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V Meroni

Publications and source records attributed to V Meroni.

18 recordsLinked to original sources
PubMed1986

IgM-IFA, IgM-ELISA, DS-IgM-ELISA, IgM-ISAGA, performed on whole serum and IgM fractions, for detection of IgM anti-toxoplasma antibodies during pregnancy.

The traditional IgM-ELISA has a better sensibility and specificity than IgM-IFA when these two tests are performed on whole sera, but in many cases (sera titer values of greater than 200 I.U./ml) the presence of IgM antitoxoplasma antibodies can be detected only after purification of IgM fractions. The separations of IgM fractions avoids either false positive results due to the rheumatoid factors or antinuclear antibodies, and false negative results due to the competition between IgG and IgM antibodies. The present investigation has shown that antibody titers obtained by IgM-IFA and traditional IgM-ELISA correlate well with DS-IgM-ELISA and IgM-ISAGA performed on whole serum. The false negative results that frequently occur with IgM-IFA and traditional IgM-ELISA performed on whole sera having sera titer values of greater than 200 I.U./ml in IgG IFA are avoided when the same sera were tested by DS-IgM-ELISA and IgM-ISAGA. All the sera which gave positive results by DS-IgM-ELISA were also positive when tested with IgM-ISAGA. Our researches demonstrate the high specificity and sensitivity of IgM-ISAGA and DS-IgM-ELISA performed on whole serum.

Antibodies↗
PubMed1985

Comparison between IgM-IFA and DS-IgM-ELISA performed on IgM fractions and whole sera in acute acquired toxoplasmosis.

The present investigation has shown that antibodies titers obtained by IgM-IFA performed on pure IgM-fractions, obtained by gel-filtration method, correlate well with DS-IgM-ELISA. False negative IgM-IFA results that frequently occurs with sera having greater than or equal to 200 I.U./ml by IgG-IFA, were not observed with DS-IgM-ELISA: and the 98% of sera positive only after separation of IgM fraction with IgM-IFA, are also positive with DS-IgM-ELISA performed on whole serum.

Chromatography, Gel↗
PubMed1984

A comparison of IHA and ELISA tests in the detection of antibodies to entamoeba histolytica.

In this report we have evaluated the sensitivity and specificity of IHA and ELISA for the detection of anti-amebic antibodies in the serum samples of 147 patients with poor mental and hygienic status hospitalized in mental institutions. Our data have demonstrated a positive agreement between ELISA and IHA on positive sera. The major drawback of IHA is the occurrence of false negative results, 13/82 sera negative in IHA (less than 1/128) are positive in the ELISA. Furthermore, the ELISA is useful for serological diagnosis of amebiasis in the laboratories of low endemic areas.

Antibodies↗
PubMed1984

Detection of IgM-anti-toxoplasma antibodies in acute acquired and congenital toxoplasmosis.

The specificity and sensibility of IgM-IFAT for diagnosis of acute acquired and congenital toxoplasmosis may increase after separation of IgM fractions by simple gel filtration method. In the presence of IFA-IgG titers greater than 250 IU/ml with Remington test less than 1/50, specific IgM antibodies to Toxoplasma gondii should be detected by separation. The separation of IgM seems a necessary step for detecting IgM antibodies by IgM-IFA in the newborn sera.

Acute Disease↗
PubMed1984

An improved method for increasing the sensitivity of direct agglutination test (D.A.T.) to the detection of IgM and IgG anti-toxoplasma antibodies.

The present investigation has shown that the antibody titers obtained by IgG-IFA correlate well with 2-ME-DA (correlation coefficient 0.927, p less than 0.001). These results are obtained when the antibody titers are expressed as IU/ml. Buffer without 2-ME and purification of IgM fractions by simple gel-filtration method seem to be necessary conditions for detecting IgM antibodies by DA test in adult patients. Therefore the DA with these micromodifications has a specificity and sensitivity similar to those of IgG and IgM-IFA tests and would be convenient for laboratories that perform large scale surveys during pregnancy.

Adult↗
PubMed1983

Comparison of ELISA and indirect immunofluorescence in the detection of IgG and IgM antitoxoplasma antibodies.

We have compared ELISA and IFA for the quantitation of IgG and IgM antitoxoplasma antibodies on whole sera and purified IgM fractions. In all the sera examined from adult patients the good correspondence of the two tests is expressed by a correlation coefficient of 0.77 (p = 0.001). However, we have observed that both IgM-ELISA and IgM-IFA performed on whole serum may lead either to false positive results due to presence of rheumatoid factors or to false negative results due to the competition with high level of IgG antibodies. The use of the simplified gel filtration method for separation of IgM fraction allowed the detection of IgM in 40 out of 75 adults patients by IgM IFA and in 39 by the same tests resulted negative if performed on whole serum. The separation of IgM fractions seems a necessary step for detecting IgM antibodies by IgM IFA in 12 of 14 newborns sera with clinical and serological evidence of congenital toxoplasmosis. The conventional IgM ELISA was constantly negative when performed on both whole sera or pure IgM IFA positive fractions of the same newborns.

Animals↗
PubMed1982

Comparison between the complement fixation test LBCF-H100-TTE, IHAT and IgM-IFAT performed on pure IgM fractions in acute acquired and congenital toxoplasmosis.

The use of a gel filtration method allowed us to obtain pure IgM fractions to be tested for specific Toxoplasma serology. The good correlation found in our series between IgM-IFAT and LBCF-H100-TTE performed on pure IgM fractions suggests that LBCF-H100-TTE may be another useful serological test for detection of IgM antibodies although false negative results might occur when LBCF-H100-TTE is performed on IgM fractions of cord sera.

Acute Disease↗
PubMed1981

A new complement fixation test for toxoplasmosis. Comparison with other serological methods.

A new complement fixation test for toxoplasmosis has been compared with the classical test indirect immunofluorescence test (IFAT) and indirect haemoagglutination test (IHAT). Neither false positive or negative results were obtained with LBCF-H100-TTE. Notably these values correlate well with IFA titers. Furthermore LBCF-H100-TTE shows the highest titers in acute cases and its time course is practically superimposable to IFAT. The differences obtained performing these different tests on the preferential detection of different antigen antibodies systems by these 3 tests are discussed.

Complement Fixation Tests↗
PubMed1981

Reliability of IgM-IFA and IgM-IHA tests on pure IgM fractions obtained by a simple gel filtration method in acquired and congenital toxoplasmosis.

We have devised a rapid and inexpensive gel filtration method to separate IgM fractions from small amounts of serum. These fractions have been titrated with IgM-IFAT and IgM-IHAT, and their titers have been compared with those obtained on whole serum. The results show that the separation of IgM from IgG allows detection of IgM antibodies in many cases of acquired toxoplasmosis, especially in cases of congenital toxoplasmosis. False positive results due to the presence of rheumatoid factors are also avoided. The IHA test performed on IgM fractions is constantly negative.

Adult↗
PubMed1981

Congenital toxoplasmosis: a serologic screening of 963 mothers and their children at birth.

An investigation carried out according to a predetermined serologic screening sought to evaluate the prevalence, level, and quality of fluorescent anti-Toxoplasma antibodies in a population sample of a certain district. The most important issues concern the risk of congenital toxoplasmosis for the above-mentioned subjects, the level of serotiter for expected risk, and the features of our screening protocol as regards thoroughness and the possibility of early diagnosis.

Adolescent↗
PubMed1980

Immuno-electron microscopic localization of antigenic sites for specific immunoglobulins G and M on Toxoplasma gondii surface.

The results of immuno-electron microscopic reaction obtained with anti-IgG and/or anti-IgM ferritin conjugated sera after the inter-reaction of RH strain with specific IgG and/or IgM immunosera, confirm: 1) antigenic sites for specific immunoglobulins both IgG and IgM localization on superficial membrane of pellicular complex; 2) the saturation of common antigenic surface sites due to the competition between IgG and IgM; 3) the competitive prevalence of IgG even if IgM concentration is relatively high in unfractioned immunosera. The practical application of such results is discussed in relation to the specific tests for IgM evidentiation during primary response.

Animals↗
PubMed1980

Kinetics of IgM and IgG antibodies in mice experimentally infected with cystogenic strain of Toxoplasma gondii.

Mice were infected with a "cystogenic" strain of T. gondii and sera obtained at different times were tested using DT and IFAT (cell wall antibodies tests) and IHAT (performed with extractive cytoplasmic antigen). We found different kinetics of DT- and IFAT- versus IHAT-titers: IHAT is negative during the early phase of the experimental infection when DT and IgM-IFAT are already positive. Furthermore IgM antibodies were never found against cytoplasmic antigens by the IHAT method. At weekly intervals after the experimental infection a biological test was also performed using samples of different organs. We found that one week after the infection only the brain was constantly positive in the biological test. The antibody pattern was similar in every positive test irrespective of the source and size of the material used for the inoculum. These data suggest that the result of a biological test may be available earlier (already after 7 days) if a test for antibodies against cell wall antigens is performed on the IgM fraction of the mouse serum.

Animals↗
PubMedDate not supplied

[Prenatal diagnosis of congenital toxoplasmosis].

Primary Toxoplasmosis is devoid of any consequences in the mother in most cases, while the fetus can suffer serious damages following transplacental passage of the parasite. This is probably due to its limited immunocompetence. 440 women have been seen for suspected primary infection during pregnancy: clinical and serological parameters excluded infection in 62% of the cases. In 168 cases primary infection was likely and they underwent therapy with Spiramycin 3 grams per day to prevent placental and fetal colonization: 53 cases were elected for invasive prenatal diagnosis. Amniotic fluid was obtained by amniocentesis and fetal blood by ultrasound guided cordocentesis and by fetoscopy: the samples were analyzed for specific anti Toxoplasma IgM and sent for isolation of the parasite. Diagnosis of fetal infection was made in 4 cases: 3 cases had specific IgM in cord blood, 1 case showed intracranial calcifications by ultrasound screening. Fetal infection rate is thus below 10% and prenatal diagnosis avoids unjustified interruption of pregnancies complicated by maternal toxoplasmic infection.

Adult↗