Biomedical subjects

R J Mezey

Publications and source records attributed to R J Mezey.

3 recordsLinked to original sources

PubMed1979

Antigen-induced bronchospasm in conscious sheep.

In 10 conscious ewes with cutaneous sensitivity to Ascaris suum, measurements of pulmonary resistance (RL), static lung compliance (Cst), functional residual capacity (FRC), and arterial blood gas composition along with arterial plasma histamine concentration (H) were obtained before and after inhalation challenge with A. suum extract. Five animals showed no changes in respiratory mechanics after A. suum challenge; in these H did not change. The remaining five animals responded to A. suum challenge with bronchospasm reflected by the following maximum changes in mean values that were significant 15 and 30 min after beginning of challenge, respectively: RL 248% , FRC 126%, specific pulmonary conductance 33%, and arterial PO2 63% of base line. These parameters returned towards base line by 120 min. No changes occurred in Cst, arterial PCO2, and pH. Five minutes after beginning of A. suum challenge, mean H was increased to 423% of base line with a return to base line 10 min later. In the same 5 animals, no changes were observed in pulmonary function or H after inhalation of ragweed extract (control). These results suggest that antigen-induced bronchospasm in sensitized conscious sheep represents an anaphylactic airway response and shares distinct physiological features with human bronchial asthma including pulmonary hyperinflation.

Airway Resistance↗

PubMed1978

Mucociliary transport in allergic patients with antigen-induced bronchospasm.

Tracheal mucous velocity (TMV) and respiratory mechanics were measured in asymptomatic asthmatic patients with ragweed hypersensitivity before and after inhalation of specific antigen, and with or without cromolyn sodium pretreatment. TMV was measured radiographically, and the airway response to bronchial provocation was monitored by measurements of forced expiratory volume in one sec and specific airway conductance. TMV was significantly less (6.3 +/- 2.3 mm per min, mean +/- SD) in the 6 asymptomatic asthmatic patients than in 7 normal subjects (11.6 +/- 3.6 mm per min, mean +/- SD). In the asthmatic patients, mean TMV diminished to 72 per cent of baseline immediately after bronchial provocation when specific airway conductance was decreased to 65 per cent of baseline or less, with a further decrease in TMV to 47 per cent of baseline after one hour, at which time respiratory mechanics had returned to baseline values. Pretreatment with cromolyn sodium prevented the decrease in TMV after bronchial provocation. We concluded that in asymptomatic patients with allergic asthma, (1) baseline TMV is impaired, (2) inhalation of specific antigen causes a marked decrease in TMV independent of the degree of bronchospasm, and (3) the decrease in TMV may be related to the release of chemical mediators.

Adolescent↗

PubMedDate not supplied

Peripheral airway function in antigen-induced bronchoconstriction.

The density dependence of the maximum expiratory flow-volume curve, functional residual capacity (FRC) and specific airway conductance (SGaw) were studied in 16 asymptomatic subjects with ragweed hypersensitivity and a history of bronchial asthma, before and during bronchial provocation with ragweed extract (dose-response curve), and following inhalation of isoetharine. In ten of these subjects (seven "reactors" and three "non-reactors"), the baseline volume of isoflow (VisoV) was found to be greater than 20% of forced vital capacity. During antigen challenge, VisoV increased in all subjects; ten of these showed a greater than 35% decrease in SGaw (mean 45%) while the remaining six showed a decrease in SGaw of less than 20% (mean 9%), suggesting central and peripheral airway constriction in the former ("reactors") and primarily peripheral airway constriction in the latter ("non-reactors"). The beta-adrenergic agonist isoetharine increased SGaw and decreased VisoV, suggesting dilation of both central and peripheral airways. We conclude that in asymptomatic subjects with asthma and ragweed hypersensitivity a) peripheral airway dysfunction is frequently present, b) during antigen challenge VisoV may be a more sensitive indicator of airway response than SGaw, and c) the beta-adrenergic agonist isoetharine exhibits its bronchodilator effect in both central and peripheral airways following antigen challenge.

Adult↗