The Role of the Placodes in the Development of the Glossopharyngeal, Vagal, and Trigeminal Ganglia

Neurographics ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 163-181
Author(s):  
P.M. Som
Keyword(s):  
Neural Crest ◽  
Trigeminal Ganglion ◽  
Cranial Nerves ◽  
Present Review ◽  
Trigeminal Ganglia ◽  
Epibranchial Placodes ◽  
Vagal Ganglia

The epibranchial placodes combine with the neural crest to form the inferior and superior ganglia of the glossopharyngeal and vagal cranial nerves, respectively. By comparison, the single trigeminal ganglion is composed of both neural crest and placodal cells. The steps that lead up to these events include gastrulation and the embryology of the notochord, neural crest, and the placodes. Each of these steps is reviewed in some detail. In previous reviews in this series, the embryology related to the olfactory, otic, and lens placodes, and to the geniculate ganglia has been discussed.1-3 However, the somewhat unusual embryology of the 2 ganglia of cranial nerves IX and X was only briefly mentioned as was the development of the trigeminal ganglion.4 This present review revisits these events and specifically focuses on how these ganglia develop.Learning Objective: The reader will learn the unusual development of the superior and inferior glossopharyngeal and the vagal ganglia as well as review the varied steps in the embryology that proceeds these events. By comparison, the development of the single trigeminal ganglion is presented and the differences in its development from that of the ganglia of cranial nerves IX and X are emphasized.

scholarly journals Loss of Elp1 disrupts trigeminal ganglion neurodevelopment in a model of Familial Dysautonomia

2021 ◽  
Author(s):  
Carrie E Leonard ◽  
Frances Lefcort ◽  
Lisa A Taneyhill
Keyword(s):  
Neural Crest ◽  
Trigeminal Ganglion ◽  
Facial Pain ◽  
Familial Dysautonomia ◽  
Trigeminal Ganglia ◽  
Nociceptive Neurons ◽  
Target Innervation ◽  
Trigeminal Neurons ◽  
Complex Protein ◽  
Trigeminal Nerves

Familial Dysautonomia (FD) is a sensory and autonomic neuropathy caused by a mutation in Elongator complex protein 1 (ELP1). FD patients have small trigeminal nerves and impaired perception of facial pain and temperature. These signals are relayed by nociceptive neurons in the trigeminal ganglion, a structure comprised of both neural crest- and placode-derived cells. Mice lacking Elp1 in neural crest derivatives (Elp1 CKO) are born with smaller trigeminal ganglia, suggesting Elp1 is important for trigeminal ganglion development, yet the function of Elp1 in this context is unknown. We demonstrate Elp1 expression in both neural crest- and placode-derived trigeminal neurons, which our data suggest give rise to primarily TrkA- and TrkB/C-expressing neurons, respectively. While Elp1 is not required for initial trigeminal ganglion formation, Elp1 CKO trigeminal neurons exhibit abnormal axon outgrowth and decreased target innervation. Developing nociceptors that express the receptor TrkA are especially vulnerable to Elp1 loss. TrkA expression is decreased in Elp1 CKO trigeminal nerve endings, coinciding with increased cell death. Subsequently, fewer TrkA neurons are present in the Elp1 CKO trigeminal ganglion, indicating Elp1 supports the target innervation and survival of trigeminal nociceptors. These findings explain the loss of facial pain and temperature sensation in FD.

Osteoporosis Entwined with Cardiovascular Disease: The Implication of Osteoprotegerin and Example of Statins

2020 ◽  
Vol 27 ◽  
Author(s):  
Maria V. Deligiorgi ◽  
Mihalis I. Panayiotidis ◽  
Gerasimos Siasos ◽  
Dimitrios T. Trafalis
Keyword(s):  
Cardiovascular Disease ◽  
Physicochemical Characteristics ◽  
Dual Role ◽  
Present Review ◽  
Vascular Cells ◽  
Molecular Fingerprint ◽  
Missing Link ◽  
Epidemiological Factors ◽  
Outstanding Issue

: Beyond being epiphenomenon of shared epidemiological factors, the integration of osteoporosis (OP) with cardiovascular disease (CVD)− termed "calcification paradox"− reflects a continuum of aberrant cardiometabolic status. The present review provides background knowledge on "calcification paradox", focusing on the endocrine aspect of vasculature orchestrated by the osteoblastic molecular fingerprint of vascular cells, acquired via imbalance among established modulators of mineralization. Osteoprotegerin (OPG)–the well-established osteoprotective cytokine−has recently been shown to exert a vessel-modifying role. Prompted by this notion, the present review interrogates OPG as the potential missing link between OP and CVD. However, so far, the confirmation of this hypothesis is hindered by the equivocal role of OPG in CVD, being both proatherosclerotic and antiatherosclerotic. Further research is needed to illuminate whether OPG could be biomarker of the "calcification paradox". Moreover, the present review brings into prominence the dual role of statins−cardioprotective and osteoprotective− as potential illustration of the integration of CVD with OP. Considering that the statins-induced modulation of OPG is central to the statins-driven osteoprotective signalling, statins could be suggested as illustration of the role of OPG in the bone/vessels crosstalk, if further studies consolidate the contribution of OPG to the cardioprotective role of statins. Another outstanding issue that merits further evaluation is the inconsistency of the osteoprotective role of statins. Further understanding of the varying bone-modifying role of statins, likely attributed to the unique profile of different classes of statins defined by distinct physicochemical characteristics, may yield tangible benefits for treating simultaneously OP and CVD.

scholarly journals FDG-PET/CT for the Management of Post-Chemotherapy Residual Mass in Hodgkin lymphoma

Cancers ◽  
2021 ◽  
Vol 13 (16) ◽  
pp. 3952
Author(s):  
Andrea Gallamini ◽  
Michał Kurlapski ◽  
Jan Maciej Zaucha
Keyword(s):  
Treatment Outcome ◽  
Hodgkin Lymphoma ◽  
Fdg Pet ◽  
Quantitative Methods ◽  
Present Review ◽  
Response To Treatment ◽  
Published Evidence ◽  
Pet Ct ◽  
Fdg Pet Ct

In the present review, the authors report the published evidence on the use of functional imaging with FDG-PET/CT in assessing the final response to treatment in Hodgkin lymphoma. Despite a very high overall Negative Predictive Value of post-chemotherapy PET on treatment outcome ranging from 94% to 86%, according to different treatment intensity, the Positive Predicting Value proved much lower (40–25%). In the present review the Authors discuss the role of PET to guide consolidation RT over a RM after different chemotherapy regimens, both in early and in advanced-stage disease. A particular emphasis is dedicated to the peculiar issue of the qualitative versus semi-quantitative methods for End-of Therapy PET scan interpretation. A short hint will be given on the role of FDG-PET to assess the treatment outcome after immune checkpoint inhibitors.

Annual review of research

2003 ◽  
Vol 36 (3) ◽  
pp. 165-189 ◽  
Author(s):  
Richard Johnstone
Keyword(s):  
Information And Communications Technology ◽  
Present Review ◽  
Annual Review ◽  
Communications Technology ◽  
Pedagogical Practice ◽  
Separate Section ◽  
Important Trend ◽  
The Impact

The present review refers to studies published in 2002 in leading research journals. It focuses in particular on learning, teaching and policy in respect of second, modern foreign or additional languages. The comments offered about particular studies are not intended to summarise them (for that, it is best to refer to the actual abstracts which the present journal publishes). What is on offer is a personal selection made because some aspect of a particular article seemed to be of particular interest or to reflect an important trend, and I have attempted to link such elements together to form a narrative. Compared with previous years, two important themes seemed to gather particular momentum in 2002: first, the role of ‘frequency’ in acquisition; and second, the impact of complex and contradictory global factors on everyday pedagogical practice, thinking and attitudes. As in previous years reference is made to the abstracts. Thus, Tarone (2002: 03-158) refers to an article by Tarone published in 2002 and reflected in the 2003 series of this journal as abstract 158. In previous years I have discussed ICT (information and communications technology) in a separate section of its own but this has now been integrated into other sections, reflecting a process of ‘normalisation’.

scholarly journals Critical role of Brg1 member of the SWI/SNF chromatin remodeling complex during neurogenesis and neural crest induction in zebrafish

2006 ◽  
Vol 235 (10) ◽  
pp. 2722-2735 ◽  
Author(s):  
Binnur Eroglu ◽  
Guanghu Wang ◽  
Naxin Tu ◽  
Xutong Sun ◽  
Nahid F. Mivechi
Keyword(s):  
Neural Crest ◽  
Chromatin Remodeling ◽  
Critical Role ◽  
Chromatin Remodeling Complex

scholarly journals The Role of Neural Crest during Cardiac Development in a Mouse Model of DiGeorge Syndrome

2002 ◽  
Vol 251 (1) ◽  
pp. 157-166 ◽  
Author(s):  
Lazaros Kochilas ◽  
Sandra Merscher-Gomez ◽  
Min Min Lu ◽  
Vijaya Potluri ◽  
Jun Liao ◽  
...  
Keyword(s):  
Mouse Model ◽  
Neural Crest ◽  
Digeorge Syndrome ◽  
Cardiac Development

Role of the neural crest in development of the trabeculae and branchial arches in embryonic sea lamprey, Petromyzon marinus (L)

Development ◽  
1988 ◽  
Vol 102 (2) ◽  
pp. 301-310 ◽  
Author(s):  
R.M. Langille ◽  
B.K. Hall
Keyword(s):  
Neural Crest ◽  
Skeletal Development ◽  
Petromyzon Marinus ◽  
Branchial Arches ◽  
Artificial Fertilization ◽  
Vertebrate Skeleton ◽  
The Brain ◽  
Head Skeleton ◽  
Neurula Stage

Lamprey embryos were obtained by artificial fertilization to ascertain the contributions made by the neural crest to the head skeleton. Early-neurula-stage embryos of Petromyzon marinus were subjected to neural crest extirpation along the anterior half from one of seven zones, raised to a larval stage at which control larvae exhibit well-developed skeletons and analysed by light microscopy for any abnormalities to the cranial and visceral skeleton. The removal of premigratory neural crest at the level of the anterior prosencephalon (zone I) and at the level of somites 6 to 8 (zone VII) had no effect on skeletal development. However, the extirpation of neural crest from the intervening regions was positively correlated with deletions/reductions to the trabeculae (basicranial elements) and to the branchial arches (viscerocranial elements). Alterations to the trabeculae (16/27 cases, or 59%) occurred only after extirpation of zones II-V (corresponding to the posterior prosencephalon to midrhombencephalon) while alterations to the branchial arches (21/28 cases, or 75%) occurred only after removal of neural crest from zones III-VI (corresponding to the mesencephalon to the level of the fifth somite). Furthermore, the first three branchial arches were correlated in a majority of cases with neural crest from zone III, the next two arches with zones IV, V and VI and the last two arches with zone VI. Organs that develop within or adjacent to the area of neural crest extirpation such as the brain, notochord and lateral mesodermal derivatives were not affected. Parachordals were never altered by the operations nor were there any discernible changes to developing mucocartilage or to the prechondrogenic otic capsule. The contributions of the neural crest to the petromyzonid head skeleton described herein are compared with the roles of neural crest in the development of cranial and visceral skeletal elements in other vertebrates. The importance of these findings to the current hypothesis of the phylogeny of the vertebrate skeleton and the central role of the neural crest in vertebrate cephalization is discussed.

scholarly journals Role of FGF signalling in neural crest cell migration during early chick embryo development

Zygote ◽  
2018 ◽  
Vol 26 (6) ◽  
pp. 457-464 ◽  
Author(s):  
Xiao-tan Zhang ◽  
Guang Wang ◽  
Yan Li ◽  
Manli Chuai ◽  
Kenneth Ka Ho Lee ◽  
...  
Keyword(s):  
Neural Crest ◽  
Neural Tube ◽  
Neural Crest Cell ◽  
Dominant Negative ◽  
Neural Tubes ◽  
Dorsal Neural Tube ◽  
Neural Crest Cell Migration ◽  
Fgf Signalling ◽  
Crest Cell

SummaryFibroblast growth factor (FGF) signalling acts as one of modulators that control neural crest cell (NCC) migration, but how this is achieved is still unclear. In this study, we investigated the effects of FGF signalling on NCC migration by blocking this process. Constructs that were capable of inducing Sprouty2 (Spry2) or dominant-negative FGFR1 (Dn-FGFR1) expression were transfected into the cells making up the neural tubes. Our results revealed that blocking FGF signalling at stage HH10 (neurulation stage) could enhance NCC migration at both the cranial and trunk levels in the developing embryos. It was established that FGF-mediated NCC migration was not due to altering the expression of N-cadherin in the neural tube. Instead, we determined that cyclin D1 was overexpressed in the cranial and trunk levels when Sprouty2 was upregulated in the dorsal neural tube. These results imply that the cell cycle was a target of FGF signalling through which it regulates NCC migration at the neurulation stage.

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