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Biomedical subjects

R A Stockley

Publications and source records attributed to R A Stockley.

At least 163 records · Page 9Linked to original sources
PubMed1986

Tissue inhibitor of metalloproteinases and collagenase inhibitory activity in lung secretions from patients with chronic obstructive bronchitis: effect of corticosteroid treatment.

Tissue inhibitor of metalloproteinases (TIMP) and collagenase inhibitory activity were measured in the sputum from nine subjects with chronic bronchitis before and five days after treatment with corticosteroid (oral prednisolone, 40 mg daily). The mean sputum TIMP concentrations for eight of the nine subjects increased from 3.1 (SD 0.87) micrograms/ml to 5.8 (1.9) micrograms/ml (2p less than 0.005). Similarly, the mean collagenase inhibitory activity in the sputum of eight of the nine subjects increased from 1.53 (1.1) U/ml to 2.69 (0.92) U/ml (2p less than 0.05). The TIMP concentrations in sputum exceeded the collagenase inhibitory activity, suggesting that a proportion of the TIMP was inactive. TIMP inactivity was not due to prior complexing with enzyme since the molecular weight of sputum TIMP (27,500) was similar to that described for the purified protein (28,000-28,500). Preliminary studies showed the presence of TIMP in bronchoalveolar lavage samples (range of six specimens 0.45 ng/ml-2.1 micrograms/ml, median 53 ng/ml). Collagenase inhibitory activity was detected in only two of these six lavage samples, suggesting that the TIMP was totally inactive in the other four samples. The significance of the metalloproteinase-inhibitor balance in the pathogenesis of chronic lung disease requires further study.

Enzyme Inhibitors↗
PubMed1986

Effect of short and long term antibiotic response on lung function in bronchiectasis.

In a study designed to show whether purulent bronchial secretions damage the lung reversibly or irreversibly, 18 patients with bronchiectasis underwent lung function tests before and after two weeks' antibiotic treatment to convert their sputum from purulent to mucoid, and 10 of them also after four months' treatment. After two weeks FEV1, forced vital capacity, vital capacity, functional residual capacity, and total lung capacity showed small but statistically significant (though not clinically useful) improvements. In the 10 patients studied after four months only FVC (of the four indices with significant improvements at two weeks in this group) was still higher than before treatment. These results contrast with those of an earlier study, in which large acute changes were found, perhaps because of differences in the patients studied. It is concluded that the absence of major changes in lung function points to physiological abnormality that is largely irreversible in these patients with chronic bronchial sepsis.

Adult↗
PubMed1986

Comparison of concentrations of two proteinase inhibitors, porcine pancreatic elastase inhibitory capacity, and cell profiles in sequential bronchoalveolar lavage samples.

Bronchoalveolar lavage is used to obtain cells and proteins from the lower respiratory tract for diagnosis and research. Uncertainity exists about which site in the lung is sampled by the lavage fluid and what effect different lavage volumes have on recovery of the constituents of lavage fluid. Dilution of alveolar lining fluid by lavage fluid is variable and results are usually expressed as protein ratios to surmount this problem. We have compared cell profiles and the concentrations of two proteinase inhibitors--the low molecular weight bronchial protease inhibitor antileucoprotease and alpha 1 proteinase inhibitor, together with alpha 1 proteinase inhibitor function and its relationship to the cell profile in sequential bronchoalveolar lavage fluid samples from patients undergoing bronchoscopy. There was no difference in total or differential cell counts or albumin or alpha 1 proteinase inhibitor concentrations between the first and second halves of the lavage. Both the concentration of antileucoprotease and the ratio of antileucoprotease to albumin were, however, lower in the second half of the lavage (2p less than 0.01 and 2p less than 0.05 respectively). There was no difference in the function of alpha 1 proteinase inhibitor (assessed by inhibition of porcine pancreatic elastase--PPE) between aliquots (0.28 mole PPE inhibited/mol alpha 1 proteinase inhibitor; range 0-1.19 for the first half and 0.37 mol PPE inhibited/mol alpha 1 proteinase inhibitor; range 0.10-0.80 for the second half). About 60-70% of alpha 1 proteinase inhibitor in each half of the lavage fluid was inactive as an inhibitor. The function of alpha 1 proteinase inhibitor did not differ between bronchitic smokers and ex-smokers. Alpha 1 proteinase inhibitor function was not related to the number of total white cells, macrophages, or neutrophils in the lavage fluid. Contamination of lavage by red blood cells was found to alter the concentration of alpha 1 proteinase inhibitor but not its function when aliquots with and without erythrocytes were compared. These results show that the only difference between the two halves of these lavage samples is in the amount of antileucoprotease present, suggesting that more proximal secretions are being harvested early in the lavage procedure. Much of the alpha 1 proteinase inhibitor present in the samples is functionally inactive, but this is not clearly related to any particular cell type or to smoking habits, and does not differ between different stages of the lavage procedure. Much of the alpha1 proteinase inhibitor present in the samples is functionally inactive, but this is not clearly related to any particular cell type or to smoking habits, and does not differ between different stages of the lavage procedure. Finally, the presence of erythrocytes probably does affect alpha(1) proteinase inhibitor concentration and such samples should be excluded from analysis.

Albumins↗
PubMed1986

Elastase inhibitors of sputum sol phase: variability, relationship to neutrophil elastase inhibition, and effect of corticosteroid treatment.

The concentrations of three known elastase inhibitors (alpha 1 proteinase inhibitor, antileucoprotease, and alpha 2 macroglobulin) have been determined in the sputum of six patients with obstructive bronchitis over five consecutive days. Antileucoprotease was the major inhibitor measured and potentially could provide more than 80% of the elastase inhibition, whereas the contribution of alpha 2 macroglobulin was less than 0.2%. Comparison with the inhibitory capacity of the secretions active against human neutrophil elastase showed that the inhibitors could account for only about half of the inhibition measured. This suggests the presence of a substantial amount of unrecognised inhibitor. Corticosteroid treatment in 10 patients reduced the mean alpha 1 proteinase inhibitor concentration (p less than 0.025) from 18.6 micrograms/ml (SD 22.5) to 9.8 (6.6). Antileucoprotease, however, increased (p less than 0.05) from 20.5 micrograms/ml (24.3) to 39.3 (23.4). These changes were associated with an increase in elastase inhibition (p less than 0.025) from 180 (160) micrograms elastase/ml secretion to 310 (130), suggesting a beneficial effect of steroid treatment on the antielastases in lung secretions.

Aged↗
PubMed1986

Short term response of patients with bronchiectasis to treatment with amoxycillin given in standard or high doses orally or by inhalation.

The effect of three amoxycillin treatment regimens on purulent secretions of patients with bronchiectasis has been studied. On the basis of information recorded on a diary card the patients were divided into three groups, according to the usual nature of their secretions: seven who produced mucoid sputum, which occasionally became purulent; seven whose secretions were usually mucopurulent but occasionally purulent; and 19 whose secretions were persistently purulent. Treatment with capsules of amoxycillin in a dosage of 250 mg three times a day resulted in clearance of purulent secretions in patients of the mucoid group when they were treated for a clinical exacerbation. The sputum remained clear in these patients for long periods before a further exacerbation (median 6 1/2, range 1-11 months). The mucopurulent-purulent group also responded to this dosage but sputum purulence returned more rapidly (median 9, range 4-31 days). Only three of the 19 (17%) patients with persistently purulent secretions showed a macroscopic response to this dosage, whereas seven (60%) of 12 patients who received the higher dosage (3 g sachets twice a day) responded. Among the failures, some responded to nebulised amoxycillin, suggesting that higher levels of amoxycillin in secretions are required in these patients. Macroscopic clearance of purulent secretions was finally achieved in most of the patients studied. The response was not always predictable from the results of sputum culture. Clearance of secretions by antibiotics was also identified by the patients, using a diary card score. Improvements in well being and in symptoms were noticed even in the group who usually produced mucopurulent and purulent secretions even though they appeared to be clinically stable before treatment.

Administration, Oral↗
PubMed1986

The effect of reducing agents on proteolytic enzymes and oxidation of alpha 1-proteinase inhibitor.

We have studied the effect of the mucolytic agent N-acetylcysteine and dithiothreitol on the oxidation of alpha 1-PI by hydrogen peroxide, and their effect on porcine pancreatic elastase and leukocyte elastase. In addition, the effect of S-(carboxymethyl)cysteine (= carbocisteine, a mucolytic agent which does not have reducing properties) was studied in vitro and in patients with chronic obstructive bronchitis. Following addition of 59.6mM N-acetylcysteine, the amidolytic activity of leukocyte elastase was decreased by 55.3% and that of porcine pancreatic elastase by 57.0%. Dithiothreitol (5.7 mM) caused the loss of 97.4% and 67.6% of amidolytic activity of leukocyte elastase and porcine pancreatic elastase respectively whereas S-(carboxymethyl)cysteine had no effect. Similar results were found for the effect on elastolytic activity. Oxidation of alpha 1-PI by 8.6mM H2O2 resulted in partial loss of inhibitory function (mean 68.7% activity of native alpha 1-PI). N-Acetylcysteine and dithiothreitol prevented oxidation of alpha 1-PI when pre-incubated with H2O2 or incubated with alpha 1-PI and H2O2 simultaneously (94.5% and 94.4% activity of native alpha 1-PI for N-acetylcysteine; 78.3% and 87.6% activity for dithiothreitol - p less than 0.025). S-(Carboxymethyl)cysteine, when pre-incubated with H2O2 or incubated concurrently with alpha 1-PI and H2O2, caused a further decrease in the porcine pancreatic elastase inhibitory capacity of alpha 1-PI (53.1% and 63.0% respectively - p less than 0.025). None of the agents reversed oxidative inactivation once it had occurred. S-(Carboxymethyl)cysteine had no effect on alpha 1-PI function in sputum at the dose used.

Acetylcysteine↗
PubMed1986

The effect of catalase and methionine-S-oxide reductase on oxidised alpha 1-proteinase inhibitor.

Oxidative damage to alpha 1-proteinase inhibitor (alpha 1-PI) may be important in the pathogenesis of emphysema. We have studied the ability of 2 enzymes (catalase and methionine-S-oxide reductase) to prevent and reverse oxidation of alpha 1-PI by hydrogen peroxide. Pre-incubation of catalase with H2O2 protected alpha 1-PI from oxidation, but the enzyme could not reverse prior oxidation of alpha 1-PI. In contrast, methionine-S-oxide reductase fully restored activity to H2O2-oxidised alpha 1-PI. Sputum sol-phase from smokers and non-smokers contained alpha 1-PI that was only about 30% active. Functional activity increased in both smokers (p less than 0.025) and non-smokers (p less than 0.05) approximately 2-fold following incubation with the reductase. Western blotting of the samples showed that about 20% of the alpha 1-PI was present as an enzyme-inhibitor complex and 20% was proteolytically cleaved. These observations suggest proteolysis, complexing with enzyme and oxidation are mechanisms of inactivation of alpha 1-PI in lung secretions.

Blood Proteins↗
PubMed1985

Concentration of bronchoalveolar lavage fluid by ultrafiltration: evidence of differential protein loss and functional inactivation of proteinase inhibitors.

Bronchoalveolar lavage samples were concentrated using positive-pressure ultrafiltration. The starting material, concentrates, and eluates were assayed for immunoglobulin A (IgA), albumin (Alb), alpha 1-proteinase inhibitor (alpha 1-PI), antileukoprotease (ALP), and total leukocyte elastase inhibitory capacity (LEIC). No enzyme inhibitory capacity or protein was detected in membrane eluates, confirming the selectivity of the membrane used (Mr cutoff 2000 or 500). However, the concentrated lavages showed a generated loss of protein. The proportion of each protein recovered using the 500 Mr cutoff membrane was: IgA, 50.6% (+/- 15%); albumin, 43% (+/- 8.4); alpha 1-PI, 53.6 (+/- 17.3); ALP, 43% (+/- 2.1); and LEIC, 18.4% (+/- 2.6). Similar results were obtained with the 200 Mr cutoff membrane. The alpha 1-PI/Alb and the IgA/alb ratios were higher (2P less than 0.05) in the concentrates than in the starting material, suggesting differential protein loss. Protein losses were due to binding to the membrane since the wash with saline solution improved recoveries: IgA, 80%; Alb, 56%; alpha 1-PI, 64%; ALP, 66%; LEIC, 29%. Concentration of bronchoalveolar lavage fluids therefore resulted in substantial differential losses in elastase inhibitory capacity and protein concentrations, suggesting analysis of these fluids should be performed on unconcentrated samples.

Body Fluids↗
PubMed1985

Cathepsin B-like cysteine proteinase activity in sputum and bronchoalveolar lavage samples: relationship to inflammatory cells and effects of corticosteroids and antibiotic treatment.

Cathepsin B-like activity was measured in lung secretions by using the fluorimetric substrate benzyloxycarbonyl-L-arginine-L-arginine-4-methyl-7-coumarylamide (Z-Arg-Arg-MEC). The enzyme had a pH optimum of approximately 5.5 and had the characteristics of an alkaline-stable cysteine proteinase. Enzyme activity in the sputum from ten subjects with chronic bronchitis was significantly reduced after 5 days' treatment with prednisolone. Seven patients with bronchiectasis were studied before and after 14 days' treatment with amoxycillin. Cysteine proteinase activity was significantly reduced after 7 days' therapy, in parallel with a change in sputum quality from purulent to mucoid. One week after cessation of treatment enzyme levels were again increased but were still significantly lower than pretreatment values. Enzyme activity in 21 bronchoalveolar lavage specimens correlated significantly with neutrophil counts but not with macrophage counts. Cysteine proteinase activity in lung secretions resembles that of cathepsin B but is alkaline-stable, suggesting it is a distinct enzyme. The levels of cysteine proteinase in lung secretions appear to be related to the presence of inflammation or infection.

Aged↗
PubMed1985

Nebulized amoxicillin in chronic purulent bronchiectasis.

Nebulized amoxicillin (500 mg twice a day) was given for four months to six patients with bronchiectasis. The patients had continually produced purulent secretions, which had failed to clear (purulent to mucoid) when amoxicillin was given orally (3 gm twice a day). All patients found the nebulization technique acceptable, and no acute effect on lung function was seen. There were significant reductions in sputum purulence (P less than 0.025) and volume (P less than 0.05) and a mean (+/- SD) increase in peak expired flow rate (P less than 0.05) from 230.5 +/- 79.2 L/min to 255 +/- 90.1 L/min. These improvements occurred despite the fact that apparently resistant bacteria were cultured. No adverse effects were noted. The response to nebulized amoxicillin after failure with the same drug given orally suggests that local concentrations of antibiotic in the lungs of these patients is important.

Adult↗
PubMed1984

The effect of leucocyte elastase on the immunoelectrophoretic behaviour of alpha 1-antitrypsin.

Two-dimensional immunoelectrophoresis and conventional sodium dodecyl sulphate-polyacrylamide gel electrophoresis was performed on various mixtures of purified alpha 1-antitrypsin (alpha 1AT) and leucocyte elastase (LE). The results confirm that alpha 1AT inhibits LE by the formation of enzyme-inhibitor complexes demonstrable by both techniques. The complexes break down with time and are not affected by pH in the presence of excess alpha 1AT. However, the breakdown is more rapid in the presence of excess enzyme only at pH values where LE remains active. The resultant products of the complex breakdown include inactivated LE and alpha 1AT that has undergone limited proteolysis. It is concluded that the presence or absence of alpha 1AT-enzyme complexes as demonstrated by two-dimensional immunoelectrophoresis must be interpreted with caution when studying alpha 1AT function in lung secretions. The absence of such complexes does not mean that previous interaction with enzyme has not occurred, thereby accounting for a reduction in alpha 1AT inhibitory capacity.

Electrophoresis, Polyacrylamide Gel↗
PubMed1984

Elastolytic activity of sputum and its relation to purulence and to lung function in patients with bronchiectasis.

Sputum samples from 34 patients with bronchiectasis were assessed subjectively and the results related to objective measurements of elastase activity and albumin content. The results suggest that the macroscopic appearance of the sample is related to the elastase content. 88.7% of the purulent samples but none of the mucoid samples showing elastase activity. The macroscopic appearance was also associated with changes in protein transudation into the secretions. The median sputum: serum albumin concentration ratio was 0.71 X 10(-2) (range 0.22-4.7) in the mucoid samples but was greater in purulent samples (p less than 0.005), with a median value of 1.52 X 10(-2) (range 0.55-12.72), suggesting that purulence in the stable state was associated with low grade pulmonary inflammation or epithelial damage or both. Abnormalities of air flow were found in 24 of the patients (70.6%) but there was a significantly higher ratio of residual volume to total lung capacity (p less than 0.025) in patients who regularly produced purulent sputum (mean (SD) RV/TLC 44.4% (9.0%] than in those with mucoid or mucopurulent secretions (38.0% (9.9%]. A similar difference was found between those who produced elastase positive secretions and those who produced elastase negative ones.

Adult↗
PubMed1984

Effect of antibiotic treatment on sputum elastase in bronchiectatic outpatients in a stable clinical state.

Broad spectrum antibiotic treatment was given on 21 occasions to 15 patients with bronchiectasis who regularly produced purulent, elastase positive secretions. Although the results showed that sputum clearing--that is, changing from purulent to mucoid--largely depended on the pathogenic organism isolated, this was not exclusively the case and in some cases sputum growing sensitive organisms failed to clear whereas clearing occurred in other samples containing resistant organisms or no obvious pathogens. Clearing of sputum was achieved eventually in 12 of the patients and this was associated with the disappearance of elastase activity, although it returned in 10 patients within one week of stopping treatment. There was no change in sputum elastase where the sputum failed to clear. The clearance of elastase activity was associated with a decrease in protein transudation into the lung secretions. The sputum:serum albumin concentration ratio fell (p less than 0.005) from a mean (SD) of 2.32 (1.56) X 10(-2) in these 12 patients before treatment to 1.09 (0.40) X 10(-2) within the first week of treatment, but rose again to 2.07 (1.29) X 10(-2) within one week of stopping treatment. The results suggest that antibiotic treatment when patients are in a stable state may have a beneficial effect on the pathogenic nature of lung secretions and inflammation within the lung.

Adult↗
PubMed1984

Inhibitory capacity of alpha 1 antitrypsin in lung secretions: variability and the effect of drugs.

The inhibitory function of alpha 1 antitrypsin (alpha 1AT) has been studied in the lung secretions of 31 patients with chronic obstructive bronchitis. The inhibitory capacity for a single sample showed a wide range (median 0.13 micrograms porcine pancreatic elastase (PPE) inhibited per microgram alpha 1 antitrypsin; range 0-0.55 micrograms), and all but five of 86 samples studied were capable of inhibiting some porcine pancreatic elastase. No sample showed free elastase activity, however. The inhibitory capacity, studied in six patients over five consecutive days, varied daily within the same individual (coefficient of variation 9.0-108.9%). Corticosteroid treatment (40 mg prednisone daily) increased the inhibitory capacity of sputum alpha 1 antitrypsin in 10 patients (2p less than 0.05) from a median value of 0.13 micrograms PPE inhibited per microgram alpha 1AT (range 0.06-0.36) before treatment to 0.22 micrograms PPE inhibited per microgram alpha 1AT (range 0.09-0.65) after treatment. The inhibitory capacity of sputum was higher than in the corresponding bronchoalveolar lavage sample from the same patient (2p less than 0.05; n = 10). The median value for sputum was 0.22 micrograms PPE inhibited per microgram alpha 1AT (range 0-0.55) and the value for lavage fluid was 0.07 micrograms PPE inhibited per microgram alpha 1AT (range 0-0.27).

Aged↗