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hepatic acid hydrolases of albino rats, mastomys natalensis and albino mice during plasmodium berghei infection.changes in liver acid hydrolase activities during the infection of albino rats, mastomys or mice with plasmodium berghei are described. b-glucosidase, b-galactosidase and n-acetyl-b-d-glucosaminidase exhibited widely different responses with acid phosphatase and cathepsin-b the least responsive and are likely to be causally related to immunity of animals.19853921400
rhoptry secretion of membranous whorls by plasmodium berghei sporozoites.electron microscopy of sporozoites of the rodent malaria parasite, plasmodium berghei, reveals electron-dense multilaminate membranous whorls within components of the rhoptry-microneme complex after fixation with tannic acid in conjunction with glutaraldehyde. this multilaminate material, which has a dark line to dark line periodicity of approximately 5 nm, appears to be secreted from the sporozoite since it is also found adhering to the sporozoite's external surface. the material may function i ...19853925131
interactions of plasmodium berghei-infected erythrocytes with complement.incubation of radioactively labeled parasitized (plasmodium berghei) erythrocytes (pe) with adherent peritoneal exudate cells in the presence of 10% (v/v) fresh mouse serum (nms) resulted in the uptake of a proportion of radioactive material (pe). inactivation of the added serum by heat or zymosan treatment resulted in diminished uptake of radioactivity. these results suggest that pe activated complement. incubation of fresh nms with pe reduced the hemolytic complement level of the serum as show ...19853925133
effects of p-aminobenzoic acid, methionine, threonine and protein levels on susceptibility of mice to plasmodium berghei.the effects of dietary p-aminobenzoic acid (paba), protein, methionine and threonine on plasmodium berghei infection in mice were investigated. animals were fed diets containing 12 or 20% casein supplemented with paba (0 or 2 mg/kg diet), methionine (0 or 15 mg/g casein) and threonine (0, 7.5, 27.5 or 47.5 mg/g casein). percent mortality was lower in rats fed diets without paba than in those fed diets containing paba. all further experiments were conducted without supplemental paba. while the me ...19853934351
activities of the tetrahydrofuran derivative, ba-41,799, against plasmodium cynomolgi infections in rhesus monkeys.ba-41,799, a tetrahydrofuran derivative that at one time attracted considerable interest as an antimalarial agent because of a combination of structural novelty with activities against infections with plasmodium berghei and plasmodium berghei yoelii in mice, has been evaluated for its capacities to effect prophylaxis and radical cure in rhesus monkeys challenged or already infected with sporozoites of the drug-susceptible ro strain or the pyrimethamine-resistant ro/pm strain of plasmodium cynomo ...19853985599
4-substituted 5-[m-(trifluoromethyl)phenoxy]primaquine analogues as potential antimalarial agents.five 4-substituted 5-[m-(trifluoromethyl)phenoxy]primaquine analogues were synthesized and tested for radical curative activity against plasmodium cynomolgi in rhesus monkeys and for blood schizonticidal antimalarial activity against plasmodium berghei in mice. in addition, they were evaluated for causal prophylactic antimalarial activity against plasmodium berghei yoelii in mice. one compound, 4-ethyl-5-[m-(trifluoromethyl)phenoxy]primaquine (2b), showed radical curative activity equivalent to ...19854067985
sulfur-interrupted 8-amino side chain analogues of 4-methyl-5-[m-(trifluoromethyl)phenoxy]primaquine as potential antimalarial agents.two isomeric sulfur-interrupted 8-amino side chain analogues of 4-methyl-5-[m-(trifluoromethyl)phenoxy]primaquine (2) were prepared and tested for antimalarial activity. the compounds were evaluated for blood schizonticidal activity against plasmodium berghei in mice and radical curative activity against plasmodium cynomolgi in rhesus monkeys. in addition, they were evaluated for causal prophylactic activity against plasmodium berghei yoelii in mice. both compounds were more active and less toxi ...19854068013
immunoradiometric assay to measure the in vitro penetration of sporozoites of malaria parasites into hepatoma cells.we describe here an immunoradiometric assay to quantitate the in vitro invasion of hepatoma cells by sporozoites. the assay measures levels of circumsporozoite (cs) antigen that remain associated with the hepatoma cells after their incubation with the parasites. several observations show that these measurements reflect internalized rather than extracellular antigen. for example, when incubations were performed with nonviable parasites (sonicated or heated), or in the presence of metabolic inhibi ...19852981261
in vitro cultivation of the exoerythrocytic stage of plasmodium berghei in irradiated hepatoma cells.growth of cultures of human hepatoma cells was inhibited by exposure to doses of gamma irradiation as low as 1,000 rad., and the monolayers remained viable for up to 35 days. irradiated cells were at least as susceptible to plasmodium berghei sporozoite invasion as non-irradiated cells, and supported the entire exoerythrocytic cycle producing more infectious merozoites. irradiated cultures may have use for culture of human malarias, and drug studies requiring synchronous cultures.19852982289
acth-dependent modulation of malaria immunity in mice.tetracosactrin, a synthetic adrenocorticotrophic hormone (acth) analogue delivered by osmotic minipumps implanted s.c. in mice induced a dose-dependent increase of plasma corticosterone levels. in mice with an established immunity to plasmodium berghei the increase of the plasma corticosterone level due to tetracosactrin treatment correlated with loss of immunity against this malaria parasite. the observed plasma corticosterone levels associated with loss of malaria immunity were of the same ord ...19852987773
plasmodium berghei: inhibitors of ornithine decarboxylase block exoerythrocytic schizogony.dl-alpha-difluoromethylornithine and dl-alpha-monofluoromethyldehydroornithine methyl ester, inhibitors of ornithine decarboxylase, blocked exoerythrocytic schizogony of plasmodium berghei in mice and in cultured human hepatoma cells. these effects were reversed by exogenous administration of the polyamine, spermidine. the antimalarial drug, primaquine, the side chain of which is structurally analogous to a natural polyamine, did not enhance the activity of alpha-difluoromethylornithine or alpha ...19852990989
investigations of various extracts of morinda lucida for antimalarial actions on plasmodium berghei berghei in mice.morinda lucida extracts, the stem bark, the root bark and the leaves were screened for antimalarial activity in a "4-day schizontocidal test' against a chloroquine-sensitive strain of p. berghei berghei in mice. each extract was administered as a single daily dose on days 0, 1, 2 and 3 to mice that had received an intraperitoneal inoculum of 1 x 10(7) infected erythrocytes. each extract produced a degree of suppression of parasitaemia. the most promising result was obtained with chromatographic ...19852994438
effect of azadirachta indica on plasmodium berghei berghei in mice.azadirachta indica leaf extract has been investigated for antimalarial activity against drug sensitive strain of p. berghei berghei in mice. on administering the extract subcutaneously to infected mice in the "4-day schizontocidal test' 41.2% suppression of parasitaemia was observed. a similar observation was made when the extract was injected for 3 days before the animals were infected with the parasites, 21.7% chemosuppression was obtained. when treatment commenced after the infection had alre ...19852994439
lack of schizontocidal activity of three herbal decoctions on plasmodium berghei berghei in mice.this work reports the effects of three herbal decoctions on plasmodium berghei berghei in mice. the schizontocidal activity of each decoction was determined on an established infection using chloroquine as a standard and distilled water as control. also a repository study of the decoction was carried out in another group of mice. the three decoctions neither reduced parasitaemia nor prolonged the life of infected mice that received them.19852994440
screening of morinda lucida leaf extract for antimalarial action on plasmodium berghei berghei in mice.the leaf extract of morinda lucida collected in august was administered subcutaneously to albino swiss mice infected with p. berghei berghei. the schizontocidal activity on early infection was assessed by administering chloroquine (standard) distilled water or morinda lucida as single daily dose on day 0-3 to infected mice. on day 4 the degree of parasitaemia and percentage was determined in relation to control. its schizontocidal activity was also observed on an established infection by adminis ...19852994441
identification of a telomeric dna sequence in plasmodium berghei.a fragment of plasmodium berghei dna was cloned using a technique designed to select for telomeric sequences. the cloned fragment recognizes bal31-sensitive bands in p. berghei genomic digests. it contains at its distal end at least 70 tandem repeats of the heptanucleotide sequence ccctgaaa. the presence of natural single strand discontinuities in the telomeric regions of p. berghei dna is demonstrated by the selective incorporation of deoxyribonucleoside triphosphates in the absence of dnase. t ...19852998771
magnetic resonance studies of the pathophysiology of murine malaria. 19852999860
[inhibition of plasmodium berghei in rats infested with strongyloides ratti or trichinella spiralis; role of high blood corticosterone in reaction to the development of helminths].the plasma corticosterone induced in the rat by the development of strongyloides ratti or trichinella spiralis reaches a sufficient level of intensity to determine reticulocytopenia. the latter is linked chronologically to the inhibition of parasitemia in plasmodium berghei, which occurs when this protozoa develops at the same time as the nematodes, and seems to be the causal factor. this hypothesis may be verified by replacing the helminths with the corticotropic action of a.c.t.h. which causes ...19853002223
cytofluorimetric analysis of dna content in different life stages of plasmodium yoelii. 19852423000
re-examination of earlier work on repetitive dna and mosquito infectivity in rodent malaria.previous results, relating mosquito infectivity to percentage of repetitive dna in the genome of plasmodia, are re-examined in the light of the finding that a parasite line used in the previous studies and classified as plasmodium berghei nk65, was a mixed infection, where the major component appeared to be plasmodium yoelii. this conclusion was reached through cloning and isoenzyme typing of different clones. isoenzyme typing alone is not sufficiently sensitive to reveal contamination amounting ...19852863751
in vitro formation of ookinetes and functional maturity of plasmodium berghei gametocytes.in vitro formation of plasmodium berghei ookinetes was studied. gametocytes produced in vitro were obtained from heart and tail blood of swiss mice and from blood removed from mosquitoes directly after feeding on these mice. in vitro produced gametocytes were obtained from short-term cultures of the erythrocytic stages of p. berghei. reproducible ookinete production was obtained in medium rpmi 1640, ph 7.8-8.0, using in vivo and in vitro produced gametocytes. the morphology of developmental stag ...19852863802
the sustained release of pyrimethamine base or pyrimethamine pamoate from a biodegradable injectable depot preparation in mice.the pharmacokinetics and mass fate in mice, of pyrimethamine (425 mg kg-1 s.o.) administered subcutaneously either as the base (base) or the pamoate salt (pam) in an injectable oil mixture (benzyl benzoate-peanut oil 50:50 v/v) have been evaluated. maximum measured plasma pyrimethamine levels after base were attained within 24 h, and were twice as high as after pam. 25% of animals dosed with base died; among the survivors plasma drug levels fell rapidly below the minimum inhibitory concentration ...19852868095
[stability of drug resistance of a pyronaridine-resistant line of plasmodium berghei]. 19852943123
[effect of pyronaridine on ultrastructure of erythrocytic forms of plasmodium berghei in mice]. 19852945375
[response of the plasmodium berghei anka strain to some antimalarials]. 19852934947
[the effect of qinghaosu on the pfc and rfc of mice infected with plasmodium berghei]. 19852936520
partial cross-reactivity by suppressor cells induced during different experimental autoimmune diseases.following injection of rat red cells, mice develop anti-red cell autoantibodies and subsequently suppressor t cells specific for these. likewise, following recovery from non-lethal malaria, they develop suppressor t cells which suppress the anti-lymphocyte autoantibodies induced by lethal malaria parasites. neither type of suppressor cell affected non-autoantibody components of the response, nor a response to sheep red cells. however, there was variable but significant cross-suppression of the r ...19853156012
alpha-difluoromethylornithine inhibits the first part of exoerythrocytic schizogony of plasmodium berghei in rodents. 19863105475
[development of a qinghaosu-resistant line of plasmodium berghei anka and n strain]. 19863296654
the chemotherapy of rodent malaria, xl. the action of artemisinin and related sesquiterpenes.artemisinin (qinghaosu), a poorly soluble sesquiterpene lactone derived from the plant artemisia annua linn., and a number of more soluble, semi-synthetic derivatives are rapidly-acting blood schizontocides against plasmodium berghei and p. yoelii nigeriensis. an oily suspension of artemisinin given s.c. is more effective than aqueous suspensions. the activity is retained against lines resistant to primaquine, cycloguanil, pyrimethamine, sulphonamides, mefloquine and menoctone, but a highly chlo ...19863307655
surface plasmodium sugar-binding components evidenced by fluorescent neoglycoproteins.a sugar-binding component was shown to be present at the surface of endoerythrocytic plasmodium berghei and p. chabaudi stages and merozoites by means of a panel of neoglycoproteins using fluorescence microscopy and flow cytofluorometry. the protein nature of this material was ascertained by the loss of sugar-binding capacity upon trypsin treatment. this lectin-like protein primarily bound neoglycoprotein-borne n-acetylglucosamine and secondarily bound neoglycoprotein-borne alpha-d-glucose, beta ...19862941097
inhibition of development of exoerythrocytic forms of malaria parasites by gamma-interferon.a specific dna probe was used to study the effect of recombinant rat, mouse, and human gamma-interferon (gamma-ifn) on the course of sporozoite-induced malaria infections. in mice and rats infected with sporozoites of plasmodium berghei, mouse and rat gamma-ifn's strongly inhibited the development of the exoerythrocytic forms in the liver liver cells of the hosts, but not the development of the erythrocytic stages. the degree of inhibition of the exoerythrocytic forms was proportional to the dos ...19863085218
rapid repeated dna replication during microgametogenesis and dna synthesis in young zygotes of plasmodium berghei. 19863088783
dna synthesis in plasmodium berghei during asexual and sexual development.dna contents of individual stages of plasmodium berghei were measured by direct microfluorometry after feulgen-pararosaniline (so2) staining. sporozoites, intra-erythrocytic ringforms and trophozoites (until at least 15 h after invasion) are haploid and non-synthesizing dna. dna is synthesized just before and during schizogony, which takes 4-6 h. genome duplication and segregation are alternating events throughout this process. mature micro- and macrogametocytes have dna contents between the hap ...19863092048
l3t4+ t lymphocytes play a major role in the pathogenesis of murine cerebral malaria.the pathogenic importance of l3t4+ t cells in the development of murine cerebral malaria was demonstrated by the following observations. first, in vivo administration of an anti-l3t4 monoclonal antibody protected plasmodium berghei-infected cba mice from the development of neurologic symptoms and acute death. in contrast, injection with an mab directed against the ly.2+ t cell subset had no protective effect. second, thymectomized, irradiated, and bone marrow reconstituted (atxbm) cba mice did n ...19863093572
[suppression of chloroquine resistance in plasmodium berghei by using a microsomal monooxygenase inhibitor]. 19863093829
enhancing effects of rodent malaria on aflatoxin b1-induced hepatic neoplasia.the interaction between aflatoxin and malaria was tested for its usefulness as a model for hepatic tumor induction in rats. male buffalo rats which received aflatoxin b1 (afb1) followed by plasmodium berghei infection developed more preneoplastic lesions in the liver compared to those given afb1 alone. no preneoplastic lesions were found in the liver of control and malarial-treated animals. these findings suggest that the malarial parasite facilitates liver tumor development initiated by afb1 in ...19863095331
mitomycin-c is an unreliable inhibitor for study of dna synthesis in plasmodium.cytophotometric studies on dna synthesis during asexual and sexual development of plasmodium berghei contradicted earlier conclusions on dna synthesis in plasmodium which were largely based on experiments in which mitomycin-c had been used as a dna replication inhibitor. therefore, the effect of mitomycin on intra erythrocytic asexual development and on microgametogenesis, fertilization and zygote/ookinete development of p. berghei was studied in vitro. all dna-synthesizing stages (schizonts, ex ...19863095638
alpha-difluoromethylornithine induces protective immunity in mice inoculated with plasmodium berghei sporozoites.mice inoculated weekly with plasmodium berghei sporozoites while under treatment with alpha-difluoromethylornithine (dfmo), an inhibitor of ornithine decarboxylase, developed protective immunity against subsequent challenge with this parasite. the percentage of mice protected was similar whether dfmo alone (55%) or dfmo + chloroquine (65%) was used. with chloroquine alone, only 12% of mice were protected. this protection was long-lasting (at least six months). the immunity protected against spor ...19863097887
[effects of piperaquine on the fine structure of the erythrocytic stages of plasmodium berghei anka strain]. 19862954398
[delay in emergence of resistance to pyronaridine phosphate in plasmodium berghei]. 19862954424
[effects of artemether on red blood cell immunity in malaria]. 19862954426
plasmodium berghei-infected mice: lack of effect of meclizine and cimetidine on the development of pulmonary oedema.the involvement of histaminergic mechanisms in the pathogenesis of pulmonary oedema observed in plasmodium berghei-infected mice was investigated. histamine concentrations in plasma and whole blood of infected and normal mice were determined by radioenzymatic assay during the seven days of the infection. elevated plasma and whole blood histamine levels were found at the last stages of infection (sixth day and seventh day after ip injection of parasitized erythrocytes), showing a close temporal c ...19862888439
antigen-specific and mhc-restricted plasmodium falciparum-induced human t lymphocyte clones.we established and analyzed human t lymphocyte clones induced by crude plasmodium falciparum antigens of schizont-enriched asexual blood stages. peripheral blood mononuclear cells (pbmc) were stimulated for 6 days with antigen, and the t cell blasts were separated and were transferred to limiting dilution cultures with antigen, irradiated pbmc, and recombinant interleukin 2. the following observations were made. malaria antigen (m.ag) induced similar proportions of t blasts in pbmc from infected ...19862424980
development of a sporozoite malaria vaccine. 19862425647
[test of cross immunity in 3 strains of plasmodium berghei of different virulence in mus musculus cured of infection using thermal stress (+35 degrees c)]. 19862428277
circumsporozoite protein of plasmodium berghei: gene cloning and identification of the immunodominant epitopes.the gene encoding the circumsporozoite (cs) protein of the rodent malaria parasite plasmodium berghei was cloned and characterized. a cdna library made from p. berghei sporozoite rna was screened with a monoclonal antibody for expression of cs protein epitopes. the resulting cdna clone was used to isolate the cs protein gene from a lambda library containing parasite blood-stage dna. the cs protein gene contains a central region encoding two types of tandemly repeated amino acid units, flanked by ...19862432395
antimalarial agents, 2. artesunate, an inhibitor of cytochrome oxidase activity in plasmodium berghei.the activity of the cytochrome oxidase, which is located in the plasma and the nuclear and the food-vacuole-limiting membranes as well as in the mitochondria of the trophozoites of plasmodium berghei, was inhibited completely by sodium artesunate, an antimalarial drug, in vitro at 1 mm and in vivo at 100 mg/kg iv. this enzyme appears to be a target for the antimalarial mechanism of action of artesunate and qinghaosu.19863009719
purification and characterization of plasmodium berghei dna topoisomerases i and ii: drug action, inhibition of decatenation and relaxation, and stimulation of dna cleavage.it has recently been suggested that topoisomerases could be important targets for drugs used in several diseases. this prompted us to purify and characterize the topoisomerases i and ii present in the erythrocytes of protozoan parasites of the genus plasmodium, the causative agent of malaria, in order to later use these enzymatic systems in antimalarial drug assays. the topoisomerases were purified from plasmodium berghei, a parasite of mouse red cells. the plasmodium topoisomerase ii consists o ...19863011062
effects of antimalarial drugs on oxygen consumption by erythrocytes infected with plasmodium berghei: an esr study.oxygen consumption in mouse erythrocytes infected with plasmodium berghei has been followed by electron spin resonance (esr) spectroscopy of nitroxide radical spin probes. the parasitized red cell suspension is mixed with the spin probe ctpo (3-carbamoyl-2,2,5,5-tetramethyl-3-pyrrolin-1-yloxy) in a closed chamber. oxygen consumption is monitored by the increasing resolution of the superhyperfine splittings of the spin label. the antimalarial drugs quinacrine, primaquine, and quinine are shown to ...19863012241
plasmodium berghei: reaction of sporozoites with chemically and enzymatically modified hepatoma cells.plasmodium berghei sporozoites were observed to react with human hepatoma (hepg2) target cells which had been fixed with methanol, formaldehyde, or glutaraldehyde. the reaction consisted of attachment of sporozoites to the fixed target cells and the release of circumsporozoite protein which bound to target cell areas adjacent to the attachment sites. treatment of fixed target cells with 0.1 n h2so4 at 80 c, neuraminidases, neuraminidase plus galactose oxidase or inclusion of transferrin, orosomu ...19863013669
cephalo-adrenal interactions in the broader context of pragmatic and theoretical rhythm models.some of the literature on modeling of biological rhythms with mathematical, physical, chemical, biochemical, in vivo and in vitro oscillations is succintly annotated. the need for biologic models that account for the interaction of 3 or more periodic entities is indicated, documented and illustrated, with emphasis on the cephalo-adrenal network of rodents. patterns of interaction, in this context, involve attenuation, no-effect and/or amplification by a third entity, the modulator, of the effect ...19863015508
homologous telomeric sequences are present in different species of the genus plasmodium.the telomeric sequence cloned from plasmodium berghei (see m. ponzi et al. (1985) embo j. 4, 2991-2995) was tested for species specificity. a telomeric and a subtelomeric fragment of the cloned insert served as separate, labelled probes on pulsed field gradient electrophoretical patterns and on genomic digests from the rodent malarias plasmodium yoelii, plasmodium chabaudi and from the human malaria plasmodium falciparum. results indicate that the subtelomeric fragment, abundantly represented in ...19863024000
identification of distinct accumulation sites of 4-aminoquinoline in chloroquine sensitive and resistant plasmodium berghei strains.we report the synthesis of an analogue of chloroquine (cqa) which can be used as a probe to visualize accumulation of 4-aminoquinoline by electron microscopy. a mouse monoclonal antibody against cqa was raised and used for immunodetection by the protein-a gold method on ultrathin cryosections, of cqa treated parasites. we demonstrate that in a p. berghei chloroquine(cq)-sensitive strain (n strain) the chloroquine analogue used accumulates in the endocytic vacuoles where hemoglobin (hb) degradati ...19863545836
[production of an attenuated strain of p. berghei by secondary passages through mice receiving vitamin e]. 19863547060
[experimental malaria: contamination of strains and experimental animals by eperythrozoon coccoides]. 19863551022
[effects of qinghaosu on the surface structure of erythrocytes infected with plasmodium berghei and the erythrocyte-free parasites]. 19863552290
[ultrastructural study on the effect of pyronaridine on the erythrocytic stages of chloroquine-resistant strain of plasmodium berghei]. 19863552291
preliminary observations on development of quinine sulphate resistance in plasmodium berghei. 19863552759
plasmodium berghei malaria: effects of acute-phase serum and erythrocyte-bound immunoglobulins on erythrophagocytosis by rat peritoneal macrophages.acute-phase serum (aps) collected from plasmodium berghei-infected rats inhibited phagocytosis of trypsinized rat erythrocytes and of erythrocytes from p. berghei-infected rats. macrophages (m phi) incubated with aps or heat-aggregated acute-phase serum (haaps) for 6 h, followed by 18 h incubation in serum-free medium, exhibited significantly higher levels of phagocytosis than m phi similarly cultured but with normal rat serum. when aps was present at the time of assay, it inhibited erythrophago ...19863510164
the effects of cortisone on immunity during chronic rodent malaria.the temporal effects were studied of a single dose of hydrocortisone acetate on the development and expression of immune responses to plasmodium berghei in mice with chronic infections. cortisone administration prior to primary infection reduced malaria-specific secondary humoral and cellular responses, as well as the ability to survive parasite challenge. once protective humoral immunity was established after chemotherapy of primary infection, cortisone treatment did not disrupt its expression. ...19863511746
membrane fluidity changes in p. berghei-infected erythrocytes, investigated with a specific plasma membrane fluorescent probe.trimethylamino-diphenylhexatriene (tma-dph), a novel hydrophobic fluorescent probe with relevant photophysical properties for fluorescence anisotropy measurements in phospholipidic membranes, specifically labels the plasma membranes of whole living-cells, unlike earlier commonly used probes such as 1,6-diphenyl-1,3,5-hexatriene (dph) and anthroyloxy fatty acids, which invade all hydrophobic regions of the cell. using tma-dph, it was shown that mouse malaria parasite plasmodium berghei induced a ...19863511915
effect of macrophage activation on phagocyte-plasmodium interaction.we investigated the effect of both immune and normal sera on the binding of free plasmodium berghei by resident and activated macrophages. resident macrophages bound plasmodia to a greater extent than did activated macrophages, regardless of treatment. resident macrophages bound free plasmodia, predominantly trophozoites, in the presence of normal serum by a mechanism inhibited by n-acetylglucosamine and n-acetylmannosamine. macrophages activated through treatment with propionibacterium acnes (" ...19863512432
plasmodium berghei sporozoite invasion is blocked in vitro by sporozoite-immobilizing antibodies.a monoclonal antibody directed against the circumsporozoite protein on the surface of plasmodium berghei sporozoites inhibited sporozoite motility in vitro. these immobilized sporozoites could adhere to but not invade target cultured cells. other sporozoite-immobilizing agents also inhibited sporozoite invasion into cultured cells and did not prevent sporozoite adherence. these results indicate that sporozoite invasiveness is associated with sporozoite motility. thus, the immobilizing effect of ...19863512436
use of a two-sited monoclonal antibody assay to detect a heat-stable malarial antigen in the sera of mice infected with plasmodium yoelii.antigens, circulating in the blood during malarial infections, have been implicated in immune protection, immunosuppression, and immune-complex formation. we used a monoclonal antibody (mab 7h8) to identify an antigen (ag-7h8) in the sera of mice infected with plasmodium yoelii. the major form of the antigen has a molecular weight of approximately 120,000 in p. yoelii, with minor components of 220,000; 65,000 to 75,000; and 45,000. ag-7h8 remains antigenic after boiling for 5 min. a two-sited as ...19863512438
2-acetylpyridine thiosemicarbazones. 12. derivatives of 3-acetylisoquinoline as potential antimalarial agents.a series of 3-acetylisoquinoline thiosemicarbazones and their related thiosemicarbazides was prepared for evaluation as potential antimalarial agents. the former were synthesized by the reaction of 3-acetylisoquinoline with methyl hydrazinecarbodithioate to give methyl 3-[1-(3-isoquinolinyl)ethylidene]hydrazinecarbodithioate, iv. displacement of the s-methyl group of this intermediate by the requisite amines gave 3-acetylisoquinoline thiosemicarbazones, v. the corresponding thiosemicarbazides, i ...19863513773
the ribosomal genes of plasmodium. 19863514510
immunosuppression in murine malaria: role of activated macrophages.the role of macrophages in immunosuppression which develops during plasmodium berghei infection in mice has been studied. the transfer of activated macrophages (or their extracts) from the infected mice with low parasitaemia (less than 10%) to uninfected mice enhanced their humoral response to sheep red blood cells (srbc) as indicated by the number of splenic igm and igg plaque-forming cells (pfc). in contrast, when macrophages obtained during higher parasitaemia (16%) were used, significant inh ...19863516130
[omega-aminoacyl compounds against malaria].investigations on diphenylthioether derivatives led to compounds with a high antimalarial (p. berghei) activity. 58 new compounds were synthetisized in order to study structure-efficacy relationships. general formula: efficacy was optimal in compounds with r1 = no2. some of such compounds were at least half as effective as chloroquine and fully effective against drug resistant strains of p. berghei. but also other radicals proved to be suitable as long as s was not replaced by o. but two dipheny ...19863516160
synthesis and anthelmintic activity of 2,2'-disubstituted 5,5'-dibenzimidazolylsulfides and sulfones.a number of substituted diphenylsulfides and sulfones (4-11) and 2,2'-disubstituted-5,5'-dibenzimidazolyl sulfides and sulphones (12-19) have been synthesized starting from 5-chloro-2-nitroacetanilide and (3) 4,4'-dichlorodiphenyl sulfone (9), respectively. among the compounds tested against ancylostoma ceylanicum in hamsters and hymenolepis nana in rats and mice, 14, 15, 18 and 19 removed 100% of the worms at an oral dose of 25 mg/kg x 1 to 250 mg/kg x 3. some of the compounds were tested for t ...19863518728
oxygen consumption in plasmodium berghei-infected murine red cells: a direct spectrophotometric assay in intact erythrocytes.a spectrophotometric assay has been devised to measure oxygen consumption non-invasively in intact murine red cells parasitized by plasmodium berghei. the method uses oxyhemoglobin in the erythrocytes both as a source of oxygen and as an indicator of oxygen consumption. spectra of intact cells show broad peaks and sloping baselines due to light-scattering. in order to ascertain the number of varying components in the 370-450 nm range, the resolution of the spectra was enhanced using fourier tran ...19863518808
the establishment of plasmodium berghei in mosquitoes of a refractory and a susceptible line of anopheles atroparvus.the events between the ingestion of plasmodium berghei-infected mouse blood and the establishment of the ookinetes in the epithelium of the midgut in refractory (r) and susceptible (s) anopheles atroparvus are described. simultaneously fed, fully engorged female mosquitoes were randomly assigned to dissection at 22, 28, 32, 48 h and 10 days (controls) after the infective feed (post-infection: p.i.). serial transverse sections of 6 micron were cut. every 10th section was studied. the maturation o ...19863521118
increased sensitivity in antigen detection during immunoblot analysis resulting from antigen enrichment via immunoprecipitation.the sensitivity in antigen detection during immunoblot analysis is greatly increased if the antigen is first immunoprecipitated from the crude extract before electrophoresis and transfer to nitrocellulose. not only does the method allow detection of antigens which are minor components of crude mixtures or antigens which cannot be radiolabeled, but the method also resolves problems, such as high background, which are often associated with immunoprecipitation. also, by modifying the method, whethe ...19863521383
plasmodium berghei: reduction of the mouse's specific lymphoproliferative response in relation to corticosterone and pregnancy.spleen cells from mice immune to plasmodium berghei exhibited a significantly increased in vitro proliferative response to parasitized reticulocytes compared to spleen cells from normal mice. the specific response to malaria antigen was decreased in spleen cells from pregnant immune mice in contrast to the nonspecific response to the mitogen phytohemagglutinin. addition of mouse serum to spleen cell cultures of immune mice depressed both the phytohemagglutinin and the specific proliferative resp ...19863522263
trypsin-sensitive plasmodia in the liver of post-infection rats and rhesus monkeys.kupffer cells from the liver and erythrocytes from peripheral blood were collected at the post-patent period from albino rats infected earlier with plasmodium berghei and rhesus monkeys infected earlier with p. cynomolgi var. bastianelli or p. knowlesi. the cells were subinoculated into individual normal recipients. these recipients subsequently showed parasitaemia in their circulation. the parasites present in kupffer cell preparations were found to be sensitive to trypsin treatment, while thos ...19863522381
immune t-cells and their lymphokines enhance phagocytosis of merozoites by macrophages. 19863522764
infectivity of plasmodium berghei sporozoites measured with a dna probe.a 2.3 kb, 32p-labeled repetitive dna probe of plasmodium berghei was used to measure the amount of parasite dna in the liver of norway brown rats and mice infected with sporozoites. standard hybridization curves were obtained by probing different amounts (100 pg to 1 microgram) of p. berghei dna immobilized on nitrocellulose filters. host dna did not interfere with hybridization specificity and sensitivity. a 100-fold increase in hepatic parasite dna was detected between 25 h post-infection and ...19863523238
protective immunity to malaria. studies with cloned lines of plasmodium chabaudi chabaudi and p. berghei in cba/ca mice. ii. the effectiveness and inter- or intra-species specificity of the passive transfer of immunity with serum.serum was obtained from cba/ca mice infected, reinfected or superinfected with parasites taken one or two syringe passages from cryopreserved reference stabilates derived from cloned lines of the as or cb isolates of p.c. chabaudi. serum was also collected from mice superinfected with parasites derived from a cloned line of p. berghei ksp-11. when injected into normal syngeneic recipients subsequently challenged with homologous or heterologous parasites, these sera mediated some or all of the fo ...19863523398
sialic acid analysis and tritium-labelling of sialoglycoproteins of mouse erythrocytes infected with plasmodium berghei.schizont-infected red blood cells (si-rbc) from plasmodium berghei-infected mice contain between 2 and 10 times as much sialic acid as uninfected rbc from the same blood (99-550 micrograms/10(10) rbc versus 33-65 micrograms/10(10) rbc). total rbc samples from infected animals containing up to 63% ring- and trophozoite-infected cells had identical sialic acid contents to purified rbc samples (of less than 3% parasitaemia) from the same blood (52-64 micrograms/10(10) rbc). we conclude that rbc con ...19863526260
catalase activity in red cell and liver of mice infected with plasmodium berghei.hydrogen peroxide (h2o2) has been incriminated to have an oxidative killing malaria parasite. as p. berghei-infected mouse red cells generated h2o2 in vivo, this would result in the alteration of catalase status of the host. the present study was undertaken to determine catalase activity in red cells and liver of mice infected with p. berghei. the studies were performed in 17 samples of infected red cells as well as 20 samples of the normal red cells. results showed that the catalase activity in ...19863526580
plasmodium berghei: histology, immunocytochemistry, and ultrastructure of the placenta in rodent malaria.the pathological changes associated with malarial infection in pregnancy were studied in rats and mice infected with plasmodium berghei at different stages of gestation. histopathological and ultrastructural studies of infected placentae near term in both species revealed disruption of architecture with gross thickening and necrosis of cells in the labyrinthine zone and fibrosis of the trilaminar trophoblast separating the maternal and fetal circulations. in the mouse, the extent of histopatholo ...19863527738
protection of mice against plasmodium berghei infection by a tuftsin derivative.in plasmodium berghei infections, the mortality rate and parasitaemias were significantly reduced and the mean survival time was considerably enhanced by pretreating the animals with a tuftsin derivative, thr-lys-pro-arg-nh-(ch2)2-nhcoc15h31. this effect of the modified tuftsin was further increased upon its incorporation in the liposome bilayer. these results indicate that tuftsin and its derivatives may prove useful in enhancing nonspecific host resistance against protozoan infections.19863527754
carrier-linked primaquine in the chemotherapy of malaria.the antimalarial effect of intravenously administered primaquine (pq) can be improved and its toxicity diminished by linking it to a macromolecular carrier protein. a thiol-containing primaquine derivative 8-[[4-(2-amino-3-mercaptopropionamido)-1-methylbutyl]amino]-6- methoxyquinoline was synthesized. this compound could readily be linked via a disulfide bond to a carrier protein containing (pyridyldithio)propionate groups. the derivative was coupled to serum albumin as well as to serum albumin ...19863528491
[effect of dichroa febrifuga l. on chloroquinsensible and chloroquinresistant malaria parasites]. 19863528514
[isoenzyme typing of strains of plasmodium berghei and plasmodium yoelii]. 19863530087
[probable loss of chloroquine resistance in plasmodium berghei inoculated in mus musculus previously irradiated with sublethal doses (300 r) of x-rays]. 19863530088
[activity of 2 aminoglycoside antibiotics in plasmodium berghei infection in mus musculus]. 19863530089
[effect of maintaining a strain of plasmodium berghei anka on gametogenesis]. 19863530148
[parasitological and serological observations during pregnancy in mice infected with plasmodium berghei]. 19863530149
screening azadirachta indica and pisum sativum for possible antimalarial activities.solvent-free extracts obtained from the leaves of azadirachta indica and pisum sativum were screened for antimalarial action using plasmodium berghei in mice. four days of oral dosing with 500 mg/kg and 125 mg/kg of the methanol extract of a. indica showed a parasite suppression which was statistically significant although all test animals died after 5 days, just 1 day longer than the untreated control group. a 50 mg/kg oral dose of the aqueous extract of p. sativum was found to have significant ...19863531729
[effect of vitamins d and e on the development of plasmodium berghei infection in mice]. 19863531794
effects of mycobacterium bovis bcg, bacterial lipopolysaccharide and hydrocortisone on the development of immunity to plasmodium berghei. 19863532283
influence of malarial infection on the maternal-foetal relationship in pregnant mice.pregnant mice infected on gestation day (gd) 6 with plasmodium berghei showed a more rapid rate of increase in parasitaemia than mice infected later in pregnancy or non-pregnant controls. all mice infected on gd 6 were dead by the 7th post-infection day. pregnant mice infected on gd 13, in contrast, had similar rates of parasitaemia and mortality as non-pregnant controls and 50% delivered normally, the foetuses were absorbed in 20% and 30% died before parturition. the pups born to mice infected ...19863533019
natural cytotoxicity for plasmodium berghei in vitro by spleen cells from susceptible and resistant rats.the susceptibility of 30-day-old rats to plasmodium berghei infection has traditionally been ascribed to the higher levels of circulating blood reticulocytes for which p. berghei has a predilection. however, spleen cells soon develop natural cytotoxicity for p. berghei which may account, in part, for the increased natural resistance of older rats. spleen cells from normal 30- or 50-day-old rats were cultured overnight with erythrocytes parasitized by p. berghei and then injected into mf1 mice. s ...19863533764
antibody-dependent and -independent cytotoxic activity of spleen cells for plasmodium berghei from susceptible and resistant rats.antibody-dependent cell cytotoxicity (adcc) mediated by spleen cells from 30- or 50-day old rats against 51cr-labelled rat erythrocytes parasitized by plasmodium berghei in the presence of anti-p. berghei antibody showed only slight age differences. however, in the absence of specific antibody, the total cell-mediated cytotoxicy (cmc) per spleen was four times higher in the spleen cells from 50-day-old rats compared with those from 30-day-old rats. cmc accounted for about 50% of total cytotoxic ...19863533765
superoxide dismutase and catalase in the murine malaria, plasmodium berghei: content and subcellular distribution.plasmodium berghei, a murine malaria, lacks endogenous superoxide dismutase (sod). instead it appears to take up and concentrate sod from its host cell, the erythrocyte. we now demonstrate that the adopted host enzyme is localized in granules which are probably lysosomes. in addition, isolated p. berghei parasites contain only low levels of catalase, probably as a result of contamination of the preparation with host cell material. thus, the cytosol of this organism appears to be deficient in enz ...19863535681
plasmodium berghei: relative immunogenicity of infected reticulocytes and infected oxyphilic red blood cells.hyperbleeding of mice 1 day before and 1 day after infection with plasmodium berghei resulted in a more aggravated infection. parasitemia rose significantly faster, but the mean survival time of these mice was not significantly different from control mice. at day 5 of infection, parasites were almost exclusively in reticulocytes in contrast to control infections in which parasites were found in oxyphilic erythrocytes at day 5 after infection. purified parasitized reticulocytes taken from hyperbl ...19863536567
effect of inhibitors on glucose transport in malaria (plasmodium berghei) infected erythrocytes. 19863536772
the course of plasmodium berghei infection in mice subjected to variable dosages of the parasite and the peak parasitaemia obtained accordingly. 19863537159
organization of the exoerythrocytic stage of the rodent malaria parasite plasmodium berghei. a cytochemical study.with the osmium tetroxide-zinc iodide impregnation technique the visualization of the internal organization of the exoerythrocytic form of the rodent malaria parasite plasmodium berghei was improved. osmium impregnation leached the ground matrix of the parasite thereby displaying a system of intermediate-sized filaments. because microtubules are only present as part of the mitotic spindle and as remnants of the sporozoite cytoskeleton, the observed intermediate-sized filaments comprise most of t ...19863537327
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