pe . : 3 Thus a a eel] with 46 chronosones ani » fragment would be recomied as as EP having 47 ochrososomes. pe th: sonventl | | ! passes coeS PAQDONES, LM GUUTIE Ag 8NG Gli Cie vere b Be em Lay © ree f scoring a fragwent cea cuwihole chronesone, P Re Bi a The effect 6f X-ray axposure on the ohro:.osame gon- Ea. bo satitution of each patient ie shown im Table % (the firat patient) A and in Table & (the second patient). ras ° The data Crom the firet patient show clearly that | chromosone damage. . + a heavy accumilated dose of X-rays produces conaiderabdle oy ws : Se TT VE yea Me ag ee cat { ts 4 Thia in shown both in sirnifieant changes A in the count distribution and in a considerable increase in the me nusbers of cella carrying chromosones with struotural abnormalities. fs These latter sre of many types and no attempt will be asde te bs describe them in this preliminary commumication; if it ia werth notin;, however, that chromosome fragments are conmom and that fe complex ebnormalities such ee ring chromosozes and dicentrios By are seen (Piga. 2 and 3). re | The data from tha rseeond patient are more informative, is | A eingle Xeray exposure was given on 10/8/60, ani twentyfour houre oF : later two aignificant changes had oacurred. a ; percentage of cells with 46 chremogones had fallen froma 93 to 72, ee and that of cella with structurally abnormal chromosomes had risen BS from 1 to 22. + The fall in the meal cells was due to a rennrkable increase in tho number of celle with 47 chrososomes, which rose a | frea lv to 21%, six blood cultures wore set up but only four were successful, and Sy : of the latter, those of 17/8/60 and 13/8/60 were of poor quality. mY a : At tiie time the This partial failure iteel? aay be associated with some effeet of - pL iedledik , ° . en id irrediation, during the five daye from 12/8/60 watil 17/8/60 |. The unusually lew count of modal celle was still thee. scentage, of cells with chrowoso% structural abnormalities reached a. peau Sithnpsa : present feur dsys after exposure, and on thes fourth day the pere 8 nexinen, a Seore EER TATASERE SEE in oO ly _ oe a re lew? pea .. a me aeee : OSE aeee OT er : rs wes, DOE.ARCHN UVES4 CTSEGRE oeBe . ee me BS ake

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