title: Histologic sectioning produces TUNEL reactivity. A potential cause of false-positive staining.
abstract: OBJECTIVE
  To determine if the DNA strand breaks caused by tissue sectioning result in terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end-labeling (TUNEL) reactivity.
  
  
  METHODS
  The incidence and location of TUNEL-positive nuclei were determined in 5- and 15-micron sections of human stomach. Five- and 15-micron sections of tonsil were stained as a positive control.
  
  
  RESULTS
  In 5-micron gastric sections, 69% of nuclei were labeled; in 15-micron sections, only 30% were labeled. In the latter sections, almost all labeled nuclei were located at the cut surface of sections. Labeled nuclei did not have apoptotic morphology. Apototic bodies and tingible body macrophages were labeled throughout 15-micron sections of tonsil.
  
  
  CONCLUSIONS
  Tissue sectioning creates TUNEL reactivity. The morphologic findings on routine stains should be considered the gold standard for the detection of apoptosis on tissue sections.
authors.affiliation: Department of Pathology, Louisiana State University School of Medicine, New Orleans, LA 70112, USA.
authors.forename: G D
authors.initials: GD
authors.lastname: Sloop
authors.forename: J C
authors.initials: JC
authors.lastname: Roa
authors.forename: A G
authors.initials: AG
authors.lastname: Delgado
authors.forename: J T
authors.initials: JT
authors.lastname: Balart
authors.forename: M O
authors.initials: MO
authors.lastname: Hines
authors.forename: J M
authors.initials: JM
authors.lastname: Hill
mesh_terms: D016477:Artifacts; D002452:Cell Count; D002467:Cell Nucleus / Q000235:genetics*; D004247:DNA / Q000032:analysis*; D053938:DNA Fragmentation; D005189:False Positive Reactions; D006801:Humans; D020287:In Situ Nick-End Labeling; D008867:Microtomy; D014066:Palatine Tonsil / Q000166:cytology*; D013270:Stomach / Q000166:cytology*
chemical_list: D004247:DNA