Embolism

This hydrolysis reaction is accelerated by acids or heat and, in some instances, by catalysts. Because the flammable gas hydrogen is formed, a potential fire hazard may result unless adequate ventilation is provided. Ingestion of hydrides must be avoided because hydrolysis to form hydrogen could result in gas embolism. 

The development of injectable mictocapsules for deUvery of chemotherapy agents remains another active area of research. The ultimate goal is to achieve targeted deUvery of chemotherapy agents to specific sites in the body, ideaUy by injection of dmg-loaded mictocapsules that would seek out and destroy diseased ceUs. Intra-arterial infusion chemotherapy is a direct approach to targeted deUvery. The clinical appHcations of microspheres and mictocapsules in embolization and chemotherapy have been assessed (49) (see Chemotherapeutics, anticancer). 

If it is not dissolved or trapped, an embolism moving from the lower extremities can be life-threatening. People afflicted with phlebitis are particularly susceptible to this problem. A shape-memory trap has been devised that, when deployed in the vena cava, is like a multileaved mesh that traps a traveling embolism, retaining it until medication can dissolve it. Introduced in a folded form by a catheter, the mesh is prevented from deploying by subjecting it to a flow of cold saline water. Once in place, it is released from the catheter and, warmed by body heat, opens into its final shape (11). 

Thrombolytic Enzymes. Although atherosclerosis and the accompanying vascular wall defects are ultimately responsible for such diseases as acute pulmonary embolism, arterial occlusion, and myocardial infarction, the lack of blood flow caused by a fibrin clot directly results in tissue injury and in the clinical symptoms of these devastating diseases (54). Thrombolytic enzyme therapy removes the fibrin clot by dissolution, and has shown promise in the treatment of a number of thrombo-occlusive diseases (60). 

Indications for treatment with streptokinase include acute occlusion of arteries, deep vein thrombosis, and pulmonary embolism. Streptokinase therapy in coronary thrombosis, which is the usual cause of myocardial infarction (54,71,72), has proved to be valuable. In this frequently fatal condition, the enzyme is adrninistered intravenously at a dose of 1.5 million units over 60 min, or given by intracoronary infusion at a 20,000- to 50,000-unit bolus dose followed by 2000 to 4000 units/min for 60 min therapy must be instituted as soon as practicable after the diagnosis of heart attack is made. For deep vein thrombosis, pulmonary embolism, or arterial occlusion, streptokinase is infused at a loading dose of 250,000 units given over 30 min, followed by a maintenance dose of 100,000 units over a 60-min period. 

Pulmonary embolism. A blood clot trapped in the blood vessels of the lungs. 

In general, arterial thrombi are platelet-rich ( white clots ) and form at ruptured atherosclerotic plaques, leading to intraluminal occlusion of arteries that can result in end-organ injury (e.g., myocardial infarction, stroke). In contrast, venous thrombi consist mainly of fibrin and red blood cells ( red clots ), and usually form in low-flow veins of the limbs, producing deep vein thrombosis (DVT) the major threat to life results when lower extremity (and, occasionally, upper extremity) venous thrombi embolize via the right heart chambers into the pulmonary arteries, i.e., pulmonary embolism (PE). 

Therapeutically t-PA and urokinase are the most important drugs for fibrinolytic therapy (myocardial infarction, stroke, massive pulmonary embolism). This treatment is associated with an enhanced risk of bleeding complications. 

However, already in an early clinical trial, rofecoxib was found to produce four times the number of myocardial infarctions than its comparator drug, naproxen. A subsequent trial of rofecoxib compared to placebo in colorectal cancer prevention demonstrated, after 18 months of study, that a greater number of myocardial infarctions occulted in the rofecoxib group. In 2004 the manufacturers of rofecoxib withdrew the diug from the market. A similar study of celecoxib compared to placebo in cancer prevention, showed that celecoxib also increased the risk of cardiovascular embolisms [3]. 

Occurs as a result of circulatory insufficiency associated with overwhelming infection Occurs when obstruction of blood flow results in inadequate tissue perfusion. Examples include a severe reduction of blood flow as the result of massive pulmonary embolism, pericardial tamponade, restrictive pericarditis, and severe cardiac valve dysfunction Occurs as a result of blockade of neurohum oral outflow. Examples include from a pharmacological source (ie, spinal anesthesia) or direct injury to the spinal cord. This type of shock is rare. 

Prevention and treatment of atrial fibrillation with embolization... 

Prevention and treatment of venous thrombosis, PE, peripheral arterial embolism ... 

Thromboembolism or fat embolism, thrombophlebitis, necrotizing angiitis, syncopal episodes, cardiac arrhythmias, aggravation of hypertension... 

Hyperstimulation of the uterus during labor may lead to uterine Many with marked impairment of the uteroplacental blood flow, uterine rupture, cervical rupture, amniotic fluid embolism, and trauma to the infant. Overstimulation of the uterus is dangerousto both the fetusand the mother and may occur even when the drug is administered properly in a uterus that is hypersensitive to oxytocin. 

Many serious health problems result from abnormally located blood clots heart attacks (clots in coronary arteries), pulmonary embolism (clots in the lungs), and peripheral arterial occlusion and deep vein thrombosis (clots in the limbs). Each year heart attacks alone afflict over a million people in the United States, and almost half of them die as a result. 

Embolic phenomena may occur from particulate matter such as talc or... 

The well-known adverse reaction formerly often observed after intramuscular injection of clemizol penicilUn in the treatment of syphilis with anaphylaxis-like symptoms plus CNS involvement in the absence of immimological sensitization to penicillin was called the Hoigne syndrome or embolic-toxic reaction, and might be explained by intravasal appUcation of LA with subsequent toxic effects [8]. 

Tissue plasminogen activator 530 amino acids, glycosylated E. coli Yeast Animal cells Acute mycocardial infarct Pulmonary embolism Approved for sale Animal cell culture most effective way of producing active enzyme... 

Streptokinase is administered by intravenous or intra-arterial infusion in the treatment of thrombo-embolic disorders, e g. pulmonary embolism, deep-vein thrombosis and arterial occlusiorrs. It is also used in acute myocardial irtfarclioa... 

Neumann-Haefelin C, Brinker G, Uhlenkuken U, Pillekamp F, Hossmann KA, Hocehn M. Prediction of hemorrhagic transformation after thrombolytic therapy of clot embolism an MRI investigation in rat brain. Stroke 2002 33 1392-1398. 

Ischemic stroke has numerous causes. Cerebral infarction may result from large artery atherosclerosis, cardiac embolism, small artery lipohyalinosis, cryptogenic embolism, or, more rarely, from other diverse conditions such as arterial dissection, infective endocarditis, and sickle cell disease. Arterial occlusion is the cause of at least 80% of acute cerebral infarctions. " ... 

Del Zoppo GJ, Poeck K, Pessin MS, Wolpert SM, Eurlan AJ, Ferhert A, Alberts MJ, Zivin JA, Wechsler L, Busse O. Recombinant tissue plasminogen activator in acute thrombotic and embolic stroke. Ann Neurol. 1992 32 78-86. 

Dijkhuizen RM, Asahi M, Wu O, Rosen BR, Lo EH. Delayed rt-PA treatment in a rat embolic stroke model Diagnosis and prognosis of ischemic injury and hemorrhagic transformation with magnetic resonance imaging. J Cereb Blood Flow Metab. 2001 21 964-971. 

Zivin JA, Fisher M, DeGirolami U, Hemenway CC, Stashak JA. Tissue plasminogen activator reduces neurological damage after cerebral embolism. Science. 1985 230 1289-1292. 

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