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Jose Francisco Rodríguez-vázquez - One of the best experts on this subject based on the ideXlab platform.
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Prestyloid compartment of the paraPharyngeal space: a histological study using late-stage human fetuses
Surgical and Radiologic Anatomy, 2012Co-Authors: Yukio Katori, Jose Francisco Rodríguez-vázquez, Hiroshi Abe, Tatsuaki Kawase, Kwang Ho Cho, Gen Murakami, Shinichi AbeAbstract:Purpose Although the prestyloid space is well known, its definition still remains unclear. Methods Using semiserial sagittal sections of 15 late-stage human fetal heads, we studied details of the topographical anatomy. Results A definite posterior marginal fascia of the space was seen along the anterior aspect of the stylopharyngeus and styloglossus muscles. Inferiorly, the prestyloid space faced the bucallis and medial pterygoid muscles and the submandibular gland. The external carotid artery ran along the posterolateral side of the space. The tensor veli palatini fascia did not contribute to the posterior marginal fascia. A major supplying artery of the space was the ascending palatine artery. Conclusions The prestyloid compartment of the paraPharyngeal space (hereafter, the prestyloid space) seems to correspond to a border between the first and Second Pharyngeal Arch derivatives. This concept may provide a better understanding of prestyloid space.
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Fetal development and variations in the cartilages surrounding the human external acoustic meatus.
Annals of anatomy = Anatomischer Anzeiger : official organ of the Anatomische Gesellschaft, 2012Co-Authors: Yasutoyo Ikari, Yukio Katori, Aiji Ohtsuka, Jose Francisco Rodríguez-vázquez, Hiroshi Abe, Tetsuaki Kawase, Murakami, Shinichi AbeAbstract:Summary In contrast to the osseus part that develops from the tympanic ring of the squamous part of the temporal bone after birth, there is little information on fetal development of the cartilages surrounding the human external acoustic meatus. Using routine histology and immunohistochemistry, we examine sections of 22 fetuses (CRL 100–270 mm) to study the development of these cartilages. Early external ear cartilages are composed of three groups: (1) a ring-like cartilage at the putative tragus on the anterior side of the meatus, (2) two or three bar-like cartilages along the inferior wall of the meatus, and (3) a plate-like cartilage in a skin fold for the putative helix on the posterior side. In contrast to the first and Second Pharyngeal Arch cartilages, all the external ear cartilages express glial fibrillary acidic protein. Notably, the bar-like cartilages along the meatus are connected with a fascia-like structure to the Second Pharyngeal Arch cartilage. Later, with considerable individual variation, new cartilage bars extend from the inferior cartilages to the superior side of the meatus. Thus, via an intermediate stage showing a chain of triangular elastic cartilages, a chain of bar-like cartilages on the inferior side appears to change into a complex of H-shaped cartilages. Numerous ceruminous glands are seen in the thick subcutaneous tissue overlying the cartilaginous part of the meatus. However, they do not insert into the cartilage. The external ear cartilages develop much earlier than, and independently of, the osseus part.
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Development of the Stapedius Muscle and Unilateral Agenesia of the Tendon of the Stapedius Muscle in a Human Fetus
Anatomical record (Hoboken N.J. : 2007), 2009Co-Authors: Jose Francisco Rodríguez-vázquez, J.r. Mérida-velasco, Samuel Verdugo-lópezAbstract:The objective was to analyze the development of the stapedius muscle to understand an isolated unilateral absence of the tendon of the stapedius muscle in a human fetus. The study was made on 50 human embryos and fetuses aged 38 days to 17 weeks post-conception. The stapedius muscle was formed by two anlagen, one for the tendon, which derives from the internal segment of the interhyale and another for the belly, located in the Second Pharyngeal Arch, medially to the facial nerve and near the interhyale. In the interhyale, two segments were observed forming an angle and delimited by the attachment of the belly of the stapedius muscle. The internal segment will form the tendon. The lateral segment of the interhyale was attached to the cranial end of the Reichert's cartilage (laterohyale), and normally it disappears at the beginning of the fetal period. The right unilateral agenesia of the tendon of the stapedius muscle, observed for the first time in a human fetus of 14 weeks post-conception development (PCd), was brought about by the lack of formation or the regression of the internal segment of the interhyale. It presented a belly of the stapedius muscle with an anomalous arrangement, and with a pseudo tendon originated by the persistence of the external segment of the interhyale.
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Development of the stapedius muscle and pyramidal eminence in humans.
Journal of anatomy, 2009Co-Authors: Jose Francisco Rodríguez-vázquezAbstract:The aim of the study was to systematize the key developmental phases of the stapedius muscle and the pyramidal eminence to clarify their formation, as well as to understand the variations and anomalies that can affect these structures. Sixty human embryos and fetuses between 38 days and 17 weeks of development were studied. The stapedius muscle is formed by two anlagen, one for the tendon, which derives from the internal segment of the interhyale, and another for the belly, located in the Second Pharyngeal Arch medial to the facial nerve and near the interhyale but forming a completely independent anlage. In the interhyale, two segments were differentiated, these forming an angle; at the vertex, the belly of the stapedius muscle is attached. The internal segment is located from the attachment of the belly of the stapedius muscle to the anlage of the stapes, forming the anlage of the tendon of the stapedius muscle. The external segment completely disappears at the beginning of the fetal period. The pyramidal eminence is formed by an anlage independent of Reichert’s cartilage, from the mesenchymal tissue of the tympanic cavity, which condenses around the belly of the stapedius muscle from 12 weeks of post-conception development. The length of the tendon of the stapedius muscle in adults varies, depending on the attachment site of the belly of the stapedius muscle in the interhyale, which would determine the length of the internal segment (anlage of the tendon) and consequently the tendon length. This variation depends on the greater or lesser persistence of the angulation observed during development, between the tendon and the belly of the stapedius muscle.
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Morphogenesis of the Second Pharyngeal Arch cartilage (Reichert's cartilage) in human embryos
Journal of anatomy, 2006Co-Authors: Jose Francisco Rodríguez-vázquez, J.r. Mérida-velasco, Samuel Verdugo-lópez, Indalecio Sánchez-montesinosAbstract:This study was performed on 50 human embryos and fetuses between 7 and 17 weeks of development. Reichert's cartilage is formed in the Second Pharyngeal Arch in two segments. The longer cranial or styloid segment is continuous with the otic capsule; its inferior end is angulated and is situated very close to the oropharynx. The smaller caudal segment is in contact with the body and greater horn of the hyoid cartilaginous structure. No cartilage forms between these segments. The persistent angulation of the inferior end of the cranial or styloid segment of Reichert's cartilage and its important neurovascular relationships may help explain the symptomatology of Eagle's syndrome.
J.r. Mérida-velasco - One of the best experts on this subject based on the ideXlab platform.
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J. Anat. (2006) 208, pp179–189 Morphogenesis of the Second Pharyngeal Arch cartilage Blackwell Publishing Ltd
2013Co-Authors: J.r. Mérida-velascoAbstract:This study was performed on 50 human embryos and fetuses between 7 and 17 weeks of development. Reichert’s cartilage is formed in the Second Pharyngeal Arch in two segments. The longer cranial or styloid segment is continuous with the otic capsule; its inferior end is angulated and is situated very close to the oropharynx. The smaller caudal segment is in contact with the body and greater horn of the hyoid cartilaginous structure. No cartilage forms between these segments. The persistent angulation of the inferior end of the cranial or styloid segment of Reichert’s cartilage and its important neurovascular relationships may help explain the symptomatology of Eagle’s syndrome. Key words Eagle’s syndrome; human embryology; Pharyngeal Arches; Reichert’s cartilage
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Development of the Stapedius Muscle and Unilateral Agenesia of the Tendon of the Stapedius Muscle in a Human Fetus
Anatomical record (Hoboken N.J. : 2007), 2009Co-Authors: Jose Francisco Rodríguez-vázquez, J.r. Mérida-velasco, Samuel Verdugo-lópezAbstract:The objective was to analyze the development of the stapedius muscle to understand an isolated unilateral absence of the tendon of the stapedius muscle in a human fetus. The study was made on 50 human embryos and fetuses aged 38 days to 17 weeks post-conception. The stapedius muscle was formed by two anlagen, one for the tendon, which derives from the internal segment of the interhyale and another for the belly, located in the Second Pharyngeal Arch, medially to the facial nerve and near the interhyale. In the interhyale, two segments were observed forming an angle and delimited by the attachment of the belly of the stapedius muscle. The internal segment will form the tendon. The lateral segment of the interhyale was attached to the cranial end of the Reichert's cartilage (laterohyale), and normally it disappears at the beginning of the fetal period. The right unilateral agenesia of the tendon of the stapedius muscle, observed for the first time in a human fetus of 14 weeks post-conception development (PCd), was brought about by the lack of formation or the regression of the internal segment of the interhyale. It presented a belly of the stapedius muscle with an anomalous arrangement, and with a pseudo tendon originated by the persistence of the external segment of the interhyale.
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Morphogenesis of the Second Pharyngeal Arch cartilage (Reichert's cartilage) in human embryos
Journal of anatomy, 2006Co-Authors: Jose Francisco Rodríguez-vázquez, J.r. Mérida-velasco, Samuel Verdugo-lópez, Indalecio Sánchez-montesinosAbstract:This study was performed on 50 human embryos and fetuses between 7 and 17 weeks of development. Reichert's cartilage is formed in the Second Pharyngeal Arch in two segments. The longer cranial or styloid segment is continuous with the otic capsule; its inferior end is angulated and is situated very close to the oropharynx. The smaller caudal segment is in contact with the body and greater horn of the hyoid cartilaginous structure. No cartilage forms between these segments. The persistent angulation of the inferior end of the cranial or styloid segment of Reichert's cartilage and its important neurovascular relationships may help explain the symptomatology of Eagle's syndrome.
Samuel Verdugo-lópez - One of the best experts on this subject based on the ideXlab platform.
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Development of the Stapedius Muscle and Unilateral Agenesia of the Tendon of the Stapedius Muscle in a Human Fetus
Anatomical record (Hoboken N.J. : 2007), 2009Co-Authors: Jose Francisco Rodríguez-vázquez, J.r. Mérida-velasco, Samuel Verdugo-lópezAbstract:The objective was to analyze the development of the stapedius muscle to understand an isolated unilateral absence of the tendon of the stapedius muscle in a human fetus. The study was made on 50 human embryos and fetuses aged 38 days to 17 weeks post-conception. The stapedius muscle was formed by two anlagen, one for the tendon, which derives from the internal segment of the interhyale and another for the belly, located in the Second Pharyngeal Arch, medially to the facial nerve and near the interhyale. In the interhyale, two segments were observed forming an angle and delimited by the attachment of the belly of the stapedius muscle. The internal segment will form the tendon. The lateral segment of the interhyale was attached to the cranial end of the Reichert's cartilage (laterohyale), and normally it disappears at the beginning of the fetal period. The right unilateral agenesia of the tendon of the stapedius muscle, observed for the first time in a human fetus of 14 weeks post-conception development (PCd), was brought about by the lack of formation or the regression of the internal segment of the interhyale. It presented a belly of the stapedius muscle with an anomalous arrangement, and with a pseudo tendon originated by the persistence of the external segment of the interhyale.
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Morphogenesis of the Second Pharyngeal Arch cartilage (Reichert's cartilage) in human embryos
Journal of anatomy, 2006Co-Authors: Jose Francisco Rodríguez-vázquez, J.r. Mérida-velasco, Samuel Verdugo-lópez, Indalecio Sánchez-montesinosAbstract:This study was performed on 50 human embryos and fetuses between 7 and 17 weeks of development. Reichert's cartilage is formed in the Second Pharyngeal Arch in two segments. The longer cranial or styloid segment is continuous with the otic capsule; its inferior end is angulated and is situated very close to the oropharynx. The smaller caudal segment is in contact with the body and greater horn of the hyoid cartilaginous structure. No cartilage forms between these segments. The persistent angulation of the inferior end of the cranial or styloid segment of Reichert's cartilage and its important neurovascular relationships may help explain the symptomatology of Eagle's syndrome.
Edmund J. Stellwag - One of the best experts on this subject based on the ideXlab platform.
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Role of Hox PG2 genes in Nile tilapia Pharyngeal Arch specification: implications for gnathostome Pharyngeal Arch evolution.
Evolution & development, 2010Co-Authors: Pierre Le Pabic, Jean-luc Scemama, Edmund J. StellwagAbstract:SUMMARY Phylogenetic reconstructions suggest that the ancestral osteichthyan Hox paralog group 2 gene complement was composed of two genes, Hoxa2 and b2, both of which have been retained in tetrapods, but only one of which functions as a selector gene of Second Pharyngeal Arch identity (PA2). Genome duplication at the inception of the teleosts likely generated four Hox PG2 genes, only two of which, hoxa2b and b2a, have been preserved in zebrafish, where they serve as functionally redundant PA2 selector genes. Evidence from our laboratory has shown that other telelosts, specifically striped bass and Nile tilapia, harbor three transcribed Hox PG2 genes, hoxa2a, a2b, and b2a, with unspecified function(s). We have focused on characterizing the function of the three Nile tilapia Hox PG2 genes as a model to examine the effects of postgenome duplication gene loss on the evolution of developmental gene function. We studied Hox PG2 gene function in tilapia by examining the effects of independent morpholino oligonucleotide (MO)-induced knockdowns on Pharyngeal Arch morphology and Hox gene expression patterns. Morphological defects resulting from independent MO-induced knockdowns of tilapia hoxa2a, a2b, and b2a included the expected PA2 to PA1 homeotic transformations previously observed in tetrapods and zebrafish, as well as concordant and unexpected morphological changes in posterior Arch-derived cartilages. Of particular interest, was the observation of a MO-induced supernumerary Arch between PA6 and PA7, which occurred concomitantly with other MO-induced Pharyngeal Arch defects. Beyond these previously unreported morphant-induced transformations, a comparison of Hox PG2 gene expression patterns in tilapia Hox PG2 morphants were indicative of Arch-specific auto- and cross-regulatory activities as well as a Hox paralog group 2 interdependent regulatory network for control of Pharyngeal Arch specification.
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Comparative analysis of Hox paralog group 2 gene expression during Nile tilapia (Oreochromis niloticus) embryonic development
Development Genes and Evolution, 2007Co-Authors: Pierre Le Pabic, Edmund J. Stellwag, Shelby N. Brothers, Jean-luc ScemamaAbstract:The hindbrain and Pharyngeal Arch-derived structures of vertebrates are determined, at least in part, by Hox paralog group 2 genes. In sarcopterygians, the Hoxa2 gene alone appears to specify structures derived from the Second Pharyngeal Arch (PA2), while in zebrafish ( Danio rerio ), either of the two Hox PG2 genes, hoxa2b or hoxb2a , can specify PA2-derived structures. We previously reported three Hox PG2 genes in striped bass ( Morone saxatilis ), including hoxa2a , hoxa2b , and hoxb2a and observed that only HoxA cluster genes are expressed in PA2, indicative that they function alone or together to specify PA2. In this paper, we present the cloning and expression analysis of Nile tilapia ( Oreochromis niloticus ) Hox PG2 genes and show that all three genes are expressed in the hindbrain and in PA2. The expression of hoxb2a in PA2 was unexpected given the close phylogenetic relationship of Nile tilapia and striped bass, both of which are members of the order Perciformes. A reanalysis of striped bass hoxb2a expression demonstrated that it is expressed in PA2 with nearly the same temporal and spatial expression pattern as its Nile tilapia ortholog. Further, we determined that Nile tilapia and striped bass hoxa2a orthologs are expressed in PA2 well beyond the onset of chondrogenesis whereas neither hoxa2b nor hoxb2a expression persist until this stage, which, according to previous hypotheses, suggests that hoxa2a orthologs in these two species function alone as selector genes of PA2 identity.
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Differential expression of hoxa2a and hoxa2b genes during striped bass embryonic development.
Gene expression patterns : GEP, 2006Co-Authors: Jean-luc Scemama, Jamie Vernon, Edmund J. StellwagAbstract:Abstract Here, we report the cloning and expression analysis of two previously uncharacterized paralogs group 2 Hox genes, striped bass hoxa2a and hoxa2b , and the developmental regulatory gene egr2 . We demonstrate that both Hox genes are expressed in the rhombomeres of the developing hindbrain and the Pharyngeal Arches albeit with different spatio-temporal distributions relative to one another. While both hoxa2a and hoxa2b share the r1/r2 anterior boundary of expression characteristic of the hoxa2 paralog genes of other species, hoxa2a gene expression extends throughout the hindbrain, whereas hoxa2b gene expression is restricted to the r2–r5 region. Egr2 , which is used in this study as an early developmental marker of rhombomeres 3 and 5, is expressed in two distinct bands with a location and spacing typical for these two rhombomeres in other species. Within the Pharyngeal Arches, hoxa2a is expressed at higher levels in the Second Pharyngeal Arch, while hoxa2b is more strongly expressed in the posterior Arches. Further, hoxa2b expression within the Arches becomes undetectable at 60 hpf, while hoxa2a expression is maintained at least up until the beginning of chondrogenesis. Comparison of the striped bass HoxA cluster paralog group 2 (PG2) genes to their orthologs and trans-orthologs shows that the striped bass hoxa2a gene expression pattern is similar to the overall expression pattern described for the hoxa2 genes in the lobe-finned fish lineage and for the hoxa2b gene from zebrafish. It is notable that the Pharyngeal Arch expression pattern of the striped bass hoxa2a gene is more divergent from its sister paralog, hoxa2b , than from the zebrafish hoxa2b gene. Overall, our results suggest that differences in the Hox PG2 gene complement of striped bass and zebrafish affects both their rhombomeric and Pharyngeal Arch expression patterns and may account for the similarities in Pharyngeal Arch expression between striped bass hoxa2a and zebrafish hoxa2b .
Pierre Le Pabic - One of the best experts on this subject based on the ideXlab platform.
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Role of Hox PG2 genes in Nile tilapia Pharyngeal Arch specification: implications for gnathostome Pharyngeal Arch evolution.
Evolution & development, 2010Co-Authors: Pierre Le Pabic, Jean-luc Scemama, Edmund J. StellwagAbstract:SUMMARY Phylogenetic reconstructions suggest that the ancestral osteichthyan Hox paralog group 2 gene complement was composed of two genes, Hoxa2 and b2, both of which have been retained in tetrapods, but only one of which functions as a selector gene of Second Pharyngeal Arch identity (PA2). Genome duplication at the inception of the teleosts likely generated four Hox PG2 genes, only two of which, hoxa2b and b2a, have been preserved in zebrafish, where they serve as functionally redundant PA2 selector genes. Evidence from our laboratory has shown that other telelosts, specifically striped bass and Nile tilapia, harbor three transcribed Hox PG2 genes, hoxa2a, a2b, and b2a, with unspecified function(s). We have focused on characterizing the function of the three Nile tilapia Hox PG2 genes as a model to examine the effects of postgenome duplication gene loss on the evolution of developmental gene function. We studied Hox PG2 gene function in tilapia by examining the effects of independent morpholino oligonucleotide (MO)-induced knockdowns on Pharyngeal Arch morphology and Hox gene expression patterns. Morphological defects resulting from independent MO-induced knockdowns of tilapia hoxa2a, a2b, and b2a included the expected PA2 to PA1 homeotic transformations previously observed in tetrapods and zebrafish, as well as concordant and unexpected morphological changes in posterior Arch-derived cartilages. Of particular interest, was the observation of a MO-induced supernumerary Arch between PA6 and PA7, which occurred concomitantly with other MO-induced Pharyngeal Arch defects. Beyond these previously unreported morphant-induced transformations, a comparison of Hox PG2 gene expression patterns in tilapia Hox PG2 morphants were indicative of Arch-specific auto- and cross-regulatory activities as well as a Hox paralog group 2 interdependent regulatory network for control of Pharyngeal Arch specification.
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Comparative analysis of Hox paralog group 2 gene expression during Nile tilapia (Oreochromis niloticus) embryonic development
Development Genes and Evolution, 2007Co-Authors: Pierre Le Pabic, Edmund J. Stellwag, Shelby N. Brothers, Jean-luc ScemamaAbstract:The hindbrain and Pharyngeal Arch-derived structures of vertebrates are determined, at least in part, by Hox paralog group 2 genes. In sarcopterygians, the Hoxa2 gene alone appears to specify structures derived from the Second Pharyngeal Arch (PA2), while in zebrafish ( Danio rerio ), either of the two Hox PG2 genes, hoxa2b or hoxb2a , can specify PA2-derived structures. We previously reported three Hox PG2 genes in striped bass ( Morone saxatilis ), including hoxa2a , hoxa2b , and hoxb2a and observed that only HoxA cluster genes are expressed in PA2, indicative that they function alone or together to specify PA2. In this paper, we present the cloning and expression analysis of Nile tilapia ( Oreochromis niloticus ) Hox PG2 genes and show that all three genes are expressed in the hindbrain and in PA2. The expression of hoxb2a in PA2 was unexpected given the close phylogenetic relationship of Nile tilapia and striped bass, both of which are members of the order Perciformes. A reanalysis of striped bass hoxb2a expression demonstrated that it is expressed in PA2 with nearly the same temporal and spatial expression pattern as its Nile tilapia ortholog. Further, we determined that Nile tilapia and striped bass hoxa2a orthologs are expressed in PA2 well beyond the onset of chondrogenesis whereas neither hoxa2b nor hoxb2a expression persist until this stage, which, according to previous hypotheses, suggests that hoxa2a orthologs in these two species function alone as selector genes of PA2 identity.