title: Empirical Derivation of Correction Factors for Human Spiral Ganglion Cell Nucleus and Nucleolus Count Units.
abstract: OBJECTIVE
  Profile count method for estimating cell number in sectioned tissue applies a correction factor for double count (resulting from transection during sectioning) of count units selected to represent the cell. For human spiral ganglion cell counts, we attempted to address apparent confusion between published correction factors for nucleus and nucleolus count units that are identical despite the role of count unit diameter in a commonly used correction factor formula.
  
  
  METHODS
  We examined a portion of human cochlea to empirically derive correction factors for the 2 count units, using 3-dimensional reconstruction software to identify double counts.
  
  
  METHODS
  The Neurotology and House Histological Temporal Bone Laboratory at University of California at Los Angeles.
  
  
  METHODS
  Using a fully sectioned and stained human temporal bone, we identified and generated digital images of sections of the modiolar region of the lower first turn of cochlea, identified count units with a light microscope, labeled them on corresponding digital sections, and used 3-dimensional reconstruction software to identify double-counted count units.
  
  
  RESULTS
  For 25 consecutive sections, we determined that double-count correction factors for nucleus count unit (0.91) and nucleolus count unit (0.92) matched the published factors. We discovered that nuclei and, therefore, spiral ganglion cells were undercounted by 6.3% when using nucleolus count units.
  
  
  CONCLUSIONS
  We determined that correction factors for count units must include an element for undercounting spiral ganglion cells as well as the double-count element. We recommend a correction factor of 0.91 for the nucleus count unit and 0.98 for the nucleolus count unit when using 20-µm sections.
authors.affiliation: Pasadena, California, USA.
authors.forename: Mark E
authors.initials: ME
authors.lastname: Robert
authors.affiliation: Neurotology and House Histological Temporal Bone Laboratory at University of California, Los Angeles, California, USA FLinthicum@mednet.ucla.edu.
authors.forename: Fred H
authors.initials: FH
authors.lastname: Linthicum
mesh_terms: D002452:Cell Count; D022003:Cell Nucleus Structures; D006801:Humans; D008875:Middle Aged; D013136:Spiral Ganglion / Q000166:cytology* / Q000648:ultrastructure
keywords: count unit; human spiral ganglion cell; population estimate; profile count correction factor