The Mitochondrial Free Radical Theory of Aging - Supernova: Pliki

Recommendations

Info

Conclusion: The Role of the Gerontologist Today Fig. 17.1. A Gompertz distribution, plotted in three different ways. Note that the tail in panel c is the same length whatever the population size. 197
198 The Mitochondrial Free Radical Theory of Aging The demographer may retort, in turn, that even very great medical advances will have only a small impact on maximum life span. The basis for such a belief is that, as simple mathematics easily reveals, the only way that we can substantially increase maximum lifespan is by increasing the MRDT. If the MRDT remains at around eight years, then a halving of overall mortality rates (that is, achievement of a situation in which people survive half of the diseases, accidents etc. of which they die today) would shift the graph of mortality to the right by only one MRDT—eight years. But, again, this logic rests on extrapolation: in this case, on the assertion that the MRDT will be as impervious to future medical advances as it has been to past ones. The mutually synergistic interactions between various degradative processes, described in Chapters 5 and 7, suggest exactly the reverse—that substantial retardation of any one of them, but particularly of mtDNA decline, would indeed stretch the MRDT. 17.2. Accidents, Diseases and Lifestyle Another reason why a great increase in lifespan may arrive sooner than is usually supposed is that people may hasten it by caution in everyday life. A number of studies have calculated a supposed upper bound on average human lifespan, by analysing how many people die of accidents and avoidable diseases and how many of “old age” (variously defined) and calculating an average lifespan if all death from the latter were removed. 4 I have never seen, however, a calculation of that sort which takes into account the prospect of changes in lifestyle that people might be expected to undertake in order to reduce their chances of dying of causes other than old age. It seems highly probable to me that a 50-year-old man (who wanted to live a long time) considering a parachute jump would be more circumspect about it if he were risking indefinitely many years of life than if, as now, he were only risking 30 or so. Activities that endanger the lives of others, such as driving, might very easily be outlawed. Once we begin to incorporate such factors, the numbers that come out of these calculations may be remarkably different. 17.3. An Operational Definition of the “Defeat” of Aging “Immortality” is a word so indescribably loaded with implications having nothing to do with my message that its use in this sentence is the only one you will find in this book. It is nevertheless necessary to consider, for sociological reasons if no others, where the practical boundary comes between increased lifespan and indefinite lifespan. It has been said that an indefinite lifespan is a theoretical impossibility, because there will always be some biological process, however slow, that will catch up with us in the end. This is logically incorrect, because “all” that is in fact needed is a steady stream of medical advances which, cumulatively, increases lifespan (for people of all ages) by a rate faster than the passage of time. If one doubts the plausibility that such a stream will happen, once begun, one should reflect that our understanding of the human body is rapidly—and not asymptotically—improving while the body itself is not getting more complex. I believe that in practice, therefore, what matters most from a sociological point of view is not whether (or when) large numbers of people are actually living much longer than now but when such a thing becomes perceived to be attainable. This perception will not necessarily even await the advent of effective human life-extension therapy. A single well-documented case of a treatment that doubled the longevity of mice, and which most specialists declare likely to work comparably well in humans too (as would probably be the case for both the approaches discussed here, in Chapters 14 and 15) would be quite sufficient, I believe, to trigger a drastic alteration of the public mood with regard to all life-threatening aspects of everyday life. This alteration would be hardly less great than if the announcement
Page 1 and 2:
COMPANY de Grey The Mitochondrial F
Page 3 and 4:
ISBN: 1-57059-564-X MOLECULAR BIOLO
Page 5 and 6:
7. The Status of Gerontological The
Page 7 and 8:
17. Conclusion: The Role of the Ger
Page 9 and 10:
I cannot overstate my profound grat
Page 11 and 12:
CHAPTER 1 Introduction 1.1. What Is
Page 13 and 14:
Introduction Some may feel that all
Page 15 and 16:
6 The Mitochondrial Free Radical Th
Page 17 and 18:
8 The Mitochondrial Free Radical Th
Page 19 and 20:
10 The Mitochondrial Free Radical T
Page 21 and 22:
Page 23 and 24:
Page 25 and 26:
Page 27 and 28:
18 Fig. 2.7. The respiratory chain.
Page 29 and 30:
Page 31 and 32:
Page 33 and 34:
24 Fig. 2.9. Types of protein impor
Page 35 and 36:
26 Fig. 2.10. Why the DNA bases pai
Page 37 and 38:
Page 39 and 40:
Page 41 and 42:
Page 43 and 44:
CHAPTER 3 An Introduction to Free R
Page 45 and 46:
An Introduction to Free Radicals Ta
Page 47 and 48:
Page 49 and 50:
Page 51 and 52:
An Introduction to Free Radicals Fi
Page 53 and 54:
An Introduction to Free Radicals Re
Page 55 and 56:
Page 57 and 58:
Page 59 and 60:
Page 61 and 62:
Page 63 and 64:
Page 65 and 66:
Page 67 and 68:
Page 69 and 70:
Page 71 and 72:
CHAPTER 6 History of the Mitochondr
Page 73 and 74:
History of the Mitochondrial Free R
Page 75 and 76:
Page 77 and 78:
Page 79 and 80:
Page 81 and 82:
Page 83 and 84:
Page 85 and 86:
Page 87 and 88:
Page 89 and 90:
Page 91 and 92:
CHAPTER 7 The Status of Gerontologi
Page 93 and 94:
The Status of Gerontological Theory
Page 95 and 96:
The Status of Gerontological Theory
Page 97 and 98:
CHAPTER 8 The Search for How Mutant
Page 99 and 100:
The Search for How Mutant mtDNA is
Page 101 and 102:
Page 103 and 104:
Page 105 and 106:
Page 107 and 108:
CHAPTER 9 The Search for How So Few
Page 109 and 110:
The Search for How So Few Anaerobic
Page 111 and 112:
Page 113 and 114:
Page 115 and 116:
Page 117 and 118:
Page 119 and 120:
Page 121 and 122:
CHAPTER 10 Frequently-Asked Questio
Page 123 and 124:
Frequently-Asked Questions The effe
Page 125 and 126:
Frequently-Asked Questions Table 10
Page 127 and 128:
Frequently-Asked Questions through
Page 129 and 130:
Frequently-Asked Questions has been
Page 131 and 132:
Frequently-Asked Questions SOS, sin
Page 133 and 134:
Frequently-Asked Questions for almo
Page 135 and 136:
Frequently-Asked Questions Fig. 10.
Page 137 and 138:
Frequently-Asked Questions Fig. 10.
Page 139 and 140:
Frequently-Asked Questions of elect
Page 141 and 142:
Frequently-Asked Questions Referenc
Page 143 and 144:
Frequently-Asked Questions 45. Clay
Page 145 and 146:
CHAPTER 11 A Challenge from Textboo
Page 147 and 148:
A Challenge from Textbook Bioenerge
Page 149 and 150: A Challenge from Textbook Bioenerge
Page 165 and 166: 160 The Mitochondrial Free Radical
Page 177 and 178: CHAPTER 14 Ablation of Anaerobic Ce
Page 179 and 180: Ablation of Anaerobic Cells: Techni
Page 181 and 182: CHAPTER 15 Transgenic Copies of mtD
Page 183 and 184: Transgenic Copies of mtDNA: Techniq
Page 193 and 194: CHAPTER 16 Prospective Impact on th
Page 195 and 196: Prospective Impact on the Healthy H
Page 197 and 198: Prospective Impact on the Healthy H
Page 199: 196 The Mitochondrial Free Radical
Page 203 and 204: Index Symbols “~”, 19 A Acetald
Page 205 and 206: Index Copper 35, 107 see also trans
Page 207 and 208: Index Heart comparison to man-made
Page 209 and 210: Index genetic code 23, 115-118, 177
Page 211 and 212: Index Perhydroxyl radical 41, 122,
Page 213 and 214: Index protonation see protonation (
Page 215: MOLECULAR BIOLOGY INTELLIGENCE UNIT
show all

The Mitochondrial Free Radical Theory of Aging - Supernova: Pliki

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?