This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Mellors, R. C. Search for Related Content PubMed PubMed Citation Articles by Mellors, R. C.

Microscopy. I: A Review

( Division of Experimental Pathology, Sloan-Kettering Institute for Cancer Research, and Pathology Laboratories, Memorial Center, New York, N.Y.)

A description has been given of some of the recent advances in methods of microscopy of the cell which utilize the phase (phase, interference, and polarizing microscopy), the plane (polarizing microscopy), the dispersion (dispersion microscopy), and the amplitude and the frequency (microspectroscopy) of light waves in the optical spectrum. The applications of these methods to the study of the mass, the elementary and organic chemical composition, and the structure of the nucleus, nucleolus, chromosomes, mitotic apparatus, and cytoplasmic particles are presented with a view toward the manifest or potential significance of the results in cancer research.

The unique value of the phase microscope is that it, as no other method, provides a means for the structural analysis of living cells without the hazard of injury or the uncertainty of artifact. Outstanding among the applications are the study of the events during mitosis, the formation and the movement of chromosomes, and the structural alterations in the mitochondria.

Recent improvements in the polarizing microscope make it possible to investigate the spindle apparatus in the living, dividing cell and provide information which indicates the spindle to be an orienting force through which a co-ordinated contractile mechanism for chromosome movement is built up from protoplasm. It has been shown by a study of the effects of colchicine that there is a close relation between the mechanical integrity of the spindle and the maintenance of the metaphase plate of chromosomes. The contractility of spindle fibers is interpreted in terms of the folding of molecular (polypeptide) chains during anaphase.

By means of interference microscopy, loci of identical optical paths through a cell-object appear as alternate bright and dark lines, called interference fringes, which form a contour-like map of the object. This effect may be interpreted in terms of variations in thickness of the cell-object, with a resolution of the order of 0.03 µ, or it may be used to compute the anhydrous organic (protein) mass and the hydrous protoplasmic mass of a living, or unfixed, cell-object.

Dispersion microscopy provides a method for the determination of the refractive index of a biological object. The difference in index between certain cellular structures is such that, by the use of this method, structures appear in contrasting color due to optical effects.

The observations that nucleic acids are prominent constituents of biological elements such as chromosomes, nucleoli, mitochondria, and, presumably, the genes focus great interest upon the role of these compounds and their chemical moieties in the mechanisms of growth and the genesis of cancer. Applications of ultraviolet and visible microspectroscopy in these fields of interest are discussed. The quantitative estimation of nucleic acids in individual nuclei of cancer cells of the mouse and the human cervix uteri yields values that are distinctly greater, by a geometrical progression, than those of the normal cell.

The use of infrared microspectroscopy in the analysis of the biochemical constituents of tissues and the tissues themselves is discussed in terms of the identification of organic compounds and the investigation of molecular structure.

Fluorescence microscopy and microspectroscopy provide a means for the investigation of the localization and the distribution of fluorescent carcinogens in tissues and cells. Fluorescent dyestuffs (fluorochromes) may be used to differentiate nuclear and cytoplasmic structures, as do conventional dyestuffs. Exfoliating cancer cells of the vaginal smear have distinguishing properties relative to normal cells when stained with fluorochromes. One or more of these discriminative properties may be utilized by an automatic scanning device for the detection of cancer cells.

^* This work was done under a Damon Runyon Senior Clinical Research Fellowship of the American Cancer Society, Inc., and was supported in part by a research grant from the National Cancer Institute of the National Institutes of Health, Public Health Service.

Received 9/ 6/52.