Specific-pathogen-free conditions enhance inflammatory bowel disease in T-cell receptor knockout, but not C3H/HeJBir mice.
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Animals↗
Biomedical subjects
J G Fox
Publications and source records attributed to J G Fox.
Helicobacter bilis/Helicobacter rodentium co-infection associated with diarrhea in a colony of scid mice.
An outbreak of diarrhea spanning 3 months occurred in a breeding colony of scid/Trp53 knockout mice. Approximately a third of the 150 mice were clinically affected, with signs ranging from mucoid or watery diarrhea to severe hemorrhagic diarrhea with mortality. Helicobacter bilis and the newly recognized urease-negative organism H. rodentium were isolated from microaerobic culture of feces or cecal specimens from affected mice. Dual infection with H. bilis and H. rodentium were confirmed by culture and polymerase chain reaction (PCR) in several animals. Both Helicobacter species rapidly colonized immunocompetent sentinel mice exposed to bedding from cages containing affected mice, but the sentinel remained asymptomatic. Mice with diarrhea had multifocal to segmental proliferative typhlitis, colitis, and proctitis. Several affected mice had multifocal mucosal necrosis with a few focal ulcers in the cecum, colon, and rectum. Mice with diarrhea were treated with antibiotic food wafers (1.5 mg of amoxicillin, 0.69 mg of metronidazole, and 0.185 mg of bismuth/mouse per day) previously shown to eradicate H. hepaticus in immunocompetent mice. Antibiotic treatment resulted in resolution of diarrhea, but not eradication of H. bilis and H. rodentium; mice continued to have positive PCR results after a 2-week treatment regimen, and clinical signs of diarrhea returned in some mice when treatment was suspended. To the authors' knowledge, this is the first report of natural infection with either H. bilis and/or H. rodentium causing acute diarrheal disease and suggests that H. bilis and/or H. rodentium can be an important pathogen for scid mice.
Animals↗
Immunophenotypic characterization of lymphomas from the mediastinum of young ferrets.
OBJECTIVE: To determine the phenotype of naturally developing lymphomas in young ferrets. ANIMALS: 10 ferrets with lymphoma. PROCEDURE: Neoplastic tissues were graded histologically according to the National Cancer Institute's Working Formulation for non-Hodgkin's lymphoma and phenotype was determined by means of immunohistochemical staining. A polyclonal anti-human CD3 and a monoclonal anti-human CD79 antibody were used to classify the lymphomas in situ as T-cell or B-cell origin. Specificity of antibodies was determined by evaluating lymphoid tissue from normal ferrets in situ, which was confirmed by western blot analyses. RESULTS: All 10 ferrets had clinically aggressive tumors, irrespective of the phenotype. Nine ferrets had T-cell lymphoma that extensively involved the mediastinum. Remnants of thymic tissue, indicative of thymic origin, were identified in lymphoma of these 9 ferrets. One ferret had a B-cell multicentric lymphoma without involvement of the mediastinum. CONCLUSIONS: The majority of lymphomas in these young ferrets involved the mediastinum and were of T-cell phenotype. Impact for Human Medicine-There are many similarities between the lymphoma syndrome of ferrets and the condition documented for cats and children with lymphoma of the mediastinal area. CLINICAL RELEVANCE: Differential diagnoses for young ferrets with clinical signs of lethargy or respiratory distress should include T-cell lymphoma of the mediastinum.
Animals↗
Insertion of internal jugular temporary hemodialysis cannulae by direct ultrasound guidance--a prospective comparison of experienced and inexperienced operators.
OBJECTIVE: Previous studies have shown that inexperienced operators have a lower success rate than experienced operators for insertion of internal jugular cannulae using the anatomical landmark technique. The object of this study was to determine the rate of successful insertion, incidence of immediate complications and incidence of infection for temporary hemodialysis cannulae inserted under ultrasound guidance by experienced and inexperienced operators. METHODS: The reason for insertion, patient age, reason for failed insertion, immediate complications, duration of cannula survival and reason for removal were recorded prospectively for 107 attempted cannulations by 7 operators in 72 subjects with renal failure. Operators were defined as "experienced" (more than 3 years postgraduate clinical experience and more than 25 previous central vein cannulae inserted) or "inexperienced" (less than 3 years postgraduate clinical experience and less than 3 previous central vein cannulae inserted). Rates of successful cannulation and incidence of complications were compared for experienced and inexperienced operators. Cannula survival without infection was analysed by Kaplan-Meier survival for experienced and inexperienced operators. RESULTS: The overall success rate of cannula insertion at first site was 103/107 (96.3%) with no difference between experienced and inexperienced operators (56/58 vs. 47/49). 103 internal jugular temporary haemodialysis cannulae were inserted into 72 subjects. The only immediate complication was incorrect positioning of the cannula in 6 cases requiring manipulation. The median survival of hemodialysis cannulae was 14 days (range 1-111). 64.1% cannulae functioned for as long as required. Of the remainder, 33/36 were removed because of presumed cannula related infection. There was no difference in the median duration of cannula survival between experienced and inexperienced operators (15 days versus 12 days; Mann-Whitney point estimate = -1.00; 95% confidence interval -6.00, 3.00). p = 0.66) or in the probability of cannula survival without infection by Kaplan Meier analysis. CONCLUSION: We conclude that ultrasound guided temporary haemodialysis cannulation is a safe procedure with a high rate of success, the success rate for inexperienced operators is much higher than previous studies of cannulation using the anatomical landmark technique and the rate of cannula removal due to infection is not influenced by operator experience.
Catheterization, Central Venous↗
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 incidence of atypical proliferation foci in the mucosa of the antrum and pyloric junction at 4.5 and 6 months of age, whereas polyps of the antrum and pylorus were present in all mice, regardless of infection status, at 7.5 months. In contrast, no altered gastric mucosal foci were observed in control or infected C57BL/6 mice at any time point. Interestingly, the infected Apc1638 mice had less epithelial proliferation and inflammation in the body of the stomach, lower anti-H. felis serum IgG antibody responses (although both the wild-type and Apc mutant mice had a Th1-like immune response, based on a predominantly IgG2a immunoglobulin response), and higher bacteria and urease scores than did infected wild-type C57BL/6 mice. In conclusion, the Apc1638 truncating mutation leads to gastric dysplasia and polyposis of the antrum and pyloric junction, but H. felis infection of the Apc mutant mouse does not lead to an increased rate of gastric neoplasia. In addition, our data suggest this Apc mutation may actually lead to decreased immune, inflammatory, and gastric hyperplastic responses to Helicobacter infection, suggesting the possibility of a novel role for this tumor suppressor gene in the immune and local tissue responses to gastric bacterial infection.
Adenomatous Polyposis Coli Protein↗
Acute inferior vena cava thrombosis in a patient with membranous nephropathy treated by rt-PA lysis.
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Adult↗
Helicobacter rodentium sp. nov., a urease-negative Helicobacter species isolated from laboratory mice.
A spiral-shaped bacterium with bipolar, single, nonsheathed flagella was isolated from the intestines of laboratory mice. The organism grew at 37 and 42 degrees C under microaerobic and anaerobic conditions, did not hydrolyze urea, was weakly positive for catalase and oxidase, reduced nitrate to nitrite, did not hydrolyze indoxyl acetate or hippurate, and was resistant to cephalothin and nalidixic acid. This is the first urease-negative, murine Helicobacter spp. isolated from intestines. Also, Helicobacter pullorum and this bacterium are unique among the genus Helicobacter in having nonsheathed flagella. The new bacterium appears to be part of the normal intestinal flora; although its pathogenic potential is unknown, this organism was also isolated from scid mice with diarrhea that were co-infected with Helicobacter bilis. On the basis of 16S rRNA gene sequence analysis data and biochemical and phenotypic criteria, the new organism is classified as a novel helicobacter, for which we propose the name Helicobacter rodentium. The type strain is MIT 95-1707 (= ATCC 700285).
Animals↗
Promotion of ulcerative duodenitis in young ferrets by oral immunization with Helicobacter mustelae and muramyl dipeptide.
BACKGROUND: The purpose of this study was to determine whether oral immunization of ferret kits with a whole-cell sonicate of Helicobacter mustelae lysate (Hml) and the adjuvant muramyl dipeptide (MDP) would reduce the incidence of natural colonization with H. mustelae and the extent of Helicobacter-associated gastritis by enhancing the host mucosal immune response. MATERIALS AND METHODS: Between the ages of 4 and 11 weeks, 44 ferret kits were gavaged with Hml and various doses of MDP. The extent of gastritis and duodenitis and the immune response to H. mustelae were evaluated. RESULTS: All kits became colonized naturally with H. mustelae and the majority developed mild to severe gastritis and duodenitis. Kits that received Hml with MDP developed significantly greater inflammation of the gastric antrum and duodenum, as compared to kits vaccinated with Hml alone. Vaccination with Hml and 50 micrograms of MDP was associated with severe lesions in the proximal duodenum characterized by accumulation of mononuclear inflammatory cells, mucosal erosion, and ulceration. Although serum antibody specific for H. mustelae in 4-week-old kits was approximately 50% of adult levels, a finding attributable to passively acquired maternal antibody, both systemic and mucosal antibody levels became depressed over time despite oral vaccination. The humoral immune response was sufficiently low to prevent detection of any significant dose effect of MDP on antibody levels among experimental groups. CONCLUSIONS: Oral vaccination of young ferrets with Hml and 50 micrograms MDP increased the risk of Helicobacter-associated mucosal ulceration in the proximal duodenum, which was associated with low humoral (but significant cell-mediated) immune responses to H. mustelae. In retrospect, the frequency of vaccination may have suppressed the systemic humoral immune response, thereby promoting mucosal damage by H. mustelae. The 50-microgram dose of MDP enhanced the cell-mediated immune response, which indirectly contributed to development of severe lesions. The increased frequency of mucosal damage associated with this vaccination regimen enhances the value of the ferret model for studying duodenal ulceration secondary to Helicobacter infection.
Acetylmuramyl-Alanyl-Isoglutamine↗
Helicobacter bilis-induced inflammatory bowel disease in scid mice with defined flora.
Helicobacter bilis has been isolated from aged inbred mice with multifocal chronic hepatitis and from scid mice with diarrhea, proliferative typhlitis, and colitis. To determine the pathogenic potential of H. bilis, we inoculated 4-week-old female Tac:Icr:Ha(ICR)-scidfDF mice by intraperitoneal injection of approximately 10(8) CFU of H. bilis in phosphate-buffered saline (PBS) (n = 15) or PBS alone (n = 10) and necropsied them at 7 weeks postinfection. Sham-inoculated mice had no significant gross or histopathological findings. In contrast, all 15 experimentally inoculated mice (confirmed to be H. bilis-colonized by culture and PCR of cecal contents) exhibited varying degrees of inflammatory bowel disease (IBD). Proliferative typhlocolitis was characterized by focal to segmental areas of crypt hyperplasia and a predominantly histiocytic inflammatory cell infiltrate. Labeling indices for 5-bromo-2'-deoxyuridine incorporation were increased approximately 2.5-fold in the ceca and colons of H. bilis-inoculated mice. This is the first study to demonstrate experimentally that infection with H. bilis causes IBD in scid mice with defined flora. This result both confirms a pathogenic role for H. bilis in mice and provides a new model relating a specific microbial agent and IBD.
Animals↗
Infection of the ferret stomach by isogenic flagellar mutant strains of Helicobacter mustelae.
Helicobacter mustelae, like Helicobacter pylori, possesses two flagellin proteins, FlaA and FlaB. Isogenic mutant strains of H. mustelae have been constructed by disruption of the flaA or flaB gene with a kanamycin resistance cassette or by introduction of both a kanamycin and a chloramphenicol resistance gene to produce a double mutant. To determine whether one or both flagellin proteins are necessary for colonization and persistence of infection with H. mustelae, 19 ferrets, specific pathogen free for H. mustelae, were given either the HMF1 flaA::km (weakly motile), ATCC 43772 flaB::km (moderately motile), or HMF1 flaA::cat flaB::km (non-motile) mutant strain, the wild-type parent strains, or sterile broth. Gastric tissue samples were obtained during sequential gastric biopsies beginning at 3 weeks postinoculation and ending at necropsy at 3 months postinoculation. H. mustelae infection status was determined by culture, histology, and serology. The wild-type parent strains of H. mustelae infected all ferrets at all time points. The double-mutant strain was unable to colonize; the flaA and flaB single-mutant strains were able to initially colonize at a low level and establish persistent infection with increasing numbers of organisms over time. The severity of gastritis produced by infection with these strains of H. mustelae correlated with the number of organisms present in the gastric mucosa. Flagellar motility is an important virulence factor for colonization and pathogenesis in the H. mustelae ferret model.
Animals↗
Inflammatory bowel disease: an immunity-mediated condition triggered by bacterial infection with Helicobacter hepaticus.
Inflammatory bowel disease (IBD) is thought to result from either an abnormal immunological response to enteric flora or a normal immunological response to a specific pathogen. No study to date has combined both factors. The present studies were carried out with an immunologically manipulated mouse model of IBD. Mice homozygous for the severe combined immunodeficiency (scid) mutation develop IBD with adoptive transfer of CD4+ T cells expressing high levels of CD45RB (CD45RB(high) CD4+ T cells). These mice do not develop IBD in germfree conditions, implicating undefined intestinal flora in the pathogenesis of lesions. In controlled duplicate studies, the influence of a single murine pathogen, Helicobacter hepaticus, in combination with the abnormal immunological response on the development of IBD was assessed. The combination of H. hepaticus infection and CD45RB(high) CD4+ T-cell reconstitution resulted in severe disease expression similar to that observed in human IBD. This study demonstrates that IBD develops in mice as a consequence of an abnormal immune response in the presence of a single murine pathogen, H. hepaticus. The interaction of host immunity and a single pathogen in this murine system provides a novel model of human IBD, an immunity-mediated condition triggered by bacterial infection.
Animals↗
Diagnosis of Helicobacter pylori infection in a colony of rhesus monkeys (Macaca mulatta).
Twenty-three young adult rhesus monkeys from China were evaluated for the presence of Helicobacter pylori. Gastric body and antral biopsy samples were tested for H. pylori by PCR analysis, culture, rapid urease testing, and histologic evaluation. Serologic testing to detect H. pylori immunoglobulin G (IgG) antibodies was performed by using a commercially available human-based enzyme-linked immunosorbent assay (ELISA) test and an ELISA test which utilized homologous H. pylori antigens and an anti-rhesus IgG conjugate. PCR analysis with H. pylori-specific 26-kDa protein primers detected H. pylori in 21 of the 23 rhesus monkeys (91%). Culture testing identified the organism in 12 of the 23 animals (52%). Rapid urease tests were positive for all animals. H. pylori was diagnosed by histological examination in 11 of 23 monkeys (48%). Of the 21 monkeys positive for H. pylori by PCR, only 3 (14%) had positive results by the commercial ELISA test, yielding a sensitivity of 14%, a specificity of 100%, and an accuracy of 22%. However, 19 of the 21 PCR-positive animals (90%) had positive results by the ELISA test with homologous rhesus H. pylori antigen and anti-monkey conjugate, with predicted index values greater than or equal to 0.7 considered positive and values between 0.5 and 0.7 considered equivocal. This test had a sensitivity of 90%, a specificity of 100%, and an accuracy of 91%. Therefore, the ELISA test with rhesus monkey origin components was more accurate for detecting infected animals than the human-based ELISA.
Animals↗
Use of pulsed-field gel electrophoresis to determine genomic diversity in strains of Helicobacter hepaticus from geographically distant locations.
In 1992 a helical microorganism associated with chronic active hepatitis and a high incidence of hepatocellular tumors was identified in the hepatic parenchyma of A/JCr mice. By using biochemical tests, phenotypic characterization, and 16S rRNA gene sequence analysis, the organism was classified as a novel Helicobacter species and named Helicobacter hepaticus. Recent surveys completed in our laboratory indicate that H. hepaticus is widespread in academic and commercial mouse colonies. The aim of this study was to examine the H. hepaticus genome by pulsed-field gel electrophoresis (PFGE) to determine the degree of genomic variation and genomic size. This technique has been used to identify significant genomic diversity among strains of Helicobacter pylori and to demonstrate only slight genomic diversity among strains of Helicobacter mustelae. Genomic DNAs from 11 isolates of H. hepaticus from the United States, Germany, France, and The Netherlands were subjected to PFGE after digestion with SmaI. Isolates from three independent sources within the United States had very similar PFGE patterns, suggesting that the genomic DNAs of these isolates are conserved. Genomic DNA isolated from a fourth source within the United States had a PFGE pattern different from those of the other U.S. isolates. Isolates obtained from Germany, France, and The Netherlands had PFGE patterns that differed markedly from those of the U.S. isolates and from one another. The use of DNA fingerprinting may be useful in subsequent epidemiological studies of H. hepaticus when the source and method of spread of this murine pathogen need to be ascertained. By PFGE, the genomic size of H. hepaticus is estimated to be roughly 1.3 Mb, which compares to 1.67 Mb for H. pylori and 1.7 Mb for H. mustelae.
Animals↗
Helicobacter mustelae-associated gastric adenocarcinoma in ferrets (Mustela putorius furo).
Helicobacter pylori in humans is associated with active, chronic gastritis, peptic ulcer disease, and most recently has been linked epidemiologically to gastric adenocarcinoma. A related organism, Helicobacter mustelae, naturally infects ferrets and also causes a persistent gastritis, a precancerous lesion, and focal glandular atrophy of the proximal antrum. In this report, we document the clinical presentation and histopathologic confirmation of H. mustelae-associated gastric adenocarcinoma in two middle-aged male ferrets. The ferret appears to be well suited to study the pathogenesis of naturally occurring Helicobacter sp.-induced gastric adenocarcinoma.
Adenocarcinoma↗
Helicobacter mustelae-associated gastric MALT lymphoma in ferrets.
Gastric lymphoma resembling gastric mucosa-associated lymphoid tissue (MALT) lymphoma linked with Helicobacter pylori infection in humans was observed in ferrets infected with H. mustelae. Four ferrets with ante- or postmortem evidence of primary gastric lymphoma were described. Lymphoma was diagnosed in the wall of the lesser curvature of the pyloric antrum, corresponding to the predominant focus of H. mustelae induced gastritis in ferrets. Two ferrets had low-grade small-cell lymphoma and two ferrets had high-grade large-cell lymphoma. Gastric lymphomas demonstrated characteristic lymphoepithelial lesions, and the lymphoid cells were IgG+ in all ferrets. Lymphoma was confirmed by light chain restriction, which contrasted with the 1.2:1 kappa lambda ratio observed in H. mustelae-associated chronic gastritis. H. mustelae infection in ferrets has been used as a model for gastritis, ulcerogenesis, and carcinogenesis. The ferret may provide an attractive model to study pathogenesis and treatment of gastric MALT lymphoma in humans.
Animals↗
Distribution of technetium 99m-labeled red blood cells during isoflurane anesthesia in ferrets.
OBJECTIVE: To address the physiologic mechanism of isoflurane-associated reduction in hematologic variables in ferrets. ANIMALS: 6 young adult female ferrets. PROCEDURE: Distribution of 99mTc-labeled autologous erythrocytes was measured by serial in vivo imaging. Data were recorded in 4 ferrets, using a gamma camera, immediately prior to anesthesia, 15 minutes after 2% isoflurane anesthesia in O2 via endotracheal tube, 1 minute prior to and throughout a 10-minute phenylephrine infusion, 20 and 40 minutes after termination of the phenylephrine infusion, and 45 minutes after termination of anesthesia. Blood indices were also measured at times that paralleled those for imaging. One ferret served as a conscious control (no anesthetic administration), and another as an isoflurane control (no phenylephrine administration). RESULTS: In ferrets under anesthesia, splenic radioactivity increased from baseline of 10.2 +/- 2.0% to 38.4 +/- 3.2% (mean +/- SEM; P < 0.05) of the injected dose. Splenic radioactivity decreased to 13.4 +/- 3.8% of the injected dose during phenylephrine infusion and to near baseline for the recovery image. Splenic radioactivity in the conscious control remained constant throughout the study, whereas that of the anesthetized control was persistently increased throughout administration of isoflurane. Percentage reduction of the 15-minute sample values, compared with baseline values for all hematologic indices, was: RBC count, 33% (P < 0.05); hemoglobin concentration, 34% (P < 0.05); hematocrit, 35% (P < 0.05); and plasma protein concentration, 20% (P < 0.05). All RBC variables returned to within 7 to 14% of baseline by 45 minutes after termination of anesthesia. CONCLUSION: Isoflurane anesthesia causes splenic sequestration of RBC in ferrets that is partially reversed by phenylephrine infusion or termination of anesthesia. Thus, investigators and clinicians should be cautious when interpreting hematologic findings in isoflurane-anesthetized ferrets, and accordingly, fluid treatment and transfusion should be planned.
Anesthesia, Inhalation↗
The expanding genus of Helicobacter: pathogenic and zoonotic potential.
The microbial flora of stomachs of humans and animals have been the focus of considerable research since the discovery that Helicobacter pylori in humans caused a variety of gastric diseases. Other Helicobacter species have now been isolated from the stomachs of various mammals, including dogs, cats, ferrets, pigs, monkeys, and cheetahs, all of which are associated with various degrees of gastritis in their hosts. Helicobacter species have also been isolated from the intestinal tracts of humans, animals, and birds. Helicobacter species have not only been isolated from intestines of mice but have, in addition, been isolated from diseased livers of inbred and outbred mice, and one of these, H hepaticus is linked to liver tumors. H canis and H pullorum isolated from dogs and chickens, respectively, have also been cultured from feces of diarrheic humans. H fennelliae and H cinaedi are two additional helicobacters primarily associated with lower bowel disease in immunocompromised humans. To date, there are at least 13 formally named species of the new genus, Helicobacter, the majority being proven or suspected gastrointestinal or hepatic pathogens. Several of these helicobacters have zoonotic potential as well. It is predicted that additional Helicobacter species will be identified, and they, too, may be important pathogens in humans and animals.
Acinonyx↗
The role of Helicobacter species in newly recognized gastrointestinal tract diseases of animals.
Because Helicobacter pylori is now known to be a significant human pathogen, experimental animal models are increasingly being used to study the pathogenesis of this organism. Unfortunately, early studies failed to establish H. pylori in animal models, and surprisingly, Koch's postulates were initially fulfilled in two human volunteers. Germfree experiments performed in pigs and pups however established that H. pylori would colonize in these animals, and gastritis was induced. Certain macaque species and cats are now known to be naturally infected with H. pylori, and these animals are susceptible to experimentally induced infection with the organism as well. Interestingly, as the ability to manipulate and grow H. pylori in vitro increased, so did the ability to colonize it in animal models. Helicobacter pylori has now experimentally induced gastritis in germfree euthymic and nude mice and in conventionally housed mice. Six additional Helicobacter species have been isolated and identified from the stomachs of various mammals, including dogs, cats, ferrets, pigs, monkeys, and cheetahs; these organisms, similar to H. pylori, are associated with variable degrees of gastritis in their hosts. In addition to the discovery of gastric helicobacters, an increasing number of Helicobacter spp. have been isolated from the distal part of the gastrointestinal tracts of mammals and birds. Importantly, in one inbred strain of mice, A/JCr, persistent infection with H. hepaticus is linked to development of hepatic adenomas and adenocarcinomas. To date, the genus Helicobacter includes 17 named species as well as other formally unnamed closely related organisms. An overview of gastric helicobacters and naturally acquired Helicobacter spp.-induced disease in laboratory animals and, where appropriate, use of animal models to study H. pylori-associated gastric disease is presented. Similarities between Helicobacter infections and the epidemiology of the diseases induced by these bacteria in humans and animals also are highlighted.
Animals↗