Affections musculaires et intolrance à l'effort. 1- Pathogénie et approche diagnostique

in Pratique Vétérinaire Equine (2000), 32

The muscular condition, rhabdomyolysis, may cause exercise intolerance in the sporting horse. When the condition is recurring, it is often difficult for the equine practitioner to establish the clinical ... [more ▼]

The muscular condition, rhabdomyolysis, may cause exercise intolerance in the sporting horse. When the condition is recurring, it is often difficult for the equine practitioner to establish the clinical diagnosis (is the horse suffering from rhabdomyolysis or not ?) and the aetiology (what is/are the cause(s) of the condition ?) and also to provide an effective treatment [less ▲]

Influence of ventilatory pattern on respiratory impedance measured by impulse oscillometry in horses

in Pflügers Archiv : European Journal of Physiology (2000), 440(R219-R220),

Assessment of muscle oxygenation in the horse by near infrared spectroscopy

in Equine Veterinary Journal (2000), 32(1), 59-64

This study examined the ability of near infrared spectroscopy (NIRS) to noninvasively determine changes to muscle oxygenation in the resting horse. Five horses had (NIRS) performed over extremity muscle ... [more ▼]

This study examined the ability of near infrared spectroscopy (NIRS) to noninvasively determine changes to muscle oxygenation in the resting horse. Five horses had (NIRS) performed over extremity muscle while under general anaesthesia, first with 8 min limb ischaemia, then systemic hypoxaemia for 5 min. A second group of 6 awake horses had NIRS performed over extremity muscle while being administered hypoxic gas (F(I)O2 0.10) for 5 min, and after return to steady state, limb ischaemia was induced for an additional 5 min. In the anaesthetised horses' ischaemia induced marked and significant muscle deoxygenation of haemoglobin/myoglobin (P<0.01), with corresponding arterial saturation decreasing from 98.9 to 81.9%. Hypoxaemia induced small yet significant muscle deoxygenation (P<0.01) that was 3.2% of the ischaemia deoxygenation signal, with a corresponding decrease in arterial saturation from 98.6 to 90.4%. In the awake horses muscle deoxygenation was not detectable during hypoxia despite reduction of arterial saturation from 97.8 to 86.8%, whereas ischaemia induced rapid and significant deoxygenation of muscle (P<0.05), with corresponding reduction of venous saturation from 78.4 to 75.4%. In neither group of horses was there evidence of cytochrome aa3 reduction, despite complete ischaemia for up to 8 min. NIRS changes in the resting horse muscle clearly differed between ischaemia and hypoxaemia, and can readily show muscle deoxygenation in clinically relevant hypoxaemia in the horse under anaesthesia. Further, as the deoxygenation signal induced by ischaemia was clearly detectable above a background movement artefact, NIRS application to study of muscle oxygenation in the working horse should be explored. [less ▲]

Affections cardiaques et intolérances à l'effort. 2-Les souffles.

in Pratique Vétérinaire Equine (2000), 32(Numéro Spécial), 79-86

Bronchial hyperrespponsiveness to isoprostanes in an animal model of asthma

in Pflügers Archiv : European Journal of Physiology (2000), 439(R242),

Effect of hyonate administration on pulmonary function and indices of oxidative stress in COPD horses in clinical remission at rest and after exercise

in Journal of Equine Veterinary Science (1999), 19

Pulmonary function tests, bronchoalveolar lavages, and venous blood samplings were performed 24 hours before and one hour after a standardized strenous treadmill exercise test on six horses suffering from ... [more ▼]

Pulmonary function tests, bronchoalveolar lavages, and venous blood samplings were performed 24 hours before and one hour after a standardized strenous treadmill exercise test on six horses suffering from chronic obstructive pulmonary disease (COPD) in clinical remission. Pulmonary function test consisted of the measurement of the mechanics of breathing and arterial blood gases analyses. During the exercise tests, heart and respiratory rates, and venous plasma lactate, pH and packed cell volume were controlled. Venous blood was analyzed for some markers of the oxidative stress, i.e., hemolysate glutathione redox ratio and oxidized glutathione, and plasma uric acid. BAL was analyzed for cell cytology as well as for markers of oxidative stress, i.e., glutathione redox ratio, and isoprostanes concentration. The procedure was repeated twice, i.e., before and after two IV injections of 40mg hyaluronate administered at seven day intervals. The results were compared to assess a possible influence of the treatment on the pulmonary and systemic inflammatory and/or oxidative status of these horses. Hyaluronate did not influence the pulmonary function test or the physiological parameters recorded during exercise. There was a decrease in the percentage of BAL neutrophils after the treatment, suggesting a possible anti-inflammatory effect at the pulmonary level. As well, the concentration of isoprostanes in the pulmonary epithelium lining fluid was significantly lower after the treatment, which might be either a consequence of the decrease of the BAL neutrophils, or related to a possible antioxidant effect of the treatment. Lastly, the exercise-induced increase in plasma uric acid was significantly less marked after the treatment, which could be due to a systemic antioxidant effect of the hyaluronate. In conclusion, this preliminary study brings some evidence that hyaluronate could have some antiinflammatory and antioxidant effects at the pulmonary—and systemic—level in COPD horses in remission. However, it does not help to understand the possible mechanisms underlying these observations. Further studies are now necessary to better understand its action, to assess the effect of the product on the pulmonary function of horses suffering from other respiratory problems as well as to assess the efficiency of other ways of administration, i.e., nebulization [less ▲]

Inhalation therapy of equine respiratory disorders

in Equine Veterinary Education (1999), 11(3), 124-130

Cardiorespiratory measurements and indices of oxidative stress in exercising COPD horses

in Equine Veterinary Journal. Supplement (1999), 30

The effect of a COPD crisis on arterial blood gases, heart rate, lactate and indices of oxidative stress were investigated before, during and 1 h after a 'run up to fatigue' in 6 COPD horses. They were ... [more ▼]

The effect of a COPD crisis on arterial blood gases, heart rate, lactate and indices of oxidative stress were investigated before, during and 1 h after a 'run up to fatigue' in 6 COPD horses. They were investigated twice, randomly: once in acute crisis (C) and once in clinical remission (R). Arterial and mixed venous blood samples were collected and analysed for partial pressures in O2 and CO2. The mixed venous blood was also analysed for plasma lactate (LA) and packed cell volume (PCV), as well as for indices of oxidative stress, i.e. reduced glutathione, glutathione disulphide, glutathione redox ratio (GRR) and lipid hydroperoxides (LPH). The exercise test was an effort of increasing intensity on a treadmill at 0% slope, which was stopped when the horses showed signs of exhaustion. Their performance was evaluated by the number of steps and the running time in the last step. Heart rate was monitored continuously during the test. Blood sampling was performed before, just after and 1 h after the end of the test. The COPD crisis significantly reduced the time to fatigue. However, despite the fact that the exercise intensity and length were lower, peak HR and peak LA were similar in C and R, while arterial hypoxaemia and hypercapnia, and PCV were significantly higher in C, indicating a higher physiological stress in this condition. By contrast, the oxidative stress seemed to be higher in R than in C as suggested by the fact that, 1 h after exercise, GRR and LPH were significantly increased with regards to their pre-exercise values in R and not in C. The fact that exercise did not induce an oxidative stress in C could be partly related to (1) the lower exercise intensity reached by the horses, and (2) to the more severe hypoxaemia experienced in this condition. In conclusion, COPD horses in acute crisis show a significant decrease in performance. The reasons for this exercise intolerance remain unclear, but do not appear to be related to any increase of the oxidative stress in C. [less ▲]

Analysis of Scintigraphical Lung Images before and after Treatment of Horses Suffering from Chronic Pulmonary Disease

in Veterinary Record : Journal of the British Veterinary Association (1999), 144(9), 232-236

Scintigraphical analysis of the ratio of inhalation (I) to perfusion (Q) was designed to determine whether chronic pulmonary disease in horses induced mismatches in I/Q and to assess whether medical ... [more ▼]

Scintigraphical analysis of the ratio of inhalation (I) to perfusion (Q) was designed to determine whether chronic pulmonary disease in horses induced mismatches in I/Q and to assess whether medical treatment would restore an I/Q distribution pattern identical to that of control horses. In addition, the results of the I/Q analysis were correlated with the alveolar-arterial PO2 difference (AaDO2). The I/Q matching found in a group of control horses was compared with the I/Q analysis of a group of diseased horses before and after their clinical signs had been treated. The analysis indicated that there was mismatching between I and Q before they were treated. The treatment improved the diseased horses, pulmonary function but there was still heterogeneity in the I/Q distribution after they had been treated. The I/Q analysis parameters were well correlated with the ratio of ventilation (VA) and pulmonary blood flow (Q), evaluated by the determination of AaDO2 [less ▲]

Effects of inhaled dry powderipratropium broide on reconvery from exercise of horses with COPD

in Equine Veterinary Journal (1999), 31(1), 20-24

The present study evaluated ventilatory, cardiovascular and metabolic parameters during recovery from strenuous exercise in horses suffering from a crisis of chronic obstructive pulmonary disease (COPD ... [more ▼]

The present study evaluated ventilatory, cardiovascular and metabolic parameters during recovery from strenuous exercise in horses suffering from a crisis of chronic obstructive pulmonary disease (COPD) and to determine whether ipratropium dry powder inhalation (DPI) before exercise has an effect on these parameters. When 6 saddle horses, affected with COPD, developed airway obstruction, they inhaled placebo and ipratropium (2400 pghorse), the order being randomly chosen. Pulmonary function tests were then recorded 15 min after inhalation. Following these tests, the horses underwent a strenuous treadmill exercise, followed by a ecovery period that consisted of a 10 min walk. Measurements were made at the first and tenth min of recovery. Respiratory flow, 0 2 and C02 fractions in the respired gas, pleural pressure changes and heart rate were recorded. Arterial and mixed venous blood samples were analysed or gas tensions, haemoglobin and plasma lactate concentrations. Oxygen consumption (Wz), C02 production, tidal volume, alveolar oxygen tension (PAOz), alveolar ventilation, the alveolar-pulmonary capillary oxygen difference ((A-a)dOz) and total pulmonary resistance (RL) were measured. The PA02 was the only parameter significantly improved during recovery following ipratropium DPI. This improvement was not accompanied by evidence of improvement of other ventilatory or cardiorespiratory parameters. The results showed that in horses suffering from a crisis of COPD, recovery is characterised by an exercise-induced bronchodilation. Secondly, ipratropium DPI at a dose of 2400 pghorse is an effective bronchoddator in these horses at rest but it has little effect on the airway calibre during the recovery period. It is suggested that the short term recovery period is still Muenced by exercise-induced adjustments that may exceed the bronchodilatory effect of inhaled ipratropium that are observed before exercise [less ▲]