References of "Lekeux, Pierre"
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See detailCaractériser un profil inflammatoire grâce à l'utilisation du microdamier
Ramery, Eve ULg; Closset, Rodrigue; Bureau, Fabrice ULg et al

Poster (2007)

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See detailHelenalin reduces Staphylococcus aureus infection in vitro and in vivo
Boulanger, D.; Brouillette, E.; Jaspar, F. et al

in Veterinary Microbiology (2007), 119(2-4), 330-338

Staphylococcus (S.) aureus is a major udder pathogen causing bovine mastitis. Some pro-inflammatory cytokines, including tumor necrosis factor-alpha (TNF-alpha), enhance extracellular and intracellular ... [more ▼]

Staphylococcus (S.) aureus is a major udder pathogen causing bovine mastitis. Some pro-inflammatory cytokines, including tumor necrosis factor-alpha (TNF-alpha), enhance extracellular and intracellular growth of S. aureus, indicating that the inflammatory process favors S. aureus infection. Helenalin is a sesquiterpene lactone with potent anti-inflammatory properties. This study was designed to evaluate the effects of helenalin on S. aureus infection. First, in vitro experiments were conducted. These studies revealed that proliferation of S. aureus in bovine mammary epithelial MAC-T cells treated in the presence or absence of TNF-alpha was markedly reduced in the presence of helenalin. Secondly, in vivo effects of helenalin were investigated. Lactating mice treated in the presence or absence of helenalin were challenged by the intramammary route with S. aureus and the bacteria in the mammary glands were counted 12 h after infection. Significantly less numbers of bacteria were recovered from the infected glands of helenalin-treated mice compared with untreated mice. Moreover, histological examination of mammary tissue from helenalin-treated mice that were challenged with S. aureus indicated that helenalin is able to significantly reduce leukocyte infiltration in the mammary gland following S. aureus inoculation. Our results show that helenalin reduces S. aureus intracellular growth and experimental S. aureus infection. We conclude that helenalin may be of potential interest in the treatment of S. aureus-induced mastitis in the bovine species. [less ▲]

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See detailQualitative and quantitative evaluation of equine respiratory mechanics by impulse oscillometry
Van Erck, Emmanuelle; Votion, Dominique ULg; Art, Tatiana ULg et al

in Equine Veterinary Journal (2006), 38(1), 52-58

Reasons for performing study: The long- established conventional reference technique (CRT) for measuring respiratory mechanics in horses lacks sensitivity and there is a need for further refinement in new ... [more ▼]

Reasons for performing study: The long- established conventional reference technique (CRT) for measuring respiratory mechanics in horses lacks sensitivity and there is a need for further refinement in new technology, such as the impulse oscillometry system (IOS). Objectives: To evaluate the potential use of the IOS as a clinical respiratory function test and compare it to the current CRT in horses suffering from common upper and lower airway dysfunctions. Methods: Six healthy horses were tested before and after induction of a unilateral nasal obstruction (UNO) or transient left laryngeal hemiplegia. (LLH). Six heaves-affected horses were tested in clinical remission and during a heaves crisis, before and after nebulisation of cumulative doses of a bronchodilator therapy (ipratropium bromide; IPB). Results: As opposed to the CRT, the IOS was able to detect partial upper airway obstruction (UAO) caused by UNO or LLH in resting horses, without differentiating both conditions. Upper airway obstruction caused an upward shift of resistance (R-rs) from 5 to 35 Hz without altering reactance (X-rs). As for the CRT, IOS respiratory parameters measured in heaves-affected horses in crisis differed significantly from values measured during remission. The difference in frequency-dependent behaviour of R-rs and X-rs allowed discrimination between upper and lower airway obstructions. Bronchodilator treatment induced significant dose-dependent changes in X-rs at 5 and 10 Hz, from the first dose. Total pulmonary resistance (R-L) and R-rs at 5 Hz were affected from the second dose and displayed similar sensitivity. Although post treatment R-L values were comparable to remission, R-rs and X-rs remained significantly different, characterising persistent peripheral obstruction. Conclusions: The IOS was more sensitive than the CRT in detecting partial UAO in resting horses and persistent post treatment peripheral dysfunction in heaves-affected horses. The IOS is a sensitive test that provides graded quantitative and qualitative information on disease-induced respiratory dysfunctions as well as on treatment efficiency in horses. Potential relevance: The IOS could represent a practical and sensitive alternative respiratory function test for routine clinical investigations of common airway obstructive diseases and therapy in horses. [less ▲]

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See detailTableau clinique et mécanismes physiopathologiques des principales maladies inflammatoires chroniques des voies respiratoires du cheval
Mesnil, Claire ULg; Bureau, Fabrice ULg; Lekeux, Pierre ULg

in Annales de Médecine Vétérinaire (2006), 150(4), 227-240

The respiratory tract of the horse can be the seat of several chronic inflammatory diseases whose principal ones are the recurrent airway obstruction, the inflammatory airway disease, the summer pasture ... [more ▼]

The respiratory tract of the horse can be the seat of several chronic inflammatory diseases whose principal ones are the recurrent airway obstruction, the inflammatory airway disease, the summer pasture-associated obstructive pulmonary disease and the follicular pharyngitis. These diseases can have an important impact on horses’ health and on their sports performances. A good knowledge of their aetiologies and their physiopathological mechanisms would allow a better control of these affections. However, even if many studies were made on this subject, there are currently very few certainties as for the inflammatory mechanisms governing these diseases. This article aims to make an inventory of knowledge and deficiencies concerning these four chronic inflammatory diseases [less ▲]

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See detailInvasion intracellulaire des cellules non-phagocytaires par Staphylococcus aureus
Boulanger, Delphine; Bureau, Fabrice ULg; Lekeux, Pierre ULg

in Annales de Médecine Vétérinaire (2006), 150(1), 27-42

Intracellular invasion of Staphyloccocus aureus in nonphagocytic cells Staphylococcus aureus often causes chronic diseases. It is now believed that recurrence of these infections could be related to the ... [more ▼]

Intracellular invasion of Staphyloccocus aureus in nonphagocytic cells Staphylococcus aureus often causes chronic diseases. It is now believed that recurrence of these infections could be related to the ability of S. aureus to invade and persist within nonphagocytic cells. Adherence to eucaryotic cells is crucial for S. aureus to invade and persist within invasion and depends on interactions between bacterial fibronectin-binding proteins, fibronectin and the host cell fibronectin receptor, integrin alpha(5)beta(1). It is currently established that fibronectin acts as a bridging molecule. Penetration of S. aureus in host cells requires also activation of protein tyrosine kinases that mediate signal transduction and actin polymerization leading to cytoskeletal rearrangements. After internalization, S. aureus either remains in membrane-bound vacuoles or appears free in the cytoplasm. After bacterial proliferation, S. aureus induces host cell apoptosis or persist inside cells as small colony variants, which represent a less virulent subpopulation of S. aureus that grows slower. Although numerous in vitro and in vivo studies have demonstrated the ability of S. aureus to invade nonphagocytic cells, additional experiments have to be realized to understand the relevance of intracellular localization in vivo. [less ▲]

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See detailLa mammite bovine : de l’initiation à la résolution
Boutet, Philippe ULg; Bureau, Fabrice ULg; Lekeux, Pierre ULg

in Annales de Médecine Vétérinaire (2006), 150(1), 1-26

The bovine mastitis : from initiation to resolution The cure of a cow suffering from a bacterial mastitis relies on the balance between the eradication of the pathogen and the resolution of the ... [more ▼]

The bovine mastitis : from initiation to resolution The cure of a cow suffering from a bacterial mastitis relies on the balance between the eradication of the pathogen and the resolution of the inflammatory response, two processes that are essential to come back to a normal milk composition with low somatic cell count. The persistence of the inflammatory response, which main consequence is a reduction in milk yield, is a feature of chronic mastitis. This frequent disease depends on inappropriate host-pathogen interactions and is not yet well understood. This review resumes the main defence mechanisms of the bovine mammary gland, emphasizing the predominant roles played by the neutrophil, and brings some precisions on lipoxin implications in the resolution of inflammation. Reasons that may explain the persistence of the inflammatory reaction, a phenomenon found in the Staphylococcus aureus chronic mastitis, are also discussed. [less ▲]

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See detailUtilisation d'un concentré riche en fibres pour la prévention des crises chez le cheval poussif
Bedoret, Denis; de Moffarts, Brieuc; Van Erck, Emmanuelle et al

in Pratique Vétérinaire Equine (2006), 38(149), 57-64

"Heaves" is a recurrent allergic inflammatory disease initiated by inhalation of organic dust from hay and litter. Reduction in exposure to dust is the basis of prevention and treatment of attacks in ... [more ▼]

"Heaves" is a recurrent allergic inflammatory disease initiated by inhalation of organic dust from hay and litter. Reduction in exposure to dust is the basis of prevention and treatment of attacks in horses. Substitution of hay by wilted grass silage is recommended but is often not given because of the required high work load and possible risk of botulism. An alternative is the use of fibrous food without forage. Nine "heave" horses were placed in two groups at random. One group received concentrate enriched with short-strand lucerne for six weeks and the other group the reference feed consisting of silage based concentrate. After a period of recovery, the protocol was repeated and the groups reversed. Respiratory and circulatory functions, degree of fatness, feeding time and consumption of water were evaluated. No significant difference in respiratory and circulatory parameters was observed. The feeding time was significantly higher for concentrate enriched with lucerne fibers. A concentrate rich in fibers may limit attacks as does silage, which has risks associated with consumption [less ▲]

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See detailEvaluation des troubles fonctionnels du système respiratoire du cheval
Salinas, E.; Van Erck, Emmanuelle ULg; Lekeux, Pierre ULg et al

in Pratique Vétérinaire Equine (2006), 38(150), 29-39

Les troubles respiratoires sont fréquents chez le cheval. Il existe des tests fonctionnels complémentaires, réalisables soit sur le terrain soit en centres spécialisés.

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See detailInvestigation of blood oxidant/antioxidant markers in healthy competition horses of different breeds
Kirschvink, Nathalie; de Moffarts, Brieuc; Farnir, Frédéric ULg et al

in Equine Veterinary Journal. Supplement (2006), 36

REASONS FOR PERFORMING STUDY: There is increasing evidence that the equine athlete is exposed to exercise-induced changes of its oxidant/antioxidant balance and antioxidant supplementation is frequently ... [more ▼]

REASONS FOR PERFORMING STUDY: There is increasing evidence that the equine athlete is exposed to exercise-induced changes of its oxidant/antioxidant balance and antioxidant supplementation is frequently recommended. However, it is unknown whether there is a specific need for antioxidants according to performance, breed, gender or age. OBJECTIVES: To assess whether breed-, gender- and age-related differences of blood oxidant/antioxidant markers occur in competition horses. METHODS: Healthy horses (n = 493) underwent oxidant/ antioxidant blood marker determination. Vitamin E, lipophilic antioxidant capacity (ACL), ascorbic acid (AA), glutathione (GSH, GSSG), gluthione peroxidase (GPx), superoxide dismutase (SOD), selenium (Se), copper (Cu), zinc (Zn), lipid peroxides (Pool), oxidised proteins (Protox) were determined, as well as magnesium (Mg), creatine phosphokinase (CPK), lactate dehydrogenase (LDH), packed cell volume (PCV) and haemoglobin (Hb). A mixed linear model assessed the effect of breed, gender and age category. P<0.05 was considered significant. RESULTS: Thoroughbreds showed the highest values of vitamin E, ACL, GPx, PCV and Hb, whilst standardbreds had the highest values of AA and LDH. Jumping horses had the highest Protox values. Females had significantly higher SOD values, whereas most of the other markers were higher in stallions and geldings. Horses age 2-6 years had higher AA, SOD and LDH values than horses age >6 years. Correlation analyses were positive and significant between vitamin E and GPx, VitE and ACL, Se and GPx, Cu and Pool and negative between Pool and vitamin E, Pool and ACL, Protox and GPx, Protox and vitamin E. CONCLUSIONS: Blood oxidant/ antioxidant status of horses is influenced by breed, gender and age. The correlation analyses suggest synergistic relations between GPx, vitamin E and Se and an antagonistic relation between Protox-GPx, Protox-vitamin E, and Pool-vitamin E. POTENTIAL RELEVANCE: The results of this investigation provide definition of the specific need for antioxidants and vitamins in competition horses. [less ▲]

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See detailProlactine triggers a pro-inflamatory response in bovine mammary epithelial cells
Boutet, Philippe ULg; Sulon, Joseph; Detilleux, Johann ULg et al

in Proceedings: 24th World Buiatrics Congress (2006)

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See detailBRDC and the modulation of lung inflammation.
Lekeux, Pierre ULg

in Veterinary Journal (2006), 171(1), 14-5

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See detailEffect of exercise on blood oxidant/antioxidant markers in standardbred horses: comparison between treadmill and race track tests.
de Moffarts, Brieuc; Kirschvink, Nathalie; Art, Tatiana ULg et al

in Equine Veterinary Journal. Supplement (2006), (36), 254-257

REASONS FOR PERFORMING STUDY: Interest in establishing oxidant/ antioxidant profiles in competition horses is increasing. Earlier studies performed in horses have mainly been performed under laboratory ... [more ▼]

REASONS FOR PERFORMING STUDY: Interest in establishing oxidant/ antioxidant profiles in competition horses is increasing. Earlier studies performed in horses have mainly been performed under laboratory conditions using a treadmill and it is not known to what extent laboratory results of oxidant/antioxidant studies might be transposed to field conditions. OBJECTIVE: To compare the impact on the blood oxidant/ antioxidant status of a standardised exercise test including a run up to fatigue performed on a treadmill (TM) and on a racetrack (RT) in healthy and trained Standardbred horses. MATERIAL AND METHODS: During TM and RT tests the following blood antioxidant markers were analysed in jugular venous blood at rest and 15 mins (E15) after an intense bout of exercise: uric acid (UA), ascorbic acid (AA), superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione (reduced: GSH and oxidised: GSSG), glutathione redox ratio (GRR) and protein thiol (PSH). Running time to fatigue (RTF), velocity during the last exercise stage (Vmax), final heart rate (HRfinal) and venous lactic acid (LA) were also recorded. RESULTS: Vmax was significantly (P<0.05) higher during the RT, whereas LA was significantly lower. HRfinal and RTF did not differ significantly between TM and RT. Exercise induced a significant increase (R vs. E15) of UA and AA in both tests, whereas GSH and PSH decreased significantly. GPx, SOD, GSSG and GRR remained unchanged. Differences between TM and RT were significant at E15 for UA, AA and PSH. CONCLUSIONS: Comparison of oxidant/antioxidant profiles from laboratory and field studies are difficult to standardise and should be interpreted with caution. POTENTIAL RELEVANCE: For the same RTF and final HR, the TM induced stronger changes in blood lactate and in blood oxidant/antioxidant balance than did RT. [less ▲]

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See detailNew trends in the diagnosis and treatment of recurrent inflammation in competition horses
Lekeux, Pierre ULg; Thomas, A.; Art, Tatiana ULg et al

in Pferdeheilkunde (2006)

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See detailEvaluation of a portable equine metabolic measurement system
Duvivier, V. H.; Van Erck, Emmanuelle; De Moffarts, Brieuc et al

in 7th International Conference on Equine Exercise Physiology (2006)

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See detailField evaluation of poor performance in Standardbred trotters
Van Erck, Emmanuelle; Jakesova, V.; Lekeux, Pierre ULg et al

in Pferdeheilkunde (2006), 22

Exercise tests allow evaluating athletic capacity and fitness, following training-induced adaptations and determining causes of poor performance. A retrospective study was conducted over the cases of 40 ... [more ▼]

Exercise tests allow evaluating athletic capacity and fitness, following training-induced adaptations and determining causes of poor performance. A retrospective study was conducted over the cases of 40 poor performing Standardbreds referred to an Equine Sports Medicine consultation at a Belgian racetrack. The study aimed at determining if the implementation of a standardised exercise test and determination of specific athletic parameters could discriminate between the poor performers and a group of eight healthy racehorses and help in establishing a diagnosis. After a through clinical examination, the horses were submitted to an exercise test that consisted of 3 bouts of 1500m at increasing speeds with a recovery phase of 500 m in between. Speed and heart rate were continuously monitored and blood lactate concentrations were evaluated after each step. Pre and post-effort blood work and respiratory endoscopy with sampling were done in each horse. Five main causes of poor performance were identified: locomotor, respiratory, cardiac, muscular problems and inadequate training. In the poor performers group, 24 horses suffered from upper and/or lower respiratory disease, 20 from lameness, 4 from cardiac disease, 4 from exercise-induced myopathy and 5 from maladjusted training. More than half of the horses had multiple problems (23 horses). The fitness parameters (V-LA4, V-200) obtained were useful for inter-individual comparisons and discriminated poor performers from healthy controls, whatever the cause of the intolerance. This study confirms the high prevalence of lameness and respiratory diseases as causes of poor performance in racehorses. The field exercise tests were readily performed with minimal equipment and enabled to identify conditions which were not clearly apparent as during the clinical examination at rest. The recovery of maximum information by a thorough questioning of the trainer and selected ancillary examinations was critical to reach a diagnosis. [less ▲]

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See detailValidation of a portable equine metabolic measurement system
Art, Tatiana ULg; Duvivier, D. H.; van Erck, Emmanuelle et al

in Equine Veterinary Journal. Supplement (2006), 36

REASONS FOR PERFORMING STUDY: In equine sports medicine, VO2 has been measured exclusively with stationary systems, in laboratories equipped with a treadmill. Measurement during exercise in field ... [more ▼]

REASONS FOR PERFORMING STUDY: In equine sports medicine, VO2 has been measured exclusively with stationary systems, in laboratories equipped with a treadmill. Measurement during exercise in field conditions has not previously been reported because of the lack of portable equipment designed for horses. OBJECTIVES: A commercially available portable metabolic measurement system, based on breath-to-breath gas analysis and flow spirometry, was adapted to the horse's physiology and morphology (Cosmed K4b2 and Equimask) and its validity tested by (1) repeatability of the measures and (2) comparing metabolic data to those obtained by a reference method (RM). METHODS: To test the reproducibility of the measurements, 5 healthy saddle horses were subjected twice at 2 day intervals to a similar submaximal standardised incremental exercise test on a treadmill. The same horses performed twice at one week interval an incremental treadmill test to fatigue: the oxygen consumption and ventilation were measured once with the K4b2 system and once with the RM. The metabolic and ventilatory data obtained with both systems were compared. RESULTS: There was a good reproducibility of the metabolic measurements obtained by the K4b2 system at any workload. The VO2 obtained by both systems at any workload was not significantly different. However, the K4b2 expired fraction in CO2 (FETCO2) and carbon dioxide production (VCO2) were significantly lower at high and at maximal workloads. As a consequence, the values of the respiratory exchange ratio were too low and incompatible with normal physiological values. CONCLUSIONS: The good reproducibility of the metabolic and ventilatory measurements and the fact that the VO2 measurements at any workload were similar to the data obtained with the reference method suggested that this system may be used for comparison of repeated VO2 measurements in practical field conditions. POTENTIAL RELEVANCE: The K4b2 system could be used to improve knowledge of the energetic cost in different equine sports disciplines and offer the opportunity to undertake performance tests with genuine track conditions, on ridden or harnessed horses, rather than under laboratory conditions [less ▲]

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See detailMyeloperoxidase concentration in bronchoalveolar lavage fluid from healthy horses and those with recurrent airway obstruction
Art, Tatiana ULg; Franck, Thierry ULg; Lekeux, Pierre ULg et al

in Canadian Journal of Veterinary Research = Revue Canadienne de Recherche Vétérinaire (2006), 70(4), 291-296

The aim of this work was to measure the myeloperoxidase (MPO) concentration in bronchoalveolar lavage (BAL) fluid collected from horses with recurrent airway obstruction (RAO), both in crisis and in ... [more ▼]

The aim of this work was to measure the myeloperoxidase (MPO) concentration in bronchoalveolar lavage (BAL) fluid collected from horses with recurrent airway obstruction (RAO), both in crisis and in remission, as well as from healthy horses. Seven horses with RAO were exposed to moldy hay until the maximum change in pleural pressure was greater than 1.5 kPa. At that point, BAL was performed, and the total cell counts and percentages in the fluid were immediately determined. To measure the MPO concentration in BAL-fluid supernatant, we used a specific enzyme-linked immunosorbent assay with polyclonal antibodies against equine MPO. The tests were repeated on the horses with RAO after they had spent 2 mo on pasture. Six healthy horses serving as controls underwent the same tests. The absolute and relative neutrophil counts and the MPO concentration in the BAL fluid were significantly greater in the horses with an RAO crisis than in the control horses. After 2 mo on pasture, the horses that had been in RAO crisis were clinically normal, and their neutrophil counts and MPO levels in BAL fluid had significantly decreased; during remission their neutrophil counts were not significantly different from those in the healthy horses, but their MPO concentration remained significantly higher. This study showed that determining the MPO concentration in a horse's BAL fluid is technically possible and that during remission from RAO the concentration remains higher than normal. Thus, MPO may be a marker of neutrophil presence and activation in the lower airways. [less ▲]

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See detailEffect of Beclomethasone Dipropionate and Dexamethasone Isonicotinate on Lung Function, Bronchoalveolar Lavage Fluid Cytology, and Transcription Factor Expression in Airways of Horses with Recurrent Airway Obstruction
Couetil, L.; Art, Tatiana ULg; de Moffarts, Brieuc et al

in Journal of Veterinary Internal Medicine (2006), 20

Glucocorticoid (GC) therapy is recognized to be effective for the treatment of recurrent airway obstruction (RAO) in horses. Anti-inflammatory properties of GC are thought to be mediated by suppression of ... [more ▼]

Glucocorticoid (GC) therapy is recognized to be effective for the treatment of recurrent airway obstruction (RAO) in horses. Anti-inflammatory properties of GC are thought to be mediated by suppression of inflammatory gene expression via inhibition of transcription factors such as nuclear factor-kB (NF-kB) and activator protein-1 (AP-1). The purpose of this study was to evaluate the effect of low-dose inhaled beclomethasone dipropionate and injectable dexamethasone 21- isonicotinate on clinical signs, pulmonary function, airway cytology, and activity of NF-kB and AP-1 in bronchial cells of RAO-affected horses. Seven horses with RAO were exposed to moldy hay until they developed airway obstruction on 3 separate occasions. In a crossover design, they were then treated with a placebo (injection on day 1), inhaled beclomethasone (500 mg q12h for 10 days), or dexamethasone (0.06 mg/kg, IM on day 1) and monitored for 10 days. Pulmonary function, bronchoalveolar lavage fluid cytology, and NF-kB and AP-1 activity in bronchial brushing cells were measured before (day 1) and after treatment (day 10). Treatment with beclomethasone resulted in significantly improved pulmonary function of RAOaffected horses compared with placebo and dexamethasone treatments. However, none of the treatments had an effect on bronchoalveolar lavage fluid cytology or NF-kB and AP-1 activity. These findings reveal that, in a model of severe RAO, the benefits of low-dose inhaled beclomethasone on pulmonary function are not accompanied by a decrease in airway inflammatory cells or a suppression of transcription factors NF-kB and AP-1 DNA-binding activity. [less ▲]

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