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Hyperpolarization

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https://www.readbyqxmd.com/read/28087340/electrophysiological-alterations-in-diaphragm-muscle-caused-by-abdominal-ischemia-reperfusion
#1
Seckin Tuncer, Nizamettin Dalkilic, Ilksen Burat
Ischemia-reperfusion injury is the major complication of abdominal aortic surgery, and it mainly affects the lower extremities and remote organs. In the present study, the electrophysiological alterations in diaphragm that underlie the post-operative respiratory dysfunction were investigated. Wistar Albino rats were randomly divided into two groups: SHAM (only laparotomy was performed) and IR (abdominal aorta was clamped for 30min and reperfused for 2h). Following the operational period diaphragm muscles were isolated and electrophysiological experiments were carried out in-vitro...
January 10, 2017: Respiratory Physiology & Neurobiology
https://www.readbyqxmd.com/read/28079713/interrogating-idh-mutation-in-brain-tumor-magnetic-resonance-and-hyperpolarization
#2
Jingzhe Hu, Travis C Salzillo, Napapon Sailasuta, Frederick F Lang, Pratip Bhattacharya
Magnetic resonance spectroscopy (MRS) offers the possibility to noninvasively quantify 2HG concentration in the brain in the clinic, thereby serving as a valuable tool for patient-stratification as well as targeted treatment monitoring. Recently, hyperpolarized magnetic resonance techniques have opened up new opportunities for metabolic imaging not possible with conventional MRS in the brain. With over 10,000-fold increase in signal-to-noise ratio (SNR), dynamic metabolic processes can be interrogated in vivo with very high specificity by hyperpolarized MRI...
January 11, 2017: Topics in Magnetic Resonance Imaging: TMRI
https://www.readbyqxmd.com/read/28079471/pre-implant-modeling-of-depth-lead-placement-in-white-matter-for-maximizing-the-extent-of-cortical-activation-during-direct-neurostimulation-therapy
#3
Leopoldo Cendejas Zaragoza, Richard W Byrne, Marvin A Rossi
INTRODUCTION: The objective of this work was to predict preoperatively the maximum extent to which direct stimulation therapy can propagate through an epileptic circuit for stabilizing refractory focal-onset epilepsy. A pre-surgical workflow is presented which comprises a computationally intensive process for calculating the volume of cortical activation (VOCA) surrounding cylindrical depth contacts virtually placed in white matter. The process employs an activation function (AF) derived from cable modeling of an axon...
January 12, 2017: Neurological Research
https://www.readbyqxmd.com/read/28078839/widespread-membrane-potential-changes-and-cardiorespiratory-synchronization-involved-in-anxiety-and-sleep-wake-transitions
#4
R Jerath, S M Cearley, M Jensen
Located within the ascending reticular activating system are nuclei which release neurotransmitters such as acetylcholine, serotonin, dopamine, and norepinephrine. These nuclei have widespread projections that extend into the limbic system and throughout cortex. Activation of these neurotransmitters during awake states leads to arousal, while inhibition leads to the loss of consciousness experienced during slow-wave sleep. Previously, we proposed a mechanism in which cardiorespiratory synchronization may underlie the widespread hyperpolarization that occurs throughout the brain during slow-wave sleep...
October 2016: Journal of Biological Regulators and Homeostatic Agents
https://www.readbyqxmd.com/read/28077268/development-of-high-resolution-3d-hyperpolarized-carbon-13-mr-molecular-imaging-techniques
#5
Eugene Milshteyn, Cornelius von Morze, Galen D Reed, Hong Shang, Peter J Shin, Zihan Zhu, Hsin-Yu Chen, Robert Bok, Andrei Goga, John Kurhanewicz, Peder E Z Larson, Daniel B Vigneron
The goal of this project was to develop and apply techniques for T2 mapping and 3D high resolution (1.5 mm isotropic; 0.003 cm(3)) (13)C imaging of hyperpolarized (HP) probes [1-(13)C]lactate, [1-(13)C]pyruvate, [2-(13)C]pyruvate, and [(13)C,(15)N2]urea in vivo. A specialized 2D bSSFP sequence was implemented on a clinical 3T scanner and used to obtain the first high resolution T2 maps of these different hyperpolarized compounds in both rats and tumor-bearing mice. These maps were first used to optimize timings for highest SNR for single time-point 3D bSSFP acquisitions with a 1...
January 7, 2017: Magnetic Resonance Imaging
https://www.readbyqxmd.com/read/28074902/a-reduced-mechanical-model-for-camp-modulated-gating-in-hcn-channels
#6
Stephanie Weißgraeber, Andrea Saponaro, Gerhard Thiel, Kay Hamacher
We developed an in silico mechanical model to analyze the process of cAMP-induced conformational modulations in hyperpolarization-activated cyclic nucleotide-gated (HCN) channels, which conduct cations across the membrane of mammalian heart and brain cells. The structural analysis reveals a quaternary twist in the cytosolic parts of the four subunits in the channel tetramer. This motion augments the intrinsic dynamics of the very same protein structure. The pronounced differences between the cAMP bound and unbound form include a mutual interaction between the C-linker of the cyclic nucleotide binding domain (CNBD) and the linker between the S4 and S5 transmembrane domain of the channel...
January 11, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28074497/in-vivo-imaging-of-the-progression-of-acute-lung-injury-using-hyperpolarized-1-13-c-pyruvate
#7
Mehrdad Pourfathi, Yi Xin, Stephen J Kadlecek, Maurizio F Cereda, Harrilla Profka, Hooman Hamedani, Sarmad M Siddiqui, Kai Ruppert, Nicholas A Drachman, Jennia N Rajaei, Rahim R Rizi
PURPOSE: To investigate pulmonary metabolic alterations during progression of acute lung injury. METHODS: Using hyperpolarized [1-(13) C] pyruvate imaging, we measured pulmonary lactate and pyruvate in 15 ventilated rats 1, 2, and 4 h after initiation of mechanical ventilation. Lung compliance was used as a marker for injury progression. 5 untreated rats were used as controls; 5 rats (injured-1) received 1 ml/kg and another 5 rats (injured-2) received 2 ml/kg hydrochloric acid (pH 1...
January 11, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28072398/transportable-hyperpolarized-metabolites
#8
Xiao Ji, Aurélien Bornet, Basile Vuichoud, Jonas Milani, David Gajan, Aaron J Rossini, Lyndon Emsley, Geoffrey Bodenhausen, Sami Jannin
Nuclear spin hyperpolarization of (13)C-labelled metabolites by dissolution dynamic nuclear polarization can enhance the NMR signals of metabolites by several orders of magnitude, which has enabled in vivo metabolic imaging by MRI. However, because of the short lifetime of the hyperpolarized magnetization (typically <1 min), the polarization process must be carried out close to the point of use. Here we introduce a concept that markedly extends hyperpolarization lifetimes and enables the transportation of hyperpolarized metabolites...
January 10, 2017: Nature Communications
https://www.readbyqxmd.com/read/28071723/hcn1-channels-reduce-the-rate-of-exocytosis-from-a-subset-of-cortical-synaptic-terminals
#9
Zhuo Huang, Gengyu Li, Carolina Aguado, Rafael Lujan, Mala M Shah
The hyperpolarization-activated cyclic nucleotide-gated (HCN1) channels are predominantly located in pyramidal cell dendrites within the cortex. Recent evidence suggests these channels also exist pre-synaptically in a subset of synaptic terminals within the mature entorhinal cortex (EC). Inhibition of pre-synaptic HCN channels enhances miniature excitatory post-synaptic currents (mEPSCs) onto EC layer III pyramidal neurons, suggesting that these channels decrease the release of the neurotransmitter, glutamate...
January 10, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28069660/antioxidant-treatment-attenuates-lactate-production-in-diabetic-nephropathy
#10
Christoffer Laustsen, Per Mose Nielsen, Thomas Stokholm Nørlinger, Haiyun Qi, Uffe Kjærgaard Pedersen, Lotte Bonde Bertelsen, Jakob Appel Østergaard, Allan Flyvbjerg, Jan Henrik Ardenkjær-Larsen, Fredrik Palm, Hans Stødkilde-Jørgensen
The early progression of diabetic nephropathy is notoriously difficult to detect and quantify before the occurrence of substantial histological damage. Recently, hyperpolarized [1-(13)C]pyruvate has demonstrated increased lactate production in the kidney early after the onset of diabetes, implying increased lactate dehydrogenase activity as a consequence of increased nicotinamide adenine dinucleotide substrate availability due to upregulation of the polyol pathway, i.e., pseudohypoxia. In this study, we investigated the role of oxidative stress in mediating these metabolic alterations using state-of-the-art hyperpolarized magnetic resonance (MR) imaging...
January 1, 2017: American Journal of Physiology. Renal Physiology
https://www.readbyqxmd.com/read/28069411/age-related-alterations-of-neuronal-excitability-and-voltage-dependent-ca-2-current-in-a-spontaneous-mouse-model-of-alzheimer-s-disease
#11
Hua-Long Wang, Xiao-Hui Xian, Qiao-Yun Song, Chao Pang, Jia-Lei Wang, Ming-Wei Wang, Wen-Bin Li
Alzheimer's disease (AD) is the most common age-dependent neurodegenerative disorder, characterized by a progressive dysfunction of central neurons, and senescence-accelerated mouse prone 8 (SAMP8), a spontaneous AD mouse model, appears to be an excellent model to investigate the process of AD. Previous studies have indicated that neuronal excitability is impaired in transgenic AD mice. In this study, the cognition of SAMP8 mice was tested using the passive avoidance task and Morris water maze; whole-cell current-clamp recordings were used to evaluate the neuronal excitability, including the resting membrane potential, the number of action potentials, and after-hyperpolarization; and the voltage-dependent Ca(2+) current in hippocampal slices was measured using whole-cell voltage-clamp recordings...
January 6, 2017: Behavioural Brain Research
https://www.readbyqxmd.com/read/28067292/design-of-a-15-n-molecular-unit-to-achieve-long-retention-of-hyperpolarized-spin-state
#12
Hiroshi Nonaka, Masashi Hirano, Yuki Imakura, Yoichi Takakusagi, Kazuhiro Ichikawa, Shinsuke Sando
Nuclear hyperpolarization is a phenomenon that can be used to improve the sensitivity of magnetic resonance molecular sensors. However, such sensors typically suffer from short hyperpolarization lifetime. Herein we report that [(15)N, D14]trimethylphenylammonium (TMPA) has a remarkably long spin-lattice relaxation time (1128 s, 14.1 T, 30 °C, D2O) on its (15)N nuclei and achieves a long retention of the hyperpolarized state. [(15)N, D14]TMPA-based hyperpolarized sensor for carboxylesterase allowed the highly sensitive analysis of enzymatic reaction by (15)N NMR for over 40 min in phophate-buffered saline (H2O, pH 7...
January 9, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28066517/nmr-slic-sensing-of-hydrogenation-reactions-using-parahydrogen-in-low-magnetic-fields
#13
Danila A Barskiy, Oleg G Salnikov, Roman V Shchepin, Matthew A Feldman, Aaron M Coffey, Kirill V Kovtunov, Igor V Koptyug, Eduard Y Chekmenev
Parahydrogen-induced polarization (PHIP) is an NMR hyperpolarization technique that increases nuclear spin polarization by orders of magnitude, and it is particularly well-suited to study hydrogenation reactions. However, the use of high-field NMR spectroscopy is not always possible, especially in the context of potential industrial-scale reactor applications. On the other hand, the direct low-field NMR detection of reaction products with enhanced nuclear spin polarization is challenging due to near complete signal cancellation from nascent parahydrogen protons...
December 29, 2016: Journal of Physical Chemistry. C, Nanomaterials and Interfaces
https://www.readbyqxmd.com/read/28066143/acepromazine-inhibits-herg-potassium-ion-channels-expressed-in-human-embryonic-kidney-293-cells
#14
Young Shin Joo, Hong Joon Lee, Jin-Sung Choi, Ki-Wug Sung
The effects of acepromazine on human ether-à-go-go-related gene (hERG) potassium channels were investigated using whole-cell voltage-clamp technique in human embryonic kidney (HEK293) cells transfected with hERG. The hERG currents were recorded with or without acepromazine, and the steady-state and peak tail currents were analyzed for the evaluating the drug effects. Acepromazine inhibited the hERG currents in a concentration-dependent manner with an IC50 value of 1.5 µM and Hill coefficient of 1.1. Acepromazine blocked hERG currents in a voltage-dependent manner between -40 and +10 mV...
January 2017: Korean Journal of Physiology & Pharmacology
https://www.readbyqxmd.com/read/28066142/participation-of-central-gabaa-receptors-in-the-trigeminal-processing-of-mechanical-allodynia-in-rats
#15
Min Ji Kim, Young Hong Park, Kui Ye Yang, Jin Sook Ju, Yong Chul Bae, Seong Kyu Han, Dong Kuk Ahn
Here we investigated the central processing mechanisms of mechanical allodynia and found a direct excitatory link with low-threshold input to nociceptive neurons. Experiments were performed on male Sprague-Dawley rats weighing 230-280 g. Subcutaneous injection of interleukin 1 beta (IL-1β) (1 ng/10 µL) was used to produce mechanical allodynia and thermal hyperalgesia. Intracisternal administration of bicuculline, a gamma aminobutyric acid A (GABAA) receptor antagonist, produced mechanical allodynia in the orofacial area under normal conditions...
January 2017: Korean Journal of Physiology & Pharmacology
https://www.readbyqxmd.com/read/28065805/genetic-perturbations-suggest-a-role-of-the-resting-potential-in-regulating-the-expression-of-the-ion-channels-of-the-kcna-and-hcn-families-in-octopus-cells-of-the-ventral-cochlear-nucleus
#16
Xiao-Jie Cao, Donata Oertel
Low-voltage-activated K(+) (gKL) and hyperpolarization-activated mixed cation conductances (gh) mediate currents, IKL and Ih, through channels of the Kv1 (KCNA) and HCN families respectively and give auditory neurons the temporal precision required for signaling information about the onset, fine structure, and time of arrival of sounds. Being partially activated at rest, gKL and gh contribute to the resting potential and shape responses to even small subthreshold synaptic currents. Resting gKL and gh also affect the coupling of somatic depolarization with the generation of action potentials...
January 5, 2017: Hearing Research
https://www.readbyqxmd.com/read/28065276/using-imaging-as-a-biomarker-for-asthma
#17
REVIEW
Abhaya Trivedi, Chase Hall, Eric A Hoffman, Jason C Woods, David S Gierada, Mario Castro
There have been significant advancements in the various imaging techniques being used for the evaluation of asthmatic patients, both from a clinical and research perspective. Imaging characteristics can be used to identify specific asthmatic phenotypes and provide a more detailed understanding of endotypes contributing to the pathophysiology of the disease. Computed tomography, magnetic resonance imaging, and positron emission tomography can be used to assess pulmonary structure and function. It has been shown that specific airway and lung density measurements using computed tomography correlate with clinical parameters, including severity of disease and pathology, but also provide unique phenotypes...
January 2017: Journal of Allergy and Clinical Immunology
https://www.readbyqxmd.com/read/28064014/gpr55-agonist-lysophosphatidylinositol-and-lysophosphatidylcholine-inhibit-endothelial-cell-hyperpolarization-via-gpr-independent-suppression-of-na-ca-2-exchanger-and-endoplasmic-reticulum-ca-2-refilling
#18
Alexander I Bondarenko, Fabrizio Montecucco, Olga Panasiuk, Vadim Sagach, Nataliya Sidoryak, Karim J Brandt, François Mach
Lysophosphatidylinositol (LPI) and lysophosphatidylcholine (LPC) are lipid signaling molecules that induce endothelium-dependent vasodilation. In addition, LPC suppresses acetylcholine (Ach)-induced responses. We aimed to determine the influence of LPC and LPI on hyperpolarizing responses in vitro and in situ endothelial cells (EC) and identify the underlying mechanisms. Using patch-clamp method, we show that LPI and LPC inhibit EC hyperpolarization to histamine and suppress Na(+)/Ca(2+) exchanged (NCX) currents in a concentration-dependent manner...
January 4, 2017: Vascular Pharmacology
https://www.readbyqxmd.com/read/28062192/direct-effects-of-glucose-insulin-glp-1-and-gip-on-bulbospinal-neurons-in-the-rostral-ventrolateral-medulla-in-neonatal-wistar-rats
#19
Naoki Oshima, Hiroshi Onimaru, Hidehito Matsubara, Takahiro Uchida, Atsushi Watanabe, Toshihiko Imakiire, Yasuhiro Nishida, Hiroo Kumagai
Although patients with diabetes mellitus (DM) often exhibit hypertension, the mechanisms responsible for this correlation are not well known. We hypothesized that the bulbospinal neurons in the rostral ventrolateral medulla (RVLM) are affected by the levels of glucose, insulin, or incretins (glucagon like peptide-1 [GLP-1] or glucose-dependent insulinotropic peptide [GIP]) in patients with DM. To investigate whether RVLM neurons are activated by glucose, insulin, GLP-1, or GIP, we examined changes in the membrane potentials of bulbospinal RVLM neurons using whole-cell patch-clamp technique during superfusion with various levels of glucose or these hormones in neonatal Wistar rats...
January 3, 2017: Neuroscience
https://www.readbyqxmd.com/read/28061381/hyperpolarized-13-c-pyruvate-mouse-brain-metabolism-with-absorptive-mode-epsi-at-1t
#20
Vesselin Z Miloushev, Valentina Di Gialleonardo, Lucia Salamanca-Cardona, Fabian Correa, Kristin L Granlund, Kayvan R Keshari
The expected signal in echo-planar spectroscopic imaging experiments was explicitly modeled jointly in spatial and spectral dimensions. Using this as a basis, absorptive-mode type detection can be achieved by appropriate choice of spectral delays and post-processing techniques. We discuss the effects of gradient imperfections and demonstrate the implementation of this sequence at low field (1.05T), with application to hyperpolarized [1-(13)C] pyruvate imaging of the mouse brain. The sequence achieves sufficient signal-to-noise to monitor the conversion of hyperpolarized [1-(13)C] pyruvate to lactate in the mouse brain...
December 21, 2016: Journal of Magnetic Resonance
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