Chem 6B Special Chemistry

Front 1

What is a monoclonal spike?

Back 1

Monoclonal spike: represents antibodies arising from one population of cloned plasma cells, or one class of immunoglobulins from a disease process.

Front 2

What would a greatly elevated CKMB tell you? What is teh purpose of calculating an index?

Back 2

Injury to cardiac muscle. The index tells us the % of CK-MB in the total CK and can help elucidate the source of teh CKMB.

Front 3

What is the specimen of choice for lactic acid? Whan is an elevated lactic acid seen? What are the side effects of a greatly elevated lactic acid?

Back 3

Lactic acid.
Plasma (anticoagulated whole blood) in NaF or K oxalate tubes; cool immediately. Increased lactate is seen in conditions causing increased anaerobic glycolysis like shock, strenuous exercise, pulmonary edema, severe anemia & ethanol intoxication

Front 4

Illustrate the principle of RIA & discuss the regulations to be met.

Back 4

RIA (radioimmunoassay).
Antibodies attached to a solid phase are exposed to both unlabeled patient antigens & purchased radioactively-labeled antigens. The 2 antigens compete for binding sites on the stationary antibody. Unbound antigens are removed & the bound labeled antigen is measured. The concentration of patient antigen is inversely proportional to the amount of labeled antigen.

Front 5

List tests done with RIA technology.

Back 5

RIA tests:

Serum B2 & folate

Front 6

Name several clinical uses of the quantitative beta-HCG.

Back 6

beta-HCG uses:
Pregnancy determination; ectopic pregnancies have consistently low HCG;
Hydatidiform moles, choriocarcinoma, seminoma, & other cancerous conditions

Front 7

What happens when a person is deficient in B12 or folic acid?

Back 7

Deficient B12 or folic acid.

Megaloblastic anemia;
Imparied & alteration in protein synthesis;
Neurologic problems occur with B12 deficiency.

Front 8

What time of day are cortisol levels highest? Lowest? List several functions of cortisol.

Back 8

Cortisol:
Highest: 6--8 AM
Lowest: 6 PM--12 AM
Stiulates gluconeogenesis & glucogenesis in liver;
Increases calcium absorption;
Stimulates lipolysis in adipose tissue;
Anti-inflammatory activity
Immunosuppressive

Front 9

Name 3 ways radioactivity is released.

Back 9

Radioactivity released:

Alpha particles
Positive or negative charged electrons
Gamma rays

Front 10

What does it mean if a substance is radioactive?

Back 10

It emits electromagnetic radiation as a result of nuclear disintegration.

Front 11

Define half-life.

Back 11

Half-life: the time for sample (radioactive) activity to decrease to 1/2 of its initial value.

Front 12

Define scintillation.

Back 12

Scintillation: brief flash of light given off when gamma rays are absorbed by the sodium iodide crystal in a gamma counter.

Front 13

Define pharmacodynamics.

Back 13

Pharmacodynamics: the study of how a drug acts on a living organism, including the pharmacological response observed relative to the concentration of the drug at an active site in the organism.

Front 14

Define isotope.

Back 14

Isotope: different forms of the same element. Same # of protons & atomic #, but different # of neutrons & atomic weights.

Front 15

Define Curi (Ci).

Back 15

Curi (Ci): unit of radioactivity used before adoption of the Bq as the SI unit.
Ci = 3.70 x 10*10 dsp (disintegration per second)

Front 16

What is the principle of competitive binding?

Back 16

Competitive binding principle:
Enzyme or radioactively labeled antigens compete with the patient's antigens for binding sites on stationary antibodies. Excess labeled antigen is then washed off & enzymatic or radioactivity is measured.

Front 17

Name at least 4 disadvantages of RIA & 2 advantages.

Back 17

Disadvantages RIA:
Radioactive waste disposal is difficult/expensive;
Radioisotope labels have short shelf life (1-2 mo);
Expensive;
Requires license;
Dangerous (exposure to isotopes)
Advantages RIA:
Sensitive;
Easy to automate procedures

Front 18

Illustrate the difference in normal & MI migration of bands on CPK electrophoresis.

Back 18

CPK electrophoresis:
Normal: MB low; MM elevated (cathode)
MI: MB elevated (3/4 of MM)

Front 19

Illustrate normal & MI migration on LDH electrophoresis.

Back 19

Normal/MI--LDH electrophoresis:
LD "flip" betweeen 1 & 2
Normal: 1 low; 2 elevated (anode)
MI: 1 elevated; 2 decreased (about 1/2 of 1)

Front 20

Why is a TRH stimulation test done & what is measured?

Back 20

TRH: thyrotropin-releasing hormone;
Done to improve diagnostic accuracy in patients with symptoms that suggest hypothyroidism, but who have normal results of basal thyroid function tests. It measures pituitary TSH stores.

Front 21

Why is an ACTH stimulation test done & what is measured?

Back 21

ACTH (Adrenocorticotropic hormone):
Done if acute or chronic adrenal insufficiency is suspected & to distinguish between primary & secondary diseases. It measures the ability of adrenal cortex to produce cortisol.

Front 22

In both CK & LD isoenzyme procedure, what is the end product that is measured?

Back 22

CK & LD measurement:
NADH

Front 23

Illustrate the basic protein electrophoresis.

Back 23

Basic protein electrophoresis.
Albumin - a-1 - a-2 - beta - gamma
Anode Cathode

Front 24

Describe teh "sandwich" enzyme immunoassay & the direct enzyme immunoassay.

Back 24

"Sandwich" enzyme/direct immunoassay.
Sandwich: Enzyme labeled antibody conjugated to the antigen-antibody complex is measured.
Direct: Enzyme conjugated to a ligand (usually antigen OR antibody); added to sample; excess enzyme washed off & amount of reaction is measured.

Front 25

Define immunoelectrephoresis.

Back 25

Immunoelectrophoresis: electrophoresis & immunodiffusion combination; used to separate & ID complex proteins.

Front 26

What is diffusing through the agar in immunoelectrophoresis?

Back 26

Immunoelectrophoresis agar diffusion.
Antiserum (in a trough parallel to migration path of the proteins) to 1 or more of the diffused proteins.

Front 27

Discuss the functions of T3/T4 & the ratio of the two.

Back 27

T3/T4.
T4 (thyroxine) & T3 (triiodothymine) secreted by the thyroid gland.
Thyroid hormones' primary function is controlling energy expenditure. Other functions include growth, development & sexual maturation.
T3-free = 80-180 ng/dL
T4 = 5-10 ug/dL
There is 60 more t$ than T3 in circulation, but T3 is 4-5x more metabolically important.

Front 28

Discuss fluorescence polarization competitive binding immunoassay. What happens if a patient has a low or high concentration of antigen?

Back 28

Fluorescence polarization competitive binding immunoassay.
Antibodies specific to the substance being measured are placed on a filter. Add patient antigen. Add enzyme-labeled antigens which fill up the remaining binding sites. Wash with a substrate containing the enzyme substrate to wash the excess antigen & remove excess enzyme. The reaction rate is then measured using fluorescence polarization.

Front 29

When is a MB band seen on a CPK isoenzyme electrophoresis?

Back 29

MB band on CPK isoenzyme electrophoresis.

In myocardial damage

Front 30

What is the purpose of a buffer? Can it be reused? Why or why not?

Back 30

Buffer.
Buffers maintain a steady pH.
Large volumes of buffer (200 mL--1 L) may be reused if the polarity of the electrophoretic cell is switched after each run.
Small volumes of buffer should be discarded after each use.

Front 31

List 3 characteristics of a buffer which affects electrophoretic migration.

Back 31

3 characteristics of buffer.

Ionic strength
Concentration
pH

Front 32

List 7 compounds that are commonly separated by electrophoresis.

Back 32

7 compounds separated by electrophoresis:
Serum proteins, lipoproteins, glycoproteins, urine proteins, nucleic acids, isoenzymes (CK, LD, ALP), hemoglobins, immunoglobulins.

Front 33

Discuss thyroid hormone.

Back 33

Thyroid hormone.
Primary function is controlling energy expenditure. Other functions include growth, development & sexual maturation.