Effects of ackee fruit extracts on bronchomotor tone in rats

The unripe ackee fruit, when eaten, is known to cause serious clinical manifestations, including vomiting, hypoglycaemia and acidosis. The effects, of various extracts from the arilli of the unripe fruit (including hypoglyin-A) on the lungs from rats were examined in an in vitro preparation. All the extracts were found to induce moderately severe broncho-constriction, indicating a possible contribution of these effects to the observed toxicity of ackee (AU)

Comparative observations of mucus transport velocity in health and disease

The present study evaluated mucus transport velocity (MTV) in different areas of the tracheobronchial tree in vitro in normal, acute and chronic bronchitic animals. The average MTV in animals ranged from 11.5 mm/min in the trachea to 0.64 mm/min in the pre-terminal bronchus. Chronic bronchitic animals showed mucus hypersecretion, areas of ciliary abnormality and mucus stagnation. The mean transport velocities ranged from 21.2 mm/min in the trachea to 4.1 mm/min in the pre-terminal bronchus. In the acutely ill animals, MTV ranged from 2.5 mm/min in the trachea to zero below the upper lobar bronchus. It is postulated that the higher than normal values in chronic bronchitis are due to altered mucus rheology, increased peristalsis and linear acceleration; whereas those in acute bronchitis were attributed to an early phase of viral or bacterial infection. (AU)

Aspiration in seriously ill patients: a study of amylase in bronchial secretions

Bronchial secretions from 21 patients with moderate to severe chest infections were obtained by transtracheal aspiration. Six seriously ill patients showed greatly increased levels of amylase activity in the bronchial secretions compared with those found in the 15 less ill patients. This amylase was almost certainly derived from oropharyngeal contents and its presence suggests that aspiration may be more common in comatose and semi-comatose patients than is generally appreciated. (Summary)

Tracheobronchial function in health and disease: effect of mucolytic substances

The effect of mucolytic and expectorant substances on ciliary beat frequency, mucus transport velocity and mucus production, was investigated in normal and bronchitic rats. The results showed that: (i) N-acetylcysteine and S-carboxymethylcysteine were mildly cilioexcitatory at low and ciliodepressive at higher concentrations in both normal and bronchitic rats. A similar pattern was seen in mucus transport velocity. (ii) Bisolvan enhanced all aspects of muciciliary activity in both groups of animals. Sobrepin was less effective than Bisolvan and more effective than Tachoquilin. (iii) Geleomytrol, Ozothin and prostaglandin E1 were all cilioexcitatory in rats with bronchitis. Mucus transport velocity was similarly stimulated by both Geleomyrtol and Ozothin. (iv) Ammonium chloride and potassium iodide enhanced mucociliary activity in normal and bronchitic rats. (v) All substances stimulated mucus production, however, the most potent was prostaglandins E1. The mechanisms for increased mucociliary activity involve inter alia the probable cleaving of disulphide bridges, decreased mucosal swelling, altered rheological characteristics and stimulation of adenylate cyclase (AU)

Direct determination of luminal diameter changes in intrapulmonary airways

A method is decribed for the direct measurement of changes in luminal diameter at all levels of the airway. Using this method it was found that (i) abrupt bronchiolar collapse occurred in the preterminal and terminal bronchioles once the luminal diameter was reduced to a critical level: (ii) decreased temperatures resulted in airway narrowing which was reversed by increasing the temperature to above 25 degrees C; as a rule, airway narrowing followed a cranial to caudal direction, and higher concentration of a drug being required to close the peripheral airways; (iii) bronchodilators except Carbuterol had no effect on resting bronchial tone or on acetylcholine-induced constriction in the absence of O-adrenoreceptor blockade; (iv) at 35 degrees C rhythmic waves (frequency 6--20/min) were observed; these waves travelled from the periphery in a cranial direction. (AU)

Fibroxanthomatous pseudotumour of the lung

The clinical, radiological and pathological features of fibroxanthomatous pseudotumour of the lung in a 17-year-old Jamaican female Negro are described. The patient was symptom-free 4 years after treatment by conservative surgery. The condition is extremely rare. Its aetiology and pathogenesis are discussed. (Summary)

Tracheobronchomegaly

Over fifty cases of tracheobronchomegaly reported in the literature are reviewed and two new cases are described. The radiological appearances of this rare condition are described and its concomitant occurrence with bronchiectasis is noted. The condition is thought to be due to faulty development of the connective tisssues of the tracheobronchial tree. However, a study of the age of presentation showed that the majority presented in the third or later decades which suggests that it is an acquired rather than a developmental anomaly. (AU)

Water content level in inspired air on specific airway resistence in rats

The effect of increasing water content in inspired air on specific airway resistence in rats was assessed. The results show that specific airway resistances were significantly related to the water content of the inspired air, above 15.02 mg/m3, the duration of water content exposure and to the type of water nebulized. It is suggested that the increase is composed of a local and neural element caused by accumulation of mucus or mucosal swelling and changes in the composition and consistency of the mucus lining layer, respectively (AU)

Critical anatomical site in healthy subjects from observation of forced expiratory volume curves with external resistances

The internal diameter of the air passages narrows from the trachea to the periphery of the lungs. Because of this it should be possible to predict the site at which the greatest change in resistance would occur for a given flow rate using the orifice flow equation (P = p/Cý(1/A2ý 1/A1ý) Vý where p = density of air, C = discharge constant which depends on the roughness of the tube and on Reynolds number, V is the volume rate of flow and A1 and A2 are the cross sectional areas) and compare it with forced expiratory volume curves (FEV) in healthy subjects. Theoretical calculations showed that the 3rd-6th generation of the bronchial tree contributed about 40 percent to the total airway resistance. Direct measurements by previous workers showed that approximately 55 percent of the total pulmonary resistance was contributed by the 3rd-6th generation i.e. 3-6 mm internal diameter bronchi. Results of FEV curves in normal subjects against external resistance of known internal diameters will be presented. These results show that the critical orifice (i.e. the point at which greatest inflection begins in the FEV curve) is in the range of 6-9 mm internal diameter (around the 3rd generation of the tracheobronchial tree). An analog of the tracheobronchial tree is being prepared to simulate the resistance to breathing, and thereby provide a simple method of measuring airway resistance (AU)

Histogenesis of intrapulmonary and endobronchial hamartomas and chondromas (cartilage-containing tumors): a hypothesis

A study of selected examples from a series of 42 cartilage-containing tumors of the lung support the hypothesis that intrapulmonary hamartomas and chondromas and endobranchial hamartomas and chondromas are the same lesion and are neoplasms that arise in the connective tissue of the bronchial walls. The apparent differences in the appearance of these neoplasms are due to their site of origin. i.e., whether they arise in large or small bronchi, and their direction of growth, i.e., whether they grow into or away from the lumen of the bronchus of origin. They should all be referred to as cartilage containing tumors of the lung and bronchi. (Summary)

Distribution of bronchial gland measurements in a Jamaican population

Measurements of the gland thickness and Reid index have been made on bronchi obtained at necropsy on 53 male and 52 female Jamaicans. The mean values for the Reid index and mucous gland thickness obtained were 0.314 and 0.192mm. for males, and 0.302 and 0.170mm. for females respectively. No significant increase in values was seen with age, although the data suggest this trend. The results have been compared with data published from Montreal and the same overall Gaussian distribution is seen. This supports the suggestion that the gland measurements in non-bronchitic and bronchitic subjects do not fall into two distinct groups but are part of a continous distribution. The similarity of the two studies is also of interest as the populations are drawn from two distinct environments, one from a non-industrialized tropical island, the other from a large city in the northern hemisphere.(AU)