Evaluation of the efficiency of a new hollow fiber plasmapheresis filter.

Plasma separation for plasma exchange or plasma treatment has, until now, been obtained prevalently by centrifugal separators. Recently, filters capable of continuously separating the plasma have been proposed. We have evaluated, both in vivo and ex vivo, the efficiency of a plasma separating filter (BT 900, Dideco, Mirandola, Italy) incorporating polypropylene hollow fibers with a pore size of 0.

Energy cost of walking with lesions of the foot.

The oxygen consumption during walking was measured in patients affected by chronic lesions of the foot. Only subjects with rigidity of the talocalcaneal joint showed increased oxygen consumption, which reached 5 to 20 per cent above normal. They also showed an increased step frequency, probably as a compensatory mechanism to reduce the mechanical work performed during each step.

A simple relation between performance in running and maximal aerobic power.

As the cost of running amounts to about 1 cal per m covered and per kg of body weight, when the aerobic power (VO2, ml/min kg) is known and the energy from glycolysis assumed to be about equal to the energy from oxidations in 1 min, the time employed to cover a given distance can be predicted: a nomogram is given to facilitate the calculation. Conversely from the time employed to cover a given distance the aerobic power in VO2, ml/kg times min can be calculated.

The role played by elasticity in an exercise involving movements of small amplitude.

In an exercise consisting of repetitive small jumps on both feet at a frequency of 116/min, the mechanical work performed and the O2 consumption at steady state were measured. Of the positive work performed in the jump only 40% appears to be due to the chemical transformations taking place in the contractile componenet of the muscle fibres; the remaining 60% appears to be due to the elastic energy accumulated in the elastic elements of the contracted stretched muscles of the lower limbs during the falling phase of the previous jump, when the body hits the ground.