| agitated mass cultivation of naegleria fowleri. | | 1977 | 21233 |
| some further characteristics of the growth of naegleria fowleri and n. gruberi in axenic culture. | the effects of ph, various viscosity of the medium, changed ratio between the concentrations of dissolved and corpuscular components in the medium, and dissolved inorganic salts on the growth of axenic cultures of naegleria fowleri and n. gruberi have been studied. the cultures were grown in liquid calyg and bcs media. the ph optimum was 6.5 for n. fowleri and 6.0--6.5 for n. gruberi. no negative influence on the growth of n. fowleri was observed even at 0.5% concentration of highly viscous meth ... | 1978 | 25227 |
| cell and mitochondria respiration of naegleria fowleri. | | 1979 | 41892 |
| growth inhibition of naegleria fowleri by tetracycline, rifamycin, and miconazole. | | 1977 | 72223 |
| ultrastructural observations of experimental naegleria meningoencephalitis in mice: intranuclear inclusions in amebae and host cells. | primary amebic meningoencephalitis was experimentallly produced in mice through intranasal instillation of pathogenic naegleria fowleri. experimental animals had a 64% mortality with average time of onset of symtoms of death occurring on the 7-8th day following inoculation. ultrastructural studies of the olfactory lobes from brains of dead (or sacrificed) animals revealed major concentrations of amebae in the perivascular regions; amebae were also seen to be under attack by host polymorphonuclea ... | 1977 | 202704 |
| a radioimmunoassay for human antibody specific for microbial antigens. | a simple and sensitive method for detecting and quantitating antibody specific for microbial antigens is described. bacterial, fungal, parasitic or viral antigens attached to bromoacetyl cellulose or the intact cells themselves were added to a series of two-fold dilutions of human serum. after a short incubation period, which allowed human antibody to attach to the antigens, the complex was thoroughly washed and carbon-14 labeled anti-human light chain antibody was added to each dilution. the re ... | 1977 | 320268 |
| quantitation and cell size of naegleria fowleri by electronic particle counting. | | 1977 | 321738 |
| observations by immunofluorescence microscopy and electron microscopy on the cytopathogenicity of naegleria fowleri in mouse embryo-cell cultures. | the destruction of secondary mouse-embryo (me) cells by naegleria fowleri was studied by indirect immunofluorescence with me-cell antiserum as a specific label to trace the fate of mammalian-cell cytoplasm. the appearance of naegleria-induced cytopathic effect in the cultures coincided with the accumulation of discrete particles containing granules of me-cell antigen within the cytoplasm of amoebae, suggesting that the organisms ingested host-cell material. in cultures containing cytochalasin b, ... | 1979 | 381667 |
| differences in virulence of naegleria fowleri. | all pathogenic naegleria fowleri isolated from the environment were highly virulent to mice when instilled intranasally. axenic cultivation gradually decreased virulence of highly virulent strains. this decrease was most pronounced in environmental isolates and of minor importance in n. fowleri isolated from human cerebrospinal fluid. the low virulent strains obtained by continuous axenic cultivation appeared after clonation to consist of individuals with different virulence. virulence could be ... | 1979 | 392414 |
| changes in the virulence of naegleria fowleri maintained in vitro. | | 1977 | 410913 |
| recovery of soil amebas from the nasal passages of children during the dusty harmattan period in zaria. | following a fatal case of primary amebic meningoencephalitis during the dusty harmattan period in an 8-month-old child in whose case naegleria fowleri was recovered both from the cerebrospinal fluid and from material from the nose in absence of a history of swimming, it was hypothesized that dust during the harmattan might harbor amebic cysts, which may be inhaled by human beings and cause infection. a preliminary survey was thus carried out to examine the nasal passages of children for the pres ... | 1979 | 425935 |
| a case of primary amebic meningoencephalitis in zaria, nigeria. | a case of primary amebic meningoencephalitis due to naegleria fowleri in a nigerian child is described. this is probably the first authentic case from west africa. the clinical manifestations, isolation of the ameba from the cerebrospinal fluid and nasal passages, poor response to amphotericin b, and ultimate fatal outcome all are consistent with the diagnosis of primary amebic meningoencephalitis. subsequent identification based on morphologic features, flagellation, animal pathogenicity, and n ... | 1979 | 453078 |
| inhibition by amoeba-specific antiserum and by cytochalasin b of the cytopathogenicity of naegleria fowleri in mouse embryo-cell cultures. | inhibitors of trophozoite motility and phagocytosis were used to investigate the mechanism of naegleria fowleri cytopathogenicity in mouse-embryo (me)-cell cultures. amoebae that were immobilised and agglutinated by specific antiserum exhibited no cytopathic activity, although they remained alive and were in constant contact with the me cells. mammalian-cell damage occurred only when the organisms recovered pseudopodium function and began to migrate over the monolayers as they overcame the inhib ... | 1979 | 469930 |
| in vitro susceptibilities of naegleria fowleri strain hb-1 to selected antimicrobial agents, singly and in combination. | the overall prognosis of primary amoebic meningoencephalitis remains poor. the results of this study support previous finding that amphotericin b is the most efficacious drug against the naegleria species in in vitro testing. in addition, the methyl ester of amphotericin b, a new derivative, also appears to be an effective agent. of the drug combinations studied, amphotericin b plus minocycline and amphotericin b plus tetracycline showed synergy. the clinical significance of these findings remai ... | 1979 | 485131 |
| primary amebic meningoencephalitis. | primary amebic meningoencephalitis a rapidly fatal cns infection caused by the free-living ameba naegleria fowleri. the disease is acquired by swimming in fresh water and is being recognized with increasing frequency. results of early diagnosis and treatment with amphotericin and other drugs suggest therapeutic optimism. epidemiological surveys have shown the organism to be commonly present in fresh-water lakes in the warmer parts of the world. prompt recognition and treatment is vital. | 1979 | 495593 |
| susceptibility of naegleria fowleri to delta 9-tetrahydrocannabinol. | growth of the pathogenic amoeboflagellate naegleria fowleri is inhibited by delta 9-tetrahydrocannabinol (delta 9-thc). delta 9-thc is amoebostatic at 5 to 50 micrograms/ml. delta 9-thc prevents enflagellation and encystment, but does not impair amoeboid movement. calf serum at 10 and 20% (vol/vol) reduces the antiamoeba activity of delta 9-thc. only 1-methoxy delta 8-tetrahydrocannabinol, of 17 cannabinoids tested, failed to inhibit growth of n. fowleri. antinaeglerial activity was not markedly ... | 1979 | 526010 |
| immunization with culture supernatant in experimental amoebic meningoencephalitis. | mice were immunized with 0.25 ml culture supernatant intraperitoneally and challenged with 5 x 10(4) naegleria fowleri intranasally. survival rate was 11% after one and 25% after three immunizing doses, compared to 0% in controls. | 1979 | 538810 |
| antibody induced capping and endocytosis of surface antigens in naegleria fowleri. | | 1979 | 541172 |
| starch gel electrophoresis: an effective method for separation of pathogenic and nonpathogenic naegleria strains. | isoenzyme electrophoresis of 7 different enzyme systems was used to compare 24 strains of naegleria fowleri and 6 strains of n. gruberi. the 30 strains could be grouped into 4 distinct categories based upon zymogram patterns. no interstrain band variation in all enzyme systems was demonstrated in pathogenic strains of n. fowleri. three nonpathogenic high temperature-tolerant strains of naegleria had similar zymograms. four of the 5 remaining nonpathogenic naegleria strains had no interstrain ban ... | 1979 | 544800 |
| naegleria fowleri in the chick embryo. | | 1979 | 555075 |
| naegleria fowleri in chick embryos. effects of embryo age and incubation temperature, and the infectivity of embryo-derived amebae for mice. | chick embryos were infected with naegleria fowleri which was initially isolated from an ultimately fatal human case. following inoculation of equivalent numbers of amebae on the chorioallantoic membrane, younger embryos died earlier than older embryos infected at the same time. incubation of infected embryos at 32 degrees c prolonged survival only slightly in comparison with those at 37 degrees c. n. fowleri maintained for more than 25 serial passages in chick embryos retained infectivity for mi ... | 1979 | 574367 |
| isolation of the etiological agent of primary amoebic meningoencephalitis from artifically heated waters. | to determine whether artificial heating of water by power plant discharges facilitates proliferation of the pathogenic free-living amoebae that cause primary amoebic meningoencephalitis, water samples (250 ml) were taken from discharges within 3,000 feet (ca. 914.4 m) of power plants and were processed for amoeba culture. pathogenic naegleria fowleri grew out of water samples from two of five lakes and rivers in florida and from one of eight man-made lakes in texas. pathogenic n. fowleri did not ... | 1977 | 596872 |
| detection of antibody against limax amoebae by means of the indirect haemagglutination test. | a detailed description is given of the procuedure of the indirect haemagglutination test employed in the detection of specific antibodies against pathogenic amoebae of the genera naegleria and acanthamoeba. the preservation of all ingredients obtained by lyophilisation provide for a standard pattern of the test. the results of the test with experimentally prepared immune rabbit sera demonstrate an antigenic uniformity of the various isolates of naegleria fowleri, and their marked difference from ... | 1977 | 604214 |
| [amoebic meningoencephalitis by "eaegleria" and "acanthamoeba" (author's transl)]. | primary amoebic meningoencephalitis (me) by naegleria fowleri a free-living protozoon found in fresh, warm waters, is a well known fatal disease lasting less than one week. it affects sporadically swimmers and children playing in mud puddles. less than 100 cases have been described. recently a more rare, distinct amoebic meningoencephalitis due to some species of free-living acanthamoeba was identified, lasting some weeks or more but still with a fatal evolution. in this case the amoebae do not ... | 1977 | 616244 |
| protective immunity to naegleria fowleri in experimental amebic meningoencephalitis. | naegleria fowleri, a free-living ameboflagellate, is the causative organism of primary amebic meningoencephalitis. intranasal inoculation of n. fowleri in mice produces an infection similar to human disease. mice immunized with live n. fowleri by intraperitoneal injection were found to be more resistant to subsequent intranasal challenge. these results may provide a lead to the development of immunotherapy for this virulent disease for which satisfactory chemotherapy is presently unavailable. | 1978 | 646016 |
| innate resistance of mice to experimental infection with naegleria fowleri. | the mouse system provides an excellent model for studying host resistance to naegleria fowleri, the agent of primary amoebic meningoencephalitis. innate resistance to infection with n. fowleri was examined with respect to infecting dose and the age, sex, and strain of mice. intravenous inoculation with 10(7) amoebae per mouse produced 100% mortality in 9 days, whereas inoculation with fewer amoebae reduced the cumulative mortality. male and female dub/icr mice of varying ages were inoculated int ... | 1978 | 669800 |
| macromolecular composition and nuclear number during growth of naegleria fowleri. | | 1978 | 682075 |
| observations by light microscopy on the cytopathogenicity of naegleria fowleri in mouse embryo-cell cultures. | naegleria fowleri, strain hb-1, caused a destructive cytopathic effect (cpe) in secondary mouse-embryo (me) cells. no evidence was found to suggest that cell-free cytotoxic factors secreted by the amoebae play a part in me-cell destruction. in culture systems designed for the study of cytopathic factors, mammalian-cell damage seemed to occur only as a result of direct contact with active amoebae. this was confirmed when the progressive destruction of individual me cells was observed continuously ... | 1978 | 682176 |
| virulent naegleria fowleri in an indoor swimming pool. | a reservoir of pathogenic naegleria fowleri has been located in the cracked wall of a swimming pool where repeated outbreaks of primary amoebic meningoencephalitis were observed between 1962 and 1965. | 1978 | 684423 |
| comparative antigenic analysis of pathogenic and free-living naegleria species by the gel diffusion and immunoelectrophoresis techniques. | antigens prepared from each of five strains (ca, cj, hb-1, hb-3, and ty) of pathogenic naegleria and the eg strain of nonpathogenic naegleria gruberi were compared by the gel diffusion and immunoelectrophoresis techniques. axenically grown amoebae were used as sources of antigens. antisera were produced in individual rabbits against three strains (ca, cj, and hb-1) of pathogenic naegleria and the eg strain of n. gruberi. in the gel diffusion experiment each of the six antigens was reacted with e ... | 1975 | 803926 |
| experimental infections with pathogenic free-living amebae in laboratory primate hosts: i (a) a study on susceptibility to naegleria fowleri. | studies were conducted on 27 old world monkeys to determine their susceptibility to pathogenic strains (hb-1 and c-66) of naegleria fowleri by intranasal, intravenous, or intrathecal inoculation of trophozoites. no clinically detectable disease resulted from either intranasal or intravenous inoculation, but 11 of 18 monkeys inoculated intrathecally succumed to acutely fatal meningoencephalitis, while the other 7 survived with no obvious permanent brain damage. pathogenicity of n. fowleri appear ... | 1975 | 805226 |
| biologic and serologic characterization of the 161a strain of naegleria fowleri. | the 161a strain of naegleria isolated from the nasal swab of a boy (9) was grown axenically in nelson's medium. when 10,000 amoebae from the axenic medium were inoculated onto each monkey kidney cell (vero) culture, characteristic cytopathic effects (cpe) were noticed in 4 to 5 days. the cpe consisted of granulation of the host cell cytoplasm, cell shrinkage, nuclear pycnosis, and discontinuity of cell sheet. when 10,000 amoebae were instilled intranasally into a group of ten 2- to 3-week-old mi ... | 1975 | 829907 |
| the distribution of naegleria fowleri in man-made thermal waters. | the discharges of 16 thermal polluting factories were examined for the occurrence of naegleria fowleri, the causative agent of primary amebic meningoencephalitis. seven of these waters were shown to harbor this ameba. of 22 n. fowleri isolates, 3 were highly virulent for mice when inoculated intranasally. the three pathogenic strains were isolated from three different places during summer. more n. fowleri were found during summer than in winter, which could be attributed to the lower temperature ... | 1977 | 842770 |
| naegleria fowleri: fine structural localization of acid phosphatase and heme proteins. | | 1977 | 849763 |
| meningoencephalitis due to acanthamoeba sp. pathogenesis and clinico-pathological study. | amebic meningoencephalitis (am) and primary amebic meningoencephalitis (pam) are infectious diseases essentially confined to the central nervous system (cns) and caused by free-living amebas of the genus acanthamoeba (a.) and naegleria (n.) respectively. am due to a. sp. (acanthamoeba castellanii and acanthamoeba culbertsoni) have been reported in chronically ill debilitated individuals, some of them under immunosuppressive therapy, or in immunologically impaired patients without a history of re ... | 1977 | 857580 |
| immunoelectrophoretic study of an environmental, pathogenic naegleria fowleri, isolated in belgium. | | 1977 | 859093 |
| use of an axenic medium for differentiation between pathogenic and nonpathogenic naegleria fowleri isolates. | growth in an axenic medium composed by chang (3rd int. congr. parasitol. munich abstr. icpiii 1:187-188, 1974) allowed separation of pathogenic from nonpathogenic naegleria fowleri strains, since only the former show luxuriant growth in this medium. on the basis of these results, this medium was used in early screening for virulent naegleria isolates. during an extensive ecological study, data were obtained on 102 naegleria strains. twenty of these strains grew luxuriantly in this liquid medium. ... | 1977 | 869525 |
| comparative study of six strains of naegleria with special reference to nonpathogenic variants of naegleria fowleri. | | 1977 | 881654 |
| immunization of mice against naegleria fowleri infection. | naegleria fowleri produces fatal meningoencephalitis in humans and in experimentally infected laboratory animals. the course of the disease in mice is dependent upon the infecting dose of amoebae, route of inoculation, and prior exposure to naegleria antigens. dub/icr mice were immunized by various routes and antigen preparations, held for 21 days, and, together with noninfected control mice, challenged intravenously (i.v.) or intranasally (i.n.) with 10(7) or 10(6) n. fowleri per mouse, respect ... | 1977 | 892900 |
| [study of free living amoebae in the waters of strasbourg. preliminary report (author's transl)]. | 75 strains of free living amoebae were isolated from public drinking water supplies, swimming pools and official swimming ponds in strasbourg. 42 strains were identified till now. no pathogenic strain of naegleria fowleri was found. | 1976 | 984668 |
| in vitro susceptibility of pathogenic naegleria and acanthamoeba speicies to a variety of therapeutic agents. | six pathogenic strains of naegleria fowleri, two of acanthamoeba castellanii, and three of acanthamoeba polyphaga were tested in vitro for susceptibility to a variety of potentially useful therapeutic agents. minimal motility inhibitory concentrations and minimal inhibitory concentrations were determined by a technique of subculturing pure clones of amoebae in plastic tissue culture chamber slides containing liquid axenic media and serially diluted drug, incubating at 30 degrees c for acanthamoe ... | 1976 | 984777 |
| differences in destruction of cysts of pathogenic and nonpathogenic naegleria and acanthamoeba by chlorine. | the destructive action of chlorine on the pathogenic naegleria fowleri and acanthamoeba culbertsoni, the nonpathogenic n. gruberi, and an avirulent acanthamoeba isolate was investigated. n fowleri is somewhat more sensitive to chlorine than n. gruberi, whereas the two acanthamoeba strains are very resistant. this study yields information needed for the destruction of amoebic cysts in drinking water and swimming pools. it also gives some explanation for the occurence of acanthamoeba strains in th ... | 1976 | 999278 |
| microfilaments in naegleria fowleri amoebae. | examination by electron microscopy has revealed 2 types of microfilament in the cytoplasm of 3 strains of axenically grown naegleria fowleri amoebae. thin, actin-like microfilaments 5-7 nm in diameter are randomly oriented in the nonmotile amoebae, and are concentrated near the plasma membrane. in the actively motile amoebae these microfilaments aggregate to form colateral bundles in close proximity to the plasma membrane. thick, myosin-like microfilaments 17-19 nm in diameter also occur in the ... | 1976 | 1033644 |
| the effect of thermal pollution on the distribution of naegleria fowleri. | the distribution in the environment of naegleria fowleri, the causal agent of primary amoebic meningoencephalitis has been investigated in this study. n. fowleri was isolated only from a thermally polluted canal. these amoebaflagellates were not isolated from another thermally polluted canal in the neighbourhood indicating that, apart from high temperature, other factors are involved in the selective proliferation of n. fowleri. this species was absent in all other samples originating from two c ... | 1975 | 1097497 |
| effect of clotrimazole on naegleria fowleri. | the sensitivity of 18 strains of naegleria fowleri to clotrimazole (bay b5097) was tested. they showed minimal inhibitory concentrations in the range 0-03-0-125 mug/ml, and minimal amoebicidal concentrations in the range 0-125-0-25 mug/ml. mice inoculated with n. fowleri were not protected from infection by doses of 100 mg clotrimazole/kg per day given for five days after inoculation. mice had serum levels of up to 6 mug/ml in the first 32 hours after inoculation. therefore clotrimazole appears ... | 1975 | 1141444 |
| in vitro effects of amphotericin b on growth and ultrastructure of the amoeboflagellates naegleria gruberi and naegleria fowleri. | in vitro effects of the polyene antibiotic amphotericin b (amb) on growth, viability, and ultrastructure of amoeboflagellates of the genus naegleria were examined. the strains studied were the nonpathogenic naegleria gruberi eg(b) and the carter and ty strains of the pathogenic naegleria fowleri. amb was amoebicidal at all concentrations used (0.25, 0.50, and 1.0 mug/ml) when the drug was added to cultures in lag phase, as determined by viability testing, but was mainly inhibitory when added to ... | 1975 | 1211914 |
| modification of resistance of mice to naegleria fowleri infections. | naegleria fowleri, which produces a fatal meningoencephalitis in humans, is also able to produce a progressive and fatal disease in mice. the course of the disease in dub/icr mice is dependent upon the infecting dose of organisms, whether administered intraperitoneally (i.p.) or intravenously (i.v.). all of the mice receiving 10(7) trophozoites/mouse i.v. or 4.85 x 10(7) trophozoites/mouse i.p. were killed within 10 days. escherichia coli o26:b6 lipopolysaccharide, administered at a dose of 1 mg ... | 1976 | 1270145 |
| delayed type hypersensitivity in guinea pig infected subcutaneously with naegleria fowleri carter. | a soluble fraction, derived from naegleria fowleri trophozoites disrupted by freeze-thawing, was tested for antigenic properties. intradermal injections of this preparation were administered to guinea pigs previously infected subcutaneously with viable n. fowleri. delayed hypersensitivity to the antigen and loss of weight, the diagnostic symptom of visceral naegleriasis, were observed in the surviving animals. fifty percent of the guinea pigs, however, did not lose weight and had a reduced react ... | 1976 | 1274383 |
| alterations in protein expression and complement resistance of pathogenic naegleria amoebae. | highly pathogenic strains of naegleria fowleri activate the alternative complement pathway but are resistant to lysis. in contrast, weakly pathogenic and nonpathogenic naegleria spp. activate the complement pathway and are readily lysed. the present study was undertaken to determine whether surface components on amoebae accounted for resistance to complement lysis. enzymatic removal of surface components from highly pathogenic n. fowleri with phosphatidylinositol-specific phospholipase c or with ... | 1992 | 1319405 |
| restriction-fragment-length polymorphism and variation in electrophoretic karyotype in naegleria fowleri from japan. | strains of naegleria fowleri isolated in japan from two different places were found to differ in electrophoretic karyotype and restriction-fragment-length polymorphism (rflp) both from each other and from strains isolated on other continents. using the wagner parsimony method on the rflp, we found that the japanese isolates are most closely related to the australian isolates and most distinct from the european isolates. | 1992 | 1359531 |
| appearance in europe of naegleria fowleri displaying the australian type of restriction-fragment-length polymorphism. | we report for the first time the isolation in europe of naegleria fowleri showing a type of restriction-fragment-length polymorphism (rflp) usually found in australia. the presence of this type as well as the european type fluctuated with time in the cooling waters of the nuclear power station investigated. two possible explanations for the appearance of the australian n. fowleri type in europe are presented. | 1992 | 1359532 |
| the production and characterization of anti-naegleria fowleri monoclonal antibodies. | naegleria fowleri, a free-living amoeba commonly found in moist soil and fresh water, enters the body via the nasal mucosa and migrates along the olfactory nerve to the brain, where it causes acute amoebic meningoencephalitis. in the present study 7 clones secreting monoclonal antibodies (mcabs) against n. fowleri were produced and the effector function of them was investigated. their isotypes were igg1 (nf 1, nf 154), igg3 (nf 137) and iga (nf 1, nf 2, nf 256, nf 279). five mcabs (mcab nf 2, nf ... | 1992 | 1374265 |
| identification of acanthamoeba in bronchoalveolar lavage specimens. | acanthamoeba species infect humans occasionally and act as opportunistic pathogens in immunocompromised individuals. this study demonstrates the application of cytocentrifugation as an aid to identification of acanthamoebae. in addition, certain staining procedures clearly optimized visualization of characteristic amoebic features. this was demonstrated by adding amoebae from laboratory cultures to bronchoalveolar lavage specimens. in preparations stained by the papanicolaou, trichrome, or hemat ... | 1992 | 1376659 |
| genotyping naegleria spp. and naegleria fowleri isolates by interrepeat polymerase chain reaction. | all six naegleria species recognized to date were studied by interrepeat polymerase chain reaction (pcr). priming at repeat sequences, which are known to be variable among eukaryotes, yielded electrophoretic dna banding patterns that were specific for any single species. with a single pcr and simple gel electrophoresis, species determination could be performed in less than 1 day. unambiguous discrimination between the pathogen n. fowleri and nonpathogenic naegleria species appeared to be possibl ... | 1992 | 1400959 |
| the arginine-dependent cytolytic mechanism plays a role in destruction of naegleria fowleri amoebae by activated macrophages. | mouse peritoneal macrophages activated by different immunomodulators (mycobacterium bovis bacillus calmette-guérin or propionibacterium acnes) destroy naegleria fowleri amoebae by a contact-dependent process and by soluble cytolytic molecules secreted by macrophages in response to lipopolysaccharide. the goal of this study was to determine whether the arginine-dependent cytolytic mechanism which results in the production of nitric oxide from arginine by activated macrophages destroys the amoebae ... | 1992 | 1452346 |
| separation of soluble amoebicidal and tumoricidal activity of activated macrophages. | macrophage-conditioned medium (m phi cm) prepared from mouse peritoneal macrophages activated in vivo with bacillus calmette-guérin (bcg) or propionibacterium acnes and triggered with lipopolysaccharide in vitro contained tumoricidal and amoebicidal activity. the murine fibroblast cell line l929 was used as the indicator of tumoricidal activity and naegleria fowleri amoeba was used to detect amoebicidal activity in m phi cm. the protease inhibitor, soybean trypsin inhibitor, decreased tumoricida ... | 1992 | 1560419 |
| isolation of naegleria fowleri from pond water in west bengal, india. | | 1992 | 1566303 |
| a method for assessing the migratory response of naegleria fowleri utilizing [3h]uridine-labeled amoebae. | a new procedure is described to assay the migratory response of naegleria fowleri (atcc 30894) amoebae to potential chemoattractants. the method utilizes a blind-well boyden chemotaxis chamber, two micropore filters of different construction, and amoebae-labeled with [3h]uridine. the technique was standardized by determining the influence of incubation time, filter construction, filter pore size and geometry, amoebae to filter pore ratio, and chemoattractant concentration. radiolabeled amoebae w ... | 1992 | 1578403 |
| cloning and characterization of transcripts showing virulence-related gene expression in naegleria fowleri. | the pathogenic lee strain of naegleria fowleri isolated from human or mouse brain loses pathogenicity when cultured axenically in a nutrient broth. to identify genes differentially expressed in highly virulent versus weakly virulent amoebae, a cdna library was constructed by using mrna from amoebae recovered from a mouse brain. two cdna clones were isolated by differential screening of the library. the transcript homologous to clone nf314 was preferentially expressed in highly virulent cells, wh ... | 1992 | 1587609 |
| primary amebic meningoencephalitis--north carolina, 1991. | during september 1991, two children in north carolina died from primary amebic meningoencephalitis (pam), a rare and often fatal illness resulting from infection with naegleria fowleri. this report summarizes clinical and epidemiologic information about these two cases and characterizes n. fowleri infection. | 1992 | 1608390 |
| [the protective effects of monoclonal antibodies in mice from naegleria fowleri infection]. | protective effects of monoclonal antibodies against n. fowleri were comparatively studied. balb/c mice were treated with two types of monoclonal antibodies, nf 2 and nf 154, before and after the infection with n. fowleri. the mortality and mean survival times were then compared. also, direct effect of the monoclonal antibodies on the n. fowleri trophozoites in vitro were observed. in vitro protective effects of the monoclonal antibodies were also studied in cells infected with n. fowleri. the ob ... | 1992 | 1627499 |
| from the centers for disease control. primary amebic meningoencephalitis--north carolina, 1991. | | 1992 | 1640602 |
| [natural killer cell activity in naegleria fowleri infected mice]. | the natural killer (nk) cell activity of splenocytes and recycling capacity of nk cells were observed by combining the 51cr-release cytotoxicity assay and single cell cytotoxicity assay against yac-1. the icr mice were infected intranasally with naegleria fowleri, that is a pathogenic free-living amoeba. the mice infected with 1 x 10(5) trophozoites showed mortality rate of 76.7% and mean survival time of 12.9 days. the cytotoxic activity of nk cells in infected mice was significantly higher tha ... | 1991 | 1786253 |
| flagella number among naegleria flagellates. | scanning electron microscopy was used to determine the number of flagella on the flagellates of naegleria australiensis, n. fowleri, n. gruberi, and n. jadini. although the majority of flagellates had 2 flagella, there was considerable variation among individual cells. the number of flagella per flagellate varied from 1-8, with 2.4 being the average number per cell. for the different species, the average number of flagella per cell ranged from 2.0 in n. jadini to 3.1 for n. australiensis. the gr ... | 1991 | 1822460 |
| virulence-related protein synthesis in naegleria fowleri. | protein synthesis patterns of the low-virulence naegleria fowleri lee strain from axenic culture, the same strain after mouse brain passage to increase virulence, and the same strain after growth on bacteria were studied. comparisons of accumulated proteins, in vivo-synthesized proteins, and in vitro-synthesized proteins translated from poly(a)+ mrna were made. differences between amoebae from the different treatments were noted. after 6 months in axenic culture, pathogenic protein synthesis pat ... | 1991 | 1937787 |
| thermal ecology of naegleria fowleri from a power plant cooling reservoir. | the pathogenic, free-living amoeba naegleria fowleri is the causative agent of human primary amebic meningoencephalitis. n. fowleri has been isolated from thermally elevated aquatic environments worldwide, but temperature factors associated with occurrence of the amoeba remain undefined. in this study, a newly created cooling reservoir (clinton lake, illinois) was surveyed for naegleria spp. before and after thermal additions from a nuclear power plant. water and sediment samples were collected ... | 1990 | 1975164 |
| amplification of repetitive dna for the specific detection of naegleria fowleri. | by using hybridization at low c0t values, a genomic library on naegleria fowleri was screened for clones containing repetitive dna. partial sequence information from a repetitive clone, nf9, showed sequence homologies with the mitochondrial atpase 6 subunit from yeasts and other organisms. synthetic dna primers were selected and tested in amplification reactions. nonstringent hybridization conditions were defined which allowed amplification of n. fowleri dna and reduced amplification of dna from ... | 1991 | 2007628 |
| free-living amoebae: pathogenicity and immunity. | free-living amoebae causes three well-defined disease entities: (i) primary amoebic meningoencephalitis, caused by naegleria fowleri, (ii) granulomatous amoebic encephalitis and (iii) chronic amoebic keratitis, caused by species of acanthamoeba. both naegleria infections and chronic amoebic keratitis occur in healthy individuals while granulomatous amoebic encephalitis is often associated with patients with acquired immunodeficiencies. the different pathogenic behaviour of these organisms is ass ... | 1991 | 2014136 |
| fresh-water amoebae from four aquatic sites in egypt. | water samples from four aquatic sites in egypt were examined for the presence of free-living amoebae. amoebae were isolated and cultured on 1.5% non-nutrient agar with bacteria. they were studied morphologically and tested for production of flagellated forms, encystment, excystment, nuclear division, temperature tolerance and pathogenicity in young mice (8 - 10 gm). didascalus thorntoni and naegleria gruberi were dominant in all surface waters. naegleria fowleri, acanthamoeba glebae, a. culberts ... | 1991 | 2033288 |
| free-living amoebae in egypt. 1. naegleria gruberi and naegleria fowleri. | two naegleria species were isolated and identified from various water sources in lower and upper egypt. identification was based on the morphology, nuclear division and the excystation and flagellation tests. the trophic, cystic and flagellate forms of n. gruberi are larger than those of n. fowleri and the cyst of the former species has one or more pores while that of the latter species has no pores and has an outer gelatinous layer. the size and the morphological characteristics of these two fr ... | 1991 | 2033306 |
| phagocytosis of human erythrocytes by naegleria is not related to species pathogenicity. a phase-contrast cinemicrographic study. | this phase contrast cinemicrographic study evaluated the phagocytic activity of naegleria spp. (naegleria fowleri, naegleria australiensis and naegleria lovaniensis) towards human red cells. thus erythrophagocytosis, a marker of pathogeneicity for entamoeba histolytica, did not correlate with virulence in either the pathogenic or non-pathogenic naegleria spp. tested. our study also revealed no quantitative differences in phagocytosis by naegleria spp. of human erythrocytes. | 1991 | 2067415 |
| extracts of artemisia abrotanum and artemisia absinthium inhibit growth of naegleria fowleri in vitro. | | 1991 | 2068769 |
| cytopathic action of naegleria fowleri amoebae on rat neuroblastoma target cells. | the axenically cultured, weakly pathogenic naegleria fowleri lee and the highly pathogenic, mouse passaged n. fowleri leemp are cytopathic for b103 rat nerve cells in culture. cytopathogenicity was measured by release of radiolabeled rubidium or radiolabeled chromium from b103 target cells. cytopathogenicity was time-dependent for up to 18 h and dependent upon amoebae effector to nerve cell target ratios of less than 1:1. release of 51cr from b103 cells by either lee or leemp amoebae was enhance ... | 1990 | 2108243 |
| pathogenic free-living amoebae. | studies on pathogenic free-living amoebae performed in korea were briefly reviewed. one strain of naegleria fowleri was isolated from the sewage, and 3 strains of acanthamoeba culbertsoni from a reservoir and the gill of fish. they were identified by morphological characteristics. three strains among the 4 were experimentally proved pathogenic to cause primary amoebic meningoencephalitis in mice. the virulence of n. fowleri depended upon various factors such as strain, weight and sex of mice, an ... | 1990 | 2133420 |
| characterization of potentially pathogenic free-living amoebae in sewage samples of calcutta, india. | 1. it is widely accepted that foul or polluted environments are the principal sources of potentially pathogenic species of free-living amoebae. the present paper is the first report of occurrence of potentially pathogenic free-living amoebae in sewage samples of calcutta, india. 2. we describe the occurrence, isolation, specific identification and comparative mouse pathogenicity test of two pathogenic amoebae, viz., naegleria fowleri (n. aerobia) carter, 1970, causing human meningoencephalitis a ... | 1990 | 2136561 |
| naegleria and acanthamoeba infections: review. | infections caused by small, free-living amebas are still unfamiliar to many clinicians, pathologists, and laboratorians. as of 31 july 1989, more than 140 cases of primary amebic meningoencephalitis caused by naegleria fowleri and more than 40 cases of granulomatous amebic encephalitis caused by acanthamoeba species (including two cases in patients with aids) and possibly by other free-living amebas had occurred worldwide. the recent increase in acanthamoeba keratitis (more than 200 cases), espe ... | 1990 | 2193354 |
| inactivation of legionella pneumophila by monochloramine. | chloramination which is used in south australia to control the growth of naegleria fowleri, was investigated to see if it would also control that of legionella pneumophila. it was found that l. pneumophila was more sensitive than escherichia coli to monochloramine. at 1.0 mg/l, a 99% kill of l. pneumophila was achieved in 15 min compared with 37 min for a 99% kill of e. coli. combined with the stability of monochloramine, even at elevated temperatures, the results suggest that this disinfectant ... | 1990 | 2196255 |
| differentiation of naegleria fowleri from acanthamoeba species by using monoclonal antibodies and flow cytometry. | monoclonal antibodies to naegleria fowleri and acanthamoeba polyphaga were analyzed by enzyme-linked immunosorbent assay, indirect immunofluorescence microscopy, and fluorescence flow cytometry to assess specificity and cross-reactivity with axenically cultured n. fowleri and acanthamoeba spp. four monoclonal antibodies to n. fowleri were specific for n. fowleri and had no reactivity to a. polyphaga. similarly, four monoclonal antibodies to a. polyphaga did not react with n. fowleri. two of the ... | 1990 | 2229384 |
| susceptibility of wild mammals to infection with naegleria fowleri. | animals of 4 families of small wild mammals were live-trapped and inoculated intranasally with naegleria fowleri to determine patterns of susceptibility. of the 7 species of animals examined, only rodents were susceptible to n. fowleri. susceptible animals were eastern gray squirrel, hispid cotton rat, muskrat, and house mouse. mammals that were not susceptible at a dose of 10(6) were opossum, raccoon, and eastern cottontail rabbit. perhaps rodents and humans share a common anatomical or physiol ... | 1990 | 2254821 |
| epidemiology of free-living ameba infections. | small free-living amebas belonging to the genera acanthamoeba and naegleria occur world-wide. they have been isolated from a variety of habitats including fresh water, thermal discharges of power plants, soil, sewage and also from the nose and throats of patients with respiratory illness as well as healthy persons. although the true incidence of human infections with these amebas is not known, it is believed that as many as 200 cases of central nervous system infections due to these amebas have ... | 1990 | 2258827 |
| ultrastructural studies on the effect of tumor necrosis factor on the interaction of neutrophils and naegleria fowleri. | naegleria fowleri is the common etiologic agent of primary amebic meningoencephalitis (pam). we investigated the interaction of human neutrophils with naegleria trophozoites and examined the effect of neutrophil stimulation by the recombinant human tumor necrosis factor (tnf) on this interaction. as indicated by scanning and transmission electron microscopy, tnf stimulated the adherence of neutrophils to n. fowleri with destruction of the ameba. neutrophil iodination, an indirect measure of stim ... | 1990 | 2316792 |
| the interaction of naegleria fowleri amoebae with murine macrophage cell lines. | the present study was undertaken to determine whether murine macrophage cell lines exhibited in vitro amoebicidal activity comparable to that elicited by activated murine peritoneal macrophages. peritoneal macrophages activated in vivo by bacillus calmette-guérin or propionibacterium acnes demonstrated significant cytolysis of naegleria fowleri amoebae. the macrophage cell line raw264.7 also effected cytolysis of amoebae, but to a lesser extent than that elicited by activated peritoneal macropha ... | 1990 | 2359044 |
| soluble amoebicidal factors mediate cytolysis of naegleria fowleri by activated macrophages. | murine peritoneal macrophages activated in vivo with corynebacterium parvum or bacille calmette-guérin, in contrast to resident macrophages, demonstrated significant cytolysis of the amoeba, naegleria fowleri. catalase and superoxide dismutase, both alone and in combination, failed to inhibit cytolysis of amoebae. n. fowleri amoebae demonstrated significant resistance to exogenously added hydrogen peroxide. the hydroxyl radical scavengers mannitol, thiourea, and dimethyl sulfoxide, as well as an ... | 1986 | 2427211 |
| biochemical and functional characterization of a membrane-associated pore-forming protein from the pathogenic ameboflagellate naegleria fowleri. | a membrane-bound cytolytic pore-forming protein (n-pfp) produced by the pathogenic ameboflagellate naegleria fowleri was characterized. n-pfp was solubilized from ameba membranes by detergent and enriched 300-fold by gel filtration chromatography. when analyzed by gel electrophoresis, n-pfp migrates with a molecular mass of 66 kda and 50-54 kda, under reducing and non-reducing conditions, respectively. in addition to lysing erythrocytes, n-pfp is cytotoxic to several tumor cell lines tested. its ... | 1989 | 2463245 |
| [resistance to naegleria fowleri infection passively acquired from immunized splenocyte, serum or milk]. | a pathogenic free-living amoeba, naegleria fowleri, causes primary amoebic meningoencephalitis to human and experimental animals. this infection is rare, but the mortality is very high. nowadays, drug treatment or active immunization of human or mice are being tried with partial effectiveness. this study shows passive immunization effect by transfer of immunized spleen cells, serum, or milk from immunized mother in mouse experimental model. young balb/c mice were immunized intraperitoneally with ... | 1989 | 2486833 |
| [studies on the cell-mediated immunity in experimental naegleria spp. infections]. | observations were made on the differences in cell-mediated immune responses in the mice infected with strongly pathogenic naegleria fowleri itmap 359, weakly pathogenic naegleria jadini 0400, or non-pathogenic naegleria gruberi egb, respectively. variations in cell-mediated responses and changes in antibody titers according to the duration after infection were noted. infections were done by dropping 5 microliters saline suspension containing 10 x 10(4) trophozoites cultured axenically in the cgv ... | 1989 | 2486928 |
| membrane carbohydrate characterization of acanthamoeba astronyxis, a. castellanii and naegleria fowleri by fluorescein-conjugated lectins. | a comparative study of membrane carbohydrate characteristics of pathogenic and non-pathogenic trophozoites and cysts of free-living acanthamoeba castellanii, naegleria fowleri and a. astronyxis, respectively from sewage sludge in india was carried out by means of fluorescein-conjugated lectin binding using eight lectins. two lectins, viz. concanavalin a and phytohaemagglutinin p, could bind all free-living amoebae at different concentrations. the most notable feature of the study is that peanut ... | 1989 | 2592141 |
| [primary amebic meningoencephalitis caused by naegleria fowleri in an adolescent from huetamo, michoacan, mexico]. | a 13 year old boy died after a three day illness with severe headache, explosive vomiting, fever and progressive loss of consciousness. the autopsy revealed purulent and necrotizing meningoencephalitis mainly involving the basal regions and posterior fossa and on microscopic examination numerous trophozoites of naegleria were seen in the meninges and necrotic brain tissue. the trophozoites were identified as naegleria fowleri by immunoperoxidase staining. this case as well as others previously r ... | 1989 | 2604877 |
| cytopathogenicity of naegleria fowleri in mammalian cell cultures. | a total of 13 strains of naegleria fowleri were cytopathogenic for lung, kidney, foreskin, ovary, connective tissue, neuroblastoma, laryngeal carcinoma, and cervical carcinoma mammalian cell lines. the strains of n. fowleri varied considerably in their ability to produce a cytopathic effect (cpe). likewise, the different mammalian cell lines exhibited varying degrees of susceptability to the cytopathogenicity of the amebae. the african green-monkey kidney (vero) cell line proved to be useful for ... | 1989 | 2622894 |
| a temporary flagellate (mastigote) stage in the vahlkampfiid amoeba willaertia magna and its possible evolutionary significance. | a temporary flagellate (mastigote) stage has been observed in several isolates of the vahlkampfiid amoeba willaertia magna. in an australian isolate studied in detail, flagellates appeared synchronously, although later than in naegleria fowleri or n. lovaniensis under similar conditions (half-maximal time, t50 = 168 min at 37 degrees c). the flagellates initially have four flagella and lack a cytostome, but undergo several successive divisions, the first of them synchronous, resulting in progres ... | 1989 | 2624890 |
| altered neutrophils in mice immune to experimental naegleria amoebic meningoencephalitis. | naegleria fowleri is the cause of primary amoebic meningoencephalitis in man. the mouse is considered to be a suitable experimental model for this disease. the data presented shows that blood neutrophils from n. fowleri immune mice (immunised) that had received a 'recall' amoeba antigen had altered responses compared with those from similarly treated normal mice. the neutrophils from immune animals showed increased basal levels of oxygen-dependent respiratory activity, measured by the chemilumin ... | 1989 | 2628288 |
| primary amoebic meningoencephalitis in thailand: report of a case and review literatures. | primary amoebic meningoencephalitis (pam) which is caused by free-living amoeba, naegleria fowleri, is a rare disease. we report the fifth case in thailand in order to add more information. the patient was a previously healthy 4 1/2-year-old girl from nakhon pathom province. for several weeks before this illness she had swum in a water supply canal. she developed high fever with change in consciousness. her cerebrospinal fluid contained numerous naegleria fowleri which grew in culture media and ... | 1989 | 2659717 |
| naegleria fowleri: phase contrast cinemicrographic study of phagocytosis of human erythrocytes. | | 1989 | 2676578 |
| acanthamoeba culbertsoni and naegleria fowleri: occurrence of antibodies in man. | serum samples of 1,054 inhabitants of bohemia (czechoslovakia) were examined by means of indirect haemagglutination test with antigens from naegleria fowleri and acanthamoeba culbertsoni. with n. fowleri antigen the frequency of positive reactions did not exceed 3.5 per cent in lowest serum dilutions only. n. fowleri could not be identified as a possible causative agent in any chronic form of disease in man. significant accumulation of positive findings with a. culbertsoni antigen was observed i ... | 1989 | 2723426 |
| evaluation of evolutionary divergence in the genus naegleria by analysis of ribosomal dna plasmid restriction patterns. | ribosomal dna (rdna) plasmid restriction maps of 10 strains and rdna hybridisation patterns of 61 additional strains have been used to assess inter- and intra-specific diversity and phylogenetic relationships in the genus naegleria. the results obtained by this method largely confirm those of previous studies based on a variety of other criteria. they indicate that very little variation exists within the pathogenic species naegleria fowleri despite its worldwide distribution and that it is close ... | 1989 | 2733731 |
| augmentation of the neutrophil response to naegleria fowleri by tumor necrosis factor alpha. | conditioned medium from phytohemagglutinin-stimulated human mononuclear leukocytes, previously shown to activate neutrophils for amoeba killing, was found to contain high levels of tumor necrosis factor alpha (tnf-alpha) by an enzyme-linked immunosorbent assay. the effects of human recombinant tnf-alpha on the response of human neutrophils to the pathogenic free-living amoeba naegleria fowleri was studied in vitro. the data showed that recombinant human tnf-alpha augmented the neutrophil respira ... | 1989 | 2777375 |
| resistance of highly pathogenic naegleria fowleri amoebae to complement-mediated lysis. | weakly pathogenic and nonpathogenic naegleria spp. are readily lysed by human and guinea pig complement. highly pathogenic naegleria fowleri are resistant to complement-mediated lysis. electrophoretic analysis of normal human serum (nhs) incubated with pathogenic or nonpathogenic naegleria spp. demonstrates that amoebae activate the complement cascade, resulting in the production of c3 and c5 complement cleavage products. to determine whether surface constituents play a role in resistance to com ... | 1989 | 2807551 |
| nasal carriage of naegleria fowleri and its environmental occurrence in borno state, nigeria. | the presence of free living amoebae was investigated in the nasal passages of 50 healthy children and in environmental sources in maiduguri, borno state of nigeria. three of the children yielded positive cultures of naegleria fowleri. all the five water samples and two of the nine soil samples examined from different localities were positive for n. fowleri. the isolates proved pathogenic for laboratory mice causing a fatal meningoencephalitis. the epidemiological significance of the findings is ... | 1989 | 2809145 |
| geographic origin and spread of pathogenic naegleria fowleri deduced from restriction enzyme patterns of repeated dna. | the restriction enzyme patterns of repeated dna from 20 naegleria fowleri and 13 n. gruberi strains were compared. on this basis strains of n. fowleri could be easily separated from n. gruberi. although the restriction enzyme profiles of n. fowleri strains are quite homogenous, strains originating from europe and from australia had slightly different patterns. both european and australian profiles were found in the usa. in australia a genetic variant was detected that is the same as the n. fowle ... | 1988 | 2840136 |
| acanthamoeba, an opportunistic microorganism: a review. | granulomatous amebic encephalitis due to acanthamoeba spp. usually occurs in chronically ill and debilitated individuals. some of these patients may have received immunosuppressive therapy. another infection due to acanthamoeba spp. has been corneal ulcerations which usually occur after minimal trauma to the corneal epithelium (1). in contrast, primary amebic meningoencephalitis due to naegleria fowleri usually occurs in healthy, young individuals with a history of swimming in heated swimming po ... | 1985 | 2867047 |