Haemostasis

Blood plays various vital roles within the body and it is not surprising that a number of processes have evolved capable of effectively maintaining haemostasis — the rapid arrest of blood loss upon vascular damage, in order to maintain a relatively constant blood volume. In humans, three main mechanisms underline the haemostatic process  

Pharmaceutical biotechnology concepts and applications Gary Walsh 2007 John Wiley Sons, Ltd ISBN 978 0 470 01244 4 (HB) 978 0 470 01245 1 (PB) 

CH12 RECOMBINANT BLOOD PRODUCTS AND THERAPEUTIC ENZYMES 

Changes in the complex phenomena represented by each of these terms will result in changes in the haemostatic efficiency. The significant values for K are and KJ, the critical thrombotic value and the critical haemorrhagic value. When the product of V.CjF reaches the value Kf at a certain point in the circulation, thrombosis will be initiated. When it falls to K, at a certain point in the circulation, haemorrhage will result. Anticoagulants chiefly (but not solely) affect C (the composition of the blood) to decrease haemostatic efficiency. The three factors, vessel wall, blood composition and blood flow are not completely independent. The vessel wall component is affected by blood composition and blood flow, and vice versa, and situations arise where thrombosis and haemorrhage can occur simultaneously in the circulation of the same individual. 

The physiological and pathological factors modifying these factors, and hence the haemostatic efficiency of the cardiovascular system, have been the subject of many experimental investigations and clinical observations. These are summarized in Table 3.6. 

Cortex mid-brain—limbic system reticular formation— vasomotor centres— -reflex vessel tone pituitary- ACTH, etc. Nutrition  

Blood pressure, blood flow, tissue fluid pressure Blood composition  

Response to Vessel Injury Retraction and constriction of vessels 

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R. G. Macfadane, in R. Biggs, ed.. Human Blood Coagulation, Haemostasis and Thrombosis, 2nd ed., Blackwell Scientific PubHcations, Oxford, 1976, pp. 1-31. 

Haemostasis is the mechanism activated after damage to the blood vessel wall that ensures that blood loss is restricted. Blood platelets are are activated and adhere to elements on the damaged lumenal surface of the vessel, eventually forming a platelet plug that stops the leakage of blood. Fibrinolytic mechanisms later produce lysis of the platelet mass when repair of the vessel has occurred. 

Meuleman DG. Orgaran (Org 10172) its pharmacological profile in animal models. Haemostasis 1992 22 58-65. 

Maffrand JP, Herbert JM, Bernat A, Defreyn G, Delebassee D, Savi P, Pinot JJ, Sampol J. Experimental and clinical pharmacology of pentosan polysulphate. Semin Thrombosis Haemostasis 1991 17 (Suppl. 2) 186-198. 

M15. Massignon, D., Lepape, A., Bienvenu, J., Barbier, Y Boileau, C and Coeur, P Coagula-tion/fibrinolysis balance in septic shock related to cytokines and clinical state. Haemostasis 24, 36-48(1994). 

Nemmar, A. et al. (2007) Enhanced peripheral fhrombogenidty after lung inflammation is mediated by platelet-leukocyte activation role of P-selectin. Journal of Thrombosis and Haemostasis,... 

Although blood clot formation is essential to maintaining haemostasis, inappropriate clotting can give rise to serious, sometimes fatal medical conditions. The formation of a blood clot (a thrombus) often occurs inappropriately within diseased blood vessels. This partially or completely obstructs the flow of blood (and hence oxygen) to the tissues normally served by that blood vessel. 

Hirudin exhibits its anticoagulant effect by tightly binding thrombin, thus inactivating it. In addition to its critical role in the production of a fibrin clot, thrombin displays several other (non-enzymatic) biological activities important in sustaining haemostasis. These include ... 

The natural process of thrombosis functions to plug a damaged blood vessel, thus maintaining haemostasis until the damaged vessel can be repaired. Subsequent to this repair, the clot is removed via an enzymatic degradative process known as fibrinolysis. Fibrinolysis normally depends upon the serine protease plasmin, which is capable of degrading the fibrin strands present in the clot. 

International Society of Thrombosis and Haemostasis (ISTH), 12 151 International Society of Hypertension, on sodium restriction, 22 813 International Solvent Extraction Conferences (ISEC), 10 746, 766 International Standard (ISO) 2370, for flax fiber, 11 614, 616, 617... 

Y2. Yamazaki, M., Asakura, H., Jokaji, H., Saito, M., Uotani, C., Kumabahiri, I., Morishita, E., Aoshima, K., Ikeda, T., and Marsuda, T., Plasma levels of lipoprotein(a) are elevated in patients with the antiphospholipid antibody syndrome. Thromb. Haemostasis 71, 424-427 (1994). 

Haemostasis is achieved by the interplay between platelets, proteins within the plasma (the clotting factors) and endothelial cells. The endothelial cells lining the... 

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