scholarly journals Malformations of the sacculus and the semicircular canals in spider morph pythons

2022 ◽  
Author(s):  
Matthias J. Starck ◽  
Fabian Schrenk ◽  
Schröder Sofia ◽  
Michael Pees
Keyword(s):  
Inner Ear ◽  
Skin Color ◽  
Semicircular Canals ◽  
Color Pattern ◽  
Wild Type ◽  
Python Regius ◽  
Color Design ◽  
Reconstruction Software ◽  
Semicircular Ducts ◽  
Anatomical Evidence

Spider morph ball pythons are a frequently bred design morph with striking alterations of the skin color pattern. We created high resolution µCT-image series through the otical region of the skulls, used 3D-reconstruction software for rendering anatomical models, and compare the anatomy of the semicircular ducts, sacculus and ampullae of wildtype Python regius (ball python) with spider morph snakes. All spider morph snakes showed the wobble condition. We describe the inner ear structures in wild-type and spider-morph snakes and report a deviant morphology of semicircular canals, ampullae and sacculus in spider morph snakes. We also report about associated differences in the desmal skull bones of spider morph snakes. The spider morph snakes were characterized by wider semicircular canals, anatomically poorly defined ampulla, a deformed crus communis and a small sacculus, with a highly deviant x-ray morphology as compared to wildtype individuals. We observed considerable intra- and interindividual variability of these features. This deviant morphology of spider morph snakes can easily be associated with an impairment of sense of equilibrium and the observed neurological wobble condition. Limitations in sample size prevent statistical analyses, but the anatomical evidence is strong enough to support an association between the wobble condition in design bread spider morph snakes and a malformation of the inner ear structures. A link between artificially selected alterations in pattern and specific color design with neural-crest associated developmental malformations of the statoacoustic organ as known from other vertebrates is discussed.

scholarly journals In situ differentiation of iridophore crystallotypes underlies zebrafish stripe patterning

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Dvir Gur ◽  
Emily J. Bain ◽  
Kory R. Johnson ◽  
Andy J. Aman ◽  
H. Amalia Pasoili ◽  
...  
Keyword(s):  
Skin Color ◽  
Cell Types ◽  
Color Pattern ◽  
Single Type ◽  
Sequencing Analysis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cryogenic Scanning Electron Microscopy ◽  
Different Cell Types

AbstractSkin color patterns are ubiquitous in nature, impact social behavior, predator avoidance, and protection from ultraviolet irradiation. A leading model system for vertebrate skin patterning is the zebrafish; its alternating blue stripes and yellow interstripes depend on light-reflecting cells called iridophores. It was suggested that the zebrafish’s color pattern arises from a single type of iridophore migrating differentially to stripes and interstripes. However, here we find that iridophores do not migrate between stripes and interstripes but instead differentiate and proliferate in-place, based on their micro-environment. RNA-sequencing analysis further reveals that stripe and interstripe iridophores have different transcriptomic states, while cryogenic-scanning-electron-microscopy and micro-X-ray diffraction identify different crystal-arrays architectures, indicating that stripe and interstripe iridophores are different cell types. Based on these results, we present an alternative model of skin patterning in zebrafish in which distinct iridophore crystallotypes containing specialized, physiologically responsive, organelles arise in stripe and interstripe by in-situ differentiation.

scholarly journals Gene therapy via canalostomy approach preserves auditory and vestibular functions in a mouse model of Jervell and Lange-Nielsen syndrome type 2

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Xuewen Wu ◽  
Li Zhang ◽  
Yihui Li ◽  
Wenjuan Zhang ◽  
Jianjun Wang ◽  
...  
Keyword(s):  
Gene Therapy ◽  
Mouse Model ◽  
Inner Ear ◽  
Viral Vectors ◽  
Survival Rates ◽  
Semicircular Canals ◽  
Dependent Manner ◽  
Syndrome Type ◽  
Dose Dependent

AbstractMutations in voltage-gated potassium channel KCNE1 cause Jervell and Lange-Nielsen syndrome type 2 (JLNS2), resulting in congenital deafness and vestibular dysfunction. We conducted gene therapy by injecting viral vectors using the canalostomy approach in Kcne1−/− mice to treat both the hearing and vestibular symptoms. Results showed early treatment prevented collapse of the Reissner’s membrane and vestibular wall, retained the normal size of the semicircular canals, and prevented the degeneration of inner ear cells. In a dose-dependent manner, the treatment preserved auditory (16 out of 20 mice) and vestibular (20/20) functions in mice treated with the high-dosage for at least five months. In the low-dosage group, a subgroup of mice (13/20) showed improvements only in the vestibular functions. Results supported that highly efficient transduction is one of the key factors for achieving the efficacy and maintaining the long-term therapeutic effect. Secondary outcomes of treatment included improved birth and litter survival rates. Our results demonstrated that gene therapy via the canalostomy approach, which has been considered to be one of the more feasible delivery methods for human inner ear gene therapy, preserved auditory and vestibular functions in a dose-dependent manner in a mouse model of JLNS2.

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.

Response of clupeid fish to ultrasound: a review

2004 ◽  
Vol 61 (7) ◽  
pp. 1057-1061 ◽  
Author(s):  
Arthur N. Popper ◽  
Dennis T.T. Plachta ◽  
David A. Mann ◽  
Dennis Higgs
Keyword(s):  
Inner Ear ◽  
Sensory Epithelium ◽  
Sound Level ◽  
Behavioural Response ◽  
American Shad ◽  
Low Intensity ◽  
Blueback Herring ◽  
Sound Levels ◽  
Directional Movement ◽  
Anatomical Evidence

Abstract A number of species of clupeid fish, including blueback herring, American shad, and gulf menhaden, can detect and respond to ultrasonic sounds up to at least 180 kHz, whereas other clupeids, including bay anchovies and Spanish sardines, do not appear to detect sounds above about 4 kHz. Although the location for ultrasound detection has not been proven conclusively, there is a growing body of physiological, developmental, and anatomical evidence suggesting that one end organ of the inner ear, the utricle, is likely to be the detector. The utricle is a region of the inner ear that is very similar in all vertebrates studied to date, except for clupeid fish, where it is highly specialized. Behavioural studies of the responses of American shad to ultrasound demonstrate that they show a graded series of responses depending on the sound level and, to a lesser degree, on the frequency of the stimulus. Low-intensity stimuli elicit a non-directional movement of the fish, whereas somewhat higher sound levels elicit a directional movement away from the sound source. Still higher level sounds produce a “wild” chaotic movement of the fish. These responses do not occur until shad have developed the adult utricle that has a three-part sensory epithelium. We speculate that the response of the American shad (and, presumably, other clupeids that can detect ultrasound) to ultrasound evolved to help these species detect and avoid a major predator – echolocating cetaceans. As dolphins echolocate, the fish are able to hear the sound at over 100 m. If the dolphins detect the fish and come closer, the nature of the behavioural response of the fish changes in order to exploit different avoidance strategies and lower the chance of being eaten by the predators.

The Semicircular Canals of the Inner Ear and the Pneumatization of the Temporal Bone

1986 ◽  
Vol 27 (3) ◽  
pp. 325-329
Author(s):  
C. Muren ◽  
H. Wilbrand
Keyword(s):  
Inner Ear ◽  
Temporal Bone ◽  
Semicircular Canals ◽  
Petrous Bone ◽  
General Outline ◽  
Size And Shape ◽  
Wide Range

In an investigation of 94 plastic casts of temporal bone specimens a wide range of variations both in the general outline of the pyramid and in the anatomy of its specific structures was found. Attempts were made to estimate the transverse and vertical dimensions of the petrous bone. Both the mastoid and the perilabyrinthine pneumatization correlated to the dimensions of some structures, but not to the size and shape of the semicircular canals. References

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 A decade of magnetic vestibular stimulation: from serendipity to physics to the clinic

2019 ◽  
Vol 121 (6) ◽  
pp. 2013-2019 ◽  
Author(s):  
Bryan K. Ward ◽  
Dale C. Roberts ◽  
Jorge Otero-Millan ◽  
David S. Zee
Keyword(s):  
Magnetic Fields ◽  
Inner Ear ◽  
Lorentz Force ◽  
Semicircular Canals ◽  
High Strength ◽  
Ionic Currents ◽  
Vestibular Stimulation ◽  
Static Magnetic Fields ◽  
Magnetic Resonance Imaging Mri ◽  
Vestibular Asymmetry

For many years, people working near strong static magnetic fields of magnetic resonance imaging (MRI) machines have reported dizziness and sensations of vertigo. The discovery a decade ago that a sustained nystagmus can be observed in all humans with an intact labyrinth inside MRI machines led to a possible mechanism: a Lorentz force occurring in the labyrinth from the interactions of normal inner ear ionic currents and the strong static magnetic fields of the MRI machine. Inside an MRI, the Lorentz force acts to induce a constant deflection of the semicircular canal cupula of the superior and lateral semicircular canals. This inner ear stimulation creates a sensation of rotation, and a constant horizontal/torsional nystagmus that can only be observed when visual fixation is removed. Over time, the brain adapts to both the perception of rotation and the nystagmus, with the perception usually diminishing over a few minutes, and the nystagmus persisting at a reduced level for hours. This observation has led to discoveries about how the central vestibular mechanisms adapt to a constant vestibular asymmetry and is a useful model of set-point adaptation or how homeostasis is maintained in response to changes in the internal milieu or the external environment. We review what is known about the effects of stimulation of the vestibular system with high-strength magnetic fields and how the understanding of the mechanism has been refined since it was first proposed. We suggest future ways that magnetic vestibular stimulation might be used to understand vestibular disease and how it might be treated.

scholarly journals Gata2 is required for the development of inner ear semicircular ducts and the surrounding perilymphatic space

2010 ◽  
Vol 239 (9) ◽  
pp. 2452-2469 ◽  
Author(s):  
Maarja Haugas ◽  
Kersti Lilleväli ◽  
Janne Hakanen ◽  
Marjo Salminen
Keyword(s):  
Inner Ear ◽  
Semicircular Ducts ◽  
Perilymphatic Space

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.

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