283 haematology and transfusion Flashcards
(339 cards)
1
Q
components of blood with anticoagulant
A
plasma - 55%
buffy coat
RBCs - 45%
2
Q
plasma pH
A
7
3
Q
whats generally in plasma
A
electrolytes
plasma proteins
various solutes
4
Q
whats in the buffy coat of centrifuged anticoagulant blood
A
WBC
platelets
5
Q
when are haematopoietic precursors seen in blood
A
leukaemia
severe infection or systemic disease
6
Q
precursor to neutrophil stages
A
common erythroid/granulocyte precursor
myeloblast
promyelocyte
myelocyte
metamyelocyte
band cell
neutrolphil
7
Q
precursor to mature erythrocyte stages
A
common erythroid/granulocytic precursor
proerythroblast
early erythroblast
intermediate erythroblast
late erythroblast
polychromatic erythrocyte
mature erythrocyte
8
Q
lifespan of RBC
A
120days
9
Q
RBC structure (5)
A
biconcave
large SA
oxygen transport
haemoglobin
anaerobic metabolism for energy generation
10
Q
diameter of RBC
A
7-8um
11
Q
how many globin protein chains does haemoglobin have
A
4 globin protein
2 beta
2 alpha
12
Q
what happens to the RBCs after120 days
A
phagocytized by macrophages to haem and globin
13
Q
what is heme broken down into
A
bilverdin and then furtherbrokendown intobilirubin
14
Q
what components are needed for erythropoiesis - creation of RBC
A
Fe2+
globin
vit b12
erythropoietin
15
Q
how does bilirubin get to SI
A
transported from macrophage to liver in blood
then to the SI through bile
16
Q
whats needed for bilirubin to convert to urobilinogen
A
bacteria
17
Q
where is urobilinogen transported to next
A
either to stercobilin then faeces
or to kidney via blood and converted to urobilin then excreted via urine
18
Q
how many transmembrane proteins areexpressed in RBC
A
more than 50
in varying abundances
19
Q
what are the transmembrane proteins on RBC prurpose
A
about half define the blood group antigen
other proteins are involved in membrane stability
20
Q
what does the spectrin dimer-dimer and spectrin-actin-protein 4.1R complex allow
A
allow the RBCs to undergo deformation and reformation as they move through circulation
21
Q
what doe a- and b-spectrin form
A
an antiparallel heterodimer
22
Q
on spectrin-actin-protein 4.1R where does ankyrin bind
A
to the head end of the b-spectrin dimer
makes part of ankyrin complex
allowing normal membrane cohesion
23
Q
What is going on in the tail section of the spectrin-actin-protein 4.1R junctional complex
A
spectrin dimer binds to actin filaments
which are capped at opposite ends by adducin and tropomodulin
actin binds to protein 4.1R and the complex is anchored to transmembrane proteins
24
Q
isocytosis definition
A
cells have the same size
25
anisocytosis definition
cells have unequal size
26
microcytic definition
cells are smaller than usual
27
macrocytic definition
cells are larger than usual
28
poikilocytosis definition
cells have an atypical shape
29
hypochromic definition
cells don't stain well
30
macrocyte abnormality causes
liver disease
alcoholism
oval in megaloblastic anaemia
31
target cell abnormality causes
iron deficiency
liver disease
haemoglobinopathies
post-splenectomy
32
stomatocyte are seen in what
liver disease
alcoholism
33
where are pencil RBC seen
iron deficiency
34
where are ecchinocyte RBCs seen
liver disease
post-splenectomy
35
what are acanthocyte seen in
liver disease
abetalipo-proteinaemia
renal failure
36
what are microsphercyte RBCs seen in
hereditary spherocytosis
autoimmune haemolytic anaemia
septicaemia
37
what are fragment RBCs seen in
DIC
microangiopathy
HUS
TTP
burns
cardiac valves
38
what are eliptocyte RBCs seen in
hereditary eliptocytosis
39
what are tear drop poikilocyte rbcs seen in
myelofibrosis
extramedullary haemopoiesis
40
what are basket cell rbcs seen in
oxidant damage
e.g. G6PD deficiency
41
what are sickle cell rbcs seen in
sickle cell anaemia
42
what are microcyte rbcs seen in
iron deficienct
haemoglobinopathy
43
what does hematocrit blood test measure
ratio of vol of rbcs to total blood vol
44
what does mean corpuscular volume measure
size of RBC
45
what does mean corpuscular haemoglobin measure
amount of Hb/cell
46
what does mean corpuscular haemoglobin concentration measure
amount of Hb/vol of RBCs (% of RBCs that contain Hb
47
how many major blood group antigens are there
8 that are either sugars (ABO, Hh) or proteins (Rh, Diego, MNS, Kell, Kidd, Duffy)
48
what are ABO antigens encoded from
the ABO gene
which has 3 alleles A B O
49
how many possible genotypes are there for ABO blood types
6
50
how many phenotypes are possible in A B O bloodgroups
4
as o allele is recessive
51
if someone has type A blood what antigen does the RBC have
A antigen
52
what does the H gene encode for
fucosyltransferase enzyme
which adds a fucose onto terminal galactose of an oligosaccharide chain = H antigen
53
how is the A antigen produced
A allele encodes a glycosyltransferase that adds an N-acetylgalactosamine to the terminal galactose = A antigen
54
how is B antigen produced
B allele encodes a glycosyltransferase that adds a D-galactose to the terminal galactose= B antigen
55
how is no AB antigens formed
the O allele encodes anon-functional glycosyltransferase so no additions are made to the terminal galactose = produces no AB antigens
56
how many different Rh antigens are there and which are most important
49 different antigens
D, C, E, c and e are most important
57
which 2 genes encode for Rh antigen
RHD
RHCE
(ch1)
58
what happens if RhD gene is present
RhD+
ifRhD gene is deleted = RhD-
59
which of the blood group antigens produces the 2nd strongest immune response
Rh antigen
60
whats the universal donor blood group
O
61
whats the universal recipient blood group
AB
62
what does alternative splicing of RHCE give rise too
C
c
E
e
63
ABO and RhD blood typing
mix washed RBCs with antibodies against A B and D antigens
if corresponding antigen is present the antibody will bind and the RBCs will clump together
64
blood testing before transfusion method
gel-based tech- gel has antibodys
add washed RBC to microcolumn
centrifuge
agglutinated cells stay on top of gel (+ reaction)
non-agglutinated cells pass through gel (- reaction)
other methods include crossmatching (mix with donor cells), patient serum tested for antibodies
65
ABO blood groups have naturally occurring antibodies against other
ABO antigens
true or false
true
66
RhD- produces naturally occurring antibodies against RhD
true or false
false
67
how do immune antibodies to RhD develop
Anti RhD IgG can develop by exposure of RhD- recipient to RhD+ donor blood
68
haemolytic disease of the newborn (HDN)
RhD incompatibility between mother and child- resulting in fetal anaemia and/or death
Rh+ father and Rh- mother
first Rh+ fetus- antigens from fetus can enter mothers blood in delivery so mother develops anti-Rh antibodies
so when pregnant with 2nd Rh+ fetus- her antibodies will cross placenta and attack fetal RBCs
69
how to prevent HDN
- inject with anti-RhD antibodies within 72hrs of birth
- antibody removes foetal RhD+ RBCs from maternal circulation
- no anti-RhD antibodies are made by mother
so foetal RBC not destroyed
also routine antenatal anti-D prophylaxis (RAADP), 1 or 2 dose injection of anti-RhD during week 28-30 of pregnancy
70
whos eligable for blood donation
healthy
unpaid
volunteers
71
who cannot donate blood
if you have had
chronic disease
blood transfusion
pregnant
current infection
IV drug use and others
had piercing, tattoo, acupuncture in last 4months
sexual encounter for sex worker or male who have sex with males in last 3 months
live vaccine wait 4-8 weeks
defer based on travel history
72
blood transfusion history
whole blood transfusions first attempted in 1600 and the norm until 1970s
after then component blood was used exclusively for reducing waste, improving storage and tailor treatment
73
whats added to blood transfusion blood once collected
anticoagulant (CDP- citrate, phosphate, dextrose)
the citrate binds calcium=anticoag
dextrose-RBCs stay metabolically active
74
leucodepletion
filters blood after collection to remove majority of WBC
<1 x 10^6 = leucodepleted
it helps prevent immune reaction against donor WBC and febrile reactions and transmission of CMV and nvCJD
75
what tests are done on donated blood - mandatory
hep B and c
HIV
human T cell lymphotropic virus (increased risk of leukaemia development)
syphilis
76
what special circumstance test are done on blood donations
cytomegalovirus (CMV)
malarial antibodies
west nile virus antibodies
trypanosoma cruzi antibodies
77
can you test for prions in blood donations
no
78
what are blood donations used for
packed red cells
frsh frozen plasma (FFP) and cryoprecipitate
platelets
79
what are packed red cells
plasma depleted red cells
1 unit of packed red cells= 220ml red blood cells
80
how quick must packed red cell transfusion be completed
within 4 hours
81
what are packed red cell transfusion used for
-replacing blood loss- trauma, surgery, haemorrhage
- correct anaemia- marrow failure(e.g. leukaemia), haemoglobinopathies(e.g. thalassemia), chronic disorders (malignancy),sever haemolysis (HDN)
82
how long can packed red cells be stored for and at what temp
4-6 c for up to 35 days
83
fresh frozen plasma (FFP)
main use for replacement of coagulationfactors
84
cryoprecipitate
made from FFP by thawing slowly at 4c
precipitate rich in fibrinogen and von willebrande factor and factor vIII
use in DIC
85
platelets (blood transfusion)
use in thrombocytopenia (low platelets count)
platelet function problems, bleeding or risk of bleeding
platelets always stored at rtp
86
haemolytic transfusion reactions
early
chills, dizzy, fever, pain
risk of death = 10%
wrong blood supplied
stop transfusion and treat symptoms
87
febrile reactions
early
fevers, rigors
causes- cytokines in donor blood, recipient antibodies react to leukocytes in donor blood
treat with leucodepletion
88
transfusion-related acute lung injury (TRALI)
early
respiratory distress
causes- large amount of plasma donated, donor antibodies attack recipients white cells
treatment- oxygen, supplementation. fluids and drugs to maintain BP
89
transfusion-associated graft-versus-host
late reaction
fever, rash, enlarged liver, diarrhoea, risk of death= 80-90%
causes - donor lymphocytes react against recipient tissue (e.g. immunocompromised patient)
no direct treatment just support
90
infection - blood transfusion complication
late reaction
symptoms depend on infectious agent
caused by incomplete or incorrect screening
treatment depends on disease
91
iron overload- transfusion complication
late reaction
growth retardation, liver fibrosis and cancer, heart failure
caused by repeat transfusion, iron deposition in organs and glands
treated with chelation therapy
92
3 components of haemostasis
vessel spasm
platelet adhesion
blood clotting
93
what does vessel spasm in haemostasis mean
it reduces blood flow
initiated by pain receptors and aided by thromboxane A2 and serotonin
94
haemostasis
sequence of events to stop bleeding to prevent a haemorrhage
95
how long do platelets last in circulation
7-10 days
96
what do the a granules in platelets contain
firbinogen
factor v
von willebrand factor (vWF)
fibronectin
97
what do electron dense granules in platelets contain
ADP
calcium
serotonin
98
where are a and electron granules found in platelets
in the cytoplasm
99
what are platelets
pinched off from megakaryocytes into the circulation
100
platelet adhesion in the formation of a plug
endothelial cells are anchored to vessel wall via basement membrane (basal lamina)
the BM is made up of a mesh of proteins including collagen
damage to this endothelium exposes the collagen to platelets and soluble vWF in the blood
101
platelet adhesion reaction
GPIa/IIa receptors on platelet surface attaches to exposed collagen
vWF in blood attaches to collagen
GPIb/IX/V binds to vWF= induces exposure GPIIb/IIIa complex which also attaches to vWF but with much higher affinity, holds the vWF tightly
102
what happens once platelets bind
changes shape increasing SA
activated ones then release granules contents
thrombin produced via coagulation cascade
103
what happens once thrombin is produced from coagulation cascade in platelet activaiton
recruitment and activation of naive platelets
104
how are platelets held together
via fibrinogen and vWF bridges that are formed by binding GPIIB/IIIa on platelets
105
platelet plug formation summary (8 points)
Exposed subendothelial matrix coated with vWF
Platelets stick to vWF via GPIb/IX/V complex
The interaction of vWF and GPIb/IX/V exposes and activates GPIIb/IIIa
GPIa/IIa and GP VI bind directly to collagen which activates platelets
Platelet shape change – pseudopodia and increase in surface area
Platelet activation leads to granule secretion
ADP and Thromboxane A2 (TXA2) release causes further platelet activation = amplification
GPIIb/IIIa interacts with vWF and with fibrinogen leading to platelet
106
what lab test for platelet function
bleeding time
PFA-100 (platelet function analysis)
light transmission aggregometry
107
bleeding time lab test
incision in forearm
time for bleeding to stop <9mins
tests platelet function
108
PFA-100 lab test
tests platelet function
blood passed through agonist-coated hole
measure blocking time
109
light transmission aggregometry lab test
tests for platelet function
add platelet agonist to blood
measure light transmission through the blood = increases as platelets aggregate
110
coagulation tests on patient plasma (3)
thrombin time (TT)
prothrombin time (PT)
activated partial thromboplastin time (APTT)
111
activated partial thromboplastin time test for which pathway
intrinsic and common pathway
112
APTT test reagents added and what it measures
measures clotting time
reagents= phospholipid/ kaolin/ calcium
113
what does it mean if APTT is elevated
deficit in these factors - XII, XI, IX, VIII, X, V, II, I
vit k deficiency
liver disease
von willebrand disease (Carries VIII)
114
what pathways does prothrombin time test for
extrinsic and common pathways
115
what does PT measure and what are the reagents. and the INR equation
measures clotting time
reagents= tissue factor/calcium
international normalised rate= PT of individual/ PT normal population
116
if PT is elevated what does this mean
deficit in these factors= VII, X, V, II, I
vit K deficiency
liver disease
117
what pathway does thrombin time test for
common pathway
118
what does thrombin time test and what are the reagents
measures clotting time
reagents: thrombin, calcium
119
what does it mean if TT is elevated
low fibrinogen (e.g. DIC)
etc
120
wheres teh defect if only PT elevated
defect in extrinsic pathway
121
wheres the defect if only APTT elevated
defect in intrinsic pathway
122
wheres the defect if both PT and APTT raised
defect in common pathway
123
whats fibrinolysis
breakdown of fibrin clot
124
how is plasminogen converted to plasmin to break down fibrin clot
tissue plasminogen activator (tPA) is released from endothelial cells
factor XIIa in the platelets
inactivated plasminogen is incorporated into clot
125
fibrin degradation products (FDPs)
anticoagulant interferes with fibrin polymerisation
present in FFP used to treat disseminated intravascular coagulation (DIC)
126
examples of medications to prevent clotting
anticoagulants
heparin- activates antithrombin
warfarin- vit k antagonist,vit k needed for activation of II, VII, IX and X
aspirin- inhibits formation of thromboxane A2 (released from platelets)
127
examples of medications to dissolve a clot
thrombolytic agents, convert plasminogen to plasmin
- streptokinase
tissue plasminogen activator (tPA)
128
thrombocytopenia is disease with a lack of what
platelets
idiopathic thrombocytopenia (ITP)
129
are bernard soulier disease and glanzmans thrombosthenia inherited or acquired
inherited
disorder of platelet function
130
are the disorders of platelet function, aspirin, renal failure, haematological disease inherited or acquired
acquired
131
what is hereditary haemorrhagic telangiectasia (HHHT and inherited connective tissue disorder
they are vascular inherited bleeding disorders (purpuras)
132
what is Henoch-Schonlein purpura, scury and senile purpura
they are acquired vascular bleeding disorders (purpuras)
133
causes of thrombocytopenia
failure in production of e.g. marrow disease
increase in destruction- immune mediated
abnormal distribution- increased pooling in the spleen
dilution- massive transfusion
134
platelet count in thrombocytopenia
fewer than 100x10^9/L`
normal range = 140-360 x10^9/L
135
symptoms of thrombocytopenia
spontaneous bleeding from mucous membrane
e.g gums/nose
136
whats purpura
a rash of purple spots under the skin caused by vessel haemorrhage
137
symptoms of autoimmune (idiopathic) thrombocytopenia purpura (ITP)
petechiae/ pupura, nose bleeds
138
causes of ITP
development of antibodies against platelet self antigens
platelets are destroyedin spleen and liver
139
acute vs chronic ITP
acute- children post viral infection or vaccine
chronic- often antibodies to IIb/IIa. platelets destroyed in spleen and liver
140
Bernard-Soulier disease
deficiency of GP Ib-IX-V
loss of platelet adhesion
symptoms - bleeding gums, bruising, menorrhagia
141
Glanzamanns thrombasthenia
loss of function of GP IIB/IIa
loss of platelet aggregation
symptoms- bleeding gums, bruising, menorrhagia
142
renal failure and platelet disorder
uraemia- high levels of creatinine and urea in blood
results in abnormal platelet adhesion, activation and aggregation
symptoms - bleeding or bruising more easily
143
haematological disease and disorders of platelet function
abnormal bone marrow function (e.g.leukaemia)
anaemias
complications from chemo or transfusions
symptoms- bleeding or bruising more easily
144
mechanism of action of aspirin
platelet activation needs production of thromoxane A2 which is made via phospholipid pathway
aspirin irreversibly inhibits cyclooxygenase 1
preventing conversion of arachidonic acid to endoperoxides and thromboxane A2
platelet aggregation is inhibited for lifetime of platelet
145
symptoms of hereditary haemorrhagic telangiectasia
small blood vessel swellings. telangiectasia on skin, mucous membrane, internal organs, GI haemorrhage
146
what is hereditary haemorrhagic telangiectasia (HHT)
autosomal dominant mutation in genes associated with angiogenesis
it increases vessel friability = solid substances break into smaller pieces under contact
147
inherited connective tissue disorder
rare
lack of connective tissue support for blood vessels or abnormal collagen= disrupted vessel strucutre and ineffective platelet syndrome
148
symptoms of inherited connective tissue disorders
easy bleeding
149
acquired Henoch-Schonlein purpura
systematic vasculitis resulting in blood vessel bursting
IgA attacks blood vessels, often after a respiratory infection
affects skin, joints, bowels, kidneys
symptoms- raised rash, joint pain, blood in urine
150
scurvy as an acquired vascular bleeding disorder
vitamin c deficiency (needed for collagen production)
symptoms - petechiae, poor wound healing
151
senile purpura
acquired vascular bleeding disorder
due to tissue atrophy, loss of connective tissue e.g. collagen
symptoms - skin bruising in elderly
152
what factor is haemophilia A a deficiency of
factor VIII (antihaemophiliac factor)
153
haemophilia A genetics
x-linked
recessive
often family history
but 1/3 cases are from spontaneous mutations
154
how many people does haemophilia A affect
30-100 million people
most common haemophilia
155
symptoms of haemophilia A
excessive bruising and bleeding during operations
prolonged APTT test (intrinsic pathway)
bleeding timeand PT/INR normal
156
haemophilia B genetics
x-linked
recessive
157
what factor deficiency is haemophilia B
factor IX
christmas factor deficiency
158
how many people does haemophilia B affect
3-4 / 100 000 people
159
symptoms of haemophilia B
same as A
excessive bleeding and bruising
prolonged APTT test (intrinsic pathway)
bleeding time and PT/INR are normal
160
what does vWF promote
adhesion of platelets to subendothelial matric and carries factor VIII
161
symptoms of von willebrands disease (vWD)
spontaneous bleeding
e.g. nose bleeds, menorrhagia
162
what is vWD characterised by
low amounts of factor VIII=abnormal platelet adhesion
prolonged APTT
PT/INR normal
increased bleeding time (platelet aggregation prolonged)
163
what is thrombophilia
too much factor II
164
disseminated intravascular accumulation
widespread intravascular fibrin formation = coagulation factors and platelets used up
165
symptoms of disseminated intravascular accumulation
bleeding
large vessel thrombosis
haemorrhage tissue necrosis
166
causes of disseminated intravascular accumulation
widespread endothelial damage
e.g. incompatible blood transfusion, septicaemia, viral infection, malignancy, surgery, burns etc
167
FDPs
fibrin degradation products have anticoagulant activity = risk of severe bleeding
seen in disseminated intravascular accumulation
167
what do the tests look like in disseminated intravascular accumulation
APTT, PT/INR and TT increased
168
what factors need vitamin K to form
II, VII, IX, X
169
causes of vitamin K deficiency
malabsorption
malnourishment
warfarin therapy (inhibits vit K)
170
haemorrhagic disease of the newborn
newborns have sterile gut (no intestinal flora)
breast milk is low in vit K
liver cells immature
symptoms- easy bruising, blood in stool or urine
vitamin Know given to newborns via subcutaneous injection
171
liver disease as as an acquired coagulation disorder
liver makes coagulation factors, thrombopoietin and clears FDPs
liver disease has fewer coagulation factors, FDPs not cleared, fewer platelets made, bile obstruction- lack of vit K uptake from gut
172
acquired haemophilia
autoimmune disorder
antibodies made to coagulation factors e.g. factors VIII
symptoms- excessive bruising and bleeding
increased APTT and PT/INR
increased bleeding time
173
thrombophilia
increase in thrombin formation or impaired fibrin breakdown
causes
oestrogen therapy- antithrombin deficiency
inflamm- protein C reduction
malignancy- Xa increase
symptoms - swelling, pain, leg cramps, skin discoloration
174
3 types of microcytic, hypochronic anaemia
iron deficiency
chronic disease
thalassemias
175
symptoms and indicators of iron deficiency anaemia
fatigue
weakness
heavy periods (menorrhagia)
change in bowel habit
176
in iron deficiency anaemia are MCH, MVC, serum ferritin and serum iron high or low
MCH, MVC, serum ferritin are low
serum iron (bound to transferrin)= low
177
in iron deficiency anaemia is the TIBC high or low
TIBC- total iron binding capacity = maximum Fe which could be bound to transferring is high
178
iron cycle components
RBCs
macrophages in spleen
serum transferrin-Fe to and from liver and excreted into gut
erythroid bone marrow
back to RBCs
179
blood films in iron deficiency anaemia
dimorphic blood film
responding to iron therapy or post-transfusion
180
what chronic diseases cause anaemia
chronic inflamm diseases like infectious pneumonia and TB, and non-infectious like chrons, arthritis
malignancy
181
why do chronic inflamm disease patients develop anaemia
cytokines IL1 and TNFalpha being produced
these have negative effectonerythropoiesis = RBCs not replaced
182
how does megaloblastic anaemia happen
folate and vit B12 needed for dTTP
deficiency in either = less dTTP = delayed DNA synthesis
so RBC nucleus maturation delayed
183
how can u see if RBC have megaloblastic anaemia
immature RBC have less than normal number of cell divisions. chromatin abnormal (salami appearance)
red cells enlarged (macrocytosis)
oval
184
causes of megaloblastic anaemia
pernicious anaemia
folate deficiency
185
pernicious anaemia
autoantibodies IgG to gastric parietal cells which make intrinsic factor needed to combine with B12 before absorption
megaloblastic anaemia
186
folate deficiency
malabsorption
increased demand
dietary deficiency
leads to megaloblastic anaemia
187
2types of haemolytic aneamias
inherited -problems intrinsic to the rbc
acquired - autoimmune, alloimmune
188
where are the abnormalitys location in inherited haemolytic anaemias
haemoglobin
RBC membrane
RBC metabolism
189
what causes abnormalities of haemoglobin
haemoglobinopathies
leads to inherited haemolytic anaemia
190
what causes abnormalities of RBC membrane
hereditary spherocytosis
hereditary elliptocytosis
leads to inherited haemolytic anaemias
191
what causes abnormalities in RBC metabolism
glucose 6-phosphate dehydrogenase deficiency
pyruvate kinase (PK) deficiency
leads to inherited haemolytic anaemias
192
hereditary spherocytosis, how do RBCs look
small
heavy stain
rbc membrane problem
(spectrin, ankyrin...)
inherited haemolytic anaemia
193
hereditary elliptocytosis,
RBC membrane problem
often spectrin
194
components of RBC membrane
phospholipids
band 3 protein
ankyrin
glycophorins A, C and B
spectrin
holesterol
actin (attaches)
195
G6PD deficiency
abnormality in RBC metabolism
inherited haemolytic anaemia
cell not protected from oxidant stress
196
pyruvate kinase deficiency
abnormality in RBC metabolism
inherited haemolytic anaemia
cells cant make ATP and become rigid
197
autoimmune haemolytic anaemia (AIHA)
autoantibodies against RBC antigens
cold AIHA blood film- agglutination of rbc in peripheral circulation - cyanosis
198
coombs test
antibodies detection on rbc surface
direct antiglobulin test
anti human globulin added
agglutinationof rbc
199
alloimmune haemolytic anaemia examples
ABO incompatible blood transfusion
haemolytic disease of the newborn
200
what percentage of a rbcs weight is Hb
33%
201
how many Hb molecules per RBC
640million
202
whats the haemoglobin in an adult vs fetus
adult- HbA
fetus- a2v2 (HbF)
203
how many introns and exons are in globin genes
3 exons
2 introns
204
embryo chains in globin
: ζ chain substitutes for chain and γ or ε chain substitute for β chain.
205
3-6month of life globin chains
switch from γ to β chain i.e. HbF (2γ2) to HbA (2β2)
206
what does haemoglobinopathies refer to
abnormalities of haemoglobin
reduced rate of synthesis of normal a or b globins
synthesis of abnormal haemoglobins- sickle cell anaemia
207
what location is sickle cell anaemia seen in
central africa
208
what location is HbC seen in
west africa
liberia, sierra leone etc
209
what synthesis is reduced in a-Thalassaemia
a-globin synthesis
210
wheres HbE commonly found
south east asia
indonesia
malyasia
211
where is HbD commonly found
north west india
212
where is the mutation in a-thalassaemia
usually in promotor region or frame shift
results in no gene product
213
does a-thalassaemia have symptoms
trait is symptomless
but increased RBC
decreased MCH
decreased MCV
214
how many alpha globin genes are deleted/dysfunctional in a-thalassaemia
3
215
what is seen when you stain a-thalassaemia Hb-H cells
stain with methylene blue or brilliant cresyl-blue
reveals 'golf ball' cells
216
whats used in haemoglobinopathies for diagnosis
high performance liquid chromatography (HPLC)
different haemoglobin migrate at different rates
fast
automated
accurate
217
can you survive if all 4 alpha globin genes are deleted in a-thalassaemia
no
hydrops fetalis
incompatible with life beyond fetal stage as HbF, HbA, HbA2 all require a globin chains
218
what type of mutation is b-thalassaemia normally
point mutation
219
what is mutated in b-thalassaemia
absent beta chain (B0)or reduced production (b+)
220
is b-thalassaemia fatal
y and δ chain still produced so loss of b chain not fatal
221
in b-thalassaemia is there excess a globin
yes theres excess precipitate in erythroblasts - leads to haemolysis and ineffective RBC production
greater excess of a chains, greatest anaemia
222
a way of diagnosing b-thalassaemia
via cellulse acetate electrophoresis
223
treatment for b-thalassaemia major
stem cell transplantation
drugs to stimulate HbF
gene therapy
224
lab tests for b-thalassaemia major
absence or almost absent HbA
increase in HbF and HbA2
blood smear- hypochromic, microcytic, nuceated RBC, target cells
hair on end skull appearance
225
b-thalassaemia major
severe anaemia 3-6months old
hepatosplenomegaly - increase in RBC destruction
expansion of bone marrow and bones
regular blood transfusion needed
splenectomy may reduceneed
226
b-thalassaemia intermedia
moderate anaemia - homozygous mild B+ thalassaemia or heterzygous ver sever b defect or mixture of thalassaemias
presentation at 2-5yrs
blood smear- hypochromic, microcytic, RBC raised
Hb reduced possible boen deformity
regular transfusions not needed
227
b-thalassaemia minor
a trait
heterozygotes B+ or B0
usually asymptomatic
blood smear- hypochromic, microcytic, RBC raised
228
wheres the amino acid substitution in sickle cell disease
position 6 in beta chain - alteration of glutamic acid (acidic) to valine (hydrophobic)
abnormal b chain called Bs
HbS= a2Bs
229
homozygote vs heterozygote sickle cell anaemia
HbSS- severe anaemia
HbAS- trait- no anaemia,normal blood smear, protection from malaria
230
how to diagnose of sickle cell
sickle solubility test
cheap and rapid
HbS insoluble when deozygenated in high conc phosphate buffer
HbS on right
or
high performance liquid chromatography (HPLC)
231
sickle cell anaemia blood film
HbS polymerises into fibres causing sickling of RBC
block small vessels causing pain
can lead to death or tissue(infarction)
vaso-occulusion in small boneslike fingers can affect growth
if in brain = stroke
232
DNA damage definition
a change to the regular chemical structure of the DNA double helix
233
what happens if dna damage isnt detected
mutation
damage is replicated
234
e.g. of dna damage
A break in the phosphodiester backbone of the polynucleotide chain – strand break – either single or double break
Loss of a base from the deoxyribose sugar
Alteration to the structure of a base
Non-complementary bases in the double helix (mismatched base pairs)- due to replication errors
235
mutation definition
a permanent heritable change in the sequence of an organisms genome
236
can dna mutations be fixed
no
the damage can but not the mutation
237
point mutation
alteration
insertion
deleton
of 1 or few bases
238
chromosome mutations
rearrangmetn
deletion
instertion
239
transition vs transversion mutation
transition:
-purine to purine or pyrimidine to pyrimidine
transversion:
- purine to pyrimidine or pyrimidine to purine
240
nonsense mutation
coding codon to a stop codon
241
missense mutation
chemically changing AA
2 types
conservative - + AA to +AA, might not be that big of deal
non-conservative= basic to polar AA
242
forward mutation
wild type active transform to mutant defective
243
reverse (reversion) mutations
mutant defective to wild type active
244
true reversion
restores sequence to code for the wild type AA in affected protein
245
partial reversion
changes sequence at site of original mutation to some other AA that fully or partially restores protein function
246
suppressor mutation
changes sequence at a different location from original mutation in way that compensates for original mutation
Intragenic- in same gene but different site-still restores protein function
Intergenic- mutation of different genes
247
are most mutations spontaneous
yes
arise without exposure to exogenous agents
248
prokaryotes spontaneous mutation rate
~10-9/nt/generation (or ~10-6/typical 1 kb gene/generation) – ie for a 1 kb gene 1 mutation in ~1 million cell divisions
249
how easy to measure spontaneous mutation rate in human
very hard
varies accross diff sequence classes
Germline nucleotide substitution 10-8/nt/generation
In humans ~30 new mutations in 3 Gb haploid genome inherited from each parent
Somatic mutation rate is higher and varies in different tissues
250
are mutations adaptive or random
random
adaptive organisms direct mutations to adapt to a particular environment
random changes can just happen to be adaptive occasionally
251
how do spontaneous mutations arise
replication containing premutagenic damage caused by
- dna rep errors like nucleotide or template tautomerism(mismatches), replication damage
- endogenous dna damage- base deamination, loss, modification as a result of exposure to metabolic products
252
whats the overall rate of mis incorporated nucleotides not repaired
1in 10^9-10^10
253
what are non-watson-crick base-pairs called
tautomer's
like A-C and G-T
254
where does slippage usually occur in dna
repeat area normally
either looping in new strand or template strand
255
whats depurination
glycosidic bond between base and phosphate broken
leaves apurinic site with no base to deoxyribose (premutagenic lesion)
AP sites result in random base substitution or baseskipping
depurination more likely too occur than depyrimidination
256
premutagenic lesion
apurinic site (AP) with no base attached to deoxyribose
257
is depurination or depyrimidination more common
depurination
as easier to break h bonds
258
what does deamination of cytosine result in
uracil produced
not normally present in dna
if on 5MeC it produces a GT base pair
makes it a hotspot
259
alkylation of dna
alkyl groups can be added to places like s-adenosylmethionine
able to produce O6-methylguanine
h bond donor changed for acceptor - wobble base pair
260
oxidative dna damage
attack reactive o2 species (ROS) O2, H2O2, OH on e.g. guanine
high mutation rate mitochondrial genomes
damaged bases may be mutagenic or lead to strand breakage/ replication block
261
exogenous sources of dna damage
chemical mutagens liek base analogs, base modifying agents, intercalating agents
physical mutagens - ionising radiation, uv
262
base analogues and how cause mutation in dna
forms unusual tautomeric form
e.g. 5-bromouracil actually stable
geneticists use this to induce mutations, transitions mutations
increases rate of mutatons occuring
263
nitrous acid on dna
deaminates
able to promote deamination
Deam of methyl groups in G
Deam of amino groups in c and a?
264
base-modifying agents on dna
hydroxylamine hydroxylates
MMS methylates
deliberatly put on cells to induce mutation
introduces methyl groups to dna
265
what base-modifying agent needs to be metabolically activated first
polycyclic aromatic hydrocarbons
like benzo[a]pyrene which are metabolised by cytochrome p450 enzymes
as apoxyl grp which is very reactive so reacts with dna easily
266
sources of benzopyrene
cigarettes
charred meats
exhausts
chimney soot- first eg of public anti cancer intervention
267
what do intercalating agents induce in dna
induce frame shift mutations
268
what do intercalating agents do
flat planar structure than insert in minor groove between bps and stack
partially unwind dna inducing replication errors like insertions and deletions
269
whats leukaemia a cancer of
the blood
a group of closely related malignant conditions affecting the immature blood-forming cells in the bone marrow
270
what is lymphoma a cancer of
lymphatic tissues
271
what is multiple myeloma
cancer that affects plasma B cells
272
whats myelodysplastic syndromes
a group of disease in which production blood cells is severly disrupted
273
whats myeloproliferative disorder
group of conditions where theres an overproduction of 1 or more type of blood cell
274
symptoms of leukaemia
anaemia- fatigue, breathlessness, pale
thrombocytopenia (low platelets)- bruising, bleeding mucous membranes, heavy period
low WBC
persistent infectiosn
fever
night sweats
abdominal discomfort
275
cause of leukaemia
normally no familial pattern
childhood leukaemia linked to mothers drinking/smoking
increased risk with age
some forms linked to viruses(EBV
276
how much has laeukaemia incidence increased by
13% between 193-95 and 2016018
277
ways in which leukaemia can be diagnosed (5)
blood count
blood smear
bone marrow aspirate/biopsy)
chromosome analysis (karyotype/cytogenetics)
diagnostic imaging - like bone marrow
278
whats FAB - french american british classification system
series of classifications of haematologic diseases
based on:
- dysmyelopoiesis presence- cytopenia presence in blood and dysplastic cells in 1+ haematologic cell lines
- quantification of myeloblasts and erythroblasts
279
is acute leukaemia or chronic more aggresive
acute is aggressive
chronic less aggresive
280
whats acute leukaemia generally due to
blockage in differentiation
lack of mature cell production
281
whats chronic leukaemia generally due to
overproduction of mature cells
282
types of leukaemia (4)
acute
chronic
lymphoid
myeloid
283
risk factors for acute lymphoblastic leukaemia (ALL)
- ionising radiation - include chemo
- pesticide exposure
genetic conditions like down syndrome, AT
- weakened immune system
284
whats the cure rate of acute lymphoblastic leukaemia in children
90%
285
who most likely to have ALL
cancer of childhood
peak incidence is 1-4yrs
286
whats acute lymphoblastic leukaemia neoplasm of what precursor
precursor b or T lymphoid cells
287
what does ALL blood film look like
lymphocytesare immature
large nucleus
little cytoplasm
288
whats the most common acute leukaemia in adults
acute myeloid leukaemia (AML)
289
what is acute myeloid leukaemias neoplasm of what
neoplasm of myeloid stem cells or myeloid blasts
290
cure rate for AML
30%
only in those suitable for high dose induction chemo
palliate in elderly cases (normaly)
291
whats the FAB classification for AML
M0 - M8
(cytogenic classification too)
292
what does the blood film for AML look like
very large immature myeloblasts with many nucleoli
distinguished by linear 'auer rod' composed of crystalised granules (a little line thats defined)
293
FAB classification for acute promyelocytic leukaemia
M3
hypergranular
promyelocytic
294
cytogenic classification of acute promyelocytic leukaemia
15;17
295
whats the problem in acute promyelocytic leukaemia
coagulation problem
296
whats the cure rate for acute promyelocytic leukaemia
90%
297
treatment for acute promyelocytic leukaemia
all-trans retinoic acid (ATRA)
arsenic trioxide
298
whats the most common leukaemia in adults
chronic lymphocytic leukaemia (CLL)
299
symptoms of CLL
lymphadenopathy -swollen lymph nodes
organomegaly- enlarged organs
marrow failure
autoimmune disease
300
CLL
chronic lymphocytic leukaemia (CLL)
lymphoproliferative disorder of B lymphocytes
301
blood film of CLL
marked increase in B cell lymphocytes
302
how to diagnose CLL
immunophenotypes (by flow cytometry)- b cell antigens- CD23+, CD19+. co expression of CD5
cytogenetics
- poor prognosis in individuals with deletions in 17p (p53 gene) and 11q21
303
Binet and Rai staging system for CLL
binet staging- more common in UK,stage A, B and C
Rai staging -more common in USA - stage 0,1,2,3,4,5
304
whats over proliferated in CML
cells committed to the myeloid lineage
305
treatment of chronic myeloid leukaemia (CML)
tyrosine kinase inhibitors
e.g. imatinib
306
blood film for CML
numerous granulocytic cells
immature neutrophils
basophils, eosinophils and bands and more immature myeloid cells are increased
not as many blast cells as in AML
307
cytogenetics of CML
first human cancer to be associated with consistant chromosomal abnormality
Philadelphia chromosome t(9;22) in >95% of cases
308
hows leukaemia treated
chemo- cytotoxic drugs
radiotherapy(only with transplantation)- use of high energy rays
stem cell transplantation- bone marrow transplant
309
What are the three main types of cytotoxic chemotherapy drugs?
Anti-metabolites, DNA-binding agents, and Mitotic inhibitors.
310
What is the function of anti-metabolite chemotherapy drugs?
They inhibit DNA synthesis, preventing cancer cells from replicating.
311
How does methotrexate work?
It inhibits folic acid metabolism, blocking nucleotide synthesis and DNA replication.
312
hat is the mechanism of action of cytosine arabinoside (Ara-C)?
It inhibits DNA polymerase, preventing DNA elongation and replication.
313
What is the mechanism of action of Daunorubicin?
It intercalates between base pairs, uncoiling the DNA helix and disrupting replication.
314
What is the function of mitotic inhibitors?
They prevent cell division by disrupting microtubule function.
315
How does Vincristine work?
It inhibits tubulin polymerization, blocking chromosome separation during mitosis.
316
How does Vinblastine work?
It binds to microtubules and prevents purine synthesis, stopping cell replication.
317
How do corticosteroids aid chemotherapy?
-Directly target leukemia cells.
-Enhance the effectiveness of other chemotherapy drugs.
-Reduce chemotherapy side effects.
318
How does trans-retinoic acid help in cancer treatment?
It degrades PML-RAR alpha protein, converting it into a transcription activator, which promotes normal cell differentiation.
319
incidence of CML
age is risk factor
median age of onset= 57-60
sex balance = 1.2-1.7: 1 male:female
320
what are the 3 phases of CML and their duration
chronic - 5-6yrs
accelerated - 6-9months
blast - 3-6months
321
what happens in the chronic phase of CML
mostly mature WBC in blood and bone marrow
may be no symptoms of leukaemia
322
what happens in the accelerated phase of CML
5-30% of WBCs in blood and bone marrow are immature
symptoms - fever, poor appetite and weight loss
323
what happens in the blast phase of CML
most WBC in blood and bone marrow are immature
symptoms - anaemia, recurrent infections
324
what percentage of chronic CML are asymptomatic
50%
325
common symptoms of chronic phase CML
fatigue
weight loss/ anorexia
abdominal fullness
326
common lab findings of chronic phase CML
leukocytosis - increased wBC count
thrombocytopenia
anaemia
basophila - excessive basophils
327
genetics of CML
philadelphia chromosome
reciprocal translocation t(9;22)(q34;q11)
resulting onBCR/ABL oncogene
(long arm of chr9 translocates with chr22
reciprocal translocation drives leukemic clone)
328
what does BCR/ABL stand for
breakpoint cluster region
Abelson 1 kinase
329
how many forms does the BCR/ABL oncogene exist in
3 forms depending on breakpoints on the BCR gene
330
how many fusion proteins does BCR/ABL fusion oncogene give rise to
3 distinct fusion proteins
P190
P210
P230
331
what do the BCR/ABL fusion ocnogenes contain
the same ABL1 sequence but different portions of the BCR sequence
332
the tyrosine kinase domain on the fusion protein is constitutively active
true or false
true
333
whats normal STAT5 signalling
in normal hematopoietic stem cells
JAK2 phosphorylates STAT5 at a tyrosine residue
following which STAT5 translocate to the nucleus to influence gene transcription
334
how does BCR/ABL fusion protein increase cell proliferation
in CML cells the BCR-ABL phosphorylates STAT5 at same tyrosine residue close inducing same downstream eventsindependently of JAK2
phosphate group is provided by ATP binding to the BCR-ABL protein
ultimately increasing cell proliferation and decreases apoptosis
335
whats the current treatment for CML
tyrosine kinase inhibitors
336
how do TKI work for CML treatment
TKI are ATP-mimetic compounds
which compete with ATP for ATP-binding site at BCR-ABL1
this prevents phosphorylation of protein substrates
so oncogenic signlaling pathways are no longer activated and cell undergoes apoptosis
337
how to monitor CML
haematologic responses
cytogenetic response - evaluation of >20 metaphases for pH+ chromosome in bone marrow samples
molecular responses- quantified by measuring the reduction in BCR-ABL1 mRNA transcripts using RT-qPCR
338
