We investigated age-related changes to fascicle length, sarcomere length and serial sarcomere number (SSN), and how this affects passive force. Following mechanical testing to determine passive force, the medial gastrocnemius muscle of young (n=9) and old (n=8) Fisher 344BN hybrid rats was chemically fixed at the optimal muscle length for force production; individual fascicles were dissected for length measurement, and laser diffraction was used to assess sarcomere length. Old rats had ∼14% shorter fascicle lengths than young rats, which was driven by a ∼10% reduction in SSN, with no difference in sarcomere length (∼4%). Passive force was greater in the old than in the young rats at long muscle lengths. Shorter fascicle lengths and reduced SSN in the old rats could not entirely explain increased passive forces for absolute length changes, owing to a slight reduction in sarcomere length in old rats, resulting in similar sarcomere length at long muscle lengths.

PurposeWe assessed the effectiveness and safety of a 5-day intravenous prostaglandin (iloprost) protocol at reducing digital amputation for patients with severe frostbite injuries at urban emergency departments. Methods This retrospective study examines consecutive patients who presented to Calgary emergency departments from April 2017 to April 2020 with Grade 2-4 frostbite injuries. Patients from February 2019 onward were managed using a 5-day iloprost infusion protocol, whereas patients prior to this time were managed with standard care (local best practice without iloprost as a therapeutic option). The primary effectiveness outcome was rate of affected digits amputated, stratified by frostbite severity. The secondary safety outcome was the incidence of serious adverse events associated with iloprost (allergic reactions or symptomatic hypotension requiring treatment or discontinuation of the infusion). Results 90 patients were included, 26 were treated with iloprost, compared to 64 patients who received usual care. Both the treatment and usual care groups experienced substantial rates of homelessness and substance use. No digital amputations were required for patients with Grade 2 injuries in either group, but significantly lower digital amputation rates were observed for patients with more severe frostbite injuries treated with iloprost versus usual care: Grade 3 (18% vs 44%, p < 0.001), Grade 4 (46% vs 95%, p < 0.001). No serious adverse events were associated with iloprost. Conclusion In this unselected socially complex urban population, administration of iloprost for patients with frostbite was shown to be safe and was associated with lower digital amputation rates, particularly for those with more severe injuries. Keywords Frostbite • Hypothermia • Cold injuries • Iloprost • Prostaglandin RésuméObjectif Nous avons évalué l'efficacité et la sécurité d'un protocole de 5 jours de prostaglandine intraveineuse (iloprost) pour réduire l'amputation digitale chez les patients souffrant d'engelures graves dans les services d'urgence urbains. Méthodes Cette étude rétrospective examine des patients consécutifs qui se sont présentés aux services d'urgence de Calgary d'avril 2017 à avril 2020 avec des engelures de niveau 2 à 4. À compter de février 2019, les patients ont été traités au moyen d'un protocole de perfusion d'iloprost de 5 jours, tandis que les patients avant cette période ont été pris en charge avec des soins standard (meilleures pratiques locales sans iloprost comme option thérapeutique). Le principal résultat d'efficacité était le taux de doigts affectés amputés, stratifié selon la gravité des gelures. Le critère secondaire de sécurité était l'incidence

We investigated age-related changes to fascicle length (FL), sarcomere length (SL), and serial sarcomere number (SSN), and how this affects passive force. Following mechanical testing to determine passive force, the medial gastrocnemius muscle of young (n=9) and old (n=8) Fisher 344BN hybrid rats was chemically fixed at the optimal muscle length for force production; individual fascicles were dissected for length measurement, and laser diffraction was used to assess SL. Old rats had ∼14% shorter FL than young, which was driven by a ∼10% reduction in SSN, with no difference in SL (∼4%). Passive force was greater in the old compared to young rats at long muscle lengths. Shorter FL and reduced SSN in the old rats could not entirely explain increased passive forces for absolute length changes, owing to a slight reduction in SL in old, resulting in similar SL at long muscle lengths.Summary StatementThis study sought to explain the increased passive tension observed for muscles of older individuals owing to age-related changes to muscle architecture.

To determine the prevalence of PE in patients hospitalized for a first episode of syncope.

No abstract