Spontaneous DNA synthesis of blood lymphoid cells in premature newborn infants,in older premature infants and in full-term newborn infants

In adults, blood cells which synthesize DNA spontaneously are large, pale lymphoid phagocytes. In fetal blood, transitional cells label spontaneously in addition to the lymphoid phagocytes (Prindull et al., 1975a, b). In the present study, we have measured quantitatively by scintillation counting, spontaneous thymidine incorporation of blood cells from different groups of infants.When compared with the conditions in the normal adult, spontaneous DNA synthesis of peripheral blood lymphoid cells is increased by a factor of 16.4 in premature newborn infants (P<0.002), by a factor of 8.7 in full-term newborn infants (P<0.01), and in older premature infants studied at the time of their calculated birth dates by a factor of 4.3 (P<0.001).Spontaneously labelling blood cells most likely are, at least in part, hematopoietic stem cells from the bone marrow.With technical assistance of Brigitte Prindull.     

Anogenital ratio: measure of fetal virilization in premature and full-term newborn infants

To provide normative data, we measured anogenital distances in 115 infants of 25 to 42 weeks gestational age and 10 pregnant women, including anus to fourchette (AF), anus to base of the clitoris (AC), and fourchette to base of the clitoris (FC). All infant measurements showed positive and significant correlations with body surface area, weight, length, and gestational age (P less than 0.001). However, the anogenital ratio (AF/AC) followed a normal distribution and did not correlate with any of the anthropometric variables or age. Mean (+/- SD) value in infants was 0.37 +/- 0.07, and in adults, 0.36 +/- 0.07. An anogenital ratio greater than 0.50 falls outside the 95% confidence limits, suggests labioscrotal fusion, and indicates a need for further evaluation. Because it is independent of body size and gestational age, the anogenital ratio should be useful in diagnosing androgen-induced labioscrotal fusion in both premature and full-term female infants.     

Selenium in the full-term and premature newborn infant

The following observations can be made on the basis of findings relating to selenium in serum samples taken from 55 neonates (35 born at term and 20 born pre-term): 1) the blood concentration of selenium in neonates born at term showed no substantial difference to that reported by other authors; moreover, there were no sex or birthweight-dependent variations, and no correlations were found with either the mother's age or the mode of engendering procreation; 2) the blood concentration of selenium in neonates born pre-term was 30% lower than that found in neonates born at term; it was correlated with gestational age and birthweight, but not with sex, mother's age or the mode of engendering procreation. It will be worthwhile continuing these tests in order to identify possible therapeutic uses of selenium in cases of deficiency.     

Vitamin A status in full-term and premature infants

Vitamin A status has been assessed by studying plasma vitamin A and retinol binding protein (RBP) levels in premature infants receiving 7,500 IU vitamin A/d (RDA 660-3,300 IU/d) and in control term babies during the 3 first months of life. Sampling was performed within the first week (D0-D7), between the 8th and the 30th day (D8-D30) and during the 2nd and the 3rd month of life (M2-M3). At D0-D7, vitamin A levels of the PTI group (28-32 weeks gestational age), PTII (33-36 weeks GA) and AT (control term newborn) were 242.1 +/- 20.5 (X +/- SEM), 176.1 +/- 12.3 and 213.1 +/- 17.1 micrograms/l respectively (P = 0.005). At D8-D30, these values were 264.2 +/- 26.0, 270.4 +/- 21.6 and 242.6 +/- 24.5 micrograms/l respectively (NS), and at M2-M3 234.2 +/- 21.6, 282.1 +/- 18.5 and 292.1 +/- 31.5 micrograms/l (NS). A significant difference was found between the values of the different dosage periods for PTII and AT groups; no difference in RBP levels was found either between groups or between dosage periods. At birth, our results show that the RBP synthesis is not closely linked to gestational age. The plasma vitamin A levels which rely on foetal stores and therefore on transplacental passage and on peripheral tissue requirements are low at 33-36 weeks gestational age. With a 7,500 IU daily supplement, excessively high vitamin A levels were not observed in premature infants; vitamin A and RBP levels in premature infants receiving supplement are not different from controls despite the 8-12-week term high vitamin A supply.     

Functional enteroinsular axis in full-term newborn infants

The term "enteroinsular axis" refers to the enhancement of insulin release by hormones secreted from the gut. Gastric inhibitory polypeptide (GIP) is one of the major hormones that mediates this function. The purpose of the present study was to examine whether the enteroinsular axis is functional in newborn infants born at term gestation. Between d 2 and d 4 of life, glucose was infused for 2 h intravenously or orogastrically to 44 fullterm newborn infants, of whom 18 were appropriate for gestational age, nine large for gestational age, eight small for gestational age; nine infants were born to diabetic mothers. Glucose was infused at either 8 mg/kg/min intravenously or 16 mg/kg/min orogastrically to achieve similar plasma glucose concentrations. Plasma insulin and GIP concentrations were compared. Plasma GIP concentration increased significantly with enteral glucose administration in all infants but remained unchanged with parenteral glucose infusion. The responses of plasma insulin and the insulin/glucose ratio were significantly greater in infants receiving enterally than parenterally infused glucose. However, when glucose was infused orogastrically at a lower rate (8 mg/kg/min), plasma GIP concentrations rose, but no enhancement of insulin response was detected, suggesting the importance of the role of circulating glucose in the "enteroinsular axis". The infants of diabetic mothers and the large-for-gestational-age infants had more rapid insulin response to orogastrically administered glucose, but their GIP responses were similar to that of normal infants. These findings suggest that, at term gestation, the newborn infants have a "functional" enteroinsular axis in response to glucose, i.e. the rising plasma GIP contributed in part to the enhanced insulin response to enterally infused glucose.(ABSTRACT TRUNCATED AT 250 WORDS)