Two Techniqyes in Hospitals Laboratory Essay Example | Topics and Well Written Essays - 2000 words

Two Techniqyes in Hospitals Laboratory - Essay Example This paper summarizes each of these methods and provides examples of their relevance to biomedical research and clinical medicine. Flow Cytometry Analytical flow cytometry (AFC) is used to assess the biochemical composition of cells using an optical scanner in the assessment of individual cells as they are screened individually at a rapid rate (approximately 100 cells per second) through an optical scanner (Boddy et al 2001; Givan 2001). This methodology permits quantitative measurements of molecular components within each cell individually (Davey & Kell 1996; Givan 2001). An important medical use of AFC is the identification of specific strains of infectious bacteria in infected cells obtained from patient biopsy (Boddy et al 2001). Once the pathogen is identified, AFC is also used in therapeutic assessment of antibiotics on the clinical course of infection by examining patient cells by AFC post-treatment. In this regard, AFC is an important biomedical tool in the assessment of para meters of clinical sensitivity and resistance of specific bacterial strains to specific therapeutic regimens (Davey & Kell, 1996). In addition, AFC can be used to measure the cellular DNA and protein concentration and the activity of specific enzymes (Roederer 2001). The capability of AFC to assess molecular content within individual cells involves the use of fluorescence measurements to characterize the biochemical components of cells. In this technique, fluorescent probes are applied to specific cell molecules which are then assessed via the detection of optical excitation patterns emitted by these optically labeled cell components. (Shapiro 2003). These optical excitation patterns emitted by the fluorescently labeled cell components can be used to pinpoint specific types of molecules and to quantitate their concentrations within the cell (Shapiro 2003). This accuracy is facilitated by the standardization of controlled flow by means of hydrodynamic focusing methods (Shapiro 2003). Further analytical sophistication can be achieved by the use of multiple optical beams and two channel detectors to detect two different cellular signals at the same time in the same scan while providing a high sensitivity (Zhong et al 2005). Labeled nanoparticles are also be utilized as probes in the molecular assessment of cell composition (Zhong et al 2005). In addition to biochemical composition, AFC can be used to assess cell proliferation by means of accurately identifying cell cycle composition of dividing mitotic cells. This assessment can be carried out in individual cells (Pozaroski & Darzynkiewicz 2004). This method requires the DNA binding dye propidium iodide (Shapiro 2003). DNA and protein content can be assessed simultaneously in individual cells by means of bivariate analysis and comparisons between normal cells and tumor cells (Pozaroski & Darzynkiewicz 2004). This technique also permits the evaluation of cell viability on an individual basis and can distinguish ce ll death resulting from apoptosis versus necrotic mechanisms (Bertho et al 2000). Apoptosis results in a characteristic cell fragmentation into small apoptotic bodies containing fragmented DNA segments; this process can be detected by AFC and distinguished from plasma membrane degradation which is characteristic of necrotic cell death mechanisms. Cell viability measurements are an important component of disease assessment with regard to the identification of pathogenic mechanisms that may cause cell