Heme/Onc Flashcards
Plummer-Vinson syndrome symptoms
Triad
Fe deficiency anemia
beefy red tongue
esophageal webs
What is methemoglobinemia
when Fe2+ iron oxidized to Fe3+ iron
cause of TTP
- symptoms/signs
- treatment
ADAMTS13 mutation
vWF not cleaved –> traps and activates platelets
Microangiopathic Hemolytic anemia (incr LDH, decr haptoglobin) with schistocytes
Thrombocytopenia
sometimes- renal failure, CNS, fever
plasma exchange
Glucocorticoids
Rituximab
explain one mechanism by which tumor cells can become resistant to chemotherapeutic agents
human multidrug resistance (MDR1) gene
- codes for P-glycoprotein, a transmembrane ATP-depedent efflux pump protein
- reduces drug influx into cytosol and increase efflux from cytosol
(similar mechanism by which many bacteria have developed resistance to abx)
how does methotrexatae work as a chemo agent
folic acid analog that inhibits dihydrofolate reductase
-> inhibits DNA synthesis
causes death of all rapidly dividing cells (esp in GI where can cause ulcers and in bone marrow where can cause pancytopenia)
features of CLL
smudge cells (Crushed Little Lymphocytes) CD5 and CD20 positive B-cells
age >60y
fear transformation to an aggressive lymphoma (most commonly diffuse large B-cell lymphoma)
features of ALL
most freq in children
assoc with Down syndrome
t(12;21) better prognosis, this transloc most common in kids
adults may have t(9;22) philadelphia transloc
TdT+, CD10+ (if it’s the B-cell form)
T cell form presents as mediastinal mass (thymus) and SVC-like syndrome
CD7+
most responsive to chemotherapy
however can mets to CNS and testes (poor chemo penetration) so must radiate/chemo these specially
features of Hairy Cell Leukemia
mature B-cell tumor
hair-like cytoplasm projections
dry tap on aspiraiton (causes marrow fibrosis)
present with massive splenomegaly (WBC fills red pulp)
stains TRAP+
treat with cladribine (similar structure as adenosine, highly toxic to hairy cells when taken up)
AML translocation
myelogenous so no cell surface markers
median onset 65y
incr circulation of myeloblasts
Auer rods
Myeloperoxidase cytoplasmic inclusinos
APML subtype has t(15;17) translocation, responds to vitamin A which induces differentiation of promyelocytes
DIC is a common presentation (MPO released from Auer rods)
CML translocation
-gene product?
older age
hallmark is philadelphia chromosome t(9;22)
BCR-ABLfusion gene -> constitutively active tyrosine kinase -> WBC avoid apoptosis and accumulate in blood
incr levels of all granulocytes (ie basophils, neutrophils, eosinophils)
splenomegaly
very low LAP distinguishes it from leukemoid reaction (incr neutrophils with infection) b/c CML neutrophils don’t have LAP
cause of multiple myeloma
- symptoms
- treatment and mechanism
neoplastic B cells mature into plasma cells that make large amounts of Immunoglobulin or Ig fragments
suseceptble to proteasome inhibitors (eg bortezomib, a boronic acid containing dipeptide). w/o proteasome, toxic amoutns of protein accumulate in cell –> apoptosis
how does mycoplasma pneumoniae infection lead to mild transient hemolytic anemia
mycoplasma pneumoniae binds an oligaosaccharide (I-antigen) on resp epithelium that is also present on rbc surface
this leads to formation of cross-reacting IgM antibodies (cold agglutinin) that attach to rbc, activate complement and cause eryhtrocyte lysis
what is purpose of heparin bridge to warfarin (ie overlapping coadminstration of heparin)
warfarin most quickly reduces levels of Protein C (short half life) causing a transient hypercoagulable state -> warfarin skin necrosis
by what 2 mechanisms does ionizing radiation treat/palliate cancer
causes cell death by
- DNA double strand breakage (break both bc single strand breaks readily repeaired by polymerases)
- free radical formation (from ionization of water; O2 free rad cause cell and DNA damage)
radiation effects most pronounced in malignant cells bc they are rapidly dividing and thus less able to repair DNA damage
cause of anemia in SLE
formation of warm IgG autoantibodies against erthyrocytes
3 steps by which tumor invades basement membrane
- tumor cells detach from surrounding cells by decr expression of adhesion molecules (E-cadherins)
- adhere to BM, facilitate by incr expression of laminin and other adhesion molecules
- invade BM by enhanced secretion of proteolytic enzyme (eg metalloproteinase, cathepsin D proteasE)
HER2 positive breast cancer is treated with what? what is mechanism?
Trastuzamab
Monocolonal antibody htat binds HER2 and prevents activation of a transmembrane tyrosine kinase –> downreg cell proliferation and promote apoptosis
explain why someone with ESRD could have prolonged bleeding time
accumulation of uremic toxins, which impair platelet aggregation and adhesion
normal platelet count, PT, and PTT
uremic bleeding can be improved by dialysis which removes the toxins and partially reverse the bleeding abnormality
how does ristocetin cofactor assay work
it activates GPIb receptors and makes them available for vWF binding.
measures in-vitro vWF-depdent platelet agglutination. if vWF decreased, there is poor platelet aggregation in presence of ristocetin.
when add normal plasma (has vWF), appropriate platelet agglutination occurs
what is basophilic stippling due to
-what conditions can you see it in
abnormal degradation of RNA (lead inhibits a nucleotidase)
lead poisoning
sickle cell disease is due to what mutation
missense mutation
Glutamic acid replaced by Valine at position 6 in the hemoglobin beta-globin chain
what malignancies commonly metastasize to bone?
Prostate
breast
Kidney
Thyroid
Lung
overactivity of what intracellular enzyme can make people more susceptible to developing cancer from carcinogens
Microsomal monooxygenase. normally metabolizes toxins and foreign substances to make them soluble and easier to excrete
however it also in this way converts pro-carcinogens to carcinogens
amyl nitrite can be used as antidote for what poison? how does it work
cyanide
nitrites convert iron in hemoglobin to Fe3+ state creating methemoglobin. methemoglob doesn’t bind O2 but binds to cyanide with strong affinity -> sequestering cyanide in the blood so that it doesn’t bind cytochrom oxidase
(CN inhibits cytochrome oxidase, which is essential for ox phos -> severe lactic acidosis and death as a result of cells switching to anaerobic metabolism)
what three bone mets are osteoblastic?
prostate
small cell lung cancer
Hodgkin lymphoma
what two bone mets are mixed osteoblastic/osteolytic
GI, breast
why do reticulocytes appear blueish
residual ribosomal RNA
pure red cell aplasia can be caused by what three things
- thymoma
- lymphocytic leukemia
- parvo B19
under what conditions does sickling happen
- anoxia (low pH, high 2,3-bisphosphoglycerate)
- O2 unloading
- dehydration
what cell cycle phase does Retinoblastoma protein regulate? how?
active Rb serves as brake that prevents cell division
resting cells in G0 have active (hypophosphorylated) Rb protein.
when cell stim by growth factor, cyclin D, E and corresponding cyclin kinases CDK 4, 6 activated. Rb protein gets hyperphosphorylated (becomes inactive) and released E2F transcription factor, which allows cell to progress through G1 –> S checkpoint
aplastic anemia 5 causes
- autoimmune
- infections (parvo, EBV)
- drugs (carbamazepine, chloramphenicol, sulfonamides)
- exposure to radiation
- exposure to toxins (benzene, solvents)
Pancoast tumor location and symptoms
superior sulcus (lung apex)
shoulder pain (compression brachial plexus) Horner's syndrome (cervical sympathetic chain ganglia)
Superior Vena Cave syndrome tumor location and symptoms
compress SVC
impairs venous return from upper part of body -> dyspnea, facial swelling, dilated collateral veins in upper trunk
