Asthma Sensitization Research Articles

Increased bronchovascular permeability after allergen exposure in sensitive asthmatics.

To investigate the possibility that an increase in bronchovascular permeability is associated with allergen exposure in sensitive asthmatics we evaluated the amounts of serum proteins in bronchoalveolar lavage (BAL) effluents before and after local challenge with allergen. After exposure of sensitive asthmatic airways (n = 15) to allergen significant increases in total protein compared with controls were observed: 0.08 +/- 0.01 mg/ml in control airways and 0.13 +/- 0.02 mg/ml in challenged airways; P less than 0.05. The greatest changes induced by allergen exposure involved small-molecular-weight proteins (less than 345,000) and an inverse correlation was observed between log molecular weight and percent increase in the concentrations of the specific proteins; r = -0.61. BAL-serum distribution coefficients of serum proteins in airway fluids reflected a greater diffusability of low-molecular-weight proteins immediately after allergen exposure. We also evaluated the movement of serum proteins into lung after local allergen exposure using intravenously administered 99mTc-albumin (n = 10) and found an immediate 3.8-fold increase in amounts of radioactive albumin in allergen exposed airways compared with airways exposed to diluent. Most of the radioactivity was recovered in the first 5 ml of aliquot withdrawn, suggesting a marked increase in the permeability of the bronchial (large airway) vascular-epithelial membrane. An increase in serum proteins was also observed in BAL fluid of asthmatics 2-4 h after aerosol challenge (n = 4), including all proteins in the molecular weight range 45,000-900,000. These studies suggest that allergen exposure in sensitive asthmatics causes an acute increase in bronchovascular permeability to serum proteins.

Adverse reactions to food additives.

There are thousands of agents that are intentionally added to the food that we consume. These include preservatives, stabilizers, conditioners, thickeners, colorings, flavorings, sweeteners, antioxidants, etc. etc. Yet only a surprisingly small number have been associated with hypersensitivity reactions. Amongst all the additives, FD&C dyes have been most frequently associated with adverse reactions. Tartrazine is the most notorious of them all; however, critical review of the medical literature and current Scripps Clinic studies would indicate that tartrazine has been confirmed to be at best only occasionally associated with flares of urticaria or asthma. There is no convincing evidence in the literature of reactivity to the other azo or nonazo dyes. This can also be said of BHA/BHT, nitrites/nitrates and sorbates. Parabens have been shown to elicit IgE mediated hypersensitivity reactions when used as pharmaceutical preservatives; however, as with the other additives noted above, ingested parabens have only occasionally been associated with adverse reactions. MSG, the cause of the 'Chinese restaurant syndrome' has only been linked to asthma in one report. Sulfiting agents used primarily as food fresheners and to control microbial growth in fermented beverages have been established as the cause of any where from mild to severe and even fatal reactions in at least 5% of the asthmatic population. Other reactions reported to follow sulfite ingestion include anaphylaxis, gastro intestinal complaints and dermatological eruptions. The prevalence of these non asthmatic reactions is unknown. The mechanism of sulfite sensitive asthma is also unknown but most likely involves hyperreactivity to inhale SO2 in the great majority of cases; however, there are reports of IgE mediated reactions and other sulfite sensitive asthmatics have been found with low levels of sulfite oxidase; necessary to oxidize endogenous sulfite to sulfate.

Effect of nedocromil sodium on histamine airway responsiveness in grass‐pollen sensitive asthmatics during the pollen season

We examined the effect of nedocromil sodium on histamine airway responsiveness in twelve grass-pollen sensitive patients during the 1984 pollen season. The study was a randomized double-blind crossover comparison of nedocromil sodium administered by a pressurized aerosol (4 mg b.d.) with placebo. Crossovers were made at 14-day intervals throughout 8 weeks of the grass pollen season. Histamine airway responsiveness was assessed twice before the pollen season and at the end of each 14-day treatment period. Results were expressed as the provocation concentration (PC) producing a 10% fall in FEV1 (PC10 FEV1) and a 40% fall in flow at 30% of the vital capacity (PC40 V30(P]. During the pollen season all patients developed hay fever and seven had symptoms of asthma. The observed lowest values of PC10 FEV1 and PC40 V30(P) during the placebo treatment periods were significantly lower than mean preseasonal values although not significantly lower than theoretical expected values. Geometric means PC10 FEV1 and PC40 V30(P) were significantly higher during nedocromil sodium treatment compared with placebo. These results indicate that nedocromil sodium has a small but statistically significant effect reducing histamine airway responsiveness in grass-pollen sensitive patients during the pollen season.

Bronchial hyperreactivity to histamine in aspirin sensitive asthmatics: relationship to aspirin threshold and effect of aspirin desensitisation.

Twenty seven aspirin sensitive asthmatic patients were studied to determine the relationship between non-specific bronchial responsiveness to inhaled histamine and the degree of sensitivity to aspirin (aspirin threshold dose). No correlation was found between provocative concentration of histamine (PC20H) and aspirin threshold dose. In 11 patients the influence of aspirin desensitisation on bronchial reactivity to inhaled histamine was examined. Mean PC20H measured the day after the patients were desensitised to 600 mg of aspirin did not change significantly from the values before desensitisation. These observations suggest that sensitivity to aspirin and non-specific bronchial hyperreactivity in asthmatic patients are independent phenomena.

162 Reactivity to inhaled Bronkosol R in sulfite sensitive asthmatics (SSA)

162 Reactivity to inhaled Bronkosol R in sulfite sensitive asthmatics (SSA)

COMPARISON OF NORMAL AND ASTHMATIC SUBJECTS' RESPONSES TO SULPHATE POLLUTANT AEROSOLS

Epidemiological studies support an association between elevated levels of sulfates and acute respiratory disease. To determine if these pollutants produce airway hyperreactivity, 16 normal and 17 asthmatic subjects inhaled a control NaCl aerosol and the following sulfates: ammonium sulfate, sodium bisulfate, ammonium bisulfate, and sulfuric acid. A Lovelace generator produced particles with an average MMAD of approx. 1.0 ..mu..m (sigma/sub g/ approx. = 2.0) and concentrations of 0.1 and 1.0 mg/m/sup 3/. By double-blind randomization, all subjects breathed these aerosols for a 16-minute period. To determine if sulfate inhalation caused increased reactivity to a known bronchoconstrictor, all subjects inhaled carbachol following each 16-minute exposure. Before, during, and after exposure, pulmonary function studies were performed. When compared to NaCl, sulfate (1 mg/m/sup 3/) produced significant reductions in airway conductance and flow rates in asthmatics. The two most sensitive asthmatics demonstrated changes even at 0.1 mg/m/sup 3/ sulfate. To a far more significant degree, the bronchoconstrictor action of carbachol was potentiated by sulfates more or less in relation to their acidity in normals and asthmatics.

Analysis of predisposition of bronchial asthma by means of canonical analysis

The purpose of this paper is to clarify the relationship between bronchial asthma and various factors.Using 677 cases of the control children (Group C) made identical in the age composition, school and class with 677 cases (448 boys; 229 girls) of the asthmatic children (Group A) obtained by a fact finding survey carried out in March 1970 on bronchial asthma among all kindergarten children, elementary and junior high school children in Takatsuki City, we made a canonical analysis by sex on 26 factors such as various diseases and past histories of the children and their families with “Yes” as 1 and “No” as 0, the result of which are as follows.1) It was found that factors closely related to bronchial asthma are the past history of the children concerned such as, catching cold easily, allergic rhinitis and eczema and the family history of asthma both in boys and girls, and that urticaria, likewise alleged to be a major allergy, plays a small role in bronchial asthma.2) A canonical analysis made on the major factors, namely, the past histories of asthma (parents, grandparents), eczema (children themselves, parents, grandparents), allergic rhinitis (children themselves, parents, grandparents), catching cold easily (children themselves) and pneumonia (children themselves) in Group A and Group C also revealed a considerable difference between the astmatic group and the control group in the correlation ratio, 0.579 for boys and 0.562 for girls.3) Judging from the distribution of incidence by substituting the values of 588 boys and 355 girls who have the history of asthma and who have had no asthmatic attack for the past two years (Group B) into Y=C'X showed that they were located midway between the asthmatic group and the control group or slightly closer to the asthmatic group both in boys and girls.4) Meanwhile, the canonical analysis made on three groups A, B and C also gave almost the same results as with two groups both in boys and girls.Above the findings showed that one can learn the degree of predisposition and presume the onset and prognosis of bronchial asthma by means of such an analysis.

The importance of mites in house dust sensitivity in Barbadian asthmatics.

SummaryHouse dust sensitivity is a common precipitating cause of naso‐respiratory allergy in Barbados. A high degree of correlation between skin tests to house dust and to mite extracts was found. The pyroglyphid species Dermatophagoides pteronyssinus occurred in high densities in samples of mattress and bedroom dust. Twenty‐two other species of mites were identified in the dust samples and in certain cases some of these species were more abundant than D. pter. Skin tests were positive in a high proportion of dust sensitive asthmatics tested with extracts prepared from five species of mite in addition to D. pter. and D. farinae. There appears to be a relationship between the density of D. pter. in mattress dust and allergy to house dust.

Local effects of beta-adrenergic blocking drugs in histamin sensitive asthmatics

In 100 asthmatic patients the effects of several beta adrenergic blocking drugs were compared after inhalation. — Propranolol, pronethalol and DU 21445 showed a definite decrease of the one-second Forced Expiratory Volume. Ciba 39'089-Ba, H 56/28 and ICI 50,172 induced only a slight effect. — It was shown that dextro-isomers of beta blocking drugs have no influence on airway resistance, and that the laevo-isomers are responsible for the increase of airway resistance in asthmatics. The mechanism of effect is discussed.