XII Ecdysone Workshop July 22–26, 1996 Barcelona,Spain

XII Ecdysone Workshop July 22–26, 1996 Barcelona, Spain     

Effects of atmospheric gases on terrestrial plants and critical levels of air pollution

An integrated approach was developed to determine the critical levels of air pollution for ecological standard setting based on the unified index of biological response, by taking into account the effects of all pollution components simultaneously. An empirical model of plant productivity was taken as the dose response model for gaseous pollutant effect on the productivity of trees and the annual productivity of plants was used as the above mentioned index. The CO2 increase in the lower atmosphere was considered to potentially increase plant productivity and NO2 was estimated as neutral while being dangerous for plants as a chemical precursor of ozone or as a source of acidification. The maximum permissible chronic O3 and SO2 levels for trees were estimated and it was found that O3 is much more phytotoxic, as compared to SO2 , with a rather narrow range of permissible levels (27-33 ppb) which complicates its monitoring and control.     

Prenatal cytogenetic diagnosis after transabdominal chorionic villus sampling in the first trimester

First trimester prenatal cytogenetic diagnosis was attempted in 350 pregnancies after trans-abdominal chorionic villus sampling. The cytogenetic investigation was performed using both a short-term method (24 h incubation) and cell culture. Adequate samples were obtained in 99·1 per cent and in all these cases the fetal karyotype was established. A chromosome abnormality was found in 2·0 per cent of cases. A discrepancy between the karyotype obtained after 24 h incubation and the karyotype in cell culture was observed in 2·3 per cent. Maternal cell contamination in the cultures was confirmed in 13 of 181 cases where the 24 h incubation revealed a male karyotype. Studies of culture morphology showed that colonies of convoluted cells may serve as a marker for contamination with maternal cells in culture. For the present, we recommend using a short-term method as well as cell culture for cytogenetic investigation until the problems with karyotype discrepancy and maternal cell contamination have been further clarified.     

Maternal sex chromosome mosaicism diagnosed by amniocentesis and percutaneous umbilical cord sampling

We present a remarkable chain of events in which percutaneous umbilical cord sampling was performed in an attempt to clarify a situation of possible fetal sex chromosome mosaicism in an amniotic fluid culture and led to the discovery that the mother herself had a 45,X/46,XX/ 47.XXX chromosome constitution. This may have simply represented the chance concurrence of pseudo-mosaicism in the amniotic fluid culture of a woman with an abnormal sex chromosome constitution, but it is also possible that the 45,X colony was maternal in origin. Although clearly a most unusual circumstance, the possibility should be kept in mind when termination of a pregnancy is being considered because of apparent mosaicism in a prenatal diagnostic study.     

A routine method for storing lymphocytes for repeated isolation of DNA

A protocol for easy storage and later expansion of lymphocyte populations is given. Compared with methods using transformed cell lines, the method has a number of advantages for repeated production of cells for the isolation of DNA in amounts sufficient for use in diagnostic DNA technology.     

Maternal Serum CA 125 for aneuploidy detection in early pregnancy

Maternal serum CA 125 levels were determined at 9–11 menstrual weeks for 26 cases of trisomy 13 (n = 4), trisomy 18 (n = 7), trisomy 21 (n = 15), and appropriate controls. There were no statistically significant differences between groups.     

Reproductive behaviour and prenatal diagnosis following genetic termination of pregnancy in women of advanced maternal age

One hundred and fifty-one women of advanced maternal age who underwent genetic termination of pregnancy (TOP) were studied for their reproductive behaviour and the type of procedure for prenatal diagnosis in a subsequent pregnancy. A total of 59 women (39 per cent) had a further pregnancy. In all continuing pregnancies prenatal diagnosis was performed, of which 75 per cent consisted of chorionic villus sampling (CVS). Reproductive behaviour following a genetic termination was negatively correlated with maternal age and parity. Both reproductive behaviour and the choice to undergo a diagnostic procedure in the next pregnancy were independent of the type of diagnostic procedure in the previous affected pregnancy.