858 research outputs found

    Aloha to Social Studies: an Integrated Curricular Unit

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    In recent years teachers have struggled to find the time to dedicate to teaching social studies concepts. However, social studies instruction is an integral part of a balanced educational program. In addition to imparting factual information, social studies curricula encourage critical thinking skills and help to prepare students to become responsible members of society. This research project was intended to provide educators with a model of how to integrate social studies with other academic areas to maximize instructional time and the amount of content covered. The unit was reviewed by master teachers to ensure that the project goals were attained. Limitations to the project and suggestions for further study were included in Chapter Five

    Endothelial cell regulation of leukocyte infiltration in inflammatory tissues

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    Endothelial cells play an important, active role in the onset and regulation of inflammatory and immune reactions. Through the production of chemokines they attract leukocytes and activate their adhesive receptors. This leads to the anchorage of leukocytes to the adhesive molecules expressed on the endothelial surface. Leukocyte adhesion to endothelial cells is frequently followed by their extravasation. The mechanisms which regulate the passage of leukocytes through endothelial clefts remain to be clarified. Many indirect data suggest that leukocytes might transfer signals to endothelial cells both through the release of active agents and adhesion to the endothelial cell surface. Adhesive molecules (such as PECAM) on the endothelial cell surface might also ‘direct’ leukocytes through the intercellular junction by haptotaxis. The information available on the molecular structure and functional properties of endothelial chemokines, adhesive molecules or junction organization is still fragmentary. Further work is needed to clarify how they interplay in regulating leukocyte infiltration into tissues

    A murine model of cerebral cavernous malformations with acute hemorrhage

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    Cavernomas are multi-lumen and blood-filled vascular malformations which form in the brain and the spinal cord. They lead to hemorrhage, epileptic seizures, neurological deficits, and paresthesia. An effective medical treatment is still lacking, and the available murine models for cavernomas have several limitations for preclinical studies. These include disease phenotypes that differ from human diseases, such as restriction of the lesions to the cerebellum, and absence of acute hemorrhage. Additional limitations of current murine models include rapid development of lesions, which are lethal before the first month of age. Here, we have characterized a murine model that recapitulates features of the human disease: lesions develop after weaning throughout the entire CNS, including the spinal cord, and undergo acute hemorrhage. This provides a preclinical model to develop new drugs for treatment of acute hemorrhage in the brain and spinal cord, as an unmet medical emergency for patients with cavernomas

    NOCTUA: potenzialità innovative per l'Osservazione della Terra

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    SAR systems have notable and interesting applications in Earth Observation, in particular in environmental and infrastructure monitoring, in the control of water resources, oceans and coasts and in the control of agricultural and forest resources. Relevant added value of the SAR is to acquire images in all weather conditions to help in the prevention and analysis of disasters due to natural or anthropogenic causes and for all precursor phenomena of environmental disasters. In this scenario NOCTUA, a project carried out by a partnership leaded by D-Orbit and funded by Lombardia Region, offers multiple opportunities, representing a platform with SAR sensor at competitive costs and with excellent acquisition performance on the international scene

    Vascular endothelial growth factor C disrupts the endothelial lymphatic barrier to promote colorectal cancer invasion

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    Background & Aims Colorectal cancer (CRC) is highly metastatic. Metastases spread directly into local tissue or invade distant organs via blood and lymphatic vessels, but the role of lymphangiogenesis in CRC progression has not been determined. Lymphangiogenesis is induced via vascular endothelial growth factor C (VEGFC) activation of its receptor, VEGFR3; high levels of VEGFC have been measured in colorectal tumors undergoing lymphangiogenesis, and correlated with metastasis. We investigated VEGFC signaling and lymphatic barriers in human tumor tissues and mice with orthotopic colorectal tumors. Methods We performed immunohistochemical, immunoblot, and real-time PCR analyses of colorectal tumor specimens collected from patients; healthy intestinal tissues collected during surgeries of patients without CRC were used as controls. CT26 CRC cells were injected into the distal posterior rectum of BALB/c-nude mice. Mice were given injections of an antibody against VEGFR3 or an adenovirus encoding human VEGFC before orthotopic tumors and metastases formed. Lymph node, lung, and liver tissues were collected and evaluated by flow cytometry. We measured expression of vascular endothelial cadherin (CDH5) on lymphatic vessels in mice and in human intestinal lymphatic endothelial cells. Results Levels of podoplanin (a marker of lymphatic vessels), VEGFC, and VEGFR3 were increased in colorectal tumor tissues, compared with controls. Mice that expressed VEGFC from the adenoviral vector had increased lymphatic vessel density and more metastases in lymph nodes, lungs, and livers, compared with control mice. Anti-VEGR3 antibody reduced numbers of lymphatic vessels in colons and prevented metastasis. Expression of VEGFC compromised the lymphatic endothelial barrier in mice and endothelial cells, reducing expression of CDH5, increasing permeability, and increasing trans-endothelial migration by CRC cells. Opposite effects were observed in mice and cells when VEGFR3 was blocked. Conclusions VEGFC signaling via VEGFR3 promotes lymphangiogenesis and metastasis by orthotopic colorectal tumors in mice and reduces lymphatic endothelial barrier integrity. Levels of VEGFC and markers of lymphatic vessels are increased in CRC tissues from patients, compared with healthy intestine. Strategies to block VEGFR3 might be developed to prevent CRC metastasis in patients

    Применение метода долгосрочного прогнозирования водонефтяного фактора для определения максимально возможного расчётного объёма добычи нефти месторождения "Чёрный Дракон", Вьетнам

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    Objective - Although junctional adhesion molecule-A (JAM-A) has recently been implicated in leukocyte recruitment on early atherosclerotic endothelium and after reperfusion injury, its role in neointima formation after arterial injury remains to be elucidated. Methods and Results - Here we show that the genetic deletion of JAM-A in apolipoprotein E - deficient (apoE(-/-)) mice significantly reduced neointimal hyperplasia after wire injury of carotid arteries without altering medial area. This was associated with a significant decrease in neointimal macrophage content, whereas the relative content of smooth muscle cells and endothelial recovery was unaltered in JAM-A(-/-) apoE(-/-) compared with JAM-A(-/-) apoE(-/-) lesions. In carotid arteries perfused ex vivo, deficiency in JAM-A significantly impaired the recruitment of monocytes 1 week, but not 1 day, after injury. These effects were paralleled by an attenuation of monocyte arrest and transmigration on activated JAM-A(-/-) apoE(-/-) versus JAM-A(-/-) apoE(-/-) endothelial cells under flow conditions in vitro. A mechanism underlying reduced recruitment was implied by findings that the luminal expression of the arrest chemokine RANTES in injured arteries and its endothelial deposition by activated platelets in vitro were diminished by JAM-A deficiency. Conclusions - Our data provide the first evidence to our knowledge for a crucial role of JAM-A in accelerated lesion formation and monocyte infiltration in atherosclerosis-prone mice

    VE-cadherin and claudin-5: it takes two to tango

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    Endothelial barrier function requires the adhesive activity of VE-cadherin and claudin-5, which are key components of adherens and tight endothelial junctions, respectively. Emerging evidence suggests that VE-cadherin controls claudin-5 expression by preventing the nuclear accumulation of FoxO1 and -catenin, which repress the claudin-5 promoter. This indicates that a crosstalk mechanism operates between these junctional structures

    Ve-ptp modulates vascular integrity by promoting adherens junction maturation

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    Background: Endothelial cell junctions control blood vessel permeability. Altered permeability can be associated with vascular fragility that leads to vessel weakness and haemorrhage formation. In vivo studies on the function of genes involved in the maintenance of vascular integrity are essential to better understand the molecular basis of diseases linked to permeability defects. Ve-ptp (Vascular Endothelial-Protein Tyrosine Phosphatase) is a transmembrane protein present at endothelial adherens junctions (AJs). Methodology/Principal Findings: We investigated the role of Ve-ptp in AJ maturation/stability and in the modulation of endothelial permeability using zebrafish (Danio rerio). Whole-mount in situ hybridizations revealed zve-ptp expression exclusively in the developing vascular system. Generation of altered zve-ptp transcripts, induced separately by two different splicing morpholinos, resulted in permeability defects closely linked to vascular wall fragility. The ultrastructural analysis revealed a statistically significant reduction of junction complexes and the presence of immature AJs in zve-ptp morphants but not in control embryos. Conclusions/Significance: Here we show the first in vivo evidence of a potentially critical role played by Ve-ptp in AJ maturation, an important event for permeability modulation and for the development of a functional vascular system

    Stable Vascular Connections and Remodeling Require Full Expression of VE-Cadherin in Zebrafish Embryos

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    BACKGROUND: VE-cadherin is an endothelial specific, transmembrane protein, that clusters at adherens junctions where it promotes homotypic cell-cell adhesion. VE-cadherin null mutation in the mouse results in early fetal lethality due to altered vascular development. However, the mechanism of action of VE-cadherin is complex and, in the mouse embryo, it is difficult to define the specific steps of vascular development in which this protein is involved. METHODOLOGY AND PRINCIPAL FINDINGS: In order to study the role VE-cadherin in the development of the vascular system in a more suitable model, we knocked down the expression of the coding gene in zebrafish. The novel findings reported here are: 1) partial reduction of VE-cadherin expression using low doses of morpholinos causes vascular fragility, head hemorrhages and increase in permeability; this has not been described before and suggests that the total amount of the protein expressed is an important determinant of vascular stability; 2) concentrations of morpholinos which abrogate VE-cadherin expression prevent vessels to establish successful reciprocal contacts and, as a consequence, vascular sprouting activity is not inhibited. This likely explains the observed vascular hyper-sprouting and the presence of several small, collapsing vessels; 3) the common cardinal vein lacks a correct connection with the endocardium leaving the heart separated from the rest of the circulatory system. The lack of closure of the circulatory loop has never been described before and may explain some downstream defects of the phenotype such as the lack of a correct vascular remodeling. CONCLUSIONS AND SIGNIFICANCE: Our observations identify several steps of vascular development in which VE-cadherin plays an essential role. While it does not appear to regulate vascular patterning it is implicated in vascular connection and inhibition of sprouting activity. These processes require stable cell-cell junctions which are defective in absence of VE-cadherin. Notably, also partial modifications in VE-cadherin expression prevent the formation of a stable vasculature. This suggests that partial internalization or change of function of this protein may strongly affect vascular stability and organization
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