The effects of allergens in outdoor air on both atopic and nonatopic subjects with airway disease

Contaminant adhesion (aerial/ground biofouling) on the skin of a gecko

In this study, we have investigated the micro- and nano-structuring and contaminant adhesional forces of the outer skin layer of the ground dwelling gecko--Lucasium steindachneri. The lizard's skin displayed a high density of hairs with lengths up to 4 μm which were spherically capped with a radius of curvature typically less than 30 nm. The adhesion of artificial hydrophilic (silica) and hydrophobic (C18) spherical particles and natural pollen grains were measured by atomic force microscopy and demonstrated extremely low values comparable to those recorded on superhydrophobic insects. The lizard scales which exhibited a three-tier hierarchical architecture demonstrated higher adhesion than the trough regions between scales. The two-tier roughness of the troughs comprising folding of the skin (wrinkling) limits the number of contacting hairs with particles of the dimensions used in our study. The gecko skin architecture on both the dorsal and trough regions demonstrates an optimized topography for minimizing solid-solid and solid-liquid particle contact area, as well as facilitating a variety of particulate removal mechanisms including water-assisted processes. These contrasting skin topographies may also be optimized for other functions such as increased structural integrity, levels of wear protection and flexibility of skin for movement and growth. While single hair adhesion is low, contributions of many thousands of individual hairs (especially on the abdominal scale surface and if deformation occurs) may potentially aid in providing additional adhesional capabilities (sticking ability) for some gecko species when interacting with environmental substrates such as rocks, foliage and even man-made structuring.

Time for new methods for avoidance of house dust mite and other allergens

Asthma is a common disease in which environmental exposures and lifestyle factors play critical roles in expression and symptoms. Recommended methods for reducing exposure to domestic allergens as a component of asthma and rhinitis management have changed little over the last 30 years. The data that implementation of these provides clinical benefit are inconsistent. We contend that current methods are ineffective at reducing chronic personal exposure. More effective strategies can be developed based on understanding when people are exposed, the sources of this exposure and the activities associated with this exposure. Developing new methods should be founded on understanding the aerodynamic behavior of particles, their aerosolization, removal from surfaces, and the complex relationships between exposures and clinical outcomes. It will also require developing better proxy measures of chronic exposure, identifying markers for the sub-set of people who benefit, and integrating this with strategies addressing other domestic exposures and lifestyle factors.

Serum total immunoglobulin E is a surrogate of atopy in adult-onset asthma: a longitudinal study

BACKGROUND

Studies have shown that serum total immunoglobulin E (IgE) levels are higher in asthmatics. However, the role of the serum total IgE level, independently from atopy, in adult asthma is not understood. We studied the associations between serum total IgE, the number of sensitizations and the sum of specific IgEs and new-onset asthma using longitudinal data from the European Community Respiratory Health Survey.

METHODS

Serum total and specific IgE to 4 common inhalant allergens were measured at baseline in 9,175 participants, with a follow-up of 9 years. Individuals with asthma history and/or asthma symptoms were excluded. Atopy was defined as the presence of at least one specific IgE ≥0.35 kU/l. Total and specific IgEs were regressed against new-onset asthma using multivariate logistic regression with a random intercept for the study centre.

RESULTS

Two hundred and ninety-seven participants had developed asthma during follow-up (incidence rate 5.7 per 1,000 person-years). A 10% higher level of total IgE was associated with a 12% increased risk of new-onset asthma (p = 0.005). However, after adjustment for the number of positive specific IgEs [odds ratio (OR) for multiple sensitization 1.74, 95% confidence interval (CI) 1.05–2.88] and the sum of allergenspecific IgEs (OR 1.18, 95% CI 1.00–1.40), the association between total IgE and asthma disappeared (OR 1.00, 95% CI 0.91–1.10). Seventeen percent of new-onset asthma cases could be attributed to atopy, and this estimate was not largely modified when the total IgE level was simultaneously taken into account.

CONCLUSIONS

After taking into account the number and intensity of 4 specific IgEs, the serum total IgE level was not associated with new-onset asthma in adults.

Indoor particulate matter increases asthma morbidity in children with non-atopic and atopic asthma

BACKGROUND

Compared with atopic asthma, fewer environmental modifications are recommended for non-atopic asthma in children.

OBJECTIVE

To better understand the role of indoor pollutants in provoking non-atopic asthma, we investigated the effect of in-home particulate matter on asthma symptoms among non-atopic and atopic children living in inner-city Baltimore.

METHODS

A cohort of 150 children ages 2 to 6 years with asthma underwent home environmental monitoring for 3-day intervals at baseline, 3, and 6 months. Children were classified as non-atopic if they were skin test negative to a panel of 14 aeroallergens. Caregivers completed questionnaires assessing symptoms and rescue medication use. Longitudinal data analysis included regression models with generalized estimating equations.

RESULTS

Children were primarily African American from lower socioeconomic backgrounds and spent most of their time in the home. Thirty-one percent were non-atopic, and 69% were atopic. Among non-atopic and atopic children, increased in-home fine (PM2.5) and coarse (PM2.5-10) particle concentrations were associated with significant increases in asthma symptoms and rescue medication use ranging from 7% (95% confidence interval [CI], 0-15) to 14% (95% CI, 1-27) per 10 μg/m(3) increase in particle concentration after adjustment for confounders.

CONCLUSIONS

In-home particles similarly cause increased symptoms of asthma in non-atopic and atopic children. Environmental control strategies that reduce particle concentrations may prove to be an effective means of improving asthma outcomes, especially for non-atopic asthma, for which there are few environmental control practice recommendations.

Epidemiology of stress and asthma: from constricting communities and fragile families to epigenetics

Several epidemiologic frameworks, exemplified through extant research examples, provide insight into the role of stress in the expression of asthma and other allergic disorders. Biologic, psychological, and social processes interact throughout the life course to influence disease expression. Studies exploiting a child development framework focus on critical periods of exposure, including the in utero environment, to examine the influence of stress on disease onset. Early stress effects that alter the normal course of morphogenesis and maturation that affect both structure and function of key organ systems (eg, immune, respiratory) may persist into adult life underscoring the importance of a life course perspective. Other evidence suggests that maternal stress influences programming of integrated physiologic systems in their offspring (eg, neuroendocrine, autonomic, immune function) starting in pregnancy; consequently stress effects may be transgenerational. A multilevel approach that includes an ecological perspective may help to explain heterogeneities in asthma expression across socioeconomic and geographic boundaries that to date remain largely unexplained. Evolving studies incorporating psychological, behavioral, and physiologic correlates of stress more specifically inform underlying mechanisms operating in these critical periods of development. The role of genetics, gene by environment interactions, and epigenetic mechanisms of gene expression have been sparsely examined in epidemiologic studies on stress and asthma although overlapping evidence provides proof of concept for such studies in the future.

Fouling of nanostructured insect cuticle: adhesion of natural and artificial contaminants

The adhesional properties of contaminating particles of scales of various lengths were investigated for a wide range of micro- and nanostructured insect wing cuticles. The contaminating particles consisted of artificial hydrophilic (silica) and spherical hydrophobic (C(18)) particles, and natural pollen grains. Insect wing cuticle architectures with an open micro-/nanostructure framework demonstrated topographies for minimising solid-solid and solid-liquid contact areas. Such structuring of the wing membranes allows for a variety of removal mechanisms to contend with particle contact, such as wind and self-cleaning droplet interactions. Cuticles exhibiting high contact angles showed considerably lower particle adhesional forces than more hydrophilic insect surfaces. Values as low as 3 nN were recorded in air for silica of ~28 nm in diameter and <25 nN for silica particles 30 μm in diameter. A similar adhesional trend was also observed for contact with pollen particles.

Risk factors of new-onset asthma in adults: a population-based international cohort study

BACKGROUND

The occurrence of new-onset asthma during adulthood is common, but there is insufficient understanding of its determinants including the role of atopy.

OBJECTIVE

To assess the risk factors for the development of new-onset asthma in middle-aged adults and to compare them according to atopy.

METHODS

A longitudinal analysis of 9175 young adults who participated in two surveys of the European Community Respiratory Health Survey (ECRHS) conducted 9 years apart.

FINDINGS

We observed 179 cases of new-onset asthma among 4588 participants who were free of asthma and reported at the beginning of the follow-up that they had never had asthma (4.5 per 1000 person-years). In a logistic regression, the following risk factors were found to increase the risk of new-onset asthma: female gender (OR: 1.97; 95% confidence interval (CI): 1.38, 2.81), bronchial hyperresponsiveness (3.25; 2.19, 4.83), atopy (1.55; 1.08, 2.21), FEV(1) < 100 % predicted (1.87; 1.34, 2.62), nasal allergy (1.98;1.39,2.84) and maternal asthma (1.91; 1.13; 3.21). Obesity, respiratory infections in early life and high-risk occupations increased the risk of new-onset asthma although we had limited power to confirm their role. Among the atopics, total IgE and sensitization to cat were independently related to the risk of new-onset asthma. The proportion of new-onset asthma attributable to atopy varied from 12% to 21%.

CONCLUSION

Adults reporting that they had never had asthma were at a substantial risk of new-onset asthma as a result of multiple independent risk factors including lung function. Atopy explains a small proportion of new-onset adult asthma.

Minor psychiatric disorders in mothers and asthma in children

OBJECTIVE

Recent studies have shown that asthma represents a major health issue not only in children of developed countries but also in urban centers in some middle-income countries. Brazil has one of the highest prevalences of asthma worldwide. Recently, interest has grown in the relationship between psychosocial factors and asthma. This article examines the relationship between maternal mental disorders and the prevalence of asthma in low-income children from an inner city area of Salvador in the state of Bahia, Brazil, and is part of the SCAALA program (Social Change, Allergy and Asthma in Latin America).

PATIENTS AND METHODS

A total of 1,087 children between the ages of 5 and 12 were investigated, together with their mothers. The mothers' mental health was evaluated using the SRQ-20, an instrument for the psychiatric screening of minor psychiatric disorders (depression, anxiety and somatic complaints). The prevalence of asthma was investigated using the ISAAC survey, a standardized, validated questionnaire for asthma and other allergic diseases. Cases were defined as asthma if the patient reported having had wheezing in the previous 12 months in addition to at least one of the following: having asthma, wheezing while exercising, waking during the night because of wheezing, or having had at least four episodes of wheezing in the previous 12 months. Atopy was defined as a positive skin prick test to allergens.

RESULTS AND CONCLUSION

The presence of minor psychiatric disorders in the mothers was significantly associated with the presence of asthma in the children, and this association was consistent with all forms of asthma, irrespective of whether it was atopic or nonatopic. Future studies should be carried out to further investigate this association and the potential biological mechanisms involved. Programs for asthma control should include strategies for stress reduction and psychological support for the families of asthmatic children.