| immunisation against gastric helicobacter infection in a mouse/helicobacter felis model. | | 1992 | 1349142 |
| inhibition of acid secretion from parietal cells by non-human-infecting helicobacter species: a factor in colonization of gastric mucosa? | helicobacter pylori has been shown to produce a protein that inhibits acid secretion from parietal cells. we have examined other non-human-infecting helicobacter species for this property by measuring the uptake of [14c]aminopyrine into rabbit parietal cells as an indirect assessment of acid secretion. helicobacter felis and an isolate from a rhesus monkey were shown to inhibit acid secretion. isolates of helicobacter mustelae gave variable responses. whole bacteria and cell-free sonicates impai ... | 1991 | 1894369 |
| partial characterization and effect of omeprazole on atpase activity in helicobacter pylori by using permeabilized cells. | atpase activity in permeabilized cells of helicobacter pylori as well as those of helicobacter felis and campylobacter jejuni was analyzed. the atpase activities in these cells were most susceptible to sodium azide, fluoroaluminate, and dicyclohexylcarbodiimide, which are typical inhibitors of f atpases. optimal values for maximal activity were found to be at approximately ph 6.4, 6.0, and 6.0 for c. jejuni, h. pylori, and h. felis, respectively. the substituted benzimidazole compounds omeprazol ... | 1995 | 7486907 |
| genetic organization of a small cryptic plasmid of helicobacter pylori. | a 2.9-kb cryptic plasmid of helicobacter pylori (hp), phel1, was isolated and the complete nucleotide (nt) sequence was determined. an open reading frame (orf1) was identified encoding a putative polypeptide of 63,709 da, the existence and correct size of which was confirmed by t7 promoter expression analysis. the orf1 sequence showed strong amino-acid sequence identity to a recently identified putative orf1 protein of a cryptic hp plasmid, phpm180, and significant homologies to putative rep pro ... | 1995 | 7489910 |
| oral immunization induces humoral and cell-mediated immunity and protects germ-free mice against infection from helicobacter felis. | | 1995 | 7502874 |
| expression of adhesion molecules on human granulocytes after stimulation with helicobacter pylori membrane proteins: comparison with membrane proteins from other bacteria. | type b gastritis in its active form is characterized by a dense infiltration of the lamina propria with granulocytes. since the bacterium helicobacter pylori does not invade the epithelial barrier, a signaling pathway chemoattractive for granulocytes must exist across this mucosal boarder. one possible mechanism tested was whether granulocytes are directly activated by water-soluble membrane proteins (wsp) from h. pylori. these findings were compared with the effects of wsp from other bacteria ( ... | 1995 | 7540595 |
| identification of helicobacter pylori by immunological dot blot method based on reaction of a species-specific monoclonal antibody with a surface-exposed protein. | monoclonal antibodies (mabs) against membrane preparations of helicobacter pylori were produced. one mab was found to be specific for h. pylori, because it did not react with a number of other bacterial species, including helicobacter felis and campylobacter jejuni. this mab reacted with a 30-kda protein found in outer membrane preparations of h. pylori. the protein was also detected on the cell surface on intact bacteria when analyzed by immunoelectron microscopy. to facilitate the identificati ... | 1995 | 7714196 |
| oral immunization with recombinant helicobacter pylori urease induces secretory iga antibodies and protects mice from challenge with helicobacter felis. | helicobacter pylori, a gram-negative spiral bacterium, is the cause of chronic superficial (type b) gastritis and peptic ulcer disease. the urease enzyme of h. pylori was expressed as an inactive recombinant protein in escherichia coli, purified as particulate structures of 550-600 kda molecular mass with a diameter of approximately 12 nm. given orally, 5 micrograms of urease with an appropriate mucosal adjuvant, such as the labile toxin of e. coli, protected 60%-100% of mice against challenge w ... | 1995 | 7797906 |
| animal and public health implications of gastric colonization of cats by helicobacter-like organisms. | the bacterial genus helicobacter contains a number of species which colonize the gastric mucosa of mammals. natural and/or experimental gastric pathology has been correlated with colonization in humans and a wide variety of animal species. historical reports in the literature suggest that a high percentage of cats are colonized by large, spiral, gastric helicobacter-like organisms (ghlos). one of these bacteria (helicobacter felis) has been isolated on artificial media and has experimentally cau ... | 1994 | 8027308 |
| protection of germ-free mice from infection by helicobacter felis after active oral or passive iga immunization. | helicobacter pylori infection of human gastric epithelium has been associated with gastritis, ulcers and gastric cancers. in an h. felis, germ-free mouse model of infection, oral immunization with bacterial antigens plus cholera toxin resulted in elevated serum, gastric and intestinal anti-h. felis antibody titres and protection from acute infection. mice given monoclonal iga anti-h. felis antibody at the time of initial challenge were also protected from infection. these results demonstrate tha ... | 1993 | 8322486 |
| helicobacter acinonyx sp. nov., isolated from cheetahs with gastritis. | four strains of a novel helicobacter species were isolated from the stomachs of cheetahs (acinonyx jubilatus) with gastritis. these isolates were phenotypically similar to helicobacter pylori. the isolates were gram-negative, spiral bacteria which grew under microaerophilic conditions at 37 degrees c, but not at 25 or 42 degrees c, and produced urease, catalase, oxidase, alkaline phosphatase, and gamma-glutamyl transpeptidase. the isolates did not ferment glucose, mannitol, inositol, sorbitol, r ... | 1993 | 8379970 |
| cloning, expression and sequencing of helicobacter felis urease genes. | urease genes from helicobacter felis were cloned and expressed in escherichia coli cells. a genomic bank of sau3a-digested h. felis chromosomal dna was created using a cosmid vector. cosmid clones were screened for urease activity following subculture on a nitrogen-limiting medium. subcloning of dna from an urease-positive cosmid clone led to the construction of pill205 (9.5 kb) which conferred a urease activity of 1.2 +/- 0.5 mumole urea min-1 mg-1 bacterial protein to e. coli hb101 bacteria gr ... | 1993 | 8412683 |
| gastric colonization of the ferret with helicobacter species: natural and experimental infections. | helicobacter mustelae, isolated from the stomachs of adult ferrets, appears to have a world-wide distribution. ferrets are colonized with h. mustelae at a young age, usually 5-6 weeks; in our experience 100% of adult ferrets are colonized in both the antrum and the fundus. gastric infection correlates with elevation of serum igg antibodies to h. mustelae. in the oxyntic mucosa the presence of superficial gastritis coincides closely with the presence of h. mustelae. in the distal antrum the organ ... | 1991 | 1833810 |
| transmission of helicobacter spp. a challenge to the dogma of faecal-oral spread. | faecal oral spread is claimed by many to be the mode of transmission of the gastric pathogen helicobacter pylori. this idea is based not on experimental data but because the epidemiology of h. pylori infection resembles that of other pathogens known to be spread by the faecal-oral route. this is in spite of the observation that no-one has been successful in culturing h. pylori from human stool. in this study, a series of transmission experiments are reported on animals infected with the gastric ... | 1991 | 1831765 |
| phylogeny of helicobacter felis sp. nov., helicobacter mustelae, and related bacteria. | strain cs1t (t = type strain) is a gram-negative, microaerophilic, urease-positive, spiral-shaped bacterium that was isolated from the gastric mucosa of a cat. additional strains which possessed biochemical and ultrastructural characteristics similar to those of strain cs1t were isolated from the gastric mucosa of cats and dogs. the guanine-plus-cytosine content of the dna of strain cs1t was 42.5 mol%. the 16s rrna sequences of strain cs1t, strain ds3 (a spiral-shaped isolate from a dog), and he ... | 1991 | 1704791 |
| hypertrophic gastropathy in helicobacter felis-infected wild-type c57bl/6 mice and p53 hemizygous transgenic mice. | helicobacter pylori infection causes gastritis and peptic ulcers and is linked epidemiologically to gastric cancer. to analyze host genetic factors and the influence of helicobacter on cell proliferation, we used an inbred and p53 hemizygous mouse model of helicobacter felis-induced gastritis. | 1996 | 8536852 |
| role of helicobacter felis in chronic canine gastritis. | five gnotobiotic beagle dogs were orally inoculated with a pure culture of helicobacter felis. the remaining two littermates served as contact controls. thirty days after infection, all animals were euthanatized and specimens were collected for evaluation. in infected dogs, h. felis was recovered from all areas of the stomach. colonization was heaviest in the fundus and antrum. h. felis was not cultured from any segment of the gastrointestinal tract distal to the duodenum. two weeks after infect ... | 1992 | 1448894 |
| identification and molecular characterization of a major ring-forming surface protein from the gastric pathogen helicobacter mustelae. | the spiral microaerophilic bacterium helicobacter mustelae is linked to gastritis and gastric ulcers in ferrets. electron microscopy of h. mustelae showed the presence of a laterally extensive array of 8.5-nm-diameter rings on the cell surface, which was shown to be composed of a 150kda protein. this protein was purified, and the sequence of 10 amino-terminal residues was determined. polyclonal antibody against the purified 150 kda protein labelled the ring structures on the homologous strain by ... | 1994 | 8170397 |
| immunological and molecular characterization of helicobacter felis urease. | urease activity has recently been shown to be an important virulence determinant for helicobacter pylori, allowing it to survive the low ph of the stomach during colonization. experimental murine infection with helicobacter felis is now being used as a model for h. pylori infection to study the effects of vaccines, antibiotics, and urease inhibitors on colonization. however, little information comparing the ureases of h. felis and h. pylori is available. urease was partially purified from the ce ... | 1994 | 8112850 |
| successful immunization against gastric infection with helicobacter species: use of a cholera toxin b-subunit-whole-cell vaccine. | in previous studies we found that immunizing mice with a sonicate of helicobacter felis and adjuvant cholera toxin (ct; 10 micrograms) protected the animals against challenge with viable h. felis. the aim of this study was to determine whether a low dose of ct or its nontoxic b subunit (ctb) was effective as an adjuvant in helicobacter oral vaccines. significant protection against viable h. felis challenge was achieved in the animals immunized with h. felis antigen plus the combination of 0.5 mi ... | 1994 | 8039937 |
| recombinant antigens prepared from the urease subunits of helicobacter spp.: evidence of protection in a mouse model of gastric infection. | urease is an important virulence factor for gastric helicobacter spp. to elucidate the efficacy of individual urease subunits to act as mucosal immunogens, the genes encoding the respective urease subunits (urea and ureb) of helicobacter pylori and helicobacter felis were cloned in an expression vector (pmal) and expressed in escherichia coli cells as translational fusion proteins. the recombinant urea and ureb proteins were purified by affinity and anion-exchange chromatography techniques and h ... | 1994 | 7927778 |
| immunization of balb/c mice against helicobacter felis infection with helicobacter pylori urease. | because helicobacter pylori is a potentially dangerous human pathogen, the protective potential of oral immunization with h. pylori urease and its subunits was evaluated in an animal model. | 1994 | 7926454 |
| urease-specific monoclonal antibodies prevent helicobacter felis infection in mice. | experiments were performed to determine the antigenic specificity of a monoclonal antibody (immunoglobulin a [iga] 71) previously demonstrated to neutralize the ability of helicobacter felis to colonize mice. immunoprecipitation of radiolabeled h. felis outer membrane proteins with iga 71 revealed specificity for a 62-kda protein. another of our monoclonal antibodies, igg 40, precipitated a protein of similar molecular weight. iga 71 but not igg 40 also precipitated purified recombinant h. pylor ... | 1995 | 7890401 |
| effect of oral immunization with recombinant urease on murine helicobacter felis gastritis. | the ability of oral immunization to interfere with the establishment of infection with helicobacter felis was examined. groups of swiss webster mice were immunized orally with 250 micrograms of helicobacter pylori recombinant urease (rurease) and 10 micrograms of cholera toxin (ct) adjuvant, 1 mg of h. felis sonicate antigens and ct, or phosphate-buffered saline (pbs) and ct. oral immunization with rurease resulted in markedly elevated serum immunoglobulin g (igg), serum iga, and intestinal iga ... | 1995 | 7890380 |
| helicobacter-associated gastritis in scid mice. | immunodeficient (scid) and immunocompetent mice were infected with helicobacter felis to address the role of autoimmunity in helicobacter-associated gastritis. the extents of inflammation were equivalent in the two groups. the numbers of h. felis organisms were marginally increased in the scid mice but did not achieve statistical significance. these results indicate that autoimmunity is not necessary to induce disease and that the presence of an adaptive immune system does not significantly affe ... | 1995 | 7868235 |
| oral immunization with helicobacter pylori urease b subunit as a treatment against helicobacter infection in mice. | eradication of helicobacter pylori infections in humans results in the healing of gastritis and gastric ulcers. this study used a mouse model to test whether oral vaccination can cure helicobacter infection and gastritis. | 1995 | 7797009 |
| the importance of local acid production in the distribution of helicobacter felis in the mouse stomach. | helicobacter felis colonizes the gastric mucosa of rodents. preliminary studies showed differences in the distribution of the organism in different parts of the stomach that seemed related to the secretory capacity of the mucosa. the aim of this study was to determine the localization of h. felis in the mouse stomach and to investigate the influence of acid-suppressive agents. | 1995 | 7729630 |
| helicobacter infection and gastric ethanol metabolism. | the organism frequently colonizing the stomach of patients suffering from chronic active gastritis and peptic ulcer disease--helicobacter pylori--possesses marked alcohol dehydrogenase (adh) activity. consequently, helicobacter infection may contribute to the capacity of the stomach to metabolize ethanol and lead to increased acetaldehyde production. to study this hypothesis, we first determined adh activity in a variety of h. pylori strains originally isolated from human gastric mucosal biopsie ... | 1994 | 7695020 |
| maltoma-like lesions in the murine gastric mucosa after long-term infection with helicobacter felis. a mouse model of helicobacter pylori-induced gastric lymphoma. | the long-term consequences of helicobacter infection were observed in an established murine model of human helicobacter infection. stomachs of specific pathogen-free balb/c mice infected with helicobacter felis were examined for inflammation with particular reference to lymphoid cell proliferation and lymphoepithelial lesions. there was little evidence of an inflammatory response in animals sacrificed up to 19 months after infection. in contrast, from 22 months, 38% of infected animals had lymph ... | 1995 | 7604881 |
| the groes homolog of helicobacter pylori confers protective immunity against mucosal infection in mice. | helicobacter pylori is an important etiologic agent of gastroduodenal disease. in common with other organisms, h. pylori bacteria express heat shock proteins that share homologies with the groes-groel class of proteins from escherichia coli. we have assessed the heat shock proteins of h. pylori as potential protective antigens in a murine model of gastric helicobacter infection. orogastric immunization of mice with recombinant h. pylori groes- and groel-like proteins protected 80% (n = 20) and 7 ... | 1995 | 7604021 |
| a small animal model of human helicobacter pylori active chronic gastritis. | isolation of a spiral-shaped bacterium closely related to helicobacter pylori from the cat stomach made it possible to investigate new small animal models of gastric infection. pure cultures of this bacterium, provisionally named "helicobacter felis," were fed to germ-free mice. the organism colonized the stomach in large numbers in mucus and deep in the gastric pits and showed the same gastric trophism found with h. pylori. significant histopathology was seen in all h. felis-infected mice. at 2 ... | 1990 | 2210240 |
| protective immunization against helicobacter stimulates long-term immunity. | immunization with an oral vaccine composed of whole cell sonicates of helicobacter felis plus cholera toxin (ct) can protect mice from h. felis challenge. the aim of this study was to determine whether this protective immunity was long-lived. mice were given the vaccine then left for up to 15 months before challenge. after 15 months, all mice were still protected from h. felis infection, indicating that oral immunization using bacterial antigens plus ct can stimulate long-term local immunologica ... | 1996 | 8817825 |
| helicobacter felis gastritis in gnotobiotic rats: an animal model of helicobacter pylori gastritis. | the gastric spirillum helicobacter felis, originally isolated from the cat stomach, colonizes the stomachs of germfree rats. studies were designed to examine the pathological and serological responses of germfree rats inoculated orally with h. felis. at 2 weeks postinoculation, the gastric mucosa of germfree rats had lymphocytes and eosinophils scattered in small foci throughout the subglandular region of the antrum. small numbers of lymphocytes were present in the subglandular portion of the an ... | 1991 | 1997430 |
| gastric bacteria other than helicobacter pylori. | since the culture of helicobacter pylori from the human stomach in 1983 there has been renewed interest in other bacteria that had been observed in animal stomachs as early as late in the nineteenth century. many of these bacteria have now been isolated and have been shown to belong to the same genus, helicobacter, which currently contains nine species. study of the gastric helicobacters is important because it provides relevant information about how bacteria can survive in the gastric environme ... | 1993 | 8449568 |
| therapeutic immunization against helicobacter mustelae in naturally infected ferrets. | helicobacter infection of the gastric antrum is responsible for a number of gastric disorders. antibiotic therapy is lengthy and is not always effective. it has been shown previously that oral immunization against helicobacter felis in mice can prevent colonization after challenge. the aim of this study was to investigate the efficacy of therapeutic immunization in eradicating an established helicobacter infection and in reducing gastritis. | 1996 | 8964402 |
| an uncultured gastric spiral organism is a newly identified helicobacter in humans. | "gastrospirillum hominis" is an uncultivated spiral bacterium in human gastric mucosa that is larger and more tightly coiled than helicobacter pylori. in an attempt to determine if this organism is a new species of helicobacter, its 16s rrna gene was cloned and sequenced. gastric mucosa from 2 patients infected with "gastrospirillum hominis" was fed to specific pathogen-free mice. electron microscopy of gastric tissue confirmed that the mice became colonized with "gastrospirillum hominis." the 1 ... | 1993 | 8335974 |
| demonstration of helicobacter pylori-like organisms in the gastric mucosa of captive exotic carnivores. | samples of gastric tissue from the cardiac, fundic and pyloric region of 30 carnivores comprising 12 tigers (panthera tigris), 10 lions (panthera leo), three pumas (felis concolor), two leopards (panthera pardus), one serval (felis serval), one wolf (canis lupus) and one hyena (crocuta crocuta) kept at german zoological gardens were subjected to histopathological and immunohistochemical examination. selected tissue specimens of 12 animals were examined also by electron microscopy. the purpose of ... | 1997 | 9076597 |
| [mucinase activity of helicobacter pylori: application of simplified mucinase test]. | we conducted the simplified mucinase tests about helicobacters (helicobacter pylori, helicobacter felis and helicobacter mustelae) and campylobacter jejuni, positive controls were pseudomonas maltophilia and pseudomonas cepacia. h. pylori, h. felis and c. jejuni showed low resolution activities for hog gastric mucin, however h. mustelae had no detectable the activities. this enzymatic activity varies considerably by cultural condition of h. pylori, therefore it is difficult to compare the activi ... | 1993 | 8283626 |
| novel intranasal immunization techniques for antibody induction and protection of mice against gastric helicobacter felis infection. | intranasal (i.n.) delivery of antigen can be highly effective for generating circulating and secretory antibody responses. mice were immunized i.n. with two antigens, human iga, and helicobacter pylori urease in the presence or absence of mucosal adjuvant. to restrict antigen delivery to the upper airways, protein solutions were administered in a small volume without anesthesia. repeated daily i.n. administration of antigen without adjuvant elicited high levels of specific igg in serum and iga i ... | 1997 | 9141207 |
| long term infection of the gastric mucosa with helicobacter species does induce atrophic gastritis in an animal model of helicobacter pylori infection. | gastric atrophy is a precursor lesion in the development of gastric cancer. it has been proposed that atrophy is part of a natural progression of inflammatory changes that result from long term infection with the bacterium helicobacter pylori. the aim of this study was to test this hypothesis using an animal model of human helicobacter infection. conventional mice were infected with either a cat isolate of helicobacter felis or a human isolate of "gastrospirillum hominis". all infected mice show ... | 1993 | 8280955 |
| immunisation against gastric infection with helicobacter species: first step in the prophylaxis of gastric cancer? | the discovery of the gastric bacterium, helicobacter pylori and the demonstration of its role in the pathogenesis of gastroduodenal disease, has been one of the major microbiological advances in the last decade. recent demonstration of long term infection with this bacterium as a risk factor in gastric carcinoma suggests that intervention in a disease of major morbidity and mortality is possible. using a model of helicobacter infection in mice it has been shown that oral immunisation with a soni ... | 1993 | 8280938 |
| lack of protection against gastric helicobacter infection following immunisation with jack bean urease: the rejection of a novel hypothesis. | the common mucosal immune system was stimulated by oral immunisation with jack bean urease and the adjuvant cholera toxin. a high level of local antibody and serum antibody was induced in mice following hyperimmunisation with this combination. no cross-reacting antibody was found against either helicobacter pylori or helicobacter felis. no protection was observed against oral challenge of immunised mice with living h. felis thus disproving the interesting hypothesis of pallen and clayton that pl ... | 1994 | 8181696 |
| animal models and vaccine development. | following the demonstration of helicobacter pylori as a major gastroduodenal pathogen there was a need to develop animal models in order to investigate mechanisms of pathogenesis and to be able to test new treatment strategies. helicobacter pylori will only colonize a limited number of hosts including non-human primates, germ-free or barrier raised piglets, germ-free dogs and recently laboratory raised cats. although these models have proved useful there is a need for more convenient small anima ... | 1995 | 8563056 |
| culture and characteristics of helicobacter bizzozeronii, a new canine gastric helicobacter sp. | organisms whose cells were large, tight spirals were isolated from gastric biopsies of dogs. touch cytology samples from all of the dogs contained large spiral organisms. characteristics of 10 strains are described. these organisms were 5 to 10 microns long by 0.3 microns wide, and each cell had 10 to 20 sheathed flagella at both ends of the cell. the cells did not have periplasmic fibrils. these organisms were microaerophilic and grew at 37 and 42 degrees c but not at 25 degrees c on brain hear ... | 1996 | 8573490 |
| local and systemic immune responses in murine helicobacter felis active chronic gastritis. | helicobacter felis inoculated per os into germfree mice and their conventional non-germfree counterparts caused a persistent chronic gastritis of approximately 1 year in duration. mononuclear leukocytes were the predominant inflammatory cell throughout the study, although polymorphonuclear cell infiltrates were detected as well. immunohistochemical analyses of gastric mucosa from h. felis-infected mice revealed the presence of mucosal b220+ cells coalescing into lymphoid follicles surrounded by ... | 1993 | 8500873 |
| structure-activity relationship of omeprazole and analogues as helicobacter pylori urease inhibitors. | helicobacter pylori urease belongs to a family of highly conserved urea-hydrolyzing enzymes. a common feature of these enzymes is the presence of two lewis acid nickel ions and a reactive cysteine residue in the active site. the h+/k(+)-atpase inhibitor omeprazole is a prodrug of a sulfenamide which covalently modifies cysteine residues on the luminal side of the h+/k(+)-atpase of gastric parietal cells. omeprazole and eight analogues were selected based on their chemical, electronic, and kineti ... | 1995 | 8523404 |
| helicobacter infections in laboratory animals: a model for gastric neoplasias? | evidence is rapidly accumulating that helicobacter pylori is a major risk factor for human gastric adenocarcinomas and all low-grade b-cell gastric lymphomas. given this, there is a need to develop animal models with a view to discovering not only how carcinogenesis is initiated, but also how the process can be prevented. the lack of h. pylori animal models suitable for long-term studies means that alternatives are needed. the most productive models are likely to be the helicobacter mustelae-inf ... | 1995 | 8541035 |
| role of the host in pathogenesis of helicobacter-associated gastritis: h. felis infection of inbred and congenic mouse strains. | in humans, helicobacter pylori establishes a chronic infection which can result in various degrees of gastric inflammation, peptic ulcer disease, and a predisposition to gastric cancer. it has been suggested that bacterial virulence factors such as the vacuolating toxin (vaca) and the cytotoxin-associated gene product (caga) may play a major role in determining the clinical outcome of helicobacter infections. the role of host responses in these varied outcomes has received little attention. heli ... | 1996 | 8557346 |
| atrophic gastric changes in both helicobacter felis and helicobacter pylori infected mice are host dependent and separate from antral gastritis. | the role of host factors has been neglected in studies of the pathogenesis of helicobacter associated disease. the aim of this study was to assess the response of different mouse strains to infection with a single strain of helicobacter felis. | 1996 | 9026476 |
| properties of the p-type atpases encoded by the copap operons of helicobacter pylori and helicobacter felis. | the cop operons of helicobacter pylori and helicobacter felis were cloned by gene library screening. both operons contain open reading frames for a p-type ion pump (copa) with homology to cd2+ and cu2+ atpases and a putative ion binding protein (copp), the latter representing a copz homolog of the copyzab operon of enterococcus hirae. the predicted copa atpases contained an n-terminal gmxcxxc ion binding motif and a membrane-associated cpc sequence. a synthetic n-terminal peptide of the h. pylor ... | 1998 | 9440521 |
| mice are protected from helicobacter pylori infection by nasal immunization with attenuated salmonella typhimurium phopc expressing urease a and b subunits. | live salmonella typhimurium phopc bacteria were tested as mucosal vaccine vectors to deliver helicobacter pylori antigens. the genes encoding the a and b subunits of h. pylori urease were introduced into s. typhimurium phopc and expressed under the control of a constitutive tac promoter (tac-ureab) or a two-phase t7 expression system (ct7-ureab). both recombinant salmonella strains expressed the two urease subunits in vitro and were used to nasally immunize balb/c mice. the plasmid carrying ct7- ... | 1998 | 9453612 |
| evaluation of experimental therapeutics in a new mouse model of helicobacter felis utilizing 16s rrna polymerase chain reaction for detection. | a new mouse model of helicobacter felis infection, which mimics the human infection observed with h. pylori, has recently been developed utilizing polymerase chain reaction (pcr) based on the 16s rrna gene sequence for detection of infection. | 1997 | 9140149 |
| neither interleukin-6 nor inducible nitric oxide synthase is required for clearance of chlamydia trachomatis from the murine genital tract epithelium. | female mice bearing targeted mutations in the interleukin-6 or inducible nitric oxide synthase locus mounted effective immune responses following vaginal infection with chlamydia trachomatis. chlamydial clearance rates, local th1 cytokine production, and host antibody responses were similar to those of immunocompetent control mice. therefore, neither gene product appears to be critical for the resolution of chlamydial infections of the urogenital epithelium. | 1998 | 9488425 |
| helicobacter pylori porcdab and oordabc genes encode distinct pyruvate:flavodoxin and 2-oxoglutarate:acceptor oxidoreductases which mediate electron transport to nadp. | helicobacter pylori, a major cause of human gastric disease, is a microaerophilic bacterium that contains neither pyruvate nor 2-oxoglutarate dehydrogenase activity. previous studies (n. j. hughes, p. a. chalk, c. l. clayton, and d. j. kelly, j. bacteriol. 177:3953-3959, 1995) have indicated that the major routes for the generation of acetyl coenzyme a (acetyl-coa) and succinyl-coa are via pyruvate:flavodoxin oxidoreductase (por) and 2-oxoglutarate:acceptor oxidoreductase (oor), respectively. th ... | 1998 | 9495749 |
| local immunoglobulin g antibodies in the stomach may contribute to immunity against helicobacter infection in mice. | orogastric immunization of mice with helicobacter antigens, together with a mucosal adjuvant (cholera toxin), has been shown to confer immunity in the helicobacter felis infection model. the aim of the study was to investigate the humoral immune responses associated with immunity and to compare these with responses in h. felis-infected mice. | 1997 | 9207277 |
| the endotoxin of helicobacter pylori is a modulator of host-dependent gastritis. | atrophic gastritis caused by helicobacter pylori is the precursor lesion in the development of intestinal-type gastric adenocarcinoma. in animal models, atrophic gastritis induced by helicobacter felis has been shown to be host dependent, developing in some mouse strains and not in others. the lipopolysaccharide (lps) of h. pylori has been suggested to play a role in the induction of gastritis. the goal of this study was to compare the inflammation induced by long-term infection of the c3h/he an ... | 1997 | 9234792 |
| antimicrobial activity of novel furanonaphthoquinone analogs. | analogs of furanonaphthoquinone (fnq) from tecoma ipe mart had mics ranging from 1.56 to 25 microg/ml against gram-positive bacteria. fnq showed significantly lower mics against methicillin-resistant staphylococcus aureus than against methicillin-sensitive s. aureus. fnq inhibited helicobacter pylori with an mic of 0.1 microg/ml. fungi, including pathogenic species, were sensitive to fnq with mics similar to those of amphotericin b. | 1998 | 9517956 |
| pepsinogen c gene product is a possible growth factor during gastric mucosal healing. | we isolated, by the subtraction cloning method, a pepsinogen c (pgc) gene fragment (the sequence between the 968th and 1179th base pairs) from a rat gastric mucosal cdna library as a cdna clone encoding a substance that promotes growth of the normal rat gastric mucosal cell line rgm1. northern blot analysis revealed that pgc gene expression was enhanced not only in acetic acid-induced chronic gastric ulcers but also in indomethacin-induced gastric mucosal lesions. pgc gene expression was also in ... | 1997 | 9299443 |
| mice carrying a truncated apc gene have diminished gastric epithelial proliferation, gastric inflammation, and humoral immunity in response to helicobacter felis infection. | helicobacter pylori infection and adenomatous polyposis coli (apc) gene mutations have been linked to gastric cancer in humans, but possible synergistic interaction(s) between these risk factors have not been examined. fourteen c57bl/6 wild-type and 14 apc1638 heterozygous mice were inoculated with helicobacter felis at 6 weeks of age and compared at various time points with a similar number of uninfected control mice of the same genotype. both infected and uninfected apc1638 mice had a limited ... | 1997 | 9307281 |
| the helicobacter felis ftsh gene encoding an atp-dependent metalloprotease can replace the escherichia coli homologue for growth and phage lambda lysogenization. | cloning and sequencing of an approximately 6.0-kb chromosomal dna fragment from helicobacter felis revealed five complete open reading frames. the deduced amino acid sequence of one orf exhibited sequence similarity to the ftsh protein, an atp-dependent metalloprotease, from various bacterial species. the encoded protein consists of 638 amino acid residues with a molecular mass of 70.2 kda. the hydropathy profile of the ftsh protein predicted two n-terminal transmembrane regions that were confir ... | 1998 | 9560419 |
| gastritis in urease-immunized mice after helicobacter felis challenge may be due to residual bacteria. | oral immunization with recombinant helicobacter pylori urease (rure) coadministered with a mucosal adjuvant protects mice against challenge with helicobacter felis. in this study, the duration of protection and gastritis after challenge were characterized at sequential time intervals up to 1 year. | 1997 | 9322506 |
| helicobacter salomonis sp. nov., a canine gastric helicobacter sp. related to helicobacter felis and helicobacter bizzozeronii. | during a study of the prevalence and distribution of gastric helicobacters in domestic pets, a novel group of helicobacter-like organisms were identified. these "helicobacter group 2" strains were initially distinguished from the species helicobacter felis and helicobacter bizzozeronii by their cellular morphology and the type of motility exhibited. bacterial cells were only slightly spiral, 5 to 7 microns long, and 0.8 to 1.2 microns wide and showed an unusual slow wavelike motion. each cell ha ... | 1997 | 9336895 |
| vaccine strategies for prevention of helicobacter pylori infection. | to examine the level and duration of the humoral immune response to helicobacter felis following oral immunization or infection. | 1995 | 8574728 |
| canine gastritis associated with helicobacter felis. | naturally occurring gastritis associated with helicobacter felis was detected in two dogs. histologically, chronic changes characterized by lymphofollicular aggregation were observed. ultrastructurally, organisms located on the mucosal surface, within gastric pits and glandular epithelial cells. h. felis was isolated and urease activity was detected in all areas of the stomachs. | 1995 | 8591747 |
| [efficiency of microbank systems for the conservation of microorganisms relevant to veterinary medicine and others which are not easy to cultivate]. | in this paper the conservation of different bacteria, yeasts and molds from diagnostic material was examined with a commercial deep freeze system. 137 bacteria isolated from the stomachs of dogs, cats and pigs and from duodenal juice of cats and 7 isolates of yeasts and fungi from diagnostic material were conserved with the deep freeze system microbank-tm (mast diagnostica). furthermore 62 helicobacter pylori-isolates and 1 helicobacter felis-isolate were conserved with this system. after a stor ... | 1995 | 8593139 |
| rectal and intranasal immunizations with recombinant urease induce distinct local and serum immune responses in mice and protect against helicobacter pylori infection. | to determine the optimal inductive sites for immunization against helicobacter pylori infection, the protective efficacy of recombinant urease (rure) was assessed for mice given the vaccine by either the oral (p.o.), intranasal (i.n.), or rectal route. when mice were immunized with rure (25 microg p.o. or rectally or 10 microg i.n.) plus heat-labile toxin from escherichia coli as the mucosal adjuvant, all routes afforded protection against challenge with h. pylori, as indicated by a significant ... | 1998 | 9596763 |
| carbon-14-urea breath test as a noninvasive method to monitor helicobacter felis colonization in mice. | we have developed a 14c-urea breath test to follow the course of helicobacter felis infection in mice. peak 14co2 production occurred approximately 8 min after substrate administration. the test values were compared to those from a rapid urease test and correlated with the presence of pathogens by histology. the sensitivity was 99%, specificity 91%, positive predictive value 95% and negative predictive value 99% when the assay was conducted in fasted mice. we conclude that in mice the breath tes ... | 1996 | 8626045 |
| helicobacter-specific cell-mediated immune responses display a predominant th1 phenotype and promote a delayed-type hypersensitivity response in the stomachs of mice. | studies regarding the nature of cell-mediated immunity in helicobacter pylori infection and its role in pathogenesis have yielded controversial results. to address this issue in a controlled manner, we have employed the well-characterized helicobacter felis-mouse model. immunized/challenged and nonimmunized/infected mice were evaluated for cellular proliferation, gastric inflammation, and cytokine and ab production at various times after infection. we observed two types of cell-mediated immune r ... | 1996 | 8648119 |
| il-6-deficient mice exhibit normal mucosal iga responses to local immunizations and helicobacter felis infection. | using il-6-deficient (il-6 -/-) or wild-type mice, we investigated whether il-6 is involved in the intestinal adjuvant activity of cholera toxin (ct) and to what extent il-6 is required for mucosal iga responses against soluble protein ags or live helicobacter felis infection. in naive il-6 -/- mice we found normal total iga levels in serum, bronchial and intestinal lavage and unaltered frequencies of iga plasma cells in intestinal lamina propria. in peyer's patches (pp) and mesenteric lymph nod ... | 1996 | 8666800 |
| inhibition of class ii major histocompatibility complex antigen processing by escherichia coli heat-labile enterotoxin requires an enzymatically active a subunit. | escherichia coli heat-labile enterotoxin (lt) and cholera toxin (ct) were found to inhibit intracellular antigen processing. processing was not inhibited by mutant lt with attenuated adp-ribosyltransferase activity, ct b or lt b subunit, which enhanced presentation of preexisting cell surface peptide-class ii major histocompatibility complex complexes. inhibition of antigen processing correlated with a subunit adp-ribosyltransferase activity. | 1998 | 9632629 |
| the helicobacter felis mouse model in assessing anti-helicobacter therapies and gastric mucosal prostaglandin e2 levels. | the aims of the present study were to assess the usefulness of the helicobacter felis mouse model in the evaluation of antimicrobial therapies and the effect of helicobacter infection on gastric mucosal prostaglandin e2 release. | 1996 | 8726299 |
| biochemical aspects of helicobacter pylori colonization of the human gastric mucosa. | unlike helicobacter felis and other helicobacter species of animal origin, helicobacter pylori colonizes the lower gastric mucin layer of the stomach and adheres to human gastric epithelial cells. it is still an open question if h. pylori can interact with specific glycoconjugates in the gastric mucin layer. it is possible that colonization of the oral cavity is a first step of a complex infectious process. most likely resting or slow growing cells of h. pylori interact with lewis blood group su ... | 1996 | 8730256 |
| helicobacter felis as a cofactor alone or together with stress in cryptosporidial activation in mice. | cryptosporidiosis is caused by a protozoan parasite, mainly found in animals, which usually results in transient, mild gastroenteritis in humans but can cause severe and prolonged disease in immunocompromised individuals. immunocompetent mice, naturally infected with cryptosporidium muris, were used to investigate the effects of inoculation with helicobacter felis and of stress on the activity of the c. muris infection, as indicated by histopathological examination of their stomachs. the results ... | 1995 | 8746615 |
| a sensitive and specific pcr method to detect helicobacter felis in a conventional mouse model. | although many detection methods have been used to determine helicobacter colonization in small animal models, the sensitivity and specificity of these detection methods are limited. to improve the helicobacter felis conventional mouse model for accurate evaluation of therapeutic regimens, we developed a pcr for detection of, and a competitive pcr for quantitation of, h. felis in viral antibody-free (vaf) mice. the pcr was based on the h. felis 16s rrna gene. an internal control dna was used for ... | 1996 | 8770507 |
| occurrence and topographical mapping of gastric helicobacter-like organisms and their association with histological changes in apparently healthy dogs and cats. | the occurrence and topographical mapping of the gastric helicobacter-like organisms (ghlos) and their association with histological changes were studied in apparently healthy dogs and cats. multiple samples were collected for histological examination from the fundus, corpus and antrum of the stomach of 10 dogs and 10 cats. fundus and corpus were also sampled for transmission electron microscopy (three dogs, six cats), and for culture (eight dogs, six cats). in all dogs, ghlos were detected in th ... | 1996 | 8779805 |
| prevalence and varieties of helicobacter species in dogs from random sources and pet dogs: animal and public health implications. | gastric bacteria of a variety of ultrastructural morphologies have been identified in or isolated from domestic carnivores, but their prevalence in different populations of animals and their clinical significance are still unknown. the purposes of this study were (i) to evaluate the prevalence and morphologic types of gastric bacterial in three different populations of dogs; (ii) to determine which of the organisms were culturable, and if the cultured organisms were morphologically similar to th ... | 1996 | 8940465 |
| vaccination against helicobacter pylori. | the initial steps have been taken towards the development of a vaccine against the human gastroduodenal pathogen, helicobacter pylori. proof of principle was achieved when mice were protected against challenge with living helicobacter felis, a close relative of the human pathogen, following oral immunization with h. felis sonicate and the mucosal adjuvant, cholera toxin. similar results with h. pylori antigen have allowed development of possible human vaccines. recombinant urease protein has bee ... | 1996 | 8959525 |
| morphological diversity of cultured canine gastric helicobacter spp. | the cell morphology, the number of flagella, the occurrence of periplasmic fibrils and ultrastructural structures of five groups of cultured canine gastric helicobacter spp. were compared. the study included four strains of helicobacter felis, four strains of helicobacter bizzozeronii, one strain of 'flexispira', six strains of an unnamed spiral organism 2 and one strain of an unnamed spiral organism 3 which were isolated from gastric biopsies. cultures were studied with negative staining, trans ... | 1997 | 9481513 |
| detection and prevalence of helicobacter infection in pet cats. | the presence of spiral bacteria in the feline stomach has been recognized for over a century, but the identities and degrees of prevalence of such organisms in privately owned cats are still poorly documented. the aims of this study were (i) to adapt different diagnostic tools and evaluate their practicality for diagnosing feline gastric helicobacter colonization, (ii) to determine the prevalence of gastric helicobacter-like organisms in pet cats, (iii) to identify the feline species, and (iv) t ... | 1998 | 9508286 |
| mice lacking secretory phospholipase a2 show altered apoptosis and differentiation with helicobacter felis infection. | infection with helicobacter pylori uniformly leads to a chronic superficial gastritis that may progress to atrophic gastritis, a premalignant process. a mouse model of helicobacter felis infection was used to study possible genetic determinants of the response to infection. | 1998 | 9516388 |
| immune responses of specific-pathogen-free mice to chronic helicobacter pylori (strain ss1) infection. | a model permitting the establishment of persistent helicobacter pylori infection in mice was recently described. to evaluate murine immune responses to h. pylori infection, specific-pathogen-free swiss mice (n = 50) were intragastrically inoculated with 1.2 x 10(7) cfu of a mouse-adapted h. pylori isolate (strain ss1). control animals (n = 10) received sterile broth medium alone. animals were sacrificed at various times, from 3 days to 16 weeks postinoculation (p.i.). quantitative culture of gas ... | 1998 | 9529052 |
| gastrin release and gastric acid secretion in the rat infected with either helicobacter felis or helicobacter heilmannii. | helicobacter pylori infection in humans has been shown to be associated with changes in gastric physiology, including exaggerated basal and meal-stimulated gastrin levels. this has been suggested to be due to the direct effects of the bacterium through inflammation and its urease enzyme. the gastric bacteria helicobacter felis and helicobacter heilmannii colonize the antrum of rats in large numbers and induce no significant inflammatory response. thus, the direct effect of helicobacter infection ... | 1998 | 9737579 |
| isolation and identification of helicobacter spp. from canine and feline gastric mucosa. | it is known that virtually all healthy adult dogs and cats harbor spiral helicobacters in their gastric mucosa. three species, helicobacter felis, helicobacter bizzozeronii, and helicobacter salomonis have been isolated in vitro from the gastric mucosa of these animals. the aims of this study were to evaluate the efficacy of an isolation method for canine and feline gastric helicobacters that has been developed at the university of helsinki; to estimate the prevalence and distribution of these t ... | 1998 | 9758832 |
| scid/ncr mice naturally infected with helicobacter hepaticus develop progressive hepatitis, proliferative typhlitis, and colitis. | hepatitis, proliferative typhlitis, and colitis were characterized in young adult and older scid/ncr mice naturally infected with helicobacter hepaticus. liver lesions consisted of kupffer, ito, and oval cell hyperplasia along with multifocal to coalescing coagulative hepatocyte necrosis. numerous warthin-starry-positive bacteria were observed in the parenchyma, and there were minimal to mild accumulations of monocytic cells and neutrophils. proliferative typhlitis was characterized by moderate ... | 1998 | 9784560 |
| antrum- and corpus mucosa-infiltrating cd4(+) lymphocytes in helicobacter pylori gastritis display a th1 phenotype. | in this study, cytokine patterns produced by cd4(+) t cells isolated from antrum or corpus gastral biopsy specimens of 10 patients with helicobacter pylori-positive gastritis were compared. to this end, expression of intracellular cytokines (interleukin-4 [il-4] and gamma interferon) and of cd4 was assessed by flow cytometry. ten to 60% of the isolated cd4(+) t cells produced gamma interferon upon stimulation. with the exception of one patient, il-4-positive cd4(+) cells were not detected. there ... | 1998 | 9784570 |
| antagonistic activity against helicobacter infection in vitro and in vivo by the human lactobacillus acidophilus strain lb. | the purpose of the present study was to examine the activity of the human lactobacillus acidophilus strain lb, which secretes an antibacterial substance(s) against helicobacter pylori in vitro and in vivo. the spent culture supernatant (scs) of the strain lb (lb-scs) dramatically decreased the viability of h. pylori in vitro independent of ph and lactic acid levels. adhesion of h. pylori to the cultured human mucosecreting ht29-mtx cells decreased in parallel with the viability of h. pylori. in ... | 1998 | 9797324 |
| identification of a novel enteric helicobacter species in a kitten with severe diarrhea. | a previously undescribed helicobacter sp. was recovered from a cat with severe diarrhea. based upon the absence of any other identifiable cause of diarrhea, this helicobacter may be involved in the development of the disease signs. the organism could not be cultured but was described on the basis of 16s rrna gene sequence analysis and morphology and appeared to be a new species, with helicobacter canis being the most genetically similar species. the presence of a diarrhea-inducing helicobacter i ... | 1998 | 9542907 |
| lack of protection following immunisation with h. pylori outer membrane vesicles highlights antigenic differences between h. felis and h. pylori. | helicobacter pylori-induced inflammation is associated with the development of gastritis, peptic ulcer disease and gastric cancer in humans. immunisation against this bacterium would ultimately have a major impact on h. pylori-related disease, notably global gastric cancer rates. to date, several potential h. pylori vaccine candidates have been identified. in this study, the helicobacter felis/murine model was used to assess the immunogenicity of a previously undescribed h. pylori outer membrane ... | 1998 | 9561729 |
| presence of multiple "helicobacter heilmannii" strains in an individual suffering from ulcers and in his two cats. | circumstantial evidence suggests that "helicobacter heilmannii" infection is an example of zoonosis. the presence of "h. heilmannii" strains in a human subject with acute gastric erosions, in his two cats, and in two unrelated cats was analyzed, and the genetic relatedness of the human and feline strains was assessed. a 580-bp, pcr-amplified sequence of "h. heilmannii" urease b gene (ureb) obtained from biopsies from the human subject and his two cats was restricted with alui and cloned for sequ ... | 1998 | 9574707 |
| rapid development of severe hyperplastic gastritis with gastric epithelial dedifferentiation in helicobacter felis-infected il-10(-/-) mice. | interleukin (il)-10 is a potent anti-inflammatory and immune-regulatory cytokine. mice deficient in il-10 production (il-10(-/-)) develop a spontaneous inflammatory bowel disease, indicating that il-10 is an important regulator of the mucosal immune response in vivo. to study the role of il-10 in the host response to gastric helicobacter infection, stomachs of il-10(-/-) and wild-type mice were colonized with helicobacter felis, as a model of human h. pylori infection. within 4 weeks of h. felis ... | 1998 | 9588906 |
| experimental helicobacter pylori infection induces antral gastritis and gastric mucosa-associated lymphoid tissue in guinea pigs. | humans infected with helicobacter pylori have abnormally low levels of the antioxidant vitamin c, which protects against the formation of carcinogenic nitrosamines, in gastric juice. guinea pigs, like humans and nonhuman primates, have a dietary requirement for vitamin c. as such, these species have gastrointestinal vitamin c transport systems not found in other animals. we have developed and characterized a guinea pig model of chronic gastric h. pylori infection with the rodent-adapted sydney s ... | 1998 | 9596724 |
| antibody-secreting cells in the stomachs of symptomatic and asymptomatic helicobacter pylori-infected subjects. | in this study we analyzed whether infection with helicobacter pylori gives rise to specific b-cell responses against a number of putative virulence factors of h. pylori, e.g., urease, flagellin, and different bacterial surface antigens, locally in the gastric mucosa. this was studied in antrum and corpus biopsies collected from 11 h. pylori-infected patients with duodenal ulcers, 11 asymptomatic h. pylori carriers, and 13 noninfected, healthy controls. mononuclear cells were isolated from the bi ... | 1998 | 9596737 |
| specific antibodies in sera and gastric aspirates of symptomatic and asymptomatic helicobacter pylori-infected subjects. | in this study we have determined systemic and local antibody responses against different helicobacter pylori antigens in h. pylori-infected and noninfected subjects. in addition, we studied whether differences in antibody responses between patients with duodenal ulcers and asymptomatic h. pylori carriers might explain the different outcomes of infection. sera and in most instances gastric aspirates were collected from 19 duodenal ulcer patients, 15 asymptomatic h. pylori carriers, and 20 noninfe ... | 1998 | 9605978 |
| mycoplasma contamination of canine gastric biopsy samples and cultures of gastric helicobacter spp. | helicobacter felis and h. bizzozeronii are canine gastric helicobacters related to h. pylori. the growth of gastric helicobacters requires a complex medium including blood and serum. we found that some of our blood agar cultures were contaminated with mycoplasmas, which were isolated from one biopsy sample and several blood agar cultures of canine gastric helicobacters by pcr or culture method. however, none of our other 18 helicobacter strains, subcultured 10-15 times since 1990, were found to ... | 1998 | 9879925 |
| antigen-dependent progression of mucosa-associated lymphoid tissue (malt)-type lymphoma in the stomach. effects of antimicrobial therapy on gastric malt lymphoma in mice. | in humans, low-grade b-cell mucosa-associated lymphoid tissue (malt) lymphomas of the stomach regress when helicobacter pylori infection is cured by antimicrobial therapy. using an animal model of human gastric malt lymphoma, we observed the effects of helicobacter felis eradication and the relationship between infection and disease progression. antimicrobial therapy was given to one-half of the balb/c mice infected with h. felis for 20 months. groups of antibiotic-treated and untreated mice wer ... | 1998 | 9626066 |
| effectiveness of a vaccine composed of heat-killed candida albicans and a novel mucosal adjuvant, lt(r192g), against systemic candidiasis. | the incidence of fungal infections caused by the opportunistic yeast candida albicans has increased significantly in recent years. the ability to vaccinate selected patients against the organism would be advantageous. in this paper we describe a potential anti-c. albicans vaccine consisting of heat-killed c. albicans (hk-ca) in combination with the novel mucosal adjuvant lt(r192g), a genetically detoxified form of the heat-labile toxin of enterotoxigenic escherichia coli. groups of male cba/j mi ... | 1999 | 9916097 |
| chronic active hepatitis induced by helicobacter hepaticus in the a/jcr mouse is associated with a th1 cell-mediated immune response. | helicobacter hepaticus infection in a/jcr mice results in chronic active hepatitis characterized by perivascular, periportal, and parenchymal infiltrates of mononuclear and polymorphonuclear cells. this study examined the development of hepatitis and the immune response of a/jcr mice to h. hepaticus infection. the humoral and cell-mediated t helper immune response was profiled by measuring the postinfection (p.i.) antibody response in serum, feces, and bile and by the production of cytokines and ... | 1998 | 9632578 |
| catalase, a novel antigen for helicobacter pylori vaccination. | the efficacy of an orogastric vaccine comprised of purified helicobacter pylori catalase plus the mucosal adjuvant cholera toxin (ct) was examined with both the helicobacter felis and h. pylori mouse models with balb/c mice. native h. pylori catalase (200 microg) plus ct was initially used as a vaccine antigen in the h. felis mouse model and protected 80% (8 of 10) of the challenged animals, while all control animals were infected (20 of 20). in a follow-up experiment, recombinant h. pylori cata ... | 1997 | 9353048 |
| characterization of a culturable "gastrospirillum hominis" (helicobacter heilmannii) strain isolated from human gastric mucosa. | spiral organisms were isolated from an antral gastric mucosal biopsy specimen from a dyspeptic patient with gastritis. only corkscrew-shaped organisms resembling "gastrospirillum hominis" ("helicobacter heilmannii") but no helicobacter pylori-like organisms were seen in histological sections. h. pylori was not cultured from specimens from this patient. on the basis of biochemical reactions, morphology, ultrastructure, and 16s dna sequencing, the isolated "g. hominis" was shown to be a true helic ... | 1999 | 10074528 |
| murine cd4 t-cell response to helicobacter infection: th1 cells enhance gastritis and th2 cells reduce bacterial load. | previous findings suggest that th1 cellular immune responses contribute to helicobacter-associated gastritis. to further investigate this issue, interleukin 4 gene targeted mice were infected with helicobacter felis, and a series of adoptive transfer experiments was performed to evaluate the role of both th1 and th2 cells. | 1997 | 9394724 |