Background Birth by cesarean section is associated with increased risks of immune disorders. We tested whether establishment of immune function at birth relates to mode of delivery, taking other maternal and infant characteristics into account. Methods and findings Using a prospectively collected database, we retrieved information on maternal and infant characteristics of 6,014 singleton infants delivered from February to April 2014 in Stockholm, Sweden, with gestational age ≥35 weeks, Apgar scores ≥7, and without congenital malformations or any neonatal morbidity. We linked our data to blood levels of T-cell receptor excision circles (TREC) and κ-deleting recombination excision circles (KREC), determined as part of a neonatal screening program for immune-deficiencies, and representing quantities of newly formed T- and B-lymphocytes. Multivariate logistic regression was used to calculate odds ratios (OR) with 95% confidence intervals (CI) for participants having TREC and KREC levels in the lowest quintile. Multivariate models were adjusted for postnatal age at blood sampling, and included perinatal (mode of delivery, infant sex, gestational age, and birth weight for gestational age), and maternal characteristics (age, parity, BMI, smoking, diabetes, and hypertensive disease). Low TREC was associated with cesarean section before labor (adjusted OR:1.32 [95% CI 1.08–1.62]), male infant sex (aOR:1.60 [1.41–1.83]), preterm birth at 35–36 weeks of gestation (aOR:1.89 [1.21–2.96]) and small for gestational age (aOR:1.67 [1.00–2.79]). Low KREC was associated with male sex (aOR:1.32 [1.15–1.50]), postterm birth at ≥42 weeks (aOR:1.43 [1.13–1.82]) and small for gestational age (aOR:2.89 [1.78–4.69]). Maternal characteristics showed no consistent associations with neonatal levels of either TREC or KREC. Conclusion Cesarean section before labor was associated with lower T-lymphocyte formation, irrespective of maternal characteristics, pregnancy, and neonatal risk factors. The significance of a reduced birth-related surge in lymphocyte formation for future immune function and health remains to be investigated.
Neonatal jaundice is associated with higher risk of attention deficit hyperactivity disorder (ADHD), but it is unclear if the association is influenced by genetic and other familial factors. In this large population-based study, we investigated the association between neonatal jaundice and ADHD while adjusting for familial factors.We linked several Swedish registers to identify all singleton births without congenital malformations between 1992 and 2000 (n = 814 420, including 384 290 full siblings) and followed them up until 2009. We calculated hazard ratios (HRs) for the association between neonatal jaundice and ADHD, adjusting for pregnancy, delivery and neonatal characteristics including prematurity, and parental age and education. We repeated the analyses among siblings to adjust for shared familial factors.At a population level, children treated for neonatal jaundice had an increased risk of ADHD (adjusted HR (aHR): 1.13, 95% CI: 1.05-1.22). In the sibling comparisons, there was no clear association between neonatal jaundice and ADHD (aHR: 1.03, 95% CI: 0.82-1.29).We found no evidence of an independent association between neonatal jaundice and ADHD within siblings in this large population-based study, suggesting that the association is probably influenced by shared familial factors, such as parental genetic and/or lifestyle effects.
125I-labelled fibronectin is shown to bind to both native and denatured collagen immobilized on Sephadex beads in reactions that exhibit different kinetics. The rates of both reactions were enhanced by the presence of heparin or highly sulphated dextran sulphate but not by other glycosaminoglycans or dextran sulphates having low sulphate contents.
Expanded bed adsorption is a new technique using stable homogeneous fluidization for initial recovery of a product from crude fermentation broth. The technique makes it possible to combine clarification, concentration and product capture in one unit operation. This study shows a 144 fold scale-up from laboratory to production scale. The column sizes used are 50 mm I.D. and 600 mm I.D. respectively. Residence time distribution (RTD), the response from an injected step, was used to evaluate the scale up. This reflects the hydrodynamics of the system. Adsorption kinetics was determined from a breakthrough curve of bovine serum albumine and the binding capacity was calculated. The results show that expanded bed adsorption is scaleable from laboratory to production scale with retained properties.
One hundred and nineteen consecutive cases of children with atopic dermatitis aged 4-16 years (73 girls) from a pediatric dermatology outpatient clinic were included in a study of atopic sensitization. Structured interviews and clinical investigations were performed. IgE antibodies to common inhalant allergens, Pityrosporum orbiculare, Candida albicans, Tricophyton rubrum and Staphylococcus aureus were detected. Specific IgE antibodies frequently occurred to pollens, animal epithelia, C. albicans, house dust mites and moulds, whereas specific IgE antibodies to potential skin allergens were less prevalent. Twenty-six children (21.8%) had IgE antibodies to P. orbiculare, 14 (11.8%) to T. rubrum and 3 (2.5%) to S. aureus. Atopic dermatitis in children with one or several RAST positivities was worse, with a more chronic course, higher total eczema score, more frequent distribution in the head-neck-face regions and more itch compared to the children without serum detectable IgE antibodies. Severe itch disturbing nightly sleep was the only clinical feature that characterised P. orbiculare-positive cases. Allergy to P. orbiculare appears to be of little importance in early childhood atopic dermatitis but is likely to carry a poor prognosis.
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