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    A hyperbranched dopamine-containing PEG-based polymer for the inhibition of α-synuclein fibrillation
    (Orlando, Fla. : Academic Press, 2015) Breydo, Leonid; Newland, Ben; Zhang, Hong; Rosser, Anne; Werner, Carsten; Uversky, Vladimir N.; Wang, Wenxin
    Aggregation of α-synuclein is believed to play an important role in Parkinson's disease and in other neurodegenerative maladies. Small molecule inhibitors of this process are among the most promising drug candidates for neurodegenerative diseases. Dendrimers have also been studied for anti-fibrillation applications but they can be difficult and expensive to synthetize. Here we show that RAFT polymerization can be used to produce a hyperbranched polyethylene glycol structure via a one-pot reaction. This polymer included a dopamine moiety, a known inhibitor of α-synuclein fibril formation. Dopamine within the polymer structure was capable of aggregation inhibition, although not to the same degree as free dopamine. This result opens up new avenues for the use of controlled radical polymerizations as a means of preparing hyperbranched polymers for anti-fibrillation activity, but shows that the incorporation of functional groups from known small molecules within polymers may alter their biological activity.
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    Coupling between leg muscle activation and EEG during normal walking, intentional stops, and freezing of gait in Parkinson's disease
    (Lausanne : Frontiers Media, 2019) Günther, Moritz; Bartsch, Ronny P.; Miron-Shahar, Yael; Hassin-Baer, Sharon; Inzelberg, Rivka; Kurths, Jürgen; Plotnik, Meir; Kantelhardt, Jan W.
    In this paper, we apply novel techniques for characterizing leg muscle activation patterns via electromyograms (EMGs) and for relating them to changes in electroencephalogram (EEG) activity during gait experiments. Specifically, we investigate changes of leg-muscle EMG amplitudes and EMG frequencies during walking, intentional stops, and unintended freezing-of-gait (FOG) episodes. FOG is a frequent paroxysmal gait disturbance occurring in many patients suffering from Parkinson's disease (PD). We find that EMG amplitudes and frequencies do not change significantly during FOG episodes with respect to walking, while drastic changes occur during intentional stops. Phase synchronization between EMG signals is most pronounced during walking in controls and reduced in PD patients. By analyzing cross-correlations between changes in EMG patterns and brain-wave amplitudes (from EEGs), we find an increase in EEG-EMG coupling at the beginning of stop and FOG episodes. Our results may help to better understand the enigmatic pathophysiology of FOG, to differentiate between FOG events and other gait disturbances, and ultimately to improve diagnostic procedures for patients suffering from PD. Copyright © 2019 Günther, Bartsch, Miron-Shahar, Hassin-Baer, Inzelberg, Kurths, Plotnik and Kantelhardt.