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Cellular Pathology CA 1 > CELL PATH 1 > Flashcards

CELL PATH 1 Flashcards

1
Q

time frame for when results are issued depend on?

A

distance needed to travel and workload

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2
Q

what happens in the gross room include workflow

A

specimens are analysed and reviewed -> specimen is received + logged into computer, gross description is made and dissection occurs if necessary- specimens then go to tissue processing

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3
Q

How do labs identify samples

A

samples are logged into the system, a bar code is given, the date and time received is labelled and if more than one sample is received from a patient numerical designation occurs[ A, B, C]

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4
Q

what is the minimal acceptance criteria for a sample

A

full name
other identifier [DOB or hospital number]
Details about the sample type is it a skin or bone
specimen request form must match specimen pot

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5
Q

comment on the importance of clinical details and give examples

A

accurate and complete clinical details provide a rounded picture of the case- clinical history also helps in diagnosis - i.e. if their was a history with a previous cancer and a liver biopsy is being examined metastatic cancer is a probable diagnosis and immunocytochemistry will be performed. or if there was a history with alcoholism - a liver cirrhosis is a likely diagnosis - special stains would be required

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6
Q

Dissection Area Characteristics

A
  • Must be clean organized + ventilated
    • Adjustable dissecting tables [inbuilt downdraught extraction - allows extraction of toxic formalin fumes
    • Spillage kit
    • Cutting board, ruler, scalper, forceps, handled knife and probes, blunt end scissors, balance, digital recording and photography, PPE [aprons], systems for cleaning
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7
Q

Preparation to dissect

A
  • Review cases that need dissection
    • Assign priority cases
    • Assess case complexity
    • Assess if specimen needs opening
    • Adequate formalin levels
    • Label cassettes [tissue type]
    • Decide specimen type and categories
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8
Q

inking defines?

A

margins of resection # where tissue was cut out [indian ink]differential inking can also be done

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9
Q

Specimen Categories [comment on SOPS]

A

Specimens in A = transfer to tissue cassette =bone cores
B = transfer but need sampling, weighing or slicing =abscess
C - dissection + sampling [diagnostic assessment with preparation] [anus]
D - dissection + sampling [adrenal glands]
E- complex dissection + sampling [thymus]

- SOPS in place for dissection of particular specimen type + clinical history is taken into account
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10
Q

Definition of gross descriptions + what does it include

A

anatomic description which portrays macroscopic appearance of the specimen
1. Type + number biopsies received
2. Dimensions
3. Colour + consistency [tan yellow white]
4. Blood clots / foreign materials [soft hard / rubbery]
5. If Whole or part - assessed?
6. Tumour / abnormalities - location, number and gross description of tumour]

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11
Q

types of biopsy list them

A

Aspiration B -breast biopsy
Core biopsy - a type of percutaneous Biopsy - spring loaded gun = used
Cone Biopsy - diagnose cervical cancer
Endoscopic biopsy - Endoscope = used with sampling instruments
Punch Biopsy - skin rashes

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12
Q

LEEP

A

loop electrosurgical excision procedure

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13
Q

comment on paediatric specimens

A
  • Take special care [difficulties diagnosing]
    • Tumours from child usually small [need specialised procedures s- immunohistochemistry, flow cytometry, cytogenetics, electron microscopy and molecular genetics
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14
Q

give examples of gross-only examination samples

A
  • Some samples = examined only grossly - non-tissue samples
    • Bullets, implants and foreign bodies
    • Tissues - teeth, ribs, fat vessels
    • Foetal samples - miscarriages + still birth - strict guidelines
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15
Q

how long are histology samples stored post-final report

A

30 days

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16
Q

how long are fixed liquid cytology stored

A

21 days

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17
Q

definition of cellular pathology

A

alterations in cells + tissues caused by disease - can be infectious [i.e. helicobacter pylori can withstand stomachs acidic pH]

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18
Q

alterations in tissues can include

A

number, size + distribution of cells and molecular alterations [carbs, lipids, proteins + nucleic acids]

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19
Q

characteristic of cancer cells

A

MAPN
Metastasis - move from initial area of infection + replicate more
Apoptosis - cell death
Proliferate - increase in size
Neoplasia - excessive growth which leads to cancer

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20
Q

distinguish between histopathology + histology

A

histology - study of tissues [microscopic]
histopathology- study of changes in tissues caused by disease [microscopic]

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21
Q

what is clinical cytology// cytopathology

A

study of tissues within fluid

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22
Q

history of pathology - links by to

A

middle east during Islamic golden age
western Europe during Italian renaissance

23
Q

What did the physician Avenzoar do

A

performed the first post-mortem

24
Q

rudolf virchow is?

A

father of microscopy

25
Q

what is formalin

A

A fixative + preservative

26
Q

what are 3 sources of specimens

A

post-mortems, clinics, theatres

27
Q

clinical cytology is involved in the preparation of what

A

fluid smears + fine needle aspirates

28
Q

clinical cytology is used in what screening

A

cancer screening programmes

29
Q

Tissue sample types - SLOBE

A

Scrappings - prostate
Lobe- lung
Organ - kidney
B- biopsies -kidney
E- excision- segment of the colon

30
Q

Analysis of cells + tissue steps

A
  1. Prep for microscopy
    1. Histochemical methods are applied [#stains]
    2. Immunophenotyping of cells [ antibody detects antigen expression]
    3. Molecular analytical methods [changes in gene sequence #allows for early diagnosis]
    4. QC + microscopy + maintain chemical + sample materials
31
Q

what happens if tissue is not preserved

A

autolysis + putrefaction can occur immediately

32
Q

Types of tissue preservation

A
  1. Chemical preservation [most common] fixation in 1. formaldehyde 2. Glutaraldehyde or alcohol
    1. Freezing - snap freeze + store in freezer
    2. Heating - microwave preservation - Thermal [heating - protein coagulates which are abundant so tissue is held in place - boiling or microwave]
      - Freezing - water crystalizes solid matrix is formed and tissue is hard - CO2 and liquid nitrogen
      Chemical types of fixatives [most widely used] - done by coagulation + cross-linking - tissue samples are placed in chemical solutions which must permeate tissue [smaller specimens are permeated quicker + smaller]
33
Q

Histochemistry
+ 4 e.g.s

A

study of chemical interactions in visualizing cell and tissue components 1. Dye stains
2. Metals [Gold + Silver staining]
3. Immunocytochemistry [antibody attaches label [binds to antigen] then allows visualization
4. DNA or RNA probe attaches label to nucleic acid - visualization

34
Q

FIXATION definition

A

use of physical and chemical methods to prevent changes associated with tissue decay

35
Q

Most tissues can be fixed but some can’t

A
  1. Muscle biopsies for enzyme histochemistry
    1. Skin + mucosal biopsies to investigate inflammatory skin conditions
      [poor fixed tissues can compromise diagnosis [ will be visible once stained]
36
Q

2 main reasons for fixation

A

prevents autolysis/putrefaction + maintains morphology + contents of tissue

37
Q

what changes occur naturally to the nucleus

A
  1. KARYOLYSIS - nuclear fading chromosomes become denatured by DNAase and RNAase
    1. Pyknosis - DNA condenses - ends up as shrunken basophilic mass
    2. Karyorrhexis - pyknotic nuclei membrane ruptures and undergoes fragmentation
      ALL of above lead to nucleus being dissolved and eventually leads to a dead cell with no nucleus
38
Q

Ideal fixatives should do? give 6 examples

A
  1. Prevent autolysis + bacterial decomp
    1. Keep tissue in natural state + components
    2. Make tissue insoluble in liquids that’ll be used later in tissue processing
    3. Preserve tissue volume so it doesn’t swell
    4. Avoid excessive hardness
    5. Non-toxic + no-carcinogenic
39
Q

give examples of cross-linking fixative + how does this cross-link form

A

Formaldehyde + glutaraldehyde - methylene bridge is formed between side and end groups of proteins

40
Q

Mechanism of formalin

A
  • Protein fixative
    • Formed when formaldehyde [colourless gas] is mixed with H2O
    • Is a liquid
    • 10% formalin = 4% formaldehyde
    • Commonly used in fixation
    • Formaldehyde + H2O = made of methylene glycerol which is added to a protein and H2O is removed = METHYLENE BRIDGES = FORMED between 2 proteins bound due to m. glycerol and [protein reaction]
41
Q

Benefits of formalin

A
  • Cheap slow permeation
    • Quick for small samples larger specimens= done overnight
42
Q

disadvantages of formalin

A
  • Biohazard
    • Effects other biomolecule cells - Cytoplasmic streaming - carbs moved to side gives uneven staining [glycogen] - not suitable when testing glycogen storage disease
43
Q

Control measure for Formalin// HEALTH + SAFETY ISSUES

A
  • Toxic + carcinogenic
    • PPE, containment level 2, well ventilation [formalin fumes are extracted when pot is opened]
44
Q

fixation rate is divided into 2 parts

A
  1. Penetration rate [ time taken for chemical to reach innermost surface]
    1. Reaction rate [time taken for whole specimen to be fixated
      FIXATION RATE - 0.75mm per hour = 8 hours for total specimen
45
Q

Glutaraldehyde

A
  • CHO.(CH2)3.CHO
    • Best morphological preservation
    • Also cross-linking preservative
    • Used in 2.5% ph Buffer
    • Used for specimens undergoing electron microscopy [ not as effective permeation - so can’t be used on big specimens]
46
Q

Comment on coagulant fixatives

A
  • Alternative to cross-linking fixatives
    • Dehydrate tissues [pull water out]
    • Increased penetration rate
    • Cause shrinkage [ poor preservation of mitochondria - not suitable for investigating disorders of mitochondria
      E.G. ethanol, methanol, acetic acid and acetone
47
Q

other fixatives names DPMO-C

A
    • Osmium tetroxide - oxidising agent, secondary fixative - turns black [fixes lipid]
    • Mercuric chloride - precipitates proteins - good staining quality - hardens tissue
    • Picric acid - used in fixative solutions - changes charges of proteins side chain - good glycogen fixative
    • Dichromate fixatives - secondary fixative - K dicromate = used to show chromaffin reaction [oxidation catecholamines synthesized by tumours - adrenal gland
      Compound fixatives
48
Q

Problems of fixation

A
  1. Under fixation
    1. Over-fixation
    2. Antigen masking [ foreign ag = no longer accessible for histochemistry
    3. fixated related deposits
49
Q

List factors that affect fixation

A
  1. Buffer + ph [in low ph target groups on proteins = unreactive in formaldehyde] + the cross-linking effects of formaldehyde = reduced
    1. Duration of fixation + specimen size - time=distance fixative needs to penetrate through, compound fixatives components fixate @ diff rates. Gross specimens shouldn’t be allowed to sit in fixative rather suspended
    2. Temperature [ molecules diffuse quicker at an increased temp i.e formaldehyde penetration increases @ higher temp - tissue processors = enclosed @ higher temps 60-65 [but its controlled due to danger of fumes]
    3. Concentration of fixative -need to get it right as it varies from fixative -> fixative if formalin conc is greater than 10% = 10% hardening + shrinkage [ineffective fixation] + ethanol concen less than 70% will fail to remove water
    4. Osmolarity of fixative [best results when slightly hypertonic [ higher solute concentration] - if hypot-tissue will shrink -too hyper- tissue will swell
50
Q

DECALCIFICATION

A

calcium must be removed from bone samples after fixation

51
Q

what is decalcification

A

the removal of calcium from bone samples after fixation

52
Q

Tissues is fixed [list following steps in x4

A
  1. Tissue processing
    1. Microtomy [cutting + paraffin wax]
    2. Staining
    3. Microscopy
53
Q

what is tissue processing + give overview

A

removal of H2O- which is replaced with a medium - tissue is solidified and can be cut by microtome [done by tissue processor
1. Dehydration - H2O + fixative = removed
2. Clearing - dehydrating fluids = removed - tissue can now receive infiltration medium
3. Infiltrating - tissue is permeated with a support medium [paraffin wax]
4. Embedding - tissue = orientated in medium -> solidifies

54
Q

aims of tissue processing

A
  • Medium used = stable, firm, non-hazardous [i.e. wax]
    • Helps ability to cut thin section
    • Allows good preservation of tissue morphology + their contents
    • Long term preservation

Cellular Pathology CA 1 (1 decks)

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