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https://www.readbyqxmd.com/read/28641325/superior-canal-dehiscence-syndrome-associated-with-scuba-diving
#1
Naoharu Kitajima, Akemi Sugita-Kitajima, Seiji Kitajima
A 28-year-old female diver presented with dizziness and difficulty clearing her left ear whilst scuba diving. Her pure-tone audiometry and tympanometry were normal. Testing of Eustachian tube function revealed tubal stenosis. Video-oculography revealed a predominantly torsional nystagmus while the patient was in the lordotic position. Fistula signs were positive. High-resolution computed tomography (HRCT) of the temporal bone revealed a diagnosis of bilateral superior semicircular canal dehiscence (SCDS). Cervical vestibular-evoked myogenic potential (cVEMP) testing showed that the amplitude of the cVEMP measured from her left ear was larger than that from the right...
June 2017: Diving and Hyperbaric Medicine: the Journal of the South Pacific Underwater Medicine Society
https://www.readbyqxmd.com/read/28603637/t-type-voltage-gated-ca-2-channels-do-not-contribute-to-the-negative-feedback-regulation-of-myogenic-tone-in-murine-superior-epigastric-arteries
#2
Brendan Mullan, Jessica Pettis, William F Jackson
T-type voltage-gated Ca(2+) channels (CaV3.2 VGCC) have been hypothesized to control spontaneous transient outward currents (STOCs) through large-conductance Ca(2+)-activated K(+) channels (BKCa), and contribute to the negative-feedback regulation of myogenic tone. We tested this hypothesis in superior epigastric arteries (SEAs) isolated from male C57BL/6 mice. SEAs were isolated and enzymatically dissociated to obtain single smooth muscle cells (SMCs) for whole-cell recording of paxilline-sensitive (PAX, 1 μmol/L) STOCs at -30 mV, or cannulated and studied by pressure myography (80 cm H2O, 37°C)...
June 2017: Pharmacology Research & Perspectives
https://www.readbyqxmd.com/read/28533763/is-alteration-of-tuning-property-in-cervical-vestibular-evoked-myogenic-potential-specific-for-m%C3%A3-ni%C3%A3-re-s-disease
#3
Toshihisa Murofushi, Masahito Tsubota, Ryota Suizu, Eriko Yoshimura
OBJECTIVE: The aim of this study is to show sensitivity and specificity of cervical vestibular-evoked myogenic potential (cVEMP) tuning property test to Ménière's disease (MD) in comparison with healthy controls (HC) and patients with other vestibular diseases. SUBJECTS: Totally 92 subjects (50 women and 42 men, 20-77 years of age) were enrolled in this study. Subjects were composed of 38 definite unilateral MD patients, 11 unilateral benign paroxysmal positional vertigo patients, 14 vestibular migraine patients, 19 unilateral vestibular neuritis patients, and 10 HC...
2017: Frontiers in Neurology
https://www.readbyqxmd.com/read/28520834/effect-of-electrode-montage-and-head-position-on-air-conducted-ocular-vestibular-evoked-myogenic-potential
#4
Kathryn Makowiec, Devin L McCaslin, Gary P Jacobson, Kelsey Hatton, John Lee
Purpose: The purpose of this investigation was to identify the optimal recording parameters for evoking the ocular vestibular evoked myogenic potential (oVEMP) using air-conduction stimuli. Method: Subjects were 17 otologically and neurologically intact adults (age: M = 24.18 years, SD = 1.91 years). The oVEMP responses were elicited using a 500-Hz tone burst air-conduction stimulus presented at an intensity of 95 dB nHL. The setting was a balance function laboratory that was part of a large tertiary care otology clinic...
June 13, 2017: American Journal of Audiology
https://www.readbyqxmd.com/read/28484390/spatiotemporal-mapping-techniques-show-clozapine-impairs-neurogenic-and-myogenic-patterns-of-activity-in-the-colon-of-the-rabbit-in-a-dose-dependent-manner
#5
Susanna Every-Palmer, Roger G Lentle, Gordon Reynolds, Corrin Hulls, Paul Chambers, Helen Dunn, Pete M Ellis
Background: Clozapine, an antipsychotic used in treatment-resistant schizophrenia, has adverse gastrointestinal effects with significant associated morbidity and mortality. However, its effects on defined patterns of colonic contractile activity have not been assessed. Method: We used novel radial and longitudinal spatiotemporal mapping techniques, combined with and monitoring of ambient lumen pressure, in ex vivo preparations of triply and of singly haustrated portions of rabbit colon. We identified the contractile patterns of mass peristalses, fast phasic, and ripple contractions and directly qualified the effects of clozapine, at concentrations of 10 μmol/L, 20 μmol/L, and 30 μmol/L, and of norclozapine, the main metabolite of clozapine, on contractile patterns...
2017: Frontiers in Pharmacology
https://www.readbyqxmd.com/read/28475214/the-angiotensin-ii-receptor-type-1b-is-the-primary-sensor-of-intraluminal-pressure-in-cerebral-artery-smooth-muscle-cells
#6
Paulo W Pires, Eun-A Ko, Harry A T Pritchard, Michael Rudokas, Evan Yamasaki, Scott Earley
Myogenic vasoconstriction, which reflects the intrinsic ability of smooth muscle cells to contract in response to increases in intraluminal pressure, is critically important for the autoregulation of blood flow. In SMC from cerebral arteries, increasing intraluminal pressure engages a signalling cascade that stimulates cation influx through transient receptor potential (TRP) melastatin 4 (TRPM4) channels to cause membrane depolarization and vasoconstriction. Substantial evidence indicates that the angiotensin II receptor type 1 (AT1 R) is inherently mechanosensitive and initiates this signalling pathway...
May 5, 2017: Journal of Physiology
https://www.readbyqxmd.com/read/28472069/detection-of-trpv4-channel-current-like-activity-in-fawn-hooded-hypertensive-fhh-rat-cerebral-arterial-muscle-cells
#7
Debebe Gebremedhin, David X Zhang, Dorothee Weihrauch, Nnamdi N Uche, David R Harder
The transient receptor potential vallinoid type 4 (TRPV4) is a calcium entry channel known to modulate vascular function by mediating endothelium-dependent vasodilation. The present study investigated if isolated cerebral arterial myocytes of the Fawn Hooded hypertensive (FHH) rat, known to display exaggerated KCa channel current activity and impaired myogenic tone, express TRPV4 channels at the transcript and protein level and exhibit TRPV4-like single-channel cationic current activity. Reverse transcription polymerase chain reaction (RT-PCR), Western blot, and immunostaining analysis detected the expression of mRNA transcript and translated protein of TRPV4 channel in FHH rat cerebral arterial myocytes...
2017: PloS One
https://www.readbyqxmd.com/read/28436247/effects-of-peripheral-vestibular-dysfunction-on-dynamic-postural-stability-measured-by-the-functional-reach-test-and-timed-up-and-go-test
#8
Toshiko Nishi, Teru Kamogashira, Chisato Fujimoto, Makoto Kinoshita, Naoya Egami, Keiko Sugasawa, Tatsuya Yamasoba, Shinichi Iwasaki
OBJECTIVE: To investigate the influence of vestibular function on dynamic postural stability assessed by the functional reach test (FRT) and the timed up and go test (TUG). STUDY DESIGN: Retrospective study. SETTING: Tertiary referral center. SUBJECTS AND METHODS: The FRT and TUG were performed in 399 patients with dizziness. The effects of peripheral vestibular dysfunction assessed by the caloric test and cervical vestibular evoked myogenic potentials (cVEMPs) to air-conducted sound (500 Hz, tone burst) on the results of FRT and TUG were analyzed...
June 2017: Annals of Otology, Rhinology, and Laryngology
https://www.readbyqxmd.com/read/28435971/-mechanisms-underlying-rat-coronary-arterial-vasoconstriction-induced-by-blockade-of-inward-rectifier-potassium-channels-with-bacl2
#9
Fang-Wen Fan, Ze-Fang He, Meng Shi, Rong Yang, Xiao-Min Hou, Yu Liu, Ming-Sheng Zhang
In order to explore the mechanisms underlying the vasoconstriction induced by blockade of inward rectifier K(+) channels (Kir) with BaCl2, myogenic tone of isolated rat coronary artery (RCA) was recorded with wire myograph. The dependence of BaCl2- induced contraction on intracellular Ca(2+) ([Ca(2+)]i) release and extracellular Ca(2+) ([Ca(2+)]o) influx was studied by Ca(2+) deprivation and restoration. The mechanisms underlying BaCl2-induced RCA contraction were investigated with specific inhibitors. BaCl2 (0...
April 25, 2017: Sheng Li Xue Bao: [Acta Physiologica Sinica]
https://www.readbyqxmd.com/read/28432059/increased-amplitude-of-inward-rectifier-k-currents-with-advanced-age-in-smooth-muscle-cells-of-murine-superior-epigastric-arteries
#10
Sebastien Hayoz, Jessica Pettis, Vanessa Bradley, Steven S Segal, William F Jackson
Inward rectifier K(+) channels (KIR) may contribute to skeletal muscle blood flow regulation and adapt to advanced age. Using mouse abdominal wall superior epigastric arteries (SEAs) from either young (3-6 months) or old (24-26 months) male C57BL/6 mice, we investigated whether SEA smooth muscle cells (SMCs) express functional KIR, and how aging may affect KIR function. Freshly dissected SEAs were either enzymatically dissociated to isolate SMCs for electrophysiological recording (perforated patch) and mRNA expression, or used intact for pressure myography...
April 21, 2017: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/28419063/the-effect-of-elevated-intracranial-pressure-on-frequency-tuning-of-air-conducted-ocular-vestibular-myogenic-potentials-in-m%C3%A3-ni%C3%A3-re-s-disease-patients
#11
Rebecca Maxwell, Claudia Jerin, Robert Gürkov
OBJECTIVE: To investigate the effect of increased intracranial pressure on ocular vestibular-evoked myogenic potential (oVEMP) amplitudes and frequency tuning in patients with Ménière's disease (MD) to elucidate whether oVEMPS recorded under such conditions could provide a simple and accurate diagnostic test for MD. SETTING: Tertiary referral center for otology and neurotology. PATIENTS: Ten patients with certain unilateral MD (mean age = 48...
July 2017: Otology & Neurotology
https://www.readbyqxmd.com/read/28396535/pregnancy-reprograms-large-conductance-ca-2-activated-k-channel-in-uterine-arteries-roles-of-ten-eleven-translocation-methylcytosine-dioxygenase-1-mediated-active-demethylation
#12
Xiang-Qun Hu, Chiranjib Dasgupta, Man Chen, Daliao Xiao, Xiaohui Huang, Limin Han, Shumei Yang, Zhice Xu, Lubo Zhang
The large-conductance Ca(2+)-activated K(+) (BKCa) channel is of critical importance in pregnancy-mediated increase in uterine artery vasodilation and blood flow. The present study tested the hypothesis that active DNA demethylation plays a key role in pregnancy-induced reprogramming and upregulation of BKCa channel β1 subunit (BKβ1) in uterine arteries. Uterine arteries were isolated from nonpregnant and near-term pregnant sheep. Pregnancy significantly increased the expression of ten-eleven translocation methylcytosine dioxygenase 1 (TET1) in uterine arteries...
June 2017: Hypertension
https://www.readbyqxmd.com/read/28378814/constitutive-smooth-muscle-tumour-necrosis-factor-regulates-microvascular-myogenic-responsiveness-and-systemic-blood-pressure
#13
Jeffrey T Kroetsch, Andrew S Levy, Hangjun Zhang, Roozbeh Aschar-Sobbi, Darcy Lidington, Stefan Offermanns, Sergei A Nedospasov, Peter H Backx, Scott P Heximer, Steffen-Sebastian Bolz
Tumour necrosis factor (TNF) is a ubiquitously expressed cytokine with functions beyond the immune system. In several diseases, the induction of TNF expression in resistance artery smooth muscle cells enhances microvascular myogenic vasoconstriction and perturbs blood flow. This pathological role prompted our hypothesis that constitutively expressed TNF regulates myogenic signalling and systemic haemodynamics under non-pathological settings. Here we show that acutely deleting the TNF gene in smooth muscle cells or pharmacologically scavenging TNF with etanercept (ETN) reduces blood pressure and resistance artery myogenic responsiveness; the latter effect is conserved across five species, including humans...
April 5, 2017: Nature Communications
https://www.readbyqxmd.com/read/28370794/short-term-48-hours-intravenous-serelaxin-infusion-has-no-effect-on-myogenic-tone-or-vascular-remodeling-in-rat-mesenteric-arteries
#14
Maria Jelinic, Chen Huei Leo, Sarah A Marshall, Sevvandi N Senadheera, Laura J Parry, Marianne Tare
BACKGROUND: Short-term intravenous serelaxin (recombinant human relaxin-2) infusion enhances endothelium-dependent relaxation in mesenteric arteries. This is initially underpinned by increased nitric oxide (NO) followed by a transition to prostacyclin. The effects of short-term intravenous serelaxin treatment on pressure-induced myogenic tone and vascular remodeling in these arteries are unknown. Therefore, we investigated the effects of serelaxin infusion on pressure-induced myogenic tone and passive mechanical wall properties in mesenteric arteries...
March 31, 2017: Microcirculation: the Official Journal of the Microcirculatory Society, Inc
https://www.readbyqxmd.com/read/28348547/altered-cervical-vestibular-evoked-myogenic-potential-in-children-with-attention-deficit-and-hyperactivity-disorder
#15
Valeria Isaac, Diego Olmedo, Francisco Aboitiz, Paul H Delano
OBJECTIVE: Emerging evidence suggests that children with attention deficit and hyperactivity disorder (ADHD) present more difficulties in standing and walking balance than typically developing children. Most of previous studies have assessed these functions using postural and sensory organization tests showing differences in balance performance between control and ADHD children. However, to date, it is unknown whether these balance alterations are accompanied with vestibular dysfunction...
2017: Frontiers in Neurology
https://www.readbyqxmd.com/read/28344549/functional-brain-activation-in-response-to-a-clinical-vestibular-test-correlates-with-balance
#16
Fatemeh Noohi, Catherine Kinnaird, Yiri DeDios, Igor S Kofman, Scott Wood, Jacob Bloomberg, Ajitkumar Mulavara, Rachael Seidler
The current study characterizes brain fMRI activation in response to two modes of vestibular stimulation: Skull tap and auditory tone burst. The auditory tone burst has been used in previous studies to elicit either a vestibulo-spinal reflex [saccular-mediated colic Vestibular Evoked Myogenic Potentials (cVEMP)], or an ocular muscle response [utricle-mediated ocular VEMP (oVEMP)]. Research suggests that the skull tap elicits both saccular and utricle-mediated VEMPs, while being faster and less irritating for subjects than the high decibel tones required to elicit VEMPs...
2017: Frontiers in Systems Neuroscience
https://www.readbyqxmd.com/read/28336540/effects-of-midline-sagittal-location-on-bone-conducted-cervical-and-ocular-vestibular-evoked-myogenic-potentials
#17
Sendhil Govender, James G Colebatch
We have investigated the effectiveness of two bone-conducted (BC) stimuli in producing vestibular evoked myogenic potentials (VEMPs) following stimulation along midsagittal skull sites. Twenty subjects (mean age 24 yr, range: 18-34 yr; 6 men; 14 women) were studied using a smoothed impulse and a 500-Hz tone burst applied to Nz, Fpz, AFz, Fz, FCz, and Cz with both compressive and rarefactive onset phases. Cervical (cVEMPs) and ocular VEMPs (oVEMPs) were recorded as well as linear acceleration in three axes. cVEMPs evoked by 500 Hz showed no change in response polarity to either stimulus location or phase...
June 1, 2017: Journal of Applied Physiology
https://www.readbyqxmd.com/read/28333380/smooth-muscle-ion-channels-and-regulation-of-vascular-tone-in-resistance-arteries-and-arterioles
#18
Nathan R Tykocki, Erika M Boerman, William F Jackson
Vascular tone of resistance arteries and arterioles determines peripheral vascular resistance, contributing to the regulation of blood pressure and blood flow to, and within the body's tissues and organs. Ion channels in the plasma membrane and endoplasmic reticulum of vascular smooth muscle cells (SMCs) in these blood vessels importantly contribute to the regulation of intracellular Ca2+ concentration, the primary determinant of SMC contractile activity and vascular tone. Ion channels provide the main source of activator Ca2+ that determines vascular tone, and strongly contribute to setting and regulating membrane potential, which, in turn, regulates the open-state-probability of voltage gated Ca2+ channels (VGCCs), the primary source of Ca2+ in resistance artery and arteriolar SMCs...
March 16, 2017: Comprehensive Physiology
https://www.readbyqxmd.com/read/28289399/auditory-and-vestibular-evoked-potentials-correlate-with-motor-and-non-motor-features-of-parkinson-s-disease
#19
Ali Soliman Shalash, Dalia Mohamed Hassan, Hanan Hani Elrassas, Mohamed Mosaad Salama, Edna Méndez-Hernández, José M Salas-Pacheco, Oscar Arias-Carrión
Degeneration of several brainstem nuclei has been long related to motor and non-motor symptoms (NMSs) of Parkinson's disease (PD). Nevertheless, due to technical issues, there are only a few studies that correlate that association. Brainstem auditory-evoked potential (BAEP) and vestibular-evoked myogenic potential (VEMP) responses represent a valuable tool for brainstem assessment. Here, we investigated the abnormalities of BAEPs, ocular VEMPs (oVEMPs), and cervical VEMPs (cVEMPs) in patients with PD and its correlation to the motor and NMSs...
2017: Frontiers in Neurology
https://www.readbyqxmd.com/read/28280468/rok-and-arteriolar-myogenic-tone-generation-molecular-evidence-in-health-and-disease
#20
REVIEW
Ahmed F El-Yazbi, Khaled S Abd-Elrahman
The myogenic response is an inherent property of resistance arteries that warrants a relatively constant blood flow in response to changes in perfusion pressure and protect delicate organs from vascular insufficiencies and excessive blood flow. This fundamental phenomenon has been extensively studied aiming to elucidate the underlying mechanisms triggering smooth muscle contraction in response to intraluminal pressure elevation, particularly, Rho-associated kinase (ROK)-mediated Ca(2+)-independent mechanisms...
2017: Frontiers in Pharmacology
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