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39 Cards in this Set
- Front
- Back
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what do you sterilize instruments with?
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70% alcohol
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define "cell culture"
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the growth and maintenance of living cells in semi-artificial media under sterile conditions
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T/F viruses replicate readily in vitro.
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true.
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briefly explain how cell culture is done.
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tissue organization disrupted by adding trypsin + EDTA to minced tissue ->disrupted cells spun out and suspended in medium for growth on glass/plastic containers.
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why is EDTA used in cell culturing?
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it's a chelating agent that removes divalent cations from the solution that interfere with the action of the trypsin and contribute to tight cell adhesion.
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why is plastic used as opposed to glass in cell culture these days?
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disposable, easy to sterilize
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what are the basic 6 ingredients in a growth medium BESIDES serum?
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AA's, vitamins, glucose, inorganic salts, buffer, antibiotics
VIA BAG |
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whats the most commonly used source of growth factors added to growth media and how much is added?
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serum. 5-15%.
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how are cell cultures categorized?
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according to the source of cells and their passage potential
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define primary and secondary culture
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primary = first culture prepared from the originally disrupted tissue
2ndary = first subpassage of the primary culture |
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define cell strain and cell line
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cell strain = cell culture that can be subpassaged for a finite period of time remaining diploid
cell line = a cell culture that has changed into a cell type with unlimited life span |
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what type of cells are usually cultured in suspension (as opposed to monolayer)
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lymphoblastoid
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how are cell strains/lines subpassaged? what temperature are the incubated at and what does the container have to do with anything?
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trypsinization, dilution then reseeding and incubated at 37C. if using a loosely capped container (petri dish) you need 5% CO2 for pH maintenance.
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what are the 4 approaches to viral infection diagnosis?
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1) isolate/ID the virus
2) detect viral components (proteins/nucleic acids/enzymes) 3) show rise of Ab to particular virus 4) histopath |
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when should you collect specimens for virus isolation and why?
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EARLY. because highest titer is present.
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when should you draw serum for serology and why?
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acute and convalescent aka before 7th day and after 14th day.
want to show increase in Ab titer within the same test. |
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how much serum do you need for serology test?
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1-4 mL
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T/F blood collected for serology should be allowed to clot before spinning.
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true.
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how long can you keep serum in the fridge?
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several weeks.
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T/F you need to take tissue specimens from grossly abnormal tissue.
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TRUE. need abnormal AND normal.
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T/F cells in culture have a micro-immune system.
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false. i made that up. CELLS IN CULTURE HAVE NO IMMUNE SYSTEM.
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why do we add Abx. to cell culture?
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because the cells don't have any immune system.
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how long can tissue specimens be kept on ice? what about longer than this?
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24 hours.
any longer = freeze |
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where's the best place to get pharyngeal swabs?
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the tonsillar area at the BACK of the pharynx.
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where do you swab eyes?
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conjunctiva.
not the retina. |
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how do you get vesicular fluids for testing?
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FNA
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what's the most common procedure done to test fecal samples for virus?
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negative staining electron microscopy of pelleted virions from the feces.
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T/F you don't need many virions in a fecal to get a +.
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false. you need a high titer (immediately after clin signs is usually fine)
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T/F convalescent samples are useless for fecal viral analysis.
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true.
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how do you keep feces from an acutely ill animal for a while?
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tx with 10% NBF 9:1 and put it in the fridge (4C)
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what would a 4 fold increase in antibody titer mean for the host?
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the host is mounting an immune response.
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how do you ID an isolated virus?
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it's CPE or immunological probes
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what are 3 advantages to using cultured cells instead of an intact organism?
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each culture is a separate "host"
changes can be easily seen via microscope small cultures can be cheaply used to check a lot of samples |
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T/F some viruses that replicate in culture do not cause CPE so ID'ing them is tough.
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true.
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T/F inability to isolate a virus excludes it from involvement in pathogenesis of a disease.
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false.
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T/F ELISAs are very specific
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true.
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what's the main advantage of ELISA for parvo?
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can be run using fecals directly w/o interference from the bacT.
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what are 3 indications for virus replication?
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death of the embryo
production of pocks (membrane foci of infection) other means |
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how long do you incubate the SIV for in the egg?
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48h
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