Biochemistry of the Eye

by Whikehart

• ISBN13: 9780750671521
• ISBN10: 0750671521
• Edition: 2nd
• Format: Paperback
• Copyright: 2003-08-22
• Publisher: Butterworth-Heinemann

Summary

This specialized text presents a review of general biochemistry and an in-depth exploration of biochemistry unique to the eye. As a readable introduction to this challenging topic, it describes the molecular structures and biochemical events that occur in the eye. Specific clinical examples link basic science to clinical practice and provide a concrete basis for understanding complex concepts. This edition includes new, updated information in revised chapters plus two additional chapters on ocular fluids and pathology. General biochemistry is discussed in each chapter, with examples of biochemical pathology and disease processes such as age-related cataract formation and ocular diabetes. Well-illustrated content, featuring color inserts with 10 illustrations, shows visual aspects of biochemistry. Each chapter features a general review of the subject matter prior to discussing ocular biochemistry. Discussions of proteins that are either unique to the eye and/or have special functions in the eye, such as collagen's role in the structure of the cornea, emphasize the importance of these compounds and their many essential cellular and ocular functions. Discussions of the nature and function of enzymes, in addition to descriptions of examples of specific enzymes found in the eye, highlight the manner in which many biochemical reactions occur in the eye is via enzyme catalysis. A chapter on carbohydrates emphasizes the importance of the two roles of carbohydrates in ocular tissue: energy supply (nutrition) and as a source of extracellular structure. An explanation of the many different kinds of lipids that exist in the eye features the most up-to-date material on tear film lipids and useful information on dietary Vitamin A requirements. A chapter on hormones deals with the role of hormones in general and shows how hormones play roles in ocular functions, including the process of visual transduction as a hormonal function. A thorough review of nucleic acid chemistry points out its role in molecular biological functions such as DNA replication, RNA transcription, and protein translation, as well as DNA mutations. A chapter on neurochemistry provides an understanding of basic neurochemistry and how neurochemistry can explain the complex functions of the retina. The immunochemistry chapter contains basic material on biochemical and cellular immunology, discussing immune privilege in the eye and the importance of immune reactions at the anterior segment. A new chapter describes the biochemical pathology of four degenerative conditions (corneal ulcers, chemical burns, glaucoma, and cellular apoptosis) to help the clinician understand pathological processes and the time course of degenerative processes and methods of treatment. A new chapter on Water and Ocular Fluids offers unique coverage of the functions of eye fluids and how drug companies must design drugs for the ocular surface, comparing the physical, chemical, and biological properties of water with fluids found in the eye.

Author Biography

David R. Whikehart, Ph.D.: Professor, Vision Science Research Center, School of Optometry, The University of Alabama at Birmingham

Table of Contents

Four-Color Section	p. xv
Water and Ocular Fluids: Physical Chemistry of Ocular Fluids	p. 1
Water	p. 1
Hydrogen Bonds	p. 3
Weak Electrolytes and Buffers in Water	p. 3
The Henderson-Hasselbalch Equation	p. 5
Biological Buffers in Ocular and Other Body Fluids and Tissues	p. 6
Ocular Fluids	p. 7
Blood in the Ocular Globe	p. 7
Aqueous Fluid	p. 9
The Vitreous (Vitreous Body)	p. 10
Precorneal Tears	p. 11
Summary	p. 12
Problems	p. 13
Proteins: Essential Components of the Eye	p. 15
Crystallins	p. 22
Characteristics	p. 22
The Aging Process and Effects on Crystallins	p. 27
Cataract Formation	p. 28
Rhodopsin and Cone Pigment Proteins	p. 33
Mucous Glycoproteins	p. 40
Collagen	p. 41
Ocular, Structural Roles	p. 45
Summary	p. 50
Problems	p. 51
Enzymes: Ocular Catalysts	p. 55
Michaelis-Menten Enzymes	p. 56
Allosteric Enzymes	p. 60
Enzyme Inhibation	p. 62
Lysozyme	p. 64
Na, K-ATPase	p. 68
Lactate Dehydrogenase	p. 70
Aldose Reductase	p. 75
Matrix Metalloproteinases	p. 77
Summary	p. 81
Problems	p. 82
Carbohydrates	p. 85
Energy Metabolism	p. 89
Glycolysis	p. 92
The Anaerobic Exit of Glycolysis	p. 95
The Aerobic Exit of Glycolysis	p. 97
Glycogen Formation and Degradation	p. 102
The Pentose Shunt	p. 103
Other Aspects of Carbohydrate Metabolism	p. 105
Ocular Comparative Metabolism	p. 106
Problems of Carbohydrate Transport and Metabolism: Diabetes and Galactosemia	p. 108
Glucose Transport Into Cells and Its Relationship to Diabetes	p. 109
Type 1 Diabetes	p. 110
Type 2 Diabetes	p. 115
Ocular Pathological Effects Produced by Diabetes	p. 117
Introduction to Galactosemia	p. 122
Ocular Effects of Galactosemia	p. 123
Structural Carbohydrates	p. 123
Sugar Oligomers and Polymers	p. 123
Summary	p. 128
Problems	p. 129
Lipids	p. 133
Lipid Classcifications	p. 133
Fatty Acids	p. 133
Triacylglycerols	p. 134
Phospholipids	p. 136
Isoprenoids	p. 138
Esters	p. 139
Eicosanoids	p. 139
Glycolipids	p. 140
Cell Membranes	p. 142
Lipid Components	p. 142
Protein Components	p. 144
Carbohydrate Components	p. 144
Membrane Component Summary	p. 145
Transport: An Essential Membrane Function	p. 145
Precorneal Tear Film Lipids	p. 147
Lipids of the Retina	p. 149
Vitamin A	p. 150
Glycolopid Storage Diseases and Vision	p. 153
Summary	p. 154
Problems	p. 155
Hormones	p. 159
Hormone General Functions: Chemical Micromanagers	p. 159
The Endocrine System (Neuroendocrine System)	p. 161
Hormone Effects, "Shelf Life," and Concentrations	p. 162
Hormones: Chemical Classes	p. 163
Plasma Membrane Hormones and Their Receptors: Mechanisms	p. 165
Cyclic Nucleotide Mechanisms	p. 165
Inositol Trisphosphate/Ca[superscript +2] Mechanisms	p. 169
Nitric Oxide	p. 171
Light Transduction: A cGMP Mechanism	p. 171
Graves' Disease: Autoimmune Mischief with Thyroid Hormones	p. 176
DNA Binding Hormones: Mechanism	p. 179
Paracrine Hormones	p. 182
Summary	p. 185
Problems	p. 186
Nucleic Acids	p. 191
Nucleic Acid Biochemistry	p. 191
Deoxyribonucleic Acid	p. 191
DNA Replication	p. 195
Ribonucleic Acid	p. 198
Transcription of RNA	p. 199
The Genetic Code and "Nonsense" Sequences	p. 200
The Formation of Messenger RNA	p. 202
Protein Synthesis (Translation)	p. 202
Mutations to DNA and to Nucleic Acid Processing	p. 210
Molecular Biology of the Crystallins	p. 213
Normal Crystallins	p. 213
Crystallin and Other Protein Genetic Defects	p. 218
Viral Intervention in the Cornea	p. 220
Potential Gene Therapy of Rentinal Disease	p. 223
Summary	p. 225
Problems	p. 226
Ocular Neurochemistry	p. 231
Neurotransmitters and Receptor Proteins and Their Properties (Including Ocular Autonomic Functions)	p. 234
Neurochemistry of the Retina	p. 239
Ocular Neurochemical Pathology	p. 245
Summary	p. 246
Problems	p. 247
Ocular Immunochemistry	p. 249
Review of Immunoglobulins	p. 249
Ocular Immunoglobulins	p. 256
Complement	p. 257
Complement of the Eye	p. 260
Inflammation	p. 260
Ocular Inflammation	p. 266
Summary	p. 267
Problems	p. 267
Ocular Biochemical Degradation: Aging and Pathological Processes	p. 271
Cellular Apoptosis	p. 271
Apoptosis in Ocular Cells	p. 273
Liquefaction of the Vitreous	p. 275
Important Vitreal Gel Components	p. 275
Molecular Aging Effects and Liquefaction	p. 277
Chemical Burns of the Cornea	p. 277
Early Chemical Damage	p. 278
Immunochemical Damage	p. 278
Summary	p. 279
Problems	p. 280
Glossary	p. 283
Answers to Problems	p. 306
Index	p. 313
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