Regional Blood Flow: The flow of BLOOD through or around an organ or region of the body.Microspheres: Small uniformly-sized spherical particles, of micrometer dimensions, frequently labeled with radioisotopes or various reagents acting as tags or markers.Blood Flow Velocity: A value equal to the total volume flow divided by the cross-sectional area of the vascular bed.Cardiac Output: The volume of BLOOD passing through the HEART per unit of time. It is usually expressed as liters (volume) per minute so as not to be confused with STROKE VOLUME (volume per beat).Cerebrovascular Circulation: The circulation of blood through the BLOOD VESSELS of the BRAIN.Hemodynamics: The movement and the forces involved in the movement of the blood through the CARDIOVASCULAR SYSTEM.Blood Circulation: The movement of the BLOOD as it is pumped through the CARDIOVASCULAR SYSTEM.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.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)Coronary Circulation: The circulation of blood through the CORONARY VESSELS of the HEART.Splanchnic Circulation: The circulation of blood through the BLOOD VESSELS supplying the abdominal VISCERA.Blood Pressure: PRESSURE of the BLOOD on the ARTERIES and other BLOOD VESSELS.Scandium: Scandium. An element of the rare earth family of metals. It has the atomic symbol Sc, atomic number 21, and atomic weight 45.Renal Circulation: The circulation of the BLOOD through the vessels of the KIDNEY.Liver Circulation: The circulation of BLOOD through the LIVER.Pulmonary Circulation: The circulation of the BLOOD through the LUNGS.Laser-Doppler Flowmetry: A method of non-invasive, continuous measurement of MICROCIRCULATION. The technique is based on the values of the DOPPLER EFFECT of low-power laser light scattered randomly by static structures and moving tissue particulates.Xenon Radioisotopes: Unstable isotopes of xenon that decay or disintegrate emitting radiation. Xe atoms with atomic weights 121-123, 125, 127, 133, 135, 137-145 are radioactive xenon isotopes.Heart Rate: The number of times the HEART VENTRICLES contract per unit of time, usually per minute.Anesthesia: A state characterized by loss of feeling or sensation. This depression of nerve function is usually the result of pharmacologic action and is induced to allow performance of surgery or other painful procedures.Oxygen: An element with atomic symbol O, atomic number 8, and atomic weight [15.99903; 15.99977]. It is the most abundant element on earth and essential for respiration.Blood Gas Analysis: Measurement of oxygen and carbon dioxide in the blood.Radioisotopes: Isotopes that exhibit radioactivity and undergo radioactive decay. (From Grant & Hackh's Chemical Dictionary, 5th ed & McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Nafronyl: A drug used in the management of peripheral and cerebral vascular disorders. It is claimed to enhance cellular oxidative capacity and to be a spasmolytic. (From Martindale, The Extra Pharmacopoeia, 30th ed, p1310) It may also be an antagonist at 5HT-2 serotonin receptors.Oxygen Consumption: The rate at which oxygen is used by a tissue; microliters of oxygen STPD used per milligram of tissue per hour; the rate at which oxygen enters the blood from alveolar gas, equal in the steady state to the consumption of oxygen by tissue metabolism throughout the body. (Stedman, 25th ed, p346)Nitrogen Radioisotopes: Unstable isotopes of nitrogen that decay or disintegrate emitting radiation. N atoms with atomic weights 12, 13, 16, 17, and 18 are radioactive nitrogen isotopes.Tomography, Emission-Computed: Tomography using radioactive emissions from injected RADIONUCLIDES and computer ALGORITHMS to reconstruct an image.Phentolamine: A nonselective alpha-adrenergic antagonist. It is used in the treatment of hypertension and hypertensive emergencies, pheochromocytoma, vasospasm of RAYNAUD DISEASE and frostbite, clonidine withdrawal syndrome, impotence, and peripheral vascular disease.Ventilation-Perfusion Ratio: The ratio of alveolar ventilation to simultaneous alveolar capillary blood flow in any part of the lung. (Stedman, 25th ed)Oxygen Radioisotopes: Unstable isotopes of oxygen that decay or disintegrate emitting radiation. O atoms with atomic weights 13, 14, 15, 19, and 20 are radioactive oxygen isotopes.Kidney: Body organ that filters blood for the secretion of URINE and that regulates ion concentrations.Brain: The part of CENTRAL NERVOUS SYSTEM that is contained within the skull (CRANIUM). Arising from the NEURAL TUBE, the embryonic brain is comprised of three major parts including PROSENCEPHALON (the forebrain); MESENCEPHALON (the midbrain); and RHOMBENCEPHALON (the hindbrain). The developed brain consists of CEREBRUM; CEREBELLUM; and other structures in the BRAIN STEM.Swine: Any of various animals that constitute the family Suidae and comprise stout-bodied, short-legged omnivorous mammals with thick skin, usually covered with coarse bristles, a rather long mobile snout, and small tail. Included are the genera Babyrousa, Phacochoerus (wart hogs), and Sus, the latter containing the domestic pig (see SUS SCROFA).Hindlimb: Either of two extremities of four-footed non-primate land animals. It usually consists of a FEMUR; TIBIA; and FIBULA; tarsals; METATARSALS; and TOES. (From Storer et al., General Zoology, 6th ed, p73)Carbon Dioxide: A colorless, odorless gas that can be formed by the body and is necessary for the respiration cycle of plants and animals.Microcirculation: The circulation of the BLOOD through the MICROVASCULAR NETWORK.Organotechnetium Compounds: Organic compounds that contain technetium as an integral part of the molecule. These compounds are often used as radionuclide imaging agents.Immersion: The placing of a body or a part thereof into a liquid.Vasoconstriction: The physiological narrowing of BLOOD VESSELS by contraction of the VASCULAR SMOOTH MUSCLE.Partial Pressure: The pressure that would be exerted by one component of a mixture of gases if it were present alone in a container. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)Models, Cardiovascular: Theoretical representations that simulate the behavior or activity of the cardiovascular system, processes, or phenomena; includes the use of mathematical equations, computers and other electronic equipment.Iliac Artery: Either of two large arteries originating from the abdominal aorta; they supply blood to the pelvis, abdominal wall and legs.Blood Volume: Volume of circulating BLOOD. It is the sum of the PLASMA VOLUME and ERYTHROCYTE VOLUME.Renal Artery: A branch of the abdominal aorta which supplies the kidneys, adrenal glands and ureters.Ischemia: 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.Vasodilation: The physiological widening of BLOOD VESSELS by relaxing the underlying VASCULAR SMOOTH MUSCLE.Pulmonary Gas Exchange: The exchange of OXYGEN and CARBON DIOXIDE between alveolar air and pulmonary capillary blood that occurs across the BLOOD-AIR BARRIER.Vasodilator Agents: Drugs used to cause dilation of the blood vessels.Supine Position: The posture of an individual lying face up.Anesthesia, Inhalation: Anesthesia caused by the breathing of anesthetic gases or vapors or by insufflating anesthetic gases or vapors into the respiratory tract.Time Factors: Elements of limited time intervals, contributing to particular results or situations.NG-Nitroarginine Methyl Ester: A non-selective inhibitor of nitric oxide synthase. It has been used experimentally to induce hypertension.Heart: The hollow, muscular organ that maintains the circulation of the blood.Collateral Circulation: Maintenance of blood flow to an organ despite obstruction of a principal vessel. Blood flow is maintained through small vessels.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.Isoflurane: A stable, non-explosive inhalation anesthetic, relatively free from significant side effects.Leg: The inferior part of the lower extremity between the KNEE and the ANKLE.Infusions, Parenteral: The administration of liquid medication, nutrient, or other fluid through some other route than the alimentary canal, usually over minutes or hours, either by gravity flow or often by infusion pumping.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.Mesenteric Arteries: Arteries which arise from the abdominal aorta and distribute to most of the intestines.Cats: The domestic cat, Felis catus, of the carnivore family FELIDAE, comprising over 30 different breeds. The domestic cat is descended primarily from the wild cat of Africa and extreme southwestern Asia. Though probably present in towns in Palestine as long ago as 7000 years, actual domestication occurred in Egypt about 4000 years ago. (From Walker's Mammals of the World, 6th ed, p801)Flow Cytometry: Technique using an instrument system for making, processing, and displaying one or more measurements on individual cells obtained from a cell suspension. Cells are usually stained with one or more fluorescent dyes specific to cell components of interest, e.g., DNA, and fluorescence of each cell is measured as it rapidly transverses the excitation beam (laser or mercury arc lamp). Fluorescence provides a quantitative measure of various biochemical and biophysical properties of the cell, as well as a basis for cell sorting. Other measurable optical parameters include light absorption and light scattering, the latter being applicable to the measurement of cell size, shape, density, granularity, and stain uptake.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.Propranolol: A widely used non-cardioselective beta-adrenergic antagonist. Propranolol has been used for MYOCARDIAL INFARCTION; ARRHYTHMIA; ANGINA PECTORIS; HYPERTENSION; HYPERTHYROIDISM; MIGRAINE; PHEOCHROMOCYTOMA; and ANXIETY but adverse effects instigate replacement by newer drugs.Tomography, Emission-Computed, Single-Photon: A method of computed tomography that uses radionuclides which emit a single photon of a given energy. The camera is rotated 180 or 360 degrees around the patient to capture images at multiple positions along the arc. The computer is then used to reconstruct the transaxial, sagittal, and coronal images from the 3-dimensional distribution of radionuclides in the organ. The advantages of SPECT are that it can be used to observe biochemical and physiological processes as well as size and volume of the organ. The disadvantage is that, unlike positron-emission tomography where the positron-electron annihilation results in the emission of 2 photons at 180 degrees from each other, SPECT requires physical collimation to line up the photons, which results in the loss of many available photons and hence degrades the image.Forearm: Part of the arm in humans and primates extending from the ELBOW to the WRIST.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.Muscle, Skeletal: A subtype of striated muscle, attached by TENDONS to the SKELETON. Skeletal muscles are innervated and their movement can be consciously controlled. They are also called voluntary muscles.Sheep: Any of the ruminant mammals with curved horns in the genus Ovis, family Bovidae. They possess lachrymal grooves and interdigital glands, which are absent in GOATS.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.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.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.Injections, Intravenous: Injections made into a vein for therapeutic or experimental purposes.Nitric Oxide Synthase: An NADPH-dependent enzyme that catalyzes the conversion of L-ARGININE and OXYGEN to produce CITRULLINE and NITRIC OXIDE.Pulsatile Flow: Rhythmic, intermittent propagation of a fluid through a BLOOD VESSEL or piping system, in contrast to constant, smooth propagation, which produces laminar flow.Rabbits: The species Oryctolagus cuniculus, in the family Leporidae, order LAGOMORPHA. Rabbits are born in burrows, furless, and with eyes and ears closed. In contrast with HARES, rabbits have 22 chromosome pairs.Dose-Response Relationship, Drug: The relationship between the dose of an administered drug and the response of the organism to the drug.Coronary Vessels: The veins and arteries of the HEART.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.Magnetic Resonance Imaging: Non-invasive method of demonstrating internal anatomy based on the principle that atomic nuclei in a strong magnetic field absorb pulses of radiofrequency energy and emit them as radiowaves which can be reconstructed into computerized images. The concept includes proton spin tomographic techniques.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.Arteries: The vessels carrying blood away from the heart.Lung: Either of the pair of organs occupying the cavity of the thorax that effect the aeration of the blood.Myocardial Contraction: Contractile activity of the MYOCARDIUM.Capillaries: The minute vessels that connect the arterioles and venules.Blood DonorsEnzyme Inhibitors: Compounds or agents that combine with an enzyme in such a manner as to prevent the normal substrate-enzyme combination and the catalytic reaction.Myocardial Infarction: NECROSIS of the MYOCARDIUM caused by an obstruction of the blood supply to the heart (CORONARY CIRCULATION).Coronary Disease: An imbalance between myocardial functional requirements and the capacity of the CORONARY VESSELS to supply sufficient blood flow. It is a form of MYOCARDIAL ISCHEMIA (insufficient blood supply to the heart muscle) caused by a decreased capacity of the coronary vessels.Rheology: The study of the deformation and flow of matter, usually liquids or fluids, and of the plastic flow of solids. The concept covers consistency, dilatancy, liquefaction, resistance to flow, shearing, thixotrophy, and VISCOSITY.Anoxia: Relatively complete absence of oxygen in one or more tissues.Hyperemia: The presence of an increased amount of blood in a body part or an organ leading to congestion or engorgement of blood vessels. Hyperemia can be due to increase of blood flow into the area (active or arterial), or due to obstruction of outflow of blood from the area (passive or venous).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)Xenon: A noble gas with the atomic symbol Xe, atomic number 54, and atomic weight 131.30. It is found in the earth's atmosphere and has been used as an anesthetic.Gene Flow: The change in gene frequency in a population due to migration of gametes or individuals (ANIMAL MIGRATION) across population barriers. In contrast, in GENETIC DRIFT the cause of gene frequency changes are not a result of population or gamete movement.Blood Circulation Time: Determination of the shortest time interval between the injection of a substance in the vein and its arrival at some distant site in sufficient concentration to produce a recognizable end result. It represents approximately the inverse of the average velocity of blood flow between two points.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.Plethysmography: Recording of change in the size of a part as modified by the circulation in it.Posture: The position or attitude of the body.Cerebral Arteries: The arterial blood vessels supplying the CEREBRUM.Contrast Media: Substances used to allow enhanced visualization of tissues.Ultrasonography, Doppler, Transcranial: A non-invasive technique using ultrasound for the measurement of cerebrovascular hemodynamics, particularly cerebral blood flow velocity and cerebral collateral flow. With a high-intensity, low-frequency pulse probe, the intracranial arteries may be studied transtemporally, transorbitally, or from below the foramen magnum.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.Middle Cerebral Artery: The largest of the cerebral arteries. It trifurcates into temporal, frontal, and parietal branches supplying blood to most of the parenchyma of these lobes in the CEREBRAL CORTEX. These are the areas involved in motor, sensory, and speech activities.Retinal Vessels: The blood vessels which supply and drain the RETINA.Antipyrine: An analgesic and antipyretic that has been given by mouth and as ear drops. Antipyrine is often used in testing the effects of other drugs or diseases on drug-metabolizing enzymes in the liver. (From Martindale, The Extra Pharmacopoeia, 30th ed, p29)Perfusion: Treatment process involving the injection of fluid into an organ or tissue.Choroid: The thin, highly vascular membrane covering most of the posterior of the eye between the RETINA and SCLERA.Skin Temperature: The TEMPERATURE at the outer surface of the body.Vasomotor System: The neural systems which act on VASCULAR SMOOTH MUSCLE to control blood vessel diameter. The major neural control is through the sympathetic nervous system.Femoral Artery: The main artery of the thigh, a continuation of the external iliac artery.Brain Ischemia: Localized reduction of blood flow to brain tissue due to arterial obstruction or systemic hypoperfusion. This frequently occurs in conjunction with brain hypoxia (HYPOXIA, BRAIN). Prolonged ischemia is associated with BRAIN INFARCTION.Skin: The outer covering of the body that protects it from the environment. It is composed of the DERMIS and the EPIDERMIS.Adenosine: A nucleoside that is composed of ADENINE and D-RIBOSE. Adenosine or adenosine derivatives play many important biological roles in addition to being components of DNA and RNA. Adenosine itself is a neurotransmitter.

Intrarenal site of action of calcium on renin secretion in dogs. (1/9283)

We studied the effects of intrarenal calcium infusion on renin secretion in sodium-depleted dogs in an attempt to elucidate the major site of calcium-induced inhibition of renin release. Both calcium chloride and calcium gluconate reduced renal blood flow and renin secretion while renal perfusion pressure was unchanged. These data indicate that calcium inhibition of renin secretion did not occur primarily at the renal vascular receptor; decreased renal blood flow is usually associated with increased renin secretion. Calcium chloride infusion increased urinary chloride excretion without affecting sodium excretion, and calcium gluconate failed to increase either sodium or chloride excretion. Also, the filtered loads of sodium and chloride were unchanged during the calcium infusions. These results give no indication that calcium inhibited renin secretion by increasing the sodium or chloride load at the macula densa. The effects of intrarenal calcium infusion on renin release were also assessed in dogs with a nonfiltering kidney in which renal tubular mechanisms could not influence renin secretion. The observation that calcium still suppressed renin release in these dogs provides additional evidence that the the major effect of calcium involved nontubular mechanisms. Thus, it appears likely that calcium acted directly on the juxtaglomerular cells to inhibit renin secretion.  (+info)

Vascular remodeling in response to altered blood flow is mediated by fibroblast growth factor-2. (2/9283)

Vascular structures adapt to changes in blood flow by adjusting their diameter accordingly. The factors mediating this process are only beginning to be identified. We have recently established a mouse model of arterial remodeling in which flow in the common carotid artery is interrupted by ligation of the vessel near the carotid bifurcation, resulting in a dramatic reduction in vessel diameter as a consequence of inward remodeling and intimal lesion formation. In the present study, we used this model to determine the role of fibroblast growth factor-2 (FGF-2) in the remodeling response by maintaining neutralizing serum levels of a mouse monoclonal antibody against FGF-2 for 4 weeks. Morphometric analysis revealed that intimal lesion formation was not affected by the antibody. However, lumen narrowing was significantly inhibited, resulting in a greater than 3-fold increase in lumen area in anti-FGF-2-treated animals compared with controls. Treatment with anti-FGF-2 antibody significantly inhibited the reduction in vessel diameter (inward remodeling) and shortening of the internal elastic lamina in the ligated vessel. In addition, anti-FGF-2 treatment also caused outward remodeling of the contralateral carotid artery. These findings identify FGF-2 as an important factor in vascular remodeling, and its effects are likely to be mediated by increasing vascular tone. The results are consistent with the recent observation of reduced vascular tone in the FGF-2-deficient mouse.  (+info)

Role of endothelin in the increased vascular tone of patients with essential hypertension. (3/9283)

We investigated the possible role of endothelin in the increased vasoconstrictor tone of hypertensive patients using antagonists of endothelin receptors. Forearm blood flow (FBF) responses (strain-gauge plethysmography) to intraarterial infusion of blockers of endothelin-A (ETA) (BQ-123) and endothelin-B (ETB) (BQ-788) receptors, separately and in combination, were measured in hypertensive patients and normotensive control subjects. In healthy subjects, BQ-123 alone or in combination with BQ-788 did not significantly modify FBF (P=0.78 and P=0.63, respectively). In hypertensive patients, in contrast, BQ-123 increased FBF by 33+/-7% (P<0.001 versus baseline), and the combination of BQ-123 and BQ-788 resulted in a greater vasodilator response (63+/-12%; P=0.006 versus BQ-123 alone in the same subjects). BQ-788 produced a divergent vasoactive effect in the two groups, with a decrease of FBF (17+/-5%; P=0.004 versus baseline) in control subjects and transient vasodilation (15+/-7% after 20 minutes) in hypertensive patients (P<0.001, hypertensives versus controls). The vasoconstrictor response to endothelin-1 was slightly higher (P=0.04) in hypertensive patients (46+/-4%) than in control subjects (32+/-4%). Our data indicate that patients with essential hypertension have increased vascular endothelin activity, which may be of pathophysiological relevance to their increased vascular tone. In these patients, nonselective ETA and ETB blockade seems to produce a greater vasodilator effect than selective ETA blockade.  (+info)

Bronchial artery perfusion scintigraphy to assess bronchial artery blood flow after lung transplantation. (4/9283)

The bronchial arterial system is inevitably interrupted in transplanted lungs when removing the organs from the donor, but it can be reestablished by direct bronchial artery revascularization (BAR) during implantation. The purpose of this study was to visualize and quantify the distribution of bronchial artery perfusion after en bloc double lung transplantation with BAR, by injecting radiolabeled macroaggregated albumin directly into the bronchial artery system. METHODS: BAR was performed using the internal mammary artery as conduit. Patients were imaged 1 mo (n = 13) or 2 y (n = 9) after en bloc double lung transplantation with BAR. Immediately after bronchial arteriography, 100 MBq macroaggregated albumin (45,000 particles) were injected through the arteriographic catheter. Gamma camera studies were then acquired in the anterior position. At the end of imaging, with the patient remaining in exactly the same position, 81mKr-ventilation scintigraphy or conventional intravenous pulmonary perfusion scintigraphy or both were performed. Images were evaluated by visual analysis, and a semiquantitative assessment of the bronchial arterial supply to the peripheral parts of the lungs was obtained with conventional pulmonary scintigraphy. RESULTS: The bronchial artery scintigraphic images showed that the major part of the bronchial arterial flow supplied central thoracic structures, but bronchial artery perfusion could also be demonstrated in the peripheral parts of the lungs when compared with conventional pulmonary scintigraphy. There were no differences between scintigrams obtained from patients studied 1 mo and 2 y post-transplantation. CONCLUSION: Total distribution of bronchial artery supply to the human lung has been visualized in lung transplant patients. This study demonstrates that this nutritive flow reaches even the most peripheral parts of the lungs and is present 1 mo as well as 2 y after lung transplantation. The results suggest that bronchial artery revascularization may be of significance for the long-term status of the lung transplant.  (+info)

Pulsed Doppler ultrasonographic evaluation of portal blood flow in dogs with experimental portal vein branch ligation. (5/9283)

Portal blood flow was measured using pulsed Doppler ultrasound in 6 dogs before and after left portal vein branch ligation. Mean portal vein blood flow velocity and mean portal vein blood flow were significantly reduced after ligation and the congestion index was increased (p < 0.01). Pulsed Doppler ultrasound studies provide valuable physiological information which may assist the clinician with the diagnosis of canine hepatic circulatory disorders.  (+info)

Rescue of diabetes-related impairment of angiogenesis by intramuscular gene therapy with adeno-VEGF. (6/9283)

Diabetes is a major risk factor for coronary and peripheral artery diseases. Although diabetic patients often present with advanced forms of these diseases, it is not known whether the compensatory mechanisms to vascular ischemia are affected in this condition. Accordingly, we sought to determine whether diabetes could: 1) impair the development of new collateral vessel formation in response to tissue ischemia and 2) inhibit cytokine-induced therapeutic neovascularization. Hindlimb ischemia was created by femoral artery ligation in nonobese diabetic mice (NOD mice, n = 20) and in control C57 mice (n = 20). Hindlimb perfusion was evaluated by serial laser Doppler studies after the surgery. In NOD mice, measurement of the Doppler flow ratio between the ischemic and the normal limb indicated that restoration of perfusion in the ischemic hindlimb was significantly impaired. At day 14 after surgery, Doppler flow ratio in the NOD mice was 0.49+/-0.04 versus 0.73+/-0.06 for the C57 mice (P< or =0.005). This impairment in blood flow recovery persisted throughout the duration of the study with Doppler flow ratio values at day 35 of 0.50+/-0.05 versus 0.90+/-0.07 in the NOD and C57 mice, respectively (P< or =0.001). CD31 immunostaining confirmed the laser Doppler data by showing a significant reduction in capillary density in the NOD mice at 35 days after surgery (302+/-4 capillaries/mm2 versus 782+/-78 in C57 mice (P< or =0.005). The reduction in neovascularization in the NOD mice was the result of a lower level of vascular endothelial growth factor (VEGF) in the ischemic tissues, as assessed by Northern blot, Western blot and immunohistochemistry. The central role of VEGF was confirmed by showing that normal levels of neovascularization (compared with C57) could be achieved in NOD mice that had been supplemented for this growth factor via intramuscular injection of an adenoviral vector encoding for VEGF. We conclude that 1) diabetes impairs endogenous neovascularization of ischemic tissues; 2) the impairment in new blood vessel formation results from reduced expression of VEGF; and 3) cytokine supplementation achieved by intramuscular adeno-VEGF gene transfer restores neovascularization in a mouse model of diabetes.  (+info)

Sonographic evidence for the involvement of the utero-ovarian counter-current system in the ovarian control of directed uterine sperm transport. (7/9283)

Sperm transport from the cervix into the tube is an important uterine function within the process of reproduction. This function is exerted by uterine peristalsis and is controlled by the dominant ovarian structure via a cascade of endocrine events. The uterine peristaltic activity involves only the stratum subvasculare of the myometrium, which exhibits a predominantly circular arrangement of muscular fibres that separate at the fundal level into the fibres of the cornua and continue into the circular muscles of the respective tubes. Since spermatozoa are transported preferentially into the tube ipsilateral to the dominant follicle, this asymmetric uterine function may be controlled by the ovary via direct effects utilizing the utero-ovarian counter-current system, in addition to the systemic circulation. To test this possibility the sonographic characteristics of the uterine vascular bed were studied during different phases of the menstrual cycle. Vaginal sonography with the measurement of Doppler flow characteristics of both uterine arteries and of the arterial anastomoses of the uterine and ovarian arteries (junctional vessels) in the cornual region of both sides of the uterus during the menstrual phase of regular-cycling women demonstrated significant lower resistance indices of the junctional vessels ipsilateral to the side of the dominant ovarian structure as compared with the corresponding arteries contralaterally. By the use of the perfusion mode technique, it could be observed that vascular perfusion of the fundal myometrium was significantly increased ipsilateral to the dominant follicle during the late follicular phase of the cycle. These results show that the endocrine control of the dominant ovarian structure over uterine function is not only exerted via the systemic circulation but also directly, most probably utilizing the utero-ovarian counter-current system.  (+info)

Endothelial function in Marfan syndrome: selective impairment of flow-mediated vasodilation. (8/9283)

BACKGROUND: The cardiovascular complications of Marfan syndrome arise due to alterations in the structural and functional properties of fibrillin, a constituent of vascular connective tissues. Fibrillin-containing microfibrils are closely associated with arterial endothelial cells, indicating a possible functional role for fibrillin in the endothelium. Plasma concentrations of endothelial cell products are elevated in Marfan subjects, which indirectly indicates endothelial dysfunction. This study directly assessed flow- and agonist-mediated endothelium-dependent brachial artery reactivity in Marfan subjects. METHODS AND RESULTS: In 20 Marfan and 20 control subjects, brachial artery diameter, blood flow, and blood pressure were measured by ultrasonic wall tracking, Doppler ultrasound, and photoplethysmography, respectively. Measurements were taken during hand hyperemia (a stimulus for endothelium-derived nitric oxide [NO] release in the upstream brachial artery) and after sublingual administration of the endothelium-independent vasodilator nitroglycerin. In 9 Marfan and 6 control subjects, the above parameters were also assessed during intra-arterial infusions of acetylcholine and bradykinin (agonists that stimulate NO production) and NG-monomethyl-L-arginine (L-NMMA, an inhibitor of NO production). Flow-mediated responses differed markedly between Marfan and control subjects (-1.6+/-3.5% versus 6. 50+/-4.1%, respectively; P<0.0001), whereas nitroglycerin produced similar vasodilation (14.2+/-5.7% versus 15.2+/-7.8%; P=NS). Agonist-induced vasodilation to incremental intra-arterial infusions of acetylcholine and bradykinin were not significantly different between Marfan and control subjects, and intra-arterial L-NMMA produced similar reductions in brachial artery diameter in both groups. CONCLUSIONS: These data demonstrate impaired flow-mediated but preserved agonist-mediated endothelium-dependent vasodilation in Marfan subjects and suggest preservation of basal NO release. Selective loss of flow-mediated dilation suggests a role for fibrillin in endothelial cell mechanotransduction.  (+info)

  • abstract = "The effect of bolus intravenous injections of amrinone (1-2 mg/kg) on abdominal organ, central nervous system, and myocardial blood flow distribution was examined in 15 anesthetized dogs. (umn.edu)
  • No significant alterations were found in regional cortical perfusion, indicating that the increased binding index was not a consequence of increased tracer delivery. (ugent.be)
  • Recently, short-term visual deprivation has been shown to affect a variety of non-visual processes and regional cortical activity (Sathian & Zangaladze, 2001). (arvojournals.org)
  • To keep up with the nutritional and waste removal demands of a higher metabolic rate, cerebral blood flow to the cortical area in use must increase proportionally. (wikipedia.org)
  • Photoelectric cells in a spectrophotometer device worn on the forehead measure the amount of each wavelength of light reflected by cerebral blood flow in the activated cortical tissue and send the data to a computer, which then calculates the ratio of red to infrared light and translates it into a visual signal of corresponding to oxygenation level on a graphical interface the patient can see. (wikipedia.org)
  • mean +/- SD) on regional cerebral blood flow and cerebral volume was studied in a group of ten right-handed patients with Type 1 (insulin-dependent) diabetes mellitus (age 26.0 +/- 2.4 years, duration 18.4 +/- 3.8 years) using an intravenous Xenon 133 single photon emission computed tomography technique. (lu.se)
  • Dynamic computed tomography, digital subtraction angiography, and radionuclide angiography can all be used to evaluate regional blood flow noninvasively. (semanticscholar.org)
  • Ten patients with a presenile (before 65 years old) onset of the disease and 16 with senile onset of the disease were evaluated clinically and neuropsychologically and studied with single photon emission computed tomography using the blood flow tracer [ 123 I] N -isopropyl-p-iodoamphetamine. (jamanetwork.com)
  • These results provide baseline values for regional blood flow during CPR which can be used to evaluate alternative CPR techniques and/or drugs which may improve perfusion of vital organs during CPR. (purdue.edu)
  • Single-photon emission tomography (SPET) was used to measure regional brain perfusion using technetium-99m labelled ethyl cysteinate dimer (ECD). (ugent.be)
  • This study aims to evaluate changes in regional metabolism and cerebral perfusion in subjects who used methamphetamine (METH) prior to sustaining a TBI. (elsevier.com)
  • intestinal, gastric mucosal, gallbladder, and triceps flows were reduced by values ranging from 26.7 to 38.9% and central nervous system perfusion was reduced by values ranging from 11.8 to 19.4% in all regions except the caudate nucleus. (umn.edu)
  • Hepatic blood perfusion can be measured by dynamic PET using tracers for which the permeability of the plasma-hepatocyte membrane is high. (benthamscience.com)
  • Two indexes of cerebral perfusion, a ratio of regional flow compared with occipital flow and a left-right asymmetry index, demonstrated relative left frontal hypoperfusion in presenile- but not senile-onset patients and did not appear to be an artifact of the severity differences. (jamanetwork.com)
  • Local skin blood flow (LSBF) using the Walker's deep burn rat model was studied on the first three postburn days using the carbon-14 iodoantipyrine ([ 14 C]IAP) perfusion method. (elsevier.com)
  • In the rat, renal (14), mesenteric and aortic flows (15) were measured with Transonic probes and compared with known blood/saline flows obtained from pump-perfused circuits (15) or by clearance of p-aminohippuric acid (14). (scielo.br)
  • It was found that blood flow during CPR is highly dependent on venous valving and aortic valve competence. (elsevier.com)
  • When the ovine fetus is exposed to asphyxia of sufficient severity to produce neurologic damage (seizures), the pattern of redistribution of blood flow is comparable to the response to lesser asphyxia, except that a significant increase in total brain blood flow does not occur. (nih.gov)
  • In Brain and Blood Flow , R. W. Ross Russell, ed. (springer.com)
  • A detailed examination of the regional distribution of cerebral blood flow revealed that almost all brain regions were hyperperfused during diving. (biologists.org)
  • Accordingly, we tested whether neuropsychological function and brain blood flow responses to cognitive challenges among prehypertensive individuals would predict subsequent progression of BP. (ahajournals.org)
  • Cerebral blood flow (CBF) is critical for the maintenance of cerebral function by guaranteed constant oxygen and glucose supply to brain. (spiedigitallibrary.org)
  • The ratios of regional blood flow during CPR to regional blood flow during sinus rhythm were 90% for brain, 35% for heart, 15% for kidneys, 17% for adrenal glands, 14% for pancreas, 3% for spleen, and 33% for small intestine. (purdue.edu)
  • There is a practical way to measure metabolism, flow, and function in a localized area of brain serially in the same animal. (ovid.com)
  • The secondary outcomes will be vasospasm measured by CT angiography, ischaemic parameters measured by brain microdialysis, flow velocities in the medial cerebral artery, clinical parameters and outcome (Glasgow Outcome Scale) at 3 months. (biomedcentral.com)
  • Importantly, despite a decreased cardiac output, relative blood flow to the head increased during diving, suggesting that there is maintenance of blood flow to the brain. (usask.ca)
  • The effects of two levels of fluid-percussion brain injury on cerebral blood flow (CBF) and pial arteriolar diameter were investigated in cats. (utmb.edu)
  • Kontos, H. A. / Effects of fluid-percussion brain injury on regional cerebral blood flow and pial arteriolar diameter . (utmb.edu)
  • Brain Function and Blood Flow" (PDF). (wikipedia.org)
  • By so doing, participants increase cerebral blood flow to a specified region of the brain, consequently increasing brain activity and performance on tasks involving that region of the brain. (wikipedia.org)
  • Similar to functional magnetic resonance imaging, which uses changes in the magnetic properties of blood resulting from oxygenation to form an image of brain activity, NIR utilizes the changes in blood translucence resulting from oxygenation to generate a signal that can be consciously manipulated in neurofeedback sessions. (wikipedia.org)
  • PIR uses a sensor similar to the NIR sensor to detect light from a narrow band of the infrared spectrum that corresponds to the amount of heat being generated by an active brain region, as well as the local blood oxygenation level. (wikipedia.org)
  • Discrepancies between radiographic findings and delayed ischemic deficits may depend on the relationship between local cerebral oxygen-requirement and -deliv-ery, which only can be determined if cerebral blood flow (CBF) and cerebral oxy-gen extraction can be estimated. (springer.com)
  • A decrease in the jugular bulb oxygen saturation (SjvO 2 ) may be useful only in detecting severe prox-imal cerebral vasospasm, leading to significant reduction of hemispheric blood flow. (springer.com)
  • The resting state fMRI BOLD (blood-oxygen-level-dependent) signal will be evaluated for 'Goodness-of-Fit' to the default mode network at Baseline, 1 week, and 6 and 12 months in AD participants and normal control participants. (clinicaltrials.gov)
  • Regional cerebral oxygen supply and utilization in dementia. (springer.com)
  • Changing dopaminergic activity through different pathways : consequences for renal sodium excretion, regional blood flow and oxygen tension in the rat. (diva-portal.org)
  • A model for the coupling between cerebral blood flow and oxygen metabolism during neural stimulation. (semanticscholar.org)
  • This investigation evaluated regional differences in blood flow and oxygen consumption and their relationship in exercised muscle during recovery from exhaustive exercise. (elsevier.com)
  • blood flow declined from 2.0 ± 0.5 to 1.4 ± 0.3 ml·100 g -1 ·min -1 , and oxygen consumption decreased from 0.21 ± 0.04 to 0.17 ± 0.02 ml·100 g - 1· min -1 . (elsevier.com)
  • In contrast, these gradients in blood flow and oxygen consumption diminished during recovery after exercise. (elsevier.com)
  • These changes became larger in the direction from proximal to distal portions: blood flow increased from 2.9 ± 0.7 to 3.9 ± 0.8 and oxygen consumption from 1.4 ± 0.1 to 1.8 ± 0.4 times resting values. (elsevier.com)
  • Along with the increase in flow, hemoglobin molecules in the blood, which are responsible for the transport and transference of oxygen to tissue throughout the body, must increase the amount of oxygen they deliver to the activated region of the cortex, resulting in a greater local blood oxygenation level. (wikipedia.org)
  • To correlate changes in fitness as measured by peak VO2 and anaerobic threshold during cardiopulmonary exercise testing with changes in endothelial derived vasodilators, skeletal muscle blood flow, and insulin sensitivity. (clinicaltrials.gov)
  • In contrast, exercise-induced reduction of renal flow was smaller and slower, with 18% and 25% decreases at mild and moderate exercise intensities. (scielo.br)
  • In the rat, transit-time flowmetry has been widely used to quantitate blood flow in gastric (11,12), renal (13,14), mesenteric (13,15), carotid (13), and femoral (13) arteries and in the aorta (13,15) but only under acute conditions. (scielo.br)
  • By arresting flow promptly after a short pulse of diffusible tracer, it is feasible to equate the tracer retained in the tissue (Cif) with that delivered by the blood. (ovid.com)
  • Until the development of the blood flow tracer HMPAO (hexamethylpropyleneamine oxime) there was no practical way to study regional cerebral blood flow during or soon after seizures. (gla.ac.uk)
  • Using near-infrared spectroscopy (NIRS) and the tracer indocyanine green (ICG), we quantified blood flow in calf muscle and around the Achilles tendon during plantar flexion (1-9 W). For comparison, blood flow in calf muscle was determined by dye dilution in combination with magnetic resonance imaging measures of muscle volume, and, for the peritendon region, blood flow was measured by (133)Xe washout. (ku.dk)
  • Vatner, S , Pagani, M & Rutherford, JD 1978, ' Effects of nitroglycerin on cardiac function and regional blood flow distribution in conscious dogs ', American Journal of Physiology - Heart and Circulatory Physiology , vol. 3, no. 3. (researchwithrutgers.com)
  • After decades of work with various biofeedback mechanisms, Toomim accidentally stumbled upon conscious control of cerebral blood flow in 1994. (wikipedia.org)
  • Simulated relationship between blood flow during the recovery and half recovery time of oxygenation in the 3 minutes cuff ischemia (blue line with rectangle) and in the 25%MVC handgrip exercise (red line with triangle) in the finger flexor muscle. (biomedcentral.com)
  • 0.05) occurred 15 min after normalization of the blood glucose level. (lu.se)
  • Iliac flow increased instantaneously at the beginning of mild exercise (from 12.03 ± 1.06 to 25.55 ± 3.89 ml/min at 15 s) and showed a smaller increase when exercise intensity increased further, reaching a plateau of 38.43 ± 1.92 ml/min at the 4th min of moderate exercise intensity. (scielo.br)
  • However, lowering blood pressure (BP) does not uniformly reverse cognitive decline, suggesting that high BP per se may not cause cognitive decline. (ahajournals.org)
  • The studies described in this Thesis were designed to investigate the patterns of cerebral blood flow (CBF) deficits that occur in Dementia of the Alzheimer Type (DAT) and relate them to performance on a variety of cognitive tasks. (gla.ac.uk)
  • Although the presenile subjects had more severe neuropsychological abnormalities in all realms of cognitive function, including language, and showed greater reductions in regional blood flow than the older patients, they were also more severely demented, thus complicating interpretation of the results. (jamanetwork.com)
  • 1 2 3 4 However, conflicting data regarding the accuracy of this method were recently presented by Harris and Bailey, 5 indicating that hypercapnia induced during general anesthesia made a very small increase in rSO 2 despite the more than doubling of the middle cerebral artery flow velocity. (ahajournals.org)
  • We propose that postural tachycardia is related to thoracic hypovolemia during orthostasis but that the patterns of peripheral blood flow relate to different mechanisms for thoracic hypovolemia. (physiology.org)
July-August 1986 - Volume 10 - Issue 4 : Journal of Computer Assisted Tomography
July-August 1986 - Volume 10 - Issue 4 : Journal of Computer Assisted Tomography (journals.lww.com)
August 2011 - Volume 36 - Issue 8 : Clinical Nuclear Medicine
August 2011 - Volume 36 - Issue 8 : Clinical Nuclear Medicine (journals.lww.com)
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Salina Regional Health Center: Blood Flow Restriction Training (ksn.com)
Measurements of the Insula Volume Using MRI | SpringerLink
Measurements of the Insula Volume Using MRI | SpringerLink (link.springer.com)
Youth at-risk for serious mental illness: methods of the PROCAN study | SpringerLink
Youth at-risk for serious mental illness: methods of the PROCAN study | SpringerLink (link.springer.com)
Functional anatomy of human procedural learning determined with regional cerebral blood flow and PET | Journal of Neuroscience
Functional anatomy of human procedural learning determined with regional cerebral blood flow and PET | Journal of Neuroscience (jneurosci.org)
Regional Differences in β-Adrenergic Effects on Local Cerebral Blood Flow and Adrenergic Innervation | SpringerLink
Regional Differences in β-Adrenergic Effects on Local Cerebral Blood Flow and Adrenergic Innervation | SpringerLink (link.springer.com)
Category:Blood - Wikimedia Commons
Category:Blood - Wikimedia Commons (commons.wikimedia.org)
WikiGenes
WikiGenes (wikigenes.org)
Increased frontal and paralimbic activation following ayahuasca , the pan-amazonian inebriant | SpringerLink
Increased frontal and paralimbic activation following ayahuasca , the pan-amazonian inebriant | SpringerLink (link.springer.com)
Substrate metabolism, hormone and cytokine levels and adipose tissue signalling in individuals with type 1 diabetes after...
Substrate metabolism, hormone and cytokine levels and adipose tissue signalling in individuals with type 1 diabetes after... (link.springer.com)
Migraine With Aura Inducing Characteristics and Effects on the Cerebral Arteries and Blood Flow by Hypoxia - Full Text View -...
Migraine With Aura Inducing Characteristics and Effects on the Cerebral Arteries and Blood Flow by Hypoxia - Full Text View -... (clinicaltrials.gov)
Cannabidiol Reduces the Anxiety Induced by Simulated Public Speaking in Treatment-Naïve Social Phobia Patients |...
Cannabidiol Reduces the Anxiety Induced by Simulated Public Speaking in Treatment-Naïve Social Phobia Patients |... (nature.com)
Neuroscience of sleep - Wikipedia
Neuroscience of sleep - Wikipedia (en.wikipedia.org)
Dream - Wikipedia
Dream - Wikipedia (en.wikipedia.org)
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Eicosanoid - Wikipedia (en.wikipedia.org)
Absorption of drugs: how drugs are absorbed in the body? ePharmacology | HubPages
Absorption of drugs: how drugs are absorbed in the body? ePharmacology | HubPages (hubpages.com)
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The Effect of Acetylcholine on Regional Myocardial O2 Consumption and Coronary Blood Flow in the Rabbit Heart | SpringerLink (link.springer.com)
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Anders Nymark Christensen - DTU (dtu.dk)
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Cerebral Physiology of the Aged: Influence of Circulatory Disorders | SpringerLink (link.springer.com)