Use of IgG Avidity test in case definitions of toxoplasmosis in pregnancy.

A survey network for congenital toxoplasmosis (TOXO-NET) was set up in December 1996 in Piedmont (Italy). Participants were asked to classify the infections in pregnant mothers and newborns by the criteria of the European Network on Congenital Toxoplasmosis published by Lebech in 1996. Because the IgG Avidity test is largely employed as a 2nd level test in toxoplasmosis diagnosis and it could be helpful to date infection, the co-ordinators of TOXO-NET suggested including it in the "case definition" of "probable" infection and "unlikely" infection. 117 cases of toxoplasmosis in pregnancy divided into the risk categories under Lebech's criteria were re-examined using the "new" case definitions. 77 out of 117 (65.8%) Toxoplasma gondii infections during pregnancy could be defined with only one serum sample using the IgG Avidity test. The IgG Avidity test proved a useful method to classify the Toxoplasma gondii infections in pregnancy, especially when we had only one serum sample.

A flow injection system with ion-exchange for spectrophotometric determination of copper in rocks.

A flow injection system is proposed for the spectrophotometric determination of copper in rocks. Samples are mineralized by treatment with hydrofluoric and perchloric acids and the solutions analysed after iron III precipitation. Copper is preconcentrated in a small CHELEX-100 resin column placed in the flow system, eluted with 2.5M nitric acid and further mixed with diethanoldithiocarbamate (DEDC) in basic medium. The coloured complex was monitored at 410 nm. With the proposed system, about 2-30 samples are run per hour with low reagent consumption. Beer's law is followed within 0.04 and 2.00, microg/ml. Precision and accuracy were assessed by using reference rock standards from USGS and GSJ with copper content as low as 0.4 microg/g with good precision and accuracy.