umu.sePublikasjoner
Endre søk
Begrens søket
12 1 - 50 of 80
RefereraExporteraLink til resultatlisten
Permanent link
Referera
Referensformat
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annet format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annet språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf
Treff pr side
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sortering
  • Standard (Relevans)
  • Forfatter A-Ø
  • Forfatter Ø-A
  • Tittel A-Ø
  • Tittel Ø-A
  • Type publikasjon A-Ø
  • Type publikasjon Ø-A
  • Eldste først
  • Nyeste først
  • Skapad (Eldste først)
  • Skapad (Nyeste først)
  • Senast uppdaterad (Eldste først)
  • Senast uppdaterad (Nyeste først)
  • Standard (Relevans)
  • Forfatter A-Ø
  • Forfatter Ø-A
  • Tittel A-Ø
  • Tittel Ø-A
  • Type publikasjon A-Ø
  • Type publikasjon Ø-A
  • Eldste først
  • Nyeste først
  • Skapad (Eldste først)
  • Skapad (Nyeste først)
  • Senast uppdaterad (Eldste først)
  • Senast uppdaterad (Nyeste først)
Merk
Maxantalet träffar du kan exportera från sökgränssnittet är 250. Vid större uttag använd dig av utsökningar.
  • 1.
    Aberg, Carola Höglund
    et al.
    Umeå universitet, Medicinsk fakultet, Odontologi. Umeå universitet, Medicinsk fakultet, Odontologi, Parodontologi.
    Sjödin, Bengt
    Lakio, Laura
    Pussinen, Pirkko J
    Johansson, Anders
    Umeå universitet, Medicinsk fakultet, Odontologi. Umeå universitet, Medicinsk fakultet, Odontologi, Parodontologi.
    Claesson, Rolf
    Umeå universitet, Medicinsk fakultet, Odontologi. Umeå universitet, Medicinsk fakultet, Odontologi, Oral mikrobiologi.
    Presence of Aggregatibacter actinomycetemcomitans in young individuals: a 16-year clinical and microbiological follow-up study.2009Inngår i: Journal of clinical periodontology, ISSN 1600-051X, Vol. 36, nr 10, 815-22 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    AIM: To look for clinical signs of periodontal disease in young adults who exhibited radiographic bone loss and detectable numbers of Aggregatibacter actinomycetemcomitans in their primary dentition. MATERIAL AND METHODS: Periodontal status and radiographic bone loss were examined in each of the subjects 16 years after the baseline observations. Techniques for anaerobic and selective culture, and checkerboard, were used to detect periodontitis-associated bacterial species. The isolated A. actinomycetemcomitans strains were characterized by polymerase chain reaction. RESULTS: Signs of localized attachment loss were found in three out of the 13 examined subjects. A. actinomycetemcomitans was recovered from six of these subjects and two of these samples were from sites with deepened probing depths and attachment loss. Among the isolated A. actinomycetemcomitans strains, serotypes a-c and e, but not d or f, were found. None of the isolated strains belonged to the highly leucotoxic JP2 clone, and one strain lacked genes for the cytolethal distending toxin. CONCLUSIONS: This study indicates that the presence of A. actinomycetemcomitans and early bone loss in the primary dentition does not necessarily predispose the individual to periodontal attachment loss in the permanent dentition.

  • 2. Al-Otaibi, M
    et al.
    Al-Harthy, M
    Gustafsson, A
    Johansson, Anders
    Umeå universitet, Medicinsk fakultet, Odontologi, Parodontologi.
    Claesson, Rolf
    Umeå universitet, Medicinsk fakultet, Odontologi, Oral mikrobiologi.
    Angmar-Månsson, B
    Subgingival plaque microbiota in Saudi Arabians after use of miswak chewing stick and toothbrush2004Inngår i: Journal of Clinical Periodontology, ISSN 0303-6979, Vol. 31, nr 12, 1048-53 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    BACKGROUND: The chewing stick, the miswak, is used in many developing countries as the traditional means for oral hygiene. It is prepared from the roots, twigs and stem of Salvadora persica or other alternative local plants. OBJECTIVES: To compare the effects of the chewing stick miswak (from S. persica) and toothbrush on subgingival plaque microflora among Saudi Arabian individuals. Further, to investigate whether components extracted from S. persica may interfere with the subgingival plaque micro-organisms. MATERIAL AND METHODS: Fifteen healthy Saudi Arabian male volunteers aged 21-36 years were included in a single-blind, randomized cross-over study. The participants were taught how to use each device properly. Plaque sampling for DNA test was performed at the baseline, 1 week after professional tooth cleaning, and after 3 weeks of either miswak or toothbrush use. Identification and quantification of microbial species were performed by the checkerboard method, using whole genomic, digoxigenin-labelled DNA probes. Inhibition zones around miswak were examined on agar plates with Actinobacillus actinomycetemcomitans and the leukotoxicity of this bacterium was analyzed in a bioassay with macrophages+/-extracts of miswak. RESULTS: Miswak and toothbrushing had a similar influence on the levels of the subgingival microbiota. However, A. actinomycetemcomitans was significantly more reduced by miswak (p<0.05) than by toothbrushing. These results were supported by our in vitro results which, indicated that extracts from S. persica might interfere with the growth and leukotoxicity of A. actinomycetemcomitans. CONCLUSIONS: In contrast to toothbrush use, miswak use significantly reduced the amount of A. actinomycetemcomitans in the subgingival plaque.

  • 3.
    Asikainen, Sirkka
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Oral mikrobiologi.
    Doğan, Başak
    Department of Periodontology, Faculty of Dentistry, Marmara University, Istanbul, Turkey.
    Turgut, Zeynep
    Department of Periodontology, Gazi University, Ankara, Turkey.
    Paster, Bruce J
    Department of Molecular Genetics, The Forsyth Institute, Boston, Massachusetts, United States of America.
    Bodur, Aysen
    Department of Periodontology, Gazi University, Ankara, Turkey.
    Oscarsson, Jan
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Oral mikrobiologi.
    Specified species in gingival crevicular fluid predict bacterial diversity2010Inngår i: PloS one, ISSN 1932-6203, Vol. 5, nr 10, e13589- s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Among a variety of detected species those traditionally classified as Gram-negative anaerobes growing in mature subgingival biofilms were the main predictors for species diversity in GCF samples as well as responsible for distinguishing GCF samples from PP samples. GCF bacteria may provide new prospects for studying dynamic properties of subgingival biofilms.

  • 4.
    Asikainen, Sirkka E
    Umeå universitet, Medicinsk fakultet, Odontologi, Oral mikrobiologi.
    Periodontal bacteria and cardiovascular problems.2009Inngår i: Future microbiology, ISSN 1746-0921, Vol. 4, 495-498 s.Artikkel i tidsskrift (Annet vitenskapelig)
  • 5.
    Aspholm, Marina
    Umeå universitet, Medicinsk fakultet, Odontologi, Oral mikrobiologi.
    Adaptation of Helicobacter pylori Adherence Properties in Promotion of Host Tropism and Inflammatory Disease2004Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Being among the most prevalent of persistent infectious agents in humans worldwide, Helicobacter pylori induces chronic inflammation (gastritis), which may progress to peptic ulceration and stomach cancer. The ability to adhere to the gastric mucosa is considered to be both a colonization and virulence property of H. pylori. For adherence, H. pylori expresses surface-located attachment proteins (adhesins) that bind to specific receptors in the gastric mucosa. The best characterized H. pylori adhesin-receptor interaction is that between the blood group antigen binding adhesin (BabA) and the fucosylated blood group antigens, which are glycans highly expressed in the gastric mucosa.

    Our recent results have changed the view of the blood group antigen-specific binding mode of H. pylori. We have tested clinical isolates of H. pylori from human populations worldwide for their ability to bind to ABO blood group antigens. The results revealed that more than 95% of isolates from Sweden, Germany, Spain, Japan and Alaska that bind fucosylated blood group antigens, bind both the Lewis b antigen (Leb) (of blood group O) and the blood group A-related antigen A-Lewis b, i.e. they exhibit a generalist type of binding mode. In contrast, the majority of strains (62%) from South American Amerindians bound best to Leb, i.e. they exhibit a specialist blood group “O antigen” binding mode. This specialization in binding coincides with the unique predominance of blood group O in the South American Amerindian populations. Furthermore, we also showed that H. pylori could switch from specialist to generalist binding modes by chromosomal integration of foreign babA gene fragments.

    A mutant strain lacking the babA gene turned out to adhere to inflamed gastric epithelium, despite the fact that it did not bind Leb. We identified the receptor to which the mutant binds to as the sialyl-dimeric-Lewis x antigen (sdiLex) and found its expression to be associated with persistent H. pylori infection and chronic inflammation, both in humans and Rhesus monkeys. The cognate sialic acid binding adhesin (SabA) was identified by our ReTagging technique. Deletion of sabA caused loss of H. pylori binding to sialylated glycans, and screening of single colony isolates revealed a high frequency of spontaneous on⇒off phase variation in sLex binding.

    Using erythrocytes as a model for sialyl dependent cell adhesion, we could show that SabA is the sought-after H. pylori sialyl-dependent hemagglutinin. Swedish clinical H. pylori isolates were analyzed for sialyl-dependent hemagglutination (sia-HA), and the sia-HA titers were found to be highly correlated to the levels of sLex binding. Clinical isolates were shown to exhibit several distinct binding modes for sialylated glycans, which suggest that SabA exhibit polymorphism in binding. We also found that SabA binds to sialylated glycans on neutrophil surfaces by mechanisms involving “selectin mimicry”, and that SabA plays an important role in nonopsonic activation of neutrophils.

    In the human stomach, H. pylori is exposed to selective pressures such as immune and inflammatory responses, and this is reflected by changes in mucosal glycosylation patterns. The high mutation and recombination rates of H. pylori in combination with bio selection will continuously generate clones that are adapted to changes in individual gastric mucosa. Such adaptive selection contributes to the remarkable diversity in binding modes and to the extraordinary chronicity of H. pylori infections worldwide.

  • 6.
    Aspholm-Hurtig, Marina
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Oral mikrobiologi.
    Dailide, Giedrius
    Lahmann, Martina
    Kalia, Awdhesh
    Ilver, Dag
    Roche, Niamh
    Vikström, Susanne
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Oral mikrobiologi.
    Sjöström, Rolf
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Oral mikrobiologi. Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk kemi och biofysik.
    Lindén, Sara
    Bäckström, Anna
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Oral mikrobiologi.
    Lundberg, Carina
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Oral mikrobiologi.
    Arnqvist, Anna
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Oral mikrobiologi. Umeå universitet, Medicinska fakulteten, Molekylärbiologi (Teknat- och Medfak). Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk kemi och biofysik.
    Mahdavi, Jafar
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Oral mikrobiologi.
    Nilsson, Ulf J
    Velapatiño, Billie
    Gilman, Robert H
    Gerhard, Markus
    Alarcon, Teresa
    López-Brea, Manuel
    Nakazawa, Teruko
    Fox, James G
    Correa, Pelayo
    Dominguez-Bello, Maria Gloria
    Perez-Perez, Guillermo I
    Blaser, Martin J
    Normark, Staffan
    Carlstedt, Ingemar
    Oscarson, Stefan
    Teneberg, Susann
    Berg, Douglas E
    Borén, Thomas
    Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk kemi och biofysik. Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Oral mikrobiologi.
    Functional adaptation of BabA, the H. pylori ABO blood group antigen binding adhesin.2004Inngår i: Science, ISSN 0036-8075, Vol. 305, nr 5683, 519-522 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Adherence by Helicobacter pylori increases the risk of gastric disease. Here, we report that more than 95% of strains that bind fucosylated blood group antigen bind A, B, and O antigens (generalists), whereas 60% of adherent South American Amerindian strains bind blood group O antigens best (specialists). This specialization coincides with the unique predominance of blood group O in these Amerindians. Strains differed about 1500-fold in binding affinities, and diversifying selection was evident in babA sequences. We propose that cycles of selection for increased and decreased bacterial adherence contribute to babA diversity and that these cycles have led to gradual replacement of generalist binding by specialist binding in blood group O-dominant human populations.

  • 7.
    Belibasakis, Georgios
    et al.
    Umeå universitet, Medicinsk fakultet, Odontologi, Oral mikrobiologi.
    Johansson, Anders
    Umeå universitet, Medicinsk fakultet, Odontologi, Parodontologi.
    Wang, Ying
    Claesson, Rolf
    Umeå universitet, Medicinsk fakultet, Odontologi, Oral mikrobiologi.
    Chen, Casey
    Asikainen, Sirkka
    Umeå universitet, Medicinsk fakultet, Odontologi, Oral mikrobiologi.
    Kalfas, Sotos
    Inhibited proliferation of human periodontal ligament cells and gingival fibroblasts by Actinobacillus actinomycetemcomitans: involvement of the cytolethal distending toxin2002Inngår i: European Journal of Oral Sciences, ISSN 0909-8836, Vol. 110, nr 5, 366-373 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Actinobacillus actinomycetemcomitans can inhibit fibroblast proliferation. The objective of this study was to characterize the early proliferative responses of human periodontal ligament cells (PDLC) and gingival fibroblasts (GF) to A. actinomycetemcomitans components and to investigate the possible involvement of the cytolethal distending toxin (cdt) produced by this bacterium. The PDLC and GF were challenged with surface components of A. actinomycetemcomitans. Both DNA and protein synthesis as well as cell lysis or apoptosis were assayed for a 6-h period after addition of the bacterial extract. Unlike the controls, inhibition of DNA synthesis had already occurred in the challenged cells at the end of the initial 3- to 6-h period. No lysis or apoptosis was detected, and the total protein synthesis remained unaffected. The persistence of the effect on cell growth was confirmed after a 72-h period of challenge, during which the cells remained viable but exhibited an elongated and distended cell body. No significant differences were observed between PDLC and GF. When a cdt-knockout strain of A. actinomycetemcomitans was used almost no inhibitory effect on cell proliferation was observed. It was concluded that A. actinomycetemcomitans causes a non-lethal inhibition of proliferation in PDLC and GF as a result of an early arrest of DNA synthesis. Cytolethal distending toxin is responsible for most of this effect. This bacterial property may compromise tissue homeostasis in the periodontium.

  • 8.
    Belibasakis, Georgios N.
    Umeå universitet, Medicinsk fakultet, Odontologi, Oral mikrobiologi. Umeå universitet, Medicinsk fakultet, Odontologi, Oral cellbiologi.
    Cellular and molecular responses of periodontal connective tissue cells to Actinobacillus actinomycetemcomitans cytolethal distending toxin2004Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Actinobacillus actinomycetemcomitans is present in elevated proportions and numbers in dental bacterial biofilms of patients with localized aggressive periodontitis. This variant of periodontal disease, occurring in adolescents and young adults, is characterized by rapid and severe destruction of the connective tissues and bone supporting the teeth, eventually culminating in tooth loss. The cytolethal distending toxin (Cdt) is a newly discovered bacterial protein toxin, uniquely present in A. actinomycetemcomitans among all known to-date oral bacterial species. The Cdt has the capacity to inhibit mammalian cell growth, but its putative role in the pathogenesis of the disease is unclear. The aim of this in vitro work has been to study the effects of A. actinomycetemcomitans on periodontal connective tissue cell cultures, and to evaluate the possible involvement of its Cdt.

    A. actinomycetemcomitans inhibited the proliferation of gingival and periodontal ligament fibroblasts, as a result of a combined arrest at the G1 and G2/M phases of the cell cycle. This growth inhibition was non-lethal and the cells remained metabolically active, although their DNA synthesis was reduced. The intoxicated cells exhibited increased size and irregular structure, characterized by distension and elongation. This cellular enlargement occurred in both G1 and G2/M phase arrested cells. The Cdt of A. actinomycetemcomitans was responsible for the observed growth inhibition, as well as the concomitant morphological alterations.

    The possible induction of inflammatory cytokines related to bone resorption was investigated in response to A. actinomycetemcomitans, and the involvement of Cdt was evaluated. Extensive focus was given to the study of receptor activator of NF-κB ligand (RANKL) expression, a membrane-bound ligand that signals osteoclast progenitors to differentiate and fuse into mature osteoclasts, activating bone resorption. It was demonstrated that A. actinomycetemcomitans induced RANKL mRNA and protein expression in the cells studied, but did not affect the expression of its decoy receptor, osteoprotegerin. This induction was solely attributed to its Cdt, as demonstrated by the use of a cdt-knockout A. actinomycetemcomitans strain, purified recombinant Cdt, and antibodies blocking the Cdt. In addition, this event was not mediated by pro-inflammatory cytokines known to stimulate RANKL. Interleukin-6 mRNA and protein expression were also enhanced by A. actinomycetemcomitans, but Cdt had limited involvement in this enhancement.

    In conclusion, two distinct mechanisms by which A. actinomycetemcomitans Cdt may be involved in the pathogenesis of localized aggressive periodontitis are proposed. Firstly, the growth arrest of the resident fibroblasts may impair the physiological connective tissue remodelling equilibrium and lead to connective tissue attachment loss. Secondly, the induction of RANKL by these cells, residing in the proximity of the alveolar bone, may locally stimulate osteoclastogenesis and promote alveolar bone resorption. This work also provides further insights to the understanding of Cdt mechanisms of action, contributing to the global characterization of the toxin’s virulence.

  • 9.
    Belibasakis, Georgios N
    et al.
    Umeå universitet, Medicinsk fakultet, Odontologi, Oral cellbiologi. Umeå universitet, Medicinsk fakultet, Odontologi, Oral mikrobiologi.
    Johansson, Anders
    Umeå universitet, Medicinsk fakultet, Odontologi, Parodontologi.
    Wang, Y
    Chen, C
    Kalfas, S
    Lerner, Ulf
    Umeå universitet, Medicinsk fakultet, Odontologi, Oral cellbiologi.
    The cytolethal distending toxin induces receptor activator of NF-κB ligand expression in human gingival fibroblasts and periodontal ligament cells2005Inngår i: Infection and Immunity, ISSN 0019-9567, Vol. 73, nr 1, 342-351 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Actinobacillus actinomycetemcomitans is associated with localized aggressive periodontitis, a disease characterized by rapid loss of the alveolar bone surrounding the teeth. Receptor activator of NF-kappaB Ligand (RANKL) and osteoprotegerin (OPG) are two molecules that regulate osteoclast formation and bone resorption. RANKL induces osteoclast differentiation and activation, whereas OPG blocks this process by acting as a decoy receptor for RANKL. The purpose of this study was to investigate the effect of A. actinomycetemcomitans on the expression of RANKL and OPG in human gingival fibroblasts and periodontal ligament cells. RANKL mRNA expression was induced in both cell types challenged by A. actinomycetemcomitans extract, whereas OPG mRNA expression remained unaffected. Cell surface RANKL protein was also induced by A. actinomycetemcomitans, whereas there was no change in OPG protein secretion. A cytolethal distending toxin (Cdt) gene-knockout strain of A. actinomycetemcomitans did not induce RANKL expression, in contrast to its wild-type strain. Purified Cdt from Haemophilus ducreyi alone, or in combination with extract from the A. actinomycetemcomitans cdt mutant strain, induced RANKL expression. Pretreatment of A. actinomycetemcomitans wild-type extract with Cdt antiserum abolished RANKL expression. In conclusion, A. actinomycetemcomitans induces RANKL expression in periodontal connective tissue cells. Cdt is crucial for this induction and may therefore be involved in the pathological bone resorption during the process of localized aggressive periodontitis.

  • 10.
    Belibasakis, Georgios N
    et al.
    Umeå universitet, Medicinsk fakultet, Odontologi, Oral mikrobiologi. Umeå universitet, Medicinsk fakultet, Odontologi, Oral cellbiologi.
    Johansson, Anders
    Umeå universitet, Medicinsk fakultet, Odontologi, Parodontologi.
    Wang, Y
    Chen, C
    Lagergård, T
    Kalfas, S
    Lerner, Ulf
    Umeå universitet, Medicinsk fakultet, Odontologi, Oral cellbiologi.
    Cytokine responses of human gingival fibroblasts to Actinobacillus actinomycetemcomitans cytolethal distending toxin2005Inngår i: Cytokine, ISSN 1043-4666, Vol. 30, nr 2, 56-63 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Actinobacillus actinomycetemcomitans is implicated in the pathogenesis of localized aggressive periodontitis, and has the capacity to express a cytolethal distending toxin (Cdt). Gingival fibroblasts (GF) are resident cells of the periodontium, which can express several osteolytic cytokines. The aims of this study were a) to investigate the role of Cdt in A. actinomycetemcomitans-induced expression of osteolytic cytokines and their cognate receptors in GF and b) to determine if the previously demonstrated induction of receptor activator of NFkappaB ligand (RANKL) by A. actinomycetemcomitans is mediated by these pro-inflammatory cytokines or by prostaglandin E(2) (PGE(2)). A. actinomycetemcomitans clearly induced interleukin (IL)-6, IL-1beta, and to a minimal extent, tumor necrosis factor (TNF)-alpha mRNA expression. At the protein level, IL-6 but not IL-1beta or TNF-alpha expression was stimulated. The mRNA expression of the different receptor subtypes recognizing IL-6, IL-1beta and TNF-alpha was not affected. A cdt-knockout strain of A. actinomycetemcomitans had similar effects on cytokine and cytokine receptor mRNA expression, compared to its parental wild-type strain. Purified Cdt stimulated IL-6, but not IL-1beta or TNF-alpha protein biosynthesis. Antibodies neutralizing IL-6, IL-1 or TNF-alpha, and the PGE(2) synthesis inhibitor indomethacin, did not affect A. actinomycetemcomitans-induced RANKL expression. In conclusion, a) A. actinomycetemcomitans induces IL-6 production in GF by a mechanism largely independent of its Cdt and b) A. actinomycetemcomitans-induced RANKL expression in GF occurs independently of IL-1, IL-6, TNF-alpha, or PGE(2).

  • 11.
    Belibasakis, Georgios N
    et al.
    Umeå universitet, Medicinsk fakultet, Odontologi, Oral cellbiologi. Umeå universitet, Medicinsk fakultet, Odontologi, Oral mikrobiologi.
    Mattsson, Anna
    Umeå universitet, Medicinsk fakultet, Odontologi, Parodontologi.
    Wang, Ying
    Chen, Casey
    Johansson, Anders
    Umeå universitet, Medicinsk fakultet, Odontologi, Parodontologi.
    Cell cycle arrest of human gingival fibroblasts and periodontal ligament cells by Actinobacillus actinomycetemcomitans: involvement of the cytolethal distending toxin2004Inngår i: Acta Pathologica, Microbiologica et Immunologica Scandinavica (APMIS), ISSN 0903-4641, Vol. 112, nr 10, 674-685 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The cytolethal distending toxin (Cdt) is produced by several Gram-negative bacterial species and causes growth arrest and morphological alterations in mammalian cells. Actinobacillus actinomycetemcomitans, which is involved in the pathogenesis of localized aggressive periodontitis, also produces a Cdt that affects periodontal connective tissue cells. The aim of this study was to investigate in which phase of the cell cycle these cells are arrested and enlarged when challenged with A. actinomycetemcomitans, and to evaluate the involvement of its Cdt. Human gingival fibroblasts and periodontal ligament cells were challenged with A. actinomycetemcomitans extract, or with purified Cdt, and cell cycle analysis was performed by propidium iodide staining and flow cytometry. Cells exposed to an A. actinomycetemcomitans wild-type strain, or to purified Cdt, were arrested in both G1 and G2/M phases, and appeared enlarged compared to the corresponding controls. The cellular enlargement occurred in both G1 and G2/M arrested cells. In contrast, cells exposed to an A. actinomycetemcomitans cdt-knockout mutant strain showed cell cycle phase distribution and size similar to the controls. In conclusion, A. actinomycetemcomitans causes a combined G1 and G2/M growth arrest and enlargement in periodontal connective tissue cells, which is attributed to its Cdt.

  • 12. Brazier, J
    et al.
    Chmelar, D
    Dubreuil, L
    Feierl, G
    Hedberg, Maria
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Oral mikrobiologi.
    Kalenic, S
    Könönen, E
    Lundgren, B
    Malamou-Ladas, H
    Nagy, E
    Sullivan, Å
    Nord, CE
    European surveillance study on antimicrobial susceptibility of Gram-positive anaerobic cocci2008Inngår i: International Journal of Antimicrobial Agents, ISSN 0924-8579, E-ISSN 1872-7913, Vol. 31, nr 4, 316-320 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Gram-positive anaerobic cocci (GPAC) are a heterogeneous group of microorganisms frequently isolated from local and systemic infections. In this study, the antimicrobial susceptibilities of clinical strains isolated in 10 European countries were investigated. After identification of 299 GPAC to species level, the minimum inhibitory concentrations of penicillin, imipenem, clindamycin, metronidazole, vancomycin and linezolid were determined by the agar dilution method according to the Clinical and Laboratory Standards Institute. The majority of isolates were identified as Finegoldia magna and Parvimonas micra (formerly Peptostreptococcus micros), isolated from skin and soft tissue infections. All isolates were susceptible to imipenem, metronidazole, vancomycin and linezolid. Twenty-one isolates (7%) were resistant to penicillin (n=13) and/or to clindamycin (n=12). Four isolates were resistant to both agents. The majority of resistant isolates were identified as F. magna and originated from blood, abscesses and soft tissue infections.

  • 13.
    Byström, Anders
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Endodonti. Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Oral mikrobiologi.
    Evaluation of endodontic treatment of teeth with apical periodontitis1986Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Apical periodontitis, an acute or chronic inflamination around the apex of the tooth, is caused by bacteria in the root canal. In Sweden the dentists devote around 10X of their total time to treating this disease. The treatment usually requires 3 to 5 sessions. The treatment may fail in up to 25X of the cases. In the present study various treatment regimens were evaluated. One hundred and forty singlerooted teeth with apical periodontitis were treated. The importance of mechanical instrumentation, irrigating solutions and antibacterial dressings in eliminating bacteria from the infected root canals was studied using bacteriological techniques. The healing of the apical periodontitis after treatment was followed for 2 to 5 years on recall radiographs.

    Bacteria were found in all 140 root canals at the beginning of the treatment. Most of these bacteria were anaerobes and they represented a restricted group of bacteria compared to the bacteria present at other sites in the oral cavity. Mechanical instrumentation with files and reamers in combination with saline irrigation reduced the number of bacterial cells in the root canal 100- to 1000-fold during one treatment session. Bacteria could be eliminated from about half the number of root canals if this treatment was performed at 4 sessions.

    Mechanical instrumentation and irrigation with 0.5X or 5X sodium hypochlorite solutions or with the 5X solution in combination with 15X EDTA solution wa3 more efficient and the bacteria were eliminated from about half the treated canals after one treatment session. The bacteria which persisted in the root canal after this treatment usually increased in number during the interval up to the next session and reached levels which were often as high as in the initial sample at the previous session.

    All bacteria persistent in the root canals after the previous treatment regimens were with 2 exceptions eliminated by dressing the root canals for 1 to 2 months with calcium hydroxide paste. Thirty-four out of 35 root canals treated at the first session with mechanical instrumentation, irrigation with sodium hypochlorite solution and dressed with calcium hydroxide paste were free of bacteria at the second session. Calcium hydroxide paste was superior to camphorated phenol and camphorated paramonochlorophenol as dressing.

    Healing of 79 out of the 140 treated teeth was followed for 2 to 5 years. The majority of the lesions healed completely or decreased in size in such a way that they could be expected to heal. There was no or only an insignificant decrease in the size of the lesions in 5 cases. In 2 of these cases bacteria were demonstrated in the periapical tissues and in a third case dentin chips. Periapical lesions may thus fail to heal in a few cases due to an establishment of bacteria outside the root canal, and in that site the bacteria are inaccessible to conventional endodontic treatment.

    The present study showed that treatment of the majority of infected non-vital teeth can be completed in only 2 sessions, if mechanical instrumentation, sodium hypochlorite irrigation and calcium hydroxide dressing are combined.

  • 14.
    Crossner, Claes-Göran
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Oral mikrobiologi.
    Försök till tidig diagnos av kariessjukdomen1980Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    The aim of the present thesis was to find a test for prediction of caries activity which would be useful in routine clinical work.Correlations between oral health, general health, food habits and socioeconomic conditions were investigated in 4- and 8-year-old children. It was found that the salivary secretion rate and the prevalence of oral lactobacilli were factors which might be useful in caries prediction.In 5- and 8-year-old children negative correlations between caries frequency and secretion rate, pH and buffer effect of saliva were demonstrated. However, these parameters showed a wide range of variation.A dip-slide test (Dentocult®), for determination of the number of lactobacilli in saliva, were investigated. The test proved to be reliable for determining of the number of lactobacilli in saliva.The clinical use of information on salivary secretion rate and number of lactobacilli in saliva in prediction of caries activity was examined in 115 14-year-old children over a period of 64 weeks. The number of lactobacilli in saliva, but not the salivary secretion rate, was correlated to caries activity. The number of lactobacilli in saliva seems to reflect the frequency of ingested fermentable carbohydrates and indirectly the risk for initiation of carious lesions. However, when the lactobacillus test is used it is important that there are no such areas of microbial retention on the teeth, as open cavities, poorly executed conservations, dentures or orthodontic bands. The lactobacillus test would make it possible to individualize prophylactic caries treatment.

  • 15. Dogan, B
    et al.
    Antinheimo, J
    Cetiner, D
    Bodur, A
    Emingil, G
    Buduneli, E
    Uygur, C
    Firatli, E
    Lakio, L
    Asikainen, Sirkka
    Umeå universitet, Medicinsk fakultet, Odontologi, Oral mikrobiologi.
    Subgingival microflora in Turkish patients with periodontitis.2003Inngår i: Journal of Periodontology, ISSN 0022-3492, Vol. 74, nr 6, 803-814 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    BACKGROUND: No information exists on periodontitis-associated subgingival microbiota from Turkey. We determined the occurrence, interspecies relationships, and clonal characteristics for a group of periodontal bacteria in a Turkish study population. METHODS: Subgingival microbial samples were obtained from patients with localized (LAgP, N = 18) or generalized (GAgP, N = 17) types of aggressive periodontitis, generalized chronic periodontitis (GCP, N = 14), and non-periodontitis subjects (N = 20). Culture methods were used to recover 6 periodontal bacterial species and yeasts, and a polymerase chain reaction technique was used to detect Actinobacillus actinomycetemcomitans and Porphyromonas gingivalis. Intraspecies characterization of A. actinomycetemcomitans was carried out by serotyping and genotyping. RESULTS: All species, except for Micromonas micros (formerly Peptostreptococcus micros) occurred more frequently (P < 0.05) in periodontitis than non-periodontitis subjects. Detection frequencies for Tannerella forsythensis (formerly Bacteroides forsythus) and Campylobacter rectus differed among the periodontitis subgroups; the lowest frequency occurred in LAgP. The mean proportions of A. actinomycetemcomitans, P. gingivalis, and C. rectus were higher (P < 0.008) in GAgP than in non-periodontitis subjects. Significant positive associations were seen between 7 of the 22 possible combinations (P < 0.05). A. actinomycetemcomitans serotype c (34%) and non-serotypeable isolates (34%) were the most common antigenic types among the 305 strains analyzed. Eleven arbitrarily primed (AP)-PCR genotypes were distinguished among 273 isolates from 29 subjects. Yeasts were found in 23% of the 69 subjects. CONCLUSIONS: The results on the Turkish study population were generally in line with earlier reports on the occurrence and interspecies relationships of certain bacteria in periodontitis. However, A. actinomycetemcomitans was not overrepresented in LAgP, and the serotype distribution resembled that reported from the East. The high frequency of non-serotypeable isolates suggests local characteristics of the species.

  • 16. Dogan, B
    et al.
    Buduneli, E
    Emingil, G
    Atilla, G
    Akilli, A
    Antinheimo, J
    Lakio, L
    Asikainen, Sirkka
    Umeå universitet, Medicinsk fakultet, Odontologi, Oral mikrobiologi.
    Characteristics of periodontal microflora in acute myocardial infarction.2005Inngår i: Journal of Periodontology, ISSN 0022-3492, Vol. 76, nr 5, 740-748 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    BACKGROUND: Periodontitis has been linked to increased risk of cardiovascular diseases. Systemic reactions associated with cardiovascular events may depend on characteristics of the subgingival microflora in periodontitis. Our objectives were to compare the numbers of cultivable bacteria, composition of subgingival microflora and clonal distribution of Actinobacillus actinomycetemcomitans (A. actinomycetemcomitans) in two groups of patients with generalized chronic periodontitis (GCP), one with an acute myocardial infarction (AMI-GCP) and the other one without AMI (non-AMI-GCP). METHODS: In all, 150 dentate individuals were screened for suitability to this study. Subgingival bacterial samples were collected from 11 AMI-GCP and 11 non-AMI-GCP patients who had been selected using strict inclusion criteria in an attempt to exclude confounding factors and to increase comparability of periodontal conditions by matching for periodontal probing depths and attachment levels. Culture methods were used to determine the total viable counts and occurrence and proportions of six periodontal bacterial species and yeasts. Polymerase chain reaction (PCR) technique was used to detect A. actinomycetemcomitans and Porphyromonas gingivalis (P. gingivalis). Intraspecies characterization of A. actinomycetemcomitans included serotyping and genotyping. RESULTS: The mean proportions of P. gingivalis (P = 0.05) and Tannerella forsythensis (T. forsythensis) (P = 0.01) were significantly lower, but the numbers of Micromonas micros (M. micros) and A. actinomycetemcomitans were up to nine times higher and the mean total number of cultivable bacteria per sample higher (P <0.01) in AMI-GCP than in non-AMI-GCP. CONCLUSION: The findings that no target subgingival species were overrepresented but the total bacterial number was higher in AMI-GCP than non-AMI-GCP patients may provide support to the hypothesis that elevated numbers of bacteria in close vicinity to sterile parenteral area present a risk for systemic health.

  • 17.
    Ekici, Rifat
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för klinisk mikrobiologi, Immunologi/immunkemi.
    Sundström, Mia
    Umeå universitet, Medicinska fakulteten, Institutionen för klinisk mikrobiologi, Immunologi/immunkemi.
    Thay, Bernard
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Oral mikrobiologi.
    Lejon, Kristina
    Umeå universitet, Medicinska fakulteten, Institutionen för klinisk mikrobiologi, Immunologi/immunkemi. Umeå universitet, Medicinska fakulteten, Institutionen för klinisk mikrobiologi, Biomedicinsk laboratorievetenskap.
    Enhanced capture of extramembranous IgM and IgG on B cells in the NOD mouse: implications for immune complex trapping2009Inngår i: International Immunology, ISSN 0953-8178, E-ISSN 1460-2377, Vol. 21, nr 5, 533-541 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Binding of various antibody isotypes to B cells through either FcgammaRs or complement receptors has been attributed to play several roles, e.g. in immune complex (IC) transportation and regulation of B cell receptor signaling. We have revealed a novel B cell intrinsic receptor for IgM and IgG which is present in C57BL/6 (B6) mice and is more abundant in non-obese diabetic (NOD) mice. As a consequence, the level of extramembranous IgG monomers and IgM pentamers on peripheral blood B cells from NOD mice was significantly higher compared with B6 mice. The effect of this aberration was that all B cells in peripheral blood of (NOD.IgH(a) x B6(IgH(b)))F(1) mice carried both IgM allotypes on their surface. In addition, analysis of IC binding using IgG- or IgM-opsonized bacterial particles revealed a higher degree of binding in NOD mice compared with B6. We hypothesize that this novel Ig-binding receptor is part of the normal immune system function. The aberrant function in the NOD mouse could contribute to the development of Type 1 diabetes by altering normal B cell functions such as activation, IC transportation and B cell homeostasis.

  • 18. Fujise, O
    et al.
    Lakio, L
    Wang, Y
    Asikainen, Sirkka
    Umeå universitet, Medicinsk fakultet, Odontologi, Oral mikrobiologi.
    Chen, C
    Clonal distribution of natural competence in Actinobacillus actinomycetemcomitans.2004Inngår i: Oral Microbiology and Immunology, ISSN 0902-0055, Vol. 19, nr 5, 340-342 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The competence for natural transformation was investigated in 67 Actinobacillus actinomycetemcomitans strains. The transformation assays were performed with both cloned DNA fragments and chromosomal markers of A. actinomycetemcomitans. Competence was found in 12 of 18 serotype a strains, 0 of 21 serotype b strains, 0 of 14 serotype c strains, 3 of 6 serotype d strains, 3 of 4 serotype e strains, 0 of 3 serotype f strains, and 0 of 1 nonserotypeable strain. The transformation frequencies varied from 5 x 10(-3) to 4 x 10(-6) (median 1.5 x 10(-4)). The distribution pattern of natural competence is concordant with the major clonal lineages of A. actinomycetemcomitans. Serotype a strains are predominantly competent for transformation, while serotypes b and c strains are apparently non-competent.

  • 19. Gustafsson, Erik
    et al.
    Karlsson, Stefan
    Oscarsson, Jan
    Umeå universitet, Medicinsk fakultet, Odontologi. Umeå universitet, Medicinsk fakultet, Odontologi, Oral mikrobiologi.
    Sögård, Peter
    Nilsson, Patric
    Arvidson, Staffan
    Mathematical modelling of the regulation of spa (protein A) transcription in Staphylococcus aureus.2009Inngår i: International journal of medical microbiology : IJMM, ISSN 1618-0607, Vol. 299, nr 1, 65-74 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]
    In the present work a general systems biology approach has been used to study the complex regulatory network controlling the transcription of the spa gene, encoding protein A, a major surface protein and an important virulence factor of Staphylococcus aureus. A valid mathematical model could be formulated using parameter values, which were fitted to quantitative Northern blot data from various S. aureus regulatory mutants using a gradient search method. The model could correctly predict spa expression levels in 4 different regulatory mutants not included in the parameter value search, and in 2 other S. aureus strains, SH1000 and UAMS-1. The mathematical model revealed that sarA and sarS seem to balance each other in a way that when the activating impact of sarS is small, e.g. in the wild-type, the repressive impact of sarA is small, while in an agr-deficient background, when the impact of sarS is maximal, the repressive impact of sarA is close to its maximum. Furthermore, the model revealed that Rot and SarS act synergistically to stimulate spa expression, something that was not obvious from experimental data. We believe that this mathematical model can be used to evaluate the significance of other putative interactions in the regulatory network governing spa transcription.
  • 20. Gustafsson, Erik
    et al.
    Oscarsson, Jan
    Umeå universitet, Medicinsk fakultet, Odontologi. Umeå universitet, Medicinsk fakultet, Odontologi, Oral mikrobiologi.
    Maximal transcription of aur (aureolysin) and sspA (serine protease) in Staphylococcus aureus requires staphylococcal accessory regulator R (sarR) activity.2008Inngår i: FEMS Microbiology Letters, ISSN 0378-1097, Vol. 284, nr 2, 158-64 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Previous studies have shown that expression of aur (metalloprotease; aureolysin) and sspA (V8 protease; serine protease) in Staphylococcus aureus strain 8325-4 is maximal in the postexponential phase of growth, when the agr (RNAIII) system is activated. Transcription of aur and sspA is mainly regulated through repression by sarA and rot, and RNAIII stimulates protease production by inhibiting translation of rot mRNA. As SarR is a repressor of sarA, inactivation of sarR would result in downregulation of aur and sspA transcription. This was confirmed by mRNA analysis using quantitative real-time PCR. However, we found that sarR acted as a direct stimulator, i.e. its positive effect on aur and sspA transcription did not require sarA (or rot) per se. In addition, aur and sspA were dependent on sarR for maximal transcription. This stimulating role of sarR was not restricted to the rsbU-deficient laboratory strain 8325-4 but was also demonstrated in S. aureus strain SH1000 (rsbU-complemented derivative of 8325-4) and in one clinical isolate.

  • 21.
    Hasslöf, Pamela
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Pedodonti.
    Hedberg, Maria
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Oral mikrobiologi.
    Twetman, Svante
    Stecksén-Blicks, Christina
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Pedodonti.
    Growth inhibition of oral mutans streptococci and candida by commercial probiotic lactobacilli: an in vitro study2010Inngår i: BMC Oral Health, ISSN 1472-6831, Vol. 10, 18- s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The selected probiotic strains showed a significant but somewhat varying ability to inhibit growth of oral mutans streptococci and Candida albicans in vitro.

  • 22.
    Hedberg, Maria
    et al.
    Umeå universitet, Medicinsk fakultet, Odontologi, Oral mikrobiologi.
    Asikainen, Sirkka
    Umeå universitet, Medicinsk fakultet, Odontologi, Oral mikrobiologi.
    Growth inhibition of Porphyromonas gingivalis biofilm by lactobacilli2007Rapport (Annet vitenskapelig)
    Abstract [en]

    Background. Chronic periodontitis is one of the most common infectious diseases of the oral cavity. Dental plaque contains a mix of oral bacteria, and grows as biofilm on tooth surfaces. One of the bacterial species associated with periodontitis is Porphyromonas gingivalis, a Gram-negative anaerobic rod. Lactobacilli are used in probiotic products and are known to play an important role in the management of health by stimulating the immune system and contributing to the balance of the normal microflora. The knowledge of probiotic effects on oral bacteria is at present limited.

    Purpose. Lactobacillus reuteri, and Lactobacillus acidophilus are two species used in different probiotic products. In the presence of glycerol L. reuteri produces an antimicrobial product, 3-hydroxypropionaldehyd, also called reuterin. The purpose of the study was to examine the impact of L. reuteri and L. acidophilus on biofilm formed by P. gingivalis.

    Methods. To study whether L. reuteri and L. acidophilus had ability to alter the biofilm formation of P. gingivalis, 108 CFU/mL P. gingivalis and 108 CFU/mL of one of the lactobacilli were co-cultured in Brucella broth using cell-culture plates. After 48 h incubation the broth was removed and the biofilm studied by microscopy, crystal violet staining with subsequent absorbance measurements at 590 nm. Viable bacterial cells were determined in the biofilm and in the removed growth medium.

    Results. P. gingivalis and L. reuteri cultured individually formed heavy layers of biofilm (A590=2.1-3.1), whereas L. acidophilus gave a very thin layer (A590=0.21-0.35). In the biofilm competition assay, the level of viable P. gingivalis cells were reduced by at least 3 logs regardless the addition of glycerol when co-cultured with L. reuteri or L. acidophilus. In presence of glycerol, both P. gingivalis and L. reuteri were reduced below the detection level after 48 h incubation.

    Even though P. gingivalis cultured as single species formed a dense biofilm this was strongly reduced when co-cultured with L. acidophilus.

    Conclusion. In summary, the observed glycerol-dependent growth inhibition of P. gingivalis by L. reuteri seemed to be due to reuterin production. Competition in the biofilm model appeared to favor both lactobacillus species tested at the expense of P. gingivalis. The lactobacilli were able to strongly inhibit or suppress the growth of a major periodontal pathogen in the biofilm-competition assay.

  • 23.
    Hedberg, Maria
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Oral mikrobiologi.
    Hasslöf, Pamela
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Pedodonti.
    Sjöström, I
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Pedodonti.
    Twetman, S
    Stecksén-Blicks, Christina
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Pedodonti.
    Sugar fermentation in probiotic bacteria: an in vitro study2008Inngår i: Oral Microbiology and Immunology, ISSN 0902-0055, E-ISSN 1399-302X, Vol. 23, nr 6, 482-485 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    INTRODUCTION: Food supplemented with probiotic bacteria is a rapidly growing sector of the market. The aim of the present study was to evaluate and compare the acid production of selected probiotic strains available in commercial products.

    METHODS: Six Lactobacillus strains (Lactobacillus plantarum 299v and 931; Lactobacillus rhamnosus GG and LB21; Lactobacillus paracasei subsp. paracasei F19, and Lactobacillus reuteri PTA 5289) were cultivated at 37 degrees C in an anaerobic atmosphere on Man, Rogosa, Shape (MRS) agar for 48 h or MRS broth for 16 h. After centrifugation, the cells were washed and resuspended in sterile phosphate-buffered saline and immediately subjected to a fermentation assay with 12 different carbohydrates (nine sugars and three sugar alcohols) in microtiter plates with a pH indicator. The plates were examined for color changes after 24, 48, and 72 h of incubation under aerobic and anaerobic conditions. Three scores were used: negative (pH > 6.8); weak (pH 5.2-6.8), and positive (pH < 5.2). The strains were characterized with the API 50 CH system to confirm their identity.

    RESULTS: L. plantarum fermented all the sugars except for melibiose, raffinose, and xylitol. Both L. rhamnosus strains were generally less active although L. rhamnosus GG was slightly more active than strain LB21 in the 5% CO(2) setting. The latter strain exhibited negative reactions for sucrose, maltose, arabinose, and sorbitol under anaerobic conditions. The assays with L. paracasei and L. reuteri had negative or weak reactions for all tested sugars under both aerobic and anaerobic conditions.

    CONCLUSION: The metabolic capacity to form acid from dietary sugars differed significantly between the various probiotic strains.

  • 24.
    Hedberg, Maria
    et al.
    Umeå universitet, Medicinsk fakultet, Odontologi, Oral mikrobiologi.
    Hasslöf, Pamela
    Umeå universitet, Medicinsk fakultet, Odontologi, Pedodonti.
    Sjöström, Inger
    Umeå universitet, Medicinsk fakultet, Odontologi, Pedodonti.
    Stecksén-Blicks, Christina
    Umeå universitet, Medicinsk fakultet, Odontologi, Pedodonti.
    Twetman, Svante
    University of Copenhagen.
    In vitro inhibition of mutans streptococci by probiotic lactobacilli2009Rapport (Annet vitenskapelig)
  • 25.
    Hedberg, Maria
    et al.
    Umeå universitet, Medicinsk fakultet, Odontologi, Oral mikrobiologi.
    Karched, Maribasappa
    Asikainen, Sirkka
    Umeå universitet, Medicinsk fakultet, Odontologi, Oral mikrobiologi.
    In-vitro growth inhibition of periodontitis-associated species by Lactobacillus reuteri2006Rapport (Annet vitenskapelig)
    Abstract [en]

    Purpose. Lactobacillus reuteri, a species used in probiotic products, produces in vitro a bacteriocin, reuterin, in the presence of glycerol. The purpose of the study was to investigate in vitro whether L. reuteri strains inhibit the growth of periodontal pathogens.

    Methods. The inhibition study was based on a disk-diffusion method. The periodontitis-associated bacteria were pre-grown for 20 h in Brucella broth or Brucella blood agar at 37oC in anaerobic atmosphere. Standardization of bacterial inocula used in the assay was made by determinations of optical density, microscopic counting of cells, and viable count. Brucella blood agar plates, without or with glycerol (100 mM), were seeded with standardized inocula of the periodontal pathogens Fusobacterium nucleatum (IDH 4186), Porphyromonas gingivalis (ATCC 33277), Prevotella intermedia (ATCC 25611), and Actinobacillus actinomycetemcomitans (SA 1398). The lactobacilli L. reuteri ATCC 55730 and L. reuteri PTA 5289 were grown for 16 h in MRS broth. A 20-L aliquot of the suspension containing 107 CFU/mL was used to soak 6-mm paper disks, which were placed on Brucella agar plates (diameter 14 cm), seeded with each periodontal pathogen separately. The plates were then incubated for 3 - 7 days in anaerobic atmosphere at 37oC before measuring the inhibition zones.

    Results. On Brucella blood agar plates seeded with periodontal pathogens, no inhibition zones were seen around the paper discs. When glycerol was added to the agar, zones of 26 to 118 mm appeared. Sizes of the zones depended on the L. reuteri strain, the periodontal pathogen, and the sizes of their inocula. L. reuteri PTA 5289 had a stronger (7-30%) inhibitory effect than L. reuteri ATCC 55730 on all periodontal species. P. gingivalis was the most susceptible species among the tested strains.

    Conclusion. Both L. reuteri strains strongly inhibited or suppressed the growth of the tested periodontitis-associated bacteria in the presence of glycerol. The inhibitory activity of L. reuteri PTA 5289 was consistently higher than that of L. reuteri ATCC 55730. The results suggest that the inhibition activity of the tested lactobacilli was related to reuterin.

  • 26.
    Hedberg, Maria
    et al.
    Umeå universitet, Medicinsk fakultet, Odontologi, Oral mikrobiologi.
    Nord, Carl Erik
    Karoloinska Institute,.
    Anaerobic bacteria2008Inngår i: Antimicrobial therapy and vaccines: volume I: Microbes, New York: Apple Trees Production, LLC , 2008, 3rdKapittel i bok, del av antologi (Annet vitenskapelig)
  • 27.
    Höglund Åberg, Carola
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Molekylär paradontologi.
    Kwamin, Francis
    Univ Ghana, Sch Dent, Accra, Ghana.
    Claesson, Rolf
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Oral mikrobiologi.
    Johansson, Anders
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Molekylär paradontologi. Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Oral mikrobiologi.
    Haubek, Dorte
    Århus Univ, Dept Dent, Århus, Denmark.
    Presence of JP2 and Non-JP2 genotypes of aggregatibacter actinomycetemcomitans and periodontal attachment loss in adolescents in Ghana2012Inngår i: Journal of Periodontology, ISSN 0022-3492, Vol. 83, nr 12, 1520-1528 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Background: Limited data are reported concerning the presence of A. actinomycetemcomitans and attachment loss (AL) in sub-Saharan countries. The authors investigate the carrier frequency of JP2 and non-JP2 genotypes of A. actinomycetemcomitans and the presence of AL in Ghanaian adolescents and evaluate socioeconomic conditions and oral hygiene practices. Methods: Five hundred individuals (mean +/- SD age: 13.2 +/- 1.5 years) in public and private schools were interviewed about demographic characteristics and oral hygiene practices and were given a full-mouth periodontal examination. Subgingival plaque samples were obtained from periodontal sites around permanent first molars and incisors. The carrier status of A. actinomycetemcomitans at the individual level was determined based on results obtained by cultivation and polymerase chain reaction. Results: The findings of this study show a relatively high carrier rate of JP2 and non-JP2 genotypes of Aggregatibacter actinomycetemcomitans in the Ghanaian adolescent population and the presence of this bacterium is associated with the occurrence of AL. The overall carrier rate of A. actinomycetemcomitans was 54.4%, and the highly leukotoxic JP2 genotype was detected in 8.8% of the study population. A total of 107 (21.4%) individuals had >= 1 tooth with AL >= 3 mm. The majority of the individuals carrying A. actinomycetemcomitans (80.1%) (P<0.001) and of the periodontally diseased individuals (91.6%) (P<0.001) were found in public schools. Conclusions: A. actinomycetemcomitans and AL were frequently found in Ghanaian adolescents. The school type was the strongest predictor of both presence of A. actinomycetemcomitans and AL.

  • 28. Ihalin, R
    et al.
    Asikainen, Sirkka
    Umeå universitet, Medicinsk fakultet, Odontologi, Oral mikrobiologi.
    16S rDNA PCR-denaturing gradient gel electrophoresis in determining proportions of coexisting Actinobacillus actinomycetemcomitans strains.2006Inngår i: Journal of Microbiological Methods, ISSN 0167-7012, Vol. 65, nr 3, 417-424 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Certain serotypes of Actinobacillus actinomycetemcomitans seem to prefer coexistence in vivo. The 16S rDNA PCR-denaturing gradient gel electrophoresis (DGGE) was tested for its capability to distinguish coexisting A. actinomycetemcomitans strains of different serotypes or genetic lineages and to determine their proportions in vitro. The migration pattern of the PCR amplicon from serotype c differed from those of the other serotypes. Contrary to the strains of serotypes c, d, and e, strains of serotypes a, b, and f consistently demonstrated intra-serotype migration patterns similar to each other. Since the migration patterns differed between serotype c and b strains a strain of each was used to determine their proportional representation in a strain mixture. The strains were distinguishable from each other above the 5% PCR-DGGE detection level (12.5 ng DNA/1.5 x 10(6) cells). DGGE provides a promising tool for in vitro studies on the coexistence of different genetic lineages of A. actinomycetemcomitans.

  • 29.
    Ihalin, R
    et al.
    Umeå universitet, Medicinsk fakultet, Odontologi, Oral mikrobiologi.
    Karched, M
    Umeå universitet, Medicinsk fakultet, Odontologi, Oral mikrobiologi.
    Eneslätt, Kjell
    Umeå universitet, Medicinsk fakultet, Odontologi, Oral mikrobiologi.
    Asikainen, Sirkka
    Umeå universitet, Medicinsk fakultet, Odontologi, Oral mikrobiologi.
    Characterization of immunoaffinity purified peptidoglycan-associated lipoprotein of Actinobacillus actinomycetemcomitans.2006Inngår i: Journal of chromatography. B, ISSN 1570-0232, Vol. 831, nr 1-2, 116-125 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Peptidoglycan-associated lipoprotein (PAL) is a highly conserved structural outer membrane protein among Gram-negative bacteria. In some species, it is proinflammatory and released extracellularly. We purified a newly identified PAL (AaPAL) of a periodontal pathogen Actinobacillus actinomycetemcomitans by using AaPAL antipeptide antibodies coupled to immunoaffinity chromatography column. No protein impurities originating in A. actinomycetemcomitans were found in the final product. Sera from patients infected by A. actinomycetemcomitans recognized the purified AaPAL. The present purification method seems to be suitable for isolation of AaPAL and probably PALs of other bacterial species, and applicable in studies investigating proinflammatory mechanisms of A. actinomycetemcomitans.

  • 30.
    Johansson, Elisabeth
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Tandhygienistprogrammet.
    Claesson, Rolf
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Oral mikrobiologi.
    van Dijken, J W V
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Tandhygienistprogrammet.
    Antibacterial effect of ozone on cariogenic bacterial species.2009Inngår i: Journal of Dentistry, ISSN 0300-5712, E-ISSN 1879-176X, Vol. 37, nr 6, 449-453 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Objective: The aim was to evaluate the antibacterial effect of ozone on cariogenic bacterial species with and without the presence of saliva and a possible effect on the salivary proteins.

    Methods: Suspensions of Actinomyces naeslundii (ACTCC 12104T), Lactobacilli casei (N CTC 151) and Streptococcus mutans (NCTC 10449), in salt buffer or in saliva, were exposed to ozone gas delivered by the ozone generator Healozone™ 2130C. Aliquots of the suspensions were taken after 10, 30 and 60s ozone exposures and cultivated on agar plates. Initial number of bacteria per ml was 8.0×107 (SD 2.2×107) (A. naeslundii), 1.0×108 (SD 3.1×106) (L. casei) and 1.0×108 (SD 7.0×105) (S. mutans), respectively. The proteins were separated by SDS electrophoresis and visualized by silver staining.

    Results: In salt buffer 92%, 73% and 64% of the initial numbers of A. naeslundiiS. mutans and L. casei, respectively, were killed already after 10s ozone exposure, while approximately 99.9% of the bacteria were dead after a 60s exposure. After 10 and 30s, but not after 60s exposure to ozone, S. mutans and L. casei were less efficiently killed in saliva compared to the salt buffer. Various saliva proteins were degraded by ozone after a 60s exposure.

    Conclusions:The cariogenic species S. mutansL. casei and A. naeslundii were almost eliminated following 60s of ozone treatment. This killing was reduced in the presence of saliva although increasing the ozone application time to 60s overcame these reductants in saliva. Detection of altered salivary proteins indicates that saliva components constitute additional targets for ozone.

  • 31. Kanasi, E
    et al.
    Dogan, B
    Karched, M
    Thay, B
    Oscarsson, Jan
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Oral mikrobiologi.
    Asikainen, Sirkka
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Oral mikrobiologi.
    Lack of Serotype Antigen in A. actinomycetemcomitans2010Inngår i: Journal of Dental Research, ISSN 0022-0345, E-ISSN 1544-0591, Vol. 89, nr 3, 292-6 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Aggregatibacter actinomycetemcomitans is divided into 6 serotypes. Occurrence of non-serotypeable strains is known, but background reasons are unclear. We hypothesized that non-serotypeable strains represent new serotypes or have altered expression of serotype-specific polysaccharide antigen (S-PA). We first characterized 311 strains from 189 individuals using both immunoassay- and PCR-based serotyping. Next, using natural human infection and rabbit immunization approaches, we clarified whether the phenotypically non-serotypeable strains expressed S-PA. Immunoassay identified serotypes a-f among 216 strains from 159 individuals. The remaining 95 strains from 30 individuals were phenotypically non-serotypeable. Yet, all these strains were identified by PCR-typing as serotype a-, b-, c-, or f. Non-serotypeability was confirmed by Western immunoblot with respective rabbit antisera. Patient sera remained non-reactive with autologous non-serotypeable strains at the serotype-specific region. Rabbit immunization with a phenotypically non-serotypeable strain induced no antibody production against S-PA. Thus, phenotypically non-serotypeable strains did not include novel serotypes, but lacked S-PA expression.

  • 32.
    Kanasi, Eleni
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Oral mikrobiologi.
    Johansson, Ingegerd
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Kariologi.
    Lu, Shulin Charles
    Kressin, Nancy R
    Nunn, Martha E
    Kent, Ralph Jr
    Tanner, Anne CR
    Microbial Risk Markers for Childhood Caries in Pediatricians’ Offices2010Inngår i: Journal of Dental Research, ISSN 0022-0345, E-ISSN 1544-0591, Vol. 89, nr 4, 378-383 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Dental caries in pre-school children has significant public health and health disparity implications. To determine microbial risk markers for this infection, this study aimed to compare the microbiota of children with early childhood caries with that of caries-free children. Plaque samples from incisors, molars, and the tongue from 195 children attending pediatricians’ offices were assayed by 74 DNA probes and by PCR to Streptococcus mutans. Caries-associated factors included visible plaque, child age, race, and snacking habits. Species were detected more frequently from tooth than tongue samples. Lactobacillus gasseri (p < 0.01), Lactobacillus fermentum, Lactobacillus vaginalis, and S. mutans with Streptococcus sobrinus (all p < 0.05) were positively associated with caries. By multifactorial analysis, the probiotic Lactobacillus acidophilus was negatively associated with caries. Prevotella nigrescens was the only species (p < 0.05) significantly associated with caries by the ‘false discovery’ rate. Analysis of the data suggests that selected Lactobacillus species, in addition to mutans streptococci, are risk markers for early childhood caries.

  • 33.
    Karched, M
    et al.
    Umeå universitet, Medicinsk fakultet, Odontologi.
    Paul-Satyaseela, M
    Umeå universitet, Medicinsk fakultet, Odontologi.
    Asikainen, Sirkka
    Umeå universitet, Medicinsk fakultet, Odontologi, Oral mikrobiologi.
    A simple viability-maintaining method produces homogenic cell suspensions of autoaggregating wild-type Actinobacillus actinomycetemcomitans2007Inngår i: Journal of Microbiological Methods, ISSN 0167-7012, Vol. 68, nr 1, 46-51 s.Artikkel i tidsskrift (Annet (populærvitenskap, debatt, mm))
    Abstract [en]

    Tenacious adherence and autoaggregation of wild-type Actinobacillus actinomycetemcomitans strains jeopardize reliability of determined cell concentrations, e.g. for studies on bacteria-host interactions. We first compared the efficacy of two methods, an indirect and a direct method, for homogenizing cell suspensions of a wild-type, autoaggregating (SA269) strain and of a non-autoaggregating laboratory variant (ATCC 43718) used as a reference. Since the direct method left visible clumps in SA269 suspension, only the indirect method was further tested. In serial dilutions of the homogenized cell suspensions of strains SA269 and ATCC 43718, the OD(600) values (R(2)=0.99, R(2)=0.99, respectively) and protein concentrations (R(2)=0.93, R(2)=0.95, respectively) correlated significantly (all P<0.002) with the dilution factor. There were no differences (P>0.05) in the bacterial viable counts between the two strains or between suspending solutions, i.e., PBS and water, the cell concentrations demonstrating 1x10(9) cells/ml at OD(600)=1. Repeated microscopic cell counts did not differ (P>0.05) from each other. Large aggregates occurred as 1% of cell units counted. Dispersing bacterial mass indirectly to solution leads to homogeneous cell suspensions with repeatable cell concentrations. Viability of A. actinomycetemcomitans was also maintained when cells were suspended in water.

  • 34.
    Karched, Maribasappa
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi.
    Ihalin, Rikka
    Eneslätt, Kjell
    Zhong, D
    Oscarsson, Jan
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Oral mikrobiologi.
    Wai, Sun Nyunt
    Umeå universitet, Medicinska fakulteten, Institutionen för molekylärbiologi (Medicinska fakulteten). Umeå universitet, Medicinska fakulteten, Umeå Centre for Microbial Research (UCMR).
    Chen, C
    Asikainen, Sirkka
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi.
    Vesicle-independent extracellular release of a proinflammatory outer membrane lipoprotein in free-soluble form2008Inngår i: BMC Microbiology, ISSN 1471-2180, Vol. 28, nr 8:18Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [sv]

    Aggregatibacter actinomycetemcomitans is an oral bacterium associated with aggressively progressing periodontitis. Extracellular release of bacterial outer membrane proteins has been suggested to mainly occur via outer membrane vesicles. This study investigated the presence and conservation of peptidoglycan-associated lipoprotein (AaPAL) among A. actinomycetemcomitans strains, the immunostimulatory effect of AaPAL, and whether live cells release this structural outer membrane lipoprotein in free-soluble form independent of vesicles. RESULTS: The pal locus and its gene product were confirmed in clinical A. actinomycetemcomitans strains by PCR-restriction fragment length polymorphism and immunoblotting. Culturing under different growth conditions revealed no apparent requirement for the AaPAL expression. Inactivation of pal in a wild-type strain (D7S) and in its spontaneous laboratory variant (D7SS) resulted in pleiotropic cellular effects. In a cell culture insert model (filter pore size 0.02 um), AaPAL was detected from filtrates when strains D7S and D7SS were incubated in serum or broth in the inserts. Electron microscopy showed that A. actinomycetemcomitans vesicles (0.05-0.2 um) were larger than the filter pores and that there were no vesicles in the filtrates. The filtrates were immunoblot negative for a cytoplasmic marker, cyclic AMP (cAMP) receptor protein. An ex vivo model indicated cytokine production from human whole blood stimulated by AaPAL. CONCLUSIONS: Free-soluble AaPAL can be extracellularly released in a process independent of vesicles.

  • 35.
    Kelk, Peyman
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Parodontologi. Umeå universitet, Medicinska fakulteten, Institutionen för klinisk mikrobiologi, Klinisk bakteriologi.
    Abd, Hadi
    Centre for Microbiological Preparedness, Swedish Institute for Infectious Disease Control, Solna, Sweden.
    Claesson, Rolf
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Oral mikrobiologi.
    Sandström, Gunnar
    Centre for Microbiological Preparedness, Swedish Institute for Infectious Disease Control, Solna, Sweden ; Department of Laboratory Medicine, Division of Clinical Microbiology, Karolinska Institute, Stockholm, Sweden.
    Sjöstedt, Anders
    Umeå universitet, Medicinska fakulteten, Institutionen för klinisk mikrobiologi, Klinisk bakteriologi.
    Johansson, Anders
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Parodontologi.
    Inflammatory cell death of human macrophages in response to Aggregatibacter actinomycetemcomitans leukotoxinManuskript (Annet vitenskapelig)
    Abstract [en]

    Aggregatibacter (Actinobacillus) actinomycetemcomitans is a facultative anaerobic gram-negative bacterium associated with severe forms of periodontitis. A leukotoxin, which belongs to the Repeats in Toxin (RTX) family, is believed to be one of its virulence factors and to play an important role in the bacterium's pathogenicity. This toxin selectively kills human leukocytes by inducing apoptosis and lysis. Here we report that leukotoxin-induced cell death of macrophages proceeded through a process that differs from the classical characteristics of apoptosis and necrosis. Interestingly, this process resembled pyroptosis, and resulted in an extensive leukotoxin-induced interleukin-1β (IL-1β) secretion. This activation was mainly mediated by caspase-1 activation, while the levels of mRNA for IL-1β were not affected by the leukotoxin. A similar pattern was seen for IL-18, but the level of that cytokine was about 30 times lower. Both of these cytokines are synthesized as biologically inactive precursors and need active caspase-1 for their activation and secretion. In conclusion, A. actinomycetemcomitans leukotoxin induces a pyroptosis-like cell death in human macrophages and that leads to a specific and excessive pro-inflammatory response. This novel virulence mechanism of the leukotoxin may play an important role in the pathogenic potential of this bacterium.

  • 36.
    Kelk, Peyman
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Parodontologi.
    Claesson, Rolf
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Oral mikrobiologi.
    Hänström, L
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Parodontologi.
    Lerner, Ulf
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Oral cellbiologi.
    Kalfas, S
    Johansson, Anders
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Parodontologi.
    Abundant secretion of bioactive interleukin-1beta by human macrophages induced by Actinobacillus actinomycetemcomitans leukotoxin2005Inngår i: Infection and Immunity, ISSN 0019-9567, E-ISSN 1098-5522, Vol. 73, nr 1, 453-458 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Actinobacillus actinomycetemcomitans produces a leukotoxin that selectively kills human leukocytes. Recently, we reported that macrophages are highly sensitive to leukotoxin and that their lysis involves activation of caspase 1. In this study, we show that leukotoxin also induces the production and release of proinflammatory cytokines from human macrophages. The macrophages were challenged with leukotoxin or lipopolysaccharide (LPS) from A. actinomycetemcomitans or LPS from Escherichia coli, and the production and secretion of interleukin-1beta (IL-1beta), IL-6, and tumor necrosis factor alpha (TNF-alpha) were determined at the mRNA and protein levels by reverse transcription-PCR and enzyme-linked immunosorbent assay, respectively. Leukotoxin (1 to 30 ng/ml) induced abundant production and secretion of IL-1beta, while the effects on IL-6 and TNF-alpha production were limited. Leukotoxin (1 ng/ml) caused a 10-times-higher release of IL-1beta than did LPS (100 ng/ml). The secreted IL-1beta was mainly the bioactive 17-kDa protein. At higher concentrations (>30 ng/ml), leukotoxin caused secretion of mainly inactive cytokine, the 31-kDa pro-IL-1beta. The presence of specific antibodies to IL-1beta or of a caspase 1 inhibitor blocked the secretion and production of the cytokine. Supernatants of leukotoxin-challenged macrophages stimulated bone resorption when tested in a mouse calvarial model. The activity could be blocked by an IL-1 receptor antagonist or specific antibodies to IL-1beta. We concluded that A. actinomycetemcomitans leukotoxin can trigger abundant production and secretion of bioactive IL-1beta by human macrophages, which is mediated by activation of caspase 1.

  • 37.
    Kelk, Peyman
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Parodontologi.
    Johansson, Anders
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Parodontologi.
    Claesson, Rolf
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Oral mikrobiologi.
    Hänström, L
    Kalfas, S
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Oral mikrobiologi.
    Caspase 1 involvement in human monocyte lysis induced by Actinobacillus actinomycetemcomitans leukotoxin2003Inngår i: Infection and Immunity, ISSN 0019-9567, E-ISSN 1098-5522, Vol. 71, nr 8, 4448-4455 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Actinobacillus actinomycetemcomitans, an oral bacterium implicated in the etiology of periodontal diseases, produces a leukotoxin that selectively lyses primate neutrophils and monocytes, the major populations of defense cells in the periodontium. Though lysis requires expression of the receptor lymphocyte function-associated molecule 1 (LFA-1) on the cell surface, not all LFA-1-expressing leukocyte populations are equally susceptible to the toxin. In this study, the susceptibility of human leukocytes to leukotoxin-induced lysis is compared to their expression of LFA-1 and the activity of caspase 1. Cytolysis was determined by the activity of lactate dehydrogenase released from peripheral human leukocytes after 1-h exposure to leukotoxin. Monocytes were lysed at leukotoxin concentrations of > or = 5 ng/ml, while the corresponding values for neutrophils and lymphocytes were approximately 10 times greater. Similar LFA-1 expression was found in all susceptible cell populations irrespective of their degree of sensitivity to the toxin. Exposure of monocytes to leukotoxin increased their caspase 1 activity about fivefold within 10 to 20 min. Presence of the caspase 1 inhibitor Ac-YVAD-CMK significantly blocked the leukotoxin-induced lysis of monocytes only. At sublytic concentrations, leukotoxin induced no apoptotic activity in monocytes, as revealed by the lack of caspase 3 activation and DNA fragmentation. Monocytes are the most lysis-sensitive leukocytes for A. actinomycetemcomitans leukotoxin. Their lysis by this toxin depends on caspase 1 activation and proceeds through a process that differs from classical apoptosis.

  • 38.
    Kieselbach, Thomas
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Oscarsson, Jan
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Oral mikrobiologi.
    Dataset of the proteome of purified outer membrane vesicles from the human pathogen Aggregatibacter actinomycetemcomintans2017Inngår i: Data in Brief, ISSN 2352-3409, Vol. 10, 426-431 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Abstract The Gram-negative bacterium Aggregatibacter actinomycetemcomitans is an oral and systemic pathogen, which is linked to aggressive forms of periodontitis and can be associated with endocarditis. The outer membrane vesicles (OMVs) of this species contain effector proteins such as cytolethal distending toxin (CDT) and leukotoxin (LtxA), which they can deliver into human host cells. The OMVs can also activate innate immunity through NOD1- and NOD2-active pathogen-associated molecular patterns. This dataset provides a proteome of highly purified OMVs from A. actinomycetemcomitans serotype e strain 173. The experimental data do not only include the raw data of the LC-MS/MS analysis of four independent preparations of purified OMVs but also the mass lists of the processed data and the Mascot.dat files from the database searches. In total 501 proteins are identified, of which 151 are detected in at least three of four independent preparations. In addition, this dataset contains the COG definitions and the predicted subcellular locations (PSORTb 3.0) for the entire genome of A. actinomycetemcomitans serotype e strain SC1083, which is used for the evaluation of the LC-MS/MS data. These data are deposited in ProteomeXchange in the public dataset PXD002509. In addition, a scientific interpretation of this dataset by Kieselbach et al. (2015) [2] is available at http://dx.doi.org/10.1371/journal.pone.0138591.

  • 39.
    Konradsson, Katarina
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Tandhygienistprogrammet.
    Claesson, Rolf
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Oral mikrobiologi.
    van Dijken, Jan
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Tandhygienistprogrammet.
    Dental biofilm, gingivitis and interleukin-1 adjacent to approximal sites of a bonded ceramic.2007Inngår i: Journal of Clinical Periodontology, ISSN 0303-6979, E-ISSN 1600-051X, Vol. 34, nr 12, 1062-1067 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Aim: The aim of this study was to investigate in vivo the influence of aged, resin-bonded, ceramic restorations on approximal dental biofilm formation and gingival inflammatory response, associated with and without customary oral hygiene. Material and Methods: In a cross-sectional and in a 10-day experimental gingivitis study, Quigley-Hein plaque index, gingival index (GI), crevicular fluid and its levels of interleukin (IL)-1alpha, -1beta and receptor antagonist were measured at appoximal surfaces of leucite-reinforced bonded ceramic coverages, resin composite restorations and enamel and compared intra-individually in 17 participants. Results: No differences were found between the ceramic, composite and enamel regarding plaque index, GI, levels of IL-1alpha, -1beta and the receptor antagonist. Throughout, higher crevicular fluid amounts were observed at ceramic sites compared with the enamel (p<0.05). In the experimental gingivitis, plaque index, GI, crevicular fluid and its IL-1alpha levels increased significantly. Conclusion: The need for optimal oral hygiene and professional preventive oral health care does not seem to be reduced with regard to approximal surfaces of aged, resin-bonded, leucite-reinforced ceramic restorations in comparison with those of a hybrid, resin composite and enamel.

  • 40.
    Konradsson, Katarina
    et al.
    Umeå universitet, Medicinsk fakultet, Odontologi, Tandhygienistprogrammet.
    Claesson, Rolf
    Umeå universitet, Medicinsk fakultet, Odontologi, Oral mikrobiologi.
    van Dijken, Jan
    Umeå universitet, Medicinsk fakultet, Odontologi, Tandhygienistprogrammet.
    Mutans streptococci and lactobacilli in plaque on a leucite-reinforced dental ceramic and on a calcium aluminate cement.2006Inngår i: Clinical Oral Investigations, ISSN 1432-6981, Vol. 10, nr 3, 175-180 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this in vivo study, the proportions of mutans streptococci and lactobacilli in plaque were examined (1) on proximal surfaces of bonded, leucite-reinforced ceramic crowns and (2) on class V restorations of calcium aluminate cement (CAC). The examined proportions were intraindividually compared with those of resin composite and enamel. Mutans streptococci and lactobacilli in samples from plaque that was accumulated for 10 days on the following surfaces were determined by cultivation on blood agar plates and species-selective plates: (1) proximal leucite-reinforced ceramic crown, class II composite and enamel (n=11); and (2) class V restoration of CAC and composite, and enamel (n=17). Mutans streptococci and lactobacilli in the samples were distributed in three groups: 0, >0-1, and >1% of total bacteria. The surfaces with detected mutans streptococci were similarly distributed between the materials and enamel. The highest proportion of mutans streptococci and lactobacilli were observed on ceramic followed by composite and enamel. A higher proportion of lactobacilli, but not of mutans streptococci, was detected on enamel compared to CAC and composite. However, no significant differences were found between the surfaces. Conclusively, the materials investigated did not show different relative proportions of mutans streptococci and lactobacilli in plaque, compared to enamel.

  • 41. Lakio, L
    et al.
    Lehto, M
    Tuomainen, AM
    Jauhiainen, M
    Malle, E
    Asikainen, Sirkka
    Umeå universitet, Medicinsk fakultet, Odontologi, Oral mikrobiologi.
    Pussinen, PJ
    Pro-atherogenic properties of lipopolysaccharide from the periodontal pathogen Actinobacillus actinomycetemcomitans.2006Inngår i: Journal of Endotoxin Research, ISSN 0968-0519, Vol. 12, nr 1, 57-64 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    An association between cardiovascular and periodontal disease may be due to lipopolysaccharide (LPS)-promoted release of inflammatory mediators, adverse alterations of the lipoprotein profile, and an imbalance in cholesterol homeostasis. Since periodontopathogenic potential differs between serotypes of a major periodontal pathogen, Actinobacillus actinomycetemcomitans, we studied the pro-atherogenic properties of LPS preparations from serotypes b and d strains on macrophages (RAW 264.7). A. actinomycetemcomitans LPS preparations induced a time-dependent release of tumor necrosis factor-alpha (TNF-alpha) and interleukin-1beta (IL-1beta). LPS induced foam cell formation and cholesteryl ester accumulation from native low density lipoprotein in the following order: A. actinomycetemcomitans strains JP2 (serotype b) > Y4 (serotype b) > IDH781 (serotype d). mRNA expression levels of scavenger receptor class B, type-I, and ATP-binding cassette transporter-1, receptors mediating cholesterol efflux from macrophages, were decreased by LPS preparations. The results suggest that the pro-atherogenic potential of A. actinomycetemcomitans LPS may depend on the infecting strain and correlate with the periodontopathogenic potential of the pathogen.

  • 42. Lakio, L
    et al.
    Paju, S
    Alfthan, G
    Tiirola, T
    Asikainen, Sirkka
    Umeå universitet, Medicinsk fakultet, Odontologi, Oral mikrobiologi.
    Pussinen, PJ
    Actinobacillus actinomycetemcomitans serotype d-specific antigen contains the O antigen of lipopolysaccharide.2003Inngår i: Infection and Immunity, ISSN 0019-9567, Vol. 71, nr 9, 5005-5011 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Actinobacillus actinomycetemcomitans is a gram-negative, facultatively anaerobic bacterium which is associated especially with aggressive forms of periodontitis. Contradictory results on the localization of the A. actinomycetemcomitans serotype-specific antigen have been reported. The aim of the present study was to characterize the A. actinomycetemcomitans serotype d-specific antigen. The antigen was isolated by affinity chromatography. The affinity column was prepared from immunoglobulin G isolated from rabbit antiserum raised against A. actinomycetemcomitans serotype d. The isolated antigen was analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, Western blotting, and silver staining, all of which revealed a ladder-like structure typical for the O antigen of lipopolysaccharide (LPS). In a displacement enzyme-linked immunosorbent assay (ELISA), the isolated antigen displaced in a concentration-dependent manner the binding of the polyclonal rabbit antiserum raised against A. actinomycetemcomitans serotype d to the competing whole-cell serotype d antigen. The isolated antigen contained LPS, and an equal concentration of LPS isolated from A. actinomycetemcomitans serotype d gave a similar displacement curve in the ELISA. In order to test the immunogenic properties of the isolated antigen, it was used to immunize a rabbit. The antiserum raised against the isolated antigen displayed specificity in Western blotting and ELISA similar to that of antibody raised against LPS isolated from A. actinomycetemcomitans serotype d. In conclusion, our results show that the A. actinomycetemcomitans serotype d-specific antigen contains the O-antigenic structure of LPS.

  • 43.
    Mahdavi, Jafar
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Oral mikrobiologi.
    Helicobacter pylori adhesion and patho-adaptation: the role of BabA and SabA adhesins in persistent infection and chronic inflammation2004Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Helicobacter pylori (H. pylori) is a human-specific gastric pathogen which is responsible for a spectrum of diseases ranging from superficial gastritis to gastric and duodenal ulceration, and which is also highly associated with gastric cancer. The pathogenesis of severe gastric disorders caused by H. pylori is multifactorial and involves complex interactions between the microbe and the gastric mucosa. H. pylori expresses several adhesion proteins. These molecules have important roles in the establishment of persistent infection and chronic inflammation, which cause tissue damage.

    The aim of this thesis was to study the attachment of this bacterium to human gastric epithelium, mediated by blood group antigens in both health and disease. One of the bestcharacterized H. pylori adhesins is the histo-blood group antigen binding adhesin (BabA), which binds specifically to the Lewis b antigen (Leb) in the gastric mucosa.

    A protective mucus layer lines the stomach. The mucosal glycosylation patterns (GPs) vary between different cell lineages, different locations along the gastrointestinal (GI) tract and different developmental stages. In addition, GPs undergo changes during malignant transformation. MUC5AC is a mucin molecule produced by the surface epithelium. Three distinctly different types of human gastrointestinal tissue were studied by bacterial adherence analysis in situ. MUC5AC is the most important carrier of Leb and the new results demonstrate that it forms major receptors for H. pylori adherence.

    By analysing an H. pylori babA-deletion mutant, a novel adhesin-receptor binding mode was found. Surprisingly, the mutant bound efficiently to both human gastric mucosa and to gastric mucosa of Leb transgenic mice. The sialylated and fucosylated blood group antigen, sialyl-dimeric-Lewis x (sdiLex), was structurally identified as the new receptor. A positive correlation was found between adherence of H. pylori to sialyl-Lewis x (sLex) and elevated levels of inflammation response in the human gastric mucosa. These results were supported by detailed analysis of sialylated and fucosylated blood group antigen glycosylation patterns and, in addition, in situ bacterial adherence to gastric mucosa of experimentally challenged Rhesus monkey. The cognate sialic acid-binding adhesin (SabA) was purified by the retagging technique, and the corresponding sabA-gene was identified.

    H. pylori lipopolysaccharide (LPS) contains various Lewis blood group antigens such as Lewis x (Lex) and Lewis y (Ley). Additional bacterial adherence modes, which are independent of the BabA and/or SabA adhesins, could possibly be mediated by Lex interactions. Adherence of a clinical isolate and its corresponding Lex mutant to human gastric mucosa with various gastric pathologies was studied in situ. The results suggest that H. pylori LPS plays a distinct but minor role in promotion of bacterial adhesion.

    Taken together, the results suggest mechanisms for continuous selection of H. pylori strains, involving capacity to adapt to changes in the local environment such as shifts in cell differentiation and associated glycosylation patterns. Adherence of H. pylori is dependent on both the BabA and the SabA adhesin. Multi-step dependent attachment mechanisms may direct the microbes to distinct ecological niches during persistent infections, driving the chronic inflammation processes further toward the development of peptic ulcer disease and/or malignant transformation.

    Key words: H. pylori, BabA, adhesin, Lewis b, MUC5AC, sialyl-dimeric-Lewis x, chronic inflammation, SabA, Lewis x, LPS.

  • 44.
    Mahdavi, Jafar
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Oral mikrobiologi.
    Borén, Thomas
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Oral mikrobiologi.
    Vandenbroucke-Grauls, Christina
    Appelmelk, Ben J
    Limited role of lipopolysaccharide Lewis antigens in adherence of Helicobacter pylori to the human gastric epithelium2003Inngår i: Infection and Immunity, ISSN 0019-9567, E-ISSN 1098-5522, Vol. 71, nr 5, 2876-2880 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In vitro and in vivo studies from various groups have suggested that Helicobacter pylori lipopolysaccharide (LPS) Lewis x (Lex) antigens mediate bacterial adhesion. We have now reevaluated this hypothesis by studying the adherence in situ of H. pylori strain 11637 and its corresponding Lex-negative rfbM mutant to human gastric mucosa from patients (n 22) with various gastric pathologies. Significant binding of the parent strain was observed in only 8 out of 22 sections; in four out of eight patients, the Lex-negative mutant bound less well. One of these four patients displayed no gastric abnormalities, and the other three showed dysplasia, metaplasia, and adenocarcinoma, respectively; hence, we are unable to define the circumstances under which LPS-mediated adhesion takes place. We conclude that H. pylori LPS plays a distinct but minor role in adhesion.

  • 45.
    Mahdavi, Jafar
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Oral mikrobiologi.
    Sondén, Berit
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Oral mikrobiologi.
    Hurtig, Marina
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Oral mikrobiologi.
    Olfat, Farzad O
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Oral mikrobiologi.
    Forsberg, Lina
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Oral mikrobiologi.
    Roche, Niamh
    Ångström, Jonas
    Larsson, Thomas
    Teneberg, Susann
    Karlsson, Karl-Anders
    Altraja, Siiri
    Wadström, Torkel
    Kersulyte, Dangeruta
    Berg, Douglas E
    Dubois, Andre
    Petersson, Christoffer
    Magnusson, Karl-Eric
    Norberg, Thomas
    Lindh, Frank
    Lundskog, Bertil B
    Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk biovetenskap.
    Arnqvist, Anna
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Oral mikrobiologi. Umeå universitet, Medicinska fakulteten, Molekylärbiologi (Teknat- och Medfak).
    Hammarström, Lennart
    Borén, Thomas
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Oral mikrobiologi.
    Helicobacter pylori SabA adhesin in persistent infection and chronic inflammation2002Inngår i: Science, ISSN 0036-8075, Vol. 297, nr 5581, 573-578 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Helicobacter pylori adherence in the human gastric mucosa involves specific bacterial adhesins and cognate host receptors. Here, we identify sialyl-dimeric-Lewis x glycosphingolipid as a receptor for H. pylori and show that H. pylori infection induced formation of sialyl-Lewis x antigens in gastric epithelium in humans and in a Rhesus monkey. The corresponding sialic acid-binding adhesin (SabA) was isolated with the "retagging" method, and the underlying sabA gene (JHP662/HP0725) was identified. The ability of many H. pylori strains to adhere to sialylated glycoconjugates expressed during chronic inflammation might thus contribute to virulence and the extraordinary chronicity of H. pylori infection.

  • 46.
    Nylander, Åsa
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Oral mikrobiologi.
    Forsgren, Nina
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Kariologi.
    Persson, Karina
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi.
    Structure of the C-terminal domain of the surface antigen SpaP from the caries pathogen Streptococcus mutans2011Inngår i: Acta Crystallographica. Section F: Structural Biology and Crystallization Communications, ISSN 1744-3091, E-ISSN 1744-3091, Vol. 67, 23-26 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    SpaP is a 1500-residue adhesin expressed on the surface of the caries-implicated bacterium Streptococcus mutans. SpaP is a member of the antigen I/II (AgI/II) family of proteins expressed by oral streptococci. These surface proteins are crucial for the incorporation of streptococci into dental plaque. The structure of the C-terminal domain of SpaP (residues 1136-1489) was solved and refined to 2.2 Å resolution with six molecules in the asymmetric unit. Similar to a related AgI/II structure, SpaP is stabilized by isopeptide bonds between lysine and asparagine side chains.

  • 47.
    Nylander, Åsa
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Oral mikrobiologi.
    Svensäter, Gunnel
    Malmö Högskola.
    Senadheera, Dilani B.
    University of Toronto.
    Cvitkovitch, Dennis G.
    University of Toronto.
    Davies, Julia R.
    Malmö Högskola.
    Persson, Karina
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Structural and functional analysis of the N-terminal domain of the Streptococcus gordonii adhesin Sgo07072013Inngår i: PLoS ONE, ISSN 1932-6203, Vol. 8, nr 5, e63768- s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The commensal Streptococcus gordonii expresses numerous surface adhesins with which it interacts with other microorganisms, host cells and salivary proteins to initiate dental plaque formation. However, this Gram-positive bacterium can also spread to non-oral sites such as the heart valves and cause infective endocarditis. One of its surface adhesins, Sgo0707, is a large protein composed of a non-repetitive N-terminal region followed by several C-terminal repeat domains and a cell wall sorting motif. Here we present the crystal structure of the Sgo0707 N-terminal domains, refined to 2.1 Å resolution. The model consists of two domains, N1 and N2. The largest domain, N1, comprises a putative binding cleft with a single cysteine located in its centre and exhibits an unexpected structural similarity to the variable domains of the streptococcal Antigen I/II adhesins. The N2-domain has an IgG-like fold commonly found among Gram-positive surface adhesins. Binding studies performed on S. gordonii wild-type and a Sgo0707 deficient mutant show that the Sgo0707 adhesin is involved in binding to type-1 collagen and to oral keratinocytes.

  • 48. Ohno, Tomoyuki
    et al.
    Vallström, Anna
    Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk kemi och biofysik. Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Oral mikrobiologi. Umeå universitet, Medicinska fakulteten, Umeå Centre for Microbial Research (UCMR).
    Rugge, Massimo
    Ota, Hiroyoshi
    Graham, David Y
    Arnqvist, Anna
    Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk kemi och biofysik. Umeå universitet, Medicinska fakulteten, Umeå Centre for Microbial Research (UCMR).
    Yamaoka, Yoshio
    Effects of blood group antigen-binding adhesin expression during Helicobacter pylori infection of Mongolian gerbils2011Inngår i: Journal of Infectious Diseases, ISSN 0022-1899, Vol. 203, nr 5, 726-735 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Helicobacter pylori outer membrane proteins, such as the blood group antigen-binding adhesin (BabA), are associated with severe pathological outcomes. However, the in vivo role of BabA during long-term infection is not clear. In this study, Mongolian gerbils were infected with H. pylori and necropsied continuously during 18 months. Bacterial clones were recovered and analyzed for BabA expression, Leb-binding activity, and adhesion to gastric mucosa. BabA expression was completely absent by 6 months post-infection. Loss of BabA expression was attributable to nucleotide changes within the babA gene that resulted in a truncated BabA. In response to the infection, changes in the epithelial glycosylation pattern were observed that were similar to responses observed in humans and monkeys. Furthermore, infections with BabA-expressing and BabA-nonexpressing H. pylori showed no differences in colonization, but infection with the BabA-expressing strain exhibited histological changes and increased inflammatory cell infiltration. This suggests that BabA expression contributes to severe mucosal injury.

  • 49.
    Ohno, Tomoyuki
    et al.
    Department of Medicine-Gastroenterology, Michael E. DeBakey Vetrans Medical Center and Baylor College of Medicine, Houston, Texas, USA.
    Vallström, Anna
    Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk kemi och biofysik. Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Oral mikrobiologi.
    Wu, MJ
    Rugge, Massimo
    Department of Diagnostic Science and Special Therapies (Pathology Unit), University of Padova, Padova, Italy.
    Ota, Hiroyoshi
    Department of Biomedical Laboratory Sciences, School of Health Sciences, Shinshu University School of Medicine, Matsumoto, Japan.
    Graham, David Y
    Department of Medicine-Gastroenterology, Michael E. DeBakey Vetrans Medical Center and Baylor College of Medicine, Houston, Texas, USA.
    Arnqvist, Anna
    Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk kemi och biofysik.
    Yamaoka, Yoshio
    Department of Medicine-Gastroenterology, Michael E. DeBakey Vetrans Medical Center and Baylor College of Medicine, Houston, Texas, USA and Department of Environmental and Preventive Medicine, Oita University Faculty of Medicine, Yufu, Japan.
    Effects of BabA expression during H. pylori infection of Mongolian gerbilsManuskript (Annet vitenskapelig)
    Abstract [en]

    Objective: Helicobacter pylori outer membrane proteins, such as the BabA adhesin are associated with severe pathological outcome.  However, the in vivo role of the BabA adhesin during long-term infection is not clear.  Design and Setting: Mongolian gerbils were inoculated with the H. pylori TN2GF4 and were necropsied at 1, 3, 6, and 18 months.  Main outcome measures: Bacterial clones recovered from the infected gerbils were evaluated by immunoblot for BabA expression, radioimmunoassay for Leb-binding, and bacterial binding to gastric tissue.  H1 antigen expression and the increase in sialylation levels were monitored by immunohistochemistry.  Results: BabA expression increased, then progressively decreased, and was completely absent by 6 months post-infection.  Loss of BabA expression was caused by nucleotide changes/deletions within the babA gene that resulted in a truncated BabA.  Infection with a BabA-expressing H. pylori caused severe mucosal injury, whereas infection with a BabA non-expressing strain caused only mild inflammation.  In response to the infection, changes in the epithelial glycosylation pattern were observed, similar to responses observed in humans and monkeys.  Conclusion: Down-regulation of BabA is probably a result of adaptation to the host response during long-term H. pylori infection.  BabA expression is most likely not essential for colonisation, but for the obtained gerbil host response, which confirms the role of BabA adhesin as a virulence factor and its impact in the induction of a severe inflammatory response.  The changes in glycosylation of gastric mucosa demonstrate the relevance of the Mongolian gerbil as a model for H. pylori infection and host responses.

  • 50. Oittinen, J
    et al.
    Kurki, T
    Kekki, M
    Kuusisto, M
    Pussinen, P
    Vilkuna-Rautiainen, T
    Nieminen, A
    Asikainen, Sirkka
    Umeå universitet, Medicinsk fakultet, Odontologi, Oral mikrobiologi.
    Paavonen, J
    Periodontal disease and bacterial vaginosis increase the risk for adverse pregnancy outcome.2005Inngår i: Infectious diseases in obstetrics and gynecology, ISSN 1064-7449, Vol. 13, nr 4, 213-216 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    OBJECTIVES: To determine whether periodontal disease or bacterial vaginosis (BV) diagnosed before pregnancy increase the risk for adverse pregnancy outcome. METHODS: We enrolled a total of 252 women who had discontinued contraception in order to become pregnant. The first 130 pregnant women were included in the analyses. RESULTS: Multivariate analysis showed a strong association between periodontal disease and adverse pregnancy outcome (OR 5.5, 95% confidence interval 1.4-21.2; p = 0.014), and a borderline association between BV and adverse pregnancy outcome (OR 3.2, 95% confidence interval 0.9-10.7; p = 0.061). CONCLUSION: Our study suggests that pre-pregnancy counseling should include both oral and vaginal examinations to rule out periodontal disease and BV. This may ultimately have an impact on antenatal healthcare, and decrease the risk for adverse pregnancy outcome.

12 1 - 50 of 80
RefereraExporteraLink til resultatlisten
Permanent link
Referera
Referensformat
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annet format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annet språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf