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T Stefos

Publications and source records attributed to T Stefos.

36 records · Page 2Linked to original sources
PubMed1990

Flow velocity waveforms of the vascular system in the anemic fetus before and after intravascular transfusion for severe red blood cell alloimmunization.

Sixteen intravascular transfusions were performed in 16 anemic human fetuses. To investigate the status of the vascular system with Doppler ultrasonography before and after correction of anemia, pulsatility index values were obtained for the flow velocity waveforms of the middle cerebral artery, internal carotid artery, anterior cerebral artery, thoracic aorta, abdominal aorta, renal artery, femoral artery, and umbilical artery before and the day after the correction of anemia. The fetuses were divided into two groups: (1) fetuses with a hematocrit level between 2 and 4 SDs below the normal mean value for gestational age and (2) fetuses with a hematocrit value less than 4 SDs below the normal mean value for gestational age. No significant differences were observed in the pulsatility index values of the vessels studied before and after correction of anemia in both groups of fetuses. These data suggest that the pulsatility index cannot be used as an indicator of fetal anemia at the hematocrit values studied.

Anemia, Hemolytic, Autoimmune↗
PubMed1989

Individual growth curve standards for fetal head and abdominal circumferences: effect of the type of measurement on growth prediction.

Head and abdominal circumferences (HC, AC) can be measured directly or estimated from diameters. Accurate prediction of circumference growth after 26 weeks depends on growth model specification and the quality of the circumference measurement method used. To evaluate the effect of the method of measurement, direct and estimated HC and AC values from 20 normal fetuses, obtained between 15 and 38 weeks, were used to determine two pairs of functions for specifying HC and AC growth models. The two HC and AC data sets and pairs of model specification functions were used in various combinations to determine HC and AC growth models, to predict growth after 26 weeks, and to compare predicted values to actual measurements. Systematic and random prediction errors were determined for each combination. For HC no differences in either type of error were found. Similar results were obtained for AC with one exception, a statistically significant difference in systematic error between the directly measured circumferences - model specification based on estimated values combination and the estimated circumferences - model specification based on directly measured values combination. These results indicate that the prediction of future HC and AC growth is not significantly affected by the type of circumference measurement procedure used except in extreme cases where circumference measurements are made on parts of the body that can be easily distorted.

Abdomen↗
PubMed1989

Influence of the interval between time points on individual fetal growth curve standards derived from Rossavik models and two ultrasound scans before 26 weeks, menstrual age.

We studied the influence of the interval between the two scans used before 26 weeks' menstrual age to generate individual fetal growth curve standards utilizing the Rossavik growth model: P = c(t) kappa + s(t) (model specification functions previously reported). Intervals of 3 weeks to 12 weeks were suitable for predicting the growth of the abdominal and head circumferences and femur diaphysis length in individual fetuses. However, large systematic and random errors were found with intervals less than 5 weeks for three-dimensional parameters such as the head and abdominal cubes and estimated fetal weight. In addition, the data suggest that the systematic errors for these latter parameters may increase with intervals of 10 weeks or more. Overall, optimal individual fetal growth curve standards were best generated from two scans before 26 weeks' menstrual age separated by 5 weeks to 9 weeks.

Anthropometry↗
PubMed1989

Effect of timing of initial scan and interval between scans on Rossavik growth model specification.

The effect of the time of the initial scan and the interval between the two scans needed for Rossavik growth model specification was evaluated in 20 normally growing fetuses. Based on systematic and random prediction errors, determined by comparing predicted values to measured values obtained after 27 weeks, menstrual age, optimal results for all parameters studied were obtained with an initial scan at 18 weeks and an interval of 6 weeks between scans. For one-dimensional parameters--head circumference (HC), abdominal circumference (AC), and femur diaphysis length (FDL)--similar results were obtained with an initial scan at 15 weeks and an interval of 3 weeks, but systematic overestimations were seen with 9-week intervals for HC. Studies with three-dimensional parameters--head cube, abdominal cube, and estimated weight--indicated that the timing of the initial scan was not critical, although less variability was seen with the initial scan at 18 weeks. However, the use of 3-week and 9-week intervals (instead of 6 weeks) produced significant systematic errors that varied with the parameter studied. These results suggest that Rossavik growth model specification is possible under a variety of conditions, but both the timing of the initial scan and the interval between scans must considered for each parameter.

Embryonic and Fetal Development↗
PubMed1989

Individual growth curve standards in twins: prediction of third-trimester growth and birth characteristics.

The ability of Rossavik growth models, determined from measurements obtained before 24 weeks, to predict third-trimester growth and birth characteristics in normally growing twins has been investigated. Third-trimester values for head circumference, abdominal circumference, and femur diaphysis length were predicted with an accuracy of +/- 6% to 9% (95% to 98% of percent deviations). For thigh circumference and estimated weight, the comparable values were +/- 15% and +/- 16%, respectively. The head circumference at birth was predicted without bias; the random error was approximately +/- 5% (94% of percent differences). Weight, abdominal circumference, and thigh circumference were systematically overestimated (3.1%, 14.9%, and 11.3%, respectively) as a result of differences in prenatal and postnatal measurement procedures. After correction for systematic errors, these parameters could be predicted with random errors of -11.5% to 7.2% (weight), -12.8% to 5.4% (abdominal circumference), and -15.3% to 10.0% (thigh circumference). Growth Potential Realization Index values were found to have means of approximately 100% and ranges from 91% to 118%. These results are similar to those for singletons and indicate that individual assessment of growth in twins can be carried out with the same methods used for singletons.

Adult↗
PubMed1983

The relationship of tar content to decline in pulmonary function in cigarette smokers.

The impact of the tar content of cigarettes on pulmonary function was examined in 1,355 men. These men represented 383 current cigarette smokers, 555 former cigarette smokers, and 417 never smokers enrolled in longitudinal study of aging. Current smokers' cigarette exposure was estimated by the number of cigarettes smoked per day and tar content per cigarette. spirometry was performed twice on all subjects at a 5-yr interval. A multiple regression analysis indicated that tar content did not significantly influence baseline levels of forced vital capacity (FVC) or forced expiratory volume in one second (FEV1), after controlling for age, height, and number of cigarettes smoked. Similarly, tar content did not significantly influence follow-up levels of FVC or FEV1, after controlling for age, height, number of cigarettes, and baseline pulmonary function. These data suggest that low tar cigarettes may not protect smokers from an increased rate of decline in pulmonary function.

Adult↗
PubMed1983

Relationships between serum prolactin levels and follicle stimulating hormone response to luteinizing hormone-releasing hormone during early puerperium.

The effect of serum prolactin (Prl) levels on pituitary response to iv luteinizing hormone-releasing hormone (LRH) (100 micrograms) was studied in 23 normal puerperal women on day 1 post-partum. All women had an uneventful full-term pregnancy and delivery. The LRH test was repeated in 8 of the women on day 3 and in the remaining 15 on day 6 post-partum. Serum Prl levels were high on days 1 and 3, but decreased significantly on day 6 (P less than 0.01). No pituitary FSH response to LRH stimulus was found on day 1 post-partum in all 23 women. In those who were given placebo, FSH levels in serum did not change in response to LRH on day 3 (4 women), but increased significantly on day 6 (5 women) in all subjects (P less than 0.05). Conversely, when oral metoclopramide was given from day 1 to 6 (10 women) the responsiveness of FSH to LRH on day 6, found in the placebo group, was not observed. Early reduction of serum Prl values on day 3 post-partum by bromocriptine treatment from day 1 to 3 (4 women) did not accelerate the FSH response to LRH. These results suggest an inhibitory effect of elevated serum Prl on the pituitary FSH response to LRH in women during early puerperium.

Adult↗
PubMedDate not supplied

Birth characteristics of 5,278 pregnancies.

Several characteristics of newborns were investigated in our population from northwestern Greece, for the first time during the last 30 years, providing useful data. The study included 5,278 pregnant women who delivered from 1992-1996, and the following parameters have been studied: (1) age of pregnancy at the parturition, (2) weight of newborn, (3) weight of placenta, (4) age of the pregnant woman, and (5) length of the umbilical cord, all five in relation with parity. Statistically significant relationships were found between: (1) age of the pregnant woman and the parity (but not between paras-2 and paras-3), (2) weight of the newborns between primiparas, paras-3, and paras-4 as also paras-2 and paras-4, (3) length of the umbilical cord between primiparas and paras-3 and paras-4. No significant relationship was found between placenta weight and parity, nor between gestational age at the parturition and parity. The study gives these features for the first time, to our best knowledge, of the birth characteristics of a certain and very homogeneous population of northwestern Greece, and these useful data could be the basis for future studies and comparisons with other populations.

Adolescent↗
PubMedDate not supplied

Folate status during labor: relationship with pregnancy outcome.

OBJECTIVE: The purpose of our study was to determine the folate status of pregnant women at labor, and to detect probable relationships with the gestational age at delivery, the birth weight of the newborns, as well as the mode of the delivery, taking into account any changes in the fetal heart rate (FHR) at labor and, subsequently, operative delivery. METHODS: Maternal serum folate levels were determined using automated fluorometric enzyme-linked assays. Gestational age was determined by ultrasound in the first trimester followed by serial fetal biometry. RESULTS: The results of our study in 101 consecutive pregnant women revealed that the mean (+/-SD) maternal serum concentration of the folate during labor was 12.01 (+/-4.16) ng/ml (range 2.50-23). The mean (+/-SD) gestational age at labor was 38.5 (+/-1.2) weeks (range 35-41 wks) as also the mean (+/-SD) birth weight of the newborns was 3.217 (+/-403) g (range 2,000-4,250 g). CONCLUSIONS: No significant correlation (p>0.05) between folate levels of the maternal serum and gestational age at delivery or birth weight was found. The mode of delivery as a result of probable relationship between operative delivery and maternal serum folate levels was also not found.

Adolescent↗
PubMedDate not supplied

Routine obstetrical ultrasound at 18-22 weeks: our experience on 7,236 fetuses.

OBJECTIVE: This study aimed at examining the detection rate of congenital abnormalities by using routine ultrasonography at 18-22 weeks of gestation. METHODS: The sample included 7,236 fetuses. A detailed sonographic examination was performed in each fetus and a neonatal evaluation or pathology examination was made to confirm the prenatal findings. RESULTS: The total prevalence of fetal abnormalities in our sample was 2.24% (162/7,236). There were 29/162 (17.9%) fetuses with CNS abnormalities, 27/162 (16.7%) fetuses with gastrointestinal abnormalities, and 28/162 (17.3%) fetuses with urinary tract abnormalities. There were also 31/162 (19.1%) fetuses with cardiovascular abnormalities, 26/162 (16.0%) with malformation of the limbs and musculoskeletal system, and 21/162 (13%) fetuses with other various abnormalities. The overall sensitivity in detecting fetuses with congenital abnormalities was 80.25% (130/162). The sensitivity per system was 93.1% (27/29) for CNS, 45.2% (14/31) for cardiovascular system, 85.2% (23/27) for gastrointestinal system, 85.7% (24/28) for urinary system, 84.6% (22/26) for musculoskeletal system, and 95.2% (20/21) for the rest of the abnormalities detected. We performed 40 pregnancy terminations in the group of malformed fetuses. Among the fetuses considered as normal, 1.7% had chromosomal abnormalities. CONCLUSIONS: The results indicate that routine sonographic examination at 18-22 weeks of gestation can detect the majority of congenital abnormalities. More experience is needed for the examination of the cardiovascular system, where the sensitivity was particularly low (14/31 or 45.2%).

Central Nervous System↗
PubMedDate not supplied

Evaluation of fetal growth by ultrasonography in twin pregnancy: a comparison between individual and cross-sectional growth curve standards.

Cross sectional curves and individual fetal growth curves standards from the Rossavik growth model [P = c(t)(k + s(t]] were generated for abdominal and head circumferences, femur diaphysis length and estimated fetal weight from a sample of 59 women with twin pregnancy. These curves were compared to their counterparts in singleton pregnancies. Cross sectional curves of the four fetal anatomic parameters under study fell progressively below the curves for singletons during the last trimester of gestation. In contrast, there were few differences between individual fetal groWth curve standards for twin and singleton pregnancies. In 11 of the 59 patients, both methods were used to evaluate fetal growth in the last trimester of gestation. In 5 of these patients, fetal growth was normal by both methods in all 10 fetuses. In the 6 other patients, there were 3 fetuses with abormal estimated fetal weights (EFWs) by both population and individual standards. However, 3 fetuses had abnormal EFW's by populations standards but not by individual standards while the EFW of another fetus was abnormal by individual standards but not by population standards. These results illustrate that the cross-sectional approach to the assessment of growth in twins can be misleading and may lead to incorrect conclusions concerning the growth of these fetuses.

Embryonic and Fetal Development↗
PubMedDate not supplied

Individual growth curve standards in twins: growth in the second trimester.

To provide a more detailed assessment of the growth of twins, the individual second trimester growth patterns of six fetal parameters [HC, AC, FDL, ThC, head cube (A) and abdominal cube (B)] were studied in fourteen sets of normal twins (six monozygotic and eight dizygotic) and sixteen normal singletons using the Rossavik growth model [P = c(t)(k + s(t)]. Comparisons of start points and coefficient c values indicated no statistically significant differences in the growth processes of twins and singletons in early pregnancy and no detectable effect of zygocity. Comparisons of second trimester growth within sets of twins and randomly paired singletons revealed the presence of differences in feto-placental support. A significant effect of differences in genetic growth potential or maternal support could not be demonstrated, however. These results suggest that with respect to growth, normal twins in the second trimester can be treated as two singletons in the same mother.

Embryonic and Fetal Development↗
PubMedDate not supplied

Detection of intrauterine growth retardation in twins using individualized growth assessment: I. Evaluation of growth outcome at birth.

The growth of 17 sets of twins was evaluated at 2 to 3 week intervals from 15 weeks to delivery by measurement of the head circumference, abdominal circumference, and thigh circumference, and estimation of weight. The birth characteristics of these twins were compared to those predicted by Rossavik growth models, derived from second-trimester ultrasound measurements, using the Growth Potential Realization Index (GPRI) and by comparison to population standards. Newborns were classified as normal or intrauterine growth retarded (IUGR) based on their Neonatal Growth Assessment Score, determined from GPRI values. All normal twins had birth weights that were appropriate-for-gestational-age and had few abnormal birth measurements. The birth weight differences between normal twin fetuses were all < 20%. IUGR twins were both small for gestational age (78%) and appropriate-for-gestational-age (22%), and all had 3 or 4 abnormal GPRI values. In only 40% of the cases was the birth-weight difference between a normal and an IUGR twin > 20%. No single anatomic parameter evaluated at birth adequately separated the normal twins from those with IUGR. These results indicate the need for multiple parameter Individualized Growth Assessment in the detection of IUGR in twins.

Adult↗
PubMedDate not supplied

Detection of intrauterine growth retardation in twins using individualized growth assessment. II. Evaluation of third-trimester growth and prediction of growth outcome at birth.

Second- and third-trimester growth in 34 twin fetuses was evaluated with ultrasonography by measurement of five anatomic parameters. Rossavik growth models, derived from second-trimester measurements, were used to specify expected third-trimester growth curves. Actual measurements were compared to predicted measurements by calculation of the percent deviations. Growth outcome at birth [normal, intrauterine growth retardation (IUGR)] was determined from Neonatal Growth Assessment Scores. Growth in the second trimester was similar in normal and IUGR twins. In the third trimester, abnormal negative deviations were larger and more numerous in IUGR twins. However, there was considerable individual variability and normal twins also had abnormal negative deviations. In IUGR twins, the first appearance of an abnormal negative deviation was quite variable (range: 28.6 weeks to 35.1 weeks), as was the parameter to show such a deviation. Prediction of neonatal outcome was poor using individual anatomic parameters but improved considerably with use of all five parameters. However, some fetuses were misclassified when only the number of abnormal negative deviations was used. The Prenatal Growth Assessment Score (PGAS), determined by both the number and magnitude of abnormal negative deviations, predicted neonatal outcomes with a sensitivity of 100% and specificity of 100%. On average, PGAS values were abnormal 5 weeks before delivery. These results indicate that normal and IUGR twins can be separated, using third-trimester growth patterns, if multiple parameter Individualized Fetal Growth Assessment is employed.

Diseases in Twins↗
PubMedDate not supplied

A case of fetal intestinal tract distensions: prenatal biochemical and ultrasound evaluation.

Fetal intestinal tract abnormalities can be pregnancy complications at all maternal ages. There have been reports of ultrasound identification of these abnormalities, particularly of fetal intestinal obstructions. We report the first case to our knowledge of elevated levels of the intestinal isozyme, alkaline phosphatase, in the amniotic fluid and blood serum and also the presence of prealbumin in the amniotic fluid of a fetus with extensive intestinal distension and polyhydramnios. It was revealed that the alkaline phosphatase intestinal isozyme as well as protein electrophoresis for abnormal albumin bands in the amniotic fluid are valuable markers for the early diagnosis of the above-mentioned fetal abnormalities.

Abnormalities, Multiple↗
PubMedDate not supplied

Rapid fetal hemoglobin estimation assay during cordocentesis.

A method for rapid estimation of fetal blood content during cordocentesis is described. This procedure gives an opportunity to determine the contamination of the fetal sample by maternal blood as soon as possible. The method is based on the ability of fetal hemoglobin to resist denaturation in alkaline conditions, and can be used routinely. Fetal blood samples show a lower degradation rate (range 1.2-8.2%) compared to the maternal samples (range 25.0-52.5%). The method has the capacity to discriminate fetal and maternal samples with regard to their fetal hemoglobin content.

Cordocentesis↗
PubMedDate not supplied

Clinical significance of creatine kinase isoenzymes for fetal asphyxia in women at labor.

Creatine kinase-brain isoenzyme activity (CK-BB) was measured longitudinally in the serum of 31 pregnant women in the first stage of labor (early and advanced), at delivery, and 1, 6 and 24 h after delivery, in the umbilical cord and in the serum of their neonates on the first day of life. There was no increase in serum CK-BB values of mothers that delivered normally (n = 15) or had an elective cesarean section (n = 5). Pregnant women with signs of fetal distress had an increase in CK-BB levels in the first stage of labor (mean +/- SD 4.5 +/- 4.9 U/l, p < 0.03) and 6 h after delivery (12 +/- 4 U/l, p < 0.0001). Neonates with intrauterine stress also had an increase in their CK-BB to 144 +/- 116 U/l at 6 h of life, in comparison with babies born without signs of stress. It appears that CK-BB during labor and in the first hours of life may be indicative of intrauterine stress.

Asphyxia Neonatorum↗