Cardiac Neural Crest Cells and Their Role in Murine Purkinje Fiber Development

The heart beat is regulated by the cardiac conduction system (CCS), a specialized group of cells that transmit electrical impulses around the heart chambers. During development, ventricular CCS cells originate from embryonic cardiomyocytes and not from the neural crest. Nonetheless, discoveries in chick implied that the cardiac neural crest (CNC) cells contribute to proper development of the ventricular CCS. In this report, the Splotch mouse mutant (Pax3sp), in which the CNC cells do not migrate to the heart, was used to investigate whether these cells also affect proper CCS development in mammals. Homozygote mutants (Pax3Sp!Sp) are lethal on 111 Embryonic Day 13 (E13), and can be phenotyped by spina bifida and exencephaly. Pax3Spi+ mice were crossed to obtain wild type, Pax3 Spi+ and Pax3 Sp!Sp embryos. Comparison of hematoxylin and eosin stained histological sections showed less trabeculation in El2.5 cardiac ventricles of Pax3Sp!Sp. Furthermore, immunofluorescence analysis with the Purkinje fiber marker Cx40 showed a qualitative difference between wild type and mutant hearts. Quantitative analysis indicated that Pax3 Sp!Sp ventricles had fewer Cx40 expressing cells, as well as less Cx40 being expressed per cell when compared to wild type ventricles. Immunofluorescence with the H3 histome mitosis antibody showed fewer proliferating cells in the ventricles of mutant embryos when compared to controls. These results suggest that CNCC affect the morphogenesis of cardiac ventricles and the development of the ventricular CCS by contributing cellular proliferation.

The Modern State and the Re-Creation of the Indigenous Other: The Case of the Authentic Sámi in Sweden and the White Man’s Indian in the United States of America.

The present study comparatively examined the socio-political and economic transformation of the indigenous Sámi in Sweden and the Indian American in the United States of America occurring first as a consequence of colonization and later as a product of interaction with the modern territorial and industrial state, from approximately 1500 to 1900. The first colonial encounters of the Europeans with these autochthonous populations ultimately created an imagery of the exotic Other and of the noble savage. Despite these disparaging representations, the cross-cultural settings in which these interactions took place also produced the hybrid communities and syncretic life that allowed levels of cultural accommodation, autonomous space, and indigenous agency to emerge. By the nineteenth century, however, the modern territorial and industrial state rearranges the dynamics and reaches of power across a redefined territorial sovereign space, consequently, remapping belongingness and identity. In this context, the status of indigenous peoples, as in the case of Sámi and of Indian Americans, began to change at par with industrialization and with modernity. At this point in time, indigenous populations became a hindrance to be dealt with the legal re-codification of Indigenousness into a vacuumed limbo of disenfranchisement. It is, thus, the modern territorial and industrial state that re-creates the exotic into an indigenous Other. The present research showed how the initial interaction between indigenous and Europeans changed with the emergence of the modern state, demonstrating that the nineteenth century, with its fundamental impulses of industrialism and modernity, not only excluded and marginalized indigenous populations because they were considered unfit to join modern society, it also re-conceptualized indigenous identity into a constructed authenticity.

The modern state and the re-creation of the indigenous other: The case of the authentic Sami in Sweden and the white man's Indian in the United States of America

The present study comparatively examined the socio-political and economic transformation of the indigenous Sámi in Sweden and the Indian American in the United States of America occurring first as a consequence of colonization and later as a product of interaction with the modern territorial and industrial state, from approximately 1500 to 1900. ^ The first colonial encounters of the Europeans with these autochthonous populations ultimately created an imagery of the exotic Other and of the noble savage. Despite these disparaging representations, the cross-cultural settings in which these interactions took place also produced the hybrid communities and syncretic life that allowed levels of cultural accommodation, autonomous space, and indigenous agency to emerge. By the nineteenth century, however, the modern territorial and industrial state rearranges the dynamics and reaches of power across a redefined territorial sovereign space, consequently, remapping belongingness and identity. In this context, the status of indigenous peoples, as in the case of Sámi and of Indian Americans, began to change at par with industrialization and with modernity. At this point in time, indigenous populations became a hindrance to be dealt with the legal re-codification of Indigenousness into a vacuumed limbo of disenfranchisement. It is, thus, the modern territorial and industrial state that re-creates the exotic into an indigenous Other. ^ The present research showed how the initial interaction between indigenous and Europeans changed with the emergence of the modern state, demonstrating that the nineteenth century, with its fundamental impulses of industrialism and modernity, not only excluded and marginalized indigenous populations because they were considered unfit to join modern society, it also re-conceptualized indigenous identity into a constructed authenticity.^