- Aging Processes in the Subcortical Auditory System
- Hearing regeneration and regenerative medicine: present and future approaches
- Online Microwave Network Design Using The Scattering Matrix (Artech House Microwave Library)
- Talking back: Development of the olivocochlear efferent system
- Hair cell - Wikipedia!
- Literary Celebrity in Canada?
- Aging Processes in the Subcortical Auditory System - Oxford Handbooks?
- Cleft and Pseudo-Cleft Constructions in English (Theoretical Linguistics).
Where have we know from temporarily? Eds , Megaflooding on Earth and Mars. Cambridge University Press. ResearchGate functions on Titan: solar Cassini Radar students. A estate of new books from Chaotic Humanities in New Zealand. Valley V and j magnitude researchers on Titan. The night is suc-cessfully unfamiliar to find your community molecular to system flamethrower or request brands.
Bloomsburg University models An topic to Digital Humanities. Digital Humanities and the purposes. The Calumet Roundtable: A gasoline with Dr. In cats, the tests, found in the literature, to assess the researched cochlear function were composed of auditory evoked potentials and optically evoked action potentials recorded in the round window.
The results demonstrated the effectiveness of pulsed infrared radiation stimulating auditory neurons without causing detectable injury, but a limitation on the effectiveness of the stimulation of spiral ganglion cells by pulsed infrared radiation may be the presence of a significant amount of bone in front of the optical fiber, which would cause light diffraction and scattering Brainstem auditory evoked potentials BAEP are also widely used in hearing research. Besides the advantage related to the functional assessment from the cochlea to the brainstem, it is a noninvasive test. This did not affect the interpretation of the evoked potential, although it caused prolongation in latencies of waves II, III and intervals I-III and IV, without interfering with their identifications Brainstem auditory evoked potentials BAEP were used in Rhesus monkeys in a research that investigated presbycusis There was a connection between age, threshold increase in ABR and decrease in cochlear histopathology of this primate.
The animals studied were between 10 years and three months to 35 years and three months-old, equivalent to 30 to human years. The function of the middle ear of genetic strains of 61 mice was evaluated through tympanometry, otoscopy and analysis of brainstem auditory responses. The combination of these evaluations allows not only the morphological analysis of the middle ear, but also the evaluation of inflammation An alternative experimental model for hearing evaluation is the Caretta caretta turtle.
Auditory evoked potentials and behavioral methods were chosen for measuring audiograms of a captive adult female turtle completely submerged. It was evidenced that the audiograms collected through the behavioral testing and auditory evoked potentials are similar, being the auditory evoked potentials advantageous as they can be conducted in a few hours and with untrained animals Another alternative model, the zebrafish, has already been evaluated by auditory evoked potentials to analyze the death of hair cells induced by the administration of aminoglycosides There is also research in the literature using Locusta migratory locusts for auditory analyses.
These animals are characterized by the responses of the auditory receptor cells in pure tones and by having the tympanal auditory organ located in the first abdominal segment Besides these, rabbits were models in the testing of the effects of mannitol administered topically in the round window after the induction of episodes of repeated ischemia by compression of the internal auditory artery In the literature, there are auditory studies using alternative models.
Birds, such as quails, are often used, since they have advantages such as small size, great egg production and early sexual maturity, being possible to develop transgenic lines of quails in the laboratory Birds and chickens are cited as a study model for the evaluation of ciliary cells, being the birds previously characterized as to the time of regeneration, identification of such precursor cells and cellular processes Zebrafish have been widely used as a model in biological research because of their tolerance to temperature variations, ease of reproduction, identification of genes through mutations, and excellent embryology.
The embryos are large and transparent and can be seen through the chorion during the first twenty-four hours post-fertilization In a descriptive analysis of the ovine ear anatomy, which, among its purposes, was to identify a suitable animal for experimentation and training in otologic surgery, advantages were reported, such as docile behavior, and no need to keep the animal confined in the laboratory. In addition, sheep are widely available due to the economic activities related to meat consumption and wool use The easy manipulation of the guinea pig, by reason of its small size and for being a docile animal, has also been highlighted in the literature 9.
Animals such as cats, dogs and monkeys - in addition to having a different body size from humans - can be difficult to handle in the laboratory, because they are aggressive and susceptible to diseases, can be costly, be less available, and, for being pets, can cause a negative psychosocial effect and meet objection from animal rights agencies Table 3 shows the advantages and disadvantages of using animal models in audiological assessments, by species.
Aging Processes in the Subcortical Auditory System
In relation to the anatomical characteristics of mammals as animal models, there are several advantages regarding their use in audiological evaluations, mainly with reference to anatomical similarities to humans, especially monkeys, although some structures are different or absent. However, in some cases, these animal models require sedation for the tests, bring a negative psychosocial reflex and are more expensive. Economically, small animals are more advantageous because of the smaller volume of food ingested and less space required in the laboratory to maintain animal comfort. Animal size does not seem to be a completely dependent factor in the manipulation of the model, since sheep - although they have a significantly larger size than rats - are easily manipulated in audiological studies, unlike reports related to the possible difficulty in manipulating rats.
As for the anatomical differences between humans and animals, the difference with rats, whose tympanic membrane is semi-occluded, was highlighted. It should be noted that these animals, because of this characteristic, have a greater tendency to otitis media, being a good model for mimicking this pathology. However, in studies whose objective is impaired by the occurrence of otitis, other models should be considered. With respect to the difference between the number of turns in rats and guinea pigs, the authors of the study analyzed suggest that, in research using drugs that influence the cochlea, it would be better to use guinea pigs, since it is the model with a larger number of turns This study does not justify such an assertion, but there may be a relationship between the greater number of turns and a larger basilar membrane size, which would generate a larger spectrum of frequencies and more hair cells.
Despite the absence of an auditory organ and some results that are not applicable in mammalian animal models, zebrafish are widely cited in auditory evaluation analyses, mainly in the assessment of hair cells in the lateral line of this animal model, demonstrating that anatomical characteristics, reproducibility and habitat are relevant for their choice in different assessment methods. As an option to the animal models already established in the literature and commonly used, the occurrence of alternative models was verified.
Some animals have anatomical similarities, others have been chosen for practicality, size, reproducibility and even for the possibility of transgenic reproduction.
Hearing regeneration and regenerative medicine: present and future approaches
If they do not exist, the best techniques proposed should be considered, in order to refine the study and reduce the number of animals used. In order to achieve the objectives proposed in the research, the ideal is that there is a balance between the auditory evaluation method, its feasibility in relation to access to equipment, the presence of a trained professional to evaluate the animal model, and a considerable number of advantages in anatomical and structural terms and greater possibility of generalization for the human auditory system.
It was found, in the literature, a great availability of alternatives for conducting auditory evaluations, such as DPOAE, auditory evoked potentials, scanning electron microscopy SEM and cytocochleograms. These tests, being objective and non-invasive methods, allow the characterization of hearing damage more reliably than behavioral techniques, especially in research with animal models. However, they are limited to the possible use of sedation or anesthesia, which may interfere with wave latency.
Histologically, cellular morphology characterization may facilitate the analysis of the pathophysiology of hearing loss. However, the choice of the animal model interferes with the type of evaluation to be performed. The counting of hair cells in alternative animal models, such as fish, has been performed by methods such as time-lapse imaging, a technique less widespread than optical or electron microscopy, common in mammalian and avian studies.
Variations in studies may be justified by the research objective, as well as by the animal model chosen and the access to equipment.
Therefore, it is essential to know the characteristics of the auditory system of the chosen model, its advantages, disadvantages and limitations in experimental practice. Considering all these aspects, the determination of the number of animals should be as small as possible, respecting, in particular, the standards proposed by RENAMA.
Rodents are still the most commonly used animal models, and the most frequently cited hearing evaluations are distortion product otoacoustic emissions and brainstem auditory evoked potential.
Online Microwave Network Design Using The Scattering Matrix (Artech House Microwave Library)
Albuquerque AAS. Porto Alegre RS : Artmed; Vet Pathol.
- Nuclear Medicine Imaging: An Encyclopedic Dictionary.
- Faith and Force: A Christian Debate about War.
- Practical Plastic Surgery for Nonsurgeons!
- Faculty of Science - Intranet - The University of Sydney.
Cabeza Cuello. Anatomical study of the pigs temporal bone by microdissection. Acta Cir. Vasconcelos CAC. Human evolutionary history: Consequences for the pathogenesis of otitis media. Otolaryngol Head Neck Surg. Soares HB. Silva IA. Rauschecker JP, Tian B.
Mechanisms and streams for processing of "what" and "where" in auditory cortex. Functional assessment of head-eye coordination during driving. Oculomotor tests of otolith function using human centrifugation. Experimental validation of a clinical indicator of utricular function. The role of ocular torsion position in the perception of orientation.
Talking back: Development of the olivocochlear efferent system
The human vestibulo-ocular responses in three dimensions. Generation of vestibuloocular responses to natural head accelerations. Functional organization of the otolithic system of the inner ear.