1,447 research outputs found
Phylogeographic structure of the pygmy shrew: revisiting the roles of southern and northern refugia in Europe
Southern and northern glacial refugia are considered paradigms that explain the complex phylogeographic patterns and processes of European biota. Here, we provide a revisited statistical phylogeographic analysis of the pygmy shrew Sorex minutus Linnaeus, 1766 (Eulipotyphla, Soricidae) examining the genetic diversity, genetic differentiation and demographic history in the Mediterranean peninsulas and in Western and Central Europe. The results showed support for genetically distinct and diverse phylogeographic groups consistent with southern and northern glacial refugia, as expected from previous studies, but also identified geographical barriers concordant with glaciated mountain ranges during the Last Glacial Maximum (LGM), early diversification events dated between the Upper Pleistocene and Lower Holocene for the main phylogeographic groups, and recent (post-LGM) patterns of demographic expansions. This study is the most comprehensive investigation of this species to date, and the results have implications for the conservation of intraspecific diversity and the preservation of the evolutionary potential of S. minutus
Involvement of Mhc Loci in immune responses that are not Ir-gene-controlled
Twenty-nine randomly chosen, soluble antigens, many of them highly complex, were used to immunize mice of two strains, C3H and B10.RIII. Lymphnode cells from the immunized mice were restimulated in vitro with the priming antigens and the proliferative response of the cells was determined. Both strains were responders to 28 of 29 antigens. Eight antigens were then used to immunize 11 congenic strains carrying different H-2 haplotypes, and the T-cell proliferative responses of these strains were determined. Again, all the strains responded to seven of the eight antigens. These experiments were then repeated, but this time -antibodies specific for the A (AA) or E (EE) molecules were added to the culture to block the in vitro responsiveness. In all but one of the responses, inhibition with both A-specific and E-specific antibodies was observed. The response to one antigen (Blastoinyces) was exceptional in that some strains were nonresponders to this antigen. Furthermore, the response in the responder strains was blocked with A-specific, but not with E-specific, antibodies. The study demonstrates that responses to antigens not controlled by Irr genes nevertheless require participation of class II Mhc molecules. In contrast to Ir gene-controlled responses involving either the A- or the E-molecule controlling loci (but never both), the responses not Ir-controlled involve participation of both A- and E-controlling loci. The lack of Ir-gene control is probably the result of complexity of the responses to multiple determinants. There is thus no principal difference between responses controlled and those not controlled by Ir genes: both types involve the recognition of the antigen, in the context of Mhc molecules
Bone marrow-derived endothelial progenitor cells are a major determinant of nascent tumor neovascularization
Tumors build vessels by cooption of pre-existing vasculature and de novo recruitment of bone marrow (BM)-derived endothelial progenitor cells (EPCs). However, the contribution and the functional role of EPCs in tumor neoangiogenesis are controversial. Therefore, by using genetically marked BM progenitor cells, we demonstrate the precise spatial and temporal contribution of EPCs to the neovascularization of three transplanted and one spontaneous breast tumor in vivo using high-resolution microscopy and flow cytometry. We show that early tumors recruit BM-derived EPCs that differentiate into mature BM-derived endothelial cells (ECs) and luminally incorporate into a subset of sprouting tumor neovessels. Notably, in later tumors, these BM-derived vessels are diluted with non-BM-derived vessels from the periphery, which accounts for purported differences in previously published reports. Furthermore, we show that specific ablation of BM-derived EPCs with alpha-particle-emitting anti-VE-cadherin antibody markedly impaired tumor growth associated with reduced vascularization. Our results demonstrate that BM-derived EPCs are critical components of the earliest phases of tumor neoangiogenesis
The ethos of physical activity delivery in mental health: a narrative study of service user experiences.
Our research into the physical activity experiences of people with severe mental illness has led us to take seriously the social and cultural environment in which physical activity is delivered. In this study, through narrative methodology, we examine service user accounts of physical activity to illuminate the characteristics of physical activity groups that are experienced as positive, helpful, or beneficial. We present several qualities and show how effective leadership and coaching is central to these qualities being present. We conclude that it is not so much what activity is delivered, but how it is delivered that is critical for sustained participation and positive outcomes
Social support for and through exercise and sport in a sample of men with serious mental illness.
Social support is important for people experiencing serious mental illness and is also important during the initiation and maintenance of exercise. In this article we draw on interpretive research into the experiences of 11 men with serious mental illness to explore four dimensions of social support both for and through exercise. Our findings suggest that informational, tangible, esteem, and emotional support were both provided for and given by participants through exercise. We conclude that experiences of both receiving and giving diverse forms of support in this way are significant for some people living with and recovering from serious mental illness
An Exploratory Study into the Factors Impeding Ethical Consumption
Although consumers are increasingly engaged with ethical factors when forming opinions about products and making purchase decisions, recent studies have highlighted significant differences between consumersâ intentions to consume ethically, and their actual purchase behaviour. This article contributes to an understanding of this âethical purchasing gapâ through a review of existing literature, and the inductive analysis of focus group discussions. A model is suggested which includes exogenous variables such as moral maturity and age which have been well covered in the literature, together with further impeding factors identified from the focus group discussions. For some consumers, inertia in purchasing behaviour was such that the decision-making process was devoid of ethical considerations. Several manifested their ethical views through post-purchase dissonance and retrospective feelings of guilt. Others displayed a reluctance to consume ethically due to personal constraints, a perceived negative impact on image or quality, or an outright negation of responsibility. Those who expressed a desire to consume ethically often seemed deterred by cynicism, which caused them to question the impact they, as an individual, could achieve. These findings enhance the understanding of ethical consumption decisions and provide a platform for future research in this area
- âŠ