Biomedical subjects

L Normandin

Publications and source records attributed to L Normandin.

18 recordsLinked to original sources

PubMed2001

Bioaccumulation and locomotor effect of manganese dust in rats.

The primary goal of this study is to determine the effects of Mn exposure via inhalation. The bioaccumulation of Mn in different organs and tissues, the alteration of biochemical parameters, and the locomotor activity were assessed. A group of 26 male Sprague-Dawley rats (E) were exposed to 3750 microg/m(3) of Mn dust for 6 h/day, 5 days/wk for 13 consecutive weeks and compared to a control group of 12 rats (C) exposed to 4 microg/m(3). After exposure, neurological evaluation was carried out for 36 h (a night-day-night cycle) using a computerized autotrack system. Rats were then sacrificed by exsanguination, and Mn content in organs and tissues was determined by neutron activation analysis. Mn concentrations in lung, putamen, and cerebellum were significantly higher in E than in C (0.30 vs. 0.17, 0.89 vs. 0.44, 0.63 vs. 0.48 ppm; p <.01), as well as in the kidney, frontal cortex, and globus pallidus (1.15 vs. 0.96, 0.84 vs. 0.47, 1.28 vs. 0.55 ppm; p <.05). Potassium concentration was significantly lower in E than in C (5.11 vs. 5.79 mmol/L; p <.05), as was alkaline phosphatase (106.9 vs. 129.6 U/L; p <.01). Locomotor activity indicated higher distance covered in the first 12-h period for E (45 383 vs. 36 098 cm; p <.05) and lower resting time in the last 12-h period for E (36 326 vs. 37 393 s; p <.05). This study is the first of several ongoing studies in our laboratory that address health concerns associated with inhalation exposure to different Mn species and to different levels of exposure.

Administration, Inhalation↗

PubMed2001

Assessment of bioaccumulation and neurotoxicity in rats with portacaval anastomosis and exposed to manganese phosphate: a pilot study.

The use of the additive methylcyclopentadienyl manganese tricarbonyl in unleaded gasoline has resulted in increased attention to the potential toxic effects of manganese (Mn). Hypothetically, people with chronic liver disease may be more sensitive to the adverse neurotoxic effects of Mn. In this work, bioaccumulation of Mn, as well as histopathology and neurobehavioral damage, in end-to-side portacaval anastomosis (PCA) rats exposed to Mn phosphate via inhalation was investigated. During the week before the PCA operation, 4 wk after the PCA operation, and at the end of exposure, the rats were subjected to a locomotor evaluation (day-night activities) using a computerized autotrack system. Then a group of 6 PCA rats (EXP) was exposed to 3050 microg m(-3) (Mn phosphate) for 8 h/day, 5 days/wk for 4 consecutive weeks and compared to a control group (CON), 7 PCA rats exposed to 0.03 microg m(-3). After exposure, the rats were euthanized and Mn content in tissues and organs was determined by neutron activation analysis. The manganese concentrations in blood (0.05 microg/g vs. 0.02 microg/g), lung (1.32 microg/g vs. 0.24 microg/g), cerebellum (0.85 microg/g vs. 0.64 microg/g), frontal cortex (0.87 microg/g vs. 0.61 microg/g), and globus pallidus (3.56 microg/g vs. 1.33 microg/g) were significantly higher in the exposed group compared to the control group (p <.05). No difference was observed in liver, kidney, testes, and caudate putamen between the two groups. Neuronal cell loss was assessed by neuronal cell counts. The loss of cells in globus pallidus and caudate putamen as well as in frontal cortex was significantly higher (p <.05) for the EXP group. Assessment of the locomotor activities did not reveal any significant difference. This study constitutes a first step toward our understanding of the potential adverse effects of Mn in sensitive populations.

Administration, Inhalation↗

PubMed2000

Impact of routine use of intraoperative transesophageal echocardiography during cardiac surgery.

PURPOSE: To determine the relative impact of each category-based TEE indication according to the ASA guidelines. METHODS: In 851 patients undergoing cardiac surgery, TEE clinical indications were classified as category I or II according to the ASA guidelines. Category I indications are patients in which TEE is considered useful and category II are those where TEE is potentially useful but indications are less clear. All TEE examinations were reviewed by two anesthesiologists with advanced training in TEE. For each patient, the clinical impact of TEE in the clinical management was assessed using five criteria: 1) change of medical therapy; 2) change in the surgical procedure; 3) confirmation of a suspected diagnosis; 4) positioning of an intravascular device, and 5) substitute to a pulmonary artery catheter (PAC). RESULTS: TEE had greater utility in category I than in category II indications (15/53 (28%) vs. 110/798 (14%) respectively) (P<0.01). The nature of the clinical impact was as follows: modification of medical therapy in 67/125 (53%), modification of planned surgical intervention in 38/125 (30%), confirmation of a diagnosis in 34/125 (27%). The impact on therapy was higher in complex surgical procedures (39%) than in valvular replacement (19%) (P<0.01) and coronary artery bypass surgery (10%) (P<0.001). CONCLUSIONS: Our findings validate the usefulness of the ASA practice guidelines demonstrating a greater impact of TEE on clinical management for category I indications than for category II. TEE also had a greater clinical impact in complex surgical procedures and in valvular replacement.

Cardiac Surgical Procedures↗

PubMed1999

Potential of dandelion (Taraxacum officinale) as a bioindicator of manganese arising from the use of methylcyclopentadienyl manganese tricarbonyl in unleaded gasoline.

Methylcyclopentadienyl manganese tricarbonyl (MMT) is an organic manganese (Mn) compound currently added to unleaded gasoline in Canada. It has been suggested that the combustion of MMT containing Mn could cause various deleterious health effects in animals and humans at very high concentrations. This study evaluates the potential of dandelions (Taraxacum officinale) as bioindicators of Mn environmental contamination. Samples were picked at three different distances from a highway: a highly exposed site (E++), a lightly exposed site (E+) and a control site (E), located respectively at 10, 50 and 100 m. The total Mn, Mg, Ca, Al, Fe and Zn concentrations were measured in the soils and in the plants (flower, stem, leaves and root) by neutron activation analysis. Exchangeable Mn was measured in soils by atomic absorption spectrophotometry. Mn concentrations of the different parts of the plant and exchangeable Mn in soils were not correlated with distance from the roadway and, thus, do not seem to be a sensitive indicator of Mn contamination. Soil Mn concentrations were correlated with distance from the roadway. This suggests the hypothesis that the environmental fate of Mn from MMT sources could be associated with an increased total Mn in soil but does not lead to an increase in exchangeable Mn.

Air Pollutants↗

PubMed1999

Manganese deposition in basal ganglia structures results from both portal-systemic shunting and liver dysfunction.

BACKGROUND & AIMS: Manganese (Mn) deposition could be responsible for the T(1)-weighted magnetic resonance signal hyperintensities observed in cirrhotic patients. These experiments were designed to assess the regional specificity of the Mn increases as well as their relationship to portal-systemic shunting or hepatobiliary dysfunction. METHODS: Mn concentrations were measured in (1) brain samples from basal ganglia structures (pallidum, putamen, caudate nucleus) and cerebral cortical structures (frontal, occipital cortex) obtained at autopsy from 12 cirrhotic patients who died in hepatic coma and from 12 matched controls; and from (2) brain samples (caudate/putamen, globus pallidus, frontal cortex) from groups (n = 8) of rats either with end-to-side portacaval anastomosis, with biliary cirrhosis, or with fulminant hepatic failure as well as from sham-operated and normal rats. RESULTS: Mn content was significantly increased in frontal cortex (by 38%), occipital cortex (by 55%), pallidum (by 186%), putamen (by 66%), and caudate (by 54%) of cirrhotic patients compared with controls. Brain Mn content did not correlate with patient age, etiology of cirrhosis, or history of chronic hepatic encephalopathy. In cirrhotic and portacaval-shunted rats, Mn content was increased in pallidum (by 27% and 57%, respectively) and in caudate/putamen (by 57% and 67%, respectively) compared with control groups. Mn concentration in pallidum was significantly higher in portacaval-shunted rats than in cirrhotic rats. No significant changes in brain Mn concentrations were observed in rats with acute liver failure. CONCLUSIONS: These findings suggest that brain Mn deposition results both from portal-systemic shunting and from liver dysfunction.

Animals↗

PubMed1998

Estimation of the pulmonary capillary wedge pressure from transesophageal pulsed Doppler echocardiography of pulmonary venous flow: influence of the respiratory cycle during mechanical ventilation.

OBJECTIVE: Pulsed Doppler measurement of pulmonary venous flow (PVF) in the left superior pulmonary vein has been suggested as a noninvasive method to evaluate pulmonary capillary wedge pressure (PCWP). In previous studies, PVF was measured at end-expiration, and it is unknown to what extent PVF is affected by the respiratory cycle. It is hypothesized that phasic variations of PVF during mechanical ventilation may be used to estimate PCWP. DESIGN: Prospective clinical study. SETTING: Tertiary care university hospital. PARTICIPANTS: Thirty patients undergoing elective cardiac surgery. INTERVENTIONS: At multiple intervals during the surgery, the PVF was measured with transesophageal pulsed Doppler echocardiography, and measurements of PCWP and airway pressure were simultaneously obtained. MEASUREMENTS AND RESULTS: Components of PVF evaluated were the systolic (X), diastolic (Y), and atrial (Z) waves with their velocity-time integrals (VTI). The systolic fraction (SF = VTI X/[VTI X + VTI Y]) and respiratory variations of each component of PVF were determined and compared with PCWP. There was a greater respiratory variation of the X wave (X expiratory-X inspiratory/X expiratory) in patients with PCWP < 18 mmHg than in patients with PCWP > or = 18 mmHg (0.19 +/- 0.19 v 0.14 +/- 0.13, respectively, p < 0.01). PVF components measured at end-expiration that related best with PCWP were the X/Y peak velocities (r = -0.53), VTI X/VTI Y ratio (r = -0.42), and the SF (r = -0.49). When measured during end-inspiration, the relation of the X/Y ratio, VTI X/VTI Y, and SF with the PCWP were r = -0.54, r = -0.41, and r = -0.50, respectively. CONCLUSIONS: It has been documented that PVF velocity is influenced by the respiratory cycle during mechanical ventilation in patients undergoing cardiac surgery, and the magnitude of this variation is influenced by PCWP. However, it is not actually possible to predict PCWP accurately using these findings. Further studies are needed in which preload is varied acutely to confirm the usefulness of the results.

Adult↗

PubMed1998

Role of manganese in the pathogenesis of portal-systemic encephalopathy.

Amongst the potential neurotoxins implicated in the pathogenesis of hepatic encephalopathy, manganese emerges as a new candidate. In patients with chronic liver diseases, manganese accumulates in blood and brain leading to pallidal signal hyperintensity on T1-weighted Magnetic Resonance (MR) Imaging. Direct measurements in globus pallidus obtained at autopsy from cirrhotic patients who died in hepatic coma reveal 2 to 7-fold increases of manganese concentration. The intensity of pallidal MR images correlates with blood manganese and with the presence of extrapyramidal symptoms occurring in a majority of cirrhotic patients. Liver transplantation results in normalization of pallidal MR signals and disappearance of extrapyramidal symptoms whereas transjugular intrahepatic portosystemic shunting induces an increase in pallidal hyperintensity with a concomitant deterioration of neurological dysfunction. These findings suggest that the toxic effects of manganese contribute to extrapyramidal symptoms in patients with chronic liver disease. The mechanisms of manganese neurotoxicity are still speculative, but there is evidence to suggest that manganese deposition in the pallidum may lead to dopaminergic dysfunction. Future studies should be aimed at evaluating the effects of manganese chelation and/or of treatment of the dopaminergic deficit on neurological symptomatology in these patients.

Brain↗

PubMed1998

Suicidal children grow up: relations between family psychopathology and adolescents' lifetime suicidal behavior.

Standard family history and family study methods were used with 650 first- and 1174 second-degree biological relatives of 133 adolescents who were studied initially 6 to 8 years ago. They included 69 prepubertal children considered at risk for suicidal behavior and 64 prepubertal children selected from the community. This study aimed to identify relationships between family psychopathology and adolescents' lifetime history of suicidal states. Family discord, suicide attempts of mother, and substance abuse of mothers and fathers were significantly more prevalent among adolescents with lifetime history of a suicide attempt. Mothers' and fathers' substance abuse was associated with adolescents' lifetime history of suicidal ideation. Results highlight importance of evaluating and treating family psychopathology to reduce risk for youth suicidal states.

Adolescent↗

PubMed1998

The Children's Play Therapy Instrument (CPTI). Description, development, and reliability studies.

The Children's Play Therapy Instrument (CPTI), its development, and reliability studies are described. The CPTI is a new instrument to examine a child's play activity in individual psychotherapy. Three independent raters used the CPTI to rate eight videotaped play therapy vignettes. Results were compared with the authors' consensual scores from a preliminary study. Generally good to excellent levels of interrater reliability were obtained for the independent raters on intraclass correlation coefficients for ordinal categories of the CPTI. Likewise, kappa levels were acceptable to excellent for nominal categories of the scale. The CPTI holds promise to become a reliable measure of play activity in child psychotherapy. Further research is needed to assess discriminant validity of the CPTI for use as a diagnostic tool and as a measure of process and outcome.

Affect↗

PubMed1998

[Cardiac surgery in renal transplant patients. Apropos of 24 cases].

UNLABELLED: Results of cardiac surgery in renal transplant patients are not well documented. Immunosuppression as well as associated conditions in these patients, and the increased susceptibility of the renal allograft to the extracorporeal circulation (ECC) may alter the prognosis of renal transplant patients submitted to cardiac surgery. To evaluate this hypothesis, we reviewed the files of 24 patients (18 Male, 6 Female; age: 49 +/- 12 years) operated under ECC between 1978 and 1997. Twenty patients underwent coronary artery bypass surgery, 5 patients a valve replacement procedure (aortic and/or mitral), and one patient necessitated a Cabrol procedure for an ascending aorta aneurysm. Preoperatively, the majority of patients were in functional class (NYHA) IV (16 patients), and ejection fraction was > 50% in 18 patients. Two operative deaths secondary to cardiogenic shock were encountered. Five patients (23%) were reoperated for bleeding; 5 patients (23%) sustained a major infection (2 pneumonias, 2 mediastinitis and one wound infection) resulting in death in one patient; 5 patients (23%) were treated for arythmia; and 2 patients (9%) suffered a perioperative myocardial infarction. Serum creatinine levels did not increase significantly during hospitalization (p = 0.41 between extreme values). Mean follow-up (41 +/- 28 months) of the 20 survivors revealed recurrent angina in 5 patients and late death in 4 patients, cardiac-related in 3 cases. CONCLUSION: Cardiac surgery in renal transplant patients is subjected to a high morbidity and mortality. Mid-term prognosis is reserved especially in presence of associated conditions.

Angina Pectoris↗

PubMed1995

L-arginine and pentoxifylline attenuate endothelial dysfunction after lung reperfusion injury in the rabbit. The Paris-Sud University Lung Transplant Group.

BACKGROUND: Among the factors involved in the early complications of lung transplantation is the ischemia-reperfusion syndrome related to a warm reperfusion in ischemic lungs. METHODS: Using an isolated rabbit lung preparation perfused with whole blood, we studied the effects of cold ischemia followed by a warm reperfusion on pulmonary vascular responses to reproduce experimentally the conditions encountered during lung transplantation. RESULTS: Pulmonary vascular responses to acetylcholine were rapidly altered by warm ischemia (relaxation of 7% versus 60% in controls). Conversely, relaxation was maintained even after a prolonged cold ischemic storage (maximal relaxation of 57% at 48 hours). Warm reperfusion in ischemic lungs induced major alteration of endothelium-dependent relaxation (maximal relaxation of 13% at 4 hours). The addition of L-arginine or pentoxifylline during reperfusion prevented the pulmonary endothelial alteration resulting from warm reperfusion. CONCLUSION: These data suggest that treatments aimed at maintaining intact functional endothelium reduce ischemia-reperfusion injury in transplanted lungs.

Acetylcholine↗

PubMed1995

Countertransference as instrument and obstacle: a comprehensive and descriptive framework.

A comprehensive and descriptive approach to counter-transference phenomena is proposed. Three types of mental activity are distinguished: the objective-rational attitude is an adaptive, relatively nondefensive mode of observation; the reactive mental state corresponds to the classical notion of unconscious counter-transference as an obstacle and a defense; by contrast the reflective attitudes involve preconscious and conscious psychical activity. Reflective activity involves four phases: (1) during emergence, an inner reaction appears; (2) immersion, through a regressive exploration, leads to introjective identification; (3) integrative elaboration involves a shift in cathexis, more distance, and an organization of the regressed contents, while (4) an interpretation is forming in mind. Three case examples from the literature serve to illustrate.

Countertransference↗

PubMed1994

Suicidal children grow up: suicidal behavior and psychiatric disorders among relatives.

OBJECTIVE: This paper reports comprehensive data on psychiatric symptoms and disorders and medical problems of first- and second-degree biological relatives of prepubertal children who have contemplated or attempted suicide. METHOD: Standard family study and family history interview techniques were used to obtain information about psychopathology and medical illness in 488 first- and 1,062 second-degree relatives of 25 child psychiatric inpatients who reported suicide attempts, 28 child psychiatric inpatients who contemplated suicide, 16 nonsuicidal child inpatients, and 54 normal children. RESULTS: Suicidal behavior in children was associated with suicidal behavior in their families, although no first-degree relatives committed suicide. More first-degree relatives of child suicide attempters, compared to first-degree relatives of normal children, had antisocial personality disorder, assaultive behavior, and substance abuse. Mood disorders in first-degree relatives were not associated with child suicidal behavior. No significant associations were identified for psychopathology of second-degree relatives and child suicidal behavior. CONCLUSIONS: The results suggest the importance of evaluating familial psychopathology during assessments of suicidal children. Self-directed and externally directed violence, antisocial personality disorder, and substance abuse of relatives of suicidal children should be studied to elucidate the etiology of youth suicidal behavior.

Adolescent↗

PubMed1992

[Palliative treatment with an endoluminal prosthesis for obstruction of the esophagus and the cardia].

Between December 1984 and September 1991, a total of 68 palliative esophageal intubations were performed in 57 patients. The mean age was 64 years, there were 40 males and 17 females. The more frequent causes of esophageal obstruction were malignant tumors of the esophagus (49%), lung (23%) and cardia (19%). Total dysphagia (24.5%), dysphagia to liquids (47%) and esophagotracheal aspiration (14%) were present in these patients. In 65% of patients insertion of the prosthesis was the first attempt at palliation, in the remaining patients it followed the failure of another type of palliation. The decision to palliate esophageal obstruction was established preoperatively in 86% of patients, in the remaining 14% it was decided at the time of surgery. The intubation by pulsion (Atkinson) [1] was successful in 57% of patients and by traction (Celestin) [2] in 86% of patients. The associated morbidity was 36% for the Atkinson prosthesis and 13% for the Celestin prosthesis, although the latter required a laparotomy. The in hospital mortality was 12.5%. The mean survival was 85 days. A normal or semi-solid diet was tolerated by over 60% of patients following intubation. Palliation of esophageal obstruction by intubation improves the quality of life but is associated with a high morbidity.

Cardia↗

PubMed1992

[Salvage heart surgery after percutaneous mitral valvuloplasty].

Percutaneous mitral valvuloplasty (PMV) for selected patients with symptomatic mitral stenosis (MS) has been proposed as a safe alternative to open mitral commissurotomy (OMC) or mitral valvular replacement (MVR). Among 146 consecutive patients undergoing PMV from March 1987 to April 1990, 18 (12%) needed urgent (8) or delayed (10) (average 7 days) corrective surgery following PMV. There were 15 women and 3 men, with a clinical incapacity class II (3) or III (15), and with an intermediate risk for PMV according to echo score (mean = 8). The indications for corrective surgery were: massive mitral regurgitation due to tearing of the anterior leaflet (6), cardiac perforations (left atrium in 2, left ventricle in 3), PMV technical failure (5), severe atrial shunting (2). Operative procedures included MVR (14), cardiac wound suturing only (3), OMC (1). Operative mortality (30 days) was 22% (4/18), equally distributed among the urgent and delayed group. The causes of postoperative death were hemorrhage (2), severe cerebral ischemia (1) and sudden death (1). Compared to operative mortality after OMC (0/17.0%) or MVR (1/32, 3.1%) as the initial treatment for MS during the same time period, cardiac operation after failed or complicated PMV carried a significantly higher mortality (p = 0.004). Therefore, optimal patient selection and aggressive corrective surgery are necessary to decrease the PMV related mortality and morbidity.

Adult↗

PubMed1992

Cardiac surgery after failed percutaneous mitral valvuloplasty.

Percutaneous mitral valvuloplasty (PMV) has been proposed as a safe alternative to open mitral commissurotomy (OMC) or mitral valvular replacement (MVR) in selected patients with symptomatic mitral stenosis (MS). Among 146 consecutive patients who underwent PMV between March 1987 and April 1990, 18 (12%) needed urgent corrective surgery after the procedure. Of these 18 patients 16 were women and 2 were men. Three patients were of clinical incapacity class II and 15 of class III and were at an intermediate risk for PMV according to the echo score (mean score 8). The indications for corrective surgery were massive mitral regurgitation owing to tearing of the anterior leaflet (six patients), cardiac perforation (left atrium in two patients, left ventricle in three patients), technical failure of PMV (five patients) and severe atrial shunting (two patients). Operative procedures included MVR (14 patients), cardiac wound suturing only (3 patients) and OMC (1 patient). Operative mortality (within 30 days) was 22% (4 of 18 patients), distributed equally among patients needing urgent or elective surgery. When compared with the operative death rate after OMC (0%) and MVR (3.1%) as the initial treatment for MS during the same period, the rate for cardiac operation after failed or complicated PMV (22%) was significantly higher (p = 0.004). Therefore, optimal patient selection and aggressive corrective surgery are necessary to decrease PMV-related morbidity and death.

Adult↗

PubMed1991

[Thoracotomy with muscle sparing].

Muscle sparing thoracotomy is suggested more frequently in recent literature. From March 1988 to February 1990, a muscle sparing technique was used in 77 (58%) of 132 consecutive thoracotomies. There were 50 men and 27 women, age varied from 23 to 81 years, with a mean of 58 years. Forty-four lobectomies, 10 pneumonectomies, 9 lung biopsies, 6 wedge resections, 6 bullectomies and 2 segmentectomies were performed. A horizontal incision was used in 47 (61%) patients and a vertical mid-axillary incision in 30 (39%). For optimal exposure, transection of the latissimus dorsi muscle was needed in 14 (30%) of the horizontal incisions. Inadvertent rib fracture occurred in 10 (13%) cases. Continuous epidural analgesia was added in 46 (60%) patients for an average of 40 hours. Mechanical ventilation in 14 (18%) patients for a mean duration of 22 hours and an average stay of 2 days in the ICU and 7 days in the hospital, were required. There was 1 (1.3%) hospital mortality, 4 (5%) patients developed a seroma that required aspiration. Muscle sparing thoracotomy can be used safely for most thoracic procedures and we believe it permits easier pain control and early preservation of full shoulder motion. However the operative field is more restricted. A horizontal incision, permitting section of the latissimus dorsi for better exposure should be used for hilar or invasive lesions.

Analgesics↗

PubMed1988

[Compartment syndrome of the legs and scurvy].

Old people living alone and in poverty are most at risk for developing scurvy, but the diagnosis may be missed unless the physician is aware of it. A 42-year-old immigrant living in poverty was treated surgically at the Hôtel-Dieu Hospital in Montreal for a compartment syndrome of the leg. She had ecchymoses on the skin of the leg and an interstitial hematoma in both posterior compartments. Three weeks later, she was readmitted with more swelling in the leg, gingivitis, hemorrhagic folliculitis, petechiae and gastrointestinal hemorrhage. Her response to vitamin C was remarkable and confirmed the diagnosis of scurvy.

Adult↗