A quasi-elastic light scattering study of smooth muscle myosin in the presence of ATP

We have investigated the hydrodynamic properties of turkey gizzard smooth muscle myosin in solution using quasi-elastic light scattering (QELS). The effects of ionic strength (0.05–0.5 M KCl) and light chain phosphorylation on the conformational transition of myosin were examined in the presence of ATP at 20 degrees C. Cumulant analysis and light scattering models were used to describe the myosin system in solution. A nonlinear least squares fitting procedure was used to determine the model that best fits the data. The conformational transition of the myosin monomer from a folded form to an extended form was clearly demonstrated in a salt concentration range of 0.15–0.3 M KCl. Light chain phosphorylation regulates the transition and promotes unfolding of the myosin. These results agree with the findings obtained using sedimentation velocity and electron microscopy (Onishi and Wakabayashi, 1982; Trybus et al., 1982; Trybus and Lowey, 1984). In addition, we present evidence for polymeric myosin coexisting with the two monomeric myosin species over a salt concentration range from 0.05 to 0.5 M KCl. The size of the polymeric myosin varied with salt concentration. This observation supports the hypothesis that, in solution, a dynamic equilibrium exists between the two conformations of myosin monomer and filaments

Illustrative quotes indicating collective action.

For many people with advanced osteoarthritis, total knee replacement is an effective treatment to relieve pain and improve function. However, 10–34% of people experience chronic postsurgical pain in the months and years after total knee replacement. The Support and Treatment After Replacement (STAR) randomised controlled trial (ISCRTN92545361) evaluated the clinical- and cost-effectiveness of a new multifaceted and personalised care pathway, compared with usual care, for people with pain at three months after total knee replacement. Our objective was to identify factors promoting or inhibiting its implementation, and to inform future training and wider implementation of the pathway. We conducted a prospective process evaluation using qualitative interviews with eight Extended Scope Practitioners and six Principal Investigators from seven trial sites who were involved in delivering the STAR care pathway during the trial. We used Normalization Process Theory as a theoretical framework for qualitative data collection and content analysis. We identified that factors promoting the implementation of the pathway were quick familiarisation with the pathway, valuing patient-centredness, formalising referral processes, and increasing confidence to address neuropathic pain. Challenges to implementation were availability of time and resources, sensitivity in referral process, and ensuring collective understanding of the pathway. These findings have enabled us to make recommendations about the future implementation of the STAR care pathway and will inform the development of a training package, and updated manual for successful delivery in usual care. Furthermore, this model of care has potential value in diverse elective surgeries and pain conditions.</div

Illustrative quotes indicating the normalization potential of STAR.

Illustrative quotes indicating the normalization potential of STAR.</p

STAR implementation interviews topic guide.

For many people with advanced osteoarthritis, total knee replacement is an effective treatment to relieve pain and improve function. However, 10–34% of people experience chronic postsurgical pain in the months and years after total knee replacement. The Support and Treatment After Replacement (STAR) randomised controlled trial (ISCRTN92545361) evaluated the clinical- and cost-effectiveness of a new multifaceted and personalised care pathway, compared with usual care, for people with pain at three months after total knee replacement. Our objective was to identify factors promoting or inhibiting its implementation, and to inform future training and wider implementation of the pathway. We conducted a prospective process evaluation using qualitative interviews with eight Extended Scope Practitioners and six Principal Investigators from seven trial sites who were involved in delivering the STAR care pathway during the trial. We used Normalization Process Theory as a theoretical framework for qualitative data collection and content analysis. We identified that factors promoting the implementation of the pathway were quick familiarisation with the pathway, valuing patient-centredness, formalising referral processes, and increasing confidence to address neuropathic pain. Challenges to implementation were availability of time and resources, sensitivity in referral process, and ensuring collective understanding of the pathway. These findings have enabled us to make recommendations about the future implementation of the STAR care pathway and will inform the development of a training package, and updated manual for successful delivery in usual care. Furthermore, this model of care has potential value in diverse elective surgeries and pain conditions.</div

Illustrative quotes indicating cognitive participation.

Illustrative quotes indicating cognitive participation.</p

Illustrative quotes indicating coherence.

For many people with advanced osteoarthritis, total knee replacement is an effective treatment to relieve pain and improve function. However, 10–34% of people experience chronic postsurgical pain in the months and years after total knee replacement. The Support and Treatment After Replacement (STAR) randomised controlled trial (ISCRTN92545361) evaluated the clinical- and cost-effectiveness of a new multifaceted and personalised care pathway, compared with usual care, for people with pain at three months after total knee replacement. Our objective was to identify factors promoting or inhibiting its implementation, and to inform future training and wider implementation of the pathway. We conducted a prospective process evaluation using qualitative interviews with eight Extended Scope Practitioners and six Principal Investigators from seven trial sites who were involved in delivering the STAR care pathway during the trial. We used Normalization Process Theory as a theoretical framework for qualitative data collection and content analysis. We identified that factors promoting the implementation of the pathway were quick familiarisation with the pathway, valuing patient-centredness, formalising referral processes, and increasing confidence to address neuropathic pain. Challenges to implementation were availability of time and resources, sensitivity in referral process, and ensuring collective understanding of the pathway. These findings have enabled us to make recommendations about the future implementation of the STAR care pathway and will inform the development of a training package, and updated manual for successful delivery in usual care. Furthermore, this model of care has potential value in diverse elective surgeries and pain conditions.</div

Additional file 2: of Development of a complex intervention for people with chronic pain after knee replacement: the STAR care pathway

Overview of STAR assessment clinic appointment, telephone follow-up and recommended treatment referral pathways. (DOCX 18 kb

Additional file 1: of Clinical- and cost-effectiveness of the STAR care pathway compared to usual care for patients with chronic pain after total knee replacement: study protocol for a UK randomised controlled trial

SPIRIT checklist. (DOCX 23 kb