Intraluminal Cell Transplantation Prevents Growth and Rupture in a Model of Rupture-Prone Saccular Aneurysms

BACKGROUND AND PURPOSE Aneurysm occlusion by intraluminal thrombus formation is the desired effect of all endovascular treatments. Intraluminal thrombus may, however, recanalize and be absorbed, unless it is infiltrated by cells that turn it into fibrous tissue (neointima). Because ruptured aneurysm walls are characterized by loss of smooth muscle cells, we assessed the impact of mural cell loss on wall remodeling of thrombosed aneurysms and investigated whether neointima formation could be enhanced by direct transplantation of cells into the thrombus. METHODS Sidewall aneurysms were microsurgically created in rats (n=81). Certain aneurysms were decellularized. Thrombosis was induced using direct injection of a fibrin polymer into the aneurysm. CM-Dil-labeled smooth muscle cells were injected into 25 of 46 fibrin embolized aneurysms. Recanalization and aneurysm growth were monitored with magnetic resonance angiography. Endoscopy, optical projection tomography, histology, and immunohistochemistry were used to study the fate of transplanted cells, thrombus organization, and neointima formation. RESULTS Decellularized embolized aneurysms demonstrated higher angiographic recurrence compared with decellularized embolized aneurysms with transplanted cells (P=0.037). Local cell replacement at the time of thrombosis resulted in better histological neointima formation than both nondecellularized embolized aneurysms (P<0.001) and decellularized embolized aneurysms (P=0.002). Aneurysm growth and rupture were observed exclusively in decellularized embolized aneurysms. CONCLUSIONS Lack of smooth muscle cells in the aneurysm wall promotes wall degradation, aneurysm growth and rupture, even if the aneurysm is occluded by luminal thrombus. Transplantation of smooth muscle cells into the luminal thrombus can reduce this degenerative remodeling

Cultures’ outcomes on entrepreneurship, innovation, and national quality of life

This theoretical and empirical study applies complexity theory tenets to deepen understanding, explanation, and prediction of how configurations of national cultures and need motivations influence national entrepreneurial and innovation behavior and nations’ quality of life (QOL). Also, the study examines whether or not high national ethical behavior is sufficient for indicating nations high in quality of life. Applying core tenets of complexity theory, the study constructs asymmetric, case-based (nations), explanation, and predictive models of cultures’ consequences (via Schwartz’s seven value dimensions) and implicit need motivations (via McClelland’s three need motivations) indicating national entrepreneur and innovation activities and subsequent national quality of life and ethical behavior. The study includes testing configuration models empirically for predictive accuracy. The empirical examination is for a set of data for 24 nations in Asia, Europe, North and South America, and the South Pacific. The findings confirm the usefulness of applying complexity theory to learn how culture and motivation configurations support versus have negative consequences on nations’ entrepreneurship, innovation, and human well-being. Nurturing of entrepreneur activities supports the nurturing of enterprise innovation activity, and their joint occurrence indicates nations achieving high quality of life. The findings advance the perspective that different sets of cultural value configurations indicate nations high versus low in entrepreneur and innovation activities. High entrepreneur activities without high innovation activity are insufficient for achieving high national quality of life. Achieving high ethical behavior supports high quality of life. This study is one of the first to apply complexity theory tenets in the field of entrepreneurship research. The study here advances the perspective that case-based asymmetric modeling of recipes is necessary to explain and predict entrepreneur activities and outcomes rather than examining whether or not variable relationships are statistically significant from zero.</p

Ecosystem impacts of the widespread non-indigenous species in the Baltic Sea: literature survey evidences major limitations in knowledge

Invasion of non-indigenous species (NIS) is acknowledged as one of the most important external drivers affecting structure and functions of marine ecosystems globally. This paper offers literature-based analysis on the effects of the widespread (occurring in at least 50% of countries) and currently established NIS on ecosystem features in the Baltic Sea. It appears that out of the 18 NIS taxa studied, there are no published records on 28% of NIS for any of the seven impact categories investigated. When ecological impacts are known, laboratory experimental evidence dominates over field studies. Combined observations on impact strength, information type and confidence level suggest that the two benthic invertebrates, the polychaete Marenzelleria spp. and the zebra mussel Dreissena polymorpha (Pallas 1771) exert the highest ecosystem impact. Despite continuously accumulating information on the NIS effects, however, the confidence of findings is still low. Thus, we still understand very little on both the direction and magnitude of the effects of even the most widespread NIS on the structure and dynamics of the Baltic Sea ecosystems. In order to increase reliability of such assessments, future research should be targeted towards spatially-explicit field surveys and experimenting of multitrophic systems, together with modelling of ecosystem impact

Impacts of changing climate on the non-indigenous invertebrates in the northern Baltic Sea by end of the twenty-first century

Biological invasions coupled with climate change drive changes in marine biodiversity. Warming climate and changes in hydrology may either enable or hinder the spread of non-indigenous species (NIS) and little is known about how climate change modifies the richness and impacts of NIS in specific sea areas. We calculated from climate change simulations (RCO-SCOBI model) the changes in summer time conditions which northern Baltic Sea may to go through by the end of the twenty-first century, e.g., 2-5 A degrees C sea surface temperature rise and even up to 1.75 unit decrease in salinity. We reviewed the temperature and salinity tolerances (i.e., physiological tolerances and occurrence ranges in the field) of pelagic and benthic NIS established in-or with dispersal potential to-the northern Baltic Sea, and assessed how climate change will likely affect them. Our findings suggest a future decrease in barnacle larvae and an increase in Ponto-Caspian cladocerans in the pelagic community. In benthos, polychaetes, gastropods and decapods may become less abundant. By contrast, dreissenid bivalves, amphipods and mysids are expected to widen their distribution and increase in abundance in the coastal areas of the northern Baltic Sea. Potential salinity decrease acts as a major driver for NIS biogeography in the northern Baltic Sea, but temperature increase and extended summer season allow higher reproduction success in bivalves, zooplankton, amphipods and mysids. Successful NIS, i.e., coastal crustacean and bivalve species, pose a risk to native biota, as many of them have already demonstrated harmful effects in the Baltic Sea