The innovative safe fixative for histology, histopathology, and immunohistochemistry techniques: "pilot study using shellac alcoholic solution fixative".

The concerns over health and workplace hazards of formalin fixative, joined to its cross-linking of molecular groups that results in suboptimal immunohistochemistry, led us to search for an innovative safe fixative. Shellaci san atural material which is used as ap reserva- tive in foods and pharmaceutical industries. This study was undertaken to evaluate the fixation adequacy and staining quality of histopathological specimens fixedin the " shellacalcoholic sol- ution" (SAS), and also to determine the validity of immunohistochemical staining of SAS- fixedmaterial in comparison to those fixedin formalin. Fresh samples from 26 cases from various human tissues were collected at the frozen section room of King Abdulaziz University Hospital, and fixedin SAS fixativeor in neutral buffered formaldehyde (NBF) for 12, 18, 24, and 48 h, and processed for paraffin sectioning. Deparaffinized sections were stained with hematoxylin and eosin (H&E) and immunostained for different antigens. The tissues fixedin SAS for >18 h showed best staining quality of H&E comparable to NBF- fixedtissues. Comparison of the immu- nohistochemical staining of different tissues yielded nearly equivalent readings with good posi- tive nuclear staining quality in both fixatives. These findings support the fixation and preservation adequacy of SAS. Furthermore, it was concluded that the good staining quality obtained with SAS- fixedtissues, which was more or less comparable with the quality obtained with the formalin fixedtissues, supports the validity of this new solution as a good innovative fix- ative. Microsc. Res. Tech. 00:000-000, 2014. V C 2014 Wiley Periodicals, Inc.