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Biomedical subjects

M Curé

Publications and source records attributed to M Curé.

At least 19 recordsLinked to original sources
PubMed1994

Effect of ingestion pattern on rehydration and exercise performance subsequent to passive dehydration.

Six male volunteers performed three tests, each comprising a passive heating session to obtain dehydration (loss of 2.6% body mass), followed by exercise on a treadmill until exhaustion (50% of maximal oxygen consumption) in a warm environment (dry bulb temperature 35 degrees C, relative humidity 20%-30%). In one test, the subjects exercised without rehydration (Dh). In the two other tests, 50% of the fluid lost in the dehydration session was replaced by drinking mineral water given either in one amount [913 (SEM 23) ml] before the exercise (Rh1) or divided into four equal portions [228 (SEM 5) ml] before the exercise and on three occasions at 15-min intervals during exercise (Rh4). Rehydration increased exercise duration in Rh1 compared to Dh [112 (SEM 7) min and 82 (SEM 3) min, respectively; P < 0.05]. The difference was not significant with Rh4 [103 (SEM 9) min]. A restoration of the time course of changes in plasma volume, plasma osmolality, heart rate and rectal temperature occurred immediately in Rh1 and as delayed in Rh4 until after 60 min of exercise. Our results demonstrated that the swift replacement of the fluid loss in the dehydrated subjects was beneficial to exercise performance by rapidly correcting the disturbances in body fluid balance.

Adult↗
PubMed1994

Regional specificity of the long-term variation of tyrosine hydroxylase protein in rat catecholaminergic cell groups after chronic heat exposure.

The present study was carried out to investigate the effect of chronic heat exposure on tyrosine hydroxylase (TH) protein content in catecholaminergic rat brain-stem areas such as the anterior (LCA) and posterior (LCP) locus coeruleus, the substantia nigra (SN), the ventral tegmental area, and the dorsomedial (DMM) and the ventrolateral medulla and in the adrenal gland (AG). Male Sprague-Dawley rats were exposed to 34 degrees C during 3, 7, or 14 days. Controls were kept at 25 degrees C for the same period. In the LCA, TH content was decreased on day 7 (-34%) and 14 (-37%) of heat exposure. In the SN, TH protein content was decreased on day 7 (-25%) and 14 (-20%) after 34 degrees C. In the DMM cell group, 14 days at 34 degrees C produced a decrease (-20%) of TH content. In all of these structures, TH content variations were correlated with body temperature variations. In the AG, TH content increased progressively to peak (+31%) after 14 days of chronic heat exposure. This increase was also associated with body temperature modification. The selective and body temperature-related response to long-term TH protein content variations following chronic heat exposure observed in the LCA, SN, DMM, and AG could represent an adaptive physiological response of these catecholaminergic cells.

Adrenal Glands↗
PubMed1992

Behavioral heterogeneity in Sprague-Dawley rats.

Because of consistent individual differences in animal behavior, it is often difficult to interpret experimental data. We therefore attempted to rank Sprague Dawley rats by a hierarchical ascendant clustering technique using data from avoidance conditioning and open-field testing (scores of exploratory activity before, during, and after an unpredictable noise stress, and calculated stress-related inhibition). This procedure allowed partition of the animal population into distinctive groups and subgroups, extremes being represented by low avoidance-low emotional and high avoidance-high emotional animals. These results are in discrepancy with others showing an opposite pattern of emotional responses in rat lines selectively bred for low or high avoidance. Considering the psychophysiological variability of the animal population in experimental designs may thus be more informative than classical statistical methods, particularly in the evaluation of drug effects or environmental adaptation.

Animals↗
PubMed1991

Plasma atrial natriuretic peptide and vasopressin during thermal dehydration in supine posture.

After 30 minutes spent in an upright posture six healthy male subjects underwent two 130-minute experiments in a supine posture, the first in thermoneutral conditions (TC) and the second, 15 days later, in a hot environment (HE) in order to obtain a water loss of 2.5% body weight. In thermoneutral conditions, the supine posture induced plasma volume expansion, resulting in slightly lowered plasma vasopressin (AVP) levels and higher plasma atrial natriuretic peptide (ANP) levels, compared to the values obtained in the upright posture (P less than 0.05). During hot environment, the sweating-induced dehydration led to a significant reduction of plasma volume expansion and to an increase in rectal temperature and plasma osmolality (P less than 0.05). Plasma vasopressin levels were higher at the end of the heat exposure (P less than 0.05) but natriuretic peptide levels did not change, compared to the values observed in the upright posture. These data suggest that plasma volume reduction induced by thermal dehydration may limit the natriuretic peptide release, which occurs after changing from the upright to a supine position.

Adult↗
PubMed1988

Body temperature and plasma prolactin and norepinephrine relationships during exercise in a warm environment: effect of dehydration.

The effects of euhydration (Eh) and light (Dh1) and moderate (Dh2) dehydrations on plasma prolactin (PRL) levels were studied in 5 young male volunteers at rest and during exercise to exhaustion (50% of VO2max) in a warm environment (Tdb = 35 degrees C, rh = 20-30%). Light and moderate dehydrations (loss of 1.1 and 1.8% body respectively) were obtained before exercise by controlled hyperthermia. Compared to Eh, time for exhaustion was reduced in Dh1 and Dh2 (p less than 0.01) and rectal temperature (Tre) rose faster in Dh2 (p less than 0.05). Both venous plasma PRL and norepinephrine (NE) increased during exercise at any hydration level (p less than 0.05). Plasma PRL reached higher values after 40 and 60 min in Dh2 and Dh1 (p less than 0.05). Plasma NE values were higher in Dh2 at rest and at the 40th min during exercise (p less than 0.05). Plasma PRL was linearly correlated to Tre and plasma NE (p less than 0.001) but unrelated to plasma volume variation and osmolality. Our results provide further evidence for the major effect of body temperature in exercise-induced PRL changes. Moreover, the plasma PRL-NE relationship suggests that these changes may result from central noradrenergic activation.

Adult↗
PubMed1982

Spontaneous pituitary tumors in the Wistar/Furth/Ico rat strain. An animal model of human prolactin adenoma.

Twenty-three spontaneous pituitary tumors in 58 rats of Wistar/Furth/Ico strain were studied. The incidence is 38% in rats older than 10 months; it rises with age, with a maximum at 28-32 months (68.7%) and is higher in females (71.4%) than in males (35%) over 17 months. Light-microscopic and immunocytochemical studies revealed 20 prolactinomas in 19 rats (19/58, 32.7%) and 3 spongiocytic nonimmunostaining adenomas (3/58, 5.2%). The prolactinoma is often hemorrhagic. The cells, often arranged in sheets and agranular, are mostly positive with anti-rat prolactin (rPRL) serum. They have few polymorph granules and a well-developed rough endoplasmic reticulum. In the spongiocytic adenoma, the cells are arranged in cords. Their cytoplasm is slightly vacuolated. In prolactinoma-bearing rats, the mean plasma PRL value was 213 +/- 72.5 microgram/1 (SEM) (N = 15 +/- 1.8 microgram/1 [SEM]). A linear correlation was found between the logarithm of the tumoral pituitary weight or of the tumor size and the logarithm of the prolactinemia. Because of the analogies between these rat prolactinomas and 57 human prolactinomas, the Wistar/Furth/Ico rat strain is considered as a good animal model.

Adenoma↗
PubMed1979

[Heat-induced salivary gland hypertrophy: change during chronic heat exposure (34 degrees C). (author's transl)].

1 A slight rise in ambient temperature (34 degrees C) increased saliva secretion in the rat and this was accompanied by licking behavior, thus increasing heat loss by evaporation. 2 The rise in ambient temperature was accompanied by a hypertrophy of the submaxillary glands (Fig.1, 2), arising from activation of seromucous acini (Fig. 4, 5). 3 The hypertrophy reached a maximum after 2 to 4 days of heat exposure (Fig. 2); it was followed by a slow decrease. Normal values were obtained only after at least 3 weeks in the climatic chamber (Fig. 2, 3), which agreed with behavioral observations. Increased secretion of saliva may help to increase heat loss and maintain survival in a hot environment. 4 The absence of morphological changes in the sublingual g and and the evolution of the granular circonvoluted tubules (Fig. 6) contrast greatly with the hypertrophy of the submaxillary acinus. It is possible that heat-induced saliva secretion may be controlled by both sympathetic and parasympathetic systems.

Animals↗