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Therapeutic drug monitoring (TDM) is an important tool in the management of antiretroviral (ARV) therapy. The gold standard for measuring drugs plasma levels is High-Performance Liquid Chromatographic Assay (HPLC) however it is technically-demanding and time-consuming. We evaluated a new immunoenzymatic test (TDM-ELISA, Biostrands, Trieste, Italy) for nelfinavir and its active metabolite M8 in comparison with HPLC. A statistically significant difference in Ctrough between the two different tests was demonstrated but this difference was no longer significant when a value of 29% due to M8 aliquot was deleted. This faster TDM-ELISA may have an important role for TDM in HIV patients taking ARVs.

We evaluated the frequency of seroconversion for toxoplasmosis in seronegative recipients of thoracic solid organ transplants with seronegative or seropositive donors and the efficacy of chemoprophylaxis with pyrimethamine+sulfametopirazine. One hundred and sixty one patients seronegative for toxoplasmosis were followed-up at different intervals. Six patients out of 79 R-/D- and twelve out of 82 R-/D+ seroconverted after chemoprophylaxis interruption. There was no difference between matched and mismatched recipients as to the frequency of seroconversion which therefore could not be related to donor seropositivity. Seroconversions were almost asymptomatic. All positive recipients should be tested if symptoms of infection are present.

Isolates of Toxoplasma gondii, which is responsible for a wide range of clinical manifestations are grouped into three clonal lineages of different virulence in mice. However, it is not clear whether this genotypic pattern is associated with the clinical profile of the disease in humans nor is the geographical distribution of the genotypes known. This is mainly due to difficulties in obtaining parasitic DNA from patients. The available data are therefore limited and originate from acute or congenital infections or from animals. A non-invasive assay is needed to address issues of strain type, geographical distribution and severity of clinical toxoplasmosis. To serotype T. gondii strains, we have developed an enzyme-linked immunosorbent assay (ELISA) that uses polymorphic polypeptides specific to the three clonal lineages and derived from two dense granule antigens, GRA5 and GRA6. Two hundred and fifty-two sera from chronically infected pregnant women from three different European countries and Colombia were investigated. The analysis of genotype-specific antibody response showed a homogeneous type II distribution in the European samples compared with types I and III but no type II in the Colombian population. Our data concord with those obtained from the genotyping of other isolates from Europe and South America. We demonstrated that, despite some limitation due to antigen and/or antibody specificity, serotyping is a promising assay to investigate the relationship between type of strain and severity of the disease.

We investigated the behaviour of the brain during the visualization of commercial videos by tracking the cortical activity and the functional connectivity changes in normal subjects. High resolution EEG recordings were performed in a group of healthy subjects, and the cortical activity during the visualization of standard commercial spots and emotional spots (no profit companies) was estimated by using the solution of the linear inverse problem with the use of realistic head models. The cortical activity was evaluated in several regions of interest (ROIs) coincident with the Brodmann areas. The pattern of cortical connectivity was obtained by using the partial directed coherence (PDC) and investigated in the time and frequency domains, in the principal four frequency bands, namely the theta (4-7 Hz), the alpha (8-12 Hz), the beta (13-30 Hz) and the gamma (above 30 Hz). Results suggest a time-varying engagement of the orbitofrontal circuits that is thought to be involved in the reward value of the stimuli.

The LIAISON system is a fully automated system based on chemiluminescence and antigen bound to magnetic microparticles. The system allows fast and precise measurement of Toxoplasma-specific immunoglobulin G (IgG) and IgM antibody levels and measurement of the IgG avidity index even at low levels of Toxoplasma-specific IgG antibodies in a single step without manual interference. Seven European centers participated in a multicenter evaluation of the LIAISON system. The sensitivity and specificity of the LIAISON system compared to the Sabin-Feldman dye test were 99.3 and 96.8%, respectively. In a comparison of the LIAISON Toxoplasma-specific IgM assay with an immunosorbent agglutination assay, the LIAISON assay had a sensitivity of 96.7% and a specificity of 95.4%. The LIAISON IgG assay showed agreements of 91, 100, and 100% with the AXSYM IgG (Abbott), VIDAS IgG (bioMerieux), and Platelia IgG (Bio-Rad) assays, respectively. The LIAISON IgM assay showed agreements of 95% with the AXSYM IgM and Platelia IgM assays, 96% with the ISAGA IgM assay (bioMerieux), and 97% with the VIDAS IgM assay. The coefficient of correlation between the LIAISON system and the VIDAS Toxoplasma-specific IgG avidity index was 0.81. By use of the Toxoplasma-specific IgG avidity index assay with specific IgM-positive samples, the diagnosis of infection with Toxoplasma gondii in early pregnancy has been improved significantly. The LIAISON avidity assay is a valuable assay for the exclusion of recently acquired infection with T. gondii (less than 4 months) in pregnant women, and it decreases significantly the necessity for follow-up testing.

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.

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.

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.

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.

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.

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.

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.

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.

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.

The authors have evaluated comparatively the diagnostic reliability of four RIA or ELISA tests for the determination of the anti-HBc IgM in serum. Statistically it has been possible to point out significant differences as regards the various Kits.

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.

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.

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.