References of "Lejeune, Jean-Philippe"
     in
Bookmark and Share    
Peer Reviewed
See detailSYNOVIOCYTES, NOT CHONDROCYTES, RELEASE FREE RADICALS AFTER CYCLES OF ANOXIA/RE-OXYGENATION
Schneider, Nicole ULg; Mouithys-Mickalad, Ange ULg; Lejeune, Jean-Philippe ULg et al

Poster (2007)

Introduction : An oxidant activity has been implicated in the onset of equine osteoarthritis. Most of the studies have been done on articular chondrocytes, but little is known about the role of ... [more ▼]

Introduction : An oxidant activity has been implicated in the onset of equine osteoarthritis. Most of the studies have been done on articular chondrocytes, but little is known about the role of synoviocytes. Objective : Our aim was to investigate if equine articular chondrocytes, primary synoviocytes or synoviocytes of a continuous cell line are able to produce free radicals after exposure to anoxia and re-oxygenation. Methods : By oxymetry and electron paramagnetic resonance (EPR), we investigated the effects of repeated anoxia/re-oxygenation (A/R) periods on the respiration and production of free radicals by synoviocytes (rabbit HIG-82 cell line and primary equine synoviocytes) and equine articular chondrocytes. Three periods of 20 min anoxia followed by re-oxygenation were applied to 10exp7 cells; O2 consumption was measured before anoxia and after each re-oxygenation. After the last A/R, cellular free radical formation was investigated by EPR spectroscopy with spin trapping technique (n = 3 for each cell line). Results : Both types of synoviocytes showed a high O2 consumption, which was slower after anoxia. By EPR with the spin trap POBN, we proved a free radical formation. Results were similar for equine and rabbit synoviocytes. For chondrocytes, we observed a low O2 consumption, unchanged by anoxia, and no free radical production. Conclusion : These observations suggest an oxidant activity of synoviocytes, potentially important for the onset of osteoarthritis. [less ▲]

Detailed reference viewed: 46 (0 ULg)
Full Text
Peer Reviewed
See detailRadiographic evolution of the forelimb digit in Ardenner horses from weaning to 28 months of age and its clinical significance
Lejeune, Jean-Philippe ULg; Schneider, Nicole ULg; Caudron, Isabelle et al

in Journal of Veterinary Medicine. A, Physiology, Pathology, Clinical Medicine (2006), 53(7), 364-370

Ossification of collateral cartilages is a common radiographic finding in draught horses and indication of a high frequency of interphalangeal osteo-arthropathy have been found in Ardenner horses. This ... [more ▼]

Ossification of collateral cartilages is a common radiographic finding in draught horses and indication of a high frequency of interphalangeal osteo-arthropathy have been found in Ardenner horses. This study first aimed at following the evolution of the digits of the forelimbs on radiographic images in a group of 32 Ardenner horses from weaning to 852 +/- 19 days and, secondly, at evaluating the clinical significance of the observed radiographic changes. At 250 +/- 21 days, only 23% of the horses presented a small separate ossification centre of collateral cartilages above the level of the distal sesamoid bone or at the level of the proximal half of the middle phalanx. At 852 +/- 19 days, 100% of the horses presented an ossification of collateral cartilages but at different stages and grades. The presence and the extent of the ossification of the lateral cartilages were not significantly associated with lameness. Phalanges changes appeared at the average age of 1 year and they were represented by entheseophytes on the dorsal surface of the middle and distal phalanges. The frequency of affected horses increased with age as well as the size of the entheseophytes. This may reflect mechanical stresses applied to the interphalangeal joints. A significant association with the presence of lameness was pointed out. The presence and the severity of phalanges changes could be of importance, in combination with a clinical examination, in improving the selection of horses able to assume work and/or leisure activities. [less ▲]

Detailed reference viewed: 47 (3 ULg)
Full Text
Peer Reviewed
See detailAnatomic variations and degenerative changes in the collateral cartilages and middle and distal phalanges of the forelimb in Ardenner colts
Lejeune, Jean-Philippe ULg; Audigie, Fabrice; Schneider, Nicole ULg et al

in Journal of Equine Veterinary Science (2006), 26(3), 102-112

The anatomic variations and the degenerative changes in the collateral cartilages and middle and distal phalanges in 6 Ardenner colts were characterized by radiography, scintigraphy, and magnetic ... [more ▼]

The anatomic variations and the degenerative changes in the collateral cartilages and middle and distal phalanges in 6 Ardenner colts were characterized by radiography, scintigraphy, and magnetic resonance imaging (MRI). The radiographic changes were assessed between the ages of 16.5 and 25 months. An anatomic variation of the middle and distal phalanges was demonstrated in some of the colts. MRI examination of the 6 colts revealed an association between the deep digital flexor tendon cross-sectional area and body weight as well as foot circumference. Also, a thin collateral sesamoidean (suspensory navicular) ligament was observed subjectively. The presence of an extensive ossification of the collateral cartilages of the foot was found in these young horses. The ossification was characterized by the existence of 2 separate ossification centers, which had a tendency to unite. The radiographic interphalangeal degenerative lesions seen appear as bone remodeling of the dorsal edges of the middle and distal phalanx, on the insertion sites of collateral ligaments of the distal interphalangeal joint, the digital extensor tendon, and the distal interphalangeal joint capsule. [less ▲]

Detailed reference viewed: 37 (5 ULg)
Full Text
Peer Reviewed
See detailHistology of two rice bodies isolated from the stifle of an adult draught horse stallion.
Schneider, Nicole ULg; Heimann, Marianne; Lejeune, Jean-Philippe ULg et al

in Journal of Veterinary Science (Suwon-si, Korea) (2006), 7(1), 83-5

In the human and equine species, different kinds of free floating intra-articular particles are related to certain disorders. Osteochondral fragments formed during osteochondrosis dissecans are the most ... [more ▼]

In the human and equine species, different kinds of free floating intra-articular particles are related to certain disorders. Osteochondral fragments formed during osteochondrosis dissecans are the most common finding in the equine species, whereas in humans rice bodies due to rheumatoid arthritis are more frequent. Herein we report a third type of floating body inside the stifle of an adult draught horse stallion, in macroscopic appearance similar to articular rice bodies known in humans. As revealed by histologic examination, the two particles consist of polypoid degenerated structures derived from synovial villi. Their formation was probably induced by ischemia. [less ▲]

Detailed reference viewed: 100 (11 ULg)
Full Text
Peer Reviewed
See detailDegenerative osteoarthropathy in horses: pathogeny and diagnostic
Lejeune, Jean-Philippe ULg; Schneider, Nicole ULg; Henrotin, Yves ULg et al

in Annales de Médecine Vétérinaire (2006), 150(3), 173-192

This work presents some important features of the normal articular structures and a definition of the degenerative osteo-arthropathy that points the involvement of all the joint structures. The pathogeny ... [more ▼]

This work presents some important features of the normal articular structures and a definition of the degenerative osteo-arthropathy that points the involvement of all the joint structures. The pathogeny of the pathology is tackled by the potential risk factors and by the cartilage-cartilage, synovium-cartilage and bone-cartilage cycles that lay particular emphasis on the interaction between the different joint structures. The diagnostic tools of the degenerative osteo-arthropathy like the conventional or recent imaging techniques (magnetic resonance imaging, scintigraphy and tomography) and the biomarkers of the cartilage and bone metabolisms are listed. The pathogeny of the degenerative osteo-arthropathy is complex and involves different factors. This disease is characterised by an imbalance between the anabolic and catabolic processes of the cartilage metabolism. Inflammation is also present and lead to the clinical signs. The synovitis, the liberation of degradation mediators, the mechanical stresses and/or the subchondral bone are part of the pathogeny at different degrees. The development of recent imaging techniques and the biomarkers of the cartilage and bone metabolisms allow the precise description of the lesions and give some additional information on the pathogeny of the osteo-arthropathy. These recent techniques raise new questions and allow the in-depth analysis of the study of the osteo-arthropathy. [less ▲]

Detailed reference viewed: 167 (7 ULg)
Full Text
Peer Reviewed
See detailSynoviocytes, not chondrocytes, release free radicals after cycles of anoxia/re-oxygenation
Schneider, Nicole ULg; Mouithys-Mickalad, Ange ULg; Lejeune, Jean-Philippe ULg et al

in Biochemical & Biophysical Research Communications (2005), 334(2), 669-673

By oxymetry and electron paramagnetic resonance (EPR), we investigated the effects of repeated anoxia/re-oxygenation (A/R) periods on the respiration and production of free radicals by synoviocytes ... [more ▼]

By oxymetry and electron paramagnetic resonance (EPR), we investigated the effects of repeated anoxia/re-oxygenation (A/R) periods on the respiration and production of free radicals by synoviocytes (rabbit HIG-82 cell line and primary equine synoviocytes) and equine articular chondrocytes. Three periods of 20 min anoxia followed by re-oxygenation were applied to 10(7)cells; O(2) consumption was measured before anoxia and after each re-oxygenation. After the last A/R, cellular free radical formation was investigated by EPR spectroscopy with spin trapping technique (n=3 for each cell line). Both types of synoviocytes showed a high O(2) consumption, which was slowered after anoxia. By EPR with the spin trap POBN, we proved a free radical formation. Results were similar for equine and rabbit synoviocytes. For chondrocytes, we observed a low O(2) consumption, unchanged by anoxia, and no free radical production. These observations suggest an oxidant activity of synoviocytes, potentially important for the onset of osteoarthritis. [less ▲]

Detailed reference viewed: 22 (6 ULg)
See detailSYNOVIOCYTES BUT NOT ARTICULAR CHONDROCYTES RELEASE FREE RADICALS AFTER REPETITIVE CYCLES OF ANOXIA/REOXYGENATION: AN ELECTRON SPIN RESONANCE STUDY.
Schneider, Nicole ULg; Lejeune, Jean-Philippe ULg; Mouithys-Mickalad, Ange ULg et al

Poster (2005)

Objective : We investigated if short recurrent periods of anoxia/reoxygenation (A/R), mimicking the in vivo conditions of hypoxia, could stimulate the production of free radicals by synoviocytes and ... [more ▼]

Objective : We investigated if short recurrent periods of anoxia/reoxygenation (A/R), mimicking the in vivo conditions of hypoxia, could stimulate the production of free radicals by synoviocytes and chondrocytes. Material and Methods : Synoviocytes (immortalised rabbit line HIG-82 and equine synoviocytes isolated from synovial membranes of the stifle joint) and chondrocytes (isolated from the same equine joint) were cultured for 48 hours. The respiration rate of the cells (107 cells/assay) was studied by oxymetry and the free radical production monitored by electron spin resonance (ESR) in the presence of the spin trap (-[-4-pyridyl 1-oxide]-N-tert butyl nitrone)/ethanol mixture (2%v/v). The A/R consisted of three periods of 20 minutes anoxia, each anoxia period being followed by re-oxygenation. Oxygen consumption by the cells was measured before starting the anoxia/reoxygenation cycles and after each reoxygenation. At the end of the last A/R period, the cells were transferred into the ESR flat cell and in the cavity, and the free radical formation was monitored. Results : The equine chondrocytes showed a low respiration rate, weakly affected by A/R and no production of free radicals (n=3). Synoviocytes showed a higher respiration rate (at least 20 times higher) which was affected by recurrent A/R (decrease of the slope of oxygen consumption), and a free radical production as evidenced by the appearance of the 4-POBN/EtOH adducts (n=6). Conclusions :These observations suggest that synoviocytes, but not chondrocytes, responded to repeated anoxia-reoxygenation conditions by the production of free radicals. Synoviocytes could thus be responsible for the production of free radicals in the joints, what could be an important factor in the onset of osteoarthritis. [less ▲]

Detailed reference viewed: 32 (2 ULg)
Full Text
Peer Reviewed
See detailViability of equine articular chondrocytes in alginate beads exposed to different oxygen tensions.
Schneider, Nicole ULg; Lejeune, Jean-Philippe ULg; Deby, Carol et al

in Veterinary Journal (2004), 168

Ischaemia and reperfusion are suspected to alter chondrocyte metabolism. Here, we studied the effects of three oxygen (O2) tensions on the viability of equine articular chondrocytes isolated from the ... [more ▼]

Ischaemia and reperfusion are suspected to alter chondrocyte metabolism. Here, we studied the effects of three oxygen (O2) tensions on the viability of equine articular chondrocytes isolated from the cartilage of the distal interphalangeal joint of horses. Chondrocytes were cultured in alginate beads under 1%, 5% or 21% gas phase O2 concentration for 14 days, cellular growth kinetics were measured (n=6), and the cells were observed by light microscopy after staining for necrotic and apoptotic cell detection. For information about the metabolic status, the intracellular adenosine triphosphate (ATP) content was measured. The number of chondrocytes remained stable for the first eight days, then decreased especially at 1% and 21% O2. At 21% O2, normal cells decreased and necrotic cells increased at the end of the 14 day-period. No significant variations were found at 5% O2 except for a decrease in necrotic cells at day 14. Most apoptotic cells were found at 1% O2 from days 5 to 11, and normal cells decreased during the same period. But an unexpected increase in normal cells and decrease in apoptotic cells were observed at day 14. The intracellular ATP content remained stable. It was concluded that, in a three-dimensional culture model of equine articular chondrocytes, O2 tension affected the viability of the cells after an 11-day period, with the most important effects observed at 21% and 1% O2 conditions. [less ▲]

Detailed reference viewed: 11 (1 ULg)
See detailEFFECTS OF O2 TENSION AND GLUCOSE CONCENTRATION ON THE CELLULAR RESPIRATION OF EQUINE ARTICULAR CHONDROCYTES IN CULTURE.
Schneider, Nicole ULg; Lejeune, Jean-Philippe ULg; Duyckaerts, Claire ULg et al

Poster (2003)

In vivo, articular chondrocytes are exposed to 5 to 10% O2. Chondrocytes are also suspected to produce reactive oxygen species when submitted to anoxia/re-oxygenation. We were interested to study the ... [more ▼]

In vivo, articular chondrocytes are exposed to 5 to 10% O2. Chondrocytes are also suspected to produce reactive oxygen species when submitted to anoxia/re-oxygenation. We were interested to study the effects of O2 and glucose variations on cellular respiration, glucose consumption and lactate production. Equine articular chondrocytes were cultured in suspension for 2 days under 5 or 21 % O2 in the gaseous phase, and with 0, 1.0 or 4.5 g/L glucose. The viable cells were then counted and the respiration rate (O2 consumption) of 10.106 cells was monitored by oxymetry for 2 hours; after oxymetry, glucose and lactate were measured in the medium (enzymatic assays). After 2 days, the cell viability was the best at 5% O2 and 1g/L glucose; it decreased at 4.5 g/L glucose and was the worst at 0g/L glucose, for the two O2 tensions (n=3). There was no obvious difference of the respiration rate between cells cultured at 5 and 21% O2, but respiration of chondrocytes was surprisingly low. When cells were submitted to 20 min anoxia at 0% O2, the O2 consumption was doubled at re-oxygenation for cells previously cultured at 21% O2. Glucose and lactate values found in the medium after oxymetry: lactate release in medium was similar (36.23 and 34.57 mg/L respectively) for cells cultured with 1g glucose and 5 or 21% O2 conditions; lactate values were low (2.03 and 8,63 mg/L respectively) for 4.5 g glucose and 5 or 21% O2. Glucose uptake was not different whatever the culture conditions. These results indicate a low cellular respiration with a lactate production linked to the glucose concentrationin the medium, and raise the question of the capacity of chondrocytes to produce ROS in vivo starting from the mitochondrial chain. [less ▲]

Detailed reference viewed: 24 (1 ULg)
See detailEffects of O2 tension and glucose concentration on the cellular respiration of equine articular chondrocytes in culture.
Schneider, Nicole ULg; Lejeune, Jean-Philippe ULg; Mouithys-Mickalad, Ange ULg et al

Poster (2003)

In vivo, articular chondrocytes are exposed to 5 to 10% O21,2. Chondrocytes are also suspected to produce reactive oxygen species when submitted to anoxia/re-oxygenation3,4. We were interested to study ... [more ▼]

In vivo, articular chondrocytes are exposed to 5 to 10% O21,2. Chondrocytes are also suspected to produce reactive oxygen species when submitted to anoxia/re-oxygenation3,4. We were interested to study the effects of O2 and glucose variations on cellular respiration, glucose consumption and lactate production. Equine articular chondrocytes were cultured in suspension for 2 days under 5 or 21 % O2 in the gaseous phase, and with 0, 1.0 or 4.5 g/L glucose. The viable cells were then counted and the respiration rate (O2 consumption) of 10.106 cells was monitored by oxymetry for 2 hours; after oxymetry, glucose and lactate were measured in the medium (enzymatic assays). After 2 days, the cell viability was the best at 5% O2 and 1g/L glucose; it decreased at 4.5 g/L glucose and was the worst at 0g/L glucose, for the two O2 tensions (n=3). There was no obvious difference of the respiration rate between cells cultured at 5 and 21% O2, but respiration of chondrocytes was surprisingly low. When cells were submitted to 20 min anoxia at 0% O2, the O2 consumption was doubled at re-oxygenation for cells previously cultured at 21% O2. Glucose and lactate values found in the medium after oxymetry : lactate release in medium was similar (36.23 and 34.57 mg/L respectively) for cells cultured with 1g glucose and 5 or 21% O2 conditions; lactate values were low (2.03 and 8,63 mg/L respectively) for 4.5 g glucose and 5 or 21% O2. Glucose uptake was not different whatever the culture conditions. These results indicate a low cellular respiration with a lactate production linked to the glucose concentration in the medium, and raise the question of the capacity of chondrocytes to produce ROS in vivo starting from the mitochondrial chain. [less ▲]

Detailed reference viewed: 24 (1 ULg)
See detailOxidant activity of rabbit synoviocytes (HIG-82) demonstrated by oxymetry and ethylene production.
Schneider, Nicole ULg; Lejeune, Jean-Philippe ULg; Mouithys-Mickalad, Ange ULg et al

Poster (2003)

We are interested in a possible role of synoviocytes in the ROS production implicated in osteoarthritis, therefore we studied the response of a rabbit synoviocyte cell line (HIG-82) to variable oxygen ... [more ▼]

We are interested in a possible role of synoviocytes in the ROS production implicated in osteoarthritis, therefore we studied the response of a rabbit synoviocyte cell line (HIG-82) to variable oxygen tensions and the oxidant activity of these cells in response to stimuli. Synoviocytes were cultured at 5 and 21 % O2, their O2 consumption (cellular respiration, monitored with Clark electrode) was measured at 21% O2 and after anoxia, before and after stimulation with phorbol myristate acetate (PMA), and their oxidant response to PMA stimulation was quantified by measuring ethylene (gas chromatography) released when the substrate, alpha-keto-gamma-methylbutyric acid, is oxidised by the ROS produced by the cells. Cell growth was faster at 21 % O2 than at 5% O2, and microscopic observation revealed 2 cell populations: a few small round cells in suspension and many adherent cells. By oxymetry, we observed that a 106 synoviocytes suspension in 2 ml completely consumed O2 within 15 min, that anoxia (7 min) slightly slowed the respiration rate down and that PMA stimulation increased O2 consumption (150 % increase). The oxidant activity (ethylene production) of the cells was stimulated by PMA in a dose-dependent manner (10-9 to 10-7M) but the cell response was highly variable (from 150 to 1500 % increase) and was largely reduced by diphenyliodonium, an inhibitor of NADPH-oxidase and NO-synthase. The capacity to produce free radical species was confirmed for the small round cells by detection of an electron paramagnetic resonance (EPR) signal after stimulation. These results thus demonstrate a sensibility to O2 and an oxidant activity of synoviocytes at least related to ROS production by NADPH-oxidase activity. [less ▲]

Detailed reference viewed: 98 (2 ULg)
Full Text
Peer Reviewed
See detailJuvenile interphalangeal degenerative joint disease in the ardenner horse: morphometrical evaluation's protocol (part I)
Lejeune, Jean-Philippe ULg; Schneider, Nicole ULg; Duvivier, Dominique Hannia et al

in Annales de Médecine Vétérinaire (2002), 146(2, APR-MAY), 113-120

The observation of a high incidence of juvenile interphalangeal degenerative joint disease in ardenner horses motivated the constitution of a research project at the "Centre Europeen du Cheval de Mont-le ... [more ▼]

The observation of a high incidence of juvenile interphalangeal degenerative joint disease in ardenner horses motivated the constitution of a research project at the "Centre Europeen du Cheval de Mont-le-Soie" (Belgium). Its aim is to study the morphology of the horse, the conformation of its limbs as well as the potential outbreak and evolution of osteoarthritic lesions. Therefore an investigation method composed of morphometric and radiographic evaluation's protocols has been established. The morphometric evaluation's protocol presented here enables to characterise first the general morphology of the horse and second the foot, his asymmetries and his connections with the ground. This protocol is applied to 32 ardenner foals of 250 21 days of age. This group represents 9.3% of the births registered during the year 2000. For general morphometry, different values of the parameters are observed in this group. Only the higher size of the males makes the difference between the two populations (males and females) at this age. The morphometric study of the foot points out a widening of the external part of the hoof and an angle foot/ground too high in comparison with the established standards. Asymmetrical heights of hoof's quarters are also observed. [less ▲]

Detailed reference viewed: 54 (5 ULg)
Full Text
Peer Reviewed
See detailJuvenile interphalangeal degenerative joint disease in the ardenner horse: radiographical evaluation's protocol (part II)
Lejeune, Jean-Philippe ULg; Schneider, Nicole ULg; Duvivier, Dominique Hannia et al

in Annales de Médecine Vétérinaire (2002), 146(3, JUN-JUL), 173-179

Juvenile interphalangeal degenerative joint disease is frequently observed in ardenner horses. The aim of this study is to established a radiographic examination's protocol of the distal limb and to apply ... [more ▼]

Juvenile interphalangeal degenerative joint disease is frequently observed in ardenner horses. The aim of this study is to established a radiographic examination's protocol of the distal limb and to apply it to ardenner horses. This investigation method takes assess of the standings, the conformation and of the potential lesions of the digits. An essential point of this protocol is the quantification of the asymmetrical articular compression of the interphalangeal joints. Thirty-two ardenner foals of 250 +/- 21 days were radiographied. The most frequently observed anomalies are first, the existence of abnormal standings such as distal interphalangeal flexion and external articular compression of the interphalangeal joints. Second, it shows in some cases, an abnormal conformation of the second phalanx. Finally, this protocol points out the existence of juvenile degenerative joint disease and of ossification of the fibrocartilages in some foals at this age. [less ▲]

Detailed reference viewed: 58 (3 ULg)