Adenosine monophosphate is not superior to histamine for bronchial provocation test for assessment of asthma control and symptoms.

BACKGROUND: Adenosine monophosphate (AMP) may reflect airway inflammation and hyperresponsiveness, but relationship between AMP and histamine (His, a conventional stimulus) bronchial provocation test (BPT) in asthma is not fully elucidated. OBJECTIVES: To compare both BPTs and determine their utility in reflecting changes of asthmatic symptoms. METHODS: BPTs were performed in a cross-over fashion, at 2-4 day intervals. Cumulative doses eliciting 20% FEV1 fall (PD20 FEV1 ), diagnostic performance and adverse events (AEs) were compared. Patients with PD20 FEV1 lower than geometric mean were defined as responders, otherwise poor responders. Patients with uncontrolled and partly controlled asthma, who maintained their original inhaled corticosteroids therapy, underwent reassessment of airway responsiveness and asthmatic symptoms 3 and 6 months after. RESULTS: Nineteen uncontrolled, 22 partly controlled and 19 controlled asthmatic patients and 24 healthy subjects were recruited. Lower PD20 FEV1 geometric means were associated with poorer asthma control in His-BPT (0.424 µmol vs 1.684 µmol vs 3.757 µmol), but not AMP-BPT (11.810 µmol vs 7.781 µmol vs 10.220 µmol). Both BPTs yielded similar overall diagnostic performance in asthma (area under curve: 0.842 in AMP-BPT vs 0.850 in His-BPT). AEs, including wheezing and tachypnea, were similar and mild. Ten patients with uncontrolled and 10 partly controlled asthma were followed-up. At months 3 and 6, we documented an increase in PD20 FEV1 -AMP and PD20 FEV1 -His, which did not correlate with reduction asthmatic symptom scores. This overall applied in responders and poor responders of AMP-BPT and His-BPT. CONCLUSION: Despite higher screening capacity of well-controlled asthma, AMP-BPT confers similar diagnostic performance and safety with His-BPT. AMP-BPT might not preferentially reflect changes asthmatic symptoms.

Tyramine and histamine risk assessment related to consumption of dry fermented sausages by the Spanish population.

Tyramine and histamine are the main dietary bioactive amines related to acute adverse health effects. Dry fermented sausages can easily accumulate high levels of these hazards and are frequently consumed in Spain. The present work aims to assess the exposure to tyramine and histamine from the consumption of dry fermented sausages by the Spanish population and to assess the risk to suffer acute health effects from this exposure. A probabilistic estimation of the exposure to these hazards was derived combining probability distributions of these amines in dry fermented sausages (n = 474) and their consumption by the Spanish population. The mean dietary exposure to tyramine and histamine was 6.2 and 1.39 mg/meal, respectively. The risk of suffering hypertensive crisis or histamine intoxication by healthy population due to tyramine or histamine intake, respectively, exclusively from dry fermented sausages, can be considered negligible. For individuals under treatment with MAOI drugs, the probability to surpass the safe threshold dose (6 mg/meal) was estimated as 34%. For patients with histamine intolerance, even the presence of this amine in food is not tolerable and it could be estimated that 7000 individuals per million could be at risk to suffer the related symptoms after consuming dry fermented sausages.

Correlation between subjective and objective assessment of nasal hyperreactivity.

The aim of this study was to investigate if there is a correlation between symptom score and response to histamine challenge in patients suffering from non-allergic nasal hyperreactivity. Eighteen patients with perennial rhinitis entered the trial. All had negative skin prick tests and normal total IgE. The nasal mucosa was challenged with three histamine concentration levels, 1, 2 and 4 mg/ml. The objective response was recorded with rhinostereometry and was compared to symptom scores estimated by the patients on a visual analogue scale. With simple analysis of regression there was a significant correlation when challenging with 2 mg/ml (R = 0.695, p < 0.01) and 4 mg/ml (R = 0.569, p < 0.05). The results indicate that the model could be useful for objective assessment of the degree of non-allergic nasal hyperreactivity.

Assessment of the wheal size and skin blood flow of the erythema induced by histamine and its modification with cetirizine and ebastine: a crossover, double-blind study.

In order to assess the antihistaminic power of cetirizine and ebastine, we designed a randomized, double-blind, crossover study, measuring their capacity to modify skin blood flow induced by a histamine prick test. The vasomotor response was compared using a laser Doppler flowmeter. Two hours after intake of the antihistaminic drug, there were significant differences between both drugs: at 4 h, the antihistaminic effect of cetirizine persists, whereas ebastine only showed moderate activity. The reduction of the cutaneous blood flow values (CBFV) showed good activity in both groups, but cetirizine was more potent and showed faster activity than ebastine.