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12 Cards in this Set
- Front
- Back
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3 advantages to molecular methods
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1. detect small numbers
2. detect organisms that cant be cultured 3. assays are fast (theretically) |
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Four disadvantages to amplification methods
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1. must have characterized nucleic acid target
2. must interpret the meaning of positive test 3. False positives (contamination) 4. time not always fast |
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amplification format that involves a unique target.
uses amplification to detect the smallest possible number of target molecules. most sensitive, but may be useful only when detection of any evidence of organism correlates with disease |
Qualitative
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amplification format that measures abundance of target
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quantitative
(viral load) - use of technique that generates a graded signal that correlates with target number. useful follwoing therapy. may also be useful in trying to sort out endogenous carriage from Disease |
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4 techniques for amplification
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PCR, TMA (transcription mediated amplification), LCR (ligase chain reaction), bDNA (branched chain DNA amplification
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specimen type used for TMA diagnosis of chlamydia and Gonorrhea
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endocervical, urethral, urine
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TMA (transcription mediated amplification) can be used not only to diagnose symptomatic STD but to
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screen asymptomatic populations
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used to identify isolated colonies in solution
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hybridization
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Two techniques to compair strains for epidemiology
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1. PFGE (pulsed field gel electrophoresis)
2. RFLP |
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two things used to identify an unknown organism
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1. hybridization
2. PCR and sequencing |
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a low positive predictive value (low PPV) means that
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all positives must be confirmed using alternative target
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process of Pulsed-Field Gell Electrophoresis
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1. rare cutting restriction enzyme to make large fragments of bacterial DNA
2. separte fragments by gell in electrical field 3. create pattern of 10-20 bands 4. compare patterns of organism for relatedness |
