The oligomerisation states of MBP-BLV-hairpin and mutant derivatives were examined by gel filtration using a Superdex 200 column equilibrated with MBP elution buffer. Fractions containing the trimeric species were retained. To assess the thermostability of the trimers, samples from these fractions were re-run over the column either without heat treatment or with heat treatment at the temperature specified for 5 min, followed by cooling for 2 min on ice. The areas under the peaks observed were calculated, and the area of the peak corresponding to the aggregate was expressed as a percentage of the total area under both this peak and the peak corresponding to the trimer.  Tracheostomy and mechanical ventilation weaning in children affected by respiratory virus according to a weaning protocol in a pediatric intensive care unit in Argentina: an observational restrospective trial We describe difficult weaning after prolonged mechanical ventilation in three tracheostomized children affected by respiratory virus infection. Although the spontaneous breathing trials were successful, the patients failed all extubations. Therefore a tracheostomy was performed and the weaning plan was begun. The strategy for weaning was the decrease of ventilation support combining pressure control ventilation (PCV) with increasing periods of continuous positive airway pressure + pressure support ventilation (CPAP + PSV) and then CPAP + PSV with increasing intervals of T-piece. They presented acute respiratory distress syndrome on admission with high requirements of mechanical ventilation (MV). Intervening factors in the capabilities and loads of the respiratory system were considered and optimized. The average MV time was 69 days and weaning time 31 days. We report satisfactory results within the context of a directed weaning protocol. During winter in 2009, Argentina as well as several other countries in the world, was affected by Influenza A H1N1 pandemic [1] .