What safety precautions should be taken into account when handling tiss. w/ mirco-o?
- fixed w/ Neutral buffered formalin (except for prion misfolded protein- Mad cows disease- fixed w/ hot formic acid before NB formalin)
- PPE: coat, gloves, glasses
- Universal precautions
How are micro-o detected & identified?
- detected by: special stains, testing, microscope, electron microscopy
- Identified by: non-specific inflammation/ typical tissue rxn (e.g. neutrophil, leukocytes @ site); or ID appearance
List the cells of inflammation & their appearance
- neutrophil (PMN): purple multi-nuclei w/ pink granules (1st)
- Eosinophil: purple bi-lobed nuclei w/ red granules (2nd)
- Basophil (mast cell): purple bi-lobed nuclei w/ lots of purple-blue granules
- Macrophages: irregular border w/ purple kidney-shape nucleus
- Lymphocytes (B & T): large purple nuclei w/ lil cytoplasm
What’re the histological features of chronic inflammation
- Exudation: pus formation & destruction
- Macrophage accumulation: remove debris & release attractants for T & B cells
- Repair: proliferation of fibroblast, collagen, lymphocytes & plasma cells
scarring - lymphocyte accumulation due to cell or humoral mediated response
List e.g. of pathogens
- Virus
- Bacteria
- Fungi
- Protozoa
- Helminths
What’s the size range of virus, chlamydia, rickettsia?
Virus: 20-30nm
Chlamydia: 125-300nm
Rickettsia: 300-1200nm
What’s the size range of bacteria, protozoa, fungi?
Bacteria:1-14um
Protozoa: 1-50um
Fungi: 2-200um
What’s the size range of metzoans?
3-10mm
List important bacteria in lecture (6)
- S. aureus
- H. pylori
- Bartonella henselae
- Neisseria sp.
- M. Tb, M. laprae, MAIC
- Klebsiella
List important fungi in lecture (5)
- Tricophytan
- Aspergillus israelli
- Candida albicans
- Cryptococcus neoformans
- Pneumocystis jurovecii (carinii)
List important protozoa in lecture (4)
- Entamoeba histolytica, E. gingivalis
- Giardia lambia
- Trichomanas vaginalis
List important worm in lecture (3)
- Enterobus vermicularis (pin worm)
- Trichuris trichuria
- Echinococcus granulosus
What’s the factors contributing to infection (& the reason)? (5)
- Increase mobility (from tourism, immigration)
- Immunodeficiency states (from HIV/AIDS)
- Antibiotic resistant micro-o (from MRSA, VRSA, Tb)
- Adaptive mutation (from SARs, H7N9)
- Bioterrorism (small pox, botulism)
What are the reasons to identify infectious agents? (4)
- Diagnosis
- Identify failure in vaccination programmes
- Epidemiological data
- Adjust public health policy
What are the outcomes for acute inflammation?
- Resolution
- Tissue destruction & suppuration
- Healing w/ or w/out fibrosis
- Chronic inflammation
- Septicaemia/death
What’s fibrous pericarditis & which inflammatory cell is involved?
Deposits of fibrin in percardium (fibrous exudate). Neutrophil involved
What’s suppurative inflammation & which inflammatory cell is involved?
A pocket/collection of pus due to bacteria. Neutrophil involved
What factor influences the progression & duration of acute inflammation?
- presence of foreign bodies
- Hypersensitivity
- lowered host resistance
- delay in healing
What factor influences the progression & duration of chronic inflammation?
Destruction & inflammation still occurring while site is trying to heal
What macroscopic clues are there?
- Pus,
- Necrosis
- Cavitation
- Pseudomembranous exudate
What microscopic clues are there?
- Granuloma
- Charcot-Leydin crystals
- Cytopathic effect: structural changes in cell due to viral infection
What’s the gold standard detection method?
culturing microbes
What are some features you would expect to see in a tiss. w/ acute or chronic inflammation?
- Acute: Neutrophils, pus, polymorphs.
- Chronic: Macrophages, lymphocytes, giant cells
