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DNA Down Under
New section on RNA interference as a tool to block virus replication.
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Traumatic
Physical Cell Injury
Cardiac
Haemolytic Anaemia
- Prosthetic heart
valve
- Surface of the valve
can become roughened resulting in some intravascular haemolysis
- Can become an iron
deficient anaemia (haemoglobinuria)
Microcirculation
Lesions
- Conditions resulting
in microangiopathic haemolytic anaemia (small vessels are
either partially thrombosed, narrowed or have a malignancy
associated with them
- Intravascular haemolytic
blood picture
Haemolytic Uraemic Syndrome (HUS)
- Common in children
from 5 months to 2 years of age
- Affects renal
blood vessels
- Can also be associated
with pregnancy and oral contraceptives
- Presents with
acute renal failure, thrombocytopaenia (because of coagulation)
and intravascular haemolysis
- Kidney endothelial
cells are damaged, platelets adhere resulting in coagulation
(disseminated intravascular coagulation, DIC-see below)
- Fibrin tears RBCs
apart
- Kidney rehydration
by peritoneal dialysis, blood transfusions and plasmapheresis
may be used to help the sufferer
Thrombotic Thrombocytopaenic Purpura (TTP)
- Often occurring
spontaneously, mechanism unknown
- May follow infection
- More often seen
in young females
- Kidney failure
but more widespread than in HUS with DIC
if coagulation is activated extensively
- Often develop
neurological symptoms-poor prognosis
- Intravascular haemolysis,
microthrombi, thrombocytopaenic blood picture
Malignancies
- Associated with
the prostate, lung and stomach
- Commonly associated
with DIC
Thermal
Injury
- Burns (>48'C)
cause considerable intravascular haemolysis
- Occurs during
the time cells take to traverse the heated area
- Usually recover
after 24 hours
Haemoglobinuria
Acute
Haemoglobinuria
- Incompatible blood
transfusion
- Haemolytic anaemia
due to drugs or other chemical agents
- Favism
- Acute acquired
haemolytic anaemia
- Haemolytic anaemia
due to infection
- Blackwater fever
- Acute haemolytic
anaemia due to burns
- Snake and spider
bites
Chronic
Haemoglobinuria
- Paroxysmal nocturnal
haemoglobinuria
- Paroxysmal cold
haemoglobinuria
- Cold agglutinin
haemoglobinuria with Raynaud's syndrome
- March haemoglobinuria
- Trauma to RBCs
at surfaces of the hands and feet
- Joggers, martial
artists, severe exercise
- Usually not
life-threatening, no anaemia
Disseminated
Intravascular Coagulation (DIC)
- Release of thromboplastin-like
substances from ruptured RBCs results in the activation
of coagulation
- F XII can react
with exposed collagen via the intrinsic coagulation system
- Obstruction of
the microvasculature occurs resulting in infarction
New
look for June 2003
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