| 1. |
- Burova, L, et al.
(author)
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Role of group A streptococcal IgG-binding proteins in triggering experimental glomerulonephritis in the rabbit
- 2003
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In: APMIS : acta pathologica, microbiologica, et immunologica Scandinavica. - : Wiley. - 1600-0463. ; 111:10, s. 955-962
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Journal article (peer-reviewed)abstract
- Our previous studies have indicated that the IgG-binding M-family proteins (IgGBP) of group A streptococci may be involved in eliciting experimental acute poststreptococcal glomerulonephritis (APSGN) in the rabbit. These surface proteins were also found to trigger production of anti-IgG, which might conceivably act to enhance renal deposition of immune complexes (IC). In the present study, a clinical isolate of serotype M22 (strain AL168), an isogenic double mutant deficient for both the IgGBPs Mrp and Emm, as well as mutants deficient in only one of the proteins were tested for capacity to induce glomerulonephritis. Streptococci to be used for injecting rabbits were heat-killed. Surface-bound IgG was removed by 1 M KSCN and cells were then repeatedly washed in PBS before use. Rabbits were injected intravenously with 10(9) cells three times a week for 8 weeks and, following one month of rest, for another 6 weeks. Deposits of IgG and C3 as well as induced chemokines TNF-alpha, IL-1beta and IL-6 were traced in cryostat sections using specific antibodies and appropriate peroxidase-labelled anti-antibodies. In four rabbits immunized with the double mutant strain, no deposits were found, and as examined by TEM, only subtle and transient renal changes were observed. In contrast, the original strain AL168 induced pronounced inflammatory and degenerative glomerular changes in all four rabbits injected, and deposits of TNF-alpha, IL-1beta and IL-6 were found in mesangial and endothelial cells. Similar deposits and glomerular changes were seen in all eight rabbits injected with the mrp-emm+ mutant and in four out of seven animals receiving the mrp+emm- mutant. There was a highly significant correlation between high levels of circulating anti-IgG and development of APSGN. These results confirm an important role of streptococcal IgGBP in triggering experimental APSGN as earlier proposed by our group.
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| 2. |
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| 3. |
- Marthinsen, L, et al.
(author)
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Intestinal spirochetosis in eight pediatric patients from Southern Sweden - A clinical, histopathological and ultrastructural study
- 2002
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In: APMIS : acta pathologica, microbiologica, et immunologica Scandinavica. - : Wiley. - 1600-0463. ; 110:7-8, s. 571-579
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Journal article (peer-reviewed)abstract
- Intestinal spirochetes in humans have been recognized for more than a century, but it is still a matter of debate whether they are just commensal organisms or whether they cause colorectal disease. Most descriptions to date are of adult patients, while reports in the pediatric literature have been scarce. In a retrospective study we found eight children with intestinal spirochetosis. The findings, clinical as well as pathological, with light- and electron microscopy, are presented. In all patients, a 3 pm-thick layer of spirochetes was visualised on the luminal aspect of the epithelial cells covering the enterocytes and part of the gland openings. In five of the eight cases an inflammatory cell reaction was seen by light microscopy and in one patient a picture suggesting intracytoplasmatically located spirochetes was seen by electron microscopy. Despite partial or complete destruction of microvilli, spirochetes were still able to adhere to the enterocyte membranes. In three children there was a clear correlation between treatment and relief of symptoms. In four there was partial improvement and in one child no change in bowel-related symptoms. We believe that intestinal spirochetes may cause colorectal disease in children. Possible pathogenic mechanisms are discussed.
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| 4. |
- Melhus, Åsa, et al.
(author)
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A mouse model for acute otitis media
- 2003
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In: Acta Pathologica, Microbiologica et Immunologica Scandinavica (APMIS). - : Wiley. - 0903-4641 .- 1600-0463. ; 111:10, s. 989-994
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Journal article (peer-reviewed)abstract
- To induce acute otitis media in the mouse and to describe the clinical and bacteriological course of the infection, middle ears of BALB/c, Swiss-Webster and C57BL/6 mice were inoculated with Streptococcus pneumoniae, Haemophilus influenzae and Moraxella catarrhalis. Systemic and local changes were monitored by clinical observations, otomicroscopy, and analysis of bacterial samples from blood and middle ears. Agglutination of mouse erythrocytes by M. catarrhalis was also tested. Depending on bacterial strain, bacterial dose, and mouse strain three responses were identified: acute otitis media, otitis media with serous effusion, or no reaction. BALB/c mice were the most susceptible animals. On day 3, 76% of the BALB/c mice had developed middle ear infection, 50% had a positive middle ear culture, 56% were bacteremic, and 10% had succumbed to a disseminated infection. The local infections lasted approximately a week. Animals which survived recovered without permanent deterioration or otomicroscopically discernible changes. In no case did M. catarrhalis induce a culture-positive middle ear infection, possibly due to an inability to agglutinate the mouse erythrocytes. The mouse model can become a useful tool in studies of pneumococcal and H. influenzae-induced otitis media, but the bacterial dose has to be carefully titrated and adjusted to the chosen mouse strain.
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| 5. |
- Sjunnesson, Håkan, et al.
(author)
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Five month persistence of Helicobacter pylori infection in guinea pigs
- 2003
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In: APMIS : acta pathologica, microbiologica, et immunologica Scandinavica. - : Wiley. - 1600-0463. ; 111:6, s. 634-642
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Journal article (peer-reviewed)abstract
- Seven Dunkin-Hartley guinea pigs were infected with the Sydney strain of H. pylori (SS1). Gastric histopathology was evaluated and serum antibody response to H. pylori cell-surface proteins was analysed by enzyme immunoassay (EIA) and immunoblot. Tissue and faecal samples from five control animals were analysed for the presence of naturally occurring Helicobacter spp. infection by culture and Helicobacter genus-specific PCR. The H. pylori infection persisted for 5 months, in most animals accompanied by a histologically severe antral gastritis, exhibiting focal degeneration and necrosis of gastric crypt epithelium. Increased numbers of mitotic figures were observed in the gastric epithelium, indicating a regenerative process. Infected animals displayed specific antibodies towards H. pylori cell-surface proteins in immunoblot, whereas EIA was of dubious value creating false-positive results. Serum complement C3 and cholesterol levels appeared to be elevated in infected animals. Helicobacter spp. infection was not detected in the control animals. The persistent infection, accompanied by severe gastritis and a prominent serum antibody response, and the apparent absence of a natural Helicobacter spp. infection makes the guinea pig model useful in H. pylori research.
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| 6. |
- Wang, Mei, et al.
(author)
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Identification of the translocating bacteria in rats with acute liver injury and their relation to the bacterial flora of the intestinal mucosa
- 2001
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In: APMIS : acta pathologica, microbiologica, et immunologica Scandinavica. - : Wiley. - 1600-0463. ; 109:7-8, s. 551-558
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Journal article (peer-reviewed)abstract
- The bacterial flora of the intestine and the bacteria found in liver, mesenteric lymph nodes, portal and arterial blood after D-galactosamine-induced liver injury, with and without pretreatment with Lactobacillus plantarum DSM 9843, were studied in the rat. Dominating representatives were identified to species level by 16S rDNA sequencing and typed by randomly amplified polymorphic DNA (RAPD) and by restriction endonuclease analysis (REA) for strain definition. It was proven that bacterial strains from the intestine occur at extraintestinal sites after liver injury. Lactobacillus spp. dominated the intestinal flora and were also the most frequently found genus in the liver and the mesenteric lymph nodes. Some of the blood isolates, identified as Staphylococcus aureus, Proteus vulgaris and Bacteroides merdae, were not found as a dominating part of the mucosal flora. Treatment with L. plantarum before liver injury decreased translocation and made the intestinal flora increasingly dominated by lactobacilli.
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| 7. |
- Wang, Xin, et al.
(author)
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Two-year follow-up of Helicobacter pylori infection in C57BL/6 and Balb/cA mice.
- 2003
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In: APMIS : acta pathologica, microbiologica, et immunologica Scandinavica. - : Wiley. - 1600-0463. ; 111:4, s. 514-522
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Journal article (peer-reviewed)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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| 8. |
- Buentke, E, et al.
(author)
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Dendritic cells and fungi
- 2003
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In: APMIS : acta pathologica, microbiologica, et immunologica Scandinavica. - : Wiley. - 0903-4641. ; 111:7-8, s. 789-796
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Journal article (peer-reviewed)
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| 9. |
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| 10. |
- Hoorfar, Jeffrey, et al.
(author)
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Diagnostic PCR: validation and sample preparation are two sides of the same coin
- 2004
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In: APMIS : acta pathologica, microbiologica, et immunologica Scandinavica. - : Wiley. - 1600-0463. ; 112:11-12, s. 808-814
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Research review (peer-reviewed)abstract
- Increased use of powerful PCR technology for the routine detection of pathogens has focused attention on the need for international validation and preparation of official non-commercial guidelines. Bacteria of epidemiological importance should be the prime focus, although a "validation infrastructure" once established could easily be adapted for PCR-based detection of viruses and parasites. The aim of standardization should be the widespread adoption of diagnostic PCR for routine pathogen testing. European experience provides the impetus for realization of this vision through preparation of quantitative reference DNA material and reagents, production of stringent protocols and tools for thermal cycler performance testing, uncomplicated sample preparation techniques, and extensive ring trials for assessment of the efficacy of selected matrix/pathogen detection protocols.
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