Role of leptin in pregnancy: consequences of maternal obesity.

Maternal obesity is associated with increased risks of pregnancy complications. Excessive fat mass, common to obese women, has the potential to influence production and secretion of adipose tissue derived proteins called adipokines. The adipokine leptin is involved in the regulation of multiple aspects of maternal metabolic homeostasis. In addition, leptin has been shown to be important for placentation and maternal-fetal exchanges processes regulating growth and development. In later stages of a healthy pregnancy, central leptin resistance occurs to allow increased nutrient availability for the fetus. Disruption of the signaling capacity of leptin associated with obesity is emerging as a potential risk factor leading to pregnancy complications as a result of aberrant fuel partitioning in utero. In this review we discuss the influence of obesity on the roles of leptin and leptin resistance at the central and placental level.

Passive electrostatic recycling spectrometer of desk-top size for charged particles of low kinetic energy.

A passive electrostatic recycling spectrometer for charged particles is described and demonstrated to store electrons with typical kinetic energies of tens of eV. The design of the charged particle optics and the basic operating characteristics of the storage ring are discussed. The storage lifetime achieved is approximately 50 micros, which is target gas pressure limited and corresponds to approximately 200 orbits of the 0.65 m orbital circumference. The storage ring also has controllable energy dispersive elements enabling it to operate as a spectroscopic device.