A critical step in ovarian biology is the transition of the developmentally arrested primordial follicle to the growing primary follicle. The current study utilizes a rat ovarian organ culture system to investigate the role of insulin and insulin-like growth factor-1 (IGF-1) in this process. Four-day-old rat ovaries were cultured and the degree of primordial to primary follicle transition measu...

The majority of ovarian primordial follicles must be preserved in a quiescent state to allow for the regular production of gametes over the female reproductive lifespan. However, the molecular mechanism that maintains the long quiescence of primordial follicles is poorly understood. Under certain pathological conditions, the entire pool of primordial follicles matures simultaneously leading to ...

In this study we show that mouse primordial germ cells and fetal germ cells at certain stages of differentiation express E-cadherin and alpha and beta catenins. Moreover, we demonstrate that the formation of germ cell aggregates that rapidly occurs when monodispersed germ cell populations are released from embryonic gonads in culture is E-cadherin mediated, developmentally regulated, and depend...

We use the δN-formalism to investigate the non-Gaussianity of the primordial curvature perturbation in the curvaton scenario for the origin of structure. We numerically calculate the full probability distribution function allowing for the non-instantaneous decay of the curvaton and compare this with analytic results derived in the sudden-decay approximation. We also present results for the lead...

Female mammals are born with a lifetime's supply of oocytes individually enveloped in flattened epithelial cells to form primordial follicles. It is not clear how sufficient primordial follicles are maintained to sustain the reproductive lifespan, while providing an adequate supply of mature oocytes for ovulation. Locally produced growth factors are thought to be critical regulators of early fo...

A network of extracellular signaling factors has previously been shown to act in concert to control the ovarian primordial to primary follicle transition. The current study was designed to investigate the roles of the endogenous bone morphogenetic protein (BMP) inhibitors Gremlin 1 (GREM1) and GREM2 in primordial follicle transition in the rat ovary. GREM1 and GREM2 treatments were found to rev...

The origin of CMB polarization is reviewed. Special emphasis is placed on the cosmological information encoded in it: the nature of primordial fluctuations, the connection with the inflation paradigm. Insights into more recent epochs are also discussed: early reionization and high redshift matter distribution from CMB lensing. Résumé. L’origine de la polarisation du CMB est passée en revue. On ...

Primordial nucleosynthesis provides a probe of the Universe during its early evolution. Given the progress exploring the constituents, structure, and recent evolution of the Universe, it is timely to review the status of Big Bang Nucleosynthesis (BBN) and to confront its predictions, and the constraints which emerge from them, with those derived from independent observations of the Universe at ...

We discuss the primordial nucleosynthesis in lepton asymmetric Universe models. In order to better estimate the universal baryonmass density parameter Ωb, we try to remove the uncertainty from the theoretical prediction of primordial Li abundance. We propose a new method to determine the primordial Li by the use of isotopic abundance ratio Li/Li in the interstellar medium which exhibits the min...

Fertility in mammals is dependant on females having an adequate primordial follicle pool to supply oocytes for fertilization. The formation of primordial follicles is called ovarian follicular assembly. In rats and mice progesterone and estradiol have been shown to inhibit follicle assembly with assembly occurring after birth when the pups are removed from the high-steroid maternal environment....