| the epidemiology of toxoplasmosis on iowa swine farms with an emphasis on the roles of free-living mammals. | multiparous sows from 19 central iowa swine farms were tested for antibodies against toxoplasma gondii by the modified direct agglutination test. antibody titers of 1:32 or greater were considered positive. rodents, domestic cats, opossums (didelphis virginiana), raccoons (procyon lotor) and striped skunks (mephitis mephitis) were live-trapped on each farm and similarly tested for antibodies. the overall prevalence of t. gondii antibodies in the species tested was 39/273 (14.3%) swine, 31/74 (41 ... | 1992 | 1496780 |
| rat model of congenital toxoplasmosis. | a rat model of congenital toxoplasmosis is described for the study of protective immunity and chemotherapy during pregnancy. six sprague-dawley 7- to 15-day gestational rats were inoculated orally (three rats, trial a) or subcutaneously (three rats, trial b) with 10,000 infective oocysts of the ct-1 strain of toxoplasma gondii. the tissues of rat pups born from these rats were bioassayed for t. gondii infection. t. gondii was recovered from 30 of 33 (90.9%, trial b) and 23 of 28 (82.17%, trial a ... | 1991 | 1879945 |
| macrophage-mediated fungistasis: requirement for a macromolecular component in serum. | peritoneal macrophages from mycobacterium bovis- or toxoplasma gondii-infected mice cultured in vitro in dulbecco's medium containing 10% fetal bovine serum (fbs) and endotoxin stopped replication of cryptococcus neoformans for 30 hr, whereas yeast cells cultured alone reproduced with a 3.0-hr doubling time. without at least 5% fbs, macrophage fungistasis was poor. fbs without macrophages enhanced the growth rate of cryptococci. macrophages preincubated in vitro for 24 hr without serum became fu ... | 1986 | 3522734 |
| [synthesis of toxins in parasitism by toxoplasma gondii]. | | 1966 | 5296796 |
| epidemiology of toxoplasmosis in kuwait. ii. toxoplasma gondii in the desert rodent, meriones crassus. | | 1980 | 7210127 |
| [on the propagation of toxoplasma gondii for the sabin and feldman reaction]. | | 1972 | 4669363 |
| rat macrophage activity against toxoplasma gondii studied by electron microscopy. | an electron microscope model was used to study the effect of rat peritoneal macrophages on toxoplasma gondii. 10(7) tachyzoites were injected i.p. in 30 days-old rats. after 1, 2, 4, 8 and 24 h peritoneal exudate was withdrawn and infected phagocytic cells were prepared for electronic microscope studies. toxoplasma organisms inside of rat macrophages showed remarkable lesions such as vacuolization and organisms were totally lysed inside of macrophages of more than 8 h infection rats. the results ... | 1986 | 3671808 |
| epidemiologic observations on infection with toxoplasma gondii in three species of urban mammals from baltimore, maryland, usa. | the prevalence of antibodies to toxoplasma gondii was determined in three species of domestic and commensal mammals, from baltimore, maryland, usa. crude prevalences of infection were 14.5% in cats (n = 650), 32.2% in dogs (n = 233), and 49.5% in norway rats (n = 109). oocysts identical to t. gondii were detected in 0.5% of cat feces. cats and rats showed antibody prevalence rates which were strongly age-(or some age-related variable) dependent, with the highest rates associated with older anima ... | 1986 | 3557837 |
| a review of toxoplasmosis of animals in the u.s.s.r. | information on the serologic and parasitologic prevalence of toxoplasma gondii infection in domestic and wild animals of the u.s.s.r. is reviewed. although complement-fixing antibodies to t. gondii were widely prevalent in animals, little information is available on the presence of viable t. gondii in tissues of animals. reports of epizootics in which t. gondii was suspected to be the causative agent of toxoplasmosis are summarized. also, the strict economic impact of toxoplasmosis on agricultur ... | 1986 | 3518211 |
| induction of a protective antibody-dependent response against toxoplasmosis by in vitro excreted/secreted antigens from tachyzoites of toxoplasma gondii. | toxoplasma gondii is a worldwide protozoan parasite which causes severe disease in congenitally infected children and in immunocompromised patients. besides the well-defined cytoplasmic and membrane antigens of tachyzoites, we felt that excreted/secreted antigens could play a major role in the immune response. we first report the development of a well-controlled procedure for obtaining tachyzoite excreted/secreted antigens (e/sa) in cell-free incubation media. the e/sa immunogenic in human, rat ... | 1988 | 3194150 |
| resistance to avirulent toxoplasma gondii in normal and vaccinated rats. | investigation of the innate resistance to infection with toxoplasma gondii showed that the toxoplasma-hostile factor present in rats has an important lytic effect on the parasites but is unable to prevent an infection alone. vaccination experiments showed that innate resistance was also related to specific immunity, which appeared faster in rats than in rodents with less innate resistance. complete resistance to toxoplasmosis was only present in rats vaccinated with live parasites. in rats vacci ... | 1988 | 3166808 |
| [infection of the athymic rat by toxoplasma gondii]. | in contrast to normal rats which are resistant to t. gondii infection (10(7) tachyzoïtes), athymic rats did not survive an intraperitoneal infection with 10(3) toxoplasma. when nude rats were injected intravenously with lymph node cells from hirsute littermates, they became resistant in a dose-dependent manner to the infection. in addition, reconstituted athymic rats having survived for more than 4 months the first infection were also protected against a second challenge with 10(5) tachyzoïtes. ... | 1987 | 3103874 |
| oxygen-independent killing by alveolar macrophages. | we have found that normal alveolar macrophages can kill an intracellular parasite by a mechanism that does not involve toxic metabolites of oxygen. we studied the interaction between toxoplasma gondii and rat alveolar macrophages in vitro. we were interested in toxoplasma because it causes pneumonia in immunosuppressed patients but not in healthy individuals, and we chose the rat because it resembles immunocompetent human subjects in being resistant to t. gondii. resident rat alveolar macrophage ... | 1986 | 3009680 |
| modulation of rat bronchoalveolar lavage cell function by the intratracheal delivery of interferon-gamma. | to determine if there is a rationale for compartmentalized immunostimulation, we have carried out a series of experiments to evaluate whether intratracheal delivery of interferon-gamma (rratifn-gamma) can activate rat bronchoalveolar lavage cells (bal) for in vitro expression of tumoricidal activity against xenogeneic p815 tumor cells and enhanced in vitro microbicidal activity against the intracellular protozoan toxoplasma gondii. treatment of rat alveolar macrophages in vitro activates them fo ... | 1988 | 2837520 |
| treatment with anti-l3t4 (cd4) monoclonal antibody reduces the inflammatory response in toxoplasmic encephalitis. | toxoplasma gondii is an important cause of disease of the central nervous system in patients with aids. among the variety of immunologic disorders encountered by aids patients is a depletion of cd4+ subpopulation of lymphocytes. in order to determine the role of this population of t lymphocytes in the generation of toxoplasmic encephalitis, mice chronically infected with t. gondii were treated with mab gk1.5 directed against the cell surface glycoprotein l3t4 (cd4) of t lymphocytes. histopatholo ... | 1989 | 2783605 |
| toxoplasma gondii antibody in patients of lepromatous leprosy. | sera from 140 lepromatous leprosy patients (test group) and 120 normal persons, who showed no clinical signs of acute or chronic toxoplasmosis (control group), were studied for the presence of toxoplasma gondii antibody by indirect hemagglutination and indirect-immunofluorescent antibody tests. both tests showed a high incidence of toxoplasma antibody in the test group in comparison with the control group. igm and igg classes of antibody responses were observed in both the groups, which signifie ... | 1989 | 2699622 |
| [antigens of toxoplasma gondii with a diagnostic and potential immunoprophylactic value: new strategies of identification]. | toxoplasma gondii is an ubiquitous protozoan parasite which induces severe pathology in in utero infected children and in immunosuppressed patients (particularly in the case of aids). previous work that focused on toxoplasma somatic antigens failed to demonstrate an efficient protection against highly virulent t. gondii strains. the authors therefore first studied the role of parasite excreted-secreted (es) antigens in the immune response. they describe here the preparation of excreted-secreted ... | 1989 | 2479305 |
| characterization of dihydrofolate reductase of pneumocystis carinii and toxoplasma gondii. | pneumocystis carinii and toxoplasma gondii are opportunistic pathogens of immunosuppressed patients that are susceptible to therapy with inhibitors of dihydrofolate reductase (dhfr). the dhfr of these two organisms was characterized to facilitate the identification of more selective inhibitors. similar to all reported protozoa, t. gondii has a bifunctional enzyme, of 120,000 da, that possesses both dhfr and thymidylate synthase (ts) activity. unexpectedly, p. carinii dhfr activity was present on ... | 1990 | 2354716 |
| [inter- and intra-cephalic variations in pathogenicity in toxoplasma gondii. clinical and epidemiologic consequences]. | clinical and epidemiological studies, especially the ones conducted in hiv+ patients indicate that the pathogenicity of toxoplasma gondii varies according to the strain considered. the differences observed among strains are represented by distinct genomic dna patterns which could be experimentally evaluated by means of the rflp (restriction fragment length polymorphism) and the rapd (random amplified polymorphic dna). if on the one hand virulent strains present very similar genomic dna patterns, ... | 1993 | 8193946 |
| antigen induced inhibition of autoimmune response to rat male accessory glands: role of thymocytes on the efferent phase of the suppression. | in the present study, we report that cy-sensitive, mrag-adherent spleen mononuclear (spm) inductor-phase t suppressor (ts) cells obtained from rats pretreated with low doses of a purified fraction (fi) of rat male accessory gland antigens (rag) are mainly ox19+ and w3/25+. furthermore, thymocytes from rats pretreated with fi of rag restore the suppression of the autoimmune response to rag autoantigens in irradiated recipients of spm inductor-phase ts cells. in contrast, thymocytes from rats pret ... | 1991 | 1838012 |
| impairment of natural resistance to toxoplasma gondii infection in rats treated with beta adrenergics, beta blockers, corticosteroids or total body irradiation. | the data shows that fisher rats treated with propranolol, betamethasone or exposed to cobalt60-treatment before challenge with t. gondii exhibit an impaired resistance to this opportunistic parasite infection. in fact, in rats propranolol-treatment induces an increase mortality rate up to 66.6% (p < 0.01, with respect to controls). whereas betamethasone or cobalt60-treatment induces an increased of mortality rate about 33.3% (p < 0.05 respectively, with respect to unirradiated rats). in contrast ... | 1993 | 8233643 |
| [absorption of human serum antibodies against toxoplasma gondii using tachyzoites from the rh strain]. | absorption experiments to determine the number of t. gondii tachyzoites to extract the anti-toxoplasma antibodies present in the human serum were carried out. the antibodies titer from each serum (n = 4) was determined by means of the sabin-feldman test (dye test). ten millions of tachyzoites were sufficient to absorb the antibodies from sera presenting titer 1:16, 1:64 and 1:256. on the other side, the absorption of a 1:512 positive serum with 10 x 10(6) t. gondii decreased the titer to 1:64 an ... | 1992 | 1307004 |
| the detection of hammondia hammondi in australia and the identification of a free-living intermediate host. | a cat fed commercially prepared cat food and free-living rats (rattus rattus and r. norvegicus) passed coccidian oocysts which were morphologically similar to toxoplasma gondii. mice dosed with these oocysts did not develop toxoplasmosis, but instead developed small, thin-walled parasitic cysts containing small bradyzoites in their striated muscles. these cysts measured 35 to 90 micron by 9 to 40 micron and they resembled cysts of hammondia hammondi. unlike t. gondii this coccidian parasite was ... | 1978 | 735301 |
| biology of toxoplasma gondii. | in conclusion, a large body of new information on the biology and immunology of t. gondii has accumulated in the past several years. much of this is due to the advent of aids and the increased funding made available to researchers interested in opportunistic infections in this patient population. these scientific advances have led to a better understanding of the process by which toxoplasma infects mammalian host cells, molecular biology and biochemistry of the parasite, antigenic structure and ... | 1993 | 8471191 |
| the prevalence of serum antibodies to toxoplasma gondii in ontario mammals. | the prevalence of seropositive reactions to toxoplasma gondii was studied in farm animals, companion animals, wild rodents and birds. of the animals tested, 17% of cattle, 65% of sheep, 45% of pigs, 9% of horses, 33% of dogs and 20% of cats were seropositive by the sabin-feldman dye test. in addition 11% of mice (mus musculus), 5% of deer mice (peromyscus), 3% of rats (rattus norvegicus) and less than 2% of sparrows (passer domestcus) were seropositive. all samples from short-tailed field mice ( ... | 1978 | 667705 |
| occurrence and attempted transmission of toxoplasma gondii in european starlings (sturnus vulgaris). | serums of 563 fledgling starlings (sturnus vulgaris) trapped during a 14 month period near lodi, california were examined for antibodies to toxoplasma gondii using the microtiter indirect hemagglutination method. titers ranging from 1:64 to 1:512 were found in 4.8% of the birds. starlings collected during may through october had a higher prevalence of antibody than those collected during november through april. rats inoculated with individual heart and brain suspensions from 10 seropositive star ... | 1978 | 650781 |
| serologic survey for toxoplasma gondii in wild animals in florida. | blood samples were collected for serum separation from 114 species of wild animals (25 species of mammals, 82 species of birds, and 7 species of reptiles) in florida. each of the 3,471 samples was tested for antibodies to toxoplasma gondii, using the indirect hemagglutination test. the highest prevalences of t gondii antibodies were 19% in armadillos (dasypus novemcinctus), 18% in raccoons (procyon lotor), 13% in black rats (rattus rattus), and 11% in opossums (didelphis marsupialis). antibody p ... | 1979 | 521384 |
| [role of toxoplasma gondii in human and animal chromosomal pathology]. | toxoplasma gondii was found to cause an appearance of cells with a changed number of chromosomes in the bone marrow of infected white rats. besides the increase of aneuploid and polyploid cells the infection with toxoplasms inhibits the mitotic activity in bone marrow of rats. the similar changes were observed in blood leucocytes of toxoplasmosis patients. | 1979 | 440780 |
| influence of chronic toxoplasma infection on ethylnitrosourea-induced central nervous system tumors in rats. | because prior work with mice had revealed remarkable inhibition of central nervous system (cns) tumor by chronic toxoplasma infection, the effect of immunomodulation produced by this obligate intracellular parasite was studied in rats which developed cns tumors following transplacental exposure to the chemical carcinogen ethylnitrosourea. groups of fischer 344 rats which had been exposed to ethylnitrosourea were either uninfected or infected at 1 month of age with a virulent strain of toxoplasma ... | 1980 | 7357553 |
| [action of white rat macrophages against toxoplasma gondii in vitro]. | | 1981 | 7348321 |
| characterization of toxoplasma gondii isolates from an outbreak of toxoplasmosis in atlanta, georgia. | toxoplasma gondii was isolated from tissue of 5 of 7 cats and of 4 of 4 field mice trapped in a riding stable in atlanta where an outbreak of toxoplasmosis had occurred in persons. dye-test antibodies were not found in serum of 4 cats and 4 field mice shown to be infected with t gondii by mouse inoculation. the pathogenicity and infectivity of the 9 isolates of t gondii from cats and mice were compared in mice with the same characteristics of an isolate from a person who acquired toxoplasmosis i ... | 1981 | 7283229 |
| intermediate and transport hosts of toxoplasma gondii in costa rica. | toxoplasma gondii was isolated from 3.5% of 202 mus musculus, 12.5% of 120 rattus norvegicus, 16% of 106 sparrows (zonotrichia capensis), and from 54% of 50 chickens from costa rica. the infection rate in chickens increased from 23% in those weighing less than 500 g, to 73% in those between 500 and 1,000 g, indicating a rapid rate of acquiring infectin, probably from the soil in which they constantly search for food. no isolates were made from musca domestica, or from four genera of roaches caug ... | 1980 | 7446807 |
| transmission of toxoplasma gondii in panama city, panama: a five-year prospective cohort study of children, cats, rodents, birds, and soil. | a cohort of more than 500 children from panama city, panama was studied prospectively over five years for acquisition of antibody to toxoplasma gondii. the direct agglutination test showed that 72 of 571 children seroconverted between one and six years of age, for a cumulative incidence of 12.6%. children were examined by pediatricians quarterly, and illnesses that had occurred in the interval and their activities were noted on questionnaires. thirty-eight variables were examined for their role ... | 1995 | 7485703 |
| prevalence of antibodies to toxoplasma gondii in wild mammals of missouri and east central kansas: biologic and ecologic considerations of transmission. | sera from 273 wild mammals from missouri and kansas (usa), collected between december 1974 and december 1987, were tested for the presence of antibodies to toxoplasma gondii using the sabin-feldman dye test. sixty-five (24%) had antibodies at titers of > or = 1:8, including 38 (66%) of 58 carnivores, 14 (15%) of 94 omnivores, 13 (11%) of 117 herbivores, and none of four insectivores. the prevalence of antibodies in mice (mus musculus and peromyscus spp.) and rats (rattus norvegicus and sigmodon ... | 1995 | 7563419 |
| characterization of a dense granule antigen of toxoplasma gondii (gra6) associated to the network of the parasitophorous vacuole. | this work describes the molecular characterization of gra6, a novel toxoplasma gondii dense granule antigen of 32 kda. cdna clones encoding this protein were isolated using a rat serum directed against an hplc fraction enriched in the protein gra5. cross-reactivity between gra5 and gra6 was demonstrated by production of sera against the recombinant gra5 protein. a serum against a recombinant fragment of gra6 which does not react with gra5 allowed the localization of this antigen at the subcellul ... | 1995 | 7637717 |
| structure-activity and structure-selectivity studies on diaminoquinazolines and other inhibitors of pneumocystis carinii and toxoplasma gondii dihydrofolate reductase. | twenty-eight 2,4-diaminopteridines with alkyl and aralkyl groups at the 6- and 7-positions, five 1,3-diamino-7,8,9,10-tetrahydropyrimido [4,5-c]isoquinolines with an alkyl, alkylthio, or aryl group at the 6-position, and nine 4,6-diamino-1,2-dihydro-s-triazines with one or two alkyl groups at the 2-position and a substituted phenyl or naphthyl group at the 1-position were evaluated as inhibitors of dihydrofolate reductase enzymes from pneumocystis carinii, toxoplasma gondii, and rat liver. halog ... | 1995 | 7695334 |
| 6-substituted 2,4-diamino-5-methylpyrido[2,3-d]pyrimidines as inhibitors of dihydrofolate reductases from pneumocystis carinii and toxoplasma gondii and as antitumor agents. | the synthesis and biological activity of 15 6-substituted 2,4-diamino-5-methylpyrido[2,3-d]-pyrimidines are reported. these compounds were synthesized in improved yields by modifications of procedures previously reported by us. specifically, dimethoxyphenyl-substituted compounds with h and ch3 at the n-10 position and trimethoxyphenyl-substituted compounds with n-10 ethyl, isopropyl, and propargyl moieties were synthesized. these compounds were evaluated as inhibitors of dihydrofolate reductases ... | 1995 | 7752201 |
| the effect of toxoplasma gondii and other parasites on activity levels in wild and hybrid rattus norvegicus. | using both correlational and experimental evidence, the relationship between parasite load and host activity was assessed in brown rats, rattus norvegicus. two hypotheses were tested--(1) that parasites with indirect life-cycles, involving transmission between a prey and its predator, will alter the activity of the intermediate host so as to increase its susceptibility to predation by the definitive host and (2) that activity levels in parasitized rats would be increased rather than decreased. f ... | 1994 | 7831094 |
| antigenicity and immunogenicity of p30-derived peptides in experimental models of toxoplasmosis. | p30, also referred to as sag-1, is now recognized as a major toxoplasma gondii antigen potentially important for both diagnosis and immunoprophylaxis of toxoplasmosis. by using predictive algorithms, five synthetic peptides (48-67, 82-102, 213-230, 238-256 and 279-285) derived from p30, were investigated for b- and t-cell determinants in mouse and rat experimental models. antibody recognition appeared more broadly distributed along the p30 sequence, whereas t-cell recognition was mainly targeted ... | 1994 | 7997247 |
| differential development of toxoplasma gondii in neural cells. | in this article, remi fagard and colleagues discuss the properties of neurons that lead to their low infection by toxoplasma gondii, and the role that cytokines such as tumour necrosis factor alpha (tnf-alpha) and interferon gamma (ifn-gamma) might play. | 1999 | 10557153 |
| immunological analyses of antigens associated with experimental toxoplasmosis. | by immunoelectrophoresis of periotoneal exudates and toxoplasma cell antigens from mice and hamsters infected with toxoplasma gondii, using their corresponding rabbit antisera absorbed with serum of uninfected animals, eleven precipitating antigens were distinguished and named no. 1--11 in order of increasing electrophoretic mobility. monospecific rabbit antisera against two of these antigens (antigen no. 1 and 11) were prepared by immunization with antigen purified by zone electrophoresis, and ... | 1980 | 7437003 |
| effect of toxoplasma gondii upon neophobic behaviour in wild brown rats, rattus norvegicus. | the effect of toxoplasma gondii on neophobic behaviour (the avoidance of novel stimuli) was assessed in four groups of wild rats with naturally occurring toxoplasma infection. two groups were placed in individual cages and tested in a series of experiments which examined the effect of toxoplasma on the rat's reaction to 3 food-related novel stimuli (odour, food-container, food). a trappability study was performed on the other two groups to test whether toxoplasma had an effect on probability of ... | 1994 | 8058367 |
| antibodies against toxoplasma in commensal rodents trapped in riyadh region, saudi arabia. | toxoplasma gondii, that protozoal parasite which causes toxoplasmosis, pays no respect to boundaries of zoology and geography. it has been reported in a large number of birds and mammals including man from nearly all over the world. in saudi arabia, the incidence of human infection ranges between 21% and 49.3%. in this paper, the level of antibodies against toxoplasma in sera of different species of rodents was measured by the indirect haemagglutination tests (iha). the seropositivities ranged b ... | 1994 | 8077747 |
| 2,4-diaminothieno[2,3-d]pyrimidine analogues of trimetrexate and piritrexim as potential inhibitors of pneumocystis carinii and toxoplasma gondii dihydrofolate reductase. | a series of eight previously undescribed 2,4-diaminothieno[2,3-d]pyrimidine analogues of the potent dihydrofolate reductase (dhfr) inhibitors trimetrexate (tmq) and piritrexim (ptx) were synthesized as potential drugs against pneumocystis carinii and toxoplasma gondii, which are major causes of severe opportunistic infections in aids patients. 2,4-diamino-5-methyl-6-(aryl/aralkyl)thieno[2,3-d]pyrimidines with 3,4,5-trimethoxy or 2,5-dimethoxy substitution in the aryl/aralkyl moiety and 2,4-diami ... | 1993 | 8230096 |
| toxoplasma gondii: differential location of antigens secreted from encysted bradyzoites. | since we have previously demonstrated the protective role against infection played by toxoplasma excreted-secreted antigens (darcy et al. parasite immunology, 10, 553-567, 1988), the aim of the present work was an attempt to precisely define the location of gra1, gra2, and gra5 in both the tachyzoite and the bradyzoite stages from distinct strains, in order to explore the mechanisms of secretion by toxoplasma gondii. three monoclonal antibodies (charif et al. 1990) and colloidal immunogold label ... | 1993 | 8344403 |
| toxoplasma polymerase chain reaction on experimental blood samples. | a two-stage polymerase chain reaction (pcr) assay employing oligonucleotide primers from the b1 gene of toxoplasma gondii was developed and assessed for sensitivity and specificity. it was able to detect t. gondii dna from as little as one parasite/sample in mock-infected rat or mouse leucocyte preparations. parasitaemia was also identified in animals at five stages between 16 and 66 h after infection with the virulent rh strain, and at 12 stages between 2 and 38 days after infection with the cy ... | 1993 | 8418292 |
| [experimental models of toxoplasmosis. pharmacological applications]. | toxoplasma gondii is an ubiquitous protozoan parasite causing severe or life-threatening infections in immunocompromised patients and in congenitally infected infants. animal models have been extensively used to describe the pathology of infection and to identify new effective drugs for the treatment of congenital infections, chrorioretinitis and toxoplasmic encephalitis. although inherent differences between man and animal can reduce the relevance of data obtained experimentally, animal models ... | 1995 | 8520799 |
| evidence for heterotrimeric gtp-binding proteins in toxoplasma gondii. | toxoplasma gondii, an intracellular protozoan parasite, resides within a host-derived vacuole that is rapidly modified by a parasite-secreted membranous tubular network. in this study we investigated the involvement of heterotrimeric g proteins in the secretory pathway of t. gondii. aluminum fluoride (alfn), a specific activator of heterotrimeric g proteins, induced secretion from isolated tachyzoites of t. gondii in vitro, as seen by light optics and electron microscopy. in western blot analyse ... | 1996 | 8640189 |
| altered trimethoprim-sulfamethoxazole ratios for prophylaxis and treatment of toxoplasma gondii and pneumocystis carinii dual infections in rat model. | trimethoprim-sulfamethoxazole (tmp-smx) is the first-line drug for prophylaxis and treatment of pneumocystis carinii pneumonia (pcp) and for prophylaxis of toxoplasmosis in hiv-infected patients. evidence indicating intolerance related to the dose of smx led us to examine the efficacy of altered tmp-smx ratios in a corticosteroid-treated rat model. infections were assessed by counting p. carinii cysts in lung and by titration of toxoplasma gondii burdens in tissue culture. for prophylaxis, the r ... | 1996 | 8898664 |
| 2-amino-4-oxo-5-substituted-pyrrolo[2,3-d]pyrimidines as nonclassical antifolate inhibitors of thymidylate synthase. | six novel 2-amino-4-oxo-5-[(substituted phenyl)sulfanyl]pyrrolo[2,3-d]pyrimidines 7-12 were synthesized as potential inhibitors of thymidylate synthase (ts) and as antitumor and/or antibacterial agents. the analogues contain a 5-thio substituent with a phenyl, 4'-chlorophenyl, 3',4'-dichlorophenyl, 4'-nitrophenyl, 3',4'-dimethoxyphenyl, and 2'-naphthyl on the sulfur, and were synthesized from the key intermediate 2-(pivaloylamino)-4-oxo-6-methylpyrrolo[2,3-d]-pyrimidine, 17. appropriately substi ... | 1996 | 8917644 |
| synthesis and dihydrofolate reductase inhibitory activities of 2,4-diamino-5-deaza and 2,4-diamino-5,10-dideaza lipophilic antifolates. | two series of nonclassical antifolates (2,4-diamino-5-deaza compounds 2-5 and 5,10-dideaza compounds 6-13) were synthesized as inhibitors of dihydrofolate reductase (dhfr) from pneumocystis carinii (pc) and toxoplasma gondii (tg) organisms that are responsible for fatal opportunistic infections in aids patients. rat liver (rl) dhfr served as the mammalian reference enzyme to determine selectivity. syntheses of the target 5-deaza compounds were achieved by initial construction of the pivaloyl-pro ... | 1997 | 9046337 |
| effect of n9-methylation and bridge atom variation on the activity of 5-substituted 2,4-diaminopyrrolo[2,3-d]pyrimidines against dihydrofolate reductases from pneumocystis carinii and toxoplasma gondii. | the effect of n9-methylation and bridge atom variation on inhibitory potency and selectivity of 2,4-diaminopyrrolo[2,3-d]pyrimidines against dihydrofolate reductases (dhfr) was studied. specifically three nonclassical 2,4-diamino-5-((n-methylanilino)methyl)pyrrolo[2,3-d]pyrimidines with 2',5'-dimethoxyphenyl (2), 3',4'-dichlorophenyl (3), 1'-naphthyl (4), one classical analogue with a 4'-l-glutamate substituent (10), and four nonclassical 2,4-diamino-5-((phenylthio)methyl)pyrrolo[2,3-d]pyrimidin ... | 1997 | 9089339 |
| suppression of unprimed t and b cells in antibody responses by irradiation-resistant and plastic-adherent suppressor cells in toxoplasma gondii-infected mice. | in the acute phase of toxoplasma infection, the function of both helper t and b cells was suppressed in primary antibody responses to dinitrophenol (dnp)-conjugated protein antigens. during the course of infection, the suppressive effect on t cells seems to continue longer than that on b cells, since suppression in responses to sheep erythrocytes, a t-dependent antigen, persisted longer than those to dnp-ficoll, a t-independent antigen. plastic-adherent cells from the spleens of toxoplasma-infec ... | 1983 | 6219954 |
| toxoplasmosis in rats (rattus norvegicus): congenital transmission to first and second generation offspring and isolation of toxoplasma gondii from seronegative rats. | to study congenital transmission of toxoplasma gondii during acute and chronic infections, 4 pregnant sprague-dawley rats were each fed 10,000 oocysts of the veg strain. toxoplasma gondii was recovered from 33, 55, 83 and 57% of rats (f1) when dams were inoculated at 6, 9, 12 or 15 days of gestation, respectively. progeny of 15 congenitally infected female rats were examined for t. gondii. toxoplasma gondii was recovered from tissues of 1 of 155 rats (f2) born to congenitally infected dams. a to ... | 1997 | 9226952 |
| toxoplasma gondii (eucoccidia: sarcoystidae) dissemination pattern in rats after oral infection with oocysts of an avirulent strain. | differences in toxoplasma gondii dissemination in white rats (sprague dowley) and mice (wistar) after oral oocyst inoculation are described. groups of five animals (both hosts) were infected per os with oocysts of the tcr-2 avirulent strain and the dissemination pattern was compared in brain tissue or by serology. early dissemination was similar in both species. one hr after infection the parasite was present in blood and peritoneal exudate as well as in heart, lung, liver, spleen, lymph nodes a ... | 1997 | 9404517 |
| neurons in primary culture are less efficiently infected by toxoplasma gondii than glial cells. | infection by toxoplasma gondii is asymptomatic, leading to an immune response that controls the disease. in immune-compromised patients, however, quiescent cysts can reactivate, leading to toxoplasmic encephalitis. we studied the infection of cells of the central nervous system in an attempt to understand the process leading to this complication. primary cultures of rat hippocampal glial cells and neurons were infected with the virulent strain rh and examined by immunofluorescent microscopy afte ... | 1998 | 9491422 |
| synthesis and biological activities of tricyclic conformationally restricted tetrahydropyrido annulated furo[2,3-d]pyrimidines as inhibitors of dihydrofolate reductases. | the synthesis of seven 2,4-diamino-5,6,7,8-tetrahydro-7-substituted pyrido[4',3':4,5]furo[2,3-d]pyrimidines 1-6 are reported as nonclassical antifolate inhibitors of dihydrofolate reductase (dhfr) and compound 7 as a classical antifolate inhibitor of tumor cells in culture. the compounds were designed as conformationally restricted analogues of trimetrexate. the synthesis was accomplished from the cyclocondensation of 3-bromo-4-piperidone with 2, 4-diamino-6-hydroxypyrimidine to afford regiospec ... | 1998 | 9554874 |
| tissue culture and explant approaches to studying and visualizing neospora caninum and its interactions with the host cell. | neospora caninum is an apicomplexan parasite first mentioned in 1984 as a causative agent of neuromuscular disease in dogs. it is closely related to toxoplasma gondii and hammondia heydorni, and its subsequent description in 1988 has been, and still is, accompanied by discussions on the true phylogenetical status of the genus neospora. n. caninum exhibits features that clearly distinguish this parasite from other members of the apicomplexa, including distinct ultrastructural properties, genetic ... | 2004 | 15525434 |
| drug evaluation of concurrent pneumocystis carinii, toxoplasma gondii, and mycobacterium avium complex infections in a rat model. | we present a new experimental model for the simultaneous evaluation of the activities of drugs against pneumocystis carinii, toxoplasma gondii, and mycobacterium avium complex infections. rats latently infected with p. carinii were challenged with the mo-1 strain of m. avium and then immunosuppressed with corticosteroids for 7 weeks. at week 5 the rh strain of t. gondii was intraperitoneally injected. organs were examined for the three pathogens after death or killing of the animals at week 7. w ... | 1998 | 9593128 |
| the prevalence of neospora caninum and co-infection with toxoplasma gondii by pcr analysis in naturally occurring mammal populations. | neospora caninum and toxoplasma gondii are closely related intracellular protozoan parasites associated with bovine and ovine abortion respectively. little is known about the extent of neospora/toxoplasma co-infection in naturally infected populations of animals. using nested pcr techniques, based on primers from the nc5 region of n. caninum and sag1 for t. gondii, the prevalence of n. caninum and its co-infection with t. gondii were investigated in populations of mus domesticus, rattus norvegic ... | 2006 | 16393351 |
| toxoplasmosis of rats: a review, with considerations of their value as an animal model and their possible role in epidemiology. | we critically review and summarize information on the prevalence of toxoplasma gondii infections in rats, mainly rattus norvegicus, and their possible role as a source of infection for larger carnivores and omnivores. we also review information on immunology and natural resistance, contributing to the model value of rats in the analysis of human infection. rats can be successfully infected with oocysts (sporozoites), tissue cysts (bradyzoites), and tachyzoites. even adult rats, that are resistan ... | 1998 | 9652380 |
| prevalence and transmission of toxoplasma gondii in wild brown rats, rattus norvegicus. | prevalence of toxoplasma gondii within 6 uk farmstead wild rat populations, and 1 population maintained within a captive cat-free environment for 2.5 years, was examined. the mean prevalence found was 35% (n = 235), which is more than 3 times as high as all other wild rat prevalence levels previously reported in the uk. there were no significant age, sex or site differences in prevalence between or within populations irrespective of habitat type or presence of cats. toxoplasma was also maintaine ... | 1994 | 8008454 |
| experimental congenital toxoplasmosis in wistar and holtzman rats. | congenital toxoplasmosis was evaluated in wistar and holtzman rats using two strains of toxoplasma gondii isolated in brazil. pregnant rats were inoculated by subcutaneous or intraperitoneal routes with 10(6) or 8 x 10(6) tachyzoites of n strain (virulent for mice) and by subcutaneous or oral routes with 10(2) or 1.2 x 10(3) cysts of p strain (avirulent for mice). the tissues of rat pups born from these rats were bioassayed for t. gondii infection. t. gondii was not observed in the pups born fro ... | 1999 | 10229939 |
| proteomics in human disease: cancer, heart and infectious diseases. | in recent years, genomics has increased the understanding of many diseases. proteomics is a rapidly growing research area that encompasses both genetic and environmental factors. the protein composition represents the functional status of a biological compartment. the five approaches presented here resulted in the detection of disease-associated proteins. calgranulin b was upregulated in colorectal cancer, and hepatoma-derived aldose reductase-like protein was reexpressed in a rat model during h ... | 1999 | 10451122 |
| cell-culture system for continuous production of toxoplasma gondii tachyzoites. | the aim of this study was to identify a sustainable cell line and culture method that could continuously provide a sufficient quantity of toxoplasma gondii tachyzoites to serve the needs of a general hospital laboratory. three continuous cell lines (hela, llc and vero) and three cell-culture methods (culture in conventional flasks, culture in membrane-based flasks and an automated culture system) were investigated. in multiplicity-of-infection and time-course experiments, hela was the cell line ... | 1999 | 10691199 |
| infection of white rat peritoneal macrophages with toxoplasma gondii, (coccidia: sarcocystidae) after trypanosoma lewisi (kinetoplastida: trypanosomatidae) infection. | peritoneal macrophages from wistar rats, inoculated and non-inoculated with 10(6) t. lewisi trypomastigotes, were cultured and infected with 10(6) t. gondii tachyzoites. multiplication rates of this parasite were studied after 1, 24 and 48 h of infection but there were not significant differences between the number of parasites found inside of macrophages coming, either from t. lewisi infected or non infected rats. on the other hand, in vivo studies of toxoplasma multiplication inside peritoneal ... | 1999 | 10883328 |
| parasite-altered behaviour: is the effect of toxoplasma gondii on rattus norvegicus specific? | the effect of toxoplasma gondii on rat behaviour was assessed in a colony of 36 free-ranging wild/laboratory hybrid rats allowed to compete freely for food and mates in a (100 m2) outdoor naturalistic enclosure. t. gondii infection had no effect on social status or mating success, both the product of costly and competitive activities. however, the propensity to explore novel stimuli in their environment was higher in infected than uninfected individuals. these results are consistent with the hyp ... | 1995 | 11023404 |
| improved methods for examination of toxoplasma gondii cytoskeleton at ultrastructural level. | to evaluate an improved method for identifying the presence of the structural elements of the cytoskeleton of toxoplasma gondii and their influence on invasion of the parasite in host cells, copper grids coated with plastic film were used for adhesion of whole parasites. tachyzoites were incubated with 0.5% triton x-100 in phem buffer containing protease inhibitors, post-fixed in 1% glutaraldehyde, stained with uranyl acetate and submitted to critical point drying. in order to analyze the presen ... | 2001 | 11355677 |
| synthesis, antifolate, and antitumor activities of classical and nonclassical 2-amino-4-oxo-5-substituted-pyrrolo[2,3-d]pyrimidines. | classical and nonclassical isosteric c8-n9 bridged analogues of the multitargeted antifolate ly231514 were synthesized as inhibitors of thymidylate synthase (ts), dihydrofolate reductase (dhfr), and as antitumor and antiopportunistic infection agents. the syntheses of the analogues were accomplished by reductive amination of the appropriate anilines with 2-amino-4-oxo-5-cyanopyrrolo[2,3-d]pyrimidine (28) followed by saponification of the ethyl esters, for the classical analogue 6. the n9-methyl ... | 2001 | 11384244 |
| synthesis of 2,4-diamino-6-(thioarylmethyl)pyrido[2,3-d]pyrimidines as dihydrofolate reductase inhibitors. | six 2,4-diaminopyrido[2,3-d]pyrimidines with a 6-methylthio bridge to an aryl group were synthesized and biologically evaluated as inhibitors of pneumocystis carinii (pc) and toxoplasma gondii (tg) dihydrofolate reductase (dhfr). the syntheses of analogues 3-8 were achieved by nucleophilic displacement of 2,4-diamino-6-bromomethylpyrido[2,3-d]pyrimidine 14 with various arylthiols. the alpha-naphthyl analogue 4 showed the highest selectivity ratios of 3.6 and 8.7 against pcdhfr and tgdhfr, respec ... | 2001 | 11597474 |
| activation of rat alveolar macrophages by gamma interferon to inhibit toxoplasma gondii in vitro. | we have investigated the effects of murine interferons on the ability of rat alveolar macrophages (am) to inhibit the proliferation of the intracellular protozoan toxoplasma gondii. this activity was determined by measuring suppression of 3h-uracil uptake into the toxoplasma and by microscopic enumeration of the intracellular organisms. recombinant gamma interferon (rmulfn-gamma), but not alpha/beta interferon (ifn-alpha/beta) was able to activate am for antimicrobial activity in vitro. maximum ... | 1987 | 2824644 |
| [cellular interactions in the intracellular parasitism of cryptosporidia. i. the effect of cryptosporidium parvum on the phosphatase activity in the small intestine enterocytes of experimentally infected newborn rat pups]. | cytochemical methods for detection of non-specific phosphatases were employed at the light microscope level for identification of enzymatic activity in the small intestine of new-born rats (6--11 days old), both infected and non-infected with the intestinal coccidium cryptosporidium parvum. in the new-born rats, the level of alkaline and especially acid phosphatase is originally very low, suggesting their insignificant involvement in digestion processes in suckling animals compared to rats of ol ... | 1995 | 8669134 |
| age influence in the natural resistance of white rat and mice to the protozoan toxoplasma gondii. | groups of 1, 5, 10, 15 and 30 day old rats (sprague dawley) and wistar mice were infected per os with different inocula of toxoplasma gondii oocysts from an avirulent strain. infection pattern was followed by determination of survival time, tissue lesions, parasite presence and serology. although all the animals survived the total experimental period (30 day), there were important differences between both rodents regarding to toxoplasma natural resistance. brain cysts, as well as tachyzoites in ... | 1995 | 8728756 |
| [in vitro effect of (+)-usnic acid on toxoplasma gondii tachyzoites]. | to explore the effect of usnic acid on toxoplasma gondii tachyzoites in vitro. | 2008 | 19288918 |
| identification of a class of sulfonamides highly active against dihydropteroate synthase form toxoplasma gondii, pneumocystis carinii, and mycobacterium avium. | sulfanilanilides with 3',5'-halogen substitutions had ki values 6- to 57-fold lower than the ki of sulfamethoxazole when tested against dihydropteroate synthase from toxoplasma gondii. the compounds acted as competitive inhibitors. these compounds were also active against dihydropteroate synthase from pneumocystis carinii, mycobacterium avium, and escherichia coli but were not significantly more active than sulfamethoxazole. the compounds were significantly more active in culture than were stand ... | 1996 | 8851601 |
| [analysis of trace elements in liver, spleen and brain of rats infected with toxoplasma gondii]. | to study the level of five trace elements(fe2+, cu2+, zn2+, ca2+, mg2+) in the liver, spleen and brain of the rats infected with toxoplasma gondii. | 2000 | 12567611 |
| [electrophoretic studies on rat sera after latent toxoplasma gondii infection]. | | 1958 | 13558320 |
| serosurvey for canine distemper virus, canine adenovirus, leptospira interrogans, and toxoplasma gondii in free-ranging canids in scandinavia and svalbard. | prevalence of antibodies reactive to canine distemper virus (cdv), canine adenovirus type 1 (cav-1), leptospira interrogans serovars canicola and icterohaemorrhagiae, and toxoplasma gondii were examined in free-ranging scandinavian canids. sampling included 275 red foxes (vulpes vulpes) from mainland norway, 60 arctic foxes (vulpes lagopus) from the high-arctic islands of svalbard, and 98 wolves (canis lupus) from the joint swedish-norwegian population. methods used included virus neutralization ... | 2010 | 20688639 |
| efficacy of azithromycin in a murine toxoplasmosis model, employing a toxoplasma gondii strain from turkey. | a murine toxoplasmosis model with balb/c mice was used to investigate the therapeutic and prophylactic efficacy of azithromycin in a native strain of toxoplasma gondii. initially, seven groups--four studies and three controls--were established and 10(3) tachyzoites of this native strain of t. gondii were injected intraperitoneally to the mice in groups 1, 2, 3, 4 and 7. azithromycin was given to groups 1-4 at different times of infection orally between 100 and 300 mg/kg/day for 10 days. azithrom ... | 2003 | 12943976 |
| inhibition of pneumocystis carinii, toxoplasma gondii, and mycobacterium avium dihydrofolate reductases by 2,4-diamino-5-[2-methoxy-5-(omega-carboxyalkyloxy)benzyl]pyrimidines: marked improvement in potency relative to trimethoprim and species selectivity relative to piritrexim. | a series of previously undescribed 2,4-diamino-5-[2-methoxy-5-alkoxybenzyl]pyrimidines (3a-e) and 2,4-diamino-5-[2-methoxy-5-(omega-carboxyalkyloxy)benzyl]pyrimidines (3f-k) with up to eight ch2 groups in the alkoxy or omega-carboxyalkyloxy side chain were synthesized and tested for the ability to inhibit partially purified dihydrofolate reductase (dhfr) from pneumocystis carinii (pc), toxoplasma gondii (tg), mycobacterium avium (ma), and rat liver in comparison with two standard inhibitors, tri ... | 2002 | 11754594 |
| seroprevalence of toxoplasma gondii in rats in southern china. | toxoplasma gondii is widely distributed in humans and other animals, including wild rats throughout the world, but little is known of the prevalence of t. gondii in rats in china. the seroprevalence of t. gondii in rats ( rattus norvegicus and rattus flavipectus ) was investigated in guangzhou, southern china, between november 2009 and january 2010. in total, 217 rat serum samples were collected; antibodies to t. gondii were detected by the modified agglutination test (mat), and 7 (3.2%) were fo ... | 2010 | 21158644 |
| effect of bronchoalveolar lavage fluid from pneumocystis carinii-infected hosts on phagocytic activity of alveolar macrophages. | alveolar macrophages from pneumocystis carinii-infected rats are defective in phagocytosis. to investigate whether this defect is due to a certain factor present in p. carinii-infected lungs, alveolar macrophages from uninfected rats were incubated with bronchoalveolar lavage (bal) fluid samples from p. carinii-infected rats. alveolar macrophages treated with these bal fluid samples became defective in phagocytosis but remained normal when treated with bal fluid samples from noninfected or toxop ... | 2004 | 15039336 |
| synthesis of 2,4-diamino-6-[2'-o-(omega-carboxyalkyl)oxydibenz[b,f]azepin-5-yl]methylpteridines as potent and selective inhibitors of pneumocystis carinii, toxoplasma gondii, and mycobacterium avium dihydrofolate reductase. | six previously undescribed n-(2,4-diaminopteridin-6-yl)methyldibenz[b,f]azepines with water-solubilizing o-carboxyalkyloxy or o-carboxybenzyloxy side chains at the 2'-position were synthesized and compared with trimethoprim (tmp) and piritrexim (ptx) as inhibitors of dihydrofolate reductase (dhfr) from pneumocystis carinii (pc), toxoplasma gondii (tg), and mycobacterium avium (ma), three of the opportunistic organisms known to cause significant morbidity and mortality in patients with aids and o ... | 2004 | 15115391 |
| seroepidemiology of toxoplasma gondii, neospora caninum, and leishmania spp. infections and risk factors for cats from brazil. | the seroprevalence of infection by toxoplasma gondii, neospora caninum, and leishmania spp. was detected through an indirect immunofluorescence in 70 cats from the andradina municipality, são paulo state, brazil. anti-t. gondii antibodies (titer >64) were detected in 15.7% (11/70) of animals, whereas positivity for n. caninum (titer 16) was not observed in any animal. of the cats from urban and rural areas, 10.4% (5/48) and 27.2% (6/22) were positive for t. gondii, respectively. breed, age, food ... | 2011 | 21626423 |
| a survey of neospora caninum and toxoplasma gondii infection in urban rodents from brazil. | abstract toxoplasma gondii is a protozoan parasite that infects humans and other warm blooded animals; it uses feral and domestic cats as the definitive hosts. neospora caninum is a protozoan parasite of animals whose life cycle is very similar to t. gondii, but uses canids as definitive hosts. small rodents play an important role in the life cycle of t. gondii and a few findings indicated that they may be natural intermediate hosts for n. caninum. the present study was aimed at identifying infe ... | 2011 | 21790367 |
| design, synthesis, and biological evaluation of 2,4-diamino-5-methyl-6-substituted-pyrrolo[2,3-d]pyrimidines as dihydrofolate reductase inhibitors. | 2,4-diamino-5-methyl-6-(substituted-phenyl)thiopyrrolo[2,3-d]pyrimidines 4-11 were synthesized as dihydrofolate reductase (dhfr) inhibitors against opportunistic pathogens that afflict patients with aids. synthesis was achieved from 2,4-diamino-5-methypyrrolo[2,3-d]pyrimidine and substituted phenylthiols under modified conditions reported by gangjee et al. some of these compounds were potent and selective against dhfr from both toxoplasma gondii and mycobacterium avium compared to mammalian dhfr ... | 2004 | 15214795 |
| differential effects of interferon-gamma and tumor necrosis factor-alpha on toxoplasma gondii proliferation in organotypic rat brain slice cultures. | organotypic slice culture explants of rat cortical tissue infected with toxoplasma gondii tachyzoites were applied as an in vitro model to investigate host-pathogen interactions in cerebral toxoplasmosis. the kinetics of parasite proliferation and the effects of interferon-gamma (ifn-gamma) and tumor necrosis factor-alpha (tnf-alpha) in infected organotypic cultures were monitored by light microscopy, transmission electron microscopy (tem), and quantitative polymerase chain reaction (pcr) assay. ... | 2005 | 15986605 |
| serologic detection of toxoplasma gondii infection in rattus spp collected from three different sites in dasmariñas, cavite, philippines. | acute and chronic cases of toxoplasmosis in rattus norvegicus and rattus rattus mindanensis caught in agricultural, commercial and residential sites in dasmariñas, cavite, philippines were determined serologically. fifty-eight percent of r. norvegicus and 42.0% of r. r. mindanensis were positive for anti-t. gondii antibodies (abs). infection was higher in male rats, and those caught in the commercial site had 100.0% seropositivity. thirty percent of the r. norvegicus and 51.0% r. rattus mindanen ... | 2005 | 16438179 |
| globalization and the population structure of toxoplasma gondii. | toxoplasma gondii is a protozoan parasite that infects nearly all mammal and bird species worldwide. usually asymptomatic, toxoplasmosis can be severe and even fatal to many hosts, including people. elucidating the contribution of genetic variation among parasites to patterns of disease transmission and manifestations has been the goal of many studies. focusing on the geographic component of this variation, we show that most genotypes are locale-specific, but some are found across continents and ... | 2006 | 16849431 |
| prevalence of toxoplasma gondii in rats (rattus norvegicus) in grenada, west indies. | cats are important in the natural epidemiology of toxoplasma gondii, because they are the only hosts that can excrete environmentally resistant oocysts. cats are infected with t. gondii via predation on infected birds and rodents. during 2005, 238 rats (rattus norvegicus) were trapped in grenada, west indies, and their sera along with tissue samples from their hearts and brains were examined for t. gondii infection. antibodies to t. gondii were assayed by the modified agglutination test (mat, ti ... | 2006 | 17152961 |
| design and synthesis of classical and nonclassical 6-arylthio-2,4-diamino-5-ethylpyrrolo[2,3-d]pyrimidines as antifolates. | the classical antifolate n-{4-[(2,4-diamino-5-ethyl-7h-pyrrolo[2,3-d]pyrimidin-6-yl)sulfanyl]benzoyl}-l-glutamic acid (2) and 15 nonclassical analogues (3-17) were synthesized as potential dihydrofolate reductase (dhfr) inhibitors and as antitumor agents. 5-ethyl-7h-pyrrolo[2,3-d]pyrimidine-2,4-diamine (20) served as the key intermediate to which various aryl thiols and a heteroaryl thiol were appended at the 6-position via an oxidative addition reaction. the classical analogue 2 was synthesized ... | 2007 | 17552508 |
| evolution: parasites make scaredy-rats foolhardy. | in the 7 august issue of the proceedings of the royal society of london b, researchers offer a striking demonstration of the ability of some parasites to alter the behavior of their hosts for their own benefit. rats, the intermediate hosts of the protozoan toxoplasma gondii, appear to lose their fear of cats, toxoplasma's final host, when the parasite infects them. by precisely altering rat brains, the parasite potentially increases its chances of completing its life cycle. | 2000 | 17832058 |
| effect of melatonin and zinc on the immune response in experimental toxoplasma retinochoroiditis. | to investigate the possible effect of melatonin (mel) and zinc on the immune response to toxoplasma gondii retinochoroiditis in the rat model of infection and to establish the possible value of artificial mel and/or zinc supplementation as adjunctive therapeutic agents in the treatment of t. gondii retinochoroiditis. | 2007 | 17947831 |
| [determination of t lymphocytes and trace elements in spleen from rats infected with toxoplasma gondii]. | to determine the level of five trace elements(fe2+, cu2+, zn2+, ca2+, mg2+) in the spleen and changes of t lymphocyte and its subtype variations in peripheral blood from the rats infected with toxoplasma gondii. | 2001 | 12572072 |
| different manifestations of toxoplasma gondii infection in f344 and lew rats. | there is evidence that not only the immune status, but also the genetic predisposition of certain hosts influence the clinical outcome of toxoplasma gondii infection. by far the majority of our knowledge on genetic and immunological mechanisms involved in control of t. gondii infection has been obtained by studying mouse models, which in terms of clinical outcome of infection differ considerably from humans. rats which show a rather similar course of infection in comparison to humans have not so ... | 1999 | 10206144 |
| the role of rodents and shrews in the transmission of toxoplasma gondii to pigs. | inadequate rodent control is considered to play a role in toxoplasma gondii infection of pigs. this issue was addressed in the current study by combining a 4-month rodent control campaign and a 7-month longitudinal analysis of t. gondii seroprevalence in slaughter pigs. three organic pig farms with known rodent infestation were included in the study. on these farms, presence of t. gondii in trapped rodents was evaluated by real-time pcr. all rodent species and shrews investigated had t. gondii d ... | 2008 | 18606498 |
| specificity of the toxoplasma gondii-altered behaviour to definitive versus non-definitive host predation risk. | the hypothesis that the parasite toxoplasma gondii manipulates the behaviour of its intermediate rat host in order to increase its chance of being predated specifically by its feline definitive host, rather than a non-definitive host predator species, was tested. the impact of a range of therapeutic drugs, previously demonstrated to be effective in preventing the development of t. gondii-associated behavioural and cognitive alterations in rats, on definitive-host predator specificity was also te ... | 2008 | 18620624 |
| toxoplasma gondii: an improved rat model of congenital infection. | the objective of this study was to refine the rat model of congenital toxoplasmosis. in fischer rats we found that visualization of spermatozoa in vaginal exudates and the detection of at least 6g body weight increase between days 9 and 12 of pregnancy, allowed the diagnosis and timing of pregnancy with 60% specificity and 84% sensitivity. a dose of 10(4) toxoplasma gondii bradyzoites or 10(2) t. gondii oocysts of the prugniaud strain resulted in more than 50% of congenital infection of the rat ... | 2008 | 18634785 |
| n9-substituted 2,4-diaminoquinazolines: synthesis and biological evaluation of lipophilic inhibitors of pneumocystis carinii and toxoplasma gondii dihydrofolate reductase. | n9-substituted 2,4-diaminoquinazolines were synthesized and evaluated as inhibitors of pneumocystis carinii (pc) and toxoplasma gondii (tg) dihydrofolate reductase (dhfr). reduction of commercially available 2,4-diamino-6-nitroquinazoline 14 with raney nickel afforded 2,4,6-triaminoquinazoline 15. reductive amination of 15 with the appropriate benzaldehydes or naphthaldehydes, followed by n9-alkylation, afforded the target compounds 5- 13. in the 2,5-dimethoxybenzylamino substituted quinazoline ... | 2008 | 18771252 |
| detection of iga and low-avidity igg antibodies for the diagnosis of recent active toxoplasmosis. | objective: to determine the clinical value of testing iga and the avidity of igg (by two commercial systems) for the detection of recent active toxoplasmosis (rat), and to study the igg avidity during the course of infection. methods: the iga was tested by a capture elisa (pasteur, france) and the avidity of igg was determined by two modified commercial indirect elisa methods (sorin, italy; behringwerke, germany) in 12 patients who were not immunosuppressed (group i) and 57 healthy subjects with ... | 1997 | 11864209 |