Publications

organization of the exoerythrocytic stage of the rodent malaria parasite plasmodium berghei. a cytochemical study.	with the osmium tetroxide-zinc iodide impregnation technique the visualization of the internal organization of the exoerythrocytic form of the rodent malaria parasite plasmodium berghei was improved. osmium impregnation leached the ground matrix of the parasite thereby displaying a system of intermediate-sized filaments. because microtubules are only present as part of the mitotic spindle and as remnants of the sporozoite cytoskeleton, the observed intermediate-sized filaments comprise most of t ...	1986	3537327
the course of plasmodium berghei infection in mice subjected to variable dosages of the parasite and the peak parasitaemia obtained accordingly.		1986	3537159
effect of inhibitors on glucose transport in malaria (plasmodium berghei) infected erythrocytes.		1986	3536772
plasmodium berghei: relative immunogenicity of infected reticulocytes and infected oxyphilic red blood cells.	hyperbleeding of mice 1 day before and 1 day after infection with plasmodium berghei resulted in a more aggravated infection. parasitemia rose significantly faster, but the mean survival time of these mice was not significantly different from control mice. at day 5 of infection, parasites were almost exclusively in reticulocytes in contrast to control infections in which parasites were found in oxyphilic erythrocytes at day 5 after infection. purified parasitized reticulocytes taken from hyperbl ...	1986	3536567
superoxide dismutase and catalase in the murine malaria, plasmodium berghei: content and subcellular distribution.	plasmodium berghei, a murine malaria, lacks endogenous superoxide dismutase (sod). instead it appears to take up and concentrate sod from its host cell, the erythrocyte. we now demonstrate that the adopted host enzyme is localized in granules which are probably lysosomes. in addition, isolated p. berghei parasites contain only low levels of catalase, probably as a result of contamination of the preparation with host cell material. thus, the cytosol of this organism appears to be deficient in enz ...	1986	3535681
antibody-dependent and -independent cytotoxic activity of spleen cells for plasmodium berghei from susceptible and resistant rats.	antibody-dependent cell cytotoxicity (adcc) mediated by spleen cells from 30- or 50-day old rats against 51cr-labelled rat erythrocytes parasitized by plasmodium berghei in the presence of anti-p. berghei antibody showed only slight age differences. however, in the absence of specific antibody, the total cell-mediated cytotoxicy (cmc) per spleen was four times higher in the spleen cells from 50-day-old rats compared with those from 30-day-old rats. cmc accounted for about 50% of total cytotoxic ...	1986	3533765
natural cytotoxicity for plasmodium berghei in vitro by spleen cells from susceptible and resistant rats.	the susceptibility of 30-day-old rats to plasmodium berghei infection has traditionally been ascribed to the higher levels of circulating blood reticulocytes for which p. berghei has a predilection. however, spleen cells soon develop natural cytotoxicity for p. berghei which may account, in part, for the increased natural resistance of older rats. spleen cells from normal 30- or 50-day-old rats were cultured overnight with erythrocytes parasitized by p. berghei and then injected into mf1 mice. s ...	1986	3533764
influence of malarial infection on the maternal-foetal relationship in pregnant mice.	pregnant mice infected on gestation day (gd) 6 with plasmodium berghei showed a more rapid rate of increase in parasitaemia than mice infected later in pregnancy or non-pregnant controls. all mice infected on gd 6 were dead by the 7th post-infection day. pregnant mice infected on gd 13, in contrast, had similar rates of parasitaemia and mortality as non-pregnant controls and 50% delivered normally, the foetuses were absorbed in 20% and 30% died before parturition. the pups born to mice infected ...	1986	3533019
effects of mycobacterium bovis bcg, bacterial lipopolysaccharide and hydrocortisone on the development of immunity to plasmodium berghei.		1986	3532283
[effect of vitamins d and e on the development of plasmodium berghei infection in mice].		1986	3531794
screening azadirachta indica and pisum sativum for possible antimalarial activities.	solvent-free extracts obtained from the leaves of azadirachta indica and pisum sativum were screened for antimalarial action using plasmodium berghei in mice. four days of oral dosing with 500 mg/kg and 125 mg/kg of the methanol extract of a. indica showed a parasite suppression which was statistically significant although all test animals died after 5 days, just 1 day longer than the untreated control group. a 50 mg/kg oral dose of the aqueous extract of p. sativum was found to have significant ...	1986	3531729
[parasitological and serological observations during pregnancy in mice infected with plasmodium berghei].		1986	3530149
[effect of maintaining a strain of plasmodium berghei anka on gametogenesis].		1986	3530148
[activity of 2 aminoglycoside antibiotics in plasmodium berghei infection in mus musculus].		1986	3530089
[probable loss of chloroquine resistance in plasmodium berghei inoculated in mus musculus previously irradiated with sublethal doses (300 r) of x-rays].		1986	3530088
[isoenzyme typing of strains of plasmodium berghei and plasmodium yoelii].		1986	3530087
[effect of dichroa febrifuga l. on chloroquinsensible and chloroquinresistant malaria parasites].		1986	3528514
carrier-linked primaquine in the chemotherapy of malaria.	the antimalarial effect of intravenously administered primaquine (pq) can be improved and its toxicity diminished by linking it to a macromolecular carrier protein. a thiol-containing primaquine derivative 8-[[4-(2-amino-3-mercaptopropionamido)-1-methylbutyl]amino]-6- methoxyquinoline was synthesized. this compound could readily be linked via a disulfide bond to a carrier protein containing (pyridyldithio)propionate groups. the derivative was coupled to serum albumin as well as to serum albumin ...	1986	3528491
protection of mice against plasmodium berghei infection by a tuftsin derivative.	in plasmodium berghei infections, the mortality rate and parasitaemias were significantly reduced and the mean survival time was considerably enhanced by pretreating the animals with a tuftsin derivative, thr-lys-pro-arg-nh-(ch2)2-nhcoc15h31. this effect of the modified tuftsin was further increased upon its incorporation in the liposome bilayer. these results indicate that tuftsin and its derivatives may prove useful in enhancing nonspecific host resistance against protozoan infections.	1986	3527754
plasmodium berghei: histology, immunocytochemistry, and ultrastructure of the placenta in rodent malaria.	the pathological changes associated with malarial infection in pregnancy were studied in rats and mice infected with plasmodium berghei at different stages of gestation. histopathological and ultrastructural studies of infected placentae near term in both species revealed disruption of architecture with gross thickening and necrosis of cells in the labyrinthine zone and fibrosis of the trilaminar trophoblast separating the maternal and fetal circulations. in the mouse, the extent of histopatholo ...	1986	3527738
catalase activity in red cell and liver of mice infected with plasmodium berghei.	hydrogen peroxide (h2o2) has been incriminated to have an oxidative killing malaria parasite. as p. berghei-infected mouse red cells generated h2o2 in vivo, this would result in the alteration of catalase status of the host. the present study was undertaken to determine catalase activity in red cells and liver of mice infected with p. berghei. the studies were performed in 17 samples of infected red cells as well as 20 samples of the normal red cells. results showed that the catalase activity in ...	1986	3526580
sialic acid analysis and tritium-labelling of sialoglycoproteins of mouse erythrocytes infected with plasmodium berghei.	schizont-infected red blood cells (si-rbc) from plasmodium berghei-infected mice contain between 2 and 10 times as much sialic acid as uninfected rbc from the same blood (99-550 micrograms/10(10) rbc versus 33-65 micrograms/10(10) rbc). total rbc samples from infected animals containing up to 63% ring- and trophozoite-infected cells had identical sialic acid contents to purified rbc samples (of less than 3% parasitaemia) from the same blood (52-64 micrograms/10(10) rbc). we conclude that rbc con ...	1986	3526260
protective immunity to malaria. studies with cloned lines of plasmodium chabaudi chabaudi and p. berghei in cba/ca mice. ii. the effectiveness and inter- or intra-species specificity of the passive transfer of immunity with serum.	serum was obtained from cba/ca mice infected, reinfected or superinfected with parasites taken one or two syringe passages from cryopreserved reference stabilates derived from cloned lines of the as or cb isolates of p.c. chabaudi. serum was also collected from mice superinfected with parasites derived from a cloned line of p. berghei ksp-11. when injected into normal syngeneic recipients subsequently challenged with homologous or heterologous parasites, these sera mediated some or all of the fo ...	1986	3523398
infectivity of plasmodium berghei sporozoites measured with a dna probe.	a 2.3 kb, 32p-labeled repetitive dna probe of plasmodium berghei was used to measure the amount of parasite dna in the liver of norway brown rats and mice infected with sporozoites. standard hybridization curves were obtained by probing different amounts (100 pg to 1 microgram) of p. berghei dna immobilized on nitrocellulose filters. host dna did not interfere with hybridization specificity and sensitivity. a 100-fold increase in hepatic parasite dna was detected between 25 h post-infection and ...	1986	3523238
immune t-cells and their lymphokines enhance phagocytosis of merozoites by macrophages.		1986	3522764
trypsin-sensitive plasmodia in the liver of post-infection rats and rhesus monkeys.	kupffer cells from the liver and erythrocytes from peripheral blood were collected at the post-patent period from albino rats infected earlier with plasmodium berghei and rhesus monkeys infected earlier with p. cynomolgi var. bastianelli or p. knowlesi. the cells were subinoculated into individual normal recipients. these recipients subsequently showed parasitaemia in their circulation. the parasites present in kupffer cell preparations were found to be sensitive to trypsin treatment, while thos ...	1986	3522381
plasmodium berghei: reduction of the mouse's specific lymphoproliferative response in relation to corticosterone and pregnancy.	spleen cells from mice immune to plasmodium berghei exhibited a significantly increased in vitro proliferative response to parasitized reticulocytes compared to spleen cells from normal mice. the specific response to malaria antigen was decreased in spleen cells from pregnant immune mice in contrast to the nonspecific response to the mitogen phytohemagglutinin. addition of mouse serum to spleen cell cultures of immune mice depressed both the phytohemagglutinin and the specific proliferative resp ...	1986	3522263
increased sensitivity in antigen detection during immunoblot analysis resulting from antigen enrichment via immunoprecipitation.	the sensitivity in antigen detection during immunoblot analysis is greatly increased if the antigen is first immunoprecipitated from the crude extract before electrophoresis and transfer to nitrocellulose. not only does the method allow detection of antigens which are minor components of crude mixtures or antigens which cannot be radiolabeled, but the method also resolves problems, such as high background, which are often associated with immunoprecipitation. also, by modifying the method, whethe ...	1986	3521383
the establishment of plasmodium berghei in mosquitoes of a refractory and a susceptible line of anopheles atroparvus.	the events between the ingestion of plasmodium berghei-infected mouse blood and the establishment of the ookinetes in the epithelium of the midgut in refractory (r) and susceptible (s) anopheles atroparvus are described. simultaneously fed, fully engorged female mosquitoes were randomly assigned to dissection at 22, 28, 32, 48 h and 10 days (controls) after the infective feed (post-infection: p.i.). serial transverse sections of 6 micron were cut. every 10th section was studied. the maturation o ...	1986	3521118
oxygen consumption in plasmodium berghei-infected murine red cells: a direct spectrophotometric assay in intact erythrocytes.	a spectrophotometric assay has been devised to measure oxygen consumption non-invasively in intact murine red cells parasitized by plasmodium berghei. the method uses oxyhemoglobin in the erythrocytes both as a source of oxygen and as an indicator of oxygen consumption. spectra of intact cells show broad peaks and sloping baselines due to light-scattering. in order to ascertain the number of varying components in the 370-450 nm range, the resolution of the spectra was enhanced using fourier tran ...	1986	3518808
synthesis and anthelmintic activity of 2,2'-disubstituted 5,5'-dibenzimidazolylsulfides and sulfones.	a number of substituted diphenylsulfides and sulfones (4-11) and 2,2'-disubstituted-5,5'-dibenzimidazolyl sulfides and sulphones (12-19) have been synthesized starting from 5-chloro-2-nitroacetanilide and (3) 4,4'-dichlorodiphenyl sulfone (9), respectively. among the compounds tested against ancylostoma ceylanicum in hamsters and hymenolepis nana in rats and mice, 14, 15, 18 and 19 removed 100% of the worms at an oral dose of 25 mg/kg x 1 to 250 mg/kg x 3. some of the compounds were tested for t ...	1986	3518728
[omega-aminoacyl compounds against malaria].	investigations on diphenylthioether derivatives led to compounds with a high antimalarial (p. berghei) activity. 58 new compounds were synthetisized in order to study structure-efficacy relationships. general formula: efficacy was optimal in compounds with r1 = no2. some of such compounds were at least half as effective as chloroquine and fully effective against drug resistant strains of p. berghei. but also other radicals proved to be suitable as long as s was not replaced by o. but two dipheny ...	1986	3516160
immunosuppression in murine malaria: role of activated macrophages.	the role of macrophages in immunosuppression which develops during plasmodium berghei infection in mice has been studied. the transfer of activated macrophages (or their extracts) from the infected mice with low parasitaemia (less than 10%) to uninfected mice enhanced their humoral response to sheep red blood cells (srbc) as indicated by the number of splenic igm and igg plaque-forming cells (pfc). in contrast, when macrophages obtained during higher parasitaemia (16%) were used, significant inh ...	1986	3516130
the ribosomal genes of plasmodium.		1986	3514510
2-acetylpyridine thiosemicarbazones. 12. derivatives of 3-acetylisoquinoline as potential antimalarial agents.	a series of 3-acetylisoquinoline thiosemicarbazones and their related thiosemicarbazides was prepared for evaluation as potential antimalarial agents. the former were synthesized by the reaction of 3-acetylisoquinoline with methyl hydrazinecarbodithioate to give methyl 3-[1-(3-isoquinolinyl)ethylidene]hydrazinecarbodithioate, iv. displacement of the s-methyl group of this intermediate by the requisite amines gave 3-acetylisoquinoline thiosemicarbazones, v. the corresponding thiosemicarbazides, i ...	1986	3513773
use of a two-sited monoclonal antibody assay to detect a heat-stable malarial antigen in the sera of mice infected with plasmodium yoelii.	antigens, circulating in the blood during malarial infections, have been implicated in immune protection, immunosuppression, and immune-complex formation. we used a monoclonal antibody (mab 7h8) to identify an antigen (ag-7h8) in the sera of mice infected with plasmodium yoelii. the major form of the antigen has a molecular weight of approximately 120,000 in p. yoelii, with minor components of 220,000; 65,000 to 75,000; and 45,000. ag-7h8 remains antigenic after boiling for 5 min. a two-sited as ...	1986	3512438
plasmodium berghei sporozoite invasion is blocked in vitro by sporozoite-immobilizing antibodies.	a monoclonal antibody directed against the circumsporozoite protein on the surface of plasmodium berghei sporozoites inhibited sporozoite motility in vitro. these immobilized sporozoites could adhere to but not invade target cultured cells. other sporozoite-immobilizing agents also inhibited sporozoite invasion into cultured cells and did not prevent sporozoite adherence. these results indicate that sporozoite invasiveness is associated with sporozoite motility. thus, the immobilizing effect of ...	1986	3512436
effect of macrophage activation on phagocyte-plasmodium interaction.	we investigated the effect of both immune and normal sera on the binding of free plasmodium berghei by resident and activated macrophages. resident macrophages bound plasmodia to a greater extent than did activated macrophages, regardless of treatment. resident macrophages bound free plasmodia, predominantly trophozoites, in the presence of normal serum by a mechanism inhibited by n-acetylglucosamine and n-acetylmannosamine. macrophages activated through treatment with propionibacterium acnes (" ...	1986	3512432
membrane fluidity changes in p. berghei-infected erythrocytes, investigated with a specific plasma membrane fluorescent probe.	trimethylamino-diphenylhexatriene (tma-dph), a novel hydrophobic fluorescent probe with relevant photophysical properties for fluorescence anisotropy measurements in phospholipidic membranes, specifically labels the plasma membranes of whole living-cells, unlike earlier commonly used probes such as 1,6-diphenyl-1,3,5-hexatriene (dph) and anthroyloxy fatty acids, which invade all hydrophobic regions of the cell. using tma-dph, it was shown that mouse malaria parasite plasmodium berghei induced a ...	1986	3511915
the effects of cortisone on immunity during chronic rodent malaria.	the temporal effects were studied of a single dose of hydrocortisone acetate on the development and expression of immune responses to plasmodium berghei in mice with chronic infections. cortisone administration prior to primary infection reduced malaria-specific secondary humoral and cellular responses, as well as the ability to survive parasite challenge. once protective humoral immunity was established after chemotherapy of primary infection, cortisone treatment did not disrupt its expression. ...	1986	3511746
plasmodium berghei malaria: effects of acute-phase serum and erythrocyte-bound immunoglobulins on erythrophagocytosis by rat peritoneal macrophages.	acute-phase serum (aps) collected from plasmodium berghei-infected rats inhibited phagocytosis of trypsinized rat erythrocytes and of erythrocytes from p. berghei-infected rats. macrophages (m phi) incubated with aps or heat-aggregated acute-phase serum (haaps) for 6 h, followed by 18 h incubation in serum-free medium, exhibited significantly higher levels of phagocytosis than m phi similarly cultured but with normal rat serum. when aps was present at the time of assay, it inhibited erythrophago ...	1986	3510164
effect of cyclosporin a and some derivatives in litomosoides carinii-infected mastomys natalensis.	litomosoides carinii-infected mastomys natalensis were treated 85 days post infection with cyclosporin a (cya) or 8 derivatives with different immunosuppressive capacities. cya (oral doses of 5 x 25 mg/kg, 5 x 50 mg/kg, 5 x 80 mg/kg on consecutive days) reduced parasitaemia levels in a dose dependent way, beginning 3 weeks after first drug administration. using 5 x 50 and 5 x 80 mg/kg animals were free from circulating microfilariae on the day of necropsy (day 56). derivatives were administered ...	1987	3437108
malaria in beta-thalassemic mice and the effects of the transgenic human beta-globin gene and splenectomy.	to investigate the protective effects of beta-thalassemia against malaria, rodent malaria parasites were studied in c57bl/6j mice with beta-thalassemia, in mice in which the thalassemia had been transgenically corrected with the human beta a-globin gene, and in hematologically normal mice. in thalassemic mice, plasmodium chabaudi adami infection was inhibited and peak parasitemia was variably delayed. in transgenically corrected mice, infection proceeded as in normal mice. plasmodium berghei inf ...	1988	3335824
concerning steric effects in antimalarial agents.	acridine, the parent nucleus of atabrine, is much more toxic than its 4,5-dimethyl derivative. the 4,5-dimethyl derivative of atabrine was therefore synthesized in the hope of producing a better-tolerated drug. the analogue was considerably more toxic than atabrine.	1987	3334542
effects of levamisole on experimental infections by plasmodium berghei in mice.		1987	3333878
sensitivity of malaria parasites to artemether (qinghaosu derivative) depends on host cell age.		1987	3332510
the complete development in vitro of the vertebrate phase of the mammalian malarial parasite plasmodium berghei.	all three 'vertebrate' stages of the rodent malarial parasite plasmodium berghei berghei were grown in vitro in the absence of the vertebrate host. the parasite was introduced into culture from infected mosquitoes and 2 in vitro culture methods were used sequentially to complete the 'vertebrate' phases of development in hepatoma and erythrocyte host cells. the resultant blood infection produced mature schizonts and male and female gametocytes. the protocol, which is now being extended to the hum ...	1987	3332508
some hemoglobin modifications in malaria.		1987	3332072
the chemotherapy of rodent malaria. xlii. halofantrine and halofantrine resistance.	as a blood schizontocide, halofantrine is about three times as active against a drug-sensitive line of plasmodium berghei (n strain) as chloroquine, but it lacks any causal prophylactic effect. this activity is retained against parasites highly resistant to primaquine, cycloguanil, pyrimethamine, sulphaphenazole and menoctone. a marked resistance to halofantrine is shown by parasites resistant to mefloquine, quinine, chloroquine and amodiaquine, although the moderately chloroquine-resistant 'ns ...	1987	3331253
[antimalarial activity of various isoquinoline alkaloids in the mouse].		1987	3331070
[experimental study on the possibility of prevention of post-transfusional malaria, by using gentian violet].		1987	3330860
antimalarial activity of 4,4'-bis-dimethylaminodiphenyl sulfone.		1987	3330051
[studies on the reappearance of gametocytes of plasmodium berghei].		1987	3329994
[therapeutic effects of 13 combinations of antimalarials against plasmodium berghei "ns" strain].		1987	3329993
[effects of 13 compounds on the activity of globinase and amounts of free amino-acids in plasmodium berghei].		1987	3329808
[synthesis of trifluoromethyl amodiaquine analogs and antimalarial activity].		1987	3329806
[acid phosphatase activity of circulating leukocytes in mice in experimental malaria].		1987	3329288
antimalarial activity of bisdesethylchloroquine against p. falciparum and p. berghei berghei.		1987	3328569
[determination of the activity of globinase from plasmodium berghei by radiometry with mouse [3h]globin as a substrate].		1987	3328465
the effect of combinations of qinghaosu (artemisinin) with standard antimalarial drugs in the suppressive treatment of malaria in mice.	artemisinin is a novel antimalarial drug isolated in china from the wormwood plant artemisia annua l. studies with rodent malaria were carried out to detect antagonism and synergism with a variety of antimalarial drugs. isobolograms of drug interaction were plotted at the ed90 level. with a normally susceptible strain of plasmodium berghei, marked potentiative synergism was found with mefloquine, tetracycline and spiramycin. there was some synergism also with primaquine. combinations of artemisi ...	1987	3328341
prevention of murine cerebral malaria by low-dose cyclosporin a.	the effects of cyclosporin a (csa) were investigated in an experimental model of cerebral malaria. in this model, plasmodium berghei anka-infected cba/ca mice develop a clinically and histologically characterized neurological syndrome which is considered to be the result of immunopathological reactions mediated by l3t4+ t cells. it was shown that csa displayed a strong protective effect on neurological complications when given at a dose 1 mg/kg/day for 5 consecutive days (days 4-8), which had no ...	1987	3327806
effect of zinc diet on xanthine oxidase activity of liver of mice infected with plasmodium berghei.		1987	3326753
studies on the comparative gametocytaemia of p. berghei (nk 65) in male and female mastomys natalensis.		1987	3326752
antiparasitic agents. part 7--antimalarial activity of alkyl 5(6)-(4-aminophenyl) sulphonobenzimidazole-2-carbamates.		1987	3326751
plasmodium berghei malaria: effect of acute phase serum on immunity generated in rats by infection and by vaccination.	acute phase serum (aps) given at the time of challenge with plasmodium berghei inhibited the generation to immunity to the infecting plasmodia. administered with a single dose of vaccine, it inhibited induction of immunity by the vaccine. three weekly doses, the last given two weeks before infection, induced immunity. administration of vaccine simultaneously with infection neither aggravated nor ameliorated the infection. these results indicate that the effect of administration of aps on immunit ...	1987	3325980
[biochemical principles of the action of drugs in malaria].		1987	3325791
polyclonal b-cell activation and autoantibody formation during the course of mosquito-transmitted plasmodium berghei infection in mice.	the time course of polyclonal b cell activation, as measured by titers of antibodies to dnp, fitc, and haemocyanin, as well as the time course of autoantibody formation, was followed in mice infected with plasmodium berghei via anopheles stephensi. igm class antibodies to dnp, fitc, and haemocyanin appeared earlier than igg class antibodies and persisted until death. only igm class anti-dnp peaked, the others remained high until death. although igm class autoantibodies also appeared earlier than ...	1987	3324285
purification of a plasmodium berghei neutral endopeptidase and its localization in merozoite.	a plasmodium berghei neutral endopeptidase specific for the fluorogenic substrates valyl-leucyl-glycyl-arginyl/lysyl-aminoethyl-carbazole was purified by fast protein liquid chromatography. the enzyme was a mr 68,000 polypeptide. immunization of mice with the purified enzyme gave a specific antiserum, as demonstrated by immunoblotting. immunofluorescence with this antiserum showed a strong labelling of p. berghei merozoites in mature segmented schizonts and of merozoites released from schizont-i ...	1987	3323905
long-term in vitro cultivation of plasmodium berghei.		1987	3323090
effect of variation in temperature on development of plasmodium berghei (nk 65 strain) in anopheles stephensi.	effect of temperature on the sporogonic cycle of plasmodium berghei (nk 65) has been studied in vector anopheles stephensi. to determine the optimum temperature for development of parasite, fed mosquitoes were kept at 16 +/- 1 degree c, 19 +/- 1 degree c and 26 +/- 1 degree c temperature. the temperature 19 +/- 1 degree c was found to be optimum for normal development of parasite within the vector. sporulated oocysts were observed on the 10th day post feed and salivary glands were loaded with th ...	1987	3322990
concomitant infections of anopheles stephensi with plasmodium berghei and serratia marcescens: additive detrimental effects.	the mortality rate of anopheles stephensi increased after infection with plasmodium berghei and correlated negatively with temperature. development of oocysts is inhibited at temperatures above 21 degrees c. we tested the hypothesis that microorganisms were involved in killing the mosquitoes. in fact we were able to demonstrate that in our a. stephensi colony great numbers of serratia marcescens could be found in the midgut of the insects. the highest value was 2.3 x 10(7) cfu/ml. other bacteria ...	1987	3321762
glutathione and peroxide metabolism in malaria-parasitized erythrocytes.	the glutathione metabolism of plasmodium falciparum, p. vinckei and p. berghei has been investigated. human erythrocytes with low glutathione reductase and synthetase activity are still capable of harbouring p. falciparum. both enzymes have been demonstrated in plasmodium spp. moreover, evidence is given for a selenium-independent glutathione peroxidase in malaria parasites.	1987	3321043
rapid nucleotide sequence analysis of the small subunit ribosomal rna of toxoplasma gondii: evolutionary implications for the apicomplexa.	a method for obtaining a large proportion of the nucleotide sequence of the small subunit ribosomal rna (srrna) was applied to the obligate intracellular protozoon toxoplasma gondii. the method uses reverse transcription of as little as 8 micrograms of total cellular rna. this fast, efficient method has numerous advantages over traditional gene cloning methods when nucleotide sequences are required for evolutionary studies. a phylogenetic analysis of the srrna sequence data showed that t. gondii ...	1987	3320746
cellular response against exoerythrocytic forms of plasmodium berghei in rats.	rats were infected with plasmodium berghei sporozoites, and 47, 51, and 57 hr later exoerythrocytic parasites were examined by electron microscopy. at 47 hr, approximately 30% of nearly mature exoerythrocytic parasites were degenerating and were surrounded by a cellular infiltrate of kupffer cells, monocytes, monocyte-derived macrophages, and neutrophils. neutrophils appeared to be actively ingesting electron-dense fuzzy parasite material which was normally present in the parasitophorous vacuole ...	1987	3318519
synthetic peptide vaccine confers protection against murine malaria.	a synthetic peptide, (dppppnpn)2d, representing a subunit of the repeat domain of the plasmodium berghei circumsporozoite protein, was conjugated to tetanus toxoid using bisdiazobenzidine. immunization of mice and rats with the conjugate induced high serum titers of antibodies to the parasite, and most of the animals were completely protected from malaria infection when challenged with sporozoites.	1987	3316473
characterization of lipidous antigens derived from erythrocytes infected with plasmodium berghei.	a lipid extract obtained from reticulocyte membranes of plasmodium berghei-infected rats showed antigenic activity against sera from convalescent or immune rats. following chromatography on silicic acid column, 85% of the activity was recovered from the column with chloroform:methanol (1:3, vol/vol). the active fraction was further resolved by thin layer chromatography (tlc) into four lipid components, two sugar-containing components and two phosphorous-containing components, but neither the ind ...	1987	3316119
plasmodium berghei, p. chabaudi, and p. falciparum: similarities in phosphoproteins and protein kinase activities and their stage specific expression.	phosphoproteins from plasmodium berghei, p. chabaudi, and p. falciparum are compared. a major phosphoprotein of 46 kda is found in all three species. peptide mapping indicates that this protein is indeed the same in all three cases and is phosphorylated at similar sites in all three species. monoclonal antibodies were raised against three other p. berghei phosphoproteins. all three monoclonal antibodies recognize both p. berghei and p. chabaudi proteins. only one of the monoclonal antibodies cro ...	1987	3315732
oxidant stress in malaria as probed by stable nitroxide radicals in erythrocytes infected with plasmodium berghei. the effects of primaquine and chloroquine.	erythrocytes from normal mice and mice infected with the malarial parasite plasmodium berghei reduce the water-soluble spin probes 2,2,6,6-tetramethylpiperidine-4-hydroxy-n-oxyl (tempol), 2,2,6,6-tetramethylpiperidine-n-oxyl (tempo) and 2,2,6,6-tetramethylpiperidine-4-keto-n-oxyl (tempone) at similar rates under both air and n2 atmospheres. the esr signal of the lipid-soluble spin probe 5-doxyl-stearate is stable on incorporation into erythrocytes from normal mice. in contrast, parasitized red c ...	1987	3315005
the activity of drug combinations against established infections of rodent malaria.	in the experiments reported here treatment (with a single dose or daily for 4 days) was delayed until 3 days after inoculation. various combinations of m&b 35,769, 2:4-diamino-5-[3(4-4'-chlorophenylphenoxy)propyl-1-oxy]-6-methylpy rimidine hcl, plus sulphadoxine, and of m&b 35,769 plus dapsone, were examined and it was concluded that no universally ideal ratio of constituents in a combination is possible because the optimum ratio depends upon the activity of the constituents on their own and the ...	1987	3313204
antimalarial agents. iii. mechanism of action of artesunate against plasmodium berghei infection.		1987	3311413
antimalarial and anticoccidial activity of 3-aryl-7-chloro-3,4-dihydroacridine-1,9-(2h,10h)-diones. 1-imines, 1-amines, 1-oximes, 1-hydrazones and related compounds.	out of more than 130 synthesized derivatives of floxacrine and of 10-deoxyfloxacrine, such as 3-(4-trifluoromethyl-phenyl) or 3-(4-chlorophenyl)-7-chloro-10-hydroxy- or -10-deoxy-3,4-dihydroacridine- 1,9(2h,10h)-dione 1-imines and 1-hydrazones, more than 45 showed an activity against asexual stages of plasmodium berghei in the mouse which was comparable with or superior to that of floxacrine. more than 25 derivatives of the 3-(4-chlorophenyl)-floxacrine series and 3-(4-chlorophenyl)-10-deoxy-flo ...	1987	3311052
a radioimmunoassay for the diagnosis of malaria.	a newly developed radioimmunoassay for the diagnosis of malaria has been tested in south africa. the radioimmunoassay is an antibody binding-inhibition assay, based on a monoclonal antibody (d5) cross-reacting with plasmodium berghei and p. residual binding activity was tested on antigen-coated microtiter plates. a sample was considered positive if it inhibited binding of the antibodies to an extent exceeding that of the microscopically negative blood samples. blood was collected on 3 separate o ...	1987	3310678
plasmodium berghei: long lasting immunity induced by a permanent attenuated mutant.	a long-lasting immunity against challenge with highly virulent plasmodium berghei (nk65) was observed in balb/c mice immunized with a permanently attenuated parasite (xat), a derivative (xat) of the nk65 strain. mice infected with living xat parasites showed an extremely low self-resolving type of parasitaemia followed by a strong immunity against a challenge with the lethal parent nk65 strain. this immunity lasted for nearly one year. cross immunity was also observed in the immune mice after ch ...	1987	3310467
the role of thymocytes and igg antibody in protection against malaria in nude rats.	congenitally athymic nude (rnu/rnu) rats developed a high level of parasitemia and died with severe anemia after infection with plasmodium berghei, while heterozygous littermates (rnu/+) showed a self-limiting infection and resisted further challenge. transfer of normal thymocytes failed to protect rnu/rnu rats from the subsequent infection. transfer of immune igg fraction conferred resistance to malaria on rnu/+ but not on rnu/rnu rats. when both normal thymocyts and immune igg were administere ...	1987	3310466
plasmodium berghei: a study of globinolytic enzyme in erythrocytic parasite.	an acid protease of plasmodium berghei (nk 65) was extracted from parasite lysate and purified by means of gel filtration followed by deae-sephadex column chromatography. the enzyme showed especially high activity to degrade hemoglobin. the ph optimum of the purified enzyme was 3.2, km value was 0.012 mm. molecular weight of the enzyme was estimated by gel chromatography as being 18,000-20,000. the enzyme activity was specifically inhibited by pepstatin, one of the peptide aldehyde protease inhi ...	1987	3310465
modulator effect of toxoplasma lysate antigen in mice experimentally infected with plasmodium berghei.	normal mice were pretreated twice at an interval of 2 weeks with an emulsion of tla (toxoplasma lysate antigen), pla (plasmodium lysate antigen) or both in lmo (light mineral oil) or with a combination of the emulsion and obioactin or tp-lks (toxoplasma lymphokines) as an immunopotentiator. they were then given obioactin or tp-lks 3 and 25 days after the first treatment and were further given parasitized erythrocytes with 1 x 10(2)-10(4) p. berghei 2 weeks after the second treatment. thirty (3/1 ...	1987	3310463
an alternative approach to malaria vaccine with a permanent attenuated mutant from a high virulence plasmodium berghei strain.	an alternative approach to malaria vaccine with the use of plasmodium berghei nk65xat (xat) is reviewed. xat is a permanent low virulence strain derived from high virulence p. berghei nk65 (nk65) by irradiation. although one organism of parent nk65 could kill one mouse, as many as 10(7) xat parasites caused modest self limiting parasitaemia in immuno-competent mice. in the mice recovered from xat infection, long lasting immunity to challenge not only by parent nk65, but also by anka so far as di ...	1987	3310458
superoxide dismutase and catalase activities in spleen of mice infected with plasmodium berghei.		1987	3310256
the infectivity and purification of cultured plasmodium berghei ookinetes.	plasmodium berghei ookinetes were cultured from hamster blood as described previously (kurtti and munderloh, 1986). an average of 7.3 x 10(6) ookinetes was harvested from each ml of blood. ookinetes were purified by centrifugation on first a 40% and then a 36% percoll gradient. the final preparation comprised 32.8% of the ookinetes initially obtained, and contained 3.3 other parasite stages or blood cells per ookinete. unpurified and purified ookinetes were resuspended in hamster blood and fed t ...	1987	3309240
platelet reactions in acute plasmodium berghei infection in swiss albino mice.	swiss albino mice were infected by the intraperitoneal route with p. berghei berghei malaria parasite, and platelets, white cell counts and some coagulation parameters were monitored in order to find out whether changes reported in man also occurred in the mice. parasitaemia developed form the 2nd post-infection day and reached significant levels by the 4th-6th day. reduced circulating platelets which reached severe thrombocytopenic levels were observed. parallel with the increasing degree of pa ...	1987	3308658
malaria specific human t cell clones: crossreactivity with various plasmodia species.	peripheral blood mononuclear cells (pbmc) from donors with or without previous exposure to malaria in vivo were cultivated for 4 to 7 days in the presence of different malaria antigen (m.ag) preparations: plasmodium falciparum (p.f.ag), p. berghei (p.b.ag) and p. gallinaceum (p.g.ag). all preparations induced a proliferative response in pbmc from donors with or without previous exposure to malaria. pbmc from both groups of donors were then primed with each of the three m.ag and cloned in presenc ...	1987	3308225
decreased hepatic elimination of pyrimethamine during malaria infection. studies in the isolated perfused rat liver.	the elimination of the antimalarial drug pyrimethamine was studied in isolated liver preparations from young rats (80-100 g) infected with merozoites of plasmodium berghei two weeks earlier. perfusate half-life of pyrimethamine was increased in livers from m.i. rats (t1/2 beta control group = 56 +/- 11 min vs m.i. group = 101 +/- 12, p less than 0.01), reflecting a decrease in hepatic clearance (3.6 +/- 1.1 ml/min vs 1.9 +/- 0.5 ml/min, p less than 0.01). there was no significant difference in v ...	1987	3307789
the chemotherapy of rodent malaria, xl. the action of artemisinin and related sesquiterpenes.	artemisinin (qinghaosu), a poorly soluble sesquiterpene lactone derived from the plant artemisia annua linn., and a number of more soluble, semi-synthetic derivatives are rapidly-acting blood schizontocides against plasmodium berghei and p. yoelii nigeriensis. an oily suspension of artemisinin given s.c. is more effective than aqueous suspensions. the activity is retained against lines resistant to primaquine, cycloguanil, pyrimethamine, sulphonamides, mefloquine and menoctone, but a highly chlo ...	1986	3307655
tumor necrosis factor (cachectin) as an essential mediator in murine cerebral malaria.	tumor necrosis factor, or cachectin (tnf-alpha), a protein with a wide range of biological activities, is produced mainly by macrophages and may be important in inflammatory processes. the role of tnf-alpha in the pathogenesis of cerebral malaria was investigated in a murine model. most cba mice infected with plasmodium berghei anka die between days 6 and 14 with acute neurological manifestations unrelated to the level of parasitemia, whereas mice of some other strains have malaria of the same s ...	1987	3306918
[experimental study on the effect of plasmodia on the erythroid colony forming unit (cfu-e)].		1987	3304701
pathophysiology of hypoxia in mice infected with plasmodium berghei.	pathophysiological significance of hypoxia in malarial infection was investigated in mice infected with plasmodium berghei nk65. intraperitoneal inoculation of mice with 1 x 10(7) parasitized red blood cells resulted in death of the hosts 6-7 days later. anaemia of infected animals developed on day 4 after inoculation and oxygen affinity of whole blood, measured as p50 act ph, increased simultaneously. this change may be a physiological adaptive response to a reduction in oxygen delivery to the ...	1987	3303017
endoperoxides as potential antimalarial agents.	a number of mono- and bicyclic endoperoxides were prepared and tested for antimalarial activity in search of a simplified analogue of the 5-oxygen-substituted 1,2,4-trioxane ring structure of the naturally occurring antimalarial qinghaosu. the compounds were assayed in an in vitro system for antimalarial activity against chloroquine-susceptible and chloroquine-resistant strains of p. falciparum. the most active compound in this assay was 2-[((butyloxy)-carbonyl)oxy]-1,1,10-trimethyl-6,9-epidioxy ...	1987	3302259
plasmodium berghei and plasmodium chabaudi: a neutral endopeptidase in parasite extracts and plasma of infected animals.	by using a sensitive fluorometric method with val-leu-gly-arg-3-amino-9-ethylcarbazole (vlgr-aec) as a substrate, two endopeptidase activities were identified in two fractions of sephacryl s-200 gel filtration from soluble p. berghei and p. chabaudi extracts. controls with normal mouse erythrocytes, with leukocytes, and with reticulocyte enriched blood and different washing procedures during the preparation of soluble p. berghei extracts showed that the mw greater than 200 kda fraction was a con ...	1987	3301390
the relationship of phosphorylation of membrane proteins with the osmotic fragility and filterability of plasmodium berghei-infected mouse erythrocytes.	membrane from plasmodium berghei-infected mouse erythrocytes showed a pattern of protein phosphorylation which was substantially altered from the normal pattern, with an increase in the phosphorylation of the protein with an apparent molecular weight of 43,000 (m 43), which increased from undetectable in uninfected cells to a maximum in the mature trophozoite stage. phosphorylation levels of this and other minor bands were strongly correlated with osmotic fragility and filterability. the level o ...	1987	3300785
plants as sources of antimalarial drugs, part 4: activity of brucea javanica fruits against chloroquine-resistant plasmodium falciparum in vitro and against plasmodium berghei in vivo.	extracts of brucea javanica fruit have been prepared and monitored for their in vitro and in vivo antiplasmodial activities. the antimalarial activity of the fruit was found to be attributable to its quassinoid constituents. nine of the quassinoids possessed in vitro ic50 values between 0.046-0.0008 microgram/ml against the chloroquine resistant plasmodium falciparum strain (kl) tested. the two quassinoid glycosides tested were considerably less active in vitro than the aglycones. four quassinoi ...	1987	3298551