Steps for Tissue Processing to Produce a Permanent Slide of a Tissue Section for Light Microscopy - Essay Example

?DISCUSS THE RATIONALE FOR THE STEPS USED IN TISSUE PROCESSING TO PRODUCE A PERMANENT SLIDE OF A TISSUE SECTION FOR LIGHT MICROSCOPY Introduction Tissue processing is an exceptionally critical aspect in pathology practice. Tissue processing is essentially the second step in histology process. Tissue process entails the diffusion of several substances out of and into stable porous tissues. The clinical use of tissue processing is always intended at generating thermodynamic tendency that can equalise concentration found either outside or inside a block of tissues (Shi, Cote and Chaiwun 1999, p.96). Tissue processing is the comprehensive study of the anatomy of tissues and cells of animals and plants through the use of a microscope. Tissue processing is performed commonly by examining tissues and cells by staining and sectioning which is followed then by examination under an electron microscope or a light microscope (Weiss, Delcour, Meyer, Klopfleisch 2010, p. 833). There are various effects of tissue processing which include the comprehensive diagnosis of the stabilised tissues as well as embedding applications and media. The stabilised tissues should be supported adequately prior to being sectioned for the microscopical examination. The tissues are mainly sectioned after a variety of preparatory freezing methods where the tissues are taken commonly on various reagents. Finally the tissues are infiltrated and embedded in a medium that is stable which when is evidently hard; it necessitates the support for microtomy (Shi, Cote and Chaiwun 1999, p.94). The requirements for light microscopy include the resolution of the magnification, the Imaging and magnification of the microscope, the numerical aperture and the illumination. There are various techniques that are applicable in light microscopy and they include transmitted light microscopy, bright field microscopy, dark field microscopy, phase contrast, polarised light microscopy, differential interference contrast, fluorescence microscopy as well as confocal microscopy. In this process, the light microscope is incredibly critical in examining whether the concentration that is inside a block of tissues is comparable to the one that is outside a specific block of tissue. Tissue processing follows five main stages, fixation, processing, embedding, sectioning, and staining (Weiss, Delcour, Meyer, Klopfleisch 2010, p. 835). Fixation The core aim of fixation in pathology practice is to store tissues in a life like state. Fixation is carried out immediate after the removal of a tissue from the body. For instance, in the case of surgical pathology, fixation takes place immediately after removing the tissue. Chemical that are used in fixation depends on the type of tissue that is undergoing fixation. However, some of the universally used chemicals include formaldehyde, picrates, aldehydes and alcohols (Drury and Wallington 2009, p. 51). Dehydration Dehydration in tissue processing entails eliminating fluid and water that is contained in body tissue. The removal of water in the tissue enhances effective embedding process. In this stage, body tissues are dissolved in dehydrating fluid for dehydration. For instance, lipids are in most cases dissolved in lower aqueous alcohols. Other commonly use chemicals in dehydration include diethoxyproprane and dimethoxypropane (Taylor,Shi, Chen, Young, Yang, Cote 2007, p. 245). Clearing This is the transition step between infiltration and dehydration. Some of the common used chemicals in this stage are wax and paraffin. In this stage, some solvents may have high refractive indices thus interfering with the entire tissue processing. Therefore, this step helps in dealing with tissues that have refractive indices (Shi, Key and Kalra 2011, p.729). Embeddings The embedding process is incredibly essential in the entire tissue processing. This is due to the fact that, embeddings entails aligning and orienting tissue blocks in paraffin. On the other hand, embeddings plays an incredibly vital role in the preservation of tissues. Some of the commonly use chemicals in this stage include epon, paraffin, methacrylate, and araldite (Momose, Mehta, and Battifora, 2009, p. 74). Microtomy This process is very indispensable as it entails the selection of tissue segment. This stage requires special and expensive reagents for clearing and dehydration. In this stage, a special microtome is significant in enhancing the selection of tissue blocks in order to make small biopsies such as liver and bone marrow (Taylor,Shi, Chen, Young, Yang, Cote 2007, p. 263). Unstained slides In this case, a glass slide is placed in warm water for relatively 15 minutes in order to assist the sections to comply with the slides. This process required high temperature. This high temperature my therefore harm the antigens for immunostaining. Therefore, some health professionals talks about the importance of bypassing this step an instead use glue-coated slides in picking the selection (Momose, Mehta, and Battifora, 2009, p. 77). De-waxing This process entails elimination of wax in body tissues. The commonly use chemical in this stage is haematoxylin. De-waxing ought to be effective in order to eliminate all stains in the body tissues. Therefore, de-waxing process requires a lot of time and fresh solvent (Shi, Key and Kalra 2011, p.741). Rehydration Rehydration has to do with the process of increasing water concentration in the dehydrated tissues. Rehydration therefore has to with placing body tissues in less concentrated substances. In most cases, the most effective rehydration chemical is water and les concentrated solutions (Drury and Wallington 2009, p. 67). Staining The staining process entails utilisation of assortment of dyes. The selected dies must have the ability to stain numerous cellular components that is found in a tissue (Elias 2003, p. 17). Some of the commonly used stains in tissue process are hematoxylin. In this stage, the mounted section is effectively treated with the most effective histology stains. In addition, staining is done naturally by placing hematein solution in a shelf for specified period of months (Grizzle 2001, p. 213). Permanent Mount This process includes covering the stained section with a piece of glass or plastic in order to protect the tissue from being scratched. The aim of this process is to offer better optical quality of examining and viewing the tissue under a microscope. Permanent mount is also aimed at ensuring that tissues are protected for specific period of time. In this stage, the stained tissue is passed through alcohol solution in order to eliminate excess water (Ryter 1988, p. 23). The immune response is the immune system reaction towards body intruders. The immune system is the system of biological processes and structures within an organism which effectively protects against a disease. In order for the immune system to function properly, it must be able to detect numerous varieties of agents from parasitic worms to viruses and also be able to distinguish them from the healthy tissue of the organism. The fundamental purpose of the system is to keep off infectious microorganisms such as viruses, bacteria and fungi from the body and to effectively destroy them. The immune system is made up of vital and complex organs and cells networks which protect the body against infection. The lymphoid organs are involved in the immune system and they affect the development, growth and the lymphocytes release. The role differences in the immune response depend largely on the organism ability to detect the foreign bodies. Each organism has its own unique immune system that is also affected by the health-being of the organism. The healthier the organism, the stronger the immune system becomes (Grizzle 2001, p. 192). Summary The structural preservation quality that is normally evident in the final mounted and stained section is more or less determined mainly by the choice of embedding and fixative medium. During the process of tissue processing, the loss of cellular constituents and distortion or shrinkage should be minimal. There are paramount variables in tissue processing and they include particular temperature, operating conditions, the concentrations and characteristics of the reagents and the tissue properties. Agitation, pressure and temperature reduce the tissue processing duration as well as ensure the improvement of the quality of infiltration. Tissue processing is a common state of affair among modern pathologists. Despite offering a lasting solution in the pathology practice, tissue processing has as well offered a essential solution in tissue protection. Scholars have therefore asserted that, the invention of tissue process is a landmark achievement in healthcare practices. Tissue processing is one the other hand very essential in preservation of body tissues. Clinicians therefore use tissue processing in preserving tissues. Moreover, to provide a permanent slide, pathologist must comply with the requirement of tissue process. Some of the commonly used stages in tissue process entail fixing, processing, embedding, sectioning and staining. Every stage is interdependent on each other. Therefore, the success of one stage determines the success of the subsequent stage (Friedrich Moyles and Beveridge, 2000, p. 2209). References Drury RAB, and Wallington EA, 2009, “Carleton’s Histological Technique. 5th ed” Oxford: Oxford University Press Elias J. 2003, “Immunopathology: A Practical Approach to Diagnosis. 2nd ed.”, Chicago, IL: ASCP Friedrich, CL; D Moyles, TJ Beveridge, 2000, “Antibacterial Action of Structurally Diverse Cationic Peptides on Gram-Positive Bacteria” Antiomicrobial Agents and Chemotherapy 44 (8): 2086–2209 Grizzle W. 2001, “The effect of tissue processing variables other than fixation on histochemical staining and immunohistochemical detection of antigens”, The Journal of Histotechnology 20, 24; 213-219. Momose H, Mehta P, and Battifora H., 2009, “Antigen retrieval by microwave irradiation in lead thiocyanate” Application of Immunohistochem.1 (1):77-82. Ryter A., 1988, “Contribution of new cryomethods to a better knowledge of bacterial anatomy". Ann. Inst. Pasteur Microbiol. 139 (1): 33–44 Shi SR, Cote RJ, Chaiwun B, et al.1999, Standardization of immunohistochemistry based on antigen retrieval technique for routine formalin-fixed tissue samples. Application Immunohistochem, 6(2):89-96. Shi SR, Key ME, Kalra KL. 2011, “Antigen retrieval in formal in fixed, paraffin-embedded tissues: an enhancement method for immunohistochemical staining based on microwaveoven heating of tissue sections”, Journlas of Histochem Cytochem., 39(6):741-748. Tacha D, Teixeira M., 2002, “History and overview of antigeretrieval: methodologies and critical aspects”, Journals of Histotechnology 25(4):237-242. Taylor CR, Shi SR, Chen C, Young L, Yang C, Cote RJ. 2007, “Comparative study of antigen retrieval heating methods: microwave, microwave and pressure cooker, autoclave, and steamer” Journals of Biotech Histochem, 71(5):263-270. Weiss AT, Delcour NM, Meyer A, Klopfleisch R., 2010, “Efficient and Cost-Effective Extraction of Genomic DNA from Formalin-Fixed and Paraffin-Embedded Tissues” Veterinary Pathology 227 (4): 834–838 Read More