《carcinogenesis by ultraviolet light P340》

PART Ⅰ．INTRODUCTORY1

1．INTRODUCTION TO THE PROBLEM3

2．＂ULTRAVIOLET LIGHT＂：A PROBLEM IN DEFINITION9

Mode of Action of Light9

What is Meant by＂Ultraviolet Light＂？11

3．ABSORPTION OF ULTRAVIOLET LIGHT17

Absorption and Penetration in Living Systems17

Action Spectra and Absorption Spectra23

Sources of Ultraviolet Light30

Photochemical Consequences of Absorption34

PART Ⅱ．SOME EFFECTS OF ULTRAVIOLET LIGHT ON BIOLOGICAL SYSTEMS37

4．INACTIVATION AND LETHAL ACTION39

Inactivation of Enzymes39

Inactivation of Viruses44

Lethal Effects on Microorganisms48

Relation to Other Effects51

5．HEMOLYSIS：CYTOLYSIS：LYSOGENY52

Hemolysis52

Cytolysis and Permeability Changes in Complex Cells57

Lysogeny in Bacteria60

6．COMPARISON WITH EFFECTS OF OTHER TYPES OF RADIATION62

Photosensitized Oxidation(Photodynamic Action63

Effects of Ionizing Radiations68

O2-Dependence in Effects of Ultraviolet Light70

In Summary73

7．RECOVERY PROCESSES75

Photorecovery75

The Mechanism of Photorecovery79

＂Catalase＂Restoration85

In Summary86

8．REPLICATION AND CELL DIVISION88

Normal Cell Division89

The Energetics and Kinetics of Cell Growth and Replication of Parts90

The Mitotic Cycle96

Replication of DNA，RNA，and Protein Molecules100

Ultraviolet Light and the Timing of Cell Division103

Delay of Cleavage in the Sea Urchin Egg104

Locus of Action106

Photorecovery109

The＂Refractory＂Period109

Relationship with Some Other Effects113

Increase in Growth Rate in Cultures of Microorganisms116

In Summary117

9．INHERITED CHANGES119

Mutation Within the Nucleus121

Gene Mutation122

Chromosome Aberrations123

Polyploidy124

Crossing-Over124

Somatic Mutation124

Inheritance and Inherited Changes in Microorganisms125

Mutations126

Cytoplasmic Inheritance and Nucleocytoplasmic Relationships127

Killer Strains in Paramecium127

Bacterial Transformations127

Adaptation128

Differentiation130

Inheritance of the Tendency to Develop Cancer134

The Cancer Cell135

10．DEVELOPMENTAL GROWTH138

Some Studies of Regeneration143

11．ACUTE EFFECTS ON SKIN155

Penetration of Ultraviolet Light156

Sunburn of Human Skin160

Erythema161

Suntan165

Immunity to Sunburn166

Sunburn as an Inflammatory Response169

Hyperplasia169

Effects on Mouse Skin170

Effect of Visible Light179

In Summary180

PART Ⅲ．EXPERIMENTAL CARCINOGENESIS WITH ULTRAVIOLET LIGHT183

12．THE EXPERIMENTS185

Quantitative Measurements of Tumor Development186

Dosage and Development Time188

Dose-Rate Dependence194

Wavelength Dependence196

Effect of Temperature199

Tumor Types199

Photorecovery203

13．CELL PROLIFERATION AND THE GROWTH OF TUMOR MASSES205

14．QUANTITATIVE INTERPRETATION OF THE EXPERIMENTS216

Some Ideas That Do Not Fit216

Are There Separable Periods of Induction and Growth？216

Hypotheses Involving Somatic Mutation220

Constant Acceleration of Growth Rate223

An Approximate Model225

The Completed Model230

In Summary242

15．SOME JUSTIFICATIONS AND AN EXTRAPOLATION243

The Growth Curve243

Clone Populations251

Minor Effects253

An Extrapolation255

In Summary258

16．SOME SPECULATION ABOUT THE MECHANISM OF CARCINOGENESIS260

The Tem：A Hypothetical Particle260

Are the Tems Virus Particles？268

Is the Tem a Mutated Gene？270

Control of Tumor Growth271

The Question of Separable Stages in Cancerization272

Are Immediate Chemical Carcinogens Formed by Ultraviolet Light？274

Is the Tem a Common Denominator in Cancer？276

In Summary280

PART Ⅳ．SOME PRACTICAL CONSIDERATIONS283

17．SUNLIGHT AND CANCER OF THE SKIN OF MAN285

Skin Color and Cancer of the Skin288

Topographical Distribution of Skin Cancer in Man292

Distribution of Skin Cancer with Latitude295

Relative Incidence in Indoor and Outdoor Workers302

Other Diseases Caused by Light303

In Summary303

Prophylactic Considerations304

18．SOME PROBLEMS OF EVALUATION306

Accumulation of Effect of Environmental Carcinogens306

Cancer in the Individual309

Evaluation of Carcinogenic and Therapeutic Agents310

PART Ⅴ．ENVOI321

REFERENCES323

INDEX337