Ultraviolet Absorption in Epidermoid Cancer Cells

Flow cytometry: past and future

Flow cytometry is a single-cell technology that measures scatter and fluorescence to establish a set of unique cellular properties. Flow cytometry is used in many areas of science, in particular biotechnology and medicine, but also in industrial applications. Flow cytometry can identify multiple phenotypic subsets from a mixture, select a single cell and even isolate that cell by a process called cell sorting. The field is currently undergoing dramatic changes. We are moving rapidly from the polychromic flow cytometry that has been the go-to technology for 45 years to spectral flow cytometry, which is now the most significant change in nearly half a century of flow cytometry. With change comes opportunity. Even spectral flow cytometry will morph into second-generation spectral flow cytometry within 5 years. New, exciting features will open up molecular diagnostics and physiology to flow cytometry.

Pathfinders in oncology from the time the causal relation between tobacco use and lung cancer was established to publication of the first Cancer Staging Manual by the American Joint Committee on Cancer

During the period from 1962 to 1977, several antigens, notably carcinoembryonic antigen and prostate-specific antigen, were discovered and entered clinical use. Ultrasonography, positron emission tomography scanning, and magnetic resonance imaging were introduced, and adjuvant radiation and chemotherapy after limited surgery became routine procedures. Radioimmunoassay and immunohistochemistry techniques were standardized. The announcement in England and the United States that tobacco is a potent lung carcinogen was long delayed, important news. The US Cancer Act of 1971 made it possible to experiment with newly discovered drugs, transfer promising therapeutic agents from the laboratory to the clinic, and finance randomized clinical trials. Oncologists achieved a series of successes with combination chemotherapy in childhood cancers, adult lymphomas, and testis tumors. Clinical trials demonstrated that breast-conserving therapy is as effective as mastectomy. The discovery of retroviruses, reverse transcriptase, and vascular endothelial growth factor was coupled with learning about oncogenes. The 2-hit theory and the reciprocal translocation of chromosomes helped to solve some of the riddles of oncogenesis. The staging classification of cancers by the American Joint Committee on Cancer unified clinical and pathologic handling and prognostication of malignant tumors. The progress made in oncology between 1962 and 1977 came about through the dedicated work of many individuals. However, there were 9 pathfinders (3 medical oncologists, 2 surgeons, 1 medical nuclear physicist, 1 pediatrician geneticist, 1 hematologist geneticist, and 1 virologist) who, despite their diverse backgrounds, personalities, and interest, made extraordinary contributions to oncology.

A note from history: Landmarks in history of cancer, Part 6

In the 3 decades from 1940 to 1970, the United States became the nucleus for research, diagnosis, and treatment of cancer. The discovery of anticancer drugs, and the clinical demonstration that chemotherapy and radiation can cure cancer and have the ability to prevent recurrence of cancer, were incontrovertibly the most remarkable groundbreaking events. Consequently, the trend of less surgery and more multimodality therapy began. The introduction of radioautography, mammography, ultrasonography, computed tomography, Papanicolaou smear, and other novel laboratory tests furthered early detection of cancer and refined accurate diagnosis. The unequivocal linking of lung cancer to cigarette smoking made medical history. The delineation of the potential role of oncogenes adduced new thoughts about oncogenesis and cancer prevention, and pathologists finalized the classification and nosology of tumors. Finally, it is worth noting that although more advances were made in the detection, diagnosis, and treatment of cancers than any other period in history, the overall mortality rate of patients with cancer remained high and unchanged.

Wallace H. Coulter: decades of invention and discovery

Only a few inventors can be said to have made as great an impact on mankind as Wallace Coulter. His inquisitive mind and ability to see well beyond what existed served him well for 40 years of inventing. So many of the fundamental tools that exist today in the area of hematology were derived from or driven by Coulter's inventions that he could be called the most technological innovator in the field of modern hematology. In achieving these discoveries Wallace Coulter was clearly capable of visualizing future opportunities that few others recognized. His vision was combined with an uncanny ability to translate his ideas into products. He developed a large number of tools that shaped the fields of cytometry, image analysis, and industrial materials. His understanding of the future power of computation drove him to link these technologies in a unique way. In the end, Coulter shaped the technologies that ultimately drove hematology in a new direction, one that remains on a critical pathway linking technology innovation all the way to true translational impact. It was said of Henry Ford that "[h]e has no notion that wealth has made him great, and any one who is imprest merely by his wealth bores him. In his personal contacts he likes to dodge the subject. He would prefer to talk with a machinist about machinery, or with somebody who likes birds about birds. In these contacts, he asks no deference; and if he gets it, he suspects it is mere deference to wealth, and that ends his interest."(1) The same could be said of Wallace Coulter, who, like Ford, understood the concepts of mass production and customer service. Coulter had the ability to recognize the opportunity and fulfill the need for development of a blood-cell counter that could be placed in every pathology laboratory, and in so doing transformed a field from a qualitative to a quantitative environment. Every person who has ever entered a medical lab, hospital, or doctor's office has felt the impact of Coulter's discovery.

Sex-sorting sperm using flow cytometry/cell sorting

The sex of mammalian offspring can be predetermined by flow sorting relatively pure living populations of X- and Y-chromosome-bearing sperm. This method is based on precise staining of the DNA of sperm with the nucleic acid-specific fluorophore, Hoechst 33342, to differentiate between the subpopulations of X- and Y-sperm. The fluorescently stained sperm are then sex-sorted using a specialized high speed sorter, MoFlo(®) SX XDP, and collected into biologically supportive media prior to reconcentration and cryopreservation in numbers adequate for use with artificial insemination for some species or for in vitro fertilization. Sperm sorting can provide subpopulations of X- or Y-bearing bovine sperm at rates in the 8,000 sperm/s range while maintaining; a purity of 90% such that it has been applied to cattle on a commercial basis. The sex of offspring has been predetermined in a wide variety of mammalian species including cattle, swine, horses, sheep, goats, dogs, cats, deer, elk, dolphins, water buffalo as well as in humans using flow cytometric sorting of X- and Y-sperm.

Flow cytometric measurements of DNA and other cell components in human tumors: a critical appraisal

Fundamental principles of flow cytometry with emphasis on DNA measurements and cell cycle analysis in human cells and tissues are summarized. Some of the pitfalls of cell preparation techniques and histogram interpretation are discussed at length. While consensus has been reached for some organs and tumors that DNA quantitation by flow cytometry (or image cytometry) may be of prognostic value, for most cancers studied to date the information remains incomplete. Thoroughly lacking are well-structured prospective studies because retrospective studies, while suggestive, may not necessarily be of the same value. Potential usefulness of other tumor markers is briefly discussed. Many fundamental questions concerning definitions of "diploid" and "aneuploid" tumors have not been satisfactorily settled. While the goal of "objective measurements" is worthy of further pursuit, the interpretation of results is often highly subjective. The biologic reasons for behavioral differences between diploid and aneuploid tumors are still totally obscure.

Spectrophotometer: new instrument for ultrarapid cell analysis

A new device has been developed for measuring and displaying multiple spectrophotometric properties of biological cells at rates exceeding 500 cells per second. Preliminary observations of human cells from different sites in the body were made at wavelengths of 2537 and 4100 angstroms to estimate cellular nucleic acid per unit volume of individual cells of large populations of cells. Display patterns were obtained which were consistent, and characteristically different for certain of the cell populations studied.