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Biomedical subjects

T Sandström

Publications and source records attributed to T Sandström.

At least 73 records · Page 4Linked to original sources
PubMed1996

Effects on symptoms and lung function in humans experimentally exposed to diesel exhaust.

OBJECTIVES: Diesel exhaust is a common air pollutant made up of several gases, hydrocarbons, and particles. An experimental study was carried out which was designed to evaluate if a particle trap on the tail pipe of an idling diesel engine would reduce effects on symptoms and lung function caused by the diesel exhaust, compared with exposure to unfiltered exhaust. METHODS: Twelve healthy non-smoking volunteers (aged 20-37) were investigated in an exposure chamber for one hour during light work on a bicycle ergometer at 75 W. Each subject underwent three separate double blind exposures in a randomised sequence: to air and to diesel exhaust with the particle trap at the tail pipe and to unfiltered diesel exhaust. Symptoms were recorded according to the Borg scale before, every 10 minutes during, and 30 minutes after the exposure. Lung function was measured with a computerised whole body plethysmograph. RESULTS: The ceramic wall flow particle trap reduced the number of particles by 46%, whereas other compounds were relatively constant. It was shown that the most prominent symptoms during exposure to diesel exhaust were irritation of the eyes and nose and an unpleasant smell increasing during exposure. Both airway resistance (R(aw)) and specific airway resistance (SR(aw)) increased significantly during the exposures to diesel exhaust. Despite the 46% reduction in particle numbers by the trap effects on symptoms and lung function were not significantly attenuated. CONCLUSION: Exposure to diesel exhaust caused symptoms and bronchoconstriction which were not significantly reduced by a particle trap.

Adult↗
PubMed1996

Skeletal muscle magnesium and potassium in asthmatics treated with oral beta 2-agonists.

Dietary magnesium has been shown to be important for lung function and bronchial reactivity. Interest in electrolytes in asthma has so far mainly been focused upon serum potassium, especially linked to beta 2-agonist treatment. It is known that serum levels of magnesium and potassium may not correctly reflect the intracellular status. We therefore investigated whether asthmatics treated with oral beta 2-agonists had low magnesium or potassium in skeletal muscle and serum, and whether withdrawal of the oral beta 2-agonists would improve the electrolyte levels. Magnesium and potassium levels in skeletal muscle biopsies, serum and urine were analysed in 20 asthmatics before and 2 months after withdrawal of long-term oral beta 2-agonists, and for comparison in 10 healthy subjects. Skeletal muscle magnesium in the asthmatics was lower both before (3.62 +/- 0.69 mmol.100 g-1 (mean +/- SD)) and after (3.43 +/- 0.60 mmol.100 g-1) withdrawal of oral beta 2-agonists compared with the controls (4.43 +/- 0.74 mmol.100 g-1). Skeletal muscle potassium and serum magnesium did not differ between the groups. Serum potassium was significantly lower both before (4.0 +/- 0.2 mmol.L-1) and after (3.9 +/- 0.2 mmol.L-1) the withdrawal of oral beta 2-agonists compared with the control group (4.2 +/- 0.2 mmol.L-1). The asthmatics had lower skeletal muscle magnesium and lower serum potassium than the healthy controls, both with and without oral beta 2-agonists. Whether the findings are related to asthma pathophysiology or treatment is currently being investigated.

Administration, Oral↗
PubMed1995

Experimental evaluation of the effect of filtration of diesel exhaust by biologic exposure indicators.

The airway resistance, compliance of the respiratory system, transfer factor, and alveolar volume of 33 healthy rabbits were studied before and after exposure to diluted diesel exhaust generated in an experimental motor. Three diesel fuels and two particle traps were tested. Subsequent to the post-exposure lung function measurements, the animals were sacrificed and the lungs were processed for morphologic examination. The concentrations of particles, nitrogen dioxide, and formaldehyde were measured. The inflammatory airway changes were most pronounced in animals exposed to exhaust from standard fuel. Small changes were identified in animals exposed to exhaust filtered through the catalytic trap as well or exposed to unfiltered exhaust from fuels intended for densely built-up areas. Increase in compliance of the respiratory system was associated with the concentration of soot particles and formaldehyde. Compliance decreased significantly in animals exposed to exhaust from standard fuel filtered through the particle traps and increased almost significantly in animals exposed to unfiltered exhaust from the same fuel.

Air Pollutants↗
PubMed1995

Effects of intrapleural mitoxantrone and mepacrine on malignant pleural effusion--a randomised study.

30 patients with malignant pleuritis were randomised to be treated, either with intrapleural instillation of mepacrine chloride or with mitoxantrone. The patients were evaluated with chest X-ray and a symptom questionnaire during a follow-up period of 12 weeks. Mitoxantrone levels in the pleural space and plasma were measured at different time points in some of the patients. High concentrations of mitoxantrone were found in the pleural fluid while the plasma concentrations were low, giving a plasma/intracavity ratio generally of less than 1:60. The chest X-rays showed excellent results for both treatment modalities. However, the patients treated with mepacrine chloride experienced greater discomfort with fever and pain, and those treated with mitoxantrone reported significantly less dyspnoea and less asthenia after 4 weeks. We conclude that both treatments are equally effective in preventing the recurrence of malignant effusion. However, mitoxantrone seems to have further advantages when it comes to improving the quality of life.

Adult↗
PubMed1995

Nitrogen dioxide exposure impairs the frequency of the mucociliary activity in healthy subjects.

In previous studies, we have reported bronchoalveolar lavage (BAL) findings following single and repeated exposures to NO2. Here, we present the first data on measurements of the frequency of the mucociliary activity in healthy subjects following exposure to NO2. Twenty four healthy nonsmoking volunteers underwent fibreoptic bronchoscopy, during which mucociliary activity was measured using an in vivo method based on a two-way fibreoptic system, to obtain baseline data. Two weeks later, the subjects were reinvestigated following NO2 exposure. Eight volunteers were investigated 45 min after a 20 min exposure to 1.5 ppm NO2 (Group A); eight subjects 45 min after a 20 min exposure to 3.5 ppm NO2 (Group B); and eight subjects 24 h after a 4 h exposure to 3.5 ppm NO2 (Group C). No activity was detected in Group A or B 45 min after exposure, in contrast to the easily identifiable mucociliary activity waves at the reference bronchoscopy. In group C, a significant elevation of the frequency of the mucociliary activity waves was seen at 24 h. It is concluded that short-term exposure to NO2 in man produces a significant reduction in the mucociliary activity 45 min after exposure. The effect ceases within 24 h. Further studies are needed to evaluate the effects of repeated exposures with NO2 on mucociliary activity in man.

Adult↗
PubMed1995

Respiratory effects of air pollutants: experimental studies in humans.

Epidemiological and environmental chamber studies in man, and toxicological studies in animals, have provided valuable insights into the biological effects, the mechanisms of action, and the dose-response characteristics of some major air pollutants. This review describes the information currently available on air pollutant effects in man, as the result of experimental studies. There are certain advantages, as well as some limitations, in human chamber exposure studies, but if carefully designed and based upon relevant background data they may give information that is valuable for understanding the effects of air pollutants in man. Reversible effects on the airway mechanics, the responsiveness of the airways to methacholine and allergen have been shown to be caused by air pollutants. Furthermore, significant changes have been demonstrated in airway permeability, bronchoalveolar lavage, nasal lavage, and peripheral blood cells and inflammatory markers. Currently, human toxicology to air pollutants is a progressive research area.

Air Pollutants↗
PubMed1994

Sephadex-induced granulomatous alveolitis in rat: effects of antigen manipulation.

A granulomatous alveolitis, with multinuclear cell formation combined with an eosinophilic peribronchiolitis, was achieved in rats by intratracheal administration of sephadex beads (G-200, Pharmacia, Sweden). The pattern of inflammation and the degree of postgranulomatous fibrosis were substantially dampened when the particles were dispersed by ultrasonification. The animals were analyzed with bronchoalveolar lavage and tissue morphology.

Animals↗
PubMed1994

Evaluation of an exposure setup for studying effects of diesel exhaust in humans.

Diesel exhaust is a common air pollutant and work exposure has been reported to cause discomfort and affect lung function. The aim of this study was to develop an experimental setup which would allow investigation of acute effects on symptoms and lung function in humans exposed to diluted diesel exhaust. Diluted diesel exhaust was fed from an idling lorry through heated tubes into an exposure chamber. During evaluations of the setup we found the size and the shape of the exhaust particles to appear unchanged during the transport from the tail pipe to the exposure chamber. The composition of the diesel exhaust expressed as the ratios CO/NO, total hydrocarbons/NO, particles/NO, NO2/NO, and formaldehyde/NO were almost constant at different dilutions. The concentrations of NO2 and particles in the exposure chamber showed no obvious gradients. New steady state concentrations in the exposure chamber were obtained within 5-7 min. In a separate experiment eight healthy nonsmoking subjects were exposed to diluted exhaust at a median steady state concentration of 1.6 ppm NO2 for the duration of 1 h in the exposure chamber. All subjects experienced unpleasant smell, eye irritation, and nasal irritation. Throat irritation, headache, dizziness, nausea, tiredness, and coughing were experienced by some subjects. Lung function was not found to be affected during the exposure. The experimental setup was found to be appropriate for creating different predetermined steady state concentrations in the exposure chamber of diluted exhaust from a continuously idling vehicle. The acute symptoms reported by the subjects were relatively similar to what patients reported at different workplaces.

Adult↗
PubMed1994

Differences in bronchoalveolar cell response to nitrogen dioxide exposure between smokers and nonsmokers.

We have previously reported on the bronchoalveolar inflammatory effects of the common air pollutant NO2 in nonsmokers. In this study, we have investigated these effects in tobacco smokers. Eight young nonbronchitic smokers and, as a reference group, eight healthy life-time nonsmokers were exposed to 3.5 ppm NO2 for 20 min. Bronchoalveolar lavage (BAL) was performed 3 weeks before and 24 h after exposure. The first recovered 20 ml was analysed separately and defined as the bronchial portion (BP), and the following fluid recovered as the bronchoalveolar portion (BAP). Before exposure, the smokers had significantly less CD3+ cells and more alveolar macrophages (AMs) in the BP and the BAP, as well as reduced AM phagocytosis in vitro compared to nonsmokers. After NO2 exposure, the smokers reacted with an increase of AMs and neutrophils in BAP. Nonsmokers reacted with an increase of neutrophils in BP, an increase of lymphocytes in BAP, and a tendency to reduced AM phagocytosis. In summary, young smokers and nonsmokers differed to some extent in their reactions to NO2 exposure. This is probably due to the pre-existing airway inflammation and compensatory mechanisms to oxidant stress in the smokers.

Adult↗
PubMed1993

Time course and duration of bronchodilatation with formoterol dry powder in patients with stable asthma.

BACKGROUND: Formoterol, a new beta 2 agonist, is long and fast acting when given as an aerosol. The aim was to determine the onset and duration of bronchodilatation with formoterol as a dry powder compared with salbutamol dry powder and with placebo. METHODS: Fifteen patients with stable asthma with a reversibility of 15% or more participated in a double blind, within patient study. On five different days the patients received formoterol 6 micrograms, 12 micrograms, or 24 micrograms, salbutamol 400 micrograms, or placebo in random order. Forced expiratory volume in one second (FEV1) was measured 10 minutes before, 30 minutes after, and then every hour for up to 12 hours after treatment. Specific airway resistance (sRaw) and specific airway conductance (sGaw) were measured immediately before and one, three, five, 10, 15, and 30 minutes after treatment. RESULTS: Formoterol 12 micrograms and 24 micrograms caused bronchodilatation as rapidly as salbutamol 400 micrograms. Peak values were not significantly different in the active treatments. The duration of action, calculated as median time with 20% or more of the maximum achieved increase in FEV1, was sustained for 9 hours and 16 minutes with salbutamol 400 micrograms, for 9 hours and 45 minutes with formoterol 6 micrograms, for 11 hours and 22 minutes with formoterol 12 micrograms, and for 11 hours and 42 minutes with formoterol 24 micrograms. CONCLUSIONS: Formoterol as a dry powder at doses of 12 micrograms and 24 micrograms produces a rapid onset of action and has a bronchodilator effect comparable with salbutamol 400 micrograms as a dry powder. The bronchodilatation was sustained for 11-12 hours. Formoterol 6 micrograms caused similar bronchodilatation but more slowly and for a shorter time.

Administration, Inhalation↗
PubMed1993

Local host response in the lower respiratory tract in nephropathia epidemica.

Various lines of evidence suggest a respiratory route of transmission of nephropathia epidemica (NE). To study the response of the respiratory tract in NE, fiberoptic bronchoscopy with bronchoalveolar lavage (BAL) was performed in 5 patients in the acute phase of the disease. Compared to a reference group of 15 healthy individuals, BAL fluid of NE patients contained significantly higher total numbers of cells (p < 0.05) and significantly higher numbers of lysozyme-positive macrophages (p < 0.01), CD8+ T cells (p < 0.01), and natural killer (NK) cells (p < 0.01). There was no significant difference in numbers of CD4+ T cells, B cells, or neutrophils. When blood samples of 16 patients were examined at various intervals after onset of NE, a significant decrease in the number of NK cells (p < 0.01) was found in the acute phase of the disease. The findings are compatible with the presence of a local host response in the lower respiratory tract to NE virus infection.

Acute-Phase Reaction↗
PubMed1992

Reductions in lymphocyte subpopulations after repeated exposure to 1.5 ppm nitrogen dioxide.

In this investigation the effects of repeated exposure to 1.5 ppm NO2 on immune competent cells in bronchoalveolar lavage (BAL) fluid was studied. Special attention was focused on effects on lymphocyte subpopulations. Eight healthy subjects were exposed to 1.5 ppm NO2 every second day on six occasions. Bronchoalveolar lavage fluid was collected at least three weeks before the exposure series as reference and 24 hours after the last exposure. The results obtained were analysed using a non-parametric test for paired observations, with each subject as his own control. Significant reductions were found in the total number and percentage of T cytotoxic-suppressor cells in BAL fluid; this caused an increase in the ratio of T helper-inducer: cytotoxic-suppressor cells. The total number of natural killer cells in the BAL fluid was also reduced. The numbers of all other cell types were unchanged after exposure. No reduction of phagocytosis of opsonised yeast particles by alveolar macrophages in vitro was detected. It is concluded that repeated short term exposures to 1.5 ppm NO2, a moderate occupational concentration, induces significant effects on immune competent bronchoalveolar lymphocytes. This indicates that previous findings of changes in the lymphoid immune system induced by NO2 in animals may well be applicable to humans.

Adult↗
PubMed1992

Lipopolysaccharide (LPS) inhalation in healthy subjects increases neutrophils, lymphocytes and fibronectin levels in bronchoalveolar lavage fluid.

Bacterial endotoxin has been suggested as responsible for the development of subjective symptoms and transient or chronic lung function impairment seen after exposure to organic dusts in cotton mills, poultry houses, swine confinement buildings and saw mills. Animal experiments have demonstrated bronchoalveolar neutrophilia being the most prominent cell response in animals following bacterial lipopolysaccharide (LPS) inhalation. The present study was conducted to obtain information on some aspects of the early inflammatory response to inhaled LPS in man. Eight healthy nonsmoking subjects, 23-27 yrs old, underwent bronchoalveolar lavage (BAL), 3 h after a provocation test with 100 micrograms LPS from E. coli dissolved in 2 ml isotonic NaCl. The solution was aerosolized with a jet nebulizer and inhaled. The calculated dose delivered to the lung was approximately 25 micrograms, which equals exposure in some occupational settings. The BAL data for each individual subject were compared with data from a control BAL performed at least 6 weeks prior to the LPS challenge. The major cellular response to LPS, reflected in BAL fluid, was an approximately hundredfold increase in neutrophils. The total number of lymphocytes was on average tripled. The alveolar macrophage phagocytosis of opsonized yeast particles in vitro was significantly reduced. A further indicator of an ongoing inflammation was an increase in fibronectin. No changes were seen in the levels of BAL albumin, indicating that the elevated level of fibronectin could not be explained by an increased permeability, but rather by a local production. The results correspond with data from animal studies and further supports the hypothesis that bacterial LPS is important in the pulmonary reaction induced by organic dusts.

Administration, Inhalation↗
PubMed1992

Effects of repeated exposure to 4 ppm nitrogen dioxide on bronchoalveolar lymphocyte subsets and macrophages in healthy men.

Following the basal descriptive studies of the bronchoalveolar inflammatory cell response induced by single exposure with nitrogen dioxide (NO2) in man, it was considered important to clarify the cell response to repeated exposure with NO2. This investigation was, therefore, undertaken with bronchoalveolar lavage (BAL) 3 weeks before and 24 h after six repeated exposures with 4 ppm NO2 (7 mg.m-3) in ten healthy volunteers. The exposures were performed during 20 min and every second day. Analysis of the recovered BAL fluid demonstrated that repeated exposures to NO2 caused a lung cell response different from that reported after a single exposure. Amounts of lavaged alveolar macrophages, B-cells, and natural killer (NK)-cells were decreased and the T-helper-inducer/cytotoxic-suppressor cell ratio was altered, but there was no lymphocytosis or mastocytosis as after single exposure. Lymphocyte numbers in peripheral blood were reduced after exposure. These results suggest that repeated exposure with NO2 adversely affects the immune defence. This could contribute to the increased susceptibility to airway infections reported to be associated with NO2 exposure.

Adult↗
PubMed1992

Radiation-induced increase in hyaluronan and fibronectin in bronchoalveolar lavage fluid from breast cancer patients is suppressed by smoking.

Bronchoalveolar lavage (BAL) fluid was analysed from 21 patients with breast cancer, stage T1N0M0, who had undergone tumour resection and post-operative local irradiation (accumulated dose 56 Gy). The lavage was performed two months after radiotherapy, in the anterior part of the lingula (left side) or of the right middle lobe (right side), depending on which side had been exposed to radiation. The patients had significantly increased concentrations of fibronectin (FN) (p less than 0.001), hyaluronan (HA) (p less than 0.01) and albumin (p less than 0.05) in BAL fluid compared with the healthy controls (n = 19). However, when the patients were separated, according to smoking history, it was obvious that the inflammatory reaction occurred entirely in the nonsmoking patient group (n = 10), whilst no difference could be found between the smoking patients (n = 11) and the controls. In the nonsmoking patient group, there was a sevenfold increase in BAL concentrations of FN and a threefold increase in HA. Moreover, four patients had detectable levels of procollagen III peptide in BAL, all were nonsmokers. The smoking habits of the controls had no influence on the BAL measurements. These findings indicate that smoking interferes with the radiation-induced early inflammatory connective tissue reaction of the lung. Finally, the results justify further investigation of interaction of smoking with cancer treatment, both from the view of therapy effectiveness and reduction of adverse effects.

Albumins↗
PubMed1991

Efficacy of enprofylline in acute airway obstruction.

The efficacy and safety of different regimens of intravenously administered enprofylline, an anti-asthma xanthine, were evaluated in a randomized open study, including 155 patients with acute exacerbation of obstructive lung disease. The regimen 2.5 mg/kg i.v. over 10 min was canceled after seven patients had been included, due to two cases of hypotensive/vasovagal reactions. The regimens 2.0 mg/kg/20 min and 2.5 mg/kg/20 min were significantly more effective with regard to bronchodilation than 2.0 mg/kg/10 min (PEF increase +35%, +30% and +17% respectively). Nausea and headache were the most common side effects (16-33% and 23-33% of the patients respectively on different regimens) with the lowest frequency on 2.0 mg/kg/20 min. Four additional hypotensive reactions occurred; one on each 2.0 mg/kg regimen and two on 2.5 mg/kg/20 min. The regimen 2.0 mg/kg20 min was found to be the most favourable with regard to efficacy and side effects. Enprofylline i.v. was found to be an effective bronchodilating treatment of acute airway obstruction but the frequency of side effects has to be considered.

Acute Disease↗
PubMed1991

Exposure to peat dust: acute effects on lung function and content of bronchoalveolar lavage fluid.

Mechanised production of peat for fuel consumption is associated with high concentrations of organic dust, which is inhaled by the peat workers. In the present study 17 workers at two peat bogs in northern Sweden were examined. Personal sampling of total dust and the respirable fraction was performed during several workshifts. Dynamic spirometry was carried out before and at the end of shifts. Bronchoscopy with bronchoalveolar lavage (BAL) was performed in six subjects at the end of the working season and the results were compared with unexposed reference subjects. Peat workers using modern machines with ventilated cabins containing air filters were found to be exposed to low concentrations of peat dust. The recorded dust concentrations were below the threshold limit value for organic dust (5 mg/m3 air) in all but one worker. The respirable fraction of peat dust recorded in the breathing zone of the workers correlated significantly with a decrease in forced expiratory volume in one second (FEV1). The effect on lung function in non-asthmatic peat workers was, however, small. The concentration of lysozyme positive alveolar macrophages in BAL fluid was significantly lower in the peat workers compared with reference subjects. An inverse correlation was found between the mentioned cells and exposure to the respirable fraction of the peat dust. Furthermore, one particularly dust exposed worker had pronounced increases in alveolar macrophages, fibronectin concentration, and mast cells in BAL fluid.

Adolescent↗