title: An experimental study on the developmental malformations of the trisomy 18 NMRI mice.
abstract: OBJECTIVE
  To study the incidence of trisomy 18 in NMRI mice and its developmental malformations.
  
  
  METHODS
  Sixty female NMRI mice and 11 male mice with the Rb(2.18) 6 Rma and Rb (1 +/-18) 10 Rma chromosomes were used. On the gestational days 16 and 17, the pregnant mice were randomly killed by cervical dislocation. A total of 823 implants were gained from 60 litters; they comprised 569 living foetuses, and chromosomal examination was performed in the generated living foetuses. Gross morphological study was performed in all living fotuses.
  
  
  RESULTS
  Ninety-five foetuses were identified as trisomic foetuses in all of 569 living foetuses. Among them, there were 68 trisomy 18 NMRI mice with cleft palate. Gross morphological study showed that trisomy 18 foetuses had significant body flexion. Some cases of trisomy 18 showed shortened limbs, oedematous body or exencephaly as additional symptoms.
  
  
  CONCLUSIONS
  Developmental malformations in trisomy 18 NMRI mice showed a seried of abnormalities; they had not only the underdeveloped body weight, but also the highter incidence of congenital cleft palate.
authors.affiliation: Department Oral and Maxillofacial Surgery, School of Stamotology, Peking University, Beijing, 100081 P.R.China. CZGJRP@ihw.com.cn
authors.forename: Z
authors.initials: Z
authors.lastname: Cai
authors.forename: H
authors.initials: H
authors.lastname: von Domarus
authors.forename: E
authors.initials: E
authors.lastname: Engel
mesh_terms: D000818:Animals; D002887:Chromosomes, Human, Pair 18; D002972:Cleft Palate / Q000453:epidemiology; D000013:Congenital Abnormalities / Q000453:epidemiology*; D005260:Female; D008297:Male; D051379:Mice; D011247:Pregnancy; D014314:Trisomy