5,268 research outputs found
Androgens and Hypertension in Men and Women: a Unifying View.
This review was designed to revaluate the androgen role on the mechanisms of hypertension and cardiovascular risks in both men and women. Sex steroids are involved in the regulation of blood pressure, but pathophysiological mechanism is not well understood. Androgens have an important effect on metabolism, adipose and endothelial cell function, and cardiovascular risk in both men and women. A focal point in this contest is represented by the possible gender-specific regulation of different tissues and in particular of the adipose cell. Available data confirm that androgen deficiency is linked to increased prevalence of hypertension and cardiovascular diseases. Adipocyte dysfunction seems to be the main involved mechanism. Androgen replacement reduces inflammation state in man, protecting by metabolic syndrome progression. In women, androgen excess has been considered as promoting factor of cardiovascular risk. However, recent data suggest that excessive androgen production has little effect per se in inducing hypertension in young women of reproductive age. Also in postmenopausal women, data on relative androgen excess and hypertension are missing, while adrenal androgen deficiency has been associated to increased mortality.
RECENT FINDINGS:
Molecular mechanisms linking androgen dysregulation to hypertension are almost Unknown, but they seem to be related to increased visceral fat, promoting a chronic inflammatory state through different mechanisms. One of these may involve the recruitment and over-activation of NF-kB, a ubiquitous transcription factor also expressed in adipose cells, where it may cause the production of cytokines and other immune factors. The NF-kB signalling pathway may also influence brown adipogenesis leading to the preferential enlargement of visceral adipocytes. Chronic inflammation and adipocyte dysfunction may alter endothelial function leading to hypertension. Both in men and in women, particularly in the post-menopausal period, hypoandrogenism seems to be a major determinant of the increased prevalence of hypertension. The relationship between androgen signalling and NF-kB might explain the pathophysiological mechanism leading to the development of endothelium dysfunction and hypertension
Evaluating the impact of Hymenoscyphus fraxineus in Trentino (Alps, Northern Italy): first investigations
The spread of Hymenoscyphus fraxineus has been causing great concern regarding the survival of European ash (Fraxinus excelsior) throughout Europe since the 1990s. The disease was first recorded in Trentino (southern Alps, Italy) in 2012 and has spread throughout the mountain landscape, where ash trees are scattered in small and isolated stands in different valleys. The status of the disease was checked by monitoring the damage to natural regeneration and adult trees in 90 sites spread over the whole region. The survey confirmed the complete colonization by the pathogen of the whole investigated area, with high levels of damage to both young and adult ash trees. Regeneration (both seedlings and saplings) was observed to be affected by the fungus in 88 plots out of 90. Out of 4486 examined young European ashes, 2261 (50.4%) were affected and 789 (17.6%) were already dead. Ten of the 384 assayed flowering ashes (Fraxinus ornus) showed symptoms on branches and apical stems, similar to those observed for European ash. Isolation and molecular analysis proved the presence of the fungus on both symptomatic European and flowering ashes. The examined 386 adult trees showed different levels of damage, sometimes reaching more than 75% of the crown. Some individual trees (42) growing close to severely damaged trees appeared fully healthy, which suggests the possible existence of some resistant/tolerant individuals in the examined populations
Price dynamics in sequential auctions. New evidence using art auction data
We analyze the price structure of sequential auctions of modern and contemporary art that took place in Italy during the period 1983-96. Contrary to previous empirical studies, we do not find any "afternoon" effect - i.e., a decline of auction prices relative to their estimates. If anything, we find the opposite, or "morning", effect. Our results are robust to different econometric specifications. Taking into consideration the possible dynamic nature of price determination, we propose an interpretation of the empirical results that encompasses previous contributions
Control and coherence of the optical transition of single defect centers in diamond
We demonstrate coherent control of the optical transition of single
Nitrogen-Vacancy defect centers in diamond. On applying short resonant laser
pulses, we observe optical Rabi oscillations with a half-period as short as 1
nanosecond, an order of magnitude shorter than the spontaneous emission time.
By studying the decay of Rabi oscillations, we find that the decoherence is
dominated by laser-induced spectral jumps. By using a low-power probe pulse as
a detuning sensor and applying post-selection, we demonstrate that spectral
diffusion can be overcome in this system to generate coherent photons.Comment: 5 pages,4 figure
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