Heme/onc Flashcards
why can deoxy blood carry more CO2 for a given PCo2 than oxygenated blood?
Deoxyhemoglobin is a better buffer of H+ than oxyhemoglobin
DIC (consumptive coagulopathy) develops when blood is exposed to large amounts of what over a brief period of time?
Tissue factor.
Causes massive generation of thrombin –> coagulation. Eg amniotic fluid embolism or abruptio placentae
Hashimoto’s is an autoimmune dz of the thyroid in which thyroid parenchyma is destroyed by lymphocytic infiltrate. This increases risk of what cancer?
Non-Hodgkin B cell lymphoma
Sjogren synd and chronic H pylori gastritis also inc risk of NHBCL
Asian diet predipsoses patients to high incidence of gastric adenocarcinoma due to high concentration of what?
Food preservatives (nitrosamines, polycyclic hydrocarbons, nitrites)
Fever, microangiopathic anemia, thrombocytopenia, renal insufficiency, and neuro problems caused by what?
Labs?
TTP:
Deficiency in a metalloprotease that cleaves ultralarge von Willebrand factor multimers that combine with platelets (ADAMTS-13)
Antibodies recognize ADAMTS-13
Labs: schistocytes, inc LDH
Lack of what cellular organelle in erythrocytes results in inability to synthesize heme?
Mitochondria
needed for first and last 3 steps of heme synth
What substance is secreted by hepatic parenchymal cells that controls Fe storage and release by other cells involved in Fe homeostasis?
Hepcidin
Precursor B-ALL or T-ALL?
TdT+, CD10+, CD19+
precursor B-ALL
Precursor B-ALL or T-ALL?
TdT+, CD2, CD3, CD4, CD5, CD7, CD8, CD1a
precursor T-ALL
B or T cell marker? CD5
T cell
B or T cell marker? CD19
B cell
How does ESRD cause bleeding problems?
Build-up of up uremic toxins impairs platelet aggregation and adhesion. Platelet count is normal
Define O2 content of the arterial blood?
What happens to it in methemoglobinemia?
Anemia?
Both dissolved O2 and O2 attached to Hb
Decreased in both methemoglobinemia and anemia
Define partial pressure of O2.
What happens to it in methemoglobinemia?
Anemia?
Dissolved o2 in the plasma - unrelated to Hb function
Normal in both methemoglobinemia and anemia
How does >1 body blood volume (5-6L) of whole blood transfusions or pRBC cause paresthesias?
Citrate (found in stored blood) will be elevated. Citrate chelates Ca and Mg, and may reduce their plasma levels –> paresthesia
Activating mutations of what gene lead to constitutional activation of EGFR pathway, promoting inc cell proliferation and growth?
KRAS
Tumors with mutation in KRAS can resist anti-EGFR drugs (eg cetuximab and panitumumab)
Recurrent vaginal Candida infections indicates a patient has what? This patient has risk of developing a malignant B-lymphocyte proliferation associated with what?
- HIV
2. EBV (latent EBV infection is present in 90% of nl individuals, with reactivation common in the immunosuppressed).
How does carbon tetrachloride cause hepatic necrosis and fatty change of the liver?
Free radical injury
Platelet endothelial cell adhesion molecule 1 (PECAM-1) is involved in what part of inflammatory leukocyte accumulation?
Transmigration
ICAM-1 and CD18 beta 2 integrins are involved in what part of inflammatory leukocyte accumulation?
Tight adhesion and crawling
L selectin (on neutrophils) and E/P-selectin on endothelial cells are involved in what part of inflammatory leukocyte accumulation?
Rolling
Which is more aggressive? HER2 or ER receptor positivity in breast cancer?
What drugs are used to treat these?
HER2 - assoc with signal transduction
Tx
- HER2: Trastuzumab
- ER: tamoxifen
As PO2 increases on the oxygen dissociation curve, what is released?
H+ and CO2 are released from Hb (Haldane effect), and O2 binding to Hb is increased.
This occurs in the lungs where pO2 increases.
Infections or use of sulfa drugs can cause hemolytic anemia if a patient has what problem?
G6PD deficiency (XR) - RBC use reduced NADPH to maintain glutathione to protect the cell against oxidative damage. RBC are more susceptible to oxidative damage during times of oxidative stress (eg use of sulfa drugs).
What drug targets a platelet surface glycoprotein receptor that binds fibrinogen to support platelet aggregation?
Abciximab - blocks GPIIb/IIIa
Melanoma and other tumors exhibit poor adhesion to what part of the ECM?
Fibronectin
Adhesion of cells to the ECM involves integrin-mediated binding to fibronectin, collagen and laminin. Differential integrin types affects adhesion
What is a significant adverse effect of ganciclovir therapy, especially with co-admin of zidovudine or TMP-SMX?
Neutropenia
What are common precipitating factors of G6PD deficiency anemia?
- infections
- Drugs: DAPSONE, antimalarials, sulfa drugs
- DKA
- fava beans
HER2 oncogene codes for what type of receptor that has tyrosine kinase activity? What is the function of the protein receptor?
Epidermal growth factor.
Accelerates cell proliferation
Patient with chronic pancreatitis can get macrocytic anemia how?
Diminished thymidine synthesis (impaired purine/pyrimidine synthesis) through Vit B12 and folate deficiency
Patient with new-onset neuro sx (numbness), anemia w/schistocytes, and thrombocytopenia likely has what?
TTP: Impaired cleavage fo vWF (def in ADAMTS13) –> prothrombotic
Patient on low calorie diet, abdominal pain, confusion and resolution with infusion of hemin is due to a deficiency in what enzyme?
Dx - acute intermittent porphyria
porphobilinogen deaminase deficiency plus ALA synthase induction (low calorie diet, meds, ETOH)
Note: Enzyme is also known as hydroxymethylbilane synthase or uroporphyrinogen I synthase.