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Biomedical subjects

T W Higenbottam

Publications and source records attributed to T W Higenbottam.

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

Has the management of asthma improved?

Asthma morbidity and mortality are reported to be rising in the UK, despite increased sales of anti-asthmatic drugs. To determine whether recent advances in therapy have been beneficial the results of the 1970-71 and 1981-82 national morbidity surveys in general practice and the Department of Health and Social Security surveys of prescribing for 1968 to 1985 have been examined. Between 1970-71 and 1981-82 the number of asthmatics diagnosed rose by 75%, but, for the average asthmatic, consultation, home visit, and outpatients referral rates fell significantly by 19%, 44%, and 32%, respectively. Over the same period total prescribing for airflow obstruction rose by 76%. The proportion of treatment aimed at attack prevention increased from 10.6% to 19.4%. Thus for the average asthmatic management has improved because fewer consultations are required. Increased use of inhaled topical steroids and sodium cromoglycate is probably responsible for this improvement. Nevertheless preventive treatment remains under-prescribed and asthma is still underdiagnosed.

Asthma↗
PubMed1987

The rapid reversibility of effects of changing lung volume on the clearance rate of inhaled 99Tcm-DTPA in man.

Five normal non-smoking subjects inhaled an aerosol of 99Tcm-DTPA in saline with a mass median aerodynamic diameter of 0.6 micron. The rate of clearance (k) of the inhaled 99Tcm-DTPA from lung to blood was measured using a gamma scintillation camera with computer data acquisition. During a single clearance study the subjects voluntarily breathed close to total lung capacity (TLC) and close to residual volume (RV). They breathed at one volume for 5 min, then at the opposite volume for 5 min and finally reverted to the original volume for 5 min with a 1 min pause between each manoeuvre. The order in which each subject performed these breathing patterns was randomized. Tidal volume, respiratory frequency and end expired volume were measured with a water spirometer. When they breathed close to TLC the rate of clearance increased (k = 4.62 +/- 1.03%/min) compared with breathing close to RV (k = 1.96 +/- 0.5%/min). This effect of changing volume was immediately reversible after adopting each new lung volume. There were no significant changes in tidal volume or respiratory frequency between each 5 min period. There was no significant difference between the clearance increased (k = 4.62 +/- 1.03%/min) compared with breathing close to RV (k = 1.96 +/- 0.5%/min). This effect of changing volume was immediately reversible after adopting immediate and reversible.

Administration, Inhalation↗
PubMed1987

Treatment of primary pulmonary hypertension intravenous epoprostenol (prostacyclin).

Ten patients with severe primary pulmonary hypertension and pronounced disability who were unresponsive to oral vasodilators were treated with intravenous epoprostenol (prostacyclin). All had been referred for heart and lung transplantation. Short term administration of epoprostenol (mean dose 5.5 ng/kg/min) increased the mean cardiac index from 1.8 to 2.2 1/min/m2, improved pulmonary artery oxygen saturation from 48% to 57%, and increased calculated tissue oxygen delivery from 10 to 11.8 ml/kg/min. The mean pulmonary vascular resistance fell by 18% while mean systemic artery pressure fell by 32%. Pulmonary artery pressure rose in only two patients. Continued intravenous infusion of epoprostenol for 1-25 months was associated with subjective and clinical improvement. Exercise tolerance improved as measured by an increase in the maximum rate of oxygen consumption during progressive exercise testing. In those six patients who were able to exercise before treatment it rose from a mean of 7 to 15 ml/kg/min. Those who had been unable to exercise before treatment achieved comparable rates of oxygen consumption after treatment. Two patients died on treatment, three have undergone heart-lung transplantation, and in five the treatment is continuing. Complications included episodes of septicaemia and ascites. In this uncontrolled study of patients with severe pulmonary hypertension epoprostenol seemed to offer a means of optimally dosing the patients with a vasodilator to reduce pulmonary vascular resistance and thus increasing cardiac output and oxygen tissue delivery. There was no evidence to suggest that this treatment influenced the progress of the disease.

Adolescent↗
PubMed1987

Mushroom compost worker's lung.

This study draws attention to difficulties in the diagnosis and the understanding of the mechanism of action of mushroom compost worker's lung. Descriptions are given of 4 workers in one factory who developed acute respiratory failure within a 6-month period; 13 others who were unaffected were also studied. Serological investigation appears to be largely unhelpful, and the evidence against the condition being included amongst the extrinsic allergic alveolitides is discussed. A detailed clinical and occupational history is essential for diagnosis.

Adolescent↗
PubMed1987

Anticholinergics and cough.

Ultrasonically nebulized aqueous aerosols enable the study in man of vagal epithelial rapidly adapting receptors. Inhalation of aerosols with low chloride ion concentration causes cough. Bronchodilatation in normal subjects using either inhaled fenoterol or ipratropium inhibits this reflex induced cough. It suggests that pulmonary stretch receptors (slowly adapting receptors) may play a part in modulating the cough reflex in man as has been suggested in cats and rabbits.

Administration, Inhalation↗
PubMed1986

Chemical specificity of coughing in man.

The purpose of this study was to test whether cough response to inhaled ultrasonically nebulized fluid is dependent on the ionic content of the fluid. Coughing was recorded in human volunteers during inhalation of aqueous solutions in a series of double blind randomized experiments. The occurrence of cough was found to be dependent on the concentration of chloride ions in the inhaled fluid, cough frequency progressively increasing as chloride ion concentration was reduced. It is proposed that the ion composition of the surface lining fluid of the airway may moderate the cough response by means of a chemo-receptor, although tonicity may also be important.

Acetates↗
PubMed1985

Nicotine and cigarette smoking: an alternative hypothesis.

A new hypothesis is presented to explain some aspects of human smoking behaviour. While acknowledging the importance of the nicotine self-titration phenomenon, changes in puffing intensity during the smoking of a single cigarette are related not to the control of nicotine uptake but to the modification of cigarette smoke composition prior to inhalation. It is suggested that nicotine, in addition to its central effects, has the local action of reducing the acute airway response to irritant components of cigarette smoke. The new hypothesis explains some of the 'anomalous' results of smoking behaviour research, and has implications both for cigarette design and for the recommendations made to smokers by statutory health agencies.

Bronchi↗
PubMed1985

The effect of surgery with cardiopulmonary bypass on alveolar-capillary barrier function in human beings.

We measured the rate of clearance of technetium 99m-labeled diethylenetriamine pentaacetate (99mTcDTPA) (molecular weight, 492 daltons) from the lung into the blood (T1/2LB) in 9 patients before and after operation with cardiopulmonary bypass (CPB). Two hours postoperatively, T1/2LB fell from 49.3 +/- 13.6 minutes (mean +/- standard deviation) to 24.0 +/- 12.8 minutes (p less than 0.001). In addition, alveolar-arterial oxygen tension difference P(A-a)O2 had increased from 73 +/- 28 mm Hg to 164 +/- 37 mm Hg (p less than 0.001). The rates of clearance of 99mTcDTPA had returned to preoperative times by 7 days after operation, although there was still a significant (p less than 0.05) elevation in P(A-a)O2. Postoperative respiratory failure developed in 1 patient. The only abnormality of lung function detected preoperatively was an increased clearance rate for 99mTcDTPA (T1/2LB, 18 minutes). This study has shown an increased clearance from the lung of a low-molecular-weight molecule following operation with CPB. This finding should allow a more rational approach to elucidating the mechanisms of injury to the gas-blood interface in the lung following this type of operation.

Aged↗
PubMed1984

Sustained release theophylline in nocturnal asthma.

Twice daily sustained release theophylline gave satisfactory steady serum theophylline concentrations in asthmatic children aged 7 to 14 years. The children showed improvement in symptoms, less frequent waking at night, reduced use of beta agonist inhalers, and improved early morning peak flows while being treated with this preparation. There was no improvement in peak flow at other times, but the patients recorded increased use of beta agonists during the placebo period.

Adolescent↗
PubMed1983

Tar, nicotine, and carbon monoxide yields of some Nigerian cigarettes.

Fourteen cigarette brands manufactured in Nigeria in 1981 were analysed to determine the tar, nicotine, and carbon monoxide yields. Five of the brands belonged to the high and middle to high tar category (greater than 22 mg/cigarette) and nine to the middle tar (17-22 mg/cigarette) category. None of the cigarettes was in the low to middle and low tar (less than 17 mg/cigarette) category. The nicotine and carbon monoxide yields were similar to those of European cigarettes. Tobacco companies need to manufacture low tar cigarettes in the Third World as is the practice in the economically developed parts of the world.

Carbon Monoxide↗