Takayasu Arteritis: A chronic inflammatory process that affects the AORTA and its primary branches, such as the brachiocephalic artery (BRACHIOCEPHALIC TRUNK) and CAROTID ARTERIES. It results in progressive arterial stenosis, occlusion, and aneurysm formation. The pulse in the arm is hard to detect. Patients with aortitis syndrome often exhibit retinopathy.Arteritis: INFLAMMATION of any ARTERIES.Giant Cell Arteritis: A systemic autoimmune disorder that typically affects medium and large ARTERIES, usually leading to occlusive granulomatous vasculitis with transmural infiltrate containing multinucleated GIANT CELLS. The TEMPORAL ARTERY is commonly involved. This disorder appears primarily in people over the age of 50. Symptoms include FEVER; FATIGUE; HEADACHE; visual impairment; pain in the jaw and tongue; and aggravation of pain by cold temperatures. (From Adams et al., Principles of Neurology, 6th ed)Arteritis Virus, Equine: The type species of the genus ARTERIVIRUS and the etiologic agent of an important equine respiratory disease causing abortion, pneumonia, or other infections.Temporal Arteries: Arteries arising from the external carotid or the maxillary artery and distributing to the temporal region.Polymyalgia Rheumatica: A syndrome in the elderly characterized by proximal joint and muscle pain, high erythrocyte sedimentation rate, and a self-limiting course. Pain is usually accompanied by evidence of an inflammatory reaction. Women are affected twice as commonly as men and Caucasians more frequently than other groups. The condition is frequently associated with GIANT CELL ARTERITIS and some theories pose the possibility that the two diseases arise from a single etiology or even that they are the same entity.Arterivirus Infections: Infections caused by viruses of the genus ARTERIVIRUS.Polyarteritis Nodosa: A form of necrotizing non-granulomatous inflammation occurring primarily in medium-sized ARTERIES, often with microaneurysms. It is characterized by muscle, joint, and abdominal pain resulting from arterial infarction and scarring in affected organs. Polyarteritis nodosa with lung involvement is called CHURG-STRAUSS SYNDROME.HLA-B52 Antigen: A specific HLA-B surface antigen subtype. Members of this subtype contain alpha chains that are encoded by the HLA-B*52 allele family.Aortic Arch Syndromes: Conditions resulting from abnormalities in the arteries branching from the ASCENDING AORTA, the curved portion of the aorta. These syndromes are results of occlusion or abnormal blood flow to the head-neck or arm region leading to neurological defects and weakness in an arm. These syndromes are associated with vascular malformations; ATHEROSCLEROSIS; TRAUMA; and blood clots.Horse Diseases: Diseases of domestic and wild horses of the species Equus caballus.Blood Sedimentation: Measurement of rate of settling of erythrocytes in anticoagulated blood.Aortitis: Inflammation of the wall of the AORTA.Arterivirus: A genus of the family ARTERIVIRIDAE, in the order NIDOVIRALES. The type species is ARTERITIS VIRUS, EQUINE.Prednisolone: A glucocorticoid with the general properties of the corticosteroids. It is the drug of choice for all conditions in which routine systemic corticosteroid therapy is indicated, except adrenal deficiency states.Subclavian Artery: Artery arising from the brachiocephalic trunk on the right side and from the arch of the aorta on the left side. It distributes to the neck, thoracic wall, spinal cord, brain, meninges, and upper limb.Horses: Large, hoofed mammals of the family EQUIDAE. Horses are active day and night with most of the day spent seeking and consuming food. Feeding peaks occur in the early morning and late afternoon, and there are several daily periods of rest.Subclavian Steal Syndrome: A clinically significant reduction in blood supply to the BRAIN STEM and CEREBELLUM (i.e., VERTEBROBASILAR INSUFFICIENCY) resulting from reversal of blood flow through the VERTEBRAL ARTERY from occlusion or stenosis of the proximal subclavian or brachiocephalic artery. Common symptoms include VERTIGO; SYNCOPE; and INTERMITTENT CLAUDICATION of the involved upper extremity. Subclavian steal may also occur in asymptomatic individuals. (From J Cardiovasc Surg 1994;35(1):11-4; Acta Neurol Scand 1994;90(3):174-8)Axillary Artery: The continuation of the subclavian artery; it distributes over the upper limb, axilla, chest and shoulder.Biopsy: Removal and pathologic examination of specimens in the form of small pieces of tissue from the living body.Optic Neuropathy, Ischemic: Ischemic injury to the OPTIC NERVE which usually affects the OPTIC DISK (optic neuropathy, anterior ischemic) and less frequently the retrobulbar portion of the nerve (optic neuropathy, posterior ischemic). The injury results from occlusion of arterial blood supply which may result from TEMPORAL ARTERITIS; ATHEROSCLEROSIS; COLLAGEN DISEASES; EMBOLISM; DIABETES MELLITUS; and other conditions. The disease primarily occurs in the sixth decade or later and presents with the sudden onset of painless and usually severe monocular visual loss. Anterior ischemic optic neuropathy also features optic disk edema with microhemorrhages. The optic disk appears normal in posterior ischemic optic neuropathy. (Glaser, Neuro-Ophthalmology, 2nd ed, p135)Angiography: Radiography of blood vessels after injection of a contrast medium.Mucocutaneous Lymph Node Syndrome: An acute, febrile, mucocutaneous condition accompanied by swelling of cervical lymph nodes in infants and young children. The principal symptoms are fever, congestion of the ocular conjunctivae, reddening of the lips and oral cavity, protuberance of tongue papillae, and edema or erythema of the extremities.Strongyle Infections, Equine: Infection of horses with parasitic nematodes of the superfamily STRONGYLOIDEA. Characteristics include the development of hemorrhagic nodules on the abdominal peritoneum.Brachiocephalic Trunk: The first and largest artery branching from the aortic arch. It distributes blood to the right side of the head and neck and to the right arm.Vasculitis: Inflammation of any one of the blood vessels, including the ARTERIES; VEINS; and rest of the vasculature system in the body.Vasculitis, Central Nervous System: Inflammation of blood vessels within the central nervous system. Primary vasculitis is usually caused by autoimmune or idiopathic factors, while secondary vasculitis is caused by existing disease process. Clinical manifestations are highly variable but include HEADACHE; SEIZURES; behavioral alterations; INTRACRANIAL HEMORRHAGES; TRANSIENT ISCHEMIC ATTACK; and BRAIN INFARCTION. (From Adams et al., Principles of Neurology, 6th ed, pp856-61)Adrenal Cortex HormonesMagnetic Resonance Angiography: Non-invasive method of vascular imaging and determination of internal anatomy without injection of contrast media or radiation exposure. The technique is used especially in CEREBRAL ANGIOGRAPHY as well as for studies of other vascular structures.Aortography: Radiographic visualization of the aorta and its branches by injection of contrast media, using percutaneous puncture or catheterization procedures.Anti-Inflammatory Agents: Substances that reduce or suppress INFLAMMATION.Lactobacillus casei: A rod-shaped bacterium isolated from milk and cheese, dairy products and dairy environments, sour dough, cow dung, silage, and human mouth, human intestinal contents and stools, and the human vagina.Glucocorticoids: A group of CORTICOSTEROIDS that affect carbohydrate metabolism (GLUCONEOGENESIS, liver glycogen deposition, elevation of BLOOD SUGAR), inhibit ADRENOCORTICOTROPIC HORMONE secretion, and possess pronounced anti-inflammatory activity. They also play a role in fat and protein metabolism, maintenance of arterial blood pressure, alteration of the connective tissue response to injury, reduction in the number of circulating lymphocytes, and functioning of the central nervous system.Aneurysm: Pathological outpouching or sac-like dilatation in the wall of any blood vessel (ARTERIES or VEINS) or the heart (HEART ANEURYSM). It indicates a thin and weakened area in the wall which may later rupture. Aneurysms are classified by location, etiology, or other characteristics.Arachnoiditis: Acute or chronic inflammation of the arachnoid membrane of the meninges most often involving the spinal cord or base of the brain. This term generally refers to a persistent inflammatory process characterized by thickening of the ARACHNOID membrane and dural adhesions. Associated conditions include prior surgery, infections, trauma, SUBARACHNOID HEMORRHAGE, and chemical irritation. Clinical features vary with the site of inflammation, but include cranial neuropathies, radiculopathies, and myelopathies. (From Joynt, Clinical Neurology, 1997, Ch48, p25)AIDS Arteritis, Central Nervous System: Inflammation of ARTERIES in the CENTRAL NERVOUS SYSTEM that occurs in patients with ACQUIRED IMMUNODEFICIENCY SYNDROME or AIDS-RELATED OPPORTUNISTIC INFECTIONS.Prednisone: A synthetic anti-inflammatory glucocorticoid derived from CORTISONE. It is biologically inert and converted to PREDNISOLONE in the liver.Methylprednisolone: A PREDNISOLONE derivative with similar anti-inflammatory action.Infarction: Formation of an infarct, which is NECROSIS in tissue due to local ISCHEMIA resulting from obstruction of BLOOD CIRCULATION, most commonly by a THROMBUS or EMBOLUS.Retinal Artery Occlusion: Sudden ISCHEMIA in the RETINA due to blocked blood flow through the CENTRAL RETINAL ARTERY or its branches leading to sudden complete or partial loss of vision, respectively, in the eye.Blindness: The inability to see or the loss or absence of perception of visual stimuli. This condition may be the result of EYE DISEASES; OPTIC NERVE DISEASES; OPTIC CHIASM diseases; or BRAIN DISEASES affecting the VISUAL PATHWAYS or OCCIPITAL LOBE.Aortic Aneurysm: An abnormal balloon- or sac-like dilatation in the wall of AORTA.Adie Syndrome: A syndrome characterized by a TONIC PUPIL that occurs in combination with decreased lower extremity reflexes. The affected pupil will respond more briskly to accommodation than to light (light-near dissociation) and is supersensitive to dilute pilocarpine eye drops, which induce pupillary constriction. Pathologic features include degeneration of the ciliary ganglion and postganglionic parasympathetic fibers that innervate the pupillary constrictor muscle. (From Adams et al., Principles of Neurology, 6th ed, p279)Renal Artery: A branch of the abdominal aorta which supplies the kidneys, adrenal glands and ureters.Togaviridae: A family of RNA viruses, mainly arboviruses, consisting of two genera: ALPHAVIRUS (group A arboviruses), and RUBIVIRUS. Virions are spherical, 60-70 nm in diameter, with a lipoprotein envelope tightly applied to the icosahedral nucleocapsid.Aorta, Abdominal: The aorta from the DIAPHRAGM to the bifurcation into the right and left common iliac arteries.Vasa Vasorum: Nutrient blood vessels which supply the walls of large arteries or veins.Ultrasonography, Doppler, Color: Ultrasonography applying the Doppler effect, with the superposition of flow information as colors on a gray scale in a real-time image. This type of ultrasonography is well-suited to identifying the location of high-velocity flow (such as in a stenosis) or of mapping the extent of flow in a certain region.Arterial Occlusive Diseases: Pathological processes which result in the partial or complete obstruction of ARTERIES. They are characterized by greatly reduced or absence of blood flow through these vessels. They are also known as arterial insufficiency.Tomography, X-Ray Computed: Tomography using x-ray transmission and a computer algorithm to reconstruct the image.Amaurosis Fugax: Transient complete or partial monocular blindness due to retinal ischemia. This may be caused by emboli from the CAROTID ARTERY (usually in association with CAROTID STENOSIS) and other locations that enter the central RETINAL ARTERY. (From Adams et al., Principles of Neurology, 6th ed, p245)Vertebral Artery: The first branch of the SUBCLAVIAN ARTERY with distribution to muscles of the NECK; VERTEBRAE; SPINAL CORD; CEREBELLUM; and interior of the CEREBRUM.Aortic Valve Insufficiency: Pathological condition characterized by the backflow of blood from the ASCENDING AORTA back into the LEFT VENTRICLE, leading to regurgitation. It is caused by diseases of the AORTIC VALVE or its surrounding tissue (aortic root).Vaccines, Marker: Vaccines used in conjunction with diagnostic tests to differentiate vaccinated animals from carrier animals. Marker vaccines can be either a subunit or a gene-deleted vaccine.Aorta: The main trunk of the systemic arteries.Aorta, Thoracic: The portion of the descending aorta proceeding from the arch of the aorta and extending to the DIAPHRAGM, eventually connecting to the ABDOMINAL AORTA.Retrospective Studies: Studies used to test etiologic hypotheses in which inferences about an exposure to putative causal factors are derived from data relating to characteristics of persons under study or to events or experiences in their past. The essential feature is that some of the persons under study have the disease or outcome of interest and their characteristics are compared with those of unaffected persons.Arteries: The vessels carrying blood away from the heart.Scalp: The outer covering of the calvaria. It is composed of several layers: SKIN; subcutaneous connective tissue; the occipitofrontal muscle which includes the tendinous galea aponeurotica; loose connective tissue; and the pericranium (the PERIOSTEUM of the SKULL).