Document Detail

Evidence for placental abnormality as the major cause of mortality in first-trimester somatic cell cloned bovine fetuses.
MedLine Citation:
PMID:  11090450     Owner:  NLM     Status:  MEDLINE    
The production of cloned animals is, at present, an inefficient process. This study focused on the fetal losses that occur between Days 30-90 of gestation. Fetal and placental characteristics were studied from Days 30-90 of gestation using transrectal ultrasonography, maternal pregnancy specific protein b (PSPb) levels, and postslaughter collection of fetal tissue. Pregnancy rates at Day 30 were similar for recipient cows carrying nuclear transfer (NT) and control embryos (45% [54/120] vs. 58% [11/19]), although multiple NT embryos were often transferred into recipients. From Days 30-90, 82% of NT fetuses died, whereas all control pregnancies remained viable. Crown-rump (CR) length was less in those fetuses that were destined to die before Day 90, but no significant difference was found between the CR lengths of NT and control fetuses that survived to Day 90. Maternal PSPb levels at Days 30 and 50 of gestation were not predictive of fetal survival to Day 90. The placentas of six cloned and four control (in vivo or in vitro fertilized) bovine pregnancies were compared between Days 35 and 60 of gestation. Two cloned placentas showed rudimentary development, as indicated by flat, cuboidal trophoblastic epithelium and reduced vascularization, whereas two others possessed a reduced number of barely discernable cotyledonary areas. The remaining two cloned placentas were similar to the controls, although one contained hemorrhagic cotyledons. Poor viability of cloned fetuses during Days 35-60 was associated with either rudimentary or marginal chorioallantoic development. Our findings suggest that future research should focus on factors that promote placental and vascular growth and on fetomaternal interactions that promote placental attachment and villous formation.
J R Hill; R C Burghardt; K Jones; C R Long; C R Looney; T Shin; T E Spencer; J A Thompson; Q A Winger; M E Westhusin
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Biology of reproduction     Volume:  63     ISSN:  0006-3363     ISO Abbreviation:  Biol. Reprod.     Publication Date:  2000 Dec 
Date Detail:
Created Date:  2001-01-23     Completed Date:  2001-01-26     Revised Date:  2009-11-19    
Medline Journal Info:
Nlm Unique ID:  0207224     Medline TA:  Biol Reprod     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  1787-94     Citation Subset:  IM    
Department of Veterinary Physiology and Pharmacology, Texas A&M University, College Station, Texas 77843 USA.
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MeSH Terms
Aspartic Acid Endopeptidases / biosynthesis
Cell Line
Cloning, Organism
Fetal Death / etiology*,  ultrasonography
Fetal Monitoring
Fetal Viability / physiology
Fetus / physiology*
Placenta / abnormalities*,  pathology
Pregnancy Proteins / biosynthesis
Pregnancy Trimester, First
Survival Analysis
Zygote Intrafallopian Transfer
Grant Support
Reg. No./Substance:
0/Pregnancy Proteins; EC 3.4.23.-/Aspartic Acid Endopeptidases; EC 3.4.23.-/pregnancy-associated glycoprotein 1

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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