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Biomedical subjects

J H Dijkman

Publications and source records attributed to J H Dijkman.

At least 19 recordsLinked to original sources

Long-term effects of a long-acting beta 2-adrenoceptor agonist, salmeterol, on airway hyperresponsiveness in patients with mild asthma.

BACKGROUND: Asthma is characterized by hyperresponsiveness of the airways to bronchoconstrictive stimuli. Long-acting beta 2-adrenoceptor agonists have been introduced as a new therapeutic approach, but there is growing concern about whether control of asthma may deteriorate with the regular use of these agents. We investigated the long-term effects of the beta 2 agonist salmeterol on bronchodilation and on airway hyperresponsiveness to the bronchoconstrictive agent methacholine in mild asthma. METHODS: In a parallel, double-blind study, 24 patients with mild asthma were randomly assigned to treatment with either inhaled salmeterol (50 micrograms, twice daily) (n = 12) or placebo (n = 12) during an eight-week trial. Methacholine challenge was performed before, during, and after the treatment period. Methacholine responsiveness was measured as the provocative concentration (PC20) that caused a 20 percent decrease in the forced expiratory volume in one second (FEV1). RESULTS: There was a significant increase in FEV1 one hour after the inhalation of salmeterol (P = 0.006), which did not differ significantly on days 0, 28, and 56 of the treatment period (increase, 9.8, 9.4, and 8.8 percent of predicted FEV1, respectively; P = 0.91). On the first treatment day, salmeterol afforded significant protection against methacholine-induced bronchoconstriction, as shown by a 10-fold increase in the PC20 as compared with the value at entry (P less than 0.001). After four and eight weeks of treatment, however, the salmeterol-induced change in the PC20 was significantly attenuated (P less than 0.001) to only a twofold increase. Two and four days after treatment ended, the PC20 was not significantly different from the value before treatment (P = 0.15). CONCLUSIONS: Regular treatment of patients with mild asthma with salmeterol leads to tolerance to its protective effects against a bronchoconstrictor stimulus, in this case inhaled methacholine, despite well-maintained bronchodilation. This finding raises concern about the effectiveness of prolonged therapy with long-acting beta 2-adrenoceptor agonists in asthma.

Adrenergic beta-Agonists

Induction of emphysema and bronchial mucus cell hyperplasia by intratracheal instillation of lipopolysaccharide in the hamster.

The aim of this study was to determine whether lipopolysaccharide-induced elastase release from recruited neutrophils in the hamster lung would induce emphysema, measured by mean linear intercept (Lm) and bronchial mucus cell hyperplasia (BMCH), scored in tissue sections stained with periodic acid-Schiff. Lipopolysaccharide (LPS) was instilled transorally twice a week for up to 5 weeks in hamsters. At 4 weeks after seven LPS instillations, Lm amounted to 87.6 +/- 1.2 microns, while it was 68.3 +/- 1.5 microns after seven saline instillations (P less than 0.01). At 6 months after the sixth LPS instillation, the Lm of these lungs was 83.3 +/- 1.6 microns, indicating irreversible tissue destruction. LPS-treated hamsters showed marked to severe BMCH, which was most evident in large intrapulmonary airways. Instillations of highly selective inhibitor of hamster PMN elastase resulted in 50 per cent inhibition of LPS-induced emphysema. The development of BMCH was inhibited by approximately 35 per cent by this agent. To study the response in time of cellular infiltration after a single LPS instillation, the lungs of groups of four hamsters were lavaged at different time points. PMN recruitment showed peak values at 4 and 48 h after LPS instillation and returned to baseline values at 96 h. Simultaneous intratracheal instillation of LPS and anti-TNF alpha antiserum resulted in a considerable reduction of neutrophil influx into bronchoalveolar spaces in the first 6 h after instillation.

Animals

The long-term effect of nedocromil sodium on the maximal degree of airway narrowing to methacholine in atopic asthmatic subjects.

Airway hyperresponsiveness in asthma is characterized by increased airway sensitivity and by excessive maximal airway narrowing. Long-term inhalation therapy with nedocromil sodium has been shown to reduce increased airway sensitivity in asthma. However, it is unknown whether it also attenuates excessive airway narrowing. We studied the long-term effects of nedocromil on the maximal degree of airway narrowing to methacholine. Twenty-seven atopic asthmatic adults (21-39 years), with a measurable maximal-response plateau on the dose-response curve (20-55% fall in FEV1), were randomly allocated into two parallel treatment groups. They received either inhaled nedocromil 4 mg q.i.d. or placebo, for 8 weeks following a 2 week baseline period. Every 2 weeks, complete dose-response curves to inhaled methacholine were obtained. The response was measured by FEV1 and by volume history standardized partial expiratory flow-volume curves (V40p). A maximal-response plateau was considered if three or more of the highest data points fell within a 5% response range, the maximal response being the average value on the plateau (MFEV1, MV40p). Airway sensitivity was defined as the provocative concentration of methacholine causing a 20% fall in FEV1 (PC20FEV1) or 40% fall in V40p (PC40 V40p). Twenty-four subjects completed the study. Baseline FEV1 or V40p did not change during either treatment (P greater than 0.07). There were no significant changes in MFEV1 or MV40p during treatment with nedocromil (P greater than 0.07). Neither were these changes significantly different between the two groups (P greater than 0.25).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult

Validity of peak expiratory flow measurement in assessing reversibility of airflow obstruction.

BACKGROUND: Assessing the reversibility of airflow obstruction by peak expiratory (PEF) measurements would be practicable in general practice, but its usefulness has not been investigated. METHODS: PEF measurements were performed (miniWright peak flow meter) in 73 general practice patients (aged 40 to 84) with a history of asthma or chronic obstructive lung disease before and after 400 micrograms inhaled sulbutamol. The change in PEF was compared with the change in forced expiratory volume in one second (FEV1). Reversible airflow obstruction was analysed in two ways according to previous criteria. When defined as a 9% or greater increase in FEV1 expressed as a percentage of predicted values reversibility was observed in 42% of patients. Relative operating characteristic analysis showed that an absolute improvement in PEF of 60 l/min or more gave optimal discrimination between patients with reversible and irreversible airflow obstruction (the sensitivity and specificity of an increase of 60 l/min in detecting a 9% or more increase in FEV1 as a percentage of predicted values were 68% and 93% respectively, with a positive predictive value of 87%). When defined as an increase of 190 ml or more in FEV1, reversible airflow obstruction was observed in 53% of patients. Again an absolute improvement in PEF of 60 l/min or more gave optimal discrimination between patients with reversible and irreversible airflow obstruction (sensitivity 56%, specificity 94%, and positive predictive value 92%). CONCLUSION: Absolute changes in PEF can be used as a simple technique to diagnose reversible airflow obstruction in patients from general practice.

Adult

Auranofin in the treatment of steroid dependent asthma: a double blind study.

BACKGROUND: Long term administration of oral corticosteroids in patients with asthma may be associated with serious side effects. Non-steroidal anti-inflammatory drugs, including gold salts, have been shown to reduce the need for systemic corticosteroid treatment in uncontrolled studies. The effect of oral gold (auranofin) on asthma symptoms, lung function, and the need for oral prednisone treatment was investigated. METHODS: A 26 week randomised, double blind, placebo controlled, parallel group trial of auranofin was performed in 32 patients with moderately severe chronic asthma who required an oral corticosteroid dose of at least 5 mg prednisone a day (or equivalent) or 2.5 mg/day prednisone plus more than 800 micrograms/day inhaled corticosteroids. Auranofin was given orally in a dose of 3 mg twice daily. Asthma symptoms, lung function, and adverse effects were assessed at regular intervals. After 12 weeks of treatment prednisone dosage was tapered down by 2.5 mg every two weeks if the patient was clinically stable. Asthma exacerbations were treated with short courses of high doses of oral steroids. RESULTS: Twenty eight of the 32 patients, 13 in the placebo group and 15 in the auranofin group, completed the study. The total corticosteroid reduction achieved after 26 weeks of treatment was significantly greater (4 mg) in the auranofin group than in the placebo group (0.3 mg). The number of exacerbations requiring an increase of steroids was greater in the placebo group (2.1) than in the active group (0.9). A significant increase in FEV1 of 6.4% predicted occurred in the auranofin group during the study and there was a reduction of asthma symptoms such as wheezing and cough. There was no difference between the groups in peak flow measurements or in the number of asthma attacks. The incidence of side effects of auranofin was low, but exacerbations of constitutional eczema were noticeable. CONCLUSION: Auranofin provides an effective adjunct to treatment for steroid dependent asthma, leading to a reduction of oral steroid dose.

Adult

Lung sound intensity in patients with emphysema and in normal subjects at standardised airflows.

BACKGROUND: A common auscultatory finding in pulmonary emphysema is a reduction of lung sounds. This might be due to a reduction in the generation of sounds due to the accompanying airflow limitation or to poor transmission of sounds due to destruction of parenchyma. Lung sound intensity was investigated in normal and emphysematous subjects in relation to airflow. METHODS: Eight normal men (45-63 years, FEV1 79-126% predicted) and nine men with severe emphysema (50-70 years, FEV1 14-63% predicted) participated in the study. Emphysema was diagnosed according to pulmonary history, results of lung function tests, and radiographic criteria. All subjects underwent phonopneumography during standardised breathing manoeuvres between 0.5 and 2 1 below total lung capacity with inspiratory and expiratory target airflows of 2 and 1 l/s respectively during 50 seconds. The synchronous measurements included airflow at the mouth and lung volume changes, and lung sounds at four locations on the right chest wall. For each microphone airflow dependent power spectra were computed by using fast Fourier transformation. Lung sound intensity was expressed as log power (in dB) at 200 Hz at inspiratory flow rates of 1 and 2 l/s and at an expiratory flow rate of 1 l/s. RESULTS: Lung sound intensity was well repeatable on two separate days, the intraclass correlation coefficient ranging from 0.77 to 0.94 between the four microphones. The intensity was strongly influenced by microphone location and airflow. There was, however, no significant difference in lung sound intensity at any flow rate between the normal and the emphysema group. CONCLUSION: Airflow standardised lung sound intensity does not differ between normal and emphysematous subjects. This suggests that the auscultatory finding of diminished breath sounds during the regular physical examination in patients with emphysema is due predominantly to airflow limitation.

Aged

The effect of an inhaled neutral endopeptidase inhibitor, thiorphan, on airway responses to neurokinin A in normal humans in vivo.

Neuropeptides such as neurokinin A (NKA) have been proposed as important mediators of bronchoconstriction and airway hyperresponsiveness in asthma. Inhaled NKA causes bronchoconstriction in patients with asthma, but not in normal subjects. This is possibly due to the activity of an endogenous neuropeptide-degrading enzyme: neutral endopeptidase (NEP). We investigated whether a NEP-inhibitor, thiorphan, reveals bronchoconstriction to NKA or NKA-induced changes in airway responsiveness to methacholine in normal humans in vivo. Eight normal male subjects participated in a double-blind crossover study, using thiorphan as pretreatment to NKA challenge. Dose-response curves to inhaled NKA (8 to 1,000 micrograms/ml, 0.5 ml/dose) were recorded on 2 randomized days 1 wk apart, and methacholine tests were performed 48 h before and 24 h after the NKA challenge. Ten minutes prior to NKA challenge the subjects inhaled either thiorphan (2.5 mg/ml, 0.5 ml) or placebo. To detect a possible nonspecific effect of thiorphan, we investigated the effect of the same pretreatment with thiorphan or placebo on the dose-response curve to methacholine in a separate set of experiments. The response was measured by the flow from standardized partial expiratory flow-volume curves (V40p), expressed in percent fall from baseline. NKA log dose-response curves were analyzed using the area under the curve (AUC) and the response to the highest dose of 1,000 micrograms/ml (V40p,1000). The methacholine dose-response curves were characterized by their position (PC40V40p) and the maximal-response plateau (MV40p). Baseline V40p was not affected by either pretreatment (p greater than 0.15).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult

Potency of antileukoprotease and alpha 1-antitrypsin to inhibit degradation of fibrinogen by adherent polymorphonuclear leukocytes from normal subjects and patients with chronic granulomatous disease.

We have studied the relative efficacy of antileukoprotease (ALP) and alpha 1-antitrypsin (alpha 1AT) to inhibit the degradation of substrate by polymorphonuclear leukocytes (PMN) attached onto a fibrinogen matrix. PMN elastase activity was assayed by radioimmunoassay of a specific 21-residue cleavage product from the amino terminus of the A alpha chain, A alpha (1-21), of fibrinogen. The adherence of PMN (1.0 x 10(6)) to a fibrinogen matrix was facilitated by incubation with recombinant tumor necrosis factor-alpha (1 nM). Subsequently, the cells were exposed to inhibitors before stimulation with cytochalasin B and formylmethionyl-leucylphenylalanine. Under these conditions, ALP inhibited A alpha (1-21) formation with an IC50 of 85 +/- 30 nM and alpha 1AT gave an IC50 of 220 +/- 98 nM (mean +/- SD). The effect of oxidant production on A alpha (1-21) formation was evaluated by comparing the effect of PMN from normal subjects with PMN from subjects with X-linked NADPH oxidase deficiency. Stimulation of PMN from the latter subjects in a similar fashion as described above resulted in the formation of 40 +/- 4 pmol/ml A alpha (1-21), or approximately twice the amount seen with cells from normal subjects. Preincubation with ALP or alpha 1AT in a concentration range between 10 to 900 nM resulted in an IC50 of 50 +/- 13 nM for ALP compared with 150 +/- 21 nM for alpha 1AT. Both inhibitors are more effective to prevent fibrinogen degradation caused by chronic granulomatous disease (CGD) PMN than by normal PMN despite the fact that CGD PMN generated more A alpha (1-21) than did normal PMN.(ABSTRACT TRUNCATED AT 250 WORDS)

Cytochalasin B

Protective effect of pulmonary surfactant on elastase-induced emphysema in mice.

The aim of this study was to obtain some evidence of a protective role for pulmonary surfactant in the pathogenesis of emphysema. Firstly, we developed a quick and easy method to treat mice with a series of intratracheal instillations. Subsequently, three groups of mice were treated as follows: two groups received intratracheal instillations with pancreatic elastase (1.8 mg.kg-1 BW) followed after 3, 48 and 96 h in one group (El/Surf group) by intratracheal administration of surfactant (100 mg phospholipid.kg-1 BW), and in the other group by instillations with saline (El/s group). The third group of control mice was treated with saline followed by three doses of surfactant (s/Surf group). After eight weeks, the mice were killed and emphysema was measured by calculating the mean linear intercepts (Lm) of airspaces. The Lm values in the different groups were statistically tested for differences by the Mann-Whitney test. Instillation of pancreatic elastase (El/s group) resulted in an evenly distributed increase in Lm compared with the control group. Administration of surfactant in elastase-treated mice (El/Surf group) resulted in a statistically significant inhibition of airspace enlargement. Although the Lm in the El/Surf group was still higher than in the control group, analysis of histograms of Lm values per field of examination revealed that the Lm distribution in the former group was similar to that of the s/Surf group. The El/s group, on the contrary, showed the presence of many fields with enlarged air spaces. Repeated instillations with saline and/or surfactant had no effect on the Lm.(ABSTRACT TRUNCATED AT 250 WORDS)

Anesthesia, Inhalation

Long-term multicentre trial in chronic nonspecific lung disease: methodology and baseline assessment in adult patients. Dutch CNSLD Study Group.

Airways obstruction and airways hyperresponsiveness are two dominant features in patients with chronic nonspecific lung disease (asthma and chronic obstructive pulmonary disease (COPD)). We set up a study to determine whether long-term (3 yrs) therapeutic intervention directed at airways obstruction and hyperresponsiveness is superior to one directed at airways obstruction alone. Patients were selected on functional criteria (age, baseline forced expiratory volume in one second (FEV1), and airways hyperresponsiveness) and, furthermore, extensively characterized by history, smoking habits, allergy, reversibility of airways obstruction and quality of life. The methodology and practical problems of setting up this large multicentre study are outlined, together with an analysis of baseline data. Standardization of methods and techniques and recruitment of patients required much effort, recruitment taking about twice as long as expected. A 3 month feasibility study allowed us to eliminate minor problems in the protocol. Over a 16 month period, 274 adult patients (18-60 yrs) from the out-patient clinics of six university centres entered the study; 99 met the diagnostic criteria for asthma, 51 for COPD, 88 for asthmatic bronchitis, and 36 could not be classified. Their mean (SD) FEV1% pred was 65.1 (15.2)%. Their geometric mean provoking concentration of histamine producing a 20% fall in FEV1 (PC20 histamine) was 0.28 mg.ml-1. In a multiple regression analysis, more severe airways hyperresponsiveness was associated with lower prechallenge FEV1% pred (p less than 0.0001), higher pack-years of smoking (p = 0.0099), blood eosinophil count (p = 0.0004), skin test reactivity (p = 0.0047) and with female sex (p = 0.0302). We conclude that setting up long-term multicentre trials in chronic nonspecific lung disease (CNSLD) is feasible and that these may offer valuable information on treatment and outcome of the disease.

Adult

Detection of extracellular neutrophil elastase in hamster lungs after intratracheal instillation of E. coli lipopolysaccharide using a fluorogenic, elastase-specific, synthetic substrate.

Repeated intratracheal instillations of E. coli lipopolysaccharide (LPS) in hamster lungs cause an influx of polymorphonuclear leukocytes (PMNs) into the alveolar walls, with concomitant development of severe emphysema. It has been suggested that elastase, released by these PMNs, is involved in the development of emphysema. This study demonstrates the release of elastase from recruited PMNs in cryostat sections of hamster lungs, after being treated once, twice, or thrice with LPS, intratracheally. Elastase activity was visualized using two elastase-specific synthetic substrates, to which a methoxynaphthylamine (MNA) group had been bound covalently. Liberated MNA, when made insoluble by coupling with 5-nitrosalicylaldehyde, fluoresces strongly. The authors observed that the interval between start of incubation and appearance of fluorescence and the intensity of fluorescence correlated with the number of LPS administrations. Fluorescence was observed to be located in or in close vicinity to alveolar walls. No fluorescence was observed in sections of untreated hamsters. Liberation of MNA from synthetic substrates was delayed strongly by the addition of a recombinant secretory leukocyte proteinase inhibitor or a substituted cephalosporin neutrophil elastase inhibitor. The authors conclude that LPS-mediated PMN influx into the lung is accompanied by release of elastase from these cells and speculate that this PMN-elastase is involved in the development of LPS-mediated emphysema.

Animals

Oxidation-resistant variants of recombinant antileucoprotease are better inhibitors of human-neutrophil-elastase-induced emphysema in hamsters than natural recombinant antileucoprotease.

1. Antileucoprotease, being sensitive to oxidative inactivation, can be produced by recombinant techniques. Via site-directed mutagenesis, two mutants of recombinant antileucoprotease were produced in which one or more of the oxidation-sensitive methionine residues were replaced by leucine: in rALP242, methionine-73 was replaced by leucine, and in rALP231, leucine was substituted for four methionine residues. In vitro, native antileucoprotease and the recombinant antileucoprotease preparations have similar inhibitory characteristics towards human neutrophil elastase. We hypothesized that replacement of methionine residues in the antileucoprotease molecule would result in a reduced oxidation sensitivity of the mutants. 2. After incubation of recombinant antileucoprotease and its mutants with increasing dosages of cis-platinum(II)diammine dichloride, we observed that native antileucoprotease and recombinant antileucoprotease were inactivated by this reagent to the same extent. Compared with this, rALP242 was less inactivated, whereas the inhibitory capacity of rALP231 was not influenced by cis-platinum(II)diammine dichloride at all. 3. After incubation of recombinant antileucoprotease, rALP242 and rALP231 with triggered polymorphonuclear leucocytes, which are thought to produce an excess of oxidants, we measured residual inhibitory activities towards human neutrophil elastase of 10%, 55% and 87%, respectively. 4. In vivo, the inhibitory effects of intratracheally administered rALP242 and rALP231 towards human-neutrophil-elastase-induced emphysema were significantly greater than that of recombinant antileucoprotease. There were no significant differences between the mutants.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals

Oxygen-assisted exercise training in adult cystic fibrosis patients with pulmonary limitation to exercise.

Exercise training has been considered suitable only in cystic fibrosis (CF) patients with mild to moderate pulmonary dysfunction without progressive hypoxaemia during exercise. We trained 16 CF patients, all with advanced lung disease (mean standardized forced expiratory volume in 1 s (FEV1), 30% pred.), with a ventilatory limitation to exercise and a progressive hypoxaemia and hypercapnia at low maximal exercise capacity, Wmax (mean Wmax, 50% pred). Exercise training was performed on a cycle ergometer twice a day for 20 min at approximately 75% of the maximal predicted heart rate for at least 3 weeks. Supplemental oxygen was administered to reach a haemoglobin oxygen saturation of 90% during training. Patients considered malnourished because of a Quetelet Index of less than 20 kg m-2 received hyperalimentation orally or by duodenal tube (total 3500-4000 kcal day-1). Evaluation directly after the training period showed a statistically significant improvement in Wmax, maximal oxygen consumption, maximal minute ventilation, pulse, PaCO2 at rest, FEV1 and body weight. None of the pretraining variables was able to predict the outcome of the training programme in the individual patient. We detected no adverse effects of the programme. This study shows that oxygen-assisted exercise training in combination with correction of the nutritional status is safe and beneficial in CF patients with severe lung disease.

Adult

The protective effect of a beta 2 agonist against excessive airway narrowing in response to bronchoconstrictor stimuli in asthma and chronic obstructive lung disease.

Beta 2 agonists reduce airway hypersensitivity to bronchoconstrictor stimuli acutely in patients with asthma and chronic obstructive lung disease. To determine whether these drugs also protect against excessive airway narrowing, the effect of inhaled salbutamol on the position and shape of the dose-response curves for histamine or methacholine was investigated in 12 patients with asthma and 11 with chronic obstructive lung disease. After pretreatment with salbutamol (200 or 400 micrograms) or placebo in a double blind manner dose-response curves for inhaled histamine and methacholine were obtained by a standard method on six days in random order. Airway sensitivity was defined as the concentration of histamine or methacholine causing a 20% fall in FEV1 (PC20). A maximal response plateau on the log dose-response curve was considered to be present if two or more data points for FEV1 fell within a 5% response range. In the absence of a plateau, the test was continued until a predetermined level of severe bronchoconstriction was reached. Salbutamol caused an acute increase in FEV1 (mean increase 11.5% predicted in asthma, 7.2% in chronic obstructive lung disease), and increase in PC20 (mean 15 fold in asthma, fivefold in chronic obstructive lung disease), and an increase in the slope of the dose-response curves in both groups. In subjects in whom a plateau of FEV1 response could be measured salbutamol did not change the level of the plateau. In subjects without a plateau salbutamol did not lead to the development of a plateau, despite achieving a median FEV1 of 44% predicted in asthma and 39% in chronic obstructive lung disease. These results show that, although beta 2 agonists acutely reduce the airway response to a given strength of bronchoconstrictor stimulus, they do not protect against excessive airflow obstruction if there is exposure to relatively strong stimuli. This, together with the steepening of the dose-response curve, could be a disadvantage of beta 2 agonists in the treatment of moderate and severe asthma or chronic obstructive lung disease.

Adult

The effect of inhaled corticosteroids on the maximal degree of airway narrowing to methacholine in asthmatic subjects.

Airway hyperresponsiveness in asthma is characterized by an increase in sensitivity and in maximal response to airway-narrowing stimuli. Long-term therapy with inhaled corticosteroids is known to reduce airway hypersensitivity in asthmatic patients. To investigate whether these drugs also reduce the maximal degree of airway narrowing we studied the effects of inhaled budesonide on the maximal response plateau of the dose-response curve to inhaled methacholine in mildly asthmatic patients in whom a raised plateau could be measured. Sixteen atopic patients with mild asthma were placed randomly into two parallel treatment groups to receive double-blindly either budesonide (400 micrograms twice daily) or placebo, inhaled via a Turbuhaler, for 4 wk. Before treatment, after 2 and 4 wk of treatment, and after 2 and 4 wk of wash-out, complete dose-response curves to methacholine were obtained using a standardized 2-min tidal breathing method. The response was measured by FEV1, expressed in % fall from baseline. A plateau on the log dose-response curve was considered if three or more data points fell within a 5% response range. The maximal response was obtained by averaging the values on the plateau (MFEV1), and the sensitivity was calculated from the provocative concentration of methacholine, causing a 20% fall in FEV1 (PC20). After 4 wk of budesonide treatment, mean MFEV1 decreased from 41.6 to 33.7% fall (p = 0.0004). The changes in MFEV1 were significantly different between placebo and budesonide (p = 0.03). The geometric mean PC20 increased from 3.4 to 6.3 mg/ml (p = 0.02), but the changes in PC20 were not different between the two groups (p = 0.23).(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Inhalation

Lack of type II cells and emphysema in human lungs.

Ten surgically removed human lungs or lobes were studied, to assess the relationship between the abundance of type II alveolar epithelial cells and the degree of emphysema. Type II cell abundance (total number as well as percentage of the total parenchymal cell population) was determined in sections of randomly selected tissue samples of these lungs or lobes by using a type II cell specific antibody specific anti-lavage serum (SALS-Hu), which recognizes surfactant-associated proteins. In these tissue samples we also determined the degree of emphysema with the aid of a number of morphometric parameters, destructive index (DI), mean linear intercept (Lm in mm), and the number of normal alveolar attachments on (pre)terminal bronchioles (normal AA.mm.1). We subsequently calculated the Spearman rank correlation coefficients (rs) between the abundance of type II cells and parameters for emphysema. We found a significant negative correlation between the percentage of type II cells and DI at tissue sample level (rs = 0.55; p = 0.02). We also calculated correlation coefficients between the abundance of type II cells and the degree of small airways disease in (pre)terminal and respiratory bronchioles (SADscore), lung function, age and smoking habits. The results suggest a role for type II cells in the pathogenesis of emphysema.

Adult