Timothy Graeme Overton

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The yolk sac and aorto-gonad-mesonephros region are well recognized as the principal sites of hematopoiesis in the developing embryo, and the liver is the principal site of hematopoiesis in the fetus. However, little is known about circulating hematopoietic stem and progenitor cells in early fetal life. We investigated the number and characteristics of(More)
OBJECTIVES Our purpose was to test the hypothesis that reverse transcriptase-polymerase chain reaction for fetal messenger ribonucleic acid in maternal blood is more sensitive than polymerase chain reaction from genomic deoxyribonucleic acid in prenatal determination of fetal RhD blood type. STUDY DESIGN Fetal nucleated erythrocytes in peripheral blood(More)
OBJECTIVES Our purpose was to describe the fetal loss rate and platelet dynamics in fetal alloimmune thrombocytopenia managed by serial platelet transfusions. METHODS Retrospective analysis over 10 years of consecutive pregnancies affected by fetal alloimmune thrombocytopenia requiring in utero platelet transfusions. RESULTS There were 2 perinatal(More)
OBJECTIVE We sought to identify clinical factors at diagnosis that predict outcome in twin-twin transfusion syndrome. STUDY DESIGN In this retrospective series 23 patients with twin-twin transfusion syndrome were seen in a tertiary referral fetal medicine center over a 3-year period. Ten antenatal factors were assessed to determine their ability to(More)
OBJECTIVE Monoamniotic twinning occurs in only 1% of twin pregnancies, but carries a high perinatal mortality rate. Early and reliable diagnosis is essential if attempts are to be made to reduce the complication rate. We report color Doppler demonstration of cord entanglement in the first trimester, which is diagnostic of monoamnionicity. METHODS Two(More)
OBJECTIVE Our purpose was to determine the accuracy of RhD typing by use of amniocytes obtained at amniocentesis in RhD-negative women. STUDY DESIGN One hundred thirty-five RhD-negative women undergoing amniocentesis for management of suspected alloimmunization (n = 95) or routine second-trimester cytogenetic indications (n = 40) were studied. Amniocytes(More)
OBJECTIVE Our purpose was to devise diagnostic test(s) that determine fetal KEL1 and KEL2 genotypes. STUDY DESIGN KEL1 and KEL2 polymorphisms are due to a single C to T base substitution at nucleotide 698 of exon 6 of KEL. This allowed us to develop two polymerase chain reaction tests that distinguish KEL1/1 and KEL2/2 homozygotes and KEL1/2(More)
BACKGROUND The birth prevalence of gastroschisis is increasing worldwide, yet little evidence exists concerning the optimal monitoring strategies after diagnosis. The aim of this study was to describe the U.K. prevalence, antenatal management and outcomes of affected pregnancies. METHODS Cases were identified throughout the U.K. between October 2006 and(More)
DNA analysis of blood is conventionally performed on cells - plasma and serum are discarded. Free DNA has been demonstrated in serum in cancer and autoimmune disorders and in pregnancy. We investigated possible noninvasive prenatal diagnosis using fetal DNA from maternal plasma and serum in pregnancy. Fetal gender was determined by PCR on DNA from maternal(More)