Asthma: pathophysiology of the bronchial obstruction

Investigation of the optic disc and retinal microvasculature by optical coherence tomography angiography in children with asthma

PURPOSE

To assess the optic disc and retinal microvasculature by optical coherence tomography angiography (OCTA) in asthmatic children.

MATERIALS AND METHODS

Thirty asthmatic children (asthma group) and 30 control age- and sex-matched healthy controls (control group) were included in this cross-sectional study. The asthma group was then divided into two subgroups according to the presence of inhaled steroid use. Demographic findings were noted. Retinal nerve fiber layer (RNFL) thickness and vessel density in different sections of the retina and optic nerve head were analyzed by OCTA.

RESULTS

RNFL thickness for temporal quadrants and flow area for outer retina levels were significantly lower in the asthma group than the control group (72.58 ± 10.99 μm vs 77.73 ± 9.73μm, P = 0.015, and 0.60 ± 0.31mm2 vs. 0.72 ± 0.31mm2, P = 0.047, respectively). However, inside disc vascular densities were significantly higher in the asthma group when compared to controls (55.16% ± 3.71% vs. 52.08% ± 3.79%, P < 0.001). Inside disc vascular densities were also significantly higher, and RNFL thickness for temporal quadrants was significantly lower in the asthmatic patients without steroid use subgroup when compared to others (P < 0.001, P = 0.012, respectively).

CONCLUSION

Lower values of temporal quadrant RNFL, and flow area for outer retina, but higher levels of inside disc vascular density seem to be associated with asthmatic children. OCTA findings in asthmatic children appear to be regardless of inhaled steroid use.

Musculoskeletal dysfunction and pain in adults with asthma

BACKGROUND

The mechanical alterations related to the overload of respiratory muscles observed in adults with persistent asthma might lead to the development of chronic alterations in posture, musculoskeletal dysfunction and pain; however, these changes remain poorly understood.

OBJECTIVE

This study aimed to assess postural alignment, muscle shortening and chronic pain in adults with persistent asthma.

METHODS

This cross-sectional and controlled study enrolled 30 patients with mild (n = 17) and severe (n = 13) persistent asthma. Fifteen non-asthmatic volunteers were also assessed. Asthma was classified by the Global Initiative for Asthma (GINA) guidelines. Postural alignment and muscle shortening were evaluated by head and shoulder positions, chest wall mobility, and posterior (trunk and lower limb) muscle flexibility. In addition, the measures used were previously tested for their reproducibility. Pain complaints were also assessed.

RESULTS

In comparison with non-asthmatic subjects, patients with mild or severe persistent asthma held their head and shoulders more forward and had lower chest wall expansion, decreased shoulder internal rotation, and decreased thoracic spine flexibility. Chronic lower thoracic, cervical, and shoulder pain was significantly increased in patients with mild or severe asthma compared with non-asthmatic subjects (p < 0.05).

CONCLUSION

Adults with persistent asthma have musculoskeletal dysfunction and chronic pain that is independent of the severity of their disease but that might be related to their age at the onset of disease symptoms.

Association between cystic fibrosis transmembrane conductance regulator gene mutations and susceptibility for childhood asthma in Korea

PURPOSE

Classic cystic fibrosis is now known part of cystic fibrosis transmembrane conductance regulator (CFTR)-related disorders. These include a wide spectrum, from multi-system disorders, such as cystic fibrosis, to mono-symptomatic conditions, such as chronic pancreatitis or congenital bilateral absence of the vas deferens. However, respiratory disease is considered typical for the multi system disorder, cystic fibrosis, and is the major cause of morbidity and mortality. The purpose of this study was to evaluate the potential effects of CFTR gene mutations in Korean children with asthma.

MATERIALS AND METHODS

We selected 14 mutations identified in Korea and each of the 48 children with and without asthma were genotyped for the case-control study.

RESULTS

No significant differences were found in genotype and allele frequencies of the 9 polymorphisms observed between the non-asthma and asthma groups. In a haplotype determination based on a Bayesian algorithm, 8 haplotypes were assembled in the 98 individuals tested. However, we also did not find any significant differences in haplotype frequencies between the non-asthma and asthma groups.

CONCLUSION

We have concluded that this study did not show any evidence in support of providing that CFTR genetic variations significantly contribute to the susceptibility of asthma in Korean children.

Are the local blood oxygen level-dependent (BOLD) signals caused by neural stimulation response dependent on global BOLD signals induced by hypercapnia in the functional MR imaging experiment? Experiments of long-duration hypercapnia and multilevel carbon dioxide concentration

BACKGROUND AND PURPOSE

The relationship between the local blood oxygen level-dependent (BOLD) signals caused by neural stimulation (fBOLD) and the global BOLD signals induced by hypercapnia (hBOLD) has not been fully investigated. In this study, we examine whether fBOLD is modulated by hBOLD signals, by means of experiments using a relatively wide range of inhaled carbon dioxide (CO(2)) for a long duration of 5 minutes.

MATERIALS AND METHODS

Ten healthy volunteers were recruited, each undergoing 6 separate experiments by inhaling gas mixtures with different fractions of CO(2) (room air, 3%-7%). Each experiment contained 3 phases, prehypercapnic, hypercapnic, and posthypercapnic, during which boxcar visual stimulus was given. The local fBOLD signals were measured from areas showing activation patterns highly correlated with the visual stimulus paradigm, whereas the global hBOLD signals were measured from areas showing no visual activations. Percentage changes in fBOLD during transient-state hypercapnia and steady-state hypercapnia were both investigated in response to varying degrees of hypercapnic perturbations.

RESULTS

The hBOLD signals increased with increase of inhaled CO(2) fractions. The duration for the hBOLD signals to reach steady state prolonged with increase of inhaled CO(2) fractions. Normalized fBOLD ratio was inversely related to the inhaled CO(2) during steady-state hypercapnia but showed positive association with hBOLD during transient-state hypercapnia.

CONCLUSION

Our study concludes that the steady-state fBOLD signal intensity is dependent on and inversely related to the hBOLD signals. Previous reports documenting independent and additive relationships between hBOLD and fBOLD may likely be due to transient-state observations.

A review of asthma and scuba diving

An increasing number of asthmatics participate in recreational scuba diving. This activity presents unique physical and physiological challenges to the respiratory system. This review addresses the susceptibility of divers with asthma to diving accidents, acute asthmatic attacks, and long-term exacerbation of their disease. Recommendations on fitness to dive with asthma and airway hyperresponsiveness are provided.