[Histonet] Isopropanol tissue processing

[Barry R Rittman]

Isopropyl alcohol is miscible with paraffin wax but is only slowly replaced  by it. This technique has been used in the past for delicate tissues and for insects to prevent excessive hardening.
Isopropyl alcohol is a very gentle intermediate agent but while I have not used it in tissue processors, I would suspect that it is not suitable for these as it requires a much longer time for its replacement by the wax. The best method to use for hand processing is to make a "slush" of isopropyl alcohol and paraffin wax and allow to sit at room temperature. Sufficient paraffin wax mixes with the alcohol to allow some to penetrate into the tissues. Best to leave several hours to overnight if possible. This will cut down the time in molten paraffin wax.
Barry

	-----Original Message----- 
	From: histonet-bounces <@t> lists.utsouthwestern.edu on behalf of Gayle Callis 
	Sent: Thu 3/18/2004 10:01 AM 
	To: Histology; Histonet <@t> lists.utsouthwestern.edu 
	Cc: 
	Subject: Re: [Histonet] Isopropanol tissue processing
	
	

	We used isopropanol was used in place of ethyl alcohol as a dehydrant,  but
	never replaced the xylene step just before paraffin with it.  I don't think
	isopropyl alcohol is miscible with paraffin.  My Merck index says isopropyl
	 is miscible with water, alcohol, ether and chloroform (carcinogenic) but
	nothing said about paraffin. 
	
	After isopropyl gradient we cleared with xylene.  You will still need a
	clearant, ie. xylene or one of the xylene substitutes to remove alcohol
	before infiltration with paraffin.  Maybe a better solution is to find a
	better clearant substitute before paraffin.
	
	
	At 11:42 AM 3/18/2004 +1100, you wrote:
	>Hi There
	>
	>Does anyone use Isopropanol in routine overnight parraffin processing
	replacing xylol?? If you are willing could you please supply any protocols
	you may use.
	>Thanks for your help.
	>
	>Frances
	>SDS Pathology
	>Sydney, NSW,Australia
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	Gayle Callis
	MT,HT,HTL(ASCP)
	Research Histopathology Supervisor
	Veterinary Molecular Biology
	Montana State University - Bozeman
	PO Box 173610
	Bozeman MT 59717-3610
	406 994-6367 (lab with voice mail)
	406 994-4303 (FAX)
	
	
	
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