Search PubMed⌕ Search

Biomedical subjects

L Barron

Publications and source records attributed to L Barron.

47 records · Page 3Linked to original sources
PubMed1980

The potential of mid-trimester maternal plasma alpha-fetoprotein measurement in predicting infants of low birth weight.

Maternal plasma alpha-fetoprotein (AFP) was measured at mid-trimester in 113 women who subsequently were delivered of a singleton liveborn infant weighing less than 2.5 kg and in 113 matched controls whose infants weighed more than 2.5 kg. Plasma AFP levels were significantly higher in the subjects than in the controls, while 10 of the subjects and only 3 of the controls had values above 2.0 times the median. The higher AFP concentrations were seen both in pregnancies in which the outcome was a small premature infant and in those in which it was a small-for-dates baby.

Female↗
PubMed1979

Significance of elevated mid-trimester maternal plasma-alpha-fetoprotein values.

In a prospective trial of 15,481 pregnancies, 667 women (4.3%) had two sequential mid-trimester plasma-alpha-fetoprotein (A.F.P.) values above 2 times the median. The outcome of these pregnancies was open neural-tube defect (12.4%), birthweight less than 2.5 kg (10.3%), twins (9.8%), fetal wastage (9.5%), perinatal death (2.6%), other (1.3%), and "normal" singleton (54.1%). At higher A.F.P. cutoffs the proportion of "normal" singleton pregnancies declined rapidly, being 19% at 3 times the median and 9% at 4 times the median. If it is assumed that ultrasonography and amniotic-fluid A.F.P. assay can detect twins and most cases of neural-tube defect, the outcome of the residual pregnancies is still strongly influenced by plasma-A.F.P. level. Thus at a cut-off of 4 times the median two-thirds of the pregnancies in this residual group will end in spontaneous abortion, stillbirth, or neonatal death. It is suggested that counselling of women taking part in A.F.P. screening programmes should be strongly influenced by maternal plasma-A.F.P. levels, even if ultrasonographic findings and amniotic-fluid levels are normal.

Birth Weight↗
PubMed1979

The relation between maternal plasma alpha-fetoprotein and birth weight in twin pregnancies.

In the course of routine screening for neural tube defects, maternal plasma alpha-fetoprotein (AFP) was measured between 15 and 23 weeks of gestation in 64 twin pregnancies. Women with AFP levels more than twice the median for singleton pregnancies gave birth to infants with significantly decreased birth weights. Women with AFP less than the median also tended to produce twins with decreased birth weights. The distribution of gestations at delivery suggested that in twin pregnancies low AFP values gave an early warning of growth retardation while high values signal possible premature delivery.

Birth Weight↗
PubMed1978

Serum alphafetoprotein in cystic fibrosis of the pancreas.

Serum alphafetoprotein concentrations were measured by three different types of radioimmunoassay in 30 patients with cystic fibrosis of the pancreas and in 55 controls. The highest value obtained in cystic patient was 10.2 ng/ml and in a control 10.8 ng/ml. These are within published normal limits. Previously reported large increases in serum AFP in patients with cystic fibrosis and in heterozygote carriers have not been confirmed.

Cystic Fibrosis↗
PubMed1978

Maternal plasma alpha-fetoprotein screening for fetal neural tube defects.

Maternal plasma alpha-fetoprotein (AFP) screening for fetal neural tube defects (NTD) was used as a part of routine antenatal care in three hospitals over a 26 month period. Blood samples were obtained for plasma AFP measurement at 15 to 20 weeks gestation from 6377 women, representing 79 per cent of antenatal bookings. The outcome of pregnancy was ascertained in 96 per cent of patients: 13 cases of anencephaly and 7 of open spina bifida were detected by plasma screening and a further 3 cases of open NTD through the mother's previous medical history and amniotic fluid determination. Four fetuses with open NTDs and four with closed NTDS were not detected by plasma AFP measurement and the detection efficiency for open NTDs was thus 83 per cent. Integration of screening into the existing pattern of antenatal care required only minor alterations in clinic schedules. Some extra time was needed for explanation of the objectives of the study, for ultrasound examination and for amniocentesis. Eight patients declined the offer of a plasma test, while only one refused an amniocentesis.

Amniotic Fluid↗
PubMed1977

Maternal serum-alpha-fetoprotein measurements as an early indicator of low birth-weight.

In a prospective trial of 4224 pregnancies, 103 women had serum-alpha-fetoprotein (A.F.P.) above 2-3 times the median value for their stage of gestation. 10-7% of these delivered infants with birth-weights less than 2-5 kg. This was significantly greater than the rate of 4-2% for low-birth-weight infants in the general population. At higher multiples of the median serum-A.F.P. value the proportion of pregnancies leading to low-birth-weight infants was even greater. It is suggested that early identification of pregnancies with high risk of premature delivery may be an important corollary of maternal serum A.F.P. screening.

Birth Weight↗
PubMedDate not supplied

Prenatal diagnosis of cystic fibrosis using a monoclonal antibody specific for intestinal alkaline phosphatase.

A monoclonal antibody (AAP-1), specific for the intestinal isoenzyme of alkaline phosphatase (ALP), has been used to develop an immunoassay for amniotic fluid samples. Values in the immunoassay correlated closely with those obtained by direct determination of phenylalanine-inhibitable ALP. A panel of 124 control second-trimester amniotic fluids and 21 fluids with a 1 in 4 risk of a cystic fibrosis fetus were examined in the immunoassay. Eight of 10 affected cases had values below an arbitrary cut-off of one third median, while all the non-affected cases were above this level. Almost identical results were obtained by enzymatic determination of phenylalanine-inhibitable ALP. However, in both systems the false positive rate (control fluids with values below one third median), was unacceptably high. It is pointed out that at present the most effective system for the prenatal diagnosis of cystic fibrosis is achieved by measuring the ratio of intestinal to total ALP in amniotic fluid supernatants. This is probably best effected by enzymatic assay in the presence of phenylalanine and homoarginine inhibition.

Alkaline Phosphatase↗
PubMedDate not supplied

Distinguishing hygroma and amniotic fluid.

Fluid from cystic hygromata can be distinguished from amniotic fluid by measurement of alkaline phosphatase (ALP) isoenzymes. The former has a serum-type ALP, made up largely of the liver/bone/kidney isoenzyme and virtually no intestinal isoenzyme. Second trimester amniotic fluid ALP contains approximately 80 per cent intestinal isoenzyme.

Acetylcholinesterase↗
PubMedDate not supplied

Biochemical analysis of meconium in fetuses presumed to have cystic fibrosis.

A series of proteins (albumin, transferrin, alpha 1-antitrypsin, alpha-fetoprotein and pancreatic oncofetal antigen) and enzymes (gamma-glutamyltranspeptidase, aminopeptidase M, alkaline phosphatase, alpha-glucosidase and protease) was measured in fetal meconium extracts. There were 19 fetuses thought to have cystic fibrosis (CF), 13 with neural tube defects, three with chromosome abnormalities and 19 normal controls, all with gestational ages between 18 and 21 weeks. With the exception of alpha-fetoprotein, all the proteins and enzymes were significantly elevated in the CF meconium extracts. The most definitive indicator of a CF fetus was the albumin concentration, where the mean level was five times that found in the control groups. However, five of 19 fetuses assumed to have CF had albumin in the normal range. In these cases the meconium protease levels were grossly elevated. Furthermore, in the same five fetuses meconium concentration of pancreatic oncofetal antigen, a protein synthesized in the fetal pancreas, was also greatly raised. We suggest that post-mortem examination of a fetus thought to have CF should include measurement of meconium albumin, protease and pancreatic oncofetal antigen.

Abortion, Induced↗
PubMedDate not supplied

Post-Christmas blues: a rare cause of cyanosis.

A patient was referred for urgent evaluation of cyanosis. Although she had symptoms and signs of an upper respiratory tract infection, she had a normal cardiorespiratory examination and normal transcutaneous oxygen saturation. Further evaluation revealed a benign cause for the cyanosis.

Adolescent↗