Ultramicrotome


Also found in: Dictionary, Thesaurus, Medical, Wikipedia.

ultramicrotome

[¦əl·trə′mī·krə‚tōm]
(engineering)
A microtome which uses a glass or diamond knife, allowing sections of cells to be cut 300 nanometers in thickness.

Ultramicrotome

 

an instrument for cutting extremely thin sections of tissue for examination under an electron microscope.

The motion of the knife or the tissue is strictly regulated at a specific height in order to obtain sections that are usually not thicker than 200 angstroms (A) and are sometimes about 50 A thick. The thickness of a section depends on the quality of the fixing medium and the sharpness of the cutting edge of the knife. In most ultramicrotomes, the knife does not move, and the tissue is moved mechanically or, most often, thermally. The thermal mechanism, which was proposed in 1953 by F. Sjôstrand, operates on the basis of the controlled thermal expansion of the support rod to which the tissue is attached.

The USSR has developed an ultramicrotome based on the thermal mechanism that furnishes sections with a thickness of 50-800 A. Glass and diamond blades are used in ultramicrotomes. The quality of the blades is checked under a dark-field microscope, where the cutting edge of a blade of sufficient quality appears as a bright straight line.

REFERENCES

Elektronnomikroskopicheskie metody issledovaniia biologicheskikh ob”ektov. Moscow, 1963.
Weakley, B. S. Elektronnaia mikroskopiia dlia nachinaiushchikh. Moscow, 1975.
Sjôstrand, F. S. Electron Microscopy of Cells and Tissues, vol. 1. New York-London, 1967.

S. IA. ZALKIND

Mentioned in ?
References in periodicals archive ?
The semithin plastic sections (1 im) of gBMSC-seeded silk fiber were cut using an ultramicrotome with glass knives, stained with 1% Toluidine Blue, viewed under the light microscope (Nikon) and photographed.
6 pm ultrathin sections were cut using a glass knife on an LKB V Ultramicrotome (LKB Company, Bromma, Sweden).
To prepare the polymer samples, slices of 5 lm thickness were first cut by ultramicrotome (Ultrotome 2128 by LKB), melted between two microscopy cover glasses, and pressed gently to reduce thickness.
These samples were postfixed with 1% osmium tetraoxide, dehydrated with alcohol, included in plastic resin (EPON), cut with an ultramicrotome and contrasted with uranyl acetate and lead citrate.
Ultrathin sections were cut with a Supernova ultramicrotome (Reickert Jung, Vienna, Austria), mounted on copper grids, stained with uranyl acetate and lead citrate and then observed and photographed with a Philips CM10 transmission electron microscope (TEM; Philips Scientifics, Eindhoven, The Netherlands).
One section with 60 nm-thickness was cut from each epon block using a ultramicrotome.
Thin sections (50-70 nm) were cut by a Leica UCT-125 ultramicrotome (Leica Microsystems GmbH, Vienna-Austria) and contrasted with uranyl acetate and lead citrate.
Embryonic or juvenile feather filaments were sectioned at 1-3 [micro]m thickness in both cross, oblique and longitudinal planes using an ultramicrotome.
5 [micro]m using a histodiamond knife (Diatome, Electron Microscopy Sciences, Inc) on an ultramicrotome and stained them with toluidine blue.
Leica also introduced a number of specimen preparation products, including a high pressure freezer, automatic freeze substitution systems anda new ultramicrotome.
Several instruments were used to prepare samples including a Micrion 2500 Focused Ion Beam (FIB) instrument, a Leica Ultracut UCT ultramicrotome equipped with a diamond knife, and a Gatan Model 691 Precision Ion Polishing System (PIPS).
Finally, the samples were stored at 37[degrees]C for 48 hours, and 60 nm slices were taken with a LKB Novo ultramicrotome (Sweden).