256
4TH ANNUAL MI:.ETIN(;, ItEII)I-LI-IERC,
in 24-hour intervals. The c o n c e n t r a t i o n s were 5, 25 a n d z25 m g / k g b o d y weight. ~', mtrols received o.5 ml salt solution only. The animals were killed a n d the ~-permat~gonial chromosomes were >pread at interval> ,ff 6, I2, 24 a n d 4,~ h after the secured t r e a t m e n t . In mice (4 for each dose a n d test interval) no e n h a n c e m e n t of the chr~,m,~some a b e r r a t i o n rate b e y o n d the >pontaneou> rate was ~bserved at a n v ~f the three doses (z) a n d (e). In Chinese h a m s t e r in one l a b o r a t o r y (z) there wa> also n~, enhanct'ment of the a b e r r a t i o n rate in a n y group of animals, w h e r e a , p r e l i m i n a r y r,>ult~ from a n o t h e r l a b o r a t o r y (3) with 2 animals in each group showed an increase in the numbel of c h r o m a t i d gaps a n d c h r o n m t i d breaks frw I25 m g / k g 24 h after the second t r e a t merit. These results, hmvever, have to be checked again in a n o t h e r e x p e r i m e n t . Long t e r m t r e a t m e n t of mice a n d Chinese h a m s t e r s (3 t r e a t m e n t s per week f~r i2 weeks) with 25 m g / k g in one l a b o r a t o r y (1) did not change the a b e r r a t i o n rate c~mlpared with the controls. B y far the most a b e r r a t i o n s found in these e x p e r i m e n t s were z -2 g a t > per m e t a p h a s e . Cells with lnore t h a n 2 gaps or with break>, fragments and fusi~uls were seldom found.
/~6 ADLER, I.-D., A b t e i l u n g ftir Genetik, Gesellschaft ffir Strahlen- und Umweltfiwschung, N e u h e r b e r g (West G e r m a n y ) , a n d D. MOLLER, D e p a r t m e n t of E x p e r i m e n t a l Toxic~> logy, Ciba-Geigy A. G., Basle (Switzerland).
Chromosome analysis in spermatocytes of mice and Chinese hamsters The s t u d y of meiotic chromosomes after t r e a t i n e n t with isoniazid (INH) consisted of two parts. In the acute s t u d y the doses were 5, 25 or 125 m g / k g given twice 24 h a p a r t . S p e r m a t o c y t e s were s a m p l e d xo a n d z z d a y s after the ~econd t r e a t m e n t , thus representing s p e r m a t o c y t e s t r e a t e d at late D N A synthesis to leptotene. In the chronic s t u d y tim mice were t r e a t e d 3 times per week for I2 weeks with I N H at ~5 mg/kg. The s p e r m a t o c y t e s were s a m p l e d 3 ° d a y s after the last injection, at which time t h e y r e p r e s e n t e d t r e a t e d stein-cell s p e r m a t o g o n i a . F o u r animals per dose a n d control were used, a n d Ioo cells per animal were scored. Diakinesis n l e t a p h a s e I chromosomes were a n a l y z e d for the presence (~f univalents, n m l t i v a l e n t s a n d fragments. M e t a p h a s e l I chromo.~omes were a n a l y z e d for f r a g m e n t s a n d a n e u p M d i e s . In the acute s t u d y with mice a n d Chinese balusters the results d i d not differ from the control values. In the chronic s t u d y with mice, 3 presulned m u l t i v a l e n t s were obs e r v e d : two chain m u l t i v a l e n t s d e r i v e d from one male, a n d one ring n m l t i v a l e n t derived from a n o t h e r male. To verify the result ot the chronic s t u d y the n m n b e r of mice tested as well as the n u m b e r ,~l celN scored per mouse have to be in,'reased.
/~7 ~I(~LLER, D., Basle (Switzerland); A. GRAFE, M a n n h e i m ; H. G. MILTENBURGER, D a l m s t a d t ; G. R(SHRBORN, H e i d e l b e r g : a n d M. SCHULZE-SCHENKING, D a r m s t a d t (W. Germany).
Chromosome analysis of bone m a r r o w and nucleus anomaly test in mammals after t r e a t m e n t with I N H The results of tests for p o t e n t i a l m u t a g e n i c ettects of isoniazid I INH) were
EUROPEAN ENVIRONMENTAL MUTAGEN SOCIETY
257
described. The investigations were carried out independently of one another in five different laboratories. On the one hand, chromosomal analyses were made in cells from the bone marrow of Chinese hamsters, rats and mice. In short-term studies, groups of four animals were treated twice with I N H at doses of 5, 25 and 125 mg/kg at an interval of 24 h. The animals were killed at various times (6, 12, 24 and 48 h) after the second dose. In long-term studies a group of four animals received I N H (25 mg/kg) twice a week for 12 weeks, the animals then being killed six hours after the last dose. The investigators usually examined IOO metaphases from each animal. On the other hand, for the nucleus anomaly test groups of six Chinese hamsters were treated according to the same schedules, IOOO cells from each animal being studied. In addition to the dose groups mentioned, experiments were also conducted on controls. In the cytogenetic investigations carried out in different laboratories, in comparison with the controls no significant increase in the incidence of aberrations was detectable in the majority the animals treated and killed according to the foregoing schedule. Only one investigator found, in animals killed 48 h after the second application, as well as in a repeated experiment in animals killed 6 h after the second dose, an increased number of aberrations. The comparison of these values with the corresponding data of the control group showed a significant difference according to regression analysis (P < o.oi). In the long-term experiments of the nacleus anomaly test only one investigator found a significant increase of aberrations in comparison with tile control (Z2 test, P < o.oi). In the short-term experiments with this test a significant deviation was also observed in one case only, the total number of cells with nuclear anomalies 24 h after the second dose being significantly greater than in the control (ff test, P < o.oi). To sum up, it is clear that the results obtained by the various investigators do not show any consistent pattern. If in single cases an increased number of aberrant metaphases and an increased persentage of nuclear anomalies after the application of I N H was seen by few investigators, the findings were still not even remotely comparable with the results observed after the use of known mutagenic substances. Consequently it would be unwise to draw any definitive conclusions about a mutagenic quality of I N H on the strength of these results. Abbreviation: I N H , isoniacid.
48 OBE, G., B. BEEK, Genetisches Institut der FU, Berlin; E. GEBHART, Institut fiir Humangenetik und Anthropologie der Universit~it Erlangen-Ntirnberg, Erlangen; C. FONATSCH,Institut fiir Genetik der Med. Hochschule Hannover, Hannover-Kleefeld; M. BAUCH1NGER AND E. SCHMID, Institut ftir Strahlenbiologie der Universit~t Mfinchen, Mtinchen (West German3, ).
Chromosome analyses after prophylactic and therapeutic application of I N H in man Chromosome analyses were performed in 30 persons treated with isoniazid (INH) for prophylactic reasons and in 37 patients with I N H therapy. The antituber-
4TH ANNUAL MI:.ETIN(;, ItEII)I-LI-IERC,
in 24-hour intervals. The c o n c e n t r a t i o n s were 5, 25 a n d z25 m g / k g b o d y weight. ~', mtrols received o.5 ml salt solution only. The animals were killed a n d the ~-permat~gonial chromosomes were >pread at interval> ,ff 6, I2, 24 a n d 4,~ h after the secured t r e a t m e n t . In mice (4 for each dose a n d test interval) no e n h a n c e m e n t of the chr~,m,~some a b e r r a t i o n rate b e y o n d the >pontaneou> rate was ~bserved at a n v ~f the three doses (z) a n d (e). In Chinese h a m s t e r in one l a b o r a t o r y (z) there wa> also n~, enhanct'ment of the a b e r r a t i o n rate in a n y group of animals, w h e r e a , p r e l i m i n a r y r,>ult~ from a n o t h e r l a b o r a t o r y (3) with 2 animals in each group showed an increase in the numbel of c h r o m a t i d gaps a n d c h r o n m t i d breaks frw I25 m g / k g 24 h after the second t r e a t merit. These results, hmvever, have to be checked again in a n o t h e r e x p e r i m e n t . Long t e r m t r e a t m e n t of mice a n d Chinese h a m s t e r s (3 t r e a t m e n t s per week f~r i2 weeks) with 25 m g / k g in one l a b o r a t o r y (1) did not change the a b e r r a t i o n rate c~mlpared with the controls. B y far the most a b e r r a t i o n s found in these e x p e r i m e n t s were z -2 g a t > per m e t a p h a s e . Cells with lnore t h a n 2 gaps or with break>, fragments and fusi~uls were seldom found.
/~6 ADLER, I.-D., A b t e i l u n g ftir Genetik, Gesellschaft ffir Strahlen- und Umweltfiwschung, N e u h e r b e r g (West G e r m a n y ) , a n d D. MOLLER, D e p a r t m e n t of E x p e r i m e n t a l Toxic~> logy, Ciba-Geigy A. G., Basle (Switzerland).
Chromosome analysis in spermatocytes of mice and Chinese hamsters The s t u d y of meiotic chromosomes after t r e a t i n e n t with isoniazid (INH) consisted of two parts. In the acute s t u d y the doses were 5, 25 or 125 m g / k g given twice 24 h a p a r t . S p e r m a t o c y t e s were s a m p l e d xo a n d z z d a y s after the ~econd t r e a t m e n t , thus representing s p e r m a t o c y t e s t r e a t e d at late D N A synthesis to leptotene. In the chronic s t u d y tim mice were t r e a t e d 3 times per week for I2 weeks with I N H at ~5 mg/kg. The s p e r m a t o c y t e s were s a m p l e d 3 ° d a y s after the last injection, at which time t h e y r e p r e s e n t e d t r e a t e d stein-cell s p e r m a t o g o n i a . F o u r animals per dose a n d control were used, a n d Ioo cells per animal were scored. Diakinesis n l e t a p h a s e I chromosomes were a n a l y z e d for the presence (~f univalents, n m l t i v a l e n t s a n d fragments. M e t a p h a s e l I chromo.~omes were a n a l y z e d for f r a g m e n t s a n d a n e u p M d i e s . In the acute s t u d y with mice a n d Chinese balusters the results d i d not differ from the control values. In the chronic s t u d y with mice, 3 presulned m u l t i v a l e n t s were obs e r v e d : two chain m u l t i v a l e n t s d e r i v e d from one male, a n d one ring n m l t i v a l e n t derived from a n o t h e r male. To verify the result ot the chronic s t u d y the n m n b e r of mice tested as well as the n u m b e r ,~l celN scored per mouse have to be in,'reased.
/~7 ~I(~LLER, D., Basle (Switzerland); A. GRAFE, M a n n h e i m ; H. G. MILTENBURGER, D a l m s t a d t ; G. R(SHRBORN, H e i d e l b e r g : a n d M. SCHULZE-SCHENKING, D a r m s t a d t (W. Germany).
Chromosome analysis of bone m a r r o w and nucleus anomaly test in mammals after t r e a t m e n t with I N H The results of tests for p o t e n t i a l m u t a g e n i c ettects of isoniazid I INH) were
EUROPEAN ENVIRONMENTAL MUTAGEN SOCIETY
257
described. The investigations were carried out independently of one another in five different laboratories. On the one hand, chromosomal analyses were made in cells from the bone marrow of Chinese hamsters, rats and mice. In short-term studies, groups of four animals were treated twice with I N H at doses of 5, 25 and 125 mg/kg at an interval of 24 h. The animals were killed at various times (6, 12, 24 and 48 h) after the second dose. In long-term studies a group of four animals received I N H (25 mg/kg) twice a week for 12 weeks, the animals then being killed six hours after the last dose. The investigators usually examined IOO metaphases from each animal. On the other hand, for the nucleus anomaly test groups of six Chinese hamsters were treated according to the same schedules, IOOO cells from each animal being studied. In addition to the dose groups mentioned, experiments were also conducted on controls. In the cytogenetic investigations carried out in different laboratories, in comparison with the controls no significant increase in the incidence of aberrations was detectable in the majority the animals treated and killed according to the foregoing schedule. Only one investigator found, in animals killed 48 h after the second application, as well as in a repeated experiment in animals killed 6 h after the second dose, an increased number of aberrations. The comparison of these values with the corresponding data of the control group showed a significant difference according to regression analysis (P < o.oi). In the long-term experiments of the nacleus anomaly test only one investigator found a significant increase of aberrations in comparison with tile control (Z2 test, P < o.oi). In the short-term experiments with this test a significant deviation was also observed in one case only, the total number of cells with nuclear anomalies 24 h after the second dose being significantly greater than in the control (ff test, P < o.oi). To sum up, it is clear that the results obtained by the various investigators do not show any consistent pattern. If in single cases an increased number of aberrant metaphases and an increased persentage of nuclear anomalies after the application of I N H was seen by few investigators, the findings were still not even remotely comparable with the results observed after the use of known mutagenic substances. Consequently it would be unwise to draw any definitive conclusions about a mutagenic quality of I N H on the strength of these results. Abbreviation: I N H , isoniacid.
48 OBE, G., B. BEEK, Genetisches Institut der FU, Berlin; E. GEBHART, Institut fiir Humangenetik und Anthropologie der Universit~it Erlangen-Ntirnberg, Erlangen; C. FONATSCH,Institut fiir Genetik der Med. Hochschule Hannover, Hannover-Kleefeld; M. BAUCH1NGER AND E. SCHMID, Institut ftir Strahlenbiologie der Universit~t Mfinchen, Mtinchen (West German3, ).
Chromosome analyses after prophylactic and therapeutic application of I N H in man Chromosome analyses were performed in 30 persons treated with isoniazid (INH) for prophylactic reasons and in 37 patients with I N H therapy. The antituber-
