High-speed electron microscope autoradiographic studies of diffusible compounds
Three important factors are necessary for successful electron microscope autoradiography (EM-ARG): good resolution, proper preparation of the radioactive isotope (RI) labeled diffusible compounds, and shortened exposure time for ARG. The resolution problem is fundamental to EM-ARG. However, unless the diffusible RI compounds have been fixed correctly in the tissues during preparation, good resolution is useless. It is also necessary to shorten the exposure time for ARG. As yet, a high-speed ARG method for electron microscopy has not been reported, although scintillation ARG methods have been applied to macro- and micro-ARG since 1960. High specific activity, a large amount of radioactivity per unit exposure for radio incorporation (incubation), and careful selection of labeled compounds that concentrate in the DNA or RNA of cell organelles may increase the sensitivity of the emulsion and shorten the exposure time for ARG. For example, labeled thymidine accumulates in nuclear DNA, /sup 3/H-SPG (Schizophyllan-produced polyglucan) is incorporated into lysosomal granules, and labeled iodine concentrates in thyroid follicles, often increasing the sensitivity of the emulsion and shortening the exposure time, but high-resolution ARG continues to be necessary, even though it requires 4 weeks or more of exposure time. Scintillation autoradiography using tritium seems unstable. We propose a new way to shorten exposure time for EM-ARG, by combining overdevelopment with coating both sides of the grid with emulsion. This method is approximately 100 times more sensitive than the conventional method, and only 4 days of exposure time are required, in contrast to the 1 month usually needed.
- Research Organization:
- Department of Cell Biology, Medical Research Institute, Tokyo Medical and Dental University, Japan
- OSTI ID:
- 5673848
- Journal Information:
- J. Histochem. Cytochem.; (United States), Journal Name: J. Histochem. Cytochem.; (United States) Vol. 29:1A; ISSN JHCYA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
59 BASIC BIOLOGICAL SCIENCES
AMINO ACIDS
AUTORADIOGRAPHY
AZINES
BODY
CARBOXYLIC ACIDS
CELL CONSTITUENTS
DNA
ELECTRON MICROSCOPY
ENDOCRINE GLANDS
GLANDS
HETEROCYCLIC COMPOUNDS
IODINE ISOTOPES
ISOTOPES
LABELLED COMPOUNDS
LYSOSOMES
MICROSCOPY
NUCLEAR EMULSIONS
NUCLEIC ACIDS
NUCLEOSIDES
NUCLEOTIDES
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANOIDS
ORGANS
PYRIMIDINES
RESOLUTION
RIBOSIDES
RNA
SPATIAL RESOLUTION
THYMIDINE
THYROID
TRITIUM COMPOUNDS