Other Topics Flashcards
What 3 main factors prevent cellular swelling in UW infused tissue?
- Lack of Na+ or Cl- (therefore no influx possible).
- Presence of extracellular impermeant solutes (lactobionate ions, raffinose).
- Presence of a macromolecular colloid (starch)
What are the other important components of UW solution and what do they help with?
Allopurinol and glutathione acts as an antioxidants, helping to protect the organs from damage from reactive oxygen species (ROS)
What causes oedema in elephantiasis and hydrostatic oedema?
Elephantiasis occurs when parasitic worms block lymphatic vessels and hence fluid accumulates. Hydrostatic oedema is caused by high blood pressure where hydrostatic pressure in vessels pushes fluid out into interstitial space and it accumulates.
What are biopsies?
Biopsies are small section of tissues collected and placed in formalin solution to preserve it by cross-linking proteins. Then embedded in paraffin wax where it is cut into thin slices using a microtome and can be examined under a light microscope. Primarily used to make a diagnoses.
What are resection specimen and why are they used?
Resection specimen are usually taken from tissue removed from a patient during surgery and processed as a biopsy. Primarily used to determine stage of disease.
What are frozen sections?
Taken during surgical procedure and examined in real time. Must be free of any contaminants like formalin.
What does a cytopathologist do?
Aspirates cells which can access relatively inaccessible places without a need for surgery.
What are antibody conjugates?
Attach to Fc region of antibody. Can be enzymes, fluorescent probes, magnetic beads and drugs. Kadcycle is an anti-HER2 antibody which has the cytotoxic drug emtansine attached to it.
What is chymotrypsin and what does it detect?
Is a serine protease composed of three chains A,B and C. Secreted from pancreas and cleaved in duodenum forming active chymotrypsin from chymotrypsinogen. Requirements for recognition by chymotrypsin are an aromatic side chain such as phenylalanine, tyrosine or tryptophan. Carboxyl side of peptide bond is cleaved.
What reaction does chymotrypsin catalyse?
N-Glutaryl-L-phenylalanine p-nitroanilide (GPNA) broken down into N-glutaryl-L-phenyl alanine and bright yellow p-nitroanilide. Has a specificity for molecules with bulky hydrophobic side chains.
What is the Michaelis constant?
Concentration of substrate at which an enzyme works at half its maximal velocity. High Km indicates weak binding on enzyme substrate complex while low Km indicates strong bonding.
What is occuring during inital phase of reaction?
In a steady state as ES complexes formed and consumed at the same rate as long as reaction velocity is maintained.
What is Lineweaver Burk Plot?
1/[S] on x-axis and 1/V0 on y-axis. Slope = Km/Vmax while y-intercept is 1/Vmax and x-intercept is -1/Km.
How is absorbance used to measure progress of reaction?
Find maximum absorbance wavelength for substance and measure at this wavelength. Absorbance will increase with time.
How can competitive drug activity be seen through Lineweaver Burk plots?
For a competitive antagonist, which occupies all or part of the active site of an enzyme, simply adding enough substrate will outcompete the antagonist. The effect is therefore to inhibit KM but have no effect on Vmax.
