The visual perception of long outdoor distances.

Many previous studies have investigated visual distance perception, especially for small to moderate distances. Few experiments, however, have evaluated the perception of large distances (e.g.

Aging and temporal integration in the visual perception of object shape.

It has been known for more than 160 years that highly occluded objects that would normally be visually unrecognizable can be successfully identified when they move. This anorthoscopic perception relies on the visual system's ability to integrate information over time to complete the perception of an entire object's shape. In this experiment, 16 younger and older adults (mean ages were 20.

Aging and the detection of moving objects defined by common fate.

Grouping by common fate plays an important role in how human observers perceive environmental objects. In this study, the effect of aging upon the ability to utilize common fate was evaluated. Twenty-two younger and older adults (mean ages were 23.

Antioxidant defenses in the rat placenta in late gestation: increased labyrinthine expression of superoxide dismutases, glutathione peroxidase 3, and uncoupling protein 2.

Placental oxidative stress plays a key role in the pathophysiology of placenta-related disorders, most notably preeclampsia (PE) and intrauterine growth restriction (IUGR). Oxidative stress occurs when accumulation of reactive oxygen species (ROS) damages DNA, proteins and lipids, an outcome that is limited by antioxidant enzymes; mitochondrial uncoupling protein 2 (UCP2) may also limit oxidative stress by reducing ROS production. Here we characterized placental antioxidant defenses during normal gestation and following glucocorticoid-induced IUGR.

Changes in the placental glucocorticoid barrier during rat pregnancy: impact on placental corticosterone levels and regulation by progesterone.

Glucocorticoid excess in utero inhibits fetal growth and programs adverse outcomes in adult offspring. Access of maternal glucocorticoid to the glucocorticoid receptor (NR3C1) in the placenta and fetus is regulated by metabolism via the 11beta-hydroxysteroid dehydrogenase (HSD11B) enzymes, as well as multidrug resistance P-glycoprotein (ABCB1)-mediated efflux of glucocorticoids from the syncytiotrophoblast. This study determined expression of genes encoding the two HSD11B isoforms (Hsd11b1 and Hsd11b2), the two ABCB1 isoforms (Abcb1a and Abcb1b), and Nr3c1 in the junctional and labyrinth zones of rat placentas at Days 16 and 22 of normal gestation (Day 23 is term).

Reiterated Wnt signaling during zebrafish neural crest development.

While Wnt/beta-catenin signaling is known to be involved in the development of neural crest cells in zebrafish, it is unclear which Wnts are involved, and when they are required. To address these issues we employed a zebrafish line that was transgenic for an inducible inhibitor of Wnt/beta-catenin signaling, and inhibited endogenous Wnt/beta-catenin signaling at discrete times in development. Using this approach, we defined a critical period for Wnt signaling in the initial induction of neural crest, which is distinct from the later period of development when pigment cells are specified from neural crest.

Real-time visualization of mycobacterium-macrophage interactions leading to initiation of granuloma formation in zebrafish embryos.

Infection of vertebrate hosts with pathogenic Mycobacteria, the agents of tuberculosis, produces granulomas, highly organized structures containing differentiated macrophages and lymphocytes, that sequester the pathogen. Adult zebrafish are naturally susceptible to tuberculosis caused by Mycobacterium marinum. Here, we exploit the optical transparency of zebrafish embryos to image the events of M.