G Loizou | PubMed Health

PubMed1998

An AI approach to dynamic visual field testing.

Visual field test results are crucial to the accuracy and efficiency of diagnosing blinding diseases such as glaucoma. Herein, a method of integrating self-organizing neural networks and empirical heuristics is used to perform visual field tests via a dynamic test strategy, which can lead to a reduction in the number of trials in a perimetric test. Experiments performed using clinical test records show that we are able to reduce by 20% to 30% the number of trials per test without much adverse effect on the accuracy of the tests.

Algorithms↗

PubMed1988

Circadian variation in the uptake of tryptophan by cortical synaptosomes of the rat brain.

The kinetics of the high affinity uptake system for L-tryptophan (L-Try) have been measured over 24 hr in cortical synaptosome preparations of rat brain. Both the Km and Vmax of the uptake process showed a statistically significant 24 hr variation. The highest Km value, 6.71 X 10(-5) M, was measured at the beginning of the light phase and the lowest value, 4.23 X 10(-5) M, 6 hr into the dark phase. Vmax was highest at the end of the dark phase (10.43 nmol/mg/5 min) and lowest (4.80 nmol/mg/5 min) 3 hr into the dark phase. In contrast, there was no variation over 24 hr in the Vmax/Km ratio. These results suggest that the high affinity uptake process serves to ensure a constant rate of L-tryptophan entry into the neuron in the face of circadian or ultradian variations in extracellular concentration of tryptophan.

Animals↗