Heme Oncology Flashcards
Hypersegmented neutrophils are seen in what disease? What is the defect/pathology?
Megaloblastic anemia: -impaired DNA synthesis (low B12 and/or folate) -cell cycle cannot G2–> Mitosis. Continued cell growth w/o division–> Macrocytes
What are causes of folate deficiency?
Malnutrition (alcoholics) Malabsorbtion Anti-folate Rx (methotrexate, trimethoprim, phenytoin, sulfonamides) Pregnancy, Hemolytic anemia (increased need) Cancer (use up for DNA..)
How does folate deficiency present?
Hyperseg neutrophils Glossitis Increased Homocysteine, but normal methylmalonic acid levels *no neuronal findings* Neural tube defects (fetus)
Risks for Homocystenemia?
…
Significance of Folate/Folic acid?
After conversion to THF, is is a coenzyme for 1-cabon transfer (methylation) rxns. Necessary for making nitrogenous bases in DNA & RNA.
What is vitamin designation for folic acid? Where is it found?
Vitamin B9 Natural source, Folate, found in lefy green veggies. Small reserve in liver. “FOLate from FOLiage”
What specific reaction is Folic acid used for DNA?
Pyrimidine base production dTMP
What does increase band cells indicate?
Increased myeloid proliferation. Ex:
- bacterial infection
- CML
Describe contents of Neutrophil large and small granules
Small: more numerous
- Alkaline phosphatase
- Collegenase
- Lysozyme
- Latoferin
Large Azurophilic (lysosome)
- Acid phosphatase
- Peroxidase
- ß-glucoronidase
Describe appearance of monocytes. What is normal % in CBC?
Kidney-shaped nucleus with frosted glass cytoplasm.
3-7%
Function of Macrophages
- Phagocytose
- bacteria
- cell debris
- old RBCs
- APC via MHC II
What activates macrophages?
What is surface marker of macrophage?
gamma-interferon activates.
Marker CD14.
Causes of eosinophilia?
“NAACP”
- Neoplastic
- Asthma
- Allergic process
- Collagen vascular diseases
- Parasites (invasive, like helminths)
What enzymes eosinophils make?
What are eosinophils highly phagocytic to?
Make histaminase and arylsulfatase
target Ag-b complexes
Function of basophils?
Mediates allergic rxns
What are contents of basophil granules?
- Histamine (vasodilation)
- heparin (anticoagulant)
- leukotriene (LTD4)
List WBCs from normal CBC in descending % (give %s)?
Normal WBC range?
“Neutrophil Like Making Everything Better”
- Neutrophils (54-62%)
- Lymphocytes (25-33%)
- Monocytes (3-7%)
- Eosinophils (1-3%)
- Basophils (0-0.75%)
Normal WBC range: 4-10K cells/mm3
Platelet granules and contents?
Dense granules
- ADP
- calcium
Alpha-granules
- vWF (receptor GpIb)
- fibrinogen (receptor GpIIb/IIIa)
Where are PLTs stored? How much?
1/3 stored in spleen
What is receptor for vWF?
GpIb
What is receptor for Fibrinogen?
GpIIb/IIIa
What is the energy source of RBCs? What pathways are it used in and %distribution?
Glucose 90% in glycolysis 10% in HMP shunt (Pentose Phosphate Pathway)
What damage can free radicals cause?
- Lipid membrane peroxidation
- Protein modification
- Breaking DNA
Where do free radicals come from?
- Radiation
- Drug metabolism; PHASE I
- Redox rxns
- Nitric Oxide
- Transition metals (Iron, etc)
- Iron must be found in body (prevent Fenton rxn)
- Leukocyte oxidatie BURST
What role does glutathione have in RBCs?
- in reduced form, it is an antioxidant.
- converts H2O2 to water
- Reduced by NADPH
- If not reduced, it will cause oxidative stress–> Hemolysis
- G6PD deficiency
What prevets free radical injury?
- Antoxidants
- Vit A, C, E
- Glutathione
- Uric acid
- Coenzyme Q
- Enzymes
- Catalase
- Superoxide dismutase
- Gluathione peroxidase
- Spontaneous decay
Pathalogies of free radical injury?
- iron overload (heochromatosis)
- retinopathy of prematurity
- bronchopulmonary dysplasia
- carbon tetrachlorida –> liver necrosis (fatty change)
- Acetaminophen overdose (fulminant hepatitis)
- Repurfusion after anoxia (superoxide)
- 3 hrs after stroke
- after thrombolytic treatment
Repurfusion damage. How?
- Superoxide O-
- Mitochondrial damage
- Inflammation (increased neutrophil)
- Compliment activation
What is the purpose of HMP shunt (Pentose Phosphate Pathway)?
- Alternative route for glucose oxidation w/o using ATP.
- Generates NADPH .
- Produces pentose sugars
- Ribose 5-P (for DNA)
- Glycolytic intermediates: G3P, F6P
Write out the Pentose Phosphate Pathway/ HMP shunt.
Differentiate oxidative and nonoxidative portion.
FA, pg 103
Lange card #8
Oxidative (irrev) makes Ribulose 5-P, CO2, & 2 NADPH
Nonoxidative makes Ribose 5P, G3P, F6P.
Where does HMP shunt located?
Cytoplasm of liver cells, adrenal cortex, and lactating mammary glands.
(site of FA or steroid synthesis)
Function of NADPH?
Reduce free radicals and peroxides. Keep glutathione in reduced state.
Used in FA and Chol synthesis.
Deficiency in B12 and/or Folic Acid has neurological Sx?
Explain path & Biochem of Neuro Sx.
B12 defciency (not folate)
B12 a cofactor for Methylmalonyl-CoA Mutase, for conversion of MM-CoA to Succinyl-CoA. If B12 deficiency, MM-CoA converted to Methylmalonic Acid, a myelin destabilizer. Excessive MMA will prevent normal fatty acid synthesis, or it will be incorporated into fatty acid itself rather than normal malonic acid. If abnormal FA incorporated into myelin, the resulting myelin will be too fragile, and demyelination will occur.
Beta-thalassemia minor Sx & in lab how is it confirmed?
No Sx!
Confirmed on electrophoresis with increased HbA2 (>3.5%).
Differentiate Beta-thalassemia minor, major, and HbS/Beta heterozygote regarding Hgb chains. Disease severity.
- ß-thal minor (heteroz): ß chain underproduced-> no Sx. Decreased Hgb A, increased Hgb A2 (5%, normal 2.5%), and Hgb F (2%, normal 1%)
- ß-thal major: ß chain absent → severe anemia, presents few months after birth (HgbF temporarily protective)
- increase fetal Hgb, HbF (α2γ2). Little to no HgbA. Increased Hgb A2.
- HbS/ß-thal (heteroz): varible ß-globin production. Mild to moderate sickle disease.
Desribe ß-thalassemia
Point mutation in splice site and promoter sequence–> decreased ß-globin made genetically
Which race/demo is ß-thalassemia common in?
Mediterranean & African
Describe Sx of ß-thalassemia major and causes
Skeletal deformities; Chipmunk facies
X-ray: “crew cut” skull appearance due to marrow expansion (like in sickle cell Xray), due to Massive erythroid hyperplasia.
Extramedullary hematopoiesis with hepatosplenomegaly
What enzymes do lead inhibit? what pathway are they from?
From Heme synthesis, enzymes inhibited by lead:
Ferrochelatase & ALA dehydratase
How does Lead cause basphilic stippling?
Lead inhibits rRNA degradation, causing RBCs to retain aggregates of rRNA
First line of Tx for Lead intoxication?
Dimercaprol & EDTA.
Kids can also get Succimer for chelation.
Sx of Lead poisoning
LEAD:
- Lead lines on gingiva (Burton’s lines) and on metaphyses of long bones on x-ray
- Encephalopathy & Erythrocyte basophilic stippling
- Abdominal colic and sideroblastic Anemia
- Drops- wrist nd foot drop. Dimercaprol & EDTA 1st line for Tx.
Causes of Sideroblastic anemia (genetic and acquired)
- X-linked defect in δ-ALA synthase gene
- EtOH, lead, & Isoniazid (inhibits cofactor Vit B6). Reversible.
Lab presentation of Sideroblastic anemia
Ringed sideroblasts (w/ iron-laden mitochondria)
↑ Iron, ↑ Ferritin. Normal to low TIBC, ↑%sat
How do you treat Sideroblastic anemia
Pyridoxine (B6, cofactor for δ-ALA synthase)
What does PTT test?
Common & intrinsic pathway (all factors except 7 & 13)
What does PT lab value test?
Comon & extrinsic pathway
(factors 1, 2, 5, 7, 10)
What are Sx of Hemophilia
Macrohemorrhaging:
hemarthroses (bleeding in joints), easy bruising, and elevated PTT