Unilateral Adaptation of the Human Angular Vestibulo-Ocular Reflex

A recent study showed that the angular vestibulo-ocular reflex (VOR) can be better adaptively increased using an incremental retinal image velocity error signal compared with a conventional constant large velocity-gain demand (×2). This finding has important implications for vestibular rehabilitation that seeks to improve the VOR response after injury. However, a large portion of vestibular patients have unilateral vestibular hypofunction, and training that raises their VOR response during rotations to both the ipsilesional and contralesional side is not usually ideal. We sought to determine if the vestibular response to one side could selectively be increased without affecting the contralateral response. We tested nine subjects with normal vestibular function. Using the scleral search coil and head impulse techniques, we measured the active and passive VOR gain (eye velocity / head velocity) before and after unilateral incremental VOR adaptation training, consisting of self-generated (active) head impulses, which lasted ∼15 min. The head impulses consisted of rapid, horizontal head rotations with peak-amplitude 15 ^o, peak-velocity 150 ^o/s and peak-acceleration 3,000 ^o/s². The VOR gain towards the adapting side increased after training from 0.92 ± 0.18 to 1.11 ± 0.22 (+22.7 ± 20.2 %) during active head impulses and from 0.91 ± 0.15 to 1.01 ± 0.17 (+11.3 ± 7.5 %) during passive head impulses. During active impulses, the VOR gain towards the non-adapting side also increased by ∼8 %, though this increase was ∼70 % less than to the adapting side. A similar increase did not occur during passive impulses. This study shows that unilateral vestibular adaptation is possible in humans with a normal VOR; unilateral incremental VOR adaptation may have a role in vestibular rehabilitation. The increase in passive VOR gain after active head impulse adaptation suggests that the training effect is robust.     

Enhanced Vestibulo-ocular Reflex to Electrical Vestibular Stimulation in Meniere’s Disease

Meniere’s disease is characterized by sporadic episodes of vertigo, nystagmus, fluctuating sensorineural hearing loss, tinnitus and aural pressure. Since Meniere’s disease can affect different regions of the vestibular labyrinth, we investigated if electrical vestibular stimulation (EVS) which excites the entire vestibular labyrinth may be useful to reveal patchy endorgan pathology. We recorded three-dimensional electrically evoked vestibulo-ocular reflex (eVOR) to transient EVS using bilateral, bipolar 100-ms current steps at intensities of 0.9, 2.5, 5.0, 7.5 and 10.0 mA with dual-search coils in 12 unilateral Meniere’s patients. Their results were compared to 17 normal subjects. Normal eVOR had tonic and phasic spatiotemporal properties best described by the torsional component, which was four times larger than horizontal and vertical components. At EVS onset and offset of 8.9 ms latency, there were phasic eVOR initiation (M = 1,267 °/s²) and cessation (M = −1,675 °/s²) acceleration pulses, whereas during the constant portion of the EVS, there was a maintained tonic eVOR (M = 9.1 °/s) at 10 mA. However in Meniere’s disease, whilst latency of EVS onset and offset was normal at 9.0 ms, phasic eVOR initiation (M = 1,720 °/s²) and cessation (M = −2,523 °/s²) were enlarged at 10 mA. The initiation profile was a bimodal response, whilst the cessation profile frequently did not return to baseline. The tonic eVOR (M = 20.5 °/s) exhibited a ramped enhancement of about twice normal at 10 mA. Tonic eVOR enhancement was present for EVS >0.9 mA and disproportionately enhanced the torsional, vertical and horizontal components. These eVOR abnormalities may be a diagnostic indicator of Meniere’s disease and may explain the vertigo attacks in the presence of declining mechanically evoked vestibular responses.     

Experimental Measurement of Utricle System Dynamic Response to Inertial Stimulus

The membranous utricle sac of the red-eared turtle was mounted in a piezoelectric actuated platform mounted on the stage of a light microscope. The piezoelectric actuator oscillated the base of the neuroepithelium along a linear axis. Displacements were in the plane of the utricle and consisted of a linear sinusoidal-sweep signal starting at 0 and increasing to 500 Hz over 5 s. This inertial stimulus caused measurable shear displacement of the otoconial layer’s dorsal surface, resulting in shear deformation of the gelatinous and column filament layers. Displacements of the otoconial layer and a reference point on the neuroepithelium were filmed at 2,000 frames/s with a high-speed video camera during oscillations. Image registration was performed on the video to track displacements with a resolution better than 15 nm. The displacement waveforms were then matched to a linear second-order model of the dynamic system. The model match identified two system mechanical parameters—the natural circular frequency ω_n and the damping ratio ζ—that characterized the utricle dynamic response. The median values found for the medial-lateral axis on 20 utricles with 95 % confidence intervals in parenthesis were as follows: ω_n = 374 (353, 396) Hz and ζ = 0.50 (0.47, 0.53). The anterior-posterior axis values were not significantly different: ω_n = 409 (390, 430) Hz and ζ = 0.53 (0.48, 0.57). The results have two relevant and significant dynamic system findings: (1) a higher than expected natural frequency and (2) significant under damping. Previous to this study, utricular systems were treated as overdamped and with natural frequencies much lower that measured here. Both of these system performance findings result in excellent utricle time response to acceleration stimuli and a broad frequency bandwidth up to 100 Hz. This study is the first to establish the upper end of this mechanical system frequency response of the utricle in any animal.     

A Genome-Wide Association Study of Chronic Otitis Media with Effusion and Recurrent Otitis Media Identifies a Novel Susceptibility Locus on Chromosome 2

Chronic otitis media with effusion (COME) and recurrent otitis media (ROM) have been shown to be heritable, but candidate gene and linkage studies to date have been equivocal. Our aim was to identify genetic susceptibility factors using a genome-wide association study (GWAS). We genotyped 602 subjects from 143 families with 373 COME/ROM subjects using the Illumina Human CNV370-Duo DNA Bead Chip (324,748 SNPs). We carried out the GWAS scan and imputed SNPs at the regions with the most significant associations. Replication genotyping in an independent family-based sample was conducted for 53 SNPs: the 41 most significant SNPs with P < 10⁻⁴ and 12 imputed SNPs with P < 10⁻⁴ on chromosome 15 (near the strongest signal). We replicated the association of rs10497394 (GWAS discovery P = 1.30 × 10⁻⁵) on chromosome 2 in the independent otitis media population (P = 4.7 × 10⁻⁵; meta-analysis P = 1.52 × 10⁻⁸). Three additional SNPs had replication P values < 0.10. Two were on chromosome 15q26.1 including rs1110060, the strongest association with COME/ROM in the primary GWAS (P = 3.4 ×10⁻⁷) in KIF7 intron 7 (P = 0.072), and rs10775247, a non-synonymous SNP in TICRR exon 2 (P = 0.075). The third SNP rs386057 was on chromosome 5 in TPPP intron 1 (P = 0.045). We have performed the first GWAS of COME/ROM and have identified a SNP rs10497394 on chromosome 2 is significantly associated with COME/ROM susceptibility. This SNP is within a 537 kb intergenic region, bordered by CDCA7 and SP3. The genomic and functional significance of this newly identified locus in COME/ROM pathogenesis requires additional investigation.     

梅尼埃病前庭功能分级的探讨

目的 建立一种新的梅尼埃病患者前庭功能分级方法,初步探索其临床意义及与梅尼埃病听力分期的相关性。 方法 收集112例单侧梅尼埃病患者资料,所有患者均完成包括纯音测听、cVEMP、oVEMP、vHIT以及冷热试验检查。冷热试验和vHIT的结果中任一项异常均视为半规管功能异常。cVEMP结果异常视为球囊功能异常,oVEMP结果异常视为椭圆囊功能异常。球囊、椭圆囊、半规管功能均正常的患者为前庭功能I级,球囊、椭圆囊、半规管功能其中1项异常者为前庭功能Ⅱ级,2项异常者为前庭功能Ⅲ级,3项均异常者为前庭功能Ⅳ级。 结果 根据听力分期,符合入组标准的95例梅尼埃病患者中Ⅰ期13例、Ⅱ期13例、Ⅲ期52例、Ⅳ期17例。患耳平均听阈为(51.86±21.70)dB HL。前庭功能检测结果cVEMP异常率63.2%,oVEMP24异常率74.7%,vHIT异常率33.7%,冷热试验异常率52.6%。前庭功能分级Ⅰ级9例、Ⅱ级28例、Ⅲ级39例、Ⅳ级19例。前庭功能分级与患者的听力差异有统计学意义(P<0.01, r=0.35)。前庭功能分级与患者梅尼埃病分期差异有统计学意义(P<0.01, r=0.35)。前庭功能分级与患者的病程差异有统计学意义(P=0.02, r=0.24)。前庭功能分级与患者的年龄差异无统计学意义(P=0.084)。 结论 梅尼埃病患者随着病程的进展,耳石器功能和半规管功能检测异常率会逐渐增加。通过对球囊、椭圆囊、半规管低频和高频功能的精细化检测,能够对梅尼埃病患者前庭功能进行精准评估。听力分期与前庭功能分级的同步评估能够反映患者疾病的进展状态,同时能够对患者治疗方案的选择和术后康复的预判起到参考作用。     

Chemical composition of Galla chinensis extract and the effect of its main component(s) on the prevention of enamel demineralization in vitro

To determine the chemical composition of Galla chinensis extract(GCE) by several analysis techniques and to compare the efficacy of GCE and its main component(s) in inhibition of enamel demineralization,for the development of future anticaries agents,main organic composition of GCE was qualitatively determined by liquid chromatography-time of flight-mass spectrometry(LC-TOF-MS) and quantified by high-performance liquid chromatography-diode array detector(HPLC-DAD).Inorganic ions were tested by inductively coupled plasma-atomic emission spectroscopy and F was especially measured by ion chromatography.Then,bovine enamel blocks were randomly divided into four treatment groups and were subjected to a pH-cycling regime for 12 times.Each cycle included 5-min applications with one of four treatments:4 g?L 21 GCE solution,4 g?L 21 gallic acid(GA) solution,1 g?L 21 NaF solution(positive control),deionized water(DDW,negative control),and then 60-min application in pH 5.0 acidic buffer and 5-min application in neutral buffer.Acidic buffers were retained for calcium analysis.The main organic composition of GCE were GA and its isomer,and,to a lesser extent,small molecule gallotannins.The content of GA in GCE was 71.3%60.2%(w/w).Inorganic ions were present in various amounts,of which Ca was(13662.82) mg?g 21,and Zn was(6.860.1) mg?g 21.No F was detected in GCE.In pH cycling,GA showed an effect similar to GCE in inhibiting enamel demineralization(P.0.05).GA was found to be the main effective,demineralization inhibiting component of GCE and could be a promising agent for the development of anticaries agents.     

Sensory innervation around immediately vs. delayed loaded implants:a pilot study

Although neurophysiological and psychophysical proof of osseoperception is accumulating, histomorphometric evidence for the neural mechanisms of functional compensation following immediate and delayed ...     

Basilar Membrane and Tectorial Membrane Stiffness in the CBA/CaJ Mouse

The mouse has become an important animal model in understanding cochlear function. Structures, such as the tectorial membrane or hair cells, have been changed by gene manipulation, and the resulting effect on cochlear function has been studied. To contrast those findings, physical properties of the basilar membrane (BM) and tectorial membrane (TM) in mice without gene mutation are of great importance. Using the hemicochlea of CBA/CaJ mice, we have demonstrated that tectorial membrane (TM) and basilar membrane (BM) revealed a stiffness gradient along the cochlea. While a simple spring mass resonator predicts the change in the characteristic frequency of the BM, the spring mass model does not predict the frequency change along the TM. Plateau stiffness values of the TM were 0.6 ± 0.5, 0.2 ± 0.1, and 0.09 ± 0.09 N/m for the basal, middle, and upper turns, respectively. The BM plateau stiffness values were 3.7 ± 2.2, 1.2 ± 1.2, and 0.5 ± 0.5 N/m for the basal, middle, and upper turns, respectively. Estimations of the TM Young’s modulus (in kPa) revealed 24.3 ± 25.2 for the basal turns, 5.1 ± 4.5 for the middle turns, and 1.9 ± 1.6 for the apical turns. Young’s modulus determined at the BM pectinate zone was 76.8 ± 72, 23.9 ± 30.6, and 9.4 ± 6.2 kPa for the basal, middle, and apical turns, respectively. The reported stiffness values of the CBA/CaJ mouse TM and BM provide basic data for the physical properties of its organ of Corti.     

Human Yaw Rotation Aftereffects with Brief Duration Rotations Are Inconsistent with Velocity Storage

In many sensory systems, perception of stimuli is influenced by previous stimulus exposure such that subsequent stimuli may be perceived as more neutral. This phenomenon is known as an aftereffect and has been studied for vision, audition, and some vestibular stimuli including roll and translation. Previous data on yaw rotation perception has focused on low-frequency stimuli on the order of a minute which may not be directly applicable to frequencies during ambulation. The aim of the current study is to look at the influence of yaw rotation on subsequent perception near 1 Hz, the predominant frequency of yaw rotation during human ambulation. Humans were rotated with 12 ° whole body adapting stimulus over 1 or 1.5 s. After an interstimulus interval (ISI) of 0.5, 1.0, 1.5, or 3 s, a test stimulus the same duration as the adapting stimulus was presented, and subjects pushed a button to identify the direction of the test stimulus as right or left. The direction and magnitude of the test stimulus was adjusted based on prior responses to find the stimulus at which no rotation was perceived. Experiments were conducted both in darkness and with a visual fixation point. The presence of a fixation point did not influence the aftereffect which was largest at 0.5 s with an average size of 0.78 ± 0.18 °/s (mean ± SE). The aftereffect diminished with a time constant of ~1 s. Thresholds were elevated after the adapting stimulus and also decreased with a time constant of ~1 s. These findings demonstrate that short adapting stimuli can induce significant aftereffects in yaw rotation perception and that these aftereffects are independent from the previously described velocity storage.     

Three-dimensional morphology of the vestibular cleft and its potential application.

HYPOTHESIS: To delineate quantitatively the spatial relationships of the utricle, saccule, and stapedial footplate, to locate the hole on the footplate, and to analyze the insertion depth into the vestibule and the direction of the piston during stapedotomy. BACKGROUND: The quantitative three-dimensional (3D) configuration of the utricle, saccule, and stapedial footplate is undetermined, and the stapedotomy procedures should be improved. METHODS: Four temporal bones were extracted from the fresh cadavers and were undecalcified polymer-embedded. The specimens were sectioned into serial 50-mum-thickness slices. After image processing and 3D reconstruction, a cartesian coordinate system was established to display the spatial relationships of the utricle, saccule, and stapedial footplate in the 3D Studio Max scene. The configuration of the utricle, the saccule, and the "vestibular cleft" was delineated quantitatively with the contour map method. With this contour map, any distance between one point at the surface of the footplate and another point at the surface of the utricle or saccule and its orientation can be measured. RESULTS: There was a V-shaped cleft between the utricle and the saccule named vestibular cleft. The angle of the cleft was 50.30 degrees +/- 19.90 degrees . The apex of the cleft always directed anterosuperiorly, whereas beneath the posteroinferior part of the footplate was an open and deep "seabed." The vertical distances between points on the tympanic surface of the footplate and points on the surface of the utricle or saccule were measured. The vertical distance from the center point of footplate to the vestibular end organs was 2.20 +/- 0.548 mm, the maximum distance being 3.0 mm, whereas the minimum distance was 1.6 mm. CONCLUSION: The posteroinferior area near the central point of the footplate is the optimal position for the fenestra through which the piston can be inserted relatively safely into a depth of 0.8 to 1.0 mm in the vestibule. If the deep end of the piston is inclined inferiorly and posteriorly by 8 to 10 degrees, respectively, the piston will be farther from the vestibular end organs. These manipulations may enhance surgical safety and efficiency in stapedotomy.     

Hyperpolarization-Activated Current (I h) in Vestibular Calyx Terminals: Characterization and Role in Shaping Postsynaptic Events

Calyx afferent terminals engulf the basolateral region of type I vestibular hair cells, and synaptic transmission across the vestibular type I hair cell/calyx is not well understood. Calyces express several ionic conductances, which may shape postsynaptic potentials. These include previously described tetrodotoxin-sensitive inward Na⁺ currents, voltage-dependent outward K⁺ currents and a K(Ca) current. Here, we characterize an inwardly rectifying conductance in gerbil semicircular canal calyx terminals (postnatal days 3–45), sensitive to voltage and to cyclic nucleotides. Using whole-cell patch clamp, we recorded from isolated calyx terminals still attached to their type I hair cells. A slowly activating, noninactivating current (I_h) was seen with hyperpolarizing voltage steps negative to the resting potential. External Cs⁺ (1–5 mM) and ZD7288 (100 μM) blocked the inward current by 97 and 83 %, respectively, confirming that I_h was carried by hyperpolarization-activated, cyclic nucleotide gated channels. Mean half-activation voltage of I_h was −123 mV, which shifted to −114 mV in the presence of cAMP. Activation of I_h was well described with a third order exponential fit to the current (mean time constant of activation, τ, was 190 ms at −139 mV). Activation speeded up significantly (τ = 136 and 127 ms, respectively) when intracellular cAMP and cGMP were present, suggesting that in vivo I_h could be subject to efferent modulation via cyclic nucleotide-dependent mechanisms. In current clamp, hyperpolarizing current steps produced a time-dependent depolarizing sag followed by either a rebound afterdepolarization or an action potential. Spontaneous excitatory postsynaptic potentials (EPSPs) became larger and wider when I_h was blocked with ZD7288. In a three-dimensional mathematical model of the calyx terminal based on Hodgkin–Huxley type ionic conductances, removal of I_h similarly increased the EPSP, whereas cAMP slightly decreased simulated EPSP size and width.     

小鼠前庭器官的形态发生

目的了解小鼠前庭器官发育的形态学特征及演变规律.方法利用光镜、扫描电镜、透射电镜观察C57BL/6小鼠从胚胎第8天到刚出生期间前庭器官发育过程中的形态变化.结果 C57BL/6小鼠的前庭器官在胚胎第10.5天开始发育,胚胎第11.5天形成上、后半规管始基,到胚胎第12天水平半规管始基才逐渐形成,椭圆囊已出现许多原始的感觉纤毛,而到胚胎第13天,球囊才开始发育;到胚胎第15天,椭圆囊、球囊、壶腹嵴初具成熟形态,毛细胞和支持细胞也初具雏形,到出生时,前庭器官已基本发育成熟.结论 C57BL/6小鼠前庭感觉细胞在胚胎第12天开始分化,感觉上皮的形态从胚胎第12天至第18天变化最明显.椭圆囊、壶腹嵴的发生较早,随后才形成球囊,到出生时前庭感觉器官已基本发育成熟.     

Directional Plasticity Rapidly Improves 3D Vestibulo-Ocular Reflex Alignment in Monkeys Using a Multichannel Vestibular Prosthesis

Bilateral loss of vestibular sensation can be disabling. We have shown that a multichannel vestibular prosthesis (MVP) can partly restore vestibular sensation as evidenced by improvements in the 3-dimensional angular vestibulo-ocular reflex (3D VOR). However, a key challenge is to minimize misalignment between the axes of eye and head rotation, which is apparently caused by current spread beyond each electrode’s targeted nerve branch. We recently reported that rodents wearing a MVP markedly improve 3D VOR alignment during the first week after MVP activation, probably through the same central nervous system adaptive mechanisms that mediate cross-axis adaptation over time in normal individuals wearing prisms that cause visual scene movement about an axis different than the axis of head rotation. We hypothesized that rhesus monkeys would exhibit similar improvements with continuous prosthetic stimulation over time. We created bilateral vestibular deficiency in four rhesus monkeys via intratympanic injection of gentamicin. A MVP was mounted to the cranium, and eye movements in response to whole-body passive rotation in darkness were measured repeatedly over 1 week of continuous head motion-modulated prosthetic electrical stimulation. 3D VOR responses to whole-body rotations about each semicircular canal axis were measured on days 1, 3, and 7 of chronic stimulation. Horizontal VOR gain during 1 Hz, 50 °/s peak whole-body rotations before the prosthesis was turned on was <0.1, which is profoundly below normal (0.94 ± 0.12). On stimulation day 1, VOR gain was 0.4–0.8, but the axis of observed eye movements aligned poorly with head rotation (misalignment range ∼30–40 °). Substantial improvement of axis misalignment was observed after 7 days of continuous motion-modulated prosthetic stimulation under normal diurnal lighting. Similar improvements were noted for all animals, all three axes of rotation tested, for all sinusoidal frequencies tested (0.05–5 Hz), and for high-acceleration transient rotations. VOR asymmetry changes did not reach statistical significance, although they did trend toward slight improvement over time. Prior studies had already shown that directional plasticity reduces misalignment when a subject with normal labyrinths views abnormal visual scene movement. Our results show that the converse is also true: individuals receiving misoriented vestibular sensation under normal viewing conditions rapidly adapt to restore a well-aligned 3D VOR. Considering the similarity of VOR physiology across primate species, similar effects are likely to occur in humans using a MVP to treat bilateral vestibular deficiency.     

Current Steering with Partial Tripolar Stimulation Mode in Cochlear Implants

The large spread of excitation is a major cause of poor spectral resolution for cochlear implant (CI) users. Partial tripolar (pTP) mode has been proposed to reduce current spread by returning an equally distributed fraction (0.5 × σ) of current to two flanking electrodes and the rest to an extra-cochlear ground. This study tested the efficacy of incorporating current steering into pTP mode to add spectral channels. Different proportions of current [α × σ and (1 − α) × σ] were returned to the basal and apical flanking electrodes respectively to shape the electric field. Loudness and pitch perception with α from 0 to 1 in steps of 0.1 was simulated with a computational model of CI stimulation and tested on the apical, middle, and basal electrodes of six CI subjects. The highest σ allowing for full loudness growth within the implant compliance limit was chosen for each main electrode. Pitch ranking was measured between pairs of loudness-balanced steered pTP stimuli with an α interval of 0.1 at the most comfortable level. Results demonstrated that steered pTP stimuli with α around 0.5 required more current to achieve equal loudness than those with α around 0 or 1, maybe due to more focused excitation patterns. Subjects usually perceived decreasing pitches as α increased from 0 to 1, somewhat consistent with the apical shift of the center of gravity of excitation pattern in the model. Pitch discrimination was not better with α around 0.5 than with α around 0 or 1, except for some subjects and electrodes. For three subjects with better pitch discrimination, about half of the pitch ranges of two adjacent main electrodes overlapped with each other in steered pTP mode. These results suggest that current steering with focused pTP mode may improve spectral resolution and pitch perception with CIs.     

Gentamicin is Primarily Localized in Vestibular Type I Hair Cells after Intratympanic Administration

Intratympanic (IT) gentamicin injections are effective in the control of episodic vertigo due to Ménière’s disease. Histological studies in animals have found that the loss of type I vestibular hair cells far exceeds that of type II cells after IT gentamicin treatment. The objective of this study was to determine whether this selective toxicity for type I hair cells might be due to selective concentration of the drug by these cells. Gentamicin was localized within the vestibular epithelium by both direct and indirect methods. Gentamicin conjugated to Texas Red® was used as a direct tracer, and anti-gentamicin antibody provided an indirect means of localization. Conjugated or unconjugated gentamicin was injected into the left tympanic space of chinchillas. The animals were killed and fixed 1 or 3 weeks post-treatment. Confocal fluorescence microscopy was used to determine the localization of gentamicin in semicircular canal cristae. Results from the animals killed within 1 week of administration showed that numerous type I hair cells still remained throughout the epithelium. The mean intensity in grayscale units (0–255) of anti-gentamicin labeling for type I hair cells was 28.14 (95% CI 24.60–31.69), for type II hair cells was 17.09 (14.99–19.20), and for support cells was 5.35 (5.34–5.46; p < 0.001, ANOVA). Anti-gentamicin antibody labeling appeared in the majority of type I hair cells throughout their cytoplasm, but with greater intensity at the apex (p < 0.001). Intensity of fluorescence with Texas-Red conjugated gentamicin was 25.38 (22.83–27.94) in type I hair cells, 15.60 (14.73–16.48) in type II cells, and 12.62 (12.06–13.17) in support cells (p < 0.001, ANOVA). These results suggest that type I hair cells are more susceptible to gentamicin because they more avidly take up or retain the drug in the early period after administration.     

Compound gravity receptor polarization vectors evidenced by linear vestibular evoked potentials.

The utricle and saccule are gravity receptor organs of the vestibular system. These receptors rely on a high-density otoconial membrane to detect linear acceleration and the position of the cranium relative to Earth's gravitational vector. The linear vestibular evoked potential (VsEP) has been shown to be an effective non-invasive functional test specifically for otoconial gravity receptors (Jones et al., 1999). Moreover, there is some evidence that the VsEP can be used to independently test utricular and saccular function (Taylor et al., 1997; Jones et al., 1998). Here we characterize compound macular polarization vectors for the utricle and saccule in hatchling chickens. Pulsed linear acceleration stimuli were presented in two axes, the dorsoventral (DV, +/- Z axis) to isolate the saccule, and the interaural (IA, +/- Y axis) to isolate the utricle. Traditional signal averaging was used to resolve responses recorded from the surface of the skull. Latency and amplitude of eighth nerve components of the linear VsEP were measured. Gravity receptor responses exhibited clear preferences for one stimulus direction in each axis. With respect to each utricular macula, lateral translation in the IA axis produced maximum ipsilateral response amplitudes with substantially greater amplitude intensity (AI) slopes than medially directed movement. Downward caudal motions in the DV axis produced substantially larger response amplitudes and AI slopes. The results show that the macula lagena does not contribute to the VsEP compound polarization vectors of the sacculus and utricle. The findings suggest further that preferred compound vectors for the utricle depend on the pars externa (i.e. lateral hair cell field) whereas for the saccule they depend on pars interna (i.e. superior hair cell fields). These data provide evidence that maculae saccule and utricle can be selectively evaluated using the linear VsEP.     

Otolithenfunktionsstörungen

In the clinical routine, the diagnostic of the lateral gait is often comparable with a complete peripheral vestibular function examination. Diseases of the otolithic organs, with the saccule and utricle are not identified with conventional clinical examination methods. In more than 50% of patients with thermal hypostimulation, orientation tests show a simultaneous pathology of the utricle function. Participation of the saccule has been described for vestibular neuropathy, Menière's disease, bilateral vestibulopathy and acoustic neurinoma. Both otolithic organs are included in posttraumatic vertigo, a recognition, which will influence expert opinions in the future. Only by an exact diagnostic of diseases of the otolithic organs can individual disease courses be differential diagnostically separated from each other.     

Die kohlensäureanhydratase im innenohr des meerschweinchens und ihre hemmung

Zusammenfassung Im Innenohr des Meerschweinchens läßt sich die Kohlensäureanhydratase histochemisch in der Stria vascularis, in den Epithelien von Sacculus und Utriculus sowie in den Ampullen nachweisen. Der Einfluß von Acetazolamid and Dinatrium-EDTA auf das Ferment wind histochemisch verglichen.

---

A histochemical study of carbonic anhydrase and its inhibition of the inner ear of the guinea-pig

Summary The cells of the stria vascularis, the epithelial cells of saccule, utricle and ampullae have been examined and identified histochemically. These cells contain the carbonic anhydrase. The effects of acetalzolamid and disodium-EDTA to this enzyme are also compared histochemically.

     

Growth inhibitory response and ultrastructural modification of oral-associated candidal reference strains （ATCC） by Piper betle L. extract

Candida species have been associated with the emergence of strains resistant to selected antifungal agents. Plant products have been used traditionally as alternative medicine to ease mucosal fungal infections. This study aimed to investigate the effects of Piper betle extract on the growth profile and the ultrastructure of commonly isolated oral candidal cells. The major component of Po betle was identified using liquid chromatography-mass spectrophotometry （LC-MS/MS）. Seven ATCC control strains of Candida species were cultured in yeast peptone dextrose broth under four different growth environments： （i） in the absence of P. betle extract; and in the presence of P. beUeextract at respective concentrations of （ii） 1 mg.mL-1; （iii） 3 mg.mL-1; and （iv） 6 mg.mL- 1 The growth inhibitory responses of the candidal cells were determined based on changes in the specific growth rates （μ）. Scanning electron microscopy （SEM） was used to observe any ultrastructural alterations in the candida colonies. LC-MS/MS was performed to validate the presence of bioactive compounds in the extract. Following treatment, it was observed that the p-values of the treated cells were significantly different than those of the untreated cells （P〈0.05）, indicating the fungistatic properties of the P. beUe extract. The candidal population was also reduced from an average of 13.44× 10^6 to 1.78×10^6 viable cell counts （CFU）.mL-1, SEM examination exhibited physical damage and considerable morphological alterations of the treated cells. The compound profile from LC-MS/MS indicated the presence of hydroxybenzoic acid, chavibetol and hydroxychavicol in P. betle extract. The effects of P. betle on candida cells could potentiate its antifungal activity.     

Endolymphatic hydrops evaluation on MRI: Practical considerations

Four-hour delayed three-dimensional fluid-attenuated inversion recovery (3D-FLAIR) sequence after intravenous gadolinium-based contrast agent administration is an optimal magnetic resonance imaging technique to evaluate endolymphatic hydrops in patients with known or suspected Ménière's disease. Nonenhanced endolymphatic space surrounded by enhanced perilymphatic space is evaluated in the cochlea and vestibule separately. In cochlear hydrops, the scala media is enlarged, potentially obliterating the scala vestibuli. In vestibular hydrops, the size of the saccule becomes equal to or larger than that of the utricle; as hydrops progresses, the saccule and utricle become larger and confluent until complete obliteration of the vestibule's perilymphatic space.In patients with a unilateral clinical presentation of Ménière's disease, it is possible to depict the asymmetries of perilymph enhancement, which may be increased on the affected side and reflect a permeability alteration of the blood-perilymph barrier. In addition, endolymphatic hydrops can be observed in the asymptomatic ear of these patients with a unilateral clinical presentation, showing that Ménière's disease tends to undergo bilateral evolution over time.