References of "Lekeux, Pierre"
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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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See detailInertance pressures and their implications in pulmonary function testing in cattle
Lekeux, Pierre ULg; Art, Tatiana ULg

in Archives Internationales de Physiologie et de Biochimie (1987), 95(4), 74

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

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

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See detailEffet des pathologies respiratoires sur la fonction pulmonaire des bovins à l'engraissement
Lekeux, Pierre ULg; Art, Tatiana ULg; Gustin, Pascal ULg et al

in Annales de Médecine Vétérinaire (1987), 131

Clinical, serological and physiological values were measured during and after naturally occuring respiratory disease in fattening cattle. Clinical and serological findings were in agreement with the ... [more ▼]

Clinical, serological and physiological values were measured during and after naturally occuring respiratory disease in fattening cattle. Clinical and serological findings were in agreement with the description of the Shipping Fever syndrome. Pulmonary function values recorded during the initial stage of the disease showed a significant increase in respiratory rate, total pulmonary resistance, minute viscous work of breathing and alveolo-arterial oxygen gradient and a significant decrease in tidal volume and arterial oxygen tension. None of these values was still abnormal 2 weeks later. It was concluded that moderate Shipping Fever induce an acute obstructive disease located mainly at the level of large airways. On the other hand, the complete reversibility of the clinical and functional changes indicates that accurate preventive and curative treatments may avoid the onset of severe pulmonary dammage and may reduce the economical losses induced by the Shipping Fever syndrome. [less ▲]

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See detailFunktioneller Zugang zu den Respirationskrankheiten der Doppellender-Rinder der Rasse Weiss-Blaue Belgier.
Gustin, Pascal ULg; Bakima, M.; Lekeux, Pierre ULg et al

in Deutsche Tierarztliche Wochenschrift (1987), 94(5), 261-264

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See detailMechanical properties of excised calf lungs: effects of airway obstruction with beads
Gustin, Pascal ULg; Lekeux, Pierre ULg; Lomba, F. et al

in Research in Veterinary Science (1987), 42(3), 277-279

Isolated lungs of five calves were suspended in an airtight box used as a ventilator. Lungs were ventilated from the outside at different levels of transpulmonary pressure. Dynamic compliance (Cdyn) and ... [more ▼]

Isolated lungs of five calves were suspended in an airtight box used as a ventilator. Lungs were ventilated from the outside at different levels of transpulmonary pressure. Dynamic compliance (Cdyn) and total pulmonary resistance (RL) were measured. These pulmonary function values were also measured during central and peripheral airway obstructions. It was demonstrated that both central and peripheral obstructions induced significant variations of Cdyn and RL. However, decrease of Cdyn was greater and increase of RL was smaller during a peripheral obstruction than during a central one [less ▲]

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See detailMechanical properties of excised calf lungs
Gustin, Pascal ULg; Lekeux, Pierre ULg; Lomba, F. et al

in Research in Veterinary Science (1987), 42(3), 272-276

Five isolated calf lungs were suspended in an airtight box used as a ventilator. Lungs were ventilated from the outside at different levels of transpulmonary pressure (Ptp). The static pressure-volume ... [more ▼]

Five isolated calf lungs were suspended in an airtight box used as a ventilator. Lungs were ventilated from the outside at different levels of transpulmonary pressure (Ptp). The static pressure-volume curve characteristics of the lungs were measured. Static compliance (Cstat) was 1.9 +/- 0.37 litres kPa-1 or 25 +/- 5 per cent of total lung capacity kPa-1. At a Ptp of 0.7 kPa, dynamic compliance (Cdyn) and lung resistance (RL) were 1.1 +/- 0.1 litres kPa-1 and 0.126 +/- 0.02 kPa litres sec-1, respectively. Both an increase and a decrease of this level of Ptp induced an increase of RL and a decrease of Cdyn. The ratio Cdyn/Cstat averaged 57 +/- 0.8 per cent. It was concluded that in excised lungs, Cdyn is lower in the calf than in a number of other species and that pulmonary function values measured in vitro are optimum at values of Ptp close to values recorded in vivo in healthy cattle [less ▲]

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See detailPartitioning of pulmonary resistance in Friesian calves
Gustin, Pascal ULg; Bakima, M.; Lekeux, Pierre ULg et al

in Research in Veterinary Science (1987), 42(3), 313-317

Eight right cranial lobes of healthy Friesian calves were suspended in an airtight box. They were inflated at a constant transpulmonary pressure (Ptp) and ventilated from the outside by modifying ... [more ▼]

Eight right cranial lobes of healthy Friesian calves were suspended in an airtight box. They were inflated at a constant transpulmonary pressure (Ptp) and ventilated from the outside by modifying pressures in the box with a quasi-sinusoidal pump at a frequency of 30 counts per minute. Peak-to-peak changes were 0.5 kPa. Lobar resistance (Rl) was partitioned into three components: central airway resistance (Rc), small airway resistance (Rp) and tissue resistance (Rt). Partitioning of R1 was realised at six different lung volumes. Minimal R1 was observed for a value of Ptp between 0.5 and 0.7 kPa. At a Ptp of 0.5 kPa, Rc, Rp, Rt represent 30, 15 and 55 per cent of R1, respectively. Lobar resistance increases at high and low lung volumes. Small airway resistance is small and independent of the level of lung inflation, except at low lung volumes where a marked increase is observed. Tissue resistance is relatively high and responsible for the increase of R1 at high lung volumes. Central airway resistance does not change significantly with lung volumes [less ▲]

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See detailPartitioning of upper airway resistance in Friesian and double-muscled calves.
Gustin, Pascal ULg; Bakima, M.; Lekeux, Pierre ULg et al

in Respiration Physiology (1987), 69(3), 299-306

Respiratory resistance in calves was partitioned in two components: upper airway resistance and pulmonary resistance. The former one was divided into naso-pharyngeal and laryngeal resistance. A comparison ... [more ▼]

Respiratory resistance in calves was partitioned in two components: upper airway resistance and pulmonary resistance. The former one was divided into naso-pharyngeal and laryngeal resistance. A comparison between seven healthy unsedated double-muscled calves of the Belgian White and Blue breed (BWB) and five healthy unsedated Friesian (F) calves was performed. Respiratory resistance was significantly greater in the BWB calves, due to the significantly higher values of the naso-pharyngeal and the laryngeal resistances. This finding might be related to the higher prevalence of laryngitis in this breed [less ▲]

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See detailPulmonary function and tracheal dynamics during upper airway obstructive diseases in cattle
Lekeux, Pierre ULg; Art, Tatiana ULg

in Proceedings of the Fifth Veterinary Respiratory Symposium (1986, November 15)

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See detailEfficacy of ivermectin and levamisole against immature Dictyocaulus viviparus in cattle
Pouplard, L.; Lekeux, Pierre ULg; Detry, M.

in Veterinary Record : Journal of the British Veterinary Association (1986), 118

Eighteen calves aged approximately three months were each infected with Dictyocaulus viviparus larvae at a rate of 30/kg bodyweight. Seven days later they were randomly allocated to three groups of six ... [more ▼]

Eighteen calves aged approximately three months were each infected with Dictyocaulus viviparus larvae at a rate of 30/kg bodyweight. Seven days later they were randomly allocated to three groups of six animals. Calves of group 1 were controls. Calves of group 2 were given levamisole at a dose rate of 10 mg/kg and calves of group 3 were given ivermectin at a dose rate of 200 micrograms/kg. The anthelmintic activity of these two drugs was compared using clinical, functional, parasitological and pathological parameters. The results showed that the efficacy of ivermectin, given at a therapeutic dose, against immature D viviparus was higher than that of levamisole, given at double the recommended dose [less ▲]

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