Particle agglutination test

Particle agglutination test The presence of an antigen or anti-bodies in a blood sample can be found out using either the Particle Agglutination Test (PAT) or by the Enzyme-Linked Immunosorbent Assay (ELISA). The PAT is performed using substances that will facilitate the process of agglutination. Agglutination is the clumping together of particles which forms non-dissolvable or what is called as insoluble aggregates. The common substances used in the PAT are latex particles, preserved blood cells from mammals or birds, colloidal particles, and gelatine beads. The different components used in the PAT are microscope slides or test cards and a solution that facilitates agglutination which is made up of molecules that are analyte-specific which is attached to a constituent part or particle. In a test using ELISA detects the presence of an antibody or antigen by affixing an undetermined amount of antigen to a test surface which in turn is washed by a specific antibody in order to attach it to the antigen. Because of this process the antibody becomes linked to an enzyme that will show a certain detectable signal after a substance is added to it during the final steps of the process. The signal emitted differs from what type of ELISA is used. For example a fluorescent ELISA a light of a correct wavelength that is shone on a sample will elicit a response from the antigen/antibody which will show incandescence. The antigens amount contained in the sample is then determined based on the intensity or magnitude of the samples incandescence. While the PAT relies on the clumping together of particles to show the presence of an antibody, the ELISA is a more complex test which can only be performed following very specific protocols or steps to perform. In ELISA an antigen with an undetermined amount is rendered immobile while place on a polystyrene microtiter plate or other substance that could provide a solid support and which does not interfere with the purity of the sample. The antigen is immobilized either by adsorption; the adhesion of molecules to a surface, or by capturing the particles of the antigen by another antibody that is particular to the same antigen. The process of adsorption is what is termed as non-specific immobilization while the capture of the antigen is what is termed as specific immobilization. After the immobilization of an antigen the next step is to add a detection antibody. The addition of this antibody results in the formation of a complex with the existing antigen. The detection antibody can either be linked directly to an enzyme, or it can be noticed by a secondary antibody that is connected to an enzyme by a process called bioconjugation this occurs when two biomolecules couple with each other in a chemical bonding wherein the two substances share pairs of electrons, or what is known as covalent bonding. In between each step of the process the plate used is washed in a solution of mild detergent so as to remove any antibodies or proteins that have not bonded specifically. After the plate undergoes its final wash it is then developed using an enzymatic substrate, which means the enzyme has a molecule which it acts on. This enzyme substrate when added will produce a noticeable signal indicating how much the quantity of an antigen is in a given sample. The PAT and ELISA are but two of the techniques used in laboratories in serology. Other techniques include gel diffusion tests, precipitation tests, agglutination tests to which PAT belongs, immunological tests with markers which ELISA is one of the tests, and lastly there is the immunosorbent electron microscopy. To further discuss the comparisons and contrasts of the ELISA and PAT let us discuss the general aspects of the two tests. As was mentioned above both ELISA and PAT are techniques used in serology to detect the presence of antibodies and antigens in a sample. However the two tests differ in the process or steps taken to obtain the same results. PAT is an agglutination test. This means that its primary method to determine the presence of antibodies is by inducing the clumping or joining together of molecules in the test sample by either by using substances that are inert which carry the antigens or antibodies, or by using polystyrene spheres infused with immunoglobulin molecules, or by observing the loss of activity of antigens or what is called as neutralization. What is observed by serologist when using PAT is the reaction called agglutination, which is a reaction that leads to the joining together or clumping of a specific antibody in a cell suspension as a reaction to a specific antigen. While in ELISA what is observed is not the reaction of an antibody to the antigen but the level of activity made by the substance or markers chemically bound together to the antigen and antibody which in turn indicates the antibody antigen reaction. The PAT test was one of the first serological methods that was developed and which helped pave the way for developing diagnostic techniques and countermeasures to diseases. One early agglutination test is the Widal agglutination. The Widal agglutination, which was named after Fernand Widal, aided in the diagnosis of typhoid fever by showing the presence of an antibody in a sample obtained from an infected patient, in reaction against the antigens of the Salmonella typhi. What the Widal test did was to increase the suspicion of infection because of the presence of agglutination caused by a rise in of antibodies during the period of infection. In the classic test for agglutination the process starts by placing a specimen in a microscope slide or a microtest plate well where the particles which act as carriers are added. This mixture is then stirred or disturbed and then it is given a few minutes to settle or is incubated. The results can be gleaned by observing agglutination as the carrier particles fuses or binds with the particular analytes contained in the sample. The results are seen visually by the naked eye or by using a microscope depending on the format of the test. Interpreting test results are relatively easy if the reactions are strong. But in cases where there is a weak or minor reactions interpretation is quite difficult and in most cases may depend upon the wealth of experience and practice one has. In microwell plate assays, the resulting patterns produced by the particles after it has settled need an educated interpretation before the result can be determined. The advantages of PAT are it is low cost, semi-quantitative tests results can be obtained, and test results are obtained in a relatively short span of time. The disadvantages are there is a need to be very careful in the interpretation of marginal results. There is also the disadvantage related to problems that may arise in relation to specificity because substances that may interfere in many assays. Unlike PAT, ELISA is a more reliable method which uses biochemicals to measure how much of a given substance in a biological liquid such as serum or urine mixes with another substance. This is done by means of the reaction that an antibody or antibodies has to its antigen which is a molecule that is identified by the immune system. The antigen always specifically binds itself to an antibody at the molecular level. Since ELISA can be used to test and identify the presence of an antigen or of an antibody in a sample, this method is a very useful tool to determine concentrations of serum antibodies such as when testing HIV and other viral diseases. ELISA is also helpful in determining potential allergens in food such as milk, eggs and nuts. ELISA is also used in toxicology as a presumptive screen that is used for particular classes of drugs. Since lab technicians, serologists, and other medical personnel conducting the PAT and ELISA tests are exposed to samples that might contain viral or bacterial strains, the need to ensure safety and also the purity of the samples through a high standard of quality necessitates developing certain protocols for laboratory work. Different hospitals and government departments dealing with lab samples have already developed their own manual or standards that must be observed while working with lab samples to ensure safety. The manual issued by the Industrial Accident Prevention Association identifies potential hazards inside the lab brought about by chemical and biological agents, physical agents, the equipment and apparatus, and doing work that results in non-ergonomic movement and postures. The manual also discusses the ways by which to control or lessen the danger posed by these hazards and what are the steps that should be taken to have a safe lab environment. The Mount Sinai Hospitals Microbiology Department also has its own guidelines and policies which specifically deal with laboratory safety. The manual discusses the safety policy of the hospital and what are the protocols to be observed. These protocols include dealing with visitors to the lab, what constitutes good lab practice, how to ensure biological safety, chemical safety, physical hazards, specimen hazards, and what control, emergency, and preventive measures should be followed to realize laboratory safety. These and other similar measures contained in other manuals may vary from lab to lab, but the essence remains the same; that is to promote safety and institute standards of work that ensures an accident and hazard free lab environment. REFERENCES: Adler M., Schulz S., and Spengler M., (n.d.). Cytokine Quantification in Drug Development: A comparison of sensitive immunoassay platforms. A case study conducted for Chimera-Biotech. Retrieved on March 29, 2010 from the World Wide Web: chimera-biotec.com/data/pdf/Cytokine_Quant_Comp_Final.pdf True K., (2004). Enzyme Linked Immunosorbent Assay (ELISA) for Detection of Renibacterium salmoninarum Antigen in Fish Tissue. (June 2004). NWFHS Laboratory Procedures Manual Second Edition. Chap.6 pp. 1-33. Retrieved on March 29, 2010 from the World Wide Web: www.fws.gov/canvfhc/WFSM/CHP6.pdf (N.d.). TECHNIQUES IN PLANT VIROLOGY CIP Training Manual 2.3 DETECTION/Serology. Retrieved on March 29, 2010 from the World Wide Web: www.cipotato.org/csd/materials/PVTechs/Fasc2.2.3(99).pdf Katti M., (1999). Ideal Carrier Particles for Agglutination Tests. (June 1999). JOURNAL OF CLINICAL MICROBIOLOGY, Vol. 37, No. 6, p. 2120, 0095-1137/99/$04.0010. Retrieved on March 29, 2010 from the World Wide Web: jcm.asm.org/cgi/reprint/37/6/2120.pdf (2008). Laboratory Safety. Published by the Industrial Accident Prevention Association. Retrieved on March 29, 2010 from the World Wide Web: www.iapa.ca/pdf/labsafe.pdf

Art versus Pornography Essay -- Argumentative Persuasive Topics

Art versus Pornography   Ã‚  Ã‚  Ã‚  Ã‚   Her head rests on her left knee, with her hands clasped on her ankle.   Locks of hair are thrown about in an auburn blaze.   Her tight rosy lips are as red as her cheeks.   Her dark-blue eyes reveal a half-seductive, half-submissive look.   Her legs are in a subdued spread-eagle formation, leaving her crotch area quite visible.   Her white panties leave little to the imagination. The sexual overtones are more than just a coincidence.   Ã‚  Ã‚  Ã‚  Ã‚   Suspend your imagination for a minute and ask yourself if the description formed in your mind a work of art or, instead, a photograph of softcore pornography, found in such magazines as Hustler or Playboy?   Where this description is taken from will be disclosed later, but let us concern ourselves with a problem that this... ...ed them.   A person at the time looking at his works would recognize them as prostitutes, a fact that is less distinct today.   His display of the "product" in some cases, could be seen as propaganda against prostitution.   Hence, he had an intellectual, not a pornographic intent.  Ã‚   This debate will continue, and perhaps no end may come of it until viewers have understanding of the artist's intent.

Review Questions for Business Management Essay

1) What is resource overallocation? Resource leveling is the project management function of resolving project resource over-allocation. By definition over-allocation means that a resource has been assigned more work than can be accomplished in the available time as dictated by the resource’s calendar definition. In most scenarios, over-allocations can be remedied manually by extending tasks or moving them to accommodate the resource’s availability 2) What is resource leveling? When performing project planning activities, the manager will attempt to schedule certain tasks simultaneously. When more resources such as machines or people are needed than are available, or perhaps a specific person is needed in both tasks, the tasks will have to be rescheduled concurrently or even sequentially to manage the constraint. Project planning resource leveling is the process of resolving these conflicts. It can also be used to balance the workload of primary resources over the course of the project[s], usually at the expense of one of the traditional triple constraints (time, cost, scope). 3) Under what circumstances would you want to manually resolve conflicts? You can resolve resource conflicts or overallocations by using the resource-leveling feature in Microsoft Office Project. Leveling works by splitting tasks or by adding delay to tasks until the resources that are assigned to those tasks are no longer overloaded. Because of these changes to the tasks, leveling can delay the finish date of some tasks and consequently also the project’s finish date. When it is leveling, Project does not change who is assigned to each task 4) What would be the caution of adding more resources to a task to resolve resource conflicts? As you assign resources to tasks, Project checks the resource’s calendar to make sure that the resource is working. However, Project doesn’t assess whether the resource is already obligated when you assign the resource to a new task; Project enables you to make the assignment. Be aware, though, that the additional assignment may lead to overallocating the resource. Overallocation occurs when you assign more work to a resource than the resource can accomplish in the time that you’ve allotted for the work to be completed. 5) What would be the caution of rescheduling a task to resolve a resource conflict? To get the best performance and results from resources (resources: The people, equipment, and material that are used to complete tasks in a project.), you must manage resource workloads to avoid overallocations (overallocation: The result of assigning more tasks to a resource than the resource can accomplish in the working time available.) and underallocations (underallocation: Assigning a resource to work fewer hours than the resource has available.). If you change resource assignments (assignment: A specific resource that is assigned to a particular task.), check the effects of your changes on the overall schedule (schedule: The timing and sequence of tasks within a project. A schedule consists mainly of tasks, task dependencies, durations, constraints, and time-oriented project information.) to make sure that the results meet your project goals.

Red’s Redemption- Shawshank Redemption - 1169 Words

The Shawshank Redemption follows the lives of Ellis â€Å"Red† Redding and Andy Dufresne and their twenty-year stint at the Shawshank State Penitentiary. Red (a guilty man) is serving a life sentence for murder, Andy (an innocent man) is serving consecutive life sentences for the murder of his wife and her lover. Throughout the film, Red and Andy form an unlikely friendship that transcends age, race, and class boundaries that ultimately leads to Red’s spiritual redemption and freedom. The film is set up for a classic white and black pairing with a â€Å"magical negro† narrative, however, The Shawshank Redemption subverts expectations. 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