ISSN:0248-4900    

DOI:10.1016/0248-4900(92)90002-I

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

ISSN:0248-4900    

DOI:10.1016/0248-4900(92)90003-J

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

Summary—We attempted to indicate the requirements for biomedical applications of SIMS microscopy. Sample preparation methodology should preserve both the structural and the chemical integrity of the tissue. Furthermore, it is often necessary to correlate ionic and light microscope images. This implies a common methodological approach to sample preparation for both microscopes. The use of low or high mass resolution depends on the elements studied and their concentrations. To improve the acquisition and processing of images, digital imaging systems have to be designed and require both ionic and optical image superimposition. However, the images do not accurately reflect element concentration; a relative quantitative approach is possible by measuring secondary ion beam intensity. Using an internal reference element (carbon) and standard curves the results are expressed in μg/mg of tissue. Despite their limited lateral resolution (0.5 μm) the actual SIMS microscopes are very suitable for the resolution of biomedical problems posed by action modes and drug localization in human pathology. SIMS microscopy should provide a new tool for metabolic radiotherapy. by facilitating dose evaluation. The advent of high lateral resolution SIMS imaging (<0.1 μm) should open up new fields in biomedical investiga

ISSN:0248-4900    

DOI:10.1016/0248-4900(92)90004-K

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

Summary—The notion of diffusible ions is reviewed in the light of recent knowledge on the stage of water in biological matrices. It appears that ion distributions would be little affected as long as water‐macromolecular equilibrium is maintained, but they risk to be significantly modified during dehydration, because the transformation of bound water into highly solvating free water can produce ion displacements. In addition, differently hydrated areas may undergo unequal volume variations. The principal modes of preparing material for SIMS (secondary ion mass spectrometry) microscopy are envisaged from this viewpo

ISSN:0248-4900    

DOI:10.1016/0248-4900(92)90005-L

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

Summary—Sample preparation is a critical step in the elemental analysis of animal tissues and cell cultures with ion microscopy. Since live cells cannot be analyzed with ion microscopy, a careful sample fixation is necessary which preserves the native structural and chemical integrity of a specimen. The evaluation of morphological and chemical integrity of a fixed specimen is necessary before any physiological explanation of ion fluxes is interpreted based on ion microscopy. For diffusible ion localization studies, strict cryogenic procedures are recommended. Examples are shown for diffusible ion microanalysis in frozen‐freeze‐dried tissues and cell cultures. Ion microscopy studies of tightly bound elements/molecules may be conducted in chemically fixed and/or plastic embedded specimens. Since it is not generally known which elements/molecules are tightly bound to the tissue matrix, a confirmation of elemental distribution with cryogenic procedures is desirable. A recent approach of combining laser scanning confocal fluorescence microscopy and ion microscopy on the same frozen freeze‐dried cell is also discussed for recognizing smaller cytoplasmic structures in ion microscopy

ISSN:0248-4900    

DOI:10.1016/0248-4900(92)90006-M

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

Summary—The secondary ion microscope described here allows to obtain the simultaneous registration of chemical and isotopic distribution maps of several elements composing the sample. The instrument has been specially designed to optimize both sensitivity and selectivity: bombardment with primary Cs+ions to increase the ionization yields of negative secondary ions, efficient collection of secondary ions at the target surface, matching of the secondary ion beam etendue with the acceptance of the mass spectrometer working at high mass resolution, spectrometer with parallel detection capabilities. The probe diameter can be made as low as 30 nm and ion induced electron images registered at the same time as ion images. Presently, four ion micrographs are obtained simultaneously over a field of view up to 20 × 20 μm2containing up to 512 × 512 pixels. Examples are shown with an ion probe diameter of 0.

ISSN:0248-4900    

DOI:10.1016/0248-4900(92)90007-N

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

Summary—Analytical imaging by secondary ion mass spectrometry (SIMS) using a state‐of‐the‐art scanning ion microprobe enables the detection and mapping of tracer isotopes in human metaphase chromosomes. The stimulated mitosis of cells cultured in media containing labelled nucleosides, typically14C‐labelled thymidine or adenosine, and BrDU, yields chromosomes that have incorporated the labelled molecule in their constituent DNA. The label is subsequently detected and localized by SIMS imaging. The relative label signal intensities of sister chromatids can be quantified. The occurrence of sister chromatid exchanges (SCE) can be detected. The distribution of specific nucleosides can be directly mapped. This is non‐uniform along the chromatids, giving rise to characteristic banding patterns (SIMS bands) that seem to correspond to the well known G‐ or Q‐bands resulting from conventional staining methods. The study of a number of cytogenetic problems is expected to benefit from the use of this new method of approach, similar in principle, but potentially more sensitive and capable of higher spatial resolution than

ISSN:0248-4900    

DOI:10.1016/0248-4900(92)90008-O

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

Summary—Ecotoxicological investigations were performed on two sets of biological models. The first one concerns marine pollution and was composed of invertebrates (molluscs and crustaceans) contaminated by stable or radioactive elements originating from wastes discharged into sea water. The second one concerns freshwater pollution and was composed of vertebrates (fish) contaminated by aluminium which was dissolved in rivers, as a consequence of an atmospheric pollution by acid rain. Mechanisms involved in the uptake, storage and elimination processes of these toxicants were studied, with a special emphasis on cellular and subcellular aspects of concentration sites. Two microanalytical methods were employed: secondary ion mass spectrometry (SIMS), using the ion microscope and the ion microprobe, and X‐ray spectrometry using the electron microprobe (EMP). SIMS, which enables the visualization of trace elements, was associated with an image processing system using a highly sensitive television camera connected to an image computer. Polychromatic images were obtained, allowing to establish the cellular distribution of metal contaminants. In marine organisms, the target organs and tissues of Al, rare earth elements (Tm and La) and radionuclides (U, Pu, Am) were shown to be mainly digestive gland and exoskeleton. The target organelles were shown to be spherocrystals and lysosomes where the enzymatic lysosomal coprecipitation with phosphorus was observed. Amoebocytes, which are enzymatically equipped with lysosomal phosphatase, were involved in the phagocytic clearance of metal pollutants. In trout, two processes appeared to be involved in Al accumulation. The first one corresponds to the well known insolubilisation of Al phosphate, within lysosomes of organs devoted to uptake and excretion such as gill and kidney. The second one demonstrates that organs and tissues which cannot eliminate, such as bone, heart and brain, retain Al, exhibiting a high intracellular metal concentration; moreover, large Al deposits inducing nervous tissue destruction have been observed. Data have been discussed in connection with the relationship between man and his environm

ISSN:0248-4900    

DOI:10.1016/0248-4900(92)90009-P

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

Summary—We defined the SIMS conditions for radioiodine detection in animal and man thyroid follicles, in tissue sections (3 μm) chemically fixed and resin embedded. Two radioisotopes were tested:125I and129I, of high (14 mCi125I μg−1) and low specific activity (1.07 10−6mCi129I μg−1). In animal study, Wistar rats fed a normal iodine diet (10 μg127I day−1) were injected ip 24 h before sacrifice either with125I (7 10−3μg) or with129I at a dose identical to iodine diet (10 μg) or 3 times higher (30 μg). No SIMS signal of125I was obtainedin vivodue to its too low concentration, while radioiodine distribution was evidenced with both doses of129I. Local concentration of previously stored127I in follicular lumen was not modified, when compared to control (4.14 ± 0.03 μg/mg, m ± SE), by125I or129I at a dose of 10 μg, but was nearly doubled with129I at a dose of 30 μg, proof of a pharmacological effect on thyroid iodine regulation. In human study129I was excluded due to its long half‐life (1.6 107years), and125I was tested onlyin vitroon two surgical specimens of normal perinodular thyroid tissue maintained in mini‐organ culture for 48 h in presence of 100 μCi/ml of125I. The125I was detectable, its concentration was 1000‐fold higher than that of127I (1.5 ± 0.004 μg/mg). For bothin vivoandin vitrostudies, a positive correlation exists between newly organified radioiodine (125I or129I) and previously stored iodine (127I). In conclusion, the radioisotope129I used at a dose of 10 μg is well adapted for SIMS detectionin vivoof thyroid exchangeable iodine, but only in animal, while125I isotope is especiall

ISSN:0248-4900    

DOI:10.1016/0248-4900(92)90010-X

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

Summary—We took advantage of one of the main possibilities of ion microscopy,ieisotopic analysis, to study the cellular distribution of molecules labelled either with carbon 14 or with stable isotopes of low natural abundance such as nitrogen 15 and deuterium. The surface of the sample is bombarded with an ion beam (O2+, Cs+etc). Secondary ions emitted from the sample are filtered by a mass spectrometer and the distribution of the labelling isotope is recorded. In this way, we obtained images showing the characteristic distribution of14C‐thymidine andd‐arginine in human fibroblasts, and of15N‐adenine in organotypic cultures of human breast cancer cells. The spatial resolution on the acquired images was close to 0.1 μm when using the UPS‐ONERA ion microprobe. The sensitivity of the method for detecting carbon 14 is far greater than that of autoradiography and the technique is both fast and quantitative. On the other hand, the capacity of ion microscopy for studying the tissular distribution of molecules labelled with stable isotopes, opens the way for biological and pharmacological tracer studies of huma

ISSN:0248-4900    

DOI:10.1016/0248-4900(92)90011-O

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY