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Biomedical subjects

D Burnett

Publications and source records attributed to D Burnett.

At least 127 records · Page 7Linked to original sources
PubMed1986

Cathepsin B synthesis by the HL60 promyelocytic cell line: effects of stimulating agents and anti-inflammatory compounds.

Cathepsin B synthesis by the human HL60 promyelocyte cell line was investigated by immunohistochemistry and by the assay of the enzyme in cell lysates using a fluorimetric substrate. HL60 cells were shown to produce cathepsin B in response to treatment with 12-O-tetradecanoylphorbol 13-acetate (TPA). Intracellular levels of cathepsin B and immunohistochemical staining of the enzyme were related to time in culture with increasing concentrations of TPA from 1 nmol/1 to 8.0 nmol/1. Synthesis of cathepsin B was associated with TPA-induced phagocytic activity of cells in culture, expression of alpha-naphthyl acetate esterase and reduced cell division. Cathepsin B production was, therefore, related to differentiation of the HL60 promyelocytes into mature macrophage-like cells. Cathepsin B activity in HL60 cell lysates was significantly increased by incubation of the cells with 10 micrograms/ml endotoxin (lipopolysaccharide) from Escherichia coli, but not carrageenan. The production of cathepsin B by TPA-induced HL60 cells was significantly reduced by 0.25 mumol/1 dexamethasone and the non-steroidal anti-inflammatory compound 4-(6-methoxy-2-naphthyl)-butan-2-one but not by indomethacin. The HL60 promyelocytic cell line is a useful model for the study of factors affecting proteinase synthesis by human mononuclear phagocytes.

Anti-Inflammatory Agents↗
PubMed1986

Presence of two distinct acinar cell populations in human pancreas based on their antigenicity.

The immunohistochemical localization of ABH- and Lewis (Le)-related blood group antigens, including CA 19-9, a sialylated Lea antigen, was examined using monoclonal antibodies (MoAbs) in 18 normal human pancreases and compared with ABH blood group antigenicity of the individuals. Acinar cells expressed ABH, Leb, Ley, and in some cases, Lex antigen in various proportions, but not Lea and CA 19-9. The reactivity of Leb and Ley was similar with regard to cellular localization and specificity. In all specimens but one, the distribution of Leb (and Ley) and H antigens on the one hand, and of A or B antigens on the other, showed a reciprocal relationship, in that one group of acini expressed Leb (and Ley) and H antigens, but lacked any A or B antigens (type 1 acinar cell); another group of acinar cells had A or B antigens, but expressed neither Leb (Ley) or H antigens (type 2 acinar cell). In ductal cells, four of eight individuals with blood group A, two of three with blood group B, and five of six with blood group O expressed the appropriate antigen, while the remainder did not. Lea antigen was expressed primarily by centroacinar and terminal ductular and ductal cells of medium-sized ducts of all specimens, whereas Leb was present in the cells of small and large ducts in all but four cases. The reactivity of ductal and ductular cells to Lex was negative, except for one case. MoAb-Ley and MoAb 19-9 reacted only with a few ductal cells in six (33%) and 12 cases (67%), respectively. There was no relationship in the expression of Le-related antigens between acinar and ductal/ductular cells; nor were there any sex difference with regard to the binding patterns of any antibodies. However, age appeared to influence the reactivity of some antibodies with acinar cells. Islet cells did not react with any of the antibodies. The results indicate that, although the antigenicity of epithelial cells can be affected by the host blood group types, there might be several regulatory systems for expression of blood group antigens in a cell-specific pattern.

Adolescent↗
PubMed1986

Effect of cigarette smoking, pulmonary inflammation, and lung disease on concentrations of carcinoembryonic antigen in serum and secretions.

A specific radioimmunoassay for carcinoembryonic antigen was used to investigate aspects of its measurement in lung disease. The results confirm that serum carcinoembryonic antigen concentrations are higher in healthy smokers and patients with chronic obstructive bronchitis than in healthy non smokers (p less than 0.01). Corticosteroid treatment reduced the concentration in nine patients with bronchitis (p less than 0.05). Other inflammatory lung diseases (bronchiectasis, pneumonia, fibrosing alveolitis) are not associated with a raised serum carcinoembryonic antigen concentration. The sputum concentrations were about 100 times those found in serum and there was a positive correlation (r = 0.611 2p less than 0.01) between the concentrations in sputum and serum in patients with bronchitis. No preferential rise in sputum concentration was found in current smokers or patients with lung carcinoma (n = 16). A higher ratio of carcinoembryonic antigen to albumin concentration (p less than 0.05) was, however, found in lavage fluid obtained from the tumour site than in fluid from "normal" lung in the same patients, suggesting an increase in carcinoembryonic antigen secretion in the vicinity of the tumour. Despite this "local" effect the sputum concentration does not, however, appear to be a useful marker of lung carcinoma and the measurement could not be used as a screening test.

Bronchitis↗
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

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

Regional quality assessment of pH and blood gas analysers.

The performance of 41 pH and blood gas analysers in 20 hospitals was assessed using commercially available blood gas ampoules provided by seven manufacturers. The stability of the material and the effect of ambient temperature on Po2 was assessed. The overall mean values were outside the manufacturers' assigned values on eight out of 64 values. Using IL413 analysers as a basis for comparison, significant differences were found for Pco2 on ABL1, Corning 168 and 178 analysers and for Po2 on ABL1 and 2 and Corning 178. No significant differences were found for pH. Poor performers were identified in terms of imprecision. Analysers within or associated with clinical biochemistry departments gave better performance than those outside the laboratory. The five analysers that provided insufficient data for inclusion in the study were all situated outside the laboratory. Analysers from different manufacturers performed equally well provided they were used regularly and in accordance with manufacturers' instructions.

Blood Gas Analysis↗
PubMed1986

Acceptance of values assigned to serum-based calibration materials.

A questionnaire sent to laboratories in the UK and Ireland elicited information on acceptance or otherwise of values assigned to serum-based calibration materials for 14 analytes. Overall, 33% of assigned values were changed by users. The reasons for change, together with the degree of magnitude and direction of change, were studied for each analyte. Unidirectional changes made to assigned values were related to particular batches and manufacturers. Detailed information is presented for protein (Beckman RIIC Ltd.) on Astras, and sodium, bicarbonate and bilirubin on SMACs and SMAs (Technicon Instrument Co. Ltd.).

Blood Chemical Analysis↗
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

Detection of antithrombin III microheterogeneity.

Antithrombin III microheterogeneity was investigated by isoelectric focusing and immunofixation in healthy individuals and in patients with clinical conditions in which antithrombin III is known to vary (liver disease, nephrotic syndrome, after surgery and anticoagulant therapy). In normal plasma microheterogeneity was present with ten bands of varying intensity being visible in a pI range from 5.0-5.7. One variant was observed which was not associated with a clinical disorder. Low concentrations of antithrombin III were detected in some patients with liver disease, nephrotic syndrome and those on anticoagulant therapy and these demonstrated a decrease of intensity in all bands. Alterations in microheterogeneity were seen in patients tested after surgery and those with nephrotic syndrome. This indicates that changes in the subpopulations of antithrombin III can occur and may be relevant to clinical abnormalities.

Anticoagulants↗
PubMed1985

The distribution of cathepsin B in human tissues.

Cathepsin B is a lysosomal enzyme of importance in many physiological and pathological processes. Its distribution in human tissues was studied by an indirect immunoperoxidase method. Cathepsin B was demonstrated in macrophages, hepatocytes, renal tubules, gastrointestinal epithelium and fibroblasts, confirming previous studies. It was demonstrated for the first time by immunohistology in several other tissues, especially stratified squamous epithelium, transitional epithelium, salivary glands, pancreas, central and peripheral neuronal cell bodies, trophoblast and all endocrine organs. Widespread distribution of cathepsin B has been postulated several times but this is the fullest evidence that the enzyme indeed occurs in many organs. In pathology cathepsin B has so far been thought to be involved in demyelination, emphysema, rheumatoid arthritis and neoplastic infiltration.

Cardiovascular System↗
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

Lectin binding affinities of induced pancreatic lesions in the hamster model.

We examined the binding pattern of nine lectins to N-nitrosobis(2-oxopropyl)amine (BOP)-induced pancreatic lesions in Syrian hamsters. These lectins were Arachis hypogaea (PNA), Dolichos biflorus (DBA), Griffonia simplicifolia I (GS-I), Helix aspersa (HAA), Helix pomatia (HPA), Sophora japonica (SJA), Ricinus communis I (RCA-I), Triticum vulgaris (WGA) and Ulex europaeus I (UEA-I). All of the lectins reacted in untreated control hamsters to varying intensities with cytoplasmic components of acinar cells. GS-I, HPA, RCA-I and UEA-I bound to the basolateral surface and PNA, HAA and HPA to the luminal surface of these cells. All but GS-I, RCA-I and UEA-I stained the cytoplasm of islet cells diffusely. In untreated control hamsters, some ductal cells bound PNA, HAA and RCA-I, whereas these cells reacted negatively to the remaining six lectins. Ductular cells did not bind any of the nine lectins. Hyperplastic ductal cells in untreated hamsters were reactive with all nine lectins; however the intensity of the reactivity, cellular localization and extent differed for each lectin. In carcinogen-treated hamsters, the binding pattern of the lectins to acinar and islet cells did not differ significantly from that in untreated hamsters, whereas cells of induced ductal and ductular lesions bound each of the lectins in different patterns and intensities. The reaction of UEA-I to induced lesions was most consistent, specific and strong, thereby indicating the presence of L-fucose in glycoproteins produced by altered cells. Although the binding affinity of the lectins to induced hyperplastic lesions differed in both a quantitative and qualitative fashion, all dysplastic and malignant lesions were reactive to each lectin. This result indicates a heterogeneity in the carbohydrate structure of the glycoproteins produced by pancreatic cells during carcinogenicity.

Animals↗
PubMed1985

Immunohistochemical localization of cathepsin G in human tissues.

An antiserum to human cathepsin G has been raised in sheep and its reactivity with human tissues has been tested. The indirect immunoperoxidase staining sequence was employed and was applied to routinely processed paraffin sections. Mature granulocytes, especially those of the neutrophil variety, were intensely and consistently stained. Activity was not observed in other cell or tissue types. Many of the cells of acute and chronic myeloid leukemia were strongly stained, in contrast to those of acute lymphoblastic or chronic lymphocytic leukemias. The results of the technique are compared with those described with staining for muramidase (lysozyme), alpha 1-antitrypsin, leukocyte elastase, and naphthol-AS-D-chloroacetate esterase, and with certain monoclonal antisera directed against granulocyte determinants.

Cathepsin G↗