Human isolates of Yersinia enterocolitica serotypes 0:3 (biotype 4) and 0:9 (biotype 3) harbored plasmids sized approximately 47 and 44 megadaltons, respectively. No such plasmids were found in "apathogenic" strains of Y. enterocolitica belonging to biotype 1. There was a positive correlation among the presence of plasmid, autoagglutination, and adherence to and toxicity for HEp-2 cell cultures; all of these properties were lost by culturing at 37°C in the absence of calcium. Strains of Y. enterocolitica 0:3 and 0:9 cured of the plasmids showed increased invasiveness in the HEp-2 cell culture model, but no invasiveness in guinea pig eye. It is suggested that the plasmids of Y. enterocolitica primarily determine epithelial cell adherence, but may also be associated with other pathogenic properties. Zink et al. recently demonstrated that strains of Yersinia enterocolitica 0:8 which evoke a positive Ser6ny test in guinea pig eye harbor a plasmid of about 41 megadaltons (Mdal) in size (27). Similar plasmids have also been described in virulent strains of Y. pseudotuberculosis (8) and Y. pestis (6). Therefore these plasmids ap

BackgroundPeriodontal disease associates with systemic diseases but corresponding links regarding apical periodontitis (AP) are not so clear. Hence our aim was to study association between AP and the prevalence of systemic diseases in a study population from Sweden.MethodsThe subjects were 150 patients from a randomly selected epidemiological sample of 1676 individuals. 120 accepted to participate and their basic and clinical examination data were available for these secondary analyses where dental radiographs were used to record signs for endodontic treatments and AP. Periapical Index and modified Total Dental Index scores were calculated from the x-rays to classify the severity of AP and dental infection burden, respectively. Demographic and hospital record data were collected from the Swedish National Statistics Center. T-test, chi-square and univariate analysis of covariance (ANCOVA) and regressions analyses were used for statistics.ResultsOf the 120 patients 41% had AP and 61% had received endodontic treatments of which 52% were radiographically unsatisfactory. AP patients were older and half of them were smokers. AP and periodontitis often appeared in the same patient (32.5%). From all hospital diagnoses, cardiovascular diseases (CVD) were most common, showing 20.4% prevalence in AP patients. Regression analyses, controlled for age, gender, income, smoking and periodontitis, showed AP to associate with CVD with odds ratio 3.83 (95% confidence interval 1.18–12.40; p = 0.025).ConclusionsThe results confirmed our hypothesis by showing that AP statistically associated with cardiovascular diseases. The finding that subjects with AP also often had periodontitis indicates an increased oral inflammatory burden.

An enzyme-linked immunosorbent assay (ELISA) with bacterial sonicate (S) as antigen developed for determining the presence of IgM, IgA, and IgG antibodies to Francisella tularensis was compared with the bacterial agglutination (BA) test and a corresponding ELISA using lipopolysaccharide (LPS) antigen. Of the organisms tested, F tularensis was the only one to cause significant inhibition, indicating the specificity of the S-ELISA. BA test titers correlated significantly with antibody levels in all three immunoglobulin classes and most closely with IgM antibodies (r = 0.83). With some minor exceptions, the S-ELISA and the LPS-ELISA gave identical results, and the correlations between the tests were very close (r = 0.94-0.99). The S-ELISA confirmed the tularemia diagnosis with the first serum specimens from 43% of patients with tularemia vs 17% of the BA test. In addition, no seroconversion was observed by the BA test in 4% of the patients, although large increases were observed in S-ELISA titers.

A latex agglutination test (LX) using antisera prepared against Nebraska calf diarrhea virus (NCDV) is described for the detection of rotavirus in stool of children with acute gastroenteritis. The test was compared with electron microscopy (EM) and radioimmunoassay (RIA) with 100 stools positive or negative for rotavirus. Out of 53 stools positive in RIA or EM, 49 were positive in LX and 4 were negative. Two specimens negative in EM and RIA were falsely positive in LX. The method was also tested in two clinical series with 115 stools from 101 children. Altogether 67/115 stools were positive in RIA, and 62/115 in LX. Out of 7 stools with contradictory results, 6 were negative in LX but positive in RIA, and 1 was positive in LX but negative in RIA. The results indicate that the LX is suitable for rapid screening of rotavirus gastroenteritis in clinical practice.

We studied the relative number of lymphocyte subsets in the cerebrospinal fluid (CSF) of patients with active multiple sclerosis. The cells were double-labeled with monoclonal antibodies and were studied using a fluorescence-activated cell analyzer. The number of Leu2+Leu15+ cells and Leu3+Leu18+ cells was markedly reduced in the CSF but not in the peripheral blood of the patients. The number of Leu3+Leu18+ cells was reduced also in the CSF of control patients (patients with other inflammatory or infectious neurological diseases).

Two-day-old chick embryonic bodies were transplanted onto the area vasculosa of age-matched histocompatible blastoderms, resulting in the development of yolk sac-embryo chimaeras. Eighteen of these succeeded in hatching and became adults. Differences in the sex chromosomes and in IgG allotype between the embryo and the yolk sac were used to study the contribution of these two components to the lymphoid cell development. At 5-7 weeks of age the chimaeras proved to be completely normal in the IgM and IgG antibody production against human gamma globulin and Brucella abortus and in the lymphocyte responses to phytohaemagglutinin and concanavalin A. For the sex chromosome analyses bursa cells and specifically stimulated B and T lymphocytes were used. The latter was achieved by stimulating thymus, spleen, and bone marrow cells in vitro with anti-Ig and Con A. Only four out of 1498 mitoses analysed belonged to the sex opposite to that of the bird. Among the chimaeras eleven were marked through IgG allotypes. At the age of 3-20 weeks all eleven chimaeras showed serum IgG of the embryo allotype and none of the yolk sac type. These results, based on the use of two different markers, indicate that lymphoid stem cells in the chicken are originally derived from an intraembryonic source and not from the yolk sac.

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