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Toxoplasma Infection (toxoplasma + infection)
Selected AbstractsIn situ assays demonstrate that interferon-gamma suppresses infection-stimulated hepatic fibrin deposition by promoting fibrinolysisJOURNAL OF THROMBOSIS AND HAEMOSTASIS, Issue 7 2006I. K. MULLARKY Summary.,Background:,Inflammatory cytokines potently impact hemostatic pathways during infection, but the tissue-specific regulation of coagulation and fibrinolysis complicates studies of the underlying mechanisms. Methods and Results:,Here, we describe assays that quantitatively measuring prothrombinase (PTase), protein C-ase (PCase) and plasminogen activator (PA) activities in situ, thereby facilitating studies of tissue-specific hemostasis. Using these assays, we investigate the mechanisms regulating hepatic fibrin deposition during murine toxoplasmosis and the means by which interferon-gamma (IFN- ,) suppresses infection-stimulated fibrin deposition. We demonstrate that Toxoplasma infection upregulates hepatic PTase, PCase, and PA activity. Wild type and gene-targeted IFN- , -deficient mice exhibit similar levels of infection-stimulated PTase activity. By contrast, IFN- , -deficiency is associated with increased PCase activity and reduced PA activity during infection. Parallel analyses of hepatic gene expression reveal that IFN- , -deficiency is associated with increased expression of thrombomodulin (TM), a key component of the PCase, increased expression of thrombin-activatable fibrinolysis inhibitor (TAFI), a PC substrate, and reduced expression of urokinase PA (u-PA). Conclusions:,These findings suggest that IFN- , suppresses infection-stimulated hepatic fibrin deposition by suppressing TM-mediated activation of TAFI, thereby destabilizing fibrin deposits, and concomitantly increasing hepatic u-PA activity, thereby promoting fibrinolysis. We anticipate that further application of these in situ assays will improve our understanding of tissue-specific hemostasis, its regulation by cytokines, and its dysregulation during coagulopathy. [source] Low incidence of hypertensive disorders of pregnancy in women treated with spiramycin for toxoplasma infectionBRITISH JOURNAL OF CLINICAL PHARMACOLOGY, Issue 3 2006T. Todros Aims Toxoplasma infection in pregnancy is usually treated with long-term administration of the macrolide spiramycin to prevent fetal malformations. We had empirically observed that treated patients seldom developed pregnancy-induced hypertension (PIH), a common and severe disorder of pregnancy whose aetiology and pathogenesis are still debated. Some clinical and experimental data suggest that infection could play a role in its development. Methods To test this hypothesis, we studied a cohort of 417 pregnant women treated with spiramycin because of seroconversion for Toxoplasma gondii and 353 low-risk women who did not take any antibiotic during pregnancy. PIH was defined as blood pressure >140/90 mmHg on two or more occasions, occurring after 20 weeks of gestational age. Results Seventeen (5.2%) women in the control group developed PIH compared with two (0.5%) in the case group. The odds of developing the disease were significantly lower in the treated subjects (odds ratio =,0.092, 95% confidence interval 0.021, 0.399; P < 0.001). Conclusions Our results suggest that antibiotic treatment during pregnancy can reduce the incidence of PIH, thus opening new perspectives in its prevention and therapy. [source] Transepithelial migration of Toxoplasma gondii involves an interaction of intercellular adhesion molecule 1 (ICAM-1) with the parasite adhesin MIC2CELLULAR MICROBIOLOGY, Issue 4 2005Antonio Barragan Summary Toxoplasma gondii crosses non-permissive biological barriers such as the intestine, the blood,brain barrier and the placenta thereby gaining access to tissues where it most commonly causes severe pathology. Herein we show that in the process of migration Toxoplasma initially concentrates around intercellular junctions and probably uses a paracellular pathway to transmigrate across biological barriers. Parasite transmigration required viable and actively motile parasites. Interestingly, the integrity of host cell barriers was not altered during parasite transmigration. As intercellular adhesion molecule 1 (ICAM-1) is upregulated on cellular barriers during Toxoplasma infection, we investigated the role of this receptor in parasite transmigration. Soluble human ICAM-1 and ICAM-1 antibodies inhibited transmigration of parasites across cellular barriers implicating this receptor in the process of transmigration. Furthermore, human ICAM-1 immunoprecipitated the mature form of the parasite adhesin MIC2 present on the parasite surface, indicating that this interaction may contribute to cellular migration. These findings reveal that Toxoplasma exploits the natural cell trafficking pathways in the host to cross cellular barriers and disseminate to deep tissues. [source] Immunity and Toxoplasma retinochoroiditisCLINICAL & EXPERIMENTAL IMMUNOLOGY, Issue 3 2008G. R. Wallace Summary Toxoplasma infection accounts for up to 50% of all cases of posterior uveitis worldwide. In this review the control of Toxoplasma infection generally, and specific in the eye, by the immune system is discussed. [source] New and old risk-factors for Toxoplasma gondii infection: prospective cross-sectional study among military personnel in the Czech RepublicCLINICAL MICROBIOLOGY AND INFECTION, Issue 10 2007P. Kolbekova Abstract The aims of this study were to evaluate seroprevalence and the importance of various risk-factors for Toxoplasma infection in the Czech Republic. A prospective cross-sectional survey was conducted among military personnel in Prague. Consenting subjects (n = 3250) completed a questionnaire concerning demographics and risk-factors, and blood samples were taken to determine anti- Toxoplasma antibody titres according to complement fixation and ELISA IgG and IgM tests. The seroprevalence of toxoplasmosis was 23%. In multivariate analysis, independent predictors of Toxoplasma seropositivity were age (OR 1.03,/,year), consumption of raw meat (OR 1.35), owning a cat (OR 1.25), owning rabbits (OR 1.47), childhood residence in a town with a population of <10 000 inhabitants (OR 1.63) vs. location of the childhood residence in a town with population of >100 000 inhabitants, and blood group type A (OR 1.28), B (OR 1.33) or AB (OR 1.43) vs. O. These results suggested that horizontal toxoplasmosis transmission in the Czech Republic may occur through consumption of raw meat, contact with cat faeces and farming. [source] Prediction of congenital toxoplasmosis by polymerase chain reaction analysis of amniotic fluidBJOG : AN INTERNATIONAL JOURNAL OF OBSTETRICS & GYNAECOLOGY, Issue 5 2005L. Thalib Objective To determine the accuracy of polymerase chain reaction (PCR) analysis of amniotic fluid for fetal toxoplasmosis according to clinical predictors of outcome and study centre. Design Prospective cohort study. Setting Nine European centres. Population Women with suspected toxoplasma infection identified by prenatal screening. Methods Logistic regression was used to examine the effects of gestational age at maternal seroconversion, treatment and timing of amniocentesis, on PCR accuracy, and to calculate the post-test probability of congenital toxoplasmosis. Main outcome measures Infants had congenital toxoplasmosis if specific IgG persisted beyond 11.5 months. Uninfected infants had undetectable IgG in the absence of anti-toxoplasma treatment. Results Of 593 PCR results, 64 were positive (57 confirmed infected), and 529 were negative (23 confirmed infected). The likelihood ratio for a positive PCR result decreased significantly with trimester at seroconversion, but did not change significantly for a negative result. Weak associations were detected between sensitivity and, inversely, with specificity, and gestational age at maternal seroconversion. There was no significant association between sensitivity and centre, type or duration of treatment, or timing of amniocentesis. Specificity differed significantly between centres (P < 0.001). The change in pre- to post-test probability of infection was maximal for a positive PCR after first trimester seroconversion, affecting 1% of women tested, and a negative PCR after third trimester seroconversion, affecting half the women tested. Conclusions Prediction of the risk of congenital toxoplasmosis should combine estimates of test accuracy and maternal,fetal transmission, which take account of the gestational age at which the mother seroconverted. Local laboratory standards will affect the generalisability of these results. [source] Low incidence of hypertensive disorders of pregnancy in women treated with spiramycin for toxoplasma infectionBRITISH JOURNAL OF CLINICAL PHARMACOLOGY, Issue 3 2006T. Todros Aims Toxoplasma infection in pregnancy is usually treated with long-term administration of the macrolide spiramycin to prevent fetal malformations. We had empirically observed that treated patients seldom developed pregnancy-induced hypertension (PIH), a common and severe disorder of pregnancy whose aetiology and pathogenesis are still debated. Some clinical and experimental data suggest that infection could play a role in its development. Methods To test this hypothesis, we studied a cohort of 417 pregnant women treated with spiramycin because of seroconversion for Toxoplasma gondii and 353 low-risk women who did not take any antibiotic during pregnancy. PIH was defined as blood pressure >140/90 mmHg on two or more occasions, occurring after 20 weeks of gestational age. Results Seventeen (5.2%) women in the control group developed PIH compared with two (0.5%) in the case group. The odds of developing the disease were significantly lower in the treated subjects (odds ratio =,0.092, 95% confidence interval 0.021, 0.399; P < 0.001). Conclusions Our results suggest that antibiotic treatment during pregnancy can reduce the incidence of PIH, thus opening new perspectives in its prevention and therapy. [source] | ||||||||||