... Pierre Parot a , Jean Thiery b and André Verméglio a. ... 195-229, Academic Press, New York 2 Parson, WW, Schenck, CC, Blankenship, RE, Holten, D., Windsor, MW and Shank, CV (1978) in Frontiers of Biological Energetics, Vol. I, pp. ...
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In sheep, phytoestrogens are known to act at various levels on the hypothalamo–pituitary–gonadal axis, as well as the hypothalamo–pituitary–thyroid axis. The levels of genistein and daidzein and their metabolites, p-ethylphenol and equol,... more
In sheep, phytoestrogens are known to act at various levels on the hypothalamo–pituitary–gonadal axis, as well as the hypothalamo–pituitary–thyroid axis. The levels of genistein and daidzein and their metabolites, p-ethylphenol and equol, in the cerebrospinal fluid (CSF) were studied in ewes fed red clover silage. Moreover, to test the hypothesis that phytoestrogens may affect the access of thyroid hormones in
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There is increasing statistical evidence that the presence of tumour cells in bone marrow detected by immunocytochemistry represents an important prognostic indicator in breast cancer, but their individual capacity to become clinical... more
There is increasing statistical evidence that the presence of tumour cells in bone marrow detected by immunocytochemistry represents an important prognostic indicator in breast cancer, but their individual capacity to become clinical metastases is unknown. The aim of this study was to assess the proliferative capacity of these occult metastatic cells in the bone marrow of patients with various stages
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Discrepancies have been reported between HER2 status in primary breast cancer and micrometastatic cells in bone marrow. The aim of this study was to assess HER2 gene status in micrometastatic cells in bone marrow and corresponding primary... more
Discrepancies have been reported between HER2 status in primary breast cancer and micrometastatic cells in bone marrow. The aim of this study was to assess HER2 gene status in micrometastatic cells in bone marrow and corresponding primary tumour. Micrometastatic cells were detected in bone marrow aspirations in a prospective series of 27 breast cancer patients by immunocytochemistry (pancytokeratin antibody). HER2 status of micrometastatic cells was assessed by fluorescence in situ hybridisation (FISH), respectively in 24 out of 27. Primary tumour HER2 status was assessed by immunohistochemistry (CB11 antibody) and by FISH in 20 out of 27 of the cases. HER2 was amplified or overexpressed in five out of 27 (18.5%) primary tumours and in four out of 27 (15%) micrometastatic cells. In two cases, HER2 was overexpressed and amplified in primary tumour, but not in micrometastatic cells, whereas, in one case, HER2 presented a low amplification rate (six copies) in micrometastatic cells not...
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An experiment was designed to determine whether the pars tuberalis is the site of action of melatonin involved in the photoperiodic control of LH and prolactin secretion in sheep. In an attempt to produce a... more
An experiment was designed to determine whether the pars tuberalis is the site of action of melatonin involved in the photoperiodic control of LH and prolactin secretion in sheep. In an attempt to produce a 'short-day' effect on these hormones (i.e. stimulation of LH secretion and inhibition of prolactin release), microimplants of melatonin were placed either around the pituitary stalk (n = 6) or in the third ventricle (n = 5) as a control for the efficacy of the microimplant. Two sham-operated groups were treated with empty microimplants around the pituitary stalk (n = 4) or in the third ventricle (n = 3). A further two control groups were given either no melatonin (n = 5) or a melatonin implant s.c. (n = 6). Administration of a melatonin implant s.c. is known to stimulate LH secretion and inhibit prolactin release in photoperiodically inhibited ewes. During the experiment (over 75 days), there was no significant increase in LH concentrations for the ewes receiving melatonin around the pituitary stalk. A similar lack of response was noted in the untreated or sham-treated ewes. In contrast, LH concentrations increased in ewes treated with the melatonin microimplant in the third ventricle on day 37 (+/- 4) and remained high until day 62 (+/- 4). Similarly, in the ewes given an implant s.c., LH concentrations rose on day 39 (+/- 4) and remained high until the end of the study. Furthermore, melatonin caused an inhibition of prolactin secretion relative to controls only when delivered to these sites (i.e. s.c. and into the third ventricle, but not around the pituitary stalk).(ABSTRACT TRUNCATED AT 250 WORDS)
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Annual variations in day length are responsible for seasonal changes in reproductive activity in sheep. However, in constant photoperiodic conditions, ewes express an endogenous rhythm characterized by alternations of reproductive... more
Annual variations in day length are responsible for seasonal changes in reproductive activity in sheep. However, in constant photoperiodic conditions, ewes express an endogenous rhythm characterized by alternations of reproductive activity and quiescence that are not synchronized among animals. Thus, the main role of photoperiod in the natural environment appears to be the synchronization of this endogenous rhythm. Photoperiodic information is processed through a complex nervous and endocrine pathway to modulate reproductive activity. Light information perceived at the level of the retina is transformed through neural processing into an endocrine signal by the pineal gland: the nocturnal increase in melatonin release. Recent studies strongly suggest that melatonin has a hypothalamic target to modulate the reproductive neuroendocrine axis. Most LHRH perikarya are located in the preoptic area, but this region is devoid of melatonin receptors, and microimplants of melatonin placed in the preoptic area do not effect LHRH release. Thus, melatonin influences LHRH neurones indirectly and must involve interneurons. Good evidence now exists to demonstrate that a population of dopaminergic neurons with axons projecting to the median eminence is one of these interneurons.
Research Interests: Cognitive Science, Reproduction, Dopamine, Melatonin, Brain, and 18 moreProlactin, Sheep, Darkness, Circadian Rhythm, Female, Animals, Retina, Light, Neurons, Natural Environment, Gonadotropin Releasing Hormone, Photoperiod, Pineal Gland, Seasons, Preoptic Area, Neurosciences, Seasonal change, and Median Eminence
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A recent paper reports that circulating tumor cells (CTCs) from metastatic breast cancer patients exhibit heterogeneous epithelial and mesenchymal phenotypes and that CTCs display higher frequencies of partial or full-blown mesenchymal... more
A recent paper reports that circulating tumor cells (CTCs) from metastatic breast cancer patients exhibit heterogeneous epithelial and mesenchymal phenotypes and that CTCs display higher frequencies of partial or full-blown mesenchymal phenotype than carcinoma cells within primary tumors. Mesenchymal-like CTCs are also elevated in patients who are refractory to therapy.
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The epithelial-to-mesenchymal transition (EMT), a key process in morphogenesis, is often driven by repressing expression of adherens junction components, such as E-cadherin. In this issue of Developmental Cell, Campbell et al. (2011)... more
The epithelial-to-mesenchymal transition (EMT), a key process in morphogenesis, is often driven by repressing expression of adherens junction components, such as E-cadherin. In this issue of Developmental Cell, Campbell et al. (2011) uncover an alternative mechanism in the Drosophila embryonic gut that promotes EMT via Serpent, a GATA transcriptional repressor of the apicobasal polarity gene crumbs.
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Interactions between cells and extracellular matrix play a crucial role during development by controlling tissue remodelling and cell migration. Integrins are the main family of cell surface receptors for extracellular matrix. The... more
Interactions between cells and extracellular matrix play a crucial role during development by controlling tissue remodelling and cell migration. Integrins are the main family of cell surface receptors for extracellular matrix. The knockout of integrin genes in mouse embryos has provided new insights into the function of these receptors during embryonic development and morphogenesis. The lethality observed either during embryonic life or after birth suggests that many integrins are essential.
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Interactions of cells with the extracellular matrix are essential for the control of tissue remodelling, cell migration, and embryogenesis. At the cell-extracellular matrix contact points, specialized structures are formed and termed... more
Interactions of cells with the extracellular matrix are essential for the control of tissue remodelling, cell migration, and embryogenesis. At the cell-extracellular matrix contact points, specialized structures are formed and termed focal adhesions, where transmembrane adhesion receptors provide a structural link between the actin cytoskeleton and the extracellular matrix components. Numerous structural and regulatory proteins assemble at the cytoplasmic face of focal adhesions in a Rho-dependent fashion.
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ABSTRACT We present a new curve skeleton model designed for surface modeling and processing. This skeleton is defined as the geometrical integration of a piecewise harmonic parameterization defined over a disk-cylinder surface... more
ABSTRACT We present a new curve skeleton model designed for surface modeling and processing. This skeleton is defined as the geometrical integration of a piecewise harmonic parameterization defined over a disk-cylinder surface decomposition. This decomposition is computed using a progressive Region Graph reduction based on both geometric and topological criteria which can be iteratively optimized to improve region boundaries. The skeleton has an analytical form with regularity inherited from the surface one. Such a form offers well-defined surface-skeleton and skeleton-surface projections. The resulting skeleton satisfies quality criteria which are relevant for skeleton-based modeling and processing. We propose applications that benefit from our skeleton model, including local thickness editing, inset surface creation for shell mapping, as well as a new mid-scale feature preserving smoothing. © 2012 Wiley Periodicals, Inc.
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Sheep in temperate latitudes are seasonal breeders. Of the different seasonal cues, photoperiod is the most reliable parameter and is used by animals as an indication of the time of the year to synchronize endogenous annual rhythms of... more
Sheep in temperate latitudes are seasonal breeders. Of the different seasonal cues, photoperiod is the most reliable parameter and is used by animals as an indication of the time of the year to synchronize endogenous annual rhythms of reproduction and physiology. The photoperiodic information is transduced into neuroendocrine changes through variations in melatonin secretion from the pineal gland. Melatonin triggers
Research Interests: Reproduction, Animal Production, Dopamine, Melatonin, Seasonality, and 15 moreProlactin, Animals, Negative Feedback, Food intake, Body Mass, Gonadotropin Releasing Hormone, Photoperiod, Pineal Gland, Veterinary Sciences, Seasons, Long Day Care, Luteinizing Hormone, Seasonal change, Estradiol, and Follicle stimulating hormone
Many mammalian species from temperate latitudes exhibit seasonal variations in breeding activity which are controlled by the annual photoperiodic cycle. Photoperiodic information is conveyed through several neural relays from the retina... more
Many mammalian species from temperate latitudes exhibit seasonal variations in breeding activity which are controlled by the annual photoperiodic cycle. Photoperiodic information is conveyed through several neural relays from the retina to the pineal gland where the light signal is translated into a daily cycle of melatonin secretion: high at night, low in the day. The length of the nocturnal secretion of melatonin reflects the duration of the night and it regulates the pulsatile secretion of gonadotropin-releasing hormone (GnRH) from the hypothalamus. Changes in GnRH release induce corresponding changes in luteinising hormone secretion which are responsible for the alternating presence or absence of ovulation in the female, and varying sperm production in the male. It is not yet known where and how this pineal indoleamine acts to exert this effect. Although melatonin binding sites are preferentially localised in the pars tuberalis (PT) of the adenohypophysis, the hypothalamus contains the physiological target sites of melatonin for its action on reproduction. Melatonin does not seem to act directly on GnRH neurons; rather it appears to involve a complex neural circuit of interneurons that includes at least dopaminergic, serotoninergic and excitatory aminoacidergic neurons.
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Giving a subcutaneous oestradiol implant during anoestrus to ovariectomized ewes inhibits pulsatile LH secretion. This effect results from an increased negative feedback of oestradiol and depends on the synthesis of biogenic amines,... more
Giving a subcutaneous oestradiol implant during anoestrus to ovariectomized ewes inhibits pulsatile LH secretion. This effect results from an increased negative feedback of oestradiol and depends on the synthesis of biogenic amines, mainly from the mediobasal hypothalamus. In the present study, we examined the effect of oestradiol on the extracellular levels of amines and their metabolites. Eight ewes were sampled by microdialysis from the lateral retrochiasmatic area, including the dopaminergic A15 nucleus, during inhibition of LH secretion by long days. Two dialysis sessions were carried out on each ewe; one after a 10-day oestradiol treatment and the other one after 10 days without oestradiol treatment. Half of the ewes were first oestradiol-treated then untreated, the other half received the treatment in the reverse order. Oestradiol caused a decline in pulsatile LH secretion without affecting the secretion of prolactin. This steroid also led to a significant increase in the levels of amine metabolites: 3,4-dihydroxyphenylacetic acid, homovanillic acid and 5-hydroxyindoleacetic acid in the extracellular medium. These results demonstrate the effect of oestradiol on aminergic activity as related to changes in hormonal secretions during long days (16 h of light per 24 h). Thus our data support the hypothesis that amines inhibit gonadotrophic secretion during anoestrus in the ewe and suggest that there is an activation of the aminergic neurones from the retrochiasmatic area in this regulatory mechanism.
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In the ewe, the inhibition of pulsatile LH secretion by oestradiol during long days depends on dopaminergic activity and could involve amino acid transmitters. In the first experiment of the present study we observed the changes in LH... more
In the ewe, the inhibition of pulsatile LH secretion by oestradiol during long days depends on dopaminergic activity and could involve amino acid transmitters. In the first experiment of the present study we observed the changes in LH secretion in ovariectomised ewes under long days immediately after subcutaneous implantation of oestradiol (peripheral treatment). In the second experiment, in order to identify the site of action of oestradiol, we observed the LH changes following intracerebral infusion of oestradiol through a microdialysis membrane (central treatment) within the preoptic area, the mediobasal hypothalamus (MBH) or the retrochiasmatic area (RCh) and measured amino acids and catecholaminergic transmitters and metabolites within the dialysates. With peripheral treatment, the amplitude, the nadir and the area under the LH pulse curve decreased within 4 to 8 h of the insertion of a subcutaneous oestradiol implant. After 18 h, the amplitude and the area under the pulses increased, as well as the intervals between pulses (from 49.9 + 1.4 min to 75.6 +/- 5.9 min). With central oestradiol treatment. LH changes were similar whatever the site of oestradiol infusion, suggesting either multiple sites of action or diffusion between structures. Twenty hours after the beginning of intracerebral oestradiol treatment, the amplitude and the area under the pulses increased, as did the interval between LH pulses (from 49.5 +/- 4.1 min to 73.2 +/- 14.2 min). Comparison of peripheral with central oestradiol treatment suggested that the long-lasting decrease in the nadir, as well as the transitory decrease in the amplitude and area, before 18 h in experiment 1 are reflections of hypophysial effects. In contrast, the increases in amplitude and area under the LH pulse curve seen 18-20 h after oestradiol in the two experiments could be due to the higher amplitude of LHRH pulses, as a result of an early stimulatory effect of oestradiol. After central oestradiol infusion, there was a decline in the concentration in the dialysate of two metabolites of dopamine, 3,4-dihydroxyphenylacetic acid and homovanillic acid in the RCh, suggesting an early inhibition of monoamine oxidase by the steroid. During the inhibition of LH pulsatility the concentration of gamma-aminobutyric acid in the dialysate from the RCh and the MBH increased, suggesting the participation of this transmitter in the changes induced by oestradiol under long days.
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Neural structures containing luteinizing hormone-releasing hormone (LHRH) are characterized in adult ewe and female lamb brains. Three anti-LHRH antisera are used in an immunofluorescent or immunoperoxidase method. On our preparations,... more
Neural structures containing luteinizing hormone-releasing hormone (LHRH) are characterized in adult ewe and female lamb brains. Three anti-LHRH antisera are used in an immunofluorescent or immunoperoxidase method. On our preparations, all three gave the same results, expressed as number of labelled cells (about 2500 in a whole brain). It was found that 95% of the LHRH-immunoreactive cells are located in the preoptico-hypothalamic area, where cell bodies are localized mainly (50%) in the area surrounding the organum vasculosum of the lamina terminalis (OVLT); they are also found in a more anterior section of the medial part of the olfactory tubercle and the medial septum (14%), in a more posterior situation in the anterior and lateral hypothalamus (16%), and in the mediobasal hypothalamus (15%). Fibres originating in various part of the whole preoptico-hypothalamic group reach the OVLT and the median eminence. The remaining cells (5%) and fibres are found in various tel-, di-, and mesencephalic areas.
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The composition of the 3'terminal, 5'terminal and 5'penultimate nucleotides of the oligonucleotides released by spleen acid DNase and snail acid DNase from five ;repetitive' DNAs (guinea pig, mouse and crab... more
The composition of the 3'terminal, 5'terminal and 5'penultimate nucleotides of the oligonucleotides released by spleen acid DNase and snail acid DNase from five ;repetitive' DNAs (guinea pig, mouse and crab satellite DNAs, yeast mitochondrial DNA and poly (dAT:dAT)) and four ;eukaryotic' DNAs (calf thymus, guinea pig and mouse liver DNAs, and yeast nuclear DNA) have been investigated and found to deviate in characteristic ways from those expected for bacterial DNAs having comparable base compositions. The deviation patterns obtained represent a novel way of characterizing and comparing different DNAs on the basis of the frequency of the nucleotide sequences they contain.
Research Interests: Mathematics, Kinetics, Biological Sciences, DNA, Spleen, and 15 moreMethods, Environmental Sciences, Escherichia coli, Mice, Animals, Nucleic Acids, Snails, Cattle, Species Specificity, Base Sequence, Snake bites, Micrococcus luteus, Oligonucleotides, Biochemistry and cell biology, and Haemophilus influenzae
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... Frequent activating mutations of FGFR3 in human bladder and cervix carcinomas. David Cappellen , Catherine De Oliveira , David Ricol , Sixtina de Medina , J|[eacute]|r|[ocirc]|me Bourdin ,Xavier Sastre-Garau , Dominique Chopin , Jean... more
... Frequent activating mutations of FGFR3 in human bladder and cervix carcinomas. David Cappellen , Catherine De Oliveira , David Ricol , Sixtina de Medina , J|[eacute]|r|[ocirc]|me Bourdin ,Xavier Sastre-Garau , Dominique Chopin , Jean Paul Thiery & Fran|[ccedil]|ois Radvanyi. ...
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After initial regression in response to androgen deprivation, most prostate cancers develop resistance to endocrine therapy. Identification of cellular and molecular changes occurring during endocrine therapy-induced regression and... more
After initial regression in response to androgen deprivation, most prostate cancers develop resistance to endocrine therapy. Identification of cellular and molecular changes occurring during endocrine therapy-induced regression and subsequent hormone insensitivity may point to mechanisms underlying the transition to hormone-independent prostate cancer. A series of untreated (n = 24), regressed (n = 15), and endocrine therapy-resistant (n = 10) prostatic adenocarcinomas were analyzed using immunohistochemistry with regard to cytokeratin 5 and 18, androgen receptor (AR), and epidermal growth factor receptor (EGF-R) expression in tumor cells. Using semiquantitative reverse transcription-polymerase chain reaction, the amount of AR mRNA also was determined. In regressed and therapy-resistant prostate cancers, an increase in cytokeratin 5-positive tumor cells was noted when compared with untreated carcinomas. Similarly, the proportion of EGF-R-positive tumor cells increased in the treated cases, whereas the proportion of AR-positive tumor cells dropped in regressed carcinomas and increased in hormone-refractory cancers. In the latter group, an eightfold higher level of AR mRNA was observed when compared with the other cases. Changes in the proportion of cytokeratin 5 and EGF-R-positive tumor cells suggests that during androgen deprivation an enlarged subpopulation of tumor cells with combined features of basal and secretory phenotypes arises. The increased proportion of AR-positive tumor cells during the transition from the regression phase to the hormone escape phase points to an important role of AR overexpression in this process.