In 1995 the RITA Group has published the paper "RITA – Registry of Industrial Toxicology Animal-data – Guides for organ sampling and trimming in rats –" (Exp Toxic Pathol 47: 247–266, 1995) in order to standardize the organ sampling and trimming procedures in all laboratories. An electronic version is available in the Internet with kind permission of Urban & Fischer Verlag.

In close collaboration between scientists of the RITA Group (Registry of Industrial Toxicology Animal-data) and of the NACAD Group (North American Control Animal Database) the guides were revised and also extended to mouse tissues, resulting in a series of 3 articles: Ruehl-Fehlert C, Kittel B, Morawietz G, Deslex P, Keenan C, Mahrt CR, Nolte T, Robinson M, Stuart BP, Deschl U (2003) Revised guides for organ sampling and trimming in rats and mice – Part 1. A joint publication of the RITA and NACAD groups. Exp Toxic Pathol 55: 91–106 Kittel B, Ruehl-Fehlert C, Morawietz G, Klapwijk J, Elwell MR, Lenz B, O'Sullivan MG, Roth DR, Wadsworth PF (2004) Revised guides for organ sampling and trimming in rats and mice – Part 2. A joint publication of the RITA and NACAD groups. Exp Toxic Pathol 55: 413–431 Morawietz G, Ruehl-Fehlert C, Kittel B, Bube A, Keane K, Halm S, Heuser A, Hellmann J (2004) Revised guides for organ sampling and trimming in rats and mice – Part 3. A joint publication of the RITA and NACAD groups. Exp Toxic Pathol 55: 433–449 The optimum localization for tissue preparation, the sample size, the direction of sectioning and the number of sections to be prepared is described organ by organ. These descriptions are illustrated for each organ by a schematic drawing and a macro-photograph showing the plane of section as well as a low power view of the H&E stained slide demonstrating the optimum "end-product". A few examples taken from the tongue are shown in a reduced size. It is anticipated that these trimming guides will be made available on the Internet in a similar way as the first version.