References of "Lekeux, Pierre"
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See detailPulmonary Mechanics During Treadmill Exercise in Race Ponies
Art, Tatiana ULg; Lekeux, Pierre ULg

in Veterinary Research Communications (1988), 12(2-3), 245-258

Exercise-induced variations in their ventilatory mechanics were studied in 8 healthy ponies 4.2 +/- 1.4 years old and weighing 282 +/- 11 kg. Airflow (V), tidal volume (VT), esophageal pressure, mask ... [more ▼]

Exercise-induced variations in their ventilatory mechanics were studied in 8 healthy ponies 4.2 +/- 1.4 years old and weighing 282 +/- 11 kg. Airflow (V), tidal volume (VT), esophageal pressure, mask pressure and electrocardiogram were simultaneously recorded before, during and after a treadmill (incline 8.3 degrees) exercise which consisted of 2 min walking (1.5 m.sec-1), 3 min slow trotting (3.0 m.sec-1) and 3 min fast trotting (3.5 m.sec-1). The results of three consecutive daily measurements were averaged for each pony. Heart rate, minute volume (Ve), respiratory frequency (f) and peak inspiratory and expiratory V, mean inspiratory and expiratory V, and peak to peak changes in transpulmonary pressure (maxdPtp) increased linearly and significantly with increasing velocity (v) (R2 = 0.99). Tidal volume and the inspiratory time to total breathing time ratio showed a curvilinar relation with v (R2 = 0.99). Minute volume, maxdPtp, total pulmonary resistance (RL) and VT increased from rest to fast trot 6.7, 5.7, 1.5 and 1.6 times respectively. When the ponies stopped all these values decreased significantly. After 5 min recovery, the Ve was approximately doubled, VT and max dPtp unchanged and RL 30% smaller than their respective resting values. The exercise-induced increase in Ve was achieved by an increase in f at both low and high intensity of work. [less ▲]

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See detailA Critical Assessment of Pulmonary Function Testing in Exercising Ponies
Art, Tatiana ULg; Lekeux, Pierre ULg

in Veterinary Research Communications (1988), 12(1), 25-39

Pulmonary function measurements during exercise were tested for accuracy and reproducibility in 5 saddle ponies weighing 267 +/- 9 Kg. Airflow (V) and tidal volume (VT) were measured with a Fleisch ... [more ▼]

Pulmonary function measurements during exercise were tested for accuracy and reproducibility in 5 saddle ponies weighing 267 +/- 9 Kg. Airflow (V) and tidal volume (VT) were measured with a Fleisch pneumotachograph mounted on a face mask. The linearity of the response and the symmetry of this device were carefully checked. Pleural pressure changes were measured by pleural puncture (Ppl) and with an esophageal balloon catheter (Pes). The elastance of the esophageal wall and the effect of the position of the esophageal catheter tip on Pes were also investigated. Airflow, VT, Ppl, Pes, mask pressure, an electrocardiogram and limb movements were simultaneously recorded before, during and after exercise. These recordings were used to assess the validity of some pulmonary function measurements and to evaluate the influence of the breathing apparatus on the respiratory pattern. Maximal intrathoracic pressure changes and total pulmonary resistance values did not differ significantly when calculated on the basis of the Ppl and the Pes curves respectively. Although the absolute Ppl values were significantly different from the absolute Pes values, both pressures recorded at different workloads were closely correlated (R = 0.99). The mean specific elastance of the esophagus was 1.56 +/- 0.24 kPa.cm.ml.-1. Changes in the position of the esophageal catheter tip induced significant differences in the recorded Pes values. The pressure/flow relationship of the pneumotachograph pressure transducer system was linear within the range of the V measured during exercise. The mask had a significant influence on respiratory frequency and maximum difference in Pes, but did not modify the exercise-induced changes in these parameters. It was concluded that the technique and methods used in this study can allow accurate pulmonary function measurements in exercising ponies. [less ▲]

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See detailEffect of Environmental Temperature and Relative Humidity on Breathing Pattern and Heart Rate in Ponies During and after Standardised Exercise
Art, Tatiana ULg; Lekeux, Pierre ULg

in Veterinary Record : Journal of the British Veterinary Association (1988), 123(11), 295-299

A preliminary study attempted to assess the influence of atmospheric conditions on the breathing pattern of ponies. The respiratory airflow, tidal volume, breathing frequency, minute volume, total ... [more ▼]

A preliminary study attempted to assess the influence of atmospheric conditions on the breathing pattern of ponies. The respiratory airflow, tidal volume, breathing frequency, minute volume, total pulmonary resistance and heart rate of five ponies (257 +/- 9 kg and three to five years old) were measured by a standardised procedure. Data were collected at rest, during a nine minute period of treadmill exercise and during a five minute recovery period. The ambient temperature (degrees C) and relative humidity (%) were recorded at the time of each investigation and the respiratory parameters were divided into two groups according to whether the sum of these measurements was less than 85, ie, the conditions were cold and dry or greater than 85, ie, the conditions were relatively hot and humid. Data for each pony in both conditions were compared. The ambient temperature and relative humidity did not significantly modify the breathing pattern of the ponies either at rest or during exercise. On the other hand the frequency of breathing was significantly higher and the tidal volume and total pulmonary resistance were significantly lower during recovery in hot and humid conditions than in cold and dry conditions, while the minute volume remained unchanged. It was concluded that, during recovery, environmental conditions may modify the breathing pattern of horses. This suggests that in hot and humid weather conditions the respiratory rate may be an unreliable measure of the fitness of a horse and, consequently, that a more complete pulmonary investigation should be undertaken for an assessment of fitness. [less ▲]

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See detailMechanical work of breathing during treadmill exercise in ponies
Art, Tatiana ULg; Lekeux, Pierre ULg

in Archives Internationales de Physiologie et de Biochimie (1988), 96(5), 42

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See detailEffect of Enrofloxacin Therapy on Shipping Fever Pneumonia in Feedlot Cattle
Lekeux, Pierre ULg; Art, Tatiana ULg

in Veterinary Record : Journal of the British Veterinary Association (1988), 123(8), 205-207

The effect of enrofloxacin therapy was investigated in 110 male double-muscled cattle weighing 275 +/- 3 kg, during a spontaneous outbreak of shipping fever occurring 11 +/- 2 days after they arrived in ... [more ▼]

The effect of enrofloxacin therapy was investigated in 110 male double-muscled cattle weighing 275 +/- 3 kg, during a spontaneous outbreak of shipping fever occurring 11 +/- 2 days after they arrived in the feedlot. Forty-six diseased animals were divided randomly into three groups A, B and C, containing 17, 19 and 10 animals, respectively; the animals in group A were injected intramuscularly once daily for three consecutive days with 2.5 mg/kg of enrofloxacin, those in group B with 5 mg/kg of enrofloxacin and those in group C with 10 mg/kg of oxytetracycline. Clinical, serological, production and respiratory functional observations were recorded. The animals were clinically cured after the three day treatment except for three in group A and two in group C. These five animals made a clinical recovery after a three day booster treatment with a dose of 5 mg/kg enrofloxacin. The changes in respiratory gas exchange values induced by shipping fever were completely reversed 15 days later, suggesting that there had been no irreversible lung damage. The daily weight gains and the arterial blood gas values of the three groups of treated cattle were not significantly different. The high efficacy of the low dosage of enrofloxacin in this clinical syndrome may be explained by its antibacterial activity against Pasteurella species and Mycoplasma species. This field trial supports the in vitro studies which suggested than enrofloxacin is an appropriate therapy in cases of shipping fever. [less ▲]

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See detailThe effect of common bovine respiratory diseases on tidal breathing flow-volume loops
Lekeux, Pierre ULg; Art, Tatiana ULg; Amory, Hélène ULg

in Veterinary Research Communications (1988), 12(6), 463-473

In order to better understand the bovine breathing pattern, tidal breathing flow-volume loops (TBFVL) were analyzed in 24 healthy cattle of different body weights (range: 37-660 kg) (Group A) and in 28 ... [more ▼]

In order to better understand the bovine breathing pattern, tidal breathing flow-volume loops (TBFVL) were analyzed in 24 healthy cattle of different body weights (range: 37-660 kg) (Group A) and in 28 cattle suffering from the common respiratory diseases: verminous bronchitis (Group B); shipping fever (Group C); acute respiratory distress syndrome (Group D); respiratory syncytial virus pneumonia (Group E); organophosphate poisoning (Group F); and necrotic laryngitis (Group G). Respiratory airflow and tidal volume were measured with a breathing mask-Fleisch pneumotachograph assembly. TBFVL were traced from these values using a computerized method. All the loop indices proposed by Amis and Kurpershoek (1986a) were calculated from 5 representative breathing cycles for each of the 52 animals. The TBFVL shapes and indices were relatively constant in most healthy cattle and were not correlated with the body size. When compared to normal values, animals with moderate respiratory syndromes (Groups B and C) had a more flattened shape to their TBFVL. On the other hand, in most cattle with severe respiratory pathologies (Groups D, F and G expiration tended to be biphasic with the peak expiratory flow (PEF) occurring significantly later than in healthy animals. Both PEF and peak inspiratory flow were increased in all the pathological conditions. The TBFVL indices were more frequently and more severely changed during expiration than during inspiration. [less ▲]

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See detailA Comparison of Po2, Pco2, Ph and Bicarbonate in Blood from the Carotid and Coccygeal Arteries of Calves
Gustin, Pascal ULg; de Groote, A.; Dhem, A. R. et al

in Veterinary Research Communications (1988), 12(4-5), 343-346

A technique is described for the subcutaneous deviation of the carotid artery into the jugular groove of calves weighing between 90 and 200 kg. This makes sampling arterial blood or chronic cannulation ... [more ▼]

A technique is described for the subcutaneous deviation of the carotid artery into the jugular groove of calves weighing between 90 and 200 kg. This makes sampling arterial blood or chronic cannulation for further experimentation very easy. Values of oxygen tension, carbon dioxide tension, pH and bicarbonate concentration in blood sampled from the ventral coccygeal artery were compared with the values obtained in blood from carotid artery puncture. The high correlations observed indicate that blood samples from the ventral coccygeal artery can be used for measurement of blood gases and pH in calves. [less ▲]

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See detailSpécificités morphologiques et fonctionnelles du système respiratoire de la chèvre
Bakima, M.; Lekeux, Pierre ULg; Lomba, Fernand

in Annales de Médecine Vétérinaire (1988), 132

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See detailSpécificité de la fonction respiratoire des bovins dans des conditions physiologiques et pathologiques
Lekeux, Pierre ULg

in Bulletin de l'Académie Royale de Médecine de Belgique (1988), 143

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See detailInfluence of Inertance on Measurements of the Mechanical Properties of the Bovine Respiratory System
Lekeux, Pierre ULg; Art, Tatiana ULg; Clercx, Cécile ULg et al

in Veterinary Research Communications (1988), 12(1), 61-66

The observation that dynamic compliance (Cdyn) tended to rise with respiratory frequency (f) in adult cattle led us to reassess the importance of inertial pressures in measuring Cdyn in large animals ... [more ▼]

The observation that dynamic compliance (Cdyn) tended to rise with respiratory frequency (f) in adult cattle led us to reassess the importance of inertial pressures in measuring Cdyn in large animals. Five healthy Friesian cows were selected for their ability to show an increase of f without significant change in tidal volume (VT). Dynamic compliance was measured three times, both at the resting f (21 +/- 1 cpm), and at higher f (49 +/- 3 cpm), obtained by an artificial increase in the dead space of the breathing mask. Frequency-response characteristics of the measuring instruments were matched up to 12 Hz. The inertia of the lungs and gas stream (In) was calculated as the ratio of the accelerative pressure change to the simultaneous change in volume acceleration. Inertance was also estimated from the dimensions of the bovine airways and from the relative linear flow velocities reported by Rohrer (1915). Dynamic compliance measured during rapid breathing was significantly higher (p less than or equal to 0.01) than base-line values. Dynamic compliance was strongly correlated with f (r = +0.96). Measured and estimated In were 0.002 and 0.003 kPa.sec2.L-1 respectively. Dynamic compliance did not differ significantly from base-line values when it was corrected for the estimated inertance effect. [less ▲]

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See detailMeasurement of Total Respiratory Impedance in Calves by the Forced Oscillation Technique
Gustin, Pascal ULg; Dhem, A.R.; Lomba, Fernand et al

in Journal of Applied Physiology (Bethesda, Md. : 1985) (1988), 64(5), 1786-1791

We have determined the resistance (Rrs) and the reactance (Xrs) of the total respiratory system in unsedated spontaneously breathing calves at various frequencies. A pseudorandom noise pressure wave was ... [more ▼]

We have determined the resistance (Rrs) and the reactance (Xrs) of the total respiratory system in unsedated spontaneously breathing calves at various frequencies. A pseudorandom noise pressure wave was produced at the nostrils of the animals by means of a loudspeaker adapted to the nose by a tightly fitting mask. A Fourier analysis of the pressure in the nostrils and flow signals yielded mean Rrs and Xrs, over 16 s, at frequencies of 2-26 Hz. A good correlation was found between values of pulmonary resistances measured by the isovolume method at the respiratory frequency of animals and values obtained at a frequency of 6 Hz by use of our technique. The linearity of the respiratory system, the reproducibility of the technique, and the effects of upper airways on results have been studied. In healthy calves, Rrs increases with frequency. Mean resonant frequency is 7.5 Hz. Bronchospasm was induced in six calves by administration of intravenous organophosphates. Rrs tended to decrease with increasing frequency. Resonant frequency exceeded 26 Hz. All parameters returned to initial values after administration of atropine. In healthy calves, atropine produces a decrease in Rrs, especially at low frequencies. Values of resonant frequency are not modified. [less ▲]

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See detailInvestigation of the effects of histamine inhalation on the tracheobronchial tree of calves by the forced oscillation technique.
Gustin, Pascal ULg; Dhem, A.R.; Lekeux, Pierre ULg et al

in Journal of Veterinary Pharmacology & Therapeutics (1988), 11(4), 374-380

Effects of histamine inhalation were investigated with two different techniques in nine conscious, healthy calves. The oesophageal balloon technique was used to measure the dynamic respiratory compliance ... [more ▼]

Effects of histamine inhalation were investigated with two different techniques in nine conscious, healthy calves. The oesophageal balloon technique was used to measure the dynamic respiratory compliance (Cdyn) and the pulmonary resistance (RL). The reactance (Xrs) and the resistance (Rrs) of the respiratory system were measured at high frequencies by the forced oscillation technique. These parameters were recorded before and after histamine inhalation. Three histamine dihydrochloride solution concentrations were used (16 mg/ml; 32 mg/ml; 64 mg/ml). Histamine inhalation induced a decrease in Cdyn and Xrs an increase in Rrs, RL and of the resonant frequency and a negative frequency dependence of Rrs. Some of these changes were satisfactorily correlated with the histamine solution concentrations. The resonant frequency was well correlated with Cdyn. It was concluded that histamine inhalation induces a decrease of the calibre of small and large airways and a non-homogeneous behaviour of the pulmonary ventilation in awake calves. The forced oscillation technique can be used to perform an inhalation provocation test in unsedated animals. [less ▲]

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See detailOxygen Transport Properties of Blood in Two Different Bovine Breeds
Gustin, Pascal ULg; Clerbaux, T.; Willems, Evelyne ULg et al

in Comparative Biochemistry and Physiology. A : Comparative Physiology (1988), 89(4), 553-558

1. The whole oxygen dissociation curve of oxyhemoglobin has been determined in double-muscled cattle of the Belgian White Blue breed and in Friesian cattle of different body weight. 2. In calves, P50 ... [more ▼]

1. The whole oxygen dissociation curve of oxyhemoglobin has been determined in double-muscled cattle of the Belgian White Blue breed and in Friesian cattle of different body weight. 2. In calves, P50 values are low and DPG level is high (4-20 mumol/g Hb). 3. P50 values of 25 +/- 1.4 mm Hg (mean +/- SD) and a level of DPG less than 1.5 mumol/g Hb have been found in animals weighing more than 80 kg. 4. Effects of temperature and pH on the oxygen dissociation curve have been measured at all levels of saturation. The temperature coefficient (dlog P50/dT) and the Bohr effect expressed as dlog P50/dpH were 0.017 and -0.40, respectively. 5. Hematocrit, hemoglobin concentrations and oxygen capacity of hemoglobin have been measured. 6. No difference between both breeds has been observed. 7. These data can be used to correct measured values of oxygen tension for temperature and pH and to measure oxygen content of blood in cattle. [less ▲]

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See detailTechniques d'investigation de la fonction cardiaque chez les animaux domestiques
Amory, Hélène ULg; Art, Tatiana ULg; Lekeux, Pierre ULg

in Annales de Médecine Vétérinaire (1988), 132

Une revue des techniques d'investigation du coeur a été réalisée d'un point de vue morphologique, électrique, fonctionnel et métabolique. Un accent particulier a été posé sur celles de ces techniques qui ... [more ▼]

Une revue des techniques d'investigation du coeur a été réalisée d'un point de vue morphologique, électrique, fonctionnel et métabolique. Un accent particulier a été posé sur celles de ces techniques qui ont connu, au cours des dernières années, une expansion importante en médecine vétérinaire [less ▲]

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See detailCould pulmonary inertance be a limiting factor of ventilation during exercise in the equine species ?
Art, Tatiana ULg; Lekeux, Pierre ULg; Gustin, Pascal ULg et al

in Proceedings of the 7th Comparative Respiratory Society Meeting (1988)

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See detailStudy of the airflow patterns in healthy and diseased cattle
Lekeux, Pierre ULg; Art, Tatiana ULg

in Proceedings of the Sixth Veterinary Respiratory Symposium (1987, November)

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See detailMechanics of breathing and gas exchanges in healthy cattle: effect of somatic growth
Lekeux, Pierre ULg

in Archives Internationales de Physiologie et de Biochimie (1987, November), 95(2), 5

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See detailFunctional Changes Induced by Necrotic Laryngitis in Double Muscled Calves
Lekeux, Pierre ULg; Art, Tatiana ULg

in Veterinary Record : Journal of the British Veterinary Association (1987), 121(15), 353-355

The effects of necrotic laryngitis on the mechanics of breathing and gas exchange were investigated in five Belgian blue double muscled calves two to three months old. All the animals showed the typical ... [more ▼]

The effects of necrotic laryngitis on the mechanics of breathing and gas exchange were investigated in five Belgian blue double muscled calves two to three months old. All the animals showed the typical clinical picture of the respiratory syndrome associated with naturally occurring necrotic laryngitis. Highly significant increases in total pulmonary resistance, minute viscous work of breathing and alveolar-arterial oxygen gradient, and highly significant decreases in dynamic lung compliance and arterial oxygen tension were recorded in the infected animals, when compared to reference values for healthy cattle. The ratio of inspiratory to expiratory viscous work of breathing was also significantly increased probably because of a partial collapse of the extrathoracic trachea during inspiration. It was concluded that necrotic laryngitis disturbs pulmonary function to such an extent that it impedes the growing process and predisposes the infected animals to secondary bronchopneumonia and ventilatory failure due to respiratory muscle fatigue. [less ▲]

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See detailPartitioning of pulmonary resistance in calves
Gustin, Pascal ULg; Lomba, F.; Bakima, J. et al

in Journal of Applied Physiology (Bethesda, Md. : 1985) (1987), 62(5), 1826-1831

Nine right apical lobes of healthy Friesian calves and 10 right apical lobes of double-muscled calves of Belgian White and Blue (BWB) breed were suspended in an airtight box, inflated at a constant ... [more ▼]

Nine right apical lobes of healthy Friesian calves and 10 right apical lobes of double-muscled calves of Belgian White and Blue (BWB) breed were suspended in an airtight box, inflated at a constant transpulmonary pressure (Ptp), and subjected to quasi-sinusoidal pressure changes (amplitude: 0.5 kPa) at a frequency of 30 cycles/min. Lobar resistance (RL) was partitioned at six different lung volumes into three components: central airway resistance (Rc), small airway resistance (Rp), and tissue resistance (Rt). Pressure in small airways (2-3 mm ID) was measured with a retrograde catheter. Alveolar pressure was sampled in capsules glued onto the punctured pleural surface. RL was minimal at values of Ptp comprised between 0.5 and 0.7 kPa and increased at higher and lower values of Ptp. At a Ptp of 0.5 kPa, Rc, Rp, and Rt represented 30, 15, and 55% of RL, respectively, in Friesian calves and 25, 25, and 50% in BWB calves. Rp increased markedly at low lung volumes. Rt was responsible for the increase of RL at high Ptp. Rc tended to decrease at high Ptp. The significantly higher values of Rp in BWB calves (P less than 0.05) might explain the sensitivity of this breed to severe bronchopneumonia [less ▲]

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