PubMed Health⌕ Search

Biomedical subjects

L Lévesque

Publications and source records attributed to L Lévesque.

At least 37 records · Page 2Linked to original sources
PubMed1995

Informal and formal support for caregivers of a demented relative: do gender and kinship make a difference?

Gender and kinship were examined with regard to caregivers' use of informal and formal support and to two models of support (substitution or supplementation). Three groups of caregivers of a demented relative living at home--husbands, wives, and adult daughters--were compared on measures of both informal and formal support. The gender hypothesis deals with the similarities among caregivers of the same gender with respect to support. The kinship hypothesis refers to the similarities among caregivers having the same kinship with the carereceiver. The gender hypothesis was confirmed for informal informational support while the kinship hypothesis was supported for informal conflictual support. For most of the comparisons, the three groups of caregivers shared more similarities than differences. The interchangeability between informal and formal support seems to fall under the perspective of kinship because the daughter group is the only one where a model of supplementation was observed.

Adult↗
PubMed1994

Cohabitation of alert residents with cognitively impaired peers in nursing homes: the nursing staff's point of view.

The nursing staff's point of view has rarely been examined in regard to the difficulties of cohabitation of alert residents with those who are cognitively impaired. The aims of this study were to assess the nursing staff's preference for mixed or segregated care settings and to identify the factors related to this preference. A systematic sample of 349 nursing staff members working in mixed care settings in 19 nursing homes in Montreal (Canada) completed a questionnaire. There were as many staff members who favored mixed care settings as there were those who preferred segregated settings. A stepwise regression analysis revealed that 46% of the variance is explained by the model, and factors related to staff concerns about residents accounted for 42% of that variance. Notably, staff members who gave a lower rating to the disadvantages for lucid residents living on mixed care units or those who reported more benefits for nonlucid residents living on mixed care units were more in favor of cohabitation. Factors related to staff members' personal concerns explain 3% of the variance. In-service educational strategies are discussed.

Adult↗
PubMed1994

Alzheimer A beta amyloid forms an inhibitory neuronal substrate.

Alzheimer's disease (AD) is identified by the accumulation of amyloid plaques, neurofibrillary degeneration, and the accompanying neuronal loss. AD amyloid assembles into compact fibrous deposits from the amyloid beta (A beta) protein, which is a proteolytic fragment of the membrane-associated amyloid precursor protein. To examine the effects of amyloid on neuron growth, a hybrid mouse motoneuron cell line (NSC34) exhibiting spontaneous process formation was exposed to artificial "plaques" created from aggregated synthetic A beta peptides. These correspond to full-length A beta residues 1-40 (A beta 1-40), an internal beta-sheet region comprising residues 11-28 (A beta 11-28), and a proposed toxic fragment comprising residues 25-35 (A beta 25-35). Fibers were immobilized onto culture dishes, and addition of cells to these in vitro plaques revealed that A beta was not a permissive substrate for cell adhesion. Neurites in close contact with these deposits displayed abnormal swelling and a tendency to avoid contact with the A beta fibers. In contrast, A beta did not affect the adhesion or growth of rat astrocytes, implicating a specific A beta-neuron relationship. The inhibitory effects were also unique to A beta as no response was observed to deposits of pancreatic islet amyloid polypeptide fibers. Considering the importance of cell adhesion in neurite elongation and axonal guidance, the antiadhesive properties of A beta amyloid plaques found in vivo may contribute to the neuronal loss responsible for the clinical manifestations of AD.

Alzheimer Disease↗
PubMed1994

[The development of a research program based on a conceptual model for the discipline of nursing].

The purpose of this article was to illustrate the development of a team's research program based on a conceptual model for the nursing discipline: Roy's Adaptation Model. The ongoing research program includes studies of psychosocial factors, theoretically known for their potential for explaining health. Four groups of people are the focus of these studies: aged spouses in the community, family caregivers of ill elderly people, family caregivers of mentally ill people, and nurses as professional caregivers for elderly people in institutions. The studies are articulated using the three-level structure proposed by Fawcett & Downs (1986) and Fawcett (1991): conceptual-theoretical-empirical. This research program aims to renew understanding of the person's adaptation processes to various environmental stimuli, adaptive responses that influence health, and nursing interventions that promote health (i.e., biopsychosocial integrity). In order to specify the research variables and relations to be studied between these variables in the first phase of the program, each research project is also guided by a middle-range theory compatible with Roy's Adaptation Model. Elaborated within related disciplines, these theories are variations of the Stress and Coping theory of Lazarus & Folkman (1984). The results of these studies will be compared and articulated in a model that integrates the patterns of relations between the variables. The resulting empirical model together with Roy's conceptual model will be used to guide the development of nursing interventions intended to promote adaptive responses and biopsychosocial integrity. The second phase of the research program includes the implementation and evaluation of nursing strategies that promote adaptation among the four groups of people. This research program is a nursing contribution to certain social issues recognized as priorities by the governments of Canada and Québec. This article is an illustration of one of the various ways of developing nursing knowledge.

Adaptation, Psychological↗
PubMed1993

Caregiving tasks as predictors of mental health of wife caregivers of men with chronic obstructive pulmonary disease.

The type, number, and amount of disturbance generated by caregiving tasks as well as the adequacy of informal social support were examined as predictors of the mental health of 89 wife caregivers of men with chronic obstructive pulmonary disease (COPD). The number of supervision tasks performed was predictive of all the mental health outcomes except one. When disturbance level was examined, giving emotional support in difficult situations was the task category that predicted five of the eight outcomes. Support variables accounted for small amounts of variance of most outcomes. However, caregivers who received respite support when they needed it were actually three times more likely to take psychotropic drugs than those not receiving support.

Aged↗
PubMed1993

Biochemistry of Alzheimer's disease amyloid plaques.

One of the principal identifying features of Alzheimer's disease (AD) is the extracellular deposition of fibrous protein aggregates in the form of amyloid plaques. The major component of these deposits is the amyloid beta (A beta) protein that is a proteolytic fragment of the integral membrane amyloid precursor protein (APP). Understanding the pathways responsible for A beta formation and the mechanism by which it accumulates within the brain could provide key answers to AD pathogenesis. This review will explore the biochemistry of A beta and its precursor, the possible causal relationship between amyloid and AD-associated neuronal death, the role of additional cellular elements in amyloid formation, and the potential application of these components in clinical diagnosis.

Alzheimer Disease↗
PubMed1993

Why alert residents are more or less willing to cohabit with cognitively impaired peers: an exploratory model.

This study tested a model of the willingness of alert residents to cohabit with cognitively impaired peers in nursing homes. A systematic sample of 435 alert residents living on mixed care units selected in 19 nursing homes were interviewed. Four factors were of particular influence on the willingness to cohabit: alert residents' negative emotional reactions to living with the cognitively impaired, their knowledge of confusion, disturbance generated by dysfunctional behaviors, and benefits of cohabitation for the cognitively impaired as perceived by alert residents.

Aged↗
PubMed1993

[The frequent screams].

Functional analysis is a research process that links problem behavior, its surrounding elements and the resulting consequences. The goal of this study was to decrease repetitive shouting of an elderly patient diagnosed with Alzheimer-like dementia. The analysis provided the following data: BEHAVIORS: Repetitive shouting by the patient lasting 80-115 seconds per 30 minutes during specific times of the day--accompanied by licking of the lips to moisten them. Environmental factors: Constant loud noise in the patient's room; the use of loud voices by staff and visitors; familiar objects out of the patient's reach. Individual factors: Diagnosis of the patient's blindness and auditory hypersensitivity; side-effects of psychotropic medications; a lack of social activities; inactivity because of the patient being bedridden 22 hours per day and the use of restraints when positioned in a chair. SURROUNDING ELEMENTS: The patients was isolated in a private room; psychotropic medication was increased; staff and other patients were less disrupted and the number of visitors to the patient was decreased. CONSEQUENCES: The above data enabled the formulation of four hypotheses (with specific interventions for each) that assisted staff in planning the patient's care for a 10-day period; a reduction of anxiety; a reduction in discomfort; sensory hypostimulation; verbal hypostimulation. Following the application of these interventions for a 10-day period, a second set of data was gathered and the results showed a decrease in shouting by 40 per cent in the morning and 51 per cent in the afternoon.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1992

A sensorimotor basis for motor learning: evidence indicating specificity of practice.

Our previous work (Proteau, Marteniuk, Girouard, & Dugas, 1987) was concerned with determining whether with relatively extensive practice on a movement aiming task, as the skill theoretically starts becoming open-loop, there would be evidence for a decreasing emphasis on visual feedback for motor control. We eliminated vision of the moving limb after moderate and extensive practice and found that the movement became more dependent on this feedback with greater amounts of practice. In the present study, we wished to test the hypothesis, developed from our previous work, that at the base of movement learning is a sensorimotor representation that consists of integrated information from central processes and sensory feedback derived from previous experiences on the movement task. A strong test of this hypothesis would be the prediction that for an aiming task, the addition of vision, after moderate and relatively extensive practice without vision, would lead to an increasingly large movement decrement, relative to appropriate controls. We found good support for this prediction. From these and our previous results, and the idea of the sensorimotor representation underlying learning, we develop the idea that learning is specific to the conditions that prevail during skill acquisition. This has implications for the ideas of the generalized motor program and schema theory.

Feedback↗
PubMed1992

Maintenance of long-term secretory function by microencapsulated islets of Langerhans.

Continuous responses of insulin and glucagon to physiological challenges are essential for the maintenance of normoglycemia and for avoiding subsequent health complications. Transplantation of microencapsulated islets of Langerhans is a promising solution to obtain such a physiological system in diabetic patients. The integrity of the islets' secretory mechanism after encapsulation was studied using rat islets. Islets were isolated by collagenase digestion after which half of the islets were encapsulated with an alginate-poly-L-lysine-alginate membrane. The islets were then challenged for 24 h with glucose (0, 2.7, 5.5, or 20 mM) alone or with 0.1 mM 3-isobutyl-1-methyl-xanthine or 0.1 microM phorbol 12-myristate 13-acetate (PMA), protein kinase A and C pathway stimulators, respectively. The bathing media and cellular contents were radioimmunoassayed for insulin and glucagon. Results obtained using a three-way analysis of variance for microencapsulated and free islets demonstrated that high glucose (P less than 0.05), 3-isobutyl-1-methyl-xanthine (P less than 0.05), and PMA (P less than 0.01) increased insulin secretion, and that glucagon secretion was decreased by high glucose (P less than 0.01) but increased by PMA (P less than 0.05). Free islets secreted more insulin than those which were microencapsulated under all conditions (P less than 0.01). This appeared to be due to the encapsulation process itself, however, as islets which had been 'freed' from the capsules also exhibited a reduced capacity for insulin secretion (P less than 0.05). Analysis of the hormone content of islets after microencapsulation demonstrated reduced insulin levels (P less than 0.01), thus, accounting for the reduction in insulin secretion. As the responses of microencapsulated islets to physiological regulation by glucose and protein kinases A and C were qualitatively identical to those of free islets, transplantation of microencapsulated islets into diabetic patients could mimic the physiological responses of the normal pancreas.

1-Methyl-3-isobutylxanthine↗
PubMed1992

[Cohabitation of lucid and non-lucid residents].

The primary goal of this study was to confirm the appropriateness of an experimental model that studied the emotions of a rational client toward living with cognitively impaired clients. The second goal was to identify factors linking the feelings of health caregivers toward the cohabitation or segregation of rational and cognitively impaired couples. The research took place in 19 Montreal senior citizen homes with 75 beds or more. The senior citizen homes, the rational clients and the health caregivers were selected using specific criteria and systematic sample selection. Individual interviews with 435 rational clients living in cohabitation units were undertaken. In addition, 349 health caregivers (nurses, practical nurses and attendants) responded to a questionnaire relating to the cohabitation of these couples. It was found that the rational clients adjusted well to the model. Four variables reflecting the emotions of 33 per cent of the rational partners include: The frequency of uncomfortable feelings related to living with the cognitively impaired; their knowledge level about cognitive impairment; their distress level relating to the confused/irrational behavior of the cognitively impaired; and their perception of the advantages of living with the cognitively impaired. The rational clients who had the least understanding of cognitive impairment identified that they were more upset by the confused client's behavior. They demonstrated uncomfortable feelings toward living with confused/irrational clients more frequently, and perceived less advantages relating to cohabitating with these clients. Consequently, the rational clients were less amenable to cohabitation. The percentage of cognitively impaired clients living on the same floor was not identified as a variable.(ABSTRACT TRUNCATED AT 250 WORDS)

Attitude to Health↗
PubMed1989

Decision making in sport: the effect of stimulus-response probability on the performance of a coincidence-anticipation task.

The purpose of the present study was to evaluate the quality of a motor response for different levels of expectancy and time constraint, in a two-choice coincidence-anticipation task. The probability of each of the two events likely to be presented were varied across different levels as well as the speed of the stimulus to be intercepted. The results indicated that neither the choice reaction time (CRT) and movement time, nor the performance of coincidence-anticipation were affected by the probability of the stimulus for the low and moderate stimulus speeds. However, when the stimulus traveled at a high speed a trade-off took place. The CRT decreased as the probability of the event increased, whilst the proportion of response initiation errors increased for the low probability events. This trade-off resulted in a better coincidence-anticipation as the probability of the event increased. The results obtained in the present experiment are clearly different from those obtained in a classic CRT-deadline paradigm, in that the trade-off observed between CRT and response initiation errors was far less pronounced in the coincidence-anticipation task. This difference was attributed to the higher negative consequences associated with a response initiation error in a coincidence-anticipation task. It is thus concluded that the tasks used to study the nature of the decision processes taking place in sports and sports-like situations must have some ecological validity to be of some help for the practitioner.

Adult↗
PubMed1986

[Decision strategy: effect of the proportion of total response time taken by choice reaction time].

Results from two series of studies on decision strategies suggested that subjects appeared to chose between two response modes. Subjects could use a decision strategy based either on anticipatory responses or on reaction responses. It appeared that certain characteristics specific to the task could be responsible for the discrepancy in the response mode. The aim of the present study was to ascertain whether the choice of a decision strategy could be dictated by the proportion of total response time taken up by the choice reaction time (TRC). For instance, if the TRC takes up a large proportion of the total time, reducing it in view of an anticipatory response could considerably reduce the total time. The advantage to be gained from an anticipatory response could thus be considered sufficient to warrant adoption of a decision strategy based on anticipation. On the contrary, when TRC takes up only a small portion of total time, a decision strategy based upon reactions is preferred since the cost related to an error in response would largely exceed the advantage related to anticipation. Results from the two series of experiments presented in this paper support the importance of this variable. More specifically, results revealed that the error that an individual allows himself to make depends upon the proportion of total time that is devoted to choice reaction time. An extension of the model presented by Proteau et al. is proposed in order to account for the present observations.

Choice Behavior↗
PubMed1984

Evaluation of a presurgical group program given at two different times.

This study was designed to test the outcomes of a preoperative teaching program for cholecystectomy patients and to determine the appropriate time to offer the program. The hypotheses were: (a) Patients in a preadmission program will recover better than those in a program given the eve of surgery, and (b) patients in the control group will have a poorer recovery than those in the two experimental groups. The outcomes measured were state-anxiety, ventilatory function, well-being, pain, functional ability, analgesics, and length of hospitalization. There were no significant differences between the three groups except in state-anxiety the eve of surgery which was higher in the control than in the two experimental groups. State-anxiety the eve of surgery and trait-anxiety were the most important variables affecting outcomes. There was a positive and significant linear relationship between pre- and postoperative state-anxiety.

Adolescent↗
PubMedDate not supplied

Reactions of the institutionalized elderly upon learning of the death of a peer.

An exploratory study of 25 institutionalized elderly people who witnessed the death of a co-resident is reported. Two topics are examined: thoughts and feelings of the survivors about their own death and the climate surrounding the death of a peer. Data obtained through a semistructured interview reveal that learning of a peer's death leads more than one third of the elderly residents to consider their own death. Witnessing a peer's death seems to have little positive or negative influence. On one hand, 84% of them state that they want to be informed of the impending death of a well-known peer; on the other hand, 80% reported that the staff does not say when a peer is dying. Half of the respondents perceive the staff as indifferent to the death of an elderly person.

Aged↗
PubMedDate not supplied

Aerobic exercise and the placebo effect: a controlled study.

An experiment was conducted with 48 healthy young adults engaged in a supervised 10-week exercise program to determine whether a placebo effect is involved within the exercise-psychological enhancement connection. Based on an expectancy modification procedure, one-half of the subjects were led to believe that their program was specifically designed to improve psychological well-being (experimental condition) whereas no such intervention was made with the second half (control condition). Expectations for psychological benefits and aerobic capacity (VO2max) were measured before and after completion of the program. Self-esteem, as the indicator of psychological well-being, was measured on four specific occasions: at the beginning, after the fourth and seventh weeks, and upon completion of the training program. The results showed similar significant increases in fitness levels in both conditions. Moreover, self-esteem was significantly improved over time in the experimental but not in the control condition. These findings provide evidence to support the notion that exercise may enhance psychological well-being via a strong placebo effect. Implications of the results with regard to exercise prescription are discussed.

Adult↗
PubMedDate not supplied

The ecological approach in tobacco-control practice: health promotion practitioner characteristics related to using the ecological approach.

PURPOSE: To identify cognitive factors and personal characteristics related to the integration of the ecological approach in the everyday practice of health promotion practitioners. DESIGN: Sociodemographic, cognitive, and behavior data were collected using a cross-sectional mail survey. SETTING: Information was collected from regional public health organizations (n = 129) in the 10 Canadian provinces. SUBJECTS: Health promotion practitioners involved in tobacco-control programming for youth (n = 524) comprised of 81% women with a mean age of 39 years. MEASURES: Attempts to integrate ecological strategies (i.e., interpersonal, organizational, and policy change) into tobacco-control practice were based on three self-report items. Six scales assessed knowledge, values, and normative beliefs about the ecological approach as well as perceived need for, effectiveness of, and competency regarding using the ecological approach. RESULTS: The survey response rate was 80%. Stepwise discriminant analyses revealed four predictors (p < .001) contributing to the function solution concerning practitioner attempts to target the interpersonal environment: perceived competency, training discipline, years doing health promotion, and gender. Three predictors (p < .001) contributed to each of the function solutions concerning practitioner attempts to target the organizational environment (perceived competency, perceived effectiveness, and normative beliefs) and practitioner attempts at policy change (perceived competency, knowledge, and normative beliefs). CONCLUSIONS: Tobacco-control practitioners who perceive themselves as having the skills to develop and/or implement interventions targeting a person's environment are more likely to target the environment for change.

Adult↗