Hair Cell Regeneration After ATOH1 Case Study

The snail like shape of the cochlear effectively boosts the strength of the vibrations caused by sound, especially for low pitches. When sound waves hit the ear drum, tiny bones in the ear transmit the vibrations to the fluid of the cochlea, where they travel along a tube that winds into a spiral. The tube’s properties gradually change along its length, so the waves grow and then die away, much as an ocean wave travelling towards the shore gets taller and narrower before breaking at the beach.

Twenty-six percent of infants ears demonstrated hearing loss during the first year of life, and 78% of children’s ears demonstrated hearing loss during the study period. Of the children’s ears with hearing loss, 100% had a conductive component and 26% had an additional sensorineural component (mixed hearing loss…Common temporal bone findings included thickening and sclerosis of the

Cochlear implants are biomedical devices that help individuals with severe hearing impairments with auditory sensation. In order to process sound cochlear implants include external and internal components. A microphone, which is part of the external component gathers sound (Petersona, Pisonia, & Miyamoto, 2010). These sound waves from the environment are transferred into electrical signals (Petersen, Gjedde, Wallentin, & Vuust, 2013). The electrical signals are then organized through a series of filters. After this step is completed, the signals are conveyed across the skin to a receiver within the internal components. In the implanted device, further conversion occurs and the signals are delivered to an array of electrodes within the cochlea. Each signal is directed to a specific electrode, this method utilizes tonotopic representation and coding of frequency. Lastly, the electrodes stimulate the auditory nerve (Petersona et al., 2010). These are the main processes involved in the application of cochlear implants. This paper explores some of the current research related to the application of cochlear implants including: language abilities, plasticity and areas for further research.

Hearing loss continues to linger in the elderly population of today’s society. Yet, the onset of hearing loss can occur at any age and at any point in

To do this, the researchers exposed a second group of adult quail to the same hearing-damaging sound as the first and then injected them with radiolabeled thymidine. This allowed researchers to use autoradiography that produce low levels of background issues as well as being able to see 10 to 20 grains over red blood cells. The control birds were still given the injections, however, they were not exposed to the sound. The experimental group experienced the same pattern of damage as the birds in the previous experiment and thymidine was seen over hair cells and support cells in the damaged area. There was no thymidine observed outside of the damaged area. The transition zone of the basilar membrane, where tall and short hair cells are integrated, it seemed that the short cells were more often labeled than the tall cells. Tall cells do not lack the afferent auditory-nerve fiber innervation that is seen in short cells making them a more useful candidate for labeling. The researchers failed to identify location and mechanism of the activation of the precursor cells but remained hopeful that there may exist a way to restore inner ear sensory losses that are caused from injury of hair

The mammalian cochlea is located within the inner ear and is responsible for the transduction of auditory stimuli from an organism’s external environment to the brain. The neurons that mediate this signal transduction are spiral ganglion neurons (SGN), a bipolar cell type with peripheral axons extending to mechanically sensitive hair cells (HC) in the organ of Corti (OC) and central axons that bifurcate and project to the dorsal and ventral cochlear nuclei (DCN, VCN) (Coate, et al., 2013). SGNs are divided into two classes determined by the hair cells to which they project: 90-95% of SGNs innervate inner hair cells (IHCs), whereas the remaining 5-10%

Hair cells are the auditory receptors of the auditory system. Inner hair cells are those located between the modiolus and the rods of the Corti. They are positioned with 3500 in one row. The outer hair cells on the other hand are located farther out than the rods of Corti and are arranged in three rows of a total of 15,000 to 20,000 hair cells. The stereocilia extend with their tips ending at either the outer hair cells’ gelatinous substance or below the tectorial membrane in the inner hair cells. Outer hair cells are found only in mammals and function by vibtrating to produce a sound in our ears, while the inner hair cells are geared towards a release of neurotransmitter to the synapses which allows them to react quickly to any mechanical

It was thought earlier that stem cells stimpulates hairs to regrow after they fall out, but the scientists found that Tregs are the real effeiecnt factor behind the process.

They found that the canonical Notch pathway is not active to any significant degree in the

The neural processes required to hear a phone ring may surprise some people. The neuron’s cell body (the part of the neuron which contains the nucleus) contains branch-like structures known as dendrites, which receive information from the axon—a long tail-like portion of the neuron. This information then travels to other neurons via chemicals called neurotransmitters (Pastorino & Doyle-Portile, 2015). The axon is coated by a wax-like substance called myelin, composed of segments known as myelin sheaths. Corrosion of the myelin sheaths may adversely affect a sensory input, in this case

The hair follicle is maintained by continuous cycles of generation and degeneration, which are highly controlled by molecular signals that induce cell proliferation, differentiation, and death. Wnt, BMP, SHH, and Notch are a few of the signaling pathways that have been involved in regulating the hair cycle [28]. The hair cycle is divided into three stages, which are telogen, anagen, and catagen. Telogen is a quiescent period where the dermal papilla rests under the bulge stem cell compartment [14]. The dermal papilla is a group of mesenchymal cells that control hair follicle development and serve as a stem cell reservoir [11]. After receiving the necessary signals, the follicle enters the active state of hair growth, anagen. During this stage,

Cisplatin is a platinum-based chemotherapeutic agent with proven efficacy against solid tumors. However, the clinical use of cisplatin is limited by the development of permanent hearing loss in cancer patients. There is currently no drug approved by the US Food and Drug Administration for cisplatin-induced hearing loss (1, 2). Multiple studies have shown that cisplatin profoundly damages outer hair cells (OHCs) present in the hook region, basal and middle turns of the cochlea (3, 4) with relative sparing of inner hair cells (IHCs) in these regions. Other regions of the cochlea such as the spiral ligament (SL), stria vascularis (SV) and spiral ganglion neuron (SGN) are also susceptible to cisplatin-induced damage (5-9).

An adult stem cell’s niche is responsible for the preservation of the stem cell’s undifferentiated state through either intrinsic or extrinsic expression of specific proteins. Hair follicle stem cells are responsible for not only its self-renewal but also in the production of rapidly multiplying cells. The stem cells of the hair follicle are for temporary increase in cells, and are created by the differentiation of hair follicle stem cells. The focus of this essay will be to analyze a specific protein within the hair follicle stem cell BMP, bone morphogenetic proteins. Through intrinsic expression, Bone morphogenetic proteins (BMPs) are able to function in multi levels and are in charge for the transforming growth factor beta (TGFbeta). These proteins are crucial for the maintenance and the proliferation of hair follicle stem cells. Bone morphogentic proteins have the ability to affect other molecules that are part of the niche, which boosts or limits particular cellular functions to the needs of the human body and niche. This paper will discuss two experiments conducted that exhibit the function of BMP. One experiment will examine the results of BMP deletion in genetically modified dermal papilla cells patched onto mice that had no hair. The second scientific experiment will demonstrate the effects of excess and limited quantities of BMP expression in vitro on isolated chick otic vesicles. From these experiments scientists can foresee the future in developing various

The ear is an extraordinary human organ that many people take for granted until it doesn’t function. It is the only device that allows the human to hear sounds in their environment. The ear is made up of many parts that distinguish various sounds through different means. The ear anatomy and physiology along with how sound waves are transmitted into meaningful sounds will help one understand how hearing loss occurs.

In order to observe the dependent correlation between Lhx2 transcription factors and Lgr5 cells in hair regeneration after a wound, laboratory mice, Mus musculus, will be utilized as our model system. Mus musculus will be our model system because mice are one of the few animals most genetically, biologically, and behaviorally similar to humans.