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| 2. |
- Holmberg, Martin, et al.
(författare)
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Evaluation of human seroreactivity to Bartonella species in Sweden
- 1999
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Ingår i: Journal of Clinical Microbiology. - 0095-1137 .- 1098-660X. ; 37:5, s. 1381-1384
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Tidskriftsartikel (refereegranskat)abstract
- Among the species that compose the expanding genus Bartonella, thus far only B. henselae and B. quintana have reportedly been isolated from humans in Europe. To evaluate the prevalence of Bartonella infection in Sweden,we conducted a retrospective serological examination of 126 human serum samples. These samples were analyzed for antibodies to B. henselae, B. quintana, and B. elizabethae, Serum samples from 100 blood donors, who spanned the ages of 20 to 60 and had no apparent clinical signs of illness, were also studied as a control group. An immunoglobulin G indirect fluorescence antibody assay revealed 4 and 8.3% Bartonella positivity rates for the blood donor and patient group, respectively, when a cutoff titer of greater than or equal to 64 was chosen. Among the blood donors, four were seropositive to B, elizabethae; one of these also had concordant positive titer to B. henselae, In the patient group, 14 serum samples were positive against Bartonella spp, These serum specimens represented nine patients. In three of these seropositive patients, paired serum samples displayed a fourfold increase in antibody titer to at least one of the three antigens, These three patients are discussed. In this report we also present a case study of a 60-year-old Swedish male with fatal myocarditis, Postmortem serological analysis revealed a high titer against B. elizabethae, PCR and nucleotide sequencing of the myocardial tissue from this patient, and of Liver tissue from one of the other three patients, showed sequences similar to B. quintana, The age, geographical origin, animal contacts, and serological response pattern to the different Bartonella antigens differed among the four patients. This study substantiates the presence of Bartonella spp, in Sweden, documents the seroreactivity to three Bartonella antigens in Swedish patients, and reports the first two cases of B. quintana-like infections in Sweden.
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| 3. |
- Akre, Olof, et al.
(författare)
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Epstein-Barr virus and cytomegalovirus in relation to testicular-cancer risk : a nested case-control study
- 1999
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Ingår i: International Journal of Cancer. - 0020-7136 .- 1097-0215. ; 82:1, s. 1-5
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Tidskriftsartikel (refereegranskat)abstract
- An infectious etiology of testicular cancer has been suggested. We have evaluated seroreactivity against cytomegalovirus (CMV) and Epstein-Barr virus (EBV) in relation to testicular-cancer risk in a case-control study, nested within a cohort of prospectively collected serum specimens from 293,692 individuals. For each of 81 cases of testicular cancer identified, 3 controls were randomly selected from the cohort. Serum IgG antibody titers against CMV and EBV were determined using enzyme-linked immunosorbent assays (ELISAs) and immunofluorescence methods. Odds ratios (OR) were obtained from conditional logistic-regression models. No association was found between CMV positivity and testicular cancer overall (OR = 1.08; 95% confidence interval 0.60-1.94); risk for testicular seminoma was increased among CMV seropositive [OR = 1.70 (0.80-3.59)], whereas seropositivity was associated with decreased risk for testicular non-seminoma [OR = 0.54 (0.19-1.56)] (p for heterogeneity, 0.09). For EBV, the risk for testicular cancer was increased among individuals seropositive for viral capsid antigen (VCA) [OR = 2.74 (0.62-12.12)]. The results lend some support to the hypothesis of an infectious etiology, and we propose that future studies should take into account age at infection.
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| 5. |
- Atuma, Christer, et al.
(författare)
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Extracts of Helicobacter pylori reduce gastric mucosal blood flow through a VacA- and CagA-independent pathway in rats
- 1998
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Ingår i: Scandinavian Journal of Gastroenterology. - : Informa UK Limited. - 0036-5521 .- 1502-7708. ; 33:12, s. 1256-1261
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Helicobacter pylori may interfere with gastroduodenal protective mechanisms. Such effects could be due to a direct interaction with gastric epithelial cells but also to the action of a wide range of secreted and membrane-bound virulence factors. Our aim was to study the acute effects of water extracts produced from H. pylori on gastric mucosal blood flow and acid secretion and to relate them to VacA and CagA activity.METHOD: Extracts were produced from strains 88-23 and A5, both wild type; A5VacA, an isogenic mutant lacking expression of the vacuolating cytotoxin (VacA) and the immunodominant antigen (CagA); and Escherichia coli strain ATCC-25922. Bacterial extracts were applied on the exteriorized gastric corporal mucosa in inactin-anaesthetized rats after removal of as much as possible of the mucus layer, during intravital microscopy. Blood flow was measured by means of laser-Doppler flowmetry.RESULTS: All H. pylori extracts, including the extract from 88-23 heated to 100 degrees C for 30 min, significantly reduced blood flow by 15%-19%, whereas E. coli had no significant effect on blood flow.CONCLUSION: A factor or a combination of factors, other than VacA and CagA released from H. pylori, might compromise the natural defence of the gastric corporal mucosa by reducing mucosal blood flow. The factor is heat-stable and lacking or less potent in E. coli.
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| 6. |
- Atuma, C, et al.
(författare)
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Helicobacter pylori extracts reduce gastric mucosal blood flow by a nitric oxide-independent but mast cell- and platelet-activating factor receptor-dependent pathway in rats
- 1999
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Ingår i: Scandinavian Journal of Gastroenterology. - : Informa UK Limited. - 0036-5521 .- 1502-7708. ; 34:12, s. 1183-1189
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: We have previously shown that water extracts from Helicobacter pylori reduce gastric mucosal blood flow by approximately 15%. It has also been suggested that H. pylori can inhibit endogenous nitric oxide (NO) biosynthesis. Our aim was to examine whether the reduction in blood flow induced by H. pylori is the direct consequence of an NO synthase inhibition and the possible involvement of mast cell degranulation.METHODS: A water extract was produced from wildtype strain 88-23. The extract was applied on the exteriorized gastric corporal mucosa in inactin-anesthetized rats, after removing as much as possible of the mucus layer, during intravital microscopy. Blood flow was measured with laser-Doppler flowmetry.RESULTS: In rats pretreated with the NO synthase inhibitor N-nitro-L-arginine there was a 19% +/- 6% reduction in blood flow 40 min after application of the extract, and a 27% +/- 9% reduction after another 20 min with saline. The reduction was abolished by concomitant pretreatment with the mast cell stabilizer ketotifen or the platelet-activating factor (PAF) receptor antagonist WEB2086.CONCLUSION: The reduction in mucosal blood flow induced by the extract was probably mediated through an acute inflammatory response involving mast cell degranulation with consequent PAF secretion. The effect on blood flow was not the result of a decrease in vascular tone due to an inhibition of endogenous NO biosynthesis.
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| 8. |
- Hjelm, Eva, et al.
(författare)
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Assay of antibiotic susceptibility of Chlamydia pneumoniae
- 1997
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Ingår i: Scandinavian Journal of Infectious Diseases. Supplementum. - 0300-8878 .- 1651-2502. ; 104, s. 13-14
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Tidskriftsartikel (refereegranskat)abstract
- It is well known that treatment of Chlamydia pneumoniae infections is difficult. High doses and prolonged treatment is often needed to achieve clinical cure despite good in vitro effect of the drugs used. We here discuss different methodological problems in the determination of MIC and MBC values of C. pneumoniae. The length of the preincubation time and the lack of fluctuation of the antibiotic concentrations may affect the outcome of the currently used assay.
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| 10. |
- Nyström-Rosander, Christina, et al.
(författare)
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Susceptibility of Chlamydia pneumoniae to azithromycin and doxycycline : methodological aspects on thedetermination of minimal inhibitory andminimal bactericidal concentrations
- 1997
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Ingår i: Scandinavian Journal of Infectious Diseases. - : Informa UK Limited. - 0036-5548 .- 1651-1980. ; 29:5, s. 513-516
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Tidskriftsartikel (refereegranskat)abstract
- An in vitro assay for measuring and comparing the efficacy of different antimicrobial agents against Chlamydia pneumoniae was developed. Azithromycin, a representative of the new azalide group of antibiotics, and doxycycline were evaluated with respect to their antibacterial effect and capacity for intracellular killing under different experimental conditions. For both study drugs, the minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) values increased significantly with longer bacterial preincubation time. The effect of different exposure times of antibiotics on the bacteria was also studied.
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