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<HTML> <HEAD> <TITLE>Re: [Annelida] formol vs RCL2</TITLE> </HEAD> <BODY> Dear All, My first thoughts about RCL2, a possible substitute for formol that seems to be successfully applied in medical histopathology. It seems that looking at the patent that RCL2 is 70% EtOH with the addition of acetic acid (likely added for better/stronger fixation) and trehalose, a disaccharide that is part of plants and involved in the protection against dehydration. The interesting thing about this fixative/preservative is that the acidic alcohol its dehydration properties are possibly neutralized by the trehalose which apparently makes the alcohol mixture not only usable for preserving/analysing DNA and (functional) proteins but also provide good morphology, which is a problem with plain ethanol 75% (shrinkage and cell collapse). I am curious about the pH and its stability. Also has to be remarked that it is like ethanol still a hazardous compound with regard to flammability. Other alternatives for formalin might be found in DMDM-hydantoin a safe alternative for formalin used primarily in shampoos and hand soaps. More info about DMDMH: van Dam, Andries J. 2003. DMDM-Hydantoin: The promising Result of a Search for an Alternative in Fluid Preservation of Biological Specimens. Collection Forum, 18(1-2):104-115. Molin, Daniël G.M. and Andries J. Van Dam. 2006. A Preservation Method Supporting Multipurpose Analysis of Long-stored Samples. Cell Preservation Technology. March 1, 2006, 4(1): 46-50.  -- Andries J. van Dam, conservator Co-ordinator ICOM-CC Working Group Natural History Collections <a href="http://icom-cc.org/WG/NaturalHistoryCollections">http://icom-cc.org/WG/NaturalHistoryCollections</a> Administrator WG-interactions, the official forum site of ICOM-CC: <a href="http://icom-cc-wg.phpbb24.com">http://icom-cc-wg.phpbb24.com</a> (launch January 2008) New address: Museum of Anatomy Leiden University Medical Center Postal zone T7-P P.O. Box 9600 2300 RC Leiden The Netherlands tel: +31 (0)71 526 9581 fax: +31 (0)71 526 8275 E-mail: A.J.van_Dam@lumc.nl Visiting address: Hippocratespad 21, building 3 From: annelida-bounces@oat.bio.indiana.edu on behalf of Geoff Read Sent: Wed 3/19/2008 10:01 PM To: annelida mailing list Subject: Re: [Annelida] formol vs RCL2 >>> On 20/03/2008 at 4:27 a.m., Stanislas DUBOIS <Stanislas.Dubois@ifremer.fr> > For safety and health reasons, formaldehyde (formol) will be soon > prohibited (at least in Europe .. I'm not sure for other countries). > That might be problematic for specimen preservation since, as many of > you I guess, I used to fix collected polychaetes from benthic samples in > formaldehyde.  I just learned that RCL2 might be of great interest to > substitute for formol.  Does anyone already experience this surrogate > formol or does anyone has any information to share with me, as far as > fixation quality of tissues for IDs (I'm not talking of doing any > molecular analysis), preservation of pigments etc.... Thanks for the news Stan. My guess is that RCL2 has yet to spread far in the medical world, and even less into general use. The formulation is not public but contains acetic acid (vinegar). Perhaps someone can find out how much more expensive it is compared to formalin, bearing in mind that it's the medical/pathology market that they're selling it into. Those interested can check the company web page: <a href="http://www.alphelys.com/site/us/pFF_FixateurSansFormol.htm">http://www.alphelys.com/site/us/pFF_FixateurSansFormol.htm</a> The paper of 2006 by Delfour et al that they cite,  is available full text at pubmed "RCL2, a New Fixative, Preserves Morphology and Nucleic Acid Integrity in Paraffin-Embedded Breast Carcinoma and Microdissected Breast Tumor Cells" <a href="http://www.pubmedcentral.nih.gov/">http://www.pubmedcentral.nih.gov/</a> just search for rcl2. Yes, there is a general understandable reluctance of field workers to use formalin these days. I dislike working with it also. But, I find the usual substitute - ethanol - can result in rigid brittle specimens that are very inferior to those formalin-fixed for morphology and identification, or in disintegrating rubbish in bulk, sediment-laden samples. Geoff --  Geoff Read <g.read@niwa.co.nz>    <a href="http://www.annelida.net/">http://www.annelida.net/</a>   <a href="http://www.niwascience.co.nz/ncabb/">http://www.niwascience.co.nz/ncabb/</a> _______________________________________________ Annelida mailing list Post: Annelida@net.bio.net Help/archive: <a href="http://www.bio.net/biomail/listinfo/annelida">http://www.bio.net/biomail/listinfo/annelida</a> Resources: <a href="http://www.annelida.net">http://www.annelida.net</a> <a href="http://www.annelida.net/"><http://www.annelida.net/></a> </BODY> </HTML>

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