title: Design-based stereological estimation of the total number of cardiac myocytes in histological sections.
abstract: BACKGROUND
  Counting the total number of cardiac myocytes has not previously been possible in ordinary histological sections using light microscopy (LM) due to difficulties in defining the myocyte borders properly.
  
  
  OBJECTIVE
  To describe a method by which the total number of cardiac myocytes is estimated in LM sections using design-based stereology.
  
  
  METHODS
  From formalin-fixed left rat ventricles (LV) isotropic uniformly random sections were cut. The total number of myocyte nuclei per LV was estimated using the optical disector. Two-microm-thick serial paraffin sections were stained with antibodies against cadherin and type IV collagen to visualise the intercalated discs and the myocyte membranes, respectively. Using the physical disector in "local vertical windows" of the serial sections, the average number of nuclei per myocyte was estimated.
  
  
  RESULTS
  The total number of myocyte nuclei in LV was 34.1 x 10(6) (0.08) (mean (coefficient of variation)), and the mean number of nuclei per myocyte 1.85 (0.03). Combining these estimates the total number of myocytes in LV was calculated to be 18.5 x 10(6) (0.09).
  
  
  CONCLUSIONS
  This new method is applicable to a range of experiments focusing on myocyte proliferation and death.
authors.affiliation: Department of Connective Tissue Biology, Institute of Anatomy, , Building 233 University of Aarhus, 8000, Aarhus C, Denmark. mb@ana.au.dk
authors.forename: A
authors.initials: A
authors.lastname: Brüel
authors.forename: J R
authors.initials: JR
authors.lastname: Nyengaard
mesh_terms: D000818:Animals; D002452:Cell Count; D002467:Cell Nucleus / Q000648:ultrastructure; D005260:Female; D032383:Myocytes, Cardiac / Q000166:cytology* / Q000648:ultrastructure; D051381:Rats; D017208:Rats, Wistar