Infant feeding practices and reported food allergies at 6 years of age.

OBJECTIVE: The goal of this study was to identify the frequency of physician-diagnosed food allergies among 6-year-old US children and study the impact of exclusive breastfeeding and complementary food introduction on this frequency. METHODS: Data were analyzed from children who participated in the Infant Feeding Practices Study II Year 6 Follow-Up Study (Y6FU). Children with probable food allergy (pFA) were defined as children with report of physician-diagnosed food allergy at age 6 years. Subgroups of pFA included children who were not diagnosed before 1 year of age (new pFA) and those with atopic risk factors (high risk). RESULTS: Prevalence of total pFA in the Y6FU was 6.34%. The majority of these children had new pFA and high-risk factors. Higher maternal education, higher family income, family history of food allergy, and reported eczema before 1 year of age were significantly associated with higher odds of total or new pFA. Exclusive breastfeeding duration and timing of complementary food introduction were not significantly associated with total pFA. However, exclusive breastfeeding of ≥4 months compared with no breastfeeding was marginally associated with lower odds of new pFA (adjusted odds ratio: 0.51; P = .07); this effect was not observed with high-risk children. CONCLUSIONS: Analysis of infant and maternal variables in the Y6FU cohort of US children revealed that socioeconomic and atopic factors were the main predictors of pFA at age 6 years. Exclusive breastfeeding of ≥4 months may have a preventive effect on development of pFA after 1 year of age in non high-risk children.

A high-throughput method for monitoring changes in homeobox gene expression.

Members of the homeobox gene superfamily of transcription factors are essential determinants of cellular identity during development. Their regulation and downstream gene targets are not well understood, however. This is due, in part, to the large number of genes that need to be analyzed simultaneously. A method has been developed for the rapid and simultaneous detection of changes in the expression of homeobox-containing genes, including members of the developmentally important Hox gene family. The method selectively amplifies and labels homeobox-containing mRNAs using a 3'-RACE procedure in combination with a degenerate forward primer that targets a highly conserved region of the homeobox found in all vertebrate Hox genes and many non-Hox homeobox-containing genes. The amplified sequences are identified by hybridization to a membrane-based array of covalently bound Hox and non-Hox homeobox gene sequences of interest. The method has been used here to demonstrate previously undetected changes in the expression of homeobox genes during retinoic acid-induced nerve cell differentiation in mouse pluripotent P19 cells.

Maternal exposure to androstenedione does not induce developmental toxicity in the rat.

Thirty-day old female rats received corn oil or androstenedione (in corn oil) at one of four concentrations (5.0, 10.0, 30.0 or 60.0 mg/kg body weight) by gavage for two weeks prior to mating, during the mating period and until gestation day (GD) 19. Caesarean sections were performed on GD 20. No dose related changes were observed in serum androstenedione, estradiol, LH, FSH, testosterone or progesterone. A statistically significant decrease in estrous cycle length was observed in the 60.0 mg/kg dose group only. Feed and fluid consumption, mean body weight gain, organ weight and fetal parameters were not affected by androstenedione treatment. At the doses given, androstenedione had no specific effect on the development of individual bones or soft tissues.