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Biomedical subjects

M Newhouse

Publications and source records attributed to M Newhouse.

At least 19 recordsLinked to original sources
PubMed1996

Efficiency of aerosol medication delivery from a metered dose inhaler versus jet nebulizer in infants with bronchopulmonary dysplasia.

The best means for optimal delivery of drugs into lungs of infants with bronchopulmonary dysplasia (BPD) is uncertain. We aimed to measure radio-aerosol deposition of salbutamol by jet nebulizer and metered dose inhalers (MDI) in ventilated and non-ventilated BPD infants. In a randomized, crossover sequence, salbutamol lung deposition was measured using an MDI (2 puffs or 200 micrograms) or sidestream jet nebulizer (5 minutes of nebulization with 100 micrograms/kg) in 10 ventilated (mean birthweight, 1,101 g) and 13 non-ventilated (mean birthweight, 1,093 g) prematurely born infants. Non-ventilated infants inhaled aerosol through a face mask, connected to a nebulizer or an MDI and spacer (Aerochamber). Ventilated infants received aerosol from an MDI + MV15 Aerochamber or a nebulizer inserted in the ventilator circuit. Lung deposition by both methods was low: mean (SEM) from the MDI was 0.67 (0.17)% of the actuated dose, and from the nebulizer it was 1.74 (0.21)% and 0.28 (0.04)% of the nebulized and initial reservoir doses, respectively. Corresponding figures for the ventilated infants were 0.98 (0.19)% from the MDI and 0.95 (0.23)% and 0.22 (0.08)% from the nebulizer. In both groups, and for both methods of delivery, there was marked inter-subject variability in lung deposition and a tendency for the aerosol to be distributed to the central lung regions.

Aerosols↗
PubMed1994

Effect of increasing doses of beta agonists on spirometric parameters, exercise capacity, and quality of life in patients with chronic airflow limitation.

BACKGROUND: A study was undertaken to determine the impact of different doses of inhaled terbutaline on peak flow rates, spirometric parameters, functional exercise capacity, and quality of life in patients with chronic airflow limitation. METHODS: A double blind, randomised, placebo controlled, multiple crossover trial was conducted with treatment periods of one week. Patients with a clinical diagnosis of chronic airflow limitation and FEV1 below 70% predicted after administration of bronchodilator were recruited from secondary care respiratory practices, and the effect of 500, 1000, and 1500 micrograms inhaled terbutaline four times daily on spirometric parameters (FEV1, FVC), maximum inspiratory pressures, six minute walking distance, and health-related quality of life (Chronic Respiratory Disease Questionnaire, Quality of Well Being, Standard Gamble) was measured. RESULTS: Twenty five patients completed the trial. Peak flow rates and FEV1 showed statistically significant but clinically trivial improvement on the higher drug doses. Results of maximum inspiratory pressure measurements, walk test distance, and quality of life measures showed minimal differences on the different dosages, and none of the differences approached conventional statistical significance. CONCLUSIONS: Regular use of beta agonists in doses higher than two puffs four times a day is very unlikely to provide additional functional or symptomatic benefit to patients with chronic airflow limitation.

Aged↗
PubMed1992

The effect of the synthetic retinoid etretinate on sputum cytology: results from a randomised trial.

Laboratory studies, and one previous uncontrolled trial, have suggested that retinoids may reverse bronchial atypia, a putatively premalignant condition. Sputum sampling is a simple, non-invasive method of assessing atypia. Smokers with at least a 15 pack-year history were screened for sputum atypia. One hundred and fifty subjects' were randomised to receive the synthetic retinoid etretinate 25 mg orally or identical placebo daily for 6 months. Compliance was measured by performing pill counts and serum sampling every 2 months for etretinate levels. The outcomes assessed were, improvements in sputum atypia and toxicity. At baseline there was no significant difference between the two groups with respect to gender, smoking history or extent of atypia. Four of 75 subjects on etretinate and six of 75 on placebo dropped out before 6 months. Compliance as measured by pill counts and etretinate levels was high. Eighty-six per cent of subjects on etretinate took 90% or more of their prescribed medication and etretinate was detected in 245 of 264 samples. By contrast etretinate was detected in only six of 266 samples in the control group and probably did not represent true contamination. After 6 months on etretinate there was no difference in the degree of atypia between the two treatment arms. Toxicity was mild in both groups with considerable placebo effect noted. Etretinate, at the dose used in this study, had no impact on sputum atypia as detected by sputum sampling.

Administration, Oral↗
PubMed1992

Controlled trial of respiratory muscle training in chronic airflow limitation.

BACKGROUND: Whether respiratory muscle training is of benefit to patients with chronic airflow limitation is controversial. The objective of the study was to determine the effect of resistance breathing training on physiological and functional measures in patients with chronic airflow obstruction. METHODS: The design was a randomised, double blind, controlled trial with a six month follow up. Eighty two patients with a forced expiratory volume in one second (FEV1) of less than 70% predicted, and an FEV1/vital capacity ratio of less than 0.7, were randomised to receive training for 10 minutes five times daily with progressively larger resistances through a resistive breathing device (PFLEX) as tolerated or to a sham device which gave minimal resistance. The main outcome measures, respiratory muscle strength and endurance, a progressive exercise test, a six minute walk test and physical and emotional function (chronic respiratory questionnaire) were assessed at monthly intervals. Patients in both groups were also randomised to wear or not wear nose clips during their training. RESULTS: No significant differences were observed between treatment and control groups, with or without nose clips, for any of the outcomes. Confidence intervals on the difference between treatments were narrow, excluding clinically important difference in any major outcome. CONCLUSION: This training regimen fails to strengthen respiratory muscles or improve exercise or functional capacity in patients with chronic airflow limitation.

Aged↗
PubMed1991

Advantages of pressurized canister metered dose inhalers.

Metered dose inhalers (MDI) have provided a versatile, reliable, instantly available, self-contained, portable, low cost medical aerosol delivery system for more than 35 years. Currently, most of the drugs commonly used for treating reversible airflow obstruction due to asthma and chronic obstructive pulmonary disease (COPD) are available as MDI and consideration is being given to formulating other potentially useful drugs such as antibiotics, amiloride, and pentamidine in MDI. By means of particle size selective accessory devices, MDI can be used for pulmonary drug targeting which, by further improving the therapeutic ratio inherent to aerosol therapy, reduces local and systemic side effects and should allow application to the pulmonary airways of significantly larger doses of medication than could otherwise be administered safely. Appropriate masks and a variety of adapters have been developed to allow the MDI to be used in infants and children, as well as patients of all ages requiring assisted ventilation. While nebulizers and powder inhalers both have an important role to play in the management of airway and parenchymal disease, there is, as yet, no all-purpose aerosol generation and delivery system to replace the MDI. While the ideal is obviously to develop new environmentally friendly pressurizing liquid/gaseous systems that are chlorofluorocarbon free, this will take a minimum of a decade if, in the final analysis, it can be done at all. In the meantime, patients should be provided with the current formulations until appropriate substitutes become available.

Administration, Inhalation↗
PubMed1987

Lung epithelial permeability in sarcoidosis.

Sarcoidosis is a multisystem disease with a 90% prevalence of lung involvement. It is now accepted that lymphocytes play a major modulatory role in the pathogenesis of this disease. However it has become evident in recent years that a number of other inflammatory cells capable of releasing mediators which can cause lung injury are involved as well. Although sarcoidosis is a relatively benign disease, it is well recognized that about 25% of the patients, perhaps those with unresolved injury, experience a relentless course and ultimately die from the disease. The rate of absorption from the lung of 99m Tc-DTPA is influenced by the integrity of the pulmonary epithelium, which might be altered as a result of injury to the lung. Several groups have measured 99m Tc-DTPA absorption in patients with sarcoidosis and have shown that it was increased in more than 50% of the patients studied. This abnormality seemed to prevail in patients with more advanced disease and in those who did not show a benign course. Whether a persistent increase in the rate of absorption of 99m Tc-DTPA reflects current or unresolved lung injury is unclear. The possibility of this technique being useful in monitoring the course of sarcoidosis deserves attention and should be further explored.

Epithelium↗
PubMed1986

Aerosol therapy of asthma: principles and applications.

Aerosols are the mainstay of therapy of reversible airflow obstruction. Currently available aerosols include bronchodilators such as beta-adrenoceptor agonists and anticholinergic agents which may be used alone or together with prophylactic, anti-inflammatory medications such as sodium cromoglycate and steroids. These agents are characterized by primarily topical activity and thus result in minimal systemic effects. By combining these medications in optimum doses, most patients can be readily managed. In patients with severe airway hyperreactivity, aerosols may need to be combined with oral sustained-release theophylline compounds and/or systemic steroids, the latter being used in minimum doses and if possible on alternate days to minimize adrenal suppression and steroid-related systemic complications. In recent years, an improved understanding of aerosol physics, pharmacology and airway physiology has led to greatly improved aerosol therapy with increasing emphasis on metered dose inhalers as the delivery system of choice while nebulizers are used less frequently except in hospital and pediatric applications. The use of intermittent positive-pressure devices for aerosol delivery has decreased considerably as physicians recognize that simpler delivery methods work equally well at much lower cost. While aerosol therapy techniques are now well worked out, research is continuing on methods of improving the efficiency of aerosol delivery and in the development of newer pharmacological agents such as longer-acting adrenoceptor agonists, calcium channel blockers, antagonists of mediators derived from arachidonic acid as well as higher dose aerosolized steroids.

Aerosols↗
PubMed1983

[Ventilation scintigraphy of the lung with 99mTc-DTPA or with 99mTc-sulfur colloid?].

Ventilation scintigraphy of the lung, obtained with sufficiently small 99mTc-labelled aerosol particles, provides an image of ventilation distribution that is acceptable in clinical routine. Whether 99mTc-DTPA or 99mTc-sulfur colloid is more suitable as a carrier was studied in 6 smokers and 8 non-smokers with chronic obstructive pulmonary disease. 99mTc-sulfur colloid was not absorbed by the bronchial mucosa and therefore appears to be an almost ideal agent. In contrast, 99mTc-DTPA was absorbed by the bronchial mucosa in all smoking patients more rapidly and inhomogenously than in non-smokers. The quantitative and qualitative comparison of the two dorsal ventilation scans taken both immediately after inhalation and 20 min later, showed in all 6 smoking patients after 20 min significant differences which influenced the diagnosis result. 99mTC-DTPA is therefore not recommended for use in ventilation lung scintigraphy, especially in smoking patients.

Adolescent↗
PubMed1981

Epidemiology of asbestos-related tumors.

Epidemiologic evidence has helped in defining and measuring the risks of asbestos exposure. Further investigations are required to confirm the differing carcinogenicity of the various types of asbestos and related fibers. The evidence relating crocidolite asbestos to malignancy is not universally accepted. Most standards for concentrations of asbestos in the air are currently being adopted and the proposed British standard is about to be reduced to 1 fiber per milliliter for chrysotile asbestos, 0.5 fiber per milliliter for amosite and is to remain at 0.2 fiber per milliliter for crocidolite asbestos. 37 Careful prospective studies are still required in order to evaluate the efficacy of these standards in the prevention of asbestos related diseases. In addition, further epidemiologic studies are necessary to determine the relationship between asbestos exposure, particularly the low level exposure, and its potential cocarcinogenic role with other carcinogens in the evolution of the wide spectrum of human malignancy.

Asbestos↗
PubMed1978

Percutaneous paraquat absorption. An association with cutaneous lesions and respiratory failure.

Striking cutaneous lesions and death owing to respiratory failure occurred in a middle-aged woman eight weeks after initial cutaneous contact with the herbicide paraquat (1,1'dimethyl-4,4'dipyridylium dichloride). While similar changes have been described in animals, to our knowledge, serious morbidity or mortality owing to percutaneous absorption has not been described in man. This case report illustrates the extreme toxicity of this herbicide and demonstrates that lethal quantities of the drug may be absorbed from apparently trivial skin wounds. Stricter precautions, including the mandatory use of protective clothing, should be recommended whenever this material is used.

Accidents↗
PubMed1977

Cystic fibrosis--related inhibition of mucociliary clearance in vivo in man.

Studies were performed to demonstrate possibly cystic fibrosis-related inhibition of mucociliary clearance in man. Topical application of normal serum or of CF serum did not inhibit in vivo nasal MCC. Induction of local inflammation by topical anti-IgE-reduced nasal MCC in CF subjects, but increased MCC in normal individuals. Furthermore, nasal MCC was inhibited in normal patients by CF serum but not normal serum, applied to the anti-IgE-treated nasal mucosa. These observations are consistent with the hypothesis that CF serum inhibits MCC in vivo in the inflamed mucosa.

Adolescent↗