Biomedical Engineering Reference
In-Depth Information
in stimulating the emission of filopodia. Many more details on vWD can be found
in [5].
Thrombocytopenia (scarcity of platelets)
It can be genetic or acquired, or induced by other illnesses or medical treatments (see
e.g. [43] about Heparin Induced Thrombocytopenia (HIT)). Symptoms can be light
or severe, depending on the platelets count. The adjective purpura often associated
to this illness refers to the appearance of bruises on the skin. Two forms of Thrombo-
cytopenic purpura are known: idiopathic (denoting that the cause is unknown) and
immune (the patient's antibodies attacking platelets). The acronym ITP is good for
both. A mathematical model aimed at predicting the efficacy of splenectomy (spleen
removal) in the cure of ITP has been developed in [12].
Dysfunctions of platelets receptors
They prevent binding of platelets to vWF and other elements. In this category we
find Glanzmann's thrombastenia [31], and Bernard-Soulier syndrome ,[7].Ithas
been observed that the latter disease affects the cytoskeletal architecture (producing
the so-called giant platelets), thus emphasizing that normal functioning of recep-
tors is important in platelets morphology. There are many more disorders related
to platelets dysfunctions: dysfunctions of
α
granules ( Grey Platelets Syndrome and
Quebec Platelets Disorder ), of
granules ( Hermanski-Pudlak , Chediak-Higashi ,
and Griscelli syndromes ), defective platelets ( Wiskott-Aldrich syndrome : affects ag-
gregation, Scott syndrome and Stormorken syndrome : failure of the procoagulant
activity of platelet surface, or non-stimulated activation, respectively). For more in-
formation on platelets related bleeding disorders see [14].
δ
Other rare disorders
Afibrinogenemia (Fibrinogen (FI) deficiency or malfunction) , Hypoprothrombine-
mia (FII deficiency) , FVII deficiency (first recognized in 1951, may produce severe
bleeding symptoms), FX deficiency , FXIII deficiency (may produce bleeding and
can be associated with dysfunctions of the WBCs generating FXIII), Tissue Factor
deficiency , Combined FV+FVIII deficiency [87].
Thrombophilia
Besides disorders caused by the deficiency or dysfunction of elements intervening in
the coagulation process there are also disorders related to deficiency or dysfunction
of elements involved in fibrinolysis. A typical example is plasminogen deficiency.
The consequence is a higher risk of thrombosis, but there can also be other effects
(defective wound healing, ligneous conjunctivitis, etc.). The risk of thrombosis is
increased also by deficiency (type I) or dysfunction (type II) of the coagulation in-
hibitors AT, PC and PS. We recall that the Leiden mutation of FV (making it resistant
to APC) is also a cause of thrombophilia.
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