Chronic obstructive pulmonary disease from science to the clinic: the role of glutathione in oxidant-antioxidant balance

The data presented in this manuscript suggest that there is a profound change in oxidant/anti-oxidant balance in smokers and in patients with chronic obstructive pulmonary disease, particularly during exacerbations. This may be important in the pathogenesis of the condition. The antioxidant glutathione appears to be a critical protective mechanism in the distal airspace against oxidant-induced damage to epithelial cells. Studies of the regulation of antioxidants in the lungs, including glutathione, may well lead to the development of new therapeutic options to enhance the oxidant screen in the lungs, which should be useful in many conditions of lung inflammation.

Total daily energy expenditure relative to resting energy expenditure in clinically stable patients with COPD

BACKGROUND

An elevated resting energy expenditure (REE) commonly occurs in patients with chronic obstructive pulmonary (COPD). The purpose of this study was to investigate the effect of an increased REE on total daily energy expenditure (TDE) in 20 patients with COPD (19 men) with mean (SD) forced expiratory volume in one second of 37 (14)% predicted.

METHODS

TDE was measured over a two week interval using doubly labelled water. Fat-free mass (FFM) was calculated from total body water assessed by deuterium dilution. REE was measured by indirect calorimetry using a ventilated hood system.

RESULTS

The patients (10 men) with a significantly higher REE than those with a normal REE (median difference 205 kcal/ 24 h, p < 0.05) had a comparable TDE (hypermetabolic at rest: median 2593; range 2127-3083 kcal/24 h, normometabolic at rest: median 2629; range 2032-3179 kcal/ 24 h). There was no difference in mean daily heart rate (HR) between the groups (hypermetabolic at rest: median 92 (range 82-98), normometabolic at rest: median 98 (range 75-116) beats/min) or in the variation in the heart rate during the day. By means of multiple regression analysis it was shown that REE did not correlate significantly with TDE when FEM was taken into account.

CONCLUSIONS

This study shows that there is no significant difference in free living TDE between clinically stable patients with COPD with a normal REE and those with an increased REE. The variation in TDE in patients with COPD appears to reflect differences in energy expenditure for activities, but not differences in REE.

Influence of inspired oxygen concentration on deadspace, respiratory drive, and PaCO2 in intubated patients with chronic obstructive pulmonary disease

OBJECTIVES

To investigate the response of CO2-retaining chronic obstructive pulmonary disease (COPD) patients to an increase in FIO2 following a period of mechanical ventilation with PaO2 in the normal range. The administration of a high FIO2 to chronic obstructive pulmonary disease (COPD) patients may result in hypercapnia. Recent evidence indicates that the hypercapnia may be due to reversal of preexisting regional hypoxic pulmonary vasoconstriction resulting in a greater deadspace. This effect would be more pronounced in patients whose initial PaO2 was < 60 torr (< 7.9 kPa).

DESIGN

Single blinded, prospective study.

SETTING

A medical surgical intensive care until in a tertiary care, teaching hospital.

PATIENTS

COPD CO2-retaining patients.

INTERVENTIONS

FIO2 increased to 0.7.

MEASUREMENTS AND MAIN RESULTS

Twelve intubated COPD patients weaned from mechanical ventilation were studied both at their baseline FIO2 (0.3 to 0.4), and following a 20-min period of exposure to an FIO2 of 0.7. Mean baseline values were: PaO2 of 85 torr (11.3 kPa), PCO2 of 56 torr (7.5 kPa), deadspace of 73%, and respiratory drive normal, as measured by P0.1. Statistical analysis using the paired Student's t-test showed that the PaO2 increased significantly when the FIO2 was increased to 0.7, but there was no significant change in PaCO2, deadspace, or respiratory drive.

CONCLUSION

These results show that following a period of mechanical ventilation with an FIO2 sufficient to maintain a normal PaO2, a further increase in FIO2 does not result in an increased PaCO2 in this group of CO2-retaining COPD patients.

In situ expression of ICAM-1 and its mRNA in the lung tissue of asthmatic rats

In situ expression of ICAM-1 and ICAM-1 mRNA on the lung tissue of asthmatic rats was studied by immunohistochemical staining and in situ hybridization, respectively. The results showed that in normal rats ICAM-1 expression was rare on the endothelium of pulmonary artery and vein, and on the bronchial and alveolar epithelium. The distribution of ICAM-1 expression on the different part of lung tissue of asthmatic rats was similar to that of normal rats, but the level of ICAM-1 expression was significantly increased on the endothelium of pulmonary artery (EPA) and vein (EPV), bronchial epithelium (BEP) and alveolar epithelium (AEP) compared with those of normal and sensitized controls. The distribution and expression of ICAM-1 mRNA on the different part of lung tissue of normal and asthmatic rats were similar to that of ICAM-1 expression. In asthmatic rats, the expression of ICAM-1 mRNA on AEP and EPV was increased significantly compared with those of normal and sensitized controls. It is concluded that the increase of ICAM-1 expression on endothelium of pulmonary vessels, epithelium of broncheoli and alveoli may play an important role of inflammatory cell infiltration in asthmatic rats, and the increased expression of ICAM-1 in asthmatic rats was caused by the increase of expression of ICAM-1 mRNA.

Nedocromil sodium in obstructive airways disease: effect on symptoms and plasma protein leakage in sputum

In patients with asthma or chronic obstructive pulmonary disease, there is chronic airway inflammation with increased leakage of plasma proteins into the airway lumen, which can be reduced by inhaled glucocorticosteroids. Nedocromil sodium is an anti-inflammatory drug, and we questioned whether it also affects the leakage of plasma proteins. In a double-blind placebo-controlled study we investigated the effect of 12 weeks of treatment with nedocromil on forced expiratory volume in one second (FEV1), provocative concentration of histamine causing a 20% fall in FEV1 (PC20), peak flow, symptom scores, and plasma protein leakage in sputum, in 31 patients with obstructive airways disease and sputum production (mean (range) FEV1 61% of predicted (42-87%); geometric mean (range) PC20 0.39 (0.04-2.9) mg x mL(-1)). As a measure for plasma protein leakage we calculated the relative coefficients of excretion (RCE) of proteins from serum to the soluble phase of sputum. There was a small increase in morning and evening peak flow (p<0.05) and a decrease in night-time bronchodilator use (p<0.02) in favour of nedocromil. The RCE of alpha2-macroglobulin to albumin significantly decreased after treatment with nedocromil (p=0.03). The results show limited clinical efficacy of nedocromil in our study group. They further suggest that the anti-inflammatory properties of nedocromil extend to inhibition of plasma protein leakage into the airways.

[Skeletal muscle abnormalities in chronic obstructive lung disease with respiratory insufficiency. Value of P31 magnetic resonance spectroscopy]

31P magnetic resonance spectroscopy (31P MRS) is a non-invasive method to evaluate high energy compounds [adenosine triphosphate (ATP), phosphocreatin (PCr), inorganic phosphates (Pi)] and intracellular pH (pHi) of skeletal muscle during exercise and recovery. It is a clinically applicable method of investigation for severe COPD patients with respiratory failure since exercise is limited to a single group of muscle (calf). Pronounced alterations of muscular metabolism have been shown in these patients: (1) reduced aerobic capacity (as reflected by the ratio of Pi/PCr as a function of power and changes in recovery kinetics of PCr after exercise and (2) increased anaerobic metabolism (reflected by a decrease in intracellular pH). Four different studies reveal similar abnormalities. Acute oxygen administration partially improves these parameters, suggesting that other factors in addition to hypoxaemia may contribute to the metabolic impairment. The effect of increased physical activity on these abnormalities deserve further investigations.

Attenuation of oxidant/antioxidant imbalance during treatment of exacerbations of chronic obstructive pulmonary disease

BACKGROUND

An oxidant/antioxidant imbalance is thought to occur in patients with chronic obstructive pulmonary disease (COPD). It has recently been shown that during exacerbations of COPD the antioxidant capacity and protein sulfhydryls of plasma are lower and the levels of products of lipid peroxidation are higher than in age matched healthy subjects. The aims of this study were to confirm these data and to measure the time course of these changes.

METHODS

The plasma Trolox equivalent antioxidant capacity (TEAC), protein sulfhydryls, and products of lipid peroxidation were measured throughout the course of treatment in 13 patients who presented with an acute exacerbation of COPD.

RESULTS

TEAC values (mmol/l) were low on admission (mean 0.67, 95% confidence interval (CI) 0.32 to 0.88; p < 0.05) and had increased by discharge (0.98, 95% CI 0.88 to 1.2; p < 0.05) but still remained lower than in healthy subjects (1.33, 95% CI 1.11 to 1.65). There was also restoration of plasma protein sulfhydryl levels (mmol/l) from admission (0.32, 95% CI 0.20 to 0.43) to discharge (0.49, 95% CI 0.42 to 0.62, p < 0.001) to levels similar to those in healthy subjects (0.52, 95% CI 0.43 to 0.65). Products of lipid peroxidation, measured as thiobarbituric acid-malondialdehyde adducts (mumol/l), were significantly higher (2.08, 95% CI 1.8 to 2.5) than in control subjects (1.3, 95% CI 0.85 to 1.32; p < 0.01) and returned to normal values by the time of discharge (1.2, 95% CI 0.88 to 1.29).

CONCLUSIONS

These data confirm the presence of a profound oxidant/antioxidant imbalance in the blood of patients with acute exacerbations of COPD which returns towards normal values during the course of treatment.

Arm training reduces the VO2 and VE cost of unsupported arm exercise and elevation in chronic obstructive pulmonary disease

BACKGROUND

Patients with severe chronic obstructive pulmonary disease (COPD) may develop dyspnea with minimal arm activity, thoracoabdominal dyssynchrony with unsupported arm exercise (UAEX) and increased oxygen uptake (VO2), and minute ventilation (VE) with simple unsupported arm elevation (UAE) and UAEX. We investigated whether unsupported arm training, as the only form of exercise, could decrease the VO2 and VE cost (percentage increase from resting baseline) associated with unsupported arm elevation and exercise, respectively.

METHODS

Twenty-six patients with severe COPD were randomized to 21-24 sessions of unsupported arm (ARMT) or low-intensity resistive breathing (RBT) training as the only form of exercise. Patients were studied before and after training using a metabolic cart and esophageal and gastric pressures to evaluate metabolic and respiratory muscle function.

RESULTS

After ARMT, the VO2 (58% vs 38% increase, P < 0.05) and VE (41% v. 21% increase, P < 0.05) cost for UAEX at exercise isotime decreased and endurance time increased. Similarly the VO2 (25% vs 18% increase, P < 0.05) cost decreased and VE no longer increased in response to 2 minutes of UAE after ARMT. The RBT group showed no such change. No improvement in ventilatory load or respiratory muscle function could be identified to explain the physiologic changes observed. After ARMT, mean inspiratory flow (VT/TL), a measure of central respiratory drive, was reduced during UAEX and the expected increase during UAE did not occur.

CONCLUSION

We conclude that arm training reduces the VO2 and VE cost of UAE and UAEX, possibly through improved synchronization and coordination of accessory muscle action during unsupported arm activity.

Role of the thermic effect of food in malnutrition of patients with chronic obstructive pulmonary disease

Malnutrition in patients with chronic obstructive pulmonary disease (COPD) is classically ascribed to an increased resting energy expenditure (REE) secondary to high cost of breathing. However, malnutrition correlates only weakly with the severity of respiratory dysfunction, which suggests other mechanisms. The aim of the present study was to determine the possible role of diet-induced thermogenesis (DIT). Therefore, we evaluated the relationship between DIT and nutritional status, in particular fat-free mass (FFM) estimated by bioelectrical impedance analysis in 26 patients with stable COPD (mean FEV1 +/- SEM = 36.5 +/- 3.8% of predicted). Ten patients were undernourished (weight < 90% of ideal body weight [IBW] and/or FFM < 69% of IBW), and 16 were normally nourished. Diet-induced thermogenesis was determined by comparing postprandial energy expenditure and REE, the latter being measured after an overnight fast and the former over 4 h after a mixed test meal of 0.4 times REE load. No statistical difference in DIT was found between undernourished and eutrophic patients. There was no relationship between DIT and nutritional or functional parameters, notably FFM. These results suggest that malnutrition is not a consequence of an increased DIT.

Ventilatory response to positive and negative work in patients with chronic obstructive pulmonary disease

In healthy subjects, oxygen consumption and cardiorespiratory responses are lower during eccentric exercise (negative work, Wneg) than during concentric exercise (positive work, Wpos) at the same work load. The aim of the present study was to investigate the ventilatory response to Wneg in patients with chronic obstructive pulmonary disease (COPD). The study population consisted of 12 subjects with COPD [forced expiratory volume in 1 s (FEV1) mean (SD): 1.5 (0.4) 1, 46 (16)% of predicted]. Concentric and eccentric exercise tests (6 min exercise; interval > or = 1 h) were performed in random order at constant work loads of 25 and 50% of the individual maximal (positive) work capacity. Expired ventilation per minute (VE), oxygen consumption (VO2) and carbon dioxide production (VCO2) were 30% lower during Wneg than during Wpos for both work intensities. The breathing reserve during 25% Wneg was 11 (8)% and during 50% Wneg was 18 (14)% higher than during Wpos at corresponding work loads (P < 0.01). VE/VO2 and VE/VCO2 were similar during Wpos and Wneg. Arterial carbon dioxide tension (PaCO2) increased by 0.1 (0.4) kPa during 50% Wneg and by 0.7 (0.5) kPa during 50% Wpos (P < 0.01). During 50% Wneg' perceived leg effort (modified Borg scale) tended to be higher than perceived breathlessness (2.4 (1.2) vs. 2.0 (1.1). It was concluded that in subjects with COPD, the ventilatory requirements of Wneg were considerably lower than those of Wpos at similar work loads up to 50% of maximal work capacity. During Wneg, the ventilatory reserve was higher and gas exchange was less disturbed as a result of a lower VO2 and VCO2.

Comparative measurement of lung deposition of inhaled fine particles in normal subjects and patients with obstructive airway disease

Particulate pollutants have been suggested as a risk factor for increase in mortality and morbidity in patients with obstructive airway disease. In the present study we hypothesized that enhanced particle deposition dose is an underlying factor for such a finding. We measured lung deposition in normal healthy control subjects (N; n = 10) and in subjects with varying levels of airway obstruction: smokers (S; n = 10), smokers with small airways disease (SAD; n = 10), asthmatics (A; n = 5), and patients with chronic obstructive airway disease (COPD; n = 10). The subjects inhaled a uniform size sebacate aerosol (1-micron diameter) from a collapsible bag of a known volume (500 ml) repeatedly for as many as 15 breaths at a rate of 30 breaths/min. Aerosol concentration was monitored continuously at the mouth by a laser aerosol photometer. After correcting for particle loss in the bag, lung deposition fraction [DF = (inhaled minus exhaled)/inhaled], was determined breath by breath. DF values (mean +/- SD) were 0.14 +/- 0.02, 0.16 +/- 0.02, 0.21 +/- 0.05, 0.22 +/- 0.02 and 0.028 +/- 0.03 for N, S, SAD, A, and COPD, respectively. DF values in S, SAD, A, and COPD were 16, 49, 59, and 103% greater, respectively, than that of normal subjects (p < 0.05). DF of COPD was also greater than that of SAD or A (p < 0.05). No difference was found between SAD and A. When all of the subject data were combined, DF was correlated well with percent predicted FEV1 and FEF25-75 (r2 = 0.63 in both). The results indicate a marked increase in particle deposition in patients with obstructive lung disease, and this can be an important factor for the development of the adverse health effects of pollutant particles on the one hand and for the treatment of patients with drug aerosols on the other.

Effects of inhaled and oral glucocorticoids on inflammatory indices in asthma and COPD

The role of glucocorticoids in the treatment of chronic obstructive pulmonary disease (COPD) is controversial. We have previously described high numbers of neutrophils and high concentrations of the inflammatory cytokines interleukin-8 (IL-8) and tumor necrosis factor-alpha (TNF-alpha), and of the cell activation markers eosinophil cationic protein (ECP), eosinophil peroxidase (EPO), myeloperoxidase (MPO), and human neutrophil lipocalin (HNL) in COPD patients as compared with controls, and have postulated that the cytokines TNF-alpha and IL-8 play a role in propagating the inflammatory response in COPD. We have now studied the effects of inhaled and oral glucocorticoids on these inflammatory indices in induced sputum. Initially, we studied the effect of a 2-wk course of inhaled budesonide (800 mg twice daily for 2 wk) in 13 patients with severe COPD (mean FDV1: 35% predicted). There was no clinical benefit in either lung function or symptom scores, and no significant change in the inflammatory indices as measured by total and differential cell counts and concentrations of TNF-alpha eosinophil activation markers ECP and EPO, and neutrophil activation markers MPO and HNL. Because the lack of anti-inflammatory effect might have been due to poor drug delivery as a result of severe airflow limitation, we undertook a study examining the antiinflammatory effect of oral prednisolone (30 mg daily for 2 wk) in patients with COPD and undertook the same measurements in 10 patients with atopic asthma. Sputum eosinophil numbers, ECP, and EPO were significantly reduced in the asthmatic patients but were not modified in COPD. This confirms the clinical impression that inhaled steroids have little antiinflammatory effect, at least in the short term in this group of patients, and suggests that the inflammatory process in COPD is resistant to the antiinflammatory effect of glucocorticoids.

Total free living energy expenditure in patients with severe chronic obstructive pulmonary disease

Resting energy expenditure (REE) is often elevated in patients with chronic obstructive pulmonary disease (COPD), but no data are available regarding total energy expenditure in free living conditions. We compared total daily energy expenditure (TDE) in eight COPD patients (FEV1 36 +/- 13%) admitted to a pulmonary rehabilitation center and eight independently living healthy subjects, matched for sex, age, and body mass index (BMI). TDE was measured over a 2-wk interval using doubly labeled water in combination with measurement of REE and body composition. The COPD patients had a significantly higher TDE than the healthy subjects (2,499 +/- 320 kcal/d and 2,107 +/- 88 kcal/d, respectively, p < 0.01). The nonresting component of TDE (TDE-REE: physical activity and diet-induced thermogenesis [DIT]) was significantly higher in the COPD patients than in the healthy subjects, resulting in a ratio between TDE and REE of 1.7 +/- 0.2 and 1.4 +/- 0.1, respectively (p < 0.01). The results indicate that COPD patients exhibit an increased TDE in comparison with healthy subjects. The difference could by attributed to an increase in the nonresting component of TDE, since REE was comparable between the groups.

Granulocyte activation markers in induced sputum: comparison between chronic obstructive pulmonary disease, asthma, and normal subjects

Airway inflammation is present in asthma and is thought to play a significant part in the development of airflow obstruction. In chronic obstructive pulmonary disease (COPD), neutrophilic inflammation is present in the airway lumen, whereas the submucosa displays a lymphocytic infiltrate. Less is known about the nature and mechanisms of inflammation in COPD than in asthma. Induced sputum allows noninvasive sampling of respiratory tract secretions from patients and control subjects, allowing characterization of cells and measurement of soluble markers. We exploited this technique in order to compare the presence and quantify specific markers of eosinophil and neutrophil activation in subjects with asthma or COPD, and control subjects. Differential cell counts showed significantly higher neutrophil percentages in the patients with COPD compared with other groups, while patients with asthma had higher numbers of eosinophils. The neutrophil markers myeloperoxidase (MPO), from primary granules in neutrophils, and human neutrophil lipocalin (HNL), released from secondary granules, were elevated in patients with asthma and COPD compared with control subjects but markedly more so in COPD. The difference between COPD and asthma was more marked for HNL than for MPO suggesting that HNL may be a better marker for discriminating between these conditions. Concentrations of the eosinophil granule protein, eosinophil cationic protein (ECP), and the eosinophil granule-derived enzyme, eosinophil peroxidase (EPO) were raised in the patients with asthma and those with COPD.

The concentration of sodium, potassium pumps in chronic obstructive lung disease (COLD) patients: the impact of magnesium depletion and steroid treatment

OBJECTIVES

To evaluate the concentrations of magnesium (Mg), potassium (K) and sodium,potassium pumps (Na,K pumps) in skeletal muscle in patients with chronic obstructive lung disease (COLD) treated with or without diuretics.

DESIGN

An open cross-sectional study.

SETTING

COLD patients admitted to the Medical Department of Vejle Hospital, Denmark.

SUBJECTS

Thirty-six consecutive COLD patients and 23 age- and sex-matched controls.

MAIN OUTCOME MEASURES

Biopsies of skeletal muscle were performed in patients and controls for measurements of Mg, K and Na,K pumps. In a parallel animal experiment the influence of medical treatment on the concentration of Na,K pumps in skeletal muscle was evaluated by infusing 10-week-old rats for 14 days with vehicle, terbutaline, or dexamethasone.

RESULTS

In the patients, mean muscle Mg and K concentrations were reduced by 22 and 14% respectively (P < 0.001), but in those patients who received diuretics muscle Mg and K were further reduced (by 31 and 27%, respectively, of the control values). The concentration of Na,K pumps was increased by 31% (P < 0.001), with a maximum increase of 61% (P < -0.001) in 12 intensive care patients receiving high dosages of glucocorticoids. Linear regression analysis showed a positive correlation between daily glucocorticoid intake and the concentration of Na,K pumps in the biopsy specimens from each patient (r = 0.38, P = 0.02). In the experimental study, dexamethasone induced 27-34% increase in the concentration of Na,K pumps (P < 0.01) in three different muscles, whereas there was no significant change following terbutaline infusion.

CONCLUSIONS

COLD patients show reduced concentrations of Mg and K in skeletal muscle, associated with an upregulation of the Na,K pump concentration. It is plausible that this upregulation may be caused by glucocorticoid treatment. The clinical benefits of glucocorticoids may in part be due to an increase in the activity and capacity of the Na,K pump and thereby in a possible enhancement of muscle force.

Analysis of body water compartments in relation to tissue depletion in clinically stable patients with chronic obstructive pulmonary disease

Tissue depletion often occurs in patients with chronic obstructive pulmonary disease (COPD), even in those that are weight-stable. Limited data are available, however, about changes in body water compartments in chronic wasting diseases such as COPD. The purpose of this study was to measure body composition in severe COPD patients with special attention to fat-free mass (FFM) depletion and the distribution of body water compartments. Total body water (TBW) and extracellular water (ECW) were measured by deuterium and sodium bromide dilution techniques, respectively, in 38 COPD patients (age: 65 +/- 9 y, forced expiratory volume in 1 s: 38 +/- 14% of predicted) in a stable clinical condition. FFM was calculated by assuming a hydration coefficient of 73%. Underweight patients [body mass index (BMI; in kg/m2) < or = 21] were characterized by a significantly lower percentage fat mass than normal-weight patients, but no significant difference was found in the ratio of ECW to intracellular water (ICW)(BMI < or = 21: 0.72 +/- 0.12, BMI > 21: 0.71 +/- 0.16; NS). When the study population was divided into depleted patients (FFM/height2 < or = 15 kg/m2) and nondepleted patients (FFM/height2 > 15 kg/m2), there was no significant difference in the percentage fat mass, but the ECW-ICW ratio was significantly higher in the depleted patients (0.78 +/- 0.16) than in the nondepleted patients (0.66 +/- 0.12, P < 0.05); this was most pronounced in women. In conclusion, it was found that COPD patients with extreme FFM wasting are characterized by an increased ECW-ICW ratio despite a relatively spared fat mass.

Pulmonary concentrations of dirithromycin and erythromycin during acute exacerbation of mild chronic obstructive pulmonary disease

We compared the concentrations of dirithromycin and erythromycin at steady state in serum and the intrapulmonary region in patients suffering from acute exacerbation of mild chronic obstructive pulmonary disease. Twenty patients received dirithromycin, 500 mg given orally once daily for five consecutive days. The other 20 patients were treated with erythromycin base, which was administered orally four times daily at a total daily dose of 1000 mg for seven days. All patients were divided into eight groups, with five subjects in each group, according to sampling times (2, 4, 8, and hrs after the last dose) and treatment. After the erythromycin treatment mean serum concentrations were higher than those of dirithromycin treatment mean serum concentrations were higher than those of dirithromycin for upto 4 hours, but they were undetectable 24 hours after the last dose. At all time periods, the concentrations of dirithromycin in bronchial secretion, bronchial mucosa and epithelial lining fluid were greater than the concentration in serum. Concentrations of erythromycin were always lower than those of dirithromycin in the explored pulmonary sites. Our data demonstrated that a five day course of 500 mg of dirithromycin once daily induced higher concentrations and longer persistence in the various potential sites of pulmonary infection than a seven day course of 250 mg of erythromycin every 6 hrs. The shorter duration of therapy and the once daily dosing with good efficacy against common respiratory pathogens would be advantageous for patients and would be likely to promote better patient compliance and acceptability.

Gastrin levels in serum and bronchoalveolar lavage fluid of patients with lung cancer: comparison with patients with chronic obstructive pulmonary disease

BACKGROUND

The gastrin gene is known to be expressed in all classes of bronchogenic carcinomas. Furthermore, high levels of gastrin have been reported in both the bronchoalveolar lavage (BAL) fluid and serum of patients with lung cancer. Based on these preliminary data a study was conducted to evaluate the usefulness of gastrin measurements in the diagnosis and staging of lung cancer.

METHODS

Thirty-five patients with lung cancer (26 non-small cell (NSCLC) and nine small cell (SCLC)) and 25 patients with chronic obstructive pulmonary disease underwent fibreoptic bronchoscopy and BAL. Gastrin levels were determined in both BAL fluid and the serum and compared with each other and with staging.

RESULTS

No difference was found between the gastrin levels in the BAL fluid or serum of the study groups. There was no correlation with the stage in NSCLC and no correlation was found between the gastrin levels in the serum and the BAL fluid. A significant difference was seen in gastrin levels in BAL fluid between extensive and limited SCLC (p < 0.05).

CONCLUSION

There is no evidence of clinical usefulness for gastrin measurements in lung cancer.

Integrin upregulation on sputum neutrophils in smokers with chronic airway obstruction

To determine the relationship between the expression of leukocyte-specific integrins in the airways and the airway obstruction in smokers, we analyzed hypertonic saline-induced sputum in 33 male subjects, age 64.7 +/- 0.5 yr (mean +/- SEM), with a smoking history of 12 to 94 pack-years, at the end of a 15-yr follow-up study. Average FEV1/VC ratio was 69 +/- 1% at the beginning of the study and 66 +/- 2% at the end of the follow-up period, and annual decline of FEV1 was 20 +/- 3 ml/yr. Fourteen individuals exhibited airway obstruction as assessed by a FEV1/VC ratio lower than 63.3%. Differential leukocyte count was performed on cytospin preparations and the expression of integrin alpha (CD11a, CD11b, CD11c) and beta (CD18) chains was assessed on granulocytes and mononuclear cells by immunocytology. The numbers of neutrophils expressing CD11b and CD18, but not CD11c or CD11a, were increased in the subjects with airway obstruction compared with those without airway obstruction. CD11b- and CD18-positive neutrophils were negatively correlated with FEV1/VC ratio (p < 0.01). No significant correlations were found between CD11a-, CD11b-, CD11c-, CD18-positive mononuclear cells and lung function measurements. In conclusion, our results suggest that leukocyte-specific integrin CD11b/CD18 expressed on sputum polymorphonuclear leukocytes represents a marker for the smokers who develop chronic airway obstruction.

The expression of adhesion molecules in cigarette smoke-induced airways obstruction

Cigarette smoking produces peripheral airway inflammation in all smokers, and chronic airways obstruction in approximately 20% of heavy smokers. The present study was designed to test the hypothesis that airways obstruction is related to changes in the expression of adhesion molecules involved in the recruitment of cells to sites of inflammation in the lung. Freshly resected lungs from heavy smokers with airways obstruction (n = 10) and from heavy smokers with normal lung function (n = 10) were collected in the operating room, inflated with optimal cutting temperature (OCT) medium and frozen over liquid nitrogen. Six micrometres thick cryostat sections cut from random samples of this tissue were stained, using immunohistochemistry, with monoclonal antibodies to the adhesion molecules on leucocytes: L-selectin, very late activation antigen-4 (VLA-4), CD11a/CD18, CD11b/CD18, CD11c/CD18; and on endothelial and epithelial surfaces: E-selectin, P-selectin, vascular cell adhesion molecule (VCAM-1), intercellular adhesion molecule (ICAM)-1 and ICAM-2 using the alkaline phosphatase anti-alkaline phosphatase (APAAP) technique. The slides were coded and the expression of each molecule scored by three observers using a semiquantitative grading system. Two inducible adhesion molecules, E-selectin on endothelium and CD11b on leucocytes, were also evaluated using quantitative morphometric analysis. The results showed a distribution of adhesion molecules that was consistent with the inflammatory response in the airways and parenchyma of all subjects but failed to show any differences between those with or without airways obstruction. We conclude that development of airways obstruction in heavy smokers cannot be explained by differences in the expression of adhesion molecules known to be involved in the control of cell traffic in the lung.

Systemic oxidative stress in asthma, COPD, and smokers

An imbalance between oxidants and antioxidants is proposed in smokers and in patients with airways diseases. We tested this hypothesis by measuring the Trolox equivalent antioxidant capacity (TEAC) of plasma and the levels of products of lipid peroxidation as indices of overall oxidative stress. The plasma TEAC was markedly reduced (0.66 +/- 0.07 mmol/L; mean +/- SEM; n = 11), with increased levels of lipid peroxidation products, in healthy chronic smokers as compared with healthy nonsmokers (1.31 +/- 0.10 mmol/L, n = 14, p < 0.001), an effect that was exaggerated in those who had smoked 1 h before the study. Plasma TEAC was also low in patients presenting with acute exacerbations of chronic obstructive pulmonary disease (COPD) (0.46 +/- 0.10 mmol/L, n = 20, p < 0.001) or asthma (0.61 +/- 0.05 mmol/L, n = 9, p < 0.01) with increases in plasma lipid peroxidation products. There was a negative correlation between superoxide anion release by stimulated neutrophils and plasma antioxidant capacity (r = -0.73, p < 0.001) in patients with acute exacerbations of COPD. The profound decrease in TEAC was associated with a decreased plasma protein sulfhydryl concentrations in acute exacerbations of COPD but not in smokers or in asthmatic subjects. Therefore smoking, acute exacerbations of COPD, and asthma are associated with a marked oxidant/antioxidant imbalance in the blood, associated with evidence of increased oxidative stress. The decreased antioxidant capacity in plasma may result from different mechanisms in these conditions.

Evaluation of plasma and urinary salbutamol levels in COPD

OBJECTIVE

To evaluate the use of trough plasma salbutamol and overnight urinary salbutamol excretion in the assessment of nebulised salbutamol delivery in patients with chronic obstructive pulmonary disease (COPD).

METHODS

Twenty in-patients with COPD receiving nebulised salbutamol, age 69.7 years, FEV1 38.1% predicted, were studied on two consecutive days, receiving four 2.5 mg doses of nebulised salbutamol on day 1 and four 5 mg doses of nebulised salbutamol on day 2, the first dose at 8.00 h the last dose at 22.00 h. Salbutamol delivery was assessed after the last dose by trough plasma salbutamol 8.00 h and overnight urinary excretion of salbutamol (22.00-8.00 h).

RESULTS

Levels of urinary salbutamol were detectable in all 20 patients at both doses, whereas for plasma salbutamol detectable levels were only found in 16/20 cases at the 2.5 mg dose and in all cases at the 5 mg dose. For overnight urinary salbutamol (microgram x 10 h-1 n = 20) the results were 141 for 2.5 mg and 249 for 5 mg. The dose ratio for urinary salbutamol between 2.5 mg and 5 mg doses was 1.83. Results for plasma salbutamol (ng/ml, n = 16) were 1.58 at 2.5 mg and 2.43 at 5 mg: dose ratio (geometric mean) 1.49.

CONCLUSION

Overnight urinary salbutamol provides a simple and effective measure of nebulised salbutamol delivery in patients with COPD, which would be suitable for studying nebuliser performance and compliance.

Increased exhalation of hydrogen peroxide in patients with stable and unstable chronic obstructive pulmonary disease

An imbalance between oxidative stress and antioxidative capacity is thought to play an important role in the development and progression of chronic obstructive pulmonary disease (COPD). To assess the lung oxidative status in patients with COPD, we studied whether exhaled hydrogen peroxide (H2O2) is increased in breath condensate of patients with stable COPD (n = 12, mean FEV1 51% pred) and in patients with exacerbated COPD (n = 19, actual FEV1 36% pred) compared with a healthy control group (n = 10, FEV1 108% pred). Expired breath condensate during 15 min of tidal breathing was collected by cooling. The concentration of H2O2 was measured spectrophotometrically by means of horse radish peroxidase-catalyzed oxidation of tetramethylbenzidine. Concentrations of H2O2 (mean +/- SEM) were significantly elevated at 0.205 +/- 0.054 microM in patients with stable COPD compared with 0.029 +/- 0.012 microM in the control group (p < 0.05) and were further increased to 0.600 +/- 0.075 microM in patients with acutely exacerbated COPD (p < 0.001 compared with patients with stable COPD). Patients with pulmonary infiltrates on chest radiograph showed similar values compared with patients without obvious infiltrates. These findings demonstrate that patients with stable COPD exhibit increased oxidant production in the airways and that oxidant production increases further during exacerbations.

The effects of theophylline on metabolic rate in chronic obstructive lung disease patients

OBJECTIVE

To study the effect of theophylline and an alternative bronchodilator, ipratropium, on resting energy expenditure (REE) and thermic effect of food (TEF).

DESIGN

5-week randomized, repeated measures, double-blind, cross-over design, comparing the effects of theophylline and ipratropium drug treatments on metabolic measurements made during a baseline period.

SETTING

Ambulatory Clinical Trials Center at University of California, San Diego.

SUBJECTS

14 patients at least 65 years old with a clinical diagnosis of chronic obstructive pulmonary disease.

MEASUREMENTS

Resting energy expenditure and thermic effect of food were measured by indirect calorimetry. Body composition was determined using bioimpedance.

RESULTS

Resting energy expenditure did not differ between baseline and either of the two drug treatments. In men, the thermic effect of food increased significantly during theophylline and ipratropium drug treatment periods (p < 0.03).

CONCLUSIONS

Theophylline or ipratropium does not appear to increase resting energy expenditure in patients with chronic obstructive lung disease. The elevated values for thermic effect of food in men need further study.

Evidence for a relation between metabolic derangements and increased levels of inflammatory mediators in a subgroup of patients with chronic obstructive pulmonary disease

BACKGROUND

An increase in resting energy expenditure (REE) commonly occurs in patients with chronic obstructive pulmonary disease (COPD), the cause of which is as yet unknown. The objective of this study was to assess the relationship between REE, acute phase proteins, and inflammatory mediators in patients with COPD.

METHODS

Thirty patients were studied and 26 healthy age-matched subjects served as controls. REE was measured by indirect calorimetry and adjusted for fat-free mass (FFM) by bioelectrical impedance analysis. Tumour necrosis factor alpha (TNF-alpha), soluble tumour necrosis receptor (sTNF-R)55 and sTNF-R75, interleukin (IL)-6, IL-8, and lipopolysaccharide binding protein (LBP) were measured by ELISA.

RESULTS

Fourteen patients had a normal REE and in 16 it was raised. The mean body mass index and fat mass were significantly lower in the latter but pulmonary function data were similar in the two groups. In the 30 patients with COPD the mean (SD) sTNF-R75 was 1.7 (1.0) ng/ml compared with 1.1 (0.4) ng/ml in the controls; C-reactive protein (CRP) was detectable (> 5 micrograms/ml) in eight patients compared with none of the control subjects, and LBP was 13.2 (7.7) micrograms/ml compared with 8.6 (3.1) micrograms/ml in the controls. The patients with a raised REE had increased mean levels of CRP compared with the patients with a normal REE (median 5.5 micrograms/ml (range 5-193) and < 5 micrograms/ml, respectively); the same was true for LBP (median 12.4 micrograms/ml (range 8.1-39.1) and 9.5 micrograms/ml (range 5.0-16.6), respectively), but sTNF-R55 and R75 and IL-8 were similar in the two groups. Of the 16 patients with a raised REE, the CRP level was increased in eight and normal in eight. In those with an increased level of CRP the FFM was decreased and LBP, IL-8, and sTNF-R55 and R75 were increased compared with those with normal CRP levels.

CONCLUSIONS

A subset of patients with COPD with an increased REE and decreased FFM have increased levels of acute phase reactant proteins and inflammatory cytokines in their serum; these phenomena may be causally related.

Comparison of the efficacy of a demand oxygen delivery system with continuous low flow oxygen in subjects with stable COPD and severe oxygen desaturation on walking

BACKGROUND

Provision of ambulatory oxygen using an intermittent pulsed flow regulated by a demand oxygen delivery system (DODS) greatly increases the limited supply time of standard portable gaseous cylinders. The efficacy of such a system has not previously been studied during submaximal exercise in subjects with severe chronic obstructive pulmonary disease (COPD) in whom desaturation is likely to be great and where usage is often most appropriate.

METHODS

Fifteen subjects with severe COPD and oxygen desaturation underwent six minute walk tests performed in random order to compare the efficacy of a demand oxygen delivery system (DODS) with continuous flow oxygen. Walk distance, breathlessness, oxygen saturation, resting time, and recovery time (objective and subjective) were recorded and compared for each walk.

RESULTS

Breathing continuous oxygen compared with baseline air breathing improved mean walk distance (295 m versus 271 m) and recovery time (47 seconds versus 112 seconds), whilst the lowest recorded saturation (81% versus 74%) and time desaturated below 90% (201 seconds versus 299 seconds) were reduced. When the DODS was compared with air breathing only the walk distance changed (283 m versus 271 m). A comparison of the DODS with continuous oxygen breathing showed the DODS to be less effective at oxygenating subjects with inferior lowest saturation (78% versus 81%), time spent below 90% (284 seconds versus 201 seconds), time to objective recovery (83 seconds versus 47 seconds), and walk distance (283 m versus 295 m).

CONCLUSIONS

Neither of the delivery systems was able to prevent desaturation in these subjects. The use of continuous flow oxygen, however, was accompanied by improvements in oxygenation, walk distance, and recovery time compared with air breathing. The DODS produced only a small increase in walk distance without elevation of oxygen saturation, but was inferior to continuous flow oxygen in most of the measured variables when compared directly.

[Physico-chemical properties of pulmonary surfactant after gastrectomy and cholecystectomy]

The frequency of broncho-pulmonary complication after the surgery in the organs of upper part of the abdominal cavity does not decrease, although the technique of operation and methods of anaesthesia have been improved. Disorders in the functioning of the surfactant systems of the lungs are evident in patients with chronic gastric and duodenal ulcers and calculous cholecystitis. Surgical intervention and anaesthesiologic measures promote further disturbance of the functional activity of lung surfactants. The most pronounced disorders in the functioning of the surfactant systems of the lungs were observed in patients with the broncho-pulmonary complications, commonly on the third day after the operation. This condition, is one of the main pathogenic causes of the manifestation of broncho-pulmonary complications in the post-operative period.

MR889, a neutrophil elastase inhibitor, in patients with chronic obstructive pulmonary disease: a double-blind, randomized, placebo-controlled clinical trial

We investigated whether MR889, a synthetic cyclic thiolic elastase inhibitor, administered for a period of 4 weeks to chronic obstructive pulmonary disease (COPD) patients, is well-tolerated, and whether it modifies biochemical indices of lung destruction. The study was a double-blind, randomized, placebo-controlled clinical trial in COPD patients. Thirty subjects were administered MR889 orally at a dose of 500 mg b.i.d. for 4 weeks, and 30 received placebo following the same schedule. In addition to safety parameters, MR889 efficacy was checked by a pretreatment/postreatment evaluation of levels of plasma elastin-derived peptides and urinary desmosine. There were no statistically significant differences between pretreatment and posttreatment efficacy parameter levels either in the control group or in the treated group. However, in a subset of treated patients with a short disease duration, the level of urinary desmosine dropped significantly with respect to pretreatment values (p = 0.004). We conclude that MR889 is safe to administer to COPD patients for a period of at least 4 weeks. During this time, MR889 does not modify biochemical markers of lung destruction in unselected COPD patients. Nevertheless, a subset of treated patients with fairly short disease duration showed a post-treatment reduction of desmosine urine levels, thus justifying the need for further studies to prove the efficacy of MR889 in modulating indices of lung destruction in COPD.

Metabolic phenotypes of retinoic acid and the risk of lung cancer

The metabolic activity of cytochrome P-450 enzymes has been associated with an increased risk of developing lung cancer. We found previously that all-trans retinoic acid is catabolized by these oxidative enzymes, and that an inhibitor of this system discriminated between two populations of lung cancer patients. We examined the association between this metabolic phenotype and the risk of lung cancer in 85 subjects. The area under the plasma concentration x time curve (AUC) was calculated after a single oral dose of all-trans retinoic acid (45 mg/m2). The mean AUC for patients who had either squamous or large cell carcinomas was significantly lower than that of patients with adenocarcinomas (P = 0.0001) or control subjects (P = 0.01). Individuals with an AUC < 250 ng x h/ml had a greater likelihood of having squamous or large cell carcinoma (odds ratio = 5.93). This study suggests that the "rapid" catabolism of all-trans retinoic acid is linked to an increased risk of squamous or large cell cancers of the lung.

Measurement of exhaled nitric oxide by three different techniques

The purpose of the study was to compare exhaled nitric oxide (NO) determined by three techniques. Ninety-one subjects performed a slow vital capacity maneuver: (1) through the mouth directly into a NO chemiluminescence analyzer (peak oral NO), (2) through the mouth into a collection bag (mean oral NO), and (3) through the nose into a collection bag (mean nasal NO). Peak oral NO was higher in patients with asthma (n = 18, 174.2 +/- 27.0 ppb), but lower in smokers (n = 36, 39.6 +/- 4.8 ppb) compared with nonsmoking control subjects (n = 23, 105.5 +/- 8.4 ppb, p < 0.05 both comparisons). Mean oral NO levels were significantly lower than peak oral NO levels (p < 0.05), but still higher in patients with asthma in comparison with nonsmoking healthy control subjects and asymptomatic smokers (27.2 +/- 3.5 versus 14.5 +/- 1.1 and 7.3 +/- 0.7 ppb, respectively, p < 0.05). In contrast, there was no significant difference in mean nasal NO levels between the three groups. Peak oral NO and mean oral NO levels correlated (r = 0.772, p < 0.0001). Determination of exhaled oral NO levels is qualitatively independent of the technique used, but nasal exhalation may affect NO determination in conditions associated with airway inflammation.

Interleukin 8 and granulocyte elastase alpha 1 proteinase inhibitor complex in the tracheobronchial aspirate of infants with chronic lung disease following inter-uterine infection

In order to elucidate the role of interleukin 8 (IL-8) in the development of chronic lung disease (CLD) of neonates with intra-uterine infection, serial and simultaneous measurements of the concentration of IL-8 and granulocyte elastase alpha 1 proteinase inhibitor complex (E-alpha 1 PI) in the tracheobronchial aspirate of low birth weight infants were conducted. Infants with a high serum IgM level at birth, and who subsequently developed CLD, showed significantly high concentrations of IL-8 and E-alpha 1 PI in the first 48 h. It seemed that IL-8 stimulated neutrophils to release neutrophil enzymes which, in turn, caused the lung tissue injury, resulting in the development of CLD following intra-uterine infection.

Clinical pharmacokinetics of meropenem after the first and tenth intramuscular administration

We investigated the pharmacokinetics of meropenem after the first and tenth i.m. administration in patients with respiratory tract infections. Ten patients (mean age 63.8 +/- 5.2 years) received meropenem 500 mg tds for at least ten doses, and plasma and urine antibiotic concentrations were determined by microbiological assay. After the first injection a mean peak plasma concentration of 7.93 +/- 1.29 mg/L was observed at 1 h. Trough levels at 8 h (0.29 +/- 0.16 mg/L) were detectable in five of ten treated patients. The mean terminal half-life was 1.08 +/- 0.2 h with an area under the curve (AUC) value of 23.8 +/- 4.59 mg/L.h, and a cumulative urinary recovery at 8 h of 48.43 +/- 3.12%. There was no evidence of change in the pharmacokinetics of meropenem after repeated i.m. administration, though the mean peak plasma concentration and AUC value were slightly increased. The accumulation ratio (assessed using AUC values) was 1.18 +/- 0.19 after multiple doses and was considered to be of little kinetic and clinical importance. Moreover, many of the trough concentrations of meropenem were below the limit of detection of the assay. After i.m. administration meropenem concentrations exceeded 0.5 mg/L for longer than previously described following i.v. infusion. No adverse events were reported.

Pulmonary pharmacology

This article reviews the basic principles of pharmacodynamics and pharmacokinetics, with a special emphasis on the pharmacologic considerations that must be taken into account when treating the patient with respiratory disease who is also pregnant or nursing the neonate. A description of the four classes of therapeutic agents used for COPD is given with a discussion of the scientific evidence for their safety during pregnancy. The understanding of asthma suggests that bronchodilators relieve the symptoms, while antiinflammatories suppress the disease. Direct administration to the target tissue by inhalation of the bronchodilators (beta-adrenoreceptor agonists and anticholinergics) and immunosuppressors (corticosteroids and cromolyn) leads to low systemic levels of these drugs, which reduces fetal drug exposure. Oral administration of beta-adrenoreceptor agonists, corticosteroids, and theophylline may be necessary to obtain sufficient maternal lung function and ensure adequate oxygenation of the fetus. This must be carefully weighed against the potential fetal and maternal risks involved with increased systemic levels of these drugs. A brief description of classes of drugs used for upper respiratory diseases (antihistamines, alpha-adrenergic agonists, corticosteroids, antitussives, and expectorants) and their safety during pregnancy is also given. There is concern that most alpha-adrenergic agonists increase blood pressure at therapeutic doses needed to relieve nasal congestion. Therefore, for pregnant patients requiring decongestants, opinion favors administration of pseudoephedrine, which has the most favorable therapeutic index, to reduce potential cardiovascular adverse reactions in the fetus. Intranasal administration of the newer corticosteroids, which have limited absorption, is useful for suppression of allergic rhinitis, while minimizing the risk of adverse reactions. The purpose of this article has been to provide pharmacologic/toxicologic information about commonly used respiratory drugs. This will to enable the clinician to make an educated decision regarding the choice of therapy for respiratory disorders to ensure that fetal and maternal outcomes are optimal.

Interleukin-8 in airway inflammation in patients with asthma and chronic obstructive pulmonary disease

We have investigated whether IL-8 is present in airway secretions from patients with asthma and chronic obstructive pulmonary disease (COPD) to obtain information on its possible role in airway inflammation in obstructive airways disease. In the bronchoalveolar lavage fluid (BALF) from 11 clinically stable patients with asthma the levels of IL-8 were increased compared to 10 healthy subjects (median: controls 21.5 pg/ml, asthma 244 pg/ml: p < 0.005). In the patients with asthma the levels of IL-8 correlated with the percentage neutrophils in the BALF (r = 0.81; p < 0.001) and with a parameter of the permeability of the respiratory membrane, the quotient (alpha 2-macroglobulin in BALF)/(alpha 2-macroglobulin in serum) (r = 0.66; p < 0.025). In the sputum sol phase of 9 patients with symptomatic asthma the levels of IL-8 were lower than in 9 patients with COPD (asthma: 6.4 ng/ml; COPD: 16.3 ng/ml; p < 0.02) and significantly correlated with those of neutrophilic myeloperoxidase (MPO; r = 0.85; p < 0.005). The increased levels of IL-8 in the airway secretions from both patients with asthma and COPD may be markers of an ongoing inflammatory process, which is more pronounced in patients with COPD. In patients with asthma the strong correlation between the levels of IL-8 and the percentage neutrophils and/or the levels of MPO points to a role of IL-8 in the recruitment and activation of neutrophils in the airway lumen.

Differences in interleukin-8 and tumor necrosis factor-alpha in induced sputum from patients with chronic obstructive pulmonary disease or asthma

Asthma and chronic obstructive pulmonary disease are characterized by chronic airway inflammation. Studies using bronchoalveolar lavage (BAL) have shown an increased proportion of eosinophils in the BAL fluid from asthmatics compared with that from normal subjects, whereas studies of chronic obstructive pulmonary disease (COPD) have shown increased numbers of neutrophils. Induced sputum allows sampling of respiratory tract secretions from patients and control subjects, providing a noninvasive method of studying airway secretions and allowing characterization of cells and measurement of soluble markers. We investigated whether induced sputum was a useful method of studying airway fluid from patients with moderate to severe COPD and whether it could be used to compare inflammation in this condition with that in asthma. An initial reproducibility study was undertaken. Sputum was induced twice in 13 patients with severe COPD at a 14-d interval. Total and differential cell counts were carried out and were found to be reproducible over this period. Sputum was then induced in 14 patients with COPD, 23 patients with asthma, 12 healthy cigarette smokers, and 16 normal nonsmoking control subjects. We found a significant increase in neutrophils and increased concentrations of tumor necrosis factor-alpha (TNF alpha) and interleukin-8 (IL-8) in the patients with COPD compared with the smoking and nonsmoking control subjects. Interleukin-8, but not TNF alpha, was significantly higher in the COPD group than in the asthmatic group. We conclude that the cytokines TNF alpha and IL-8 may be involved in the inflammation in COPD.

Oxidative capacity of the skeletal muscle and lactic acid kinetics during exercise in normal subjects and in patients with COPD

Early lactic acidosis during exercise and abnormal skeletal muscle function have been reported in chronic obstructive pulmonary disease (COPD) but a possible relationship between these two abnormalities has not been evaluated. The purpose of this study was to compare and correlate the increase in arterial lactic acid (La) during exercise and the oxidative capacity of the skeletal muscle in nine COPD patients (age = 62 +/- 5 yr, mean +/- SD, FEV1 40 +/- 9% of predicted) and in nine normal subjects of similar age (54 +/- 3 yr). Following a transcutaneous biopsy of the vastus laterialis, each subject performed a stepwise exercise test on an ergocycle up to his or her maximal capacity during which 5-breath averages of oxygen consumption (Vo2), and serial La concentration measurements were obtained. From the muscle biopsy specimen, the activity of two oxidative enzymes, citrate synthase (CS) and 3-hydroxyacyl CoA dehydrogenase (HADH), and of three glycolytic enzymes, lactate dehydrogenase, hexokinase, and phosphofructokinase were determined. The La/Vo2 relationship during exercise was fitted by an exponential function in the form La = a + bvo2, where be represents the shape of the relationship. The activity of the oxidative enzymes was significantly lower in COPD than in control subjects (22.8 +/- 3.3 versus 36.8 +/- 8.6 mumol/min/g muscle for CS, and 3.1 +/- 1.1 versus 5.5 +/- 1.4 mumol/min/g for HADH, p < 0.0005) and the increase in lactic acid was steeper in COPD (b = 4.3 +/- 2.0 versus 2.1 +/- 0.2 for normal subjects, p = 0.0005). A significant inverse relationship was found between CS, HADH, and b. No difference was found between the two groups for the glycolytic enzymes. We conclude that in COPD the increase in arterial La during exercise is excessive, the oxidative capacity of the skeletal muscle is reduced, and that these two results are interrelated.

Role of oxidants/antioxidants in smoking-induced lung diseases

An imbalance between oxidants and antioxidants has been considered in the pathogenesis of smoking-induced lung diseases, such as chronic obstructive pulmonary disease (COPD), particularly emphysema. Recent evidence indicates that increased neutrophil sequestration and activation occurs in the pulmonary microvasculature in smokers and in patients with COPD, with the potential to release reactive oxygen species (ROS). ROS generated by airspace phagocytes or inhaled directly from the environment also increase the oxidant burden and may contribute to the epithelial damage. Although much research has focused on the protease/antiprotease theory of the pathogenesis of emphysema, less attention has been paid to the role of ROS in this condition. The injurious effects of the increased oxidant burden in smokers and in patients with COPD are opposed by the lung antioxidant defences. Hence, determining the mechanisms regulating the antioxidant responses is critical to our understanding of the role of oxidants in the pathogenesis of smoking-induced lung disease and to devising future strategies for antioxidant therapy. In this article we have reviewed the evidence for the presence of an oxidant/antioxidant imbalance in smoking-induced lung disease and its relevance to therapy in these conditions.

Indirect calorimetry in critically ill patients: role of the clinical dietitian in interpreting results

Evaluation and interpretation of energy needs of critically ill patients require the expertise of clinical dietitians: Dietitians must be knowledgeable about the methods available to quantify energy needs and able to communicate effectively with physicians and nurses regarding nutritional requirements. Several prediction equations are available for calculating energy needs of critically ill patients. Indirect calorimetry is also used frequently to measure energy requirements in this patient population. This article defines when energy expenditure measured by indirect calorimetry may provide clinically useful information. Data obtained by indirect calorimetry must be interpreted carefully. Indirect calorimetry is based on the equations for oxidation of carbohydrate, protein, and fat. Errors in interpretation can be made when metabolic pathways other than oxidation dominate or when clinical conditions exist that affect carbon dioxide excretion from the lungs. Before incorporating data obtained from indirect calorimetry into a nutrition care plan, the clinical dietitian should carefully evaluate the following factors for a patient: clinical conditions when the measurement was made, desired weight loss or gain, tolerance to food or nutrition support, relationship between protein intake and energy need, and need for anabolism or growth. This article provides clinical examples illustrating how measured values compare with calculated values and recommendations for how to incorporate measured values into nutrition care plans.

[Free-radical processes in the pulmonary macrophages of patients with pulmonary tuberculosis]

Free radical processes in the alveolar and interstitial macrophages were compared for patients with different forms of tuberculosis, chronic nonspecific pulmonary diseases and cancer of the lungs. Alveolar macrophages were found to have more active free radical processes than interstitial macrophages. Chronic transformation of pulmonary tuberculosis results in activation of free radical processes in pulmonary macrophages. Differences in the value of alveolar macrophages chemiluminescence maximum and time of its appearance may facilitate differential diagnosis between tuberculosis, chronic nonspecific pulmonary diseases and cancer of the lungs.

The daily energy expenditure in stable chronic obstructive pulmonary disease

Resting energy expenditure is frequently increased in chronic obstructive pulmonary disease (COPD), but it is unknown if this hypermetabolism holds true over 24 h. The aim of this study was to measure the actual 24-h energy expenditure (24-h EE) in patients with stable COPD. Energy expenditure was measured by indirect calorimetry, using a metabolic chamber for 24-h EE and a canopy for basal metabolic rate (BMR). Physical activity was detected in the chamber by a radar system, and its duration was quantified. Two groups matched for age and height were studied: 16 male ambulatory patients with stable COPD and 12 male normal subjects. Body weight was 92 +/- 12% of ideal body weight in the group with COPD and 108 +/- 11% in the control group (p = 0.01). BMR was 120 +/- 7% of predicted in the group with COPD and 108 +/- 12% in the control group (p < 0.01). However, 24-h EE was similar in the two groups, amounting to 1,935 +/- 259 kcal in patients with COPD and 2,046 +/- 253 kcal in the control group (NS). This corresponded to 145% and 137% of predicted BMR, and to 121% and 126% of measured BMR in patients with COPD and the control group, respectively (NS). Patients were allowed to pursue their usual treatment within the chamber, and a positive correlation existed between 24-h EE and the daily dose of inhaled beta 2-agonists (p < 0.03). During daytime, physical activity was lower in patients with COPD. This study shows that patients with stable COPD are characterized by a normal daily energy expenditure in controlled conditions in spite of an increased basal metabolic rate. They appear to save energy by reducing their spontaneous level of physical activity.

Lack of an effect of nefazodone on the pharmacokinetics and pharmacodynamics of theophylline during concurrent administration in patients with chronic obstructive pulmonary disease

The effect of nefazodone on the pharmacokinetics and pharmacodynamics of theophylline was evaluated in a multiple-dose, randomized placebo-controlled, double-blind two-period crossover study in 13 patients who were undergoing theophylline therapy for chronic obstructive pulmonary disease. Two treatments were administered, each for 7 days: theophylline + 200 mg nefazodone twice daily (every 12h) and theophylline+matching nefazodone placebo capsule twice daily (every 12h). Mean peak and trough plasma concentrations of theophylline ranged from 13.1 to 14.5 micrograms ml-1 and 11.6 to 14.2 micrograms ml-1, respectively, at steady-state when theophylline was administered with or without concurrent dosing of nefazodone. Similarly, the mean area under the curve for theophylline ranged from 93.5 to 103 micrograms ml-1 h. When nefazodone and theophylline were co-administered, theophylline pharmacokinetic parameters did not significantly differ from those obtained when theophylline was administered with placebo. Forced expiratory volume in one second (FEV1) measurements taken when nefazodone or placebo were administered with theophylline did not differ from those obtained at baseline. The plasma concentration-time profiles for nefazodone and its metabolites were similar to those in other studies where nefazodone was administered alone. Since nefazodone did not affect the pharmacokinetics or the pharmacodynamics of theophylline, no change in theophylline dose should be needed as a consequence of nefazodone co-administration.

Population pharmacokinetics of theophylline. III. Premarketing study for a once-daily administered preparation

The population pharmacokinetic parameters for a once-daily administered preparation, Uniphyl were estimated from data collected in the premarketing clinical trial. Altogether, 2772 serum theophylline concentrations were obtained from 131 normal subjects and 306 patients suffering from chronic asthma or chronic obstructive pulmonary disease who participated in the phase I, II, and III clinical trials in Japan. The serum concentration profile was described by a linear one-compartment model with first-order absorption. The factors affecting the pharmacokinetics of this drug were examined by the likelihood ratio test using a nonlinear mixed effect model (NONMEM). The first-order absorption rate constant (Ka) for a 200-mg tablet in a fasting condition was obtained as 0.0773 (1/h), which was smaller than the elimination rate constant (0.168 1/h), indicating the flip-flop characteristic of this preparation. Food indigestion increased the Ka by 17% and the absorption lag time by 5-fold but did not affect the extent of absorption. The 400-mg tablet showed a Ka value 19%, smaller than the 200-mg tablet. Children not older than 15 years showed 58% longer absorption lag time. The inter-individual variability in Ka was 19%, suggesting small variability in the vivo release process. The total body clearance was related to hepatic function, smoking habits, and age. Furthermore, clearance decreased in association with the severity of illness. The findings obtained here are useful not only for the initial dosage adjustment for patients with a variety of backgrounds but also for doses individualization based on serum concentration monitoring with or without the Bayesian feedback method.

Plasma protein leakage and local secretion of proteins assessed in sputum in asthma and COPD. The effect of inhaled corticosteroids

Asthma and chronic obstructive pulmonary disease (COPD) are characterized by chronic airway inflammation with cell infiltration, increased plasma exudation and abnormal local secretion of proteins. We have analysed whether sputum differs in this respect between asthma (n = 9) and COPD (n = 9), and whether inflammatory markers in sputum are affected by treatment. In non-smoking asthma patients there was more plasma protein leakage, based on the relative coefficient of excretion Q alpha 2macroglobulin/QIgG (P = 0.03). There was less local secretion of sIgA and lactoferrin than in COPD (P < 0.05). Tryptase was slightly higher in sputum from asthma than from COPD (P < 0.05), whereas eosinophil cationic protein and myeloperoxidase were similar. After treatment with glucocorticosteroids, there was a reduction in the Q alpha 2macroglobulin/Qalbumin (P < 0.015), but no effect was seen on the levels of products from local cells. We conclude that sputum analysis is useful to study the local inflammatory process in asthma and COPD.