The focus of this review is to provide an overview of the current state of knowledge of molecular mechanisms/processes that control differentiation of vascular smooth muscle cells (SMC) during normal development and maturation of the vasculature, as well as how these mechanisms/processes are altered in vascular injury or disease. A major challenge in understanding differentiation of the vascular SMC is that this cell can exhibit a wide range of different phenotypes at different stages of development, and even in adult organisms the cell is not terminally differentiated. Indeed, the SMC is capable of major changes in its phenotype in response to changes in local environmental cues including growth factors/inhibitors, mechanical influences, cell-cell and cell-matrix interactions, and various inflammatory mediators. There has been much progress in recent years to identify mechanisms that control expression of the repertoire of genes that are specific or selective for the vascular SMC and required for its differentiated function. One of the most exciting recent discoveries was the identification of the serum response factor (SRF) coactivator gene myocardin that appears to be required for expression of many SMC differentiation marker genes, and for initial differentiation of SMC during development. However, it is critical to recognize that overall control of SMC differentiation/maturation, and regulation of its responses to changing environmental cues, is extremely complex and involves the cooperative interaction of many factors and signaling pathways that are just beginning to be understood. There is also relatively recent evidence that circulating stem cell populations can give rise to smooth muscle-like cells in association with vascular injury and atherosclerotic lesion development, although the exact role and properties of these cells remain to be clearly elucidated. The goal of this review is to summarize the current state of our knowledge in this area and to attempt to identify some of the key unresolved challenges and questions that require further study.
The historical view of vascular smooth muscle cells (VSMCs) in atherosclerosis is that aberrant proliferation of VSMCs promotes plaque formation, but that VSMCs in advanced plaques are entirely beneficial, for example preventing rupture of the fibrous cap. However, this view has been based on ideas that there is a homogenous population of VSMCs within the plaque, that can be identified separate from other plaque cells (particularly macrophages) using standard VSMC and macrophage immunohistochemical markers. More recent genetic lineage tracing studies have shown that VSMC phenotypic switching results in less-differentiated forms that lack VSMC markers including macrophage-like cells, and this switching directly promotes atherosclerosis. In addition, VSMC proliferation may be beneficial throughout atherogenesis, and not just in advanced lesions, whereas VSMC apoptosis, cell senescence, and VSMC-derived macrophage-like cells may promote inflammation. We review the effect of embryological origin on VSMC behavior in atherosclerosis, the role, regulation and consequences of phenotypic switching, the evidence for different origins of VSMCs, and the role of individual processes that VSMCs undergo in atherosclerosis in regard to plaque formation and the structure of advanced lesions. We think there is now compelling evidence that a full understanding of VSMC behavior in atherosclerosis is critical to identify therapeutic targets to both prevent and treat atherosclerosis.
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The Smooth Transition Strategy (STS) guidance note, developed by the CDP Secretariat, is in response to the recommendations of the General Assembly and the follow-up actions proposed by the CDP on strengthening smooth transition measures and dedicated capacity building to help graduating and graduated countries prepare their STS. It also informs graduating least developed countries (LDCs) and their development partners about the best way to assist such countries following graduation.
The State Botanical Garden of Georgia has been propagating smooth coneflower since 1999 for reintroduction onto the Chattahoochee National Forest and for educational gardens at their gardens in Athens, Georgia and at Tallulah Gorge State Park. Two additional education gardens are being planned, one at the USFS Visitor Center in Clayton, Georgia and one at Stephens County, Georgia. Also, the Atlanta Botanical Garden cultivates this plant for educational purposes.
FinishesGlen-Gery extruded bricks are available in a variety of textures. The textures include smooth, velour, bar, rug, matt, paper cut, scored, rockface, slurry and sand finishes. The availability of a particular finish is usually dependent on the specific product. Certain finishes (i.e. bark) are not available on shapes.
Unlike the very similar Rough Earthsnake, the Smooth Earthsnake is smooth (or weakly keeled) scales and occurs across most of Tennessee. Two subspecies are found in the state: Western Smooth Earthsnake (V. v. elegans), which occurs in West Tennessee and northwest Middle TN, and Eastern Smooth Earthsnake, which occurs in East Tennessee except the northeast corner.
Description: A small, plain-looking snake (7.0 to 10.0 inches in length) with a narrow head, 6 labial scales (upper lip), and loreal scales (in front of eyes) that are horizontal and touching the eye. Eastern Smooth subspecies is mostly gray or light brownish-gray, with tiny black dots scattered on the back, and smooth scales (except on back near tail).
Background: The thin and small smooth greensnake is irregularly distributed in Connecticut. It is easily distinguished from the other native snakes by its striking solid green coloration. This state species of special concern is facing the loss of its specialized habitat from the Connecticut landscape due to development and forest succession. In addition, populations are threatened by effects from insecticide spraying (contaminated prey). Mowing (lawns and hayfields) and farm equipment also cause problems by reducing vegetation height and causing direct mortality. Road mortality is another concern for this species, as well as predation by house cats.
Populations of smooth greensnakes are sporadic in location and abundance in Connecticut, leading to a general scarcity. Some sites may have larger populations, while others have only a few individuals. Population declines have occurred in areas where forested habitat has reoccupied open, grassy areas. Populations can also fluctuate with prey (insect) availability and abundance.
In Connecticut, smooth greensnakes are found mostly in the eastern half of the state where suitable habitat exists. They are rare in the southwestern Connecticut and only occasionally found in the northwestern portion of the state.
Description: Small and delicate, this snake ranges from 12 to 25 inches in length. Its dorsal (back) coloration is solid green with unkeeled (smooth) scales, while the underside is yellow or off-white. Juveniles resemble adults but are more olive-green in color.
Habitat and Diet: Smooth greensnakes favor moist, open habitats, such as old fields, meadows, pastures, fens, coastal grasslands, and edges of wetlands. Occasionally, this snake may inhabit sparsely forested areas with scattered shrubs and trees, such as mountaintop balds. Rural, undisturbed locations appear to be preferred, but smooth greensnakes have been found in urban and suburban areas as well. Greensnakes can be found basking on rocks, logs, or other debris. Sometimes, this snake may be absent from seemingly suitable habitat.
Shortly after death, this snake loses its green coloration and turns bright blue.The smooth greensnake is often confused with its similarly-colored close relative, the rough greensnake. However, the rough greensnake does not occur in Connecticut but in the southeastern United States. This species is considered to be more arboreal than terrestrial. It also has keeled scales (raised ridge in the center of each scale).
Take the time to learn about, understand, and respect this vitally important reptile, and share your knowledge with others. If you encounter a smooth greensnake, observe it from a distance and allow it to go on its way. All snakes will retreat from humans if given a chance. You should not try to agitate it by getting too close or handling it. Although docile, it may try to bite. Never try to collect a greensnake as a pet. Not only is this illegal, but this snake does not survive well in captivity.
Do NOT attempt to kill any smooth greensnakes under any circumstances as this is an illegal action. Greensnakes are protected by Connecticut's Endangered Species Act and persons who kill or collect this special concern snake could be faced with fines or legal action. If you see or know of any suspicious or neglectful activity directed towards these snakes, you can report violators to the DEEP at the 24-hour, toll-free TIP hotline (800-842-HELP) or DEEP Dispatch at 860-424-3333.
Be a strong proponent of conserving greensnake habitats. If your property has habitat containing this snake, consider appropriate pasture management protocols. Be cautious of wildlife when mowing or using agricultural equipment, and consider letting some areas remain unmowed. It you must use any pesticides or herbicides, consider using organic varieties that will not harm beneficial, native wildlife. Preserving pastures and fields through agricultural easements also will benefit smooth greensnakes. 041b061a72