Polyamines interact with hydroxyl radicals in activating Ca(2+) and K(+) transport across the root epidermal plasma membranes.

Reactive oxygen species (ROS) are integral components of the plant adaptive responses to environment. Importantly, ROS affect the intracellular Ca(2+) dynamics by activating a range of nonselective Ca(2+)-permeable channels in plasma membrane (PM). Using patch-clamp and noninvasive microelectrode ion flux measuring techniques, we have characterized ionic currents and net K(+) and Ca(2+) fluxes induced by hydroxyl radicals (OH(•)) in pea (Pisum sativum) roots. OH(•), but not hydrogen peroxide, activated a rapid Ca(2+) efflux and a more slowly developing net Ca(2+) influx concurrent with a net K(+) efflux. In isolated protoplasts, OH(•) evoked a nonselective current, with a time course and a steady-state magnitude similar to those for a K(+) efflux in intact roots. This current displayed a low ionic selectivity and was permeable to Ca(2+). Active OH(•)-induced Ca(2+) efflux in roots was suppressed by the PM Ca(2+) pump inhibitors eosine yellow and erythrosine B. The cation channel blockers gadolinium, nifedipine, and verapamil and the anionic channel blockers 5-nitro-2(3-phenylpropylamino)-benzoate and niflumate inhibited OH(•)-induced ionic currents in root protoplasts and K(+) efflux and Ca(2+) influx in roots. Contrary to expectations, polyamines (PAs) did not inhibit the OH(•)-induced cation fluxes. The net OH(•)-induced Ca(2+) efflux was largely prolonged in the presence of spermine, and all PAs tested (spermine, spermidine, and putrescine) accelerated and augmented the OH(•)-induced net K(+) efflux from roots. The latter effect was also observed in patch-clamp experiments on root protoplasts. We conclude that PAs interact with ROS to alter intracellular Ca(2+) homeostasis by modulating both Ca(2+) influx and efflux transport systems at the root cell PM.

[Comparison of three therapeutic exercises protocols to lumbar hyperlordosis improvement in asyntomatic youths]. / Comparación de tres protocolos de ejercicios terapéuticos para corrección de la hiperlordosis lumbar en jóvenes asintomáticos.

INTRODUCTION: One of the causes of low back pain is lumbar hyperlordosis. There are different protocols of therapeutic exercises for its correction, which do not involve all of corporal segments. A modified protocol is proposed, which involves all such segments. OBJECTIVE: To evaluate the efficacy of proposed protocol with two established protocols for correction of lumbar hyperlordosis. MATERIALS AND METHODS: Simple-blind clinical trial on 42 students of the Faculty of Medicine at University of Colima. The three protocols: A) Pérez-Olmedo (proposed, n = 14), B) Williams (n = 15) and C) Jeffrey Saal (n = 13) were randomly assigned. Clinical and radiological evaluations were performed. Lumbar hyperlordosis was considered when Ferguson's angle was > or = 30 degrees, measured on lateral spine x-ray pictures. During two months they underwent supervised and directed exercise sessions. The improvement in lumbar hyperlordosis correction of each protocol was compared through paired Student t-test and ANOVA. RESULTS: Average age was 18 +/- 0.9 years. Lumbar hyperlordosis frequency was 31% (n = 15). There was not significative difference on Ferguson's angle average comparation between three treatment groups. There was lumbar hyperlordosis improvement with following percentages: group A = 60%, Group B = 16% and group C = 0%. CONCLUSION: Protocol of therapeutic exercises proposed (Pérez-Olmedo) could be an alternative to lumbar hyperlordosis improvement in asyntomatic youhts.