Cancer, CAD, CHF Flashcards
What are the 6 hallmarks of cancer?
Sustaining proliferative signaling, resisting cell death, inducing angiogenesis, enabling replicative immortality, activating invasion and metastasis, evading growth suppressors
Are telomerase up or down- regulated in cancer?
UPregulated, these are the enzymes that maintain telomeres, which lets the cell keep living
What is p53?
Tumor suppressor gene that prevents damaged cells from proliferating; turned off in cancer cells
Proto-oncogenes vs. oncogenes?
Proto-oncogenes have regular function in the cell relating to proliferation and differentiation
When over-expressed, they can become oncogenes, the cancerous version of this cell
What is the two-hit hypothesis?
Describes why tumor suppressor genes become insufficient to prevent cancer
Both alleles for a tumor suppressor gene must be mutated in order for a gene to lose function (germline and somatic)
How does Methotrexate work?
Methotrexate has a higher affinity for DHFR (dehydrate reductase) compared to FH2, preventing reduction to FH4
Note: A cell needs folate for replication and it is reduced to FH2 then FH4 to produce nucleosides
What is doxorubicin?
Cytotoxic antibiotic that indirectly inhibits topoisomerase II
Top II relaxes DNA coil and breaks the strand for replication
Doxorubicin prevents the DNA strand from being put back together, inhibiting DNA replication
What is cyclophosphamide?
Alkylating agent that prevents replication of DNA by attaching alkyl groups to guanines which causes guanines to crosslink, sticking DNA so it can’t uncoil and can’t replicate
What is vincristine?
Interferes with mitosis by binding to microtubule dimers, preventing polymerization (pulling apart) of dimers, this arrests the cell in metaphase
What is tamoxifen?
Treats estrogen receptor positive breast cancer by antagonizing at the estrogen receptor, preventing cell proliferation
What are monoclonal antibodies 2 functions?
- block growth signals
2. stop new blood vessels from forming
How does Cetuximab work?
Blocks growth signals
Cetuximab binds to mutated growth factor receptor and prevents its downstream signaling (proliferation)
Because Cetuximab only prevents DOWNSTREAM signaling, in what case would it not be effective?
When hyper-proliferation is caused by something other than mutated external growth factor receptor
How does Bevacizumab (Avastin) work?
Anti-angiogenic
Monoclonal antibody that blocks angiogenesis
Inhibits vascular endothelial growth factor A
How do tyrosine kinase inhibitors work? Example: Gleevec (imantinib)
Prevent phosphorylation of the tyrosine kinase target
Tyrosine kinase is an enzyme that removes a phosphate group from ATP and attaches it to a tyrosine amino acid which starts a signaling cascade leading to cell proliferation
What is BCR-Abl?
A fusion gene of the philadelphia chromosome/translocation (chromosome 22 is long, 9 is short, they easily translocate, associated with CML)
It contains a portion that codes for tyrosine kinase. When it is mutated, tyrosine kinase is always on.
At rest, coronary blood flow is ___mL/min/100g which is ___% cardiac output. ___% oxygen extracted from myocardial tissue beds
70mL/min/100g
5% CO
70% oxygen, very high!
With intense exercise, coronary blood flow increases ____ fold (supply) and demand increases ____ fold
Supply by 2-4 fold
Demand by 4-7 fold! This includes preload, HR, contractility
What equation describes perfusion pressure to the LV?
DBP - LVEDP
So someone with diastolic dysfunction has trouble with perfusion! Remember, coronary arteries fill during DIASTOLE
The incidence of myocardial ischemia in surgery is highly related to what?
HIGH HR (over 110)
What increases myocardial oxygen supply? What increases demand?
Supply: hemoglobin conc, O2 sats, bradycardia, inc DBP, low preload, dec contractility
Demand: tachycardia, high afterload, high preload, inc contractility
What is the HR goal with CAD patient? What meds are used, what is contraindicated/cautioned?
Slow
B-blockers, Ca channel blockers used
Caution with isoproterenol, dobutamine, ketamine, pancuronium
What is the preload goal with CAD patient? What meds are used, what is CI/cautioned?
Low-normal
Nitroglycerine, diuretics used
Caution with volume overload
What is the afterload goal with CAD patient? What meds are used, what is CI/cautioned?
High-normal
Phenylephrine used
Caution with nitroprusside and high-dose volatile agents