Pooled analysis of recent studies on magnetic fields and childhood leukaemia

BACKGROUND: Previous pooled analyses have reported an association between magnetic fields and childhood leukaemia. We present a pooled analysis based on primary data from studies on residential magnetic fields and childhood leukaemia published after 2000. METHODS: Seven studies with a total of 10 865 cases and 12 853 controls were included. The main analysis focused on 24-h magnetic field measurements or calculated fields in residences. RESULTS: In the combined results, risk increased with increase in exposure, but the estimates were imprecise. The odds ratios for exposure categories of 0.1-0.2 mu T, 0.2-0.3 mu T and >= 0.3 mu T, compared with <0.1 mu T, were 1.07 (95% Cl 0.81-1.41), 1.16 (0.69-1.93) and 1.44 (0.88-2.36), respectively. Without the most influential study from Brazil, the odds ratios increased somewhat. An increasing trend was also suggested by a nonparametric analysis conducted using a generalised additive model. CONCLUSIONS: Our results are in line with previous pooled analyses showing an association between magnetic fields and childhood leukaemia. Overall, the association is weaker in the most recently conducted studies, but these studies are small and lack methodological improvements needed to resolve the apparent association. We conclude that recent studies on magnetic fields and childhood leukaemia do not alter the previous assessment that magnetic fields are possibly carcinogenic. British Journal of Cancer (2010) 103, 1128-1135. doi: 10.1038/sj.bjc.6605838 www.bjcancer.com (c) 2010 Cancer Research UK

Pulmonary Surfactant in Respiratory Syncytial Virus Bronchiolitis: The Role in Pathogenesis and Clinical Implications

Respiratory syncytial virus (RSV) bronchiolitis is the leading cause of lower respiratory tract infection, and the most frequent reason for hospitalization among infants throughout the world. In addition to the acute consequences of the disease, RSV bronchiolitis in early childhood is related to further development of recurrent wheezing and asthma. Despite the medical and economic burden of the disease, therapeutic options are limited to supportive measures, and mechanical ventilation in severe cases. Growing evidence suggests an important role of changes in pulmonary surfactant content and composition in the pathogenesis of severe RSV bronchiolitis. Besides the well-known importance of pulmonary surfactant in maintenance of pulmonary homeostasis and lung mechanics, the surfactant proteins SP-A and SP-D are essential components of the pulmonary innate immune system. Deficiencies of such proteins, which develop in severe RSV bronchiolitis, may be related to impairment in viral clearance, and exacerbated inflammatory response. A comprehensive understanding of the role of the pulmonary surfactant in the pathogenesis of the disease may help the development of new treatment strategies. We conducted a review of the literature to analyze the evidences of pulmonary surfactant changes in the pathogenesis of severe RSV bronchiolitis, its relation to the inflammatory and immune response, and the possible role of pulmonary surfactant replacement in the treatment of the disease. Pediatr Pulmonol. 2011; 46:415-420. (c) 2010 Wiley-Liss, Inc.

Circulating renin-angiotensin system and catecholamines in childhood: is there a role for birthweight?

There have been only a few reports on the sympathoadrenal and renin-angiotensin systems in children of small gestational age. The purpose of the present study was to investigate plasma levels of ACE (angiotensin-converting enzyme) activity, angiotensin and catecholamines in 8- to 13-year-old children and to determine whether there are correlations between the components of these systems with both birthweight and BP (blood pressure) levels. This clinical study included 66 children (35 boys and 31 girls) in two groups: those born at term with an appropriate birthweight [AGA (appropriate-for-gestational age) group, n = 31] and those born at term but with a small birthweight for gestational age [SGA (small-for-gestational age) group, n = 35]. Concentrations of angiotensin, catecholamines and ACE activity were determined in plasma. Circulating noradrenaline levels were significantly elevated in SGA girls compared with AGA girls (P = 0.036). In addition, angiotensin 11 and ACE activity were higher in SGA boys (P = 0.024 and P = 0.050 respectively). There was a significant association of the circulating levels of both angiotensin 11 and ACE activity with BP levels in our study population. Although the underlying mechanisms that link restricted fetal growth with later cardiovascular events are not fully understood, the findings in the present study support the link between low birthweight and overactivity of both sympathoadrenal and renin-angiotensin systems into later childhood.