16 Questions
What is the purpose of the Guthrie bacterial inhibition assay described in the text?
To screen for phenylketonuria in newborns
What is the significance of maintaining an infant on a diet containing very low level of phenylalanine and high levels of tyrosine?
It prevents brain damage and seizures in infants
What is the consequence if phenylketonuria is left untreated?
Brain damage and progressive mental retardation
Why is it crucial to detect phenylketonuria at birth?
To prevent irreversible brain damage and mental retardation
What is the role of phenylalanine in the Guthrie bacterial inhibition assay?
It counteracts the antagonists and allows bacterial growth if present in high levels in the blood sample
What is the consequence of brain function deterioration starting in the second or third week of life in infants with untreated phenylketonuria?
Progressive mental retardation
Which method is not affected by the presence of antibiotics?
Microfluorometric assay
What is used for prenatal diagnosis and detection of carrier status in families with PKU?
DNA analysis using cloned human PAH cDNA
What does the fluorescence measurement in the microfluorometric assay rely on?
Complex formed of phenylalanine-ninhydrin-copper in the presence of dipeptide
What is the purpose of the urine testing for phenylpyruvate?
Monitoring dietary therapy
What is the role of HPLC or tandem mass spectrometry (MS/MS) in quantitative methods?
Quantitative measurement of phenylalanine
What does the dried blood spot test require as pretreatment of the filter paper specimen?
TCA (trichloroacetic acid)
How does the direct measurement of phenylalanine in dried blood spot differ from urine testing for phenylpyruvate?
Sample collection method
What does the reagent strip test involve?
Reaction of ferric chloride with phenylpyruvic acid in urine
What is used for analyzing numerous restriction fragment length polymorphism in the PAH gene?
Cloned human PAH cDNA
What is required for quantitative methods like HPLC or tandem mass spectrometry (MS/MS)?
Extraction with trichloroacetic acid (TCA)
Test your knowledge about Phenylketonuria (PKU), a genetic disorder that can lead to progressive mental retardation and brain damage if left untreated. Learn about the importance of early detection and specialized diet to prevent irreversible damage.
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