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D L Economides

Publications and source records attributed to D L Economides.

71 records · Page 4Linked to original sources
PubMed1992

Computerized measurement of heart rate variation in fetal anemia caused by rhesus alloimmunization.

OBJECTIVE: The purpose of this study was to examine the relationship between fetal heart rate variation and fetal hematocrit. STUDY DESIGN: In 36 red-cell alloimmunized pregnancies (mean gestational age 30, range 25 to 36 weeks) 65 computerized fetal heart rate recordings were obtained before ultrasonographically guided fetal blood sampling for the measurement of fetal hematocrit. The recordings were captured and analyzed by a microcomputer on-line. Fetal heart rate variation in anemic fetuses was accurately measured. RESULTS: Significant positive correlations between short-term or long-term heart rate variation and fetal hematocrit have been demonstrated even after adjusting for the effect of gestation (r = 0.60, n = 65, p less than 0.01, y = 19.264 + 0.913x - 0.003x2; r = 0.52, n = 65, p less than 0.01, y = 21.13 + 0.858x - 0.003x2, respectively). The relationship was best described by a quadratic model. When short-term variation was less than 5 milliseconds or long-term variation was less than 30 milliseconds, the positive predictive values for fetal hematocrit of less than 30 were 85% and 90%, and the negative predictive values 56% and 57%, respectively. CONCLUSION: Computerized recording and analysis of fetal heart rate variation may prove to be a useful noninvasive tool for assessing fetal anemia in red-cell alloimmunization.

Anemia↗
PubMed1992

Folate and vitamin B12 concentrations in maternal and fetal blood, and amniotic fluid in second trimester pregnancies complicated by neural tube defects.

OBJECTIVE: To investigate maternal and fetal folate and vitamin B12 concentrations in pregnancies affected by neural tube defects (NTD). DESIGN: Measurement of folate and vitamin B12 concentrations in amniotic fluid, fetal blood and maternal blood samples in midgestation. SUBJECTS: 32 women undergoing termination of pregnancy at 14-21 weeks gestation for social reasons (n = 24) or for fetuses with neural tube defects (n = 8). INTERVENTIONS: Fetoscopy before intra-amniotic injection of prostaglandins. RESULTS: In normal pregnancies there was a positive correlation between maternal and fetal serum folate, and the fetal serum and red blood cell folate concentrations were higher than the maternal. There were no differences in amniotic fluid, maternal blood or fetal blood folate concentrations between pregnancies with NTD and normal pregnancies. Although amniotic fluid vitamin B12 was lower in pregnancies with NTD, maternal serum vitamin B12 concentration was not reduced. CONCLUSION: In this small group of pregnancies with NTD at mid-gestation there is no evidence to suggest folate or vitamin B12 deficiency.

Abortion, Spontaneous↗
PubMed1991

The fetal concentrating index as a gestational age-independent measure of placental dysfunction in intrauterine growth retardation.

In previous work we have shown, using cordocentesis to obtain fetal blood, that fetuses with intrauterine growth retardation are hypoxic and suffer from in utero starvation of nutrients. In this study we have developed gestational age curves for fetal blood amino acids and carnitine that now allow the development of a new parameter, the fetal concentrating index, which is the numeric mean of the fetal/maternal ratio of six essential and nonessential concentrated amino acids. Our data have shown that this index does not vary with gestation in either normal pregnancies (1.83 +/- 0.42, mean +/- SD) or pregnancies with intrauterine growth retardation (1.46 +/- 0.38), but the index is markedly reduced in intrauterine growth retardation (p less than 0.001). These results suggest that, because cordocentesis has become very safe in experienced hands, cordocentesis to obtain the fetal concentrating index might ethically be obtained in cases of fetuses at risk for intrauterine growth retardation, to devise strategies for intervention before the onset of severe hypoxia and morphometric changes.

Amino Acids↗
PubMed1991

Metabolic and endocrine findings in appropriate and small for gestational age fetuses.

The oxygenation and metabolism in appropriate (AGA) and small for gestational age (SGA) fetuses has been investigated by cordocentesis. The umbilical venous and arterial pO2 and pH decrease with gestational age while pCO2 increases and blood lactate concentration does not change. The mean umbilical venous blood glucose concentration is higher than in the umbilical artery indicating that there is fetal glucose uptake from the placenta. Similarly, the maternal glucose concentration is higher than the fetal and the levels in the two compartments are significantly correlated. The plasma insulin concentration increases exponentially with gestation reflecting the progressive maturation of the fetal pancreas. The fetal plasma cortisol does not change but the fetal plasma ACTH increases with gestation. Fetal plasma triglyceride concentration decreases exponentially with gestation and this is likely to be the result of increased utilization by the fetus for deposition into adipose tissue. There is a high correlation between fetal and maternal levels for individual amino acids and the concentration in the fetus is higher than in the mother, supporting the active transport of amino acids by the placenta. Some SGA fetuses are compromised by hypoxemia, hypercapnia, hyperlacticemia and acidosis, are starved of glucose and amino acids, and are hypertriglyceridemic. Furthermore, some of these fetuses are hypoinsulinemic and the degree of hypoinsulinemia is disproportional to the degree of hypoglycemia suggesting pancreatic dysfunction. In SGA fetuses the plasma cortisol is increased and the plasma ACTH decreased. Knowledge of human fetal oxygenation and metabolism may help in deciding the optional timing of delivery but may also constitute a basis for future fetal therapy in the form of oxygen and nutrient supplementation.

Adrenocorticotropic Hormone↗
PubMed1990

Hypertriglyceridemia and hypoxemia in small-for-gestational-age fetuses.

Plasma triglyceride concentration and blood oxygen tension were measured in samples obtained by cordocentesis from 35 small- and 54 appropriate-for-gestational-age fetuses at 18 to 36 weeks' gestation. In the appropriate-for-gestational-age fetuses there was an exponential decrease in plasma triglycerides with gestation. Some small-for-gestational age fetuses were hypertriglyceridemic and the degree of this biochemical disturbance was significantly correlated with the degree of fetal hypoxemia.

Adipose Tissue↗
PubMed1989

Plasma insulin in appropriate- and small-for-gestational-age fetuses.

Plasma insulin and blood glucose levels were measured in umbilical venous samples obtained by cordocentesis from 42 small-for-gestational-age and 68 appropriate-for-gestational-age fetuses at 17 to 38 weeks' gestation. In the appropriate-for-gestational-age fetuses plasma insulin and the insulin/glucose ratio increased exponentially with gestation, reflecting the progressive maturation of the pancreas. Maternal blood glucose concentration, not fetal plasma insulin, was the major determinant of fetal blood glucose concentration. In some small-for-gestational-age fetuses hypoinsulinemia and hypoglycemia were found; the two were significantly correlated. However, the fetal insulin/glucose ratio was lower in small-for-gestational-age fetuses than in appropriate-for-gestational-age ones, suggesting that hypoinsulinemia in a small-for-gestational-age fetuses is not only the result of hypoglycemia but also a consequence of pancreatic dysfunction. The degree of fetal smallness did not correlate with plasma insulin or with the insulin/glucose ratio. These findings suggest that insulin may influence fetal growth through its action on nutrient uptake and utilization but it is not the primary determinant of fetal size.

Adult↗
PubMed1989

Blood glucose and oxygen tension levels in small-for-gestational-age fetuses.

Blood glucose and oxygen tension levels were measured in umbilical venous and arterial samples obtained by cordocentesis from 63 small-for-gestational-age fetuses. Reference ranges for these parameters were established by measurement of blood glucose (n = 122) and oxygen tension (n = 189) levels in appropriate-for-gestational-age fetuses that were undergoing cordocentesis in the prenatal diagnosis of congenital abnormalities. The fetuses were subsequently found to be unaffected by the condition investigated. In the small-for-gestational-age fetuses, the maternal-to-fetal blood glucose concentration gradients for the umbilical vein and artery correlated significantly with the degree of fetal hypoxia but not with the degree of fetal smallness. Furthermore, there was no significant difference in the relationship of maternal and fetal blood glucose concentration gradient and hypoxia between the umbilical venous and arterial samples, which suggests that the major cause of hypoglycemia in small-for-gestational-age fetuses is reduced supply rather than increased fetal consumption or decreased endogenous production of glucose.

Blood Glucose↗
PubMed1989

Plasma atrial natriuretic peptide in human fetus: response to intravascular blood transfusion.

To investigate whether atrial natriuretic peptide is present in the human fetal circulation and changes in response to fetal blood volume expansion, the concentration of plasma atrial natriuretic peptide was measured by radioimmunoassay in samples obtained by cordocentesis. Twenty-four patients referred for intravascular blood transfusion because of red cell isoimmunization at 21 to 35 weeks' gestation were studied. Plasma atrial natriuretic peptide concentrations in fetal blood (median, 8.0 pmol/L; range, 1 to 27.3) were significantly higher than those of 25 young 18- to 32-year-old adult control subjects (median, 4.5 pmol/L; range, 1 to 11.3, p less than 0.002 but similar to those found in the umbilical cord blood of 10 normal neonates immediately after delivery (median, 7.35 pmol/L; range, 2.7 to 15.5). In seven patients in whom fetal and maternal plasma atrial natriuretic peptide was measured simultaneously, all fetal concentrations were higher (p less than 0.01). The concentration of fetal atrial natriuretic peptide before and immediately after blood transfusion (n = 12) rose significantly (p less than 0.05), and the rise correlated positively with the transfusion rate (p less than 0.05). We conclude that atrial natriuretic peptide is present in plasma of the human fetus as early as 21 weeks' gestation and that its concentration increases promptly in response to vascular volume expansion. These findings suggest that atrial natriuretic peptide may play a role in fetal volume homeostasis.

Adolescent↗
PubMed1989

Plasma amino acids in appropriate- and small-for-gestational-age fetuses.

The fetal plasma amino acid profiles of 28 small-for-gestational-age fetuses were established in umbilical venous blood samples obtained by cordocentesis and the values were compared with those of 62 appropriate-for-gestational age fetuses. In the appropriate-for-gestational-age group fetal levels were significantly correlated with but were higher than the maternal levels, which indicates that amino acids are actively transported by the placenta. In the small-for-gestational-age group, the fetal plasma concentration and the fetomaternal ratio of essential amino acids was decreased and this decrease was significantly correlated with the degree of fetal hypoxemia. There was a variable response (e.g., alanine was increased, whereas serine and tyrosine were decreased) involved with nonessential amino acids. In umbilical venous hypoxemia the plasma ratio of nonessential/essential amino acids was increased, and the maternal plasma concentrations of both essential and nonessential amino acids were increased. These findings suggest that in uteroplacental insufficiency there is intrauterine starvation.

Amino Acids↗
PubMed1989

Blood gases, pH, and lactate in appropriate- and small-for-gestational-age fetuses.

The pH, PO2, PCO2, and lactate concentration were measured in umbilical blood samples obtained by cordocentesis from 208 appropriate-for-gestational-age and 196 small-for-gestational-age fetuses at 18 to 38 weeks' gestation. In the appropriate-to-gestational-age fetuses umbilical venous (n = 173) and arterial (n = 35) PO2 and pH decreased, and umbilical venous and arterial PCO2 increased with advancing gestation. Blood lactate concentration did not change. Compared with the appropriate-for-gestational-age fetuses, the small-for-gestational-age fetuses were hypoxemic, hypercapnic, hyperlacticemic, and acidotic. There was mixed respiratory and metabolic acidosis, and the decrease in pH was significantly correlated with both hypercapnia and hyperlacticemia. In the umbilical artery (n = 53) there was a significant linear correlation between the degree of hypoxemia and the degrees of hypercapnia or acidosis. In the umbilical vein (n = 143), the correlations between the degree of hypoxemia and the degrees of hypercapnia, hyperlacticemia, or acidosis were exponential.

Acid-Base Equilibrium↗
PubMed1989

Cordocentesis in the diagnosis of intrauterine starvation.

Glycine and valine were measured in umbilical venous blood obtained by cordocentesis from 28 small-for-gestational-age fetuses. The values were compared with those from 62 appropriate-for-gestational-age fetuses. The ratio of glycine to valine was higher in the small-for-gestational-age fetuses and correlated significantly with the degree of fetal hypoxemia. These findings indicate that placental insufficiency is associated with a biochemical disturbance in the fetus that is similar to that observed in children with protein deprivation and kwashiorkor syndrome.

Blood Specimen Collection↗
PubMed1988

Plasma cortisol and adrenocorticotropin in appropriate and small for gestational age fetuses.

Plasma cortisol and adrenocorticotropin (ACTH) were measured in fetal blood samples obtained by cordocentesis from 61 appropriate for gestational age (AGA) and in 41 small for gestational age (SGA) fetuses at 18-38 weeks gestation. Fetal plasma cortisol (mean 74 nmol/l) did not change but plasma ACTH increased between 18 and 36 weeks gestation and the two were not significantly correlated. Plasma cortisol in cord blood samples after vaginal delivery at term (mean 305 nmol/l) was higher than in samples at elective cesarean section (mean 151 nmol/l), and there was a significant correlation between fetal and maternal levels. The findings suggest that in human fetuses a late gestational rise in plasma cortisol may not be necessary for organ maturation and that the high fetal plasma cortisol in spontaneous labor at term is probably the result rather than the cause of labor. In SGA fetuses, plasma cortisol was higher and ACTH lower than in AGA fetuses, and plasma cortisol was inversely correlated to fetal hypoglycemia, suggesting that in the chronically hypoglycemic SGA fetus the fetal pituitary is under negative inhibition.

Adrenocorticotropic Hormone↗
PubMed1988

Investigation of hypertriglyceridemia in small for gestational age fetuses.

Plasma triglyceride, nonesterified fatty acid (NEFA), glycerol, insulin and blood glucose concentrations were measured in 32 small for gestational age (SGA) and 54 appropriate for gestational age fetuses. Although the values of plasma NEFA and glycerol concentrations were not different in the two groups, some SGA fetuses were hypertriglyceridemic, hypoglycemic and hypoinsulinemic. These findings suggest that hypertriglyceridemia in hypoxemic SGA fetuses is not due to lipolysis, nor to increased triglyceride synthesis, but rather to impaired utilization of circulating triglycerides.

Blood Glucose↗
PubMed1988

Ultra rapid blood sampling for the determination of short-term variations in the circulating concentration of oestradiol in man.

Blood was taken from three healthy female and three healthy male volunteers every 20 s for 15 min. The serum level of oestradiol was measured and the pattern of variation assessed by a cusum plot of the sequential data, by autocorrelation of the detrended serial data, and by looking for pulses. In two cases the variation in oestradiol values was greater than that which could be attributed to variation in the assay. Both these subjects showed a significant overall change in values during the sampling period (an increase and a decrease). There was no trend in the remaining four subjects. In two of the six subjects there was significant autocorrelation of detrended sequential levels. Defining a 'pulse' as three times the assay coefficient of variation no more pulses were identified than was expected from random fluctuations. By frequency analysis the two subjects with significant autocorrelation showed periodic fluctuations of approximately 70/h and 9/h respectively. It is apparent that both the rate of sampling and the method of analysis greatly influence the evaluation of pulsatile release of oestradiol.

Adult↗
PubMedDate not supplied

Assessment of condoms as probe covers for transvaginal sonography.

PURPOSE: This prospective study assessed the incidence of transvaginal probe contamination and breakage of condoms used to cover those probes during transvaginal sonography. METHODS: Over a 9-month period, 214 women underwent transvaginal sonography with probes that had been coated with gel and then covered with a latex condom. Condom defects were detected after the scans by inspection, by adding hydrogen peroxide, and by filling the condoms with 500 ml of water. After the condoms were removed, the probe was either wiped with a dry tissue (during the first 18 weeks of the study) or wiped first with a dry tissue and then with a 70% isopropyl alcohol wipe. Probe head contamination was assessed by periodic swab sampling and culturing for bacteria and herpes simplex virus. Samples of the sonographic gel also were tested for bacterial contamination at approximately weekly intervals. RESULTS: A total of 217 condoms were used, 3 of which broke and were discarded while being applied to the probe. Two of the 214 condoms used (0.9%) were found upon visual inspection to have perforations. None of the other 212 condoms leaked upon being filled with water; none of the 204 condoms tested with hydrogen peroxide showed bubbles. Only 1 of the 46 probe swab samples was positive for bacteria (Acinetobacter species); none of the 26 probe swab samples cultured for viruses or the 25 gel samples cultured for bacteria were positive. CONCLUSIONS: Condoms used to cover transvaginal probes showed a low rate of perforation. Disinfection of the probe with isopropyl alcohol wipes further reduced the risk of contamination.

Adult↗
PubMedDate not supplied

Prenatal diagnosis of trisomy 21 in monozygotic twins with increased nuchal translucency and abnormal serum biochemistry.

We present a case of a monozygotic twin pregnancy who underwent routine screening for chromosomal abnormalities at 14 weeks of gestation by ultrasonographic measurement of nuchal translucency and biochemical analysis of maternal serum alpha fetoprotein and free beta human chorionic gonadotrophin levels. Both screening methods indicated the pregnancy to be at increased risk of Down syndrome, with the ultrasound findings suggesting both fetuses to be affected. An amniocentesis was performed, and karyotype analysis revealed trisomy 21 in both fetuses; the mother subsequently opted for a termination of pregnancy. This case illustrates that screening for trisomy 21 in twin pregnancies is possible by both nuchal translucency measurement and maternal serum markers.

Adult↗