Plasma angiogenesis and oxidative stress markers in patients with diabetic retinopathy.

Background: Neovascularization in the retina and hyperglycaemia-induced oxidative stress are implicated in the pathogenesis of diabetic retinopathy (DR). In this study, we hypothesized that the plasma angiogenic and oxidative stress markers associated with these derangements could aid in the screening of diabetic patients who are at an increased risk of developing retinopathy.Methods: This study included normal (n = 148), type2 diabetes without retinopathy (DNR; n = 148), proliferative DR (PDR; n = 74) and non-PDR (NPDR; n = 148) subjects. Plasma concentrations of vascular endothelial growth factor-A (VEGF-A), hypoxia-inducible factor-1α (HIF-1α), matrix metalloproteinase-9 (MMP-9), pigment epithelium-derived factor (PEDF), nitric oxide (NO), soluble receptors for advanced glycation end products (sRAGE), malondialdehyde (MDA) and protein thiols were estimated.Results: A statistically significant increase was observed in the plasma concentrations of pro-angiogenic factors and markers of oxidative stress in both retinopathy groups. By contrast, the concentrations of anti-angiogenic factors and antioxidants were decreased significantly in these groups. Receiver operating characteristic analysis indicated that the plasma thresholds of HIF-1α and PEDF can be suitable markers in case of NPDR. However, in PDR, HIF-1α, NO, MMP-9 and PEDF showed high sensitivity and specificity.Conclusions: The factors associated with hypoxia, matrix degradation and angiogenic inhibition play a crucial role in predicting DR.

Analysis of the DNA sequence and duplication history of human chromosome 15.

Here we present a finished sequence of human chromosome 15, together with a high-quality gene catalogue. As chromosome 15 is one of seven human chromosomes with a high rate of segmental duplication, we have carried out a detailed analysis of the duplication structure of the chromosome. Segmental duplications in chromosome 15 are largely clustered in two regions, on proximal and distal 15q; the proximal region is notable because recombination among the segmental duplications can result in deletions causing Prader-Willi and Angelman syndromes. Sequence analysis shows that the proximal and distal regions of 15q share extensive ancient similarity. Using a simple approach, we have been able to reconstruct many of the events by which the current duplication structure arose. We find that most of the intrachromosomal duplications seem to share a common ancestry. Finally, we demonstrate that some remaining gaps in the genome sequence are probably due to structural polymorphisms between haplotypes; this may explain a significant fraction of the gaps remaining in the human genome.

DNA sequence and analysis of human chromosome 8.

The International Human Genome Sequencing Consortium (IHGSC) recently completed a sequence of the human genome. As part of this project, we have focused on chromosome 8. Although some chromosomes exhibit extreme characteristics in terms of length, gene content, repeat content and fraction segmentally duplicated, chromosome 8 is distinctly typical in character, being very close to the genome median in each of these aspects. This work describes a finished sequence and gene catalogue for the chromosome, which represents just over 5% of the euchromatic human genome. A unique feature of the chromosome is a vast region of approximately 15 megabases on distal 8p that appears to have a strikingly high mutation rate, which has accelerated in the hominids relative to other sequenced mammals. This fast-evolving region contains a number of genes related to innate immunity and the nervous system, including loci that appear to be under positive selection--these include the major defensin (DEF) gene cluster and MCPH1, a gene that may have contributed to the evolution of expanded brain size in the great apes. The data from chromosome 8 should allow a better understanding of both normal and disease biology and genome evolution.