04.04.17 // the past week/current week so far has just been non-stop. i’m super tired, but really happy with how productive i’ve been! pictured clockwise from top left: treating breast cancer cells with increasing concentrations of curcumin, hematoxylin and eosin staining of bone with breast cancer bone metastasis, running 7 western blots at once (yes it was kinda chaotic), and a close-up of breast cancer cells during an MTT assay which measures cell proliferation through the production of purple formazan by active mitochondria.


The most routine stain done in the Histology lab is the Hematoxylin & Eosin (H&E) stain. The hematoxylin stains the nuclei of the tissue a violet color while the eosin stains elements of the cytoplasm (collagen, muscle, RBC’s, etc.) various shades of pink. Here we have an ovary, skin, placenta and thyroid looking very different in the shades of colors I have described even though the same stain was performed.

A few amusing things from today’s lectures:

1) Hematoxylin & eosin stain turns tissues the most amusing shades of pink and purple… a shade of both colors that one typically only sees in *ahem*… toys. (Seriously. Go look up “H&E stain” on Google Images. You’ll never look at adrenal zona fasciculata the same way.)

2) “Tobaxes” as a portmanteau for tobacco taxes.

3) “Everything Comes Down to Poo” being played in class as a commentary on rising health care costs. Which is entirely accurate.

The ependyma is made up of ependymal cells, ependymocytes. These epithelial-like cells line the CSF-filled ventricles in the brain and the central canal of the spinal cord. The cells are ciliated simple cuboidal epithelium-like cells. Their apical surfaces are covered in a layer of cilia, which circulate CSF around the CNS. Their apical surfaces are also covered with microvilli, which absorb CSF. Ependymal cells are a type of glial cell and are also CSF producing cells. Within the ventricles of the brain, a population of modified ependymal cells and capillaries together form a system called the choroid plexus, which produces the CSF.

Modified tight junctions between ependymal cells control fluid release across the epithelium. This release allows free exchange between CSF and nervous tissue of brain and spinal cord. This is why sampling of CSF (e.g. through a “spinal tap”) gives one a window to the CNS.

Image: Photomicrograph of hematoxylin stained section of normal ependymal cells at 400x magnification.