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Biomedical subjects

J Caron

Publications and source records attributed to J Caron.

At least 37 records · Page 2Linked to original sources
PubMed1998

Components of social support and quality of life in severely mentally ill, low income individuals and a general population group.

Satisfaction with social support and quality of life (QOL) were assessed for 60 psychiatric patients, 79 welfare recipients and 266 people of the general population using the Social Provisions Scale (SPS) and the Satisfaction with Life Domains Scale (SLDS). Psychiatric patients reported less satisfaction than the general population on all components of social support. They have a comparable level of satisfaction with welfare recipients on most of the components, with the exception of emotional integration and opportunity for nurturance. However, patients satisfaction with QOL was quite similar to the general population, although higher than welfare recipients on some dimensions. Their lower satisfaction with the personal-intimate dimension suggest deficiencies in social support. All components of social support were consistently related to QOL in the general population. Attachment and reassurance of worth was significant for psychiatric patients but only attachment was related to QOL for the welfare recipients group. The pairing of SPS and SLDS scales seem to be good instruments for discriminating the majority of psychiatric patients.

Adult↗
PubMed1998

Risk and penetrance of primary hyperparathyroidism in multiple endocrine neoplasia type 2A families with mutations at codon 634 of the RET proto-oncogene. Groupe D'etude des Tumeurs à Calcitonine.

Germline mutations of the RET proto-oncogene are responsible for multiple endocrine neoplasia type 2, including multiple endocrine type 2A (MEN 2A), type 2B (MEN 2B), and familial medullary thyroid carcinoma. The relationship between specific mutations and syndromic features has been established. In particular, the risk for pheochromocytoma and hyperparathyroidism (HPT) in MEN 2A patients is clearly associated with the presence of the RET mutation at a specific position, i.e. at codon 634. Also, a correlation between a specific mutation, C634R, and the development of HPT has been suggested but is still controversial. To further investigate the relationship between specific mutations of codon 634 and the development of HPT, we studied a population of 188 individuals, carrying mutations at codon 634, namely C634R (65 patients belonging to 10 families), C634Y (80 patients belonging to 11 families), or the less frequent codon 634 mutations [i.e. C634S, C634F, C634G, or C634W (43 patients belonging to 9 families)]. In this series of patients, we defined an overall HPT prevalence of 19.1% and found that this prevalence did not vary significantly, with respect to the nature of the mutation. However, irrespective of the particular mutation, the prevalence of HPT showed a high interfamilial variability. The statistical model that best fitted with the observed data was in favor of the heterogeneity of the risk for HPT, with 40% of the families showing an HPT risk of 34% and 60% of the families showing an HPT risk of 9%. In addition, our study clearly demonstrated that HPT could be an early component of the disease and provided the first estimate of age-specific and mutation-specific HPT penetrance in individuals with mutations of codon 634 of the RET proto-oncogene.

Adult↗
PubMed1998

[Von Hippel-Lindau disease: recent genetic progress and patient management. Francophone Study Group of von Hippel-Lindau Disease (GEFVH)].

Von Hippel-Lindau (VHL) disease is an autosomal dominant disorder, predisposing to the development of central nervous system (CNS) and retinal hemangioblastomas, endolymphatic sac tumors, renal cell carcinoma and/or renal cysts, pheochromocytomas, pancreatic cysts and/or tumors. Incidence of the disease is 1/36,000. CNS hemangioblastomas and renal cell carcinoma are the main causes of death. The VHL gene, located on 3p25-26, is a tumor-suppressor gene which plays a major role in regulation of VEGF expression. Germline mutations of the VHL gene are identified in about 70-99% of the patients. Mutations associated with VHL type 2 (with pheochromocytoma) are mainly missense mutations with hot-spot at codon 167. Somatic mutations of the VHL gene are found in both sporadic central nervous system hemangioblastomas and sporadic renal cell carcinoma. For endocrinologists search for VHL disease (as for MEN) should be imperative in presence of a patient with pheochromocytoma and neuroendocrine pancreatic tumor.

Carcinoma, Renal Cell↗
PubMed1998

[Electrophysiologic effects and arrhythmogenic potential of diphemanil methylsulfate on rabbit purkinje fibers. Correlations with clinical observations of QT prolongation in pediatrics].

Serious undesirable cardiac side effects have been reported with treatment with diphemanil methylsulfate (Prantal) in premature babies or neonates. To understand the origin of this problem, the authors undertook an electrophysiological study of the effects of this product in vitro on rabbit Purkinje fibres. In three separate series (N = 5 to N = 8), the effects of increasing concentrations (0.1 microM-30 microM) of diphemanil methylsulfate, different frequencies of stimulation (0.2 Hz, 1 Hz, 2 Hz) and duration of exposition (60 min followed by 120 min washout) were observed on the properties of the action potential. The results show a clearcut antiarrhythmic Class III type action characterised by a concentration-dependent prolongation of the action potential duration with an inverse frequency dependency without significant changes of the other parameters. During stimulation at 0.2 Hz, early post-depolarizations and induced activity were observed in 3/8 of the fibres exposed to 10 microM and 8/8 fibres exposed to 30 microM. The effect did not attain a steady state after 60 min of exposition. It was not reversed by 120 min of washout of the preparation. These results were compatible with the reported cardiac arrhythmic effects of prolongation of the QT interval and torsades de pointe.

Action Potentials↗
PubMed1997

Effect of ramipril on heart rate variability in digitalis-treated patients with chronic heart failure.

The aim of this study was to evaluate the effect of an angiotensin-converting enzyme (ACE) inhibitor, ramipril, on heart rate variability in patients with heart failure simultaneously treated with digitalis. This study was a multicentric, randomized, double-blind, placebo-controlled study including 50 patients with chronic heart failure (CHF). All patients were in NYHA functional class II and III. The etiology of CHF was mainly idiopathic dilated cardiomyopathy and ischemic heart disease. After a 4-week placebo run-in period with digoxin and diuretics, patients were randomized to receive additional ramipril or placebo. To assess heart rate variability (HRV) and arrhythmias, 24-hour ECGs were recorded at the end of the placebo run-in period, 8 and 24 weeks after randomization. Spectral analysis of HRV was performed during one diurnal and one nocturnal 5-minute time period. No statistically significant differences in HRV within low-, high-, and total-frequency bands were induced by ramipril in either the diurnal or nocturnal periods, both at 8 and 24 weeks after randomization. Ramipril produced a significant decrease in nonsustained ventricular tachycardia at 24 weeks of treatment (p = 0.01). These results run against previous observations showing an increase in parasympathetic tone with ACE inhibitors in heart failure. The present study thus suggests that the effects of ACE inhibitors in CHF are variable and depend on the patient and concomitant treatment that might influence HRV such as digoxin treatment.

Adult↗
PubMed1997

Adverse effects of class I antiarrhythmic drugs.

Class I antiarrhythmic drugs are characterised by their ability to block the fast inward sodium current in cardiac muscle tissue. However, at the same time, they can be responsible for various effects involving other organs and systems. Although some of these effects can be helpful in specific situations, most of them, such as their pro-arrhythmic propensity, are deleterious. Some of the adverse effects of class I antiarrhythmic drugs are directly linked to sodium-channel blockade (conduction disorders haemodynamic perturbations, and digestive and neurological effects), while others are linked to other specific pharmacological properties (e.g. atropinic, or alpha- or beta-adrenergic blockade) or to nonspecific properties (idiosyncratic hypersensitivity, and haematological, dermatological or hepatic reactions). Other adverse effects are associated with complex interactions between class I antiarrhythmics and individual predisposing factors, trigger mechanisms and physiological factors (including concomitant drug treatment). These numerous variations and interactions within a specific environment and underlying disorder might be of pharmacological or/and pharmacokinetic origin, making analysis of the true liability of the class I drugs very difficult when adverse effects occur.

Anesthesia, Local↗
PubMed1997

Quality of life and social integration of severely mentally ill patients: a longitudinal study.

The quality of life concept serves to measure functional changes and program outcome. Patients with schizophrenia have an improved prognosis. Is quality of life improving over time, and if so, over what period? These questions were addressed in a longitudinal study where subjective quality of life (SQOL) was rated by severely mentally ill patients living in the community and using support services located in an outlying area of Quebec. The Satisfaction for Life Domains Scale (SLDS) (Baker and Intagliata 1982) measuring SQOL as a whole and in specific domains (for example, housing, finances, social relationships) was repeated over a period of 7 y. Results show that SQOL ratings received the same scores after 7 y. Functional status was decreased, while social integration improved and more services were used. The results could be due to sample characteristics or to the ambiguity of the SQOL construct. In our opinion, extensive community-based support services may have played a key role in the maintenance of patient's quality of life.

Adult↗
PubMed1997

[Validation of Satisfaction with Life Domains Scale in Quebec].

This article presents the results of the Quebec validation of the Satisfaction With Life Domains Scale: This scale was developed in the United States for the general population and adapted for severely mentally ill individuals. Two hundred and sixty six individuals from the general population and 245 severely mentally ill persons participated in this study. Factor analysis allowed the identification of four sub-scales for the clinical population and five for the general population. The scale (alpha = 0.90) and the sub-scales (alpha between 0.60 et 0.84) show excellent internal consistencies and the test-retest reliability was good (r = 0.73). Moreover, analysis of the variance and the discriminant analysis allow to acknowledge that the sub-scales have a high discriminating power; they allow to distinguish the general population from welfare recipient and people suffering from psychosis. The overall results suggest that l'Echelle de satisfaction des domaines de vie have good psychometric properties and can be considered as a valid instrument for assessing subjective quality of life in descriptive or evaluative studies.

Analysis of Variance↗
PubMed1996

[The scale of social provisions: their validation in Quebec].

This article presents the results of the Quebec validation of the Social Provisions Scale (Cutrona et Russell, 1989). L'échelle de provision sociales was administered to 790 people on the course of two studies. The first one included 387 university students of first level and the second was realized with 266 people from the general population, 79 welfare recipients and 58 persons with a diagnosis related to psychosis. The results show that the scale presents a good internal coherence and a satisfying temporal stability, thus assuring the fidelity of the instrument. The factorial analyses have not reproduced exactly the same profile as the original instrument, however the moderate correlations between the different social provisions sustain the validity of the multidimensional construct of social support. Moreover, analyses of the variance and the discriminating analysis allow to acknowledge that the sub-scales have a high discriminating power; they allow to distinguish the general population from welfare recipients and people suffering from psychosis. Finally, norms are presented for the general population.

Humans↗
PubMed1995

[Suicide in Abitibi-Témiscamingue: epidemiologic studies for 1986-1991].

A permanent register on suicide cases was created and has produced a quantitative description of suicide in Abitibi-Temiscamingue over the period 1986-1991. This study reviews 218 suicide cases reported by the Coroner's Office of Quebec. A content analysis grid was applied on the Coroner's files and has facilitated the study of 87 variables potentially related to suicide. The results present the evolution of the suicide rates in this region in relation to those of other parts of Quebec, and the differences between parts of the region. Many variables were related to suicide (age, gender, urban setting, methods, suicide sites, seasons, etc.). A review of recent literature on suicide throughout the world indicates that patterns of suicide in Abitibi-Temiscamingue follow trends in North America with certain differences.

Adolescent↗
PubMed1994

Regulation of rns, a positive regulatory factor for pili of enterotoxigenic Escherichia coli.

Attachment of enterotoxigenic Escherichia coli to the human gut is considered an important early step in infection that leads to diarrhea. This attachment is mediated by pili, which belong to a limited number of serologically distinguishable types. Many of these pili require the product of rns, or a closely related gene, for their expression. We have located the major promoter for rns and found that although its sequence diverges significantly from a sigma-70 promoter consensus sequence, it is very strong. Transcription of rns is negatively regulated both at a region upstream of this promoter and at a region internal to the rns open reading frame. In addition, rns positively regulates its own transcription, probably by counteracting these two negative effects.

Base Sequence↗
PubMed1993

Acute electrophysiological effects of intravenous milnacipran, a new antidepressant agent.

Milnacipran is a new antidepressant agent selected from a series of cycloproprane derivatives. The aim of this study was to investigate the acute electrophysiological effects and the tolerance of intravenous administration of this drug in 10 patients without any abnormality as shown in an electrophysiological study done for various complaints. Milnacipran was given over a 30-min period at doses of 0.2 mg/kg (2 patients), 0.4 mg/kg (2 patients) and 0.8 mg/kg (6 patients). The most significant alterations observed in this study were increases in heart rate (average of maximal increase: +19.5% at 50 min, P = 0.06) and systolic blood pressure (average of maximal increase: +21.5% at 10 min, P < 0.005), and decreases in the functional refractory period of the atrium (-3%, P < 0.05), the atrioventricular node (-9%, P < 0.005) and the effective refractory period of the right ventricle (-10.8%, P < 0.05) at 50 min. The sinus node function was improved in nine patients but depressed in one patient with previous slight baseline sinus node alterations. Milnacipran being devoid of both anticholinergic and monoamine oxidase inhibition activities, these alterations could be related to inhibition of noradrenaline uptake leading to an increase of adrenergic activities. No other ECG or electrophysiological parameters were significantly altered. Five of the 10 patients reported transient nausea, four of them for the highest dosage (0.8 mg/kg) and at the moment of peak of milnacipran plasma level. In conclusion, electrophysiological effects of intravenous milnacipran are negligible. These findings differ from those, well described in the literature, for imipramine-like antidepressant agents.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗