ABSTRACT
OBJECTIVE: We aimed to determine whether vitamin D exposure, as estimated by use of multivitamins, is positively or negatively associated with recurrent wheezing in infants born preterm. STUDY DESIGN: This prospective cohort study enrolled 300 infants, born at 28(0/7) to 34(6/7) weeks gestational age, and conducted follow-up at 3-, 6-, 9- and 12-month adjusted age. RESULT: Black (55.9%) and non-black (36.6%) infants experienced recurrent wheezing. Adjusted odds ratios (ORs) for the association between multivitamin exposure at 3 months and recurrent wheezing were 2.15 (95% confidence interval (CI): 0.97, 4.75) for black and 0.43 (95% CI: 0.19, 0.96) for non-black infants with an interaction by race (P=0.003). In lag-effect models, ORs were 2.69 (95% CI: 1.41, 5.14) for black and 0.50 (95% CI: 0.27, 0.92) for non-black infants. CONCLUSION: Differences by race were seen in association between multivitamins and wheezing; population heterogeneity should be considered when evaluating vitamin supplementation.
Subject(s)
Dietary Supplements/adverse effects , Respiratory Sounds/drug effects , Vitamin D/adverse effects , Black or African American , Asian , Female , Follow-Up Studies , Gestational Age , Humans , Infant, Newborn , Infant, Premature , Male , Odds Ratio , Prospective Studies , White PeopleABSTRACT
OBJECTIVES: The objectives of this study were to (i) compare the strength of associations between sleep duration and body mass index (BMI) in middle childhood, and early and late adolescence; (ii) determine whether sleep duration in middle childhood predicts BMI in early or late adolescence; and (iii) examine the consistency of these associations by sex. METHODS: Subjects included 313 children/adolescents aged 8-19 participating in a longitudinal cohort study on sleep and health. Participants were assessed at three time points approximately 4 years apart: ages 8-11, 12-15 and 16-19. BMI z-score (BMIz) was calculated using age and sex normative data from the Centers for Disease Control. Sleep duration was reported by the parent (ages 8-15) or the adolescent (ages 16-19). RESULTS: [corrected] Half of the participants were male and 79% were Caucasian. Sleep duration had a negative linear association with BMIz for boys but not girls, and the magnitude of this association decreased with age. Sleep duration at age 8-11 predicted BMIz in early and late adolescence for boys but not girls, and associations were largely attenuated after adjusting for BMIz at age 8-11. The strongest predictor of adolescent BMIz was BMIz at age 8-11 for both boys and girls. CONCLUSION: We conclude that the association between sleep duration and BMIz varies by sex and age, with stronger associations in boys and in middle childhood compared with adolescence.
Subject(s)
Body Mass Index , Sleep/physiology , Adolescent , Age Factors , Child , Cohort Studies , Female , Humans , Longitudinal Studies , Male , Overweight/epidemiology , Overweight/etiology , Sex Factors , Time Factors , Young AdultABSTRACT
Most laboratory strains of the yeast Saccharomyces cerevisiae contain many copies of an autonomously replicating plasmid called 2-micron circle DNA. This plasmid codes for a site-specific recombinase, the FLP protein which promotes recombination across two 599-base pair inverted repeats of the plasmid DNA. We have cloned the FLP gene under the control of a strong Escherichia coli promoter and have hyperproduced the protein in that organism. Cell-free extracts from this source promote highly efficient site-specific recombination in vitro and we have used this activity to purify the FLP protein substantially. The enzyme acts efficiently on circular and linear substrates and requires only monovalent or divalent cations for activity.
Subject(s)
DNA Nucleotidyltransferases/genetics , Escherichia coli/genetics , Genes, Fungal , Genes , Plasmids , Saccharomyces cerevisiae/genetics , Amino Acid Sequence , Base Sequence , DNA Nucleotidyltransferases/isolation & purification , DNA Restriction EnzymesABSTRACT
Light and electron microscopic observations and biochemical analysis of the lingual cartilages from the Atlantic hagfish, Myxine glutinosa, reveal two different types of cartilage, designated types 1 and 2, respectively. The anterior and medial lingual are type 1, while the posterior lingual cartilage is type 2. Chondrocytes in type 1 cartilage are similar to those found in other vertebrate cartilages. The presence within the Golgi elements of material that resembles a component of the extracellular matrix suggests the involvement of active chondrocytes in the synthesis of the matrix. The matrix of the type 1 cartilage contains fibrils arranged to form concentric lamellae in the territorial matrix and irregularly arranged, branched fibrils in the interterritorial matrix. Biochemical analysis of the type 1 cartilage reveals that it is composed primarily of a cyanogen bromide (CNBr)-insoluble protein of unique composition that we have termed " myxinin ." Myxinin appears to be similar, but not identical, to lamprin . Type 2 cartilage bears no resemblance to any other known vertebrate cartilage. The principal cells are hypertrophied and are characterized by masses of cytoplasmic filaments. The appearance of the organelles in smaller nest cells suggests that nest cells are active in the production of some of the matrix, which consists primarily of collagen. Microfibrils and a basal lamina-like material are also present. Biochemical analysis of the type 2 cartilage reveals that the CNBr-insoluble material is different from myxinin . Comparisons of lamprey and hagfish cartilages prompt the concept that these two agnathans probably followed long-independent evolutionary histories.