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Biomedical subjects

H Bard

Publications and source records attributed to H Bard.

At least 73 records · Page 4Linked to original sources
PubMed1983

The importance of an antenatal ultrasonographic diagnosis of correctable fetal malformations.

This study describes the importance of an early echographic examination during pregnancy for the antenatal diagnosis of fetal anomalies potentially correctable after birth. During a period of 18 months there were 28 cases. In seven fetuses a gastrointestinal malformation was diagnosed between 20 and 36 weeks of gestation; there were 16 cases of urogenital anomalies detected between 19 and 38 weeks of gestation, and five other various malformations were detected between 17 and 33 weeks of gestation (two diaphragmatic hernias, one congenital heart malformation, and two cases of benign tumors). This study suggests that ultrasonic antenatal diagnosis could result in a decrease in the morbidity of congenital malformations that are correctable if the delivery is carried out in a high-risk perinatal center.

Congenital Abnormalities↗
PubMed1983

Changes in the systolic time intervals of the fetal heart after surgical manipulation of the fetus.

The fetal cardiac systolic time intervals are potentially an important indicator of fetal well-being. Because experimental studies with the use of animal models are being carried out to evaluate the effects of abnormal antenatal factors on fetal myocardial function, it is important to establish the changes in the systolic time intervals that can occur as a result of the surgical preparation of the animal model and also to determine the time required for the recovery of myocardial function. After the appropriate catheters have been placed in fetal sheep, the ratio of preejection time to ejection time was followed in six maternal-fetal sheep models for 3 days postoperatively. The mean values obtained from the animals were then compared to the data obtained and were considered to be normal on the eighth postoperative day. In spite of acid-base data within the physiologic limits, the ratio of preejection period/ejection time was elevated postoperatively and reached normal values between 2 to 3 days postoperatively. The study demonstrates that 3 days are required for the recovery of fetal myocardial function before baseline preexperimental conditions are reached.

Animals↗
PubMed1983

A comparison of blood viscosity between the adult sheep and newborn lamb. The role of plasma and red blood cell type.

Adult sheep and newborn lamb blood viscosity (Vc) have been compared by taking into account not only the hematocrit, but also the type of the red cells (adult or fetal) in the circulation and the plasma Vc. At all shear rates studied the whole blood Vc of the adult was higher than that of the newborn. Plasma Vc was 1.58 +/- 0.18 centipoises in the adult compared to 1.21 +/- 0.19 in the newborn group (P less than 0.001). The mean relative apparent viscosity (whole blood Vc/plasma Vc) was higher in the newborn although the difference was not significant.

Animals↗
PubMed1983

The effect of high or low oxygen affinity red cells on tissue oxygenation and myocardial function in hypoxic newborn lambs with or without hypercapnia.

In order to compare high and low oxygen affinity blood under conditions of severe respiratory failure, the effects of a high or low P50 were evaluated in two groups of newborn lambs (P50, 20 mmHg versus 30 mmHg), under conditions of hypoxic hypoxia (Fio2, 10%) and hypercapnic hypoxia (Fio2, 10% and Fico2, 10%). Data on cardiovascular function, blood gas parameters, and tissue oxygenation were collected under normoxic conditions and during severe hypoxia. During hypoxic hypoxia, a higher arterial oxygen content was noted in the high affinity group throughout the experiment; however, there were no significant differences detected in the remainder of the parameters studied. During hypercapnic hypoxia, the position of the oxygen dissociation curve did not cause any significant differences. When, however, hypercapnic hypoxia was compared to hypoxic hypoxia, there was a significant increase in cardiac output and myocardial contraction during hypercapnia.

Animals↗
PubMed1982

Blood viscosity during the neonatal period: the role of plasma and red blood cell type.

Adult and newborn infant blood viscosity have been compared, taking into account not only the hematocrit, but also the type of red blood cells (fetal or adult) in the circulation and the plasma viscosity. At all shear rates studied, the viscosity of the adults' blood was higher than that of the newborn infant. At shear rates of 11.5 and 46 second-1, an increase in the hematocrit influences the viscosity of neonatal and adult blood similarly. At 115 and 230 second-1, the rise in hematocrit was associated with a greater increase in viscosity in the presence of fetal red blood cells, probably because of their lesser deformability. Plasma viscosity was 1.18 +/- 0.17 centipoises in the newborn compared to 1.36 +/- 0.10 in the adult group (P less than 0.001). The relative apparent viscosity (apparent viscosity/plasma viscosity) was higher in the neonate at a hematocrit of 65% (P less than 0.05). In normal conditions, blood viscosity is lower in the neonatal period because of a lower plasma viscosity.

Adult↗
PubMed1982

Characterization of specific steroid binding in human amnion at term.

In human fetal membranes (amnion and chorion) the appearance, during the last few weeks of pregnancy, of a protein which binds progesterone has been suggested as playing an important role in the inset of labor. The purpose of the present study was to quantitatively characterize specific binding in fetal membranes. Amnion, rather than chorion, was studied because it could be obtained free from contamination by other tissues. The cytosol (105,000 X g supernatant) was used after being extracted for 1 h with dextran-coated charcoal. The specific binding of cortisol in the cytosol, determined with a charcoal assay, was stable after storage at -20 degrees C or -60 degrees C and after heating for 1 h at 37 degrees C. It was reversible, and showed high-affinity, KD = 1 +/- 0.5 nM (mean +/- SEM, n = 6) and a large number of sites were found, 1497 +/- 666 fmoles/mg protein (mean +/- SEM, n = 6). In contrast, progesterone binding in the cytosol had a 10-fold lower affinity, KD = 12 +/- 5 nM (mean +/- SEM, n = 5) with 802 +/- 246 fmol bound/mg protein (mean +/- SEM, n = 5). A number of steroids were examined for their ability to compete with cortisol binding. The following were found to express affinities relative to cortisol which was considered to be 100: corticosterone (100), progesterone (10), cortisone (8), 5 alpha-pregnane-3, 20-dione (2), and 20 alpha-hydroxy-4-pregnen-3-one (less than 1). No competition was found for dexamethasone, betamethasone, triamcinolone, triamcinolone acetonide, R5020, medroxyprogesterone acetate, estrone or estradiol. These studies indicate that the steroid binding protein associated with human amnion at term exhibits a higher affinity for a cortisol and corticosterone than progesterone. Thus it is perhaps involved in the metabolism of glucocorticoids by the membranes, rather than in the local withdrawal of progesterone, as proposed by previous investigators.

Amnion↗
PubMed1982

Early discharge of low birthweight infants.

A study was conducted to see if the discharge weight of preterm infants born at less than or equal to 2000 g could safely be reduced. A study group (21 infants) was discharged 'early' at a mean weight of 2010 g (1890-2190) provided there were no medical problems, weight gain was adequate, temperature control in room air was stable, all feedings were by breast, and the mother was ready to have the baby home. A control group (17 infants) was discharged at a mean weight of 2261 g (2200-2400). The duration of time in hospital for the 'early' group was shortened by 11.6 days. At expected date of delivery the weight of infants in each group was similar (3095 +/- 403 compared with 3146 +/- 453 g); length, head circumference, and haemoglobin concentration in each group were similar too. There was no morbidity or mortality in either group. Early discharge did not affect mothering confidence. This study shows that low birthweight infants can be discharged early (at 2000 +/- 100 g) provided appropriate criteria are met, home conditions are adequate, and follow-up is available.

Female↗
PubMed1982

Postnatal fetal and adult hemoglobin synthesis is preterm infants whose birth weight was less than 1,000 grams.

To determine if environmental factors could effect the switchover from fetal hemoglobin (HbF) to adult hemoglobin (HbA) synthesis, studies were carried out on blood samples from eight infants born at less than 1,000 g, when they had reached their postconceptional age corresponding to term. All of these infants required prolonged intensive care, multiple blood transfusions, and two required exchange transfusions. Several were ventilated mechanically for 60 d and two infants had bronchopulmonary dysplasia at the time of the study. The blood samples were incubated in an amino acid mixture containing [14C]leucine followed by column chromatography on DEAE Sephadex for separation of radioactive HbA and HbF. In spite of the extreme prematurity and poor growth of these sick infants, the proportional synthesis of HbF and HbA, as determined by the incorporation of [14C]leucine during the erythrocyte incubations, was characteristic of the period of human development from which the erythrocytes were obtained.

Blood Transfusion↗
PubMed1982

Subsequent pregnancy following the loss of an early preterm newborn infant weighing less than 1000 grams.

During a 5-year period (1974 to 1978), 84 mothers with an average age of 26.3 +/- 4.5 years delivered 89 newborn infants who subsequently died. Each infant weighed less than 1000 g. These infants had a mean birth weight of 790 +/- 170 g and a mean gestational age of 26.3 +/- 1.9 weeks. Thirty-six (90%) of 40 mothers who subsequently became pregnant gave birth to a surviving newborn. The mean gestation age and birth weight were 37.6 +/- 3 weeks and 2754 +/- 754 g, respectively. Similar data were obtained from a control group of 565 mothers who delivered normal infants at term during a 2-month interval within the study period. In the control group 170 mothers subsequently became pregnant and 163 (96%) gave birth to normal infants at term. Mean gestational age was 39.09 +/- 2 weeks (P less than .001) and birth weight was 3304 +/- 566 g (p less than .001).

Adult↗
PubMed1981

Effect of fetal or adult red cells on tissue oxygenation and myocardial function in normoxemic newborn lambs.

Twelve newborn lambs less than 48 hr old had their high oxygen affinity blood exchanged for low-affinity fresh adult blood. Tissue oxygenation, hemodynamic status, blood gases, and myocardial function were compared before and after the exchange transfusion. The P50 was increased from 18 to 29 mm Hg after exchange transfusion; pH and hemoglobin levels remained constant; and there was no change in myocardial function, arteriovenous O2 content difference, O2 consumption, or cardiac output. However, mixed venous PO2 was significantly increased with low affinity red cells (33 versus 23 mm Hg).

Animals↗
PubMed1981

Oxygenation in anemic newborn lambs with high or low oxygen affinity red cells.

Experiments to determine the effect of the oxygen-hemoglobin dissociation curve on oxygen delivery during neonatal anemia, were carried out on 15 sedated and ventilated lambs less than 48 hr of age. Eight of the animals were exchange transfused with adult blood. The P50 of the exchange transfused group was 32.1 mm Hg (low O2 affinity) compared to 19.4 mm Hg for the controls (high O2 affinity). The animals were made anemic by isovolumic exchange transfusions with plasma. At different levels of hemoglobulin defined as mild (8 mg/100 ml), moderate (6 mg/100 ml), and severe (4 mg/100 ml) anemia, tissue oxygenation, hemodynamic status, and blood gases were compared. Mixed venous PO2 was significantly lower in the high affinity group throughout this study. Cardiac output was significantly greater in the low affinity group during severe anemia. Oxygen consumption remained stable in the low affinity group, but decreased significantly in the high affinity group when the anemia was severe. The data indicate that during severe anemia, blood with a high P50 is more capable of adequately oxygenating tissues than that with a low P50.

Anemia, Neonatal↗
PubMed1980

Neonatal necrotizing enterocolitis: the relation of age at the time of onset to prognosis.

A study was undertaken to evaluate the predisposing factors, age at the time of onset and prognosis of neonatal necrotizing enterocolitis in 62 patients treated in a neonatal intensive care unit during a 5-year period (1974-78). Because of a peak frequency during the first week of life, the cases were divided into those of early-onset illness (appearing within the first week of life) and those of late-onset illness (appearing after this week). The main differences between the two groups were in the age at the time of the first enteric feeding (1.6 +/- 0.9 d v. 40 +/- 2.4 d [mean +/- one standard deviation]; P less than 0.001) and the interval between this feeding and the onset of symptoms (3.0 +/- 1.5 d v. 10.6 +/- 6.0 d; P less than 0.01). Furthermore, the early-onset illness was more severe, more often necessitating surgical intervention and carrying a higher mortality, than the late-onset illness. Thus, this study demonstrates that there are two forms of neonatal necrotizing enterocolitis, differing in time of appearance after birth as well as in severity and prognosis.

Age Factors↗