Biomedical subjects

H Hedenström

Publications and source records attributed to H Hedenström.

At least 19 recordsLinked to original sources

PubMed2004

Pulmonary function after autologous bone marrow transplantation in children: a long-term prospective study.

We performed serial pulmonary function tests (PFTs) consisting of spirometry and diffusing capacity in 26 children after BMT. The median follow-up was 10 years. The influence of total body irradiation (TBI) on long-term pulmonary function was of particular interest. In the 20 children who had received TBI, after an initial decrease the PFTs showed recovery, but the mean lung volumes were still significantly decreased 5 years after BMT at 10% below baseline. The proportions of children with restrictive impairment 5 and 10 years after BMT were 20 and 21%, respectively. Only one child was diagnosed with obstructive impairment. The proportions of children with isolated diffusing impairment at 5 and 10 years were 7/20 (35%) and 7/13 (54%), respectively. Six children had received chemotherapy only and showed isolated diffusing impairment as the only long-term sequela in 4/5 and 1/3 at 5 and 10 years. Our main finding was that there was little change in PFTs 1-10 years after BMT. TBI was associated with persistently decreased lung volumes in a proportion of patients, whereas chemotherapy also might have been of importance for the development of impaired gas exchange.

Adolescent↗

PubMed2003

Delayed gastric emptying in patients with diffuse versus limited systemic sclerosis, unrelated to gastrointestinal symptoms and myoelectric gastric activity.

OBJECTIVE: To study the gastric function in patients with diffuse and limited systemic sclerosis (SSc) in relation to the degree of upper gastrointestinal symptoms. METHODS: Scintigraphic gastric emptying and recording of the myoelectric signals of the stomach were examined in 15 patients with diffuse SSc (dSSc), 13 patients with limited SSc (lSSc) and 15 healthy controls. The frequency of upper gastrointestinal symptoms was determined using a questionnaire. RESULTS: Patients with dSSc had slower gastric emptying (scintigraphic gastric half-emptying time median (Md) 103 min, range 75-447 min) than control subjects (Md 70 min, range 38-94) and patients with lSSc (Md 76 min, range 43-460). Electrogastrographic recordings did not differ between dSSc, lSSc or controls. Symptoms tended to be more abundant in dSSc patients than in lSSc patients, however, patients with a high frequency of symptoms did not differ from patients with low frequency of symptoms in gastric function, as measured with scintigraphic gastric emptying or electrogastrography (EGG). Neither EGG nor a thorough review of upper gastrointestinal symptoms could predict delayed gastric emptying. CONCLUSION: The higher prevalence of delayed gastric emptying in patients with dSSc in this study indicates a more severe involvement of the gastrointestinal tract in dSSc than in lSSc, and stresses the importance of differentiating between the subtypes of SSc patients. Since EGG dysrythmia did not correlate with gastric emptying we concluded that factors other than defective myoelectric signals might contribute to a disturbed gastric function.

Case-Control Studies↗

PubMed2002

Increased nitric oxide elimination from the airways after smoking cessation.

Smokers have been found to have low exhaled nitric oxide (NO) levels. The aim of the present study was to investigate where in the respiratory system the decrease in NO occurs, and whether this decrease was affected by smoking cessation. Measurements of exhaled NO were carried out in smokers (n=20) and non-smoking control subjects (n=30). In nine of the smokers, exhaled NO was analysed 1, 2 and 4 weeks after smoking cessation. The level of exhaled NO at a flow rate of 0.1 litre/s was significantly lower in smokers (4+/-2 p.p.b.) than in non-smokers (7+/-5 p.p.b.; P=0.007). A calculation of the contributions from different areas of the lung showed that the NO flux from the airways was significantly lower (14+/-10 compared with 36+/-26 nl/min; P=0.0001) and the alveolar fraction was significantly higher (2.1+/-0.8 compared with 1.5+/-0.9 p.p.b.; P=0.006) in smokers than in non-smokers. Nine smoking subjects refrained from smoking for 4 weeks, and this resulted in increased NO flux from the airways of 28+/-17 nl/min, which was no longer significantly different from controls. In conclusion, endogenous production of NO in the airways is decreased in smokers, but can be restored to normal values by 4 weeks after cessation of smoking. Smokers have an increased alveolar fraction of NO, and this might be a diagnostic sign of lung damage. Thus NO monitoring can be used to indicate improvements when a smoker decides to stop smoking.

Adult↗

PubMed2002

Extended NO analysis applied to patients with COPD, allergic asthma and allergic rhinitis.

The recommended method to measure exhaled nitric oxide (NO) cannot reveal the source of NO production. We applied a model based on the classical Fick's first law of diffusion to partition NO in the lungs. The aim was to develop a simple and robust solution algorithm with a data quality control feature, and apply it to patients with known alterations in exhaled NO. Subjects with allergic rhinitis, allergic asthma, chronic obstructive pulmonary disease (COPD) smokers and controls were investigated. NO was measured at three expiratory flow rates. An iteration method was developed to partition NO. The airway tissue content of NO was increased in asthma, 144 +/- 80 ppb (P = 0.04) and decreased in smokers, 56 +/- 36 ppb (P = 0.02). There was no difference between subjects with rhinitis, 98 +/- 40 ppb and controls, 98 +/- 44 ppb. The airway transfer rate was increased in allergic asthma and allergic rhinitis, 12 +/- 4 vs. 12 +/- 5 ml sec(-1), compared to controls, 8 +/- 2 ml sec(-1) (P < 0.001). The alveolar levels were no different from controls, 2 +/- 1 ppb. In COPD the alveolar levels were increased, 4 +/- 2 ppb (P < 0.001). Extended NO analysis reveals from where in the respiratory system NO is generated. Hence, this new test can be added to the tools the physician has for the diagnosis and treatment of patients with respiratory disorders.

Administration, Inhalation↗

PubMed2001

Inhaled mannitol shifts exhaled nitric oxide in opposite directions in asthmatics and healthy subjects.

We investigated if healthy subjects could release NO upon hyperosmolar challenge as a defence mechanism, and whether asthmatics with atopy showed an altered response. A plot of NO output versus flow rate was used to calculate the alveolar level and the NO-flux from the airways. The asthmatics had a higher NO output and this was due to an increased NO-flux from the airways, 86+/-30 nl min(-1) compared with control 21+/-2 nl min(-1) (P<0.05). The alveolar NO levels showed no difference. In response to a dry powder of mannitol the exhaled NO concentration decreased in asthmatics by 37+/-7%, but increased in the control by 9+/-4% (P<0.001). The FEV(1.0) decreased 13+/-2% and airway conductance 42+/-7% in asthmatics and in the controls 2+/-1% and 0+/-7%, respectively (P<0.001). We conclude that asthmatics have an altered response to mannitol challenge in regards to exhaled NO. This may result from down regulation of constitutive NO production as a result of high levels of NO flux from the airways.

Administration, Inhalation↗

PubMed2001

Investigation of the excluded stomach after Roux-en-Y gastric bypass.

BACKGROUND: One problem with Roux-en-Y gastric bypass (RYGBP) is that it leaves the bypassed segment not readily available for endoscopic or radiographic examinations. MATERIALS AND METHODS: Three males, 50, 54 and 64 years old, suffered from repeated, gastrointestinal bleeding of unknown origin requiring transfusion 1/2, 1 and 7 years after RYGBP. Access to the stomach was obtained by an ultrasound-guided percutaneous gastrostomy. RESULTS: We could perform endoscopy, barium studies and gastric acid output measurements through the gastrostomy. Histological gastritis, low acid output and absence of H. pylori infection were found. CONCLUSION: We were able to exclude severe gastric disease in our patients.

Acute Disease↗

PubMed2000

Different airway responsiveness profiles in atopic asthma, nonatopic asthma, and Sjögren's syndrome. BHR Study Group. Bronchial hyperresponsiveness.

BACKGROUND: Different mechanisms may underlie bronchial hyperresponsiveness (BHR) in different diseases. The aim of this study was to investigate the bronchial responsiveness profile produced by three different challenge tests, methacholine, a direct stimulus, and two indirect stimuli, adenosine 5'-monophosphate (AMP) and cold air, in subjects with asthma and patients with Sjögren's syndrome. METHODS: The study population comprised 40 adult patients with asthma, 18 subjects with Sjögren's syndrome, and 20 controls. Blood samples were collected before each challenge for measurements of serum eosinophil peroxidase (S-EPO) and eosinophil cationic protein (S-ECP). The investigated subjects recorded peak expiratory flow and kept a symptom diary. RESULTS: Atopic subjects with asthma were significantly more hyperresponsive to AMP than nonatopic subjects with asthma (P=0.01) and subjects with Sjögren's syndrome (P=0.02). No difference was seen between atopic and nonatopic subjects with asthma in the case of challenges with methacholine or cold air. In atopic subjects with asthma, a significant correlation was found between challenges with methacholine and AMP (r=0.91, P=0.0001) and methacholine and cold air (r=0.83, P=0.004), but, in nonatopic subjects with asthma, no significant correlation was seen between methacholine and AMP or cold air challenges. In atopic subjects with asthma, the dose-response slope for AMP was correlated to S-EPO (r= -0.56; P = 0.01) and S-ECP (r= -0.51, P = 0.02), while no correlation between BHR and inflammation markers was found in the two other patient groups. CONCLUSIONS: The results of this study suggest that patients with asthma and subjects with Sjögren's syndrome display different bronchial responsiveness profiles for different challenge agents. Atopic subjects with asthma are more hyperresponsive to AMP than nonatopic subjects and patients with Sjögren's syndrome. More than one challenge may be required to detect different aspects of bronchial responsiveness.

Adenosine Monophosphate↗

PubMed1999

Exhaled nitric oxide and its relationship to airway responsiveness and atopy in asthma. BHR-Study Group.

Exhaled nitric oxide (NO) has attracted increasing interest as a non-invasive marker of airway inflammation. The purpose of this study was to determine whether exhaled nitric oxide in subjects with asthma varied according to their atopic status and to examine its correlation with airway hyperresponsiveness and lung function measurements. Forty patients with asthma and 13 controls participated in the study. Nitric oxide was measured on three occasions with intervals of at least 3 days, using a chemiluminescence method. Airway responsiveness was assessed with methacholine challenge and lung function measurements were made. All subjects recorded peak expiratory flow and kept a symptom diary during a 17-day period. There was no significant difference in lung function measurements, peak expiratory flow or symptom score between the two asthma groups. Atopic patients with asthma had a significantly higher mean amount of exhaled NO than non-atopic subjects with asthma (162 +/- 68 vs. 113 +/- 55 nl min-1; P = 0.03) and the control group (88 +/- 52 nl min-1; P = 0.004). No significant difference was found in the amount of exhaled NO between non-atopic patients with asthma and the controls. In atopic subjects with asthma the mean exhaled NO was significantly correlated to the dose-response slope for methacholine (r = -0.52; P = 0.02), while no such correlation was found in the non-atopic group. In conclusion; in this study, atopic subjects with asthma had higher levels of exhaled NO than non-atopic subjects. Atopic status should be taken into account when measuring levels of exhaled NO in subjects with asthma.

Adolescent↗

PubMed1999

Increased nitric oxide in expired air in patients with Sjögren's syndrome. BHR study group. Bronchial hyperresponsiveness.

Nitric oxide has an important role in the regulation of airway function and can have pro-inflammatory effects. Bronchial hyperresponsiveness (BHR) and respiratory symptoms are common in patients with Sjögren's syndrome (SS). The aim of this study was to determine whether patients with SS have an increased amount of exhaled NO and whether this NO correlates with respiratory symptoms and BHR. Exhaled NO was measured in 18 patients with SS and 13 normal subjects on three different occasions with intervals of at least 3 days using a chemiluminescence method. Airway responsiveness was assessed with methacholine provocation. Serum levels of myeloperoxidase (MPO), human neutrophil lipocalin (HNL), eosinophil cationic protein (ECP) and eosinophil peroxidase (EPO) were measured. Exhaled NO was significantly higher in patients with SS than in controls (147+/-82 versus 88+/-52 nL x min(-1); mean+/-SD; p=0.041). Exhaled NO was correlated with age (partial r=0.52, p=0.006) and serum HNL (partial r=0.46, p=0.014). There were no significant correlations between exhaled NO and respiratory symptoms, BHR or serum MPO, ECP or EPO. Disease duration was negatively associated with serum MPO (r=-0.47, p=0.043). In patients with SS, a positive correlation was found between symptom score and serum ECP (partial r=0.65, p=0.003) and EPO (partial r=0.62, p=0.004) and a negative correlation with age (partial r=-0.60, p=0.005). In conclusion, elevated levels of exhaled nitric oxide in patients with Sjögren's syndrome were demonstrated. The mechanism underlying this increase in exhaled nitric oxide in Sjögren's syndrome is not known.

Breath Tests↗

PubMed1999

Comparison of two methacholine challenge methods using Spira-2 or Mefar dosimeter.

Two bronchial challenge protocols with breath-actuated dosimeters, Spira Elektro-2 and Mefar, with similar cumulative dose steps were compared in 28 patients with mild to moderate asthma. Methacholine challenges were performed after two different protocols at the same time of day in random order 3 or 4 days apart. The provocative dose of methacholine producing a 20% fall in forced expiratory volume in 1 second (PD20) was lower when determined by Spira than with the Mefar dosimeter (P < 0.05). Transition equations calculated by linear regression analysis were: PD20mefar = exp10[0.897 + 0.678(logPD20spira)] (P < 0.05; r = 0.62) and PD20spira = exp10[0.759 + 0.559 (log PD20mefar)] (P < 0.05; r = 0.62). The slopes were calculated by regressing the percentage fall in FEV1 on log10 (dose) and transformed as slope = 100/(regression coefficient + 10). The mean slope (95% CI) for Spira was 3.1 (2.6-3.7) and for Mefar 4.4 (3.6-5.1) (P < 0.005). Regression equations calculated by linear regression analysis were: slope(mefar) = 2.126 + 0.712 slope(spira) (P < 0.05; r = 0.51) and slope(spira) = 1.551 + 0.365 slope(mefar) (P < 0.05; r = 0.51). In conclusion, PD20 was smaller and the decline in FEV1/log(dose) curve steeper using the Spira compared with the Mefar protocol. The dose-response curves should be validated and transition equations calculated when bronchial reactivity to inhaled agents is compared, even while using apparently similar well-standardized dosimeter methods.

Adolescent↗

PubMed1999

Rapid effect of lansoprazole on intragastric pH: a crossover comparison with omeprazole.

BACKGROUND: The time to onset of acid inhibition is considered an important factor when treating patients with reflux symptoms. This study was therefore designed to investigate the effect of 30 mg lansoprazole and 20 mg omeprazole on gastric pH after single-dose administration. METHODS: The study was of a randomized, open-label, single-dose and two-way crossover design with a washout period of at least 7 days in between. Fifteen healthy adult male and female subjects were included. The subjects were intubated with a pH catheter. Intragastric pH was measured every 4th sec for 10 min before and during 8 h after drug administration. Blood samples, for determination of plasma concentrations of lansoprazole and omeprazole, were obtained on 10 occasions during 6 h after drug administration. The area under the curve (AUC), the elimination halflife (t1/2), and the peak concentration (Cmax) of the two drugs were calculated. RESULTS: All subjects completed the study without major complications. The mean pH (0-8 h) after drug administration was 2.9 for lansoprazole and 2.0 for omeprazole (P = 0.0058). A pH of more than 4 was reached for the first time after 130 min with lansoprazole and after 250 min with omeprazole. AUC was 4919 +/- 2526 nmol/l x h for lansoprazole and 1352 +/- 1120 nmol/l x h for omeprazole. CONCLUSION: Single-dose administration of 30 mg lansoprazole is followed by a rapid absorption of the drug and hence a more efficient acid suppression than after single-dose administration of 20 mg omeprazole in healthy volunteers.

2-Pyridinylmethylsulfinylbenzimidazoles↗

PubMed1999

Ozone-induced lung function decrements do not correlate with early airway inflammatory or antioxidant responses.

This study sought to clarify the early events occurring within the airways of healthy human subjects performing moderate intermittent exercise following ozone challenge. Thirteen healthy nonsmoking subjects were exposed in a single blinded, crossover control fashion to 0.2 parts per million (ppm) O3 and filtered air for 2 h, using a standard intermittent exercise and rest protocol. Lung function was assessed pre- and immediately post-exposure. Bronchoscopy was performed with endobronchial mucosal biopsies, bronchial wash (BW) and bronchoalveolar lavage (BAL) 1.5 h after the end of the exposure period. Respiratory tract lining fluid (RTLF) redox status was assessed by measuring a range of antioxidants and oxidative damage markers in BW and BAL fluid samples. There was a significant upregulation after O3 exposure in the expression of vascular endothelial P-selectin (p<0.005) and intercellular adhesion molecule-1 (p<0.005). This was associated with a 2-fold increase in submucosal mast cells (p<0.005) in biopsy samples, without evidence of neutrophilic inflammation, and a decrease in BAL fluid macrophage numbers (1.6-fold, p<0.005), with an activation of the remaining macrophage subset (2.5-fold increase in % human leukocyte antigen (HLA)-DR+ cells, p<0.005). In addition, exposure led to a 4.5-fold and 3.1-fold increase of reduced glutathione (GSH) concentrations, in BW and BAL fluid respectively (p<0.05), with alterations in urate and alpha-tocopherol plasma/RTLF partitioning ratios (p<0.05). Spirometry showed reductions in forced vital capacity (p<0.05) and forced expiratory volume in one second (p<0.01), with evidence of small airway narrowing using forced expiratory flow values (p<0.005). Evidence was found of O3-induced early adhesion molecule upregulation, increased submucosal mast cell numbers and alterations to the respiratory tract lining fluid redox status. No clear relationship was demonstrable between changes in these early markers and the lung function decrements observed. The results therefore indicate that the initial lung function decrements are not predictive of, or causally related to the O3-induced inflammatory events in normal human subjects.

Adult↗

PubMed1997

Lung density for assessment of hydration status in hemodialysis patients using the computed tomographic densitometry technique.

The density of the lung reflects the total mass of fluid, air, and dry lung tissue per unit volume of the lung. Lung density can be measured by evaluation of attenuation of an electron beam with computed tomography (CT). This technique has been shown to be sufficiently reliable and sensitive to distinguish normal from abnormal lung water. The aim of this study was to find out whether lung density properly reflects the hydration status in hemodialysis patients in comparison with other standard methods. Fourteen hemodialysis patients, with an ultrafiltration ranging from 0.3 to 4.5 liters per session, underwent CT measurements of lung density, ultrasonographic measurements of the diameter of the inferior vena cava after quiet expiration (IVCe) and quiet inspiration (IVCi), and measurements of the hematocrit and plasma levels of the biochemical hydration markers cyclic guanosine monophosphate (cGMP) and atrial natriuretic peptide (ANP). These measurements were performed before and 3.5 to 4 hours after termination of dialysis. Quantitative estimates of lung density were obtained within pixels with CT numbers ranging between -1000 and -100 Hounsfield Units (HU), and compared with normal data from 18 normal controls. In normal controls, the lung density ranged from -800 to -730 HU. In hemodialysis patients, lung density was significantly higher than normal before dialysis (-678 +/- 96 HU, P < 0.01) and significantly decreased after dialysis (-706 +/- 92 HU, P < 0.05), indicating a decrease in fluid content of the lung. The density was normalized in 5 patients. A significant correlation was found between lung density and IVCe both before and after dialysis (r = 0.8, P < 0.01 for both). Change in density was significantly correlated to amount of ultrafiltration (r = 0.67, P < 0.01) and percent change in blood volume (r = 0.63, P < 0.05), indicating that lung density is greatly affected by changes in the extracellular fluid volume, mainly the intravascular volume. In conclusion, lung water reflects the hydration status in hemodialysis patients and can be monitored by measuring the lung density by CT. Accordingly, normalization of lung density can help to achieve a proper dry weight in these patients.

Adult↗

PubMed1997

Intragastric pH after oral administration of single doses of ranitidine effervescent tablets, omeprazole capsules and famotidine fast-dissolving tablets to fasting healthy volunteers.

BACKGROUND: The therapeutic effect of drugs inhibiting acid production on acid-related discomforts is related to both the onset and duration of action of the drug. The effects on gastric pH by single oral doses of some acid-inhibiting drugs were investigated by measuring daytime (morning to lunch) intragastric pH in healthy volunteers. METHODS: This randomized, single-dose, 4-way crossover study included 15 healthy fasting subjects. Effervescent ranitidine tablets 150 and 300 mg, fast-dissolving famotidine tablets 20 mg and capsules of omeprazole 20 mg were administered. Measurements of intragastric pH were performed every 4 s for 10 min prior to drug administration and during the following 4 h. RESULTS: The effervescent ranitidine tablets (150 or 300 mg) produced similar changes in intragastric pH: following an immediate increase to about pH 5, intragastric pH decreased slightly over the next 10-20 min. Thereafter pH increased steadily, reaching pH 4 after 20-40 min and pH 6 after about 70 min. After famotidine, pH 4 was reached after 80 min, significantly slower than ranitidine. After omeprazole, pH 3 was never reached. Ranitidine 150 and 300 mg showed significantly larger integrated pH responses over the 4-h observation period, compared to famotidine (P = 0.0288 and 0.0074) or omeprazole (P < 0.001). CONCLUSIONS: After single-dose administration to healthy fasting volunteers), ranitidine effervescent tablets showed a significantly more rapid onset of action and a significantly larger integrated pH response compared to either famotidine 20 mg fast-dissolving tablets or omeprazole 20 mg capsules.

Administration, Oral↗

PubMed1997

Computed tomographic measurement of lung density changes in lung water with hemodialysis.

In 10 hemodialysis patients, with an ultrafiltration volume ranging from 1 to 4.5 liters per session, the lung density was measured by computed tomography (CT) and the lung volumes by total body plethysmography. From the CT numbers (difference in X-ray attenuation between lung and water, measured in Hounsfield units, HU), and by using a special computer program, quantitative estimates of the densities of normally inflated (pixels between -1,000 and -500 HU), poorly inflated (pixels between -500 and -100 HU) and noninflated lung tissue (pixels between -100 and +100 HU) were obtained. The sizes of the normally and poorly inflated areas were also measured. The results showed that, after dialysis, the normally inflated area was decreased in density and increased in size, and conversely, the size of the poorly inflated area was diminished but without change in density. This finding implied introduction of more gas into the lung. The above observation was reflected by the results of pulmonary function measurements, in that the total lung capacity and functional residual capacity were significantly increased after dialysis. In conclusion, changes in lung fluid (both intra- and extravascular) with hemodialysis can be measured quantitatively by the changes in lung density as estimated by the CT densitometry technique.

Adult↗

PubMed1995

Large emphysematous bullae. Successful treatment with thoracoscopic technique using fibrin glue in poor-risk patients.

Five patients with poor lung function (FEV1, 0.8 to 1.0 L; MVV, 27 to 36 L/min) and large emphysematous bullae were operated on. Fibrin glue was introduced into the bullae through a thoracoscope. The results have been excellent and no serious perioperative or postoperative complications have occurred. The patients have all improved clinically and are very satisfied with the results. Postoperatively, FEV1 was between 1.0 and 1.2, and MVV was 30 to 52 L. The clinical improvement was, however, larger than these figures illustrate. Our preliminary experience using this technique suggests that it can be used in patients with very low lung function with a minimal risk. We propose that all patients with severe emphysema should be screened for bullous components because improvement might be possible by operation with this minimally traumatizing technique.

Aged↗

PubMed1994

The bronchial response, but not the pulmonary response to inhaled methacholine is dependent on the aerosol deposition pattern.

The clinical effect of inhaled radio-labeled (Technetium-99m diethylenetriamine-pentaacetic acid) methacholine was studied in two separate experiments performed in eight symptom-free asthmatics with bronchial hyperresponsiveness. Aerosols were formed by two different nebulizers, producing either mainly small aerosol particles (2-microns mass median aerodynamic diameter [MMAD]) for peripheral, or mainly large aerosol particles (9-microns MMAD) for large airway deposition. The intended site of deposition was confirmed by gamma camera recordings. Changes in specific airway conductance (sGaw) were set as an index of central airway constriction, and functional alterations in the gas exchanging parts of the lung were estimated by multiple inert gas elimination technique (MIGET) and arterial blood gas analyses. The main finding was that the responses, as measured by the changes in arterial blood gases and by MIGET, were similar in the two experiments, while the fall in sGaw was significantly larger after deposition in the main bronchi than in the peripheral airways (p < 0.05). The time courses of the abnormalities in the gas exchanging elements were much longer than those of the responses of the central airways, and the abnormalities were recorded still at the end of the experiment 2 h after challenge in most patients. A discrepancy in dose dependency and time courses suggests differences in mechanism and/or dynamics of the responses exerted by the various target organs. Interaction in the process of clearance from the lung of inhaled methacholine by the bronchial circulation may have contributed to the observed discrepancies.

Adult↗

PubMed1993

Changes in lung function of granite crushers exposed to moderately high silica concentrations: a 12 year follow up.

45 granite crushers and 45 age and smoking matched referents underwent pulmonary function tests in 1976 and 1988. On average, the granite crushers at follow up had worked for 22 years, were 52 (range 36-78) years old, and had inhaled a cumulated amount of 7 mg of silica in the respirable dust fraction. Between 1976 and 1988 the average concentration of respirable quartz in air was 0.16 mg/m3 (threshold limit value (TLV) = 0.10 mg/m3). In 1988 the granite crushers had somewhat lower forced expiratory flows (forced expiratory volume in one second/vital capacity (FEV1/VC) -4.5% and forced midexpiratory flow FEF50 -15%) compared with the referents and a more uneven ventilation distribution (17% higher slope of phase III in the nitrogen single breath curve). Five smoking granite crushers, but none of the referents, had an FEV1 < 80% of the predicted. During the 12 year interval the granite crushers had--compared with the matched referents--a greater decrease in FEV1 (-4.6%), FEV1/VC (-5.4%), maximal expiratory flow, (-8%) and FEF50 (-14%), and a larger increase in phase III and static compliance (p < 0.02 in all variables). The functional changes suggest the presence of airways obstruction and increased compliance of the lungs. Exposure to silica at concentrations of about twice the present TLV was thus associated with airways obstruction and loss of elastic recoil rather than fibrosis and a restrictive function loss as seen in silicosis. The changes were on average small, but in some tobacco smokers more pronounced changes were found.

Adult↗