Thyrotropin measured by the immunoradiometric assay in low birth weight infants

In 37 infants, the blood levels of TSH were determined by the immunoradiometric assay (IRMA) and the relation between TSH and thyroid hormone was evaluated. The ranges of gestational age (weeks) and birth weight (g) of infants were 28-42 and 982-3,650, respectively. The birth weights of 19 infants were below 2,500 g. The free T4 levels in the low birth weight (LBW) infants were lower than those of the normal infants and significantly correlated to the birth weight (r = 0.64, P less than 0.01) and gestational age (r = 0.58, P less than 0.01). In addition, free T4 levels were significantly correlated to the levels of total T4 (r = 0.66, P less than 0.01). The concentrations of TSH measured by IRMA method were significantly correlated to those of free T4 (r = 0.51, P less than 0.01). From these data, we consider that the transient hypothyroxinemia observed frequently in LBW infants might be a physiological reaction regulated by hypothalamus and that thyroid hormone treatment should be avoided.     

Effect of birthplace on infants with low birth weight.

From December 1983 to June 1985, 162 infants of less than 32 weeks'' gestation or weighing less than 1,500 g, or both, were cared for at the regional neonatal intensive care unit in Leeds. Of the 162, 64 (40%) were born in the unit because their mothers had received antenatal care there, 58 (36%) were born in another hospital and subsequently transferred, and 40 (25%) were transferred in utero because of potential complications. The overall mortalities for each group were 14%, 38%, and 18% respectively. These differences were significant, but when they were corrected for gestation, birth weight, and mode of delivery there was no difference in either the mortality or the incidence of intraventricular haemorrhage in the three study populations. Although there seem to be no distinct advantages of in utero transfer in terms of mortality and morbidity, there are other psychological and emotional advantages.     

Lowest neonatal serum sodium predicts sodium intake in low birth weight children

Forty-one children aged 10.5 +/- 0.2 years (range, 8.0-15.0 yr), born with low birth weight of 1,218.2 +/- 36.6 g (range, 765-1,580 g) were selected from hospital archives on the basis of whether they had received neonatal diuretic treatment or as healthy matched controls. The children were tested for salt appetite and sweet preference, including rating of preferred concentration of salt in tomato soup (and sugar in tea), ratings of oral spray (NaCl and sucrose solutions), intake of salt or sweet snack items, and a food-seasoning, liking, and dietary questionnaire. Results showed that sodium appetite was not related to neonatal diuretic treatment, birth weight, or gestational age. However, there was a robust inverse correlation (r = -0.445, P < 0.005) between reported dietary sodium intake and the neonatal lowest serum sodium level (NLS) recorded for each child as an index of sodium loss. The relationship of NLS and dietary sodium intake was found in both boys and girls and in both Arab and Jewish children, despite marked ethnic differences in dietary sources of sodium. Hence, low NLS predicts increased intake of dietary sodium in low birth weight children some 8-15 yr later. Taken together with other recent evidence, it is now clear that perinatal sodium loss, from a variety of causes, is a consistent and significant contributor to long-term sodium intake.     

Correlation of PP and PR intervals in premature low birth weight infants.

We examined the developmental change by which autonomic neural activity associated respiration modulates spontaneous firing rate of sinus (SA) node and atrioventricular (AV) conduction in premature infants born with low birth weight (LBWI). The purpose of this study was to clarify whether variation of PR is correlated with that of PP or those are independent in LBWI with immature autonomic nervous system. We investigated, therefore, whether there are spontaneous functional differences in the innervation of SA and AV nodes. Further, we evaluated the maturation of autonomic nervous system progressing in the period, on the day of birth (Day 0) to approximately one month after the birth (Month 1). This study was performed in thirteen LBWI during deep sleep. EEG, EOG, ECG, respiratory waves were digitized on line, spontaneous firing cycle of SA node (PP), and AV nodal conduction time (PR) that were recorded on Day 0 and Month 1. Then, the data were analyzed as follows: 1) correlations among the means and standard deviations (SD) of PP, PR and RR, 2) variance evaluation of PP and PR intervals by Lorenz plot analysis method, 3) correlation analysis among PP, PR and RR intervals by linear regression method and 4) frequency analysis for PP and PR intervals by high-speed Fourier transform method (FFT) and determination of frequency density. The PP interval decreased as growing in the period. Contrary PR interval increased. In LBWI, the automatic nervous activities including parasympathetic nerve activity for spontaneous firing cycle of SA node and ventricular excitation cycle on Month 1 were higher than Day 0. It was assumed that the vagal nerve activity for the AV conduction was enhanced. However, there was no significant change in linear regression slope for the spontaneous firing cycle of SA node and the AV conduction time. Postnatal LF/HF changes for PP and PR obtained by frequency analysis, were opposite. Therefore, it was suggested that the maturity of autonomic nervous system progresses in the period, Day 0 to approximately Month 1, but the variations in PP and PR are independent each other.     

T cell cytokines and the risk of blood stream infection in extremely low birth weight infants

Cytokines mediate the host immune response to infectious micro-organisms. The objective of this study was to determine whether immune regulatory interleukins (IL-4, IL-5, IL-6, and IL-10) and inflammatory cytokines (Interferon-γ [INF-γ], tumor necrosis factor-β [TNF-β], IL-2, and IL-17) are associated with an increased risk of developing blood stream bacterial/fungal infection (BSI) in extremely low birth weight (ELBW) infants. ELBW infants from 17 NICHD Neonatal Research Network centers without early onset sepsis were studied. Cytokines were measured from blood on days 1, 3, 7, 14, and 21 after birth. 996 ELBW infants contributed a minimum of 4080 unique measurements for each cytokine during the five sampling periods. Infants with BSI had lower levels of the inflammatory cytokines IL-17 (p=0.01), and higher levels of the regulatory cytokines, IL-6 (p=0.01) and IL-10 (p<0.001). Higher levels of regulatory cytokines relative to pro-inflammatory cytokines were associated with increased risk of BSI even after adjusting for confounding variables. In ELBW infants, the ratio of immune regulatory cytokines to inflammatory cytokines was associated with development of BSI. Altered maturation of regulatory and inflammatory cytokines may increase the risk of serious infection in this population.     

Early discharge of infants of low birth weight: a prospective study.

A total of 495 African infants of low birth weight were discharged from Harari Maternity Hospital, Salisbury, between October 1972 and September 1973. Criteria used for discharge were (a) no clinical evidence of disease, (b) satisfactory feeding by mouth (breast or bottle or both), and (c) stable temperature control under normal room conditions. Of the 495 babies 264 fulfilled these criteria when they weighed 1801-1900 g (group 1), 99 when they weighed 1901-2000 g (group 2), and 132 (group 3) when they weighed 2001-2500 g. The overall follow-up rate of those infants living in greater Salisbury was 85-5%, the health visitor playing an important contributory role in their progress, especially those in group 1. More than two clinic visits in the first four to five weeks after discharge were essential for continuing weight gain in groups 1 and 2 but not in group 3. The mean daily weight gain for all babies at the end of four to five weeks was 26 g. Readmission rates for babies in groups 1,2, and 3 were 9-5%, 1%, and 0-8%, respectively, the largest single cause for readmission being bronchopneumonia associated with hypothermia. Altogether 60% of the readmissions occurred during the two winter months (June and July). Hypothermia, associated with low environmental temperatures played a significant part in morbidity and mortality, and twins, particularly in group 1, had a mortality rate three times greater than singletons in the same group. In general, even in underdeveloped communities singleton babies born outside the winter months with reasonable clinic or home visiting facilities can be discharged at a weight of 1800 g or more.     

Effects of parenteral lipid infusion on DNA damage in very low birth weight infants

Very low birth weight (VLBW) infants are known to have poorly developed antioxidant system and may be at increased risk for radical damage. Previous studies have reported higher levels of lipid peroxide products in lipid emulsion used for parenteral nutrition. To examine the direct effects of parenteral lipid infusion on DNA damage in VLBW infants, we measured urinary 8-hydroxydeoxyguanosine (8-OHdG) levels in VLBW infants before, during, and after the parenteral lipid infusion. In both the lipid-infused and lipid-free groups, urinary 8-OHdG excretion levels at 14 days old were significantly (p < 0.01) lower than those at 2 and 7 days old. However, there were no significant differences in urinary 8-OHdG excretion levels between the lipid-infused and lipid-free groups at 2, 7, and 14 days old. Our results suggest that parenteral lipid infusion does not cause oxidative DNA damage, but irrespective of the infusion DNA damage during the first week of life is enhanced when compared with 14 days after birth in VLBW infants.     

Race and the inheritance of low birth weight

This paper uses intergenerational data from the Panel Study of Income Dynamics (PSID) to address the black-white difference in propensities toward low birth weight (LBW). We determine that socioeconomic conditions account for some variation in low birth weight across race. Further, while race differences in the risk of low birth weight cannot be explained entirely, we find that the inheritance of parental birth weight status dramatically reduces the black-white gap in low birth weight. Intergenerational legacies of poor infant health explain the largest share of racial disparities in filial birth weight. We then try to assess whether this intergenerational transmission of low birth weight is indeed genetic by using grandparent-fixed effects models to factor out, to a great extent, family socioeconomic circumstances. We find that even within this framework, both father's and mother's birth weight status have an important impact on filial outcomes. However, the degree of inheritance is weaker for African Americans than for other races. Finally, we theorize that the importance of paternal birth weight status implies a genetic association that does not work through the uterine environment but rather through the fetus itself.     

Incidence of low birth weight infants born to mothers with multiple risk factors

Low birth weight (LBW) is associated with a large number and variety of risk conditions during pregnancy. The number and types of risk conditions per pregnancy were determined in 1,864 white and 872 black mothers delivered at the University of Kansas Medical Center between 1975 and 1978. The incidence of LBW infants increased steadily among white and black mothers as the number of risk factors increased from none to three or four per pregnancy. Among pregnancies without spontaneous premature rupture of membranes (PROM), 51 percent of the LBW infants were born to mothers who had multiple risk factors associated with their pregnancies, even though only 18 percent of these pregnancies were associated with multiple risk factors. Among pregnancies with PROM, 72 percent were associated with multiple risk conditions, and 31 percent resulted in LBW infants. About 90 percent of LBW infants from PROM pregnancies had mothers with multiple risk factors. For all numbers of risk conditions, black mothers had a higher incidence of LBW infants than white mothers. Among black mothers without spontaneous premature rupture of membranes (PROM), the incidence of LBW infants increased from 3.2 percent (10/308) in low (zero)-risk condition pregnancies to 33 percent (16/49) among mothers with three or four risk conditions during the pregnancy. Among white mothers without PROM, the incidence of LBW infants increased from 1.7 percent (12/708) in low (zero)-risk condition pregnancies to 30 percent (19/64) in pregnancies with three or four risk conditions.(ABSTRACT TRUNCATED AT 250 WORDS)     

Oxidative stress in very low birth weight infants as measured by urinary 8-OHdG

Very low birth weight (VLBW) infants can be subjected to oxidative stress in the course of intensive care. We measured 8-hydroxydeoxyguanosine (8-OHdG), a biomarker of oxidative stress, and estimated the degree of oxidative stress in such infants. We also examined if the administered oxygen was related to oxidative stress. Urine samples of 50 Japanese VLBW infants [birth weights: 956.3+/-277.6g, and gestational ages: 28.0+/-2.6 weeks (mean +/- SD)] were collected on various postnatal days and 8-OHdG levels were determined using an ELISA kit. Sixteen term infants served as normal controls. As body weights at sampling increased, the average levels of urinary 8-OHdG decreased. 8-Hydroxydeoxyguanosine levels were: infants under 1000g, 29.5+/-16.4 micromol/mol creatinine (n = 24); 1000-1500g, 23.8+/-14.9 (n = 12); over 1500g, 16.1+/-8.5 (n = 14); and control, 10.9+/-7.2 (n = 16). Significant differences were found between <1000g group and > or = 1500g group (p = 0.0030), <1000g group and control (p < 0.0001), and 1000-1500g group and control (p = 0.0108). Also as postconceptional age at sampling increased, the average levels of 8-OHdG decreased. 8-Hydroxydeoxyguanosine levels were: infants before 252 days (36 weeks) of postconception: 27.4+/-15.5 micromol/mol creatinine (n = 34); after 252 days, 18.2+/-12.5 (n = 16). Differences between <252 days group and control (p < 0.0001), and <252 days group and > or = 252 days groups (p = 0.0253) were statistically significant. Among the three groups based on ambient oxygen concentration (21%, 22-29%, and > or = 30%) there was no significant difference (p = 0.417). The more premature the infants were, the more intense was the oxidative stress, hence, it is the prematurity rather than the administered oxygen which causes oxidative stress in VLBW infants. Drury et al. ["Urinary 8-hydroxydeoxyguanosine in infants and children" Free Radic. Res. 28 (1998) 423-4281 measured urinary 8-OHdG of 28 infants (24-40 weeks gestation) and found no gestation or birthweight related differences. This discrepancy seemed to be because of difference in birth weights and sampling period of the subjects.     

Beyond bacteria: a study of the enteric microbial consortium in extremely low birth weight infants

Extremely low birth weight (ELBW) infants have high morbidity and mortality, frequently due to invasive infections from bacteria, fungi, and viruses. The microbial communities present in the gastrointestinal tracts of preterm infants may serve as a reservoir for invasive organisms and remain poorly characterized. We used deep pyrosequencing to examine the gut-associated microbiome of 11 ELBW infants in the first postnatal month, with a first time determination of the eukaryote microbiota such as fungi and nematodes, including bacteria and viruses that have not been previously described. Among the fungi observed, Candida sp. and Clavispora sp. dominated the sequences, but a range of environmental molds were also observed. Surprisingly, seventy-one percent of the infant fecal samples tested contained ribosomal sequences corresponding to the parasitic organism Trichinella. Ribosomal DNA sequences for the roundworm symbiont Xenorhabdus accompanied these sequences in the infant with the greatest proportion of Trichinella sequences. When examining ribosomal DNA sequences in aggregate, Enterobacteriales, Pseudomonas, Staphylococcus, and Enterococcus were the most abundant bacterial taxa in a low diversity bacterial community (mean Shannon-Weaver Index of 1.02 ± 0.69), with relatively little change within individual infants through time. To supplement the ribosomal sequence data, shotgun sequencing was performed on DNA from multiple displacement amplification (MDA) of total fecal genomic DNA from two infants. In addition to the organisms mentioned previously, the metagenome also revealed sequences for gram positive and gram negative bacteriophages, as well as human adenovirus C. Together, these data reveal surprising eukaryotic and viral microbial diversity in ELBW enteric microbiota dominated bytypes of bacteria known to cause invasive disease in these infants.     

Serum selenium levels of the very low birth weight premature newborn infants with bronchopulmonary dysplasia

BackgroundThe selenium (Se) is an essential trace element that has a critical role in synthesis and activity of a number of selenoproteins with protective properties against free radical damage. This study was conducted to detect the serum Se concentration in very low birth weight (VLBW) preterm infants and its association with bronchopulmonary dysplasia (BPD).Materials and methodsCord blood Se concentration was determined in 54 neonates with gestation age 30 week or less. Another sample was obtained from these infants at day 28 of birth and serum Se levels were measured by atomic absorption spectrophotometer. All neonates were followed for oxygen dependency at 28 day after birth and 36 week postmenstrual age.ResultsThe mean cord blood Se concentration in studied neonates was 64.78 ± 20.73 μg L^?1. Serum Se concentration was 60.33 ± 26.62 μg L^?1 at age 28-day. No significant correlation was observed for serum Se concentration at birth and at one month after birth (r = ?0.04, p = 0.72). BPD was diagnosed in 25 neonates (46%). The mean serum Se concentration at one month was 57.16 ± 29.68 μg L^?1 in patients with BPD (25 cases) and 63.27 ± 23.6 μg L^?1 in 29 patients without BPD (p = 0.40).ConclusionIn our study, serum Se concentration at 28 day of birth was lower than cord blood levels in preterm neonates, but we have not found significant difference among patients who had BPD or not with respect to serum Se concentrations at this age.     

Outcome of infants of very low birth weight: a geographically based study.

The outcome of 143 live-born infants of very low birth weight (defined as less than 1500 g) who were born in 1980-81 to women resident in Newfoundland and Labrador is described. Sixty-one infants (43%) died during the first year of life. Of the 82 surviving infants 79 were followed for 18 months to 3 years. Eight (10%) were found to have evidence of severe neurodevelopmental abnormality, and nine (11%) were found to have various minor problems, including seizures, developmental delay and behavioural disorders. There was an inverse association between birth weight and mortality. Neonatal pneumothorax, seizures and clinical evidence of intraventricular hemorrhage were more commonly seen among infants who died; these factors also seemed to be predictive of an adverse long-term outcome. Continuous monitoring of the rates of death and disability among infants of very low birth weight born within a defined region should provide the basis for rational planning and delivery of neonatal intensive care.     

Latent anaphylactic sensitisation of infants of low birth weight to cows' milk proteins.

Latent systemic anaphylactic sensitisation to cows'' milk was assessed in 61 preterm infants who were randomly assigned to receive either a special formula for preterm infants based on cows'' milk or banked breast milk or one or other of these as a supplement to maternal milk. A single sample of venous blood was taken near to the time of discharge from the neonatal intensive care unit, and the histamine release by blood basophils in response to in vitro challenge with cows'' milk and anti-IgE was measured. Compared with the blood from infants fed on human milk, that from infants fed on preterm formula showed a significant increase in histamine release to challenge with cows'' milk, the response being greater in blood from infants of lower birth weight and gestational age. A smaller but significant increase in blood histamine release with anti-IgE challenge was observed in the group fed on preterm formula. Infants of low birth weight fed on preterm formula based on cows'' milk may develop latent systemic sensitisation more rapidly than infants born at term. The clinical importance of this requires further investigation.