Down Syndrome and Other Chromosome Abnormalities

This book provides a concise yet comprehensive source of current information on Down syndrome and other chromosomal abnormalities. Research workers, scientists, medical graduates and paediatricians will find it an excellent source for reference and review. Key features of this book are as follows: • Mechanisms of aneuploidy. • Effect of sociodemographic factors on different congenital disorders. • Haematological malignancies and congenital heart disease in Down syndrome. • Prenatal screening, management and counselling to detect Down syndrome and other chromosomal abnormalities. While aimed primarily at research workers on Down syndrome and different types of chromosomal disorders, we hope that the appeal of this book will extend beyond the narrow confines of academic interest and be of interest to a wider audience, especially the parents and relatives of children suffering from Down syndrome and other chromosomal abnormality syndromes

Changes in nuclear protein acetylation in u.v.-damaged human cells

We have investigated the levels of nuclear protein acetylation in u.v.-irradiated human fibroblasts. Initially, we measured the levels of acetylation in total acid-soluble nuclear proteins and observed two distinct differences between the irradiated and unirradiated (control) cells. Immediately after irradiation, there is a 'wave' of protein hyperacetylation (i.e. a total acetylation level greater than that of unirradiated cells) that lasts for 2-6 h depending on the experimental conditions. This hyperacetylation phase is then followed by a hypoacetylation phase, lasting for many hours, and the total level of acetylation does not return to that of control cells until 24-72 h after u.v. damage. Both the magnitude and duration of each phase is dependent on the dose of u.v. light used. The wave of hyperacetylation is more pronounced at low u.v. doses (i.e. less than 5 J/m2), while the wave of hypoacetylation is more pronounced at higher u.v. doses (greater than or equal to 8 J/m2). Furthermore, the duration of each phase is prolonged when cells are exposed to 2 mM hydroxyurea, an agent which retards the rate of excision repair at u.v.-damaged sites. Examination of the acetylation levels of the individual nuclear proteins indicated that acetylation of the core histones follows the same pattern observed for the total acid-soluble protein fractions. Furthermore, these were the only major proteins in the total acid-soluble fraction observed to undergo the early, rapid hyperacetylation immediately following u.v. damage. Acetylation of histone H1 was negligible in both damaged and control cells, while three prominent non-histone proteins were acetylated only after long labeling times (greater than 4 h) in each case, gradually becoming hyperacetylated in the u.v.-damaged cells. These results raise the possibility that a causal relationship exists between nuclear protein acetylation and nucleotide excision repair of DNA in human cells.LR: 20061115; PUBM: Print; GR: 1 1H-2940-8751/PHS; GR: ES02614/ES/NIEHS; JID: 8008055; 0 (Acetic Acids); 0 (Chromosomal Proteins, Non-Histone); 0 (Nucleoproteins); 56-87-1 (Lysine); 64-19-7 (Acetic Acid); ppublishSource type: Electronic(1