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T Higenbottam

Publications and source records attributed to T Higenbottam.

At least 127 records · Page 7Linked to original sources
PubMed1987

The mechanism of aerosol-induced bronchoconstriction.

To gain insight into the mechanism of aerosol induced bronchoconstriction the differences between ultrasonically-nebulized aqueous-induced bronchoconstriction and cough are contrasted. Both normal subjects and asthmatics cough in response to inhalation of aerosol low in chloride ions (Cl-). This is putatively a result of stimulation of rapidly-adapting receptors (RARs). Normals do not develop bronchoconstriction as a result of inhalation of aqueous aerosols. Asthmatics however do but only when the tonicity is increased above or below normal; (Cl-) is not important. Inhaled lignocaine inhibits cough but not bronchoconstriction whilst sodium cromoglycate (SCG) inhibits bronchoconstriction but not cough. As SCG may inhibit vagal C-fibre receptors it is possible that different vagal afferent receptors are involved in cough and bronchoconstriction. Small but significant bronchodilatation in normals attenuates aerosol-induced cough which can be explained by central modulation of medullary cough neurones by slowly-adapting receptors (SARs). As the same occurs with reflex bronchoconstriction, a complex organisation of vagal afferents can be suggested, where different receptors are responsible for cough and bronchoconstriction and SAR activity modulates the medullary neurones which initiate the two reflexes.

Aerosols↗
PubMed1985

Pulmonary epithelial permeability after inhaling saline, distilled water "fog" and cold air.

It is recognized that hyperventilation of cold air and the inhalation of fine mists of distilled water provoke significant bronchoconstriction in the asthmatic individual, yet little is known as to how these provocations affect the structural integrity of the alveolar epithelial membrane. In 11 normal subjects, the following effects have been studied: cold air hyperventilation for three minutes, inhalation of 80 L of ultrasonically nebulized distilled water "fog," and 80 L of isotonic saline "fog" on the half time clearance (T1/2) from the alveoli of technetium 99m diethylene triamine penta acetate (DTPA), inhaled as an aerosol. The DTPA T1/2 provided a measurement of pulmonary epithelial permeability.

Aerosols↗
PubMed1985

Tobacco smoking and the pulmonary surfactant system.

To explain enhanced retention of water insoluble gases and water insoluble particulate matter (tar)when smoke is inhaled we propose that these compounds interact physically with phospholipids forming the mono-molecular layer of surfactant lining the alveolar epithelium. This would account for the alteration in surface tension lowering properties of surfactant when exposed to whole smoke but not gas phase. Also it explains the observed reversible reduction in 'free' surfactant as opposed to cellular contained surfactant in smokers. Surfactant levels improve rapidly on abstinence from smoking and the time course of this improvement follows closely the reduction in alveolar epithelial permeability to a small hydrophilic molecule of diethylene triamine penta acetate (DTPA) and the improvement in homogeneity of ventilation as measured by the slope of alveolar washout (a measure of elusta properties of the peripheral airspaces of the lungs).

Animals↗
PubMed1983

Carbon monoxide yield of cigarettes and its relation to cardiorespiratory disease.

Estimates of the carbon monoxide yield of their cigarettes have been obtained for 4910 smokers (68% of all smokers) in the Whitehall study of men aged 40 to 64. In the 10 years after examination 635 men died. When men smoking cigarettes with high carbon monoxide yield were compared with those smoking cigarettes with a low yield, and after adjusting for age, employment grade, amount smoked, and tar yield, the risk of death was 32% lower for coronary heart disease, 49% higher for lung cancer, and 10% lower for total mortality; these differences were not statistically significant. Among men who said that they inhaled the risk of fatal coronary heart disease was 51% lower in the high carbon monoxide group (p less than 0.01), while the risk of lung cancer was 75% higher. These results provide no evidence that a smoker can reduce his risk of death by smoking a brand with a low carbon monoxide yield; he might even increase it. The complex interactions between characteristics of the smoker, smoking behaviour, constituents of tobacco smoke, and health are again demonstrated.

Adult↗
PubMed1983

Bronchial reactivity in asthmatic adults with normal spirometric values.

A comparison was made between airways obstruction produced by exercise. Hyperventilation of cold air, hyperventilation of room air, and inhalation of ultrasonically nebulised distilled water. Seven asthmatics with no airflow obstruction were studied together with seven normal controls. All four provocations produced comparable mean reductions in forced expired volume in one second in the asthmatic patients, but no reduction was obtained in the controls. Whereas exercise, hyperventilation of cold air, and hyperventilation of room air were associated with heat loss from airways, inhalation of nebulised distilled water was not. Inhalation of ultrasonically nebulised distilled water offers a simple additional diagnostic test for asthma. Changes in the osmolality of airway surface liquid may possibly be the common mechanism by which "fog" and hyperventilation produce bronchoconstruction.

Adult↗
PubMed1982

Nicotine concentrations in urine and saliva of smokers and non-smokers.

Nicotine concentrations were measured in saliva and urine samples collected from 82 smokers and 56 non-smokers after a morning at work. Each subject answered a series of questions related to their recent intentional or passive exposure to tobacco smoke. All non-smokers had measurable amounts of nicotine in both saliva and urine. Those non-smokers who reported recent exposure to tobacco smoke had significantly higher nicotine concentrations (p less than 0.001) than those who had not been exposed; their concentrations overlapped those of smokers who had smoked up to three cigarettes before sampling had the greatest influence on nicotine concentrations (r=0.62 for saliva and r=0.51 for urine). Neither the nicotine for yield of cigarettes nor the self-reported degree of inhalation had any significant effect on nicotine concentrations.

Dose-Response Relationship, Drug↗
PubMed1982

Cigarettes, lung cancer, and coronary heart disease: the effects of inhalation and tar yield.

Ten-year mortality rates for lung cancer and coronary heart disease have been related to cigarette smoking habits in 17 475 male civil servants aged 40-64 and in sample of 8089 male British residents aged 35-69. Both diseases were more frequent in smokers. Lung cancer rates were higher overall for "non-inhalers", particularly in heavy smokers. Tar yield correlated with the risk of lung cancer in non-inhalers but less so in inhalers. Conversely, coronary deaths were more common among inhalers, and the effect of tar/nicotine yield (such as it was) was confined to inhalers. It appears that there are subtle interactions between the amount smoked, the tar/nicotine yield of the cigarette, and the style of smoking. Thus the effects of a change in cigarette characteristics are hard to predict, and they may be different for respiratory and cardiovascular disease.

Adult↗
PubMed1982

Plasma concentrations of lignocaine during fibreoptic bronchoscopy.

Peak plasma concentrations of lignocaine were recorded in 41 patients receiving topically applied lignocaine for fiberoptic bronchoscopy. Adequate anaesthesia was achieved in all patients with an average dose per unit weight of 9.3 +/- 0.5 mg/kg (SEM) giving a mean peak plasma concentration of 2.9 +/- 0.5 mg/l-1 (SEM) (+/- SEM 0.5). The plasma concentration exceeded toxic levels of 5.0 mg/l-1 in only two patients, and no complications were observed. Peak concentrations were influenced only by dose per unit weight administered and not by factors considered likely to influence mucosal absorption from the bronchial tree, such as sputum production, airflow obstruction, or cigarette smoking. A major proportion of the total dose of lignocaine was required to anaesthetise the nose, pharynx, and larynx, only a small proportion being needed for the bronchial tree. Lignocaine gel (2% w/v) was preferred by patients, and in a study of 10 volunteers, produced lower plasma concentrations when used as a topical anaesthetic than did lignocaine aerosol (10% w/v) or lignocaine solution (4% w/v).

Administration, Topical↗
PubMed1982

Glottis narrowing in lung disease.

We measured the separation of the vocal folds, the glottis chink, on inspiration and expiration during quiet breathing in 34 patients with varying degrees of airflow obstruction as measured by forced expired volume in one second, Width of the glottis chink was calculated from photographs of the vocal folds taken via a fiberoptic bronchoscope. To adjust the differences in photographic image size caused by variations in instrument position, we predicted the internal anteroposterior (A.P) diameter of the glottis in each patient. This was made possible by the observed high correlation (r = 0.79) between A.P diameter of the glottis and height demonstrated in a separate study in 49 adult cadavers. In patients with airflow obstruction, the glottis chink was narrowed during quiet breathing, particularly on expiration. Such differences in glottis width between patients could not be attributed to frequency of breathing or tidal volume. Indeed, during high frequency breathing (panting) at 1 to 3 Hz studied in 18 patients, further glottis narrowing was commonly observed in those with airflow obstruction. Furthermore, when 13 patients performed a maximal exhalation, in those with airflow obstruction, the glottis remained narrowed, whereas in patients with FEV1 greater than 80% predicted, the glottis opened to an inspiratory width.l These observations suggest that narrowing of the glottis potentially plays an important part in controlling airflow in patients with airway obstruction.

Adult↗