SESSION IV 21) FREMONT-SMITH: these pecple? Did you do any cultures of white cells on CONARD: Yes, at 10 years we did about 40 cultures for chromosomal studies. , FREMONT-SMITH: CONARD: aberration. Did they show anything out of the usual? They showed persisting aberrations, low levéls of FREMONT-SMITH: More thar. other people would have? CONARD: The exposed people showed a greater incidence of these aberrations than did the unexposed. EISENBUD: I think it should be emphasized that those doses that you show in Figure 42, when translated inco dose units, are just a couple of hundred milligrams. ‘ CONARD: I was going to get around to that in a minute, EISENBUD: Sorry, I didn't meanto anticipate. CONARD: Another isotope that was found was cobalt-60, toa lesser extent, which is about 1/10 the zinc level. We haven't seen any iron-55 in the people but we haven't done any specific studies. EISENBUD: Any what? Have you looked for it? CONARD: Not specifically, no, but we haven't had whole-body. counts now ina couple of years. EISENBUD: You can't do it with whole-body counting. by internal conversion and gives you an electron... CONARD: EISENBUD: It-decays Maybe we'll pick it up in the urine, No. Sample blood. Maybe you have some in your laboratory. What you do is separate out the iron-55 and look at it with a thin crystal. It should be very interesting in that group to see what the iron-55 level is. Iron-55 is an interesting isotope. It has been neglected until now because the emission is a 6 KeV electron which has a range of only one micron in tissue; it has generally been