Arend Bouhuys

Inhibition of histamine-induced airway constriction by ascorbic acid.

Abstract We studied the effect of ascorbic acid on histamine-induced airway constriction in 17 healthy subjects; we also investigated its effect on guinea pig tracheal strips in vitro . Ventilatory function was measured by recording partial expiratory flow-volume (PEFV) curves on which maximum flow rates at 50 per cent VC and at 25 per cent VC were calculated. Following oral administration of 500 mg. ascorbic acid, the mean reductions of V max at 50 per cent VC and V max at 25 per cent VC after histamine inhalation were significantly smaller in comparison with placebo administration (P in vitro relaxations of tracheal strips by ascorbic acid were reduced by 2.5 μg propranolol. Ascorbic acid probably has a direct effect on airway smooth muscle; in the guinea pig trachea its effect may be mediated by γ-adrenergic receptors.

Airway responses to histamine, acetylcholine, and propranolol in anaphylactic hypersensitivity in guinea pigs☆☆☆

Abstract Using changes in tidal volume and dynamic lung compliance, airway responses to histamine, acetylcholine, and propranolol were investigated in different groups of guinea pigs before and after active or passive sensitization. The threshold doses to inhaled histamine, acetylcholine, and propranolol were identical before and after sensitization. Similarly, the slope of dose response curves to these drugs and the time course of recovery from airway constriction were comparable in control and sensitized animals. The slopes of dose response curves to histamine and acetylcholine were parallel. Threshold doses to acetylcholine (T ACH ) and histamine (T H ) were proportional. The average ratio TACHTH was 7.7. There was no correlation between threshold doses and slopes of dose response curves for propranolol and those for histamine or acetylcholine. Antigen challenge resulted in decreases of dynamic lung compliance and in increases of airway resistance and frequency, which were maximal 60 to 130 seconds after challenge. When functional parameters after antigen challenge had returned to normal, bronchial responses to histamine, acetylcholine, and propranolol were exaggerated. These exaggerated responses were reproducible, transient, variable from animal to animal, and related to the antigen dose. Guinea pig anaphylaxis does not lead to the prolonged hypersensitivity to chemical mediators, which characterizes human reaginic asthma, but to a temporary enhancement of responses to acetylcholine, histamine, and propranolol.

Epidemiology of chronic lung disease in a cotton mill community.

We recorded respiratory symptoms and maximum expiratory flow-volume curves in 645 white male and female cotton textile workers, aged 45 years and older, with an average of 35 years employment in carding, spinning, yarn preparing, weaving and other jobs in cotton textile mills. We included retired as well as active workers, to avoid the biases inherent in studies of active workers only. We compared the data on the textile workers with those of 662 female and 498 male white residents of three communities without cotton textile mills (controls), considering sex, age and smoking habits. Textile workers of both sexes, irrespective of age, had significant excesses of chronic cough, wheezing, dyspnea and other symptoms, in comparison with the controls. Work in textile mills was the prime variable affecting symptom prevalence, with smoking as an additional significant variable for all symptoms except dyspnea. The lungfunction data confirmed that textile workers were at much greater risk of chronic lung disease, with loss of function, than the controls, in all smoking categories. There was evidence that chronic lung disease often led to premature retirement among the male textile workers. The excess risk of lung-function loss occurred among workers in yarn preparing and weaving, as well as in carding and spinning, but not among workers employed in clothrooms and in other dust-free jobs. At least 35,000 men and women in the U.S. may suffer from disabling lung-function loss, owing to chronic lung disease, as a result of their work in cotton textile mills. Adequate programs of prevention and control of chronic lung disease, a late stage of byssinosis, as well as of the earlier acute manifestations of byssinosis, are urgently needed.

Tachyphylaxis to β-adrenoceptor agonists in guinea pig airway smooth muscle in vivo and in vitro

Abstract β-Adrenoceptor tachyphylaxis was induced by incubating spirally cut guinea pig tracheas with isoproterenol (2.4 × 10 −7 M) for 20 min. This incubation reduced the relaxant effects of catecholamines but not of dibutyryl cyclic AMP, theophylline or sodium nitrite. Tracheas incubated with norepinephrine, phosphodiesterase inhibitors or cyclic nucleotides became tachyphylactic to isoproterenol. Pretreatment with indomethacin prevented induction of tachyphylaxis. Incubation with adenosine, methoxamine or sodium nitrite did not induced β-adrenoceptor tachyphylaxis. When we gave isoprpterenol intramuscularly to guinea pigs, airway sensitivity to aerosolized histamine was unchanged but the toxicity of parenterally administered histamine was increased. A prolonged treatment with isoproterenol reduced airway sensitivity to histamine aerosols; this reduced sensitivity was reversed by indomethacin. Thus, β-adrenoceptor tachyphylaxis may not explain increased toxicity of parenteral histamine after isoproterenol treatment. Elevated levels of cyclic AMP and an increased synthesis of prostaglandins may result in diminished response to β-receptor stimulation.

PRESSURE‐FLOW EVENTS DURING SINGING

The singer must coordinate the movements of the vocal cords and the vocal tract (which determine pitch, loudness, and quality of the tones) with the movements of the respiratory bellows (which produce the pressure and flow of air needed to drive the larynx). During phonation, both subglottic pressure and the flow rate of air through the larynx must remain constant if one wants to produce a tone of constant pitch and loudness. During singing of a song, on the other hand, these pressures and flow rates are subject to changes related to the requirements of the individual tones. We will briefly discuss breathing patterns during singing of songs, but will concentrate on the pressure and flow events during production of single constant tones, when a “steady state” of pressure and flow rate prevails. The mechanical analy3is of these events will be summarized only; its details have been reported elsewhere, as have the technical details of the methods used (Bouhuys et al., 1966).

Importance of the indoor environment in air pollution exposure.

A portable personal air pollution sampler was used to measure the exposure of twenty children to respirable particulates, sulfur dioxide, and nitrogen dioxide over a 24-hour period. Particulate exposures were significantly higher among children who lived with one or more smokers, and exceeded the primary air quality standard in nineteen of the twenty subjects. To a large extent, an individuals respirable particulate load appears to be determined by exposure to indoor rather than outdoor pollutants.

Acute airway responses to hair-spray preparations.

Abstract Acute exposures (20 seconds) to hair-spray preparations A, B and C caused significant decreases of maximum expiratory flow rates at low lung volumes in healthy men and women. Peak expiratory flow rates were reduced slightly after hair spray A only. The decreases were more pronounced on partial than on maximal expiratory flow-volume curves. On the partial curves, flow at mid-vital capacity decreased on the average 22 per cent immediately after exposure to spray A (16 subjects), 21 per cent after spray B (16 subjects), 29 per cent after spray C (nine subjects) and 4 per cent after placebo spray. These changes suggest that hair sprays cause acute, reversible narrowing of small airways. The chemical nature of the active ingredient (or ingredients) in hair sprays is not known; their mode of action may involve histamine release from lung tissue or a direct effect on airway smooth muscle, or both. Controlled inhalation studies in man should be required as part of the toxicologic evaluation of consumer p...

Physiology and Musical Instruments

This talk on human factors in the performance of wind instruments was presented at the annual meeting of the Acoustical Society of America, Cleveland, Ohio, held on November 19–21, 1968.

Airflow Control by Auditory Feedback: Respiratory Mechanics and Wind Instruments

The auditory signal provided by a soprano recorder in a breathing circuit can help human subjects to regulate inspiratory and expiratory airflow rates at constant preset levels. This method of airflow control is useful in studies of the static and dynanic mechanical properties of the lungs and may have additional applications in human respiration physiology.

Byssinosis: Scheduled asthma in the textile industry

Byssinosis, an occupational lung disease of textile workers, can be distinguished from asthma and other forms of reversible airway obstruction by its characteristic history of chest tightness, cough, and wheezing on first working days after absence from work. Lung function tests before and after exposure to dust on first working days confirm the occurrence of airway obstruction as an acute effect of dust exposure during work in carding, spinning and other dusty operations in cotton, flax and soft-hemp factories. The dust in these factories contains a water-soluble, heat-stable agent which releases histamine from human lung tissue. In the case of cotton dust, this agent originates in the bracts of the cotton plant. Recent epidemiological studies in U.S. cotton textile workers and in Spanish hemp workers have shown that prolonged exposure to textile dusts often leads to disabling chronic lung disease and to loss of lung function which is irreversible with β-adrenergic drugs. At this stage, the disease may progress even after exposure to dust ceases. This recent work further strengthens the need for adequate control of exposure to respirable dust among textile workers. Implementation of this goal remains elusive because of its economic consequences, in spite of adequate medical documentation of the health risks of textile dust exposure during the past 20 years.Byssinosis, an occupational lung disease of textile workers, can be distinguished from asthma and other forms of reversible airway obstruction by its characteristic history of chest tightness, cough, and wheezing on first working days after absence from work. Lung function tests before and after exposure to dust on first working days confirm the occurrence of airway obstruction as an acute effect of dust exposure during work in carding, spinning and other dusty operations in cotton, flax and soft-hemp factories. The dust in these factories contains a water-soluble, heat-stable agent which releases histamine from human lung tissue. In the case of cotton dust, this agent originates in the bracts of the cotton plant. Recent epidemiological studies in U.S. cotton textile workers and in Spanish hemp workers have shown that prolonged exposure to textile dusts often leads to disabling chronic lung disease and to loss of lung function which is irreversible with β-adrenergic drugs. At this stage, the disease may progress even after exposure to dust ceases. This recent work further strengthens the need for adequate control of exposure to respirable dust among textile workers. Implementation of this goal remains elusive because of its economic consequences, in spite of adequate medical documentation of the health risks of textile dust exposure during the past 20 years.