Maternal and Cord Blood Manganese Concentrations and Early Childhood Neurodevelopment among Residents near a Mining-Impacted Superfund Site.

Background: Environmental manganese exposure has been associated with adverse neurodevelopmental outcomes among school-aged children; yet, few studies have evaluated prenatal exposure.

Objectives: Our study examines associations between prenatal manganese concentrations and placental transfer of manganese with neurodevelopment in 224 2-y-old children residing near the Tar Creek Superfund Site.

Methods: We collected maternal and cord blood at delivery, measured manganese using inductively coupled plasma mass spectrometry, and assessed neurodevelopment using the Bayley Scales of Infant Development-II.

Prenatal Arsenic Exposure and Birth Outcomes among a Population Residing near a Mining-Related Superfund Site.

Background: Limited epidemiologic data exist on prenatal arsenic exposure and fetal growth, particularly in the context of co-exposure to other toxic metals.

Objective: We examined whether prenatal arsenic exposure predicts birth outcomes among a rural U.S.

De novo genetic variation revealed in somatic sectors of single Arabidopsis plants.

Concern over the tremendous loss of genetic diversity among many of our most important crops has prompted major efforts to preserve seed stocks derived from cultivated species and their wild relatives.  Arabidopsis thaliana propagates mainly by self-fertilizing, and therefore, like many crop plants, theoretically has a limited potential for producing genetically diverse offspring. Despite this, inbreeding has persisted in Arabidopsis for over a million years suggesting that some underlying adaptive mechanism buffers the deleterious consequences of this reproductive strategy.

Arabidopsis eIF5A3 influences growth and the response to osmotic and nutrient stress.

AteIF5A3, one of three genes encoding eukaryotic translation initiation factor 5A (eIF5A) in Arabidopsis thaliana, and corresponding genes PdeIF5A3 from Populus deltoides (eastern cottonwood) and SleIF5A4 from Solanum lycopersicum (tomato) were constitutively over-expressed in A. thaliana. The resultant transgenic plants exhibited enhanced vegetative and reproductive growth.

Maternal arsenic exposure and impaired glucose tolerance during pregnancy.

Background: Accumulating evidence has shown an increased risk of type 2 diabetes in general populations exposed to arsenic, but little is known about exposures during pregnancy and the association with gestational diabetes (GD).

Objectives: We studied 532 women living proximate to the Tar Creek Superfund Site to investigate whether arsenic exposure is associated with impaired glucose tolerance during pregnancy.

Methods: Blood glucose was measured between 24 and 28 weeks gestation after a 1-hr oral glucose tolerance test (GTT) as part of routine prenatal care.

Variants in iron metabolism genes predict higher blood lead levels in young children.

Background: Given the association between iron deficiency and lead absorption, we hypothesized that variants in iron metabolism genes would predict higher blood lead levels in young children.

Objective: We examined the association between common missense variants in the hemochromatosis (HFE) and transferrin (TF) genes and blood lead levels in 422 Mexican children.

Methods: Archived umbilical cord blood samples were genotyped for HFE (H63D and C282Y) and TF (P570S) variants.

Eukaryotic translation initiation factor 5A is involved in pathogen-induced cell death and development of disease symptoms in Arabidopsis.

Eukaryotic translation initiation factor 5A (eIF5A) is a highly conserved protein found in all eukaryotic kingdoms. This study demonstrates that plant eIF5A is involved in the development of disease symptoms induced by a common necrotrophic bacterial phytopathogen. Specifically, AteIF5A-2, one of the three eIF5A genes in Arabidopsis (Arabidopsis thaliana), is shown to regulate programmed cell death caused by infection with virulent Pseudomonas syringae pv tomato DC3000 (Pst DC3000).

Modulation of eIF5A1 expression alters xylem abundance in Arabidopsis thaliana.

Eukaryotic translation initiation factor 5A (eIF5A) is thought to facilitate protein synthesis by participating in the nuclear export of specific mRNAs. In Arabidopsis, there are three isoforms of eIF5A. One of them, AteIF5A1, has been shown to be expressed in vascular tissue, specifically developing vessel members, using GUS as a reporter.

Regulation and execution of molecular disassembly and catabolism during senescence.

Senescence is a highly orchestrated developmental stage in the life cycle of plants. The onset of senescence is tightly controlled by signaling cascades that initiate changes in gene expression and the synthesis of new proteins. This complement of new proteins includes hydrolytic enzymes capable of executing catabolism of macromolecules, which in turn sets in motion disassembly of membrane molecular matrices, leading to loss of cell function and, ultimately, complete breakdown of cellular ultrastructure.

Characterization of a plastid triacylglycerol lipase from Arabidopsis.

Full-length cDNA corresponding to Arabidopsis (Arabidopsis thaliana) gene At2g31690, which has been annotated in GenBank as a putative triacylglycerol (TAG) lipase, was obtained by reverse transcription-polymerase chain reaction using RNA from senescing rosette leaves of Arabidopsis as a template. The cognate protein was found to contain the lipase active site sequence, and corresponding recombinant protein proved capable of deesterifying TAG. In vitro chloroplast import assays indicated that the lipase is targeted to chloroplasts.

Eukaryotic translation initiation factor 5A induces apoptosis in colon cancer cells and associates with the nucleus in response to tumour necrosis factor alpha signalling.

Eukaryotic translation initiation factor 5A (eIF5A) is thought to function as a nucleocytoplasmic shuttle protein. There are reports of its involvement in cell proliferation, and more recently it has also been implicated in the regulation of apoptosis. In the present study, we examined the effects of eIF5A over-expression on apoptosis and of siRNA-mediated suppression of eIF5A on expression of the tumour suppressor protein, p53.

Diagnostic practices for attention deficit hyperactivity disorder: a national survey of primary care physicians.

Background: The American Academy of Pediatrics (AAP) clinical practice guideline emphasizes the appropriate diagnosis of attention deficit hyperactivity disorder (ADHD) in school-aged children. Although previous studies have shown wide variation in diagnostic practices for ADHD, few recent studies have examined nationally representative samples.

Objective: To describe practice patterns of primary care physicians evaluating school-aged children for ADHD in the late 1990s and compare the patterns with subsequently published AAP guidelines.

Regulation of senescence by eukaryotic translation initiation factor 5A: implications for plant growth and development.

Regulation of protein synthesis is increasingly being recognized as an important determinant of cell proliferation and senescence. In particular, recent evidence indicates that eukaryotic translation initiation factor 5A (eIF-A) plays a pivotal role in this determination. Separate isoforms of eIF-5A appear to facilitate the translation of mRNAs required for cell division and cell death.