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myogenic tone

Josef Donnerer, Ingrid Liebmann
Allyl isothiocyanate (AITC, mustard oil, 50-200 µmol/l), depending on specific dosages, inhibited the cholinergic twitch response in the longitudinal muscle-myenteric plexus (LMMP) strip of the guinea-pig ileum. AITC also induced short-lasting contractile responses, and decreases of the basal tone of the LMMP strip at low concentrations and increases at high concentrations. Hexamethonium, a blocker of nicotinic ganglionic transmission, was able to prevent the AITC-evoked inhibitory effect, an effect that was also observed with the opioid antagonist naloxone...
October 19, 2016: Pharmacology
Neil S Patel, Jacob B Hunter, Brendan P O'Connell, Natalie M Bertrand, George B Wanna, Matthew L Carlson
OBJECTIVE: Patients with incidental or minimally symptomatic superior semicircular canal dehiscence (SSCD) are usually observed, without surgical repair. However, it remains unknown whether a labyrinthine fistula of the superior semicircular canal is associated with progressive conductive or sensorineural hearing loss over time. STUDY DESIGN: Retrospective review at two tertiary care academic referral centers. METHODS: Adults analyzed were diagnosed with SSCD by high-resolution temporal bone computed tomography and vestibular evoked myogenic potential testing and observed with a minimum of two sequential audiograms...
October 14, 2016: Laryngoscope
Hasan Demirhan, Muhammet Yıldız, Özgür Yiğit
OBJECTIVE: The objective of this study was to explore the usefulness of 1000-Hz tone burst (TB) stimuli for detecting cervical vestibular-evoked myogenic potential (cVEMP) abnormalities in patients with a cochlear implant (CI). MATERIALS AND METHODS: Thirty asymptomatic patients who received unilateral CI because of severe bilateral sensorineural hearing loss were assessed for cVEMP produced by TB stimuli at two frequencies (500 and 1000 Hz) in the airway. VEMPs were recorded when the devices were switched to the on (CI-on) and off (CI-off) positions...
August 2016: Journal of International Advanced Otology
Jennifer J DuPont, Amy McCurley, Ana P Davel, Joseph McCarthy, Shawn B Bender, Kwangseok Hong, Yan Yang, Jeung-Ki Yoo, Mark Aronovitz, Wendy E Baur, Demetra D Christou, Michael A Hill, Iris Z Jaffe
Hypertension is nearly universal yet poorly controlled in the elderly despite proven benefits of intensive treatment. Mice lacking mineralocorticoid receptors in smooth muscle cells (SMC-MR-KO) are protected from rising blood pressure (BP) with aging, despite normal renal function. Vasoconstriction is attenuated in aged SMC-MR-KO mice, thus they were used to explore vascular mechanisms that may contribute to hypertension with aging. MicroRNA (miR) profiling identified miR-155 as the most down-regulated miR with vascular aging in MR-intact but not SMC-MR-KO mice...
September 8, 2016: JCI Insight
Hong Liu, Ting Zhang, Qianru Wu, Yibo Zhang, Chunfu Dai
CONCLUSIONS: One-shot, low-dose intra-tympanic gentamicin (ITG) treatment was effective and safe for Ménière's disease (MD) patients. Head thrust test (HTT) and vestibular evoked myogenic potentials (VEMPs) test could be used as endpoint indicators for vertigo control in MD patients. OBJECTIVES: The present study is to explore end-point indicators of ITG injection in MD. METHODS: Patients with MD were reviewed from June 2012 to March 2014...
September 9, 2016: Acta Oto-laryngologica
Lori S Kang, Shyama Masilamani, Matthew A Boegehold
Previous studies have documented that rapid juvenile growth is accompanied by functional changes in the arteriolar endothelium, but much less is known about functional changes in arteriolar smooth muscle over this period. In this study, we investigated the possible contribution of epithelial sodium channels (ENaC) to the myogenic behavior of arterioles at two stages of juvenile growth. The effects of the ENaC inhibitor benzamil on different levels of myogenic tone were studied in isolated gracilis muscle arterioles from rats aged 21-28 days ("weanlings") and 42-49 days ("juveniles")...
August 25, 2016: Clinical and Experimental Pharmacology & Physiology
Maha Coucha, Mohammed Abdelsaid, Weiguo Li, Maribeth H Johnson, Laszlo Orfi, Azza B El-Remessy, Susan C Fagan, Adviye Ergul
UNLABELLED: Ischemia/reperfusion and the resulting oxidative/nitrative stress impair cerebral myogenic tone via actin depolymerization. While it is known that NADPH oxidase (Nox) family is a major source of vascular oxidative stress; the extent and mechanisms by which Nox activation contributes to actin depolymerization, and equally important, the relative role of Nox isoforms in this response is not clear. AIM: To determine the role of Nox4 in hypoxia-mediated actin depolymerization and myogenic-tone impairment in cerebral vascular smooth muscle...
October 15, 2016: Life Sciences
Soo-Kyoung Choi, Mihwa Lim, Seon-Hee Byeon, Young-Ho Lee
Endoplasmic reticulum (ER) stress has been shown to play a critical role in the pathogenesis of cardiovascular complications. However, the role and mechanisms of ER stress in hypertension remain unclear. Thus, we hypothesized that enhanced ER stress contributes to the maintenance of hypertension in spontaneously hypertensive rats (SHRs). Sixteen-week old male SHRs and Wistar Kyoto Rats (WKYs) were used in this study. The SHRs were treated with ER stress inhibitor (Tauroursodeoxycholic acid; TUDCA, 100 mg/kg/day) for two weeks...
2016: Scientific Reports
Toshihisa Murofushi, Sakurako Komiyama, Ryota Suizu
OBJECTIVE: To determine the optimal method for detecting saccular endolymphatic hydrops (EH) in patients with Ménière's disease (MD) using a glycerol cervical vestibular evoked myogenic potential (cVEMP) test in combination with a tuning property test. STUDY DESIGN: Prospective patients series. SETTING: Tertiary referral center. PATIENTS: Twenty-three subjects (age: 36-77 years) were enrolled in this study. Seventeen subjects were diagnosed with definite MD...
September 2016: Otology & Neurotology
A Gallo, D Rosenbaum, A Mattina, E Koch, N Kachenoura, M Paques, X Girerd
OBJECTIVE: To evaluate the effects of blood pressure (BP) drop on retinal arteriole remodeling in hypertensive patients in a short-term vs long-term follow-up. DESIGN AND METHOD: 57 hypertensive subjects without diabetes were consecutively enrolled and evaluated at baseline, 6 weeks (short-term) and 40 weeks (long-term). Among them, 28 had stable BP and 29 had BP drop after prescription of antihypertensive therapy after baseline visit. Adaptive Optics Camera using RTX1® (ImagineEye, Orsay, France) was used to measure Wall Thickness (WT), Internal Diameter (ID), Wall Cross Sectional Area (WCSA) and Wall-to-Lumen Ratio (WLR)...
September 2016: Journal of Hypertension
Robert Gürkov, Guillaume Speierer, Luis Wittwer, Roger Kalla
OBJECTIVE: Recently, it could be demonstrated that an increased intracranial pressure causes a modulation of the air conducted sound evoked ocular vestibular evoked myogenic potential (oVEMP). The mechanism for this modulation is not resolved and may depend on a change of either receptor excitability or sound energy transmission. DESIGN: oVEMPs were elicited in 18 healthy subjects with a minishaker delivering 500 and 1000 Hz tone bursts, in supine and tilted positions...
July 27, 2016: Ear and Hearing
Ziad Mallat, Alain Tedgui, Daniel Henrion
The pathophysiology of aortic dissection is poorly understood, and its risk is resistant to medical treatment. Most studies have focused on a proposed pathogenic role of transforming growth factor-β in Marfan disease and related thoracic aortic aneurysms and aortic dissections. However, clinical testing of this concept using angiotensin II type 1 receptor antagonists to block transforming growth factor-β signaling fell short of promise. Genetic mutations that predispose to thoracic aortic aneurysms and aortic dissections affect components of the extracellular matrix and proteins involved in cellular force generation...
September 2016: Arteriosclerosis, Thrombosis, and Vascular Biology
Daogong Zhang, Zhaomin Fan, Yuechen Han, Yafeng Lv, Yawei Li, Haibo Wang
CONCLUSIONS: TSCP, which can reduce vertiginous symptoms in patients with intractable MD, represents an effective therapy for this disorder. OBJECTIVE: To explore the long-term efficacy of triple semicircular canal plugging (TSCP) in the treatment of intractable Meniere's disease (MD). METHODS: Seventy-nine patients diagnosed with unilateral MD referred to a vertigo clinic of the hospital between December 2010 and December 2013 were included in this study for retrospective analysis...
July 19, 2016: Acta Oto-laryngologica
T Michael De Silva, Dale A Kinzenbaw, Mary L Modrick, Lindsey D Reinhardt, Frank M Faraci
Rho kinase (ROCK) has been implicated in physiological and pathophysiological processes, including regulation of vascular function. ROCK signaling is thought to be a critical contributor to cardiovascular disease, including hypertension and effects of angiotensin II (Ang II). Two isoforms of ROCK (1 and 2) have been identified and are expressed in vascular cells. In this study, we examined the importance of ROCK2 in relation to vessel function using several models and a novel inhibitor of ROCK2. First, incubation of carotid arteries with the direct RhoA activator CN-03 or Ang II impaired endothelium-dependent relaxation by ≈40% to 50% (P<0...
September 2016: Hypertension
Pauliana Lamounier, Thiago Silva Almeida de Souza, Debora Aparecida Gobbo, Fayez Bahmad
INTRODUCTION: Ménière's disease (MD) is an inner ear disorder characterized by episodic vertigo, tinnitus, ear fullness, and fluctuating hearing. Its diagnosis can be especially difficult in cases where vestibular symptoms are present in isolation (vestibular MD). The definitive diagnosis is made histologically and can only be performed post-mortem, after analysis of the temporal bone. Endolymphatic hydrops is a histopathological finding of the disease and occurs more often in the cochlea and saccule, followed by the utricle and semicircular canals...
June 2, 2016: Brazilian Journal of Otorhinolaryngology
Jincheng Chen, Degui Gong, Shuhe Cai, Ziming Wu, Xingjian Lin, Xiaoyan Ma, Liqun Yu
OBJECTIVE: To analyze the characteristics of vestibular migraine (VM), in order to understand the auditory and vestibular function. METHOD: One hundred cases of confirmed or suspected VM patients were observed. Routine examination including pure tone test, vestibular dual temperature test and vestibular evoked myogenic potential(VEMP) and video head impulse test(v-HIT) Were conducted. RESULT: The incidence of male and female was about 1.00 : 2...
March 2016: Journal of Clinical Otorhinolaryngology, Head, and Neck Surgery
Michael Mederos Y Schnitzler, Ursula Storch, Thomas Gudermann
Myogenic vasoconstriction (Bayliss effect) is mediated by vascular smooth muscle cells (VSMCs) of small resistance arteries sensing mechanical forces. During the last three decades several proteins have been proposed as VSMC mechanosensors. Our previous studies highlighted agonist-independent mechanical activation of Gq/11 -protein coupled receptors (Gq/11 PCRs) in VSMCs of resistance arteries. In particular, angiotensin II AT1 receptors (AT1 Rs) emerged as mechanosensors mediating myogenic tone. Moreover, we found that the AT1B receptor isoform was more mechanosensitive than the AT1A receptor...
June 25, 2016: Microcirculation: the Official Journal of the Microcirculatory Society, Inc
Sertac Yetiser, Meltem Hale Gok, Yasar Kutukcu, Dilay Ince
The objective is to analyze the vestibular system by vestibular evoked myogenic potential (VEMP) in 30 female patients with migraine and balance problem in a controlled study. Thirty female patients with migraine and vestibular problems were enrolled in the study (2009-2012). Fifteen age-matched healthy subjects were selected as the controls. Air conduction cervical VEMP was used. Tone-burst sound stimuli of 95 dB nHL with rarefaction polarity, 5 Hz stimulus repetition rate, 1 ms rise/fall time and 2 ms plateau time were delivered at 500 Hz...
June 2016: Indian Journal of Otolaryngology and Head and Neck Surgery
Liang Chen, Hui Xu, Wu-Qing Wang, Qing-Quan Zhang, Qiao-Ying Lv, Xi-Cheng Song
BACKGROUND: Cervical and ocular vestibular evoked myogenic potentials (c/oVEMPs) reflect otolith function. Up-to-date, there are no published reports on the systemic evaluation of otolith function in Ménière's Disease (MD) nor are there any reports on the differences in VEMPs between patients with early and late stage MD. The aim of this study was to evaluate the difference in c/oVEMPs between patients with MD and normal controls, as well as between patients with early and late stage MD...
2016: Journal of Otolaryngology—Head & Neck Surgery
Harry R F Powell, Sherif S Khalil, Shakeel R Saeed
OBJECTIVE: To present the management strategy and outcomes for our series of superior semicircular canal dehiscence syndrome (SSCDS) patients. STUDY DESIGN: Retrospective cross-sectional study. SETTING: Tertiary referral center. PATIENTS: Thirty-seven consecutive patients referred from June 2011 to January 2015. Diagnosis of SSCDS based on presence of classical symptoms, computerized tomography, and concordant reduction in cervical vestibular evoked myogenic potentials...
August 2016: Otology & Neurotology
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