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P Toivanen

Publications and source records attributed to P Toivanen.

At least 55 records · Page 3Linked to original sources
PubMed1998

Persistence of Yersinia antigens in peripheral blood cells from patients with Yersinia enterocolitica O:3 infection with or without reactive arthritis.

OBJECTIVE: To assess the persistence of bacterial antigens in peripheral blood cells from patients with Yersinia enterocolitica O:3-triggered reactive arthritis (ReA). METHODS: Peripheral blood samples were obtained from 20 patients with Y. enterocolitica O:3 infection (11 with ReA and 9 without). These samples were studied by immunochemical techniques for the presence of Yersinia antigens at the beginning of infection and up to 4 years thereafter. Synovial fluid samples from 6 of the 11 ReA patients were also studied. RESULTS: The Yersinia antigens lipopolysaccharide and heat-shock protein (HSP) were detected in peripheral blood mononuclear cells and polymorphonuclear phagocytes from all patients studied at the early phase of the disease. They were also found in the synovial fluid cells of patients with Yersinia-triggered ReA. At 4 years after the onset of infection, these bacterial antigens were still detected in the peripheral blood cells of most of the ReA patients studied. CONCLUSION: This study has, for the first time, directly demonstrated that bacterial antigens persist for a long time in patients who develop ReA after Y. enterocolitica O:3 infection. The finding of bacterial HSP in synovial fluid cells could provide a link to the pathogenesis of ReA, since T cell responses of synovial cells have been shown to be directed against that structure. A close similarity between the bacterial and host HSP might contribute to the development of the relatively common, chronic form of this complication.

Antibodies, Bacterial↗
PubMed1998

The use of a surface adhesion immunofluorescent (SAIF) method for the rapid detection of Yersinia enterocolitica serotype O:3 in meat.

This study examined the attachment kinetics of Yersinia enterocolitica serotype O:3 to determine the optimum conditions for its isolation from meat enrichment systems using a novel surface adhesion technique. Minced beef was inoculated with Y. enterocolitica at an initial level of 10 cfu g-1 and incubated at 25 degrees C in an enrichment broth. Yersinia was recovered from enriched samples on polycarbonate membranes by surface adhesion and enumerated using immunofluorescence microscopy. The surface adhesion immunofluorescence technique (SAIF) had a minimum detection limit of approximately 4.0-4.5 log10 cfu ml-1 and provided good correlation between the estimation of the numbers of Yersinia in the enrichment broth derived from plate counts on Yersinia Selective agar (CIN) and those determined by SAIF (r2 = 0.94; rsd = +/- 0.21). A derived regression equation of the SAIF count vs plate counts was used to predict Y. enterocolitica numbers in spiked meat samples stored at 0 degree C for up to 20 d. The numbers as predicted by the SAIF method showed good correlation with counts derived by plating techniques (r2 = 0.78; rsd = +/- 0.42). The application of the SAIF technique for the rapid detection of Y. enterocolitica serotype O:3 from meat is discussed.

Animals↗
PubMed1998

Interleukin-10 inhibits the capacity of synovial macrophages to function as antigen-presenting cells.

OBJECTIVE: We have investigated the effects of interleukin (IL)-10, IL-4 + granulocyte/macrophage colony-stimulating factor (GM-CSF) and tumour necrosis factor alpha (TNF-alpha) on the phenotype and antigen-presenting capacity of synovial fluid (SF) macrophages from patients with rheumatoid arthritis. METHODS: The effects of IL-4, IL-10, GM-CSF and TNF-alpha on the expression of surface antigens on SF macrophages were studied using flow cytometry. The effects of these cytokines on the capacity of SF macrophages to activate T cells was investigated using the allogeneic mixed lymphocyte reaction (MLR). RESULTS: IL-10 reduced the expression of CD40, CD86 and HLA-DR, and increased the expression of CD14, on SF macrophages. IL-10 had no effect on the expression of CD80. Importantly, these effects of IL-10 on the phenotype of SF macrophages appear to have functional consequences, because cells incubated with IL-10 had a significantly reduced capacity to activate T cells in MLR. The effects of IL-4, GM-CSF and TNF-alpha were generally opposite to those observed in response to IL-10. IL-4 + GM-CSF, a combination of cytokines known to induce differentiation of dendritic cells, increased the expression of CD40, CD80 and CD86, and decreased the expression of CD14 on SF macrophages. Accordingly, IL-4 + GM-CSF increased the capacity of SF macrophages to activate T cells in MLR. IL-10 inhibited the effects of IL-4 + GM-CSF on SF macrophages. CONCLUSIONS: IL-10 inhibits the antigen-presenting capacity of SF macrophages, which further emphasizes the anti-inflammatory potential of IL-10 in RA. Importantly, IL-10 is able to downregulate the APC function of SF macrophages even when they are efficiently activated.

Adult↗
PubMed1997

Increased expression of signaling lymphocytic activation molecule in patients with rheumatoid arthritis and its role in the regulation of cytokine production in rheumatoid synovium.

In the present study the expression and function of signaling lymphocytic activation molecule (SLAM) in lymphocytes from patients with rheumatoid arthritis (RA) were investigated. The expression levels of SLAM were significantly up-regulated on synovial fluid and synovial tissue T cells from patients with RA compared with peripheral blood T cells from the same patients or from healthy volunteers. In addition, the expression of SLAM on peripheral blood B cells from patients with RA was elevated compared with that in healthy volunteers. SLAM+ T cells in synovial fluid coexpressed CD45RO and demonstrated decreased expression of CD27, indicative of a primed phenotype. In addition, the activation state of SLAM+ T cells was enhanced, as judged by increased expression of CD25, CD28, CD69, and CD95 on these cells. Interestingly, SLAM expression on activated CD4+ and CD8+ T cells from both patients and healthy individuals could be down-regulated by IL-10, which has been previously shown to function as an anti-inflammatory molecule in rheumatoid synovium. Furthermore, anti-SLAM mAbs increased the production of IL-10, IFN-gamma, and TNF-alpha by in vitro activated synovial fluid mononuclear cells, supporting the idea that signaling through SLAM may play a role in the regulation of synovial inflammation in patients with RA. Given the fact that SLAM was recently shown to be a high affinity self ligand, our data suggest that synovial T cells may stimulate their own cytokine production through homophilic SLAM-SLAM interactions.

Adult↗
PubMed1997

H-ras oncogene point mutations in arthritic synovium.

OBJECTIVE: To examine mutational activation of ras proto-oncogenes in synovial tissue from patients with rheumatoid arthritis (RA) compared with synovial specimens from patients with osteoarthritis (OA) or other arthropathies. Synovial samples from cadavers, without any signs of joint disease, were used as control material. METHODS: Using a combination of polymerase chain reaction (PCR) and automated sequencing of the amplified PCR product, regions around codons 12, 13, and 61 of the H-, K-, and N-ras proto-oncogenes were analyzed. Confirmation of mutations was based on restriction fragment length polymorphism analysis and/or oligonucleotide hybridization. RESULTS: Four (6%) of 72 patients with RA, 2 (13%) of 16 with OA, and 1 (8%) of 12 with other arthropathies harbored mutant H-ras proto-oncogenes, and were heterozygous at codon 13 for the GGT-->GAT (Gly-->Asp) change. An unexpected mutation was found in the H-ras gene, in which a heterozygous GTG-->ATG (Val-->Met) mutation was observed over codon 14. The incidence for this mutation was 39% (28 of 72) in RA patients, 94% (15 of 16) in OA patients, and 42% (5 of 12) in patients with other arthropathies. All samples carrying the codon 13 mutation of H-ras were also codon 14-mutated, i.e., double mutations existed. Identical point mutations were also detected in a few synovial specimens obtained from cadavers (n = 8), including a single case of double mutation. All specimens showed normal K- and N-ras loci. CONCLUSION: Activation of proto-oncogene H-ras by point mutation in codons 13 and 14 occurred in the synovial tissue of patients with RA, OA, or other arthropathies, as well as, to some extent, in the control synovia, indicating that the phenomenon is not specific for RA. In codon 14, incidence of the H-ras point mutation was highest in OA tissue. The possible significance of this codon 14-mutated H-ras gene needs to be clarified.

Adult↗
PubMed1997

A novel peripheral CD4+ CD8+ T cell population: inheritance of CD8alpha expression on CD4+ T cells.

In this study we show the inheritance of a CD4+ CD8+ peripheral Tcell population in the H.B15 chicken strain. A large proportion of alphabeta T cells in peripheral blood (20-40%), spleen (10-20%) and intestinal epithelium (5-10%) coexpress CD4 and CD8alpha, but not CD8beta. CD4+ CD8alpha alpha cells are functionally normal T cells, since they proliferate in response to mitogens and signals delivered via the alphabeta T cell receptor as well as via the CD28 co-receptor. These cells induce in vivo a graft versus host-reaction, providing further evidence for their function as CD4+ T cells. The CD4+ CD8alpha alpha T cell population was found in 75% of the first progeny and in 100% of further progenies, demonstrating that coexpression of CD4 and CD8 on peripheral T cells is an inherited phenomenon. In addition, cross-breeding data suggest a dominant Mendelian form of inheritance. The hereditary expression of CD8alpha on peripheral CD4+ T cells in chicken provides a unique model in which to study the regulation of CD4 and CD8 expression.

Animals↗
PubMed1997

Muramic acid in human peripheral blood leucocytes in different age groups.

Presence of muramic acid (as a marker for bacterial cell wall peptidoglycan) was analysed by gas chromatography and mass spectrometry in the peripheral blood leucocytes of subjects from a range of ages (9-80 years) and groups (healthy individuals, patients with rheumatoid arthritis, osteoarthrosis, essential hypertension or multiple sclerosis). Sixty per cent of the sample from the youngest subjects contained detectable muramic acid. The percentage of people with circulating leucocytes containing muramic acid decreased gradually with age, being less than 5% in all groups over 40 years. No clear correlation between the presence of muramic acid and the disease was observed.

Adolescent↗
PubMed1997

Molecular and chemical characterization of the lipopolysaccharide O-antigen and its role in the virulence of Yersinia enterocolitica serotype O:8.

The Y. enterocolitica O:8(YeO8) O-antigen repeat units consist of five sugar residues: N-acetyl-D-galactosamine (GalNAc), D-galactose (Gal), D-mannose (Man), L-fucose (Fuc), and 6-deoxy-D-gulose (6d-Gul). The nucleotide sequence of the O-antigen gene cluster of the YeO8 strain 8081-c was determined. Altogether, 18 open reading frames (ORFs) were identified and shown to be essential for O-antigen biosynthesis. We previously characterized the 3'-end of the O-antigen gene cluster and identified four genes: two for GDP-Man biosynthesis, one for UDP-Gal biosynthesis, and one for O-antigen polymerase. Based on sequence similarity, Tn5-insertion phenotypes and chemical analysis, the 14 new genes were assigned the following functions: four genes are involved in the biosynthesis of CDP-6d-Gul and two in GDP-Fuc biosynthesis. Five gene products were assigned sugar transferase functions and one gene product was similar to Wzx, the O-antigen flippase. Two genes remained unassigned. By genetic complementation we also showed that YeO8 O-antigen biosynthesis was dependent on N-acetyl-glucosaminyl:undecaprenylphosphate transferase (GlcNAc transferase), the WecA (formerly known as Rfe) protein. Data obtained from chemical-composition analysis suggest that in addition to being GlcNAc transferase, WecA may also function as a GalNAc transferase. Using a restriction-deficient derivative of Y. enterocolitica O:8 strain 8081, a rough mutant, designated 8081-R2, was isolated. 8081-R2 was complemented in trans with a cloned O-antigen gene cluster restoring surface O-antigen expression. The virulence of the wild-type strain and that of the complemented strain were significantly higher (approx. 100-fold) than that of the rough mutant in an orally infected mouse model, showing that YeO8 O-antigen is a virulence factor.

Animals↗
PubMed1997

Application of an enzyme immunoassay to monitor bacterial binding and to measure inhibition of binding to different types of solid surfaces.

We describe the application of an enzyme immunoassay (EIA) for detecting bacteria bound to a solid surface. Different Yersinia enterocolitica and Escherichia coli strains, expressing the YadA protein, type 1 or type P fimbriae were used as models for this study. The assay was used to detect bacteria bound to fixed tissues or to glass slides coated with extracellular matrix molecules (collagen, laminin or fibronectin). E. coli specific antiserum (B357, Dakopatts, Glostrup, Denmark) and peroxidase conjugated antiserum (P217) were used to detect all E. coli strains used in the study. The bacterial binding could be monitored with a linear detection range between 10(5) and 10(8) bacteria. Most importantly, dose dependent inhibition of bacterial binding by soluble extracellular matrix molecules could be measured.

Animals↗
PubMed1997

Faecal microbial flora and disease activity in rheumatoid arthritis during a vegan diet.

To clarify the role of the faecal flora in the diet-induced decrease of rheumatoid arthritis (RA) activity, 43 RA patients were randomized into two groups: the test group to receive living food, a form of uncooked vegan diet rich in lactobacilli, and the control group to continue their ordinary omnivorous diets. Based on clinical assessments before, during and after the intervention period, a disease improvement index was constructed for each patient. According to the index, patients were assigned either to a group with a high improvement index (HI) or to a group with a low improvement index (LO). Stool samples collected from each patient before the intervention and at 1 month were analysed by direct stool sample gas-liquid chromatography of bacterial cellular fatty acids. This method has proved to be a simple and sensitive way to detect changes and differences in the faecal microbial flora between individual stool samples or groups of them. A significant, diet-induced change in the faecal flora (P = 0.001) was observed in the test group, but not in the control group. Further, in the test group, a significant (P = 0.001) difference was detected between the HI and LO categories at 1 month, but not in the pre-test samples. We conclude that a vegan diet changes the faecal microbial flora in RA patients, and changes in the faecal flora are associated with improvement in RA activity.

Arthritis, Rheumatoid↗
PubMed1997

Experimental Yersinia-triggered reactive arthritis: effect of a 3-week course of ciprofloxacin.

Lewis rats were injected i.v. with live Yersinia enterocolitica, resulting in 1-2 weeks in an arthritis greatly resembling human reactive arthritis. Starting on day 3, 5, 10 or 13 after the bacterial inoculation, the rats were treated for 3 weeks with 20 mg/kg/day of ciprofloxacin. The development of arthritis was completely prevented if the antibiotic treatment was started on day 3. In a group of rats treated with ciprofloxacin from day 5 onwards, 2/14 rats already showed mild arthritis at the time when the treatment was started. Antibiotic treatment cured the arthritis of these rats as well as that of one additional individual in this group which developed arthritis. No later exacerbations occurred. If the antibiotic treatment was started on day 10 or 13, i.e. at the time of well-developed arthritis, no effect on arthritis was observed; rather, increased faecal excretion of Yersinia occurred following the antibiotic treatment. We conclude that experimental Yersinia reactive arthritis can be cured by antibiotics introduced at an early phase of arthritic development. Regarding acute human enterogenic arthritis, the decision on antibiotic treatment is not a straightforward matter. Our experimental results indicate that the earlier the treatment is started, the better the result, whereas late treatments seem to favour bacterial persistence.

Animals↗
PubMed1997

Ligase chain reaction in detection of Chlamydia DNA in synovial fluid cells.

Synovial fluid cells from 12 patients with reactive arthritis (ReA) triggered by Chlamydia trachomatis were studied for the presence of Chlamydia DNA using the ligase chain reaction (LCR) LCx (Abbott) and the polymerase chain reaction (PCR) Amplicor (Roche). In addition, peripheral blood leucocytes from 11 of these patients were analysed by LCR. As controls, seven patients with newly diagnosed rheumatoid arthritis (RA) were included. Chlamydia trachomatis DNA was detectable by LCR in samples of synovial fluid cells from 4/12 patients with C. trachomatis-triggered ReA, and in none by PCR. Chlamydia trachomatis DNA was not detectable in the synovial fluid cells of the seven RA patients by either method, neither was C. trachomatis DNA detectable in the peripheral blood leucocytes of the ReA patients (0/11) or controls (0/6) by LCR. The LCR technique may be useful in the demonstration of Chlamydia DNA in synovial fluid cells.

Adolescent↗
PubMed1997

Reactive arthritis.

The complex interactions between the triggering microbe and the defense mechanisms of the host in reactive arthritis have been studied in several laboratories around the world, and interesting observations have been made. Research has also focused on the mediators in the inflammatory process in joints, and these results are helping to slowly build a comprehensive picture about the pathogenetic process in reactive arthritis. For the practicing clinician, some important new findings have emerged. It is known that asymptomatic urogenital infections are quite common as a trigger of reactive arthritis. More aggressive treatment, including disease-modifying drugs as used in the therapy of rheumatoid arthritis, is becoming accepted. The value of antibiotic treatment is being studied, but final conclusions will not be made for perhaps a few years.

Animals↗
PubMed1997

Interstitial chemotherapy with carmustine-loaded polymers for high-grade gliomas: a randomized double-blind study.

OBJECTIVE: To find out the effect of carmustine (bischloroethyl-nitrosourea) combined with a biodegradable polymer in the treatment of malignant (Grades III and IV) gliomas, applied locally, at the time of the primary operation. METHODS: Prospective, randomized double-blind study of an active treatment group versus a placebo group. Conducted at the Departments of Neurosurgery of the University Hospitals of Helsinki, Tampere, and Turku in Finland and Trondheim in Norway. The study consisted of 32 patients (16 in each treatment group) enrolled between March 23, 1992, and March 19, 1993. The study was planned to include 100 patients but had to be terminated prematurely, because the drug that was being used had become unobtainable. The main outcome measures included the survival times of patients after the operations and the application of an active drug or placebo. RESULTS: The median time from surgery to death was 58.1 weeks for the active treatment group versus 39.9 weeks for the placebo group (P = 0.012). For 27 patients with Grade IV tumors, the corresponding times were 39.9 weeks for the placebo group and 53.3 weeks for the active treatment group (P = 0.008). At the end of the study, six patients were still alive, five of whom belonged to the active treatment group. CONCLUSION: Carmustine applied locally in a biodegradable polymer at the time of primary operation, seems to have a favorable effect on the life span of patients with high-grade gliomas.

Adult↗
PubMed1997

Detection of rubella, mumps, and measles virus genomic RNA in cells from synovial fluid and peripheral blood in early rheumatoid arthritis.

OBJECTIVE: To determine, by studying patients with early rheumatoid arthritis (RA), whether rubella virus (rubella), mumps virus (mumps), or measles virus (measles) plays a role in the pathogenesis of RA. METHODS: Polymerase chain reaction combined with reverse transcription was used to detect viral RNA in peripheral blood mononuclear cells (PBMC) or synovial fluid (SF) cells. The patients with RA had newly diagnosed disease (duration < or = 1 year). The controls were patients with other arthropathies. RESULTS: Rubella genomic RNA was not detected in SF cells from patients with early RA or from controls, or in PBMC from patients with RA. It was found in PBMC of one of 46 patients with other arthropathies. Mumps or measles genomic RNA was detected in PBMC samples from 1.8% (1/54) and 9.3% (5/54) of RA, respectively, and from 4.3% (2/46) and 6.5% (3/46) of control patients. The SF cell samples harbored mumps or measles RNA in 4.8% (2/42) and 7.1% (3/42) of patients with RA, respectively; the corresponding value was 6.5% (2/31) for control patients, for both mumps and measles. CONCLUSION: Our findings suggest rubella, mumps, or measles do not play a role in the etiopathogenesis of RA.

Adult↗
PubMed1996

Interleukin-10 functions as an antiinflammatory cytokine in rheumatoid synovium.

OBJECTIVE: Interleukin-10 (IL-10) is an antiinflammatory cytokine that has been shown to play a role in rheumatoid arthritis (RA). We therefore investigated the effects of IL-10 on the function and phenotype of synovial fluid mononuclear cells (SFMC) derived from patients with RA. In addition, we studied the production of IL-10 in rheumatoid joints, and the role of endogenous IL-10 in the regulation of SFMC function. METHODS: The presence of IL-10 in rheumatoid joints was studied using IL-10-specific enzyme-linked immunosorbent assay (ELISA) and reverse transcriptase- polymerase chain reaction (RT-PCR) techniques. The effects of recombinant human IL-10 or neutralizing anti-IL-10 monoclonal antibodies (MAbs) on both cytokine production and phenotype of SFMC were evaluated using cytokine-specific ELISAs and flow cytometry. The effect of IL-10 on proliferation of SFMC was determined by incorporation of tritiated thymidine. RESULTS: IL-10 was detected by ELISA in 22 of 23 SF samples, and was spontaneously produced by cultured SFMC. IL-10 messenger RNA was detectable in all 8 SFMC samples, as determined by RT-PCR. Neutralization of endogenously produced IL-10 by anti- IL-10 MAbs resulted in increased production of IL-1 beta, tumor necrosis factor alpha (TNF alpha), and granulocyte- macrophage colony-stimulating factor (GM-CSF) by SFMC, and in enhanced proliferation of SFMC. In particular, the production of TNFalpha was dramatically increased by anti-IL-10 MAbs. Moreover, the expression of HLA-DR molecules by SF macrophages was increased, and the expression of CD16 was decreased by anti-IL-10 MAbs. In contrast, addition of recombinant IL-10 significantly decreased the production of IL-1 beta, TNF alpha, and GM-CSF by SFMC, and decreased spontaneous and IL-2-induced proliferation of SFMC. Finally, IL-10 decreased HLA-DR expression and increased the expression of the Fc gamma receptors, CD16 and CD64, by SF macrophages. CONCLUSION: These data indicate that endogenously produced IL-10 functions as an immunoregulatory molecule in rheumatoid synovium. Importantly, exogenous IL-10 has potent antiinflammatory effects on SFMC, suggesting that IL-10 may be useful in the treatment of patients with RA.

Adult↗
PubMed1996

Antibiotic prophylaxis and treatment of reactive arthritis. Lessons from an animal model.

OBJECTIVE: To study the effect of antibiotic prophylaxis and treatment of reactive arthritis (ReA), using an experimental model. METHODS: Yersinia enterocolitica O:8, when injected intravenously into Lewis rats, causes a sterile arthritis closely resembling human ReA in 70% of the animals. Arthritis develops in 1-2 weeks; in some of the animals it remains chronic, and exacerbations occur. This model was applied to study the effect of a 7-day treatment with ciprofloxacin, using 2 different dosages (20 or 100 mg/kg/day) and 4 different schedules for initiation of treatment. The effects were evaluated by determining the daily arthritis score, the number of rats developing arthritis, and fecal excretion of Yersinia. In addition, weight gain was monitored. At autopsy (35 or 60 days after inoculation with bacteria), samples were obtained for determination of Yersinia-specific antibodies in the serum. At the same time, samples were collected from mesenteric lymph nodes, lung, spleen, and liver for bacterial cultures, and from the ankle joints for histologic evaluation. In a separate experiment, ciprofloxacin concentrations in samples from serum and mesenteric lymph nodes were analyzed by high performance liquid chromatography. RESULTS: A 7-day course with 100 mg/kg/day of ciprofloxacin, started on day 3 after bacterial inoculation, completely prevented the development of ReA and eliminated Yersinia during the 60-day experiment. If a dosage of 20 mg/kg/day was used, development of acute arthritis was prevented, but some of the animals had positive fecal cultures at the end of experiment. If antibiotic treatment was started on day 5, the preventive effect was still observed, but was less pronounced. If the treatment was started at the peak of the development of arthritis, no effect on arthritis was observed. CONCLUSION: These results indicate that if any effect of antibiotic treatment in Yersinia-triggered ReA is to be expected, the treatment must be started early and given in sufficient dosage. However, antibiotic treatment has no effect on fully developed arthritis.

Animals↗