467 research outputs found
L-NAME treatment in pigs
Abstract only availableNω-nitro-L-arginine-methyl-ester (L-NAME) inhibits the enzyme nitric oxide synthase (NOS) which generates the physiologic messenger gas, nitric oxide (NO). In addition to its role as a vasodilator NO inhibits inflammation and vascular smooth muscle cell proliferation. It was shown recently that rats fed L-NAME contain evidence of inflammation and increased collagen in their coronary vasculature when compared with control rats. We hypothesized that L-NAME treatment will cause inflammation and an increase in collagen in the coronary vasculature of pigs compared with control pigs. To test this hypothesis we have four pigs, two received L-NAME in their drinking water and two did not. We have samples of the left ventricle (LV), right ventricle (RV), and left anterior descending (LAD), left circumflex (LCX), and right (RCA) coronary arteries of the heart. Similar to studies in the rat, we will stain these samples for monocyte chemoattractant protein-1 (MCP-1), a marker of inflammation; alpha smooth muscle actin (αSMA), a marker of vascular smooth muscle, and picrosirius red (PSR) a marker of collagen. We will photograph sections of the coronary vasculature stained with these markers and use a computer image analysis system to count the amount of MCP-1, vascular smooth muscle, and collagen. Preliminary results suggest that we have insufficient statistical power to show differences in the parameters measured and need to examined greater numbers of animals.Louis Stokes Missouri Alliance for Minority Participatio
Behaviors of Adult \u3ci\u3eAgrilus Planipennis\u3c/i\u3e (Coleoptera: Buprestidae)
A 2-year study was conducted in Canada (2003) and the United States (2005) to better understand searching and mating behaviors of adult Agrilus planipennis Fairmaire. In both field and laboratory, adults spent more time resting and walking than feeding or flying. The sex ratio in the field was biased towards males, which tended to hover around trees, likely looking for mates. There was more leaf feeding damage within a tree higher in the canopy than in the lower canopy early in the season, but this difference disappeared over time. In choice experiments, males attempted to mate with individuals of both sexes, but they landed more frequently on females than on males. A series of sexual behaviors was observed in the laboratory, including: exposure of the ovipositor/genitalia, sporadic jumping by males, attempted mating, and mating. Sexual behaviors were absent among 1-3 day-old beetles, but were observed regularly in 10-12 day-old beetles. Females were seen exposing their ovipositor, suggestive of pheromone-calling behavior. No courtship was observed prior to mating. Hovering, searching, and landing behaviors suggest that beetles most likely rely on visual cues during mate finding, although host-plant volatiles and/or pheromones might also be involved
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Diverse diazotrophs are present on sinking particles in the North Pacific Subtropical Gyre.
Sinking particles transport carbon and nutrients from the surface ocean into the deep sea and are considered hot spots for bacterial diversity and activity. In the oligotrophic oceans, nitrogen (N2)-fixing organisms (diazotrophs) are an important source of new N but the extent to which these organisms are present and exported on sinking particles is not well known. Sinking particles were collected every 6 h over a 2-day period using net traps deployed at 150 m in the North Pacific Subtropical Gyre. The bacterial community and composition of diazotrophs associated with individual and bulk sinking particles was assessed using 16S rRNA and nifH gene amplicon sequencing. The bacterial community composition in bulk particles remained remarkably consistent throughout time and space while large variations of individually picked particles were observed. This difference suggests that unique biogeochemical conditions within individual particles may offer distinct ecological niches for specialized bacterial taxa. Compared to surrounding seawater, particle samples were enriched in different size classes of globally significant N2-fixing cyanobacteria including Trichodesmium, symbionts of diatoms, and the unicellular cyanobacteria Crocosphaera and UCYN-A. The particles also contained nifH gene sequences of diverse non-cyanobacterial diazotrophs suggesting that particles could be loci for N2 fixation by heterotrophic bacteria. The results demonstrate that diverse diazotrophs were present on particles and that new N may thereby be directly exported from surface waters on sinking particles
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Rain impacts on CO2 exchange in the western equatorial Pacific Ocean
The ocean plays a major role in the global carbon cycle through the atmosphere-ocean partitioning of atmospheric carbon dioxide. Rain alters the physics and carbon chemistry at the ocean surface to increase the amount of CO2 taken up by the ocean. This paper presents the results of a preliminary study wherein rain measurements in the western equatorial Pacific are used to determine the enhanced transfer, chemical dilution and deposition effects of rain on air-sea CO2 exchange. Including these processes, the western equatorial Pacific CO2 flux is modified from an ocean source of +0.019 mol CO2 m−2 yr−1 to an ocean sink of −0.078 mol CO2 m−2 yr−1. This new understanding of rain effects changes the ocean's role in the global carbon budget, particularly in regions with low winds and high precipitation
Anti-atherogenic function of LPL in human and porcine coronary endothelial cells [abstract]
Abstract only availableMultiple epidemiological studies concluded that lipoprotein lipase (LPL) function is inversely related to the incidence and severity of coronary artery disease. There is debate, however, because those seeking to identify the responsible mechanisms have reported higher than normal levels of LPL in the arteries of diseased mouse models. This confusion could be clarified by beginning to identify the LPL responses in pigs as a large animal model and determining the phenotypic effects of experimentally altering LPL on cultured endothelial cells and isolated vascular tissue. PURPOSE: We tested the hypothesis that LPL activity regulates the expression of thrombospondin-1 (TSP-1), eNOS, VCAM1, and the PPAR promoter activity in endothelial cells. METHODS: LPL activity and protein were measured in the plasma and heart of pigs fed a normal or high fat diet. The cellular effects of changing LPL activity were determined in primary porcine and human endothelial cells. Studies of VCAM1 were performed in cultured cells and isolated aortic segments. Northern and Western blots were used for mRNA and protein measurements, respectively. RESULTS: LPL-dependent lipolysis of VLDL suppressed TSP-1 expression several fold in endothelial cells (PNational Institutes of Healt
Behaviors of adult agrilus planipennis (Coleoptera: Buprestidae)
AbstrAct A 2-year study was conducted in Canada (2003) and the United States (2005) to better understand searching and mating behaviors of adult Agrilus planipennis Fairmaire. In both field and laboratory, adults spent more time resting and walking than feeding or flying. The sex ratio in the field was biased towards males, which tended to hover around trees, likely looking for mates. There was more leaf feeding damage within a tree higher in the canopy than in the lower canopy early in the season, but this difference disappeared over time. In choice experiments, males attempted to mate with individuals of both sexes, but they landed more frequently on females than on males. A series of sexual behaviors was observed in the laboratory, including: exposure of the ovipositor/ genitalia, sporadic jumping by males, attempted mating, and mating. Sexual behaviors were absent among 1-3 day-old beetles, but were observed regularly in 10-12 day-old beetles. Females were seen exposing their ovipositor, suggestive of pheromone-calling behavior. No courtship was observed prior to mating. Hovering, searching, and landing behaviors suggest that beetles most likely rely on visual cues during mate finding, although host-plant volatiles and/or pheromones might also be involved
An 11-Year Global Gridded Aerosol Optical Thickness Reanalysis (v1.0) for Atmospheric and Climate Sciences
While stand alone satellite and model aerosol products see wide utilization, there is a significant need in numerous atmospheric and climate applications for a fused product on a regular grid. Aerosol data assimilation is an operational reality at numerous centers, and like meteorological reanalyses, aerosol reanalyses will see significant use in the near future. Here we present a standardized 2003–2013 global 1 × 1 ◦ and 6-hourly modal aerosol optical thickness (AOT) reanalysis product. This data set can be applied to basic and applied Earth system science studies of significant aerosol events, aerosol impacts on numerical weather prediction, and electro-optical propagation and sensor performance, among other uses. This paper describes the science of how to develop and score an aerosol reanalysis product. This reanalysis utilizes a modified Navy Aerosol Analysis and Prediction System (NAAPS) at its core and assimilates quality controlled retrievals of AOT from the Moderate Resolution Imaging Spectroradiometer (MODIS) on Terra and Aqua and the Multi-angle Imaging SpectroRadiometer (MISR) on Terra. The aerosol source functions, including dust and smoke, were regionally tuned to obtain the best match between the model fine- and coarse-mode AOTs and the Aerosol Robotic Network (AERONET) AOTs. Other model processes, including deposition, were tuned to minimize the AOT difference between the model and satellite AOT. Aerosol wet deposition in the tropics is driven with satellite-retrieved precipitation, rather than the model field. The final reanalyzed fine- and coarse-mode AOT at 550 nm is shown to have good agreement with AERONET observations, with global mean root mean square error around 0.1 for both fine- and coarse-mode AOTs. This paper includes a discussion of issues particular to aerosol reanalyses that make them distinct from standard meteorological reanalyses, considerations for extending such a reanalysis outside of the NASA A-Train era, and examples of how the aerosol reanalysis can be applied or fused with other model or remote sensing products. Finally, the reanalysis is evaluated in comparison with other available studies of aerosol trends, and the implications of this comparison are discussed
Continuous real time ex vivo epifluorescent video microscopy for the study of metastatic cancer cell interactions with microvascular endothelium
Recent studies suggest that only endothelium-attached malignant cells are capable of giving rise to hematogenous cancer metastases. Moreover, tumor cell adhesion to microvascular endothelium could be crucial in metastasis predilection to specific organs or tissues. However, the existing in vitro and in vivo techniques do not provide for sufficient delineation of distinct stages of a dynamic multi-step intravascular adhesion process. Here we report the development of an experimental system allowing for prolonged continuous ex vivo real-time observation of malignant cell adhesive interactions with perfused microvessels of a target organ in the context of its original tissue. Specifically, the vasculature of excised dura mater perfused with prostate cancer cells is described. An advantage of this technique is that selected fluorescently labeled tumor cells can be followed along identified vascular trees across the entire tissue specimen. The techniques provide for superior microvessel visualization and allow for uninterrupted monitoring and video recording of subsequent adhesion events such as rolling, docking (initial reversible adhesion), locking (irreversible adhesion), and flattening of metastatic cancer cells within perfused microvasculature on a single cell level. The results of our experiments demonstrate that intravascular adhesion of cancer cells differs dramatically from such of the leukocytes. Within dura microvessels perfused at physiological rate, non-interacting, floating, tumor cells move at velocities averaging 7.2×10 3  μm/s. Some tumor cells, similarly to leukocytes, exhibit rolling-like motion patterns prior to engaging into more stable adhesive interactions. In contrast, other neoplastic cells became stably adhered without rolling showing a rapid reduction in velocity from 2×10 3 to 0 μm/s within fractions of a second. The experimental system described herein, while developed originally for studying prostate cancer cell interactions with porcine dura mater microvasculature, offers great flexibility in adhesion experiments design and is easily adapted for use with a variety of other tissues including human.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/42585/1/10585_2004_Article_5120583.pd
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