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Biomedical subjects

J H Dijkman

Publications and source records attributed to J H Dijkman.

At least 73 records · Page 4Linked to original sources
PubMed1992

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↗
PubMed1991

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↗
PubMed1991

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↗
PubMed1991

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↗
PubMed1991

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↗
PubMed1991

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↗
PubMed1991

Effect of human antileucoprotease on experimental emphysema.

Antileucoprotease (ALP), a potent inhibitor of human neutrophil elastase (HNE), may be a modulating factor in the pathogenesis of emphysema. Investigating the clearance of intratracheally-instilled ALP in hamsters, we observed a rapid clearance from the airway lumen within 60 min, whereafter the remaining 40% slowly decreased with a calculated half-life (T0.5) of 2.8 h. Lung tissue-associated ALP showed a peak at 40 min and slowly decreased (T0.5 approximately 3 h). In vivo efficacy of ALP on HNE-induced pulmonary lesions was studied by instillation of either 365 micrograms or 730 micrograms ALP, followed after 1 h by 420 micrograms HNE. Emphysema, haemorrhage and secretory cell metaplasia (SCM) were quantified 21 days after instillations. ALP was found to be able to inhibit emphysema and haemorrhage in a dose-related way, the decrease of haemorrhage being less pronounced. SCM was minimally affected. These results show that ALP inhibits efficiently the development of HNE-induced emphysema and, to a lesser extent, haemorrhage. We speculate that tissue-associated ALP might be responsible for this protection.

Animals↗
PubMed1990

Proteinase inhibitory activities of antileukoprotease are represented by its second COOH-terminal domain.

Antileukoprotease or secretory leukocyte proteinase inhibitor is a potent serine proteinase inhibitor produced by exocrine glands of the human body. This monomeric protein (107 amino acids) comprises two homologous domains. It is generally thought that Leu19-Arg20-Tyr21 in the NH2-terminal domain represent the trypsin inhibitory activity, whereas Leu72-Met73-Leu74 in the COOH-domain represent the chymotrypsin and elastase inhibitory activity. Besides Met73, antileukoprotease contains three additional methionine residues all located in the COOH-terminal domain. Treatment of antileukoprotease with different amounts of methionine-selective reagents such as myeloperoxidase in the presence of H2O2 and Cl-, or cis-platinumdiammine dichloride resulted in a dose-dependent inactivation of all inhibitory activities, suggesting that methionine residues are involved in these activities. By using specific synthetic substrates, it was observed that elastase is able to displace trypsin from the inhibitor molecule, indicating that the trypsin and elastase inhibitory sites are located close to each other or at the same site. Incubation of antileukoprotease or its recombinant COOH-terminal domain with an antileukoprotease-specific monoclonal antibody (MoAb15) resulted in a strong selective increase of the trypsin inhibitory activity. The results presented reveal strong evidence that the inhibitory activities of antileukoprotease against trypsin, chymotrypsin and elastase are represented by its COOH-terminal domain, and that methionine residues are involved in interactions with these proteinases.

Antibodies, Monoclonal↗
PubMed1990

The effect of an inhaled leukotriene antagonist, L-648,051, on early and late asthmatic reactions and subsequent increase in airway responsiveness in man.

We have investigated the protective effects of the inhaled cysteinyl leukotriene antagonist, L-648,051, on allergen-induced early asthmatic response (EAR) and late asthmatic response (LAR) and the subsequent changes in bronchial responsiveness to methacholine. Ten atopic men with asthma participated in a double-blind, crossover, placebo-controlled trial. All subjects had documented EAR and LAR to house dust-mite extract. Responsiveness to methacholine was measured the day before and the day after a standardized allergen-challenge test. L-648,051 was inhaled in two doses of 12 mg 20 minutes before and 3 hours after the allergen challenge. The response was obtained from FEV1 and flows from maximal (V40m) and partial (V40p) expiratory flow-volume curves. All subjects had an EAR and LAR during placebo therapy, but only a minority demonstrated an increase in methacholine responsiveness of more than one doubling dose. The ratio of V40m to V40p during methacholine challenge was higher than during both EAR and LAR (p less than 0.05). There was no difference between drug- and placebo-therapy periods in baseline function, EAR, LAR, ratio of V40m to V40p, and the allergen-induced hyperresponsiveness (p greater than 0.1). These results indicate that an effective aerosolized leukotriene antagonist in man does not protect against allergen-induced airflow obstruction, despite the evidence of an inflammatory response to allergen challenge. This suggests that either the potency or duration of activity of L-648,051 is limited or that leukotrienes C4 and D4 do not play a causative role in human allergic asthma.

Administration, Inhalation↗
PubMed1990

The Phadiatop in vitro test for allergy in general practice: is it useful?

A study was performed in order to assess the value of the Phadiatop, a new in vitro allergy test, in general practice. A total of 248 patients were screened for bronchial allergy with PRIST, RAST and the Phadiatop. Information about the patient's history and the results of the PRIST, Phadiatop and RAST tests were presented consecutively to the general practitioner and his diagnoses based on and evolving from these were evaluated and compared with the diagnosis of a specialist. The general practitioner's diagnosis based on the results of the Phadiatop was the closest of all the tests to the specialist diagnosis. It is concluded that Phadiatop is of great use in diagnosing bronchial allergy in general practice.

Adolescent↗
PubMed1990

Evidence of grass-pollen allergenic activity in the smaller micronic atmospheric aerosol fraction.

In June 1988, during the grass-pollen season in Leiden, The Netherlands, outdoor airborne particulate matter was collected and separated into fractions according to aerodynamic sizes (greater than or equal to 10 microns, 4.9-10 microns, 2.7-4.9 microns, 1.3-2.7 microns, 0.6-1.3 microns, less than or equal to 0.6 microns), with a cascade impactor mounted on top of a high volume sampler. The different fractions were tested for the presence of grass-pollen allergenic activity using a RAST-inhibition assay: specific IgE-antibody-containing patient serum was applied on the particle-loaded impaction strips, and the serum was recovered by descending elution for further analysis in the RAST. Simultaneously, continuous measurements were made of the airborne grass-pollen concentration using a volumetric pollen trap. Sampling observations lasting 7-9 hr during a period with relatively high airborne grass-pollen concentrations showed reliably detectable amounts of grass-pollen allergen, not only in the first impaction stage where intact pollen were collected, but also in the lower stages collecting the smaller, paucimicronic and submicron atmospheric aerosol fraction. It is evident that this result has serious implications for the understanding of the bronchial symptoms frequently seen in hay fever patients on days with high pollen concentrations in the air.

Air↗
PubMed1990

Prophylactic treatment of grass pollen-induced asthma with cetirizine.

In a double-blind randomized parallel-group study, six investigators enrolled 43 subjects to study the prophylactic effect of 10 mg cetirizine b.i.d. on grass pollen-induced asthma. The control group received 60 mg b.i.d. terfenadine, given to avoid withdrawals from the trial because of hay fever symptoms. Subjects were included in the study between the appearance of the first symptoms of hay fever and those of pollen-induced asthma. The hay fever and asthma symptoms, visual analogue scores (VAS), FEV1 and self-assessment data on complaints, salvage treatment and peak-flow values were statistically analysed. Both treatments were well tolerated, with a low and similar incidence of side-effects. During the last 3 weeks of treatment, six (32%) of the 19 subjects on cetirizine who were evaluable for efficacy remained free of asthma complaints, and another two (10%) had only a single minor attack. None had a grade 3 (incapacitating) attack. Conversely, only one (5%) of the 20 evaluable subjects on terfenadine remained complaint free, and all others (95%) had multiple attacks, which incapacitated three (15%) of them. Nasal obstruction, dyspnoea, morning peak flow, consumption of beta 2-mimetics and an efficacy index on asthma, combining complaints and rescue drug consumption, were significantly better on cetirizine (P less than 0.05). It is concluded that cetirizine is able to prevent the exacerbation of asthma induced by grass pollen.

Adolescent↗
PubMed1990

Relation between small airways disease and parenchymal destruction in surgical lung specimens.

The relation between small airways disease and parenchymal destruction was investigated in lungs and lobes removed at surgery from 27 patients aged 15-70 years. Eight of the 27 patients were life-long non-smokers. The degree of small airways disease was assessed by semi-quantitative grading (SAD score) and by measuring diameter and wall thickness of membranous bronchioles. Parenchymal destruction was measured in three ways. Firstly, the number of alveolar attachments on membranous bronchioles per millimetre of circumference (AA/mm) was counted; the number of broken attachments was subtracted from the total AA/mm to give the numbers of intact attachments (normal AA/mm). Secondly, a point counting technique was used to give a destructive index (DI). Thirdly, the mean linear intercept (Lm) was determined. Total and normal AA/mm correlated negatively with the SAD score of membranous bronchioles (rs = -0.48 and -0.51) and with wall thickness (rs = -0.37 and -0.45) and DI correlated with wall thickness (rs = 0.5) and with the SAD score of respiratory bronchioles (rs = 0.53). Lm did not correlate with indices of small airway disease and total and normal AA/mm did not correlate with diameter. Multiple regression analyses showed that the correlation of total AA/mm with the SAD score of membranous and respiratory bronchioles and with wall thickness were not confounded by age or smoking. It is concluded that small airways disease is related to destruction of peribronchiolar alveoli, and it is postulated that small airways disease has a direct role in the causation of centrilobular emphysema.

Adolescent↗
PubMed1990

The long-term effects of nedocromil sodium and beclomethasone dipropionate on bronchial responsiveness to methacholine in nonatopic asthmatic subjects.

We investigated the effects of long-term treatment with two anti-inflammatory drugs, nedocromil sodium and beclomethasone dipropionate, on airway hyperresponsiveness to methacholine (PC20), on baseline FEV1 and on the bronchodilating effect of a deep breath in 25 nonsteroid-dependent nonatopic asthmatic adults. In all subjects the prestudy PC20 was less than 8 mg/ml, the postbronchodilator FEV1 was greater than 75% predicted, and skin prick tests and RAST to 13 common allergens were negative. After 2 months run-in, the subjects were randomly allocated into 3 parallel treatment groups to inhale double-blind either 4 mg nedocromil (n = 9) or 100 micrograms beclomethasone (n = 8) or placebo (n = 8) 4 times daily for 4 months. PC20 was measured using the 2-min tidal breathing method. The effect of a deep breath was measured during methacholine-induced bronchoconstriction by standardized maximal and partial expiratory flow-volume curves and was expressed as a flow ratio (M/P ratio). Pretreatment values of FEV1, PC20, and M/P ratio were not different between the 3 groups. PC20 did not change in the placebo group, but increased significantly by a factor of 3 after 8 wk of treatment with beclomethasone or nedocromil (p less than 0.001). FEV1 did not change after treatment with placebo or nedocromil (p greater than 0.2), but increased (mean change 0.2 L, SD 0.2) after 4 wk of treatment with beclomethasone (p less than 0.05). Geometric mean M/P ratio increased from 1.98 to 2.66 after 4 wk of beclomethasone (p less than 0.01), but not after nedocromil or placebo.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1990

Quality of life in elderly patients with chronic nonspecific lung disease seen in family practice.

We studied the quality of life of elderly patients with chronic nonspecific lung disease (CNSLD) in family practice. We also investigated the relationship between patients' somatic condition and their quality of life. Seventy patients, aged 40 years or older, with a diagnosis or symptoms of CNSLD completed the Sickness Impact Profile (SIP) and the list of daily activities (DAL). Pulmonary function (FEV1, IVC) and respiratory symptoms were assessed. The results indicated that patients were more impaired in their physical and psychosocial functioning than healthy control subjects. Most lung function parameters showed no correlation with the SIP scores. The respiratory symptoms of wheezing and dyspnea were related to patients' quality of life. Patients with chronic obstructive pulmonary disease (COPD) were more restricted in their daily functioning than patients with asthma. Since the relationship between patients' somatic condition and their quality of life is weak, we recommend comprehensive care that encompasses psychosocial as well as somatic interventions.

Activities of Daily Living↗