Hypertension, Renovascular: Hypertension due to RENAL ARTERY OBSTRUCTION or compression.Hypertension: Persistently high systemic arterial BLOOD PRESSURE. Based on multiple readings (BLOOD PRESSURE DETERMINATION), hypertension is currently defined as when SYSTOLIC PRESSURE is consistently greater than 140 mm Hg or when DIASTOLIC PRESSURE is consistently 90 mm Hg or more.Renal Artery Obstruction: Narrowing or occlusion of the RENAL ARTERY or arteries. It is due usually to ATHEROSCLEROSIS; FIBROMUSCULAR DYSPLASIA; THROMBOSIS; EMBOLISM, or external pressure. The reduced renal perfusion can lead to renovascular hypertension (HYPERTENSION, RENOVASCULAR).Hypertension, Renal: Persistent high BLOOD PRESSURE due to KIDNEY DISEASES, such as those involving the renal parenchyma, the renal vasculature, or tumors that secrete RENIN.Hypertension, Pulmonary: Increased VASCULAR RESISTANCE in the PULMONARY CIRCULATION, usually secondary to HEART DISEASES or LUNG DISEASES.Renal Artery: A branch of the abdominal aorta which supplies the kidneys, adrenal glands and ureters.Blood Pressure: PRESSURE of the BLOOD on the ARTERIES and other BLOOD VESSELS.Antihypertensive Agents: Drugs used in the treatment of acute or chronic vascular HYPERTENSION regardless of pharmacological mechanism. Among the antihypertensive agents are DIURETICS; (especially DIURETICS, THIAZIDE); ADRENERGIC BETA-ANTAGONISTS; ADRENERGIC ALPHA-ANTAGONISTS; ANGIOTENSIN-CONVERTING ENZYME INHIBITORS; CALCIUM CHANNEL BLOCKERS; GANGLIONIC BLOCKERS; and VASODILATOR AGENTS.Renin: A highly specific (Leu-Leu) endopeptidase that generates ANGIOTENSIN I from its precursor ANGIOTENSINOGEN, leading to a cascade of reactions which elevate BLOOD PRESSURE and increase sodium retention by the kidney in the RENIN-ANGIOTENSIN SYSTEM. The enzyme was formerly listed as EC 3.4.99.19.Radioisotope Renography: Graphic tracing over a time period of radioactivity measured externally over the kidneys following intravenous injection of a radionuclide which is taken up and excreted by the kidneys.Fibromuscular Dysplasia: An idiopathic, segmental, nonatheromatous disease of the musculature of arterial walls, leading to STENOSIS of small and medium-sized arteries. There is true proliferation of SMOOTH MUSCLE CELLS and fibrous tissue. Fibromuscular dysplasia lesions are smooth stenosis and occur most often in the renal and carotid arteries. They may also occur in other peripheral arteries of the extremity.Hypertension, Portal: Abnormal increase of resistance to blood flow within the hepatic PORTAL SYSTEM, frequently seen in LIVER CIRRHOSIS and conditions with obstruction of the PORTAL VEIN.Hypertension, Malignant: A condition of markedly elevated BLOOD PRESSURE with DIASTOLIC PRESSURE usually greater than 120 mm Hg. Malignant hypertension is characterized by widespread vascular damage, PAPILLEDEMA, retinopathy, HYPERTENSIVE ENCEPHALOPATHY, and renal dysfunction.Kidney: Body organ that filters blood for the secretion of URINE and that regulates ion concentrations.Renal Circulation: The circulation of the BLOOD through the vessels of the KIDNEY.Captopril: A potent and specific inhibitor of PEPTIDYL-DIPEPTIDASE A. It blocks the conversion of ANGIOTENSIN I to ANGIOTENSIN II, a vasoconstrictor and important regulator of arterial blood pressure. Captopril acts to suppress the RENIN-ANGIOTENSIN SYSTEM and inhibits pressure responses to exogenous angiotensin.Chlormerodrin: A mercurial compound that has been used as a diuretic but is now superseded by more potent and less toxic drugs. The radiolabeled form has been used as a diagnostic and research tool.Nephrectomy: Excision of kidney.Angiotensin II: An octapeptide that is a potent but labile vasoconstrictor. It is produced from angiotensin I after the removal of two amino acids at the C-terminal by ANGIOTENSIN CONVERTING ENZYME. The amino acid in position 5 varies in different species. To block VASOCONSTRICTION and HYPERTENSION effect of angiotensin II, patients are often treated with ACE INHIBITORS or with ANGIOTENSIN II TYPE 1 RECEPTOR BLOCKERS.Iodohippuric Acid: An iodine-containing compound used in pyelography as a radiopaque medium. If labeled with radioiodine, it can be used for studies of renal function.Rats, Inbred SHR: A strain of Rattus norvegicus with elevated blood pressure used as a model for studying hypertension and stroke.Mercury Radioisotopes: Unstable isotopes of mercury that decay or disintegrate emitting radiation. Hg atoms with atomic weights 185-195, 197, 203, 205, and 206 are radioactive mercury isotopes.Angioplasty, Balloon: Use of a balloon catheter for dilation of an occluded artery. It is used in treatment of arterial occlusive diseases, including renal artery stenosis and arterial occlusions in the leg. For the specific technique of BALLOON DILATION in coronary arteries, ANGIOPLASTY, BALLOON, CORONARY is available.Renin-Angiotensin System: A BLOOD PRESSURE regulating system of interacting components that include RENIN; ANGIOTENSINOGEN; ANGIOTENSIN CONVERTING ENZYME; ANGIOTENSIN I; ANGIOTENSIN II; and angiotensinase. Renin, an enzyme produced in the kidney, acts on angiotensinogen, an alpha-2 globulin produced by the liver, forming ANGIOTENSIN I. Angiotensin-converting enzyme, contained in the lung, acts on angiotensin I in the plasma converting it to ANGIOTENSIN II, an extremely powerful vasoconstrictor. Angiotensin II causes contraction of the arteriolar and renal VASCULAR SMOOTH MUSCLE, leading to retention of salt and water in the KIDNEY and increased arterial blood pressure. In addition, angiotensin II stimulates the release of ALDOSTERONE from the ADRENAL CORTEX, which in turn also increases salt and water retention in the kidney. Angiotensin-converting enzyme also breaks down BRADYKININ, a powerful vasodilator and component of the KALLIKREIN-KININ SYSTEM.Technetium Tc 99m Pentetate: A technetium imaging agent used in renal scintigraphy, computed tomography, lung ventilation imaging, gastrointestinal scintigraphy, and many other procedures which employ radionuclide imaging agents.Angiography: Radiography of blood vessels after injection of a contrast medium.Rats, Inbred WKY: A strain of Rattus norvegicus used as a normotensive control for the spontaneous hypertensive rats (SHR).Hyperaldosteronism: A condition caused by the overproduction of ALDOSTERONE. It is characterized by sodium retention and potassium excretion with resultant HYPERTENSION and HYPOKALEMIA.Vascular Resistance: The force that opposes the flow of BLOOD through a vascular bed. It is equal to the difference in BLOOD PRESSURE across the vascular bed divided by the CARDIAC OUTPUT.Hypertension, Pregnancy-Induced: A condition in pregnant women with elevated systolic (>140 mm Hg) and diastolic (>90 mm Hg) blood pressure on at least two occasions 6 h apart. HYPERTENSION complicates 8-10% of all pregnancies, generally after 20 weeks of gestation. Gestational hypertension can be divided into several broad categories according to the complexity and associated symptoms, such as EDEMA; PROTEINURIA; SEIZURES; abnormalities in BLOOD COAGULATION and liver functions.Angiotensin-Converting Enzyme Inhibitors: A class of drugs whose main indications are the treatment of hypertension and heart failure. They exert their hemodynamic effect mainly by inhibiting the renin-angiotensin system. They also modulate sympathetic nervous system activity and increase prostaglandin synthesis. They cause mainly vasodilation and mild natriuresis without affecting heart rate and contractility.Renal Veins: Short thick veins which return blood from the kidneys to the vena cava.Blood Pressure Determination: Techniques for measuring blood pressure.Hypertrophy, Left Ventricular: Enlargement of the LEFT VENTRICLE of the heart. This increase in ventricular mass is attributed to sustained abnormal pressure or volume loads and is a contributor to cardiovascular morbidity and mortality.Risk Factors: An aspect of personal behavior or lifestyle, environmental exposure, or inborn or inherited characteristic, which, on the basis of epidemiologic evidence, is known to be associated with a health-related condition considered important to prevent.Hemodynamics: The movement and the forces involved in the movement of the blood through the CARDIOVASCULAR SYSTEM.Ocular Hypertension: A condition in which the intraocular pressure is elevated above normal and which may lead to glaucoma.Glomerular Filtration Rate: The volume of water filtered out of plasma through glomerular capillary walls into Bowman's capsules per unit of time. It is considered to be equivalent to INULIN clearance.Rats, Sprague-Dawley: A strain of albino rat used widely for experimental purposes because of its calmness and ease of handling. It was developed by the Sprague-Dawley Animal Company.Technetium Tc 99m Mertiatide: A technetium diagnostic aid used in renal function determination.Sympathetic Nervous System: The thoracolumbar division of the autonomic nervous system. Sympathetic preganglionic fibers originate in neurons of the intermediolateral column of the spinal cord and project to the paravertebral and prevertebral ganglia, which in turn project to target organs. The sympathetic nervous system mediates the body's response to stressful situations, i.e., the fight or flight reactions. It often acts reciprocally to the parasympathetic system.Pulmonary Artery: The short wide vessel arising from the conus arteriosus of the right ventricle and conveying unaerated blood to the lungs.Disease Models, Animal: Naturally occurring or experimentally induced animal diseases with pathological processes sufficiently similar to those of human diseases. They are used as study models for human diseases.Aldosterone: A hormone secreted by the ADRENAL CORTEX that regulates electrolyte and water balance by increasing the renal retention of sodium and the excretion of potassium.Kidney Function Tests: Laboratory tests used to evaluate how well the kidneys are working through examination of blood and urine.Heart Rate: The number of times the HEART VENTRICLES contract per unit of time, usually per minute.Follow-Up Studies: Studies in which individuals or populations are followed to assess the outcome of exposures, procedures, or effects of a characteristic, e.g., occurrence of disease.Vasodilator Agents: Drugs used to cause dilation of the blood vessels.Arterial Pressure: The blood pressure in the ARTERIES. It is commonly measured with a SPHYGMOMANOMETER on the upper arm which represents the arterial pressure in the BRACHIAL ARTERY.Enalapril: An angiotensin-converting enzyme inhibitor that is used to treat HYPERTENSION and HEART FAILURE.Losartan: An antagonist of ANGIOTENSIN TYPE 1 RECEPTOR with antihypertensive activity due to the reduced pressor effect of ANGIOTENSIN II.CreatinineIntracranial Hypertension: Increased pressure within the cranial vault. This may result from several conditions, including HYDROCEPHALUS; BRAIN EDEMA; intracranial masses; severe systemic HYPERTENSION; PSEUDOTUMOR CEREBRI; and other disorders.Time Factors: Elements of limited time intervals, contributing to particular results or situations.Treatment Outcome: Evaluation undertaken to assess the results or consequences of management and procedures used in combating disease in order to determine the efficacy, effectiveness, safety, and practicability of these interventions in individual cases or series.Arteriosclerosis: Thickening and loss of elasticity of the walls of ARTERIES of all sizes. There are many forms classified by the types of lesions and arteries involved, such as ATHEROSCLEROSIS with fatty lesions in the ARTERIAL INTIMA of medium and large muscular arteries.Prevalence: The total number of cases of a given disease in a specified population at a designated time. It is differentiated from INCIDENCE, which refers to the number of new cases in the population at a given time.Vasoconstrictor Agents: Drugs used to cause constriction of the blood vessels.Kidney Diseases: Pathological processes of the KIDNEY or its component tissues.Rats, Wistar: A strain of albino rat developed at the Wistar Institute that has spread widely at other institutions. This has markedly diluted the original strain.Pentetic Acid: An iron chelating agent with properties like EDETIC ACID. DTPA has also been used as a chelator for other metals, such as plutonium.Cardiomegaly: Enlargement of the HEART, usually indicated by a cardiothoracic ratio above 0.50. Heart enlargement may involve the right, the left, or both HEART VENTRICLES or HEART ATRIA. Cardiomegaly is a nonspecific symptom seen in patients with chronic systolic heart failure (HEART FAILURE) or several forms of CARDIOMYOPATHIES.Desoxycorticosterone: A steroid metabolite that is the 11-deoxy derivative of CORTICOSTERONE and the 21-hydroxy derivative of PROGESTERONE.Nitric Oxide: A free radical gas produced endogenously by a variety of mammalian cells, synthesized from ARGININE by NITRIC OXIDE SYNTHASE. Nitric oxide is one of the ENDOTHELIUM-DEPENDENT RELAXING FACTORS released by the vascular endothelium and mediates VASODILATION. It also inhibits platelet aggregation, induces disaggregation of aggregated platelets, and inhibits platelet adhesion to the vascular endothelium. Nitric oxide activates cytosolic GUANYLATE CYCLASE and thus elevates intracellular levels of CYCLIC GMP.Hypertensive Retinopathy: Degenerative changes to the RETINA due to HYPERTENSION.Prospective Studies: Observation of a population for a sufficient number of persons over a sufficient number of years to generate incidence or mortality rates subsequent to the selection of the study group.Organ Size: The measurement of an organ in volume, mass, or heaviness.Hypertrophy, Right Ventricular: Enlargement of the RIGHT VENTRICLE of the heart. This increase in ventricular mass is often attributed to PULMONARY HYPERTENSION and is a contributor to cardiovascular morbidity and mortality.Sodium Chloride, Dietary: Sodium chloride used in foods.Fibrosis: Any pathological condition where fibrous connective tissue invades any organ, usually as a consequence of inflammation or other injury.Blood Pressure Monitoring, Ambulatory: Method in which repeated blood pressure readings are made while the patient undergoes normal daily activities. It allows quantitative analysis of the high blood pressure load over time, can help distinguish between types of HYPERTENSION, and can assess the effectiveness of antihypertensive therapy.Receptor, Angiotensin, Type 1: An angiotensin receptor subtype that is expressed at high levels in a variety of adult tissues including the CARDIOVASCULAR SYSTEM, the KIDNEY, the ENDOCRINE SYSTEM and the NERVOUS SYSTEM. Activation of the type 1 angiotensin receptor causes VASOCONSTRICTION and sodium retention.TetrazolesRetrospective 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.Angiotensin II Type 1 Receptor Blockers: Agents that antagonize ANGIOTENSIN II TYPE 1 RECEPTOR. Included are ANGIOTENSIN II analogs such as SARALASIN and biphenylimidazoles such as LOSARTAN. Some are used as ANTIHYPERTENSIVE AGENTS.Monocrotaline: A pyrrolizidine alkaloid and a toxic plant constituent that poisons livestock and humans through the ingestion of contaminated grains and other foods. The alkaloid causes pulmonary artery hypertension, right ventricular hypertrophy, and pathological changes in the pulmonary vasculature. Significant attenuation of the cardiopulmonary changes are noted after oral magnesium treatment.Pregnancy Complications, Cardiovascular: The co-occurrence of pregnancy and a cardiovascular disease. The disease may precede or follow FERTILIZATION and it may or may not have a deleterious effect on the pregnant woman or FETUS.Norepinephrine: Precursor of epinephrine that is secreted by the adrenal medulla and is a widespread central and autonomic neurotransmitter. Norepinephrine is the principal transmitter of most postganglionic sympathetic fibers and of the diffuse projection system in the brain arising from the locus ceruleus. It is also found in plants and is used pharmacologically as a sympathomimetic.Vasodilation: The physiological widening of BLOOD VESSELS by relaxing the underlying VASCULAR SMOOTH MUSCLE.Atherosclerosis: A thickening and loss of elasticity of the walls of ARTERIES that occurs with formation of ATHEROSCLEROTIC PLAQUES within the ARTERIAL INTIMA.Angiotensin I: A decapeptide that is cleaved from precursor angiotensinogen by RENIN. Angiotensin I has limited biological activity. It is converted to angiotensin II, a potent vasoconstrictor, after the removal of two amino acids at the C-terminal by ANGIOTENSIN CONVERTING ENZYME.Urography: Radiography of any part of the urinary tract.Spironolactone: A potassium sparing diuretic that acts by antagonism of aldosterone in the distal renal tubules. It is used mainly in the treatment of refractory edema in patients with congestive heart failure, nephrotic syndrome, or hepatic cirrhosis. Its effects on the endocrine system are utilized in the treatments of hirsutism and acne but they can lead to adverse effects. (From Martindale, The Extra Pharmacopoeia, 30th ed, p827)Vasoconstriction: The physiological narrowing of BLOOD VESSELS by contraction of the VASCULAR SMOOTH MUSCLE.Paraventricular Hypothalamic Nucleus: Nucleus in the anterior part of the HYPOTHALAMUS.Chronic Disease: Diseases which have one or more of the following characteristics: they are permanent, leave residual disability, are caused by nonreversible pathological alteration, require special training of the patient for rehabilitation, or may be expected to require a long period of supervision, observation, or care. (Dictionary of Health Services Management, 2d ed)Angiotensins: Oligopeptides which are important in the regulation of blood pressure (VASOCONSTRICTION) and fluid homeostasis via the RENIN-ANGIOTENSIN SYSTEM. These include angiotensins derived naturally from precursor ANGIOTENSINOGEN, and those synthesized.Body Weight: The mass or quantity of heaviness of an individual. It is expressed by units of pounds or kilograms.Proteinuria: The presence of proteins in the urine, an indicator of KIDNEY DISEASES.Endothelium, Vascular: Single pavement layer of cells which line the luminal surface of the entire vascular system and regulate the transport of macromolecules and blood components.Aorta: The main trunk of the systemic arteries.Endothelin-1: A 21-amino acid peptide produced in a variety of tissues including endothelial and vascular smooth-muscle cells, neurons and astrocytes in the central nervous system, and endometrial cells. It acts as a modulator of vasomotor tone, cell proliferation, and hormone production. (N Eng J Med 1995;333(6):356-63)Teprotide: A synthetic nonapeptide (Pyr-Trp-Pro-Arg-Pro-Gln-Ile-Pro-Pro) which is identical to the peptide from the venom of the snake, Bothrops jararaca. It inhibits kininase II and ANGIOTENSIN I and has been proposed as an antihypertensive agent.Arteries: The vessels carrying blood away from the heart.Arterioles: The smallest divisions of the arteries located between the muscular arteries and the capillaries.Peptidyl-Dipeptidase A: A peptidyl-dipeptidase that catalyzes the release of a C-terminal dipeptide, -Xaa-*-Xbb-Xcc, when neither Xaa nor Xbb is Pro. It is a Cl(-)-dependent, zinc glycoprotein that is generally membrane-bound and active at neutral pH. It may also have endopeptidase activity on some substrates. (From Enzyme Nomenclature, 1992) EC 3.4.15.1.Ultrasonography, Doppler, Duplex: Ultrasonography applying the Doppler effect combined with real-time imaging. The real-time image is created by rapid movement of the ultrasound beam. A powerful advantage of this technique is the ability to estimate the velocity of flow from the Doppler shift frequency.Rats, Inbred Strains: Genetically identical individuals developed from brother and sister matings which have been carried out for twenty or more generations or by parent x offspring matings carried out with certain restrictions. This also includes animals with a long history of closed colony breeding.Furosemide: A benzoic-sulfonamide-furan. It is a diuretic with fast onset and short duration that is used for EDEMA and chronic RENAL INSUFFICIENCY.Sodium: A member of the alkali group of metals. It has the atomic symbol Na, atomic number 11, and atomic weight 23.Magnetic 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.Angiography, Digital Subtraction: A method of delineating blood vessels by subtracting a tissue background image from an image of tissue plus intravascular contrast material that attenuates the X-ray photons. The background image is determined from a digitized image taken a few moments before injection of the contrast material. The resulting angiogram is a high-contrast image of the vessel. This subtraction technique allows extraction of a high-intensity signal from the superimposed background information. The image is thus the result of the differential absorption of X-rays by different tissues.Kidney Failure, Chronic: The end-stage of CHRONIC RENAL INSUFFICIENCY. It is characterized by the severe irreversible kidney damage (as measured by the level of PROTEINURIA) and the reduction in GLOMERULAR FILTRATION RATE to less than 15 ml per min (Kidney Foundation: Kidney Disease Outcome Quality Initiative, 2002). These patients generally require HEMODIALYSIS or KIDNEY TRANSPLANTATION.Receptors, Angiotensin: Cell surface proteins that bind ANGIOTENSINS and trigger intracellular changes influencing the behavior of cells.Endarterectomy: Surgical excision, performed under general anesthesia, of the atheromatous tunica intima of an artery. When reconstruction of an artery is performed as an endovascular procedure through a catheter, it is called ATHERECTOMY.Pseudotumor Cerebri: A condition marked by raised intracranial pressure and characterized clinically by HEADACHES; NAUSEA; PAPILLEDEMA, peripheral constriction of the visual fields, transient visual obscurations, and pulsatile TINNITUS. OBESITY is frequently associated with this condition, which primarily affects women between 20 and 44 years of age. Chronic PAPILLEDEMA may lead to optic nerve injury (see OPTIC NERVE DISEASES) and visual loss (see BLINDNESS).Angioplasty: Reconstruction or repair of a blood vessel, which includes the widening of a pathological narrowing of an artery or vein by the removal of atheromatous plaque material and/or the endothelial lining as well, or by dilatation (BALLOON ANGIOPLASTY) to compress an ATHEROMA. Except for ENDARTERECTOMY, usually these procedures are performed via catheterization as minimally invasive ENDOVASCULAR PROCEDURES.Hypertrophy: General increase in bulk of a part or organ due to CELL ENLARGEMENT and accumulation of FLUIDS AND SECRETIONS, not due to tumor formation, nor to an increase in the number of cells (HYPERPLASIA).Receptors, Endothelin: Cell surface proteins that bind ENDOTHELINS with high affinity and trigger intracellular changes which influence the behavior of cells.Microcirculation: The circulation of the BLOOD through the MICROVASCULAR NETWORK.Cardiovascular Diseases: Pathological conditions involving the CARDIOVASCULAR SYSTEM including the HEART; the BLOOD VESSELS; or the PERICARDIUM.Dose-Response Relationship, Drug: The relationship between the dose of an administered drug and the response of the organism to the drug.Sodium, Dietary: Sodium or sodium compounds used in foods or as a food. The most frequently used compounds are sodium chloride or sodium glutamate.Myocardium: The muscle tissue of the HEART. It is composed of striated, involuntary muscle cells (MYOCYTES, CARDIAC) connected to form the contractile pump to generate blood flow.Reference Values: The range or frequency distribution of a measurement in a population (of organisms, organs or things) that has not been selected for the presence of disease or abnormality.Baroreflex: A response by the BARORECEPTORS to increased BLOOD PRESSURE. Increased pressure stretches BLOOD VESSELS which activates the baroreceptors in the vessel walls. The net response of the CENTRAL NERVOUS SYSTEM is a reduction of central sympathetic outflow. This reduces blood pressure both by decreasing peripheral VASCULAR RESISTANCE and by lowering CARDIAC OUTPUT. Because the baroreceptors are tonically active, the baroreflex can compensate rapidly for both increases and decreases in blood pressure.Systole: Period of contraction of the HEART, especially of the HEART VENTRICLES.Arginine: An essential amino acid that is physiologically active in the L-form.Diet, Sodium-Restricted: A diet which contains very little sodium chloride. It is prescribed by some for hypertension and for edematous states. (Dorland, 27th ed)Surgical Instruments: Hand-held tools or implements used by health professionals for the performance of surgical tasks.Radionuclide Imaging: The production of an image obtained by cameras that detect the radioactive emissions of an injected radionuclide as it has distributed differentially throughout tissues in the body. The image obtained from a moving detector is called a scan, while the image obtained from a stationary camera device is called a scintiphotograph.Receptor, Endothelin A: A subtype of endothelin receptor found predominantly in the VASCULAR SMOOTH MUSCLE. It has a high affinity for ENDOTHELIN-1 and ENDOTHELIN-2.Blood Vessels: Any of the tubular vessels conveying the blood (arteries, arterioles, capillaries, venules, and veins).Diuretics: Agents that promote the excretion of urine through their effects on kidney function.Acetylcholine: A neurotransmitter found at neuromuscular junctions, autonomic ganglia, parasympathetic effector junctions, a subset of sympathetic effector junctions, and at many sites in the central nervous system.Stents: Devices that provide support for tubular structures that are being anastomosed or for body cavities during skin grafting.Rats, Inbred Dahl: Inbred rats derived from Sprague-Dawley rats and used for the study of salt-dependent hypertension. Salt-sensitive and salt-resistant strains have been selectively bred to show the opposite genetically determined blood pressure responses to excess sodium chloride ingestion.Hydrochlorothiazide: A thiazide diuretic often considered the prototypical member of this class. It reduces the reabsorption of electrolytes from the renal tubules. This results in increased excretion of water and electrolytes, including sodium, potassium, chloride, and magnesium. It is used in the treatment of several disorders including edema, hypertension, diabetes insipidus, and hypoparathyroidism.Pulmonary Circulation: The circulation of the BLOOD through the LUNGS.Aorta, Abdominal: The aorta from the DIAPHRAGM to the bifurcation into the right and left common iliac arteries.Endothelins: 21-Amino-acid peptides produced by vascular endothelial cells and functioning as potent vasoconstrictors. The endothelin family consists of three members, ENDOTHELIN-1; ENDOTHELIN-2; and ENDOTHELIN-3. All three peptides contain 21 amino acids, but vary in amino acid composition. The three peptides produce vasoconstrictor and pressor responses in various parts of the body. However, the quantitative profiles of the pharmacological activities are considerably different among the three isopeptides.Severity of Illness Index: Levels within a diagnostic group which are established by various measurement criteria applied to the seriousness of a patient's disorder.Oxidative Stress: A disturbance in the prooxidant-antioxidant balance in favor of the former, leading to potential damage. Indicators of oxidative stress include damaged DNA bases, protein oxidation products, and lipid peroxidation products (Sies, Oxidative Stress, 1991, pxv-xvi).Case-Control Studies: Studies which start with the identification of persons with a disease of interest and a control (comparison, referent) group without the disease. The relationship of an attribute to the disease is examined by comparing diseased and non-diseased persons with regard to the frequency or levels of the attribute in each group.Regional Blood Flow: The flow of BLOOD through or around an organ or region of the body.p-Aminohippuric Acid: The glycine amide of 4-aminobenzoic acid. Its sodium salt is used as a diagnostic aid to measure effective renal plasma flow (ERPF) and excretory capacity.Adrenergic beta-Antagonists: Drugs that bind to but do not activate beta-adrenergic receptors thereby blocking the actions of beta-adrenergic agonists. Adrenergic beta-antagonists are used for treatment of hypertension, cardiac arrhythmias, angina pectoris, glaucoma, migraine headaches, and anxiety.Persistent Fetal Circulation Syndrome: A syndrome of persistent PULMONARY HYPERTENSION in the newborn infant (INFANT, NEWBORN) without demonstrable HEART DISEASES. This neonatal condition can be caused by severe pulmonary vasoconstriction (reactive type), hypertrophy of pulmonary arterial muscle (hypertrophic type), or abnormally developed pulmonary arterioles (hypoplastic type). The newborn patient exhibits CYANOSIS and ACIDOSIS due to the persistence of fetal circulatory pattern of right-to-left shunting of blood through a patent ductus arteriosus (DUCTUS ARTERIOSUS, PATENT) and at times a patent foramen ovale (FORAMEN OVALE, PATENT).Nitroprusside: A powerful vasodilator used in emergencies to lower blood pressure or to improve cardiac function. It is also an indicator for free sulfhydryl groups in proteins.Ultrasonography, Doppler: Ultrasonography applying the Doppler effect, with frequency-shifted ultrasound reflections produced by moving targets (usually red blood cells) in the bloodstream along the ultrasound axis in direct proportion to the velocity of movement of the targets, to determine both direction and velocity of blood flow. (Stedman, 25th ed)Cross-Sectional Studies: Studies in which the presence or absence of disease or other health-related variables are determined in each member of the study population or in a representative sample at one particular time. This contrasts with LONGITUDINAL STUDIES which are followed over a period of time.Vascular Surgical Procedures: Operative procedures for the treatment of vascular disorders.NG-Nitroarginine Methyl Ester: A non-selective inhibitor of nitric oxide synthase. It has been used experimentally to induce hypertension.Sus scrofa: A species of SWINE, in the family Suidae, comprising a number of subspecies including the domestic pig Sus scrofa domestica.Muscle, Smooth, Vascular: The nonstriated involuntary muscle tissue of blood vessels.Pheochromocytoma: A usually benign, well-encapsulated, lobular, vascular tumor of chromaffin tissue of the ADRENAL MEDULLA or sympathetic paraganglia. The cardinal symptom, reflecting the increased secretion of EPINEPHRINE and NOREPINEPHRINE, is HYPERTENSION, which may be persistent or intermittent. During severe attacks, there may be HEADACHE; SWEATING, palpitation, apprehension, TREMOR; PALLOR or FLUSHING of the face, NAUSEA and VOMITING, pain in the CHEST and ABDOMEN, and paresthesias of the extremities. The incidence of malignancy is as low as 5% but the pathologic distinction between benign and malignant pheochromocytomas is not clear. (Dorland, 27th ed; DeVita Jr et al., Cancer: Principles & Practice of Oncology, 3d ed, p1298)Analysis of Variance: A statistical technique that isolates and assesses the contributions of categorical independent variables to variation in the mean of a continuous dependent variable.Diabetes Mellitus: A heterogeneous group of disorders characterized by HYPERGLYCEMIA and GLUCOSE INTOLERANCE.Predictive Value of Tests: In screening and diagnostic tests, the probability that a person with a positive test is a true positive (i.e., has the disease), is referred to as the predictive value of a positive test; whereas, the predictive value of a negative test is the probability that the person with a negative test does not have the disease. Predictive value is related to the sensitivity and specificity of the test.Heart: The hollow, muscular organ that maintains the circulation of the blood.Masked Hypertension: Phenomenon where increased BLOOD PRESSURE readings taken in non-clinical settings (e.g., HOME BLOOD PRESSURE MONITORING) do not replicate in clinical settings.Age Factors: Age as a constituent element or influence contributing to the production of a result. It may be applicable to the cause or the effect of a circumstance. It is used with human or animal concepts but should be differentiated from AGING, a physiological process, and TIME FACTORS which refers only to the passage of time.Methoxamine: An alpha-1 adrenergic agonist that causes prolonged peripheral VASOCONSTRICTION.Obesity: A status with BODY WEIGHT that is grossly above the acceptable or desirable weight, usually due to accumulation of excess FATS in the body. The standards may vary with age, sex, genetic or cultural background. In the BODY MASS INDEX, a BMI greater than 30.0 kg/m2 is considered obese, and a BMI greater than 40.0 kg/m2 is considered morbidly obese (MORBID OBESITY).Diuresis: An increase in the excretion of URINE. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)Prehypertension: Blood pressure levels that are between normotension and hypertension. Individuals with prehypertension are at a higher risk for developing cardiovascular diseases. Generally, prehypertension is defined as SYSTOLIC PRESSURE of 131-139 mm Hg and/or DIASTOLIC PRESSURE of 81-89 when the optimal is 120/80 mm Hg. For diabetics and other metabolism diseases the prehypertension is around 110-129/70-79 mm Hg.Cohort Studies: Studies in which subsets of a defined population are identified. These groups may or may not be exposed to factors hypothesized to influence the probability of the occurrence of a particular disease or other outcome. Cohorts are defined populations which, as a whole, are followed in an attempt to determine distinguishing subgroup characteristics.Angiotensinogen: An alpha-globulin of about 453 amino acids, depending on the species. It is produced by the liver and secreted into blood circulation. Angiotensinogen is the inactive precursor of natural angiotensins. Upon successive enzyme cleavages, angiotensinogen yields angiotensin I, II, and III with amino acids numbered at 10, 8, and 7, respectively.Dipeptidyl-Peptidase IV Inhibitors: Compounds that suppress the degradation of INCRETINS by blocking the action of DIPEPTIDYL-PEPTIDASE IV. This helps to correct the defective INSULIN and GLUCAGON secretion characteristic of TYPE 2 DIABETES MELLITUS by stimulating insulin secretion and suppressing glucagon release.Anoxia: Relatively complete absence of oxygen in one or more tissues.Sodium Chloride: A ubiquitous sodium salt that is commonly used to season food.Kidney Glomerulus: A cluster of convoluted capillaries beginning at each nephric tubule in the kidney and held together by connective tissue.Nitric Oxide Synthase Type III: A CALCIUM-dependent, constitutively-expressed form of nitric oxide synthase found primarily in ENDOTHELIAL CELLS.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.Biphenyl CompoundsIschemia: A hypoperfusion of the BLOOD through an organ or tissue caused by a PATHOLOGIC CONSTRICTION or obstruction of its BLOOD VESSELS, or an absence of BLOOD CIRCULATION.Nitric Oxide Synthase: An NADPH-dependent enzyme that catalyzes the conversion of L-ARGININE and OXYGEN to produce CITRULLINE and NITRIC OXIDE.Heart Ventricles: The lower right and left chambers of the heart. The right ventricle pumps venous BLOOD into the LUNGS and the left ventricle pumps oxygenated blood into the systemic arterial circulation.African Continental Ancestry Group: Individuals whose ancestral origins are in the continent of Africa.Renal Insufficiency: Conditions in which the KIDNEYS perform below the normal level in the ability to remove wastes, concentrate URINE, and maintain ELECTROLYTE BALANCE; BLOOD PRESSURE; and CALCIUM metabolism. Renal insufficiency can be classified by the degree of kidney damage (as measured by the level of PROTEINURIA) and reduction in GLOMERULAR FILTRATION RATE.Phenylephrine: An alpha-1 adrenergic agonist used as a mydriatic, nasal decongestant, and cardiotonic agent.Pressoreceptors: Receptors in the vascular system, particularly the aorta and carotid sinus, which are sensitive to stretch of the vessel walls.Atrial Natriuretic Factor: A potent natriuretic and vasodilatory peptide or mixture of different-sized low molecular weight PEPTIDES derived from a common precursor and secreted mainly by the HEART ATRIUM. All these peptides share a sequence of about 20 AMINO ACIDS.Pre-Eclampsia: A complication of PREGNANCY, characterized by a complex of symptoms including maternal HYPERTENSION and PROTEINURIA with or without pathological EDEMA. Symptoms may range between mild and severe. Pre-eclampsia usually occurs after the 20th week of gestation, but may develop before this time in the presence of trophoblastic disease.Sensitivity and Specificity: Binary classification measures to assess test results. Sensitivity or recall rate is the proportion of true positives. Specificity is the probability of correctly determining the absence of a condition. (From Last, Dictionary of Epidemiology, 2d ed)Imidazoles: Compounds containing 1,3-diazole, a five membered aromatic ring containing two nitrogen atoms separated by one of the carbons. Chemically reduced ones include IMIDAZOLINES and IMIDAZOLIDINES. Distinguish from 1,2-diazole (PYRAZOLES).Albuminuria: The presence of albumin in the urine, an indicator of KIDNEY DISEASES.Hypercholesterolemia: A condition with abnormally high levels of CHOLESTEROL in the blood. It is defined as a cholesterol value exceeding the 95th percentile for the population.Sex Factors: Maleness or femaleness as a constituent element or influence contributing to the production of a result. It may be applicable to the cause or effect of a circumstance. It is used with human or animal concepts but should be differentiated from SEX CHARACTERISTICS, anatomical or physiological manifestations of sex, and from SEX DISTRIBUTION, the number of males and females in given circumstances.Neuropeptide Y: A 36-amino acid peptide present in many organs and in many sympathetic noradrenergic neurons. It has vasoconstrictor and natriuretic activity and regulates local blood flow, glandular secretion, and smooth muscle activity. The peptide also stimulates feeding and drinking behavior and influences secretion of pituitary hormones.Dogs: The domestic dog, Canis familiaris, comprising about 400 breeds, of the carnivore family CANIDAE. They are worldwide in distribution and live in association with people. (Walker's Mammals of the World, 5th ed, p1065)Disease Progression: The worsening of a disease over time. This concept is most often used for chronic and incurable diseases where the stage of the disease is an important determinant of therapy and prognosis.Sodium Chloride Symporter Inhibitors: Agents that inhibit SODIUM CHLORIDE SYMPORTERS. They act as DIURETICS. Excess use is associated with HYPOKALEMIA.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.Incidence: The number of new cases of a given disease during a given period in a specified population. It also is used for the rate at which new events occur in a defined population. It is differentiated from PREVALENCE, which refers to all cases, new or old, in the population at a given time.Bone Morphogenetic Protein Receptors, Type II: A subtype of bone morphogenetic protein receptors with low affinity for BONE MORPHOGENETIC PROTEINS. They are constitutively active PROTEIN-SERINE-THREONINE KINASES that can interact with and phosphorylate TYPE I BONE MORPHOGENETIC PROTEIN RECEPTORS.Risk Assessment: The qualitative or quantitative estimation of the likelihood of adverse effects that may result from exposure to specified health hazards or from the absence of beneficial influences. (Last, Dictionary of Epidemiology, 1988)Body Mass Index: An indicator of body density as determined by the relationship of BODY WEIGHT to BODY HEIGHT. BMI=weight (kg)/height squared (m2). BMI correlates with body fat (ADIPOSE TISSUE). Their relationship varies with age and gender. For adults, BMI falls into these categories: below 18.5 (underweight); 18.5-24.9 (normal); 25.0-29.9 (overweight); 30.0 and above (obese). (National Center for Health Statistics, Centers for Disease Control and Prevention)Technetium: The first artificially produced element and a radioactive fission product of URANIUM. Technetium has the atomic symbol Tc, atomic number 43, and atomic weight 98.91. All technetium isotopes are radioactive. Technetium 99m (m=metastable) which is the decay product of Molybdenum 99, has a half-life of about 6 hours and is used diagnostically as a radioactive imaging agent. Technetium 99 which is a decay product of technetium 99m, has a half-life of 210,000 years.Reflex: An involuntary movement or exercise of function in a part, excited in response to a stimulus applied to the periphery and transmitted to the brain or spinal cord.Tomography, X-Ray Computed: Tomography using x-ray transmission and a computer algorithm to reconstruct the image.SulfonesBiological Markers: Measurable and quantifiable biological parameters (e.g., specific enzyme concentration, specific hormone concentration, specific gene phenotype distribution in a population, presence of biological substances) which serve as indices for health- and physiology-related assessments, such as disease risk, psychiatric disorders, environmental exposure and its effects, disease diagnosis, metabolic processes, substance abuse, pregnancy, cell line development, epidemiologic studies, etc.Diastole: Post-systolic relaxation of the HEART, especially the HEART VENTRICLES.RNA, Messenger: RNA sequences that serve as templates for protein synthesis. Bacterial mRNAs are generally primary transcripts in that they do not require post-transcriptional processing. Eukaryotic mRNA is synthesized in the nucleus and must be exported to the cytoplasm for translation. Most eukaryotic mRNAs have a sequence of polyadenylic acid at the 3' end, referred to as the poly(A) tail. The function of this tail is not known for certain, but it may play a role in the export of mature mRNA from the nucleus as well as in helping stabilize some mRNA molecules by retarding their degradation in the cytoplasm.Echocardiography: Ultrasonic recording of the size, motion, and composition of the heart and surrounding tissues. The standard approach is transthoracic.