Mass Spec & Tumor markers Flashcards
What is mass spectrometry (MS)?
A powerful analytical technique used to identify unknown compounds, determine concentrations of known substances, and study molecular structure and chemical composition.
MS can detect drugs, steroids, damaged genes, dioxin, proteins, and metabolites.
What are the three main components of a mass spectrometer?
- Ionization source
- Mass analyzer
- Ion detection system
What is the role of the ionization source in mass spectrometry?
Converts molecules to gas phase ions that are manipulated by a magnetic field into the mass analyzer.
What techniques are used for ionization in mass spectrometry?
- Electron ionization
- Chemical ionization
- Electrospray ionization
- Matrix-assisted laser desorption/ionization (MALDI)
What does the mass analyzer do?
Sorts ions based on their mass to charge ratio (m/z).
What is the mass to charge ratio (m/z)?
The mass to charge ratio is obtained by dividing the atomic or molecular mass of an ion by the number of charges the ion bears.
How is a mass spectrum plotted?
Mass to charge ratio is plotted along the x-axis and the relative abundance is on the y-axis.
What is the purpose of combining mass spectrometry with separation techniques?
Aids in substance identification by allowing for better analysis of complex samples.
What does MALDI stand for?
Matrix-assisted laser desorption ionization.
What is the purpose of the MALDI technique?
To ionize samples for mass spectrometry analysis.
What is the function of the TOF mass analyzer?
Determines m/z ratios by measuring the time it takes ions to travel to the detector.
What is diagnostic sensitivity?
A measure of how often an assay detects a biomarker when the disease is present.
What is diagnostic specificity?
The probability that a laboratory test will be negative in the absence of disease.
What does Bayes’ theorem help calculate?
Updates the probabilities of hypotheses when given evidence.
What are tumor markers?
Measurable biochemicals associated with malignancy, produced by tumor cells or in response to them.
What is the main use of tumor markers in clinical practice?
Support diagnosis and monitor treatment response.
What are the advantages of using tumor markers?
- Aid in cancer diagnosis
- Monitor treatment response
- Serve as prognostic indicators
- Indicate relapse
What are some disadvantages of tumor markers?
- High variability in patient samples
- Lack of reliability
- Presence in non-cancerous conditions
What is alkaline phosphatase (ALP)?
An enzyme responsible for dephosphorylating compounds, primarily sourced from liver, bone, and intestine.
What conditions may elevated ALP indicate?
- Liver cancer
- Osteoblastic lesions related to prostate cancer
- Breast cancer with bone metastases
What is the role of creatine kinase (CK)?
Plays a role in energy production by catalyzing the conversion of creatine and using ATP to create phosphocreatine.
What conditions may elevated CK indicate?
- Small cell lung carcinoma
- Prostate cancer
What is Creatine Kinase (CK)?
Enzyme that plays a role in energy production, catalyzes the conversion of creatine and uses ATP to create phosphocreatine.
Principal sources are high energy tissues like heart muscle and brain.
What conditions can elevated Creatine Kinase (CK) indicate?
- Small cell lung carcinoma
- Prostate cancer