PMC

Small fibers are better detectable with electron microscopy than with high resolution light microscopy.
High resolution light microscopy image (A), a magnified image of image A(A′), and electron microscopy image of the region highlighted in the red/black rectangle shown in A/A′ images (B) of a regenerated nerve. Some fibers that are not detectable in light microscopy analysis are easily detectable in electron microscopy analysis (highlighted by three red asterisks). Bar: A, 20 μm; B, 2 μm.

The use of different housekeeping genes affects normalized relative quantification.
The normalized relative quantification (NRQ) of the expression of two genes highly regulated following rat median nerve crush injury (axonotmesis) is shown. Myelin basic protein (MBP, panel A) and Neuregulin 1 (NRG1, panel B) were analysed 1, 7 and 28 days after nerve injury, (n = 3 for each time point) on RNA extracted from the nerve segment distal to the lesion site.
Gene expression was normalized to 6 commonly used housekeeping genes (TBP: TATA box binding protein; UBC: ubiquitin C; GAPDH: glyceraldehyde-3-phosphate dehydrogenase; NSE: neuron specific enolase; HPRT: hypoxanthine guanine phosphoribosyl-transferase; 18S: 18S ribosomal RNA) and 4 highly stable newly identified housekeeping genes (RICTOR: RPTOR Independent Companion Of MTOR, Complex 2; ANKRD27: ankyrin repeat domain 27; Mrpl10: mitochondrial ribosomal protein L10; Ubxn11: UBX domain protein 11).
This figure shows how the gene expression pattern changes when different housekeeping genes are used for normalization and the gene expression pattern after normalization to the geometric mean of two highly stable newly identified housekeeping genes, Rictor and Ankrd27 (black line).