Estimated lower speed boundary at which the walk ratio constancy is broken in healthy adults.

[Purpose] The ratio of step length to cadence (walk ratio) is invariant over a wide range of speeds. However, no studies have investigated details of the change in the walk ratio at slow speeds. It is necessary to explore how walking behavior changes at a low speed to understand the slow walking observed in various conditions such as aging and pathological conditions. In this study, changes in the walk ratio at slow speeds were investigated, and a lower boundary was estimated at which the walk ratio constancy is broken. [Subjects and Methods] Twenty-one healthy adults were instructed to walk along a flat, straight walkway at five different speeds (fast, preferred, slightly slow, slow, and very slow). The walk ratio was calculated from the step length and cadence. [Results] As the walking speed decreased, the walk ratio and variance began to increase abruptly. The initial break in the walk ratio constancy was at approximately 62 m/min. In addition, the boundary of cadence was approximately 98 m/steps/min. [Conclusions] The study successfully determined a lower boundary at which the walk ratio constancy was broken, suggesting that different control strategies are used when walking at less than the gait speed at which constancy is broken in healthy adults. The finding provides valuable information for understanding slow walking observed in individuals with various pathological conditions.

Transplantated mesenchymal stem cells derived from embryonic stem cells promote muscle regeneration and accelerate functional recovery of injured skeletal muscle.

We previously established that mesenchymal stem cells originating from mouse embryonic stem (ES) cells (E-MSCs) showed markedly higher potential for differentiation into skeletal muscles in vitro than common mesenchymal stem cells (MSCs). Further, the E-MSCs exhibited a low risk for teratoma formation. Here we evaluate the potential of E-MSCs for differentiation into skeletal muscles in vivo and reveal the regeneration and functional recovery of injured muscle by transplantation. E-MSCs were transplanted into the tibialis anterior (TA) muscle 24 h following direct clamping. After transplantation, the myogenic differentiation of E-MSCs, TA muscle regeneration, and re-innervation were morphologically analyzed. In addition, footprints and gaits of each leg under spontaneous walking were measured by CatWalk XT, and motor functions of injured TA muscles were precisely analyzed. Results indicate that >60% of transplanted E-MSCs differentiated into skeletal muscles. The cross-sectional area of the injured TA muscles of E-MSC-transplanted animals increased earlier than that of control animals. E-MSCs also promotes re-innervation of the peripheral nerves of injured muscles. Concerning function of the TA muscles, we reveal that transplantation of E-MSCs promotes the recovery of muscles. This is the first report to demonstrate by analysis of spontaneous walking that transplanted cells can accelerate the functional recovery of injured muscles. Taken together, the results show that E-MSCs have a high potential for differentiation into skeletal muscles in vivo as well as in vitro. The transplantation of E-MSCs facilitated the functional recovery of injured muscles. Therefore, E-MSCs are an efficient cell source in transplantation.

Mesenchymal stem cells originating from ES cells show high telomerase activity and therapeutic benefits.

We establish a novel method for the induction and collection of mesenchymal stem cells using a typical cell surface marker, CD105, through adipogenesis from mouse ES cells. ES cells were cultured in a medium for adipogenesis. Mesenchymal stem cells from mouse ES cells were easily identified by the expression of CD105, and were isolated and differentiated into multiple mesenchymal cell types. Mesenchymal stem cells showed remarkable telomerase activity and sustained their growth for a long time with a high potential for differentiation involving skeletal myogenesis in vitro. When mesenchymal stem cells were transplanted into the injured tibialis anterior muscles, they differentiated into skeletal muscle cells in vivo. In addition, they improved the vascular formation, but never formed teratoma for longer than 6 months. Gene expression profiles revealed that mesenchymal stem cells lost pluripotency, while they acquired high potential to differentiate into mesenchymal cell lines. They thus indicate a promising new source of cell-based therapy without teratoma formation.

The epidemiology of stroke amongst women in the Asia-Pacific region.

National data from the Asia-Pacific region suggest that stroke accounts for over 10% of female deaths. With general aging in the region, and longer life expectancies for women than men, action is required to maintain recent improvements in female death rates from stroke. However, local data on incidence and risk factors for stroke amongst women are scarce. Data from 214,032 women in the Asia Pacific Cohort Studies Collaboration were thus used to investigate the risk factors for stroke in the region. Raised systolic blood pressure and diabetes were found to be key risk factors for both ischemic (IS) and hemorrhagic (HS) stroke. After adjustment for other risk factors, every extra 10 mmHg systolic blood pressure increased risk of IS by 36% and HS by 69%, whilst diabetes increased risk of IS by 170% and HS by 147%. Smoking was also an important risk factor for IS and HS; risk was reduced by quitting.