Pragmatic exercise intervention for people with multiple sclerosis (ExIMS Trial): Study protocol for a randomised controlled trial

Exercise is an effective intervention for improving function, mobility and health-related quality of life in people with multiple sclerosis (PwMS). Questions remain however, regarding the effectiveness of pragmatic exercise interventions for evoking tangible and sustained increases in physical activity and long-term impact on important health outcomes in PwMS. Furthermore, dose-response relationships between exercise and health outcomes have not previously been reported in PwMS. These issues, and improved knowledge of cost effectiveness, are likely to influence key decisions of health policy makers regarding the implementation of exercise therapy as part of the patient care pathway for PwMS. Hence, the primary aim of this study is to investigate whether a 12-week tapered programme of supervised exercise, incorporating cognitive-behavioural techniques to facilitate sustained behaviour change, is effective for evoking improvements in physical activity and key health outcomes in PwMS over 9months of follow-up. A total of 120 PwMS will be randomised (1:1) to either a 12-week pragmatic exercise therapy intervention or usual care control group. Participants will be included on the basis of a clinical diagnosis of MS, with an expanded disability status score (EDSS) between 1 and 6.5. Outcome measures, to be assessed before and after the intervention and 6months later, will include physical activity, clinical and functional measures and health-related quality of life. In addition, the cost effectiveness of the intervention will be evaluated and dose-response relationships between physical activity and the primary/secondary outcomes in those with mild and more severe disease will be explored

Trade-offs and synergies in the structural and functional characteristics of leaves photosynthesizing in aquatic environments

Aquatic plants, comprising different divisions of embryophytes, derive from terrestrial ancestors. They have evolved to live in water, both fresh and salty, an environment that presents unique challenges and opportunities for photosynthesis and growth. These include, compared to air, a low water stress, a greater density, and attenuation of light, and a more variable supply of inorganic carbon, both in concentration and chemical species, but overall a lower carbon availability, and the opportunity to take up nutrients from the water. The leaves of many aquatic plants are linear, dissected, whorled, or cylindrical with a large volume of air spaces. They tend to have a high specific leaf area, thin cuticles, and usually lack functional stomata. Exploiting the availability of chemicals in their environment, freshwater macrophytes may incorporate silica in their cell wall, while seagrasses contain sulphated polysaccharides, similar to those of marine macroalgae; both groups have low lignin content. This altered cell wall composition produces plants that are more flexible and therefore more resistant to hydraulic forces (mechanical stress arising from water movement). Aquatic plants may have enhanced light harvesting complexes conferring shade adaptation, but also have mechanisms to cope with high light. Aquatic plants have evolved numerous strategies to overcome potential carbon-limitation in water. These include growing in micro-environments where CO2 is high, producing leaves and roots that exploit CO2 from the air or sediment and operating concentrating mechanisms that increase CO2 (CCM) around the primary carboxylating enzyme, ribulose-1,5-bisphosphate carboxylase-oxygenase. These comprise C4 metabolism, crassulacean acid metabolism, and the ability to exploit the often high concentrations of HCO3−, and ~50% of freshwater macrophytes and ~85% of seagrasses have one or more CCM. Many of these adaptations involve trade-offs between conflictin constraints and opportunities while others represent ‘synergies’ that help to maximize the productivity of this important group of plants