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
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
