| 1. |
- Nilsson, Ingrid, et al.
(författare)
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Helicobacter ganmani infection associated with a spontaneous outbreak of inflammatory bowel-like disease in an IL-10-deficient mouse colony
- 2008
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Ingår i: Scandinavian Journal of Laboratory Animal Science. - 0901-3393. ; 35:1, s. 13-24
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Tidskriftsartikel (refereegranskat)abstract
- Background: A breeding colony of IL-10 deficient B6.129P2-Il10(tmICgn/J) mice, kept under conventional conditions, developed an inflammatory bowel-like disease (IBD) with rectal prolapse and blood tinged diarrhoea. No clinical signs of disease were observed at the time of arrival to our animal house. These animals were originally planned to serve as a negative control group in an experimental infection study with Helicobacter species to investigate colonization of the murine gut. Results: A spiral-shaped, Gram-negative bacterium was isolated from the breeding mice colony. In a first group of six animals, tissue specimens from the liver, small and large intestines, faeces and blood, were analysed by culture, PCR-denaturing gradient gel electrophoresis (PCR-DGGE), species-specific PCR assays and DNA-sequencing, histology and serology. Helicobacter ganmani, but no other Helicobacter species, was isolated from the liver, small bowel, caecum, colon and faeces. We found inflammation in caeca, colon and livers, most pronounced in the caecal areas of culture positive mice with a severe typhlitis with cystic dilatation of glandular structures and irregular crypt architecture. Some animals showed a pronounced colitis with mucosal and sub-mucosal inflammatory infiltrates. Other animals displayed large lymphoid infiltrates in the livers and hepatitis. Tissue samples and sera from 18 additional animals from the same breeding colony were analysed by the same methods, except for culture. H. ganmani was identified by PCR in most tissue samples of the 18 additional animals as well. Sero-conversion to H. ganmani correlated well with histopathological changes. Conclusions: Our findings emphasize the importance of using Helicobacter-free animals to develop murine models of chronic hepatitis and colitis.
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| 2. |
- Papadogiannakis, Nikos, et al.
(författare)
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Modes of adherence of Helicobacter pylori to gastric surface epithelium in gastroduodenal disease: A possible sequence of events leading to internalisation
- 2000
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Ingår i: APMIS : acta pathologica, microbiologica, et immunologica Scandinavica. - : Wiley. - 1600-0463 .- 0903-4641. ; 108:6, s. 439-447
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Tidskriftsartikel (refereegranskat)abstract
- We have investigated various modes of adherence of Helicobacter pylori to the human gastric epithelium, using transmission electron microscopy, in biopsies from nine patients with peptic ulcer disease and from four patients with chronic active gastritis. H. pylori was demonstrated in abundance in all cases within the surface mucous layer. In all ulcer- and in one out of four gastritis patients H. pylori was shown in close proximity to the gastric epithelium, with concurrent alterations in the configuration of microvilli and the apical cytoplasmic region of gastric cells. Previously described modes of H. pylori adherence were confirmed, such as loose attachment with fibrillar-like strands, firm attachment with pedestal formation, invasion in the intercellular spaces, and invagination with cup formation. Moreover, in many cases a fusion between the bacterial outer layer and gastric cell membranes was evident. In four cases (31; three with active and one with past ulcer disease) viable H. pylori was found in the cytoplasm of gastric mucous cells. Our results support the hypothesis that the different modes of adherence of H. pylori represent a stepwise, possibly sequential, process which in a significant number of cases leads to internalisation of the organism. The invariable occurrence of adhesion and more frequent internalisation of H. pylori in ulcer patients may suggest a link with the pathogenesis of peptic ulcer disease.
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| 3. |
- Sjunnesson, Håkan, et al.
(författare)
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Comparative study of Helicobacter pylori infection in guinea pigs and mice - elevation of acute-phase protein C3 in infected guinea pigs
- 2001
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Ingår i: Pathogens and Disease. - 2049-632X. ; 30:2, s. 167-172
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Tidskriftsartikel (refereegranskat)abstract
- Eighteen Dunkin-Hartley guinea pigs and 50 NMRI mice were inoculated with Helicobacter pylori and the infection followed by culture, histopathology, antibody response, and plasma levels of the acute-phase proteins albumin, C3, and transferrin for up to 7 weeks. The immune response to H. pylori surface proteins was studied by an enzyme immunoassay (EIA) and Western immunoblot and the plasma levels of albumin, C3, and transferrin were analyzed by single radial immunodiffusion. Guinea pigs had a more severe gastritis and a higher EIA immune response than NMRI mice. Serum C3 levels were elevated in infected guinea pigs after 3 and 7 weeks indicating a systemic inflammatory response and a possible link between H. pylori infection and extragastric manifestations such as vasculitis associated with atherosclerosis. Serum cholesterol levels were analyzed in guinea pigs at 7 weeks and indicated a higher level in H. pylori-infected than in control animals, but this difference was not statistically significant.
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| 4. |
- Wang, Xin, et al.
(författare)
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Astaxanthin-rich algal meal and vitamin C inhibit Helicobacter pylori infection in BALB/cA mice
- 2000
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Ingår i: Antimicrobial Agents and Chemotherapy. - 1098-6596. ; 44:9, s. 2452-2457
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Tidskriftsartikel (refereegranskat)abstract
- Helicobacter pylori infection in humans is associated with chronic type B gastritis, peptic ulcer disease, and gastric carcinoma. A high intake of carotenoids and vitamin C has been proposed to prevent development of gastric malignancies. The aim of this study was to explore if the microalga Haematococcus pluvialis rich in the carotenoid astaxanthin and vitamin C can inhibit experimental H. pylori infection in a BALB/cA mouse model. Six-week-old BALB/cA mice were infected with the mouse-passaged H. pylori strain 119/95. At 2 weeks postinoculation mice were treated orally once daily for 10 days (i) with different doses of algal meal rich in astaxanthin (0.4, 2, and 4 g/kg of body weight, with the astaxanthin content at 10, 50, and 100 mg/kg, respectively), (ii) with a control meal (algal meal without astaxanthin, 4 g/kg), or (iii) with vitamin C (400 mg/kg). Five mice from each group were sacrificed 1 day after the cessation of treatment, and the other five animals were sacrificed 10 days after the cessation of treatment. Culture of H. pylori and determination of the inflammation score of the gastric mucosae were used to determine the outcome of the treatment. Mice treated with astaxanthin-rich algal meal or vitamin C showed significantly lower colonization levels and lower inflammation scores than those of untreated or control-meal-treated animals at 1 day and 10 days after the cessation of treatment. Lipid peroxidation was significantly decreased in mice treated with the astaxanthin-rich algal meal and vitamin C compared with that of animals not treated or treated with the control meal. Both astaxanthin-rich algal meal and vitamin C showed an inhibitory effect on H. pylori growth in vitro. In conclusion, antioxidants may be a new strategy for treating H. pylori infection in humans.
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| 5. |
- Wang, Xin, et al.
(författare)
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Development of high-grade lymphoma in Helicobacter pylori-infected C57BL/6mice
- 2000
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Ingår i: APMIS : acta pathologica, microbiologica, et immunologica Scandinavica. - : Wiley. - 1600-0463. ; 108:7-8, s. 503-508
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Tidskriftsartikel (refereegranskat)abstract
- Helicobacter pylori infection is associated with chronic gastritis, peptic ulcer disease, gastric adenocarcinoma and MALT lymphoma. Mice with H. pylori infection develop severe gastritis and atrophic changes in their stomachs after 6 months. We followed H. pylori -infected animals for 13 months to find out whether dysplasia, carcinoma or lymphoma developed. Six-week-old C57BL/6 mice were infected with the CagA-positive and VacA-positive H. pylori mouse-passaged strain 119/95, fed a low antioxidant diet, and kept in microisolated cages. Histopathological changes were examined after 13 months' infection. All H. pylori -inoculated mice (n=5) developed a gastric squamous papilloma with nagging of the lamina muscularis after 13 months. Three out of five animals developed high-grade B-cell lymphoma derived from a MALT lymphoma at the squamous-corpus border with manifestations also in the liver, spleen and kidney. There was a suspicion of local gastric lymphoma in the two remaining mice but with no significant changes in the liver, spleen or kidney. The normal control mice showed no pathological changes in any of these organs. It is concluded that this mouse model with infection by the CagA-positive, vac-toxin-producing H. pylori strain 119/95 is suitable for use in the study of lymphoma development and also development of squamous cell papilloma with proliferative features.
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| 6. |
- Wang, Xin, et al.
(författare)
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Two-year follow-up of Helicobacter pylori infection in C57BL/6 and Balb/cA mice.
- 2003
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Ingår i: APMIS : acta pathologica, microbiologica, et immunologica Scandinavica. - : Wiley. - 1600-0463. ; 111:4, s. 514-522
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Tidskriftsartikel (refereegranskat)abstract
- Helicobacter pylori infection is associated with chronic gastritis, peptic ulcer disease, gastric adenocarcinoma and MALT lymphoma. We previously found high-grade lymphoma after 13 months' H. pylori infection in C57BL/6 mice. In this study we followed H. pylori infection by three different isolates in C57BL/6 and Balb/cA mice for 23 months. Six-week-old C57BL/6 and Balb/cA mice were infected with H. pylori strains 119p (CagA+, VacA+), SS1 (CagA+, VacA+) and G50 (CagA-, VacA-). Mice were followed at 2 weeks, 10 weeks and 23 months post-inoculation (p.i.) by culture, histopathology and serology. Strain G50 was only reisolated from mice 2 weeks p.i. There was no difference in colonization between strain 119p and SS1 at 10 weeks p.i., whereas SS1 gave 100% colonization versus 119p gave 50% 23 months p.i.. Interestingly, the inflammation score was higher in mice infected with strain 119p than with SS1 10-week p.i., and there were lymphoepithelial lesions in mice infected with strain 119p and G50 but not with SS1 at 23 months post-infection. Eight mice infected with strains 119p and G50 developed gastric lymphoma (grade 5 and 4). One C57BL/6 mouse infected with strain 119p developed hepatocellular carcinoma after 23 months. Immunoblot showed specific bands of 2633 kDa against H. pylori in infected mice, and two mice infected with strain SSI reacted with antibodies to the 120 kDa CagA toxin. Conclusion: A reproducible animal model for H. pylori-induced lymphoma and possibly hepatocellular carcinoma is described. Strain diversity may lead to different outcomes of H. pylori infection.
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