Search PubMed⌕ Search

Biomedical subjects

I Villena

Publications and source records attributed to I Villena.

29 records · Page 2Linked to original sources
PubMed1998

Quantitative immunolocalization of a P29 protein (GRA7), a new antigen of toxoplasma gondii.

Ultrastructural localization of a P29 protein of Toxoplasma gondii was examined on thin sections by an immunogold technique using a P29 antigen-specific monoclonal antibody (5-241-178). Immunolocalization of the P29 protein in extracellular tachyzoites demonstrated that this antigen was present in the dense granules. Thus, we have identified this P29 antigen as the seventh protein (GRA7) to be localized to the dense granules of T. gondii. P29 immunolocalization in intracellular tachyzoites demonstrated association of this antigen with the parasite membrane complex, tubular elements of the intravacuolar network, and with the parasitophorous vacuolar membrane. Our immunolabeling data suggest trafficking of the P29 (GRA7) antigen from the dense granule via the intravacuolar network to the parasitophorous vacuolar membrane on invasion of the tachyzoite into the host cell. (J Histochem Cytochem 46:1411-1421, 1998)

Animals↗
PubMed1998

Prenatal diagnosis of congenital toxoplasmosis transmitted by an immunocompetent woman infected before conception. Reims Toxoplasmosis Group.

We report a rare case of congenital toxoplasmosis transmitted by an immunocompetent woman infected before conception. Active toxoplasmosis was suspected due to persistent lymphadenitis with specific IgM, IgA, IgE antibodies. Prenatal diagnosis based on amniocentesis and fetal blood sampling at 24 weeks' amenorrhoea was positive on amniotic fluid, and fetal infection was confirmed after termination. In our opinion such cases need the same monitoring as when seroconversion occurs during the first trimester. A pregnancy-free interval of six to nine months is recommended after proven patent toxoplasmosis seroconversion.

Adult↗
PubMed1997

Accelerated detection of DNA on membranes by automated enzyme-linked immunofiltration assay.

Methods used to detect DNA after transfer to nitro-cellulose or nylon membranes are all based on slow incubation with agitation. We describe an application of the ELIFA technique (enzyme-linked immunofiltration assay) for rapid detection of DNA immobilized on a membrane by active filtration of the reagents across the membrane. The different steps (saturation, hybridization to a nonisotopically labeled probe, washing, and immunoenzymatic revelation) are automated and controlled by a microcomputer that determines the direction of flow and flow rates of the solutions through the membrane. We applied this method to the detection of Toxoplasma gondii DNA in 108 samples of amniotic fluid during antenatal tests for toxoplasmosis and compared the results with those obtained by the conventional method. In addition to a major time saving (2 h against almost 15 h), automation improves reproducibility and avoids manipulation of the membranes between the different steps, while keeping the same sensitivity and specificity as the standard method.

Amniotic Fluid↗
PubMed1997

Prenatal diagnosis of congenital toxoplasmosis in 261 pregnancies.

Two hundred and sixty-one pregnant women underwent prenatal screening by cordocentesis and/or amniocentesis between 1987 and 1994. The following tests were used: (i) detection of anti-Toxoplasma gondii IgM, IgA, and IgE antibodies by immunocapture and the comparative immunological profile method based on enzyme-linked immunofiltration assay of fetal blood and (ii) direct detection of the parasite in cell culture and by mouse inoculation with fetal blood (FB) and/or amniotic fluid (AF). Of the 31 cases of congenital toxoplasmosis, 24 (77 per cent) were detected prenatally. Overall, the FB and AF inoculation methods were the most effective (50 per cent sensitivity with FB inoculation to mice and/or cell culture and 74 per cent with AF). However, antibody detection in FB was the only positive test in three cases. Of 18 surviving children diagnosed prenatally, only one developed chorioretinitis (9 months of age). Seven newborns (23 per cent) with negative prenatal tests were diagnosed by postnatal laboratory monitoring, but none of these children developed clinical toxoplasmosis. There may have been more false negatives, as only 48 per cent of unaffected children were followed up for at least 12 months. All the tests had a specificity of 100 per cent. Fetal blood sampling has considerable value but also carries some risks and is currently being abandoned in favour of amniocentesis alone with gene amplification and mouse inoculation.

Amniocentesis↗
PubMed1997

[Screening for congenital toxoplasmosis: pregnancy outcome after prenatal diagnosis in 211 cases].

OBJECTIVE: To emphasize the importance of follow-up after birth of infants with an antenatal diagnosis of congenital toxoplasmosis. METHODS: Retrospective study from July 1987 through January 31 1995 on 211 women (214 fetuses) who had undergone ovular biopsy for toxoplasmosis seroconversion during pregnancy. RESULTS: Antenatal diagnosis was positive in 13 patients (6.2%). Four pregnancies were terminated during the second trimester. Delivery was triggered at 37 weeks gestation in one woman and in 8 others pregnancy was continued with Fansidar. All infants were born live with infraclinic disease. Two fetal deaths related to biopsy technique occurred (0.95%) and one pregnancy was terminated before the results had been obtained. Only 21.3% of the patients were delivered in our unit. A total of 197 infants were delivered with a negative antenatal diagnosis: 93 were healthy, 5 had congenital toxoplasmosis, 1 died at 3 months and 98 had no or incomplete follow-up. CONCLUSION: Incomplete post-natal follow-up is in contradiction with the excellent performance of antenatal diagnosis of congenital toxoplasmosis. Greater care is needed, especially since now only an amniocentisis is required to detect the parasite genome with polymerase chain reaction.

Adolescent↗
PubMed1996

Antenatal diagnosis of congenital toxoplasmosis: evaluation of the biological parameters in a cohort of 286 patients.

OBJECTIVE: To evaluate the biological parameters obtained by cordocentesis and amniocentesis in the antenatal diagnosis of congenital toxoplasmosis. DESIGN: Nine-year retrospective study. SETTING: Parasitology Laboratory, Department of Obstetrics and Gynaecology and Department of Paediatrics, Centre Hospitalo-Universitaire, Montpellier, France. PARTICIPANTS: Two hundred and eighty-six pregnant women infected with toxoplasmosis between 7 and 34 weeks of gestation. METHODS: Detection of abnormalities by ultrasound examination. Detection in fetal blood of Toxoplasma, of specific IgM and IgA and of nonspecific biological markers. Detection in amniotic fluid of Toxoplasma. RESULTS: Out of 286 antenatal diagnoses, 211 were negative (1st group), 40 were positive (2nd group) and led to 8 medical abortions, and 35 were uncertain (3rd group). In the 1st and 3rd groups respectively, 7 (3.3%) and 5 (14.3%) cases of congenital toxoplasmosis were observed. Overall, 52 cases of congenital toxoplasmosis were detected: 12 were clinically apparent, 36 subclinical (of which 12 were in groups 1 and 3) and 4 were lost to follow up. CONCLUSION: There is substantial importance in making the diagnosis of toxoplasmosis antenatally in order to limit the number of medical abortions. In our series, the most accurate predictor was the detection of the fetal antibody response (specific IgM and IgA) to Toxoplasma.

Animals↗
PubMed1996

Early neonatal diagnosis of congenital toxoplasmosis: value of comparative enzyme-linked immunofiltration assay immunological profiles and anti-Toxoplasma gondii immunoglobulin M (IgM) or IgA immunocapture and implications for postnatal therapeutic strategies.

Diagnostic strategies for congenital toxoplasmosis have changed profoundly in recent years. Immunological diagnostic methods, long considered disappointing, can now be used at a very early stage. Over a 3-year period, 1,050 infants at risk of congenital toxoplasmosis (born to 1,048 mothers infected during pregnancy) were monitored for a minimum of 12 months and a maximum of 7 years. More than 6,000 serum specimens were analyzed by comparative mother-infant immunological profiles (CIPs) based on an enzyme-linked immunofiltration assay (ELIFA) and an immunocapture method for the detection of specific immunoglobulin M (IgM) and IgA. IgG antibodies were also titrated. One hundred three cases of congenital toxoplasmosis were demonstrated. The CIP-ELIFA method had a better diagnostic yield (sensitivity, 90%) than specific IgM and/or IgA detection by immunocapture assay (sensitivity, 77%). By using a combination of these tests, congenital infection was diagnosed in the first month and the first 3 months of life in 90 and 94% of infants with toxoplasmosis, respectively, with a specificity of 99.8% and a positive predictive value of 99% at 8 months of age. This dual diagnostic approach (ELIFA and IgM-IgA immunocapture) is highly efficient and has important implications for therapy. Indeed, early postnatal diagnosis based on objective evidence enables therapy with pyrimethamine-sulfadoxine to be started immediately for 24 months, while spiramycin (which used to be given preventively for 9 to 12 months to all infants at risk) can be stopped after the first 3 months of life.

Animals↗
PubMedDate not supplied

[Characterization of specific IgG, IgM, IgA and IgE isotypes in profound candidiasis].

Enzyme-linked immunofiltration assay technique (Elisa) has been applied to the characterization of G, M, A and E anti-Candida antibodies isotypes specific to cell wall mannans in 201 sera from 126 patients. These sera were studied at the same time using Co-immunoelectrodiffusion and indirect immunofluorescence. In 18 of 21 patients with systemic candidiasis, Elisa demonstrated the presence of antimannan IgG antibodies in sera contemporary of Candida positive blood culture. These IgG were associated with antimannan IgM, A and E in 15 patients. In 37 patients colonized with Candida, used as negative controls, antimannan IgG were detected in 3 cases, and in 2 were associated with specific IgMs. The sensitivity and specificity of Elisa IgM and IgA in the diagnosis of systemic Candidiasis were 85.7% and 81%, respectively. The kinetic study shows that the different isotypes appeared most of the time simultaneously. The evolution of the 4 isotypes beyond the acute episode was variable and without correlation with the clinical status. The decrease of IgG was slower than the one of IgM, IgA or IgE. The systematic research, in at risk patients, of antimannan antibodies using Elisa required simple technology. A simple method should allow to aim at other functional antigens which could be used in a quantitative manner to determine the efficacy of the medical treatment.

Adolescent↗