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Biomedical subjects

A Gillissen

Publications and source records attributed to A Gillissen.

At least 19 recordsLinked to original sources
PubMed1997

Oxidant scavenger function of ambroxol in vitro: a comparison with N-acetylcysteine.

Highly reactive oxygen metabolites play an important role in inflammatory processes in the lung. Ambroxol (2-amino-3,5-dibromo-N-[trans-4- hydroxycyclohexyl]benzylamine) has been shown to reduce oxidant-mediated cell damage. However, the mechanism of this effect remains unclear. In order to evaluate oxidant scavenger function increasing concentrations of ambroxol (0-10(-3) mol/l) were compared with equimolar concentrations of N-acetylcysteine (NAC) and glutathione (GSH) in vitro to reduce OH. (hydroxyl radical), HOC1 (hypochlorous acid), O-2 (superoxide anion) and H2O2 (hydrogen peroxide). OH. was measured spectrophotometrically (deoxyribose assay); O-2 (xanthine/x-oxidase), H2O2 and HOC1 (HOC1/OC1-) were determined by chemiluminescence. Ambroxol, NAC and reduced GSH scavenged OH. significantly at 10(-3) mol/l, while HOC1 was inhibited at concentrations > or = 10(-4) mol/l completely (P < 0.01). NAC and GSH had no anti-O-2 function, while ambroxol (10(-4) mol/l) reduced O-2 by 14.3 +/- 6.7%. In contrast, GSH and NAC scavenged H2O2 at > 10(-6) mol/l (P < 0.01), while ambroxol had no anti-H2O2 effect. Our data demonstrate direct oxidant-reducing capabilities of ambroxol, which may be directly related to the aromatic moiety of the molecule. However, high concentrations (micromolar concentrations) are needed. Due to differences in direct oxidant scavenger function, a combination of ambroxol and NAC could be beneficial in antioxidant therapy.

Acetylcysteine↗
PubMed1997

Antioxidant function of ambroxol in mononuclear and polymorphonuclear cells in vitro.

This study quantifies the antioxidant function of ambroxol (2-amino-3,5-dibromo-N-[trans-4-hydroxycyclohexyl]benzylamine) in vitro. Polymorphonuclear cells (PMN) and mononuclear cells were isolated from the blood of healthy volunteers (n = 46) to determine reactive oxygen species (ROS) by luminol-enhanced chemiluminescence. Ambroxol or the controls N-acetylcysteine (NAC), nacystelyn (NAL), glutathione (GSH), superoxide dismutase (SOD), catalase, and the combination of SOD/catalase were incubated for 1 or 2 h with zymosan-activated cells in vitro using concentrations ranging from 10(-6) to 10(-3) mol/liter. Reduction of ROS-mediated luminescence was similar within the cell types. Ambroxol (10(-4) mol/liter) reduced ROS about 75% (1-h incubation) and 98% (2-h incubation), respectively (p < 0.001). SOD and SOD/catalase, but not the H2O2-catalyzing substances (NAC, NAL, GSH, and catalase), reduced cellular ROS. This indicates that inflammatory cells predominantly generate O2-, which can be scavenged by ambroxol. The antioxidant function of ambroxol with increasing incubation time suggests additional cellular antiinflammatory properties of this substance. Our results indicate that good antioxidant function of ambroxol is related mainly to direct scavenger function of reactive oxygen metabolites such as O2-. However, an antioxidative effect of ambroxol may also be associated with the reduction of prooxidative metabolism in inflammatory cells. Concluding from this observation, and because of the well known high affinity of ambroxol for lung tissue, ambroxol may be an alternative in antioxidant augmentation therapy, particularly in pulmonary diseases characterized by an overburden of toxic oxygen metabolites.

Acetylcysteine↗
PubMed1997

Nacystelyn, a novel lysine salt of N-acetylcysteine, to augment cellular antioxidant defence in vitro.

Nacystelyn (NAL), a recently-developed lysine salt of N-acetylcysteine (NAC), and NAG, both known to have excellent mucolytic capabilities, were tested for their ability to enhance cellular antioxidant defence mechanisms. To accomplish this, both drugs were tested in vitro for their capacity: (1) to inhibit O2- and H2O2 in cell-free assay systems; (2) to reduce O2- and H2O2 released by polymorphonuclear leukocytes (PMN); and (3) for their cellular glutathione (GSH) precursor effect. In comparison with GSH, NAL and NAC inhibited H2O2, but not O2-, in cell-free, in vitro test systems in a similar manner. The anti-H2O2 effect of these drugs was as potent as that of GSH, an important antioxidant in mammalian cells. To enhance cellular GSH levels, increasing concentrations (0-2 x 10(-4) mol l-1) of both substances were added to a transformed alveolar cell line (A549 cells). After NAC administration (2 x 10(-4) mol l-1), total intracellular GSH (GSH + 2GSSG) levels reached 4.5 +/- 1.1 x 10(-6) mol per 10(6) cells, whereas NAL increased GSH to 8.3 +/- 1.6 x 10(-6) mol per 10(6) cells. NAC and NAL administration also induced extracellular GSH secretion; about two-fold (NAC), and 1.5-fold (NAL), respectively. The GSH precursor potency of cystine was about two-fold higher than that of NAL and NAC, indicating that the deacetylation process of NAL and NAC slows the ability of both drugs to induce cellular glut production and secretion. Buthionine-sulphoximine, which is an inhibitor of GSH synthetase, blocked the cellular GSH precursor effect of all substances. In addition, these data demonstrate that NAC and NAL reduce H2O2 released by freshly-isolated cultured blood PMN from smokers with chronic obstructive pulmonary disease (COPD) (n = 10) in a similar manner (about 45% reduction of H2O2 activity by NAC or NAL at 4 x 10(-6) mol l-1). In accordance with the results obtained from cell-free, in vitro assays, O2- released by PMN was not affected. Ambroxol (concentrations: 10(-9)-10(-3) mol l-1) did not reduce activity levels of H2O2 and O2- in vitro. Due to the basic effect of dissolved lysine, which separates easily in solution from NAL, the acidic function of the remaining NAC molecule is almost completely neutralized [at concentration 2 x 10(-4) M: pH 3.6 (NAC), pH 6.4 (NAL)]. Due to their function as H2O2 scavengers, and due to their ability to enhance cellular glutathione levels, NAL and NAC both have potent antioxidant capabilities in vitro. The advantage of NAL over NAC is two-fold; it enhances intracellular GSH levels twice as effectively, and it forms neutral pH solutions whereas NAC is acidic. Concluding from these in vitro results, NAL could be an interesting alternative to enhance the antioxidant capacity at the epithelial surface of the lung by aerosol administration.

Acetylcysteine↗
PubMed1997

Beta-2-agonists have antioxidant function in vitro. 1. Inhibition of superoxide anion, hydrogen peroxide, hypochlorous acid and hydroxyl radical.

beta(2)-Agonists are known to have anti-inflammatory efficacy. In this context, beta(2)-agonists are also capable of inhibiting oxidant production of cultured inflammatory cells. As the mechanisms of this function still remain speculative, the purpose of this study was to quantify the efficacy of beta(2)-agonists in vitro to inhibit superoxide anion (O2-), hydrogen peroxide (H2O2), hydroxyl radical (OH.) and hypochlorous acid (HOCl). We tested the following antiasthma drugs: ipratropium bromide, salbutamol (salbutamol base), fenoterol (fenoterol hydrobromide), terbutaline (terbutaline sulfate), isoproterenol, prednisolone (prednisolone hydrogensuccinate), beclomethasone (beclomethasone dipropionate) and theophylline (theophylline sulfate). Antioxidant function was quantified by using the following assay systems: O2- (ferricytochrome c + xanthine/xanthine oxidase), H2O2 (phenol red + 5.10(-6) M H2O2), OH. (deoxyribose assay) and HOCI (HOCl/OCl- in luminol-dependent chemiluminescence). At 10(-4) M, the anti-H2O2 and anti-O2- capacity was as follows: salbutamol/terbutaline < fenoterol < isoproterenol. All beta(2)-agonists (10(-4) M) tested reduced HOCl activity by > 50% (p < 0.01). In contrast, moderate OH. reduction (10-30%) by the beta(2)-agonists is regarded as an nonspecific effect, due to the high concentrations needed (10(-3) M). Corticosteroids and theophylline had no antioxidant effect. These results demonstrate the different redox potentials of different phenol types within the molecular structure of the beta(2)-agonists. The good antioxidative function of isoproterenol is related to ortho formation of the phenol ring, whereas fenoterol has tow phenol rings which can be oxidized. A direct oxidant scavenger function may explain the ability of beta(2)-agonists to reduce the oxidant production of inflammatory cells in vitro.

Adrenergic beta-Agonists↗
PubMed1997

Beta-2-agonists have antioxidant function in vitro. 2. The effect of beta-2-agonists on oxidant-mediated cytotoxicity and on superoxide anion generated by human polymorphonuclear leukocytes.

Therapeutic agents which may be able to enhance the antioxidant screen of the epithelial surface of the lung have the potential to influence the progression of lung inflammation. This study evaluates the efficacy of a variety of antiasthma drugs to reduce oxidant-mediated cytotoxicity and to inhibit superoxide anion generated by human polymorphonuclear leukocytes. We quantified in vitro the prevention of H2O2-mediated cytotoxicity (lactate dehydrogenase release assay) using the antiasthma drugs as follows: ipratropium bromide, salbutamol (salbutamol base), fenoterol (fenoterol hydrobromide), terbutaline terbutaline sulfate), isoproterenol, prednisolone (prednisolone hydrogensuccinate), beclomethasone (17,21-beclomethasone dipropionate) and reduced glutathione. Furthermore, fenoterol and isoproterenol were evaluated ex vivo to reduce superoxide anion (O2-) generated by freshly isolated polymorphonuclear cells (PMN) from smokers with chronic obstructive lung disease (n = 10). Using a concentration of 10(-4) M, reduction of cytotoxicity was quite different among beta(2)-agonists: fenoterol (97.8%) > isoproterenol (67.6% > salbutamol (41.8%) > terbutaline (30.5%) > ipratropium bromide (18.1%). Corticosteroids and theophylline had no antioxidant effect. The cellular O2- production of freshly isolated PMN was significantly (p < 0.05, comparisons 0 vs. > or = 10(-7) M) reduced with fenoterol and isoproterenol at concentrations > or = 10(-7) M. Propranolol had no inhibitory effect on antioxidant properties of beta(2)-agonists. We hypothesize that the antioxidant function of beta(2)-agonists is related to the number and formation of hydroxyl groups of the phenol rings within their molecular structure. These results demonstrate that beta(2)-agonists have in part a good intrinsic scavenger function on reactive oxygen species when used in micromolar concentrations. However, to achieve this effect supratherapeutic concentrations were necessary. Thus, the conceivable benefit of beta(2)-agonists in the treatment of high oxidant burden in vivo seems doubtful.

Adrenergic beta-Agonists↗
PubMed1996

[Chronic bronchitis and its sequelae. Therapy--prognosis--insurance medicine aspects].

Chronic bronchitis is of enormous epidemiological, socio-medical and economical importance. The main cause of chronic bronchitis is active but also passive cigarette smoking. Other etiologic factors are: viral or bacterial infections, chronic dust exposure in occupational settings and air pollution. Cease of cigarette smoking is considered the most valuable action in the treatment of the chronic bronchitis. In addition to drug therapy, physical therapy and other measures of rehabilitation may be a supportive benefit. ABout 10-20% of all patients with chronic bronchitis develop airway obstruction and/or lung emphysema. Obstructive bronchitis with or without lung emphysema should be treated with corticosteroids, beta 2-agonists and/or theophylline. Evidence for the socio-economical burden of chronic bronchitis and its complications are the enormous costs for the social economy (direct costs: in- and outpatient treatment; indirect costs: premature pensions, sick leave).

Bronchitis↗
PubMed1996

Activated neutrophils secrete stored alpha 1-antitrypsin.

Neutrophil elastase (NE), a potent serine protease, is stored in primary granules of neutrophils and released following neutrophil activation. Alpha-1-antitrypsin (alpha 1-AT), the major inhibitor of NE, is synthesized by mature neutrophils. In the context of the maintenance of tissue homeostasis, we hypothesized that neutrophils may be able to store alpha 1-AT, thus having it available for release concordantly with NE. Immunofluorescence and quantitative flow-cytometric studies of neutrophils and monocytes labeled with fluorescein-conjugated alpha 1-AT-antibody demonstrated larger amounts of cytoplasmic alpha 1-AT in neutrophils than in monocytes. [35S]methionine-labeling and anti-alpha 1-AT immunoprecipitation analysis showed that although both neutrophils and monocytes synthesize alpha 1-AT, the proportion of newly synthesized intracellular alpha 1-AT was much higher in neutrophils than in monocytes. Flow-cytometric analysis showed that in the presence of surface stimulation with cytochalasin B followed by formyl-methionyleucylphenylalanine (fMLP), mean intracellular alpha 1-AT was decreased in stimulated neutrophils compared with that in resting cells, suggesting that the stored alpha 1-AT was rapidly released following surface triggering. Evaluation of surface-stimulated neutrophils by [35S]methionine labeling and anti-alpha 1-AT immunoprecipitation demonstrated increased secretion of alpha 1-AT compared with that of resting neutrophils, with some of the secreted alpha 1-AT capable of forming complexes with NE. Thus, neutrophils respond to surface stimulation not only by secreting NE but also by secreting its inhibitor, alpha 1-AT, suggesting that these cells have an inherent mechanism for damping the local effects of NE, their most powerful proteolytic enzyme.

Cytochalasin B↗
PubMed1996

Use of secretory leukoprotease inhibitor to augment lung antineutrophil elastase activity.

Physiologically, secretory leukoprotease inhibitor (SLPI) is the major antiprotease of the epithelium of the upper respiratory tract providing protection against neutrophil elastase (NE). The recombinant form of SLPI (rSLPI) has several advantages compared with alpha 1-antitrypsin that make it interesting as potential therapy. In vitro, rSLPI proves to be an excellent inhibitor of NE. When administered as an aerosol in vitro and in vivo, the structure and function of rSLPI remain intact. Using the aerosol route, the half-life of rSLPI in respiratory epithelial lining fluid is 12 h; thus, giving it twice daily should guarantee satisfactory levels in the lung. Following inhalation, rSLPI moves from the epithelium in an intact form into the interstitium of the lung. Following on from these in vitro and in vivo experiments, a short-term study in patients with cystic fibrosis was performed with aerosolized rSLPI. Promising results relative to NE level reduction and the consequences for the inflammatory process in the bronchi were achieved. rSLPI not only induced an increase of the anti-NE protective screen, but also improved the antioxidant protection by raising glutathione levels in the lung in sheep. rSLPI may therefore provide a unique opportunity for protecting the lung from the damage caused by inflammatory processes by giving a single drug.

Animals↗
PubMed1995

[N-acetylcysteine: a functional oxygen radical scavenger in vitro and ex vivo in monocytes and neutrophilic granulocytes of patients with COPD].

In order to develop an efficient antioxidant therapeutic regime for inflammatory disease in the lung N-acetylcysteine (NAC) and reduced glutathione (GSH) were tested to inhibit O2 and H2O2 in vitro and ex vivo. NAC and GSH inhibited both at > or equal to 10(-4)M significantly H2O2 (5 x 10(-8)) mol/ml; p < 0.05). In contrast, in an assay consisting of xanthine/xanthine oxidase/ferricytochrome c Cu++/Zn++ superoxide dismutase (SOD), but not NAC and GSH had an anti-O2 effect (SOD: at > or equal to 10(-5)M, p < 0.01 when compared with 0). In accordance with these results, NAC and GSH had good anti-H2O2 efficacy in freshly isolated and ex vivo cultured mononuclear (MN) and polymorphonuclear cells (PMN) derived from patients with COPD (smoker, n = 30). Both drugs reduced H2O2 significantly when used in concentrations already at > or equal to 10(-9)M (p < 0.05). However, neither GSH nor NAC influenced O2 produced by these inflammatory cells effectively. Antioxidative properties of NAC are well explained by the SH-group within the molecular structure which can be oxidized by certain oxygen radicals. Good H2O2 scavenger function ex vivo, which seems to contradict the results obtained in vitro, illustrates additional cellular GSH-precursor efficacy of both substances in cell dependent assay systems. Thus, to achieve direct anti-H2O2 efficacy in vivo high local NAC concentrations (10(-4)M)) are necessary.

Acetylcysteine↗
PubMed1994

Neurotoxicity, haemostatic disturbances and haemolytic anaemia after a bite by a Tunisian saw-scaled or carpet viper (Echis 'pyramidum'-complex): failure of antivenom treatment.

A young man in Germany was bitten by a large captive saw-scaled viper (Echis 'pyramidum'-complex) of Tunisian origin. During the first few hours after the bite he developed evidence of disseminated intravascular coagulation and fibrinolysis, and bled spontaneously. Despite being given a total of 310 ml of three different Echis-specific antivenoms (together with large amounts of fresh frozen plasma and concentrated clotting factors), venom antigenaemia (measured by enzyme immunoassay) and coagulopathy persisted for more than 10 days, and he developed a haemolytic anaemia and mild renal dysfunction. Transient bilateral ptosis was attributed to envenoming. The venom of the snake responsible for the bite was immunologically distinct from that of Nigerian E. ocellatus and was clearly not neutralised by the three monospecific antivenoms which had been administered. This case is another illustration of the geographical variation in snake venoms and the need for pooling venoms from snakes from different parts of the geographical range in the preparation of antivenoms. Envenoming by North African Echis species may not be reversible by available antivenoms.

Adult↗
PubMed1994

A rare manifestation of von Recklinghausen neurofibromatosis: advanced neurofibromatous infiltration in lung of a HIV-positive patient.

This is a report of a 28-year-old HIV+ man with extensive involvement of lungs, spinal roots and peripheral nerves by neurofibromatosis von Recklinghausen. Huge masses (neurofibromas) ventral of the spine, which already infiltrated into the foramina intervertebralia, could be located by magnetic resonance imaging and high resolution computer tomography. Strikingly, most biopsies taken by bronchoscopy of the bronchial wall from various parts of the airways revealed extended infiltration by neurofibromas in submucosal areas, but no malignant tissue components. In addition, HIV infection with low CD4/CD8 ratio (0.1) and low CD4+ cells (160/microliters) was found.

Adult↗
PubMed1993

Recombinant secretory leukoprotease inhibitor augments glutathione levels in lung epithelial lining fluid.

Secretory leukoprotease inhibitor (SLPI), a 12-kDa serine antiprotease, serves as the major inhibitor of neutrophil elastase (NE) on the epithelial surface of the upper airways. As a control for studies to evaluate the aerosol administration of recombinant SLPI (rSLPI) to augment the anti-NE defenses of the lung, the status of antioxidants in respiratory epithelial lining fluid (ELF) was evaluated. Unexpectedly, aerosol administration of rSLPI caused an elevation in ELF glutathione, a major component of the epithelial antioxidant screen; i.e., rSLPI may provide not only augmentation of anti-NE defenses but also antioxidant defenses. To evaluate this concept, rSLPI (100 mg) was aerosolized to sheep, and SLPI, glutathione, anti-NE capacity, and anti-H2O2 capacity were evaluated in respiratory ELF over a 30-h period. As expected, aerosolization of rSLPI increased ELF SLPI levels and anti-NE capacity. Strikingly, postaerosol levels of glutathione in ELF were also increased (5-fold 24 h after aerosol), with a concomitant increase in ELF anti-H2O2 capacity; i.e., the rSLPI augmented the antioxidant screen of ELF. This suggests that rSLPI may be particularly well suited for therapy in lung diseases characterized by excess of both serine proteases and oxidants on the respiratory epithelial surface.

Aerosols↗
PubMed1993

In vivo antioxidant gene expression in human airway epithelium of normal individuals exposed to 100% O2.

Human bronchial epithelium is exquisitely sensitive to high O2 levels, with tracheobronchitis usually developing after 12 h of exposure to 100% O2. To evaluate whether this vulnerability results from inability of the bronchial epithelium to provide adequate antioxidant protection, we quantified antioxidant gene expression in bronchial epithelium of normal volunteers at baseline and after exposure to 100% O2 in vivo. After 14.8 +/- 0.2 h of 100% O2, 24 of 33 individuals had evidence of tracheobronchitis. Baseline gene expression of CuZn superoxide dismutase (SOD), MnSOD, and catalase in bronchial epithelium was very low (CuZnSOD 4.1 +/- 0.8 transcripts/cell, MnSOD 5.1 +/- 0.9, catalase 1.3 +/- 0.2), with control gamma-actin expression relatively abundant (50 +/- 6 transcripts/cell). Importantly, despite 100% O2 exposure sufficient to cause tracheobronchitis in most individuals, antioxidant mRNA transcripts/cell in bronchial epithelium did not increase (P > 0.5). Catalase activity in bronchial epithelium did not change after exposure to hyperoxia (P > 0.05). Total SOD activity increased mildly (P < 0.01) but not sufficiently to protect the epithelium. Together, the very low levels of expression of intracellular antioxidant enzymes and the inability to upregulate expression at the mRNA level with oxidant stress likely have a role in human airway epithelium susceptibility to hyperoxia.

Actins↗
PubMed1993

Aerosolization of superoxide dismutase. Augmentation of respiratory epithelial lining fluid antioxidant screen by aerosolization of recombinant human Cu++/Zn++ superoxide dismutase.

Various human pulmonary diseases are characterized by an increased oxidant burden on the respiratory epithelial surface. As a step toward developing a therapy to augment the antioxidant defenses of respiratory epithelial lining fluid (ELF) of the human lung, we have evaluated the feasibility of aerosolizing a human protein antioxidant to the respiratory epithelial surface of an experimental animal sufficiently large to permit repetitive sampling of ELF. To accomplish this, recombinant human Cu++/Zn++ superoxide dismutase (rSOD) was aerosolized to sheep, and the levels of human superoxide dismutase (SOD) and antisuperoxide anion (O2.-) capacity were quantified in ELF over time. In vitro aerosolization did not alter the specific activity of rSOD (p > 0.5). In vivo aerosolization of rSOD (100 mg) to sheep (n = 7) resulted in peak amounts of human Cu++/Zn++ SOD in ELF of 3.1 +/- 0.6 mumol/L, with a parallel increase in the anti-O2.- capacity of ELF. For the duration of the study (5 h), levels of SOD and anti-O2.- in ELF remained elevated, with a value 50 percent of the peak at 5 h. Aerosolization of phosphate-buffered saline (n = 5) had no effect on SOD or anti-O2.- levels in ELF. In animals receiving rSOD, there was no change in the specific activity of SOD recovered in ELF compared to the starting material (p > 0.4). We conclude that rSOD can be delivered by aerosol to the ELF of a large animal with preservation of specific activity and that a substantial increase in both the amount of SOD and the anti-O2.- capacity can be achieved for a period of time applicable to human therapy, supporting the rationale for evaluation of rSOD aerosol as an antioxidant in human pulmonary disease.

Aerosols↗
PubMed1993

[Lung function and normal values].

Interindividual derived predicted values of lung function are not suitable for detection of early changes of lung function. Intraindividual values show variability, which should be considered. Many of the very common obstructive lung diseases start with small variations of the individual values of lung function, long time before clinical manifestation takes place. Followup of the most useful measurements (FEV1, MEF 50%, Rt und IGV%) show reliable early changes, important for preventive therapeutic intervention. Strong variability of the individual values argue for hyperreagibility of the airways, even as a risk factor for manifestation of obstructive airway diseases.

Adult↗