References of "Legros, Jean-Jacques"
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See detailMetamorphosis of acromegaly to a non-functioning pituitary adenoma
Valdes Socin, Hernan Gonzalo ULg; Stevenaert, Achille ULg; Legros, Jean-Jacques ULg et al

in 5th European Congress of Endocrinology - Abstract book (2001)

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See detailMelatonine. II. Actions physiologiques et therapeutiques
Bruls, E.; Crasson, Marion ULg; Van Reeth, O. et al

in Revue Médicale de Liège (2000), 55(9), 862-70

Melatonin is a hormone mainly secreted by the pineal gland during the dark phase of the light-dark cycle. The most known function of melatonin in mammals is to transmit information concerning light-dark ... [more ▼]

Melatonin is a hormone mainly secreted by the pineal gland during the dark phase of the light-dark cycle. The most known function of melatonin in mammals is to transmit information concerning light-dark cycles playing the role of an active neuroendocrine transducer of environmental information. Given this chronobiologic role of pineal melatonin, it seems to be useful in the management of shift work, jet lag and some sleep disorders. In vitro like in vivo melatonin seems to be effective as an antioxidant and oncostatic agent. Melatonin may provide protection against aging process, degenerative diseases, cancer and play a role also in sexual maturation, reproduction, immune function and psychiatric illness. The administration of melatonin in the jet-lag syndrome is well codified. Further clinical research is needed for a better understanding and definition of other indications, treatment regimens and safety of the hormone. The aim of this paper is to review the current knowledge on its clinical implications. [less ▲]

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See detailMelatonine. I. Physiologie de la secretion
Bruls, E.; Crasson, Marion ULg; Legros, Jean-Jacques ULg

in Revue Médicale de Liège (2000), 55(8), 785-92

Melatonin is a hormone mainly secreted by the pineal gland during the dark phase of the light-dark cycle. The best known function of melatonin in mammals is to transmit information concerning light-dark ... [more ▼]

Melatonin is a hormone mainly secreted by the pineal gland during the dark phase of the light-dark cycle. The best known function of melatonin in mammals is to transmit information concerning light-dark cycles playing the role of an active neuroendocrine transducer of environmental information. Although melatonin circadian rhythm is endogenous, based on 25 hour cycles, it is modulated by light-dark cycle. During the day, the light signal is sent to the pineal gland through a special neuronal pathway and inhibits melatonin secretion. During the night, the last neuron of this pathway which is coming from the cervical ganglion superior releases nonadrenalin in the interstitium. Nonadrenalin stimulates melatonin synthesis through cAMP accumulation. Some factors other than light can also influence melatonin levels. Electromagnetic fields, age, male sex, Cushing syndrome, hypogonadotrophic hypogonadism, alcoholism seem to be associated with lower melatonin secretion. Female sex, hypergonadotrophic hypogonadism, sport and fasting seem to be linked to higher melatonin secretion. Some pathologies and drugs can modulate some steps of the neuroanatomic pathway of melatonin synthesis. Stress has no effect. The influence of weight and height is still investigated. Once released, melatonin can act on different organs through specific receptors (retina, supra-chiasmatic nucleus, hypophysis, brain, blood vessels, digestive tract, ovaries). [less ▲]

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See detailExperimental gerontology in Belgium: from model organisms to age-related pathologies
Toussaint, Olivier; Baret, P. V.; Brion, J.-P. et al

in Experimental Gerontology (2000), 35(8), 901-916

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See detailEffect of nicotine on rat gingival fibroblasts in vitro
Lahmouzi, Jamila ULg; Simain-Sato, Franklin ULg; Defresne, Marie-Paule ULg et al

in Connective Tissue Research (2000), 41(1), 69-80

Nicotine from 3 to 5 mM affects growth and survival rate of rat gingival fibroblasts in vitro. Ultrastructural analysis revealed dilated mitochondria and vacuolization in treated cells, suggestive of ... [more ▼]

Nicotine from 3 to 5 mM affects growth and survival rate of rat gingival fibroblasts in vitro. Ultrastructural analysis revealed dilated mitochondria and vacuolization in treated cells, suggestive of necrosis, but increased apoptosis was also revealed by cytometry. On the basis of this in vitro study, it appear that tobacco, through its component nicotine, may directly affect various functions of rat gingival fibroblasts [less ▲]

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See detailOxytocin receptor of small cell carcinoma of human lung cell lines
Pequeux, Christel ULg; Breton, Christophe; Hagelstein, Marie-Thérèse ULg et al

in Pflügers Archiv : European Journal of Physiology (2000), 440/6

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See detail50 Hz Magnetic Field Exposure Influence on Human Performance and Psychophysiological Parameters: Two Double-Blind Experimental Studies
Crasson, Marion ULg; Legros, Jean-Jacques ULg; Legros, Willy ULg et al

in Bioelectromagnetics (1999), 20(8), 474-86

Two double-blind studies were performed to examine magnetic field (MF) exposure effects and to determine the impact of temporal variation (continuous vs. intermittent exposure) of 100 mu T(rms) 50 Hz MF ... [more ▼]

Two double-blind studies were performed to examine magnetic field (MF) exposure effects and to determine the impact of temporal variation (continuous vs. intermittent exposure) of 100 mu T(rms) 50 Hz MF diurnal exposure on psychological and psychophysiological parameters in healthy humans. Three cephalic exposure sessions of 30-min, i.e., sham, continuous, and intermittent (15 s ON/OFF cycles) MF conditions, were involved. Each subject participated in all sessions, which were spaced at 1-wk intervals. In each session, mood ratings and performance measures were obtained before, during, or after exposure and several electrophysiological data (event-related brain potentials [ERP]) were recorded after each exposure session. These criteria were chosen to evaluate sensory functions as well as automatic and voluntary attentional processes. In experiment 1, 21 healthy male volunteers (20 to 27 years of age) were studied. Ten subjects were exposed at 13:30 h, and 11 subjects were exposed at 16:30 h. Statistically significant changes in the amplitude of ERP were observed after MF exposure in the dichotic listening task, indexing selective attention processes. Eighteen of the 21 original male volunteers took part in experiment 2, undertaken to better understand the results related to information processing involved in selective attention and control for ultradian rhythmicity. Exposure time for all the subjects was at 13:30 h. The analysis of the data again revealed significant amplitude changes of the ERP recorded in the dichotic listening task. Moreover, they demonstrated ERP latency and reaction time slowing in the oddball paradigm, a visual discrimination task after real MF exposure. These results also indicate that a low level 50 Hz MF may have a slight influence on event-related potentials and reaction time under specific circumstances of sustained attention. [less ▲]

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See detailCulture of Gingival Fibroblasts on Bioabsorbable Regenerative Materials in Vitro
Simain-Sato, Franklin ULg; Lahmouzi, Jamila ULg; Kalykakis, G. K. et al

in Journal of Periodontology (1999), 70(10), 1234-9

BACKGROUND: The use of membranes in guided tissue regeneration (GTR) can limit the apical migration of gingival cells and favor the establishment of new attachment by periodontal ligament fibroblasts ... [more ▼]

BACKGROUND: The use of membranes in guided tissue regeneration (GTR) can limit the apical migration of gingival cells and favor the establishment of new attachment by periodontal ligament fibroblasts. However, gingival recession during healing following GTR has been described as a frequent complication. The purpose of this study was to determine if gingival fibroblasts are affected by the composition of the bioabsorbable membranes used in mucogingival surgery. METHODS: Two type of bioabsorbable regenerative materials were used as cell carriers. Wistar rat gingival fibroblasts (RGF) were obtained from attached gingiva, cut into small fragments, and placed in culture dishes. When confluent, cells were detached using trypsin and identified as "first transferred cells" (P1). At the third passage (P3), cell count, trypan blue exclusion test, acid phosphatase activity, DNA synthesis, phase contrast microscopy, and scanning electron microscopy were performed. The cells were then placed in wells containing the membranes and incubated for 72 hours. RESULTS: When examined under microscopy, the control wells (without membranes) showed one cell type with the elongated appearance characteristic of fibroblasts. The wells with membranes showed an altered cell morphology with a high proportion of cell fragments regardless of the type of membrane used. CONCLUSIONS: These results suggest that cell carrier membranes could affect RGF morphology and thus alter gingival tissue healing following GTR. [less ▲]

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See detailLe syndrome de tension prémenstruelle ou dysphorie prémenstruelle
Legros, S.; Foidart, Jean-Michel ULg; Gaspard, Ulysse ULg et al

in Revue Médicale de Liège (1999), 54(4), 268-73

Premenstrual Tension Syndrome (PMS) has always existed: it has been first described by an endocrinologist from New York in 1931. It is responsible for significant and psychological disorders which justify ... [more ▼]

Premenstrual Tension Syndrome (PMS) has always existed: it has been first described by an endocrinologist from New York in 1931. It is responsible for significant and psychological disorders which justify the study of its pathogenesis. Hormonal dysfunction has been demonstrated among women who are at risk for PMS; nevertheless, it has been shown that neurological transducers are also affected, such as GABAergic, serotoninergic and endorphinic systems. Interactions between the two systems allow to raise the hypothesis of an inbalance between GABAergic and progesterone derived neurosteroids in a psychoneuroendocrinological model. Based on this hypothesis, psychological symptoms can be efficiently treated by anxiolytic or antidepressant treatment. On the other hand, progesterone derivatives and, sometimes, diuretics, are useful on physical symptoms. As far as we know there is so far no single treatment of demonstrated efficacy in the PMS. [less ▲]

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See detailCharacterization of menin from leucocytes of normal and men-1 affected individuals
Poncin, Jacques ULg; Closset, Jean ULg; Legros, Jean-Jacques ULg et al

in 81st Annual Meeting of the Endocrine society - Abstract book (1999)

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See detailDe nouveaux acteurs dans la physiopathologie du metabolisme de l'eau: les aquaporines
Pequeux, Christel ULg; Brilot, Fabienne; Martens, Henri ULg et al

in Revue Médicale de Liège (1999), 54(11), 867-74

Aquaporins are transmembrane proteins mediating water transport across plasma membrane of animal, vegetal or bacterial cells. Among the ten aquaporins known in mammals, six are located in kidney and take ... [more ▼]

Aquaporins are transmembrane proteins mediating water transport across plasma membrane of animal, vegetal or bacterial cells. Among the ten aquaporins known in mammals, six are located in kidney and take part in urine concentration. AQP2 is vasopressin regulated, it is the only family member to be implicated in human pathology, such as nephrogenic diabetes insipidus, congestive heart failure, hepatic cirrhosis, nephrotic syndrome or SIADH. Aquaporins are expressed in a wide variety of tissues, such as brain or gastrointestinal tractus, and suggest a role in water tissue exchange, but their real function is still not define. To know the physiological impact of aquaporins, AQP1, AQP3, AQP4 and AQP5 knockout mice have been created and their phenotype analysed. [less ▲]

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See detailGraft of autologous fibroblasts in gingival tissue in vivo after culture in vitro. Preliminary study on rats.
Simain-Sato, Franklin ULg; Lahmouzi, Jamila ULg; Heinen, Ernst ULg et al

in Journal of Periodontal Research (1999), 34(6), 323-8

Several grafting techniques and guided tissue regeneration techniques (GTR) have been well-developed in periodontal surgery. However, these techniques could induce pain and side effects, such as a ... [more ▼]

Several grafting techniques and guided tissue regeneration techniques (GTR) have been well-developed in periodontal surgery. However, these techniques could induce pain and side effects, such as a gingival recession during the healing period following the therapy. The graft of a small autologous connective tissue, using non-invasive surgical techniques could yield several benefits for the patients. Our preliminary study explores the feasibility of collecting healthy gingival tissues, culturing them in vitro to amplify rat gingival fibroblasts (RGF) and inoculating the obtained cells into autologous rat gingival tissues in vivo. Gingival tissues samples were cultured as explants as described by Freshney et al. and Adolphe. Confluent cells surrounding explants were detached after 7 d of culture from Petri dishes using 0.05% trypsin and designated "first transferred cells" (T1). At the third passage (T3), cells cultured as monolayer were either examined under microscopy--phase contrast, scanning, or transmission electron--or numerated after trypan blue exclusion test. Autologous RGF labelled with fluorochrome were inoculated at the vestibular and palatine site of gingival tissue close to the superior incisors. In this preliminary study, 12 Wistar rats were used; for each, 2 biopsies were dissected and fixed for phase contrast or fluorescence microscopy. On d 1, 3 and 7 after injection in rat gingival tissues, fluorochrome-labelled cells could be detected in all these. [less ▲]

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See detailLa vasopressine, mais pas l'ocytocinen ni le CRF, est impliquée dans la réponse du cortisol aux stress pschologiques, chez des humains sains mais anxieux
Boudare, M; Pequeux, Christel ULg; Hagelstein, Marie-Thérèse ULg et al

in Annales d'Endocrinologie (1999), 60(4), 360

Le but général de cette étude est d'évaluer la réponse au stress, à la fois sous un angle psychologique et biologique, afin d'établir l'éventuel lien qui pourrait être observé entre ces deux paramètres.

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See detailMutation analysis of the MEN1 gene in Belgian patients with multiple endocrine neoplasia type 1 and related diseases.
Poncin, Jacques ULg; Abs, R.; Velkeniers, B. et al

in Human Mutation (1999), 13(1), 54-60

Multiple endocrine neoplasia type 1 (MEN1) is an autosomal dominant disorder characterized by tumors in parathyroids, enteropancreatic endocrine tissues, anterior pituitary, and other tissues. The gene ... [more ▼]

Multiple endocrine neoplasia type 1 (MEN1) is an autosomal dominant disorder characterized by tumors in parathyroids, enteropancreatic endocrine tissues, anterior pituitary, and other tissues. The gene for MEN1 has recently been cloned and shown to code for a 610-amino acid protein of enigmatic function which probably acts as a tumor suppressor. Several mutations causing the MEN1 phenotype have been recently identified. In order to determine the spectrum of MEN1 gene mutations in a sample of 25 Belgian patients, we have systematically screened the 10 exons and adjacent sequences of the MEN1 gene by means of an automatic sequencing protocol. Twelve different mutations were identified including nonsense, frameshift, splicing, and missense mutations. Two of these mutations (D172Y and 357del4) occurred more than once. A missense mutation was also found in a kindred with familial hyperparathyroidism. We observed no significant correlation between the nature or position of mutation and the clinical status. We have also detected 6 intragenic polymorphisms and DNA sequence variants and have analyzed their frequencies in our population. [less ▲]

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See detailMutation analysis of the MEN1 gene in Belgian patients with multiple endocrine neoplasia type I and related diseases
Poncin, Jacques ULg; Abs, R.; Velkeniers, B. et al

in IV european Congress of Endocrinology - Abstract book (1998)

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See detailHemodynamic changes induced by laparoscopy and their endocrine correlates: effects of clonidine.
Joris, Jean ULg; Chiche, Jean-Daniel; Canivet, Jean-Luc ULg et al

in Journal of the American College of Cardiology (1998), 32(5), 1389-96

OBJECTIVES: We investigated endocrine correlates of the hemodynamic changes induced by carbon dioxide pneumoperitoneum (PNO). We then studied whether clonidine might modulate the hemodynamic changes ... [more ▼]

OBJECTIVES: We investigated endocrine correlates of the hemodynamic changes induced by carbon dioxide pneumoperitoneum (PNO). We then studied whether clonidine might modulate the hemodynamic changes induced by PNO by reducing release of catecholamines and vasopressin. BACKGROUND: Both mechanical and neurohumoral factors contribute to the hemodynamic changes induced by carbon dioxide PNO. Several mediators have been proposed, but no study has correlated hemodynamic changes with changes in levels of these potential mediators. METHODS: We conducted two studies, each including 20 healthy patients scheduled for elective laparoscopic cholecystectomy. In the first study serial measurements of hemodynamics (thermodilution technique) were done during laparoscopy and after exsufflation. Plasma concentrations of cortisol, catecholamines, vasopressin, renin, endothelin and prostaglandins were measured at the same time points. In the second study patients were randomly allocated to receive 8 microg/kg clonidine infused over 1 h or placebo before PNO. Hemodynamics and plasma levels of cortisol, catecholamines and vasopressin were measured during PNO and after exsufflation. RESULTS: Peritoneal insufflation resulted in a significant reduction of cardiac output (18+/-4%) and increases in mean arterial pressure (39+/-8%) and systemic (70+/-12%) and pulmonary (98+/-18%) vascular resistances. Laparoscopy resulted in progressive and significant increases in plasma concentrations of cortisol, epinephrine, norepinephrine and renin. Vasopressin plasma concentrations markedly increased immediately after the beginning of PNO (before PNO 6+/-4 pg/ml; during PNO 129+/-42 pg/ml; p < 0.05). The profile of vasopressin release paralleled the time course of changes in systemic vascular resistance. Prostaglandins and endothelin did not change significantly. Clonidine significantly reduced mean arterial pressure, heart rate and the increase in systemic vascular resistance. Clonidine also significantly reduced catecholamine concentrations but did not alter vasopressin and cortisol plasma concentrations. CONCLUSIONS: Vasopressin and catecholamines probably mediate the increase in systemic vascular resistance observed during PNO. Clonidine before PNO reduces catecholamine release and attenuates hemodynamic changes during laparoscopy. [less ▲]

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See detailMutation analysis of the MEN1 gene in Belgian patients with multiple endocrine neoplasia type I and related diseases
Poncin, Jacques ULg; Abs, R.; Velkeniers, B. et al

in 5th Euroregional Oncology meeting - abstract book (1998)

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