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https://www.readbyqxmd.com/read/28533393/angular-measurements-of-the-dynein-ring-reveal-a-stepping-mechanism-dependent-on-a-flexible-stalk
#1
Lisa G Lippert, Tali Dadosh, Jodi A Hadden, Vishakha Karnawat, Benjamin T Diroll, Christopher B Murray, Erika L F Holzbaur, Klaus Schulten, Samara L Reck-Peterson, Yale E Goldman
The force-generating mechanism of dynein differs from the force-generating mechanisms of other cytoskeletal motors. To examine the structural dynamics of dynein's stepping mechanism in real time, we used polarized total internal reflection fluorescence microscopy with nanometer accuracy localization to track the orientation and position of single motors. By measuring the polarized emission of individual quantum nanorods coupled to the dynein ring, we determined the angular position of the ring and found that it rotates relative to the microtubule (MT) while walking...
May 22, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28529762/enhanced-inter-subject-brain-computer-interface-with-associative-sensorimotor-oscillations
#2
Simanto Saha, Khawza I Ahmed, Raqibul Mostafa, Ahsan H Khandoker, Leontios Hadjileontiadis
Electroencephalography (EEG) captures electrophysiological signatures of cortical events from the scalp with high-dimensional electrode montages. Usually, excessive sources produce outliers and potentially affect the actual event related sources. Besides, EEG manifests inherent inter-subject variability of the brain dynamics, at the resting state and/or under the performance of task(s), caused probably due to the instantaneous fluctuation of psychophysiological states. A wavelet coherence (WC) analysis for optimally selecting associative inter-subject channels is proposed here and is being used to boost performances of motor imagery (MI)-based inter-subject brain computer interface (BCI)...
February 2017: Healthcare Technology Letters
https://www.readbyqxmd.com/read/28521140/distinct-sources-of-deterministic-and-stochastic-components-of-action-timing-decisions-in-rodent-frontal-cortex
#3
Masayoshi Murakami, Hanan Shteingart, Yonatan Loewenstein, Zachary F Mainen
The selection and timing of actions are subject to determinate influences such as sensory cues and internal state as well as to effectively stochastic variability. Although stochastic choice mechanisms are assumed by many theoretical models, their origin and mechanisms remain poorly understood. Here we investigated this issue by studying how neural circuits in the frontal cortex determine action timing in rats performing a waiting task. Electrophysiological recordings from two regions necessary for this behavior, medial prefrontal cortex (mPFC) and secondary motor cortex (M2), revealed an unexpected functional dissociation...
May 17, 2017: Neuron
https://www.readbyqxmd.com/read/28515687/effects-of-passive-finger-movement-on-cortical-excitability
#4
Masaki Nakagawa, Ryoki Sasaki, Shota Tsuiki, Shota Miyaguchi, Sho Kojima, Kei Saito, Yasuto Inukai, Hideaki Onishi
This study examined the effects of joint angle and passive movement direction on corticospinal excitability. The subjects were 14 healthy adults from whom consent could be obtained. We performed two experiments. In Experiment 1, we measured motor evoked potential (MEP) amplitude, F-wave and M-wave at 0° and 20° adduction during adduction or abduction movement, in the range of movement from 10° abduction to 30° adduction. In Experiment 2, MEPs were measured at static 0° and 20° adduction during passive adduction from 10° adduction to 30° adduction and static 20° adduction...
2017: Frontiers in Human Neuroscience
https://www.readbyqxmd.com/read/28511261/current-practice-and-the-future-of-deep-brain-stimulation-therapy-in-parkinson-s-disease
#5
Leonardo Almeida, Wissam Deeb, Chauncey Spears, Enrico Opri, Rene Molina, Daniel Martinez-Ramirez, Aysegul Gunduz, Christopher W Hess, Michael S Okun
Deep brain stimulation (DBS) is an effective therapy for Parkinson's disease patients experiencing motor fluctuations, medication-resistant tremor, and/or dyskinesia. Currently, the subthalamic nucleus and the globus pallidus internus are the two most widely used targets, with individual advantages and disadvantages influencing patient selection. Potential DBS patients are selected using the few existing guidelines and the available DBS literature, and many centers employ an interdisciplinary team review of the individual's risk-benefit profile...
April 2017: Seminars in Neurology
https://www.readbyqxmd.com/read/28511252/diagnosis-and-management-of-parkinson-s-disease
#6
Arjun Tarakad, Joseph Jankovic
Despite numerous efforts to identify specific and sensitive biomarkers, the diagnosis of Parkinson's disease (PD) is still based on clinical criteria that include the presence of a combination of cardinal motor features (tremor, rigidity, bradykinesia, and postural instability), other motor features (including freezing of gait and abnormal postures), and numerous nonmotor features. In addition, the presence of atypical features may suggest an alternative diagnosis. Levodopa therapy remains the gold standard in the management of motor features of PD...
April 2017: Seminars in Neurology
https://www.readbyqxmd.com/read/28505208/neuromuscular-function-of-the-quadriceps-muscle-during-isometric-maximal-submaximal-and-submaximal-fatiguing-voluntary-contractions-in-knee-osteoarthrosis-patients
#7
Anett Mau-Moeller, Robert Jacksteit, Mario Jackszis, Frank Feldhege, Matthias Weippert, Wolfram Mittelmeier, Rainer Bader, Ralf Skripitz, Martin Behrens
INTRODUCTION: Knee osteoarthrosis (KOA) is commonly associated with a dysfunction of the quadriceps muscle which contributes to alterations in motor performance. The underlying neuromuscular mechanisms of muscle dysfunction are not fully understood. The main objective of this study was to analyze how KOA affects neuromuscular function of the quadriceps muscle during different contraction intensities. MATERIALS AND METHODS: The following parameters were assessed in 20 patients and 20 healthy controls: (i) joint position sense, i...
2017: PloS One
https://www.readbyqxmd.com/read/28504022/safinamide-for-the-treatment-of-parkinson-s-disease
#8
Ruth Mary deSouza, Anthony Schapira
The major unmet needs in the medical treatment of Parkinson disease (PD) are reduction of motor side effects from dopaminergic drugs, management of non-motor symptoms and disease modification. Areas covered: Motor fluctuations and OFF periods are a significant determinant of quality of life in PD and reducing their duration and severity can significantly improve motor function. This aim may be partly facilitated by the development of effective adjunctive drugs for dopamine replacement. Safinamide (Xadago), which is a first generation anticonvulsant, has pharmacological properties which are of interest in the context of neurodegenerative diseases, leading to research into its potential as an adjunct to levodopa in PD...
May 23, 2017: Expert Opinion on Pharmacotherapy
https://www.readbyqxmd.com/read/28497554/shaking-up-the-debate-ensuring-the-ethical-use-of-dbs-intervention-criteria-for-mid-stage-parkinson-s-patients
#9
REVIEW
Marleen Eijkholt, Laura Y Cabrera, Adolfo Ramirez-Zamora, Julie G Pilitsis
OBJECTIVES: Deep brain stimulation (DBS) is a well-established treatment for the management of severe motor fluctuations in advanced Parkinson's disease (PD). Until recently, device regulation, medical, and insurance practices limited DBS to patients with advanced stages of PD. In February 2016 this changed, however, when the US Food and Drug Administration (FDA) granted formal approval for the use of brain stimulator in mid-stage PD patients. In this article, we examine whether DBS in mid-stage PD can be ethically justified beyond the FDA approval...
May 11, 2017: Neuromodulation: Journal of the International Neuromodulation Society
https://www.readbyqxmd.com/read/28495972/multiple-transient-signals-in-human-visual-cortex-associated-with-an-elementary-decision
#10
Thomas Meindertsma, Niels A Kloosterman, Guido Nolte, Andreas K Engel, Tobias H Donner
The cerebral cortex continuously undergoes changes in its state, which manifest in transient modulations of the cortical power spectrum. Cortical state changes occur also at full wakefulness, during rapid cognitive acts, such as perceptual decisions. Previous studies found a global modulation of beta-band (12-30 Hz) activity in human and monkey visual cortex during an elementary visual decision: reporting the appearance or disappearance of salient visual targets surrounded by a distractor. The previous studies did neither disentangle the motor action associated with behavioral report, nor other secondary processes, such as arousal, from perceptual decision processing per se...
May 11, 2017: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/28494962/nuclear-positioning-and-its-translational-dynamics-are-regulated-by-cell-geometry
#11
A V Radhakrishnan, Doorgesh S Jokhun, Saradha Venkatachalapathy, G V Shivashankar
The collective activity of several molecular motors and other active processes generate large forces for directional motion within the cell, which is vital for a multitude of cellular functions such as migration, division, contraction, transport, and positioning of various organelles. These processes also generate a background of fluctuating forces, which influence intracellular dynamics and thereby create unique biophysical signatures, which are altered in many diseases. In this study, we have used the nucleus as a probe particle to understand the microrheological properties of altered intracellular environments by using micropatterning to confine cells in two structurally and functionally extreme geometries...
May 9, 2017: Biophysical Journal
https://www.readbyqxmd.com/read/28494958/integrated-analysis-of-intracellular-dynamics-of-menainv-cancer-cells-in-a-3d-matrix
#12
Michael Mak, Sarah Anderson, Meghan C McDonough, Fabian Spill, Jessica E Kim, Alexandra Boussommier-Calleja, Muhammad H Zaman, Roger D Kamm
The intracellular environment is composed of a filamentous network that exhibits dynamic turnover of cytoskeletal components and internal force generation from molecular motors. Particle tracking microrheology enables a means to probe the internal mechanics and dynamics. Here, we develop an analytical model to capture the basic features of the active intracellular mechanical environment, including both thermal and motor-driven effects, and show consistency with a diverse range of experimental microrheology data...
May 9, 2017: Biophysical Journal
https://www.readbyqxmd.com/read/28494719/levodopa-in-parkinson-s-disease-current-status-and-future-developments
#13
N Tambasco, M Romoli, P Calabresi
Ever since the pioneering reports in the 60s, L-3,4-Dioxyphenylalanine (levodopa) has represented the gold standard for the treatment of Parkinson's Disease (PD). However, long-term levodopa (LD) treatment is frequently associated with fluctuations in motor response, often challenging to resolve, with serious impact on patients quality of life. The pharmacokinetic and pharmacodynamics properties of LD are pivotal to such motor fluctuations: discontinuous drug delivery, short half-life, poor bioavailability, and narrow therapeutic window are all crucial for such fluctuations...
May 10, 2017: Current Neuropharmacology
https://www.readbyqxmd.com/read/28472620/bidirectionality-from-cargo-thermal-fluctuations-in-motor-mediated-transport
#14
Christopher E Miles, James P Keener
Molecular motor proteins serve as an essential component of intracellular transport by generating forces to haul cargoes along cytoskeletal filaments. Two species of motors that are directed oppositely (e.g. kinesin, dynein) can be attached to the same cargo, which is known to produce bidirectional net motion. Although previous work focuses on the motor number as the driving noise source for switching, we propose an alternative mechanism: cargo diffusion. A mean-field mathematical model of mechanical interactions of two populations of molecular motors with cargo thermal fluctuations (diffusion) is presented to study this phenomenon...
May 1, 2017: Journal of Theoretical Biology
https://www.readbyqxmd.com/read/28471751/significance-tests-on-the-output-power-of-a-thermally-driven-rotary-nanomotor
#15
Likui Yang, Kun Cai, Jiao Shi, Qing H Qin
Many factors can have a significant influence on the output power of a thermally driven rotary nanomotor made of carbon nanotubes (CNTs). Making use of a computational molecular dynamics approach, we evaluate for the first time the output power of a nanomotor, considering some of the main factors including temperature, the diameter of the rotor and the number of IRD atoms (N) on the stator. When applying extra-resistant torque to the rotor to let the stable value of the rotational frequency of the rotor fluctuate near zero, the value of the resistant torque can be considered as the output power of the rotor...
May 26, 2017: Nanotechnology
https://www.readbyqxmd.com/read/28465860/lrrk2-g2019s-mutation-prevalence-and-clinical-features-in-moroccans-with-parkinson-s-disease
#16
Ahmed Bouhouche, Houyam Tibar, Rafiqua Ben El Haj, Khalil El Bayad, Rachid Razine, Sanaa Tazrout, Asmae Skalli, Naima Bouslam, Loubna Elouardi, Ali Benomar, Mohammed Yahyaoui, Wafa Regragui
Background. The LRRK2 G2019S mutation is the most common genetic determinant of Parkinson's disease (PD) identified to date. This mutation, reported in both familial and sporadic PD, occurs at elevated frequencies in Maghreb population. In the present study, we examined the prevalence of the G2019S mutation in the Moroccan population and we compared the motor and nonmotor phenotype of G2019S carriers to patients with idiopathic Parkinson's disease. Methods. 100 PD patients were assessed for motor and nonmotor symptoms, current medication, and motor complication including motor fluctuations and dyskinesia...
2017: Parkinson's Disease
https://www.readbyqxmd.com/read/28459677/continuous-assessment-of-levodopa-response-in-parkinson-s-disease-using-wearable-motion-sensors
#17
Christopher L Pulliam, Dustin A Heldman, Elizabeth B Brokaw, Thomas O Mera, Zoltan K Mari, Michelle A Burack
OBJECTIVE: Fluctuations in response to levodopa in Parkinson's disease (PD) are difficult to treat as tools to monitor temporal patterns of symptoms are hampered by several challenges. The objective was to use wearable sensors to quantify the dose response of tremor, bradykinesia, and dyskinesia in individuals with PD. METHODS: Thirteen individuals with PD and fluctuating motor benefit were instrumented with wrist and ankle motion sensors and recorded by video. Kinematic data were recorded as subjects completed a series of activities in a simulated home environment through transition from OFF to ON medication...
April 25, 2017: IEEE Transactions on Bio-medical Engineering
https://www.readbyqxmd.com/read/28428905/deep-brain-stimulation-target-selection-in-an-advanced-parkinson-s-disease-patient-with-significant-tremor-and-comorbid-depression
#18
Amar S Patel
CLINICAL VIGNETTE: A 67-year-old female with advanced Parkinson's disease (PD), medically refractory tremor, and a history of significant depression presented for evaluation of deep brain stimulation (DBS) candidacy. CLINICAL DILEMMA: Traditionally, the subthalamic nucleus (STN) has been preferred over the globus pallidus interna (GPi) as a DBS target for PD patients with levodopa-responsive fluctuations in rigidity and akinesia, for whom tremor is also a significant source of impairment...
2017: Tremor and Other Hyperkinetic Movements
https://www.readbyqxmd.com/read/28416144/feasibility-of-spirography-features-for-objective-assessment-of-motor-function-in-parkinson-s-disease
#19
Aleksander Sadikov, Vida Groznik, Martin Možina, Jure Žabkar, Dag Nyholm, Mevludin Memedi, Dejan Georgiev
OBJECTIVE: Parkinson's disease (PD) is currently incurable, however proper treatment can ease the symptoms and significantly improve the quality of life of patients. Since PD is a chronic disease, its efficient monitoring and management is very important. The objective of this paper was to investigate the feasibility of using the features and methodology of a spirography application, originally designed to detect early Parkinson's disease (PD) motoric symptoms, for automatically assessing motor symptoms of advanced PD patients experiencing motor fluctuations...
March 31, 2017: Artificial Intelligence in Medicine
https://www.readbyqxmd.com/read/28413401/parkinsonism-in-association-with-dihydropteridine-reductase-deficiency
#20
Yoshiaki Takahashi, Yasuhiro Manabe, Yumiko Nakano, Taijun Yunoki, Syoichiro Kono, Hisashi Narai, Mahoko Furujo, Koji Abe
We report a 16-year-old man with disorders of tetrahydrobiopterin metabolism due to dihydropteridine reductase (DHPR) deficiency. He revealed moderate mental retardation, parkinsonism, and spastic paralysis with levodopa and 5-hydroxytryptophan (5-HTP) supplementation from the age of 2 months. Brain MRI showed high intensity areas in bilateral frontal and posterior deep white matter on fluid-attenuated inversion recovery (FLAIR). Coronal FLAIR image showed a high signal in bilateral pyramidal tracts. Single photon computed tomography (SPECT) imaging of the dopamine transporter was normal...
January 2017: Case Reports in Neurology
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