Temporal Bone Studies of the Human Peripheral Vestibular System

2000 ◽  
Vol 109 (5_suppl) ◽  
pp. 3-13 ◽  
Author(s):  
Saumil N. Merchant ◽  
Kojiro Tsuji ◽  
Conrad Wall ◽  
Luis Velázquez-Villaseñor ◽  
Robert J. Glynn ◽  
...  
Keyword(s):  
Hair Cell ◽  
Hair Cells ◽  
Type I ◽  
Type Ii ◽  
Sense Organs ◽  
Age Related ◽  
The Mean ◽  
Cell Densities ◽  
Temporal Bones ◽  
Total Type

Quantitative studies of the vestibular system with serially sectioned human temporal bones have been limited because of difficulty in distinguishing hair cells from supporting cells and type I from type II hair cells. In addition, there is only a limited amount of normative data available regarding vestibular hair cell counts in humans. In this study, archival temporal bone sections were examined by Nomarski (differential interference contrast) microscopy, which permitted visualization of the cuticular plate and stereociliary bundle so as to allow unambiguous identification of hair cells. The density of type I, type II, and total numbers of vestibular hair cells in each of the 5 sense organs was determined in a set of 67 normal temporal bones that ranged from birth through 100 years of age. The mean total densities at birth were 76 to 79 cells per 0.01 mm2 in the cristae, 68 cells per 0.01 mm2 in the utricle, and 61 cells per 0.01 mm2 in the saccule. The ratio of type I to type II hair cells at birth was 2.4:1 in the cristae and 1.3:1 in the maculae. There was a highly significant age-related decline in all sense organs for total, type I, and type II hair cell densities that was best fit by a linear regression model. The cristae lost type I cells with advancing age at a significantly greater rate than the maculae, whereas age-related losses for type II cells occurred at the same rate for all 5 sense organs. Hair cell densities in the cristae were significantly higher at the periphery than at the center. There were no significant sex or interaural differences for any of the counts. Mathematical models were developed to calculate the mean and 95% prediction intervals for the total, type I, and type II hair cell densities in each sense organ on the basis of age. There was overall good agreement between the hair cell densities determined in this study and those reported by others using surface preparation techniques. Our data and related models will serve as a normative database that will be useful for comparison to counts made from subjects with known vestibular disorders.

Temporal Bone Studies of the Human Peripheral Vestibular System

2000 ◽  
Vol 109 (5_suppl) ◽  
pp. 20-25 ◽  
Author(s):  
Kojiro Tsuji ◽  
Steven D. Rauch ◽  
Conrad Wall ◽  
Luis Velázquez-Villaseñor ◽  
Robert J. Glynn ◽  
...  
Keyword(s):  
Hair Cell ◽  
Hair Cells ◽  
Ganglion Cells ◽  
Significant Loss ◽  
Small Sample ◽  
Type I ◽  
Type Ii ◽  
Vestibular Hair Cells ◽  
Scarpa's Ganglion ◽  
Temporal Bones

Quantitative assessments of vestibular hair cells and Scarpa's ganglion cells were performed on 17 temporal bones from 10 individuals who had well-documented clinical evidence of aminoglycoside ototoxicity (streptomycin, kanamycin, and neomycin). Assessment of vestibular hair cells was performed by Nomarski (differential interference contrast) microscopy. Hair cell counts were expressed as densities (number of cells per 0.01 mm2 surface area of the sensory epithelium). The results were compared with age-matched normal data. Streptomycin caused a significant loss of both type I and type II hair cells in all 5 vestibular sense organs. In comparing the ototoxic effect on type I versus type II hair cells, there was greater type I hair cell loss for all 3 cristae, but not for the maculae. The vestibular ototoxic effects of kanamycin appeared to be similar to those of streptomycin, but the small sample size precluded definitive conclusions from being made. Neomycin did not cause loss of vestibular hair cells. Within the limits of this study (maximum postototoxicity survival time of 12 months), there was no significant loss of Scarpa's ganglion cells for any of the 3 drugs. The findings have implications in several clinical areas, including the correlation of vestibular test results to pathological findings, the rehabilitation of patients with vestibular ototoxicity, the use of aminoglycosides to treat Meniere's disease, and the development of a vestibular prosthesis.

Vestibular Type I and Type II Hair Cells. 1: Morphometric Identification in the Pigeon and Gerbil

1997 ◽  
Vol 7 (5) ◽  
pp. 393-406
Author(s):  
Anthony J. Ricci ◽  
Katherine J. Rennie ◽  
Stephen L. Cochran ◽  
Golda A. Kevetter ◽  
Manning J. Correia
Keyword(s):  
Hair Cell ◽  
Hair Cells ◽  
Cell Types ◽  
Type I ◽  
Type Ii ◽  
Body Width ◽  
Fixed Tissue ◽  
Neck Width ◽  
I Cells ◽  
Plate Width

Classically, type I and type II vestibular hair cells have been defined by their afferent innervation patterns. Little quantitative information exists on the intrinsic morphometric differences between hair cell types. Data presented here define a quantitative method for distinguishing hair cell types based on the morphometric properties of the hair cell’s neck region. The method is based initially on fixed histological sections, where hair cell types were identified by innervation pattern, type I cells having an afferent calyx. Cells were viewed using light microscopy, images were digitized, and measurements were made of the cell body width, the cuticular plate width, and the neck width. A plot of the ratio of the neck width to cuticular plate width (NPR) versus the ratio of the neck width to the body width (NBR) established four quadrants based on the best separation of type I and type II hair cells. The combination of the two variables made the accuracy of predicting either type I or type II hair cells greater than 90%. Statistical cluster analysis confirmed the quadrant separation. Similar analysis was performed on dissociated hair cells from semicircular canal, utricle, and lagena, giving results statistically similar to those of the fixed tissue. Additional comparisons were made between fixed tissue and isolated hair cells as well as across species (pigeon and gerbil) and between end organs (semicircular canal, utricle, and lagena). In each case, the same morphometric boundaries could be used to establish four quadrants, where quadrant 1 was predominantly type I cells and quadrant 3 was almost exclusively type II hair cells. The quadrant separations were confirmed statistically by cluster analysis. These data demonstrate that there are intrinsic morphometric differences between type I and type II hair cells and that these differences can be maintained when the hair cells are dissociated from their respective epithelia.

scholarly journals Unmyelinated type II afferent neurons report cochlear damage

2015 ◽  
Vol 112 (47) ◽  
pp. 14723-14727 ◽  
Author(s):  
Chang Liu ◽  
Elisabeth Glowatzki ◽  
Paul Albert Fuchs
Keyword(s):  
Hair Cell ◽  
Hair Cells ◽  
Outer Hair Cell ◽  
Cell Damage ◽  
Large Diameter ◽  
Outer Hair Cells ◽  
Type I ◽  
Type Ii ◽  
Inner Hair Cell ◽  
Hair Cell Damage

In the mammalian cochlea, acoustic information is carried to the brain by the predominant (95%) large-diameter, myelinated type I afferents, each of which is postsynaptic to a single inner hair cell. The remaining thin, unmyelinated type II afferents extend hundreds of microns along the cochlear duct to contact many outer hair cells. Despite this extensive arbor, type II afferents are weakly activated by outer hair cell transmitter release and are insensitive to sound. Intriguingly, type II afferents remain intact in damaged regions of the cochlea. Here, we show that type II afferents are activated when outer hair cells are damaged. This response depends on both ionotropic (P2X) and metabotropic (P2Y) purinergic receptors, binding ATP released from nearby supporting cells in response to hair cell damage. Selective activation of P2Y receptors increased type II afferent excitability by the closure of KCNQ-type potassium channels, a potential mechanism for the painful hypersensitivity (that we term “noxacusis” to distinguish from hyperacusis without pain) that can accompany hearing loss. Exposure to the KCNQ channel activator retigabine suppressed the type II fiber’s response to hair cell damage. Type II afferents may be the cochlea’s nociceptors, prompting avoidance of further damage to the irreparable inner ear.

scholarly journals Correlation between visual acuity, external limiting membrane and photoreceptor status in patients with neovascular age-related macular degeneration treated with bevacizumab

2017 ◽  
Vol 74 (9) ◽  
pp. 849-853
Author(s):  
Dragana Ristic ◽  
Miroslav Vukosavljevic ◽  
Marko Kontic ◽  
Petar Ristic ◽  
Dubravko Bokonjic ◽  
...  
Keyword(s):  
Visual Acuity ◽  
Age Related Macular Degeneration ◽  
Type I ◽  
Type Ii ◽  
External Limiting Membrane ◽  
Corrected Visual Acuity ◽  
Age Related ◽  
Number Of Patients ◽  
The Mean ◽  
Best Corrected Visual Acuity

Background/Aim. The integrity of outer retinal structures, primarily the photoreceptor layer, is important because of its direct correlation with visual acuity. The aim of this study was to investigate the correlation between best-corrected visual acuity (BCVA), the foveal photoreceptorinner segment/outer segment (IS/OS) junction and external limiting membrane (ELM) in patients with neovascular age-related macular degeneration (NVAMD) after the treatment with bevacizumab, as well as the correlation between the above-mentioned parameters and different types of neovascular membrane, classified by fluorescein angiography (FA). Methods. The study included 82 patients with NVAMD, treated with intravitreal bevacizumab. All patients underwent a basic ophthalmological examination, FA and optical coherence tomography (OCT). Based on the results of FA, all the patients were divided into two main groups ? type I (the occult and minimally classic) and type II (classic and predominantly classic) of the choroidal neovascular membrane (CNV). The OCT images revealed either the presence or the absence of IS/OS and ELM. Results. After the treatment, the mean best corrected visual acuity improved significantly in both groups (p < 0.01). Preserved IS/OS and ELM were registered in a smaller number of patients as compared to the condition before the treatment (p < 0.01). After the treatment, the mean BCVA was significantly better in patients with preserved IS/OS and ELM (p < 0.01). In addition, we registered a higher number of patients with preserved ELM in the first group than in the second group (p < 0.01), whereas there was no significant difference in the integrity of IS/OS between the groups (p > 0.05). Conclusion. The patients with preserved IS/OS and ELM achieved better final visual acuity as compared to the patients without preserved IS/OS and ELM. In our patients, the absence of IS/OS and ELM were more frequent in type II (classic and predominantly classic) CNV than in type I (the occult and minimally classic) CNV.

Synaptic ribbon plasticity, ribbon size and potential regulatory mechanisms in utricular and saccular maculae

2005 ◽  
Vol 15 (1) ◽  
pp. 17-30 ◽  
Author(s):  
Muriel D. Ross ◽  
Joseph Varelas
Keyword(s):  
Hair Cells ◽  
Smooth Endoplasmic Reticulum ◽  
Type I ◽  
Synaptic Ribbons ◽  
Type Ii ◽  
Synaptic Ribbon ◽  
Utricular Macula ◽  
Ribbon Synapses ◽  
New Finding ◽  
The Mean

The mean number of synaptic ribbons in type II hair cells of the rat utricular macula increased significantly in weightlessness. In contrast, ribbon synapses of saccular type I hair cells displayed a significant decline early inflight and postflight, and a late numerical overshoot. Further study indicated that the saccular macula had less ultrastructural complexly than the utricular. Additionally, synaptic ribbons were statistically larger in type II hair cells of both maculae, apparently a locus-related scaling effect. A major new finding is that mitochondria in calyces and collateral terminals were linked to vesicles, tubules of smooth endoplasmic reticulum and cell membranes by filaments, forming mitochondrial complexes (MCs). MCs predominated basally in the calyx where calyceal/type I hair cell borders were bound by filaments; at calyceal invaginations of type I hair cells; in calyces and collaterals near synaptic ribbon sites; and in collaterals near reciprocal synapses. MCs may participate in feedback mechanisms at these locations to help regulate synaptic ribbon activity and plasticity in altered gravitational environments.

Architecture of the Mouse Utricle: Macular Organization and Hair Bundle Heights

2008 ◽  
Vol 99 (2) ◽  
pp. 718-733 ◽  
Author(s):  
A. Li ◽  
J. Xue ◽  
E. H. Peterson
Keyword(s):  
Hair Cell ◽  
Hair Cells ◽  
Quantitative Data ◽  
Posterior Margin ◽  
Adult Mouse ◽  
Type I ◽  
Type Ii ◽  
Cell Type ◽  
Vestibular Hair Cells ◽  
Utricular Macula

Hair bundles are critical to mechanotransduction by vestibular hair cells, but quantitative data are lacking on vestibular bundles in mice or other mammals. Here we quantify bundle heights and their variation with macular locus and hair cell type in adult mouse utricular macula. We also determined that macular organization differs from previous reports. The utricle has ∼3,600 hair cells, half on each side of the line of polarity reversal (LPR). A band of low hair cell density corresponds to a band of calretinin-positive calyces, i.e., the striola. The relation between the LPR and the striola differs from previous reports in two ways. First, the LPR lies lateral to the striola instead of bisecting it. Second, the LPR follows the striolar trajectory anteriorly, but posteriorly it veers from the edge of the striola to reach the posterior margin of the macula. Consequently, more utricular bundles are oriented mediolaterally than previously supposed. Three hair cell classes are distinguished in calretinin-stained material: type II hair cells, type ID hair cells contacting calretinin-negative (dimorphic) afferents, and type IC hair cells contacting calretinin-positive (calyceal) afferents. They differ significantly on most bundle measures. Type II bundles have short stereocilia. Type IC bundles have kinocilia and stereocilia of similar heights, i.e., KS ratios (ratio of kinocilium to stereocilia heights) ∼1, unlike other receptor classes. In contrast to these class-specific differences, bundles show little regional variation except that KS ratios are lowest in the striola. These low KS ratios suggest that bundle stiffness is greater in the striola than in the extrastriola.

Single-Channel L-Type Ca2+ Currents in Chicken Embryo Semicircular Canal Type I and Type II Hair Cells

2006 ◽  
Vol 96 (2) ◽  
pp. 602-612 ◽  
Author(s):  
Valeria Zampini ◽  
Paolo Valli ◽  
Giampiero Zucca ◽  
Sergio Masetto
Keyword(s):  
Hair Cells ◽  
Type I ◽  
Ca Channel ◽  
Type Ii ◽  
Ca Channels ◽  
Channel Activity ◽  
Average Slope ◽  
Patch Pipette ◽  
The Mean ◽  
Channel Properties

Few data are available concerning single Ca channel properties in inner ear hair cells and particularly none in vestibular type I hair cells. By using the cell-attached configuration of the patch-clamp technique in combination with the semicircular canal crista slice preparation, we determined the elementary properties of voltage-dependent Ca channels in chicken embryo type I and type II hair cells. The pipette solutions included Bay K 8644. With 70 mM Ba2+ in the patch pipette, Ca channel activity appeared as very brief openings at −60 mV. Ca channel properties were found to be similar in type I and type II hair cells; therefore data were pooled. The mean inward current amplitude was −1.3 ± 0.1 (SD) pA at − 30 mV ( n = 16). The average slope conductance was 21 pS ( n = 20). With 5 mM Ba2+ in the patch pipette, very brief openings were already detectable at −80 mV. The mean inward current amplitude was −0.7 ± 0.2 pA at −40 mV ( n = 9). The average slope conductance was 11 pS ( n = 9). The mean open time and the open probability increased significantly with depolarization. Ca channel activity was still present and unaffected when ω-agatoxin IVA (2 μM) and ω-conotoxin GVIA (3.2 μM) were added to the pipette solution. Our results show that types I and II hair cells express L-type Ca channels with similar properties. Moreover, they suggest that in vivo Ca2+ influx might occur at membrane voltages more negative than −60 mV.

Differences Between Stereocilia Numbers on Type I and Type II Vestibular Hair Cells

2004 ◽  
Vol 92 (5) ◽  
pp. 3153-3160 ◽  
Author(s):  
W. J. Moravec ◽  
E. H. Peterson
Keyword(s):  
Hair Cell ◽  
Hair Cells ◽  
Direct Evidence ◽  
Cell Types ◽  
Type I ◽  
Type Ii ◽  
Functional Roles ◽  
Vestibular Hair Cells ◽  
Mechanoelectric Transduction ◽  
Bundle Structure

A major outstanding goal of vestibular neuroscience is to understand the distinctive functional roles of type I and type II hair cells. One important question is whether these two hair cell types differ in bundle structure. To address this, we have developed methods to characterize stereocilia numbers on identified type I and type II hair cells in the utricle of a turtle, Trachemys scripta. Our data indicate that type I hair cells, which occur only in the striola, average 95.9 ±16.73 (SD) stereocilia per bundle. In contrast, striolar type II hair cells have 59.9 ± 8.98 stereocilia, and type II hair cells in the adjacent extrastriola average 44.8 ± 10.82 stereocilia. Thus type I hair cells have the highest stereocilia counts in the utricle. These results provide the first direct evidence that type I hair cells have significantly more stereocilia than type II hair cells, and they suggest that the two hair cell types may differ in bundle mechanics and peak mechanoelectric transduction currents.

scholarly journals Electromyographic activation patterns during swallowing in older adults

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jin Young Ko ◽  
Hayoung Kim ◽  
Joonyoung Jang ◽  
Jun Chang Lee ◽  
Ju Seok Ryu
Keyword(s):  
Older Adults ◽  
Viscous Fluid ◽  
Muscle Activation ◽  
Fatty Infiltration ◽  
Liquid Volume ◽  
Type I ◽  
Type Ii ◽  
Activation Patterns ◽  
Muscle Activation Patterns ◽  
Age Related

AbstractAge-related weakness due to atrophy and fatty infiltration in oropharyngeal muscles may be related to dysphagia in older adults. However, little is known about changes in the oropharyngeal muscle activation pattern in older adults. This was a prospective and experimental study. Forty healthy participants (20 older [> 60 years] and 20 young [< 60 years] adults) were enrolled. Six channel surface electrodes were placed over the bilateral suprahyoid (SH), bilateral retrohyoid (RH), thyrohyoid (TH), and sternothyroid (StH) muscles. Electromyography signals were then recorded twice for each patient during swallowing of 2 cc of water, 5 cc of water, and 5 cc of a highly viscous fluid. Latency, duration, and peak amplitude were measured. The activation patterns were the same, in the order of SH, TH, and StH, in both groups. The muscle activation patterns were classified as type I and II; the type I pattern was characterized by a monophasic shape, and the type II comprised a pre-reflex phase and a main phase. The oropharyngeal muscles and SH muscles were found to develop a pre-reflex phase specifically with increasing volume and viscosity of the swallowed fluid. Type I showed a different response to the highly viscous fluid in the older group compared to that in the younger group. However, type II showed concordant changes in the groups. Therefore, healthy older people were found to compensate for swallowing with a pre-reflex phase of muscle activation in response to increased liquid volume and viscosity, to adjust for age-related muscle weakness.

scholarly journals Minimal Invasive Surgery for Gastroesophageal Reflux Disease and Hiatus Hernia—Our Experience: A Case Series with Review of Literature

2021 ◽  
Author(s):  
Rafique Umer Harvitkar ◽  
Abhijit Joshi
Keyword(s):  
Retrospective Study ◽  
Gastroesophageal Reflux Disease ◽  
Gastroesophageal Reflux ◽  
Operating Time ◽  
Type I ◽  
Type Ii ◽  
The Mean ◽  
Gerd Symptoms

Abstract Introduction Laparoscopic fundoplication (LF) has almost completely replaced the open procedure performed for gastroesophageal reflux disease (GERD) and hiatus hernia (HH). Several studies have suggested that long-term results with surgery for GERD are better than a medical line of management. In this retrospective study, we outline our experience with LF over 10 years. Also, we analyze the factors that would help us in better patient selection, thereby positively affecting the outcomes of surgery. Patients and Methods In this retrospective study, we identified 27 patients (14 females and 13 males) operated upon by a single surgeon from 2010 to 2020 at our institution. Out of these, 25 patients (12 females and 13 males) had GERD with type I HH and 2 (both females) had type II HH without GERD. The age range was 24 to 75 years. All patients had undergone oesophago-gastro-duodenoscopy (OGD scopy). A total of 25 patients had various degrees of esophagitis. Two patients had no esophagitis. These patients were analyzed for age, sex, symptoms, preoperative evaluation, exact procedure performed (Nissen’s vs. Toupet’s vs. cruroplasty + gastropexy), morbidity/mortality, and functional outcomes. They were also reviewed to examine the length of stay, length of procedure, complications, and recurrent symptoms on follow-up. Symptoms were assessed objectively with a score for six classical GERD symptoms preoperatively and on follow-up at 1-, 4- and 6-weeks postsurgery. Further evaluation was performed after 6 months and then annually for 2 years. Results 14 females (53%) and 13 males (48%) with a diagnosis of GERD (with type I HH) and type II HH were operated upon. The mean age was 46 years (24–75 years) and the mean body mass index (BMI) was 27 (18–32). The range of duration of the preoperative symptoms was 6 months to 2 years. The average operating time dropped from 130 minutes for the first 12 cases to 90 minutes for the last 15 cases. The mean hospital stay was 3 days (range: 2–4 days). In the immediate postoperative period, 72% (n = 18) of the patients reported improvement in the GERD symptoms, while 2 (8%) patients described heartburn (grade I, mild, daily) and 1 (4%) patient described bloating (grade I, daily). A total of 5 patients (20%) reported mild dysphagia to solids in the first 2 postoperative weeks. These symptoms settled down after 2 to 5 weeks of postoperative proton-pump inhibitor (PPI) therapy and by adjusting consistency of oral feeds. There was no conversion to open, and we observed no perioperative mortality. There were no patients who underwent redo surgeries in the series. Conclusion LF is a safe and highly effective procedure for a patient with symptoms of GERD, and it gives long-term relief from the symptoms. Stringent selection criteria are necessary to optimize the results of surgery. Experience is associated with a significant reduction of operating time.

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