The Experts below are selected from a list of 192 Experts worldwide ranked by ideXlab platform
Torben Lykke Sorensen - One of the best experts on this subject based on the ideXlab platform.
-
Tachyphylaxis during treatment of exudative age related macular degeneration with ranibizumab
British Journal of Ophthalmology, 2012Co-Authors: Maria Salling Eghoj, Torben Lykke SorensenAbstract:AIM: To determine whether Tachyphylaxis occurs during treatment with ranibizumab (Lucentis, Genentech, Inc., South San Francisco, California, USA) for exudative age-related macular degeneration (AMD). DESIGN: Retrospective review of cases. PARTICIPANTS: The treatment results of 1076 eyes (976 patients) treated with ranibizumab for exudative AMD was evaluated to identify patients with a potential tachyphylactic response. The participants had to have a minimum of 12 months follow-up. METHODS: Tachyphylaxis was defined as a lack of response to the drug at the time of reactivation of choroidal neovascularisation (CNV) in patients who had responded to the initial treatment. The authors considered it a lack of response to ranibizumab if a decrease in vision and an increase in central retinal thickness (CRT) were observed despite repeated injections. Hence a stabilisation in vision and/or stabilisation in CRT during treatment were not considered Tachyphylaxis, and other unfavourable responses such as a tear in the retinal pigment epithelium and therefore a decrease in vision during treatment were also not considered as Tachyphylaxis. Every patient in this cohort who has had an injection-free interval after primary inactivation of CNV and who has received retreatment at a later stage was identified. In this population, those cases that did not respond to retreatment (Tachyphylaxis) were identified and characterised. MAIN OUTCOME MEASURES: Number of patients who developed Tachyphylaxis after treatment with ranibizumab. RESULTS: 20 patients (2%) developed Tachyphylaxis during their treatment. CONCLUSION: Tachyphylaxis can occur during the treatment of exudative AMD with ranibizumab. The precise mechanism for the development of Tachyphylaxis is unclear. Both local and systemic factors might be involved.
Daniel Lamontagne - One of the best experts on this subject based on the ideXlab platform.
-
role of nitric oxide and protein kinase c in the Tachyphylaxis to vasopressin in rat aortic rings
Life Sciences, 2005Co-Authors: Christine Hamel, Esther Millette, Daniel LamontagneAbstract:Abstract The contribution of endothelium-derived mediators and protein kinase C in the Tachyphylaxis to arginine vasopressin (AVP) was assessed in the rat aorta. Endothelium-intact (E+) and denuded rings (E−) obtained from the rat thoracic aorta were exposed to three administrations of a supramaximal concentration of AVP (100 nM), lasting 20 min and 45 min apart. N -Ω-nitro- l -arginine (NNLA), a non-selective inhibitor of all isoforms of NO synthase, and AMT, a selective inhibitor for the inducible (iNOS) and neuronal (nNOS) isoforms, diminished the Tachyphylaxis to AVP significantly in both E+ and in E− rings. No iNOS could be detected by Western blots in freshly isolated rings or in rings exposed to AVP, despite a strong signal in rings isolated from LPS-treated rats, while nNOS could be constitutively detected. Inhibition of prostaglandins or epoxyeicosatrienoic acids (EETs) synthesis by diclofenac or clotrimazole, respectively, had no effect on Tachyphylaxis while combination of these agents diminished Tachyphylaxis in E+ only. Combination of NNLA, diclofenac and clotrimazole blocked completely the Tachyphylaxis. Inhibition of PKC by either chelerythrine or bisindolylmaleimide I-HCl (BisI) led to a significant diminution of AVP Tachyphylaxis only in E−. Activation of PKC with phorbol-12-myristate-13-acetate (PMA) simulated Tachyphylaxis to AVP in E− only, effect blocked by the NO donor, SNP. In conclusion, NO produced from constitutive nNOS present in vascular smooth muscle cells participates in Tachyphylaxis to AVP. PKC is involved in this Tachyphylaxis only in E− rings, the presence of NO probably diminishing the effects of this kinase.
Stefan Grunder - One of the best experts on this subject based on the ideXlab platform.
-
permeating protons contribute to Tachyphylaxis of the acid sensing ion channel asic 1a
The Journal of Physiology, 2007Co-Authors: Xuanmao Chen, Stefan GrunderAbstract:The homomeric acid-sensing ion channel 1a (ASIC1a) is a H+-activated ion channel with important physiological functions and pathophysiological impact in the central nervous system. Here we show that homomeric ASIC1a is distinguished from other ASICs by a reduced response to successive acid stimulations. Such a reduced response is called Tachyphylaxis. We show that Tachyphylaxis depends on H+ permeating through ASIC1a, that Tachyphylaxis is attenuated by extracellular Ca2+, and that Tachyphylaxis is probably linked to Ca2+ permeability of ASIC1a. Moreover, we provide evidence that Tachyphylaxis is probably due to a long-lived inactive state of ASIC1a. A deeper understanding of ASIC1a Tachyphylaxis may lead to pharmacological control of ASIC1a activity that could be of potential benefit for the treatment of stroke.
Kohji Nishida - One of the best experts on this subject based on the ideXlab platform.
-
Tachyphylaxis during treatment of exudative age related macular degeneration with aflibercept
Graefes Archive for Clinical and Experimental Ophthalmology, 2019Co-Authors: Chikako Hara, Taku Wakabayashi, Yoko Fukushima, Kaori Sayanagi, Ryo Kawasaki, Shigeru Sato, Hirokazu Sakaguchi, Kohji NishidaAbstract:At present, the standard treatment of neovascular age-related macular degeneration (AMD) is the repeated administration of antivascular endothelial growth factor (VEGF) agents. However, we often encounter patients who develop Tachyphylaxis for anti-VEGF agents. In this study, we investigated the characteristics of patients who developed Tachyphylaxis on repeated intravitreal aflibercept (IVA) injections for neovascular AMD and the frequency of Tachyphylaxis. Three hundred thirteen eyes (313 patients) with treatment-naive AMD who achieved resolution soon after starting IVA and were followed up for ≥ 12 months were enrolled in this retrospective, interventional, consecutive case series. The eyes were investigated for Tachyphylaxis to aflibercept. Tachyphylaxis was defined as absence of any improvement (more than 100 μm) in or worsening of CRT within 1 month after more than two repeated monthly IVA injections when the exudative change remained. Twenty-eight (8.9%) of the 313 eyes developed Tachyphylaxis (occult with no classic, n = 14; polypoidal choroidal vasculopathy, n = 14) at an annual rate of about 3%. The mean number of IVA injections was 10.5 ± 7.8, and the mean interval until Tachyphylaxis was 20.9 ± 14.0 months. There was a significant difference in the AMD subtypes between the group with Tachyphylaxis and the group without it (p = 0.0029). Occult with no classic type and polypoidal choroidal vasculopathy were the only AMD subtypes in the eyes with Tachyphylaxis. In the analysis of the eyes that had occult with no classic or polypoidal choroidal vasculopathy, only intraretinal edema was significantly less common (p = 0.042). A combination of photodynamic therapy and aflibercept was effective in 13 (87%) of 15 eyes with Tachyphylaxis, and switching to intravitreal ranibizumab was effective in 5 (56%) of 9 eyes. Tachyphylaxis occurs after repeated IVA injections in a minority of patients with AMD for a long term and is more likely to occur in eyes with lesions beneath the retinal pigment epithelium and no intraretinal edema. Treatment of AMD should be performed keeping this fact in mind, while considering the consecutive treatment.
Brian J. Lipworth - One of the best experts on this subject based on the ideXlab platform.
-
fluticasone reverses oxymetazoline induced Tachyphylaxis of response and rebound congestion
American Journal of Respiratory and Critical Care Medicine, 2010Co-Authors: S. Vaidyanathan, K L Clearie, Peter A Williamson, Faisel Khan, Brian J. LipworthAbstract:Rationale: Chronic use of intranasal decongestants, such as oxymetazoline, leads to Tachyphylaxis of response and rebound congestion, caused by α-adrenoceptor mediated down-regulation and desensitization of response.Objectives: We evaluated if Tachyphylaxis can be reversed by intranasal fluticasone propionate, and the relative α1- and α2-adrenoceptor components of Tachyphylaxis using the α1-antagonist prazosin.Methods: In a randomized, double-blind, placebo-controlled, crossover design, 19 healthy subjects received intranasal oxymetazoline, 200 μg three times a day for 14 days, followed by the addition of fluticasone, 200 μg twice a day for a further 3 days. At Days 1, 14, and 17, participants received a single dose of oral prazosin, 1 mg, or placebo with measurements made before and 2 hours later.Measurements and Main Results: Outcomes evaluated were peak nasal inspiratory flow, nasal resistance, blood flow, and oxymetazoline dose–response curve (DRC). On Day 14 versus Day 1, inspiratory flow decreased (...
