References of "Linden, Annick"
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See detailLes mycoplasmes respiratoires des bovins : I. Clinique, diagnostic et traitement
Linden, Annick ULg; Thomas, A.; Mainil, Jacques ULg

in Annales de Médecine Vétérinaire (1998), 142

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See detailLes mycoplasmes respiratoires des bovins : II. Propriétés de virulence et vaccination
Mainil, Jacques ULg; Thomas, A.; Linden, Annick ULg

in Annales de Médecine Vétérinaire (1998), 142

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See detailPulmonary Function Values in Friesian and Double-Muscled Calves During Acute Poikilocapnic Hypoxia
Rollin, Frédéric ULg; Amory, Hélène ULg; Desmecht, Daniel ULg et al

in Zentralblatt für Veterinarmedizin. Reihe A (1997), 44(2), 79-90

The effects of an acute non-isocapnic hypoxia on ventilation and pulmonary mechanics were investigated in 6 healthy unsedated Holstein-Friesian (HF) calves and in 7 double-muscled calves of the Belgian ... [more ▼]

The effects of an acute non-isocapnic hypoxia on ventilation and pulmonary mechanics were investigated in 6 healthy unsedated Holstein-Friesian (HF) calves and in 7 double-muscled calves of the Belgian White and Blue (BWB) breed known to develop more severe hypoxemia during exercise and respiratory diseases. Data were collected at 1 min intervals throughout the following protocol: breathing air (FIO2 = 21%), then breathing hypoxic gas mixture (FIO2 = 10%) for 5 min, and, finally, breathing air again for 5 min of recovery. Arterial blood was sampled at rest and at the 4th min of hypoxia for blood gas analysis. In HF and BWB calves, hypoxia induced a significant increase in tidal and minute volume, but did not change respiratory rate, dynamic lung compliance and total pulmonary resistance. However, with regard to their ventilation during normoxia at rest, BWB calves showed a comparatively greater rise in ventilation than HF calves during the first 4 min of hypoxia. On the contrary, by the 5th minute of hypoxia, ventilation of BWB calves declined to the normoxic level while HF calves largely sustained hyperventilation. This hypoxic ventilatory depression in BWB calves could be explained by the proportionately greater initial increase in ventilation. It was concluded that BWB calves supported this hypoxic challenge less easily than HF calves. [less ▲]

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See detailVentilatory Effects of the Single-Breath Co2 Test, Compared with Eructation, in Cattle
Rollin, Frédéric ULg; Desmecht, Daniel ULg; Genicot, B. et al

in American Journal of Veterinary Research (1997), 58(3), 310-6

OBJECTIVE: To assess the peripheral chemoreceptor-induced ventilatory response to single tidal-breath CO2 (SB CO2) tests, compared with eructations, in 2 breeds of calves. ANIMALS: 13 conscious unsedated ... [more ▼]

OBJECTIVE: To assess the peripheral chemoreceptor-induced ventilatory response to single tidal-breath CO2 (SB CO2) tests, compared with eructations, in 2 breeds of calves. ANIMALS: 13 conscious unsedated Holstein-Friesian and 8 Belgian White and Blue hypermuscled calves. PROCEDURE: An SB of +/- 50% CO2 in equal parts of O2 and N2 was inhaled. Ventilatory response was determined from the increase in ventilation (delta Ve) during the first 20 seconds after the test breath or eructation and from the difference in end-tidal PCO2 between the stimulus and preceding control breaths. RESULTS: Because no difference was found between the 2 breeds of calves, all data were pooled. The increase in Ve peaked during the fifth breath after the SB CO2 test on average, corresponding to a delay of 12.4 seconds. The SB CO2 responses ranged from 0.037 to 0.151 L/min.mm of Hg.m2, with a mean +/- SD of 0.082 +/- 0.032 L/min.mm of Hg.m2 for all calves. The SB CO2 tests, similar to eructations, modified the breathing pattern significantly and in the same direction, by principally shortening expiratory time and increasing mean inspiratory flow. After eructations, Ve peak increase was more important for lower difference in end-tidal PCO2 between the stimulus and preceding control breaths and took place more rapidly than after SB CO2 tests. Accordingly, eructation responses were more marked than SB CO2 responses and averaged 0.925 +/- 0.276 L/min.mm of Hg.m2. CONCLUSIONS AND CLINICAL RELEVANCE: In cattle, the pattern of breathing and ventilation under basal conditions is characterized by a cyclic variability coupled to eructation. [less ▲]

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See detailEffects of Growth and Breed on Direct Static Measurements of Chest Wall Compliance in Cattle
Desmecht, Daniel ULg; Rollin, Frédéric ULg; Linden, Annick ULg et al

in Research in Veterinary Science (1997), 62(1, Jan-Feb), 1-5

Chest wall compliance (CW) was measured in 59 conscious standing calves, aged six to 162 days, which were breathing air spontaneously through a face mask. The airways were occluded at the end of ... [more ▼]

Chest wall compliance (CW) was measured in 59 conscious standing calves, aged six to 162 days, which were breathing air spontaneously through a face mask. The airways were occluded at the end of inspiration in order to elicit the Hering-Breuer reflex, the effectiveness of which was ensured by the presence of a plateau on the tracings of airway opening and oesophageal pressure (Pes). CW was measured directly from the inspired volume of the occluded breath and changes in Pes generated by the recoil of the relaxed chest wall. This airway-occlusion technique yielded reproducible CW values similar to those measured by classical invasive methods. The ratio of CW to bodyweight in the growing calves (sCW) ranged from 2.2 to 11.5 ml cmH2O-1 kg-1 and was correlated negatively with age: (log sCW = 0.91-0.003 x age, r = 0.68), the rate of decline corresponding well to the multispecies allometric growth relationship. [less ▲]

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See detailParasympathetic component of 5-hydroxytryptamine-induced pulmonary dysfunctions in health calves
Linden, Annick ULg; Desmecht, Daniel ULg; Amory, Hélène ULg et al

in American Journal of Veterinary Research (1996), 57(6), 896-901

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See detailCardiovascular response to exogenous serotonin in healthy calves
Linden, Annick ULg; Desmecht, Daniel ULg; Amory, Hélène ULg et al

in American Journal of Veterinary Research (1996), 57(5), 731-738

OBJECTIVE: To characterize the cardiovascular response to i.v. administration of serotonin (5-hydroxytryptamine [5-HT]) in calves. ANIMALS: 5 healthy unsedated Friesian calves. PROCEDURE: 41 5-HT ... [more ▼]

OBJECTIVE: To characterize the cardiovascular response to i.v. administration of serotonin (5-hydroxytryptamine [5-HT]) in calves. ANIMALS: 5 healthy unsedated Friesian calves. PROCEDURE: 41 5-HT administrations were performed: II slow infusions (duration, 5 minutes) and 30 bolus infusions (duration, 5 seconds). Cardiovascular function values were recorded before, during, and after the infusion. RESULTS: Slow infusion of 5HT first resulted in a brief period of severe bradycardia, then in sustained tachycardia with a concomitant increase in cardiac output. Systemic initial hypotension concomitant with bradycardia, then a pressor phase associated with an increase in systemic vascular resistance, and finally, a long-lasting hypotensive phase associated with decreased systemic vascular resistance. Pulmonary hypertension was associated with increased pulmonary vascular resistance, reflecting intense pulmonary vasoconstriction. Bolus infusion at increasing dosages resulted in dose-dependent bradycardia and systemic hypotension, followed by dose-dependent systemic hypertension. Unlike with slow infusion, neither the second tachycardiac nor the third systemic hypotensive phases were evident. CONCLUSIONS: 5-HT induces dose-dependent cardiovascular responses, including a reflex response followed by pulmonary and systemic vasoconstriction, in healthy calves. CLINICAL RELEVANCE: Determining the type of serotonergic receptors responsible for these responses may help to determine whether 5-HT is involved in the mechanisms underlying brisket disease in cattle. [less ▲]

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See detailHemodynamic Responses to Pasteurella Haemolytica Inoculation in Calves Given Type 2 Serotonergic Antagonist
Desmecht, Daniel ULg; Linden, Annick ULg; Amory, Hélène ULg et al

in Canadian Journal of Physiology & Pharmacology (1996), 74(5), 572-9

The effects of saline (control, group C) and metrenperone (treated, group M) on systemic and pulmonary hemodynamics were determined in conscious 7- to 15-day-old calves after they were intratracheally ... [more ▼]

The effects of saline (control, group C) and metrenperone (treated, group M) on systemic and pulmonary hemodynamics were determined in conscious 7- to 15-day-old calves after they were intratracheally inoculated with Pasteurella haemolytica. Metrenperone, a specific serotonin (5-hydroxytryptamine) receptor antagonist, was injected intramuscularly (100 micrograms.kg-1) 2 h after the calves were inoculated. Central venous, pulmonary arterial and capillary wedge, and systemic arterial pressures were measured, using fluid-filled catheters. Cardiac output was measured by the thermodilution technique. Heart rate, stroke volume, and pulmonary and systemic vascular resistances were calculated. The parameters were measured hourly from the 1st to the 10th h after inoculation. In group C, cardiovascular response to P. haemolytica inoculation was marked and typically consisted of two systemic hypotensive phases and two pulmonary hypertensive phases. The first phase occurred by the 2nd h post inoculation and was induced by a transient bradycardia and a systemic vasodilation, leading to profound hypotension and reduced venous return. Cardiac performance then transiently recovered, but systemic hypotension persisted. The second hypotensive hypodynamic phase occurred by the 7th h after inoculation, and was associated with a decline in stroke volume, an increase in heart rate, and pulmonary hypertension and vasoconstriction. In group M, the early response to P. haemolytica exposure was similar to that in controls, indicating that, as in sheep, 5-hydroxytryptamine does not contribute to the early hypodynamic response to endotoxemia. In contrast, metrenperone completely abolished late increases in pulmonary arterial pressure and pulmonary vascular resistance, suggesting that 5-hydroxytryptamine contributes to the late pulmonary vasoconstriction. Metrenperone treatment also allowed better restoration of heart rate, and hence, cardiac output was maintained. In conclusion, 5-hydroxytryptamine might have a role in mediating pasteurellic endotoxin induced changes in pulmonary hemodynamics through its type-2 receptors. [less ▲]

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See detailEffect of serotonergic blockade on calf pulmonary function after the intravenous administration of 3-methylindole
Linden, Annick ULg; Desmecht, Daniel ULg; Vandenput, Sandrina ULg et al

in Journal of Comparative Pathology (1996), 114(4), 361-371

This study was designed to investigate whether 3-methylindole (3-Mi), a tryptamine analogue, could cause pulmonary injury in calves other than by cytotoxicity. Injection of 3-Mi resulted in a marked ... [more ▼]

This study was designed to investigate whether 3-methylindole (3-Mi), a tryptamine analogue, could cause pulmonary injury in calves other than by cytotoxicity. Injection of 3-Mi resulted in a marked increase of respiratory rate, decrease of tidal volume and increase in minute ventilation. Pulmonary mechanics values were also profoundly affected, lung dynamic compliance being reduced to approximately one-third of its baseline value and total pulmonary resistance being increased two-fold. Arterial oxygen partial pressure was dramatically reduced. Successive challenges with 3-Mi after physiological saline pretreatment resulted in quantitatively identical alterations of pulmonary function values. Conversely, all these ventilatory, mechanical and gas exchange changes were abolished by pretreatment with serotonergic antagonists. It was concluded that intravenous administration of 3-Mi to healthy calves induced immediate and reversible bronchoconstriction which affected both central and peripheral airways. Because the effect was abolished by pretreatment with antiserotonin drugs, it is suggested that 3-Mi acts either directly by stimulating serotonergic receptors or indirectly through the release of serotonin from platelets. Current concepts of the physiopathological cascade underlying the toxicity of 3-Mi should, therefore, be re-evaluated in the light of this pharmacological mechanism. [less ▲]

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See detailRelationship of Plasma Lactate Production to Cortisol Release Following Completion of Different Types of Sporting Events in Horses
Desmecht, Daniel ULg; Linden, Annick ULg; Amory, Hélène ULg et al

in Veterinary Research Communications (1996), 20(4), 371-379

Fifty-eight healthy horses were studied during five sporting events of various intensities and durations, namely show-jumping (n = 6), cross-country in a three-day event (n = 30), trotting races (n = 7 ... [more ▼]

Fifty-eight healthy horses were studied during five sporting events of various intensities and durations, namely show-jumping (n = 6), cross-country in a three-day event (n = 30), trotting races (n = 7), galloping races (n = 7) and endurance rides (n = 8). Venous blood samples were collected at rest and immediately after exercise and analysed for plasma cortisol (CORT) and lactate (LA) levels. The experimental procedure was the same throughout the investigation so as to permit a reliable comparison between the five types of exercise. The type of event significantly affected both the resting (p < or = 0.05) and the post-exercise (p < or = 0.01) plasma CORT. The degree of exercise-induced hypercortisolaemia was related to both the intensity and the duration of exercise for all five sporting events, but the endurance ride induced the most and show-jumping the least serious post-exercise CORT changes. LA production was much more closely related to the intensity of the exercise than was CORT. It is concluded that simultaneous measurements of plasma CORT and LA levels may be useful to discriminate between different types of exercise, adjust training programmes, and improve our comprehension of the physiology of sport horses at exercise. [less ▲]

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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 detailDe l'effet du transport sur la cortisolémie du cheval de sport (première thèse annexe)
Linden, Annick ULg

Thèse d’agrégation de l’enseignement supérieur (1996)

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See detailMécanismes moléculaires et cellulaires de la pathogénie bactérienne (leçon publique)
Linden, Annick ULg

Thèse d’agrégation de l’enseignement supérieur (1996)

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See detailEffet de la compétition sur la formule leucocytaire et la cortisolémie du cheval de concours complet (troisième thèse annexe)
Linden, Annick ULg

Thèse d’agrégation de l’enseignement supérieur (1996)

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