References of "Desmecht, Daniel"
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See detailThe relation of ventilatory failure to pulmonary, respiratory muscle and central nervous system disturbances in calves with an experimentally produced pneumonia
Desmecht, Daniel ULg; Linden, Annick ULg; Lekeux, Pierre ULg

in Journal of Comparative Pathology (1996), 115(3), 203-219

To explore the pathophysiology of respiratory failure in an experimental pneumonia, a Pasteurella haemolytica broth culture was injected intratracheally into 12 calves, which were then studied over a ... [more ▼]

To explore the pathophysiology of respiratory failure in an experimental pneumonia, a Pasteurella haemolytica broth culture was injected intratracheally into 12 calves, which were then studied over a period of 10 h. Measurements were made of inspired minute ventilation VE), ventilatory pattern [inspiratory time (TI), expiratory time (TE), respiratory rate (RR) and tidal volume (VT)], transdiaphragmatic pressure (Pdi), occlusion pressure at the airway opening 100 milliseconds after onset of inspiration (Pawo100ms), arterial blood gas tensions and pH and recorded diaphragmatic electromyogram (EMGdi) and rectal temperature (Tr). On and after the third hour after inoculation, the animals varied in respect of clinical signs, Tr, RR, VE, Pawo100ms/EMGdi, and arterial gases and pH. In benign cases, diminished alertness, laboured respiration and fall of arterial oxygen pressure (PaO2) worsened up to 7 h after inoculation, but then progressively improved, VE being maintained at approximately 150% baseline throughout the study (10 h). Neither arterial carbon dioxide pressure (PaCO2) nor pH was altered. Moderate cases resembled benign cases in respect of laboured respiration, VE, PaO2 and PaCO2; however, pH was at first maintained at preinoculation levels, but declined thereafter. In severe cases, the animals were drowsy between hours 3 and 7, and became comatose between hours 8 and 10; in contrast to both benign and moderate cases: (1) RR was reduced by hour 5, (2) there was no trend towards recovery of PaO2 and pH, (3) VE, Pdi, Pawo100ms and Pawo100ms/EMGdi were severely decreased, and (4) PaCO2 increased. These results suggest that pneumonia does not alter ventilatory neuromuscular pump function in calves, unless concomitant cardiovascular collapse occurs. It is not clear whether fatal ventilatory failure is caused mainly by deterioration in ventilatory muscle fibre processes or structures, altered central nervous system adjustment of ventilatory timing, or cardiovascular dysfunction. However, inspiratory pressures fall when excitation to the diaphragm is still growing, which suggests peripheral respiratory muscle fatigue. [less ▲]

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See detailControl of breathing in healthy and pasteurella-exposed calves after 5-HT receptor blockade
Rollin, Frédéric ULg; Close, R; Linden, Annick ULg et al

in Proceedings of the XIXth World Association for Buiatrics Congress (1996)

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See detailProphylactic activity of metrenperone-MDL 72222 association in calves given intravenous 3-methyl-indole
Desmecht, Daniel ULg; Linden, Annick ULg; Lekeux, Pierre ULg

in Pflügers Archiv : European Journal of Physiology (1996), 431

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See detailHaemodynamic dysfunctions involved in experimental bovine pneumonic pasteurellosis
Desmecht, Daniel ULg; Amory, Hélène ULg; Linden, Annick ULg et al

in Journal of Experimental Animal Science (1996), 37

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See detailRuminal, cardiorespiratory and adrenocortical sequelae of Na2EDTA-induced hypocalcemia in calves
Desmecht, Daniel ULg; Linden, Annick ULg; Lekeux, Pierre ULg

in Veterinary Research Communications (1996), 20

A study was undertaken to provide further information on the ruminal, cardiorespiratory and hypothalamo-pituitary-adrenocortical (HPAC) physiological sequelae of hypocalcaemia in dairy calves. The ... [more ▼]

A study was undertaken to provide further information on the ruminal, cardiorespiratory and hypothalamo-pituitary-adrenocortical (HPAC) physiological sequelae of hypocalcaemia in dairy calves. The functional picture observed in standing calves experiencing Na2EDTA-induced progressive hypocalcaemia showed a biphasic pattern. During the first phase (Ca2+ varying between 1.20 +/- 0.09 and 0.64 +/- 0.15 mmol/L, mean +/- SD), the animals became dull and lethargic, shifting their weight from one hind limb to the other, with cool extremities and hypersalivation. Their ventilation was slightly increased but their heart rate, thoracoabdominal pressure, pulmonary mechanics, haemoglobin and temperature remained constant. Conversely, their systemic arterial pressure (SAP) and the amplitude of their ruminal contractions (RCA) were severely decreased. During the second phase (Ca2+ < 0.64 +/- 0.15 mmol/L), there was restlessness, tachycardia, hypertension, polycythaemia and, finally, inability to stay upright. It is suggested that the diminished Ca2+ availability caused smooth-muscle and myocardial dysfunctions which could explain the RCA and SAP changes recorded during the first phase, whereas neural and/or humoral sympathetic discharge probably accounted for the reversal in SAP and heart rate when Ca2+ was decreased further. Serum cortisol increased regularly and remained significantly correlated with Ca2+ in each animal. Moreover, regression of delta cortisol/delta Ca2+ on delta Ca2+/delta Na2EDTA was significant (p < or = 0.001). It was concluded that mild asymptomatic hypocalcaemia severely impairs ruminal function, which will progressively worsen the Ca2+ deficit; that the inability to maintain posture in hypocalcaemia is not due to hypotension; and that the higher the HPAC response to hypocalcaemia, the higher the resistance to its effects. An asymptomatic periparturient cow with barely detectable ruminal activity may merit preventive calcium borogluconate therapy. Also, the physiological role of hypotension in explaining the clinical picture may be less important than other processes, such as neuromuscular failure. Finally, the present results imply a possible HPAC exhaustion in cows with periparturient paretic hypocalcaemia [less ▲]

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See detailElectrophysiologic evaluation of the phrenic nerve-diaphragm pathway in an intact conscious calf model
Desmecht, Daniel ULg; Linden, Annick ULg; Lekeux, Pierre ULg

in American Journal of Veterinary Research (1995), 56(5), 545-554

Owing to technical and ethical limitations, a substantial part of the knowledge about the pathophysiologic mechanism of the human diaphragm has been obtained from studies in which phrenic nerve activation ... [more ▼]

Owing to technical and ethical limitations, a substantial part of the knowledge about the pathophysiologic mechanism of the human diaphragm has been obtained from studies in which phrenic nerve activation was usually carried out by direct surgical exposure of the nerves in the neck of deeply anesthetized, mechanically ventilated animals. Novel information has been gleaned from such studies, but the restrictive conditions under which it was collected preclude reliable extrapolation. We, therefore, addressed the question of whether accurate electrophysiologic evaluation of the phrenic nerve-diaphragm pathway can be performed in intact, nonanesthetized calves. Transjugular phrenic activation was well tolerated, safe, specific, and able to achieve constant symmetric and supramaximal phrenic stimulations during prolonged periods. Eighteen noninvasive cutaneous and esophageal reception circuits were tested for their ability to record the diaphragmatic evoked potential. In addition, they were compared for specificity and reproducibility of the recorded potentials during prolonged periods of tidal or stimulated respiration. The best diaphragmatic potential was recorded from surface electrodes attached to the skin of the ninth and tenth intercostal spaces, using a xyphoidian reference. We describe a method that allows easy, longterm, and reliable electrophysiologic evaluation of the phrenic nerve-diaphragm pathway in intact, conscious calves. It is hoped that such a model will produce relevant novel information regarding pathophysiology of the diaphragm. [less ▲]

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See detailValidation of Creatine, Glycogen and L-(+)-Lactate Determination in Biopsy Samples of Bovine Musculus Diaphragma
Desmecht, Daniel ULg; Linden, Annick ULg; Cuvelier-Klimek, M. et al

in Journal of Veterinary Medicine. A, Physiology, Pathology, Clinical Medicine (1995), 42(1), 13-26

Whereas reliable measurements of diaphragmatic force and electrical activity are now available in calves, evidence that substrate contents in the bovine diaphragm can be accurately measured is still ... [more ▼]

Whereas reliable measurements of diaphragmatic force and electrical activity are now available in calves, evidence that substrate contents in the bovine diaphragm can be accurately measured is still lacking. The purposes of the present study were therefore a) to describe and test the reliability of methods and procedures used for sampling, lyophilisation, extraction and dosage of muscular lactate, glycogen and creatine contents and b) to report the variation in their levels found along the bovine diaphragm and among individuals. The repeatability of the results yielded by a) assaying the extracts, b) processing and assaying the extracts and c) taking samples at different sites in the muscle was assessed. Neither assay, nor processing effects were significant (P < or = 0.05). Substrates were found to be homogeneously distributed within the two muscles studied. Substrate contents expressed per unit of muscle weight or total creatine were neither more or less variable than when expressed per unit of dry matter. [less ▲]

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See detailEffect of adenosine IV administration on gas exchanges and hemodynamics in unsedated calves with hypoxic vasoconstruction
Van de Weerdt, Marie-Lys; Desmecht, Daniel ULg; Vandenput, Sandrina ULg et al

in Pflügers Archiv : European Journal of Physiology (1995), 430(5), 186

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See detailPhysiologie et physiopathologie du facteur d'activation plaquettaire et perspectives thérapeutiques de ses antagonistes
Van de Weerdt, ML; Desmecht, Daniel ULg; Lekeux, Pierre ULg

in Annales de Médecine Vétérinaire (1995), 139

Le facteur d'activation plaquettaire (PAF) est un phospholipide dérivé de l'acide arachidonique dont la particularité est d'activer l'agrégation et la dégranulation des plaquettes. Le PAF est également un ... [more ▼]

Le facteur d'activation plaquettaire (PAF) est un phospholipide dérivé de l'acide arachidonique dont la particularité est d'activer l'agrégation et la dégranulation des plaquettes. Le PAF est également un puissant médiateur de l'inflammation sécrété par de multiples cellules. Il est capable de moduler et d'amplifier la cascade de l'inflammation. Ce travail de synthèse expose dans sa première partie, le processus de biosynthèse du PAF ainsi que le rôle qu'il joue dans le rétrocontrôle ou l'amplification de la cascade de l'inflammation. Dans la seconde partie, l'accent est mis sur la physiopathologie du PAF et cela plus particulièrement pour les systèmes respiratoire et cardiovasculaire. Enfin, les antagonistes du PAF les plus couramment utilisés sont repris dans un tableau où figurent l'espèce étudiée ainsi que les améliorations cliniques obtenues. [less ▲]

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See detailInvolvement of 5-hydroxytryptamine in hyperdynamic pulmonary hemodynamics in endotoxemic calves
Desmecht, Daniel ULg; Linden, Annick ULg; Amory, Hélène ULg et al

in Pflügers Archiv : European Journal of Physiology (1995), 429

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See detailThree cases of Pemphigus Foliaceus in horses
Amory, Hélène ULg; Beco, L; Desmecht, Daniel ULg et al

in Proceedings of the XXVth Congress of the World Veterinary Association (1995)

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See detailHemodynamic effects of intratracheal administration of Pasteurella haemolytica in calves
Amory, Hélène ULg; Linden, Annick ULg; Desmecht, Daniel ULg et al

in Pflügers Archiv : European Journal of Physiology (1995), 430

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See detailComparative assessment of right ventricular performance from the pressure-volume relationship in double-muscled and conventional calves.
Amory, Hélène ULg; Mc Entee, Kathleen ULg; Linden, Annick ULg et al

in Canadian Journal of Veterinary Research = Revue Canadienne de Recherche Vétérinaire (1995), 59(2), 135-141

Forty-one and 55 records of right-sided and systemic arterial pressures, cardiac output, and end-diastolic and end-systolic right ventricular volumes were collected from a group of 6 conventional and 6 ... [more ▼]

Forty-one and 55 records of right-sided and systemic arterial pressures, cardiac output, and end-diastolic and end-systolic right ventricular volumes were collected from a group of 6 conventional and 6 double-muscled calves, respectively. In each group, the mean right ventricular pressure-volume loop was constructed. Global cardiac performance was significantly lower in the double-muscled than in the conventional calves. The right ventricular end-diastolic and end-systolic volumes, as well as the diastolic portion of the mean pressure-volume loop, were similar in the 2 groups. Those results suggest that the reduced cardiac performance of double-muscled calves is not due to a lowered ventricular preload and that diastolic properties of their myocardium are similar to those of conventional calves. When expressed on a body weight basis, however, the right ventricular end-diastolic and end-systolic volumes were lower in the double-muscled than in conventional calves. When expressed as a function of probable metabolic demand, therefore, the volumetric capacity of the cardiac pump appears to be reduced in double-muscled calves. The significantly lower right ventricular ejection fraction, maximal rate of ventricular pressure rise and right ventricular peak-systolic pressure to end-systolic volume ratio measured in double-muscled as compared with conventional calves suggest that reduced myocardial contractility may also be partly responsible for the significantly lower stroke index of the former calves. The cardiac pump of double-muscled cattle thus seems to be less effective than that of conventional cattle because of reduced volumetric capacity and lowered strength of contraction. [less ▲]

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See detailHemodynamic effects of intratracheal administration of Pasteurella haemolytica in calves
Amory, Hélène ULg; Linden, Annick ULg; Desmecht, Daniel ULg et al

in Pflügers Archiv : European Journal of Physiology (1995), 430

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See detailMaximal cardiac pumping capacity in double-muscled cattle as determined by a pharmacological test
Amory, Hélène ULg; Mc Entee, Kathleen ULg; Linden, Annick ULg et al

in Pflügers Archiv : European Journal of Physiology (1995), 430

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See detailPathophysiological response of bovine diaphragm function to gastric distension
Desmecht, Daniel ULg; Linden, Annick ULg; Lekeux, Pierre ULg

in Journal of Applied Physiology (1995), 78

Because of the anatomic association of an exceptionally bulky stomach with a striking compartmentation of the chest wall, leading to the most cranial insertion of the diaphragm among mammals, gastric ... [more ▼]

Because of the anatomic association of an exceptionally bulky stomach with a striking compartmentation of the chest wall, leading to the most cranial insertion of the diaphragm among mammals, gastric overdistension in the bovine species offers a unique pathophysiological condition for the diaphragm. The purpose of the present study was to determine whether increased intragastric pressure (Pga) (1, 2, 3, 4, and 5 kPa) leads to perturbations of respiratory and diaphragm function in calves. Changes in diaphragmatic strength and inspiratory action followed a biphasic pattern: 1) transdiaphragmatic pressure (Pdi) in response to constant bilateral maximal phrenic nerve stimulation at 30 Hz increased with moderate gastric distension and then fell abruptly as Pga continued to rise and 2) the magnitude of the ratio of the fall in pleural pressure to total Pdi was maintained up to a Pga amounting to 2 kPa but declined at higher pressures. We conclude that gastric distension in the bovine species provokes physiologically significant alterations of the diaphragm excitation-to-pressure generation coupling as well as of its capacity to convert Pdi into useful inspiratory pleural pressure. We suggest that these perturbations resulted from the combination of 1) altered tension-generating capacity due to compromised perfusion, 2) altered diaphragm geometry capable of altering tension-to-pressure generation coupling, and 3) modified coupling of the diaphragm with the chest wall that reduced its ability to drive inspiration [less ▲]

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See detailPathophysiological response of bovine pulmonary function to gastric distension
Desmecht, Daniel ULg; Linden, Annick ULg; Lekeux, Pierre ULg

in Journal of Comparative Pathology (1995), 112

The purpose was to determine whether gastric overdistension leads to lifethreatening perturbations of pulmonary gas exchange in healthy calves. Six animals were studied with normal (0 kPa) and increased ... [more ▼]

The purpose was to determine whether gastric overdistension leads to lifethreatening perturbations of pulmonary gas exchange in healthy calves. Six animals were studied with normal (0 kPa) and increased (1, 2, 3, 4 and 5 kPa) intragastric pressure (IGP). Changes in pleural pressures and peak expiratory flow paralleled those of IGP. Inspiratory pressure-time index remained stable throughout the insufflation process. Pulmonary function values were characterized by abrupt changes with increasing IGP. Tidal volume declined as IGP increased and, along with inspiratory flow, decreased abruptly with the highest pressure (5 kPa). Respiratory rate progressively increased up to an IGP of 4 kPa, then decreased by 30%, due to breath-holding at the end of inspiration. Minute volume increased with IGP up to 4 kPa, but dramatically declined at 5 kPa. Total pulmonary resistance remained stable throughout the insufflation process, whereas lung dynamic compliance fell abruptly to one-half of its baseline value at IGPs of 1 kPa and above. Arterial oxygen tension was maintained at an IGP of 1 kPa, slightly diminished at 2–3 kPa, and markedly decreased at 4–5 kPa. Hypercapnia and respiratory acidosis developed progressively with increasing IGP. Changes in arterial gases were probably due to a combination of (1) alveolar hypoventilation, caused by altered tidal to dead space volume ratio, inadequate central nervous system “drive”, altered effectiveness of inspiratory muscle action, or end-inspiratory breath-holding, and (2) ventilation to perfusion mismatch, caused by perfusion of collapsed lung units. In the range of IGPs used, standardized arterial pH did not decline below the control value, which suggests that perfusion of peripheral tissues remained sufficient, and that respiratory failure rather than cardiovascular failure may be the principal physiopathological effect of increased gastric pressure [less ▲]

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See detailAssessment of equine diaphragm strength and activation using transvenous phrenic nerve stimulation
Desmecht, Daniel ULg; Linden, Annick ULg; Lekeux, Pierre ULg

in Equine Veterinary Journal. Supplement (1995), 18

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