soluble antigens of plasmodium falciparum induce tumor necrosis factor release from macrophages. | the production of cytokines such as tumor necrosis factor (tnf) may contribute to the pathology of malaria. we showed previously that crude preparations of heat-stable exoantigens from parasite cultures induce the release of tnf in vitro and in vivo. when separated from the culture medium by affinity chromatography, in which immune immunoglobulin g was used as ligand, the mixture of exoantigens of plasmodium falciparum retained the capacity to induce the secretion of tnf, both by human monocytes ... | 1990 | 2201638 |
| [soluble protein and esterase isozyme analysis of adult female anopheles stephensi after plasmodium yoelii yoelii-infected blood meal]. | in this paper, the system of anopheles stephensi and plasmodium yoelii yoelii was used as animal model. the soluble protein and esterase isozymes of adult female mosquitoes at various times after taking noninfected and plasmodia-infected blood meal were investigated. the result shows that the amount of soluble protein in plasmodia-infected mosquitoes was lower than that in noninfected ones (p less than 0.01); the activity and electrophoretic patterns of est in infected mosquitoes being also diff ... | 1990 | 2208623 |
| [synthesis of 2-methyl-5-substituted phenoxy-primaquine and antimalarials activity]. | in searching for efficient, safe and radically curative agent and causal prophylactics for malaria, seven 2-methyl-5-substituted phenoxy-6-methoxy-8-(1-methyl-4-aminobutylamino)-quinolines (ii1-7) were synthesized and their antimalarial activities were compared with the corresponding 4-methyl substituted derivatives of primaquine. the starting material, 2-nitro-4-methoxy-5-bromo-acetanilide (iii), was prepared from p-methoxy aniline through acetylation, bromination and nitration. iii was then co ... | 1990 | 2239331 |
| experimental transfer of immunity to plasmodium yoelii nigeriensis from adult rats to baby rats. | 1990 | 2251247 | |
| the effects of host diet on plasmodium yoelii nigeriensis. | a comparative study carried out on infected mice to investigate the effect of host diet on plasmodium yoelii nigeriensis showed that concentrations of blood protein, hemoglobin, and erythrocytes began to decrease in infected mice on day 2 after inoculation and reached the lowest levels on day 8. the greatest decrease was among mice fed on protein-rich mouse cubes, whereas the least decrease was among mice fed on cassava meal. inflammation of the spleens and livers of infected mice also was notic ... | 1990 | 2254825 |
| parasite-induced processes for adenosine permeation in mouse erythrocytes infected with the malarial parasite plasmodium yoelii. | in mouse erythrocytes harbouring the malarial parasite plasmodium yoelii, three processes contributed to inward fluxes of adenosine, one of which is attributed to the native nucleoside transporter, because of the inhibitory effects of nitrobenzylthioinosine (nbmpr). new (parasite-induced) permeation processes of low nbmpr-sensitivity were (i) saturable fluxes with preference for the d enantiomer (d-ado) and (ii) apparently unsaturable fluxes that proceeded by a channel-like route without enantio ... | 1990 | 2264834 |
| effect of host-diet inadequacy on the course of infection of plasmodium yoelii nigeriensis. | investigations were conducted into the course of infection of plasmodium yoelli nigeriensis in mice fed on an inadequate diet. it was found that mice fed on a '1/2' diet were able to withstand infection with the parasite better than mice fed on a full diet or a 1/4' diet. the haemoglobin value of mice fed on a full, '1/2' and '1/4' diets dropped by 67.5%, 66.8% and 68.8% respectively, while their packed cell volume dropped by 27.1%, 28.9% and 31.2% respectively. no mortality was recorded for uni ... | 1990 | 2268567 |
| identification of the gene for a plasmodium yoelii rhoptry protein. multiple copies in the parasite genome. | serum from mice hyperimmune to plasmodium yoelii was used to screen a p. yoelii genomic dna library. antibodies selected from hyperimmune serum by lambda gt11 clone j7 or raised against a specific fusion protein or peptide produced a punctate pattern of immunofluorescence on fixed smears of parasitised erythrocytes and immunoprecipitated a 235-kda protein apparently identical to a rhoptry protein previously implicated in red cell invasion. the cloned dna hybridised to at least seven rsai fragmen ... | 1990 | 2270106 |
| irradiated sporozoite vaccine induces cytotoxic t lymphocytes that recognize malaria antigens on the surface of infected hepatocytes. | the observation that protective immunity induced by immunization with radiation attenuated plasmodium berghei and plasmodium yoelii sporozoites is dependent on cd8+ t lymphocytes in some strains of mice led us to speculate that immunization with sporozoites induces cytotoxic t lymphocytes (ctl) that recognize malaria antigens on the surface of malaria-infected hepatocytes. in this report we summarize a series of experiments that confirm this hypothesis. we first showed that when immune mice are ... | 1990 | 2283160 |
| host-parasite interactions and immunity to irradiated sporozoites. | we compare and contrast the results of immunizing mice with irradiated sporozoites of plasmodium berghei and plasmodium yoelii. host genetic control of protective immunity is different in the two rodent malarias. few mouse strains are strongly protected by p. yoelii sporozoites, while all are protected by p. berghei sporozoite immunization. the role of cd8+ t cells in the protective immune response to each of these malarias varies with the strain of mouse. moreover, a single strain will use a cd ... | 1990 | 2283161 |
| [the modelling of the development of plasmodium yoelli yoelli in different vertebrate hosts]. | outbred mice and inbred balb/c mice were used for simulating plasmodium yoelii yoelii (strain 265 by) development. when the infection is initiated by standardized blood cryosamples and in sporozoite infection in various vertebral hosts the infection develops likewise as regard to parasitemia cyclic recurrences, however, the magnitude of parasitemia peaks, time of their occurrence, its stabilization or attenuation are different, which to a great extent determines the period of gametocyte infectiv ... | 1990 | 2290393 |
| plasmodium yoelii nigeriensis circumsporozoite gene structure and its implications for the evolution of the repeat regions. | the circumsporozoite (cs) gene encodes the most immunogenic component of the plasmodial sporozoites. the immunodominant epitope-encoding domain of the cs gene shows sequences that are repeated in tandem. a detailed analysis of the cs repeats of certain closely related malaria parasites (strains of plasmodium cynomolgi, plasmodium knowlesi, and plasmodium vivax) showed that they evolve rapidly yet are well conserved within the gene. we were interested in studying whether the cs repeats of plasmod ... | 1990 | 2290446 |
| plasmodium yoelii: comparative antimalarial activities of dietary fish oils and fish oil concentrates in vitamin e-deficient mice. | feeding vitamin e-deficient diets containing either fish oils such as menhaden, salmon, or anchovy oil or fish oil concentrates based on n-3 ethyl esters or free fatty acids protected mice against plasmodium yoelii as indicated by decreased parasitemia and improved survival. the fish oil concentrates depressed plasma tocopherol levels more strongly in vitamin e-supplemented mice than the menhaden oil. the free fatty acid concentrate appeared to suppress parasitemia in vitamin e-deficient mice be ... | 1990 | 2311714 |
| sequence analysis upstream of the gene encoding the precursor to the major merozoite surface antigens of plasmodium yoelii. | 1990 | 2320061 | |
| effect of plasmodium yoelii infection on gaba metabolism of mouse brain. | plasmodium yoelii infection in albino mice decreased the activity of brain glutamic acid decarboxylase (gad) by about 30 and 48% in crude homogenate and its synaptosomal fraction, respectively. the decrease was evident from 20% parasitemia and remained more or less constant up to 80% parasitemia. the km values of gad in normal and infected animals were 1.2 x 10(-2) and 3.3 x 10(-2) mm, respectively, indicating a decrease in enzyme substrate affinity due to infection. the lowered gad activity ros ... | 1990 | 2332040 |
| the effects of chloroquine on the infectivity of chloroquine-sensitive and -resistant populations of plasmodium yoelii nigeriensis to mosquitoes. | subtherapeutic doses of chloroquine have been reported to enhance infectivity of drug-resistant plasmodium species to their vectors. in this investigation, plasmodium yoelii nigeriensis n67 strain showed enhanced infectivity to mosquitoes when stimulated by chloroquine. both sensitive and resistant clones were derived from the n67 strain by dilution, showing that this strain is polymorphic for the resistant trait. a resistant subline was derived by selection under drug pressure from a chloroquin ... | 1990 | 2362764 |
| role of dna-binding antibodies in kidney pathology associated with murine malaria infections. | we performed a series of studies to examine the sequential development of nephritis during murine malaria infections and to define the role of dna-binding antibodies in the associated pathology. serum levels of these antibodies were assessed throughout acute and chronic malaria infections. increased levels of double-stranded dna- and single-stranded dna-binding antibodies were initially detected in mice infected with plasmodium vinckei or plasmodium yoelii nigeriensis during the middle stages of ... | 1990 | 2365456 |
| antimalarial activity of a combination of 5-fluoroorotate and uridine in mice. | malarial parasites, in contrast to mammalian cells, utilize orotic acid more efficiently than uracil or uridine. recently, chloroquine-susceptible and chloroquine-resistant clones of plasmodium falciparum were shown to be inhibited by 5-fluoroorotate, with a 50% inhibitory concentration of 6 nm in vitro. mammalian cells were far less sensitive to 5-fluoroorotate, particularly in the presence of uridine. in this report, the antimalarial activity of 5-fluoroorotate was tested in vivo. initially, l ... | 1990 | 2386369 |
| cytotoxic t cells recognize a peptide from the circumsporozoite protein on malaria-infected hepatocytes. | irradiated malaria sporozoites can induce cd8+ t cells that are required for protection against infection. however, the parasite antigens targeted by this immune response are unknown. we have discovered a 16-amino acid epitope from the plasmodium yoelii circumsporozoite (cs) protein that is recognized by cytotoxic t cells from immune mice. lymphocytes stimulated with this peptide can kill p. yoelii liver stage parasites in vitro in an mhc-restricted, antigen-specific manner. thus, epitopes from ... | 1990 | 1689762 |
| immune responses to defined epitopes of the circumsporozoite protein of the murine malaria parasite, plasmodium yoelii. | we have investigated the immunogenicity of defined sequences of the circumsporozoite (cs) protein of the murine malaria parasite, plasmodium yoelii. a 21-ner synthetic peptide from the nonrepetitive region of the cs protein (position 59-79, referred to as py1) induced t cell proliferative responses in h-2d and, to a lesser extent, in h-2b mice. conversely, a synthetic peptide (referred to as py4) consisting of four (qgpgap) repeats of the p. yoelii cs protein, induced an antibody response only i ... | 1990 | 1695152 |
| complex transcription from the extrachromosomal dna encoding mitochondrial functions of plasmodium yoelii. | all tested members of genus plasmodium contain tandemly arrayed, transcribed, extrachromosomal dna with a unit length of 6.0 kb. this dna contains two open reading frames with potential to encode cytochrome c oxidase subunit i (cox1) and cytochrome b (cob) as well as fragments of rrna genes scattered on both strands. at least 10 discrete rna molecules transcribed during erythrocytic stages of a rodent malarial parasite, plasmodium yoelii, were recognized by the 6.0-kb dna probes. the rna molecul ... | 1990 | 1701017 |
| isolation and characterization of protective cytolytic t cells in a rodent malaria model system. | protective immunity against malaria is induced by immunization with irradiation-attenuated sporozoites. here we report the isolation of cytolytic t-cell (ctl) clones from balb/c (h-2d) mice immunized with either plasmodium berghei or plasmodium yoelii sporozoites. the epitopes recognized by these ctl can be mimicked by synthetic peptides corresponding to a homologous region in the cs proteins of both rodent malaria species. both peptides are recognized by the ctl in the context of the same mhc c ... | 1990 | 1704348 |
| peptide-primed cd4+ cells and malaria sporozoites. | we have mapped a t cell epitope in the circumsporozoite (cs) protein of the murine malaria parasite, plasmodium yoelii. a 21-mer synthetic peptide corresponding to the amino acid positions 59-79 (referred to as py1), induced specific proliferation in balb/c and c57bl/6 mice, and provided help for the production of antibodies to peptides from the repetitive region, (qgpgap)n, of the same cs protein, when mice were immunized with the py1 peptide conjugated to the repetitive peptide. long-term cd3+ ... | 1990 | 1704350 |
| characterization of a plasmodium falciparum epitope recognized by a monoclonal antibody with broad isolate and species specificity. | monoclonal antibody (mab) 7h8 raised against plasmodium yoelii reacted with a series of proteins from p. falciparum that range in molecular weight from 46 to 194 kda. by immunofluorescence assay, this mab reacted with all isolates of p. falciparum tested. mab 7h8 was used to screen a genomic expression library of asexual blood stage antigens of p. falciparum, malayan camp k+ and 7 independent clones were identified. these 7 clones were sequenced and the epitope recognized by mab 7h8 in the recom ... | 1990 | 1706114 |
| activities of pefloxacin and ciprofloxacin against experimental malaria in mice. | we investigated the in vivo antimalarial activities of pefloxacin and ciprofloxacin in swiss albino mice infected intravenously with 5 x 10(6) plasmodium yoelii n67 parasites 1 h before treatment. groups of 20 mice received a subcutaneous injection of 40, 80, or 160 mg of ciprofloxacin or pefloxacin per kg of body weight every 8 h for 3 days. parasitologic activity was assessed on day 4, and survival was assessed on day 21. control mice had a fulminant course with a parasitemia of 61.3% +/- 12.1 ... | 1990 | 1708223 |
| active and passive immunization against plasmodium yoelii sporozoites. | three subunit vaccines based on the major repeat, (qgpgap)n, and flanking regions of the plasmodium yoelii circumsporozoite protein were designed, produced, and tested. all were immunogenic, but none gave consistent protection against a 40-200 sporozoite challenge. to demonstrate that antibodies to p. yoelii cs protein could provide protection we established a passive transfer model. passive transfer of nys1, an igg3 mab against the p. yoelii cs protein, protected 100% of mice against challenge ... | 1990 | 1709834 |
| cd8+ cytolytic t cell clones derived against the plasmodium yoelii circumsporozoite protein protect against malaria. | immunization of balb/c mice with radiation-attenuated plasmodium yoelii sporozoites induces cytotoxic t lymphocytes (ctl) specific for an epitope located within the amino acid sequence 277-288 of the p. yoelii circumsporozoite (cs) protein. several cd8+ ctl clones were derived from the spleen cells of sporozoite-immunized mice, all displaying an apparently identical epitope specificity. all the clones induced high levels of cytolysis in vitro upon exposure to peptide-incubated mhc-compatible tar ... | 1991 | 1716146 |
| towards the design of heterovalent anti-malaria vaccines: a hybrid immunogen capable of eliciting immune responses to epitopes of circumsporozoite antigens from two different species of the malaria parasite, plasmodium. | the peptide cs.t3, corresponding to residues 378-398 of the plasmodium falciparum (pf) circumsporozoite (cs) protein sequence (except with cysteines 384 and 389 replaced by alanines), has been found to be almost universally recognized by human and mouse t lymphocytes. when colinearly linked to the repetitive b-lymphocyte-specific epitope (asn-ala-asn-pro)n of pf cs protein, cs.t3 induces t-helper activity for an anti-(asn-ala-asn-pro)n antibody response in mice of different haplotypes. we constr ... | 1991 | 1721043 |
| identification of a common plasmodium epitope (cpe) recognised by a pan-specific inhibitory monoclonal antibody. | a plasmodium falciparum genomic expression library was screened with a monoclonal antibody produced from mice infected with plasmodium yoelii. eleven unique clones were isolated all of which contained the sequence nknd, iknd or kknd. this sequence was confirmed as the epitope of m26-32 by testing a series of overlapping peptides and the allowable substitutions determined by testing the binding of m26-32 to peptides containing all possible single amino acid replacements of nknd. potential epitope ... | 1991 | 1723149 |
| antigenic analysis of plasmodium yoelii liver stages by fluorescence antibody assays. | little is known about the immune response against liver stage antigens which were first described for plasmodium falciparum. in order to provide a basis for experimental studies, we analysed antigenically the liver stages of plasmodium yoelii using sera of restricted specificity. several distinct fluorescence patterns could be described in maturing liver forms. one pattern was identified as corresponding to antigens specific to the liver phase which are also species specific. another pattern cor ... | 1991 | 1724570 |
| host resistance to murine malaria in mice exposed to the adenosine deaminase inhibitor, 2'-deoxycoformycin. | resistance to infection with the nonlethal rodent malaria parasite plasmodium yoelii 17xnl (py 17xnl) is mediated by humoral, t-cell and accessory cell activity. the purpose this study was to profile host resistance to infection with this organism in mice exposed to 2'-deoxycoformycin (2dcf), a potent adenosine deaminase (ada) inhibitor. inhibition of ada activity by 2dfc results in defective t-cell function and either suppression or augmentation of the humoral response, depending on whether 2dc ... | 1991 | 1761363 |
| [effect of alpha-difluoromethylornithine on sporogony of plasmodium yoelii]. | the effect of alpha-difluoromethylornithine (dfmo) on the sporogony of p yoelii was studied by electron microscopy. dfmo sugar solution was fed to female mosquitoes. scanning electron microscopy (sem) revealed that the oocysts were smaller and the surface of oocysts was uneven as compared with control. transmission electron microscopy (tem) showed that cytoplasm of the affected oocysts contained vacuoles and the multilamellate structures increased. the number of matrix cavitations and deformatio ... | 1991 | 1781292 |
| the use of nested pcr and southern blotting to confirm the presence of actin in plasmodium yoelli. | 1991 | 1794544 | |
| activity of dihydrofolate reductase inhibitors on the hepatic stages of plasmodium yoelii yoelii in vitro. | the effects of the dihydrofolate reductase inhibitors proguanil and chlorproguanil, their active metabolites cycloguanil and chlorcycloguanil, and pyrimethamine, against the hepatic stages of plasmodium yoelii yoellii were investigated in cultured balb/c mouse hepatocytes. proguanil was inactive at concentrations of 10(-8) m, whereas the other compounds were fully active at this and lower concentrations. chlorcycloguanil was the most active compound and almost completely inhibited schizont devel ... | 1991 | 1801335 |
| [effect of nitroquine on protein synthesis of plasmodium yoelii in vitro]. | the erythrocytic stages of plasmodium yoelii (by 265 strain) were incubated with nitroquine (0.2 pmol.l-1 - 20 mumol.l-1), cycloheximide (0.1-10 nmol.l-1) and aminopterin (0.2 pmol.l-1 - 20 mumol.l-1) during 8 h in vitro. the results showed that the incorporation of [3h]-isoleucine into the protein by plasmodium yoelii was inhibited by nitroquine (0.2 pmol.l-1) and cycloheximide (0.1 nmol.l-1), the inhibitory effect of nitroquine (ic50 = 0.16 nmol.l-1) was 397 times higher than that of cyclohexi ... | 1991 | 1807087 |
| the effects of extracts of enantia chlorantha in malaria. | the aqueous extract of the plant enantia chlorantha was found effective in suppressing plasmodium yoelii infection in mice if given orally in drinking fluid at 0.2-150 mg ml-1, but not if given by oral cannulation or subcutaneously. the animals given the extract in their drinking fluid survived for over 60 days. the ethanolic extract also was found to be effective in eliminating the parasites when administered subcutaneously in doses of 0.05-0.5 mg g-1. the chemoprophylactic action of the aqueou ... | 1991 | 1811435 |
| the 235 kd rhoptry protein of plasmodium yoelii. | a 235 kd rhoptry protein produced by the malaria parasite, plasmodium yoelii is the target of antibodies that protect mice against blood-stage challenge with the virulent ym strain. in the protected animals the parasites are confined to reticulocytes and the course of parasitaemia is reminiscent of an avirulent 17x strain infection. the dna coding for the rhoptry protein has been identified as a multigene family containing at least four members. sequence analysis of short dna clones has identifi ... | 1991 | 1820696 |
| possible involvement of platelets in plasmodium yoelii nigeriensis malaria infection in mice. | the possible involvement of platelets in the pathogenesis of malaria was examined by monitoring the changes in platelet function (bleeding time [bt] and thrombin time [tt]) concomitantly with changes in packed cell volume (pcv) and erythrocyte infection rate (eir) in plasmodium yoelii nigeriensis infection in mice. in untreated plasmodium-infected mice, there was a progressive reduction (day 1-7) in bt from 120.0 +/- 12.6 s to 77.5 +/- 5.9 s (p less than 0.005), a reduction in tt from 26.8 +/- 1 ... | 1991 | 1823881 |
| protection against malaria by vaccination with sporozoite surface protein 2 plus cs protein. | the circumsporozoite (cs) protein has been the target for development of malaria sporozoite vaccines for a decade. however, immunization with subunit vaccines based on the cs protein has never given the complete protection found after immunization with irradiated sporozoites. balb/c mice immunized with irradiated plasmodium yoelii sporozoites produced antibodies and cytotoxic t cells against a 140-kilodalton protein, sporozoite surface protein 2 (ssp2). mice immunized with p815 cells that had be ... | 1991 | 1827210 |
| role of host cellular response in differential susceptibility of nonimmunized balb/c mice to plasmodium berghei and plasmodium yoelii sporozoites. | we found balb/c mice to be on the order of 2,000 times more susceptible to plasmodium yoelii than plasmodium berghei sporozoites, as measured by the ability of these sporozoites to differentiate into microscopically detectable hepatic schizonts in the livers of immunologically naive mice. one of the factors that determine the relative insusceptibility of mice to p. berghei sporozoites is the innate cellular inflammatory response that the mice mount after injection with sporozoites. the cellular ... | 1991 | 1855974 |
| tnf inhibits malaria hepatic stages in vitro via synthesis of il-6. | we examined the capacity of murine recombinant tumor necrosis factor (rmtnf) to induce an inhibitory effect at the hepatic stage on malaria induced by plasmodium yoelii sporozoites. when injected three times, 1.0 micrograms of rmtnf was found to protect 78% of mice against a sporozoite challenge. in contrast, whatever the dose and the schedule of administration, no inhibition was observed when purified hepatocyte cultures were infected with p. yoelii. the addition of non-parenchymal hepatic cell ... | 1991 | 1878339 |
| status of hepatic heme and heme oxygenase during plasmodium yoelii nigeriensis infection in mice. | plasmodium yoelii nigeriensis infection in albino mice caused a significant increase in hepatic heme level, the increase being concomitant with a rise in parasitemia. this elevated heme was found to be associated with all the subcellular fractions except the cytosol, where its content remained unaltered. activity of heme oxygenase, the key enzyme responsible for catabolism of heme, also increased progressively with rise in parasitemia. treatment of normal mice with cobalt chloride [60 mg (kg bod ... | 1991 | 1884769 |