Hyaluronan as a propellant for epithelial movement: the development of semicircular canals in the inner ear of Xenopus

Development ◽  
1991 ◽  
Vol 112 (2) ◽  
pp. 541-550 ◽  
Author(s):  
C.M. Haddon ◽  
J.H. Lewis
Keyword(s):  
Extracellular Matrix ◽  
Hyaluronic Acid ◽  
Inner Ear ◽  
Semicircular Canal ◽  
Semicircular Canals ◽  
Otic Vesicle ◽  
Membranous Labyrinth ◽  
The Core ◽  
Secondary Palate

The membranous labyrinth of the inner ear, with its three semicircular canals, originates from a simple spheroidal otic vesicle. The process is easily observed in Xenopus. The vesicle develops three dorsal outpocketings; from the two opposite faces of each outpocketing pillars of tissue are protruded into the lumen; and these paired ‘axial protrusions’ eventually meet and fuse, to form a column of tissue spanning the lumen of the outpocketing like the hub of a wheel, with a tube of epithelium forming the semicircular canal around the periphery. Each axial protrusion consists of epithelium encasing a core of largely cell-free extracellular matrix that stains strongly with alcian blue. In sections, at least 60% of the stainable material is removed by treatment with Streptomyces hyaluronidase. When Streptomyces hyaluronidase is microinjected into the core of a protrusion in vivo, the protrusion collapses and the corresponding semicircular canal fails to form. Hyaluronan (hyaluronic acid) in the core of the protrusion therefore seems to be essential in driving the extension of the protrusion. Autoradiography with tritiated glucosamine indicates that the hyaluronan-rich matrix is synthesised by the epithelium covering the tip of the protrusion; the basal lamina here appears to be discontinuous. These findings indicate that the epithelium of the axial protrusion propels itself into the lumen of the otocyst by localised synthesis of hyaluronan. Hyaluronan may be used in a similar way in the development of other organs, such as the heart and the secondary palate.

Nkx5-1 controls semicircular canal formation in the mouse inner ear

Development ◽  
1998 ◽  
Vol 125 (1) ◽  
pp. 33-39 ◽  
Author(s):  
T. Hadrys ◽  
T. Braun ◽  
S. Rinkwitz-Brandt ◽  
H.H. Arnold ◽  
E. Bober
Keyword(s):  
Homologous Recombination ◽  
Inner Ear ◽  
Homeobox Gene ◽  
Semicircular Canals ◽  
Otic Vesicle ◽  
Null Mutation ◽  
Complex Structures ◽  
Vestibular Organ ◽  
Inner Ear Development ◽  
Vestibular Organs

The inner ear develops from the otic vesicle, a one-cell-thick epithelium, which eventually transforms into highly complex structures including the sensory organs for balance (vestibulum) and hearing (cochlea). Several mouse inner ear mutations with hearing and balance defects have been described but for most the underlying genes have not been identified, for example, the genes controlling the development of the vestibular organs. Here, we report the inactivation of the homeobox gene, Nkx5-1, by homologous recombination in mice. This gene is expressed in vestibular structures throughout inner ear development. Mice carrying the Nkx5-1 null mutation exhibit behavioural abnormalities that resemble the typical hyperactivity and circling movements of the shaker/waltzer type mutants. The balance defect correlates with severe malformations of the vestibular organ in Nkx5-1(−/−) mutants, which fail to develop the semicircular canals. Nkx5-1 is the first ear-specific molecule identified to play a crucial role in the formation of the mammalian vestibular system.

Mutations affecting development of the zebrafish inner ear and lateral line

Development ◽  
1996 ◽  
Vol 123 (1) ◽  
pp. 241-254 ◽  
Author(s):  
T.T. Whitfield ◽  
M. Granato ◽  
F.J. van Eeden ◽  
U. Schach ◽  
M. Brand ◽  
...  
Keyword(s):  
Inner Ear ◽  
Lateral Line ◽  
Large Scale ◽  
Sensory System ◽  
Semicircular Canals ◽  
Abnormal Development ◽  
Pigment Cells ◽  
Otic Vesicle ◽  
In The Wild ◽  
Complementation Groups

Mutations giving rise to anatomical defects in the inner ear have been isolated in a large scale screen for mutations causing visible abnormalities in the zebrafish embryo (Haffter, P., Granato, M., Brand, M. et al. (1996) Development 123, 1–36). 58 mutants have been classified as having a primary ear phenotype; these fall into several phenotypic classes, affecting presence or size of the otoliths, size and shape of the otic vesicle and formation of the semicircular canals, and define at least 20 complementation groups. Mutations in seven genes cause loss of one or both otoliths, but do not appear to affect development of other structures within the ear. Mutations in seven genes affect morphology and patterning of the inner ear epithelium, including formation of the semicircular canals and, in some, development of sensory patches (maculae and cristae). Within this class, dog-eared mutants show abnormal development of semicircular canals and lack cristae within the ear, while in van gogh, semicircular canals fail to form altogether, resulting in a tiny otic vesicle containing a single sensory patch. Both these mutants show defects in the expression of homeobox genes within the otic vesicle. In a further class of mutants, ear size is affected while patterning appears to be relatively normal; mutations in three genes cause expansion of the otic vesicle, while in little ears and microtic, the ear is abnormally small, but still contains all five sensory patches, as in the wild type. Many of the ear and otolith mutants show an expected behavioural phenotype: embryos fail to balance correctly, and may swim on their sides, upside down, or in circles. Several mutants with similar balance defects have also been isolated that have no obvious structural ear defect, but that may include mutants with vestibular dysfunction of the inner ear (Granato, M., van Eeden, F. J. M., Schach, U. et al. (1996) Development, 123, 399–413,). Mutations in 19 genes causing primary defects in other structures also show an ear defect. In particular, ear phenotypes are often found in conjunction with defects of neural crest derivatives (pigment cells and/or cartilaginous elements of the jaw). At least one mutant, dog-eared, shows defects in both the ear and another placodally derived sensory system, the lateral line, while hypersensitive mutants have additional trunk lateral line organs.

Computed Tomography and Magnetic Resonance Imaging of the Inner Ear

1988 ◽  
Vol 99 (5) ◽  
pp. 494-504 ◽  
Author(s):  
Robert K. Jackler ◽  
William P. Dillon
Keyword(s):  
Magnetic Resonance Imaging ◽  
Computed Tomography ◽  
Magnetic Resonance ◽  
Inner Ear ◽  
Semicircular Canals ◽  
Resonance Imaging ◽  
High Resolution Computed Tomography ◽  
Membranous Labyrinth ◽  
Prosthetic Devices ◽  
Ear Malformations

The majority of temporal bone radiographic studies are obtained either for middle ear and mastoid disease or in the evaluation of retrocochlear pathology. With recent technologic advances, diagnostic imaging of the inner ear has developed an increasing role in the evaluation and management of diseases that affect the cochlea, semicircular canals, and the vestibular and cochlear aqueducts. High-resolution computed tomography (CT) provides excellent detail of the osseous labyrinth, whereas magnetic resonance imaging (MRI) generates images derived from the membranous labyrinth and its associated neural elements. Optimal techniques for obtaining high quality CT and MRI images of the normal and diseased inner ear are presented. CT has proved useful in the evaluation of inner ear malformations, cochlear otosclerosis, labyrinthine fistulization from cholesteatoma, translabyrinthine fractures, otic capsule osteodystrophies, in the assessment of cochlear patency before cochlear implantation, and in the localization of prosthetic devices such as stapes wires and cochlear implants. While MRI produces discernible images of the soft tissue and fluid components of the inner ear, it has yet to demonstrate any unique advantages in the evaluation of inner ear disease. However, MRI produces excellent and highly useful images of the audiovestibular and facial nerves, cerebellopontine angle, and brain.

scholarly journals Cumulus Cell Expansion, Its Role in Oocyte Biology and Perspectives of Measurement: A Review

2015 ◽  
Vol 45 (4) ◽  
pp. 212-225 ◽  
Author(s):  
J. Nevoral ◽  
M. Orsák ◽  
P. Klein ◽  
J. Petr ◽  
M. Dvořáková ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Hyaluronic Acid ◽  
High Performance ◽  
Uv Light ◽  
Cumulus Cell ◽  
Developmental Competence ◽  
Enzyme Linked Immunosorbent Assay ◽  
Cumulus Expansion

Abstract Cumulus expansion of the cumulus-oocyte complex is necessary for meiotic maturation and acquiring developmental competence. Cumulus expansion is based on extracellular matrix synthesis by cumulus cells. Hyaluronic acid is the most abundant component of this extracellular matrix. Cumulus expansion takes place during meiotic oocyte maturation under in vivo and in vitro conditions. Quantification and measurement of cumulus expansion intensity is one possible method of determining oocyte quality and optimizing conditions for in vitro cultivation. Currently, subjective methods of expanded area and more exact cumulus expansion measurement by hyaluronic acid assessment are available. Among the methods of hyaluronic acid measurement is the use of radioactively labelled synthesis precursors. Alternatively, immunological and analytical methods, including enzyme-linked immunosorbent assay (ELISA), spectrophotometry, and high-performance liquid chromatography (HPLC) in UV light, could be utilized. The high sensitivity of these methods could provide a precise analysis of cumulus expansion without the use of radioisotopes. Therefore, the aim of this review is to summarize and compare available approaches of cumulus expansion measurement, respecting special biological features of expanded cumuli, and to suggest possible solutions for exact cumulus expansion analysis.

scholarly journals The Sound of Silence: Mouse Models for Hearing Loss

2011 ◽  
Vol 2011 ◽  
pp. 1-9 ◽  
Author(s):  
Sumantra Chatterjee ◽  
Thomas Lufkin
Keyword(s):  
Hearing Loss ◽  
Inner Ear ◽  
Hearing Impairment ◽  
Economic Loss ◽  
Signaling Cascades ◽  
Otic Vesicle ◽  
New Genes ◽  
Personal Loss ◽  
The Individual

Sensorineural hearing loss is one of the most common disabilities in humans. It is estimated that about 278 million people worldwide have slight to extreme hearing loss in both ears, which results in an economic loss for the country and personal loss for the individual. It is thus critical to have a deeper understanding of the causes for hearing loss to better manage and treat the affected individuals. The mouse serves as an excellent model to study and recapitulate some of these phenotypes, identify new genes which cause deafness, and to study their roles in vivo and in detail. Mutant mice have been instrumental in elucidating the function and mechanisms of the inner ear. The development and morphogenesis of the inner ear from an ectodermal layer into distinct auditory and vestibular components depends on well-coordinated gene expression and well-orchestrated signaling cascades within the otic vesicle and interactions with surrounding layers of tissues. Any disruption in these pathways can lead to hearing impairment. This review takes a look at some of the genes and their corresponding mice mutants that have shed light on the mechanism governing hearing impairment (HI) in humans.

Volumetric Rendering of Human Inner Ear by MR Imaging

2008 ◽  
Vol 139 (2_suppl) ◽  
pp. P103-P103
Author(s):  
Jen-Fang Yu ◽  
Wei-Chung Chin ◽  
Che-Ming Wu ◽  
Shu-Hang Ng
Keyword(s):  
Mr Imaging ◽  
Inner Ear ◽  
3D Model ◽  
Semicircular Canals ◽  
Vestibular Aqueduct ◽  
3D Geometry ◽  
Large Vestibular Aqueduct Syndrome ◽  
Volumetric Rendering ◽  
Human Inner Ear

Problem To non-invasively measure in-vivo human inner ear by MRI and measure the geometry of vestibule by the reconstructed 3D model of inner ear for further diagnosis of large vestibular aqueduct syndrome (LVAS). Methods 3-T MR scanner, MAGNETOM Trio made by Siemens, was utilized. The TR/TE for MR imaging of 7 patients was 5.65/2.6 ms and the voxel size was 0.5 mm X 0.5 mm X 0.5 mm for single slice of 48 slices. The configuration of semicircular canals, vestibule and cochlea could be detected by threshold. The 3D geometry of inner ear was then computed based on the thickness of slice. Results The surface area and volume of semicircular canals for 7 normal ears were 217.85 square mm and 63.56 cubic mm; of vestibule were 105.88 square mm and 56.36 cubic mm; of cochlea were 171.84 square mm and 81.29 cubic mm respectively. The variation of volumes of vestibule and cochlea could be quantified non-invasively. The correlation between the volume and the level of LVAS will be analyzed once the number of volunteer reaches a statistically significant level. Conclusion The variation for the geometry of vestibule could be measured non-invasively. The grade of LVAS can be assessed by the obtained 3D model of semi-circular canal, vestibule and cochlea. Significance According to the 3D model, the geometry of inner ear can be measured, and the syndrome can be revealed directly to help clinical diagnosis of LVAS more accurately.

How I do it: underwater endoscopic ear surgery for plugging in superior canal dehiscence syndrome

2017 ◽  
Vol 131 (8) ◽  
pp. 745-748 ◽  
Author(s):  
D Yamauchi ◽  
Y Hara ◽  
H Hidaka ◽  
T Kawase ◽  
Y Katori
Keyword(s):  
Inner Ear ◽  
Semicircular Canal ◽  
Saline Water ◽  
Mastoid Cavity ◽  
Endoscopic Ear Surgery ◽  
Ear Surgery ◽  
Membranous Labyrinth ◽  
Endoscopic View ◽  
Superior Canal Dehiscence ◽  
Canal Dehiscence

AbstractBackground:Underwater endoscopic ear surgery does not require suction and so protects the inner ear from unexpected aeration that may damage its function in the treatment of labyrinthine fistula. A method of underwater endoscopic ear surgery is proposed for the treatment of superior canal dehiscence.Methods:Underwater endoscopic ear surgery was performed for plugging of the superior semicircular canal through the transmastoid approach. Saline solution was infused into the mastoid cavity through an Endo-Scrub Lens Cleaning Sheath. The tip of the inserted endoscope was filled completely with saline water.Results:Using this underwater endoscopic view, the canal was clearly dissected to expose the semicircular canal membranous labyrinth and dehiscence area. No particular complication occurred during the surgical procedure.Conclusion:The underwater endoscopic ear surgery technique for plugging in superior canal dehiscence secures an excellent visual field and protects the inner ear from unexpected aeration.

scholarly journals A Third Labyrinthine Window: An Overview of Perilymph and Labyrinthine Fistulae and Superior Semicircular Canal Dehiscence

2012 ◽  
Vol 4 (2) ◽  
pp. 100-105 ◽  
Keyword(s):  
Inner Ear ◽  
Semicircular Canal ◽  
Membranous Labyrinth ◽  
Superior Semicircular Canal Dehiscence ◽  
Bony Labyrinth ◽  
Superior Semicircular Canal ◽  
Inner Ear Fluids ◽  
Canal Dehiscence

ABSTRACT The membranous labyrinth is contained within the bony labyrinth and surrounded by perilymph. The only two ‘potentially yielding’ parts of the otherwise solid bony labyrinth are the oval and round windows, which by their relative movements, pressure differentials and resilience are responsible for all the functions attributed to the inner ear. In pathologies, such as trauma, infection or occasionally congenital dehiscence, there may develop a ‘third window’ that may serve as an abnormal communication for the inner ear fluids and manifest with audiovestibular symptoms. Three such distinct entities have been identified, namely ‘superior semicircular canal dehiscence syndrome, perilymphatic fistulae and labyrinthine fistulae’. This overview intends to discuss these above-mentioned entities, as regards their characteristic presentations and principles of management. How to cite this article Hathiram BT, Khattar VS. A Third Labyrinthine Window: An Overview of Perilymph and Labyrinthine Fistulae and Superior Semicircular Canal Dehiscence. Otorhinolaryngol Clin Int J 2012;4(2):100-105.

scholarly journals Hyaluronic acid-functionalized gelatin hydrogels reveal extracellular matrix signals temper the efficacy of erlotinib against patient-derived glioblastoma specimens

2019 ◽  
Author(s):  
Sara Pedron ◽  
Gabrielle L. Wolter ◽  
Jee-Wei E. Chen ◽  
Sarah E. Laken ◽  
Jann N. Sarkaria ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Hyaluronic Acid ◽  
Tumor Microenvironment ◽  
Kinase Inhibitor ◽  
Egfr Mutations ◽  
Primary Glioblastoma ◽  
Stat3 Phosphorylation

AbstractTherapeutic options to treat primary glioblastoma (GBM) tumors are scarce. GBM tumors with epidermal growth factor receptor (EGFR) mutations, in particular a constitutively active EGFRvIII mutant, have extremely poor clinical outcomes. GBM tumors with concurrent EGFR amplification and active phosphatase and tensin homolog (PTEN) are sensitive to the tyrosine kinase inhibitor erlotinib, but the effect is not durable. A persistent challenge to improved treatment is the poorly understood role of cellular, metabolic, and biophysical signals from the GBM tumor microenvironment on therapeutic efficacy and acquired resistance. The intractable nature of studying GBM cell in vivo motivates tissue engineering approaches to replicate aspects of the complex GBM tumor microenvironment. Here, we profile the effect of erlotinib on two patient-derived GBM specimens: EGFR+ GBM12 and EGFRvIII GBM6. We use a three-dimensional gelatin hydrogel to present brain-mimetic hyaluronic acid (HA) and evaluate the coordinated influence of extracellular matrix signals and EGFR mutation status on GBM cell migration, survival and proliferation, as well as signaling pathway activation in response to cyclic erlotinib exposure. Comparable to results observed in vivo for xenograft tumors, erlotinib exposure is not cytotoxic for GBM6 EGFRvIII specimens. We also identify a role of extracellular HA (via CD44) in altering the effect of erlotinib in GBM EGFR+ cells by modifying STAT3 phosphorylation status. Taken together, we report an in vitro tissue engineered platform to monitor signaling associated with poor response to targeted inhibitors in GBM.

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