Carbon in airway macrophages from children with asthma.

BACKGROUND: Airway macrophage (AM) phagocytosis is impaired in severe asthma. Prostaglandin (PG) E2 and D2 are increased in severe asthma and suppress AM phagocytic function in vitro. In this study, we sought evidence for PG-mediated impairment of phagocytosis of inhalable carbonaceous particulate matter (PM) by AM in children with severe asthma compared with mild asthmatics and healthy controls. METHODS: AM were obtained from children with asthma and healthy controls using induced sputum. AM carbon area (µm(2)) was assessed by image analysis. In a subgroup of asthmatics, urinary PGE2 and PGD2 metabolites were measured by high-performance liquid chromatography, and PM exposure at the home address was modelled. Phagocytosis of PM by human monocyte-derived macrophages and rat AM was assessed in vitro by image analysis. RESULTS: AM carbon was 51% lower in children with moderate-to-severe asthma (n=36) compared with mild asthmatics (n=12, p<0.01) and healthy controls (n=47, p<0.01). There was no association between modelled PM exposure and AM carbon in 33 asthmatics who had a urine sample, but there was an inverse association between AM carbon and urinary metabolites of PGE2 and D2 (n=33, rs=-0.40, p<0.05, and rs=-0.44, p<0.01). PGE2 10(-6) M, but not PGD2 10(-6) M, suppressed phagocytosis of PM10 by human macrophages in vitro (p<0.05 vs control). PGE2 10(-6) M also suppressed phagocytosis of PM10 by rat AM in vitro (p<0.01 vs control). CONCLUSIONS: Phagocytosis of inhaled carbonaceous PM by AMs is impaired in severe asthma. PGE2 may contribute to impaired AM phagocytic function in severe asthma.

Ambulatory intravenous antibiotic therapy for children with preseptal cellulitis.

OBJECTIVE: This study aimed to compare the use of outpatient ambulatory care versus admission for intravenous antibiotics in the management of preseptal cellulitis. METHODS: This is a retrospective consecutive cohort study of children younger than 16 years presenting to an Inner London Paediatric Emergency Department with signs and symptoms of preseptal cellulitis. RESULTS: A total of 94 cases were identified during a 17-month period. Of them, 30 children were prescribed oral antibiotics. One child did not receive treatment. Of the 63 children prescribed with intravenous antibiotics, 42 were managed on an ambulatory basis and 21 were admitted. There was no significant difference in duration of treatment in days between those on ambulatory management and those admitted (2.79 ± 0.8 vs 2.76 ± 1.9, P = 0.94) or in the rate of complications. The net cost saving was $205,924 (£131,065; &OV0556;147,578) overall, equal to $4900 (£3120; &OV0556;3513) per patient. CONCLUSIONS: Ambulatory intravenous antibiotics with daily review are a safe and cost-effective alternative to inpatient admission in simple preseptal cellulitis for children in our population who require parenteral antibiotics.

Carbon loading in airway macrophages as a biomarker for individual exposure to particulate matter air pollution - A critical review.

Exposure to particulate matter (PM) is associated with adverse health effects, including chronic lung diseases, lung cancer and cardiovascular disease. Personal exposure varies depending on the generation of particles locally, background levels, activity patterns and meteorology. Carbon loading in airway macrophages (AM) is a novel marker to assess personal exposure to combustion-derived particles. This review summarizes the published evidence and describes the validity and reliability of this marker with a focus on the technical aspects. Carbon loading in AM is reported in nine published studies assessing personal exposure to particulate air pollution. The carbon content is quantified by image analysis and is suggested to be suited to assess cumulative exposures. While there is some variation in study technique, these studies each indicate that internal AM carbon reflects either external exposure or important health effects. However, some uncertainty remains regarding potentially confounding materials within particles, the time frame of exposures that this technique reflects, and the optimal strategy to accurately quantify AM carbon. These aspects need to be clarified or optimized before applying this technique in larger populations.

Pseudomonas aeruginosa in cystic fibrosis: pathogenesis and new treatments.

Pseudomonas aeruginosa is the most problematic organism in patients with cystic fibrosis. This article reviews its pathogenic mechanisms, with particular relevance to the pathophysiology of the cystic fibrosis airway, and recent advances in therapeutic approaches.