The effect of naftidrofuryl on transcutaneous oxygen tension during a treadmill test in patients with peripheral arterial occlusive disease.

Tissue hypoxaemia can be evaluated by the noninvasive method of transcutaneous oxygen tension (tcpO2) measurement in patients with peripheral arterial occlusive disease (PAOD). The effects of naftidrofuryl (Praxilene) on exercise-induced tissue ischaemia was objectively assessed by continuously measuring the tcpO2 in 30 patients during three treadmill tests over a 3-month period in a randomized double-blind, placebo controlled, parallel group study. To be included in the study, the tcpO2 and total walking distance had to be stable during the washout period (D-15-D0). The area under the tcpO2 curves was scanned and automatically calculated after identification of baseline and the end of the treadmill test. The treadmill test on D30 and D90 was terminated at a similar walking distance to that obtained on D0. On D0 both groups were comparable (p = 0.22). The area under the curve (AUC) reduced significantly in the naftidrofuryl group between D0 and D30 (p < 0.001) and D0 and D90 (p < 0.001). However, no significant tcpO2 AUC reduction was found in the placebo group (D0-D30, p = 0.58; D0-D90, p = 0.50). This was confirmed by calculation of the percentage of patients whose percentage change in the AUC on D90 was higher than the upper limit of the 90% confidence interval, calculated from the percentage change over the washout period. Of the 15 patients receiving natfidrofuryl, 66.6% exceeded this upper limit, compared with only 7% of patients receiving placebo (p = 0.0017). This study shows that naftidrofuryl has a protective effect on exercise-induced tissue ischaemia as measured by the tcpO2 AUC in PAOD stage II patients.

Effect of a leukotriene B4 receptor antagonist SC-53228 on ozone-induced airway hyperresponsiveness and inflammation in dogs.

The importance of the potent neutrophil chemoattractant leukotriene (LT)B4 in causing ozone-induced bronchoconstriction, airway inflammation, and airway hyperresponsiveness in dogs was studied using the LTB4-receptor antagonist SC-53228. Seven dogs from random sources were studied three times, at least 2 wk apart. On each occasion, acetylcholine (Ach) airway responsiveness was measured before and 1 h after ozone (3 ppm, 30 min) or dry air inhalation, followed by a bronchoalveolar lavage (BAL). On the first day, dogs were treated with SC-53228 (0.4 mg/kg intravenously) followed by a continuous intravenous infusion of 1.2 mg/kg/h before ozone inhalation. On the other two days, diluent was infused followed by ozone or dry air inhalation. Cell counts were measured in BAL and cell activation was measured by spontaneous and by phorbol myristate acetate-stimulated (PMA) (2.4 mumol/L) oxygen radical release, measured from washed BAL cells (4 x 10(6) cells) by lucigenin-enhanced chemiluminescence. Ozone inhalation caused bronchoconstriction and airway hyperresponsiveness. SC-53228 inhibited the ozone-induced airway hyperresponsiveness (p = 0.006), but not the bronchoconstriction. Spontaneous (p = 0.004) and PMA-stimulated (p = 0.04) lucigenin-enhanced chemiluminescence were increased after ozone inhalation. The ozone-induced increases in PMA-stimulated chemiluminescence were significantly attenuated by treatment with SC-53228 (p = 0.04). These results suggest that LTB4 is involved in the pathogenesis of ozone-induced airway hyperresponsiveness, possibly through activation of airway inflammatory cell.

Role of airway eosinophils in the development of allergen-induced airway hyperresponsiveness in dogs.

The role of the eosinophil in the development of allergen-induced airway hyperresponsiveness is uncertain. We examined whether the development of airway hyperresponsiveness in 17 dogs after inhalation of Ascaris suum allergen (10(-6) to 10(-2) weight/volume [w/v]) was associated with increases in the number and level of activation of eosinophils before and after allergen inhalation. Airway responsiveness to inhaled acetylcholine was measured before and 24 h after Ascaris inhalation. Eosinophil number was assessed by bronchoalveolar lavage performed 1 wk before allergen inhalation and 15 min after the 24 h acetylcholine challenge. Dogs that developed Ascaris-induced airway hyperresponsiveness (n = 8) had a significantly greater number of bronchoalveolar lavage eosinophils before allergen inhalation (mean +/- SEM: 4.6 +/- 1.94 x 10(4) cells/ml) than dogs that did not become hyperresponsive (n = 9) (1.2 +/- 0.81 x 10(4) cells/ml) (p = 0.03). Ascaris-induced airway hyperresponsiveness, measured 24 h after allergen inhalation, was not associated with increases in eosinophil number after allergen challenge. These results suggest that the presence of airway eosinophils before allergen inhalation is necessary for the development of allergen-induced airway hyperresponsiveness.

The effects of an inhaled corticosteroid on oxygen radical production by bronchoalveolar cells after allergen or ozone in dogs.

Both ozone and allergen inhalation increase the capacity to produce oxygen radicals by bronchoalveolar lavage cells in dogs. The purpose of these studies was to determine whether inhaled corticosteroids inhibits these increases in oxygen radical production from bronchoalveolar lavage cells. Six random source dogs were studied after dry air or ozone inhalation (3 ppm, 30 min). Seven random source dogs were studied after diluent or allergen inhalation. The dogs inhaled budesonide (2.74 mg/day) or lactose powder, twice daily for 7 days before ozone and allergen. 90 min after ozone or dry air, and 24 h after Ascaris suum or diluent a bronchoalveolar lavage was carried out. Spontaneous luminol-enhanced chemiluminescence was measured from bronchoalveolar lavage cells (4 x 10(6) cells) for 10 min, followed by a measurement of phorbol myristate acetate (PMA 2.4 micromol/l) stimulated chemiluminescence for 10 min. Both ozone and allergen inhalation caused an increase in PMA stimulated chemiluminescence (P<0.05). Budesonide pretreatment inhibited ozone-induced (P<0.008), but not allergen-induced PMA stimulated chemiluminescence (P>0.90). Both ozone and allergen inhalation caused an increase in the bronchoalveolar lavage neutrophils. Budesonide pretreatment significantly inhibited the ozone-induced (P=0.007), but not the ascaris-induced neutrophil influx (P=0.93). These results demonstrate that ozone, but not allergen, stimulated oxygen radical release and neutrophil influx are attenuated by inhaled corticosteroids. This suggests that luminol-enhanced chemiluminescence from bronchoalveolar lavage cells measures oxygen radicals derived from neutrophils, and that ozone-and allergen-induced bronchoalveolar lavage neutrophilia are caused by different mechanisms.

Ozone-induced oxygen radical release from bronchoalveolar lavage cells and airway hyper-responsiveness in dogs.

1. Ozone inhalation causes airway hyper-responsiveness and airway inflammation in dogs. The purpose of this study was to determine whether these effects are associated with increases in oxygen radical production from bronchoalveolar lavage (BAL) cells. 2. Twelve randomly selected dogs were studied twice, 4 weeks apart. On each study day, acetylcholine (ACh) airway responsiveness was measured before and 1 h after ozone (3 p.p.m., 30 min) or dry air inhalation, followed by BAL. The response to ACh was expressed as the concentration causing an increase in lung resistance of 5 cmH2O l-1 s-1 above baseline. Spontaneous and phorbol myristate acetate (PMA) (2.4 mumol l-1)-stimulated oxygen radical release from washed BAL cells (4 x 10(6) cells ml-1) was measured by luminol-enhanced chemiluminescence in a luminometer at 37 degrees C. 3. Ozone inhalation caused airway hyper-responsiveness. The concentration of ACh causing an increase in lung resistance of 5 cmH2O l-1 s-1 (the 'provocative' concentration) fell from 4.68 mg ml-1 (% S.E.M., 1.43) before, to 0.48 mg ml-1 (% S.E.M., 1.60) after ozone (P < 0.0001). Spontaneous chemiluminescence area under the curve (AUC) significantly increased after ozone from 4.08 mV (10 min) (% S.E.M., 1.28) after dry air to 8.25 mV (10 min; % S.E.M., 1.29) after ozone (P = 0.007). Ozone inhalation also increased PMA-stimulated chemiluminescence AUC from 18.97 mV (10 min; % S.E.M., 1.18) after dry air to 144.03 mV (10 min; % S.E.M., 1.45) after ozone (P = 0.0001). The increase in PMA-stimulated chemiluminescence was significantly correlated with ozone-induced ACh airway hyper-responsiveness (r = 0.83, P < 0.001). 4. These results indicate that inhaled ozone increases oxygen radical release from BAL cells and suggest that oxygen radicals are important in causing ozone-induced airway hyper-responsiveness.

Allergen-induced oxygen radical release from bronchoalveolar lavage cells and airway hyperresponsiveness in dogs.

Allergen inhalation causes airway hyperresponsiveness and airway inflammation in dogs. The purpose of this study was to determine whether allergen-induced airway hyperresponsiveness is associated with increases in oxygen radical production from bronchoalveolar lavage (BAL) cells. A group of 10 random-source dogs were studied twice, 4 wk apart. On each occasion, acetylcholine (ACh) airway responsiveness was measured before and 24 h after inhalation of Ascaris suum or its diluent, followed by BAL. The response to ACh was expressed as the concentration causing an increase in lung resistance of 5 cm H2/O/L/s above baseline. Spontaneous and phorbol myristate acetate (PMA)-stimulated (2.4 mumol/L) oxygen radical release were measured, for 10 min each, from washed BAL cells (4 x 10(6) cells/ml) by luminol-enhanced chemiluminescence in a luminometer at 37 degrees C. Superoxide anion production was measured using a cytochrome c assay. Allergen inhalation caused bronchoconstriction, airway inflammation, and airway hyperresponsiveness. The acetylcholine provocative concentration fell from 7.47 mg/ml (% SEM 1.61) before to 1.23 mg/ml (% SEM 1.62) after allergen (p < 0.0001). Allergen inhalation significantly increased absolute neutrophil (p = 0.03) and eosinophil (p = 0.02) counts in BAL. Spontaneous (p < 0.0003) and PMA-stimulated (p < 0.0005) chemiluminescence and superoxide anion production (p = 0.039) were increased after allergen inhalation. The allergen-induced increases in chemiluminescence were significantly correlated with the increases in ACh airway hyperresponsiveness (r = 0.75, p < 0.012). These results indicate that inhaled allergen increases oxygen radical release from bronchoalveolar lavage cells and supports the hypothesis that oxygen radicals are important in causing allergen-induced airway hyperresponsiveness.

Effect of inhaled budesonide on ozone-induced airway hyperresponsiveness and bronchoalveolar lavage cells in dogs.

Inhaled corticosteroids are known to reduce components of the airway inflammation characteristic of asthma and improve airway hyperresponsiveness. However, the effect of inhaled corticosteroids on ozone-induced airway responses is unknown. Eight dogs inhaled budesonide [2.74 +/- 0.25 (SE) mg/day] or lactose powder twice daily for 7 days before inhaling ozone (3 ppm for 30 min) or dry air. Acetylcholine airway responsiveness was measured before and 1 h after ozone, followed by a bronchoalveolar lavage (BAL). The response to acetylcholine was expressed as the concentration causing an increase in lung resistance of 5 cmH2O.l-1.s above baseline (acetylcholine provocation concentration). Budesonide pretreatment significantly attenuated the ozone-induced increase in pulmonary resistance (P = 0.003) and neutrophil influx into BAL (P = 0.001) and significantly reduced BAL eosinophils (P = 0.026). However, budesonide pretreatment had no significant effect on ozone-induced airway hyperresponsiveness. After budesonide, the acetylcholine provocative concentration fell from 5.96 mg/ml (%SE 1.46) before to 1.11 mg/ml (%SE 1.63) after ozone (P = 0.006). After lactose, the acetylcholine provocative concentration fell from 5.34 mg/ml (%SE 1.40) before to 0.50 mg/ml (%SE 1.85) after ozone (P = 0.001). Dry air inhalation did not cause airway hyperresponsiveness (P = 0.68). These results suggest that ozone-induced airway hyperresponsiveness is steroid resistant and that airway neutrophils or eosinophils are not important in its pathogenesis.

Effect of an inhaled corticosteroid on airway eosinophils and allergen-induced airway hyperresponsiveness in dogs.

The presence of airway eosinophils before allergen inhalation may contribute to the development of allergen-induced airway responses. We examined whether a reduction in airway eosinophil numbers before allergen inhalation as a result of inhalation of the corticosteroid budesonide would prevent allergen-induced airway hyperresponsiveness in seven dogs. Acetylcholine airway responsiveness was measured before and 24 h after inhalation of Ascaris suum allergen (10(-6)-10(-2) wt/vol) or its diluent on 4 test days separated by > or = 4 wk. Dogs were pretreated for 7 days before and on the morning of each test day with inhaled budesonide (2.69 mg/day) or a placebo (lactose). Airway eosinophil numbers were assessed by bronchoalveolar lavage. Inhaled budesonide significantly reduced the number of airway eosinophils before allergen inhalation from 3.6 +/- 2.38 x 10(4) (SE) cells/ml after inhaled lactose to 0.3 +/- 0.21 x 10(4) cells/ml after inhaled budesonide (P = 0.028). The decrease in eosinophil number was associated with a significant reduction in allergen-induced airway hyperresponsiveness (P = 0.005). These results support the hypothesis that the number of eosinophils in the airways before allergen inhalation is an important determinant in the development of allergen-induced airway hyperresponsiveness in dogs.

Effect of FLAP antagonist MK-0591 on leukotriene production and ozone-induced airway responses in dogs.

We used the 5-lipoxygenase-activating protein (FLAP) antagonist MK-0591 to investigate the importance of leukotrienes (LT) in causing ozone-induced bronchoconstriction, airway inflammation, and airway hyperresponsiveness in dogs. Six random source dogs were studied. On one day, dogs were treated with MK-0591 (2 mg/kg iv) followed by a continuous intravenous infusion of 8 micrograms.kg-1.min-1. On the other day, the diluent was infused. Acetylcholine airway responsiveness was measured before and 1 h after ozone inhalation (3 ppm for 30 min). On each day, whole blood and bronchoalveolar lavage (BAL) cells were challenged with calcium ionophore to stimulate LTB4 production. Urinary LTE4 levels were measured before and after ozone. MK-0591 inhibited LTB4 production in whole blood by 96% (P = 0.001) and that from BAL cells by 91% (P = 0.001). By contrast, MK-0591 had no effect on ozone-induced bronchoconstriction, airway hyperresponsiveness, or influx of neutrophils into BAL. The mean log difference of the pre- to post-acetylcholine provocative concentration was 0.64 +/- 0.40 during MK-0591 treatment and 0.68 +/- 0.40 during diluent treatment (P = 0.71). These results indicate that peptidoleukotrienes are produced during ozone inhalation and that MK-0591 inhibits LT production in dogs. However, LTs do not play a role in ozone-induced bronchoconstriction, airway inflammation, or airway hyperresponsiveness in dogs.

Validity of ECSC prediction equations for spirometric indices in Dutch conscripts.

A study was performed to determine whether prediction equations issued by the European Community for Steel and Coal (ECSC) and the European Respiratory Society (ERS) fit spirometric data in young adult males. The study comprised 246 randomly selected Dutch conscripts, who participated in the study on the basis of informed consent. A questionnaire was used to assess respiratory symptoms and smoking habits. Maximal expiratory flow-volume curves were obtained with a rolling seal spirometer, and summary statistics selected according to ECSC/ERS recommendations. In addition, standing height and body weight were obtained. We analysed the data of 100 conscripts of European descent, with no history of respiratory symptoms. They were all life-long nonsmokers. Their mean (SD) age was 18 (0.12) yrs (range 17.9-19.0 yrs), with a mean (SD) standing height of 1.84 (0.06) m (range 1.68-2.00 m). The data for forced vital capacity (FVC), forced expiratory volume in one second (FEV1) and maximal mid-expiratory flow (MMEF) agreed well with ECSC predictions; 95% confidence intervals (95% CI) of differences between measured and predicted values were -0.174 to 0.044 l, -0.012 to 0.174 l.s-1 and -0.114 to 0.302 l.s-1, respectively. Peak expiratory flow was systematically larger than predicted, as was FEV1 % FVC (95% CI 0.74 to 1.31 l.s-1 and 2.50 to 5.24%, respectively), due to the intercept being inappropriate. The residual standard deviation in the conscripts was somewhat less than in the ECSC/ERS predictions equations, except for peak expiratory flow (PEF).(ABSTRACT TRUNCATED AT 250 WORDS)

The role of thromboxane in allergen-induced asthmatic responses.

In this study we evaluated the role of thromboxane in causing allergen-induced early and late asthmatic responses and airway hyperresponsiveness in asthmatic subjects. Twelve atopic subjects with stable asthma and documented early and late asthmatic responses to an inhaled allergen were treated with placebo or CGS 13080, a specific thromboxane synthetase inhibitor, given orally (200 mg four times daily) for two days before, the day of, and the day after allergen inhalation. Treatments were administered in a double-blind, placebo-controlled, crossover fashion. The effect of pretreatment with CGS 13080 was examined on serum TxB2 levels and the magnitude of the asthmatic responses after inhaled allergen. Serum TxB2 levels increased significantly from 96 ng.ml-1 (SEM 29) 3 h after diluent to 151 ng.ml-1 (SEM 27) 3 h after allergen (p = 0.008). CGS 13080 pretreatment markedly inhibited the levels of TxB2 at all time points before and after inhaled allergen (p = 0.0001) and had a small but significant effect on the magnitude of the early asthmatic responses after allergen (p = 0.0009). CGS 13080 did not alter either late asthmatic responses, baseline airway responsiveness, or the increase in histamine airway responsiveness after allergen. These results suggest that allergen-induced early asthmatic responses, but not late responses or allergen-induced airway hyperresponsiveness, are partly caused by thromboxane release.

Airway responsiveness to inhaled methacholine in patients with irritable bowel syndrome.

We examined whether patients with irritable bowel syndrome have increased airway responsiveness by measuring forced expiratory volumes in 1 second (FEV1) after inhalation of increasing concentrations of methacholine. Responses obtained in 11 IBS patients were compared with those obtained in 11 normal subjects and in 11 subjects with organic disease of the gut or its related organs. All subjects were selected so that other factors that might contribute to increased airway responsiveness were excluded. The methacholine concentration that caused a 20% fall in the FEV1 (PC20), as well as the reduction in FEV1 induced by each methacholine concentration, were used to assess airway responsiveness. The geometric mean PC20 was 197.6 mg/mL (%SEM, 1.15) for normal subjects, 83.9 mg/mL (%SEM, 1.51) for subjects with organic bowel disease (P = 0.012), and only 12.8 mg/mL (%SEM, 1.74) for IBS patients (P less than 0.0001). The 22.5% +/- 2.5% decrease in FEV1 induced by 64 mg/mL of methacholine in IBS patients was significantly greater than that of 12.3% +/- 1.5% observed in healthy subjects (P = 0.003). In contrast, the 15.7% +/- 2.0% decrease in FEV1 observed in patients with organic disease was not different from that seen in normal subjects (P = 0.189). We conclude that IBS is associated with increased airway responsiveness following challenge with methacholine.

Tachyphylaxis to inhaled methacholine in normal but not asthmatic subjects.

Methacholine inhalation tests measure airway responsiveness in asthmatic and normal subjects. Tachyphylaxis occurs with repeated methacholine inhalations in normal subjects. The purpose of this study was to examine the time course and mechanisms of methacholine tachyphylaxis in normal subjects and to determine whether this occurs in mildly asthmatic subjects. Fifteen normal and nine asthmatic subjects were studied on 2 study days, at least 48 h apart. Each day, two inhalation tests were carried out. On one day, subjects performed two methacholine inhalation tests 3 h later by a methacholine test. Results were expressed as the provocation concentration causing a 20% fall in forced expiratory volume in 1 s (FEV1), (PC20). All normal subjects developed methacholine tachyphylaxis. The mean PC20 increased from 47.3 mg/ml (%SE 1.34) to 115.6 (%SE 1.51) (P less than 0.0001) in a 3-h interval. This increase lasted for greater than or equal to 6 h (P = 0.012). Asthmatic subjects did not develop methacholine tachyphylaxis. Their mean methacholine PC20s were 1.6 mg/ml (%SE 1.4) and 1.5 (%SE 1.4) (P = 0.75) 3 h later. In two other series of experiments, normal subjects were pretreated with the cyclooxygenase inhibitors indomethacin (100 mg/day) or flurbiprofen (150 mg/day) or a placebo for 3 days before two methacholine tests 3 h apart. Both indomethacin and flurbiprofen significantly inhibited the development of methacholine tachyphylaxis. These results confirm that methacholine tachyphylaxis occurs in normal subjects, lasts greater than or equal to 6 h, and may occur through the release of inhibitory prostaglandins. By contrast, methacholine tachyphylaxis does not occur in asthmatic subjects.

Zinc: its relationship to osteoporosis in rheumatoid arthritis.

Preliminary studies indicate that plasma zinc concentrations, as estimated by atomic absorption spectrophotometry, are reduced in rheumatoid arthritis. A relationship has also been established between metacarpal index of osteoporosis and plasma zinc concentrations in rheumatoid subjects.