Impairment of the ability of the injured aged brain in elevating urate and ascorbate.

Urate and ascorbate play a major role in the defense mechanism of the brain against oxidative damage induced by traumatic brain injury. The severity and extent of brain damage are known to increase with age. This may be due to different basal levels of endogenous antioxidants, and/or to impaired ability of the old brain to recruit and elevate the levels of antioxidants following injury.

Guided bone regeneration in the treatment of segmental diaphyseal defects: a comparison between resorbable and non-resorbable membranes.

This study compares non-absorbable, ethyl cellulose (EC) membranes and absorbable, chitosan (CH) membranes in a rabbit model. Bone regeneration, evaluated by radiological and pathological parameters, was seen in both groups. In the EC group the process was faster but was followed by a sharp decrease, whereas in the CH group it was slower and continuous.