Computerized 3-dimensional analysis of mitochondrial structure

Three-dimensional reconstruction of cells from serial sections and whole-cell mounts using multilevel contouring of stereo micrographs

A comprehensive computer-graphics-based system (STERECON) is described for tracing and digitizing contours from individual or stereopair electron micrographs. The contours are drawn in parallel planes within the micrographs. Provision is also made for tracing and digitizing in full three-dimensional (3-D) coordinates in any direction along linear structures such as cytoskeletal elements. The stereopair micrographs are viewed in combination with the contours being traced on a graphics terminal monitor. This is done either by projecting original electron micrograph (EM) negatives onto a screen and optically combining these images with contour lines being drawn on the monitor, or by first digitizing the images and displaying them directly on the monitor along with the contour lines. Prior image digitization allows computer enhancement of the structures to be contoured. Correction and alignment routines are included to deal with variable section thickness, section distortion and mass loss, variations in photography in the electron microscope, and terminal screen curvature when combining projected images with contour lines on the monitor. The STERECON system organizes and displays the digitized data from successive sections as a 3-D reconstruction. Reconstructions can be viewed in any orientation as contour stacks with hidden lines removed; as wire-frame models; or as shaded, solid models with variable lighting, transparency, and reflectivity. Volumes and surface areas of the reconstructed objects can be determined. Particular attention was paid to making the system convenient for the biological user. Users are given a choice of three different stereo-viewing methods.

Development of stereological analysis software for the calculation of volume, number and surface density

COSAS, an acronym for COmputerized Stereological Analysis System, is software designed to facilitate the process of quantitative morphological analysis. It is a flexible, reliable, and easy to use software system which provides the biologist with a simple means for performing stereological analysis. It provides for estimation of volume and surface density and allows for direct calculation of diameter information from planimetric data. The latter capability is unique to COSAS and provides the ability to calculate longest and shortest diameters for convex profiles, enabling calculation of number density. Access to all intermediate calculations is possible, so the process of transformation of raw data into the stereological descriptors can be completely exposed. This serves two purposes: (1) it provides a means for tracing results; (2) the intermediate values can be utilized independently. This system was used to analyze peroxisomes in tissues from patients with Zellweger's disease and neonatal-onset adrenoleukodystrophy. The system was also used to facilitate an immunocytochemical analysis of cytochrome P450 topology in the endoplasmic reticulum membrane.

Shape changes and polarization of cells migrating through tissue. A high-voltage electron microscope and computer graphics study of serial thick sections

Structural changes of carcinoma cells and fibroblasts migrating through small spaces in the elastic-collagen reticulum of mouse peritoneum have been studied by high-voltage electron microscopy of serial thick sections and by computer graphics reconstruction of cell profiles. The change of shape profile of an individual cell, between serial sections is large and the distribution of organelles is very non-uniform and changes markedly between sections. Conclusions about adhesion, intercell contact, cell shape and polarization of cytoplasmic organelles could only be reached by assessing a complete set of serial sections. Our preliminary results suggest that interesting structural changes occur in both carcinoma cells and fibroblasts when migrating through this tissue.