A JOURNAL FOR AND ABOUT OLDER PEOPLE
OCTOBER 1946
THE DAWN OF GERONTOLOGY
Frank Hinman
THE EFFECT OF AGING ON THE COURSE AND OUTCOM Louis M. Hellman
THE EFFECT OF COFFEE, HUMAN DIETS, AND INHERI UPON
THE LIFE SPAN e IN
Gladys A. Sperling, J. K. owed 1860 1880 1900 1920 1940 1960 1980
THE SIZE OF SOMATIC CH THE RAT
= J. Bies
G AGING
CHEMICAL CHANGES IN THE as
THE EFFECT
THE SURVIVAL TIME OF MICE Thomas S. Gardner and Francis B. Forbes
CHARACTERISTICS OF COMPULSORY HEALTH INSURANCE Elizabeth W. Wilson
THE BIBLE AND OLD AGE John J. Griffin
NANCY Cay MICE \ ¥ CID ON ; |
EDITORIAL STAFF GERONTOLOGICAL SOCIETY, INC.
COMMITTEE ON PUBLICATIONS
Roy G. Hoskins, Chairman Boston
LAWRENCE K. FRANK WILLIAM DEB. MACNIDER Epwarp J. Strecuitz New York Cuaret Hitt WASHINGTON
EDITORS Rosert A. Moore, Editor-in-Chief Rita Noag, Assistant to the Editor
Correspondent for Great Britain Correspondent for South America V. KorencHEvsky, OXFORD B. A. Houssay, BuEnos Aires
Correspondent for France R. CourrizR
CONSULTANTS TO THE EDITOR
Howarp W. BLAKESLEE Davw Dretz Associated Press Scripps-Howard Newspapers
F. L. CAMPBELL WALDEMAR KAEMPFFERT Scientific Monthly New York Times
Watson Davis Rosert D. Porrer Science Service American Weekly
JANE STAFFORD Science Service
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Journal of Gerontology
Volume 1 October, 1946 Number 4, Part 2
The Dawn of Gerontology FRANK HINMAN
H' LOOKED it when he said, more to himself than to any one in particular, as he took his seat for lunch, “I’m through, I’m finished,” adding in answer to questioning glances, “I have retired.” A man of 65 with nothing wrong physically faced a future of many years for which he had made no plans. Over night the executive posi- tion to which he had worked up had slipped out of his hands for no other reason than his age. What would he do?
Elders at present find few opportunities in industry. Professional men are about the only ones who can ease off in later years. It is odd but true that those whose job has been manual make the adjustment of retirement more smoothly than those whose work has been mental. The day laborer can keep busy with his puttering and gardening, but to most white collar pensioners this would be deadly and lead almost certainly to some physical or mental disaster. Every healthy elder needs an outlet in order to round out a full, contented life, and this outlet not only must be of interest but must at least appear to be worthwhile.
Why the present concern? it may be asked. Haven’t people always retired when they got too feeble or too old? Of course, but the sig-
Dr. Frank Hinman received his A.B. degree from Stanford University in 1902 and his M.D. degree from Johns Hopkins in 1906. He has been clinical professor of urology at the University of California since 1915. He is chief of the urology service at the University of California Hospital and on the staff of the Franklin Hospital and the San Francisco Hospital. He has-won honors at science exhibi- tions of the American Medical Association, is a past president of the American Association of Genito-Urinary Surgeons, and is a fellow of the American College of Surgeons. Dr. Hinman is the author of a widely used textbook of urology.
Words in italics are defined in the Glossary, page 231. *189°
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190 JOURNAL OF GERONTOLOGY
nificance of retirement has been changed completely by the over- whelming increase in the number of people who now reach the age of retirement.
At the beginning of the seventeenth century the population of the world was estimated at 445,000,000. In 1937, the estimate was close to 2,104,000,000. The population of the United States, largely be- cause of immigration, doubled every twenty-five years during the nineteenth century, but with a diminishing birth rate and restricted immigration, there has been an increase of a bare 7 per cent in the last decade. Assuming no immigration, a decline in the birth rate, and an increase in longevity, one expert computes “a maximum of nearly 154,000,000 in 1985 or thereabouts, after which it will begin to de- cline .. . and by the end of the century our numbers will be little, if any, greater than in 1920.” It would seem, therefore, that the population of this country soon will become stationary at somewhere between 100 and 150 million people.
Today every child born in this country has an expectancy of more than 64 years, and when the maximum of population is reached in 1985 or thereabouts, the average lease on life probably will be over 70 years. From 1930 to 1940 the population increased 7.2 per cent, but the proportion of people over 65 increased 35 per cent in the same decade—almost five times the general increase. By the turn of the century, so population experts say, 32 per cent of the population will be elders over 54, and only 23 per cent, youth under 20. Instead of a median age of around 30 as at present while youth still outnumbers the aged two to one, the median age fifty-five years hence will be close to 50 and youth will be far outnumbered. The United States will then be truly a country of elders.
Almost every one nowadays is biologically minded enough to be- lieve that man is an animal descended from lower forms of life through the natural laws of evolution. Only a few persons, however, will admit that these laws are still in force and apply to man’s social and human functions as well as to his biologic function as an animal in the past. What makes man differ from other animals is his code of human values, which values have struggled through the changes of past history and now face the struggle of existence through the muta- tions and selections of the future. However, future changes in human values need not be left to chance as were the physical changes in
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biology, because man himself and not nature is their trustee. The United Nations Organization by its promise of mutual satisfactions is a product of evolution in human values and faces the struggle of survival.
The care of the sick, the helpless, the needy, and the insane has long been recognized as purely human. For the sake of humanity, man has shouldered a tremendous burden of social obligations, and as yet he is barely conscious of these new qualities which make him human. By nature he is not altruistic, and he will become so only if the changes and survivals of human values choose this route.
What gives these human values, which are still in the first stage of evolution, such a tremendous significance at this time is the current scientific revolution coming as it does immediately after the mechani- cal revolution. Mechanical and scientific technology permits these human values to go in the face of all the rules of biologic evolution. Man has defied nature’s law of survival of the fittest and has cared for and preserved the weak as well as the strong. Obstetrics and pediatrics have lowered infant mortality to a minimum. Medicine and surgery are eliminating one after the other the dangers of death from disease during adulthood, so that the day is near when every child born will expect to die of old age. Thus humanity has preserved and nourished the moron, the feeble-minded, the insane, and the criminal, and has allowed their intermarriage and reproduction until now the mass of human intelligence is being lowered instead of raised.
However, the hope of Homo sapiens to survive his outlawry of na- ture lies in his reason and his brain. Fortunately also no other species has ever shown such remarkable adaptability to environment.
Every species has an optimum period of life. Some one has estim- ated this as six times the growth period. This rule would make the optimum period for man from 120 to 150 years of age, since tone growth is not finished before the twentieth to the twenty-fifth year. At the present time few men pass 100 even with the help of medicine, but with a cure for cancer, for hardening of the arteries, and for or- ganic heart disease, all of which are reasonably possible, the medical profession will keep more and more people alive longer and longer. Imagine a nation such as the United States with a stationary popula- tion of 100 million people, the majority of whom reach 120 to 150 years of age—or even the soon-to-be-assured 70?
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However, senescence does not necessarily mean a helpless decline and degeneration. The physical activity of an individual may reach the peak at around 40 years, but mental ability, the capacity for in- tellectual work from which are derived those human values which make men different from animals, is better at 60 than at 30 and de- clines only slowly afterwards. This fast growing surplus of intellectual power may be the evolutionary process which will save the race from early extinction. At present nothing is being done either to use effec- tively or to improve the intellect and mature judgment of elders. Euthenics so far has been confined solely to improving the environ- ment of youth. The recent increase in the number of old people creates the need for a well planned old age movement also.
The social status of elders at present is not satisfactory. On the farm, Grandpa would keep busy and useful, but not in the city, and there has been a tremendous shift from rural to urban life. The at- titude towards old age has changed too. Age is not revered as formerly but is just more or less tolerated. In consequence almost everybody dreads the thought of growing old. The idea of the dependence of the aged is spreading and society even contemplates giving everyone over 55 or 60 a pension for life. When medicine keeps people alive for another sixty or more years, what a mob of dependents there will be then. Social security of the pension kind is not at all the answer. No idle person ever was content. Throughout life man must be active or be bored. Activity can be manual or mental, but any social security with no outlet for muscle or brain is unbiologic. The significance of leisure in old age is the opportunity of renewed activity, not the prospect of going from one rocking chair to another. Society must popularize this idea, furnish the opportunities for activity, and benefit by the results. Every individual of the future must begin at 40 to prepare himseli for the inevitable period of senescence. Then when he has to let down or is forced to retire, he will have hobbies or other interests to fall back on, from which will come some opportunity for action and usefulness.
Heretofore, people have grown old without a thought of how to grow old, but now that aging deprives so many people of their past usefulness, the process needs scientific study. Gerontology, as this study is called, covers normal and pathologic conditions of aging. The pathologic conditions, or the diseases of old age, are covered by
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THE DAWN OF GERONTOLOGY 193
geriatrics, a branch of medicine. But the aging process of healthy people is a much more important problem, demanding study of the social aspects, industrial adjustments, and educational needs of normal older people. There has been practically no scientific research in gerontology. Now the time has come for an intensive study of the biologic processes of aging and the interrelation of these processes with changing social conditions.
Elders need to be classified as to abilities and disabilities. Many of the disabled may be moved into the active group through the aid of geriatrics, already a fast growing specialty. Tests to determine the particular aptitudes of the able elders can be developed. Social wel- fare clinics to advise and encourage the aged can be established. Op- portunities for work, study, and play can be provided. Of first im- portance in a movement to make old age worthwhile is the develop- ment of schools or departments of gerontology which will institute the necessary research, will spread the philosophy that each in- dividual should plan an active self reliance in old age, and will provide a scholastic program to meet the requirements. A school for elders is not too absurd. The majority are capable of being taught, and an active interest in a curriculum would not only make for happiness but would salvage ideas and intellect at a time when society needs them most.
Instead of thinking “I’m through, I’m finished” upon retirement at 65 from whatever regular job a man has held, how much better were he to feel: ‘“My life has just begun.”
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The Effect of Aging on the Course and Outcome
of Pregnancy
Louis M. HELLMAN
HE matter of childbearing at either end of the normal reproduc-
tive period in a woman’s life has attracted the attention and imagination of physician and layman alike. Down through the ages fabulous stories of children born to the very young and the very old recur with surprising regularity. The best known of these is the story of Sarah of the Old Testament, who, at 94 and long after the cessation of her menstrual periods, not only bore Abraham a son but was able to nurse this child. While it is impossible to say definitely that these reports are not true, it is worth noting that most of the instances of children being born to extremely old mothers occurred before the present century and at a time when the recording of births was un- reliable. In the experience of the Johns Hopkins Hospital, covering approximately 50,000 births, the greatest authenticated maternal age is 48.
Regardless of the greatest age at which a woman has given birth, the age of the mother does have an important effect on the course and outcome of her pregnancy. Obstetricians have rather arbitrarily taken the age of 35 years as the end of youth and the beginning of old age as far as human reproduction is concerned. Particularly is this so in the case of the primiparous woman, who is termed elderly at 35.
Dr. Louis M. Hellman received his \.B. degree from Yale in 1930 and his M.D. degree from Johns Hopkins in 1934. He served at the New York Hospital, the Boston Lying-In Hospital, and at Johns Hopkins. He has just returned from three years’ service in both Atlantic and Pacific with the Navy, during most of which time he was stationed on the hospital ship Refuge. He is now associate professor of obstetrics at Johns Hopkins. His chief fields of interest are obstetri- cal pathology, hemorrhagic disease of the newborn, and obstetrical anesthesia.
Words in italics are defined in the Glossary, page 231. *194-
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EFFECT OF AGING ON PREGNANCY 195
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Much has been written concerning the peril both to her and to her child when pregnancy occurs at or beyond this age.
The risks lie in the increased maternal and infant mortality rates and also in the medical complications of middle age, such as heart and kidney disease and diabetes, and the pregnancy complications of toxemia and myomata.
The rate for stillbirths and neonatal deaths, regardless of the age of the mother, in a series of 45,000 deliveries, was 57.7 per thousand deliveries for the first-born child. The rate was 71.8 when the mother was between 35 and 39, and 80 per thousand births when the mother was between 40 and 45. There is also the factor of increased incidence of premature births and an increased vulnerability of these pre- maturely born infants correlated with the age of the mother. The death rate of premature children is between ten and twenty times that of term infants.
In general it has been the policy of the Johns Hopkins clinic to allow older patients to deliver normally if the course of the pregnancy has been normal and the delivery promises to be so. It has not been found that the labor of older primiparous women is longer or more difficult than that of younger women. However, the slightest devia- tion from normal, be it toxemia, myomata, faulty position of the fetus in the uterus, or uterine inertia, deserves special consideration and frequently merits cesarean section. The clinic average for ab- dominal delivery is 4 per cent; however the average for the age group 35 to 39 is 16 per cent, and for the 40 to 45 group, 44 per cent. While cesarean section does not necessarily mean increased maternal mortality, there is a definite infant wastage rate, and hence excellent obstetrical judgment is required to balance the risks and make the wise decision.
In the case of the multiparous woman, while the pressure on the obstetrician to secure a good baby at all costs is somewhat reduced, the age factor is still present, and there is, in addition, the disad- vantageous effect the woman’s previous deliveries have had upon her general condition. The stillbirth and neonatal mortality rates of women with eight or more children are nearly two and a half times that of the low rates for second and third babies, and the maternal
mortality rate jumps three and a half times after the birth of the
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eighth child. The birth of many children relaxes the abdominal wall and the uterus, and there are many more cases of abnormal position of the fetus and hemorrhage occurring after delivery, as well as pre- mature separation of the placenta. To reduce these hazards to the older patient, the Johns Hopkins clinic offers to women with eight full term pregnancies either contraceptive advice or sterilization.
There is one additional factor which needs to be considered in a discussion of the effect of aging on pregnancy. This is the diminution of reproductive vigor as maternal age advances. There is an increase not only in fetal deaths, as has been shown, but also a higher in- cidence of fetal abnormalities and certain congenital diseases. The increased occurrence of these conditions begins shortly after 30 years. The mongoloid infant, for example, is born usually to older mothers, the peak being reached at 41 years. The incidence of dwarfism likewise rises with advancing maternal age.
Thus it is clear that maternal age exercises a strong influence on the course and outcome of pregnancy. The hazards discussed do not imply that it would be well to stop all childbearing in the older age group. They should, however, serve as warning posts to obstetrician and mother alike that there are dangers to be watched for, and that additional care must be taken. They should serve also to show the young married woman that her greatest talisman in pregnancy is youth, and that the formation of her family should not be too long delayed.
To be 70 years young is sometimes far more cheerful and hopeful than to be 40 years old.
OLIVER WENDELL HOLMES
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The Effect of Coffee, Human Diets, and Inheritance Upon the Life Span of Rats
A. SPERLING, J. K. L. L. BARNEs, AND CLIVE M. McCay
BACKGROUND
HE study of nutrition has made great advances in recent years as scientists have learned what a healthful diet should include. Moreover, the discovery of the exact composition of natural vitamins and their synthetic production, the manufacture of calcium pills and iron extract and so on have made it possible to add to any diet many of the things essential to health which the diet may lack. Thus such
Gladys A. Sperling has been in charge of the Small Animal Colony in the Animal Nutrition Department at Cornell University since 1936. She received her A.B. degree from Oberlin College in 1927, with a major in chemistry, and an M.S. in bacteriology from Cornell University in 1936.
Dr. John K. Loosli was assistant professor of animal nutrition at Cornell University from 1939 till early 1946. He is now full professor. He is also attached to the Fish and Wildlife Service of the Department of the Interior. He received his B.S. in 1931 from Utah State College, his M.S. from Colorado College in 1932, and his Ph.D. from Cornell in 1938.
Dr. LeRoy L. Barnes is associate professor of biophysics at Cornell Uni- versity. He received his A.B. degree at Oberlin in 1926 and his Ph.D. from Cornell in 1932.
Dr. Clive M. McCay has been professor of nutrition at Cornell University since 1934. He received his A.B. degree from the University of Illinois in 1920, his M.S., from Iowa State College in 1923, and his Ph.D. from the University of California in 1925. He has taught at the University of Texas, Iowa State College, the Uni- versity of California, and Yale.
The studies reported on in this paper were carried out with the aid of grants by the Federal Government, the State of New York, and the Rockefeller Founda- tion. Expert technical assistance was rendered by Mrs. Vonda McCloskey, Mrs. Ruth Seither, and Mr. Alfred Armitage. ;
The sources of the vitamin supplements used were ““Napco XX” and “Vitab,” made by the National Oils Products Co., Harrison, N. J.
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198 JOURNAL OF GERONTOLOGY
deficiency diseases as pellagra and scurvy may be eliminated.
The full potentialities of the study of nutrition, however, have not yet been explored. Does the diet affect the graying of the hair? Can the diet be managed so as to prolong life?
Since it is difficult to carry out extensive dietary experiments on human beings, scientists use the laboratory animal most nearly like a human being in nutritional habits—the white rat. The average life span of this animal is two years, and so several generations can be studied during the working life of a man. .
Now FOR THE INVESTIGATION OF Miss SPERLING, Dr. Loos, Dr. BARNES AND Dr. McCay
The purpose of this study was to determine the effect upon the longevity in the rat, of “improving”’ a diet similar to that consumed by many persons in the United States.
One group of rats (A) was fed this average diet, including eggs, milk, fats, hamburger and pork sausage, sugar, unenriched white bread, and some fruit and vegetables.
A second group (B) was fed this same diet except that included were twice as much milk, meat richer in vitamins, more vegetables including leafy vegetables, and less sugar and potatoes.
A third group (C) was given the same diet as the A group except that vitamins were added.
In order to make this experiment accord further with human practices, coffee was fed to half of each dietary group.
Although group A grew more slowly than groups B and C, all three groups lived about the same length of time. Life sran, of course, is only one test of an optimum diet, but judging from _. = life span alone the diet was not improved by the addition of vitamins and calcium.
Furthermore, there was no evidence that coffee shortened the life span of any group. Because so many claims have been made that coffee has bad effects on men and animals, a second series of experi- ments was made. Coffee was given as the only liquid to some rats, water to others. All but one female (on water) produced at least one litter during the first year. The growth of the young from mothers fed strong coffee was slightly less, but differences disappeared as the rats matured. This second generation of rats was raised upon a similar diet and beverages. These rats in turn were used to produce a third
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EFFECT OF HUMAN DIETS UPON LIFE SPAN OF RATS 199
generation. No differences resulted. No evidence was found that coffee modified growth or reproduction.
However, inheritance seemed to play an important role in deter- mining the life span of the rat. Of 19 rats from short-lived litters, 14 died early deaths, 4 lived an average life span, and only 1 lived longer than average. Of 58 rats from long-lived litters, 44 were long-lived, while only 8 died prematurely and six lived an average life.
Socrates: There is nothing which for my part I like better, Cephalus, than conversing with aged men; for I regard them as travelers who have gone a journey which I too may have to go, and of whom I ought to inquire whether the way is smooth and easy or rugged and difficult. And this is a question which I should like to ask of you, who have arrived at that time which the poets call “the threshold of old age’’: Is life harder toward the end, or what report do you give of it?
Cephalus: The truth is, Socrates, that these regrets [of old people], and also the complaints about relations [that they do not care], are to be attributed to the same cause, which is not old age, but men’s char- acters and tempers; for he who is of a calm and happy nature will hardly feel the pressure of age, but to him who is of an opposite disposition
youth and age are equally a burden. Plato’s Republic
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The Size of Somatic Chromo- somes at Different Ages in the Rat
Joun J. BIESELE
BACKGROUND
T Is common knowledge that individuals related to each other by
descent resemble each other to a greater or less degree, but that no two are identically alike (except in the extremely rare case of identical twins). For centuries man has utilized this knowledge, more or less unconsciously, in the breeding of animals and plants, without know- ing why “like begets like.” Today one of the newest of the sciences, known as genetics, is endeavoring to explain the whys and wherefors of the similarities and differences between related individuals.
In higher organisms, including man, the individual is originally a single cell, formed by the union of egg and sperm, and this one cell contains the factors which will determine all of the inherited charac- teristics of the individual. The cell is made up of jelly-like material, known as cytoplasm, and a nucleus. In the nucleus are rod-like chromosomes, made up of the all-important genes, which determine
Dr. John J. Biesele received his A.B. and Ph.D. degrees from the University of Texas, in 1939 and 1942 respectively. From 1942 to 1944 he was a Fellow of the International Cancer Research Foundation, working at the University of Texas, the Barnard Free Skin and Cancer Hospital in St. Louis, and the University of Pennsylvania. From 1944 to 1946 he was research associate in the department of genetics of the Carnegie Institution of Washington. At present he is assistant to the Sloan-Kettering Institute for Cancer Research in New York City, and a research associate in the department of biology at the Massachusetts Institute of Technology. His work has been chiefly with chromosomes and nuclear cytol- ogy, and histochemistry.
This work is part of a general study on aging organized by Dr. E. J. Farris of the Wistar Institute of Anatomy and Biology, with the aid of cooperating scientists and with the support of the Samuel S. Fels Fund. The author began the study at the Department of Zoology of the University of Pennsylvania.
Words in italics are defined in the Glossary, page 231. 200°
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THE SIZE OF SOMATIC CHROMOSOMES 201
the characteristics of the individual-to-be. The chromosomes can be seen through a microscope, the genes cannot; but like the unseen atoms, their existence is entirely real.
The somatic chromosomes are those in the cells of the body, which cease to exist when the body dies. In contrast there are the chromo- somes of the sex cells, which determine the heredity of every in- dividual and are passed on from generation to generation. Chromo- somes are paired. In man there are twenty-four pairs. One of the pair may be responsible for blue eyes, the other, for brown. At the time of maturation of the sex cell, one of each pair of chromosomes splits off, and ovum and sperm each contain but half the usual number of chromosomes. When ovum and sperm are united, however, the usual number of chromosomes is restored. Certain characteristics trans- mitted by the chromosomes are known as dominant characteristics, others are known as recessive. Brown eyes, for example, dominate over the recessive blue. Thus if a chromosome transmitting the characteristic of brown eyes is handed down from either parent, the child will have brown eyes regardless of the chromosome from the other parent.
Dr. Biesele has done a good deal of work with chromosomes. He has studied the size of chromosomes in rats in relation to the B vitamins. He has studied the enlargement of chromosomes in certain varieties of cancer. In this paper he presents his findings in regard to the size of chromosomes at different ages in the rat, to learn more about the function of chromosomes in the life of the cell as it passes from em- bryonic life to old age.
Now FOR THE INVESTIGATION OF DR. BIESELE
Material was obtained from 44 albino rats, killed at ages ranging from the late embryo stage to more than 1,000 days. (A rat is be- ginning to be old at 600 days.) The following organs of the body were studied: liver, kidney, epidermis, lung, small intestine epithelium, mesenteric lymph node, spleen, thymus, and adrenal.
The maximum width and average length of the chromosomes in the cells of these organs were measured by means of a millimeter ruler, and from these measurements the average chromosome volume was calculated. Within the same animal there were often significant differences between the average chromosome volumes from one organ
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202 JOURNAL OF GERONTOLOGY
or tissue to another, but the variations in chromosome size in a given tissue of different animals of the same age group were not significant.
However there were important variations in chromosome size be- tween age groups. The overall variability was least in the embryonic or newborn animals, most extensive in the oldest animals. Each tissue followed a more or less individual pattern of changes in chromosome size with age. Roughly, there were three sets of patterns.
First were those patterns exhibiting considerable uniformity throughout life, such as was seen in the epidermis (see figure) and the lung. The second set of patterns involved an increase in size of
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Variation of average chromosome volume with age in epidermis. The vertical bars represent range of average volumes per metaphase in each group, the longer horizontal bars connected by dash lines represent the group means, and the shorter horizontal bars mark off one standard deviation on each side of the mean.
chromosomes near birth and a decrease in later stages—as in the epithelium of the small intestine, the mesenteric lymph node, and the spleen. In the third set of patterns, the chromosomes increased in size and remained at this high level. The kidney and perhaps the liver might be included in this group.
INTERPRETATION
As yet it is not known where this piece of information fits into the picture of aging. As time goes on, other scientific research will con- tribute other pieces of information, seemingly unrelated perhaps, until one day all the pieces have been furnished and, like a jigsaw puzzle, are assembled into a final picture.
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Some Chemical Changes in the Human Thoracic Aorta Accompanying the Aging Process
Victor C. MYERS AND WALTER W. LANG
BACKGROUND
I HAS been assumed on the basis of microscopic examination of blood vessels that the aging process is associated with certain changes in the makeup of the vessel walls. In between an outer coat, called the adventitia, and an inner lining, called the intima, the walls of blood vessels are composed of elastic fibers (made up chiefly of elastin), connective tissue (made up chiefly of collagen), and muscle. This middle layer is designated as the muscularis. The elastic fibers are strong and flexible, while the connective tissue is soft and spongy.
The function of a blood vessel depends in large part on the mus- cularis. As the heart beats, blood is forced into the arteries. They become much larger and the walls are stretched. Between beats of the heart the elastic wall recoils and the contained blood is forced onward.
Dr. Victor C. Myers has been professor of biochemistry at Western Reserve University since 1927. He received his B.A. degree from Wesieyan University in 1905, an M.A. in 1907, and an honorary D.Sc. in 1930. He was university fellow at Yale, receiving his Ph.D. there in 1909. Previous to going to Cleveland, he held professorships in biochemistry at the Albany Medical College, the New York Postgraduate Medical School, and the State University of Iowa. His chief field of study is clinical biochemistry.
Mr. Walter W. Lang received his B.S. degree in 1938 from Kent State Uni- versity, Ohio. He was a high school instructor in chemistry until 1941, when he went to Western Reserve University School of Medicine, Cleveland, as a teaching fellow in biochemistry, and received the M.S. degree in biochemistry from the Graduate School in 1943. The data presented are taken from his master’s thesis. He then entered the Georgetown University Medical School where he will re- ceive the M.D. degree in 1947.
The work on this paper was done at the department of biochemistry of the School of Medicine, Western Reserve University, in Cleveland, Ohio.
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204 JOURNAL OF GERONTOLOGY
Thus the pump-like action of the heart is changed to a more even flow in the smaller vessels. Any loss of elastic tissue would decrease this function of the arteries.
From microscopic study of blood vessels, it seems that the elastic fibers, or elastin, decrease with age, while the less sturdy connective tissue (collagen) increases. To prove this assumption, however, it is necessary to make chemical analyses of the walls of blood vessels, since elastin, collagen, and muscle are different in their chemical composition. Since the aorta is the main blood vessel, which carries all blood from the heart and from which all other arteries of the body branch, it is the best object for study.
Now FOR THE INVESTIGATION OF DR. MYERS AND Mr. LANG
Aortas were taken at autopsy from eighty-three persons, who ranged in age from 15 to 88 years. Portions of the vessels were cut into small pieces and mixed, and then chemical analyses were made to determine the proportion of elastin, collagen, and muscle.
The highest proportion of elastin, 47.4 per cent, was found in the aorta of an individual 15 years of age; the lowest, 20 per cent, in an individual 83 years of age. However, the lowest proportion of col- lagen, 11.8 per cent, was found at the age of 45, and the highest, 24.3 per cent, in an individual aged 88, all values being for dry weight.
With advancing age there appeared to be a definite decline in the average elastin and muscle content of the aorta, with a leveling off at the age of about 45 years. However, the collagen remained relatively constant up to about the age of 45 and then increased slowly through the remaining years of life.
INTERPRETATION
Dr. Myers and Mr. Lang present observations which are essentially factual. They have added chemical proof of the changes in elastic tissue with increasing age.
At the present time we do not know how to influence this change of age. Perhaps in the future we may be able to apply the knowledge.
Science must gradually accumulate facts as electricity is built up in a condenser. When a certain value is reached, all the electricity is discharged or all the facts add up to some useful generalization. Until that time we simply store the facts in a condenser or journal.
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The Effect of Yeast Nucleic Acid on the Survival ‘Time of 600 Day Old Albino Mice
THOMAS S. GARDNER
oer" matter is made up of cells, as bricks make up a house. These cells can be seen, of course, only under a microscope, but a great deal has come to be known about their composition. Within the cell wall are jellylike cytoplasm and one or many nuclei. The nucleus is the essential part of the cell-—as is illustrated by the red blood cells which contain no nuclei and thus are destined for death from the moment of their formation in the bone marrow.
The nuclei of the cells are composed of many things, but one of the essential constituents is nucleic acid. The well known disease called gout is a disturbance in the metabolism of nucleic acid in the body.
There are two main varieties of nucleic acid, known as thymus nucleic acid and yeast nucleic acid respectively. Thymus nucleic acid (desoxyribonucleic acid) is obtained chiefly from the thymus gland (one of the “‘sweetbread”’ glands) of animals, but also from the nuclei of rye embryos and yeast. Yeast nucleic acid (ribonucleic acid)