Special stains. Based on the re- sults of the general staining, selected sites and cellular components shall be further evaluated by use of specific techniques. If H&E screening does not provide such information, a battery of stains shall be used to assess the fol- lowing components in all appropriate required samples: Neuronal body (e.g., Xxxxxxxx’x gallocyanin), axon (e.g., Xxxxxx’x Luxol Fast Blue), and neurofibrils (e.g., Bielchosky). In addi- tion, nerve fiber teasing shall be used. A section of normal tissue shall be in- cluded in each staining to assure that adequate staining has occurred. Any changes shall be noted and representa- tive photographs shall be taken. If xx- xxxxx are observed, the special tech- niques shall be repeated in the next lower treatment group until no further lesions are detectable.
Special stains. B a sed o n t h e r e- s u l t s of t h e ge n e r a l s t a i n i n g, selec t ed s i t es a n d cell u l a r co m po n e n t s s h a ll be fur t h e r ev a l u a t ed b y u se of specific t ec hn iq u es. If H& E sc r ee n i n g does n o t p r ovide s u c h i nfo r m a t io n , a b a tt e ry of s t a i n s s h a ll be u sed t o a ssess t h e fol- lowi n g co m po n e n t s i n a ll a pp r op r i a t e r eq u i r ed s a m ples: Ne ur o n a l bod y ( e. g., E i n a r so n’s g a lloc y a n i n), a xo n ( e. g., Kl u ve r’s L u xol F a s t Bl u e), a n d n e ur ofib r il s ( e. g., Bielc h os k y). I n a ddi- t io n , n e r ve fibe r t e a s i n g s h a ll be u sed. A sec t io n of n o r m a l t iss u e s h a ll be i n- cl u ded i n e a c h s t a i n i n g t o a ss ur e t h a t a deq u a t e s t a i n i n g h a s occ urr ed. A ny c h a n ges s h a ll be n o t ed a n d r ep r ese n t a- t ive p h o t og r a p h s s h a ll be t a k e n . If le- s io n s a r e obse r ved, t h e speci a l t ec h- n iq u es s h a ll be r epe a t ed i n t h e n ex t lowe r t r e a t m e n t g r o u p un t il n o fur t h e r lesio n s a r e de t ec t a ble.
