By comparison, the brains connected to BrainEx and perfused showed "dramatic differences," Sestan said.
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To pull that off, McIntyre perfused a rabbit's vascular system with a chemical fixative called glutaraldehyde.
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"Within two to four hours, you have to have it re-perfused and working again," Dr. Bojovic said.
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So, while the skin and muscle are perfused at a higher rate, the kidneys are receiving a reduced blood supply.
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The doctors procured other organs that had been identified for donation while the heart was perfused with a cold solution and removed.
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Once family consent was obtained, a transplant team could quickly harvest organs, including the heart, while they were still being perfused with blood.
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And yet by all accounts, the longer Vrselja and Daniele perfused the pig brains, and the better they got at the process, the more brain cells were restored.
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Maybe the solution didn't lie in slices of brain, but in an entire brain, perfused the way Belanger was perfusing this one, with hemoglobin-rich fluid standing in for a preservative.
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The demonstration in the Yale morgue inspired Sestan, and with the help of his team, he set about obtaining all the relevant literature on perfusion, including a 1964 study involving dog brains that had been perfused with whole blood.
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In March 2018, Sestan met again with the N.I.H. Under the impression that everything he said would be kept confidential, he had put together a presentation on his experiment, and while the dozen or so attendees looked on, he clicked through a series of slides showing restored cells from the perfused brains.
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A control experiment was performed for each group, in which cells were perfused with isosmotic media.
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Similarly, vessels and organs perfused from the true lumen but distal to the dissection may be perfused to varying degrees. In the above example, if the aortic dissection extended from proximal to the left subclavian artery takeoff to the mid descending aorta, the common iliac arteries would be perfused from the true lumen distal to the dissection but would be at risk for malperfusion due to occlusion of the true lumen of the aorta by the false lumen.
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Dissections become threatening to the health of the organism when growth of the false lumen prevents perfusion of the true lumen and the end organs perfused by the true lumen. For example, in an aortic dissection, if the left subclavian artery orifice were distal to the origin of the dissection, then the left subclavian would be said to be perfused by the false lumen, while the left common carotid (and its end organ, the left hemisphere of the brain) if proximal to the dissection, would be perfused by the true lumen proximal to the dissection. MRI of an aortic dissection 1 Aorta descendens with dissection 2 Aorta isthmus Vessels and organs that are perfused from a false lumen may be well-perfused to varying degrees, from normal perfusion to no perfusion. In some cases, little to no end-organ damage or failure may be seen.
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Physicians typically recommend which detoxification treatment should be used to manage possible dysfunction involving highly perfused organs, such as the liver and kidney.
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A pulmonary shunt refers to the passage of deoxygenated blood from the right side of the heart to the left without participation in gas exchange in the pulmonary capillaries. It is a pathological condition that results when the alveoli of the lungs are perfused with blood as normal, but ventilation (the supply of air) fails to supply the perfused region. In other words, the ventilation/perfusion ratio (the ratio of air reaching the alveoli to blood perfusing them) is zero. A pulmonary shunt often occurs when the alveoli fill with fluid, causing parts of the lung to be unventilated although they are still perfused.
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Therefore, its possible for the cilio retinal artery itself to occlude causing significant visual loss in the perfused macula region (surrounding visual field will remain intact).
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If the organ perfused by an artery is sensitive to even temporary occlusion of blood flow, such as in the brain, various other measures are taken.
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Riviere JE et al. The isolated perfused porcine skin flap (IPPSF). I. A novel in vitro model for percutaneous absorption and cutaneous toxicology studies. Fundam Appl Toxicol.
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There is evidence that immunological mechanisms may injure hypothermically perfused kidneys after reimplantation if the perfusate contained specific antibody. Cross described two pairs of human cadaver kidneys that were perfused simultaneously with cryoprecipitated plasma containing type specific HLA antibody to one of the pairs. Both these kidneys suffered early arterial thrombosis. Light described similar hyperacute rejection following perfusion storage and showed that the cryoprecipitated plasma used contained cytotoxic IgM antibody.
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Skin biopsies of affected extremities are rarely performed because of the frequent concern that a biopsy site near an area poorly perfused with blood will not heal well.
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Vascular recruitment is the increase in the number of perfused capillaries in response to a stimulus. I.e., the more you exercise regularly, the more oxygen can reach your muscles.
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The Yasui procedure includes a modified Damus–Kaye–Stansel procedure to connect the aortic and pulmonary roots, allowing the coronary arteries to remain perfused. It was first described in 1987.
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Moreover, most established neuroanatomical substrates for brain function are perfused by the major cerebral arteries that could be directly insonated. Lastly, fTCD has been used as a brain–computer interface modality.
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Native records of contractile activity of the left ventricle of isolated rat heart perfused under Langendorff technique. Curve A - contractile function of the heart is greatly depressed after ischemia-reperfusion. Curve B - a set of short ischemic episodes (ischemic preconditioning) before prolonged ischemia provides functional recovery of contractile activity of the heart at reperfusion. The Langendorff heart or isolated perfused heart assay is an ex vivo technique used in pharmacological and physiological research using animals and also humans.
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The radiopharmaceutical then goes into the bile ducts, the gallbladder, and the intestines. The gamma camera is placed on the abdomen to picture these perfused organs. Other scintigraphic tests are done similarly.
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While a single subject/animal is perfused with multiple concentrations during the no-net-flux method, multiple subjects are perfused with a single concentration during the dynamic no-net-flux (DNNF) method. Data from the different subjects/animals is then combined at each time point for regression analysis allowing determination of the recovery over time. The design of the DNNF calibration method has proven very useful for studies that evaluate the response of endogenous compounds, such as neurotransmitters, to drug challenge.
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Reconstruction of outflow tracts via spectral domain optical coherence tomography have confirmed a correlation between aqueous spaces and collectors where flow was seen. However, these studies have also confirmed the existence of non-perfused vascular structures that could be part of the arterial or venous vascular system, or poorly perfused collector channels. Recent discoveries have shown valve-like structures that appear to guard collector channel orifices and collapsible aqueous veins 9, 10. These findings contradict the view that collector channel openings are round and unobstructed.
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Cyon studied medicine at the medical-surgical academy in Warsaw, at the University of Kiev and in Berlin. He obtained a degree in medicine in Kiev in 1864. In 1866 he worked in Leipzig as an assistant to Carl Ludwig (1816–1895), with whom he collaborated on creation of the first isolated perfused frog heart preparation.Physiology Online The Isolated Perfused Heart and Its Pioneers From 1867 he taught classes on anatomy and physiology at the University of St. Petersburg, where he was assistant to the director of the physiology laboratory, Filipp Ovsyannikov.
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Peripheral edema is edema (accumulation of fluid causing swelling) in tissues perfused by the peripheral vascular system, usually in the lower limbs. In the most dependent parts of the body (those hanging distally), it may be called dependent edema.
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Dead space is the volume of air that is inhaled that does not take part in the gas exchange, because it either remains in the conducting airways or reaches alveoli that are not perfused or poorly perfused. In other words, not all the air in each breath is available for the exchange of oxygen and carbon dioxide. Mammals breathe in and out of their lungs, wasting that part of the inhalation which remains in the conducting airways where no gas exchange can occur. Benefits do accrue to a seemingly wasteful design for ventilation that includes dead space.
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Nirmala G, Brahmayya Sastry P. Neuro-muscular depressant action of pindolol in comparison with propranolol and procaine. Arch Int Pharmacodyn Ther. 1979 Apr;238(2):196-205. 5\. Raghavan KS, Sastry PB. Effects of temperature on acetylcholine synthesis and release in perfused human placenta.
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Recent studies have used hypoxic-staining dyes, such as Hoechst stain, to show that quiescent LT-HSCs and osteoblasts are found in hypoxic and poorly perfused areas of the bone marrow, while ECs and MSCs were found in well-perfused areas. However, this hypoxia may be only caused in part by the niche environment, and the HSCs themselves may be maintaining their hypoxic environment in order to remain quiescent. This oxygen tension upregulates HIF1A, which shifts energy production to glycolysis, allowing for the cell to survive in oxygen-poor surroundings. Indeed, deletion of HIF1A increases HSC proliferation and eventually depletes the LT-HSC storage pool.
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At the end of treatment, contrast enhanced MR imaging is used to assess the effectiveness of the procedure. These images are used to determine the Non-Perfused Volume (NPV) of the fibroid, which is the volume of tissue that is non-viable (has no blood flow to it).
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Medscape > Testicular Torsion Imaging by David Paushter. Updated: May 25, 2011 Initially it provides a radionuclide angiogram, followed by a static image after the radionuclide has perfused the tissue. In the healthy patient, initial images show symmetric flow to the testes, and delayed images show uniformly symmetric activity.
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Clements et al. reported that rottlerin improves the recovery of isolated rat hearts perfused with buffer after cold cardioplegic arrest. A majority of patients recover but some develop a cardiac low-output syndrome attributable in part to depressed left ventricular or atrial contractility, which increases chance of death.
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White softening is another form of cerebral softening. This type of softening occurs in areas that continue to be poorly perfused, with little to no blood flow. These are known as "pale" or "anemic infarcts" and are areas that contain dead neuronal tissue, which result in a softening of the cerebrum.
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Reddi YV, Sastry PB, Ramadas G. The effects of excess calcium on the acetylcholine turnover from the minced and incubated rat's brain. Indian J Physiol Pharmacol. 1978 Jul-Sep;22(3):285-92. 9\. Sastry PB, Krishnamurty A. Acetylcholine synthesis and release in isolated and perfused single cotyledon of human placenta.
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Faulk DM, et al. "Role of the extracellular matrix in whole organ engineering" These scaffolds can then be re-cellularized in an attempt to regenerate whole organs for transplant. This method works primarily for organs with a complex vasculature, as it allows detergent to be fully perfused through the material.
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A new testing platforms based on multi- compartmental perfused systems have gained a remarkable interest in pharmacology and toxicology. It aims to provide a cell culture environment close to the in vivo situation to reproduce more reliably in vivo mechanisms or ADME processes that involve its absorption, distribution, metabolism, and elimination. Perfused in vitro systems combined with kinetic modelling are promising tools for studying in vitro the different processes involved in the toxicokinetics of xenobiotics. Efforts made toward the development of micro fabricated cell culture systems that aim to create models that replicate aspects of the human body as closely as possible and give examples that demonstrate their potential use in drug development, such as identifying synergistic drug interactions as well as simulating multi-organ metabolic interactions.
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ANNINE-6plus has been applied in the microscopic imaging of action potentials of cardiomyocyte in perfused mice heart. Using confocal microscopy in conjunction with ANNINE-6plus, single sweep action potentials with high peak signal-to-noise ratio (SNR) have been recorded from single transverse tubule (t-tubule) of a few micrometers in the ventricular cardiomyocyte.
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The term «vascular recruitment» or «capillary recruitment» usually refers to the increase in the number perfused capillaries in skeletal muscle in response to a stimulus. The most important stimulus in humans is regular exercise.Vascular recruitment in forearm muscles during exercise. Palm T, Nielsen SL, Lassen NA. Clin Physiol. 1983 Oct;3(5):445-51.
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Entero-oxyntin is a hormone released from intestinal endocrine cells which stimulates gastric acid secretion in the stomach. It has been isolated from animalsWalker WA, Strodel WE, Eckhauser FE, Heldsinger A, Vinik AI. J Surg Res. 1983 May;34(5):486-92., Enterooxyntin release from isolated perfused canine jejunum.. and is hypothesised to exist in humans.
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Hannan's research activities include: # Effect of plant fractions on insulin secretion in perfused rat pancreas and isolated islets. # Effect of antidiabetic plant materials on carbohydrate digestion and absorption in the gut of rats. # Studies on fish oils for the management of insulin resistance, dyslipidemia and platelet aggregation associated with type 2 diabetes. # Biochemical feature of Bangladeshi Young Diabetic subjects.
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A placental disease is any disease, disorder, or pathology of the placenta. Ischemic placental disease leads to the attachment of the placenta to the uterine wall to become under-perfused, causing uteroplacental ischemia. Where the term overarches the pathology associated with preeclampsia, placental abruptions and intrauterine growth restriction (IUGR). These factors are known to be the primary pathophysiology cause placental disease.
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The proximal two-thirds of the transverse colon is perfused by the middle colic artery, a branch of the superior mesenteric artery (SMA), while the latter third is supplied by branches of the inferior mesenteric artery (IMA). The "watershed" area between these two blood supplies, which represents the embryologic division between the midgut and hindgut, is an area sensitive to ischemia.
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Widmaier, Eric P., Hershel Raff, Kevin T. Strang, and Arthur J. Vander (2008) Vander's Human Physiology: the Mechanisms of Body Function.' Boston: McGraw-Hill Higher Education. As the brain requires nutrient entry and waste removal, it is perfused by blood flow. Blood can carry a number of ingested toxins, however, which would induce significant neuron death if they reach nervous tissue.
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According to SynapseWeb, this is the recipe for Golgi's staining technique: #Immerse a block (approx. 10x5 mm) of formaldehyde-fixed (or paraformaldehyde- glutaraldehyde-perfused) brain tissue into a 2% aqueous solution of potassium dichromate for 2 days #Dry the block shortly with filter paper. #Immerse the block into a 2% aqueous solution of silver nitrate for another 2 days. #Cut sections approx.
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It is distributed in small quantities through less perfused tissues like muscle, fat and peripheral organs. The drug can be moved from the plasma to the tissue until the equilibrium is established (for unbound drug present in plasma). The concept of compartmentalization of an organism must be considered when discussing a drug’s distribution. This concept is used in pharmacokinetic modelling.
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Ischemic ATN can be caused when the kidneys are not sufficiently perfused for a long period of time (i.e. renal artery stenosis) or during shock. Hypoperfusion can also be caused by embolism of the renal arteries. Given their importance in massive nutrient and electrolyte reabsorption, the proximal tubule and medullary thick ascending limb require significant ATP and are most susceptible to ischemic damage.
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Alveolar dead space is sum of the volumes of those alveoli which have little or no blood flowing through their adjacent pulmonary capillaries, i.e., alveoli that are ventilated but not perfused, and where, as a result, no gas exchange can occur. Alveolar dead space is negligible in healthy individuals, but can increase dramatically in some lung diseases due to ventilation-perfusion mismatch.
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Upon autopsy of several subjects, Dr. Cornelio Fazio found that the most common areas of this type of softening occurred where there was a hemorrhage of the middle cerebral artery or the superior or deep branches to it. The subjects' softened area was not always near the arteries but where the capillaries perfused the brain tissue. The symptoms were similar to that of a stroke.Fazio, Cornelio.
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Hyperthermic intrathoracic chemotherapy is used in conjunction with surgery, Online manual: Management of Peritoneal Surface Malignancy . including in patients with malignant pleural mesothelioma. The surgeon removes as much of the tumor as possible followed by the direct administration of a chemotherapy agent, heated to between 40 and 48 °C, in the abdomen. The fluid is perfused for 60 to 120 minutes and then drained.
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Interconnected 3 compartment models, as used in the Goldman models In contrast to the independent parallel compartments of the Haldanean models, in which all compartments are considered risk bearing, the Goldman model posits a relatively well perfused "active" or "risk-bearing" compartment in series with adjacent relatively poorly perfused "reservoir" or "buffer" compartments, which are not considered potential sites for bubble formation, but affect the probability of bubble formation in the active compartment by diffusive inert gas exchange with the active compartment. During compression, gas diffuses into the active compartment and through it into the buffer compartments, increasing the total amount of dissolved gas passing through the active compartment. During decompression, this buffered gas must pass through the active compartment again before it can be eliminated. If the gas loading of the buffer compartments is small, the added gas diffusion through the active compartment is slow.
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Lindbergh began to wonder why hearts could not be repaired with surgery. Starting in early 1931 at the Rockefeller Institute and continuing during his time living in France, Lindbergh studied the perfusion of organs outside the body with Nobel Prize-winning French surgeon Alexis Carrel. Although perfused organs were said to have survived surprisingly well, all showed progressive degenerative changes within a few days."The Development of Cardiopulmonary Bypass". ctsnet.org.
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To migrate, endothelial cells need collagenases and plasminogen activator to degrade the clot and part of the ECM. Zinc-dependent metalloproteinases digest basement membrane and ECM to allow cell migration, proliferation and angiogenesis. When macrophages and other growth factor-producing cells are no longer in a hypoxic, lactic acid-filled environment, they stop producing angiogenic factors. Thus, when tissue is adequately perfused, migration and proliferation of endothelial cells is reduced.
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Echocardiography: In babies under the age of 12 months, echocardiography is considered to be sensitive and specific in making the diagnosis of double aortic arch when both arches are open. Non-perfused elements of other types of vascular rings (e.g. left arch with atretic (closed) end) or the ligamentum arteriosum might be difficult to visualize by echocardiography. Computed tomography (CT): Computed tomography after application of contrast media is usually diagnostically accurate.
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It was submitted on 3 May 1928 and published as volume 268 of Virchows Archiv. Following the completion of her studies she moved to Berlin to work as a house physician. A year later, she was persuaded by Paul Trendelenburg to work at his laboratory in Berlin. While in his laboratory she was required to demonstrate the perfused frog heart in which inflow and outflow resistance could be controlled.
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If tissue is not being perfused properly, it may feel cold and appear pale; if severe, hypoxia can result in cyanosis, a blue discoloration of the skin. If hypoxia is very severe, a tissue may eventually become gangrenous. Extreme pain may also be felt at or around the site. Tissue hypoxia from low oxygen delivery may be due to low haemoglobin concentration (anaemic hypoxia), low cardiac output (stagnant hypoxia) or low haemoglobin saturation (hypoxic hypoxia).
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Because of this requirement, vascularized tissues can have chemicals and enzymes perfused through the present arteries, veins, and capillaries. Under this mechanism and proper physiological conditions, treatments can diffuse equally to all of the cells within the organ. The treatments can be removed through the veins at the end of the process. Cardiac and pulmonary decellularization often uses this process of decellularization to introduce the treatments because of their heavily vascularized networks.
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Farmacocinética III:Distribución Available on (in Spanish). Visited 10 January 2009 The distribution of a drug between tissues is dependent on vascular permeability, regional blood flow, cardiac output and perfusion rate of the tissue and the ability of the drug to bind tissue and plasma proteins and its lipid solubility. pH partition plays a major role as well. The drug is easily distributed in highly perfused organs such as the liver, heart and kidney.
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In children, however, postoperative immunity may be abnormal and vaccinations for several infectious agents are recommended. Invasive thymomas may require additional treatment with radiotherapy and chemotherapy (cyclophosphamide, doxorubicin and cisplatin).. Recurrences of thymoma are described in 10-30% of cases up to 10 years after surgical resection, and in the majority of cases also pleural recurrences can be removed. Recently, surgical removal of pleural recurrences can be followed by hyperthermic intrathoracic perfusion chemotherapy or intrathoracic hyperthermic perfused chemotherapy (ITH).
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Consider some scenarios where there is a defect in ventilation and/ or perfusion of the lungs. In condition such as pulmonary embolism, the pulmonary blood flow is affected, thus the ventilation of the lung is adequate, however there is a perfusion defect with defect in blood flow. Gas exchange thus becomes highly inefficient leading to hypoxemia as measured by arterial oxygenation. A ventilation perfusion scan or lung scintigraphy shows some areas of lungs being ventilated but not adequately perfused.
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He later released a few Ep's on his own imprint Vibrant Music. He went silent for a few years but resurfaced with a somewhat bolder approach on 2009-2010 releases through Resopal (Constant Limber) and Echocord (Perfused). His collaboration with Echocord continued with the Traces and Broadwalk Tales albums, while Type reissued the first Vibrant Forms collection. Fluxion collaborated with Subwax BCN in 2016; the label reissued Vibrant Forms II and released the newly recorded Vibrant Forms III.
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However, Gauthier disagrees and suggests that the category- specific and process-map models could accommodate most other proposed models for the neural underpinnings of facial processing. Most neuroanatomical substrates for facial processing are perfused by the middle cerebral artery (MCA). Therefore, facial processing has been studied using measurements of mean cerebral blood flow velocity in the middle cerebral arteries bilaterally. During facial recognition tasks, greater changes in the right middle cerebral artery (RMCA) than the left (LMCA) have been observed.
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A major challenge facing the intestinal transplant enterprise is meeting the need for transplantable intestines, particularly in the United States where the majority of intestinal transplants take place. There exists a narrow timeslot between procurement and transplantation that any organ remains viable, and logistical challenges are faced regarding bringing organ and recipient together. During procurement, organs that are being recovered are cooled and perfused with preservation solution. This slows organ activity and increases the time they remain viable for transplant.
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Phenoxybenzamine, a vasodilator and lysozomal enzyme stabiliser, was injected into the renal artery before nephrectomy. The kidneys were immersed in saline immediately after removal, and perfused through the renal artery with 100-150 ml of a cold electrolyte solution from a height of 100 cm. The kidneys remained in iced saline for the rest of the storage period. The solution used for these successful cold perfusions imitated the electrolyte composition of intracellular fluids by containing large amounts of potassium and magnesium.
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Therefore, vascular remodelling does not depend on the presence of oxygen and in fact occurs before perfused tissues require oxygen delivery. However, it is still unknown whether or not other nutrients or genetic factors may have promotional effects on vascular remodelling. Measurement of parabolic velocity profiles in live embryo vessels indicate that vessel walls are exposed to levels of laminar and shear stress which can have a bioactive effect. Shear stress on embryonic mouse and chicken vasculature ranges between 1 – 5 dyn/cm2.
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The calcium blocking activity of AH-1058 can decrease ventricular contractility, heart rate, and conductance through the atrioventricular node.Takahara A, Sugiyama A, Dohmoto H, et al. Comparison of cardiovascular effects of a new calcium channel blocker AH-1058 with those of verapamil assessed in blood-perfused canine heart preparations. Journal of Cardiovascular Pharmacology 2000; vol 35:741-748 In addition AH-1058 has been shown to decrease systolic blood pressure while minimally affecting total peripheral vascular resistance and leaving diastolic blood pressure unaffected.
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Oskar Langendorff (1 February 1853 in Breslau - 10 May 1908 in Rostock; his first name is sometimes given as "Oscar") was a German physician and physiologist known primarily for his experiments on the isolated perfused heart, the so-called Langendorff Heart apparatus. In addition, he is credited with discoveries in respiration and in the conduction of impulses in the sympathetic and peripheral nervous system. His work has served as the basis for the use of retrograde perfusion in science and medicine.
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That is, patients requiring an advanced airway may have had a poorer prognosis in relation to those requiring basic interventions to begin with. For the management of in-hospital cardiac arrest however, studies currently support the establishment of an advanced airway. It is well documented that quality chest compressions with minimal interruption result in improved survival. This is suggested to be due, in part, to decreased no-flow-time in which vital organs, including the heart are not adequately perfused.
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Complications arising from intrauterine hypoxia are some of the leading causes of preeclampsia. Preeclampsia is a hypertensive disorder that occurs during the second trimester (after the 20th week of pregnancy) resulting from a poorly perfused placenta. Studies from the World Health Organization show that globally, about 14% (50,000- 750000 women) of maternal deaths annually are caused by preeclampsia and eclampsia. During pregnancy, women with preeclampsia faces serious risk of damage to vital organs such as the kidneys, liver, brain, and the blood system.
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In emperor penguins perfusion may be variable at the start of a dive, and muscle may or may not be perfused. Arterial-venous shunts may be opened to allow venous blood oxygen storage. Extremely low heart rates at the deepest part of the dive should limit nitrogen absorption, conserve blood oxygen, and increase aerobic muscle metabolism based on myoglobin-bound oxygen reserves. Aquatic birds have to overcome the drag created between their bodies and the surrounding water while swimming at the surface or underwater.
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Russell and Burch also considered levels of replacement. In "relative replacement", animals are still required, though during an experiment they are exposed, probably or certainly, to no distress at all. In "absolute replacement", animals are not required at all at any stage. Replacement strategies include: #Tissue culture #Perfused organs #Tissue slices #Cellular fractions #Subcellular fractions More recent interpretations of the replacement principle suggest the preferred use of non- animal methods over animal methods whenever it is possible to achieve the same scientific aims, i.e.
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Coagulative necrosis is most commonly caused by conditions that do not involve severe trauma, toxins or an acute or chronic immune response. The lack of oxygen (hypoxia) causes cell death in a localised area which is perfused by blood vessels failing to deliver primarily oxygen, but also other important nutrients. It is important to note that while ischemia in most tissues of the body will cause coagulative necrosis, in the central nervous system ischemia causes liquefactive necrosis, as there is very little structural framework in neural tissue.
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A deletion of the C-terminal 19 amino acids was found during myocardial ischemia-reperfusion injury in Langendorff perfused rat hearts. It was also seen in myocardial stunning in coronary bypass patients. Over-expression of the C-terminal truncated cardiac TnI (cTnI1-192) in transgenic mouse heart resulted in a phenotype of myocardial stunning with systolic and diastolic dysfunctions. Replacement of intact cTnI with cTnT1-192 in myofibrils and cardiomyocytes did not affect maximal tension development but decreased the rates of force redevelopment and relaxation.
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Highly lipid- soluble drugs given by intravenous or inhalation methods are initially distributed to organs with high blood flow. Later, less vascular but more bulky tissues (such as muscle and fat) take up the drug—plasma concentration falls and the drug is withdrawn from these sites. If the site of action of the drug was in one of the highly perfused organs, redistribution results in termination of the drug action. The greater the lipid solubility of the drug, the faster its redistribution will be.
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The mausoleum of Timurid princes, with their turquoise and blue-tiled domes remain among the most refined and exquisite Persian architecture.Hugh Kennedy, The Great Arab Conquests: How the Spread of Islam Changed the World We Live In, Da Capo Press, 2007. p. 237 Axial symmetry is a characteristic of all major Timurid structures, notably the Shāh-e Zenda in Samarkand, the Musallah complex in Herat, and the mosque of Gawhar Shad in Mashhad. Double domes of various shapes abound, and the outsides are perfused with brilliant colors.
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If the kidney is methodologically perfused at moderate pressures (90–220 mm Hg performed on an experimental animal; in this case, a dog), then, there is a proportionate increase of: -Renal Vascular Resistance Along with the increase in pressure. At low perfusion pressures, Angiotensin II may act by constricting the efferent arterioles, thus mainlining the GFR and playing a role in autoregulation of Renal Blood Flow. People with poor blood flow to the kidneys caused by medications that inhibit angiotensin-converting enzyme may face kidney failure.
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Ventilation-perfusion scintigraphy (A) After inhalation of 20 mCi of Xenon-133 gas, scintigraphic images were obtained in the posterior projection, showing uniform ventilation to lungs. (B) After intravenous injection of 4 mCi of Technetium-99m-labeled albumin, scintigraphic images shown here in the posterior projection. This and other views showed decreased activity in multiple regions. A ventilation/perfusion scan (or V/Q scan or lung scintigraphy) shows that some areas of the lung are being ventilated but not perfused with blood (due to obstruction by a clot).
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After this waiting period, the organ procurement surgery beings as quickly as possible to minimize time that the organs are not being perfused with blood. DCD had been the norm for organ donors until 'brain death' became a legal definition in the United States in 1981. Since then, most donors have been brain-dead. If consent is obtained from the potential donor or the potential donor's survivors, the next step is to perform a match between the source (donor) and the target (recipient) to reduce rejection of the organ by the recipient's immune system.
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This potential danger of using cryoprecipitated plasma was demonstrated experimentally by Filo who perfused dog kidneys for 24 hours with specifically sensitised cryoprecipitated dog plasma and found that he could induce glomerular and vascular lesions with capillary engorgement, endothelial swelling, infiltration by polymorphonuclear leucocytes and arterial thrombosis. Immunofluorescent microscopy demonstrated specific binding of IgG along endothelial surfaces, in glomeruli, and also in vessels. After reimplantation, complement fixation and tissue damage occurred in a similar pattern. There was some correlation between the severity of the histological damage and subsequent function of the kidneys.
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Slice work under a microscope also allows for careful placement of the recording electrode, which would not be possible in the closed in vivo system. Removing the brain tissue means that there is no blood–brain barrier, which allows drugs, neurotransmitters or their modulators, or ions to be perfused throughout the neural tissue. Finally, whilst the circuit isolated in a brain slice represents a simplified model of the circuit in situ, it maintains structural connections that are lost in cell cultures, or homogenised tissue. However, slice preparation also has some drawbacks.
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Premature Ventricular Contraction (PVC) can be seen in the PPG just as in the EKG and the Blood Pressure (BP). Venous pulsations can be clearly seen in this PPG. Because the skin is so richly perfused, it is relatively easy to detect the pulsatile component of the cardiac cycle. The DC component of the signal is attributable to the bulk absorption of the skin tissue, while the AC component is directly attributable to variation in blood volume in the skin caused by the pressure pulse of the cardiac cycle.
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Retrograde perfusion (retroperfusion) is an artificial method of providing blood supply to an organ by delivering oxygenated blood through the veins. It may be performed during surgery that interrupts the normal arterial supply of blood to that organ. For instance, when performing surgery that interrupts the cerebral arteries, a hose placed into the femoral artery and the superior vena cava can redirect blood up the internal jugular vein to supply the brain. This technique was pioneered by Oscar Langendorff, who perfused mamallian hearts ex vivo for research applications.
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In the Langendorff preparation, the heart is removed from the animal's or human's body, severing the blood vessels; it is then perfused in a reverse fashion (retrograde perfusion) via the aorta, usually with a nutrient rich, oxygenated solution (e.g. Krebs–Henseleit solution or Tyrode's solution). The backwards pressure causes the aortic valve to shut, forcing the solution into the coronary vessels, which normally supply the heart tissue with blood. This feeds nutrients and oxygen to the cardiac muscle, allowing it to continue beating for several hours after its removal from the animal or human.
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The low-flow-rate method is based on the fact that the extraction efficiency is dependent on the flow-rate. At high flow-rates, the amount of drug diffusing from the sampling site into the dialysate per unit time is smaller (low extraction efficiency) than at lower flow-rates (high extraction efficiency). At a flow-rate of zero, a total equilibrium between these two sites is established (Cout = Csample). This concept is applied for the (low-)flow-rate method, where the probe is perfused with blank perfusate at different flow-rates.
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Catecholamines will also cause peripheral vasoconstriction, which causes increased systemic vascular resistance and ensures that organs are adequately perfused. Renin, a proteolytic enzyme, cleaves angiotensinogen to angiotensin I, which is converted to angiotensin II. In the case of chronic aortic insufficiency with resultant cardiac remodeling, heart failure will develop, and it is possible to see systolic pressures diminish. Aortic insufficiency causes both volume overload (elevated preload) and pressure overload (elevated afterload) of the heart. The volume overload, due to elevated pulse pressure and the systemic effects of neuroendocrine hormones causes left ventricular hypertrophy (LVH).
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Warnick and Bergstrom also showed that cooling the kidney immediately after removal markedly reduced any further ATP loss. When these non warm-injured kidneys were perfused with oxygenated hypothermic plasma, ATP levels were reduced by 50% after 24-hour storage and, after 48 hours, mean tissue ATP levels were a little higher than this indicating that synthesis of ATP had occurred. Pegg has shown that rabbit kidneys can resynthesize ATP after a period of perfusion storage following warm injury, but no resynthesis occurred in non warm-injured kidneys. Warm anoxia can also occur during reimplantation of the kidney after storage.
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Pettersson showed that, on a molar basis, glucose and fatty acids were metabolised by hypothermically perfused kidneys at about the same rates. The cortex of the hypothermic dog kidney was shown by Huang to lose lipid (35% loss of total lipid after 24 hours) unless oleate was added to the kidney perfusate. Huang commented that this loss could affect the structure of the cell and that the loss also suggested that the kidney was utilising fatty acid. In a later publication Huang showed that dog kidney cortex slices metabolised fatty acids, but not glucose, at 10 °C.
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Perfusion storage methods can mechanically injury the vascular endothelium of the kidney, which leads to arterial thrombosis or fibrin deposition after reimplantation. Hill noted that, in human kidneys, fibrin deposition in the glomerulus after reimplantation and postoperative function, correlated with the length of perfusion storage. He had taken biopsies at revascularisation from human kidneys preserved by perfusion or ice storage, and showed by electron microscopy that endothelial disruption only occurred in those kidneys that had been perfused. Biopsies taken one hour after revascularisation showed platelets and fibrin adherent to any areas of denuded vascular basement membrane.
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The areas containing well-perfused structures with high hemoglobin concentration are visualized in white or light green, and the areas with no vascularization are seen as dull green or black. Mathematical algorithms reconstruct 3-dimensional translucent images that can be rotated along any axis in real time. In 3D space, the images are analyzed in two different projections, maximum intensity projection (MIP) and front to back projection (FTB), also known as a Surface Rendering Mode. These two modes combined are used to evaluate the vascularization patterns and to distinguish a normal vessel from an abnormal vascularization.
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The cryonics procedure performed by the Cryonics Institute begins with a process called vitrification where the body is perfused with cryoprotective agents to protect against damage in the freezing process. After this, the body is cooled to -196 °C over the course of a day or two days in a computer-controlled chamber before being placed in a long-term storage container filled with liquid nitrogen. The Cryonics Institute calls their storage units cryostats, and each unit contains up to six people. The process can take place only once the person has been declared legally dead.
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The permeability properties of the stratum corneum are, for the most part, unchanged after its removal from the body. Skin that has been removed carefully from animals may also be used to see the extent of local penetration by putting it in a chamber and applying the chemical on one side and then measuring the amount of chemical that gets into a fluid on the other side. One example of this ex vivo technique is the isolated perfused porcine flap. This method was first described in 1986 as a humane alternative to in vivo animal testing.
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It has been shown that both electrical contraction and AICA ribonucleotide (AICAR) treatment increase AMPK activation, glucose uptake, and GLUT-4 translocation in perfused rat hindlimb muscle, linking exercise-induced glucose uptake to AMPK. Chronic AICAR injections, simulating some of the effects of endurance training, also increase the total amount of GLUT-4 protein in the muscle cell. Two proteins are essential for the regulation of GLUT-4 expression at a transcriptional level – myocyte enhancer factor 2 (MEF2) and GLUT4 enhancer factor (GEF). Mutations in the DNA binding regions for either of these proteins results in ablation of transgene GLUT-4 expression.
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Like almost all of Andrić's works, the book was originally written in Serbian Cyrillic. The characters use the Ijekavian dialect of Serbo-Croatian primarily spoken west of the Drina, while the narrator uses the Ekavian dialect spoken primarily in Serbia. This is a reflection of Andrić's own linguistic proclivities, as he had abandoned both written and spoken Ijekavian and reverted to Ekavian upon moving to Belgrade in the early 1920s. Both dialogue and narration passages are perfused with Turkisms (), words of Turkish, Arabic or Persian origin that had found their way into the South Slavic languages under Ottoman rule.
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Due to the local deposition, SIRT is regarded as a type of locoregional therapy (LRT). The liver has a dual blood supply system; it receives blood from both the hepatic artery and the portal vein. The healthy liver tissue is mainly perfused by the portal vein, while most liver malignancies derive their blood supply from the hepatic artery. Therefore, locoregional therapies such as transarterial chemoembolization or radioembolization, can selectively be administered in the arteries that are supplying the tumors and will preferentially lead to deposition of the particles in the tumor, while sparing the healthy liver tissue from harmful side effects.
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Excretion is primarily hepatic and biliary with almost no elimination via the renal route and it is not dialyzable [Package Insert- Pacerone(R)]. Elimination half-life average of 58 days (ranging from 25–100 days [Remington: The Science and Practice of Pharmacy 21st edition]) for amiodarone and 36 days for the active metabolite, desethylamiodarone (DEA) [Package Insert- Pacerone(R)]. There is 10-50% transfer of amiodarone and DEA in the placenta as well as a presence in breast milk [Package Insert- Pacerone(R)]. Accumulation of amiodarone and DEA occurs in adipose tissue and highly perfused organs (i.e.
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During calibration with the no-net-flux-method, the microdialysis probe is perfused with at least four different concentrations of the analyte of interest (Cin) and steady-state concentrations of the analyte leaving the probe are measured in the dialysate (Cout). The recovery for this method can be determined by plotting Cout−Cin over Cin and computing the slope of the regression line. If analyte concentrations in the perfusate are equal to concentrations at the sampling site, no-net flux occurs. Respective concentrations at the no-net-flux point are represented by the x-intercept of the regression line.
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Often, even a complete occlusion is totally asymptomatic because bilateral circulation keeps the brain well perfused. However, when blood clots form and break off from the site of the tear, they form emboli, which can travel through the arteries to the brain and block the blood supply to the brain, resulting in an ischaemic stroke, otherwise known as a cerebral infarction. Blood clots, or emboli, originating from the dissection are thought to be the cause of infarction in the majority of cases of stroke in the presence of carotid artery dissection. Cerebral infarction causes irreversible damage to the brain.
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A brainstem stroke syndrome falls under the broader category of stroke syndromes, or specific symptoms caused by vascular injury to an area of brain (for example, the lacunar syndromes). As the brainstem contains numerous cranial nuclei and white matter tracts, a stroke in this area can have a number of unique symptoms depending on the particular blood vessel that was injured and the group of cranial nerves and tracts that are no longer perfused. Symptoms of a brainstem stroke frequently include sudden vertigo and ataxia, with or without weakness. Brainstem stroke can also cause diplopia, slurred speech and decreased level of consciousness.
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The concentration of carbon dioxide (CO2) in healthy alveoli is known. It is equal to its concentration in arterial blood since CO2 rapidly equilibrates across the alveolar–capillary membrane. The quantity of CO2 exhaled from the healthy alveoli will be diluted by the air in the conducting airways and by air from alveoli that are poorly perfused. This dilution factor can be calculated once the CO2 in the exhaled breath is determined (either by electronically monitoring the exhaled breath or by collecting the exhaled breath in a gas impermeant bag (a Douglas bag) and then measuring the mixed gas in the collection bag).
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The TRAM free-flap is harvested from the musclus transversus abdominis of the trunk. (right) ;Technique The Transverse Rectus Abdominis Myocutaneous free- flap, created from the transverse abdominal muscle, is a breast reconstruction flap harvested from the abdomen of the woman. The TRAM flap is composed of skin, adipocyte fat, and the musculus rectus abdominis, which is perfused (irrigated) by the deep inferior epigastric artery and by the deep inferior epigastric vein. Once the TRAM free flap is transposed to the woman's chest, the epigastric blood vessels are anastomosed (connected) to the internal thoracic vein to maintain the tissue viability of the reconstructed breast.
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If every alveolus was perfectly ventilated and all blood from the right ventricle were to pass through fully functional pulmonary capillaries, and there was unimpeded diffusion across the alveolar and capillary membrane, there would be a theoretical maximum blood gas exchange, and the alveolar PO2 and arterial PO2 would be the same. The formula for shunt describes deviation from this ideal. A normal lung is imperfectly ventilated and perfused, and a small degree of intrapulmonary shunting is normal. Anatomical shunting occurs when blood supply to the lungs via the pulmonary arteries is returned via the pulmonary veins without passing through the pulmonary capillaries, thereby bypassing alveolar gas exchange.
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The goal of surgical cytoreduction is to remove all gross disease including tumors that are in resectable areas of the lung or other structures and any large pleural nodules. After complete resection of visible disease, the chest cavity is perfused with hyperthermic chemotherapy with the goal of treating microscopic or minimally visible disease. The chemotherapy bathes the inside of the chest in concentrations that are very effective against the cancer cells but without the level of toxicity that could occur if the chemotherapy was given through the blood stream. The increased heat of the chemotherapy perfusion can itself injure the cancer cells and makes the chemotherapy more effective.
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Chemotherapy (typically utilising the chemotherapeutic agent Mitomycin C) may be infused directly into the abdominal cavity after cytoreductive surgery (curgery removing all visible disease to kill remaining microscopic cancerous tumors and free floating cells. The heated chemotherapy (HIPEC) is perfused throughout the abdominal cavity for an hour or two as the last step in the surgery, or ports are installed to allow circulation and/or drainage of the chemicals for one to five days after surgery, known as early postoperative intraperitoneal chemotherapy (EPIC). EPIC may be given in multiple cycles for several months after surgery. Systemic chemotherapy may be administered as additional or adjuvant treatment.
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The microdialysis technique requires the insertion of a small microdialysis catheter (also referred to as microdialysis probe) into the tissue of interest. The microdialysis probe is designed to mimic a blood capillary and consists of a shaft with a semipermeable hollow fiber membrane at its tip, which is connected to inlet and outlet tubing. The probe is continuously perfused with an aqueous solution (perfusate) that closely resembles the (ionic) composition of the surrounding tissue fluid at a low flow rate of approximately 0.1-5μL/min. Once inserted into the tissue or (body)fluid of interest, small solutes can cross the semipermeable membrane by passive diffusion.
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Atrial fibrillation represents a common electrical malady in the heart that appears during the time interval of atrial systole (see figure at right margin). Theory suggests that an ectopic focus, usually situated within the pulmonary trunks, competes with the sinoatrial node for electrical control of the atrial chambers and thereby diminishes the performance of the atrial myocardium, or atrial heart muscle. The ordered, sinoatrial control of atrial electrical activity is disrupted, causing the loss of coordinated generation of pressure in the two atrial chambers. Atrial fibrillation represents an electrically-disordered but well perfused atrial mass working (in an uncoordinated fashion) with a (comparatively) electrically-healthy ventricular systole.
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Int J Obes 29:682–688 Hot peppers have been reported to induce thermogenesis at the cellular level.Yoshioka, M., Lim, K., Kikuzato, S., Kiyonaga, A., Tanaka H. and Shindo M. (1995) Effects of red-pepper diet on the energy metabolism in men, J Nutr Sci Vitaminol. 41:647–656Eldershaw T.P., Colquhoun E.Q., Bennett K.L., Dora K.A. and Clark M.G. (1994) Resiniferatoxin and piperine: capsaicin- like stimulators of oxygen uptake in the perfused rat hindlimb, Life Sci 55:389–397 As well, capsaicin induces satiety as a result of oral and gastro- intestinal contribution. Lower energy and fat intake were observed under short-term conditions; however, the effect of the spice was reduced over prolonged exposure.
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Plaa's primary area of research was hepatotoxicity, in which his successes where achieved primarily by the investigation of mechanistic toxicology. His primary contributions were in the areas of cholestasis and toxic potentiation, in particular potentiation by haloalkanes. Although the use of the isolated perfused liver was already well-known, having been first used in the early 19th century, Plaa was the first to use it for the study of hepatotoxicity. A long-time career goal for him was to elaborate methods to determine human hepatotoxicity (and particularly cholestasis-inducing abilities in drugs) from animal tests; although this endeavour was never a success, it led to a much improved understanding of the mechanisms of cholestasis.
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For several years thereafter, Cryovita Laboratories led by Jerry Leaf and Mike Darwin, were responsible for the initial cryonic suspension of patients of the American Cryonics Society, which were then perfused, transported, and kept in cryogenic storage by Trans Time. This method of making use of contract companies as a means of risk management was unique to the American Cryonics Society and has been followed to the present day. In 1992, the American Cryonics Society signed contracts with the newly formed CryoSpan Corporation and transferred a number of patients to that Southern California facility, as well as making use of CryoSpan services for a number of new patients. At about this same time it contracted with BioPreservation Inc.
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Peirce called (with no sense of deprecation) "mathematics of logic" much of the kind of thing which, in current research and applications, is called simply "logic". He was productive in both (philosophical) logic and logic's mathematics, which were connected deeply in his work and thought. Peirce argued that logic is formal semiotic, the formal study of signs in the broadest sense, not only signs that are artificial, linguistic, or symbolic, but also signs that are semblances or are indexical such as reactions. Peirce held that "all this universe is perfused with signs, if it is not composed exclusively of signs",Peirce, Collected Papers of Charles Sanders Peirce, 5.448 footnote, from "The Basis of Pragmaticism" in 1906.
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118–123 Experiments have been performed to test precisely how the glycocalyx can be altered or damaged. One particular study used an isolated perfused heart model designed to facilitate detection of the state of the vascular barrier portion, and sought to cause insult-induced shedding of the glycocalyx to ascertain the cause-and-effect relationship between glycocalyx shedding and vascular permeability. Hypoxic perfusion of the glycocalyx was thought to be sufficient to initiate a degradation mechanism of the endothelial barrier. The study found that flow of oxygen throughout the blood vessels did not have to be completely absent (ischemic hypoxia), but that minimal levels of oxygen were sufficient to cause the degradation.
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According to the characteristics of the defect or abnormality, the sclerotic lesion was excised and liquefied fat was aspirated; the excised samples indicated biological changes in the intramammary fat graftsfat necrosis, calcification, hyalinization, and fibroplasia. The complications associated with injecting fat grafts to augment the breasts are like, but less severe, than the medical complications associated with other types of breast procedure. Technically, the use of minuscule (2-mm) incisions and blunt- cannula injection much reduce the incidence of damaging the underlying breast structures (milk ducts, blood vessels, nerves). Injected fat-tissue grafts that are not perfused among the tissues can die, and result in necrotic cysts and eventual calcificationsmedical complications common to breast procedures.
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During retrodialysis, the microdialysis probe is perfused with an analyte-containing solution and the disappearance of drug from the probe is monitored. The recovery for this method can be computed as the ratio of drug lost during passage (Cin−Cout) and drug entering the microdialysis probe (Cin). In principle, retrodialysis can be performed using either the analyte itself (retrodialysis by drug) or a reference compound (retrodialysis by calibrator) that closely resembles both the physiochemical and the biological properties of the analyte. Despite the fact that retrodialysis by drug cannot be used for endogenous compounds as it requires absence of analyte from the sampling site, this calibration method is most commonly used for exogenous compounds in clinical settings.
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After qualifying in medicine in 1967, Poole-Wilson started his career with training posts in London hospitals. In 1973 he was awarded a British-American Research Fellowship, supported by the British Heart Foundation, and undertook research in the well-known heart lab at UCLA, California, then under the chairmanship of Glenn Langer. There he learnt to measure the movement of K, Na and Ca ions in the isolated, but arterially perfused, interventricular preparation which could be made truly ischaemic. He studied the effects of acidosis and ischaemia on myocardial function and Ca exchange and his early results suggested that developed force and Ca exchange were more responsive to acidosis within the cell than to extracellular acidosis.
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At medical centers with a high volume of open aortic surgery, the fastest option for open aortic surgery was sequential aortic clamping or "clamp-and-sew", whereby the aorta was clamped proximally and distally to the diseased segment, and a graft sewn into the intervening segment. This technique leaves the branches of the aorta un- perfused during the time it takes to sew in the graft, potentially increasing the risk of ischemia to the organs which derive their arterial supply from the clamped segment. Critics of this technique advocate intra-operative aortic perfusion. In infrarenal aneurysms, the relative tolerance of the lower extremities to ischemia allows surgeons to clamp distally with low risk of ill effect.
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However to avoid injury the hold cannot be maintained more than a few seconds. When pressure on the carotids is released, the flow of oxygenated blood resumes immediately and consciousness slowly returns. In contrast, if the airway rather than the carotid arteries is blocked, the subject cannot breathe, but his brain is still perfused with blood and he will remain conscious and may continue to struggle for a minute or more; he will lose consciousness only when the oxygen in the circulating blood is consumed and he collapses from hypoxia. Even if the hold is released at this point, the blood circulating through the brain contains no oxygen, and consequently the subject may not regain consciousness or resume spontaneous breathing.
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UDCA-stimulated biliary NO secretion was abolished by the inhibition of iNOS with L-NAME in isolated perfused livers and also in rat livers depleted of GSH with buthionine sulfoximine. Moreover, the biliary secretion of NO species was significantly diminished in UDCA-infused transport mutant [ATP–binding cassette C2/multidrug resistance–associated protein 2–deficient] rats, and this finding was consistent with the involvement of the glutathione carrier ABCC2/Mrp2 in the canalicular transport of GSNO. It was particularly noteworthy that in cultured normal rat cholangiocytes, GSNO activated protein kinase B, protected against apoptosis, and enhanced UDCA-induced ATP release to the medium. Finally, they demonstrated that retrograde GSNO infusion into the common bile duct increased bile flow and biliary bicarbonate secretion.
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Quantitatively, the smooth endoplasmic reticulum of the liver cell is the principal organ of drug metabolism, although every biological tissue has some ability to metabolize drugs. Factors responsible for the liver's contribution to drug metabolism include that it is a large organ, that it is the first organ perfused by chemicals absorbed in the gut, and that there are very high concentrations of most drug-metabolizing enzyme systems relative to other organs. If a drug is taken into the GI tract, where it enters hepatic circulation through the portal vein, it becomes well-metabolized and is said to show the first pass effect. Other sites of drug metabolism include epithelial cells of the gastrointestinal tract, lungs, kidneys, and the skin.
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Peirce argued that logic is the formal study of signs in the broadest sense, not only signs that are artificial, linguistic, or symbolic, but also signs that are semblances or are indexical such as reactions. Peirce held that "all this universe is perfused with signs, if it is not composed exclusively of signs",Peirce, C.S., CP 5.448 footnote, from "The Basis of Pragmaticism" in 1906. along with their representational and inferential relations. He argued that, since all thought takes time, all thought is in signs: > To say, therefore, that thought cannot happen in an instant, but requires a > time, is but another way of saying that every thought must be interpreted in > another, or that all thought is in signs.
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EHNA has been used to study implication of PDE2 in calcium control in cardiac myocytes and has shown to be effective to reverse hypoxic pulmonary vasoconstricion in perfused lung models. EHNA has been therefore been used for two purposes: # to serve as a lead structure for the rational design of more selective and potent PDE2 inhibitors, and # to define some of PDE's biological targets. However, the use of EHNA as a chemical tool in determining the pharmacological role of PDE2 is limited due to its low potency to inhibit PDE2 and high potency in inhibition of adenosine deaminase. Theoretically, this problem can be resolved if the effect of adenosine accumulated by EHNA, a result of adenosine deaminase inhibition, can be accounted and corrected for.
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The interconnected models predict a reduction in gas washout rate with time during decompression compared with the rate predicted for the independent parallel compartment model used for comparison. The Goldman model differs from the Kidd-Stubbs series decompression model in that the Goldman model assumes linear kinetics, where the K-S model includes a quadratic component, and the Goldman model considers only the central well-perfused compartment to contribute explicitly to risk, while the K-S model assumes all compartments to carry potential risk. The DCIEM 1983 model associates risk with the two outermost compartments of a four compartment series. The mathematical model based on this concept is claimed by Goldman to fit not only the Navy square profile data used for calibration, but also predicts risk relatively accurately for saturation profiles.
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High hematocrit blood is stored in the large spleen of deep-diving seals, and may be released into the circulation during a dive, making the spleen an important oxygen reservoir for use during a dive, while reducing blood viscosity when the animal is breathing. Seal muscle has a very high myoglobin concentration, which varies in different muscles and in hooded seals has the capacity to store about six times as much oxygen as humans. Myoglobin has a considerably higher affinity for oxygen than hemoglobin, so if the muscles are perfused during a dive, the oxygen on the myoglobin will only become available when the oxygen level of the blood has been heavily depleted. Although the hooded seal's mass-specific oxygen stores are about four times those of humans, it can dive 20 times longer.
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The oxygen stored is insufficient for aerobic consumption by all tissues, and differential distribution of blood oxygen store to the brain can allow less sensitive tissues to function anaerobically during a dive. Peripheral vasoconstriction largely excludes the skeletal muscles from perfusion during a dive, and use the oxygen stored locally in myoglobin, followed by anaerobic metabolism during a dive. When breathing again, the muscles are perfused and re-oxygenated, and there is a surge in arterial lactate for a short period until reoxygenation stabilises. The problem of how the arteries remain constricted in the presence of increasing tissue pH due to intracellular lactate was found to be avoided by the ability to constrict arteries leading to the organs, rather than arteriole constriction within the organs as occurs in terrestrial animals.
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The "pulseless phase" is characterized by vascular insufficiency from intimal narrowing of the vessels manifesting as arm or leg claudication, renal artery stenosis causing hypertension, and neurological manifestations due to decreased blood flow to the brain. Of note is the function of renal artery stenosis in the causation of high blood pressure: Normally perfused kidneys produce a proportionate amount of a substance called renin. Stenosis of the renal arteries causes hypoperfusion (decreased blood flow) of the juxtaglomerular apparatus, resulting in exaggerated secretion of renin, and high blood levels of aldosterone, eventually leading to water and salt retention and high blood pressure. The neurological symptoms of the disease vary depending on the degree; the nature of the blood vessel obstruction; and can range from lightheadedness to seizures (in severe cases).
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The microdialysis principle was first employed in the early 1960s, when push-pull canulas and dialysis sacs were implanted into animal tissues, especially into rodent brains, to directly study the tissues' biochemistry. While these techniques had a number of experimental drawbacks, such as the number of samples per animal or no/limited time resolution, the invention of continuously perfused dialytrodes in 1972 helped to overcome some of these limitations. Further improvement of the dialytrode concept resulted in the invention of the "hollow fiber", a tubular semipermeable membrane with a diameter of ~200-300μm, in 1974. Today's most prevalent shape, the needle probe, consists of a shaft with a hollow fiber at its tip and can be inserted by means of a guide cannula into the brain and other tissues.
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Bradford Keeney was born in Granite City, Illinois, and grew up in Smithville, Missouri. In May 1969, he won a merit award from the American Medical Association, and later first place at the international science fair with a project called “An Experimental Study of the Effects of Hydrocortisone, Insulin, and Epinephrine on the Glycogen Content of Hepatic Tissues Perfused in Vitro.” This award earned him a scholarship to M.I.T. where he was first introduced to cybernetics and systems thinking. Fascinated by cybernetics, Keeney sought out Gregory Bateson, one of the world’s leading cyberneticians, who became his friend and mentor. Keeney’s doctoral dissertation (Purdue University, 1981) became the book Aesthetics of Change (1983), considered a seminal work in cybernetic theory and heralded by the likes of cybernetician and systems theorist Heinz von Foerster.
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Once a micro-bubble forms it may continue to grow if the tissues are still supersaturated. As the bubble grows it may distort the surrounding tissue and cause damage to cells and pressure on nerves resulting in pain, or may block a blood vessel, cutting off blood flow and causing hypoxia in the tissues normally perfused by the vessel. If a bubble or an object exists which collects gas molecules this collection of gas molecules may reach a size where the internal pressure exceeds the combined surface tension and external pressure and the bubble will grow. If the solvent is sufficiently supersaturated, the diffusion of gas into the bubble will exceed the rate at which it diffuses back into solution, and if this excess pressure is greater than the pressure due to surface tension the bubble will continue to grow.
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For instance, the cannulation of a single microvessel with a micropipette, the microvessel is perfused with a certain pressure, occluded downstream and then the velocity of some cells will be related to the permeability.Michel, C. C., Mason, J. C., Curry, F. E. & Tooke, J. E. Development of Landis Technique for Measuring Filtration Coefficient of Individual Capillaries in Frog Mesentery. Q J Exp Physiol Cms 59, 283-309 (1974).Bates, D. O. & Harper, S. J. Regulation of vascular permeability by vascular endothelial growth factors. Vascul Pharmacol 39, 225-237 (2002) Another technique uses multiphoton fluorescence intravital microscopy through which the flow is related to fluorescence intensity and the permeability is estimated from the Patlak transformation Patlak, C. S., Blasberg, R. G. & Fenstermacher, J. D. Graphical evaluation of blood-to-brain transfer constants from multiple-time uptake data.
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These bubble nuclei are spherical gas phases that are small enough to remain in suspension yet strong enough to resist collapse, their stability being provided by an elastic surface layer consisting of surface-active molecules which resists the effect of surface tension. Once a micro-bubble forms it may continue to grow if the tissues are sufficiently supersaturated. As the bubble grows it may distort the surrounding tissue and cause damage to cells and pressure on nerves resulting in pain, or may block a blood vessel, cutting off blood flow and causing hypoxia in the tissues normally perfused by the vessel. If a bubble or an object exists which collects gas molecules this collection of gas molecules may reach a size where the internal pressure exceeds the combined surface tension and external pressure and the bubble will grow.
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Derivation of the one-dimensional tissue slab model from a uniform tissue perfused by parallel capillaries The assumption that diffusion is the limiting mechanism of dissolved gas transport in the tissues results in a rather different tissue compartment model. In this case a series of compartments has been postulated, with perfusion transport into one compartment, and diffusion between the compartments, which for simplicity are arranged in series, so that for the generalised compartment, diffusion is to and from only the two adjacent compartments on opposite sides, and the limit cases are the first compartment where the gas is supplied and removed via perfusion, and the end of the line, where there is only one neighbouring compartment. The simplest series model is a single compartment, and this can be further reduced to a one-dimensional "tissue slab" model.
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In addition, tetralogy of Fallot may present with other anatomical anomalies, including: # stenosis of the left pulmonary artery, in 40% # a bicuspid pulmonary valve, in 60% # right-sided aortic arch, in 25% # coronary artery anomalies, in 10% # a patent foramen ovale or atrial septal defect, in which case the syndrome is sometimes called a pentalogy of Fallot # an atrioventricular septal defect # partially or totally anomalous pulmonary venous return Tetralogy of Fallot with pulmonary atresia (pseudotruncus arteriosus) is a severe variant in which there is complete obstruction (atresia) of the right ventricular outflow tract, causing an absence of the pulmonary trunk during embryonic development. In these individuals, blood shunts completely from the right ventricle to the left where it is pumped only through the aorta. The lungs are perfused via extensive collaterals from the systemic arteries, and sometimes also via the ductus arteriosus.
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Prior to the introduction of brain death into law in the mid to late 1970s, all organ transplants from cadaveric donors came from non-heart-beating donors (NHBDs). Donors after brain death (DBD) (beating heart cadavers), however, led to better results as the organs were perfused with oxygenated blood until the point of perfusion and cooling at organ retrieval, and so NHBDs were generally no longer used except in Japan, where brain death was not legally, until very recently, or culturally recognized. However, a growing discrepancy between demand for organs and their availability from DBDs has led to a re-examination of using non-heart-beating donors, donors after circulatory death (DCDs), and many centres are now using such donors to expand their potential pool of organs. Tissue donation (corneas, heart valves, skin, bone) has always been possible for NHBDs, and many centres now have established programmes for kidney transplants from such donors.
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More recently, Slavin introduced the use of personalized anti-cancer immunotherapy focusing on the use of activated donor lymphocytes targeted against cancer with monoclonal and bispecific antibodies for efficient elimination of cancer in parallel with induction of long-lasting anti-cancer immunity for prevention of recurrent disease. The use of innovative cell-mediated immunotherapy is now applied in other centers for treatment of otherwise resistant cancer, such as in patients with triple negative breast cancer.Triple Negative Breast Cancer: a Highly Significant Finding, MossReports In parallel with the growing activities of Slavin's center and his international impact in cell therapy, new approaches were developed for induction of transplantation tolerance of host-vs-graft and graft-vs-host towards developing improved methods for allogeneic blood or marrow transplantation as well as transplantation of cellular and perfused organ allografts. Initially, Slavin pioneered the use of monoclonal antibodies anti-CD52 (Alemtuzumab, now approved by FDA as Lemtrada) for prevention of graft-vs-host disease (GVHD), the most serious complication of allogeneic stem cell transplantation, and later on for treatment of CLL and multiple sclerosis.
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