| 1. |
- Dahlgren, Ulf, 1953, et al.
(författare)
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Expression of a dietary protein in E. coli renders it strongly antigenic to gut lymphoid tissue.
- 1991
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Ingår i: Immunology. - 0019-2805. ; 73:4, s. 394-7
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Tidskriftsartikel (refereegranskat)abstract
- Bacteria that colonize the intestinal mucosa elicit a strong mucosal immune response, whereas food antigens such as ovalbumin are very weakly immunogenic to the gut-associated lymphoid tissue. This may either be due to special physico-chemical properties of bacterial substances versus proteins from animals and plants, or to stimulating properties of the bacteria on, e.g., antigen presentation, rendering all substances contained within bacteria antigenic. To test these hypotheses, ovalbumin was expressed in wild-type Escherichia coli and germ-free female rats were colonized with this strain. The systemic and mucosal antibody response of these rats was compared with that of rats given large amounts of dietary ovalbumin. Biliary IgA antibodies, which reflect the local IgA antibody production in the intestine, were only found in the rats colonized with ovalbumin-synthesizing E. coli. IgG antibodies in the bile were also only seen in these rats. We conclude that mucosal immunogenicity depends on the context in which a protein is presented to the gut-associated lymphoid tissue, rather than to special antigenic characteristics of the protein in itself.
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| 2. |
- Adlerberth, Ingegerd, 1959, et al.
(författare)
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Intestinal colonization with Enterobacteriaceae in Pakistani and Swedish hospital-delivered infants.
- 1991
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Ingår i: Acta paediatrica Scandinavica. - 0001-656X. ; 80:6-7, s. 602-10
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Tidskriftsartikel (refereegranskat)abstract
- Rectal cultures from Swedish and Pakistani hospital-delivered newborn infants were analysed regarding the early acquisition of enterobacteria. Swedish infants were delivered vaginally, Pakistani infants were delivered either vaginally or by caesarean section. The Swedish infants were all breast-fed, whereas breastfeeding was incomplete and often started late among the Pakistani infants. Both groups of Pakistani infants were more rapidly colonized with enterobacteria than were the Swedish infants. Cultures from Swedish infants seldom yielded more than one kind of enterobacteria; E. coli and Klebsiella were most frequently isolated. E. coli dominated in both Pakistani groups, but especially caesarean section delivered infants were in addition often colonized with Proteus, Klebsiella, Enterobacter or Citrobacter species. Breastfeeding from the first day of life reduced colonization with Klebsiella/Enterobacter/Citrobacter. The results suggest that environmental exposure, delivery mode and early feeding habits all influence the early intestinal colonization with enterobacteria.
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| 3. |
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| 4. |
- Lodinová-Zádníková, R, et al.
(författare)
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The antibody response in breast-fed and non-breast-fed infants after artificial colonization of the intestine with Escherichia coli O83.
- 1991
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Ingår i: Pediatric research. - : Springer Science and Business Media LLC. - 0031-3998 .- 1530-0447. ; 29:4 Pt 1, s. 396-9
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Tidskriftsartikel (refereegranskat)abstract
- The local and systemic antibody response after oral administration of a nonenteropathogenic type 1 fimbriated Escherichia coli O83 strain was followed in nine breast-fed and eight formula-fed infants during their first 15 wk of life. Five breast-fed and six formula-fed infants were followed as controls. E. coli O83 was detected in the stools of colonized infants from d 2 after colonization and persisted in the intestine for up to 26 wk. The percentage of children successfully colonized with E. coli O83 was higher among breast-fed than among formula-fed colonized infants. Also, the O83 bacteria isolated from the breast-fed children had a higher capacity to attach to colonic epithelial cells of the HT-29 cell line than those isolated from bottle-fed infants. E. coli O83 IgA and IgM antibodies estimated by ELISA were significantly elevated in the saliva of colonized as compared with control infants 2-7 wk after colonization. IgA antibodies against O83 were also higher in the stool of colonized formula-fed infants than in formula-fed controls. The results suggest that the mucosal immune system of the newborn infant can be triggered early to produce specific antibodies against bacteria colonizing the intestine.
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| 5. |
- Gustafsson, Lars, et al.
(författare)
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Infectious disease, reproductive effort and the cost of reproduction in birds
- 1994
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Ingår i: Philosophical transactions of the Royal Society of London: Series B. ; :346, s. 1655-1658
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Tidskriftsartikel (populärvet., debatt m.m.)abstract
- Reproductive effort can have profound effects on subsequent performance. Field experiments on the collared flycatcher (Ficedula albicollis) have demonstrated a number of trade-offs between life-history traits at different ages. The mechanism by which reproductive effort is mediated into future reproductive performance remains obscure. Anti-parasite adaptations such as cell-mediated immunity may probably also be costly. Hence the possibility exists of a trade-off between reproductive effort and the ability to resist parasitic infection. Serological tests on unmanipulated collared flycatchers show that pre-breeding nutritional status correlates positively with reproductive success and negatively with susceptibility to parasitism (viruses, bacteria and protozoan parasites). Both immune response and several indicators of infectious disease correlate negatively with reproductive success. Similar relations are found between secondary sexual characters and infection parameters. For brood-size-manipulated birds there was a significant interaction between experimentally increased reproductive effort and parasitic infection rate with regard to both current and future fecundity. It seems possible that the interaction between parasitic infection, nutrition and reproductive effort can be an important mechanism in the ultimate shaping of life-history variation in avian populations.
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| 6. |
- Herías, M V, et al.
(författare)
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Escherichia coli K5 capsule expression enhances colonization of the large intestine in the gnotobiotic rat.
- 1997
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Ingår i: Infection and immunity. - : American Society for Microbiology. - 0019-9567 .- 1098-5522. ; 65:2, s. 531-6
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Tidskriftsartikel (refereegranskat)abstract
- The role of capsule expression in the capacity of Escherichia coli to colonize in the large intestinal environment was studied in a gnotobiotic rat model. The rats were given perorally a mixture of two mutant strains differing in K5 expression. After 2 weeks, the rats were sacrificed, and subsequently intestinal contents, intestinal mucosae, and mesenteric lymph nodes were homogenized and bacterial numbers were quantified. Two E. coli mutant pairs were used, the first pair (972-998) lacking the O-specific side chain and the second pair (973-997) carrying the O75 lipopolysaccharide. The K5+ mutants established themselves at a higher level than the K5- mutants (10(9) versus 10(6) CFU/g [P < 0.001] for the first pair and 10(9) versus 10(8) CFU/g [P < 0.01] for the second pair, respectively). The results were confirmed by serology showing a K5+ phenotype for practically all isolates. The bacterial population associated with the mucosa was similar to that in the luminal contents with respect to the proportions of the respective mutants, and translocation occurred in numbers proportional to the intestinal population densities of the respective mutants. All mutants were able to express type 1 as well as P fimbriae. After colonization, the expression of P fimbriae remained high whereas only a minority of the isolates expressed type 1 fimbriae. The results suggest that capsule expression and P fimbriae enhance intestinal colonization by E. coli and that these virulence factors, by increasing bacterial densities in the intestine, secondarily increase translocation.
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| 7. |
- Ahrné, Siv, et al.
(författare)
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The normal Lactobacillus flora of healthy human rectal and oral mucosa.
- 1998
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Ingår i: Journal of applied microbiology. - 1364-5072. ; 85:1, s. 88-94
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Tidskriftsartikel (refereegranskat)abstract
- The Lactobacillus flora of the rectal and oral mucosa was sampled from 42 healthy volunteers. Species identification was carried out by numerically comparing API 50CH fermentation patterns with type strains, using an SJ-similarity cut-off level of 79%. For the largest groups, identity was further confirmed by DNA-DNA hybridizations against the type strain of the species. Seventeen lactobacilli clusters were defined, of which most were found both on rectal and oral mucosa. The largest taxa were Lactobacillus plantarum, Lact. rhamnosus and Lact. paracasei ssp. paracasei, which were isolated from 52%, 26% and 17% of the individuals, respectively. Most isolates were tested for their capacity to adhere to the human colonic cell line HT-29 in the absence and presence of methyl-alpha-D-mannoside. Mannose-sensitive adherence to HT-29 cells was encountered in two-thirds of the Lact. plantarum isolates, but infrequently among isolates of other taxa. The results suggest that Lact. plantarum is a major colonizer of the human gastrointestinal mucosa, and that its capacity to adhere to mannose-containing receptors may be of some ecological importance.
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| 8. |
- Vural, Gürcan, et al.
(författare)
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Inflammatory signs in wet smear and Pap-smear compared with the histopathology from the female lower genital tract.
- 1995
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Ingår i: Acta obstetricia et gynecologica Scandinavica. - : Wiley. - 0001-6349 .- 1600-0412. ; 74:6, s. 451-4
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Tidskriftsartikel (refereegranskat)abstract
- In order to define the relationship between various criteria of female lower genital tract inflammation, we examined wet smears, cervical smears and biopsies from 131 patients. The presence of clue cells in rehydrated dry smears showed a positive correlation to the presence of clue cells in Papanicolaou stained smears, and to some extent with cytological evidence of inflammation (Kappa 0.48). Cytological inflammatory findings correlated well with the presence of clue cells in rehydrated dry smears, but signs of inflammation diagnosed by histopathology did not correspond to findings in cytological smears, probably because these methods reveal inflammation at different sites.
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| 9. |
- Jensen, T, et al.
(författare)
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Cultured rat and purified human Pneumocystis carinii stimulate intra- but not extracellular free radical production in human neutrophils.
- 1998
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Ingår i: The Journal of eukaryotic microbiology. - 1066-5234. ; 45:5, s. 544-7
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Tidskriftsartikel (refereegranskat)abstract
- The production of free radicals in human neutrophils was studied in both Pneumocystis carinii derived from cultures of L2 rat lung epithelial-like cells and Pneumocystis carinii purified from human lung. Using the cytochrome C technique, which selectively measured extracellular superoxide generation, hardly any free radical production was observed after stimulation with cultured rat-derived P. carinii. A chemiluminescence technique, which separately measured intra- and extracellular free radical production, was subsequently employed to differentiate the free radical generation. It was established that 1) P. carinii stimulated intra- but not extracellular free radical production in human neutrophils, 2) opsonized cultured rat-derived P. carinii stimulated human neutrophils to a strong intracellular response of superoxide production, and 3) opsonized P. carinii, purified from human lung also stimulated human neutrophils to produce intracellular free radicals.
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| 10. |
- Mattsby-Baltzer, Inger, 1949, et al.
(författare)
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IL-1beta, IL-6, TNFalpha, fetal fibronectin, and endotoxin in the lower genital tract of pregnant women with bacterial vaginosis.
- 1998
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Ingår i: Acta obstetricia et gynecologica Scandinavica. - : Wiley. - 0001-6349. ; 77:7, s. 701-6
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Tidskriftsartikel (refereegranskat)abstract
- In our studies on women with bacterial vaginosis (BV) in early pregnancy a strong association has been found between BV and the levels of endotoxin or interleukin-1alpha (IL-1alpha) in the lower genital tract. In the present study we investigated if an association could be found between BV and other cytokines (IL-1beta, IL-6, tumor necrosis factor alpha, TNF) or fetal fibronectin (FFN). The cytokine-inducing capacity of endotoxins present in the cervical mucus was explored in a monocytic cell assay.Cervical mucus or cervicovaginal fluid was collected from women with (BV) and without BV (nonBV) attending a family planning unit for first trimester abortion. The concentrations of IL-1beta, IL-6, TNF and FFN were determined by quantitative enzyme immunoassays. TNF was determined in 63 women (BV, n=25) out of whom 37 (BV, n=11) were analyzed for IL-1beta and the remaining 26 for IL-6 (BV, n=14). FFN was determined in another 36 women (BV, n= 19). The cytokine-inducing capacity of endotoxin-containing cervical mucus and purified endotoxin of Prevotella bivia were studied by an in vitro cell assay using a human monocytic cell line (THP-1).IL-lbeta and IL-6 were found in almost all women. The levels of IL-1beta, but not IL-6, TNF or FFN, were significantly increased in women with BV compared with the nonBV women (p<0.05). Purified endotoxin from P. bivia, and cervical mucus from BV women containing high levels of endotoxin were able to induce a cytokine response (IL-6) in monocytic cells in vitro.BV is associated with increased levels of IL-1beta in the lower genital tract of pregnant women in the first trimester. The ability of BV-associated endotoxins to induce cytokine production in monocytic cells may partly explain the increased IL-1beta levels.
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