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The relationship between hepatitis B viraemia and intrahepatic HBV nucleocapsid proteins (HBcAg and HBeAg) was studied in 18 patients with chronic hepatitis B. Monoclonal antibodies (MoABs) were obtained in BALB/c mice primed with recombinant HBV nucleocapsid proteins. Four MoABs reacting with recombinant proteins gave positive results in competitive assays. Two reacted as anti-HBc and two as anti-HBe. One of them showed a strong affinity for the cytoplasmic, membrane bound antigen (P23e) of infected hepatocytes while the latter showed a higher specificity for serum HBeAg than for the intraheptic antigen. Anti-HBeMoA Bs had a staining capacity for liver cell nuclei comparable with that of polyclonal antibodies. Overall the anti-HBc MoABs stained the liver cell nuclei in 86% of cases, while anti-HBc MoABs stained in 58% of cases. The hepatoeytc cytoplasm was stained by anti-HBc MoABs and anti-HBe MoABs in 64% and 72% of cases respectively. Not one of 12 control liver biopsies was stained. Viraemia (HBV-DNA) was measured by dot blot hybridization and was correlated with the number of hepatocytes containing the nucleocapsid antigen. The highest levels of HBV-DNA (>108 genomes/ml) were detected in patients with prevalent nuclear staining while the lowest ones were observed in those with prevalent eytoplasmic expression of this antigen. The application of anti-HBV-nueleocapsid MoABs in diagnostics requires careful scrutiny since some are specific for the circulating antigen while others show a higher afffinity for the intrahepatic antigen. [ABSTRACT FROM AUTHOR]

An ELISA method was developed for the measurement of toxoplasma IgG antibodies in human serum using antigen-coated polystyrene beads as a solid phase and anti human IgG-horse radish peroxidase conjugate as an enzymatic tracer. In order to assess ELISA sensitivity and specificity, a between methods comparison was made using 'conventional' serological tests as reference (dye-test, crossover-linked immunoassay, passive haemagglutination, indirect immunofluorescence). From an analysis of the group classifications obtained some considerations emerged: the ELISA specificity looks comparable with that of the 'reference' tests, as no sample classified as negative by all these tests was ELISA-positive, and vice versa; ELISA appears to correlate better with haemagglutination and immunofluorescence, on the basis of the respective class frequencies; in particular, the number of positives, which is much lower for the dye-test and crossover-linked immunoassay, suggests that a higher sensitivity is reached in the former cases. [ABSTRACT FROM PUBLISHER]

The control of groundwater and surface water quality in relation to the presence of pesticides and their metabolites is a rather complicated task. National and local authorities with the responsibility to guarantee an adequate quality of water cannot rely on international guidelines for monitoring activities. In a national project, forty-three pesticides and pesticide metabolites were selected on the basis of sale, monitoring and physical-chemical data, and investigated from some of the main Italian agricultural areas, susceptible to pesticide contamination. Twelve compounds were found in the tested water samples at levels exceeding the 0.1 µg/L European Union (EU) limit for drinking water (European Directive 98/83/EC). Maximum levels up to 0.62 were determined. Several water samples were characterized by the simultaneous occurrence of pesticides and their metabolites (up to ten). In some samples, the total concentration of pesticides and their metabolites was higher than the EU limit of 0.5 µg/L. Total triazine concentrations up to 1.02 µg/L were found. In all the cases the highest concentrations were well below the respective guideline values defined by the World Health Organization (WHO) for drinking water quality.

A monoclonal antibody to carcinoembryonic antigen (CEA) (F023C5), belonging to IgG1 class, was obtained by cell fusion technique. Preliminary screening on different tissues was performed with immunoperoxidase staining, which showed good specificity of the antibody for gastric and colorectal carcinomas. F(ab')2 fragments were subsequently prepared and labeled with 131I and 111In. After immunoreactivity check the radiopharmaceuticals were injected intravenously. Sixteen patients with 22 primary or secondary localizations of colorectal carcinoma were studied following the recommendations of the ethical Committee of the Istituto Nazionale Tumori, Milan, Italy. Serial scans were performed after injection of the two radioactive reagents. In vivo pharmacokinetics of the compound was studied. Radioactivity level in surgical specimens was measured, and immunostaining was performed. All tumors were found to express the antigen. Eleven out of 12 tumor localizations of the gastrointestinal tract and three out of ten liver metastases were imaged. Specificity of tumor uptake was assessed by simultaneous injection of an irrelevant antibody.

In vitro experiments selected optimal conditions to radiolabel with 131I the whole immunoglobulin and F(ab')2 fragments of the monoclonal antibody (MoAb) 225.28S to a high-molecular-weight melanoma-associated antigen (HMW-MAA). Injection of the radiolabeled whole immunoglobulin and F(ab')2 fragments of the MoAb 225.28S into eight patients with melanoma resulted in the accumulation of radioactivity in 10 of 18 metastases. This localization is specific because of the close relationship between detection of HMW-MAA in lesions by immunohistochemical techniques and outcome of immunoscintigraphy and because of the different distribution in tumors and adjacent tissues of radiolabeled F(ab')2 fragments of MoAb 225.28S compared with 99mTc-pertechnetate and with radiolabeled F(ab')2 fragments of MoAb 4C4 to hepatitis B surface antigen. F(ab')2 fragments are superior to whole immunoglobulins to perform immunoscintigraphy, since they markedly reduce the background in bone marrow, liver, and spleen. The sensitivity of the procedure allows the detection of lesions with a diameter of at least 1.5 cm and is influenced by the level of the HMW-MAA in lesions and by their anatomical site.