Umbilical cord haematoma as a complication of intrauterine intravascular blood transfusion

Between October 1985 and February 1989, 49 ultrasound-guided intravascular fetal blood transfusions were performed in 16 patients (14 with rhesus (Rh) isoimmunization, 2 with non-immunologic hydrops fetalis (NIHF)). As an intra-operative complication, perivascular haematoma of the cord occurred in three patients (7 per cent). In two cases, fetal bradycardia necessitated delivery by Caesarean section at 30 and 32 weeks' gestation, respectively. In the third case, fetal bradycardia developed during transfusion, at 31 weeks' gestation, but normalized within 3 min. The baby was delivered as planned at 36 weeks of gestation, after another transfusion at 34 weeks. Dislodgement of the needle tip into perivascular tissue, caused by sudden fetal or maternal movements, is the reason for this complication. The haematoma develops as a result of delayed recognition and continuous transfusion into Wharton' s jelly. Cord haematoma may be diagnosed in time by continuous ultrasound imaging, as illustrated in case 3. To minimize the risk of needle dislodgement during transfusion, sedation of the mother and complete immobilization of the fetus by injecting a short-acting muscle relaxant into the umbilical vessel are recommended.     

Ontogeny of fetal liver glucose-6-phosphatase activity

A reliable and sensitive microassay for the measurement of liver glucose-6-phosphatase is described. Human fetal liver was assayed for glucose-6-phosphatase activity from 7.5 to 24 weeks of gestation and was found to have a mean activity of 2.11 nmol per min per mg of protein. This was approximately 30 per cent of the postnatal controls assayed by the same method, but there was no evidence of a change in activity during the gestational period examined. If fetal liver tissue can be reliably obtained, it may be possible to determine a deficiency of glucose-6-phosphatase in fetuses who are at risk.     

Scalar transport from point sources in the flow around a finite-height cylinder

This paper presents a large eddy simulation of mass transfer in the flow around a surface-mounted finite-height circular cylinder. The study was carried out for a cylinder with height-to-diameter ratio of 2.5 and a Reynolds number based on the cylinder diameter of 44000. The approach flow boundary layer had a thickness of about 10% of the cylinder height. A tracer was released at various levels upstream of the cylinder. The effect of the release position in the subsequent spreading and dilution of the plumes is analyzed. It is found that a tracer released at the top or at mid-height is entrained into the recirculation zone behind the cylinder, and therefore presents similar plume evolution in the far wake in both cases. If the tracer is released at around three-quarters of the height of the cylinder, it is not significantly entrained by the main recirculation region, leading to smaller rates of spreading of the plume. Finally, if the tracer is released near the floor, the plume is entrained by the horseshoe vortex that wraps around the cylinder, leading to a large lateral spreading of the plume, remaining always near the floor.