BMS Exam III Flashcards
activated clotting factors
serine proteases
factor VIII deficiency
hemophilia A
tissue factor
thromboplastin
Warfarin/coumarin affects:
extrinsic pathway - blocks VKOR (vitamin K exposide reductase
Vitamin K, required cofactor
GLUTAMATION RXN for factors 2, 7, 9, 10 & Proteins C&S; post-translational MODIFICATION of several coagulation factors necessary for Ca+2 binding
reduced Vit K + clotting factors
γ-carboxyglutamate (GLA) = has high affinity binding site for Ca+2, which binds to coagulation factor
Anti-thrombin III (endogenous inhibitor)
inhibits all clotting factors (2, 7, 9, 10) that need factors that need Ca+2
HEPARIN activates anti-thrombin III
Protein C&S (endogenous inhibitor) inhibits
Va & VIIIa
TFPI (endogenous inhibitor)
inhibits TF-7A (similar to anti-thrombin III) = factors 2, 7, 9, 10 are inactivated
Intracellular PO4
intermediary metabolism in cells
Extracellular PO4
essential matrix mineralization
HIGH Ca+2 and PO4 in blood
CaPO4 = limited solubility – precipitate in soft tissue
1α-hydroxylase synthesizes (in kidneys)
calcitriol/vitD3 – rate limiting step: renal failure = major problem ; PTH simulates 1α-hydroxylase!
24-hydroxylase
deactivates vitD3 into calcitroic acid (regulation)
Ca+2 movement in intestine
paracellular + transcellular (Ca+2 channels)
Vitamin D deficiency
osteomalacia in adults, rickets in children
Vit D receptors
nuclear receptors = increase efficiency of translation
PTH
maintains plasma Ca+2 via GPCR signaling (Gs –> cAMP –> decreasing Gq, increaseing PLC
LOW plasma Ca+2
INCREASE in PTH release –> INCREASE plasma Ca+2 –> directly INCREASE bone resoprtion; DECREASE plasma PO4 because of PO4 excretion in urine (via Vit D)
PTH GPCR signaling
Uniquely DECREASES PTH release (negative feedback)
Majority Iron stored as
Ferritin (marcrophages + hepatocytes) – good indicator of iron levels
When iron is LOW in cells, IRP binds
mRNA binds 5’ to block translation of Ferritin (down regulation); binds 3’ end to increase synthesis of transferrin receptors
IRP bind 5’
down regulation = block Ferritin translation
IRP bind 3’
up regulation = increases transferrin receptors
IDA (Iron Deficiency Anemia)
Low serum ferritin, high level of transferrin – tx: ferrous sulfate + ascorbic acid
Anemia of Chronic Disease (ACD)
Cytokines stimulation hepcidin (inhibit ferroportin = down regulates intestinal absorption + releases Fe from macrophages) + inhibits erythropoiesis (decreased RBC production)
HIGH ferritin
ACD
Hemochromatosis
HFE defect, too much iron uptake inside cells; hepcidin cannot inhibit ferroportin
First substrates of heme metabolism
Succinyl CoA + glycine in mitochondria
First heme biosynthesis enzyme
ALA synthase
Acute Intermittent Porphyria (most common)
Defective PBG deaminase = neuropsychiatric symptoms + abdominal – TX: Hemin = repress ALA synthase
Porphyria cutanea tarda
Defective uroporphyrinogen decarboxylase – uroporphyrinogen build-up = photosensitivity
Heme Catabolism via macrophages in spleen, liver + red bone marrow
RBC –> hemoglobin –> heme –> biliverdin –> bilirubin –> (conjugated, more soluble) –> binds bile –>urobilinogen –> sterecobilin –> excreted in feces
Unconjugated (indirect) hyperbilirubinemia
Neonatal jaundice = UDP-glucuronyltransferas deficiency; Gilbert syndrom; hemolysis
Conjugated (direct) hyperbilirubinemia
Hepatobiliary disease + bile stones (bile duct obstruction)
G6P dehydrogenase
Rate limiting step in nucleotide metabolism in PPP
Two PPP defects
G6PD deficiency = cannot produce NADPH, gluthathion not reduced»_space; build up of H2O2»_space; hemolytic anemia (associated with Type I hypersensitivity)
Anti-coagulant Drugs
Heparin; Thrombin II & Factor X Inhibitors (dabigatran or rivaroxaban = not better than heparin); Coumarin/Warfarin
Hemophilia B
Factor IX deficient
Heparin (IV, parenteral)
Bind anti-thrombin III (interferes with all steps of coagulation) –> inactiavtes thrombin (HMW, long) and factor Xa (LMW, short + HWM, long) — tx: venous thrombosis, pulmonary embolism, myocardial infarction, unstable angina — sf(x): bleeding, heparin induced thrombocytopenia (HIT anemia) = low platelet count
Reverse Heparin
Protamine (binds Heparin)
Warfarin *increases coagulation risk for first 3 days
Inhibits Vit K Epoxide Reductase (VKOR) – interferes w/ clotting factor production in liver… bleed out; DDI = aspirin + preggo women b/c vitamin K for bone development (teratogen) – tx: venous thrombosis, ishemic stroke, pulmonary embolism – sf(x): increases coagulation risk for first 3 days… prevent via heparin bridge or thrombosis due to protein C deficiency
Reverse Warfarin
Vitamin K
aPTT
Monitor bleeding time on pts on heparin or thrombin II inhibitor (dabigatran)
PT, INR
Monitor bleeding for Warfarin
Lepirudin
Alternative to heparin – Thrombin (Factor IIa) + prothrombin (Factor X) inhibitor – sf(x): bleeding (aPTT)
RivaroXaban MOA
Factor X (prothrombin) inhibitor – clincal use: nonvalvular atrial fibrillation; sf(x): bleeding
DabigaTran MOA
Factor IIa (thrombin) inhibitor
Anti-Platelet Drugs
Aspirin + Clopidogrel, blocks platelet activation and aggregation
Aspirin MOA
Blocks TXA2 (platelet AGGREGATION) –> reduces production of platelets
Clopidogrel (Plavix)
Prevents ADP from binding to receptor on platelets (blocks platelet ACTIVATION) – tx: acute coronary syndrome, prevents restenosis after percutaneous coronary intervention (PCI), arterial thrombosis
Prevent + tx of atererial thrombosis
Aspirin + Clopidogrel
Abciximab (parenterally, IV)
Anti-Platelet Drug, interferes with GP IIb/IIIa – binding to fibrinogen and other ligands
Percutaneous coronary intervention (PCI)
Abciximab – only given parenterally – sf(x): bleeding, thrombocytopenia (anemia)
Fibrinolytic drugs
Urokinase or tPA; Alteplase, Reteplase, Streptokinase – tx: coronary artery thrombosis, ischemic stroke, pulmonary embolism
tPA, MOA
plasminogen –> plasmin (cleaves fibrin = reverses blood clot) – sf(x): cerebral hemorrhage – ANTIDOTE: Aminocarproic acid
Vitamin D supplements
Cholecalciferol, ergocalciferol, calcitriol – tx: osteoporosis, rickets/osteomalacia, renal failure, malabsorption
Vitamin D
inhibits PTH, increases Ca+2 and PO4 serum, prevents excretion?
Calcidiol
produced in liver, measurable levels of vitamin D
Vit D toxicities
Hypercalcemia, hypercalciuria (excretion of Ca+2)
Osteoclast action, vit D and PTH
INCREASE
Furosemide
For hypercalcemia = inhibition of the Na/K/2Cl transporter in the ascending loop of Henle → (↑) Ca+2 excretion, (↑) urine Ca+2 and Mg – sf(x): hypokalemia, ototoxicity, hyperuricemia, hypomagnesmia
Ototoxicty
Furosemide
Bisphosphonate, MOA
Suppreses bone resorption (inhibits osteoclast activity via inhibition of farnesyl pyrophosphate synthesis) – tx: Paget’s disease, osteoporosis, hypercalcemia, bone metastasis – sf(x): GI irritation, renal failure, osteonecrosis of jaw
Bisphosphonates = “dronate”
*Fosomax = Alendronate, Risendronate, Ibandronate, Zolendronic acid
Raloxifene (SERM)
Selectively interacts w/ estrogen receptors = bone (agonist), breast + endometerium (antagonist) = Used for osteoporosis, reduces vertebral fracture risk – sf(x): thromboembolism, hot flashes
Calcitonin (nasal spray)
Hormone that acts via cognate GCPR = tx: osteoporosis + hypercalcemia
Denosumab (monoclonal Ab, given subcutaneous injection every 6 months)
Blocks bone resorption (binds RANKL = stimulates osteoclast) – tx: osteoporosis – sf(x): increased risk of infection
Terparatide (PTH, not parathyroid hormone) via subcutaneous injection
Amino acid 1-34 or all 84 PTH, regulates Ca+2 and PO4 metabolism in bone + kidney. Stimulates bone turnover –> net bone formation!
Side effects of Terparatide (PTH)
Prolonged use can match bone formation and resorption, hyper calcemia, hypercaluria
Sulfonamide, MOA
Block folate production, targets bacterial PABA
Trimethoprim
Anti-folate: selectively inhibits DHFR
Metrotrexate
Blocks DHFR –> interferes with biosynthesis of dTMP and purines == tx: inflammatory bowel disease, rheumatoid disease, cancer chemotherapy
5-FU (flurodeoxyuryidale)
Blocks thymidylate synthase so blocks dUMP → dTMP