Part 1: Introduction and Cell Components

Question 1

how does electron microscopy work

Answer 1

it uses a beam of accelerated electrons as a source of illumination

Question 2

what type of electron microscope creates 3-D but may require special preparation of the sample

Answer 2

scanning electron microscope

Question 3

what type of electron microscope offers the greatest magnification, high resolution in two dimensions, and uses a fluorescent screen

Answer 3

transmission electron microscope

Question 4

what is the relationship between speed of an electron and wavelength of an electron

Answer 4

there is a direct correlation

Question 5

what is the % of formaldehyde in aqeuous buffered formalin

Answer 5

37%

Question 6

what is the pH of formalin

Answer 6

7.0 - neutral

Question 7

what are four examples of formed elements seen in tissue after fixation

Answer 7

nucleoproteins
intracellular cytoskeletal proteins
extracellular proteins
membrane phospholipid-protein or carb complexes

Question 8

what substance clears tissue of alcohol before it is imbedded into paraffin

Answer 8

xylene

Question 9

how thick are usual histologic sections

Answer 9

typically 4 microns

Question 10

what is the common mounting media used to coverslip tissue

Answer 10

paramount

Question 11

what is the first stain used in the staining process

Answer 11

hematoxylin

Question 12

what counter stain is used in the staining process

Answer 12

eosin

Question 13

what salt additive is used as a mordant to make hematoxylin act as a basic dye

Answer 13

aluminum

Question 14

eosin attaches to what charged components in a cell

Answer 14

catatonic, + charged

Question 15

what is a heavy metal that can be used to bind with lipids in the tissue commonly used in EM

Answer 15

osmium tetroxide

Question 16

what is a good preservative to use when submitted tissue for EM

Answer 16

glutaraldehyde

Question 17

what is a common transport media for live cells, especially lymph nodes

Answer 17

RPMI

Question 18

what temperature is used for a cryostat

Answer 18

-15 to -20 degrees celsius

Question 19

what methods of snap freezing causes the least amount of damage

Answer 19

isopentane

Question 20

what is the most common method of snap freezing

Answer 20

liquid nitrogen (-196 degrees celsius)

Question 21

what staining technique may be used to identify lipids during a frozen section

Answer 21

thionine

Question 22

what stain is used for a parathyroid frozen

Answer 22

oil red-o

Question 23

what is the name of the part of the antibody that binds to the antigen in IHC

Answer 23

epitope

Question 24

what are the common reagents used for blocking in IHC

Answer 24

3% of both peroxidase and serum albumin

Question 25

what are the three methods of labeling antibodies in IHC

Answer 25

flurochromes enzymes EM

Question 26

cytokeratin identifies what

Answer 26

carcinoma and adenocarcinoma

Question 27

vimentin identifies what

Answer 27

CT tumors and melanoma

Question 28

LCA identifies what

Answer 28

leukemia and lymphoma

Question 29

CD20 identifies what

Answer 29

B lymphocytes

Question 30

CD3 identifies what

Answer 30

T lymphocytes

Question 31

CD34 identifies what

Answer 31

angiomas, angiosarcoma, and fibroblastic tumors

Question 32

SMA identifes what

Answer 32

myofibroblastic and myoepithelial tumors

Question 33

desmin identifies what

Answer 33

muscle

Question 34

S-100 identifies what

Answer 34

neutral cells, cartilage, granular cell tumors, and melanomas

Question 35

HMB-45 identifes what

Answer 35

some melanomas

Question 36

what is the name for the study of tissue structure

Answer 36

microanatomy

Question 37

what are the 5 ways electrons react to an object in electron microscopy

Answer 37

unscattered (go right through) secondary electrons auger electrons form an x-ray back scattered

Question 38

what are some disadvantages of electron microscopy

Answer 38

expensive large machine sensitive to things like vibrations specimen must be in a vacuum chamber needs a constant voltage supply needs circulation of cool water needs personnel training

Question 39

what are some advantages of anatomic force microscope (a type better than electron microscopy)

Answer 39

sample preperation is easier works in a vacuum, air, and in liquids living systems can be studied, no fixation needed higher resolution then TEM

Question 40

what are some disadvantages of anatomic force microscope

Answer 40

limited vertical range limited magnification range tip or sample can be damaged

Question 41

why is super resolution microscopy so affective

Answer 41

allows for visualization of subcellular organization with lots of details

Question 42

what are the three main steps associated with routine tissue preparation

Answer 42

formalin fixation paraffin embedding and cutting staining

Question 43

what properties does formalin fixation provide

Answer 43

terminate cell metabolism prevent enzymatic degradation of cells by autolysis kills pathogens hardens tissue maintains general structure of cell

Question 44

what process must occur to tissue on a slide before it can be stained

Answer 44

dissolve paraffin with xylene rehydrate tissue using decreasing alcohols

Question 45

how is water removed after washing the formalin from the tissue

Answer 45

using a series of dehydrating alcohol

Question 46

why must the tissue go through a series of alcohols before staining with eosin

Answer 46

eosin is more soluble in alcohol than water

Question 47

which stain will show nuclear DNA and cytoplasmic RNA more

Answer 47

hematoxylin

Question 48

hematoxylin attaches to what charged components in a cell

Answer 48

anionic, - charged

Question 49

what is an example of a negatively charged component (basophilic) in a cell

Answer 49

nucleus

Question 50

what is an example of positively charged component (acidophilic) in a cell

Answer 50

proteins in the cytoplasm

Question 51

what does basophilic mean in tissue staining

Answer 51

tissue readily stains with basic dyes such as hematoxylin

Question 52

what does acidophilic mean in tissue staining

Answer 52

tissue readily stains with acid dyes such as eosin

Question 53

what is a good preservative when submitting skin for immunofluorescence

Answer 53

Zeus (Michele's media)

Question 54

why would you do frozen section on tissue

Answer 54

no preoperative diagnosis unexpected intraoperative finding evaluation of surgical margins

Question 55

what media is used in performing a frozen section

Answer 55

OCT (optimum cutting temperature)

Question 56

what are the three steps to prepare a frozen section

Answer 56

freeze tissue in OCT cut tissue in cryostat stain tissue on a slide and cover slip

Question 57

immunohistochemistry targets antigens within the tissue by applying what substance

Answer 57

antibodies tagged with visual markers

Question 58

what are some uses of immunohistochemistry

Answer 58

identify replicating cells, signaling cells, apoptotic cells, activation states, and different types of cells within the same tissue

Question 59

what are the benefits of formalin fixation in IHC

Answer 59

antibodies preform optimally prevents degradation of tissue preserves position of antigen

Question 60

what is the advantage of freezing tissue in liquid nitrogen or isopentane for IHC

Answer 60

the antigen is preserved

Question 61

what is the disadvantage of freezing tissue in liquid nitrogen or isopentane for IHC

Answer 61

freezing artifact alters cellular morphology

Question 62

what are two methods of antigen retrieval for IHC

Answer 62

HIER (heat inducted epitope retrieval) enzyme digestion

Question 63

what is the main purpose of the antigen retrieval process in IHC

Answer 63

to increase the accessibility of the antibody to the antigen

Question 64

what is the purpose of permeabilization in IHC

Answer 64

to improve antibody penetration to access nuclear and cytoplasmic antigens

Question 65

what is the purpose of blocking in IHC

Answer 65

to eliminate background staining

Question 66

what are some disadvantages of using direct IHC techniques

Answer 66

less signal amplification so may not get a signal with little antigen conjugation process may interfere with the antibody to react with target antigen

Question 67

what is the main advantage of indirect IHC

Answer 67

sensitivity of antibody reacting to the target antigen is increased because multiple secondary antibodies can bind to a single primary antibody amplifying the signal

Question 68

what are the main differences between monoclonal and polyclonal antibodies used in IHC testing

Answer 68

monoclonal are consistent from batch to batch but may have false negative results polyclonal tend to have non-specific reactivity and vary from batch to batch

Question 69

how are the results of IHC testing validated

Answer 69

using known positive and negative controls

Question 70

what are some advantages of enzymatic methods of IHC

Answer 70

they can be viewed through a standard light microscope enzyme table specimens have an unlimited shelf life

Question 71

what are some disadvantages of enzymatic methods as compared to fluorescent methods in IHC

Answer 71

fluorescence has better resolution enzyme intubation process causes testing to take longer enzyme amplification interferes with signal quantization substrates used to activate enzymes can be toxic or carcinogenic

Question 72

positive controls are useful in IHC in detecting false negatives caused by what

Answer 72

poor fixation of tissue problem with tissue processing

Question 73

what are negative controls in IHC useful in detecting

Answer 73

endogenous biotin peroxidase activity

Question 74

what information does IHC provide a Pathologist

Answer 74

rendering a diagnosis when morphology alone isn't enough differentiation of a tumor often used as prognosis and predictive markers in therapeutic treatment

Question 75

what microbiology technique is preformed on cultured cells or embryos to localize specific nuclear sequences as small as 10-20 copies of mRNA or DNA

Answer 75

in situ hybridization

Question 76

what microbiology technique is used to detect minute quantities of rare or single copy number nucleic acids sequences in frozen or embedded cells or tissue sections for the localization of those sequences within the cells

Answer 76

PCR

Question 77

what is a single-stranded nucleic acid employed in the hybridization, requiring a color molecule to attach to it

Answer 77

a probe

Question 78

what is used in the amplification of a sample in a hybridization technique that is significantly shorter than a probe

Answer 78

a primer

Question 79

what type of test is used to determine trace amount of DNA in a sample

Answer 79

PCR

Question 80

what type of test is appropriate for determining if there are antibodies present in the blood as a result of exposure

Answer 80

serology testing