Unit 1 Flashcards
1
Q
What is an H&E stain?
A
Hematoxylin & eosin stain
H –> binds nuclei (basic) –> becomes blue
E –> bind cytoplasm/proteins (acidic) –> becomes pink, orange, red
2
Q
What are normal RBC values?
A
Male: 4.8 - 6.1
Female: 4.2 - 5.6
3
Q
What are normal hemoglobin values?
A
Male: 14 - 18
Female: 12 - 16
4
Q
What are normal hematocrit values?
A
Male: 39 - 50
Female: 35 - 46
5
Q
How do you distinguish eosinophils on a smear?
A
Numerous red-orange granules in the cytoplasm
6
Q
How do you distinguish basophils on a smear?
A
Numerous large round purple-black cytoplasmic granules; frequently covering the nuclear lobes
7
Q
How do you distinguish monocytes on a smear?
A
Large & eccentric nucleus (kidney or horseshoe shaped)
Cytoplasm has a foamy appearance
8
Q
How do you distinguish lymphocytes on a smear?
A
Nucleus is round and huge - takes up most of cell!
9
Q
What is a decreased platelet count called?
A
Thombrocytopenia
10
Q
What is a normal platelet count?
A
150 - 400
11
Q
What are bite cells, and what are they associated with?
A
They have “bites” taken out of them due to removal of Heinz bodies
Associated with G6PD deficiency
12
Q
What are schistocytes?
A
A fragmented part of an RBC. Typically irregularly shaped, jagged, and have two pointed ends.
Sometimes referred to as “helmet cells.”
13
Q
What is basophilic stippling?
A
Aggregated rRNA in cytoplasm (looks blue). Caused by lead poisoning and a billion other things.
14
Q
What are Howell-Jolly bodies? What are they caused by?
A
Single, dense, dark blue dot in the RBC cell. This is a nuclear DNA remnant.
Means shit’s gone wrong with your spleen –> splenectomy, functional asplenia, or megaloblastic anemia.
15
Q
What is a Heinz body?
A
Denatured/oxidized hemoglobin attached to inner cell membrane.
Need to stain with supravital dye (crystal violet).
Caused by G6PD deficiency; associated with bite cells.
16
Q
What is a Dohle body?
A
Abnormal WBC inclusion. Pale blue inclusion at the periphery of the cytoplasm. Contents are condensed RNA.
Caused by infection, inflammation, burns, or pregnancy.
17
Q
What is toxic granulation/hypergranularity?
A
Increase in number and presence of granules.
Due to rapid cell division.
Causes: bacterial infection, marrow recovery, G(M)-CSF
18
Q
What are granulocytes?
A
Neutrophils, eosinophils, basophils, and mast cells
Have granules in their cytoplasm
19
Q
What are hypersegmented neutrophils, and what are they associated with?
A
More than 5 lobes in their nucleus
Associated with megaloblastic anemia
20
Q
How does hemoglobin/hematocrit change with age?
A
High at birth, drops from 1-3 months and then decreases more from 3 mo-10 years.
Rises into adulthood, but always less for women than men.
21
Q
What are reticulocytes, how do they develop, and what are their normal numbers?
A
Retics = immature RBCs
3 days in marrow, 1 day in blood
Contain stainable mRNA
Normally 0.4 - 1.7% of 1,000 cells within stain
22
Q
What is the retic index? What is the absolute retic count?
A
Retic count corrected for effect of altered red cell concentration and stress reticulocytes.
Absolute count = % x RBC
23
Q
What is the evidence for hemolysis?
A
↑ bilirubin, ↑ lactic dehydrogenase
↓ haptoglobin, hemosiderin in urine
24
Q
What are the signs and symptoms of anemia?
A
Symptoms: shortness of breath, fatigue, rapid heart rate, dizziness, claudication, angina, pallor
Signs: tachycardia, tachypnea, dyspnea, pallor
25
Where does iron absorption occur?
The duodenum
26
Where is B12 absorbed?
The terminal ileum
27
Where is folate absorbed?
The jejunum
28
What does hepcidin do?
It's produced by the liver, and it ↓ the absorption of iron. Also inhibits ferroportin, which causes ↑ iron retention in macrophages (↑ ferritin)
Synthesis is increased by iron overload or inflammation/infection.
29
What is responsible for iron transport?
Transferrin
30
What is responsible for iron storage?
Ferritin
31
What recycles iron?
Reticuloendothelial system, in spleen
32
How is iron lost?
From exfoliation of skin and mucosal surfaces (GI, skin); in the urine, or with menstruation
33
What are the steps of development of iron deficiency?
1. Plasma levels, ferritin levels normal
2. Iron depletion first from stores --> decreased serum ferritin
3. Iron deficient erythropoiesis --> decreased serum iron
4. Iron deficiency anemia --> depleted from RBCs; microcytic anemia
34
What are the characteristics of iron deficiency?
↓ hemoglobin
↓ cell proliferation
↓ retic count (cell production)
Multiple systems: neuro (mild muscle defect/performance), epithelial (ridges on nails), upper GI (dysphagia), immune dysfunction, and pica!
35
What is dysphagia?
Difficulty swallowing
36
Differential for iron deficiency anemia?
No other hematologic abnormalities --> NO appropriate retic response --> MCV <80 (microcytic anemia)
= iron deficiency anemia
37
What are the causes of iron overload?
↑ iron in diet, ↑ absorption (defect in HLA-H gene), or repeat transfusions
38
What are the consequences of iron overload?
↑ serum iron (sat >50%), ↑ ferritin, ↑ liver iron
Organ damage: cardiac (arrhythmia, failure); liver (dysfunction, failure), endocrine (--> diabetes!)
Treatment: hemochromatosis --> therapeutic phlebotomy
Hemosiderosis --> iron chelators
39
What are the conditions associated with anemia of chronic disease?
1. Chronic infections
2. Chronic inflammatory diseases
3. Malignant diseases
4. Lead intoxication
5. Renal insufficiency
6. Endocrine disorders
40
What is the pathophysiology of anemia of chronic diseases for chronic infection/inflammation?
↑ IL-1 --> ↓ iron + ↓ EPO
| ↑ INFγ --> inhibition erythroid proliferation
41
What happens differently with transferrin in iron deficiency vs. chronic infection/inflammation?
Iron deficiency = transferrin goes up. Chronic inflammation/infection = it stays normal or goes down.
Reason behind this: in iron deficiency, transferrin is trying to compensate for the lack of Fe and sweep up as much as it can. In chronic infection/inflammation, the body thinks that there's a bacterial invader (which requires Fe to grow), so it uses hepcidin to maintain Fe in cells.
42
When should EPO be used for chronic anemia?
(1) when there is an absolute deficiency
| (2) a decrease of EPO out of proportion to the Hct level and for which a response has been documented
43
What is sideroblastic anemia?
Impaired production of protoporphyrin or incorporation of iron.
Smear: ring sideroblasts, iron in mitochondria surrounding the nucleus
44
What is low affinity hemoglobin disease?
Decreased affinity for oxygen --> shift of oxyhemoglobin dissociation curve
Result: mild anemia because of better oxygen delivery
45
Protein calorie malnutrition
Anemia results from lack of protein and calories
| Result: variable anemia, usually normochromic and normocytic
46
What are folic acid and Vit B12 critical for?
The proliferation and maturation of all cells, particularly hematopoietic cells
47
What happens on a cellular level in folate and Vit B12 deficiencies?
Cells increase in size, arrest in S phase mitosis. Vit B12 and folate are required for DNA synthesis.
48
What are the consequences of Vit B12 and folate deficiencies?
Both result in megaloblastic anemias --> large, more immature nuclei; erythroid hyperplasia, hypersegmented nuclei of neutrophils
↑ unconjugated bilirubin & LDH retic
↓ retic count, index
↑ MCV
49
What is the pace in Vit B12 and folate deficiencies?
Folate = rapid (weeks to months); more associated with alcohol abuse & poor nutrition
Vit B12 = more slowly (years); more likely associated with malabsorption
50
What are some of the serious concerns in Vit B12 deficiency?
Neurologic defects :(
Sensory losses first: numbness, tingling. Loss of proprioception. Ataxia, spasticity, gait disturbances. Cerebral symptoms: cognitive and emotional changes.
May be non-reversible :(
51
Where does RBC turnover take place?
Mostly in spleen, small amount intravascularly (10%)
52
What is methemoglobin?
Where the iron in the heme group is in the Fe3+ (ferric) state, not the Fe2+ (ferrous) of normal hemoglobin
53
What happens in intravascular hemolysis?
RBCs release hemoglobin into the circulation. The tetramer form of hemoglobin dissociates into dimers which may immediately bind to haptoglobin.This complex is removed from the circulation by the liver.
Haptoglobin can be overwhelmed, so the iron in hemoglobin can be oxidized to form methemoglobin.
Alternately, methemoglobin or hemoglobin may be filtered by the kidney and appear in the urine.
54
What happens in extravascular hemolysis?
RBC is ingested by macrophages of the RE system. The heme is separated from globin, iron removed and stored in ferritin, and the porphyrin ring converted to bilirubin which is released from the cell.
The bilirubin is conjugated in the liver. After secretion into the biliary tract and small bowel, the glucuronic acid is removed and bilirubin converted into urobilinogen and other water soluble pigments. Urobilinogen may cycle between the gut and liver (entero-hepatic circulation) or excreted by the kidney into the urine.
55
What are some of the lab tests that are changed in RBC hemolysis?
↑ bilirubin (unconjugated)
↓ serum haptoglobin levels (which indicates ↑ binding to hgb)
Detection of hemoglobin in the urine or plasma
↑ metheme or methemalbumin
↑ retic count, hemoglobin (with intravascular)
Release of housekeeping cellular enzymes (SGOT, LDH) from damaged red cells resulting in elevated serum levels may also provide evidence for increased red cell destruction.
56
Hereditary spherocytosis
Characterized by anemia, intermittent jaundice, splenomegaly, and responsiveness to removal of spleen
Loss of membrane --> microspherocyte
EXTRAVASCULAR HEMOLYSIS
Can supplement with folate
57
What are some important complications of hereditary spherocytosis?
(1) Aplastic crises
Shortened red cell survival in the context of viral suppression of marrow production may lead to the rapid onset of severe, life-threatening anemia.
(2) Bilirubin stones
Because of the large amount of bilirubin traversing the biliary tree, bilirubin stones affecting the gall bladder are a common cause of obstruction and cholecystitis requiring cholecystectomy.
58
Pathophys of Glucose-6-Phosphate Dehydrogenase deficiency?
X-linked recessive disorder - provides protection against oxidant stress
Pathophys: premature loss of G-6-PD activity --> oxidant stress --> oxidation of hemoglobin --> denatured globin attaches to membranes (Heinz bodies) --> inability of RBC to deform; trapping in spleen --> extravascular hemolysis
59
What are the clinical features of G-6-PD deficiency?
Intermittent episodes of acute anemia, hyperbilirubinemia, hemolysis, reticulocytosis
Associated with oxidant stress: infection, drug, ingestion of foods (like fava beans)
No specific morphologic feature: may see microspherocytes, "blister" cells, bite cells
60
Autoimmune hemolytic anemia?
Antibodies to universal RBC antigens can cause hemolysis
| Can be intra- or extravascular
61
What is the different between cold and warm autoimmune hemolytic anemia?
COLD (4°C):
IGM antibodies transiently bind to the RBC membrane in cooler areas of the body (fingers, toes, ears, skin) --> in warmer areas, activate complement through the C5-9 attack complex --> creates holes in the plasma membrane --> antibody dissociates itself because of low affinity at higher temperatures --> complement is left to destroy the cell (intravascular hemolysis)
WARM (37°C):
IgG binds RBC with high affinity and have no or poor complement activating capacity --> incite the splenic macrophage to antibody-mediated phagocytosis --> clearance by phagocytosis --> extravascular hemolysis
62
How do you test for antibodies on RBCs?
Antiglobulin or Coombs tests are used to detect IgG and/or complement on the surface of the cell.
The direct antiglobulin test (DAT) evaluates the presence of either IgG or C3d or C4d on the surface of the patient’s red cells by the addition of Coombs reagent, which has antibodies for IgG, C3d and C4d --> causes agglutination
The indirect antiglobulin detects the ability of patient’s serum to bind IgG and/or complement, and then to agglutinize (normal) red blood cells.
63
What are the clinical findings of autoimmune hemolytic anemia?
Acute or chronic onset of anemia (pallor, jaundice, dark urine)
Mild - severe ↓ in Hgb, most cases ↑ retic, ↑ bilirubin, hemoglobinemia/uria
Presence of DAT
May have spherocytes, teardrop, bite cells
64
What does the spleen do?!
Clears intravascular particles (processes blood)
Adaptive immune response: origin of IgM agglutinins
65
Splenectomies - problems? Management?
Problems: overwhelming sepsis, particularly to S. pneumoniae
Management:
(1) vaccination against H. influenzae b, S. pneumoniae, and meningococcal (before splenectomy)
(2) prophylactic antibiotics at least during childhood
(3) see physician immediately for fever >38.5 C
66
What are the blood group O antigens?
RBC--w-x-y-x-Z
```
w = N-acetyl galactosamine
x = D-galactose
z = Fucose
```
Antibodies: anti-A/B
67
What are the blood group A antigens?
RBC-w-x-y-x=W+Z
(both W+Z attached to x)
```
w = N-acetyl galactosamine
x = D-galactose
z = Fucose
```
Antibodies: anti-B
68
What are the blood group B antigens?
RBC-w-x-y-x=X+Z
(both W+Z attached to x)
```
w = N-acetyl galactosamine
x = D-galactose
z = Fucose
```
Antibodies: anti-A
69
What is happening with AB blood?
It's a mixed population of cells of both A and B type
70
What are Rh antigens?
They are three pairs of alleles with a low incidence of cross-over (three alleles inherited as a group). In Caucasian populations, the gene frequencies are D (84%), C (70%), E (30%), ē (97%) and c (80%). Weak expression of D antigen can be mistaken for Rh(D) negative with some standard reagents.
Routine testing is for D (Caucasians are 85% D positive, 15% D negative)
71
What are the pathophysiological defects in HS?
Spectrin, ankyrin, and Band 3 defects (proteins that stabilize the cell membrane of erythrocytes)
72
What is kernicterus?
A bilirubin-induced brain dysfunction. Unconjugated bilirubin from hemolysis can cross the fragile blood-brain barrier in neonates and, because it is water insoluble, bind to lipids in the brain --> damage to CNS
73
What happens in pre-transfusion testing?
Test ABO, Rh(D), antibodies in donor & recipient.
Mix blood together & check for agglutinization.
Add Coombs reagent to look for IgG or complement.
74
What are the 3 types of autoantibody reactions?
Warm IgG scheme, Cold IgM scheme, and Donath Landsteiner scheme
75
What is the warm IgG scheme?
DAT: strong positive for IgG, neg or weakly pos for complement
Temp: 37 max in vitro effect
Antigen specificity: Panagglutinin (reacting to everybody's cells) or Rh-like
Pathophys: Mostly extravascular (macrophages pull IgG out of the circulation)
Prognosis: dependent on underlying disease
Therapy: Block the RE system, immunomodulatory or suppressive approach for severe diseases
76
What is the warm IgM scheme?
DAT: strongly positive for complement
Temperature: 4 C (max)
Antigen specificity: I/i
Pathophysiology: mostly intravascular
Prognosis: May be acute; associated with infections
Therapy: RE blockade NOT LIKELY TO WORK. Immunosuppressive agents. Plasma exchange will work.
77
What is the Donath Landsteiner scheme?
DAT: strongly positive for complement
Temperature: 4 C
Antigen specificity: P
Pathophys: mostly intravascular
Prognosis: usually associated with infections
Therapy: supportive care; keep patient warm. Will resolve with infection.
***Only antibody that will hemolyze RBCs in vitro, not just in vivo***
78
What are the characteristics of whole blood?
Store: 4-6 C
Hct 36-40%
Outdate 35 days
Red cells well maintained. Loss of plt and neutrophil function 24 hours. Loss of clotting factors more slowly
79
What are the characteristics of pack
Store: 4-6 C
Hct 70%
Outdate 35 days (if preservative 42 days)
RBCs are only certified cell. Leuko-depleted units avoid many adverse events.
80
What are the characteristics of fresh frozen plasma?
Essentially acellular = >80% all clotting and anti-coag proteins
Store -18 C up to 1 year
81
What are the characteristics of cryoprecipitate?
Freeze plasma (-80)
Thaw at 4 C, 18 hours centrifuge, and remove cryo-poor plasma
Freeze at -18, 1 year
Contains cryoprecipitable proteins = Factor VIII, Fribrinogen, Fibronectin
82
What are the characteristics of platelet concentrates?
All concentrates stored 22-24 deg with gentle agitation for 5 days
For treatment of bleeding. Luekoreduced products avoid AE; clotting factors degenerate.
83
What are the characteristics of apheresis?
Automated separation process --> all concentrates stored 22-24 deg with gentle agitation for 5 days
Contents: platelets
84
What are the characteristics of granulocyte concentrate?
No storage - keep at RT but give immediately
Hct 3-5%
Contents: granulocytes and platelets
For severe infections in neutropenic patients
85
What causes acute hemolytic transfusion reaction?
Preformed alloantibodies (mostly to ABO) & occasionally autoantibodies cause rapid intravascular hemolysis, DIC, inflammatory mediators, and acute renal failure
Risk is low but mortality is high (up to 40%). Stop the transfusion, maintain renal output with diurectics, treat DIC with heparin
86
Delayed hemolytic transfusion reaction
Formation of alloantibodies after transfusion and resultant destruction of transfused red cells, usually by extravascular hemolysis
Supportive car
87
Febril reactions following tranfusions
Usually caused by leukoagglutinins in recipient cytokines
Supportive
88
Allergic reactions following transfusion
Most causes not identified
Mild reactions: diphehydramine
More severe reactions: epinephrine
89
Graft-vs-host disease
The donor's immune cells attack the recipient's body
90
How long does a monocyte spend in the marrow/vasculature? What does it look like on a smear? What are its functions?
7 days in marrow, 3-5 days in vessels
Has horseshoe-shaped nucleus on smear
Functions: moves to site of infection, processes antigens, removes debris, filter function
91
How long does a neutrophil spend in various places?
10-14 days in marrow
6 hours in peripheral blood
Turnover in tissues in 1-2 days
92
What are neutrophil bands and segs?
```
Bands = immature
Segs = segmented = mature neutrophils
```
93
What are myeloid cells?
Make errrrythang: megakaryocytes, erythrocytes, mast cells, basophils, neutrophils, eosinophils, monocytes.
Basically make everything EXCEPT lymphocytes :)
94
What are mast cells?
Part of immune system; reside in mucosal tissues.
Contain granules of histamine and heparin.
Have roles in allergy, anaphylaxis, wound healing, & defense against pathogens
95
What are the normal neutrophil counts by age?
Newborn (up to one week): <1,500
Ethnic and racial groups: ~900
Lower ANC above 5,000 ft
96
Where should you look when evaluation for neutropenia?
Look at teeth and gums - only place where mucosal barrier is broken - look for inflammation, gingivitis, etc.
Look at lymph nodes, liver, spleen, etc.
97
Kostmann's Syndrome
Apoptosis of myeloid precursors associated with elastase (ELA-2) or HAX-1 gene mutations. Rarely, defect in G-CSF receptor
AD, AR, or S. Rare.
Clinical features: severe neutropenia (<200) early in infancy; myeloid hypoplasia, severe maturation arrest promyelocyte/myelocyte stage
Recurrent purulent infections within first few months. Risk for myelodysplasia or AML.
Treatment: Aggressive treatment of infections; G-CSF daily
98
What is the most common cause of neutropenia?
Infection-associated
Mechanisms:
1. Increased utilization
2. Complement mediated margination
3. Marrow suppression/failure, direct effect
4. Cytokine/chemokine induced margination
5. Antibody production
99
Autoimmune neutropenia
Antibody mediated; increased turnover
May find other hematologic antibodies. Associated with autoimmune disorders (SLE, HIV, etc.)
Variable ANC
Treatment: treat primary autoimmune disorder and/or hematologic abnormalities; G-CSF may be helpful if storage pool depleted
100
Alloimmune Neutropenia
Maternal alloimmunization to neutrophil-specific antigens --> transplacental passage and binding to neonatal neutrophils
Neutropenia usually 2-4 weeks, can be up to 3-4 months. Affected patients may be asymptomatic or may develop skin infections and rare pneumonia, sepsis, or meningitis.
Marrow shows myeloid hyperplasia with maturation arrest at mature precursors --> you don't delete the storage pool
101
What is margination?
The adhesion of white blood cells to the endothelial cells of blood vessels that occurs at the site of an injury during the early phases of inflammation.
102
Cyclic Neutropenia
Mechanism: ELA-2 mutations and apoptosis in precursors and cyclic hematopoiesis
AD, S
Clinical features: recurrent fevers, pharyngitis, aphthous ulcers, gingivitis, periodontitis. Cycles 21 +/- 3 days
ANC <200 for 3-5 days
Bone marrow: myeloid hypoplasia, arrest at myelocyte level during neutropenia
Infections, mouth ulcers during neutropenia; improvement with age
Management: aggressive antibiotic and supportive care for infection; G-CSF daily
103
What is G-CSF?
Granulocyte colony-stimulating factor: a growth factor that stimulates the bone marrow to make more granulocytes and stem cells & release them into the bloodstream
104
Schwachman-Diamond Syndrome
Mechanism: FAS associated apoptosis of marrow precursors; dec of CD34+ cells; marrow stromal defect
AR
Clinical: multi-system disease - neutropenia (90-95%), pancreatic insufficiency, metaphyseal chondrodysplasia, other dysmorphic features
25% develop marrow aplasia, 25% develop MDS/AML
Management: pancreatic enzyme replacement; G-CSF. Aggressive ab & supportive care. BMT for severe complications
105
What is "left shift" in leukocytosis?
A term which describes changes in a normal WBC differential characterized by an INCREASE in neutrophils (segs and bands)
106
How does a neutrophil basically function?
1. Neutrophils are pulled to areas of infection by interacting with endothelial cells
2. ADHESION: mediated by a separate set of adhesion proteins.
3. DIAPEDESIS: passing through the junctions between endothelial cells
4. CHEMOTAXIS: cells move towards the offending organisms, following the trail of chemoattractants (bacterial products, complement products such as C5a, cytokines and chemokines)
5. INGESTION: at the site of infection, the microbe, properly opsonized with C3b or antibody, is enveloped by pseudopods which, like arms, embrace the organism. With fusion of the pseudopods, a phagosome is formed encasing the ingested particle in a small volume.
6. KILLING: Together, reactive oxygen species (ROS) and oxygen independent mechanisms (defensins, lysozyme, cathepsins, proteases) are focused on the phagolysosome and lead to the death and dissolution of the microbe.
107
What is the DHR oxidation test?
Test for neutrophil function: Do the cells actually make superoxide and other oxygen radicals?
You trick cells into taking up dihydrorhodamine (DHR) and then thinking it's a bacteria --> they will cleave it into rhodamine, which is fluorescent.
If you stimulate a patient's cells with PMA --> nothing happens. Missing constituent of neutrophils; cannot break down.
108
Leukocyte Adhesion Deficiency I
NEUTROPHILIA
Recurrent soft tissue infections (skin, mucous membranes), gingivitis, periodontitis, abscesses. Delayed separation of umbilical cord/omphalitis. Poor wound healing.
Decreased adherence to endothelial surface, leading to a defect in movement of neutrophils to infected tissue sites
Need BMT within a year, or will die
Complete or partial deficiency of CD18
AR
109
Chediak-Higashi Syndrome
NEUTROPENIA
Oculocutaneous albinism, nystagmus, photophobia. Recurrent infections of skin, mucous membranes, and respiratory tract by bacteria. Lymphoproliferative phase associated with fever. Neurodegenerative syndrome.
Giant granules in all leukocytes. Abnormal degranulation = large, leaky granules that don't work well. Major defect in movement.
Molecular defect: alterations in membrane fusion with formation of giant, leaky granules. Other abnormalities lead to altered microtubule assembly. CHS1 gene. AR.
110
Myeloperoxidase Deficiency
Generally healthy. Increased fungal infections when associated with diabetes or other systemic diseases.
Partial or complete deficiency of myeloperoxidase. Mild defect in killing bacteria. AR.
111
Chronic Granulomatous Disease (CGD)
Recurrent purulent infections with CATALASE-POSITIVE bacteria and fungi involving skin and mucous membranes. Deep infections of lung, liver, spleen, lymph nodes, and bones.
NEUTROPHILIA. Defect in oxidase enzyme system = no toxic O2 metabolites produced, so absent or reduced ability to kill coagulase positive bacteria and fungi (staph, E. coli, etc.)
112
What are some of the infectious complications of phagocyte disorders?
High rates of bacterial and fungal infections.
Infections with atypical pathogens: Aspergillus pneumonia, Cepacia Burkholderia, S. aureus
113
What is flow cytometry?
A laser-based, biophysical technology employed in cell counting, cell sorting, etc. by suspending cells in a stream of fluid and passing them by an electronic detection apparatus.
114
What is the Coulter principle?
Particles pulled through an orifice, concurrent with an electric current, produce a change in impedance that is proportional to the volume of the particle traversing the orifice.
115
How do you calculate MCV?
HCT / RBC
116
How do you calculate MCH?
HGB / RBC
117
How do you calculate MCHC?
HGB / HCT = MCH / MCV
118
What is the normal range for a WBC?
4.0 - 11.1
119
Where is iron stored in the body?
```
65% - Hemoglobin
13% - Ferritin
12% - Hemosiderin
6% - Myoglobin
0.1% - Transferrin
```
120
What are factors that increase/decrease iron absorption?
```
Intraluminal factors:
Gastric factors (Fe more soluble at low pH)
Presence of protein, aa
Vitamin C
Phytates, oxalates
Amount of iron ingested
```
Extraluminal factors
Erythropoietic activity
121
Where does hematopoiesis occur before birth? During childhood? As an adult?
Before birth: yolk sac, liver, & spleen
During childhood: bone marrow throughout skeletal system
Adult: bone marrow in vertebrae, pelvis, sternum, ribs, and calvarium (skull)
122
Hematopoietic stem cells? Progenitor cells? Precursor cells?
Stem cells: very rare in marrow, unique function of asymmetric cell division (produce 1 stem cell, 1 multipotent progenitor cell)
Progenitor cells: multipotent --> all lymphoid + myeloid lineages. Oligopotent (l or m). Lineage-restricted.
Precursor cells: eosinophil precursor, mast cell precursor, etc. Give rise to mature, functioning cells.
123
The major hematopoietic growth factors (HGFs)
Erythropoietin (EPO) - made by kidney in response to hypoxia, promotes erythropoiesis
Thrombopoietin (TPO) - promotes megakaryopoiesis
Granulocyte-monocyte colony stimulating factor (GM-CSF) - promotes granulopoiesis and monopoiesis
Granulocyte colony stimulating factor (G-CSF) - promotes granulopoiesis
Monocyte colony stimulating factor (M-CSF) - promotes monopoiesis
Interleukin-5 (IL-5) - promotes production of eosinophils
Interleukin-3 (IL-3) - promotes production of basophils
124
Erythropoiesis?
(1) Pronormoblast - deeply blue, 14-20 um, large finely-stippled nucleus
(2) Basophilic Normoblast - coarser chromatin, 10-16
(3) Polychromatophilic Normoblast - 10-12, blue-gray to pink-gray, nucleus round, eccentric, smaller
(4) Orthochromic Normoblast - 8-10, pinker, eccentric nucleus
(5) Reticulocyte - 7-10, pink to pinkish gray, no nucleus
(6) Mature RBC - 7-9, pink, biconcave, etc.
125
What is the general time frame for erythropoiesis?
2-7 days for pronormoblast to mature into orthochromic normoblast
1 more day to extrude nucleus from orthochromic normoblast
2-3 days for reticulocyte to mature in bone marrow
120 days for RBC lifespan
126
What are Auer rods specific for?
Myeloblasts (differentiate into granulocyte cell), but only seen in abnormal conditions
127
Granulopoiesis?
Myeloblast --> promyelocyte --> myelocyte --> metamyelocyte --> band --> seg
128
Time frame for granulopoiesis?
3-6 days in mitotic pool
5-7 days in maturation and storage pools
Leave & enter peripheral blood --> average time spent is 10 hours
129
What is the concept of cellularity in bone marrow?
The "cellularity" of the bone marrow simply means the portion of the marrow that is hematopoietically active; non-hematopoietically active marrow is occupied by stromal elements, which usually is predominantly fat. For example, if half of the marrow is occupied by hematopoietic cells, and half occupied by fat, the cellularity is 50%. The cellularity of the bone marrow decreases with age. Although not entirely accurate, a general rule of thumb is that marrow cellularity should be equal to (more or less) 100 – age.
130
What are some of the major causes of underproduction of anemia?
Chronic infections, chronic inflammatory disease, malignant disease, lead intoxication, renal insufficiency, and endocrine disorders
131
What is the Schilling test?
Test for Vit B12 deficiency
132
What form does iron need to be in to bind oxygen?
Reduced form: Fe2+ (ferrous)
Ferric = Fe3+
133
Deoxygenated hemoglobin is in what conformation?
Taut
| Due to salt bonds, hydrogen bonding, and hydrophobic interactions
134
Hemoglobin is in what conformation when oxygenated?
Relaxed
135
Why does the oxygen binding curve have a sigmoid shape?
Positive cooperativity
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What is P50?
The partial pressure of oxygen at which 50% of hemoglobin is saturated
137
What is the Bohr effect?
At higher pH (in the lungs), oxygen binds more readily
At lower pH (in the tissues), oxygen is released more readily
138
What is the effect of carbon dioxide upon oxygen binding to hemoglobin?
↑ Co2 in blood --> ↓ pH --> ↓ O2 affinity (Bohr effect) --> right shifted curve --> more O2 released to tissues
139
How does temperature affect oxygen binding to hemoglobin?
At higher temperatures, oxygen affinity is decreased and more oxygen is released form the blood to the tissue (right shift)
Temp and O2 affinity inversely related :)
140
What does 2,3-BPG do?
Binds in pocket between beta chains, stabilzing hemoglobin in deoxygenated state (T) --> ↓ O2 affinity --> more oxygen for tissues
141
What is methemoglobinemia?
Fe3+ (ferric iron) cannot carry O2; the curve shifts left
Hemoglobin can carry oxygen effectively but is unable to release to tissues --> P50 goes down --> cyanosis
142
How does a pulse oximeter work?
Photo detector and 2 light-emitting diodes: 660 nm (deoxyhgb is max absorbed) and 940 nm (oxyghemogb is max absorbed)
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What is the molecular basis for sickle cell disease?
Point mutation on beta globin chain: Glu --> Val
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What is the difference between a hemoglobinopathy and a thalassemia?
Thalassemia = decrease in production of normal globin chains
Hemoglobinopathy = structural variants with abnormal function/decreased synthesis OR a thalassemia
145
What are the CBC findings in sickle cell?
↑ retic count, assoc. WBC, platelets
↑ RDW
↑ LDH, bilirubin (hemolysis)
146
Sickle beta-thal
```
Beta+ = some HbA
Beta- = no HbA
```
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SC disease
Sickle + Hemoglobin C disease
HgC = Glu --> Lys
148
Sickle cell trait
Generally, fine = no symptoms, nothing on CBC.
| Rare splenic infarct in white males at high altitude, hematuria, renal medullary carcinoma (VERY rare)
