Document dn74V9xOkZRKnJox59vzEdaL0

) \ 155% Je MedicalCenter NEARS HATH SCE CENTER June 18,2004 ROLEAG WICTOHOLO John L. Butenhoff, Ph.D. 3M Corporate Toxicology and Regulatory Services 3M Center, Building 0220-02-E-02 St. Paul, Minnesota 55144-1000 ~ Dear John, I have reviewed the two-volume document entitled "Perfluorooctanesulfonyl Fluoride (POSF; T7661.4), Toxicity Study by Inhalation Administration to CD Rats for 13 Weeks Followed by a 4 Week Recovery Period (Vol. 1&2). You asked me to specifically review thechangesregardingthe `urinary tract, and especiallythe scanning electron microscopic findings reported in Vol. 2. Overall, it appears that the major tissue treatment-related effect is in the liver. From what I understand, you have additional information regarding the effects of this compound on the liver, indicating that it is quite possibly related to peroxisome proliferation. Iwill not comment further regarding the liver changes. With respect to the urinary tract, they list sporadic changes in the kidney, whichI have described in the review of the slides in the paragraphs above. AgainI, do not see anything here that suggests treatment-related effects on the kidney. `Withrespectto the urinary bladder, by light microscopy theyareall listed as normal. By scanning electron microscopy, it is my impression that these also are normal. Again, there is no indication as 10 whichofthe photomicrographs belong to which treatment groups, buIt do not see anything in any ofthe electron micrographsofthe urothelium to suggest any abnormalities in anyofthe animals. Manyofthe animals show separationofthe urothelial cellsofthe superficial layer, which isusually indicative ofoverdistenotfitohne bladder with fixaattthietvimeeofpreservation. In addition, there are some slight changesofoccasional cell necrosis ofsuperficial cells, but again, this is a normal finding as long as it is not extensive and is seen in only one or two cells at a time, rather than large areas. | do not see any such large areas in anyofthe sections portrayed. Based on the classification system that we devised for examination of subtle changes of rat urinary bladder (Scanning Microscopy, 4:135-142, 1990), I would classify all of these bladders as a 1 or a 2, which are considered normal. 983135 Nebroska Medical Center / Omaho, NE 68198-3135 / 402-559-6388 / FAX: 402-559-9297 / www.unme.edu John L. Butenhoff, Ph.D. July 18,2004 Page2 Itis a bit unclear as to methodologyof the preparationofthese samples. Were the animals under aannedstthheesnipalaatctehdeitnifmiexoaftfiivex?atIifotnhoeflatthteerbmleatdhdoerd,,osrweoroefmtthheeeasneismiaglhstkiclhlaendgeasndwtehesebelainddseormseroefmtohveesde bladders could well be due to autolysis, which occurs within 60 secondsofthe time that an animal dies (J. Natl. Cancer Inst., 90: 19-25, 1998). Regarofdthle sepecsifsic methodology, | would classify allofthese bladders as normal. Also, the scanning electron `mostly illustrated examples micrographs ofthe urinary sediment I of single or aggregatesof magnesium consider all ammonium normal. There are phosphate crystals, `which are a normal constituentofrat urine urinary solids in anyofthese photographs. (as well as most other mammals). 1 see no abnormal `The PCNA staining for cell proliferation showed no differences betweenthe treated and controls, `angegaaitnis ve uobsperpvatotihornesctobnycilluingshitg omnitchraotstchoeprye,wsacasnnnoinegfefelcetcotrnotnhemiucrrionsarcyopbyl,adadnedrPurCoNthAelliaubme.liWngitinhdtehxe, it can strongly be concluded that there isno effecton the urothelium in this study. Scanning electron t`hmeiscerowsecroepycaomnpdlleatbeellyinngegiantdievxeairnetphairstsitcuudlyar.ly sensitive in detecting early urothelial changes, and Examinationofurinary parameters also showed no differences secondary to treatment, although it is a bit difficult to ascertain the exact methodology used for collection and examinationofthese specimens. The adequate way for fact that ov examining ernight urines were collected is not specimens. Also, notproviding food the and best way, but is certainly an water during collecotfitohne urine is not optimum for identifying changes, but the fact that no changes were observed in urine specimensand that there were no no changeswere observed in the significant treatment-related uefrfoetchtesloinumourfina aryn ocfoty mhpeosaintiimoanl,s,urI icnaanroynlsye conclude diment, or the urothelium. In summary, I do not see any evidence of a treatment related effect on the urinary tract, including kidneys and urinary bladder, in resptootrneatsmeent with POSF by inhalation. Sincerely yours, SMC:et Lon SZ Samuel M. Cohen, M.D., Ph.D. Professor and Chair, Pathology and Microbiology Havlik-Wall Professor of Oncology