74 research outputs found
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
GEICAM Guidelines for the Management of Patients with Breast Cancer During the COVID-19 Pandemic in Spain
Breast cancer (BC) is the most common cancer in women in
Spain. During the COVID-19 pandemic caused by the SARSCoV-2 virus, patients with BC still require timely treatment
and follow-up; however, hospitals are overwhelmed with
infected patients and, if exposed, patients with BC are at
higher risk for infection and serious complications if infected.
Thus, health care providers need to evaluate each BC treatment and in-hospital visit to minimize pandemic-associated
risks while maintaining adequate treatment efficacy. Here we
present a set of guidelines regarding available options for BC
patient management and treatment by BC subtype in the
context of the COVID-19 pandemic. Owing to the lack of evidence about COVID-19 infection, these recommendations
are mainly based on expert opinion, medical organizations’
and societies’ recommendations, and some published evidence. We consider this a useful tool to facilitate medical
decision making in this health crisis situation we are facing
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