: ER ee hone teyhe : 1 casa fa re eat ada a op ithacaela by a Me vn ‘ ‘ z wae el oy torees se See a tg + Santen Fy erettes cra Oatwee des pees he ae haat ticeeters ahha Beta iteEee eae Ne babs bat wvaShleivewb th %re “an ted 2Ser BEBE Races wr ee : ings of Della Rosa & Stannard (95) with we airibuuion did not influence acute me vune diPorent, ciz: LD, versus carcino. 234 aos : hole Pu. Toxicity of 239 Pu has been wiivity basis (96) but the data do aot 6 SOomte americium-24! along with ia 1H Carcinogenicity of *4'Am to 739Py * Hatt~ recently negated earlier findings shes a long-term study in rats. In their 1 Ioy- effective than 23°py in producing Bo te ee ee J otufution follow through the long-term * Ba wcenthal & Lindenbaum(94). In this shoe ‘opctian in monsmeric form was “f » f female mice) thar. similar doses 7 vatnange the monomeric orm began dying ‘oad about twice the incidence both vybers of tumors per niouse, The higher cp or andosteal surfaces of metaphyseal of urortart role in this shenomenon. uo by this explanation alone. The paiyLi eatent toan monomeric in liver and other den cri incidence of hepatomas was 6°% 7 3°, with the monomeric plutoniurn. -itibutes also cannot be decided. Also the « sme degree at very low concentrations of Re REN aew Iee weowGpl WuGes Ui & Piz Lecividg piulumun Niet dorahan et al (93), OF special interest Satyoes the fact that lun lesions seemed .owenk Tnph node damage was more ot FR. COPY al TAL ASALY TY etdet hee sa a - Ob RADIONUCLIDES so CO es 337 BR ee gb rete bbe egy jesion, and one meluaeria or the cheat tas been reported Ij n another individual, hut correlation wath Matai py doesn i very €circumstantial at chis juncture, Natural Crandon. Setveal uraniemy C380 plus emall amounts of “74Uand 734) bas been the senieet on seeerat fongeterm Studies over More than two decades. These ure nos exestaly complere. The eflects of U-nat im soluble t form are seet tPardes as nerhrctovicite ard are attributed to chemical rather than to radiation efecis. In msoluble form the tectts of natural urantum are considtred to Fe ge. to radiation. tat only recently have neoplastic changes been demonstrated with this sere low srecitte acttivity suostance. After up to 5 yeais of exposure to UO, dusi bs inhalation at 5 mg Unat,‘m° on a 5-day per ween sche dre ond a Tastee fare observetian period cf up to 65 years the lone-term Rochester exmer tert (98) has maw shown pulmonars neoplasiu tn 4 of 13 exrosed dozs and epitnebal proliferation and metaplasia in severai others. While this is a definite finding it is somewhat tempered by the fact tha: 25 exposed monkeys in the same experiment have shown only extensive fibrosis and no peoplisia <5 yet. It can be concluded that natural uranium ts clearly not verylikely to produce radiogenic tumors. Conversely, the fact that no kidney damage was seen by any measure, histological or functional, supports the conclusion tha! “insoluble” natural uranium is not likely to show nephrotoxic effects and it. contro) snouid be based on potential radiation damage. However even 2 change to uranium trioxide makes a large difference in pharmacokinetics and thus potential effects as demonstrated by Morrow. Gibb & Beiter (99). Hence any such generalizations should not be extrapolated unduly. CARCINOGENTSIS BY BETA AND Brra-GaM™is Exnrrers In general. nuclices whese carcinogenic uf beia purucles anc or a ganime proton rad than the wipha partile emitters. This bioleg’c:* en€ petr’s also. Recent work of section, action resides primarily in emission are less effeclive as Carcicgens per seems to be true in part for other special interest is summarize | in this Stromtiom and reiated ructides in animiis.—The concern generated by the presence in ihe oiosphere of fission preducts from testing of nuclear weapons in the atmosphereled to massive experimental studies of the behavier and effects or riese nuchides. While much work ty ull in progress many recent reports may be tegardcd as msestones. The pudushea proceeaings of a symposium on radiostiaiteim ex rooure held in Davis. Catiforma in February (47) are now avcdaboe visor Joining up-to-cate Mans aspects of ins large feld. Shirts ano oer oo lenient. are vroserted in : the radiosirentium smrtesium, ME ate , tne pomars and pomt ang cause of ceath i) 9 of these fou pit tad lagi cetatsiogv is Cie pede par emect oad stud. nk toe sand ram. some charces in manin | pil : ‘ wo owleety ita olan dls by inspected radiostrevium 203. 10f ae aes ops with roderts. Tac tumors attributable to the [Sr ¥ sw mm animals receiving 2.5 uCi/kg or re} te 80°,incidence in animals receiving Te ates ued hy the authors to differerces +d. 2 iTKIUM Compared to the sredomi : “es nm binding to plasma proteins. ‘+, sigiuding leukemia, were seen ir Ose ceetaparicon of effectiveness, “en iesions (excent 'ocal denase UU MEURL Werhers i Landes om -Phrenum Reui irs hus tee » thord Environmersal Healin vt to Study this group for com- moginee woeonweeee an Te aha eeeCRABBF DEN ayen \ie ee 10 pen * dota po eae a ey t en ee oe Shy ate J re ee gt 4 ay Hu ed emer lg ad a toy SOMME EBT CR teen Me ertee are Eup ta en oat emp y at od pte , 1 te Ameen t 4, yA ‘ 1 thea vy efor Cee ge tat CSEaal Sey ay Week ae Met SEE marae T-