Effect of cross country on plasma levels of myeloperoxidase in saddle ponies

in Abstracts book of iceep (2006)

Degenerative osteoarthropathy in horses: pathogeny and diagnostic

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 ▲]

Evaluation of biochemical bone markers in Ardenner horses: comparison between sound horses and horses with juvenile form of interphalangeal joint disease

Poster (2006)

Synoviocytes, not chondrocytes, release free radicals after cycles of anoxia/re-oxygenation

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 ▲]

Resveratrol and curcumin reduce the respiratory burst of Chlamydia-primed THP-1 cells

in Biochemical and Biophysical Research Communications (2005), 333(1), 21-27

The intracellular bacterium Chlamydia pneumoniae is involved in the inflammation process of atherosclerosis. We previously demonstrated that C. pneumonia infected monocytes (THP-1 cells) responded to ... [more ▼]

The intracellular bacterium Chlamydia pneumoniae is involved in the inflammation process of atherosclerosis. We previously demonstrated that C. pneumonia infected monocytes (THP-1 cells) responded to stimulation by an increased respiratory burst linked to an increased NADPH oxidase (NOX) activity. We now tested agents acting on the assembly of the NOX subunits or on protein kinase C, a trigger of NOX activity. Apocynin, resveratrol, rutin, quercetin, curcumin, and tocopherols were tested. The cells were pre-incubated with Chlamydia and the agent for 19 h, and then stimulated with phorbol myristate acetate. The NOX activity was monitored by measuring the hydrogen peroxide production. Resveratrol and curcumin (10(-4)-10(-6) M) were better inhibitors than apocynin. alpha-Tocopherol was inactive, and gamma-tocopherol inhibitor at 10(-4) M only. Quercetin was inactive, and rutin a moderate but significant inhibitor. The inhibition by resveratrol was increased by 10(-6) M rutin or quercetin. Resveratrol and curcumin thus appeared to be interesting for atherosclerosis treatment. [less ▲]

Does Acepromazine reduce the cardiovascular toxicity of Norepinephrine in the horse

in Proceedings of the Congress of Veterinary Anesthesia (2005)

SYNOVIOCYTES BUT NOT ARTICULAR CHONDROCYTES RELEASE FREE RADICALS AFTER REPETITIVE CYCLES OF ANOXIA/REOXYGENATION: AN ELECTRON SPIN RESONANCE STUDY.

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 ▲]

Design of an ELISA specific for the measurement of equine neutrophil myeloperoxidase in biological fluids

in Clinical Chemistry (2005), 51(Suppl. 6), 211-212

Hyperhydricity of Prunus avium shoots cultured on gelrite: a controlled stress response

in Plant Physiology & Biochemistry (2004), 42(6), 519-527

Hyperhydricity is a physiological disorder frequently affecting shoots vegetatively propagated in vitro. Hyperhydric shoots are characterised by a translucent aspect due to a chlorophyll deficiency, a not ... [more ▼]

Hyperhydricity is a physiological disorder frequently affecting shoots vegetatively propagated in vitro. Hyperhydric shoots are characterised by a translucent aspect due to a chlorophyll deficiency, a not very developed cell wall and a high water content. Hyperhydricity of Prunus avium shoots was expressed in vitro in one multiplication cycle by replacing the gelling agent agar (normal shoots: NS) by gelrite (hyperhydric shoots: HS). P. avium shoots evolving towards the hyperhydric state produced higher amounts of ethylene, polyamines (PAs) and proline, which are substances considered as stress markers. A higher activity of glutathione peroxidase (GPX; EC 1.11.1.9), involved in organic hydroperoxide elimination, suggested an increased production of these compounds in HS. The unchanged free fatty acid composition indicated no HS membrane damages compared to NS. The ploidy level of HS nuclei was not affected, but the bigger size and the lower percentage of nuclei during the S phase suggested a slowing down of the cell cycle. The results argued for a stress response of the HS, but no signs of oxidative damages of lipid membrane and nucleus were observed. The discussion points out paradoxical results in a classical analysis of stress and suggests an alternative way of defense mechanisms in HS, involving homeostatic regulation and controlled degradation processes to maintain integrity and vital functions of the cell. (C) 2004 Elsevier SAS. All rights reserved. [less ▲]

Investigation on prenatal endocrinology: preliminary results on long term catheterisation of bovine foetuses

in Reproduction (Cambridge, England). Abstract Series (2004), 31