scholarly journals Quantitative assessment of anti-gravity reflexes to evaluate vestibular dysfunction in rats

2019 ◽  
Author(s):  
Vanessa Martins-Lopes ◽  
Anna Bellmunt ◽  
Erin A. Greguske ◽  
Alberto F. Maroto ◽  
Pere Boadas-Vaello ◽  
...  
Keyword(s):  
Vestibular Function ◽  
Correlation Coefficients ◽  
Slow Motion ◽  
Vestibular Dysfunction ◽  
Cell Degeneration ◽  
Sensory Epithelia ◽  
Righting Reflex ◽  
Vestibular Sensory Epithelia ◽  
Further Development ◽  
Dose Dependent

AbstractThe tail-lift reflex and the air-righting reflex are anti-gravity reflexes in rats that depend on vestibular function. To obtain objective and quantitative measures of performance, we recorded these reflexes with slow motion video in two experiments. In the first experiment, vestibular dysfunction was elicited by acute exposure to 0 (control), 400, 600 or 1000 mg/kg of 3,3’-iminodipropionitrile (IDPN), which causes dose-dependent hair cell degeneration. In the second, rats were exposed to sub-chronic IDPN in the drinking water for 0 (control), 4 or 8 weeks; this causes reversible or irreversible loss of vestibular function depending on exposure time. In the tail-lift test, we obtained the minimum angle defined during the lift and descent maneuver by the nose, the back of the neck and the base of the tail. In the air-righting test, we obtained the time to right the head. We also obtained Vestibular Dysfunction Ratings (VDRs) using a previously validated behavioral test battery. Each measure, VDR, tail-lift angle and air-righting time, demonstrated dose-dependent loss of vestibular function after acute IDPN, and time-dependent loss of vestibular function after sub-chronic IDPN. All measures showed high correlations between each other, and maximal correlation coefficients were found between VDRs and tail-lift angles. In scanning electron microscopy evaluation of the vestibular sensory epithelia, the utricle and the saccule showed diverse pathological outcomes, suggesting that they have a different role in these reflexes. We conclude that these anti-gravity reflexes provide useful objective and quantitative measures of vestibular function in rats that are open to further development.

scholarly journals Differential role of type I and type II vestibular hair cells in two anti-gravity reflexes in the rat

2020 ◽  
Author(s):  
Alberto F. Maroto ◽  
Alejandro Barrallo-Gimeno ◽  
Jordi Llorens
Keyword(s):  
High Speed ◽  
Video Recording ◽  
Vestibular Function ◽  
Type I ◽  
Type Ii ◽  
Vestibular Hair Cells ◽  
Sensory Epithelia ◽  
Righting Reflex ◽  
Vestibular Sensory Epithelia

AbstractThe tail-lift reflex and the air-righting reflex in rats are anti-gravity reflexes that depend on vestibular function. We assessed reflex loss in relationship to the graded lesions caused in the vestibular sensory epithelia by varying doses of an ototoxic compound. Using high-speed video recording, we obtained nose-back of the neck-tail angles from the tail-lift reflex and time to right in the air-righting test. We then correlated these measures with type I (HCI), type II (HCII) and all hair cell (HC) counts in central and peripheral zones of the crista, utricle, and saccule. Correlations varied with the cell type, zone and end-organ considered, and those of tail-lift angles were strikingly greater with HCI counts that HCII counts. A similar HCI vs HCII difference was not recorded for air-righting times. We conclude that these two reflexes depend differently on HCI and HCII function and that the tail-lift angle measures HCI function.

On the Legacy of Genetically Altered Mouse Models to Explore Vestibular Function: Distribution of Vestibular Hair Cell Phenotypes in the Otoferlin-Null Mouse

2019 ◽  
Vol 128 (6_suppl) ◽  
pp. 125S-133S ◽  
Author(s):  
Terry J. Prins ◽  
Johnny J. Saldate ◽  
Gerald S. Berke ◽  
Larry F. Hoffman
Keyword(s):  
Hair Cell ◽  
Hair Cells ◽  
Vestibular Function ◽  
Null Mouse ◽  
Type I ◽  
Vestibular Hypofunction ◽  
Cellular Changes ◽  
Sensory Epithelia ◽  
Vestibular Sensory Epithelia ◽  
Cell Phenotypes

Objectives: Early in his career, David Lim recognized the scientific impact of genetically anomalous mice exhibiting otoconia agenesis as models of drastically compromised vestibular function. While these studies focused on the mutant pallid mouse, contemporary genetic tools have produced other models with engineered functional modifications. Lim and colleagues foresaw the need to analyze vestibular epithelia from pallid mice to verify the absence of downstream consequences that might be secondary to the altered load represented by otoconial agenesis. More generally, however, such comparisons also contribute to an understanding of the susceptibility of labyrinthine sensory epithelia to more widespread cellular changes associated with what may appear as isolated modifications. Methods: Our laboratory utilizes a model of vestibular hypofunction produced through genetic alteration, the otoferlin-null mouse, which has been shown to exhibit severely compromised stimulus-evoked neurotransmitter release in type I hair cells of the utricular striola. The present study, reminiscent of early investigations of Lim and colleagues that explored the utility of a genetically altered mouse to explore its utility as a model of vestibular hypofunction, endeavored to compare the expression of the hair cell marker oncomodulin in vestibular epithelia from wild-type and otoferlin-null mice. Results: We found that levels of oncomodulin expression were much greater in type I than type II hair cells, though were similar across the 3 genotypes examined (ie, including heterozygotes). Conclusion: These findings support the notion that modifications resulting in a specific component of vestibular hypofunction are not accompanied by widespread morphologic and cellular changes in the vestibular sensory epithelia.

The Scanning Electron Microscopic Observation of the Vestibular Sensory Epithelia

1969 ◽  
Vol 27 ◽  
pp. 40-41
Author(s):  
D.J. Lim ◽  
W.C. Lane
Keyword(s):  
Semicircular Canals ◽  
Electron Microscopic Observation ◽  
Gravitational Acceleration ◽  
Electron Microscopic ◽  
Sensory Epithelia ◽  
Scanning Electron Microscopic ◽  
Vestibular Sensory Epithelia ◽  
And Function ◽  
Sand Piles ◽  
Active Investigation

The morphology and function of the vestibular sensory organs has been extensively studied during the last decade with the advent of electron microscopy and electrophysiology. The opening of the space age also accelerated active investigation in this area, since this organ is responsible for the sensation of balance and of linear, angular and gravitational acceleration.The vestibular sense organs are formed by the saccule, utricle and three ampullae of the semicircular canals. The maculae (sacculi and utriculi) have otolithic membranes on the top of the sensory epithelia. The otolithic membrane is formed by a layer of thick gelatin and sand-piles of calcium carbonate crystals (Fig.l).

scholarly journals Assessment of cervical and ocular vestibular evoked myogenic potentials in migraine patients

2020 ◽  
Vol 36 (1) ◽  
Author(s):  
Doaa Elmoazen ◽  
Hesham Kozou ◽  
Jaidaa Mekky ◽  
Dalia Ghanem
Keyword(s):  
Vestibular Function ◽  
Vestibular Dysfunction ◽  
Peak Amplitude ◽  
Vestibular Evoked Myogenic Potentials ◽  
Healthy Controls ◽  
Latency Difference ◽  
Significant Difference ◽  
Cervical Vemp ◽  
Vestibular Symptoms ◽  
Function Assessment

Abstract Background Patients suffering from vestibular migraine (VM) are known to have various vestibular test abnormalities interictally and ictally. Recently, vestibular evoked myogenic potentials (VEMPs) have become accepted as a valid method for otolith function assessment. Many studies have identified various vestibular symptoms and laboratory abnormalities in migraineurs. Since migraineurs with no accompanying vestibular symptoms might exhibit subclinical vestibular dysfunction, we investigated vestibular function using ocular and cervical VEMPs in migraine patients. The aim was to study cervical VEMP and occular VEMP in migraineurs with and without vestibular symptoms interictally. Results Migraine and VM patients showed significantly longer P13 latency of cVEMP compared to controls. A statistically significant cVEMP interaural P13 latency difference was found in VM compared to healthy controls. Cervical VEMP N23 latency, peak-to-peak amplitude, interaural N23 latency, and amplitude asymmetric ratio did not show any significant difference in migraine and VM patients compared to healthy controls as well as no significant difference across the three groups regarding oVEMP parameters. Conclusions Abnormal interictal cVEMP results in migraineurs might indicate subclinical vestibulo-collic pathway dysfunction.

Behaviour of adult hamsters subjected to hypergravity

1999 ◽  
Vol 9 (1) ◽  
pp. 13-18
Author(s):  
H.N.P.M. Sondag ◽  
H.A.A. de Jong ◽  
W.J. Oosterveld
Keyword(s):  
Sensory Input ◽  
Normal Gravity ◽  
Vestibular Function ◽  
Calcium Content ◽  
Light Conditions ◽  
Altered Gravity ◽  
Normal Functioning ◽  
X Ray ◽  
Small Tube ◽  
Righting Reflex

We studied vestibular function in 20 adult hamsters (3 months old) subjected to either prolonged hypergravity (n=10) or normal gravity (n=10) for 2 months. Locomotion and swimming of the hypergravity hamsters under light conditions were normal. Equilibrium maintenance was severely disturbed; only 6 of 10 hypergravity hamsters managed to walk on the small tube after 2 months, whereas all 10 controls were able to walk on the tube. The air-righting reflex was severely disturbed; the hypergravity hamsters made 30% correct responses. Finally, 5 of 8 hypergravity hamsters had to be saved from drowning when swimming in total darkness. Histological examination of the utricular otoconial layers afterwards, using energy dispersive X-ray element (EDAX) analysis and scanning electron microscopy, did not reveal any differences in calcium content, shape and size distribution of the otoconia between hypergravity hamsters and controls. We suggest that adult hamsters adapt to hypergravity, leading to problems in normal functioning when tested in 1 G, especially in tasks in which sensory input of the vestibular system is important for spatial orientation. These disturbances were more severe in adult hamsters than in young ones, tested in previous experiments. Therefore, we assume that age is a factor for adaptation to altered gravity conditions.

scholarly journals 1360. Antimicrobial Activity of Cefepime in Combination with VNRX-5133 Against a Global Collection of Enterobacteriaceae Including Resistant Phenotypes

2018 ◽  
Vol 5 (suppl_1) ◽  
pp. S416-S417 ◽  
Author(s):  
Meredith Hackel ◽  
Dan Sahm
Keyword(s):  
Vitro Activity ◽  
In Vitro Activity ◽  
First Line ◽  
First Line Therapy ◽  
Carbapenem Resistant ◽  
Line Therapy ◽  
Resistant Strains ◽  
Further Development ◽  
Dose Dependent

Abstract Background VNRX-5133 is a novel cyclic boronate-based broad-spectrum β-lactamase inhibitor with potent and selective direct inhibitory activity against both serine- and metallo-β-lactamases (Ambler Classes A, B, C, and D). In this analysis, we evaluated the activity of cefepime (FEP) in combination with VNRX-5133 and comparators against 1,120 recent Enterobacteriaceae clinical isolates, including carbapenem-resistant strains. Methods MICs of FEP with VNRX-5133 fixed at 4 µg/mL (FEP/VNRX-5133) were determined following CLSI M07-A10 guidelines against 1,120 Enterobacteriaceae from community and hospital infections collected globally in 2012–2013. Resistant phenotypes were based on 2017 CLSI breakpoints. As FEP/VNRX-5133 breakpoints have not yet been established, the FEP 2 g q8h susceptible dose-dependent (SDD) breakpoint of ≤8 µg/mL was considered for comparative purposes. Results FEP/VNRX-5133 showed potent in vitro activity against drug-resistant subsets of Enterobacteriaceae, with MIC90 values ranging from 1 µg/mL against ceftazidime-, levofloxacin-, or piperacillin–tazobactam-nonsusceptible isolates, to 8 µg/mL against meropenem-nonsusceptible isolates. FEP/VNRX-5133 inhibited >93% of all resistant subsets at ≤8 µg/mL. Conclusion Cefepime in combination with VNRX-5133 demonstrated potent in vitro activity against Enterobacteriaceae, including cephalosporin-, fluoroquinolone- and carbapenem-resistant (CRE) isolates. Because this drug combination exhibited substantial potential for the treatment of infections caused by isolates often resistant to first-line therapy, further development is warranted. Disclosures M. Hackel, IHMA, Inc.: Employee, Salary. VenatoRx: Consultant, Consulting fee. D. Sahm, IHMA, Inc.: Employee, Salary. VenatoRx: Consultant, Consulting fee.

scholarly journals Vestibular prognosis in idiopathic sudden sensorineural hearing loss with vestibular dysfunction treated with oral or intratympanic glucocorticoids: a protocol for randomized controlled trial

2020 ◽  
Author(s):  
Huawei Li ◽  
Weiming Hao ◽  
Liping Zhao ◽  
Huiqian Yu
Keyword(s):  
Randomized Controlled Trial ◽  
Hearing Loss ◽  
Sensorineural Hearing Loss ◽  
Controlled Trial ◽  
Vestibular Function ◽  
Vestibular Dysfunction ◽  
Sudden Sensorineural Hearing Loss ◽  
Sensorineural Hearing ◽  
Hearing Outcome ◽  
Randomized Controlled

Abstract Background Idiopathic sudden sensorineural hearing loss (ISSNHL) is a rapid-onset sensorineural hearing impairment with unclear etiology and unsatisfying treatment effects. Vestibular dysfunction has been considered as a poor indicator in the clinical manifestations and prognosis of ISSNHL, which occurred in approximately 28%-57% cases. Glucocorticoids, administered through oral or intratympanic way, is currently a regular and standard treatment for ISSNHL based on hearing outcome. However, little investigations have been conducted on the recovery process and treatment effects of glucocorticoids on vestibular dysfunctions of ISSNHL. This study aims to compare the efficacy of oral or intratympanic glucocorticoids in ISSNHL with vestibular dysfunction in terms of the pattern and trajectory of possible process of vestibular function recovery.Methods/Design A randomized, outcome-assessor- and analyst-blinded, controlled, clinical trial (RCT) will be carried out. A group of seventy-two patients with ISSNHL complaining of vestibular dysfunction appearing as vertigo, dizziness or imbalance will be recruited and randomized into two arms of either oral or intratympanic glucocorticoids therapy with a 1:1 allocation ratio. The primary outcomes will be vestibular function outcomes assessed by sensory organization test, caloric test, video head impulse test, and vestibular evoked myogenic potentials; the secondary outcomes include self-reported vestibular dysfunction symptoms; dizziness-related handicap, visual analogue scale for vertigo and tinnitus; and pure tone audiometry. Assessment will be performed at baseline and at 1, 2, 4, and 8 weeks post-randomization. To our knowledge, this will be the first randomized controlled trial focusing on the prognosis of vestibular dysfunction in ISSNHL and the efficacy of glucocorticoids therapy for the vestibular dysfunction in this disease.Discussion This trial will be the first RCT study focusing on the progress and prognosis of vestibular dysfunction in ISSNHL. Efficacy of two commonly used therapies of glucocorticoids will be compared in both auditory and vestibular function fields, rather than in the hearing outcome alone. Trial registration ClinicalTrials.gov, NCT03974867. Registered on July 23, 2019.

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