A novel and highly sensitive voltammetric enzyme-linked immunosensor was developed based on tyramine) oxidation deposition. It was shown that gold nano-particles(colloid Au) could be used as a platform to immobilize antibodies by adsorption. By a sandwich immunossary format with goat-anti-human IgG labled Horseradish peroxidase(HRP) as the second antibody and catalytic amplification by biotin-tyramine, the immunosensor′s) catalytic ability to hydrogen peroxide increased nearly 20 times), the sensor exhibitd a linear response to human IgG in the concentration range from 1.5 μg/L-22 mg/L, and the detection limit was 0.1 μg/L), the regression equation could be expressed as Δi_p(μA) =2.8859c(mg/L)+17.152 with a correlation) coefficient of 0.9872. The immunosensor can be used to quantitatively determine hIgG in the sample) of human serum).

AIM: To investigate the effect of ischemia induced by central retinal artery occlusion on retinal microstructure of macula using optical coherence tomography (OCT). METHODS: Fourteen eyes of 14 patients with unilateral central retinal artery occlusion (CRAO) in two to three days without fully recovery of retinal circulation underwent OCT examination with 4.5 mm length horizontal and vertical line scans through foveola to measure the retinal neurosensory layer (RNL) thickness on foveola, 175 ?m (fovea), 750 ?m (macula) to foveola, respectively. The other normal eyes of patients as control group underwent the same examination and measurement. RESULTS: The mean RNL thickness(?m) on foveola, fovea, macula were 169 91?10 96, 176 36?11 74 and 256 45?16 95 respectively in normal control eyes, and 235 64?47 02 , 241 84?49 36 and 401 57?54 53 respectively in CRAO eyes with retinal ischemia. There was a significant difference in thickness between two group ( P