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Biomedical subjects

M Chabot

Publications and source records attributed to M Chabot.

At least 19 recordsLinked to original sources
PubMed2004

Fragmentation of highly excited small neutral carbon clusters.

We present a combined experimental and theoretical study of fragmentation of small Cn clusters (n = 5,7,9) produced in charge transfer collisions of fast (nu = 2.6 a.u.) singly charged Cn+ clusters with He. Branching ratios for all possible fragmentation channels have been measured. Comparison with microcanonical Metropolis Monte Carlo simulations based on quantum chemistry calculations allows us to determine the energy distribution of the excited clusters just after the collision.

Journal Article↗
PubMed1996

[The excision of branchial parapharyngeal cysts by transbuccal or l cervical approach].

Branchial cysts located in the parapharyngeal space are extremely rare; only seven cases were described in the literature between 1927 and today. In Quebec City, two cases were operated on during the last 3 years. Often, many antibiotic and surgical treatments have been inefficiently used, before getting to the correct diagnosis and final curative treatment. We stress the importance of a detailed evaluation of the lesion and of a noninvasive surgery. Magnetic resonance imaging is the primary imaging modality for parapharyngeal space masses, and surgical excision using the transoral approach is advantageous in selected cases.

Adolescent↗
PubMed1993

The effect of treatment with angiotensin-converting enzyme inhibitors on survival of pediatric patients with dilated cardiomyopathy.

Outcome in 81 pediatric patients with dilated cardiomyopathy was reviewed to assess whether treatment with angiotensin-converting enzyme (ACE) inhibitors affected survival. Age at onset was 3.6 +/- 0.6 years. Twenty-seven children (group 1) were treated with ACE inhibitors. Conventional therapy was used in the remaining 54 patients (group 2). There were no significant differences between the two groups in age at onset, left ventricular shortening fraction, left ventricular end-diastolic pressure, or mean pulmonary artery pressure. Patients treated with ACE inhibitors had a significantly better survival during the first year (p < 0.05) with continuation of this trend throughout the second year (p = 0.06). Beyond 2 years there was a tendency toward better survival in ACE inhibitor-treated patients, but the differences were no longer significant (p = 0.14). These data, along with observations in adult patients with chronic cardiac failure, indicate that converting enzyme inhibitors have a beneficial effect on prolonging survival of infants and children with severe left ventricular dysfunction from dilated cardiomyopathy.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1991

Outcome of infants and children with dilated cardiomyopathy.

A review of 81 infants and children with dilated, poorly contracting left ventricles without associated structural abnormalities was undertaken to identify risk factors for poor outcome, which could be used in selecting candidates for cardiac transplantation. Significant atrial or ventricular dysrhythmias, or both, were detected on presentation or during follow-up in 24 patients. Arrhythmias were present in only 8 of 51 survivors (16%) but were detected in 16 of 30 patients (53%) who died (p less than 0.05). Patients dying suddenly were even more likely to have had documented dysrhythmias (8 of 11, p less than 0.05). Left ventricular shortening fraction was similar in survivors and nonsurvivors (14.9 +/- 1.0% vs 15.3 +/- 1.7%). Left ventricular end-diastolic pressure in 44 patients who had cardiac catheterization averaged 20.8 +/- 1.6 mm Hg. Left ventricular end-diastolic pressure was significantly higher in patients who died than in those who survived (29.5 +/- 2.2 vs 15.0 +/- 1.6 mm Hg, p less than 0.001). Analysis of actuarial survival revealed that mortality was highest during the first 6 months after presentation (19% mortality). Survival declined more gradually thereafter and was 70% at 2 years, 64% at 5 years and 52% after 11.5 years. Age at initial presentation did not have any significant impact on survival. However, left ventricular end-diastolic pressure greater than 25 torr was associated with a significantly increased mortality rate (p less than 0.05). Early cardiac transplantation should be considered in patients with markedly elevated left ventricular end-diastolic pressure or complex atrial or ventricular arrhythmias.

Actuarial Analysis↗
PubMed1989

Metabolic clearance rate (MCR) of dehydroepiandrosterone sulfate (DS), its metabolism to dehydroepiandrosterone, androstenedione, testosterone, and dihydrotestosterone, and the effect of increased plasma DS concentration on DS MCR in normal women.

The combined infusion of [3H]dehydroepiandrosterone sulfate [( 3H]DS) and [14C]estrone (E1) for 6 h in four normal women in the follicular phase of the cycle demonstrated values of 13.77 +/- 0.27 L/day (mean +/- SE) for the DS MCR (MCRDS) and 1343 +/- 206 L/day for MCRE1. The fraction of DS metabolized to dehydroepiandrosterone (D), [rho]DS-D, was 0.285 +/- 0.044, and the fraction of D arising from DS (delta D) was 0.318 +/- 0.096, determined using isotopic techniques. Raising the plasma DS concentration by 8.6 micrograms/mL (23 mumol/L) by infusing DS iv increased the MCRDS to 24.49 L/day in the first subject, and raising the plasma DS by 11.40 +/- 0.33 micrograms/mL (30.94 +/- 0.90 mumol/L) in the next three subjects raised the MCRDS to 35.7 +/- 1.3 L/day (P less than 0.01) without changing the MCRE1. The increase in MCRDS produced by increasing plasma DS makes it difficult to accurately measure the MCRDS in effect at the subject's endogenous plasma DS concentration by infusion of nonisotopic DS. Determination of the fractions of D, androstenedione (delta delta 4A), and testosterone (T) arising from DS using the increase in the plasma concentrations of these steroids produced by infusion of nonisotopic DS gave the following estimates: delta D = 0.262 +/- 0.042, delta delta 4A = 0.089 +/- 0.046, and delta T = 0.273 +/- 0.14.

Adult↗
PubMed1986

Usefulness of anticoagulant therapy in the prevention of embolic complications of atrial fibrillation.

The medical records of 254 patients with atrial fibrillation were reviewed to determine the incidence of embolic events in relation to type of cardiovascular disease, duration of atrial fibrillation, and use of anticoagulants. During a total follow-up of 833 patient-years in atrial fibrillation, there were 32 instances of systemic embolism: 21 involved the cerebral circulation and 11 were extracerebral. Thirty of these events occurred during 549 patient-years of follow-up without anticoagulation therapy (5.46 of 100 patient-years), while only two embolic events occurred during 284 patient-years on anticoagulants (0.7 of 100 patient-years). Thus, the incidence of embolism was eight times more frequent during the unanticoagulated period of observation in atrial fibrillation (p less than 0.002). The incidence of embolism during follow-up without anticoagulants was the same regardless of the presence or absence of mitral valve disease and regardless of whether atrial fibrillation was chronic or paroxysmal. The rate of serious hemorrhagic complications on anticoagulants was acceptably low (2.11 of 100 patient-years). We conclude that in this study population anticoagulant therapy reduced the risk of embolic complications of atrial fibrillation. The results also indicate that the use of anticoagulants should not be limited to patients with atrial fibrillation due to mitral valve disease.

Adult↗
PubMed1983

Comparative diagnostic performance of the Telemed computer ECG program.

One thousand consecutive ECG's from an ambulatory population of patients with suspected or proven cardiac disease were evaluated using two versions of the Telemed computerized ECG system. Only minor differences were found between the two programs. In version 6 vs. version 5, 87% vs. 90% of 287 normal ECG's were correctly classified and 93% vs. 96% of abnormal ECG's were correctly classified; the percent of acceptable diagnostic agreement was 86.2% and 87.4% respectively (NS). The sensitivity for arrhythmia detection, transmural inferior infarction and ST-T wave abnormalities was slightly greater in version 6. The increased sensitivity was not accompanied by decreased specificity. The sensitivity for left ventricular hypertrophy decreased from 95.2% to 91.4% in version 6 with a slight increase in specificity (95.2% to 97.0%). In conclusion, criteria changes in the most recent version of the Telemed program have not resulted in a major change in diagnostic performance. Arrhythmia detection is slightly but not significantly improved.

Adolescent↗
PubMed1983

Beneficial effect of intravenous diltiazem in the acute management of paroxysmal supraventricular tachyarrhythmias.

We tested the effectiveness and safety of i.v. diltiazem in the management of paroxysmal supraventricular tachyarrhythmias in 39 patients, 21 with organic heart disease and seven in heart failure. Fifteen patients presented with supraventricular tachycardia, 12 with atrial fibrillation and 12 with atrial flutter. End points were conversion to sinus rhythm or slowing of the ventricular rate to 100 beats/min or less. Diltiazem was given as an i.v. bolus of either 150 or 300 micrograms/kg over 2 minutes. A second injection was administered to patients who received the lower dose and failed to reach either end point within 30 minutes. The overall success rate was 82% (32 of 39 patients). Time to end point was 5 minutes or less in 20 patients. Conversion to sinus rhythm occurred in 13 of 15 patients (87%) with supraventricular tachycardia and in two of 12 patients with atrial fibrillation. Treatment side effects included a slow ventricular rate in one patient who had a sick sinus syndrome and hypotension in two patients that rapidly responded to fluid administration. We conclude that i.v. diltiazem is effective and well tolerated and advocate its use in the management of paroxysmal supraventricular tachyarrhythmias.

Adult↗
PubMed1981

[Value of the automated analysis of the electrocardiogram by the Telemed program (V version)].

A series of 1000 12 lead ECGs recorded in 1000 consecutive ambulatory patients were analysed by the Telemed (V Version) programme and its interpretation and the precision of the French translation were compared with the interpretation of two physicians using standard criteria. The computer identified 90% of the 285 ECGs coded as "normal" by the physicians, 69% of the 57 ECGs coded as "borderline" and 96% of the 658 ECGs coded as "abnormal". The computer interpretation was correct in 74% of cases and acceptable in 87,4% of cases. The computer classified 80% of the 240 arrhythmias correctly. Atrial fibrillation was detected in 91% of cases, and ventricular and supraventricular extrasystoles in 88% of cases. The recognition of other arrhythmias was not as good but the small number of cases did not allow statistical evaluation. The 148 cases of axis deviation and 98% of ventricular conduction defects were identified. The programme detected 84% of transmural infarcts, the sensitivity being greater for anterior or lateral than inferior infarctions. The majority of undiagnosed infarcts were "possibles" according to the criteria of the Minnesota Code. Of 536 ECGs with ST-T segment abnormalities, 81% were classified correctly; ST depression of less than 0.5 mm comprised the majority of false negatives. The sensitivity of the programme to left ventricular hypertrophy was excellent (95%) with a specificity of only 92,5% as the programme uses the Romhilt-Estes criteria which are more liberal than those of the Minnesota Code. The comparison of the sensitivity and specificity for the commonest ECG changes showed excellent all round diagnostic performance of the Telemed programme. In conclusion, despite the large number of abnormal ECGs, the level of computer-physician concordance was high. The French translation of the V Version of the Telemed programme is therefore suitable for clinical use Nevertheless, the computer interpretation should still be checked by a physician.

Computers↗
PubMed1980

MB creatine kinase and the evaluation of myocardial injury following aortocoronary bypass operation.

Myocardial injury was studied in 104 patients undergoing coronary artery grafting without cold chemical cardioplegia using the quantity of the isoenzyme MB of the creatine kinase liberated as an indicator. This method of evaluation, which is said to permit comparison of different techniques of myocardial protection, allowed us to consider the relative importance of several factors believed to have an influence on intraoperative myocardial injury. Indices of significance were duration of symptoms before operation, presence of chronic arterial hypertension, and the type of antiangina treatment employed. Other operative factors included severity of the arterial lesions, number of anastomoses performed, and duration of extracorporeal circulation and of aortic cross-clamping.

Angina Pectoris↗
PubMed1978

Bioavailability of three commercial sustained-release tablets of quinidine in maintenance therapy.

The bioavailability of three quinidine formulations was estimated during a dosing interval at steady state following their administration in 12 selected patients in accordance with a Latin-square 3 x 3. Each subject received the three dosage forms as two tablets every 12 hr for 6 days. Blood and urine samples were taken on the 7th day during the regular 12-hr dosing interval. Unchanged quinidine was determined by a reported spectrofluorometric procedure. The total fluorescence of plasma quinidine and metabolites also was monitored. The data obtained indicate that one dosage form gave a high peak level followed by a fall in the concentration. The two other forms presented a relatively lower peak followed by a plateau and then a decline. The differences between the dose-corrected values of Cp,max were statistically significant. Secondary effects were observed particularly with one dosage form and could be related to the high Cp,max value and/or the high percentage of quinidine liberated rapidly in the GI tract. Blood and urinary data indicated an equivalent degree of absorption. The dissolution behavior of the formulations and their absorption data suggest that there is a correlation between the quantity dissolved at 30 min and Cp,max.

Adult↗
PubMed1978

Long term follow-up of aneurysmectomy for recurrent ventricular tachycardia or fibrillation.

The success of aneurysmectomy in abolishing recurrent ventricular tachycardia or ventricular fibrillation has not been clearly defined. Ten patients who underwent aneurysm resection to control ventricular arrhythmias were studied before and an average of 19 (4 to 42) months following operation. All patients had moderate to large aneurysms and four had asynergy in adjacent segments. Of four patients with significant stenosis in vessels not supplying the aneurysm, three had aortocoronary bypass grafts in addition to their resection. Ambulatory Holter monitoring and a graded exercise test were performed in all patients postoperatively. There was no operative mortality. Two patients who did not have associated revascularization procedures died suddenly 1.5 and 7 months postoperatively. Of the eight survivors, despite clinical improvement, the Holter ECG revealed runs of ventricular tachycardia in three patients and frequent multifocal ventricular extrasystoles in the other five patients. No correlation was found between recurrence of the ventricular arrhythmias and aneurysm size, contraction pattern of other myocardial segments, extent of coronary disease, or the presence of congestive heart failure. In conclusion, aneurysmectomy does not abolish ventricular tachyarrhythmias and probably should be reserved for patients who remain symptomatic despite an adequate medical trial. The persistence of complex arrhythmias following operation warrants a close follow-up in these patients.

Adult↗