Neonatal sepsis and later development of atopy

Background: The role of infections on the development of atopy is still widely debated. We aimed to evaluate the effects of neonatal severe sepsis and consequent antibiotic treatment on the development of atopy and allergic diseases. Material and methods: A retrospective enrolment at school age of children with a clear history of neonatal sepsis (NS) was performed from registers of neonatal intensive care units. A normal control was assigned to each patient with sepsis. Thirty six cases with sepsis (18 males, 18 females) and 36 controls (21 males, 15 females) were selected (8.5±3.6 yrs). Physical examination and lung function evaluation were performed. Atopic status was verified by blood eosinophil count, total IgE serum level and skin prick tests (SPT). Results: SPT positivity for at least one allergen was present in 30% of subjects in both groups. No difference for all investigated parameters between groups and no influence by other factors such as familiarity or gender was observed. No correlation was associated to NS history. Conclusions: Neonatal sepsis, even if clinically severe and dramatic, could represent an event too limited and really precocious in life to influence the development of immune response. Furthermore, other factors, besides infections, may influence the atopic future of newborns (AU)

Intermolecular interactions as controlling factor for water sorption into polymer membranes.

A multidisciplinary approach was used for delineating the mechanisms controlling water sorption into modified block co-poly-(ether/amide) (PEBAX) membranes. In particular, incorporation of aromatic sulfonamide (KET) into the polymer matrix led to a nonlinear increase of water sorption in the membrane. The modification in sorption was accompanied by a nonlinear behavior in membrane surface energies. Infrared analysis revealed a different availability and accessibility of free polar groups supporting the formation of hydrogen bonding as a function of modifier concentration. A combination of both experimental and theoretical procedures was used to analyze the molecular processes of water sorption on PEBAX membranes. Molecular dynamics (MD) and quantum chemical (QC) calculations demonstrated that the formation of KET-KET dimers in the polymeric matrix led to a decrease in the interaction energy between water and modifiers. In addition, no variations in the dipole moments of water-dimer structures were found in comparison to a single KET and water-KET molecule. The formation of water-dimer complexes at higher concentration of modifier decreases the number of the dipole moment, thus preventing the polarization of polymer chains.