Abstract

The enzymatic cleavage of a peptide amphiphile (PA) is investigated. The self-assembly of the cleaved products is distinct from that of the PA substrate. The PA C16-KKFFVLK is cleaved by α-chymotrypsin at two sites leading to products C16-KKF with FVLK and C16-KKFF with VLK. The PA C16-KKFFVLK forms nanotubes and helical ribbons at room temperature. Both PAs C16-KKF and C16-KKFF corresponding to cleavage products instead self-assemble into 5–6 nm diameter spherical micelles, while peptides FVLK and VLK do not adopt well-defined aggregate structures. The secondary structures of the PAs and peptides are examined by FTIR and circular dichroism spectroscopy and X-ray diffraction. Only C16-KKFFVLK shows substantial β-sheet secondary structure, consistent with its self-assembly into extended aggregates, based on PA layers containing hydrogen-bonded peptide headgroups. This PA also exhibits a thermoreversible transition to twisted tapes on heating.

Highlights

  • It is estimated that 85% of stroke survivors sustain upper limb hemiparesis (Thorngren and Westling, 1990) with 30–60% experiencing permanent impairments of motor function (van der Lee, 2003)

  • Significant improvements in all behavioral measures were observed after therapy for all participants (N = 31; MAL–Amount of Use (AoU) (t(30) = 5.8, p b .001); MAL–Quality of Movement (QoM): (t(30) = 7.6, p b .001); WMFT–Functional Ability Score (FAS) (t(30) = 4.3, p b .001); WMFT–Time Taken (TT) (z = −3.3; p = .001))

  • Treatment outcome was not affected by the constraint condition as indicated by insignificant group differences for MAL–AoU (t(29) = 0.5, p = .6), MAL–QoM: (t(29) = 1.4, p = .2); WMFT–FAS (t(29) = 0.5, p = .6; and WMFT–TT (t(29) = −0.2, p = .8))

Read more

Summary

Introduction

It is estimated that 85% of stroke survivors sustain upper limb hemiparesis (Thorngren and Westling, 1990) with 30–60% experiencing permanent impairments of motor function (van der Lee, 2003). The discovery of adult brain plasticity, together with the emergence of positive evidence for motor function improvement through repetitive training and practice, has driven a paradigm shift in the treatment of motor deficits after stroke (French et al, 2007; Taub et al, 2002). This is evidenced by several systematic reviews Nijland et al, 2011; Peurala et al, 2012; Sirtori et al, 2009), and multi-centered trials (e.g. EXCITE, Wolf et al, 2007; Wolf et al, 2010) which suggest sustainable improvements of upper limb function through CI-therapy or its derivatives This is evidenced by several systematic reviews (e.g. Nijland et al, 2011; Peurala et al, 2012; Sirtori et al, 2009), and multi-centered trials (e.g. EXCITE, Wolf et al, 2007; Wolf et al, 2010) which suggest sustainable improvements of upper limb function through CI-therapy or its derivatives (e.g. Page, 2007; Sterr and Freivogel, 2003)

Objectives
Methods
Results
Discussion
Conclusion
Full Text
Paper version not known

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call

Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.