Heme and Onc Flashcards
complications of lead poisoning
- neurologic (cognitive impairment, irritability)
- GI (constipation, abdominal pain)
- renal (interstitial nephritis)
- hematologic (anemia)
- lead lines on gingivae (Burton lines) and on metaphyses of long bones on x-ray
- erythrocyte basophilic stippling
- drops-wrist and foot drop
most of the cutaneous lymph from the umbilicus down, including the anus below the dentate line, drains to the ______________
superficial inguinal lymph nodes
exceptions: glans penis and posterior calf, which drain to the deep inguinal nodes
sickle cell patients have increased risk for bacteriemia due to
Streptococcus pneumoniae and Hemophilus influenza
because these patients become functionally asplenic
function of hepcidin
polypeptide synthesized by liver that acts as the central regulator of iron homeostasis
low hepcidin levels increase intestinal iron absorption and stimulate iron release by macrophages
what is the Kozak consensus sequence
occurs on eukaryotic mRNA and defined as: (gcc)gccRccAUGG, R is either adenine or guanine
sequence helps initiate translation at the methionine start codon (AUG)
appearance of RBC in beta thalassemia
hypochromic, microcytic anemia
-increased central pallor, anisopoikilocytosis (variation in size and shape), target cells, tearrop cells, nucleated red cell precursors, and basophilic stippling
unpaired alpha chains precipitate within red cells and cause membrane damage, leading to ineffective erythropoiesis and extravascular hemolysis
how come hepatitis B can integrates its DNA into the host genome but hepatitis C can’t
because hep C is an RNA virus that lacks reverse transcriptase to help it integrate its DNA into the host genome
function of von Willebrand factor
binds glycoprotein (GP) Ib receptors on platelet membrane and mediates platelet aggregation and adhesion to subendothelial collagen
also serves as a carrier for factor VII and stabilizes it
characteristics of inflammatory breast cancer
dermal lymphatic invasion by breast carcinoma
poor prognosis
peau d’orange: erythematous, itchy breast rash with skin texture changes analogous to an orange peel
what is bleeding due to heparin toxicity treated with
protamine sulfate
can’t be used for warfarin overdose
what to use for warfarin overdose
vitamin K (takes time)
fresh frozen plasma
can’t be used for heparin overdose
how does cyanide toxicity work? and how is it treated?
toxicity: bind ferric iron (Fe3+) with high affinity, inhibiting cytochrome c oxidase in mitochondria (needed for oxidative phosphorylation)–> lactic acidosis and death
treat: inhaled amyl nitrite
how does inhaled amyl nitrite treat cyanide poisoning?
it oxidizes ferrous iron (Fe2+) in hemoglobin to ferric iron (Fe3+), generating methemoglobin
methemoglobin can’t carry oxygen but has high affinity for cyanide
hemorrhagic cystitis is an adverse reaction to which two drugs
cyclophosphamide or irosfamide (nitrogen mustard-based chemotherapy) from the urinary excretion of the toxic metabolite acrolein
can be prevented by aggressive hydration, bladder irrigation, and administration of mesna (binds acrolein)
Gianzmann thrombassthenia
autosomal recessive disorder that is caused by a deficient or defective glycoprotein (GP) IIb/IIIa on platelet surfaces.
presents in childhood with mucocutaneous bleeding
peripheral smear snows no platelet clumping
mechanism of action of abciximab
blocker of GP IIb/IIIa receptor, which normally promotes platelet binding to fibrinogen
treat unstable angina and acute coronary syndrome
BRCA1 and BRCA2 are tumor suppressor genes involved in what process
repair of double-stranded DNA breaks
mutation- autosomal dominant with variable penetrance
increased risk of developing breast and ovarian cancer
characteristic of polycythemia vera
primary polycythemia
increased RBCs
intense itching after hot shower, erythromelalgia (severe, burning pain and red-blue coloration) due to episodic blood clots in vessels of extremities
decreased erythropoeitin
treat: phlebotomy, hydroxyurea, ruxolitinib (JAK1/2 inhibitor)
why do you need to check G6PD levels before administering dapsone?
to prevent hemolytic anemia in those with G6PD deficiency
Dapsone puts oxidative stress on body
where does isotype switching of immunoglobulins occur?
germinal centers of lymph nodes and requires interaction of CD40 receptor on B-cells with the CD4- ligand CD154) expressed by activated T-cells
difference between topoisomerase I and topoisomerase II
I- makes single-stranded nicks to relieve negative supercoiling
II-induces transient breaks in both DNA strands simultaneously to relieve both positive and negative supercoiling
mechanism of action of etoposide
chemotherapeutic agent that inhibits the sealing activity of topoisomerase II
what is negative selection in T cell maturation?
eliminate T cells that bind to self MHC or self antigens with overly high affinity
occurs in thymic medullla
prevent autoimmunity
leukocyte adhesion process- step 1
1) margination: increased vascular leakage in microvasculature leads to hemoconcentration and decreased wall shear stress, improving contact of neutrophils with endothelial lining
leukocyte adhesion process-step 2
2) rolling: neutrophils roll on endothelium via loos binding of sialylated carbohydrate groups such as Sialyl Lewis X or PSGL-1 to L-selectin on neutrophils or E-selectin/P-selectin on endothelial cells
leukocyte adhesion process-step 3
3) activation: slow rolling allows leukocytes to sample chemokines secreted by inflamed tissue. this activates integrins by inducing signaling cascade that results in conformational change in integrins necessary for binding
leukocyte adhesion process-step 4
tight adhesion and crawling: neutrophils become firmly attached to endothelium via binding of CD18 beta 2 integrins (Mac-1 and LFA-1) to intercellular adhesion molecule-1 (ICAM-1) on endothelial cells
leukocyte adhesion process- step 5
transmigration: neutrophils eventually migrate out of the vasculature by squeezing between cells via integrin attachments and adherence to platelet endothelial cell adhesion molecule 1 (PECAM-1)
mechanism of action of rivaroxaban and apixaban
oral anticoagulant that directly inhibits factor Xa
used in venous venous thromboembolism and atrial fibrillation
what are cytokeratins
proteins that help form the keratin-containing intermediate filaments that make up the cytoskeleton of almost all epithelial
marker for epithelial-derived tumors
classic triad of paroxysmal nocturnal hemoglobinuria
hemolytic anemia (hemoglobinuria), pancytopenia, and thrombosis at atypical sites
due to a gene defect that leads to uncontrolled complement-mediated hemolysis
chronic hemolysis–> iron deposition in the kidney (hemosiderosis)
sickling episodes of sickle cell disease results in hemolysis, which leads to
increased indirect bilirubin and lactate dehydrogenase
decreased levels of haptoglobin
what are Reed-Sternberg cells
giant binucleated cell derived from germinal center B-lymphocytes and are the neoplastic cells of Hodgkin lymphoma
owl’s eyes
association between vitamin B12 and folate deficiency and treatment
moderate improvement in the hemoglobin level often occurs when a deficiency in vitamin B12 is treated with folate, or vice versa
treatment of vitamin B12 deficiency with folate alone can actually worsen neurologic dysfunction
characteristic laboratory abnormalities of hemolytic uremic syndrome
decreased hemoglobin and platelet count and increased bleeding time, lactate dehydrogenase, bilirubin, BUN, and creatinine
HUS –> acute kidney injury, microangiopathic hemolytic anemia, and thrombocytopenia
how does bone metastases assists in cancer diagnosis?
osteolytic (lucent): due to osteoclast stimulation, tend to represent aggressive cancer
osteoblastic (sclerotic): due to osteoblasts, indicates a more indolent course
how does chronic myelogenous leukemia (CML) differs from leukocytosis
have decreased leukocyte (neutrophil) alkaline phosphatase while that is normal or elevated in a leukemoid reaction
presentation f von Willebrand disease
lifelong history of mucosal bleeding, including gingival bleeding, epistaxis, and/or menorrhagia
normal platelet levels but porlonged bleeding time due to impaired platelet functioning
2 important functions of van Willebrand factor
- promotes platelet adhesion by binding and crosslinking platelet glycoproteins (primarily GpIb) with exposed collagen underneath damaged endothelium
- protective carrier protein for factor VIII