Migration of myogenic cells in the rat extensor digitorum longus muscle studied with a split autograft model

The ability of myogenic cells to migrate perpendicular to the long axis of freely autografted muscles was examined. Rat extensor digitorum longus muscles were divided, and one half was devitalized by repeated freezing in liquid nitrogen while the other half was kept viable in physiologic saline. The halves were reunited with sutures and grafted back into the original muscle bed. At intervals between 5 and 25 days the grafts were removed and examined histologically for the presence of myotubes within the devitalized region. Myotubes were first seen in the devitalized half 10 days postgrafting with the maximum number of myotubes observed after 12 to 15 days. These results indicate that myogenic cells are capable of migration perpendicular to the long axis of the muscle fibers in an autograft.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47687/1/441_2004_Article_BF00327748.pd

Expérience de l'E.D.F. dans le domaine des prises d'eau de haute montagne à chasses automatiques

E.D.F. have acquired sufficient practical experience of automatic water intakes to be able to consider the problem as practically solved. As a water intake and its automatic system form a single homogeneous unit, automatic flushing can only be worth while if all the components from the river intake to the flushing channel are working properly. The following parts of the structure are reviewed : (i) The river intake (Figs 2 to 8) ; (ii) The settling tank (Figs 9, 10 and 11) ; (iii) The sluice gate (Fig 12) ; (iv) The flushing channel (Fig 13). The three following automatic systems of comparable efficiency are then described : System A with a conical silt detector, a rocking weir and a finely balanced sluice gate (Gigs 14 to 18) ; System B with a weighing detector, a differential pressure gauge and relay amplifier and a hydraulically-actuated sluice gate (Figs 19 to 23) ; A composite system combining A and B. Three representative water intakes are then described, all of which are based on the principles described in the article (Plans n° 1, 2 and 3). The following advantage of automatic operation in the considered case are emphasized : (i) Reduced supervision cost ; (ii) Better feasibility ; (iii) Reduced water loss