| rat malarial glomerulonephritis. an experimental model of post-infectious glomerular injury. | this paper describes the immunopathologic findings in acute malaria-associated glomerulonephritis in the rat. young sprague-dawley rats were infected with plasmodium berghei berghei. the subsequent parasitemia and elevation of circulating clq-reactive immune complexes were transient while the appearance of anti-plasmodial antibody in the serum was persistent. sequential examination of renal tissue and urine revealed the following glomerular alterations: (a) granular, predominantly mesangial depo ... | 1981 | 6117979 |
| inhibition of idiotype--anti-idiotype interaction for detection of a parasite antigen: a new immunoassay. | described in this report is an immunoradiometric assay of general applicability that is based on a new principle: the inhibition of the interaction between monoclonal antibodies by an antigen. the advantages of this assay are that it measures concentrations of single epitopes, purified antigen is not required, and the reagents can be obtained in unlimited amounts and are homogeneous. its features are particularly attractive when the antigen has not been purified and is a minor component of a com ... | 1982 | 6122269 |
| retention of plasmodium berghei sporozoites within perfused mouse livers. | a mouse liver perfusion model was adapted to evaluate the efficiency of the liver in retaining plasmodium berghei sporozoites. specific numbers of sporozoites were perfused into each liver via a portal vein cannula. the numbers of sporozoites in the perfusate effluent were counted and the percent sporozoite retention calculated. over 95% of sporozoites suspended in medium with plasma were retained in a normal liver following a single passage. sporozoites were seen in sinusoids of perfused livers ... | 1982 | 6122362 |
| production of monoclonal antibodies by hybridomas sensitized to sporozoites of plasmodium berghei. | hybridoma cell lines, which secreted antibodies directed against either the surface of plasmodium berghei sporozoites or mosquito debris, were produced by fusion of spleen cells of p. berghei sporozoite-immunized mice with p3-x63-ag8 myeloma cells. four cloned antibody-secreting cell lines were successfully established. two of these clones (f9 and g10) were obtained from the fusion of spleen cells from mice that had undergone two immunizations. these clones produced an igm antibody that did not ... | 1982 | 6129292 |
| specific identification of plasmodium sporozoites using an indirect fluorescent antibody method. | the specific identification of plasmodial sporozoites is not possible on morphological grounds. this study presents a serological method for the identification of sporozoite species, indicating the suitability of this approach for detection and determination of sporozoites in wild vectors collected from malaria endemic areas. specific antisera and monoclonal antibodies prepared against each of two species of rodent malaria (plasmodium berghei or p. yoelii) were evaluated for their ability to dis ... | 1983 | 6137889 |
| the importance of disease induced changes in mammalian body temperature to mosquito blood feeding. | laboratory mice infected with rodent malaria (plasmodium berghei or p. chabaudi) or st. louis encephalitis virus (sle) were not hyperthermic during the infection period. however, all infected animals displayed pathogen-specific periods of hypothermia. hamsters infected with p. berghei were hyperthermic on day 7 postinfection (pi) but became hypothermic on day 8 pi and remained so until death, approximately 20 days pi. body temperatures of mice infected with p. yoelii were not significantly diffe ... | 1984 | 6142803 |
| identification of circumsporozoite proteins in individual malaria-infected mosquitoes by western blot analysis. | circumsporozoite (cs) proteins of rodent (plasmodium berghei), simian (p. knowlesi), and human (p. falciparum) malaria parasites extracted from dead and dried mosquitoes have been identified by the western blot (immunoblot) technique. dried mosquitoes which were laboratory-reared and infected with plasmodium or freshly dissected sporozoites were triturated in sample reducing buffer and the extracts electrophoresed in a 10% sds-polyacrylamide gel. after transferring the proteins to nitrocellulose ... | 1984 | 6145742 |
| [long-term preservation of malarial parasites at the temperature of liquid nitrogen: infectivity and the capacity for gamont formation]. | | 1984 | 6148688 |
| towards tumor therapy with interferons, part ii. interferons: in vivo effects. | | 1980 | 6155160 |
| effects of photosensitive chemicals on malaria parasite cells. | | 1980 | 6155821 |
| the dual role of macrophages in the sporozoite-induced malaria infection. a hypothesis. | | 1980 | 6156920 |
| the human materno-foetal relationship in malaria: i. identification of pigment and parasites in the placenta. | to facilitate investigations of the consequences of malarial infection during human pregnancy, several methods for the recognition of pigment and parasites in the placenta were evaluated. pigment was visualized in infected blood smears and placental tissue using both white light and modified fluorescence microscopy. however, the characteristic pigment dots observed with fluorescent light were also apparent in unstained cryostat and deparaffinized placental sections, and following reaction with i ... | 1980 | 6159702 |
| inhibition of p. falciparum growth in human erythrocytes by monoclonal antibodies. | malaria is increasing in incidence and prevalence in most tropical areas and is a major problem for both individuals and communities. current malaria research is aimed at developing vaccines and, for this, it may be useful to define plasmodium antigen(s) related to the development of a protective immune response in the host. monoclonal antibodies have recently been shown to interfere with rodent malaria infection (plasmodium berghei) at the sporozoite or merozoite stage. we have now raised monoc ... | 1981 | 6161311 |
| monoclonal antibodies to stage-specific, species-specific, and cross-reactive antigens of the rodent malarial parasite, plasmodium yoelii. | eighteen hybridoma cell lines were used to study species-specific, stage-specific, and serological cross-reactive antigens of the rodent malarial parasite, plasmodium yoelii. specificity and location of plasmodial antigens were determined by indirect fluorescent-antibody analysis. results showed that a minimum of 12 distinct plasmodial antigens could be distinguished by the 18 hybridomas. antigens were found on the surface or within the cytoplasm of the parasite, but not on the surface of erythr ... | 1981 | 6166558 |
| immunodepression of thymus-independent response to dextran in mouse malaria. | the thymus-independent antibody response to the alpha 1-6 epitope of dextran b512 was depressed strongly during acute non-lethal plasmodium yoelii yoelii malaria, but not during low-grade chronic plasmodium berghei infection. in the acute infection, which is self-limiting, the duration of severe immunodepression was short and was seen only in mice immunized at or around the time of peak parasitaemia. mice primed at this time responded normally to challenge 20 days later: thus the primary exposur ... | 1981 | 6167386 |
| protective reaction against malaria infection in mice sensitized with frozen-thawed toxoplasma tachyzoites. | mice sensitized with frozen-thawed toxoplasma antigen emulsified in freund's incomplete adjuvant (fia) showed high resistance against plasmodium berghei infection, but not in mice sensitized with paraformaldehyde-fixed. toxoplasma or saline plus fia. however, mice which survived from malaria infection did not show any protective reaction against the rh strain inoculation. furthermore, an immune interferon activity was detected in the supernatant of the spleen cells collected from the mice sensit ... | 1981 | 6171952 |
| [study of the glycolysis of erythrocytes by the method of automatic titration of lactic acid]. | | 1981 | 6172639 |
| plasmodium berghei: immunologically active proteins on the sporozoite surface. | | 1982 | 6174361 |
| the use of percoll gradients, elutriator rotor elution, and mithramycin staining for the isolation and identification of intraerythrocytic stages of plasmodium berghei. | intraerythrocytic parasites of plasmodium vinckei and plasmodium berghei were separated according to their developmental stages using discontinuous percoll gradients. contaminating nucleated blood cells such as leukocytes were removed by elutriation centrifugation. the stages were unequivocally identified in smears using a newly developed dna-specific staining procedure with mithramycin and fluorescence microscopy. this stain can also be used to detect parasites in human blood of very low parasi ... | 1982 | 6177116 |
| [protective action of specific gamma globulin against malaria caused by plasmodium berghei]. | | 1982 | 6179147 |
| the influence of dietary protein on the development of malaria. | in the course of malarial infection in an animal model, the dietary level of protein proved to be important. synthetic diets were used, identical in every respect other than the type and amount of protein. reducing the protein content of the diet led to a decrease in the level of infection and a protein-free diet almost totally suppressed the disease. these findings were obtained in rats infected with either plasmodium berghei or plasmodium vinckei; when the dietary protein was in the form of ca ... | 1981 | 6185057 |
| ultrastructural studies of a vesicle system associated with endoplasmic reticulum in exo-erythrocytic forms of plasmodium berghei. | fine structural studies of a specialized vesicle system associated with the endoplasmic reticulum (er) of exo-erythrocytic plasmodium berghei suggest that this system may be the equivalent of a golgi apparatus. patches of er, randomly distributed in the cytoplasm of developing parasites, are formed of smooth and ribosome-studded cisternae intermingled with each other. the vesicle systems are located between as well as at the edges of er aggregates and appear to be in different stages of budding ... | 1983 | 6191028 |
| anti-red blood cell autoantibodies induced in rat by plasmodium berghei infection bind to a cross-reacting determinant present also in other cell types. | it has been previously shown that rats injected with red blood cells (rbc) infected with plasmodium berghei make autoantibodies reacting with normal rat rbc as demonstrated by a staphylococcal protein a binding assay. in this study, the serum of the infected rats was found to contain also antibodies to several other types of rat cells (lymphoid, liver, and kidney cells and brain tissue) as well as against rbc and lymphoid cells of mice and sheep, but not of man. rat, mouse, and sheep rbc and rat ... | 1983 | 6191899 |
| [oxidative damage of mice erythrocytes infected with plasmodium berghei]. | by using the model of infection with plasmodium berghei in white mice the attempt was made to explain the oxidative damages of red blood cells as a cause for haemolysis. in addition to a diminished new formation of erythrocytes there was an increased cell lysis under the impact of infection. without any changes of the met-hb-percentage and of heinz bodies an increase of gsh and gssg could be measured. the conclusion was drawn that a damage of red blood cells caused by oxidation may occur by chan ... | 1983 | 6196273 |
| [effect of formate on mouse erythrocytes in vivo and in vitro]. | the effect of formiat was tested in erythrocytes of mice damaged by oxidisation. decrease of heinz's bodies, stabilisation of reduced glutathion, and increase of enzyme activities by referring to an example of superoxidismutase could be identified as a positive effect. possibilities of formiat reactions in the metabolism of red blood cells are discussed. | 1983 | 6200395 |
| cytochemical studies on nuclear dna of four eucoccidian parasites, isospora (toxoplasma) gondii, eimeria tenella, sarcocystis cruzi and plasmodium berghei. | feulgen-pararosaniline (so2) staining was performed on stages in the life-cycle of isospora (toxoplasma) gondii, eimeria tenella, sarcocystis cruzi and plasmodium berghei. the fluorescence emission of the stained dna in nuclei of these stages was examined and compared with absorption microscopy measurements at 560 nm (green light) of the same specimens. accurate identification of single cells, and especially discrimination between young schizonts and young gamonts was difficult after feulgen sta ... | 1984 | 6200820 |
| determination of nuclear dna of five eucoccidian parasites, isospora (toxoplasma) gondii, sarcocystis cruzi, eimeria tenella, e. acervulina and plasmodium berghei, with special reference to gamontogenesis and meiosis in i. (t.) gondii. | dna contents of individual stages of isospora (toxoplasma) gondii and other eucoccida were measured after feulgen-pararosaniline (so2) staining either by direct microfluorometry or by scanning of microphotographic negatives. frequency distributions were analysed using a computer program based on a mathematical model describing cell division. all stages of i. (t.) gondii, except fertilized macrogametes (2c), contained a haploid amount of dna (1c), indicating that meiosis in i. (t.) gondii occurs ... | 1984 | 6204268 |
| evolutionary conservation of histidine-rich protein genes and rnas in malaria parasites. | | 1984 | 6206515 |
| interactions between the intestinal flagellates giardia muris and spironucleus muris and the blood parasites babesia microti, plasmodium yoelii and plasmodium berghei in mice. | in mice infected with the intestinal flagellates giardia muris or spironucleus muris, together with the blood parasites babesia microti or plasmodium yoelii, there is a temporary decrease of flagellate cyst output coincident with the peak of the blood parasite infections, followed by a rapid return to normal levels. this decrease in cyst output is correlated with decreased numbers of trophozoites in the small intestine. the effect on s. muris is more marked than that on g. muris. neither blood p ... | 1982 | 6214756 |
| kinetics of immunosuppression of sporozoite-induced immunity by mycobacterium bovis bcg. | the data reported in this study demonstrate that the vaccination of nih/nmri mice with viable mycobacterium bovis bcg organisms induces a state of immunosuppression that renders the recipient animals incapable of a protective immune response to the malaria sporozoite vaccine. the expression of this altered protective immune response is dependent upon the dosage of the two live vaccines, as well as upon the sequence of their administration. data presented here show that the skin test responses (a ... | 1982 | 6215354 |
| [synthesis, toxicity and antimalarial effects of bispyroquine]. | | 1983 | 6223506 |
| plasmodium berghei: a mouse model for the "sudden death" and "malarial lung" syndromes. | a mouse model for the "sudden death" and "malarial lung" syndromes is described. mice of the c3h/z strain succumb suddenly approximately 7 days after an infection with plasmodium berghei becomes patent, at a time when parasitemia is still moderate (6 to 8%). death could be shown to be due to anaphylactoid shock, probably induced by soluble immune complexes. increased vascular permeability caused transudation and leakage of serum proteins into the interstitium and the alveoli. the lungs were foun ... | 1983 | 6223835 |
| prevention of cerebral malaria by adoptive transfer of malaria-specific cultured t cells into mice infected with plasmodium berghei. | murine t cell populations specific for plasmodium berghei parasites were generated in vitro from balb/c immune lymph node cells. the malaria-specific t lymphocytes were shown: a) to proliferate specifically in vitro in response to stimulation with p. berghei-infected red blood cells; b) to exhibit the thy-1+, lyt-1+2- cell surface phenotype; c) to provide specific helper activity for an in vitro anti-hapten (tnp) plaque-forming cell antibody response; and d) to protect p. berghei-infected mice f ... | 1983 | 6224859 |
| anti-lymphocyte antibodies in lethal mouse malaria. ii. induction of an autoantibody specific suppressor t cell by non-lethal p. yoelii. | the anti-lymphocyte autoantibody response to irradiated lethal plasmodium berghei malaria parasites in normal mice was significantly reduced when recipients were pre-treated with splenic t cells from mice recovered from a non-lethal plasmodium yoelii infection. suppression was specific for the autoantibody and did not affect the antibody response to the parasite. experiments involving sequential p. yoelii-p. berghei infections in situ revealed that recovery from p. berghei was possible when the ... | 1983 | 6225580 |
| [7 antimalarials in the treatment of mice experimentally infected with pyronaridine-resistant plasmodium berghei]. | | 1983 | 6230874 |
| changes in the capacity of macrophages and t cells to produce interleukins during murine malaria infection. | interleukin 1 (i1-1) produced by activated macrophages and interleukin 2 (i1-2) released by a subset of t lymphocytes upon antigen or mitogen stimulation are the soluble mediators involved in the mechanism of t-cell activation, proliferation, and differentiation. since these t-cell responses are depressed during malaria infection, the capacity of macrophages to produce i1-1 following lipopolysaccharide (lps) stimulation and that of lymphocytes to release i1-2 upon stimulation with concanavalin a ... | 1984 | 6231107 |
| [antimalarial activities of hydroxypiperaquine and its phosphate against plasmodium berghei and plasmodium cynomolgi]. | | 1984 | 6232823 |
| long-acting, repository antimalarial agents. duration of protection in mice and monkeys following administration of pyrimethamine pamoate. | the duration of protection from blood-stage malarial challenge following single injections of pyrimethamine pamoate was assessed in mice and monkeys. this duration was dose-related and ranged from several weeks in mice to over 4 months in the monkeys. comparisons with the previously reported repository drugs, cycloguanil pamoate and acedapsone (diacetyldiaminodiphenyl sulfone), in mice demonstrated that pyrimethamine pamoate provides an equal or greater duration of protection. studies with mixtu ... | 1984 | 6236702 |
| plasmodium yoelii and plasmodium berghei: isolation of infected erythrocytes from blood by colloidal silica gradient centrifugation. | | 1980 | 6248355 |
| plasmodium berghei: modification of sialic acid on red cells from infected mouse blood. | | 1981 | 6257538 |
| pyrimidine biosynthesis in plasmodium berghei. | | 1981 | 6260538 |
| a simple method for separation of uninfected erythrocytes from those infected with plasmodium berghei and for isolation of artificially released parasites. | rat erythrocytes infected with plasmodium berghei were disrupted by gentle passage of concanavalin a (con a) agglutinated cells through a 100 mesh stainless steel grid. the free parasites were separated from cell debris, unbroken infected cells, and from uninfected rat erythrocytes on a percoll gradient. the parasites remained morphologically intact, metabolically active, and infective to mice. the parasites were observed by light and electron microscopy. the incorporation of 3h-isoleucine and 3 ... | 1981 | 6261470 |
| cyclic amp metabolism in p. berghei infected murine red cells. | | 1981 | 6270696 |
| comparative studies on dihydroorotate dehydrogenase from p. berghei and the mouse reticulocyte. | kinetic parameters on dihydroorotate dehydrogenase (dho-dhase) from the rodent malarial parasite, plasmodium berghei, have been determined. this enzyme, the fourth in de novo pyrimidine biosynthesis, is particulate and is absent in the mature mammalian red cell. the km of the substrate, dihydroorotate, was determined to be 23 microm and the ki values for a number of substrate analogues have been determined. the most potent inhibitor was dihydroazaorotate (ki, 3 microm), 5-azaorotate (ki, 20 micr ... | 1981 | 6271112 |
| approaches to assessing host resistance. | there is increasing evidence that chronic, subclinical exposure to certain environmental pollutants may upset immune responsiveness and alter susceptibility of animals to infectious agents. environmental chemicals or drugs may affect diverse aspects of the immune system, leading to immunosuppression, immunopotentiation, hypersensitivity or perturbed innate host resistance. a variety of infectious models is available that involves relatively well defined target organs and host defense mechanisms; ... | 1982 | 6277617 |
| mechanism of diethyl-dithiocarbamate induced elevation of parasitemia in plasmodium berghei infection. | | 1982 | 6282744 |
| myristate-induced release of superoxide and hydrogen peroxide from peritoneal macrophages in mice immunized to toxoplasma gondii and plasmodium berghei. | | 1982 | 6290731 |
| synthesis and biological properties of 2'-deoxy-5-vinyluridine and 2'deoxy-5-vinylcytidine. | rapid and efficient syntheses for the preparation of 2'-deoxy-5-vinyluridine and 2'-deoxy-5-vinylcytidine are described starting from nucleoside precursors. contrary to some previous reports, 2-deoxy-5-vinyluridine has be found to be quite stable under normal laboratory conditions but when tested in animals shows neither toxicity nor anti-leukemic (l1210 cells) or anti-parasitic (plasmodium berghei) activity. 2'-deoxy-5-vinylcytidine appears to polymerise readily. it is much less toxic to cell c ... | 1982 | 6292837 |
| increased fluidity of plasmodium berghei-infected mouse red blood cell membranes detected by electron spin resonance spectroscopy. | | 1983 | 6302505 |
| the four ribosomal dna units of the malaria parasite plasmodium berghei. identification, restriction map, and copy number analysis. | the four ribosomal rna genes (rdna units) of the rodent malaria parasite, plasmodium berghei, were identified and mapped by restriction enzyme analysis and southern blot hybridization of genomic dna. although the four genes share common characteristics, they appear to be internally different from each other in expanse and sequence. one hindiii site near the 3' end of the coding region for the large rrna is the only restriction site which we have detected that is conserved in all of the genes. th ... | 1983 | 6304071 |
| membrane-associated phosphoproteins in plasmodium berghei-infected murine erythrocytes. | normal and plasmodium berghei (nyu-2 strain)-infected murine erythrocytes display substantially different patterns of plasma membrane phosphoproteins phosphorylation. intact erythrocytes (normal and parasite infected) incubated with 32pi and isolated washed erythrocyte plasma membranes incubated with gamma-32p-atp were analyzed for phosphoproteins by sds page and autoradiography. two new phosphoproteins of molecular weight 45,000 (pp45) and 68,000 (pp68), which are absent in normal erythrocyte m ... | 1983 | 6306014 |
| the enzymes of pyrimidine biosynthesis in babesia bovis and babesia bigemina. | all six enzymes of de novo pyrimidine biosynthesis leading to the formation of ump have been demonstrated in whole homogenates from two bovine babesia species, b. bovis and b. bigemina. the specific activities of the respective enzymes were of the same order of magnitude as observed for the related parasite, plasmodium berghei. the results indicate that both these parasites have the potential of obtaining their pyrimidine requirements by de novo synthesis. subcellular fractionation established t ... | 1983 | 6309129 |
| further studies and electron microscopic characterization of plasmodium berghei dna. | the average length and the interspersion pattern of repetitive dna sequences in the plasmodium berghei genome have been studied by electron microscopy. within the limitations posed by the relatively high genome complexity, analysis of partially renatured total dna indicates that repetitive sequences do not occupy preferential positions along the genome, but are widely dispersed (one in approx. 8000 base pairs of unique dna). structures appearing as loops flanked by inverted repeats are present. ... | 1983 | 6314137 |
| [higher microsomal monooxygenase activity in chloroquine-resistant strains of malarial plasmodium as a possible cause of drug stability]. | ability to hydroxylate benz(alpha)pyrene--a substrate of arylhydrocarbone hydroxylase (ahh) was distinctly increased in lysates of erythrocytes containing malarial plasmodium. hydroxylation of benz(alpha)pyrene was inhibited by methyrapone--an inhibitor of microsomal monooxygenases. activity of ahh was increased from 2- to 3-fold in chloroquine-resistant plasmodium strains as compared with the drug-sensitive strains. resistance of plasmodium berghei to chloroquine appears to involve an activatio ... | 1983 | 6316663 |
| ketoconazole and other potent antimycotic azoles exhibit pronounced activity against trypanosoma cruzi, plasmodium berghei and entamoeba histolytica in vivo. | | 1984 | 6320547 |
| plasmodium berghei: electron spin resonance and lipid analysis of infected mouse erythrocyte membranes. | red blood cells from mice infected with plasmodium berghei and from uninfected mice were labeled with stable, free radical derivatives of stearic acid. electron spin resonance spectra of these samples showed that the degree of molecular order in these membranes decreased, and the rate of motion of the probe increased, with increasing levels of parasitemia. parasitemia increased the ratio of unsaturated to saturated 18-carbon fatty acids, and decreased the percentage of arachidonic acid and of ch ... | 1984 | 6325227 |
| serological reactivity of in vitro cultured exoerythrocytic stages of plasmodium berghei in indirect immunofluorescent or immunoperoxidase antibody tests. | exoerythrocytic (ee) stages of plasmodium berghei were cultivated in vitro in wi38 cells inoculated with sporozoites, and examined for serological reactivity by indirect immunofluorescent or immunoperoxidase tests. at 24 hours post-inoculation, sporozoite and red blood cell (rbc) stage antigens were equally distributed, but by 48 hours, rbc stage antigens predominated. merozoites, produced by 72 hours, reacted strongly with anti-rbc stage sera, but were weakly reactive with anti-sporozoite sera. ... | 1983 | 6337518 |
| pathogenesis of cerebral malaria in golden hamsters and inbred mice. | | 1983 | 6337774 |
| endomyocardial lesion and endomyocardial fibrosis in experimental malaria (plasmodium berghei) in mice. | | 1983 | 6337776 |
| composition and kinetics of immune complexes in mice infected with plasmodium berghei. | | 1983 | 6337777 |
| structural similarities among the protective antigens of sporozoites from different species of malaria parasites. | | 1983 | 6338017 |
| malaria renders mice susceptible to mosquito feeding when gametocytes are most infective. | mice infected with plasmodium berghei, p. chabaudi, or p. yoelii became lethargic and ceased to display normal antimosquito behavior. periods of reduced defensiveness corresponded with maximum mosquito engorgement and with periods of maximum gametocyte infectivity to mosquitoes. increased feeding success of mosquitoes during periods of peak gametocyte infectivity may be important to the natural maintenance of these malaria parasites. | 1983 | 6338190 |
| 2-acetylpyridine thiosemicarbazones. 5. 1-[1-(2-pyridyl)ethyl]-3-thiosemicarbazides as potential antimalarial agents. | reduction of the azomethine bond of 2-acetylpyridine thio- and selenosemicarbazones with sodium borohydride readily afforded the corresponding thio- or selenosemicarbazides when they were n4,n4-disubstituted. this conversion failed, however, when the thio- or selenosemicarbazones were n4-substituted or unsubstituted. a more general route to the desired thio- or selenosemicarbazides consisted of reduction with sodium borohydride of methyl 3-[1-(2-pyridyl)ethylidene]hydrazinecarbodithioate to give ... | 1983 | 6338234 |
| malaria parasites--discovery of the early liver form. | infections of mammalian malaria parasites start when sporozoites from an infected anopheline mosquito are injected into the bloodstream of the host. the sporozoites enter the hepatocytes and become transformed into exoerythrocytic schizonts. since the discovery of the primate parasite plasmodium cynomolgi in monkey hepatocytes and the rodent parasite plasmodium berghei in hamster hepatocytes, the ultrastructure of these stages has been extensively studied both in primate and rodent plasmodia. th ... | 1983 | 6339945 |
| enhanced expression of h-2k and h-2d antigens on reticulocytes infected with plasmodium yoelii. | the 17xnl strain of plasmodium yoelii induces a highly effective and permanent t-cell dependent immunity in mice of the cba strain; the lethal variant p. yoelii 17xl and p. berghei (anka) fail to activate an effective immune response in the same host. these differences in immunogenicity are unexplained. we recently observed that in cba/caj mice the intracellular blood stages of p. yoelii 17xnl were almost exclusively within reticulocytes whereas lethal p. yoelii 17xl and p. berghei (anka), at co ... | 1983 | 6339952 |
| antiparasitic activity of natural and semisynthetic monensin urethanes. | a total of 17 monensin urethanes, including two naturally produced phenethylurethanes (streptomyces sp.), were evaluated for antiparasitic activity. all of the compounds had the characteristic properties of the polyether antibiotics including their ability to transport cations across membranes. several of the semisynthetic derivatives demonstrated in vitro and in vivo anticoccidial activity in chickens. in vitro activity was shown utilizing chick kidney cell culture experimental procedures in wh ... | 1983 | 6340991 |
| protective immunity to malaria and anti-erythrocyte autoimmunity. | the intraerythrocytic development of malaria parasites results in considerable modification and destruction of erythrocytes. this may lead to the breaking of tolerance such that immune recognition of 'self' or 'modified self' erythrocyte antigens by b or t lymphocytes occurs. such recognition may be a vital factor in the induction of protective immunity even though it may also cause immunopathology. serological and immunocytochemical assays have been used to demonstrate, in the serum of plasmodi ... | 1983 | 6340999 |
| mode of action of antimalarial drugs. | chloroquine, quinine, quinacrine and related drugs are effective antimalarial agents only against parasites that degrade haemoglobin. this fact prompted an examination of the role of ferriprotoporphyrin ix (fp), a product of haemoglobin degradation, in the mode of action of chloroquine. fp was identified as a high affinity drug receptor of malaria parasites by showing that it has the appropriate affinity for chloroquine, with a dissociation constant on the order of 10(-8) m, and specificity for ... | 1983 | 6341003 |
| the spleen in malaria. | the mechanisms underlying splenic host defence in malaria have not been precisely defined but they include both immunological and non-immunological interactions with parasitized erythrocytes. studies of the intravascular clearance of 51cr-labelled plasmodium berghei-infected erythrocytes in the rat show that these cells are cleared predominantly by the spleen, and to a greater extent in immune than non-immune animals. transfer of hyperimmune rat serum imparted protection to challenge with p. ber ... | 1983 | 6341005 |
| feeding patterns of mosquitoes (diptera: culicidae) simultaneously exposed to malarious and healthy mice, including a method for separating blood meals from conspecific hosts. | | 1983 | 6341591 |
| role of macrophage-processed antigen in a plasmodium berghei model. | the present study demonstrates that malarial parasite could be processed by macrophages in vitro to release 'super antigens'. these super antigens obtained from the peritoneal macrophages were more protective than those processed by the splenic adherent cells. bcg-stimulated macrophages were also able to process the antigens efficiently and these antigens were even superior to those obtained from the unstimulated macrophages. these modified antigens were potent inducers of dfps to malarial antig ... | 1983 | 6341933 |
| t-independent macrophage changes in murine malaria. | a study to investigate the participation of t cells in macrophage-mediated responses during malaria was performed in nude (nu/nu) and littermate (nu/+) mice infected with plasmodium berghei (pb). we found that in both groups of mice spleen cells suppressed the mitogenic response to lps. both nu/+ and nu/nu infected mice also showed liver macrophage activation, reflected by increased plasminogen activator release. these findings suggest that at least some of the macrophage changes during malaria ... | 1983 | 6342882 |
| plasmodium berghei: diet and drug dosage regimens influencing selection of drug-resistant parasites in mice. | two different diets for the host and three drug dosage regimens were used to select lines resistant to sulfadoxine and pyrimethamine from the parent strain of the rodent malaria parasite plasmodium berghei [the n (k173) strain]. a higher yield of resistance was obtained when a high parasitemia was present at the beginning of the drug pressure schedule. the development of resistance to the association of sulfadoxine plus pyrimethamine was accelerated by a relatively high para-aminobenzoic acid (p ... | 1983 | 6343110 |
| host defenses in murine malaria: characteristics of protracted states of immunity to plasmodium berghei. | vaccination of 8-week-old b6d2 (c57bl/6 x dba/2) mice with formalin-killed asexual erythrocytic stages of plasmodium berghei provided a capacity to survive challenge with lethal p. berghei for more than 542 days. although long-lived, this immunity did not provide a capacity to immediately neutralize parasites in a challenge; significant levels of erythrocytic infection occurred transiently after each challenge. the quality of long-lived immunity was not enhanced by an injection of live parasites ... | 1983 | 6343244 |
| in vitro culture of plasmodium berghei using a new suspension system. | | 1983 | 6343271 |
| expression of cell-mediated antimicrobial immunity by mouse trophoblast monolayers. | monolayers of mouse trophoblast cells were produced after short-term culture (two to four days) of ectoplacental cone cells derived from 7.5-day-old mouse conceptuses and were then tested for phagocytic activity. following brief intervals of coincubation with the blood stage form of plasmodium berghei, the parasite that causes rodent malaria, cultured trophoblast cells were found to phagocytose large amounts of parasitic material. in a manner similar to that of peritoneal macrophages, trophoblas ... | 1983 | 6343521 |
| hematopoietic tissue in malaria: facilitation of erythrocytic recycling by bone marrow in plasmodium berghei-infected mice. | in p. berghei murine malaria, parasitized erythrocytes and nonparasitized reticulocytes were concentrated in the lumen of venous sinuses of bone marrow, adherent to endothelium and to one another. merozoites maturing in erythrocytes contained in venous sinuses are so positioned against adherent reticulocytes that when they break out they can penetrate adherent reticulocytes without significant extracellular exposure. merozoites from cells not adjacent to reticulocytes would spill into the plasma ... | 1983 | 6343573 |
| the influence of cell type and culture medium on the in vitro cultivation of exoerythrocytic stages of plasmodium berghei. | plasmodium berghei sporozoites successfully entered and developed into exoerythrocytic schizonts in a variety of cell types cultured in vitro, but segmentation and release of merozoites was only observed in human embryonic lung cells. exoerythrocytic development was generally not influenced by the culture medium, and nctc-135 was used routinely. in vitro infectivity of p. berghei sporozoites was unaffected by the serum type used for isolation. | 1983 | 6343574 |
| free-flow electrophoretic separation of plasmodium berghei sporozoites. | sporozoites of the rodent malaria, plasmodium berghei, were obtained from infected anopheles stephensi by grinding mosquitoes, prepurifying the material in a discontinuous hypaque gradient and further purifying by means of continuous free-flow electrophoresis. bacteria, debris, mitochondria, mitoplasts, and other contaminants were removed in the electric field. the isolated sporozoites were morphologically intact and were positive in indirect immunofluorescence assay. they were infective to mice ... | 1983 | 6343576 |
| an ultrastructural study on the role of kupffer cells in the process of infection by plasmodium berghei sporozoites in rats. | the interactions in vivo between plasmodium berghei sporozoites and kupffer cells in rat livers were studied by transmission electron microscopy. by 10 and 15 min after inoculation, sporozoites were both free in the liver sinusoids and inside endocytotic vacuoles of the kupffer cells. the latter cells were very active in phagocytosing sporozoites, bacteria and red blood cells. the sporozoites retained their integrity inside the endocytotic vacuoles and no signs of lysosomal digestion were observ ... | 1983 | 6343960 |
| [studies on synthetic antimalarials. vi. the synthesis and antimalarial activity of some new piperaquine analogues , tripiperaquines]. | | 1983 | 6344554 |
| antilymphocyte autoantibody in lethal mouse malaria and its suppression by non-lethal malaria. | mice infected with lethal p. berghei or p. yoelii malaria develop anti-lymphocyte autoantibodies less than a week after infection. the autoantibodies are igm, t-dependent and cytotoxic to a subpopulation of non-t lymphocytes at 37 degrees c in the presence of mouse or guinea-pig complement. non-lethal p. yoelii and p. chabaudi do not induce these autoantibodies. x-irradiated p. berghei parasites induce autoantibodies in normal mice but not in mice infected with non-lethal p. yoelii suggesting an ... | 1983 | 6346230 |
| malaria parasites adopt host cell superoxide dismutase. | aerobic organisms depend on superoxide dismutase to suppress the formation of dangerous species of activated oxygen. intraerythrocytic stages of the malaria parasite exist within a highly aerobic environment and cause the generation of increased amounts of activated oxygen. plasmodium berghei in mice was found to derive a substantial amount of superoxide dismutase activity from the host cell cytoplasm. plasmodia isolated from mouse red cells contained mouse superoxide dismutase, whereas rat-deri ... | 1983 | 6348944 |
| in vitro cultivation of the exoerythrocytic stage of plasmodium berghei in a hepatoma cell line. | when inoculated with sporozoites of plasmodium berghei, a line of hepatoma cells (hepg2-a16) derived from human liver supports the complete asexual developmental cycle of the exoerythrocytic stage. parasites were shown to resemble parasites in vivo in hepatocytes. subinoculation of merozoites into mice induced a red blood cell infection. | 1983 | 6349397 |
| entry of plasmodium berghei sporozoites into cultured cells, and their transformation into trophozoites. | the attachment and entry of plasmodium berghei sporozoites to cultured human lung fibroblast (wi38) or hepatoma (hepg2-a16) cells in vitro has been visualized using an immunoperoxidase technique coupled with light microscopy. attachment and entry was substantially more frequent with hepg2-a16 cells, and appeared to be mediated by the pb44 sporozoite surface protective antigen. when sporozoites were incubated with intact monoclonal antibodies to pb44 or their monovalent fab fragments, attachment ... | 1983 | 6349398 |
| conversion of glucose of lactate by intraerythrocytic plasmodium berghei. | there have been many reports that intraerythrocytic plasmodium berghei does not metabolize glucose completely to lactate. however, it appears that in some circumstances there can be interference with the assay of lactate. correction by a dilution method suggests that in reality conversion is essentially complete. | 1983 | 6349559 |
| immune phagocytosis of plasmodium berghei parasites by mononuclear phagocytes. | | 1983 | 6349830 |
| antibody-independent immunity to reinfection malaria in b-cell-deficient mice. | immunity to "reinfection malaria" or "premunition" was studied in b-cell-deficient mice which had previously experienced acute malaria caused by the avirulent plasmodia plasmodium yoelii or p. chabaudi or by the lethal p. vinckei. such mice resisted challenge infection with large numbers of homologous parasites but differed in their capacity to resist challenge with heterologous species. mice immune to p. yoelii resisted infection with p. chabaudi but developed acute-type, albeit nonlethal, infe ... | 1983 | 6350181 |
| arylmethanol and thiosemicarbazone influence of plasmodial macromolecular synthesis and cell stability. | the influence of mefloquine and additional antimalarial drugs on (3h)adenosine uptake, macromolecular synthesis, and cell stability was determined in rodent red cells parasitized with plasmodium berghei. high arylmethanol to cell ratios induced lysis, whereas inhibition of macromolecular synthesis occurred at lower drug/cell ratios. a 2-acetylpyridine thiosemicarbazone rapidly suppressed (3h)adenosine uptake, and also blocked macromolecular synthesis by parasitized cells. | 1983 | 6350781 |
| isolation and characterization of membrane proteins of plasmodium berghei sporozoites. | two immunologically significant proteins, sp53 and sp110, have been isolated from the sporozoites of plasmodium berghei anka strain using different extraction procedures. in gel filtration studies the physicochemical characteristics of sp53 and sp110 appeared to be somewhat different. both polypeptides could be purified using sephacryl s300 column chromatography. the possible relationship of both sp53 and sp110 with sporozoite proteins described by other investigators is discussed. | 1983 | 6350869 |
| enhanced ca2+ uptake by mouse erythrocytes in malarial (plasmodium berghei) infection. | erythrocytes from plasmodium berghei-infected mice on incubation either in plasma or artificial isotonic media showed an increase in uptake of 45ca2+ compared with erythrocytes from uninfected mice. infected cells (55% parasitaemia) incubated in plasma from normal or infected mice gave uptake rates of 9.8 and 8.1 nmol h-1 per 10(10) cells, assuming equilibrium between added 45ca2+ and plasma ca2+. uptake rates of erythrocytes from infected mice were increased in the presence of glucose, with a r ... | 1983 | 6350870 |
| plasmodium berghei: influence on granulopoiesis and macrophage production in balb/c mice. | granulocyte and macrophage progenitor cells forming colonies in vitro (gm-cfc) from bone marrow, spleen, and peripheral blood of balb/c mice infected with plasmodium berghei were cultured at various times postinfection in a viscous, 0.8% methylcellulose system. the numbers of gm-cfcs from bone marrow increased gradually during the first week of infection, reaching a maximum around the tenth day of the disease. subsequently, a rise of gm-cfcs in cultures of nucleated cells from the peripheral blo ... | 1983 | 6352322 |
| cloning and characterization of a ribosomal rna gene from plasmodium berghei. | the ribosomal rna (rrna) of plasmodium berghei strain nyu2 was characterized with respect to size and used to identify molecular clones of ribosomal rna genes (rdna) from this organism. the intact large rrna species (mr 1.40 x 10(6] is intermediate in size between prokaryotic and eukaryotic large rrnas. it is specifically cleaved in vivo near the 5'-end yielding one large component (mr 1.10 x 10(6] and one small component (mr 0.30 x 10(6]. the small rrna species (mr 0.75 x 10(6] is larger than i ... | 1983 | 6353227 |
| effect of trauma on malaria infection. | | 1983 | 6353779 |
| an in vitro assay system for the identification of potential antimalarial drugs. | current models for antimalarial drug screening generally measure the survival of drug-treated rodents infected with plasmodium berghei. modifications of existing continuous culture methods for p. falciparum allow the rapid, accurate and economical determination of drug effects directly against the human pathogen. parasite cultures can be maintained in rpmi 1640 medium supplemented with human or rabbit serum or with hypoxanthine-supplemented bovine serum. the antiparasite effects of four drugs, c ... | 1983 | 6355423 |
| ultrastructural observations on the infection of rat liver by plasmodium berghei sporozoites in vivo. | the invasion of liver parenchymal cells by sporozoites of plasmodium berghei vincke & lips, 1948, was studied in vivo using transmission electron microscopy. livers of brown norway rats were examined 30 and 60 min after intraportal injection of 15 million sporozoites each. sporozoites found after incorporation into vacuoles in hepatocytes were often located near a bile canaliculus at the lateral cell surface, surrounded by hepatocyte lysosomal structures; however, degradation of sporozoites caus ... | 1983 | 6355454 |
| heterologous immunity in rodent malaria: comparison of the degree of cross-immunity generated by vaccination with that produced by exposure to live infection. | the degree of heterologous immunity occurring between the different rodent malarias was examined. mice immunized with a killed vaccine consisting of formalin-fixed blood-stage parasites mixed with saponin, were challenged with homologous or heterologous parasites and the degree of protection assessed by monitoring the number of survivors and the duration and severity of parasitaemia. the results indicated that vaccination conferred strong cross-protection between two different plasmodium yoelii ... | 1983 | 6357121 |
| failure to induce splenomegaly in balb/c mice using rodent malaria culture supernatants. | uninfected male and female balb/c mice were given a twice weekly intraperitoneal injection, of supernatants obtained from 24-h cultures of plasmodium berghei-infected and control mouse red blood cells, for 5 weeks. the mice were then weighed along with uninjected controls. all the animals were sacrificed by chloroform anaesthesia and their spleen weights measured. mice receiving malaria culture supernatants had statistically similar spleen weights to those receiving control culture supernatants. ... | 1983 | 6358008 |
| malaria-induced lymphokines: stimulation of macrophages for enhanced phagocytosis. | culture supernatants from antigen-pulsed spleen cells of mice infected previously with either bcg or plasmodium chabaudi were used to study macrophage activation as judged by phagocytosis of immunoglobulin g-sensitized erythrocytes and plasmodium berghei- and p. chabaudi-infected erythrocytes. resident peritoneal macrophages were incubated in vitro with spleen cell factor and then assayed for ingestion of immunoglobulin g-sensitized or parasitized erythrocytes. macrophages activated with bcg-ind ... | 1983 | 6358030 |
| [effect of a milk diet on parasitemia suppression and on the development of humoral immunity during the course of malarial infection in mice]. | | 1983 | 6358774 |