uworld Flashcards
man with HIV, LAD in the superficial inguinal nodes, where is the origin?
anal orifice; cutaneous lymph below umbilicus drains to superficial inguinal lymph nodes except penis and posterior calf
mediastinal mass in teenager, causing dysphagia with blasts on smear
T-cell ALL
northern blot with 3 different transcripts identified exhibits what principle?
alternative splicing
spherocytosis effect on MCV, and other parameters?
normal or low, due to dehydration and MCHC is also high because smaller
woman with anemia given folate, comes back with neuro deficits?
B12 deficiency treated with folate worsens neurological symptoms
different stages and colors of bruises caused by what enzyme?
heme oxygenase
what receptors used for antiemetic drugs? in chemotherapy?
Neurokinin1 and 5-HT3
15,17 balanced translocation in person with bleeding, Pt/PTT increased, d-dimer increased, low fibrinogen. what protein is mutated in this patient? Diagnosis and mechanism?
retinoic acid receptor in acute promyelocytic leukemia, accumulation of cells with primary granules, which increase risk of DIC
chloramphenicol in pregnancy
“Gray baby” syndrome
bactrim in pregnancy
neural tube defects
mRNA processing steps and location
5’ methylated cap, poly A tail, intron/exon splicing- exit nucleus, then P bodies in cytoplasm regulate and degrade
what contributes to the pathology of T2DM?
free fatty acids; they cause impaired glucose uptake and increases hepatic gluconeogenesis
hemorrhagic cystitis with cyclophosphamide, can give what to prevent it?
mesna, 2-mercaptoethane sulfonate
mediterranean guy with microcytic anemia with pokilocytes and target cells, Hb A2 is elevated, what is the mechanism of anemia?
mRNA processing defect in Beta thalassemia
mechanism of radiation therapy
breaks double strand DNA and formation of free radicals
vincristine SE and mechanism
neurotoxicity due to inhibition of MT polymerization
person travelling to africa gets meds and vaccinated, then comes back with jaundice: dx and pattern of inheritance; what do you see on peripheral smear
G6PD, X-linked recessive, heinz bodies
aminoglycosides in pregnancy
otoxtoxicity and vestibulotoxicity
malignant tissue biopsy has blue cells, what enzyme is active? and where
RNA polymerase 1, in nucleolus- makes rRNA
2 unique things about Ecoli O157:H7
- does not ferment sorbitol. 2. no glucoronidase
what is 2,3 BPG, how is it produced, and its function?
a byproduct of glycolysis produced in RBCs, which sacrifices a net gain of ATP to make this. 2,3 BPG decreases Hb affinity for oxygen (causes right shift in O-H curve) and thus facilitates increased delivery of O2 in times of hypoxia and chronic anemia
light’s criteria
- fluid protein/serum protein > 0.5; 2. fluid LDH/serum LDH >0.6; 3. fluid LDH > 2/3 normal limit of serum LDH
why is HbS clinically worse than HbC? what are the mutations? how does HbS affect O-H curve
glu –> valine and glu –> lysine, respectively. Because valine is hydrophobic and lysine is charged, hydrophobic valine can cause clumping of Hb and sickling of RBC. Causes right shift because it favors deoxygenated state.
mutation in the protein that interacts with transferrin receptor, what is it and what does it lead to?
HFE, causes upregulation of DMT1, then hemochromatosis, cirrhosis and HCC
thrombocytopenia with no other features, pt is normal, dx?
ITP; vWD does not have thrombocytopenia and has prolonged pt
immigrant with anemia, pyruvate kinase deficiency and splenomegaly. what is mechanism for spleno?
pyruvate kinase deficiency causes hemolytic anemia because ATP from RBC is not generated and membrane gradient cannot be maintained. The red pulp removes dead RBC, so undergoes hyperplasia
STAT pathway, non-tyrosine kinase mutation in a hematopoietic cells, anemia and splenomegaly. what group of diseases?
chronic myeloproliferative diseases, except CML
folate deficiency, can give what else to prevent apoptosis?
thymidine
man with CRAB, treated with agent that blocks proteasome site, mechanism of action?
proteasome inhibition leads to accumulation of proteins that cause apoptosis. IgG is mass produced in multiple myeloma so very effective
on hemoglobin electrophoresis, rank A,S,C in terms of distance from - charge, and give rationale
C,S,A because of Valine is neutral, Lysine (HbC) is positive
girl with infectino, giant pronormoblasts in bone marrow biopsy with inclusions, dx and epi?
parvovirus B19 causing aplastic crisis, esp in patients with hemolytic dz
person with pneumonia, and WBC and LAP is up, what other findings are there?
basophilici granules called dohle bodies
HCC with foreign DNA
HBV, inserts DNA into host
mechanism of multiple myeloma and signs of mm
RANK activation leads to osteoclast stimulation; CRAB
GVHD
occurs after bone marrow transplantation OR of any organ rich in lymphocytes such as liver. Systemic involvement in GI, skin, and liver point to it being a GVHD as opposed to transplant rejection which affects only the transplanted organ
agitated elderly woman with BPS symptoms, what drug?
haloperidol and not lorazepam because of SE of latter
tachyphylaxis
when use of drug causes negative feedback and rebound symptoms because endogenous products are not made, i.e decongestants
hemophilia carrier in mother, whats the chance it will be passed to child of unknown sex?
1/8
CO poisoning, effect on dissociation curve and PaO2
decreases o2 content but not dissolved o2 (PaO2) and decreases unloading of O2 in tissues
cerebellum brain tumor in child, solid and cystic components
pilocytic astrocytoma
leukocytosis with promyelocytes and myelocytes, and leukocyte alkaline phosphatase is low, dx?
CML, because it’s ALP is low, usually high in leukemoid reaction
forceps or vacuum can lead to?
subdural hematoma (cortical bridging veins) or epidural hematoma (middle meningeal artery)
anterior mediastianal mass with progressively declining response on EMG, what anesthesia drug is powerful?
MG- because receptor number is low, a non-depolarizing agent like vercuronium is very powerful. succinylcholine is depolarizing agent, which is a competetive agonist competing for the same spot, so not as effective
patient with cLL, given tx that inhibits BCL-2, result?
activation of caspases via leak of cytochrome C
sickle cell trait:
normal, asymptomatic, more Hb F and Hb A than Hb S, protective against malaria
anemia after infection with walking pneumonia, why does it resolve after 2 months?
IgM from cold agglutinins disappear, they are initially formed due to molecular mimicry
what is this test- take a protein of interest, gel electrophoresis, transfer to filter, then use Ab to IHC? how about for DNA binding protein, DNA, RNA?
western blot; southwestern, southern, northern respectively
extra nitroprusside treatment
cyanide poisoning; so must give sulfur group (using sodium thiosulfate) to make thiosulfate –> which is less toxic and excreted in urine.
what causes cachexia in cancer and what is the mechanism?
TNF-a; suppresses appetite in the hypothalamus and increases basal metabolic rate
chronic opioid use leads to?
tolerance of analgesic and side effects, except constipation and miosis
old man with paresthesia and gait ataxia, what is the cause?
B12 deficiency due to strict vegan diet for 6 years
CNS lymphoma in HIV caused by?
EBV virus, predominant in B lymphocytes
cause of macrocytosis in sickle cell
increased folic acid requirements due to high turnover of erythrocytes
telomerase activity highest in?
stem cells; because they need to reproduce often, must stay alive longer!
mucor infection what to look out for after initiating rx?
magnesium and potassium because Ampho B can cause nephrotoxicity
which enzyme, when overactive, causes cancer? and how
microsomal monooxygenase (Cytochrome P450); by converting procarcinogens into carcinogens
excretion rate of susbstance A?
total filtration rate - total reabsorption rate of A
where does complement bind antibody?
Fc region, near the hinge point
tumor cells with mismatch repair and high microsatellite instability, why are they especially susceptible to PD-1 immunotherapy?
because a lot of neoantigens. a lot of non-self proteins which will be recognized as T-cells as foreign and destroyed, now that PD-1 immune evasion strategy is not working
leukocyte migration PECAM-1 involved in which step?
Transmigration- PECAM-1 inbetween endothelial cells
bone cancer that mets to lungs, sheets, and vascular fibrous septae, diagnosis and epidemiology?
Ewing sarcoma, 2nd most common bone cancer of childhood after osteosarcoma
anterior pituitary gland embryological origin
surface ectoderm
pneumocystic pneumonia, oral ulcers and a new rash, cause?
HHV-8, Kaposi’s sarcoma
chemotherapy patient having neurological symptoms, caused by which drug and what mechanism?
vincristine, MT inhibitor, prevents M phase of cell cycle
heparin overdose causing intracranial bleed, rx?
protamine- binds to heparin and inactivates it
what causes left shift of Hb dissociation curve?
ACE bats right- acid, co2, exercise, 2-3bpg, altitude, temperature
tetracycline in pregnancy
teeth staining
lack of which organelle affects heme production?
mitochondria
how do tumor cells evade immune system and how to prevent?
PD-1 ligand to exhaust T cell, can give PD-1 antibody
hemolytic anemia, hypercoagulability, and pancytopenia, lack of CD55, dx and mechanism?
PNH, no GPI, which prevents DAF/MIRL which prevent complement activation
pigment inclusion in lysosomes in liver, epinephrine metabolites
Dubin-Johnson, GC/DR = direct hyperbilirubinemia, defect in transport
what does oxygen dissociation curve look like if Hb subunits are separated?
hyperbolic like myoglobin
patient just started on warfarin, skin necrosis happens, mechanism?
warfarin inhibits epoxide reductase, which blocks new production of factors and protein C and S. Protein C has short half life, which means skin necrosis!
PCR, what do you need to amplify?
flanking region sequence to make primers to anneal
neurophysins
proteins involved in posttranslational hormone processing and stabilization during axonal transport for ADH and oxytocin
woman with GN, rash, arthralgia has prolonged APTT and falsely positive VDRL, common complication for this woman and dx
antiphosphoipid antibodies in SLE, causing recurrent miscarriages due to thromboembolism
ectopic pregnacy, given methrotrexate, what accumulates in embryonic tissue?
dihydrofolate polyglutamate; MTX inhibts DHF reductase which reduces folic acid to DHF and THF. so DHF will increase because it cannot be made in to THF
horse erythrocytes agglutinate when exposed to patient’s serum, what is the cancer caused by the agent?
NPC- EBV
arginase deficiency
arginase is used in urea cycle, deficiency causes spastic diplegia, growth delay, abnormal movements. tx: arginine free diet
dysthymia criteria
2 years, 2 sxs + depression
2 ways of calculating CO
CO = HR * SV or CO = rate of o2 consumption/(arterial O2 -venous O2)
spleen of sickle cell patients
fibrosis and scarring due to repeated infarctions and vaso-occlusions. after autosplenectomy more vulnerable to encapsulated organisms
digeorge syndrome, where in the lymph node is there degeneration?
paracortex
DNA-binding proteins include (4)
steroid hormone, thyroid hormone, transcription factors, fat soluble vitamin receptors
rRNA is synthesized in which intracellular organelle?
nucleolus
SSSS
caused by exotoxin from staph species, usually in young children with nikolsky’s sign
how does HOCM lead to SCD
due to ventricular arrhythmia, aberrant course of conduction
gingival bleeding girl, platelet with riscocetin doesn’t work well. give normal plasma and it works: dx and mechanism
VWD; riscocetin activates GP1b on platelets so it can agglutinate to vWF, but if don’t have in first place then no use
what to give in atropine toxcity (drug and class)
physostigmine (anticholinergic) because it can cross bbb unlike pyridostigmine, neostigmine, edrophonium.
pregnant mom with woody hard uterus, and signs of DIVC. Cause and mechanism?
tissue thromboplastin in maternal circulation, damage to placenta releases TT in mom’s circulation, causing activation of extrinsic pathway, leading to widespread consumption coags and platelets
vWF binds where and what does it do
binds subendothelial collagen, then platelets can bind vWF using Gp1b receptor. vWF also stabilizes clotting factor VIII
inferior surface of heart is supplied by?
right coronary artery; 85-90% of people are right dominant, meaning RCA supplies PDA (posterior descending artery) which supplies inferior part
neonatal IVH
originates from germinal matrix in premature, low-birth weight infants because of a lack of glial fiber support and autoregulation of BP
iron is regulated by what in the body and produced where and what does it do?
hepcidin from hepatic parenchymal cells, it regulates iron via ferroportin. hypoxia and increased erythropoiesis lowers hepcidin, inflammation and high iron levels increases hepcidin.
multiple ring-enhancing lesions in CNS for HIV patient
toxoplasmosis; treat with fansidar (pyrimethamine and sulfadiazine)
CCl4 mechanism of damage/cell injury, liver necrosis?
CCl4 is converted to CCl3, a free radical, by the P450 system. This leads to lipid peroxidation and cell injury which leads to fatty change and necrosis
metachromatic granules, aniline dyes and mechanism of toxin
diphteria, AB toxin causes impairment of protein synthesis by ADP-ribosylating EF-2
