摘要:

Summary—Monolayer cultures of human fibroblasts were incubated for 24 h with14C‐arginine and observed by means of SIMS microscopy (ion microscopy). Carbon 14 imaging showed the intracellular distribution of labelled arginine which featured high nuclear incorporation. The local concentration of this amino acid in different cells and intracellular structures was assessed through local isotopic14C/12C ratio measurement. This relates the signal intensity of the labelling isotope carbon 14 to that of the corresponding natural isotope (carbon 12) of known tissular concentration. Using this method we were able to measure minor variations in the molecular concentration of arginine (expressed as μmol/g of tissue) between different fibroblasts. Results of this study indicate that SIMS microscopy is well adapted to carbon 14 detection and can provide quantitative maps of the cellular and subcellular distribution of14C‐labelled mol

ISSN:0248-4900    

DOI:10.1016/0248-4900(92)90012-P

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

Summary—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 μm. 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 re

ISSN:0248-4900    

DOI:10.1016/0248-4900(92)90013-Q

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

Summary—The intracellular localization of two neurotropic drugs, flunitrazepan (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 cytoplas

ISSN:0248-4900    

DOI:10.1016/0248-4900(92)90014-R

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

Summary—Quantitative ion microscopy of freeze‐fractured, freeze‐dried cultured cells is a technique for single cell and subcellular elemental analysis [1–3]. This review describes the technique and its usefulness in determining the uptake and subcellular distribution of the boron from boron neutron capture therap

ISSN:0248-4900    

DOI:10.1016/0248-4900(92)90015-S

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

Summary—Dynamic secondary ion mass spectrometry (SIMS) has been utilised to study the post‐mortem distribution of aluminium in air‐dried frozen sections from unfixed, unstained human brain in order to minimise contamination of the tissue and avoid redistribution and extraction of endogenous tissue aluminium. Substrates, sputter‐coated with silver, were found to be free of focal aluminium surface contamination and thus minimised substrate induced artefacts in the tissue aluminium ion image. SIMS imaging of aluminium secondary ions at a mass resolution that eliminated the major molecular interferences, combined with a photomontage technique provided a unique strategy for studying aluminium distribution in tissue unrivalled by other spatially resolved microanalytical techniques such as laser microprobe mass spectrometry or X‐ray microanalysis. Using this strategy, high densities of focal aluminium accumulations have been demonstrated in the cerebral cortex of the majority of chronic renal dialysis patients studied. In contrast, such aluminium accumulations were absent in control patients. SIMS imaging of aluminium appeared to provide much better discrimination between the dialysis patient group and the control group than one of the most widely used techniques for measuring aluminium in bulk samples, graphite furnace atomic absorption spectrometry. Preliminary studies have shown the feasibility of quantifying focal aluminium SIMS images obtained from brain tissue using aluminium‐loaded brain homogenates as referenc

ISSN:0248-4900    

DOI:10.1016/0248-4900(92)90016-T

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

Summary—Flotation on hot water (about 60°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 distr

ISSN:0248-4900    

DOI:10.1016/0248-4900(92)90017-U

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

Summary—Current controversies in root physiology relating to the uptake and translocation of mineral nutrients are presented. The opportunities for a SIMS contribution to resolve these controversies are discussed for each of the stable isotope tracers relevant to plant nutrition. It is concluded that for all major nutrients except phosphorus there are promising stable isotope tracers. At the same time, there are challenges to overcome in each case, with respect to background levels, peak interferences and sometimes sensitivity. Techniques of tissue preparation and handling are discussed in some detail, giving attention to the special requirements of plant tissue preparation and analysis for diffusable ions. It is suggested that adapting a preparation and transfer system, designed for production of bulk frozen‐hydrated cryofractured specimens, to a secondary ion mass spectrometer would permit easy, rapid preparation. Additionally, this preparation minimizes several serious technical problems inherent to other preparative methods. Difficulties in quantitation are treated briefly, outlining some difficulties specific to plant tissue analysis. Prospects for future applications in plant mineral nutrition are evaluated, taking into account current instrumental developme

ISSN:0248-4900    

DOI:10.1016/0248-4900(92)90018-V

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

Summary—Depth profiles of C, Na, Mg, Al, K and Ca were performed in the cuticle and wall of epidermal cells of flax hypocotyls, with current densities ranging from 0.2 to 1 pA μm−2. The crater bottoms were never flat, but exhibited fairly complex, filiform or alveolar structures. The profiles of K, Ca and Mg were reasonably parallel to one another. The Ca/Mg signal ratio was in the magnitude of 3.5 in the cuticle. The Na profile, except perhaps in the cuticle, did not parallel the K, Ca and Mg profiles, but rather paralleled the C profile. At the outset of the depth profiles,iein the cuticle, the intensity of the Na signal, although fairly variable, was usually above that of K; then there was an abrupt decrease of the Na signal, possibly at the border of the cuticle and of the wall. The Al signal usually began to increase, thus revealing the occurrence of perforations through the epidermis sample, after 80 min sputtering at a current density of 1 pA μm−2; the mean sputtering rate was thus estimated to be in the order of 1

ISSN:0248-4900    

DOI:10.1016/0248-4900(92)90019-W

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

Summary—The distribution of15N and14N compounds in cryofixed and resin embedded sections of soybean (Glycine maxL) leaves was studied by SIMS microscopy. The results indicate that, with a mass resolutionM/ΔMhigher than 6000, images of the nitrogen distribution can be obtained from the mapping of the two secondary cluster ions12C14N−and12C15N−, in samples of both control and15N‐labeled leaves. The ionic images were clearly related to the histological structure of the organ, and allow the detection of14N and15N at the subcellular level. Furthermore, relative measurements of the12C14N−and12C15N−beams made possible the quantification of the15N atom% in the various tissues

ISSN:0248-4900    

DOI:10.1016/0248-4900(92)90020-2

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

Summary—The virtues and limitations of SIMS ion microscopy are compared with other spectroscopic techniques applicable to biological microanalysis, with a special emphasis on techniques for elemental localization in biological tissue (electron, X‐ray, laser, nuclear, ion microprobes). Principal advantages of SIMS include high detection sensitivity, high depth resolution, isotope specificity, and possibilities for three‐dimensional imaging. Current limitations, especially in comparison to X‐ray microanalysis, center on lateral spatial resolution and quantification. Recent SIMS instrumentation advances involving field emission liquid metal ion sources and laser post‐ionization will help to minimize these limitations in the future. The molecular surface analysis capabilities of static SIMS, especially with the new developments in commercial time‐of‐flight spectrometers, are promising for application to biomimetic, biomaterials, and biological tissue or cell surfaces. However, the direct microchemical imaging of biomolecules in tissue samples using SIMS will be hindered by limited concentrations, small analytical volumes, and the inefficiencies of converting surface molecules to structurally significant gas phase ions. Indirect detection using elemental or isotopically tagged molecules, however, shows considerable promise for molecular imaging studies using SIMS i

ISSN:0248-4900    

DOI:10.1016/0248-4900(92)90021-R

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY