Hazel Thom

Prenatal diagnosis and family studies in a case of propionicacidaemia

In a family with a history of two neonatal deaths, propionicacidaemia was diagnosed retrospectively from stored plasma as the cause of the second death during the mothers next pregnancy. Amniocentesis was performed and a culture of amniotic cells was assayed for propionyl CoA carboxylase activity. The absence of any detectable propionyl CoA carboxylase activity allowed the prenatal diagnosis of propionicacidaemia to be made. Treatment with biotin and a modified aminoacid diet was started in the immediate postnatal period. Investigation of propionyl CoA carboxylase in leucocytes from the parents, siblings and other relations of the patient failed to demonstrate intermediate enzyme activities in even the parents, who were presumably heterozygotes for this condition.

Observations on neonatal tears.

In over 90 per cent of healthy infants of normal birth weight, gamma-A globulin was first detected (>0.5 mg. per 100 ml.) in tears of infants between 10 and 20 days of age. Its appearance was slightly delayed in infants of low birth weight, but less markedly than was serum gamma-A globulin, so that in a proportion of low birth weight infants tear gamma-A globulin was detected first. No relationship was evident between conjunctival cultures from healthy infants and tear gamma-A globulin. Infective conjunctivitis in the first week of life caused significantly earlier appearance of tear gamma-A globulin. Gamma-A globulin was found in the tears of healthy infants throughout the neonatal period, with lowest concentrations in the second week of life when gamma-G globulin was undetectable (

THE ORIGIN OF AMNIOTIC FLUID LECITHIN

Lecithin has been measured in amniotic fluid, pharyngeal aspirate, fetal and maternal plasma and fetal membranes from the same pregnancy. In the amniotic fluid from a term pregnancy 79 per cent of the lecithin is found in the reconstituted precipitate of centrifuged fluid. It is suggested that the lecithin of amniotic fluid may originate from sources other than fetal lung and that lecithin concentration is therefore a measure of overall fetal maturity.

Histamine metabolism in asthma

Abstract Histamine and 1-methyl-imidazole-4-acetic acid, the end product of histamine metabolism via the ring-N methylation pathway, were measured in urine from asthmatic and nonasthmatic children on a histamine-restricted diet. No significant differences were found between the relative output values that could distinguish the asthmatic from the nonasthmatic children. The intermediary metabolite, methylhistamine, was also measured in some of these urine specimens, and no obvious differences were found between the proportions of the three substances that would suggest impairment of the methylation pathway of histamine metabolism in asthma.

Immunoglobulins in Haemolytic Disease of the Newborn

Concentrations of IgG, IgA and IgM were measuredin the sera of infants with haemolytic disease of the newborn and I control infants from birth to the age of 6 months. No significant Differences were found between the IgG, IgA and IgM concentrations in haemolytic disease and control infants of comparable birth weight. Inhibition of IgG synthesis in the infant from the presence of antiglobulins in transfused blood or from interference with a feed-back control mechanism based on Gm phenotype could not be demonstrated.

Pregnancy outcome in relation to the concentration and concanavalin A reactivity of α-fetoprotein and the presence of acetylcholinesterase activity in amniotic fluid

SummaryReactivity of α-fetoprotein with concanavalin A and detection of acetylcholinesterase activity in amniotic fluid were evaluated as secondary tests for fetal neural tube defect in pregnancies with a high or a low risk of such a defect. A retrospective study was done on 72 fluids and a prospective study on selected samples from 342 fluids in all of which total a-fetoprotein had been measured. Both additional tests were useful in discriminating between normal and abnormal outcome in pregnancies with raised total α-fetoprotein.In the prospective series there were four false positive total α-fetoprotein tests and one false positive acetylcholinesterase test in viable pregnancies without fetal abnormality. None of the three tests was falsely negative for fetal neural tube defect.Specific abnormality and other poor pregnancy outcomes were much commoner when amniocentesis followed from high maternal serum α-fetoprotein than any other indication.