title: Chronology of labyrinthitis ossificans induced by Streptococcus pneumoniae meningitis.
abstract: OBJECTIVE
  Labyrinthitis ossificans consists of novel osteogenesis that fills the normally patent cochlear and vestibular lumen as an end-stage sequelae to various pathologies. This study was designed to establish the sequence of events and chronology of the osteoneogenesis and calcification.
  
  
  METHODS
  A prospective randomized double-blind study.
  
  
  METHODS
  By using serial application of different colored fluorochromes, which deposit in newly forming bone, the timing of bone deposition and bone remodeling can be established. Labyrinthitis ossificans was induced in six groups (n = 5) of gerbils by an intrathecal injection of live Streptococcus pneumoniae. Group 1 received no fluorochrome labels, group 2 received one label, group 3 received three labels, and groups 4, 5, and 6 received four labels. The temporal bones were harvested after 2 weeks (group 1), 1 month (group 2), 3 months (group 3), 4 months (group 4), 6 months (group 5), and 12 months (group 6).
  
  
  RESULTS
  Sixteen of the 25 animals that received labels developed ossification, demonstrated with fluorescent microscopy. In the animals that developed labyrinthitis ossificans, newly formed disorganized bone began calcifying as early as 3 weeks (label 1) after S. pneumoniae injection. Osteoneogenesis continued as evidenced by the presence of the other labels when first applied at 6 weeks (label 2), and 10 weeks (label 3). Ossification, calcification, and remodeling proceeded through a 12-month course, wherein a reduction of labels was present at 6 months and total disappearance by 12 months.
  
  
  CONCLUSIONS
  The use of fluorescent stains in this animal model provides a means to establish a timeline of the ossification seen in labyrinthitis ossificans.
authors.affiliation: School of Medicine, University of California, Davis, USA.
authors.forename: V
authors.initials: V
authors.lastname: Nabili
authors.forename: H A
authors.initials: HA
authors.lastname: Brodie
authors.forename: N I
authors.initials: NI
authors.lastname: Neverov
authors.forename: S P
authors.initials: SP
authors.lastname: Tinling
mesh_terms: D000818:Animals; D003051:Cochlea / Q000382:microbiology / Q000473:pathology / Q000601:surgery; D003054:Cochlear Implants; D003638:Deafness / Q000382:microbiology / Q000473:pathology / Q000601:surgery; D004195:Disease Models, Animal; D005456:Fluorescent Dyes; D005849:Gerbillinae; D007762:Labyrinthitis / Q000382:microbiology* / Q000473:pathology; D008297:Male; D008586:Meningitis, Pneumococcal / Q000150:complications* / Q000473:pathology; D009999:Ossification, Heterotopic / Q000382:microbiology* / Q000473:pathology
chemical_list: D005456:Fluorescent Dyes