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Biomedical subjects

I Olsen

Publications and source records attributed to I Olsen.

At least 109 records · Page 6Linked to original sources
PubMed1995

Detection of tet(M) and tet(O) using the polymerase chain reaction in bacteria isolated from patients with periodontal disease.

The polymerase chain reaction was used to examine 114 tetracycline-resistant anaerobic and facultative anaerobic bacterial isolates from patients with periodontal disease for the tet(M) and tet(O) genes. A 740-base-pair fragment of the tet(M) gene was amplified from 84 of 114 isolates, and a 519-base-pair fragment of the tet(O) gene was amplified from 13 streptococcal isolates. Six of 7 tetracycline-resistant isolates of Veillonella spp. and tetracycline-resistant isolates of Eubacterium spp. (n = 3), Eubacterium saburreum (n = 1), Streptococcus intermedius (n = 5) and Gemella morbillorum (n = 2) all harbored the tet(M) gene. The tet(M) and tet(O) negative as well as selected positive isolates were tested for the tet(K) and tet(L) genes using DNA probes. All isolates of Staphylococcus spp. (n = 11) hybridized with the tet(K) probe. None of the isolates tested hybridized with the probe for tet(L). This is the first report of the tet(M) gene in the facultative bacterium G. morbillorum and in E. saburreum.

Bacteria, Anaerobic↗
PubMed1995

Population genetic analysis of oral treponemes by multilocus enzyme electrophoresis.

Seventeen treponemes recently isolated from necrotic pulps, periodontal and periapical infections and 17 previously well characterized oral treponemal strains were analyzed by multilocus enzyme electrophoresis. Ten genetic loci were characterized on the basis of the electrophoretic mobilities of their enzymatic products. All loci were polymorphic. The average number of alleles per locus was 7.8. The genetic diversity among the electrophoretic types at each locus ranged from 0.624 to 0.836 with a mean genetic diversity per locus of 0.751. The 34 strains represented 34 electrophoretic types, constituting 6 main divisions (I-VI) separated at genetic distances greater than 0.75. Several of the previously characterized treponemes revealed multiple bands of enzyme activity at several loci, indicating that they were not pure. The characterized strains usually clustered within established species, whereas fresh clinical isolates overlapped species borders. There was a large genetic difference between some reference and clinical strains, indicating that the latter may contain undescribed species. Treponema socranskii and Treponema denticola strains clustered in distinct divisions (IV and V, respectively), with the exception of T. denticola strain FDC 51B2 and T. socranskii subsp. paredis strain VPI D46CPE1, both previously well described. This indicated that the taxonomic assignment of these 2 strains should be reconsidered.

Alleles↗
PubMed1995

Identity of 1:2:1 and 2:4:2 subgingival spirochetes by DNA hybridization.

A group of 1:2:1 and 2:4:2 subgingival spirochetes, well characterized by transmission electron microscopy, biochemical tests, cellular fatty acid and carbohydrate analyses, and ribotyping, was recently suggested to represent new treponemal species. The present study used DNA hybridization to examine this possibility. When DNA of a representative strain (no. 16) of the 8 1:2:1 spirochetes examined was labeled by iodination, it showed, after S1 nuclease treatment, from 58 to 104% (average 76%) homology with DNA from the 1:2:1 spirochetes, 94% homology with DNA from the type strain of Treponema socranskii and of T. socranskii subsp. socranskii, i.e., ATCC 35536T, and 62% homology with DNA from T. socranskii subsp. buccale, strain ATCC 35534T. Similarly treated DNA from a representative strain (no. 3) of 8 2:4:2 spirochetes exhibited from 90 to 105% (average 97%) homology with DNA from the 2:4:2 spirochetes, and 85% and 87% homology, respectively, with DNA from Treponema denticola strains ATCC 33520 and FDC T1. There was a negligible degree of homology between the 1:2:1 and 2:4:2 spirochetes. Thus, all the 2:4:2 spirochetes belonged to T. denticola. 1:2:2 strains with DNA homology levels >70% (5 strains) belonged to T. socranskii or T. socranskii subsp. socranskii, while those with homology levels from 58 to 63% (3 strains) most likely belonged to other subspecies of T. socranskii.

Bacterial Typing Techniques↗
PubMed1995

Tetracycline-resistant micro-organisms recovered from patients with refractory periodontal disease.

Tetracycline in combination with scaling and root planing is frequently used to treat refractory periodontal disease. This study examined tetracycline resistance in bacteria recovered from periodontal pockets of patients with refractory periodontitis. Bacterial isolates resistant to 10 micrograms/ml of tetracycline were isolated from plaque samples of 17 patients, of whom 6 had received tetracycline within 8 weeks prior to sampling. Minimal inhibitory concentrations (MICs) of tetracycline and minocycline were determined by agar dilution. In the 6 patients who had received tetracycline, a mean of 22.9% (+/- 38.2) of the total cultivable subgingival flora were resistant to tetracycline, compared with a mean of 7.2% (+/- 8.5) in the untreated group. Although various organisms were isolated, in most patients, the tetracycline-resistant organisms were dominated by Streptococcus spp. Overgrowth of Candida was found in one patient, and of Enterobacteriaceae in another patient, while small numbers of yeast or Staphylococcus spp. were isolated from the plaque samples of 9 others. 3 out of 4 patients who did not respond to tetracycline treatment had a variety of tetracycline-resistant anaerobic Gram-negative rods present. No correlation was found between increased proportions of tetracycline resistance in the whole bacterial sample and the presence of resistant periodontal pathogens.

Adult↗
PubMed1995

Bacteremia in conjunction with endodontic therapy.

This study characterizes oral microorganisms believed to have spread from the root canal into the blood stream during and after endodontic therapy of teeth with Asymptomatic apical periodontitis. Microbiological samples were taken under aseptic conditions from the root canal of 26 single-rooted teeth in 26 patients. In the endodontic treatment of 13 of the patients (Group 1), the first 3 reamers, sizes 15, 20 and 25, were used to a level 2 mm beyond the apical foramen. In the other 13 patients (Group 2), the instrumentation ended inside the root canal 1 mm short of the apical foramen. Blood samples were taken from the patients during the instrumentation and 10 min after the treatment was completed. Anaerobic microorganisms were isolated from all root canals. In 7 patients of Group 1, Propionibacterium acnes, Peptostreptococcus prevotii, Fusobacterium nucleatum, Prevotella intermedia and Saccharomyces cerevisiae were recovered from the blood. In 4 patients of Group 2, P. intermedia, Actinomyces israelii, Streptococcus intermedius and Streptococcus sanguis were isolated from the blood. Biochemical tests and antibiograms revealed that the isolates from the root canal and blood had identical profiles within the patients, strongly suggesting that the microorganisms isolated from the blood had the root canal as their source.

Actinomyces↗
PubMed1995

Expression of lymphocyte function-associated antigen 3 in oral lichen planus.

OBJECTIVE: The expression pattern of lymphocyte function-associated antigen 3 (LFA-3) in the buccal mucosa of oral lichen planus (OLP) patients was compared to that of healthy controls to investigate the possible role of LFA-3 in cell interactions within OLP lesions. MATERIALS AND METHODS: Samples of buccal mucosa from 17 clinically healthy individuals and 17 OLP lesions were analysed. Expression of LFA-3, CD2, CD3 and CD14 was visualized by an immunoperoxidase technique and assessed microscopically. RESULTS: In healthy buccal mucosa LFA-3 was expressed on keratinocytes, Langerhans cells within the epithelium and on endothelial cells in the lamina propria. In OLP patients a similar pattern of LFA-3 staining was observed. In addition, cytoplasmic LFA-3 without accompanying surface staining, was seen on a subpopulation of macrophage-like cells. Substantial amounts of LFA-3 also appeared to be associated with non-cellular components of the extracellular matrix within the inflammatory infiltrate. CONCLUSIONS: We have obtained evidence for a previously undescribed localization of LFA-3 within macrophages, and have observed that expression of LFA-3 is apparently elevated within OLP lesions. LFA-3 may play an important role in the pathogenesis of OLP.

CD2 Antigens↗
PubMed1995

Expression of ectopeptidases in scleroderma.

OBJECTIVES: To examine the expression and concentrations of three ectopeptidases likely to be involved in regulating the functional levels of adhesion molecules and the turnover of connective tissue components, in patients with scleroderma (systemic sclerosis) (SSc) and in normal individuals. METHODS: Monoclonal antibodies against these antigens were used for immunoperoxidase staining of cryostat skin sections and for flow cytometric (fluorescence activated cell sorter) analysis of cultured dermal fibroblasts grown from SSc patients and normal controls. RESULTS: Although neutral endopeptidase-24.11 (NEP) (CD10) was not detected in either SSc or normal skin, aminopeptidase N (APN) (CD13) and dipeptidyl peptidase IV (DPPIV) (CD26) were both readily visualised. However, DPPIV appeared to be present in smaller concentrations in the SSc biopsy specimens. Moreover, while fibroblasts grown in vitro from both SSc and normal skin also had similar concentrations of APN, the expression of DPPIV in the cultured SSc cells was found to be very much less than that present in the normal fibroblasts. It is noteworthy that NEP, which was not detected in the tissue sections, was nevertheless readily detected in fibroblasts in culture. CONCLUSIONS: These results show that a number of cell surface proteases are expressed by dermal fibroblasts both in vivo and in vitro, and it is suggested that the marked downregulation of DPPIV in SSc could be at least partly responsible for the increased concentrations of adhesion molecules and matrix proteins associated with the molecular pathology of this disease.

Adolescent↗
PubMed1994

Expression and shedding of intercellular adhesion molecule 1 and lymphocyte function-associated antigen 3 by normal and scleroderma fibroblasts. Effects of interferon-gamma, tumor necrosis factor alpha, and estrogen.

OBJECTIVE: To examine intercellular adhesion molecule 1 (ICAM-1) and lymphocyte function-associated antigen 3 (LFA-3) in cultures of normal and systemic sclerosis (SSc) dermal fibroblasts. METHODS: The surface and soluble forms of ICAM-1 and LFA-3 were measured by flow cytometry and capture enzyme-linked immunosorbent assay, respectively. RESULTS: Surface ICAM-1 was significantly higher on SSc fibroblasts compared with normal controls. Beta-estradiol did not directly enhance ICAM-1 or LFA-3 expression in either normal or SSc cells, but significantly augmented the cytokine-induced increase in ICAM-1. Soluble ICAM-1 (sICAM-1) and sLFA-3 were detected in fibroblast cultures. While no difference was found in the level of sLFA-3, the shedding of sICAM-1 was significantly increased (P < 0.001) in cells from SSc patients. CONCLUSION: SSc fibroblasts express intrinsically elevated levels of surface ICAM-1 and release higher levels of sICAM-1 in vitro. Increased expression of ICAM-1 by interferon-gamma and tumor necrosis factor alpha alone, and the further induction in combination with beta-estradiol may underlie an aspect of fibroblast dysfunction in SSc and the female predisposition to the disease.

Antigens, CD↗
PubMed1994

Regulation of CD2-mediated heterotypic interactions of murine T lymphocytes.

In this study we have investigated the expression and function of the murine CD2 receptor in T cells. The surface level of CD2 increased between 300 and 400% when T cells were activated, which also induced a rapid increase of nearly 40-fold in the steady-state levels of CD2 mRNA. Although the activated lymphocytes were found to internalize and degrade nearly 50% of membrane-bound CD2, in addition to shedding the CD2 receptor from the cell surface, this does not account for the discrepancy between the increase in mRNA and antigen levels during activation. These findings suggest that the expression of CD2 is also regulated by post-transcriptional processes which control the translational efficiency of the CD2 message. Activation of T cells enhanced their interaction with mesenchymal cell targets (fibroblasts) via a CD2-dependent adhesion pathway which was not inhibited by the anti-mouse CD48 (sgp-60) mAb OX78, the only counter-receptor thus far identified on other cells as a ligand for the mouse CD2 receptor. Moreover, since murine fibroblasts were found not to express CD48, our results implicate a novel ligand for CD2, possibly a homologue of the human LFA-3. This new pathway of heterotypic T cell interaction would be facilitated by utilization of the large intracellular pool of CD2 transcripts to up-regulate CD2 expression and, as this receptor is a major signal-transducing molecule, would further enhance T cell activation and increase CD2-mediated adhesion.

Animals↗
PubMed1994

Interactions between cardiomyocytes and lymphocytes in tissue culture: an in vitro model of inflammatory heart disease.

Inflammation of heart tissue is a pathological feature of infections and autoimmune diseases, and sometimes also occurs after heart transplantation. In these situations, the invasive infiltration of lymphocytes, most probably cytotoxic (CD8-positive) T cells, is likely to be the cause of cardiac damage, as shown by the results of studies on experimental animal models of myocarditis. However, the cellular and molecular events underlying the interactions between lymphocytes and cardiomyocytes have hitherto not been investigated. In the present study we describe a new procedure for obtaining ventricular heart cells from neonatal mice and for maintaining them in serum-free medium in culture dishes coated with certain matrix components. Such cells adhered, spread, and were functionally active since they started a beating rhythm after 2 days. T and B cells which had been surface-labelled with biotin were added to these cells and lymphocyte adhesion was measured. The number of lymphocytes which became bound to the cardiomyocytes was calculated from the amount of biotin which remained associated with the monolayer after extensive washing to remove non-adherent cells. Colourimetric detection, using a streptavidin-peroxidase reagent, showed that an average of approximately 10 activated lymphocytes bound per heart cell, four times greater than the attachment of resting T cells. The results of this study provide a reproducible basis for using monoclonal antibodies which react against lymphocyte surface receptors and their cognate ligands to identify the specific adhesion molecules involved in heart cell recognition and interaction.

Animals↗
PubMed1994

Excess matrix accumulation in scleroderma is caused partly by differential regulation of stromelysin and TIMP-1 synthesis.

Scleroderma (systemic sclerosis: SSc) is an autoimmune disorder in which excessive extracellular matrix is deposited in skin and internal organs. Because of the importance of metalloproteinases in the turnover of connective tissue, in this study we have developed a novel procedure which utilises flow cytometry (FACS) to measure the production of stromelysin (MMP-3), gelatinase A (MMP-2), and the proteinase inhibitor TIMP-1, by SSc skin fibroblasts. In the presence of monensin, which prevents the secretion of these matrix proteins, there was a similar intracellular accumulation of gelatinase A in normal and SSc cells. However, whereas stromelysin levels also increased in the normal cells, no net synthesis could be detected in the SSc fibroblasts. In marked contrast, the synthesis of TIMP-1 was 50% greater in the SSc cells than in the normal fibroblasts. Our results thus show unequivocally, for the first time, that cells from SSc patients simultaneously produce less stromelysin but substantially higher amounts of TIMP-1 than do normal dermal fibroblasts, suggesting that abnormalities in the regulation of the matrix enzymes and their inhibitors play an important part in the molecular pathology of SSc.

Adolescent↗
PubMed1994

The tet(Q) gene in bacteria isolated from patients with refractory periodontal disease.

Twenty-two tetracycline-resistant (tetr) anaerobic and facultative anaerobic bacteria isolated from periodontal pockets of 12 patients with refractory periodontitis were examined for the presence of the Tet Q determinant by DNA-DNA hybridization. Dot blots of bacterial DNA were tested with an intragenic digoxigenin-labelled tet(Q) probe consisting of a 1.45 kb EcoRI/PvuII fragment from plasmid pNFD13-2. Southern blots of chromosomal DNA digested with the restriction enzyme EcoRI were also examined. The tet(Q) probe hybridized with DNA from 8 of the 22 tetr strains, including 2 Prevotella intermedia strains and one strain each of Prevotella nigrescens, Prevotella loescheii, Prevotella veroralis and Prevotella melaninogenica. The tetr strains of Mitsuokella dentalis and Capnocytophaga ochracea also hybridized with the probe. The lack of discernible plasmid DNA in all the probe-positive isolates suggests that these tetracycline-resistance genes were chromosomally encoded. The probe hybridized with a different size fragment in all the isolates. This study extends the number of species that carry the tet(Q) gene to include several outside the genera Prevotella and Bacteroides.

Anti-Bacterial Agents↗
PubMed1994

Systemic diseases caused by oral microorganisms.

Human endodontic and periodontal infections are associated with complex microfloras in which approximately 150, (in apical periodontitis) and 350 (in marginal periodontitis) bacterial species have been encountered. These infections are predominantly anaerobic, with gram-negative rods being the most common isolates. The anatomic closeness of this microflora to the bloodstream can facilitate bacteremia and systemic spread of bacterial by-products and immunocomplexes. A variety of clinical procedures such as tooth extraction, periodontal and endodontic treatment, may cause translocation of microorganisms from the oral cavity to the bloodstream. The microorganisms that gain entrance to the blood circulate throughout the body, but are usually eliminated by the host (reticuloendothelial system) within minutes. However, in patients with ineffective heart valves or vascular diseases, bacteremia can be a potential danger, leading most commonly to infective endocarditis and myocardial or cerebral infarction. Other forms of systemic diseases such as brain abscesses, hematological infections and implant infections have also been related to oral microorganisms.

Bacteremia↗
PubMed1994

Phylogeny of Bacteroides, Prevotella, and Porphyromonas spp. and related bacteria.

The phylogenetic structure of the bacteroides subgroup of the cytophaga-flavobacter-bacteroides (CFB) phylum was examined by 16S rRNA sequence comparative analysis. Approximately 95% of the 16S rRNA sequence was determined for 36 representative strains of species of Prevotella, Bacteroides, and Porphyromonas and related species by a modified Sanger sequencing method. A phylogenetic tree was constructed from a corrected distance matrix by the neighbor-joining method, and the reliability of tree branching was established by bootstrap analysis. The bacteroides subgroup was divided primarily into three major phylogenetic clusters which contained most of the species examined. The first cluster, termed the prevotella cluster, was composed of 16 species of Prevotella, including P. melaninogenica, P. intermedia, P. nigrescens, and the ruminal species P. ruminicola. Two oral species, P. zoogleoformans and P. heparinolytica, which had been recently placed in the genus Prevotella, did not fall within the prevotella cluster. These two species and six species of Bacteroides, including the type species B. fragilis, formed the second cluster, termed the bacteroides cluster. The third cluster, termed the porphyromonas cluster, was divided into two subclusters. The first contained Porphyromonas gingivalis, P. endodontalis, P. asaccharolytica, P. circumdentaria, P. salivosa, [Bacteroides] levii (the brackets around genus are used to indicate that the species does not belong to the genus by the sensu stricto definition), and [Bacteroides] macacae, and the second subcluster contained [Bacteroides] forsythus and [Bacteroides] distasonis. [Bacteroides] splanchnicus fell just outside the three major clusters but still belonged within the bacteroides subgroup. With few exceptions, the 16 S rRNA data were in overall agreement with previously proposed reclassifications of species of Bacteroides, Prevotella, and Porphyromonas. Suggestions are made to accommodate those species which do not fit previous reclassification schemes.

Bacteroides↗
PubMed1994

Chemotaxonomy of Bacteroides: a review.

The loose definition of Bacteroides, some species of which are important etiologic agents of oral diseases, has enabled isolates with only marginal similarities to be reposited in this genus. Many attempts have been made over the years to improve the taxonomy of this heterogeneous group of bacteria. The present article reviews major chemotaxonomic characters and techniques that have been used for this purpose: pigmentation, metabolites, whole-cell fatty acids, phospholipids, isoprenoid quinones, carbohydrates of lipopolysaccharide, whole-cell proteins, peptidoglycans, enzymes, pyrolysis mass spectrometry, DNA composition, restriction fragment length polymorphisms of DNA and ribosomal (r) RNA, homology of DNA and RNA, DNA-rRNA hybridization, and 16S and 5S rRNA oligonucleotide cataloging and sequencing. Despite improvements in their taxonomy, some bacteroides are still misclassified. Suggestions for further improvements in the taxonomy of bacteroides are made.

Bacteroides↗
PubMed1994

Circulating endothelin-1 levels in systemic sclerosis subsets--a marker of fibrosis or vascular dysfunction?

OBJECTIVE: To investigate the circulating levels of endothelin-1 (ET-1) in serum (sET-1) in patients with pulmonary disease [pulmonary fibrosis (PF) and pulmonary hypertension (PHT)], and renal involvement [hypertensive renal crisis (HRC)] in the 2 major subsets of systemic sclerosis (SSc) in order to determine the significance of sET-1 levels in relation to specific organ involvement or to the underlying pathogenic mechanisms of vascular damage and fibrosis. METHODS: In addition to the measurement of ET-1 in serum using a competitive radioimmunoassay, the circulating levels of angiotensin converting enzyme (ACE) and plasma von Willebrand factor (vWF) were measured as markers of endothelial damage in the various disease groups. RESULTS: Levels of sET-1 were significantly increased in 64 patients with diffuse systemic sclerosis (dSSc) and 17 patients with primary Raynaud's phenomenon (RP) compared with 22 healthy individuals. sET-1 levels were equally elevated in diffuse cutaneous disease (dcSSc) with only fibrotic dermal or lung pathology compared with patients with additional PHT or HRC crisis. These observations were in marked contrast to the sET-1 levels seen in patients with the limited cutaneous form of SSc (lcSSc) where only patients with lcSSc with hypertensive lung or renal disease had significantly higher levels of sET-1 than comparable lcSSc patients with only fibrotic dermal and lung disease. sET-1 levels were additionally found to correlate with plasma vWF, skin fibrosis (skin score) and duration of disease in patients with SSc. CONCLUSION: The presence of significantly raised sET-1 levels in patients with dcSSc with widespread fibrosis and patients with lcSSc with hypertensive disease and the relationship seen between sET-1 levels and markers of fibrosis and vascular damage suggest that ET-1 may be important in the pathogenesis of both the fibrotic and vascular manifestations in SSc.

Biomarkers↗
PubMed1993

Multi-level regulation of lysosomal gene expression in lymphocytes.

The expression of the gene coding for the lysosomal enzyme, beta-glucuronidase (Gus), was examined in functionally distinct T, B and plasma cell lines. Each of the different groups of cells had different intracellular levels of active Gus enzyme and numbers of Gus mRNA copies per cell. Analysis of the molecular forms of Gus mRNA and protein by Northern and Western blotting revealed that the different types of cells all produced a single mature 2.7 kb transcript and a 73 kDa polypeptide. However, the utilisation of the Gus mRNA to produce the Gus antigen, and the subsequent posttranslational processing of the polypeptide to generate the mature, enzymically active Gus, were found to be cell type-specific. Control of the functional expression of the Gus gene is thus exerted at both the transcriptional and translational levels, and appears to differ between different types of lymphocyte.

Animals↗