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Biomedical subjects

R E Ruffin

Publications and source records attributed to R E Ruffin.

At least 73 records · Page 4Linked to original sources
PubMed1987

The efficacy of nedocromil sodium (Tilade) in asthma.

Nedocromil sodium is a new antiasthmatic drug with properties similar to sodium cromoglycate. We examined the efficacy of nedocromil sodium compared to placebo in 71 asthmatic patients in a three-centre double-blind parallel group study over 12 weeks. During the study the patients' maintenance inhaled corticosteroids were progressively withdrawn. Nedocromil sodium had an advantage over placebo in the number of withdrawals related to uncontrolled asthma, 14 and 24 respectively (p = 0.03). Changes in symptom scores, peak flow rates and bronchodilator use favoured nedocromil sodium occasionally during the study. The unusual taste of the active drug was reported frequently. Nedocromil sodium is more efficacious than placebo in asthma maintenance, but does not replace inhaled corticosteroids.

Administration, Inhalation↗
PubMed1986

The effect of bucindolol on the airway function of asthmatics.

The airway and cardiovascular effects of separate single oral doses of 50, 100 and 200 mg of bucindolol were compared to those of placebo in a double-blind trial in 16 patients with mild to moderately severe asthma. Heart rate (HR), blood pressure (BP), forced vital capacity (FVC), forced expired volume in one second (FEV1), maximum expiratory flow at 50% of vital capacity (FEF50) and maximum expiratory flow at 75% of expired vital capacity (FEF75) were measured before and at intervals for 4h, when salbutamol (200 micrograms) was inhaled and the measurements repeated 15 min later. There was an interval of at least 4 days between each drug treatment day. Four of the 16 patients developed clinically significant bronchoconstriction with 50 mg (3) or 100 mg (1) of bucindolol and were withdrawn from the study. The remaining patients showed impaired bronchodilator response to salbutamol for each bucindolol dose as compared to placebo. No significant BP or HR effects were measured. Two patients withdrew because of circumstances unrelated to bucindolol induced bronchoconstriction. The development of bucindolol induced bronchoconstriction in this group of mild to moderate asthmatics was not predicted by the level of baseline pulmonary function, or the level of histamine responsiveness. However, there was a weak relationship between bucindolol induced bronchoconstriction and salbutamol induced bronchodilation. There are no definitive asthmatic characteristic to predict the likelihood of significant bucindolol induced bronchoconstriction in this asthmatic population.

Adult↗
PubMed1986

The prevalence rate of respiratory symptoms in school children from two South Australian rural communities.

The respiratory symptoms and respiratory function of 680 schoolchildren from two rural area of South Australia were studied. The initial results of this prospective, longitudinal study showed that the cumulative prevalence of asthma and/or wheezy breathing was 27.4% in the Burra population and 23.1% in the Kingston population. The cumulative prevalence of one or more attacks of asthma/wheezy breathing amongst Burra (38.8%) and Kingston (23%) children aged up to 8 years was significantly higher than that reported for urban Melbourne children (11%, p less than 0.01). The combined South Australian group reported a cumulative prevalence of asthma/wheezy breathing alone of 10% which was significantly higher than the cumulative prevalence rates in three previous studies reported in Australia (1.8%, 2.6%, 2.7%, p less than 0.01). The highest overall cumulative prevalence of bronchitis/loose or productive cough occurred in the 12 year old Burra children (41.5%). Burra girls had the highest prevalence of bronchitis/loose or productive cough (36.8%) compared to other groups studied at both locations. The parental smoking rate (60.4% in Burra, 57.4% in Kingston) is much higher than the national figure reported by the Bureau of Statistics in 1977 (35.9%). The prevalence of asthma/wheezy breathing is much higher in the South Australian cohort compared to the Queensland and Tasmanian cohorts studied using the same questionnaire. Predicted respiratory function parameters using initial algorithms are similar to those reported for urban Australian children.

Adolescent↗
PubMed1982

Combination bronchodilator therapy in asthma.

This study has compared the short-term bronchodilator effects of inhaled anticholinergic (ipratropium bromide) and sympathomimetic (fenoterol) agents alone and in combination in 18 asthmatic patients. the study was of double-blind, placebo-controlled, crossover design. The combination of 60 micrograms ipratropium bromide and 200 micrograms of fenoterol had a greater bronchodilator effect than lower dose combinations or either drug alone. Small but significant gains may be made with combination inhaled bronchodilator therapy.

Adult↗
PubMed1982

Assessment of beta-adrenoceptor antagonists in asthmatic patients.

1 Bronchial smooth muscle, skeletal muscle and cardiac beta-adrenoceptor antagonism have been compared in twelve asthmatic patients after three beta-adrenoceptor antagonists at two dose levels. The non-selective antagonist propranolol (40 and 160 mg), the non-selective antagonist with partial agonist activity pindolol (5 and 20 mg) and the beta 1-selective antagonist atenolol (50 and 200 mg) were studied on separate occasions. 2 Six placebo days were used in this double-blind crossover study to allow interpretation of individual as well as group results. 3 Bronchial smooth muscle effects were assessed by resting spirometry, histamine inhalation test and spirometric response to inhaled fenoterol. Skeletal muscle effects were assessed by resting tremor and fenoterol induced tremor. 4 Cardiac beta-adrenoceptor antagonism was assessed by measuring the effect on resting heart rate and on maximum heart rate in a standard exercise test. 5 Pindolol tended to cause least change from placebo in resting spirometry, caused significant tremor response, inhibited the fenoterol airway response, and tended to protect against inhaled histamine. 6 Atenolol 60 mg was the only drug to allow a fenoterol airway response similar to placebo. Atenolol increased the inhaled histamine responsiveness. 7 Propranolol 160 mg caused the most reduction in spirometry but also tended to cause the maximum reduction in exercise heart rate. Propranolol caused increased inhaled histamine responsiveness. 8 Initial sensitivity to inhaled histamine did not necessarily predict significant reduction in an asthmatics' spirometry by a beta-adrenoceptor antagonist. The effect of a beta-adrenoceptor antagonist on histamine responsiveness does not correspond to its effect on inhaled beta 2-adrenoceptor agonist responsiveness.

Adrenergic beta-Antagonists↗
PubMed1981

Repeated histamine inhalation tests in asthmatic patients.

Histamine inhalation tests were performed in 12 asthmatic patients using a 2-min tidal breathing inhalation technique. The tests were repeated on separate days with 30-, 60-, and 120-min intervals between inhalation tests. On another day the inhalation tests were repeated four times with 40-min intervals between tests. The geometric mean provocative concentrations of histamine needed to cause a 20% fall in forced expiratory volume in 1 sec (PC20) for the group on the latter study day were 1.67, 1.57, and 1.55 mg/ml (p greater than 0.25) indicating no change in sensitivity to inhaled histamine with repeated testing. The results suggest that cumulative dose-response curves for drugs potentially affecting the airways or antagonizing histamine can be constructed within 1 day using histamine inhalation tests. The data also suggested that an individual PC20 result may be sensitively assessed by comparing it to a +/- 2 SD range from the mean of a series of control or placebo PC20 values.

Adult↗
PubMed1981

Inhibition of allergen-induced asthma by three forms of sodium cromoglycate.

The effect of three forms of sodium cromoglycate (SCG), 20 mg, on allergen-induced early asthmatic responses was examined in ten stable asthmatics. Dose response allergen inhalation tests were performed on five occasions at intervals of from 1 to 2 weeks to determine the provocation concentration producing a 20% reduction (PC20 allergen) in FEV1. Placebo was given before the first and the last tests to determine the reproducibility of responses to allergen over the study period; reduced responsiveness was observed in eight of the ten subjects. Major changes in levels of specific serum antibodies of the IgE and IgG classes did not serve to explain the changes in bronchial responses although there was a trend which suggested IgG-related desensitization. The observed changes in bronchial responses and antibody levels illustrate the requirement for tests of reproducibility of responses by the use of placebo controls at the beginning and end of a series of allergen inhalation challenges. SCG as (i) a micronized powder with lactose, (ii) micropellets without lactose, or (iii) an aerosol, were inhaled double-blind, in random order, 5 min before the additional three allergen inhalation tests. PC20 allergen was reduced following SCG in seven subjects; the differences were statistically significant for the group. There was no observed difference in efficacy between the different forms of SCG. In this study, the efficacy of SCG could not be related to age, atopic status, the initial level of allergen-specific IgE antibody, baseline FEV1, level of bronchial responsiveness to inhaled histamine or an effect of SCG on responsiveness to histamine.

Adolescent↗
PubMed1981

The preferential deposition of inhaled isoproterenol and propranolol in asthmatic patients.

This study describes the use of central and diffuse airway deposition patterns of isoproterenol and radiotracer aerosol alone, and in the presence of centrally deposited propranolol and radiotracer aerosol, to investigate the distribution of beta 2 adrenoreceptors in six asthmatic patients. The central deposition technique was only partially successful. No definite beta 2 receptor distribution pattern could be interpreted from the airway function responses. It was noted that 3-10 micrograms of isoproterenol in the airways was able to produce 50 percent of the maximum possible flow rate response. Centrally deposited propranolol was an effective antagonist of isoproterenol.

Adult↗
PubMed1980

Immotile cilia syndrome in persons with and without Kartagener's syndrome.

We studied the ultrastructure and function of respiratory tract cilia in a group of patients with Kartagener's Syndrome, and compared the results with those from a group of subjects with unexplained histories of chronic bronchiectasis and bronchitis. Both patient groups lacked pulmonary and nasal mucociliary transport. On electron microscopic examination of nasal mucosal biopsy tissue, all patient specimens had abnormal cilia with a highly disorganized microtubular network, and a consistent absence of dynein arms. Cilia from both groups were immotile when viewed under direct phase contrast, but could be animated by the addition of 10(-6) g/ml of ATP or ATPase to the same degree of spontaneous motility seen in normal cilia. Immotile cilia syndrome clearly includes not only patients with Kartagener's syndrome, but also some patients with chronic bronchitis and bronchiectasis.

Adenosine Triphosphatases↗
PubMed1979

Selectivity of beta adrenoreceptor antagonist drugs assessed by histamine bronchial provocation.

In a double-blind, within-patient, randomized study, 12 mild asthmatics were given single oral doses of propranolol (80 mg), metoprolol (100 mg), timolol (10 mg), or placebo. Resting heart rate and forced expiratory volume in one sec (FEV1) were measured before and 90 min after treatment. Nonspecific bronchial reactivity was measured by inhaled histamine at 90 min. Following each active drug, resting heart rate changed to a similar extent and to a greater degree than after placebo (p less than 0.01). Changes in FEV1 were small and not different from those after placebo. In contrast, after each active drug, bronchial reactivity increased more than after placebo. The degree of reactivity with each active drug was similar but the differences from corresponding placebo values were significant (p less than 0.05). We conclude that, in mild asthmatics, nonspecific bronchial reactivity is a more sensitive index of airway effects than resting FEV1. Moreover, in the context of this study, since the beta-blockers were given in doses likely to induce equivalent cardiac beta-blockade, there is no evidence to suggest that any one of them is more "cardioselective" than the others.

Adolescent↗
PubMed1979

Aerosol fenoterol by intermittent positive pressure breathing in asthmatic patients.

Ten subjects with mild to moderately severe asthma participated in a study of the bronchodilator activity and incidence of side effects of fenoterol aerosol administered by intermittent positive pressure breathing (IPPB). The doses of fenoterol used in the Bird micronebulizer were 0, 0.25 mg, 0.5 mg, 1.0 mg, and 2.5 mg, and these were administered in a randomized, double-blind fashion. The bronchodilator response, assessed by the area under the FEV1 curve, showed mean (+/- SE) values of 1.44 +/- 0.53 1 hr for 0.25 mg of fenoterol to 1.66 +/- 0.56 1 hr for 2.5 mg of fenoterol (p greater than 0.05), longer (p less than 0.01) than the mean placebo response of 0.06 +/- 0.38 1 hr. A dose-dependent increase in tremor was observed for each of the doses of fenoterol. The 0.25-mg dose of fenoterol solution is an appropriate starting dose for the treatment of moderately severe asthma.

Adult↗
PubMed1979

Bronchial reactivity in Western red cedar induced asthma.

A patient with Western red cedar induced asthma is described. The diagnosis was confirmed by a bronchial challenge with Western red cedar saw dust and the subsequent prolonged bronchial reactivity changes were measured using histamine inhalation tests.

Asthma↗