National Autonomous University of Mexico

About: National Autonomous University of Mexico is a education organization based out in Mexico City, Distrito Federal, Mexico. It is known for research contribution in the topics: Population & Galaxy. The organization has 72868 authors who have published 127797 publications receiving 2285543 citations. The organization is also known as: UNAM & Universidad Nacional Autónoma de México.

Roles of prolactin and related members of the prolactin/growth hormone/placental lactogen family in angiogenesis

Abstract: Prolactin, growth hormone and placental lactogen are members of a family of polypeptide hormones which share structural similarities and biological activities. Numerous functions have been attributed to these hormones, among which stand out their recently discovered effects on angiogenesis, the process by which new blood vessels are formed from the pre-existing microvasculature. Prolactin, growth hormone and placental lactogen, along with two non-classical members of the family, proliferin and proliferin-related protein, can act both as circulating hormones and as paracrine/autocrine factors to either stimulate or inhibit various stages of the formation and remodeling of new blood vessels, including endothelial cell proliferation, migration, protease production and apoptosis. Such opposing actions can reside in similar but independent molecules, as is the case of proliferin and proliferin-related protein, which stimulate and inhibit angiogenesis respectively. The potential to exert opposing effects on angiogenesis can also reside within the same molecule as the parent protein can promote angiogenesis (i.e. prolactin, growth hormone and placental lactogen), but after proteolytic processing the resulting peptide fragment acquires anti-angiogenic properties (i.e. 16 kDa prolactin, 16 kDa growth hormone and 16 kDa placental lactogen). The unique properties of the peptide fragments versus the full-length molecules, the regulation of the protease responsible for specific protein cleavage, the selective expression of specific receptors and their associated signal transduction pathways are issues that are being investigated to further establish the precise contribution of these hormones to angiogenesis under both physiological and pathological situations. In this review article, we summarize the known and speculative issues underlying the effects of the prolactin, growth hormone and placental lactogen family of proteins on angiogenesis, and address important remaining enigmas in this field of research.

High Adiponectin Concentrations Are Associated with the Metabolically Healthy Obese Phenotype

Abstract: Context: In the ob/ob mice, keeping adiponectin concentrations in the physiological range (through overexpression of this gene in the adipose tissue) results in expansion of fat mass and protection against metabolic co-morbidities. Objective: The aim of the study was to test in humans whether plasma adiponectin levels, similar to those found in lean subjects, are associated with the metabolically healthy obese phenotype. Design and Setting: A cross-sectional analysis was performed of a cohort of obese and nonobese subjects aged 18–70 yr. A medical history was taken, and glucose, plasma lipids, and total adiponectin were measured. Participants: We studied 189 men and 527 women. The majority were obese (n = 470, 65.6%). The metabolically healthy obese phenotype was found in 38 men and 133 women. This is defined as a body mass index (BMI) above 30 kg/m2 plus high-density lipoprotein cholesterol of at least 40 mg/dl in the absence of type 2 diabetes and arterial hypertension. Results: Twenty percent of the ca...

Molecular cloud evolution. I. Molecular cloud and thin CNM sheet formation

Abstract: We discuss molecular cloud formation by large-scale supersonic compressions in the diffuse warm neutral medium (WNM). Initially, a shocked layer forms, and within it, a thin cold layer. An analytical model and high-resolution 1D simulations predict the thermodynamic conditions in the cold layer. After $\sim 1$ Myr of evolution, the layer has column density $\sim 2.5 \times 10^{19} \psc$, thickness $\sim 0.03$ pc, temperature $\sim 25$ K and pressure $\sim 6650$ K $\pcc$. These conditions are strongly reminiscent of those recently reported by Heiles and coworkers for cold neutral medium sheets. In the 1D simulations, the inflows into the sheets produce line profiles with a central line of width $\sim 0.5 \kms$ and broad wings of width $\sim 1 \kms$. 3D numerical simulations show that the cold layer develops turbulent motions and increases its thickness, until it becomes a fully three-dimensional turbulent cloud. Fully developed turbulence arises on times ranging from $\sim 7.5$ Myr for inflow Mach number $\Mr = 2.4$ to $> 80$ Myr for $\Mr = 1.03$. These numbers should be considered upper limits. The highest-density turbulent gas (HDG, $n > 100 \pcc$) is always overpressured with respect to the mean WNM pressure by factors 1.5--4, even though we do not include self-gravity. The intermediate-density gas (IDG, $10 < n [{\rm cm}^ {-3}] < 100$) has a significant pressure scatter that increases with $\Mr$, so that at $\Mr = 2.4$, a significant fraction of the IDG is at a higher pressure than the HDG. Our results suggest that the turbulence and at least part of the excess pressure in molecular clouds can be generated by the compressive process that forms the clouds themselves, and that thin CNM sheets may be formed transiently by this mechanism, when the compressions are only weakly supersonic.