Minimal enteral feeding, fetal blood flow pulsatility, and postnatal intestinal permeability in preterm infants with intrauterine growth retardation

OBJECTIVE: To study the effect of minimal enteral feeding (MEF) on intestinal permeability and feeding tolerance in preterm infants with intrauterine growth retardation (gestational age < 37 weeks, birth weight for gestational age p < 10). Furthermore, to determine whether fetal blood flow pulsatility or intestinal permeability predict feeding tolerance in these infants. DESIGN: Randomised controlled trial. METHODS: Within 48 hours of birth, infants were randomised to MEF or no enteral feeding (NEF) for five days in addition to parenteral feeding. Intestinal permeability was measured by the sugar absorption test before (SAT1) and after (SAT2) the study. The sugar absorption test measured the urinary lactulose/mannitol (LM) ratio after oral ingestion of a solution (375 mosm) containing mannitol and lactulose. Charts of all infants were assessed for measures of feeding tolerance. Fetal blood flow pulsatility index (U/C ratio) was measured within the seven days before birth. RESULTS: Of the 56 infants enrolled, 42 completed the study: 20 received MEF and 22 NEF. The decrease in LM ratio (LM ratio 1 - LM ratio 2) was not significantly different between the two groups (0.25 v 0.11; p = 0.14). Feeding tolerance, growth, and incidence of necrotising enterocolitis were not significantly different between the two groups. Neither the U/C nor the LM ratio 1 predicted feeding tolerance. CONCLUSIONS: The results suggest that MEF of preterm infants with intrauterine growth retardation has no effect on the decrease in intestinal permeability after birth. Neither fetal blood flow pulsatility nor intestinal permeability predicts feeding tolerance.     

The effect of a bifidobacter supplemented bovine milk on intestinal permeability of preterm infants

BACKGROUND: Preterm infants have increased intestinal permeability which can render them susceptible to infections from enterobacteriae. OBJECTIVES: The primary objective was to investigate whether probiotic administration to preterm infants decreases intestinal permeability. Secondary outcomes studied were: somatic growth, tolerance, rates of sepsis and necrotizing enterocolitis. METHODS: In a prospective randomized case-control study 41 stable preterm infants of 27 to 36 weeks gestation and 34 matched comparison infants consecutively admitted to the neonatal unit were studied. The study group received a preterm formula supplemented with Bifidobacter lactis (2 x 10(7) cfu/g of dry milk) while the control group received the same formula but without supplementation. Intestinal permeability was measured within two days of birth and then seven and thirty days later using the sugar absorption test. Additionally anthropometric parameters were recorded throughout the study as well as acceptance and tolerance of the formula. RESULTS: All infants tolerated the study formula well. Median counts of stool bifidobacteria and lactulose/mannitol ratios at baseline were comparable. After 7 days of supplementation median bifidobacteria counts were significantly higher in the study group than in the control group (p=0.0356) and they remained higher to the end of the study (p at day 30=0.075). The L/M ratio in the study group was significantly lower at day 30 of the study as compared to the control group (p=0.003). Head growth was significantly higher in the study group (p=0.001). CONCLUSIONS: The administration of a bifidobacter supplemented infant formula decreases intestinal permeability of preterm infants and leads to increased head growth.     

Effect of hyperbilirubinemia on intestinal permeability in healthy term newborns

We investigated the effect of serum bilirubin (SB) on intestinal permeability (IP) of healthy, term, birth weight appropriate for gestational age neonates before phototherapy. IP was measured by the dual probe (lactulose/mannitol) sugar absorption test (SAT) performed on the third day of life in 12 healthy jaundiced newborns (total bilirubin 249 +/- 39.75 micromol/L) and compared to that of 12 non-jaundiced newborns (total bilirubin 83.79 + 37.62 micromol/L) matched for sex, gestational age, birth weight and Apgar score. Jaundiced newborns have a significantly higher La/Ma ratio than non-jaundiced (0.31 +/- 0.28 vs. 0.053 +/- 0.043; p < 0.0004). A significant correlation was found between serum bilirubin level and La/Ma ratio (r = 0.56 p < 0.006). CONCLUSION: Our study demonstrates a direct effect of UCB on gut epithelial barrier of at-term newborns in whom UCB appears to be responsible for an alteration of IP that theoretically may lead to a passage of macromolecules through the intestinal epithelium increasing the risk of sensitization.     

The effect of antenatal vitamin A and beta-carotene supplementation on gut integrity of infants of HIV-infected South African women

BACKGROUND: Vitamin A is important for protection against diarrhea, and supplements may benefit gut function of infants of HIV-infected mothers. METHODS: We studied 238 infants of HIV-infected South African women participating in a randomized, double-blind, placebo-controlled trial of vitamin A during pregnancy (1.5 mg retinyl palmitate and 30 mg beta-carotene daily) plus 60 mg retinyl palmitate at delivery. The placebo group received identical placebo capsules at the same times. When infants were 1, 6, and 14 weeks of age, lactulose/mannitol dual sugar intestinal permeability tests were performed. RESULTS: Maternal vitamin A supplementation did not significantly affect infant gut permeability in the group as a whole at any time. By multiple regression analysis, HIV infection of the infant by 14 weeks was significantly associated with increased gut permeability at both 6 and 14 weeks. After controlling for birth weight, gestational age, current weight, feeding mode and recent morbidity, there was a trend toward an interaction between vitamin A supplementation and HIV infection (P = 0.086) at 14 weeks. Vitamin A made no difference to gut permeability of uninfected infants (lactulose/mannitol ratio for vitamin A group: 0.11, 95% confidence interval [CI] 0.08, 0.15, n = 73 and for placebo group: 0.09, 95% CI 0.06, 0.12, n = 76), but largely prevented the increase in the ratio of HIV-infected infants (vitamin A group: 0.17, 95% CI 0.13, 0.23, n = 23; placebo group: 0.50, 95% CI 0.37, 0.68, n = 20). The effects on the lactulose/mannitol ratio were related to changes in lactulose, not mannitol, excretion. Vitamin A supplementation was associated with significantly lower lactulose excretion at 1 and 14 weeks, suggesting the major effect of vitamin A was on maintaining the integrity of gut tight junctions. CONCLUSIONS: Vitamin A supplementation of HIV-infected pregnant women may prevent the deterioration in gut integrity in the subgroup of their infants who themselves become infected. Improving vitamin A status of HIV-infected infants may decrease their gastrointestinal morbidity.     

Gastrointestinal permeability changes in the preterm neonate.

The lactulose/L-rhamnose urinary excretion ratio during continued infusion of milks containing both sugars was used as an index of the permeability of the neonatal bowel to large and small molecules. Healthy infants of gestational age 31-36 weeks proved to have a period of enhanced permeability to lactulose during the first week of life, the lactulose/L-rhamnose excretion ratio being significantly higher on day 2 than on days 9 or 16 when a mature pattern of permeability could be seen. In infants traumatised by asphyxia or sepsis this change was much less pronounced. Healthy preterm infants of gestational age 26-29 weeks showed a ''mature'' pattern of permeability at birth, followed by a temporary period of enhanced permeability after 3-4 weeks of life. It is proposed that enhanced permeability to larger molecules is a specific temporary condition of the neonatal bowel in man as in other mammals, but the immunological implications in man remain to be established.     

Plasma homocysteine concentrations of preterm infants.

Mild hyperhomocysteinemia in adults is associated with an increased risk of vascular disease. Although information is available about plasma homocysteine concentrations in childhood, data are entirely lacking for preterm infants despite their known abnormalities of sulfur amino acid metabolism. We measured plasma total homocysteine concentrations of 9 preterm infants (gestational age 23-31 weeks) within 48 h of birth and over the subsequent 14 days of life, and 4 term infants (gestational age 36-39 weeks) on a single occasion within 72 h of birth. As measured within 48 h of birth, average plasma homocysteine and cysteine concentrations of the preterm infants were 3.8 +/- 0.3 and 122 +/- 8 microM, both significantly less than those of the term infants (6.1 +/- 1.3 and 187 +/- 39) and of normal adults (8.2 +/- 0.5 and 232 +/- 6). Plasma homocysteine (but not cysteine) appeared to gradually increase during the first 2 weeks of life (p = 0.053). Our results indicate that hyperhomocysteinemia does not normally occur in preterm infants.     

Free-radical-induced lipid peroxidation during the early neonatal period

The effect of gestational age on postnatal free-radical-mediated lipid peroxidation was studied in 19 term (gestational age 37–42 weeks) and 21 healthy preterm (gestational age 31–36 weeks) infants by measurement of expired ethane and pentane during the first 7 days of life. Ethane (11.9 versus 5.7 pmol/kg/min; p = 0.0001) and pentane (11.4 versus 7.5 pmol/kg/min; p = 0.01) were significantly higher in preterm than in term infants. Correlations were found between gestational age and ethane ( r = 0.60, p = 0.0001) for days 1–7 and pentane ( r = 0.54, p = 0.0003) for days 3–7; and between birth weight and ethane ( r = 0.58, p = 0.0001) and pentane (r = 0.55, p = 0.0003). These results indicate that during the postnatal period, immaturity is a major factor determining the rate of free-radial-mediated lipid peroxidation.     

Nitric oxide levels in preterm and term infants and in premature infants with bacteremia

OBJECTIVE: To determine the serum nitric oxide levels in healthy neonates and in infants with bacteremia. METHODS: We performed a prospective study in a tertiary neonatal intensive care unit. The serum nitric oxide levels were measured in all infants at birth (basal) and in the infected neonates also on the first 2 days of bacteremia. RESULTS: Thirty-three neonates (10 term, 23 preterm) were included. Eleven preterm infants (mean gestational age 27 weeks) had bacteremia. The main blood culture isolates included coagulase-negative staphylococci (n=4), Klebsiella pneumoniae (n=3), and Escherichia coli (n=3). The serum nitric oxide levels increased during infection in 10 infants (p <0.008). The mean nitric oxide level before infection was 44 microM and during infection 96 microM (p=0.008). In the healthy babies, the mean nitric oxide level was 26 microM in those with a gestational age <27 weeks, 44 microM in those born between 28 and 36 weeks of gestation, and 63 microM in term infants. CONCLUSIONS: Bacteremic preterm infants produce significantly higher amounts of nitric oxide. The basal nitric oxide levels at birth may be correlated with gestational age.     

Epidemiology of altered intestinal permeability to lactulose and mannitol in Guatemalan infants

BACKGROUND: Subclinical alterations of small intestinal function have been reported frequently in tropical countries. Studies of small intestinal permeability to lactulose and mannitol were therefore completed in Guatemalan infants from a low-income, periurban community to assess the prevalence of altered intestinal function and the factors associated with this condition. METHODS: Two hundred studies were successfully completed in 158 infants who had been free of diarrhea for at least 1 week before the day of study. Urinary concentrations of lactulose and mannitol during the 5-hour period after ingestion of 400 mg/kg body weight of lactulose and 100 mg/kg body weight of mannitol were measured by gas-liquid chromatography and compared by age group, feeding practices, anthropometric indexes, and serum iron and zinc concentrations. RESULTS: The overall prevalence of altered intestinal permeability (defined as a ratio of urinary recovery of lactulose to mannitol [L/M] > or =0.07) was 30%. The urinary L/M recovery ratio was positively associated with age; low weight for age; and, in infants less than 6 months of age, non-breast-feeding. Children with serum iron concentrations less than 7.16 microM/l (40 [microg/dl) had higher median L/M ratios (L/M = 0.068; 95% confidence interval [CI], 0.054, 0.085) than those with iron levels higher than this cutoff (L/M = 0.052; CI = 0.046, 0.058; p = 0.038). The median urinary L/M recovery ratio in 10 currently asymptomatic infants who had diarrhea during the week before testing (0.087; CI = 0.49, 0.154) was higher than that in children who had been free from diarrhea for at least 1 week (0.052; CI = 0.048, 0.056; p = 0.01). CONCLUSION: Age, feeding practices, low weight-for-age, low serum iron concentration, and recent diarrhea were all associated with altered intestinal function in this group of Guatemalan infants.     

Low thymic size in preterm infants in the neonatal intensive care unit,a possible marker of infection? A prospective study from birth to 1 year of age

Aim: To study the growth of the thymus in preterm infants. Methods: Ultrasonographic thymic size (Ti) was studied in 80 preterm infants (gestational age 24–36 weeks) from birth to discharge from the neonatal intensive care unit (NICU). Thirty‐three of these infants were followed to 1 year of age. Results: At birth, the median Ti was 5.2 compared with 11.8 in term infants. At discharge, the median Ti was 10.0 and not significantly different from Ti in term infants at birth (p = 0.22). The size of the thymus was significantly associated with postmenstrual age and weight (both p < 0.01). Infections during admission were negatively associated with the size of the thymus (p < 0.01). During the first 3 months after discharge, preterm infants had a significantly higher frequency of infections than did term infants (p = 0.002); hereafter, the preterm infants had significantly fewer infections than term infants (p = 0.002). The median Ti in preterm infants and term infants at 1 year of age was 21.1 and 17.3, respectively. This difference was not statistically significant (p = 0.41). Conclusions: Growth of thymus was not compromised by preterm birth. Ti is negatively associated with the frequency of infections in preterm neonates submitted to NICU.     

Iron status in low-birth-weight infants, small and appropriate for gestational age. A follow-up study

Iron nutrition was measured in 84 low-birth-weight infants. At birth, they were assigned to three groups: preterm infants appropriate for gestational age (n = 29); preterm infants small for gestational age (n = 17); and full-term infants small for gestational age (n = 38). A sub-sample of infants was supplemented with iron 3 mg/kg from two to four months of age. At birth, preterm appropriate-for-gestational-age infants had a lower hemoglobin concentration than full-term small-for-gestational-age infants (p < 0.01) and a higher serum ferritin than preterm small-for-gestational-age infants (p < 0.05). In the non-supplemented group, full-term small-for-gestational-age infants had significantly higher hemoglobin concentrations at four months of age. At this age, iron-supplemented preterm infants appropriate or small for gestational age had significantly higher hemoglobin levels than non-supplemented subjects, while iron supplementation did not have an effect on final hemoglobin concentration in full-term small-for-gestational-age infants. We conclude that preterm infants, irrespective of their adequacy for gestational age, show evidence of iron deficiency before four months of age. Full-term infants do not develop iron deficiency up to this age.     

Measurement of transepidermal water loss in Tanzanian cot-nursed neonates and its relation to postnatal weight loss

In healthy cot-nursed Tanzanian neonates ( n = 92, gestation 26–42 weeks) measurements of transepidermal water loss (TEWL) and weight change were performed during the first 24 h after birth at an average ambient humidity of 70% and an environmental temperature of 32°C. Urine production on day 1 (ml/kg per 24h) was documented for a subgroup of 13 preterm and 8 term infants. In a limited group of preterm infants ( n = 5) TEWL measurements, weight and 24 h urine volume measurements were repeated daily for 7 days. Maximum weight loss was determined in 7 preterm (gestational age 30–36 weeks) and 6 term infants. TEWL was estimated by measuring the evaporation rate at three sites of the body using the water vapour pressure gradient method. On day 1, TEWL was highest in the most preterm infants, whereas TEWL and urine production were higher in large for gestational age infants as compared to appropriate for gestational age (AGA) infants of the same gestational age (31–36 weeks). For the whole group, weight loss on day 1 was correlated with TEWL ( r = 0.49, p <0.05). At follow-up TEWL in preterm infants remained almost constant during the first 4 days and decreased after the fourth day, at which time weight gain commenced. Preterm AGA infants (gestational age 24–37 weeks) showed a mean postnatal weight loss of 4.4% of the birth weight, while in term infants this loss was only 2.6%. A reduced postnatal weight loss as compared to Caucasian infants may be explained by a lower water loss during the first days after birth, through both skin evaporation and urine excretion.     

Birth weight categorization according to gestational age does not reflect percentage body fat in term and preterm newborns

This study was performed to prove the applicability of the small-for-gestational age (SGA), appropriate-for-gestational age (AGA), and large-for-gestational age (LGA) classification depending on birth weight to predict percentage body fat (%BF) measured by dual-energy X-ray absorptiometry (DXA) in term and preterm infants. The data of 159 healthy term and preterm neonates (87 boys and 72 girls) with a gestational age at delivery of 38.4 weeks from two longitudinal studies were analyzed. Anthropometry and body composition data were assessed within the first 10 days after birth. Correlations between anthropometric parameters and fat mass measured by DXA were calculated. Prevalences of observations with low, middle, and high %BF measured by DXA were compared between SGA, AGA, and LGA groups, according to sex and gestational age. In term infants, 42.9% of the newborns with less than 10% body fat were classified to be AGA; 9.9% of all AGA newborns had less than 10% body fat. For the whole group, among the ratios investigated, the weight-length ratio (r=0.82) showed the best correlation to fat mass measured by DXA. The %BF at the time of study was higher in girls (14.75%) than in boys (11.95%). In conclusion, traditional classification based on birth weight centiles does not reflect %BF in term and preterm newborns.     

A developmental study on types and frequency distribution of short apneas (3 to 15 seconds) in term and preterm infants

We measured the frequency distribution and the ventilatory correlates of the various types of apneas 3 to 15 s long during sleep in eight term infants (birth weight 3.65 +/- 0.16 kg; gestational age 39.5 +/- 0.3 wk) and eight preterm infants (birth weight 2.07 +/- 0.18 kg; gestational age 34.3 +/- 0.4 wk). Each infant was studied on five to seven occasions from birth to 56 wk of postconceptual age using a modified flow-through system. Sixty-six paired epochs of quiet sleep (1163 min) and rapid eye movement sleep (829 min) were analyzed in term infants and 85 paired epochs of quiet sleep (1553 min) and rapid eye movement sleep (1328 min) in preterm infants. Of the 783 apneas recorded in term infants 82% were central, 1.5% obstructive, 0.5% mixed, and 16% were of the breath-holding type; the corresponding figures for the 4086 apneas recorded in preterm infants were 93, 0.5, 1.0, and 5.5%. This distribution was similar in the two sleep states but term infants had a higher percentage of breath-holding apneas than preterm infants (p less than 0.01). In preterm infants the rate of central apneas decreased with postnatal age (p less than 0.01); in term infants the rate did not change significantly. The duration of apneas showed a modal distribution for central apneas at about 8 s for both groups during the 1st month of life (p less than 0.05). The findings suggest: 1) apneas in the newborn and early infancy are primarily central and are more frequent in preterm than in term infants.(ABSTRACT TRUNCATED AT 250 WORDS)     

Intestinal permeability in different feedings in infancy

AIM: To determine the intestinal permeability (IP) as a marker of intestinal epithelial integrity in formula-fed infants compared with healthy breast-fed infants. METHODS: IP was measured in 57 healthy infants less than 4 months old. A dual sugar test with lactulose and mannitol was performed. Three urinary ratios were established: lactulose/mannitol (L/M), lactulose/creatinine (L/C) and mannitol/creatinine (M/C). Five groups were studied: breast-fed (n = 11), prebiotic supplemented formula (n 17), nucleotides supplemented formula (n = 9), LC-PUFA supplemented formula (n = 9) and LC-PUFA and nucleotides supplemented formula (n = 11). RESULTS: We have not found any difference in IP between breast-fed and formula-fed infants nor when the different formulas are compared with each other. The indirect information of the paracellular pathway by the ratio L/C and the transcellular route by the ratio M/C reflects some difference when the ingredients added are fructooligosaccharides and galactooligosaccharides, expressing a higher degree of lactulose permeation with respect to mannitol. When LC-PUFA supplementation was evaluated a lesser ratio of L/C was found, expressing intestinal barrier related to a process of epithelial tight. CONCLUSIONS: The most important factor in the maintenance of the integrity of epithelial barrier function is probably the delivery of nutrients in the gastrointestinal tract. The role of the different ingredients added should be clarified.     

Lactulose-mannitol intestinal permeability test in children with diarrhea caused by rotavirus and cryptosporidium. Diarrhea Working Group, Peru

BACKGROUND: The relationship between intestinal permeability and acute secretory diarrheal syndromes caused by rotavirus and Cryptosporidium parvum in infants less than 36 months of age was studied using the lactulose-mannitol excretion assay. METHODS: An oral solution containing 0.4 g/kg lactulose and 0.1 g/kg mannitol was administered to 15 infants with rotavirus, 7 with Cryptosporidium infection and a control group of 7 with secretory diarrhea admitted to the Oral Rehydration Unit of the National Children's Hospital in Lima, Peru. Urinary sugar excretion was measured using an enzymatic spectrophotometric method. The ratio of urinary excretion of lactulose to mannitol was used to measure intestinal mucosal permeability, with higher ratios indicative of increased intestinal permeability. Infants in all three groups were retested 20 days after the initial test. RESULTS: The (mean +/- SE) lactulose:mannitol (L:M) excretion ratios during the acute phase (day 1) of diarrhea in infants with rotavirus or Cryptosporidium and control infants were 0.67 +/- 0.1, 0.76 +/- 0.16, and 0.26 +/- 0.04, respectively. In the convalescent phase (day 20) the ratios were 0.19 +/- 0.02, 0.28 +/- 0.05, and 0.29 +/- 0.07, respectively. Significant reductions in L:M ratios were noted in rotavirus patients between days 1 and 20 (paired t-test; P < 0.01), Cryptosporidium patients between days 1 and 20 (paired t-test; P < 0.05), and between control subjects on day 1 and rotavirus patients on day 1 and Cryptosporidium patients on day 1 (unpaired t-tests; P < 0.05 for both). There were no significant differences in control subjects between days 1 and 20, control subjects and rotavirus patients on day 20, or control subjects and Cryptosporidium patients on day 20. CONCLUSIONS: The results indicate that increased intestinal permeability caused by rotavirus or cryptosporidium infections in Peruvian infants less than 36 months of age is a significant but reversible phenomenon. The temporal relationship observed in the current study and the contribution of such alterations in intestinal mucosal integrity to the burden of diarrheal disease and the development of malnutrition in developing countries is discussed.     

Longitudinal development of specific and functional antibody in very low birth weight premature infants

We evaluated the formation of specific and functional antibody in preterm infants born weighing less than 1500 g (mean 1088 g) and less than 32 wk gestational age (mean 28.8 wk). Plasma IgG antibody against tetanus and diphtheria toxoids were measured by an enzyme-linked immunosorbent assay. Opsonic activity of heat-inactivated plasma was measured using radiolabeled bacteria, adult polymorphonuclear leukocytes and exogenous human complement. In the presence of complement, the strain of coagulase negative staphylococcus used was opsonized by IgG antibody, and the strain of Escherichia coli by IgM. Geometric mean plasma levels of tetanus and diphtheria IgG antibody fell from birth to 4 months chronological age, but rose significantly by 9 months (approximately 2 months after the third dose of diphtheria, tetanus, pertussis vaccine). However, at 9 months they remained lower than the respective geometric mean levels in 9-month-old term infants (tetanus: p less than 0.001; diphtheria: p = 0.02). The preterm infants' mean plasma IgG staphylococcal opsonic activity fell from birth to 2.5 months, but by 9 months was comparable to that of term infants of the same age. Mean IgM opsonic activity for E. coli was very low at birth in both preterm and term infants. It rose with chronological age, correlating with the rise in total IgM (r = 0.48, p less than 0.001) and by 9 months the mean preterm and term infants' levels of IgM opsonic activity for E. coli were comparable.(ABSTRACT TRUNCATED AT 250 WORDS)     

Increased beta-lactoglobulin absorption during rotavirus enteritis in infants: relationship to sugar permeability

We studied absorption of the potentially allergenic protein beta-lactoglobulin during acute rotavirus diarrhea in infants and assessed the relationship of this macromolecular absorption with intestinal sugar permeability. After oral rehydration, 38 patients with acute gastroenteritis were given orally a 100-ml solution containing 4 g (11.7 mmol/L) of lactulose and 0.8 g (4.4 mmol/L) of mannitol, and their recovery rate as shown in urine passed during the subsequent 5 h was measured. A blood sample was taken 2 h after a milk feed for ELISA measurement of beta-lactoglobulin in circulating immune complexes. Twelve nondiarrhea patients were studied after an overnight fast as controls. Immune complexes containing beta-lactoglobulin were found in the serum of all, but the levels [median (range)] were significantly higher in patients with rotavirus diarrhea [686 (36-4352)] than in nondiarrhea patients [165 (0-2594)]; p = 0.007. The mean (95% confidence interval) lactulose/mannitol urinary recovery ratios were increased in patients with acute diarrhea [0.19 (0.10, 0.30)] compared to nondiarrhea patients [0.01 (0.005, 0.02)]; p = 0.0001. Thus, a significant correlation between beta-lactoglobulin absorption and sugar permeability was found; Spearman's rank correlation coefficient = 0.42, p = 0.004. This correlation was not, however, direct but was due to an inverse relationship between urinary recovery of mannitol and serum beta-lactoglobulin immune complexes. These results indicate that rotavirus gastroenteritis is associated with enhanced beta-lactoglobulin absorption and elevated lactulose/mannitol permeability test results, but these represent different phenomena.     

Erythrocyte insulin binding in preterm newborn infants

To characterize the erythrocyte insulin receptor in newborn infants we studied the binding of 125I-insulin to the erythrocytes from 42 preterm infants (14 at birth, 14 aged 2-7 days, and 14 aged 8-16 days) with a mean gestational age of 34.1 wk, and from 32 term infants (16 at birth and 16 aged 2-7 days). The insulin binding to cord blood erythrocytes from preterm infants was significantly higher than that of cord blood cells from term infants and to postnatal cells from preterm as well as term infants. The erythrocytes from preterm infants aged 2-7 days bound more insulin than cells from preterm infants aged 8-16 days. The maximum insulin binding (specific insulin binding at tracer concentration of insulin) correlated negatively with the gestational age both at birth and over the 1st postnatal wk. In the preterm infants there was a strong negative correlation between the maximum insulin binding and postnatal age. The enhanced insulin binding to cord blood erythrocytes from preterm infants was due to both an increased receptor concentration and a high affinity for insulin. The increased affinity persisted over the 1st wk of life. In preterm infants older than 1 wk the insulin binding characteristics were basically similar to those in term newborn infants. In all infants studied the receptor concentration seemed to be postnatal age dependent while the receptor affinity was gestational age dependent. No correlation was found between the insulin binding data and the plasma concentrations of immunoreactive insulin or C-peptide.(ABSTRACT TRUNCATED AT 250 WORDS)     

Placental transfer and decay of varicella-zoster virus antibodies in preterm infants

OBJECTIVES: To compare the placental transfer of maternal varicella-zoster (VZV) antibodies to preterm and term infants and to investigate antibody decay during the first 6 months of life in the preterm infants.Study design: Maternal and umbilical cord blood samples were taken from 113 healthy mother-newborn pairs: 64 term (gestational age > or =37 weeks) and 49 preterm (gestational age < or =35 weeks). Premature infants were further tested at 1, 2, and 6 months. Anti-VZV antibody to membrane antigen was measured with the immunofluorescent technique. RESULTS: Preterm infants of gestational age < or =28 weeks had positive cord antibody and a geometric mean titer significantly lower than those in preterm infants of gestational age 29 to 35 weeks and term infants (25% vs 95% and 95%, respectively, P <.001 for each, and 2.5 +/- 2.2 vs 10.5 +/- 2.4 and 12.6 +/- 2.4, respectively, P <.001 for each). There was no difference between the preterm 29 to 35 weeks of gestation and term groups. Fetal-maternal ratios for both preterm groups were <1 and were significantly less than the fetal-maternal ratio in the term infants. The transfer of maternal antibodies to term infants was significantly greater than to the 29- to 35-week preterm infants (P =.01). At 2 months of age, 25% of 29- to 35-week preterm infants and no preterm infant < or =28 weeks had a positive titer. At 6 months of age, all preterm infants were seronegative, and the geometric mean titer in both groups declined to undetectable levels. CONCLUSION: Transplacental transfer of maternal VZV antibodies is diminished in preterm infants. VZV antibody levels are significantly lower in preterm infants born at < or =28 weeks' gestational age compared with those in preterm infants 29 to 35 weeks' gestational age and term infants. Anti-VZV titers decrease to undetectable levels in preterm infants by 6 months of age or earlier; thus these infants appear to be susceptible to chickenpox before the scheduled 12-month vaccination.