Search results for "pause"

The Impact of Estrogen Decline on Other Noncommunicable Diseases

2017

Estrogens have specific receptors spread out in various systems of the organism. The drastic hormonal fall after menopause may be followed by a series of effects, which may be more or less relevant in the different areas of the organism. The bone constitutes a field that clearly reflects that impact, and postmenopausal osteoporosis has received attention in one ad hoc chapter. The present chapter reviews the impact on functions of the central nervous system, particularly cognition and mood, the skeletal system, specifically osteoarthritis, and the cardiovascular system. The obvious interest of the chapter derives from the importance of the selected systems, which may house highly prevalent …

2020

Abstract. Cirrus clouds and their potential formation regions, so-called ice supersaturated regions (ISSRs), with values of relative humidity with respect to ice exceeding 100 %, occur frequently in the tropopause region. It is assumed that ISSRs and cirrus clouds can change the tropopause structure by diabatic processes, driven by latent heating due to phase transition and interaction with radiation. For many research questions, a three-dimensional picture including a sufficient temporal resolution of the water vapour fields in the tropopause region is required. This requirement is fulfilled nowadays by reanalysis products such as the European Centre for Medium-Range Weather Forecasts (ECM…

2020

In midlife, women experience hormonal changes due to menopausal transition. A decrease especially in estradiol has been hypothesized to cause loss of muscle mass. This study investigated the effect of menopausal transition on changes in lean and muscle mass, from the total body to the muscle fiber level, among 47–55-year-old women. Data were used from the Estrogenic Regulation of Muscle Apoptosis (ERMA) study, where 234 women were followed from perimenopause to early postmenopause. Hormone levels (estradiol and follicle stimulating hormone), total and regional body composition (dual-energy X-ray absorptiometry (DXA) and computed tomography (CT) scans), physical activity level (self-reported…

Estrogen Regulates the Satellite Cell Compartment in Females

2018

SUMMARYSkeletal muscle mass, strength, and regenerative capacity decline with age, with many measures showing greater deterioration in females about the time estrogen levels decrease at menopause. Here we show that maintenance of muscle stem cells, satellite cells, as well as self-renewal and differentiation into muscle fibers, are severely compromised by estrogen deficiency. Mechanistically, by hormone replacement, use of a selective estrogen-receptor modulator (bazedoxifene), and conditional estrogen receptor knockout, we implicate 17β-estradiol and satellite cell expression of estrogen receptorα(ERα) and show that estrogen signaling through this receptor is necessary to prevent apoptosis…

Modeling of biomass smoke injection into the lower stratosphere by a large forest fire (Part II): Sensitivity studies

2006

Abstract. The Chisholm forest fire that burned in Alberta, Canada, in May 2001 resulted in injection of substantial amounts of smoke into the lower stratosphere. We used the cloud-resolving plume model ATHAM (Active Tracer High resolution Atmospheric Model) to investigate the importance of different contributing factors to the severe intensification of the convection induced by the Chisholm fire and the subsequent injection of biomass smoke into the lower stratosphere. The simulations show strong sensitivity of the pyro-convection to background meteorology. This explains the observed coincidence of the convective blow-up of the fire plume and the passage of a synoptic cold front. Furthermor…

Life-history traits, abiotic environment and coexistence: The case of two cryptic rotifer species

2015

Abstract Trade-offs are important in life-history evolution and coexistence of competitors. However, how alternative life-history optima might promote competitor coexistence has received little attention. The rotifers Brachionus plicatilis and Brachionus manjavacas are two cryptic species with a considerable ecological overlap in relation to biotic factors. These species often co-occur in temporal brackish ponds characterised by environmental fluctuations. In these rotifers, sexual reproduction results in diapausing stages, which are able to survive through adverse conditions but constrain current population growth. In the present work, the differential responses of both cryptic rotifer spe…

The action of estrogens and progestogens in the young female breast

2018

Evidence from different sources sustains a pro-oncogenic role of hormones, estrogens and progestogens, on the breast. The issue is of interest for young women, who are exposed to the hormonal changes imposed by the ovarian cycle and, often, take hormones with contraceptive purposes. Experimental and clinical studies show that both estrogens and progesterone are involved in mammary development during puberty and lactation, the changes being observed across mammalian species, including humans. Estrogen receptors, and more particularly the alpha isoform, participate in molecular processes of stem cells differentiation and epithelial proliferation through paracrine actions implicating growth fa…

25-hydroxy vitamin D levels in healthy premenopausal women: Association with bone turnover markers and bone mineral density

2008

Abstract Background Vitamin D deficiency is very common in elderly people while there are very few reports on its incidence, determinants and metabolic consequences in young subjects. Results In 608 young healthy premenopausal women participating in the BONTURNO study, levels of 25-hydroxyvitamin D [25(OH)D] below 20 ng/ml were found in almost a third of the women. Its levels were inversely ( P 2 ) and directly with sunlight exposure during the summer time, and latitude: i.e. the higher the latitude over Italy, the higher the 25(OH)D level. In women on contraceptive pill the mean 25(OH)D level was significantly increased even when the data were adjusted for age, BMI and sun exposure. 25(OH)…

Age at menopause predicts age at onset of Parkinson's disease.

2006

We investigated the association between age at onset of Parkinson's disease (PD) and fertile life characteristics in 145 women. Linear regression analyses showed a significant correlation between age at PD onset and age at menopause (P = 0.003), between age at PD onset and fertile life duration (P = 0.008), and a nonsignificant correlation between PD onset and cumulative duration of pregnancies (P = 0.23). These results support the possible role of estrogens in PD.

The influence of apo E phenotypes on the plasma triglycerides response to hormonal replacement therapy during the menopause

2001

Objective: To study the influence of apo E phenotype in plasma lipids, especially in triglycerides levels, in menopausal women receiving hormonal replacement therapy (HRT). Methods: One hundred and ten postmenopausal women were studied. Plasma total cholesterol (TC), HDL-C and triglycerides (TG) were measured before and after 3 months of HRT and the apo E phenotype was determined. According to the apo E phenotype the sample was divided into three groups: E2/E3 (n=28), E3/E3 (n=96) and E4/E3 (n=25). Results: In the pre-treatment state, higher plasma levels of TC and TC/HDL-C ratio were observed in women with phenotype E3/E4 (P<0.0001 and P<0.02, respectively), while higher plasma TG levels w…