Gerald A. Bucholtz

House dust mite allergy in Florida. Mite survey in households of mite-sensitive individuals in Tampa, Florida.

This study evaluated the prevalence of positive house dust mite skin tests in a population of atopic individuals and identified the mite species present in mattress and house dust samples in homes of the Tampa Bay area. Four hundred consecutive individuals were evaluated for respiratory complaints and skin tested with standardized extracts of Dermatophagoides pteronyssinus (Dp) and Dermatophagoides farinae (Df). Two hundred forty individuals (60%) had a positive skin test to the mite extracts. Dust samples were collected in 40 homes of mite-allergic individuals and analyzed by light microscopy. Mite species were found in 53 of the 60 dust samples (20 mattresses and 40 carpets). Mite numbers ranged from 110-6200 mites/g of mattress dust and from 120-5500 mites/g of carpet dust. Eleven different mite species were identified and Blomia tropicalis (Bt), not previously identified in the United States, was found in 30% of the samples. Dp and Df wee the predominant species. These observations suggest that house dust mite allergy is common in the Tampa Bay area and that the house dust mite fauna comprises several mite species besides Dp and Df. Prospective studies in progress are designed to confirm the role of different mite species in house dust mite allergy.

A dose-response study of the bronchodilator action of azelastine in asthma

Azelastine is an orally effective inhibitor of mediator activity in allergic reactions and has also been demonstrated to have bronchodilator activity. In this randomized, double-blind, placebo-controlled, multicenter study, 150 patients, aged 12 to 60 years, with moderate to severe asthma, received a single oral dose of 2, 4, 8, 12, or 16 mg of azelastine or placebo. Theophylline was stopped 24 hours and other bronchodilators at least 8 hours before the study day. Patients were evaluated for 8 hours after dose by spirometry and were monitored for adverse effects. All doses of azelastine produced bronchodilation with 4 mg greater than 2 mg greater than placebo; higher doses did not increase magnitude or duration of effect. We conclude that azelastine produces significant bronchodilation of long duration. The optimal dose appears to be 4 mg for adolescent and adult patients with asthma.

PCR analysis of nasal polyps, chronic sinusitis, and hypertrophied turbinates for DNA encoding bacterial 16S rRNA.

Background Nasal polyps are considered to result from chronic inflammation, but the initial or persisting stimulus for the inflammation is not known. A variety of bacteria and fungi have been cultured from nasal polyps, but ∼35% have sterile cultures. Previously, Mycoplasma pneumoniae–specific DNA was detected in human nasal polyps using polymerase chain reaction (PCR) techniques, suggesting M. pneumoniae as a causative agent in the etiology of nasal polyps. Methods In this study, we tested for the presence of bacterial DNA in nasal polyps resected from 40 patients, in nasal mucosa membrane from 9 patients undergoing turbinectomy for hypertrophy, and in sinus mucosa membrane from 6 patients undergoing endoscopic surgery for chronic sinusitis. Tissue DNA was extracted and analyzed by PCR using M. pneumoniae specific primers for DNA that encode the 16S rRNA gene in 41 specimens (31 polyps, 6 turbinates, and 4 sinus), and by consensus sequence-based PCR using broad range primers for most eubacterial DNA encoding the 16S rRNA gene in 38 specimens (26 polyps, 7 turbinates, and 5 sinuses). Results Only two samples were positive for bacterial DNA encoding 16S rRNA: Streptococcus sp. DNA was isolated from one polyp specimen and Pseudomonas aeruginosa DNA was isolated in one maxillary sinusitis specimen. No evidence of M. pneumoniae–specific DNA encoding 16S rRNA was found in any of the tissues. Conclusions This study suggests that chronic bacterial infection is not a major component of nasal polyp etiology.

Melaleuca tree and respiratory disease.

BACKGROUND The role of Melaleuca quinquenervia tree as a source of allergen(s) and respiratory irritant(s) is controversial. OBJECTIVE Determine whether Melaleuca tree pollen or odor is medically important. METHODS A 2-year aeroallergen survey and skin test (ST) results of 1,017 subjects were reviewed. Sixteen subjects were selected based on positive Melaleuca pollen extract (MPE) STs. Double-blind nasal challenges with MPE were performed on six subjects. Single-blind bronchial challenges with MPE were performed on four. To evaluate the irritant effect, 11 subjects received 34 different Melaleuca odor challenges (blossoms, bark, and leaves) through a closed system for up to 30 minutes. Four inhaled an odor from cajeput oil (derived from Melaleuca leaves) for 1 hour. Spirometry was performed before and after odor challenges. Radioallergosorbent test using MPE was compared with MPE STs in 15 subjects. RESULTS The aeroallergens survey revealed insignificant numbers of Melaleuca pollen. Ninety-seven of 1,017 subjects were a 2+ or greater intradermal MPE ST. One of 6 double-blind nasal challenges and 1 of 4 single-blind bronchial challenges using MPE were positive in subjects with positive MPE STs. All 38 odor challenges with blossoms, bark, leaves, and cajeput oil were nonreactive. The MPE radioallergosorbent test correlated with MPE ST results. CONCLUSIONS The Melaleuca tree is not a significant source of aeroallergen. The Melaleuca odor is not a respiratory irritant. MPE antigen(s) has been shown to cross-react with pollen extracts from a proven aeroallergen (Bahia grass pollen) possibly explaining the few cases of positive MPE STs with positive nasal/bronchial challenges.

The cystic fibrosis conductance regulator gene exon sequence is normal in a patient with edematous eosinophilic nasal polyps.

Nasal polyps are the most common mass lesions found in the nose and their etiology is unknown. Nasal polyps from cystic fibrosis (CF) patients are histologically distinct from nasal polyps from patients without CF. It has been suggested that a mutation (G551D) of the cystic fibrosis transmembrane conductance regulator (CFTR) gene may play a role in nasal polyp formation in patients without CF. To investigate the possibility that this or other CFTR gene exon mutations are required for nasal polyp formation, the CFTR gene exons were sequenced from peripheral blood DNA derived from an adult patient with edematous eosinophilic nasal polyps and no personal or family history of CF. No mutations or deletions were identified in any of the CFTR exons. A single polymorphism (A or G) was found in exon 10, base pair 1540, amino acid 470. This polymorphism was detected in 11 of 16 subjects (69%) with edematous eosinophilic nasal polyps and 10 of 21 normal subjects (48%) without nasal polyps and was not statistically significant (p = 0.316). These results demonstrate that mutations of the CFTR coding region are not a prerequisite for the formation of edematous eosinophilic nasal polyps.