Population pharmacokinetics of 25-hydroxy vitamin D in children with asthma
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OBJECTIVES: Asthma and vitamin D deficiency are widespread in the pediatric and adolescent population. The aim of this study was to develop a population pharmacokinetic (PPK) model and to evaluate the most important factors that can significantly affect clearance of 25-hydroxy vitamin D in asthmatic children using PPK analysis. MATERIALS AND METHODS: The study population included school children and adolescents from 7 to 18 years of age of both sexes. PPK analysis was performed by non-linear mixed-effects modeling (NONMEM), and 19 covariates were assessed. Goodness-of-fit plots, validation set and bootstrap analysis were conducted to confirm predictive performance of the final model. RESULTS: A total of 60 patients were included in the basic NONMEM data set for PPK modeling with a mean age of 10.2 years and body weight of 41.3 kg. The final pharmacokinetic model for the clearance of 25-hydroxy vitamin D included as covariates intake of vitamin D from foods (DD), hereditary predisposition to asthma (HPA) and the ratio of forced expiratory volume in first second and forced vital capacity (FEV1/FVC ratio). A validation set consisted of 14 separate patients with similar characteristics to the basic data set. The final model was confirmed by internal and external validation and also through goodness-of-fit plots. CONCLUSION: These results could be of help for individualization of vitamin D supplementation doses in this vulnerable population.
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Diaphragmatic defect or pulmonary sequestration in a five-year-old boy.

This case report presents a 5-year-old boy with diaphragmatic defect with a tardy clinical manifestation. The findings of chest x-ray and chest CT scan were seen by pediatricians and radiologists as interstitial pneumonia and suspected pulmonary sequestration, pediatric surgeons saw it as a benign teratoma and during surgery a muscular defect of hemidiaphragm right was found. This case emphasize the rarity of diaphragmatic hernia in children of older age, the importance of "accented" clinical suspicion based on the maintenance of signs of mild respiratory failure, the need for additional radiological tests and surgery with the aim to diagnose this abnormality and "successfulness" of prenatal ultrasound examination.