Document DyBNdDM8jJowkQpZKB3KQw2o

* PO Box No 6 Oesaemer Road Welwyn Garden City Hertfordshire AL7 1HD Telephone Welwyn Garden 23400 (STD Code 07073) Telex 264291 Dr J T Barr Air Products & Chemicals Inc Box 538 Allentown Pa 18105 USA Imperial Chemical Industries Limited Plastics Division Your ref. Our ref JS/SEW/DSO-16 Dear John VQJ - MALTONI Tei ext 3162 Date 28 January 1981 Tou may care to have a copy of a letter dated 22 January which I have had from Dr Tassignon of Solvsy. 1 think this should be helpful to you in your analysis of Maltoni's work* I am inclined to agree with Dr Tassignon that Maitoui'a method of handling control animals is important but it will not have much impact on ontside audiences* I was interested that Geoff Paddle had sent to you on a personal basis a translation ve made of a very good treatise by Dr Tassignon* 1 have asked Solvay several times that they should publish this, but my requests have been ignored to date. I thought it was a very helpful paper by Tassignon and so far it has been circulated only to the four Maltoni sponsors in Europe* With best wishes. Yours sincerely J Stafford Division Manager Health it Environment Protection in England No. 218019 Rcgittwad Offict - Imoariat Chrnieat Houw. Millbank, London SW1P 3JF. AP00019417 ; SOLVAY& Cie joci*i anonym* direction centrate dupersonnel R4f i DCP/JPTspdr 3L.Cr.fjl D, we Kit?-E1. ? ; D U nXW Brussels, 22nd January, 1981. Dr J. STAFFORD ICX Ltd/^lastics Division P.O. Box nr 6 Bessemer Road GB - WELWYN GARDEN CITY HERTFORDSHIRE AL 7 1 HD Dear John, In Preparing Newsletter Nr 2 to the members of the VCM Medical Committee, I came across one of your letters dated October 16th, 1980, in which you seemed to be puzzled about John BARR's - Air Products - finding that there are discrepancies between the tables in MALTONI's publications relating to the VCM project. We were all aware of such discrepancies in the statistical group set up by the sponsors. They are to be explained by the fact that MALTONI repeatedly went back to the raw data and reexamined his slides as well as the tissue blocks. I went through 9 presentations of the "final results" of experiment BT 1 on Sprague-Dawley rats with concentrations in the air from 10,000 ppm down to 50 ppm : A. Environ. Res., 7:387, 1974; B. Med. Lav., 65:421, 1974; C. Medichem 2nd International Symposium, Milano 28-29 Oct. 1974; D. Gli Ospedali della Vita 1:7, 1974; E. Ann. N.Y. Acad. Sci. 246:195, 1975; F. Colloque scientifique k la Fondation Curie, Paris 2 Mar. 1976; G. Ann. N.Y. Acad. Sci., 271:431, 1976; H. INSERM Symposia Series, 52:127, 1976; I. Colloque scientifique & la Fondation Curie, Paris 10 Nov. 1979. There is a first discrepancy between publications A and B. In publication A, the data for the concentrations at 250 and 50 ppm as well as the control group were only provisional since a few animals were still alive. Neverthe less, MALTONI corrected almost all the figures relevant to the other concentrations in the following articles he published in 1974. rue du prince abert,33-1050 bruxelles (3.02/51159.40 telex 21337 tgtegrammes sdvayco bruxelles tua 403.091220 tcbcux. 5554 c.cp 000-0000668-86 soc.g4n.debanque 210-0041661-03 AP00019418 2 The trend was upward. Except for a typing error relating to the number of hepatomas at 500 ppm In publication F, MALTONI presented always the same figures* There is a second dis crepancy between the Paris symposium In 1979 and all his previous publications. The trend is upward again# for nephroblastomas# for hepatomas and a substantial rise appea red in the total number of tumour - bearing animals at all dose levels. This is due to the fact that MALTONI went back again to the raw data and picked up new tumours. Other dis crepancies in the 1979 presentation in Paris are due to the fact that the number of animals considered to be exposed in experiment BT 1 was reduced to 30 rats per sex and dose. About 5 animals per sex and dose had been added to the study groups during the course of experiment BT 1 for unknown rea sons. We advised MALTONI to discard them# view the fact that statistical analysis can only be performed on the homo geneous groups originally planned. it is obvious# for those reasons# that the data published as the result of the Paris Symposium in 1979 ought to be considered as the reference data. Another cause of trouble is the fact that MALTONI has a different concept about control groups. During a visit at his institute last month# I learned from the tech nical manager# DAL ZOTTO# that control animals are never introduced into the inhalation chambers. The occurrence of mammary tumours in the exposed group in many of his studies may be explained on the ground of an enormous difference in stress conditions between exposed and non-exposed animals. Indeed# during am important part of the day the exposed ani mals are living in stainless steel rather dark chambers (noise)# in the draft of the ventilation system and the rotating fans# with no food nor water (in the more recent experiments) and with no contact with the outside world. The animals are packed together and temperature and humidity of the cages rise guickly. In the meantime# the control animals are never removed from normal housing conditions. This information will not have a great impact however on the case of vinyl chloride but it is an important consideration in evaluating some borderline effects observed by MALTONI in the mammary gland of rats exposed to other monomers. This information is going to be published in the proceedings of HALTONI1s presentation of long-term bioassay on ethylene dichloride at the Environmental Health Risk Assessment Seminar on ethylene dichloride in Cold Spring Harbour Laboratory on November 15-16# 1979. As there has been very little reaction in the audience to this informa tion# I guess it will not affect MALTONI*s earlier work. with best wishes. tVc-e. . AP000194I9 PO Box No e Bessemer Road Welwyn Garden City Hertfordshire AL71HD Telephone Welwyn Garden 23400 (STD Code 07073) Telex 254251 Dr J T Barr Air Products & Chemicals Inc Box 538 Allentown PA 18105 USA Imperial Chemical Industries Limited ^7 ^80 Plastics . ..^Division Your ref. Our rel JS/SEV/DSO-16 Tel ext 3162 Date 11 November 1980 Dear Jobs VCM - HALTONI I have now heard from Mr J C Thomas that the only results we know published on BT12 and 13 were way back in 1976, as you can see from the attached copy of a letter from JCT. My colleague Geoff Paddle tells me that he and others have noticed the same discrepancies which you mention* We have always presumed that the latest figures are the most accurate ones* I think this is as far as I can go in replying to your letter at this time. At the end of October I was present at the NYAS Workshop on brain tumours and I must say Mai ton! was very fair in everything he said about VCM and brain tumours in animals* The Workshop was not a very great event and VCM was exonerated, though OSHA are still determined that there is an excess of brain tumours in the UCC, Dov and Exxon factories or refineries which they have studied, but they don't know which chemical is causing the brain tumours* With beat wishes* Tours sincerely J Stafford Division Manager Health St Environment Protection Registered in England No. 218019 Regixterrt Office imperial Chemical House. Mjilbank, London SW1P 3JF. AP00019420