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Biomedical subjects

D Worthington

Publications and source records attributed to D Worthington.

34 records · Page 2Linked to original sources
PubMed1978

Relation of amniotic fluid lecithin/sphingomyelin ratio and fetal asphyxia to respiratory distress syndrome in premature infants.

In a group of 81 prematurely delivered infants the amniotic fluid lecithin/sphingomyelin ratio was related to functional fetal lung maturity. Intrapartum fetal asphyxia occurred in 33% of the group. An association between fetal asphyxia and the development of respiratory distress syndrome (RDS) in the infant was observed. When pulmonary maturity was borderline according to the amniotic fluid assessment, intrapartum fetal asphyxia was associated with an increased risk for development of RDS in the infant.

Acid-Base Equilibrium↗
PubMed1978

The site of amniocentesis and the lecithin-sphingomyelin ratio.

Simultaneous sampling of amniotic fluid from two sites within the amniotic cavity proximal and distal to the fetal mouth was performed. The lecithin-sphingomyelin (L/S) ratio of amniotic fluid obtained close to the fetal mouth was usually higher than that of amniotic fluid obtained from a site distal to the fetal mouth (20 of 26 cases). Differences of up to 0.7 in the two L/S ratios were measured. This suggested that pooling of amniotic fluid phospholipids occurred and in cases of borderline pulmonary maturity the site of amniocentesis may have influenced the predictive value of the L/S ratio.

Adult↗
PubMed1977

Intrapartum fetal asphyxia: clinical characteristics, diagnosis, and significance in relation to pattern of development.

The clinical and fetal heart rates and acid-base characteristics and their sequelae have been reviewed in 587 patients. The relevant clinical factors in the asphyxia group were the preterm fetus, the intrauterine growth retarded fetus, maternal toxemia, and midforceps delivery. The duration of the developing metabolic acidosis in the asphyxia group ranged from terminal to the last two hours of labor. Marked patterns of total decelerations and moderate and marked patterns of late decelerations are of predictive value in the diagnosis of intrapartum fetal asphyxia with a trend to an increased incidence in the longer duration categories, between four and two hours prior to delivery, and a significant increase in all categories during the last two hours of labor. The significance of intrapartum fetal asphyxia to the newborn infant is evident from the low Apgar scores, increased incidence of moderate and severe respiratory distress syndrome, and central nervous system complications in the asphixia group in relation to the normal group.

Acid-Base Equilibrium↗
PubMed1977

The relationship of cortisol and cortisone to saturated lecithin concentration in ovine amniotic fluid and fetal lung liquid.

Cortisol and cortisone concentrations in ovine amniotic fluid and fetal lung liquid were analyzed with respect to gestational age and fetal lung maturation as reflected by saturated lecithin concentration. In amniotic fluid, the cortisol concentration rises as a function of gestational age while that of cortisone falls (P less than 0.001). The ratio of cortisol/cortisone is significantly related to gestational age (r=0.693, P less than 0.001), and shows an even stronger correlation with saturated lecithin concentration (r=0.832, P less than 0.001). When examined independently of gestational age, the correlation of the cortisol/cortisone ratio to saturated lecithin concentration remains highly significant (r=0.641, P less than 0.001). Similar findings were observed in fetal lung liquid, except that in this fluid both the saturated lecithin concentration and the ratio of cortisol/cortisone are significantly higher than simultaneously determined values in amniotic fluid. These observations provide further evidence that the process of fetal lung maturation is closely linked to the fetal hormonal milieu.

Amniotic Fluid↗
PubMed1977

Human amniotic membrane corticosteroid 11-oxidoreductase activity.

The ability of amniotic membrane, obtained with 3 h of delivery of 28 infants, to interconvert 3H-cortisol and 14-C-cortisone has been examined. The conversion of cortisone to cortisol increases as a function of gestational age, being first seen at 29.5 weeks and reaching values of 50--55% at term (n = 28, r = 0.615, P less than 0.01). Furthermore, a net gain of the active hormone (cortisol) resulting from the bidirectional interconversion of cortisol and cortisone ("C-11 activation index") appears at 31 weeks and reaches 40--50% by term (n = 28, r = 0.674, P less than .001). We speculate that this phenomenon could be an important source of active glucocorticoid for the fetus.

Amnion↗
PubMed1977

Control of adrenocorticotrophin secretion by catecholamines in the pregnant and foetal sheep.

The effect of adrenaline on the maternal and foetal plasma ACTH concentration of twelve pregnant sheep with chronically implanted vascular catheters has been studied. Adrenaline infused into the jugular vein of the ewe or foetus produced carotid arterial adrenaline concentrations of 1-9 ng/ml. The foetal plasma ACTH was 253 +/- 73 pg/ml and it showed a fivefold increase during adrenaline infusion; the ACTH concentration achieved was proportional to the plasma adrenaline. In the ewe plasma ACTH was 99 +/- 23 pg/ml. During adrenaline infusion to the ewe this rose by an amount dependent on the adrenaline concentration achieved and there was also a rise in foetal plasma ACTH but no consistent change in foetal plasma adrenaline. There was no reproducible change in plasma corticosteroid concentration during adrenaline infusion into the foetus but a rise in maternal plasma corticosteroid concentration during infusion into the ewes. Because the adrenaline concentrations achieved during the infusions were within the physiological range, the results indicate that circulating catecholamines may directly or indirectly influence the concentration of ACTH in the circulation. Also, physiological rises in plasma catecholamines in pregnant animals may stimulate the release of ACTH from the foetal pituitary.

Adrenocorticotropic Hormone↗
PubMed1977

Fetal lung maturity. I. Mode of onset of premature labor. Influence of premature rupture of the membranes.

In a prospective study of 133 spontaneous premature deliveries the relation between premature rupture of the membranes (PRM) and development of respiratory distress syndrome (RDS) in newborn infants is examined. PRM is associated with a significantly decreased incidence of RDS in newborn infants (P less than 0.002). This relation is valid at a gestational age of 28 weeks or more and a birthweight greater than 1000 g. Total respiratory morbidity in newborn infants (transient tachypnea + RDS) is also significantly decreased when labor is associated with PRM (P less than 0.005). Assessment of the influences of sex of the infant, fetal asphyxia, and delivery by cesarian section shows that PRM bears a stronger relation than each of these individual factors to a decreased incidence of RDS. Duration of the latent period has no influence on protection from RDS, and it is suggested that fetal lung maturity occurs before the membranes rupture.

Birth Weight↗
PubMed1977

Fetal lung maturation. III. The amniotic fluid cortisol/cortisone ratio in preterm human delivery and the risk of respiratory distress syndrome.

Cortisol and cortisone have been measured in amniotic fluid samples obtained within 24 hours of deliver of 50 premature infants. When expressed as cortisol/cortisone ratios, the ratio tends to rise with advancing gestational age, although statistical significance is not attained. Both cortisol concentration and the cortisol/cortisone ratio are significantly lower in the amniotic fluid of infants who develop respiratory distress syndrome than in those with mature lung function (cortisol ratio: 19.2 +/- 10.3 ng/ml vs 26.1 +/- 9.4, P less than .02; cortisol/cortisone ratio: 1.2 +/- 0.6 vs 2.0 +/- 0.8, P less than .001). These findings also hold in the subgroup of infants less than 32 weeks' gestation but not in those infants at or beyond the 32nd week. The amniotic fluid cortisone concentration is significantly lower in infants born after spontaneous labor beginning with rupture of the membranes as opposed to after contractions or bleeding (13.2 +/- 3.6 ng/ml vs 16.3 +/- 6.1, P less than .05), although the cortisol concentrations and the cortisol/cortisone ratios are not significantly different.

Amniotic Fluid↗
PubMed1976

Fetal heart deceleration patterns in relation to asphyxia and weight-gestational age percentile of the fetus.

The relation between fetal heart rate deceleration patterns and fetal asphyxia and the weight-gestational age percentile characteristics of the fetus has been reviewed from data obtained from 533 patients monitored during the intrapartum period. There is a significant relation between the frequency of total and late decelerations and fetal asphyxia, again confirming this as a useful criterion in the identification of fetal asphyxia. There is a significant relation between decreasing weight-gestational age percentile of the fetus and increasing frequency of total and late decelerations, identifying this fetal characteristic as another variable which will influence fetal heart rate deceleration patterns. The appreciation of the effect of this variable is useful in the interpretation of the fetal heart rate record during the intrapartum period.

Birth Weight↗
PubMed1975

The acid-base and biochemical characteristics of intrapartum fetal asphyxia.

The maternal and fetal acid-base, lactate, and pyruvate characteristics during the course of labor and at delivery were studied in 124 patients delivered of an infant with evidence of metabolic acidosis at delivery. This metabolic acidosis is principally caused by hyperlactatemia resulting from the tissue oxygen debt accompanying fetal asphyxia. Hypoxemia was one mechanism contributing to this fetal asphyxia and tissue oxygen debt. This evidence of fetal asphyxia developed during the last half and principally during the last two hours of the intrapartum period. Acid-base assessment of fetal blood with identification of a metabolic acidosis will provide an accurate objective diagnosis of intrapartum fetal asphyxia.

Acid-Base Equilibrium↗
PubMed1975

Clinical characteristics of pregnancies complicated by intrapartum fetal asphyxia.

The clinical characteristics of 124 pregnancies complicated by intrapartum fetal asphyxia have been reviewed. The evidence of fetal asphyxia tends to appear earlier in patients with maternal medical and obstetric complications than in those with labor complications. Evidence of clinical fetal distress was present in 36 per cent and was not related to the severity of the asphyxia. Low Apgar scores occurred in 40 per cent of infants with moderate asphyxia and in 80 per cent of infants with severe asphyxia at delivery. In the newborn infants, clinical evidence of cerebral abnormality was observed in 3 per cent, and evidence of the respiratory distress syndrome was seen in 3 per cent of the study group.

Acidosis↗
PubMed1975

The incidence of fetal asphyxia in six hundred high-risk monitored pregnancies.

Six hundred high-risk monitored obstetric patients were reviewed for evidence of fetal asphyxia at delivery. The over-all incidence was 20 per cent, i.e., 8 times the incidence in a normal obstetric population. Highly significant indicators of risk for asphyxia were severe toxemia (79 per cent), prematurity with further medical or obstetric complications (36 per cent), and clinical fetal distress, particularly meconium staining with fetal heart rate abnormality (33 per cent). All obstetric, medical, or gestational complications in this review were associated with an increased risk for fetal asphyxia when compared to that in a normal obstetric population.

Asphyxia Neonatorum↗
PubMed1975

The clearance of ACTH from the plasma of adult and fetal sheep.

The disappearance of 125-I-ACTH from the circulation of 4 pregnant and fetal sheep has been followed after a single injection to the ewe or fetus. The mean metabolic clearance rate for the fetus and the ewe was 55 and 34 ml/min/kg respectively, giving a half-life in each case of about 1 min. The higher fetal than maternal arterial plasma ACTH concentration has been ascribed to a higher rate of secretion rather than a reduced rate of clearance compared with the ewe. There was no evidence of placental transfer of immunologically reactive ACTH.

Adrenocorticotropic Hormone↗
PubMedDate not supplied

The assessment of subclinical ifosfamide-induced renal tubular toxicity using urinary excretion of retinol-binding protein.

The excretion of retinol-binding protein in early morning urine samples, expressed as a ratio to urinary creatinine (RBPCR), was used as a measure of proximal renal tubular toxicity in children during or after treatment with ifosfamide-containing chemotherapy. The results showed a progressive increase in renal tubular leak after exposure to ifosfamide that persisted after treatment. The toxic effect appeared to be greatest in younger children and at least partly dose-dependent, although partially reversible after each course of chemotherapy. However, few patients had related symptoms and none experienced major metabolic difficulty. RBPCR appears to offer a sensitive and noninvasive way of monitoring sequential change in renal tubular function after exposure to ifosfamide. Further studies are required to define more clearly the effect of cumulative dose, age, and drug scheduling and to identify whether a level of renal tubular dysfunction, measured by RBPCR or a similar noninvasive technique, can identify a threshold beyond which further exposure to ifosfamide is likely to be significantly and permanently damaging.

Age Factors↗