Prelim Lab #1 Flashcards
Why are there 3 copies needed for Histopath reports
File lab
Physician
Patient
Signatories
Request
Result
Routine Turn-over of results
Surgical Pathology (24 hrs) Frozen section (5-15 mins) Autopsy report (w/in 1 week)
Storage of Specimen
Tissue Blocks (3-10yrs) Slides (indefinitely keep)
Includes entering the details of the specimen in a logbook.
Numbering
Gross description is done by who?
A PATHOLOGIST
Ideal size for specimen processing:
3x2 cm; 3.5 mm thick
In our experiments the size of specimen processing is?
2x2 cm; 4 cm thick
Thickness of the lung specimen
2 cm thick
Preserving the morphology and chemical integrity of the cells as close as to the original as possible.
Fixation
First and most critical step in histotechnology
Fixation
Procedures are adopted to kill, harden and preserve materials for microscopic study
Fixation
Primary goal of fixation?
Preserve
Secondary goal of fixation
To harden and protect the tissue from trauma of further handling
Factors involved in Fixation
Temp Thickness Osmolality pH Concentration Volume Time and Duration of fixation
Inc in Temp
Heat= accelerates process of distortion
The temp is traditionally carried out in a?
Room temperature
Temp. for EM and Histochemistry
0-4 degree C
Temp. for Autotechnicon
40 degree C
It is an automatic tissue processor
Autotechnicon
Formalin used @ 50 degree C
Rapid fixation of urgent biopsies
Formalin used @ 100 degree C
Tissues with TB
Thickness for LM
2 cm2
Thickness for EM
1-2cm2
ph used in fixation
6-8
Why is the pH 6-8 used in fixation?
For satisfactory fixation
The osmolality of fixation must be in what form?
Isotonic
Effect of Hypotonic
Swellin
Effect of Hypertonic
Shrinkage
Concentration used in Fixation
10% Formalin
Ideal time for fixation
20-30 mins.
Why does the ideal time is 20-30 mins?
Because it is followed by interruption of blood supply
Volume for fixation should be
20x the volume of the specimens
Effects of Fixatives
Harden soft and friable tissue
Make cells resistant to damage and distortion
Inhibit bacterial decomposition
Increase optical differentiation of cells
Acts as mordants or accentuations to hasten staining
Reduce the risk of infections
Characteristics of a Good Fixative
Cheap
Stable
Safe to handle
Kill the cell quickly
Inhibit bacterial decomposition and autolysis
Produce minimal shrinkage of tissue
Permit rapid and even penetration of tissues
Harden tissues for cutting
Isotonic
Make cellular components insoluble to hypotonic solutions
Permit the subsequent application of many staining procedures
Gas produce by oxidation of methyl alcohol
Formaldehyde
Best fixative for nerve tissue
Formaldehyde
Powerful reducing agent
Formaldehyde
40% by weight of Formaldehyde
Stock solution; tends to harden
10% solution of formaldehyde
Working solution; forms pigment
What are the pigments formed in 10% solution of formaldehyde
ParaFormaldehyde and formic
Removal of Formalin Pigments
Kardasewitsch’s Method
Lillie’s method
Picric Acid Method
Components of Picric Acid Method
Saturated picric acid
Components of Kardasewitsch’s method
70% ethylalcohol and 28% ammonia h2o
Components of Lillie’s Method
Hydrogen, acetone, peroxide, and 28% ammonia H20
Preserves cellular and plasma protein better
Glutaraldehyde
2.5 % solution of Glutaraldehyde is for?
Small fragment and small needle biopsies fix for 2-4 hrs at room temp.
4% solution of Glutaraldehyde is for?
Large tissue not exceeding than 4 mm thickness and fix at 12-24 hrs at room temp
For thin and ultrathin sections for plastic embedding
Paraformaldehyde
White powder; used as 4% at 4 degree C
Paraformaldehyde
For excellent routine paraffin section
Paraformaldehyde
For CNS tissues
10% formol saline