The Atom and the Life Sciences

At this time the National Association of educational broadcasters presents a special address by Dr Willard F. Libby the Atomic Energy Commission. Dr. Libby will speak on the atom and the life sciences. This address was originally given at Purdue University and tape recorded by radio station WABE a presentation at this time. Here is Dr. Libby present Wessler present HOBDAY members of the chapter. Ladies and gentlemen I'm very very pleased to be with you this afternoon. I have a chance to speak in this beautiful new. On the subject of the symposium. From my point of view I've chosen to call it the atom and the life sciences. It's really a part of your more general subject of the impact of the physical sciences on the life sciences. I shall end Andor.

Emphasize the atom which in the common usage today strangely enough is come to mean not the atom at all but the atomic nucleus. I don't think there's any use flying in the faith base of these trends. But when one says the atom today one really means the atomic nucleus. So my speech is really about the atomic nucleus in the life sciences and it has been proved to be very useful. I'd say the principal applications in points of interest are three first isotopic tracing. Second the effects of radiation derived from the atomic nucleus on tissue. And third this last one we may wonder about the

psychological impact of the nuclear world which has been revealed to us in the last. Decade or self the psychological impact of Atomic Bomb is the psychological impact of the wealth of phenomena which we know lies locked in the atomic nucleus which we're just beginning to tap. The feeling of impotence that mankind has before the strange forces which we didn't know about before and which suddenly come to haunt us and to rule the world. Well these three points first isotopic tracing how the principle of isotopic tracing is that two atoms. And now I'm not talking about nuclear.

I'm talking about ordinary out of two avenues with different nuclei can have identical chemical properties. Now we can understand from the nature of atomic structure that this is a reasonable All situation and we can understand that it is very nearly so. The energy level is that is the mechanics of the electrons rotating around the atomic nuclei which constitute the mechanical machinery of an atom depends so little on the nuclear properties all of it requires is that the nucleus have a number of charges corresponding to the out of the element involved. For example it's going to be hydrogen isotope. Let's have one positive charge. Now there are three kinds of hydrogen isotope mass 1

mass 2 and mass 3. Three different kinds of hydrogen atoms called isotopes of hydrogen differing by as much as three fold in their weight. The latter is called tritium. Then this protium which is mass one and deuterium mass to protium deuterium and tritium the three isotopes of hydrogen you know of course and no other element in the periodic table is there such a dramatic and large difference in masses as in the case of the hydrogen isotopes. Now tritium can be separated from ordinary hydrogen by distillation of the liquid hydrogen rather easily but tritium want it. That is the end of an hour. The water molecule

contains two molecules of hydrogen into atoms of hydrogen and one of water one of oxygen. Pretty in water is rather difficult of separation from ordinary water. Especially when it's diluted in other words the isotopic principle is very nearly satisfied even in the extreme case of the hydrogen isotopes. And remember to recapitulate the isotopic principle is the two atoms with different nuclei can have identical chemical properties. No. As we move up the periodic table from hydrogen the percentage changes in the masses of the isotopes is reduced. For example helium the next element has two isotopes mass 3 and mass for which occur in nature. And then there is a

mass six helium which can be made radioactive for my. Nuclear bombardment machines and then lithium there are two isotopes and one radioactive one two isotopes occurring in nature six and seven and a radioactive one which is extremely short lived and so on come to carbon which is very important. We have two isotopes in nature 12 and 13 and one radioactive one for 30. But the percentage differences in mass as mine are very small and very much smaller than in the case of hydrogen. Now returning to hydrogen take the deuterium case that is the mass to hydrogen. Here we have. Well the water made of deuterium is called Heavy Water deuterium oxide and it is then used to study the effects of volatile isotopic

substitution and to test the principle of isotopes in the experimental way. In fact there are attempts now being made the last of a long series of similar attempts to try to develop organisms or animals which can live on heavy water instead of ordinary water. These this latest attempt is being made at the Argonne National Laboratory by Dr. Joseph Katz and his collaborators in a very interesting attempt to grow animals completely do trade and to develop the point where their protium which has made our main hydrogen isotope is replaced by deuterium. Now it's not easy. He's succeeded to date in introducing about 30 percent in some organisms I'm told. Now it is true that heavy water is very similar to like water

but it's also true that the Bene bollock processes of the body are so delicately balanced that despite the small difference in properties between to tary m oxide and protium oxide in a very real sense every watter in large quantities Allee's is poisonous. These delicate balances are an extremely sensitive way to test the difference between the isotopes of hydrogen and I would say that differing essayed do by Matt factor of two in mass that is to tarry him and protium if it should be possible to introduce as much as 30 percent deuterium into a mouse and still have him live this pretty well substantiates the reality of the principle of isotopes namely

two atoms were different nuclei can have a debt equal chemical properties. Now of course what I'm really saying is that it is true isotopes never have a dental chemical properties what I'm saying is that there are chemical properties are so similar that for most purposes they can be treated as being identical. Now this principle of isotopic tracing was one of the great discoveries of all time I would say was discovered about 40 years ago all by Dr George. Have a say. Now Stockholm he received the Nobel Prize for this achievement. A few years ago and just a few weeks ago he was given the Ford Atoms for Peace Prize for it. It was one of the great steps forward in laboratory technique and the impact of this application of isotopes to the life sciences has been tremendous. I remember at the University of California Berkeley when I was a graduate student

and a young staff member the tremendous burst of enthusiasm with which the life sciences welcomed they appearance of artificially produced radioisotopes as a result of the work of the Ajo of Dr. Julio and his wife Irene Carey in discovering the principle of artificial radioactivity. And then the news of this discovery came to Barclay and Professor Ernest Lawrence's cyclotron was just actually beginning to operate. If I said Gilbert Lewis had just isolated heavy water for the first time they put all these three wonderful things together. That is what they do Terry I'm gas and Professor Lawrence a cyclotron and bombarded the ordinary materials in the way Dr. Julio said they should. And immediately a whole host of new radioactive isotopes appeared on the scene. The life sciences

proceeded then and they were very much on the tolls. The life scientists proceeded then to go on tremendous excursions into new uncharted territory and for years before World War 2 a large fraction of the papers from the life sciences department of the Berkeley campus university California involved the use of radio isotopes one of my students at the university Dr. Samuel Reuben undertook first to apply radioactive carbon which I believe to be the most important single isotope for the life sciences to the problem of photosynthesis. Dr. Rubin was co-discoverer of radio carbon. I've given him the task of searching for it as his thesis problem. But this proved to be premature that he got of a year or two later when the after deck in his degree on seven other theses. As soon as the intense cyclotron beams became available he

was a most versatile man. I would recommend you read as the system. It's a great tragedy that he lost his life in 1943 before he died. He really made tremendous contributions and the application of isotopes not only to the life sciences but the physical inorganic chemistry and physics we undertook to put carbon 14 to work on the classic problem of photo synthesis. And his papers are still classics. The work has been carried on in recent years by Professor Calvin of the Berkeley campus the University of California and by Dr. Hans guy friend and Professor James Franco University of Chicago with other groups and other places in the world contributing but these being the two main centers and I think Dr. Calvin's group is by far the leading role in the ET investigation for the synthesis using isotopic tracers in particular radioactive carbon. Now this

work has did eliminated the problem of photosynthesis and though it is not has not solved it completely we have gained an understanding of the fundamental chemical cycles which are determinative in the system. This knowledge will of course be basic to a final solution of the mysteries of plant life and of all of the significant and cell arrays that follow from. Radioactive carbon 14 has been widely used in the studies of the metabolic processes of the human body and will be even more widely used in the future when the methods of sensitive major modes which have been developed in other connections are applied to the utilization of this isotope in the study of normal human brains. For example at the University of Chicago Medical School there is a very gifted researcher and clinical medical man Dr. George Tiller Rai who is now

using radio Parman on normal human beings for the development of routine diagnostic tests for illnesses and the anomalous anomalies which doctors deal with. The results are very starkly. Dr. Leroy is completely satisfied now that this is a real goldmine of new diagnostic techniques which will be of great value to the practicing physician and everyday use. I'm not speaking of research I was speaking of the practicing physician and I'm speaking of his using radiocarbon containing pills. But she will give the patient for diagnostic purposes using very small amounts and taking advantage of the extreme sensitivity of modern measurement techniques so that the radiation hazard is minimal. About 10 years ago all with this dream in mind a group of us at the University of

Chicago and at the Argonne National Laboratory started what we call the isotope farm. Professor Gaia wing of the department of pharmacology undertook to culture the foxglove plant to obtain radio active digit toxin for the Study of the metabolism and pharmacology of this very important heart drug techniques which he had developed for laboratory culture of this plant and similar techniques which had been developed at Brookhaven on a laboratory scale for the production of radioactive sugar. Together with certain other developments were assembled in a procedure for the culture of crops of various plants on the scale of a totally enclosed hermetically sealed room about the size of an ordinary bathroom. It has glass panels through which the light sunlight and fluorescent lights as a supplement enters.

And there's running water over the glass panels to take away the heat generated and trapped by the greenhouse effect. The number of these growth chambers were assembled in an ordinary greenhouse which also had facilitates for culturing plants an ordinary way so they could be carried from the seedling stage up to an appropriate point in their development at which point they would be transplanted into the radioactive growth chamber where they would be fed radioactive carbon dioxide. You know as I say the growth chamber contains carbon dioxide which had a high content approximately 1 percent by isotope of carbon 14. And the carbon 14 isotope content of the gases CO2 was carefully controlled to make certain that the radioactive carbon that was assimilated in the plant was assimilated.

A constant specific activity. Dr. Norbert Scully developed and built the first isotope farm at the Argonne National Laboratory. A second has now been built and installed at the Medical College of Virginia in Richmond under the direction of Professor Paul Stanley Larsen and his collaborators Dr. Scott Lee grew and has grown in the years since the farm went into commission. Many different kinds of plants and harvested them and stored and in some instances process to the harvest of plants. These may add many interesting experience. One of them I recall as well amuse you I'm sure. And there was a a in the early stages. It wasn't known just how to handle AIDS radioactive sugar beets and the horrors of the foxgloves and all these different kinds of radioactive plants that

came out of these growth chambers after the crops had been matured. Well in the early days the habit was to dry them and then powder them and put them in models. Now these plants are quite radioactive as I say they had 1 percent of their carbon atoms carbon 14 their self radiation dose was 20000 Renton's productive. That is their own radiation would give them 20000 Renton's of dose per day. As I recall the number. Well they puttering in the plant apparently made a little dust and in the first months of the operation of the farm the farmers were getting radioactive. And I my contribution other than to help get things started was to measure their haircut. So whenever they had their hair cut I'd get the hair and we'd Meijer it and out we had one girl who became quite

radioactive. She went up to seven times a normal radio carbon content and then she went back down again. We watched this happen over a matter of several months. One of the men farmers also got a little bent but of course these are way below the tolerance figures that is a given but I think probably miss Stroud was the first radioactive woman. No. Another interesting experience was the discrimination which plants make between radioactive CO2 and ordinary CO2. As I said ordinary carbon atoms consist of a mixture of all of the isotopes 12 and 13 and I've also said that they chemical properties of carbon 14 very similar to those of the ordinary carbon atoms. So one might

suppose at first sight that the growth chambers would not show any shift in the specific radioactivity of the residual CO2 in the gas phase. But as I pointed out a moment ago all the life processes are so nicely balanced that they are built to emphasize isotopic differences. Now it is known from the atomic weight measurements and isotopic analyses of organic matter that organic matter is less is lower in his carbon 13 content. Then there is atmospheric carbon dioxide from which organic matter is derived. Therefore it was not surprising to learn that during the daytime that is during the period when the plants were growing the gas phase in the growth chamber got richer and richer and richer and in radioactivity as a nine chamber hanging in the gap in the growth chamber would

increase its response for the raising of nap. That is when corrected for pressure but of course we kept that pressure. We kept the sea for a CO2 up and there would be a tendency for the c14 to be left behind and the ordinary carbon to be assimilated into the plant. During during night time this thing was reversed to a certain extent and it was necessary therefore to keep careful track of the composition of the gas phase in order to ensure that the chemicals which were being formed in the plant would have uniform specific activity because our objective was was to make all the chemicals in the plant uniformly radioactive. Now at the present time large quantities of plants which are thus have thus been grown are stored in the Argonne National

Laboratory in a preserved condition waiting and ready for an application that anyone competently train wants to make. It is merely necessary to apply to the Atomic Energy Commission by writing either to the Atomic Energy Commission Office of isotope development or to the Argonne National Laboratory division of biology and medicine. The potential for producing radioactive drugs and bio chemicals from this supply is of course enormous. It is safe to say I think that from this supply and particularly from this technique which one could extend to isotopic farming procedure to include animals as was originally planned. Dr Scully's preoccupation with plant life was as a botanist never encouraged him to proceed to the animals. Every known pharmaceutical plant origin or animal large might

be supplied in radio active form in this manner. Now there are two or three aspects of the point which are of real interest. One is that these intensely radioactive plants produce chemicals which are self destroy. With a lifetime of a few months that is the radiation is so intense that they destroyed themselves in a few months. So you had to continually reap your five unless you die look to where the ordinary non-radioactive drugs like to talks. If you wanted to preserve it you could preserve and dilute it with ordinary Daedra toxin. And in this way reduce the self damage. Now you wouldn't want to use the intensely radioactive drugs on humans anyhow. They'd be too dangerous. You want to dilute them and sell they dilution will probably be necessary in due course before they're put to actual use. And so it appears that one is likely to have to dilute these chemicals in order to

use them in order to preserve it. So all the drugs and pharmaceuticals that are now used in modern medicine can be made radioactive. Now if that isn't a magnificent opportunity for the life sciences I've never seen one. So far there's only one man doing the work. We've had these farms going now far a number of years. But a doctor in the Rye I believe is the only clinical doctor now working on this technique and I do hope that others will take it up. In fact to date radiocarbon has been use very little though obviously it will be in the end the most important of the tracer isotopes for the life sciences. It's hard to understand why this is because of it maybe because because

it was discovered late as compared to some of the other isotopes isotope was phosphorus was one of the first discovered and it got started at Berkeley. Almost as soon as it was born and the various biological applications which were very dramatic and sulphur came along then sulphur 35 and radioactive fire and chlorine and IED. Now these are important but relatively minor elements of the human body. They were used first and have still received the widest use. You know there's a large scale and widespread use of radio ion for thyroid thyroid diagnosis and therapy and radio phosphorus has been widely used in the study of leukemia. Following the early work of Dr John Locke Lawrence of Berkeley. Biology he has as have the life sciences in general benefited

enormously from the atom and will benefit even more enormously in the future if we take advantage of the opportunities to make up locations of these presently relatively on use isotopes radioactive carbon and radioactive hydrogen. Now I've been talking a lot about carbon but the same story applies to radioactive hydrogen tritium. It also has not been used in biology to anything like the degree which it can be use. With the exception of these two Most of the isotopes one thinks of as being naturally applicable to life science problems have been put to good hard work and their potentialities fairly well developed. I will certainly look forward to growth in the direction of the application of these of these important isotopes and the development of a routine technique of using radioactive pills in ordinary diagnostic

taps. The methods of measurement become so sensitive that the amount of radioisotope really required is minimal and well below even the most conservative tolerance numbers. Now I'd like to turn to the second application of it. They Tomic nucleus to the life sciences. These are the effects of atomic weight. That is nuclear radiation on living systems. Ever since the discovery of x rays we've been increasingly aware that tissues are affected by X-rays and gamma radiation and we've learned in more recent times that in fact all ionizing particles produce similar and somewhat more concentrated effects. In general these facts can be put to use in the destruction of cancerous tissue and similar applications. We can observe the deleterious effects of excessive doses of radiation and these have

received much attention recently in connection with the problem of radioactive fallout from nuclear bomb test explosion. The widespread interest in the social logical aspects of radioactive fallout from nuclear testing has led us to look more closely into the problems of radio biology. At the end of World War 2 the University of Chicago organized three new post-doctoral research institutes the Institute for nuclear studies which is now known as Enrico Fermi Institute for nuclear studies the Institute for the Study of metals and the Institute for radio biology. Now the first two institutes are still flourishing at the university but unfortunately the radio biology effort has largely subsided. Not through any lack of interest in the field but through a strange set of local circumstances which have no general significance.