Glycine/serine ratio and the prenatal diagnosis of non-ketotic hyperglycinaemia

We describe our experience of prenatal diagnosis of non-ketotic hyperglycinaemia in four at-risk pregnancies using the glycine/serine ratio in amniotic fluid obtained between 18 and 20 weeks of gestation. All glycine levels were in the normal range. Serine levels were normal in two patients and borderline in the others. Glycine/serine ratios were normal in two patients, moderately increased in one patient ( + 3 SD), and highly increased in one patient ( + 8 SD). All the children were perfectly normal at birth. Because of this false-positive prediction and the false-negative prediction recently reported, we suggest that this unreliable method should not be used.     

Citrulline in amniotic fluid and the prenatal diagnosis of citrullinemia

We report relatively high citrulline concentration in amniotic fluid of a citrullinemic fetus suggesting that prenatal detection of this condition could be done on this basis in conjunction with a direct or an indirect determination of argininosuccinate synthetase activity in amniotic fluid cells.     

Eleventh week amniocentesis for prenatal diagnosis of some metabolic diseases

We report the results of 23 prenatal diagnoses performed at the 11th or 12th week of gestation by the simultaneous analysis of chorionic villi (for direct or indirect enzymatic analysis) and cell-free amniotic fluid (for search of accumulated catabolites). For six cases of citrullinaemia, four cases of argininosuccinic aciduria, seven cases of propionic acidaemia, and six cases of methylrnalonic acidaemia, three discrepancies were observed between the two methods used. The amniotic fluid analysis for accumulated catabolites seems to be a safe method and should always be used in conjunction with the enzymatic assays performed for the prenatal diagnosis of these diseases.     

Effect of phosphogypsum addition in the composting process on the physico-chemical proprieties and the microbial diversity of the resulting compost tea

Environmental Science and Pollution Research - Phosphoric acid production and olive oil production are among the most important economical sectors in Tunisia. However, they generate huge amounts of...     

Improving the prenatal diagnosis of citrullinemia using citrulline/ornithine+arginine ratio in amniotic fluid

Prenatal diagnosis of citrullinemia is performed using a direct argininosuccinate synthetase (ASS) assay on chorionic villi (CV) and citrulline concentration measurement in early amniotic fluid (AF). Here we report the results of 40 prenatal diagnoses performed using this method, discuss the difficulties encountered in interpreting the results, and propose the use of the citrulline/ornithine+arginine ratio (which is more discriminatory than citrulline concentration alone) when performing prenatal diagnosis of citrullinemia. Copyright © 2002 John Wiley & Sons, Ltd.     

Prenatal diagnosis of ornithine transcarbamylase deficiency: Results in SPFASH mice

Ornithine transcarbamylase (OTC) deficiency is a human X-chromosome-linked disease (McKusick 31125). The presence of OTC activity in the human placenta encouraged us to examine the possible diagnosis of the disease in an animal model (Spf^ash mice) by enzymatic assay on placental samples. A significant positive correlation (P< 0·02) was found between placental and hepatic activities; the pH dependence of OTC was similar in the placenta and liver when compared within normal or homozygous mutant mice. The apparent K_m (ornithine) and K_m (carbamoylphosphate) values of the enzyme did not show any significant differences when compared in both placentae and livers of normal fetuses. The use of OTC assay in the placenta for prenatal diagnosis of OTC deficiency in mouse fetuses obtained by the crossbreeding of Spf^ash/+ with +/Y has shown that our method has good diagnostic value. We made the diagnosis of OTC deficiency in male fetuses with a sensitivity and a specificity of 1·0. The + gene from the father in Spf^ash/ + animals is preferentially inactivated in extraembryonic tissues, explaining why very low placental OTC activity was observed in 12 of the 18 female fetuses studied. Because these 12 females have variable OTC activity in their livers, it is not possible to appreciate the true residual activity in their livers by measuring this activity in the placenta.     

Prenatal diagnosis of propionic acidemia in chorionic villi by direct assay of propionyl CoA carboxylase

Prenatal diagnosis of propionic acidemia was achieved by the direct assay of propionyl CoA carboxylase in chorionic villi. The diagnosis was confirmed by determination of methylcitrate in amniotic fluid and measurement of propionyl CoA carboxylase in the liver from the abortion. Discrepancy between [¹⁴C]-propionate incorporation into protein of chorionic villi or cultured chorionic cells and propionyl CoA carboxylase activity is reported.