[Clinical application of LED pattern visual evoked potential].

The light emitting diode (LED) stimulator was used to record PVEP from 59 eyes (38 patients) with optic neuropathy and 46 eyes (23 patients) with cataract. The amplitude and the latency of P100 in LED PVEP were comparable to those in TV PVEP with insignificant differences (P > 0.05), suggesting that LED PVEP may be used in the evaluation of visual function and prognosis of patients with optic neuropathy or cataract.

Acute responses to experimental blunt head trauma: topography of white matter edema.

The location of edema and territory of extravasation of serum protein were examined in the white matter of cats with different forms of intracranial pathology following an impact-acceleration injury to the head. Edema was tested with an organic density gradient and Evans blue dye was used as a marker for breakdown of the blood-brain barrier. Animals with tissue hemorrhage (contusions) involving both cerebral cortex and white matter had a substantial, progressive accumulation of Evans blue-stained edema near tissue hemorrhage during the 6 h following trauma. In addition, this category of cats had a widespread, mild edema at 15 min after injury that was usually unaccompanied by Evans blue stain. Cats with cortical contusions had rather mild edema neighboring tissue hemorrhage; animals with subarachnoid hemorrhage in the absence of cerebral contusions had neither measurable edema nor (usually) visible Evans blue staining. We conclude that: acute traumatic cerebral edema varies considerably in presence, magnitude and territory with different forms of intracranial pathology; and mechanically induced edema can occur that is independent of spread of fluid from areas of tissue hemorrhage.