CHARACTERISTIC FEATURES OF CHANGES IN THE FIELD OF VISION IN PATIENTS WITH BRAIN TUMORS

One of the most characteristic features of cancer cells is their ability to metastasia. It is suggested that the modifications of the structure and properties of cancer cells surfaces play the main role in this process. The present work was aimed at finding out what ultrastructural features apear in tumor in vivo which removal of individual cancer cells from the cell population can provide. For this purpose the cellular interactions in the normal human thyroid and cancer tumor of this gland electron microscopic were studied. The tissues were fixed in osmium tetroxide and were embedded in Araldite-Epon.In normal human thyroid the most common type of intercellular contacts was represented by simple junction formed by the parallelalignment of adjacent cell membranees leaving in between an intermembranes space 15-20 nm filled with electronlucid material (Fig. 1a). Sometimes in the basal part of cells dilatations of the intercellular space 40-50 nm wide were found (Fig. 1a). Here the cell surfaces may form single short microvilli.

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Development of 200kV ultrahigh-resolution analytical electron microscope

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100152513 ◽

1989 ◽

Vol 47 ◽

pp. 108-109

Author(s):

T. Kaneyama ◽

M. Naruse ◽

Y. Ishida ◽

M. Kersker

Keyword(s):

Electron Microscope ◽

Optical Constants ◽

Materials Science ◽

Objective Lens ◽

The Finite Element Method ◽

Ultrahigh Resolution ◽

Analytical Electron ◽

Analytical Electron Microscope ◽

Characteristic Features ◽

Better Than

In the field of materials science, the importance of the ultrahigh resolution analytical electron microscope (UHRAEM) is increasing. A new UHRAEM which provides a resolution of better than 0.2 nm and allows analysis of a few nm areas has been developed. [Fig. 1 shows the external view] The followings are some characteristic features of the UHRAEM.Objective lens (OL)Two types of OL polepieces (URP for ±10' specimen tilt and ARP for ±30' tilt) have been developed. The optical constants shown in the table on the next page are figures calculated by the finite element method. However, Cs was experimentally confirmed by two methods (namely, Beam Tilt method and Krivanek method) as 0.45 ∼ 0.50 mm for URP and as 0.9 ∼ 1.0 mm for ARP, respectively. Fig. 2 shows an optical diffractogram obtained from a micrograph of amorphous carbon with URP under the Scherzer defocus condition. It demonstrates a resolution of 0.19 nm and a Cs smaller than 0.5 mm.

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