3,703 research outputs found
Pathogenesis of Abdominal Aortic Aneurysms: Role of Nicotine and Nicotinic Acetylcholine Receptors
Inflammation, proteolysis, smooth muscle cell apoptosis, and angiogenesis have been implicated in the pathogenesis of abdominal aortic aneurysms (AAAs), although the well-defined initiating mechanism is not fully understood. Matrix metalloproteinases (MMPs) such as MMP-2 and -9 and other proteinases degrading elastin and extracellular matrix are the critical pathogenesis of AAAs. Among the risk factors of AAAs, cigarette smoking is an irrefutable one. Cigarette smoke is practically involved in various aspects of the AAA pathogenesis. Nicotine, a major alkaloid in tobacco leaves and a primary component in cigarette smoke, can stimulate the MMPs expression by vascular SMCs, endothelial cells, and inflammatory cells in vascular wall and induce angiogenesis in the aneurysmal tissues. However, for the inflammatory and apoptotic processes in the pathogenesis of AAAs, nicotine seems to be moving in just the opposite direction. Additionally, the effects of nicotine are probably dose dependent or associated with the exposure duration and may be partly exerted by its receptors—nicotinic acetylcholine receptors (nAChRs). In this paper, we will mainly discuss the pathogenesis of AAAs involving inflammation, proteolysis, smooth muscle cell apoptosis and angiogenesis, and the roles of nicotine and nAChRs
7-Benzyl-3-(4-fluorophenyl)-2-(pyrrolidin-1-yl)-5,6,7,8-tetrahydropyrido[4′,3′:4,5]thieno[2,3-d]pyrimidin-4(3H)-one
In the title compound, C26H25FN4OS, the thienopyrimidine fused-ring system is close to planar (r.m.s. deviation = 0.066 Å), with a maximum deviation of 0.1243 (17) Å for the N atom adjacent to the carbonyl group. This ring system forms dihedral angles of 67.5 (1) and 88.9 (1) ° with the adjacent six-membered rings. Intermolecular C—H⋯O hydrogen bonding and C—H⋯π interactions help to stabilize the crystal structure
Genome-wide search for the genes accountable for the induced resistance to HIV-1 infection in activated CD4+ T cells: apparent transcriptional signatures, co-expression networks and possible cellular processes
BACKGROUND: Upon co-stimulation with CD3/CD28 antibodies, activated CD4 + T cells were found to lose their susceptibility to HIV-1 infection, exhibiting an induced resistant phenotype. This rather unexpected phenomenon has been repeatedly confirmed but the underlying cell and molecular mechanisms are still unknown. METHODS: We first replicated the reported system using the specified Dynal beads with PHA/IL-2-stimulated and un-stimulated cells as controls. Genome-wide expression and analysis were then performed by using Agilent whole genome microarrays and established bioinformatics tools. RESULTS: We showed that following CD3/CD28 co-stimulation, a homogeneous population emerged with uniform expression of activation markers CD25 and CD69 as well as a memory marker CD45RO at high levels. These cells differentially expressed 7,824 genes when compared with the controls on microarrays. Series-Cluster analysis identified 6 distinct expression profiles containing 1,345 genes as the representative signatures in the permissive and resistant cells. Of them, 245 (101 potentially permissive and 144 potentially resistant) were significant in gene ontology categories related to immune response, cell adhesion and metabolism. Co-expression networks analysis identified 137 “key regulatory” genes (84 potentially permissive and 53 potentially resistant), holding hub positions in the gene interactions. By mapping these genes on KEGG pathways, the predominance of actin cytoskeleton functions, proteasomes, and cell cycle arrest in induced resistance emerged. We also revealed an entire set of previously unreported novel genes for further mining and functional validation. CONCLUSIONS: This initial microarray study will stimulate renewed interest in exploring this system and open new avenues for research into HIV-1 susceptibility and its reversal in target cells, serving as a foundation for the development of novel therapeutic and clinical treatments
Self-organized Voids Revisited: Experimental Verification of the Formation Mechanism*
In this paper, several experiments were conducted to further clarify the
formation mechanism of self organized void array induced by a single laser
beam, including energy-related experiments, refractive-index-contrast-related
experiments, depth-related experiments and effective-numerical-aperture
experiment. These experiments indicate that the interface spherical aberration
is indeed responsible for the formation of void arrays
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