1;Preface;5 2;Contents;7 3;List of Contributors;19 4;1 Human Chromosomes: Structural and Functional Aspects;25 4.1;Abstract;25 4.2;1.1 History of Chromosome Research;26 4.3;1.2 Composition and Compartmentalization of Human Chromosomes;28 4.4;1.3 The Human Karyotype and Clinical Cytogenetics;29 4.5;1.4 Cell Cycle and Chromosome Cycle;33 4.6;1.5 Shaping the Metaphase Chromosome;34 4.7;1.6 Cohesion and Condensins;35 4.8;1.7 DNA Repair;37 4.9;1.8 Mendelian Disorders Affecting Chromosome Integrity;38 4.10;References;41 5;2 DNA Lesions Induced by Ionizing Radiation;45 5.1;Abstract;45 5.2;2.1 Introduction;45 5.3;2.2 Energy Deposition by Ionizing Radiation;47 5.4;2.3 Direct and Indirect Effect;48 5.5;2.4 Cerenkov Radiation;49 5.6;2.5 Hole and Electron Transfer Through DNA;49 5.7;2.6 Formation of Base Radicals;49 5.8;2.7 Base Damage;51 5.9;2.8 Single-Strand Breaks;54 5.10;2.9 Double Lesions;55 5.11;2.10 DNA-DNA Cross-Links;58 5.12;2.11 DNA-Protein Cross-Links;58 5.13;2.12 Clustered Lesions Beyond Double Lesions;58 5.14;2.13 Oxygen Effect and Chemical Repair;58 5.15;2.14 DNA Damage by UV-C and Ionizing Radiation - a Comparison;59 5.16;References;60 6;3 Effects of Ultraviolet Radiation on DNA;63 6.1;Abstract;63 6.2;3.1 Introduction;63 6.3;3.2 Primary Photoproducts in DNA;66 6.4;3.3 Action Spectra;68 6.5;3.4 Reversal and Repair of Primary Photoproducts;70 6.6;3.5 Cytological Effects;71 6.7;3.6 Conclusions;75 6.8;References;75 7;4 Double Strand Break Repair Mechanisms in Mammalian Cells;78 7.1;Abstract;78 7.2;4.1 Introduction;78 7.3;4.2 NHEJ Reaction;79 7.4;4.3 DSB Repair by HRR;82 7.5;4.4 Impaired DSB Repair and Chromosomal Aberrations;84 7.6;4.5 Fragile Sites Are Associated with DNA DSBs;85 7.7;4.6 Conclusions;86 7.8;References;86 8;5 Backup Pathways of Nonhomologous End Joining May Have a Dominant Role in the Formation of Chromosome Aberrations;89 8.1;Abstract;89 8.2;5.1 Introduction;89 8.3;5.2 Pathways of DSB Repair;91 8.4;5.3 Homology-Independent End Joining and Chromosome Aberration Formation;99 8.5;5.4 DSBs, NHEJ and Theories of Chromosome Aberration Formation;100 8.6;References;105 9;6 Targeted and Non-Targeted Induction of Chromosomal Rearrangements After Exposure to Ionizing Radiation;108 9.1;Abstract;108 9.2;6.1 Introduction;108 9.3;6.2 Radiation-Induced Chromosomal Instability;109 9.4;6.3 The Death-Inducing Effect;111 9.5;6.4 Chromosomal Instability Induced by DIE Medium from Unstable Clones;114 9.6;6.5 A Role for Non-Targeted Bystander Effects in Radiation- Induced Chromosomal Instability;114 9.7;6.6 Implications of Non-Targeted Effects for Cytogenetic Biodosimetry;115 9.8;6.7 Conclusions;116 9.9;References;116 10;7 DNA Methylation Damage: Formation, Repair and Biological Consequences;120 10.1;Abstract;120 10.2;7.1 Methylating Agents as Environmental Carcinogens;120 10.3;7.2 Anticancer Drugs;121 10.4;7.3 DNA Lesions, Sites of Attack;122 10.5;7.4 Repair of DNA Methylation Damage;125 10.6;7.5 Mechanism of Mutagenicity and Carcinogenicity;129 10.7;7.6 Mechanism of Cytotoxicity of Methylating Agents by Apoptosis;130 10.8;7.7 Mechanism of Formation of SCEs and Aberrations;132 10.9;References;136 11;8 Adducts, Sister-Chromatid Exchanges and Mutations Following Benzo[ a] pyrene Exposure: a Review of Quantitative Data Followed by Some Considerations Regarding Risk;143 11.1;Abstract;143 11.2;8.1 Introduction;143 11.3;8.2 Methodological Approach;144 11.4;8.3 Results;145 11.5;8.4 Discussion;152 11.6;References;158 12;9 Analysis of DNA Double-Strand Breaks by Means of .-H2AX Foci;164 12.1;Abstract;164 12.2;9.1 Introduction;164 12.3;9.2 Histone H2AX;165 12.4;9.3 Repair and Checkpoint Factors Are Recruited into y-H2AX Foci;168 12.5;9.4 Early DSB Rejoining Can Proceed Without Foci Formation;169 12.6;9.5 Foci May Be Present Long After DSB Are Rejoined;169 12.7;9.6 Practical Aspects of .-H2AX Estimation;170 12.8;9.7 Concluding Remarks;176 12.9;References;177 13;10 Comet Assay;180 13.1;Abstract;180 13.2;10.1 Introduction;180 13.3;10.2 Method;18