Mitochondria Exert a Negative Feedback on the Propagation of Intracellular Ca2+ Waves in Rat Cortical Astrocytes

We have used digital fluorescence imaging techniques to explore the interplay between mitochondrial Ca2+ uptake and physiological Ca2+ signaling in rat cortical astrocytes. A rise in cytosolic Ca2+ ([Ca2+]cyt), resulting from mobilization of ER Ca2+ stores was followed by a rise in mitochondrial Ca2+ ([Ca2+]m, monitored using rhod-2). Whereas [Ca2+]cyt recovered within ∼1 min, the time to recovery for [Ca2+]m was ∼30 min. Dissipating the mitochondrial membrane potential (Δψm, using the mitochondrial uncoupler carbonyl cyanide p-trifluoromethoxy-phenyl-hydrazone [FCCP] with oligomycin) prevented mitochondrial Ca2+ uptake and slowed the rate of decay of [Ca2+]cyt transients, suggesting that mitochondrial Ca2+ uptake plays a significant role in the clearance of physiological [Ca2+]cyt loads in astrocytes. Ca2+ signals in these cells initiated either by receptor-mediated ER Ca2+ release or mechanical stimulation often consisted of propagating waves (measured using fluo-3). In response to either stimulus, the wave traveled at a mean speed of 22.9 ± 11.2 μm/s (n = 262). This was followed by a wave of mitochondrial depolarization (measured using tetramethylrhodamine ethyl ester [TMRE]), consistent with Ca2+ uptake into mitochondria as the Ca2+ wave traveled across the cell. Collapse of Δψm to prevent mitochondrial Ca2+ uptake significantly increased the rate of propagation of the Ca2+ waves by 50%. Taken together, these data suggest that cytosolic Ca2+ buffering by mitochondria provides a potent mechanism to regulate the localized spread of astrocytic Ca2+ signals

Evaluation of trained volunteer doula services for disadvantaged women in five areas in England: women's experiences

Disadvantaged childbearing women experience barriers to accessing health and social care services and face greater risk of adverse medical, social and emotional outcomes. Support from doulas (trained lay women) has been identified as a way to improve outcomes; however, in the UK doula support is usually paid-for privately by the individual, limiting access among disadvantaged groups. As part of an independent multi-site evaluation of a volunteer doula service, this study examined women's experiences of one-to-one support from a trained volunteer doula during pregnancy, labour and the post-natal period among women living in five low-income communities in England. A mixed methods multi-site evaluation was conducted with women (total n = 137) who received the service before December 2012, using a combination of questionnaires (n = 136), and individual or group interviews (n = 12). Topics explored with women included the timing and nature of support, its impact, the relationship with the doula and negative experiences. Most women valued volunteer support, describing positive impacts for emotional health and well-being, and their relationships with their partners. Such impacts did not depend upon the volunteer's presence during labour and birth. Indeed, only half (75/137; 54.7%) had a doula attend their birth. Many experienced volunteer support as a friendship, distinct from the relationships offered by healthcare professionals and family. This led to potential feelings of loss in these often isolated women when the relationship ended. Volunteer doula support that supplements routine maternity services is potentially beneficial for disadvantaged women in the UK even when it does not involve birth support. However, the distress experienced by some women at the conclusion of their relationship with their volunteer doula may compromise the service's impact. Greater consideration is needed for managing the ending of a one-to-one relationship with a volunteer, particularly given the likelihood of it coinciding with a period of heightened emotional vulnerability

The importance of role models and demographic context for senior women's work identity development

The lack of senior female role models continues to be cited as a key barrier to women's career success. Yet there is little academic research into the gendered aspects of role modelling in organizations, or the utility of role models at a senior level. The paper starts with a review of papers examining the construction of role models in organizational settings. This leads to the inclusion of two related areas – organizational demographics as the contextual factor affecting the availability of role models and how they are perceived, and work identity formation as a possible key explanatory factor behind the link between the lack of senior female role models and the lack of career progression to top organizational levels. The literature looking at social theories of identity formation is then considered from a gender perspective. The key gaps identified are that while the behavioural value of role models has been well documented, a better understanding is needed of how gender and organizational demography influence the role modelling process. Importantly, the symbolic value and possibly other values of female role models in the identity construction of senior women require further in-depth investigation. Finally, this review calls for a more integrated approach to the study of role models and work identity formation, pulling together literatures on organizational demography, the cognitive construal of role models and their importance for successful work identity formation in senior women