Streptokinase

Streptokinase is a 48 kDa extracellular bacterial protein produced by several strains of Streptococcus haemolyticus group C. Its ability to induce lysis of blood clots was first demonstrated in 1933. Early therapeutic preparations administered to patients often caused immunological and other complications, usually prompted by impurities present in these products. Chromatographic purification (particularly using gel filtration and ion-exchange columns) overcame many of these initial difficulties. Modern chromatographically pure streptokinase preparations are usually supplied in freeze-dried form. These preparations (still obtained by non-recombinant means) often contain albumin as an excipient. The albumin prevents flocculation of the active ingredient upon its reconstitution.

Streptokinase is a widely employed thrombolytic agent. It is administered to treat a variety of thrombo-embolic disorders, including:

• pulmonary embolism (blockage of the pulmonary artery - which carries blood from the heart to the lungs for oxygenation - by an embolism), which can cause acute heart failure and sudden death;

• deep-vein thrombosis (thrombus formation in deep veins, usually in the legs);

• arterial occlusions (obstruction of an artery);

• acute myocardial infarction.

Streptokinase induces its thrombolytic effect by binding specifically and tightly to plasminogen. This induces a conformational change in the plasminogen molecule that renders it proteolytically active. In this way, the streptokinase-plasminogen complex catalyses the proteolytic conversion of plasminogen to active plasmin.

As a bacterial protein, streptokinase is viewed by the human immune system as an antigenic substance. In some cases, its administration has elicited allergic responses that have ranged from mild rashes to more serious anaphylactic shock (an extreme and generalized allergic response characterized by swelling, constriction of the bronchioles, circulatory collapse and heart failure).

Another disadvantage of streptokinase administration is the associated increased risk of haemorrhage. Streptokinase-activated plasminogen is capable of lysing not only clot-associated fibrin, but also free plasma fibrinogen. This can result in low serum fibrinogen levels and, hence, compromise haemostatic ability. It should not be administered to, for example, patients suffering from coagulation disorders or bleeding conditions such as ulcers. Despite such potential clinical complications, careful administration of streptokinase has saved countless thousands of lives.

Diabetes 2

Diabetes 2

Diabetes is a disease that affects the way your body uses food. Normally, your body converts sugars, starches and other foods into a form of sugar called glucose. Your body uses glucose for fuel. The cells receive the glucose through the bloodstream. They then use insulin a hormone made by the pancreas to absorb the glucose, convert it into energy, and either use it or store it for later use. Learn more...

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