Exocytosis of catecholamine (CA)-containing and CA-free granules in chromaffin cells.

Recent evidence suggests that endocytosis in neuroendocrine cells and neurons can be tightly coupled to exocytosis, allowing rapid retrieval from the plasma membrane of fused vesicles for future use. This can be a much faster mechanism for membrane recycling than classical clathrin-mediated endocytosis. During a fast exo-endocytotic cycle, the vesicle membrane does not fully collapse into the plasma membrane; nevertheless, it releases the vesicular contents through the fusion pore. Once the vesicle is depleted of transmitter, its membrane is recovered without renouncing its identity. In this report, we show that chromaffin cells contain catecholamine-free granules that retain their ability to fuse with the plasma membrane. These catecholamine-free granules represent 7% of the total population of fused vesicles, but they contributed to 47% of the fusion events when the cells were treated with reserpine for several hours. We propose that rat chromaffin granules that transiently fuse with the plasma membrane preserve their exocytotic machinery, allowing another round of exocytosis

Interacciones entre Geomorfología e intervención humana sobre la composición del matorral en la cuenca del río Guadalupejo (Extremadura)

19 páginas, 4 figuras, 2 tablas, 30 referencias.[EN]: The relationships between geomorphology and scrub composition and the effects of management practices on them bave been studied in Guadalupejo River bassin (W. Spain). The mediterranean climate has an annual precipitation of 803 mm and average temperature of 15ºC. Lithology is dominated by slates with surface deposits of conglomerates and clay. The area was subdivided on homogeneous units with geomorphic and management criteria in order to sample vegetation. Pressence/absence and abundance (as cover) of 30 scrub species was recorded on 56 10 x 10m. plots. Cluster analysis was used to classify vegetation types. Main type divisions are related primarily to human management and secondarily to geomorphic and physicochemical characters of substrate. Total plant cover, specific species contribution and pioneer/mature species ratio a1l are influenced by the predominant factors mentioned above. The relative weight of physical, biotic and human factors in determining vegetation composition is discussed. It is proposed that all processes involved may fall into three main categories: limitation, organisation and disruption.[ES]: Se han estudiado las relaciones entre geomorfología y composición del matorral mediterráneo y el efecto de la intervención humana sobre las mismas. Se escogió la parte baja de la cuenca del río Guadalupejo, afluente del Guadiana por su margen derecha. El clima es de tipo mediterráneo (803 mm; y 15°) y el sustrato está formado por pizarras, conglomerados y arcillas. Se sectorizó el área con criterios geomorfológicos y de tipos de intervención humana como base para el muestreo estratificado de la vegetación; se registró la presencia de las especies y se midió su cobertura en 36 parcelas de 10 x 10 m. La Matriz de datos cualitativos se analizó mediante técnicas de análisis de clasificación aglomerativa, para determinar tipos de matorral. Las principales diferencias entre los tipos de matorral se relacionan en primer lugar con la modalidad de intervención humana y en segundo con la geomorfología y composición fisicoquímica del sustrato. La cobertura total del matorral, importancia relativa de las distintas especies y relación entre coberturas especies pioneras/especies maduras también se relacionan con estos factores predominantes. Se discute la importancia de los procesos físicos, bióticos y humanos en la determinación de la composición de la vegetación, considerándolos agrupados en 3 grupos de procesos, limitativos, organizativos y desorganizativos.Peer reviewe

Harmonic Distortion Index for Stationary and Transient States

Abstract. For transient or aperiodic signals the Fourier analysis is unable to obtain accurate results and a joint timefrequency analysis must be used to provide simultaneous time and frequency information of transient intervals. A power quality index is proposed for evaluation of both the stationary and transient quality aspects of electrical signals. The widely used total harmonic distortion index (THD) is redefined in this paper to include harmonics, oscillatory transients, voltage sags and swells. The new index is defined between the 0-1 range

Preventive treatments for breast cancer: recent developments

Breast cancer is a burden for western societies, and an increasing one in emerging economies, because of its high incidence and enormous psychological, social, sanitary and economic costs. However, breast cancer is a preventable disease in a significant proportion. Recent developments in the armamentarium of effective drugs for breast cancer prevention (namely exemestane and anastrozole), the new recommendation from the National Institute for Health and Care Excellence to use preventative drugs in women at high risk as well as updated Guidelines from the US Preventive Services Task Force and the American Society of Clinical Oncology should give renewed momentum to the pharmacological prevention of breast cancer. In this article we review recent major developments in the field and examine their ongoing repercussion for breast cancer prevention. As a practical example, the potential impact of preventive measures in Spain is evaluated and a course of practical actions is delineated

What seems to explain suicidality in Yucatan Mexican young adults? findings from an app-based mental health screening test using the SMART-SCREEN protocol

The relationship between suicidality, depression, anxiety, and well-being was explored in young adults (median age 20.7 years) from the State of Yucatan (Mexico), which has a suicide rate double that of other Mexican states. A cross-sectional study was carried out in 20 universities in Yucatan and 9,366 students were surveyed using validated questionnaires built into a smartphone app, applying partial least squares structural equation models. High suicide risk was assessed in 10.8% of the sample. Clinically relevant depression and anxiety levels were found in 6.6% and 10.5% of the sample, respectively, and 67.8% reported high well-being. Comparably higher levels of suicide risk, depression and anxiety, and lower well-being were found in women, who were also somewhat older than men in our study. Furthermore, path analysis in the structural equation model revealed that depression was the main predictor of suicidal behaviour as well as of higher anxiety levels and lower self-perceived well-being in the total sample and in both genders. Our findings draw attention to the association between suicidality, depression, anxiety, and well-being in Yucatan young adults and gender differences with this regard. Mental health screening via smartphone might be a useful tool to reach large populations and contribute to mental health policies, including regional suicide prevention effortsOpen Access funding provided thanks to the CRUE-CSIC agreement with Springer Nature. No funding was received for this stud

Exemestane for breast-cancer prevention in postmenopausal women

Background: tamoxifen and raloxifene have limited patient acceptance for primary prevention of breast cancer. Aromatase inhibitors prevent more contralateral breast cancers and cause fewer side effects than tamoxifen in patients with early-stage breast cancer. Methods: in a randomized, placebo-controlled, double-blind trial of exemestane designed to detect a 65% relative reduction in invasive breast cancer, eligible postmenopausal women 35 years of age or older had at least one of the following risk factors: 60 years of age or older; Gail 5-year risk score greater than 1.66% (chances in 100 of invasive breast cancer developing within 5 years); prior atypical ductal or lobular hyperplasia or lobular carcinoma in situ; or ductal carcinoma in situ with mastectomy. Toxic effects and health-related and menopause-specific qualities of life were measured. Results: a total of 4560 women for whom the median age was 62.5 years and the median Gail risk score was 2.3% were randomly assigned to either exemestane or placebo. At a median follow-up of 35 months, 11 invasive breast cancers were detected in those given exemestane and in 32 of those given placebo, with a 65% relative reduction in the annual incidence of invasive breast cancer (0.19% vs. 0.55%; hazard ratio, 0.35; 95% confidence interval [CI], 0.18 to 0.70; P=0.002). The annual incidence of invasive plus noninvasive (ductal carcinoma in situ) breast cancers was 0.35% on exemestane and 0.77% on placebo (hazard ratio, 0.47; 95% CI, 0.27 to 0.79; P=0.004). Adverse events occurred in 88% of the exemestane group and 85% of the placebo group (P=0.003), with no significant differences between the two groups in terms of skeletal fractures, cardiovascular events, other cancers, or treatment-related deaths. Minimal quality-of-life differences were observed. Conclusions: exemestane significantly reduced invasive breast cancers in postmenopausal women who were at moderately increased risk for breast cancer. During a median follow-up period of 3 years, exemestane was associated with no serious toxic effects and only minimal changes in health-related quality of life