First-time users are encouraged to contact Core staff to discuss their experiments for advice on tissue collection, fixation, embedding, and stains.
- Supplies (*free to MPC users)
- *10% neutral buffered formalin in 8 oz. specimen cups (NBF, ThermoFisher, 23-032-060)
- *Specimen plastic containers (all sizes, recycled)
- *Cassettes (biopsy and regular sizes)
- *Biopsy sponges and bags for use in regular cassettes
- Consumables for using the microtome and cryostat can be purchased.
- Paraffin slides- trim, process, embed, section, stain, microscopy, analyze
- Frozen slides- sucrose cryoprotection for fixed frozens, embedding for fresh or fixed frozen blocks, section, stain, microscopy, analyze
- DNAse/RNAse free slide sectioning
- H&E and Special stains: PAS/PASD, Oil red O (frozen only), Van Gieson’s, Congo Red, Masson’s Trichrome, Luxol Blue, others.
Paraffin processing is performed using automatic processors (VIP6, Leica) with graded ethanols (70-100%) and xylene. Fixations are performed and stopped in one’s own lab. Standard programs are based on species, tissue size, and fat content. Customized programs can be set up to your specifications.
Paraffin samples are routinely sectioned at 4 um thickness unless another thickness requested.
Several different levels of sectioning are available for paraffin and frozen tissues (adapted from Gladstone Histology Core, UCSF):
- Simple sectioning- block is trimmed to full face and 1 unstained section placed on a slide. The total number of slides needed depends on what you need ie H&E, IHC, or only unstained slides.
- Levels – unstained sections are placed on a slide, then a certain distance (um) is discarded and then another section is placed on a slide. Indicate the level’s distance you want on the submission form. Levels are often requested when a large amount of tissue is to be surveyed and every section doesn’t need to be kept. Don’t forget to get extra slides as once a level is cut through, there is no retrieving it.
- Special sectioning to view a particular area of interest, e.g. islet transplant, lesion found at necropsy, hippocampus in coronal or sagittal brain sections. These requests require orienting and trimming the block before placing in the cassette then sectioning to the area of interest. Sections are placed either serially or on adjacent slides:
- Serials on the same slide– serial sections in ribbons of paraffin or from adjacent frozen sections are placed on the same slide. Each section is a continuation of the last one. This technique is good for surveying special area of interest and to stain all the sections with the same stain.
- Serials across adjacent slides – Where adjacent sections are placed on separate slides across a set, each slide in the set is then representative of the whole area of interest. This is ideal when you want to perform multiple probes/antibodies / downstream techniques on the same sample, in series, so each section needs to be on its own slide.
Personalized services are available such as working with a histotechnician to identify structures of special interest while the tissue is being sectioned or for developing a new procedure. Contact us for more information.