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F Escaig

Publications and source records attributed to F Escaig.

10 recordsLinked to original sources
PubMed1992

Mapping of intracellular halogenous molecules by low and high resolution SIMS microscopy.

The subcellular distribution of halogenous molecules has been studied by SIMS microscopy in cultured cells of a human breast carcinoma (MCF-7 cell line). Two instruments of microanalysis were used. A low lateral resolution ion microscope (SMI 300 CAMECA) and a prototype scanning ion microscope equipped with a cesium gun that gives high lateral resolution images. This apparatus has been developed by G Slodzian, in Onera Laboratories (Office National d'Etudes et de Recherches Aérospatiales). Molecules studied by low lateral resolution ion microscope were halogenous steroids: fluorometholone, triamcinolone, bromocriptine and bromoandrosterone. Analytical images show that the first two compounds are mainly localized in the nuclear structure of MCF-7 cells whereas the last two molecules are localized in cytoplasm of these cells. Images were obtained with a resolution of 1 micron. With the scanning ion microscope, it is now possible to obtain images at the ultrastructural level. Four analytical images can be simultaneously obtained by a single scan of the imaged area, corresponding to a depth of erosion of the section of ten nm. The intranuclear distributions of three pyrimidine analogs, 5-bromo-2'-deoxyuridine, 5-iodo-2'-deoxyuridine and 5-fluorouracil have been studied in phase S and M of MCF-7 cells and these images have been compared to the distribution of sulfur, nitrogen and phosphorus. All these images have been obtained with a lateral resolution better than 100 nm.

Adrenal Cortex Hormones↗
PubMed1992

Subcellular localization of two neurotropic drugs in three varieties of central nervous system cells by secondary ion mass spectroscopy (SIMS) microscopy.

The intracellular localization of two neurotropic drugs, flunitrazepam (benzodiazepine) and triflupromazine (phenothiazine), was studied by secondary ion mass spectrometry microscopy (SIMS) in three varieties of cells. The images of the intracellular distributions of the two drugs are easily obtained by selecting the fluorine atom of the molecules. These images show that the drug from the benzodiazepine group is mainly located in the nuclei, whereas the phenothiazine is exclusively located inside the cytoplasm.

Animals↗
PubMed1992

Preservation of the diffusible cations for secondary ion mass spectrometry. II. Artefacts in material embedded in araldite or melamine.

Flotation on hot water (about 60 degrees C) which is frequently employed to stretch semithin sections on substrates for SIMS (secondary ion mass spectrometry) microscopy, is the cause of numerous artefacts. In the case of epoxy resin-embedded tissue, one observes loss of potassium and sodium and accumulation of calcium. The relative contrast of cell nuclei in the ionic images, is rapidly affected by these ion migrations. After prolonged contact with hot water, tissue becomes uniformly emissive. In the case of hydrosoluble resin-embedded tissue, potassium and sodium do not appear to be affected by the action of water, which suggests that they are covalently bound with chelating sites buried beneath the layer of water bound to the surface of the macromolecules. Calcium accumulates, probably on widely exposed anionic sites. Moreover, the domains observed in hydrosoluble resin-embedded tissue shrink differently according to the proportion of water removed by melamine; this can provide interesting information on the initial equilibrium between water, ion sand macromolecules. Our results seem to support the assumption that bound water should play an important role in the preservation of both macromolecular architecture and ion distributions.

Animals↗
PubMed1992

[Localization of two neurotropic molecules in cultured glial cells by ion microscopy].

The intracellular localization of two families of neurotropic drugs: flunitrazepam and flurazepam (benzodiazepine), triflupromazine and trifluoperazine (phenothiazine) has been studied by ion microscopy. The molecules have been incubated with C6 glioblastoma cells from rat origin and with astroglial primary cultures. The images of the intracellular distributions of the two drugs are easily obtained by selecting the fluorine atom of the molecules. The images obtained show that flunitrazepam and flurazepam, two drugs of the benzodiazepine group are mainly located to the nuclei, whereas triflupromazine and trifluoperazine, two phenothiazines are exclusively located inside the cytoplasm.

Animals↗
PubMed1990

Intracellular localization of drugs in cultured tumor cells by ion microscopy and image processing.

Several drugs, containing a halogen atom, F or Br, that are being used in antiviral or anticancer therapy, were studied for their localization in cultured cells by ion microanalysis. The association allows to reduce the exposure time to define the intracellular localization of the studied element. The topography of the cells is given by the image of the polyatomic ion 26CN-. The image of the distribution of 81Br- or 19F-, coded in another color scale, can be superimposed, giving a polychromic image of the cell, thus showing the intracellular localization of the compound. MCF-7 tumor cells were cultured in the presence of pyrimidine derivatives. 5-Bromo-2'-deoxyuridine (BUdR) and 5-trifluorothymidine (F3TdR) were localized in the nucleus, 5-fluoro-2'-deoxyuridine (FUdR) in the nucleus and only in some nucleoli. The method is simple and rapid, as compared with techniques using radiolabeled compounds, or with immunocytochemical techniques. It is possible to observe two different compounds in the same cell. It could be applied to other compounds containing a halogen atom.

Bromodeoxyuridine↗
PubMed1990

[The detection of viral antigens and ribosomal RNA in cells by using low-temperature media].

A post-embedding technique for immunocytochemical analysis at the ultrastructural level was used to detect and localize HIV antigens on ultrathin sections of Lowicryl-embedded HIV-infected cells. A genomic probe containing ribosomal sequences and labeled with biotin was used to hybridize rRNA molecules in sections of animal cells embedded in Lowicryl. The method presently described offers the possibility to detect rapidly and precisely ribosomal gene expression and viral proteins at the ultrastructural level.

Acrylic Resins↗
PubMed1979

[Autoradiographic study of the activity of odontoblasts and secretory ameloblasts in the rat incisor: changes induced by vinblastine].

An autoradiographic study conducted on the rat incisor showed the presence 4 hours after (3H) proline injection, of 25-30% of the grains on the secreting cells and 70 to 75% on the extracellular matrics. The simultaneous injection of vinblastine sulphate reversed these percentages to 75-80% on the cellular level and 25-25% on the matrics. The vinblastine therefore inhibited the secretory processes of these cell types. On the other hand, due to the alkaloid, the number of grains present increased over the ameloblasts and principally over the intercellular spaces. The effects of these secretion and permeability variations suggested that a flow of precursor rich material reached the epithelial layer whatever the state of ameloblast activity.

Ameloblasts↗
PubMed1976

[Acid mucopolysaccharide detection on ultra-thin sections by alcian blue in dental tissues embedded in Epon].

Ultra-thin sections of dental tissues, fixed in glutaraldehyde and osmium tetroxide, embedded without previous demineralization in Epon, were contrasted the grids with an alcian blue solution after previous oxidation periodic acid or hydrogen peroxide. Correlations with histochemical results obtained with the optical microscope, other results obtained with ruthenium red and phosphotungstic acid and controls made after enzymatic digestion with chondroitinase AC suggest that this technique is specific for the detection of acid mucopolysaccharides in those calcified tissues studied.

Animals↗