When 3-4 segments of the chick lumbosacral neural tube are reversed in the anterior-posterior axis at stage 15 (embryonic day 2.5), the spinal cord develops with a reversed organization of motoneurons projecting to individual muscles in the limb (C. Lance-Jones and L. Landmesser (1980) J. Physiol. 302, 581-602). This finding indicated that motoneuron precursors or components of their local envi...

Abnormal folate one-carbon metabolism (FOCM) is implicated in neural tube defects (NTDs), severe malformations of the nervous system. MTHFR mediates unidirectional transfer of methyl groups from the folate cycle to the methionine cycle and, therefore, represents a key nexus in partitioning one-carbon units between FOCM functional outputs. Methionine cycle inhibitors prevent neural tube closure ...

Over a two-year period, 3479 pregnant women in the Kings' Lynn Health District were screened for neural tube defects by estimation of maternal serum alpha-fetoprotein. Most pregnancies were scanned by sonar for fetal maturity. Eight women had fetuses with open neural tube defects; four with anencephaly were associated with very high alpha-fetoprotein values. Of the four with open neural tube de...

TIn the US, one in 1000 births is affected by neural tube [4] defects (NTD). A neural tube [4] defect is a birth defect involving the malformation of body features associated with the brain and spinal cord. An NTD originates from and is characterized by incomplete closure of the neural tube [4], which is an organizer [5] and precursor of the central nervous system [6]. In humans [7], incomplete...

Cell pattern in the ventral neural tube is organized by Sonic hedgehog (Shh) secreted by floor plate cells. To assay the range of direct Shh action, we developed a general method for blocking transduction of Hedgehog (Hh) signals through ectopic expression of a deleted form of the Hh receptor Patched (Ptc), termed Ptc(Deltaloop2). We validated this method in Drosophila and used mouse Ptc1(Delta...

THE aetiology of anencephaly and/or spina bifida (neural tube defects) is still obscure. Most investigators are now agreed on a multifactorial causation with an important genetic factor and a substantial environmental component. The genetic factor is probably polygenic, but the mechanism by which it acts remains unknown. Recently, drugs that stimulate ovulation, particularly clomiphene, have be...

The low-density lipoprotein (LDL) receptor-related protein 2 (LRP2) is a multifunctional cell-surface receptor expressed in the embryonic neuroepithelium. Loss of LRP2 in the developing murine central nervous system (CNS) causes impaired closure of the rostral neural tube at embryonic stage (E) 9.0. Similar neural tube defects (NTDs) have previously been attributed to impaired folate metabolism...

TIn the US, one in 1000 births is affected by neural tube [4] defects (NTD). A neural tube [4] defect is a birth defect involving the malformation of body features associated with the brain and spinal cord. An NTD originates from and is characterized by incomplete closure of the neural tube [4], which is an organizer [5] and precursor of the central nervous system [6]. In humans [7], incomplete...

OBJECTIVE To determine trends in total prevalence of neural tube defects in South Australia during 1966-91, the impact of prenatal diagnosis on birth prevalence, and the effectiveness of prenatal screening for neural tube defects in 1986-91. DESIGN All births and terminations of pregnancy affected by neural tube defects and information on prenatal screening were ascertained from multiple sour...

The Pax genes containing a complete paired-type homeobox are expressed in restricted dorsoventral domains of the undifferentiated neuroepithelium. Their expression respond to signals that pattern the neural tube and which emanate from the notochord, floor plate and overlying ectoderm. In order to determine whether the dorsally restricted Pax3 gene can influence the fate of cells within the neur...