atrial-natriuretic-factor and Asphyxia-Neonatorum

Aldosterone, vasopressin (AVP) and atrial natriuretic factor (ANF) plasmatic concentrations were determined in cord arterial blood from 42 newborns to term: 29 healthful and 13 with perinatal asphyxia. Control group showed plasmatic levels (pg/dl) AVP, aldosterone and ANF significantly lower than perinatal asphyxia newborns group (AVP: 2.27 +/- 1.43 vs 4.26 +/- 2.86; aldosterone: 1.113 +/- 384.79 vs 1,540.38 +/- 595.96; ANF: 2.27 +/- 1.43 vs 4.26 +/- 2.86, respectively (p less than 0.05). We found an inverse correlation between umbilical arterial pH vs AVP, aldosterone and AFN, and a direct correlation between ANF vs aldosterone. Perinatal asphyxia induces secretion of the three studied hormonal factors, likely as a physiologic mechanism of fetal adaptation to hydroelectrolytic and hemodynamic changes which occur during the asphyxia.

Topics: Aldosterone; Asphyxia Neonatorum; Atrial Natriuretic Factor; Female; Fetal Blood; Humans; Infant, Newborn; Pregnancy; Vasopressins

The present study was undertaken to figure out the source of urinary endothelin (ET) and the clinical significance of its possible variations. Urinary ET levels were measured by radioimmunoassay (RIA) in 17 healthy newborns and 20 asphyxiated neonates on days 1, 3, 7 after birth. Plasma ET concentrations of healthy premature infants on day 7 and urinary ET levels in 10 healthy children were also observed at the same time. Results showed that: (1) Urinary ET levels and ET excretion rates were higher than plasma ET in preterm infants on days 7 after birth; (2) Both in preterm and full term infants, urinary ET concentrations fell from the 1st day to the 7th day after birth, ET excretion rates elevated markedly at the end of the 1st week, and they were significantly higher than that of children; (3) Urinary ET levels of asphyxiated group on days 1 and 3 were much higher than those of healthy neonates, and positively correlated with the severity of the illness and urinary NAG. We conclude that: (1) urinary ET mainly comes from the production in renal cells; (2) ET levels in healthy neonatal urine reflect the maturity of kidney; (3) measurement of urinary ET levels in asphyxiated neonates is helpful to judge the degree and to evaluate the prognosis of renal injury.

Topics: Acute Kidney Injury; Asphyxia Neonatorum; Atrial Natriuretic Factor; Biomarkers; Endothelins; Female; Fetal Organ Maturity; Humans; Infant, Newborn; Kidney; Male; Sodium-Potassium-Exchanging ATPase

Guanosine 3',5'-cyclic phosphate (cGMP) is known to be the second messenger of natriuretic peptides and nitric oxide (NO). To investigate the involvement of natriuretic peptides in the regulation of the feto-placental circulation, specific radioimmunoassays were used to measure the concentrations of atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP) and cGMP in the umbilical venous plasma of normal and asphyxiated newborns. The plasma concentrations of ANP, BNP and cGMP in asphyxiated newborns were 48.3 +/- 12.9 pm, 24.5 +/- 9.4 pm and 4.4 +/- 1.6 nM (mean +/- s.e.m., n = 10), respectively. These values were significantly higher than those in the normal newborns (17.4 +/- 1.9 pm, 4.7 +/- 1.0 pm, and 0.78 +/- 0.14 nM, respectively). Moreover, the expression of both ANP-A and ANP-B receptor, biologically active receptors for natriuretic peptides, was detected in term human placenta by Northern bolt analysis. The expression of natriuretic peptide receptors was further confirmed by binding assay using [125I]-labelled ANP and solubilized crude membrane preparations of placental tissue. These findings suggest that cGMP is produced in the placenta, at least partly, by the action of ANP and BNP secreted from fetal heart, in pathophysiological conditions such as fetal hypoxia.

Topics: Asphyxia Neonatorum; Atrial Natriuretic Factor; Base Sequence; Blotting, Northern; Cell Membrane; Cyclic GMP; Humans; Infant, Newborn; Molecular Sequence Data; Natriuretic Peptide, Brain; Nerve Tissue Proteins; Placenta; Receptors, Atrial Natriuretic Factor; Reference Values; Umbilical Veins

The influence of perinatal asphyxia in the secretion of atrial natriuretic factor (ANF) during the first 6 days of life, and its renal consequences are discussed. Comparison between 20 healthy term neonates and 19 with first--or second--degree hypoxic-ischemic encephalopathy (HIE) is made. Daily controls were performed on clinical and neurological examinations and administration of sodium and fluids. On the first and sixth days of life, 24 hours urine collection, natremia, natriuresis, fractionated excretion of sodium and creatinine clearance were determined. The ANF was performed at 1, 2, 3 and 6 days old, by R.I.A. The full term newborns with HIE showed a peak in ANF values on day two, as does the control group, thereafter maintaining higher levels, with a significant difference on day three and six. No correlation could be found between the ANF levels and the renal variables analyzed.

Topics: Asphyxia Neonatorum; Atrial Natriuretic Factor; Brain Damage, Chronic; Humans; Infant, Newborn

Topics: Acetates; Asphyxia Neonatorum; Atrial Natriuretic Factor; Biomedical Research; Central Nervous System Stimulants; Female; Fetal Distress; Humans; Infant, Newborn; Meclofenoxate; Obstetrics; Pregnancy; Research