First Week Of Extrauterine Life Research Articles

Reference intervals for brain natriuretic peptide in healthy newborns and infants measured with an automated immunoassay platform

In order to assess the reference intervals for B-type natriuretic hormone (BNP) in the first days of life, we measured peptide concentrations using the fully automated Access platform. Plasma BNP was measured in 188 apparently healthy newborns and infants throughout the first month of extra-uterine life, as well as in 245 healthy infants ranging from 1 month to 12 years of age. BNP showed the highest concentrations in the first 2 days of life, with a progressive decline afterwards. Moreover, BNP values in the first week of life were significantly higher (p<0.0001) than values observed in the next periods. As a result, a significant negative correlation was found between BNP and age values when considering all 433 samples (rho=-0.816, p<0.0001 by the Spearman rank correlation test). There was no significant difference between BNP values found in males and females. According to this data, our study indicates that at least two reference intervals should be used for newborns and infants. The first, with higher BNP values for neonates in the first week of extra-uterine life, and the other, with lower BNP values for infants aged 2 weeks to 12 years.

Electrical brain activity in preterm infants at risk for intracranial hemorrhage.

We studied the effect of preterm birth on electroencephalographic background activity in 20 infants < 32 weeks' gestation. Six infants developed periventricular-intraventricular hemorrhage during the study period. Four-channel 24-h cassette recordings were obtained on day 1, 3-5 and 7-9. For each of the 24-h recordings, the percentage of the time showing stage I (continuous activity), stage II (mixed activity) and stage III (discontinuous activity) epochs was calculated. In infants without periventricular-intraventricular hemorrhage, a positive linear relationship between gestational age and continuous activity and a negative linear relationship between gestational age and discontinuous activity existed in the first day recordings; in infants with periventricular-intraventricular hemorrhage, such relationships were not found. To determine if the changes in continuous and discontinuous activities during the first week of extrauterine life were different from the expected changes during a corresponding time in utero, we calculated the expected amounts of stage I and III changes for each infant. The actual changes were not significantly different from the expected values in both study groups. However, during the onset and/or extension of periventricular-intraventricular hemorrhage, depression of the electroencephalographic background activity was found.

Sex differential patterns in perinatal deaths in Italy.

In industrialized countries, male excess is generally found in early deaths, despite the overall decrease in mortality. We studied the association between sex and some factors generally considered crucial for babies' survival, such as mother's age and education, birth order, and gestational age, in order to gain insight into the causes underlying the persisting higher vulnerability of male sex in early life. The analysis was performed on babies dying during the perinatal period. These were subdivided into those who were stillborn and those who died during the first week of extrauterine life. A higher male excess among babies dying during the neonatal period than among those who were stillborn was always found in all classes of all factors. The finding of such generalized male overmortality in the early extrauterine period of life, together with the patterns shown by the temporal sex ratio in stillbirths and in early deaths, supports the hypothesis of a postponement of male risk from late fetal into neonatal life.

Postnatal development of the intrinsic nervous system in the circumvallate papilla-vonEbner gland complex.

We have studied the postnatal development of the intrinsic nervous system in the circumvallate papilla-vonEbner gland complex using NADPH-diaphorase cytochemistry, immunocytochemistry (for nitric oxide synthase-1 and alpha-internexin) and electron microscopy. In rats sacrificed in their first day post partum (1 p.p.), only isolated NADPH-diaphorase positive neurons were visible in the organ. At 2 p.p., a small group of neurons was visible at the base of the papillae and positive neurons formed short chains close to the developing glandular tubules. In the following days, the NADPH-diapharase positive cells increased in number and nerve fibres were associated to small ganglia located at the base of the papilla or in the gland. After the first week of extrauterine life, the intrinsic nervous system was similar to the intrinsic system of adult animals. An immunocytochemical positivity for nitric oxide synthase-1 appeared at 4 p.p. in neurons located in the gland and at 7 p.p. in cells located at the base of the papilla. Immunocytochemical staining for alpha-internexin showed that at 1 p.p. developing nerve fibres were present in the connective tissue of the tongue's muscle layer. At 2-3 p.p., developing nerve fibres were also present at the bases and in the core of the papilla. In the following days, the positivity for alpha-internexin was reduced and one week after birth was virtually absent. Ultrastructural examination revealed that since 1 p.p. isolated neurons can be found at the base of the papilla. In conclusion, the intrinsic nervous system originates from neurons present in the organ at the birth which, in the first days, undergo a biochemical and morphological maturation while the nerve fibres rapidly grow. These findings support the hypothesis that the intrinsic nervous system of the circumvallate papilla has a role in the maturation of the vonEbner gland.

Intra-epithelial lipids in the dorsoposterior area of the tongue in new-born rats

The mucosa covering the posterior surface of the tongue in new-born rats was studied by scanning and transmission electron microscopy. The results demonstrated that in the first days of extra-uterine life in the epithelium of this mucosa there is an accumulation of lipidic material, which appeared as round or oval droplets with a mean diameter of about 0.8–1.0 μm. Their density was homogeneously low and they did not contain fibrillar or granular material. In the first day of extra-uterine life, the droplets were scarce and mainly localized in the dorsal surface of the vallate papilla. In the following days, the lipid deposit was present in large areas of the posterior surface of the tongue. At the end of the first week of extra-uterine life, as well as in adult animals, the lipids were rather scarce. A multilocular lipid deposit was also visible in superficial cells detaching from the mucosa. With magnetic resonance spectroscopy, lipids extracted from the posterior mucosa of the tongue appeared mainly saturated. Small amounts of unsaturated and polyunsaturated lipid were also detectable. These findings suggest that in the first week of extra-uterine life, specialized areas of the oral epithelium store lipid.

Solitary chemosensory cells in the developing chemoreceptorial epithelium of the vallate papilla.

The solitary chemosensory cells are considered typical of aquatic vertebrates and have never been described in the oral cavity of terrestrial vertebrates. We describe elements with ultrastructural characteristics of the solitary chemosensory cell in the gustatory epithelium of rats in the first week of extrauterine life. These elements appeared isolated, located among keratinocytes, and wrapped by glial-like elements. They showed a bipolar shape with a round cell body, a thin apical process, and a thicker basal one. Nerve fibers contacted the cell body and the processes. The cells showed small dense granules mainly located near nerve contacts. Small bundles of tonofilaments were visible in the perinuclear cytoplasm. Similar elements were not found in rats after the first week of extrauterine life. The present study demonstrates in a mammal that the development of taste buds is preceded by the presence of epithelial elements with ultrastructural characteristics of the solitary chemosensory cells described in lower vertebrates. This finding suggests that the oral chemoreception in the suckling rats may be mediated by three different pathways (i.e., gustatory system, common chemical sense, and solitary chemosensory cell system).

Early changes in plasma brain and atrial natriuretic peptides in premature infants: correlation with pulmonary arterial pressure.

To define the change in plasma natriuretic peptides in newborns, we prospectively studied 10 premature infants. They were followed sequentially during the first week of extrauterine life by two-dimensional and pulsed Doppler echocardiography, and studied for atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP). We estimated mean pulmonary arterial pressure (MPAP) and measured blood pressure on days 1, 2, 3, 5, 7, respectively. Plasma ANP levels were 81.7 +/- 11.4 pg/ml on day 1 and 67.9 +/- 6.0 pg/ml on day 7, respectively. Between day 2 and day 7, there was a fall in MPAP, i.e. from 37 +/- 4 mmHg to 22 +/- 2 mmHg (P < 0.01), which was associated with a significant decrease in plasma BNP (41.8 +/- 10.1 pg/ml on day 2 vs. 10.4 +/- 0.9 pg/ml on day 7, P < 0.01). There was a positive correlation between MPAP and plasma BNP level (r = 0.643, P < 0.0001), but there was no correlation between MPAP and plasma ANP level. These data suggest that the pattern of secretion of BNP is different from that of ANP and that BNP levels reflect the changes of pulmonary arterial pressure in the neonatal period in premature infants.

147 TRANSIENT FORAMEN OVALE INCOMPETENCE IN NORMAL NEWBORNS

In contrast with the generally accepted mechanism of functional closure of the foramen ovale at birth, echocardiography studies in sick newborns revealed the presence of transient interatrial left to right shunts (IALRS) in several patients without structural heart disease. The aim of this study was to assess incidence and natural history of IALRS in healthy newborns. 20 healthy term newborns underwent an echocardiography and Doppler study daily during the first week after birth. Left atrial and aortic root dimensions were measured, as well as duration and direction of ductal and interatrial shunting. In 11 of these infants a predominant IALRS was detected on the first day of extrauterine life. In one infant IALRS persisted for as long as 6 weeks. Median persistance of IALRS in the remaining 10 infants was 3 days. Ductal left to right shunts were present in 3 infants with and in 2 without IALRS. There was no significant difference between infants with or without IARLS in respect to ductal patency, birthweight or sex. There was a statistically significant relation between lower gestational age and presence and duration of IALRS. We conclude that transient IALRS is common in normal newborns during the first week of extrauterine life. We suggest that this transient foramen ovale incompetence results from a relatively short foramen ovale flap in combination with the relative large extracellular volume as is present in the first days of life.

Pharmacokinetics of antihypertensive drugs in the neonatal period.

A consistent body of evidence indicates that in the preterm and full-term newborn drug disposition is reduced when compared to that of infants, grown-up children, and adults. Newborns are rarely treated directly with antihypertensive agents; however they can be exposed to the action of various antihypertensive drugs in utero and during their first week of extrauterine life in the case of hypertensive mothers treated through pregnancy. In such cases, the persistence of the antihypertensive agent during the first days of life may have important consequences on neonatal haemodynamics and on the function and the maturation of vital organs such as lungs and kidneys. The available information on the placental transfer and neonatal pharmacokinetics of alpha-methyldopa, clonidine, acebutolol, atenolol, betaxolol, metoprolol, propanolol, oxprenolol, and latetalol, are reviewed. Each product has its own pharmacokinetic characteristics which should influence, depending on the clinical situation, the therapeutic choice. In the presence of comparable efficacy, preference should be given to compounds with high bioavailability, eliminated mainly via metabolic degradation, with no active metabolites. In all cases, treatment should be discontinued 8-12 h before delivery.

Characterization of a developmentally regulated perinatal myosin heavy-chain gene expressed in skeletal muscle.

A cDNA clone, labeled pFOD5, isolated from a fetal-rat skeletal-muscle cDNA library, has been characterized and found to contain sequences corresponding to a perinatal-specific skeletal myosin heavy-chain (MHC) mRNA. This MHC cDNA demonstrates a high degree of nucleotide- and amino acid-sequence conservation with other MHC genes, but its carboxyl-terminal peptide and 3'-untranslated region are highly divergent and specific for this gene. S1 nuclease mapping experiments have shown that the perinatal MHC gene represented by this cDNA clone is only transiently expressed during skeletal-muscle development. Perinatal MHC mRNA is first detected late in fetal life, reaches maximal levels of expression at the end of the first postnatal week, and is de-induced thereafter. Its levels are almost undetectable at 28 days of postnatal life. During fetal and early postnatal life, the expression of this perinatal gene in skeletal muscle overlaps with the expression of the embryonic MHC gene. After the first week of extrauterine life, this gene is coexpressed with two adult MHC genes. The transient expression of this perinatal MHC gene raises interesting questions about the physiological significance of the MHC transitions and offers an interesting model for the study of MHC gene regulation.

Plasma 17-OH-progesterone in fullterm and preterm infants at birth and during the early neonatal period.

The 17 alpha-hydroxyprogesterone (17-HP) levels of cord and peripheral blood plasma were determined in fullterm and in preterm neonates, in order to investigate the normal concentration range during the first week of extrauterine life. In both fullterm and preterm neonates, the 17-HP level of the peripheral blood is substantially lower than that of the cord blood. In fullterm neonates (aged 1-7 days) the mean 17-HP concentration of the peripheral blood is higher in boys than in girls; the difference is significant (p less than 0.05). In preterm neonates, however, the 17-HP level of the cord blood is higher for girls than for boys, the difference again being significant (p less than 0.05).

457 THE EFFECT OF POSTNATAL AGE ON THE METABOLISM OF INTRAVENOUS FAT EMULSION

To determine the effect of postnatal age on serum clearing of intravenous fat, 17 preterm, AGA infants with gestation age of 29 ± 0.4 SEM wks. and birthweight of 1.2 ± 0.07 SEM kg. and less than 3 wks. of age received 1 gm/kg of Intralipid over a 4 hour infusion. Plasma levels of triglyceride (TG), free fatty acids (FFA) and beta-hydroxibutyrate (BOB) were determined at 0, 4, and 8 hours after the infusion was started. Basal levels of TG, FFA, and BOB were similar in the 2 groups. Infants of less than 1 wk. old had higher peak TG levels at the end of the infusion (4 hr.), than infants 2-3 wks. old (p<0.01). 8 hours after the beginning of the infusion TG levels remained significantly higher in the younger group (p<0.05).The rise in TG levels seen in our older group was lower than that (reported in infants of less than 33 wks. of gestation and comparable with levels obtained from infants of more than 33 wks. of gestation studied within the first 48 hours from birth. This suggests an acceleration in the capacity to tolerate intravenous fats after the first week of extra-uterine life.

Normal neonatal behavior patterns: the first week of extrauterine life.

Normal neonatal behavior patterns: the first week of extrauterine life.

Evaluation of hepatic function in newborn infants by means of chemical study of cord blood.

MOST AUTHORS still underestimate the role of the liver and of the reticuloendothelial system in the genesis of the various pathologic conditions that appear during the first week of extrauterine life. The variations in the degree of maturity of the hepatic functions in the newborn infant as evidenced in the chemistry of the cord blood might furnish some explanation of various so-called physiologic or undisputedly pathologic manifestations in such an infant like those grouped together under the name of hemolytic disease of the newborn. The object of our study was to determine the degree of maturity of the liver of newborn infants by studying the chemistry of the cord blood by various methods. In an additional series of cases, we compared (1) the results of our tests made on the blood of the mothers with those made on the cord blood and (2) with those made on the blood of

"THE CARE AND FEEDING OF INFANTS"

To the Editor: —The prevention of the initial loss of weight during the first week of extra-uterine life by the administration of sugar solution has been mentioned by the writer of the valuable series of papers on the care and feeding of infants (The Journal, January 13, p. 109), and credited to Schick. Dr. Charles Herrman, in a later issue (January 27, p. 273), claims priority, showing that in 1915 he published a paper in which he reported that the initial loss of weight may be prevented by the administration of a 10 per cent. solution of lactose every three hours. With a view of saving valuable space from further priority claims, may I intrude with the following facts drawn from ethnology, a field far removed from pediatrics, yet offering at times sound suggestions to those engaged in the care of infants, to the same extent as the Peruvian Indians