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J Lévesque

Publications and source records attributed to J Lévesque.

13 recordsLinked to original sources
PubMed2004

Neural basis of emotional self-regulation in childhood.

Emotional self-regulation plays a pivotal role in socialization and moral development. This capacity critically depends on the development of the prefrontal cortex (PFC). The present functional magnetic resonance imaging study was conducted to identify the neural circuitry underlying voluntary self-regulation of sadness in healthy girls (aged 8-10). A 2 x 2 factorial design was implemented with Emotion (No Sadness vs. Sadness) and Regulation (No Reappraisal vs. Reappraisal) as factors. In the No Reappraisal conditions, subjects were instructed to react normally to neutral and sad film excerpts whereas in the Reappraisal conditions, subjects were asked to voluntarily suppress any emotional reaction in response to comparable stimuli. A significant interaction of the Emotion and Regulation factors revealed that reappraisal of sad film excerpts was associated with bilateral activations of the lateral PFC (LPFC; Brodmann areas [BA] 9 and 10), orbitofrontal cortex (OFC; BA 11), and medial PFC (BA 9 and 10). Significant loci of activations were also detected in the right anterior cingulate cortex (BA 24/32) and right ventrolateral PFC (BA 47). In an identical study previously conducted by our group in adult women [Biol Psychiatry 53 (2003) 502], reappraisal of sad film excerpts was associated with activation of the right OFC (BA 11) and right LPFC (BA 9). The greater number of prefrontal loci of activation found in children relative to adults during voluntary self-regulation of sadness may be related to the immaturity of the prefronto-limbic connections in childhood.

Behavior↗
PubMed2004

Ability of peripheral DXA measurement to diagnose osteoporosis as assessed by central DXA measurement.

In order to evaluate the utility of peripheral measurement of bone mineral density (BMD) in the diagnosis of osteoporosis, we measured BMD at the spine and femoral neck with central dual-energy X-ray absorptiometry (DXA), at phalanx with AccuDXA (Schick) as well as proximal and distal forearm with pDXA (Norland) in 835 women ranging in age from 20 to 85 yr. In receiver operating characteristic (ROC) curves, where a positive case was defined as a T-score < or = -2.5 either on spine or femoral neck, the areas under the curve were not significantly different between sites. At a T-score of -2.5 as determined by each peripheral apparatus, sensitivity and specificity were, respectively, 0.39 and 0.95 for phalanx and 0.75 and 0.85 for proximal forearm whereas they were 0.42 and 0.96 for distal forearm. Using optimal absolute BMD cutoff values improved the results. Sensitivity and specificity were, respectively, 0.79 and 0.83 for phalanx at an absolute BMD value of 0.436 and 0.84 and 0.79 for proximal forearm at a value of 0.703, whereas they were 0.90 and 0.75 for distal forearm at a value of 0.208. Combining the two forearm measurements improves the results slightly. At cutoff values of 0.641 and 0.252, respectively for proximal and distal forearms, sensitivity was 0.83 and specificity was 0.84. Therefore, a peripheral measurement of BMD together with a good clinical evaluation of the osteoporosis risk profile of the patient, can be an interesting tool for the diagnosis of osteoporosis in areas where central DXA is not available.

Absorptiometry, Photon↗
PubMed2003

Neural correlates of sad feelings in healthy girls.

Emotional development is indisputably one of the cornerstones of personality development during infancy. According to the differential emotions theory (DET), primary emotions are constituted of three distinct components: the neural-evaluative, the expressive, and the experiential. The DET further assumes that these three components are biologically based and functional nearly from birth. Such a view entails that the neural substrate of primary emotions must be similar in children and adults. Guided by this assumption of the DET, the present functional magnetic resonance imaging study was conducted to identify the neural correlates of sad feelings in healthy children. Fourteen healthy girls (aged 8-10) were scanned while they watched sad film excerpts aimed at externally inducing a transient state of sadness (activation task). Emotionally neutral film excerpts were also presented to the subjects (reference task). The subtraction of the brain activity measured during the viewing of the emotionally neutral film excerpts from that noted during the viewing of the sad film excerpts revealed that sad feelings were associated with significant bilateral activations of the midbrain, the medial prefrontal cortex (Brodmann area [BA] 10), and the anterior temporal pole (BA 21). A significant locus of activation was also noted in the right ventrolateral prefrontal cortex (BA 47). These results are compatible with those of previous functional neuroimaging studies of sadness in adults. They suggest that the neural substrate underlying the subjective experience of sadness is comparable in children and adults. Such a similitude provides empirical support to the DET assumption that the neural substrate of primary emotions is biologically based.

Behavior Therapy↗
PubMed2001

Neural correlates of conscious self-regulation of emotion.

A fundamental question about the relationship between cognition and emotion concerns the neural substrate underlying emotional self-regulation. To address this issue, brain activation was measured in normal male subjects while they either responded in a normal manner to erotic film excerpts or voluntarily attempted to inhibit the sexual arousal induced by viewing erotic stimuli. Results demonstrated that the sexual arousal experienced, in response to the erotic film excerpts, was associated with activation in "limbic" and paralimbic structures, such as the right amygdala, right anterior temporal pole, and hypothalamus. In addition, the attempted inhibition of the sexual arousal generated by viewing the erotic stimuli was associated with activation of the right superior frontal gyrus and right anterior cingulate gyrus. No activation was found in limbic areas. These findings reinforce the view that emotional self-regulation is normally implemented by a neural circuit comprising various prefrontal regions and subcortical limbic structures. They also suggest that humans have the capacity to influence the electrochemical dynamics of their brains, by voluntarily changing the nature of the mind processes unfolding in the psychological space.

Adult↗
PubMed2000

Evaluation of prostatic specific antigen and digital rectal examination as screening tests for prostate cancer.

BACKGROUND: The 11,811 first visits and 46,751 annual follow-up visits performed since 1988 were analyzed in order to assess the efficacy of serum prostatic specific antigen (PSA) and digital rectal examination (DRE) for diagnosis of prostate cancer. METHODS: At first visit, screening included DRE and measurement of PSA using 3.0 ng/ml as upper limit of normal, demonstrated as optimal value in the course of the study. Transrectal echography of the prostate (TRUS) was performed only if PSA and/or DRE was abnormal. For elevated PSA, biopsy was performed only if PSA was above the value predicted from prostatic volume measured by TRUS. At follow-up visits, it was decided during the course of the study to use PSA alone. RESULTS: PSA was above 3.0 ng/ml in 16.6% and 15.6% of men at first and follow-up visits, respectively. Prostate cancer was found in 2.9% of men invited for screening at first visit and in only 0.4% of men at follow-up visits for a 7.1-fold decrease at follow-up visits done up to 11 years. PSA alone allowed to find 90.5% and 90. 0% of cancers at first and follow-up visits, respectively, compared to 41.1% and 25.0% by DRE alone. In the presence of normal PSA, 344 and 1,919 DREs are needed to find one prostate cancer at first and follow-up visits, respectively. A significant improvement in stage of the disease is found at follow-up (215 cancers) compared to first visits (337 cancers). Comparison made between men invited for screening and those who were not invited but screened showed no significant difference in terms of incidence and prevalence of prostate cancer as well as diagnosis of cancer as a function of age or as a function of PSA, DRE, and TRUS data. The cost for finding one case of prostate cancer is estimated at Can $2,420 and Can $7, 105 (first and follow-up visits, respectively, when PSA is used as prescreening). CONCLUSIONS: PSA used as prescreening and followed by DRE and TRUS when PSA is abnormal is highly efficient in detecting prostate cancer at a localized (potentially curable) stage since 99% of the cancers diagnosed were at such a localized stage, thus practically eliminating the diagnosis of metastatic and noncurable prostate cancer. The approach used is highly reliable, sensitive, efficient, and acceptable by the general population. The detection of clinically nonsignificant cancer is an exception.

Age Factors↗
PubMed1999

Screening decreases prostate cancer death: first analysis of the 1988 Quebec prospective randomized controlled trial.

BACKGROUND: The 46,193 men aged 45 to 80 years registered in the electoral roll of Quebec City and its Metropolitan area were randomized in November 1988 between screening and no screening in a study aimed of assessing the impact of prostate cancer screening on cause-specific death. METHODS: At first visit, screening included measurement of serum prostatic specific antigen (PSA) using 3.0 ng/ml as upper limit of normal and a digital rectal examination (DRE). Transrectal echography of the prostate (TRUS) was performed only if PSA and/or DRE was abnormal and biopsy was then done, only if PSA was above the predicted PSA value. At follow-up visits, PSA alone was used as prescreening. RESULTS: 137 deaths due to prostate cancer occurred between 1989 and 1996, inclusively, in the 38,056 unscreened men while only 5 deaths were observed among the 8,137 screened individuals. The prostate cancer death rates during the eight-year period were 48.7 and 15 per 100,000 man-years in the unscreened and screened groups, respectively, for a 3.25 odds ratio in favor of screening and early treatment (P < 0.01). CONCLUSIONS: If PSA screening is started at the age of 50 years (or 45 years in the higher risk population), annual or biannual PSA alone is highly efficient to identify the men who are at high risk of having prostate cancer. Coupled with treatment of localized disease, this approach demonstrates, for the first time, that early diagnosis and treatment permits a dramatic decrease in deaths from prostate cancer.

Aged↗
PubMed1998

Effects of buffers on milk fatty acids and mammary arteriovenous differences in dairy cows fed Ca salts of fatty acids.

Ten Holstein cows in early lactation were used in a replicated 5 x 5 Latin square design to study the effects of MgO and three buffers added to diets containing Ca salts of canola oil fatty acids. Treatments were 1) control (basal diet; no buffer). 2) 1.1% NaHCO3 plus 1.1% KHCO3, 3) 1.9% NaHCO3, 4) 0.5% MgO, and 5) 2.0% Na sesquicarbonate (percentage of dry matter). The control diet contained 53% grass silage, 43% concentrate, and 4% Ca salts. Body weight, intake, milk yield, and percentages of milk fat, protein, and lactose were unaffected by treatments. Buffers and MgO tended to increase triacylglycerol extraction by the mammary gland and changed the proportions of some fatty acids in milk. Arterial concentrations of acetate and triacylglycerol were correlated with their respective arteriovenous differences. Extraction by the mammary gland was high for acetate (approximately equal to 58.2%), triacylglycerol (approximately equal to 47.3%) propionate (approximately equal to 34.6%), and glucose (approximately equal to 24.3%). Extraction of free fatty acids, phospholipids, or cholesterol was negligible. Mammary triacylglycerol arteriovenous difference tended to be higher than when MgO was fed than when NaHCO3 was fed. Sodium sesquicarbonate, NaHCO3, and the blend of bicarbonate buffers increased C18:2 in milk fat when compared with the control treatment. The concentration of C18:2 in milk fat decreased when MgO was fed, but the ratio of cis-C18:1 to trans-C18:1 increased compared with effects of dietary NaHCO3. Medium-chain fatty acids in milk fat tended to be higher than Na sesquicarbonate than with NaHCO3. Buffers and MgO modified the profiles of fatty acids in milk.

Acetates↗
PubMed1997

Dietary soybeans extruded at different temperatures: milk composition and in situ fatty acid reactions.

Twenty-four multiparous Holstein cows, 4 of which were ruminally fistulated, were assigned to one of four diets containing full-fat soybeans, either raw or extruded at 120, 130, or 140 degrees C. Our hypothesis was that the extrusion of full-fat soybeans, as well as the extrusion temperature, would affect the bypass of fatty acids in the rumen and, thus, would modify the fatty acid profile of milk fat. Total mixed diets containing 23.7% soybeans (percentage of DM) were fed for 8 wk. Milk yield was lower, and the proportion of milk CP was higher, for cows fed raw soybeans than for cows fed extruded soybeans. Compared with raw soybeans, extruded soybeans increased the concentration of delta-11-trans-C18:1 from 2.72 to 11.41% in milk fat but had no effect on yield or percentage of milk fat. Polyunsaturated fatty acids of raw soybeans disappeared more rapidly than did those of extruded soybeans from bags incubated in the rumen of fistulated cows. However, more delta-11-trans-C18:1 and C18:0 appeared in bags containing extruded soybeans than in bags containing raw soybeans. Extrusion of full-fat soybeans influenced the metabolism of fatty acids in the rumen and the fatty acid profile of milk fat, but the temperature of extrusion had only minor effects on these parameters.

Animal Feed↗
PubMed1994

A pilot, early angiographic patency study using a direct thrombin inhibitor as adjunctive therapy to streptokinase in acute myocardial infarction.

BACKGROUND: The success of streptokinase in acute myocardial infarction is hampered by the high failure rate to achieve early reperfusion. This study evaluates the possible benefit of Hirulog (Biogen, Cambridge, Mass), a direct thrombin inhibitor, as adjunct therapy to streptokinase to enhance early patency and prevent rethrombosis. Heparin has been shown to be of very limited benefits in this setting. METHODS AND RESULTS: Forty-five patients were randomized to Hirulog or heparin (2:1 ratio). Coronary angiography documented a TIMI 2 or 3 flow after 90 minutes in 77% of the patients treated with Hirulog and streptokinase and in 47% of patients treated with heparin and streptokinase (P < .05) and after 120 minutes in 87% and 47% of patients, respectively (P < .01). TIMI 3 flow was established in 77% of patients with Hirulog compared with 40% with heparin (P < .02). The clinical outcome and the bleeding rate was also favorable to Hirulog; no reocclusion was observed at late angiography performed 4.7 days later. CONCLUSIONS: Hirulog in this pilot study significantly improved the early patency rate of the infarct-related artery with a favorable clinical profile. This new direct thrombin inhibitor exhibits promise as adjunctive therapy to thrombolysis.

Coronary Angiography↗
PubMed1993

Hypersensitivity pneumonitis-like reaction among workers exposed to diphenylmethane [correction to piphenylmethane] diisocyanate (MDI).

Isocyanates are well documented as a cause of occupational asthma. A hypersensitivity pneumonitis type of reaction has also been reported but only in a few isolated cases. We investigated nine subjects who complained of respiratory and general symptoms related to workplace exposure. All the subjects had worked in a plant where a resin based on diphenylmethane diisocyanate (MDI) is used in the manufacture of woodchip boards. They underwent inhalation challenges using the MDI resin for progressively increasing periods of time on separate days. In eight subjects, exposure to subirritant amounts of MDI induced a pattern of reaction consistent with hypersensitivity pneumonitis, i.e., significant falls in both FEV1 and FVC associated with a rise in body temperature (> 38 degrees C) and an increase in blood neutrophils (> +2,500/mm3). Bronchoalveolar lavage, performed in two subjects 24 h after the end of challenge exposure, revealed an increase in lymphocytes and neutrophils. Specific immunoglobulin G (IgG) and IgE antibodies to MDI human serum albumin (HSA) conjugates were present in all subjects. We conclude that the MDI resin caused an hypersensitivity pneumonitis type of reaction in at least eight (4.7%) of the 167 potentially exposed workers employed in the plant. These findings indicate that in some workplaces, a hypersensitivity pneumonitis type of reaction may be a more frequent consequence of isocyanate exposure than is usually thought.

Adult↗
PubMed1992

Responses of serum folates of preruminant and ruminant calves to a dietary supplement of folic acid.

The effect of dietary supplemental folic acid on serum folates of preruminant and ruminant calves was studied. In Trial 1, doses of 0, .07, .14, .28, and .56 mg of folic acid per kilogram of BW were added to the milk of preruminant calves. In Trial 2, doses of 0, .5, 1, 2, and 4 mg of folic acid per kilogram of BW were incorporated into the concentrates of ruminant heifers. In the first part of each trial, serum folates were determined in blood samples taken 0, 1, 2, 4, 8, 16 (both trials), and 32 h (Trial 2) after a single meal supplemented with folic acid. In the second part of the two trials, the supplement of folic acid was given in feed during seven consecutive days. Blood samples were taken the day before the trial and subsequently every day during 7 d. In preruminant and ruminant calves, the area under the curve and the peak of concentration of serum folates after a meal increased with the dose ingested (P less than or equal to .05, linear and quadratic effect of doses, respectively) but the amount of folic acid needed to obtain a similar response was lower for preruminant than for ruminant calves. In preruminants, the time to reach the maximal concentration was 3 to 4 h after the meal, whatever the dose ingested (P less than or equal to .05), whereas in ruminants this time decreased with the dose ingested (quadratic effect of treatment, P less than or equal to .05).(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗
PubMedDate not supplied

[Experiences in Haiti].

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Ambulatory Care Facilities↗