The Experts below are selected from a list of 159 Experts worldwide ranked by ideXlab platform
Morten Moller - One of the best experts on this subject based on the ideXlab platform.
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Origin of cerebrospinal fluid melatonin and possible function in the integration of photoperiod.
Reproduction (Cambridge England) Supplement, 2020Co-Authors: Tricoire H, P Chemineau, Morten Moller, Benoit MalpauxAbstract:Abstract Melatonin, which is synthesized at night by the Pineal gland, is present in the cerebrospinal fluid (CSF), but its entry site and its role in this compartment are not known. Using several approaches, we tested the hypothesis that melatonin enters the CSF through the Pineal Recess, an evagination of the third ventricle. CSF melatonin concentrations are higher near the Pineal gland than in the anterior part of the third ventricle, and decrease markedly (80%) after sealing off the Pineal Recess. Moreover, ultrastructure and permeability analyses of the Pineal-CSF interface showed that melatonin could reach the CSF either via delivery in situ by protruding Pinealocytes that make direct contact with the CSF or via extracellular secretion and interstitial fluid draining into the ventricular lumen. These data indicate that melatonin in the CSF probably originates from a few Pinealocytes of the basal part of the Pineal gland neighbouring the Pineal Recess. Melatonin carried to the brain by the blood appears to be able to mediate the effects of photoperiod on reproduction, but it is unclear whether melatonin in CSF may fine-tune this response both in terms of timing and amplitude. It is critical to determine which pathway, blood or CSF, allows melatonin to reach its central targets more efficiently.
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cellular lining of the sheep Pineal Recess studied by light transmission and scanning electron microscopy morphologic indications for a direct secretion of melatonin from the Pineal gland to the cerebrospinal fluid
The Journal of Comparative Neurology, 2003Co-Authors: H Tricoire, Benoit Malpaux, Morten MollerAbstract:In the sheep, the Pineal hormone melatonin displays nocturnal levels 20 times as high in the cerebrospinal fluid of the third ventricle as in the jugular blood. Moreover, in the Pineal Recess, the evagination of the third ventricle into the Pineal stalk, the levels of melatonin in the cerebrospinal fluid are even higher than in the ventral part of the third ventricle. This finding suggests melatonin to be secreted directly from the Pineal gland to the ventricular lumen of the Pineal Recess of this species. We have, therefore, studied the interface between the sheep Pineal gland and the cerebrospinal fluid by light-, scanning-, and electron microscopy of the Pineal Recess, as well as the permeability of the interface by tracer injections into the third ventricle. First, we show that the classic ependymal lining of the third ventricle disappears in the superior part of the Recess. In this area, bulging Pinealocytes, displaying immunoreactivity for serotonin, directly appose the cerebrospinal fluid. This Pineal– cerebrospinal fluid interface of the sheep is large compared with other species, especially rodent species. Intraventricular injections of horseradish peroxidase and fluorescein isothiocyanate showed that both these tracers could permeate from the Pineal Recess into the sheep Pineal parenchyma. This permeation was due to the presence of gap and intermediate junctions connecting the Pinealocytes apposing the ventricular lumen. Thus, our results show that endocrine cells in this specialized area of the ventricular system are in direct contact with the cerebrospinal fluid. This finding supports the physiological concept of a direct secretion of melatonin into the cerebrospinal fluid of the sheep Pineal Recess. J. Comp. Neurol. 456:39 – 47, 2003. © 2002 Wiley-Liss, Inc. Indexing terms: ependyma; Pinealocytes; junctions; horseradish peroxidase; tracers
L Guibaud - One of the best experts on this subject based on the ideXlab platform.
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dilatation of the supra Pineal Recess on prenatal imaging early clue for obstructive ventriculomegaly downstream of the third ventricle
Prenatal Diagnosis, 2014Co-Authors: Caroline Azzi, Mariebrune Giaconia, Audrey Lacalm, Mona Massoud, P Gaucherand, L GuibaudAbstract:Objective The objective of this article is to describe the diagnostic significance of prenatal identification of dilated supra-Pineal Recess (SPR) in cases of ventriculomegaly. Method A retrospective study, based on neurosonography and magnetic resonance imaging, of a series of five prenatal cases referred to our institution because of ventriculomegaly associated with dilatation of the SPR. Results Ventriculomegaly of obstructive origin was diagnosed in all cases and related to obstruction downstream of the third ventricle. The diagnosis in the five prenatal cases, confirmed on early post-natal imaging, included the following: malformative aqueductal stenosis, ischemic–haemorrhagic parenchymal supra-tentorial insult complicated by aqueductal stenosis, Blake's pouch cyst, cystic lesion of the posterior fossa and sub-ependymal haemorrhage and Dandy–Walker malformation. In all cases, the third ventricle was prominent and associated with a dilated SPR. In two cases, the dilatation of the SPR was an early clue to e obstructive ventriculomegaly, which was initially minor and became severe on follow-up imaging. Conclusion The presence of a dilated SPR prenatally in the presence of even mild ventriculomegaly should prompt evaluation and follow-up for the presence of obstructive ventriculomegaly with obstruction located downstream of the third ventricle. © 2014 John Wiley & Sons, Ltd.
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Dilatation of the supra‐Pineal Recess on prenatal imaging: early clue for obstructive ventriculomegaly downstream of the third ventricle
Prenatal Diagnosis, 2014Co-Authors: Caroline Azzi, Mariebrune Giaconia, Audrey Lacalm, Mona Massoud, P Gaucherand, L GuibaudAbstract:Objective The objective of this article is to describe the diagnostic significance of prenatal identification of dilated supra-Pineal Recess (SPR) in cases of ventriculomegaly. Method A retrospective study, based on neurosonography and magnetic resonance imaging, of a series of five prenatal cases referred to our institution because of ventriculomegaly associated with dilatation of the SPR. Results Ventriculomegaly of obstructive origin was diagnosed in all cases and related to obstruction downstream of the third ventricle. The diagnosis in the five prenatal cases, confirmed on early post-natal imaging, included the following: malformative aqueductal stenosis, ischemic–haemorrhagic parenchymal supra-tentorial insult complicated by aqueductal stenosis, Blake's pouch cyst, cystic lesion of the posterior fossa and sub-ependymal haemorrhage and Dandy–Walker malformation. In all cases, the third ventricle was prominent and associated with a dilated SPR. In two cases, the dilatation of the SPR was an early clue to e obstructive ventriculomegaly, which was initially minor and became severe on follow-up imaging. Conclusion The presence of a dilated SPR prenatally in the presence of even mild ventriculomegaly should prompt evaluation and follow-up for the presence of obstructive ventriculomegaly with obstruction located downstream of the third ventricle. © 2014 John Wiley & Sons, Ltd.
Benoit Malpaux - One of the best experts on this subject based on the ideXlab platform.
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Origin of cerebrospinal fluid melatonin and possible function in the integration of photoperiod.
Reproduction (Cambridge England) Supplement, 2020Co-Authors: Tricoire H, P Chemineau, Morten Moller, Benoit MalpauxAbstract:Abstract Melatonin, which is synthesized at night by the Pineal gland, is present in the cerebrospinal fluid (CSF), but its entry site and its role in this compartment are not known. Using several approaches, we tested the hypothesis that melatonin enters the CSF through the Pineal Recess, an evagination of the third ventricle. CSF melatonin concentrations are higher near the Pineal gland than in the anterior part of the third ventricle, and decrease markedly (80%) after sealing off the Pineal Recess. Moreover, ultrastructure and permeability analyses of the Pineal-CSF interface showed that melatonin could reach the CSF either via delivery in situ by protruding Pinealocytes that make direct contact with the CSF or via extracellular secretion and interstitial fluid draining into the ventricular lumen. These data indicate that melatonin in the CSF probably originates from a few Pinealocytes of the basal part of the Pineal gland neighbouring the Pineal Recess. Melatonin carried to the brain by the blood appears to be able to mediate the effects of photoperiod on reproduction, but it is unclear whether melatonin in CSF may fine-tune this response both in terms of timing and amplitude. It is critical to determine which pathway, blood or CSF, allows melatonin to reach its central targets more efficiently.
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cellular lining of the sheep Pineal Recess studied by light transmission and scanning electron microscopy morphologic indications for a direct secretion of melatonin from the Pineal gland to the cerebrospinal fluid
The Journal of Comparative Neurology, 2003Co-Authors: H Tricoire, Benoit Malpaux, Morten MollerAbstract:In the sheep, the Pineal hormone melatonin displays nocturnal levels 20 times as high in the cerebrospinal fluid of the third ventricle as in the jugular blood. Moreover, in the Pineal Recess, the evagination of the third ventricle into the Pineal stalk, the levels of melatonin in the cerebrospinal fluid are even higher than in the ventral part of the third ventricle. This finding suggests melatonin to be secreted directly from the Pineal gland to the ventricular lumen of the Pineal Recess of this species. We have, therefore, studied the interface between the sheep Pineal gland and the cerebrospinal fluid by light-, scanning-, and electron microscopy of the Pineal Recess, as well as the permeability of the interface by tracer injections into the third ventricle. First, we show that the classic ependymal lining of the third ventricle disappears in the superior part of the Recess. In this area, bulging Pinealocytes, displaying immunoreactivity for serotonin, directly appose the cerebrospinal fluid. This Pineal– cerebrospinal fluid interface of the sheep is large compared with other species, especially rodent species. Intraventricular injections of horseradish peroxidase and fluorescein isothiocyanate showed that both these tracers could permeate from the Pineal Recess into the sheep Pineal parenchyma. This permeation was due to the presence of gap and intermediate junctions connecting the Pinealocytes apposing the ventricular lumen. Thus, our results show that endocrine cells in this specialized area of the ventricular system are in direct contact with the cerebrospinal fluid. This finding supports the physiological concept of a direct secretion of melatonin into the cerebrospinal fluid of the sheep Pineal Recess. J. Comp. Neurol. 456:39 – 47, 2003. © 2002 Wiley-Liss, Inc. Indexing terms: ependyma; Pinealocytes; junctions; horseradish peroxidase; tracers
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melatonin enters the cerebrospinal fluid through the Pineal Recess
Endocrinology, 2002Co-Authors: Helene Tricoire, A Locatelli, P Chemineau, Benoit MalpauxAbstract:The Pineal Recess (PR), a third ventricle (IIIV) evagination penetrating into the Pineal gland, could constitute a site of melatonin passage to the cerebrospinal fluid (CSF) and explain the high concentrations of melatonin in this fluid. To test this hypothesis, we characterized melatonin distribution in the IIIV of sheep by CSF collection in the ventral part of IIIV (vIIIV) and in PR. At 30 l/min collection rate, melatonin concentrations were much higher in PR than in vIIIV (19,934 6,388 vs. 178 70 pg/ml, mean SEM, respectively, P < 0.005), and they increased in vIIIV when CSF collection stopped in the PR (P < 0.05). At 6 l/min, levels increased to 1,682 585 pg/ml in vIIIV and were not influenced by CSF collection in the PR. This concentration difference between sites and the influence of PR collection on vIIIV levels suggest that melatonin reaches the PR and then diffuses to the IIIV. To confirm the role of PR, we demonstrated that its surgical sealing off decreased IIIV melatonin levels (1,020 305 pg/ml, compared with 5,984 1,706 and 6,917 1,601 pg/ml in shams or animals with a failed sealing off, respectively, P < 0.01) without changes in blood levels. Therefore, this study identified the localization of the main site of penetration of melatonin into the CSF, the Pineal Recess. (Endocrinology 143: 84 –90, 2002)
Caroline Azzi - One of the best experts on this subject based on the ideXlab platform.
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dilatation of the supra Pineal Recess on prenatal imaging early clue for obstructive ventriculomegaly downstream of the third ventricle
Prenatal Diagnosis, 2014Co-Authors: Caroline Azzi, Mariebrune Giaconia, Audrey Lacalm, Mona Massoud, P Gaucherand, L GuibaudAbstract:Objective The objective of this article is to describe the diagnostic significance of prenatal identification of dilated supra-Pineal Recess (SPR) in cases of ventriculomegaly. Method A retrospective study, based on neurosonography and magnetic resonance imaging, of a series of five prenatal cases referred to our institution because of ventriculomegaly associated with dilatation of the SPR. Results Ventriculomegaly of obstructive origin was diagnosed in all cases and related to obstruction downstream of the third ventricle. The diagnosis in the five prenatal cases, confirmed on early post-natal imaging, included the following: malformative aqueductal stenosis, ischemic–haemorrhagic parenchymal supra-tentorial insult complicated by aqueductal stenosis, Blake's pouch cyst, cystic lesion of the posterior fossa and sub-ependymal haemorrhage and Dandy–Walker malformation. In all cases, the third ventricle was prominent and associated with a dilated SPR. In two cases, the dilatation of the SPR was an early clue to e obstructive ventriculomegaly, which was initially minor and became severe on follow-up imaging. Conclusion The presence of a dilated SPR prenatally in the presence of even mild ventriculomegaly should prompt evaluation and follow-up for the presence of obstructive ventriculomegaly with obstruction located downstream of the third ventricle. © 2014 John Wiley & Sons, Ltd.
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Dilatation of the supra‐Pineal Recess on prenatal imaging: early clue for obstructive ventriculomegaly downstream of the third ventricle
Prenatal Diagnosis, 2014Co-Authors: Caroline Azzi, Mariebrune Giaconia, Audrey Lacalm, Mona Massoud, P Gaucherand, L GuibaudAbstract:Objective The objective of this article is to describe the diagnostic significance of prenatal identification of dilated supra-Pineal Recess (SPR) in cases of ventriculomegaly. Method A retrospective study, based on neurosonography and magnetic resonance imaging, of a series of five prenatal cases referred to our institution because of ventriculomegaly associated with dilatation of the SPR. Results Ventriculomegaly of obstructive origin was diagnosed in all cases and related to obstruction downstream of the third ventricle. The diagnosis in the five prenatal cases, confirmed on early post-natal imaging, included the following: malformative aqueductal stenosis, ischemic–haemorrhagic parenchymal supra-tentorial insult complicated by aqueductal stenosis, Blake's pouch cyst, cystic lesion of the posterior fossa and sub-ependymal haemorrhage and Dandy–Walker malformation. In all cases, the third ventricle was prominent and associated with a dilated SPR. In two cases, the dilatation of the SPR was an early clue to e obstructive ventriculomegaly, which was initially minor and became severe on follow-up imaging. Conclusion The presence of a dilated SPR prenatally in the presence of even mild ventriculomegaly should prompt evaluation and follow-up for the presence of obstructive ventriculomegaly with obstruction located downstream of the third ventricle. © 2014 John Wiley & Sons, Ltd.
P Gaucherand - One of the best experts on this subject based on the ideXlab platform.
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dilatation of the supra Pineal Recess on prenatal imaging early clue for obstructive ventriculomegaly downstream of the third ventricle
Prenatal Diagnosis, 2014Co-Authors: Caroline Azzi, Mariebrune Giaconia, Audrey Lacalm, Mona Massoud, P Gaucherand, L GuibaudAbstract:Objective The objective of this article is to describe the diagnostic significance of prenatal identification of dilated supra-Pineal Recess (SPR) in cases of ventriculomegaly. Method A retrospective study, based on neurosonography and magnetic resonance imaging, of a series of five prenatal cases referred to our institution because of ventriculomegaly associated with dilatation of the SPR. Results Ventriculomegaly of obstructive origin was diagnosed in all cases and related to obstruction downstream of the third ventricle. The diagnosis in the five prenatal cases, confirmed on early post-natal imaging, included the following: malformative aqueductal stenosis, ischemic–haemorrhagic parenchymal supra-tentorial insult complicated by aqueductal stenosis, Blake's pouch cyst, cystic lesion of the posterior fossa and sub-ependymal haemorrhage and Dandy–Walker malformation. In all cases, the third ventricle was prominent and associated with a dilated SPR. In two cases, the dilatation of the SPR was an early clue to e obstructive ventriculomegaly, which was initially minor and became severe on follow-up imaging. Conclusion The presence of a dilated SPR prenatally in the presence of even mild ventriculomegaly should prompt evaluation and follow-up for the presence of obstructive ventriculomegaly with obstruction located downstream of the third ventricle. © 2014 John Wiley & Sons, Ltd.
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Dilatation of the supra‐Pineal Recess on prenatal imaging: early clue for obstructive ventriculomegaly downstream of the third ventricle
Prenatal Diagnosis, 2014Co-Authors: Caroline Azzi, Mariebrune Giaconia, Audrey Lacalm, Mona Massoud, P Gaucherand, L GuibaudAbstract:Objective The objective of this article is to describe the diagnostic significance of prenatal identification of dilated supra-Pineal Recess (SPR) in cases of ventriculomegaly. Method A retrospective study, based on neurosonography and magnetic resonance imaging, of a series of five prenatal cases referred to our institution because of ventriculomegaly associated with dilatation of the SPR. Results Ventriculomegaly of obstructive origin was diagnosed in all cases and related to obstruction downstream of the third ventricle. The diagnosis in the five prenatal cases, confirmed on early post-natal imaging, included the following: malformative aqueductal stenosis, ischemic–haemorrhagic parenchymal supra-tentorial insult complicated by aqueductal stenosis, Blake's pouch cyst, cystic lesion of the posterior fossa and sub-ependymal haemorrhage and Dandy–Walker malformation. In all cases, the third ventricle was prominent and associated with a dilated SPR. In two cases, the dilatation of the SPR was an early clue to e obstructive ventriculomegaly, which was initially minor and became severe on follow-up imaging. Conclusion The presence of a dilated SPR prenatally in the presence of even mild ventriculomegaly should prompt evaluation and follow-up for the presence of obstructive ventriculomegaly with obstruction located downstream of the third ventricle. © 2014 John Wiley & Sons, Ltd.