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malaria and the liver. 19853920137
[the fine structure of the blood stages of the piperaquine-resistant line of plasmodium berghei anka strain]. 19853915734
[development of piperaquine-resistant line of plasmodium berghei anka strain]. 19853915725
protection of athymic (nu/nu) balb/c mice against plasmodium berghei by splenocytes from normal (nu/+) balb/c mice. 19853915397
recent advances in malaria research: parasite biology, chemotherapy and host/parasite relationships. 19853914847
[pyronaridine--a new antimalarial drug]. 19853914406
glucan-induced immunity in mice against plasmodium berghei. 19853913389
[studies on antimalarials. xv. synthesis and antimalarial activities of some bis(2,4-diaminoquinazol-6-yl-substituted aminomethyl) aromatic derivatives]. 19853913278
[studies on analogs of qinghaosu. vii. the synthesis of ethers of bis(dihydroqinghaosu) and bis(dihydrodeoxyqinghaosu)]. 19853913276
[development of a piperaquine-resistant line of plasmodium berghei k 173 strain]. 19853913275
protective immunity to malaria: studies with cloned lines of plasmodium chabaudi and p. berghei in cba/ca mice. i. the effectiveness and inter- and intra-species specificity of immunity induced by infection.cba/ca mice were immunized by infection with cloned lines of plasmodium berghei (isolates anka, ksp-11). plasmodium chabaudi chabaudi (as, cb) or plasmodium chabaudi adami (ds) and then challenged with either homologous or heterologous parasites. protective responses were assessed in immune mice relative to the controls by their ability to (i) extend the time taken for the mean parasitaemia to reach a predetermined level (1% or 0.1%) (ii) reduce peak parasitaemia (iii) resolve the parasitaemia s ...19853912704
[drug resistance of malarial parasites and the methods for its determination].the problem of drug resistance of plasmodium falciparum, the causative agent of tropical malaria and its role in the general system of malaria control are discussed. the aspects of distribution of drug resistant strains of p. falciparum and the main principles of determination of the malaria causative agent sensitivity to antimalaria drugs are presented. the determination implies the use of various procedures for performing the tests under clinical conditions in vivo and various modifications of ...19853911876
[microsomal monooxygenase inhibitors as promising agents for overcoming the drug resistance of the malaria parasite].a relationship was found between resistance of malarial plasmodium to chloroquine and the increased activity of microsomal monooxygenases, metabolizing drugs in the parasite. a search for effective inhibitors of the enzymatic system was initiated. for this purpose inhibitory effects of 17 alpha-hydrodeoxycorticosterone (substance s), 21-acetate-17 alpha-hydroxydeoxycorticosterone (acetate of substance s), 4-bromomethyl-2,2,5,5-tetramethyl-3-imidazoline-3-oxide-1-oxyl (rbr), cu(lysine)2 on activi ...19853911572
[changes in the white blood indices in experimental malaria in mice]. 19853911038
synchronized erythrocytic schizogony and gametocytogenesis of plasmodium berghei in vivo and in vitro.both asexual and sexual development of plasmodium berghei was synchronized without chemical intervention using in vitro culture techniques. combined in vivo and in vitro experiments were performed on the relationship between age, morphology and maturity of gametocytes. schizogony took 22-23 h in the experiments. at 26 h post-invasion (p.i.) the first males became capable of exflagellation. by 20 h p.i. the first gametocytes were recognizable in giemsa-stained smears but the sex was hardly distin ...19853909068
guanosine triphosphate cyclohydrolase in plasmodium falciparum and other plasmodium species.gtp cyclohydrolase (ec 3.5.4.16), the first enzyme in the pteridine pathway leading to the de novo formation of folic acid, has been identified and isolated from the human malaria parasite, plasmodium falciparum. the enzyme was purified 200-fold by high performance size-exclusion chromatography on a tsk-g-3000 sw protein column. the molecular weight was estimated at 300 000. optimal enzyme activity was observed at ph 8.0 and 42 degrees c. the km for gtp was 54.6 microm. products of the enzyme re ...19853908934
plasmodium berghei: oxidant defense system.glutathione oxidant defense system protects the erythrocyte from oxidative damage. this defense system was studied in mouse erythrocytes infected with plasmodium berghei and in isolated parasites. the efficiency of this system was found to be increased in parasitized erythrocytes compared to the normal erythrocytes. the increase in the components of the oxidant defense system in the parasitized cells could result from parasitic addition to these components. this defense system present in the par ...19853908136
the chemotherapy of rodent malaria, xxxix. ultrastructural changes following treatment with artemisinine of plasmodium berghei infection in mice, with observations of the localization of [3h]-dihydroartemisinine in p. falciparum in vitro.ultrastructural changes were followed in plasmodium berghei after the treatment of the mouse host with a single 10 mg kg-1 dose of artemisinine (qinghaosu). after 30 minutes, changes in the limiting and other membranes of the parasite were seen, together with alterations in ribosomal organization and endoplasmic reticulum. no changes were noted in digestive vacuoles or pigment, but nuclear membrane blebbing developed after one hour and segregation of the nucleoplasm after three hours. further de ...19853907556
chloroquine induces oxidative lysis of plasmodium berghei parasitized red blood cells. 19853907546
[criteria and circumstances of viability of gametocytes of plasmodium berghei]. 19853907543
the delivery of exoerythrocytic parasites of plasmodium berghei: a hormone controlled process. 19853907538
studies on the loss of sexual capacity in the anka isolate of plasmodium berghei and the reversibility of the process. 19853907527
[the effects of artemether on serum igg and spleen weight in mice]. 19853907273
synthesis of quinoline-mannich bases of possible antimalarial activity.for possible antimalarial activity, a series of some 4-substituted aminoquinoline mannich bases (5a-e) was synthesized. the antimalarial evaluation showed that compound 5b was active against plasmodium berghei in mice at a dose of 100 mg/kg.19853906678
immunity to an attenuated variant of plasmodium berghei: role of some non-specific factors.plasmodium berghei xat, an attenuated variant of lethal p. berghei, causes a resolving infection in balb/c mice from which they recover in about 3 weeks. the parasitaemia displays an early peak at about 5 days, followed by a steep drop in parasite number associated with the appearance of degenerating forms inside mature erythrocytes; the parasites remaining are inside reticulocytes. by contrast, no degenerating parasites were seen in infections caused by the virulent parent, which was mainly con ...19853906521
the development of plasmodium ookinetes in vitro: an ultrastructural study including a description of meiotic division.ookinetes have been cultured in vitro using modifications to the method of weiss & vanderberg (1977). significant improvements in technique were produced by culture in medium at ph 8.4 and at a blood dilution at or over 1/10. ookinetes produced were infective to mosquitoes by membrane feeding techniques. ultrastructural analyses were made of nuclear, cytoskeletal, crystalloid and microneme development. the first intranuclear division in the zygote has been recognized as meiosis. chromosome conde ...19853906519
development of plasmodium berghei ookinetes in the midgut of anopheles atroparvus mosquitoes and in vitro.plasmodium berghei ookinete formation in vitro and within the midgut of susceptible anopheles atroparvus were compared. no significant morphological differences were seen, except that in vitro development was more synchronized and less degenerating forms occurred. in vitro ookinete yields were 4-31 times higher and less variable than those in vivo. mosquitoes of a susceptible and of a refractory line of a. atroparvus were simultaneously fed on the same host or via a membrane with the same suspen ...19853906518
cytosolic protein kinase activity associated with the maturation of the malaria parasite plasmodium berghei.seven cytosolic phosphoproteins with relative molecular masses of 110, 58, 52, 46, 38, 36 and 34kda and isoelectric points between 4.2 and 5.0 are identified from the rodent malaria parasite plasmodium berghei. similar patterns of phosphorylated proteins are obtained from parasite cytosol after incubation of intact infected erythrocytes with [32p]orthophosphate, or from parasite cytosol incubated with [gamma-32p]atp. the characteristics of the phosphorylation reaction are similar to the previous ...19853906392
antimalarial agents. 1. alpha-santonin-derived cyclic peroxide as potential antimalarial agent.an alpha-santonin-derived cyclic peroxide (7) related to qinghaosu (1) has been synthesized and tested for antimalarial activity in vitro against the chloroquine-resistant (smith) isolates of plasmodium falciparum as well as in vivo against plasmodium berghei in mice and was found to be devoid of activity.19853906128
identification of the meiotic division of malarial parasites.zygotes of plasmodium berghei were cultured 15-25 h in vitro to yield mature infective ookinetes. samples taken in the first 5 h of culture were examined by electron microscopy. meiotic figures were detected in the nuclei of the zygotes. threadlike leptotene chromatids (chromosomes) condensed from attachment plaques on the nuclear envelope; chromatid pairing followed (zygotene), with synaptonemal complexes subsequently appearing (pachytene). these complexes persisted into metaphase but dissociat ...19853906103
fine structure of exoerythrocytic merozoite formation of plasmodium berghei in rat liver.the fine structure of exoerythrocytic merogony of plasmodium berghei was studied after perfusion-fixation of rat livers from 51 h post-inoculation onwards. meroblast formation was effected by clefts originating from the parasite plasmalemma and by fusion of vacuoles with each other. invaginations at the periphery resulted in labyrinthine structures providing the parasites with an enormous increase in surface area, which might facilitate exchange of metabolites. when the parasitophorous vacuole m ...19853906102
effect of plasmodium berghei infection on benzoic acid metabolism in mice.the metabolism of benzoic acid was studied in plasmodium berghei infected mice both in vitro and in vivo. results of in vitro studies showed a considerable decrease in the ability of the infected liver to detoxify benzoic acid by hippuric acid formation. the in vivo study showed that hippuric acid formation decreases with increasing parasitemia and the emergence of benzoyl-glucuronide. this new pathway stops operating with further increase in parasitemia.19853905430
[usefulness of the p. berghei antigen compared with those of p. vivax and p. malariae in evaluating the immune response in human malaria]. 19853903951
evidence against the red blood cell origin of mitogenic factors in mouse malarial infection.the mean [3h]thymidine incorporation in response to stimulation of spleen cells of malaria-immune and non-immune balb/c mice by normal mouse red blood cell culture supernatants were compared with unstimulated cultures of the same spleen cells. no significant difference was obtained between stimulated and unstimulated cultures for both immune and non-immune spleen cells. these findings do not support the hypothesis that erythrocyte-derived mitogenic factors occur in malarial infection.19853902628
changes in hematopoietic stem cells in bone marrow of mice with plasmodium berghei malaria.an impaired erythropoietic response to anemia has been noted in human patients with malaria and in rodents experimentally infected with plasmodium berghei. we have attempted to characterize the erythropoietic response in mice with a fatal p berghei infection, with particular emphasis on changes in marrow hematopoietic stem cells. mice infected with p berghei had dramatic decreases in bone marrow cellularity, erythroblasts, bfu-e, and cfu-e as early as 24 hours postinfection and before there was ...19853902119
the action of salinomycin-na and lasalocid-na on chloroquine- and mepacrine-resistant line of plasmodium berghei k 173-strain in wistar rats.salinomycin-na and lasalocid-na, two ionophorous antibiotics known for their anticoccidial activity, exhibit in vivo blood schizontocidal action on the plasmodium berghei keyberg 173 rc/m line that has a high level of resistance to chloroquine and mepacrine. salinomycin was found to have a greater effect than lasalocid on asexual stages of this line. trophozoites and schizonts were no longer found after a single dose of 20 mg/kg or five doses of 1.25 mg/kg of salinomycin whereas a single dose of ...19853901567
serum il-2 inhibitor in mice. i. increase during infection.serum from normal mice contains an inhibitor of interleukin-2 (il-2) which probably interacts directly with il-2. athymic mice and normal mice kept under specific pathogen-free conditions do not show this activity, whereas mice infected with malaria parasites have increased serum levels of inhibitor. this il-2 inhibitor may play an important part in regulating t-cell function.19853899918
malarial parasites complete sporogony in axenic mosquitoes.to obtain sporogonic stages of malaria free from microbial contaminants for in vitro studies, anopheles stephensi were reared under sterile conditions using a mosquito cell line as larval food. the adult females, kept in sterile humidified containers and allowed to engorge on parasitemic hamsters, supported the sporogonic development of the rodent malarial parasite plasmodium berghei. in 10 experiments, the proportion of infected mosquitoes varied from 0 to 92%, and the geometric mean number of ...19853899715
acute malaria prolongs susceptibility of mice to plasmodium berghei sporozoite infection.the fate of immune response against sporozoite stage in malaria infection was investigated. two groups (a and b) of mice were inoculated twice with infective sporozoites of plasmodium berghei. the mice in group a were maintained on chloroquine prophylaxis to prevent the sporozoite infection from causing malaria. group b animals on the other hand were allowed to develop acute malaria from the infection which was subsequently cured with chloroquine. upon examination for stage specific immune respo ...19853899429
a study of the uptake of chloroquine in malaria-infected erythrocytes. high and low affinity uptake and the influence of glucose and its analogues.a study of concentration- and substrate-dependence of chloroquine uptake has been carried out on mouse erythrocytes infected with the chloroquine-sensitive nk65 and the chloroquine-resistant rc strains of plasmodium berghei. the presence of drug binding sites of high and low affinity in such strains of p. berghei was confirmed. high affinity uptake sites in cells parasitized with chloroquine-sensitive and chloroquine-resistant parasites have similar characteristics, but in the sensitive strain t ...19853899119
[studies on analogs of qinghaosu (artean-nuin, artemisinine). iii. the synthesis of diacid esters and mono esters of dihydroqinghaosu]. 19853898722
pregnancy-induced recrudescences strengthen malarial immunity in mice infected with plasmodium berghei.a considerable proportion of mice lose acquired immunity to plasmodium berghei during the first pregnancy. immune parous mice, however, have a better immune status than virgin mice, the risk of loss of immunity during a subsequent pregnancy is greatly reduced, the capacity to clear parasites is enhanced, and the maintenance of immunity is less dependent on certain splenic functions. the establishment of improved immunity is dependent on the presence of proliferating parasites during the second h ...19853897957
perinatal immune priming in malaria: antigen-induced blastogenesis and adoptive transfer of resistance by splenocytes from rats born of plasmodium berghei infected females. 19853897956
detection of plasmodium falciparum using a radioimmunoassay based on a crossreacting, monoclonal anti-p. berghei antibody-p. berghei antigen system.an antibody binding-inhibition test is described, which allows the detection of p. falciparum in red blood cells (rbc) infected in vitro, using a crossreacting, monoclonal anti-p. berghei antibody and p. berghei coated microtiter plates. experiments carried out to determine the coating efficiency of various p. berghei and p. falciparum derived antigen preparations showed that intact, saponin freed p. berghei parasites and sonicated, rbc parasitized with p. falciparum had the highest binding acti ...19853897380
effect of a specific iron chelator, desferrioxamine on the host biochemistry and parasitaemia in mice infected with plasmodium berghei. 19853896872
transformation of sporozoites of plasmodium berghei into exoerythrocytic forms in the liver of its mammalian host.intrahepatocytic transformation in vivo of the rodent malaria sporozoite of plasmodium berghei, into the young trophic exoerythrocytic tissue stage was studied by immunofluorescence, light- and electron microscopy. the first 20 h of intracellular life were involved entirely in dedifferentiation with limited proliferation of organelles. from about 20 h onwards nuclear division commenced, rough endoplasmic reticulum became markedly expanded, and mitochondria increased in numbers. however, remains ...19853896506
free intraglomerular malarial antigens.infection with plasmodium berghei leads to a rapidly lethal disease in different strains of mice. nude athymic mice are not able to produce circulating antibodies (igg or igm) against plasmodial antigens. nevertheless, plasmodium-related antigens can be detected in the glomeruli of nude mice, in relation to the rising parasitaemia. this deposition is unrelated to the deposition of other immunoreactants (igg, igm or c3). the presence of the latter as well as the circulating auto-antibodies did no ...19853896290
electron microscopic studies on the interaction of rat kupffer cells and plasmodium berghei sporozoites.the interactions between plasmodium berghei sporozoites and kupffer cells in rat liver were studied by transmission electron microscopy. between 10 and 45 min after inoculation, sporozoites were found in the process of entering kupffer cells and inside phagolysosomes. the sporozoites entered the kupffer cells by phagocytosis as determined by the presence of pseudopods and local accumulations of aggregated microfilaments and the resulting exclusion of other organelles in the phagocyte cytoplasm b ...19853895767
nimbolide, a constituent of azadirachta indica, inhibits plasmodium falciparum in culture.the terpenoid lactone nimbolide, the structure of which has been unambiguously established, was found to inhibit plasmodium falciparum in culture with a moderate potency. the ec50 against the parasite line k1 from thailand was approximately 2.0 microm (0.95 microgram/ml). the ec50 of crude aqueous extract of azadirachta indica var. siamensis (sadao tree), was 115 micrograms/ml, and of crude ethanol extract was 5.0 micrograms/ml. since nimbolide is a major constituent in these extracts, it could ...19853895455
plasmodium berghei: the influence of blood volume changes on the malaria-induced anemia in balb/c mice.malaria-induced anemia exceeds that attributable to direct parasite destruction of erythrocytes. since spleen and liver weights increase significantly, hemodilution may account for part of this excessive anemia. to determine the role of hemodilution in the etiology of anemia, vascular volumes were measured with evans blue and isotope dilution techniques. the evans blue dilution technique showed that blood volume increased 20%, in infected balb/c mice. however, when blood volume was measured with ...19853892956
a possible role for natural killer cells in providing protection against plasmodium berghei in early stages of infection.beige mutant mice, which are deficient in natural killer (nk) cells, exhibited a significantly higher parasitaemia than the parental c57bl/6 strain between days 4 and 10 after infection with plasmodium berghei. within 8-12 days after infection 70% of beige mice were dead but no deaths occurred in the parental strain until day 16. the median survival time of the beige mice (10 days) was significantly lower than that of the parental strain (22 days). it appears that nk cells may be protective in t ...19853891603
use of a monoclonal, anti plasmodium berghei antibody, cross reacting with p. falciparum, for the detection of p. falciparum in in vitro infected blood.this report describes an immunoradiometric assay for plasmodium falciparum in infected blood, based on a cross-reacting monoclonal antibody (mab) raised against p. berghei. in this assay, binding of the mab to intact p. berghei parasites coated on microtiter plates is inhibited by solubilized p. falciparum infected red blood cells. the use of p. berghei parasites in conjunction with monoclonal antibodies should facilitate the development of an inexpensive and reproducible test for the immunodiag ...19853891600
comparative studies on thymidylate synthetase from p. berghei and mouse reticulocytes.partially purified thymidylate synthetase from plasmodium berghei and mouse reticulocytes was characterized. the mol. wt of the enzyme from p. berghei was about twice that from mouse reticulocytes. the optimum ph of the enzyme from p. berghei was found to be 6.5-7.5 while that from the host was 7.0-8.0. the enzyme from p. berghei was more susceptible to ph denaturation than the enzyme from reticulocytes. the enzyme from both sources differed in their km values for substrates. the enzyme from ret ...19853891213
malaria immunization--a zimbabwean perspective.a great deal of activity is being focused on the possibility of developing an effective vaccine for malaria. drug resistance is the main problem. of the new drugs under examination, only meflaquine, a quinine analogue, is at the stage of a clinical trial and even here it appears that resistance may be a problem. this review summarizes the current state of research on malaria immunization and adds some zimbabwean perspectives. natural immunity to malaria is directed against the blood stages o ...19853891094
qinghaosu-induced changes in the morphology of plasmodium inui.the ultrastructural changes induced by the administration of the antimalarial drug, qinghaosu, were studied in monkeys (macaca assamensis) infected with plasmodium inui. significant changes, notably mitochondrial swelling within the parasites but not within host cells, were first observed 2.5 hr after exposure to qinghaosu. this suggests that the target of qinghaosu may be the parasite's mitochondria, as occurs with primaquine. this is in contrast to the most widely used antimalarial drug, chlor ...19853890573
in vitro infectivity of cryopreserved plasmodium berghei sporozoites to cultured cells.plasmodium berghei sporozoites frozen in mem (eagle) medium supplemented with 10% hydroxyethyl starch and 50% normal mouse serum retained 0.5% infectivity to cultured hepatoma cells, compared to 6.8% before freezing. this demonstrates that frozen-thawed sporozoites can be used in in vitro investigations of the exoerythrocytic malarial parasite and means that when large numbers of sporozoites are available, they may be frozen and preserved for later use.19853890283
plasmodium berghei: gluconeogenesis in the infected mouse liver studied by 13c nuclear magnetic resonance.using 13c nuclear magnetic resonance, we have compared the gluconeogenic activity of perfused livers isolated from normal starved mice and mice highly parasitized with plasmodium berghei, using [2-13c]pyruvate as substrate. in both types of livers, 13c labeling of glucose carbons occurred in positions 1, 2, 5, and 6. the equal proportions of [1,6-13c]- and [2,5-13c]glucose in livers from malarial and normal mice suggests that pyruvate enters the gluconeogenic pathway directly and, to an equal ex ...19853888649
qinghaosu (artemisinin): an antimalarial drug from china.the herb artemisia annua has been used for many centuries in chinese traditional medicine as a treatment for fever and malaria. in 1971, chinese chemists isolated from the leafy portions of the plant the substance responsible for its reputed medicinal action. this compound, called qinghaosu (qhs, artemisinin), is a sesquiterpene lactone that bears a peroxide grouping and, unlike most other antimalarials, lacks a nitrogen-containing heterocyclic ring system. the compound has been used successfull ...19853887571
primaquine and lysosomotropic amines inhibit malaria sporozoite entry into human liver cells.the binding and entry of plasmodium berghei sporozoites to human hepatoma hepg2 cells is inhibited in a dose-dependent manner by primaquine, chloroquine and other lysosomotropic amines. the site of action of these agents appears to be the hepatoma cell itself, not the sporozoite. while this inhibitory effect of primaquine is rapidly reversible, the precise mechanism responsible for this effect is not presently known.19853887157
gametocytogenesis and ribosomal rrna gene organisation in the rodent malarias plasmodium chabaudi and plasmodium berghei.a cloned plasmodium berghei (anka) isolate was syringe passaged repeatedly to generate a line that was non-infective to anopheles stephensi. ribosomal gene organisation of this non-infective line was then compared to its infective ancestor. dna was also prepared from asexual parasites and gametocytes of p. chabaudi and the arrangement of the rrna genes of this species was studied. although macrogametocytes have many more ribosomes than microgametocytes, this increase does not appear to stem from ...19853887155
[comparative ultrastructural study of the process of hemoglobin degradation by p. berghei (vincke and lips, 1948) as a function of the state of maturity of the host cell].by serial sectioning and 3d reconstruction we have been able to demonstrate that the type of system for hemoglobin digestion in two strains of plasmodium berghei, n and rc, is dependent on the maturity of the host cell. in parasites growing in erythrocytes, both systems for the endocytosis of hemoglobin-micropinocytosis and the cytostomal system (i.e. a cytostome budding a cytostomal tube that releases food vacuoles)-are fully functional and produce a great quantity of residual pigment. parasite ...19853886896
a double screening trial for the development of drugs against theileria sergenti in cattle using babesia rodhaini and plasmodium berghei in mice. 19853884864
survival of plasmodium berghei in dead hosts. 19853884763
folate antagonists. 21. synthesis and antimalarial properties of 2,4-diamino-6-(benzylamino)pyrido[3,2-d]pyrimidines.the synthesis and antimalarial activity of a series of 2,4,6-triaminopyrido[3,2-d]pyrimidines (4) is described. several 6-substituted benzylmethylamino analogues were more active against trophozoite induced plasmodium berghei in mice than the corresponding quinazoline analogues. these agents, however, are cross-resistant to other antifolate compounds and are thus of limited potential as human agents.19853881585
plasmodium berghei: ectopic antibody synthesis in splenectomized rodents.jirds (meriones unguiculatus) were able to maintain acquired antimalaria immunity independent of the spleen approximately 4 months after initial infection. the memory cells appeared to become peripheralized, and persist outside the spleen for +/- 10 months if no further antigenic stimulus is applied. with regular stimulation, immunity was maintained indefinitely. in immune splenectomized jirds, the secondary, splenic germinal center function appeared to be taken over by cellular infiltrates in t ...19853881267
the effect of malaria infection on primaquine elimination in the isolated perfused rat liver.most antimalarial drugs are eliminated by hepatic metabolism. however, the influence of malaria infection on the hepatic elimination of these drugs has not been examined. in the present study the elimination of the antimalarial primaquine has been examined in isolated perfused rat livers (iprl) of malaria-infected sprague-dawley rats (90-110 g) (mi group; n = 6) and age- and weight-matched healthy rats (control group; n = 7). iprl preparations for the mi group were established 12-15 days after r ...19873814168
murine malaria decreases hemopoietic stem cells.the causes of anemia and immunosuppression, major outcomes of malaria, are not well established. this study was undertaken to investigate whether erythropoietin (ep) production is adequate and whether the hemopoietic stem cells (cfu-s) were affected during the course of infection. groups of female balb/c mice infected with plasmodium vinckei vinckei, plasmodium berghei, or plasmodium chabaudi adami were exposed to five hours of simulated altitude equivalent to 22,000 ft. plasma samples were coll ...19873801660
synthesis, antimalarial activity, and quantitative structure-activity relationships of tebuquine and a series of related 5-[(7-chloro-4-quinolinyl)amino]-3-[(alkylamino)methyl] [1,1'-biphenyl]-2-ols and n omega-oxides.a series of 5-[(7-chloro-4-quinolinyl)amino]-3-[(alkylamino)methyl] [1,1'-biphenyl]-2-ols and n omega-oxides was prepared from the substituted 1-phenyl-2-propanones proceeding through the 5-nitro[1,1'-biphenyl]-2-ols, the corresponding amino, and acetamido derivatives to the n-[5-[(alkylamino)methyl]-6-hydroxy[1,1'-biphenyl]-3-yl]acetamides and final condensation with 4,7-dichloroquinoline or the n-oxide. in a quantitative structure-activity relationship study first run on 28 and later expanded ...19863712383
functional drug targeting to erythrocytes in vivo using antibody bearing liposomes as drug vehicles.covalent attachment of anti-erythrocyte f(ab')2 to the liposome surface has recently been shown to considerably enhance the liposome binding to erythrocytes in vivo. these antibody bearing liposomes have now been found quite effective as vehicles for delivering the antimalarial drug, chloroquine, to erythrocytes in plasmodium berghei-infected mice. this demonstrates the usefulness of antibody targeted liposomes as carriers for site-specific drug delivery.19873675583
structurally distinct, stage-specific ribosomes occur in plasmodium.two structurally distinct nuclear genes code for cytoplasmic small subunit ribosomal rna's in the parasite plasmodium berghei. stable transcripts from one of the ribosomal rna genes are found almost exclusively in those stages of the life cycle that develop in the mosquito. when the parasite infects the mammalian host, transcripts from the second gene become the predominant small subunit ribosomal rna species.19873672135
antimalarial activity of new water-soluble dihydroartemisinin derivatives.the usefulness of sodium artesunate (3), a water-soluble derivative of artemisinin (1), is impaired by its poor stability in aqueous solution. to overcome the ease of hydrolysis of the ester group in 3, a new series of derivatives of dihydroartemisinin (2) was prepared in which the solubilizing moiety, which contains a carboxylate group, is joined to dihydroartemisinin by an ether rather than an ester linkage. the new derivatives were prepared in good yield by treatment of dihydroartemisinin wit ...19873669021
modifications of primaquine as antimalarials. 4. 5-alkoxy derivatives of primaquine.thirty-two 5-alkoxyprimaquines have been synthesized and evaluated as blood schizonticides (plasmodium berghei, mouse) and tissue schizonticides (plasmodium cynomolgi, monkey). several of these compounds were extremely active in both screens. such a broad spectrum of antimalarial efficacy offers the possibility of a single drug that could cure the various relapsing and nonrelapsing malarias.19873599024
plasmodium berghei: cloning of the circumsporozoite protein gene.a dna fragment encoding the carboxy terminal 80% of the plasmodium berghei circumsporozoite protein was selected from a genomic dna expression library. sequencing revealed that the p. berghei circumsporozoite protein was similar in overall structure to circumsporozoite proteins from other malaria species, although the central repeat region was unique in comprising two different blocks of tandem peptide repeats: 11 eight amino acid repeats with predominant sequence dpappnan were followed by 16 tw ...19873556207
[detection of a system of microsomal monooxygenases in the rodent malaria parasite plasmodium berghei].a microsomal fraction from the cells of the malaria parasite of rodent plasmodium berghei was obtained. the spectral properties of microsomal preparations suggest that p. berghei microsomes contain cytochromes b5 and p-420. electrophoretic separation of microsomal proteins revealed the presence of proteins whose molecular mass corresponds to nadph-cytochrome c reductase, cytochrome p-450 and epoxide hydratase. the activities of nadph-cytochrome c reductase and benzpyrene hydroxylase were determi ...19873555625
peripheral vascular pathophysiology of plasmodium berghei infection: a comparative study in the cheek pouch and brain of the golden hamster.four- to six-week-old hamsters were infected with 1.5 x 10(7) plasmodium berghei-parasitized hamster red blood cells by intraperitoneal injection. cheek pouch circulation was observed microscopically in the anesthetized animal; the brain and contralateral pouch were collected for histopathologic examination on days 3-12 post-challenge. cheek pouch vascular lesions, observed in vivo, appear to involve three phenomena; early (beginning 3-4 days) adhesion of pigment-laden mononuclear cells to endot ...19873555136
depression of virus-specific cytotoxic t-cell responses during murine malaria.mice with self-limiting p. yoelii or fatal p. berghei infections exhibited a markedly impaired ability to mount specific splenic cytotoxic t-lymphocyte responses to immunization with infectious ectromelia (ev), vaccinia (vac), or lymphocytic choriomeningitis viruses (lcmv). lymph node responsiveness, however, was not impaired. primary ctl responses were depressed in mice immunized 7 days after p. berghei infection, while in p. yoelii-infected mice, depressed responses were detected only during t ...19873554117
[evaluation of larvicidal effects of bacillus thuringiensis var. israelensis (serotype h-14) and bacillus sphaericus preparations and the susceptibility of adult mosquitoes to malarial plasmodia]. 19873553885
synthesis and antimalarial effects of 4-[(7-chloro-4-quinolinyl)amino]-2-[(diethylamino)methyl] -6-alkylphenols and their n omega-oxides.a series of 4-[(7-chloro-4-quinolinyl)amino]-2-[(diethylamino)methyl]-6-alkylphenols and their n omega-oxides were synthesized by the condensation of 4,7-dichloroquinoline and 4,7-dichloroquinoline n omega-oxide with appropriately substituted 4-amino-2-[(diethylamino)methyl]-6-alkylphenol dihydrochlorides. the latter precursors were prepared in a six-step synthesis starting from available 2-alkylphenols. several of the title compounds display potent antimalarial activity in mice.19873553599
effect of dosage and route of inoculation on parasitaemia in white rats and guinea pigs to plasmodium berghei infection. 19873553360
preliminary observations on development of quinine sulphate resistance in plasmodium berghei. 19863552759
[ultrastructural study on the effect of pyronaridine on the erythrocytic stages of chloroquine-resistant strain of plasmodium berghei]. 19863552291
[effects of qinghaosu on the surface structure of erythrocytes infected with plasmodium berghei and the erythrocyte-free parasites]. 19863552290
efficacy of murine malaria sporozoite vaccines: implications for human vaccine development.as part of a study of potential vaccines against malaria, the protective efficacy of sporozoite subunit vaccines was determined by using the plasmodium berghei murine malaria model. mice were immunized with recombinant dna-produced or synthetic peptide-carrier subunit vaccines derived from the repetitive epitopes of the plasmodium berghei circumsporozoite gene, or with radiation-attenuated sporozoites. immunization with subunit vaccines elicited humoral responses that were equivalent to or great ...19873551073
[experimental malaria: contamination of strains and experimental animals by eperythrozoon coccoides]. 19863551022
[production of an attenuated strain of p. berghei by secondary passages through mice receiving vitamin e]. 19863547060
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
an ultrastructural study of the effects of mefloquine on malaria parasites.the ultrastructural changes induced by the administration of a recently developed antimalarial drug, mefloquine, were studied in mice infected with plasmodium berghei and human erythrocytes infected with p. falciparum in vitro. pronounced changes which occurred in both experiments comprised swelling of the parasites' food vacuoles with gradual loss of pigment granules, which did not form clumps as occurs with chloroquine. these findings suggest that the malarial parasites' food vacuole is the ta ...19873544894
comparative studies on the infectivity of plasmodium berghei gametocytes and ookinetes for gnotobiotic and xenobiotic anopheles stephensi.previous studies indicated that gnotobiotic anopheles stephensi mosquitoes were less susceptible to infection with plasmodium berghei than xenobiotic ones (munderloh and kurtti, 1985). groups of 100 to 200 mosquitoes were fed on infected hamsters, heparinized gametocytemic blood (via a membrane feeder), and in vitro-formed ookinetes suspended in blood (membrane feeder). xenobiotic a. stephensi were readily infected by all 3 routes. gnotobiotic mosquitoes consistently acquired infection after eng ...19863543280
use of a dna probe to measure the neutralization of plasmodium berghei sporozoites by a monoclonal antibody.a specific dna probe has been used to quantify the neutralizing effects of monoclonal antibodies (3d11) against the circumsporozoite protein of plasmodium berghei sporozoites. the amount of parasite dna was measured in the livers of norway brown rats at the peak of proliferation of the exoerythrocytic forms (eef). in vitro treatment of 1.5 x 10(5) sporozoites with 0.36 microgram/0.5 ml of whole 3d11 igg neutralized about 90% of the sporozoite infectivity. when the dose was 3.6 micrograms no sign ...19873543124
macrophage cytotoxicity in lethal and non-lethal murine malaria and the effect of vaccination.we investigated the development of cell-mediated immunity in lethal and non-lethal malarial infections by assaying the cytotoxic activity of spleen cells for l929 tumour cells at different times after infection of mice with the lethal p. berghei, a lethal variant of plasmodium yoelii and the non-lethal p. yoelii and p. chabaudi. in all cases the cytotoxicity increased to a peak during the first week and then diminished but the time of the peak varied with the infection; its activity was lowest w ...19863542317
[electron microscopic study on the invasion of erythrocytes by plasmodium berghei merozoites]. 19863542282
intranuclear development of plasmodium berghei in liver cells. 19863542241
occurrence of exoerythrocytic schizonts in the liver, adrenal glands and endocardium of mice infected with erythrocytic stages of plasmodium berghei. 19863541848
qinghaosu resistance in rodent malaria.resistance to qinghaosu (artemisinin) developed rapidly in a chloroquine-resistant line of plasmodium yoelii (ns) passaged in mice, but was not produced in chloroquine-sensitive p. berghei. development of resistance took place in an apparently stepwise fashion. after removal of drug selection pressure some resistance was lost which was regained rapidly within three passages when drug pressure was reapplied. the resistant qs line was cross-resistant to two reduced derivatives of artemisinin but n ...19863541309
[main results of carrying out the branch program to develop and put into practice the scientific bases for the complete and permanent elimination of malaria in the ussr]. 19863540556
sequence of the small subunit ribosomal rna gene expressed in the bloodstream stages of plasmodium berghei: evolutionary implications.we have determined the complete nucleotide sequence of the coding region of the small subunit rrna gene expressed by bloodstream stages of the apicomplexan plasmodium berghei. it is 2059 nucleotides long. elements contributing to its relatively large size are all concentrated in regions known to be variable in length among eukaryotes. in a phylogenetic tree constructed from pairwise comparisons of eukaryotic small subunit rrna sequences, the apicomplexan line branches at a rather early point in ...19863540280
characteristics of membrane protein phosphorylation in plasmodium berghei-infected mouse erythrocytes.membrane protein phosphorylation in plasmodium berghei-infected erythrocytes was studied by incubating intact cells with (32p)orthophosphate and incubating isolated membrane with (gamma-32p)atp. phosphorylated proteins were detected by autoradiography after sodium dodecylsulfate (sds)-polyacrylamide gel electrophoresis or isoelectric focusing followed by gel electrophoresis. new phosphorylated proteins were found in membrane from infected erythrocytes, including a protein with electrophoretic mo ...19863540278
characterization of monoclonal antibodies directed against erythrocytic stage antigens of plasmodium berghei.monoclonal antibodies recognizing various facets of the malaria parasite plasmodium berghei and of the infected erythrocyte were obtained after generation of hybridomas between spleen cells from immunized mice and myeloma cells. the monoclonal antibodies were characterized by enzyme-linked immunosorbent assay, indirect immunofluorescence, immunoprecipitation of [35s]methionine-labeled proteins and immunoblotting. the most readily identified antigen was a parasite surface-associated protein of 23 ...19863539609
[a formula for estimating the half-life of a drug]. 19863538772
intra erythrocytic differentiation of plasmodium berghei. 19863538746
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