T.J. O'Meara

The reduction of rhinitis symptoms by nasal filters during natural exposure to ragweed and grass pollen

Background:  Prototype nasal filters were developed to collect inhaled pollen. This study evaluated the efficacy of the filters for prevention of rhinitis symptoms during acute outdoor pollen exposure.

Detection of inhaled cat allergen

Measuring personal exposure to airborne allergens is important in understanding the association between asthma and allergen exposure. Personal exposure to cat allergen (Fel d 1) is likely to involve a more complex pattern of exposure than indicated by either reservoir dust or long-term air Fel d 1 concentrations. An additional limitation of current methods of air sampling is that the quantity of allergen recovered is low compared with the sensitivity of detection methods. We have developed a passive air sampler worn in each nostril which collects inhaled particles (mainly >5 m) and a method that detects the allergen eluted from each particle. Nasal air samplers were worn by the same individual for 10 min during five replicates of a range of exposure situations in a living room with a cat (31·7 g Fel d 1 per g carpet dust, 569·6 g Fel d 1 per g sofa dust) and in the low-allergen environment of a tea room in the University (2·8 g Fel d 1 per g floor dust). In one sampler, inhaled particles were collected by impaction on to a protein-binding membrane and were immunostained with monoclonal antibodies specific to Fel d 1 (Indoor Biotechnologies, University of Virginia) to detect allergen localised around the inhaled particles. The total number of particles collected and the number of particles containing Fel d 1 were counted, and are expressed as medians. In the other sampler, particles were collected on a non-protein-binding membrane and the eluted allergen measured by ELISA. The detection of Fel d 1 by these methods was compared with a standard personal air sampler (Institute of Occupational Medicine [IOM], Edinburgh) and eluted allergen detected by ELISA. 23 particles containing Fel d 1 were inhaled per nostril, in 10 min, while grooming a cat (figure). In the University tea room, only three particles containing Fel d 1 were collected while wearing clean clothing, but this increased to 20 particles while wearing clothing previously contaminated by exposure to a cat (12·5 g Fel d 1 per g of clothes dust). Cat allergen was detected on 3–19% of all inhaled particles, depending on the activity. By contrast, airborne Fel d 1 was only detected in samples eluted from the nasal filter during the high-exposure activity of cat grooming (three of five samples, maximum ~17·5 ng Fel d 1 per m, assuming an inspiratory flow rate of 10 L/min), while walking in a room with a cat (two of five samples [figure], maximum ~33·3 ng/m), and from the IOM telephoned non-respondents and for each of the different specialties dealing with breast cancer. Almost all these breast-cancer doctors (99%) would generally use tamoxifen in older women with N+ disease, but only half (54%) would do so in younger women with N+ disease. These percentages were smaller (78% and 33%, respectively) for women with node-negative disease (figure, A). Although age and, to a lesser extent, nodal status strongly affect whether adjuvant tamoxifen is prescribed, they had little effect on the usual duration of the regimen used which, for 75% of these doctors, was at least 5 years (figure, B). 12% of clinicians used a longer regimen, however, indicating that a significant minority of these opinion leaders hope for additional benefit from continuing tamoxifen beyond the initial 5 years. That may be justified, but such continuation still needs reliable assessment. As the evidence from the randomised trials of adjuvant tamoxifen continues to evolve, patterns of tamoxifen use will continue to change. The trials, as summarised by the most recent quinquennial worldwide review, now show that, at least for women with some oestrogen-receptor protein detectable on their primary tumour (and for women with no oestrogen-receptor assay done), about 5 years of tamoxifen substantially delays recurrence and improves 10-year survival. This is true not only for older women but also for younger women, irrespective of nodal status. Hence, if the general willingness to use tamoxifen for postmenopausal women with N+ disease were to be extended to those with Ndisease, and to younger women, many more deaths could be avoided. Even for those who receive chemotherapy as part of their adjuvant treatment, addition of tamoxifen confers extra benefit. More than a million women worldwide are now prescribed tamoxifen, but the present heterogeneity in practice is disturbing, particularly with respect to the treatment of younger women (among whom only half of the respondents in our survey would use tamoxifen).

Personal exposure to house dust mite allergen in bed: nasal air sampling and reservoir allergen levels

Background Assessment of personal exposure to dust mite allergen has relied on proxy measures. Only recently has a means to directly measure inhaled allergen particle number become available (the intra‐nasal air sampler).

Adhesive tapes as capturing surfaces in Burkard sampling

Although pressure‐sensitive adhesive tapes appear to offer many advantages over traditional adhesives in sampling with a Hirst‐type spore trap, their particle capturing efficiency has never been documented. In this paper, the particle capture efficiency of four pressure‐sensitive adhesive tapes was compared to the standard vaseline adhesive in the Burkard 7‐day volumetric spore trap. The capture efficiency was assessed at flow rates of 8 and 101 min−1 over a 16 week period with each tape run alongside the standard. Image analysis was used to count and measure the surface area of individual inorganic and organic particles collected onto each tape. Approximately 230,000 individual particles were analysed, the majority of particles collected on both standard and pressure‐sensitive adhesive tapes had a surface area less than 150 μm2 (approximately diameter 14 μm). Capture efficiency was expressed as a percentage of the counts on the standard and classified by particle size and flow rate. For particles < 1000 ...