midterms Flashcards
The following can gross specimens
histotechnologist
biomedical scientists
resident
pathologist
physician assistant
Cellular materials are spread
lightly (slide, applicator stick, or
wire loop)
smear preparation
optimum condition of tissue for sectioning in cold knife procedure
0 to 10c
Utilized when rapid diagnosis of tissue is required
FROZEN SECTIONS
other word for cryostat procedure
cold microtome
example of additive fixation
formalin
mercury
osmium tetroxide
T or F? Fixative have the property of forming cross links between proteins
True
proteins and cells are digested and broken down by their own enzymes, independent of a bacterial action, this process is known as
autolysis
a portion of the tumor is removed
incisional biopsy
Acts as both fixative and dehydrating agent
ALCOHOLIC FIXATIVES
Tissues should not be more than
5mm thick
types of fixatives according to composition
simple (one component)
compound (2 or more)
Important determinants of neoplastic specimens
tumor
Fixes nucleoproteins, chromosomes and destroys the
mitochondria and Golgi bodies
GLACIAL ACETIC ACID
Practical consideration of fixation speed
fixed immediately
Rapid decomposition occurs in the following organs
kidney
liver
pancreas
T or F? All the controls to the microtome are operated from outside the cabinet
True
Correct fixative to tissue ratio
20:1 to 10:1
Primary purpose of fixation
preserve the morphological and chemical integrity of the cell
Most common metallic fixative, 5-7%
MERCURIC CHLORIDE
Tissues are placed in a
microscopic slide and forcibly
compressed with another slide or coverslip, less than 1mm thickness of tissue
squash preparation
alcoholic formalin
coagulates mucus
in hydrogen ion concentration, satisfactory fixation occurs between
6 to 8 pH, nuclear <4.6 and cytoplasmic >4.6
These studies may require fresh samples, fixed
specimens
pediatric specimens
osmolality required in the fixation of fixatives
hypertonic - shrink
hypotonic - swell
ideal - 400 to 450
three important determinants of neoplastic specimens
overall size of tumor
depth of invasion into or through the tissue walls
involvement of margins and lymph nodes
recommended for CNS tissues
10% formol saline
secondary purpose of fixation
harden and protect the tissue
most rapid and commonly available freezing agent
liquid nitrogen
Achieved by exposing the tissue to chemical compounds called
stabilization
For acid MPS (mucopolysaccharide)/Alcian Blue, Fixes connective tissue mucin
LEAD FIXATIVES
Used for preparing mucoid secretion, vaginal secretion, and gastric content
streaking
May include the year and month the specimen was received
accession number
Usually taken with a larger lesion or of a generalized inflammatory or other disease process
core biopsies
First and most critical step
fixation
microscopic study of tissues affected by disease
histopathology
Incorporated into compound fixatives and Weak decalcifying agent
TRICHLOROACETIC ACID
Tissue specimen is immersed in a
watch glass containing ______________
isotonic normal saline solution
Are processed in cassettes either with a fine
mesh, in lens paper, or in a “tea bag
small specimens
Excellent for glycogen demonstration
PICRATE FIXATIVES
Use a spatula, dissecting needle or applicator stick and streak in a zigzag fashion
streaking
An accurate diagnosis
from this tissue is
dependent upon the
correct
identification
handling
processing
EFFECTS OF FIXATIVES
Hardens soft and friable tissues
Makes cells resistant to damage and distortion
Inhibit bacterial decomposition
Increase optical differentiation of cells
Acts as mordant or accentuator thereby facilitating staining process
Reduce the risk of infection
temperature required in the fixation of fixatives
routine - RT
em - 0c to 4c
considered the primary technique for obtaining
diagnostic full-thickness skin specimens
punch biopsy
Fixative should be __________ the specimen volume
20x
Gross examination and processing of pediatric
biopsies requires special care because
due to diagnostic
difficulties of pediatric lesions/diseases
Should be taken with the lesion at its center
core biopsies
optimum working temperature during cryostat procedure
-18c to -20c
Tissue specimen is immersed in a watch glass containing isotonic normal saline solution
teasing or dissociation
usual fixation time
24hrs
advantage of mercuric chloride
Used for the routine fixative of tissue photography for brilliant metachromatic staining of cells
removes not only cells, but also a small amount of the surrounding tissue
core biopsy
METHODS OF SMEAR PREPARATION
streaking
spreading
pull-apart
touch
The fixative becomes a part of the tissue by formation of cross links or complexes, Stabilizes the tissue proteins
additive fixation
Zenker’s Solution composed of:
Mercuric Chloride (shrinks the tissue)
Glacial HAC (swells the tissue)
Uses carbon dioxide
cryostat procedure
For preparation of direct impression from the cut surface of tissue: lymph nodes, other surgical secretions, autopsy secretions
touch smear
Depending upon the size of the biopsy, it may be bisected, trisected, or cut into sections
shave biopsies of skin
duration of fixation required in the fixation of fixatives
24hrs
preservative and storage of surgical, post-mortem and research specimens
10% neutral buffered formalin
2 METHODS OF PREPARING FROZEN SECTIONS
cold knife procedure
cryostat procedure
Highly explosive when dry, Yellow in color
PICRATE FIXATIVES
Preserve specific parts and particular microscopic elements of the cell
cytological
workflow of histological technique
fixing
processing
embedding
cutting
staining
microscopy
Small core biopsies______________ should be embedded totally without cutting it.
2mm
recommended for routine post-mortem tissues
formol-corrosive
Satisfactory for routine paraffin sections, For electron microscopy, and For Histochemical and enzyme studies
ALDEHYDE FIXATIVES
Practical consideration of fixation penetration
1mm/hr
Frozen Section Indications:
rapid diagnosis
to optimally process tissues for special studies for diagnosis, treatment, or research
to confirm that lesion tissue is present for diagnosis on permanent sections (sample adequacy)
Method of choice for surgical removal of ________________ but
may be sometimes removed by shaving
whole organ, excisional biopsy
mounting media of cryostat
water
20 – 30% Bovine Albumin
Von Apathy gum syrup
optimum condition of tissue for sectioning in cold knife procedure
5c to -10c
T or F? small specimens should NOT be cut, bisected, or inked while fresh and infixed
True
Pediatric tumors are rare — often necessary
to use the ff:
immunohistochemistry
electron microscopy
flow cytometry
cytogenetics
Most common, widely used
FORMALDEHYDE (FORMALIN)
When the entire tumor is removed
excisional biopsy
A refrigerated cabinet in which a modified microtome is housed
cryostat
Process by which the constituents of cells and tissues are fixed in a physical and chemical state so that they will withstand subsequent treatment with various reagents with minimum loss of architecture
fixation
microscopic study of the normal tissues of the body
histology
Fixes brain tissue for rabies diagnosis
ACETONE
Recommended for renal tissue, fibrin, connective tissues and
muscles
MERCURIC CHLORIDE
recommended for preservative of lipids especially phospholipid
formal calcium
freezing agents of cryostat
Liquid Nitrogen
Isopentane cooled by liquid nitrogen
Carbon dioxide gas
Aerosol spray
Other Factors that Affect Fixation
retardation
acceleration
CHARACTERISTICS OF A GOOD FIXATIVE
cheap
stable
safe to handle
hardens tissue
isotonic
Label should be firmly attached to the _________ of container not to the lid of container
body
example of non-additive fixation
alcoholic fixation
Made up of 2 formaldehyde residues linked by 3 carbon chains
GLUTARALDEHYDE
Often small and can be excisional, shave,
core, or re-excisional biopsies
specimen from dermatology
The specimen container label and the accompanying request form should include
patients name
age or birth date
medical record number
microscopy used in teasing or disociation
bright field
contrast
meaning of OCT
optimum cutting temp
Original site of a lesion may need to be re-excised if
the margin are invaded by tumor
too close to the tumor melanoma or basal cell carcinoma
where small fragments of tissue are “shaved” from a
surface (usually skin)
shave biopsy
thickness of section required in the fixation of fixatives
1-2mm² for em
2cm² for light microscopy
microtome of cold knife procedure
cryostat
Decomposition results from
Deprivation of oxygen and essential metabolites
Accumulation of carbon dioxide and other products of cell metabolism
Autolysis
used for serous fluids, concentrated sputum, enzymatic lavage. smears of urinary sediment, vaginal pool, and breast secretion
pull-apart
Permits the general microscopic study without altering the structural and normal intracellular relationship of tissues
microanatomical
METHODS OF FRESH TISSUE EXAMINATION
teasing
squash preparation
smear preparation
frozen section
Used for thick mucoid secretions, smears of fresh sputum, and bronchial aspirates
spreading
optimum condition of knife for sectioning in cold knife procedure
-40c to -60c
disadvantage of mercuric chloride
Considerable lysis of RBC
usual temp for surgical specimen
room temp
methods of tissue examination
fresh tissue examination
preserved/fixed tissue examination
alternative to mercuric chloride formulation
unbuffered zinc formalin
may react with hemoglobin
forming acid formaldehyde hematin
10% FORMALDEHYDE
thickness of frozen section specimens
10-15um
The fixative does not become part of the tissue, Alters the tissue components, Stabilizes the tissue by removing of the bound water
non-additive fixation
is the simplest, least invasive test and uses the smallest needle to simply remove cells from the area of abnormality
fine needle aspiration
Solid structures and tissues must be preserved and carefully processed in the following order
identification
fixing
decalcification
dehydration
clearing
infiltration
embedding
trimming
section cutting
staining
amounting
labelling
cryostat – temp. should be
-17c
Is where tissue specimens
from the operating theaters
and clinics are received
specimen reception laboratory
Preserve chemical constituents of cells and tissues
HISTOCHEMICAL
Deals with the preparation of tissues for microscopic examination
HISTOLOGICAL TECHNIQUE
limitations of frozen section:
Limited section sampling
Ice crystal or freezing artifact
Inferior quality compared to paraffin sections
Lack of special studies
Special stains, immunohistochemistry, culture
Lack of consultation for difficult cases
Method of choice for surgical removal of melanoma but
may be sometimes removed by shaving
excisional biopsy
where tissue is scooped or spooned to remove tissue or
growths from body cavity such as endometrium or cervical canal
curettings
recommended smear preparation for nervous tissue/lipids
frozen sections
Rapidly denatures and precipitates proteins
ALCOHOLIC FIXATIVES
temperature of frozen section
-10c to -20c
Optimal turn-around time of frozen section
less than 15min
Larger core biopsies __________should be bisected eccentrically and embedded
with cut surfaces down
4mm
concentration required in the fixation of fixatives
10%
stock -40%