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Biomedical subjects

R Dahl

Publications and source records attributed to R Dahl.

At least 163 records · Page 9Linked to original sources
PubMed1991

Effect on smoking cessation of silver acetate, nicotine and ordinary chewing gum. Influence of smoking history.

In a randomized smoking cessation study 211, 203 and 82 persons were supported with nicotine, silver acetate and ordinary chewing gum, respectively. After 26 weeks there was no overall difference in number of abstainers between treatments. Participants were divided into subsets with low and high weighted packyears consumption (WPY) which modifies tobacco consumption by nicotine content. Abstainer rates in the total population controlled for treatment decreased with increasing WPY (P less than 0.005). In participants with low WPY abstainer rate was higher in the silver acetate group compared to the nicotine (P less than 0.0005) and ordinary (P less than 0.05) chewing gum groups. Nicotine chewing gum was more effective than silver acetate (P less than 0.05) and ordinary (P less than 0.05) chewing gum in smokers with high WPY. Ratings on some inconveniences experienced during earlier attempts to quit smoking influenced the ability to break the habit but had no influence on chewing gum effects. This study indicated that through consideration of smoking history it should be possible to individualize pharmacological support to smokers wanting to quit, with silver acetate chewing gum most effective for smokers with a low WPY and nicotine chewing gum most effective for smokers with a high WPY.

Acetates↗
PubMed1991

Treatment of chronic bronchitis with terbutaline inhaled from a cone spacer with and without positive expiratory pressure.

Patients with chronic bronchitis were randomly allocated to 4 weeks treatment with terbutaline 0.5 mg inhaled through a cone spacer with an expiratory resistance creating a positive expiratory pressure (+PEP group) or without (-PEP group). The patients recorded their symptoms in a diary and peak expiratory flow (PEFR) was measured before and after each inhalation. PEFR increased significantly after inhaled terbutaline both with and without PEP. The mean increase in PEFR after terbutaline inhalations was significantly greater (p less than 0.0001) in the +PEP group (24 L/min) compared to the -PEP group (17 L/min). The +PEP group had less sputum and less difficulty with coughing up sputum compared to the -PEP group. This study showed a small but significant enhancement of the bronchodilation and a beneficial effect on symptoms when inhalation of beta-2-agonist was combined with PEP in patients with chronic bronchitis.

Bronchitis↗
PubMed1991

Eosinophils in exercise-induced asthma.

The variations in serum levels of eosinophil cationic protein (ECP) have been measured after exercise challenge of 13 patients with asthma with exercise-induced asthma (EIA) and nine patients with asthma without EIA. The patients were treated before exercise in a randomized and blinded fashion with inhalation of one dose of either disodium chromoglycate, terbutaline, or budesonide and in an open study with 4 weeks of inhaled budesonide. In the group with EIA, there was, in some patients, an initial increase in serum levels of ECP after exercise, but 60 minutes after exercise, the levels were significantly reduced (p less than 0.001). Disodium chromoglycate and 4 weeks of budesonide treatment inhibited this reduction. Histamine challenge of the group with EIA produced a similar fall in serum ECP levels (p less than 0.001). The group without EIA had initially lower levels of ECP than the group with EIA (p less than 0.05 to p less than 0.01), and ECP stayed unaltered after exercise. The preexercise serum ECP levels correlated significantly to the maximal fall in peak expiratory flow in the untreated group (r = 0.91; p less than 0.001) and in the group receiving one dose of budesonide (r = 0.62; p less than 0.05). The blood eosinophil counts were unchanged after challenge and not related to lung function. The results suggest that the ECP content in serum reflects the degree of allergic inflammation in the lungs and thereby the degree of bronchial hyperreactivity.

Adolescent↗
PubMed1991

In-hospital sting challenge in insect venom-allergic patients after stopping venom immunotherapy.

Immunotherapy (IT) in venom-allergic patients has been demonstrated to provide a highly efficient protection from severe reactions to a re-sting. It is not known whether this protection will persist after IT is stopped in patients with remaining venom sensitivity. In 25 adult patients with a previous severe systemic reaction to a Hymenoptera insect sting, 28 in-hospital sting challenges after stopping IT resulted in no systemic reactions. The mean duration of venom IT was 42.8 months (range, 36 to 83 months), and the mean time interval from the time IT was stopped until sting challenge was, in mean, 25.2 months (range, 12 to 36 months). The mean venom-specific IgE after stopping IT was 2.4 PRU/ml (range, 0 to 16.9 PRU/ml), at the day of sting challenge, 2.7 PRU/ml (range, 0 to 22 PRU/ml), and 2 weeks later, 2.4 PRU/ml (range, 0.02 to 27.8 PRU/ml). These changes in IgE were not significant. Venom-specific IgG concentration when IT was stopped was 64 PU/ml (range, 20 to 144 PU/ml), decreasing significantly to the day of sting challenge to 41.1 PU/ml (range, 13 to 84 PU/ml), and 2 weeks later, a significant increase to a mean of 53.5 PU/ml (range, 12 to 117 PU/ml) was found. Our results suggest that venom IT may be stopped after 3 years, regardless of the level of specific antibodies. To confirm this finding, a larger number of patients should be studied.

Adult↗
PubMed1991

In vitro studies of the interaction between heparin and eosinophil cationic protein.

Eosinophil cationic protein (ECP) is a protein specific to the granules of human eosinophil granulocytes, ECP is highly cationic and may damage tissue if not inactivated. Heparin is a highly anionic substance present in mast cells and basophil granulocytes. The present in vitro study shows that ECP can inactivate the anticoagulant activity of heparin probably by the formation of a complex between the two molecules. This function may be of importance for the microenvironment of allergic diseases where secretion of heparin may promote penetration of mast cell products through tissues. Also this may constitute one mechanism whereby the cytotoxic action of ECP is neutralized.

Blood Coagulation↗
PubMed1991

Powder administration of pure budesonide for the treatment of seasonal allergic rhinitis.

The objective of this study was to compare the efficacy and safety of a pure powder formulation of budesonide, delivered from a new multi-dose dispenser for nasal drug application, with the commercially available budesonide pressurized aerosol, and with placebo. Of 116 patients with grass pollen-induced allergic rhinitis, 112 finished the study, which comprised a 4-week treatment period, preceded by a 1-week run-in period. The patients were randomized to four parallel treatment groups: budesonide powder 400 micrograms daily; budesonide powder 800 micrograms daily; budesonide aerosol 400 micrograms daily; and placebo powder. Treatment was given once daily in the morning. The study was double-blind regarding comparison between budesonide powder and placebo. Assessment of efficacy, made by comparing mean scores of nasal symptoms and use of rescue medication, showed equal efficacy of all three budesonide groups compared with placebo. There were no differences between budesonide-and placebo-treated groups with regard to side effects. Budesonide treatment had no demonstrable effect on the HPA-axis assessed by measurement of 24-h urine cortisol. We conclude that budesonide, delivered as pure powder from a multi-dose dispenser, is effective and safe for the treatment of seasonal allergic rhinitis. This new formulation is a good alternative to the commercially available preparations, as it does not contain carrier gas, preservatives or lubricants.

Administration, Topical↗
PubMed1991

Evidence that vesicles containing living, virulent Mycobacterium tuberculosis or Mycobacterium avium in cultured human macrophages are not acidic.

Mycobacterium tuberculosis and Mycobacterium avium multiply in cultured human macrophages (MP) within membrane-enclosed vesicles. These vesicles are generally assumed to be acidic. The evidence most frequently cited for this assumption is that pyrazinamide, which requires an acid pH to be effective, is effective and streptomycin, which loses most of its activity at a low pH, is poorly effective against tubercle bacilli. This assumption was tested by using the two weak bases chloroquine and NH4Cl to raise the pH of acidic vesicles in MP experimentally infected with M. tuberculosis or M. avium. An immunocytochemical locator of acidic regions in the MP was used to monitor the association of intracellular bacilli with acidity. MP were infected with M. tuberculosis or M. avium and incubated with various combinations of the drugs and the weak bases. Replication of the bacteria in the MP was measured by culture counts. Intracellular associations of the mycobacteria with acidity were assessed by electron micrographs and by using the weak base 3-(2,4-dinitroanilino)-3'-amino-N-methyl dipropylamine, which was detected with colloidal gold-labeled antibodies. It was confirmed by immunocytochemistry that both chloroquine and NH4Cl raise the pH of acidic vesicles in the infected MP. However, neither caused any pH-related change in the antimycobacterial activities of pyrazinamide or streptomycin or of the pH-independent drug isoniazid. Immunochemical analyses showed acidity to be associated with killed but not living mycobacteria in the MP. These findings suggest that living M. tuberculosis and M. avium are located in human MP in vesicles which are not acidic.

Ammonium Chloride↗
PubMed1991

Lung function and bronchial reactivity in asthmatics during exposure to volatile organic compounds.

The purpose of the present study was to investigate whether vapors of organic solvents at low concentrations could exert an adverse effect in the lower airways. Under controlled conditions in a climate chamber, 11 persons with bronchial hyperreactivity to histamine and bronchial asthma were exposed for 90 min to a mixture of organic solvents at levels of zero, 2.5, and 25 mg/m3. During exposure to 25 mg/m3 a decrease in FEV1 to 90.7% of baseline value was measured. This was significantly different from the initial value (p less than 0.05), but not significantly different from the value found after sham exposure (FEV1, 97.4% of initial value). The decline in FEV1 during exposure to 25 mg/m3 was most pronounced in persons with high bronchial sensitivity. No changes were found in histamine reactivity after exposure, and no late reactions were registered. Ratings of discomfort showed different individual patterns ranging from no response to reactions towards both of the concentrations. The ratings indicated development of tolerance during exposure. Volatile organic compounds in concentrations found in both the work and the home environments may influence lung function and are probably of importance as bronchial irritants.

Adult↗
PubMed1991

Treatment of bronchial asthma with terbutaline inhaled by conespacer combined with positive expiratory pressure mask.

The influence of positive expiratory pressure (PEP) applied during inhalation of a beta 2-agonist in treatment of bronchial asthma was investigated in a randomized crossover study with two-week treatment periods. In one period, two puffs (0.5 mg) of terbutaline was given from a metered dose inhaler and inhaled through a device consisting of a conespacer connected to a facemask giving PEP (10 to 15 cm H2O). In a second period, terbutaline 0.5 mg was inhaled similarly but without PEP, and in a third period placebo spray was inhaled with PEP. Treatments were given three times daily. Peak expiratory flow (PEF) was measured before and after each inhalation and symptom scores for dyspnea, cough, and mucus production were noted in a diary. All treatments increased PEF significantly (p less than 0.0001). The mean increase was 32 L/min during treatment with terbutaline and PEP. This was greater than the increase of 25 L/min during terbutaline treatment (p = 0.005). The increase in PEF during terbutaline treatment was significantly higher than the achieved 18 L/min during PEP (p = 0.026). The study showed improved bronchodilation when PEP was combined with inhalation of beta 2-agonist compared with beta 2-agonist alone.

Adult↗
PubMed1991

The effect of nicotine, silver acetate, and placebo chewing gum on the cessation of smoking. The influence of smoking type and nicotine dependence.

The effects of nicotine (NI), silver acetate (SA), and ordinary (PL) chewing gum on the cessation of smoking were compared through ratings on six smoking types and physiological nicotine dependence (F-score) in a placebo-controlled and randomized study that included 496 smokers in a group-support setting. Results were evaluated after 26 weeks. Ratings on smoking types 1, 3, 4, 5, and 6 and F-score were related to success rates. The effect of NI was superior to SA in smokers with high type 1 ratings, the effects of NI and SA were almost equal and superior to PL in smokers with high type 4 and 6 ratings, and the effect was independent of the F-score. Treatment of smokers with NI and SA should be restricted to smoking types in which an effect superior to PL is documented, and research should be performed to find support for smoking types where SA and NI have a clear effect.

Acetates↗
PubMed1991

Salmeterol: a four week study of a long-acting beta-adrenoceptor agonist for the treatment of reversible airways disease.

A total of 1,068 patients, aged 18-70 yrs, with mild to moderate reversible airways disease, were recruited into a multicentre, double-blind, parallel group study in 76 European centres. Following a 2 week run-in period, the 692 patients fulfilling the entry criteria were randomized to 4 weeks treatment with either salmeterol 12.5, 50 or 100 micrograms or placebo b.d. all given by pressurized inhaler, with assessments of symptoms and ventilatory lung function prior to dosing. All three doses of salmeterol had significant efficacy, manifested by increased morning and evening peak expiratory flow rate (PEFR) (by 35-59 l.min-1 and 11-38 l.min-1, respectively), by reduced diurnal variation in PEFR, and by reduced requirement for additional bronchodilator for symptomatic relief. These effects were dose-related. Daytime asthma symptoms and nocturnal awakenings were significantly reduced by salmeterol treatment, although these reductions were not dose-related. The incidence of adverse events was low. Pharmacologically predictable events (e.g. tremor) were more frequent after treatment with 100 micrograms b.d. than with placebo. On the basis of the efficacy and side-effect information, 50 micrograms b.d. is considered to be the optimum dose for the treatment of this group of asthmatics.

Administration, Inhalation↗
PubMed1991

The eosinophil.

There is controversy on functions, ranging from protective, tissue protecting to aggressive tissue damaging effects. High numbers are found in many diseases. The cell is invariably seen when helminths invade tissues, with numbers correlated with IgE titres and it is the major cytotoxic cell for parasitic larvae. It is produced by bone marrow, and controlled by T cell products and other mediators. A fundamental connection exists between asthma and eosinophils irrespective of the presence of an allergic factor. Study of sputum samples is of more value than blood eosinophil numbers. After allergen challenge there may be both immediate and late reactions. Where the late reaction occurs blood eosinophil numbers rise, indicating a central position in the pathogenesis. Cellular proteins and extracellular products and their effects are tabulated. The cells are heterogenous into two types, normodense (low activity) and hypodense which have high activity of increased secretory activity, chemotactic response etc. Treatments for asthma and beta-2-agonists and corticosteroids inhibit mediator release and eosinophil numbers and the abnormality should be considered early.

Asthma↗
PubMed1991

Nebulized terbutaline and positive expiratory pressure in chronic obstructive pulmonary disease.

The effect of positive expiratory pressure (PEP) and inhaled terbutaline was evaluated in ten patients with chronic obstructive pulmonary disease in a randomized cross-over study with three 2 weeks periods. In one period 5 mg terbutaline was inhaled 3 times daily from a nebulizer combined with PEP. In a second period 5 mg terbutaline was inhaled similarly but without PEP and in a third period placebo inhalations were combined with PEP. Symptom score and peak expiratory flow (PEF) measured before and after each inhalation was noted in a diary. The treatment with nebulized terbutaline combined with PEP gave the best relief in symptoms. All treatments increased PEF significantly. PEP alone gave the least increase in PEF (25 1/min), and there was no difference between the increase in PEF after terbutaline inhaled with PEP (28 1/min) compared to terbutaline alone (29 1/min).

Adult↗