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Biomedical subjects

J Dussault

Publications and source records attributed to J Dussault.

At least 19 recordsLinked to original sources
PubMed1997

[Sensitivity and specificity of thyreostimuline (TSH) determination on filter paper for the diagnosis of hypothyroidism in the elderly].

The aim of this study was to measure the prevalence of hypothyroidism in 239 elderly patients and to determine the validity of TSH assay on blood dried on filter paper (spot-test) for the diagnosis of hypothyroidism. The sensitivity and specificity of the spot-test were evaluated in a subgroup of 177 subjects. The prevalence of hypothyroidism was 14.2% (34/239). The spot-test did not give satisfactory results for the diagnosis of hypothyroidism in elderly subjects. Due to the lack of specificity, most of the positive results were false positives and the clinician had to rely on laboratory determination of plasma TSH level to confirm hypothyroidism in half of the patients. We do not recommend the spot-test for the diagnosis of hypothyroidism in the elderly. Laboratory assay of plasma TSH is required for confirming hypothyroidism in the elderly.

Aged↗
PubMed1992

Intellectual development at age 12 years of children with congenital hypothyroidism diagnosed by neonatal screening.

Twenty-seven patients with congenital hypothyroidism diagnosed by neonatal screening were examined at the age of 12 years. The 12 patients with severe hypothyroidism at diagnosis (thyroxine < 2 micrograms/dl (< 26 nmol/L), and area-of-the-knee epiphyses < 0.05 cm2 had a lower IQ than the 15 patients with less severe hypothyroidism (mean +/- SD, 89 +/- 17 vs 104 +/- 10; p < 0.007). Comparisons of patients and siblings confirm that this difference was due to the severity of hypothyroidism.

Child↗
PubMed1992

Adipose tissue lipolysis after long-term overfeeding in identical twins.

Ten pairs of young male sedentary, non-obese, monozygotic (MZ) twins, aged 21 +/- 2 years (mean +/- s.d.), were overfed for a period of 100 days during which they ingested 4.2 MJ (1000 kcal) per day above their individual energy needs, 6 days per week. There was a mean 8.4 kg increase in body weight and the average gain in body fat reaches 5.6 kg (P less than 0.0001). A biopsy of subcutaneous abdominal fat was performed, before and after the treatment, to determine fat cell weight as well as basal and catecholamine stimulated lipolyses from collagenase isolated adipocytes. Although analysis of variance revealed an increase in abdominal fat cell weight, no significant changes were noted in basal and catecholamine-stimulated lipolyses, due to large variation among individuals, results being expressed either per cell number or corrected for cell surface area. However, significant intrapair resemblance was observed in the changes of basal and epinephrine stimulated lipolyses (ri of about 0.60 in both cases), suggesting a concordant within-pair response, despite large between-pair variation. These results support the notion that the genotype may play an important role in regulating the response of abdominal adipose cells lipolytic activity to caloric excess.

Abdomen↗
PubMed1990

The response to long-term overfeeding in identical twins.

We undertook this study to determine whether there are differences in the responses of different persons to long-term overfeeding and to assess the possibility that genotypes are involved in such differences. After a two-week base-line period, 12 pairs of young adult male monozygotic twins were overfed by 4.2 MJ (1000 kcal) per day, 6 days a week, for a total of 84 days during a 100-day period. The total excess amount each man consumed was 353 MJ (84,000 kcal). During overfeeding, individual changes in body composition and topography of fat deposition varied considerably. The mean weight gain was 8.1 kg, but the range was 4.3 to 13.3 kg. The similarity within each pair in the response to overfeeding was significant (P less than 0.05) with respect to body weight, percentage of fat, fat mass, and estimated subcutaneous fat, with about three times more variance among pairs than within pairs (r approximately 0.5). After adjustment for the gains in fat mass, the within-pair similarity was particularly evident with respect to the changes in regional fat distribution and amount of abdominal visceral fat (P less than 0.01), with about six times as much variance among pairs as within pairs (r approximately 0.7). We conclude that the most likely explanation for the intrapair similarity in the adaptation to long-term overfeeding and for the variations in weight gain and fat distribution among the pairs of twins is that genetic factors are involved. These may govern the tendency to store energy as either fat or lean tissue and the various determinants of the resting expenditure of energy.

Adult↗
PubMed1990

[Comparative study of psychometric results of 2 french speaking populations with hypothyroidism detected at birth].

The authors compare the data from the psychological assessment of a cohort of 191 French speaking hypothyroid children detected by neonatal screening: 99 were followed in Quebec and 92 in Lille, according to two independent programs. Three age levels were selected: 12-18 months, 5 and 7 years. Data were similar and, in both studies, results of the later ages were slightly lower than the norms of the tests or results obtained in control groups. In both populations correlations were found between some results and two factors related to hypothyroidism: delayed bone surface development and thyroxinemia at the time of diagnosis. On the other hand, etiology and time of treatment had no repercussions on any group results.

Bone Development↗
PubMed1990

Long-term exercise training with constant energy intake. 1: Effect on body composition and selected metabolic variables.

The effects of long-term negative energy balance generated by exercise while maintaining a constant energy intake were studied in five healthy young males (25 +/- 3 years; mean +/- s.d.). After 2 weeks of monitoring to determine habitual energy intake, they were subjected to a 100-day experimental period during which they exercised on a cycle ergometer, 6 days a week, twice a day at 55 per cent of VO2 max. The daily energy deficit was 4.2 MJ for a total of 353 MJ for the duration of the treatment. Body weight decreased from 86.7 to 78.7 kg (P less than 0.001). More than 80 per cent of the weight loss was accounted for by the reductions in fat mass. Fat-free mass did not change significantly. The data suggest that subcutaneous fat was lost about evenly from the trunk and from the limbs as estimated from skinfolds. Cardiorespiratory and metabolic responses to submaximal work loads indicate that the low intensity exercise regimen was capable of inducing some of the known adaptations of exercise training such as a decrease in plasma insulin and norepinephrine concentrations during exercise, reductions in heart rate, pulmonary ventilation and blood lactate concentration at a given exercise intensity, and an increase in skeletal muscle oxidative capacity. The energy cost of sitting and standing was not decreased in spite of the loss in body mass. However, the energy cost of submaximal cycling and walking exercises was reduced considerably. These results clearly demonstrate that it is quite possible to lose fat while preserving fat-free mass through regular prolonged exercise of moderate intensity if energy intake is kept constant at baseline level. They also emphasize the importance of the individual differences in response to negative energy balance.

Adult↗
PubMed1989

The effect of prior exercise and caffeine ingestion on metabolic rate and hormones in young adult males.

The purposes of this study were to examine (a) the effects of acute exercise on metabolic rate 24 and 48 h postexercise and (b) the interaction of acute exercise and the thermic effect of caffeine on metabolic rate and hormonal changes during the late postexercise recovery period. In six young males, who were regular consumers of caffeine, resting energy expenditure was measured before and after caffeine (5 mg.kg-1) and placebo ingestion under the following conditions: (i) control (e.g., no prior exercise), (ii) 24 h postexercise, and (iii) 48 h postexercise. Blood samples were drawn for plasma glucose, insulin, glycerol, free fatty acids, catecholamines, and thyroid hormones (triiodothyronine, thyroxine, and free thyroxine). Results showed that acute exercise did not exert a detectable effect on resting metabolic rate in the late postexercise recovery period, that is, resting metabolic rate was similar among the conditions of control (1.17 +/- 0.12 kcal.min-1), 24 h postexercise (1.16 +/- 0.12), and 48 h postexercise (1.16 +/- 0.11). Caffeine ingestion increased metabolic rate (approximately 7%), but the thermic effect was not different among the experimental conditions. Plasma insulin and norepinephrine were lower after caffeine ingestion, whereas an increase in plasma free fatty acids was noted. Other hormones and substrates did not change significantly in response to caffeine ingestion. Furthermore, the hormonal and substrate milieu was not significantly different 24 and 48 h postexercise when compared with the control condition. Our results support the view that acute exercise does not alter the resting metabolic rate in the late postexercise recovery period.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

Sensitivity to overfeeding: the Quebec experiment with identical twins.

The role of the genotype in the response to short-term overfeeding was assessed by submitted six pairs of male monozygotic twins to a 4.2 MJ (1000 kcal) per day energy intake surplus for a period of 22 consecutive days. Individual differences in fat mass and fat-free mass gains were observed in response to overfeeding but they were not randomly distributed. Indeed, the within-pair resemblance in the response was striking when compared to the heterogeneity found among the pairs in adiposity and fat-free mass gains. The intrapair resemblance in the response to overfeeding as assessed by the intraclass coefficient computed with the individual changes, reached 0.88 for total fat mass and 0.76 for fat-free mass. A similar trend for a genetically determined pattern of adaptation to overfeeding was observed for resting metabolic rate (intraclass = 0.63), thermic effect of a meal (intraclass = 0.62), and energy cost of submaximal exercise (intraclass = 0.78) when the data were analysed in terms of changes in oxygen uptake. On the other hand, no major alterations in glucose and insulin response to a glucose load or a test meal, in cardio-pulmonary adaptation to submaximal exercise and in maximal exercise tolerance were found with overfeeding. In contrast, the response of suprailiac fat cell lipolysis (intraclass of about 0.7) and heparin releasable adipose tissue lipoprotein lipase (intraclass - 0.82) varied among individuals but was highly homogeneous within genotypes. Similarly, a genotype-overfeeding interaction effect was seen for serum triglycerides (intraclass = 0.69), HDL-cholesterol (intraclass = 0.85), and the HDL-cholesterol to total cholesterol ratio (intraclass = 0.82). Multiple correlation analyses suggest that much of the variance in the response of fat mass (R = 0.65) and fat-free mass (R = 0.81) is accounted for by alterations in the energy expenditure components assessed in the study. If one takes into account the measurement errors always present in such complex studies and the fact that only a limited fraction of the energy expenditure of activity was considered by design, one can conclude that the genotype determines to a large extent the response variation to short-term overfeeding. In particular, the genotype-overfeeding interaction effect for body composition changes seems to be mediated by the various energy expenditure components, themselves characterized by significant genotype-overfeeding interaction effects.(ABSTRACT TRUNCATED AT 400 WORDS)

Adipose Tissue↗
PubMed1987

Heredity and overfeeding-induced changes in submaximal exercise VO2.

The present study investigated the role of heredity in determining changes in the energy cost of submaximal exercise in response to short-term overfeeding. Six pairs of monozygotic twins were subjected to a 1,000 kcal/day surplus for 22 days with careful experimental controls over food intake and physical activities. O2 consumption (VO2) was measured during a submaximal treadmill exercise test 165 min postprandially before and the morning after the overfeeding protocol. As expected, overfeeding induced significant increases in body weight and fat mass. No significant increase in mean exercise VO2 was observed after overfeeding. However, the interindividual variation in overfeeding-induced changes in exercise VO2 was large and not randomly distributed. When comparing intrapair variance for changes in exercise VO2 to interpair variance, a moderate to high within-pair resemblance in response, i.e., a genotype-overfeeding interaction, was observed. Changes in exercise VO2 were positively correlated with those in postexercise levels of blood catecholamines, particularly epinephrine. A negative correlation was found between changes in exercise VO2 and body fat gain. These results are consistent with the concept of a role for the sympathoadrenal system in the regulation of adaptive thermogenesis and the predisposition to store fat. Moreover, these data suggest that the sensitivity to adapt in exercise energy expenditure after overfeeding is inherited to a significant extent.

Adult↗
PubMed1986

Genotype dependency of the thermic effect of a meal and associated hormonal changes following short-term overfeeding.

The purpose of this experiment was to assess the effects of short-term overfeeding (mixed diet) on the thermic effect of a meal (TEM) and associated hormonal changes and to investigate the role of the genotype in the observed changes. Six pairs of male sedentary monozygotic (MZ) twins consumed an extra 1,000 kcal per day over their individual level of energy expenditure while maintaining a sedentary existence. Resting metabolic rate (RMR) and TEM following a 4.2 MJ meal challenge was measured before and after 22 days of overfeeding. RMR did not change significantly (7% elevation) in response to the positive caloric stimulus, whereas significant increases (P less than 0.01) in TEM were observed. Moreover, postprandial insulin and glucose responses were not modified. Overfeeding did not significantly alter catecholamine levels but induced significant elevations in plasma levels of T3 and T4 (P less than 0.05). Changes in RMR exhibited moderate but nonsignificant within twin pair resemblance in response whereas significant within pair resemblance was noted in the magnitude of TEM changes induced by overfeeding (P less than 0.05). Hormonal responses exhibited a weaker genotype dependency. These results suggest that short-term overfeeding can induce an elevation in TEM with accompanying increases in T3 and T4. Large individual response variation in metabolic and hormonal measures were observed. The similarity of response within twin pairs suggests that sensitivity to change in TEM induced by short-term overfeeding is genetically influenced.

Adult↗
PubMed1986

Heredity and changes in hormones and metabolic rates with short-term training.

The purpose of this experiment was to assess the effects of a 22-day training program on resting metabolic rate (RMR), thermic effect of a meal (TEM), and associated hormonal changes. Six pairs of male monozygotic twins were submitted to a 22-day ergocycle exercise program designed to induce a deficit in energy balance of 4.2 MJ per day. RMR and TEM after a 4.2-MJ meal challenge were measured before and after training. Results indicated that RMR and TEM did not change significantly, although a large variation in response between twin pairs was observed. Moreover, training reduced (P less than 0.05) basal and postprandial insulin response, plasma thyroid hormones triiodothyronine (T3), thyroxine (T4), and FT4 (P less than 0.05). Absolute changes in RMR and TEM exhibited significant within-pair resemblance in response, with intraclass correlations reaching r = 0.81 (P less than 0.05) and r = 0.72 (P less than 0.05), respectively. Changes in T4 and FT4 also exhibited moderate within-pair resemblance (0.42 less than or equal to r less than or equal to 0.71). These results suggest that short-term exercise training does not modify RMR and TEM but can significantly decrease plasma levels of insulin and thyroid hormones. Moreover, the similarity of response within twin pairs suggests that heredity plays a role in determining RMR, TEM, and thyroid hormone adaptation to exercise training generating a negative energy balance.

Adolescent↗
PubMed1982

Effect of diet and exercise on norepinephrine-induced thermogenesis in male and female rats.

Male and female rats were fed standard laboratory chow or a highly palatable diet (cafeteria diet) for 10 wk. The cafeteria diet caused an increase in caloric intake and in body weight, and it induced thermogenesis that was associated with elevated plasma triiodothyronine (T3) levels, increased brown adipose tissue size, and enhanced metabolic response to norepinephrine. For a comparable caloric intake, body-weight gain was significantly greater in female than in male rats possibly because of difference in thermogenesis as suggested by the response to norepinephrine. Exercise training (swimming 2 h/day for 10 wk) reduced food intake and body-weight gain and failed to increase norepinephrine-induced thermogenesis in rats fed laboratory chow. In animals fed the cafeteria diet, food intake and body-weight gain were also reduced by exercise training, which at the same time diminished the diet-induced thermogenesis as evidenced by the diminution of 1) brown fat hypertrophy, 2) the elevation of plasma T3, and 3) the hyperthermic response to injected norepinephrine. It is suggested that the thyroid hormone and catecholamines through their actions on the brown adipose tissue are the important regulatory of thermogenesis. Exercise training would reduce the diet-induced thermogenesis by preventing increased T3 production. Enhanced thermogenesis may be considered an adaptive reaction as it serves to reduce fat deposition in animals fed cafeteria diet and to promote nonshivering heat production in the cold. On the other hand, exercise training reduces thermogenesis and thus prevents energy wasting.

Adipose Tissue↗
PubMed1969

Aneurysms of the internal carotid artery simulating pituitary tumours. Report of two cases.

Two patients suffering from aneurysms of the internal carotid artery simulating pituitary tumours are reported. One of these was a 17-year-old boy with a mycotic aneurysm of the right internal carotid artery causing failure of growth and pubertal maturation. The second was a 53-year-old woman with a left internal carotid artery aneurysm, probably of atherosclerotic origin, who had evidence of anterior pituitary insufficiency.In both cases there was paresis of extraocular muscles and one patient had bitemporal hemianopsia. While lateral radiographs of the skull suggested intrasellar calcification in each case, further roentgenological investigation established that this calcification was actually extrasellar, and carotid arteriograms demonstrated the presence of an internal carotid aneurysm in each case. Investigations of the endocrine system confirmed the presence of anterior pituitary insufficiency in both patients, and diabetes insipidus became evident in one patient after cortisone therapy was commenced.This lesion, while rare, may be difficult to differentiate from a pituitary tumour. It is likely that this syndrome depends on aneurysmal expansion to the region of the sella turcica with compression of the pituitary gland itself, as well as the optic fibres.

Adolescent↗
PubMed1969

Suppurative thyroiditis: an unusual case caused by Actinomyces naeslundi.

A case of suppurative thyroiditis due to A.naeslundi is recorded. The clinical features (including the difficulty in establishing a clinical diagnosis) have been noted. This is the first instance of A.naeslundi being considered the etiological agent of actinomycosis of the thyroid. It is also the first report incriminating A.naeslundi as a pathogen, since up to now it was considered only a saprophyte.The etiological role of A.naeslundi in this case of suppurative thyroiditis is strongly supported by the following findings:1. A.naeslundi was isolated without the presence of other pathogenic micro-organisms.2. A sulphur granule was demonstrated in the caseous pus after incision of the abscess.3. There was a favourable response to specific antibiotic therapy.

Actinomyces↗