Randomised double-blind placebo-controlled study of the effect of inhibition of nitric oxide synthesis in bradykinin-induced asthma

What Was Tested

The paper reports a study of Bradykinin, published as a randomized controlled trial.

Inhaled NO is known to cause bronchodilatation in asthmatic patients.

To find out the role of endogenous NO in airway response to bradykinin in asthma, the researchers examined the effect of the NO synthase inhibitor NG-monomethyl-L-arginine (L-NMMA) on broncho-constriction after bradykinin challenge in ten patients with mild asthma.

Who Took Part

PubMed indexes the participants as adults and middle-aged adults, both men and women.

After baseline measurements of forced expiratory volume in 1 s (FEV1) participants inhaled an aerosol of L-NMMA or saline (placebo).

The researchers also assessed the effect of the inactive enantiomer of L-NMMA, D-NMMA, and placebo on bronchoconstriction after bradykinin or methacholine challenge in six of the participants.

How the Study Was Run

In design terms this was a randomized, double-blind, placebo-controlled and crossover study.

Because people in this Bradykinin study were split into groups at random, differences between the groups are less likely to reflect who happened to join each one.

Neither the participants nor the staff measuring them knew who was on Bradykinin, so expectations could not easily colour the readings.

A placebo (an inactive look-alike) gave the Bradykinin group a baseline to be compared against.

In the crossover set-up each of the participants took both Bradykinin and the comparison in turn, acting as their own control.

The study had a randomised, double-blind, placebo-controlled, cross-over design.

What Was Measured

Topics PubMed links to this paper include Aerosols, Arginine, Asthma, Bradykinin, Bronchial Provocation Tests, Enzyme Inhibitors and Lung Volume Measurements.

What This Means in Plain Language

The paper is a randomized, double-blind and placebo-controlled study of Bradykinin.

The abstract goes on to report its results in about 4 sentences; this page does not restate them, so read the paper for the findings and their limits.

The publication is from 1996 (Lancet (London, England)), a journal based in England.

More context: the Bradykinin compound page, all human trials.