Search results for "Fluorescence"

Defining Ewing and Ewing-like small round cell tumors (SRCT): The need for molecular techniques in their categorization and differential diagnosis. A…

2016

Abstract Background Differentiation of Ewing sarcoma family of tumors (ESFT) and Ewing-like tumors remains problematic. Certain ESFT with morphological and immunohistochemical (IHC) profiles lack the EWSR1-ETS transcript. To improve diagnostic accuracy we investigated the presence of several specific transcripts in 200 small round cell tumors (SRCT) displaying ESFT morphology and immunophenotype in which EWSR1 FISH analysis was non-informative or negative. Design 200 tumors (formalin-fixed, paraffin-embedded) were analyzed by RT-PCR. All tumors were tested for EWSR1-ETS , EWSR1 / WT1 , PAX3 / 7-FOX01 or SYT / SSX transcripts, and the negative tumors were subsequently analyzed for CIC / DUX4…

A survey of clearing techniques for 3D imaging of tissues with special reference to connective tissue

2016

AbstractFor 3-dimensional (3D) imaging of a tissue, 3 methodological steps are essential and their successful application depends on specific characteristics of the type of tissue. The steps are 1° clearing of the opaque tissue to render it transparent for microscopy, 2° fluorescence labeling of the tissues and 3° 3D imaging. In the past decades, new methodologies were introduced for the clearing steps with their specific advantages and disadvantages. Most clearing techniques have been applied to the central nervous system and other organs that contain relatively low amounts of connective tissue including extracellular matrix. However, tissues that contain large amounts of extracellular mat…

2021

Abstract Background Gastric inflammation is a major risk factor for gastric cancer. Current endoscopic methods are not able to efficiently detect and characterize gastric inflammation, leading to a sub-optimal patients’ care. New non-invasive methods are needed. Reflectance mucosal light analysis is of particular interest in this context. The aim of our study was to analyze reflectance light and specific autofluorescence signals, both in humans and in a mouse model of gastritis. Methods We recruited patients undergoing gastroendoscopic procedure during which reflectance was analysed with a multispectral camera. In parallel, the gastritis mouse model of Helicobacter pylori infection was used…

Kupffer Cell and Monocyte-Derived Macrophage Identification by Immunofluorescence on Formalin-Fixed, Paraffin-Embedded (FFPE) Mouse Liver Sections

2020

Kupffer cells are the liver-resident macrophages and represent the first line of defense between the pathogens circulating from the intestines through the portal vein and systemic circulation. Recent works have highlighted the complex heterogeneity of macrophage functions and origins, thus raising awareness on the need for a better characterization of macrophage populations. The immunohistochemistry method here described, allows for a rapid distinction between Kupffer cells and monocyte-derived macrophages present on formalin-fixed, paraffin-embedded mouse liver samples. This protocol has been optimized for its reproducibility, reliability, and simplicity.

Eomes broadens the scope of CD8 T-cell memory by inhibiting apoptosis in cells of low affinity.

2020

The memory CD8 T-cell pool must select for clones that bind immunodominant epitopes with high affinity to efficiently counter reinfection. At the same time, it must retain a level of clonal diversity to allow recognition of pathogens with mutated epitopes. How the level of diversity within the memory pool is controlled is unclear, especially in the context of a selective drive for antigen affinity. We find that preservation of clones that bind the activating antigen with low affinity depends on expression of the transcription factor Eomes in the first days after antigen encounter. Eomes is induced at low activating signal strength and directly drives transcription of the prosurvival protein…

External Influences on Invertebrate Brain Histamine and Related Compounds via an Automated Derivatization Method for Capillary Electrophoresis.

2017

8 pages; International audience; Histamine has been shown to modulate visual system and photic behavior in arthropods. However, few methods are available for the direct quantification of histamine and its precursor and metabolites in arthropod brain. In this work, a method for the separation of histamine, its precursor histidine, and its metabolite N-methyl-histamine from brain extracts of a freshwater crustacean has been developed using capillary electrophoresis with laser-induced fluorescence detection. Molecules were tagged on their primary amine function with naphthalene-2,3-dicarboxaldehyde, but derivatized histamine and N-methyl-histamine exhibited poor stability in contrast to deriva…

Evolutionary insight on localization of 18S, 28S rDNA genes on homologous chromosomes in Primates genomes

2018

Abstract We explored the topology of 18S and 28S rDNA units by fluorescence in situ hybridization (FISH) in the karyotypes of thirteen species representatives from major groups of Primates and Tupaia minor (Günther, 1876) (Scandentia), in order to expand our knowledge of Primate genome reshuffling and to identify the possible dispersion mechanisms of rDNA sequences. We documented that rDNA probe signals were identified on one to six pairs of chromosomes, both acrocentric and metacentric ones. In addition, we examined the potential homology of chromosomes bearing rDNA genes across different species and in a wide phylogenetic perspective, based on the DAPI-inverted pattern and their synteny t…

Taking up the cudgels for the traditional reactive oxygen and nitrogen species detection assays and their use in the cardiovascular system

2017

Reactive oxygen and nitrogen species (RONS such as H2O2, nitric oxide) confer redox regulation of essential cellular functions (e.g. differentiation, proliferation, migration, apoptosis), initiate and catalyze adaptive stress responses. In contrast, excessive formation of RONS caused by impaired break-down by cellular antioxidant systems and/or insufficient repair of the resulting oxidative damage of biomolecules may lead to appreciable impairment of cellular function and in the worst case to cell death, organ dysfunction and severe disease phenotypes of the entire organism. Therefore, the knowledge of the severity of oxidative stress and tissue specific localization is of great biological …

Viral Bcl2s' transmembrane domain interact with host Bcl2 proteins to control cellular apoptosis

2020

© The Author(s) 2020.

Warhead Reactivity Limits the Speed of Inhibition of the Cysteine Protease Rhodesain.

2021

Viral and parasitic pathogens rely critically on cysteine proteases for host invasion, replication, and infectivity. Their inhibition by synthetic inhibitors, such as vinyl sulfone compounds, has emerged as a promising treatment strategy. However, the individual reaction steps of protease inhibition are not fully understood. Using the trypanosomal cysteine protease rhodesain as a medically relevant target, we design photoinduced electron transfer (PET) fluorescence probes to detect kinetics of binding of reversible and irreversible vinyl sulfones directly in solution. Intriguingly, the irreversible inhibitor, apart from its unlimited residence time in the enzyme, reacts 5 times faster than …