Misc. stuff Flashcards
TREM2
Non- mutated gene, allows white blood cells to target and attack beta amyloid plaques in the brain
APO E
Apolipoprotein E= transports lipoprotein, fat soluble vitamins and cholesterol into the lymph then Into the blood. Important in lipoprotein metabolism and cardiovascular disease…. Defects: type III hyperlipoproteinemia (HLP III), in which increased plasma cholesterol and triglycerides are the consequence of impaired clearance of chylomicron, VLDL and LDL remnants
Epigenetics
Regulates gene expression independent o the underlying DNA relying on chemical modification of DNA and histone proteins (histone acetylation). This could bridge genetics and environmental factors.
Genomic Imprinting
Only one of two parental alleles is expressed. These genes are called “imprinted genes”. It is a reversible mechanism because suppressed alleles could be reactivated during gametogenesis. This is explain by DNA methylation.
X Chromosome Inactivation (XCI)
Silencing one of two X chromosomes in females, failure leads to abortion
Rett syndrome
Epilepsy, ataxia (“a lack of order”, lack of voluntary coordination of muscle movements), pt.s are heterozygous females.
MECP 2
Methyl CPG) binding protein 2. Encodes a transcriptional repressor it is related to Rhett syndrome. Mice experiments show that MECP 2 treatments can reverse Rhett’s syndrome.
L1 Retrotransposition
L1 sequence is inserted into various genomic regions when L1 is hypomethylated. MECP2 deficiency accelerates retrotransposition.
Folic acid
Prevents hypomethylation, provides methyl residues essential for maintenance of DNA methylation
Valproic acid
An inhibitor of histone deacetylases
Evaluation of diagnostic tests
Table… Test y axis and disease x axis….plus minus plus minus
Sensitivity and specificity are fixed properties of the test
Positive predictive values and negative predictive values vary with pretest probability or prevalence
Sensitivity
True positive rate…..can tell true positives from all positives…
TP/(TP +FN)
1-false negative rate
Specificity
True negative rate…
out Of all the negatives how many are true negative…
TN/TN+FP
1- false positive rate
Attributable risk
A/(A+B)- c/(c+d)
Y axis risk factor, x axis disease
Difference in risk between exposed group and unexposed group……ie if lung cancer risk in smokers is 21% and non smokers %1 attributable risk is %20.
Number needed to treat
# of pt.s needed to treat for 1 pt. to benefit l. 1/ absolute risk reduction
Absolute risk reduction
Absolute reduction associated with treatment as compared to a control 8% who receive placebo flu vaccine get flu vs. 2% of people who receive flu vaccine. 8-2=6
Relative risk
a(a+b)/ c/(c+d)
Risk of developing disease in exposed group divided by risk in unexposed group… If prevalence is low odds ratio = relative risk
Odds ratio
Case control study odds of diseased group exposed to risk factor vs. odds of group without disease exposed to risk factor.
A/c/b/d
Ad/bc
Major symptoms of depression
SIGECAPS
Sleep changes, loss of interest (anhedonia), Guilt, Energy Loss, Concentration Changes, appetite changes, psychomotor abnormalities, suicidal thoughts
*5/9 of these for 2 weeks or more
Avidin
Avidin’s affinity for biotin is exploited in wide-ranging biochemical assays: western blot, ELISA, ELISPOT and pull-down assays. In some cases the use of biotinylated antibodies has allowed the replacement of radioiodine labeled antibodies in radioimmunoassay systems, to give an assay system which is not radioactive.
Avidin immobilized onto solid supports is also used as purification media to capture biotin-labelled protein or nucleic acid molecules. For example, cell surface proteins can be specifically labelled with membrane impermeable biotin reagent, then specifically captured using an avidin-based support.
Radioimmunoassay
Radioimmunoassay (RIA) is a very sensitive in vitro assay technique used to measure concentrations of antigens (for example, hormone levels in the blood) by use of antibodies. As such, it can be seen as the inverse of a radiobinding assay, which quantifies an antibody by use of corresponding antigens.
Although the RIA technique is extremely sensitive and extremely specific, requiring specialized equipment, it remains the least expensive method to perform such tests. It requires special precautions and licensing, since radioactive substances are used. Today it has been supplanted by the ELISA method, where the antigen-antibody reaction is measured using colorimetric signals instead of a radioactive signal. However, because of its robustness, consistent results and low price per test, RIA methods are again becoming popular. It is generally simpler to perform than a bioassay.
The RAST test (radioallergosorbent test) is an example of radioimmunoassay. It is used to detect the causative allergen for an allergy.
Elisa
Because the ELISA can be performed to evaluate either the presence of antigen or the presence of antibody in a sample, it is a useful tool for determining serum antibody concentrations (such as with the HIV test[9] or West Nile virus). It has also found applications in the food industry in detecting potential food allergens, such as milk, peanuts, walnuts, almonds, and eggs.[10] ELISA can also be used in toxicology as a rapid presumptive screen for certain classes of drugs.
Enzyme-linked immunosorbent assay (ELISA) is a test that uses antibodies and color change to identify a substance.
Antigens from the sample are attached to a surface. Then, a further specific antibody is applied over the surface so it can bind to the antigen. This antibody is linked to an enzyme, and, in the final step, a substance containing the enzyme’s substrate is added. The subsequent reaction produces a detectable signal, most commonly a color change in the substrate.
