Biological Sciences
Measuring Cells
Measuring cells involves quantifying various cellular properties such as size, shape, and function. This can be done using a variety of techniques including microscopy, flow cytometry, and biochemical assays. Accurate measurement of cells is essential for understanding their behavior and function in biological systems.
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6 Key excerpts on "Measuring Cells"
eBook - PDF- C Hawes(Author)
- 2012(Publication Date)
- Academic Press(Publisher)
The structural framework which has made this progress possible was provided by microscopists, who have described the formation (division) of cells, their development, differentiation and location in tissues and organs of living systems. It is tempting to believe that this descriptive phase of cell biology is now drawing to a close, in favour of an approach 'at the molecular level'. This is unfortunate since microscopists should be encouraged to assist molecular biologists in their efforts to place this new information in the context of a living, functioning cell. Quantitative morphological analysis provides a means for translating the visually apparent structure into numerical data that can be subjected to the powerful methodologies of mathematics, and integrated with numerical information from other sources. The numerical expression of morphological information can be useful as an adjunct to the description of various cell types. It is more useful when employed in the assessment of the effects of experimental treatment on cells, tissues and organs, or when trying to interpret the functional significance of physiological and biochemical data (for example, mitochondrial struc-ture and respiration rate). As a counterbalance to the complexities of the techniques used in microscopy (or do we all take electron microscopes for granted?) we will find that quantitative analysis of micrographs is a relatively simple process that requires little additional effort. The greatest problem, for beginners, is to understand clearly the nature of the information that is available, and the methods used for obtaining it. 3.2. UNDERSTANDING YOUR SPECIMEN We should start by considering the specimen chosen for microscopy. This is usually an organ or tissue, less often the whole organism. The microscope image will contain details of various cell types (each extending to its boundary, the plasma membrane) within the organ, together with the external spaces, cavities, etc.
eBook - ePubAdvanced Optical Flow Cytometry
Methods and Disease Diagnoses
- Valery V. Tuchin(Author)
- 2011(Publication Date)
- Wiley-VCH(Publisher)
1 Perspectives in Cytometry Anja Mittag and Attila Tárnok 1.1 BackgroundCytometry is the general term for quantitative single cell analyses. Without cytometric analyses, work in modern life sciences would be unthinkable. Since its introduction, cytometry has been influencing and promoting development in biology and medicine. A high number of molecular parameters are analyzable within heterogeneous cell systems by cytometry. If the normality of a heterogeneous cell system is known, changes can be identified. Hence, biological alterations induced by malignancies, infections, and so on, are diagnosable. Such phenotypic changes allow for understanding disease-related (or induced) alterations of molecule expression patterns and hence, the functionality of the whole biological system. This interest to unravel molecular properties of single cells of healthy and diseased organisms (and to compare them) led to the development of the first cytophotometric instruments in the middle of the last century [1].Analyses in those days were usually based on different light absorption capabilities of cell constituents of cells fixed on microscopic slides, with or without staining (e.g., Feulgen). Since these analyses were very time consumptive (5–10 min per nucleus or cytoplasm region), measurements of high cell numbers were simply not possible [2]. This technology was followed by instruments for blood cell counting with a higher throughput where cell concentrations were enumerated by counting electrical voltage pulse during cell transit [3].Application of fluorescence dyes opened the way for obtaining more information per cell. In 1961, the first use of fluorescence for quantitation was reported [4]. Since then, development of new instruments was focused toward fluorescence analysis. In 1969, the first impulse cytophotometer (ICP-11) (Phywe GmbH, Göttingen [5]) was commercially launched where the fluorescence (resulting from mercury arc lamp excitation) of several thousand cells per second was measured by photomultiplier tubes (PMTs). Later, lasers were employed as stable light sources for excitation of fluorescence dyes. The first flow cytometer equipped with two lasers was available in 1976 [6]. Several fluorescence dyes could now be measured simultaneously. The basic principle of this technology is still applied in modern flow cytometers: cells are separated by sheath fluid, (hydrodynamically) focused, and excited by (laser) light in flow. The scattered and emitted or absorbed light is measured.
eBook - PDF- Ellis Meng(Author)
- 2010(Publication Date)
- CRC Press(Publisher)
317 8 Clinical Monitoring 8..1 Flow Cytometry Cytometry is a measurement technique that captures the physical or chemi-cal characteristics of single cells and uses these properties to sort them. Flow cytometry forces cells to flow in a single file past a detection region to facili-tate the measurement of cell properties. These properties guide the electrical or mechanical sorting of cells into proper collection reservoirs. In fact, many biological and nonbiological entities can be analyzed and sorted using flow cytometry including mammalian cells, viruses, bacteria, particles, chromo-somes, lipids, proteins, and ions. In medicine, flow cytometry is an indispens-able tool for blood analysis, isolation of stem cells, detection of malignant cells, immunology, and genetic analysis. It is also an important technique in cell and molecular biology and environmental monitoring. A key feature of flow cytometry is that cells are sorted without the loss of their viability. Early applications of flow cytometry date back to the 1940s, mainly in the area of cell counting. Modern-day conventional flow cytometry systems are capillary based but are still large and bulky. In addition, specialized person-nel are required to operate such tools, and the process is still labor-intensive. Naturally, the exquisite fluid- and cell-handling capability of microfluidics was sought to address the limitations of current cytometric technology. Several excellent reviews exist on the topic, including general reviews [1–3], a focused review on single mammalian cells [4], a focused review on blood cells [5], and a review on cytometric analysis [6]. Here, we focus on the biomedical applica-tions of cytometry. Chemical cytometry, which involves obtaining the chemi-cal composition of single cells, is not covered here. Select topics for chemical cytometry such as mass spectrometry and capillary electrophoresis were cov-ered in chapters 6 and 7. The interested reader is also referred to reference [7].
- A. Mujib(Author)
- 2000(Publication Date)
- Bentham Science Publishers(Publisher)
Flow cytometry is one of the sophisticated tools with its applications in different biological disciplines, including molecular biology, microbiology, cancer biology, hematology, immunology, biotechnology, genetics, plant sciences, cytogenetics, toxicology, pharmacology, and pathology. Cell size, cell count, cell cycle, and other parameters can all be measured using cytometry. Researchers can obtain incredibly detailed information on individual cells using this method. This makes sure that each cell is examined separately.FLOW CYTOMETRY
Flow cytometry (FCM) is a sensitive device that simultaneously measures multiple physical characteristics like the shape, size, and granularity of the cell within a suspension. Characteristics are measured while cell suspension flows through the measuring device. Its effectiveness and accuracy depend upon the light scattering mechanism (forward scattering & side scattering), which is obtained by different specific dyes or monoclonal antibodies targeting intracellular components or extracellular antigens present on the surface of the cell. With this method, flow cytometry has emerged as a potent instrument for thorough analysis/investigation of the complex population within a short period of time.Flow cytometry is one the sophisticated tools with its applications in different biological disciplines, including molecular biology, virology, microbiology, cancer biology, hematology, immunology, biotechnology, genetics, ecology, plant sciences, cytology, cytogenetics, toxicology, pharmacology, embryology and pathology. It is potentially efficient in the characterization of mixed populations of cells present in biological samples, including blood cells, lymphocytes, microorganisms, sperms, cancer cells, metabolites, antibodies, DNA/RNA content, proteins, toxins, plants spores etc [1 ].This chapter discusses the fundamentals of flow cytometry and a few of its applications in the fields of medicine/medical sciences, immunology, diagnosis, microbiology, biotechnology, food science, and plant science. This chapter offers an introduction to flow cytometry technology that is necessary for all end users, researchers, and scientists working in biological sciences. It includes applications in relative biological fields that will help in the advanced analysis of biological samples. Additionally, current developments in flow cytometry have been reviewed to provide insight into the potential significance of this technology.
eBook - PDF- Biba Vikas, Michael Fasullo, Biba Vikas, Michael Fasullo(Authors)
- 2020(Publication Date)
- IntechOpen(Publisher)
Therefore, the growth curve is important in guiding clinical drug usage, investigating gene functions, and understanding drug mechanism of action. Various methods have been developed to measure the absolute number of cells or the changes in cell number, as shown in Figure 4 . 4.1 Manual cell counting Traditionally, cell numbers are counted by taking an aliquot of a homogenous cell suspension and plating on a hemocytometer to count the numbers under a light microscope. The obtained cell number in a certain volume of the suspension is then converted into the cell concentration (cells per ml) in the stock solution. Bacteria are counted by a Petroff-Hausser bacterial counter, a Hawksley counter, and/or the plate colony formation method. The plate colony counting method often gives a lower cell number than the actual value, because it is often difficult to disperse bacteria into a single cell and to make sure that a single colony is not derived from several bacteria. 4.2 Automated mechanical counting The most commonly used automatic cell counting methods are direct electri-cal impedance, flow cytometry, computer-aided image analysis, and serological counting. Through changes in electrical properties, the direct electrical impedance method quantifies the number and the volume of cells in the blood. Using a photo-multiplier to filter and detect the signal, flow cytometry records both the density and height of fluorescent pulses and then converts them to the number of bacteria; the method is fast and sensitive and can simultaneously analyze the cell morphol-ogy and protein biomarkers. Computer-aided image analysis [47] and serology [48] counting methods analyze the image or 2D picture to obtain accurate quantification and morphological structure. So far, both methods have been used successfully in biology, materials science, mineralogy, and neurological science. Figure 4. The main methods for cell growth measurement.
eBook - PDF- James F. Leary(Author)
- 2022(Publication Date)
- Cambridge University Press(Publisher)
A general dictum is that measurements must always be much faster than the rate of the change in the cells to be meaningful – a good thing to always keep in mind! 10.2 Quantitative Single-Cell Measurements of One or More Proteins per Cell One of the most powerful ways of quantitatively measuring the number of specific proteins on or within a single cell is by single-cell flow cytometry. Nanomedicine is 187 10.2 Quantitative Single-Cell Measurements of One or More Proteins per Cell single-cell medicine. Flow cytometry is a technology for measurements on large numbers of single cells. It is a natural wedding of problem and solution! We can measure thousands of individual cells per second and can distinguish between differ- ent types of cells in a cell mixture. For this reason, a great deal of this chapter will discuss the use of flow cytometry to study proteins associated with single cells, including whether those particular proteins are phosphorylated. A flow cytometer in its simplest interpretation is just another type of fluorescence microscope, except that instead of putting cells on a slide we have them flow one at a time past a light source (e.g., a laser beam) and measure different colors of fluores- cence, each marking the presence of a particular molecule on, or within, a single cell (Figure 10.1). 10.2.1 The Power of Multiple Correlated Measurements per Cell While measurement of a single parameter of a cell is powerful, a much more important capability of a flow cytometer is to make multiple correlated measure- ments on the same cell. Such multiparameter measurements are capable of seeing specific cell subpopulations that are otherwise impossible to view. Figure 10.2 shows the power in seeing many more cell subpopulations using only two correlated measurements per cell.
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