Long-term postmenopausal estrogen therapy may be associated with increased risk of breast cancer: a cohort study.

Reports of a role of postmenopausal estrogen replacement therapy in the development of breast cancer have been inconsistent. Although many epidemiologic studies have failed to show an association between short-term use of estrogen and breast cancer, there are indications that long-term use may present an increased risk. We undertook a long-term, retrospective cohort study of the incidence of breast cancer in women who had taken long-term estrogen (average 17.2 years), compared to women who had not taken estrogen. Subjects were 454 women born between 1900 and 1915, who were members of a large health maintenance organization in northern California. By the end of 1995, 26 (11.2%) of estrogen users developed breast cancer, as did 9 (4.1%) of the nonusers; the relative risk (RR) for estrogen use was 2.8 [95% confidence interval (95% CI) 1.3-5.9]. Adjustment for age and multiple breast cancer risk factors, including breast cancer surveillance, reduced the RR for estrogen to 2.0 (95% CI 0.9-4.5). We conclude that long-term estrogen use is associated with a substantially increased risk of breast cancer.

A Brief Mindfulness-Based Intervention for Primary Care Physicians: A Pilot Randomized Controlled Trial.

Primary care physicians experience high rates of burnout, which results in diminished quality of life, poorer quality of care, and workforce attrition. In this randomized controlled trial, our primary aim was to examine the impact of a brief mindfulness-based intervention (MBI) on burnout, stress, mindfulness, compassion, and resilience among physicians. A total of 33 physicians completed the baseline assessment and were randomized to the Mindful Medicine Curriculum (MMC; n = 17) or waitlist control group (n = 16). Participants completed self-report measures at baseline, post-MBI, and 3-month follow-up. We also analyzed satisfaction with doctor communication (DCC) and overall doctor rating (ODR) data from patients of the physicians in our sample. Participants in the MMC group reported significant improvements in stress (P < .001), mindfulness (P = .05), emotional exhaustion (P = .004), and depersonalization (P = .01) whereas in the control group, there were no improvements on these outcomes. Although the MMC had no impact on patient-reported DCC or ODR, among the entire sample at baseline, DCC and ODR were significantly correlated with several physician outcomes, including resilience and personal achievement. Overall, these findings suggest that a brief MBI can have a positive impact on physician well-being and potentially enhance patient care.

Attributional style and anxiety sensitivity as maintenance factors of posttraumatic stress symptoms: A prospective examination of a diathesis-stress model.

Diathesis-stress models of posttraumatic stress disorder (PTSD) assert that traumatic events function as stressors that interact with vulnerabilities to influence the development of PTSD. The present study prospectively examined negative attributional style (NAS) and anxiety sensitivity (AS) as maintenance factors for PTSD in female adult sexual assault victims. A diathesis-stress model was tested by examining interactions between the vulnerabilities and negative life events. The present study included both the traditional three-factor model of PTSD (re-experiencing, avoidance and emotional numbing, and arousal) and the dysphoria four-factor model of PTSD (re-experiencing, avoidance, arousal, and dysphoria). Robust regression analyses revealed that negative life events at Time 2 significantly predicted increases in all clusters of the three-factor model (i.e., re-experiencing, avoidance and numbing, and arousal) and the re-experiencing, arousal, and dysphoria clusters of the four-factor model (but not avoidance). Neither NAS nor AS significantly independently predicted any of the symptom clusters for either model. Both NAS and AS interacted with negative life events to predict increases in the avoidance and numbing symptoms. However, examination of the dysphoria four-factor model of PTSD revealed that the NAS and AS interactions with negative life events only predicted dysphoria symptoms.

Myeloid lineage progenitors give rise to vascular endothelium.

Despite an important role in vascular development and repair, the origin of endothelial progenitors remains unknown. Accumulating evidence indicates that cells derived from the hematopoietic system participate in angiogenesis. However, the identity and functional role of these cells remain controversial. Here we show that vascular endothelial cells can differentiate from common myeloid progenitors and granulocyte/macrophage progenitors. Endothelial cells derived from transplanted bone marrow-derived myeloid lineage progenitors expressed CD31, von Willebrand factor, and Tie2 but did not express the hematopoietic markers CD45 and F4/80 or the pericyte markers desmin and smooth muscle actin. Lineage tracing analysis in combination with a Tie2-driven Cre/lox reporter system revealed that, in contrast to bone marrow-derived hepatocytes, bone marrow-derived endothelial cells are not the products of cell fusion. The establishment of both hematopoietic and endothelial cell chimerism after parabiosis demonstrates that circulating cells can give rise to vascular endothelium in the absence of acute radiation injury. Our findings indicate that endothelial cells are an intrinsic component of myeloid lineage differentiation and underscore the close functional relationship between the hematopoietic and vascular systems.

Prosocial behavior: multilevel perspectives.

Current research on prosocial behavior covers a broad and diverse range of phenomena. We argue that this large research literature can be best organized and understood from a multilevel perspective. We identify three levels of analysis of prosocial behavior: (a) the "meso" level--the study of helper-recipient dyads in the context of a specific situation; (b) the micro level--the study of the origins of prosocial tendencies and the sources of variation in these tendencies; and (c) the macro level--the study of prosocial actions that occur within the context of groups and large organizations. We present research at each level and discuss similarities and differences across levels. Finally, we consider ways in which theory and research at these three levels of analysis might be combined in future intra- and interdisciplinary research on prosocial behavior.

Anxiety, Cognitive Development, and Correspondence: Attributions and Behavioral Prescriptions.

Subjects (N = 261) blocked on their levels of trait anxiety and cognitive development were asked to make causal attributions to account for another person's failure on a task and to prescribe ways to improve the individual's subsequent performance. Subjects at the formal-operational stage and low and moderate levels of trait anxiety showed reliable attribution-behavior prescription correspondence; formal-operational individuals with high trait anxiety and subjects at lower levels of cognitive development showed no consistent relationships between their attributions and subsequent behavioral prescriptions.

Justice within social dilemmas.

The defining feature of social dilemma situations is the inherent conflict faced by those involved: should one act in his or her own individual best interest or sacrifice a measure of one's personal payoff to help maximize the joint payoff of the group as a whole? In such dilemmas, those making individualistic and defecting choices are always at a competitive advantage relative to those who choose to cooperate. One seemingly inevitable consequence of the resulting resource allocation asymmetry is that it must challenge and threaten the cooperator's sense of fairness and justice, and it is the reaction of those caught in social dilemmas to this injustice and unfairness that is the focus of this article. We examine how justice processes-distributive justice, procedural justice, restorative justice, and retributive justice-operate in social dilemmas. Within this examination, we consider ideas from classic and contemporary conceptual analyses of justice to provide a broader context within which to understand social dilemmas and the roles that justice plays as people strive to ensure fair outcomes for themselves and for others. We conclude with the proposal of a 4-stage, sequential model of justice in social dilemmas that posits groups move between the types of justice concerns when unfair and unsatisfactory outcomes (e.g., inequitable resource allocations, violations of agreed-on allocation rules, intentional and egregious exploitation of the group) cause members to "recognize the necessity" for change to ensure fair and just outcomes for all.

Transplanted adult hematopoietic stems cells differentiate into functional endothelial cells.

During early embryogenesis, blood vessels and hematopoietic cells arise from a common precursor cell, the hemangioblast. Recent studies have identified endothelial progenitor cells in the peripheral blood, and there is accumulating evidence that a subset of these cells is derived from precursors in the bone marrow. Here we show that adult bone marrow-derived, phenotypically defined hematopoietic stem cells (c-kit+, Sca-1+, lineage-) give rise to functional endothelial cells. With the exception of the brain, donor-derived cells are rapidly integrated into blood vessels. Durably engrafted endothelial cells express CD31, produce von Willebrand factor, and take up low-density lipoprotein. Analysis of DNA content indicates that donor-derived endothelial cells are not the products of cell fusion. Self-renewal of stem cells with hematopoietic and endothelial cell potential was revealed by serial transplantation studies. The clonal origin of both hematopoietic and endothelial cell outcomes was established by the transfer of a single cell. These results suggest that adult bone marrow-derived hematopoietic stem cells may serve as a reservoir for endothelial cell progenitors.