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Sample records for artificial arterial blood

  1. Artificial blood

    Directory of Open Access Journals (Sweden)

    Sarkar Suman

    2008-01-01

    Full Text Available Artificial blood is a product made to act as a substitute for red blood cells. While true blood serves many different functions, artificial blood is designed for the sole purpose of transporting oxygen and carbon dioxide throughout the body. Depending on the type of artificial blood, it can be produced in different ways using synthetic production, chemical isolation, or recombinant biochemical technology. Development of the first blood substitutes dates back to the early 1600s, and the search for the ideal blood substitute continues. Various manufacturers have products in clinical trials; however, no truly safe and effective artificial blood product is currently marketed. It is anticipated that when an artificial blood product is available, it will have annual sales of over $7.6 billion in the United States alone.

  2. Artificial blood.

    Science.gov (United States)

    Sarkar, Suman

    2008-07-01

    Artificial blood is a product made to act as a substitute for red blood cells. While true blood serves many different functions, artificial blood is designed for the sole purpose of transporting oxygen and carbon dioxide throughout the body. Depending on the type of artificial blood, it can be produced in different ways using synthetic production, chemical isolation, or recombinant biochemical technology. Development of the first blood substitutes dates back to the early 1600s, and the search for the ideal blood substitute continues. Various manufacturers have products in clinical trials; however, no truly safe and effective artificial blood product is currently marketed. It is anticipated that when an artificial blood product is available, it will have annual sales of over $7.6 billion in the United States alone.

  3. Artificial blood.

    OpenAIRE

    1983-01-01

    #Blood substitutes have been developed for almost a century. The various type of artificial blood was continuously available on the market. The theme of this report is to identify the best substitute in emergency situation for some patients and science students. The definition of best is given; thus, as the vital part of the report, the comparison between them is described and discussed. Modified hemoglobin, bovine-based hemoglobin and PFCs are three basic types. In terms of the perfor...

  4. Middle cerebral artery blood velocity during rowing

    DEFF Research Database (Denmark)

    Secher, Niels Henry; Pott, F; Knudsen, L.;

    1997-01-01

    original,arterial blood pressure,central venous pressure,cerebral blood flow, exercise, transcranial Doppler......original,arterial blood pressure,central venous pressure,cerebral blood flow, exercise, transcranial Doppler...

  5. Another Step Closer to Artificial Blood

    Science.gov (United States)

    ... news/fullstory_162357.html Another Step Closer to Artificial Blood Synthetic product could save lives on battlefield and ... 5, 2016 SATURDAY, Dec. 3, 2016 (HealthDay News) -- Artificial blood stored as a powder could one day revolutionize ...

  6. Continuous blood gas monitoring in femoral arteries

    Science.gov (United States)

    Schlain, Les A.; Spar, Steven M.; Dellinger, Bart

    1995-05-01

    Continuous intra-arterial blood gas monitoring is a potentially valuable tool in the surgical and intensive care arenas. Patient oxygenation and acid base status can change rapidly and without warning. The ability to monitor pHa, PaCO2 and PaO2 in arterial blood will be a major medical advance for the anesthesiologist and intensivist. Intra-arterial blood gas sensors are typically placed in radial arteries. In certain patient populations accurate monitoring is not possible in radial arteries due to arterial environmental factors such as hypotension, vasoconstriction and atherosclerotic disease. These same factors can make radial cannulation difficult resulting in traumatic catheter insertion, thereby further compromising flow conditions. In situations where radial artery flow is expected to be compromised, selecting a large vessel for sensor placement is desirable. We report an initial feasibility study of our blood gas monitoring system using the femoral artery as the sensing site. Clinical results are presented as well as potential advantages and disadvantages associated with monitoring in the femoral artery.

  7. Blood tracer kinetics in the arterial tree.

    Directory of Open Access Journals (Sweden)

    Elias Kellner

    Full Text Available Evaluation of blood supply of different organs relies on labeling blood with a suitable tracer. The tracer kinetics is linear: Tracer concentration at an observation site is a linear response to an input somewhere upstream the arterial flow. The corresponding impulse response functions are currently treated empirically without incorporating the relation to the vascular morphology of an organ. In this work we address this relation for the first time. We demonstrate that the form of the response function in the entire arterial tree is reduced to that of individual vessel segments under approximation of good blood mixing at vessel bifurcations. The resulting expression simplifies significantly when the geometric scaling of the vascular tree is taken into account. This suggests a new way to access the vascular morphology in vivo using experimentally determined response functions. However, it is an ill-posed inverse problem as demonstrated by an example using measured arterial spin labeling in large brain arteries. We further analyze transport in individual vessel segments and demonstrate that experimentally accessible tracer concentration in vessel segments depends on the measurement principle. Explicit expressions for the response functions are obtained for the major middle part of the arterial tree in which the blood flow in individual vessel segments can be treated as laminar. When applied to the analysis of regional cerebral blood flow measurements for which the necessary arterial input is evaluated in the carotid arteries, present theory predicts about 20% underestimation, which is in agreement with recent experimental data.

  8. Blood tracer kinetics in the arterial tree.

    Science.gov (United States)

    Kellner, Elias; Gall, Peter; Günther, Matthias; Reisert, Marco; Mader, Irina; Fleysher, Roman; Kiselev, Valerij G

    2014-01-01

    Evaluation of blood supply of different organs relies on labeling blood with a suitable tracer. The tracer kinetics is linear: Tracer concentration at an observation site is a linear response to an input somewhere upstream the arterial flow. The corresponding impulse response functions are currently treated empirically without incorporating the relation to the vascular morphology of an organ. In this work we address this relation for the first time. We demonstrate that the form of the response function in the entire arterial tree is reduced to that of individual vessel segments under approximation of good blood mixing at vessel bifurcations. The resulting expression simplifies significantly when the geometric scaling of the vascular tree is taken into account. This suggests a new way to access the vascular morphology in vivo using experimentally determined response functions. However, it is an ill-posed inverse problem as demonstrated by an example using measured arterial spin labeling in large brain arteries. We further analyze transport in individual vessel segments and demonstrate that experimentally accessible tracer concentration in vessel segments depends on the measurement principle. Explicit expressions for the response functions are obtained for the major middle part of the arterial tree in which the blood flow in individual vessel segments can be treated as laminar. When applied to the analysis of regional cerebral blood flow measurements for which the necessary arterial input is evaluated in the carotid arteries, present theory predicts about 20% underestimation, which is in agreement with recent experimental data.

  9. Middle cerebral artery blood velocity during running

    DEFF Research Database (Denmark)

    Lyngeraa, Tobias; Pedersen, Lars Møller; Mantoni, T;

    2013-01-01

    Running induces characteristic fluctuations in blood pressure (BP) of unknown consequence for organ blood flow. We hypothesized that running-induced BP oscillations are transferred to the cerebral vasculature. In 15 healthy volunteers, transcranial Doppler-determined middle cerebral artery (MCA....... During running, rhythmic oscillations in arterial BP induced by interference between HR and step frequency impact on cerebral blood velocity. For the exercise as a whole, average MCA velocity becomes elevated. These results suggest that running not only induces an increase in regional cerebral blood flow...

  10. NONLINEAR ELASTICITY OF BLOOD ARTERIAL DUCT

    Institute of Scientific and Technical Information of China (English)

    黄孟才; 顾忠; 沈俊; 唐复勇

    1991-01-01

    The paper deals with nonlinear elasticity of blood arterial duct, in which the artery is modeled to bea locally triclinic, transverse isotropic, incorapressible, axisymmetric and thickwalled tube with large deformations, The nonlinear coustitutive relationship of arterial tissues is based on the theorv of Green and Adkins. A nonlinear strain energy density function is introduced for nonlinear stress-strain relationship of second order, in which the coefficient of each term is expressed by means of a Lame’s constant, The elasticity constants are nqcessary to describe such a uonlinear finite strain etastieity of the second order, These constants are determined by means of the stress-strain increment theory.

  11. ANALYSIS OF PULSATILE BLOOD FLOW IN AXIALLY MOVING ARTERIES

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    In order to study motional properties of pulsatile blood flow in axially moving arteries, the authors derived some expressions of the pulsatile blood flow from the basic equations of motion for blood and vascular walls, including an axial blood velocity equation, a flow rate equation and a wall shear stress equation, which described not only the overall axial movement of the arteries but also the elastic properties of the vascular walls, discussed the effects of the arterial wall elasticity on the wall shear stress in coronary arteries in terms of these expressions, and analyzed changes of motional properties of pulsatile blood flow between an elastic arterial tube model and a rigid tube model. The results proved the inference by J.E. Moore Jr. et al. (1994) that the axial movement of arteries be as important in determining coronary artery hemodynamics as the elastic property of the vascular wall.

  12. 20 CFR 718.105 - Arterial blood-gas studies.

    Science.gov (United States)

    2010-04-01

    ... gas exchange. This defect will manifest itself primarily as a fall in arterial oxygen tension either... 20 Employees' Benefits 3 2010-04-01 2010-04-01 false Arterial blood-gas studies. 718.105 Section... DEATH DUE TO PNEUMOCONIOSIS Criteria for the Development of Medical Evidence § 718.105 Arterial...

  13. Penetration of an artificial arterial thromboembolism in a live animal using an intravascular therapeutic microrobot system.

    Science.gov (United States)

    Jeong, Semi; Choi, Hyunchul; Go, Gwangjun; Lee, Cheong; Lim, Kyung Seob; Sim, Doo Sun; Jeong, Myung Ho; Ko, Seong Young; Park, Jong-Oh; Park, Sukho

    2016-04-01

    The biomedical applications of wireless robots are an active area of study. In addition to moving to a target lesion, wireless locomotive robots can deliver a therapeutic drug for a specific disease. Thus, they hold great potential as therapeutic devices in blood vessel diseases, such as thrombi and occlusions, and in other diseases, such as cancer and inflammation. During a percutaneous coronary intervention (PCI), surgeons wear a heavy shielding cloth. However, they cannot escape severe radiation exposure owing to unstable shielding. They may also suffer from joint pains because of the weight of the shielding cloth. In addition, the catheters in PCIs are controlled by the surgeon's hand. Thus, they lack steering ability. A new intravascular therapeutic system is needed to address these problems in conventional PCIs. We developed an intravascular therapeutic microrobot system (ITMS) using an electromagnetic actuation (EMA) system with bi-plane X-ray devices that can remotely control a robot in blood vessels. Using this proposed ITMS, we demonstrated the locomotion of the robot in abdominal and iliac arteries of a live pig by the master-slave method. After producing an arterial thromboembolism in a live pig in a partial iliac artery, the robot moved to the target lesion and penetrated by specific motions (twisting and hammering) of the robot using the proposed ITMS. The results reveal that the proposed ITMS can realize stable locomotion (alignment and propulsion) of a robot in abdominal and iliac arteries of a live pig. This can be considered the first preclinical trial of the treatment of an artificial arterial thromboembolism by penetration of a blood clot.

  14. DETERMINATION OF AMMONIA IN EAR-LOBE CAPILLARY BLOOD IS AN ALTERNATIVE TO ARTERIAL BLOOD AMMONIA

    NARCIS (Netherlands)

    HUIZENGA, [No Value; GIPS, CH; CONN, HO; JANSEN, PLM

    1995-01-01

    Blood ammonia determination is a laboratory test to diagnose hepatic encephalopathy. Arterial blood is superior to peripheral venous blood ammonia because of ammonia metabolism in muscle. We have compared capillary with arterial whole blood ammonia as capillary sampling is an attractive alternative.

  15. Investigation on artificial blood or substitute blood replace the natural blood.

    Science.gov (United States)

    Keyhanian, Sh; Ebrahimifard, M; Zandi, M

    2014-01-01

    Blood is a liquid tissue in which dissolved with abundant chemical factors and millions of different cells The reduction of unwanted side effects, especially diseases that emerge through blood such as HIV and hepatitis, has a significant role for modern medicine of transfusion and transplantation. The issues and costs of human blood collection and storage, direct this procedure towards the use of alternatives blood. Two important research fields of this area were oxygen carriers based on hemoglobin and perfluoro chemicals. While they do not have the same quality as the blood cell products, the oxygen carrier solutions have potential clinical and non-clinical applications. The result showed that these products can reach to the body tissues easier than normal red blood cells, and can control the oxygen directly. The final aim of transfusion is to establish a transfusion system with no side effects, and the fact that oxygen carrier artificial blood has this property. The article attempts to step towards solving some problems of blood transfusion through describing the properties of artificial blood alternatives.

  16. Pulmonary artery rupture in a patient receiving an orthotopic heart transplant after total artificial heart explant.

    Science.gov (United States)

    Nomoto, Koichi; Weiner, Menachem M; Evans, Adam

    2014-02-01

    Our case illustrates a patient who suffered a pulmonary artery rupture despite previous total artificial heart implantation and replacement with orthotopic heart transplant. Pulmonary artery rupture during or following cardiac surgery has been reported to occur due to both pulmonary artery catheter use and surgical technique. Our case is the first to demonstrate the occurrence of this complication in the total artificial heart patient population.

  17. Gender differences in blood pressure regulation following artificial gravity exposure

    Science.gov (United States)

    Evans, Joyce; Goswami, Nandu; Kostas, Vladimir; Zhang, Qingguang; Ferguson, Connor; Moore, Fritz; Stenger, Michael, , Dr; Serrador, Jorge; W, Siqi

    Introduction. Before countermeasures to space flight cardiovascular deconditioning are established, gender differences in cardiovascular responses to orthostatic stress, in general, and to orthostatic stress following exposure to artificial gravity (AG), in particular, need to be determined. Our recent determination that a short exposure to AG improved the orthostatic tolerance limit (OTL) of cardiovascularly deconditioned subjects drives the current effort to determine mechanisms of that improvement in men and in women. Methods. We determined the OTL of 9 men and 8 women following a 90 min exposure to AG compared to that following 90 min of head down bed rest (HDBR). On both days (21 days apart), subjects were made hypovolemic (low salt diet plus 20 mg intravenous furosemide) and orthostatic tolerance was determined from a combination of head up tilt and increasing lower body negative pressure until presyncope. Mean values and correlations with OTL were determined for heart rate, blood pressure, stroke volume, cardiac output, total peripheral resistance (Finometer), middle cerebral artery flow velocity (DWL), partial pressure of carbon dioxide (Novametrics) and body segmental impedance (UFI THRIM) at supine baseline, during orthostatic stress to presyncope and at supine recovery. Results. Orthostatic tolerance of these hypovolemic subjects was significantly greater following AG than following HDBR. Exposure to AG increased cardiac output in both men and women and increased stroke volume in women. In addition, AG decreased systolic blood pressure in men, but not women, and increased cerebral flow in women, but not men. In both men and women, AG exposure decreased peripheral resistance and decreased cerebrovascular resistance in women. Men’s heart rate rose more at the end of OTL on their AG, compared to their HDBR, day but women’s fell. Presyncopal stroke volume reached the same level on each day of study for both men and women. Conclusions. In the present

  18. [Ultrasonographic study of blood flow in the renal arteries of patients with arterial hypertension].

    Science.gov (United States)

    Makarenko, E S; Dombrovskiĭ, V I; Nelasov, N Iu

    2012-01-01

    Vascular duplex ultrasound duplex with simultaneous ECG registration was made to estimate the quantitative and time parameters of blood flow in the renal arteries with grade 1-2 arterial hypertension. There were increases in vascular resistance indices and acceleration phase index and a reduction in systolic phase index. There were correlations of the time parameters of blood flow in the renal arteries with age and lipidogram values.

  19. Measuring blood oxygenation of pulsatile arteries using photoacoustic microscopy

    Science.gov (United States)

    Li, Qian; Yu, Tianhao; Li, Lin; Chai, Xinyu; Zhou, Chuanqing

    2016-10-01

    Heart pumps blood through the blood vessels to provide body with oxygen and nutrients. As the result, the blood flow, volume and oxygenation in arteries has a pulsatile nature. Measuring these pulsatile parameters enables more precise monitoring of oxygen metabolic rate and is thus valuable for researches and clinical applications. Photoacoustic microscopy (PAM) is a proven label-free method for in vivo measuring blood oxygenation at single blood vessel level. However, studies using PAM to observe the pulsatile nature of blood oxygenation in arteries were not reported. In this paper, we use optical-resolution PAM (OR-PAM) technology to study the blood oxygenation dynamics of pulsatile arteries. First, the ability of our OR-PAM system to accurately reflect the change of optical absorption in imaged objects is demonstrated in a phantom study. Then the system is used to image exposed cortical blood vessels of cat. The pulsatile nature of blood volume and oxygenation in arteries is clearly reflected in photoacoustic (PA) signals, whereas it's not observable in veins. By using a multi-wavelength laser, the dynamics of the blood oxygenation of pulsatile arteries in cardiac cycles can be measured, based on the spectroscopic method.

  20. Differences in superior thyroid artery and inferior thyroid artery blood flow spectrum parameters in subacute thyroiditis

    Institute of Scientific and Technical Information of China (English)

    Jin-Bo Li

    2016-01-01

    Objective:To study the differences in superior thyroid artery and inferior thyroid artery blood flow spectrum parameters in subacute thyroiditis. Methods:A Total of 40 cases of patients with subacute thyroiditis and 40 cases of healthy volunteers were selected for study and enrolled in pathology group and control group respectively, color Doppler ultrasonography was conducted to detect peak blood flow velocities (Vmax) of superior thyroid artery and inferior thyroid artery as well as resistance index (RI), and serum was collected to detect thyroid hormone contents, infection indexes and oxidative stress indexes. Results:Peak blood flow velocities Vmax of superior thyroid artery and inferior thyroid artery of pathology group were significantly higher than those of control group, and resistance index RI was not different from that of control group;FT3, FT4, TT3, TT4, ESR, CRP, PCT and MDA of pathology group were significantly higher than those of control group, and SOD and TAOC were significantly lower than those of control group;Vmax of superior thyroid artery and inferior thyroid artery were positively correlated with FT3, FT4, TT3, TT4, ESR, CRP, PCT and MDA, and negatively correlated with SOD and TAOC. Conclusion:Peak blood flow velocities (Vmax) of superior thyroid artery and inferior thyroid artery in subacute thyroiditis are significantly accelerated, Vmax has good consistency with thyroid hormone contents, infection indexes and oxidative stress indexes, and it can accurately assess the severity of the disease.

  1. [Artificial blood - coming soon or never reaching clinical maturity?].

    Science.gov (United States)

    Schöler, M; Frietsch, T; Jambor, C; Knels, R

    2010-03-01

    Formerly developed resuscitation fluids solely imitated the main function of the blood -oxygen transport. A research driven by the army requested an oxygen carrier that does not need cross typing and cooled storage. Artificial oxygen carriers (AOC) use either the molecular oxygen bondage to hemoglobin: HBOC- "hemoglobin based oxygen carriers" or the physical dissolution of oxygen in the blood plasma compartment by hyperbaric pressure in perfluorocarbon emulsions (PFC). Decades of preclinical and clinical research did pass but the results were disappointing- in Russia, a not well designed PFC is available locally and the only approved HBOC in South Africa is not being used much. Other products, just prior to filing for FDA approval, did not achieve convincing study results and research and production was stopped. Some trials have been stopped by the FDA for safety reasons, half of trials with the primary endpoint reduction of allogeneic transfusion requirement were unsuccessful or offset by an increased blood requirement later. However, some ventures currently are trying to use the knowledge gained so far and are investigating third and fourth generation products of artificial blood components. These imitate the cellular structure of red cells as micells, nanocapsules, (ABC- artificial blood cells) or gas bubbles (microbubbles), admixture of volume substitutes such as starches, gelatin or albumin or use hyperbaric oxygenation [38]. Artificial platelets are in clinical phase IIa, recombinant albumin in phase III. In this article, a short overview about the current situation on artificial blood products is given. The critical point for the break through for artificial blood products did not come yet but could be ahead-

  2. Analysis of CHIKV in Mosquitoes Infected via Artificial Blood Meal.

    Science.gov (United States)

    Ledermann, Jeremy P; Powers, Ann M

    2016-01-01

    Having a mechanism to assess the transmission dynamics of a vector-borne virus is one critical component of understanding the life cycle of these viruses. Laboratory infection systems using artificial blood meals is one valuable approach for monitoring the progress of virus in its mosquito host and evaluating potential points for interruption of the cycle for control purposes. Here, we describe an artificial blood meal system with Chikungunya virus (CHIKV) and the processing of mosquito tissues and saliva to understand the movement and time course of virus infection in the invertebrate host.

  3. Prediction of arterial blood gas values from arterialized earlobe blood gas values in patients treated with mechanical ventilation

    Directory of Open Access Journals (Sweden)

    Honarmand Azim

    2008-01-01

    Full Text Available Background/Objective: Arterial blood gas (ABG analysis is useful in evaluation of the clinical condition of critically ill patients; however, arterial puncture or insertion of an arterial catheter may sometimes be difficult and cause many complications. Arterialized ear lobe blood samples have been described as adequate to gauge gas exchange in acute and chronically ill pediatric patients. Purpose: This study evaluates whether pH, partial pressure of oxygen (PO 2 , partial pressure of carbon dioxide (PCO 2 , base excess (BE, and bicarbonate (HCO 3 values of arterialized earlobe blood samples could accurately predict their arterial blood gas analogs for adult patients treated by mechanical ventilation in an intensive care unit (ICU. Setting: A prospective descriptive study Methods: Sixty-seven patients who were admitted to ICU and treated with mechanical ventilation were included in this study. Blood samples were drawn simultaneously from the radial artery and arterialized earlobe of each patient. Results: Regression equations and mean percentage-difference equations were derived to predict arterial pH, PCO 2 , PO 2 , BE, and HCO 3 -values from their earlobe analogs. pH, PCO 2 , BE, and HCO 3 all significantly correlated in ABG and earlobe values. In spite of a highly significant correlation, the limits of agreement between the two methods were wide for PO 2 . Regression equations for prediction of pH, PCO 2 , BE, and HCO3- values were: arterial pH (pHa = 1.81+ 0.76 x earlobe pH (pHe [r = 0.791, P < 0.001]; PaCO 2 = 1.224+ 1.058 x earlobePCO 2 (PeCO 2 [r = 0.956, P < 0.001]; arterial BE (BEa = 1.14+ 0.95 x earlobe BE (BEe [r= 0.894, P < 0.001], and arterial HCO 3 - (HCO 3 -a = 1.41+ earlobe HCO 3 (HCO 3 -e [r = 0.874, P < 0.001]. The predicted ABG values from the mean percentage-difference equations were derived as follows: pHa = pHe x 1.001; PaCO 2 = PeCO 2 x 0.33; BEa = BEe x 0.57; and HCO 3 -a = HCO 3 -e x 1.06. Conclusions: Arterialized

  4. [Chronobiology of blood pressure and chronopharmacotherapy of arterial hypertension].

    Science.gov (United States)

    Schmieder, R E; Bramlage, P; Schunkert, H

    2012-02-01

    Arterial blood pressure is subject to a circadian rhythm that results in a fall of blood pressure during the night. In patients with diabetes, renal insufficiency, left-ventricular hypertrophy, sleep apnea, hypertension of pregnancy, and different forms of secondary hypertension a nocturnal fall of blood pressure is even abandoned or reverted. Diagnosis is made using 24-h blood pressure measurement, which is however used not frequently enough for a clinical assessment or adjustment of therapy. An adaption of the selection or the time of administration of antihypertensive drugs with respect to the circadian rhythm is beneficial to control blood pressure and reduce cardiovascular morbidity. This is particularly true for patients with an a non- or inverted dipping blood pressure pattern, in which the bedtime dosing may result in a normalization of blood pressure and restoration of a normal circadian rhythm. The present manuscript reviews the chronopharmacotherapy of arterial hypertension and grant practical recommendations for their translation into clinical practice.

  5. Undisplayed Bicarbonate ion Concentration in Arterial Blood Gas Analysis

    OpenAIRE

    2013-01-01

    Blood bicarbonate ion concentration (BcHCO3-) is a vital parameter in the management of acid base disorders. In an arterial blood gas (ABG) analyzer, the BcHCO3- is calculated from the values of pH and pCO2.

  6. Heart and Artery Damage and High Blood Pressure

    Science.gov (United States)

    ... Artery Disease Venous Thromboembolism Aortic Aneurysm More How High Blood Pressure Can Lead to a Heart Attack Updated:Dec ... sheet This content was last reviewed October 2016. High Blood Pressure • Home • Get the Facts About HBP • Know Your ...

  7. Middle cerebral artery blood velocity and plasma catecholamines during exercise

    DEFF Research Database (Denmark)

    Pott, F; Jensen, K; Hansen, H;

    1996-01-01

    During dynamic exercise, mean blood velocity (Vmean) in the middle cerebral artery (MCA) demonstrates a graded increase to work rate and reflects regional cerebral blood flow. At a high work rate, however, vasoactive levels of plasma catecholamines could mediate vasoconstriction of the MCA...

  8. PERFORMANCE MODELING AND ANALYSIS OF BLOOD FLOW IN ELASTIC ARTERIES

    Institute of Scientific and Technical Information of China (English)

    Anil Kumar; C.L. Varshney; G.C. Sharma

    2005-01-01

    Two different non-Newtonian models for blood flow are considered, first a simple power law model displaying shear thinning viscosity, and second a generalized Maxwell model displaying both shear thinning viscosity and oscillating flow viscous-elasticity. These models are used along with a Newtonian model to study sinusoidal flow of blood in rigid and elastic straight arteries in the presence of magnetic field. The elasticity of blood does not appear to influence its flow behavior under physiological conditions in the large arteries,purely viscous shear thinning model should be quite realistic for simulating blood flow under these conditions. On using the power law model with high shear rate for sinusoidal flow simulation in elastic arteries, the mean and amplitude of the flow rate were found to be lower for a power law fluid compared to Newtonian fluid for the same pressure gradient. The governing equations have been solved by Crank-Niclson scheme. The results are interpreted in the context of blood in the elastic arteries keeping the magnetic effects in view. For physiological flow simulation in the aorta, an increase in mean wall shear stress, but a reduction in peak wall shear stress were observed for power law model compared to a Newtonian fluid model for matched flow rate wave form. Blood flow in the presence of transverse magnetic field in an elastic artery is investigated and the influence of factors such as morphology and surface irregularity is evaluated.

  9. [Umbilical artery blood gases of term neonates at altitude].

    Science.gov (United States)

    Villamonte, Wilfredo; Escalante, Darío; Yabar, Janet; Jerí, María; Peralta, Paola; Ochoa, Robert

    2014-01-01

    In order to determine the normal values of arterial blood gases in the umbilical artery of term infants at 3400 m altitude, a cross-sectional study was conducted. It was performed in the umbilical artery blood of 300 term infants, with an adequate gestational age and whose birth took place between January 2010 and December 2011 at the Essalud National Hospital Adolfo Guevara Velazco (Cusco, Peru). It was found that the average pH of healthy term infants was 7.33 ± 0.07; the values for percentiles 5 and 95 were 7.18 and 7.40 respectively. Tables with the 5th and 95th percentiles for pH, pO2, pCO2, SO2, p50, base excess and HCO3 of the umbilical artery of term infants at 3400 m altitude are provided.

  10. Mathematical arterialization of venous blood in emergency medicine patients

    DEFF Research Database (Denmark)

    Tygesen, Gitte Boier; Matzen, Helle; Grønkjær, Karen;

    2012-01-01

    .83; and Bland-Altman limits of agreement well within the limits of acceptable laboratory and clinical performance. The calculated values of arterial PO2 followed a set of predefined rules relating calculated and measured PO2 levels in all cases. The method represents an improvement on the use of venous blood......OBJECTIVES: Arterial punctures represent a painful and unpleasant experience. Acid-base and oxygenation status can be assessed from peripheral venous blood, but agreement with arterial values is not always clinically acceptable. This study evaluates a method for mathematically transforming...... alone where the correlation coefficients were as follows: group A, pH 0.85, PCO2 0.88; group B, pH 0.79, PCO2 0.59; and limits of agreement for PCO2 at the border of (group A) or beyond (group B) acceptable clinical limits. CONCLUSION: Application of the mathematical arterialization method may reduce...

  11. Influence of Artificial Sweetener on Human Blood Glucose Concentration

    Directory of Open Access Journals (Sweden)

    Ilse Skokan

    2007-01-01

    Full Text Available Artificial sweeteners, such as saccharin or cyclamic acid are synthetically manufactured sweetenings. Known for their low energetic value they serve especially diabetic and adipose patients as sugar substitutes. It has been hypothesized that the substitution of sugar with artificial sweeteners may induce a decrease of the blood glucose. The aim of this study was to determine the reliability of this hypothesis by comparing the influence of regular table sugar and artificial sweeteners on the blood glucose concentration. In this pilot-study 16 patients were included suffering from adiposity, pre-diabetes and hypertension. In the sense of a cross-over design, three test trials were performed at intervals of several weeks. Each trial was followed by a test free interval. Within one test trial each patient consumed 150 ml test solution (water that contained either 6 g of table sugar (“Kandisin” with sweetener free serving as control group. Tests were performed within 1 hr after lunch to ensure conditions comparable to patients having a desert. Every participant had to determine their blood glucose concentration immediately before and 5, 15, 30 and 60 minutes after the intake of the test solution. For statistics an analysis of variance was performed. The data showed no significant changes in the blood glucose concentration. Neither the application of sugar (F4;60 = 1.645; p = .175 nor the consumption of an artificial sweetener (F2.068;31.023 = 1.551; p > .05 caused significant fluctuations in the blood sugar levels. Over a time frame of 60 minutes in the control group a significant decrease of the blood sugar concentration was found (F2.457;36.849 = 4.005; p = .020 as a physiological reaction during lunch digestion.

  12. RELATIONS OF ENDOTHELIAL FUNCTION AND BLOOD FLOW IN BRACHIAL ARTERY AND CORONARY ARTERY

    Institute of Scientific and Technical Information of China (English)

    孙寅光; 沈卫峰; 施仲伟; 张大东

    2003-01-01

    Objective To determine the relations between endothelium dependent vasodilator function and blood flow in the brachial and coronary arteries in patients with suspected coronary artery disease.MethodsTwenty eight patients with suspected coronary artery disease underwent brachial artery endothelial function test by using high resolution B mode ultrasound before coronary angiography (CAG) and coronary flow reserve (CFR) test by using intracoronary Doppler technique. The correlation of coronary artery dilatation induced by an increase in blood flow after intracoronary adenosine infusion and brachial artery flow mediated dilatation (FMD) following reactive hyperemia was evaluated. The relation between the change of brachial artery blood flow and CFR was also studied.ResultsThere was a positive correlation between brachial FMD and percent change of coronary diameter after adenosine infusion (12.50%±9.35% vs 11.38%±7.55%, r=0.425,P=0.02). There was also a weak negative relation between brachial flow change following reactive hyperemia and CFR (r=0.397, P=0.04).ConclusionThere is a correlation between the coronary endothelial function and the CFR by ultrasonic determination of brachial flow changes following reactive hyperemia.

  13. Magnetic sensor for arterial distension and blood pressure monitoring.

    Science.gov (United States)

    Ruhhammer, Johannes; Herbstritt, Tamara; Ruh, Dominic; Foerster, Katharina; Heilmann, Claudia; Beyersdorf, Friedhelm; Goldschmidtboeing, Frank; Seifert, Andreas; Woias, Peter

    2014-12-01

    A novel sensor for measuring arterial distension, pulse and pressure waveform is developed and evaluated. The system consists of a magnetic sensor which is applied and fixed to arterial vessels without any blood vessel constriction, hence avoiding stenosis. The measurement principle could be validated by in vitro experiments on silicone tubes, and by in vivo experiments in an animal model, thereby indicating the non-linear viscoelastic characteristics of real blood vessels. The sensor is capable to provide absolute measurements of the dynamically varying arterial diameter. By calibrating the sensor, a long-term monitoring system for continuously measuring blood pressure and other cardiovascular parameters could be developed based on the method described. This will improve diagnostics for high risk patients and enable a better, specific treatment.

  14. Noninvasive 24-hour ambulatory arterial blood pressure monitoring in cirrhosis

    DEFF Research Database (Denmark)

    Møller, Søren; Wiinberg, N; Henriksen, Jens Henrik

    1995-01-01

    Cirrhotic patients have disturbed systemic hemodynamics with reduced arterial blood pressure, but this has not been investigated during daily activity and sleep. Systolic (SBP), diastolic (DBP), and mean arterial blood pressure (MAP), and heart rate (HR) were measured by an automatic ambulant...... device for monitoring blood pressure in 35 patients with cirrhosis and 35 healthy matched controls. During the daytime, SBP, DBP, and MAP were significantly lower in the patients than in the controls (median 118 vs. 127; 70 vs. 78; 86 vs. 94 mm Hg, P blood pressures...... were almost similar in the two groups (108 vs. 110; 65 vs. 67; 78 vs. 82 mm Hg, NS). Conversely, HR was significantly higher in the patients both in the daytime (86 vs. 72/min, P blood pressure and HR from daytime...

  15. Harmonics tracking of intracranial and arterial blood pressure waves.

    Science.gov (United States)

    Shahsavari, Sima; McKelvey, Tomas

    2008-01-01

    Considering cardiorespiratory interaction and heart rate variability, a new approach is proposed to decompose intracranial pressure and arterial blood pressure to their different harmonics. The method is based on tracking the amplitudes of the harmonics by a Kalman filter based tracking algorithm. The algorithm takes benefit of combined frequency estimation technique which uses both Fast Fourier Transform and RR-interval detection. The result would be of use in intracranial pressure and arterial blood pressure waveform analysis as well as other investigations which need to estimate contribution of specific harmonic in above mentioned signals such as Pressure-Volume Compensatory Reserve assessment.

  16. Investigation on artificial blood vessels prepared from bacterial cellulose.

    Science.gov (United States)

    Zang, Shanshan; Zhang, Ran; Chen, Hua; Lu, Yudong; Zhou, Jianhai; Chang, Xiao; Qiu, Guixing; Wu, Zhihong; Yang, Guang

    2015-01-01

    BC (bacterial cellulose) exhibits quite distinctive properties than plant cellulose. The outstanding properties make BC a promising material for preparation of artificial blood vessel. By taking advantage of the high oxygen permeability of PDMS (polydimethylsiloxane) as a tubular template material, a series of BC tubes with a length of 100 mm, a thickness of 1mm and an outer diameter of 4 or 6mm were biosynthesized with the help of Gluconacetobacter xylinum. Through characterization by SEM (scanning electron microscope), tensile testing and thermal analysis, it is demonstrated that BC tubes are good enough for artificial blood vessel with elaborated nano-fiber architecture, qualified mechanical properties and high thermal stability. In addition, measurement of biocompatibility also shows that BC tubes are greatly adaptable to the in vivo environment. The results indicate that BC tubes have great potential for being utilized as tubular scaffold materials in the field of tissue engineering.

  17. Right hepatic artery crossing the common hepatic artery: an unusual blood supply to the liver.

    Science.gov (United States)

    Felli, Emanuele; Vennarecci, Giovanni; Santoro, Roberto; Guglielmo, Nicola; Ettorre, Giuseppe Maria

    2016-04-01

    To perform hepatic surgery a precise preoperative and intraoperative study of liver vascular supply is mandatory. Detecting vascular variations may have great importance on surgical strategy and outcome, and details of anatomy do not concern only academical knowledge but become deeply involved in practice. We present a case of unusual blood supply to the liver, the common hepatic artery was directed to the right liver and a right hepatic artery originating from the superior mesenteric artery was directed to the left liver. The right hepatic artery crossed the common hepatic artery in the proximal part of the hepatic pedicle, anterior to the portal vein. To our knowledge this type of anatomical variation has not been described before and it represents a rare finding that has to be kept in mind, especially in case of major hepatectomies and more demanding splitting liver procedures such as A.L.P.P.S., in situ split, ex situ split and living donor liver transplantation.

  18. Spontaneous oscillations of capillary blood flow in artificial microvascular networks.

    Science.gov (United States)

    Forouzan, Omid; Yang, Xiaoxi; Sosa, Jose M; Burns, Jennie M; Shevkoplyas, Sergey S

    2012-09-01

    Previous computational studies have suggested that the capillary blood flow oscillations frequently observed in vivo can originate spontaneously from the non-linear rheological properties of blood, without any regulatory input. Testing this hypothesis definitively in experiments involving real microvasculature has been difficult because in vivo the blood flow in capillaries is always actively controlled by the host. The objective of this study was to test the hypothesis experimentally and to investigate the relative contribution of different blood cells to the capillary blood flow dynamics under static boundary conditions and in complete isolation from the active regulatory mechanisms mediated by the blood vessels in vivo. To accomplish this objective, we passed whole blood and re-constituted blood samples (purified red blood cells suspended in buffer or in autologous plasma) through an artificial microvascular network (AMVN) comprising completely inert, microfabricated vessels with the architecture inspired by the real microvasculature. We found that the flow of blood in capillaries of the AMVN indeed oscillates with characteristic frequencies in the range of 0-0.6 Hz, which is in a very good agreement with previous computational studies and in vivo observations. We also found that the traffic of leukocytes through the network (typically neglected in computational modeling) plays an important role in generating the oscillations. This study represents the key piece of experimental evidence in support of the hypothesis that spontaneous, self-sustained oscillations of capillary blood flow can be generated solely by the non-linear rheological properties of blood flowing through microvascular networks, and provides an insight into the mechanism of this fundamentally important microcirculatory phenomenon.

  19. Implantable blood pressure sensor for analyzing elasticity in arteries

    Science.gov (United States)

    Franco-Ayala, Marco; Martínez-Piñón, Fernando; Reyes-Barranca, Alfredo; Sánchez de la Peña, Salvador; Álvarez-Chavez, José A.

    2009-03-01

    MEMS technology could be an option for the development of a pressure sensor which allows the monitoring of several electronic signals in humans. In this work, a comparison is made between the typical elasticity curves of several arteries in the human body and the elasticity obtained for MEMS silicon microstructures such as membranes and cantilevers employing Finite Element analysis tools. The purpose is to identify which types of microstructures are mechanically compatible with human arteries. The goal is to integrate a blood pressure sensor which can be implanted in proximity with an artery. The expected benefits for this type of sensor are mainly to reduce the problems associated with the use of bulk devices through the day and during several days. Such a sensor could give precise blood pressure readings in a continuous or periodic form, i.e. information that is especially important for some critical cases of hypertension patients.

  20. Nocturnal foot blood flow in patients with arterial insufficiency

    DEFF Research Database (Denmark)

    Jelnes, Rolf; Tønnesen, K H

    1984-01-01

    was on average the same in patients with normal circulations and in patients with different degrees of arterial insufficiency (mean: 2.0 +/- 0.8 ml min-1 100 g-1). During sleep the blood flow nearly doubled in patients with normal circulations; no systematic change was seen in patients with intermittent...

  1. ABO Blood Group and Risk of Thromboembolic and Arterial Disease

    DEFF Research Database (Denmark)

    Vasan, Senthil K; Rostgaard, Klaus; Majeed, Ammar

    2016-01-01

    BACKGROUND: ABO blood groups have been shown to be associated with increased risks of venous thromboembolic and arterial disease. However, the reported magnitude of this association is inconsistent and is based on evidence from small-scale studies. METHODS AND RESULTS: We used the SCANDAT2 (Scand...

  2. From artificial red blood cells, oxygen carriers, and oxygen therapeutics to artificial cells, nanomedicine, and beyond.

    Science.gov (United States)

    Chang, Thomas M S

    2012-06-01

    The first experimental artificial red blood cells have all three major functions of red blood cells (rbc). However, the first practical one is a simple polyhemoglobin (PolyHb) that only has an oxygen-carrying function. This is now in routine clinical use in South Africa and Russia. An oxygen carrier with antioxidant functions, PolyHb-catalase-superoxide dismutase, can fulfill two of the three functions of rbc. Even more complete is one with all three functions of rbc in the form of PolyHb-catalase-superoxide dismutase-carbonic anhydrase. The most advanced ones are nanodimension artificial rbc with either PEG-lipid membrane or PEG-PLA polymer membrane. Extensions into oxygen therapeutics include a PolyHb-tyrosinase that suppresses the growth of melanoma in a mice model. Another is a PolyHb-fibrinogen that is an oxygen carrier with platelet-like function. Research has now extended well beyond the original research on artificial rbc into many areas of artificial cells. These include nanoparticles, nanotubules, lipid vesicles, liposomes, polymer-tethered lipid vesicles, polymersomes, microcapsules, bioencapsulation, nanocapules, macroencapsulation, synthetic cells, and others. These are being used in nanotechnology, nanomedicine, regenerative medicine, enzyme/gene therapy, cell/stem cell therapy, biotechnology, drug delivery, hemoperfusion, nanosensers, and even by some groups in agriculture, industry, aquatic culture, nanocomputers, and nanorobotics.

  3. Anatomy of the bovine ascending aorta and brachiocephalic artery found unfavorable for total artificial heart implant.

    Science.gov (United States)

    Karimov, Jamshid H; Sunagawa, Gengo; Such, Kimberly A; Sale, Shiva; Golding, Leonard A R; Moazami, Nader; Fukamachi, Kiyotaka

    2015-12-01

    The biocompatibility assessment of the Cleveland Clinic continuous-flow total artificial heart is an important part of the device developmental program. Surgical and postoperative management are key factors in achieving optimal outcomes. However, the presence of vascular anatomical abnormalities in experimental animal models is often unpredictable and may worsen the expected outcomes. We report a technical impediment encountered during total artificial heart implantation complicated by unfavorable bovine anatomy of the ascending aorta and brachiocephalic arterial trunk.

  4. Peripheral arterial blood pressure monitoring adequately tracks central arterial blood pressure in critically ill patients: an observational study

    OpenAIRE

    Mignini, Mariano Alejandro; Piacentini, Enrique; Dubin,Arnaldo

    2006-01-01

    Introduction Invasive arterial blood pressure monitoring is a common practice in intensive care units (ICUs). Accuracy of invasive blood pressure monitoring is crucial in evaluating the cardiocirculatory system and adjusting drug therapy for hemodynamic support. However, the best site for catheter insertion is controversial. Lack of definitive information in critically ill patients makes it difficult to establish guidelines for daily practice in intensive care. We hypothesize that peripheral ...

  5. AN ANALYSIS MODEL OF PULSATILE BLOOD FLOW IN ARTERIES

    Institute of Scientific and Technical Information of China (English)

    LIUZhao-rong; XUGang; CHENYong; TENGZhong0=zhao; QINKai-rong

    2003-01-01

    Blood flow in artery was treated as the flow under equilibriums state(the steady flow under mean pressure)combined with the periodically small pulsatile flow.Using vascular strain energy function advanced by Fung,the vascular stress-strain relationship under equilibrium state was analyzed and the circumferential and axial elastic moduli were deduced that are expressed while the arterial strains around the equilibrium state are relatively small,so that the equations of vesse wall motion under the pulsatile pressure could be established here.Through solving both the vessel equations and the linear Navier-Stokes equations,the analytic expressions of the blood flow velocities and the vascular displacements were obtained.The influence of the difference between vascular circumferentia and axial elasticities on pulsatile blood flow and vascular motion was discussed in details.

  6. AN ANALYSIS MODEL OF PULSATILE BLOOD FLOW IN ARTERIES

    Institute of Scientific and Technical Information of China (English)

    柳兆荣; 徐刚; 陈泳; 滕忠照; 覃开蓉

    2003-01-01

    Blood flow in artery was treated as the flow under equilibrium state ( the steady flow under mean pressure ) combined with the periodically small pulsatile flow. Using vascular strain energy function advanced by Fung, the vascular stress-strain relationship under equilibrium state was analyzed and the circumferential and axial elastic moduli were deduced that are expressed while the arterial strains around the equilibrium state are relatively small, so that the equations of vessel wall motion under the pulsatile pressure could be established here. Through solving both the vessel equations and the linear NavierStokes equations, the analytic expressions of the blood flow velocities and the vascular displacements were obtained. The influence of the difference between vascular circumferential and axial elasticities on pulsatile blood flow and vascular motion was discussed in details.

  7. Noninvasive 24-hour ambulatory arterial blood pressure monitoring in cirrhosis

    DEFF Research Database (Denmark)

    Møller, Søren; Wiinberg, N; Henriksen, Jens Henrik

    1995-01-01

    were almost similar in the two groups (108 vs. 110; 65 vs. 67; 78 vs. 82 mm Hg, NS). Conversely, HR was significantly higher in the patients both in the daytime (86 vs. 72/min, P pressure and HR from daytime......Cirrhotic patients have disturbed systemic hemodynamics with reduced arterial blood pressure, but this has not been investigated during daily activity and sleep. Systolic (SBP), diastolic (DBP), and mean arterial blood pressure (MAP), and heart rate (HR) were measured by an automatic ambulant...... device for monitoring blood pressure in 35 patients with cirrhosis and 35 healthy matched controls. During the daytime, SBP, DBP, and MAP were significantly lower in the patients than in the controls (median 118 vs. 127; 70 vs. 78; 86 vs. 94 mm Hg, P pressures...

  8. Parameters of Blood Flow in Great Arteries in Hypertensive ISIAH Rats with Stress-Dependent Arterial Hypertension.

    Science.gov (United States)

    Seryapina, A A; Shevelev, O B; Moshkin, M P; Markel', A L

    2016-08-01

    Magnetic resonance angiography was used to examine blood flow in great arteries of hypertensive ISIAH and normotensive Wistar rats. In hypertensive ISIAH rats, increased vascular resistance in the basin of the abdominal aorta and renal arteries as well as reduced fraction of total renal blood flow were found. In contrast, blood flow through both carotid arteries in ISIAH rats was enhanced, which in suggests more intensive blood supply to brain regulatory centers providing enhanced stress reactivity of these rats characterized by stress-dependent arterial hypertension.

  9. Effects of non Newtonian spiral blood flow through arterial stenosis

    Science.gov (United States)

    Hasan, Md. Mahmudul; Maruf, Mahbub Alam; Ali, Mohammad

    2016-07-01

    The spiral component of blood flow has both beneficial and detrimental effects in human circulatory system. A numerical investigation is carried out to analyze the effect of spiral blood flow through an axisymmetric three dimensional artery having 75% stenosis at the center. Blood is assumed as a Non-Newtonian fluid. Standard k-ω model is used for the simulation with the Reynolds number of 1000. A parabolic velocity profile with spiral flow is used as inlet boundary condition. The peak values of all velocity components are found just after stenosis. But total pressure gradually decreases at downstream. Spiral flow of blood has significant effects on tangential component of velocity. However, the effect is mild for radial and axial velocity components. The peak value of wall shear stress is at the stenosis zone and decreases rapidly in downstream. The effect of spiral flow is significant for turbulent kinetic energy. Detailed investigation and relevant pathological issues are delineated throughout the paper.

  10. Investigation on artificial blood vessels prepared from bacterial cellulose

    Energy Technology Data Exchange (ETDEWEB)

    Zang, Shanshan; Zhang, Ran; Chen, Hua; Lu, Yudong; Zhou, Jianhai [Department of Biomedical Engineering, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074 (China); Chang, Xiao; Qiu, Guixing; Wu, Zhihong [Department of Orthopaedics, Peking Union Medical College Hospital, Beijing 100730 (China); Yang, Guang, E-mail: yang_sunny@yahoo.com [Department of Biomedical Engineering, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074 (China)

    2015-01-01

    BC (bacterial cellulose) exhibits quite distinctive properties than plant cellulose. The outstanding properties make BC a promising material for preparation of artificial blood vessel. By taking advantage of the high oxygen permeability of PDMS (polydimethylsiloxane) as a tubular template material, a series of BC tubes with a length of 100 mm, a thickness of 1 mm and an outer diameter of 4 or 6 mm were biosynthesized with the help of Gluconacetobacter xylinum. Through characterization by SEM (scanning electron microscope), tensile testing and thermal analysis, it is demonstrated that BC tubes are good enough for artificial blood vessel with elaborated nano-fiber architecture, qualified mechanical properties and high thermal stability. In addition, measurement of biocompatibility also shows that BC tubes are greatly adaptable to the in vivo environment. The results indicate that BC tubes have great potential for being utilized as tubular scaffold materials in the field of tissue engineering. - Highlights: • Bacterial cellulose (BC) can be made into tubular shape through PDMS mold. • BC represents a fine nanofiber network. • The mechanical and thermal properties of BC mimic the situation of real vessel. • BC exhibits attractive biocompatible properties as a substitution of vessel.

  11. Accurate blood flow measurements: are artificial tracers necessary?

    Directory of Open Access Journals (Sweden)

    Christian Poelma

    Full Text Available Imaging-based blood flow measurement techniques, such as particle image velocimetry, have become an important tool in cardiovascular research. They provide quantitative information about blood flow, which benefits applications ranging from developmental biology to tumor perfusion studies. Studies using these methods can be classified based on whether they use artificial tracers or red blood cells to visualize the fluid motion. We here present the first direct comparison in vivo of both methods. For high magnification cases, the experiments using red blood cells strongly underestimate the flow (up to 50% in the present case, as compared to the tracer results. For medium magnification cases, the results from both methods are indistinguishable as they give the same underestimation of the real velocities (approximately 33%, based on in vitro reference measurements. These results suggest that flow characteristics reported in literature cannot be compared without a careful evaluation of the imaging characteristics. A method to predict the expected flow averaging behavior for a particular facility is presented.

  12. Accurate blood flow measurements: are artificial tracers necessary?

    Science.gov (United States)

    Poelma, Christian; Kloosterman, Astrid; Hierck, Beerend P; Westerweel, Jerry

    2012-01-01

    Imaging-based blood flow measurement techniques, such as particle image velocimetry, have become an important tool in cardiovascular research. They provide quantitative information about blood flow, which benefits applications ranging from developmental biology to tumor perfusion studies. Studies using these methods can be classified based on whether they use artificial tracers or red blood cells to visualize the fluid motion. We here present the first direct comparison in vivo of both methods. For high magnification cases, the experiments using red blood cells strongly underestimate the flow (up to 50% in the present case), as compared to the tracer results. For medium magnification cases, the results from both methods are indistinguishable as they give the same underestimation of the real velocities (approximately 33%, based on in vitro reference measurements). These results suggest that flow characteristics reported in literature cannot be compared without a careful evaluation of the imaging characteristics. A method to predict the expected flow averaging behavior for a particular facility is presented.

  13. Arterial blood oxygen saturation during blood pressure cuff-induced hypoperfusion

    Science.gov (United States)

    Kyriacou, P. A.; Shafqat, K.; Pal, S. K.

    2007-10-01

    Pulse oximetry has been one of the most significant technological advances in clinical monitoring in the last two decades. Pulse oximetry is a non-invasive photometric technique that provides information about the arterial blood oxygen saturation (SpO2) and heart rate, and has widespread clinical applications. When peripheral perfusion is poor, as in states of hypovolaemia, hypothermia and vasoconstriction, oxygenation readings become unreliable or cease. The problem arises because conventional pulse oximetry sensors must be attached to the most peripheral parts of the body, such as finger, ear or toe, where pulsatile flow is most easily compromised. Pulse oximeters estimate arterial oxygen saturation by shining light at two different wavelengths, red and infrared, through vascular tissue. In this method the ac pulsatile photoplethysmographic (PPG) signal associated with cardiac contraction is assumed to be attributable solely to the arterial blood component. The amplitudes of the red and infrared ac PPG signals are sensitive to changes in arterial oxygen saturation because of differences in the light absorption of oxygenated and deoxygenated haemoglobin at these two wavelengths. From the ratios of these amplitudes, and the corresponding dc photoplethysmographic components, arterial blood oxygen saturation (SpO2) is estimated. Hence, the technique of pulse oximetry relies on the presence of adequate peripheral arterial pulsations, which are detected as photoplethysmographic (PPG) signals. The aim of this study was to investigate the effect of pressure cuff-induced hypoperfusion on photoplethysmographic signals and arterial blood oxygen saturation using a custom made finger blood oxygen saturation PPG/SpO2 sensor and a commercial finger pulse oximeter. Blood oxygen saturation values from the custom oxygen saturation sensor and a commercial finger oxygen saturation sensor were recorded from 14 healthy volunteers at various induced brachial pressures. Both pulse

  14. Arterial blood oxygen saturation during blood pressure cuff-induced hypoperfusion

    Energy Technology Data Exchange (ETDEWEB)

    Kyriacou, P A [School of Engineering and Mathematical Sciences, City University, London EC1V 0HB (United Kingdom); Shafqat, K [School of Engineering and Mathematical Sciences, City University, London EC1V 0HB (United Kingdom); Pal, S K [St Andrew' s Centre for Plastic Surgery and Burns, Broomfield Hospital, Chelmsford, CM1 7ET (United Kingdom)

    2007-10-15

    Pulse oximetry has been one of the most significant technological advances in clinical monitoring in the last two decades. Pulse oximetry is a non-invasive photometric technique that provides information about the arterial blood oxygen saturation (SpO{sub 2}) and heart rate, and has widespread clinical applications. When peripheral perfusion is poor, as in states of hypovolaemia, hypothermia and vasoconstriction, oxygenation readings become unreliable or cease. The problem arises because conventional pulse oximetry sensors must be attached to the most peripheral parts of the body, such as finger, ear or toe, where pulsatile flow is most easily compromised. Pulse oximeters estimate arterial oxygen saturation by shining light at two different wavelengths, red and infrared, through vascular tissue. In this method the ac pulsatile photoplethysmographic (PPG) signal associated with cardiac contraction is assumed to be attributable solely to the arterial blood component. The amplitudes of the red and infrared ac PPG signals are sensitive to changes in arterial oxygen saturation because of differences in the light absorption of oxygenated and deoxygenated haemoglobin at these two wavelengths. From the ratios of these amplitudes, and the corresponding dc photoplethysmographic components, arterial blood oxygen saturation (SpO{sub 2}) is estimated. Hence, the technique of pulse oximetry relies on the presence of adequate peripheral arterial pulsations, which are detected as photoplethysmographic (PPG) signals. The aim of this study was to investigate the effect of pressure cuff-induced hypoperfusion on photoplethysmographic signals and arterial blood oxygen saturation using a custom made finger blood oxygen saturation PPG/SpO{sub 2} sensor and a commercial finger pulse oximeter. Blood oxygen saturation values from the custom oxygen saturation sensor and a commercial finger oxygen saturation sensor were recorded from 14 healthy volunteers at various induced brachial pressures

  15. PREDICTION OF BLOOD PATTERN IN S-SHAPED MODEL OF ARTERY UNDER NORMAL BLOOD PRESSURE

    Directory of Open Access Journals (Sweden)

    Mohd Azrul Hisham Mohd Adib

    2013-06-01

    Full Text Available Athletes are susceptible to a wide variety of traumatic and non-traumatic vascular injuries to the lower limb. This paper aims to predict the three-dimensional flow pattern of blood through an S-shaped geometrical artery model. This model has created by using Fluid Structure Interaction (FSI software. The modeling of the geometrical S-shaped artery is suitable for understanding the pattern of blood flow under constant normal blood pressure. In this study, a numerical method is used that works on the assumption that the blood is incompressible and Newtonian; thus, a laminar type of flow can be considered. The authors have compared the results with a previous study with FSI validation simulation. The validation and verification of the simulation studies is performed by comparing the maximum velocity at t = 0.4 s, because at this time, the blood accelerates rapidly. In addition, the resulting blood flow at various times, under the same boundary conditions in the S-shaped geometrical artery model, is presented. The graph shows that velocity increases linearly with time. Thus, it can be concluded that the flow of blood increases with respect to the pressure inside the body.

  16. Polymer/hemoglobin assemblies: biodegradable oxygen carriers for artificial red blood cells.

    Science.gov (United States)

    Li, Taihang; Jing, Xiabin; Huang, Yubin

    2011-07-07

    In routine clinical procedures, blood transfusion is now suffering from the defects of the blood products, like cross-matching, short storage time and virus infection. Various blood substitutes have been designed by researchers through continual efforts. With recent progress in nanotechnology, new types of artificial red blood cells with cellular structure are available. This article aims to describe some artificial red blood cells which encapsulate or conjugate hemoglobin molecules through various approaches, especially the nanoscale self-assembly technique, to mitigate the adverse effects of free hemoglobin molecules. These types of artificial red blood cell systems, which make use of biodegradable polymers as matrix materials, show advantages over the traditional types.

  17. An artificial blood vessel implanted three-dimensional microsystem for modeling transvascular migration of tumor cells.

    Science.gov (United States)

    Wang, Xue-Ying; Pei, Ying; Xie, Min; Jin, Zi-He; Xiao, Ya-Shi; Wang, Yang; Zhang, Li-Na; Li, Yan; Huang, Wei-Hua

    2015-02-21

    Reproducing a tumor microenvironment consisting of blood vessels and tumor cells for modeling tumor invasion in vitro is particularly challenging. Here, we report an artificial blood vessel implanted 3D microfluidic system for reproducing transvascular migration of tumor cells. The transparent, porous and elastic artificial blood vessels are obtained by constructing polysaccharide cellulose-based microtubes using a chitosan sacrificial template, and possess excellent cytocompatibility, permeability, and mechanical characteristics. The artificial blood vessels are then fully implanted into the collagen matrix to reconstruct the 3D microsystem for modeling transvascular migration of tumor cells. Well-defined simulated vascular lumens were obtained by proliferation of the human umbilical vein endothelial cells (HUVECs) lining the artificial blood vessels, which enables us to reproduce structures and functions of blood vessels and replicate various hemodynamic parameters. Based on this model, the adhesion and transvascular migration of tumor cells across the artificial blood vessel have been well reproduced.

  18. Tasting Arterial Blood: What do the Carotid Chemoreceptors Sense?

    Directory of Open Access Journals (Sweden)

    Nanduri R. Prabakhar

    2015-01-01

    Full Text Available The carotid bodies are sensory organs that detect the chemical composition of the arterial blood. The carotid body sensory activity increases in response to arterial hypoxemia and the ensuing chemoreflex regulates vital homeostatic functions. Recent studies suggest that the carotid bodies might also sense arterial blood glucose and circulating insulin levels. This review focuses on how the carotid bodies sense O2, glucose and insulin and some potential implications of these sensory functions on physiological regulation and in pathophysiological conditions. Emerging evidence suggests that carbon monoxide (CO-regulated hydrogen sulfide (H2S, stemming from hypoxia, depolarizes type I cells by inhibiting certain K+ channels, facilitates voltage-gated Ca2+ influx leading to sensory excitation of the carotid body. Elevated CO and decreased H2S renders the carotid bodies insensitive to hypoxia resulting in attenuated ventilatory adaptations to high altitude hypoxia, whereas reduced CO and high H2S result in hypersensitivity of the carotid bodies to hypoxia and hypertension. Acute hypoglycemia augments the carotid body responses to hypoxia but that a prolonged lack of glucose in the carotid bodies can lead to a failure to sense hypoxia. Emerging evidence also indicates that carotid bodies might sense insulin directly independent of its effect on glucose, linking the carotid bodies to the pathophysiological consequences of the metabolic syndrome. How glucose and insulin interact with the CO-H2S signalling is an area of ongoing study.KEY WORDS: Glomus cells, K+ channels, Carbon monoxide, hydrogen sulfide, hypoglycemia, diabetes.

  19. Dopexamine increases internal mammary artery blood flow following coronary artery bypass grafting.

    LENUS (Irish Health Repository)

    Flynn, Michael J

    2012-02-03

    OBJECTIVE: Vasoactive agents and inotropes influence conduit-coronary blood flow following coronary artery bypass grafting (CABG). It was hypothesized that dopexamine hydrochloride, a dopamine A-1 (DA-1) and beta(2) agonist would increase conduit-coronary blood flow. A prospective randomized double blind clinical trial was carried out to test this hypothesis. DA-1 receptors have previously been localized to human left ventricle. METHODS: Twenty-six American Society of Anaesthesiology class 2-3 elective coronary artery bypass graft patients who did not require inotropic support on separation from cardiopulmonary bypass (CPB) were studied. According to a randomized allocation patients received either dopexamine (1 microg\\/kg per min) or placebo (saline) by intravenous infusion for 15 min. Immediately prior to and at 5,10 and 15 min of infusion, blood flow through the internal mammary and vein grafts (Transit time flow probes, Transonic Ltd.), heart rate, cardiac index, mean arterial pressure and pulmonary haemodynamics were noted. The data were analysed using multivariate analysis of variance. RESULTS: Low-dose dopexamine (1 microg\\/kg per min) caused a significant increase in mammary graft blood flow compared to placebo at 15 min of infusion (P=0.028, dopexamine group left internal mammary artery (LIMA) flow of 43.3+\\/-14.2 ml\\/min, placebo group LIMA flow at 26.1+\\/-16.3 ml\\/min). Dopexamine recipients demonstrated a non-significant trend to increased saphenous vein graft flow (P=0.059). Increased heart rate was the only haemodynamic change induced by dopexamine (P=0.004, dopexamine group at 85.2+\\/-9.6 beats\\/min and placebo group at 71.1+\\/-7.6 beats\\/min after 15 min of infusion). CONCLUSION: This study demonstrates that administration of dopexamine (1 microg\\/kg per min) was associated with a significant increase in internal mammary artery graft blood flow with mild increase in heart rate being the only haemodynamic change. Low-dose dopexamine may

  20. Predicting Endometrium Receptivity with Parameters of Spiral Artery Blood Flow

    Institute of Scientific and Technical Information of China (English)

    GONG Xuehao; LI Quanshui; ZHANG Qingping; ZHU Guijin

    2005-01-01

    Summary: In order To evaluate whether the parameters of spiral artery blood flow, as measured by transvaginal color Doppler, may be used to assess endometrium receptivity prior to embryo transfer (ET), a retrospective study of 94 infertile women who had undergone ART treatments with different outcomes (pregnant or nonpregnant) was done. Subendometrial blood flow was evaluated. The resistance index (RI), systolic/diastolic ratio (S/D) and pulsatility index (PI) were significantly lower in those who achieved pregnancy as compared with those who did not: 0.62±0.04 vs 0.68±0.04 (P<0.001), 2.66±0.33 vs 3.19±0.39 (P<0.01) and 1.15±0.17 vs 1.34±0.22 (P<0.05), respectively. Furthermore, when RI>0.72, PI>1.6, and S/D>3.6, no pregnancy occurred. These data suggest that the parameters of spiral artery blood flow could be used as a new assay in predicting endometrial receptivity before ET.

  1. Measurement of Blood Flow in an Intracranial Artery Bypass From the Internal Maxillary Artery by Intraoperative Duplex Sonography.

    Science.gov (United States)

    Yu, Zaitao; Shi, Xiang'en; Brohi, Shams Raza; Qian, Hai; Liu, Fangjun; Yang, Yang

    2017-02-01

    This study explored the hemodynamic characteristics of a subcranial-intracranial bypass from the internal maxillary artery by measuring blood flow on intraoperative duplex sonography. The hemodynamic parameters of the internal maxillary artery (n = 20), radial artery (n = 20), internal maxillary artery-middle cerebral artery bypass (n = 42), and internal maxillary artery-posterior cerebral artery bypass (n = 9) were measured by intraoperative duplex sonography. There was no significant difference in the internal diameters of the internal maxillary and radial arteries (mean ± SD, 2.51 ± 0.34 versus 2.56 ± 0.22 mm; P = .648). The mean radial artery graft length for subcranial-intracranial bypasses was 88.5 ± 12.78 mm (95% confidence interval [CI], 80.8-90.2 mm). Internal maxillary artery-middle cerebral artery bypasses required a shorter radial artery graft than internal maxillary artery-posterior cerebral artery bypasses (77.8 ± 2.47 versus 104.8 ± 4.77 mm; P = .001). The mean flow volumes were 85.3 ± 18.5 mL/min (95% CI, 76.6-93.9 mL/min) for the internal maxillary artery, 72.6 ± 26.4 mL/min (95% CI, 64.3-80.9 mL/min) for internal maxillary artery-middle cerebral artery bypasses, and 45.4 ± 6.7 mL/min (95% CI, 40.7-50.0 mL/min) for internal maxillary artery-posterior cerebral artery bypasses. All grafts were opened after the success of the salvage procedures had been established, and the early patency rates (1 month after the operation) were 95% for internal maxillary artery-middle cerebral artery bypasses and 100% the internal maxillary artery-posterior cerebral artery bypasses. Measurement of blood flow by intraoperative sonography can be helpful in decision making and predicting graft patency and success after neurosurgical bypass procedures.

  2. Novel blood sampling method of an artificial endocrine pancreas via the cardiopulmonary bypass circuit.

    Science.gov (United States)

    Kawahito, Shinji; Higuchi, Seiichi; Mita, Naoji; Kitagawa, Tetsuya; Kitahata, Hiroshi

    2013-12-01

    We tried to perform continuous blood glucose monitoring during cardiovascular surgery involving cardiopulmonary bypass using an artificial endocrine pancreas (STG-22 or -55; Nikkiso, Tokyo, Japan); however, we often encountered problems during these procedures because insufficient blood was obtained for monitoring. Thus, we started performing the blood sampling via the venous side of the cardiopulmonary bypass circuit. As a result, continuous blood glucose monitoring using an artificial endocrine pancreas was proven to be stable and reliable during cardiovascular surgery involving cardiopulmonary bypass.

  3. Unsteady magnetohydrodynamic blood flow through irregular multi-stenosed arteries.

    Science.gov (United States)

    Mustapha, Norzieha; Amin, Norsarahaida; Chakravarty, Santabrata; Mandal, Prashanta Kumar

    2009-10-01

    Flow of an electrically conducting fluid characterizing blood through the arteries having irregular shaped multi-stenoses in the environment of a uniform transverse magnetic-field is analysed. The flow is considered to be axisymmetric with an outline of the irregular stenoses obtained from a three-dimensional casting of a mild stenosed artery, so that the physical problem becomes more realistic from the physiological point of view. The marker and cell (MAC) and successive-over-relaxation (SOR) methods are respectively used to solve the governing unsteady magnetohydrodynamic (MHD) equations and pressure-Poisson equation quantitatively and to observe the flow separation. The results obtained show that the flow separates mostly towards the downstream of the multi-stenoses. However, the flow separation region keeps on shrinking with the increasing intensity of the magnetic-field which completely disappears with sufficiently large value of the Hartmann number. The present observations certainly have some clinical implications relating to magnetotherapy which help reducing the complex flow separation zones causing flow disorder leading to the formation and progression of the arterial diseases.

  4. Intraspecific scaling of arterial blood pressure in the Burmese python.

    Science.gov (United States)

    Enok, Sanne; Slay, Christopher; Abe, Augusto S; Hicks, James W; Wang, Tobias

    2014-07-01

    Interspecific allometric analyses indicate that mean arterial blood pressure (MAP) increases with body mass of snakes and mammals. In snakes, MAP increases in proportion to the increased distance between the heart and the head, when the heart-head vertical distance is expressed as ρgh (where ρ is the density of blood, G: is acceleration due to gravity and h is the vertical distance above the heart), and the rise in MAP is associated with a larger heart to normalize wall stress in the ventricular wall. Based on measurements of MAP in Burmese pythons ranging from 0.9 to 3.7 m in length (0.20-27 kg), we demonstrate that although MAP increases with body mass, the rise in MAP is merely half of that predicted by heart-head distance. Scaling relationships within individual species, therefore, may not be accurately predicted by existing interspecific analyses.

  5. [Analysis of the timing parameters of blood flow in the carotid basin arteries of hypertensive patients].

    Science.gov (United States)

    Makarenko, E S

    2011-01-01

    Vascular duplex ultrasound study with simultaneous ECG recording was performed to estimate the timing parameters of blood flow in the common carotid, internal carotid, and middle cerebral arteries in patients with grades 1 and 2 arterial hypertension. There was an increase in the blood flow acceleration phase index in the common carotid and middle cerebral arteries and a reduction in the systolic phase index in the internal carotid arteries. There were correlations of phasic blood flow parameters in the extra- and intracranial arteries with age and lipidogram readings.

  6. Relationship of daily arterial blood pressure monitoring readings and arterial stiffness profile in male patients with chronic obstructive pulmonary disease combined with arterial hypertension

    Directory of Open Access Journals (Sweden)

    Karoli N.A.

    2013-06-01

    Full Text Available The aim of the study was to determine correlation between arterial blood pressure daily rhythm and daily profile of arterial stiffness in male patients with chronic obstructive pulmonary disease (COPD and arterial hypertension. Materials et methods: Prospective investigation comprised 45 male patients with COPD and arterial hypertension. Individuals of 40 years younger and 80 years elder, patients with diabetes, stroke, angina pectoris, or heart infarction, vascular diseases, and exacerbation of chronic disease, bronchial and pulmonary diseases of other etiology were excluded from the analyses. Comparison group included 47 patients with essential arterial hypertension and without chronic respiratory diseases closely similar on general parameters with patients from main clinical series. Twenty-four-hour arterial blood pressure monitoring (ABPM and daily arterial stiffness monitoring were performed using BPLab® MnSDP-2 apparatus (Petr Telegin, Russian Federation. Results: Patients with COPD combined with arterial hypertension with raised arterial stiffness measures prevail over individuals in essential hypertension group. There is pathological alteration of the ABPM circadian rhythm and raised «Pressure load» values in raised arterial stiffness group. Conclusion: We found ABPM raised parameters in patients with COPD and arterial hypertension. It confirms necessity of ABPM in daily arterial stiffness assessment in patients with COPD.

  7. Enzymatic method for determining ketone body ratio in arterial blood.

    Science.gov (United States)

    Uno, S; Takehiro, O; Tabata, R; Ozawa, K

    1995-12-01

    We have developed a new, sensitive, and rapid method for measuring the ketone body concentration in arterial blood and determining the arterial blood ketone body ratio. The procedure involves the sequential use of the enzymes 3-hydroxybutyrate dehydrogenase (3-HBDH; EC 1.1.1.30) and NADH oxidase, followed by a color-generating reaction with the hydrogen peroxide produced by the oxidase reaction. The amount of oxidized chromogen produced is proportional to the 3-hydroxybutyrate (3-HBA) concentration. The acetoacetate (AcAc) concentration is obtained after complete conversion of the AcAc to 3-HBA, in the presence of 3-HBDH. The total 3-HBA concentration is measured and then subtracted from the total ketone body concentration to give the AcAc concentration. This procedure may be applied to plasma samples and the absorbance change measured with an automated chemistry analyzer. Ketone body concentration may be determined over the range 0 to 400 mumol/L. The analysis takes approximately 12 min and requires only 30 microL of plasma.

  8. MR-based coronary artery blood velocity measurements in patients without coronary artery disease

    Energy Technology Data Exchange (ETDEWEB)

    Schiemann, M.; Esmaeili, A.; Vogl, T.J. [Johann Wolfgang Goethe-University, Institute of Diagnostic and Interventional Radiology University Hospital, Frankfurt am Main (Germany); Bakhtiary, F.; Moritz, A. [University HospitalJohann Wolfgang Goethe-University, Department of Thoracic and Cardiovascular Surgery, Frankfurt am Main (Germany); Hietschold, V. [University Hospital Carl Gustav Carus Technical University Dresden, Institute of Diagnostic Radiology, Dresden (Germany); Koch, A.; Abolmaali, N.D. [Johann Wolfgang Goethe-University, Institute of Diagnostic and Interventional Radiology University Hospital, Frankfurt am Main (Germany); University Hospital Carl Gustav Carus Techinical University Dresden, ZIK OncoRay - Molecular Imaging, Dresden (Germany); Ackermann, H. [Johann Wolfgang Goethe University, Department for Biomathematics, Frankfurt am Main (Germany)

    2006-05-15

    To evaluate the feasibility of MR-based coronary blood velocity measurements (MRvenc) in patients without coronary artery disease (CAD). Eighty-three patients with angiographically excluded CAD received MRvenc of the proximal segments of both coronary arteries (CAs). Using a retrospectively ECG-gated breath-hold phase-contrast FLASH sequence with high temporal resolution, flow data were technically acquirable in 137/166 (83%) CAs. Quantification and analysis of blood velocities in systole and diastole of both CAs were performed. Biphasic velocity profiles were found in 83/100 CAs. Median systolic and diastolic velocities differed significantly in LCA (19 cm/s, 24 cm/s; P<0.0001) and RCAs (14 cm/s, 16 cm/s; P<0.01). The diastolic/systolic velocity ratio was calculated in LCAs and RCAs with a median of 1.3 and 1.1, respectively. The velocity profiles of the remaining CAs were monophasic (17 CAs) or revealed severe alterations of the physiologic velocity profile with reduced flow undulations and steady velocities (37 CAs). Optimized clinical MRvenc is feasible to quantify blood velocities in the CAs. Potential indications are (1) non-invasive monitoring of patients after aortic valve reconstruction as well as (2) detection of asymptomatic CAD patients. (orig.)

  9. A comparison of blood gases and acid-base measurements in arterial, arterialized venous, and venous blood during short-term maximal exercise.

    Science.gov (United States)

    Linderman, J; Fahey, T D; Lauten, G; Brooker, A S; Bird, D; Dolinar, B; Musselman, J; Lewis, S; Kirk, L

    1990-01-01

    The purpose of this study was to determine the relationship between blood gases and acid-base measurements in arterial, arterialized venous, and venous blood measured simultaneously during short-term maximal exercise. Ten well-trained male cyclists performed a graded maximal exercise test on a cycle ergometer to determine the power output corresponding to their peak oxygen consumption (test I), and a short-term maximal test on a cycle ergometer at peak power output (test II). During test II arterial, arterialized venous and venous blood were sampled simultaneously for determination of partial pressures of oxygen and carbon dioxide, pH, bicarbonate (HCO3-), base excess (BE), and lactate (La). Samples were taken at rest, the end of 1 min of exercise (1 ME), at the end of exercise (EE), and at 2 min of recovery (REC). During test II, subjects maintained a peak power output of 370.6 (62.1) W [mean (SD)] for 4.5, SD 1.6 min. Except at rest venous and arterialized venous measurements tended to be the same at all sampling intervals, but differed significantly from measurements in arterial blood (P less than 0.05). BE was the only variable that rendered consistently significant correlations between arterial and arterialized venous blood at each sampling interval. The pooled correlation coefficient between arterial and arterialized venous BE was r = 0.83 [regression equation: BEa = (0.84 BEav)-0.51]. Arterial La was significantly higher than venous La at 1 ME (2.8, 0.7 vs 0.8, 0.3 mmol.l-1) and higher than both venous and arterialized venous La at EE.(ABSTRACT TRUNCATED AT 250 WORDS)

  10. A model of blood flow in the mesenteric arterial system

    Directory of Open Access Journals (Sweden)

    Cheng Leo K

    2007-05-01

    Full Text Available Abstract Background There are some early clinical indicators of cardiac ischemia, most notably a change in a person's electrocardiogram. Less well understood, but potentially just as dangerous, is ischemia that develops in the gastrointestinal system. Such ischemia is difficult to diagnose without angiography (an invasive and time-consuming procedure mainly due to the highly unspecific nature of the disease. Understanding how perfusion is affected during ischemic conditions can be a useful clinical tool which can help clinicians during the diagnosis process. As a first step towards this final goal, a computational model of the gastrointestinal system has been developed and used to simulate realistic blood flow during normal conditions. Methods An anatomically and biophysically based model of the major mesenteric arteries has been developed to be used to simulate normal blood flows. The computational mesh used for the simulations has been generated using data from the Visible Human project. The 3D Navier-Stokes equations that govern flow within this mesh have been simplified to an efficient 1D scheme. This scheme, together with a constitutive pressure-radius relationship, has been solved numerically for pressure, vessel radius and velocity for the entire mesenteric arterial network. Results The computational model developed shows close agreement with physiologically realistic geometries other researchers have recorded in vivo. Using this model as a framework, results were analyzed for the four distinct phases of the cardiac cycle – diastole, isovolumic contraction, ejection and isovolumic relaxation. Profiles showing the temporally varying pressure and velocity for a periodic input varying between 10.2 kPa (77 mmHg and 14.6 kPa (110 mmHg at the abdominal aorta are presented. An analytical solution has been developed to model blood flow in tapering vessels and when compared with the numerical solution, showed excellent agreement. Conclusion An

  11. Effect of Different Blood Cycle Modes on Mass Transfer of Artificial Kidney

    Institute of Scientific and Technical Information of China (English)

    LIU Tao; He Li-qun; DING Wei-ping; Zhao Gang; GAO Da-yong

    2005-01-01

    Based on the one-dimensional and unsteady-state Krogh model, this paper investigates mass transfer of artificial kidney under three blood cycle modes during the course of hemodialysis. The variations of the permeable solute clearance with increasing time and the dialysis time with increasing blood flux are simulated in detail ,and then one optimal blood cycle mode is acquired. The results are very important to improve the clinical dialysis efficiency of artificial kidney.

  12. Blood vessel classification into arteries and veins in retinal images

    Science.gov (United States)

    Kondermann, Claudia; Kondermann, Daniel; Yan, Michelle

    2007-03-01

    The prevalence of diabetes is expected to increase dramatically in coming years; already today it accounts for a major proportion of the health care budget in many countries. Diabetic Retinopathy (DR), a micro vascular complication very often seen in diabetes patients, is the most common cause of visual loss in working age population of developed countries today. Since the possibility of slowing or even stopping the progress of this disease depends on the early detection of DR, an automatic analysis of fundus images would be of great help to the ophthalmologist due to the small size of the symptoms and the large number of patients. An important symptom for DR are abnormally wide veins leading to an unusually low ratio of the average diameter of arteries to veins (AVR). There are also other diseases like high blood pressure or diseases of the pancreas with one symptom being an abnormal AVR value. To determine it, a classification of vessels as arteries or veins is indispensable. As to our knowledge despite the importance there have only been two approaches to vessel classification yet. Therefore we propose an improved method. We compare two feature extraction methods and two classification methods based on support vector machines and neural networks. Given a hand-segmentation of vessels our approach achieves 95.32% correctly classified vessel pixels. This value decreases by 10% on average, if the result of a segmentation algorithm is used as basis for the classification.

  13. Effect of Hematocrit on Wall Shear Stress for Blood Flow through Tapered Artery

    OpenAIRE

    Singh, A. K.; Singh, D. P.

    2013-01-01

    The purpose of this study to show the effects of Hematocrit (Red blood cells), height of stenosis, porous parameter and velocity of blood on wall shear stress of the flow of blood through tapered artery. The study reveals that wall shear stress reduces for increasing Hematocrit percentage. It is also observed that wall shear stress increases as stenosis height and porous parameter increase whereas it decreases with the increasing values of velocity of blood and slope of tapered artery.

  14. Relationship between leptin levels in maternal blood,amniotic fluid,arterial and venous cord blood and fetal growth

    Institute of Scientific and Technical Information of China (English)

    林丽莎; 薛昭卿; 宋岩峰; 何晓宇

    2003-01-01

    Objective:To study the relationship between leptin concentration and fetal growth.Methods: Levels of leptin in maternal serum, amniotic fluid, arterial and venouscord blood of 65 normal parturients (gestational age 37-42weeks) were measured by ra-dioimmunoassay (RIA) method. At the same time, maternal blood lipids were detected.Neonates were divided into three groups: small for gestational age (SGA) group (n=10), appropriate for gestational age (AGA) group (n=45), large for gestational age(LGA) group (n= 10). Statistical analysis was performed by t test, variance analysisand correlation analysis.Results: (1) There was no obvious correlation between leptin concentrations in ma-ternal serum and arterial/ venous cord blood, amniotic fluid, and also no correlationwith birth weight and placental weight (P>0.05). Maternal body mass index signifi-cantly correlated with birth weight and neonatal length and leptin levels in arterial andvenous cord blood (P<0.01). Leptin levels in arterial and venous cord blood positivelycorrelated significantly with placental and neonatal weight and body length (P<0.01)and negatively correlated with high density lipoprotein (P<0. 01). There was no obvi-ous correlation between fetal gender and leptin concentrations in maternal serum, arteri-al and venous cord blood and amniotic fluid; (2) Leptin levels in arterial and venouscord blood , placental weight in LGA group were significantly higher than those in SGAand AGA group (P<0.05). Among three groups, leptin concentrations in maternalblood were significantly higher than those in arterial and venous cord blood (P<0.05).Conclusions: (1)Fetal leptin is synthesized in uterus, born of itself and placenta.Leptin levels in arterial and venous cord blood are related to the intrauterine growthpattern. It might positively regulate birth weight and body fat content. (2)Either mater-nal or fetal leptin was not correlated with fetal gender. There is no gender difference infetal leptin

  15. [Morphological characteristics and intracellular electrolytic composition of blood cells at surgeries on lower extremities arteries].

    Science.gov (United States)

    Katel'nitskiĭ, I I; Dudarev, I V; Matsionis, A E; Povilaĭtite, P E; Kvitko, I A

    2007-01-01

    Morphological characteristics and trace and macroelement composition of blood cells flowing out of ischemic lower limb before, during and after reconstructive surgeries under different type of anesthesia. A total of 102 male patients aged 45 to 60 years with atherosclerotic occlusions of the arteries of the femoral-popliteal zone were included into the study. According to anesthesia type all the patients were divided into 3 groups: group 1 consisted of 34 patients operated under spinal anesthesia, 37 patients of group 2 underwent surgery under combined anesthesia (spinal anesthesia with intravenous sedation), 31 patients of group 3 - under total intravenous anesthesia with myoplegia and artificial pulmonary ventilation. All the blood examinations were carried out with scanning electron microscope XL-30 ("Philips") and X-ray spectrum microanalyzer Edax ( "Edax International", USA). It is demonstrated that in spinal and combined anesthesia morphological characteristics of blood cells normalized due to optimization of intraerythrocytic and intrathrombocytic electrolytic homeostasis unlike total intravenous anesthesia, when intracellular imbalance of trace and macroelements progresses and ultrastructural cellular alterations persist.

  16. Arterial blood-pressure change and endogenous circulating substance P in man

    DEFF Research Database (Denmark)

    Henriksen, J H; Kastrup, J; Schaffalitzky De Muckadell, O B

    1985-01-01

    Substance P (SP) is a powerful vasodilator and this peptide is today considered to be a chemical messenger. The potential effects on circulating SP of acute changes in arterial blood-pressure was investigated in nine subjects. An increase in arterial mean blood-pressure (+33%, P less than 0.001, ...

  17. Signal quality quantification and waveform reconstruction of arterial blood pressure recordings.

    Science.gov (United States)

    Fanelli, A; Heldt, T

    2014-01-01

    Arterial blood pressure (ABP) is an important vital sign of the cardiovascular system. As with other physiological signals, its measurement can be corrupted by different sources of noise, interference, and artifact. Here, we present an algorithm for the quantification of signal quality and for the reconstruction of the ABP waveform in noise-corrupted segments of the measurement. The algorithm quantifies the quality of the ABP signal on a beat-by-beat basis by computing the normalized mean of successive differences of the ABP amplitude over each beat. In segments of poor signal quality, the ABP wavelets are then reconstructed on the basis of the expected cycle duration and envelope information derived from neighboring ABP wavelet segments. The algorithm was tested on two datasets of ABP waveform signals containing both invasive radial artery ABP and noninvasive ABP waveforms. Our results show that the approach is efficient in identifying the noisy segments (accuracy, sensitivity and specificity over 95%) and reliable in reconstructing beats that were artificially corrupted.

  18. Middle cerebral artery blood velocity and cerebral blood flow and O2 uptake during dynamic exercise

    DEFF Research Database (Denmark)

    Madsen, P L; Sperling, B K; Warming, T

    1993-01-01

    Results obtained by the 133Xe clearance method with external detectors and by transcranial Doppler sonography (TCD) suggest that dynamic exercise causes an increase of global average cerebral blood flow (CBF). These data are contradicted by earlier data obtained during less-well-defined conditions....... To investigate this controversy, we applied the Kety-Schmidt technique to measure the global average levels of CBF and cerebral metabolic rate of oxygen (CMRO2) during rest and dynamic exercise. Simultaneously with the determination of CBF and CMRO2, we used TCD to determine mean maximal flow velocity...... in the middle cerebral artery (MCA Vmean). For values of CBF and MCA Vmean a correction for an observed small drop in arterial PCO2 was carried out. Baseline values for global CBF and CMRO2 were 50.7 and 3.63 ml.100 g-1.min-1, respectively. The same values were found during dynamic exercise, whereas a 22% (P

  19. Blood feeding of Ornithodoros turicata larvae using an artificial membrane system

    Science.gov (United States)

    An artificial membrane system was adapted to feed Ornithodoros turicata larvae from a laboratory colony using defibrinated swine blood. Aspects related to larval feeding and molting to the 1st nymphal instar were evaluated. Fifty-five percent of all larvae exposed to the artificial membrane in two e...

  20. Analysis of Arterial and Venous Blood Gases in Healthy Gyr Falcons ( Falco rusticolus ) Under Anesthesia.

    Science.gov (United States)

    Raghav, Raj; Middleton, Rachael; BSc, Rinshiya Ahamed; Arjunan, Raji; Caliendo, Valentina

    2015-12-01

    Arterial and venous blood gas analysis is useful in the assessment of tissue oxygenation and ventilation and in diagnosis of metabolic and respiratory derangements. It can be performed with a relatively small volume of blood in avian patients under emergency situations. Arterial and venous blood gas analysis was performed in 30 healthy gyr falcons ( Falco rusticolus ) under anaesthesia to establish temperature-corrected reference intervals for arterial blood gas values and to compare them to temperature-corrected venous blood gas values with a portable point-of-care blood gas analyzer (i-STAT 1, Abbott Laboratories, Abbott Park, IL, USA). Statistically significant differences were observed between the temperature-corrected values of pH, partial pressure of carbon dioxide (Pco2), and partial pressure of oxygen (Po2) and the corresponding nontemperature-corrected values of these parameters in both arterial and venous blood. Values of temperature-corrected pH, temperature-corrected Pco2, bicarbonate concentrations, and base excess of extra cellular fluid did not differ significantly between arterial and venous blood, suggesting that, in anesthetized gyr falcons, venous blood gas analysis can be used in place of arterial blood gas analysis in clinical situations. Values for hematocrit, measured by the point-of-care analyzer, were significantly lower compared with those obtained by the microhematocrit method.

  1. Mathematical analysis of non-Newtonian blood flow in stenosis narrow arteries.

    Science.gov (United States)

    Sriyab, Somchai

    2014-01-01

    The flow of blood in narrow arteries with bell-shaped mild stenosis is investigated that treats blood as non-Newtonian fluid by using the K-L model. When skin friction and resistance of blood flow are normalized with respect to non-Newtonian blood in normal artery, the results present the effect of stenosis length. When skin friction and resistance of blood flow are normalized with respect to Newtonian blood in stenosis artery, the results present the effect of non-Newtonian blood. The effect of stenosis length and effect of non-Newtonian fluid on skin friction are consistent with the Casson model in which the skin friction increases with the increase of either stenosis length or the yield stress but the skin friction decreases with the increase of plasma viscosity coefficient. The effect of stenosis length and effect of non-Newtonian fluid on resistance of blood flow are contradictory. The resistance of blood flow (when normalized by non-Newtonian blood in normal artery) increases when either the plasma viscosity coefficient or the yield stress increases, but it decreases with the increase of stenosis length. The resistance of blood flow (when normalized by Newtonian blood in stenosis artery) decreases when either the plasma viscosity coefficient or the yield stress increases, but it decreases with the increase of stenosis length.

  2. Blood pressure and arterial stiffness in obese children and adolescents.

    Science.gov (United States)

    Hvidt, Kristian Nebelin

    2015-03-01

    Obesity, elevated blood pressure (BP) and arterial stiffness are risk factors for cardiovascular disease. A strong relationship exists between obesity and elevated BP in both children and adults. Obesity and elevated BP in childhood track into adult life increasing the risk of cardiovascular disease in adulthood. Ambulatory BP is the most precise measure to evaluate the BP burden, whereas carotid-femoral pulse wave velocity (cfPWV) is regarded as the gold standard for evaluating arterial (i.e. aortic) stiffness. These measures might contribute to a better understanding of obesity's adverse impact on the cardiovascular system, and ultimately a better prevention and treatment of childhood obesity. The overall aim of the present PhD thesis is to investigate arterial stiffness and 24-hour BP in obese children and adolescents, and evaluate whether these measures are influenced by weight reduction. The present PhD thesis is based on four scientific papers.  In a cross-sectional design, 104 severe obese children and adolescents with an age of 10-18 years were recruited when newly referred to the Children's Obesity Clinic, Holbæk University Hospital, and compared to 50 normal weighted age and gender matched control individuals. Ambulatory BP was measured, and cfPWV was investigated in two ways in respect to the distance measure of aorta; the previously recommended length - the so called subtracted distance, and the currently recommended length - the direct distance. In a longitudinal design, the obese patients were re-investigated after one-year of lifestyle intervention at the Children's Obesity Clinic in purpose of reducing the degree of obesity. In the cross-sectional design, the obese group had higher measures of obesity, while matched for age, gender and height, when compared to the control group. In the longitudinal design, 74% of the 72 followed up obese patients experienced a significant weight reduction. CfPWV was dependent on the method used to measure the

  3. ADRC or adaptive controller--A simulation study on artificial blood pump.

    Science.gov (United States)

    Wu, Yi; Zheng, Qing

    2015-11-01

    Active disturbance rejection control (ADRC) has gained popularity because it requires little knowledge about the system to be controlled, has the inherent disturbance rejection ability, and is easy to tune and implement in practical systems. In this paper, the authors compared the performance of an ADRC and an adaptive controller for an artificial blood pump for end-stage congestive heart failure patients using only the feedback signal of pump differential pressure. The purpose of the control system was to provide sufficient perfusion when the patients' circulation system goes through different pathological and activity variations. Because the mean arterial pressure is equal to the total peripheral flow times the total peripheral resistance, this goal was converted to an expression of making the mean aortic pressure track a reference signal. The simulation results demonstrated that the performance of the ADRC is comparable to that of the adaptive controller with the saving of modeling and computational effort and fewer design parameters: total peripheral flow and mean aortic pressure with ADRC fall within the normal physiological ranges in activity variation (rest to exercise) and in pathological variation (left ventricular strength variation), similar to those values of adaptive controller.

  4. A simple model of cerebral blood flow dependence on arterial blood pressure

    CERN Document Server

    Gersten, Alexander

    2011-01-01

    It is shown that the dependence of the cerebral blood flow (CBF) on mean arterial blood pressure (MABP) can be described with a simple model having the following assumptions. Below certain MABP (denoted as MABP1) there are no autoregulatory or feedback mechanisms influencing CBF. Between MABP1 and MABP2 (MABP at which breakthrough accurs) there is a linear (on MABP) dependent feedback with a sloap depending very much on the individual considered. The classical autoregulation model with a plateau in between MABP1 and MABP2 is a particular case of this model. The model describes well the experiments performed on dogs (Harper 1966), for which the individual feedback sloap parameter varied to great extent, indicating the importance of mesurments on individuals against averaged mesurments (or measurments on diffent individuals) which superficially support the classical autoregulation. New effect of decreased CBF, while increasing MABP, was observed.

  5. Physiological non-Newtonian blood flow through single stenosed artery

    Science.gov (United States)

    Mamun, Khairuzzaman; Rahman, Mohammad Matiur; Akhter, Most. Nasrin; Ali, Mohammad

    2016-07-01

    A numerical simulation to investigate the Non-Newtonian modelling effects on physiological flows in a three dimensional idealized artery with a single stenosis of 85% severity. The wall vessel is considered to be rigid. Oscillatory physiological and parabolic velocity profile has been imposed for inlet boundary condition. Where the physiological waveform is performed using a Fourier series with sixteen harmonics. The investigation has a Reynolds number range of 96 to 800. Low Reynolds number k - ω model is used as governing equation. The investigation has been carried out to characterize two Non-Newtonian constitutive equations of blood, namely, (i) Carreau and (ii) Cross models. The Newtonian model has also been investigated to study the physics of fluid. The results of Newtonian model are compared with the Non-Newtonian models. The numerical results are presented in terms of pressure, wall shear stress distributions and the streamlines contours. At early systole pressure differences between Newtonian and Non-Newtonian models are observed at pre-stenotic, throat and immediately after throat regions. In the case of wall shear stress, some differences between Newtonian and Non-Newtonian models are observed when the flows are minimum such as at early systole or diastole.

  6. Effect of volume expansion on systemic hemodynamics and central and arterial blood volume in cirrhosis

    DEFF Research Database (Denmark)

    Møller, Søren; Bendtsen, Flemming; Henriksen, Jens Henrik

    1995-01-01

    and in controls. METHODS: Thirty-nine patients with cirrhosis (12 patients with Child-Turcotte class A, 14 with class B, and 13 with class C) and 6 controls were studied. During hepatic vein catheterization, cardiac output, systemic vascular resistance, central and arterial blood volume, noncentral blood volume...... in patients with either class B or class C. Conversely, the noncentral blood volume increased in patients with class B and C. In both patients and controls, the cardiac output increased and the systemic vascular resistance decreased, whereas the mean arterial blood pressure did not change significantly......BACKGROUND & AIMS: Systemic vasodilatation in cirrhosis may lead to hemodynamic alterations with reduced effective blood volume and decreased arterial blood pressure. This study investigates the response of acute volume expansion on hemodynamics and regional blood volumes in patients with cirrhosis...

  7. Feeding through artificial membranes reduces fecundity for females of the blood-feeding insect, Rhodnius prolixus.

    Science.gov (United States)

    Chiang, R Gary; Chiang, Jennifer A

    2010-06-01

    The blood-feeding insect, Rhodnius prolixus, has been raised in the laboratory for close to 100 years. Various feeding techniques have been employed ranging from the use of warm-blooded hosts, to the use of previously collected blood offered through artificial membranes. This study compared the fecundity in mated and unmated females fed rabbit blood directly from the shaved belly of a rabbit to that of females fed defibrinated rabbit blood through an artificial membrane. These results confirm previous reports that this insect's feeding efficacy is reduced using an artificial membrane. It also demonstrates for the first time that the fecundity index, which measures the efficiency of turning the blood meal into eggs, is significantly reduced. We suggest that the natural feeding on a warm-blooded host may provide cues that have the short-term effect of enhancing the act of feeding and the long-term effect of increasing egg production efficiency. Until an artificial feeding method that does not interfere with feeding and fecundity is devised, experiments on reproduction in R. prolixus warrant the use of a warm-blooded host to emulate feeding in its natural setting.

  8. Fluid input control in burned patients with the aid of ultrasonic arterial blood pressure monitoring.

    Science.gov (United States)

    Banssillon, V; Latarjet, J

    1975-01-01

    Arterial blood pressure is nowadays easily and reliably measured with ultrasonic equipment. It correlates well with blood volume, and may therefore be used to guide fluid infusion in burned patients. Monitoring of blood pressure, instead of application of old-fashioned recipes, helps to avoid dangerous situations of hypovolemia or overload.

  9. Validation of continuous noninvasive arterial blood pressure measurements during general anesthesia

    NARCIS (Netherlands)

    Kalmar, A.F.; Vos, Jaap Jan; Weening, M.; Mooyaart, E.A.; Poterman, Marieke; Struys, Michel; Scheeren, Thomas

    2012-01-01

    Background:  Continuous invasive arterial blood pressure (IBP) monitoring remains the accepted gold standard for blood pressure monitoring because of its high accuracy. Several disadvantages of this method motivate the use of noninvasive intermittent blood pressure (NIBP) in most anesthesia cases de

  10. Retrograde arterial leg blood flow during tilt-back from a head-up posture: importance of capacitive flows when arterial pressure changes.

    Science.gov (United States)

    Sheriff, Don D; Nådland, Inger Helene; Toska, Karin

    2010-03-01

    The windkessel function of the arterial system converts the intermittent action of the heart into more continuous microcirculatory blood flow during diastole via the return of elastic energy stored in the walls of the arteries during systole. Might the same phenomenon occur regionally within the arterial system during tilting owing to regional differences in local arterial pressure imposed by gravity? We sought to test the hypothesis that during tilt-back from a head-up posture, the return of stored elastic energy in leg arteries would work to slow, or perhaps transiently reverse, the flow of blood in the femoral artery. Femoral artery blood flow and arterial pressure were recorded during tilt back from a 30 degrees head-up posture to supine (approximately 0.5 G) in young, healthy subjects (n = 7 males and 3 females) before and during clonidine infusion. During control (no drug) conditions femoral artery blood flow ceased for an entire heart beat during tilt-back. During clonidine infusion femoral artery blood flow reversed for at least one entire heart beat during tilt-back, i.e., blood flow in the retrograde direction in the femoral artery from the leg into the abdomen. Thus substantial capacitive effects of tilting on leg blood flow occur in humans during mild changes in posture.

  11. Phantom with Pulsatile Arteries to Investigate the Influence of Blood Vessel Depth on Pulse Oximeter Signal Strength

    Directory of Open Access Journals (Sweden)

    Hunor Santha

    2012-01-01

    Full Text Available This paper describes a three-layer head phantom with artificial pulsating arteries at five different depths (1.2 mm, 3.7 mm, 6.8 mm, 9.6 mm and 11.8 mm. The structure enables formation of spatially and temporally varying tissue properties similar to those of living tissues. In our experiment, pressure pulses were generated in the arteries by an electronically controlled pump. The physical and optical parameters of the layers and the liquid in the artificial arteries were similar to those of real tissues and blood. The amplitude of the pulsating component of the light returning from the phantom tissues was measured at each artery depth mentioned above. The build-up of the in-house-developed pulse oximeter used for performing the measurements and the physical layout of the measuring head are described. The radiant flux generated by the LED on the measuring head was measured to be 1.8 mW at 910 nm. The backscattered radiant flux was measured, and found to be 0.46 nW (0.26 ppm, 0.55 nW (0.31 ppm, and 0.18 nW (0.10 ppm for the 1.2 mm, 3.7 mm and 6.8 mm arteries, respectively. In the case of the 9.6 mm and 11.8 mm arteries, useful measurement data were not obtained owing to weak signals. We simulated the phantom with the arteries at the above-mentioned five depths and at two additional ones (2.5 mm and 5.3 mm in depth using the Monte Carlo method. The measurement results were verified by the simulation results. We concluded that in case of 11 mm source-detector separation the arteries at a depth of about 2.5 mm generate the strongest pulse oximeter signal level in a tissue system comprising three layers of thicknesses: 1.5 mm (skin, 5.0 mm (skull, and > 50 mm (brain.

  12. Relationship between the Direction of Ophthalmic Artery Blood Flow and Ocular Microcirculation before and after Carotid Artery Stenting

    Directory of Open Access Journals (Sweden)

    Masashi Ishii

    2016-01-01

    Full Text Available When internal carotid artery stenosis is accompanied by ocular ischemic syndrome, intervention is recommended to prevent irreversible visual loss. In this study, we used laser speckle flowgraphy to measure the ocular microcirculation in the optic nerve head before and after carotid artery stenting (CAS of 40 advanced internal carotid stenosis lesions from 37 patients. The aim was to investigate the relationship between ocular microcirculation and the direction of ophthalmic artery blood flow obtained by angiography. We found that there was a significant increase in blood flow after CAS (P=0.003. Peak systolic velocity as an indicator of the rate of stenosis was also significantly higher in the group with retrograde/undetected flow of the ophthalmic artery than in the group with antegrade flow (P=0.002. In all cases where retrograde flow of the ophthalmic artery was observed before stenting, the flow changed to antegrade after stenting. Through the use of laser speckle flowgraphy, this study found that CAS can improve ocular microcirculation. Furthermore, while patients displaying retrograde flow of the ophthalmic artery before stenting have a poor prognosis, CAS corrected the flow to antegrade, suggesting that visual loss can be prevented by improving the ocular microcirculation.

  13. Understanding the Impact of Arterial Stenosis on Blood Flow through a Tissue

    Science.gov (United States)

    Prakash, Elapulli Sankaranarayanan

    2015-01-01

    This article arises from the author's experience helping medical students apply core biophysical principles toward understanding cardiovascular physiology. The purpose of the article is illustrate how the effect of an arterial stenosis on blood flow to tissue supplied exclusively by the stenosed artery should be assessed. This discussion was…

  14. A Novel Laboratory Approach for the Demonstration of Hemodynamic Principles: The Arterial Blood Flow Reflection

    Science.gov (United States)

    Djelic, Marina; Mazic, Sanja; Zikic, Dejan

    2013-01-01

    In the frame of a laboratory training course for medicine students, a new approach for laboratory exercises has been applied to teach the phenomena of circulation. The exercise program included measurements of radial artery blood flow waveform for different age groups using a noninvasive optical sensor. Arterial wave reflection was identified by…

  15. Classification of peripheral occlusive arterial diseases based on symptoms, signs and distal blood pressure measurements

    DEFF Research Database (Denmark)

    Tønnesen, K H; Noer, Ivan; Paaske, William

    1980-01-01

    Systolic blood pressures at toe and ankle were measured in 459 consecutive patients with occlusive arterial disease. Fifty-eight per cent had intermittent claudication with arterial disease of all degrees of severity. Seventeen per cent complained of rest pain having toe systolic pressures below 30...

  16. [The possibilities for the transcranial monitoring of the blood flow in the circle of Willis arteries during operations on the brachiocephalic arteries and in heart operations].

    Science.gov (United States)

    Kuntsevich, G I; Kaĭdash, A N; Ter-Khachaturova, I E; Kovalevskaia, O A

    1995-01-01

    The paper gives the results of arterial blood flow monitoring in the circle of Willis via transcranial Doppler during 81 reparative operations on brachiocephalic arteries (including carotid endarterectomy from the internal carotid artery in 32 patients). Transcranial monitoring of blood flow supports the fact that there is a collateral reflow along the cerebral arteries during removal of the common carotid artery and that there is a relationship between the status of great arteries and arteries of Willis' circle. The paper also summaries the results of a comprehensive ultrasound study of 9 patients who have undergone reparative and plastic operations on the cardiac valves during extracorporeal circulation and general hypothermia. Blood flow was intraoperatively monitored in the arteries of the basis cerebri by using transcranial duplex scanning with colour Doppler flow mapping to evaluate not only hemodynamics, but also the embolic situation, as well as to check up how air was removed from the cardiac cavities by transesophageal echocardiography.

  17. ASSESSMENT OF VERTEBRAL ARTERIES BLOOD FLOW SPECTRAL DOPPLER INDICES IN COMPARISON WITH INTERNAL AND COMMON CAROTID ARTERIES BLOOD FLOW SPECTRAL DOPPLER INDICES

    Directory of Open Access Journals (Sweden)

    H. Mazaher

    2007-05-01

    Full Text Available Vertebrobasilar insufficiency is the cause of cerebrovascular accidents in 20% of cases. There are few reports regarding spectral Doppler indices (SDIs of vertebral arteries (VAs normal blood flow. The objective of this study was to provide basic reference data about SDIs of VAs normal blood flow separately and in comparison with internal carotid arteries (ICAs and common carotid arteries (CCAs normal blood flows SDIs. This cross-sectional study performed on 70 normal patients. Color Doppler sonography (CDS and spectral Doppler sonography (SDS of right and left VAs (RVA and LVA, right and left CCAs (RCCA and LCCA, right and left ICAs (RICA and LICA, were performed. The mean PSV, EDV, and RI values of RVA blood flow were as 41.60 ± 9.6 cm/s, 14.60 ± 3.7 cm/s and 0.65 ± 0.06, and the mean PSV, EDV and RI values of LVA blood flow were as 42.20 ± 10.2 cm/s, 15.20 ± 4.2 cm/s, and 0.64 ± 0.05, respectively. There was not statistically significant difference between the mean PSV, EDV and RI values of RVA and LVA blood flows. The mean PSV and EDV values of VAs blood flows were significantly lower than the values of CCAs and ICCAs blood flows, respectively. The mean RI value of VAs blood flows was significantly lower than the mean RI Value of CCAs blood flows, but there was not statistically significant difference between the mean RI value of VAs blood flows and the mean RI value of ICAs blood flows.

  18. Transcranial Doppler-determined change in posterior cerebral artery blood flow velocity does not reflect vertebral artery blood flow during exercise.

    Science.gov (United States)

    Washio, Takuro; Sasaki, Hiroyuki; Ogoh, Shigehiko

    2017-02-10

    We examined whether a change in posterior cerebral artery flow velocity (PCAv) reflected the posterior cerebral blood flow, in healthy subjects, during both static and dynamic exercise. PCAv and vertebral artery (VA) blood flow, as an index of posterior blood flow, were continuously measured during an exercise trial, using transcranial Doppler (TCD) ultrasonography and Doppler ultrasound, respectively. Static handgrip exercise significantly increased both PCAv and VA blood flow. Increasing intensity of dynamic exercise further increased VA blood flow from moderate exercise, while PCAv decreased to almost resting level. During both static and dynamic exercise, the PCA cerebrovascular conductance (CVC) index significantly decreased from rest (static and high intensity dynamic exercise; -11.5 ± 12.2% and -18.0 ± 16.8%; mean ± SD, respectively), despite no change in the CVC of VA. These results indicate that vasoconstriction occurred at PCA but not VA during exercise-induced hypertension. This discrepancy in vascular response to exercise between PCA and VA may be due to different cerebral arterial characteristics. Therefore, to determine the effect of exercise on posterior cerebral circulation, at least, we need to consider carefully which cerebral artery to measure, regardless of exercise mode.

  19. Non-Newtonian model study for blood flow through a tapered artery with a stenosis

    Directory of Open Access Journals (Sweden)

    Noreen Sher Akbar

    2016-03-01

    Full Text Available The blood flow through a tapered artery with a stenosis is analyzed, assuming the blood as tangent hyperbolic fluid model. The resulting nonlinear implicit system of partial differential equations is solved analytically with the help of perturbation method. The expressions for shear stress, velocity, flow rate, wall shear stress and longitudinal impedance are obtained. The variations of power law index m, Weissenberg number We, shape of stenosis n and stenosis size δ are discussed different type of tapered arteries.

  20. Strength training reduces arterial blood pressure but not sympathetic neural activity in young normotensive subjects

    Science.gov (United States)

    Carter, Jason R.; Ray, Chester A.; Downs, Emily M.; Cooke, William H.

    2003-01-01

    The effects of resistance training on arterial blood pressure and muscle sympathetic nerve activity (MSNA) at rest have not been established. Although endurance training is commonly recommended to lower arterial blood pressure, it is not known whether similar adaptations occur with resistance training. Therefore, we tested the hypothesis that whole body resistance training reduces arterial blood pressure at rest, with concomitant reductions in MSNA. Twelve young [21 +/- 0.3 (SE) yr] subjects underwent a program of whole body resistance training 3 days/wk for 8 wk. Resting arterial blood pressure (n = 12; automated sphygmomanometer) and MSNA (n = 8; peroneal nerve microneurography) were measured during a 5-min period of supine rest before and after exercise training. Thirteen additional young (21 +/- 0.8 yr) subjects served as controls. Resistance training significantly increased one-repetition maximum values in all trained muscle groups (P training did not affect MSNA or heart rate. Arterial blood pressures and MSNA were unchanged, but heart rate increased after 8 wk of relative inactivity for subjects in the control group (61 +/- 2 to 67 +/- 3 beats/min; P = 0.01). These results indicate that whole body resistance exercise training might decrease the risk for development of cardiovascular disease by lowering arterial blood pressure but that reductions of pressure are not coupled to resistance exercise-induced decreases of sympathetic tone.

  1. An artificial pancreas provided a novel model of blood glucose level variability in beagles.

    Science.gov (United States)

    Munekage, Masaya; Yatabe, Tomoaki; Kitagawa, Hiroyuki; Takezaki, Yuka; Tamura, Takahiko; Namikawa, Tsutomu; Hanazaki, Kazuhiro

    2015-12-01

    Although the effects on prognosis of blood glucose level variability have gained increasing attention, it is unclear whether blood glucose level variability itself or the manifestation of pathological conditions that worsen prognosis. Then, previous reports have not been published on variability models of perioperative blood glucose levels. The aim of this study is to establish a novel variability model of blood glucose concentration using an artificial pancreas. We maintained six healthy, male beagles. After anesthesia induction, a 20-G venous catheter was inserted in the right femoral vein and an artificial pancreas (STG-22, Nikkiso Co. Ltd., Tokyo, Japan) was connected for continuous blood glucose monitoring and glucose management. After achieving muscle relaxation, total pancreatectomy was performed. After 1 h of stabilization, automatic blood glucose control was initiated using the artificial pancreas. Blood glucose level varied for 8 h, alternating between the target blood glucose values of 170 and 70 mg/dL. Eight hours later, the experiment was concluded. Total pancreatectomy was performed for 62 ± 13 min. Blood glucose swings were achieved 9.8 ± 2.3 times. The average blood glucose level was 128.1 ± 5.1 mg/dL with an SD of 44.6 ± 3.9 mg/dL. The potassium levels after stabilization and at the end of the experiment were 3.5 ± 0.3 and 3.1 ± 0.5 mmol/L, respectively. In conclusion, the results of the present study demonstrated that an artificial pancreas contributed to the establishment of a novel variability model of blood glucose levels in beagles.

  2. Dynamics of the blood flow in the curved artery with the rolling massage

    Science.gov (United States)

    Yi, H. H.; Wu, X. H.; Yao, Y. L.

    2011-10-01

    Arterial wall shear stress and flow velocity are important factors in the development of some arterial diseases. Here, we aim to investigate the dynamic effect of the rolling massage on the property of the blood flow in the curved artery. The distributions of flow velocity and shear stress for the blood flow are computed by the lattice Boltzmann method, and the dynamic factors under different rolling techniques are studied numerically. The study is helpful to understand the mechanism of the massage and develop the massage techniques.

  3. Blood cleaner on-chip design for artificial human kidney manipulation.

    Science.gov (United States)

    Suwanpayak, N; Jalil, M A; Aziz, M S; Ismail, F D; Ali, J; Yupapin, P P

    2011-01-01

    A novel design of a blood cleaner on-chip using an optical waveguide known as a PANDA ring resonator is proposed. By controlling some suitable parameters, the optical vortices (gradient optical fields/wells) can be generated and used to form the trapping tools in the same way as optical tweezers. In operation, the trapping force is formed by the combination between the gradient field and scattering photons by using the intense optical vortices generated within the PANDA ring resonator. This can be used for blood waste trapping and moves dynamically within the blood cleaner on-chip system (artificial kidney), and is performed within the wavelength routers. Finally, the blood quality test is exploited by the external probe before sending to the destination. The advantage of the proposed kidney on-chip system is that the unwanted substances can be trapped and filtered from the artificial kidney, which can be available for blood cleaning applications.

  4. Blood flow changes after unilateral carotid artery ligation monitored by optical coherence tomography

    Science.gov (United States)

    Ma, Yushu; Liang, Chengbo; Suo, Yanyan; Zhao, Yuqian; Wang, Yi; Xu, Tao; Wang, Ruikang; Ma, Zhenhe

    2016-03-01

    Unilateral carotid artery ligation which could induce adaptive improvement is a classic model that has been widely used to study pathology of ischemic disease. In those studies, blood flow is an important parameter to characterize the ischemia. Optical coherence tomography (OCT) is a powerful imaging modality which can provide depth resolved images in biological tissue with high spatial and temporal resolution. SPF rats was anesthetized with isoflurane and divided into two groups. In first group, bilateral carotid artery was surgically exposed, and then left carotid artery was ligated. Blood flow changes of the contralateral carotid artery was monitored using high speed spectral domain optical coherence tomography, including the absolute flow velocity and the flow volume. In the other group, skull window was opened at the ipsilateral cerebral cortex of ligation and blood supply of small artery was measured before and after the ligation. The measured results demonstrate the blood supply compensation process after unilateral carotid artery ligation. With the superiority of high resolution, OCT is an effective technology in monitoring results of carotid artery after ligation.

  5. [Features of arterial blood pressure in elderly persons of different ethnic groups in Yakutsk].

    Science.gov (United States)

    Nikitin, Iu P; Tatarinova, O V; Neustroeva, V N; Shcherbakova, L V; Sidorov, A S

    2013-01-01

    The differences in arterial blood pressure in the sample of population in the age of 60 and older of different ethnic groups in Yakutsk, as well as its connection with the other cardiovascular diseases risk factors have been analyzed. It was shown that the average values of systolic and diastolic blood pressure in subsample of the Yakuts appeared to be lower than in Caucasoid gerontic persons. The average values of systolic arterial blood pressure both in the Yakuts and in the Caucasoids were detected higher than normal values in all age-dependent subgroups. The average values of diastolic blood pressure in both ethnic groups were within the limits of high normal level. From 60 to 90 years and older the decrease in systolic and diastolic arterial blood pressure was detected; it was more marked in Caucasoid gerontic persons. The average values of pulse pressure in the Yakuts and in the Caucasoids appeared to be higher than the existing standard and didn't have any differences in ethnic groups. In both ethnical subsamples, pulse pressure values increase was observed in persons of 60-89 years old and its decrease after 90. Persons with overweight, obesity, central (abdominal) obesity, dyslypoproteidemias irrespective of belonging to ethnical group were characterized as having higher levels of arterial blood pressure. Statistically significant differences in the levels of arterial blood pressure in the Yakuts and in the Caucasoids depending on hyperglycemia, smoking, the presence of burdened anamnesis, educational level, marital status was not detected.

  6. Blood transfusion requirement in surgery for femoral artery aneurysms

    DEFF Research Database (Denmark)

    Levi, N; Schroeder, T V

    1997-01-01

    Audit of blood usage in various surgical specialities have shown that over-ordering of blood is widespread, causing unnecessary pressure on the transfusion facilities and giving growing concern over the expense of cross-matching blood. The aim of this study was to assess the blood transfusion...

  7. Mathematical model for blood flow through a bifurcated artery using couple stress fluid.

    Science.gov (United States)

    Srinivasacharya, D; Madhava Rao, G

    2016-08-01

    In this article, the blood flow through a bifurcated artery with mild stenosis is investigated taking blood as couple stress fluid. The artery configuring bifurcation is assumed to be symmetric about the axis of the artery and straight cylinders of finite length. The governing equations are non-dimensionalized and coordinate transformation is used to convert the irregular boundary to a regular boundary. The resulting system of equations is solved numerically using the finite difference method. The variation of shear stress, flow rate and impedance near the apex with pertinent parameters are studied graphically. It has been noticed that shear stress, flow rate and impedance have been changing suddenly with all the parameters on both sides of the apex. This occurs because of the backflow of the streaming blood at the onset of the lateral junction and secondary flow near the apex in the daughter artery.

  8. Modeling of human colonic blood flow for a novel artificial anal sphincter system

    Institute of Scientific and Technical Information of China (English)

    Peng ZAN; Guo-zheng YAN; Hua LIU

    2008-01-01

    A novel artificial anal sphincter system has been developed to simulate the normal physiology of the human anorectum. With the goal of engineering a safe and reliable device, the model of human colonic blood flow has been built and the relationship between the colonic blood flow rate and the operating occlusion pressure of the anorectum is achieved. The tissue ischemia is analyzed based on constitutive relations for human anorectum. The results suggest that at the planned operating occlusion pressure of less than 4 kPa the artificial anal sphincter should not risk the vaseularity of the human colon.

  9. The status of failure and reliability testing of artificial blood pumps.

    Science.gov (United States)

    Patel, Sonna M; Throckmorton, Amy L; Untaroiu, Alexandrina; Allaire, Paul E; Wood, Houston G; Olsen, Don B

    2005-01-01

    Artificial blood pumps are today's most promising bridge-to-transplant, bridge-to-recovery, and destination therapy solutions for patients with congestive heart failure. There is a critical need for increased reliability and safety as the next generation of artificial blood pumps approach final development for long-term destination therapy. To date, extensive failure and reliability studies of these devices are considered intellectual property and thus remain unpublished. Presently, the Novacor N100PC, Thoratec VAD, and HeartMate LVAS (IP and XVE) comprise the only four artificial blood pumps commercially available for the treatment of congestive heart failure in the United States. The CardioWest TAH recently received premarket approval from the US Food and Drug Administration. With investigational device exemptions, the AB-180, AbioCor, LionHeart, DeBakey, and Flowmaker are approved for clinical testing. Other blood pumps, such as the American BioMed-Baylor TAH, CorAide, Cleveland Clinic-Nimbus TAH, HeartMate III, Hemadyne, and MagScrew TAH are currently in various stages of mock loop and animal testing, as indicated in published literature. This article extensively reviews in vitro testing, in vivo testing, and the early clinical testing of artificial blood pumps in the United States, as it relates to failure and reliability. This detailed literature review has not been published before and provides a thorough documentation of available data and testing procedures regarding failure and reliability of these various pumps.

  10. Bed bugs, their blood sources and life history parameters: a comparison of artificial and natural feeding.

    Science.gov (United States)

    Aak, A; Rukke, B A

    2014-03-01

    A blood-feeding system that utilizes a small amount of whole heparinized human blood in parafilm bags is described in detail, and similarities and differences between artificially fed and naturally rodent-fed bed bugs (Hemiptera: Cimicidae) are discussed. Blood with high levels of heparin (10%) was unsuitable for artificial colony rearing, whereas bed bugs fed on 1% heparinized blood and those that naturally ingested rat blood completed their lifecycle with similar stage structures over time, with no significant differences in mortality. No differences in feeding efficiency or fertility were found in a direct comparison of bed bugs maintained under each of these two treatments, but analysis of the full lifecycle revealed that artificially fed bed bugs became significantly smaller and laid fewer eggs than rodent-fed bed bugs. The level of membrane stretching regulated the number of bed bugs that fed. When the membrane was stretched to twice its length and width, 96% of bed bugs successfully fed through the parafilm. Whole heparinized blood that was stored at 6 °C for ≥ 14 days failed to retain its nutritional value and the amount of blood consumed and number of consecutive moults were significantly reduced.

  11. Membrane concepts for blood purification : towards improved artificial kidney devices

    NARCIS (Netherlands)

    Tijink, M.S.L.

    2013-01-01

    The research presented in this thesis is about the fabrication and characterization of new membranes for blood purification. A novel membrane concept is proposed to combine diffusion and adsorption in one step to remove uremic retention solutes. A membrane with embedded functionalized particles, a s

  12. Effect of volume expansion on systemic hemodynamics and central and arterial blood volume in cirrhosis

    DEFF Research Database (Denmark)

    Møller, S; Bendtsen, F; Henriksen, Jens Henrik Sahl

    1995-01-01

    and in controls. METHODS: Thirty-nine patients with cirrhosis (12 patients with Child-Turcotte class A, 14 with class B, and 13 with class C) and 6 controls were studied. During hepatic vein catheterization, cardiac output, systemic vascular resistance, central and arterial blood volume, noncentral blood volume...

  13. Changes of Blood Flow Volume in the Superior Mesenteric Artery and Brachial Artery with Abdominal Thermal Stimulation

    Directory of Open Access Journals (Sweden)

    Shin Takayama

    2011-01-01

    Full Text Available In traditional Chinese medicine, moxibustion is a local thermal therapy that is used for several conditions. Quantifying the effects of moxibustion therapy has been difficult because the treatment temperature depends on the physician's experience, and the temperature distribution in the target area is not uniform. This prospective observational study aims to quantify the effect of local thermal stimulation to the abdomen. We developed a heat transfer control device (HTCD for local thermal stimulation. Twenty-four healthy subjects were enrolled and they underwent abdominal thermal stimulation to the para-umbilical region with the device for 20 min. Blood flow volume in the superior mesenteric artery (SMA and brachial artery (BA, the heart rate and the blood pressure were measured at rest, 15 min after starting thermal stimulation and 10, 20, 30 and 40 min after completing thermal stimulation. Blood flow parameters were measured by high-resolution ultrasound. In the SMA, blood flow volume was significantly increased during thermal stimulation (, as well as at 10 min ( and 20 min ( after stimulation. In the BA, blood flow volume decreased at 40 min after stimulation (. In conclusion we could quantify the effect of local thermal stimulation with an HTCD and high-resolution ultrasound. Thermal stimulation of the para-umbilical region increased blood flow in the SMA 20 min after stimulation in healthy subjects.

  14. Arterial dysfunction but maintained systemic blood pressure in cavin-1-deficient mice.

    Directory of Open Access Journals (Sweden)

    Karl Swärd

    Full Text Available Caveolae are omega-shaped plasma membrane micro-domains that are abundant in cells of the vascular system. Formation of caveolae depends on caveolin-1 and cavin-1 and lack of either protein leads to loss of caveolae. Mice with caveolin-1 deficiency have dysfunctional blood vessels, but whether absence of cavin-1 similarly leads to vascular dysfunction is not known. Here we addressed this hypothesis using small mesenteric arteries from cavin-1-deficient mice. Cavin-1-reporter staining was intense in mesenteric arteries, brain arterioles and elsewhere in the vascular system, with positive staining of both endothelial and smooth muscle cells. Arterial expression of cavin-1, -2 and -3 was reduced in knockout (KO arteries as was expression of caveolin-1, -2 and -3. Caveolae were absent in the endothelial and smooth muscle layers of small mesenteric arteries as determined by electron microscopy. Arginase, a negative regulator of nitric oxide production, was elevated in cavin-1 deficient arteries as was contraction in response to the α1-adrenergic agonist cirazoline. Detailed assessment of vascular dimensions revealed increased media thickness and reduced distensibility, arguing that enhanced contraction was due to increased muscle mass. Contrasting with increased α1-adrenergic contraction, myogenic tone was essentially absent and this appeared to be due in part to increased nitric oxide production. Vasomotion was less frequent in the knock-out vessels. In keeping with the opposing influences on arterial resistance of increased agonist-induced contractility and reduced myogenic tone, arterial blood pressure was unchanged in vivo. We conclude that deficiency of cavin-1 affects the function of small arteries, but that opposing influences on arterial resistance balance each other such that systemic blood pressure in unstressed mice is well maintained.

  15. Artificial Blood Substitutes: First Steps on the Long Route to Clinical Utility

    OpenAIRE

    2016-01-01

    The 21st century is challenging for human beings. Increased population growth, population aging, generation of new infectious agents, and natural disasters are some threatening factors for the current state of blood transfusion. However, it seems that science and technology not only could overcome these challenges but also would turn many human dreams to reality in this regard. Scientists believe that one of the future evolutionary innovations could be artificial blood substitutes that might ...

  16. Repeated action of a constant magnetic field on the blood coagulation system in artificially produced anemia

    Science.gov (United States)

    Zabrodina, L. V.

    1974-01-01

    Changes are discussed in the coagulatory system of the blood in rabbits under the influence of a constant magnetic field of an intensity of 2500 oersteds against the background of artificially induced anemia. Reversibility of the changes produced and the presence of the adaptational effect are noted. Taking all this into consideration, the changes involving the coagulatory system of the blood which arise under the influence of a constant magnetic field may be considered to have a nerve-reflex nature.

  17. Colonization of Lutzomyia shannoni (Diptera: Psychodidae) utilizing an artificial blood feeding technique.

    Science.gov (United States)

    Mann, Rajinder S; Kaufman, Phillip E

    2010-12-01

    Laboratory colonization of hematophagous insects must include an efficient method of blood feeding, preferably by artificial means. Strict rules for obtaining animal use permits, extensive animal maintenance costs, and indirect anesthesia effects on animal health warrant the development of an artificial membrane feeding technique for sand fly colonization in laboratories. An attempt was made to colonize Lutzomyia shannoni using an artificial blood feeding membrane to replace the use of live animals commonly used for sand fly blood-feeding purposes. Lutzomyia shannoni readily fed through a pig intestine membrane exposed at an angle of 45°. However, it did not feed through a chicken skin membrane. Olfactory attractants were unable to improve blood-feeding efficiency. Plaster of Paris was the most suitable oviposition substrate. Female L. shannoni adults laid no eggs on moist sand substrate. Sand fly adults held in groups of ten or more laid higher numbers of eggs than did individually maintained sand flies. Inclusion of the L. longipalpis oviposition hormone dodecanoic acid or the presence of previously laid eggs did not stimulate L. shannoni oviposition. The average L. shannoni egg, larval, and pupal duration were 9.3, 36.7, and 17.8 days, respectively. The addition of a 20% sugar solution improved adult female longevity. Females survived longer (14.8 days) than males (11.9 days). Lutzomyia shannoni was successfully colonized in the laboratory for up to four generations using this artificial membrane technique.

  18. EFFECT OF ACUPUNCTURE ON BLOOD FLOW OF VERTEBRAL AND BASILAR ARTERIES IN STROKE PATIENTS

    Institute of Scientific and Technical Information of China (English)

    吕建明; 王伟志

    2004-01-01

    Objective: To observe the short-term effect and long-term effect of acupuncture on blood flow of vertebral and basilar arteries in stroke patients.Methods: A total of 58 stroke patients (34 males and 24 females) were agreed to participate in this study, and changes of blood flow of the vertebral and basilar arteries were detected after one week's and 45 days' continuous acupuncture treatment by using a Doppler's ultrasonic diagnosis apparatus.Bilateral Fengchi (GB 20), Wangu (GB 12), Tianzhu (BL 10), etc.were punctured and stimulated with small amplitude, high frequency and twirling-reinforcing method for 3 min.The treatment was conducted once daily.Results: Following one week's and 45 days' acupuncture treatment, diastolic velocity (DV), systolic velocity (SV) and mean velocity (MV) of the basilar artery increased significantly in comparison with pre-treatment (P0.05).Results indicated that acupuncture treatment could effectively improve blood supply of the basilar artery and regulate the uneven blood flow of the bilateral vertebral arteries.Conclusion: Acupuncture treatment can raise blood flow of the brain in stroke patients.

  19. Heat stress redistributes blood flow in arteries of the brain during dynamic exercise.

    Science.gov (United States)

    Sato, Kohei; Oue, Anna; Yoneya, Marina; Sadamoto, Tomoko; Ogoh, Shigehiko

    2016-04-01

    We hypothesized that heat stress would decrease anterior and posterior cerebral blood flow (CBF) during exercise, and the reduction in anterior CBF would be partly associated with large increase in extracranial blood flow (BF). Nine subjects performed 40 min of semirecumbent cycling at 60% of the peak oxygen uptake in hot (35°C; Heat) and thermoneutral environments (25°C; Control). We evaluated BF and conductance (COND) in the external carotid artery (ECA), internal carotid artery (ICA), and vertebral artery (VA) using ultrasonography. During the Heat condition, ICA and VA BF were significantly increased 10 min after the start of exercise (P brain arteries to exercise, which resulted in an alteration in the distribution of cardiac output. Moreover, a hyperthermia-induced increase in extracranial BF might compromise anterior CBF during exercise with heat stress.

  20. Measurement of Blood Pressure Using an Arterial Pulsimeter Equipped with a Hall Device

    Directory of Open Access Journals (Sweden)

    Jong-Gu Choi

    2011-01-01

    Full Text Available To measure precise blood pressure (BP and pulse rate without using a cuff, we have developed an arterial pulsimeter consisting of a small, portable apparatus incorporating a Hall device. Regression analysis of the pulse wave measured during testing of the arterial pulsimeter was conducted using two equations of the BP algorithm. The estimated values of BP obtained by the cuffless arterial pulsimeter over 5 s were compared with values obtained using electronic or liquid mercury BP meters. The standard deviation between the estimated values and the measured values for systolic and diastolic BP were 8.3 and 4.9, respectively, which are close to the range of values of the BP International Standard. Detailed analysis of the pulse wave measured by the cuffless radial artery pulsimeter by detecting changes in the magnetic field can be used to develop a new diagnostic algorithm for BP, which can be applied to new medical apparatus such as the radial artery pulsimeter.

  1. Obese children and adolescents have elevated nighttime blood pressure independent of insulin resistance and arterial stiffness

    DEFF Research Database (Denmark)

    Hvidt, Kristian N; Olsen, Michael H; Holm, Jens-Christian

    2014-01-01

    BACKGROUND: Insulin resistance has been related to elevated blood pressure (BP) in obese children and may adversely affect the vasculature by arterial stiffening. The objective was to investigate whether daytime and nighttime BP were elevated and related to insulin resistance and arterial stiffness...... in obese children and adolescents. METHODS: Ninety-two obese patients aged 10-18 years were compared with 49 healthy control individuals. Insulin resistance was measured as the homeostatic assessment model (HOMA), and arterial stiffness was measured as carotid-femoral pulse wave velocity (cfPWV). RESULTS...... analyses, the higher nighttime BP in the obese group was independent of logHOMA and cfPWV. CONCLUSIONS: Obese children had a higher nighttime BP when compared with the control group independently of insulin resistance and arterial stiffness. No relationship was found between insulin resistance and arterial...

  2. Trans-illuminated laser speckle imaging of collateral artery blood flow in ischemic mouse hindlimb

    OpenAIRE

    Meisner, Joshua K.; Niu, Jacqueline; Sumer, Suna; Price, Richard J.

    2013-01-01

    Abstract. The mouse ischemic hindlimb model is used widely for studying collateral artery growth (i.e., arteriogenesis) in response to increased shear stress. Nonetheless, precise measurements of regional shear stress changes along individual collateral arteries are lacking. Our goal is to develop and verify trans-illumination laser speckle flowmetry (LSF) for this purpose. Studies of defibrinated bovine blood flow through tubes embedded in tissue-mimicking phantoms indicate that trans-illumi...

  3. [Peculiarities of application of a cell saver apparatus in neonathal cardiosurgery using artificial blood circulation].

    Science.gov (United States)

    Kuz'menko, S O; Chasovs'kyĭ, K S

    2015-01-01

    Elaborated and introduced into the practice method of the blood preservation, while correction of complex inborn heart failures (IHF) in a newborn babies, was proposed. It assumes application of system for intraoperative reinfusion of own erythrocytes with processing of residual perfusate and their reinfusion in a postperfusion period. Impact of the blood preservation on volume of a donor's blood components, hematological indices and methods of application of washed erythrocytes while correction of complex IHF in a newborn babies were presented. The method was applied in 47 newborn babies, to whom an arterial switch was performed for the main vessels transposition.

  4. Finite volume numerical solution to a blood flow problem in human artery

    Science.gov (United States)

    Wijayanti Budiawan, Inge; Mungkasi, Sudi

    2017-01-01

    In this paper, we solve a one dimensional blood flow model in human artery. This model is of a non-linear hyperbolic partial differential equation system which can generate either continuous or discontinuous solution. We use the Lax–Friedrichs finite volume method to solve this model. Particularly, we investigate how a pulse propagates in human artery. For this simulation, we give a single sine wave with a small time period as an impluse input on the left boundary. The finite volume method is successful in simulating how the pulse propagates in the artery. It detects the positions of the pulse for the whole time period.

  5. Effect of artificial photoperiod on the blood cell indices of the catfish, Clarias batrachus

    Directory of Open Access Journals (Sweden)

    S Srivastava

    2010-04-01

    Full Text Available The present study is aimed to assess the influence of artificial photoperiod on the blood cell indices of an Indian catfish, Clarias batrachus(Linn.. Blood samples taken from adult fishes exposed to artificial photoperiod of 24L:0D and 0L:24D for a short period of 24 hrs, were analyzed for total RBC, total WBC, differential leukocyte count (DLC and some physiological variables – glucose and chloride. The total RBC and WBC counts were unaffected by both the artificial photoperiod regimes. However, lymphopenia (p<.05 and neutrophilia (p<.05 were observed under 24L:0D photoperiod. Blood chloride levels were significantly higher (p<.05 in 24L:0D whereas blood glucose levels remained unchanged in both the photoperiod treatments. The 0L:24D photoperiod did not produce any significant change in the blood cell indices neither in the physiological variables. The findings indicate that exposure to continuous light for as short a duration as of 24 hrs elicits stress responses in the leukocyte profile of this nocturnal fish and highlights the role of leukocyte profile as potential stress biomarkers in vertebrates.

  6. Sodium hydrosulfide alleviates pulmonary artery collagen remodeling in rats with high pulmonary blood flow.

    Science.gov (United States)

    Li, Xiaohui; Du, Junbao; Jin, Hongfang; Geng, Bin; Tang, Chaoshu

    2008-11-01

    This study aimed to explore the effect of sodium hydrosulfide (NaHS) on pulmonary artery collagen remodeling in rats with high pulmonary blood flow. Thirty-two Sprague-Dawley rats were randomly divided into a sham group, shunt group, sham + NaHS (an H2S donor) group, and shunt + NaHS group. After 11 weeks of shunting, mean pulmonary artery pressure (MPAP), relative median area (RMA) of pulmonary arteries, H2S concentration in lung tissues, plasma endothelin-1 (ET-1) levels, and ET-1 mRNA in lung tissues were investigated. Collagen I and collagen III were evaluated by immunohistochemistry. Hydroxyproline assay and Sirius-red staining were performed. Matrix metalloproteinase-13 (MMP-13), tissue inhibitor of metalloproteinase-1 (TIMP-1), and connective tissue growth factor (CTGF) were evaluated by immunohistochemistry. After 11 weeks of shunting, rats showed a significant pulmonary hypertension and pulmonary artery collagen remodeling in association with a decrease in lung tissue H2S content. After NaHS treatment for 11 weeks, lung tissue H(2)S content was increased, whereas MPAP was attenuated and RMA was reduced. Meanwhile, pulmonary artery collagen I and collagen III protein expressions of intra-acinar pulmonary arteries were inhibited, but MMP-13/TIMP-1 ratio was augmented with a decreased plasma ET-1 content and lung tissue ET-1mRNA and CTGF expressions. The downregulation of H(2)S is involved in the development of pulmonary artery collagen remodeling induced by high pulmonary blood flow.

  7. [Intralobar pulmonary sequestration with multiple arterial blood supply].

    Science.gov (United States)

    Uroz Tristán, J; Mogueya, S A; Poenaru, D; Martínez Lagares, F; Arteaga García, R; Sanchís Solera, L; López-Pinto Ruiz, J

    1994-04-01

    We report the case of a 4 years old boy, who presented at our institution with reiterative neumonia affecting left basal lobe. Anomalous vascular appearance was detected in the chest x-ray. With the suspicion of pulmonary sequestration we carried on Digital Intravenous Angiography by Substraction (DIVAS) and aortogram. The anomalous systemic arterial supply was formed by 6 vessels coming from the thoracic aorta and going into the left lower lobe basal segment. Lobectomy was performed and previous diagnosis was confirmed pathologically.

  8. Effects of fluid recirculation on mass transfer from the arterial surface to flowing blood

    Institute of Scientific and Technical Information of China (English)

    Zhi-Guo Zhang; Xi-Wen Zhang; Ying-Xi Liu

    2012-01-01

    The effect of disturbed flow on the mass transfer from arterial surface to flowing blood was studied numerically,and the results were compared with that of our previous work.The arterial wall was assumed to be viscoelastic and the blood was assumed to be incompressible and non-Newtonian fluid,which is more close to human arterial system.Numerical results indicated that the mass transfer from the arterial surface to flowing blood in regions of disturbed flow is positively related with the wall shear rates and it is significantly enhanced in regions of disturbed flow with a local minimum around the reattachment point which is higher than the average value of the downstream.Therefore,it may be implied that the accumulation of cholesterol or lipids within atheromatous plaques is not caused by the reduced efflux of cholesterol or lipids,but by the infiltration of the LDL (low-density lipoprotein) from the flowing blood to the arterial wall.

  9. Numerical investigation of MHD flow of blood and heat transfer in a stenosed arterial segment

    Science.gov (United States)

    Majee, Sreeparna; Shit, G. C.

    2017-02-01

    A numerical investigation of unsteady flow of blood and heat transfer has been performed with an aim to provide better understanding of blood flow through arteries under stenotic condition. The blood is treated as Newtonian fluid and the arterial wall is considered to be rigid having deposition of plaque in its lumen. The heat transfer characteristic has been analyzed by taking into consideration of the dissipation of energy due to applied magnetic field and the viscosity of blood. The vorticity-stream function formulation has been adopted to solve the problem using implicit finite difference method by developing well known Peaceman-Rachford Alternating Direction Implicit (ADI) scheme. The quantitative profile analysis of velocity, temperature and wall shear stress as well as Nusselt number is carried out over the entire arterial segment. The streamline and temperature contours have been plotted to understand the flow pattern in the diseased artery, which alters significantly in the downstream of the stenosis in the presence of magnetic field. Both the wall shear stress and Nusselt number increases with increasing magnetic field strength. However, wall shear stress decreases and Nusselt number enhances with Reynolds number. The results show that with an increase in the magnetic field strength upto 8 T, does not causes any damage to the arterial wall, but the study is significant for assessing temperature rise during hyperthermic treatment.

  10. Evaluation of artificial pancreas technology for continuous blood glucose monitoring in dogs.

    Science.gov (United States)

    Mori, Akihiro; Lee, Peter; Yokoyama, Takeshi; Oda, Hitomi; Saeki, Kaori; Miki, Yohei; Nozawa, Satoshi; Azakami, Daigo; Momota, Yutaka; Makino, Yuki; Matsubara, Takako; Osaka, Motohisa; Ishioka, Katsumi; Arai, Toshiro; Sako, Toshinori

    2011-06-01

    Artificial pancreas technology, involving "closed-loop" controls with real-time blood glucose monitoring, has been increasing in reliability as its potential for clinical use and application grows. One such device, based on this technology, is the STG-22 (Nikkiso Co., Ltd., Tokyo, Japan) artificial pancreas apparatus. In order to assess the reliability and accuracy of the device for measuring blood glucose, it is important to compare its readings to those obtained using a 'gold standard' method, such as the hexokinase method. Therefore, in the present study, canine blood [glucose] measurements using the STG-22 were compared to those obtained using a previously established commercial reagent, Quickauto-Neo GLU-HK. Furthermore, two different sample types (whole blood versus plasma constituent) were compared to determine which sample type results in more accurate and optimal readings with the STG-22. Given that the STG-22 was not primarily designed for canine blood samples, results for canine blood samples were not accurate. Measurements performed by the STG-22 with whole blood were significantly lower than reference [glucose] counterparts. Alternatively, an opposite trend was observed with plasma measurements that were significantly higher. A conversion format using the following formula, Hexokinase [glucose] = STG-22 [glucose] × 1.407 + 1.532, was observed with canine samples in our study.

  11. Blood cleaner on-chip design for artificial human kidney manipulation

    Directory of Open Access Journals (Sweden)

    Suwanpayak N

    2011-05-01

    Full Text Available N Suwanpayak1, MA Jalil2, MS Aziz3, FD Ismail3, J Ali3, PP Yupapin11Nanoscale Science and Engineering Research Alliance (N'SERA, Advanced Research Center for Photonics, Faculty of Science, King Mongkut's Institute of Technology, Ladkrabang, Bangkok, Thailand; 2Ibnu Sina Institute of Fundamental Science Studies (IIS, 3Institute of Advanced Photonics Science, Nanotechnology Research Alliance, Universiti Teknologi Malaysia, Johor Bahru, MalaysiaAbstract: A novel design of a blood cleaner on-chip using an optical waveguide known as a PANDA ring resonator is proposed. By controlling some suitable parameters, the optical vortices (gradient optical fields/wells can be generated and used to form the trapping tools in the same way as optical tweezers. In operation, the trapping force is formed by the combination between the gradient field and scattering photons by using the intense optical vortices generated within the PANDA ring resonator. This can be used for blood waste trapping and moves dynamically within the blood cleaner on-chip system (artificial kidney, and is performed within the wavelength routers. Finally, the blood quality test is exploited by the external probe before sending to the destination. The advantage of the proposed kidney on-chip system is that the unwanted substances can be trapped and filtered from the artificial kidney, which can be available for blood cleaning applications.Keywords: optical trapping, blood dialysis, blood cleaner, human kidney manipulation

  12. Predicting Blood Transfusion Factors in Coronary Artery Bypass Surgery

    Directory of Open Access Journals (Sweden)

    L. Kasraian

    2007-04-01

    Full Text Available Introduction & Objective: The ability to predict the use of blood components during bypass surgery will improve the blood banks ability to provide efficient service.Materials and Methods: This is a retrospective cross-sectional study that was carried out on patients that underwent CABG in Shiraz Namazi hospital in 2004. The sample size was 480 and we did systematic random sampling, and a questionnaire contained factors that effect on blood need was filling out. Independent t-test, multivariate logistic regression and Poason correlation were used for data analysis.Results: The average age of patients was 59.15±10.6 years, 69.2% were male and the mean Hct before surgery was 39.86±6.38% and after operation was 32.68±5.84% and the duration of surgery was 2 hours and 48 minutes. The average of pack cell was 5.76±1.52 unit and average of FFP was 2.82±7.72 unit. There was not significant correlation between ages, weighs, Hct before and after, sex and pack cell use (P> 0.05. The use of pack cell and FFP were more in urgent surgery in diabetic patients and vascular disease (P< 0.05.Conclusion: It seems that the rate of blood demanding in proportion to blood use is logical but the rate of blood usage is more than blood usage in other countries with considering of immunological and non-immunological complication of blood products, the heart surgeons must do special concern about the making decision for blood use.

  13. The Blood Flow at Arterial Bifurcations Simulated by the Lattice Boltzmann Method

    Institute of Scientific and Technical Information of China (English)

    JI Yu-Pin; KANG Xiu-Ying; LIU Da-He

    2009-01-01

    The Programmed model of non-Newtonian blood flow (the Casson model) at arterial bifurcations is established by the lattice Boltzmann method. The blood flow field under different Reynolds numbers is simulated, and distri-bution of dynamic factors such as flow velocity, shear stress, pressure and shear rate are presented. The existence of the fluid separation zone is analyzed. This provides a basis for further studies of the relationship between hemodynamic factors and pathogenesis, as well as a reference for a better understanding of the pathological changes and location of sediments, and the plague factor in arteries.

  14. [Doppler studies of arterial blood flow in the uterus during labor].

    Science.gov (United States)

    Fendel, H; Fendel, M; Pauen, A; Liedtke, B; Schonlau, H; Warnking, R

    1984-01-01

    By the pulsed doppler method the arterial uterine blood velocity was studied in 19 patients with contractions before and during labour. It is shown, that uterine contractions reduce blood velocity significantly. Normally there is a low resistance in uterine arteries, so that the diastolic flow is nearly as high as the systolic flow. In uterine contractions the vascular resistance increases. Systolic flow is reduced slightly and diastolic flow severely or completely. But a complete zero-flow couldn't observed in any studied uterine contraction.

  15. Ultrasonic Doppler measurement of renal artery blood flow

    Science.gov (United States)

    Freund, W. R.; Beaver, W. L.; Meindl, J. D.

    1976-01-01

    Studies were made of (1) blood flow redistribution during lower body negative pressure (LBNP), (2) the profile of blood flow across the mitral annulus of the heart (both perpendicular and parallel to the commissures), (3) testing and evaluation of a number of pulsed Doppler systems, (4) acute calibration of perivascular Doppler transducers, (5) redesign of the mitral flow transducers to improve reliability and ease of construction, and (6) a frequency offset generator designed for use in distinguishing forward and reverse components of blood flow by producing frequencies above and below the offset frequency. Finally methodology was developed and initial results were obtained from a computer analysis of time-varying Doppler spectra.

  16. Planning-free cerebral blood flow territory mapping in patients with intracranial arterial stenosis.

    Science.gov (United States)

    Arteaga, Daniel F; Strother, Megan K; Davis, L Taylor; Fusco, Matthew R; Faraco, Carlos C; Roach, Brent A; Scott, Allison O; Donahue, Manus J

    2016-07-07

    A noninvasive method for quantifying cerebral blood flow and simultaneously visualizing cerebral blood flow territories is vessel-encoded pseudocontinuous arterial spin labeling MRI. However, obstacles to acquiring such information include limited access to the methodology in clinical centers and limited work on how clinically acquired vessel-encoded pseudocontinuous arterial spin labeling data correlate with gold-standard methods. The purpose of this work is to develop and validate a semiautomated pipeline for the online quantification of cerebral blood flow maps and cerebral blood flow territories from planning-free vessel-encoded pseudocontinuous arterial spin labeling MRI with gold-standard digital subtraction angiography. Healthy controls (n = 10) and intracranial atherosclerotic disease patients (n = 34) underwent 3.0 T MRI imaging including vascular (MR angiography) and hemodynamic (cerebral blood flow-weighted arterial spin labeling) MRI. Patients additionally underwent catheter and/or CT angiography. Variations in cross-territorial filling were grouped according to diameters of circle of Willis vessels in controls. In patients, Cohen's k-statistics were computed to quantify agreement in perfusion patterns between vessel-encoded pseudocontinuous arterial spin labeling and angiography. Cross-territorial filling patterns were consistent with circle of Willis anatomy. The intraobserver Cohen's k-statistics for cerebral blood flow territory and digital subtraction angiography perfusion agreement were 0.730 (95% CI = 0.593-0.867; reader one) and 0.708 (95% CI = 0.561-0.855; reader two). These results support the feasibility of a semiautomated pipeline for evaluating major neurovascular cerebral blood flow territories in patients with intracranial atherosclerotic disease.

  17. Evaluation of restenosis, renal function and blood pressure after the renal artery stenting in patients with atherosclerosis renovascular disease

    Institute of Scientific and Technical Information of China (English)

    王焱

    2006-01-01

    Objective To evaluate the restenosis, renal function and blood pressure after renal artery stenting in patients with atherosclerosis renovascular disease. Methods Percutaneous renal artery stent (PTRAS) was performed in 135 patients with single or bilateral renal artery stenosis (≥70%). Clinical data of above patients were studied during follow-up period. Results A total of 147

  18. Queixa de vertigem e hipertensão arterial Vertigo complaint and blood hypertension

    Directory of Open Access Journals (Sweden)

    Luciana Lozza de Moraes Marchiori

    2007-03-01

    Full Text Available OBJETIVO: investigar a presença de queixa de vertigem em pacientes de meia idade com hipertensão arterial. MÉTODOS: estudo do tipo prospectivo, transversal. Composto por 154 indivíduos de ambos os gêneros com idade de 45 a 64 anos. A hipertensão foi verificada por meio de medição da pressão arterial e de questionário sistematizado sobre hipertensão e uso de medicamentos para pressão arterial. A queixa de vertigem foi verificada por meio de anamnese audiológica. RESULTADOS: pode-se verificar que existe associação significante entre hipertensão arterial e queixa de vertigem. CONCLUSÃO: os resultados da presente pesquisa, por meio da constatação da associação entre hipertensão arterial e queixa de vertigem, servirão de base a profissionais da área de saúde que estão envolvidos com sintomas provenientes da hipertensão arterial.PURPOSE: to investigate the presence of vertigo complaint in middle-aged hypertension patients. METHODS: a transversal study. Composed by 154 patients of both genders, aged from 45 to 64 years, included in the research after sample estimation. Hypertension was verified through blood pressure readings and by a systematized questionnaire about hypertension and the use of medication for blood pressure. Vertigo was assessed through audiological anamneses. RESULTS: there is a significant association between blood hypertension and vertigo. CONCLUSION: the results in this research, through evidence of association between blood hypertension and vertigo complaint, can be a base for health professionals concerned with alterations caused by blood hypertension.

  19. Trans-illuminated laser speckle imaging of collateral artery blood flow in ischemic mouse hindlimb.

    Science.gov (United States)

    Meisner, Joshua K; Niu, Jacqueline; Sumer, Suna; Price, Richard J

    2013-09-01

    The mouse ischemic hindlimb model is used widely for studying collateral artery growth (i.e., arteriogenesis) in response to increased shear stress. Nonetheless, precise measurements of regional shear stress changes along individual collateral arteries are lacking. Our goal is to develop and verify trans-illumination laser speckle flowmetry (LSF) for this purpose. Studies of defibrinated bovine blood flow through tubes embedded in tissue-mimicking phantoms indicate that trans-illumination LSF better maintains sensitivity with an increasing tissue depth when compared to epi-illumination, with an ∼50% reduction in the exponential decay of the speckle velocity signal. Applying trans-illuminated LSF to the gracilis muscle collateral artery network in vivo yields both improved sensitivity and reduced noise when compared to epi-illumination. Trans-illuminated LSF images reveal regional differences in collateral artery blood velocity after femoral artery ligation and are used to measure an ∼2-fold increase in the shear stress at the entrance regions to the muscle. We believe these represent the first direct measurements of regional shear stress changes in individual mouse collateral arteries. The ability to capture deeper vascular signals using a trans-illumination configuration for LSF may expand the current applications for LSF, which could have bearing on determining how shear stress magnitude and direction regulate arteriogenesis.

  20. Vasoactive enzymes and blood flow responses to passive and active exercise in peripheral arterial disease

    DEFF Research Database (Denmark)

    Walker, Meegan A.; Høier, Birgitte; Walker, Philip J.;

    2016-01-01

    Background: Peripheral arterial disease (PAD) is characterised by impaired leg blood flow, which contributes to claudication and reduced exercise capacity. This study investigated to what extent vasoactive enzymes might contribute to altered blood flow in PAD (Fontaine stage II). Methods: We...... compared femoral artery blood flow during reactive hyperaemia, leg-extension exercise and passive leg movement, and determined the level of vasoactive enzymes in skeletal muscle samples from the vastus lateralis in PAD (n = 10, 68.5 ± 6.5 years) and healthy controls (CON, n = 9, 62.1 ± 12.3 years). Leg...... than CON (1.04 ± 0.19 vs 0.50 ± 0.06 AU, P = 0.02), with no differences for other enzymes. Leg blood flow during exercise was correlated with prostacyclin synthase (P = 0.001). Conclusion: Elevated NADPH oxidase indicates that oxidative stress may be a primary cause of low nitric oxide availability...

  1. A theoretical computerized study for the electrical conductivity of arterial pulsatile blood flow by an elastic tube model.

    Science.gov (United States)

    Shen, Hua; Zhu, Yong; Qin, Kai-Rong

    2016-12-01

    The electrical conductivity of pulsatile blood flow in arteries is an important factor for the application of the electrical impedance measurement system in clinical settings. The electrical conductivity of pulsatile blood flow depends not only on blood-flow-induced red blood cell (RBC) orientation and deformation but also on artery wall motion. Numerous studies have investigated the conductivity of pulsatile blood based on a rigid tube model, in which the effects of wall motion on blood conductivity are not considered. In this study, integrating Ling and Atabek's local flow theory and Maxwell-Fricke theory, we develop an elastic tube model to explore the effects of wall motion as well as blood flow velocity on blood conductivity. The simulation results suggest that wall motion, rather than blood flow velocity, is the primary factor that affects the conductivity of flowing blood in arteries.

  2. A comparison of the pH of arterial blood with arterialised blood from the ear-lobe with astrup's micro glasselectrode

    NARCIS (Netherlands)

    Maas, A.H.J.; Heijst, A.N.P. van

    1961-01-01

    The pH of arterial blood and the blood from an arterialised ear-lobe are compared. The small difference (± 0.002 pH) is not important in studying the changes of the acid-base balance. It is concluded that blood obtained by puncture of the arterialised earlobe is a good substitute for blood obtained

  3. Blood Flow Imaging in Maternal and Fetal Arteries and Veins

    Science.gov (United States)

    Ricci, S.; Urban, G.; Vergani, P.; Paidas, M. J.; Tortoli, P.

    Maternal and fetal blood circulation has been investigated for nearly a decade through ultrasound (US) techniques. Evaluation of the spectrogram related to a single sample volume has been proven valuable for the assessment of fetal well-being and for prediction of pregnancy complications. In this work, an alternative technique, called Multigate Spectral Doppler Analysis (MSDA), is proposed. In this approach, 128 sample volumes aligned along the same scan line are simultaneously investigated to detect the blood velocity profile with high resolution. Profiles obtained through MSDA reveal features not detectable with the standard US technique, thus representing a more accurate flow signature. Some preliminary illustrative results are reported here.

  4. Blood glucose control using an artificial pancreas reduces the workload of ICU nurses.

    Science.gov (United States)

    Mibu, Kiyo; Yatabe, Tomoaki; Hanazaki, Kazuhiro

    2012-03-01

    Blood glucose management is one of the important therapies in the intensive care unit (ICU). However, blood glucose management using the sliding-scale method increases the workload of ICU nurses. An artificial pancreas, STG-22, has been developed to continuously monitor blood glucose levels and to maintain them at appropriate levels. In this study, we examined the hypothesis that compared to conventional methods, blood glucose management using the STG-22 reduces the workload of ICU nurses and has a positive impact on awareness regarding the management of blood glucose. This study included 45 patients who underwent elective surgery and were treated at the ICU postoperatively. The patients were separated into the following two groups: (1) blood glucose was maintained using the STG-22 (AP group) and (2) blood glucose was maintained using the sliding-scale method (SS group). In addition, a questionnaire was developed for an awareness survey of ICU nurses (N = 20). The frequency of blood sampling and number of double checks were significantly lower in the AP group (1.3 ± 1.4 vs. 8.9 ± 8.1 times/admission, P blood glucose.

  5. Hemoglobin, hematocrit, and changes in cerebral blood flow : The Second Manifestations of ARTerial disease-Magnetic Resonance study

    NARCIS (Netherlands)

    van der Veen, Pieternella H.; Muller, Majon; Vincken, Koen L.; Westerink, Jan; Mali, Willem P. T. M.; van der Graaf, Yolanda; Geerlings, Mirjam I.; Doevendans, PAFM

    2015-01-01

    Hemoglobin and hematocrit are important determinants of blood viscosity and arterial oxygen content and may therefore influence cerebral blood flow (CBF). We examined cross-sectional and prospective associations of hemoglobin and hematocrit with CBF in 569 patients with manifest arterial disease (me

  6. The phosphodiesterase 3 inhibitor cilostazol dilates large cerebral arteries in humans without affecting regional cerebral blood flow

    DEFF Research Database (Denmark)

    Birk, Steffen; Kruuse, Christina Rostrup; Petersen, Kenneth A;

    2004-01-01

    in the middle cerebral arteries (VMCA) was measured with transcranial Doppler, and the superficial temporal and radial arteries diameters were measured with ultrasonography. During the 4-hour observation period, there was no effect on systolic blood pressure (P = 0.28), but diastolic blood pressure decreased...

  7. Observation of flow variation in capillaries of artificial blood vessel by producing microbubble aggregations.

    Science.gov (United States)

    Masuda, Kohji; Shigehara, Nobuhiko; Koda, Ren; Watarai, Nobuyuki; Ikeda, Seiichi; Arai, Fumihito; Miyamoto, Yoshitaka; Chiba, Toshio

    2012-01-01

    Microbubbles form their aggregations between the neighboring microbubbles by the effect of secondary Bjerknes force under ultrasound exposure. However, because of the difficulty to reproduce a capillary-mimicking artificial blood vessel, the behavior of aggregations in a capillary has not been predicted. Thus we prepared artificial blood vessels including a capillary model, which was made of poly(vinyl alcohol) (PVA) by grayscale lithography method, with minimum diameter of the path of 0.5 mm. By using this model we investigated the possibility of artificial embolization, where the microbubble aggregations might block entire vessels not to penetrate flow in downstream. Confirming that the sizes of flown aggregation were greater than the section area of the minimum path in the capillary model, we investigated the probability of path block in it. As the results we confirmed the probability increased in proportion to sound pressure and inversely to flow velocity. We are going to investigate with more kinds of parameters to enhance the possibility of artificial embolization.

  8. Synthesis and biological screening by novel hybrid fluorocarbon hydrocarbon compounds for use as artificial blood substitutes

    Science.gov (United States)

    Moacanin, J.; Scherer, K.; Toronto, A.; Lawson, D.; Terranova, T.; Yavrouian, A.; Astle, L.; Harvey, S.; Kaaelble, D. H.

    1979-01-01

    A series of hybrid fluorochemicals of general structure R(1)R(2)R(3)CR(4) was prepared where the R(i)'s (i=1,2,3) is a saturated fluoroalkyl group of formula C sub N F sub 2n+1, and R(4) is an alkyl group C sub n H sub 2n+1 or a related moiety containing amino, ether, or ester functions but no CF bonds. Compounds of this class containing approximately eight to twenty carbons total have physical properties suitable for use as the oxygen carrying phase of fluorochemical emulsion artificial blood. The chemical synthesis, and physical and biological testing of pure single isomers of the proposed artificial blood candidate compounds are included. Significant results are given.

  9. Non-Newtonian effects of blood on LDL transport inside the arterial lumen and across multi-layered arterial wall with and without stenosis

    Science.gov (United States)

    Deyranlou, Amin; Niazmand, Hamid; Sadeghi, Mahmood-Reza; Mesri, Yaser

    2016-06-01

    Blood non-Newtonian behavior on low-density lipoproteins (LDL) accumulation is analyzed numerically, while fluid-multilayered arteries are adopted for nonstenotic and 30%-60% symmetrical stenosed models. Present model considers non-Newtonian effects inside the lumen and within arterial layers simultaneously, which has not been examined in previous studies. Navier-Stokes equations are solved along with the mass transport convection-diffusion equations and Darcy’s model for species transport inside the luminal flow and across wall layers, respectively. Carreau model for the luminal flow and the modified Darcy equation for the power-law fluid within arterial layers are employed to model blood rheological characteristics, appropriately. Results indicate that in large arteries with relatively high Reynolds number Newtonian model estimates LDL concentration patterns well enough, however, this model seriously incompetent for regions with low WSS. Moreover, Newtonian model for plasma underestimates LDL concentration especially on luminal surface and across arterial wall. Therefore, applying non-Newtonian model seems essential for reaching to a more accurate estimation of LDL distribution in the artery. Finally, blood flow inside constricted arteries demonstrates that LDL concentration patterns along the stenoses inside the luminal flow and across arterial layers are strongly influenced as compared to the nonstenotic arteries. Additionally, among four stenosis severity grades, 40% stenosis is prone to more LDL accumulation along the post-stenotic regions.

  10. Coupling between arterial and venous cerebral blood flow during postural change

    DEFF Research Database (Denmark)

    Ogoh, Shigehiko; Washio, Takuro; Sasaki, Hiroyuki

    2016-01-01

    carotid artery (ICA) and IJV blood flow decreased (P=0.004 and P=0.002), while vertebral artery (VA) flow did not change (P=0.348) and VV flow increased (P=0.024). In both supine and seated positions the ICA response to manipulation of end-tidal CO2 tension was reflected in IJV (r=0.645 and r=0.790, P... circulation, this study addressed both arterial and venous flow responses in the "anterior" and "posterior" parts of the brain when 9 healthy subjects (5 men) were seated and flow was manipulated by hyperventilation and inhalation of 6% carbon dioxide (CO2). From a supine to a seated position, both internal...... blood flow (r=0.649, P=0.004) and the two flows were coupled during manipulation of the end-tidal CO2 tension (supine, r=0.551, P=0.004; seated, r=0.612, P

  11. The role of increased pulmonary blood flow in pulmonary arterial hypertension

    NARCIS (Netherlands)

    van Albada, ME; Schoemaker, RG; Kemna, MS; Cromme - Dijkhuis, A; van Veghel, R; Berger, RMF

    2005-01-01

    Chronic increased pulmonary blood flow is considered a pre-requisite for the induction of advanced vascular lesions in pulmonary arterial hypertension in congenital heart defects. The aim of the present study was to characterise the effects of increased pulmonary flow induced by an aortocaval shunt

  12. Proprioceptive Neuromuscular Facilitation Flexibility Techniques: Acute Effects on Arterial Blood Pressure.

    Science.gov (United States)

    Cornelius, William L.; Craft-Hamm, Kelley

    1988-01-01

    The effects of stretching techniques on arterial blood pressure (ABP) were studied in three groups of 20 men each. Each group performed one of three proprioceptive neuromuscular facilitation (PNF) techniques. Results are presented. The study indicates that the benefits of stretching may outweigh the risk of elevated ABP. (JL)

  13. Two analytical solutions for a model of pulsed arterial spin labeling with randomized blood arrival times

    Science.gov (United States)

    Hrabe, J.; Lewis, D. P.

    2004-03-01

    A fairly general theoretical model for pulsed arterial spin labeling perfusion methods has been available for some time but analytical solutions were derived for only a small number of arterial blood input functions. These mostly assumed a sudden and simultaneous arrival of the tagged blood into the imaged region. More general cases had to be handled numerically. We present analytical solutions for two more realistic arterial input functions. They both allow the arrival times of the molecules of tagged arterial blood to be statistically distributed. We consider cases of (1) a uniform distribution on a finite time interval and (2) a normal distribution characterized by its mean and standard deviation. These models are physiologically meaningful because the statistical nature of the arrival times reflects the distribution of velocities and path lengths that the blood water molecules undertake from the tagging region to the imaged region. The model parameters can be estimated from the measured dependency of the perfusion signal on the tag inversion time.

  14. Niflumic Acid Attenuated Pulmonary Artery Tone and Vascular Structural Remodeling of Pulmonary Arterial Hypertension Induced by High Pulmonary Blood Flow In Vivo.

    Science.gov (United States)

    Wang, Kai; Ma, Jianfa; Pang, Yusheng; Lao, Jinquan; Pan, Xuanren; Tang, Qiaoyun; Zhang, Feng; Su, Danyan; Qin, Suyuan; Shrestha, Arnav Prasad

    2015-10-01

    Calcium-activated chloride channels (CaCCs) play a vital role in regulating pulmonary artery tone during pulmonary arterial hypertension (PAH) induced by high blood flow. The role of CaCCs inhibitor niflumic acid (NFA) in vivo during this process requires further investigation. We established the PAH model by abdominal shunt surgery and treated with NFA in vivo. Fifty rats were randomly divided into normal, sham, shunt, NFA group 1 (0.2 mg/kg), and NFA group 2 (0.4 mg/kg). Pathological changes, right ventricle hypertrophy index, arterial wall area/vessel area, and arterial wall thickness/vessel external diameter were analyzed. Then contraction reactions of pulmonary arteries were measured. Finally, the electrophysiological characteristics of pulmonary arterial smooth muscle cells were investigated using patch-clamp technology. After 11 weeks of shunting, PAH developed, accompanied with increased right ventricle hypertrophy index, arterial wall area/vessel area, and arterial wall thickness/vessel external diameter. In the NFA treatment groups, the pressure and pathological changes were alleviated. The pulmonary artery tone in the shunt group increased, whereas it decreased after NFA treatment. The current density of CaCC was higher in the shunt group, and it was decreased in the NFA treatment groups. In conclusion, NFA attenuated pulmonary artery tone and structural remodeling in PAH induced by high pulmonary blood flow in vivo. CaCCs were involved and the augmented current density was alleviated by NFA treatment.

  15. The effects of epinine on arterial blood pressure and regional vascular resistances in anesthetized rats.

    Science.gov (United States)

    Martínez-Mir, I; Palop, V; Morales-Olivas, F J; Estañ, L; Rubio, E

    1998-07-01

    1. We carried out experiments in anesthetized rats to study the hemodynamic effects of intravenous injections of epinine. 2. Epinine (1-320 micrograms/kg) produced a biphasic effect on mean arterial blood pressure (n = 30). At doses lower than 40 micrograms/kg, arterial blood pressure decreased (by as much as 21.5 +/- 3.4%), though at higher doses it increased dose dependently (by as much as 73.2 +/- 14.5%). Epinine also produced bradicardia in a dose-dependent manner (by as much as 26.4 +/- 4.9%). Sulpiride (100 micrograms/kg) suppressed the hypotensive effect of epinine but did not change the hypertensive effect. In the presence of prazosin (1,000 micrograms/kg), arterial blood pressure remained significantly decreased at all doses of epinine. Neither sulpiride nor prazosin changed the bradycardic effect of epinine. 3. Prazosin produced a significant decrease in renal vascular resistance. Epinine (5 micrograms/kg) after prazosin reverted the effects of prazosin in renal vascular resistance, without any significant modification in the renal blood flows. However, 20 micrograms/kg epinine increased the renal vascular resistances and, moreover, produced a significant decrease in the blood flows of both kidneys. Neither prazosin nor epinine produced modifications in the intestinal vascular bed. 4. Although epinine possesses significant dopamine and alpha-adrenergic activities that are involved in the biphasic effect of the agent on mean arterial blood pressure in anesthetized rats, in the presence of prazosin, it is not possible to manifest dopaminergic activity involved in the increase in renal or mesenteric blood flow; this may be due to the low tone of the vascular wall induced by the alpha-adrenergic antagonist, though an alpha 2-activity cannot be discarded.

  16. Phytoestrogen genistein decreases contractile response of aortic artery in vitro and arterial blood pressure in vivo

    Institute of Scientific and Technical Information of China (English)

    Hong-fang LI; Long-de WANG; Song-yi QU

    2004-01-01

    AIM: To determine the mechanisms of effects of phytoestrogen genistein on the contracted rabbit aortic arteries in vitro, and observe the effect of genistein and 17-β estradiol on mean arterial pressure (MAP) in ovariectomized (OVX) rats. METHODS: (1) Strips of rabbit aortic smooth muscle were suspended in organ baths containing Kreb's solution, and then isometric tension was measured. (2) Female mature Wistar rats underwent a bilateral ovariectomy (OVX). Sham-operated rats (SHAM) were used as controls. After administration of genistein (0.4(1) Similar to 17-β estradiol, genistein could dose-dependently relax 40 mmol/L KCl-precontracted arterial strips.Incubation with Nω-L-nitro-arginine (L-NNA), methylene blue (MB), indomethacin, propranolol or endothelium removal did not affect relaxation induced by genistein. In calcium-free solution containing 0.01mmol/L egtazic acid (EGTA), genistein inhibited not only the first phase contraction induced by noradrenaline (NA), but also the second contraction induced by CaCl2. In addition, genistein could reduce the contractile responses of NA, KCl and CaCl2,and shift their cumulative concentration-response curves rightward. (2) MAP in OVX rats was significantly higher compared with that of SHAM rats. However, after chronically treatment with genistein or 17-β estradiol for 21 d the baseline MAP in OVX rats was reduced significantly. CONCLUSIONS: (1) The vasodilator effect of genistein in vitro is endothelium independent and not related to the nitric oxide, its mechanisms being probably due to inhibition of Ca2+ influx through calcium channels in a noncompetitive manner and Ca2+ release from intracellular store induced by NA. (2) Administration of genistein or 17-β estradiol can chronically decrease MAP in OVX rats.

  17. Instability of the middle cerebral artery blood flow in response to CO2.

    Directory of Open Access Journals (Sweden)

    Rosemary E Regan

    Full Text Available BACKGROUND: The middle cerebral artery supplies long end-artery branches to perfuse the deep white matter and shorter peripheral branches to perfuse cortical and subcortical tissues. A generalized vasodilatory stimulus such as carbon dioxide not only results in an increase in flow to these various tissue beds but also redistribution among them. We employed a fast step increase in carbon dioxide to detect the dynamics of the cerebral blood flow response. METHODOLOGY/PRINCIPAL FINDINGS: The study was approved by the Research Ethics Board of the University Health Network at the University of Toronto. We used transcranial ultrasound to measure the time course of middle cerebral artery blood flow velocity in 28 healthy adults. Normoxic, isoxic step increases in arterial carbon dioxide tension of 10 mmHg from both hypocapnic and normocapnic baselines were produced using a new prospective targeting system that enabled a more rapid step change than has been previously achievable. In most of the 28 subjects the responses at both carbon dioxide ranges were characterised by more complex responses than a single exponential rise. Most responses were characterised by a fast initial response which then declined rapidly to a nadir, followed by a slower secondary response, with some showing oscillations before stabilising. CONCLUSIONS/SIGNIFICANCE: A rapid step increase in carbon dioxide tension is capable of inducing instability in the cerebral blood flow control system. These dynamic aspects of the cerebral blood flow responses to rapid changes in carbon dioxide must be taken into account when using transcranial blood flow velocity in a single artery segment to measure cerebrovascular reactivity.

  18. Roles of Arterial Stiffness and Blood Pressure in Hypertension-Associated Cognitive Decline in Healthy Adults.

    Science.gov (United States)

    Hajjar, Ihab; Goldstein, Felicia C; Martin, Greg S; Quyyumi, Arshed A

    2016-01-01

    Although there is strong evidence that hypertension leads to cognitive decline, especially in the executive domain, the relationship between blood pressure and cognition has been conflicted. Hypertension is characterized by blood pressure elevation and increased arterial stiffness. We aimed at investigating whether arterial stiffness would be superior to blood pressure in predicting cognitive decline and explaining the hypertension-executive decline association. A randomly selected asymptomatic population (n=591, age=49.2 years, 70% women, 27% black, and education=18 years) underwent annual vascular and cognitive assessments. Cognition was assessed using computerized versions commonly used cognitive tests, and principal component analysis was used for deriving cognitive scores for executive function, memory, and working memory. Arterial stiffness was measured by carotid-femoral pulse wave velocity (PWV). Higher PWV, but not blood pressure, was associated with a steeper decline in executive (P=0.0002), memory (P=0.05), and working memory (P=0.02) scores after adjusting for demographics, education, and baseline cognitive performance. This remained true after adjusting for hypertension. Hypertension was associated with greater decline in executive score (P=0.0029) and those with combined hypertension and elevated PWV (>7 m/s) had the greatest decline in executive score (P value hypertension×PWV=0.02). PWV explained the association between hypertension and executive function (P value for hypertension=0.0029 versus 0.24 when adjusting for PWV). In healthy adults, increased arterial stiffness is superior to blood pressure in predicting cognitive decline in all domains and in explaining the hypertension-executive function association. Arterial stiffness, especially in hypertension, may be a target in the prevention of cognitive decline.

  19. Coupling between arterial and venous cerebral blood flow during postural change.

    Science.gov (United States)

    Ogoh, Shigehiko; Washio, Takuro; Sasaki, Hiroyuki; Petersen, Lonnie G; Secher, Niels H; Sato, Kohei

    2016-12-01

    In supine humans the main drainage from the brain is through the internal jugular vein (IJV), but the vertebral veins (VV) become important during orthostatic stress because the IJV is partially collapsed. To identify the effect of this shift in venous drainage from the brain on the cerebral circulation, this study addressed both arterial and venous flow responses in the "anterior" and "posterior" parts of the brain when nine healthy subjects (5 men) were seated and flow was manipulated by hyperventilation and inhalation of 6% carbon dioxide (CO2). From a supine to a seated position, both internal carotid artery (ICA) and IJV blood flow decreased (P = 0.004 and P = 0.002), while vertebral artery (VA) flow did not change (P = 0.348) and VV flow increased (P = 0.024). In both supine and seated positions the ICA response to manipulation of end-tidal CO2 tension was reflected in IJV (r = 0.645 and r = 0.790, P blood flow (r = 0.771 and r = 0.828, P blood flow did not affect venous outflow, but the decrease in IJV blood flow was associated with the increase in VV blood flow (r = 0.479, P = 0.044). In addition, the increase in VV blood flow when seated was reflected in VA blood flow (r = 0.649, P = 0.004), and the two flows were coupled during manipulation of the end-tidal CO2 tension (supine, r = 0.551, P = 0.004; seated, r = 0.612, P blood flow when seated and that VV may influence VA blood flow.

  20. Unilateral fetal-type circle of Willis anatomy causes right-left asymmetry in cerebral blood flow with pseudo-continuous arterial spin labeling: A limitation of arterial spin labeling-based cerebral blood flow measurements?

    Science.gov (United States)

    Barkeij Wolf, Jurriaan Jh; Foster-Dingley, Jessica C; Moonen, Justine Ef; van Osch, Matthias Jp; de Craen, Anton Jm; de Ruijter, Wouter; van der Mast, Roos C; van der Grond, Jeroen

    2016-09-01

    The accuracy of cerebral blood flow measurements using pseudo-continuous arterial spin labeling can be affected by vascular factors other than cerebral blood flow, such as flow velocity and arterial transit time. We aimed to elucidate the effects of common variations in vascular anatomy of the circle of Willis on pseudo-continuous arterial spin labeling signal. In addition, we investigated whether possible differences in pseudo-continuous arterial spin labeling signal could be mediated by differences in flow velocities. Two hundred and three elderly participants underwent magnetic resonance angiography of the circle of Willis and pseudo-continuous arterial spin labeling scans. Mean pseudo-continuous arterial spin labeling-cerebral blood flow signal was calculated for the gray matter of the main cerebral flow territories. Mean cerebellar gray matter pseudo-continuous arterial spin labeling-cerebral blood flow was significantly lower in subjects having a posterior fetal circle of Willis variant with an absent P1 segment. The posterior fetal circle of Willis variants also showed a significantly higher pseudo-continuous arterial spin labeling-cerebral blood flow signal in the ipsilateral flow territory of the posterior cerebral artery. Flow velocity in the basilar artery was significantly lower in these posterior fetal circle of Willis variants. This study indicates that pseudo-continuous arterial spin labeling measurements underestimate cerebral blood flow in the posterior flow territories and cerebellum of subjects with a highly prevalent variation in circle of Willis morphology. Additionally, our data suggest that this effect is mediated by concomitant differences in flow velocity between the supplying arteries.

  1. Mathematical modelling of blood flow through a tapered overlapping stenosed artery with variable viscosity

    CERN Document Server

    Shit, G C; Sinha, A

    2012-01-01

    This paper presents a theoretical study of blood flow through a tapered and overlapping stenosed artery under the action of an externally applied magnetic field. The fluid (blood) medium is assumed to be porous in nature. The variable viscosity of blood depending on hematocrit (percentage volume of erythrocytes) is taken into account in order to improve resemblance to the real situation. The governing equation for laminar, incompressible and Newtonian fluid subject to the boundary conditions is solved by using a well known Frobenius method. The analytical expressions for velocity component, volumetric flow rate, wall shear stress and pressure gradient are obtained. The numerical values are extracted from these analytical expressions and are presented graphically. It is observed that the influence of hematocrit, magnetic field and the shape of artery have important impact on the velocity profile, pressure gradient and wall shear stress. Moreover, the effect of primary stenosis on the secondary one has been sig...

  2. Evaluation of a novel artificial pancreas: closed loop glycemic control system with continuous blood glucose monitoring.

    Science.gov (United States)

    Tsukamoto, Yuuki; Kinoshita, Yoshihiko; Kitagawa, Hiroyuki; Munekage, Masaya; Munekage, Eri; Takezaki, Yuka; Yatabe, Tomoaki; Yamashita, Koichi; Yamazaki, Rie; Okabayashi, Takehiro; Tarumi, Masatoshi; Kobayashi, Masaki; Mishina, Suguru; Hanazaki, Kazuhiro

    2013-04-01

    A closed-loop glycemic control system using an artificial pancreas has been applied with many clinical benefits in Japan since 1987. To update this system incorporating user-friendly features, we developed a novel artificial pancreas (STG-55). The purpose of this study was to evaluate STG-55 for device usability, performance of blood glucose measurement, glycemic control characteristics in vivo in animal experiments, and evaluate its clinical feasibility. There are several features for usability improvement based on the design concepts, such as compactness, display monitor, batteries, guidance function, and reduction of the preparation time. All animal study data were compared with a clinically available artificial pancreas system in Japan (control device: STG-22). We examined correlations of both blood glucose levels between two groups (STG-55 vs. control) using Clarke's error grid analysis, and also compared mean glucose infusion rate (GIR) during glucose clamp. The results showed strong correlation in blood glucose concentrations (Pearson's product-moment correlation coefficient: 0.97; n = 1636). Clarke's error grid analysis showed that 98.4% of the data fell in Zones A and B, which represent clinically accurate or benign errors, respectively. The difference in mean GIRs was less than 0.2 mg/kg/min, which was considered not significant. Clinical feasibility study demonstrated sufficient glycemic control maintaining target glucose range between 80 and 110 (mg/dL), and between 140 and 160 without any hypoglycemia. In conclusion, STG-55 was a clinically acceptable artificial pancreas with improved interface and usability. A closed-loop glycemic control system with STG-55 would be a useful tool for surgical and critical patients in intensive care units, as well as diabetic patients.

  3. Cell surface alterations during blood-storage characterized by artificial aggregation of washed red blood cells.

    Science.gov (United States)

    Hessel, E; Lerche, D

    1985-01-01

    Aggregation measurement of washed human erythrocytes (RBC) were carried out in a NaCl-PBS solution under laminar shear conditions. Artificial aggregation of fresh and stored erythrocytes was caused by decreased pH and reduced ionic strength and characterized by collision efficiency alpha. Generally, the collision efficiency alpha of stored erythrocytes rises with the increased storage time. Such an aggregation technique might be useful to detect and quantify changes of the membrane and/or the surface structure due to aging and/or storage.

  4. Energy harvesting from arterial blood pressure for powering embedded brain sensors

    Science.gov (United States)

    Nanda, Aditya; Karami, M. Amin

    2016-04-01

    This paper investigates energy harvesting from arterial blood pressure via the piezoelectric effect by using a novel streaked cylinder geometry for the purpose of powering embedded micro-sensors in the brain. Initially, we look at the energy harvested by a piezoelectric cylinder placed inside an artery acted upon by blood pressure. Such an arrangement would be tantamount to constructing a stent out of piezoelectric materials. A stent is a cylinder placed in veins and arteries to prevent obstruction in blood flow. The governing equations of a conductor coated piezoelectric cylinder are obtained using Hamilton's principle. Pressure acting in arteries is radially directed and this is used to simplify the modal analysis and obtain the transfer function relating pressure to the induced voltage across the surface of the harvester. The power harvested by the cylindrical harvester is obtained for different shunt resistances. Radially directed pressure occurs elsewhere and we also look at harvesting energy from oil flow in pipelines. Although the energy harvested by the cylindrical energy harvester is significant at resonance, the natural frequency of the system is found to be very high. To decrease the natural frequency, we propose a novel streaked stent design by cutting it along the length, transforming it to a curved plate and decreasing the natural frequency. The governing equations corresponding to the new geometry are derived using Hamilton's principle and modal analysis is used to obtain the transfer function.

  5. Use of paravascular admittance waveforms to monitor relative change in arterial blood pressure

    Science.gov (United States)

    Zielinski, Todd M.; Hettrick, Doug; Cho, Yong

    2010-04-01

    Non-invasive methods to monitor ambulatory blood pressure often have limitations that can affect measurement accuracy and patient adherence [1]. Minimally invasive measurement of a relative blood pressure surrogate with an implantable device may provide a useful chronic diagnostic and monitoring tool. We assessed a technique that uses electrocardiogram and paravascular admittance waveform morphology analysis to one, measure a time duration (vascular tone index, VTI in milliseconds) change from the electrocardiogram R-wave to admittance waveform peak and two, measure the admittance waveform minimum, maximum and magnitude as indicators of change in arterial compliance/distensibility or pulse pressure secondary to change in afterload. Methods: Five anesthetized domestic pigs (32 ± 4.2 kg) were used to study the effects of phenylephrine (1-5 ug/kg/min) on femoral artery pressure and admittance waveform morphology measured with a quadrapolar electrode array catheter placed next to the femoral artery to assess the relative change in arterial compliance due to change in peripheral vascular tone. Results: Statistical difference was observed (p blood pressure may be suitable for implantable devices to detect progression of cardiovascular disease such as hypertension.

  6. Comparison of how well conscious cats tolerate blood pressure measurement from the radial and coccygeal arteries.

    Science.gov (United States)

    Cannon, Martha J; Brett, Jo

    2012-12-01

    Hypertension is a common condition of older cats and acquiring clinically relevant and repeatable blood pressure (BP) measurements in conscious cats is important in its diagnosis and management. The most common sites for indirect BP measurement in the cat are the radial artery (RA) and the coccygeal artery (CA) but, to date, there are no published data comparing how conscious cats tolerate BP measurements from these sites. A high-definition oscillometric BP monitor was used to measure BP in 30 cats admitted to a cat-only veterinary clinic for reasons other than hypertension. Systolic arterial pressure (SAP), mean arterial pressure (MAP) and diastolic arterial pressure (DAP) were measured using the RA and CA, alternating which site was used first. The number of failed attempts and total time to achieve six measurements was recorded. Measurement of BP using the CA was better tolerated than the RA, resulting in fewer failures and shorter total time required. SAP measurements were slightly higher from the CA compared with the RA, irrespective of which site was used first. There were no significant differences in MAP and DAP. The coccygeal artery appears to be the more appropriate site to use when measuring BP in conscious cats using this oscillometric machine. Further studies are required using alternative BP monitors, including Doppler machines, to establish whether this is a consistent finding. When measuring BP in cats the site used should be recorded and the same site used for all subsequent measurements from the same cat.

  7. The effects of fenoldopam on coronary conduit blood flow after coronary artery bypass graft surgery.

    LENUS (Irish Health Repository)

    Halpenny, M

    2012-02-03

    OBJECTIVE: To quantify the effects of fenoldopam, 0.1 microg\\/kg\\/min, on left internal mammary artery (LIMA) and saphenous vein blood flow after coronary anastomosis. DESIGN: Prospective, randomized, double-blind, placebo-controlled trial. SETTING: University teaching hospital, single institution. PARTICIPANTS: Thirty-one American Society of Anesthesiologists III patients undergoing elective coronary revascularization. INTERVENTIONS: A perivascular ultrasonic flow probe (Linton Instrumentation, Norfolk, UK) was placed around the LIMA and saphenous vein graft after coronary anastomosis. MEASUREMENTS AND MAIN RESULTS: Immediately before and at 5-minute intervals for 15 minutes after starting the infusion, blood flow was measured in the LIMA and one saphenous vein graft using a transit time ultrasonic flow probe. Heart rate, blood pressure, and central venous pressure were documented at these time points. Administration of fenoldopam, 0.1 microg\\/kg\\/min, did not alter heart rate or blood pressure. A small, nonsignificant increase in LIMA blood flow occurred during the 15-minute study period (30 +\\/- 12 to 35 +\\/- 10 mL\\/min) in patients who received fenoldopam. No significant changes occurred in the placebo group. CONCLUSIONS: The findings indicate that fenoldopam, 0.1 microg\\/kg\\/min, did not influence coronary conduit blood flow to a clinically significant extent. The small increase in LIMA blood flow may be of greater importance in high-risk patients or in the prevention of coronary arterial spasm.

  8. Active Path Selection of Fluid Microcapsules in Artificial Blood Vessel by Acoustic Radiation Force

    Science.gov (United States)

    Masuda, Kohji; Muramatsu, Yusuke; Ueda, Sawami; Nakamoto, Ryusuke; Nakayashiki, Yusuke; Ishihara, Ken

    2009-07-01

    Micrometer-sized microcapsules collapse upon exposure to ultrasound. Use of this phenomenon for a drug delivery system (DDS), not only for local delivery of medication but also for gene therapy, should be possible. However, enhancing the efficiency of medication is limited because capsules in suspension diffuse in the human body after injection, since the motion of capsules in blood flow cannot be controlled. To control the behavior of microcapsules, acoustic radiation force was introduced. We detected local changes in microcapsule density by producing acoustic radiation force in an artificial blood vessel. Furthermore, we theoretically estimated the conditions required for active path selection of capsules at a bifurcation point in the artificial blood vessel. We observed the difference in capsule density at both in the bifurcation point and in alternative paths downstream of the bifurcation point for different acoustic radiation forces. Comparing the experimental results with those obtained theoretically, the conditions for active path selection were calculated from the acoustic radiation force and fluid resistance of the capsules. The possibility of controlling capsule flow towards a specific point in a blood vessel was demonstrated.

  9. Comparison of noninvasive blood pressure measurement techniques via the coccygeal artery in anesthetized cheetahs (Acinonyx jubatus).

    Science.gov (United States)

    Sadler, Ryan A; Hall, Natalie H; Kass, Philip H; Citino, Scott B

    2013-12-01

    Two indirect blood pressure measurement techniques, Doppler (DOP) sphygmomanometry and oscillometry, applied at the ventral coccygeal artery were compared with simultaneous direct blood pressure measurements at the dorsal pedal artery in 10 anesthetized, captive cheetahs (Acinonyx jubatus). The DOP method was moderately accurate, with relatively little bias (mean difference 3.8 mmHg) and 88.6% of the DOP systolic arterial pressure measurements being within 10 mmHg of the direct systolic arterial measurement. With the oscillometric (OM) method, 89.2% of the mean arterial pressure measurements were within 10 mmHg of the direct measurement and had the least bias (mean difference 2.3 mmHg), 80.7% of the systolic measurements were within 10 mmHg of the direct measurement and had the second least bias (mean difference 2.3 mmHg), and 59% of the diastolic measurements were within 10 mmHg of the direct measurement and had significant bias (mean difference 7.3 mmHg). However, DOP showed relatively poor precision (SD 11.2 mmHg) compared with OM systolic (SD 8.0 mmHg), diastolic (SD 8.6 mmHg), and mean (SD 5.7 mmHg). Both techniques showed a linear relationship with the direct technique measurements over a wide range of blood pressures. The DOP method tended to underestimate systolic measurements below 160 mmHg and overestimate systolic measurements above 160 mmHg. The OM method tended to underestimate mean pressures below 160 mm Hg, overestimate mean pressures above 160 mmHg, underestimate systolic pressures below 170 mmHg, overestimate systolic pressures above 170 mmHg, and underestimate diastolic pressures throughout the measured blood pressure range. Indirect blood pressure measurement using the ventral coccygeal artery, particularly when using an OM device for mean and systolic arterial pressure, may be useful in the clinical assessment of cheetahs when monitoring trends over time, but caution should be taken when interpreting individual values.

  10. Artificial reproduction of magnetic fields produced by a natural geomagnetic storm increases systolic blood pressure in rats

    Science.gov (United States)

    Martínez-Bretón, J. L.; Mendoza, B.; Miranda-Anaya, M.; Durán, P.; Flores-Chávez, P. L.

    2016-04-01

    The incidence of geomagnetic storms may be associated with changes in circulatory physiology. The way in which the natural variations of the geomagnetic field due to solar activity affects the blood pressure are poorly understood and require further study in controlled experimental designs in animal models. In the present study, we tested whether the systolic arterial pressure (AP) in adult rats is affected by simulated magnetic fields resembling the natural changes of a geomagnetic storm. We exposed adult rats to a linear magnetic profile that simulates the average changes associated to some well-known geomagnetic storm phases: the sudden commencement and principal phase. Magnetic stimulus was provided by a coil inductor and regulated by a microcontroller. The experiments were conducted in the electromagnetically isolated environment of a semi-anechoic chamber. After exposure, AP was determined with a non-invasive method through the pulse on the rat's tail. Animals were used as their own control. Our results indicate that there was no statistically significant effect in AP when the artificial profile was applied, neither in the sudden commencement nor in the principal phases. However, during the experimental period, a natural geomagnetic storm occurred, and we did observe statistically significant AP increase during the sudden commencement phase. Furthermore, when this storm phase was artificially replicated with a non-linear profile, we noticed a 7 to 9 % increase of the rats' AP in relation to a reference value. We suggested that the changes in the geomagnetic field associated with a geomagnetic storm in its first day could produce a measurable and reproducible physiological response in AP.

  11. Artificial reproduction of magnetic fields produced by a natural geomagnetic storm increases systolic blood pressure in rats

    Science.gov (United States)

    Martínez-Bretón, J. L.; Mendoza, B.; Miranda-Anaya, M.; Durán, P.; Flores-Chávez, P. L.

    2016-11-01

    The incidence of geomagnetic storms may be associated with changes in circulatory physiology. The way in which the natural variations of the geomagnetic field due to solar activity affects the blood pressure are poorly understood and require further study in controlled experimental designs in animal models. In the present study, we tested whether the systolic arterial pressure (AP) in adult rats is affected by simulated magnetic fields resembling the natural changes of a geomagnetic storm. We exposed adult rats to a linear magnetic profile that simulates the average changes associated to some well-known geomagnetic storm phases: the sudden commencement and principal phase. Magnetic stimulus was provided by a coil inductor and regulated by a microcontroller. The experiments were conducted in the electromagnetically isolated environment of a semi-anechoic chamber. After exposure, AP was determined with a non-invasive method through the pulse on the rat's tail. Animals were used as their own control. Our results indicate that there was no statistically significant effect in AP when the artificial profile was applied, neither in the sudden commencement nor in the principal phases. However, during the experimental period, a natural geomagnetic storm occurred, and we did observe statistically significant AP increase during the sudden commencement phase. Furthermore, when this storm phase was artificially replicated with a non-linear profile, we noticed a 7 to 9 % increase of the rats' AP in relation to a reference value. We suggested that the changes in the geomagnetic field associated with a geomagnetic storm in its first day could produce a measurable and reproducible physiological response in AP.

  12. Automated characterization of blood vessels as arteries and veins in retinal images.

    Science.gov (United States)

    Mirsharif, Qazaleh; Tajeripour, Farshad; Pourreza, Hamidreza

    2013-01-01

    In recent years researchers have found that alternations in arterial or venular tree of the retinal vasculature are associated with several public health problems such as diabetic retinopathy which is also the leading cause of blindness in the world. A prerequisite for automated assessment of subtle changes in arteries and veins, is to accurately separate those vessels from each other. This is a difficult task due to high similarity between arteries and veins in addition to variation of color and non-uniform illumination inter and intra retinal images. In this paper a novel structural and automated method is presented for artery/vein classification of blood vessels in retinal images. The proposed method consists of three main steps. In the first step, several image enhancement techniques are employed to improve the images. Then a specific feature extraction process is applied to separate major arteries from veins. Indeed, vessels are divided to smaller segments and feature extraction and vessel classification are applied to each small vessel segment instead of each vessel point. Finally, a post processing step is added to improve the results obtained from the previous step using structural characteristics of the retinal vascular network. In the last stage, vessel features at intersection and bifurcation points are processed for detection of arterial and venular sub trees. Ultimately vessel labels are revised by publishing the dominant label through each identified connected tree of arteries or veins. Evaluation of the proposed approach against two different datasets of retinal images including DRIVE database demonstrates the good performance and robustness of the method. The proposed method may be used for determination of arteriolar to venular diameter ratio in retinal images. Also the proposed method potentially allows for further investigation of labels of thinner arteries and veins which might be found by tracing them back to the major vessels.

  13. Progressive artificial endocrine pancreas: The era of novel perioperative blood glucose control for surgery.

    Science.gov (United States)

    Tsukamoto, Yuuki; Okabayashi, Takehiro; Hanazaki, Kazuhiro

    2011-10-01

    Strict glycemic control needs to be maintained in critically ill surgical patients to reduce the mortality and morbidity due to hyperglycemia and associated infection. However, conventional intensive insulin therapy (IIT), which consists of intermittent blood glucose measurement and manually controlled infusions of insulin, tends to induce hypoglycemia and glucose variability. Many randomized clinical trials have been conducted to improve the efficacy of IIT, although some of these were stopped owing to frequent hypoglycemia. In pursuing safe and strict glycemic control for critically ill surgical patients, we found that a closed-loop glycemic control system was able to maintain appropriate blood glucose levels without hypoglycemia in more than 400 clinical cases. Considering the need for the perioperative and intensive care environment, a well-established artificial pancreas was modified into a new closed-loop glycemic control system, called the progressive artificial pancreas. The new device is slim in shape and shows clinical compatibility with the conventional artificial pancreas. We herein review this new closed-loop glycemic control system and the expectations for its future application in critically ill surgical patients.

  14. Artificial blood circulatory and special Ultrasound Doppler probes for detecting and sizing gaseous embolism

    Directory of Open Access Journals (Sweden)

    Stark Philipp

    2016-09-01

    Full Text Available This paper presents a special designed artificial blood circulatory (ABC for studying gaseous embolism based on detection of gaseous emboli and their sizing using ultrasound (US spectral Doppler. Blood mimicking fluid (BMF was used in the circulatory to get valid results without using human blood. The additional necessary degassing circulatory shows a promising effect of decontaminating the BMF from air bubbles. This offers the base for detecting and sizing microemboli using special algorithms and finally leads to reliable calculations of dangerous embolism and its air volume. Standard US probes at an integrated tissue model and a new 8-MHz central catheter ultrasound (CCUS probe inside a superior vena cava model (SVCM are used and deliver the Doppler spectrogram as input for automatic emboli detection and further signal analysis. First results using the newly developed 8-MHz CCUS probe inside the SVCM and its Doppler spectrogram characteristics show promising results but need more detailed studies.

  15. Adiponectin Genotype, Blood Pressures, and Arterial Stiffness: The Cardiometabolic Risk in Chinese (CRC) Study.

    Science.gov (United States)

    Liang, Jun; Qiu, Qinqin; Gong, Ying; Liu, Xuekui; Dou, Lianjun; Zou, Caiyan; Wang, Yu; Qi, Lu

    2015-05-01

    The authors examined whether the adiponectin gene (ADIPOQ) variant was associated with blood pressure and arterial stiffness in Chinese adults. A genome-wide association study of the adiponectin variant rs864265 in the ADIPOQ gene was genotyped in a total of 2364 participants. After adjustment for sex, age, body mass index (BMI), fasting glucose, and lipids, participants carrying the T allele of rs864265 showed a greater increase in carotid-femoral pulse wave velocity (cfPWV) and systolic blood pressure (SBP). Further adjustment for blood pressure did not appreciably change the association with cfPWV. The authors found significant interactions between rs864265 and BMI, waist circumference, body fat percentage, and SBP in relation to cfPWV (P for interaction = .035, .001, .003, .013, respectively). The T allele of rs864265 was associated with high blood pressure and arterial stiffness. BMI, body fat percentage, waist circumference, and SBP might modify the effects of genetic polymorphism on arterial stiffness.

  16. Association of ABO Blood Types With Atherosclerosis Risk Factors and Number of Involved Coronary Arteries

    Directory of Open Access Journals (Sweden)

    Golmohammadi Ali

    2016-01-01

    Full Text Available Objective: Cardiovascular disease (CVD is a common cause of morbidity and mortality. The relationship between ABO blood groups and main risk factors of CVD is unknown. So this study was designed to investigate whether there is an association between ABO blood groups and cardiovascular risk factors in otherwise healthy people. Materials and Methods: In this cross-sectional study, risk factors for CVD were screened in 300 patients with coronary artery disease (CAD who were hospitalized in Madani hospital (biggest heart center in Tabriz in 2013-2014 and evaluated by a questionnaire that aimed to extract information about age, sex, smoking, blood group type, weight, height, blood pressure, diabetes mellitus and family history of CVD. Data were analyzed with SPSS 17. Results: Of the total selected 300 patients, 69.3% were male, 35.3% were smoker, 61% were hypertensive, 30.3% were diabetic mellitus, 31% had hyperlipidemia, 70.97% were obese and 17.3% had family history of CVD. The mean age was 62.06 ± 11.40 years. Blood groups O (28%, A (43.3%, B (19% and AB (7.3% were the most frequent ones, respectively. According to our results, we found that the rate of CAD in individuals with the blood group A was higher than the other blood groups. Regarding the risk factors, however, no significant difference was observed between the blood groups. Conclusion: A correlation was found between blood group A and the incidence of CAD and there was no significant difference between the blood groups and cardiovascular risk factors and number of involved coronary arteries.

  17. A pitfall in the measurement of arterial blood pressure in the ischaemic limb during elevation

    DEFF Research Database (Denmark)

    Bülow, J; Jelnes, Rolf

    1987-01-01

    kept at 10 mmHg during elevation. In these patients, the increase in vascular resistance was significantly less compared with the situation in which venous pressure was 0 mmHg during elevation. The arterial pressure still did not decrease. It is concluded that perfusion pressure in the ischaemic lower......In order to evaluate if elevation of the ischaemic limb above heart level is an alternative to the conventionally applied method with external counterpressure for estimation of skin perfusion pressure, femoral and popliteal artery pressures were measured directly in eight patients with occlusion...... of the superficial femoral artery. The measurements were done in the horizontal position and during elevation of the calf above heart level. During elevation relative blood flow, measured by arterio-venous oxygen saturation differences, decreased compared with the horizontal position. In contrast the popliteal...

  18. The mechanical properties of the systemic and pulmonary arteries of Python regius correlate with blood pressures.

    Science.gov (United States)

    van Soldt, Benjamin J; Danielsen, Carl Christian; Wang, Tobias

    2015-12-01

    Pythons are unique amongst snakes in having different pressures in the aortas and pulmonary arteries because of intraventricular pressure separation. In this study, we investigate whether this correlates with different blood vessel strength in the ball python Python regius. We excised segments from the left, right, and dorsal aortas, and from the two pulmonary arteries. These were subjected to tensile testing. We show that the aortic vessel wall is significantly stronger than the pulmonary artery wall in P. regius. Gross morphological characteristics (vessel wall thickness and correlated absolute amount of collagen content) are likely the most influential factors. Collagen fiber thickness and orientation are likely to have an effect, though the effect of collagen fiber type and cross-links between fibers will need further study.

  19. Increasing arterial blood pressure with norepinephrine does not improve microcirculatory blood flow: a prospective study

    NARCIS (Netherlands)

    A. Dubin; M.O. Pozo; C.A. Casabella; F.,Jr Pálizas; G. Murias; M.C. Moseinco; V.S. Kanoore Edul; F. Pálizas; E. Estenssoro; C. Ince

    2009-01-01

    Introduction Our goal was to assess the effects of titration of a norepinephrine infusion to increasing levels of mean arterial pressure (MAP) on sublingual microcirculation. Methods Twenty septic shock patients were prospectively studied in two teaching intensive care units. The patients were mecha

  20. Microalbuminuria associated with systolic blood pressure and arterial compliance in Chinese metabolic syndrome patients

    Institute of Scientific and Technical Information of China (English)

    LI Xin-li; XU Qiong; TONG Min; LU Xin-zheng; ZHANG Hai-feng; ZHOU Yan-li; CAO Ke-jiang; HUANG Jun

    2007-01-01

    Background There is significant evidence showing that microalbuminuria and arterial compliance are sensitive markers for early cardiovascular diseases. However, whether microalbuminuria is associated with reduced arterial compliance in Chinese metabolic syndrome (MS) patients remains unknown.Methods According to the definition of MS proposed by ATPⅢ in 2001, USA, subjects (n=362) were divided into three groups according to the number of risk factors: group 1 (control), group 2 (medium, < 3 risk factors) and group 3 (MS, ≥ 3 risk factors). Both large artery compliance (C1) and small artery compliance (C2) were measured with the CVProfilor DO-2020 Cardiovascular Profiling System, and microalbuminuria was evaluated with the ratio of albumin to urine creatinine.Results (1) As C1 and C2 levels elasticity decreased, albumin creatinine ratio (ACR) and the prevalence of microalbuminuria increased within those groups with MS risk factors. C1 and C2 were negatively correlated with the ranking of MS risk factors, ACR was positively correlated with the ranking of MS risk factors (all P<0.05). (2) Subjects were also categorized into a microalbuminuria group and a normal group, C1 and C2 in the microalbuminuria group were lower than in the normal group. (3) Multivariate regression analysis showed that increased systolic blood pressure (SBP) and reduced arterial compliance were the main risk factors for microalbuminuria in the MS group.Conclusions The risk of developing microalbuminuria was higher in the subjects with multiple metabolic abnormalities.Increased systolic blood pressure and reduced arterial compliance may be the main predictors for microalbuminuria in MS.

  1. The Rheology of Blood Flow in a Branched Arterial System.

    Science.gov (United States)

    Shibeshi, Shewaferaw S; Collins, William E

    2005-01-01

    Blood flow rheology is a complex phenomenon. Presently there is no universally agreed upon model to represent the viscous property of blood. However, under the general classification of non-Newtonian models that simulate blood behavior to different degrees of accuracy, there are many variants. The power law, Casson and Carreau models are popular non-Newtonian models and affect hemodynamics quantities under many conditions. In this study, the finite volume method is used to investigate hemodynamics predictions of each of the models. To implement the finite volume method, the computational fluid dynamics software Fluent 6.1 is used. In this numerical study the different hemorheological models are found to predict different results of hemodynamics variables which are known to impact the genesis of atherosclerosis and formation of thrombosis. The axial velocity magnitude percentage difference of up to 2 % and radial velocity difference up to 90 % is found at different sections of the T-junction geometry. The size of flow recirculation zones and their associated separation and reattachment point's locations differ for each model. The wall shear stress also experiences up to 12 % shift in the main tube. A velocity magnitude distribution of the grid cells shows that the Newtonian model is close dynamically to the Casson model while the power law model resembles the Carreau model. ZUSAMMENFASSUNG: Die Rheologie von Blutströmungen ist ein komplexes Phänomen. Gegenwärtig existiert kein allgemein akzeptiertes Modell, um die viskosen Eigenschaften von Blut wiederzugeben. Jedoch gibt es mehrere Varianten unter der allgemeinen Klassifikation von nicht-Newtonschen Modellen, die das Verhalten von Blut mit unterschiedlicher Genauigkeit simulieren. Die Potenzgesetz-, Casson und Carreau-Modelle sind beliebte nicht-New-tonsche Modelle und beeinflussen die hämodynamischen Eigenschaften in vielen Situationen. In dieser Studie wurde die finite Volumenmethode angewandt, um die h

  2. Correlation between penile cavernosal artery blood flow and retinal vascular findings in arteriogenic erectile dysfunction

    Directory of Open Access Journals (Sweden)

    Ahmed M Emarah

    2010-09-01

    Full Text Available Ahmed M Emarah1, Shawky M El-Haggar2, Ihab A Osman2, Abdel Wahab S Khafagy21Departments of Ophthalmology, 2Andrology and Sexology, Cairo University Hospital, EgyptObjectives: Arteriogenic erectile dysfunction (ED is a target organ disease of atherosclerosis, and therefore might be a predictor of systemic atherosclerosis. Being systemic, it might be possible to evaluate the extent of atherosclerosis from retinal vascular findings. We investigated the possible correlation between penile cavernosal artery blood flow and retinal vascular findings in patients with arteriogenic ED.Patients and methods: Sixty patients with ED were divided according to the peak systolic velocity (PSV in their penile cavernosal arteries into two groups; Group A included 30 patients with PSV less than 25 cm/sec, and Group B included 30 patients with PSV more than 35 cm/sec. Blood flow in the penile cavernosal artery was measured with color Doppler ultrasonography. All patients were assessed by ocular fundus examination under amydriatic conditions to evaluate retinal vascular atherosclerotic changes using Hyman’s classification.Results: Evidence of retinal vascular atherosclerotic changes was found in 19 patients (63.3% in Group A and in 10 patients (33.3% in Group B.Conclusions: Our study confirms the possibility of predicting penile arterial vascular status in patients with ED from their retinal vascular findings by using amydriatic simple, practical funduscopy.Keywords: erectile dysfunction, atherosclerosis, retinal vascular atherosclerosis

  3. A Novel Analytical Approach to Pulsatile Blood Flow in the Arterial Network.

    Science.gov (United States)

    Flores, Joaquín; Alastruey, Jordi; Corvera Poiré, Eugenia

    2016-10-01

    Haemodynamic simulations using one-dimensional (1-D) computational models exhibit many of the features of the systemic circulation under normal and diseased conditions. We propose a novel linear 1-D dynamical theory of blood flow in networks of flexible vessels that is based on a generalized Darcy's model and for which a full analytical solution exists in frequency domain. We assess the accuracy of this formulation in a series of benchmark test cases for which computational 1-D and 3-D solutions are available. Accordingly, we calculate blood flow and pressure waves, and velocity profiles in the human common carotid artery, upper thoracic aorta, aortic bifurcation, and a 20-artery model of the aorta and its larger branches. Our analytical solution is in good agreement with the available solutions and reproduces the main features of pulse waveforms in networks of large arteries under normal physiological conditions. Our model reduces computational time and provides a new approach for studying arterial pulse wave mechanics; e.g.,  the analyticity of our model allows for a direct identification of the role played by physical properties of the cardiovascular system on the pressure waves.

  4. The arterial blood supply for the synovial tendon sheaths of the hand.

    Science.gov (United States)

    de la Garza, Oscar; Lierse, Werner; de los Angeles-García, Ma; Elizondo, Rodrigo; Guzmán, Santos

    2008-01-01

    The blood supply for the synovial tendon sheaths of the hand was carefully investigated. We show that the origin of those arteries, supplying the synovial tendon-sheaths of the Mm. flexor pollicis longus, flexor digitorum superficialis and profundus, lies in the Canalis carpi. We also describe that the branches of the Aa. digitales palmares propriae arise independently. We emphasize that the terminal branches of the A. interossea posterior and the Rete carpi dorsalis form an arterial network on the synovial tendon sheaths of the Dorsum manus. The synovial membranes of the proximal joints of the fingers receive an ample blood supply from the Rami ascendentes of the Aa. metacarpeae palmares and the Aa. digitales palmares propriae (Aa. recurrentes).

  5. Predicting electrocardiogram and arterial blood pressure waveforms with different Echo State Network architectures.

    Science.gov (United States)

    Fong, Allan; Mittu, Ranjeev; Ratwani, Raj; Reggia, James

    2014-01-01

    Alarm fatigue caused by false alarms and alerts is an extremely important issue for the medical staff in Intensive Care Units. The ability to predict electrocardiogram and arterial blood pressure waveforms can potentially help the staff and hospital systems better classify a patient's waveforms and subsequent alarms. This paper explores the use of Echo State Networks, a specific type of neural network for mining, understanding, and predicting electrocardiogram and arterial blood pressure waveforms. Several network architectures are designed and evaluated. The results show the utility of these echo state networks, particularly ones with larger integrated reservoirs, for predicting electrocardiogram waveforms and the adaptability of such models across individuals. The work presented here offers a unique approach for understanding and predicting a patient's waveforms in order to potentially improve alarm generation. We conclude with a brief discussion of future extensions of this research.

  6. Arterial blood-pressure change and endogenous circulating substance P in man

    DEFF Research Database (Denmark)

    Henriksen, Jens Henrik Sahl; Kastrup, J; Schaffalitzky De Muckadell, O B

    1985-01-01

    Substance P (SP) is a powerful vasodilator and this peptide is today considered to be a chemical messenger. The potential effects on circulating SP of acute changes in arterial blood-pressure was investigated in nine subjects. An increase in arterial mean blood-pressure (+33%, P less than 0.001, n...... = 9) was obtained by infusion of angiotensin II and a decrease in pressure (-10%, P less than 0.005, n = 6) was obtained by ganglionic blockade. The concentration of SP in plasma, from supine subjects in the normotensive condition, ranged from 3 to 13 pmol/l (with a mean of 5.6 pmol/l). SP was thus...

  7. New Cardiovascular Indices Based on a Nonlinear Spectral Analysis of Arterial Blood Pressure Waveforms

    CERN Document Server

    Laleg, Taous-Meriem; Papelier, Yves; Crépeau, Emmanuelle; Sorine, Michel

    2007-01-01

    A new method for analyzing arterial blood pressure is presented in this report. The technique is based on the scattering transform and consists in solving the spectral problem associated to a one-dimensional Schr\\"odinger operator with a potential depending linearly upon the pressure. This potential is then expressed with the discrete spectrum which includes negative eigenvalues and corresponds to the interacting components of an N-soliton. The approach is similar to a nonlinear Fourier transform where the solitons play the role of sine and cosine components. The method provides new cardiovascular indices that seem to contain relevant physiological information. We first show how to use this approach to decompose the arterial blood pressure pulse into elementary waves and to reconstruct it or to separate its systolic and diastolic phases. Then we analyse the parameters computed from this technique in two physiological conditions, the head-up 60 degrees tilt test and the isometric handgrip test, widely used for...

  8. The Relationship between Portal Venous and Hepatic Arterial Blood Flow. I. Experimental Liver Transplantation

    Directory of Open Access Journals (Sweden)

    F. Jakab

    1996-01-01

    Full Text Available The relationship between the changes in portal venous and hepatic arterial blood flows, in the liver is a much disputed question, it has tremendous significance in the practice of transplantation, and an explanation has been available since 1981, when Lautt published the so-caled “adenosine washout theory”. According to our earlier observations the decrease of portal pressure or flow consistently led to an increase in hepatic artery flow. At the same time changes in hepatic artery flow or pressure seemed to produce only inconsistent effects on the portal circulation. In the present experiments liver transplantation (OLTX was carried out on mongrel dogs by Starzl's method. Electromagnetic flow probes were placed on the hepatic artery and the portal vein before removal of recipient’s liver, and after completion of all vascular anastomoses to the newly inserted liver, during the recirculatory phase of OLTX. The flow probes were connected to a Hellige electromagnetic flowmeter, portal venous and systemic arterial pressures were also recorded.

  9. No benefit of intraoperative whole blood sequestration and autotransfusion during coronary artery bypass grafting : results of a randomized clinical trial

    NARCIS (Netherlands)

    Ramnath, A N; Naber, H R; de Boer, A; Leusink, J A

    2003-01-01

    OBJECTIVES: In a randomized clinical trial of patients undergoing elective coronary artery bypass grafting, we evaluated the effect of intraoperative whole blood sequestration and autotransfusion on postoperative blood loss and the use of allogeneic blood products. METHODS: Male patients were includ

  10. [Large artery wall properties in dialyse and renal transplant patients with normal blood pressure].

    Science.gov (United States)

    Posadzy-Małaczyńska, Anna; Kosch, Marcus; Hausberg, Martin; Rahn, Karl H; Małaczyński, Paweł; Głuszek, Jerzy; Tykarski, Andrzej

    2004-01-01

    Structural and mechanical properties of the arterial wall are altered in patients with renal failure. Age and hypertension are known to affect the vessel wall structure. Aging process of arterial wall appears to be accelerated in patients with end-stage renal failure. The mechanisms responsible for reduced arterial compliance and distensibility in dialyse patients and renal transplant recipients without hypertension remain to be evaluated. 20 normotensive dialyse patients (D), 20 normotensive renal transplant recipients (T) and 20 healthy volunteers (N) matched for age, sex and blood pressure as controls were enrolled in to the study. Patients with cardiovascular risk factors and diabetes were excluded. The arterial blood pressure of all patients placed below 140/90 mmHg. The dialyse patients and renal transplant recipients were eligible for the study if the serum creatinine level was below 2 mg/dl. In all subjects, fasting concentrations of serum creatinine, total cholesterol, HDL-cholesterol, LDL-cholesterol, hemoglobin and glucose were determined at enrollment to the study. Long-term immunosuppression consisted of cyclosporine and prednisolone. Blood pressure was measured using an automatic sphygmomanometer (Criticon Dinamap model 1846 SX). Pulse wave velocity (PWV) was evaluated using non-invasive automatic Complior device. The vessel wall properties of the left common carotid artery were studied using multigate pulsed Doppler's system (Pie Medical Equipment BV Maastricht, The Netherlands). The frequency of transducer used was 7.5 MHz. With this non-invasive method, the end-diastolic diameter (d) and the systolic increase of vessel diameter (distension delta d) were measured using ECG trigger. From these data relative systolic increase of vessel diameter (delta d/d) and arterial wall distensibility coefficient (DC) were calculated. Simultaneously with the ultrasound measurements at the left common carotid artery carotid pulse waveforms are recorded using

  11. Value of arterial blood gas analysis in patients with acute dyspnea: an observational study

    OpenAIRE

    2011-01-01

    Introduction The diagnostic and prognostic value of arterial blood gas analysis (ABGA) parameters in unselected patients presenting with acute dyspnea to the Emergency Department (ED) is largely unknown. Methods We performed a post-hoc analysis of two different prospective studies to investigate the diagnostic and prognostic value of ABGA parameters in patients presenting to the ED with acute dyspnea. Results We enrolled 530 patients (median age 74 years). ABGA parameters were neither useful ...

  12. Possible key residues that determine left gastric artery blood flow response to PACAP in dogs

    Institute of Scientific and Technical Information of China (English)

    Satoru; Naruse; Kiyoshi; Nokihara; Victor; Wray; Tsuyoshi; Ozaki

    2010-01-01

    AIM:To determine the effect of pituitary adenylate cy-clase-activating polypeptide (PACAP) on left gastric artery (LGA) flow and to unveil the structural or functional important sites that may be critical for discrimination of different receptor subtypes. METHODS: Peptides, including PACAP-27, PACAP-38, amino acid substituted PACAP-27 and C-terminus truncated analogues PACAP (27-38), were synthesized by a simultaneous multiple solid-phase peptide synthesizer. Flow probes of an ultrasound transit-time blood ...

  13. Graphical arterial blood gas visualization tool supports rapid and accurate data interpretation.

    Science.gov (United States)

    Doig, Alexa K; Albert, Robert W; Syroid, Noah D; Moon, Shaun; Agutter, Jim A

    2011-04-01

    A visualization tool that integrates numeric information from an arterial blood gas report with novel graphics was designed for the purpose of promoting rapid and accurate interpretation of acid-base data. A study compared data interpretation performance when arterial blood gas results were presented in a traditional numerical list versus the graphical visualization tool. Critical-care nurses (n = 15) and nursing students (n = 15) were significantly more accurate identifying acid-base states and assessing trends in acid-base data when using the graphical visualization tool. Critical-care nurses and nursing students using traditional numerical data had an average accuracy of 69% and 74%, respectively. Using the visualization tool, average accuracy improved to 83% for critical-care nurses and 93% for nursing students. Analysis of response times demonstrated that the visualization tool might help nurses overcome the "speed/accuracy trade-off" during high-stress situations when rapid decisions must be rendered. Perceived mental workload was significantly reduced for nursing students when they used the graphical visualization tool. In this study, the effects of implementing the graphical visualization were greater for nursing students than for critical-care nurses, which may indicate that the experienced nurses needed more training and use of the new technology prior to testing to show similar gains. Results of the objective and subjective evaluations support the integration of this graphical visualization tool into clinical environments that require accurate and timely interpretation of arterial blood gas data.

  14. Two-Fluid Mathematical Models for Blood Flow in Stenosed Arteries: A Comparative Study

    Directory of Open Access Journals (Sweden)

    Sankar DS

    2009-01-01

    Full Text Available The pulsatile flow of blood through stenosed arteries is analyzed by assuming the blood as a two-fluid model with the suspension of all the erythrocytes in the core region as a non-Newtonian fluid and the plasma in the peripheral layer as a Newtonian fluid. The non-Newtonian fluid in the core region of the artery is assumed as a (i Herschel-Bulkley fluid and (ii Casson fluid. Perturbation method is used to solve the resulting system of non-linear partial differential equations. Expressions for various flow quantities are obtained for the two-fluid Casson model. Expressions of the flow quantities obtained by Sankar and Lee (2006 for the two-fluid Herschel-Bulkley model are used to get the data for comparison. It is found that the plug flow velocity and velocity distribution of the two-fluid Casson model are considerably higher than those of the two-fluid Herschel-Bulkley model. It is also observed that the pressure drop, plug core radius, wall shear stress and the resistance to flow are significantly very low for the two-fluid Casson model than those of the two-fluid Herschel-Bulkley model. Hence, the two-fluid Casson model would be more useful than the two-fluid Herschel-Bulkley model to analyze the blood flow through stenosed arteries.

  15. [Left ventricular relaxation and ambulatory blood pressure in mild, untreated arterial hypertension].

    Science.gov (United States)

    Herpin, D; Raynier, P; Ciber, M; Amiel, A; Boutaud, P; Demange, J

    1989-03-01

    Twenty patients with mild, untreated arterial hypertension had ambulatory blood pressure recordings and a digitized echocardiographic study of the left ventricle with measurement of its mass (LVM) and of relaxation parameters. A significant correlation was found between LVM and ambulatory systolic pressure during daytime (r = 0.64; p less than 0.01; n = 20) and during 24 hours (r = 0.79; p less than 0.001; n = 16). One of the relaxation parameters studied, the time taken to reach maximal speed of left ventricular enlargement, was closely related to the diurnal diastolic blood pressure (r = 0.58; p less than 0.01; n = 20), whereas in this population with mild arterial blood pressure none of the parameters was related to the amount of increase of LVM. One may therefore consider the abnormalities of left ventricular relaxation as likely to appear at an early stage of arterial hypertension; their discovery may antedate that of LVM and confirm that the hypertensive disease is real. However, the methodological problems encountered with type of exploration ought to be stressed: left ventricular relaxation is a multifactorial phenomenon, and its echocardiographic approach is subject to many hazards.

  16. A Mathematical Study on Three Layered Oscillatory Blood Flow Through Stenosed Arteries

    Institute of Scientific and Technical Information of China (English)

    Dharmendra Tripathi

    2012-01-01

    A mathematical model is constructed to examine the characteristics of three layered blood flow through the oscillatory cylindrical tube (stenosed arteries).The proposed model basically consists three layers of blood (viscous fluids with different viscosities) named as core layer (red blood cells),intermediate layer (platelets/white blood cells) and peripheral layer (plasma).The analysis was restricted to propagation of small-amplitude harmonic waves,generated due to blood flow whose wave length is larger compared to the radius of the arterial segment.The impacts of viscosity of fluid in peripheral layer and intermediate layer on the interfaces,average flow rate,mechanical efficiency,trapping and reflux are discussed with the help of numerical and computational results.This model is the generalized form of the preceding models.On the basis of present discussion,it is found that the size of intermediate and peripheral layers reduces in expanded region and enhances in contracted region with the increasing viscosity of fluid in peripheral layer,whereas,opposite effect is observed for viscosity of fluid in intermediate layer.Final conclusion is that the average flow rate and mechanical efficiency increase with the increasing viscosity of fluid in both layers,however,the effects of the viscosity of fluid in both layers on trapping and reflux are opposite to each other.

  17. Determining the Arterial Blood Pressure of People Living in Yesilyurt Local Healthcare Office

    Directory of Open Access Journals (Sweden)

    Feyza Dereli

    2009-02-01

    Full Text Available AIM: Whereas the prevalance of arterial blood pressure which was a chronical health problem was 20%-25% among 30 year-old people, them showing an increase in aging, the percentage went as high as 50% in 60’s and later ages. What was that worrisome was that despite the high prevalance, only half of these received treathment. This is study was descriptively and cross-sectionally planned to determine whether the people asking their tensions to be measured in and around the Yesilyurt local healthcare office region. METHODS: The environment of the research consisted of 1400 people over 35 age and registered Yesilyurt Local healthcare Office and the whole of the environment were included in this sample. The study was conducted over 340 voluntaries. The data was collected by a questionnaire of 14 questions containing socio-demografic features and by measuring the arterial blood pressure, height and weight of the individuals. In the evaluation of the data, chi-square test was used and the level of significantly was accepted as 0.05. RESULTS: In this study, the rate of high sistolic blood pressure was found to be 21.47% and the rate of high diastolic blood pressure to be 8.23%. It was determined that age and body mass index varrieties were effective on sistolic hipertension. It was also found that in their behaviors of the use of hypertensive medicine, of regular arterial pressure controls and of having the hypertesion diagnosis significant differnces varied statistically on both sistolic and diastolic blood pressure people having. CONCLUSION: In order to improve the health, informative information abouth hypertension was provided for the participants for too days consisting of 4 sessions. [TAF Prev Med Bull 2009; 8(1.000: 53-58

  18. [New artificial blood: sensation without any sensation (comments to the article in the journal New Scientist of 13 March, 2004)].

    Science.gov (United States)

    Ivanitskiĭ, G R; Maevskiĭ, E I

    2004-01-01

    In the article of Sylvia P. Westphal "New artificial blood shows promise" the sensational, at first sight, contention is adduced that numerous researchers engaged in the development of artificial blood substituents have many years followed the false pathway and did not understand the mechanisms of action of gas-transporting blood substituents, and now this understanding is available. In the paper being commented, the author gives three criteria that gas-transporting blood substituents must meet. The statement that the developers of gas-transporting blood substituents were unaware of these criteria is, in our opinion, questionable. We have known and have taken them into account development of the Russian gas-transporting blood substituent perftoran.

  19. Plasma volume expansion by albumin in cirrhosis. Relation to blood volume distribution, arterial compliance and severity of disease

    DEFF Research Database (Denmark)

    Brinch, Kim; Bendtsen, Flemming; Becker, Povl Ulrik;

    2003-01-01

    BACKGROUND/AIMS: The aim of the study was to investigate the effect of a standard albumin load on blood volume distribution, arterial compliance, and the renin-angiotensin-aldosterone system in patients with different degrees of cirrhosis. METHODS: 31 patients with cirrhosis (Child classes A/B/C=...... effective arterial blood volume of such patients, which may be important in the prevention of circulatory dysfunction....

  20. Antibacterial nitric oxide-releasing polyester for the coating of blood-contacting artificial materials.

    Science.gov (United States)

    Seabra, Amedea B; Martins, Dorival; Simões, Maíra M S G; da Silva, Regiane; Brocchi, Marcelo; de Oliveira, Marcelo G

    2010-07-01

    The emergence of multidrug-resistant bacteria associated with blood-contacting artificial materials is a growing health problem, which demands new approaches in the field of biomaterials research. In this study, a poly(sulfhydrylated polyester) (PSPE) was synthesized by the polyesterification reaction of mercaptosuccinic acid with 3-mercapto-1,2-propanediol and blended with poly(methyl methacrylate) (PMMA) from solution, leading to solid PSPE/PMMA films, with three different PSPE : PMMMA mass ratios. These films were subsequently S-nitrosated through the immersion in acidified nitrite solution, yielding poly(nitrosated)polyester/PMMA (PNPE/PMMA) films. A polyurethane intravascular catheter coated with PNPE/PMMA was shown to release nitric oxide (NO) in phosphate buffered saline solution (pH 7.4) at 37 degrees C at rates of 4.6 nmol/cm(2)/h in the first 6 h and 0.8 nmol/cm(2)/h in the next 12 h. When used to coat the bottom of culture plates, NO released from these films exerted a potent dose- and time-dependent antimicrobial activity against Staphylococcus aureus and a multidrug-resistant Pseudomonas aeruginosa strains. This antibacterial effect of PSPE/PMMA films opens a new perspective for the coating of blood-contacting artificial materials, for avoiding their colonization with highly resistant bacteria.

  1. Uterine artery blood flow in the periimplantation period in embryo transfer cycles

    Institute of Scientific and Technical Information of China (English)

    Ursula Zollner; Marie-Theres Specketer; Klaus-Peter Zollner; Johannse Dietl

    2012-01-01

    Objective:To assess the role of the uterine artery blood flow in the prediction of implantation in women undergoing embryo transfer during the periimplantation period.Methods:A total of 233 couples were included in this prospective study.All patients had embryo transfer,125 were performed inin-vitro fertilization/intracytoplasmic sperm injection(IVF/ICSI) and108 in cryo cycles.Ultrasound measurements were performed immediately before transfer.The pulsatility index(PI),Resistance index(RI) and the peak systolic velocity(PSV) were measured in both uterine arteries using endovaginal ultrasound.Results:InIVF/ICSI cycles the doppler parameters PI(2.48vs.2.15),RI(0.78vs.1.30) andPSV(60 vs.63) did not differ significantly between the pregnant and non-pregnant group.The pregnancy rate per transfer was similar in women showing an unilateral(24%), bilateral(33%) or no(27%) notch in the uterine blood flow.In cryo cycles the uterine artery blood flow parametersPI(3.2vs.3.0),RI(0.9vs.0.9) andPSV(53.2vs.51.2) did not differ either between pregnant and not pregnant patients.Conclusions:Previous studies were aiming at the measurement of arterial doppler parameters during the follicular phase which may not be adequate for the prediction of implantation.However, our results show that doppler studies during the early luteal phase of assisted reproductive technology cycles are not indicative for the likelihood of pregnancy, too.

  2. Fourier Analysis of Peripheral Blood Pressure and Flow in Intraoperative Assessment of Infrainguinal Arterial Reconstructions

    Directory of Open Access Journals (Sweden)

    Cheshmedzhiev Mihail V.

    2014-08-01

    Full Text Available AIM: To assess infrainguinal arterial reconstructions by intraoperative flowmetry under the distal anastomosis using a fast Fourier transformation; calculate and compare the amplitude ratios of peripheral arterial blood pressure and volume flow before and after drug-induced vasodilation of occluded bypass grafts and bypass grafts that have been patent at least for 1 year. To find what magnitude of the change of these ratios indicate a long-term patency of the bypass grafting. PATIENTS AND METHODS: We compared the results of the intraoperative flowmetry tests of 97 patients with infrainguinal arterial reconstructions. The patients were divided into two groups based on the graft status: the grafts in 49 patients were patent for at least a year, and 48 patients had failed bypass. We used a fast Fourier transform (FFT of the pressure and blood flow waves and compared the ratios of their amplitudes before and after administration of a vasodilator drug into the graft. Comparing the ratios obtained before and those after administration of the drug we quantified their change in each group and analysed them. RESULTS: After a drug-induced vasodilation, the blood pressure and flow amplitude ratios for the group with compromised reconstructions were less than 1.9 times smaller than those before drug infusion, while for the group with bypass grafts that had been functional for at least 12 months the ratios declined by more than 1.9≈2 times. CONCLUSION: The magnitude of the change of amplitude ratios of the peripheral pressure and volume flow after drug-induced vasodilation can be used to make an assessment of the bypass graft and the distal arterial segment.

  3. Radiopharmaceutical uptake as a marker of sternal blood supply following internal mammary artery harvesting.

    Science.gov (United States)

    Rivas, L F; Hawkins, T; Morritt, G N; Behl, R P; Griffin, S C; Brown, A H

    1994-04-01

    To evaluate the impact of internal mammary artery harvesting on sternal blood supply after open heart surgery, a conventional bone scan was performed 7 days after operation in 30 patients. After administration of 370 MBq of technetium 99 m-medronic acid complex, imaging was carried out at the level of the sternum and including the humerus as a reference. A quantitative analysis of uptake (sternum/humerus uptake index) was performed and compared in three different groups of patients: group A, ten patients who had only vein grafts or valve surgery; group B, ten patients with single internal mammary artery harvesting; and group C, ten patients with bilateral internal mammary artery harvesting. These results were compared with 24 non-surgical subjects as a control (group D). Although intervention had a significant influence in raising the uptake index of the surgical groups (A = 3.34; B = 3.09 and C = 3.48) when compared with normal subjects (D = 2.45) (P 0.05). It was concluded that the vascular supply of the sternum is not entirely dependent upon the internal mammary arteries and that mobilization of both vessels does not cause per se additional serious impact to the bone vascularization after midline sternotomy, at least beyond day 7 after operation.

  4. Effect of TIPS placement on portal and splanchnic arterial blood flow in 4-dimensional flow MRI

    Energy Technology Data Exchange (ETDEWEB)

    Stankovic, Zoran [Northwestern University, Department of Radiology, Feinberg School of Medicine, Chicago, IL (United States); University Medical Center Freiburg, Department of Diagnostic Radiology and Medical Physics, Freiburg (Germany); Roessle, Martin; Schultheiss, Michael [University Medical Center Freiburg, Department of Gastroenterology, Freiburg (Germany); Euringer, Wulf; Langer, Mathias [University Medical Center Freiburg, Department of Diagnostic Radiology and Medical Physics, Freiburg (Germany); Salem, Riad; Barker, Alex; Carr, James; Collins, Jeremy D. [Northwestern University, Department of Radiology, Feinberg School of Medicine, Chicago, IL (United States); Markl, Michael [Northwestern University, Department of Radiology, Feinberg School of Medicine, Chicago, IL (United States); Northwestern University, Department of Biomedical Engineering, McCormick School of Engineering, Chicago, IL (United States)

    2015-09-15

    To assess changes in portal and splanchnic arterial haemodynamics in patients undergoing transjugular intrahepatic portosystemic shunt (TIPS) using four-dimensional (4D) flow MRI, a non-invasive, non-contrast imaging technique. Eleven patients undergoing TIPS implantation were enrolled. K-t GRAPPA accelerated non-contrast 4D flow MRI of the liver vasculature was applied with acceleration factor R = 5 at 3Tesla. Flow analysis included three-dimensional (3D) blood flow visualization using time-resolved 3D particle traces and semi-quantitative flow pattern grading. Quantitative evaluation entailed peak velocities and net flows throughout the arterial and portal venous (PV) systems. MRI measurements were taken within 24 h before and 4 weeks after TIPS placement. Three-dimensional flow visualization with 4D flow MRI revealed good image quality with minor limitations in PV flow. Quantitative analysis revealed a significant increase in PV flow (562 ± 373 ml/min before vs. 1831 ± 965 ml/min after TIPS), in the hepatic artery (176 ± 132 ml/min vs. 354 ± 140 ml/min) and combined flow in splenic and superior mesenteric arteries (770 ml/min vs. 1064 ml/min). Shunt-flow assessment demonstrated stenoses in two patients confirmed and treated at TIPS revision. Four-dimensional flow MRI might have the potential to give new information about the effect of TIPS placement on hepatic perfusion. It may explain some unexpected findings in clinical observation studies. (orig.)

  5. Splenic artery embolization with Ankaferd blood stopper in a sheep model

    Science.gov (United States)

    Koç, Osman; Acar, Kadir; Özbek, Orhan; Güler, İbrahim; Sarıtaş, Kadir; Erdem, Tuba Bera; Solak, Yalçın; Toy, Hatice; Küçükapan, Ahmet; Özbek, Seda; Gaipov, Abduzhappar; Haznedaroğlu, İbrahim C.

    2016-01-01

    PURPOSE Splenic artery embolization is a minimally invasive therapeutic procedure utilized in a number of disorders. Ankaferd blood stopper (ABS) is a novel hemostatic agent with a new mechanism of action independent of clotting factors. We aimed to investigate the safety and efficiency of ABS for splenic artery embolization in a sheep model. METHODS Seven adult female sheep were included in the study. Selective celiac angiography was performed using a 5F diagnostic catheter and then a 2.7F hydrophilic coating microcatheter was advanced coaxially to the distal part of the main splenic artery. Under fluoroscopic guidance, 6 mL mixture composed of half-and-half ABS and contrast agent was slowly injected. Fluoroscopy was used to observe the deceleration and stagnation of the flow. Control celiac angiograms were obtained immediately after the embolization. After the procedure, the animals were observed for one day and then sacrificed with intravenous sodium thiopental. RESULTS Technical success rate was 100%. None of the animals died or experienced a major systemic adverse event during the procedure. All of the spleens appeared dark on macroscopic examination due to excessive thrombosis. Microscopically, the majority of the splenic sinusoids (90%–95%) were necrotic. CONCLUSION In our study, splenic artery embolization by ABS was found to be safe and effective in the shortterm. Further studies are needed to better understand the embolizing potential of this novel hemostatic agent. PMID:27306661

  6. Wall morphology, blood flow and wall shear stress: MR findings in patients with peripheral artery disease

    Energy Technology Data Exchange (ETDEWEB)

    Galizia, Mauricio S.; Barker, Alex; Collins, Jeremy; Carr, James [Northwestern University, Department of Radiology, Feinberg School of Medicine, Chicago, IL (United States); Liao, Yihua [Northwestern University' s Feinberg School of Medicine, Department of Preventive Medicine, Chicago, IL (United States); McDermott, Mary M. [Northwestern University' s Feinberg School of Medicine, Department of Preventive Medicine, Chicago, IL (United States); Northwestern University' s Feinberg School of Medicine, Department of Medicine, Chicago, IL (United States); Markl, Michael [Northwestern University, Department of Radiology, Feinberg School of Medicine, Chicago, IL (United States); Northwestern University, Department Biomedical Engineering, McCormick School of Engineering, Chicago, IL (United States)

    2014-04-15

    To investigate the influence of atherosclerotic plaques on femoral haemodynamics assessed by two-dimensional (2D) phase-contrast (PC) magnetic resonance imaging (MRI) with three-directional velocity encoding. During 1 year, patients with peripheral artery disease and an ankle brachial index <1.00 were enrolled. After institutional review board approval and written informed consent, 44 patients (age, 70 ± 12 years) underwent common femoral artery MRI. Patients with contra-indications for MRI were excluded. Sequences included 2D time-of-flight, proton-density, T1-weighted and T2-weighted MRI. Electrocardiogram (ECG)-gated 2D PC-MRI with 3D velocity encoding was acquired. A radiologist classified images in five categories. Blood flow, velocity and wall shear stress (WSS) along the vessel circumference were quantified from the PC-MRI data. The acquired images were of good quality for interpretation. There were no image quality problems related to poor ECG-gating or slice positioning. Velocities, oscillatory shear stress and total flow were similar between patients with normal arteries and wall thickening/plaque. Patients with plaques demonstrated regionally increased peak systolic WSS and enhanced WSS eccentricity. Combined multi-contrast morphological imaging of the peripheral arterial wall with PC-MRI with three-directional velocity encoding is a feasible technique. Further study is needed to determine whether flow is an appropriate marker for altered endothelial cell function, vascular remodelling and plaque progression. (orig.)

  7. Vasopressin contributes to maintenance of arterial blood pressure in dehydrated baboons.

    Science.gov (United States)

    Ryan, K L; Thornton, R M; Proppe, D W

    1989-02-01

    This study primarily sought to determine whether the role of vasopressin (VP) in maintenance of arterial blood pressure is enhanced in awake, chronically instrumented baboons after 68-72 h of dehydration. This question was approached by pharmacologically blocking vasopressin V1-receptors in euhydrated and dehydrated baboons with or without a normally functioning renin-angiotensin system (RAS). VP blockade during dehydration produced a rapidly occurring (within 5 min), statistically significant (P less than 0.05) decrease in mean arterial pressure (MAP) of 5 +/- 1 mmHg in the RAS-intact condition and an identical decline in MAP (5 +/- 1 mmHg) during blockade of the RAS by captopril, an angiotensin I-converting enzyme inhibitor. At 15 min after induction of VP blockade, heart rate was elevated by 9 +/- 2 beats/min in the RAS-intact condition and by 20 +/- 5 beats/min in the RAS-blocked condition. In addition, VP blockade in the dehydrated state produced small and equal increases in hindlimb vascular conductance in RAS-intact and RAS-blocked conditions. None of these cardiovascular changes were produced by VP blockade in the euhydrated state. RAS blockade produced modest declines in MAP in both hydration states, but the fall was larger by 7 +/- 4 mmHg in the dehydrated state. Thus both VP and the RAS contribute to the maintenance of arterial blood pressure during dehydration in the conscious baboon.

  8. Correlation study of uterine spiral artery blood flow characteristics with placental development and hypoxia in patients with preeclampsia

    Institute of Scientific and Technical Information of China (English)

    Rong Ma

    2016-01-01

    Objective:To study the correlation of uterine spiral artery blood flow characteristics with placental development and hypoxia in patients with preeclampsia.Methods:A total of 66 patients diagnosed with preeclampsia in our hospital between June 2013 and May 2016 were selected as the preeclampsia group (PE group) of the study and healthy women who gave birth in our hospital during the same period were selected as control group. At 32-37 weeks of gestation, uterine spiral artery ultrasonography was conducted to determine blood flow parameters PI, RI and S/D, and peripheral blood was collected to separate mononuclear cells and then determine CTLA-4 and CD28 mRNA level; after childbirth, placenta tissue was collect to determine the levels of placental development-related cytokines and apoptotic molecules.Results: Uterine spiral artery RI, PI and S/D of PE group were significantly higher than those of control group; PLGF, NGF, EGF, IGF-I, VEGF, Xiap, Survivin, bcl-2 and CD28 content in placenta tissue of PE group were significantly lower than those of control group and negatively correlated with uterine spiral artery PI, RI and S/D while GDF-15, caspase-3, caspase-9 and CTLA-4 content were significantly higher than those of control group and positively correlated with uterine spiral artery PI, RI and S/D; CTLA-4 mRNA level in peripheral blood mononuclear cells of PE group was significantly higher than that of control group and positively correlated with uterine spiral artery were PI, RI and S/D while CD28 mRNA level was significantly lower than that of control group and negatively correlated with uterine spiral artery PI, RI and S/D.Conclusion:Uterine spiral artery blood flow resistance increases and blood flow volume decreases in patients with preeclampsia, and the above blood flow characteristics will hinder the placental development, induce cell apoptosis and aggravate the placental hypoxia.

  9. Predictive value of red blood cell distribution width for coronary artery lesions in patients with Kawasaki disease.

    Science.gov (United States)

    Xu, Haiyan; Fu, Songling; Wang, Wei; Zhang, Qing; Hu, Jian; Gao, Lichao; Zhu, Weihua; Gong, Fangqi

    2016-08-01

    Recent studies have shown that elevated red blood cell distribution width is associated with poor outcome in cardiovascular diseases. In order to assess the predictive value of red blood cell distribution width, before treatment with intravenous immunoglobulins, for coronary artery lesions in patient with Kawasaki disease, we compared 83 patients with coronary artery lesions and 339 patients without coronary artery lesions before treatment with intravenous immunoglobulin. Clinical, echocardiographic, and biochemical values were evaluated along with red blood cell distribution width. A total of 422 consecutive patients with Kawasaki disease were enrolled into our study. According to receiver operating characteristic curve analysis, the optimal red blood cell distribution width cut-off value for predicting coronary artery lesions was 14.55% (area under the curve was 0.721; p=0.000); eighty-three patients (19.7%) had coronary artery lesions, and 70% of the patients with coronary artery lesions had red blood cell distribution width level >14.55%. Logistic regression analysis revealed that fever duration >14 days (odds ratio was 3.42, 95% confidence interval was 1.27-9.22; p=0.015), intravenous immunoglobulin resistance (odds ratio was 2.33, 95% confidence interval was 1.02-5.29; p=0.04), and red blood cell distribution width >14.55% (odds ratio was 3.49, 95% confidence interval was 2.01-6.05; p=0.000) were independent predictors of coronary artery lesions in patients with Kawasaki disease. In Conclusion, red blood cell distribution width may be helpful for predicting coronary artery lesions in patients with Kawasaki disease.

  10. Renal blood flow regulation and arterial pressure fluctuations: a case study in nonlinear dynamics

    DEFF Research Database (Denmark)

    Holstein-Rathlou, N H; Marsh, D J

    1994-01-01

    The arterial blood pressure, a physiological variable on which all renal excretory processes depend, fluctuates over a wide range of amplitudes and frequencies. Much of this variation originates in nonrenal vascular beds to support nonrenal tasks, and the fluctuations provide a noisy environment...... a relatively noise-free environment in which to work. Because of the time-varying nature of the blood pressure, we have concentrated in this review on the now substantial body of work on the dynamics of renal blood flow regulation and the underlying mechanisms. Renal vascular control mechanisms are not simply...... of experimental hypertension provide tubular pressure records that pass statistical tests for ordered structure and sensitive dependence on initial conditions in the reconstructed state space, two of the hallmarks of deterministic chaos. These records also pass recent more stringent tests for chaos...

  11. Healing of ulcers on the feet correlated with distal blood pressure measurements in occlusive arterial disease

    DEFF Research Database (Denmark)

    Holstein, P; Lassen, N A

    1980-01-01

    The frequency of healing in subchronic ulcers in 66 feet in 62 patients with arterial occlusive disease was correlated with the systolic digital blood pressure (SDBP) and the systolic ankle blood pressure (SABP), both measured with a strain gauge, and with the skin perfusion pressure on the heel...... of healing correlated significantly with the three distal blood pressure parameters investigated, the closest correlation being with the SDBP measured at the final examination, i.e. just after healing of the ulcer or just before an inevitable major amputation. Of the 22 cases with SDBP below 20 mmHg only two...... (SPPH) as measured with a photocell. Thirty-two patients (35 feet with ulcerations) had diabetes mellitus. The treatment was conservative. In 42 feet the ulcers healed after an average period of 5.8 months; in 24 feet major amputation became necessary after an average of 4.3 months. The frequency...

  12. Physiological importance of the coronary arterial blood supply to the rattlesnake heart

    DEFF Research Database (Denmark)

    Hagensen, Mette; Abe, Augusto S.; Falk, Erling;

    2008-01-01

    supply to the outer compact layer in untreated snakes. Electrocardiogram (ECG), blood pressure (Psys) and heart rate (fH) were measured at rest and during enforced activity at day 1 and 4. Four days after occlusion of the coronary circulation, the snakes could still maintain a Psys and fH of 5.2±0.2 k......Pa and 58.2±2.2 beats min-1, respectively, during activity and the ECG was not affected. This was not different from sham-operated snakes. Thus, while the outer compact layer of the rattlesnake heart clearly has an extensive coronary supply, rattlesnakes sustain a high blood pressure and heart rate during...... remains unknown. In the present study we investigate the effects of permanent coronary artery occlusion in the South American rattlesnake (Crotalus durissus) on the ability to maintain heart rate and blood pressure at rest and during short term activity. We used colored silicone rubber (Microfil...

  13. Corrections of arterial input function for dynamic H215O PET to assess perfusion of pelvic tumours: arterial blood sampling versus image extraction

    Science.gov (United States)

    Lüdemann, L.; Sreenivasa, G.; Michel, R.; Rosner, C.; Plotkin, M.; Felix, R.; Wust, P.; Amthauer, H.

    2006-06-01

    Assessment of perfusion with 15O-labelled water (H215O) requires measurement of the arterial input function (AIF). The arterial time activity curve (TAC) measured using the peripheral sampling scheme requires corrections for delay and dispersion. In this study, parametrizations with and without arterial spillover correction for fitting of the tissue curve are evaluated. Additionally, a completely noninvasive method for generation of the AIF from a dynamic positron emission tomography (PET) acquisition is applied to assess perfusion of pelvic tumours. This method uses a volume of interest (VOI) to extract the TAC from the femoral artery. The VOI TAC is corrected for spillover using a separate tissue TAC and for recovery by determining the recovery coefficient on a coregistered CT data set. The techniques were applied in five patients with pelvic tumours who underwent a total of 11 examinations. Delay and dispersion correction of the blood TAC without arterial spillover correction yielded in seven examinations solutions inconsistent with physiology. Correction of arterial spillover increased the fitting accuracy and yielded consistent results in all patients. Generation of an AIF from PET image data was investigated as an alternative to arterial blood sampling and was shown to have an intrinsic potential to determine the AIF noninvasively and reproducibly. The AIF extracted from a VOI in a dynamic PET scan was similar in shape to the blood AIF but yielded significantly higher tissue perfusion values (mean of 104.0 ± 52.0%) and lower partition coefficients (-31.6 ± 24.2%). The perfusion values and partition coefficients determined with the VOI technique have to be corrected in order to compare the results with those of studies using a blood AIF.

  14. Increased wall tension in response to vasoconstrictors in isolated mesenteric arterial rings from patients with high blood pressure.

    Science.gov (United States)

    Tahvanainen, Anna; Taurio, Jyrki; Mäki-Jouppi, Jenni; Kööbi, Peeter; Mustonen, Jukka; Kähönen, Mika; Sand, Juhani; Nordback, Isto; Pörsti, Ilkka

    2006-12-01

    Essential hypertension is associated with several alterations in arterial function. A wealth of information from animal models is available concerning hypertensive changes in the mesenteric circulation, while only few studies have examined human mesenteric arterial function. The tone of isolated mesenteric arterial segments (outer diameter 0.7-0.9 mm) was examined from individuals with high (n=17) or normal (n=22) blood pressure, grouped using the current definition of elevated blood pressure (140/90 mmHg). Since the majority of them were operated because of malignancies, we evaluated whether functional vascular properties provided information about patient prognosis. Wall tension development (mN/mm) in response to vasoconstrictors (noradrenaline, 5-hydroxy tryptamine, potassium chloride) was higher in mesenteric arterial rings from patients with high than normal blood pressure. There was no difference in vasoconstrictor sensitivity, or endothelium-dependent and endothelium-independent vasorelaxation. Arterial segment weight was higher in hypertensive subjects, suggesting vascular wall hypertrophy. The 10-year follow-up showed no differences in the control of arterial tone between the surviving (n=14) or deceased (n=25) patients. In conclusion, isolated mesenteric arterial segments from hypertensive patients showed increased wall tension in response to vasoconstrictors. Since the mesenteric circulation is an important regulator of peripheral arterial resistance, possible functional alterations in this vascular bed should be further investigated in hypertensive patients.

  15. Impact of autologous blood transfusion on the use of pack of red blood cells in coronary artery bypass grafting surgery

    Directory of Open Access Journals (Sweden)

    Leonardo Leiria de Moura da Silva

    2013-06-01

    Full Text Available OBJECTIVE: To evaluate the impact of Cell Saver autologous blood transfusion system (CS on the use of packed red blood cells (pRBC in coronary artery bypass grafting (CABG surgery. METHODS: We carried out a retrospective cross-sectional study in 87 patients undergoing primary elective CABG with miniaturized cardiopulmonary bypass (miniCPB, divided in two groups: 44 without-CS and 43 with-CS. We investigated the necessity of absolute use and the volume of packed red blood cells (pRBC in each group, as well as cardiovascular risk factors, presurgical variables and intraoperative surgical parameters. All data were collected from medical records and there was no randomization or intervention on group selection. Statistical analysis was performed with Student t-test, Mann-Whitney U-test and χ² test, with a 5% significance level. RESULTS: There were no significant differences between the two groups in terms of cardiovascular risk factors and pre and intraoperative variables. Evaluating the absolute use of pRBC during surgery, there was a statistically significant difference (P=0.00008 between the groups without-CS (21/44 cases; 47.7% and with-CS (4/43 cases; 9.3%. There was also a statistically significant difference (P=0.000117 in the volumes of pRBC between the groups without-CS (198.651258.65ml and with-CS (35.061125.67ml. On the other hand, in the early postoperative period (up to 24h there was no difference regarding either the absolute use or the volumes of pRBC between both studied groups. CONCLUSION: Autologous erythrocyte transfusion with CS use reduces the use of intraoperative homologous pRBC in coronary artery bypass grafting surgeries associated with miniCPB.

  16. The Changes of Arterial Blood Gases in COPD During Four-year Period

    Science.gov (United States)

    Cukic, Vesna

    2014-01-01

    ABSTRACT Introduction: COPD (Chronic Obstructive Pulmonary Disease) is characterized by airflow limitation that is not fully reversible and that can lead to respiratory failure. Objective: to show the changes of arterial blood gases in COPD during the 4 -year evolution of illness. Material and Methods: The research was done on patients suffering from COPD treated at the Clinic “Podhrastovi” during 2006 and 2007 year. The tested parameters were examined from the date of receiving patient with COPD to hospital treatment in 2006 and 2007 and then followed prospectively until 2010 or 2011 year (the follow-up period was 4 years). There were total 199 treated patients who were chosen at random and regularly attended the control examinations. The study was conducted on adult patients of both sexes, different age group. In each patient the duration of illness was recorded so is sex, age, data of smoking habits, information about the regularity of taking bronchodilator therapy during remissions of disease, about the treatment of disease exacerbations, results of blood gases analysis as follows : pH value, PaO2 (partial pressure of oxygen in arterial blood), PaCO2 (partial pressure of carbon dioxide in arterial blood). All these parameters were measured at the beginning and at the end of each hospital treatment. We took in elaboration data obtained in the beginning of the first hospitalization and at the end of the last hospitalization or at the last control in outpatient department when patient was in stable state. Patients were divided into three groups according to the number of exacerbations per year. Results: there is the statistically significant decrease of PaO2 (p<0.01) and pH, (p<0.05) and an increase of PaCO2 (p<0.01) during follow-up period. But in patients regularly treated in phases of remission and exacerbations of illness the course of illness is slower. The decrease of pH and PaO2 and increase of PaCO2 is statistically significantly smaller in those

  17. The blood flow in the posterior communicant artery. Angiographic study by using magnetic resonance

    CERN Document Server

    Portela, L A P

    1995-01-01

    did not change the direction of flow present, in the circumstances of this study. The arterial circle of Willis is the most important collateral pathway for the cerebral vessels when one the afferents is occluded. Its normal function, without vascular compromise, has been considered in conflicting ways in the literature. For centuries after its description by Thomas Willis in 1664 it was considered a flow equalizer, with free admixture of blood within it. Since the beginning of this century the dominant view is one of a potential value only, with null effective flow in the communicating arteries. The premise is included in different experimental models. Alternatively, it was considered that the normal direction of flow is antero-posterior, from carotid to posterior cerebral, since carotid flow is greater. Using phase-contrast magnetic resonance angiography, a non-invasive qualitative method, it was found in 40 patients without morphological brain abnormality and in 10 healthy volunteers that flow can be seen ...

  18. Range-gated pulsed Doppler ultrasonographic evaluation of carotid arterial blood flow in small preterm infants with patent ductus arteriosus.

    Science.gov (United States)

    Wilcox, W D; Carrigan, T A; Dooley, K J; Giddens, D P; Dykes, F D; Lazzara, A; Ray, J L; Ahmann, P A

    1983-02-01

    Range-gated pulsed Doppler (RGPD) ultrasonography was utilized to study the effect of a patent ductus arteriosus (PDA) on carotid arterial blood flow in small preterm infants. Carotid arterial flow velocity studies were performed on 23 preterm infants, sampling right and left carotid arteries. Studies on seven infants after PDA ligation and on seven who developed no evidence of PDA were used as controls. A strong relationship was demonstrated between diastolic reversal in the carotid arteries and PDA. The results of this study indicate that the RGPD flow velocity curve from the carotid artery is more sensitive than M-mode echocardiography or clinical examination in detecting PDA, and that PDA in small preterm infants is associated with a distinct abnormality in the carotid arterial flow pattern.

  19. [The use of a synthetic vascular artificial prosthesis or arterial homograft in cases of patients with the arteriosclerosis and terminal insufficiency of kidney cured by the kidney transplantation].

    Science.gov (United States)

    Pupka, Artur; Blocher, Dariusz; Staniszewski, Tomasz; Płonek, Tomasz; Bogdan, Justyna

    2009-01-01

    Arterial transplantations were practiced in the vascular surgery since the beginning of her formation but without successes in the distant observation. Transplantation of a kidney is a routine conduct in the treatment of the decadent incapacity of a kidney. The dissertation concerns a use of arterial allografts kept using a method of a cold ischaemia in the protective liquid or synthetic vascular dacron artificial limbs or PTFE used as arterial foot-bridges at patients with the atherosclerotic obstruction aortal-pelvic, treated with the kidney transplantation. The arterial transplant is created from the aorta, arteria iliacas common and externa, femoral arteries common and superficial. A tissue material is kept using the method of the cold ischaemia and practical as the aortal foot-bridge-femoral or aortal-two-femoral at classified earlier patients being subjecteds to transfusion. The other way of a transplantation of a kidney at patients with the arteriosclerosis is the realization earlier or one-temporarily the vascular foot-bridge with use of the synthetic artificial limb. It seems that vascular artificial limbs about enlarged resistance on the contagion should be used in such a case. Sonographic examinations with duplex doppler and angiography are performed in all cases. The analysis of such cures can make a creation of the most profitable algorithm of the conduct possible in cases of patients suffering from ischaemia of lower limbs and requiring a transplantation of a kidney because of its incapacity.

  20. Arterial blood pressure is closely related to ascites development in compensated HCV-related cirrhosis.

    Directory of Open Access Journals (Sweden)

    Eduardo Vilar Gomez

    Full Text Available BACKGROUND: Arterial blood pressure (BP is a reliable marker of circulatory dysfunction in cirrhotic patients. There are no prospective studies evaluating the association between different levels of arterial BP and ascites development in compensated cirrhotic patients. Therefore, we evaluated the relationship between arterial BP and ascites development in compensated cirrhotic patients. MATERIALS AND METHODS: A total of 402 patients with compensated HCV-related cirrhosis were prospectively followed during 6 years to identify ascites development. At baseline, patients underwent systolic, diastolic and mean arterial pressure (MAP measurements. Any history of arterial hypertension was also recorded. The occurrence of events such as bleeding, hepatocellular carcinoma, death and liver transplantation prior to ascites development were considered as competing risk events. RESULTS: Over a median of 156 weeks, ascites occurred in 54 patients (13%. At baseline, MAP was significantly lower in patients with ascites development (75.9 mm/Hg [95%CI, 70.3-84.3] than those without ascites (93.6 mm/Hg [95% CI: 86.6-102.3]. After adjusting for covariates, the 6-year cumulative incidence of ascites was 40% (95%CI, 34%-48% for patients with MAP<83.32 mm/Hg. In contrast, cumulative incidences of ascites were almost similar among patients with MAP values between 83.32 mm/Hg and 93.32 mm/Hg (7% [95% CI: 4%-12%], between 93.32 mm/Hg and 100.31 mm/Hg (5% [95% CI: 4%-11%] or higher than 100.31 mm/Hg (3% [95% CI: 1%-6%]. The MAP was an independent predictor of ascites development. CONCLUSIONS: The MAP is closely related to the development of ascites in compensated HCV-related cirrhosis. The risk of ascites development increases in 4.4 fold for subjects with MAP values <83.32 mm/Hg.

  1. Mean arterial pressure change associated with cerebral blood flow in healthy older adults.

    Science.gov (United States)

    Deverdun, Jeremy; Akbaraly, Tasnime N; Charroud, Celine; Abdennour, Meriem; Brickman, Adam M; Chemouny, Stephane; Steffener, Jason; Portet, Florence; Bonafe, Alain; Stern, Yaakov; Ritchie, Karen; Molino, François; Le Bars, Emmanuelle; Menjot de Champfleur, Nicolas

    2016-10-01

    We investigate over a 12-year period the association between regional cerebral blood flow (CBF) and cardiovascular risk factors in a prospective cohort of healthy older adults (81.96 ± 3.82 year-old) from the Cognitive REServe and Clinical ENDOphenotype (CRESCENDO) study. Cardiovascular risk factors were measured over 12 years, and gray matter CBF was measured at the end of the study from high-resolution magnetic resonance imaging using arterial spin labeling. The association between cardiovascular risk factors, their long-term change, and CBF was assessed using multivariate linear regression models. Women were observed to have higher CBF than men (p < 0.05). Increased mean arterial pressure (MAP) over the 12-year period was correlated with a low cerebral blood flow (p < 0.05, R(2) = 0.21), whereas no association was detected between CBF and MAP at the time of imaging. High levels of glycemia tended to be associated with low cerebral blood flow values (p < 0.05). Age, alcohol consumption, smoking status, body mass index, history of cardiovascular disease, and hypertension were not associated with CBF. Our main result suggests that change in MAP is the most significant predictor of future CBF in older adults.

  2. Evaluation of MR angiography and blood flow measurement in abdominal and peripheral arterial occlusive disease

    Energy Technology Data Exchange (ETDEWEB)

    Tabuchi, Kenji [Dokkyo Univ. School of Medicine, Mibu, Tochigi (Japan)

    2000-03-01

    To assess the characteristics of blood flow measurement with MR Angiography (MRA) to evaluate the status of vascular stenoses, two or three dimensional time-of-flight MRA and velocity-encoded cine MR were performed in the 230 segments of 35 patients, with abdominal and peripheral arterial occlusive diseases. In 11 of these 35 patients digital subtraction angiography was additionally underwent, and the stenotic findings was compared with MRA. There were 17 segments in which the velocity could not be measured, because the blood flow exceeded the upper limit of peak-encoded velocity (VENC) which was set at 120 cm/sec. Therefore, it is necessary to set the upper limit of VENC at higher than 120 cm/sec. There were 11 stenotic findings in DSA and 20 stenotic findings in MRA. Pulsatility Index (PI=(max velocity-min. velocity)/average velocity) were used for evaluating the blood flow waveform, and there were significant difference between the 11 stenotic findings of DSA and the others'. In summery, MRA was considered as useful examination to assess the degree of the vascular stenoses in abdominal and peripheral arterial occlusive disease. (author)

  3. Pelvic magnetic resonance imaging angioanatomy of the arterial blood supply to the penis in suspected prostate cancer patients

    Energy Technology Data Exchange (ETDEWEB)

    Thai, Cao Tan, E-mail: bstanhatinh@gmail.com [Department of Urology, Brabois Hospital, University Hospital of Nancy, Rue du Morvan, 54500 Vandoeuvre Lès Nancy Cedex (France); IADI Laboratory, INSERM-U947, Brabois Hospital, University Hospital of Nancy, Tour Drouet, rue du Morvan, 54511 Vandoeuvre Lès Nancy Cedex (France); Karam, Ibrahim Michel [Clinical Epidemiology and Evaluation Department, University Hospital of Nancy (France); Department of Anatomy, Faculty of Medicine Nancy, 9 Avenue de la Foret de haye BP, 54505 Vandoeuvre Lès Nancy Cedex (France); Nguyen-Thi, Phi Linh [Clinical Epidemiology and Evaluation Department, University Hospital of Nancy (France); INSERM, CIC-EC CIE6, 92 Avenue du Maréchal de Lattre de Tassigny, 54000 Nancy (France); Lefèvre, Frédéric [Department of Radiology, Brabois Hospital, University Hospital of Nancy, Rue du Morvan, 54500 Vandoeuvre Lès Nancy Cedex (France); Hubert, Jacques [Department of Urology, Brabois Hospital, University Hospital of Nancy, Rue du Morvan, 54500 Vandoeuvre Lès Nancy Cedex (France); IADI Laboratory, INSERM-U947, Brabois Hospital, University Hospital of Nancy, Tour Drouet, rue du Morvan, 54511 Vandoeuvre Lès Nancy Cedex (France); Felblinger, Jacques [IADI Laboratory, INSERM-U947, Brabois Hospital, University Hospital of Nancy, Tour Drouet, rue du Morvan, 54511 Vandoeuvre Lès Nancy Cedex (France); Eschwège, Pascal [Department of Urology, Brabois Hospital, University Hospital of Nancy, Rue du Morvan, 54500 Vandoeuvre Lès Nancy Cedex (France)

    2015-05-15

    Highlights: • Three patterns of penile arterial supply (according to the classification of Stéphane Droupy). • Our classification about accessory pudendal artery. • Origin of accessory pudendal artery. - Abstract: Purpose: To describe the internal pudendal artery (IPA) and accessory pudendal artery (APA) detected by magnetic resonance (MR) angiography to help surgeons to find and preserve them during radical prostatectomy (RP). Materials and methods: Constrast-enhanced MR 3.0 T angiography of the pelvis were performed in 111 male patients suspected diagnosis of prostate cancer (PCa), and describe the penile arterial blood supply. Results: There are three patterns of the arterial blood supply to the penis (IPA and/or APA) accounting for 51.4%, 46.8% and 1.8% of cases, respectively. About the accessory pudendal artery (APA): 54/111 (48.6%) patients had APA with five different branching patterns, they were type I (APA bilateral symmetry): 17 (31.5%); type II (APA bilateral asymmetry): 1 (1.9%); type III (APA unilateral lateral): 13 (24%); type IV (APA unilateral apical): 21 (38.9%); type V (APA unilateral mix): 2 (3.7%). APA origin were from inferior epigastric artery (IEA): 7 (9.5%); from inferior vesical artery (IVA): 32 (43.2%); from obturator artery (OA): 35 (47.3%). Conclusion: A precise angioanatomic evalutation of arteries destined to the penis by MR angiography pre-operation for male pelvic organs will help surgeons to preserve them and contributes to reduce the erectile dysfunction after these procedures.

  4. Quantification of myocardial blood flow and blood flow reserve in the presence of arterial dispersion: a simulation study.

    Science.gov (United States)

    Schmitt, Melanie; Viallon, Magalie; Thelen, Manfred; Schreiber, Wolfgang G

    2002-04-01

    Myocardial blood flow (MBF) can be quantified using dynamic T1-weighted MRI of diffusible tracers and a mathematical model of underlying vasculature. Quantification of MBF by means of T1- weighted MRI requires knowledge of the arterial input function (AIF). The AIF can be estimated from the left ventricular (LV) cavity. However, dispersion may occur between the LV and the tissue of interest because of the laminar blood flow profiles, branching of venules, and because of stenosis. To evaluate the influence of dispersion on the results of MBF quantification, a simulation study was performed. The dispersion was described as a convolution of the AIF with an exponential residue function. Synthetic tissue and AIF curves were analyzed and the derived parameters fit to the simulated parameters. The results show that an unaccounted dispersion may result in a systematic underestimation of MBF up to approximately 50%. Underestimation increases with increasing dispersion and with increasing MBF. Assuming equal dispersion at rest and during hyperemia, myocardial perfusion reserve (MPR) estimates are also susceptible to underestimation of approximately 20%. An unaccounted dispersion therefore can lead to systematic underestimation of both blood flow and perfusion reserve.

  5. Arterial blood pressure oscillation after active standing up in kidney transplant recipients.

    Science.gov (United States)

    Gerhardt, U; Schäfer, M; Hohage, H

    2000-04-12

    Dynamic arterial blood pressure (FINAPRES) response to active standing up, normally consisting of initial rise, fall and recovery above the baseline (overshoot), was compared with the early steady-state arterial blood pressure level to measure sympathetic vasomotor function in healthy subjects [group 1: n=50, 10 female subjects, age 51+/-2.5 years; weight 78+/-2.3 kg; height 174+/-1.4 cm (mean+/-standard error of the mean)] and in kidney transplant recipients under basal (group 2a: n=50, age 51.7+/-1.7 years; weight 77+/-2.1 kg; height 174+/-1.5 cm) and under high (group 2b: same subjects as in group 2a) cyclosporine A whole blood levels. Furthermore, baroreflex sensitivity and the activity of the generating compounds of the sympathetic nervous systems (Mayer waves) were measured. Systolic and diastolic overshoot values did not differ statistically significant in the present study. In the control subjects, a systolic overshoot of 15.4+/-2.7 mmHg and a diastolic overshoot of 15.2+/-2 mmHg was detected. The systolic overshoot disappeared in 57% of group 2a (-7.1+/-2.7 mmHg; P<0.001) and in 50% of group 2b recipients (-8.0+/-2.7 mmHg; P<0.001). Systolic early steady-state level was not lower in kidney transplant recipients before cyclosporine (baseline+2 mmHg) intake, but after cyclosporine administration (baseline-3 mmHg; controls: baseline+3 mmHg; P<0.05). There was a strong association between the overshoot and steady-state levels (P for chi(2)<0.001, n=150). Overshoot of group 1 levels (r=0.428; P<0.01) and group 2 levels (r=0.714; P<0. 001) correlated to their respective steady-state blood pressure. Furthermore, recipients had reduced baroreceptor sensitivities estimated by sequence analysis as compared to controls (10+/-1 ms/mmHg vs. 7.5+/-1.4 ms/mmHg; P<0.05). Mayer waves amplitudes of the heart rate spectrum were elevated statistically significant in renal transplant recipients (44.4+/-0.2 vs. 43.8+/-2.2 A.U.). In conclusion, baroreceptor reflex

  6. Dependency of cerebral blood flow upon mean arterial pressure in patients with acute bacterial meningitis

    DEFF Research Database (Denmark)

    Møller, Kirsten; Larsen, Fin Stolze; Qvist, Jesper;

    2000-01-01

    OBJECTIVE: Patients with acute bacterial meningitis are often treated with sympathomimetics to maintain an adequate mean arterial pressure (MAP). We studied the influence of such therapy on cerebral blood flow (CBF). DESIGN: Prospective physiologic trial. SETTING: The Department of Infectious...... Diseases, Copenhagen University Hospital, Denmark. PATIENTS: Sixteen adult patients with acute bacterial meningitis. INTERVENTION: Infusion of norepinephrine to increase MAP. MEASUREMENTS: During a rise in MAP induced by norepinephrine infusion, we measured relative changes in CBF by transcranial Doppler...... bacterial meningitis, CBF autoregulation is impaired. With recovery from meningitis, the cerebral vasculature regains the ability to maintain cerebral perfusion at a constant level despite variations in MAP....

  7. Effect of labetalol on cerebral blood flow and middle cerebral arterial flow velocity in healthy volunteers

    DEFF Research Database (Denmark)

    Schroeder, T; Schierbeck, Jens; Howardy, P;

    1991-01-01

    in normotensive subjects. Neither does it affect CO2 reactivity. The uniform results obtained with the two methods suggest TCD as a usable alternative to conventional CBF technique in the assessment of cerebral vasoactivity of various drugs in subjects with a normal cerebral circulation.......The effect of labetalol, a combined alpha- and beta-adrenoceptor antagonist, on the cerebral circulation was investigated in 7 normotensive subjects. Cerebral blood flow (CBF) was measured with the intravenous 133Xe method and mean flow velocity (Vmean) in the middle cerebral artery was determined...

  8. Dual stack black blood carotid artery CMR at 3T: Application to wall thickness visualization

    Directory of Open Access Journals (Sweden)

    Marx Nikolaus

    2009-11-01

    Full Text Available Abstract Background The increasing understanding of atherosclerosis as an important risk factor for the development of acute ischemic events like ischemic stroke has stimulated increasing interest in non-invasive assessment of the structure, composition and burden of plaque depositions in the carotid artery wall. Vessel wall imaging by means of cardiovascular magnetic resonance (CMR is conventionally done by 2D dual inversion recovery (DIR techniques, which often fail in covering large volumes of interest as required in plaque burden assessment. Although the technique has been extended to 2D multislice imaging, its straight extension to 3D protocols is still limited by the prolonged acquisition times and incomplete blood suppression. A novel approach for rapid overview imaging of large sections of the carotid artery wall at isotropic spatial resolutions is presented, which omits excitation of the epiglottis. By the interleaved acquisition of two 3D stacks with the proposed motion sensitized segmented steady-state black-blood gradient echo technique (MSDS the coverage of the carotid artery trees on both sides in reasonable scan times is enabled. Results 10 patients were investigated with the proposed technique and compared to conventional transversal DIR turbo spin and gradient echo approaches centered at the height of the carotid bifurcation. In all MSDS experiments sufficient black-blood contrast could be obtained over the entire covered volumes. The contrast to noise ratio between vessel and suppressed blood was improved by 73% applying the motion sensitizing technique. In all patients the suspicious areas of vessel wall thickening could be clearly identified and validated by the conventional local imaging approach. The average assessable vessel wall segment length was evaluated to be 18 cm. While in 50% of the cases motion artifacts could be appreciated in the conventional images, none were detected for the MSDS technique. Conclusion The

  9. Reducing risk of closed loop control of blood glucose in artificial pancreas using fractional calculus.

    Science.gov (United States)

    Ghorbani, Mahboobeh; Bogdan, Paul

    2014-01-01

    Healthcare costs in the US are among the highest in the world. Chronic diseases such as diabetes significantly contribute to these extensive costs. Despite technological advances to improve sensing and actuation devices, we still lack a coherent theory that facilitates the design and optimization of efficient and robust medical cyber-physical systems for managing chronic diseases. In this paper, we propose a mathematical model for capturing the complex dynamics of blood glucose time series (e.g., time dependent and fractal behavior) observed in real world measurements via fractional calculus concepts. Building upon our time dependent fractal model, we propose a novel model predictive controller for an artificial pancreas that regulates insulin injection. We verify the accuracy of our controller by comparing it to conventional non-fractal models using real world measurements and show how the nonlinear optimal controller based on fractal calculus concepts is superior to non-fractal controllers in terms of average risk index and prediction accuracy.

  10. Simulation of Variable Viscosity and Jeffrey Fluid Model for Blood Flow Through a Tapered Artery with a Stenosis

    Institute of Scientific and Technical Information of China (English)

    Noreen Sher Akbar; S. Nadeem

    2012-01-01

    Non-Newtonian fluid model for blood flow through a tapered artery with a stenosis and variable viscosity by modeling blood as Jeffrey fluid has been studied in this paper. The Jeffrey fluid has two parameters, the relaxation time A1 and retardation time A2. The governing equations are simplified using the case of mild stenosis. Perturbation method is used to solve the resulting equations. The effects of non-Newtonian nature of blood on velocity profile, temperature profile, wall shear stress, shearing stress at the stenotsis throat and impedance of the artery are discussed. The results for Newtonian fluid are obtained as special case from this model.

  11. Heat stress exacerbates the reduction in middle cerebral artery blood velocity during prolonged self-paced exercise.

    Science.gov (United States)

    Périard, J D; Racinais, S

    2015-06-01

    This study examined the influence of hyperthermia on middle cerebral artery mean blood velocity (MCA Vmean). Eleven cyclists undertook a 750 kJ self-paced time trial in HOT (35 °C) and COOL (20 °C) conditions. Exercise time was longer in HOT (56 min) compared with COOL (49 min; P heat appears to have exacerbated the reduction in MCA Vmean, in part via increases in peripheral blood flow and a decrease in arterial blood pressure.

  12. [In vitro study of regulation of shear stress on antithrombogenic potentials of endothelialized polyurethane small diameter artificial blood vessel].

    Science.gov (United States)

    Yang, Zhen; Tao, Jun; Wang, Jiemei; Tu, Chang; Feng, Lianqiang; Pan, Shirong; Ma, Hong

    2008-06-01

    This study was designed to investigate the changes of prostaglandin I2 (PGI2) and nitric oxide (NO) secreted by endothelialized polyurethane small diameter artificial blood vessel. The peripheral blood mononuclear cells of healthy adult were separated and induced into endothelial progenitor cells (EPCs), which were identified by the methods of discrepancy microphage and fluorescent immunology labeling. After the induced cells being seeded on the polyurethane small-diameter artificial vessels, the endothelialized polyurethane small diameter artificial blood vessels were divided into four different experimental groups, including stationary group, low-flow shear stress group (5 dynes/cm2), medium-flow shearstress group (15 dynes/cm2), and high-flow shear stress group (25 dynes/cm2). Then, the levels of 6-ketoprostaglandin F1alpha (6-keto-PGF1alpha) and NO of different time were measured by enzyme-linked immunosorbent assay and nitrate reductase methods. The peripheral blood mononuclear cells differentiated into EPCs. They presented typical "spindie-shaped" appearance, and they were positively labeled by fluorescent acetylated-LDL, lectin, FLK-1 and vWF. Shear stress enhanced the production of NO and 6-keto-PGF1alpha by EPCs in a dose-dependent manner. Therefore, shear stress increases the secretion of NO and PGI2 by EPC, which suggests that shear stress can improve the antithrombogenic potentials of endothelialized polyurethane small diameter artificial blood vessel.

  13. Case with stenosis of internal carotid artery detected as a region of decreased blood flow by Tc-99m HMPAO cerebral blood flow scintigraphy

    Energy Technology Data Exchange (ETDEWEB)

    Hayashida, K.; Nishimura, T.; Uehara, T.; Imakita, S.; Yokota, I.; Ogura, H.; Oka, H.; Hayashi, M.; Kikuchi, H.

    1987-04-01

    Tc-99m hexamethylpropyleneamine oxime (= HMPAO) is expected to be an excellent agent as blood flow tracer of brain because it passes through blood brain barrier and is retained in brain parenchyma for several hours. Tc-99m HMPAO scintigraphy was applied to a patient complaining of transient ischemic attack without neurological findings. Left hemispheric hypoperfusion was detected by Tc-99m HMPAO cerebral blood flow scintigraphy. Although it was normal in CT and MRI, it was proved to be a 99 % stenosis of left internal carotid artery by digital subtraction angiography. Tc-99m HMPAO cerebral blood flow scintigraphy is useful for detecting abnormality of cerebral blood flow.

  14. Hematocrit and mean arterial blood pressure in pre- and postmenopause women

    Directory of Open Access Journals (Sweden)

    Beatriz Y Salazar Vázquez

    2009-05-01

    Full Text Available Beatriz Y Salazar Vázquez1,2, Miguel A Salazar Vázquez3,4, Marcos Intaglietta2, Ulf de Faire5, Bengt Fagrell6, Pedro Cabrales21Facultad de Medicina, 3Department of Physical Chemistry, Universidad Juárez del estado de Durango, Durango, México; 2Department of Bioengineering, University of California, San Diego, La Jolla, CA, USA; 4Department of Pediatrics, Instituto Mexicano del Seguro Social, Durango, México; 5Division of Cardiovascular Epidemiology, Institute of Environmental Medicine, Department of Cardiology, Karolinska Institutet, Solna, Stockholm, Sweden; 6Department of Medicine, Karolinska Institutet at Karolinska Hospital, Solna, Stockholm, SwedenAbstract: The relationship between mean arterial blood pressure (MAP and hematocrit (Hct was studied in pre- and postmenopause women in the city of Durango, Mexico. Premenopause women show a negative trend between parameters that is not statistically significant. MAP and Hct are directly related in postmenopause women (p < 0.01. It is proposed that that this MAP/Hct relationship is in part due to differences in endothelial function where menopause decreases the capacity of the endothelium to respond to increased blood viscosity and shears stress, leading to the increased production of vasodilator mediators to compensate for changes in blood viscosity due to changes in Hct. Comparison with a large group of postmenopause women in the city of Stockholm showed identical trends.Keywords: menopause, endothelial dysfunction, blood viscosity, blood pressure, hematocrit

  15. Peripheral arterial volume distensibility: significant differences with age and blood pressure measured using an applied external pressure.

    Science.gov (United States)

    Zheng, Dingchang; Murray, Alan

    2011-05-01

    A new arterial distensibility measurement technique was assessed in 100 healthy normotensive subjects. Arterial transmural pressures on the whole right arm were reduced with a 50 cm long cuff inflated to 10, 20, 30 and 40 mmHg. The electrocardiogram, and finger and ear photoplethysmograms were recorded simultaneously. Arm pulse propagation time, pulse wave velocity (PWV) and arterial volume distensibility were determined. With a 40 mmHg reduction in transmural pressure, arm pulse propagation time increased from 61 to 83 ms, PWV decreased from 12 to 8 m s(-1) and arterial distensibility increased from 0.102% to 0.232% per mmHg (all P pressures, arterial distensibility was significantly related to resting mean arterial pressure (MAP), diastolic blood pressure (DBP) and age, and for systolic blood pressure at 30 and 40 mmHg (all P pressure, arterial distensibility fell by 54% for a MAP increase from 75 to 105 mmHg, 57% for a DBP increase from 60 to 90 mmHg and 47% for an age increase from 20 to 70 years. These changes were more than double than those without cuff pressure. Our technique showed that systemic volume distensibility of the peripheral arm artery reduced with age, with a greater effect at higher external and lower transmural pressures.

  16. Sickle Cell Anemia: Reference Values of Cerebral Blood Flow Determined by Continuous Arterial Spin Labeling MRI

    Science.gov (United States)

    Arkuszewski, M.; Krejza, J.; Chen, R.; Melhem, E.R.

    2013-01-01

    Sickle cell anemia (SCA) is a chronic illness associated with progressive deterioration in patients' quality of life. The major complications of SCA are cerebrovascular accidents (CVA) such as asymptomatic cerebral infarct or overt stroke. The risk of CVA may be related to chronic disturbances in cerebral blood flow (CBF), but the thresholds of “normal” steady-state CBF are not well established. The reference tolerance limits of CBF can be useful to estimate the risk of CVA in asymptomatic children with SCA, who are negative for hyperemia or evidence of arterial narrowing. Continuous arterial spin labeling (CASL) MR perfusion allows for non-invasive quantification of global and regional CBF. To establish such reference tolerance limits we performed CASL MR examinations on a 3-Tesla MR scanner in a carefully selected cohort of 42 children with SCA (mean age, 8.1±3.3 years; range limits, 2.3–14.4 years; 24 females), who were not on chronic transfusion therapy, had no history of overt stroke or transient ischemic attack, were free of signs and symptoms of focal vascular territory ischemic brain injury, did not have intracranial arterial narrowing on MR angiography and were at low risk for stroke as determined by transcranial Doppler ultrasonography. PMID:23859242

  17. Sickle cell anemia: reference values of cerebral blood flow determined by continuous arterial spin labeling MRI.

    Science.gov (United States)

    Arkuszewski, M; Krejza, J; Chen, R; Melhem, E R

    2013-04-01

    Sickle cell anemia (SCA) is a chronic illness associated with progressive deterioration in patients' quality of life. The major complications of SCA are cerebrovascular accidents (CVA) such as asymptomatic cerebral infarct or overt stroke. The risk of CVA may be related to chronic disturbances in cerebral blood flow (CBF), but the thresholds of "normal" steady-state CBF are not well established. The reference tolerance limits of CBF can be useful to estimate the risk of CVA in asymptomatic children with SCA, who are negative for hyperemia or evidence of arterial narrowing. Continuous arterial spin labeling (CASL) MR perfusion allows for non-invasive quantification of global and regional CBF. To establish such reference tolerance limits we performed CASL MR examinations on a 3-Tesla MR scanner in a carefully selected cohort of 42 children with SCA (mean age, 8.1±3.3 years; range limits, 2.3-14.4 years; 24 females), who were not on chronic transfusion therapy, had no history of overt stroke or transient ischemic attack, were free of signs and symptoms of focal vascular territory ischemic brain injury, did not have intracranial arterial narrowing on MR angiography and were at low risk for stroke as determined by transcranial Doppler ultrasonography.

  18. Effect of Algerian Varieties Dates on Glycemic, Arterial Blood Pressure and Satiety Responses

    Directory of Open Access Journals (Sweden)

    Gourchala Freha, Mihoub Fatma, Derradj Meriem,\tHenchiri Cherifa

    2016-04-01

    Full Text Available The purpose of our study is to determine the Glycemic Indexes (GIsof three Algerians varieties of dates in healthy subjects, evaluate the satiety and effect on arterial pressure after their consumption. We have first documented the chemical composition of the dates. 10 healthy subjects consumed the dates (carbohydrates content of 50 g in order to determine the GIs. The responses of glycaemia were monitored during two hours after the dates taking and compared to the reference glucose. In a randomized trial, 20 healthy adults consumed the dates after 12h of fast. We reported the level of satiety on a Visual Analog Scale for 2h further to the ingestion of the dates. Furthermore, 28 normotensive and 45 hypertensive individuals ingested the three varieties in randomized order during 21 days to assess their impact on the Pressure Arterial Systolic (PAS and Pressure Arterial Diastolic (PAD. We noted significant differences (p<0.05 for the different fractions of sugars, soluble fibers, polyphenols, K+, Mg2+. The low GIs are denoted among 44.31-52.35, deducting a moderate impact on blood glucose level. The dates reduced hunger and increased satiety. Our varieties studied following their ingestion induced a significant hypotensive activity (p<0.05on the PAS and, PAD from hypertensive subjects.

  19. Numerical Study of Turbulent Pulsatile Blood Flow through Stenosed Artery Using Fluid-Solid Interaction

    Directory of Open Access Journals (Sweden)

    Mehdi Jahangiri

    2015-01-01

    Full Text Available The turbulent pulsatile blood flow through stenosed arteries considering the elastic property of the wall is investigated numerically. During the numerical model validation both standard k-ε model and RNG K-ε model are used. Compared with the RNG K-ε model, the standard K-ε model shows better agreement with previous experimental results and is better able to show the reverse flow region. Also, compared with experimental data, the results show that, up to 70% stenosis, the flow is laminar and for 80% stenosis the flow becomes turbulent. Assuming laminar or turbulent flow and also rigid or elastic walls, the results are compared with each other. The investigation of time-averaged shear stress and the oscillatory shear index for 80% stenosis show that assuming laminar flow will cause more error than assuming a rigid wall. The results also show that, in turbulent flow compared with laminar flow, the importance of assuming a flexible artery wall is more than assuming a rigid artery wall.

  20. The analysis of MHD blood flows through porous arteries using a locally modified homogenous nanofluids model.

    Science.gov (United States)

    Akbarzadeh, Pooria

    2016-05-12

    In this paper, magneto-hydrodynamic blood flows through porous arteries are numerically simulated using a locally modified homogenous nanofluids model. Blood is taken into account as the third-grade non-Newtonian fluid containing nanoparticles. In the modified nanofluids model, the viscosity, density, and thermal conductivity of the solid-liquid mixture (nanofluids) which are commonly utilized as an effective value, are locally combined with the prevalent single-phase model. The modified governing equations are solved numerically using Newton's method and a block tridiagonal matrix solver. The results are compared to the prevalent nanofluids single-phase model. In addition, the efficacies of important physical parameters such as pressure gradient, Brownian motion parameter, thermophoresis parameter, magnetic-field parameter, porosity parameter, and etc. on temperature, velocity and nanoparticles concentration profiles are examined.

  1. Investigation of tissue oxygenation by in vivo laser-induced photodissociation of cutaneous arterial blood oxyhemoglobin

    Science.gov (United States)

    Asimov, M. M.; Korolevich, A. N.

    2008-06-01

    A novel method of direct control of local tissue oxygenation based on laser-induced photodissociation of oxyhemoglobin in cutaneous blood vessels is discussed. New technology in selective and local increase of the concentration of free molecular oxygen in tissue that enhances metabolism of cells is demonstrated. Direct in vivo measurements of the tissue oxygen tension are carried out on human skin. Kinetics of oxygen tension in tissue is investigated under the effect of He-Ne laser radiation at the power of 1mW relatively to initial value of tissue oxygen tension. The results of experimental study the kinetics of oxygen distribution into tissue from arterial blood is presented. Biomedical applications of proposed new technology in laser therapy of pathologies where elimination of local tissue hypoxia is critical are discussed.

  2. Oscillometric blood pressure measurement: a simple method in screening for peripheral arterial disease

    DEFF Research Database (Denmark)

    Mehlsen, Jesper; Wiinberg, Niels; Bruce, Christopher

    2008-01-01

    Blood pressure at the ankle level is a reliable indicator of peripheral arterial disease (PAD) and the ankle brachial index (ABI) is a useful non-invasive screening tool for the early detection of atherosclerosis. In the first part of the study, systolic blood pressures obtained by oscillometry......, the oscillometry showed a positive predictive value of 47%. The presence of PAD was significantly correlated to exercise related leg pain, a diagnosis of hypertension and smoking, whereas no correlation could be found with a diagnosis of heart disease, stroke, or with the presence of diabetes. The prevalence...... of PAD was sufficiently high in subjects over the age of 60 years to warrant screening. The ankle brachial index based on measurements with an oscillometric device was shown reliable in the exclusion of PAD, thereby fulfilling an important criterion for the use in screening....

  3. "Stolen" blood flow: effect of an open arterial filter purge line in a simulated neonatal CPB model.

    Science.gov (United States)

    Wang, Shigang; Miller, Akemi; Myers, John L; Undar, Akif

    2008-01-01

    The purpose of this study was to evaluate the effect of different flow rates and pressures on the degree of shunting of blood flow by the arterial filter purge line in a simulated neonatal cardiopulmonary bypass circuit. The circuit was primed with heparinized bovine blood (hematocrit 24%) and postfilter pressure was varied from 60-180 mm Hg (20 mm Hg increments) using a Hoffman clamp. Trials were conducted at flow rates ranging from 200-600 ml/min (100 ml/min increments). During trials conducted at a postfilter pressure of 60 mm Hg, 42.6% of blood flow was shunted through the purge line at a flow rate of 200 ml/min, whereas only 12.8% of flow was diverted at a flow rate 600 ml/min. During trials conducted at a postfilter pressure of 180 mm Hg, 82.8% of blood flow at 200 ml/min and 25.9% of blood flow at 600 ml/min was diverted through the open arterial purge line. The results of this study confirm that a significant amount of flow is diverted away from the patient when the arterial purge line is open. Shunting of blood flow through the arterial purge line could result in less effective tissue perfusion, particularly at low flow rates and high postfilter pressures. To minimize hypoperfusion injury, a flow probe (distal to the arterial filter) may be used to monitor real-time arterial flow in the setting of an open arterial filter purge line.

  4. Mortality risk is dose-dependent on the number of packed red blood cell transfused after coronary artery bypass graft

    OpenAIRE

    dos Santos, Antônio Alceu; de Sousa, Alexandre Gonçalves; Piotto, Raquel Ferrari; Pedroso, Juan Carlos Montano [UNIFESP

    2013-01-01

    Introduction Transfusions of one or more packed red blood cells is a widely strategy used in cardiac surgery, even after several evidences of increased morbidity and mortality. The world's blood shortage is also already evident. Objective To assess whether the risk of mortality is dose-de>pendent on the number of packed red blood cells transfused after coronary artery bypass graft. Methods Between June 2009 and July 2010, were analyzed 3010 patients: transfused and non-transfused. Transfused ...

  5. Arterial blood gas analysis and electrolyte determination in neonates with asphyxia

    Institute of Scientific and Technical Information of China (English)

    Zi-Mei Sun

    2015-01-01

    Objective:To explore the value of arterial blood gas analysis and electrolyte determination in the diagnosis of neonatal asphyxia.Methods: A total of 100 neonates with asphyxia who were admitted in our department from March, 2013 to March, 2014 were included in the study and divided into the mild asphyxia group and the severe asphyxia group according to Apgar scoring. Moreover, 50 normal neonates were served as the control group and used for comparative analysis. AVL blood-gas analyzer was used to detect the levels of pH, PaO2, HCO3-, BE, PaCO2, K+, Na+, Cl-, and Ca2+.Results:The concentrations of pH, PaO2, HCO3-, and BE in the severe asphyxia group were significantly lower than those in the mild asphyxia group and the control group, while PaCO2 level was significantly higher than that in the mild asphyxia group and the control group. The comparison of the various indicators between the control group and the mild asphyxia group was not statistically significant. The comparison of serum K+, Na+,and Cl- levels among the control group, the mild asphyxia group, and the severe asphyxia group was not statistically significant. The serum Ca2+ level in the severe asphyxia group was significantly lower than that in the mild asphyxia group and the control group, while the comparison between the mild asphyxia group and the control group was also statistically significant.Conclusions:Blood gas analysis and electrolyte determination to the arterial blood in neonates can compensate for the insufficiency of Apgar scoring and provide an objective evidence for the diagnosis of neonatal asphyxia and the estimation of severity degree. Clinical combination with Apgar scoring is of great significance in enhancing the diagnosis of neonatal asphyxia and the accuracy of severity evaluation.

  6. The Fatty Acid Composition of Blood Plasma and Arterial Wall in Atherosclerosis

    Directory of Open Access Journals (Sweden)

    Alexander N. Osipenko

    2012-12-01

    Full Text Available The aim of this study was to assess the fatty acid balance in the blood plasma, in the fragments of the intact vessels and the vessels showing signs of atherosclerosis.Material and Methods: The article presents the results of the examination of the blood plasma samples of patients with coronary heart disease and coronary atherosclerosis. The control group consisted of 16 healthy individuals. Also, the fragments of the abdominal aorta and the common carotid artery with varying degrees of atherosclerotic lesions were studied. Fatty acid analysis was conducted using capillary gas-liquid chromatography. Results: A reduction in the relative linoleic acid level with an increase in almost all the saturated fatty acids and polyunsaturated dihomo-γ-linolenic acid in the plasma was noted in patients with coronary heart disease and atherosclerosis. The relationships between certain fatty acids in patients with atherosclerosis and myocardial ischemia showed changes. In patients with atherosclerosis, a marked imbalance was observed between the monounsaturated and correspondingly the saturated fatty acids (with the same number of carbon atoms in the abdominal aorta with significant atherosclerotic lesions, as well as in the intact common carotid arteries. These disorders are probably related to the relatively low content of the linoleic acid in the blood plasma. The reasons for the increased activity of the fatty acid synthase in vessels with significant atherosclerotic lesions are described. It is concluded that most of the fatty acids of the plaque were formed due to the synthetic processes in the smooth muscle cells, and not as a result of their intake from the blood plasma.

  7. Experimental investigation of the flow of a blood analogue fluid in a replica of a bifurcated small artery.

    Science.gov (United States)

    Anastasiou, A D; Spyrogianni, A S; Koskinas, K C; Giannoglou, G D; Paras, S V

    2012-03-01

    The scope of this work is to study the pulsatile flow of a blood mimicking fluid in a micro channel that simulates a bifurcated small artery, in which the Fahraeus-Lindqvist effect is insignificant. An aqueous glycerol solution with small amounts of xanthan gum was used for simulating viscoelastic properties of blood and in vivo flow conditions were reproduced. Local flow velocities were measured using micro Particle Image Velocimetry (μ-PIV). From the measured velocity distributions, the wall shear stress (WSS) and its variation during a pulse were estimated. The Reynolds numbers employed are relatively low, i.e. similar to those prevailing during blood flow in small arteries. Experiments both with a Newtonian and a non-Newtonian fluid (having asymptotic viscosity equal to the viscosity of the Newtonian one) proved that the common assumption that blood behaves as a Newtonian fluid is not valid for blood flow in small arteries. It was also shown that the outer wall of the bifurcation, which is exposed to a lower WSS, is more predisposed to atherosclerotic plaque formation. Moreover, this region in small vessels is shorter than the one in large arteries, as the developed secondary flow decays faster. Finally, the WSS values in small arteries were found to be lower than those in large ones.

  8. Isobolographic analysis of the interaction between fenoldopam and levodopa on arterial blood pressure of the rat.

    Science.gov (United States)

    Quevedo, M; Prieto, J C; Miranda, H F; Pinardi, G

    2000-09-01

    Fenoldopam (FD) and levodopa (LD) injected intravenously in rats in a noncumulative schedule induced dose-dependent reductions in mean arterial blood pressure. The doses that induced a 50% reduction in the initial control mean arterial pressure (referred as ED50) were calculated by linear regression analysis of the corresponding parallel dose-response curves and were 0.88 and 0.068 mg/kg, respectively. The interaction between the effects of FD and LD on pressure reduction was evaluated by simultaneous administration of different fixed ratios of FD and LD (16:1) and obtaining a dose-response curve. An isobolographic analysis was then performed, which showed that the experimental point for the effect of the simultaneous administration of FD and LD was significantly different from the theoretically calculated additive point, denoting supradditivity. It was concluded that the effect of the combination of FD and LD on mean blood pressure reduction was synergic and was probably due to an activation of D1 vascular receptors by both drugs, in conjunction with an activation of beta2 adrenoceptors by LD and a blocking action of FD on postsynaptic alpha1-adrenoceptors.

  9. Recent trends on the stent research for blood arteries by bibliometric analysis.

    Science.gov (United States)

    Ahn, Sejung; Sung, Jung-Suk; Choi, Brad; Kim, Hackjoo; Sung, Yong Kiel

    2014-01-01

    The research trends on stent for blood arteries are reviewed by bibliometric analysis using 7,790 journal articles published from 1986 to 2013 of the Web of Science database. The bibliometric indicators are applied to analyze the journal article data, which are simple number of publications for selecting key players, citation indicators for measuring qualitative research performance, collaboration indicators for figuring out the degree of international collaboration and keyword mapping for identifying the research trends. The studies of stent for blood arteries are investigated on the basis of the analysis by countries, institutions and topic changing. The leading countries and institutions published many high-quality journal articles with strong international collaboration. In this report, the current status and future of research trends are clearly revealed from the periodic topic changing analysis. The keywords such as 'drug eluting stent', 'stent coated with new polymers' and 'drug delivery systems' have come into the recent stent-related research, which means lots of efforts are under way to overcome the present limitations of the research.

  10. Effects of prostaglandin analogs on blood flow velocity and resistance in the ophthalmic artery of rabbits

    Directory of Open Access Journals (Sweden)

    Amália Turner Giannico

    2016-02-01

    Full Text Available ABSTRACT Purpose: The aim of this study was to investigate the effects of prostaglandin analogs on blood flow in the ophthalmic artery of clinically healthy rabbits. Methods: Fifty-five clinically healthy New Zealand white rabbits were divided into six groups, and the left eyes were treated for four weeks with the preservative benzalkonium chloride (BAK only or a topical formulation of different prostaglandin analogs (bimatoprost BAK, tafluprost BAK-free, travoprost BAK, travoprost POLYQUAD, and latanoprost BAK. Color Doppler imaging was performed before and after the treatments. The mean values of the peak systolic velocity (PSV and end diastolic velocity and the resistive index (RI were calculated. Statistical analysis was performed to compare the differences pre- and post-treatment for each drug and post-treatment among the drugs. Results: The prostaglandin analogs did not affect PSV. Bimatoprost BAK, travoprost POLYQUAD, and latanoprost BAK did not change RI. Tafluprost BAK-free and travoprost BAK therapy resulted in similar reductions in RI. No significant differences pre- and post-treatment were found when BAK was administered alone. Conclusion: The prostaglandin analogs tafluprost BAK-free and travoprost BAK improved blood flow in the ophthalmic artery in healthy New Zealand white rabbits, which suggests that these drugs enhance the prevention of the progression the progression of glaucoma.

  11. A model for investigating the control of muscle blood flow: the masseteric artery in conscious rabbits.

    Science.gov (United States)

    Roatta, S; Mohammed, M; Turturici, M; Milano, L; Passatore, M

    2010-09-01

    The complex interplay of neural, metabolic, myogenic and mechanical mechanisms that regulate blood flow in skeletal muscle (MBF) is still incompletely understood. For the first time, a method is presented for high time-resolution recording of MBF from a purely muscular artery in physiological conditions. Ultrasound perivascular flow probes were implanted (n = 15) mono- or bilaterally around the masseteric branch of the facial artery in nine rabbits and tested up to 16 days after implant. Reliable and stable recordings were achieved in 50% of implants. Blood flow was observed to increase from a resting level of 0.2-0.3 ml min(-1) up to 4.0-6.0 ml min(-1) during spontaneous masticatory activity. In addition, within single masticatory cycles marked back flow transients could be observed (peak flow = -10 ml min(-1)) during powerful masticatory strokes but not during mild mastication. The possibility of (1) surgically removing the sympathetic supply to the relevant vascular bed and of (2) bilaterally monitoring the perfusion of masseter muscles thus allowing to use one side as control side for different types of interventions makes this model a useful tool for disentangling the different mechanisms involved in the control of MBF.

  12. The effect of time from last food intake on arterial blood gases: Implication on reference values

    Directory of Open Access Journals (Sweden)

    Zahedpour Anaraki M

    2000-08-01

    Full Text Available Arterial blood gas parameters were analyzed in forty-nine healthy persons (31 males, 18 females to detemine reference values fo these parameters and their relation to the time from last food intake to arterial puncture (T. The mean ± standard deviation of arterial oxygen pressure, arterial carbon dioxide pressure and pH at core body temperature were 84.4±7.0 mmHg (Male: 83.0±6.5, Female: 86.7±73, 37.7±2.8 mmHg (Male: 38.5±2.7, Female: 36.2±2.4 respectively 7.41±0.02 (Male: 7.41±0.02 Female: 7.42±0.03. the mean PCO2 was lower in comparison with most of the studies at sea level. The difference between males and females was significant in PCO2 and PH (P=0.004, P=0.02 respectively but in was not significant in PO2 (P=0.07. The PCO2 and pH had no statistically significant relatioship with age (P=0.42, P=0.25 respectively. The relationship between Po2 with age, PCO2 and T was significant (P=0.02, P=0.017, and P=0.019 respectively. The best linear predictive equation was: Po2= 1.28 AO2-29.4 for T10hours Þ AO2 = 0.21(Baro-47 – (1.2PCO2

  13. Longitudinal perspective on the conundrum of central arterial stiffness, blood pressure, and aging.

    Science.gov (United States)

    Scuteri, Angelo; Morrell, Christopher H; Orrù, Marco; Strait, James B; Tarasov, Kirill V; Ferreli, Liana Anna Pina; Loi, Francesco; Pilia, Maria Grazia; Delitala, Alessandro; Spurgeon, Harold; Najjar, Samer S; AlGhatrif, Majd; Lakatta, Edward G

    2014-12-01

    The age-associated increase in arterial stiffness has long been considered to parallel or to cause the age-associated increase in blood pressure (BP). Yet, the rates at which pulse wave velocity (PWV), a measure of arterial stiffness, and BP trajectories change over time within individuals who differ by age and sex have not been assessed and compared. This study determined the evolution of BP and aortic PWV trajectories during a 9.4-year follow-up in >4000 community-dwelling men and women of 20 to 100 years of age at entry into the SardiNIA Study. Linear mixed effects model analyses revealed that PWV accelerates with time during the observation period, at about the same rate over the entire age range in both men and women. In men, the longitudinal rate at which BP changed over time, however, did not generally parallel that of PWV acceleration: at ages>40 years the rates of change in systolic BP (SBP) and pulse pressure (PP) increase plateaued and then declined so that SBP, itself, also declined at older ages, whereas PP plateaued. In women, SBP, diastolic BP, and mean BP increased at constant rates across all ages, producing an increasing rate of increase in PP. Therefore, increased aortic stiffness is implicated in the age-associated increase in SBP and PP. These findings indicate that PWV is not a surrogate for BP and that arterial properties other than arterial wall stiffness that vary by age and sex also modulate the BP trajectories during aging and lead to the dissociation of PWV, PP, and SBP trajectories in men.

  14. The impact of capillary dilation on the distribution of red blood cells in artificial networks.

    Science.gov (United States)

    Schmid, Franca; Reichold, Johannes; Weber, Bruno; Jenny, Patrick

    2015-04-01

    Recent studies suggest that pericytes around capillaries are contractile and able to alter the diameter of capillaries. To investigate the effects of capillary dilation on network dynamics, we performed simulations in artificial capillary networks of different sizes and complexities. The unequal partition of hematocrit at diverging bifurcations was modeled by assuming that each red blood cell (RBC) enters the branch with the faster instantaneous flow. Network simulations with and without RBCs were performed to investigate the effect of local dilations. The results showed that the increase in flow rate due to capillary dilation was less when the effects of RBCs are included. For bifurcations with sufficient RBCs in the parent vessel and nearly equal flows in the branches, the flow rate in the dilated branch did not increase. Instead, a self-regulation of flow was observed due to accumulation of RBCs in the dilated capillary. A parametric study was performed to examine the dependence on initial capillary diameter, dilation factor, and tube hematocrit. Furthermore, the conditions needed for an efficient self-regulation mechanism are discussed. The results support the hypothesis that RBCs play a significant role for the fluid dynamics in capillary networks and that it is crucial to consider the blood flow rate and the distribution of RBCs to understand the supply of oxygen in the vasculature. Furthermore, our results suggest that capillary dilation/constriction offers the potential of being an efficient mechanism to alter the distribution of RBCs locally and hence could be important for the local regulation of oxygen delivery.

  15. Early development of arterial spin labeling to measure regional brain blood flow by MRI.

    Science.gov (United States)

    Koretsky, Alan P

    2012-08-15

    Two major avenues of work converged in the late 1980's and early 1990's to give rise to brain perfusion MRI. The development of anatomical brain MRI quickly had as a major goal the generation of angiograms using tricks to label flowing blood in macroscopic vessels. These ideas were aimed at getting information about microcirculatory flow as well. Over the same time course the development of in vivo magnetic resonance spectroscopy had as its primary goal the assessment of tissue function and in particular, tissue energetics. For this the measurement of the delivery of water to tissue was critical for assessing tissue oxygenation and viability. The measurement of the washin/washout of "freely" diffusible tracers by spectroscopic based techniques pointed the way for quantitative approaches to measure regional blood flow by MRI. These two avenues came together in the development of arterial spin labeling (ASL) MRI techniques to measure regional cerebral blood flow. The early use of ASL to measure brain activation to help verify BOLD fMRI led to a rapid development of ASL based perfusion MRI. Today development and applications of regional brain blood flow measurements with ASL continues to be a major area of activity.

  16. Time course and recovery of arterial blood gases during exacerbations in adults with Cystic Fibrosis.

    LENUS (Irish Health Repository)

    Waterhouse, D F

    2012-02-01

    INTRODUCTION: Hypoxia and hypercapnia are closely linked to morbidity and mortality in patients with Cystic Fibrosis (CF). The aims of this study were to describe the changes in blood gases during and following an acute pulmonary exacerbation in adults with CF. METHODS: We performed a prospective observational study of patients with CF admitted for management of an acute exacerbation. Blood gas and spirometric analysis was performed on admission, throughout the treatment period, and 31 days after discharge (day 45). RESULTS: At presentation, eight of nineteen patients had evidence of either hypoxia (PaO(2)<8 kPa) and\\/or hypercapnia (PaCO(2)>6.6 kPa). Blood gas parameters stabilized following two weeks of intravenous antibiotic therapy, with little difference evident in between treatment completion and subsequent review following discharge. Hypercapnia reversed in three patients, with persistent hypercapnia evident in two patients. CONCLUSION: In our study group, hypoxemia and hypercapnia were frequently observed at presentation of the acute exacerbation. Blood gases stabilized following two weeks of intravenous antibiotic therapy, with arterial PCO(2) one month following hospital discharge generally similar to that at time of discharge.

  17. Effects of GSM 900 MHz on middle cerebral artery blood flow assessed by transcranial Doppler sonography.

    Science.gov (United States)

    Ghosn, Rania; Thuróczy, György; Loos, Nathalie; Brenet-Dufour, Valérie; Liabeuf, Sophie; de Seze, René; Selmaoui, Brahim

    2012-12-01

    Mobile phone use has increased worldwide but its possible effects on the brain remain unclear. The aim of the present study was to investigate the effect of acute exposure to a radio frequency electromagnetic field (RF EMF) generated by a mobile phone operating in the Global System for Mobile Communication (GSM) 900 MHz on cerebral blood flow. Twenty-nine volunteers attended two experimental sessions: a sham exposure session and a real exposure session in a cross-over double-blind study in which a mobile phone was positioned on the left side of the head. In one session, the mobile phone was operated without RF radiation (sham phone) and in the other study it was operated with RF radiation (real phone) for 20 min. Thus, each subject served as its own control. Middle cerebral artery blood flow was monitored noninvasively by transcranial Doppler sonography to measure middle cerebral artery blood flow velocity. Pulsatility index and resistance index were also evaluated. A voluntary breath holding physiological test was carried out as a positive control for testing cerebral vasoreactivity. Hemodynamic variables were recorded and analyzed before, during and after mobile phone exposure. No significant changes were detected in studied variables in middle cerebral arteries during sham or real exposure. In the exposed side the cerebral blood flow velocity, the pulsatility index and the resistance index during sham and real exposure were respectively: [61.9 ± 1.3, 61.7 ± 1.3 cm/s (P = 0.89)]; [0.93 ± 0.03, 0.90 ± 0.02 (P = 0.84)] and [0.58 ± 0.01, 0.58 ± 0.01 (P = 0.96)] at baseline; and [60.6 ± 1.3, 62 ± 1.6 cm/s (P = 0.40)]; [0.91 ± 0.03, 0.87 ± 0.03 (P = 0.97)]; [0.57 ± 0.01, 0.56 ± 0.01 (P = 0.82)] after 20 min of exposure. Twenty minutes of RF exposure to a mobile phone does not seem to affect the cerebral circulation.

  18. Correlation between arterial and venous blood gas analysis parameters in patients with acute exacerbation of chronic obstructive pulmonary disease

    Directory of Open Access Journals (Sweden)

    Novović Miloš

    2012-01-01

    Full Text Available Introduction. Arterial blood gas (ABG analyses have an important role in the assessment and monitoring of the metabolic and oxygen status of patients with acute exacerbation of chronic obstructive pulmonary disease (COPD. Arterial puncture could have a lot of adverse effects, while sampling of venous blood is simpler and is not so invasive. Objective. The aim of this study was to evaluate whether venous blood gas (VBG values of pH, partial pressure of carbon dioxide (PCO2, partial oxygen pressure (PO2, bicarbonate (HCO3, and venous and arterial blood oxygen saturation (SO2 can reliably predict ABG levels in patients with acute exacerbation of COPD. Methods. Forty-seven patients with a prior diagnosis of COPD were included in this prospective study. The patients with acute exacerbation of this disease were examined at the General Hospital EMS Department in Prijepolje. ABG samples were taken immediately after venous sampling, and both were analyzed. Results. The Pearson correlation coefficients between arterial and venous parameters were 0.828, 0.877, 0.599, 0.896 and 0.312 for pH, PCO2, PO2, HCO3 and SO2, respectively. The statistically significant correlation between arterial and venous pH, PCO2 and HCO3, values was found in patients with acute exacerbation of COPD (p<0.001. Conclusion. When we cannot provide arterial blood for analysis, venous values of the pH, Pv,CO2 and HCO3 parameters can be an alternative to their arterial equivalents in the interpretation of the metabolic status in patients with acute exacerbation of COPD, while the values of venous Pv,O2 and Sv,O2 cannot be used as predictors in the assessment of oxygen status of such patients.

  19. Related research of blood glucose, blood lipid and serum cystatin C and lower-extremity arterial disease in type 2 diabetic mellitus

    Institute of Scientific and Technical Information of China (English)

    Juan Zeng; Jie Ou; Yun-Mei He; Chun-Yu Cai

    2016-01-01

    Objective:To explore the relationship between levels of blood glucose, blood lipid and serum cystatin C and lower-extremity arterial disease in type 2 diabetic mellitus so as to provide the basis for the prevention and treatment of the disease.Methods:A total of 240 cases of patients with type 2 diabetic mellitus receiving physical examinations in our hospital from March 2014 to March 2015 were selected and divided into three groups. The control group was consisted of type 2 diabetes patients without lower-extremity arterial disease, the observation group 1 included type 2 diabetes patients with mild or moderate lower-extremity arterial disease, and the observation group 2 was formed by type 2 diabetes patients with severe lower-extremity arterial disease. Each group contained 80 cases. Then, the heights, weights, waist and hip circumferences of patients in the three groups were determined and the body mass index (BMI) and waist to hip ratio (WHR) were calculated; the fasting blood glucose (FBG), fasting insulin (FINS), insulin resistance index (HOMA-IR), 2 h postprandial blood glucose (2 h PG) and glycosylated hemoglobin (HBA1c) in two groups were detected; and the levels of serum total cholesterol(TC), triglyceride (TG), low density lipoprotein cholesterol (LDL-C), high density lipoprotein cholesterol (HDL-C), apolipoprotein A1 (apoA1), apolipoprotein B (apoB) and cystatin C (CysC) in two groups were also tested.Results:Compared with the control group, the WHR, FBG, HOMA-IR, 2 h PG, HBA1c, LDL-C, apoB and CysC all increased significantly, and the differences were statistically significant. Besides, there were statistically significances existing between the observation groups 1 and 2. What’s more, the serum levels of TC, HDL-C, TG and apoA1 in the observation groups were not significantly different from those of the control group.Conclusions: There is a close relationship between blood glucose, blood lipid, serum cystatin C level and lower-extremity arterial

  20. A Combination of Constitutive Damage Model and Artificial Neural Networks to Characterize the Mechanical Properties of the Healthy and Atherosclerotic Human Coronary Arteries.

    Science.gov (United States)

    Karimi, Alireza; Rahmati, Seyed Mohammadali; Sera, Toshihiro; Kudo, Susumu; Navidbakhsh, Mahdi

    2017-02-02

    It has been indicated that the content and structure of the elastin and collagen of the arterial wall can subject to a significant alteration due to the atherosclerosis. Consequently, a high tissue stiffness, stress, and even damage/rupture are triggered in the arterial wall. Although many studies so far have been conducted to quantify the mechanical properties of the coronary arteries, none of them consider the role of collagen damage of the healthy and atherosclerotic human coronary arterial walls. Recently, a fiber family-based constitutive equation was proposed to capture the anisotropic mechanical response of the healthy and atherosclerotic human coronary arteries via both the histostructural and uniaxial data. In this study, experimental mechanical measurements along with histological data of the healthy and atherosclerotic arterial walls were employed to determine the constitutive damage parameters and remodeling of the collagen fibers. To do this, the preconditioned arterial tissues were excised from human cadavers within 5-h postmortem, and the mean angle of their collagen fibers was precisely determined. Thereafter, a group of quasistatic axial and circumferential loadings were applied to the arterial walls, and the constrained nonlinear minimization method was employed to identify the arterial parameters according to the axial and circumferential extension data. The remodeling of the collagen fibers during the tensile test was also predicted via Artificial Neural Networks algorithm. Regardless of loading direction, the results presented a noteworthy load-bearing capability and stiffness of the atherosclerotic arteries compared to the healthy ones (P < 0.005). Theoretical fiber angles were found to be consistent with the experimental histological data with less than 2 and 5° difference for the healthy and atherosclerotic arterial walls, respectively. The pseudoelastic damage model data were also compared with that of the experimental data, and

  1. The Correlation between Systolic Blood Pressure Measured by Return to Flow Versus Systolic Blood Pressure Measured by Arterial Catheter in the Adult Anesthetized Patient.

    Science.gov (United States)

    1986-12-01

    a U-tube and mercury manometer for other research, he did not use it to measure arterial blood pressure (30). It was almost a century 34 N N 35 later...use of this mercury manometer decreased the size of the measuring apparatus more than 27 times (30). Carl Ludwig made an important contribution to...direct measurement of blood pressure in 1847 when he added a i graphic recording device to the mercury manometer . This eliminated observer error and

  2. Results of ambulatory arterial blood pressure monitoring in children with obesity

    Directory of Open Access Journals (Sweden)

    Faruk Öktem

    2010-12-01

    Full Text Available Objectives: The relationship between obesity and essential hypertension is well known. In this study, we aimed to evaluate ambulatory arterial blood pressure monitoring of obese and non-obese children who had similar demographic characteristics.Materials and methods: Seventy one children and adolescents (n=39 obesity, n=32 controls were studied. Blood pressure of the children were measured by 24 hour ambulatory blood pressure monitoring device.Results: Obese children had significantly higher mean blood pressure values (systolic 121.9±11.7 mmHg, diastolic 70.2±5.3 mmHg than control subjects (systolic 109.3±6.7 mmHg, diastolic 65.1±4.6 mmHg, p0.05. Blood pressure load was found to be increased in obese children compared to the controls (%13.6±12.9 and %2.6±3.4, respectively; p<0.05. Serum total cholesterol and LDL-cholesterol levels of obese children (181.1±33.4 and 131.1±23.1mg/dl were significantly higher than those of the controls (134.3±11.1 and 103.3±14.2 mg/dl, p<0.05.Conclusions: Obesity in children and adolescents should not be regarded as variations of normality, but as abnormality with an extremely high risk for the development of hypertension and hyperlipidemia in adulthood.

  3. Effects of renal artery stenting on renal function and blood pressure in patients with atherosclerotic renovascular disease

    Institute of Scientific and Technical Information of China (English)

    张奇; 沈卫峰; 张瑞岩; 张建盛; 胡健; 张宪

    2003-01-01

    Objective To study the effects of percutaneous renal artery intervention on renal function and blood pressure in patients with renal artery stenosis. Methods Eighty-seven patients with severe uni- or bi-lateral renal artery stenosis (luminal diameter narrowing ≥70%) and clinical hypertension received renal artery stenting between January 2002 and December 2002. The changes in blood pressure and serum creatinine level and creatinine clearance (CCr) 48 hours after intervention and during 6 months of follow-up were assessed.Results Renal stenting was performed in 98 stenotic arteries of 87 patients, and the procedural success rate was 100%. Serum creatinine level was slightly elevated from (176±21) μmol/L to (179±11) μmol/L (P=0.15) 48 hours after the procedure, but significantly decreased to (149±15) μmol/L at 6 months (P<0.001). CCr was also greatly improved [(37±11) ml/min before versus (51±8) ml/min at 6 months, P<0.001]. During follow-up, 61% of the patients experienced a normal renal function. Despite conventional medical treatment, systolic and diastolic blood pressures were also significantly decreased after stenting [(163±23)/(96±13) mm Hg before versus (148±12)/(79±15) mm Hg at 6 months, all P<0.001], and hypertension was well controlled in 67% of the patients at 6 months ' follow-up.Conclusion Renal artery stenting has a high success rate and is effective in improving renal function and blood pressure for patients with severe renal artery stenosis.

  4. Continuous intra-arterial blood pH monitoring in rabbits with acid-base disorders.

    Science.gov (United States)

    Jin, Weizhong; Jiang, Jinjun; Wang, Xun; Zhu, Xiaodan; Wang, Guifang; Song, Yuanlin; Bai, Chunxue

    2011-07-31

    The acid-base balance of arterial blood is important for the clinical management of seriously ill patients, especially patients with acute lung injury or acute respiratory distress syndrome. We developed a novel fluorosensor for continuous blood pH monitoring and evaluated its performance both in vitro and in vivo in rabbits with acid-base disorders. The pH sensor is made of N-allyl-4-piperazinyl-1, 8-napthalimide and 2-hydroxyethyl methacrylate, which were bonded at the distal end of the optical fiber. The fluorescence intensity increased as the pH decreased with good reproducibility, selectivity and linearity in the pH range of 6-8. The pH measurement precision was 0.03 ± 0.03 pH units with a bias of -0.02 ± 0.04 (n = 105) and -0.00 ± 0.05 pH units (n=189) in rabbits with metabolic and respiratory acid-base orders, respectively. The optical pH sensor can accurately measure pH fluctuations with a fast response and is a promising candidate for continuous in-line measurements of blood pH in critical care patients.

  5. Association of vitamin D status with arterial blood pressure and hypertension risk

    DEFF Research Database (Denmark)

    Vimaleswaran, Karani S; Cavadino, Alana; Berry, Diane J

    2014-01-01

    BACKGROUND: Low plasma 25-hydroxyvitamin D (25[OH]D) concentration is associated with high arterial blood pressure and hypertension risk, but whether this association is causal is unknown. We used a mendelian randomisation approach to test whether 25(OH)D concentration is causally associated...... with blood pressure and hypertension risk. METHODS: In this mendelian randomisation study, we generated an allele score (25[OH]D synthesis score) based on variants of genes that affect 25(OH)D synthesis or substrate availability (CYP2R1 and DHCR7), which we used as a proxy for 25(OH)D concentration. We meta......, -0·12 mm Hg, 95% CI -0·20 to -0·04; p=0·003) and reduced odds of hypertension (odds ratio [OR] 0·98, 95% CI 0·97-0·99; p=0·0003), but not with decreased diastolic blood pressure (β per 10% increase, -0·02 mm Hg, -0·08 to 0·03; p=0·37). In meta-analyses in which we combined data from D...

  6. Evaluation of tumor blood flow after feeder embolization in meningiomas by arterial spin-labeling perfusion magnetic resonance imaging.

    Science.gov (United States)

    Kawaji, Hiroshi; Koizumi, Shinichiro; Sakai, Naoto; Yamasaki, Tomohiro; Hiramatsu, Hisaya; Kanoko, Yusuke; Kamiya, Mika; Yamashita, Shuhei; Takehara, Yasuo; Sakahara, Harumi; Namba, Hiroki

    2013-10-01

    Preoperative embolization changes the amount of blood flow and pattern of flow distribution in meningioma. Tumor blood flow was investigated in eight meningioma patients before and after embolization using arterial spin-labeling (ASL) perfusion imaging. Although blood flow was significantly reduced in the whole tumor after embolization, changes in flow distribution patterns varied from one case to another. The findings suggest that evaluation of post-embolization tumor blood flow by ASL perfusion imaging would be useful in the surgical planning of meningioma.

  7. The relationship between red blood cell deformability metrics and perfusion of an artificial microvascular network.

    Science.gov (United States)

    Sosa, Jose M; Nielsen, Nathan D; Vignes, Seth M; Chen, Tanya G; Shevkoplyas, Sergey S

    2014-01-01

    The ability of red blood cells (RBC) to undergo a wide range of deformations while traversing the microvasculature is crucial for adequate perfusion. Interpretation of RBC deformability measurements performed in vitro in the context of microvascular perfusion has been notoriously difficult. This study compares the measurements of RBC deformability performed using micropore filtration and ektacytometry with the RBC ability to perfuse an artificial microvascular network (AMVN). Human RBCs were collected from healthy consenting volunteers, leukoreduced, washed and exposed to graded concentrations (0-0.08%) of glutaraldehyde (a non-specific protein cross-linker) and diamide (a spectrin-specific protein cross-linker) to impair the deformability of RBCs. Samples comprising cells with two different levels of deformability were created by adding non-deformable RBCs (hardened by exposure to 0.08% glutaraldehyde) to the sample of normal healthy RBCs. Ektacytometry indicated a nearly linear decline in RBC deformability with increasing glutaraldehyde concentration. Micropore filtration showed a significant reduction only for concentrations of glutaraldehyde higher than 0.04%. Neither micropore filtration nor ektacytometry measurements could accurately predict the AMVN perfusion. Treatment with diamide reduced RBC deformability as indicated by ektacytometry, but had no significant effect on either micropore filtration or the AMVN perfusion. Both micropore filtration and ektacytometry showed a linear decline in effective RBC deformability with increasing fraction of non-deformable RBCs in the sample. The corresponding decline in the AMVN perfusion plateaued above 50%, reflecting the innate ability of blood flow in the microvasculature to bypass occluded capillaries. Our results suggest that in vitro measurements of RBC deformability performed using either micropore filtration or ektacytometry may not represent the ability of same RBCs to perfuse microvascular networks. Further

  8. Bioprinting of artificial blood vessels: current approaches towards a demanding goal.

    Science.gov (United States)

    Hoch, Eva; Tovar, Günter E M; Borchers, Kirsten

    2014-11-01

    -linkability) functions, towards the demanding goal of biofabricating artificial blood vessels.

  9. Low-Shapiro hydrostatic reconstruction technique for blood flow simulation in large arteries with varying geometrical and mechanical properties

    Science.gov (United States)

    Ghigo, A. R.; Delestre, O.; Fullana, J.-M.; Lagrée, P.-Y.

    2017-02-01

    The purpose of this work is to construct a simple, efficient and accurate well-balanced numerical scheme for one-dimensional (1D) blood flow in large arteries with varying geometrical and mechanical properties. As the steady states at rest are not relevant for blood flow, we construct two well-balanced hydrostatic reconstruction techniques designed to preserve low-Shapiro number steady states that may occur in large network simulations. The Shapiro number Sh = u / c is the equivalent of the Froude number for shallow water equations and the Mach number for compressible Euler equations. The first is the low-Shapiro hydrostatic reconstruction (HR-LS), which is a simple and efficient method, inspired from the hydrostatic reconstruction technique (HR). The second is the subsonic hydrostatic reconstruction (HR-S), adapted here to blood flow and designed to exactly preserve all subcritical steady states. We systematically compare HR, HR-LS and HR-S in a series of single artery and arterial network numerical tests designed to evaluate their well-balanced and wave-capturing properties. The results indicate that HR is not adapted to compute blood flow in large arteries as it is unable to capture wave reflections and transmissions when large variations of the arteries' geometrical and mechanical properties are considered. On the contrary, HR-S is exactly well-balanced and is the most accurate hydrostatic reconstruction technique. However, HR-LS is able to compute low-Shapiro number steady states as well as wave reflections and transmissions with satisfying accuracy and is simpler and computationally less expensive than HR-S. We therefore recommend using HR-LS for 1D blood flow simulations in large arterial network simulations.

  10. Future Treatment of Hypertension: Shifting the Focus from Blood Pressure Lowering to Arterial Stiffness Modulation?

    Science.gov (United States)

    Fok, Henry; Cruickshank, J Kennedy

    2015-08-01

    Isolated systolic hypertension is the commonest form of hypertension from middle age onwards. Achieving target systolic blood pressure (BP) control remains difficult in everyday clinical practice and even under clinical trial conditions. Most antihypertensive medicines were designed to lower peripheral vascular resistance, which was considered the haemodynamic determinant of hypertension; most are effective in reducing steady but not pulsatile components of BP. Arterial stiffness, defined via aortic length-specific pulse wave velocity (PWV), is thought to be an important determinant of pulse pressure widening through its effects on the timing and amplitude of pressure wave reflection, and/or the aorta's Windkessel function, or its excess 'reservoir' pressure. Whereas pulse pressure is neither an independent nor consistent cardiovascular risk factor, particularly below the age of about 60 years, PWV has become the most powerful predictor of cardiovascular outcomes including mortality, independent of systolic, pulse, mean or other BP components. PWV is therefore a more direct target for treatment. This review addresses the potential therapeutic options for targeting arterial stiffness and the role of pulse pressure.

  11. Ratio of exercise and recovery systolic blood pressure integrals in prediction of coronary artery disease

    Directory of Open Access Journals (Sweden)

    Jure Mirat

    2009-02-01

    Full Text Available Aim This study was performed to determine whether the ratio (Q =A/B of area A under the curve of exercise systolic blood pressure(SBP increase and area B under curve of recovery SBP decreaseis predictive of angiographic coronary artery disease (CAD.Methods Patients who performed exercise testing and subsequentlyunderwent coronary angiography, within three months, wereanalyzed in this study. According to angiographic report, patientswere divided in three groups: without disease or with stenosis lessthan 50% (group 1, significant (group 2, and severe (group 3.Severe disease was defined as left main, three-vessel or two-vesseldisease with involvement of proximal left anterior descending artery.Results There were 137 patients included in this study (age 59 ±10, 70% male. Group 1 included 57%, group 2 included 30%,and group 3 included 13% of patients. Mean values of the Q ratiowere 2.72 ± 0.9, 1.74 ± 0.76, 1.01 ± 0.38 in groups 1, 2 and 3,respectively. By means of robust discrimination analysis, statisticallysignificant difference between groups 1, 2 and 3 in values ofthe ratio Q (p < 0.001 was found.Conclusion The ratio of exercise SBP increase and recovery SBPdecrease areas under the curve suggests severity of CAD.

  12. Real-time frequency-domain fiber optic sensor for intra-arterial blood oxygen measurements

    Science.gov (United States)

    Alcala, J. R.; Scott, Ian L.; Parker, Jennifer W.; Atwater, Beauford W.; Yu, Clement; Fischer, Russell; Bellingrath, K.

    1993-05-01

    A real time frequency domain phosphorimeter capable of measuring precise and accurate excited state lifetimes for determining oxygen is described. This frequency domain instrument does not make use of cross correlation techniques traditionally used in frequency domain fluorometers. Instead, the electrical signal from the detector is filtered to contain only the first several harmonics. This filtered signal is then sampled and averaged over a few thousand cycles. The absolute phase and absolute modulation of each sampled harmonic of the excitation and of the luminescence is computed by employing fast Fourier transform algorithms. The phase delay and the modulation ratio is then calculated at each harmonic frequency. A least squares fit is performed in the frequency domain to obtain the lifetimes of discrete exponentials. Oxygen concentrations are computed from these lifetimes. Prototypes based on these techniques were built employing commercially available components. Results from measurements in saline solution and in the arterial blood of dogs show that oxygen concentrations can be determined reproducibly. The system drift is less than 1% in over 100 hours of continuous operation. The performance of fiber optic sensors was evaluated in dogs over a period of 10 hours. The sensors tracked changes in arterial oxygen tension over the course of the experiment without instabilities. The overall response of the system was about 90 seconds. The update time was 3 seconds.

  13. A Hybrid Windkessel Model of Blood Flow in Arterial Tree Using Velocity Profile Method

    Science.gov (United States)

    Aboelkassem, Yasser; Virag, Zdravko

    2016-11-01

    For the study of pulsatile blood flow in the arterial system, we derived a coupled Windkessel-Womersley mathematical model. Initially, a 6-elements Windkessel model is proposed to describe the hemodynamics transport in terms of constant resistance, inductance and capacitance. This model can be seen as a two compartment model, in which the compartments are connected by a rigid pipe, modeled by one inductor and resistor. The first viscoelastic compartment models proximal part of the aorta, the second elastic compartment represents the rest of the arterial tree and aorta can be seen as the connection pipe. Although the proposed 6-elements lumped model was able to accurately reconstruct the aortic pressure, it can't be used to predict the axial velocity distribution in the aorta and the wall shear stress and consequently, proper time varying pressure drop. We then modified this lumped model by replacing the connection pipe circuit elements with a vessel having a radius R and a length L. The pulsatile flow motions in the vessel are resolved instantaneously along with the Windkessel like model enable not only accurate prediction of the aortic pressure but also wall shear stress and frictional pressure drop. The proposed hybrid model has been validated using several in-vivo aortic pressure and flow rate data acquired from different species such as, humans, dogs and pigs. The method accurately predicts the time variation of wall shear stress and frictional pressure drop. Institute for Computational Medicine, Dept. Biomedical Engineering.

  14. Arterial pressure and cerebral blood flow variability: friend or foe? A review

    Directory of Open Access Journals (Sweden)

    Caroline Alice Rickards

    2014-04-01

    Full Text Available Variability in arterial pressure and cerebral blood flow has traditionally been interpreted as a marker of cardiovascular decompensation, and has been associated with negative clinical outcomes across varying time scales, from impending orthostatic syncope to an increased risk of stroke. Emerging evidence, however, suggests that increased hemodynamic variability may, in fact, be protective in the face of acute challenges to perfusion, including significant central hypovolemia and hypotension (including hemorrhage, and during cardiac bypass surgery. This review presents the dichotomous views on the role of hemodynamic variability on clinical outcome, including the physiological mechanisms underlying these patterns, and the potential impact of increased and decreased variability on cerebral perfusion and oxygenation. We suggest that reconciliation of these two apparently discrepant views may lie in the time scale of hemodynamic variability; short time scale variability appears to be cerebroprotective, while mid to longer term fluctuations are associated with primary and secondary end-organ dysfunction.

  15. Loss of alveolar membrane diffusing capacity and pulmonary capillary blood volume in pulmonary arterial hypertension

    Science.gov (United States)

    2013-01-01

    Background Reduced gas transfer in patients with pulmonary arterial hypertension (PAH) is traditionally attributed to remodeling and progressive loss of pulmonary arterial vasculature that results in decreased capillary blood volume available for gas exchange. Methods We tested this hypothesis by determination of lung diffusing capacity (DL) and its components, the alveolar capillary membrane diffusing capacity (Dm) and lung capillary blood volume (Vc) in 28 individuals with PAH in comparison to 41 healthy individuals, and in 19 PAH patients over time. Using single breath simultaneous measure of diffusion of carbon monoxide (DLCO) and nitric oxide (DLNO), DL and Dm were respectively determined, and Vc calculated. Dm and Vc were evaluated over time in relation to standard clinical indicators of disease severity, including brain natriuretic peptide (BNP), 6-minute walk distance (6MWD) and right ventricular systolic pressure (RVSP) by echocardiography. Results Both DLCO and DLNO were reduced in PAH as compared to controls and the lower DL in PAH was due to loss of both Dm and Vc (all p DLNO decreased by 24 ml/min/mmHg/year (p = 0.01). Consequently, Dm decreased and Vc tended to increase over time, which led to deterioration of the Dm/Vc ratio, a measure of alveolar-capillary membrane functional efficiency without changes in clinical markers. Conclusions The findings indicate that lower than normal gas transfer in PAH is due to loss of both Dm and Vc, but that deterioration of Dm/Vc over time is related to worsening membrane diffusion. PMID:23339456

  16. Long-term effects on the histology and function of livers and spleens in rats after 33% toploading of PEG-PLA-nano artificial red blood cells.

    Science.gov (United States)

    Liu, Zun Chang; Chang, Thomas M S

    2008-01-01

    This study is to investigate the long-term effects of nanodimension PEG-PLA artificial red blood cells containing hemoglobin and red blood cell enzymes on the liver and spleen after 1/3 blood volume top loading in rats. The experimental rats received one of the following infusions: Nano artificial red blood cells in Ringer lactate, Ringer lactate, stroma-free hemoglobin, polyhemoglobin, and autologous rat whole blood. Blood samples were taken before infusions and on days 1, 7, and 21 after infusions for analysis. Nano artificial red blood cells, polyhemoglobin, Ringer lactate and rat red blood cells did not have any significant adverse effects on alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, creatine kinase, amylase and creatine kinase. On the other hand, stroma-free hemoglobin induced significant adverse effects on liver as shown by elevation in alanine aminotransferase and aspartate aminotransferase throughout the 21 days. On day 21 after infusions rats were sacrificed and livers and spleens were excised for histological examination. Nano artificial red blood cells, polyhemoglobin, Ringer lactate and rat red blood cells did not cause any abnormalities in the microscopic histology of the livers and spleens. In the stroma-free hemoglobin group the livers showed accumulation of hemoglobin in central veins and sinusoids, and hepatic steatosis. In conclusion, injected nano artificial red blood cells can be efficiently metabolized and removed by the reticuloendothelial system, and do not have any biochemical or histological adverse effects on the livers or the spleens.

  17. Anatomical vertebral artery hypoplasia and insufficiency impairs dynamic blood flow regulation.

    Science.gov (United States)

    Sato, Kohei; Yoneya, Marina; Otsuki, Aki; Sadamoto, Tomoko; Ogoh, Shigehiko

    2015-11-01

    Recent studies have suggested that vertebral artery (VA) hypoplasia is a predisposing factor for posterior cerebral stroke. We examined whether anatomical vertebrobasilar ischemia, i.e., unilateral VA hypoplasia and insufficiency, impairs dynamic blood flow regulation. Twenty-eight female subjects were divided into three groups by defined criteria: (i) unilateral VA hypoplasia (n = 8), (ii) VA insufficiency (n = 6), and (iii) control (n = 14). Hypoplastic VA criterion was VA blood flow of 40 ml min(-1) , whereas VA insufficiency criterion was net (left + right) VA blood flow of 100 ml min(-1) or less. We evaluated left, right, and net VA blood flows by ultrasonography during hypercapnia, normocapnia, and hypocapnia to evaluate VA CO2 reactivity. The unilateral VA hypoplasia group showed lower CO2 reactivity at hypoplastic VA than at non-hypoplastic VA (2.65 ± 0.58 versus 3.00 ± 0.48% per mmHg, P = 0.027) and net VA CO2 reactivity was preserved (Unilateral VA hypoplasia, 2.95 ± 0.48 versus Control, 2.93 ± 0.42% per mmHg, P = 0.992). However, the VA insufficiency group showed a lower net VA CO2 reactivity compared to the control (2.29 ± 0.55 versus 2.93 ± 0.42% per mmHg, P = 0.032) and the unilateral VA hypoplasia (P = 0.046). VA hypoplasia reduced CO2 reactivity, although non-hypoplastic VA may compensate this regulatory limitation. In subjects with VA insufficiency, lowered CO2 reactivity at the both VA could not preserve normal net VA CO2 reactivity. These findings provide a possible physiological mechanism for the increased risk of posterior cerebral stroke in subjects with VA hypoplasia and insufficiency.

  18. PHARMACOLOGICAL CORRECTION OF CEREBRAL BLOOD FLOW DISTURBANCES IN WOMEN WITH ARTERIAL HYPERTENSION IN POSTMENOPAUSE

    Directory of Open Access Journals (Sweden)

    V. V. Yakusevich

    2005-01-01

    Full Text Available Aim: to study cerebral blood flow and cholesterol metabolism in menopausal women with arterial hypertension (AH; to evaluate dynamics of cerebral blood flow parameters and plasma lipid concentrations in these patients during 6-month antihypertensive and hypolipidemic therapy.Material and methods: 24 women with AH of I and II grade were examined. They were in postmenopausal period of life during 7,1±0,5 years. At the beginning of the study all women were prescribed moexipril as monotherapy, daily dose 7,5 – 15 mg. Patients with initial dislipidemia were prescribed lipid reducing drug atorvastatin in 10mg daily dose additionally to the antihypertensive therapy. Therefore all the patients were divided into two groups: I – monoteraphy with moexipril (13 people, II – combined therapy with moexipril and atorvastatin (11 people. At the beginning of the study and after 6 months all the patients passed through ultrasonic Dopplerography of vessels of head and neck, rheoencephalography, their lipoproteidogrammes were studied.Results: During 6-month therapy all the patients showed proved decrease in systolic and diastolic blood pressure, also positive dynamics of neuropsychological status, improvement in cerebral blood flow according to the results of Dopplerography of vessels and rheoencephalography. Normalization of plasma lipid spectrum was noted. More significant positive changes in cerebral hemodynamic parameters and plasma lipid spectrum were observed in patients, who received combined therapy with antihypertensive and lipid reducing drugs.Conclusion: Deterioration of cerebral hemodynamics is typical for women with long-lasting AH. The most positive influence on cerebral perfusion was received due to combined therapy with moexipril and atorvastatin.

  19. Novel Approach to Repeated Arterial Blood Sampling in Small Animal PET : Application in a Test-Retest Study with the Adenosine A1 Receptor Ligand [C-11]MPDX

    NARCIS (Netherlands)

    Sijbesma, Jürgen W A; Zhou, Xiaoyun; Vállez García, David; Houwertjes, Martin C; Doorduin, Janine; Kwizera, Chantal; Maas, Bram; Meerlo, Peter; Dierckx, Rudi A; Slart, Riemer H J A; Elsinga, Philip H; van Waarde, Aren

    2016-01-01

    Small animal positron emission tomography (PET) can be used to detect small changes in neuroreceptor availability. This often requires rapid arterial blood sampling. However, current catheterization procedures do not allow repeated blood sampling. We have developed a procedure which allows arterial

  20. Roles of preoperative arterial blood gas tests in the surgical treatment of scoliosis with moderate or severe pulmonary dysfunction

    Institute of Scientific and Technical Information of China (English)

    LIU Jia-ming; SHEN Jian-xiong; ZHANG Jian-guo; ZHAO Hong; LI Shu-gang; ZHAO Yu; QIU Giu-xing

    2012-01-01

    Background It has been stated that preoperative pulmonary function tests are essential to assess the surgical risk in patients with scoliosis.Arterial blood gas tests have also been used to evaluate pulmonary function before scoliotic surgery.However,few studies have been reported.The aim of this study was to investigate the roles of preoperative arterial blood gas tests in the surgical treatment of scoliosis with moderate or severe pulmonary dysfunction.Methods This study involved scoliotic patients with moderate or severe pulmonary dysfunction (forced vital capacity <60%) who underwent surgical treatment between January 2002 and April 2010.A total of 73 scoliotic patients (23 males and 50 females) with moderate or severe pulmonary dysfunction were included.The average age of the patients was 16.53 years (ranged 10-44).The demographic distribution,medical records,and radiographs of all patients were collected.All patients received arterial blood gas tests and pulmonary function tests before surgery.The arterial blood gas tests included five parameters:partial pressure of arterial oxygen,partial pressure of arterial carbon dioxide,alveolar-arterial oxygen tension gradient,pH,and standard bases excess.The pulmonary function tests included three parameters:forced expiratory volume in 1 second ratio,forced vital capacity ratio,and peak expiratory flow ratio.All five parameters of the arterial blood gas tests were compared between the two groups with or without postoperative pulmonary complications by variance analysis.Similarly,all three parameters of the pulmonary function tests were compared.Results The average coronal Cobb angle before surgery was 97.42° (range,50°-180°).A total of 15 (20.5%) patients had postoperative pulmonary complications,including hypoxemia in 5 cases (33.3%),increased requirement for postoperative ventilatory support in 4 (26.7%),pneumonia in 2 (13.3%),atelectasis in 2 (13.3%),pneumothorax in 1 (6.7%),and hydrothorax in 1

  1. Closure of digital arteries in high vascular tone states as demonstrated by measurement of systolic blood pressure in the fingers

    DEFF Research Database (Denmark)

    Krähenbühl, B; Nielsen, S L; Lassen, N A

    1977-01-01

    Finger systolic blood pressure (FSP) was measured indirectly in normal subjects and patients with primary Raynaud phenomenon by applying a thin-walled plastic cuff around the finger and a strain gauge more distally to detect volume changes. Inducing a high vascular tone in one or more fingers...... by direct cooling or intra-arterial noradrenaline infusion caused a marked drop in FSP in the exposed fingers, but not in the non-exposed fingers of the same hand. The fact that the non-exposed fingers retained the normal (arm systolic) pressure level is taken to indicate that palmar arch blood pressure...... also remained normal. In the high vascular tone state, a large transmural pressure difference must apparently be established before the digital arteries are forced open. The lowered opening pressure constitutes a manifestation of the closure phenomenon of the digital arteries described in patients...

  2. Duplex Color Doppler Evaluation of Retinal Arterial Blood Flow in Type 2 Diabetic Subjects without Retinopathy

    Directory of Open Access Journals (Sweden)

    Mashah Binte Amin

    2014-09-01

    Full Text Available Background: Diabetic retinopathy is a vascular disorder affecting the microvasculature of retina. It is caused by changes in the blood vessels of retina. If untreated, it may lead to blindness which is usually preventable if retinopathy is diagnosed early and treated promptly. In ophthalmology, color Doppler imaging is a new method that enables us to assess the orbital vasculature. It allows for simultaneous two dimensional anatomical and Doppler evaluations of hemodynamic characteristics of retinal artery. Objective: To observe the difference between Doppler flow velocity indices (peak systolic velocity, end diastolic velocity and resistive index of retinal artery in type 2 diabetic subjects without retinopathy and those of normal controls. Materials and Methods: This case-control study was carried out in the department of Radiology and Imaging, Bangladesh Institute of Research and Rehabilitation in Diabetes, Endocrine and Metabolic Disorders (BIRDEM in collaboration with Ophthalmology Outpatient Department, BIRDEM, Dhaka from July 2011 to June 2013. Eighty diabetic patients without retinopathy aged 27–68 years were enrolled as cases and age and sex matched 80 healthy subjects were selected as controls. Type 1 diabetic patients, type 2 diabetics with retinopathy, hypertensive and dyslipidemic subjects were excluded from the study. All the selected subjects underwent duplex Doppler ultrasonography of both eyes using 5 to 7.5 MHZ linear phase transducer. Duplex color Doppler findings including spectral analysis (PSV, EDV and RI were recorded. Unpaired t test was done to compare blood flow velocity indices of retinal artery in type 2 diabetic patients without retinopathy and that of healthy control subjects. p value <0.05 was considered as significant. Results: Majority (42.5% and 47.5% of subjects were in 4th decade of life in both groups with predominance of males. The mean duration of diabetes was 4.56 ± 2.1 years. Mean peak systolic

  3. Effect of artificial colloids on blood coagulation during shock stage of severe burn injury

    Institute of Scientific and Technical Information of China (English)

    ZHOU Jian-jun; XING Nan; CHEN Jiong; SHI Jian-wu; SU Guo-liang

    2013-01-01

    Background There are controversies about the use of artificial colloids.This research was aimed to determine the effect of various artificial colloids on blood coagulation in the shock stage of severe burn injury.Methods Totally,18 female Ba-Ma mini-pigs were subjected to a 40% total body surface third-degree flame burn under anesthesia.Resuscitation therapy was applied 2 hours after the injury,using the burn shock fluid resuscitation formula commonly accepted in the surgical treatment of burns.The Ba-Ma mini-pigs were randomly assigned to three groups (six pigs in each group):succinylated gelatin group (the artificial colloid used was succinylated gelatin Injection),hydroxyethyl starch group (the artificial colloid used was hydroxyethyl starch (130/0.4)),and allogeneic plasma group (the colloid used was allogeneic plasma).Blood samples were collected from the animals prior to the burn injury and again at intervals of 4,8,24 and 48 hours post-injury.The platelet count (PLT),prothrombin time (PT),international normalized ratio (INR),activated partial thromboplastin time (APTT),and fibrinogen (Fib) were measured,followed by a statistical analysis of all results.Results The PLT of succinylated gelatin group and hydroxyethyl starch group at intervals of 24 and 48 hours were (124.3±52.7),(78.8±16.4)×109/L and (159.0±62.8),(87.3±32.0)×109/L respectively.But in the allogeneic plasma group at intervals of 8,24,and 48 hours were (234.3±52.6),(136.0±47.4),(75.8±31.0)×109/L.The decrease were all statistically significant (P <0.05,P <0.01) when compared to pre-burn ((383.3±77.9),(382.7±65.7),(381.0±49.4)×109/L).The PLT among the three groups,at all the time points,had no statistical difference (P >0.05).Compared to pre-burn ((10.8±0.9),(11.4±0.8),(10.6±0.7) seconds),the PT of succinylated gelatin group and hydroxyethyl starch group at 24 hours were (14.5±1.5) and (16.2±1.3) seconds,whereas in the allogeneic plasma group at 8 and 24 hours the PT were

  4. Pressão arterial entre trabalhadores de curtume Blood pressure among tannery workers

    Directory of Open Access Journals (Sweden)

    Ricardo Cordeiro

    1998-10-01

    Full Text Available INTRODUÇÃO: O grupo das doenças cardiovasculares tem sido apontado como a principal causa de óbito no Brasil desde os anos 70, sendo a hipertensão arterial sistêmica (HAS o fator de risco mais importante para esse grupo. Entre os trabalhadores observa-se correlação negativa entre o status ocupacional e a pressão arterial. Tais fatos ressaltam a importância do conhecimento da distribuição da pressão arterial sistêmica entre os distintos grupos profissionais. Assim, foi realizado estudo para descrever o status pressórico de uma população homogênea e estável de trabalhadores do setor secundário da economia, pouco especializados e que ganham baixos salários, estabelecendo a prevalência da HAS nesse grupo específico, relacionando-a com algumas covariáveis biológicas e socioeconômicas, e comparando-a com a prevalência de HAS em outros grupos profissionais no Brasil. MÉTODO: Foram estudados 73 trabalhadores regularmente empregados em julho de 1993 em um curtume situado no Município de Botucatu, cidade de médio porte da região Centro-Oeste do Estado de São Paulo, os quais foram submetidos a exame antropométrico, aferição de pressão arterial, anamnese e exame clínico. Os resultados foram comparados com os obtidos em estudos semelhantes, controlando-se o confundimento da idade por intermédio de diferentes técnicas. RESULTADOS: A prevalência bruta da HAS encontrada foi de 56,1%, sendo 15,8% a prevalência de hipertensão sistólica isolada. Ambas se associaram ao etilismo e ao tabagismo na população estudada. DISCUSSÃO: A prevalência da hipertensão foi consideravelmente alta e significativamente maior do que a encontrada em outros grupos de trabalhadores estudados no Brasil. Tal achado ressalta a necessidade da continuidade da investigação, objetivando o isolamento dos fatores implicados na elevação pressórica do grupo estudado.INTRODUCTION: Cardiovascular diseases have been shown to be the leading cause of

  5. The relationship between exercise-induced muscle fatigue, arterial blood flow and muscle perfusion after 56 days local muscle unloading.

    Science.gov (United States)

    Weber, Tobias; Ducos, Michel; Mulder, Edwin; Beijer, Åsa; Herrera, Frankyn; Zange, Jochen; Degens, Hans; Bloch, Wilhelm; Rittweger, Jörn

    2014-05-01

    In the light of the dynamic nature of habitual plantar flexor activity, we utilized an incremental isokinetic exercise test (IIET) to assess the work-related power deficit (WoRPD) as a measure for exercise-induced muscle fatigue before and after prolonged calf muscle unloading and in relation to arterial blood flow and muscle perfusion. Eleven male subjects (31 ± 6 years) wore the HEPHAISTOS unloading orthosis unilaterally for 56 days. It allows habitual ambulation while greatly reducing plantar flexor activity and torque production. Endpoint measurements encompassed arterial blood flow, measured in the femoral artery using Doppler ultrasound, oxygenation of the soleus muscle assessed by near-infrared spectroscopy, lactate concentrations determined in capillary blood and muscle activity using soleus muscle surface electromyography. Furthermore, soleus muscle biopsies were taken to investigate morphological muscle changes. After the intervention, maximal isokinetic torque was reduced by 23·4 ± 8·2% (PBlood flow, tissue oxygenation, lactate concentrations and EMG median frequency kinematics during the exercise test were comparable before and after the intervention, whereas the increase of RMS in response to IIET was less following the intervention (P = 0·03). In conclusion, following submaximal isokinetic muscle work exercise-induced muscle fatigue is unaffected after prolonged local muscle unloading. The observation that arterial blood flow was maintained may underlie the unchanged fatigability.

  6. Absolute Versus Relative Myocardial Blood Flow by Dynamic CT Myocardial Perfusion Imaging in Patients With Anatomic Coronary Artery Disease

    NARCIS (Netherlands)

    Wichmann, Julian L.; Meinel, Felix G.; Schoepf, U. Joseph; Lo, Gladys G.; Choe, Yeon Hyeon; Wang, Yining; Vliegenthart, Rozemarijn; Varga-Szemes, Akos; Muscogiuri, Giuseppe; Cannao, Paola M.; De Cecco, Carlo N.

    2015-01-01

    OBJECTIVE. The purpose of this study was to evaluate differences in the diagnostic accuracy of absolute and relative territorial myocardial blood flow (MBF) derived from stress dynamic CT myocardial perfusion imaging (MPI) for the detection of significant coronary artery stenosis. MATERIALS AND METH

  7. Effects of sodium and potassium supplementation on blood pressure and arterial stiffness : a fully controlled dietary intervention study

    NARCIS (Netherlands)

    Gijsbers, L.; Dower, J. I.; Mensink, M.; Siebelink, E.; Bakker, S. J. L.; Geleijnse, J. M.

    2015-01-01

    We performed a randomised, placebo-controlled, crossover study to examine the effects of sodium and potassium supplementation on blood pressure (BP) and arterial stiffness in untreated (pre) hypertensive individuals. During the study, subjects were on a fully controlled diet that was relatively low

  8. Open and Closed Endotracheal Suctioning and Arterial Blood Gas Values: A Single-Blind Crossover Randomized Clinical Trial

    Directory of Open Access Journals (Sweden)

    Azam Faraji

    2015-01-01

    Full Text Available Aim. This study was aimed at comparing the effects of the open and closed suctioning techniques on the arterial blood gas values in patients undergoing open-heart surgery. Methods. In a clinical trial, we recruited 42 patients after open-heart surgery in an educational hospital. Each patient randomly underwent both open and closed suctioning. ABGs, PaO2, SaO2, PaCO2, were analyzed before and one, five, and fifteen minutes after each suctioning episode. Results. At first the pressure of oxygen in arterial blood increased; however, this increase in the open technique was greater than that of the closed system (P<0.001. The pressure of oxygen decreased five and fifteen minutes after both suctioning techniques (P<0.05. The trends of carbon dioxide variations after the open and closed techniques were upward and downward, respectively. Moreover, the decrease in the level of oxygen saturation five and fifteen minutes after the open suctioning was greater than that of the closed suctioning technique (P<0.05.  Conclusion. Arterial blood gas disturbances in the closed suctioning technique were less than those of the open technique. Therefore, to eliminate the unwanted effects of endotracheal suctioning on the arterial blood gases, the closed suctioning technique is recommended.

  9. MRA Images Identification of the Artery Blood Vessel of the Knee with SOM LVQ Neural Networks as Auxiliary.

    Science.gov (United States)

    Huang, Hung-Chun; Chien, Chia-Hung; Shih, Ting-Fang; Chong, Fok-Ching

    2005-01-01

    The ways of angiography are divided into two kinds at present: the invasive type and the non invasive type. Because the magnetic resonance angiography (MRA) has advantages of the non invasive type, thus people can accept MRA more easily. Presently, to diagnoses for the initial stage triage of the blood vessel on clinic by MRA mostly. We to be allowed to see clearly that the shape of lower limb artery which like the dendrite and the blood vessel is thick from the trunk to the thin branch, also we can see the narrow embolism and the blocked place through MRA. This study is aiming at the image of artery of blood vessel by MRA assay, and is attempting to use two-dimensional structure of SOM and LVQ to make out topologies for the shape of artery of blood vessel. We expect that MRA could be useful tools for earlier on the quick triage and auxiliary diagnosis of doctors. By actual examples truly prove that patients after peripheral arterial occlusive disease (PAOD) treatment can diagnose effectively, shorten the time of patients waiting for reports and improve the whole efficiency of the medical treatment system.

  10. An artificial pancreas for automated blood glucose control in patients with Type 1 diabetes.

    Science.gov (United States)

    Schmidt, Signe; Boiroux, Dimitri; Ranjan, Ajenthen; Jørgensen, John Bagterp; Madsen, Henrik; Nørgaard, Kirsten

    2015-01-01

    Automated glucose control in patients with Type 1 diabetes is much-coveted by patients, relatives and healthcare professionals. It is the expectation that a system for automated control, also know as an artificial pancreas, will improve glucose control, reduce the risk of diabetes complications and markedly improve patient quality of life. An artificial pancreas consists of portable devices for glucose sensing and insulin delivery which are controlled by an algorithm residing on a computer. The technology is still under development and currently no artificial pancreas is commercially available. This review gives an introduction to recent progress, challenges and future prospects within the field of artificial pancreas research.

  11. Aging in blood vessels. Medicinal agents FOR systemic arterial hypertension in the elderly.

    Science.gov (United States)

    Rubio-Ruiz, María Esther; Pérez-Torres, Israel; Soto, María Elena; Pastelín, Gustavo; Guarner-Lans, Verónica

    2014-11-01

    Aging impairs blood vessel function and leads to cardiovascular disease. The mechanisms underlying the age-related endothelial, smooth muscle and extracellular matrix vascular dysfunction are discussed. Vascular dysfunction is caused by: (1) Oxidative stress enhancement. (2) Reduction of nitric oxide (NO) bioavailability, by diminished NO synthesis and/or augmented NO scavenging. (3) Production of vasoconstrictor/vasodilator factor imbalances. (4) Low-grade pro-inflammatory environment. (5) Impaired angiogenesis. (6) Endothelial cell senescence. The aging process in vascular smooth muscle is characterized by: (1) Altered replicating potential. (2) Change in cellular phenotype. (3) Changes in responsiveness to contracting and relaxing mediators. (4) Changes in intracellular signaling functions. Systemic arterial hypertension is an age-dependent disorder, and almost half of the elderly human population is hypertensive. The influence of hypertension on the aging cardiovascular system has been studied in models of hypertensive rats. Treatment for hypertension is recommended in the elderly. Lifestyle modifications, natural compounds and hormone therapies are useful for initial stages and as supporting treatment with medication but evidence from clinical trials in this population is needed. Since all antihypertensive agents can lower blood pressure in the elderly, therapy should be based on its potential side effects and drug interactions.

  12. Activity of the positive and negative reinforcement motivation systems and baseline arterial blood pressure in humans.

    Science.gov (United States)

    Aftanas, L I; Sidorova, P V; Pavlov, S V; Makhnev, V P; Korenek, V V; Reva, N V; Amstislavskaya, T G

    2008-10-01

    The aim of the present work was to identify possible associations between individual balances in the activity of the positive and negative reinforcement motivation systems using a method based on emotional modulation of the startle reaction (EMSR) by motivationally significant emotionally positive and negative contextual visual stimuli and measures of cardiovascular system activity. Studies were performed using healthy males (mean age 30.29 +/- 9.8 years) with normal and first-episode excessive increases in arterial blood pressure (systolic blood pressure to greater than 140 mmHg, diastolic to greater than 90 mmHg). Cluster analysis of EMSR data identified groups of individuals with different activity profiles for the positive and negative reinforcement systems. Groups of subjects with changes in the balance of activity towards a lower level of positive reinforcement system activity (smaller startle reflexes to positive contextual stimuli) or a higher level of negative reinforcement system activity (larger startle reactions to threatening contextual stimuli) showed significantly greater baseline SBP and DBP. The possible mechanisms of the modulatory influences of the balance of system activities on autonomic vascular regulatory processes are discussed.

  13. Sleep Bruxism Is Associated with a Rise in Arterial Blood Pressure

    Science.gov (United States)

    Nashed, Angela; Lanfranchi, Paola; Rompré, Pierre; Carra, Maria Clotilde; Mayer, Pierre; Colombo, Roberto; Huynh, Nelly; Lavigne, Gilles

    2012-01-01

    Study Objectives: Sleep bruxism (SB) is a movement disorder identified by grinding of teeth and rhythmic masticatory muscle activity (RMMA). RMMA is associated with body movements and cortical arousals. Increases in autonomic sympathetic activities that characterize sleep cortical arousal precede RMMA/SB. Based on these findings, this study examined whether RMMA/SB episodes are also associated with significant changes in arterial blood pressure (BP). Design: Participants underwent 3 nights of full polysomnography that included noninvasive beat-to-beat BP recording. Single RMMA/SB episodes and arousal episodes were analyzed in stage 2 sleep and categorized as: (i) RMMA/SB + arousal; (ii) RMMA/SB + body movement; (iii) RMMA/SB + arousal + body movement; or (iv) arousal alone. Sleep and RMMA/SB data were compared to a Non SB group. RMMA/SB clusters (RMMA/SB episodes ≤ 30 sec apart) were also analyzed. Setting: Sleep Laboratory at l'Hôpital du Sacré-Coeur de Montréal. Participants: Ten young, healthy participants with SB (mean age = 26 ± 1.8 years) and 9 without SB (mean age = 29 ± 1.2 years). Interventions: N/A Measurements and Results: BP increased with all RMMA/SB and arousal episodes (P ≤ 0.05). The average maximum BP surges (systolic/diastolic ± SE mm Hg) were: 25.6 ± 3.3/12.6 ± 2.0 for RMMA/SB + arousal; 30.1 ± 1.7/19.1 ± 1.9 for RMMA/SB + body movement; 26.0 ± 2.8/15.1 ± 2.0 for RMMA/SB + arousal + body movement; 19.4 ± 2.3/8.9 ± 1.2 for arousal alone; and for RMMA/SB clusters: Episode: 1: 26.2 ± 8.7/16.4 ± 5.7; Episode 2: 21.1 ± 7.9/12.6 ± 6.4. Conclusion: Rhythmic masticatory muscle activity/sleep bruxism (RMMA/SB) is associated with blood pressure fluctuations during sleep. Arousals and body movements often occur with RMMA/SB and can impact the magnitude of this BP surge. Citation: Nashed A; Lanfranchi P; Rompré P; Carra MC; Mayer P; Colombo R; Huynh N; Lavigne G. Sleep bruxism is associated with a rise in arterial blood pressure. SLEEP

  14. Changes of Arterial Blood Gases After Different Ranges of Surgical Lung Resection

    Science.gov (United States)

    Cukic, Vesna; Lovre, Vladimir

    2012-01-01

    Introduction: In recent years there has been increase in the number of patients who need thoracic surgery – first of all different types of pulmonary resection because of primary bronchial cancer, and very often among patients whose lung function is impaired due to different degree of bronchial obstruction so it is necessary to assess functional status before and after lung surgery to avoid the development of respiratory insufficiency. Objective: To show the changes in the level of arterial blood gases after various ranges of lung resection. Material and methods: The study was done on 71 patients surgically treated at the Clinic for Thoracic Surgery KCU Sarajevo, who were previously treated at the Clinic for Pulmonary Diseases “Podhrastovi” in the period from 01. 06. 2009. to 01. 09. 2011. Different types of lung resection were made. Patients whose percentage of ppoFEV1 was (prognosed postoperative FEV1) was less than 30% of normal values of FEV1 for that patients were not given a permission for lung resection. We monitored the changes in levels-partial pressures of blood gases (PaO2, PaCO2 and SaO2) one and two months after resection and compared them to preoperative values. As there were no significant differences between the values obtained one and two months after surgery, in the results we showed arterial blood gas analysis obtained two months after surgical resection. Results were statistically analyzed by SPSS and Microsoft Office Excel. Statistical significance was determined at an interval of 95%. Results: In 59 patients (83%) there was an increase, and in 12 patients (17%) there was a decrease of PaO2, compared to preoperative values. In 58 patients (82%) there was a decrease, and in 13 patients (18%) there was an increase in PaCO2, compared to preoperative values. For all subjects (group as whole): The value of the PaO2 was significantly increased after lung surgery compared to preoperative values (p <0.05) so is the value of the SaO2%. The value

  15. A pressão arterial está sendo medida? Is the blood pressure being measured?

    Directory of Open Access Journals (Sweden)

    Débora C. Alavarce

    2000-03-01

    Full Text Available A medida da pressão arterial faz parte do exame físico e deve ser realizada em toda consulta médica. Para avaliar se a pressão arterial é medida nas consultas médicas, foram consultados 500 prontuários de pacientes de primeira consulta ambulatorial, sendo 335 (67% provenientes de clínicas médicas e cirúrgicas e 165 (33% das clínicas ginecológica e obstétrica. A pressão arterial foi anotada em 39% das consultas realizadas (135±32/85±19 mm Hg, sendo que em 11% destas anotações a pressão diastólica estava acima de 90 mm Hg. Em relação ao diagnóstico prévio de hipertensão arterial verificou-se que: a em 62% dos prontuários não havia esta informação; b 20% referiram ter hipertensão, e em 79% destes a pressão arterial foi anotada; e c 18% referiram não ter hipertensão e 46% destes tiveram registro da pressão arterial. Portanto, a maior parte dos pacientes não teve sua pressão arterial anotada.The blood pressure measure is part of the physical exam and it should be accomplished in every medical consultation. To verify the blood pressure measured in the accomplished medical consultations record of first they were consulted it consults 500 patient's ambulatorial being 335 (67% coming of medical and surgical clinics and 165 (33% of the gynecological and obstetric clinics. The blood pressure was written down in 39% of the accomplished consultations (135+32 mm Hg 85+19 mm Hg, and 11% of this annotations the pressure diastólica was above 90 mm Hg. In relation to the previous diagnosis of hypertension it was verified that: a in 62% of the records there was not this information; b 20% referred to have hypertension, and in 79% of these the arterial pressure was scored; and c 18% referred not to have hypertension and 46% of these had registration of the arterial pressure. Therefore, most of the patients didn't have its logged arterial pressure.

  16. The arterial blood supply of the temporomandibular joint: an anatomical study and clinical implications

    Energy Technology Data Exchange (ETDEWEB)

    Cuccia, Antonino Marco; Caradonna, Carola; Caradonna, Domenico [Dept. of Surgical and Oncological Disciplines, University of Palermo, Palermo (Italy); Anastasi, Giuseppe; Milardi, Demetrio; Favaloro, Angelo; Caradonna, Luigi; Cutroneo, Giuseppina [Biomorphology and Biotechnologies, University of Messina, Messina (Italy); De Pietro, Anita; Angileri, Tommaso Maurizio [Villa Santa Teresa, Diagnostica per Immagini, Palermo (Italy)

    2013-03-15

    The aim of this study was to analyze three-dimensional images of the arterial supply to the temporomandibular joint. Ten patients (five men and five women, mean age 36 years) without signs or symptoms of temporomandibular disorders, who underwent contrast-enhanced computed tomographic (CT) scanning with intravenous contrast, were studied. The direct volume rendering technique of CT images was used, and a data set of images to visualize the vasculature of the human temporomandibular joint in three dimensions was created. After elaboration of the data through post-processing, the arterial supply of the temporomandibular joint was studied. The analysis revealed the superficial temporal artery, the anterior tympanic artery, the deep temporal artery, the auricular posterior artery, the transverse facial artery, the middle meningeal artery, and the maxillary artery with their branches as the main arterial sources for the lateral and medial temporomandibular joint. The direct volume rendering technique was found to be successful in the assessment of the arterial supply to the temporomandibular joint. The superficial temporal artery and maxillary artery ran along the lateral and medial sides of the condylar neck, suggesting that these arteries are at increased risk during soft-tissue procedures such as an elective arthroplasty of the temporomandibular joint.

  17. Imaging of Blood Flow in Cerebral Arteries with Dynamic Helical Computed Tomography Angiography (DHCTA) Using a 64-Row CT Scanner

    Energy Technology Data Exchange (ETDEWEB)

    Pekkola, J.; Kangasniemi, M. (Helsinki Medical Imaging Center, Helsinki Univ. Central Hospital, Helsinki (Finland))

    2009-08-15

    Background: Cerebral computed tomography angiography (CTA) depicts a structural image of intracranial arteries without providing much time-resolved information on blood flow dynamics. Current CT technology allows obtaining of rapidly repeated helical scans during the arterial contrast filling phase after an intravenous contrast injection. Purpose: To report our experience on dynamic CT imaging in determining the direction of contrast filling within proximal intracranial arteries of operated cerebral artery aneurysm patients. Such dynamic information can help detect vascular occlusion or severe spasm. The method is here referred to as dynamic helical CT angiography (DHCTA). Material and Methods: We retrospectively collected image and related technical data for 23 patients who underwent DHCTA and CTA during their first postoperative day after cerebral artery aneurysm surgery. For DHCTA, we had helically scanned a 4-cm tissue volume three times in succession with a 64-row CT scanner at intervals of 2.6 s during arterial contrast filling after an intravenous contrast injection. We assessed how well DHCTA succeeded in demonstrating the direction of contrast filling in the proximal intracranial arteries, evaluated clinically relevant structural information provided by DHCTA and CTA, and compared radiation doses for the two methods. Results: For 21 patients, DHCTA outlined the direction of contrast filling in proximal intracranial arteries. As to arterial spasm and residual filling of the operated aneurysm, CTA and DHCTA gave similar information. Radiation doses were higher (P<0.000001) for DHCTA than for CTA at 120 kV tube voltage. At 100 kV, the difference was smaller, but doses for DHCTA still exceeded (P<0.05) those for CTA. Conclusion: DHCTA gave dynamic information unobtainable with CTA and could prove useful in selected clinical settings

  18. [The influence of cardiosurgical intervention type and conditions of artificial blood circulation of perioperative dynamics of cardiac biomarkers].

    Science.gov (United States)

    Dement'eva, I I; Morozov, Iu A; Charnaia, M A

    2013-01-01

    125 patients after cardiac surgery operated on with the use of artificial blood circulation (ABC) were followed-up. Blood levels of cardiac protein, binding aliphatic acids and troponin 1 and 3 days after the operation were registered. The study showed that aorta clamping more then 90 minutes and hypothermic perfusion regimen influence cardiomyocites negatively. The state of "surgical trauma" and reperfusional myocardium damage was approximately the same during aortic surgery, myocardium revascularization with the use of aortic clamping and cardioplegia, and correction of the acquired heart disease, according to the dynamics of the studied proteins in blood. The minimal blood level of cardiac protein, binding aliphatic acids after coronary by-pass surgery on the working heart witnesses about negative influence of crystalloid hypothermic cardioplegia on coronary microcirculation.

  19. Associations of blood pressure and arterial compliance with occupational noise exposure in female workers of textile mill

    Institute of Scientific and Technical Information of China (English)

    NI Chun-hui; ZHANG Yu-jun; CHEN Zhi-yong; ZHOU Yin; ZHOU Jian-wei; Pan Jing-jing; LIU Nian; WANG Jun; LIANG Chen-ke; ZHANG Zhi-zhong

    2007-01-01

    Background There are few studies on the arterial compliance of noise exposure. The purpose of this study was to understand the relationship between hearing loss, blood pressure and arterial compliance of female workers who exposed to occupational noise in a textile mill.Methods The noise levels in the workplace were measured with a HS6288 sound level meter. Cumulated noise exposure (CNE) was calculated according to the noise intensity and the exposure period. Hearing ability and arterial compliance were measured in 618 noise exposed workers. The database was set up with EpiData and the statistical analysis was performed with SAS software 9.1.3.Results The noise levels were 80.1dB(A) to 113.5dB(A), of which the levels at 92.5% of the noise monitoring sites were over the national standard. The incidence of high frequency hearing loss (HFHL) was 24.43% and language frequency hearing impairment (LFHI) was 0.81%. The incidence of hypertension was 7.93%. Both systolic blood pressure (SBP)and diastolic blood pressure (DBP) in the high frequency hearing loss group were significantly higher than those in the normal hearing group (P<0.05), while C1 (large artery compliance) and C2 (small artery compliance) were significantly lower (P<0.05). The high frequency hearing threshold (HFHT) of the hypertension group was significantly higher than in the normal blood pressure group (P<0.05), while C1 and C2 were significantly lower (P<0.05). C1 and C2 had a negative correlation with HFHT, SBP, DBP, mean of arterial pressure (MAP), pulse pressure (PP) and pulse rate (PR) (P<0.05).The multiple regression analyses showed that blood pressure and PR were the main influencing factors on C1 and C2.LFHT was an influence on C2 and HFHT on C1.Conclusions Textile mill noise pollution is very serious and has an obvious influence on worker's auditory function. The female workers with Iow artery compliance or with high blood pressure might be suffering from hearing loss; those with noise

  20. Understanding How Space Travel Affects Blood Vessels: Arterial Remodeling and Functional Adaptations Induced by Microgravity

    Science.gov (United States)

    Delp, Michael; Vasques, Marilyn; Aquilina, Rudy (Technical Monitor)

    2002-01-01

    Ever rise quickly from the couch to get something from the kitchen and suddenly feel dizzy? With a low heart rate and relaxed muscles, the cardiovascular system does not immediately provide the resistance necessary to keep enough blood going to your head. Gravity wins, at least for a short time, before your heart and blood vessels can respond to the sudden change in position and correct the situation. Actually, the human cardiovascular system is quite well adapted to the constant gravitational force of the Earth. When standing, vessels in the legs constrict to prevent blood from collecting in the lower extremities. In the space environment, the usual head-to-foot blood pressure and tissue fluid gradients that exist during the upright posture on Earth are removed. The subsequent shift in fluids from the lower to the upper portions of the body triggers adaptations within the cardiovascular system to accommodate the new pressure and fluid gradients. In animal models that simulate microgravity, the vessels in the head become more robust while those in the lower limbs become thin and lax. Similar changes may also occur in humans during spaceflight and while these adaptations are appropriate for a microgravity environment, they can cause problems when the astronauts return to Earth or perhaps another planet. Astronauts often develop orthostatic intolerance which means they become dizzy or faint when standing upright. This dizziness can persist for a number of days making routine activities difficult. In an effort to understand the physiological details of these cardiovascular adaptations, Dr. Michael Delp at Texas A&M University, uses the rat as a model for his studies. For the experiment flown on STS-107, he will test the hypothesis that blood vessels in the rats' hindlimbs become thinner, weaker, and constrict less in response to pressure changes and to chemical signals when exposed to microgravity. In addition, he will test the hypothesis that arteries in the brain

  1. Arterial blood pressure and renal sodium excretion in dopamine D3 receptor knockout mice.

    Science.gov (United States)

    Staudacher, Torsten; Pech, Bärbel; Tappe, Michael; Gross, Gerhard; Mühlbauer, Bernd; Luippold, Gerd

    2007-01-01

    Alterations in the dopaminergic system may contribute to the development of hypertension. Recently, it has been reported that pentobarbital-anesthetized mice with deficient dopamine D(3) receptors showed renin-dependent elevation in blood pressure. In a series of experiments, we evaluated the contribution of the dopamine D(3) receptor to the renal sodium excretion and arterial blood pressure behavior in conscious as well as anesthetized dopamine D(3) receptor knockout (-/-) mice. The blood pressure measuring study was designed as a cross-over trial to investigate the influence of different sodium loads. The animals were fed a normal salt diet (0.6% NaCl, NS) for 1 week and afterwards a low (0.2% NaCl, LS) or a high salt diet (4.6% NaCl, HS) for 2 weeks. After the third week, the animals were switched to the corresponding protocol. Systolic blood pressure in conscious (-/-) mice measured by tail-cuff plethysmography was not different from that of wild-type (+/+) animals, irrespective of the time course or the salt diet. In another experiment, challenge of an acute sodium loading per gavage in conscious D(3) receptor (-/-) and (+/+) animals on HS or NS diet did not show significant differences in renal sodium excretion between the two genotypes. Additionally, animals were fed an NS diet for 1 week and an HS diet for another week. As expected, sodium excretion significantly increased after the change from the NS to the HS diet. A slightly lower urinary sodium excretion was observed when comparing D(3) receptor (-/-) mice to their corresponding (+/+) mice, both on an HS diet. Clearance experiments with anesthetized D(3) receptor (-/-) and (+/+) mice were performed to investigate the renal sodium excretion capacity, when exposed to a moderate volume expansion (VE). Urinary sodium excretion increased in response to the VE; however, no difference were observed between the two genotypes. Taking these results together, we conclude that in the present animal model renal

  2. Blood Pressure Control in Smokers with Arterial Hypertension Who Switched to Electronic Cigarettes

    Directory of Open Access Journals (Sweden)

    Riccardo Polosa

    2016-11-01

    Full Text Available Electronic cigarettes (ECs are battery-operated devices designed to vaporise nicotine, which may help smokers with quitting or reducing their tobacco consumption. No data is available regarding the health effects of ECs use among smokers with arterial hypertension and whether regular use results in blood pressure (BP changes. We investigated long-term changes in resting BP and level of BP control in hypertensive smokers who quit or reduced substantially their tobacco consumption by switching to ECs. A medical records review of patients with hypertension was conducted to identify patients reporting regular daily use of ECs on at least two consecutive follow-up visits. Regularly smoking hypertensive patients were included as a reference group. A marked reduction in cigarette consumption was observed in ECs users (n = 43 though consumption remained unchanged in the control group (n = 46. Compared to baseline, at 12 months (follow-up visit 2 decline in cigarette consumption was associated with significant reductions in median (25th-, 75th-centile systolic BP (140 (134.5, 144 to 130 (123.5, 138.5 mmHg; p < 0.001 and diastolic BP (86 (78, 90 to 80 (74.5, 90 mmHg; p = 0.006. No significant changes were observed in the control group. As expected, decline in cigarette consumption in the ECs users was also associated with improved BP control. The study concludes that regular ECs use may aid smokers with arterial hypertension reduce or abstain from cigarette smoking, with only trivial post-cessation weight gain. This resulted in improvements in systolic and diastolic BP as well as better BP control.

  3. Asymptotic analysis of blood flow in stented arteries: time dependency and direct simulations***

    Directory of Open Access Journals (Sweden)

    Pichon Gostaf Kirill

    2010-12-01

    Full Text Available This work aims to extend in two distinct directions results recently obtained in [10]. In a first step we focus on the possible extension of our results to the time dependent case. Whereas in the second part some preliminary numerical simulations aim to give orders of magnitudes in terms of numerical costs of direct 3D simulations. We consider, in the first part, the time dependent rough problem for a simplified heat equation in a straight channel that mimics the axial velocity under an oscillating pressure gradient. We derive first order approximations with respect to ϵ, the size of the roughness. In order to understand the problem and set up correct boundary layer approximations, we perform a time periodic fourier analysis and check that no frequency can interact with the roughness. We show rigorously on this toy problem that the boundary layers remain stationary in time (independent on the frequency number. Finally we perform numerical tests validating our theoretical approach. In the second part, we determine actual limits, when running three-dimensional blood flow simulations of the non-homogenized stented arteries. We solve the stationary Stokes equations for an artery containing a saccular aneurysm. Consecutive levels of uniform mesh refinement, serve to relate spatial resolution, problem scale, and required computation time. Test computations are presented for femoral side aneurysm, where a simplified ten-wire stent model was placed across the aneurysm throat. We advocate the proposed stent homogenization model, by concluding that an actual computation power is not sufficient to run accurate, direct simulations of a pulsatile flow in stented vessels.

  4. Blood Pressure Control in Smokers with Arterial Hypertension Who Switched to Electronic Cigarettes

    Science.gov (United States)

    Polosa, Riccardo; Morjaria, Jaymin B.; Caponnetto, Pasquale; Battaglia, Eliana; Russo, Cristina; Ciampi, Claudio; Adams, George; Bruno, Cosimo M.

    2016-01-01

    Electronic cigarettes (ECs) are battery-operated devices designed to vaporise nicotine, which may help smokers with quitting or reducing their tobacco consumption. No data is available regarding the health effects of ECs use among smokers with arterial hypertension and whether regular use results in blood pressure (BP) changes. We investigated long-term changes in resting BP and level of BP control in hypertensive smokers who quit or reduced substantially their tobacco consumption by switching to ECs. A medical records review of patients with hypertension was conducted to identify patients reporting regular daily use of ECs on at least two consecutive follow-up visits. Regularly smoking hypertensive patients were included as a reference group. A marked reduction in cigarette consumption was observed in ECs users (n = 43) though consumption remained unchanged in the control group (n = 46). Compared to baseline, at 12 months (follow-up visit 2) decline in cigarette consumption was associated with significant reductions in median (25th-, 75th-centile) systolic BP (140 (134.5, 144) to 130 (123.5, 138.5) mmHg; p < 0.001) and diastolic BP (86 (78, 90) to 80 (74.5, 90) mmHg; p = 0.006). No significant changes were observed in the control group. As expected, decline in cigarette consumption in the ECs users was also associated with improved BP control. The study concludes that regular ECs use may aid smokers with arterial hypertension reduce or abstain from cigarette smoking, with only trivial post-cessation weight gain. This resulted in improvements in systolic and diastolic BP as well as better BP control. PMID:27845734

  5. Mapping Long-Term Functional Changes in Cerebral Blood Flow by Arterial Spin Labeling

    Science.gov (United States)

    Ssali, Tracy; Anazodo, Udunna C.; Bureau, Yves; MacIntosh, Bradley J.; Günther, Matthias; St. Lawrence, Keith

    2016-01-01

    Although arterial spin labeling (ASL) is appealing for mapping long-term changes in functional activity, inter-sessional variations in basal blood flow, arterial transit times (ATTs), and alignment errors, can result in significant false activation when comparing images from separate sessions. By taking steps to reduce these sources of noise, this study assessed the ability of ASL to detect functional CBF changes between sessions. ASL data were collected in three sessions to image ATT, resting CBF and CBF changes associated with motor activation (7 participants). Activation maps were generated using rest and task images acquired in the same session and from sessions separated by up to a month. Good agreement was found when comparing between-session activation maps to within-session activation maps with only a 16% decrease in precision (within-session: 90 ± 7%) and a 13% decrease in the Dice similarity (within-session: 0.75 ± 0.07) coefficient after a month. In addition, voxel-wise reproducibility (within-session: 4.7 ± 4.5%) and reliability (within-session: 0.89 ± 0.20) of resting grey-matter CBF decreased by less than 18% for the between-session analysis relative to within-session values. ATT variability between sessions (5.0 ± 2.7%) was roughly half the between-subject variability, indicating that its effects on longitudinal CBF were minimal. These results demonstrate that conducting voxel-wise analysis on CBF images acquired on different days is feasible with only modest loss in precision, highlighting the potential of ASL for longitudinal studies. PMID:27706218

  6. Autoregulation of cerebral blood flow to changes in arterial pressure in mild Alzheimer's disease.

    Science.gov (United States)

    Zazulia, Allyson R; Videen, Tom O; Morris, John C; Powers, William J

    2010-11-01

    Studies in transgenic mice overexpressing amyloid precursor protein (APP) demonstrate impaired autoregulation of cerebral blood flow (CBF) to changes in arterial pressure and suggest that cerebrovascular dysfunction may be critically important in the development of pathological Alzheimer's disease (AD). Given the relevance of such a finding for guiding hypertension treatment in the elderly, we assessed autoregulation in individuals with AD. Twenty persons aged 75±6 years with very mild or mild symptomatic AD (Clinical Dementia Rating 0.5 or 1.0) underwent (15)O-positron emission tomography (PET) CBF measurements before and after mean arterial pressure (MAP) was lowered from 107±13 to 92±9 mm Hg with intravenous nicardipine; (11)C-PIB-PET imaging and magnetic resonance imaging (MRI) were also obtained. There were no significant differences in mean CBF before and after MAP reduction in the bilateral hemispheres (-0.9±5.2 mL per 100 g per minute, P=0.4, 95% confidence interval (CI)=-3.4 to 1.5), cortical borderzones (-1.9±5.0 mL per 100 g per minute, P=0.10, 95% CI=-4.3 to 0.4), regions of T2W-MRI-defined leukoaraiosis (-0.3±4.4 mL per 100 g per minute, P=0.85, 95% CI=-3.3 to 3.9), or regions of peak (11)C-PIB uptake (-2.5±7.7 mL per 100 g per minute, P=0.30, 95% CI=-7.7 to 2.7). The absence of significant change in CBF with a 10 to 15 mm Hg reduction in MAP within the normal autoregulatory range demonstrates that there is neither a generalized nor local defect of autoregulation in AD.

  7. Effects of Weather and Heliophysical Conditions on Emergency Ambulance Calls for Elevated Arterial Blood Pressure

    Directory of Open Access Journals (Sweden)

    Jone Vencloviene

    2015-02-01

    Full Text Available We hypothesized that weather and space weather conditions were associated with the exacerbation of essential hypertension. The study was conducted during 2009–2010 in the city of Kaunas, Lithuania. We analyzed 13,475 cards from emergency ambulance calls (EACs, in which the conditions for the emergency calls were made coded I.10–I.15. The Kaunas Weather Station provided daily records of air temperature (T, wind speed (WS, relative humidity, and barometric pressure (BP. We evaluated the associations between daily weather variables and daily number of EACs by applying a multivariate Poisson regression. Unfavorable heliophysical conditions (two days after the active-stormy geomagnetic field or the days with solar WS > 600 km/s increased the daily number of elevated arterial blood pressure (EABP by 12% (RR = 1.12; 95% confidence interval (CI 1.04–1.21; and WS ≥ 3.5 knots during days of T < 1.5 °C and T ≥ 12.5 °C by 8% (RR = 1.08; CI 1.04–1.12. An increase of T by 10 °C and an elevation of BP two days after by 10 hPa were associated with a decrease in RR by 3%. An additional effect of T was detected during days of T ≥ 17.5 °C only in females. Women and patients with grade III arterial hypertension at the time of the ambulance call were more sensitive to weather conditions. These results may help in the understanding of the population’s sensitivity to different weather conditions.

  8. Impact of primary percutaneous coronary intervention on blood perfusion in nonculprit artery in patients with anterior ST elevation myocardial infarction

    Institute of Scientific and Technical Information of China (English)

    WANG Jian; LIU Jing-hua; ZHENG Bin; ZHANG Ming; WANG Shao-ping; ZHENG Ze

    2013-01-01

    Background Recent studies have demonstrated that epicardial flow in nonculprit arteries,which has been assumed to be normal,was slowed in the setting of ST-elevation myocardial infarction (STEMI).However,the impact of primary percutaneous coronary intervention (PCI) on blood perfusion in nonculprit arteries in patients with STEMI has not been clarified.The purpose of this study was to investigate the impact of primary PCI on blood perfusion in nonculprit arteries in patients with STEMI and correlated clinical factors.Methods A total of 117 patients with anterior wall STEMI,the culprit artery being the left anterior descending artery (LAD),undergoing primary PCI (the study group) and 100 patients with normal coronary angiography (the control group) were enrolled.To observe the differences of corrected TIMI frame count (cTFC) and myocardial blush grade (MBG) before and after primary PCI in both culprit and nonculprit arteries,the left circumflex coronary artery (LCX),cTFC and MBG in the LAD and LCX were measured in the study group and control group.The study group was divided into three groups; reflow in the culprit artery group (the R group),no reflow in culprit artery group (the NR group),and no reflow in both the culprit artery and nonculprit artery group (the NRB group) according to MBG grade.The level of serum C-reactive protein (CRP),catecholamine,and fibroblast growth factor-21 (FGF21) were assayed.The clinical and angiographic characteristics were also analyzed.Results cTFC (28.1±24.3 vs.20.3±19.3,P <0.05) and MBG in the LCX were different in the study group compared to the control group before primary PCI.cTFC (25.2±22.3 vs.28.1±24.3,P <0.05) and the MBG level in the LCX were improved after successful primary PCI,but were not recovered to the normal level.Patients with no reflow in the culprit artery had a higher incidence of no-reflow in the nonculprit artery (78% vs.19%,P <0.0001),and the levels of CRP ((3.29±1.31) mg/dl vs.(2.51±1.14) mg

  9. A novel framework for fluid/structure interaction in rapid subject specific simulations of blood flow in coronary artery bifurcations

    Directory of Open Access Journals (Sweden)

    Blagojević Milan

    2014-01-01

    Full Text Available Background/Aim. Practical difficulties, particularly long model development time, have limited the types and applicability of computational fluid dynamics simulations in numerical modeling of blood flow in serial manner. In these simulations, the most revealing flow parameters are the endothelial shear stress distribution and oscillatory shear index. The aim of this study was analyze their role in the diagnosis of the occurrence and prognosis of plaque development in coronary artery bifurcations. Methods. We developed a novel modeling technique for rapid cardiovascular hemodynamic simulations taking into account interactions between fluid domain (blood and solid domain (artery wall. Two numerical models that represent the observed subdomains of an arbitrary patient-specific coronary artery bifurcation were created using multi-slice computed tomography (MSCT coronagraphy and ultrasound measurements of blood velocity. Coronary flow using an in-house finite element solver PAK-FS was solved. Results. Overall behavior of coronary artery bifurcation during one cardiac cycle is described by: velocity, pressure, endothelial shear stress, oscillatory shear index, stress in arterial wall and nodal displacements. The places where (a endothelial shear stress is less than 1.5, and (b oscillatory shear index is very small (close or equal to 0 are prone to plaque genesis. Conclusion. Finite element simulation of fluid-structure interaction was used to investigate patient-specific flow dynamics and wall mechanics at coronary artery bifurcations. Simulation model revealed that lateral walls of the main branch and lateral walls distal to the carina are exposed to low endothelial shear stress which is a predilection site for development of atherosclerosis. This conclusion is confirmed by the low values of oscillatory shear index in those places.

  10. COMPARISON OF HIGH-DEFINITION OSCILLOMETRIC AND DIRECT ARTERIAL BLOOD PRESSURE MEASUREMENT IN ANESTHETIZED CHEETAHS (ACINONYX JUBATUS).

    Science.gov (United States)

    Sant Cassia, Emma V; Boswood, Adrian; Tordiffe, Adrian S W

    2015-09-01

    Blood pressure measurement reveals important insights into the health of conscious and anesthetized individuals. This is of particular interest in cheetahs (Acinonyx jubatus), which in captivity are known to suffer from chronic diseases that may be associated with hypertension and which often require immobilization for transport or veterinary treatment. Invasive testing methods are considered the gold standard but are not practical in many settings. Consequently, it is important to evaluate the use of noninvasive methods in this species. Measurements for systolic, diastolic, and mean arterial pressure obtained using high-definition oscillometry (HDO) at the coccygeal artery were compared to simultaneous direct measurements obtained via catheterization of the femoral or dorsal pedal artery in eight anesthetized captive cheetahs during nine anesthetic events. Overall, HDO and direct measurements agreed most closely for mean arterial pressure, and the poorest agreement was observed for systolic pressure. There was a tendency for low diastolic pressures to be underestimated and for high diastolic pressures to be overestimated. Across all three parameters, HDO measurements from the tail overestimated directly measured pressures in the femoral artery and underestimated those in the dorsal pedal artery. HDO agreed most closely with directly measured dorsal pedal pressures. Mean arterial pressure showed the greatest precision (standard deviation of 10.2 mm Hg) and lowest bias (-1.2 mm Hg), with 75.9% of readings within 10 mm Hg of the direct dorsal pedal pressure. Agreement with systolic pressure was hindered by a high bias (-10.4 mm Hg), but if a correction factor of +10 mm Hg was applied to all systolic measurements, agreement was improved and 65.7% of readings were within 10 mm Hg of the direct pressure. When compared to criteria defined by the American College of Veterinary Internal Medicine for validation of blood pressure devices, results were favorable, but a

  11. Cerebral small-resistance artery structure and cerebral blood flow in normotensive subjects and hypertensive patients

    Energy Technology Data Exchange (ETDEWEB)

    De Ciuceis, Carolina; Porteri, Enzo; Rizzoni, Damiano; Boari, Gianluca E.M.; Rosei, Enrico Agabiti [University of Brescia, Clinica Medica, Department of Clinical and Experimental Sciences, Brescia (Italy); Cornali, Claudio; Mardighian, Dikran; Fontanella, Marco M. [University of Brescia, Section of Neurosurgery, Department of Medical and Surgical Specialties, Radiological Sciences and Public Health, Brescia (Italy); Pinardi, Chiara [Spedali Civili, Medical Physics Unit, Brescia (Italy); University of Brescia, Section of Neuroradiology, Department of Medical and Surgical Specialties, Radiological Sciences and Public Health, Brescia (Italy); Rodella, Luigi F.; Rezzani, Rita [University of Brescia, Section of Anatomy, Department of Clinical and Experimental Sciences, Brescia (Italy); Gasparotti, Roberto [University of Brescia, Section of Neurosurgery, Department of Medical and Surgical Specialties, Radiological Sciences and Public Health, Brescia (Italy); University of Brescia, Section of Neuroradiology, Department of Medical and Surgical Specialties, Radiological Sciences and Public Health, Brescia (Italy)

    2014-12-15

    The aim of this study was to prospectively investigate whether the structure of cerebral small-resistance arteries is related to cerebral perfusion parameters as measured with dynamic susceptibility-weighted contrast magnetic resonance imaging (DSC-MRI) in a selected cohort of hypertensive and normotensive patients. Ten hypertensive and 10 normotensive patients were included in the study. All patients underwent neurosurgical intervention for an intracranial tumor and were investigated with DSC-MRI at 1.5 T. Cerebral small-resistance arteries were dissected from a small portion of morphologically normal cerebral tissue and mounted on an isometric myograph for the measurement of the media-to-lumen (M/L) ratio. A quantitative assessment of cerebral blood flow (CBF) and volume (CBV) was performed with a region-of-interest approach. Correlation coefficients were calculated for normally distributed variables. The institutional review board approved the study, and informed consent was obtained from all patients. Compared with normotensive subjects, hypertensive patients had significantly lower regional CBF (mL/100 g/min) in the cortical grey matter (55.63 ± 1.90 vs 58.37 ± 2.19, p < 0.05), basal ganglia (53.34 ± 4.39 vs 58.22. ± 4.33, p < 0.05), thalami (50.65 ± 3.23 vs 57.56 ± 4.45, p < 0.01), subcortical white matter (19.32 ± 2.54 vs 22.24 ± 1.9, p < 0.05), greater M/L ratio (0.099 ± 0.013 vs 0.085 ± 0.012, p < 0.05), and lower microvessel density (1.66 ± 0.67 vs 2.52 ± 1.28, p < 0.05). A statistically significant negative correlation was observed between M/L ratio of cerebral arteries and CBF in the cortical grey matter (r = -0.516, p < 0.05), basal ganglia (r = -0.521, p < 0.05), thalami (r = -0.527 p < 0.05), and subcortical white matter (r = -0.612, p < 0.01). Our results indicate that microvascular structure might play a role in controlling CBF, with possible clinical consequences. (orig.)

  12. Short-term effects of nitrate-rich green leafy vegetables on blood pressure and arterial stiffness in individuals with high-normal blood pressure.

    Science.gov (United States)

    Bondonno, Catherine P; Liu, Alex H; Croft, Kevin D; Ward, Natalie C; Yang, Xingbin; Considine, Michael J; Puddey, Ian B; Woodman, Richard J; Hodgson, Jonathan M

    2014-12-01

    Evidence for a beneficial effect of dietary nitrate, through the nitrate-nitrite-NO pathway, on measures of cardiovascular function in healthy individuals is accumulating. It is less clear whether increased dietary nitrate intake from green leafy vegetables would have similar beneficial vascular effects in those at increased risk of developing hypertension. Our aim was to assess the effects of short-term regular consumption of increased nitrate from green leafy vegetables on blood pressure and arterial stiffness in individuals with high-normal blood pressure. Thirty-eight men and women ages 30-70 years with systolic blood pressure 120 to 139 mm Hg were recruited to a randomized controlled crossover trial. The effects of a 7-day high-nitrate diet intervention (increased nitrate intake by at least 300 mg/day from green leafy vegetables) were compared to a 7-day low-nitrate diet intervention. Outcome measures included pre- and postintervention salivary and plasma nitrate and nitrite concentrations; ambulatory, home, and office blood pressure; augmentation index; and carotid-femoral pulse wave velocity. The high-nitrate diet intervention resulted in at least a fourfold increase in salivary and plasma nitrate and nitrite (Pblood pressure and arterial stiffness were not different between the high-nitrate diet and the low-nitrate diet. Increasing dietary nitrate intake in those with high-normal blood pressure and at increased risk of hypertension may not be an effective short-term strategy to lower blood pressure.

  13. Contribution of spiral artery blood flow changes assessed by transvaginal color Doppler sonography for predicting endometrial pathologies

    Directory of Open Access Journals (Sweden)

    Suna Kabil Kucur

    2013-01-01

    Full Text Available ive: To investigate the diagnostic value of blood flow measurements in spiral artery by transvaginal color Doppler sonography (CDS in predicting endometrial pathologies.Methods: Ninety-seven patients presenting with abnormal uterine bleeding and requiring endometrial assessment were included in this prospective observational study. Endometrial thickness, structure and echogenicity were recorded. Pulsatility index (PI and resistive index (RI of the spiral artery were measured by transvaginal CDS. Endometrial sampling was performed for all subjects. Sonographic and hystopathologic findings were compared.Results: The histopathological diagnoses were as follows; 39 cases (40.2% endometrial polyp, 9 cases (9.3% endometrial hyperplasia, 10 cases (10.3 submucous myoma, 7 cases (7.2% endometrium cancer, and 32 cases (33% nonspecific findings. The spiral artery PI in endometrium cancer group was highly significantly lower than other groups (p<0.01. The spiral artery RI was also significantly lower in the patients with malignant histology (p<0.05. Conclusion: Endometrial pathologies are associated significantly with endometrial spiral artery Doppler changes.Key words: Spiral artery, Doppler ultrasonography, endometrium

  14. Comparison of the effects of antihypertensive agents on central blood pressure and arterial stiffness in isolated systolic hypertension.

    Science.gov (United States)

    Mackenzie, Isla S; McEniery, Carmel M; Dhakam, Zahid; Brown, Morris J; Cockcroft, John R; Wilkinson, Ian B

    2009-08-01

    Isolated systolic hypertension is an important risk factor for cardiovascular disease and results primarily from elastic artery stiffening. Although various drug therapies are used to lower peripheral blood pressure (BP) in patients with isolated systolic hypertension, the effects of the 4 major classes of antihypertensive agents on central BP, pulse pressure (PP) amplification, and arterial stiffness in this condition are not clear. Fifty-nine patients over the age of 60 years with untreated isolated systolic hypertension (systolic BP > or =140 mm Hg and diastolic BP hypertension, the choice of therapy may be influenced by these findings in the future.

  15. Differential increases in blood flow velocity in the middle cerebral artery after tourniquet deflation during sevoflurane, isoflurane or propofol anaesthesia.

    Science.gov (United States)

    Kadoi, Y; Kawauchi, C H; Ide, M; Saito, S; Mizutani, A

    2009-07-01

    The purpose of this study was to examine the comparative effects of sevoflurane, isoflurane or propofol on cerebral blood flow velocity after tourniquet deflation during orthopaedic surgery. Thirty patients undergoing elective orthopaedic surgery were randomly divided into sevoflurane, isoflurane and propofol groups. Anaesthesia was maintained with sevoflurane, isoflurane or propofol infusion in 33% oxygen and 67% nitrous oxide, in whatever concentrations were necessary to keep bispectral index values between 45 and 50. Ventilatory rate or tidal volume was adjusted to target PaCO2 of 35 mmHg. A 2.0 MHz transcranial Doppler probe was attached to the patient's head at the temporal window and mean blood flow velocity in the middle cerebral artery was continuously measured. The extremity was exsanguinated with an Esmarch bandage and the pneumatic tourniquet was inflated to a pressure of 450 mmHg. Arterial blood pressure, heart rate, velocity in the middle cerebral artery and arterial blood gas analysis were measured every minute for 10 minutes after release of the tourniquet in all three groups. Velocity in the middle cerebral artery in the three groups increased for five minutes after tourniquet deflation. Because of the different cerebrovascular effects of the three agents, the degree of increase in flow velocity in the isoflurane group was greater than in the other two groups, the change in flow velocity in the propofol group being the lowest (at three minutes after deflation 40 +/- 7%, 32 +/- 6% and 28 +/- 10% in the isoflurane, sevoflurane and propofol groups respectively, P < 0.05).

  16. Assessment of blood flow velocity and pulsatility in cerebral perforating arteries with 7-T quantitative flow MRI.

    Science.gov (United States)

    Bouvy, W H; Geurts, L J; Kuijf, H J; Luijten, P R; Kappelle, L J; Biessels, G J; Zwanenburg, J J M

    2016-09-01

    Thus far, blood flow velocity measurements with MRI have only been feasible in large cerebral blood vessels. High-field-strength MRI may now permit velocity measurements in much smaller arteries. The aim of this proof of principle study was to measure the blood flow velocity and pulsatility of cerebral perforating arteries with 7-T MRI. A two-dimensional (2D), single-slice quantitative flow (Qflow) sequence was used to measure blood flow velocities during the cardiac cycle in perforating arteries in the basal ganglia (BG) and semioval centre (CSO), from which a mean normalised pulsatility index (PI) per region was calculated (n = 6 human subjects, aged 23-29 years). The precision of the measurements was determined by repeated imaging and performance of a Bland-Altman analysis, and confounding effects of partial volume and noise on the measurements were simulated. The median number of arteries included was 14 in CSO and 19 in BG. In CSO, the average velocity per volunteer was in the range 0.5-1.0 cm/s and PI was 0.24-0.39. In BG, the average velocity was in the range 3.9-5.1 cm/s and PI was 0.51-0.62. Between repeated scans, the precision of the average, maximum and minimum velocity per vessel decreased with the size of the arteries, and was relatively low in CSO and BG compared with the M1 segment of the middle cerebral artery. The precision of PI per region was comparable with that of M1. The simulations proved that velocities can be measured in vessels with a diameter of more than 80 µm, but are underestimated as a result of partial volume effects, whilst pulsatility is overestimated. Blood flow velocity and pulsatility in cerebral perforating arteries have been measured directly in vivo for the first time, with moderate to good precision. This may be an interesting metric for the study of haemodynamic changes in aging and cerebral small vessel disease. © 2015 The Authors NMR in Biomedicine Published by John Wiley & Sons Ltd.

  17. Effect of ginger (Zingiber officinale Rosc.) and fenugreek (Trigonella foenumgraecum L.) on blood lipids, blood sugar and platelet aggregation in patients with coronary artery disease.

    Science.gov (United States)

    Bordia, A; Verma, S K; Srivastava, K C

    1997-05-01

    In a placebo-controlled study the effect of ginger and fenugreek was examined on blood lipids, blood sugar, platelet aggregation, fibrinogen and fibrinolytic activity. The subjects included in this study were healthy individuals, patients with coronary artery disease (CAD), and patients with non-insulin-dependent diabetes mellitus (NIDDM) who either had CAD or were without CAD. In patients with CAD powdered ginger administered in a dose of 4 g daily for 3 months did not affect ADP- and epinephrine-induced platelet aggregation. Also, no change in the fibrinolytic activity and fibrinogen level was observed. However, a single dose of 10 g powdered ginger administered to CAD patients produced a significant reduction in platelet aggregation induced by the two agonists. Ginger did not affect the blood lipids and blood sugar. Fenugreek given in a dose of 2.5 g twice daily for 3 months to healthy individuals did not affect the blood lipids and blood sugar (fasting and post prandial). However, administered in the same daily dose for the same duration to CAD patients also with NIDDM, fenugreek decreased significantly the blood lipids (total cholesterol and triglycerides) without affecting the HDL-c. When administered in the same daily dose to NIDDM (non-CAD) patients (mild cases), fenugreek reduced significantly the blood sugar (fasting and post prandial). In severe NIDDM cases, blood sugar (both fasting and post prandial) was only slightly reduced. The changes were not significant. Fenugreek administration did not affect platelet aggregation, fibrinolytic activity and fibrinogen.

  18. Selenium status and GSH-Px activity in semen and blood of boars at different ages used for artificial insemination.

    Science.gov (United States)

    Lasota, B; Błaszczyk, B; Seremak, B; Udała, J

    2004-10-01

    This study was performed to determine the relationship between selenium (Se) content and Se-dependent glutathione peroxidase (GSH-Px) activity in blood and semen, and semen quality of boars at different age used in an artificial insemination (AI) station. Routine macroscopic and microscopic analyses of semen quality were accompanied by measurement of Se content and GSH-Px activity in blood and semen. The Se concentration in blood plasma, seminal fluid and spermatozoa was measured by fluorometric method, the GSH-Px activity by a method based on NADPH-coupled reaction. A total of 155 ejaculates and 58 blood samples were investigated. The results of this study showed that there was no direct relationship between the Se content and GSH-Px activity in blood plasma and semen, and semen quality of sexual matured boars. The mechanisms controlling Se content and GSH-Px activity in blood and semen seem to be independent. The age of boars as a differentiating factor for Se content and GSH-Px activity in blood and semen is possible. It is concluded that a determination of Se status and/or GSH-Px activity in organism before Se supplementation is indicated.

  19. Slip Effects on the Unsteady MHD Pulsatile Blood Flow through Porous Medium in an Artery under the Effect of Body Acceleration

    Directory of Open Access Journals (Sweden)

    Islam M. Eldesoky

    2012-01-01

    Full Text Available Unsteady pulsatile flow of blood through porous medium in an artery has been studied under the influence of periodic body acceleration and slip condition in the presence of magnetic field considering blood as an incompressible electrically conducting fluid. An analytical solution of the equation of motion is obtained by applying the Laplace transform. With a view to illustrating the applicability of the mathematical model developed here, the analytic explicit expressions of axial velocity, wall shear stress, and fluid acceleration are given. The slip condition plays an important role in shear skin, spurt, and hysteresis effects. The fluids that exhibit boundary slip have important technological applications such as in polishing valves of artificial heart and internal cavities. The effects of slip condition, magnetic field, porous medium, and body acceleration have been discussed. The obtained results, for different values of parameters into the problem under consideration, show that the flow is appreciably influenced by the presence of Knudsen number of slip condition, permeability parameter of porous medium, Hartmann number of magnetic field, and frequency of periodic body acceleration. The study is useful for evaluating the role of porosity and slip condition when the body is subjected to magnetic resonance imaging (MRI.

  20. The Effect of High Dose Cholecalciferol on Arterial Stiffness and Peripheral and Central Blood Pressure in Healthy Humans

    DEFF Research Database (Denmark)

    Bressendorff, Iain; Brandi, Lisbet; Schou, Morten

    2016-01-01

    and blood pressure in healthy normotensive adults. METHODS: 40 healthy adults were randomised in this double-blinded study to either oral cholecalciferol 3000 IU/day or matching placebo and were followed for 16 weeks to examine any effects on pulse wave velocity (PWV), augmentation index (AIx), peripheral...... and central blood pressure and 24-hour ambulatory blood pressure. RESULTS: 22 subjects in the cholecalciferol arm and 18 subjects in the placebo arm completed the 16 weeks of follow-up. There was no difference in changes in PWV, AIx corrected for heart rate or central or peripheral blood pressure between...... the two groups. There was no correlation between serum 25-hydroxy vitamin D and any of these parameters. CONCLUSIONS: Oral cholecalciferol 3000 IU/day does not affect arterial stiffness or blood pressure after 16 weeks of treatment in healthy normotensive adults. TRIAL REGISTRATION: ClinicalTrials.gov NCT...

  1. Examination of nanoparticles as a drug carrier on blood flow through catheterized composite stenosed artery with permeable walls.

    Science.gov (United States)

    Ijaz, S; Nadeem, S

    2016-09-01

    In this paper, we have discussed the influence of copper nanoparticles on a blood flow through composite stenosed artery with permeable walls. The nature of blood is discussed mathematically by considering it as viscous nanofluid. The study is carried out for a blood vessel under mild stenosis approximations and expressions of the temperature, velocity, resistance impedance to flow, wall shear stress and the pressure gradient is obtained by using corresponding boundary conditions. Results for the effects of permeability on blood flow through composite stenosis have been discussed graphically. The considered analysis also summarizes that the drug copper nanoparticles are efficient to reduce hemodynamics of stenosis and could be helpful to predict important uses for biomedical applications. Results indicate that nanoparticles are helpful as drug carriers to minimize the effects of resistance impedance to blood flow or coagulation factors due to stenosis.

  2. Reduced blood pressure of CFTR-F508del carriers correlates with diminished arterial reactivity rather than circulating blood volume in mice.

    Directory of Open Access Journals (Sweden)

    Veronica A Peotta

    Full Text Available The F508del mutation of the cystic fibrosis transmembrane conductance regulator (CFTR is the most common cause of cystic fibrosis (CF. Both CF patients and F508del carriers have decreased blood pressure. While this has been attributed to salt depletion, recent studies have shown F508del expression interferes with smooth muscle cell calcium mobilization. We tested the hypothesis that carriers of the F508del mutation have lower adult blood pressures and reduced aortic contractility without a reduction in circulating blood volume. By radiotelemetry, F508del heterozygous mice had significantly lower arterial pressures than wild-type C57BL/6 controls, with the greatest effect seen at the time of dark-to-light cycle transition (mean difference of 10 mmHg. To replicate the vascular effects of sympathetic arousal, isoproterenol and epinephrine were co-infused, and F508del mice again had significantly reduced arterial pressures. Aortas isolated from F508del heterozygous mice had significantly decreased constriction to noradrenaline (0.9 ± 0.2 versus 2.9 ± 0.7 mN. Inhibition of wild-type CFTR or the inositol triphosphate receptor replicated the phenotype of F508del aortas. CFTR carrier status did not alter circulating blood volume. We conclude the CFTR-F508del mutation decreases aortic contractility and lowers arterial pressures. As a cAMP-activated chloride channel that facilitates calcium mobilization, we speculate wild-type CFTR co-activation during adrenergic receptor stimulation buffers the vasodilatory response to catecholamines, and loss of this compensatory vasoconstrictor tone may contribute to the lower arterial pressures seen in heterozygote carriers of a CFTR-F508del mutation.

  3. Peripheral Blood Lymphocyte Depletion After Hepatic Arterial {sup 90}Yttrium Microsphere Therapy for Hepatocellular Carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Carr, Brian I., E-mail: brianicarr@hotmail.com [Department of Surgery, University of Pittsburgh Medical Center, Pittsburgh, PA and Department of Nutrition and Exptl Biology, Saverio De Bellis Medical Research Institute, Castellana Grotte, Bari (Italy); Metes, Diana M. [Department of Surgery, University of Pittsburgh Medical Center, Pittsburgh, PA and Department of Nutrition and Exptl Biology, Saverio De Bellis Medical Research Institute, Castellana Grotte, Bari (Italy)

    2012-03-01

    Purpose: The short- and long-term effects of {sup 90}Yttrium microspheres therapy for hepatocellular carcinoma (HCC) on peripheral blood lymphocytes are unknown and were therefore examined. Methods and Materials: Ninety-two HCC patients were enrolled in a {sup 90}Yttrium therapy study and routine blood counts were examined as part of standard clinical monitoring. Results: We found an early, profound, and prolonged lymphopenia. In a subsequent cohort of 25 additional HCC patients, prospective flow cytometric immune-monitoring analysis was performed to identify specific changes on distinct lymphocyte subsets (i.e., CD3, CD4, CD8 T, and CD19 B lymphocytes) and NK cells absolute numbers, in addition to the granulocytes and platelets subsets. We found that the pretreatment lymphocyte subset absolute numbers (with the exception of NK cells) had a tendency to be lower compared with healthy control values, but no significant differences were detected between groups. Posttherapy follow-up revealed that overall, all lymphocyte subsets, except for NK cells, were significantly (>50% from pretherapy values), promptly (as early as 24 h) and persistently (up to 30 months) depleted post-{sup 90}Yttrium microspheres therapy. In contrast, granulocytes increased rapidly (24 h) to compensate for lymphocyte depletion, and remained increased at 1-year after therapy. We further stratified patients into two groups, according to survival at 1 year. We found that lack of recovery of CD19, CD3, CD8, and especially CD4 T cells was linked to poor patient survival. No fungal or bacterial infections were noted during the 30-month follow-up period. Conclusions: The results show that lymphocytes (and not granulocytes, platelets, or NK cells) are sensitive to hepatic arterial {sup 90}Yttrium without associated clinical toxicity, and lack of lymphocyte recovery (possibly leading to dysregulation of adaptive cellular immunity) posttherapy indicates poor survival.

  4. An artificial pancreas for automated blood glucose control in patients with Type 1 diabetes

    DEFF Research Database (Denmark)

    Schmidt, Signe; Boiroux, Dimitri; Ranjan, Ajenthen;

    2015-01-01

    Automated glucose control in patients with Type 1 diabetes is much-coveted by patients, relatives and healthcare professionals. It is the expectation that a system for automated control, also know as an artificial pancreas, will improve glucose control, reduce the risk of diabetes complications a....... This review gives an introduction to recent progress, challenges and future prospects within the field of artificial pancreas research....

  5. Arterial Blood Gases, Electrolytes and Metabolic Indices Associated with Hemorrhagic Shock: Inter-and Intrainbred Rat Strain Variation

    Science.gov (United States)

    2013-03-07

    cellular changes and compensatory responses. Such ABM include arterial blood gases ( PaO2 , PaCO2, oxygen content); electrolytes (potassium, sodium, cal...1.34 SaO2) (0.003 PaO2 ) where PaO2 arterial oxygen pressure, and SaO2 arterial oxygen saturation. Oxygen content reflects the total volume...TCO2, 2.4%, 2.3%; pH, 0.02%, 0.08%; BE, 10.8%, 21.6%; Na, 0.0%, 0.4%; K, 2.0%, 0.9%; glucose, 1.4%, 2.3%; Ca, 0.8%, 1.2%; PaO2 , 3.4%, 1.3%; oxygen

  6. A benchmark study of numerical schemes for one-dimensional arterial blood flow modelling.

    Science.gov (United States)

    Boileau, Etienne; Nithiarasu, Perumal; Blanco, Pablo J; Müller, Lucas O; Fossan, Fredrik Eikeland; Hellevik, Leif Rune; Donders, Wouter P; Huberts, Wouter; Willemet, Marie; Alastruey, Jordi

    2015-10-01

    Haemodynamical simulations using one-dimensional (1D) computational models exhibit many of the features of the systemic circulation under normal and diseased conditions. Recent interest in verifying 1D numerical schemes has led to the development of alternative experimental setups and the use of three-dimensional numerical models to acquire data not easily measured in vivo. In most studies to date, only one particular 1D scheme is tested. In this paper, we present a systematic comparison of six commonly used numerical schemes for 1D blood flow modelling: discontinuous Galerkin, locally conservative Galerkin, Galerkin least-squares finite element method, finite volume method, finite difference MacCormack method and a simplified trapezium rule method. Comparisons are made in a series of six benchmark test cases with an increasing degree of complexity. The accuracy of the numerical schemes is assessed by comparison with theoretical results, three-dimensional numerical data in compatible domains with distensible walls or experimental data in a network of silicone tubes. Results show a good agreement among all numerical schemes and their ability to capture the main features of pressure, flow and area waveforms in large arteries. All the information used in this study, including the input data for all benchmark cases, experimental data where available and numerical solutions for each scheme, is made publicly available online, providing a comprehensive reference data set to support the development of 1D models and numerical schemes.

  7. [Effects of procaterol on arterial blood gas and pulmonary function in asthmatic children].

    Science.gov (United States)

    Obata, T; Masaki, T; Iikura, Y

    1990-12-01

    We examined the changes in arterial blood gas, FEV1 and V50 after the inhalation of procaterol on 19 occasions in 16 asthmatic children. The initial value of PaO2 had statistically significant correlation with the initial values of %FEV1 and %V50. PaO2 fell down in 11 out of 19 (57.9%) and remarkably decreased more than 5 mmHg in 6 out of 19 (31.6%). The fall in PaO2 was most significant at 5 min after the inhalation in almost subjects. The changes in PaO2 after the inhalation had good correlation with the initial value of %FEV1 and %V50. The initial values were quite lower in the patients with decreased PaO2 more than 5 mmHg than those with increased PaO2. Severe patients showed statistically low values of the initial PaO2 and %V50 and showed a fall in PaO2 after inhalation compared with moderate patients. An increase in A-aDO2 elicited that deteriorations of V/Q ratio caused a decrease in PaO2 after inhalation. There were no significant changes in heart rates and no complaints of nausea, headache or tremor.

  8. Influence of magnetic field and Hall currents on blood flow through a stenotic artery

    Institute of Scientific and Technical Information of China (English)

    Kh. S. Mekheimer; M.A. El Kot

    2008-01-01

    A micropolar model for blood simulating magnetohydrodynamic flow through a horizontally nonsymmetric but vertically symmetric artery with a mild stenosis is pre- sented. To estimate the effect of the stenosis shape, a suitable geometry has been consid- ered such that the horizontal shape of the stenosis can easily be changed just by varying a parameter referred to as the shape parameter. Flow parameters, such as velocity, the resistance to flow (the resistance impedance), the wall shear stress distribution in the stenotic region, and its magnitude at the maximum height of the stenosis (stenosis throat), have been computed for different shape parameters, the Hartmann number and the Hall parameter. This shows that the resistance to flow decreases with the increasing values of the parameter determining the stenosis shape and the Hall parameter, while it increases with the increasing Hartmann number. The wall shear stress and the shearing stress on the wall at the maximum height of the stenosis possess an inverse characteristic to the resistance to flow with respect to any given value of the Hartmann number and the Hall parameter. Finally, the effect of the Hartmann number and the Hall parameter on the horizontal velocity is examined.

  9. Alterations in Arterial Blood Parameters in Patients with Liver Cirrhosis and Ascites

    Directory of Open Access Journals (Sweden)

    Konstantinos Charalabopoulos, Dimitrios Peschos, Leonidas Zoganas, George Bablekos, Christos Golias, Alexander Charalabopoulos, Dimitrios Stagikas, Angi Karakosta, Athanasios Papathanasopoulos, George Karachalios, Anna Batistatou

    2007-01-01

    Full Text Available In cirrhotic patients, in addition to hepatocytes and Kuppfer cells dysfunction circulatory anatomic shunt and ventilation/perfusion (VA/ Q ratio abnormalities can induce decrease in partial pressure of oxygen in arterial blood (PaO2, in oxygen saturation of hemoglobin (SaO2 as well as various acid-base disturbances. We studied 49 cases of liver cirrhosis (LC with ascites compared to 50 normal controls. Causes were: posthepatic 37 (75.51%, alcoholic 7 (14.24%, cardiac 2 (4.08%, and cryptogenic 3 (6.12%. Complications were: upper gastrointestinal bleeding 24 (48.97, hepatic encephalopathy 20 (40.81%, gastritis 28 (57.14%, hepatoma 5 (10.2%, renal hepatic syndrome 2 (4.01%, HbsAg (+ 24 (48.97%, and hepatic pleural effusions 7 (14.28%. Average PaO2 and SaO2 were 75.2 mmHg and 94.5 mmHg, respectively, compared to 94.2 mmHg and 97.1 mmHg of the control group, respectively (p value in both PaO2 and SaO2 was pA/Q inequality can induce a decrease in PaO2 and SaO2 as well as various acid-base disturbances. As a result, pulmonary resistance is impaired and patients more likely succumb to infections and adult respiratory distress syndrome.

  10. Arterial line pressure control enhanced extracorporeal blood flow prescription in hemodialysis patients

    Directory of Open Access Journals (Sweden)

    Rosales Laura

    2008-11-01

    Full Text Available Abstract Background In hemodialysis, extracorporeal blood flow (Qb recommendation is 300–500 mL/min. To achieve the best Qb, we based our prescription on dynamic arterial line pressure (DALP. Methods This prospective study included 72 patients with catheter Group 1 (G1, 1877 treatments and 35 arterio-venous (AV fistulae Group 2 (G2, 1868 treatments. The dialysis staff was trained to prescribe Qb sufficient to obtain DALP between -200 to -250 mmHg. We measured ionic clearance (IK: mL/min, access recirculation, DALP (mmHg and Qb (mL/min. Six prescription zones were identified: from an optimal A zone (Qb > 400, DALP -200 to -250 to zones with lower Qb E (Qb -199. Results Treatments distribution in A was 695 (37% in G1 vs. 704 (37.7% in G2 (P = 0.7. In B 150 (8% in G1 vs. 458 (24.5% in G2 (P P = 0.62. IK in A was 214 ± 34 (G1 vs. 213 ± 35 (G2 (P = 0.65. IK Anova between G2 zones was: A vs. C and D (P P = 0.02. Conclusion In conclusion, an optimal Qb can de prescribed with DALP of -200 mmHg. Staff adherence to DLAP treatment prescription could be reached up to 81.3% in catheters and 84.1% in AV fistulae.

  11. The micropolar fluid model for blood flow through a tapered artery with a stenosis

    Institute of Scientific and Technical Information of China (English)

    Kh. S. Mekheimer; M. A. El Kot

    2008-01-01

    A micropolar model for axisymmetric blood flow through an axially nonsymmetreic but radially symmetric mild stenosis tapered artery is presented. To estimate the effect of the stenosis shape, a suitable geometry has been considered such that the axial shape of the stenosis can be changed easily just by varying a parameter (referred to as the shape parameter). The model is also used to study the effect of the taper angle φ. Flow parameters such as the velo-city, the resistance to flow (the resistance impedance), the wall shear stress distribution in the stenotic region and its magnitude at the maximum height of the stenosis (stenosis throat) have been computed for different values of the shape parameter n, the taper angle φ, the coupling number N and the micropolar parameter m. It is shown that the resistance to flow decreases with increasing the shape parameter n and the micropolar parameter m while it increases with increasing the coupling number N. So, the magnitude of the resistance impedance is higher for a micropolar fluid than that for a Newtonian fluid model. Finally, the velocity profile, the wall shear stress distribution in the stenotic region and its magni-tude at the maximum height of the stenosis are discussed for different values of the parameters involved on the problem.

  12. Transplantation of mobilized peripheral blood mononuclear cells for peripheral arterial occlusive disease of the lower extremity

    Institute of Scientific and Technical Information of China (English)

    Xiaofeng YANG; Yanxiang WU; Hongmei WANG; Yifeng XU; Bo XU; Xin LU; Yibin ZANG; Fa WANG; Yue ZHANG

    2006-01-01

    Objectives To assess the clinical efficacy, safety, and feasibility of autologous transplantation of mobilized peripheral blood mononuclear cells (PBMNCs) for patients with peripheral arterial occlusive disease (PAOD) of the lower extremity. Methods A total of 152 patients with PAOD of the lower extremity were enrolled into this non-controlled observational study from November 2003 to March 2006. All patients received subcutaneous injections of recombinant human granulocyte colony-stimulating factor (G-CSF, 450600 μg/day) for 5 days in order to mobilize stem/progenitor cells; their PBMNCs were collected and transplanted by multiple intramuscular injections into ischemic limbs. Patients were followed up for at least 12 weeks. Results At 12 weeks, primarymanifestations,including lower limb pain and coldness, were significantly improved in 137 (90.1%) of the patients; limb ulcers improved or healed in 46 (86.8%) of the 53 patients, while 25 of the 48 (47.9%) patients with limb gangrene remained steady or improved. Ankle-brachial index (ABI) improved in 33 (22%) of the cases, and TcPO2 increased in 45 (30%) of the cases. Angiography before treatment, and at 12 weeks after treatment, was performed in 10 of the patients and showed formation of new collateral vessels. No severe adverse effects or complications specifically related to cell transplantation were observed. Conclusion Autologous transplantation of G-CSF-mobilized PBMNCs might be a safe and effective treatment for lower limb ischemic disorder.(J Geriatr Cardiol 2006; 3:178-80.)

  13. Severe hypovitaminosis D in chronic kidney disease: association with blood pressure and coronary artery calcification.

    Science.gov (United States)

    Pillar, Roberta; G Lopes, Miriam Ghedini; Rocha, Lillian Andrade; Cuppari, Lilian; Carvalho, Aluízio B; Draibe, Sérgio A; Canziani, Maria Eugênia F

    2013-05-01

    Hypovitaminosis D occurs early in the course of chronic kidney disease (CKD), and its association with cardiovascular morbidity and mortality is well known. In this study, we aimed to evaluate whether the degree of hypovitaminosis D may differently affect blood pressure (BP) and coronary artery calcification (CAC) in nondialyzed CKD patients. This study included 80 CKD patients with a creatinine clearance between 15 and 60 ml/min/1.73 m(2) and serum 25 hydroxivitamin D [25(OH)D] level hypovitaminosis D, were defined according to the median 25(OH)D value. Patients with severe hypovitaminosis D [25(OH)D hypovitaminosis D [25(OH)D >17.2 ng/ml; M-group]. No differences were found between the S and M-group in terms of diastolic BP and the presence of coronary calcification. In the multiple linear regression analysis, severe hypovitaminosis D was a predictor of 24-h, daytime and nighttime BP after controlling for a number of confounders. The severity of hypovitaminosis D was associated with increased BP in nondialyzed CKD patients. The degree of hypovitaminosis D was not related to CAC, which was equally elevated in both the severe and mild hypovitaminosis D groups.

  14. The mixing rate of the arterial blood pressure waveform Markov chain is correlated with shock index during hemorrhage in anesthetized swine.

    Science.gov (United States)

    Adibuzzaman, Mohammad; Kramer, George C; Galeotti, Loriano; Merrill, Stephen J; Strauss, David G; Scully, Christopher G

    2014-01-01

    Identifying the need for interventions during hemorrhage is complicated due to physiological compensation mechanisms that can stabilize vital signs until a significant amount of blood loss. Physiological systems providing compensation during hemorrhage affect the arterial blood pressure waveform through changes in dynamics and waveform morphology. We investigated the use of Markov chain analysis of the arterial blood pressure waveform to monitor physiological systems changes during hemorrhage. Continuous arterial blood pressure recordings were made on anesthetized swine (N=7) during a 5 min baseline period and during a slow hemorrhage (10 ml/kg over 30 min). Markov chain analysis was applied to 20 sec arterial blood pressure waveform segments with a sliding window. 20 ranges of arterial blood pressure were defined as states and empirical transition probability matrices were determined for each 20 sec segment. The mixing rate (2(nd) largest eigenvalue of the transition probability matrix) was determined for all segments. A change in the mixing rate from baseline estimates was identified during hemorrhage for each animal (median time of 13 min, ~10% estimated blood volume, with minimum and maximum times of 2 and 33 min, respectively). The mixing rate was found to have an inverse correlation with shock index for all 7 animals (median correlation coefficient of -0.95 with minimum and maximum of -0.98 and -0.58, respectively). The Markov chain mixing rate of arterial blood pressure recordings is a novel potential biomarker for monitoring and understanding physiological systems during hemorrhage.

  15. Classification of hypervascular liver lesions based on hepatic artery and portal vein blood supply coefficients calculated from triphasic CT scans.

    Science.gov (United States)

    Boas, F Edward; Kamaya, Aya; Do, Bao; Desser, Terry S; Beaulieu, Christopher F; Vasanawala, Shreyas S; Hwang, Gloria L; Sze, Daniel Y

    2015-04-01

    Perfusion CT of the liver typically involves scanning the liver at least 20 times, resulting in a large radiation dose. We developed and validated a simplified model of tumor blood supply that can be applied to standard triphasic scans and evaluated whether this can be used to distinguish benign and malignant liver lesions. Triphasic CTs of 46 malignant and 32 benign liver lesions were analyzed. For each phase, regions of interest were drawn in the arterially enhancing portion of each lesion, as well as the background liver, aorta, and portal vein. Hepatic artery and portal vein blood supply coefficients for each lesion were then calculated by expressing the enhancement curve of the lesion as a linear combination of the enhancement curves of the aorta and portal vein. Hepatocellular carcinoma (HCC) and hypervascular metastases, on average, both had increased hepatic artery coefficients compared to the background liver. Compared to HCC, benign lesions, on average, had either a greater hepatic artery coefficient (hemangioma) or a greater portal vein coefficient (focal nodular hyperplasia or transient hepatic attenuation difference). Hypervascularity with washout is a key diagnostic criterion for HCC, but it had a sensitivity of 72 % and specificity of 81 % for diagnosing malignancy in our diverse set of liver lesions. The sensitivity for malignancy was increased to 89 % by including enhancing lesions that were hypodense on all phases. The specificity for malignancy was increased to 97 % (p = 0.039) by also examining hepatic artery and portal vein blood supply coefficients, while maintaining a sensitivity of 76 %.

  16. Carotid artery longitudinal wall motion is associated with local blood velocity and left ventricular rotational, but not longitudinal, mechanics.

    Science.gov (United States)

    Au, Jason S; Ditor, David S; MacDonald, Maureen J; Stöhr, Eric J

    2016-07-01

    Recent studies have identified a predictable movement pattern of the common carotid artery wall in the longitudinal direction. While there is evidence that the magnitude of this carotid artery longitudinal wall motion (CALM) is sensitive to cardiovascular health status, little is known about the determinants of CALM The purpose of this integrative study was to evaluate the contribution of left ventricular (LV) cardiac motion and local blood velocity to CALM Simultaneous ultrasound measurements of CALM, common carotid artery mean blood velocity (MBV), and left ventricular motion were performed in ten young, healthy individuals (6 males; 22 ± 1 years). Peak anterograde CALM occurred at a similar time as peak MBV (18.57 ± 3.98% vs. 18.53 ± 2.81% cardiac cycle; t-test: P = 0.94; ICC: 0.79, P longitudinal displacement was not associated with peak CALM (r = 0.11, P = 0.77). These results suggest that the rotational mechanical movement of the LV base may be closely associated with longitudinal mechanics in the carotid artery. This finding may have important implications for interpreting the complex relationship between ventricular and vascular function.

  17. ABO blood group system and the coronary artery disease: an updated systematic review and meta-analysis.

    Science.gov (United States)

    Chen, Zhuo; Yang, Sheng-Hua; Xu, Hao; Li, Jian-Jun

    2016-03-18

    ABO blood group system, a well-known genetic risk factor, has clinically been demonstrated to be linked with thrombotic vascular diseases. However, the relationship between ABO blood group and coronary artery disease (CAD) is still controversial. We here performed an updated meta-analysis of the related studies and tried to elucidate the potential role of ABO blood group as a risk factor for CAD. All detectable case-control and cohort studies comparing the risk of CAD in different ABO blood groups were collected for this analysis through searching PubMed, Embase, and the Cochrane Library. Ultimately, 17 studies covering 225,810 participants were included. The combined results showed that the risk of CAD was significantly higher in blood group A (OR = 1.14, 95% CI = 1.03 to 1.26, p = 0.01) and lower in blood group O (OR = 0.85, 95% CI = 0.78 to 0.94, p = 0.0008). Even when studies merely about myocardial infarction (MI) were removed, the risk of CAD was still significantly higher in blood group A (OR = 1.05, 95% CI = 1.00 to 1.10, p = 0.03) and lower in blood group O (OR = 0.89, 95% CI = 0.85 to 0.93, p < 0.00001). This updated systematic review and meta-analysis indicated that both blood group A and non-O were the risk factors of CAD.

  18. Periodontal disease and inflammatory blood cytokines in patients with stable coronary artery disease

    Directory of Open Access Journals (Sweden)

    Cassio KAMPITS

    Full Text Available ABSTRACT Periodontal disease has been associated with elevations of blood cytokines involved in atherosclerosis in systemically healthy individuals, but little is known about this association in stable cardiovascular patients. The aim of this study was to assess the association between periodontal disease (exposure and blood cytokine levels (outcomes in a target population of patients with stable coronary artery disease (CAD. Material and Methods This cross-sectional study included 91 patients with stable CAD who had been under optimized cardiovascular care. Blood levels of IL-1β, IL-6, IL-8, IL-10, IFN-γ, and TNF-α were measured by Luminex technology. A full-mouth periodontal examination was conducted to record probing depth (PD and clinical attachment (CA loss. Multiple linear regression models, adjusting for gender, body mass index, oral hypoglycemic drugs, smoking, and occurre:nce of acute myocardial infarction were applied. Results CAD patients that experienced major events had higher concentrations of IFN-γ (median: 5.05 pg/mL vs. 3.01 pg/mL; p=0.01, IL-10 (median: 2.33 pg/mL vs. 1.01 pg/mL; p=0.03, and TNF-α (median: 9.17 pg/mL vs. 7.47 pg/mL; p=0.02. Higher numbers of teeth with at least 6 mm of CA loss (R2=0.07 and PD (R2=0.06 were significantly associated with higher IFN-γ log concentrations. Mean CA loss (R2=0.05 and PD (R2=0.06 were significantly related to IL-10 concentrations. Elevated concentrations of TNF-α were associated with higher mean CA loss (R2=0.07. Conclusion Periodontal disease is associated with increased systemic inflammation in stable cardiovascular patients. These findings provide additional evidence supporting the idea that periodontal disease can be a prognostic factor in cardiovascular patients.

  19. Periodontal disease and inflammatory blood cytokines in patients with stable coronary artery disease

    Science.gov (United States)

    KAMPITS, Cassio; MONTENEGRO, Marlon M.; RIBEIRO, Ingrid W. J.; FURTADO, Mariana V.; POLANCZYK, Carisi A.; RÖSING, Cassiano K.; HAAS, Alex. N

    2016-01-01

    ABSTRACT Periodontal disease has been associated with elevations of blood cytokines involved in atherosclerosis in systemically healthy individuals, but little is known about this association in stable cardiovascular patients. The aim of this study was to assess the association between periodontal disease (exposure) and blood cytokine levels (outcomes) in a target population of patients with stable coronary artery disease (CAD). Material and Methods This cross-sectional study included 91 patients with stable CAD who had been under optimized cardiovascular care. Blood levels of IL-1β, IL-6, IL-8, IL-10, IFN-γ, and TNF-α were measured by Luminex technology. A full-mouth periodontal examination was conducted to record probing depth (PD) and clinical attachment (CA) loss. Multiple linear regression models, adjusting for gender, body mass index, oral hypoglycemic drugs, smoking, and occurre:nce of acute myocardial infarction were applied. Results CAD patients that experienced major events had higher concentrations of IFN-γ (median: 5.05 pg/mL vs. 3.01 pg/mL; p=0.01), IL-10 (median: 2.33 pg/mL vs. 1.01 pg/mL; p=0.03), and TNF-α (median: 9.17 pg/mL vs. 7.47 pg/mL; p=0.02). Higher numbers of teeth with at least 6 mm of CA loss (R2=0.07) and PD (R2=0.06) were significantly associated with higher IFN-γ log concentrations. Mean CA loss (R2=0.05) and PD (R2=0.06) were significantly related to IL-10 concentrations. Elevated concentrations of TNF-α were associated with higher mean CA loss (R2=0.07). Conclusion Periodontal disease is associated with increased systemic inflammation in stable cardiovascular patients. These findings provide additional evidence supporting the idea that periodontal disease can be a prognostic factor in cardiovascular patients. PMID:27556206

  20. Effects of unsteadiness and non-Newtonian rheology on blood flow through a tapered time-variant stenotic artery

    Directory of Open Access Journals (Sweden)

    A. Zaman

    2015-03-01

    Full Text Available A two-dimensional model is used to analyze the unsteady pulsatile flow of blood through a tapered artery with stenosis. The rheology of the flowing blood is captured by the constitutive equation of Carreau model. The geometry of the time-variant stenosis has been used to carry out the present analysis. The flow equations are set up under the assumption that the lumen radius is sufficiently smaller than the wavelength of the pulsatile pressure wave. A radial coordinate transformation is employed to immobilize the effect of the vessel wall. The resulting partial differential equations along with the boundary and initial conditions are solved using finite difference method. The dimensionless radial and axial velocity, volumetric flow rate, resistance impedance and wall shear stress are analyzed for normal and diseased artery with particular focus on variation of these quantities with non-Newtonian parameters.

  1. A prospective study of glomerular filtration rate and arterial blood pressure in insulin-dependent diabetics with diabetic nephropathy

    DEFF Research Database (Denmark)

    Parving, H H; Smidt, U M; Friisberg, B

    1981-01-01

    nephropathy. Twelve of the 14 patients had normal serum creatinine levels. None of the patients received antihypertensive treatment. During the mean observation period of 26 months (range 23 to 33 months) GFR decreased from 107 to 87 ml/min/1.73 m2 (p less than 0.001), serum creatinine remained unchanged: 107...... in arterial blood pressure to a hypertensive level is an early feature of diabetic nephropathy in young insulin-dependent diabetics.......Glomerular filtration rate (GFR, single bolus 51Cr-EDTA technique), serum creatinine, proteinuria and arterial blood pressure have been measured prospectively in 14 young onset insulin-dependent diabetics selected by of persistent proteinuria (greater than 0.5 g/day) secondary to diabetic...

  2. The postural reduction in middle cerebral artery blood velocity is not explained by PaCO2

    DEFF Research Database (Denmark)

    Immink, R V; Secher, N H; Roos, C M

    2006-01-01

    In the normocapnic range, middle cerebral artery mean velocity (MCA Vmean) changes approximately 3.5% per mmHg carbon-dioxide tension in arterial blood (PaCO2) and a decrease in PaCO2 will reduce the cerebral blood flow by vasoconstriction (the CO2 reactivity of the brain). When standing up MCA...... Vmean and the end-tidal carbon-dioxide tension (PETCO2) decrease, suggesting that PaCO2 contributes to the reduction in MCA Vmean. In a fixed body position, PETCO2 tracks changes in the PaCO2 but when assuming the upright position, cardiac output (Q) decreases and its distribution over the lung changes...

  3. Effects of heat transfer on MHD flow of blood through an inclined porous artery with stenosis having variable viscosity

    CERN Document Server

    Tripathi, Bhavya

    2016-01-01

    In this paper, effects of heat transfer on the blood flow through a stenosed, inclined non-tapered porous artery subject to the action of external magnetic field is investigated. Viscosity is assumed as variable viscosity with variable Hematocrit throughout the region of the artery. Governing equations have been modeled by taking blood as incompressible magnetohydrodynamic (MHD) Newtonian fluid. The energy equation is formulated by taking an extra factor of the heat source in its equation. The nonlinear momentum equations are simplified under the assumption of mild stenosis. Homotopy perturbation method (HPM) is used to solve nonlinear equations of velocity and temperature profiles. Effects of porosity parameter (Z), applied magnetic field parameter (M), variable hematocrit parameter(Hr), Brinkman number (Br), heat source parameter (Q) and the Grashof number (Gr) on velocity and temperature profiles are discussed graphically.

  4. Rationale and methodology of monitoring ambulatory blood pressure and arterial compliance in the Hypertension in the Very Elderly Trial

    OpenAIRE

    2006-01-01

    OBJECTIVE: This article describes the rationale and methodology for the monitoring of ambulatory blood pressure and arterial compliance in hypertensive patients aged 80 years and above. This is a side project of the Hypertension in the Very Elderly Trial. METHODS: The hypertension in the Very Elderly Trial is a multicentre, double-blind, randomized, placebo-controlled trial aiming to investigate the effect of active treatment on cardiovascular and other outcomes in hypertensive patients aged ...

  5. Acid-base indicators in the venous and arterial blood of horses affected by recurrent airway obstruction (RAO).

    Science.gov (United States)

    Stopyra, A; Sobiech, P; Waclawska-Matyjasik, A

    2012-01-01

    The acid-base equilibrium is closely linked to gas exchange in the lungs, and respiratory exchange ratios are used to evaluate respiratory effectiveness and tissue oxygen levels. Acid-base indicators are determined in both arterial and venous blood samples. This study compares the usefulness of acid-base indicators of venous and arterial blood in monitoring the condition of horses with recurrent airway obstruction. Prior to treatment involving bronchodilating glucocorticoids, expectorant and mucolytic drugs, more pronounced changes were observed in venous blood (pH 7.283, pCO2 61.92 mmHg, pO2 35.541 mmHg, HCO3- 31.933 mmHg, BE 2.933 mmol/l, O2SAT 58.366%, ctCO2 38.333 mmol/l) than in arterial blood (pH 7.309, pCO2 53.478 mmHg, pO2 90.856 mmHg, HCO3- 28.50 mmHg, BE 3.133 mmol/l, O2SAT 93.375%, ctCO2 31.652 mmol/l), indicating compensated respiratory acidosis. The improvement of respiratory efficiency minimized acidosis symptoms in both venous blood (pH 7.365, pCO2 43.55 mmHg, pO2 47.80 mmHg, HCO3 30.325 mmHg, BE 3.050 mmol/l, O2SAT 80.10%, ctCO2 29.80 mmol/l) and arterial blood (pH 7.375, pCO2 39.268 mmHg, pO2 98.476 mmHg, HCO3- 26.651 mmHg, BE 4.956 mmol/l, O2SAT 98.475%, ctCO2 28.131 mmol/l). Venous blood parameters were marked by greater deviations from mean values, both before and after treatment. Acid-base indicators determined in venous blood are indicative of respiratory disturbances, but they do not support a comprehensive evaluation of gas exchange in the lungs.

  6. Estimated aortic blood pressure based on radial artery tonometry underestimates directly measured aortic blood pressure in patients with advancing chronic kidney disease staging and increasing arterial stiffness

    DEFF Research Database (Denmark)

    Carlsen, Rasmus K; Peters, Christian D; Khatir, Dinah S;

    2016-01-01

    we compared invasive aortic systolic BP (SBP) with estimated central SBP obtained by radial artery tonometry and examined the influence of renal function and arterial stiffness on this relationship. We evaluated 83 patients with stage 3 to 5 CKD (mean estimated glomerular filtration rate [eGFR] 30 ml......% confidence interval -14.9 to -11.4) mm Hg. Arterial stiffness was evaluated by carotid-femoral pulse wave velocity (cf-PWV) and was significantly increased in CKD patients compared with (versus) control patients (mean 10.7 vs. 9.3 m/s). The difference in BP significantly increased 1.0 mm Hg for every 10 ml....../min decrease in eGFR and by 1.6 mm Hg per 1 m/s increase in cfPWV. Using multivariate regression analysis including both eGFR and cfPWV, the difference between estimated central and invasive aortic SBP was significantly increased by 0.7 mm Hg. For the entire cohort brachial SBP significantly better reflected...

  7. Ambulatory instrument for monitoring indirect beat-to-beat blood pressure in superficial temporal artery using volume-compensation method.

    Science.gov (United States)

    Tanaka, S; Yamakoshi, K

    1996-11-01

    A portable instrument, based on a volume-compensation technique, is designed for ambulatory monitoring of indirect beat-to-beat blood pressure (BP) in the superficial temporal artery. The instrument consists of a small disc-type cuff and a portable unit carried by the subject. Several components are integrated in the cuff for applying counter-pressure to the artery, i.e. a reflectance-type photo-plethysmographic sensor for arterial volume detection, a pressure sensor for cuff pressure Pc measurement and a nozzle flapper-type- electro-pneumatic convertor for controlling Pc. The portable unit includes volume servo control circuitry and a microprocessor-based signal-processing and recording unit. This automatically performs all the necessary measurement procedures and stores into a memory IC element the processed systolic, mean and diastolic blood pressure data, together with pulse intervals on a beat-to-beat basis from the servo-controlled Pc (indirectly measured BP waveform). With this instrument, momentary changes in BP during ambulatory situations such as bicycle ergometer exercise and daily activities including motorway driving are successfully recorded. From the results of simultaneous measurement of the subject's posture changes, the effect of posture change on blood pressure, e.g. baroreceptor-cardiac reflex, is also clearly demonstrated.

  8. A RETROSPECTIVE STUDY OF THE IMPACT OF MEAN ARTERIAL PRESSURE ON ESTIMATED BLOOD LOSS DURING ENDOSCOPIC SINUS SURGERY

    Directory of Open Access Journals (Sweden)

    George W Williams

    2014-10-01

    Full Text Available The current practice of lowering mean arterial pressure (MAP during endoscopic sinus surgery (ESS is common, but unproven with regard to peer reviewed literature. The controlled hypotension induced is aimed for improved surgical field and lower the blood loss. Lower mean arterial pressures especially for prolonged surgeries may result in end organ hypoperfusion. The authors reviewed all patients who underwent outpatient endoscopic sinus surgery for the diagnosis of chronic sinusitis from January 1, 2012 to December 31, 2012 at Memorial Hermann Hospital – Texas Medical Centre. We individually reviewed case sheets of every patient and documented blood loss as recorded on the anaesthesia record or in the surgical procedure note, among other variables. A total of 326 patients were included in this study. The median estimated blood loss (EBL was found to be 50 ml. The multivariate regression analysis between these three groups showed that EBL was higher in MAP 75 group. The average of EBL in MAP75 group and the average of EBL in MAP 65-70 group is 42% higher than that in MAP>75 group when other variables were fixed. Hence we found the trend toward higher blood loss with lower MAP. The authors conclude that lower MAP does not result in lower EBL in endoscopic sinus surgery. Furthermore, increases in BMI and crystalloid administered during an aesthetic management of these cases correlates with increased estimate blood loss.

  9. Levels of vitamin C In the blood plasma patients treated with coronary artery bypass grafting increases significantly after surgery.

    Science.gov (United States)

    Kleszczewski, Tomasz; Modzelewska, Beata; Lisowska, Anna; Buzun, Leszek; Kleszczewska, Ewa

    2017-01-01

    One strong risk factor of coronary artery disease (CAD), which affects the levels of vitamin C in the blood is cigarette smoking. The supplementary effects of coronary artery bypass grafting (CABG) is smoking cessation by patients. Therefore, the aim of this study was to examine the level of vitamin C in the blood plasma one day before and one month after CABG. Human blood were collected from 20 patients (men); 1day before and 1 month after CABG. All patients were smoker and after CABG they declared their not smoking. The concentration of vitamin C in the blood plasma was assayed by FIA method with spectrophotometric detection. The mean value of the vitamin C concentration 1day before CABG was 12.36±2.84μmol/L (mean±SD), 1 month after CABG 40.07±10.95μmol/L (mean±SD). The average increase in the concentration of vitamin C was 3.27±0.73 times (mean±SD) and showed significant positive correlations (Pearson r=0.657, p=0.002). It should be consider incorporating the recommendations of preoperative smoking cessation for at least one month prior to CABG and/or additional supplementation. In addition it would be relevant to monitor the level of vitamin C in the patients' blood in the preoperative period.

  10. Comparison of cerebral blood flow measurement with [15O]-water positron emission tomography and arterial spin labeling magnetic resonance imaging: A systematic review.

    Science.gov (United States)

    Fan, Audrey P; Jahanian, Hesamoddin; Holdsworth, Samantha J; Zaharchuk, Greg

    2016-05-01

    Noninvasive imaging of cerebral blood flow provides critical information to understand normal brain physiology as well as to identify and manage patients with neurological disorders. To date, the reference standard for cerebral blood flow measurements is considered to be positron emission tomography using injection of the [(15)O]-water radiotracer. Although [(15)O]-water has been used to study brain perfusion under normal and pathological conditions, it is not widely used in clinical settings due to the need for an on-site cyclotron, the invasive nature of arterial blood sampling, and experimental complexity. As an alternative, arterial spin labeling is a promising magnetic resonance imaging technique that magnetically labels arterial blood as it flows into the brain to map cerebral blood flow. As arterial spin labeling becomes more widely adopted in research and clinical settings, efforts have sought to standardize the method and validate its cerebral blood flow values against positron emission tomography-based cerebral blood flow measurements. The purpose of this work is to critically review studies that performed both [(15)O]-water positron emission tomography and arterial spin labeling to measure brain perfusion, with the aim of better understanding the accuracy and reproducibility of arterial spin labeling relative to the positron emission tomography reference standard.

  11. Parallel artificial membrane permeability assay for blood-brain permeability determination of illicit drugs and synthetic analogues.

    Science.gov (United States)

    Clemons, Kristina; Kretsch, Amanda; Verbeck, Guido

    2014-09-01

    With the number of designer drugs on the streets rampantly on the rise, it's becoming more and more important to be able to rapidly characterize them in a biologically relevant way. Using a parallel artificial membrane permeability assay (PAMPA) to assess the blood brain barrier permeability has shown to be a high throughput way to compare new drugs with currently controlled substances via their effective permeability values. This combined with direct infusion electrospray ionization-mass spectrometry creates a rapid technique for characterization of new designer drugs. PAMPA has successfully determined the effective permeabilities of cocaine, methamphetamine, heroin, MDMA, and several tryptamine derivatives.

  12. Beneficial effects of prolonged blood pressure control after carotid artery stenting

    Directory of Open Access Journals (Sweden)

    Chang A

    2017-01-01

    Full Text Available Anna Chang,1 Huei-Fong Hung,2 Fang-I Hsieh,3 Wei-Hung Chen,1,4 Hsu-Ling Yeh,1,5 Jiann-Horng Yeh,1,6 Hou-Chang Chiu,1,6 Li-Ming Lien1,4 1Department of Neurology, Shin Kong Wu Ho-Su Memorial Hospital, Taipei, 2Department of Cardiology, Shin Kong Wu Ho-Su Memorial Hospital, Taipei, 3School of Public Health, College of Public Health, Taipei Medical University, Taipei, 4School of Medicine, College of Medicine, Taipei Medical University, Taipei, 5Institute of Public Health, National Yang-Ming University, Taipei, 6School of Medicine, College of Medicine, Fu Jen Catholic University, Taipei, Taiwan Objectives: The main purpose of this study was to investigate whether carotid artery stenting (CAS plus medicine in patients with severe carotid artery stenosis provide a better long-term blood pressure (BP control compared to other medical treatments alone. The other aim was to explore the correlation between post-CAS hypotension within 6 h and long-term BP reductions after CAS. Materials and methods: Patients with severe carotid stenosis were recruited either in the CAS group or in the medication group. BPs and the number of classes of antihypertensive agents were recorded at baseline, 6, and 12 months. Extra BP information was collected at 6 h, 3 days, and 1 month after CAS. Univariate and multivariate linear regressions were performed to test the relationship of BP changes among CAS and medication groups after 6 and 12 months of follow-up. Univariate linear regressions were also used to determine the correlations between the mean or maximal systolic BP (SBP reductions at 6 h and 1 year post-CAS. Results: In total, 72 members in the CAS group and 82 members in the medication group were recruited. Compared with the medication group, patients in the CAS group had greater BP reductions at 6 and 12 months of follow-up after adjusting for confounding factors (13.56 mmHg at 6 months, P=0.0002; 16.98 mmHg at 12 months, P<0.0001. This study also shows significant

  13. A comparison of two methods for calculating CR (time constant) during studies of arterial blood flow in rats.

    Science.gov (United States)

    Sasaoka, K; Ogawa, K

    1990-11-01

    Some of our earlier reports have dealt with experiments on the central caudal arteries of a series of anesthetized rats. The results of these experiments were expressed by a relationship derived from the Windkessel theory where f(t) = alpha dz(t)/dt + beta z(t). When this theory is used, the measured blood flow forms f(t) and calculated wave forms alpha dz(t)/dt + beta z(t) agree closely. In these studies, we discovered that, when blood flow adz(t)/dt + beta z(t) agree closely. In these studies, we discovered that, when blood flow decreases, CR (time constant tau, the product of the blood vessel compliance C and the peripheral resistance R) values increase and vary widely. In the present study, 1) we investigated changes in CR when blood flow increases, and, 2) the method of least squares was used in calculating the formula given above. We achieved a better conformity between measured blood flow and calculated blood flow and perceived a clearer relationship between mean blood flow and CR than when they were calculated by the old method.

  14. Hybrid procedure combining clip on wrapping and stent placement for ruptured supraclinoid blood blister-like aneurysm of the internal carotid artery.

    Science.gov (United States)

    Nagasaki, Hirokazu; Narikiyo, Michihisa; Nagayama, Gota; Nagao, Seiya; Tsuboi, Yoshifumi; Kambayashi, Chisaku

    2017-03-01

    Blood blister-like aneurysms of the supraclinoid portion of the internal carotid artery are rare, fragile, and thin-walled lesions with a higher rate of rebleeding. Our case underwent a hybrid procedure combining direct surgical and endovascular approach.

  15. Pseudo-asymmetry of cerebral blood flow in arterial spin labeling caused by unilateral fetal-type circle of Willis: Technical limitation or a way to better understanding physiological variations of cerebral perfusion and improving arterial spin labeling acquisition?

    Science.gov (United States)

    Law-Ye, B; Geerts, B; Galanaud, D; Dormont, D; Pyatigorskaya, N

    2016-09-01

    In the recently published article, "Unilateral fetal-type circle of Willis anatomy causes right-left asymmetry in cerebral blood flow with pseudo-continuous arterial spin labeling: A limitation of arterial spin labeling-based cerebral blood flow measurements?", it was shown by the method of arterial spin labeling (ASL) that unilateral fetal-type circle of Willis could induce variation of blood flow in cerebellar and posterior cerebral artery territory. We believe that the reported observation, rather than being a limitation, gives several interesting cues for understanding the ASL sequence. In this commentary, we formulate some suggestions regarding the use of ASL in clinical practice, discuss the potential causes of the above-mentioned pseudo-asymmetry and consider future improvements of the ASL technique.

  16. Hepatocellular Carcinoma with Blood Supply from Parasitized Omental Artery: Angiographic Appearance And Chemoembolization

    Institute of Scientific and Technical Information of China (English)

    Song Gao; Ren-jie Yang; Jia-hong Dong

    2012-01-01

    Objective:To analyze angiographic appearance of hepatocellular carcinoma (HCC) with blood supply from parasitized omental artery (POA),and evaluate the technical feasibility,safety and therapeutic efficacy of chemoembolization via the POAs.Methods:A total of 1,221 HCC patients who had undergone chemoembolization procedures were evaluated retrospectively.The evaluated indexes included the incidence rate of POAs,success rate of superselective catheterization,post-reaction after chemoembolization,and the cumulative survival rates.Results:Totally 1,221 HCC patients had undergone 3,639 chemoembolization procedures,and 32 patients with POAs were enrolled,with 97 POAs found in 76 angiography procedures,giving an incidence rate of 2.09%.POA was observed mostly at the right lobe and left medial lobe except the segment Ⅱ,and 62 POAs underwent superselective catheterization with microcatheter,giving a success rate of 63.9%.The angiographic appearance was:(1) hypertrophic POAs participating in tumor staining (n=28); (2) stiff and distorted POA (n=11),displaced due to tumor's oppression (n=8); and (3) defective tumor staining close to either gastrocolic omentum distribution or liver capsule (n=7).In 19 patients,chemoembolization via POAs was performed successfully (A group),while the remaining 13 patients failed (B group).Except 1 acute edema pancreatitis case,no serious complication was recorded.The cumulative survival rates of 6-,12-,18-and 24-month were 78.9%,47.4%,31.6% and 21.1% respectively for A group; correspondingly,61.5%,30.g%,15.4% and 7.7%% for B group,in which 2 patients died of ruptured HCC.Conclusion:Chemoembolization with microcatheter via POAs is a relatively safe,feasible and valuable method.

  17. Prognostic value of blood flow measurements using arterial spin labeling in gliomas.

    Directory of Open Access Journals (Sweden)

    Julia Furtner

    Full Text Available The period of event-free survival (EFS within the same histopathological glioma grades may have high variability, mainly without a known cause. The purpose of this study was to reveal the prognostic value of quantified tumor blood flow (TBF values obtained by arterial spin labeling (ASL for EFS in patients with histopathologically proven astrocytomas independent of WHO (World Health Organization grade. Twenty-four patients with untreated gliomas underwent tumor perfusion quantification by means of pulsed ASL in 3T. The clinical history of the patients was retrospectively extracted from the local database. Six patients had to be excluded due to insufficent follow-up data for further evaluation or histopathologically verified oligodendroglioma tumor components. Receiver operating characteristic (ROC curves were used to define an optimal cut-off value of maximum TBF (mTBF values for subgrouping in low-perfused and high-perfused gliomas. Kaplan-Meier curves and Cox proportional hazard regression model were used to determine the prognostic value of mTBF for EFS. An optimal mTBF cut-off value of 182 ml/100 g/min (sensitivity  = 83%, specificity  = 100% was determined. Patients with low-perfused gliomas had significantly longer EFS compared to patients with high-perfused gliomas (p = 0.0012 independent of the WHO glioma grade. Quantified mTBF values obtained by ASL offer a new and totally non-invasive marker to prognosticate the EFS, independently on histopathological tumor grading, in patients with gliomas.

  18. Cerebral blood flow volume measurements of the carotid artery and ipsilateral branches using two-dimensional phase-contrast magnetic resonance angiography

    Institute of Scientific and Technical Information of China (English)

    Gang Guo; Yonggui Yang; Weiqun Yang

    2011-01-01

    The optimal velocity encoding of phase-contrast magnetic resonance angiography (PC MRA) in measuring cerebral blood flow volume (BFV) ranges from 60 to 80 cm/s. To verify the accuracy of two-dimensional (2D) PC MRA, the present study localized the region of interest at blood vessels of the neck using PC MRA based on three-dimensional time-of-flight sequences, and the velocity encodingwas set to 80 cm/s. Results of the measurements showed that the error rate was 7.0 ± 6.0%in the estimation of BFV in the internal carotid artery, the external carotid artery and the ipsilateralcommon carotid artery. There was no significant difference, and a significant correlation in BFV between internal carotid artery + external carotid artery and ipsilateral common carotid artery. Inaddition, the BFV of the common carotid artery was correlated with that of the ipsilateral internal carotid artery. The main error was attributed to the external carotid artery and its branches. Therefore,after selecting the appropriate scanning parameters and protocols, 2D PC MRA is more accuratein the determination of BFV in the carotid arteries.

  19. Hemodynamic analysis in an idealized artery tree: differences in wall shear stress between Newtonian and non-Newtonian blood models.

    Directory of Open Access Journals (Sweden)

    Jared C Weddell

    Full Text Available Development of many conditions and disorders, such as atherosclerosis and stroke, are dependent upon hemodynamic forces. To accurately predict and prevent these conditions and disorders hemodynamic forces must be properly mapped. Here we compare a shear-rate dependent fluid (SDF constitutive model, based on the works by Yasuda et al in 1981, against a Newtonian model of blood. We verify our stabilized finite element numerical method with the benchmark lid-driven cavity flow problem. Numerical simulations show that the Newtonian model gives similar velocity profiles in the 2-dimensional cavity given different height and width dimensions, given the same Reynolds number. Conversely, the SDF model gave dissimilar velocity profiles, differing from the Newtonian velocity profiles by up to 25% in velocity magnitudes. This difference can affect estimation in platelet distribution within blood vessels or magnetic nanoparticle delivery. Wall shear stress (WSS is an important quantity involved in vascular remodeling through integrin and adhesion molecule mechanotransduction. The SDF model gave a 7.3-fold greater WSS than the Newtonian model at the top of the 3-dimensional cavity. The SDF model gave a 37.7-fold greater WSS than the Newtonian model at artery walls located immediately after bifurcations in the idealized femoral artery tree. The pressure drop across arteries reveals arterial sections highly resistive to flow which correlates with stenosis formation. Numerical simulations give the pressure drop across the idealized femoral artery tree with the SDF model which is approximately 2.3-fold higher than with the Newtonian model. In atherosclerotic lesion models, the SDF model gives over 1 Pa higher WSS than the Newtonian model, a difference correlated with over twice as many adherent monocytes to endothelial cells from the Newtonian model compared to the SDF model.

  20. Hemodynamic analysis in an idealized artery tree: differences in wall shear stress between Newtonian and non-Newtonian blood models.

    Science.gov (United States)

    Weddell, Jared C; Kwack, JaeHyuk; Imoukhuede, P I; Masud, Arif

    2015-01-01

    Development of many conditions and disorders, such as atherosclerosis and stroke, are dependent upon hemodynamic forces. To accurately predict and prevent these conditions and disorders hemodynamic forces must be properly mapped. Here we compare a shear-rate dependent fluid (SDF) constitutive model, based on the works by Yasuda et al in 1981, against a Newtonian model of blood. We verify our stabilized finite element numerical method with the benchmark lid-driven cavity flow problem. Numerical simulations show that the Newtonian model gives similar velocity profiles in the 2-dimensional cavity given different height and width dimensions, given the same Reynolds number. Conversely, the SDF model gave dissimilar velocity profiles, differing from the Newtonian velocity profiles by up to 25% in velocity magnitudes. This difference can affect estimation in platelet distribution within blood vessels or magnetic nanoparticle delivery. Wall shear stress (WSS) is an important quantity involved in vascular remodeling through integrin and adhesion molecule mechanotransduction. The SDF model gave a 7.3-fold greater WSS than the Newtonian model at the top of the 3-dimensional cavity. The SDF model gave a 37.7-fold greater WSS than the Newtonian model at artery walls located immediately after bifurcations in the idealized femoral artery tree. The pressure drop across arteries reveals arterial sections highly resistive to flow which correlates with stenosis formation. Numerical simulations give the pressure drop across the idealized femoral artery tree with the SDF model which is approximately 2.3-fold higher than with the Newtonian model. In atherosclerotic lesion models, the SDF model gives over 1 Pa higher WSS than the Newtonian model, a difference correlated with over twice as many adherent monocytes to endothelial cells from the Newtonian model compared to the SDF model.

  1. Biological artificial vessel graft in distal arterial bypass for treating diabetic lower limb ischemia: a case report

    Institute of Scientific and Technical Information of China (English)

    GU Yong-quan; WU Ying-feng; QI Li-xing; GUO Lian-ri; LI Xue-feng; CUI Shi-jun; TONG Zhu; GUO Jian-ming; ZHANG Jian

    2011-01-01

    A 68-year-old female patient was treated for unhealed ulcer in the fourth toe of the left foot. Clinical examinations identified severe stenosis of the proximal segment and occlusion of the distal segment of the left anterior tibial artery, and occlusion of the left posterior tibial artery and the peroneal artery. The proximal stenotic segment of the left anterior tibial artery was dilated, but the distal occlusive part failed to be re-canalized. Left anterior tibial artery to dorsal pedal artery bypass was performed on the patient with an epoxide-crosslinked, special radicals antigen-sealed, porcine-derived biological graft; debridement of the left 4th digiti pedis was also performed. Postoperation course was uneventful. The pulse of the left dorsal pedal artery was strong. The ankle brachial index (ABI) increased from 0.60 to 1.09. Warfarin and two antiplatelet drugs were given after the operation. Six months after operation, computed tomographic angiogram (CTA)identified the patent graft.

  2. The in vitro effects of artificial and natural sweeteners on the immune system using whole blood culture assays.

    Science.gov (United States)

    Rahiman, F; Pool, E J

    2014-01-01

    This article investigates the effects of commercially available artificial (aspartame, saccharin, sucralose) and natural sweeteners (brown sugar, white sugar, molasses) on the immune system. Human whole blood cultures were incubated with various sweeteners and stimulated in vitro with either phytohemagglutinin or endotoxin. Harvested supernatants were screened for cytotoxicity and cytokine release. Results showed that none of the artificial or natural sweeteners proved to be cytotoxic, indicating that no cell death was induced in vitro. The natural sweetener, sugar cane molasses (10 ug/mL), enhanced levels of the inflammatory biomarker IL-6 while all artificial sweeteners (10 ug/mL) revealed a suppressive effect on IL-6 secretion (P sweeteners under stimulatory conditions reduced levels of the biomarker of humoral immunity, Interleukin-10 (P < 0.001). The cumulative suppression of Interleukin-6 and Interleukin-10 levels induced by sucralose may contribute to the inability in mounting an effective humoral response when posed with an exogenous threat.

  3. Combining Personality Traits with Traditional Risk Factors for Coronary Stenosis: An Artificial Neural Networks Solution in Patients with Computed Tomography Detected Coronary Artery Disease

    Directory of Open Access Journals (Sweden)

    Angelo Compare

    2013-01-01

    Full Text Available Background. Coronary artery disease (CAD is a complex, multifactorial disease in which personality seems to play a role but with no definition in combination with other risk factors. Objective. To explore the nonlinear and simultaneous pathways between traditional and personality traits risk factors and coronary stenosis by Artificial Neural Networks (ANN data mining analysis. Method. Seventy-five subjects were examined for traditional cardiac risk factors and personality traits. Analyses were based on a new data mining method using a particular artificial adaptive system, the autocontractive map (AutoCM. Results. Several traditional Cardiovascular Risk Factors (CRF present significant relations with coronary artery plaque (CAP presence or severity. Moreover, anger turns out to be the main factor of personality for CAP in connection with numbers of traditional risk factors. Hidden connection map showed that anger, hostility, and the Type D personality subscale social inhibition are the core factors related to the traditional cardiovascular risk factors (CRF specifically by hypertension. Discussion. This study shows a nonlinear and simultaneous pathway between traditional risk factors and personality traits associated with coronary stenosis in CAD patients without history of cardiovascular disease. In particular, anger seems to be the main personality factor for CAP in addition to traditional risk factors.

  4. Integration of Quantitative Positron Emission Tomography Absolute Myocardial Blood Flow Measurements in the Clinical Management of Coronary Artery Disease.

    Science.gov (United States)

    Gewirtz, Henry; Dilsizian, Vasken

    2016-05-31

    In the >40 years since planar myocardial imaging with(43)K-potassium was introduced into clinical research and management of patients with coronary artery disease (CAD), diagnosis and treatment have undergone profound scientific and technological changes. One such innovation is the current state-of-the-art hardware and software for positron emission tomography myocardial perfusion imaging, which has advanced it from a strictly research-oriented modality to a clinically valuable tool. This review traces the evolving role of quantitative positron emission tomography measurements of myocardial blood flow in the evaluation and management of patients with CAD. It presents methodology, currently or soon to be available, that offers a paradigm shift in CAD management. Heretofore, radionuclide myocardial perfusion imaging has been primarily qualitative or at best semiquantitative in nature, assessing regional perfusion in relative terms. Thus, unlike so many facets of modern cardiovascular practice and CAD management, which depend, for example, on absolute values of key parameters such as arterial and left ventricular pressures, serum lipoprotein, and other biomarker levels, the absolute levels of rest and maximal myocardial blood flow have yet to be incorporated into routine clinical practice even in most positron emission tomography centers where the potential to do so exists. Accordingly, this review focuses on potential value added for improving clinical CAD practice by measuring the absolute level of rest and maximal myocardial blood flow. Physiological principles and imaging fundamentals necessary to understand how positron emission tomography makes robust, quantitative measurements of myocardial blood flow possible are highlighted.

  5. Evaluation of the Effects of Sildenafil Citrate (Viagra) on Vertebral Artery Blood Flow in Patients with Vertebro-Basilar Insufficiency

    Energy Technology Data Exchange (ETDEWEB)

    Bozgeyik, Zulkif; Berilgen, Sait; Ozdemir, Huseyin; Ogur, Erkin [Firat University School of Medicine, Elazig(Turkmenistan); Tekatas, Aslan [Elazig Government Hospital, Elazig (Turkmenistan)

    2008-12-15

    To investigate the effects of sildenafil citrate (Viagra) on the vertebral artery blood flow of patients with vertebro-basilar insufficiency (VBI) using color duplex sonography (CDS). The study included 21 patients with VBI (aged 31-76; mean 61.0 +- 10.5 yrs). We administered a 50 mg oral dose of sildenafil citrate to all patients. Next, we measured the peak systolic velocity (Vmax), end diastolic velocity (Vmin), resistive index (RI), pulsatility index (PI), diameter, area, and flow volume (FV) of vertebral arteries using CDS before the administration of sildenafil citrate; 45 minutes after, and 75 minutes after administration. Statistical testing was performed using SPSS for windows version 11.0. The statistical test used to determine the outcome of the analysis was the repeated measures analysis of variance (ANOVA) test. Compared to the baseline values, the vertebral artery diameter, area, and FV increased significantly following the administration of sildenafil citrate. The diameter, area and FV increased from 3.39 mm at 45 minutes to 3.64 mm at 75 minutes, 9.43 cm{sup 2} to 10.80 cm{sup 2} at 45 minutes and 10.81 cm{sup 2} at 75 minutes, as well as from 0.07 L/min at baseline to 0.09 L/min at 45 minutes and unchanged at 75 minutes, respectively. Sildenafil citrate elicited a significant effect on vertebral artery diameter, area and FVs

  6. Suspension model for blood flow through a catheterized arterial stenosis with peripheral layer of plasma free from cells

    Science.gov (United States)

    Ponalagusamy, R.

    2016-06-01

    The present article describes the blood flow in a catheterized artery with radially symmetric and axially asymmetric stenosis. To understand the effects of red cell concentration, plasma layer thickness and catheter size simultaneously, blood is considered by a two-layered model comprising a core region of suspension of all the erythrocytes (particles) supposed to be a particle-fluid mixture and a peripheral zone of cell-free plasma. The analytical expressions for flow features, such as fluid phase and particle phase velocities, flow rate, wall shear stress and resistive force are obtained. It is witnessed that the presence of the catheter causes a substantial increase in the frictional forces on the walls of arterial stenosis and catheter, shear stress and flow resistance, in addition to that, have occurred due to the presence of red cells concentration (volume fraction density of the particles) and the absence of peripheral plasma layer near the wall of the stenosed artery. The introduction of an axially asymmetric nature of stenosis and plasma layer thickness causes significant reduction in flow resistance. One can notice that the two-phase fluid (suspension model) is more profound to the thickness of peripheral plasma layer and catheter than the single-phase fluid.

  7. Modeling of the blood flow in the lower extremities for dynamic diffuse optical tomography of peripheral artery disease

    Science.gov (United States)

    Marone, A.; Hoi, J. W.; Khalil, M. A.; Kim, H. K.; Shrikhande, G.; Dayal, R.; Hielscher, A. H.

    2015-07-01

    Peripheral Arterial Disease (PAD) is caused by a reduction of the internal diameters of the arteries in the upper or lower extremities mainly due to atherosclerosis. If not treated, its worsening may led to a complete occlusion, causing the death of the cells lacking proper blood supply, followed by gangrene that may require chirurgical amputation. We have recently performed a clinical study in which good sensitivities and specificities were achieved with dynamic diffuse optical tomography. To gain a better understanding of the physiological foundations of many of the observed effects, we started to develop a mathematical model for PAD. The model presented in this work is based on a multi-compartment Windkessel model, where the vasculature in the leg and foot is represented by resistors and capacitors, the blood pressure with a voltage drop, and the blood flow with a current. Unlike existing models, the dynamics induced by a thigh-pressure-cuff inflation and deflation during the measurements are taken into consideration. This is achieved by dynamically varying the resistances of the large veins and arteries. By including the effects of the thigh-pressure cuff, we were able to explain many of the effects observed during our dynamic DOT measurements, including the hemodynamics of oxy- and deoxy-hemoglobin concentration changes. The model was implemented in MATLAB and the simulations were normalized and compared with the blood perfusion obtained from healthy, PAD and diabetic patients. Our preliminary results show that in unhealthy patients the total system resistance is sensibly higher than in healthy patients.

  8. MR angiography of collateral arteries in a hind limb ischemia model: comparison between blood pool agent Gadomer and small contrast agent Gd-DTPA.

    Directory of Open Access Journals (Sweden)

    Karolien Jaspers

    Full Text Available The objective of this study was to compare the blood pool agent Gadomer with a small contrast agent for the visualization of ultra-small, collateral arteries (diameter0.10. Inter-observer variation was 24% and 18% for Gadomer and Gd-DTPA, respectively. In conclusion, blood pool agent Gadomer improved vessel conspicuity compared to Gd-DTPA. Steady-state MRA can be considered as an excellent non-invasive alternative to intra-arterial XRA for the visualization of ultra-small collateral arteries.

  9. Blood flow parameters of the superior mesenteric artery as an early predictor of intestinal dysmotility in preterm infants

    Energy Technology Data Exchange (ETDEWEB)

    Robel-Tillig, Eva; Knuepfer, Matthias; Pulzer, Ferdinand; Vogtmann, Christoph [University of Leipzig, Department of Neonatology, Children' s Hospital, Leipzig (Germany)

    2004-12-01

    Blood flow parameters in the superior mesenteric artery (SMA) change with vasoconstriction or vasodilatation of the intestinal vascular bed. In cases of severe growth retardation as a result of haemodynamic disturbances, the blood flow changes persist into postnatal life. To assess early changes of Doppler sonographic blood flow parameters in the SMA for prediction of later intestinal motility disturbances in preterm infants and tolerance of enteral feeding during the first week of life. Doppler sonographic blood flow parameters in the SMA were measured on the first day of life and the following 5 days in 478 neonates with a birth weight below 1,500 g. According to the Doppler results, the neonates were divided into two groups - those with pathological parameters and those with normal blood flow parameters. Correlations between blood flow parameters, the development of intestinal dysmotility and the tolerated amount of enteral feeding were calculated. Pathological blood flow parameters were observed in 148 neonates (group 1) and normal blood flow parameters in 330 neonates (group 2). Intestinal motility disturbance occurred in 125 neonates (83%) of group 1 and 47 neonates (15%) of group 2. Neonates in group 2 tolerated significantly more feed by the fifth day of life than neonates in group 1. Postnatal adaptation did not differ between the two groups, although the majority of neonates with intestinal dysmotility were small for gestational age. The predictive value of blood flow parameters for prediction of intestinal motility revealed high sensitivity and specificity by the first postnatal day, 2 or 3 days before development of clinical signs of intestinal dysmotility. There was a strong negative correlation between pathological pulsatility index on day 1 and the quantity of tolerated enteral feeding on day 5. Pathological blood flow parameters in the SMA can predict problems of intestinal motility and tolerance of enteral feeding. With the early detection of these

  10. NUMERICAL ANALYSIS OF THE NON-NEWTONIAN BLOOD FLOW IN THE NON-PLANAR ARTERY WITH BIFURCATION

    Institute of Scientific and Technical Information of China (English)

    CHEN Jie; LU Xi-yun; ZHUANG Li-xian; WANG Wen

    2004-01-01

    A numerical analysis of non-Newtonian fluid flow in non-planar artery with bifurcation was performed by using a finite element method to solve the three-dimensional Navier-Stokes equations coupled with the non-Newtonian constitutive models, including Carreau,Cross and Bingham models. The objective of this study is to investigate the effects of the non-Newtonian properties of blood as well as curvature and out-of-plane geometry in the non-planar daughter vessels on the velocity distribution and wall shear stress. The results of this study support the view that the non-planarity of blood vessels and the non-Newtonian properties of blood are of important in hemodynamics and play a significant role in vascular biology and pathophysiology.

  11. Simulations of time harmonic blood flow in the Mesenteric artery: comparing finite element and lattice Boltzmann methods

    Directory of Open Access Journals (Sweden)

    Hose Rod

    2009-10-01

    Full Text Available Abstract Background Systolic blood flow has been simulated in the abdominal aorta and the superior mesenteric artery. The simulations were carried out using two different computational hemodynamic methods: the finite element method to solve the Navier Stokes equations and the lattice Boltzmann method. Results We have validated the lattice Boltzmann method for systolic flows by comparing the velocity and pressure profiles of simulated blood flow between methods. We have also analyzed flow-specific characteristics such as the formation of a vortex at curvatures and traces of flow. Conclusion The lattice Boltzmann Method is as accurate as a Navier Stokes solver for computing complex blood flows. As such it is a good alternative for computational hemodynamics, certainly in situation where coupling to other models is required.

  12. Inactivation of neuronal function in the amygdaloid region reduces tail artery blood flow alerting responses in conscious rats.

    Science.gov (United States)

    Mohammed, M; Kulasekara, K; De Menezes, R C; Ootsuka, Y; Blessing, W W

    2013-01-03

    Few studies have investigated whether neuronal function in the amygdaloid complex is necessary for the occurrence of the cardiovascular response to natural (unconditioned) environmental threats. In the present investigation in conscious unrestrained Sprague-Dawley rats we inactivated neuronal function in the amygdaloid complex acutely (bilateral muscimol injections) or chronically (unilateral or bilateral ibotenic acid injections) and measured the effect on sudden falls in tail artery blood flow elicited by non-noxious salient stimuli (sympathetic cutaneous vasomotor alerting responses, SCVARs). After acute bilateral injection of vehicle (200nl Ringer's solution) the SCVAR index was 81 ± 2%, indicating that tail blood flow was reduced by 81% in response to the salient stimuli. After acute bilateral injection of muscimol (1 nmol in 200 nl of Ringer's solution) into the amygdaloid complex the SCVAR index was 49 ± 5%, indicating that tail blood flow was reduced by 49% in response to the salient stimuli (pbody with more immediate metabolic requirements.

  13. Evaluation of adjusted central venous blood gases versus arterial blood gases of patients in post-operative paediatric cardiac surgical intensive care unit

    Directory of Open Access Journals (Sweden)

    Naveen G Singh

    2015-01-01

    Full Text Available Background and Aims: Central venous catheters are in situ in most of the intensive care unit (ICU patients, which may be an alternative for determining acid-base status and can reduce complications from prolonged arterial cannulation. The aim of this study was to examine the reliability between adjusted central venous blood gas (aVBG and arterial blood gas (ABG samples for pH, partial pressure of carbon-di-oxide (pCO2, bicarbonate (HCO3−, base excess (BE and lactates in paediatric cardiac surgical ICU. Methods: We applied blood gas adjustment rule, that is aVBG pH = venous blood gas (VBG pH +0.05, aVBG CO2 = VBG pCO2 - 5 mm Hg from the prior studies. In this study, we validated this relationship with simultaneous arterial and central venous blood obtained from 30 patients with four blood sample pairs each in paediatric cardiac surgical ICU patients. Results: There was a strong correlation (R i.e., Pearson's correlation between ABG and aVBG for pH = 0.9544, pCO2 = 0.8738, lactate = 0.9741, HCO3− = 0.9650 and BE = 0.9778. Intraclass correlation co-efficients (ICCs for agreement improved after applying the adjustment rule to venous pH (0.7505 to 0.9454 and pCO2 (0.4354 to 0.741. Bland Altman showed bias (and limits of agreement for pH: 0.008 (−0.04 to + 0.057, pCO2: −3.52 (–9.68 to +2.65, lactate: −0.10 (−0.51 to +0.30, HCO3−: −2.3 (–5.11 to +0.50 and BE: −0.80 (−3.09 to +1.49. Conclusion: ABG and aVBG samples showed strong correlation, acceptable mean differences and improved agreement (high ICC after adjusting the VBG. Hence, it can be promising to use trend values of VBG instead of ABG in conjunction with a correction factor under stable haemodynamic conditions.

  14. Mathematical Analysis of Casson Fluid Model for Blood Rheology in Stenosed Narrow Arteries

    Directory of Open Access Journals (Sweden)

    J. Venkatesan

    2013-01-01

    stress, as obtained by Misra and Shit (2006. It is also noticed that the resistance to flow and skin friction increase (when normalized with Newtonian fluid in stenosed artery with the increase of the yield stress.

  15. Correlation between 24-hour profile of blood pressure and ventricular arrhythmias and their prognostic significance in patients with arterial hypertension

    Directory of Open Access Journals (Sweden)

    Đorđević Dragan

    2008-01-01

    Full Text Available Background/Aim. Left ventricular hypertrophy (LVH, apart from arterial hypertension, is a risk factor for electrophysiologic heart condition disorder and sudden cardiac death. The aim of this study was to examine a relationship between complex ventricular arrhythmias and parameters of 24-hour ambulatory blood pressure monitoring in the patients with arterial hypertension and left ventricular hypertrophy (LVH, as well as their prognostic significance during a five-year follow-up. Methods. Ninety patients with arterial hypertension and LVH were included in this study (mean age 55.2±8.3 years. There were 35 healthy people in the control group (mean age 54.5±7.1 years. Left ventricular mass index was 171.9±32.4 g/m2 in the LVH group and 102.4±13.3 g/m2 in the control group. Clinical examination, echocardiogram, 24-hour ambulatory blood pressure monitoring and 24-hour holter monitoring were done in all of the examined persons. Ventricular arrhythmias were classified by the Lown classification. Results. In the LVH group there were 54 (60.0% of the patients with ≥ III Lown class. The best predictor of a Lown class were left ventricular mass index by using multivariate stepwise regression analyses (β = 0.212; p < 0.05 and small decrease of diastolic blood pressure during the night (β = -0.293; p < 0.01. The main predictor of bad prognosis was left ventricular mass index during a five year follow-up (β = 0.302; p < 0.01, for stepwise regression model: F = 8.828; p < 0.01, adjusted R2 = 0.091. Conclusion. Left ventricular arrhythmias are frequent in patients with lower decrease of blood pressure during the night. There was no correlation between the degree of ventricular arrhythmias and parameters from 24-hour blood pressure monitoring and a five-year prognosis in the patients with arterial hypertension and LVH. A bad five-year follow-up outcome of hypertensive disease depends on left ventricular mass index.

  16. Outflow boundary conditions for 3D simulations of non-periodic blood flow and pressure fields in deformable arteries

    CERN Document Server

    Vignon-Clementel, Irene; Jansen, K E; Taylor, C A; 10.1080/10255840903413565

    2010-01-01

    The simulation of blood flow and pressure in arteries requires outflow boundary conditions that incorporate models of downstream domains. We previously described a coupled multidomain method to couple analytical models of the downstream domains with 3D numerical models of the upstream vasculature. This prior work either included pure resistance boundary conditions or impedance boundary conditions based on assumed periodicity of the solution. However, flow and pressure in arteries are not necessarily periodic in time due to heart rate variability, respiration, complex transitional flow or acute physiological changes. We present herein an approach for prescribing lumped parameter outflow boundary conditions that accommodate transient phenomena. We have applied this method to compute haemodynamic quantities in different physiologically relevant cardiovascular models, including patient-specific examples, to study non-periodic flow phenomena often observed in normal subjects and in patients with acquired or congen...

  17. The giraffe kidney tolerates high arterial blood pressure by high renal interstitial pressure and low glomerular filtration rate

    DEFF Research Database (Denmark)

    Damkjær, Mads; Wang, T; Brøndum, E

    2015-01-01

    BACKGROUND: The tallest animal on earth, the giraffe (Giraffa camelopardalis) is endowed with a mean arterial blood pressure (MAP) twice that of other mammals. The kidneys reside at heart level and show no sign of hypertension-related damage. We hypothesized that a species-specific evolutionary...... on body mass. A strong renal capsule supports a RIHP, which is >10-fold that of other mammals effectively reducing the net filtration pressure and protecting against the high MAP....... renal plasma flow (ERPF). Renal interstitial hydrostatic pressure (RIHP) was assessed by inserting a needle into the medullary parenchyma. Doppler ultrasound measurements provided renal artery resistive index (RI). Hormone concentrations as well as biomechanical, structural and histological...

  18. Theoretical Analysis of Shear Thinning Hyperbolic Tangent Fluid Model for Blood Flow in Curved Artery with Stenosis

    Directory of Open Access Journals (Sweden)

    Sohail Nadeem

    2016-01-01

    Full Text Available In this paper, we have considered the blood flow in a curved channel with abnormal development of stenosis in an axis-symmetric manner. The constitutive equations for incompressible and steady non-Newtonian tangent hyperbolic fluid have been modeled under the mild stenosis case. A perturbation technique and homotopy perturbation technique have been used to obtain analytical solutions for the wall shear stress, resistance impedance to flow, wall shear stress at the stenosis throat and velocity profile. The obtained results have been discussed for different tapered arteries i.e., diverging tapering, converging tapering, non-tapered arteries with the help of different parameters of interest and found that tapering dominant the curvature of the curved channel.

  19. [Coronary artery blood flow velocity non-invasively measured using a vessel-tracking pulsed Doppler system].

    Science.gov (United States)

    Tateishi, O; Aizawa, O; Okamura, T; Yoshida, T; Furuhata, H; Seo, Y; Iinuma, K; Shiki, E

    1988-09-01

    A newly-developed noninvasive method was used to measure left coronary blood flow during phantom experiments. Two techniques were used in which: (1) the sample position can always be set in a fluctuating vessel using a wall echo-tracking method with a phase-locked-loop, and (2) the Doppler reference signal was generated separately synchronous with the wall echo signal. These techniques were combined, using a commercially available pulsed Doppler apparatus (SSH-40B: Toshiba). Basic experiments were performed using a blood vessel phantom to verify the validity of these systems. Blood flow velocity in the fluctuating tube could be measured clearly using a vessel-tracking method. The blood flow velocity of the left anterior descending artery was measured in three normal subjects and in seven patients from the third intercostal space along the left sternal border. The velocity pattern was characterized by a crescendo-decrescendo shape in diastole. The peak velocity which appeared in diastole ranged from 19 to 69 cm/sec, with no difference by disease entity. However, in all cases, the blood flow velocity signals were marred by extraneous signals, making it impossible to measure blood flow velocity during systole. Further improvement of the system is mandatory in order to use this flowmeter clinically.

  20. Changes in central retinal artery blood flow after ocular warming and cooling in healthy subjects

    Directory of Open Access Journals (Sweden)

    Shamshad M

    2010-01-01

    Full Text Available Context: Retinal perfusion variability impacts ocular disease and physiology. Aim: To evaluate the response of central retinal artery (CRA blood flow to temperature alterations in 20 healthy volunteers. Setting and Design: Non-interventional experimental human study. Materials and Methods: Baseline data recorded: Ocular surface temperature (OST in °C (thermo-anemometer, CRA peak systolic velocity (PSV and end diastolic velocity (EDV in cm/s using Color Doppler. Ocular laterality and temperature alteration (warming by electric lamp/cooling by ice-gel pack were randomly assigned. Primary outcomes recorded were: OST and intraocular pressure (IOP immediately after warming or cooling and ten minutes later; CRA-PSV and EDV at three, six and nine minutes warming or cooling. Statistical Analysis: Repeated measures ANOVA. Results: (n = 20; μ±SD: Pre-warming values were; OST: 34.5±1.02°C, CRA-PSV: 9.3±2.33cm/s, CRA-EDV: 4.6±1.27cm/s. OST significantly increased by 1.96°C (95% CI: 1.54 to 2.37 after warming, but returned to baseline ten minutes later. Only at three minutes, the PSV significantly rose by 1.21cm/s (95% CI: 0.51to1.91. Pre-cooling values were: OST: 34.5±0.96°C, CRA-PSV: 9.7±2.45 cm/s, CRA-EDV: 4.7±1.12cm/s. OST significantly decreased by 2.81°C (95% CI: -2.30 to -3.37 after cooling, and returned to baseline at ten minutes. There was a significant drop in CRA-PSV by 1.10cm/s (95% CI: -2.05 to -0.15 and CRA-EDV by 0.81 (95% CI: -1.47 to -0.14 at three minutes. At six minutes both PSV (95% CI: -1.38 to -0.03 and EDV (95% CI: -1.26 to -0.02 were significantly lower. All values at ten minutes were comparable to baseline. The IOP showed insignificant alteration on warming (95% CI of difference: -0.17 to 1.57mmHg, but was significantly lower after cooling (95% CI: -2.95 to -4.30mmHg. After ten minutes, IOP had returned to baseline. Conclusion : This study confirms that CRA flow significantly increases on warming and decreases on cooling

  1. Benidipine has effects similar to losartan on the central blood pressure and arterial stiffness in mild to moderate essential hypertension

    Institute of Scientific and Technical Information of China (English)

    Sang-Hyun Ihm; Hui-Kyung Jeon; Shung Chull Chae; Do-Sun Lim; Kee-Sik Kim; Dong-Ju Choi; Jong-Won Ha

    2013-01-01

    Background Central blood pressure (BP) is pathophysiologically more important than peripheral BP for the pathogenesis of cardiovascular disease.Arterial stiffness is also a good predictor of cardiovascular morbidity and mortality.The effects of benidipine,a unique dual L-/T-type calcium channel blocker,on central BP have not been reported.This study aimed to compare the effect of benidipine and losartan on the central BP and arterial stiffness in mild to moderate essential hypertensives.Methods This 24 weeks,multi-center,open label,randomized,active drug comparative,parallel group study was designed as a non-inferiority study.The eligible patients (n=200) were randomly assigned to receive benidipine (n=101)or losartan (n=99).Radial artery applanation tonometry and pulse wave analysis were used to measure the central BP,pulse wave velocity (PWV) and augmentation index (Alx).We also measured the metabolic and inflammatory markers.Results After 24 weeks,the central BP decreased significantly from baseline by (16.8+14.0/10.5+9.2) mmHg (1mmHg =0.133 kPa) (systolic/diastolic BP; P <0.001) in benidipine group and (18.9+14.7/12.1+10.2) mmHg (P <0.001)in losartan group respectively.Both benidipine and losartan groups significantly lowered peripheral BP (P <0.001) and Alx (P <0.05),but there were no significant differences between the two groups.The mean aortic,brachial and femoral PWV did not change in both groups after 24-week treatment.There were no significant changes of the blood metabolic and inflammatory biomarkers in each group.Conclusion Benidipine is as effective as losartan in lowering the central and peripheral BP,and improving arterial stiffness.

  2. Laser Doppler flowmeter study on regional cerebral blood flow in early stage after standard superficial temporal artery-middle cerebral artery bypass surgery for moyamoya disease

    Institute of Scientific and Technical Information of China (English)

    GESANG Dun-zhu; ZHANG Dong; ZHAO Ji-zong; WANG Shuo; ZHAO Yuan-li; WANG Rong; SUN Jian-jun; MENG Ze

    2009-01-01

    Background Standard superficial temporal artery-middle cerebral artery (STA-MCA) bypass surgery is an effective treatment for moyamoya disease, but recent evidence suggests that postoperative cerebral hyperperfusion can occur. In this study, the trendline of changes in regional cerebral blood flow (rCBF) after surgery were continually monitored near the site of anastomosis in order to investigate both the efficacy of the procedure for improving rCBF and the possible riskof hyperperfusion.Methods Standard STA-MCA bypass surgery was performed on 13 patients, rCBF was measured continually using laser Doppler flowmetry (LDF) until the 5th day after the operation with the LDF probe implanted adjacent to the area of the anastomosis. The trendline of rCBF changes postoperatively was recorded for the analysis performed using SPSS 13.0.Results The baseline LDF value of cortical rCBF was (84.68±14.39) perfusion unit (PU), which was linear relative to absolute perfusion volume before anastomosis and (88.90±11.26) PU immediately after anastomosis (P >0.05). The value changed significantly from before to after anastomosis (P 0.05).Conclusions STA-MCA anastomosis improves the cerebral blood supply significantly in the early stage after surgery,however, the risk of symptomatic hyperperfusion may exist, which may possibly occur on the 1st day and 5th day after surgery. A LDF is useful for postoperative monitoring for both the efficacy of bypass and possible risk of neurologic deterioration or bleeding from hyperperfusion.

  3. [PULMONARY COMPLICATIONS IN CHILDREN, OPERATED ON FOR INBORN HEART FAILURES IN THE ARTIFICIAL BLOOD CIRCULATION ENVIRONMENT].

    Science.gov (United States)

    Moshkivska, L V; Nastenko, E A; Golovenko, O S; Lazoryshynets, V V

    2015-11-01

    The risk factors of pulmonary complications occurrence were analyzed in children, operated on for inborn heart failures in atrificial blood circulation environment. Pulmonary complications rate and the risk factors of their occurrence were analyzed.

  4. Cardiorespiratory and blood gas alterations during laparoscopic surgery for intra-uterine artificial insemination in dogs.

    Science.gov (United States)

    Fukushima, Fabíola B; Malm, Christina; Andrade, Maria Elisa J; Oliveira, Humberto P; Melo, Eliane G; Caldeira, Fátima Maria C; Gheller, Valentim A; Palhares, Maristela S; Macedo, Sabrina P; Figueiredo, Mariana S; Silva, Marcos X

    2011-01-01

    Cardiorespiratory and blood gas alterations were evaluated in 6 healthy dogs that underwent a laparoscopic procedure using isoflurane anesthesia and carbon dioxide (CO(2)) pneumoperitoneum for 30 min. Heart rate, respiratory rate, body temperature, venous blood pH, partial pressure of CO(2) and oxygen, oxygen saturation, total carbon dioxide (TCO(2)) and bicarbonate were monitored. Significant alterations were hypercapnia, hypoventilation, and respiratory acidosis.

  5. [Controlling of artificial blood pumps after total heart replacement - an example of disregulation (author's transl)].

    Science.gov (United States)

    Hennig, E; Affeld, K; Kless, H; Mohnhaupt, A; Mohhaupt, R; Clevert, D; Keibach, H; Krautzberger, W; Kleine, H O; Weidemann, H; Bücherl, E S

    1976-12-01

    This is a report on the special regulation problem of the left blood pump after replacement of the natural heart by incorporated extracorporally driven blood pumps in an animal experiment. The consequence of the peripheral self-regulation on the transporting capacity of the bloodpumps considering the driving pressure and the systemic pressure losses has been investigated. Two possible controlling principles and the respective fields of application are discussed on the example of a lung oedema.

  6. Pulsatility Index of Blood Echogenicity of the Human Radial and Common Carotid Arteries: Relation with Age and Stroke

    Energy Technology Data Exchange (ETDEWEB)

    Bok, Tae Hoon; Kong, Qi; Nam, Kweon Ho; Choi, Jay Chol; Paeng, Dong Guk [Department of Ocean System Engineering, Jeju National University, Jeju (Korea, Republic of)

    2012-10-15

    In the present paper, the ultrasound blood images were measured at both the human radial artery(RA) and common carotid artery(CCA), depending on the age, and the pulsatility index of blood echogenicity(PIBE) was analyzed. In addition, the ultrasound blood images were measured at both RA and CCA of both the stroke patients and the control group, and PIBE was compared. PIBE of RA for the young group was similar with that for the old group (0.13{+-}0.21 and 0.16{+-}0.03). PIBE of CCA for the young group, however, was larger than that for the old group (0.70{+-}0.21 and 0.32{+-}0.01), and was more variable depending on the subject. Similarly, the fibrinogen concentrations of the patients (336{+-}61 and 340{+-}126 mg/dl) were more than that of the control group (264{+-}38 and 43 mg/dl), for both RA and CCA. The results indicate the possibility of the ultrasonic test on the correlation between erythrocyte aggregation and stroke, and it is expected that the in-vivo EA measurement would be clinically useful.

  7. Reduced peripheral arterial blood flow with preserved cardiac output during submaximal bicycle exercise in elderly heart failure

    Directory of Open Access Journals (Sweden)

    Leng Xiaoyan

    2009-11-01

    Full Text Available Abstract Background Older heart failure (HF patients exhibit exercise intolerance during activities of daily living. We hypothesized that reduced lower extremity blood flow (LBF due to reduced forward cardiac output would contribute to submaximal exercise intolerance in older HF patients. Methods and Results Twelve HF patients both with preserved and reduced left ventricular ejection fraction (LVEF (aged 68 ± 10 years without large (aorta or medium sized (iliac or femoral artery vessel atherosclerosis, and 13 age and gender matched healthy volunteers underwent a sophisticated battery of assessments including a peak exercise oxygen consumption (peak VO2, b physical function, c cardiovascular magnetic resonance (CMR submaximal exercise measures of aortic and femoral arterial blood flow, and d determination of thigh muscle area. Peak VO2 was reduced in HF subjects (14 ± 3 ml/kg/min compared to healthy elderly subjects (20 ± 6 ml/kg/min (p = 0.01. Four-meter walk speed was 1.35 ± 0.24 m/sec in healthy elderly verses 0.98 ± 0.15 m/sec in HF subjects (p p ≤ 0.03. Conclusion During CMR submaximal bike exercise in the elderly with heart failure, mechanisms other than low cardiac output are responsible for reduced lower extremity blood flow.

  8. Kidney transplant artery stenosis. Interrelationship between blood pressure, kidney function, renin-aldosterone system and body sodium content.

    Science.gov (United States)

    Kornerup, H J; Pedersen, E B; Fjeldborg, O

    1977-01-01

    Among 9 hypertensive recipients with kidney transplant artery stenosis (KTAS) evidence of increased activity of the renin system was present in 3. Surgical repair of KTAS in 4 recipients resulted in an increase in renal plasma flow and glomerular filtration rate associated with a decrease in exchangeable sodium and blood pressure. Peripheral plasma renin and aldosterone values were normal before and after operation in all. It is suggested that sodium retention may counterbalance increased activity of the renin system in KTAS. Preoperative determinations of plasma renin do not predict the effect of surgical repair of KTAS on hypertension.

  9. Fetal middle cerebral artery blood flow characteristics of gestational hypertension combined with fetal distress in uterus as well as their correlation with hypoxia

    Institute of Scientific and Technical Information of China (English)

    Wei Yin; Jian-Hua Wang

    2017-01-01

    Objective:To study the fetal middle cerebral artery blood flow characteristics of gestational hypertension combined with fetal distress in uterus as well as their correlation with hypoxia. Methods: Puerperae with hypertensive disorders in pregnancy and fetal distress in uterus, puerperae with hypertensive disorders in pregnancy alone and healthy puerperae who gave birth in our hospital between January 2013 and January 2016 were included in group A, group B and group C of the study respectively. At 34-36 weeks of pregnancy, color Doppler ultrasonography was conducted to determine fetal middle cerebral artery blood flow parameters; after childbirth, umbilical arterial blood was collected to determine blood gas analysis parameters, and the placenta tissue was collected to determine oxidative stress and mitochondria damage indexes.Results:Fetal middle cerebral artery S/D, PI and RI of group A were significantly higher than those of group B and group C while umbilical artery pH value and PaO2 as well as HCO3- and BE content were significantly lower than those of group B and group C; fetal middle cerebral artery S/D, PI and RI as well as umbilical artery pH value, PaO2, HCO3- and BE content of group B were not significantly different from those of group C; Nrf2, ARE, NQO1, VitC, SVCT1, SVCT2, ATP, PGC-1α, PGC-1β, NRF1 and NRF2 content in placenta tissue of group A were significantly lower than those of group B and group C while ROS content was significantly higher than those of group B and group C; Nrf2, ARE, NQO1, VitC, SVCT1, SVCT2, ATP, PGC-1α, PGC-1β, NRF1 and NRF2 content in placenta tissue of group B were significantly lower than those of group C while ROS content was significantly higher than that of group C. Fetal middle cerebral artery S/D, PI and RI were negatively correlated with umbilical artery pH value, PaO2, HCO3- and BE content as well as Nrf2, ARE, NQO1, VitC, SVCT1, SVCT2, ATP, PGC-1α, PGC-1β, NRF1 and NRF2 content, and were positively correlated

  10. Nanostructural haemocompatible coatings for the internal side of artificial blood vessels

    Science.gov (United States)

    Trembecka-Wojciga, K.; Major, R.; Lackner, J. M.; Butruk-Raszeja, B.; Sanak, M.; Major, B.

    2016-03-01

    The main goal of the work was to elaborate low thrombogenicity of surface inside tube-like elements for cardiovascular system support by combination of low-temperature glow discharge and hydrogel coatings to inhibit blood-clotting cascade activation. A large share of amorphous phase silicon was observed in the microstructure analysis. The crystalline elements were uniformly distributed in the amorphous structure. Combination of low thickness, the proper microstructure and density of the coatings provided a highly flexible nature of the whole system. The blood-material interaction was analyzed in vitro in dynamic conditions by using a designed and fabricated novel blood flow simulator. Coatings deposited by the glow discharge expressed good hemocopatibile properties. The use of hydrogel coatings did not reduce coagulation parameter. Hydrogel coatings did not improve the hemocompatibility of the surface modified with carbon based coatings. Modification of surface with hydrogel resulted in further increased risk of hemolysis.

  11. Fractals and fractal dimension of systems of blood vessels: An analogy between artery trees, river networks, and urban hierarchies

    CERN Document Server

    Chen, Yanguang

    2015-01-01

    An analogy between the fractal nature of networks of arteries and that of systems of rivers has been drawn in the previous works. However, the deep structure of the hierarchy of blood vessels has not yet been revealed. This paper is devoted to researching the fractals, allometric scaling, and hierarchy of blood vessels. By analogy with Horton-Strahler's laws of river composition, three exponential laws have been put forward. These exponential laws can be reconstructed and transformed into three linear scaling laws, which can be named composition laws of blood vessels network. From these linear scaling laws it follows a set of power laws, including the three-parameter Zipf's law on the rank-size distribution of blood vessel length and the allometric scaling law on the length-diameter relationship of blood vessels in different orders. The models are applied to the observed data on human beings and animals early given by other researchers, and an interesting finding is that human bodies more conform to natural r...

  12. The Prognostic Role of Red Blood Cell Distribution Width in Coronary Artery Disease: A Review of the Pathophysiology

    Directory of Open Access Journals (Sweden)

    Kamil Bujak

    2015-01-01

    Full Text Available Red blood cell distribution width (RDW is a measure of red blood cell volume variations (anisocytosis and is reported as part of a standard complete blood count. In recent years, numerous studies have noted the importance of RDW as a predictor of poor clinical outcomes in the settings of various diseases, including coronary artery disease (CAD. In this paper, we discuss the prognostic value of RDW in CAD and describe the pathophysiological connection between RDW and acute coronary syndrome. In our opinion, the negative prognostic effects of elevated RDW levels may be attributed to the adverse effects of independent risk factors such as inflammation, oxidative stress, and vitamin D3 and iron deficiency on bone marrow function (erythropoiesis. Elevated RDW values may reflect the intensity of these phenomena and their unfavorable impacts on bone marrow erythropoiesis. Furthermore, decreased red blood cell deformability among patients with higher RDW values impairs blood flow through the microcirculation, resulting in the diminution of oxygen supply at the tissue level, particularly among patients suffering from myocardial infarction treated with urgent revascularization.

  13. The Prognostic Role of Red Blood Cell Distribution Width in Coronary Artery Disease: A Review of the Pathophysiology

    Science.gov (United States)

    Bujak, Kamil; Wasilewski, Jarosław; Osadnik, Tadeusz; Jonczyk, Sandra; Kołodziejska, Aleksandra; Gierlotka, Marek; Gąsior, Mariusz

    2015-01-01

    Red blood cell distribution width (RDW) is a measure of red blood cell volume variations (anisocytosis) and is reported as part of a standard complete blood count. In recent years, numerous studies have noted the importance of RDW as a predictor of poor clinical outcomes in the settings of various diseases, including coronary artery disease (CAD). In this paper, we discuss the prognostic value of RDW in CAD and describe the pathophysiological connection between RDW and acute coronary syndrome. In our opinion, the negative prognostic effects of elevated RDW levels may be attributed to the adverse effects of independent risk factors such as inflammation, oxidative stress, and vitamin D3 and iron deficiency on bone marrow function (erythropoiesis). Elevated RDW values may reflect the intensity of these phenomena and their unfavorable impacts on bone marrow erythropoiesis. Furthermore, decreased red blood cell deformability among patients with higher RDW values impairs blood flow through the microcirculation, resulting in the diminution of oxygen supply at the tissue level, particularly among patients suffering from myocardial infarction treated with urgent revascularization. PMID:26379362

  14. Estimated aortic blood pressure based on radial artery tonometry underestimates directly measured aortic blood pressure in patients with advancing chronic kidney disease staging and increasing arterial stiffness.

    Science.gov (United States)

    Carlsen, Rasmus K; Peters, Christian D; Khatir, Dinah S; Laugesen, Esben; Bøtker, Hans Erik; Winther, Simon; Buus, Niels H

    2016-10-01

    Central blood pressure (BP) can be assessed noninvasively based on radial tonometry and may potentially be a better predictor of clinical outcome than brachial BP. However, the validity of noninvasively obtained estimates has never been examined in patients with chronic kidney disease (CKD). Here we compared invasive aortic systolic BP (SBP) with estimated central SBP obtained by radial artery tonometry and examined the influence of renal function and arterial stiffness on this relationship. We evaluated 83 patients with stage 3 to 5 CKD (mean estimated glomerular filtration rate [eGFR] 30 ml/min/1.73 m(2)) and 41 controls without renal disease undergoing scheduled coronary angiography. BP in the ascending aorta was measured through the angiography catheter and simultaneously estimated using radial tonometry. The mean difference between estimated central and aortic SBP was -13.2 (95% confidence interval -14.9 to -11.4) mm Hg. Arterial stiffness was evaluated by carotid-femoral pulse wave velocity (cf-PWV) and was significantly increased in CKD patients compared with (versus) control patients (mean 10.7 vs. 9.3 m/s). The difference in BP significantly increased 1.0 mm Hg for every 10 ml/min decrease in eGFR and by 1.6 mm Hg per 1 m/s increase in cfPWV. Using multivariate regression analysis including both eGFR and cfPWV, the difference between estimated central and invasive aortic SBP was significantly increased by 0.7 mm Hg. For the entire cohort brachial SBP significantly better reflected invasive SBP than estimated SBP. Thus, tonometry-based estimates of central BP progressively underestimate invasive central SBP with decreasing renal function and increasing arterial stiffness in CKD patients.

  15. Prediction of air-to-blood partition coefficients of volatile organic compounds using genetic algorithm and artificial neural network

    Energy Technology Data Exchange (ETDEWEB)

    Konoz, Elahe [Department of Chemistry, Central Tehran Branch, Islamic Azad University, Tehran (Iran, Islamic Republic of); Golmohammadi, Hassan [Department of Chemistry, Mazandaran University, Babolsar (Iran, Islamic Republic of)], E-mail: hassan.gol@gmail.com

    2008-07-07

    An artificial neural network (ANN) was constructed and trained for the prediction of air-to-blood partition coefficients of volatile organic compounds. The inputs of this neural network are theoretically derived descriptors that were chosen by genetic algorithm (GA) and multiple linear regression (MLR) features selection techniques. These descriptors are: R maximal autocorrelation of lag 1 weighted by atomic Sanderson electronegativities (R1E+), electron density on the most negative atom in molecule (EDNA), maximum partial charge for C atom (MXPCC), surface weighted charge partial surface area (WNSA1), fractional charge partial surface area (FNSA2) and atomic charge weighted partial positive surface area (PPSA3). The standard errors of training, test and validation sets for the ANN model are 0.095, 0.148 and 0.120, respectively. Result obtained showed that nonlinear model can simulate the relationship between structural descriptors and the partition coefficients of the molecules in data set accurately.

  16. [Isolation and purification of human blood plasma proteins able to form potassium channels in artificial bilayer lipid membrane].

    Science.gov (United States)

    Venediktova, N I; Kuznetsov, K V; Gritsenko, E N; Gulidova, G P; Mironova, G D

    2012-01-01

    Protein fraction able to induce K(+)-selective transport across bilayer lipid membrane was isolated from human blood plasma with the use of the detergent and proteolytic enzyme-free method developed at our laboratory. After addition of the studied sample to the artificial membrane in the presence of 100 mM KCl, a discrete current change was observed. No channel activity was recorded in the presence of calcium and sodium ions. Channel forming activity of fraction was observed only in the presence of K+. Using a threefold gradient of KCl in the presence of studied proteins the potassium-selective potential balanced by voltage of -29 mV was registered. This value is very close to the theoretical Nernst potential in this case. This means that the examined ion channel is cation-selective. According to data obtained with MS-MALDI-TOF/TOF and database NCBI three protein components were identified in isolated researched sample.

  17. Arterial Blood Gas Analysis and the Outcome of Treatment in Tricyclic Antidepressants Poisoned Patients with Benzodiazepine Coingestion

    Directory of Open Access Journals (Sweden)

    Ahmad Yaraghi

    2015-01-01

    Full Text Available Background. Poisoning with tricyclic antidepressants (TCAs is still a major concern for emergency physicians and intensivists. Concomitant ingestion of other psychoactive drugs especially benzodiazepines with TCAs may make this clinical situation more complex. This study aimed to compare the arterial blood gas (ABG values and the outcome of treatment in patients with coingestion of TCA and benzodiazepine (TCA + BZD poisoning and TCA poisoning alone. Methods. In this cross-sectional study which was carried out in a tertiary care university hospital in Iran, clinical and paraclinical characteristics of one hundred forty TCA only or TCA + BZD poisoned patients (aged 18–40 years were evaluated. ABG analysis was done on admission in both groups. Outcomes were considered as survival with or without complication (e.g., intubation and the frequency of TCA poisoning complications. Results. Arterial pH was significantly lower in TCA + BZD poisoning group compared with TCA only poisoning group (7.34 ± 0.08 and 7.38 ± 0.08, resp.; P=0.02. However, other complications such as seizure, and the need for the endotracheal intubation were not significantly different. All patients in both groups survived. Conclusions. Concomitant TCA plus BZD poisoning may make the poisoned patients prone to a lower arterial pH level on hospital admission which may potentially increases the risk of cardiovascular complications in TCA poisoning.

  18. Cerebral blood flow and cerebrovascular reserve capacity in patients with occlusion or severe stenosis of cerebral arterial trunk

    Energy Technology Data Exchange (ETDEWEB)

    Yoshinaga, Shinya; Tanaka, Akira; Nakayama, Yoshiya; Tomonaga, Masamichi [Fukuoka Univ., Chikushino (Japan). Chikushi Hospital

    1997-12-01

    The cerebral blood flow (CBF) and the cerebrovascular reserve capacity (CVRC) were sequentially measured using a xenon enhanced CT scan in patients with transient ischemic attack or minor stroke due to an occlusion or a severe stenosis of the cerebral arterial trunk. The patients consisted of twelve males and one female ranging from 37 to 71 years of age (53 years on average). The vascular lesion was located in the internal carotid artery (7 patients) and in the middle cerebral artery (6 patients). Eleven patients received antiplatelet drug therapy, while two other patients underwent STA-MCA anastomosis. The CBF measurements were initially done within one month after the attack and then from 6 to 24 months (12 months on average) after the first study. Only one of 13 patients demonstrated a reattack during the period of observation and the CVRC decreased to 0% from the 14% level observed prior to the reattack, although the CBF was preserved. In the other twelve patients without a reattack, the CVRC was found to improve to 29.4% from 9.9% with statistical significance, even though the CBF remained the same in the first study. This study suggests hemodynamic insult to be closely related to the decreased in the CVRC, while STA-MCA anastomosis does not for prevent hemodynamic reattack based on a decrease in the CVRC in the early stage. (author)

  19. Endovascular internal carotid artery trapping for ruptured blood blister-like aneurysms: long-term results from a single centre

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Byong-Cheol [Dongguk University Ilsan Hospital, Department of Neurosurgery, Goyang (Korea, Republic of); Kwon, O-Ki; Oh, Chang Wan; Bang, Jae Seung; Hwang, Gyojun [Seoul National University Bundang Hospital, Department of Neurosurgery, Seongnam, Gyeonggi (Korea, Republic of); Jin, Sung-Chul [Inje University Haeundae Paik Hospital, Department of Neurosurgery, Busan (Korea, Republic of); Park, Hyun [Gyeongsang National University Hospital, Department of Neurosurgery, Gyeongsangnam-do (Korea, Republic of)

    2014-03-15

    Endovascular internal carotid artery (ICA) trapping was performed to treat ruptured blood blister-like aneurysms (BBAs). The aim of this study was to evaluate the procedural risks and long-term follow-up results. The records of 11 consecutive patients with BBAs who underwent endovascular ICA trapping between 2005 and 2010 were reviewed. Clinical outcomes were assessed with modified Rankin Scale (mRS) scores. Endovascular ICA trapping was performed in 11 patients as either the primary treatment (7 patients) or the secondary treatment (4 patients) after the patient underwent other treatments. Three patients underwent superficial temporal artery (STA)-middle cerebral artery (MCA) bypass when balloon test occlusion (BTO) revealed inadequate collateral circulation. In the primary ICA trapping group (seven patients), six patients had good outcomes (mRS 0 in five, mRS 1 in one), and one patient had a poor outcome (mRS 6: dead). In the secondary ICA trapping group (four patients), two patients had good outcomes (mRS 0), and two patients had poor outcomes (mRS 4, 5). All ten of the surviving patients were clinically stable during the follow-up period (mean 39 months). A radiological follow-up of nine patients (mean 22 months) demonstrated stable occlusion, with the exception of one reopening of the ICA because of coil migration. Perfusion studies of nine patients (mean: 23 months) demonstrated no perfusion decrease. Endovascular ICA trapping is an effective and durable treatment for BBAs. (orig.)

  20. Quantification of blood flow velocity in stenosed arteries by the use of finite elements: an observer-independent noninvasive method.

    Science.gov (United States)

    Mühlthaler, Hannes; Quatember, Bernhard; Fraedrich, Gustav; Mühlthaler, Markus; Pfeifer, Bernhard; Greiner, Andreas; Schocke, Michael F H

    2008-10-01

    Interventions for peripheral arterial disease should be designed to treat a physiological rather than an anatomic defect. Thus, for vascular surgeons, functional information about stenoses is as important as the anatomic one. In case of finding a stenosis by the use of magnetic resonance angiography, it would be a matter of particular interest to derive automatically and directly objective information about the hemodynamic influence on blood flow, caused by patient-specific stenoses. We developed a methodology to noninvasively perform numerical simulations of a patient's hemodynamic state on the basis of magnetic resonance images and by the means of the finite element method. We performed patient-specific three-dimensional simulation studies of the increase in systolic blood flow velocity due to stenoses using the commercial computational fluid dynamic software package FIDAP 8.52. The generation of a mesh defining the flow domain with a stenosis and some simulation results are shown.

  1. Study on blood flow containing nanoparticles through porous arteries in presence of magnetic field using analytical methods

    Science.gov (United States)

    Ghasemi, Seiyed E.; Hatami, M.; Sarokolaie, A. Kalani; Ganji, D. D.

    2015-06-01

    In this paper, flow analysis for a third grade non-Newtonian blood in porous arteries in presence of magnetic field is simulated analytically and numerically. Blood is considered as the third grade non-Newtonian fluid containing nanoparticles. Collocation Method (CM) and Optimal Homotopy Asymptotic Method (OHAM) are used to solve the Partial Differential Equation (PDE) governing equation which a good agreement between them was observed in the results. The influences of the some physical parameters such as Brownian motion parameter, pressure gradient and thermophoresis parameter, etc. on temperature, velocity and nanoparticles concentration profiles are considered. For instance, increasing the thermophoresis parameter (Nt) caused an increase in temperature values in whole domain and an increase in nanoparticles concentration near the inner wall.

  2. Investigating Sodium Nitrite Effect on Blood Nitric Oxide and Histopathologic Changes on Pulmonary Artery in Adult Male Rats

    Directory of Open Access Journals (Sweden)

    F Joibar

    2013-12-01

    Results: The outcome of nitric oxide plasmatic density measurement showed that nitric oxide level in animal ’s blood in 175 mg/kg/day dose recipient group and 350 mg/kg/day dose recipient group increased significantly compared with the control group at the level of P ≤ 0.05. Also thickness of media layer decreased in maximum dose group (350 mg/kg/day dose compared to the control group. Conclusion: Based on the results of different doses of sodium nitrite, the nitric oxide levels in the blood were increased, and the thickness of middle layer of the lung arteries at dose 350 mg of sodium nitrite was reduced.

  3. Real-time characterization of the uterine blood flow in mares before and after artificial insemination.

    Science.gov (United States)

    Ferreira, J C; Ignácio, F S; Rocha, N S; Thompson, D L; Pinto, C R; Meira, C

    2015-09-01

    The present experiment was divided into two studies to investigate the effect of age and endometrial degeneration on uterine blood flow of mares throughout the immediate post-breeding period. In study 1, uterine blood flow was characterized in mares (n = 7 mares/group) with minimal, moderate or severe endometrial degenerative changes (GI, GII and GIII, respectively). In study 2, the effect of age was investigated using young (≤ 6 years) and old (≥ 15 years) mares (n = 7 mares/group). Uterine vascular perfusion and mesometrial pulsatility index (PI) were evaluated every hour from H0 (moment immediately before AI) to H12. In study 1, a pronounced and transitory increase on uterine vascular perfusion was detected (P blood flow. In study 2, a transitory increase on uterine vascular perfusion was also observed in both age groups during the first hour after mating. However, mesometrial PI of young and old mares was similar (P > 0.05) and constant (P > 0.7) through the first 12h after AI. Results demonstrated, for the first time, the immediate changes on uterine vascular perfusion and mesometrial PI in response to semen infusion. Moreover, reduced blood flow of the uterus during the post-breeding period was strongly associated with endometrial degenerative changes in mares, regardless of age.

  4. The effects of hypotension on differences between the results of simultaneous venous and arterial blood gas analysis

    Directory of Open Access Journals (Sweden)

    Farhad Shirani

    2011-01-01

    Full Text Available Background: Analysis of venous blood gas (VBG can represent arterial blood gas (ABG analysis in patients with various diseases. The effects of hypotension on differences between the results of simultaneous venous and arterial blood gas analyses were reviewed. Methods: This observational, cross-sectional study was conducted from March to October 2010 in emergency depart-ments of two university hospitals in Tehran (Iran on consecutive adult patients for whom ABG had been indicated for diagnosis/treatment. Arterial and peripheral venous bloods were simultaneously sampled with blood pressure measure-ment. The VBG-ABG amount of difference regarding pH, HCO 3 , PCO 2 , PO 2 , SO 2 , and Base Excess (BE was com-pared between those with and without hypotension. Results: During the study, 192 patients (51.6 ± 23.6 years, 67.7% males were entered into the hypotension (n = 78 and normotensive groups (n = 114. The average VBG-ABG amount of difference (95% limits of agreement in the hypotension versus normotensive group were -0.030 (-0.09 to 0.03 vs. -0.016 (-0.1 to 0.068 for pH (p = 0.01, 1.79 (-1.91 to 5.49 vs. 1.32 (-1.94 to 4.58 mEq/L for HCO 3 (p = 0.032, 2.69 (-20.43 to 25.81 vs. 2.03 (-7.75 to 11.81 mmHg for PCO 2 (p = 0.295, -35.97 (-130.17 to 58.23 vs. -32.65 (-104.79 to 39.49 mmHg for PO 2 (p = 0.293, -18.58 (-14.66 to 51.82 vs. -9.06 (-31.28 to 13.16 percent (p < 0.001 for SO 2 , and 0.25 (-3.73 to 4.23 vs. 0.79 (-2.51 to 4.09 for BE (p = 0.036. Conclusions: Hypotensive status is associated with an increase in the amount of difference between VBG and ABG analysis regarding pH, HCO 3 , and BE, though the amount of increase does not seem to be clinically important. Studying the precise effects of replacing ABG with VBG on the clinical decision-making and the following outcomes is worth-while.

  5. [The biological reaction of inflammation, methylglyoxal of blood plasma, functional and structural alterations in elastic type arteries at the early stage of hypertension disease].

    Science.gov (United States)

    Titov, V N; Dmitriev, V A; Oshchepkov, E V; Balakhonova, T V; Tripoten', M I; Shiriaeva, Iu K

    2012-08-01

    The article deals with studying of the relationship between biologic reaction of inflammation with glycosylation reaction and content of methylglyoxal in blood serum. The positive correlation between pulse wave velocity and content of methylglyoxal, C-reactive protein in intercellular medium and malleolar brachial index value was established. This data matches the experimental results concerning involvement of biological reaction of inflammation into structural changes of elastic type arteries under hypertension disease, formation of arteries' rigidity and increase of pulse wave velocity. The arterial blood pressure is a biological reaction of hydrodynamic pressure which is used in vivo by several biological functions: biological function of homeostasis, function of endoecology, biological function of adaptation and function of locomotion. The biological reaction of hydrodynamic (hydraulic) pressure is a mode of compensation of derangement of several biological functions which results in the very high rate of hypertension disease in population. As a matter of fact, hypertension disease is a syndrome of lingering pathological compensation by higher arterial blood pressure of the biological functions derangements occurring in the distal section at the level of paracrine cenoses of cells. The arterial blood pressure is a kind of in vivo integral indicator of deranged metabolism. The essential hypertension disease pathogenically is a result of the derangement of three biological functions: biological function of homeostasis, biological function of trophology - nutrition (biological reaction of external feeding - exotrophia) and biological function of endoecology. In case of "littering" of intercellular medium in vivo with nonspecific endogenic flogogens a phylogenetically earlier activation of biological reactions of excretion, inflammation and hydrodynamic arterial blood pressure occur. In case of derangement of biological function of homeostasis, decreasing of

  6. Analysis of feasibility of blood cell count in blood emergency arterial blood gas%急诊动脉血气分析用血进行血细胞计数的可行性探讨

    Institute of Scientific and Technical Information of China (English)

    黄万仁; 张桂芬; 张杰雄

    2014-01-01

    Objective To explore the feasibility of blood cell count in blood emergency arterial blood gas. Methods 153 patients of the emergency department of our hospital in 2008 March to 2013October were collected,arterial blood gas analysis andblood cell count were performed in all patients at the same time were all observed. Results Venous blood and the instant blood blood cell counts were compared,comparison of MCV,MCH,MCHC,MPV, PDW,P-LCR,BASO,the difference was statistically significant(P < 0.05);and the venous blood and the half hour blood blood cell counts were compared,comparison of HGB,HCT,RWD-SD,RWD-CV,PLT PDW,P-LCR,MPV,LYMPH,BASO,etc,the difference was statistically significant(P < 0.05). There are differences between the index of the linear analysis,venous blood and theinstant blood, half an hour of arterial blood indicators are positively correlated with significant(P < 0.05). Conclusion Analysis of blood transfusion in emergency inspection of arterial blood gas, in the instant conditions analysis of alternative venous blood forblood cell count.%目的:探讨急诊动脉血气分析用血进行血细胞计数的可行性。方法选取2008年3月~2013年10月我院急诊科进行治疗的患者153例,所有患者同时进行动脉血气分析和静脉血细胞计数分析。结果静脉血与即时动脉血血细胞计数均数比较,MCHC、MCV、MCH、MPV、P-LCR、BASO、PDW等指标比较,差异有统计学意义(P<0.05);而静脉血与半小时动脉血血细胞计数均数比较,HGB、HCT、RWD-SD、RWD-CV、PLT、MPV、PDW、P-LCR、LYMPH、BASO等比较,差异有统计学意义(P<0.05)。对各项有差异的指标做线性分析,即时动脉血、半小时动脉血各项指标与静脉血呈正相关关系(P<0.05)。结论动脉血气分析用血急诊检验中,在即时条件下可以替代静脉血行全血细胞计数分析。

  7. [A dynamic study of blood flow in patients with unilateral obstruction of the iliac artery].

    Science.gov (United States)

    Moreno Padilla, F; Díez Herranz, M; Peñafiel Marfil, R; García Rospide, V; González Ríos, L; Ramosa Bruno, J; Ros Die, E

    1991-01-01

    Sanguineous flow is studied in a group of patients with unilateral obliteration of iliac artery. This flow was particularly studied during exercise with the purpose of determinate the modifications on the flow produced by exercise. For this purpose, 11 patients with no associated pathologies were studied during more than a year follow-up.

  8. Blood supply of the posterior cerebral artery by the carotid system on angiograms

    NARCIS (Netherlands)

    Jongen, JCF; Franke, CL; Soeterboek, AAJGM; Versteege, CWM; Ramos, LMP; van Gijn, J

    2002-01-01

    Background and Purpose Occipital lobe infarcts are traditionally attributed to vertebrobasilar disease. However, anatomical studies indicate that in some people the supply of the posterior cerebral artery is via the carotid system. We investigated how often such a developmental variant in the cerebr

  9. Renal Fractional Excretion of Sodium in Relation to Arterial Blood Gas and Spirometric Parameters in Chronic Obstructive Pulmonary Disease

    Directory of Open Access Journals (Sweden)

    Fariba Rezaeetalab

    2014-05-01

    Full Text Available Introduction: Arterial gas derangement could change urinary sodium excretion in Chronic Obstructive Pulmonary Disease (COPD patients.There are very few and conflicting data in regards to the measurement of fractional excretion of sodium in COPD patients. The main aim of this study was to assess the relationship between renal fractional excretion of sodium(FeNa with arterial blood gas and spirometric parameters in COPD. Materials and Methods: This study was a cross-sectional study performed on 40 consecutive stable COPD outpatients in 2 main general hospitals (Emam Reza, Ghaem in Mashhad/Iran between 2011 and 2012. We investigated the relationship of renal FeNa with arterial blood gas parameters including HCO3, PH, PaCO2 and PaO2, and spirometric parameters. Analysis was done by SPSS v16 with a statistically meaningful p value of less than 0.05. Results: Mean age was 65.97±10.77 SD years and female to male ratio was 0.26. A renal FeNa of less than 1% was presented in 27% patients. There was a significant, positive relationship between renal FeNa and PaO2 (P=0.005, r=0.456. The correlations between PaCO2, HCO3, PH and spirometric parameters were not seen (P>0.05, but there was a significant relationship between Urine Na and PaO2. Outstanding, it seems likely that kidneys of COPD patients are responsible for sodium retaining state particularly in the presence of hypoxemia. Conclusion: This study indicates that in COPD patients, PaO2 but not PaCO2 is related to renal FeNa which shows the probable role of hypoxemia on sodium output in COPD patients. However, some caution is needed for interpretation of the probable role of hypercapnia on sodium retention in COPD.

  10. 髂外-腘动脉人工血管交叉转流术治疗髂股动脉硬化闭塞症%External iliac-popliteal artery artificial graft cross bypass for the treatment of arterial occlusion in lilac-femoral arteriosclerosis

    Institute of Scientific and Technical Information of China (English)

    马杰; 马韬

    2009-01-01

    Objective To study the curative effectiveness of external iliac-popliteal artery artificial graft cross bypass in treating extensive arterial occlusion in unilateral lilac-femoral arteriosclerosis. Methods From Sep. 1999 to Oct. 2007, 39 elder patients were diagnosed as having extensive arterial occlusion in unilateral lilac-femoral arteriosclerosis by color Doppler ultrasonography, CTA or DSA. 25 patients (61.5%) had resting pain, 14 had ulcers or gangrenes in the toes. The average ankle-brachial index was 0. 19. Contralateral external iliac-popliteal artery artificial graft cross bypass surgeries were performed on 22 patients from left to right, the other 17 were from right to left. Results There were no perioperative death or amputation. The ankle-brachial index increased from 0 ~ 0. 41 ( preoperative ) to 0. 85 ~ 1.02(postoperative) ; the claudication distance increased from 15 ~ 60 m (preoperative) to 350 ~ 500 m or more than 500 m [ postoperatively at the speed of (100 ~ 120) m/min] ; The postoperative color Doppler uhrasonography showed the average velocity of the popliteal artery was 45 cm/s. In the anterior tibial artery or the posterior tibial artery, little blood flow was showed in preoperative color Doppler ultrasonography examination, the postoperative average blood flow velocity was 41 cm/s. 35 patients (89. 7% ) were followed up for an average of 3.4 years, with an accumulative patency rate of 85.7%. Four patients had amputation, the limb salvage rate is 88.6%. Conclusion External iliac-popliteal artery artificial graft cross bypass is effective in treating unilateral lilac-femoral arterial occlusion, particularly for aged patients with vital organ incompetence.%目的 探讨髂外动脉-腘动脉人工血管移植交义转流术治疗单侧髂股动脉硬化广泛性闭塞的疗效.方法 1999年9月至2007年10月39例患者经血管彩超、CT血管造影(CTA)或数字减影血管造影(DSA)检查,证实单侧髂股动脉

  11. Comparison of Arterial Blood Collection at Different Needle Angle%不同进针角度采集动脉血的比较

    Institute of Scientific and Technical Information of China (English)

    王晓颖

    2016-01-01

    血气分析是判定呼吸衰竭和各种抢救治疗措施是否有效的重要指标,而血气分析的最佳标本是动脉血,快速、准确地采集动脉血则是非常关键的。要快速准确地采集动脉血,减轻患者的痛苦,可根据动脉情况采取不同的进针角度进行穿刺,以提高动脉采血的成功率、准确率。本文分别介绍了桡动脉、股动脉、肱动脉、足背动脉不同进针角度采血的方法及结果,得出结论:在采集动脉的过程中应根据患者的不同情况选择不同的方法,从而提高穿刺采血的成功率及准确率,提高护理质量。%Blood gas analysis is an important index of respiratory failure and various treatment measures are effective, and the best specimens of blood gas analysis is blood, collected quickly and accurately is very important in arterial blood. To quickly and accurately collect arterial blood, reduce the pain of patients, according to the circumstances of the artery to take different angle of the needle to puncture, to improve the success rate of arterial blood collection, accuracy rate. This paper introduces the methods and results of blood sampling from different angles of the radial artery, femoral artery, brachial artery and dorsal artery of the foot: We should choose different methods according to the different situations of the patients in the process of collecting the artery, so as to improve the success rate and accuracy of puncture and blood collection, and improve the quality of nursing.

  12. Can we measure the spiral and uterine artery blood flow by real-time sonography and Doppler indices to predict spontaneous miscarriage in a normal-risk population?

    Science.gov (United States)

    Özkan, Mehmet Burak; Ozyazici, Elif; Emiroglu, Baris; Özkara, Enis

    2015-05-01

    Introduction: The predictive value of spiral artery flow Doppler measurements of a subsequent early miscarriage in first trimester pregnancy is explored here. Objective: The aim of this study is to determine uterine and spiral artery blood flow changes in first trimester subsequent miscarriages and correlate within the mechanisms of the Doppler indicies. Study design: The uterine artery and spiral artery pulsatility and resistance indexes, systolic and diastolic ratios, acceleration times, and blood flow of both the right and left uterine arteries were obtained by trans vaginal color Doppler ultrasonography in consecutive viable pregnancies between 5 and 12 gestational week. Women were subsequently classified as having continuing pregnancies or pregnancy loss before 20 weeks gestation. To predict subsequent pregnancy loss, Doppler findings were adjusted for maternal age, history of previous abortion, presence of subchorionic hematoma, embryonic bradycardia, and gestational age by means of multivariate logistic regression analysis. The cut-off values are used for the ROC curve. Results: Twenty-five pregnancies (11.7%) were spontaneously aborted before 20 weeks of gestational age. In 29 (13.6%) cases there were previously abortion history, 30 (14%) had bradycardia, and 37 (17.3%) had subchoronic hematoma. Regarding the parameters of uterine and spiral artery pulsatility and resistive index, acceleration time, systolic/diastolic ratios and blood flows, only uterine artery S/D low values were significantly associated with pregnancy loss in the multivariate logistic regression analysis (P = 0.0001,95% CI: 4.968-55.675). Conclusion: The uterine artery systolic/diastolic ratios have a predictive value for early pregnancy loss and seem to be useful as a marker. On the other hand, spiral artery changes could be so local that they cannot be determined by the parameters of spectral Doppler techniques. This suggests that uterine vascular bed alterations should be measured to

  13. Evaluation of changes of intracranial blood flow after carotid artery stenting using digital subtraction angiography flow assessment

    Institute of Scientific and Technical Information of China (English)

    Hajime; Wada; Masato; Saito; Kyousuke; Kamada

    2015-01-01

    AIM: To evaluate the changes of intracranial blood flow after carotid artery stenting(CAS), using the flow assessment application "Flow-Insight", which was developed in our department.METHODS: Twenty patients treated by CAS participated in this study. We analyzed the change in concentration of the contrast media at the anterior-posterior and profile view image with the flow assessment application "Flow-Insight". And we compared the results with N-isopropyl-p-[123I] iodoamphetamine-single-photon emission computed tomography(IMP SPECT) performed before and after the treatment. RESULTS: From this study, 200% of the parameter "blood flow" change in the post/pre-treatment is suggested as the critical line of the hyperperfusion syndrome arise. Although the observed blood flow increase in the digital subtraction angiography system did not strongly correlate with the rate of increase of SPECT, the "Flow-Insight" reflected the rate of change of the vessels well. However, for patients with reduced reserve blood flow before CAS, a highly elevated site was in agreement with the site analysis results. CONCLUSION: We concluded that the cerebral angiography flow assessment application was able to more finely reveal hyperperfusion regions in the brain after CAS compared to SPECT.

  14. Roles of myocardial blood volume and flow in coronary artery disease: an experimental MRI study at rest and during hyperemia

    Energy Technology Data Exchange (ETDEWEB)

    McCommis, Kyle S.; Goldstein, Thomas A.; Pilgram, Thomas [Washington University School of Medicine, Mallinckrodt Institute of Radiology, St. Louis, MO (United States); Abendschein, Dana R. [Washington University School of Medicine, Center for Cardiovascular Research, St. Louis, MO (United States); Misselwitz, Bernd [Bayer Schering Pharma AG, Berlin (Germany); Gropler, Robert J. [Washington University School of Medicine, Mallinckrodt Institute of Radiology, St. Louis, MO (United States); Washington University School of Medicine, Center for Cardiovascular Research, St. Louis, MO (United States); Zheng, Jie [Washington University School of Medicine, Mallinckrodt Institute of Radiology, St. Louis, MO (United States); Cardiovascular Imaging Lab, St. Louis, MO (United States)

    2010-08-15

    To validate fast perfusion mapping techniques in a setting of coronary artery stenosis, and to further assess the relationship of absolute myocardial blood volume (MBV) and blood flow (MBF) to global myocardial oxygen demand. A group of 27 mongrel dogs were divided into 10 controls and 17 with acute coronary stenosis. On 1.5-T MRI, first-pass perfusion imaging with a bolus injection of a blood-pool contrast agent was performed to determine myocardial perfusion both at rest and during either dipyridamole-induced vasodilation or dobutamine-induced stress. Regional values of MBF and MBV were quantified by using a fast mapping technique. Color microspheres and {sup 99m}Tc-labeled red blood cells were injected to obtain respective gold standards. Microsphere-measured MBF and {sup 99m}Tc-measured MBV reference values correlated well with the MR results. Given the same changes in MBF, changes in MBV are twofold greater with dobutamine than with dipyridamole. Under dobutamine stress, MBV shows better association with total myocardial oxygen demand than MBF. Coronary stenosis progressively reduced this association in the presence of increased stenosis severity. MR first-pass perfusion can rapidly estimate regional MBF and MBV. Absolute quantification of MBV may add additional information on stenosis severity and myocardial viability compared with standard qualitative clinical evaluations of myocardial perfusion. (orig.)

  15. Predicting drug penetration across the blood-brain barrier: comparison of micellar liquid chromatography and immobilized artificial membrane liquid chromatography.

    Science.gov (United States)

    De Vrieze, Mike; Lynen, Frédéric; Chen, Kai; Szucs, Roman; Sandra, Pat

    2013-07-01

    Several in vitro methods have been tested for their ability to predict drug penetration across the blood-brain barrier (BBB) into the central nervous system (CNS). In this article, the performance of a variety of micellar liquid chromatographic (MLC) methods and immobilized artificial membrane (IAM) liquid chromatographic approaches were compared for a set of 45 solutes. MLC measurements were performed on a C18 column with sodium dodecyl sulfate (SDS), polyoxyethylene (23) lauryl ether (Brij35), or sodium deoxycholate (SDC) as surfactant in the micellar mobile phase. IAM liquid chromatography measurements were performed with Dulbecco's phosphate-buffered saline (DPBS) and methanol as organic modifier in the mobile phase. The corresponding retention and computed descriptor data for each solute were used for construction of models to predict transport across the blood-brain barrier (log BB). All data were correlated with experimental log BB values and the relative performance of the models was studied. SDS-based models proved most suitable for prediction of log BB values, followed closely by a simplified IAM method, in which it could be observed that extrapolation of retention data to 0% modifier in the mobile phase was unnecessary.

  16. THE EFFECT OF FLUOROCARBON ARTIFICIAL BLOOD (FC-34 IN ACUTE VASOGENIC BRAIN EDEMA

    Directory of Open Access Journals (Sweden)

    M NEEMATBAKHSH

    2000-03-01

    Full Text Available Background. Oxygen transport to tissue after an acute ischemia is strongly important. Fluorocarbon liquids are able to facilitated the oxygen transport. An animal experiment was designed to study the effect of FC-34 in acute brain ischemia. Methods. The left common carotid arteries were ligated in three groups of anesthetized animals for 30 minutes to obtain acute brain edema. The animals were subjected to received 15 ml/kg saline (group 1, 10% monitol (group 2 or FC-43 (group 3. All animals were recovered, and they monitored for two weeks. The electrolytes, BUN, and creatinine were measured before (all animals and after two weeks (survived animals. Pathological investigation was obtained by light and electron microscope via pathological process. Findings. The group 1 animals were died during first five days, but one and four animals were survived by two weeks in groups 2 & 3 respectively (P < 0.05. The pathological determinations indicate less cellular damages in group 3. No significant differences were detected in potassium, calcium, BUN, and creatinine before and after the experiment. Conclusion. The particle size and oxygen solubility in FC-43 is the major factors for better oxygen transport in ischem

  17. Concentrations of C-reactive protein, serum amyloid A, and haptoglobin in uterine arterial and peripheral blood in bitches with pyometra.

    Science.gov (United States)

    Dąbrowski, Roman; Kostro, Krzysztof; Szczubiał, Marek

    2013-09-15

    Pyometra is a life-threatening reproductive disorder that affects the uterus of female dogs. This study was designed to identify the possible indicators of uterine inflammation by comparing C-reactive protein (CRP), serum amyloid A (SAA), and haptoglobin (Hp) concentrations in uterine arterial and peripheral venous blood in bitches with open- and closed-cervix pyometra. CRP, SAA, and Hp concentrations were higher in bitches with closed-cervix pyometra irrespective of the site of blood collection. Higher acute-phase protein concentrations were observed in peripheral compared with uterine arterial blood in bitches with closed-cervix pyometra, whereas the levels were comparable in dogs with open-cervix pyometra. Our results indicate that mean acute-phase protein concentrations differ according to pyometra type/severity and blood source and suggest the possible use of peripheral blood levels of CRP, SAA, and Hp to monitor inflammation during the course of pyometra.

  18. Blood loss in coronary artery bypass surgery : etiology, diagnosis and prevention

    NARCIS (Netherlands)

    Gielen, C.

    2016-01-01

    Blood loss requiring transfusions, and, in some cases even surgical re-exploration, is relatively common after cardiac surgery. There are several factors associated with this blood loss that can be separated into bleeding complications with a surgical origin (bleeding vessel, anastomosis or other su

  19. Increases in arterial blood oxygen during exercise in the lemon shark (Negaprion brevirostris)

    DEFF Research Database (Denmark)

    BUSHNELL, PG; LUTZ, PL; STEFFENSEN, JF;

    1982-01-01

    Polyethylene cannulae were implanted in pre- and post-branchial blood vessels allowing nonstressful blood sampling over a variety of activity ranges in an active tropical elasmobranch, the lemon shark (Negaprion brevirostris). TheP 50 was found to be 11.8 Torr at 24°C and pH of 7.7. A Bohr shift...

  20. Comparison of arterial and venous blood gases and the effects of analysis delay and air contamination on arterial samples in patients with chronic obstructive pulmonary disease and healthy controls.

    LENUS (Irish Health Repository)

    O'Connor, T M

    2012-01-31

    BACKGROUND: Arterial blood gases (ABGs) are often sampled incorrectly, leading to a \\'mixed\\' or venous sample. Delays in analysis and air contamination are common. OBJECTIVES: We measured the effects of these errors in patients with chronic obstructive pulmonary disease (COPD) exacerbations and controls. METHODS: Arterial and venous samples were analyzed from 30 patients with COPD exacerbation and 30 controls. Venous samples were analysed immediately and arterial samples separated into non-air-contaminated and air-contaminated specimens and analysed at 0, 30, 60, 90 and 180 min. RESULTS: Mean venous pH was 7.371 and arterial pH was 7.407 (p < 0.0001). There was a correlation between venous and arterial pH (r = 0.5347, p < 0.0001). The regression equation to predict arterial pH was: arterial pH = 4.2289 + 0.43113 . venous pH. There were no clinically significant differences in arterial PO associated with analysis delay. A statistically significant decline in pH was detected at 30 min in patients with COPD exacerbation (p = 0.0042) and 90 min in controls (p < 0.0001). A clinically significant decline in pH emerged at 73 min in patients with COPD exacerbation and 87 min in controls. Air contamination was associated with a clinically significant increase in PO in all samples, including those that were immediately analyzed. CONCLUSIONS: Arterial and venous pH differ significantly. Venous pH cannot accurately replace arterial pH. Temporal delays in ABG analysis result in a significant decline in measured pH. ABGs should be analysed within 30 min. Air contamination leads to an immediate increase in measured PO, indicating that air-contaminated ABGs should be discarded.

  1. Common Carotid Artery Ligation to Minimize Blood Loss During Oral and Maxillofacial Surgery.

    Science.gov (United States)

    Goodman, Alice E; Goodman, Andrew R

    2016-09-01

    Oral and maxillofacial surgery in veterinary medicine carries the risk of severe hemorrhage due to the great vascular supply of the head. Temporary hemostasis can be achieved with the application of pressure or hemostatic agents, but more definitive treatment may be needed to ensure bleeding will not resume once the patient is awake and normotensive. (1 , 2) Actively bleeding vessels encountered during maxillofacial surgery may be inaccessible, and vessels may recoil into bone, sometimes preventing definitive ligation. These scenarios may require ligation of the common carotid artery. (1) The purpose of this paper is to describe how to perform ligation of the common carotid artery in a step-by-step fashion. Both temporary and permanent ligation techniques are described.

  2. Effects of soy supplementation on blood lipids and arterial function in hypercholesterolaemic subjects

    DEFF Research Database (Denmark)

    Hermansen, K; Hansen, B; Jacobsen, R

    2005-01-01

    BACKGROUND: Studies on soy supplementation suggest a cardioprotective potential. OBJECTIVE: To examine the effects on LDL cholesterol and arterial function as a result of dietary enrichment with soy supplementation. DESIGN: A Randomized, double blind, parallel intervention trial. SETTING......: Subjects were randomly assigned to 24 weeks of daily intake of either a soy supplement, Abalon (30 g soy protein, 9 g cotyledon fibre and 100 mg isoflavones) or placebo (30 g of casein). The soy supplement and placebo were provided in two sachets daily that were stirred in water. Fasting plasma lipids, TNF...... in 32 subjects, arterial dilatory capacity, compliance, and distensibility were recorded before and after the intervention. RESULTS: In the main study, no difference in fasting plasma lipid levels or insulin sensitivity was found between soy-based supplement and placebo. A significant postprandial...

  3. Pulmonary intravascular blood volume changes through the cardiac cycle in healthy volunteers studied by cardiovascular magnetic resonance measurements of arterial and venous flow

    Directory of Open Access Journals (Sweden)

    Arheden Hakan

    2009-10-01

    Full Text Available Abstract Background This study aims to present a novel method for using cardiovascular magnetic resonance (CMR to non-invasively quantify the variation in pulmonary blood volume throughout the cardiac cycle in humans. Methods 10 healthy volunteers (7 males, 3 female, age range 21-32 years were studied. The blood flow in the pulmonary artery and all pulmonary veins was quantified during free breathing using phase contrast velocity encoded CMR. The difference in flow between the pulmonary artery and the pulmonary veins was integrated to calculate the change in pulmonary blood volume throughout the cardiac cycle. Results The stroke volumes in the pulmonary artery and the sum of the pulmonary veins were (mean ± SEM 103 ± 6 ml and 95 ± 6 ml, respectively. The pulmonary blood volume variation (PBVV was 48 ± 5 ml, and the PBVV expressed as percent of the pulmonary artery stroke volume was 46 ± 3%. The maximum increase in pulmonary blood volume occurred 310 ± 12 ms after the R-wave from the ECG (32 ± 2% of the cardiac cycle. PBVV did not correlate to change in cross-sectional area in the pulmonary artery (R2 = 0.03, p = 0.66. Conclusion It is feasible to non-invasively quantify the change in pulmonary blood volume during the cardiac cycle in humans using CMR. The average pulmonary blood volume variation in healthy volunteers was approximately 50 ml and this was approximately 50% of the stroke volume. Further studies are needed to assess the utility of the pulmonary blood volume variation as a measure for identifying cardiac and pulmonary vascular disease.

  4. Effect of Algerian Varieties Dates on Glycemic, Arterial Blood Pressure and Satiety Responses

    OpenAIRE

    Gourchala Freha, Mihoub Fatma, Derradj Meriem, Henchiri Cherifa

    2016-01-01

    The purpose of our study is to determine the Glycemic Indexes (GIs)of three Algerians varieties of dates in healthy subjects, evaluate the satiety and effect on arterial pressure after their consumption. We have first documented the chemical composition of the dates. 10 healthy subjects consumed the dates (carbohydrates content of 50 g) in order to determine the GIs. The responses of glycaemia were monitored during two hours after the dates taking and compared to the reference glucose. In a r...

  5. Vital Signs – Presión arterial alta (High Blood Pressure)

    Centers for Disease Control (CDC) Podcasts

    2012-10-02

    En los EE. UU. casi un tercio de la población adulta tiene presión arterial alta, el principal factor de riesgo de enfermedades cardiacas y accidentes cerebrovasculares, dos de las principales causas de muerte en el país.  Created: 10/2/2012 by National Center for Chronic Disease Prevention and Health Promotion (NCCDPHP).   Date Released: 10/17/2012.

  6. Effects of Breath Training Pattern "End-Inspiratory Pause" on Respiratory Mechanics and Arterial Blood Gas of Patients with COPD

    Institute of Scientific and Technical Information of China (English)

    梁永杰; 蔡映云

    2002-01-01

    Objective:In order to explore the mechanism of Chinese traditional breath training, theeffects of end-inspiratory pause breathing (EIPB) on the respiratory mechanics and arterial blood gas werestudied in patients with chronic obstructive pulmonary disease (COPD). Methods: Ten patients in steadystage participating in the study had a breath training of regulating the respiration rhythm as to having apause between the deep and slow inspiration and the slow expiration. Effect of the training was observed byvisual feedback from the screen of the respiratory inductive plethysmograph. The dynamic change of par-tial pressure of oxygen saturation in blood (SpO2) was recorded with sphygmo-oximeter, the pulmonarymechanics and EIPB were determined with spirometer, and the data of arterial blood gases in tranquilizedbreathing and EIPB were analysed. Results: After EIPB training, SpO2 increased progressively, PaO2 in-creased and PaCO2 decreased, and the PaO2 increment was greater than the PaCO2 decrement. Further-more, the tidal volume increased and the frequency of respiration decreased significantly, both inspirationtime and expiration time were prolonged. There was no significant change in both mean inspiration flowrate (VT/Ti) and expiration flow rate (VT/Te). The baselines in spirogram during EIPB training had noraise. Conclusion: EIPB could decrease the ratio of the dead space and tidal volume (VD/VT), cause in-crease of PaO2 more than the decrease of PaCO2, suggesting that this training could improve both the func-tion of ventilation and gaseous exchange in the lung. EIPB training might be a breathing training patternfor rehabilitation of patients with COPD.

  7. Different Bleeding Patterns with the Use of Levonorgestrel Intrauterine System: Are They Associated with Changes in Uterine Artery Blood Flow?

    Directory of Open Access Journals (Sweden)

    Carlo Bastianelli

    2014-01-01

    Full Text Available Objective. Evaluate if different bleeding patterns associated with the use of the levonorgestrel intrauterine system (LNG-IUS are associated with different uterine and endometrial vascularization patterns, as evidenced by ultrasound power Doppler analysis. Methodology. A longitudinal study, with each subject acting as its own control was conducted between January 2010 and December 2012. Healthy volunteers with a history of heavy but cyclic and regular menstrual cycles were enrolled in the study. Ultrasonographic examination was performed before and after six months of LNG-IUS placement: uterine volume, endometrial thickness, and subendometrial and myometrial Doppler blood flow patterns have been evaluated. Results. A total of 32 women were enrolled out of 186 initially screened. At six months of follow-up, all subjects showed a reduction in menstrual blood loss; for analysis, they were retrospectively divided into 3 groups: normal cycling women (Group I, amenorrheic women (Group II, and women with prolonged bleedings (Group III. Intergroup analysis documented a statistically significant difference in endometrial thickness among the three groups; in addition, mean pulsatility index (PI and resistance index (RI in the spiral arteries were significantly lower in Group I and Group III compared to Group II. This difference persisted also when comparing—within subjects of Group III—mean PI and RI mean values before and after insertion. Conclusions. The LNG-IUS not only altered endometrial thickness, but—in women with prolonged bleedings—also significantly changed uterine artery blood flow. Further studies are needed to confirm these results and enable gynecologists to properly counsel women, improving initial continuation rates.

  8. Role of the medulla oblongata in normal and high arterial blood pressure regulation: the contribution of Escola Paulista de Medicina - UNIFESP.

    Science.gov (United States)

    Cravo, Sergio L; Campos, Ruy R; Colombari, Eduardo; Sato, Mônica A; Bergamaschi, Cássia M; Pedrino, Gustavo R; Ferreira-Neto, Marcos L; Lopes, Oswaldo U

    2009-09-01

    Several forms of experimental evidence gathered in the last 37 years have unequivocally established that the medulla oblongata harbors the main neural circuits responsible for generating the vasomotor tone and regulating arterial blood pressure. Our current understanding of this circuitry derives mainly from the studies of Pedro Guertzenstein, a former student who became Professor of Physiology at UNIFESP later, and his colleagues. In this review, we have summarized the main findings as well as our collaboration to a further understanding of the ventrolateral medulla and the control of arterial blood pressure under normal and pathological conditions.

  9. Plasmodium falciparum parasitaemia in the first half of pregnancy, uterine and umbilical artery blood flow, and foetal growth: a longitudinal Doppler ultrasound study

    Directory of Open Access Journals (Sweden)

    Griffin Jennifer B

    2012-09-01

    Full Text Available Abstract Background During early pregnancy, the placenta develops to meet the metabolic demands of the foetus. The objective of this analysis was to examine the effect of malaria parasitaemia prior to 20 weeks’ gestation on subsequent changes in uterine and umbilical artery blood flow and intrauterine growth restriction. Methods Data were analysed from 548 antenatal visits after 20 weeks’ gestation of 128 women, which included foetal biometric measures and interrogation of uterine and umbilical artery blood flow. Linear mixed effect models estimated the effect of early pregnancy malaria parasitaemia on uterine and umbilical artery resistance indices. Log-binomial models with generalized estimating equations estimated the effect of early pregnancy malaria parasitaemia on the risk of intrauterine growth restriction. Results There were differential effects of early pregnancy malaria parasitaemia on uterine artery resistance by nutritional status, with decreased uterine artery resistance among nourished women with early pregnancy malaria and increased uterine artery resistance among undernourished women with early pregnancy malaria. Among primigravidae, early pregnancy malaria parasitaemia decreased umbilical artery resistance in the late third trimester, likely reflecting adaptive villous angiogenesis. In fully adjusted models, primigravidae with early pregnancy malaria parasitaemia had 3.6 times the risk of subsequent intrauterine growth restriction (95% CI: 2.1, 6.2 compared to the referent group of multigravidae with no early pregnancy malaria parasitaemia. Conclusions Early pregnancy malaria parasitaemia affects uterine and umbilical artery blood flow, possibly due to alterations in placentation and angiogenesis, respectively. Among primigravidae, early pregnancy malaria parasitaemia increases the risk of intrauterine growth restriction. The findings support the initiation of malaria parasitaemia prevention and control efforts earlier in

  10. Effects of three days of dry immersion on muscle sympathetic nerve activity and arterial blood pressure in humans.

    Science.gov (United States)

    Iwase, S; Sugiyama, Y; Miwa, C; Kamiya, A; Mano, T; Ohira, Y; Shenkman, B; Egorov, A I; Kozlovskaya, I B

    2000-03-15

    The present study was performed to determine how sympathetic function is altered by simulated microgravity, dry immersion for 3 days, and to elucidate the mechanism of post-spaceflight orthostatic intolerance in humans. Six healthy men aged 21-36 years old participated in the study. Before and after the dry immersion, subjects performed head-up tilt (HUT) test to 30 degrees and 60 degrees (5 min each) with recordings of muscle sympathetic nerve activity (MSNA, by microneurography), electrocardiogram, and arterial blood pressure (Finapres). Resting MSNA was increased after dry immersion from 23.7+/-3.2 to 40.9+/-3.0 bursts/min (p<0.005) without significant changes in resting heart rate (HR). MSNA responsiveness to orthostasis showed no significant difference but HR response was significantly augmented after dry immersion (p<0. 005). A significant diastolic blood pressure fall at 5th min of 60 degrees HUT was observed in five orthostatic tolerant subjects despite enough MSNA discharge after dry immersion. A subject suffered from presyncope at 2 min after 60 degrees HUT. He showed gradual blood pressure fall 10 s after 60 degrees HUT with initially well-maintained MSNA response and then with a gradually attenuated MSNA, followed by a sudden MSNA withdrawal and abrupt blood pressure drop. In conclusion, dry immersion increased MSNA without changing MSNA response to orthostasis, and resting HR, while increasing the HR response to orthostasis. Analyses of MSNA and blood pressure changes in orthostatic tolerant subjects and a subject with presyncope suggested that not only insufficient vasoconstriction to sympathetic stimuli, but also a central mechanism to induce a sympathetic withdrawal might play a role in the development of orthostatic intolerance after microgravity exposure.

  11. Biochemical characterization of blood plasma of coronary artery disease patients by in vitro high-resolution proton NMR spectroscopy

    Indian Academy of Sciences (India)

    Anu Malik; Uma Sharma; R Lakshmy; Rajiv Narang; Naranamanglam R Jagannathan

    2015-03-01

    This study aimed to investigate the biochemical profile of blood plasma of patients with coronary artery disease (CAD) and angiographically normal subjects (controls) to determine biomarkers for their differentiation. In this double blind study, 5 mL venous blood was drawn before angiography from CAD patients (n=60) and controls (n=13) comprising angiography normal individuals. In vitro high-resolution NMR spectroscopy of these blood plasma samples was carried out at 400 MHz, and intensity data were analysed with partial least square discriminant analysis. Categorization of subjects as controls or CAD patients and the patients further as single vessel disease (SVD), double vessel disease (DVD) and triple vessel disease (TVD) was done at the end of the study based on their angiography reports. Raised levels of lipids, alanine (Ala) and isoleucine/leucine/valine (Ile/Leu/Val) were observed in CAD patients compared with controls. Partial least square discriminant analysis showed separation between controls vs CAD patients. TVD patients showed increased levels of Ile/Leu/Val and Ala compared with controls and SVD. Alanine, Ile/Leu/Val, and LDL/VLDL appear as possible biomarkers for distinguishing between controls and patients with SVD and TVD. A metabolic adaptation of myocardium may play a role in raising the Ala level.

  12. The reproducibility of cerebral blood flow with N-isopropyl-p-({sup 123}I) iodoamphetamine by arterial blood sampling method

    Energy Technology Data Exchange (ETDEWEB)

    Sasaki, Kazufumi; Tamura, Kiyohiko [Akita Univ. (Japan). Hospital; Hirano, Hiroko; Oyama, Yoichi; Kobayashi, Mitsuru; Tomura, Noriaki; Watari, Jiro

    1997-12-01

    The reproducibility of cerebral blood flow (CBF) based on the microsphere model with N-isopropyl-p-({sup 123}I) iodoamphetamine (IMP), was evaluated 4.58% (=CV) and was within 9%. The former was calculated from the elementary experiments, the latter was calculated with the CBF of 11 cases. On the clinical conditions, where we selected some astrocytomas of grade III injected ACNU super selectively with Seldinger catheter, and quantified CBF both pre and post ACNU ia by the ROI of 16.2 mm{phi}. On the other hand we have been monitoring the Cross Calibration Factors (CCFs) since we started CBF quantification. The CCFs during 5 years were all within the upper and the lower control limits. At a worst case the average deviation of CCF was 1.17% by a month, which is equal to 7.0% by 6 months. Then SPECT and well counter should be calibrated at least once every 6 months. (author)

  13. Blood flow of Jeffrey fluid in a catherized tapered artery with the suspension of nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Ellahi, R., E-mail: rellahi@engr.ucr.edu [Department of Mechanical Engineering, University of California Riverside (United States); Department of Mathematics and Statistics, FBAS, IIU, Islamabad (Pakistan); Rahman, S.U. [Department of Mathematics and Statistics, FBAS, IIU, Islamabad (Pakistan); Nadeem, S. [Department of Mathematics, Quaid-i-Azam University Islamabad (Pakistan)

    2014-08-14

    Current letter deals with the mathematical models of Jeffrey fluid via nanoparticles in the tapered stenosed atherosclerotic arteries. The convection effects of heat transfer with catheter are also taken into account. The nonlinear coupled equations of nanofluid model are simplified under mild stenosis. The solutions for concentration and temperature are found by using homotopy perturbation method, whereas for velocity profile the exact solution is calculated. Moreover, the expressions for flow impedance and pressure rise are computed and discussed through graphs for different physical quantities of interest. The streamlines have also been presented to discuss the trapping bolus discipline.

  14. Blood flow of Jeffrey fluid in a catherized tapered artery with the suspension of nanoparticles

    Science.gov (United States)

    Ellahi, R.; Rahman, S. U.; Nadeem, S.

    2014-08-01

    Current letter deals with the mathematical models of Jeffrey fluid via nanoparticles in the tapered stenosed atherosclerotic arteries. The convection effects of heat transfer with catheter are also taken into account. The nonlinear coupled equations of nanofluid model are simplified under mild stenosis. The solutions for concentration and temperature are found by using homotopy perturbation method, whereas for velocity profile the exact solution is calculated. Moreover, the expressions for flow impedance and pressure rise are computed and discussed through graphs for different physical quantities of interest. The streamlines have also been presented to discuss the trapping bolus discipline.

  15. Modelling of the dynamic relationship between arterial pressure, renal sympathetic nerve activity and renal blood flow in conscious rabbits.

    Science.gov (United States)

    Berger, C S; Malpas, S C

    1998-12-01

    A linear autoregressive/moving-average model was developed to describe the dynamic relationship between mean arterial pressure (MAP), renal sympathetic nerve activity (SNA) and renal blood flow (RBF) in conscious rabbits. The RBF and SNA to the same kidney were measured under resting conditions in a group of eight rabbits. Spectral analysis of the data sampled at 0.4 Hz showed that the low-pass bandwidth of the signal power for RBF was approximately 0. 05 Hz. An autoregressive/moving-average model with an exogenous input (ARMAX) was then derived (using the iterative Gauss-Newton algorithm provided by the MATLAB identification Toolbox), with MAP and SNA as inputs and RBF as output, to model the low-frequency fluctuations. The model step responses of RBF to changes in SNA and arterial pressure indicated an overdamped response with a settling time that was usually less than 2 s. Calculated residuals from the model indicated that 79 5 % (mean s.d., averaged over eight independent experiments) of the variation in RBF could be accounted for by the variations in arterial pressure and SNA. Two additional single-input models for each of the inputs were similarly obtained and showed conclusively that changes in RBF, in the conscious resting rabbit, are a function of both SNA and MAP and that the SNA signal has the predominant effect. These results indicate a strong reliance on SNA for the dynamic regulation of RBF. Such information is likely to be important in understanding the diminished renal function that occurs in a variety of disease conditions in which overactivity of the sympathetic nervous system occurs.

  16. Multi-scale finite element analyses for stress and strain evaluations of braid fibril artificial blood vessel and smooth muscle cell.

    Science.gov (United States)

    Nakamachi, Eiji; Uchida, Takahiro; Kuramae, Hiroyuki; Morita, Yusuke

    2014-08-01

    In this study, we developed a multi-scale finite element (FE) analysis code to obtain the stress and strain that occurred in the smooth muscle cell (SMC) at micro-scale, which was seeded in the real fabricated braid fibril artificial blood vessel. This FE code can predict the dynamic response of stress under the blood pressure loading. We try to establish a computer-aided engineering (CAE)-driven scaffold design technique for the blood vessel regeneration. Until now, there occurred the great progresses for the endothelial cell activation and intima layer regeneration in the blood vessel regeneration study. However, there remains the difficulty of the SMC activation and media layer regeneration. Therefore, many researchers are now studying to elucidate the fundamental mechanism of SMC activation and media layer regeneration by using the biomechanical technique. As the numerical tool, we used the dynamic-explicit FE code PAM-CRASH, ESI Ltd. For the material models, the nonlinear viscoelastic constitutive law was adapted for the human blood vessel, SMC and the extra-cellular matrix, and the elastic law for the polyglycolic acid (PGA) fiber. Through macro-FE and micro-FE analyses of fabricated braid fibril tubes by using PGA fiber under the combined conditions of the orientation angle and the pitch of fiber, we searched an appropriate structure for the stress stimulation for SMC functionalization. Objectives of this study are indicated as follows: 1. to analyze the stress and strain of the human blood vessel and SMC, and 2. to calculate stress and strain of the real fabricated braid fibril artificial blood vessel and SMC to search an appropriate PGA fiber structure under combined conditions of PGA fiber numbers, 12 and 24, and the helical orientation angles of fiber, 15, 30, 45, 60, and 75 degrees. Finally, we found a braid fibril tube, which has an angle of 15 degree and 12 PGA fibers, as a most appropriate artificial blood vessel for SMC functionalization.

  17. Preliminary study of abnormal increase of postexercise systolic blood pressure in the diagnosis of coronary artery disease

    Institute of Scientific and Technical Information of China (English)

    于宗良; 杨向军; 王国强; 高美雯; 李勋; 惠杰; 蒋廷波; 宋建平; 刘志华; 蒋文平

    2003-01-01

    Objectives This study sought to evaluate the diagnostic value of abnormal increase of postexercise systolic blood pressure (SBP) for detecting coronary artery disease (CAD) in patients with or without hypertension. Methods Treadmill exercise testing (TET) was conducted in 88 patients (40 CAD patients, 48 control subjects)with or without hypertension, each of whom underwent selective coronary angiography (CAG). The abnormal increase of postexercise SBP was defined as 10mmHg higher than earlier periods during the recovery phase (6 minutes)of exercise testing. Results The abnormal increase of postexercise SBP had higher sensitivity, specificity,and accuracy for detecting CAD than those of ST - segment depression in patients with or without hypertension. Its accuracy increased with the severity of CAD while decreased in patients with hypertension, and the increase value of SBP had a positive correlation with the extent of coronary artery lesion. The combination of ST - segment depression and abnormal increase of postexercise SBP diagnosed CAD most accurately in patients with hypertension. Conclusions Abnormal increase of postexercise SBP may be a useful index for diagnosing CAD.

  18. Cerebral Blood Flow Measured by Arterial Spin Labeling MRI as a Preclinical Marker of Alzheimer’s Disease

    Science.gov (United States)

    Wierenga, Christina E.; Hays, Chelsea C.; Zlatar, Zvinka Z.

    2017-01-01

    There is growing recognition that cerebral hypoperfusion is related to the pathogenesis of Alzheimer’s disease (AD), implicating the measurement of cerebral blood flow (CBF) as a possible biomarker of AD. The ability to identify the earliest and most reliable markers of incipient cognitive decline and clinical symptoms is critical to develop effective preventive strategies and interventions for AD. Arterial spin labeling (ASL) magnetic resonance imaging (MRI) measures CBF by magnetically labeling arterial water and using it as an endogenous tracer. Studies using ASL MRI in humans indicate that CBF changes are present several years before the development of the clinical symptoms of AD. Moreover, ASL-measured CBF has been shown to distinguish between cognitively normal individuals, adults at risk for AD, and persons diagnosed with AD. Some studies indicate that CBF may even be sensitive for predicting cognitive decline and conversion to mild cognitive impairment and AD over time. Taken together, evidence suggests that the current staging models of AD biomarker pathology should incorporate early changes in CBF as a useful biomarker, possibly present even earlier than amyloid β accumulation. Though still a research tool, ASL imaging is a promising non-invasive and reliable method with the potential to serve as a future clinical tool for the measurement of CBF in preclinical AD. PMID:25159672

  19. Predictive Factors of Arterial Blood Oxygen Desaturation During Upper Gastrointestinal Endoscopy in Nonsedated Patients

    Directory of Open Access Journals (Sweden)

    O Alimardani

    2008-10-01

    Full Text Available Introduction: Hypoxemia can occur during upper gastrointestinal endoscopy with or without pharmacological sedation. Pulse oximetry saturation (SpO2 levels were assessed in patients attending for routine unsedated diagnostic upper gastrointestinal endoscopy to identify factors associated with oxygen desaturation. Methods: A total of 300 patients who underwent upper gastrointestinal endoscopy without sedation were monitored with continuous pulse oximetry. Factors related to the patient, the examination, and the monitoring data that could predict severe desaturation were evaluated. Results: Mild desaturation (SpO2 between 1-4% was found in 143(47.7% of the patients, while severe desaturation (SpO2≥5% and hypoxemia occurred in 65 (21.7% of patients, 40 (61.5% of those had previous illnesses (p<0.001. The variables found to predict severe desaturation were basal SpO2 <95%, chronic obstructive pulmonary disease, anemia, age more than 60 years and coronary artery disease. Conclusion: The decrease in SpO2 is related to increase in age, basal SaO2 < 95%, respiratory disease, coronary artery disease, and anemia, .We recommend continuous monitoring of SpO2 in these high-risk patients undergoing upper gastrointestinal endoscopy.

  20. Differential Telomere Shortening in Blood versus Arteries in an Animal Model of Type 2 Diabetes

    Directory of Open Access Journals (Sweden)

    Samira Tajbakhsh

    2015-01-01

    Full Text Available Vascular dysfunction is an early feature of diabetic vascular disease, due to increased oxidative stress and reduced nitric oxide (NO bioavailability. This can lead to endothelial cell senescence and clinical complications such as stroke. Cells can become senescent by shortened telomeres and oxidative stress is known to accelerate telomere attrition. Sirtuin 1 (SIRT1 has been linked to vascular health by upregulating endothelial nitric oxide synthase (eNOS, suppressing oxidative stress, and attenuating telomere shortening. Accelerated leukocyte telomere attrition appears to be a feature of clinical type 2 diabetes (T2D and therefore the telomere system may be a potential therapeutic target in preventing vascular complications of T2D. However the effect of T2D on vascular telomere length is currently unknown. We hypothesized that T2D gives rise to shortened leukocyte and vascular telomeres alongside reduced vascular SIRT1 expression and increased oxidative stress. Accelerated telomere attrition was observed in circulating leukocytes, but not arteries, in T2D compared to control rats. T2D rats had blunted arterial SIRT1 and eNOS protein expression levels which were associated with reduced antioxidant defense capacity. Our findings suggest that hyperglycemia and a deficit in vascular SIRT1 per se are not sufficient to prematurely shorten vascular telomeres.

  1. Influence of a history of arterial hypertension and pretreatment blood pressure on the effect of angiotensin converting enzyme inhibition after acute myocardial infarction. Trandolapril Cardiac Evaluation Study

    DEFF Research Database (Denmark)

    Gustafsson, F; Køber, L; Torp-Pedersen, C

    1998-01-01

    inhibition after AMI complicated by left ventricular dysfunction may be of particular importance in patients with a history of arterial hypertension or a relatively high pretreatment blood pressure. However, further investigations are necessary to establish the clinical impact of these results.......OBJECTIVE: To evaluate the influence of a history of arterial hypertension and the level of pretreatment blood pressure on the efficacy of the angiotensin converting enzyme (ACE) inhibitor trandolapril on mortality and morbidity in patients with acute myocardial infarction (AMI) and left...... for a broad spectrum of potential confounders. Also, benefit from ACE inhibition increased with increasing blood pressure at the time of randomization. Significant interactions between benefit from ACE inhibition and hypertension history, and systolic and diastolic blood pressure were found. CONCLUSION: ACE...

  2. Feasibility of measuring superior mesenteric artery blood flow during cardiac surgery under hypothermic cardiopulmonary bypass using transesophageal echocardiography: An observational study

    Directory of Open Access Journals (Sweden)

    Naveen G Singh

    2016-01-01

    Full Text Available Background: Abdominal complications being rare but results in high mortality, commonly due to splanchnic organ hypoperfusion during the perioperative period of cardiac surgery. There are no feasible methods to monitor intraoperative superior mesenteric artery blood flow (SMABF. Hence, the aim of this study was to evaluate the feasibility and to measure SMABF using transesophageal echocardiography (TEE during cardiac surgery under hypothermic cardiopulmonary bypass (CPB. Methodology: Thirty-five patients undergoing elective cardiac surgery under CPB were enrolled. Heart rate, mean arterial pressure (MAP, cardiac output (CO, SMABF, superior mesenteric artery (SMA diameter, superior mesentric artery blood flow over cardiac output (SMA/CO ratio and arterial blood lactates were recorded at three time intervals. T0: before sternotomy, T1: 30 min after initiation of CPB and T2: after sternal closure. Results: SMA was demonstrated in 32 patients. SMABF, SMA diameter, SMA/CO, MAP and CO-decreased significantly (P 0.05 between T0 and T2. Lactates increased progressively from T0 to T2. Conclusion: Study shows that there is decrease in SMABF during CPB and returns to baseline after CPB. Hence, it is feasible to measure SMABF using TEE in patients undergoing cardiac surgery under hypothermic CPB. TEE can be a promising tool in detecting and preventing splanchnic hypoperfusion during perioperative period.

  3. Blood and urine levels of heavy metal pollutants in female and male patients with coronary artery disease

    Directory of Open Access Journals (Sweden)

    Sponder M

    2014-05-01

    Full Text Available Michael Sponder,1 Monika Fritzer-Szekeres,2 Rodrig Marculescu,2 Martina Mittlböck,3 Maria Uhl,4 Birgit Köhler-Vallant,5 Jeanette Strametz-Juranek1 1Department of Cardiology, Medical University of Vienna, Vienna, Austria; 2Department of Medical-Chemical Laboratory Analysis, Medical University of Vienna, Vienna, Austria; 3Department of Medical Statistics, Informatics and Intelligent Systems, Section for Clinical Biometrics, Medical University of Vienna, Vienna, Austria; 4Department of Pollutants and Human, Environment Agency Austria, Vienna, Austria; 5Department of Inorganic Analysis, Environment Agency Austria, Vienna, Austria Background: Heavy metal pollutants such as cadmium (Cd, lead (Pb, and mercury (Hg are rarely the subjects of cardiovascular research although they have been suspected for decades to negatively impact the circulatory system. Methods: Apart from detailed anamnestic data, urinary levels of Cd and full blood levels of Pb and Hg were measured in 53 female (mean age: 68.04±7.03 years and 111 male (mean age: 60.68±11.43 years nonsmoking or never-smoking patients with angiographically verified and precisely quantified coronary artery disease (CAD. Results: Although Cd was quantifiable in 68.3% of subjects, only 34.1% of these patients exceeded the critical 1 µg/L Human Biomonitoring (HBM-I level. Median Pb (20 µg/L and Hg (0.55 µg/L levels were lower than the HBM-I, as well as reference levels of Pb. Wine consumption was the main source for Pb, fish and wine consumption for Hg, and previous nicotine abuse for Cd. There was no correlation between Cd, Pb, or Hg and severity of CAD although severity correlated positively with atherosclerosis parameters (uric acid, creatinine, triglycerides, blood urea nitrogen, C-reactive protein and negatively with high density lipoprotein cholesterol. Conclusion: Cd levels detected in CAD patients were high compared to German and European reference levels but it could not be proven that urine

  4. The effects of venous cannulation technique and cardioplegia type on plasma potassium concentration and arterial blood pressure during cardiopulmonary bypass.

    LENUS (Irish Health Repository)

    Coleman, E T

    2012-02-03

    The cannulation method and cardioplegia solution used during cardiopulmonary bypass (CPB) may both influence plasma potassium concentrations ([K+]) and mean arterial blood pressure (MAP). Bi-caval or right atrial cannulation methods are routinely used in conjunction with crystalloid or blood cardioplegia. We investigated the influence of cannulation method and cardioplegia solutions on plasma [K+] and MAP during cardiopulmonary bypass. Sixty consecutive patients undergoing elective coronary artery bypass grafting (CABG) using CPB were studied. They were randomly divided into three groups of 20 patients. Patients in Group A underwent bi-caval venous cannulation and received crystalloid cardioplegia. Group B patients underwent right atrial cannulation and received crystalloid cardioplegia. Group C patients underwent right atrial cannulation and received blood cardioplegia. In each case. cardioplegia was administered antegrade via the aortic root. Plasma [K+], MAP. and hemoglobin concentration (Hb) were measured over an 8-min period following cardioplegia administration (pilot studies indicated pressure changes occuring post cardioplegia administration up to this time). The combination of bi-caval cannulation and crystalloid cardioplegia (Group A) was associated with the least increase in plasma [K+] and no decrease in MAP. The maximum [K+] for this Group was 4.2 mmol\\/L (4.6% increase). The minimum mean pressure was 57 mmHg (13.6% increase). Both right atrial cannulation groups (B and C) showed a large rise in plasma [K+] and a decrease in MAP. Group B maximum [K+] was 5.2 mmol\\/L (27.5% increase). Group C was also 5.2 mmol\\/L (26.0% increase). Group C showed the largest pressure decrease, the minimum mean pressure was 45 mmHg (21.3% decrease). The Group B minimum mean pressure was 45 mmHg (8.7% decrease). Our results show that patients undergoing CPB operations who are deemed to be at increased risk of suffering adverse effects from hypotensive episodes may

  5. Influence of Blood Inertia on Vortex Enhancement in the Wake of Plaque Deposited Arteries

    Directory of Open Access Journals (Sweden)

    Muhammad Anwar Solangi

    2011-04-01

    Full Text Available Flow of blood structure is presented in terms of stream line projections at different percentages of deposition against various Reynolds numbers. The impact of atherosclerosis is investigated on the vortex enhancement and intensity. The predicted results are computed in terms of stream function for quantifying the reattachment length and re-circulating flow rate of blood at various Reynolds numbers and different percentages of blockage. The results show that flow of blood is disturbs at the vicinity of blockage, especially in the down stream area that leads to the formation of vortexes. It is observed that the length of vortex increases along with the deposition levels as well as with increasing inertia .To solve the Navier-Stokes equations, together with the incompressibility constraints a semi-implicit time stepping procedure, namely Taylor- Galerkin/Pressure-correction finite element scheme has been employed.

  6. Quadruple-component superficial circumflex iliac artery perforator (SCIP) flap: A chimeric SCIP flap for complex ankle reconstruction of an exposed artificial joint after total ankle arthroplasty.

    Science.gov (United States)

    Yamamoto, Takumi; Saito, Takafumi; Ishiura, Ryohei; Iida, Takuya

    2016-09-01

    Total ankle arthroplasty (TAA) is becoming popular in patients with rheumatoid arthritis (RA)-associated ankle joint degeneration. However, ankle wound complications can occur after TAA, which sometimes requires challenging reconstruction due to anatomical complexity of the ankle. Superficial circumflex iliac artery (SCIA) perforator (SCIP) flap has been reported to be useful for various reconstructions, but no case has been reported regarding a chimeric SCIP flap for complex ankle reconstruction. We report a case of complex ankle defect successfully reconstructed with a free quadruple-component chimeric SCIP flap. A 73-year-old female patient with RA underwent TAA, and suffered from an extensive ankle soft tissue defect (13 × 5 cm) with exposure of the implanted artificial joint and the extensor tendons. A chimeric SCIP flap was raised based on the deep branch and the superficial branch of the SCIA, which included chimeric portions of the sartorius muscle, the deep fascia, the inguinal lymph node (ILN), and the skin/fat. The flap was transferred to the recipient ankle. The sartorius muscle was used to cover the artificial joint, the deep fascia to reconstruct the extensor retinaculum, the ILN to prevent postoperative lymphedema, and the adiposal tissue to put around the extensor tendons for prevention of postoperative adhesion. Postoperatively, the patient could walk by herself without persistent leg edema or bowstringing of the extensor tendons, and was satisfied with the concealable donor scar. Although further studies are required to confirm efficacy, multicomponent chimeric SCIP has a potential to be a useful option for complex defects of the ankle.

  7. Blood Glucose Prediction Using Artificial Neural Networks Trained with the AIDA Diabetes Simulator: A Proof-of-Concept Pilot Study

    Directory of Open Access Journals (Sweden)

    Gavin Robertson

    2011-01-01

    Full Text Available Diabetes mellitus is a major, and increasing, global problem. However, it has been shown that, through good management of blood glucose levels (BGLs, the associated and costly complications can be reduced significantly. In this pilot study, Elman recurrent artificial neural networks (ANNs were used to make BGL predictions based on a history of BGLs, meal intake, and insulin injections. Twenty-eight datasets (from a single case scenario were compiled from the freeware mathematical diabetes simulator, AIDA. It was found that the most accurate predictions were made during the nocturnal period of the 24 hour daily cycle. The accuracy of the nocturnal predictions was measured as the root mean square error over five test days (RMSE5 day not used during ANN training. For BGL predictions of up to 1 hour a RMSE5 day of (±SD 0.15±0.04 mmol/L was observed. For BGL predictions up to 10 hours, a RMSE5  day of (±SD 0.14±0.16 mmol/L was observed. Future research will investigate a wider range of AIDA case scenarios, real-patient data, and data relating to other factors influencing BGLs. ANN paradigms based on real-time recurrent learning will also be explored to accommodate dynamic physiology in diabetes.

  8. Glytube: a conical tube and parafilm M-based method as a simplified device to artificially blood-feed the dengue vector mosquito, Aedes aegypti.

    Directory of Open Access Journals (Sweden)

    André Luis Costa-da-Silva

    Full Text Available Aedes aegypti, the main vector of dengue virus, requires a blood meal to produce eggs. Although live animals are still the main blood source for laboratory colonies, many artificial feeders are available. These feeders are also the best method for experimental oral infection of Ae. aegypti with Dengue viruses. However, most of them are expensive or laborious to construct. Based on principle of Rutledge-type feeder, a conventional conical tube, glycerol and Parafilm-M were used to develop a simple in-house feeder device. The blood feeding efficiency of this apparatus was compared to a live blood source, mice, and no significant differences (p = 0.1189 were observed between artificial-fed (51.3% of engorgement and mice-fed groups (40.6%. Thus, an easy to assemble and cost-effective artificial feeder, designated "Glytube" was developed in this report. This simple and efficient feeding device can be built with common laboratory materials for research on Ae. aegypti.

  9. Arterial pressure variations as parameters of brain perfusion in response to central blood volume depletion and repletion

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    Anne-Sophie G.T. Bronzwaer

    2014-04-01

    Full Text Available Rationale:A critical reduction in central blood volume (CBV is often characterized by hemodynamic instability. Restoration of a volume deficit may be established by goal-directed fluid therapy guided by respiration-related variation in systolic- and pulse pressure (SPV and PPV. Stroke volume index (SVI serves as a surrogate end-point of a fluid challenge but tissue perfusion itself has not been addressed. Objective: To delineate the relationship between arterial pressure variations, SVI and regional brain perfusion during CBV depletion and repletion in spontaneously breathing volunteers. Methods: This study quantified in 14 healthy subjects (11 male the effects of CBV depletion (by 30 and 70 degrees passive head-up tilt (HUT and a fluid challenge (by tilt back on CBV (thoracic admittance, mean middle cerebral artery (MCA blood flow velocity (Vmean, SVI, cardiac index (CI , PPV and SPV. Results: PPV (103±89%, p< 0.05 and SPV (136±117%, p< 0.05 increased with progression of central hypovolemia manifested by a reduction in thoracic admittance (11±5%, p< 0.001, SVI (28±6%, p< 0.001, CI (6±8%, p< 0.001 and MCAVmean (17±7%, p< 0.05 but not in arterial pressure. The reduction in MCAVmean correlated to the fall in SVI (R2=0.52, p< 0.0001 and inversely to PPV and SPV (R2=0.46 (p< 0.0001 and R2=0.45 (p< 0.0001, respectively. PPV and SPV predicted a ≥15% reduction in MCAVmean and SVI with comparable sensitivity (67%/ 67% vs. 63%/ 68% respectively and specificity (89%/94% vs. 89%/94%, respectively. A rapid fluid challenge by tilt-back restored all parameters to baseline values within one minute. Conclusion: In spontaneously breathing subjects, a reduction in MCAVmean was related to an increase in PPV and SPV during graded CBV depletion and repletion. Specifically, PPV and SPV predicted changes in both SVI and MCAVmean with comparable sensitivity and specificity, however the predictive value is limited in spontaneously breathing subjects.

  10. [Influence of treatment with olmesartan on ambulatory blood pressure monitoring parameters in patients with arterial hypertension].

    Science.gov (United States)

    Bregvadze, T R; Tseluĭko, V I; Mishchuk, N E

    2013-12-01

    Hypertension is the most common disease of the cardiovascular system. Active treatment of hypertension with adequate control of blood pressure (BP) can prevent complications, improve life quality and increase life expectancy. One of the interesting new antihypertensive agents, from the group of angiotensin receptor blockers is olmesartan. The obvious advantages of ambulatory blood pressure monitoring to traditional one-time measurements of BP make this method perspective for quality control of anti-hypertensive therapy. The aim of this study was to evaluate the influence of treatment with olmesartan on ambulatory blood pressure monitoring parameters in patients with hypertension. 38 out-patients with hypertension at the age of 25-84 years (mean 55,3±10,6) were studied. Patients received olmesartan 20 mg daily as monotherapy (20 patients (52,6%)) or in combination with other antihypertensive agents (18 patients (47,4%)). Treatment continued for 6 months. The complex examination included: measurement of office brachial BP, electrocardiography, echocardiography and ambulatory blood pressure monitoring (ABPM). As a result of treatment, office BP and diurnal BP, according to ABPM, significantly decreased; the favorable circadian BP profile dynamics were found: significantly less frequently observed lack of reduction in BP during night (daily index - non-dipper) - 18% vs. 64% (p treatment of hypertensive patients with olmesartan provides significant decline not only in office BP, but also in diurnal BP, normalizes BP of active and passive periods, also - daily index and reduces BP variability.

  11. Small artery structure adapts to vasodilatation rather than to blood pressure during antihypertensive treatment

    DEFF Research Database (Denmark)

    2007-01-01

    . RESULTS: In group A, mean ambulatory blood pressure (ABP) fell from 119 +/- 2 (SE) to 103 +/- 2 mmHg (P 1 to 99 +/- 1 mmHg, P = NS). Both groups showed similar reductions in Rrest (-33.4 and -28.5%, respectively) and in Rmin (-15.4 and -15...

  12. Numerical analysis of blood flow in realistic arteries subjected to strong non-uniform magnetic fields

    NARCIS (Netherlands)

    Kenjeres, S.

    2008-01-01

    The paper reports on a comprehensive mathematical model for simulations of blood flow under the presence of strong non-uniform magnetic fields. The model consists of a set of Navier–Stokes equations accounting for the Lorentz and magnetisation forces, and a simplified set of Maxwell’s equations (Bio

  13. A Novel System for Measuring Optical Properties in Arterial Blood of Man

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    A. Castañeda-Miranda

    2006-01-01

    Full Text Available The necessity of man–machine communication has been increasing day by day because of the great number of approaches that help to make human life agile or comfortable. Health is one of the aspects that has generated more interest in recent years. The optical technologies are new technical tools that are being implemented for medical diagnosis and for describing various processes occurring within human blood. These techniques have the virtue of being nondestructive; in addition they have the advantage of remote direction by using an in situ technique, with sensitivity capable of studying the properties of the blood through electromagnetic excitation. A device to obtain the electromagnetic spectrum in the blood has being designed and is presented in this work. This device uses a quartz lamp, emitting electromagnetic radiation between 200 nm and 2200 nm. A model for measuring the light attenuation through the blood is used. By applying a control in the frequency domain, a circuit device is designed. This device uses a database in time domain for its subsequent analysis by Fast Fourier Transformation in order to obtain absorption spectra. The acquisition time is of the order of microseconds, and the system is controlled automatically through accessible software from a personal computer.

  14. Level-Set Based Artery-Vein Separation in Blood Pool Agent CE-MR Angiograms

    NARCIS (Netherlands)

    Bemmel, van C.M.; Spreeuwers, L.J.; Viergever, M.A.; Niessen, W.J.

    2003-01-01

    Blood pool agents (BPAs) for contrast-enhanced (CE) magnetic-resonance angiography (MRA) allow prolonged imaging times for higher contrast and resolution. Imaging is performed during the steady state when the contrast agent is distributed through the complete vascular system. However, simultaneous v

  15. Intraoperative vascular anatomy, arterial blood flow velocity, and microcirculation in unilateral and bilateral cleft lip repair

    NARCIS (Netherlands)

    Mueller, A.A.; Schumann, D.; Reddy, R.R.; Schwenzer-Zimmerer, K.; Mueller-Gerbl, M.; Zeilhofer, H.F.; Sailer, H.F.; Reddy, S.G.

    2012-01-01

    BACKGROUND: Cleft lip repair aims to normalize the disturbed anatomy and function. The authors determined whether normalization of blood circulation is achieved. METHODS: The authors measured the microcirculatory flow, oxygen saturation, and hemoglobin level in the lip and nose of controls (n = 22)

  16. Magnetic characterization of human blood in the atherosclerotic process in coronary arteries

    Energy Technology Data Exchange (ETDEWEB)

    Janus, B. [Institute of Environmental Engineering PAS, ul. SkLodowskiej-Curie 34, 41-819 Zabrze (Poland); Bucko, M.S., E-mail: michal.bucko@helsinki.f [Institute of Environmental Engineering PAS, ul. SkLodowskiej-Curie 34, 41-819 Zabrze (Poland); Division of Geophysics and Astronomy, P.O. Box 64, Gustaf Haellstroemin katu 2, 00014 University of Helsinki (Finland); Chrobak, A. [University of Silesia, Institute of Physics, ul. Uniwersytecka 4, 40-007 Katowice (Poland); Wasilewski, J. [3rd Chair and Clinical Ward of Cardiology, Medical University of Silesia, Katowice, Silesian Centre of Heart Diseases, ul. Szpitalna 2, 41-800 Zabrze (Poland); Zych, M. [Department of Pharmacognosy and Phytochemistry, Medical University of Silesia, ul. Jagiellonska 4, 41-200 Sosnowiec (Poland)

    2011-03-15

    In the last decades there has been an increasing interest in biomagnetism-a field of biophysics concerned with the magnetic properties of living organisms. Biomagnetism focuses on the measurement of magnetic properties of biological samples in the clinical environment. Progress in this field can provide new data for the understanding of the pathomechanism of atherosclerosis and support the diagnostic options for the evaluation and treatment of atherothrombotic complications. Lyophilized human blood samples from patients with atherosclerotic lesions (calcium scoring (CS) CS>0) and without atherosclerotic lesions (CS=0) were magnetically investigated. Magnetic measurements (performed in room and low temperature) indicated significant magnetic differences between these two groups of patients. Atherosclerotic blood samples are characterized by higher concentration of ferrimagnetic particles (magnetite and/or maghemite) and significant changes in the superparamagnetic behaviour. This research presents that magnetometry, in combination with medical research can lead to a better understanding of iron physiology in the atherosclerotic process. - Research Highlights: {yields}Blood samples are characterized by higher concentration of ferrimagnetic particles. {yields}Atherosclerotic blood samples consist of larger superparamagnetic clusters. {yields}Superparamagnetic particles in pathological samples are considered to be magnetite. {yields}The formation of ferrimagnetic particles is favoured in the atherosclerotic patients. {yields}Magnetite may play a role in the progression of atherosclerosis.

  17. Simulation of Blood Flow Coronary Artery with Consecutive Stenosis and Coronary-Coronary Bypass

    Directory of Open Access Journals (Sweden)

    Omid Arjmandi-Tash

    2011-08-01

    Full Text Available Introduction: In this research the behavior of coronary arteries has been studied with symmetric and asymmetric consecutive stenosis, and grafted vessels. Methods: The incompressible Navier-Stokes and energy equations were discretized with second-order upwind method. Assumptions such as Newtonian fluid, wall rigidity and steady-flow were used. Results: All the calculations showed the same results with Newtonians and non-Newtonian fluids. It was found that the possibility of stenosis be reduced by increasing the graft angle. However, there exists further stenosis possibility. Among the three graft angles 20, 30 ̊ and 40, the 30 ̊ was found to be the reliable ones. Conclusion: Based on these findings, it can be deduced that there would be a high risk of further atherosclerosis when the first stenose has the maximum percentage.

  18. In vivo measurement of intracellular pH in human brain during different tensions of carbon dioxide in arterial blood. A 31P-NMR study

    DEFF Research Database (Denmark)

    Jensen, K E; Thomsen, C; Henriksen, O

    1988-01-01

    The effect of changes in carbon dioxide tension in arterial blood upon intracellular pH in brain tissue was studied in seven healthy volunteers, aged 22-45 years. The pH changes were monitored by use of 31P nuclear magnetic resonance spectroscopy, performed on a whole-body 1.5 Tesla Siemens imaging...

  19. Angioplasty and stenting for severe vertebral artery oriifce stenosis:effects on cerebellar function remodeling veriifed by blood oxygen level-dependent functional magnetic resonance imaging

    Institute of Scientific and Technical Information of China (English)

    Bo Liu; Zhiwei Li; Peng Xie

    2014-01-01

    Vertebral artery oriifce stenting may improve blood supply of the posterior circulation of the brain to regions such as the cerebellum and brainstem. However, previous studies have mainly focused on recovery of cerebral blood lfow and perfusion in the posterior circulation after inter-ventional therapy. This study examined the effects of functional recovery of local brain tissue on cerebellar function remodeling using blood oxygen level-dependent functional magnetic reso-nance imaging before and after interventional therapy. A total of 40 Chinese patients with severe unilateral vertebral artery oriifce stenosis were enrolled in this study. Patients were equally and randomly assigned to intervention and control groups. The control group received drug treat-ment only. The intervention group received vertebral artery oriifce angioplasty and stenting+identical drug treatment to the control group. At 13 days after treatment, the Dizziness Handicap Inventory score was compared between the intervention and control groups. Cerebellar function remodeling was observed between the two groups using blood oxygen level-dependent function-al magnetic resonance imaging. The improvement in dizziness handicap and cerebellar function was more obvious in the intervention group than in the control group. Interventional therapy for severe vertebral artery oriifce stenosis may effectively promote cerebellar function remodeling and exert neuroprotective effects.

  20. Effect of 8-day therapy with propionyl-L-carnitine on muscular and subcutaneous blood flow of the lower limbs in patients with peripheral arterial disease.

    Science.gov (United States)

    Bolognesi, M; Amodio, P; Merkel, C; Godi, L; Gatta, A

    1995-09-01

    The efficacy of propionyl-L-carnitine in increasing walking capacity in patients with peripheral arterial disease is primarily due to the metabolic effect of the drug, but a direct vasoactive action is also hypothesized. Muscular and subcutaneous blood flow of lower limbs were separately evaluated using the 133-Xenon washout technique in 10 patients with peripheral arterial disease of moderate degree, before and after 8-days of treatment with propionyl-L-carnitine (1 g orally b.i.d.). After treatment, muscular blood flow slightly increased, from 10.7 +/- 13.4 to 14.1 +/- 14.0 ml kg-1 min-1. This increase was not statistically significant (T = -1.6568, P = 0.136). Subcutaneous blood flow was not affected by the treatment (from 26.2 +/- 16.9 to 26.1 +/- 12.5 ml kg-1 min-1, T = 0.0141, P = 0.95). In conclusion, in patients with peripheral arterial disease, short-term therapy with propionyl-L-carnitine had no clinical significant effect on muscular and subcutaneous blood flow of the lower limbs. Therefore, this study suggests that the beneficial effect of this drug on the walking capacity of patients with peripheral arterial disease is not due to a direct vasoactive action. Oral administration of propionyl-L-carnitine was found to be safe, as it did not cause any change in heptic, renal or metabolic functional parameters.

  1. Geographic Variability in Potentially Discretionary Red Blood Cell Transfusions After Coronary Artery Bypass Grafting Surgery

    Science.gov (United States)

    Likosky, Donald S.; Al-Attar, Paul M.; Malenka, David J.; Furnary, Anthony P.; Lehr, Eric J.; Paone, Gaetano; Kommareddi, Mallika; Helm, Robert; Jin, Ruyun; Maynard, Chuck; Hanson, Eric C.; Olmstead, Elaine M.; Mackenzie, Todd A.; Ross, Cathy S.; Zhang, Min

    2016-01-01

    We assessed regional differences in potentially discretionary [coronary artery bypass (CABG) surgery. Regional variation in overall RBC rates remained after risk adjustment, perhaps due to differences in regional practice environments. Objective A number of established regional quality improvement collaboratives have partnered to assess and improve care across their regions under the umbrella of the “Cardiac Surgery Quality IMPROVEment (IMPROVE) Network”. The first effort of the IMPROVE Network has been to assess regional differences in potentially discretionary [coronary artery bypass (CABG) surgery across 56 medical centers in four IMPROVE Network regions between January 2008 and June 2012. Each center submitted the most recent 200 patients who received 0, 1, or 2 units of RBC transfusion during the index admission. Patient and disease characteristics, intra-operative practices, and percentage of cases receiving RBC transfusions were collected. Region-specific transfusion rates were calculated, after adjusting for pre- and intra-operative factors among region-specific centers. Results There were small, but significant, differences in patient case mix across regions. RBC transfusions of 1 or 2 units occurred among 25.2% (2,826/11,200) of CABG procedures. Significant variation in use and number of RBCs existed across regions [None: 74.8% (min:max 70.0%, 84.1%), 1 unit: 9.7% (5.1%, 11.8%), 2 units: 15.5% (9.1%, 18.2%)], p<0.001. Variation in overall transfusion rates remained after adjustment (9.1% – 31.7%, p<0.001). Conclusions Delivery of small volumes of RBC transfusions was common, yet varied across geographic regions. These data suggest that differences in regional practice environments, including transfusion triggers and anemia management, may contribute to variability in RBC transfusion rates. PMID:25227699

  2. Percutaneous transluminal renal angioplasty with stent is effective for blood pressure control and renal function improvement in atherosclerotic renal artery stenosis patients

    Institute of Scientific and Technical Information of China (English)

    LIAO Chuan-jun; YANG Bao-zhong; WANG Zhong-gao

    2012-01-01

    Background Percutaneous transluminal renal angioplasty with stent is an effective procedure for atherosclerotic renal artery stenosis.However,the decision to perform this procedure has recently raised considerable debate.The aim of this study was to assess the effects of percutaneous transluminal renal angioplasty with stent in atherosclerotic renal artery stenosis patients,especially as it relates to blood pressure control and renal function improvement.Methods A retrospective analysis was made of the clinical data from 125 atherosclerotic renal artery stenosis patients who underwent percutaneous transluminal renal angioplasty from July 2004 to June 2008 in the Department of Vascular Surgery of Beijing Chaoyang Hospital.We compared blood pressure,number of oral antihypertensive medications,and renal function changes pre and post-procedure at 24 months follow-up.Results A total of 125 atherosclerotic renal artery stenosis patients underwent percutaneous transluminal renal angioplasty and 143 stents were placed.At 24 months follow-up,both systolic and diastolic blood pressure and the number of oral antihypertensive medications were significantly reduced (P <0.05).Overall,the estimated glomerular filtration rate did not change significantly (P >0.05); however,a significant increase in estimated glomerular filtration rate was observed in the subgroup of patients with a lower baseline estimated glomerular filtration rate and in the subgroup of patients with bilateral renal artery stenosis (P <0.05).Conclusion Percutaneous transluminal renal angioplasty is a safe procedure for atherosclerotic renal artery stenosis patients,providing a significant improvement in blood pressure control and reduction in the number of oral antihypertensive medications.

  3. Pressão arterial de adolescentes de escolas particulares de Fortaleza-CE Presión arterial de adolescentes de escuelas particulares en Fortaleza-CE Blood pressure of adolescents in private schools in Fortaleza-CE

    Directory of Open Access Journals (Sweden)

    Polyana Carina Viana da Silva

    2010-01-01

    Full Text Available OBJETIVO: Identificar a pressão arterial de adolescentes de escolas particulares da cidade de Fortaleza-CE. MÉTODOS: Estudo do tipo quantitativo com delineamento transversal no qual foram investigados 794 adolescentes, entre 12-17 anos de idade de 14 escolas privadas dessa cidade no período de março a setembro de 2007, mediante aplicação de um formulário que abrangeu o registro das características sóciodemográficas, pressão arterial, Índice de Massa Corporal (IMC, prática de atividade física e glicemia capilar. RESULTADOS: Verificou-se que 19,7% dos jovens apresentavam pressão arterial elevada. Os adolescentes do sexo masculino apresentaram pressão arteial sistólica (PAS e pressão arterial diastólica (PAD maiores do que a do sexo feminino (p=0,0001. A pesquisa constatou valores maiores de PAS e PAD naqueles com excesso de peso (p=0,0001. CONCLUSÃO: A pressão arterial foi influenciada sobretudo pelo sexo e IMC.OBJETIVO: Identificar la presión arterial de adolescentes de escuelas particulares en la ciudad de Fortaleza-CE. MÉTODOS: Se trata de un estudio cuantitativo con delineamiento transversal en el cual fueron investigados 794 adolescentes - entre 12 y 17 años de edad - de 14 escuelas privadas de esa ciudad, en el período de marzo a septiembre de 2007. Se utilizó un formulario que contempló el registro de las siguientes características: socio-demográficas, presión arterial, Índice de Masa Corporal (IMC, práctica de actividad física y, glucemia capilar. RESULTADOS: Se verificó que 19,7% de los jóvenes presentaban presión arterial elevada. Los adolescentes del sexo masculino presentaron presión arterial sistólica (PAS y presión arterial diastólica (PAD mayores que las del sexo femenino (p=0,0001. La investigación constató valores mayores de PAS y PAD en aquellos con exceso de peso (p=0,0001. CONCLUSIÓN: La presión arterial fue influenciada, sobre todo, por el sexo y el IMC.OBJECTIVE: To identify the

  4. COMPARATIVE EVALUATION OF CENTRAL VENOUS VERSUS ARTERIAL BLOOD SAMPLE FOR REPETITIVE MEASUREMENTS IN CRITICALLY ILL PATIENTS ADMITTED IN INTENSIVE CARE UNIT

    Directory of Open Access Journals (Sweden)

    Rukhsana

    2015-08-01

    Full Text Available OBJECTIVES: The purpose of present study was to evaluate the reliability of central venous blood gas monitoring as an alternative to arterial blood gas monitoring and to assess that the central venous catheter is convenient and reliable source of blood for repetitive measurement of pH bicarbonate and PCO2 in critically ill patients admitted in surgical intensive care unit (SICU. METHODS: We took one hundred patients who required ABG analysis between 20 - 60 years of age. The cases were divided in four groups which constituted major admissions in SICU in one year. Out of one hundred patients for the study there were 19 Poisoning patients, 15 Trauma patients, 40 Major abdominal surgery patients, 26 Hypovolemic shock patients and others. Central Venous blood drawn within 5 min of an ABG measurement and the samples analyzed immediately on automated ABG analyzer were compared. RESULTS: Bland Altman plots demonstrated a high degree of agreement between the two corresponding sets of measurements of arterial and venous blood with coefficient of correlation 0.979 for pH. The coefficient of correlation was highly positive i.e. 0.926 for PCO 2 and 0.955 for HCO 3 - which is statistically significant. There was also positive correlation for saturation between arterial and venous blood i.e. 0.57 with clinically acceptable difference and is statistically significant. The difference in pO 2 measurements was however higher with correlation coefficient of 0.259 although the arterial saturation and finger oximetry reveals a good degree of agreement with clinically acceptable bias. CONCLUSION: Venous blood gas (VBG analysis clearly does not replace ABG analysis in determining exact pO 2 status and arterial puncture may still be required for invasive arterial BP monitoring. With positive correlation and regression plots obtained, venous samples can be used as an alternative to arterial samples depending on the significant positive correlation values obtained for

  5. The effect of siesta in parameters of cardiac structure and in interpretation of ambulatory arterial blood pressure monitoring

    Directory of Open Access Journals (Sweden)

    Marco A.M. Gomes

    2000-04-01

    Full Text Available OBJECTIVE: To evaluate the influence of the siesta in ambulatory blood pressure (BP monitoring and in cardiac structure parameters. METHODS: 1940 ambulatory arterial blood pressure monitoring tests were analyzed (Spacelabs 90207, 15/15 minutes from 7:00 to 22:00 hours and 20/20 minutes from 22:01 to 6.59hours and 21% of the records indicated that the person had taken a siesta (263 woman, 52±14 years. The average duration of the siesta was 118±58 minutes. RESULTS: (average ± standard deviation The average of systolic/diastolic pressures during wakefulness, including the napping period, was less than the average for the period not including the siesta (138±16/85±11 vs 139±16/86±11 mmHg, p5%. CONCLUSION: The siesta influenced the heart structure parameters and from a statistical point of view the average of systolic and diastolic pressures and the respective pressure loads of the wakeful period.

  6. Evaluation of Fundus Blood Flow in Normal Individuals and Patients with Internal Carotid Artery Obstruction Using Laser Speckle Flowgraphy

    Science.gov (United States)

    Akiyama, Hideo; Shimoda, Yukitoshi; Li, Danjie; Kishi, Shoji

    2017-01-01

    Purpose We investigated whether laser speckle flowgraphy (LSFG) results are comparable in both eyes and whether it is useful in the diagnosis of disparity in ocular ischemic syndrome (OIS) patients. Methods We compared the mean blur rate (MBR) value for various fundus regions in both eyes of 41 healthy subjects and 15 internal carotid artery occlusion (ICAO) cases. We calculated the standard value of the Laterality Index (LI), which was the MBR comparison of both eyes in each of the regions, in the control subjects. We then investigated the correlation between both eyes for the LIs in the entire fundus, the degree of ICAO and visual function. Results The disparity of the LIs in both eyes was least in the entire area of the fundus in control subjects and there was a significant correlation between both eyes of the 41 healthy individuals (P = 0.019). Significant correlations were found for the LI, visual acuity and degree of ICAO. The specificity and sensitivity of LI in the entire area was 93.8% and 100%, respectively. Conclusions LSFG revealed normal individuals have symmetrical fundus blood flow. LSFG could detect OIS and might be a useful tool for detecting disparities in fundus blood flow. PMID:28056061

  7. Crossed cerebellar diaschisis after stroke identified noninvasively with cerebral blood flow-weighted arterial spin labeling MRI

    Science.gov (United States)

    Strother, Megan K.; Buckingham, Cari; Faraco, Carlos C.; Arteaga, Daniel; Lu, Pengcheng; Xu, Yaomin; Donahue, Manus J.

    2015-01-01

    Background and Purpose Crossed cerebellar diaschisis (CCD) is most commonly investigated using hemodynamic PET and SPECT imaging. However, noninvasive MRI offers advantages of improved spatial resolution, allowing hemodynamic changes to be compared directly with structural findings and without concerns related to ionizing radiation exposure. The aim of this study was to evaluate relationships between CCD identified from cerebral blood flow (CBF)-weighted arterial spin labeling (ASL) MRI with cerebrovascular reactivity (CVR)-weighted blood oxygenation level dependent (BOLD) MRI, Wallerian degeneration, clinical motor impairment, and corticospinal tract involvement. Methods Subjects (n=74) enrolled in an ongoing observational stroke trial underwent CBF-weighted ASL and hypercapnic CVR-weighted BOLD MRI. Hemispheric asymmetry indices for basal cerebellar CBF, cerebellar CVR, and cerebral peduncular area were compared between subjects with unilateral supratentorial infarcts (n=18) and control subjects without infarcts (n=16). CCD required (1) supratentorial infarct and (2) asymmetric cerebellar CBF (>95% confidence interval relative to controls). Results In CCD subjects (n=9), CVR (p=0.04) and cerebral peduncular area (p < 0.01) were significantly asymmetric compared to controls. Compared to infarct subjects not meeting CCD criteria (n=9), CCD subjects had no difference in corticospinal tract location for infarct (p=1.0) or motor impairment (p=0.08). Conclusions CCD correlated with cerebellar CVR asymmetry and Wallerian degeneration. These findings suggest that noninvasive MRI may be a useful alternative to PET or SPECT to study structural correlates and clinical consequences of CCD following supratentorial stroke. PMID:26724658

  8. Changes of Umbilical Artery Blood Flow Due to Pregnancy Induced Hypertension in the Third Trimester of Pregnancy

    Directory of Open Access Journals (Sweden)

    Sarah Hashemi

    2010-05-01

    Full Text Available Background/Objective: Doppler ultrasound of umbilical vessels is a method of evaluating fetoplacental blood flow which is very important in high risk pregnancies including pregnancy induced hypertension and may predict both the duration of maternal hospitalization and fetal mortality rates in IUGR. In this study, Doppler indices of blood flow through the umbilical artery were measured in patients with pregnancy induced hypertension."nPatients and Methods: This study was a cross-sectional study which was carried out on 101 preg-nant women: 35 patients with pregnancy induced hypertension were in the case group that had no symptoms or signs of pre-eclampsia, eclampsia or diabetes melitus. 61 normal pregnant women were as the control group. All the patients were studied in their third trimester of pregnancy. Doppler ultrasound of the umbilical artery was performed for both the case and the control groups. Peak Systolic Velocity (PSV, End Diastolic Velocity (EDV and mean velocity were measured. The Resistive Index (RI, Pulsatility Index (PI and Systolic to diastolic ratio (S/D ratio were calculated. The statistical analysis was performed on the obtained recorded data, using SPSS software."nResults: The calculated mean values of spectral Doppler indices in the case group were: 0.77 for RI; 1.39 for PI and 4.88 for S/D ratio while in the control group they were calculated as 0.64, 1.08 and 2.97, respectively. Altogether, comparison of the mean values of the mentioned indices revealed a significant difference between the two groups (P<0.01. The case group was significantly rated higher in terms of the above mentioned indices."nConclusion: In patients with pregnancy induced hypertension without any complications (such as pre-eclampsia or eclampsia or without any other risk factors (such as diabetes mellitus and IUGR, Doppler ultrasound should be used for evaluating the degree of fetoplacental blood flow in order to decrease the risk of pregnancy

  9. Dynamic contrast-enhanced MRI assessment of hyperemic fractional microvascular blood plasma volume in peripheral arterial disease: initial findings.

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    Bas Versluis

    Full Text Available OBJECTIVES: The aim of the current study was to describe a method that assesses the hyperemic microvascular blood plasma volume of the calf musculature. The reversibly albumin binding contrast agent gadofosveset was used in dynamic contrast-enhanced magnetic resonance imaging (DCE MRI to assess the microvascular status in patients with peripheral arterial disease (PAD and healthy controls. In addition, the reproducibility of this method in healthy controls was determined. MATERIALS AND METHODS: Ten PAD patients with intermittent claudication and 10 healthy control subjects were included. Patients underwent contrast-enhanced MR angiography of the peripheral arteries, followed by one DCE MRI examination of the musculature of the calf. Healthy control subjects were examined twice on different days to determine normative values and the interreader and interscan reproducibility of the technique. The MRI protocol comprised dynamic imaging of contrast agent wash-in under reactive hyperemia conditions of the calf musculature. Using pharmacokinetic modeling the hyperemic fractional microvascular blood plasma volume (V(p, unit: % of the anterior tibial, gastrocnemius and soleus muscles was calculated. RESULTS: V(p was significantly lower for all muscle groups in PAD patients (4.3±1.6%, 5.0±3.3% and 6.1±3.6% for anterior tibial, gastrocnemius and soleus muscles, respectively compared to healthy control subjects (9.1±2.0%, 8.9±1.9% and 9.3±2.1%. Differences in V(p between muscle groups were not significant. The coefficient of variation of V(p varied from 10-14% and 11-16% at interscan and interreader level, respectively. CONCLUSIONS: Using DCE MRI after contrast-enhanced MR angiography with gadofosveset enables reproducible assessment of hyperemic fractional microvascular blood plasma volume of the calf musculature. V(p was lower in PAD patients than in healthy controls, which reflects a promising functional (hemodynamic biomarker for the

  10. The pharmacist and the management of arterial hypertension: the role of blood pressure monitoring and telemonitoring.

    Science.gov (United States)

    Omboni, Stefano; Sala, Elisa

    2015-02-01

    Randomized controlled trials have documented that a team of health care professionals which includes a physician, a nurse and a community pharmacist may improve the benefit and adherence of anti-hypertensive therapy. If such a health care model relies on blood pressure telemonitoring, it can promote a stronger relationship between health care professionals and patients, and further improve BP control of hypertension. The major benefit of this collaborative approach is to center the patient's management in a tailored way, providing comprehensive and preventive care based on health information technologies. In this review, the authors summarize recent clinical studies that evaluate the role of the community pharmacist in BP measurements, and in hypertension screening and control. The authors also describe the advantages of using blood pressure telemonitoring in home and ambulatory settings to evaluate potential alternatives to primary care in hypertension management.

  11. Effects of blood storage on ice in biochemical and arterial blood gas analysis of rats Efeitos da estocagem sanguínea em gelo na bioquímica e gasometria arterial de ratos

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    Marcus Vinicius Henriques Brito

    2008-10-01

    Full Text Available PURPOSE: To investigate the effects of blood storage in biochemical and arterial blood gas analysis of Wistar rats. METHODS: Ten adult male rats with weights between 300-350 g were used. The catheterization of the internal carotid artery were performed, followed by withdrawal of 3 ml of blood using 3 separate syringes each containing 1 ml. The syringes were fulfilled one after another and numerated according to the order of collection. Then, the following groups were devised: GT1 - samples that were firstly analyzed in 20 minutes and the second exam 65 minutes after the collection; GT2 - samples that were firstly analyzed in 35 minutes and the second exam 80 minutes after the collection; GT3 - samples that were firstly analyzed in 50 minutes and the second exam 95 minutes after the collection. The samples were stored in a container with a temperature between 0 Cº and 4 Cº. Upon analysis the values of pH, PaCO2, PaO2, HCO3-, SatO2, SBE, Na+ and K+ concentrations and glucose were compared. RESULTS: No statistically relevant difference (pOBJETIVO: Analisar o efeito da estocagem sanguínea na bioquímica e na gasometria do sangue arterial de ratos Wistar. MÉTODOS: Foram utilizados 10 ratos adultos, machos, com peso compreendido entre 300 a 350 gramas. Cada animal foi submetido à cateterização da artéria carótida seguida de heparinização prévia do animal. Foram colhidos 3 ml de sangue total do rato, separados em três seringas contendo 1 ml cada. As seringas foram preenchidas uma após a outra e enumeradas respectivamente à ordem de coleta. De acordo com esta numeração as amostras foram distribuídas nos seguintes grupos: GT1 - amostras que tiveram primeira análise em 20 minutos e a segunda análise 65 minutos após a coleta; GT2 - amostras que tiveram primeira análise em 35 minutos e segunda análise 80 minutos após a coleta; GT3 - amostras que tiveram primeira análise em 50 minutos e 95 minutos após a coleta. As amostras foram

  12. Prevalência de pressão arterial elevada em crianças e adolescentes: revisão sistemática The prevalence of high arterial blood pressure in children and adolescents: a systematic review

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    Diego Giulliano Destro Christofaro

    2011-12-01

    Full Text Available OBJETIVOS: identificar as prevalências de pressão arterial elevada em crianças e adolescentes em estudos publicados nos últimos 30 anos. MÉTODOS: foi realizada uma busca nas seguintesbases de dados: Medline/PubMed, Lilacs, Web ofScience, Embase e Scielo entre os anos de 1980 e 2009. Foram incluídos estudos originais de prevalência de pressão arterial elevada ou hipertensão com tamanho amostral superior a 500sujeitos. RESULTADOS: a prevalência de pressão arterial elevada em crianças e adolescentes de 4 a 20 anos variou de 0,46% a 20,6%. As menores prevalências de pressão arterial elevada foram detectadas nos estudos em que a maior parte da amostra foi composta por crianças de 4 a 7 anos. Os protocolos mais utilizados na avaliação da pressão arterial foram o da Task Force e o do National High Blood Pressure Education Program. Ao todo 52,4% dos estudos utilizaram o método auscultatório para verificar a medida de pressão arterial e 47,6%, o método oscilométrico. CONCLUSÕES: apesar da grande discrepância dos valores de prevalência encontrados, ressalta-se ocrescimento da prevalência de pressão arterial elevada na população de crianças e adolescentes de diversas partes do mundo.OBJECTIVES: to identify the prevalence of high blood pressure in children and adolescents in studiespublished in the past 30 years. METHODS: a search was carried out in the Medline/PubMed, Lilacs, Web of Science, Embase and Scielo databases for articles published between 1980 and 2009. Articles were included if they were original studies of the prevalence of high arterial blood pressure or hypertension in a sample of more than 500 subjects. RESULTS: the prevalence of high blood pressure (in individuals aged between 4 and 20 years varied from 0.46% to 20.6%. The lower prevalence of high blood pressure was found in studies where the majority ofthe sample was aged between 4 and 7 years. Theprotocols most commonly used for evaluation of blood pressure

  13. Simultaneous mapping of temporally-resolved blood flow velocity and oxygenation in femoral artery and vein during reactive hyperemia

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    Langham Michael C

    2011-10-01

    Full Text Available Abstract Background Post-occlusive hyperemia is often used as a paradigm to evaluate vascular reactivity, for example by measuring post-ischemic flow-mediated dilation, arterial blood flow or temporally resolved venous blood oxygenation (HbO2. Here we demonstrate the feasibility of a simultaneous measurement of blood flow and HbO2 in the femoral circulation as part of a single procedure. Methods A multi-echo GRE pulse sequence was designed and implemented to collect velocity-encoded projections in addition to full-image echoes for field mapping as a means to quantify intravascular magnetic susceptibility. The method's feasibility was evaluated at 3T in a small pilot study involving two groups of healthy subjects (mean ages 26 ± 1.6 and 59 ± 7.3 years, N = 7 and 5, respectively in terms of six parameters characterizing the time-course of reactive hyperemia and their sensitivity to differentiate age effects. The reproducibility was assessed on two of the seven young healthy subjects with three repeated measurements. Results The physiological parameters agree with those obtained with current methods that quantify either velocity or HbO2 alone. Of the six measures of vascular reactivity, one from each group was significantly different in the two subject groups (p Conclusion The proposed method is able quantify multiple parameters that may lead to more detailed assessment of peripheral vascular reactivity in a single cuff paradigm rather than in separate procedures as required previously, thereby improving measurement efficiency and patient comfort.