Pulmonary Response to Intravenous Administration of 5-Hydroxytryptamine after Type-2 Receptor Blockade in Healthy Calves
Linden, Annick ; Desmecht, Daniel ; Amory, Hélène et al
in American Journal of Veterinary Research (1993), 54(1), 168-73
The purpose of this study was to investigate the mechanism by which 5-hydroxytryptamine (5-HT) modifies respiratory function, specifically, hyperventilation, diffuse bronchoconstriction, and pulmonary ... [more ▼]
The purpose of this study was to investigate the mechanism by which 5-hydroxytryptamine (5-HT) modifies respiratory function, specifically, hyperventilation, diffuse bronchoconstriction, and pulmonary arterial hypertension in cattle. We determined whether the IV response to 5-HT in calves was attributable to stimulation of 5-HT2 receptors. Six healthy unsedated young bull calves of the Friesian (n = 4) and of the Belgian White and Blue (n = 2) breeds were used. A specific 5-HT2 antagonist (metrenperone, 0.05 mg/kg of body weight) was administered IM 30 minutes before the cattle were given a 5-minute IV 5-HT infusion. Pulmonary function values were registered before, during, and after the 5-HT challenge infusion. Minute volume increased significantly, because of an increase in respiratory rate. Conversely, lung dynamic compliance, total pulmonary resistance, and pulmonary arterial pressure were not changed. We concluded that in cattle, 5-HT-induced ventilatory response is not mediated through activation of 5-HT2 receptors. However, the 5-HT2 receptors are involved in 5-HT-induced broncho- and pulmonary vasoconstriction. [less ▲]Detailed reference viewed: 12 (1 ULg)
Pulmonary surfactant from healthy Belgian white and blue and Holstein Friesian calves: Biochemical and biophysical comparison
; ; et al
in Veterinary Journal (2002), 163
The biochemical composition and biophysical behaviour of pulmonary surfactant samples isolated from healthy Belgian White and Blue (BWB) and Holstein Friesian (HF) calves have been investigated and ... [more ▼]
The biochemical composition and biophysical behaviour of pulmonary surfactant samples isolated from healthy Belgian White and Blue (BWB) and Holstein Friesian (HF) calves have been investigated and compared. Interesting differences in composition have been demonstrated. In particular, a higher level of total hydrophobic surfactant-associated proteins (SP) (due to higher levels of SP-B and SP-C) is reported in HF calves compared to BWB calves. Higher levels of phosphatidylcholine (PC) and especially the disaturated form of PC were also found in HF as compared to BWB calves. No immediate effect on the surface tension properties evaluated by the pulsating bubble surfactometer was found between the surfactant samples of the two breeds under physiological conditions. However, since a high content of disaturated PC and the presence of the SP-B and SP-C are thought to be essential for the surface activity, we propose that the reported modifications could contribute to the apparently lower resistance of the BWB calves to respiratory troubles in comparison with HF calves. (C) 2002 Elsevier Science Ltd. All rights reserved. [less ▲]Detailed reference viewed: 15 (2 ULg)
Pulmonary vascular response of healthy calves to intravenous and aerosol 5-hydroxytryptamine
Desmecht, Daniel ; Amory, Hélène ; Rollin, Frédéric et al
in Archives Internationales de Physiologie et de Biochimie (1990)Detailed reference viewed: 2 (0 ULg)
Pulmonary vein to pulmonary artery ratio is an echocardiographic index of left congestive heart failure in dogs with myxomatous mitral valve disease
Merveille, Anne-Christine ; ; Krafft, Emilie et al
in Proceedings of the 23th ECVIM Meeting (2013, September)Detailed reference viewed: 27 (6 ULg)
Pulmonary veno-occlusive disease in myeloproliferative disorder.
Willems, Evelyne ; Canivet, Jean-Luc ; Ghaye, Benoît et al
in European Respiratory Journal (2009), 33(1), 213-216
The present study reports a case of biopsy-proven pulmonary veno-occlusive disease as a cause of severe pulmonary hypertension in a patient suffering from a chronic myeloproliferative disorder. The ... [more ▼]
The present study reports a case of biopsy-proven pulmonary veno-occlusive disease as a cause of severe pulmonary hypertension in a patient suffering from a chronic myeloproliferative disorder. The pulmonary disease evolved favourably under treatment with defibrotide, a pro-fibrinolytic medication used in hepatic veno-occlusive disease. [less ▲]Detailed reference viewed: 67 (22 ULg)
Pulmonary Ventilation, Mechanics, Gas Exchange and Haemodynamics in Calves Following Intratracheal Inoculation of Pasteurella Haemolytica
Linden, Annick ; Desmecht, Daniel ; Amory, Hélène et al
in Zentralblatt für Veterinarmedizin. Reihe A (1995), 42(8), 531-544
A Pasteurella haemolytica A1 broth was injected intratracheally in eight calves and measurements of pulmonary function values (PFV) were made once before and hourly post inoculation (p.i.). Changes in ... [more ▼]
A Pasteurella haemolytica A1 broth was injected intratracheally in eight calves and measurements of pulmonary function values (PFV) were made once before and hourly post inoculation (p.i.). Changes in PFVs, included increased respiratory rate and minute ventilation (up to 158% of baseline 2 h p.i.) and decreased tidal volume and lung dynamic compliance (up to 33% of baseline 3 h p.i.). Total pulmonary resistance was not affected. At and after 3 h p.i. there was a progressive impairement of gas exchange, as judged from arterial O2 tension which decreased up to 65% of baseline. In contrast, arterial CO2 tension was not affected. Pulmonary hypertension was observed during the 3 last h of the study and was attributable to an increased pulmonary vascular resistance. Severe neutropenia was observed at 3 h p.i. and post-mortem histological findings were consistent with an acute fibrinohemorragic bronchopneumonia. In conclusion, P. haemolytica airway challenge unequiovocally resulted in acute pneumonia, providing a reproducible pathophysiological model for investigations regarding new therapeutic strategies. [less ▲]Detailed reference viewed: 59 (3 ULg)
Pulp temperature increase during photo-activated disinfection (PAD) of periodontal pockets: an in vitro study.
; ; et al
in Lasers in medical science (2010)
The capacity of photo-sensitizers, used in combination with laser light to kill micro-organisms has been demonstrated in different studies. Photo-activated disinfection (PAD) has been introduced in ... [more ▼]
The capacity of photo-sensitizers, used in combination with laser light to kill micro-organisms has been demonstrated in different studies. Photo-activated disinfection (PAD) has been introduced in periodontology as an aid for disinfection of periodontal pockets. The aim of this study is to verify the harm for dental vitality of the use of PAD in periodontal pockets. Root canals of 24 freshly extracted human teeth where prepared using profiles up to a size of ISO #50 and filled with thermo-conductor paste. A silicon-based false gum was made in which a periodontal pocket was created and filled with photo-sensitizer phenothiazine chloride (phenothiazine-5-ium, 3.7-bis (dimethylamino)-, chloride). The external root surface was irradiated during 60 s with a 660-nm diode laser (output power: 20 mW; power density: 0.090 W/cm(2); Energy density: 5.46 J/cm(2)) using a periodontal tip with a diameter of 1 mm and a length of 7 mm. Temperatures were recorded inside the root canal using a thermocouple. Measurements were recorded every second, starting at 10 s before lasering, during the irradiation and were continued for 150 s after the end of irradiation, and six measurements were done per tooth. An average temperature increase of 0.48 +/- 0.11 degrees C was recorded. Our results demonstrated that pulp temperature increase was lower than 3 degrees C, which is considered to be harmless for pulp injury. Regarding pulp temperature increase, the use of PAD for disinfection of periodontal pockets can be considered as a safe procedure for dental vitality. [less ▲]Detailed reference viewed: 54 (6 ULg)
Pulpes de betteraves surpressées complémentées ou aliments complets secs pour les taurillons en croissance-finition.
Thewis, André ; ; et al
in Elevages Belges (1985), 39(7), 13-16Detailed reference viewed: 29 (1 ULg)
Les pulpes de betteraves surpressées complémentées: composition chimique, valeur alimentaire et utilisation par les taurillons en croissance-finition.
in Courrier de la Betterave (1985), (2), 10-12Detailed reference viewed: 58 (6 ULg)
Pulsatile glucagon has greater hyperglycaemic, lipolytic and ketogenic effects than continuous hormone delivery in man: effect of age.
; ; et al
in Diabetologia (1990), 33(5), 272-7
The present study aimed at investigating the hyperglycaemic, lipolytic and ketogenic effects of small doses of glucagon delivered continuously or in a pulsatile manner. The study was performed in eight ... [more ▼]
The present study aimed at investigating the hyperglycaemic, lipolytic and ketogenic effects of small doses of glucagon delivered continuously or in a pulsatile manner. The study was performed in eight healthy young volunteers (24.2 +/- 1.2 years) and in eight healthy aged subjects (69.4 +/- 2.0 years). In all the subjects, endogenous pancreatic hormone secretion was inhibited by somatostatin and only glucagon was replaced. Consequently, the effects of pulsatile and continuous glucagon delivery were studied in conditions of progressive somatostatin-induced insulin deficiency. In both the young and the aged subjects, pulsatile glucagon delivery resulted in increases in plasma glucose, non-esterified fatty acid, glycerol and beta-hydroxybutyrate levels greater than those observed when the same amount of glucagon was delivered in a continuous manner. The net increases in plasma glucose, glycerol and non-esterified fatty acid levels were similar between the young and the aged subjects when glucagon was infused continuously; in contrast, the rise in plasma beta-hydroxybutyrate in the aged was only about half that observed in the young subjects. Surprisingly, when glucagon was infused in a pulsatile manner, the rises in plasma glycerol, non-esterified fatty acid and beta-hydroxybutyrate levels were all significantly smaller in the aged subjects, while no significant differences were observed in the blood glucose responses. We conclude that, in the presence of somatostatin-induced insulin deficiency, pulsatile glucagon exerts greater effects on blood glucose, plasma non-esterified fatty acid, glycerol and beta-hydroxybutyrate levels than its continuous delivery. In the elderly, the lipolytic and ketogenic, but not the hyperglycaemic, responses to pulsatile glucagon are significantly reduced. [less ▲]Detailed reference viewed: 14 (0 ULg)
Pulsatile hyperglucagonemia fails to increase hepatic glucose production in normal man.
; Scheen, André ; et al
in American Journal of Physiology (1987), 252(1 Pt 1), 1-7
To study the metabolic effects of pulsatile glucagon administration, six male volunteers were submitted to a 260-min glucose-controlled glucose intravenous infusion using the Biostator. The endogenous ... [more ▼]
To study the metabolic effects of pulsatile glucagon administration, six male volunteers were submitted to a 260-min glucose-controlled glucose intravenous infusion using the Biostator. The endogenous secretion of the pancreatic hormones was inhibited by somatostatin (100 micrograms X h-1), basal insulin secretion was replaced by a continuous insulin infusion (0.2 mU X kg-1 X min-1), and glucagon was infused intravenously in two conditions at random: either continuously (125 ng X min-1) or intermittently (812.5 ng X min-1, with a switching on/off length of 2/11 min). Blood glucose levels and glucose infusion rate were monitored continuously by the Biostator, and classical methodology using a D-[3-3H]glucose infusion allowed us to study glucose turnover. While basal plasma glucagon levels were similar in both conditions (122 +/- 31 vs. 115 +/- 18 pg X ml-1), they plateaued at 189 +/- 38 pg X ml-1 during continuous infusion and varied between 95 and 501 pg X ml-1 during pulsatile infusion. When compared with continuous administration, pulsatile glucagon infusion initially induced a similar increase in endogenous (hepatic) glucose production and blood glucose, did not prevent the so-called "evanescent" effect of glucagon on blood glucose, and after 3 h tended to reduce rather than increase hepatic glucose production. In conclusion, in vivo pulsatile hyperglucagonemia in normal man fails to increase hepatic glucose production. [less ▲]Detailed reference viewed: 13 (0 ULg)
Pulsatile insulin delivery has greater metabolic effects than continuous hormone administration in man: importance of pulse frequency.
; Scheen, André ; et al
in Journal of Clinical Endocrinology and Metabolism (1991), 72(3), 607-15
The aim of this study was to see if the greater effect of insulin on hepatic glucose output when insulin is given using 13-min pulses in man remains when the same amount of insulin is delivered using 26 ... [more ▼]
The aim of this study was to see if the greater effect of insulin on hepatic glucose output when insulin is given using 13-min pulses in man remains when the same amount of insulin is delivered using 26-min pulses. The study was performed on nine male healthy volunteers submitted to a 325 min glucose-controlled glucose iv infusion using the Biostator. The endogenous secretion of pancreatic hormones was inhibited by somatostatin. Three experiments were performed in each subject on different days and in random order. In all cases glucagon was replaced (58 ng min-1). The amounts of insulin infused were identical in all instances and were 0.2 mU kg-1 min-1 (continuous), 1.3 mU kg-1 min-1, 2 min on and 11 min off (13-min pulses) or 2.6 mU kg-1 min-1, 2 min on and 24 min off (26-min pulses). Blood glucose levels and glucose infusion rate were monitored continuously by the Biostator, and classic methodology using D-[3-3H] glucose infusion allowed to study glucose turnover. When compared with continuous insulin, 13-min insulin pulses induced a significantly greater inhibition of endogenous glucose production. This effect disappeared when insulin was delivered in 26-min pulses. We conclude that, in man, an adequate pulse frequency is required to allow the appearance of the greater inhibition of pulsatile insulin on endogenous glucose production. [less ▲]Detailed reference viewed: 12 (0 ULg)
Pulsatile insulin delivery is more efficient than continuous infusion in modulating islet cell function in normal subjects and patients with type 1 diabetes.
; ; et al
in Journal of Clinical Endocrinology and Metabolism (1988), 66(6), 1220-6
The respective modulating effects of continuous and intermittent insulin delivery on pancreatic islet cell function were studied in seven normal men and nine insulin-dependent (type 1) diabetic patients ... [more ▼]
The respective modulating effects of continuous and intermittent insulin delivery on pancreatic islet cell function were studied in seven normal men and nine insulin-dependent (type 1) diabetic patients. In the normal men, saline or continuous (0.8 mU kg-1 min-1) or pulsatile (5.2 mU kg-1 min-1, with a switching on/off length of 2/11 min) human insulin were delivered on different days and in random order. Despite hyperinsulinemia, blood glucose was kept close to its basal value by the glucose clamp technique. The diabetic patients also were infused in random order and on different days with either saline or a smaller amount of insulin delivered continuously (0.15 mU kg-1 min-1) or in a pulsatile manner (0.97 mU kg-1 min-1 for 2 min, followed by 11 min during which no insulin was infused). In all experiments, 5 g arginine were given iv as a bolus dose 30 min before the end of the study, and plasma C-peptide and glucagon levels were determined to assess islet cell function. In the normal men, insulin administration resulted in a significant decline of basal plasma glucagon and C-peptide levels and in a clear-cut decrease in the arginine-induced glucagon response. These effects of insulin were significantly more marked when insulin was delivered in a pulsatile rather than a continuous manner. In the insulin-dependent diabetic patients, the lower dose of insulin infused continuously did not alter the basal or arginine-stimulated glucagon response. In contrast, when the same amount of insulin was delivered intermittently, arginine-induced glucagon release was greatly reduced. Thus, these data support the concept that insulin per se is a potent physiological modulator of islet A- and B-cell function. Furthermore, they suggest that these effects of insulin are reinforced when the hormone is administered in an intermittent manner in an attempt to reproduce the pulsatile physiological release of insulin. [less ▲]Detailed reference viewed: 8 (1 ULg)
Pulsatile stress in middle-aged patients with Type 1 or Type 2 diabetes compared to nondiabetic controls.
Philips, Jean-Christophe ; Marchand, Monique ; Scheen, André
in Diabetes Care (2010), 33(11), 2424-2429
AbstractBackground: Arterial pulse pressure (PP) is considered as an independent cardiovascular risk factor. We compared PP during an active orthostatic test in middle-aged patients with type 1 diabetes ... [more ▼]
AbstractBackground: Arterial pulse pressure (PP) is considered as an independent cardiovascular risk factor. We compared PP during an active orthostatic test in middle-aged patients with type 1 diabetes and with type 2 diabetes, and corresponding nondiabetic controls. Methods: 40 patients with type 1 diabetes (mean age 50 years, diabetes duration 23 years, BMI 23.0 kg/m(2)) were compared to 40 non hypertensive patients with type 2 diabetes (respectively, 50 years, 8 years, 29.7 kg/m(2)). Patients taking antihypertensive agents or with renal insufficiency were excluded. All patients were evaluated with a continuous noninvasive arterial blood pressure monitoring (Finapres(R)) in standing (1 min), squatting (1 min) and again standing position (1 min). Patients with type 1 or type 2 diabetes were compared with two groups of 40 age-, sex- and BMI-matched healthy subjects. Results: Patients with type 1 diabetes and patients with type 2 diabetes showed significantly higher PP, heart rate (HR) and PPxHR double product (type 1 : 5263 vs 4121 mmHg/min, p=0.0004; type 2 : 5359 vs 4321 mmHg, p=0.0023) levels than corresponding controls. There were no significant differences between patients with type 1 diabetes and type 2 diabetes regarding PP (59 vs 58 mmHg), HR (89 vs 88/min), and PPxHR product (5263 vs 5359 mmHg/min). Conclusion: Patients with type 1 diabetes have comparable increased levels of peripheral PP, an indirect marker of arterial stiffness, and PPxHR, an index of pulsatile stress, as non-hypertensive patients with type 2 diabetes at similar mean age of 50 years. [less ▲]Detailed reference viewed: 32 (1 ULg)
A pulsating auroral X-ray hot spot on Jupiter
; ; Grodent, Denis et al
in Nature (2002), 415(6875), 1000-1003
Jupiter's X-ray aurora has been thought to be excited by energetic sulphur and oxygen ions precipitating from the inner magnetosphere into the planet's polar regions(1-3). Here we report high-spatial ... [more ▼]
Jupiter's X-ray aurora has been thought to be excited by energetic sulphur and oxygen ions precipitating from the inner magnetosphere into the planet's polar regions(1-3). Here we report high-spatial-resolution observations that demonstrate that most of Jupiter's northern auroral X-rays come from a 'hot spot' located significantly poleward of the latitudes connected to the inner magnetosphere. The hot spot seems to be fixed in magnetic latitude and longitude and occurs in a region where anomalous infrared(4-7) and ultraviolet(8) emissions have also been observed. We infer from the data that the particles that excite the aurora originate in the outer magnetosphere. The hot spot X-rays pulsate with an approximately 45-min period, a period similar to that reported for high-latitude radio and energetic electron bursts observed by near-Jupiter spacecraft(9,10). These results invalidate the idea that jovian auroral X-ray emissions are mainly excited by steady precipitation of energetic heavy ions from the inner magnetosphere. Instead, the X-rays seem to result from currently unexplained processes in the outer magnetosphere that produce highly localized and highly variable emissions over an extremely wide range of wavelengths. [less ▲]Detailed reference viewed: 31 (11 ULg)
Pulsating B-type Stars in the Open Cluster NGC 884: Frequencies, Mode Identification, and Asteroseismology
; Briquet, Maryline ; et al
in Astronomical Journal (2013), 146
Recent progress in the seismic interpretation of field β Cep stars has resulted in improvements of the physical description in the stellar structure and evolution model computations of massive stars ... [more ▼]
Recent progress in the seismic interpretation of field β Cep stars has resulted in improvements of the physical description in the stellar structure and evolution model computations of massive stars. Further asteroseismic constraints can be obtained from studying ensembles of stars in a young open cluster, which all have similar age, distance, and chemical composition. We present an observational asteroseismology study based on the discovery of numerous multi-periodic and mono-periodic B stars in the open cluster NGC 884. We describe a thorough investigation of the pulsational properties of all B-type stars in the cluster. Overall, our detailed frequency analysis resulted in 115 detected frequencies in 65 stars. We found 36 mono-periodic, 16 bi-periodic, 10 tri-periodic, and 2 quadru-periodic stars and one star with nine independent frequencies. We also derived the amplitudes and phases of all detected frequencies in the U, B, V, and I filter, if available. We achieved unambiguous identifications of the mode degree for 12 of the detected frequencies in nine of the pulsators. Imposing the identified degrees and measured frequencies of the radial, dipole, and quadrupole modes of five pulsators led to a seismic cluster age estimate of log (age/yr) = 7.12-7.28 from a comparison with stellar models. Our study is a proof-of-concept for and illustrates the current status of ensemble asteroseismology of a young open cluster. [less ▲]Detailed reference viewed: 7 (1 ULg)
La pulsation du cœur du chien est une onde de contraction qui débute dans l’oreillette droite, s’étend rapidement aux parois des deux oreillettes, puis franchit lentement le faisceau de His pour s’irradier rapidement dans la substance des ventricules
in Archives Internationales de Physiologie (1906), IVDetailed reference viewed: 3 (0 ULg)