Stratospheric Fallout of Strontium-89 and Barium-140

A series of nuclear test explosions which occurred in the fall of 1958 caused a very large increase of Sr(89) and Ba(140) in the stratosphere. The Ba(140)/Sr(89) ratio in the stratosphere, and hence in the troposphere, has decreased steadily since then with a half-life of approximately 17 days.

Radioactivity of people and foods

Measurements of the cesium-137 content of people and of foodstuffs indicate that this nuclide is unlikely to be a decisive factor in the long-term hazards from weapons testing and reactor waste disposal. The amount of cesium-137 now present in the population of the United States averages 0.006 microcurie and shows no marked dependence on geographic location. The average radiation dose received from cesium-137 is one-twentieth of that received from natural radiopotassium and 1 percent of the average total dose from all natural sources. Because of the short biological half-life of cesium of about 140 days, it does not accumulate in the body as does strontium-90. The study of the distribution of cesium-137 is being continued to furnish information on the mechanisms of the fallout process and provide a measure of the rate of fallout and of stratospheric storage.

Efficiency of glutamyl peptide polymers as plasma volume extenders

A series of polymers of polyglutamic acid have been tested as plasma volume expanders. The results indicate that those polymers prepared from backbones of 40,000 molecular weight or over and side chains of 3,000 molecular weight or over, will have plasma volume retention half-life of 15 hours or longer. Measurements of the oncotic efficiency of these polymers in vivo indicated a blood stream fluid retention of approximately 51 ml./gm. of polymer. Similar measurements of polymer-serum albumin solutions in vitro showed a retention of 52 ml./gm. of polymer. The clinical response to infusion of solutions of these polymers indicated no untoward pharmacological properties. Although the number of trials presented is too small for ultimate conclusion regarding either the physiological or clinical effects of these polymers, they do provide a strong indication of the desirability of further clinical testing of this polymer and a sound basis on which to plan the larger scale preparation of polymer. Both measures are currently under way.

Studies on copper metabolism. XIX. The kinetics of iron metabolism and erythrocyte life-span in copper-deficient swine

Ferrokinetic studies were performed in three copper-deficient swine and the results have been compared with similar studies in 18 normal pigs. The mean value for the plasma iron turnover rate in the deficient swine was 1.76 mg./kg. day; for the red cell iron incorporation rate, 1.24 mg./kg. day; for the red cell iron turnover rate, 1.18 mg./kg. day; for the red cell life span, 13 days. Corresponding figures in the normal swine were 1.11 mg./kg. day, 1.01 mg./kg. day, 0.59 mg./kg. day and 63 days, respectively. The red cell life span was measured by the use of radioactive chromium in a total of 26 pigs. The mean erythrocyte half-life of normal cells transfused into normal pigs was 17 days. The mean half-life of erythrocytes from copperdeficient swine transfused into copper-deficient swine was 9 days. The mean half-life of red cells from control animals transfused into copper-deficient swine was 16 days while that of erythrocytes from copper-deficient swine transfused into normal pigs, was 13 days. The mean half-life of cells from iron-deficient pigs transfused into iron-deficient pigs was 19 days. It is concluded that copper deficiency anemia results from both a shortened erythrocyte survival time and limited capacity of the bone marrow to produce red cells. It is suggested that copper is an essential component of erythrocytes in swine.

On the reproduction of influenza virus; quantitative studies with procedures which enumerate infective and hemagglutinating virus particles

Procedures which make possible the enumeration of both infective and hemagglutinating influenza A virus particles have been developed and used in a quantitative investigation on the reproduction of the agent. Infective particles were found to be highly unstable and their half-life was only 147 minutes in allantoic fluid at 35 degrees C. both in vitro and in vivo. The instability of infective particles provides an explanation for the rapid accumulation of non-infective particles which retained the hemagglutinating property. The number of non-infective (N) particles was determined from the difference between the number of hemagglutinating (H) particles and the number of infective (I) particles as indicated by the relation: [N] = [H]- [1]. When the half-life of infective particles was taken into account, both infective and hemagglutinating particles were found to disappear from the allantoic fluid; i.e., were adsorbed by the allantoic membrane, at the same logarithmic rate after inoculation. Inoculation of any number of particles up to 3 x 10(7) was followed by a constant and progressive decrease in the proportion of unadsorbed particles from 0 to 4 hours. Approximately 20 per cent of particles were unadsorbed at 2 hours and about 5 per cent at 4 hours. Inoculation of 3 x 10(8) or more particles led to a larger proportion of unadsorbed particles at 4 hours. The maximum number of particles adsorbed was computed to be about 1.6 x 10(9). The concentration of both infective and hemagglutinating particles increased rapidly in the allantoic fluid after 4 hours when any number of infective particles up to 3 x 10(7) was inoculated. With such inocula, the rate of increase during the logarithmic period was constant and the time to double the concentration of infective or hemagglutinating particles was 46 minutes. With larger inocula, i.e. 3 x 10(8) particles, the concentrations of infective and hemagglutinating particles did not increase until after 8 hours and the rate of increase was much slower. The time to double the concentration of either then became 92 minutes. The number of infective particles was approximately equal to the number of hemagglutinating particles during the logarithmic increase period when any number of infective particles up to 3 x 10(6) was inoculated and no more than 10(6) non-infective particles were included in the inoculum. This finding was taken to indicate that all or almost all particles produced and released under these conditions were infective. That such particles became inactivated rapidly and led to the accumulation of an increasing number of non-infective particles after the logarithmic period can be explained by the short half-life of infective particles. The number of infective particles was no larger than one-tenth the number of hemagglutinating particles during the logarithmic increase period after 3 x 10(7) or more infective particles had been inoculated or when smaller inocula were used which also contained 3 x 10(7) or more non-infective particles. Non-infective particles prepared in vitro at 35 degrees or 22 degrees C. were as effective as those which accumulated in vivo in diminishing the proportion of infective particles in the yield. The extent of the reduction in the proportion of infective particles was directly related to the number of non-infective particles included in the inoculum. The yield of hemagglutinating particles was diminished when the inoculum contained 3 x 10(7) or more non-infective particles. The rate of increase was reduced so that the time to double the concentration became 92 minutes when the inoculum contained 3 x 10(8) non-infective particles. It appears from these findings that the single condition which will lead to the emergence of non-infective particles during the logarithmic period is a high initial particle-cell ratio. Because non-infective particles are equally as effective as infective particles in producing this result, it seems probable that the appearance of non-infective but hemagglutinating particles is not a necessary accompaniment of the reproductive process.

The half-life on homologous gamma globulin (antibody) in several species

1. The half-lives of homologous gamma globulins labelled with I(131) agree well with the half-lives of passively administered homologous antibodies and provide a simple, quantitative tool for the determination of antibody half-life when immunochemical techniques are difficult to apply. 2. The half-lives of gamma globulin or antibody vary markedly from species to species and apparently even among age groups within a species. 3. The half-lives of gamma globulin or antibody seem to be dependent, at least in part, on the metabolic rate of the host.

The physician and the atomic bomb

ATOMIC DETONATIONS ARE ESSENTIALLY OF TWO TYPES: contaminating and non-contaminating. The only non-contaminating burst is the high air burst, since it does not result in the contamination of the ground with radioactive bomb residue. This type of burst results in blast, thermal and ionizing radiation injury (often combined in the same patient). The only injurious agent peculiar to atomic warfare is ionizing radiation. With a high air burst these effects are due mainly to gamma rays, and they are no longer present after the first few seconds following the explosion. Although only about 15 per cent of the deaths resulting from this type of burst are likely to be due primarily to ionizing radiations, exposure to the latter may well complicate recovery from trauma. Since there is a latent period of a number of days between the initial and later symptoms and signs of whole body radiation exposure, it does not constitute an emergency and can be treated after the initial period of the disaster has passed. With the detonation of a contaminating burst (a surface, underwater or underground burst) the radii of damage from blast and thermal radiation are considerably less than with a high air burst. Two types of radiation may result from the radioactive fog (base surge) formed after an underwater burst-transit radiation and deposit or continuing radiation. The deposit radiation includes that resulting from inhaled or ingested radioactive material as well as that deposited on clothes or skin. Bomb residue contains material which would localize in bones if it entered the body, and much of it has a long radioactive and biological half-life. It would thus bombard the radiosensitive bone marrow for long periods.Fortunately, the materials which would localize in bone are poorly absorbed from the gastrointestinal tract and lungs. In general radiation injury to a person exposed to a contaminating burst should be reckoned primarily in terms of the penetrating gamma radiation to which he was exposed, rather than in terms of possible internal radiation from ingested or inhaled contaminants. The principles of broad planning, careful triage, decentralization of medical aid, intelligent stockpiling, and the greatest good to the greatest number are to be stressed in medical defense planning. The best appraisal of exposure and its degree of seriousness is, as it is with disease in general, an accurate clinical evaluation by the physician. The tempo of the disease is an important aid in evaluating severity of exposure. The use of the dosimeter in judging the fate of a given individual is, at least at present, of limited value.