Biomedical subjects

John R Morton

Publications and source records attributed to John R Morton.

4 recordsLinked to original sources

PubMed2003

Asthma exacerbations in children associated with rhinovirus but not human metapneumovirus infection.

Children with asthma were studied during the Southern hemisphere winter and summer of 2001-2002. Human rhinovirus (hRV) was significantly associated (P=.0001) with asthma exacerbations in winter and spring/summer, but not in intervening asymptomatic periods. Although hRV was also found in children with upper respiratory tract infection (URTI) who underwent sampling at the same time, it was present in significantly higher numbers of children with symptomatic asthma (P<.0001). Human metapneumovirus was also found in small numbers of children with URTI, but significantly less frequently in children with asthma.

Adolescent↗

PubMed2003

Mirth-triggered asthma: is laughter really the best medicine?

Mirthful emotions such as laughter and excitement are unrecognized but perhaps important triggers of asthma. Our study aimed to explore the prevalence, mechanisms, and associations of mirth-triggered asthma (MTA) in children. Our MTA prevalence questionnaire was given to 285 children who presented to the Emergency Department of Sydney Children's Hospital (SCH) with an acute episode of asthma. Our MTA profile questionnaire study was a cross-sectional study of 541 children with asthma. The parents completed a questionnaire regarding their child's asthma. In our laughter diary study, diary cards were given to the parents of 21 children with asthma. The diary required details regarding the mirthful stimulus, symptoms of asthma, and recording of peak expiratory flow (PEF) measurements. Of the selected cohort, 31.9% had mirth-triggered asthma. In the cross-sectional study, mirth-triggered asthma was more common: with increasing age (P = 0.02); in those who in the last 3 months had taken more doses of salbutamol (P = 0.005), and who had more wheeze, nocturnal symptoms, and early morning symptoms (P < 0.0005); and in those who reported exercise-induced asthma (P < 0.0005). Laughter was more commonly reported as a trigger than excitement; cough was the most prominent symptom; and symptoms mostly occurred within 2 min of the mirthful stimulus. In the laughter diary study, 59 of 130 recorded events described symptoms of asthma. Mirth while watching a film led to PEF of 73% of baseline, compared with 81% for mirth with exertional play, and 95% for mirth with nonexertional play (P = 0.01). Mirth-triggered asthma is common, and is an indicator of suboptimal asthma control.

Adolescent↗

PubMed2002

Inflammation, infection, and pulmonary function in infants and young children with cystic fibrosis.

Our aim was to study the effect of lower airway infection on clinical parameters, pulmonary function tests, and inflammation in clinically stable infants and young children with cystic fibrosis (CF). To accomplish this goal, a prospective cohort of screened CF patients under 4 years of age were studied, using elective anesthesia and intubation for: passive respiratory mechanics (single breath occlusion passive deflation) and lung volumes (nitrogen washout), under neuromuscular blockade; and bronchoalveolar lavage (BAL) of 3 main bronchi for cytology, cytokine interleukin (IL)-8, and quantitative microbiology. There were 22 children studied, with a mean age of 23.2 months (6.7-44 months). A greater relative risk of lower airway pathogens was associated with prior respiratory admission (3.60, 95% confidence interval [CI] 2.87-4.51), history of asthma (1.75, 95% CI 1.52-2.03), and chronic symptoms (1.50, 95% CI 1.23-1.83), especially wheeze (1.88, 95% CI 1.61-2.19). Lower respiratory pathogens (> or = 10 cfu/ml BAL) were found in 14 out of 22, and greater than 10(5) cfu/ml in 8 out of 22 subjects. The level of pathogens in BAL (log10 cfu/ml) explained 78% of the variability in percent neutrophils and 34% of the variability in IL-8 levels. Pathogen level also correlated with pulmonary function tests of specific respiratory system compliance (r -0.49, p = 0.02) and functional residual capacity over total lung capacity (r 0.49, p = 0.03). We conclude that the presence of pathogens in the lower airways correlated with levels of inflammation, respiratory system compliance, and degree of air trapping.

Bronchoalveolar Lavage Fluid↗

PubMed2002

Relationship between sputum inflammatory markers, lung function, and lung pathology on high-resolution computed tomography in children with cystic fibrosis.

High-resolution computed tomography (HRCT) is a sensitive technique for early visualisation and location of cystic fibrosis (CF) bronchopathology, and has been shown to detect acute reversible and chronic changes. It would be expected to correlate with markers of the underlying pathological processes, such as sputum cytokines and cytology, as well as with pulmonary function tests (PFTs). Our aim was to study the relationship between PFTs, sputum cytology, and sputum cytokine interleukin-8 (IL-8) and HRCT in CF patients. Prospective standardized collection of sputum samples was performed at the time of routine annual high-resolution CT scans. Forced expired volume in 1 sec (FEV(1)) and forced vital capacity (FVC) were recorded. Sputum processing was selective, with dispersal by the three-enzyme technique. IL-8 measurements were by kit assay. HRCT scans were scored by a pediatric radiologist, blinded to clinical condition, using a modified Bhalla score.Forty-three CT scans were performed on 34 children with CF between March 1998 and April 2000. Mean age was 12.3 years (range, 6-21 years), FEV(1) (% predicted) was 67% (range, 23-120%), and mean modified Bhalla score was 11.2 (range, 0-22). Sputum IL-8 concentration (mean, 86; range, 4-150 ng/mL) and total cell count (mean, 31.9 x 10(6)/mL; range, 21.8-42.0 x 10(6)/mL) were high. FEV(1) and FVC correlated with modified Bhalla score (r = -0.66, P < 0.0001 for both), and most individual components of the score, especially mosaic perfusion (r = -0.64, r = -0.61 respectively, P < 0.0001) and extent of bronchiectasis (r = -0.61, P < 0.0001 for both). The combination of these two predicted 58% of the variability in FEV(1) on analysis of variance (P < 0.0001). Sputum total cell count correlated weakly with modified Bhalla score (r = 0.38, P < 0.05) and with FEV(1) and FVC (r = -0.36, P < 0.05; and r = -0.46, P < 0.01). Differential cell counts, cell viability, and IL-8 did not correlate with modified Bhalla scores, or with reversible components such as mucus plugging, centrilobular nodules, or peribronchial thickening. In conclusion, pathological changes on HRCT correlated with lung function but not with sputum markers of inflammation.

Adolescent↗