Identification of the heart as the critical site of adenosine mediated embryo protection.

Background: Our understanding of the mechanisms that protect the developing embryo from intrauterine stress is limited. Recently, adenosine has been demonstrated to play a critical role in protecting the embryo against hypoxia via adenosine A1 receptors (A1ARs), which are expressed in the heart, nervous system, and other sites during development. However, the sites of A1AR action that mediate embryo protection are not known.

Transforming growth factor beta2 is negatively regulated by endogenous retinoic acid during early heart morphogenesis.

Vitamin A-deficient (VAD) quail embryos lack the vitamin A-active form, retinoic acid (RA) and are characterized by a phenotype that includes a grossly abnormal cardiovascular system that can be rescued by RA. Here we report that the transforming growth factor, TGFbeta2 is involved in RA-regulated cardiovascular development. In VAD embryos TGFbeta2 mRNA and protein expression are greatly elevated.

Prenatal diagnosis of trisomy 21 through detection of trophoblasts in cervical smears.

Background: Fetal cells exfoliate in the uterine cavity during early pregnancy and are a potential source of material for NIPD.

Aims: This study was designed to test the hypothesis that fetal cells obtained from the uterine cervix during the first trimester of pregnancy could be utilized for prenatal diagnosis of chromosomal aneuploidy.

Study Design: Fetal cells retrieved from the distal endocervical canal during the first trimester of pregnancy were hybridized with chromosome 21 specific FISH probes and analyzed with an automated fluorescence microscope.

Embryonic caffeine exposure induces adverse effects in adulthood.

The purpose of this study was to determine both the short-term effects on cardiac development and embryo growth and the long-term effects on cardiac function and body composition of in utero caffeine exposure. Pregnant mice (C57BL/6) were exposed to hypoxia (10% O(2)) or room air from embryonic days (E) 8.5-10.

Gallera method of chick embryo culture in vitro supports better growth compared with original New method.

An avian embryo is a valuable model system for vertebrate embryology. Easy availability, accessibility to various developmental stages and amenability of organ fields makes the chick embryo one of the favored model systems. Seminal discoveries regarding organogenesis and vertebrate morphogenesis have been made using chick embryos cultured in vitro.

Hypoxia induces cardiac malformations via A1 adenosine receptor activation in chicken embryos.

Background: The current understanding of the effects of hypoxia on early embryogenesis is limited. Potential mediators of hypoxic effects include adenosine, which increases dramatically during hypoxic conditions and activates A(1) adenosine receptors (A(1)ARs).

Methods: To examine the influences of hypoxia and adenosine signaling on cardiac development, chicken embryos were studied.

A1 adenosine receptors play an essential role in protecting the embryo against hypoxia.

Embryos can be exposed to environmental factors that induce hypoxia. Currently, our understanding of the effects of hypoxia on early mammalian development is modest. Potential mediators of hypoxia action include the nucleoside adenosine, which acts through A(1) adenosine receptors (A(1)ARs) and mediates adverse effects of hypoxia on the neonatal brain.

Protection against myocardial ischemia-reperfusion injury by the angiogenic Masterswitch protein PR 39 gene therapy: the roles of HIF1alpha stabilization and FGFR1 signaling.

PR-39, a proline-arginine-rich angiogenic response peptide, has been implicated in myocardial ischemic reperfusion injury. The present study examined the cardioprotective abilities of PR39 gene therapy. Male C57Bl/J6 mice were randomized to intramyocardial injecton of 10(9) p.

Bmp2 and Gata4 function additively to rescue heart tube development in the absence of retinoids.

We used the vitamin A-deficient (VAD) quail model to investigate the retinoid-dependent mechanism that regulates heart tube development. We showed previously that decreased levels of Gata4 in cardiogenic mesoderm and endoderm correlate with the cardiomyopathy caused by VAD, but that this could be rescued by transplanting normal anterior endoderm. Bmp2 is a known cardiogenic factor that is expressed normally in lateral plate mesoderm and cardiac-associated pharyngeal endoderm.

Retinoid signaling regulates primitive (yolk sac) hematopoiesis.

It is known from nutritional studies that vitamin A is an important factor for normal hematopoiesis, though it has been difficult to define its precise role. The vitamin A-deficient (VAD) quail embryo provides an effective ligand "knockout" model for investigating the function of retinoids during development. The VAD embryo develops with a significant reduction in erythroid cells, which has not been noted previously.

Lithium Chloride and Trypan Blue Induce Abnormal Morphogenesis by Suppressing Cell Population Growth: (LiCl/trypan blue/chick teratogenesis/cell population growth inhibition).

Full primitive streak stage chick embryos were cultured in vitro for 20 hrs and monitored every 4 hr for morphology, cell number and blastoderm area. In normal embryos, the cell population growth is exponential and correlates directly with Increasing morphological rank. The chick blastoderm area expands in two waves, one immediately after gastrulation and another after 16 hr in culture, while cell population growth is predominant between 4-16 hr.

Cell Population Growth and Area Expansion in Early Chick Embryos During Normal and Abnormal Morphogenesis in vitro: (trypan blue, chick embryo/teratogenesis/cell population growth/blastoderm expansion).

The exponential growth and cell population during the early embryogenesis of chick, cultured in vitro correlates with a linear increase in the blastoderm area. To understand the relationship between these parameters and normal morphogenesis, we have used a known teratogen, trypan blue, as a probe. A method is developed in which each new embryonic structure is assigned a rank value of 1 and the total number of ranks allows quantification of development and establishment of a numerical relationship between the size of the cell population, blastoderm area and the morphological development.