week 5 Flashcards
clinical manifestations of an allergic reaction:
anaphylaxis
urticaria
angioedema
dermatitis
respiratory allergy
treatment considerations for an allergic reaction:
preparation for anaphylaxis (epi pen)
food diaries
trial avoidance of potential triggers
antihistamines
nasal steroids
allergy shots (immunotherapy)
treatment considerations for an allergic reaction:
preparation for anaphylaxis (epi pen)
food diaries
trial avoidance of potential triggers
antihistamines
nasal steroids
allergy shots (immunotherapy)
describe the appearance of hives:
edematous wheals that blanch with pressure
key treatment for hives:
remove offending agent
types of allergy testing:
RAST serum testing (IgE antibodies)
skin allergy testing
what is angioedema?
a diffuse, non-pitting tense swelling of the dermis and the subcutaneous tissue
what medications are angioedema reactions associated with?
ACE-inhibitors and NSAIDs
what is Celiac disease?
a food insensitivity
an immune reaction to gluten (protein in wheat, barley, and rye)
sx: diarrhea, bloating, gas, fatigue
Tx: remove gluten from diet
what is drug provocation testing?
-administer a medication to a patient in a graduated manner under close observation
-appropriate for patients who are UNLIKELY to be allergic (e.g. “penicillin allergies”)
features common among all signal transduction/intracellular signaling pathways:
- extracellular stimulus (i.e hormone, neurotransmitter, growth factor)
- receptor on cell membrane
- intracellular cell signaling pathway
what are the types of intercellular signals?
autocrine: itself (e.g. T lymphocytes with cytokines)
paracrine: nearby cells (e.g. neuromuscular junction)
endocrine: hormones released into blood stream and stimulates distant locations (e.g. insulin)
juxtacrine: signal binds to neighboring cell receptor, two cells need to be connected (e.g. notch receptor)
basic features of the receptor ligand mediated interactions and signal transduction:
- specificity
- amplification
- modularity
- sensitization and termination
- integration
describe ligand-receptor specificity:
binding of ligand to receptor is mediated by NON-COVALENT interactions
binding brings about a conformational change that alters the activity of the receptor
typically high affinity/specific interaction but the same ligand may bind other isoforms of the receptor or an entirely different receptor with different affinities
how does amplification occur?
enzyme/kinase reactions
what are enzyme/kinase cascades?
- enzymes arranged in a hierarchy in which one enzyme activates many molecules of a second enzyme; amplifications of several orders of magnitude within seconds
- 2nd messengers
what is a second messenger?
intracellular molecule generated in response to extracellular stimuli (1st messenger) that exerts an effect on signaling proteins/enzymes
examples: cAMP, cGMP, phospholipids, calcium
present at low concentration in unstimulated cells, rapidly increase during ligand binding (this increase is TRANSIENT)
describe modularity in terms of ligand binding?
protein receptors = multiple domains that recognize specific binding partners (via domains and motifs)
ensures specific interactions
describe modularity in terms of ligand binding?
protein receptors = multiple domains that recognize specific binding partners (via domains and motifs)
ensures specific interactions
which amino acids do protein kinases phosphorylate?
serine, threonine, and tyrosine
-OH groups
-binding is determined by the AA sequences (domains) surrounding these amino acids
what is the role of phosphatase?
removes phosphate from phosphorylated serine, threonine, or tyrosine
results of phosphorylation:
-alters interactions with other proteins (e.g. act as docking sites)
-oxygen can H bond with the phosphate, these negative charges can repel Asp or Glu, affecting enzyme conformation and activity
-regulation (phosphatase, reverse)
results of phosphorylation:
-alters interactions with other proteins (e.g. act as docking sites)
-oxygen can H bond with the phosphate, these negative charges can repel Asp or Glu, affecting enzyme conformation and activity
-regulation (phosphatase, reverse)
what is receptor desenstization?
receptor signaling is terminated by interacting proteins when the signal is present continuously - uncoupled from the signaling cascade via a protein
receptor down regulated