ABSTRACT
Purpose: To analyze the weekly rate of retinal vascular growth in treatment?na飗e babies with various stages of retinopathy of prematurity (ROP) and validate if this could be a predictor of treatment need. Methods: Retrospective review of medical charts and retinal images of babies with various stages of ROP. The images were enhanced using red?green image enhancement software. Using the length of the horizontal disc diameter (DD) of each eye, the vessel growth was measured from the disc margin up to the vessel tip in fixed quadrants. The rate of vessel growth was the ratio of vessel length to the number of weeks it took to reach this length. The babies were divided into treatment warranting ROP (group 1), low?risk pre?threshold (type II) ROP (group 2,), and no?ROP (group 3) for analysis. The 搉o?ROP� group acted as normal control. Group 1 was further subdivided into 1A (threshold ROP), IB (aggressive posterior ROP), 1C (hybrid ROP), and ID (high?risk pre?threshold ROP). Results: Out of 436 eyes, groups 1, 2, and 3 had 238, 108, and 90 eyes, respectively. The mean rate of vascular outgrowth along with 95% confidence interval (CI) was 0.490 [0.487,0.520], 0.612 [0.599, 0.638], and 0.719 [0.703, 0.740] DD/week, respectively, for babies with 搕reatment warranting,� 搇ow risk pre?threshold� and 搉o ROP� groups, respectively. In our estimate, more than 80% of eyes with a vessel growth rate of 0.54 DD/week or less required treatment. Conclusion: A rate of retinal vascular growth less than 0.54 DD/week can be used to determine treatment requirements in babies with ROP
ABSTRACT
The antioxidant activity of C-Phycocyanin (C-PC) isolated from three cyanobacterial species Lyngbya (marine), Phormidium (marine) and Spirulina (fresh water) was studied in vitro. The results demonstrate that C-PCs from Lyngbya, Phormidium and Spirulina spp. are able to scavenge peroxyl radicals (determined by crocin bleaching assay) with relative rate constant ratio of 3.13, 1.89 and 1.8, respectively. C-PCs also scavenge hydroxyl radicals (determined by deoxyribose degradation assay) with second order rate constant values of 7.87 x 10(10), 9.58 x 10(10) and 6.42 x 10(10), respectively. Interestingly, Lyngbya C-PC is found to be an effective inhibitor of peroxyl radicals (IC50 6.63 microM), as compared to Spirulina (IC50 12.15 microM) and Phormidium C-PC (IC50 12.74 microM) and is close to uric acid (IC50 2.15 microM). Further, the studies suggest that the covalently-linked tetrapyrrole chromophore phycocyanobilin is involved in the radical scavenging activity of C-PC. The electron spin resonance (ESR) spectra of C-PCs indicate the presence of free radical active sites, which may play an important role in its radical scavenging property. This is the first report on the ESR activity of native C-PCs without perturbations that can cause radical formation.