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Biomedical subjects

J Chevrier

Publications and source records attributed to J Chevrier.

At least 19 recordsLinked to original sources
PubMed2002

Increase in plasma pollutant levels in response to weight loss is associated with the reduction of fasting insulin levels in men but not in women.

Environmental pollutants can act as endocrine modulators. In this study, we examined whether weight loss-induced changes in plasma organochlorine compounds (OC) were associated with those in plasma insulin levels. Fasting insulin and the area under the curve (AUC) of insulin after a 75-g oral glucose load, plasma levels of 1 commercial polychlorinated biphenyl (PCB) mixture (Aroclor 1260), 1 PCB congener (PCB 153), and 3 pesticides (2,2'-bis(4-chlorophenyl)-1,1-dichloroethylene (p,p'-DDE), beta-hexachlorocyclohexane (beta-HCH), and hexachlorobenzene (HCB)) were measured before and after a 15-week weight loss program induced by a caloric restriction in a sample of obese men and women. Both genders showed a similar reduction in body weight (approximately 11 kg) in response to treatment, although men lost significantly more fat mass than women (mean +/- SD 9.4 +/- 4.1 v 5.9 +/- 5 kg, respectively, P <.05). Fasting insulin and AUC of insulin significantly decreased in men and women after the treatment. In response to weight loss, a significant increase in OC was observed in both genders, and this effect was more pronounced in men. The greater the increase in plasma OC levels, the greater the reduction in fasting insulin was in response to weight loss in men (-.49 < r < -.59, P <.05), but not in women (-.22 < r <.01, not significant [NS]). In both genders, no relationship was observed between changes in plasma OC levels and changes in AUC of insulin (-.41 < r < -.08, NS). In men, relationships between changes in plasma HCB, Aroclor 1260, and PCB-153 concentrations and those in fasting insulin levels in response to weight loss remained significantly correlated after correction for fat mass loss (-.46 < partial r < -.51, P values ranging from.05 to.07). These results suggest that weight loss-induced increase in plasma pollutant levels tends to be independently associated with the reduction of fasting insulin levels in men, but not in women. Further studies are needed to verify whether these findings are causally related.

Adipose Tissue↗
PubMed2001

Increase in plasma pollutant levels in response to weight loss in humans is related to in vitro subcutaneous adipocyte basal lipolysis.

OBJECTIVE: To examine whether weight loss-induced changes in in vitro basal lipolysis of subcutaneous abdominal and femoral fat cells were related to those in plasma organochlorine levels. DESIGN: A 15 week weight loss program induced by a moderate caloric restriction. SUBJECTS: Seventeen men and 20 women (age 36-50 y, body fat 25-50%). MEASUREMENTS: In vitro basal lipolysis of subcutaneous abdominal and femoral adipocytes and plasma levels of five polychlorinated biphenyl congeners (Aroclor 1260, PCBs 118, 138, 153 and 180) and three chlorinated pesticides (dichlorodiphenyl dichloroethene (p,p'-DDE), beta-hexachlorocyclohexane (beta-HCH) and hexachlorobenzene (HCB)) were measured before and after the weight reducing program. RESULTS: Both genders showed a similar reduction in body weight (approximately 11 kg) in response to treatment, although men lost significantly more fat mass than women (mean+/-s.d., 9.4+/-4.1 vs 5.9+/-5 kg, respectively, P<0.05). Mean basal fat cell lipolysis did not vary before and after weight reduction, regardless of depots and genders. In response to weight loss, significant increases of all organochlorines investigated were observed in men, whereas only p,p'-DDE, Aroclor 1260, PCBs 153 and 180 significantly rose in women. In men, higher the increase in basal lipolysis of subcutaneous abdominal or femoral adipocytes, greater the rise in plasma levels of most pollutants (HCB, Aroclor 1260, PCBs 118, 138 and 153) was in response to weight loss (0.51<r<0.70, P<0.05). Similar positive correlations were also observed in women but only a few reached statistical significance (p,p'-DDE, PCBs 118 and 180). CONCLUSION: The weight loss-induced increase in plasma pollutant levels is related to the rise in subcutaneous abdominal and femoral adipocyte basal lipolysis, especially in men.

Abdomen↗
PubMed2001

[The transformation process among a group of heart patients followed in ergotherapy with the aim of modifying the balance of occupation].

Transformative learning is a process of adaptation that allows for profound personal change in occupational therapy clients. This process is provoked by a triggering factor, such as illness, which results in a critical reflection on values, beliefs, feelings and personal knowledge associated with the object of change (Mezirow, 1991). As part of an objective aimed at modifying the balance of occupation, nine participants were interviewed over a 6 month period to explore their processes of change. Eight concepts related to the objective of change of the balance of occupation emerged from an inductive data analysis process (Glaser and Strauss, 1967). The perception of work was interpreted by the authors as having undergone the most significant sense of transformation amongst the participants. Two other perceptions, 1) the definition of self and 2) the concept of health emerged as new elements essential to the modification of the balance of occupation. The transformation process linked to these eight concepts revealed a specific structure and sequence. The results highlight the primary role of critical reflection amongst occupational therapy clients and underline the importance of deconstructing common values and beliefs which could slow down the process of change. Moreover, the development of new values and beliefs is a vehicle for change in occupational therapy.

Adaptation, Psychological↗
PubMed2000

Direct 3D imaging of Al70.4Pd21Mn8.6 quasicrystal local atomic structure by X-ray holography

Inverse x-ray fluorescence holography was used to explore the local atomic order of a nearly perfect quasicrystal with composition Al70. 4Pd21Mn8.6. We have demonstrated the possibility of direct 3D imaging of the atomic decoration in a quasicrystal. We have obtained the average 3D environment of selected coordination shells around the Mn atoms. These results open the way to obtaining further and more complete information about the various coordination shells in complex materials by measuring multiple energy x-ray holograms at different sites.

Journal Article↗
PubMed2000

Body weight loss increases plasma and adipose tissue concentrations of potentially toxic pollutants in obese individuals.

BACKGROUND: While there appears to be a consensus among scientists and clinicians that body weight loss reduces the risk of several chronic diseases, these apparently favourable effects should be balanced against any potentially harmful side effect of weight loss. In this regard, weight loss has been shown to produce an increase in blood concentration of potentially toxic organochlorine pollutants in animals that can cause prejudice to health, but human data are lacking. METHODS: Thirty-nine obese individuals were subjected to a hypocaloric diet during 15 weeks. Blood and subcutaneous adipose tissue samples were analysed before and after treatment for 26 organochlorine compounds. A control group consisting of 57 women of similar mean age was also formed in order to compare plasma concentrations. RESULTS: Organochlorine pollutants were found in every subject and all 19 compounds detected had their plasma concentration increased following treatment (mean body weight loss 9.5 kg), 15 of which were statistically significant. When compared with a control group, five compounds increased significantly. These observations persisted after an 18 week low-fat diet/exercise program follow-up. Increases were correlated with body weight loss (-0.3 > or = r > or = -0.6, P<0.05) and adipose tissue analyses yielded similar results, as their concentration of organochlorine compounds increased following treatment. CONCLUSION: Body weight loss increases plasma and subcutaneous adipose tissue concentrations of organochlorine pesticides and PCBs in obese subjects. These results raise concerns about an undesired and potentially harmful side effect of weight loss in some obese patients who seem to be at greater risk of health problems than leaner subjects since they show higher organochlorine body burden.

Adipose Tissue↗
PubMed1983

Depth perception in Pandora's box and size illusion: evolution with age.

The aim of the experiment was to study the evolution with age (6, 8, 11 and 14 years) of pictorial depth perception in Pandora's box and to compare it with the evolution of size illusion with the same subjects and the same pictorial backgrounds. In addition to familiar size and relative position, each pictorial stimulus contained one or more of the following depth cues: linear perspective, texture gradient, and interposition. The two kinds of measurements produced different results. Size illusions, although present, did not vary with age but increased with the number of cues. Estimates of distance in Pandora's box increased with age and varied according to the type of cue present: texture gradient seemed to be critical to the amount of depth perceived. The correlation between size adjustments and distance adjustments was significant only for the two oldest groups of subjects (11 and 14 years).

Adolescent↗
PubMed1982

[Bidirectional ventricular tachycardia (arguments in favor of reentry)].

Bidirectional ventricular tachycardia, defined as the rapid alternation of the QRS complexes with successive opposing axial deviation, is a rare arrhythmia. In the rare cases which have undergone endocavitary investigations, an infrahisian origin has generally been proved. However, the mechanism of these tachycardias remains poorly understood and is discussed with respect to a new case. Bidirectional tachycardia occurred in a 79 year old woman with previous diaphragmatic and anterior wall infarction. It was a wide QRS tachycardia at 180/min with a succession of ventriculogrammes of opposing axis in the frontal plane and permanent right bundle branch block over the right precordium. The two types of tachycardia were observed, monomorphic type A or Type B or a combination of the two realising an A-B bidirectional tachycardia. The origin of these episodes, which occurred on a background of atrial tachycardia at about 100/min, was ventricular as shown by the absence of a His potential before the ventricular complexes in tachycardia. The presence of ventricular extrasystoles with relatively fixed coupling intervals, and the results of endocavitary investigation were suggestive of a reentry phenomenon ventricular extrastimuli were capable of transforming the bidirectional into monomorphic tachycardia and vice versa; this suggests that A was at times the origin of a reentry B, but protected by A, tachycardia B could be sustained. In the light of previously reported cases with documented endocavitary investigation and this new case, it seems possible to talk in terms of true "bidirectional ventricular tachycardia", a tachycardia whose mechanism is obscure but certainly not univocal.

Aged↗
PubMed1980

Aesthetic preferences: influence of perceptual ability, age and complexity of stimulus.

Aesthetic preferences for overlapping geometrical figures were studied with reference to perceptual abilities and age of 80 subjects in the context of the theory of functional pleasure. According to the working hypothesis, the level of complexity (number of crossings) of the preferred stimulus varies with the subjects' perceptual capacities as measured by an overlapping figures test and an embedded figures test. The results confirm this hypothesis with significant correlations between the two variables. Changes in preference for complexity with age (20 subjects each of 6, 8, 11, and 14 yr.) is seen as related to changes in perceptual ability. The general interpretation suggests that aesthetic preferences are partly based on the pleasure resulting from the quality of functioning of the perceptual mechanisms.

Adolescent↗
PubMedDate not supplied

Transcultural reflection on clinical teaching using an experiential teaching-learning model.

BACKGROUND: A 6-day professional development workshop was designed and implemented in China as part of a project funded by the Canadian International Development Association through the Canada-China University linkage program. METHOD: Kolb's experiential learning model was used as a framework to help Chinese nurse educators reflect on their practice as clinical teachers. RESULTS: The workshop resulted in the generation of new insights by participants into their role as clinical teachers. Chinese educators wanted to increase their links between the teaching of theory at the college and the instruction of students in the practice setting. CONCLUSION: The use of a similar approach in future professional development workshops allows presenters to identify nurses' learning needs regarding specific areas of nursing practice and education.

Canada↗