BACKGROUND: The current treatment of hereditary hemochromatosis (HH) consists of performing periodic whole blood phlebotomies. Erythrocytapheresis (EA) can remove up to three times more red blood cells per single procedure and could thus have a clinical benefit. A prospective study of 30 consecutive cases of HH were included in a periodic EA program. METHODS AND PATIENTS: EA were performed using a discontinuous flow cell separators. The protocol consisted of a bimonthly EA until normalization of the serum ferritin was reached. The aim was to reduce the total erythrocyte volume by 25-35%, eventually, to adjust the amount so that hematocrit would not drop below 0.25. RESULTS: 530 +/- 101 ml of erythrocytes were removed (median 517, range 116-761 ml). Iron depletion (ferritin < 20 microg/l) was achieved in all patients after a mean 6.9 +/- 7.6 months, median 5 months, range 1-36 months and a mean 14 EA sessions. The procedures were well tolerated and there were no severe side-effects. CONCLUSIONS: We conclude that HH patients treated with EA achieved iron depletion quickly under good conditions of tolerance. The efficacy, speed, tolerability, and more favorable schedule of an EA program facilitate treatment of HH. and V. Rehácek, M. Bláha, H. Jirousová, J. Cernohorská, P. Papousek
INTRODUCTION: The aim of this study was to find out the impact of degradation and regeneration of force over time at NiTi springs on the value and course of the final acting force and to verify the possibility of using these phenomena for a directed transition to the reverse plateau and its maintaining. METHODS: Static and cyclic mechanical loadings were performed. At first unused springs were tested. Afterwards the springs were mechanically stabilized by stress cycling and finally tested again. The difference in shape of the working curves was assessed. For simulation and description of the force degradation the modified Voight model was used. RESULTS: New springs, mainly those with large hysteresis, showed a significant stress-strain curve movement and shape changes during the cycling. The effect of the stress-strain curve course change disappeared fully in the stabilized springs. Multiple loading led to an overall decrease of force value during the measurement. The effect of force degradation and regeneration over time by simple static loading varies in the range of percentage of the nominal force in the plateau area. The transition between stress-strain curve phases caused by the degradation or regeneration of the force wasn't observed in case of mechanically stabilized springs. CONCLUSIONS: Springs should be mechanically stabilized before their application. The degree of force degradation over time is insignificant for mechanically stabilized springs. Degradation or regeneration of force over time, mechanical stabilization or micromovements in the mouth don't cause any transition between individual stress-strain curve phases. and A. Bezrouk, L. Balský, M. Smutný, T. Nosek, J. Záhora, J. Hanus, R. Polma