Malignant tumors of the pancreas are the fourth leading cause of cancer-related deaths. This is mainly because they are often diagnosed at a late stage. One of the challenges in diagnosing focal lesions in the pancreas is the difficulty in distinguishing them from other conditions due to the unique location and anatomy of the organ, as well as the similarity in their ultrasound characteristics.
View Article and Find Full Text PDFCrit Rev Biomed Eng
August 2023
One of the key echographic signs of focal pathology of the pancreas is the presence of formation contours and their nature. Endoscopic ultrasonography has a unique ability to visualize the echographic texture of the pancreatic parenchyma, and also allows you to assess in detail the boundaries and nature of the contours of the tumor formations of the organ due to the proximity of the ultrasound sensor. However, the differential diagnosis of focal pancreatic lesions remains a difficult clinical task due to the similarity of their echosemiotics.
View Article and Find Full Text PDFThe influence of the geometric dimensions of the cut core and the number and size of air gaps on the effective permeability was investigated. Using dimensional analysis, an equation was obtained that relates the permeability of the cut core to the simplest dimensionless combination of the mean magnetic flux length , single air gap length , the cross-sectional area of the core, and gap number . Permeability calculated from the geometric parameters of the cut core was compared with the effective permeability obtained using a two-dimensional FEMM simulation.
View Article and Find Full Text PDFSeveral recent studies suggest that systemic aging in metazoans is differentially affected by functional decline in specific tissues, such as skeletal muscle. In Drosophila, longevity appears to be tightly linked to myoproteostasis, and the formation of misfolded protein aggregates is a hallmark of senescence in aging muscle. Similarly, defective myoproteostasis is described as an important contributor to the pathology of several age-related degenerative muscle diseases in humans, e.
View Article and Find Full Text PDFFunctional redundancy is a pivotal mechanism that supports the robustness of biological systems at a molecular, cellular, and organismal level. The extensive prevalence of redundancy in molecular networks has been highlighted by recent systems biology studies; however, a detailed mechanistic understanding of redundant functions in specific signaling modules is often missing. We used affinity purification of protein complexes coupled to tandem mass spectrometry to generate a high-resolution protein interaction map of the three homologous p38 mitogen-activated protein kinases (MAPKs) in Drosophila and assessed the utility of such a map in defining the extent of common and unique functions.
View Article and Find Full Text PDFMyogenesis is a well-characterized program of cellular differentiation that is exquisitely sensitive to the extracellular milieu. Systematic characterization of the myogenic secretome (i.e.
View Article and Find Full Text PDFChromatin boundaries facilitate independent gene regulation by insulating genes from the effects of enhancers or organized chromatin. However, the mechanisms of boundary action are not well understood. To investigate whether boundary function depends on a higher order of chromatin organization, we examined the function of several Drosophila melanogaster insulators in cells with reduced chromatin-remodeling activities.
View Article and Find Full Text PDFChromatin boundaries regulate gene expression by modulating enhancer-promoter interactions and insulating transcriptional influences from organized chromatin. However, mechanistic distinctions between these two aspects of boundary function are not well understood. Here we show that SF1, a chromatin boundary located in the Drosophila Antennapedia complex (ANT-C), can insulate the transgenic miniwhite reporter from both enhancing and silencing effects of surrounding genome, a phenomenon known as chromosomal position effect or CPE.
View Article and Find Full Text PDFHypoxia and necrosis are fundamental features of glioblastoma (GBM) and their emergence is critical for the rapid biological progression of this fatal tumor; yet, underlying mechanisms are poorly understood. We have suggested that vaso-occlusion following intravascular thrombosis could initiate or propagate hypoxia and necrosis in GBM. Tissue factor (TF), the main cellular initiator of coagulation, is overexpressed in GBMs and likely favors a thrombotic microenvironment.
View Article and Find Full Text PDFBackground: Chromatin boundaries, also known as insulators, regulate gene activity by organizing active and repressive chromatin domains and modulate enhancer-promoter interactions. However, the mechanisms of boundary action are poorly understood, in part due to our limited knowledge about insulator proteins, and a shortage of standard assays by which diverse boundaries could be compared.
Results: We report here the development of an enhancer-blocking assay for studying insulator activity in Drosophila cultured cells.
Insect Biochem Mol Biol
February 2007
Identification of authenticated cuticular proteins has been based on isolation and sequencing of individual proteins extracted from cleaned cuticles. These data facilitated classification of sequences from conceptual translation of cDNA or genomic sequences. The question arises whether such putative cuticular proteins actually are incorporated into the cuticle.
View Article and Find Full Text PDFHypoxia is a universal feature of solid tumors that arises as the tumor mass outgrows stromal vascular supply. Hypoxia-inducible factor (HIF)-1, a transcription factor upregulated in hypoxia, orchestrates a range of adaptive responses that allow tumor cells to survive oxygen deprivation. Important information regarding the role of HIF-1 in tumor biology was gained from tumor biopsy studies in which HIF-1 expression was strongly associated with poor patient prognosis, and from animal studies in which genetic ablation of HIF-1 signaling retarded tumor growth.
View Article and Find Full Text PDFHypoxia develops in the majority of solid tumors due to the inability of the existing vascular system to supply the growing tumor mass with adequate amounts of oxygen. A large body of clinical evidence suggests that intratumoral hypoxia correlates with the elevated aggressive behavior of cancer cells and their resistance to therapy, leading to poor patient prognoses. A heterodimeric transcription factor, hypoxia inducible factor-1 (HIF-1), has been shown to orchestrate a large number of molecular events required for the adaptation of tumor cells to hypoxia.
View Article and Find Full Text PDFThe intrinsic enhancer-promoter specificity and chromatin boundary/insulator function are two general mechanisms that govern enhancer trafficking in complex genetic loci. They have been shown to contribute to gene regulation in the homeotic gene complexes from fly to mouse. The regulatory region of the Scr gene in the Drosophila Antennapedia complex is interrupted by the neighboring ftz transcription unit, yet both genes are specifically activated by their respective enhancers from such juxtaposed positions.
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