Hepatic calcifications in a fetus with trisomy 9 that underwent cordocentesis

Foci of calcification were observed at autopsy in the liver of a fetus with complete trisomy 9 on which two cordocenteses had been performed. It is suggested that liver calcifications are a possible complication of the procedure. As several other cases of calcifications in the liver and other organs of fetuses with autosomal trisomies have been described without a history of cordocentesis, further studies should be carried out to determine whether fetuses with chromosomal anomalies are more prone to thrombus formation and embolization.     

Chorionic villus sampling—short-term versus long-term culture in a subtle 2; 18 translocation

Prenatal diagnosis on chorionic villous tissue was performed for a woman with the karyotype 46,XX,t(2;18)(q32;q12)—a subtle ‘difficult’ translocation. The case illustrates the necessity of good quality cytogenetics for accurate prenatal diagnosis. For chorionic villi this can be obtained only with long-term culture.     

Serum PAPP-A measurements in first-trimester screening for Down syndrome

Serum PAPP-A measurements taken from 254 women in the first trimester are reported. Eleven chromosomal abnormalities were detected. The mean serum PAPP-A levels in cases of Down syndrome were 0.44 MOM at 9 weeks gestation, 0.15 MOM at 10 weeks, and 0.29 MOM at 11 weeks. The PAPP-A level at 10 weeks was below those of pregnancies which aborted spontaneously. At 11 weeks, the pregnancies with Down syndrome recorded the lowest PAPP-A levels at that gestation. On this small sample, offering chorionic villus sampling to women with singleton pregnancies and a PAPP-A level below 0.3 MOM (approximately 6.5 per cent of this at-risk group) would have detected all the Down syndrome fetuses at 10 weeks and 50 per cent at 11 weeks without selecting those cases destined to abort. This suggests that serum PAPP-A should continue to be investigated as a potential first-trimester screening test for Down syndrome.     

Petroleum waste biodegradation with porous biomass support system (PBSS) on rotating biological contactor

A laboratory scale study was conducted to assess the feasibility of the new coupling of rotating biological contactor (RBC) plus porous biomass support system (PBSS) using polyurethane foam as porous support media to biodegrade petroleum refinery wastewater. Polyurethane foam was attached on disks of two four-stage laboratory scale cascade connected RBC units.The two RBC units were operated simultaneously at different but constant, flowrates giving hydraulic loading rates of 0.01, 0.02, 0.03, 0.04 m3/m2/d in two runs keeping the same rotational speed 10 r/min throughout. Organic loading was a less controllable factor in this study.For all of the hydraulic loadings, it was found that the removal efficiency of total chemical oxygen demand (TCOD) and oil were above 80 percent. Ammonia nitrogen and phenol removal were above 90 and 80 percent respectively. The maximum biomass concentration within polyurethane foam was about 30 g/m2 in the first stage for 0.03 m3/m2/d hydraulic loading.The results show that t     

Gas chromatographic separation and determination of chloroanthracene isomers on fly ash

An efficient, reproducible and rapid fused silica capillary column gas chromatographic method, in splitless mode, for analysing of the three chloroanthracene isomers is described. The method affords efficient separation and good linearity for each isomer in the range of 0.2 -200 μg/ml. The method can also be used in separation and determination of another thirty three aromatic and their halosubstituted compounds. This paper also presents the applications of the method in analysing of complex products mixture from reaction of the selected aromatic compounds with hydrogen chloride on fly ash surface from municipal incinerator.     

The effect of oxygen tension on colony formation and cell proliferation of amniotic fluid cellsin vitro

The effects of reduced oxygen concentrations in the gas phase over the culture medium on colony formation and cell proliferation were investigated in high and low cell density primary and secondary cultures of amniotic fluid cells. Using two standard culture methods (25 cm² plastic flasks and Leighton type tubes) a significantly reduced culture time was observed at high cell density for mass cultures by incubation within a low oxygen tension gas phase (2.5 per cent to 7.5 per cent O₂) instead of conventional air (18 per cent O₂). At low cell density colony formation was significantly enhanced in cultures grown at reduced oxygen tension. Using gas permeable membranes as support, lowering the oxygen tension from 7.5 per cent to 2.5 per cent yielded an increase in plating efficiency of cells from approximately 5 per cent to 25 per cent, whereas plating efficiency was less than 2 per cent for cells grown at ambient 18 per cent O₂. It is suggested that low oxygen tension in the gas phase is an effective means of enhancing clonal growth in amniotic fluid cell cultures, thereby reducing both culture time and risk of culture failure.