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trial of antimalarial potential of extracts of artemisia annua grown in myanmar. 19911755047
detection of mature malaria infections in live mosquitoes.a method has been developed which detects malaria parasites in the salivary glands of live anopheles stephensi. the method exploits the sugar feeding behaviour of the mosquito and requires only routine western blotting techniques on nitrocellulose membrane (ncm). infectivity can be determined without any direct manipulation of individual mosquitoes. female a. stephensi were infected with the rodent malaria parasite, plasmodium berghei, and after 14-16 d were starved of fructose overnight (12-18 ...19911755048
[the computer processing of data from experimental research on malaria. 2. the quantitative characteristics of parasitemia dynamics].models of simple and modified logistic function have been used for the quantitative characteristics of malaria infection development. the approach could be successfully used, which was demonstrated on experimental infection dynamics in rodents during parasitemia assessment both in absolute and logarithmic scales. regression analysis of experimental data and choice of an optimal form of logistic equation are performed with the help of specially elaborated software. the calculated values of logist ...19911770882
[the search for new antiparasitic agents. 4. the study of the antimalarial activity of n-(halogen naphthyloxy)-2-hydroxy-3,5-dihalogen benzamides].antimalarial activity of 10 n-(haloidnaphthyloxy)-2-hydroxy-3,5-dihaloidbenzamide compounds earlier synthesized as potential anthelmintics has been studied. it has been shown that antimalarial activity is typical only of amides of 2-hydroxy-3,5-diiodinebenzoic acid.19911770883
antiamoebic and antiplasmodial activities of alkaloids isolated from strychnos usambarensis.seven alkaloids isolated from strychnos usambarensis have been assessed for in vitro activities against entamoeba histolytica and plasmodium falciparum and for in vivo activity against plasmodium berghei in mice. strychnopentamine and 3',4'-dihydrousambarensine were highly active against p. falciparum in vitro, but were inactive and non-toxic against p. berghei in vivo. usambarensine, usambarine, and 18,19-dihydrousambarine were highly active against e. histolytica in vitro, but were less active ...19911775573
studies using a recombinant vaccinia virus expressing the circumsporozoite protein of plasmodium berghei.a recombinant vaccinia virus was constructed which expressed the circumsporozoite protein of plasmodium berghei. four different strains of mice belonging to different haplotypes were immunized with the recombinant virus. the antibody response to the circumsporozoite protein as well as to vaccinia virus varied among the strains, independently of each other. the anti-circumsporozoite protein titers were comparable to that obtained on immunization with irradiated sporozoites. spleen cells from h2d ...19911779992
[trends of tissue hypoxia following chemotherapy of acute malaria in mice].the effects of antimalarial treatment on the blood oxygen-transporting properties and on the tissue hypoxia were investigated in severe murine malaria, using mice infected with plasmodium berghei (nk65). five week old male ddy mice were inoculated intraperitoneally with 1 x 10(7) of p. berghei-infected red blood cells and treated with fansidar (20 mg/kg body weight sulfadoxine and 1 mg/kg body weight pyrimethamine orally) on day 5 after inoculation. parasitemia in these mice decreased rapidly on ...19911783800
malaria infection impairs glucuronidation and biliary excretion by the isolated perfused rat liver.1. the effect of the erythrocyte stage of malaria infection on hepatic glucuronidation, biliary excretion and oxidation processes was investigated using harmol, salbutamol, taurocholate and propranolol. livers from rats infected with the rodent malaria parasite p. berghei were isolated and perfused in a single-pass (harmol, taurocholate, propranolol) or recirculating (harmol, salbutamol) design. the degree of erythrocytic parasitaemia ranged from 16% to 63%. 2. the hepatic clearance (cl) of harm ...19911785204
susceptibility of multipotent haemopoietic stem cell deficient w/wv mice to plasmodium berghei-infection.the susceptibility of haemopoietic stem cell deficient w/wv mice to infection with plasmodium berghei was examined. the mean survival time of w/wv mice after the infection was shorter than that of the +/+ mice. splenomegaly, a characteristic pathological change of the host after infection with malaria parasites was not observed in w/wv mice. when haemopoietic activity of the infected mice was examined, a substantial increase in number of multipotent haemopoietic stem cells (cfu-s) and the commit ...19911787005
malaria sporozoites release circumsporozoite protein from their apical end and translocate it along their surface.plasmodium sporozoites, the causative agents of malaria, release circumsporozoite (cs) protein into medium when under conditions simulating those that the parasites encounter in the bloodstream of the vertebrate host. cs protein of the rodent parasite, plasmodium berghei, is released as the lower molecular weight form, pb44. this release is substratum- and antibody-independent. previous studies show that cs protein is released at the trailing, posterior end of motile sporozoites. video and elect ...19911787427
nucleotide status in erythrocytes of rats infected with plasmodium berghei. 19911789198
the mode of action of chloroquine. non-weak base properties of 4-aminoquinolines and antimalarial effects on strains of plasmodium.the mode of action of chloroquine was investigated by studying the properties of its 7-h derivatives, which retain the weak base properties of the quinolines but exhibit low antimalarial activity. using a specific probe [4-(1-amino-butylamino)quinoline] it has been shown that weak base properties are sufficient to induce concentration of the drug in the parasite's food vacuole. however, the chloroquine uptake we measured for the 7-h derivatives revealed a significantly low concentration of drug ...19911796865
the effect of defined media, additive nutrients and metabolites on the development of the sporogony cycle of plasmodium berghei in anopheles stephensi.anopheles stephensi mosquitoes were infected with plasmodium berghei by feeding on parasitaemic hamsters. after the infective blood meal they were separated into groups that were maintained on sugar solutions containing different additives. the numbers of oocysts developing in the various groups were then compared. when either casein, haemoglobin or foetal bovine serum was added to the sugar, the yield of oocysts was 1.6-2.1 times higher than that in controls fed only on sugar solutions. when ei ...19911796879
bromo-deoxyuridine is not incorporated into dna of malaria parasites. 19911801336
don't kill the parasite: control the disease.it is clear from both laboratory and clinical studies that the blood-stage malaria parasite does not itself directly cause most of the serious complications of the disease, with the possible exception of anaemia. for example, t cell- deprived mice with lethal infections survive longer and mice can be protected against early death by vaccines that appear not to affect parasitaemia. in certain cases antibodies to tnf have the same effect. clinically it has been known for over 50 years that childre ...19911820705
the need for live parasites for long-term immunity in malaria.all of the results of the various experiments support a role for living, proliferating parasites in the efficient induction of anti-parasitic as well as anti-disease (cm) immunity. non-proliferating parasites or material from disrupted parasites are poor or non-antigens in this respect. three possibilities as to why living parasites are important in immunity could be considered: 1. circulating parasites contain insufficient antigen to induce protective immunity, but sufficient antigen can be pro ...19911820706
variation in karyotype and gametocyte production during asexual multiplication of plasmodium berghei. 19911820712
antimalarial activity of crude extracts from brazilian plants studied in vivo in plasmodium berghei-infected mice and in vitro against plasmodium falciparum in culture.1. ninety-five crude extracts obtained with either organic solvents or water from 48 brazilian plants or parts of plants were evaluated experimentally as blood schizontocides. seventy-three extracts were obtained from 33 plants randomly collected using an empirical approach, and 22 from 15 "medicinal" plants. 2. the crude extracts were screened in vivo at up to 1.0 g/kg, po, for 4 days in mice infected with blood forms of plasmodium berghei and parasitemia was determined on the fifth day. 3. six ...19911823001
[synthesis and biological activities of 2,4-diamino-5-chloro-6-substituted quinazolines].title compounds were synthesized by condensation of 5-chloro-2,4,6-triaminoquinazoline (8) with various substituted benzaldehydes to produce the corresponding schiff bases, followed by reduction with nabh4, ii and iii were obtained by formylation or nitrosation of i respectively. primary screening for suppressive therapeutic effects against p. berghei in mice showed that eight of the twelve compounds produced 100% suppression when administered orally at dose of 20 mg/kg. the results against l121 ...19911823976
[effects of alpha-dimethylamino-cyclohexoxyl-dimethyl gallium on ultrastructure of erythrocytic stage of plasmodium berghei and p yoelii].the effects of alpha-dimethylamino-cyclohexoxyl-dimethyl gallium (dcdg), a new antimalarial drug developed in china, on the ultrastructure of murine malaria parasites in vivo was studied in comparison with those of chloroquine (cq) and artemisinin (art). all these 3 antimalarials were administered ig to mice at dosages of 1-3, 40-80, and 200-400 mg.kg-1 for dcdg, cq, and art respectively, based on a similar intensity of morphological changes in the parasites. blood samples were collected for ele ...19911824007
dietary modulation of malaria infection in rats.feeding of wistar albino rats on low protein and energy diet (4% protein) caused suppression of parasitaemia when infected with plasmodium berghei besides causing a depressed immune response. the refeeding of protein energy deficient rats on normal protein and energy diet (18% protein) for four weeks resulted in the normal course of parasitaemia after p. berghei infection. the present study was carried out to find the cause of suppression of malaria in protein energy deficient rats. the experime ...19911824358
histopathological studies in relation to protection induced by using mdp as an adjuvant in malaria.different immunomodulators were tried for their efficacy to protect against the lethal infection of plasmodium berghei in mice. since mdp was the most effective non-fca adjuvant imparting a significant degree of protection, histopathological studies were undertaken in mice protected by using this adjuvant in comparison with mice suffering from acute malaria. the malarious mice revealed abnormalities of the liver, spleen and kidney, whereas these abnormalities were minimal in the mdp-immunized mi ...19911824359
evaluation of ayush-64 for blood schizontocidal activity against rodent and simian malaria parasites.ayush-64, a new herbal antimalarial drug developed by the central council for ayurveda and siddha, was evaluated for direct parasiticidal action against p. berghei and p. yoelii nigeriensis in swiss mice and p. cynomolgi b and p. knowlesi in rhesus monkeys. no blood schizontocidal activity could be demonstrated against any of the four malaria parasites.19911824361
a cytochemical study of cerebrovascular lesions in mice infected with plasmodium berghei.mice with a plasmodium berghei infection exhibit morphological and cytochemical changes in the blood-brain barrier. changes in activity and localization of alkaline phosphatase and adenosine triphosphatase, enzymes with important functions in the maintenance of the blood-brain barrier, were observed. changes in activity and localization of those enzymes in and near the endothelial cells of the microvasculature, concomitant with an increase in pinocytotic activity, and formation of irregular cyto ...19911827497
glomerular filtration rate and plasma solutes in balb/c mice infected with plasmodium berghei.immune-complex glomerular nephritis (icgn) is known to develop during malarial infections, but little is known of its impact on renal function. a total of 24 male balb/c mice were infected with plasmodium berghei, and measurements of the glomerular filtration rate (gfr), parasitemia, and plasma solute concentrations were made on days 0, 7, 14, and 19 post-infection. identical observations were made on 24 uninfected controls. the gfr declined progressively in infected mice from a mean of 201 +/- ...19911832494
resistance to malaria in ankyrin and spectrin deficient mice.inbred mice carrying mutations in ankyrin and/or spectrin synthesis and assembly were studied for their ability to support the growth of the rodent malarias, plasmodium chabaudi adami and p. berghei, in vivo. mice carrying the nb/nb (normoblastosis) mutation which do not synthesize ankyrin and therefore also have a deficiency in membrane-bound spectrin, were refractory to p. chabaudi adami, which invades mature erythrocytes and to p. berghei, which invades reticulocytes. similarly, sph/sph mice ...19911832936
t cell receptor genes in a series of class i major histocompatibility complex-restricted cytotoxic t lymphocyte clones specific for a plasmodium berghei nonapeptide: implications for t cell allelic exclusion and antigen-specific repertoire.we report here the first extensive study of a t cell repertoire for a class i major histocompatibility complex (mhc)-restricted cytotoxic t lymphocyte (ctl) response. we have found that the t cell receptors (tcrs) carried by 28 h-2kd-restricted ctl clones specific for a single plasmodium berghei circumsporozoite nonapeptide are highly diverse in terms of v alpha, j alpha, and j beta segments and aminoacid composition of the junctional regions. however, despite this extensive diversity, a high pr ...19911836010
direct analysis of peptide binding to cell-associated mhc class i molecules.exogenously added synthetic peptides can mimic endogenously produced antigenic peptides recognized on target cells by mhc class i-restricted cytolytic t lymphocytes. while it is assumed that exogenous peptides associate with class i molecules on the target cell surface, direct binding of peptides to cell-associated class i molecules has been difficult to demonstrate. using a newly developed binding assay based on photoaffinity labeling, we have investigated the interaction of two antigenic pepti ...19911836776
the c-terminal domain of rna polymerase ii of the malaria parasite plasmodium berghei.the c-terminal domain (ctd) of rna polymerase ii (rnap) has an essential function in the regulation of transcription. the ctd of the human malaria parasite, plasmodium falciparum, differs dramatically from that of higher eukaryotes. to determine whether this is a general feature of malarial parasites, we have analysed the ctd of the distantly related rodent malaria parasite p.berghei. the ctds of the two parasites enzymes are very similar in amino acid composition and contain the basic structure ...19911840489
screening of the antimalarial activity of plants of the cucurbitaceae family.crude ethanolic extracts (cees) from two species of cucurbitaceae, cucurbita maxima and momordica charantia (commonly called "abóbora moranga" and "melão de são caetano", respectively) were assayed for antimalarial activity by the 4-d suppressive test. the cee of dry c. maxima seeds showed strong antimalarial activity following oral administration (250 and 500 mg/kg), reducing by 50% the levels of parasitemia in plasmodium berghei-infected mice. treatment of normal animals with 500 mg/kg of the ...19911841996
antimalarial chemotherapy with natural products and chemically defined molecules.in the present work we have described the in vivo antimalarial activity of six different plants. two of them (vernonia brasiliana and eupatorium squalidum) were tested in a randomic approach among 273 crude extracts from plants; four (acanthospermum australe, esenbeckia febrifuga, lisianthus speciosus and tachia guianensis) were selected after screening 22 crude extracts from different medicinal plants used in brazil against fever and/or malaria. we also studied chemically defined molecules and ...19911841997
comparative evaluation of blood schizontocidal activity of quinine and quinidine against drug resistant rodent malaria.blood schizontocidal activity of quinine and quinidine has been compared against sensitive as well as chloroquine/mefloquine/quinine resistant strains of plasmodium berghei and a multiple resistant strain of p. yoelii nigeriensis in swiss mice. evaluation of results on ed50/ed90 basis has shown distinct superiority of quinidine over quinine against sensitive as well as drug resistant strain of rodent malaria.19911842807
comparative and sequential histopathology of plasmodium chabaudi-infected balb/c mice.1. rodent experimental models have been useful to study severe malaria but few serial and controlled studies have been conducted. in the present investigation, we describe the histopathology of lethal and non-lethal rodent malaria induced by plasmodium berghei and p. chabaudi. p. berghei malaria shows a uniformly lethal course, while p. chabaudi malaria produces a non-lethal acute infection with recovery and periodical recrudescences. sequential histopathological changes were also characterized ...19911843871
[evaluation of the possible therapeutic effect of the plant rubim in plasmodium berghei experimental infection in mice]. 19911845014
purification and characterization of dihydroorotate dehydrogenase from the rodent malaria parasite plasmodium berghei.dihydroorotate dehydrogenase (dhodase) has been purified 400-fold from the rodent malaria parasite plasmodium berghei to apparent homogeneity by triton x-100 solubilization followed by anion-exchange, cibacron blue f3ga-agarose affinity, and gel filtration chromatography. the purified enzyme has a molecular mass of 52 +/- 2 kda on sodium dodecyl sulfate-polyacrylamide gel electrophoresis and of 55 +/- 6 kda by gel filtration chromatography, and it has a pi of 8.2. it is active in monomeric form, ...19911847078
cyclic amp level in red blood cells of plasmodium berghei-infected mastomys natalensis.the present report describes the changes in cyclic amp level which occur upon parasitization of red cells by plasmodium berghei. parasitized erythrocytes were separated from the non-parasitized population by percoll density-gradient centrifugation. an increase in the cyclic amp content of both non-parasitized and parasitized erythrocytes of infected animals compared with that of uninfected animals was observed. the patterns of physiological response to isoproterenol in normal, parasitized and no ...19911849086
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 ...19911855974
inhibition of the growth of plasmodium falciparum and plasmodium berghei by the dna polymerase inhibitor hpmpa.the acyclic adenosine analogue (s)-9-(3-hydroxy-2-phosphonylmethoxypropyl)adenine [hpmpa] belongs to a class of nucleoside analogues originally described as having potent activity against a broad spectrum of dna viruses. we examined the effects of this class of drugs on the growth of cultured plasmodium falciparum. strong inhibition was observed by hpmpa (id50 = 47 nm) at concentrations more than 1000-fold less than the cytotoxic dose for human cells. 3-deaza-hpmpa was even more strongly inhibit ...19911857384
immune response to plasmodium berghei sporozoite antigens. i. evaluation of murine t cell repertoire following immunization with irradiated sporozoites. 19911858962
pentoxifylline prevents murine cerebral malaria.pentoxifylline, a widely used methylxanthine, was tested for its capacity to prevent cerebral malaria (cm) in plasmodium berghei anka-infected cba/ca mice. nine of 12 control mice developed neurologic signs and died from cm approximately 2 weeks after infection. all 12 mice treated with daily intraperitoneal pentoxifylline (1 mg) for 10 days after infection did not develop cm. all surviving mice developed high parasitemia and severe anemia and died 2 weeks later without neurologic signs. in pent ...19911869848
recent studies on antimalarial efficacy of piperaquine and hydroxypiperaquine.piperaquine and hydroxypiperaquine seem to be successful candidates of antimalarial drugs in china. their antimalarial efficacy, experimental resistance, combination, mode of antimalarial action and clinical trials are described briefly.19911874015
dextran sulfate induced suppression of plasmodium berghei parasitaemia.effect of dextran sulfate (ds, mr 500,000) on parasitaemia in mice (balb/c) infected with erythrocytic stage of p. berghei was investigated. intraperitoneal injection of ds caused marked suppression of patent parasitaemia and also enhanced the survival time of the infected animals.19911874546
eosinophil-rich, granulomatous inflammatory response to plasmodium berghei hepatic schizonts in nonimmunized rats is age-related.inflammatory responses to plasmodium hepatic schizonts within the livers of non-immunized animals have long been assumed to be initiated only after the parasites have matured and begun to burst. however, recent reports of inflammatory responses around hepatic schizonts suggested a re-examination of this issue. we injected norway-brown rats of various ages intravenously with plasmodium berghei sporozoites and studied subsequent liver histopathology. we found that the ability of these rats to moun ...19911877714
multiple display of foreign peptides on a filamentous bacteriophage. peptides from plasmodium falciparum circumsporozoite protein as antigens.we describe here two systems for encoding foreign amino acid sequences in the exposed n-terminal segment of the major coat protein of bacteriophage fd. small peptides can be encoded directly; larger peptides are encoded in hybrid bacteriophage particles, in which the capsid is formed from a mixture of wild-type and modified coat proteins. in both cases, the peptides are present in multiple copies per phage particle. peptides that represent the circumsporozoite protein, the major surface antigen ...19911880799
[a titrographic method for determining the glycolysis flow rate with plasmodium berghei-infected red blood cells].a procedure is described for the elucidation of the glycolytic flux rate of red blood cells infected with the malarial parasite plasmodium berghei. it is based on the titration of the protons originating from the glycolytic lactate accumulation. compared with traditional methods of biochemical measurements of glucose consumption or accumulation of lactate the proposed procedure shows the following advantages: continuously measurement is possible; constancy of the ph-value during the measurement; ...19911888075
lack of h-2 restriction of the plasmodium falciparum (nanp) sequence as multiple antigen peptide.the major surface antigen of malaria sporozoites, the circumsporozoite protein, contains a region of tandem amino acid repeats, which in the case of the human malaria parasite plasmodium falciparum, consist of four amino acids asn-ala-asn-pro (nanp) repeated up to about 40 times. this repetitive sequence has been considered as the basis for the development of subunit vaccines against p. falciparum malaria. we and others had previously shown that synthetic and recombinant nanp peptides were immun ...19911889465
deet and permethrin as protectants against malaria-infected and uninfected anopheles stephensi mosquitoes.deet and permethrin were evaluated as protectants against plasmodium falciparum-infected, p. berghei-infected and uninfected anopheles stephensi mosquitoes. deet 50% effective dose (ed50) values were 3.2 micrograms/cm2 for p. falciparum-infected and 1.9 micrograms/cm2 for uninfected mosquitoes; permethrin values were 0.5 micrograms/cm2 and 0.6 micrograms/cm2, respectively. deet ed50 values were 2.3 micrograms/cm2 for p. berghei-infected and 1.3 micrograms/cm2 for uninfected mosquitoes; the perme ...19911895090
monoterpenic fragment analogues of aplasmomycin as potential antimalarial.seven analogues of monoterpenic fragment of aplasmomycin were synthesized as targeted antimalarial agents. the potency of the compound 6 was comparable with the sesquiterpene lactone artemisinin and the antibiotic aplasmomycin in vivo against plasmodium berghei yoelli.19911895301
the evolution of plasmodial stage-specific rrna genes is dominated by gene conversion.plasmodium species exhibit the unprecedented situation of distinct, stage-specific rrna sequences. we present an analysis of two pairs of sequences of the small rrna subunit (plasmodium falciparum and plasmodium berghei) and show that these genes do not evolve independently and that in fact their evolution is dominated by gene conversion. this analysis also shows that no extensive stage-specific sequences are conserved in the two species, thus rendering unlikely that the existence of stage-speci ...19911901094
plasmodium berghei: lactic acidosis and hypoglycaemia in a rodent model of severe malaria; effects of glucose, quinine, and dichloroacetate.fulminant malaria infections are characterised by hypoglycaemia and potentially lethal lactic acidosis. in young adult wistar rats (n = 26) infected with plasmodium berghei (anka strain), hyperparasitaemia (greater than 50%), anaemia (pcv 19.6 +/- 5.3%; mean +/- sd) hypoglycaemia (1.04 +/- 0.74 mmol/litre), hyperlactataemia (13.2 +/- 2.20 mmol/litre), hyperpyruvicaemia (0.51 +/- 0.12 mmol/litre) and metabolic acidosis (arterial ph 6.96 +/- 0.11) developed after approximately 14 days of infection ...19911901269
interferon-gamma enhances the effect of antimalarial chemotherapy in murine plasmodium vinckei malaria.most nonimmune patients with plasmodium falciparum infection are no longer cured by such standard antimalarial drugs as chloroquine. thus, alternative treatment regimens are necessary. a combination therapy was tested consisting of a subcurative dose of chloroquine and interferon-gamma (ifn-gamma) in balb/c mice with lethal plasmodium vinckei malaria. treatment with either agent alone prolonged median survival by 1-2 days compared with placebo-treated mice. however, a combination of 80 microgram ...19911902249
ifn-gamma inhibits development of plasmodium berghei exoerythrocytic stages in hepatocytes by an l-arginine-dependent effector mechanism.primary cultures of balb/cj hepatocytes treated with 10(3) u/ml rifn-gamma consistently inhibited intracellular plasmodium berghei liver schizont development by 50 to 70%. monomethyl-l-arginine (ngmmla), the competitive inhibitor of l-arginine as substrate for production of nitric oxides by hepatocytes, reversed the activity of ifn-gamma on these malaria-infected cells. reversal of ifn-gamma activity by ngmmla was dose dependent and was maximal at 0.5 mm ngmmla. depletion of l-arginine by additi ...19911903415
purification and characterization of dna polymerases from plasmodium berghei.dna polymerases from the malaria parasite plasmodium berghei were purified more than 50-fold. several distinct enzymatic activities were isolated that could be distinguished by the use of various specific dna polymerase inhibitors. in particular, subdivision into an aphidicolin-sensitive and an aphidicolin-resistant group was possible. further analysis allowed a better comparison with host dna polymerases and indicated that one aphidicolin-sensitive dna polymerase resembled dna polymerase alpha ...19911903844
ribosomal rna sequences of sarcocystis muris, theileria annulata and crypthecodinium cohnii reveal evolutionary relationships among apicomplexans, dinoflagellates, and ciliates.sarcocystis muris is a coccidium with a two-host life cycle involving the domestic cat and the mouse, mus musculus. s. muris and theileria annulata belong to the phylum apicomplexa, but the latter organism is a tick-borne protozoon in the subclass piroplasmea and causes tropical theileriosis in cattle. the small-subunit ribosomal rna (16s-like rrna) coding regions of these organisms as well as that of the free living dinoflagellate crypthecodinium cohnii were amplified using polymerase chain rea ...19911904987
detection of polymerase chain reaction-amplified malarial dna in infected blood and individual mosquitoes.chelex treatment of plasmodium falciparum and p. berghei infected tissues, in lieu of organic extraction, was followed directly by polymerase chain reaction amplification of primed circumsporozoite gene sequences. the amplified dna products were detected in stained gels and hybridization blots of extracts from individual infected mosquitoes and dissected mosquito tissues as well as small volumes of infected blood. parasite development, within the mosquito midgut and salivary gland, was also moni ...19911915745
antimalarial effect of cyclosporin-a on murine p. berghei and human p. falciparum.the effects of cyclosporin-a (csa) on the growth of plasmodia were investigated in an experimental murine model in vivo and on human malaria in vitro. mice were inoculated with plasmodium berghei and then treated with different doses of csa at the patent period. the development and course of this normally lethal parasitaemia in mice was affected by treatment with csa which is a known immunosuppressant. the drug showed complete protection at a dose of 20 mg/kg wt/day without any recrudescence. an ...19911915980
effect of plasmodium berghei infection and chloroquine on the hepatic drug metabolizing system of mice.the hepatic microsomal mixed-function oxidase (mfo) system was markedly impaired during plasmodium berghei infection in mice. cytochrome p-450 and other mono-oxygenases, viz. aniline hydroxylase, aminopyrine-n-demethylase and benzo(a)pyrene hydroxylase, were significantly decreased while microsomal heme showed a four-fold increase at peak parasitemia (greater than 50%). oral treatment with chloroquine (16 mg kg-1 body wt for 4 days) of p. berghei-infected mice cleared the parasitemia within 72 h ...19911917287
18s rrna sequences of leishmania enriettii promastigote and amastigote.dideoxy sequencing with reverse transcriptase and universal primers was used to obtain partial sequences of the 18s rrnas from the promastigote and amastigote life-cycle stages of l. enriettii. approximately 1400 nucleotides of sequence from the two stages were compared. unlike plasmodium berghei, in which 18s rrnas from the mosquito stage and the mammalian stage of the life cycle are only 96.5% similar, the amastigote and promastigote rrnas of l. enriettii are identical. in addition, a comparis ...19911917290
plasmodium berghei ookinete densities in three anopheline species.plasmodium berghei ookinete kinetics and densities were examined in the blood meals of 3 species of anopheles mosquitoes fed simultaneously from a gametocytemic mouse. simple techniques were developed for estimating relative and absolute ookinete densities within individual mosquito blood meals. the kinetics of ookinete formation were similar in all 3 species, with peak ookinete densities occurring from 12 to 24 hr postingestion. ookinete densities consistently were lower in anopheles stephensi ...19911919925
antimalarial activity and cytotoxicity of evodia fatraina stem bark extracts.stem bark extracts of evodia fatraina (rutaceae) were tested for antimalarial activity in vitro on plasmodium falciparum using an isotopic semi-microtest and in vivo on plasmodium berghei in mice. ethyl acetate extract showed moderate antimalarial activity in vitro (ic50 = 8.5 micrograms ml-1). however, ethanolic extract exhibited significant potency in vivo (65% suppression of parasitaemia). moreover, low toxicity against hela cells and l 929 fibroblasts was observed with ethanolic extract (ic5 ...19911921419
nucleotide sequence variation in the beta-tubulin genes from plasmodium berghei and plasmodium falciparum. 19911944421
transdermal artelinic acid: an effective treatment for plasmodium berghei-infected mice.artelinic acid, a derivative of the naturally occurring antimalarial artemisinin, has been incorporated into a gel suitable for transdermal administration. the formulation was tested for efficacy in plasmodium berghei-infected mice for both curative and prophylactic properties by application to their partially denuded backs, beginning on days 3 and 0, respectively, after injection of parasitized erythrocytes. in the curative experiments, rapid elimination of the parasitemia and 60-day survival o ...19911951870
[antimalarial activity of deoxoqinghaosu].compound 3 (deoxoqinghaosu) and compound 4 (deoxocarbaqinghaosu) were synthesized from arteannuic acid (2). primary exploration of their antimalarial effect against k173 strain of plasmodium berghei shows that compound 3 is somewhat more effective than the natural compound--qinghaosu. however, the carba-analogue compound 4 is almost ineffective. the enhanced activity of compound 3 is supposedly ascribed to its higher lipophilicity and, hence, higher affinity for plasmodial membrane. further stud ...19911957665
[preliminary studies on the diagnosis of plasmodium falciparum malaria by monoclonal antibody sandwich dot-immunogold silver staining assay].in this report, the blood samples from 30 falciparum malaria patients with parasitemia 0.015-0.58% and the blood samples from 30 healthy persons were examined by monoclonal antibody (mcab) sandwich dot-immunogold silver staining assay (dot-igssa). when the mcab 11g5, 13a2 and 13a1 were used for sandwich dot-igssa with mcab 14d9 labeled with colloidal gold respectively, the 0.0001% of parasitemia could be detected and the mcab 11g5, 13a1 and 14d9 labeled with colloidal gold could also be used to ...19911959167
circumsporozoite protein genes of malaria parasites (plasmodium spp.): evidence for positive selection on immunogenic regions.the circumsporozoite (cs) protein is a cell surface protein of the sporozoite, the stage of the life cycle of malaria parasites (plasmodium spp.) that infects the vertebrate host. analysis of dna sequences supports the hypothesis that in plasmodium falciparum, positive darwinian selection favors diversity in the t-cell epitopes (peptides presented to t cells by host mhc molecules) of the cs protein. in gene regions encoding t cell epitopes of p. falciparum, the rate of nonsynonymous nucleotide s ...19911706291
evaluation of the quantitative buffy coat (qbc) method to detect malaria-infected red blood cells.the conventional thin blood film method of detecting malaria is a long and tedious procedure, requiring significant technical expertise. in this study, we compared the quantitative buffy coat (qbc) capillary tube method, which requires only minimal technical training, to the thin blood film method, and found it to be not only more rapid but also more sensitive than the thin blood film method in the detection of parasitized red blood cells. we do not suggest that the qbc capillary method can repl ...19911711655
h-2kd-restricted antigenic peptides share a simple binding motif.we have defined structural features that are apparently important for the binding of four different, unrelated antigenic epitopes to the same major histocompatibility complex (mhc) class i molecule, h-2kd. the four epitopes are recognized in the form of synthetic peptides by cytotoxic t lymphocytes of the appropriate specificity. by analysis of the relative potency of truncated peptides, we demonstrated that for each of the four epitopes, optimal antigenic activity was present in a peptide of 9 ...19911714934
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 ...19911716146
prevention of murine cerebral malaria by a stable prostacyclin analog.iloprost, a synthetic prostacyclin analog, successfully prevents the development of cerebral malaria in mice. malaria antigen-induced tumor necrosis factor (tnf) production could be inhibited by iloprost in vitro and in vivo. northern analysis of tnf mrna revealed that malaria antigen-induced tnf expression was suppressed at the transcription level.19911716616
detection of different developmental stages of malaria parasites by non-radioactive dna in situ hybridization.a highly sensitive non-radioactive dna in situ hybridization procedure is described that enables detection and unequivocal identification of various developmental stages of human and rodent malaria parasites. using biotinylated species-specific dna probes, erythrocytic parasites can be specifically stained in blood smears. similarly exoerythrocytic stages can be visualized in cell culture and in sections of paraffin-embedded liver. in blood smears, the hybridization procedure provides a rapid de ...19911723723
the development of exo-erythrocytic schizonts of plasmodium berghei in vitro from gamma-irradiated and non-irradiated sporozoites: a study using confocal laser scanning microscopy.confocal scanning laser microscopy has been used to study the distribution of antigens expressed by the liver stages of plasmodium berghei in cultured hepatoma cells. the 3-dimensional images obtained of intact parasites clearly show complex patterns of antigen expression not apparent when using conventional ifat or immunoelectron microscopy. a liver-stage specific antigen (pbl 1) was shown to be confined to the parasitophorous vacuole; the vacuole has extensive diverticulae extending into the h ...19911658716
malarial dihydroorotate dehydrogenase mediates superoxide radical production.dihydroorotate dehydrogenase purified from mitochondria of plasmodium berghei, a rodent malaria parasite, mediates production of superoxide radical during oxidation of dihydroorotate to orotate. reduction of dichlorophenolindophenol or cytochrome c or nitroblue tetrazolium was significantly inhibited by superoxide dismutase or theonyltrifluoroacetone, a specific iron chelator of the enzyme. these results, together with the recent evidence of manganese-superoxide dismutase activity in malarial mi ...19911663740
plasmodium berghei: susceptibility and growth characteristics of hepatoma cells as hosts for malaria schizonts.three different human hepatoma cell lines (hep g2, london; hep g2, brussels; mahlavu) have been compared with respect to susceptibility for in vitro infection with plasmodium berghei sporozoites and subsequent development of mature schizonts and infectious merozoites. the results were very different, even with host cells derived from the same parent line. both hep g2 lines were able to function as host cells, but the mahlavu line was completely refractory. hep g2 (london) was even more susceptib ...19911665050
characteristics of multidrug resistance in plasmodium and leishmania: detection of p-glycoprotein-like components.multidrug-resistance (mdr) in neoplastic cells is frequently characterized by the overexpression of p-glycoprotein (pgp), a 170 kda transmembrane glycoprotein that binds multiple cytotoxic drugs as well as calcium channel antagonists. chloroquine resistance in plasmodium falciparum appears to be analogous to mdr in neoplastic cells, where the induction of resistance with one drug confers resistance to other structurally and functionally unrelated drugs. to test the hypothesis that chloroquine re ...19911678253
late treatment with anti-lfa-1 (cd11a) antibody prevents cerebral malaria in a mouse model.cba/ca mice injected with plasmodium berghei develop cerebral malaria (cm) characterized by ataxia and progressive paralysis leading to death 7-9 days after experimental infection. the development of cerebral symptoms is a function of the immune response in susceptible strains, and depends on cell-cell interactions involving t helper cells and mononuclear phagocytes. here we ask whether antibodies to cell adhesion receptors of the immune system can influence the development of cm in this mouse m ...19911679716
late administration of monoclonal antibody to leukocyte function-antigen 1 abrogates incipient murine cerebral malaria.we analyzed the role of adhesion molecules in the pathogenesis of experimental cerebral malaria (ecm), since tumor necrosis factor (tnf) plays a major role in this condition and has been shown to up-regulate in vitro expression of cell adhesion molecules (cam), particularly intercellular cam-1 (icam-1). we found increased expression of icam-1 on brain endothelial cells from mice with ecm. treatment with monoclonal antibodies (mab) directed against leukocyte function-antigen 1 (lfa-1, the ligand ...19911679717
asexual blood stages of malaria modulate gametocyte infectivity to the mosquito vector--possible implications for control strategies.in the rodent malarial parasite plasmodium berghei sexual parasites are produced in a single major wave with maximal numbers between day 7 and day 16. irrespective of their time of appearance during infection these sexual parasites are equally fertile in vitro. in contrast, in vivo infectivity to the mosquito is maximal at day 3-5 when gametocyte numbers are only 9% of the peak levels seen between days 7 and 16. up to 96% of natural potential infectivity of gametocytes for the mosquito is theref ...19911684037
coagulation disorders in experimentally induced acute mouse malaria.the development of coagulation disorders was studied in murine malaria. plasmodium vinckei was chosen following an initial experiment because onset and duration of parasitemia were more suitable for hemostasiological studies than in the short-lasting infection, caused by p. berghei. evaluation of the time courses of hematocrit, platelets, antithrombin (at) iii activity, factor v activity and parasitemia showed a significant decrease in platelets, hematocrit, factor v and at iii activity during t ...19911686145
analysis of immunity induced by the affinity-purified 21-kilodalton zygote-ookinete surface antigen of plasmodium berghei.by using affinity-purified ookinete surface antigen from the rodent malaria parasite plasmodium berghei, a transmission-blocking immunity was induced in mice. groups of mice were immunized via different routes, with total quantities of antigen ranging from 0.5 to 40 micrograms (with or without freund adjuvant). vaccination by the intramuscular route with 20 micrograms of antigen in the absence of adjuvant and boosted once with the same amount of protein induced a total transmission blockade. imm ...19911987051
plasmodium berghei: ionic regulation and the induction of gametogenesis.the role of ionic regulation in the induction of gametogenesis of plasmodium berghei at 20 degrees c was investigated. a potent inhibitor of na+/h+ exchange, amiloride, strongly inhibited exflagellation and subsequent ookinete formation induced by rpmi 1640 with 10% fetal calf serum at ph 8.0, whereas na+ or k+ channel inhibitors, h(+)-atpase inhibitors, and a protonophore had no significant effect. amiloride-treated 'activated' microgametocytes synthesized dna to levels consistent with the expe ...19911993463
antimalarial polyamine analogues.a series of novel tetraamines of the general formula rnh(ch2)xnh(ch2)ynh(ch2)xnhr was synthesized and examined for activity against growth of plasmodium falciparum in vitro. within the series, dibenzyl analogues (r = benzyl) were found to be the most effective growth inhibitors, with ic50 values of about 10(-6) m. further modifications of the tetraamine provided the optimum chain length for antimalarial activity of y = 7, x = 3. compound 8 (mdl 27,695) with the structure y = 7, x = 3, r = benzyl ...19911995879
the effect of malaria infection on antipyrine metabolite formation in the rat.we have shown that malaria infection can impair selectively the formation of antipyrine metabolites in the rat. during malaria, a significant increased urinary levels of unchanged antipyrine was observed (control: 1.7 +/- 0.4 vs test: 8.1 +/- 1.1% of dose, p less than 0.001). this was associated with significantly decreased excretion of 3-hydroxymethylantipyrine (control: 24.5 +/- 1.2 vs test: 21.4 +/- 0.7%, p less than 0.001) and 4-hydroxyantipyrine (control: 20.1 +/- 0.9 vs test: 15.5 +/- 1.3% ...19912009102
intraerythrocytic parasites and red cell deformability: plasmodium berghei and babesia microti.in the studies reported here, we examined the effects of two intraerythrocytic parasites (plasmodium berghei and babesia microti) on the deformability of their host red cells. red cell deformability was assessed by three criteria: 1) the prevalence of tank-treading (the tank-tread-like movement of the red cell membrane around its cytoplasmic contents), 2) elongation under fluid shear stress (the steady-state length: width ratio), and 3) the time required for the red cell to reduce its steady-sta ...19912018857
plasmodium berghei: quantitation of in vitro effects of antimalarial drugs on exoerythrocytic development by a ribosomal rna probe.a stage-specific ribosomal rna probe has been used to quantitate exoerythrocytic development of plasmodium berghei in primary cultures of mouse hepatocytes. parasite rrna could be detected as soon as 6 hr after sporozoite invasion and was increased during schizogony to a maximum at 48 hr, when mature schizonts were identified by microscopy. as few as 10 exoerythrocytic schizonts could be detected by filter blot hybridization, followed by autoradiography and liquid scintillation counting. by hybr ...19912026219
morphological characteristics of intracerebral arterioles in clinical (plasmodium falciparum) and experimental (plasmodium berghei) cerebral malaria.spastic constriction of intracerebral arterioles was identified in clinical (p. falciparum) and experimental (p. berghei) cerebral malaria. morphological criteria were used to characterize pathologically spastic constriction of arterioles. the significance of spastic constriction of intracerebral arterioles for microcirculatory disturbance in relation to development of cerebral malaria is discussed.19912027026
specific binding of antigenic peptides to cell-associated mhc class i molecules.t lymphocytes recognize antigen in the form of peptides that associate with specific alleles of class i or class ii major histocompatibility (mhc) molecules. by contrast with the clear mhc allele-specific binding of peptides to purified class ii molecules purified solubilized class i molecules either bind relatively poorly or show degenerate specificity. using photo-affinity labelling, we demonstrate here the specific interaction of peptides with cell-associated mhc class i molecules and show th ...19912027386
evaluation of merocyanine 540-sensitized photoirradiation as a method for purging malarially infected red cells from blood.the photosensitizing dye merocyanine 540 (mc 540) was evaluated as a means for purging malarially infected red cells from murine blood using the rodent malarial pathogens, plasmodium yoelii and plasmodium berghei, as models of human malaria. malarially infected red cells bound more mc 540 and were more sensitive to mc 540-sensitized photoirradiation than were noninfected erythroid cells. extracorporeal exposure of infected red cells to the dye and white light prevented the transmission of the di ...19912037797
[the effect of an extract from cochlospermum angolense ("burututu") on plasmodium berghei in the mouse malaria suppression test].often existing cross-resistance to structure analogous antimalarials causes the need to find new active compounds against malaria parasites. for this purpose the traditional medicine of tropical countries has proved to be a treasury. a root extract of cochlospermum angolense showed in vitro a remarkable activity against plasmodium berghei in the dna synthesis measurement with 3h-labelled hypoxanthine. this effect could be reproduced under in vivo conditions with the "4-day suppressive test" of r ...19912039095
the effect of malaria infection on paracetamol disposition in the rat.the effect of plasmodium berghei infection, a rodent malarial model, on the disposition of paracetamol (50 mg/kg, i.v.) was investigated in rats. malaria infection (mi) resulted in a significant decrease in clearance (control: 21.6 +/- 5.5 vs test: 11.8 +/- 2.9 ml/min/kg, p less than 0.005) with no change in volume of distribution and a significant prolongation of the elimination half-life (control: 30.7 +/- 6.3 vs 53.3 +/- 12.1 min, p less than 0.005) of paracetamol in malaria infected rats. th ...19912043159
stimulation by adjuvants of cell-mediated immune response in plasmodium berghei infected mice.immunological adjuvants (alum, liposomes and saponin) were utilized to stimulate cell-mediated immune response in plasmodium berghei infected balb/c mice. it was shown that malaria antigen mixed with adjuvant induced appreciably delayed type hypersensitivity and production of migration inhibition factor compared to antigen alone.19912055600
[in vitro cultivation of the exoerythrocytic stage of plasmodium berghei].this paper reports on an in vitro culture system for the exoerythrocytic (ee) stage of plasmodium berghei (p.b.) using embryonic lung cells. the system was first developed by our laboratory in china. the embryonic lung cells were isolated by trypsin digestion of a human embryonic lung obtained from a therapeutic abortion case and was designated as cell line elu 8801. anopheles stephensi mosquitoes were infected by biting p.b. anka strain infected kunming mice and after 18-21 days were dissected ...19912065449
[an experimental study of the effect of different biologically active substances on the susceptibility of mosquitoes to the causative agent of malaria. 1. insect development regulators].it has been shown on the model pair ae. aegypti-p. gallinaceum that dimilin, an inhibitor of insect chitin synthesis has practically no effect on female sensitivity to malaria agent. an analogue of the juvenile hormone juvemon at a concentration of 0.001-0.002 mg/l, causing death of 35% of insects, produces a 7-17% decrease in sporozoite index value. in concentration of 0.004-0.05 mg/l, there is a tendency towards an increase in the vector capacity of the survived female individuals. no differen ...19912067470
[the sensitivity of a plasmodium berghei strain resistant to artemisinin and other antimalarial preparations].the development of p. berghei resistance to artemisin has been studied. the narrs p. berghei strain which has 200 times lower sensitivity to artemisin was formed. different degree cross-resistance was established with quinine, chloroquine, dabequine, mefloquine; a high fansidar's efficacy in respect to narrs was observed.19912067477
[the computer processing of experimental research data on malaria. 1. the primary processing of the dynamic indices of malarial infection].universal computer software for primary statistical and graphic analysis of data on malaria dynamics in patients and in the experiment has been suggested. the analysis of the results of investigations on rodent malaria model in based on graded parasitemia assessment according to moshkovskiĭ [correction of mashkovsky].19912067496
evolutionary relationships of avian eimeria species among other apicomplexan protozoa: monophyly of the apicomplexa is supported.direct, reverse transcriptase-mediated, partial sequencing of the small-subunit (16s-like) ribosomal rna (srrna) of eimeria tenella and e. acervulina was performed. sequences were aligned by eye with six previously published, partial or complete srrna sequences of apicomplexan protists (plasmodium berghei, theileria annulata, cryptosporidium sp., toxoplasma gondii, sarcocystis muris, and s. gigantea). six eukaryotic protists (a slime mold, a yeast, two dinoflagellates, and two ciliates) acted as ...19912072862
protective immunization with invariant peptides of the plasmodium falciparum antigen msa2.three octapeptides from the n and c terminal c regions of the merozoite surface ag 2 (msa2) of plasmodium falciparum elicit anti-msa2 antibody when given as diphtheria toxoid conjugates. these antibodies also bind to the msa2 homolog from the rodent malaria plasmodium berghei. all mice vaccinated with these conjugates and challenged with an otherwise lethal inoculum of p. berghei showed substantial protection with most surviving. there was a inverse correlation between the development of the par ...19921727867
early hepatic stages of plasmodium berghei: release of circumsporozoite protein and host cellular inflammatory response.after injection of plasmodium berghei sporozoites into norway-brown rats, we were able to localize these sporozoites and the early hepatic trophozoites developing from them in histological sections of the liver stained with a sensitive immunogold-silver procedure. sporozoites invading hepatocytes released substantial quantities of circumsporozoite protein into the hepatocyte cytoplasm. this intrahepatic cytoplasmic distribution reached a maximal level at about 4 h post-sporozoite injection. as t ...19921729189
plasmodium berghei: in vivo generation and selection of karyotype mutants and non-gametocyte producer mutants.we previously reported that karyotype and gametocyte-producer mutants spontaneously arose during in vivo asexual multiplication of plasmodium berghei. here we studied the rate of selection of these mutants in vivo. gametocyte production and karyotype pattern were established at regular intervals during prolonged periods of asexual multiplication of clone 8417 of p. berghei. we found that karyotype mutants and mutants which do not produce gametocytes can replace the original high-producer parasit ...19921730264
effect of nifedipine treatment on oxidative metabolism of peritoneal macrophages and neutrophils of plasmodium berghei-infected mice.the oxidative metabolism of peritoneal macrophages (pm) and neutrophils from nifedipine (calcium channel blocker)-treated, plasmodium berghei (nk 65)-infected and normal infected swiss albino mice was studied. a significant fall in oxidative metabolism as evidenced by decreased chemiluminescence (cl) response (p less than 0.001) was recorded both in pm and neutrophils from nifedipine-treated mice compared to the control animals. when the oxidative metabolism of these phagocytes was studied after ...19921730270
interaction of antigenic peptides with mhc class i molecules on living cells studied by photoaffinity labeling.using a direct binding assay based on photoaffinity labeling, we have studied the interaction of antigenic peptides with murine mhc class i molecules on living cells. photoreactive derivatives were prepared by n-terminal amidation with iodo, 4-azido salicylic acid of the kd restricted plasmodium berghei circumsporozoite (p.b. cs) peptide 253-260 (yipsaeki) and the db-restricted adenovirus 5 early region 1a (ad5 e1a) peptide 234-243 (sgpsntppei). as assessed in functional competition experiments, ...19921737923
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