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F Dagenais

Publications and source records attributed to F Dagenais.

At least 37 records · Page 2Linked to original sources
PubMed1996

Acute ascites with blunt cardiac rupture.

A unique case of acute ascites following blunt cardiac rupture is reported. A 32-year-old woman was admitted to another hospital and transferred to the authors' institution in cardiopulmonary shock with a very distended abdomen 2.5 h after a motor vehicle accident. Laparotomy was immediately performed and revealed 4 to 5 L of crystal clear fluid and a severe liver congestion. Cardiac tamponade was suspected and confirmed through a transdiaphragmatic pericardial window. Sternotomy was performed and a single right atrial appendage laceration identified, which was successfully repaired. The literature regarding blunt traumatic cardiac rupture is briefly reviewed, and the possible pathophysiology of ascites in a blunt traumatic cardiac rupture is discussed.

Accidents, Traffic↗
PubMed1996

Importance of outside hospital mortality as a first acute ischemic heart event: the Quebec Cardiovascular Study.

Among 4371 men aged 35 to 64 in 1973 who were randomly selected, living in Quebec City suburbs, without clinical evidence of ischemic heart disease (IHD) at entry and followed for 16 years, 426 had a first acute IHD event; of these, 296 had a nonfatal myocardial infarction (MI), 50 a fatal MI (death within four weeks of the acute event) and 80 an early death, ie, they died before the diagnosis of MI was made. Among these 80 early deaths attributed to IHD in the absence of any other apparent cause, 55 men died within 1 h from the onset of symptoms or were found dead in their bed (group A) while 25 died more than 1 h after the onset of symptoms (group B). In this population, a first acute IHD event carried a 31% (130 of 426) case fatality within the first four weeks. Groups A and B accounted for 42% (55 of 130) and 19% (25 of 130) of the total acute ischemic mortality, respectively. As expected, fatal events increased with age, but the proportion of early deaths over the total IHD mortality was as frequent in younger men as in older men. Smoking, increased systolic and diastolic blood pressure and serum cholesterol were associated with increased nonfatal events. A similar association, except for serum cholesterol, was observed for all fatal events. No significant risk factor profile differentiated early from late fatal events. In conclusion, in this population, nearly a third of men with a first IHD event died, most of them outside the hospital. None of the main established risk factors differentiated men with a fatal MI from those with an early death.

Adult↗
PubMed1995

Bronchogenic cyst of the right hemidiaphragm.

A rare case of bronchogenic cyst of the right hemidiaphragm is reported. The literature is reviewed briefly. Clinical presentation, diagnosis, and treatment of this entity are discussed further.

Bronchogenic Cyst↗
PubMed1995

Clentiazem and diltiazem preserve endothelium-dependent relaxation following global rat heart ischemia.

OBJECTIVE: To evaluate the effects of the calcium channel blocker diltiazem and its chloride derivative clentiazem on coronary vasoregulation of isolated rat hearts exposed to ischemia-reperfusion. Diltiazem has been reported to prevent postreperfusion myocardial damage but its beneficial effects on coronary blood-flow regulation remain uncertain. METHODS: Two groups of hearts were pretreated with a 10 min infusion of either diltiazem (10(-9) to 10(-6) mol/L) or clentiazem (10(-9) to 10(-7) mol/L) (n = 6 for each concentration) and exposed to 30 mins of no-flow ischemia. Another group (n = 6) received no pretreatment and was used as control. Endothelium-dependent and -independent relaxation were tested by assessing coronary flow increase to 5-hydroxytriptamine (10(-6) mol/L) and sodium nitroprusside (10(-5) mol/L) infusions, respectively, and were assessed before and after ischemia-reperfusion. Left ventricular pressure, dP/dt and coronary basal flow were also recorded. Postreperfusion results are expressed as a percentage of pre-ischemic value. Dunnet variance analysis was used to compare means of pretreated groups with the control group. RESULTS: Endothelium-dependent relaxation was significantly improved with both drugs. Optimal preservation was obtained with diltiazem 10(-6) mol/L (66 +/- 4%) and clentiazem 10(-7) mol/L (83 +/- 4%), whereas endothelial response was almost abolished in control hearts (6 +/- 11%, P < 0.01). Clentiazem was found to be more potent than diltiazem at low concentration (10(-9) mol/L, clentiazem 89 +/- 13% versus diltiazem 3 +/- 16%, P < 0.05). Optimal endothelium-independent relaxation preservation was achieved at 10(-8) mol/L in both groups (diltiazem 86 +/- 4%, clentiazem 82 +/- 8%, control 47 +/- 10%, P < 0.05). Left ventricular pressure and dP/dt were not affected by any pretreatment. However, postreperfusion coronary basal flow was significantly increased in control hearts. CONCLUSION: This study indicated that pre-ischemic infusion of diltiazem and clentiazem enhances endothelium-dependent and -independent coronary artery relaxation following reperfusion in the isolated rat heart model, without affective ventricular hemodynamics, and contributes to preservation of coronary artery autoregulation.

Animals↗
PubMed1995

2,3-Butanedione monoxime preserves coronary artery endothelium-dependent relaxation during myocardial ischemia in the isolated rat heart.

OBJECTIVE: To evaluate the potential benefit of 2,3-butanedione monoxime (BDM) in preserving endothelium-dependent coronary artery relaxation during myocardial ischemia. MATERIALS AND METHODS: Langendorff-perfused rat heart model. Endothelium-dependent and independent relaxations were tested with infusion of 5-hydroxytryptamine (10(-6) mol/L) and sodium nitroprusside (10(-5) mol/L), respectively. Four groups of hearts (n = 6) were used. Group 1 was perfused with BDM (25 mmol/L) without ischemia for 30 mins. Group 2 was perfused for 10 mins with BDM and exposed to 30 mins of no flow ischemia (37 degrees C). Group 3 was perfused with cold (4 degrees C) nonoxygenated BDM (30 mins) and group 4 (control) was exposed to 30 mins of no flow ischemia alone. Left ventricular pressure (LVP), left ventricular pressure first derivative (dP/dt) and coronary basal flow were evaluated before treatment and after 30 mins of reperfusion. RESULTS: BDM perfusion alone (group 1) did not affect coronary reactivity. Preservation of endothelium-dependent and -independent relaxation was significantly enhanced after ischemia in groups 2 and 3 (BDM-treated) compared with group 4 (control). No significant benefit was found regarding LVP and dP/dt in all groups. Postreperfusion coronary flow was decreased in all hearts except the controls (group 4), suggesting a residual BDM intrinsic effect on coronary flow. CONCLUSION: These experiments suggest that BDM can enhance preservation of coronary artery endothelium-dependent and -independent relaxation during myocardial ischemia in the isolated rat heart.

Animals↗
PubMed1995

Effects of modified St Thomas' Hospital solution on coronary artery endothelium dependent relaxation in the isolated rat heart.

Addition of magnesium to a preservation solution such as St Thomas's Hospital solution has been shown to improve myocardial preservation. High concentration of magnesium can affect coronary artery endothelial-dependent relaxation. Isolated rat hearts were studied in the Langendorff apparatus to investigate whether magnesium-enriched hyperkalemic cardioplegic solution (HCS) could alter coronary endothelial function. Hearts in group 1 (n = 8) were perfused for 30 mins with a standard hyperkalemic cardioplegic solution (potassium chloride 24 mmol/L). Hearts in group 2 (n = 8) were perfused with modified St Thomas' Hospital solution (MST) containing 16 mmol/L of magnesium chloride and 24 mmol of potassium chloride. The endothelium dependent and endothelium independent relaxation of the coronary arteries were respectively assessed by infusing 5-hydroxytryptamine (5-HT) (1 x 10(-6) mol/L) and sodium nitroprusside (SNP) (1 x 10(-5) mol/L) before and after perfusion of cardioplegic solutions. Hearts in group 2 showed a reduction of the 5-HT-induced coronary flow increase following the MST exposure (before, 8.66 +/- 0.86 mL/min; after, 5.66 +/- 0.97 mL/min, P < 0.01) whereas hearts in group 1 were not significantly affected (before, 8.00 +/- 0.68 mL/min; after, 6.99 +/- 1.02 mL/min, not significant), suggesting endothelial dysfunction in the former. Coronary flow response to SNP was not affected in either group.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

[Effects of cyclosporine A on the reactivity of the aorta with regenerated endothelium in rats].

Cyclosporine A (CyA) affects vascular reactivity but its effect on local vascular tone following endothelial regeneration is unknown. Experiments were designed to study the effects of CyA on endothelial and smooth muscle reactivity of endothelium-regenerated arteries. Three groups of rats (n = 8) were subjected to aortic mechanical denudation. Subsequently a first group was treated 8 weeks with CyA (20 mg/kg) and a second one with an equivalent volume of CyA vehicle: olive oil (OL). A last group was submitted to a standard diet and represented the control group (CTL). After 8 weeks, aortic rings were suspended in organ chambers for assessment of endothelial and smooth muscle function. Maximal endothelial dependent relaxation to acetylcholine (CyA: 52 +/- 3%, OL: 50 +/- 4%, CTL: 48 +/- 5%; p = NS), adenosine diphosphate (CyA: 30 +/- 7%, OL: 18 +/- 2%, CTL: 24 +/- 5%; p = NS) and histamine (CyA: 38 +/- 6%, OL: 43 +/- 4%, CTL: 47 +/- 5%; p = NS) were comparable among all groups. In aortic segments studies without endothelium, increased contraction to serotonine was significantly lessened in the OL group (CyA: 259 +/- 43%, OL: 153 +/- 11%, CTL: 243 +/- 24%; p < 0.05). Maximal tension to cumulative doses of norepinephrine was increased in rings without endothelium treated with CyA (CyA: 5.8 +/- 0.6 g, OL: 4.2 +/- 0.5 g, CTL: 4.0 +/- 0.2 g; p < 0.05). All these differences were abolished in rings studied with endothelium. Endothelial independent relaxation to sodium nitroprusside were similar among all groups. In conclusion, CyA does not specifically affect endothelium-dependent relaxation of the regenerated aortic endothelium. However, our model suggests that CyA increases vascular tone mediated by increased smooth muscle sensitivity to norepinephrine and serotonine but these effects are prevented by the regenerated endothelium. This experiment demonstrates the ability of the regenerated endothelium to prevent CyA-induced vascular toxicity.

Animals↗
PubMed1995

[In vitro endothelial dysfunction after cold storage: comparison with various preservative solutions].

Optimal solution for endothelial function preservation during cold storage for organ transplant has not yet been defined. To assess this issue, rat aortic rings (n = 28) were stored for 4 hours at 4 degrees C in different preservation solutions: Krebs Ringer (KR), normal saline (NS), rat blood (RB), and the University of Wisconsin solution (UW). Subsequently, rings were suspended in organ chambers for endothelial and smooth muscle assessment. Endothelial-dependent relaxation responses were tested by exposure to cumulative doses of acetylcholine (ACH), adenosine diphosphate (ADP), and histamine (HIS). Smooth muscle function was evaluated by exposure to norepinephrine (NE) and sodium nitroprusside (SNP). A fifth group not submitted to a storage period was used as control (CTL, n = 7). Results are expressed as maximal relaxation (%) from initial precontraction level. Compared to the CTL group, all storage groups showed a significant decrease in endothelial-dependent relaxations to ACH, ADP and HIS (p < 0.05). Among the stored groups, endothelial-dependent relaxation to ACH was significantly decreased in the NS group when compared to the UW group (p < 0.05). Endothelial-independent relaxation to SNP was comparable for all groups. However significant hypercontractility to NE was observed for all stored groups compared to the control group (p < 0.01). A significant decrease in ADP response was observed with NS and RB storage when compared to KR (p < 0.01). In conclusion, cold storage affects both endothelial and smooth muscle function by decreasing endothelial-dependent responses to ACH, ADP and HIS and increasing smooth muscle reactivity to NE. However, endothelial dysfunction was lessened with UW or KR storage compared to NS or RB.

Adenosine↗
PubMed1994

Chronic exposure to cyclosporine affects endothelial and smooth muscle reactivity in the rat aorta.

Chronic exposure to cyclosporine affects vascular reactivity. Experiments were designed to characterize the endothelium-dependent and endothelium-independent vascular reactivity of rats exposed to oral cyclosporin A (CyA). Two subsets of rats (n = 6) were treated with CyA (20 mg/kg/day) and olive oil (cyclosporine vehicle), respectively, for a period of 8 weeks. Aortic rings (4-5 mm) were suspended for isometric force measurement in organ chambers containing Krebs Ringer solution (37 degrees C, 95% O2, 5% CO2). The maximal endothelium-dependent relaxation to cumulative doses of acetylcholine was significantly decreased in the CyA-treated aortic rings compared to olive oil-treated ones (data expressed as percent of initial contraction; CyA, 50% +/- 3% versus olive oil, 37% +/- 7%; p < 0.05). However, endothelium-dependent relaxations to histamine and adenosine diphosphate and endothelium-independent relaxation to sodium nitroprusside were not affected in both groups. An endothelium-dependent contraction to serotonin and aggregating platelets were observed in the CyA group, but not in the control group. The endothelium-independent contraction to norepinephrine was enhanced in the CyA group (CyA ED50, log -7.66 +/- 0.18 mol/L versus olive oil ED50, log -7.01 +/- 0.11 mol/L; p < 0.01). These experiments suggest that chronic exposure to cyclosporine A could contribute to augmenting vascular tone by (1) decreased release of endothelial relaxing factor mediated by muscarinic receptors, (2) increased production of endothelium-related constricting factor mediated by serotoninergic receptors, and (3) greater vascular smooth muscle sensitivity to circulating catecholamine.

Acetylcholine↗
PubMed1993

Effects of University of Wisconsin solution on endothelium-dependent coronary artery relaxation in the rat.

University of Wisconsin (UW) solution has been reported to enhance myocardial preservation in heart transplantation. To evaluate the effects of UW solution on coronary artery endothelial function, we designed experiments to compare UW solution with a standard crystalloid hyperkalemic cardioplegic solution (CHCS). Isolated rat hearts were studied in a modified Langendorff apparatus for coronary endothelial function. Groups 1 and 2 were perfused with 4 degrees C CHCS (24 mmol/L of KCl) and UW solution, respectively, for 10 minutes at a pressure of 80 cm H2O, whereas group 3 underwent warm ischemia for 10 minutes. Groups 4 and 5 were perfused with and stored for 4 hours in cold (4 degrees C) CHCS and UW solution, respectively. Group 6 underwent 4 hours of topical cooling (4 degrees C) without any cardioplegic perfusion. All groups had 6 hearts each. Endothelium-dependent relaxation and endothelium-independent relaxation of the coronary arteries were tested by infusing 5-hydroxytryptamine (5HT) (10(-6) mol/L) and sodium nitroprusside (10(-5) mol/L), respectively, before and after perfusion with and storage in one of the two cardioplegic solutions. The coronary vasodilatation induced by 5HT and sodium nitroprusside was not altered in hearts perfused with (group 1) or perfused with and stored in CHCS (group 4). Coronary flow increase after 5HT infusion was significantly decreased in hearts perfused with (group 2) (before, 35% +/- 10%; after, 13% +/- 10%; p < 0.01) or perfused with and stored in UW solution (group 5) (before, 34% +/- 5%; after, -5% +/- 12%), indicating severe endothelial dysfunction.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine↗
PubMed1993

The role of preservation solutions in coronary endothelial damage during cold storage.

The effects of cold storage and type of preservation solution on coronary endothelial function are not well understood. Experiments were designed to evaluate coronary endothelial-dependent relaxation after a 4-hr cold (4 degrees C) storage in different preservation solutions. Isolated rat hearts were studied in the Langendorff apparatus for coronary endothelial function. After 30 min of stabilization, hearts were arrested with a 10-min perfusion of 4 degrees C crystalloid hyperkalemic cardioplegic solution (CHCS) containing 24 mmol/L of KCl and stored for 4 hr in the following preservation solutions: CHCS, Krebs-Ringer's solution (KR), 0.9% NaCl (NS), and University of Wisconsin solution (UW). A fifth group was perfused and stored in UW solution. Endothelial-dependent and independent coronary artery vasorelaxation were tested, respectively, by infusing 5-hydroxytryptamine (5-HT) (1 x 10(-6) mol/L) and sodium nitroprusside (SNP) (1 x 10(-5) mol/L) before and 30 min after the storage period. In hearts stored in CHCS and KR, the coronary artery flow increase to 5-HT and SNP infusion were not significantly affected. However, in hearts preserved with NS and UW solutions, 5-HT coronary response was significantly decreased, indicating endothelial dysfunction. In addition to these findings, coronary flow increase to SNP infusion was decreased in the group perfused and stored with UW, suggesting smooth muscle damage. These experiments suggest that 4-hr cold storage in NS or UW impairs endothelial-dependent coronary relaxation in the isolated rat heart model.

Adenosine↗
PubMed1993

[Effect of different solutions of preservatives on the endothelial function of coronary arteries in rats].

The effects of cold storage and type of preservation solution on coronary endothelial function are not well established. Experiments were designed to evaluate coronary endothelial-dependent relaxation after a 4-hour cold (4 degrees C) storage in different preservation solutions. Rat hearts, mounted in the Langendorff apparatus, were arrested with a 10-minute perfusion of 4 degrees C crystalloid hyperkaliemic cardioplegic solution (CHCS) (KCl 24 mEq/l) and stored for 4 hours in the following preservation solutions: CHCS (n = 6), Krebs-Ringer solution (KR) (n = 6), 0.9% NaCl (NS) (n = 6) and the University of Wisconsin solution (UW) (n = 6). A fifth group (n = 6) was perfused and stored in UW solution. Endothelium-dependent and independent coronary artery vasorelaxations were respectively tested by infusing 5-hydroxytryptamine (5-HT) (10(-6) mol/l) and sodium nitroprusside (SNP) (10(-5) mol/l) before and after the storage period. In hearts stored with CHCS or KR, coronary artery flow increase to 5-HT and SNP infusions were not significantly affected. However, in hearts preserved with NS or UW solutions, 5-HT coronary response was significantly decreased, indicating endothelial dysfunction. In addition to these findings, coronary flow increase to SNP infusion was decreased in the group perfused and stored with UW, suggesting smooth muscle dysfunction. These experiments suggest that 4-hour cold storage in NS or UW impairs endothelial-dependent coronary relaxation in the isolated rat heart model.

Adenosine↗
PubMed1993

[Magnetic resonance imaging in the diagnosis and follow-up of false aneurysms after Bentall's operation].

The prevalence and natural history of pseudo-aneurysm (PA) following Bentall procedure has not been established. To determine the follow-up of such patients, we report our experience with magnetic resonance imaging (MRI) used since 1988. At first, spin-echo exam, PA was suspected in 19 patients among 27 patients who underwent aortic valve and ascending aortic replacement between 1980 and 1991. Mean PA diameter was < 4 cm in 13 patients (group 1) and > or = 4 cm in six patients (group 2). Two patients of group 1 were lost at follow-up while two others died after the first spin-echo exam, one death being related to PA formation. Repeated MRIs were done in nine patients of group 1 and all patients of group 2 averaging respectively 2.2 +/- 1.1 exams per patient for group 1 and 1.8 +/- 1.1 for group 2. PA regressed in six patients of group 1 and one patient of group 2 thus suggesting thrombosed PA or postoperative haematoma. PA remained stable in two patients of group 1 and one patient of group 2. One patient of group 1 in whom PA increased at follow-up died suddenly. Four patients of group 2 required surgical correction of their PA. One of these patients died of massive hemoptysis 2 months following reintervention. Recently, addition of cine MRI allows visualization of turbulent flow within the PA thus increasing MRI specificity for PA diagnosis.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Pseudoaneurysm after Bentall repair: magnetic resonance imaging assessment.

The prevalence and natural history of pseudoaneurysms (PA) following Bentall procedure has not been established. To determine the follow-up of PA in patients, the authors report their experience with magnetic resonance imaging (MRI) since 1988. Spin-echo technique suspected PA in 19 of the 27 patients who underwent aortic valve and ascending aortic replacement between 1980 and 1991. Mean PA diameter was less than 4 cm in 13 patients (group 1) and at least 4 cm in six patients (group 2). Two patients in group 1 were lost at follow-up while two others in this group died after first spin-echo examination (one death was related to PA formation). Repeated MRIs were thus possible in nine patients in group 1 and in all patients in group 2, averaging 2.2 +/- 1.1 examinations per patient for group 1 and 1.8 +/- 1.1 for group 2. PA assessed in six group 1 patients and one group 2 patient suggested thrombosed PA or postoperative hematoma. PA remained stable in two group 1 patients and one group 2 patient. One patient from group 1, in whom PA increased at follow-up, died suddenly. Four patients in group 2 required correction of PA, which had increased in diameter. Recently, addition of cine MRI has allowed visualization of turbulent flow within PA, thus increasing MRI specificity for PA diagnosis. In conclusion, MRI constitutes a reliable noninvasive imaging technique for diagnosis and follow-up of PA after Bentall repair.

Aortic Dissection↗
PubMed1992

[The intermittent "warm" blood cardioplegia].

Even today, a plethora of cardioplegic solutions are in clinical use. In the study presented here, sixty-six consecutive coronary bypass procedures received normothermic (37 degrees C) blood cardioplegia (NBC) intermittently. This group of patients was compared to an historical group of 68 patients having received cold crystalloid cardioplegia (CCC), and a second group of 41 patients having received cold blood (10 degrees C) cardioplegia (CBC). The number of patients, as well as their age, sex, functional class, ejection fraction and urgency of intervention were comparable between the three groups. The preoperative use of inotropic drugs was less prevalent in the normothermic blood cardioplegia group (NBC 24% v. CCC 52% and CBC 51%, p < 0.05), as was the use of a pacemaker (NBC 8% v. CCC 52% and CBC 51%, p < 0.02). Finally, the rates of myocardial infarction and mortality were comparable between the three groups. These results suggest that normothermic blood cardioplegia is efficient in reducing the demand in O2, by inducing the electromechanical arrest of the heart and, that intermittent normothermic blood cardioplegia can be safe and effective.

Aged↗
PubMed1989

Metabolism of leukotriene C4 in the anesthetized guinea pig.

The distribution and metabolism of [3H] leukotriene (LT)C4 has been studied in the anesthetized guinea pig. The intravenous administration of [3H] LTC4 (1 muCi/kg) to seven guinea pigs showed a rapid vascular clearance of radioactivity with significant metabolism evident at the 15 sec and 1 min time points with material chromatographing like LTC4 (45.6 +/- 7.5%, 35.0 +/- 4.4%). LTD4 (18.4 +/- 5.1%, 33.2 +/- 4.4%) as well as polar material (25.5 +/- 6.0%, 29.7 +/- 4.7%) respectively. The biliary recovery of radioactivity was found to be 74.5 +/- 5.5% n = 4, over 120 min in the guinea pig with less than 1% of radioactivity present in the urine. Examination of the metabolic profile of the biliary radioactivity showed total conversion of LTC4 to LTD4 which was the major metabolite at early time points, and LTD4 as well as LTE4 at later time points. Significant radioactivity which increased with time was also present at the solvent front of the chromatogram indicating the presence of polar biliary metabolites. These results show that the major route of elimination of peptide leukotrienes is through the bile duct in the anesthetized guinea pig and that LTD4 is the major eliminated metabolite in this model.

Anesthesia↗