The evaluation of limb symmetry indices using ground reaction forces collected with one or two force plates in healthy dogs.

OBJECTIVE: To compare the variability of symmetry indices within and between days when using one and two force plates for data collection. ANIMALS: Seventeen healthy client-owned adult dogs. METHODS: Vertical ground reaction force data were collected in a crossover study design, with four collection sessions on two consecutive days, and then two weeks apart (days 1, 2, 15, and 16) using both 1-plate and 2-plate collection methods. Symmetry indices were calculated for limb pairs using two standard equations (SI1 and SI2). Repeated measures analysis was used to compare symmetry indices data between plate systems and days. Significance was set at p <0.05. RESULTS: There were no significant differences between plate systems for SI1 and SI2. There were no significant differences between data collected on different days and no significant interaction effects between variables. Symmetry indices were consistently larger for ground reaction forces calculated from non-consecutive footfalls. CONCLUSIONS: The use of two force plate systems will minimize variance caused by trial repetition and paired limb variation. When comparing SI1 to SI2, results were not significantly different. However, there were consistently higher mean values for SI1 compared with SI2 and symmetry indices were consistently larger for 1-plate systems compared to 2-plate systems for both symmetry indices.

Nitric oxide and Fenton/Haber-Weiss chemistry: nitric oxide is a potent antioxidant at physiological concentrations.

We have examined the action of nitric oxide (NO) on the ability of Fenton's reagent (ferrous iron and hydrogen peroxide), to oxidize a number of organic optical probes. We found that NO is able to arrest the oxidation of organic compounds at concentrations of NO found in brain, in vivo. We present evidence that Fenton's reagent proceeds via a ferryl intermediate ([Fe[double bond]O]2+), before the generation of hydroxyl radical *OH. NO reacts rapidly with this ferryl, blocking the production of *OH. We propose that NO has an important role in protecting biological tissues, and the brain in particular, from Fenton chemistry.