Microchemical imaging in biomedical research

1992 ◽  
Vol 50 (2) ◽  
pp. 1118-1119
Author(s):  
P. Ingram
Keyword(s):  
Data Analysis ◽  
Electron Probe ◽  
The Other ◽  
X Ray ◽  
Cell Element ◽  
Physiological Information ◽  
Functional States ◽  
Elemental Maps ◽  
Electron Energy Loss ◽  
Secondary Ion

It is well established that unique physiological information can be obtained by rapidly freezing cells in various functional states and analyzing the cell element content and distribution by electron probe x-ray microanalysis. (The other techniques of microanalysis that are amenable to imaging, such as electron energy loss spectroscopy, secondary ion mass spectroscopy, particle induced x-ray emission etc., are not addressed in this tutorial.) However, the usual processes of data acquisition are labor intensive and lengthy, requiring that x-ray counts be collected from individually selected regions of each cell in question and that data analysis be performed subsequent to data collection. A judicious combination of quantitative elemental maps and static raster probes adds not only an additional overall perception of what is occurring during a particular biological manipulation or event, but substantially increases data productivity. Recent advances in microcomputer instrumentation and software have made readily feasible the acquisition and processing of digital quantitative x-ray maps of one to several cells.

Where Art Thou, Calcium?

1997 ◽  
Vol 3 (S2) ◽  
pp. 913-914
Author(s):  
A.P. Somlyo
Keyword(s):  
Spatial Resolution ◽  
Electron Probe ◽  
High Sensitivity ◽  
Detection Sensitivity ◽  
Optical Methods ◽  
X Ray ◽  
Electron Energy Loss ◽  
The Relationship ◽  
Intracellular Messenger ◽  
Cellular Organelles

Ever since the recognition of calcium as a major intracellular messenger of signal transduction, its subcellular localization and intracellular movements have been intensively sought through electron and light optical methods. Electron probe microanalysis (EPMA), X-ray mapping, electron energy-loss spectroscopy (EELS) and energy-filtered imaging still provide the highest spatial resolution for measuring total calcium, whereas with light optical methods (fluorescent, luminescent and absorbance dyes) free [Ca2+]i can be measured with high sensitivity and time resolution. This presentation will summarize the relationship, whether collision or convergence, between the results of electron and light optical methods, with particular reference to mitochondrial Ca, and consider the potential for further improvements in detection sensitivity and spatial resolution.Sarcoplasmic and endoplasmic reticulum: Early attempts to quantitate Ca in cellular organelles with EPMA were directed at the sarcoplasmic reticulum (SR) of skeletal muscle, where EPMA could also address questions not amenable to studies of isolated SR.

Combined Plasma-Microincineration, Electron Microscopy And Electron Probe Microanalysis For Fine Localization of Biological Mineral Substances

1973 ◽  
Vol 31 ◽  
pp. 334-335 ◽  
Author(s):  
Richard S. Thomas ◽  
Mabel I. Corlett
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Electron Probe ◽  
Oxygen Plasma ◽  
Chemical Nature ◽  
The Other ◽  
X Ray ◽  
Transmission Electron ◽  
Mineral Substances ◽  
Fine Localization

Ash patterns produced by oxygen plasma microincineration(OPM) of thin-sectioned biological materials and examined with the transmission electron microscope (TEM) can show unambiguously the distribution of mineral substances in the specimen with resolutions down to 100 Å. The chemical nature of the mineral is not demonstrated, however. Electron-probe X-ray microanalysis (EXM), on the other hand, can determine precisely the nature of the mineral in ashgd or unashed sections but its spatial resolution is limited to 1000-10,000 A at best. Also its sensitivity of analysis on unashed specimens is limited by intolerance of the specimen to high beam intensities. Using both TEM and EXM together on ash patterns of suitable specimens can overcome their independent spatial and chemical limitations. Furthermore, use of OPM produces a highly stable mineral specimen for EXM, thereby improving sensitivity.

Correction for Non-Linearity of Proportional Counter Systems in Electron Probe X-Ray Microanalysis

1965 ◽  
Vol 9 ◽  
pp. 208-220 ◽  
Author(s):  
Kurt F. J. Heinrich ◽  
Donald Vieth ◽  
Harvey Yakowitz
Keyword(s):  
Theoretical Basis ◽  
Electron Probe ◽  
Dead Time ◽  
Pulse Height ◽  
The Other ◽  
Time Effects ◽  
X Ray ◽  
Electron Probe Microanalyzer ◽  
Intensity Measurements

AbstractWhile the theoretical basis for the correction of non-linearity of detector systems is well known, methods for the determination of dead-time effects must be adapted to electron probe microanalyzer systems. Two such methods, one employing both X-ray and current measurements and the other employing simultaneous X-ray measurements on two spectrometers, are described. The effect of pulse-height shrinkage at high counting rates on the linearity of the detector system is discussed. When the proposed corrections for the dead-time of X-ray detector systems employing proportional counters are applied to the X-ray intensity measurements obtained with the electron probe microanalyzer, count rates as high as 50,000 counts/sec can be used.

Bio-PIXE AT THE TAKIZAWA FACILITY (Bio-PIXE WITH A BABY CYCLOTRON)

1992 ◽  
Vol 02 (03) ◽  
pp. 325-330 ◽  
Author(s):  
K. SERA ◽  
T. YANAGISAWA ◽  
H. TSUNODA ◽  
S. FUTATSUGAWA ◽  
S. HATAKEYAMA ◽  
...  
Keyword(s):  
Data Analysis ◽  
Computer Program ◽  
Simultaneous Determination ◽  
Spectrum Analysis ◽  
The Other ◽  
Personal Computers ◽  
Measuring System ◽  
X Ray ◽  
Spectral Fitting

For the developement of bio-PIXE, two problems remain to be solved; one in accelerator availability and the other in data analysis. To improve the former, a method of applying baby cyclotrons to PIXE has been developed. To solve the latter, the computer program SAPIX for x-ray spectrum analysis ,which runs on ordinary personal computers and is fairly easy to operate has been developed. Examples of spectral fitting by the SAPIX and a description of the program are given. Further, the two-detector measuring system which we have employed for the simultaneous determination of all elements is reported.

Electron probe analysis, x-ray mapping and electron energy loss spectroscopy of elemental distribution in Escherichia coli B

1984 ◽  
Vol 42 ◽  
pp. 570-571
Author(s):  
Chung-Fu Chang ◽  
Henry Shuman ◽  
Andrew P. Somlyo
Keyword(s):  
Energy Loss ◽  
Electron Energy ◽  
Electron Energy Loss Spectroscopy ◽  
Electron Probe ◽  
Bright Field Image ◽  
X Ray ◽  
E Coli ◽  
Specimen Holder ◽  
Freeze Dried ◽  
Electron Energy Loss

The ability of bacteria to concentrate minerals is well known, but little is known about the subcellular distribution of ions. Electron probe microanalysis, X-ray mapping and electron energy loss spectroscopy of ultrathin cryosections are particularly suitable for determining composition at the ultrastructural level in cells, including bacterial spores. In the present study, we report preliminary experiments with these methods on elemental concentrations and distribution in E. coli B, including differences in the calcium content between dividing and non-dividing cells.E. coli B were grown in the presence of 1% tryptone (DIFCO), 0.2% glucose and 0.1M NaCl. The cells were harvested at a concentration of ∽3x108 cell/ml (in the late log phase). Cells were washed in nominallv ion-free solutions and then frozen, in the presence of 10% PVP, in supercooled Freon 22 at -164°C. The specimens were freeze-dried and cryosectloned as described previously. Analyses were performed on a Gatan LN2 cold specimen holder, at a temperature of -101°C. A bright-field image of the cryosectioned E. coli is shown in Fig. 1.

Element analysis with the imaging electron energy loss spectrometer of the zeiss EM 902

1986 ◽  
Vol 44 ◽  
pp. 600-601
Author(s):  
J. Bihr ◽  
A. Rilk ◽  
W.I. Miller
Keyword(s):  
Energy Loss ◽  
Electron Energy ◽  
Electron Spectroscopic Imaging ◽  
Element Analysis ◽  
X Ray ◽  
Electron Energy Loss Spectrometer ◽  
Elemental Maps ◽  
Electron Energy Loss ◽  
Electron Energy Loss Spectra ◽  
Loss Range

An imaging electron energy loss spectrometer can be used to produce elemental maps with highest spatial resolution by Electron Spectroscopic Imaging (ESI). Simultaneously, electron energy loss spectra (EELS) can also be recorded. It is therefore simple to combine morphological examinations with the analytical method of electron energy loss spetroscopy (Figs. 2, 3)The electron energy loss spectrometer of the EM 902, used in combination with a suitable electron detector (Fig. 1), provides the possibility of recording electron energy loss spectra over an energy loss range from 0 to 2000 eV. In this way, all elements of the periodic system can be detected via their K, L, M, N or O absorption edges (Fig. 5). Unlike X-ray microanalysis, this technique is especially suitable for detecting light and medium-heavy elements which are of special significance in biological and medical research.

Sign in / Sign up

Export Citation Format

Share Document