Document 2NbgOrkojJy7kk1375LyN89pb

NATURE VOL 240 DECEMBER 29 1972 559 At r4'* Dvurf A - STH Njf" J Nor" J So.-t-I D * J'f Dw-'f _ ft I 5 18 I 3 n lTh>mu> ` N ^ HN prevent ageing is far from clear The most obviouv but in our view insufficient explanation is that these thymus-dependent Cells act in a strictly immunological sense in recognizing and reacting with foreign matter such as viru-is, bacter.a or modi fied self components. While such immunological surveillance is likely to play an important part in life prolongation it does not explain prevention of ageing parameters by lymphocytes. The interpretation we prefer at the present is that lymphocytes can recognize, besides foreign matter, microenvironmental changes, represented by modified host cells or their products. This could result in the cleaning up of such cells and in the release of stimulatory mediators, related to lymphokines, leading to normalization of the area. This view is supported by the experiments on the impairment of the regeneration of liver after adult or neonatal thymectomy'*-14. EURA TOM Unit, N. Fabris Institute of General Biology, Medical Faculty, University of Pavia, Pavia, Italy Schweizerisches Forschungsinstitut, W. Pierpaoli E. SORKIN Medizinische Abteilung, C7/-727Q Davos-Platz, Switzerland Received May 4; revised August 7, 1972. 1 Burnet, F. M,, Brit. Med. 7,2, 720 (1959). * Burnet, F. M,, Lancet, ii, 358 (1970), Hejri 1 Bumet, F. M., Immunological Surveillance (Pergamon Press, Oxford, 1970). * Walford, R. L.,7 Gerontol., 17, 281 (1962). 1 Walford, R. L., The Immunologic Theory of Aging (Munksgaard, Copenhagen, 1969). * Burch. P. R. J., Growth, Disease and Ageing (Oliver and Boyd, - O______________________SSI mi ra____Q___ Edinburgh, 1968). Fig. 3 JH-thymidine (JH-TD) uptake in different tissues of mice injected with 0.8 pCi/g body weight 24 h before sacrifice. Radioactivity was measured in a Tricarb liquid scintillator spectrometer and counts were corrected for quenching and expressed as d.p.m./IQ mg tissue. Old SnelhBagg mice show a decreased thymidine incorporation compared with adult or young animals and a similar decrease is present in J-month-old dwarf mice when compared to the 1-month-old group. Dwarf mice treated in their postweaning period for 30 days with 250 ug growth hormone and 1 pg thyroxine behave at 7 months as do adult normal animals. ' Pierpaoli, W., Fabris, N., and Sorkin, E., in Hormones and the Immune Response (edit, by Wolstenholme, C. E. W., and Knight, 7), 126 (Churchill, London, 1970). * Fabris, N., Pierpaoli, W., and Sorkin, E., Clin. Exp. Immunol., 9.227(1971). * Gruneberg, H., The Genetics of the Mouse, 123 (Martinus Nijoff, The Hague, 1952). 14 Bartke, A., Anat. fire., 149,225 (1964). 11 Garcia, J. F., and Geschwind, I. I., Growth Hormone (edit, by Pecile, A., and Muller, E. E.), 267 (Excerpta Medica Founda tion, Amsterdam, 1968). 11 Fabris, N.. Pierpaoli, W., and Sorkin, E., Clin. Exp. Immunol., 9, 209(1971). I pg L-thyroxine for 30 days. Their life-span was prolonged to 12-14 months instead of the usual 5 months (Fig. 1) and their external appearance was similar to that of normal littermates. 11 Soukupova, M.,and Hoieckova, E., Exp. Cell Res.,33,361 (1964). 14 Fachet, J., Stark, E., Palkovits, M., and Valient, K., 2. Zell- forsch., 60,609 (1963). '* Craddock, K. C. G., Rytomaa, T., and Nakai, G. S., in The *H-thymidine uptake at 7 months of age (Fig. 3), growth poten Thymus in Immunobiology (edit, by Good, R. A., and Gabriel- tial and the percentage of mitosis in spleen and kidney fragments cultured in vitro were also normal. The delay in the onset of ageing symptoms and the pro sen, A. E.), 317 (Harper and Row, New York, 1964). 14 Miller. J. F. A. P., reported by Metcalf, D., in The Thymus (edit, by Metcalf. D ), 86 (Springer-Verlag, 1966). longation of life-span in hormonally reconstituted dwarf mice was not achieved when thymectomy in young adult age preceded the hormonal therapy (Fig. 1), The lymphoid system of the dwarf mice, because of the Tumours of the Nervous System endocrine deficiency, is not fully developed and the life-span is in Mice treated Neonatally with drastically shortened. The full development of the thymus and the thymus-dependent lymphoid cells which can be induced N-Ethyl-N-nitrosourea by hormonal treatment in the postweaning period results in the Tumours of the nervous system are readily induced in rats prevention of early ageing and considerable prolongation of by a single transplacental or neonatal exposure to certain life. Adult normal lymph node lymphocytes transplanted into chemical carcinogens. This suggests that such tumours in young dwarf mice are similarly effective. From these data one man could well be the result of exposure to chemical carcino could deduce that intrinsic environmental factors, such as gens during foetal or early life. Druckrey et al. have studied hormones, determine the functional level of the thymus and through its main cellular product, the lymphocyte, control the nervous system carcinogenesis in rats using the nitrosamide N-ethyl-N-nitrosourea, CiH|N(NO)CONHj (ENU), admini ageing processes. Therefore we wish to propose with Bumet1 stered both transplacentally1'1 and to newborn or very young that the thymus might be considered as an important organ for animals4. Our own experiments with ENU administered to ageing control of body tissues. One could predict then that the day-old rats4agreed with these results in that a single 10 mg kg*' longer the thymus functions at its optimal level either as dose was sufficient to induce neural tumours in nearly 100 producer of humoral factors and'or lymphocytes, the longer of treated animals, but differed in that in our rats a much will be the life-span. higher proportion of tumours occurred in the brain rather The way in which lymphocytes might prolong life and than in the peripheral nervous system. OLI 6802 560 There has been little work in other species. but neural tu-noa-s have been induced in the rabbit11 and the dog1, using repeated administrations of N-mcthyl-N-nitrosourea. Treatment with these carcinogens has not induced tumours of the ne'sous system in mice. Methylmtrosourea administered to adult mice gave rise to thymic lymphomas"1. Mice treated neonatally developed lymphomas' or lymphosarcomas', and intra cerebral inoculation resulted only in leukaemia and lung tumours10, ENL) administered to female mice at about the 16th day of pregnancy resulted in multiple lung tumours in the offspring but no neural tumours", though evidence of CN'S damage was noted. We have examined this apparent resistance of the murine nervous system to nitrosamide carcinogens. The effects of administering a range of doses of ENU to newborn mice of the four pure-line strains at present maintained in our labora tories, A, C57BL, IF and DBA Bcr, were studied. We have now observed a number of nervous system tumours which are believed to be the first induced in mice by a systemically acting carcinogen. Sixteen day-old litters of each strain were injected sub cutaneously with a saline solution of freshly dissolved ENU at doses of 10 to 160 mg kg*1 body weight. The volume injected was 0 02 ml. g"1 body wight, and controls were treated similarly with normal saline. The final number of mice used were 113 of strain A. 94 C57BL, 88 IF and 104 DBA Bcr, Mice were weaned at 3-4 weeks old (or later if necessary) and were maintained on `Thompson cube diet 42' and tap water ad lib. Whenever possible animals showing evidence of tumours were killed for histological examination. Material, including the nervous sy stems of the affected animals, was fixed in formalin : acetic acid : methanol mixture (1 : 1 : 8), embedded in paraffin wax, and sections were stained by routine staining techniques. Nervous system tumours have been found in ten mice, particulars of which are summarized in Table 1. These tumours gave rise to less visible disturbance than those seen in rats despite the considerable size of some of the lesions, as only four of the ten mice showed any degree of hind limb paralysis, and in two of these it was only slight. The tumours can be allocated to two groups, those in the hindbrain arising between 20 and 28 weeks, and those in the peripheral nervous system, of which the first was found in a high-dose mouse at 40 weeks. There may be tumours tn the animals still surviving, and a detailed report will be submitted later. Although comparable numbers of mice of each strain were used, the ten mice with neural tumours belonged to only two of these, five IF and five DBA. Even these tumours have developed in only a small proportion of the animals at risk but thymic or splenic ly mphomas have occurred in larger numbers. At this stage, A and C?"BL mice appear to be resistant to neural carcinogenesis by nitrosamides, like those strains u>ed by other workers""11. Table 1 Nervous System Tumours in Mice treated Neonatally with N-Ethyl-N-rntrosOure* Strain DBA IF IF IF IF* IF DBA DBA DBA DBA Mouse Sex Dose rngkg-' M 80 M 80 M 80 M 80 M 120 F 120 F 40 F 40 M 10 M 20 Age at Tumours death tn1 Location Tvpe weeks 20 Cerebellum Oligoastrocytoma 20 Cerebellum Medulloblastoma 2T Cerebellum Medulloblastoma 26 Cerebellum Medulloblastoma 40 Cranial nerve Schwannoma Rrach'.a) nent Schwannoma 41 Scianc ner\e Nff 50 Cranial nerve Neuroblastoma Schwannoma 57 Spinal nerve S-hwar.noma *9 Sp.r.ai nerve Scltwannomi 69 Spinal nerve Schwannoma 4 r- V e'-r d \pp. i'v of r.eputpcar cir.pwva ,n :he liver NATURE VOL 2*0 DECEMBER 29 1972 The location of the four brain tumours is interesting. All were situated in the cerebellum, three of these being medullo blastomas. All these were male mice which had received ENU at 80 mg kg-1. This high proportion of cerebellar tumour* again contrasts sharply with results obtained in rits1and suggests that IF or DBA mice, or their hybrids, may provide a useful experimental model for the study of these tumour*. We believe the experimental medulloblastomas obtained will help to clarify the controversial question of the origin of these tumours in man. We thank Professors D. G. Harnden and W. T. Smith for their interest. Misses M, Trumper and V. Nash for technical assistance, and the Cancer Research Campaign for financial support. C. E. Searle Department of Cancer Studies, E. L. Jones Department of Pathology, University of Birmingham, The Medical School, Birmingham BIS 2TJ Received September 4, 1972. Ivankovic, S., and Druckrey, H.. Z. Krebsforsch,, 71, 320 (1968). 5 Wechsler, W., Kleihues, P., Matsumoto, S., ZGIch. K. J., lvankovic, S., Preussmann, R., and Druckrey, H., Ann. A Y Acad. Sci., IS9, 360 (1969). ' Druckrey, H., Schagen, B., and Ivankovic, S.. Z. Krebsforsch., 74, 141(1970). 4 Jones, E, L., Searle, C. E., and Smith, W. T., J. Pathol, (in the press). * Stavrou, D., Z. Krebsforsch., 73, 98 (1969). 4 Warzog, R., Schneider, J., Schreiber, D., and Janisch, W., Experirntia, 26, 303 (1970). ' Fret.J. V., Proc. Amer. Ass. Cane. Res., 10, 26(1969). * Terracini. B.and Stramignoni, A., Europ. J. Cancer, 3,435 (1968). * Terracini, B., and Testa, M. C., Brit. J. Cancer, 24, 588(1970). 10 Kelly. M. G,, O'Hara, R. W., Yancey, S. T., and Botkin, C., J. Nat. Cancer Inst,4\, 619 (1968). 11 Rice. J. M,, Ann. NY Acad. Sci., 163, 813 (1969). The Suppression of Non-specific Esterase Activity in Mouse Skin Sebaceous Gland by "CS" Gas In spite of the widespread use of the compound o-chlorobenzylidenemalononitrile (CS)1*5 as a riot control agent there appears to be no published data on its carcinogenic activity*-*, although the usefulness of CS as a riot control agent has been stressed because of the relatively wide margin between effective and toxic doses*. We report here testing of CS with a rapid bio-assay sy stem which has been used as a predictive screening test for carcino genesis. This bio-assay system involves the application of the test compound to mouse skin, followed by the evaluation of the area of skin sebaceous gland non-specific esterase activ ity*"' which can be accurately and rapidly obtained with an image analysing computer. The application of well-known carcinogens and tobacco condensates to mouse skin causes suppression of sebaceous gland non-specific esterase activity whereas the non-carcinogens and irritants, so far tested, do not possess this ability. The degree of suppression has also been found to correlate with the known potency of the carcinogenic compounds. CS is known to react readily with thiol groups at nearly neutral pH (refs. 10-12). As this reaction could account for the suppression of non-specific esterase activity, the related nP-unsaturated compounds cinnamonitrile and cinnamaldehy de were also included in the experiments. The reactivity of these cif'-unsaturated compounds with the thiol, glutathione, was in the order CSacinnamaldehvde>cinnamonitrile. Groups of eight CFLP female mice, a hysterectomy-derived strain of Swiss origin 50 day old at start of treatment, when the hair growth cycle is in the telogen phase, were painted on 4 O LI 6803