Ira H Gewolb

Stool microflora in extremely low birthweight infants

AIM To serially characterise aerobic and anaerobic stool microflora in extremely low birthweight infants and to correlate colonisation patterns with clinical risk factors. METHODS Stool specimens from 29 infants of birthweight <1000 g were collected on days 10, 20, and 30 after birth. Quantitative aerobic and anaerobic cultures were performed. RESULTS By day 30, predominant species were Enterococcus faecalis, Escherichia coli, Staphylococcus epidermidis, Enterbacter cloacae, Klebsiella pneumoniae, and Staphylococcus haemolyticus. Lactobacillus andBifidobacteria spp were identified in only one infant. In breast milk fed (but not in formula fed) infants, the total number of bacterial species/stool specimen increased significantly with time (2.50 (SE 0.34) on day 10; 3.13 (0.38) on day 20; 4.27 (0.45) on day 30) as did quantitative bacterial counts; Gram negative species accounted for most of the increase. On day 30, significant inverse correlations were found between days of previous antibiotic treatment and number of bacterial species (r=0.491) and total organisms/g of stool (r=0.482). Gestational age, birthweight, maternal antibiotic or steroid treatment, prolonged rupture of the membranes, and mode of delivery did not seem to affect colonisation patterns. CONCLUSIONS The gut of extremely low birthweight infants is colonised by a paucity of bacterial species. Breast milking and reduction of antibiotic exposure are critical to increasing fecal microbial diversity.

Glucocorticoid-Thyroid Hormone Interactions in Fetal Rat Lung

Summary: Previous studies have shown that triiodothyronine (T3) enhances the effect of dexamethasone on phosphatidylcholine (PC) synthesis in organ cultures of fetal rat lung. The aim of this study was to investigate whether similar interactions occurred in vivo and to explore possible mechanisms for this phenomenon.Injection of 7.0 mg/kg T3 into pregnant rats on d 18 and 19 of gestation resulted in a mean fetal serum T3 level of 2380 ng/dl on d 20 (control, 84 ng/dl) and in maximal (34%) stimulation of choline incorporation into PC. Injection of 1.0 mg/kg betamethasone using the same protocol as for T3 resulted in maximal stimulation of 33% and administration of both hormones together produced a 69% increase, an additive affect. The percentage of PC that was disaturated was increased with betamethasone, but decreased with T3. Betamethasone treatment resulted in an increase in the whole lung disaturated PC content, but treatment with T3 did not. Betamethasone administration also increased fetal serum T3 levels, but T3 injection did not produce elevated fetal serum corticosterone levels.Injection of T3 in vivo, or exposure of explants of 18-d fetal lung to 100 nm T3 for up to 48 h did not result in an increase in cytoplasmic glucocorticoid binding or nuclear translocation of the receptor steroid complex. Exposure of explants to glucocorticoid or T3 in vivo or in culture (dexamethasone, 100 nM and T3, 100 nM; for 48 h) resulted in a significant increase in the activity of cholinephosphate cytidylyltransferase, an enzyme in the choline incorporation pathway of PC synthesis. Exposure of explants to the combination of hormones resulted in stimulation that was equal to the sum of that produced by the single hormones but was not statistically significantly different from the glucocorticoid effect. The activities of other enzymes of phospholipid synthesis were not increased by exposure to either hormone, in vivo or in vitro.The additive effects of T3 and glucocorticoid with regard to choline incorporation into PC in fetal rat lung suggest that combined hormone therapy may be useful for the prevention of respiratory distress syndrome in humans. Further animal studies are required, however, before clinical use can be considered.

The relationship between rhythmic swallowing and breathing during suckle feeding in term neonates.

ABSTRACTS: Little is known of the development of efficient coordination between suckle feeding and breathing in human infants. To establish baseline data, we recorded breathing and swallowing activity during bottle feeds in 23 infants at 14–48 h postnatal age. Most swallows (overall mean 68%) were organized into runs, with intervals starting at 0.6–0.8 s and slowing to 1–1.3 s after 30–40 s. The proportion of run swallows to total swallows increased significantly with age. Swallow intervals were regular (coefficient of variation = 18–38%) compared with breathing (coefficient of variation = 50%). Both breathing rate and tidal volume were significantly reduced by the onset of suckle feeding, and the pattern of respiratory airflow became markedly irregular. Mild transient desaturation was common, but was not accompanied by changes in heart rate. Swallows could occur in all phases of breathing. Overall, equal numbers of swallows were preceded by expiration and inspiration, but twice as many were followed by expiration compared with inspiration. Swallows were classified by the respiratory phases both preceding and following the swallow. Swallows occurred in all possible classifications in each of the infants studied. The incidence of the most frequent classification (inspiration-swallow-expiration), was 24% overall (individual range 5–50%). The phase relation between swallows and breaths changed frequently but showed occasional short periods of stability during which the breathing became regular and tidal volume increased. We conclude that at <48 h the normal infants has little coordination between swallowing and breathing rhythms and maintains rhythmic swallowing at the expense of eupnea.

A randomized synbiotic trial to prevent sepsis among infants in rural India

Sepsis in early infancy results in one million annual deaths worldwide, most of them in developing countries. No efficient means of prevention is currently available. Here we report on a randomized, double-blind, placebo-controlled trial of an oral synbiotic preparation (Lactobacillus plantarum plus fructooligosaccharide) in rural Indian newborns. We enrolled 4,556 infants that were at least 2,000 g at birth, at least 35 weeks of gestation, and with no signs of sepsis or other morbidity, and monitored them for 60 days. We show a significant reduction in the primary outcome (combination of sepsis and death) in the treatment arm (risk ratio 0.60, 95% confidence interval 0.48–0.74), with few deaths (4 placebo, 6 synbiotic). Significant reductions were also observed for culture-positive and culture-negative sepsis and lower respiratory tract infections. These findings suggest that a large proportion of neonatal sepsis in developing countries could be effectively prevented using a synbiotic containing L. plantarum ATCC-202195.

Long-term colonization of a Lactobacillus plantarum synbiotic preparation in the neonatal gut.

Background: Probiotic, prebiotic, and synbiotic (a combination of pro- and prebiotic) supplements increasingly are being used to prevent and treat a variety of health conditions. Although colonization is considered a key element in the success of such treatments, few clinical studies have addressed colonizing ability. Studies are even more limited in neonates and infants, who may benefit most from such treatment. The present study was conducted to determine the colonizing ability, tolerance, and impact on the stool flora of 7 days of administration of a synbiotic supplement to a neonatal cohort, in preparation for a larger hospital-based trial. Patients and Methods: In this randomized, double-masked, controlled trial, healthy inborn newborns >35 weeks of gestational age and >1800 g birth weight were randomized between 1 and 3 days after birth to receive an oral synbiotic preparation (Lactobacillus plantarum and fructooligosaccharides) or a dextrose saline placebo. Two babies were treated with the synbiotic preparation for every 1 baby treated with the placebo. Duration of therapy was 7 days. Comprehensive stool cultures were done at baseline and on days 3, 7, 14, 21, and 28. Results: Nineteen infants received the active study supplement and 12 infants received the placebo for 7 days. L plantarum was cultured from the stools of 84% of the treated infants after 3 days of treatment, and from 95% of infants on day 28 after birth. Of the infants, 100%, 94%, 88%, 56%, and 32% remained colonized at months 2, 3, 4, 5, and 6, respectively. In both groups, the total mean number of species and the mean log colony counts increased over time. The number of bacterial species was significantly higher on days 21 and 28 in the synbiotic preparation group compared with placebo (P = 0.002 and 0.03, respectively). There was a linear increase in the mean log gram-negative colony counts in the placebo group during the 4-week period that was significantly higher than that in the Lactobacillus group on days 14, 21, and 28 (P < 0.001 for each). In contrast, the supplement group had significantly higher gram-positive colony counts on days 14 (P = 0.002) and 28 (P = 0.04). Only 1 infant in the placebo group was colonized with L fermentum during the first 28 days of life. No difference was found in the percent increase in weight between baseline and day 7, but on day 28 and months 2, 3, and 6, the percent increase from baseline was higher in the probiotic-treated group (P ≤ 0.05). The supplement was tolerated well. Conclusions: The synbiotic preparation colonized quickly after 3 days of administration and the infants stayed colonized for several months after therapy was stopped. There was an increase in bacterial diversity and gram-positive organisms and a reduction of gram-negative bacterial load in the treatment group. Because a combination preparation was used, it is difficult to specifically attribute the colonization to either the probiotic or prebiotic component in this study. Larger efficacy trials are warranted to examine the mechanism of action and precise effects of these supplements.

Delay in Pulmonary Glycogen Degradation in Fetuses of Streptozotocin Diabetic Rats

Summary: The developmental profile of pulmonary glycogen was investigated in fetuses of rats made diabetic before conception with the injection of 40 mg/kg streptozotocin.Lungs of control litters showed increasing pulmonary glycogen concentration from day 16–20, followed by significant decline by term (= 22 days). In contrast, the diabetic litters, which had pulmonary glycogen concentration equal to controls until day 20, showed significantly higher glycogen values (P < 0.01) on days 21 and 22, consistent with a delay in glycogen degradation. This coincided with the finding of decreased amounts of fetal pulmonary phosphatidylcholine and disaturated phosphatidylcholine on day 21 of the diabetic gestation (P < 0.05), but not before that time.Pulmonary glycogen phosphorylase A activity was significantly decreased in the diabetic litters on the final days of gestation, at the same time that the delay in glycogen breakdown became evident. Pulmonary glycogen synthase activity did not differ in the control and diabetic fetuses.Speculation: The delay in pulmonary glycogen degradation seen in the fetus of the diabetic gestation is thus temporally related to the delay in lung maturation seen in this model and may be secondary to a decrease in the activity of the glycogenolytic enzyme phosphorylase A. Decreased availability of pulmonary glycogen stores for surfactant synthesis may be important in elucidating the mechanism of the delayed pulmonic maturation seen in fetuses of diabetic pregnancies.

Respiratory patterns and strategies during feeding in preterm infants

Because patterns of integration of respiration into rhythmic suck‐swallow efforts are highly variable, we examined the vagaries of respiratory efforts as they evolve from the first tentative attempts at integration through more complex rhythmic interactions, with a focus on several strategies in which breathing and suck‐swallow are coordinated. Thirty‐four preterm infants (18 males, 16 females) of 26 to 33 weeks gestational age, 32 to 40 weeks postmenstrual age (PMA), and 2 to 12 weeks postnatal age were studied weekly from initiation of bottle feeding (using breast milk or preterm formula, both fed from a bottle) until discharge, with simultaneous digital recordings of pharyngeal pressure, nasal thermistor airflow, and thoraco‐abdominal strain‐gauge readings. Exceptional patterns of feeding‐adapted variations of respiration were noted, including breathing during swallow, alternating blocks of suck‐swallow and respiration efforts, narial airflow without thoracic movement, modulation of respiratory phase relationship against swallow rhythm, and paired rhythms with swallow:breath ratios of more than 1:1. Some of these strategies were developmentally regulated. Alternating blocks of suck‐swallow and respiratory efforts were only seen in the earliest (PMA 32–33 wks) studies. In contrast, coordination and phase relationships of suck‐swallow and breathing stabilized over time, as did the percentage of synchronized narial and thoracic respiratory efforts, which increased significantly after 36 weeks PMA compared with synchronization at 32 to 33.9 and 34 to 35.9 weeks PMA (p<0.05). There was also a significant positive correlation between percentage synchronization and PMA (r=0.58; p<0.001). The strategies and patterns noted here further clarify the developmentally regulated coordination of suck, swallow, and respiration into mature infant feeding, and may be predictive of those infants with short‐ and long‐term feeding or developmental difficulties.

Effect of Routine Vaccination on Aluminum and Essential Element Levels in Preterm Infants

ber that determines testis size and sperm production in adults. Sertoli cells develop during fetal and neonatal life and also at puberty when their number is definitively set. Our study suggests that breastfeeding is important for neonatal testes development because the inhibin B increase associated with breastfeeding was of the same magnitude as the proportion of Sertoli cells formed during the first year of life.5

Retinopathy of prematurity in infants weighing less than 500 grams at birth enrolled in the early treatment for retinopathy of prematurity study

PURPOSE To describe patient characteristics, classification, and onset of prethreshold retinopathy of prematurity (ROP), and ocular findings at 6 months corrected age in infants with birth weights <500 g who were enrolled in the Early Treatment for Retinopathy of Prematurity (ETROP) Study. DESIGN Multicenter randomized clinical trial. PARTICIPANTS Sixty-three infants with birth weights <500 g who developed ROP and were enrolled in the ETROP Study. METHODS Infants <1251 g at birth were logged at 26 study centers from October 1, 2000, to September 30, 2002, and underwent examinations for ROP. Infants who developed ROP and whose parents/legal guardians consented were enrolled in the ETROP Study. Infants who developed high-risk prethreshold ROP were randomized; 1 eye was treated early with peripheral retinal ablation and the other eye was managed conventionally, or, in asymmetric cases, the high-risk eye was randomized to early peripheral retinal ablation or conventional management. All eyes reaching prethreshold ROP were examined when infants reached 6 months corrected age. MAIN OUTCOME MEASURES Retinopathy of prematurity incidence, characteristics, and ocular findings among participants. RESULTS Thirty-four infants reached prethreshold or worse severity in 1 or both eyes. Retinopathy of prematurity was located in zone I in 43.3% of all prethreshold eyes, and plus disease was present in 46.7%. Median postmenstrual age for diagnosis of all prethreshold ROP was 36.1 weeks, but earlier (35.1 weeks) for eyes that developed high-risk prethreshold ROP. In the 27 surviving infants with prethreshold ROP, ophthalmic examination at 6 months corrected age showed a normal posterior pole in 22 (81.5%), a favorable structural outcome with posterior pole abnormalities in 4 (14.8%), and an unfavorable structural outcome (stage 4B) in 1 (3.7%). One infant developed amblyopia, 4 infants developed nystagmus, 4 infants developed strabismus, and 8 infants developed myopia >-5.00 diopters. CONCLUSIONS This is the first report on characteristics of prethreshold ROP in infants with birth weights <500 g. These infants are at high risk for developing prethreshold ROP, although many initially achieve a favorable structural outcome. They are at risk of developing strabismus, nystagmus, high myopia, and abnormal retinal structure and should therefore receive continued long-term follow-up. FINANCIAL DISCLOSURE(S) The author(s) have no proprietary or commercial interest in any materials discussed in this article.

A new look at the pathogenesis of the meconium aspiration syndrome: A role for fetal pancreatic proteolytic enzymes in epithelial cell detachment

We hypothesized that fetal pancreatic digestive enzymes play a role in the lung damage after meconium aspiration. We studied the effect of meconium on the A549 alveolar epithelial cell line. The exposure of the cells to 0.5 to 5% meconium resulted in significant disruption of connections between A549 cells and caused dose-dependent cell detachment, without signs of cell death. A protease inhibitor cocktail prevented the A549 cell detachment induced by meconium. After the exposure to 2.5% meconium, a protective effect was quantified by measuring light absorbance by gentian violet stain of still attached cells. The protease inhibitor cocktail and chymostatin showed significant protective effects, increasing the number of attached cells by 135 and 123%, respectively (p < 0.05). Other individual protease inhibitors tested in the detachment assay (AEBSF, leupeptin, E-64, aprotinin, benzamidine, phosphamidon, and aminohexanoic acid) did not offer statistically significant protection. These results afford a new perspective on the pathophysiology of meconium aspiration syndrome (MAS). We speculate that disruption of intercellular connections and cell detachment from the basement membrane are key events in the pathology associated with MAS. The observed protective effects of protease inhibitors suggest that they may be useful in the treatment and/or prophylaxis of MAS.