Histopathology Flashcards
What does a histopathologist do?
Deals with tissues
Examined tissue sections, noting the architecture of a tissue and what it tells us about a particular disease
The information given can be used In diagnosis and to see the efficacy of a treatment
What is a cytopathologist?
Deals with cells
Often take cells from a patient, prepare these, and deliver an expert diagnosis on the cell sample
What tissue samples does a histopathologist deal with?
Biopsies
Resection specimens
Frozen sections
Post-mortems
What is a biopsy?
Small sections of tissue removed from a patient.
Usually placed in formalin which preserves the tissue (by cross linking proteins).
Then are embedded in a paraffin wax to allow very thin sections (2-3 mu m) to be cut using a microtome.
Then mounted on a microscope slide.
Stains such as harmotoxylin and eosin (for blood cells) , and ziehl-neelsen (for detecting TB) can be used
Why are Biopsies normally used?
To make diagnoses
Eg is there a need for surgery
What are resection specimens?
Taken from tissue that has been removed as part of a surgical procedure and are processes for a biopsy.
The tissue sections can also be sent to biobanks for genomic studies of diseases
Why are resection sections normally used?
To look at the stage of a disease (eg cancer)
What are frozen sections?
Taken during surgical procedures and are examined by pathologists in real time while the patient is being operated on.
The great tissue is frozen by a cryostat, cut, them mounted on glass slides and stained
This technique gives rapid results so that information on what needs to be done can be relayed back to the surgeon
How long do results take for biopsies, resection sections and frozen sections?
Biopsies - 2-3 days
Resection sections - 5-7 days
Frozen sections - 30 mins
What are fine needle aspirates?
A fine needle can be stuck into a lesion to suck out (aspirate) the cells so they can be analysed for a smear
This is useful as the fine needle can penetrate some inaccessible tissues.
However the cytopathologis is only looking at cells, and not tissue architecture
Roughly how many tests to pathology labs offer?
86
53 of which are used to detect the levels of specific antibodies circulating in patients had
What is hostochemistry?
Manufactured antibodies can be used to specifically take molecules
Allows histopathology and cytopathology to be used in conjunction
What are conjugations?
Can be attached to antibodies (Fc region (on the constant heavy chain) ) to make them functional in histochemistry
Eg: enzymes, fluorescent probes, magnetic beads (can be used to purify cell types using a magnet), drugs
How can antibodies be used as diagnostic tools?
They are specific to an antigen.
Antibodies are easy to generate and can be used to detect a range of molecules.
They can be used in direct (using a primary antigen only, with a conjugate) and indirect detection (uses more than one antibody, the primary, and a secondary one that has a conjugate)
What are some uses for manufactured antibodies?
Blood group serology (blood type)
Immune assays - detection of hormones or circulating antibodies/antigens to detect presence of a disease
Immunodiagnosis - to detect antibody levels or presence of infectious diseases. Can also be used to detect hypersensitivity reactions
