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Biomedical subjects

J C Henderson

Publications and source records attributed to J C Henderson.

6 recordsLinked to original sources
PubMed1996

A comparison of the effects of an alpha-agonist, an anti-muscarinic agent and placebo on intranasal histamine challenge in allergic rhinitis.

Autonomic receptors play a part in the physiology and pathology of the nasal mucosa. The effect of an alpha-agonist and an anti-muscarinic agent on histamine-challenge was examined on patients with perennial allergic rhinitis. Nine patients received saline, oxitropium bromide 0.075%, or xylometazoline hydrochloride 0.1% in a double-blind fashion. Sequential challenge with increasing doses of histamine were given and resistance changes, sneezes and volume and content of secretion measured. Histamine challenge produced dose-related increases in nasal resistance (P < 0.0001), lavage fluid volume (P < 0.01) and total protein (P < 0.01). Following xylometazoline, histamine produced little increase in resistance compared with saline and oxitropium bromide (P < 0.0001). The latter reduced the dose-related increase in resistance (P < 0.01) and nasal lavage fluid volume (P = 0.0007) and total protein (P = 0.023) seen with saline. These results confirm the importance of alpha-adrenergic and muscarinic receptors in the human nasal mucosa and suggest mechanisms of action for these drugs in perennial allergic rhinitis.

Adrenergic alpha-Agonists↗
PubMed1995

The effect of topical fluticasone propionate on intranasal histamine challenge in subjects with perennial allergic rhinitis.

The mechanism of action of topical intranasal steroids is obscure. To investigate this, we have studied the effects of a topical intranasal corticosteroid, fluticasone propionate on nasal airflow resistance (Rnaw), secretions, cytological smears and symptoms. Fluticasone propionate aqueous nasal spray was given to 11 patients with perennial allergic rhinitis in a double-blind, placebo-controlled study. On each day, patients were challenged with ascending doses of histamine. Rnaw, secretion volume, total protein, mucin, lysozyme and albumin were measured. Nasal smears were taken and sneezes counted. Diary card data were collected for both treatment periods. There was a significant, dose-related increase in Rnaw and sneezing on histamine challenge. A single dose of fluticasone had no effect on any parameter. After 4 weeks of treatment, resistance measurements were reduced (post-challenge g.m.2.8 cmH2O/l/s, Q1-Q3 1.6-4.8; placebo 4.2, 2.9-5.3: P < 0.0001) as were baseline secretion volumes (mean 2.4 ml/5 min, c.i.1.9-3.0; placebo 3.3, 2.8-3.8: P < 0.05). Eosinophil counts were suppressed (fluticasone 5.8%, c.i. 4.0-15.7; placebo 23.3%, 12.4-34.1: P < 0.05) and the composite symptom score reduced (P < 0.05). Fluticasone has long-term effects on the nasal response to histamine in perennial allergic rhinitis and part of this effect is likely to be vascular.

Administration, Topical↗
PubMed1994

The effect of topical sodium cromoglycate on intranasal histamine challenge in allergic rhinitis.

Topical sodium cromoglycate is used to treat allergic diseases of the upper and lower airways. To investigate its mechanisms of action, intranasal histamine challenge was used in nine subjects with perennial allergic rhinitis. After a preliminary day where subjects' reactivity thresholds (D100) for histamine were determined, intranasal sodium cromoglycate was administered in a double-blind, placebo-controlled fashion. Graded (D100/3, D100, D100X3), sequential challenges were performed on days 1 and 21 of each course, and responses measured by changes in nasal airway resistance, sneezes, secretion volume and secretion content: total protein, lysozyme and mucin. After a single dose of sodium cromoglycate, there was no change in resistance, but secretion volumes fell significantly (3.12 ml/5 min c.i. 2.83-3.4; placebo 3.61, c.i. 3.32-3.90: P = 0.026). After a 3-week-course, there was a significant fall in resistance (4.29 cm H2O/l/s, c.i. 3.85-4.72; placebo 5.45, c.i. 5.01-5.88: P < 0.0001). No change in other parameters was observed. Thus, in perennial allergic rhinitis, intranasal sodium cromoglycate has both short- and long-term effects on nasal reactivity to histamine challenge. Acutely, there is a reduction in nasal lavage fluid volume which may be the result of reduced irritant receptor activity. After a 3-week course, there is a reduction in nasal resistance responses, a possible anti-inflammatory effect.

Administration, Intranasal↗
PubMed1993

Decrease of histamine induced bronchoconstriction by caffeine in mild asthma.

BACKGROUND: While high doses of caffeine may affect pulmonary function and bronchial challenge tests in patients with mild asthma, the effects of lower doses (< or = 5 mg/kg) are less well documented. Specific recommendations exist for withholding theophylline, but not caffeine, before bronchoprovocation and pulmonary function testing. METHODS: To assess the effect of a single oral dose of caffeine (5 mg/kg) on FEV1 and bronchial responsiveness to histamine a double blind, placebo controlled study was performed in eight patients with mild stable asthma. RESULTS: While caffeine had no effect on FEV1, mean (95% confidence interval) log PC20 histamine was significantly higher 150 minutes [caffeine = 0.99 (0.2) mg/ml, placebo = 0.53 (0.29)] and 240 minutes [caffeine = 0.89 (0.24), placebo = 0.44 (0.26)] after administration of caffeine than after placebo. CONCLUSIONS: Caffeine should be excluded from the diet for a period of more than four hours before bronchial provocation testing. The exact length of time for which it must be excluded requires further study.

Adult↗