Uptake and distribution of a labeled fatty acid in a canine model of ischemia with and without reperfusion

International Nuclear Information System (INIS)

Devous, M.D. Sr.

1985-01-01

The relationship between regional myocardial blood flow (RMBF) and the regional distribution of 15-(4-iodophenyl)-9-methyl pentadecanoic acid (9-MPDA) was studied in a canine model of myocardial ischemia with and without reperfusion. Group 1 dogs received 135 min of left anterior descending coronary artery (LAD) occlusion; Group 2 dogs received 90 min of LAD occlusion and 45 min of reflow; and Group 3 dogs received 90 min of LAD occlusion and 3.5 hr of reperfusion. All animals received 9-MPDA 15 min prior to sacrifice, and tracer microspheres prior to occlusion, 5 and 80 min after occlusion, 15 min after reperfusion, and 15 min before the end of reperfusion. In Group 1 (permanent ischemia), 9-MPDA distribution was closely correlated with RMBF both 5 and 80 min after occlusion. In Group 2, 9-MPDA uptake was most closely correlated with reperfusion RMBF rather than ischemic RMBF. However, in 1 animal with good reperfusion, 9-MPDA uptake was reduced and was correlated with ischemic blood flow measured 5 min after occlusion. In Group 3, 9-MPDA uptake was correlated with RMBF measured during the ischemic period and not with reperfusion RMBF. It appears that 9-MPDA uptake is determined by RMBF when flow is limited, or early in reperfusion. With prolonged reperfusion, 9-MPDA uptake is significantly reduced in the ischemic zone in the presence of normal flow. This finding implies that the uptake of this fatty acid during reperfusion is related to myocardial damage (myocardial metabolism?) and not to RMBF

Multi-modal assessment of neurovascular coupling during cerebral ischaemia and reperfusion using remote middle cerebral artery occlusion

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Sutherland, Brad A; Fordsmann, Jonas C; Martin, Chris

2017-01-01

. Male Wistar rats were subjected to remote middle cerebral artery occlusion, where a long filament was advanced intraluminally through a guide cannula in the common carotid artery. Transcallosal stimulation evoked increases in blood flow, tissue oxygenation and neuronal activity, which were diminished...... that neurovascular dysfunction was not sustained. These data show for the first time that the rat remote middle cerebral artery occlusion model coupled with transcallosal stimulation provides a novel method for continuous assessment of hyperacute neurovascular coupling changes during ischaemia and reperfusion......Hyperacute changes in cerebral blood flow during cerebral ischaemia and reperfusion are important determinants of injury. Cerebral blood flow is regulated by neurovascular coupling, and disruption of neurovascular coupling contributes to brain plasticity and repair problems. However, it is unknown...

Defibrotide reduces infarct size in a rabbit model of experimental myocardial ischaemia and reperfusion.

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Thiemermann, C.; Thomas, G. R.; Vane, J. R.

1989-01-01

1. Defibrotide, a single-stranded polydeoxyribonucleotide obtained from bovine lungs, has significant anti-thrombotic, pro-fibrinolytic and prostacyclin-stimulating properties. 2. The present study was designed to evaluate the effects of defibrotide on infarct size and regional myocardial blood flow in a rabbit model of myocardial ischaemia and reperfusion. 3. Defibrotide (32 mg kg-1 bolus + 32 mg kg-1 h-1, i.v.) either with or without co-administration of indomethacin (5 mg kg-1 x 2, i.v.) was administered 5 min after occlusion of the left anterior-lateral coronary artery and continued during the 60 min occlusion and subsequent 3 h reperfusion periods. 4. Defibrotide significantly attenuated the ischaemia-induced ST-segment elevation and abolished the reperfusion-related changes (R-wave reduction and Q-wave development) in the electrocardiogram. In addition, defibrotide significantly improved myocardial blood flow in normal and in ischaemic, but not in infarcted sections of the heart. The improvement in blood flow in normal perfused myocardium, but not in the ischaemic area was prevented by indomethacin. 5. Although the area at risk was similar in all animal groups studied, defibrotide treatment resulted in a 51% reduction of infarct size. Indomethacin treatment abolished the reduction of infarct size seen with defibrotide alone. 6. The data demonstrate a considerable cardioprotective effect of defibrotide in the reperfused ischaemic rabbit myocardium. This effect may be related, at least in part, to a stimulation of endogenous prostaglandin formation. Other possible mechanisms are discussed. PMID:2758223

Cyclical blood flow restriction resistance exercise: a potential parallel to remote ischemic preconditioning?

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Sprick, Justin D; Rickards, Caroline A

2017-11-01

Remote ischemic preconditioning (RIPC) is characterized by the cyclical application of limb blood flow restriction and reperfusion and has been shown to protect vital organs during a subsequent ischemic insult. Blood flow restriction exercise (BFRE) similarly combines bouts of blood flow restriction with low-intensity exercise and thus could potentially emulate the protection demonstrated by RIPC. One concern with BFRE, however, is the potential for an augmented rise in sympathetic outflow due to greater activation of the exercise pressor reflex. Because of the use of lower workloads, however, we hypothesized that BFRE would elicit an attenuated increase in sympathetic outflow [assessed via plasma norepinephrine (NE) and mean arterial pressure (MAP)] and middle cerebral artery velocity (MCAv) when compared with conventional exercise (CE). Fifteen subjects underwent two leg press exercise interventions: 1 ) BFRE-220 mmHg bilateral thigh occlusion at 20% 1 rep-max (1RM), and 2 ) CE-65% 1RM without occlusion. Each condition consisted of 4 × 5-min cycles of exercise, with 3 × 10-reps in each cycle. Five minutes of rest and reperfusion (for BFRE) followed each cycle. MAP increased with exercise ( P exercise ( P exercise only ( P = 0.07). Plasma NE concentration increased with CE only ( P exercise ( P ≤ 0.02). The attenuated sympathetic response, combined with similar cerebrovascular responses, suggest that cyclical BFRE could be explored as an alternative to CE in the clinical setting. Copyright © 2017 the American Physiological Society.

[The effect of portal blood stasis on lung and renal injury induced by hepatic ischemia reperfusion in a rabbit model].

Science.gov (United States)

Wang, Ye; Yang, Jia-mei; Hou, Yuan-kai; Li, Dian-qi; Hu, Ming-hua; Liu, Peng

2008-04-15

To investigate the effect and mechanism of portal blood stasis on lung and renal injury induced by hepatic ischemia reperfusion. A rabbit hepatic ischemia reperfusion injury model was established by hepatic portal occlusion and in situ hypothermic irrigation for 30 min. Twenty-four New Zealand white rabbits were employed and randomly divided into 3 groups equally by different dosage of portal blood stasis removal: group A5 (5 ml blood removal), group A10 (10 ml blood removal),and group B (no blood removal). Eight rabbits were served as controls with no hepatic portal occlusion and hypothermic irrigation. After reperfusion 4 h serum endotoxin content, tumor necrosis factor-alpha (TNF-alpha), urea nitrogen (BUN), and creatinine (Cr) were examined respectively, meantime lung and kidney tissues were sampled to determine the content of malondialdehyde (MDA), superoxide dismutase (SOD), the pathology, and wet to dry weight ratio, broncho-alveolar lavage fluid protein content in lung tissues. Removing portal blood stasis ameliorated lung and renal injury as shown by decreasing the level of serum endotoxin, TNF-alpha, BUN, Cr, wet to dry weight ratio, broncho-alveolar lavage fluid protein content, MDA, SOD. TNF-alpha, Cr, broncho-alveolar lavage fluid protein content in lung tissues and MDA in kidney tissue in group A5 were significantly reduced compared with those in group B (P portal blood stasis before the resume of splanchnic circulation may ameliorate the lung and renal injury induced by hepatic ischemia reperfusion. The possible mechanism may be that portal blood stasis removal reduces endotoxin absorption, and further decreases production of serum TNF-alpha.

Hypoperfusion Induced by Preconditioning Treadmill Training in Hyper-Early Reperfusion After Cerebral Ischemia: A Laser Speckle Imaging Study.

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He, Zhijie; Lu, Hongyang; Yang, Xiaojiao; Zhang, Li; Wu, Yi; Niu, Wenxiu; Ding, Li; Wang, Guili; Tong, Shanbao; Jia, Jie

2018-01-01

Exercise preconditioning induces neuroprotective effects during cerebral ischemia and reperfusion, which involves the recovery of cerebral blood flow (CBF). Mechanisms underlying the neuroprotective effects of re-established CBF following ischemia and reperfusion are unclear. The present study investigated CBF in hyper-early stage of reperfusion by laser speckle contrast imaging, a full-field high-resolution optical imaging technique. Rats with or without treadmill training were subjected to middle cerebral artery occlusion followed by reperfusion. CBF in arteries, veins, and capillaries in hyper-early stage of reperfusion (1, 2, and 3 h after reperfusion) and in subacute stage (24 h after reperfusion) were measured. Neurological scoring and 2,3,5-triphenyltetrazolium chloride staining were further applied to determine the neuroprotective effects of exercise preconditioning. In hyper-early stage of reperfusion, CBF in the rats with exercise preconditioning was reduced significantly in arteries and veins, respectively, compared to rats with no exercise preconditioning. Capillary CBF remained stable in the hyper-early stage of reperfusion, though it increased significantly 24 h after reperfusion in the rats with exercise preconditioning. As a neuroprotective strategy, exercise preconditioning reduced the blood perfusion of arteries and veins in the hyper-early stage of reperfusion, which indicated intervention-induced neuroprotective hypoperfusion after reperfusion onset.

Early assessment of tissue viability with radioiodinated heptadecanoic acid in reperfused canine myocardium: Comparison with thallium-201

International Nuclear Information System (INIS)

Chappuis, F.; Meier, B.; Belenger, J.; Blaeuenstein, P.L.; Lerch, R.

1990-01-01

Myocardial scintigraphy with heptadecanoic acid labeled with iodine-123 (123I-HDA) may allow early noninvasive delineation of viable myocardium after reperfusion. In this study myocardial uptake of 123I-HDA was compared with that of thallium-201 in six closed-chest dogs after 5 hours of occlusion followed by 1 hour of reperfusion of the left anterior descending coronary artery. Myocardial blood flow was measured with microspheres, and myocardial viability was assessed by means of triphenyltetrazolium chloride staining. In viable areas of the reperfused region, 123I-HDA uptake, thallium-201 uptake, and myocardial blood flow were similar to those measured in the control circumflex region. However, in infarcted areas they were reduced to 48 +/- 2% (mean +/- SEM; p less than 0.001), 59 +/- 3% (p less than 0.001), and 74 +/- 5% (p less than 0.001) of control values, respectively. Results of multiple regression analysis showed that thallium-201 uptake primarily reflected the level of flow during reperfusion, whereas 123I-HDA uptake was dependent on both myocardial blood flow and viability. At each level of flow, 123I-HDA uptake was significantly lower in infarcted than in viable myocardium. By means of discriminant analysis, 123I-HDA uptake was found to be the single most important predictor of viability, whereas thallium-201 was only of limited importance. Myocardial 123I-HDA uptake greater than or equal to 71% or myocardial thallium-201 uptake greater than or equal to 73% best differentiated viable from infarcted myocardium. According to these criteria, 123I-HDA predicted myocardial viability with a sensitivity of 77%, a specificity of 84% and a predictive accuracy of 81%

Haemoadsorption reduces the inflammatory response and improves blood flow during ex vivo renal perfusion in an experimental model.

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Hosgood, Sarah A; Moore, Tom; Kleverlaan, Theresa; Adams, Tom; Nicholson, Michael L

2017-10-25

Ex-vivo normothermic perfusion strategies are a promising new instrument in organ transplantation. The perfusion conditions are designed to be protective however the artificial environment can induce a local inflammatory response. The aim of this study was to determine the effect of incorporating a Cytosorb adsorber into an isolated kidney perfusion system. Porcine kidneys were subjected to 22 h of cold ischaemia then reperfused for 6 h on an ex vivo reperfusion circuit. Pairs of kidneys were randomised to either control (n = 5) or reperfusion with a Cytosorb adsorber (n = 5) integrated into the circuit. Tissue, blood and urine samples were taken for the measurement of inflammation and renal function. Baseline levels of cytokines (IL-6, TNFα, IL-8, IL-10, IL-1β, IL-1α) were similar between groups. Levels of IL-6 and IL-8 in the perfusate significantly increased during reperfusion in the control group but not in the Cytosorb group (P = 0.023, 0.049). Levels of the other cytokines were numerically lower in the Cytosorb group; however, this did not reach statistical significance. The mean renal blood flow (RBF) was significantly higher in the Cytosorb group (162 ± 53 vs. 120 ± 35 mL/min/100 g; P = 0.022). Perfusate levels of prostaglandin E2 were significantly lower in the Cytosorb group (642 ± 762 vs. 3258 ± 980 pg/mL; P = 0.0001). Levels of prostacyclin were significantly lower in the Cytosorb group at 1, 3 and 6 h of reperfusion (P = 0.008, 0.003, 0.0002). Levels of thromboxane were also significantly lower in the Cytosorb group throughout reperfusion (P = 0.005). Haemoadsorption had no effect on creatinine clearance (P = 0.109). Haemoadsorption can reduce the inflammatory response and improve renal blood flow during perfusion. Nonetheless, in this model haemoadsorption had no influence on renal function and this may relate to the broad-spectrum action of the Cytosorb adsorber that also removes potentially important anti

Prediction of infarction and reperfusion in stroke by flow- and volume-weighted collateral signal in MR angiography.

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Ernst, M; Forkert, N D; Brehmer, L; Thomalla, G; Siemonsen, S; Fiehler, J; Kemmling, A

2015-02-01

In proximal anterior circulation occlusive strokes, collateral flow is essential for good outcome. Collateralized vessel intensity in TOF- and contrast-enhanced MRA is variable due to different acquisition methods. Our purpose was to quantify collateral supply by using flow-weighted signal in TOF-MRA and blood volume-weighted signal in contrast-enhanced MRA to determine each predictive contribution to tissue infarction and reperfusion. Consecutively (2009-2013), 44 stroke patients with acute proximal anterior circulation occlusion met the inclusion criteria with TOF- and contrast-enhanced MRA and penumbral imaging. Collateralized vessels in the ischemic hemisphere were assessed by TOF- and contrast-enhanced MRA using 2 methods: 1) visual 3-point collateral scoring, and 2) collateral signal quantification by an arterial atlas-based collateral index. Collateral measures were tested by receiver operating characteristic curve and logistic regression against 2 imaging end points of tissue-outcome: final infarct volume and percentage of penumbra saved. Visual collateral scores on contrast-enhanced MRA but not TOF were significantly higher in patients with good outcome. Visual collateral scoring on contrast-enhanced MRA was the best rater-based discriminator for final infarct volume 50% (area under the curve, 0.67; P = .04). Atlas-based collateral index of contrast-enhanced MRA was the overall best independent discriminator for final infarct volume of collateral index combining the signal of TOF- and contrast-enhanced MRA was the overall best discriminator for effective reperfusion (percentage of penumbra saved >50%; area under the curve, 0.89; P collateral assessment, TOF- and contrast-enhanced MRA both contain predictive signal information for penumbral reperfusion. This could improve risk stratification in further studies. © 2015 by American Journal of Neuroradiology.

Effects of dexmedetomidine on microregional O2 balance during reperfusion after focal cerebral ischemia.

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Chi, Oak Z; Grayson, Jeremy; Barsoum, Sylviana; Liu, Xia; Dinani, Aliraza; Weiss, Harvey R

2015-01-01

This study was performed to determine whether there is an association between microregional O2 balance and neuronal survival in cerebral ischemia-reperfusion using dexmedetomidine, an α2-adrenoreceptor agonist and a sedative. Rats were subjected to 1 hour middle cerebral artery occlusion and a 2-hour reperfusion. During reperfusion, normal saline (n = 14) or dexmedetomidine 1 μg/kg/minute (n = 14) was infused intravenously. At 2 hours of reperfusion, regional cerebral blood flow using (14)C-iodoantipyrine autoradiography, microregional arterial and venous (20-60 μm in diameter) O2 saturation (SvO2) using cryomicrospectrophotometry, and the size of cortical infarction were determined. Ischemia-reperfusion decreased microregional SvO2 (52.9 ± 3.7% vs. 61.1 ± .6%, P < .005) with increased variation or heterogeneity (P < .0001) with similar regional cerebral blood flow and O2 consumption. Dexmedetomidine during reperfusion decreased the heterogeneity of SvO2 that was analyzed with an analysis of variance (P < .01) and reported as coefficient of variation (100 × standard deviation/Mean) (11.8 vs. 16.4). The number of veins with O2 saturation less than 50% decreased with dexmedetomidine (13/80 vs. 27/81, P < .01). The percentage of cortical infarct in total cortex was smaller with dexmedetomidine (8.3 ± 2.2% vs. 12.6 ± 1.5%, P < .005). In the cerebral ischemic reperfused cortex, dexmedetomidine decreased the heterogeneity of SvO2 and the number of small veins with low O2 saturation suggesting improved microregional O2 supply/consumption balance. The improvement was accompanied by the reduced size of cortical infarction. Copyright © 2015 National Stroke Association. Published by Elsevier Inc. All rights reserved.

Rat Pial Microvascular Changes During Cerebral Blood Flow Decrease and Recovery: Effects of Cyanidin Administration

Directory of Open Access Journals (Sweden)

Teresa Mastantuono

2018-05-01

Full Text Available The reactive oxygen species (ROS are known to play a major role in many pathophysiological conditions, such as ischemia and reperfusion injury. The present study was aimed to evaluate the in vivo cyanidin (anthocyanin effects on damages induced by rat pial microvascular hypoperfusion-reperfusion injury by cerebral blood flow decrease (CBFD and subsequent cerebral blood flow recovery (CBFR. In particular, the main purpose was to detect changes in ROS production after cyanidin administration. Rat pial microvasculature was investigated using fluorescence microscopy through a cranial window (closed; Strahler's method was utilized to define the geometric features of pial vessels. ROS production was investigated in vivo by 2′-7′-dichlorofluorescein-diacetate assay and neuronal damage was measured on isolated brain sections by 2,3,5-triphenyltetrazolium chloride staining. After 30 min of CBFD, induced by bilateral common carotid artery occlusion, and 60 min of CBFR, rats showed decrease of arteriolar diameter and capillary perfusion; furthermore, increase in microvascular leakage and leukocyte adhesion was observed. Conversely, cyanidin administration induced dose-related arteriolar dilation, reduction in microvascular permeability as well as leukocyte adhesion when compared to animals subjected to restriction of cerebral blood flow; moreover, capillary perfusion was protected. ROS generation increase and marked neuronal damage were detected in animals subjected to CBFD and CBFR. On the other hand, cyanidin was able to reduce ROS generation and neuronal damage. In conclusion, cyanidin treatment showed dose-related protective effects on rat pial microcirculation during CBFD and subsequent CBFR, inducing arteriolar dilation by nitric oxide release and inhibiting ROS formation, consequently preserving the blood brain barrier integrity.

[Vasoprotective effect of adaptation to hypoxia in myocardial ischemia and reperfusion injury].

Science.gov (United States)

Manukhina, E B; Terekhina, O L; Belkina, L M; Abramochkin, D V; Budanova, O P; Mashina, S Yu; Smirin, B V; Yakunina, E B; Downey, H F

2013-01-01

Adaptation to hypoxia is known to be cardioprotective in ischemic and reperfusion (IR) injury of the myocardium. This study was focused on investigating a possibility for prevention of endothelial dysfunction in IR injury of the rat heart using adaptation to intermittent hypoxia, which was performed in a cyclic mode (5-10 min of hypoxia interspersed with 4 min of normoxia, 5-8 cycles daily) for 21 days. Endothelial function of coronary blood vessels was evaluated after the in vitro IR of isolated heart (15 min of ischemia and 10 min of reperfusion) by the increment of coronary flow rate in response to acetylcholine. Endothelium-dependent relaxation of isolated rat aorta was evaluated after the IR myocardial injury in situ (30 min of ischemia and 60 min of reperfusion) by a relaxation response of noradrenaline-precontracted vessel rings to acetylcholine. The following major results were obtained in this study: 1) IR myocardial injury induced endothelial dysfunction of coronary blood vessels and the aorta, a non-coronary blood vessel, remote from the IR injury area; and 2) adaptation to hypoxia prevented the endothelial dysfunction of both coronary and non-coronary blood vessels associated with the IR injury. Therefore, adaptation to hypoxia is not only cardioprotective but also vasoprotective in myocardial IR injury.

Substrate use in ischemic and reperfused canine myocardium: quantitative considerations

International Nuclear Information System (INIS)

Myears, D.W.; Sobel, B.E.; Bergmann, S.R.

1987-01-01

The patterns of use of substrate in reperfused myocardium are not yet well elucidated, and their delineation is essential for adequate interpretation of results of analyses performed after positron emission tomography with labeled substrates to differentiate normal from abnormal heart muscle. Accordingly, in open-chest, anesthetized dogs the authors measured glucose and fatty acid utilization in normal, ischemic, and reperfused myocardium and assessed the contributions of metabolism of each substrate to overall oxidative metabolism. Intracoronary [ 3 H]glucose and [ 14 C]palmitate were administered in five control dogs, eight dogs subjected to 1 h of coronary occlusion, and nine dogs subjected to reperfusion after 1 h of ischemia. Regional coronary venous blood samples were assayed sequentially. In reperfused myocardium, utilization of glucose was 103% greater than that in ischemic and 273% greater than in normal myocardium. Utilization of fatty acid during reperfusion, although greater than that in ischemic myocardium, was significantly less than that in normal myocardium despite restoration of flow to 80% of control values. Despite diminished net uptake of fatty acid, oxidation of fatty acid accounted for 63% of total oxygen consumption in reperfused myocardium. These studies indicate that canine myocardium reperfused after 1 h of ischemia exhibits enhanced uptake of glucose and impaired utilization of palmitate. Nevertheless, palmitate continues to comprise the substrate primarily utilized for oxidative metabolism

Determinants of myocardial hemorrhage after coronary reperfusion in the anesthetized dog

International Nuclear Information System (INIS)

Higginson, L.A.J.; White, F.; Heggtveit, H.A.; Sanders, T.M.; Bloor, C.M.; Covell, J.W.

1982-01-01

Intramyocardial hemorrhage often occurs with reperfusion in experimental acute myocardial infarction and is thought to be associated with extension of necrosis. To determine if hemorrhage was associated with extension of necrosis, 10 anesthetized dogs were reperfused after 6 hours of circumflex coronary artery occlusion and 10 others had control occlusion with no reperfusion. Fifteen of the 20 reperfused dogs had gross hemorrhage and none of the control dogs did. In 12 reperfused and 10 control dogs, radioactive microspheres were injected after coronary occlusion to quantitate collateral flow and in the reperfusion group microspheres were injected to quantitate reflow. Complete flow data were available in eight reperfused and 10 analyzed for hemorrhage, collateral flow and creatine kinase activity. Serial microscopic examination was performed in eight additional dogs reperfused after 6 hours to determine if hemorrhage occurs into otherwise microscopically normal myocardium. Pathologic examination indicatd that hemorrhage did not occur into otherwise microscopically normal myocardium. These studies indicate that hemorrhage or reperfusion is associated with severe myocardial necrosis and markedly depressed flow before reperfusion and this occurs only into myocardium already markedly compromised at the time of reperfusion

Importance of tissue perfusion in ST segment elevation myocardial infarction patients undergoing reperfusion strategies: role of adenosine.

Science.gov (United States)

Forman, Mervyn B; Jackson, Edwin K

2007-11-01

High risk ST segment elevation myocardial infarction (STEMI) patients undergoing reperfusion therapy continue to exhibit significant morbidity and mortality due in part to myocardial reperfusion injury. Importantly, preclinical studies demonstrate that progressive microcirculatory failure (the "no-reflow" phenomenon) contributes significantly to myocardial reperfusion injury. Diagnostic techniques to measure tissue perfusion have validated this concept in humans, and it is now clear that abnormal tissue perfusion occurs frequently in STEMI patients undergoing reperfusion therapy. Moreover, because tissue perfusion correlates poorly with epicardial blood flow (TIMI flow grade), clinical studies show that tissue perfusion is an independent predictor of early and late mortality in STEMI patients and is associated with infarct size, ventricular function, CHF and ventricular arrhythmias. The mechanisms responsible for abnormal tissue perfusion are multifactorial and include both mechanical obstruction and vasoconstrictor humoral factors. Adenosine, an endogenous nucleoside, maintains microcirculatory flow following reperfusion by activating four well-characterized extracellular receptors. Because activation of adenosine receptors attenuates the mechanical and functional mechanisms leading to the "no reflow" phenomenon and activates other cardioprotective pathways as well, it is not surprising that both experimental and clinical studies show striking myocardial salvage with intravenous infusions of adenosine administered in the peri-reperfusion period. For example, a post hoc analysis of the AMISTAD II trial indicates a significant reduction in 1 and 6-month mortality in STEMI patients undergoing reperfusion therapy who are treated with adenosine within 3 hours of symptoms. In conclusion, adenosine's numerous cardioprotective effects, including attenuation of the "no-reflow" phenomenon, support its use in high risk STEMI undergoing reperfusion.

Evaluation of nonradioactive, colored microspheres for measurement of regional myocardial blood flow in dogs

International Nuclear Information System (INIS)

Hale, S.L.; Alker, K.J.; Kloner, R.A.

1988-01-01

Measurement of regional myocardial blood flow (RMBF) is crucial in experimental studies of myocardial ischemia and reperfusion in dogs. The standard measurement technique uses radioactive microspheres; however, not all institutions are able to dispose of radioactive waste and therefore cannot make use of this method. We tested a new, nonradioactive microsphere, labeled with colors instead of nuclides. Simultaneous blood flow measurements with two nuclide-labeled and two colored microspheres were performed after coronary occlusion in dogs. Both techniques show a within-method correlation of r greater than 0.98. Duplicate variability for paired RMBF values in 80 samples was 8.7 +/- 0.1% when computed with radioactive microspheres and 13.2 +/- 1.8% when computed with colored microspheres. There was a good correlation in the measurement of RMBF between the radioactive- and colored-microsphere methods (r = 0.98). The best-fitting linear regression line was expressed by the formula: Colored-microsphere RMBF = 1.11 (radioactive-microsphere RMBF)-0.02. When measured by colored microspheres, RMBF was approximately 8% higher than when computed with radioactive microspheres for blood flow values of 0-2 ml/min/g. When blood flow was increased pharmacologically to levels of 2-7.5 ml/min/g, colored microspheres yielded blood flow values 39% higher than the values computed by radioactive microspheres. We conclude that the nonradioactive, colored-microsphere method correlates with the radioactive technique, but at high flows, it yields values greater than those obtained with radioactive microspheres

Gastric mucosal electrical potential difference, pH, blood flow, and morphology during hypoxia and selective gastric ischaemia with and without allopurinol pretreatment in anaesthetized dogs

DEFF Research Database (Denmark)

Højgaard, L; Bülow, J B; Madsen, J

1990-01-01

Ischaemia has been implicated in the pathogenesis of gastric mucosal disorders. The aim of this investigation was to study the gastric mucosal electrical potential difference (PD), pH, blood flow and morphology during hypoxia, gastric ischaemia, and gastric ischaemia following inhibition of free...... radical formation with allopurinol. PD and pH were measured simultaneously with an intragastric microelectrode, and the PD values were corrected for the liquid junction potentials created by the intragastric pH variation. Blood flow was measured by the radiolabelled microsphere technique in 18...... anaesthetized dogs. Short general hypoxia and short ischaemia caused reversible declines in PD, increases in pH, and no morphological damage. Ischaemia for 1 h caused a significant decline in PD persistent after reperfusion, an increase in pH, and morphological PD, but after reperfusion PD was normalized. Gross...

Effect of systemic piracetam treatment on flap survival and vascular endothelial growth factor expression after ischemia-reperfusion injury.

Science.gov (United States)

Tuncer, Serhan; Ayhan, Suhan; Findikcioglu, Kemal; Ergun, Hakan; Tuncer, Ilhan

2011-09-01

The effects of piracetam on flap survival, ischemia-reperfusion (I/R) injury, and vascular endothelial growth factor (VEGF) expression were evaluated in this study. Unipedicled epigastric flap model was used in 36 rats and was evaluated within 4 groups. The flap was elevated and untreated in Group 1. Postoperative piracetam treatment was given for 7 days in Group 2. In Group 3, 4 hours of ischemia and 2 hours of reperfusion were applied. I/R was applied to Group 4 and piracetam was given 30 minutes before reperfusion and postoperatively for 7 days. Laser Doppler flowmetry was used to measure blood flow changes. VEGF expression was determined using immunohistochemical methods on tissue samples taken after the completion of 2 hours reperfusion in groups 3 and 4. Flap necrosis was measured on the day 7 in all groups. Blood flow rates did not show significant difference between piracetam treated and untreated I/R groups. Piracetam significantly reduced necrosis area both in ischemic and nonischemic flaps ( P piracetam-treated Group 4 compared with Group 3 ( P = 0.005). This experimental study demonstrates that systemic piracetam treatment improves survival of pedicled flaps, reduces necrosis amounts, and increases VEGF expression in I/R induced flaps. © Thieme Medical Publishers.

Regional blood flow distribution and oxygen metabolism during mesenteric ischemia and congestion.

Science.gov (United States)

Cruz, Ruy J; Garrido, Alejandra G; Ribeiro, Cristiane M F; Harada, Tomoyuki; Rocha-e-Silva, Mauricio

2010-06-01

Acute mesenteric ischemia is a potentially fatal vascular emergency with mortality rates ranging between 60% and 80%. Several studies have extensively examined the hemodynamic and metabolic effects of superior mesenteric artery occlusion. On the other hand, the cardiocirculatory derangement and the tissue damage induced by intestinal outflow obstruction have not been investigated systematically. For these reasons we decided to assess the initial impact of venous mesenteric occlusion on intestinal blood flow distribution, and correlate these findings with other systemic and regional perfusion markers. Fourteen mongrel dogs were subjected to 45 min of superior mesenteric artery (SMAO) or vein occlusion (SMVO), and observed for 120 min after reperfusion. Systemic hemodynamics were evaluated using Swan-Ganz and arterial catheters. Regional blood flow (ultrasonic flow probes), intestinal O(2)-derived variables, and mesenteric-arterial and tonometric-arterial pCO(2) gradients (D(mv-a)pCO(2) and D(t-a)pCO(2)) were also calculated. SMVO was associated with hypotension and low cardiac output. A significant increase in the regional pCO(2) gradients was also observed in both groups during the ischemic period. After reperfusion, a progressive reduction in D(mv-a)pCO(2) occurred in the SMVO group; however, no improvement in D(t-a)pCO(2) was observed. The histopathologic injury scores were 2.7 +/- 0.5 and 4.8 +/- 0.2 for SMAO and SMVO, respectively. SMV occlusion promoted early and significant hemodynamic and metabolic derangement at systemic and regional levels. Additionally, systemic pCO(2) gradient is not a reliable parameter to evaluate the local intestinal oxygenation. Finally, the D(t-a)pCO(2) correlates with histologic changes during intestinal congestion or ischemia. However, minor histologic changes cannot be detected using this methodology. Copyright (c) 2010 Elsevier Inc. All rights reserved.

Reperfusion facilitates reversible disruption of the human blood-brain barrier following acute ischaemic stroke

International Nuclear Information System (INIS)

Liu, Chang; Zhang, Sheng; Yan, Shenqiang; Zhang, Ruiting; Shi, Feina; Lou, Min; Ding, Xinfa; Parsons, Mark

2018-01-01

We aimed to detect early changes of the blood-brain barrier permeability (BBBP) in acute ischaemic stroke (AIS), with or without reperfusion, and find out whether BBBP can predict clinical outcomes. Consecutive AIS patients imaged with computed tomographic perfusion (CTP) before and 24 h after treatment were included. The relative permeability-surface area product (rPS) was calculated within the hypoperfused region (rPS hypo-i ), non-hypoperfused region of ischaemic hemisphere (rPS nonhypo-i ) and their contralateral mirror regions (rPS hypo-c and rPS nonhypo-c ). The changes of rPS were analysed using analysis of variance (ANOVA) with repeated measures. Logistic regression was used to identify independent predictors of unfavourable outcome. Fifty-six patients were included in the analysis, median age was 76 (IQR 62-81) years and 28 (50%) were female. From baseline to 24 h after treatment, rPS hypo-i , rPS nonhypo-i and rPS hypo-c all decreased significantly. The decreases in rPS hypo-i and rPS hypo-c were larger in the reperfusion group than non-reperfusion group. The rPS hypo-i at follow-up was a predictor for unfavourable outcome (OR 1.131; 95% CI 1.018-1.256; P = 0.022). Early disruption of BBB in AIS is reversible, particularly when greater reperfusion is achieved. Elevated BBBP at 24 h after treatment, not the pretreatment BBBP, predicts unfavourable outcome. (orig.)

Reperfusion facilitates reversible disruption of the human blood-brain barrier following acute ischaemic stroke

Energy Technology Data Exchange (ETDEWEB)

Liu, Chang; Zhang, Sheng; Yan, Shenqiang; Zhang, Ruiting; Shi, Feina; Lou, Min [The Second Affiliated Hospital of Zhejiang University, School of Medicine, Department of Neurology, Hangzhou (China); Ding, Xinfa [The Second Affiliated Hospital of Zhejiang University, School of Medicine, Department of Radiology, Hangzhou (China); Parsons, Mark [John Hunter Hospital, University of Newcastle, Department of Neurology, Newcastle (Australia)

2018-02-15

We aimed to detect early changes of the blood-brain barrier permeability (BBBP) in acute ischaemic stroke (AIS), with or without reperfusion, and find out whether BBBP can predict clinical outcomes. Consecutive AIS patients imaged with computed tomographic perfusion (CTP) before and 24 h after treatment were included. The relative permeability-surface area product (rPS) was calculated within the hypoperfused region (rPS{sub hypo-i}), non-hypoperfused region of ischaemic hemisphere (rPS{sub nonhypo-i}) and their contralateral mirror regions (rPS{sub hypo-c} and rPS{sub nonhypo-c}). The changes of rPS were analysed using analysis of variance (ANOVA) with repeated measures. Logistic regression was used to identify independent predictors of unfavourable outcome. Fifty-six patients were included in the analysis, median age was 76 (IQR 62-81) years and 28 (50%) were female. From baseline to 24 h after treatment, rPS{sub hypo-i}, rPS{sub nonhypo-i} and rPS{sub hypo-c} all decreased significantly. The decreases in rPS{sub hypo-i} and rPS{sub hypo-c} were larger in the reperfusion group than non-reperfusion group. The rPS{sub hypo-i} at follow-up was a predictor for unfavourable outcome (OR 1.131; 95% CI 1.018-1.256; P = 0.022). Early disruption of BBB in AIS is reversible, particularly when greater reperfusion is achieved. Elevated BBBP at 24 h after treatment, not the pretreatment BBBP, predicts unfavourable outcome. (orig.)

Two-photon imaging during prolonged middle cerebral artery occlusion in mice reveals recovery of dendritic structure after reperfusion.

Science.gov (United States)

Li, Ping; Murphy, Timothy H

2008-11-12

Filament occlusion of the middle cerebral artery (MCA) is a well accepted animal model of focal ischemia. Advantages of the model are relatively long occlusion times and a large penumbra region that simulates aspects of human stroke. Here, we use two-photon and confocal microscopy in combination with regional measurement of blood flow using laser speckle to assess the spatial relationship between the borders of the MCA ischemic territory and loss of dendrite structure, as well as the effect of reperfusion on dendritic damage in adult YFP (yellow fluorescent protein) and GFP (green fluorescent protein) C57BL/6 transgenic mice with fluorescent (predominantly layer 5) neurons. By examining the spatial extent of dendritic damage, we determined that 60 min of MCA occlusion produced a core with severe structural damage that did not recover after reperfusion (begins approximately 3.8 mm lateral to midline), a reversibly damaged area up to 0.6 mm medial to the core that recovered after reperfusion (penumbra), and a relatively structurally intact area ( approximately 1 mm wide; medial penumbra) with hypoperfusion. Loss of structure was preceded by a single ischemic depolarization 122.1 +/- 10.2 s after occlusion onset. Reperfusion of animals after 60 min of ischemia was not associated with exacerbation of damage (reperfusion injury) and resulted in a significant restoration of blebbed dendritic structure, but only within approximately 0.6 mm lateral of the dendritic damage structural border. In summary, we find that recovery of dendritic structure can occur after reperfusion after even 60 min of ischemia, but is likely restricted to a relatively small penumbra region with partial blood flow or oxygenation.

Acute reperfusion without recanalization

DEFF Research Database (Denmark)

Makris, Nikolaos; Chamard, Leila; Mikkelsen, Irene K

2017-01-01

Acute reperfusion despite persistent arterial occlusion may occur in up to 30% of ischemic stroke patients. Recruitment of leptomeningeal collaterals may explain this phenomenon. Using dynamic susceptibility-contrast perfusion imaging (DSC-PI), we assessed acute changes in collateral flow among...... patients without recanalization. From a multicenter prospective database (I-KNOW), 46 patients with magnetic resonance angiography visible occlusion in whom both reperfusion and recanalization were assessed within 6 h of onset were identified. Maps of collateral flow at arterial, capillary and late venous...... phases were generated from DSC-PI through inter-frame registration, baseline signal subtraction and temporal summation, and graded blind to all other relevant clinical and radiological data using the Higashida scale. Flow direction and the acute evolution of collaterals were evaluated against...

Controlled reperfusion decreased reperfusion induced oxidative stress and evoked inflammatory response in experimental aortic-clamping animal model.

Science.gov (United States)

Jancsó, G; Arató, E; Hardi, P; Nagy, T; Pintér, Ö; Fazekas, G; Gasz, B; Takacs, I; Menyhei, G; Kollar, L; Sínay, L

2016-09-12

Revascularization after long term aortic ischaemia in vascular surgery induces reperfusion injury accompanied with oxidative stress and inflammatory responses. The hypothesis of this study was that the aortic occlusion followed by controlled reperfusion (CR) can reduce the ischaemia-reperfusion injury, the systemic and local inflammatory response induced by oxidative stress.Animal model was used. animals underwent a 4-hour infrarenal aortic occlusion followed by continuous reperfusion. Treated group: animals were treated with CR: after a 4-hour infrarenal aortic occlusion we made CR for 30 minutes with the crystalloid reperfusion solution (blood: crystalloid solution ratio 1:1) on pressure 60 Hgmm. Blood samples were collected different times. The developing oxidative stress was detected by the plasma levels of malondialdehyde, reduced glutathion, thiol groups and superoxide dismutase. The inflammatory response was measured by phorbol myristate acetate-induced leukocyte reactive oxygen species production and detection of change in myeloperoxidase levels. The animals were anaesthetized one week after terminating ligation and biopsy was taken from quadriceps muscle and large parenchymal organs.CR significantly reduced the postischaemic oxydative stress and inflammatory responses in early reperfusion period. Pathophysiological results: The rate of affected muscle fibers by degeneration was significantly higher in the untreated animal group. The infiltration of leukocytes in muscle and parenchymal tissues was significantly lower in the treatedgroup.CR can improve outcome after acute lower-limb ischaemia. The results confirm that CR might be also a potential therapeutic approach in vascular surgery against reperfusion injury in acute limb ischaemia. Supported by OTKA K108596.

Blood rheology of angina pectoris patients with myocardial injury after ischemia reperfusion and its effect on thromboxane B2 levels.

Science.gov (United States)

Wang, Wenlong; Huang, Xiaohui; Sun, Yiyong; Zhang, Jinying

2018-01-01

This study investigated the changes in the blood rheology of patients with angina pectoris and ischemia reperfusion injury and their effect on thromboxane B 2 (TXB 2 ) levels to examine their relationship. Forty patients with unstable angina pectoris who underwent elective percutaneous coronary intervention (PCI) were selected for the unstable angina group (UA group) and forty patients deemed free of coronary heart disease by coronary angiography were selected for the control group. Venous blood samples were drawn from all participants; patients in the UA group had blood drawn 1 day before and 1 day after the PCI procedure. Blood samples were used to analyze blood rheology and examine hemodynamic parameters, at the same time radioimmunoassay was applied to measure the concentrations of serum endothelin-1 (ET-1) and TXB 2 , and an automatic biochemical analyzer was used to detect the content of superoxide dismutase (SOD) and malondialdehyde (MDA). Our results showed the patients in the UA group all presented hyperviscosity; however the levels were higher for the patients in the UA group (after surgery) than for those in the UA group (before surgery). Patients in the control group exhibited normal levels, and the differences among groups were significant in pairwise comparisons (Pangina pectoris and ischemia reperfusion injury. The higher than normal TXB 2 levels can be used as a marker of platelet activation and a reference for clinical risk stratification, thus having great significance for the prevention and treatment of ischemia reperfusion injury and assessment of disease progression.

Acute effects of nicotine and smoking on blood flow, tissue oxygen, and aerobe metabolism of the skin and subcutis

DEFF Research Database (Denmark)

Sørensen, Lars Tue; Jørgensen, Stig; Petersen, Lars J

2009-01-01

BACKGROUND: Nicotine released from tobacco smoke causing reduction in blood flow has been suggested as causative for postoperative wound complications in smokers, but the mechanism remains unknown. MATERIALS AND METHODS: In eight healthy male smokers and eight ex-smokers, the cutaneous and subcut......BACKGROUND: Nicotine released from tobacco smoke causing reduction in blood flow has been suggested as causative for postoperative wound complications in smokers, but the mechanism remains unknown. MATERIALS AND METHODS: In eight healthy male smokers and eight ex-smokers, the cutaneous...... and subcutaneous blood flow (QBF, SqBF) was assessed by Laser Doppler and 133Xe clearance. Tissue oxygen tension (TO(2)) was measured by a LICOX O(2)-electrode. Tissue glucose and lactate (Tgluc, Tlact) were assessed by microdialysis. The parameters were studied after intravenous infusion of 1.0 mg nicotine......, smoking of one cigarette, arterial occlusion, and reperfusion. RESULTS: Nicotine infusion decreased SqBF from 4.2 +/- 2.0 to 3.1 +/- 1.2 mL/100 g tissue/min (P

Incremental balloon deflation following complete resuscitative endovascular balloon occlusion of the aorta results in steep inflection of flow and rapid reperfusion in a large animal model of hemorrhagic shock.

Science.gov (United States)

Davidson, Anders J; Russo, Rachel M; Ferencz, Sarah-Ashley E; Cannon, Jeremy W; Rasmussen, Todd E; Neff, Lucas P; Johnson, M Austin; Williams, Timothy K

2017-07-01

To avoid potential cardiovascular collapse after resuscitative endovascular balloon occlusion of the aorta (REBOA), current guidelines recommend methodically deflating the balloon for 5 minutes to gradually reperfuse distal tissue beds. However, anecdotal evidence suggests that this approach may still result in unpredictable aortic flow rates and hemodynamic instability. We sought to characterize aortic flow dynamics following REBOA as the balloon is deflated in accordance with current practice guidelines. Eight Yorkshire-cross swine were splenectomized, instrumented, and subjected to rapid 25% total blood volume hemorrhage. After 30 minutes of shock, animals received 60 minutes of Zone 1 REBOA with a low-profile REBOA catheter. During subsequent resuscitation with shed blood, the aortic occlusion balloon was gradually deflated in stepwise fashion at the rate of 0.5 mL every 30 seconds until completely deflated. Aortic flow rate and proximal mean arterial pressure (MAP) were measured continuously over the period of balloon deflation. Graded balloon deflation resulted in variable initial return of aortic flow (median, 78 seconds; interquartile range [IQR], 68-105 seconds). A rapid increase in aortic flow during a single-balloon deflation step was observed in all animals (median, 819 mL/min; IQR, 664-1241 mL/min) and corresponded with an immediate decrease in proximal MAP (median, 30 mm Hg; IQR, 14.5-37 mm Hg). Total balloon volume and time to return of flow demonstrated no correlation (r = 0.016). This study is the first to characterize aortic flow during balloon deflation following REBOA. A steep inflection point occurs during balloon deflation that results in an abrupt increase in aortic flow and a concomitant decrease in MAP. Furthermore, the onset of distal aortic flow was inconsistent across study animals and did not correlate with initial balloon volume or relative deflation volume. Future studies to define the factors that affect aortic flow during balloon

Effects of Intestinal Ischaemia-Reperfusion Injury and Splenectomy ...

African Journals Online (AJOL)

The rats were splenectomized and then subjected to either 20minutes or one hour of superior mesenteric artery and collateral supply ischemia and one hour of reperfusion. Control rats were subjected to either 20minutes or one hour of ischemia and one hour of reperfusion only. Blood samples were collected before and ...

Reperfusion of specific cortical areas is associated with improvement in distinct forms of hemispatial neglect.

Science.gov (United States)

Khurshid, Shaan; Trupe, Lydia A; Newhart, Melissa; Davis, Cameron; Molitoris, John J; Medina, Jared; Leigh, Richard; Hillis, Argye E

2012-05-01

To test the hypothesis that restoring blood flow to specific right cortical regions in acute stroke results in improvement in distinct forms of hemispatial neglect distinguished by reference frame: viewer-centered versus stimulus-centered neglect. Twenty five patients with acute right stroke were evaluated at Day 1 and Day 3-5 with a battery of neglect tests and Diffusion- and Perfusion-Weighted MR Imaging. Multivariate linear regression analysis revealed Brodmann areas (BAs) where reperfusion predicted degree of improvement in scores on each type of neglect, independently of reperfusion of other areas, total change in the volume of infarct or hypoperfusion, and age. Reperfusion of dorsal frontoparietal cortex (including BAs 40, 46, and 4) independently predicted improvement in viewer-centered neglect, such as detecting stimuli on left in line cancellation and scene copying (r=.951; p<.0001). Reperfusion of a more ventral temporo-occipital cortex, including right BAs 37, 38, 21 and 18, independently contributed to improvement in stimulus-centered neglect, such as detecting left gaps in circles (r=.926; p<.0001). Reperfusion of right midfusiform gyrus (temporal occipital cortex), change in total volume of ischemia, change in volume of hypoperfusion and age predicted degree of improvement in reading (reduction in "neglect dyslexic" errors; r=.915; p<.0001). Results demonstrate that reperfusing specific cortical regions yields improvement in different types of neglect. Copyright © 2011 Elsevier Srl. All rights reserved.

Change in iron metabolism in rats after renal ischemia/reperfusion injury.

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Guang-Liang Xie

Full Text Available Previous studies have indicated that hepcidin, which can regulate iron efflux by binding to ferroportin-1 (FPN1 and inducing its internalization and degradation, acts as the critical factor in the regulation of iron metabolism. However, it is unknown whether hepcidin is involved in acute renal ischemia/reperfusion injury (IRI. In this study, an IRI rat model was established via right renal excision and blood interruption for 45 min in the left kidney, and iron metabolism indexes were examined to investigate the change in iron metabolism and to analyze the role of hepcidin during IRI. From 1 to 24 h after renal reperfusion, serum creatinine and blood urea nitrogen were found to be time-dependently increased with different degrees of kidney injury. Regular variations in iron metabolism indexes in the blood and kidneys were observed in renal IRI. Renal iron content, serum iron and serum ferritin increased early after reperfusion and then declined. Hepcidin expression in the liver significantly increased early after reperfusion, and its serum concentration increased beginning at 8 h after reperfusion. The splenic iron content decreased significantly in the early stage after reperfusion and then increased time-dependently with increasing reperfusion time, and the hepatic iron content showed a decrease in the early stage after reperfusion. The early decrease of the splenic iron content and hepatic iron content might indicate their contribution to the increase in serum iron in renal IRI. In addition, the duodenal iron content showed time-dependently decreased since 12 h after reperfusion in the IRI groups compared to the control group. Along with the spleen, the duodenum might contribute to the decrease in serum iron in the later stage after reperfusion. The changes in iron metabolism indexes observed in our study demonstrate an iron metabolism disorder in renal IRI, and hepcidin might be involved in maintaining iron homeostasis in renal IRI. These

Comparison of the effects of dexmedetomidine administered at two different times on renal ischemia/reperfusion injury in rats

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Edip Gonullu

2014-05-01

Full Text Available Background and objectives: We investigated the effect of dexmedetomidine on ischemic renal failure in rats. Methods: In the present study, 26 male adult Wistar albino rats weighting 230–300 g were randomly separated into four groups: sham-operated (n = 5, ischemia reperfusion (IR (IR group, n = 7, IR/reperfusion treatment with dexmedetomidine (Dex. R group, n = 7 and IR/pre-ischemic treatment with dexmedetomidine (Dex. I group, n = 7. In the first group, sham operation was achieved and renal clamps were not applied. For the IR group, renal ischemia was induced by occlusion of the bilateral renal arteries and veins for 60 min followed by reperfusion for 24 h. For the Dex. R and Dex. I groups, the same surgical procedure as in the IR group was performed, and dexmedetomidine (100 mcg/kg intraperitoneal was administrated at the 5th min after reperfusion and before ischemia. At the end of reperfusion, blood samples were drawn, the rats were sacrificed, and the left kidney was processed for histopathology. Results: The blood urea nitrogen (BUN levels in groups Dex. R and Dex. I were significantly lower than in the IR group (p = 0.015, p = 0.043, although urine flow was significantly higher in group Dex. R (p = 0.003. The renal histopathological score in the IR group was significantly higher than in the other groups. There was no significant difference between the Dex. R and Dex. I groups. Conclusions: The results were shown that administration of dexmedetomidine reduced the renal IR injury histomorphologically. Administration of dexmedetomidine in the reperfusion period was considered as more effective due to increase in urinary output and decrease in BUN levels. Keywords: Kidney, Ischemia/reperfusion, Dexmedetomidine, Acute renal failure

Effect Of Ischemia-Reperfusion On Healing In Intestinal Anastomosis ...

African Journals Online (AJOL)

The effect of reperfusion injury on the healing of intestinal anastomotic wound directly subjected to ischemia-reperfusion stress was investigated in dogs. Three groups of dogs were utilized for the study. In group A (Control) cranial mesenteric artery and collateral blood supply were isolated but not occluded. In groups B and ...

Rapamycin protects kidney against ischemia reperfusion injury through recruitment of NKT cells.

Science.gov (United States)

Zhang, Chao; Zheng, Long; Li, Long; Wang, Lingyan; Li, Liping; Huang, Shang; Gu, Chenli; Zhang, Lexi; Yang, Cheng; Zhu, Tongyu; Rong, Ruiming

2014-08-19

NKT cells play a protective role in ischemia reperfusion (IR) injury, of which the trafficking in the body and recruitment in injured organs can be influenced by immunosuppressive therapy. Therefore, we investigated the effects of rapamycin on kidneys exposed to IR injury in early stage and on trafficking of NKT cells in a murine model. Balb/c mice were subjected to kidney 30 min ischemia followed by 24 h reperfusion. Rapamycin (2.5 ml/kg) was administered by gavage daily, starting 1 day before the operation. Renal function and histological changes were assessed. The proportion of NKT cells in peripheral blood, spleen and kidney was detected by flow cytometry. The chemokines and corresponding receptor involved in NKT cell trafficking were determined by RT-PCR and flow cytometry respectively. Rapamycin significantly improved renal function and ameliorated histological injury. In rapamycin-treated group, the proportion of NKT cells in spleen was significantly decreased but increased in peripheral blood and kidney. In addition, the CXCR3+ NKT cell in the kidney increased remarkably in the rapamycin-treated group. The chemokines, CXCL9 and CXCL10, as the ligands of CXCR3, were also increased in the rapamycin-treated kidney. Rapamycin may recruit NKT cells from spleen to the IR-induced kidney to ameliorate renal IR injury in the early stage.

Brachial blood flow under relative levels of blood flow restriction is decreased in a nonlinear fashion.

Science.gov (United States)

Mouser, J Grant; Ade, Carl J; Black, Christopher D; Bemben, Debra A; Bemben, Michael G

2018-05-01

Blood flow restriction (BFR), the application of external pressure to occlude venous return and restrict arterial inflow, has been shown to increase muscular size and strength when combined with low-load resistance exercise. BFR in the research setting uses a wide range of pressures, applying a pressure based upon an individual's systolic pressure or a percentage of occlusion pressure; not a directly determined reduction in blood flow. The relationship between relative pressure and blood flow has not been established. To measure blood flow in the arm under relative levels of BFR. Forty-five people (18-40 years old) participated. Arterial occlusion pressure in the right arm was measured using a 5-cm pneumatic cuff. Blood flow in the brachial artery was measured at rest and at pressures between 10% and 90% of occlusion using ultrasound. Blood flow decreased in a nonlinear, stepped fashion. Blood flow decreased at 10% of occlusion and remained constant until decreasing again at 40%, where it remained until 90% of occlusion. The decrease in brachial blood flow is not proportional to the applied relative pressure. The prescription of blood flow restriction should take into account the stimulus provided at each relative level of blood flow. © 2017 Scandinavian Society of Clinical Physiology and Nuclear Medicine. Published by John Wiley & Sons Ltd.

Pharmacological prevention of reperfusion injury in acute myocardial infarction. A potential role for adenosine as a therapeutic agent.

Science.gov (United States)

Quintana, Miguel; Kahan, Thomas; Hjemdahl, Paul

2004-01-01

The concept of reperfusion injury, although first recognized from animal studies, is now recognized as a clinical phenomenon that may result in microvascular damage, no-reflow phenomenon, myocardial stunning, myocardial hibernation and ischemic preconditioning. The final consequence of this event is left ventricular (LV) systolic dysfunction leading to increased morbidity and mortality. The typical clinical case of reperfusion injury occurs in acute myocardial infarction (MI) with ST segment elevation in which an occlusion of a major epicardial coronary artery is followed by recanalization of the artery. This may occur either spontaneously or by means of thrombolysis and/or by primary percutaneous coronary intervention (PCI) with efficient platelet inhibition by aspirin (acetylsalicylic acid), clopidogrel and glycoprotein IIb/IIIa inhibitors. Although the pathophysiology of reperfusion injury is complex, the major role that neutrophils play in this process is well known. Neutrophils generate free radicals, degranulation products, arachidonic acid metabolites and platelet-activating factors that interact with endothelial cells, inducing endothelial injury and neutralization of nitrous oxide vasodilator capacity. Adenosine, through its multi-targeted pharmacological actions, is able to inhibit some of the above-mentioned detrimental effects. The net protective of adenosine in in vivo models of reperfusion injury is the reduction of the infarct size, the improvement of the regional myocardial blood flow and of the regional function of the ischemic area. Additionally, adenosine preserves the post-ischemic coronary flow reserve, coronary blood flow and the post-ischemic regional contractility. In small-scale studies in patients with acute MI, treatment with adenosine has been associated with smaller infarcts, less no-reflow phenomenon and improved LV function. During elective PCI adenosine reduced ST segment shifts, lactate production and ischemic symptoms. During the

Comparison of the effects of dexmedetomidine administered at two different times on renal ischemia/reperfusion injury in rats

Directory of Open Access Journals (Sweden)

Edip Gonullu

2014-06-01

Full Text Available Background and objectives: We investigated the effect of dexmedetomidine on ischemic renal failure in rats. Methods: In the present study, 26 male adult Wistar albino rats weighting 230-300 g were randomly separated into four groups: sham-operated (n = 5, ischemia reperfusion (IR (IR group, n = 7, IR/reperfusion treatment with dexmedetomidine (Dex. R group, n = 7 and IR/pre-ischemic treatment with dexmedetomidine (Dex. I group, n = 7. In the first group, sham operation was achieved and renal clamps were not applied. For the IR group, renal ischemia was induced by occlusion of the bilateral renal arteries and veins for 60 min followed by reperfusion for 24 h. For the Dex. R and Dex. I groups, the same surgical procedure as in the IR group was performed, and dexmedetomidine (100 mcg/kg intraperitoneal was administrated at the 5th min after reperfusion and before ischemia. At the end of reperfusion, blood samples were drawn, the rats were sacrificed, and the left kidney was processed for histopathology. Results: The blood urea nitrogen (BUN levels in groups Dex. R and Dex. I were significantly lower than in the IR group (p = 0.015, p = 0.043, although urine flow was significantly higher in group Dex. R (p = 0.003. The renal histopathological score in the IR group was significantly higher than in the other groups. There was no significant difference between the Dex. R and Dex. I groups. Conclusions: The results were shown that administration of dexmedetomidine reduced the renal IR injury histomorphologically. Administration of dexmedetomidine in the reperfusion period was considered as more effective due to increase in urinary output and decrease in BUN levels.

Role of blood flow and blood flow modifiers in clinical hyperthermia therapy

International Nuclear Information System (INIS)

Olch, A.J.

1986-01-01

A quantitative assessment of the effect of localized magnetic-loop hyperthermia on blood flow was performed on 12 patients (19 tumor studies) using the Xenon-133 clearance method. After it was discovered that blood flow in most of the tumors increased in response to needle injection, a physiologically based, one compartment model was developed that included both a hyperemic (transient) and a steady state component. In the tumors of six patients, increases in blood flow induced by heat were also observed. The same model was used to describe the measured clearance data for both types of hyperemic response. The ability of tumor vessels to respond dynamically to stress and the degree of response may be predictive of tumor heating efficiency and subsequent therapeutic response. Many tumors treated by hyperthermia, therefore, do not reach therapeutic temperatures (42 0 C). One explanation for this may be that some tumors react to thermal stress in a manner similar to normal tissues; i.e., they increase blood flow during hyperthermia in order to dissipate heat. Higher temperatures might be achieved in these heat-resistant tumors by administering vasoconstrictive agents in an effort to reduce blood flow. In the second part of this research study, the extent to which pharmacologic inhibition of local blood flow might allow higher temperatures to develop in normal muscles exposed to localized radiofrequency hyperthermia was determined. It was found that the local muscle temperature rise could be increased by at least 90% in dogs and rabbits with the use of a local vasoconstrictive drug

Aortic blood flow subtraction: an alternative method for measuring total renal blood flow in conscious dogs

DEFF Research Database (Denmark)

Sandgaard, N C F; Andersen, J L; Holstein-Rathlou, N-H

2002-01-01

We have measured total renal blood flow (TRBF) as the difference between signals from ultrasound flow probes implanted around the aorta above and below the renal arteries. The repeatability of the method was investigated by repeated, continuous infusions of angiotensin II and endothelin-1 seven...... arterial blood pressure by 49% and decreased TRBF by 12%, providing an increase in renal vascular resistance of 69%. Dynamic analysis showed autoregulation of renal blood flow in the frequency range ... of TRBF by aortic blood flow subtraction is a practical and reliable method that allows direct comparison of excretory function and renal blood flow from two kidneys. The method also allows direct comparison between TRBF and flow in the caudal aorta....

The Physics of Coronary Blood Flow

CERN Document Server

Zamir, M

2005-01-01

Coronary blood flow is blood flow to the heart for its own metabolic needs. In the most common form of heart disease there is a disruption in this flow because of obstructive disease in the vessels that carry the flow. The subject of coronary blood flow is therefore associated mostly with the pathophysiology of this disease, rarely with dynamics or physics. Yet, the system responsible for coronary blood flow, namely the "coronary circulation," is a highly sophisticated dynamical system in which the dynamics and physics of the flow are as important as the integrity of the conducting vessels. While an obstruction in the conducting vessels is a fairly obvious and clearly visible cause of disruption in coronary blood flow, any discord in the complex dynamics of the system can cause an equally grave, though less conspicuous, disruption in the flow. This book is devoted specifically to the dynamics and physics of coronary blood flow. While relevance to the clinical and pathophysiological issues is clearly maintaine...

Dietary Virgin Olive Oil Reduces Blood Brain Barrier Permeability, Brain Edema, and Brain Injury in Rats Subjected to Ischemia-Reperfusion

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Fatemeh Mohagheghi

2010-01-01

Full Text Available Recent studies suggest that dietary virgin olive oil (VOO reduces hypoxia-reoxygenation injury in rat brain slices. We sought to extend these observations in an in vivo study of rat cerebral ischemia-reperfusion injury. Four groups, each consisting of 18 Wistar rats, were studied. One group (control received saline, while three treatment groups received oral VOO (0.25, 0.5, and 0.75 mL/kg/day, respectively. After 30 days, blood lipid profiles were determined, before a 60-min period of middle cerebral artery occlusion (MCAO. After 24-h reperfusion, neurological deficit scores, infarct volume, brain edema, and blood brain barrier permeability were each assessed in subgroups of six animals drawn from each main group. VOO reduced the LDL/HDL ratio in doses of 0.25, 0.5, and 0.75 mL/kg/day in comparison to the control group (p < 0.05, and offered cerebroprotection from ischemia-reperfusion. For controls vs. doses of 0.25 vs. 0.5 vs. 0.75 mL/kg/day, attenuated corrected infarct volumes were 207.82 ± 34.29 vs. 206.41 ± 26.23 vs. 124.21 ± 14.73 vs. 108.46 ± 31.63 mm3; brain water content of the infarcted hemisphere was 82 ±± 0.25 vs. 81.5 ± 0.56 vs. 80.5 ± 0.22 vs. 80.5 ± 0.34%; and blood brain barrier permeability of the infarcted hemisphere was 11.31 ± 2.67 vs. 9.21 ± 2.28 vs. 5.83 ± 1.6 vs. 4.43 ± 0.93 µg/g tissue (p < 0.05 for measures in doses 0.5 and 0.75 mL/kg/day vs. controls. Oral administration of VOO reduces infarct volume, brain edema, blood brain barrier permeability, and improves neurologic deficit scores after transient MCAO in rats.

Targeting reactive nitrogen species: a promising therapeutic strategy for cerebral ischemia-reperfusion injury.

Science.gov (United States)

Chen, Xing-miao; Chen, Han-sen; Xu, Ming-jing; Shen, Jian-gang

2013-01-01

Ischemic stroke accounts for nearly 80% of stroke cases. Recanalization with thrombolysis is a currently crucial therapeutic strategy for re-building blood supply, but the thrombolytic therapy often companies with cerebral ischemia-reperfusion injury, which are mediated by free radicals. As an important component of free radicals, reactive nitrogen species (RNS), including nitric oxide (NO) and peroxynitrite (ONOO(-)), play important roles in the process of cerebral ischemia-reperfusion injury. Ischemia-reperfusion results in the production of nitric oxide (NO) and peroxynitrite (ONOO(-)) in ischemic brain, which trigger numerous molecular cascades and lead to disruption of the blood brain barrier and exacerbate brain damage. There are few therapeutic strategies available for saving ischemic brains and preventing the subsequent brain damage. Recent evidence suggests that RNS could be a therapeutic target for the treatment of cerebral ischemia-reperfusion injury. Herein, we reviewed the recent progress regarding the roles of RNS in the process of cerebral ischemic-reperfusion injury and discussed the potentials of drug development that target NO and ONOO(-) to treat ischemic stroke. We conclude that modulation for RNS level could be an important therapeutic strategy for preventing cerebral ischemia-reperfusion injury.

Non-invasive pulmonary blood flow analysis and blood pressure mapping derived from 4D flow MRI

Science.gov (United States)

Delles, Michael; Rengier, Fabian; Azad, Yoo-Jin; Bodenstedt, Sebastian; von Tengg-Kobligk, Hendrik; Ley, Sebastian; Unterhinninghofen, Roland; Kauczor, Hans-Ulrich; Dillmann, Rüdiger

2015-03-01

In diagnostics and therapy control of cardiovascular diseases, detailed knowledge about the patient-specific behavior of blood flow and pressure can be essential. The only method capable of measuring complete time-resolved three-dimensional vector fields of the blood flow velocities is velocity-encoded magnetic resonance imaging (MRI), often denoted as 4D flow MRI. Furthermore, relative pressure maps can be computed from this data source, as presented by different groups in recent years. Hence, analysis of blood flow and pressure using 4D flow MRI can be a valuable technique in management of cardiovascular diseases. In order to perform these tasks, all necessary steps in the corresponding process chain can be carried out in our in-house developed software framework MEDIFRAME. In this article, we apply MEDIFRAME for a study of hemodynamics in the pulmonary arteries of five healthy volunteers. The study included measuring vector fields of blood flow velocities by phase-contrast MRI and subsequently computing relative blood pressure maps. We visualized blood flow by streamline depictions and computed characteristic values for the left and the right pulmonary artery (LPA and RPA). In all volunteers, we observed a lower amount of blood flow in the LPA compared to the RPA. Furthermore, we visualized blood pressure maps using volume rendering and generated graphs of pressure differences between the LPA, the RPA and the main pulmonary artery. In most volunteers, blood pressure was increased near to the bifurcation and in the proximal LPA, leading to higher average pressure values in the LPA compared to the RPA.

Effects of hepatic ischemia-reperfusion injury on the blood-brain barrier permeability to [14C] and [13C]sucrose.

Science.gov (United States)

Miah, Mohammad K; Bickel, Ulrich; Mehvar, Reza

2017-12-01

Hepatic encephalopathy that is associated with severe liver failure may compromise the blood-brain barrier (BBB) integrity. However, the effects of less severe liver diseases, in the absence of overt encephalopathy, on the BBB are not well understood. The goal of the current study was to investigate the effects of hepatic ischemia-reperfusion (IR) injury on the BBB tight junction permeability to small, hydrophilic molecules using the widely used [ 14 C]sucrose and recently-proposed alternative [ 13 C]sucrose as markers. Rats were subjected to 20 min of hepatic ischemia or sham surgery, followed by 8 h of reperfusion before administration of a single bolus dose of [ 14 C] or [ 13 C]sucrose and collection of serial (0-30 min) blood and plasma and terminal brain samples. The concentrations of [ 14 C] and [ 13 C]sucrose in the samples were determined by measurement of total radioactivity (nonspecific) and LC-MS/MS (specific), respectively. IR injury significantly increased the blood, plasma, and brain concentrations of both [ 14 C] and [ 13 C]sucrose. However, when the brain concentrations were corrected for their respective area under the blood concentration-time curve, only [ 14 C]sucrose showed significantly higher (30%) BBB permeability values in the IR animals. Because [ 13 C]sucrose is a more specific BBB permeability marker, these data indicate that our animal model of hepatic IR injury does not affect the BBB tight junction permeability to small, hydrophilic molecules. Methodological differences among studies of the effects of liver diseases on the BBB permeability may confound the conclusions of such studies.

Effect of total flavonoids of Radix Ilicis pubescentis on cerebral ischemia reperfusion model

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Xiaoli Yan

2017-03-01

Full Text Available This paper aims to observe the effects of total flavonoids of Radix Ilicis pubescentis on mouse model of cerebral ischemia reperfusion. Mice were orally given different doses of total flavonoids of Radix Ilicis pubescentis 10 d, and were administered once daily. On the tenth day after the administration of 1 h in mice after anesthesia, we used needle to hook the bilateral common carotid artery (CCA for 10 min, with 10 min ischemia reperfusion, 10 min ischemia. Then we restored their blood supply, copy the model of cerebral ischemia reperfusion; We then had all mice reperfused for 24 h, and then took their orbital blood samples and measured blood rheology. We quickly removed the brain, with half of the brain having sagittal incision. Then we fixed the brains and sectioned them to observe the pathological changes of brain cells in the hippocampus and cortex. We also measured the other half sample which was made of brain homogenate of NO, NOS, Na+-K+-, ATP enzyme Mg2+-ATPase and Ca2+-ATPase. Acupuncture needle hook occlusion of bilateral common carotid arteries can successfully establish the model of cerebral ischemia reperfusion. After comparing with the model mice, we concluded that Ilex pubescens flavonoids not only reduce damage to the brain nerve cells in the hippocampus and cortex, but also significantly reduce the content of NO in brain homogenate, the activity of nitric oxide synthase (NOS and increases ATP enzyme activity (P < 0.05, P < 0.01. In this way, cerebral ischemia reperfusion injury is improved. Different dosages of Ilex pubescens flavonoids on mouse cerebral ischemia reperfusion model have good effects.

99mTc-glucarate imaging for the early detection of infarct in partially reperfused canine myocardium

International Nuclear Information System (INIS)

Johnson, Gerald; Okada, Christine C.; Hocherman, Sonia D.; Liu, Zhonglin; Hart, Curtis; Khaw, Ban-An; Okada, Robert D.

2006-01-01

99m Tc-glucarate is an imaging agent developed for the detection of acutely infarcted myocardium. The purposes of the current study were to (1) determine whether 99m Tc-glucarate can detect acute infarct in the setting of only partial minimal reperfusion, (2) study the persistence and time course of scan positivity following coronary occlusion and intravenous tracer injection, (3) assess the ability of 99m Tc-glucarate to determine infarct size, and (4) compare these data with previous results obtained using a 100% reperfusion model. Six dogs underwent left circumflex (LCx) coronary occlusion for 90 min, followed by 10% epicardial blood flow reperfusion. Fifteen mCi (555 MBq) 99m Tc-glucarate was injected intravenously 30 min later. Serial gamma camera images were acquired over 240 min. Microsphere blood flow determinations were performed at baseline, during occlusion, during tracer administration, and just before euthanasia. Ex vivo gamma camera images were obtained. Triphenyltetrazolium chloride (TTC) staining was performed to assess infarct size. Qualitatively, 99m Tc-glucarate images showed a well-defined ''hot spot'' in all six dogs by 30 min after tracer injection (150 min following coronary occlusion), which persisted for 240 min following tracer administration. Quantitatively, there was a significant increase in the LCx/LAD (left anterior descending) counts ratio beginning 10 min after tracer administration (130 min after occlusion), and continuing to 240 min after tracer administration. Tracer retention was 12.0±0.9% for the LAD and 39.0±4.1% for the LCx hot spot zone (p 99m Tc-glucarate injection. The correlation coefficient was 0.90 for infarct size by TTC versus 99m Tc-glucarate. (orig.)

Ultrasound Imaging of Mouse Fetal Intracranial Hemorrhage Due to Ischemia/Reperfusion

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Kenichi Funamoto

2017-05-01

Full Text Available Despite vast improvement in perinatal care during the 30 years, the incidence rate of neonatal encephalopathy remains unchanged without any further Progress towards preventive strategies for the clinical impasse. Antenatal brain injury including fetal intracranial hemorrhage caused by ischemia/reperfusion is known as one of the primary triggers of neonatal injury. However, the mechanisms of antenatal brain injury are poorly understood unless better predictive models of the disease are developed. Here we show a mouse model for fetal intracranial hemorrhage in vivo developed to investigate the actual timing of hypoxia-ischemic events and their related mechanisms of injury. Intrauterine growth restriction mouse fetuses were exposed to ischemia/reperfusion cycles by occluding and opening the uterine and ovarian arteries in the mother. The presence and timing of fetal intracranial hemorrhage caused by the ischemia/reperfusion were measured with histological observation and ultrasound imaging. Protein-restricted diet increased the risk of fetal intracranial hemorrhage. The monitoring of fetal brains by ultrasound B-mode imaging clarified that cerebral hemorrhage in the fetal brain occurred after the second ischemic period. Three-dimensional ultrasound power Doppler imaging visualized the disappearance of main blood flows in the fetal brain. These indicate a breakdown of cerebrovascular autoregulation which causes the fetal intracranial hemorrhage. This study supports the fact that the ischemia/reperfusion triggers cerebral hemorrhage in the fetal brain. The present method enables us to noninvasively create the cerebral hemorrhage in a fetus without directly touching the body but with repeated occlusion and opening of the uterine and ovarian arteries in the mother.

Regional cerebral blood flow in schizophrenia

International Nuclear Information System (INIS)

Mathew, R.J.; Duncan, G.C.; Weinman, M.L.; Barr, D.L.

1982-01-01

Regional cerebral blood flow (rCBF) was measured via xenon133 inhalation technique in 23 patients with schizophrenia and 18 age- and sex-matched controls. The mean blood flow to both hemispheres was found to be lower for the patients. The patients and their controls did not differ on interhemispheric differences in blood flow. There were no differences in rCBF between medicated and unmedicated, subchronic and chronic, and paranoid and nonparanoid patients. Hallucinations were associated with reduced blood flow to several postcentral regions

Regional cerebral blood flow in schizophrenia

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Mathew, R.J.; Duncan, G.C.; Weinman, M.L.; Barr, D.L.

1982-10-01

Regional cerebral blood flow (rCBF) was measured via xenon133 inhalation technique in 23 patients with schizophrenia and 18 age- and sex-matched controls. The mean blood flow to both hemispheres was found to be lower for the patients. The patients and their controls did not differ on interhemispheric differences in blood flow. There were no differences in rCBF between medicated and unmedicated, subchronic and chronic, and paranoid and nonparanoid patients. Hallucinations were associated with reduced blood flow to several postcentral regions.

Measurement of organ blood flow using tritiated water. II. Uterine blood flow in conscious pregnant ewes

International Nuclear Information System (INIS)

Brown, B.W.; Oddy, V.H.; Jones, A.W.

1982-01-01

Total uterine blood flow was measured with a tritiated water (TOH) diffusion method and with radioactive microspheres in six, conscious, pregnant ewes. With continuous infusion of TOH, equilibrium between the TOH concentration in utero-ovarian venous blood and arterial blood was attained within 50 min of the start of the infusion. The concentration of TOH in uterine and foetal tissue and in foetal blood water was the same as that in uterine venous water by 40 min; at this time, the concentration of TOH in the water of amniotic and allantoic fluids was 96% of that in uterine venous blood water. Estimates of total uterine blood flow obtained using TOH were highly correlated with those obtained with microspheres and the corresponding mean flow values obtained with the two techniques did not significantly differ. The percentage of the total uterine blood flow passing through arteriovenous anastomoses ranged from 1.4 to 3.3%

Blood flow and blood volume in a transplanted rat fibrosarcoma

International Nuclear Information System (INIS)

Tozer, G.M.; Morris, C.C.

1990-01-01

Blood flow measurements following i.v. infusion of iodi-antipyrine labelled with 14 C ( 14 C-IAP) and blood volume measurements following i.v. injection of 125 I human serum albumin and 51 Cr-labelled red blood cells were made in a transplanted rat fibrosarcoma for comparison with various normal tissues. The tumour-blood partition co-efficient for 14 C-IAP w as found to be 0.79 ± 0.07 which is similar to most of the normal tissues studied. The solubility of 14 C-IAP in plasma was found to be higher than that in whole blood. Blood flow to tumours 3 was found to be 17.9 ± 4.0 ml blood 100 g tissue -1 xmin -1 . These values were considered to be primarily measurements of nutritive flow. Blood in the tumours was found to occupy around 1% of the tissue space which was similar to that found for normal muscle and skin. There was no direct correlation between % blood volume and blood flow for the different tissues studied. Th haematocrit of blood contained in tumour tissue was calculated to be significantly lower than that of blood contained in the normal tissues. It was suspected that permeability of tumour blood vessel walls to 125 I-HSA could have accounted for this difference. (author). 41 refs.; 2 figs.; 3 tabs

Pathophysiology of mesenteric ischemia/reperfusion: a review Fisiopatologia da isquemia e reperfusão mesentérica: revisão

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Nereide Freire Cerqueira

2005-08-01

Full Text Available During ischemia, the cell structures are progressively damaged, but restoration of the blood flow, paradoxically, intensifies the lesions caused by the ischemia. The mechanisms of ischemia injury and reperfusion (I/R have not been completely defined and many studies have been realized in an attempt to find an ideal therapy for mesenteric I/R. The occlusion and reperfusion of the splanchnic arteries provokes local and systemic alterations principally derived from the release of cytotoxic substances and the interaction between neutrophils and endothelial cells. Substances involved in the process are discussed in the present review, like oxygen-derived free radicals, nitric oxide, transcription factors, complement system, serotonin and pancreatic proteases. The mechanisms of apoptosis, alterations in other organs, therapeutic and evaluation methods are also discussed.Durante a isquemia, as estruturas celulares são progressivamente lesadas, mas a restauração do fluxo sanguíneo, paradoxalmente, pode agravar o dano celular isquêmico. O mecanismo das lesões de isquemia e reperfusão (I/R ainda não foram completamente definidos e muitos estudos têm sido realizados na tentativa de encontrar uma terapia ideal para I/R mesentérica. A oclusão e a reperfusão das artérias esplâncnicas provocam alteracões locais e sistêmicas derivadas principalmente da liberação de substâncias citotóxicas e da interação entre neutrófilos e células endoteliais. As substâncias envolvidas no processo, como radicais livres derivados do oxigênio, óxido nítrico, fatores de transcrição, sistema complemento, serotonina e proteases pancreáticas, são discutidas na presente revisão. Os mecanismos de apoptose, repercussão sistêmica, terapêutica e métodos de avaliação também são discutidos.

Effects Of Ischemic Preconditioning On The Renal Ischemia- Reperfusion Injury

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Anyamanesh S

2003-07-01

Full Text Available  During kidney and other organ transplantation, the organ to be transplanted, must inevitably remain out of the body with little or no blood perfusion at all for a long period of time (ischemia. These events have been suggested to cause the formation of oxygen- derived free radicals (OFR. Reperfusion (reintroduction of blood flow will further exacerbate the initial damage caused by the ischemic insult and may result in the production of free radicals. The aim of this study was to investigate whether induction of brief periods of renal artery occlusion (ischemic pre¬conditioning, IPC can provide protection from the effects of a subsequent period of ischemia and reperfusion (IR in the rat kidney."nMaterials and Methods: In this regard, 28 white, male rats were randomly and equally divided into four groups: Control (sham- operated, IPC alone, IR alone (30 min ischemia followed by 10 min reperfusion, and IPC- IR. Preconditioning involved the sequential clamping of the right renal artery for 5 min and declamping for 5 min for a total of 3 cycles. To demonstrate the effectiveness of IPC regimen, vitamin E as an endogenous antioxidant and an index of lipid peroxidation was measured by HPLC after its extraction from right renal venous plasma and right renal tissue."nResults: Results of this study showed that the amount of vitamin E of renal tissue and venous plasma in the IR group had a significant decrease when compared to the control group (P< 0.0001. Whereas the amount of this vitamin in both renal tissue and venous plasma of the IPC- IR group was significantly higher than that in the IR group (P< 0.0001, but did not show any significant difference with the control group."nConclusion: In this study, preconditioning method prevented the reduction of the endogenous antioxidant (Vit. E in encountering the following sustained ischemic insult. Therefore, we suggest that ischemic preconditioning can be used to protect the Vit. E level of kidney from its

Radioisotopic flow scanning for portal blood flow and portal hypertension

International Nuclear Information System (INIS)

Hesdorffer, C.S.; Bezwoda, W.R.; Danilewitz, M.D.; Esser, J.D.; Tobias, M.

1987-01-01

The use of a simple, noninvasive, isotope scanning technique for the determination of relative portal blood flow and detection of portal hypertension is described. Using this technique the presence of portal hypertension was demonstrated in seven of nine patients known to have elevated portal venous pressure. By contrast, esophageal varices were demonstrated in only five of these patients, illustrating the potential value of the method. Furthermore, this technique has been adapted to the study of portal blood flow in patients with myeloproliferative disorders with splenomegaly but without disturbances in hepatic architecture. Results demonstrate that the high relative splenic flow resulting from the presence of splenomegaly may in turn be associated with elevated relative portal blood flow and portal hypertension. The theoretic reasons for the development of flow-related portal hypertension and its relationship to splenic blood flow are discussed

The cardioprotective efficacy of TVP1022 against ischemia/reperfusion injury and cardiac remodeling in rats.

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Malka, Assaf; Ertracht, Offir; Bachner-Hinenzon, Noa; Reiter, Irina; Binah, Ofer

2016-12-01

Following acute myocardial infarction (MI), early and successful reperfusion is the most effective strategy for reducing infarct size and improving the clinical outcome. However, immediate restoration of blood flow to the ischemic zone results in myocardial damage, defined as "reperfusion-injury". Whereas we previously reported that TVP1022 (the S-isomer of rasagiline, FDA-approved anti-Parkinson drug) decreased infarct size 24 h post ischemia reperfusion (I/R) in rats, in this study we investigated the chronic cardioprotective efficacy of TVP1022 14 days post-I/R. To simulate the clinical settings of acute MI followed by reperfusion therapy, we employed a rat model of left anterior descending artery occlusion for 30 min followed by reperfusion and a follow-up for 14 days. TVP1022 was initially administered postocclusion-prereperfusion, followed by chronic daily administrations. Cardiac performance and remodeling were evaluated using customary and advanced echocardiographic methods, hemodynamic measurements by Millar Mikro-Tip ® catheter, and histopathological techniques. TVP1022 administration markedly decreased the remodeling process as illustrated by attenuation of left ventricular enlargement and cardiac hypertrophy (both at the whole heart and the cellular level). Furthermore, TVP1022 inhibited cardiac fibrosis and reduced ventricular BNP levels. Functionally, TVP1022 treatment preserved cardiac wall motion. Specifically, the echocardiographic and most of the direct hemodynamic measures were pronouncedly improved by TVP1022. Collectively, these findings indicate that TVP1022 provides prominent cardioprotection against I/R injury and post-MI remodeling in this I/R model.

Nutrient and nonnutrient renal blood flow

International Nuclear Information System (INIS)

Young, J.S.; Passmore, J.C.; Hartupee, D.A.; Baker, C.H.

1990-01-01

The role of prostaglandins in the distribution of total renal blood flow (TRBF) between nutrient and nonnutrient compartments was investigated in anesthetized mongrel dogs. Renal blood flow distribution was assessed by the xenon 133 freeze-dissection technique and by rubidium 86 extraction after ibuprofen treatment. Ibuprofen (13 mg/kg) significantly decreased TRBF by 16.3% +/- 1.2% (mean +/- SEM electromagnetic flow probe; p less than 0.005), but did not alter blood flows to the outer cortex (3.7 vs 4.3 ml/min per gram), the inner cortex (2.6 vs 2.7 ml/min per gram), and the other medulla (1.5 vs 1.5 ml/min per gram), which suggests a decrease in nonnutrient flow. In a separate group of animals the effect of reduced blood flow on the nutrient and nonnutrient components was determined by mechanically reducing renal arterial blood flow by 48%. Unlike the ibuprofen group, nutrient blood flows were proportionally reduced with the mechanical decrease in TRBF in the outer cortex (1.9 ml/min per gram, p less than 0.05), the inner cortex (1.4 ml/min per gram, p less than 0.05), and the outer medulla (0.8 ml/min per gram, p less than 0.01). These results indicate no shift between nutrient and nonnutrient compartments. Nutrient and nonnutrient renal blood flows of the left kidney were also determined by 86Rb extraction. After ibuprofen treatment, nonextracted 86Rb decreased to 12.1% from the control value of 15.6% (p less than 0.05). Mechanical reduction of TRBF did not significantly decrease the proportion of unextracted 86Rb (18.7%)

Microsphere estimates of blood flow: Methodological considerations

International Nuclear Information System (INIS)

von Ritter, C.; Hinder, R.A.; Womack, W.; Bauerfeind, P.; Fimmel, C.J.; Kvietys, P.R.; Granger, D.N.; Blum, A.L.

1988-01-01

The microsphere technique is a standard method for measuring blood flow in experimental animals. Sporadic reports have appeared outlining the limitations of this method. In this study the authors have systematically assessed the effect of blood withdrawals for reference sampling, microsphere numbers, and anesthesia on blood flow estimates using radioactive microspheres in dogs. Experiments were performed on 18 conscious and 12 anesthetized dogs. Four blood flow estimates were performed over 120 min using 1 x 10 6 microspheres each time. The effects of excessive numbers of microspheres pentobarbital sodium anesthesia, and replacement of volume loss for reference samples with dextran 70 were assessed. In both conscious and anesthetized dogs a progressive decrease in gastric mucosal blood flow and cardiac output was observed over 120 min. This was also observed in the pancreas in conscious dogs. The major factor responsible for these changes was the volume loss due to the reference sample withdrawals. Replacement of the withdrawn blood with dextran 70 led to stable blood flows to all organs. The injection of excessive numbers of microspheres did not modify hemodynamics to a greater extent than did the injection of 4 million microspheres. Anesthesia exerted no influence on blood flow other than raising coronary flow. The authors conclude that although blood flow to the gastric mucosa and the pancreas is sensitive to the minor hemodynamic changes associated with the microsphere technique, replacement of volume loss for reference samples ensures stable blood flow to all organs over a 120-min period

Postconditioning attenuates acute intestinal ischemia–reperfusion injury

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Ilker Sengul

2013-03-01

Full Text Available The aim of this study was to test the hypothesis that postconditioning (POC would reduce the detrimental effects of the acute intestinal ischemia–reperfusion (I/R compared to those of the abrupt onset of reperfusion. POC has a protective effect on intestinal I/R injury by inhibiting events in the early minutes of reperfusion in rats. Twenty-four Wistar–Albino rats were subjected to the occlusion of superior mesenteric artery for 30 minutes, then reperfused for 120 minutes, and randomized to the four different modalities of POC: (1 control (no intervention; (2 POC-3 (three cycles of 10 seconds of reperfusion–reocclusion, 1 minute total intervention; (3 POC-6 (six cycles of 10 seconds of reperfusion–reocclusion, 2 minutes total intervention; and (4 sham operation (laparotomy only. The arterial blood samples [0.3 mL total creatine kinase (CK and 0.6 mL malondialdehyde (MDA] and the intestinal mucosal MDA were collected from each after reperfusion. POC, especially POC-6, was effective in attenuating postischemic pathology by decreasing the intestinal tissue MDA levels, serum total CK activity, inflammation, and total histopathological injury scores. POC exerted a protective effect on the intestinal mucosa by reducing the mesenteric oxidant generation, lipid peroxidation, and neutrophil accumulation. The six-cycle algorithm demonstrated the best protection.

Stimulation of the sphenopalatine ganglion induces reperfusion and blood-brain barrier protection in the photothrombotic stroke model.

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Haviv Levi

Full Text Available The treatment of stroke remains a challenge. Animal studies showing that electrical stimulation of the sphenopalatine ganglion (SPG exerts beneficial effects in the treatment of stroke have led to the initiation of clinical studies. However, the detailed effects of SPG stimulation on the injured brain are not known.The effect of acute SPG stimulation was studied by direct vascular imaging, fluorescent angiography and laser Doppler flowmetry in the sensory motor cortex of the anaesthetized rat. Focal cerebral ischemia was induced by the rose bengal (RB photothrombosis method. In chronic experiments, SPG stimulation, starting 15 min or 24 h after photothrombosis, was given for 3 h per day on four consecutive days. Structural damage was assessed using histological and immunohistochemical methods. Cortical functions were assessed by quantitative analysis of epidural electro-corticographic (ECoG activity continuously recorded in behaving animals.Stimulation induced intensity- and duration-dependent vasodilation and increased cerebral blood flow in both healthy and photothrombotic brains. In SPG-stimulated rats both blood brain-barrier (BBB opening, pathological brain activity and lesion volume were attenuated compared to untreated stroke animals, with no apparent difference in the glial response surrounding the necrotic lesion.SPG-stimulation in rats induces vasodilation of cortical arterioles, partial reperfusion of the ischemic lesion, and normalization of brain functions with reduced BBB dysfunction and stroke volume. These findings support the potential therapeutic effect of SPG stimulation in focal cerebral ischemia even when applied 24 h after stroke onset and thus may extend the therapeutic window of currently administered stroke medications.

Modified Beer-Lambert law for blood flow.

Science.gov (United States)

Baker, Wesley B; Parthasarathy, Ashwin B; Busch, David R; Mesquita, Rickson C; Greenberg, Joel H; Yodh, A G

2014-11-01

We develop and validate a Modified Beer-Lambert law for blood flow based on diffuse correlation spectroscopy (DCS) measurements. The new formulation enables blood flow monitoring from temporal intensity autocorrelation function data taken at single or multiple delay-times. Consequentially, the speed of the optical blood flow measurement can be substantially increased. The scheme facilitates blood flow monitoring of highly scattering tissues in geometries wherein light propagation is diffusive or non-diffusive, and it is particularly well-suited for utilization with pressure measurement paradigms that employ differential flow signals to reduce contributions of superficial tissues.

{sup 99m}Tc-glucarate imaging for the early detection of infarct in partially reperfused canine myocardium

Energy Technology Data Exchange (ETDEWEB)

Johnson, Gerald; Okada, Christine C.; Hocherman, Sonia D. [University of Oklahoma Health Sciences Center, Tulsa, OK (United States); Liu, Zhonglin [University of Arizona, Tucson, AZ (United States); Hart, Curtis [University of Texas, San Antonio, TX (United States); Khaw, Ban-An [Northeastern University, Boston, MA (United States); Okada, Robert D. [University of Oklahoma Health Sciences Center, Tulsa, OK (United States); University of Tulsa, Department of Biology, Tulsa, OK (United States)

2006-03-15

{sup 99m}Tc-glucarate is an imaging agent developed for the detection of acutely infarcted myocardium. The purposes of the current study were to (1) determine whether {sup 99m}Tc-glucarate can detect acute infarct in the setting of only partial minimal reperfusion, (2) study the persistence and time course of scan positivity following coronary occlusion and intravenous tracer injection, (3) assess the ability of {sup 99m}Tc-glucarate to determine infarct size, and (4) compare these data with previous results obtained using a 100% reperfusion model. Six dogs underwent left circumflex (LCx) coronary occlusion for 90 min, followed by 10% epicardial blood flow reperfusion. Fifteen mCi (555 MBq) {sup 99m}Tc-glucarate was injected intravenously 30 min later. Serial gamma camera images were acquired over 240 min. Microsphere blood flow determinations were performed at baseline, during occlusion, during tracer administration, and just before euthanasia. Ex vivo gamma camera images were obtained. Triphenyltetrazolium chloride (TTC) staining was performed to assess infarct size. Qualitatively, {sup 99m}Tc-glucarate images showed a well-defined ''hot spot'' in all six dogs by 30 min after tracer injection (150 min following coronary occlusion), which persisted for 240 min following tracer administration. Quantitatively, there was a significant increase in the LCx/LAD (left anterior descending) counts ratio beginning 10 min after tracer administration (130 min after occlusion), and continuing to 240 min after tracer administration. Tracer retention was 12.0{+-}0.9% for the LAD and 39.0{+-}4.1% for the LCx hot spot zone (p<0.05) at 240 min after {sup 99m}Tc-glucarate injection. The correlation coefficient was 0.90 for infarct size by TTC versus {sup 99m}Tc-glucarate. (orig.)

Blood cell interactions and segregation in flow.

Science.gov (United States)

Munn, Lance L; Dupin, Michael M

2008-04-01

For more than a century, pioneering researchers have been using novel experimental and computational approaches to probe the mysteries of blood flow. Thanks to their efforts, we know that blood cells generally prefer to migrate to the axis of flow, that red and white cells segregate in flow, and that cell deformability and their tendency to reversibly aggregate contribute to the non-Newtonian nature of this unique fluid. All of these properties have beneficial physiological consequences, allowing blood to perform a variety of critical functions. Our current understanding of these unusual flow properties of blood have been made possible by the ingenuity and diligence of a number of researchers, including Harry Goldsmith, who developed novel technologies to visualize and quantify the flow of blood at the level of individual cells. Here we summarize efforts in our lab to continue this tradition and to further our understanding of how blood cells interact with each other and with the blood vessel wall.

Protective effects of Rosmarinic acid against renal ischaemia/reperfusion injury in rats

International Nuclear Information System (INIS)

Ozturk, H.; Ozturk, H.; Terzi, E.H.

2014-01-01

Objective: To investigate the potential protective effects of Rosmarinic acid (RA) on rats exposed to ischaemia/reperfusion renal injury. Methods: The prospective study was conducted at Abant Izzet Baysal University, Turkey, and comprised 21 male Spraque Dawley rats weighing 250-270g each. They were divided into three equal groups. Unilaterally nephrectomised rats were subjected to 60 minutes of left renal ischaemia followed by 60 minutes of reperfusion. Group 1 had shamoperated animals; group 2 had ischaemia/reperfusion untreated animals; and group 3 had ischaemia/reperfusion animals treated with rosmarinic acid. Serum creatinine, blood urea nitrogen, tissue malondialdehyde, glutathione peroxidase, superoxide dismutase and myeloperoxidase (MPO) activities, and light microscopic findings were evaluated. SPSS 17 was used for statistical analysis. Results: Treatment of rats with rosmarinic acid produced a reduction in the serum levels of creatinine and blood urea nitrogen compared to the other groups. However, no statistically significant difference was found. The levels of malondialdehyde and myeloperoxidase were decreased in the renal tissue of group 3, while glutathione peroxidose and superoxide dismutase levels remained unchanged. The injury score decreased in the treatment group rats compared to the untreated group. Rosmarinic acid significantly decreased focal glomerular necrosis, dilatation of Bowman's capsule, degeneration of tubular epithelium, necrosis in tubular epithelium, and tubular dilatation. Conclusions: Rosmarinic acid prevented ischaemia/reperfusion injury in the kidneys by decreasing oxidative stress. (author)

The role of indoleamine 2,3 dioxygenase in beneficial effects of stem cells in hind limb ischemia reperfusion injury.

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Mohamad Masoumy

Full Text Available Ischemia-Reperfusion (IR injury of limb remains a significant clinical problem causing secondary complications and restricting clinical recovery, despite rapid restoration of blood flow and successful surgery. In an attempt to further improve post ischemic tissue repair, we investigated the effect of a local administration of bone marrow derived stem cells (BMDSCs in the presence or absence of immune-regulatory enzyme, IDO, in a murine model. A whole limb warm ischemia-reperfusion model was developed using IDO sufficient (WT and deficient (KO mice with C57/BL6 background. Twenty-four hours after injury, 5 × 105 cells (5×105 cells/200 µL of PBS solution BMDSCs (Sca1 + cells were injected intramuscularly while the control group received just the vehicle buffer (PBS. Forty-eight to seventy-two hours after limb BMDSC injection, recovery status including the ratio of intrinsic paw function between affected and normal paws, general mobility, and inflammatory responses were measured using video micrometery, flow cytometry, and immunohistochemistry techniques. Additionally, MRI/MRA studies were performed to further study the inflammatory response between groups and to confirm reconstitution of blood flow after ischemia. For the first time, our data, showed that IDO may potentially represent a partial role in triggering the beneficial effects of BMDSCs in faster recovery and protection against structural changes and cellular damage in a hind limb IR injury setting (P = 0.00058.

Glial and neuronal control of brain blood flow

DEFF Research Database (Denmark)

Attwell, David; Buchan, Alastair M; Charpak, Serge

2010-01-01

Blood flow in the brain is regulated by neurons and astrocytes. Knowledge of how these cells control blood flow is crucial for understanding how neural computation is powered, for interpreting functional imaging scans of brains, and for developing treatments for neurological disorders. It is now...... recognized that neurotransmitter-mediated signalling has a key role in regulating cerebral blood flow, that much of this control is mediated by astrocytes, that oxygen modulates blood flow regulation, and that blood flow may be controlled by capillaries as well as by arterioles. These conceptual shifts...

The effect of partial portal decompression on portal blood flow and effective hepatic blood flow in man: a prospective study.

Science.gov (United States)

Rosemurgy, A S; McAllister, E W; Godellas, C V; Goode, S E; Albrink, M H; Fabri, P J

1995-12-01

With the advent of transjugular intrahepatic porta-systemic stent shunt and the wider application of the surgically placed small diameter prosthetic H-graft portacaval shunt (HGPCS), partial portal decompression in the treatment of portal hypertension has received increased attention. The clinical results supporting the use of partial portal decompression are its low incidence of variceal rehemorrhage due to decreased portal pressures and its low rate of hepatic failure, possibly due to maintenance of blood flow to the liver. Surprisingly, nothing is known about changes in portal hemodynamics and effective hepatic blood flow following partial portal decompression. To prospectively evaluate changes in portal hemodynamics and effective hepatic blood flow brought about by partial portal decompression, the following were determined in seven patients undergoing HGPCS: intraoperative pre- and postshunt portal vein pressures and portal vein-inferior vena cava pressure gradients, intraoperative pre- and postshunt portal vein flow, and pre- and postoperative effective hepatic blood flow. With HGPCS, portal vein pressures and portal vein-inferior vena cava pressure gradients decreased significantly, although portal pressures remained above normal. In contrast to the significant decreases in portal pressures, portal vein blood flow and effective hepatic blood flow do not decrease significantly. Changes in portal vein pressures and portal vein-inferior vena cava pressure gradients are great when compared to changes in portal vein flow and effective hepatic blood flow. Reduction of portal hypertension with concomitant maintenance of hepatic blood flow may explain why hepatic dysfunction is avoided following partial portal decompression.

Blood flow autoregulation in pedicled flaps

DEFF Research Database (Denmark)

Bonde, Christian T; Holstein-Rathlou, Niels-Henrik; Elberg, Jens J

2009-01-01

was to evaluate if, and to what extent, a tissue flap could compensate a reduction in blood flow due to an acute constriction of the feed artery. Further, we wanted to examine the possible role of smooth muscle L-type calcium channels in the autoregulatory mechanism by pharmacological intervention with the L......, the flow in the pedicle was reduced and the flow was recorded. RESULTS: The flaps showed a strong autoregulatory response with complete compensation for flow reductions of up to 70-80%. Infusion of nimodipine caused a 28+/-10% increase in blood flow and removed the autoregulation. Papaverine caused...... a further increase in blood flow by 61+/-19%. The time control experiments proved that the experimental procedure was reproducible and stable over time. CONCLUSIONS: A tissue flap can nearly completely compensate for repeated flow reductions of up to 70-80%. This is due to a decrease in the peripheral...

Blood flow patterns underlie developmental heart defects.

Science.gov (United States)

Midgett, Madeline; Thornburg, Kent; Rugonyi, Sandra

2017-03-01

Although cardiac malformations at birth are typically associated with genetic anomalies, blood flow dynamics also play a crucial role in heart formation. However, the relationship between blood flow patterns in the early embryo and later cardiovascular malformation has not been determined. We used the chicken embryo model to quantify the extent to which anomalous blood flow patterns predict cardiac defects that resemble those in humans and found that restricting either the inflow to the heart or the outflow led to reproducible abnormalities with a dose-response type relationship between blood flow stimuli and the expression of cardiac phenotypes. Constricting the outflow tract by 10-35% led predominantly to ventricular septal defects, whereas constricting by 35-60% most often led to double outlet right ventricle. Ligation of the vitelline vein caused mostly pharyngeal arch artery malformations. We show that both cardiac inflow reduction and graded outflow constriction strongly influence the development of specific and persistent abnormal cardiac structure and function. Moreover, the hemodynamic-associated cardiac defects recapitulate those caused by genetic disorders. Thus our data demonstrate the importance of investigating embryonic blood flow conditions to understand the root causes of congenital heart disease as a prerequisite to future prevention and treatment. NEW & NOTEWORTHY Congenital heart defects result from genetic anomalies, teratogen exposure, and altered blood flow during embryonic development. We show here a novel "dose-response" type relationship between the level of blood flow alteration and manifestation of specific cardiac phenotypes. We speculate that abnormal blood flow may frequently underlie congenital heart defects. Copyright © 2017 the American Physiological Society.

CURRENT REPERFUSION THERAPY POSSIBILITIES IN MYOCARDIAL INFARCTION AND ISCHEMIC STROKE

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E. V. Konstantinova

2015-01-01

Full Text Available Myocardial infarction and ischemic stroke remain to be of the greatest medical and social importance because of their high prevalence, disability, and mortality rates. Intractable thrombotic occlusion of the respective artery leads to the formation of an ischemic lesion focus in the tissue of the heart or brain. Emergency reperfusion serves to decrease a necrotic focus, makes its formation reversible, and reduces patient death rates. The paper considers main reperfusion therapy lines: medical (with thrombolytic drugs and mechanical (with primary interventions one and their combination in treating patients with acute myocardial and cerebral ischemia. Each reperfusion procedure is discussed in view of its advantages, disadvantages, available guidelines, and possibilities of real clinical practice. Tenecteplase is assessed in terms of its efficacy, safety, and capacities for bolus administration, which allows its use at any hospital and at the pre-hospital stage. Prehospital thrombolysis permits reperfusion therapy to bring much closer to the patient and therefore aids in reducing time to reperfusion and in salvaging as much the myocardial volume as possible. The rapidest recovery of myocardial and cerebral perfusion results in a decreased necrotic area and both improved immediate and late prognosis. The results of randomized clinical trials studying the possibilities of the medical and mechanical methods to restore blood flow are analyzed in the context of evidence-based medicine. The reason why despite the available contraindications, limited efficiency, and the risk of hemorrhagic complications, thrombolytic therapy remains the method of choice for prehospital reperfusion, an alternative to primary percutaneous coronary intervention (PCI if it cannot be carried out in patients with myocardial infarction at the stated time, and the only treatment ischemic stroke treatment that has proven its efficiency and safety in clinical trials is under

Three-dimensional imaging of absolute blood flow velocity and blood vessel position under low blood flow velocity based on Doppler signal information included in scattered light from red blood cells

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Kyoden, Tomoaki; Akiguchi, Shunsuke; Tajiri, Tomoki; Andoh, Tsugunobu; Hachiga, Tadashi

2017-11-01

The development of a system for in vivo visualization of occluded distal blood vessels for diabetic patients is the main target of our research. We herein describe two-beam multipoint laser Doppler velocimetry (MLDV), which measures the instantaneous multipoint flow velocity and can be used to observe the blood flow velocity in peripheral blood vessels. By including a motorized stage to shift the measurement points horizontally and in the depth direction while measuring the velocity, the path of the blood vessel in the skin could be observed using blood flow velocity in three-dimensional space. The relationship of the signal power density between the blood vessel and the surrounding tissues was shown and helped us identify the position of the blood vessel. Two-beam MLDV can be used to simultaneously determine the absolute blood flow velocity distribution and identify the blood vessel position in skin.

Intravenous Infusion of Magnesium Chloride Improves Epicenter Blood Flow during the Acute Stage of Contusive Spinal Cord Injury in Rats

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Muradov, Johongir M.

2013-01-01

Abstract Vasospasm, hemorrhage, and loss of microvessels at the site of contusive or compressive spinal cord injury lead to infarction and initiate secondary degeneration. Here, we used intravenous injection of endothelial-binding lectin followed by histology to show that the number of perfused microvessels at the injury site is decreased by 80–90% as early as 20 min following a moderate T9 contusion in adult female rats. Hemorrhage within the spinal cord also was maximal at 20 min, consistent with its vasoconstrictive actions in the central nervous system (CNS). Microvascular blood flow recovered to up to 50% of normal volume in the injury penumbra by 6 h, but not at the epicenter. A comparison with an endothelial cell marker suggested that many microvessels fail to be reperfused up to 48 h post-injury. The ischemia was probably caused by vasospasm of vessels penetrating the parenchyma, because repeated Doppler measurements over the spinal cord showed a doubling of total blood flow over the first 12 h. Moreover, intravenous infusion of magnesium chloride, used clinically to treat CNS vasospasm, greatly improved the number of perfused microvessels at 24 and 48 h. The magnesium treatment seemed safe as it did not increase hemorrhage, despite the improved parenchymal blood flow. However, the treatment did not reduce acute microvessel, motor neuron or oligodendrocyte loss, and when infused for 7 days did not affect functional recovery or spared epicenter white matter over a 4 week period. These data suggest that microvascular blood flow can be restored with a clinically relevant treatment following spinal cord injury. PMID:23302047

Ischemia-reperfusion injury in the isolated rat lung. Role of flow and endogenous leukocytes.

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Seibert, A F; Haynes, J; Taylor, A

1993-02-01

Microvascular lung injury caused by ischemia-reperfusion (IR) may occur via leukocyte-dependent and leukocyte-independent pathways. Leukocyte-endothelial adhesion may be a rate-limiting step in IR lung injury. Leukocyte adhesion to microvascular endothelium occurs when the attractant forces between leukocyte and endothelium are greater than the kinetic energy of the leukocyte and the vascular wall shear rate. We hypothesized (1) that isolated, buffer-perfused rat lungs are not free of endogenous leukocytes, (2) that endogenous leukocytes contribute to IR-induced microvascular injury as measured by the capillary filtration coefficient (Kfc), and (3) that a reduction of perfusate flow rate would potentiate leukocyte-dependent IR injury. Sixty lungs were divided into four groups: (1) low-flow controls, (2) high-flow controls, (3) low-flow IR, and (4) high-flow IR. Microvascular injury was linearly related to baseline perfusate leukocyte concentrations at both low (r = 0.78) and high (r = 0.82) flow rates. Kfc in the high-flow IR group (0.58 +/- 0.03 ml/min/cm H2O/100 g) was less (p Kfc in the low-flow IR group (0.82 +/- 0.07), and in both groups Kfc values were significantly greater than low-flow (0.34 +/- 0.03) and high-flow (0.31 +/- 0.01) control Kfc values after 75 min. Retention of leukocytes in the lung, evaluated by a tissue myeloperoxidase assay, was greatest in the low-flow IR group. We conclude (1) that isolated, buffer-perfused rat lungs contain significant quantities of leukocytes and that these leukocytes contribute to IR lung injury, and (2) that IR-induced microvascular injury is potentiated by low flow.

Blood flow determinations utilizing digital densitometry

International Nuclear Information System (INIS)

Lois, F.; Mankovich, N.J.; Gomes, A.S.

1987-01-01

A method of obtaining relative and absolute blood flow measurements from digital densitometry was evaluated with a simulated vessel phantom and a hydrodynamic model. A digital vascular imaging system capable of acquisition in 512 2 and 1024 2 mode was used. Relative and absolute blood flow were measured using parameters derived from the densitometric curve. Since application of densitometric data to absolute flow measurements requires the vessel diameter, an algorithm for vessel size determination was created. Gray scale changes were demonstrated to be linearly related to contrast concentration. The variance of vessel size determination was significantly different in all combinations of 1024 2 and 512 2 imaging with 15 cm or 35 cm field size. The error in vessel size determination was significantly less using the larger 1024 2 matrix and the smaller 15 cm image intensifier field size, as shown by the smaller variance. In relative flow determinations, there was good correlation between the flow and four parameters of the densitometric curve with no significant differences between 512 2 and 1024 2 imaging. Absolute flow determinations had slightly lower correlation to actual flow but were not significantly different from relative flow determinations. Relative and absolute blood flow determinations can be performed adequately with either 512 2 or 1024 2 imaging. The increased accuracy in vessel size determination with 1024 2 imaging makes this high resolution system potentially perferable to determine absolute blood flow. (orig.)

Thymoquinone protects end organs from abdominal aorta ischemia/reperfusion injury in a rat model.

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Aydin, Mehmet Salih; Kocarslan, Aydemir; Kocarslan, Sezen; Kucuk, Ahmet; Eser, İrfan; Sezen, Hatice; Buyukfirat, Evren; Hazar, Abdussemet

2015-01-01

Previous studies have demonstrated that thymoquinone has protective effects against ischemia reperfusion injury to various organs like lungs, kidneys and liver in different experimental models. We aimed to determine whether thymoquinone has favorable effects on lung, renal, heart tissues and oxidative stress in abdominal aorta ischemia-reperfusion injury. Thirty rats were divided into three groups as sham (n=10), control (n=10) and thymoquinone (TQ) treatment group (n=10). Control and TQ-treatment groups underwent abdominal aorta ischemia for 45 minutes followed by a 120-min period of reperfusion. In the TQ-treatment group, thymoquinone was given 5 minutes. before reperfusion at a dose of 20 mg/kg via an intraperitoneal route. Total antioxidant capacity, total oxidative status (TOS), and oxidative stress index (OSI) in blood serum were measured and lung, kidney, and heart tissue histopathology were evaluated with light microscopy. Total oxidative status and oxidative stress index activity in blood samples were statistically higher in the control group compared to the sham and TQ-treatment groups (POSI). Control group injury scores were statistically higher compared to sham and TQ-treatment groups (Pmodel.

Bone blood flow and metabolism in humans

DEFF Research Database (Denmark)

Heinonen, Ilkka; Kemppainen, Jukka; Kaskinoro, Kimmo

2012-01-01

Human bone blood flow and metabolism during physical exercise remains poorly characterised. In the present study we measured femoral bone blood flow and glucose uptake in young healthy subjects by positron emission tomography in three separate protocols. In six women, blood flow was measured...... in femoral bone at rest and during one leg intermittent isometric exercise with increasing exercise intensities. In nine men, blood flow in femur was determined at rest and during dynamic one leg exercise, and two other physiological perturbations: moderate systemic hypoxia (14 O(2) ) at rest and during...... exercise, and during intra-femoral infusion of high-dose adenosine. Bone glucose uptake was measured at rest and during dynamic one leg exercise in five men. The results indicate that isometric exercise increased femoral bone blood flow from rest (1.8 ± 0.6 ml/100g/min) to low intensity exercise (4.1 ± 1...

Nasal mucosal blood flow after intranasal allergen challenge

International Nuclear Information System (INIS)

Holmberg, K.; Bake, B.; Pipkorn, U.

1988-01-01

The nasal mucosal blood flow in patients with allergic rhinitis was determined at nasal allergen challenges with the 133 Xenon washout method. Determinations were made in 12 subjects before and 15 minutes after challenge with diluent and increasing doses of allergen. The time course was followed in eight subjects by means of repeated measurements during 1 hour after a single allergen dose. Finally, the blood flow was measured after unilateral allergen challenge in the contralateral nasal cavity. A dose-dependent decrease in blood flow was found after nasal challenge with increasing doses of allergens, whereas challenge with diluent alone did not induce any changes. The highest allergen dose, which also induced pronounced nasal symptoms, resulted in a decrease in blood flow of 25% (p less than 0.001). The time-course study demonstrated a maximum decrease in blood flow 10 to 20 minutes after challenge and then a gradual return to baseline. Unilateral allergen challenge resulted in a decrease in blood flow in the contralateral, unchallenged nasal cavity, suggesting that part of the allergen-induced changes in blood flow were reflex mediated

Effect of Intervention in Mast Cell Function Before Reperfusion on Renal Ischemia-Reperfusion Injury in Rats

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Fei Tong

2016-06-01

Full Text Available Background/Aims: Mast cells are sparsely distributed in the kidneys under normal conditions; however, the number of mast cells increases dramatically during renal ischemia/reperfusion injury (RI/RI. When mast cells are stimulated, numerous mediators are released, and under pathological conditions, they produce a wide range of biological effects. The aim of this study was to investigate the effect of intervention in mast cell function before reperfusion on RI/RI. Methods: Sprague-Dawley (SD rats (n=50 were randomized into five groups: sham group, ischemia/reperfusion (I/R group, cromolyn sodium treatment group (CS+I/R group, ketotifen treatment group (K+I/Rgroup, and compound 48/80 treatment group (C+I/R group. I/R injury was induced by bilateral renal artery and vein occlusion for 45 min followed by 24 h of reperfusion. The agents were intravenously administered 5 min before reperfusion through the tail vein. The serum levels of blood urea nitrogen(BUN, serum creatinine (Scr and histamine and the kidney levels of malondialdehyde (MDA, superoxide dismutase (SOD, tumor necrosis factor α (TNF-α and interleukin-6 (IL-6 were assessed. The expression of intracellular adhesion molecule-1 (ICAM-1 in renal tissue was also measured. Results: I/R injury resulted in severe renal injury, as demonstrated by a large increase in injury scores; serum levels of BUN, Scr and histamine; and kidney levels of MDA, TNF-α, and IL-6; this was accompanied by reduced SOD activity and upregulated ICAM-1 expression. Treatment with cromolyn sodium or ketotifen markedly alleviated I/R-mediated kidney injury, whereas compound 48/80 further aggravated kidney injury. Conclusion: Intervention in mast cell activity prior to reperfusionhas a strong effect on RI/RI.

Mammary blood flow regulation in the nursing rabbit

International Nuclear Information System (INIS)

Katz, M.; Creasy, R.K.

1984-01-01

Cardiac output and mammary blood flow distribution prior to and after suckling were studied in 10 nursing rabbits by means of radionuclide-labeled microspheres. Suckling was followed by a 5.8% rise in cardiac output and a 20.4% rise in mammary blood flow. Determinations of intraglandular blood flow distribution have shown that there was a 43% increase in blood flow to the glands suckled from as compared to a 22.7% rise to the contralateral untouched glands and a 4.9% rise in the remainder of untouched glands. The conclusion is that a local mechanism may be involved in the regulation of mammary blood flow in the nursing rabbit

The possible protective effects of dipyridamole on ischemic reperfusion injury of priapism

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Ersagun Karaguzel

2016-02-01

Full Text Available ABSTRACT Purpose To investigate the protective effects against ischemia reperfusion injury of dipyridamole in a model of induced priapism in rats. Materials and Methods Twenty-four male Sprague-Dawley rats were divided into four groups, control, P/R, P/R+DMSO and P/R+D. 3ml blood specimens were collected from vena cava inferior in order to determine serum MDA, IMA, TAS, TOS and OSI values, and penile tissue was taken for histopathological examination in control group. Priapism was induced in P/R group. After 1h, priapism was concluded and 30 min reperfusion was performed. In P/R+DMSO group 1ml/kg DMSO was administered intraperitoneally 30 min before reperfusion, while in P/R+D group 10mg/kg dipyridamole was administered intraperitoneally 30 min before reperfusion. Blood and penis specimens were collected after the end of 30 min reperfusion period. Sinusoidal area (µm2, tears in tunica albuginea and injury parameters in sinusoidal endothelium of penis were investigated. Results Histopathological examination revealed no significant changes in term of sinusoidal area. A decrease in tears was observed in P/R+D group compared to P/R group (p0.05. There were no significant differences in MDA and IMA values between groups. A significant increase in TOS and OSI values was observed in P/R+D group compared to P/R group. A significant decrease in TAS levels was observed in P/R+D group compared to the P/R group. Conclusions The administration of dipyridamole before reperfusion in ischemic priapism model has a potential protective effect against histopathological injury of the penis.

Accumulation of polymorphonuclear leukocytes in reperfused ischemic canine myocardium: relation with tissue viability assessed by fluorine-18-2-deoxyglucose uptake

International Nuclear Information System (INIS)

Wijns, W.; Melin, J.A.; Leners, N.

1988-01-01

Polymorphonuclear leukocytes may participate in reperfusion injury. Whether leukocytes affect viable or only irreversibly injured tissue is not known. Therefore, we assessed the accumulation of 111In-labeled leukocytes in tissue samples characterized as either ischemic but viable or necrotic by metabolic, histochemical, and ultrastructural criteria. Six open-chest dogs received left anterior descending coronary occlusion for 2 hr followed by 4 hr reperfusion. Myocardial blood flow was determined by microspheres and autologous 111In-labeled leukocytes were injected intravenously. Fluorine-18-2-deoxyglucose, a tracer of exogenous glucose utilization, was injected 3 hr after reperfusion. The dogs were killed 4 hr after reperfusion. The risk and the necrotic regions were assessed following in vivo dye injection and postmortem tetrazolium staining. Myocardial samples were obtained in the ischemic but viable, necrotic and normal zones, and counted for 111In and 18F activity. Compared to normal, leukocytes were entrapped in necrotic regions (111In activity: 207 +/- 73%) where glucose uptake was decreased (26 +/- 15%). A persistent glucose uptake, marker of viability, was mainly seen in risk region (135 +/- 85%) where leukocytes accumulation was moderate in comparison to normal zone (146 +/- 44%). Thus, the glucose uptake observed in viable tissue is mainly related to myocytes metabolism and not to leukocytes metabolism

Relation between reperfusion and hemorrhagic transformation in acute ischemic stroke

Energy Technology Data Exchange (ETDEWEB)

Horsch, Alexander D. [University Medical Center Utrecht, Department of Radiology, Utrecht (Netherlands); Rijnstate Hospital, Department of Radiology, Arnhem (Netherlands); Dankbaar, Jan Willem; Niesten, Joris M.; Seeters, Tom van; Schaaf, Irene C. van der; Velthuis, Birgitta K. [University Medical Center Utrecht, Department of Radiology, Utrecht (Netherlands); Graaf, Yolanda van der [Julius Center for Health Sciences and Primary Care, Utrecht (Netherlands); Kappelle, L.J. [University Medical Center, Department of Neurology, Utrecht Stroke Center, Utrecht (Netherlands); Collaboration: DUST investigators

2015-12-15

Intravenous recombinant tissue plasminogen activator (IV-rtPA) is given in acute ischemic stroke patients to achieve reperfusion. Hemorrhagic transformation (HT) is a serious complication of IV-rtPA treatment and related to blood-brain barrier (BBB) injury. It is unclear whether HT occurs secondary to reperfusion in combination with ischemic BBB injury or is caused by the negative effect of IV-rtPA on BBB integrity. The aim of this study was to establish the association between reperfusion and the occurrence of HT. From the DUST study, patients were selected with admission and follow-up non-contrast CT (NCCT) and CT perfusion (CTP) imaging, and a perfusion deficit in the middle cerebral artery territory on admission. Reperfusion was categorized qualitatively as reperfusion or no-reperfusion by visual comparison of admission and follow-up CTP. Occurrence of HT was assessed on follow-up NCCT. The association between reperfusion and occurrence of HT on follow-up was estimated by calculating odds ratios (ORs) and 95 % confidence intervals (CIs) with additional stratification for IV-rtPA treatment. Inclusion criteria were met in 299 patients. There was no significant association between reperfusion and HT (OR 1.2 95%CI 0.5-3.1). In patients treated with IV-rtPA (n = 203), the OR was 1.3 (95%CI 0.4-4.0), and in patients not treated with IV-rtPA (n = 96), the OR was 0.8 (95%CI 0.1-4.5). HT occurred in 14 % of the IV-rtPA patients and in 7 % of patients without IV-rtPA (95%CI of difference -1 to 14 %). Our results suggest that the increased risk of HT after acute ischemic stroke treatment is not dependent on the reperfusion status. (orig.)

Reperfusion promotes mitochondrial dysfunction following focal cerebral ischemia in rats.

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Jun Li

Full Text Available BACKGROUND AND PURPOSE: Mitochondrial dysfunction has been implicated in the cell death observed after cerebral ischemia, and several mechanisms for this dysfunction have been proposed. Reperfusion after transient cerebral ischemia may cause continued and even more severe damage to the brain. Many lines of evidence have shown that mitochondria suffer severe damage in response to ischemic injury. The purpose of this study was to observe the features of mitochondrial dysfunction in isolated mitochondria during the reperfusion period following focal cerebral ischemia. METHODS: Male Wistar rats were subjected to focal cerebral ischemia. Mitochondria were isolated using Percoll density gradient centrifugation. The isolated mitochondria were fixed for electron microscopic examination; calcium-induced mitochondrial swelling was quantified using spectrophotometry. Cyclophilin D was detected by Western blotting. Fluorescent probes were used to selectively stain mitochondria to measure their membrane potential and to measure reactive oxidative species production using flow cytometric analysis. RESULTS: Signs of damage were observed in the mitochondrial morphology after exposure to reperfusion. The mitochondrial swelling induced by Ca(2+ increased gradually with the increasing calcium concentration, and this tendency was exacerbated as the reperfusion time was extended. Cyclophilin D protein expression peaked after 24 hours of reperfusion. The mitochondrial membrane potential was decreased significantly during the reperfusion period, with the greatest decrease observed after 24 hours of reperfusion. The surge in mitochondrial reactive oxidative species occurred after 2 hours of reperfusion and was maintained at a high level during the reperfusion period. CONCLUSIONS: Reperfusion following focal cerebral ischemia induced significant mitochondrial morphological damage and Ca(2+-induced mitochondrial swelling. The mechanism of this swelling may be mediated by

Postradiation regional cerebral blood flow in primates

International Nuclear Information System (INIS)

Cockerham, L.G.; Cerveny, T.J.; Hampton, J.D.

1986-01-01

Early transient incapacitation (ETI) is the complete cessation of performance during the first 30 min after radiation exposure and performance decrement (PD) is a reduction in performance at the same time. Supralethal doses of radiation have been shown to produce a marked decrease in regional cerebral blood flow in primates concurrent with hypotension and a dramatic release of mast cell histamine. In an attempt to elucidate mechanisms underlying the radiation-induced ETI/PD phenomenon and the postradiation decrease in cerebral blood flow, primates were exposed to 100 Gy (1 Gy = 100 rads), whole-body, gamma radiation. Pontine and cortical blood flows were measured by hydrogen clearance, before and after radiation exposure. Systemic blood pressures were determined simultaneously. Systemic arterial histamine levels were determined preradiation and postradiation. Data obtained indicated that radiated animals showed a decrease in blood flow of 63% in the motor cortex and 51% in the pons by 10 min postradiation. Regional cerebral blood flow of radiated animals showed a slight recovery 20 min postradiation, followed by a fall to the 10 min nadir by 60 min postradiation. Immediately, postradiation systemic blood pressure fell 67% and remained at that level for the remainder of the experiment. Histamine levels in the radiated animals increased a hundredfold 2 min postradiation. This study indicates that regional cerebral blood flow decreases postradiation with the development of hypotension and may be associated temporally with the postradiation release of histamine

Regional cerebral blood flow in schizophrenic patients

International Nuclear Information System (INIS)

Sagawa, Katsuo; Sibuya, Isoo; Oiji, Arata; Kawakatsu, Sinobu; Morinobu, Shigeru; Totsuka, Shiro; Kinoshita, Osami; Yazaki, Mitsuyasu.

1990-01-01

Seventy-six schizophrenic patients were examined by a Xe-133 inhalation method to determine regional cerebral blood flow. A decreased blood flow was observed in the frontal lobe, especially in the right inferior part. In a study on the relationship between disease subtypes and regional cerebral blood flow, negative symptoms were found more predominantly associated with dissolution type than delusion type. In the group of dissolution type, a decreased blood flow was observed in both the right inferior frontal lobe and the right upper hemisphere, in comparison to the group of delution type. Patients presenting with auditory hallucination had a significantly higher incidence of both negative and positive symptoms, as compared with those not presenting with it. In such patients, a significantly decreased blood flow was also seen in the left upper frontal lobe and the bilateral parietal lobe. Xe-133 inhalation method should assist in evaluating brain function in schizophrenic patients, thus leading to the likelihood of developing a new treatment modality. (N.K.)

Data adaptive estimation of transversal blood flow velocities

DEFF Research Database (Denmark)

Pirnia, E.; Jakobsson, A.; Gudmundson, E.

2014-01-01

the transversal blood flow. In this paper, we propose a novel data-adaptive blood flow estimator exploiting this modulation scheme. Using realistic Field II simulations, the proposed estimator is shown to achieve a notable performance improvement as compared to current state-of-the-art techniques.......The examination of blood flow inside the body may yield important information about vascular anomalies, such as possible indications of, for example, stenosis. Current Medical ultrasound systems suffer from only allowing for measuring the blood flow velocity along the direction of irradiation......, posing natural difficulties due to the complex behaviour of blood flow, and due to the natural orientation of most blood vessels. Recently, a transversal modulation scheme was introduced to induce also an oscillation along the transversal direction, thereby allowing for the measurement of also...

Blood flow in healed and inflamed periodontal tissues of dogs

International Nuclear Information System (INIS)

Hock, J.M.; Kim, S.

1987-01-01

The objectives of this study were to determine if increased blood flow associated with gingivitis would decrease following resolution of gingival inflammation in dogs with periodontitis; if increased blood flow in inflamed gingiva was associated with changes in the blood flow of alveolar bone, and if blood flow in gingiva and alveolar bone increased if periodontitis was reactivated by ligating teeth. Regional blood flow was measured in dogs with pre-existing periodontitis, using radioisotope-labelled, plastic microspheres. In the first experiment on 4 adult Beagle dogs, teeth in the left jaws were treated to resolve the periodontitis, while teeth in the right jaws were not treated. Gingival and bone blood flow were measured after 12 wk. Blood flow was significantly (p 1 and gingiva with G.I.<2 was significant (p<0.04). Blood flow in bone was not altered by changes in the inflammatory status of the overlying gingiva. The findings suggest that changes in blood flow associated with inflammation are reversible and that blood flow alveolar bone is regulated independently of gingival blood flow. (author)

Hemorheological changes in ischemia-reperfusion: an overview on our experimental surgical data.

Science.gov (United States)

Nemeth, Norbert; Furka, Istvan; Miko, Iren

2014-01-01

Blood vessel occlusions of various origin, depending on the duration and extension, result in tissue damage, causing ischemic or ischemia-reperfusion injuries. Necessary surgical clamping of vessels in vascular-, gastrointestinal or parenchymal organ surgery, flap preparation-transplantation in reconstructive surgery, as well as traumatological vascular occlusions, all present special aspects. Ischemia and reperfusion have effects on hemorheological state by numerous ways: besides the local metabolic and micro-environmental changes, by hemodynamic alterations, free-radical and inflammatory pathways, acute phase reactions and coagulation changes. These processes may be harmful for red blood cells, impairing their deformability and influencing their aggregation behavior. However, there are still many unsolved or non-completely answered questions on relation of hemorheology and ischemia-reperfusion. How do various organ (liver, kidney, small intestine) or limb ischemic-reperfusionic processes of different duration and temperature affect the hemorheological factors? What is the expected magnitude and dynamics of these alterations? Where is the border of irreversibility? How can hemorheological investigations be applied to experimental models using laboratory animals in respect of inter-species differences? This paper gives a summary on some of our research data on organ/tissue ischemia-reperfusion, hemorheology and microcirculation, related to surgical research and experimental microsurgery.

Regulation of pulpal blood flow

International Nuclear Information System (INIS)

Kim, S.

1985-01-01

The regulation of blood flow of the dental pulp was investigated in dogs and rats anesthetized with sodium pentobarbital. Pulpal blood flow was altered by variations of local and systemic hemodynamics. Macrocirculatory blood flow (ml/min/100 g) in the dental pulp was measured with both the 133 Xe washout and the 15-microns radioisotope-labeled microsphere injection methods on the canine teeth of dogs, to provide a comparison of the two methods in the same tooth. Microcirculatory studies were conducted in the rat incisor tooth with microscopic determination of the vascular pattern, RBC velocity, and intravascular volumetric flow distribution. Pulpal resistance vessels have alpha- and beta-adrenergic receptors. Activation of alpha-receptors by intra-arterial injection of norepinephrine (NE) caused both a reduction in macrocirculatory Qp in dogs and decreases in arteriolar and venular diameters and intravascular volumetric flow (Qi) in rats. These responses were blocked by the alpha-antagonist PBZ. Activation of beta-receptors by intra-arterial injection of isoproterenal (ISO) caused a paradoxical reduction of Qp in dogs. In rats, ISO caused a transient increase in arteriolar Qi followed by a flow reduction; arteriolar dilation was accompanied by venular constriction. These macrocirculatory and microcirculatory responses to ISO were blocked by the alpha-antagonist propranolol

Prediction of blood pressure and blood flow in stenosed renal arteries using CFD

Science.gov (United States)

Jhunjhunwala, Pooja; Padole, P. M.; Thombre, S. B.; Sane, Atul

2018-04-01

In the present work an attempt is made to develop a diagnostive tool for renal artery stenosis (RAS) which is inexpensive and in-vitro. To analyse the effects of increase in the degree of severity of stenosis on hypertension and blood flow, haemodynamic parameters are studied by performing numerical simulations. A total of 16 stenosed models with varying degree of stenosis severity from 0-97.11% are assessed numerically. Blood is modelled as a shear-thinning, non-Newtonian fluid using the Carreau model. Computational Fluid Dynamics (CFD) analysis is carried out to compute the values of flow parameters like maximum velocity and maximum pressure attained by blood due to stenosis under pulsatile flow. These values are further used to compute the increase in blood pressure and decrease in available blood flow to kidney. The computed available blood flow and secondary hypertension for varying extent of stenosis are mapped by curve fitting technique using MATLAB and a mathematical model is developed. Based on these mathematical models, a quantification tool is developed for tentative prediction of probable availability of blood flow to the kidney and severity of stenosis if secondary hypertension is known.

Assessment of hand blood flow: a modified technique

International Nuclear Information System (INIS)

Kirsh, J.C.; Tepperman, P.S.

1985-01-01

A blood flow artifact has been identified with the conventional bolus-injection technique in radionuclide studies of hand disorders. The artifact, consisting of increased blood flow on the injected side, was demonstrated in 22 of 25 subjects. Using a modified injection technique to allow time for local blood flow to return to the basal state, the artifact could be eliminated in 19 of 23 additional subjects. Use of this simple protocol should help avoid misinterpretation of blood flow asymmetry in the assessment of hand disorders

Bone blood flow after spinal paralysis in the rat

International Nuclear Information System (INIS)

Takahashi, H.; Yamamuro, T.; Okumura, H.; Kasai, R.; Tada, K.

1990-01-01

The goal of this study was to investigate the acute and chronic effects of paralysis induced by spinal cord section or sciatic neurotomy on bone blood flow in the rat. Regional bone blood flow was measured in the early stage with the hydrogen washout technique and the change of whole bone blood flow was measured in the early and the late stages with the radioactive microsphere technique. Four to 6 h after cordotomy at the level of the 13th thoracic vertebra, the regional bone blood flow in the denervated tibia increased significantly (p less than 0.01). After hemicordotomy with rhizotomy at the same level, the regional bone blood flow in the denervated tibia increased significantly (p less than 0.05) 6 h postoperatively. The whole bone blood flow in the denervated tibia had also increased significantly (p less than 0.05) at 6 h and at 4 and 12 weeks postoperatively. After sciatic neurotomy, the regional and the whole bone blood flow in the paralytic tibia did not change significantly. The present study demonstrated that monoplegic paralysis caused an increase in bone blood flow in the denervated hind limb from a very early stage. It was suggested that the spinal nervous system contributed to the control of bone blood flow

Measurement of bone blood flow in sheep

International Nuclear Information System (INIS)

Rosenthal, M.S.; Lehner, C.E.; Pearson, D.W.; Kanikula, T.; Adler, G.; Venci, R.; Lanphier, E.H.; DeLuca, P.M. Jr.

1984-01-01

Bone blood flow in sheep tibia has been estimated via the measurement of the perfusion limited clearance of 41 Ar from the bone mineral matrix following fast neutron activation of 44 Ca. Tibia blood flows were estimated for the intact sheep, and after the installation of an intramedullary pressure tap to elevate bone marrow pressure by saline infusion. The results indicate that normal blood flow in the tibia is in the range of 1.1 to 3.7 ml/100ml-min in the intact animal and at normal marrow pressure. With an elevated intramedullary pressure of approximately 100 mmHg, the bone blood flow measured varied around 0.5 to 1.1 ml/100ml-min. 12 refs., 5 figs., 1 tab

Self-separation of blood plasma from whole blood during the capillary flow in microchannel

Science.gov (United States)

Nunna, Bharath Babu; Zhuang, Shiqiang; Lee, Eon Soo

2017-11-01

Self-separation of blood plasma from whole blood in microchannels is of great importance due to the enormous range of applications in healthcare and diagnostics. Blood is a multiphase complex fluid, composed of cells suspended in blood plasma. RBCs are the suspended particles whose shape changes during the flow of blood. The primary constituents of blood are erythrocytes or red blood cells (RBCs), leukocytes or white blood cells (WBCs), thrombocytes or platelets and blood plasma. The existence of RBCs in blood makes the blood a non-Newtonian fluid. The current study of separation of blood plasma from whole blood during self-driven flows in a single microchannel without bifurcation, by enhancing the capillary effects. The change in the capillary effect results in a change in contact angle which directly influences the capillary flow. The flow velocity directly influences the net force acting on the RBCs and influence the separation process. The experiments are performed on the PDMS microchannels with different contact angles by altering the surface characteristics using plasma treatment. The change in the separation length is studied during the capillary flow of blood in microchannel. Bharath Babu Nunna is a researcher in mechanical engineering and implementing the novel and innovative technologies in the biomedical devices to enhance the sensitivity of the disease diagnosis.

Modeling microcirculatory blood flow: current state and future perspectives.

Science.gov (United States)

Gompper, Gerhard; Fedosov, Dmitry A

2016-01-01

Microvascular blood flow determines a number of important physiological processes of an organism in health and disease. Therefore, a detailed understanding of microvascular blood flow would significantly advance biophysical and biomedical research and its applications. Current developments in modeling of microcirculatory blood flow already allow to go beyond available experimental measurements and have a large potential to elucidate blood flow behavior in normal and diseased microvascular networks. There exist detailed models of blood flow on a single cell level as well as simplified models of the flow through microcirculatory networks, which are reviewed and discussed here. The combination of these models provides promising prospects for better understanding of blood flow behavior and transport properties locally as well as globally within large microvascular networks. © 2015 Wiley Periodicals, Inc.

Blood flow in healed and inflamed periodontal tissues of dogs

Energy Technology Data Exchange (ETDEWEB)

Hock, J.M.; Kim, S.

1987-01-01

The objectives of this study were to determine if increased blood flow associated with gingivitis would decrease following resolution of gingival inflammation in dogs with periodontitis; if increased blood flow in inflamed gingiva was associated with changes in the blood flow of alveolar bone, and if blood flow in gingiva and alveolar bone increased if periodontitis was reactivated by ligating teeth. Regional blood flow was measured in dogs with pre-existing periodontitis, using radioisotope-labelled, plastic microspheres. In the first experiment on 4 adult Beagle dogs, teeth in the left jaws were treated to resolve the periodontitis, while teeth in the right jaws were not treated. Gingival and bone blood flow were measured after 12 wk. Blood flow was significantly (p<0.05) lower in non-inflamed healed gingiva (32.1 +- 2.7 ml/min/100 g) than in inflamed gingiva (46.1 +- 5.3 ml/min/100 g). No differences in the blood flow of the alveolar bone underlying inflamed or non-inflamed gingiva were present. In the second experiment, the right mandibular teeth of 5 dogs were treated to resolve periodontitis while teeth in the other quadrants were ligated for 4, 10 or 12 wk. The duration of ligation did not alter blood flow. Gingival blood flow around ligated maxillary and mandibular teeth was comparable and approximately 54% higher than around non-ligated teeth (p<0.03). The difference in blood flow between gingiva with G.I.>1 and gingiva with G.I.<2 was significant (p<0.04). Blood flow in bone was not altered by changes in the inflammatory status of the overlying gingiva. The findings suggest that changes in blood flow associated with inflammation are reversible and that blood flow alveolar bone is regulated independently of gingival blood flow.

Myocardial hypoperfusion/reperfusion tolerance with exercise training in hypertension.

Science.gov (United States)

Reger, Patricia O; Barbe, Mary F; Amin, Mamta; Renna, Brian F; Hewston, Leigh Ann; MacDonnell, Scott M; Houser, Steven R; Libonati, Joseph R

2006-02-01

The purpose of this study was to examine whether exercise training, superimposed on compensated-concentric hypertrophy, could increase myocardial hypoperfusion-reperfusion (H/R) tolerance. Female Wistar-Kyoto rats (WKY) and spontaneously hypertensive rats (SHR) (age: 4 mo; N = 40) were placed into a sedentary (SED) or exercise training (TRD) group (treadmill running; 25 m/min, 1 h/day, 5 days/wk for 16 wk). Four groups were studied: WKY-SED (n = 10), WKY-TRD (n = 10), SHR-SED (n = 10), and SHR-TRD (n = 10). Blood pressure and heart rate were determined, and in vitro isolated heart performance was measured with a retrogradely perfused, Langendorff isovolumic preparation. The H/R protocol consisted of a 75% reduction in coronary flow for 17 min followed by 30 min of reperfusion. Although the rate-pressure product was significantly elevated in SHR relative to WKY, training-induced bradycardia reduced the rate-pressure product in SHR-TRD (P Endurance training superimposed on hypertension-induced compensated hypertrophy conferred no further cardioprotection to H/R. Postreperfusion 72-kDa heat shock protein abundance was enhanced in WKY-TRD and both groups of SHR relative to WKY-SED (P hypertension and endurance training individually improved H/R and that increased postreperfusion 72-kDa heat shock protein abundance was, in part, associated with the cardioprotective phenotype observed in this study.

Investigation of intrarenal blood flow and urine flow aspects by scintillation camera

International Nuclear Information System (INIS)

Kawamura, J.; Hosokawa, S.; Yoshida, O.; Ishii, Y.; Torizuka, K.

1977-01-01

In order to clarify intrarenal dynamic processes related to regional distribution in patients with unilateral renal disease, two radioactive tracers, 133 Xe and /sup 99m/Tc-diethylenetriaminepentaacetic acid (/sup 99m/Tc-DTPA) were introduced into a renal artery and intrarenal blood flow and urine flow aspects were observed by scintillation camera. Cortical blood flow decreased and medullary blood flow relatively increased with the advance of renal damage. Urine flow curve from normal cortex showed two phasic patterns. One early phase might correspond to the appearance of the tracer through the proximal tubule and a second phase might correspond to the appearance of the tracer through the loop of Henle to the distal tubule. Under mannitol diuresis, two phasic urine flow curves from the cortex became obscured and the peak time of pelvic curve shifted to the earlier period. These studies were considered to be useful in evaluating unilateral renal function and might offer a good insight for intrarenal physiology concerning blood flow as well as urine flow

Thymoquinone protects end organs from abdominal aorta ischemia/reperfusion injury in a rat model

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Mehmet Salih Aydin

2015-02-01

Full Text Available Introduction: Previous studies have demonstrated that thymoquinone has protective effects against ischemia reperfusion injury to various organs like lungs, kidneys and liver in different experimental models. Objective: We aimed to determine whether thymoquinone has favorable effects on lung, renal, heart tissues and oxidative stress in abdominal aorta ischemia-reperfusion injury. Methods: Thirty rats were divided into three groups as sham (n=10, control (n=10 and thymoquinone (TQ treatment group (n=10. Control and TQ-treatment groups underwent abdominal aorta ischemia for 45 minutes followed by a 120-min period of reperfusion. In the TQ-treatment group, thymoquinone was given 5 minutes. before reperfusion at a dose of 20 mg/kg via an intraperitoneal route. Total antioxidant capacity, total oxidative status (TOS, and oxidative stress index (OSI in blood serum were measured and lung, kidney, and heart tissue histopathology were evaluated with light microscopy. Results: Total oxidative status and oxidative stress index activity in blood samples were statistically higher in the control group compared to the sham and TQ-treatment groups (P<0.001 for TOS and OSI. Control group injury scores were statistically higher compared to sham and TQ-treatment groups (P<0.001 for all comparisons. Conclusion: Thymoquinone administered intraperitoneally was effective in reducing oxidative stress and histopathologic injury in an acute abdominal aorta ischemia-reperfusion rat model.

Quantitative myocardial blood flow with Rubidium-82 PET

DEFF Research Database (Denmark)

Hagemann, Christoffer E; Ghotbi, Adam A; Kjær, Andreas

2015-01-01

Positron emission tomography (PET) allows assessment of myocardial blood flow in absolute terms (ml/min/g). Quantification of myocardial blood flow (MBF) and myocardial flow reserve (MFR) extend the scope of conventional semi-quantitative myocardial perfusion imaging (MPI): e.g. in 1) identificat......Positron emission tomography (PET) allows assessment of myocardial blood flow in absolute terms (ml/min/g). Quantification of myocardial blood flow (MBF) and myocardial flow reserve (MFR) extend the scope of conventional semi-quantitative myocardial perfusion imaging (MPI): e.g. in 1...... global MFR and major adverse cardiovascular events (MACE), and together with new diagnostic possibilities from measuring the longitudinal myocardial perfusion gradient, cardiac (82)Rb PET faces a promising clinical future. This article reviews current evidence on quantitative (82)Rb PET's ability...

Extract of grapefruit-seed reduces acute pancreatitis induced by ischemia/reperfusion in rats: possible implication of tissue antioxidants.

Science.gov (United States)

Dembinski, A; Warzecha, Z; Konturek, S J; Ceranowicz, P; Dembinski, M; Pawlik, W W; Kusnierz-Cabala, B; Naskalski, J W

2004-12-01

Grapefruit seed extract (GSE) has been shown to exert antibacterial, antifungal and antioxidant activity possibly due to the presence of naringenin, the flavonoid with cytoprotective action on the gastric mucosa. No study so far has been undertaken to determine whether this GSE is also capable of preventing acute pancreatic damage induced by ischemia/reperfusion (I/R), which is known to result from reduction of anti-oxidative capability of pancreatic tissue, and whether its possible preventive effect involves an antioxidative action of this biocomponent. In this study carried out on rats with acute hemorrhagic pancreatitis induced by 30 min partial pancreatic ischemia followed by 6 h of reperfusion, the GSE or vehicle (vegetable glycerin) was applied intragastrically in gradually increasing amounts (50-500 microl) 30 min before I/R. Pretreatment with GSE decreased the extent of pancreatitis with maximal protective effect of GSE at the dose 250 microl. GSE reduced the pancreatitis-evoked increase in serum lipase and poly-C specific ribonuclease activity, and attenuated the marked fall in pancreatic blood flow and pancreatic DNA synthesis. GSE administered alone increased significantly pancreatic tissue content of lipid peroxidation products, malondialdehyde and 4-hydroxyalkens, and when administered before I/R, GSE reduced the pancreatitis-induced lipid peroxidation. We conclude that GSE exerts protective activity against I/R-induced pancreatitis probably due to the activation of antioxidative mechanisms in the pancreas and the improvement of pancreatic blood flow.

Spiral blood flow in aorta-renal bifurcation models.

Science.gov (United States)

Javadzadegan, Ashkan; Simmons, Anne; Barber, Tracie

2016-01-01

The presence of a spiral arterial blood flow pattern in humans has been widely accepted. It is believed that this spiral component of the blood flow alters arterial haemodynamics in both positive and negative ways. The purpose of this study was to determine the effect of spiral flow on haemodynamic changes in aorta-renal bifurcations. In this regard, a computational fluid dynamics analysis of pulsatile blood flow was performed in two idealised models of aorta-renal bifurcations with and without flow diverter. The results show that the spirality effect causes a substantial variation in blood velocity distribution, while causing only slight changes in fluid shear stress patterns. The dominant observed effect of spiral flow is on turbulent kinetic energy and flow recirculation zones. As spiral flow intensity increases, the rate of turbulent kinetic energy production decreases, reducing the region of potential damage to red blood cells and endothelial cells. Furthermore, the recirculation zones which form on the cranial sides of the aorta and renal artery shrink in size in the presence of spirality effect; this may lower the rate of atherosclerosis development and progression in the aorta-renal bifurcation. These results indicate that the spiral nature of blood flow has atheroprotective effects in renal arteries and should be taken into consideration in analyses of the aorta and renal arteries.

Quantitative assessment of limb blood flow using Tc-99m labeled red blood cells

International Nuclear Information System (INIS)

Itoh, Kazuo; Shougase, Takashi; Kawamura, Naoyuki; Tsukamoto, Eriko; Nakada, Kunihiro; Sakuma, Makoto; Furudate, Masayori

1987-01-01

A quantitative assessment of limb blood flow using a non-diffusible radioindicator, Tc-99m labeled red blood cells, was reported. This was an application of venous occlusion plethysmography using radionuclide which was originally proposed by M. Fukuoka et al. The peripheral blood flow (mean ± s.e.) of 30 legs in a normal control group was 1.87 ± 0.08 ml/100 ml/min. In heart diseases (46 legs), it was 1.49 ± 0.13 ml/100 ml/min. The limb blood flow between a control group and heart diseases was statistically significant (p < 0.01) in the t-test. The peripheral blood flow at rest between diseased legs and normal legs in occlusive arterial disorders was also statistically significant (p < 0.01) in a paired t-test. RAVOP was done after the completion of objective studies such as radionuclide angiography or ventriculography. Technique and calculation of a blood flow were very easy and simple. RAVOP study which was originally proposed by Fukuoka et al. was reappraised to be hopeful for quantitative measurement of limb blood flow as a non-invasive technique using Tc-99m labeled red blood cells. (author)

Edaravone enhances the viability of ischemia/reperfusion flaps.

Science.gov (United States)

Zhang, Dong-Yi; Kang, Shen-Song; Zhang, Zheng-Wen; Wu, Rui

2017-02-01

The purpose of the experiment was to study the efficacy of edaravone in enhancing flap viability after ischemia/reperfusion (IR) and its mechanism. Forty-eight adult male SD rats were randomly divided into 3 groups: control group (n=16), IR group (n=16), and edaravone-treated IR group (n=16). An island flap at left lower abdomen (6.0 cm×3.0 cm in size), fed by the superficial epigastric artery and vein, was created in each rat of all the three groups. The arterial blood flow of flaps in IR group and edaravone-treated IR group was blocked for 10 h, and then the blood perfusion was restored. From 15 min before reperfusion, rats in the edaravone-treated IR group were intraperitoneally injected with edaravone (10 mg/kg), once every 12 h, for 3 days. Rats in the IR group and control group were intraperitoneally injected with saline, with the same method and frequency as the rats in the edaravone-treated IR group. In IR group and edaravone-treated IR group, samples of flaps were harvested after reperfusion of the flaps for 24 h. In the control group, samples of flaps were harvested 34 h after creation of the flaps. The content of malondialdehyde (MDA) and activity of superoxide dismutase (SOD) were determined, and changes in organizational structure and infiltration of inflammatory cells were observed by hematoxylin-eosin (HE) staining, apoptotic cells of vascular wall were marked by terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) assay, and the apoptotic rate of cells in vascular wall was calculated. The ultrastructural changes of vascular endothelial cells were observed by transmission electron microscopy (TEM). Seven days after the operation, we calculated the flap viability of each group, and marked vessels of flaps by immunohistochemical staining for calculating the average number of subcutaneous vessels. The results showed that the content of MDA, the number of multicore inflammatory cells and apoptotic rate of cells in vascular wall

Increased bone marrow blood flow in polycythemia vera

International Nuclear Information System (INIS)

Lathinen, R.; Lathinen, T.; Hyoedynmaa, S.

1983-01-01

Bone marrow blood flow was measured in polycythemia vera, in compensatory and in relative polycythemia with a 133 Xe washout method. In the treated polycythemia vera bone marrow blood flow was significantly increased compared with the age-matched controls. The fraction of blood flow entering the bone and flowing through the hematopoietic marrow was markedly increased in both the untreated and the treated polycythemia vera. Although the number of observations in compensatory and relative polycythemia was small, the results suggest that bone marrow blood flow is not markedly increased in these diseases. The results also suggest that in older patients the simple 133 Xe method may support the diagnosis of polycythemia vera. (orig.)

Increased bone marrow blood flow in polycythemia vera

Energy Technology Data Exchange (ETDEWEB)

Lathinen, R.; Lathinen, T.; Hyoedynmaa, S.

1983-01-01

Bone marrow blood flow was measured in polycythemia vera, in compensatory and in relative polycythemia with a /sup 133/Xe washout method. In the treated polycythemia vera bone marrow blood flow was significantly increased compared with the age-matched controls. The fraction of blood flow entering the bone and flowing through the hematopoietic marrow was markedly increased in both the untreated and the treated polycythemia vera. Although the number of observations in compensatory and relative polycythemia was small, the results suggest that bone marrow blood flow is not markedly increased in these diseases. The results also suggest that in older patients the simple /sup 133/Xe method may support the diagnosis of polycythemia vera.

Flow heterogeneity following global no-flow ischemia in isolated rabbit heart

International Nuclear Information System (INIS)

Marshall, Robert C.; Powers-Risius, Patricia; Reutter, Bryan W.; Schustz, Amy M.; Kuo, Chaincy; Huesman, Michelle K.; Huesman, Ronald H.

2002-01-01

The purpose of this study was to evaluate flow heterogeneity and impaired reflow during reperfusion following 60 min global no-flow ischemia in the isolated rabbit heart. Radiolabeled microspheres were used to measure relative flow in small left ventricular (LV) segments in five ischemia + reperfused hearts and in five non-ischemic controls. Although variable in the post-ischemic hearts, flow heterogeneity was increased relative to pre-ischemia for the whole LV (0.92 plus or minus 0.41 vs. 0.37 plus or minus 0.07, P < 0.05) as well as the subendocardium (Endo) and subepicardium (Epi) considered separately (endo: 1.28 plus or minus 0.74 vs. 0.30 plus or minus 0.09; epi: 0.69 plus or minus 0.22 vs. 0.38 plus or minus 0.08; P < 0.05 for both comparisons) during early reperfusion. There were also segments with abnormally reduced reflow. The number of segments with abnormally reduced reflow increased as flow heterogeneity increased. Abnormally reduced reflow indicates that regional ischemia can persist despite restoration of normal global flow. In addition, the relationship between regional and global flow is altered and venous outflow is derived from regions with continued perfusion and not the whole LV. These observations emphasize the need to quantify regional reflow during reperfusion following sustained no-flow ischemia in the isolated rabbit heart

Flow heterogeneity following global no-flow ischemia in isolated rabbit heart

Energy Technology Data Exchange (ETDEWEB)

Marshall, Robert C.; Powers-Risius, Patricia; Reutter, Bryan W.; Schustz, Amy M.; Kuo, Chaincy; Huesman, Michelle K.; Huesman, Ronald H.

2003-02-01

The purpose of this study was to evaluate flow heterogeneity and impaired reflow during reperfusion following 60 min global no-flow ischemia in the isolated rabbit heart. Radiolabeled microspheres were used to measure relative flow in small left ventricular (LV) segments in five ischemia + reperfused hearts and in five non-ischemic controls. Although variable in the post-ischemic hearts, flow heterogeneity was increased relative to pre-ischemia for the whole LV (0.92 plus or minus 0.41 vs. 0.37 plus or minus 0.07, P < 0.05) as well as the subendocardium (Endo) and subepicardium (Epi) considered separately (endo: 1.28 plus or minus 0.74 vs. 0.30 plus or minus 0.09; epi: 0.69 plus or minus 0.22 vs. 0.38 plus or minus 0.08; P < 0.05 for both comparisons) during early reperfusion. There were also segments with abnormally reduced reflow. The number of segments with abnormally reduced reflow increased as flow heterogeneity increased. Abnormally reduced reflow indicates that regional ischemia can persist despite restoration of normal global flow. In addition, the relationship between regional and global flow is altered and venous outflow is derived from regions with continued perfusion and not the whole LV. These observations emphasize the need to quantify regional reflow during reperfusion following sustained no-flow ischemia in the isolated rabbit heart.

Cerebellar blood flow in methylmercury poisoning (Minamata disease)

Energy Technology Data Exchange (ETDEWEB)

Itoh, K.; Korogi, Y.; Tomiguchi, S.; Takahashi, M. [Dept. of Radiology, Kumamoto University School of Medicine (Japan); Okajima, T. [Dept. of Neurology, Johnan Hospital, Maihara, Johnan-mochi (Japan); Sato, H. [Dept. of Neurology, Minamata City General Hospital and Medical Centre (Japan)

2001-04-01

We looked at regional cerebellar blood flow in patients with Minamata disease (MD) using technetium-99 m ethyl cysteinate dimer (99m-Tc-ECD). We carried out single-photon emission computed tomography (SPECT) on 15 patients with MD (eight men, seven women, aged 51-78 years, mean 70.5 years) and 11 control subjects (eight men, three women, aged 62-80 years, mean 72.5 years). Regional blood flow was measured in the superior, middle, and inferior portions of the cerebellar hemispheres, and the frontal, temporal and occipital cerebral lobes. The degree of cerebellar atrophy was assessed on MRI. There were significant differences in regional blood flow in all parts of the cerebellum between patients and control, but no significant decrease was observed in the cerebrum. Blood flow was lower in the inferior cerebellum than in the other parts. Even in patients without cerebellar atrophy, flow was significantly decreased regional blood flow in the inferior part. (orig.)

Cerebellar blood flow in methylmercury poisoning (Minamata disease)

International Nuclear Information System (INIS)

Itoh, K.; Korogi, Y.; Tomiguchi, S.; Takahashi, M.; Okajima, T.; Sato, H.

2001-01-01

We looked at regional cerebellar blood flow in patients with Minamata disease (MD) using technetium-99 m ethyl cysteinate dimer (99m-Tc-ECD). We carried out single-photon emission computed tomography (SPECT) on 15 patients with MD (eight men, seven women, aged 51-78 years, mean 70.5 years) and 11 control subjects (eight men, three women, aged 62-80 years, mean 72.5 years). Regional blood flow was measured in the superior, middle, and inferior portions of the cerebellar hemispheres, and the frontal, temporal and occipital cerebral lobes. The degree of cerebellar atrophy was assessed on MRI. There were significant differences in regional blood flow in all parts of the cerebellum between patients and control, but no significant decrease was observed in the cerebrum. Blood flow was lower in the inferior cerebellum than in the other parts. Even in patients without cerebellar atrophy, flow was significantly decreased regional blood flow in the inferior part. (orig.)

Rat muscle blood flows during high-speed locomotion

International Nuclear Information System (INIS)

Armstrong, R.B.; Laughlin, M.H.

1985-01-01

We previously studied blood flow distribution within and among rat muscles as a function of speed from walking (15 m/min) through galloping (75 m/min) on a motor-driven treadmill. The results showed that muscle blood flows continued to increase as a function of speed through 75 m/min. The purpose of the present study was to have rats run up to maximal treadmill speeds to determine if blood flows in the muscles reach a plateau as a function of running speed over the animals normal range of locomotory speeds. Muscle blood flows were measured with radiolabeled microspheres at 1 min of running at 75, 90, and 105 m/min in male Sprague-Dawley rats. The data indicate that even at these relatively high treadmill speeds there was still no clear evidence of a plateau in blood flow in most of the hindlimb muscles. Flows in most muscles continued to increase as a function of speed. These observed patterns of blood flow vs. running speed may have resulted from the rigorous selection of rats that were capable of performing the high-intensity exercise and thus only be representative of a highly specific population of animals. On the other hand, the data could be interpreted to indicate that the cardiovascular potential during exercise is considerably higher in laboratory rats than has normally been assumed and that inadequate blood flow delivery to the muscles does not serve as a major limitation to their locomotory performance

Study on pretreatment of FPS-1 in rats with hepatic ischemia-reperfusion injury.

Science.gov (United States)

Lin, Shiqing; Liu, Kexuan; Wu, Weikang; Chen, Chao; Wang, Zhi; Zhang, Xuanhong

2009-01-01

This study was designed to determine whether FPS-1, the water-soluble polysaccharide isolated from fuzi, protected against hepatic damage in hepatic ischemia-reperfusion injury in rats, and its mechanism. SD rats were subjected to 60 min of hepatic ischemia, followed by 120 min reperfusion. FPS-1 (160 mg/kg/day) was administered orally for 5 days before ischemia-reperfusion injury in treatment group. Serum aspartate aminotransferase (AST), alanine aminotransferase (ALT) and albumin (ALB) were assayed to evaluate liver functions. Liver samples were taken for histological examination and determination of malondialdehyde (MDA), superoxide dismutase (SOD), that catalase (CAT) in liver. Na(+)-K(+)-ATPase and Ca(2+)-ATPase in mitochondria were measured with colorimetry method. Morphological changes were also investigated by using both light microscopy and electron microscopy (EM). In addition, apoptosis and oncosis were detected by Annexin V-FITC/PI immunofluorescent flow cytometry analysis. Serum AST and ALT levels were elevated in groups exposed to ischemia-reperfusion (p FPS-1 reversed all these biochemical parameters as well as histological alterations, evidently by increased SOD, CAT, reduced MDA and histological scores compared to the model group (p FPS-1 could attenuate the necrotic states by the detection of immunofluorescent flow cytometry analysis. Pretreatment with FPS-1 reduced hepatic ischemia-reperfusion injury through its potent antioxidative effects and attenuation of necrotic states.

Effect of black tea consumption on brachial artery flow-mediated dilation and ischaemia-reperfusion in humans.

Science.gov (United States)

Schreuder, Tim H A; Eijsvogels, Thijs M H; Greyling, Arno; Draijer, Richard; Hopman, Maria T E; Thijssen, Dick H J

2014-02-01

Tea consumption is associated with reduced cardiovascular risk. Previous studies found that tea flavonoids work through direct effects on the vasculature, leading to dose-dependent improvements in endothelial function. Cardioprotective effects of regular tea consumption may relate to the prevention of endothelial ischaemia-reperfusion (IR) injury. Therefore, we examined the effect of black tea consumption on endothelial function and the ability of tea to prevent IR injury. In a randomized, crossover study, 20 healthy subjects underwent 7 days of tea consumption (3 cups per day) or abstinence from tea. We examined brachial artery (BA) endothelial function via flow-mediated dilation (FMD), using high resolution echo-Doppler, before and 90 min after tea or hot water consumption. Subsequently, we followed a 20-min ischaemia and 20-min reperfusion protocol of the BA after which we measured FMD to examine the potential of tea consumption to protect against IR injury. Tea consumption resulted in an immediate increase in FMD% (pre-consumption: 5.8 ± 2.5; post-consumption: 7.2 ± 3.2; p FMD (p FMD. However, the impact of the IR protocol on FMD was not influenced by tea consumption. Therefore, the cardioprotective association of tea ingestion relates to a direct effect of tea on the endothelium in humans in vivo.

Glial and neuronal control of brain blood flow

DEFF Research Database (Denmark)

Attwell, David; Buchan, Alastair M; Charpak, Serge

2010-01-01

Blood flow in the brain is regulated by neurons and astrocytes. Knowledge of how these cells control blood flow is crucial for understanding how neural computation is powered, for interpreting functional imaging scans of brains, and for developing treatments for neurological disorders. It is now...... in our understanding of cerebral blood flow control have important implications for the development of new therapeutic approaches....

Analysis of temporal dynamics in imagery during acute limb ischemia and reperfusion

Science.gov (United States)

Irvine, John M.; Regan, John; Spain, Tammy A.; Caruso, Joseph D.; Rodriquez, Maricela; Luthra, Rajiv; Forsberg, Jonathon; Crane, Nicole J.; Elster, Eric

2014-03-01

Ischemia and reperfusion injuries present major challenges for both military and civilian medicine. Improved methods for assessing the effects and predicting outcome could guide treatment decisions. Specific issues related to ischemia and reperfusion injury can include complications arising from tourniquet use, such as microvascular leakage in the limb, loss of muscle strength and systemic failures leading to hypotension and cardiac failure. Better methods for assessing the viability of limbs/tissues during ischemia and reducing complications arising from reperfusion are critical to improving clinical outcomes for at-risk patients. The purpose of this research is to develop and assess possible prediction models of outcome for acute limb ischemia using a pre-clinical model. Our model relies only on non-invasive imaging data acquired from an animal study. Outcome is measured by pathology and functional scores. We explore color, texture, and temporal features derived from both color and thermal motion imagery acquired during ischemia and reperfusion. The imagery features form the explanatory variables in a model for predicting outcome. Comparing model performance to outcome prediction based on direct observation of blood chemistry, blood gas, urinalysis, and physiological measurements provides a reference standard. Initial results show excellent performance for the imagery-base model, compared to predictions based direct measurements. This paper will present the models and supporting analysis, followed by recommendations for future investigations.

Intraperitoneal curcumin decreased lung, renal and heart injury in abdominal aorta ischemia/reperfusion model in rat.

Science.gov (United States)

Aydin, Mehmet Salih; Caliskan, Ahmet; Kocarslan, Aydemir; Kocarslan, Sezen; Yildiz, Ali; Günay, Samil; Savik, Emin; Hazar, Abdussemet; Yalcin, Funda

2014-01-01

Previous studies have demonstrated that curcumin (CUR) has protective effects against ischemia reperfusion injury to various organs. We aimed to determine whether CUR has favorable effects on tissues and oxidative stress in abdominal aorta ischemia-reperfusion injury. Thirty rats were divided into three groups as sham, control and treatment (CUR) group. Control and CUR groups underwent abdominal aorta ischemia for 60 min followed by a 120 min period of reperfusion. In the CUR group, CUR was given 5 min before reperfusion at a dose of 200 mg/kg via an intraperitoneal route. Total antioxidant capacity (TAC), total oxidative status (TOS), and oxidative stress index (OSI) in blood serum were measured, and lung, renal and heart tissue histopathology were evaluated with light microscopy. TOS and OSI activity in blood samples were statistically decreased in sham and CUR groups compared to the control group (p OSI). Renal, lung, heart injury scores of sham and CUR groups were statistically decreased compared to control group (p model. Copyright © 2014 Surgical Associates Ltd. Published by Elsevier Ltd. All rights reserved.

Regional cerebral blood flow in the patient with brain tumor

International Nuclear Information System (INIS)

Tsuchida, Shohei

1993-01-01

Regional cerebral blood flow (rCBF) was measured with xenon-enhanced CT (Xe-CT) in 21 cases of intracranial tumors (13 meningiomas, 5 gliomas, 3 metastatic brain tumors). Peritumoral edema was graded as mild, moderate or severe based on the extent of edema on CT and MRI. According to intratumoral blood flow distribution patterns, three patterns were classified as central type with relatively high blood flow at the center of the tumor, homogeneous type with an almost homogeneous blood flow distribution, and marginal type with relatively high blood flow at the periphery of the tumor. High grade astrocytoma and metastatic brain tumor showed marginal type blood flow and moderate or severe edema except in one case. Five meningiomas with severe peritumoral edema revealed marginal type blood flow and four with mild peritumoral edema showed central type blood flow, except for one case. No correlation was found between the extent of peritumoral edema and histological subtype, tumor size, location, duration of clinical history, vascularization on angiogram, and mean blood flow in the tumor. These results suggest that blood flow distribution patterns within the tumor may affect the extension of peritumoral edema. Pre- and postoperative rCBFs were evaluated with Xe-CT and IMP-SPECT in 7 cases, mean rCBF of peritumoral edema was 6.2 ml/100 g/min preoperatively, and discrepancy between rCBF on Xe-CT and that on IMP-SPECT was shown in the remote cortical region ipsilateral to the tumor. Postoperative rCBF revealed an improved blood flow in both adjacent and remote areas, suggesting that the decreased blood flow associated with brain tumors might be relieved after surgery. (author) 53 refs

MR measurement of coronary arterial blood flow velocity. Evaluation of age, stenosis and drugs as factors affecting coronary blood flow

International Nuclear Information System (INIS)

Taoka, Yoshiaki; Harada, Masafumi; Nishitani, Hiromu; Yukinaka, Michiko; Nomura, Masahiro

1998-01-01

Coronary arterial blood flow velocity was measured using MRI. Two types of phase contrast methods were used for the measurements, one of which exhibited good resolving power whereas the other provided more distinct images acquired while the subject patients held their breath. Before measuring coronary arterial blood flow velocity, accuracy of the two phase contrast methods was evaluated using a phantom. The results obtained with both methods largely agreed with the values obtained using the phantom. Using both methods, the patterns of coronary arterial blood flow over one cardiac cycle were essentially identical. A peak was noted in late systole or in early diastole in the right coronary artery, whereas in the left coronary artery, a peak was noted somewhat later in diastole. In healthy volunteers, no significant difference in the maximal flow velocity in the coronary arteries was found from one age group to another. Among patients with coronary arterial stenosis, coronary arterial blood flow velocity central to the area of stenosis was lower than that observed in the healthy volunteers. Coronary arterial blood flow velocity was observed to decrease after administration of isosorbide dinitrate and increased following administration of nifedipine. (author)

Mild episodes of tourniquet-induced forearm ischaemia-reperfusion injury results in leukocyte activation and changes in inflammatory and coagulation markers

Directory of Open Access Journals (Sweden)

Bastawrous Salah S

2007-05-01

Full Text Available Abstract Background Monocytes and neutrophils are examples of phagocytic leukocytes, with neutrophils being considered as the 'chief' phagocytic leukocyte. Both monocytes and neutrophils have been implicated to play a key role in the development of ischaemia-reperfusion injury, where they are intrinsically involved in leukocyte-endothelial cell interactions. In this pilot study we hypothesised that mild episodes of tourniquet induced forearm ischaemia-reperfusion injury results in leukocyte activation and changes in inflammatory and coagulation markers. Methods Ten healthy human volunteers were recruited after informed consent. None had any history of cardiovascular disease with each subject volunteer participating in the study for a 24 hour period. Six venous blood samples were collected from each subject volunteer at baseline, 10 minutes ischaemia, 5, 15, 30, 60 minutes and 24 hours reperfusion, by means of a cannula from the ante-cubital fossa. Monocyte and neutrophil leukocyte sub-populations were isolated by density gradient centrifugation techniques. Leukocyte trapping was investigated by measuring the concentration of leukocytes in venous blood leaving the arm. The cell surface expression of CD62L (L-selectin, CD11b and the intracellular production of hydrogen peroxide (H2O2 were measured via flow cytometry. C-reactive protein (CRP was measured using a clinical chemistry analyser. Plasma concentrations of D-dimer and von Willebrand factor (vWF were measured using enzyme-linked fluorescent assays (ELFA. Results During ischaemia-reperfusion injury, there was a decrease in CD62L and an increase in CD11b cell surface expression for both monocytes and neutrophils, with changes in the measured parameters reaching statistical significance (p =2O2 production by leukocyte sub-populations, which was measured as a marker of leukocyte activation. Intracellular production of H2O2 in monocytes during ischaemia-reperfusion injury reached statistical

Frequency encoding in renal blood flow regulation

DEFF Research Database (Denmark)

Marsh, D.J.; Sosnovtseva, Olga; Pavlov, A.N.

2005-01-01

With a model of renal blood flow regulation, we examined consequences of tubuloglomerular feedback (TGF) coupling to the myogenic mechanism via voltage-gated Ca channels. The model reproduces the characteristic oscillations of the two mechanisms and predicts frequency and amplitude modulation...... of the myogenic oscillation by TGF. Analysis by wavelet transforms of single-nephron blood flow confirms that both amplitude and frequency of the myogenic oscillation are modulated by TGF. We developed a double-wavelet transform technique to estimate modulation frequency. Median value of the ratio of modulation...... TGF cycle to the next. We used a blood pressure signal recorded by telemetry from a conscious rat as the input to the model. Blood pressure fluctuations induced variability in the modulation records similar to those found in the nephron blood flow results. Frequency and amplitude modulation can...

X-ray PIV measurements of blood flows without tracer particles

International Nuclear Information System (INIS)

Kim, Guk Bae; Lee, Sang Joon

2006-01-01

We analyzed the non-Newtonian flow characteristics of blood moving in a circular tube flow using an X-ray PIV method and compared the experimental results with hemodynamic models. The X-ray PIV method was improved for measuring quantitative velocity fields of blood flows using a coherent synchrotron X-ray. Without using any contrast media, this method can visualize flow pattern of blood by enhancing the phase-contrast and interference characteristics of blood cells. The enhanced X-ray images were achieved by optimizing the sample-to-scintillator distance, the sample thickness, and hematocrit in detail. The quantitative velocity fields of blood flows inside opaque conduits were obtained by applying a two-frame PIV algorithm to the X-ray images of the blood flows. The measured velocity data show typical features of blood flow such as the yield stress and shear-thinning effects. (orig.)

Subcutaneous blood flow during insulin-induced hypoglycaemia

DEFF Research Database (Denmark)

Hilsted, J; Madsbad, S; Sestoft, L

1982-01-01

Subcutaneous blood flow was measured preceding insulin-induced hypoglycaemia, at the onset of hypoglycaemic symptoms and 2 h later in juvenile diabetics with and without autonomic neuropathy and in normal males. In all groups subcutaneous blood flow decreased at the onset of hypoglycaemic symptom...

Blood flow velocity in migraine attacks - a transcranial Doppler study

International Nuclear Information System (INIS)

Zwetsloot, C.P.; Caekebeke, J.F.V.; Jansen, J.C.; Odink, J.; Ferrari, M.D.

1991-01-01

A pulsed Doppler device was used to measure blood flow velocities in the common carotid artery, the extracranial part of the internal carotid artery, the external carotid artery, the middle cerebral artery, and the anterior cerebral artery in 31 migraneurs without aura (n=27) and with aura (n=4), both during and ouside an attack. The aims were to compare blood flow velocity during and between migraine attacks and to study asymmetries of the blood flow velocity. Compared with blood flow velocity values obtained in the attack-free interval, blood flow velocity was lower during attacks without aura in both common carotid arteries, but not in the other extra- and intracranial vessels which were examined. However, during attacks of migraine with aura, blood flow velocity tended to be lower in all examined vessels. There were no asymmetries of the blood flow velocity. It is suggested that during migraine attacks without aura there is a dissociation in blood flow regulation in the common carotid and middle cerebral arteries. 20 refs., 2 tabs

Blood flow velocity in migraine attacks - a transcranial Doppler study

Energy Technology Data Exchange (ETDEWEB)

Zwetsloot, C.P.; Caekebeke, J.F.V.; Jansen, J.C.; Odink, J.; Ferrari, M.D. (Rijksuniversiteit Leiden (Netherlands))

1991-05-01

A pulsed Doppler device was used to measure blood flow velocities in the common carotid artery, the extracranial part of the internal carotid artery, the external carotid artery, the middle cerebral artery, and the anterior cerebral artery in 31 migraneurs without aura (n=27) and with aura (n=4), both during and ouside an attack. The aims were to compare blood flow velocity during and between migraine attacks and to study asymmetries of the blood flow velocity. Compared with blood flow velocity values obtained in the attack-free interval, blood flow velocity was lower during attacks without aura in both common carotid arteries, but not in the other extra- and intracranial vessels which were examined. However, during attacks of migraine with aura, blood flow velocity tended to be lower in all examined vessels. There were no asymmetries of the blood flow velocity. It is suggested that during migraine attacks without aura there is a dissociation in blood flow regulation in the common carotid and middle cerebral arteries. 20 refs., 2 tabs.

The effect of ventricular assist devices on cerebral blood flow and blood pressure fractality

International Nuclear Information System (INIS)

Bellapart, Judith; Fraser, John F; Chan, Gregory S H; Tzeng, Yu-Chieh; Ainslie, Philip N; Dunster, Kimble R; Barnett, Adrian G; Boots, Rob

2011-01-01

Biological signals often exhibit self-similar or fractal scaling characteristics which may reflect intrinsic adaptability to their underlying physiological system. This study analysed fractal dynamics of cerebral blood flow in patients supported with ventricular assist devices (VAD) to ascertain if sustained modifications of blood pressure waveform affect cerebral blood flow fractality. Simultaneous recordings of arterial blood pressure and cerebral blood flow velocity using transcranial Doppler were obtained from five cardiogenic shock patients supported by VAD, five matched control patients and five healthy subjects. Computation of a fractal scaling exponent (α) at the low-frequency time scale by detrended fluctuation analysis showed that cerebral blood flow velocity exhibited 1/f fractal scaling in both patient groups (α = 0.95 ± 0.09 and 0.97 ± 0.12, respectively) as well as in the healthy subjects (α = 0.86 ± 0.07). In contrast, fluctuation in blood pressure was similar to non-fractal white noise in both patient groups (α = 0.53 ± 0.11 and 0.52 ± 0.09, respectively) but exhibited 1/f scaling in the healthy subjects (α = 0.87 ± 0.04, P < 0.05 compared with the patient groups). The preservation of fractality in cerebral blood flow of VAD patients suggests that normal cardiac pulsation and central perfusion pressure changes are not the integral sources of cerebral blood flow fractality and that intrinsic vascular properties such as cerebral autoregulation may be involved. However, there is a clear difference in the fractal scaling properties of arterial blood pressure between the cardiogenic shock patients and the healthy subjects

Dynamic gadolinium-enhanced MRI evaluation of porcine femoral head ischemia and reperfusion

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Schneider, T. [Clinic for Orthopaedics and Sports Traumatology, Dreifaltigkeits-Krankenhaus GmbH, Aachener Str. 445-449, 50933 Koeln (Germany); Drescher, W. [Department of Orthopaedics, Christian Albrechts University, Kiel (Germany); Becker, C. [Department of Orthopaedics, Heinrich Heine University, Duesseldorf (Germany); Sangill, R.; Stoedkilde-Joergensen, H. [Institute for Magnetic Resonance Imaging Tomography, University of Aarhus, Skejby Hospital, Aarhus (Denmark); Heydthausen, M. [Computing Center, Heinrich Heine University, Duesseldorf (Germany); Hansen, E.S.; Buenger, C. [Spine Section, Department of Orthopaedics, University of Aarhus (Denmark)

2003-02-01

To examine the potential of gadolinium (Gd)-enhanced dynamic MRI in the detection of early femoral head ischemia. Furthermore, to apply a three-compartment model to achieve a clinically applicable MR index for femoral head perfusion during the steady state and arterial hip joint tamponade.Design and materials In a porcine model femoral head perfusion was measured by radioactive tracer microspheres and by using a dynamic Gd-enhanced MRI protocol. Femoral head perfusion measurements and MRI tests were performed unilaterally before, during and after the experimentally induced ischemia of one of the hip joints. Ischemia was induced by increasing intra-articular pressure to 250 mmHg. All pigs showed ischemia of the femoral head epiphysis under hip joint tamponade followed by reperfusion to the same level as before joint tamponade. In two cases perfusion after removal of tamponade continued to be low. In dynamic MRI measurements increases in signal intensity were seen after intravenous infusion of Gd-DTPA, followed by a slow decrease in signal intensity. The signal-intensity curve during femoral head ischemia had a minor increase. Also the coefficient determined was a helpful indicator of femoral head ischemia. Femoral head blood flow as measured by microspheres fell significantly under joint tamponade. Early detection of this disturbed regional blood flow was possible using a dynamic MRI procedure. A biomathematical model resulted from the evaluation of the intervals of signal intensity over time which allows detection of bone blood flow changes at a very early stage. Using this new method earlier detection of femoral head necrosis may be possible. (orig.)

The effect of ultrasound on arterial blood flow: 1. Steady fully developed flow

International Nuclear Information System (INIS)

Bestman, A.R.

1990-12-01

The paper models the effects of ultrasound heating of the tissues and the resultant perturbation on blood flow in the arteries and veins. It is assumed that the blood vessel is rigid and the undisturbed flow is fully developed. Acoustical perturbation on this Poiseuille flow, for the general three-dimensional flow with heat transfer in an infinitely long pipe is considered. Closed form analytical solutions are obtained to the problem. It is discovered that the effects of the ultrasound heating are concentrated at the walls of the blood vessels. (author). 4 refs

Renal blood flow in sepsis: a complex issue

OpenAIRE

Molitoris, Bruce A

2005-01-01

The clinical complexity of sepsis and the regional variability in renal blood flow present a difficult challenge for the clinician or investigator in understanding the role and clinical importance of reduced blood flow in the pathophysiology of sepsis-induced acute renal failure. Understanding the role of regional microvasculature flow and interactions between endothelium and white blood cells in the local delivery of oxygen and substrates is of critical importance. Therefore, measuring total...

Measurement of Finger Blood Flow in Raynauds Phenomenon by Radionuclide Angiography

International Nuclear Information System (INIS)

Lim, Sang Moo; Chung, June Key; Lee, Myung Chul; Kim, Sang Joon; Choi, Sung Jae; Koh, Chang Soon

1987-01-01

In Raynauds phenomenon, the authors measured finger blood flow after ice water exposure by analyzing the time activity curve of radionuclide angiography on both hands. The results were as follows: 1) The digital blood flow did not decrease after ice water exposure in normal subjects. 2) In the patients with Raynauds phenomenon, there were two groups: the one had decreased digital blood flow after cold exposure, and the other had paradoxically increased digital blood flow after cold exposure. 3) There was no difference in the digital blood flow of hand in room temperature between the normal and the patients with reduced digital blood flow after cold exposure, but the digital blood flow of the hand in room temperature was markedly reduced in the patients with paradoxically increased flow after cold exposure. 4) In the static image the difference was not significant in comparison with the dynamic study, because it represents pooling of the blood in the vein rather than flow. 5) After the treatment with nifedipine, the digital blood flow increased. In conclusion, the radionuclide angiography was useful in measuring the digital blood flow in Raynauds phenomenon, and further studies with various drugs is expected.

Blood carbonyl protein measurement as a specific oxidative stress biomarker after intestinal reperfusion in rats Dosagem da proteína carbonilada sanguínea como biomarcador específico do estresse oxidativo após reperfusão intestinal em ratos

Directory of Open Access Journals (Sweden)

Márcio José Jamel

2010-02-01

Full Text Available PURPOSE: An experimental study was performed to investigate the use of protein carbonyl group as a specific biological marker for oxidative stress in a rat model of intestinal ischaemia-reperfusion. METHODS: Twenty four male Wistar rats were randomly distributed into three groups with eight animals each: Group 1 - Control group; Group 2 - Sham; Group 3 - Intestinal ischaemia by clamping ileal branches of the superior mesenteric artery for one hour, followed by another hour of reperfusion. Blood samples were taken in order to analyze the protein carbonyl level by Slot blotting assay. RESULTS: In group 3 a significant increase of protein carbonyl level was observed if compared to the homogenous levels of groups 1 and 2. CONCLUSION: From the results it may be concluded that the protein carbonylation may be used as a specific marker for measuring oxidative stress in rat intestinal reperfusion model.OBJETIVO: Realizou-se um estudo experimental com a finalidade de investigar o uso da proteína carbonilada como um marcador biológico específico do estresse oxidativo em um modelo de isquemia e reperfusão intestinal, em ratos. MÉTODOS: Vinte e quarto ratos da linhagem Wistar, machos foram distribuídos, aleatoriamente, em três grupos compostos por oito animais cada: Grupo 1 - Controle; Grupo 2 - Simulação e Grupo 3 - Submetido à isquemia, mediante clampeamento de ramos ileais da artéria mesentérica superior por uma hora, seguida de reperfusão, por igual período. Amostras sanguíneas obtidas foram utilizadas para analise dos níveis de proteína carbonilada, através do método Slot blotting. RESULTADOS: No grupo 3 houve uma elevação significante da concentração de proteína carbonilada sérica se comparada aos níveis sanguíneos homogêneos encontrados nos grupos 1 e 2. CONCLUSÃO: Fundamentado nos resultados é possível concluir que, a carbonilação protéica pode ser utilizada como um marcador específico para a mensuração do

The multi-slice CT perfusion imaging in evaluating the prevention and treatment by edaravone on lung ischemia-reperfusion injury after pulmonary thromboembolism

International Nuclear Information System (INIS)

Li Jianjun; Zhai Renyou; Zhang Dongpo; Huang Qiang; Dai Dingke; Yu Ping; Bao Na

2008-01-01

Objective: To evaluate the multi-slice CT perfusion imaging in investigating whether edaravone can prevent and treat pulmonary thromboembolism ischemia-reperfusion injury (PTE-IRI). Methods: Twenty mongrel canines were included. A Swan-Ganz catheter was introduced into the right internal jugular vein using the Seldinger technique, and then was inserted into the pulmonary artery. Balloon occlusion of the right inferior lobe pulmonary artery for 4 h was followed by removing catheter and 4 h o reperfusion. Animals were divided into four groups of A (no edaravone during ischenmia and reperfusion), B (edaravone used only during ischemia), C (edaravone used during both ischemia and reperfusion) and D group (edaravone used only during reperfusion) (n=5 per group). Every group was divided into three time points including before ischemia, 4 h after ischemia and 4 h after reperfusion. CT scan and CT perfusion were performed at the three time points. The blood flow (BF), blood volume (BV) and mean transit time (MTT) of the bilateral inferior regional lung parenchyma were measured with the software of perfusion 3. Results: CT examination showed pulmonary edema in the right inferior lung lobe at 4 h after reperfusion. (1) The BF and MTT of A, B, C and D group were[(259.4±15.7)ml·min -1 ·100 g -1 , (293.7± 7.9) ml·min -1 ·100 g -1 , (379.4±14.5)ml·min -1 ·100 g -1 , (382.5±16.6)ml·min -1 ·. 100 g -1 ] and [(3.1±0.2)s, (2.6±0.2)s, (2.2±0.1)s, (1.9±0.2)s] respectively at 4 h after reperfusion. The BF and MTT were statistically different (P 0.05) at 4 h after reperfusion, but the BV was not statistically different between groups (P>0.05). (2) The BF [(397.2± 19.2)ml·min -1 ·100 g -1 and (259.4±15.7) ml·min -1 ·100 g -1 in group A, (393.2±16.1) ml· min -1 ·100 g -1 and (293.7±7.9) ml·min -1 ·100 g -1 in group B] and MTF [(1.8±0.1)s and (3.1±0.2) s in group A, (1.8±0.2) s and (2.6±0.2) s in group B] were statistically different (P 0.05) between groups

Discussion on the treatment of cerebral ischemia-reperfusion injuries following intra-arterial thrombolysis

International Nuclear Information System (INIS)

Tian Hong; Song Chuan; Fan Ruxiong; Zhou Huchuan; Zhang Yubo; Zang Qiaoli; Zhang Yunquan; Liu Lei

2011-01-01

Objective: To investigate the therapeutic method of cerebral ischemia-reperfusion injuries occurred after arterial thrombolytic therapy for acute cerebral infarction. Methods: Thirty-five patients, encountered in authors' Department since Oct. 2005, with cerebral ischemia-reperfusion injuries, which occurred after thrombolytic therapy by using arterial perfusion of urokinase for acute cerebral infarction, were enrolled in this study. The clinical data were retrospectively analyzed. Results: After the thrombolytic therapy, completer or partial recanalization of the occluded cerebral arteries was obtained in 33 cases, while secondary cerebral hemorrhage occurred in 13 cases, of whom cerebral parenchyma bleeding was seen in 2 and hemorrhagic infarction in 11. Different degrees of cerebral edema were found in all 33 cases. Among them significant shift of the midline structures was detected in 18 (54.5%), which was manifested clinically as the worsening of disturbance of consciousness. Strict control of blood pressure, prompt adjustment of dehydration medication, strengthening the cerebral protection measures, cerebral decompression by fenestration, etc. were carried out. All the patients took a turn for the better and were out of danger with remarkable improvement of neurological functions except one patient who died from massive intracerebral hemorrhage. Conclusion: Usually, different degrees of reperfusion injuries will develop after thrombolytic therapy for cerebral arterial infarction. Strictly controlling blood pressure, promptly adjusting dehydration medication and strengthening cerebral protection are the keys to reduce the severity of cerebral reperfusion injuries. (authors)

Skeletal blood flow, iliac histomorphometry, and strontium kinetics in osteoporosis: a relationship between blood flow and corrected apposition rate

International Nuclear Information System (INIS)

Reeve, J.; Arlot, M.; Wootton, R.; Edouard, C.; Tellez, M.; Hesp, R.; Green, J.R.; Meunier, P.J.

1988-01-01

In 20 untreated patients with idiopathic or postmenopausal osteoporosis, kinetic studies of skeletal blood flow (using 18 F) and bone turnover (using 85 Sr) were combined with dynamic histomorphometry performed on transiliac biopsies taken within 6 weeks of each other. In 8 patients the combined studies were repeated after treatment. A further 5 patients were studied only while receiving treatment. As expected, skeletal blood flow measured by 18 F correlated with an index of 85 Sr uptake into the exchangeable pools of bone. Additionally and independently, skeletal blood flow correlated with an index of the work rate of the osteoblasts in each multicellular unit of bone (the corrected apposition rate of Parfitt). These correlations were statistically significant in both the untreated patients (P less than 0.05) and the whole group (P less than 0.001). Further indices related to bone turnover at the level of the skeleton as a whole were significantly associated with skeletal blood flow only in the combined group

The role of blood flow in chronic duodenal ulcer

Energy Technology Data Exchange (ETDEWEB)

Gompertz, R.H.K.; Mathie, R.T.; Michalowski, A.S.; Spencer, J.; Baron, J.H.; Williamson, R.C.N.

1996-01-01

Changes in gastroduodenal blood flow have been implicated in the pathogenesis of duodenal ulcer. The authors have studied duodenal blood flow during the development of an acute to chronic duodenal ulcer by using the abscopal model, in which ulcers are generated as an indirect effect of lower mediastinal irradiation. Female CFLP mice were randomly allocated to one of three groups. Irradiated ``controls`` received 18 Gy 250 kV X-rays to the upper mediastinum. The lower mediastinum group received the same dose of irradiation, which has been shown to induce typical chronic duodenal ulcers in 45% of animals so treated. Animals were studied by means of radiolabelled microspheres 3 or 7 days later. Proximal duodenal blood flow specifically was reduced by 32% in the lower mediastinum group compared with irradiated controls at 7 days. There was no significant difference in blood flow to the stomach and to the distal duodenum. The decrease in proximal duodenal blood flow in the lower mediastinum group did not differ in the five animals that developed ulcer compared with the seven that did not. Although, there is an overall decrease in duodenal blood flow associated with chronic duodenal ulcer, reduced blood flow may not explain individual susceptibility to ulceration. 21 refs., 1 fig., 2 tabs.

Corticosteroid Reduces Blood Flow to Femoral Heads in Rabbits.

Science.gov (United States)

Hou, S.M.; Liu, T.K.; Kao, M.C.

1994-12-01

Avascular necrosis of the femoral head is one of the common problems in orthopedic practice in Taiwan. The subchondral bone loses its blood supply which weakens its biomechanical support. Steroid overuse is one of many possible etiologies in reducing blood flow to the femoral head. Laser Doppler velocimeter is a precise monitor of regional blood flow of bone which is expressed in perfusion units (PU). In the control group the rabbits were injected with normal saline and there were no statistical differences between blood flow to the right hip (39.26 +/- 5.64 PU) and left hip (38.58 +/- 4.35 PU). In group B a weekly injection of methylprednisolone into rabbits for 6 weeks demonstrated the reduction of blood flow of femoral head (24.74 +/- 3.13 PU) by the laser Doppler velocimeter. The flow decreased further (15.93 +/- 2.33 PU) by 12 weeks of steroid treatment. In group C after a weekly injection of steroid for 6 weeks the flow became 31.63 +/- 4.79 PU. The steroid was then discontinued for 3 weeks and the flow was 34.6 +/- 1.34 PU. In group D the blood flow was 25.89 +/- 4.01 PU after 6 weeks of steroid treatment and we stopped the steroid for 6 weeks, the blood flow became 29.86 +/- 2.59 PU. The merit of our experiment established a model of study in avascular necrosis of the femoral head in rabbits. Copyright 1994 S. Karger AG, Basel

Laser Doppler flowmetry for bone blood flow measurement: correlation with microsphere estimates and evaluation of the effect of intracapsular pressure on femoral head blood flow

International Nuclear Information System (INIS)

Swiontkowski, M.F.; Tepic, S.; Perren, S.M.; Moor, R.; Ganz, R.; Rahn, B.A.

1986-01-01

Laser Doppler flowmetry (LDF) was used to measure bone blood flow in the rabbit femoral condyles. To correlate the LDF output signal blood cell flux to in vivo blood flow, simultaneous measurements using LDF and 85 Sr-labeled microspheres were made in an adult rabbit model. There was no correlation between the two methods for blood flow in the femoral condyles and the correlation between the two methods for blood flow in the femoral head does not achieve statistical significance. An LDF signal of 0.4 V was approximately equal to a microsphere measured flow rate of 0.4 ml blood/g bone/min. The strength of the correlation in the latter case may have been affected by (a) large arteriovenous shunts, (b) inadequate mixing of the microspheres with a left ventricular injection, and (c) insufficient numbers of microspheres present in the bone samples. When LDF was used to evaluate the effect of elevated intracapsular pressure on femoral head blood flow in skeletally mature rabbits, femoral head subchondral bone blood flow declined with increasing intracapsular pressure from a baseline value of 0.343 +/- 0.036 to a value of 0.127 +/- 0.27 at 120 cm of water pressure. The decline in femoral head blood flow was statistically significant at pressures of 40 cm of water or higher (p less than 0.001), and evaluation of sections of the proximal femora made from preterminal disulphine blue injections confirmed these findings. Intracapsular tamponade has an adverse effect on femoral head blood flow beginning well below central venous pressure and should be considered in the pathophysiology of posttraumatic and nontraumatic necrosis of the femoral head. Laser Doppler flowmetry was easy to use and appears to be a reproducible technique for evaluating femoral head blood flow, offering distinct advantages over the microsphere technique for measuring bone blood flow

In vivo evaluation of femoral blood flow measured with magnetic resonance

International Nuclear Information System (INIS)

Henriksen, O.; Staahlberg, F.; Thomsen, C.; Moegelvang, J.; Persson, B.; Lund Univ.

1989-01-01

Quantitative measurements of blood flow based on magnetic resonance imaging (MRI) using conventional multiple spin echo sequences were evaluated in vivo in healthy young volunteers. Blood flow was measured using MRI in the femoral vein. The initial slope of the multiple spin echo decay curve, corrected for the T2 decay of non-flowing blood was used to calculate the blood flow. As a reference, the blood flow in the femoral artery was measured simultaneously with an invasive indicator dilution technique. T2 of non-flowing blood was measured in vivo in popliteal veins during regional circulatory arrest. The mean T2 of non-flowing blood was found to be 105±31 ms. The femoral blood flow ranged between 0 and 643 ml/min measured with MRI and between 280 and 531 ml/min measured by the indicator dilution technique. There was thus poor agreement between the two methods. The results indicate that in vivo blood flow measurements made with MRI based on wash-out effects, commonly used in multiple spin echo imaging, do not give reliable absolute values for blood flow in the femoral artery or vein. (orig.)

Sequential topographical portrayal of myocardial blood flow

Energy Technology Data Exchange (ETDEWEB)

Richeson, J.F.; Waag, R.C.; Zwierzynski, D.; Schenk, E.A. (Univ. of Rochester School of Medicine and Dentistry, NY (USA))

1989-08-01

Methods to portray myocardial blood flow in a two-dimensional continuum are advantageous in that they allow blood flow history to be overlaid on histological or histochemical descriptions of the consequences of ischemia. We describe here autoradiographic methods that allow such portrayals at three separate times during the evolution of ischemic injury. A computer-based image-analysis system was used to derive such flow maps by taking advantage of the physical characteristics of radioactive isotopes.

A polymeric micelle magnetic resonance imaging (MRI) contrast agent reveals blood-brain barrier (BBB) permeability for macromolecules in cerebral ischemia-reperfusion injury.

Science.gov (United States)

Shiraishi, Kouichi; Wang, Zuojun; Kokuryo, Daisuke; Aoki, Ichio; Yokoyama, Masayuki

2017-05-10

Blood-brain barrier (BBB) opening is a key phenomenon for understanding ischemia-reperfusion injuries that are directly linked to hemorrhagic transformation. The recombinant human tissue-type plasminogen activator (rtPA) increases the risk of symptomatic intracranial hemorrhages. Recent imaging technologies have advanced our understanding of pathological BBB disorders; however, an ongoing challenge in the pre-"rtPA treatment" stage is the task of developing a rigorous method for hemorrhage-risk assessments. Therefore, we examined a novel method for assessment of rtPA-extravasation through a hyper-permeable BBB. To examine the image diagnosis of rtPA-extravasation for a rat transient occlusion-reperfusion model, in this study we used a polymeric micelle MRI contrast-agent (Gd-micelles). Specifically, we used two MRI contrast agents at 1h after reperfusion. Gd-micelles provided very clear contrast images in 15.5±10.3% of the ischemic hemisphere at 30min after i.v. injection, whereas a classic gadolinium chelate MRI contrast agent provided no satisfactorily clear images. The obtained images indicate both the hyper-permeable BBB area for macromolecules and the distribution area of macromolecules in the ischemic hemisphere. Owing to their large molecular weight, Gd-micelles remained in the ischemic hemisphere through the hyper-permeable BBB. Our results indicate the feasibility of a novel clinical diagnosis for evaluating rtPA-related hemorrhage risks. Copyright © 2017 Elsevier B.V. All rights reserved.

Collateral sources of costal and crural diaphragmatic blood flow

International Nuclear Information System (INIS)

Lockhat, D.; Magder, S.; Roussos, C.

1985-01-01

We measured the contribution of aortic, internal mammary, and intercostal arteries to the blood flow to the costal and crural segments of the diaphragm and other respiratory muscles in seven dogs breathing against a fixed inspiratory elastic load. We used radiolabeled microspheres to measure the blood flow with control circulation, occlusion of the aorta distal to the left subclavian artery, combined occlusion of the aorta and both internal mammary arteries, and occlusion of internal mammary arteries alone. With occlusion of the aorta distal to the left subclavian artery, blood flow to the crural diaphragm decreased from 40.3 to 23.5 ml . min-1 X 100 g-1, whereas costal flow did not change significantly (from 41.7 to 38.1 ml . min-1 . 100 g-1). Blood flows to the sternomastoid and scalene muscles (above the occlusion) increased by 200 and 340%, respectively, whereas flows to the other respiratory muscles did not change significantly. Blood flows to organs above the occlusion either remained unchanged or increased, whereas flows to those below the occlusion all decreased. When the internal mammary artery was also occluded, flows to the crural segment decreased further to 12.1 and costal flow decreased to 20.4 ml X min-1 X 100 g-1. Internal mammary arterial occlusion alone in two dogs had no effect on diaphragmatic flow. In conclusion, intercostal collateral vessels are capable of supplying a significant proportion of blood flow to both segments of the diaphragm but the costal segment is better served than the crural segment

Curcumin and dexmedetomidine prevents oxidative stress and renal injury in hind limb ischemia/reperfusion injury in a rat model.

Science.gov (United States)

Karahan, M A; Yalcin, S; Aydogan, H; Büyükfirat, E; Kücük, A; Kocarslan, S; Yüce, H H; Taskın, A; Aksoy, N

2016-06-01

Curcumin and dexmedetomidine have been shown to have protective effects in ischemia-reperfusion injury on various organs. However, their protective effects on kidney tissue against ischemia-reperfusion injury remain unclear. We aimed to determine whether curcumin or dexmedetomidine prevents renal tissue from injury that was induced by hind limb ischemia-reperfusion in rats. Fifty rats were divided into five groups: sham, control, curcumin (CUR) group (200 mg/kg curcumin, n = 10), dexmedetomidine (DEX) group (25 μg/kg dexmedetomidine, n = 10), and curcumin-dexmedetomidine (CUR-DEX) group (200 mg/kg curcumin and 25 μg/kg dexmedetomidine). Curcumin and dexmedetomidine were administered intraperitoneally immediately after the end of 4 h ischemia, just 5 min before reperfusion. The extremity re-perfused for 2 h and then blood samples were taken and total antioxidant capacity (TAC), total oxidative status (TOS) levels, and oxidative stress index (OSI) were measured, and renal tissue samples were histopathologically examined. The TAC activity levels in blood samples were significantly lower in the control than the other groups (p OSI were found to be significantly increased in the control group compared to others groups (p model.

Vascular structure determines pulmonary blood flow distribution

Science.gov (United States)

Hlastala, M. P.; Glenny, R. W.

1999-01-01

Scientific knowledge develops through the evolution of new concepts. This process is usually driven by new methodologies that provide observations not previously available. Understanding of pulmonary blood flow determinants advanced significantly in the 1960s and is now changing rapidly again, because of increased spatial resolution of regional pulmonary blood flow measurements.

Blood Cell Interactions and Segregation in Flow

OpenAIRE

Munn, Lance L.; Dupin, Michael M.

2008-01-01

For more than a century, pioneering researchers have been using novel experimental and computational approaches to probe the mysteries of blood flow. Thanks to their efforts, we know that blood cells generally prefer to migrate to the axis of flow, that red and white cells segregate in flow, and that cell deformability and their tendency to reversibly aggregate contribute to the non-Newtonian nature of this unique fluid. All of these properties have beneficial physiological consequences, allo...

Measurement of limb blood flow using technetium-labelled red blood cells

Energy Technology Data Exchange (ETDEWEB)

Parkin, A; Robinson, P.J.; Wiggins, P.A.; Leveson, S.H.; Salter, M.C.P.; Matthews, I.F.; Ware, F.M.

1986-05-01

A method for measuring blood flow below the knee during reactive hyperaemia induced by 3 min of arterial occlusion has been developed. Subjects are positioned with lower limbs within the field of view of a gamma camera and pneumatic cuffs are placed below the knees to isolate the blood and induce a hyperaemic response. The remaining blood pool is labelled with /sup 99/Tcsup(m)-labelled red cells. Blood flows have been derived from the initial gradients of time-activity curves and from equilibrium blood sampling. The technique has been validated using a tissue-equivalent leg phantom and peristaltic pump. The method has been applied to a small group of patients with peripheral vascular disease and to normal controls. The mean value (+-SD) of limb perfusion for normal controls was found to be 16.4 +- 3.0 ml/100 ml/min and for patients with intermittent claudication was 5.1 +- 2.6 ml/100 ml/min. Flow measurements are found to correlate with clinical findings and with symptoms. Reproducibility (established by repeated measurements) is high. The method is well tolerated even by patients suffering from rest pain.

Effects of hepatic ischemia-reperfusion injury on the P-glycoprotein activity at the liver canalicular membrane and blood-brain barrier determined by in vivo administration of rhodamine 123 in rats.

Science.gov (United States)

Miah, Mohammad K; Shaik, Imam H; Bickel, Ulrich; Mehvar, Reza

2014-04-01

To investigate the effects of normothermic hepatic ischemia-reperfusion (IR) injury on the activity of P-glycoprotein (P-gp) in the liver and at the blood-brain barrier (BBB) of rats using rhodamine 123 (RH-123) as an in vivo marker. Rats were subjected to 90 min of partial ischemia or sham surgery, followed by 12 or 24 h of reperfusion. Following intravenous injection, the concentrations of RH-123 in blood, bile, brain, and liver were used for pharmacokinetic calculations. The protein levels of P-gp and some other transporters in the liver and brain were also determined by Western blot analysis. P-gp protein levels at the liver canalicular membrane were increased by twofold after 24 h of reperfusion. However, the biliary excretion of RH-123 was reduced in these rats by 26%, presumably due to IR-induced reductions in the liver uptake of the marker and hepatic ATP concentrations. At the BBB, a 24% overexpression of P-gp in the 24-h IR animals was associated with a 30% decrease in the apparent brain uptake clearance of RH-123. The pharmacokinetics or brain distribution of RH-123 was not affected by the 12-h IR injury. Hepatic IR injury may alter the peripheral pharmacokinetics and brain distribution of drugs that are transported by P-gp and possibly other transporters.

A novel dual NO-donating oxime and c-Jun N-terminal kinase inhibitor protects against cerebral ischemia-reperfusion injury in mice.

Science.gov (United States)

Atochin, Dmitriy N; Schepetkin, Igor A; Khlebnikov, Andrei I; Seledtsov, Victor I; Swanson, Helen; Quinn, Mark T; Huang, Paul L

2016-04-08

The c-Jun N-terminal kinase (JNK) has been shown to be an important regulator of neuronal cell death. Previously, we synthesized the sodium salt of 11H-indeno[1,2-b]quinoxalin-11-one (IQ-1S) and demonstrated that it was a high-affinity inhibitor of the JNK family. In the present work, we found that IQ-1S could release nitric oxide (NO) during its enzymatic metabolism by liver microsomes. Moreover, serum nitrite/nitrate concentration in mice increased after intraperitoneal injection of IQ-1S. Because of these dual actions as JNK inhibitor and NO-donor, the therapeutic potential of IQ-1S was evaluated in an animal stroke model. We subjected wild-type C57BL6 mice to focal ischemia (30min) with subsequent reperfusion (48h). Mice were treated with IQ-1S (25mg/kg) suspended in 10% solutol or with vehicle alone 30min before and 24h after middle cerebral artery (MCA) occlusion (MCAO). Using laser-Doppler flowmetry, we monitored cerebral blood flow (CBF) above the MCA during 30min of MCAO provoked by a filament and during the first 30min of subsequent reperfusion. In mice treated with IQ-1S, ischemic and reperfusion values of CBF were not different from vehicle-treated mice. However, IQ-1S treated mice demonstrated markedly reduced neurological deficit and infarct volumes as compared with vehicle-treated mice after 48h of reperfusion. Our results indicate that the novel JNK inhibitor releases NO during its oxidoreductive bioconversion and improves stroke outcome in a mouse model of cerebral reperfusion. We conclude that IQ-1S is a promising dual functional agent for the treatment of cerebral ischemia and reperfusion injury. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

A Novel Dual NO-donating Oxime and c-Jun N-terminal Kinase Inhibitor Protects Against Cerebral Ischemia–Reperfusion Injury in Mice

Science.gov (United States)

Atochin, Dmitriy N.; Schepetkin, Igor A.; Khlebnikov, Andrei I.; Seledtsov, Victor I.; Swanson, Helen; Quinn, Mark T.; Huang, Paul L.

2017-01-01

The c-Jun N-terminal kinase (JNK) has been shown to be an important regulator of neuronal cell death. Previously, we synthesized the sodium salt of 11H-indeno[1,2-b]quinoxalin-11-one (IQ-1S) and demonstrated that it was a high-affinity inhibitor of the JNK family. In the present work, we found that IQ-1S could release nitric oxide (NO) during its enzymatic metabolism by liver microsomes. Moreover, serum nitrite/nitrate concentration in mice increased after intraperitoneal injection of IQ-1S. Because of these dual actions as JNK inhibitor and NO-donor, the therapeutic potential of IQ-1S was evaluated in an animal stroke model. We subjected wild-type C57BL6 mice to focal ischemia (30 minutes) with subsequent reperfusion (48 hours). Mice were treated with IQ-1S (25 mg/kg) suspended in 10% solutol or with vehicle alone 30 minutes before and 24 hours after middle cerebral artery MCA) occlusion (MCAO). Using laser-Doppler flowmetry, we monitored cerebral blood flow (CBF) above the MCA during 30 minutes of MCAO provoked by a filament and during the first 30 minutes of subsequent reperfusion. In mice treated with IQ-1S, ischemic and reperfusion values of CBF were not different from vehicle-treated mice. However, IQ-1S treated mice demonstrated markedly reduced neurological deficit and infarct volumes as compared with vehicle-treated mice after 48 hours of reperfusion. Our results indicate that the novel JNK inhibitor releases NO during its oxidoreductive bioconversion and improves stroke outcome in a mouse model of cerebral reperfusion. We conclude that IQ-1S is a promising dual functional agent for the treatment of cerebral ischemia and reperfusion injury. PMID:26923672

Protective effect of preconditioning and adenosine pretreatment in experimental skeletal muscle reperfusion injury.

Science.gov (United States)

Papanastasiou, S; Estdale, S E; Homer-Vanniasinkam, S; Mathie, R T

1999-07-01

Prolonged ischaemia followed by reperfusion (I/R) of skeletal muscle results in significant tissue injury. Ischaemic preconditioning (IPC), achieved by repeated brief periods of I/R before prolonged ischaemia or adenosine pretreatment, can prevent I/R injury in cardiac muscle. The aim of this study was to ascertain in a rodent model if damage to skeletal muscle due to global hindlimb tourniquet-induced I/R could be similarly attenuated. Anaesthetized rats were randomized (n = 6-10 per group) to five groups: sham-operated controls; I/R (4 h of ischaemia, 2 h of reperfusion); IPC (three cycles of 10 min of ischaemia/10 min of reperfusion) alone; IPC immediately preceding I/R; or adenosine 1000 microg/kg immediately before I/R. At the end of reperfusion, biopsies were taken from the left gastrocnemius muscle for measurement of myeloperoxidase (MPO) and reduced glutathione (GSH). Before ischaemia and at the end of reperfusion, blood samples were taken for measurement of nitric oxide metabolites, tumour necrosis factor (TNF) alpha and macrophage inflammatory protein (MIP) 2. IPC before I/R resulted in lower levels of MPO (P < 0.001) and TNF-alpha (P = 0.004), and higher levels of GSH (P < 0.001) and nitric oxide metabolites (P = 0.002) than I/R alone. Adenosine had effects comparable to IPC pretreatment (P < 0.001 for MPO, P = 0.002 for GSH, P = 0.02 for nitric oxide metabolites and P = 0.001 for TNF-alpha). There was no difference in the blood pressure or the MIP-2 concentration among the groups. IPC or pretreatment with adenosine ameliorates the I/R injury of skeletal muscle.

Effects of Red Blood Cell Aggregation on the Apparent Viscosity of Blood Flow in Tubes.

Science.gov (United States)

Hitt, Darren L.; Lowe, Mary L.

1996-11-01

In arterioles and venules (20-200μ diameter), the low shear rates enable red blood cells to form aggregate structures of varying sizes and morphology. The size and distribution of the aggregates affect the flow impedance within a microvascular network; this effect may be characterized by an "apparent viscosity". In this study, we measure the apparent viscosity of blood flow in 50μ glass tubes as a function of shear rate and red blood cell volume fraction (hematocrit); for a fixed tube geometry and an imposed flow rate, the viscosity is determined by measuring the pressure drop across the tube. To correlate the apparent viscosity with the size and spatial distribution of the aggregates in the flow, video images of the flow are recorded and analyzed using power spectral techniques. Pig blood and sheep blood are used as the models for aggregating and non-aggregating blood, respectively. Supported by NSF PFF Award CTS-9253633

Collision Based Blood Cell Distribution of the Blood Flow

Science.gov (United States)

Cinar, Yildirim

2003-11-01

Introduction: The goal of the study is the determination of the energy transferring process between colliding masses and the application of the results to the distribution of the cell, velocity and kinetic energy in arterial blood flow. Methods: Mathematical methods and models were used to explain the collision between two moving systems, and the distribution of linear momentum, rectilinear velocity, and kinetic energy in a collision. Results: According to decrease of mass of the second system, the velocity and momentum of constant mass of the first system are decreased, and linearly decreasing mass of the second system captures a larger amount of the kinetic energy and the rectilinear velocity of the collision system on a logarithmic scale. Discussion: The cause of concentration of blood cells at the center of blood flow an artery is not explained by Bernoulli principle alone but the kinetic energy and velocity distribution due to collision between the big mass of the arterial wall and the small mass of blood cells must be considered as well.

The effect of sympathectomy on bone blood flow in man

International Nuclear Information System (INIS)

Lahtinen, T.; Alhava, E.M.; Hyoedynmaa, S.; Hendolin, H.; Oksala, I.

1982-01-01

The effect of lumbar sympathectomy on bone blood flow was measured in seven patients with a Xe-133 washout method. On the third postoperative day there was a significant increase of blood flow in the proximal femur and a slight increase in the proximal tibia. Two months after the operation blood flow in the proximal part of the femur was no more significantly increased but in the proximal tibia there was a significant increase. The study suggests that the positive effect of sympathectomy on bone blood flow may be of value in cases where the increase of blood flow to peripheral bones is required

Real-time direct measurement of spinal cord blood flow at the site of compression: relationship between blood flow recovery and motor deficiency in spinal cord injury.

Science.gov (United States)

Hamamoto, Yuichiro; Ogata, Tadanori; Morino, Tadao; Hino, Masayuki; Yamamoto, Haruyasu

2007-08-15

An in vivo study to measure rat spinal cord blood flow in real-time at the site of compression using a newly developed device. To evaluate the change in thoracic spinal cord blood flow by compression force and to clarify the association between blood flow recovery and motor deficiency after a spinal cord compression injury. Until now, no real-time measurement of spinal cord blood flow at the site of compression has been conducted. In addition, it has not been clearly determined whether blood flow recovery is related to motor function after a spinal cord injury. Our blood flow measurement system was a combination of a noncontact type laser Doppler system and a spinal cord compression device. The rat thoracic spinal cord was exposed at the 11th vertebra and spinal cord blood flow at the site of compression was continuously measured before, during, and after the compression. The functioning of the animal's hind-limbs was evaluated by the Basso, Beattie and Bresnahan scoring scale and the frequency of voluntary standing. Histologic changes such as permeability of blood-spinal cord barrier, microglia proliferation, and apoptotic cell death were examined in compressed spinal cord tissue. The spinal blood flow decreased on each increase in the compression force. After applying a 5-g weight, the blood flow decreased to compression), while no significant difference was observed between the 20-minute ischemia group and the sham group. In the 20-minute ischemia group, the rats whose spinal cord blood flow recovery was incomplete showed significant motor function loss compared with rats that completely recovered blood flow. Extensive breakdown of blood-spinal cord barrier integrity and the following microglia proliferation and apoptotic cell death were detected in the 40-minute complete ischemia group. Duration of ischemia/compression and blood flow recovery of the spinal cord are important factors in the recovery of motor function after a spinal cord injury.

Comparison of blood flow and cell function in ischemic skin flaps

International Nuclear Information System (INIS)

Bean, D.; Rees, R.S.; O'Leary, J.P.; Lynch, J.B.

1984-01-01

Cellular function and blood flow in acute, steroid-treated, and surgically delayed random skin flaps have been examined. In these studies, the period following flap elevation could be divided into early (0-2 hr), intermediate (4-6 hr), and late (12 hr) periods of ischemia, based on the cutaneous blood flow and cellular function measured by thallium-201 uptake. There was a close correlation between blood flow and cellular function during the early period of ischemia which became worse with time. Blood flow studies demonstrated a significant difference between the early and intermediate periods of ischemia which was abolished by surgical delay. Improvement in cellular function was accomplished by improved blood flow in the surgically delayed flaps, while steroid-treated flaps enhanced cellular metabolism by another mechanism. Cellular function approximated blood flow during the early and immediate period of ischemia. Steroids may augment cellular function without improving blood flow, while surgical delay improves cellular function by improving blood flow

In vivo evaluation of femoral blood flow measured with magnetic resonance

DEFF Research Database (Denmark)

Henriksen, O; Ståhlberg, F; Thomsen, C

1989-01-01

, corrected for the T2 decay of non-flowing blood was used to calculate the blood flow. As a reference, the blood flow in the femoral artery was measured simultaneously with an invasive indicator dilution technique. T2 of non-flowing blood was measured in vivo in popliteal veins during regional circulatory...... arrest. The mean T2 of non-flowing blood was found to be 105 +/- 31 ms. The femoral blood flow ranged between 0 and 643 ml/min measured with MRI and between 280 and 531 ml/min measured by the indicator dilution technique. There was thus poor agreement between the two methods. The results indicate......Quantitative measurements of blood flow based on magnetic resonance imaging (MRI) using conventional multiple spin echo sequences were evaluated in vivo in healthy young volunteers. Blood flow was measured using MRI in the femoral vein. The initial slope of the multiple spin echo decay curve...

Age- and gender-related hemorheological alterations in intestinal ischemia-reperfusion in the rat.

Science.gov (United States)

Mester, Anita; Magyar, Zsuzsanna; Molnar, Akos; Somogyi, Viktoria; Tanczos, Bence; Peto, Katalin; Nemeth, Norbert

2018-05-01

Intestinal ischemia-reperfusion (I/R) is a life-threatening clinical disorder. During I/R, the microrheological parameters of blood (red blood cell deformability and aggregation) worsen, which may contribute to microcirculatory deterioration. Age and gender also have a great influence on hemorheological parameters. We aimed to investigate the gender and age-related microrheological alterations during intestinal I/R. After the cannulation of the left femoral artery, median laparotomy was performed in Crl:WI rats under general anesthesia. In the young control animals there were no other interventions (female n = 7; male n = 7). In the young (female n = 7; male n = 7) and older I/R groups (female n = 6; male n = 6), the superior mesenteric artery was clipped for 30 min, and a 120-min reperfusion period was observed afterward. Blood samples were taken before and at the 30-min ischemia, in the 30th, 60th, and 120th min of the reperfusion. Hematological parameters, erythrocyte deformability, and aggregation were determined. Hematocrit increased significantly in the younger female I/R group. Red blood cell count was higher in male and older animals. In case of white blood cell count, male animals had higher values compared with females. Platelet count elevated in the younger male and older female I/R animals. Red blood cell deformability worsened, mainly in the male and older I/R groups. Enhanced erythrocyte aggregation was seen in all groups, being more expressed in the female I/R groups. Microrheological parameters show gender and age-related differences during intestinal I/R. These observations have importance in the planning and evaluation of experimental data. Copyright © 2018 Elsevier Inc. All rights reserved.

Abnormality in cerebellar blood flow in solo vertigo patients

Energy Technology Data Exchange (ETDEWEB)

Nagahori, Takeshi [Shakaihoken Takaoka Hospital, Toyama (Japan); Nishijima, Michiharu; Endo, Shunro; Takaku, Akira

1997-03-01

Little is known about the blood flow of the vertebrobasilar system as a cause of vertigo and dizziness. We used Xe-CT to study cerebellar blood flow in 53 patients who ranged in age from 35 to 85 years. The patients were divided into two groups. One of them was the vertigo group that comprised 28 patients with rotatory sensation, and the other, the non-vertigo group of 25 patients with a sensation other than rotation. At the stage of severe symptoms, there was decreased cerebellar blood flow in all patients of both, the vertigo and the non-vertigo groups, and a decrease in the bilateral cerebellar hemisphere was observed in five patients and in a unilateral hemisphere in three patients of the vertigo group. By comparison, in the non-vertigo group, unilateral decrease of cerebellar blood flow was observed in only one patient, and a bilateral decrease in five. At the stage of severe symptoms, the mean regional cerebellar blood flow was 40.5{+-}8.0 ml/100 g/min (n=16 sides) in the vertigo group and 45.3{+-}9.5 ml/100 g/min (n=12 sides) in the non-vertigo group. At the stage of moderate symptoms, blood flow image was normal in four of 14 vertigo patients and in seven of 12 non-vertigo patients. The mean regional blood flow was 47.8{+-}8.6 ml/100 g/min (n=28 sides) in the vertigo group and 47.1{+-}5.1 ml/100 g/min (n=24 sides) in the non-vertigo group. At the asymptomatic stage, a high proportion of normal blood flow images (nine of 16 vertigo patients and 10 of 10 non-vertigo patients) was observed. The mean regional cerebellar blood flow was 51.6{+-}10.7 ml/100 g/min (n=32 sides) in the vertigo group and 52.8{+-}8.5 ml/100 g/min (n=20 sides) in the non-vertigo group. This study demonstrates that a unilateral or bilateral decrease in blood flow of the vertebrobasilar system may cause vertigo and dizziness. It also shows that Xe-CT of the cerebellum may be a valuable examination modality for the diagnosis and treatment of vertigo and dizziness. (author)

Abnormality in cerebellar blood flow in solo vertigo patients

International Nuclear Information System (INIS)

Nagahori, Takeshi; Nishijima, Michiharu; Endo, Shunro; Takaku, Akira

1997-01-01

Little is known about the blood flow of the vertebrobasilar system as a cause of vertigo and dizziness. We used Xe-CT to study cerebellar blood flow in 53 patients who ranged in age from 35 to 85 years. The patients were divided into two groups. One of them was the vertigo group that comprised 28 patients with rotatory sensation, and the other, the non-vertigo group of 25 patients with a sensation other than rotation. At the stage of severe symptoms, there was decreased cerebellar blood flow in all patients of both, the vertigo and the non-vertigo groups, and a decrease in the bilateral cerebellar hemisphere was observed in five patients and in a unilateral hemisphere in three patients of the vertigo group. By comparison, in the non-vertigo group, unilateral decrease of cerebellar blood flow was observed in only one patient, and a bilateral decrease in five. At the stage of severe symptoms, the mean regional cerebellar blood flow was 40.5±8.0 ml/100 g/min (n=16 sides) in the vertigo group and 45.3±9.5 ml/100 g/min (n=12 sides) in the non-vertigo group. At the stage of moderate symptoms, blood flow image was normal in four of 14 vertigo patients and in seven of 12 non-vertigo patients. The mean regional blood flow was 47.8±8.6 ml/100 g/min (n=28 sides) in the vertigo group and 47.1±5.1 ml/100 g/min (n=24 sides) in the non-vertigo group. At the asymptomatic stage, a high proportion of normal blood flow images (nine of 16 vertigo patients and 10 of 10 non-vertigo patients) was observed. The mean regional cerebellar blood flow was 51.6±10.7 ml/100 g/min (n=32 sides) in the vertigo group and 52.8±8.5 ml/100 g/min (n=20 sides) in the non-vertigo group. This study demonstrates that a unilateral or bilateral decrease in blood flow of the vertebrobasilar system may cause vertigo and dizziness. It also shows that Xe-CT of the cerebellum may be a valuable examination modality for the diagnosis and treatment of vertigo and dizziness. (author)

Aging, regional cerebral blood flow, and neuropsychological functioning

International Nuclear Information System (INIS)

MacInnes, W.D.; Golden, C.J.; Gillen, R.W.; Sawicki, R.F.; Quaife, M.; Uhl, H.S.; Greenhouse, A.J.

1984-01-01

Previous studies found changes in regional cerebral blood flow (rCBF) patterns related to both age and various cognitive tasks. However, no study has yet demonstrated a relationship between rCBF and performance on the Luria-Nebraska Neuropsychological Battery (LNNB) in an elderly group. Seventy-nine elderly volunteers (56-88 years old), both healthy and demented, underwent the 133 xenon inhalation rCBF procedure and were given the LNNB. The decrements in the gray-matter blood flow paralleled decrements in performance on the LNNB. Using partial correlations, a significant proportion of shared variance was observed between gray-matter blood flow and the LNNB scales. However, there was much less of a relationship between white-matter blood flow and performance on the LNNB. This study suggests that even within a restricted age sample rCBF is related in a global way to neuropsychological functioning

Myocardial blood flow during induced aortic hypertension in dogs

International Nuclear Information System (INIS)

Thai, B.N.; Levesque, M.J.; Nerem, R.M.

1986-01-01

Myocardial blood flow was measured in anesthetized dogs during control conditions and under conditions where the aortic pressure was increased due to aortic constriction or during infusion. Blood flow was measured using the radioactive microsphere technique. Radioactive microspheres (15 m Ce-141, Sr-85, and Sc-46) were injected under control, aortic constriction and arterenol infusion in four dogs and under control conditions in two others. All microsphere injections were performed under stabilized conditions. It was found that coronary blood flow rose by 80% during aortic constriction and by 158% during arterenol infusion (P < 0.05). This increase in blood flow was not uniform throughout the heart, and higher increases were observed in the middle and apex regions of the left ventricle. Furthermore, under hypertension the increase in blood flow in LAD (left anterior descending) perfused territories was slightly higher than that in CFX (left circumflex) perfused territories

Low cerebral blood flow in hypotensive perinatal distress

DEFF Research Database (Denmark)

Lou, H C; Lassen, N A; Friis-Hansen, B

1977-01-01

was used for the cerebral blood flow measurements. The study confirmed that perinatal distress may be associated with low arterial blood pressure, and it was shown that cerebral blood flow is very low, 20 ml/100 g/min or less, in hypotensive perinatal distress. It is concluded that cerebral ischaemia plays...... a crucial role in the development of perinatal hypoxic brain injury....

Isoflurane anesthesia initiated at the onset of reperfusion attenuates oxidative and hypoxic-ischemic brain injury.

Directory of Open Access Journals (Sweden)

Sergey A Sosunov

Full Text Available This study demonstrates that in mice subjected to hypoxia-ischemia (HI brain injury isoflurane anesthesia initiated upon reperfusion limits a release of mitochondrial oxidative radicals by inhibiting a recovery of complex-I dependent mitochondrial respiration. This significantly attenuates an oxidative stress and reduces the extent of HI brain injury. Neonatal mice were subjected to HI, and at the initiation of reperfusion were exposed to isoflurane with or without mechanical ventilation. At the end of HI and isoflurane exposure cerebral mitochondrial respiration, H2O2 emission rates were measured followed by an assessment of cerebral oxidative damage and infarct volumes. At 8 weeks after HI navigational memory and brain atrophy were assessed. In vitro, direct effect of isoflurane on mitochondrial H2O2 emission was compared to that of complex-I inhibitor, rotenone. Compared to controls, 15 minutes of isoflurane anesthesia inhibited recovery of the compex I-dependent mitochondrial respiration and decreased H2O2 production in mitochondria supported with succinate. This was associated with reduced oxidative brain injury, superior navigational memory and decreased cerebral atrophy compared to the vehicle-treated HI-mice. Extended isoflurane anesthesia was associated with sluggish recovery of cerebral blood flow (CBF and the neuroprotection was lost. However, when isoflurane anesthesia was supported with mechanical ventilation the CBF recovery improved, the event associated with further reduction of infarct volume compared to HI-mice exposed to isoflurane without respiratory support. Thus, in neonatal mice brief isoflurane anesthesia initiated at the onset of reperfusion limits mitochondrial release of oxidative radicals and attenuates an oxidative stress. This novel mechanism contributes to neuroprotective action of isoflurane. The use of mechanical ventilation during isoflurane anesthesia counterbalances negative effect of isoflurane anesthesia on

Do indices of coronary conductance after reperfusion reflect the extent of salvaged myocardium?

Science.gov (United States)

Shibata, Takahiro; Watanabe, Hisashi; Tsurusaki, Tetsushi; Minai, Kousuke; Ogawa, Takayuki; Iwano, Keiji; Tamura, Tetsutarou; Yoshida, Satoshi; Mutou, Makoto; Imai, Kamon; Horie, Toshinobu; Mochizuki, Seibu

2004-05-01

Existing indices of coronary conductance (hyperemic flow-versus-pressure slope index, FPSI, and zero flow pressure, Pzf) have been developed as measures of microcoronary resistance. These indices, however, refer to cases of normal hearts, and there are no reports studying these indices following acute myocardial infarction. In this study, we investigated whether FPSI and Pzf truly measure the extent of myocardial salvage after successful reperfusion therapy. We also developed a new index of zero pressure flow, Fzp. Nineteen patients who underwent successful reperfusion therapy to the proximal portion of the left anterior descending artery (LAD) were studied. After successful reperfusion therapy, a Doppler wire was placed into the LAD. Aortic pressure was recorded in real time. Results from the aortic pressure and flow meter were combined to produce FPSI, Pzf, and Fzp. All cases underwent a resting thallium (Tl) and BMIPP scintigram within five days of successful reperfusion therapy. Infarcted myocardium was estimated using a severity score calculated from the Tl scintigraphy (TlSS), and the BMIPP (BMIPPSS) was estimated using a severity score. Patients with a TlSS/BMIPPSS ratio of less than 0.4 were assigned to the successful salvage group (group S), while the others were assigned to the failed salvage group (group F). FPSI of group F was 1.91 +/- 0.26 m/sec and of group S was 0.92 +/- 0.43 m/sec (P < 0.01). Pzf of group F was 51 +/- 3 mmHg and of group S was 51 +/- 5 mmHg (NS). Fzp of group F was -98 +/- 16 cm/sec and of group S was -46 +/- 4 cm/sec (P < 0.05). FPSI and the new index of Fzp were useful in estimating the extent of myocardial salvage. Our results suggest that the Pzf index could not differentiate between the two groups.

Nitric oxide and prostaglandins influence local skeletal muscle blood flow during exercise in humans: coupling between local substrate uptake and blood flow

DEFF Research Database (Denmark)

Kalliokoski, Kari K; Langberg, Henning; Ryberg, Ann Kathrine

2006-01-01

-legged dynamic knee-extension exercise. Local blockade was produced by infusing nitro-L-arginine methyl ester and indomethacin directly in the muscle via a microdialysis catheter. Blood flow and glucose uptake were measured in the region of blockade and in two additional regions of vastus lateralis muscle 1......Synergic action of nitric oxide (NO) and prostaglandins (PG) in the regulation of muscle blood flow during exercise has been demonstrated. In the present study, we investigated whether these vasodilators also regulate local blood flow, flow heterogeneity, and glucose uptake within the exercising...... skeletal muscle. Skeletal muscle blood flow was measured in seven healthy young men using near-infrared spectroscopy and indocyanine green and muscle glucose uptake using positron emission tomography and 2-fluoro-2-deoxy-D-[(18)F]glucose without and with local blockade of NO and PG at rest and during one...

Regional cerebral blood flow measurement in brain tumors

International Nuclear Information System (INIS)

Izunaga, Hiroshi; Hirota, Yoshihisa; Takahashi, Mutsumasa; Fuwa, Isao; Kodama, Takafumi; Matsukado, Yasuhiko

1986-01-01

The regional cerebral blood flow (CBF) was determined on seventeen patients with brain tumors. Ring type single photon emission CT (SPECT) was used following intravenous injection of 133 Xe. Case materials included eleven meningiomas and six malignant gliomas. Evaluation was performed with emphasis on the following points; 1. Correlation of the flow data within tumors to the angiographic tumor stains, 2. Influence of tumors on the cerebral blood flow of the normal brain tissue, 3. Correlation between degree of peripheral edema and the flow data of the affected hemispheres. There was significant correlation between flow data within tumors and angiographic tumor stains in meningiomas. Influence of tumors on cerebral blood flow of the normal tissue was greater in meningiomas than in gliomas. There was negative correlation between the degree of peripheral edema and the flow data of the affected hemisphere. It has been concluded that the measurement of CBF in brain tumors is a valuable method in evaluation of brain tumors. (author)

Regional cerebral blood flow measurement in brain tumors

Energy Technology Data Exchange (ETDEWEB)

Izunaga, Hiroshi; Hirota, Yoshihisa; Takahashi, Mutsumasa; Fuwa, Isao; Kodama, Takafumi; Matsukado, Yasuhiko

1986-10-01

The regional cerebral blood flow (CBF) was determined on seventeen patients with brain tumors. Ring type single photon emission CT (SPECT) was used following intravenous injection of /sup 133/Xe. Case materials included eleven meningiomas and six malignant gliomas. Evaluation was performed with emphasis on the following points; 1. Correlation of the flow data within tumors to the angiographic tumor stains, 2. Influence of tumors on the cerebral blood flow of the normal brain tissue, 3. Correlation between degree of peripheral edema and the flow data of the affected hemispheres. There was significant correlation between flow data within tumors and angiographic tumor stains in meningiomas. Influence of tumors on cerebral blood flow of the normal tissue was greater in meningiomas than in gliomas. There was negative correlation between the degree of peripheral edema and the flow data of the affected hemisphere. It has been concluded that the measurement of CBF in brain tumors is a valuable method in evaluation of brain tumors.

Allowable warm ischemic time and morphological and biochemical changes in uterine ischemia/reperfusion injury in cynomolgus macaque: a basic study for uterus transplantation.

Science.gov (United States)

Kisu, Iori; Umene, Kiyoko; Adachi, Masataka; Emoto, Katsura; Nogami, Yuya; Banno, Kouji; Itagaki, Iori; Kawamoto, Ikuo; Nakagawa, Takahiro; Narita, Hayato; Yoshida, Atsushi; Tsuchiya, Hideaki; Ogasawara, Kazumasa; Aoki, Daisuke

2017-10-01

How long is the allowable warm ischemic time of the uterus and what morphological and biochemical changes are caused by uterine ischemia/reperfusion injury in cynomolgus macaques? Warm ischemia in the uterus of cynomolgus macaques is tolerated for up to 4 h and reperfusion after uterine ischemia caused no further morphological and biochemical changes. Uterus transplantation is a potential option for women with uterine factor infertility. The allowable warm ischemic time and ischemia/reperfusion injury of the uterus in humans and non-human primates is unknown. This experimental study included 18 female cynomolgus macaques with periodic menstruation. Animals were divided into six groups of three monkeys each: a control group and groups with uterine ischemia for 0.5, 1, 2, 4 and 8 h. Biopsies of uterine tissues were performed before blood flow blockage, after each blockage time, and after reperfusion for 3 h. Blood sampling was performed after each blockage time, and after reperfusion for 5, 15 and 30 min for measurement of biochemical data. Resumption of menstruation was monitored after the surgical procedure. Morphological, physiological and biochemical changes after ischemia and reperfusion were evaluated. Mild muscle degeneration and zonal degeneration were observed in all animals subjected to warm ischemia for 4 or 8 h, but there were no marked differences in the appearance of specimens immediately after ischemia and after reperfusion for 3 h in animals subjected to 4 or 8 h of warm ischemia. There were no significant changes in any biochemical parameters at any time point in each group. Periodical menstruation resumed in all animals with warm ischemia up to 4 h, but did not recover in animals with warm ischemia for 8 h with atrophic uteri. Warm ischemia in actual transplantation was not exactly mimicked in this study because uteri were not perfused, cooled, transplanted or reanastomosed with vessels. Results in non-human primates cannot always be extrapolated to

Local viscosity distribution in bifurcating microfluidic blood flows

Science.gov (United States)

Kaliviotis, E.; Sherwood, J. M.; Balabani, S.

2018-03-01

The red blood cell (RBC) aggregation phenomenon is majorly responsible for the non-Newtonian nature of blood, influencing the blood flow characteristics in the microvasculature. Of considerable interest is the behaviour of the fluid at the bifurcating regions. In vitro experiments, using microchannels, have shown that RBC aggregation, at certain flow conditions, affects the bluntness and skewness of the velocity profile, the local RBC concentration, and the cell-depleted layer at the channel walls. In addition, the developed RBC aggregates appear unevenly distributed in the outlets of these channels depending on their spatial distribution in the feeding branch, and on the flow conditions in the outlet branches. In the present work, constitutive equations of blood viscosity, from earlier work of the authors, are applied to flows in a T-type bifurcating microchannel to examine the local viscosity characteristics. Viscosity maps are derived for various flow distributions in the outlet branches of the channel, and the location of maximum viscosity magnitude is obtained. The viscosity does not appear significantly elevated in the branches of lower flow rate as would be expected on the basis of the low shear therein, and the maximum magnitude appears in the vicinity of the junction, and towards the side of the outlet branch with the higher flow rate. The study demonstrates that in the branches of lower flow rate, the local viscosity is also low, helping us to explain why the effects of physiological red blood cell aggregation have no adverse effects in terms of in vivo vascular resistance.

Determination of myocardial blood flow by videodensitometry

International Nuclear Information System (INIS)

Erikson, U.; Helmius, G.; Hennig, K.; Johansson, L.; Enghoff, E.; Ruhn, G.

1981-01-01

Videodensitometry has hitherto been used as a tool for measuring regional blood flow in the kidneys and lungs by means of the well known Stewart Hamilton curve (wash-out) technique. This preliminary report suggests the possibility of using this method to measure coronary blood flow. Thirty-six patients, 29 of whom had angina pectoris, underwent videodensitometry in connection with coronary angiography. (orig.) [de

Chronic Co-Administration of Sepiapterin and L-Citrulline Ameliorates Diabetic Cardiomyopathy and Myocardial Ischemia/Reperfusion Injury in Obese Type 2 Diabetic Mice.

Science.gov (United States)

Baumgardt, Shelley L; Paterson, Mark; Leucker, Thorsten M; Fang, Juan; Zhang, David X; Bosnjak, Zeljko J; Warltier, David C; Kersten, Judy R; Ge, Zhi-Dong

2016-01-01

Diabetic heart disease is associated with tetrahydrobiopterin oxidation and high arginase activity, leading to endothelial nitric oxide synthase dysfunction. Sepiapterin (SEP) is a tetrahydrobiopterin precursor, and L-citrulline (L-Cit) is converted to endothelial nitric oxide synthase substrate, L-arginine. Whether SEP and L-Cit are effective at reducing diabetic heart disease is not known. The present study examined the effects of SEP and L-Cit on diabetic cardiomyopathy and ischemia/reperfusion injury in obese type 2 diabetic mice. Db/db and C57BLKS/J mice at 6 to 8 weeks of age received vehicle, SEP, or L-Cit orally alone or in combination for 8 weeks. Cardiac function was evaluated with echocardiography. Db/db mice displayed hyperglycemia, obesity, and normal blood pressure and cardiac function compared with C57BLKS/J mice at 6 to 8 weeks of age. After vehicle treatment for 8 weeks, db/db mice had reduced ejection fraction, mitral E/A ratio, endothelium-dependent relaxation of coronary arteries, tetrahydrobiopterin concentrations, ratio of endothelial nitric oxide synthase dimers/monomers, and nitric oxide levels compared with vehicle-treated C57BLKS/J mice. These detrimental effects of diabetes mellitus were abrogated by co-administration of SEP and L-Cit. Myocardial infarct size was increased, and coronary flow rate and ± dP/dt were decreased during reperfusion in vehicle-treated db/db mice subjected to ischemia/reperfusion injury compared with control mice. Co-administration of SEP and L-Cit decreased infarct size and improved coronary flow rate and cardiac function in both C57BLKS/J and db/db mice. Co-administration of SEP and L-Cit limits diabetic cardiomyopathy and ischemia/reperfusion injury in db/db mice through a tetrahydrobiopterin/endothelial nitric oxide synthase/nitric oxide pathway. © 2016 American Heart Association, Inc.

Breath pentane as a potential biomarker for survival in hepatic ischemia and reperfusion injury--a pilot study.

Directory of Open Access Journals (Sweden)

Changsong Wang

Full Text Available BACKGROUND: Exhaled pentane, which is produced as a consequence of reactive oxygen species-mediated lipid peroxidation, is a marker of oxidative stress. Propofol is widely used as a hypnotic agent in intensive care units and the operating room. Moreover, this agent has been reported to inhibit lipid peroxidation by directly scavenging reactive oxygen species. In this study, using a porcine liver ischemia-reperfusion injury model, we have evaluated the hypothesis that high concentrations of breath pentane are related to adverse outcome and that propofol could reduce breath pentane and improve liver injury and outcome in swine in this situation. METHODOLOGY/PRINCIPAL FINDINGS: Twenty male swine were assigned to two groups: propofol (n = 10 and chloral hydrate groups (n = 10. Hepatic ischemia was induced by occluding the portal inflow vessels. Ischemia lasted for 30 min, followed by reperfusion for 360 min. Exhaled and blood pentane concentrations in the chloral hydrate group markedly increased 1 min after reperfusion and then decreased to baseline. Breath and blood pentane concentrations in the propofol group increased 1 min after reperfusion but were significantly lower than in the chloral hydrate group. A negative correlation was found between breath pentane levels and survival in the chloral hydrate group. The median overall survival was 251 min after reperfusion (range 150-360 min in the chloral hydrate group. All of the swine were alive in the propofol group. CONCLUSIONS: Monitoring of exhaled pentane may be useful for evaluating the severity of hepatic ischemia-reperfusion injury and aid in predicting the outcome; propofol may improve the outcome in this situation.

Determination of splenic blood flow by inhalation of radioactive rare gases

Energy Technology Data Exchange (ETDEWEB)

Huchzermeyer, H; Schmitz-Feuerhake, I; Reblin, T [Medizinische Hochschule Hannover (Germany, F.R.). Abt. fuer Nuklearmedizin und Spezielle Biophysik; Medizinische Hochschule Hannover (Germany, F.R.). Abt. fuer Gastroenterologie)

1977-10-01

We have evaluated the /sup 133/Xenon inhalation method for the determination of splenic blood flow. In twenty-two healthy persons the blood flow was on average 109 +- 4 ml/100 g x min, which is equivalent to a total blood flow of about 170 ml/min. In patients with chronic fatty liver hepatitis specific blood flow was reduced (81 +- 10 ml/100 g x min) as it was in patients with cirrhotic liver without splenomegaly (75 +- 2 ml/100 g x min.). With increasing weight of the spleen, the total blood flow rises, although specific blood flow is low. Our results obtained by the /sup 133/Xenon inhalation method are similar to results obtained by others using intraarterial injection of tracer gas. The advantages of the inhalation method as a non-traumatic method are: 1) the stress for the patient is very small; 2) blood flow measurements can be repeated within short periods of time. We consider for the present the /sup 133/Xenon inhalation method to be the method of choice for the determination of the splenic blood flow.

Effect of loading-dose ticagrelor on coronary blood flow, left ventricular remodeling and myocardial enzyme spectrum in patients with acute myocardial infarction after interventional therapy

Directory of Open Access Journals (Sweden)

Xiao-Rui Xie

2016-12-01

Full Text Available Objective: To study the effect of loading-dose ticagrelor on coronary blood flow, left ventricular remodeling and myocardial enzyme spectrum in patients with acute myocardial infarction after interventional therapy. Methods: A total of 86 patients with acute myocardial infarction who received emergency PCI in our hospital between May 2013 and May 2016 were selected and randomly divided into two groups, ticagrelor group received perioperative ticagrelor therapy and clopidogrel group received perioperative clopidogrel therapy. After PCI, coronary blood flow reperfusion was evaluated, serum myocardial remodeling indexes and myocardial enzymes were determined, and cardiac color Doppler ultrasonography was conducted to determine the cardiac function indexes. Results: TIMI grading and TMPG grading of ticagrelor group after PCI were significantly higher than those of clopidogrel group; serum MMP9, BNP, CITP, PICP, PIIINP, CK, CK-MB, cTnI and cTnT content of ticagrelor group 24h after operation were significantly lower than those of clopidogrel group; LVEDD, LVSED and LVMI of ticagrelor group 2 weeks after operation were significantly lower than those of clopidogrel group while LVEF was significantly higher than that of clopidogrel group. Conclusion: Peri-PCI loading-dose ticagrelor can improve coronary blood perfusion and reduce ventricular remodeling and myocardial injury in patients with acute myocardial infarction.

Measurement of regional hepatic blood flow by scintiphotosplenoportography

Energy Technology Data Exchange (ETDEWEB)

Kashiwagi, T; Kimura, K; Kamada, T; Abe, H [Osaka Univ. (Japan). Dept. of Radiology and Nuclear Medicine

1978-08-01

A new technique for estimating regional hepatic blood flow using the inert gas washout technique and scintillation camera following injection of /sup 133/Xe into the spleen is presented. This technique is easily, rapidly and repeatedly performed and permits the measurement of nutrient hepatic tissue blood flow. Measurement of regional hepatic blood flow in right and/or left lobes was performed in 28 patients. In all but one patient the right lobar flow value was equal to or greater than the left one. The right lobar flow was 86.20 +- 12.83 ml/100 gm/min in 3 patients without liver disease, 75.12 +- 14.54 ml/100 gm/min in 12 with chronic hepatitis and 51.24 +- 17.13 ml/100 gm/min in 11 with liver cirrhosis. This result suggests that hepatic tissue blood flow is significantly decreased in patients with liver cirrhosis. Scintillation camera images of initial xenon distribution in combination with monitor of washout curves over the liver also provide more information on the presence of extra- and intrahepatic shunts. Therefore, this technique appears to be clinically useful in evaluation of hemodynamic phenomena associated with liver diseases.

Uteroplacental blood flow during alkalosis in the sheep

International Nuclear Information System (INIS)

Buss, D.D.; Bisgard, G.E.; Rawlings, C.A.; Rankin, J.H.G.

1975-01-01

Uteroplacental blood flow was measured by the radioactive-microsphere technique in eight near-term pregnant ewes during a normal control period and during maternal metabolic alkalosis. All measurements were made on awake, unanesthetized animals. Alkalosis, defined for this study as an arterial pH of 7.60 or greater, was produced by the oral administration of sodium bicarbonate, 3 g/kg body wt. The rise in pH thus produced was unaccompanied by significant changes in systemic arterial blood pressure and cardiac output, while maternal arterial P/sub CO 2 / rose slightly from control levels. Cotyledonary blood flow declined from a control value of 1.177 ml/min to 1.025 ml/min during alkalosis. This decline of 13 percent in cotyledonary blood flow is significant (P less than 0.02). Blood flow to the remaining uterine tissue, or noncotyledonary uterus, did not change with alkalosis, being maintained at approximately 195 ml/min. It is concluded that maternal alkalosis, unaccompanied by major changes in P /sub CO 2 / and systemic arterial pressure, causes a small increase in the resistance of the uteroplacental circulation

The blood flow changes associated with idiopathic and secondary intracranial hypertension

International Nuclear Information System (INIS)

Bateman, G.

2002-01-01

Full text: The radiological diagnosis of idiopathic intracranial hypertension (IIH) is one of exclusion and as the MR venogram is prone to flow artefacts, the diagnosis of secondary intracranial hypertension (SIH) can also be problematic. The purpose of this paper is to define the blood flow characteristics, which are useful in the diagnosis of these conditions. Twelve patients with clinical findings suggestive of IIH and 12 control subjects were investigated with MR venography and MR flow quantification studies of the cerebral arteries and veins. Total cerebral blood flow, superior sagittal sinus (SSS) and straight sinus (ST) blood flows were measured. MR venography confirmed 7 of the 12 patients had venous outflow obstruction and thus SIH. The remaining 5 patients had IIH. The control patients mean total blood flow was 855 ml/min, the SSS flow was 400ml/min and the ST flow 117 ml/min. The total blood flow in the IIH patients was 46% higher (P = 0.0002) and the ST blood flow 38% higher (P = 0.05) than the control group, the SSS flow was 17% higher but this failed to reach significance. In SIH the SSS flow was reduced by 25% (P = 0.003) compared with the control group, the total and ST blood flow were not significantly altered. In IIH there is hyperaemia and the SSS appears limited in its ability to increase flow, therefore venous collaterals carry a greater load. In SIH, selective obstruction of the SSS reduces flow in this vessel but total blood flow is normal indicating there is also increased flow in collateral veins. Presumably the limited ability of the SSS to drain blood away from the brain in each condition raises venous sinus pressure and alters CSF resorption giving raised CSF pressure. Copyright (2002) Blackwell Science Pty Ltd

Trial on MR portal blood flow measurement with phase contrast technique

International Nuclear Information System (INIS)

Tsunoda, Masatoshi; Kimoto, Shin; Togami, Izumi

1991-01-01

Portal blood flow measurement is considered to be important for the analysis of hemodynamics in various liver diseases. The Doppler ultrasound method has been used extensively during the past several years for measuring portal blood flow, as a non-invasive method. However, the Doppler ultrasound technique do not allow the portal blood flow to be measured in cases of obesity, with much intestinal gas, and so on. In this study, we attempted to measure the blood flow in the main trunk of portal vein as an application of MR phase contrast technique to the abdominal region. In the flow phantom study, the flow volumes and the velocities measured by phase contrast technique showed a close correlation with those measured by electromagnetic flowmeter. In the clinical study with 10 healthy volunteers, various values of portal blood flow were obtained. Mean portal blood flow could be measured within the measuring time (about 8 minutes) under natural breathing conditions. Phase contrast technique is considered to be useful for the non-invasive measurement of portal blood flow. (author)

Cutaneous blood flow rate in areas with and without arteriovenous anastomoses during exercise

DEFF Research Database (Denmark)

Midttun, M.; Sejrsen, Per

1998-01-01

Arteriovenous anastomoses, capillaries, cutaneous bllod flow rate, exercise, finger blood flow, skin blood flow......Arteriovenous anastomoses, capillaries, cutaneous bllod flow rate, exercise, finger blood flow, skin blood flow...

Therapeutic Effect of Low Doses of Acenocoumarol in the Course of Ischemia/Reperfusion-Induced Acute Pancreatitis in Rats

Directory of Open Access Journals (Sweden)

Zygmunt Warzecha

2017-04-01

Full Text Available Intravascular activation of coagulation is observed in acute pancreatitis and is related to the severity of this inflammation. The aim of our study was to evaluate the impact of acenocoumarol therapy on the course of acute pancreatitis induced in male rats by pancreatic ischemia followed by reperfusion. Acenocoumarol at a dose of 50, 100, or 150 µg/kg/dose was administered intragastrically once a day, starting the first dose 24 h after the initiation of pancreatic reperfusion. Results: Histological examination showed that treatment with acenocoumarol reduces pancreatic edema, necrosis, and hemorrhages in rats with pancreatitis. Moreover, the administration of acenocoumarol decreased pancreatic inflammatory infiltration and vacuolization of pancreatic acinar cells. These findings were accompanied with a reduction in the serum activity of lipase and amylase, concentration of interleukin-1β, and plasma d-Dimer concentration. Moreover, the administration of acenocoumarol improved pancreatic blood flow and pancreatic DNA synthesis. Acenocoumarol given at a dose of 150 µg/kg/dose was the most effective in the treatment of early phase acute pancreatitis. However later, acenocoumarol given at the highest dose failed to exhibit any therapeutic effect; whereas lower doses of acenocoumarol were still effective in the treatment of acute pancreatitis. Conclusion: Treatment with acenocoumarol accelerates the recovery of ischemia/reperfusion-induced acute pancreatitis in rats.

Comparative assessment of 18F-fluorodeoxyglucose PET and 99mTc-tetrofosmin SPECT for the prediction of functional recovery in patients with reperfused acute myocardial infarction

International Nuclear Information System (INIS)

Shirasaki, Haruhisa; Nakano, Akira; Uzui, Hiroyasu; Ueda, Takanori; Lee, Jong-Dae; Yonekura, Yoshiharu; Okazawa, Hidehiko

2006-01-01

Purpose: Although preserved glucose metabolism is considered to be a marker of myocardial viability in the chronic stage, it has not been fully elucidated whether this is also true with regard to reperfused acute myocardial infarction (AMI). The aim of this study was to compare the diagnostic performance of 99m Tc-tetrofosmin SPECT and 18 F-fluorodeoxyglucose (FDG) PET for the prediction of functional recovery in reperfused AMI.Methods: The study population comprised 28 patients. Both tetrofosmin SPECT and FDG PET were performed in all 28 patients at ca. 2 weeks and in 23 at 6 months. The tetrofosmin and FDG findings in infarct-related segments were compared with the regional wall motion score assessed by left ventriculography over 6 months to determine the predictive value for functional recovery. Of 120 infarct-related segments, 83 had preserved flow (tetrofosmin uptake ≥50%) and 81 had preserved glucose metabolism (FDG uptake ≥40%). The sensitivity and specificity of tetrofosmin SPECT for the prediction of functional recovery tended to be superior to those of FDG PET (90.0% and 72.5% vs 85.0% and 67.5%, respectively). Thirteen segments with preserved flow and decreased glucose metabolism demonstrated marked recovery of contractile function from 2.5±1.0 to 1.4±1.4 (p<0.01), with restoration of glucose metabolism at 6 months. In contrast, 11 segments with decreased flow and preserved glucose metabolism demonstrated incomplete functional improvement from 3.0±0.8 to 2.2±1.2. In the subacute phase, preserved myocardial blood flow is more reliable than glucose metabolism in predicting functional recovery in reperfused myocardium. (orig.)

Effect of fluocinolone acetonide cream on human skin blood flow

International Nuclear Information System (INIS)

Chimoskey, J.E.; Holloway, A. Jr.; Flanagan, W.J.

1975-01-01

Blood flow rate was measured in the forearm skin of human subjects exposed to ultraviolet irradiation. Blood flow was determined by the 133 Xe disappearance technique 18 hr after ultraviolet (UV) irradiation with a Westinghouse RS sunlamp held 10 inches from the skin for 10 min. Ultraviolet irradiation caused skin blood flow to increase. Application of fluocinolone acetonide cream, 0.025 percent, 4 times in the 16 hr following UV irradiation had no effect on either control skin blood flow or the UV-induced hyperemia

Distribution of carbon flux within fatty acid utilization during myocardial ischemia and reperfusion

International Nuclear Information System (INIS)

Nellis, S.H.; Liedtke, A.J.; Renstrom, B.

1991-01-01

Twenty-nine intact, working pig hearts were extracorporeally perfused and divided into two study groups (16 Aerobic and 13 Ischemic/Reflow hearts). Step function, equilibrium labeling with [14C]palmitate was used to develop uptake and washout curves of radioactive fatty acid products contained in coronary effluent during either aerobic perfusion or reperfusion after ischemia (60% reduction in left anterior descending coronary flow for 30 minutes). Left anterior descending control flows were slightly overperfused in Aerobic hearts (18% higher than in Ischemic/Reflow hearts); otherwise, circumflex and right coronary flows, left ventricular pressure, and serum fatty acids and blood sugar levels were comparable between groups. As expected in Ischemic/Reflow hearts, recovery of regional systolic shortening and myocardial oxygen consumption in reperfusion was only modestly impaired (-20% and -19%, respectively, not significant and p less than 0.011 compared with preischemic values, not significant from Aerobic hearts). The only significant metabolized product to be released from labeled fatty acid utilization in either group was 14CO2. A smaller fatty acid pool also was measured and accounted for by that contained in the coronary intravascular volume. The authors could determine no significant back diffusion of fatty acids from myocardium in either perfusion condition. Uptake time constants of the early phase of 14CO2 production also were virtually identical in both groups (19.9 ± 3.2 versus 16.7 ± 3.2 minutes in Aerobic and Ischemic/Reflow hearts, respectively) and strongly correlated with hemodynamics as described by heart rate. In washout studies, tissue radioactivity in the aqueous soluble and fatty acid pools declined in both study groups, and counts in complex lipids and cholesterol/cholesteryl esters remained steady, whereas those in triacylglycerols varied

Glucagon-like peptide-2 increases mesenteric blood flow in humans

DEFF Research Database (Denmark)

Bremholm, Lasse; Hornum, Mads; Henriksen, Birthe Merete

2008-01-01

a significant association between IV and SC administration of synthetic GLP-2 and changes in mesenteric blood flow. An exponential dose-response relationship was observed after IV infusion. The meal-induced changes in mesenteric blood flow over time were similar to those obtained by SC GLP-2. Thus, our results......OBJECTIVE: Mesenteric blood flow is believed to be influenced by digestion and absorption of ingested macronutrients. We hypothesized that the intestinotrophic hormone, GLP-2 (glucagons-like peptide 2), may be involved in the regulation of mesenteric blood flow. Changes in mesenteric blood flow...... were measured by Doppler ultrasound scanning of the superior mesenteric artery (SMA). The aim of the study was to demonstrate the influence of GLP-2 on this flow, expressed as changes in resistance index (RI). MATERIAL AND METHODS: A homogeneous group of 10 fasting healthy volunteers completed a 2-day...

A feasability study of color flow doppler vectorization for automated blood flow monitoring.

Science.gov (United States)

Schorer, R; Badoual, A; Bastide, B; Vandebrouck, A; Licker, M; Sage, D

2017-12-01

An ongoing issue in vascular medicine is the measure of the blood flow. Catheterization remains the gold standard measurement method, although non-invasive techniques are an area of intense research. We hereby present a computational method for real-time measurement of the blood flow from color flow Doppler data, with a focus on simplicity and monitoring instead of diagnostics. We then analyze the performance of a proof-of-principle software implementation. We imagined a geometrical model geared towards blood flow computation from a color flow Doppler signal, and we developed a software implementation requiring only a standard diagnostic ultrasound device. Detection performance was evaluated by computing flow and its determinants (flow speed, vessel area, and ultrasound beam angle of incidence) on purposely designed synthetic and phantom-based arterial flow simulations. Flow was appropriately detected in all cases. Errors on synthetic images ranged from nonexistent to substantial depending on experimental conditions. Mean errors on measurements from our phantom flow simulation ranged from 1.2 to 40.2% for angle estimation, and from 3.2 to 25.3% for real-time flow estimation. This study is a proof of concept showing that accurate measurement can be done from automated color flow Doppler signal extraction, providing the industry the opportunity for further optimization using raw ultrasound data.

Tumor blood flow and pH changes after glucose administration

International Nuclear Information System (INIS)

Thistlethwaite, A.J.; Tupchong, L.; Leeper, D.B.

1987-01-01

The authors used a laser doppler technique to correlate blood flow changes with pH changes in human tumors after glucose ingestion. Three PTs with large superficial tumors ingested 100 gm glucose. A 21g needle pH electrode (Micro-electrodes, Inc.) and a 21g ''Laserflo'' fiberoptic laser doppler blood flow probe (TSI, Minneapolis, MN) were used at the same location. Blood glucose was measured by finger stick every 7.5 min. One PT with a squamous cell CA with extensive necrosis had only a small increase in blood glucose and an increase in tumor pH. Blood flow readings were within 6.4-18.4ml/100g/min. Another PT with a squamous CA had a drop in tumor pH (7.46 to 7.05) as blood glucose increased from 85 to 137 mg/dl by 55 min. Blood flow remained in a range of 7.7-13.8 ml/100g/min with a mean of 11.4. The third PT with a sarcoma had tumor pH and blood glucose measurements on two occasions, with similar results. Blood glucose rose from approx. 100 to 150 mg/dl by 52.5 min with a drop in tumor pH from approx. 7.4 to 7.25. On the second trial, tumor blood flow was measured and, while erratic (6.4-24.9ml/100g/min), decreased by approx. 50%. These preliminary data show that the laser doppler blood flow technique is quite sensitive to movement artifact and interference by free hemoglobin. Currently, it is inconclusive whether blood flow is altered with blood glucose and tumor pH changes. Further studies may prove this to be a valuable tool in predicting tumor response to hyperthermia

Our experience of blood flow measurements using radioactive tracers

International Nuclear Information System (INIS)

Danet, Bernard.

1974-01-01

A critical study of blood flow measuring methods is proposed. After a review of the various diffusible and non-diffusible radioactive tracers and the corresponding detector systems, the principles which allow to measure blood flow from the data so obtained, are studied. There is a different principle of flow measurement for each type of tracer. The theory of flow measurement using non-diffusible tracers (human serum albumin labelled with 131 I or sup(99m)Tc, 113 In-labelled siderophiline) and its application to cardiac flow measurement are described first. Then the theory of flow measurement using diffusible tracers ( 133 Xe, 85 Kr) and its application to measurement of blood flow through tissues (muscles and kidney particularly) are described. A personal experience of this various flow measurements is reported. The results obtained, the difficulties encountered and the improvments proposed are developed [fr

Transcranial diffuse optical assessment of the microvascular reperfusion after thrombolysis for acute ischemic stroke.

Science.gov (United States)

Delgado-Mederos, Raquel; Gregori-Pla, Clara; Zirak, Peyman; Blanco, Igor; Dinia, Lavinia; Marín, Rebeca; Durduran, Turgut; Martí-Fàbregas, Joan

2018-03-01

In this pilot study, we have evaluated bedside diffuse optical monitoring combining diffuse correlation spectroscopy and near-infrared diffuse optical spectroscopy to assess the effect of thrombolysis with an intravenous recombinant tissue plasminogen activator (rtPA) on cerebral hemodynamics in an acute ischemic stroke. Frontal lobes of five patients with an acute middle cerebral artery occlusion were measured bilaterally during rtPA treatment. Both ipsilesional and contralesional hemispheres showed significant increases in cerebral blood flow, total hemoglobin concentration and oxy-hemoglobin concentration during the first 2.5 hours after rtPA bolus. The increases were faster and higher in the ipsilesional hemisphere. The results show that bedside optical monitoring can detect the effect of reperfusion therapy for ischemic stroke in real-time.

Spatial Temporal Image Correlation Spectroscopy (STICS) for Flow Analysis with Application for Blood Flow Mapping

International Nuclear Information System (INIS)

Rossow, Molly; Gratton, Enrico; Mantulin, William M.

2009-01-01

It is important for surgeons to be able to measure blood flow in exposed arterioles during surgery. We report our progress in the development of an optical technique that will measure blood flow in surgically exposed blood vessels and enable previously difficult measurements. By monitoring optical fluctuations, the optical technique, based on Spatial Temporal Image Correlation (STICS), will directly measure the velocity of micron-scale particles--such as red blood cells. It will complement existing technology and provide qualitative measurements that were not previously possible. It relies on the concept that blood, when viewed on a small enough scale, is an inhomogeneous substance. Individual blood cells passing between a near-infrared light source and a detector will cause fluctuations in the transmitted optical signal. The speed, direction, and flow pattern of blood cells can be determined from these optical fluctuations. We present a series of computer simulations and experiments on phantom and animal systems to test this technique's ability to map complex flow patterns.

Noxious heat and scratching decrease histamine-induced itch and skin blood flow.

Science.gov (United States)

Yosipovitch, Gil; Fast, Katharine; Bernhard, Jeffrey D

2005-12-01

The aim of this study was to assess the effect of thermal stimuli or distal scratching on skin blood flow and histamine-induced itch in healthy volunteers. Twenty-one healthy volunteers participated in the study. Baseline measurements of skin blood flow were obtained on the flexor aspect of the forearm. These measurements were compared with skin blood flow after various stimuli: heating the skin, cooling the skin, noxious cold 2 degrees C, noxious heat 49 degrees C, and scratching via a brush with controlled pressure. Afterwards histamine iontophoresis was performed and skin blood flow and itch intensity were measured immediately after the above-mentioned stimuli. Scratching reduced mean histamine-induced skin blood flow and itch intensity. Noxious heat pain increased basal skin blood flow but reduced histamine-induced maximal skin blood flow and itch intensity. Cold pain and cooling reduced itch intensity, but neither affected histamine-induced skin blood flow. Sub-noxious warming the skin did not affect the skin blood flow or itch intensity. These findings suggest that heat pain and scratching may inhibit itch through a neurogenic mechanism that also affects skin blood flow.

Assessment of myocardial viability using 123I-labeled iodophenylpentadecanoic acid at sustained low flow or after acute infarction and reperfusion.

Science.gov (United States)

Yang, J Y; Ruiz, M; Calnon, D A; Watson, D D; Beller, G A; Glover, D K

1999-05-01

123I-labeled iodophenylpentadecanoic acid (IPPA) is a synthetic fatty acid that may be useful for determination of myocardial viability. We investigated the uptake and clearance kinetics of this tracer in canine models of ischemia and infarction. In protocol 1, 185 MBq (5 mCi) 123I-IPPA were injected intravenously in 19 dogs with 50% left anterior descending artery (LAD) flow reduction. In 9 dogs, 201TI was coinjected. In protocol 2, 5 dogs underwent LAD occlusion for 3 h, and 123I-IPPA was injected 60 min after reperfusion. All dogs had flow measured by microspheres, regional systolic thickening by ultrasonic crystals and measurements of postmortem risk area and infarct size. Tracer activities were quantified by gamma well counting and by serial imaging. In protocol 1 dogs with sustained low flow (50% +/- 4%) and absence of systolic thickening (-3.2% +/- 1%), 123I-IPPA defect magnitude (LAD/left circumflex artery [LCX] count ratios) decreased from 0.65 +/- 0.02 to 0.74 +/- 0.02 at 30 min and to 0.84 +/- 0.03 at 2 h (P < 0.01), indicative of rest redistribution. Final transmural 123I-IPPA LAD/LCX activity ratio (0.99 +/- 0.05) was significantly greater than the flow ratio (0.53 +/- 0.04) at injection, confirming complete rest redistribution. The final 123I-IPPA activity ratio was significantly greater than the 201TI ratio over the 2-h period (P < 0.01). In protocol 2 dogs that underwent 3 h of total LAD occlusion and reflow (infarct size = 51% +/- 13% of risk area), viability was overestimated with 123I-IPPA, because uptake averaged 64% of normal in the central necrotic region, where flow averaged < 10% of normal. These findings suggest that serial 123I-IPPA imaging may be useful for assessing myocardial viability under conditions of sustained low flow and myocardial asynergy, such as appears to exist in patients with chronic coronary artery disease and depressed left ventricular function. In contrast, 123I-IPPA given early after reperfusion following prolonged

Left coronary arterial blood flow: Noninvasive detection by Doppler US

International Nuclear Information System (INIS)

Gramiak, R.; Holen, J.; Moss, A.J.; Gutierrez, O.H.; Picone, A.L.; Roe, S.A.

1986-01-01

Continuous wave (CW) and pulsed Doppler ultrasound studies with spectral analysis were used to detect the left coronary arterial blood flow in patients who were undergoing routine echocardiography. The pulmonary artery is a stable ultrasonic landmark from which detection of the blood flow can be effected. The left coronary artery can be distinguished by its blood flow toward the cardiac apex and by specific, functional flow features. Flow patterns vary among the left main, circumflex, and anterior descending arteries; patterns also vary with respiration cycles. In the present study, coronary arterial blood flow was detected in 58 of 70 patients (83%). Findings were validated by selectively injecting an agitated saline contrast medium into the left coronary artery and, in another study, by comparing human Doppler phasic flow waveforms with electromagnetic flowmeter recordings obtained in dogs

Evaluation of Pulmonary Reperfusion Injury in Rats Undergoing Mesenteric Ischemia and Reperfusion and Protective Effect of Postconditioning on this Process

Directory of Open Access Journals (Sweden)

Carlos Henrique Marques dos Santos

2015-10-01

Full Text Available ABSTRACT INTRODUCTION: Some publications have demonstrated the presence of lung reperfusion injury in mesenteric ischemia and reperfusion (I/R, but under to diverse methods. Postconditioning has been recognized as effective in preventing reperfusion injury in various organs and tissues. However, its effectiveness has not been evaluated in the prevention of lung reperfusion injury after mesenteric ischemia and reperfusion. OBJECTIVE: To evaluate the presence of pulmonary reperfusion injury and the protective effect of ischemic postconditioning on lung parenchyma in rats submitted to mesenteric ischemia and reperfusion. METHODS: Thirty Wistar rats were distributed into three groups: group A (10 rats, which was held mesenteric ischemia (30 minutes and reperfusion (60 minutes; group B (10 rats, ischemia and reperfusion, interspersed by postconditioning with two alternating cycles of reperfusion and reocclusion, for two minutes each; and group C (10 rats, ischemia and reperfusion interleaved by postconditioning with four alternating cycles of reperfusion and reocclusion of 30 seconds each. Finally, it was resected the upper lung lobe for histological analysis. RESULTS: There were mild lung lesions (grade 1 in all samples. There was no statistical difference between groups 1 and 2 (P >0.05. CONCLUSION: The mesenteric ischemia and reperfusion in rats for thirty and sixty minutes, respectively, caused mild reperfusion injury in lung. Postconditioning was not able to minimize the remote reperfusion injury and there was no difference comparing two cycles of two minutes with four cycles of 30 seconds.

Total hepatofugal portal blood flow in cirrhosis demonstrated by transhepatic portography

Energy Technology Data Exchange (ETDEWEB)

Burcharth, F; Aagaard, J

1988-01-01

We investigated 108 patients with cirrhosis of the liver and portal hypertension by percutaneous transhepatic portography to demonstrate the occurrence and frequency of total hepatofugal portal blood flow. Sixteen patients (14.8%) had a total hepatofugal portal blood flow. The aetiology of portal hypertension and the portal pressure did not differ from that in the group of patients with hepatopetal portal blood flow. A significantly higher percentage of patients in the group with hepatofugal flow had gastro-oesophageal varices (P < 0.025). All patients with varices had bled. Half of the patients in the group with hepatofugal blood flow had a false splenoportographic diagnosis of portal vein thrombosis. In conclusion, total hepatofugal postal blood flow exists more often than hitherto assumed. Hepatofugal blood flow does not relieve portal hypertension nor prevent development of gastro-oesophageal varices or bleeding.

Muscle blood flow at onset of dynamic exercise in humans.

Science.gov (United States)

Rådegran, G; Saltin, B

1998-01-01

To evaluate the temporal relationship between blood flow, blood pressure, and muscle contractions, we continuously measured femoral arterial inflow with ultrasound Doppler at onset of passive exercise and voluntary, one-legged, dynamic knee-extensor exercise in humans. Blood velocity and inflow increased (P dicrotic and diastolic blood pressure notches, respectively. Mechanical hindrance occurred (P dicrotic notch. The increase in blood flow (Q) was characterized by a one-component (approximately 15% of peak power output), two-component (approximately 40-70% of peak power output), or three-component exponential model (> or = 75% of peak power output), where Q(t) = Qpassive + delta Q1.[1 - e-(t - TD1/tau 1)]+ delta Q2.[1 - e-(t - TD2/tau 2)]+ delta Q3.[1 - e-(t - TD3/tau 3)]; Qpassive, the blood flow during passive leg movement, equals 1.17 +/- 0.11 l/min; TD is the onset latency; tau is the time constant; delta Q is the magnitude of blood flow rise; and subscripts 1-3 refer to the first, second, and third components of the exponential model, respectively. The time to reach 50% of the difference between passive and voluntary asymptotic blood flow was approximately 2.2-8.9 s. The blood flow leveled off after approximately 10-150 s, related to the power outputs. It is concluded that the elevation in blood flow with the first duty cycle(s) is due to muscle mechanical factors, but vasodilators initiate a more potent amplification within the second to fourth contraction.

Dynamics of blood flow: twenty years of achievement

International Nuclear Information System (INIS)

Rosendorff, C.

1988-01-01

The physiology of blood circulation has evolved from the descriptive phenomenology of William Harvey's time to an interdisciplinary science, involving elements of fluid dynamics, vessel wall mechanics, electrophysiology, cell biology, biochemistry and molecular biology. Most of these new developments have occured during the lifetime of the South African Medical Research Council. Highlights of the research undertaken by the Council regarding circulatory physiology are given. In the 1960s the use of xenon-133 to study the flow of blood to the brain resulted in the first systematic description of cerebral blood flow and its control by sympathetic nerves. During the 1970s this technique was refined and the use of radioactive microspheres for the measurement of tissue blood flow was developed. Research concerning the control of blood vessels in the kidney was also carried out, and this showed that the sympathetic nerves control renal blood flow by releasing a local hormone called renin. The renal release of renin was later recognised as being important in the control of blood pressure. Another development was the discovery that vascular sensitivity to noradrenaline was increased in certain types of liver diseases. An analysis of the blood of patients with obstructive jaundice showed that the substance responsible for this noradrenaline effect was a combination of cholesterol and lipo-protein. This led to the theory that excessive cholesterol in the blood may be dangerous. In the late 1970s a shift in research emphasis to coronary artery physiology occurred and the 1980s saw research move into the area of cell biology

Intestinal ischemia-reperfusion injury augments intestinal mucosal injury and bacterial translocation in jaundiced rats.

Science.gov (United States)

Yüksek, Yunus Nadi; Kologlu, Murat; Daglar, Gül; Doganay, Mutlu; Dolapci, Istar; Bilgihan, Ayse; Dolapçi, Mete; Kama, Nuri Aydin

2004-01-01

The aim of this study was to evaluate local effects and degree of bacterial translocation related with intestinal ischemia-reperfusion injury in a rat obstructive jaundice model. Thirty adult Sprague-Dawley rats (200-250 g) were divided into three groups; including Group 1 (jaundice group), Group 2 (jaundice-ischemia group) and Group 3 (ischemia group). All rats had 2 laparotomies. After experimental interventions, tissue samples for translocation; liver and ileum samples for histopathological examination, 25 cm of small intestine for mucosal myeloperoxidase and malondialdehyde levels and blood samples for biochemical analysis were obtained. Jaundiced rats had increased liver enzyme levels and total and direct bilirubin levels (p<0.05). Intestinal mucosal myeloperoxidase and malondialdehyde levels were found to be high in intestinal ischemia-reperfusion groups (p<0.05). Intestinal mucosal damage was more severe in rats with intestinal ischemia-reperfusion after bile duct ligation (p<0.05). Degree of bacterial translocation was also found to be significantly high in these rats (p<0.05). Intestinal mucosa is disturbed more severely in obstructive jaundice with the development of ischemia and reperfusion. Development of intestinal ischemia-reperfusion in obstructive jaundice increases bacterial translocation.

Neural control of adrenal medullary and cortical blood flow during hemorrhage

International Nuclear Information System (INIS)

Breslow, M.J.; Jordan, D.A.; Thellman, S.T.; Traystman, R.J.

1987-01-01

Hemorrhagic hypotension produces an increase in adrenal medullary blood flow and a decrease in adrenal cortical blood flow. To determine whether changes in adrenal blood flow during hemorrhage are neurally mediated, the authors compared blood flow responses following adrenal denervation (splanchnic nerve section) with changes in the contralateral, neurally intact adrenal. Carbonized microspheres labeled with 153 Gd, 114 In, 113 Sn, 103 Ru, 95 Nb or 46 Se were used. Blood pressure was reduced and maintained at 60 mmHg for 25 min by hemorrhage into a pressurized bottle system. Adrenal cortical blood flow decreased to 50% of control with hemorrhage in both the intact and denervated adrenal. Adrenal medullary blood flow increased to four times control levels at 15 and 25 min posthemorrhage in the intact adrenal, but was reduced to 50% of control at 3, 5, and 10 min posthemorrhage in the denervated adrenal. In a separate group of dogs, the greater splanchnic nerve on one side was electrically stimulated at 2, 5, or 15 Hz for 40 min. Adrenal medullary blood flow increased 5- to 10-fold in the stimulated adrenal but was unchanged in the contralateral, nonstimulated adrenal. Adrenal cortical blood flow was not affected by nerve stimulation. They conclude that activity of the splanchnic nerve profoundly affects adrenal medullary vessels but not adrenal cortical vessels and mediates the observed increase in adrenal medullary blood flow during hemorrhagic hypotension

Age and gender related differences in aortic blood flow

DEFF Research Database (Denmark)

Traberg, Marie Sand; Pedersen, Mads Møller; Hemmsen, Martin Christian

2012-01-01

The abdominal aorta (AA) is predisposed to development of abdominal aneurysms (AAA), a focal dilatation of the artery with fatal consequences if left untreated. The blood flow patterns in the AA is thought to play an important role in the development of AAA. The purpose of this work is to investi......The abdominal aorta (AA) is predisposed to development of abdominal aneurysms (AAA), a focal dilatation of the artery with fatal consequences if left untreated. The blood flow patterns in the AA is thought to play an important role in the development of AAA. The purpose of this work...... is to investigate the blood flow pat- terns within a group of healthy volunteers (4 females, 7 males) aged 23 to 76 years to identify changes and differences related to age and gender. The healthy volunteers were categorized by gender (male/female) and age (below/above 35 years). Subject-specific flow and geometry...... to elderly. Thus, changes in blood flow patterns in the AA related to age and gender is observed. Further investigations are needed to determine the relation between changes in blood flow patterns and AAA development....

Prevention of reperfusion lung injury by lidocaine in isolated rat lung ventilated with higher oxygen levels.

Directory of Open Access Journals (Sweden)

Das K

2003-01-01

Full Text Available BACKGROUND: Lidocaine, an antiarrhythmic drug has been shown to be effective against post-ischaemic reperfusion injury in heart. However, its effect on pulmonary reperfusion injury has not been investigated. AIMS: We investigated the effects of lidocaine on a postischaemic reperfused rat lung model. MATERIALS AND METHODS: Lungs were isolated and perfused at constant flow with Krebs-Henseilet buffer containing 4% bovine serum albumin, and ventilated with 95% oxygen mixed with 5% CO2. Lungs were subjected to ischaemia by stopping perfusion for 60 minutes followed by reperfusion for 10 minutes. Ischaemia was induced in normothermic conditions. RESULTS: Postischaemic reperfusion caused significant (p < 0.0001 higher wet-to-dry lung weight ratio, pulmonary arterial pressure and peak airway pressure compared to control lungs. Lidocaine, at a dose of 5mg/Kg b.w. was found to significantly (p < 0.0001 attenuate the increase in the wet-to-dry lung weight ratio, pulmonary arterial pressure and peak airway pressure observed in post-ischaemic lungs. CONCLUSION: Lidocaine is effective in preventing post-ischaemic reperfusion injury in isolated, perfused rat lung.

Modeling skin blood flow: a neuro-physiological approach

NARCIS (Netherlands)

Kingma, B.R.M.; Saris, W.H.M.; Frijns, A.J.H.; Steenhoven, van A.A.; Marken Lichtenbelt, van W.D.

2010-01-01

In humans skin blood flow (SBF) plays a major role in body heat loss. Therefore the accuracy of models ofhuman thermoregulation depends for a great deal on their ability to predict skin blood flow. Most SBFmodelsuse body temperatures directly for calculation of skin perfusion. However, humans do not

Roles for C-X-C chemokines and C5a in lung injury after hindlimb ischemia-reperfusion

DEFF Research Database (Denmark)

Bless, N M; Warner, R L; Padgaonkar, V A

1999-01-01

We evaluated the roles of the C-X-C chemokines cytokine-induced neutrophil chemoattractant (CINC) and macrophage inflammatory protein-2 (MIP-2) as well as the complement activation product C5a in development of lung injury after hindlimb ischemia-reperfusion in rats. During reperfusion, CD11b...... and CD18, but not CD11a, were upregulated on neutrophils [bronchoalveolar lavage (BAL) and blood] and lung macrophages. BAL levels of CINC and MIP-2 were increased during the ischemic and reperfusion periods. Treatment with either anti-CINC or anti-MIP-2 IgG significantly reduced lung vascular......, 58, and 23%, respectively (P MIP-2 as well as the complement activation product C5a are required for lung neutrophil recruitment and full induction of lung injury after hindlimb ischemia-reperfusion in rats....

The measurement of limb blood flow using technetium-labelled red blood cells

International Nuclear Information System (INIS)

Parkin, A; Robinson, P.J.; Wiggins, P.A.; Leveson, S.H.; Salter, M.C.P.; Matthews, I.F.; Ware, F.M.

1986-01-01

A method for measuring blood flow below the knee during reactive hyperaemia induced by 3 min of arterial occlusion has been developed. Subjects are positioned with lower limbs within the field of view of a gamma camera and pneumatic cuffs are placed below the knees to isolate the blood and induce a hyperaemic response. The remaining blood pool is labelled with 99 Tcsup(m)-labelled red cells. Blood flows have been derived from the initial gradients of time-activity curves and from equilibrium blood sampling. The technique has been validated using a tissue-equivalent leg phantom and peristaltic pump. The method has been applied to a small group of patients with peripheral vascular disease and to normal controls. The mean value (+-SD) of limb perfusion for normal controls was found to be 16.4+-3.0 ml/100 ml/min and for patients with intermittent claudication was 5.1+-2.6 ml/100 ml/min. Flow measurements are found to correlate with clinical findings and with symptoms. Reproducibility (established by repeated measurements) is high. The method is well tolerated even by patients suffering from rest pain. (author)

Brain blood flow and blood pressure during hypoxia in the epaulette shark Hemiscyllium ocellatum, a hypoxia-tolerant elasmobranch.

Science.gov (United States)

Söderström, V; Renshaw, G M; Nilsson, G E

1999-04-01

The key to surviving hypoxia is to protect the brain from energy depletion. The epaulette shark (Hemiscyllium ocellatum) is an elasmobranch able to resist energy depletion and to survive hypoxia. Using epi-illumination microscopy in vivo to observe cerebral blood flow velocity on the brain surface, we show that cerebral blood flow in the epaulette shark is unaffected by 2 h of severe hypoxia (0.35 mg O2 l-1 in the respiratory water, 24 C). Thus, the epaulette shark differs from other hypoxia- and anoxia-tolerant species studied: there is no adenosine-mediated increase in cerebral blood flow such as that occurring in freshwater turtles and cyprinid fish. However, blood pressure showed a 50 % decrease in the epaulette shark during hypoxia, indicating that a compensatory cerebral vasodilatation occurs to maintain cerebral blood flow. We observed an increase in cerebral blood flow velocity when superfusing the normoxic brain with adenosine (making sharks the oldest vertebrate group in which this mechanism has been found). The adenosine-induced increase in cerebral blood flow velocity was reduced by the adenosine receptor antagonist aminophylline. Aminophylline had no effect upon the maintenance of cerebral blood flow during hypoxia, however, indicating that adenosine is not involved in maintaining cerebral blood flow in the epaulette shark during hypoxic hypotension.

The effects of sulforaphane on the liver and remote organ damage in hepatic ischemia-reperfusion model formed with pringle maneuver in rats.

Science.gov (United States)

Oguz, Abdullah; Kapan, Murat; Kaplan, Ibrahim; Alabalik, Ulas; Ulger, Burak Veli; Uslukaya, Omer; Turkoglu, Ahmet; Polat, Yilmaz

2015-06-01

The purpose of this study was to investigate the effect of Sulforaphane on ischemia/ reperfusion (IR) injury of the liver and distant organs resulting from liver blood flow arrest. Fourty Wistar rats were assigned into four groups, each included 10 rats were used. Group I as only laparatomy, Group II laparatomy and Sulforaphane application, Group III hepatic IR; and Group IV as hepatic IR and Sulforaphane application group. Animals were subjected to liver ischemia for 30 min and then reperfusion is started. 5 mg/kg Sulforaphane was applied via oral lavage 15 minutes before initiating the experimental study. Blood samples were taken from the animals for biochemical analysis at 60th minutes of the experiment in the first and second groups; 30 minutes after beginning reperfusion in the third and forth groups. Simultaneously, liver, lung and kidney tissues were sampled for biochemical and histopathological examinations. The administration of sulforaphane significantly reduced the serum TOA and liver TOA levels, increased the serum TAC and liver TAC levels and also decreased The OSI and liver OSI levels. In the histopathologic examination, the injury was reduced by the administration of sulforaphane. Administration of sulforaphane did not lead to any significant changes in any parameter including histopathological parameters in both the kidney and the lung. Sulforaphane reduced the liver oxidative stress from I/R injury. A histological injury in liver was reduced by sulforaphane administration. However, there were no significant effects of sulforaphane on the remote organ injuries induced by IR. Copyright © 2015 IJS Publishing Group Limited. Published by Elsevier Ltd. All rights reserved.

Quantification of cerebral blood flow via Duplex sonography

International Nuclear Information System (INIS)

Vogl, G.; Pohl, P.; Willeit, J.; Aichner, F.

1987-01-01

An attempt was made to measure quantitatively the total cerebral blood flow by means of Duplex sonography. In a group of healthy young subjects a median value for total cerebral blood flow was obtained amounting to 469 ml/min ± 30%, repeat measurements yielded a maximum deviation of ± 11%. In three patients the values obtained after severe apoplectic insult due to occlusion of the internal carotid artery were definitely below the value of the group of healthy subjects, whereas the value for the total blood flow was in the upper range of normal values in a patient with occlusion of the a. cerebri media. Comparative measurements of the regional cerebral blood flow with xenon 13 yielded in those patients with occlusion of the internal carotid artery a markedly reduced mean flow and in the patient with occlusion of the a. cerebri media a less markedly reduced mean flow. Regionally reduced perfusion was seen in all the four patients in the range of the clinically and computer tomographically well-known ischaemia zone. Thanks to the simplicity of this sonographic examination method it could be a useful decision parameter in determining the indication for a reconstruction of the carotid artery, especially in asymptotic patients. (orig.) [de

Computational Analysis of Human Blood Flow

Science.gov (United States)

Panta, Yogendra; Marie, Hazel; Harvey, Mark

2009-11-01

Fluid flow modeling with commercially available computational fluid dynamics (CFD) software is widely used to visualize and predict physical phenomena related to various biological systems. In this presentation, a typical human aorta model was analyzed assuming the blood flow as laminar with complaint cardiac muscle wall boundaries. FLUENT, a commercially available finite volume software, coupled with Solidworks, a modeling software, was employed for the preprocessing, simulation and postprocessing of all the models.The analysis mainly consists of a fluid-dynamics analysis including a calculation of the velocity field and pressure distribution in the blood and a mechanical analysis of the deformation of the tissue and artery in terms of wall shear stress. A number of other models e.g. T branches, angle shaped were previously analyzed and compared their results for consistency for similar boundary conditions. The velocities, pressures and wall shear stress distributions achieved in all models were as expected given the similar boundary conditions. The three dimensional time dependent analysis of blood flow accounting the effect of body forces with a complaint boundary was also performed.

Cerebral blood flow in Binswanger's disease

International Nuclear Information System (INIS)

Kawabata, Keita; Tachibana, Hisao; Sugita, Minoru

1991-01-01

Eight patients with a clinical diagnosis of Binswanger's disease (BD) were evaluated with I-123 IMP SPECT. The SPECT findings were compared with those in 7 other patients with Alzheimer's disease (AD) and 9 normal subjects. The ratios of I-123 IMP in the temporal cortex, thalamus, and basal ganglia to that in the cerebellum were lower in the BD group than the normal group. The BD group had a higher ratio of the occipital cortex/the cerebellum than the control group, suggesting a decreased blood flow in the cerebellum. When I-123 IMP ratio in various areas to that in the occipital cortex was examined, both the BD and AD groups seemed to have a decreased blood flow over the whole cerebrum. The BD group had a lower I-123 IMP uptake in the thalamus and basal ganglia, and the AD group had it in the parietal cortex, relative to the occipital cortex. Blood flow patterns for BD were found to be different from those for AD. This suggests the difference in areas responsible for etiology between BD and AD. (N.K.)

Optical measurement of blood flow in exercising skeletal muscle: a pilot study

Science.gov (United States)

Wang, Detian; Baker, Wesley B.; Parthasarathy, Ashwin B.; Zhu, Liguo; Li, Zeren; Yodh, Arjun G.

2017-07-01

Blood flow monitoring during rhythm exercising is very important for sports medicine and muscle dieases. Diffuse correlation spectroscopy(DCS) is a relative new invasive way to monitor blood flow but suffering from muscle fiber motion. In this study we focus on how to remove exercise driven artifacts and obtain accurate estimates of the increase in blood flow from exercise. Using a novel fast software correlator, we measured blood flow in forearm flexor muscles of N=2 healthy adults during handgrip exercise, at a sampling rate of 20 Hz. Combining the blood flow and acceleration data, we resolved the motion artifact in the DCS signal induced by muscle fiber motion, and isolated the blood flow component of the signal from the motion artifact. The results show that muscle fiber motion strongly affects the DCS signal, and if not accounted for, will result in an overestimate of blood flow more than 1000%. Our measurements indicate rapid dilation of arterioles following exercise onset, which enabled blood flow to increase to a plateau of 200% in 10s. The blood flow also rapidly recovered to baseline following exercise in 10s. Finally, preliminary results on the dependence of blood flow from exercise intensity changes will be discussed.

Thermographic venous blood flow characterization with external cooling stimulation

Science.gov (United States)

Saxena, Ashish; Ng, E. Y. K.; Raman, Vignesh

2018-05-01

Experimental characterization of blood flow in a human forearm is done with the application of continuous external cooling based active thermography method. Qualitative and quantitative detection of the blood vessel in a thermal image is done, along with the evaluation of blood vessel diameter, blood flow direction, and velocity in the target blood vessel. Subtraction based image manipulation is performed to enhance the feature contrast of the thermal image acquired after the removal of external cooling. To demonstrate the effect of occlusion diseases (obstruction), an external cuff based occlusion is applied after the removal of cooling and its effect on the skin rewarming is studied. Using external cooling, a transit time method based blood flow velocity estimation is done. From the results obtained, it is evident that an external cooling based active thermography method can be used to develop a diagnosis tool for superficial blood vessel diseases.

Reperfusion is a more accurate predictor of follow-up infarct volume than recanalization: a proof of concept using CT in acute ischemic stroke patients.

Science.gov (United States)

Soares, Bruno P; Tong, Elizabeth; Hom, Jason; Cheng, Su-Chun; Bredno, Joerg; Boussel, Loic; Smith, Wade S; Wintermark, Max

2010-01-01

The purpose of this study was to compare recanalization and reperfusion in terms of their predictive value for imaging outcomes (follow-up infarct volume, infarct growth, salvaged penumbra) and clinical outcome in acute ischemic stroke patients. Twenty-two patients admitted within 6 hours of stroke onset were retrospectively included in this study. These patients underwent a first stroke CT protocol including CT-angiography (CTA) and perfusion-CT (PCT) on admission, and similar imaging after treatment, typically around 24 hours, to assess recanalization and reperfusion. Recanalization was assessed by comparing arterial patency on admission and posttreatment CTAs; reperfusion, by comparing the volumes of CBV, CBF, and MTT abnormality on admission and posttreatment PCTs. Collateral flow was graded on the admission CTA. Follow-up infarct volume was measured on the discharge noncontrast CT. The groups of patients with reperfusion, no reperfusion, recanalization, and no recanalization were compared in terms of imaging and clinical outcomes. Reperfusion (using an MTT reperfusion index >75%) was a more accurate predictor of follow-up infarct volume than recanalization. Collateral flow and recanalization were not accurate predictors of follow-up infarct volume. An interaction term was found between reperfusion and the volume of the admission penumbra >50 mL. Our study provides evidence that reperfusion is a more accurate predictor of follow-up infarct volume in acute ischemic stroke patients than recanalization. We recommend an MTT reperfusion index >75% to assess therapy efficacy in future acute ischemic stroke trials that use perfusion-CT.

Heterogeneity of cerebral blood flow: a fractal approach

International Nuclear Information System (INIS)

Kuikka, J.T.; Hartikainen, P.

2000-01-01

Aim: We demonstrate the heterogeneity of regional cerebral blood flow using a fractal approach and single-photon emission computed tomography (SPECT). Method: Tc-99m-labelled ethylcysteine dimer was injected intravenously in 10 healthy controls and in 10 patients with dementia of frontal lobe type. The head was imaged with a gamma camera and transaxial, sagittal and coronal slices were reconstructed. Two hundred fifty-six symmetrical regions of interest (ROIs) were drawn onto each hemisphere of functioning brain matter. Fractal analysis was used to examine the spatial heterogeneity of blood flow as a function of the number of ROIs. Results: Relative dispersion (=coefficient of variation of the regional flows) was fractal-like in healthy subjects and could be characterized by a fractal dimension of 1.17±0.05 (mean±SD) for the left hemisphere and 1.15±0.04 for the right hemisphere, respectively. The fractal dimension of 1.0 reflects completely homogeneous blood flow and 1.5 indicates a random blood flow distribution. Patients with dementia of frontal lobe type had a significantly lower fractal dimension of 1.04±0.03 than in healthy controls. (orig.) [de

Low cerebral blood flow in hypotensive perinatal distress

International Nuclear Information System (INIS)

Lou, H.C.; Lassen, N.A.; Friis-Hansen, B.

1977-01-01

Hypoxic brain injury is the most important neurological problem in the neonatal period and accounts for more neurological deficits in children than any other lesion. The neurological deficits are notably mental retardation, epilepsy and cerebral palsy. The pathogenesis has hitherto been poorly understood. Arterial hypoxia has been taken as the obvious mechanism but this does not fully explain the patho-anatomical findings. In the present investigation we have examined the arterial blood pressure and the cerebral blood flow in eight infants a few hours after birth. The 133Xe clearance technique was used for the cerebral blood flow measurements. The study confirmed that perinatal distress may be associated with low arterial blood pressure, and it was shown that cerebral blood flow is very low, 20 ml/100 g/min or less, in hypotensive perinatal distress. It is concluded that cerebral ischaemia plays a crucial role in the development of perinatal hypoxic brain injury. (author)

Esophageal blood flow in the cat. Normal distribution and effects of acid perfusion

International Nuclear Information System (INIS)

Hollwarth, M.E.; Smith, M.; Kvietys, P.R.; Granger, D.N.

1986-01-01

The radioactive microsphere technique was used to estimate blood flow to different regions of the esophagus and to adjacent regions of the stomach before and after perfusion of the esophagus with hydrochloric acid (pH 1.5) for 5 min. Under resting conditions total blood flow, as well as blood flow to the mucosal-submucosal layer and the muscular layer, to both sphincters was significantly higher than to the esophageal body. Blood flow to the adjacent regions of the stomach was significantly higher than esophageal blood flow. Acid perfusion resulted in a large increase in total blood flow in both sphincters and the lower esophageal body. Gastric blood flow was not altered by acid perfusion. The esophageal hyperemia resulted primarily from an increase in blood flow to the muscular layer; mucosal-submucosal blood flow was increased only in the lower esophageal sphincter. The present study indicates that short periods (5 min) of gastroesophageal reflux may increase esophageal blood flow

Effect of age on cerebral blood flow during hypothermic cardiopulmonary bypass

International Nuclear Information System (INIS)

Brusino, F.G.; Reves, J.G.; Smith, L.R.; Prough, D.S.; Stump, D.A.; McIntyre, R.W.

1989-01-01

Cerebral blood flow was measured in 20 patients by xenon 133 clearance methodology during nonpulsatile hypothermic cardiopulmonary bypass to determine the effect of age on regional cerebral blood flow during these conditions. Measurements of cerebral blood flow at varying perfusion pressures were made in patients arbitrarily divided into two age groups at nearly identical nasopharyngeal temperature, hematocrit value, and carbon dioxide tension and with equal cardiopulmonary bypass flows of 1.6 L/min/m2. The range of mean arterial pressure was 30 to 110 mm Hg for group I (less than or equal to 50 years of age) and 20 to 90 mm Hg for group II (greater than or equal to 65 years of age). There was no significant difference (p = 0.32) between the mean arterial pressure in group I (54 +/- 28 mm Hg) and that in group II (43 +/- 21 mm Hg). The range of cerebral blood flow was 14.8 to 29.2 ml/100 gm/min for group I and 13.8 to 37.5 ml/100 gm/min for group II. There was no significant difference (p = 0.37) between the mean cerebral blood flow in group I (21.5 +/- 4.6 ml/100 gm/min) and group II (24.3 +/- 8.1 ml/100 gm/min). There was a poor correlation between mean arterial pressure and cerebral blood flow in both groups: group I, r = 0.16 (p = 0.67); group II, r = 0.5 (p = 0.12). In 12 patients, a second cerebral blood flow measurements was taken to determine the effect of mean arterial pressure on cerebral blood flow in the individual patient. Changes in mean arterial pressure did not correlate with changes in cerebral blood flow (p less than 0.90). We conclude that age does not alter cerebral blood flow and that cerebral blood flow autoregulation is preserved in elderly patients during nonpulsatile hypothermic cardiopulmonary bypass

Protective Effect of CXCR3+CD4+CD25+Foxp3+ Regulatory T Cells in Renal Ischemia-Reperfusion Injury

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Cao Jun

2015-01-01

Full Text Available Regulatory T cells (Tregs suppress excessive immune responses and are potential therapeutic targets in autoimmune disease and organ transplantation rejection. However, their role in renal ischemia-reperfusion injury (IRI is unclear. Levels of Tregs and expression of CXCR3 in Tregs were analyzed to investigate their function in the early phase of renal IRI. Mice were randomly divided into Sham, IRI, and anti-CD25 (PC61 + IRI groups. The PC61 + IRI group was established by i.p. injection of PC61 monoclonal antibody (mAb to deplete Tregs before renal ischemia. CD4+CD25+Foxp3+ Tregs and CXCR3 on Tregs were analyzed by flow cytometry. Blood urea nitrogen (BUN, serum creatinine (Scr levels, and tubular necrosis scores, all measures of kidney injury, were greater in the IRI group than in the Sham group. Numbers of Tregs were increased at 72 h after reperfusion in kidney. PC61 mAb preconditioning decreased the numbers of Tregs and aggravated kidney injury. There was no expression of CXCR3 on Tregs in normal kidney, while it expanded at 72 h after reperfusion and inversely correlated with BUN, Scr, and kidney histology score. This indicated that recruitment of Tregs into the kidney was related to the recovery of renal function after IRI and CXCR3 might be involved in the migration of Tregs.

Role of hypotension in decreasing cerebral blood flow in porcine endotoxemia

International Nuclear Information System (INIS)

Miller, C.F.; Breslow, M.J.; Shapiro, R.M.; Traystman, R.J.

1987-01-01

The role of reduced arterial blood pressure (MAP) in decreasing cerebral blood flow (CBF) during endotoxemia was studied in pentobarbital-anesthetized pigs. Microspheres were used to measure regional CBF changes during MAP manipulations in animals with and without endotoxin. Endotoxin decreased MAP to 50 mmHg and decreased blood flow to the cortex and cerebellum without affecting cerebral cortical oxygen consumption (CMRo 2 ). Elevating MAP from 50 to 70 mmHg during endotoxemia with norepinephrine did not change cortical blood flow or CMRo 2 but increased cerebellar blood flow. Brain stem blood flow was not affected by endotoxin or norepinephrine. When MAP was decreased to 50 mmHg by hemorrhage without endotoxin, no change in blood flow to cortex, cerebellum, or brain stem was observed from base-line levels. These results suggest that decreased MAP below a lower limit for cerebral autoregulation does not account for the decreased CBF observed after endotoxin

Mechanisms of temporal variation in single-nephron blood flow in rats

DEFF Research Database (Denmark)

Yip, K P; Holstein-Rathlou, N H; Marsh, D J

1993-01-01

Modified laser-Doppler velocimetry was used to determine the number of different mechanisms regulating single-nephron blood flow. Two oscillations were identified in star vessel blood flow, one at 20-50 mHz and another at 100-200 mHz. Tubuloglomerular feedback (TGF) mediates the slower oscillation......, and the faster one is probably myogenic in origin. Acute hypertension increased autospectral power in the 20-50 mHz and 100-200 mHz frequency bands to 282 +/- 50 and 248 +/- 64%, respectively, of control even though mean single-nephron blood flow was autoregulated. Mean blood flow increased 24.6 +/- 6.1% when...... components in efferent arteriole blood flow....

Viscoelastic capillary flow: the case of whole blood

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David Rabaud

2016-07-01

Full Text Available The dynamics of spontaneous capillary flow of Newtonian fluids is well-known and can be predicted by the Lucas-Washburn-Rideal (LWR law. However a wide variety of viscoelastic fluids such as alginate, xanthan and blood, does not exhibit the same Newtonian behavior.In this work we consider the Herschel-Bulkley (HB rheological model and Navier-Stokes equation to derive a generic expression that predicts the capillary flow of non-Newtonian fluids. The Herschel-Bulkley rheological model encompasses a wide variety of fluids, including the Power-law fluids (also called Ostwald fluids, the Bingham fluids and the Newtonian fluids. It will be shown that the proposed equation reduces to the Lucas-Washburn-Rideal law for Newtonian fluids and to the Weissenberg-Rabinowitsch-Mooney (WRM law for power-law fluids. Although HB model cannot reduce to Casson’s law, which is often used to model whole blood rheology, HB model can fit the whole blood rheology with the same accuracy.Our generalized expression for the capillary flow of non-Newtonian fluid was used to accurately fit capillary flow of whole blood. The capillary filling of a cylindrical microchannel by whole blood was monitored. The blood first exhibited a Newtonian behavior, then after 7 cm low shear stress and rouleaux formation made LWR fails to fit the data: the blood could not be considered as Newtonian anymore. This non-Newtonian behavior was successfully fit by the proposed equation.

Subcutaneous blood flow in man during sleep with continous epdural anaesthesia

DEFF Research Database (Denmark)

Sindrup, JH; Petersen, Lars Jelstrup; Kastrup, Jens

1996-01-01

BACKGROUND: Subcutaneous blood flow increases during sleep and we evaluated if this increase is affected by epidural anaesthesia. METHODS: Lower leg subcutaneous blood flow was determined by 133Xenon clearance in ten subjects during continous epidural anaesthesia at L2-L3 including eight hours...... of sleep, while the opper abdominal subcutaneous blood flow served as control. RESULTS: Epidural anaesthesia to the level of the umbilicus was followed by an increase in the lower leg subcutaneous blood flow fra 3.4 (1.8-6.3) to 7.8 (3.6-16.9) ml min-1 (median and range; P....4-7.6) ml min-1 100 g-1 after 88 (45-123) min. In contrast, until the period of sleep the upper abdominal region blood flow remained at 5.2 (3.2-6.4) ml min-1 100 g-1. During sleep, lower leg subcutaneous blood flow did not change significantly, but the upper abdominal flow increased to 6.2 (5.2-7.2) ml min...

Transplacental diffusion and blood flow of gravid bovine uterus

International Nuclear Information System (INIS)

Reynolds, L.P.; Ferrell, C.L.; Ford, S.P.

1985-01-01

Electromagnetic blood flow transducers and uterine arterial, uterine venous, umbilical venous, fetal femoral arterial, and fetal femoral venous catheters were implanted in 11 cows on day 161 +/- 4 of gestation. Antipyrine (0.66 M) plus NaCl (0.16 M) dissolved in deuterium oxide (D 2 O), or H 2 O, was infused at a constant rate into the fetal femoral vein catheter. Concentrations of antipyrine and D 2 O in uterine arterial and venous blood and antipyrine in fetal arterial and umbilical venous blood, as well as middle uterine arterial blood flow (electromagnetic transducer), were determined. Antipyrine and D 2 O gave similar estimates (steady-state diffusion method) of gravid uterine blood flow. In addition, the slope of the regression of D 2 O on antipyrine estimates was not different from one. Electromagnetic transducers gave estimates of uterine blood flow that were 32-42% of those obtained with steady-state diffusion but were correlated with estimates obtained by use of both antipyrine and D 2 O. The transplacental clearance rate of antipyrine was similar (per kg placenta) to that observed in ewes. It was suggested that the maternal and fetal microvasculatures of the bovine placenta could have a concurrent arrangement with vascular shunts or maldistribution of flows, as has been suggested for the ewe

Obestatin Accelerates the Recovery in the Course of Ischemia/Reperfusion-Induced Acute Pancreatitis in Rats.

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Jakub Bukowczan

Full Text Available Several previous studies have shown that obestatin exhibits protective and regenerative effects in some organs including the stomach, kidney, and the brain. In the pancreas, pretreatment with obestatin inhibits the development of cerulein-induced acute pancreatitis, and promotes survival of pancreatic beta cells and human islets. However, no studies investigated the effect of obestatin administration following the onset of experimental acute pancreatitis.The aim of this study was to evaluate the impact of obestatin therapy in the course of ischemia/reperfusion-induced pancreatitis. Moreover, we tested the influence of ischemia/reperfusion-induced acute pancreatitis and administration of obestatin on daily food intake and pancreatic exocrine secretion.Acute pancreatitis was induced by pancreatic ischemia followed by reperfusion of the pancreas. Obestatin (8 nmol/kg/dose was administered intraperitoneally twice a day, starting 24 hours after the beginning of reperfusion. The effect of obestatin in the course of necrotizing pancreatitis was assessed between 2 and 14 days, and included histological, functional, and biochemical analyses. Secretory studies were performed on the third day after sham-operation or induction of acute pancreatitis in conscious rats equipped with chronic pancreatic fistula.Treatment with obestatin ameliorated morphological signs of pancreatic damage including edema, vacuolization of acinar cells, hemorrhages, acinar necrosis, and leukocyte infiltration of the gland, and led to earlier pancreatic regeneration. Structural changes were accompanied by biochemical and functional improvements manifested by accelerated normalization of interleukin-1β level and activity of myeloperoxidase and lipase, attenuation of the decrease in pancreatic DNA synthesis, and by an improvement of pancreatic blood flow. Induction of acute pancreatitis by pancreatic ischemia followed by reperfusion significantly decreased daily food intake and

Multidetector row computed tomography noninvasively assesses coronary reperfusion after thrombolytic therapy in patients with ST elevation myocardial infarction

International Nuclear Information System (INIS)

Shin, Dong-Il; Won, Yoo-Dong; Chang, Kiyuk

2006-01-01

The study objective was to assess the efficacy of 16-slice multidetector row computed tomography (MDCT) in estimating residual stenosis and successful reperfusion after thrombolysis in patients with ST-elevation myocardial infarction (STEMI). A total of 31 patients with STEMI underwent MDCT scanning within 6 h (mean 4.6±1.1) after thrombolysis and the results for detection of significant residual stenosis and distal flow of the infarct-related artery were compared with those from conventional coronary angiography (CCAG) performed within 24 h (mean 12.1±5.6) after the MDCT scan. Successful reperfusion was defined as Thrombolysis In Myocardial Infarction flow 2 or 3 on CCAG and full contrast enhancement of the distal artery landmarks on MDCT. A final analysis was performed using 24 patients (312 segments). MDCT had a positive predictive value of 73.3% and a negative predictive value of 95.1% for detecting significant residual stenosis. It accurately estimated 17 of 18 patients (94.4%) with successful reperfusion and 5 of 6 (83.3%) with failed reperfusion on the basis of comparison with CCAG. MDCT demonstrated high accuracy not only for the detecting residual stenosis, but also for assessing successful reperfusion after thrombolytic therapy in patients with STEMI. (author)

Intratracheal Administration of Small Interfering RNA Targeting Fas Reduces Lung Ischemia-Reperfusion Injury.

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Del Sorbo, Lorenzo; Costamagna, Andrea; Muraca, Giuseppe; Rotondo, Giuseppe; Civiletti, Federica; Vizio, Barbara; Bosco, Ornella; Martin Conte, Erica L; Frati, Giacomo; Delsedime, Luisa; Lupia, Enrico; Fanelli, Vito; Ranieri, V Marco

2016-08-01

Lung ischemia-reperfusion injury is the main cause of primary graft dysfunction after lung transplantation and results in increased morbidity and mortality. Fas-mediated apoptosis is one of the pathologic mechanisms involved in the development of ischemia-reperfusion injury. We hypothesized that the inhibition of Fas gene expression in lungs by intratracheal administration of small interfering RNA could reduce lung ischemia-reperfusion injury in an ex vivo model reproducing the procedural sequence of lung transplantation. Prospective, randomized, controlled experimental study. University research laboratory. C57/BL6 mice weighing 28-30 g. Ischemia-reperfusion injury was induced in lungs isolated from mice, 48 hours after treatment with intratracheal small interfering RNA targeting Fas, control small interfering RNA, or vehicle. Isolated lungs were exposed to 6 hours of cold ischemia (4°C), followed by 2 hours of warm (37°C) reperfusion with a solution containing 10% of fresh whole blood and mechanical ventilation with constant low driving pressure. Fas gene expression was significantly silenced at the level of messenger RNA and protein after ischemia-reperfusion in lungs treated with small interfering RNA targeting Fas compared with lungs treated with control small interfering RNA or vehicle. Silencing of Fas gene expression resulted in reduced edema formation (bronchoalveolar lavage protein concentration and lung histology) and improvement in lung compliance. These effects were associated with a significant reduction of pulmonary cell apoptosis of lungs treated with small interfering RNA targeting Fas, which did not affect cytokine release and neutrophil infiltration. Fas expression silencing in the lung by small interfering RNA is effective against ischemia-reperfusion injury. This approach represents a potential innovative strategy of organ preservation before lung transplantation.

Ocular blood flow decreases during passive heat stress in resting humans.

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Ikemura, Tsukasa; Miyaji, Akane; Kashima, Hideaki; Yamaguchi, Yuji; Hayashi, Naoyuki

2013-12-06

Heat stress induces various physiological changes and so could influence ocular circulation. This study examined the effect of heat stress on ocular blood flow. Ocular blood flow, end-tidal carbon dioxide (P(ET)CO2) and blood pressure were measured for 12 healthy subjects wearing water-perfused tube-lined suits under two conditions of water circulation: (1) at 35 °C (normothermia) for 30 min and (2) at 50 °C for 90 min (passive heat stress). The blood-flow velocities in the superior temporal retinal arteriole (STRA), superior nasal retinal arteriole (SNRA), and the retinal and choroidal vessels (RCV) were measured using laser-speckle flowgraphy. Blood flow in the STRA and SNRA was calculated from the integral of a cross-sectional map of blood velocity. PETCO2 was clamped at the normothermia level by adding 5% CO2 to the inspired gas. Passive heat stress had no effect on the subjects' blood pressures. The blood-flow velocity in the RCV was significantly lower after 30, 60 and 90 min of passive heat stress than the normothermic level, with a peak decrease of 18 ± 3% (mean ± SE) at 90 min. Blood flow in the STRA and SNRA decreased significantly after 90 min of passive heat stress conditions, with peak decreases of 14 ± 3% and 14 ± 4%, respectively. The findings of this study suggest that passive heat stress decreases ocular blood flow irrespective of the blood pressure or arterial partial pressure of CO2.

Effects of ebselen on ischemia/reperfusion injury in rat brain.

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Aras, M; Altaş, M; Meydan, S; Nacar, E; Karcıoğlu, M; Ulutaş, K T; Serarslan, Y

2014-10-01

Interruption of blood flow may result in considerable tissue damage via ischemia/reperfusion (I/R) injury-induced oxidative stress in brain tissues. The aim of the present study was to investigate the effects of Ebselen treatment in short-term global brain I/R injury in rats. The study was carried out on 27 Wistar-albino rats, divided into three groups including Sham group (n = 11), I/R group (n = 8) and I/R+Ebselen group (n = 8). Malondialdehyde (MDA) levels were significantly increased in I/R group in comparison with the Sham group and I/R+Ebselen group (p Ebselen (p Ebselen group when compared with Sham group (p Ebselen group when compared with Sham (p Ebselen showed morphological improvement. Ebselen has neuron-protective effects due to its antioxidant properties as shown by the decrease in MDA overproduction, increase in SOD activity and the histological improvement after administration of Ebselen to I/R in brain tissue.

Quantitative blood flow analysis with digital techniques

International Nuclear Information System (INIS)

Forbes, G.

1984-01-01

The general principles of digital techniques in quantitating absolute blood flow during arteriography are described. Results are presented for a phantom constructed to correlate digitally calculated absolute flow with direct flow measurements. The clinical use of digital techniques in cerebrovascular angiography is briefly described. (U.K.)

The Effect of Erythropoietin on Testosterone Levels During Ischemia Reperfusion Injury in Rats

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Tsompos C.

2016-11-01

Full Text Available Objective: This experimental study examined the effect of erythropoietin (Epo in a rat model and particularly in an adrenal ischemia-reperfusion (IR protocol. The effect of that molecule was studied biochemically using blood mean testosterone levels (T.

Supraorbital cutaneous blood flow rate during carotid endarterectomy

DEFF Research Database (Denmark)

Hove, Jens D; Rosenberg, Iben; Sejrsen, Per

2006-01-01

: The supraorbital cutaneous blood flow rate was measured by the application of heat to the skin and following the subsequent dissipation of the heat in seven patients undergoing carotid endarterectomy. At the same time, the oxygenation in the right and left frontal region was monitored by near-infrared spectroscopy......BACKGROUND: The supraorbital skin region is supplied by the supraorbital artery, which is a branch of the internal carotid artery. The supraorbital cutaneous blood flow rate may therefore be influenced by changes in the internal carotid artery flow during carotid endarterectomy. METHODS...... (NIRS). RESULTS: During cross-clamping of the carotid artery, the ipsilateral NIRS-determined frontal oxygenation tended to decrease [67 +/- 13% to 61 +/- 11% (P = 0.06); contralateral 68 +/- 11% to 66 +/- 8%] as did the supraorbital cutaneous blood flow rate from 56 +/- 23 to 44 +/- 7 ml 100 g(-1) min...

Intrinsic regulation of blood flow in adipose tissue

DEFF Research Database (Denmark)

Henriksen, O; Nielsen, Steen Levin; Paaske, W

1976-01-01

Previous studies on intact human subcutaneous tissue have shown, that blood flow remains constant during minor changes in perfusion pressure. This so-called autoregulatory response has not been demonstrable in isolated preparations of adipose tissue. In the present study on isolated, denervated...... subcutaneous tissue in female rabbits only 2 of 12 expts. revealed an autoregulatory response during reduction in arterial perfusion pressure. Effluent blood flow from the tissue in the control state was 15.5 ml/100 g-min (S.D. 6.4, n = 12) corresponding to slight vasodilatation of the exposed tissue...... vasoconstriction with pronounced flow reduction. These two reactions may be important for local regulation of blood flow in subcutaneous tissue during orthostatic changes in arterial and venous pressure. It is concluded that the response in adipose tissue to changes in arterial pressure (autoregulation), venous...

Blood flow patterns during incremental and steady-state aerobic exercise.

Science.gov (United States)

Coovert, Daniel; Evans, LeVisa D; Jarrett, Steven; Lima, Carla; Lima, Natalia; Gurovich, Alvaro N

2017-05-30

Endothelial shear stress (ESS) is a physiological stimulus for vascular homeostasis, highly dependent on blood flow patterns. Exercise-induced ESS might be beneficial on vascular health. However, it is unclear what type of ESS aerobic exercise (AX) produces. The aims of this study are to characterize exercise-induced blood flow patterns during incremental and steady-state AX. We expect blood flow pattern during exercise will be intensity-dependent and bidirectional. Six college-aged students (2 males and 4 females) were recruited to perform 2 exercise tests on cycleergometer. First, an 8-12-min incremental test (Test 1) where oxygen uptake (VO2), heart rate (HR), blood pressure (BP), and blood lactate (La) were measured at rest and after each 2-min step. Then, at least 48-hr. after the first test, a 3-step steady state exercise test (Test 2) was performed measuring VO2, HR, BP, and La. The three steps were performed at the following exercise intensities according to La: 0-2 mmol/L, 2-4 mmol/L, and 4-6 mmol/L. During both tests, blood flow patterns were determined by high-definition ultrasound and Doppler on the brachial artery. These measurements allowed to determine blood flow velocities and directions during exercise. On Test 1 VO2, HR, BP, La, and antegrade blood flow velocity significantly increased in an intensity-dependent manner (repeated measures ANOVA, pflow velocity did not significantly change during Test 1. On Test 2 all the previous variables significantly increased in an intensity-dependent manner (repeated measures ANOVA, pflow patterns during incremental and steady-state exercises include both antegrade and retrograde blood flows.

Coronary blood flow during cardiopulmonary resuscitation in swine

International Nuclear Information System (INIS)

Bellamy, R.F.; DeGuzman, L.R.; Pedersen, D.C.

1984-01-01

Recent papers have raised doubt as to the magnitude of coronary blood flow during closed-chest cardiopulmonary resuscitation. We will describe experiments that concern the methods of coronary flow measurement during cardiopulmonary resuscitation. Nine anesthetized swine were instrumented to allow simultaneous measurements of coronary blood flow by both electromagnetic cuff flow probes and by the radiomicrosphere technique. Cardiac arrest was caused by electrical fibrillation and closed-chest massage was performed by a Thumper (Dixie Medical Inc., Houston). The chest was compressed transversely at a rate of 66 strokes/min. Compression occupied one-half of the massage cycle. Three different Thumper piston strokes were studied: 1.5, 2, and 2.5 inches. Mean aortic pressure and total systemic blood flow measured by the radiomicrosphere technique increased as Thumper piston stroke was lengthened (mean +/- SD): 1.5 inch stroke, 23 +/- 4 mm Hg, 525 +/- 195 ml/min; 2 inch stroke, 33 +/- 5 mm Hg, 692 +/- 202 ml/min; 2.5 inch stroke, 40 +/- 6 mm Hg, 817 +/- 321 ml/min. Both methods of coronary flow measurement (electromagnetic [EMF] and radiomicrosphere [RMS]) gave similar results in technically successful preparations (data expressed as percent prearrest flow mean +/- 1 SD): 1.5 inch stroke, EMF 12 +/- 5%, RMS 16 +/- 5%; 2 inch stroke, EMF 30 +/- 6%, RMS 26 +/- 11%; 2.5 inch stroke, EMF 50 +/- 12%, RMS 40 +/- 20%. The phasic coronary flow signal during closed-chest compression indicated that all perfusion occurred during the relaxation phase of the massage cycle. We concluded that coronary blood flow is demonstrable during closed-chest massage, but that the magnitude is unlikely to be more than a fraction of normal

Influence of Dai-kenchu-to (DKT) on human portal blood flow.

Science.gov (United States)

Ogasawara, Takashi; Morine, Yuji; Ikemoto, Tetsuya; Imura, Satoru; Fujii, Masahiko; Soejima, Yuji; Shimada, Mitsuo

2008-01-01

Dai-kenchu-to (DKT) is known as an herbal medicine used for postoperative ileus. However, no report exists about the effect of DKT on portal blood flow. The aim of this study is to clarify the influence of DKT on portal blood flow. To healthy volunteers (Healthy; n = 6), cirrhotic patients (Cirrhosis; n = 7) and liver-transplant patients (LTx; n = 3), DKT (2.5g) with 100mL of warm water was orally administrated in the DKT group, and only warm water was administrated in the control group. The portal blood flow rate (M-VEL: cm/sec.) and portal blood flow (Flow volume: mL/min.) was measured each time after administration using an ultrasonic Doppler method. Furthermore, the arterial blood pressure and heart rate was measured at the same time points. In the DKT group, a significant increase of M-VEL (120%) and flow volume (150%) 30 minutes after administration was observed in both Healthy and Cirrhosis in comparison with the control group. In LTx, there was also a significant increase of flow volume (128%) 30 minutes after administration. However, there was no change in average blood pressure and heart rate in all groups. DKT increases portal blood flow in early phase after oral administration without any significant changes in the blood pressure and heart rate.

Detection of viable cortical neurons using benzodiazepine receptor imaging after reversible focal ischaemia in rats: comparison with regional cerebral blood flow

International Nuclear Information System (INIS)

Watanabe, Yoshiyuki; Nakano, Takayuki; Yutani, Kenji; Nishimura, Hiroshi; Nishimura, Tsunehiko; Kusuoka, Hideo; Nakamura, Hironobu

2000-01-01

To elucidate the utility of benzodiazepine receptor imaging for the detection of viable cortical neurons, dual-tracer autoradiography using iodine-125 iomazenil (IMZ) and iodine-123 N-isopropyl-4-iodoamphetamine (IMP) was performed in a model of reversible focal ischaemia during the acute and subacute phases. The right middle cerebral artery of anaesthetized rats was occluded for 60 min using an intraluminal filament and reperfused. In the acute phase study, 125 I-IMZ (370 kBq) was injected via the femoral vein at 2 h after reperfusion, and 123 I-IMP (37 MBq) was injected at 50 min post-injection. Rats were sacrificed 10 min after the injection of 123 I-IMP. In the subacute phase study, the same procedure was performed at 5 days after reperfusion. In the acute phase, the IMP uptake was significantly decreased in almost all areas of the lesioned hemisphere, an exception being the cerebellum; however, the IMZ uptake was significantly decreased only in ischaemic cores. The discrepancy between IMZ and IMP uptake was observed in the lateral neocortex and the lateral caudate putamen (CPu), which were most frequently damaged in this ischaemic model. In the subacute phase, the IMZ uptake in lesioned rats was significantly decreased only in the parietal lobe and hippocampus, though the IMP uptake was decreased in many regions of lesioned hemispheres (the frontal, parietal cortex, CPu, hippocampus and thalamus). Histopathological findings indicated that both the IMP and the IMZ uptake was markedly decreased in necrotic areas. Although the IMP uptake was significantly decreased in the ischaemic areas, the IMZ uptake was maintained in these areas. These results suggest that benzodiazepine receptor imaging is superior to regional cerebral blood flow imaging for the detection of viable cortical neurons in both the acute and subacute phases of ischaemia. (orig.)

Detection of viable cortical neurons using benzodiazepine receptor imaging after reversible focal ischaemia in rats: comparison with regional cerebral blood flow

Energy Technology Data Exchange (ETDEWEB)

Watanabe, Yoshiyuki [Dept. of Radiology, Osaka National Hospital (Japan); Nakano, Takayuki; Yutani, Kenji; Nishimura, Hiroshi; Nishimura, Tsunehiko [Div. of Tracer Kinetics, Osaka University Medical School (Japan); Kusuoka, Hideo [Clinical Research Institute, Osaka National Hospital (Japan); Nakamura, Hironobu [Dept. of Radiology, Osaka University Medical School (Japan)

2000-03-01

To elucidate the utility of benzodiazepine receptor imaging for the detection of viable cortical neurons, dual-tracer autoradiography using iodine-125 iomazenil (IMZ) and iodine-123 N-isopropyl-4-iodoamphetamine (IMP) was performed in a model of reversible focal ischaemia during the acute and subacute phases. The right middle cerebral artery of anaesthetized rats was occluded for 60 min using an intraluminal filament and reperfused. In the acute phase study, {sup 125}I-IMZ (370 kBq) was injected via the femoral vein at 2 h after reperfusion, and {sup 123}I-IMP (37 MBq) was injected at 50 min post-injection. Rats were sacrificed 10 min after the injection of {sup 123}I-IMP. In the subacute phase study, the same procedure was performed at 5 days after reperfusion. In the acute phase, the IMP uptake was significantly decreased in almost all areas of the lesioned hemisphere, an exception being the cerebellum; however, the IMZ uptake was significantly decreased only in ischaemic cores. The discrepancy between IMZ and IMP uptake was observed in the lateral neocortex and the lateral caudate putamen (CPu), which were most frequently damaged in this ischaemic model. In the subacute phase, the IMZ uptake in lesioned rats was significantly decreased only in the parietal lobe and hippocampus, though the IMP uptake was decreased in many regions of lesioned hemispheres (the frontal, parietal cortex, CPu, hippocampus and thalamus). Histopathological findings indicated that both the IMP and the IMZ uptake was markedly decreased in necrotic areas. Although the IMP uptake was significantly decreased in the ischaemic areas, the IMZ uptake was maintained in these areas. These results suggest that benzodiazepine receptor imaging is superior to regional cerebral blood flow imaging for the detection of viable cortical neurons in both the acute and subacute phases of ischaemia. (orig.)

Measurement of blood flow through surgical anastomosis using the radioactive microsphere technique

Energy Technology Data Exchange (ETDEWEB)

Hummel, S.J.; Delgado, G.; Butterfield, A.; Dritschilo, A.; Harbert, J.

1985-10-01

Two different radioactive microspheres ( U Ce and UWSc) were used to measure blood flow to an area of the large intestine in dogs before and after a surgical resection was performed with surgical staples. The healing of an anastomosis is theoretically related to the blood flow to the anastomotic site. Blood flow studies were conducted in three dogs using this technique. The average blood flow preoperatively was 0.558 mL/minute per gram and 1.04 mL/minute per gram postoperatively. These results indicate a statistically significant increase in blood flow at the anastomotic site six days after anastomosis when compared with the blood flow to the same area before any surgical procedures.

Measurement of blood flow through surgical anastomosis using the radioactive microsphere technique

International Nuclear Information System (INIS)

Hummel, S.J.; Delgado, G.; Butterfield, A.; Dritschilo, A.; Harbert, J.

1985-01-01

Two different radioactive microspheres ( 141 Ce and 46 Sc) were used to measure blood flow to an area of the large intestine in dogs before and after a surgical resection was performed with surgical staples. The healing of an anastomosis is theoretically related to the blood flow to the anastomotic site. Blood flow studies were conducted in three dogs using this technique. The average blood flow preoperatively was 0.558 mL/minute per gram and 1.04 mL/minute per gram postoperatively. These results indicate a statistically significant increase in blood flow at the anastomotic site six days after anastomosis when compared with the blood flow to the same area before any surgical procedures

Investigation of spiral blood flow in a model of arterial stenosis.

Science.gov (United States)

Paul, Manosh C; Larman, Arkaitz

2009-11-01

The spiral component of blood flow has both beneficial and detrimental effects in human circulatory system [Stonebridge PA, Brophy CM. Spiral laminar flow in arteries? Lancet 1991; 338: 1360-1]. We investigate the effects of the spiral blood flow in a model of three-dimensional arterial stenosis with a 75% cross-sectional area reduction at the centre by means of computational fluid dynamics (CFD) techniques. The standard k-omega model is employed for simulation of the blood flow for the Reynolds number of 500 and 1000. We find that for Re=500 the spiral component of the blood flow increases both the total pressure and velocity of the blood, and some significant differences are found between the wall shear stresses of the spiral and non-spiral induced flow downstream of the stenosis. The turbulent kinetic energy is reduced by the spiral flow as it induces the rotational stabilities in the forward flow. For Re=1000 the tangential component of the blood velocity is most influenced by the spiral speed, but the effect of the spiral flow on the centreline turbulent kinetic energy and shear stress is mild. The results of the effects of the spiral flow are discussed in the paper along with the relevant pathological issues.

Spatial Temporal Image Correlation Spectroscopy (STICS) for Flow Analysis with Application for Blood Flow Mapping (abstract)

Science.gov (United States)

Rossow, Molly; Mantulin, William M.; Gratton, Enrico

2009-04-01

It is important for surgeons to be able to measure blood flow in exposed arterioles during surgery. We report our progress in the development of an optical technique that will measure blood flow in surgically exposed blood vessels and enable previously difficult measurements. By monitoring optical fluctuations, the optical technique, based on Spatial Temporal Image Correlation (STICS), will directly measure the velocity of micron-scale particles-such as red blood cells. It will complement existing technology and provide qualitative measurements that were not previously possible. It relies on the concept that blood, when viewed on a small enough scale, is an inhomogeneous substance. Individual blood cells passing between a near-infrared light source and a detector will cause fluctuations in the transmitted optical signal. The speed, direction, and flow pattern of blood cells can be determined from these optical fluctuations. We present a series of computer simulations and experiments on phantom and animal systems to test this technique's ability to map complex flow patterns.

Effect of warming and flow rate conditions of blood warmers on red blood cell integrity.

Science.gov (United States)

Poder, T G; Pruneau, D; Dorval, J; Thibault, L; Fisette, J-F; Bédard, S K; Jacques, A; Beauregard, P

2016-11-01

Fluid warmers are routinely used to reduce the risk of hypothermia and cardiac complications associated with the infusion of cold blood products. However, warming blood products could generate haemolysis. This study was undertaken to compare the impact of temperature of blood warmers on the per cent haemolysis of packed red blood cells (RBCs) heated at different flow rates as well as non-flow conditions. Infusion warmers used were calibrated at 41·5°C ± 0·5°C and 37·5°C ± 0·5°C. Cold RBC units stored at 4°C in AS-3 (n = 30), aged 30-39 days old, were divided into half units before being allocated under two different scenarios (i.e. infusion pump or syringe). Blood warmers were effective to warm cold RBCs to 37·5°C or 41·5°C when used in conjunction with an infusion pump at flow rate up to 600 ml/h. However, when the warmed blood was held in a syringe for various periods of time, such as may occur in neonatal transfusions, the final temperature was below the expected requirements with measurement as low as 33·1°C. Increasing the flow with an infusion pump increased haemolysis in RBCs from 0·2% to up to 2·1% at a flow rate of 600 ml/h regardless of the warming device used (P < 0·05). No relevant increase of haemolysis was observed using a syringe. The use of a blood warmer adjusted to 41·5°C is probably the best choice for reducing the risk of hypothermia for the patient without generating haemolysis. However, we should be cautious with the use of an infusion pump for RBC transfusion, particularly at high flow rates. © 2016 International Society of Blood Transfusion.

Polydeoxyribonucleotides and nitric oxide release from guinea-pig hearts during ischaemia and reperfusion.

Science.gov (United States)

Masini, E.; Lupini, M.; Mugnai, L.; Raspanti, S.; Mannaioni, P. F.

1995-01-01

1. Two polydeoxyribonucleotides, produced by the controlled hydrolysis of DNA of mammalian lung (defibrotide and its lower molecular weight fraction, P.O. 085 DV), were studied for their ability to modify the release of nitrite and the coronary flow in perfusates collected from isolated, normally perfused hearts of guinea-pigs and from hearts subjected to regional ischaemia and reperfusion. 2. In guinea-pig normally perfused hearts, both defibrotide (DFT) and its fraction, P.O. 085 DV, increase the amount of nitrite appearing in perfusates in a concentration-dependent fashion. At the highest concentration studied (10(-6) M), P.O. 085 DV was more effective than DFT. A concomitant increase in the coronary flow was observed. 3. The increase in nitrite in perfusates and the increase in coronary flow induced by both DFT and P.O. 085 DV were significantly reduced by NG-monomethyl-L-arginine (L-NMMA, 10(-4) M), an inhibitor of nitric oxide synthase (NOS). 4. The endothelium-dependent vasodilator, acetylcholine (ACh), enhances the formation of nitrite and the coronary flow. Both the increase in coronary flow and in the formation of nitrite were significantly reduced by L-NMMA (10(-4) M). 5. In guinea-pig hearts subjected to ischaemia and reperfusion, the effect of both compounds in increasing the amount of nitrite in perfusates was more evident and more pronounced with P.O. 085 DV. 6. Reperfusion-induced arrhythmias were significantly reduced by both compounds to the extent of complete protection afforded by compound P.O. 085 DV. 7. The cardioprotective and antiarrhythmic effects of DFT and P.O. 085 DV are discussed. PMID:7582482

Placental blood flow measurements with radioisotopes in the pregnant guinea pig

International Nuclear Information System (INIS)

Schmitt, R.; Giese, W.; Kurz, C.S.; Kuenzel, W.

1976-01-01

In 15 pregnant guinea pigs near term the blood flow (BF) of the myometrium and the placenta as well as the cardiac output were measured with 99 Tcsup(m)-labelled microspheres. In front of one placenta the clearance of 133 Xe was estimated in the same animal. For the 133 Xe measurement a theoretical concept is presented. The mean placental BF is 105ml/(minx100g)(SD:84) for 99 Tcsup(m) and 244(SD:80)ml/(minx100g) for 133 Xe. The difference in both flow values is assumed to be related to foetal placental BF. The placental blood flow is also related to the location of the placenta in the uterine horn. The ratio of myometrial blood flow to placental blood flow decreased with an increase in the mean arterial blood pressure. The measurements are a preliminary report of an attempt to compare two different methods in measuring placental blood flow. (author)

Effects of Chronic and Acute Zinc Supplementation on Myocardial Ischemia-Reperfusion Injury in Rats.

Science.gov (United States)

Ozyıldırım, Serhan; Baltaci, Abdulkerim Kasim; Sahna, Engin; Mogulkoc, Rasim

2017-07-01

The present study aims to explore the effects of chronic and acute zinc sulfate supplementation on myocardial ischemia-reperfusion injury in rats. The study registered 50 adult male rats which were divided into five groups in equal numbers as follows: group 1, normal control; group 2, sham; group 3, myocardial ischemia reperfusion (My/IR): the group which was fed on a normal diet and in which myocardial I/R was induced; group 4, myocardial ischemia reperfusion + chronic zinc: (5 mg/kg i.p. zinc sulfate for 15 days); and group 5, myocardial ischemia reperfusion + acute zinc: the group which was administered 15 mg/kg i.p. zinc sulfate an hour before the operation and in which myocardial I/R was induced. The collected blood and cardiac tissue samples were analyzed using spectrophotometric method to determine levels of MDA, as an indicator of tissue injury, and GSH, as an indicator of antioxidant activity. The highest plasma and heart tissue MDA levels were measured in group 3 (p zinc administration and markedly by chronic zinc supplementation.

Capillary pericytes regulate cerebral blood flow in health and disease

DEFF Research Database (Denmark)

Hall, Catherine N; Reynell, Clare; Gesslein, Bodil

2014-01-01

Increases in brain blood flow, evoked by neuronal activity, power neural computation and form the basis of BOLD (blood-oxygen-level-dependent) functional imaging. Whether blood flow is controlled solely by arteriole smooth muscle, or also by capillary pericytes, is controversial. We demonstrate t...

Inner ocular blood flow responses to an acute decrease in blood pressure in resting humans

International Nuclear Information System (INIS)

Ikemura, Tsukasa; Kashima, Hideaki; Yamaguchi, Yuji; Miyaji, Akane; Hayashi, Naoyuki

2015-01-01

Whether inner ocular vessels have an autoregulatory response to acute fluctuations in blood pressure is unclear. We tried to examine the validity of acute hypotension elicited by thigh-cuff release as to assess the dynamic autoregulation in the ocular circulation. Blood flow velocity in the superior nasal and inferior temporal retinal arterioles, and in the retinal and choroidal vasculature were measured with the aid of laser speckle flowgraphy before and immediately after an acute decrease in blood pressure in 20 healthy subjects. Acute hypotension was induced by a rapid release of bilateral thigh occlusion cuffs that had been inflated to 220 mmHg for 2 min. The ratio of the relative change in retinal and choroidal blood flow velocity to the relative change in mean arterial blood pressure (MAP) was calculated. Immediately after cuff release, the MAP and blood flows in the all ocular target vessels decreased significantly from the baseline values obtained before thigh-cuff release. The ratio of the relative change in inner ocular blood flow velocity to that in the MAP exceeded 1% / %mmHg. An explicit dynamic autoregulation in inner ocular vessels cannot be demonstrated in response to an acute hypotension induced by the thigh-cuff release technique. (paper)

Modeling cerebral blood flow during posture change from sitting to standing

DEFF Research Database (Denmark)

Ottesen, Johnny T.; Olufsen, M.; Tran, H.T.

2004-01-01

extremities, the brain, and the heart. We use physiologically based control mechanisms to describe the regulation of cerebral blood flow velocity and arterial pressure in response to orthostatic hypotension resulting from postural change. To justify the fidelity of our mathematical model and control......Abstract Hypertension, decreased cerebral blood flow, and diminished cerebral blood flow velocity regulation, are among the first signs indicating the presence of cerebral vascular disease. In this paper, we will present a mathematical model that can predict blood flow and pressure during posture...

Hemorheological and metabolic consequences of renal ischemia-reperfusion and their modulation by N,N-dimethyl-tryptamine on a rat model.

Science.gov (United States)

Peto, Katalin; Nemeth, Norbert; Mester, Anita; Magyar, Zsuzsanna; Ghanem, Souleiman; Somogyi, Viktoria; Tanczos, Bence; Deak, Adam; Bidiga, Laszlo; Frecska, Ede; Nemes, Balazs

2018-04-13

Micro-rheological relations of renal ischemia-reperfusion (I/R) have not been completely elucidated yet. Concerning anti-inflammatory agents, it is supposed that sigma-1 receptor agonist N,N-dimethyl-tryptamin (DMT) can be useful to reduce I/R injury. To investigate the micro-rheological and metabolic parameters, and the effects of DMT in renal I/R in rats. In anesthetized rats from median laparotomy both kidneys were exposed. In Control group (n = 6) no other intervention happened. In I/R group (n = 10) the right renal vessels were ligated and after 60 minutes the organ was removed. The left renal vessels were clamped for 60 minutes followed by 120-minute reperfusion. In I/R+DMT group (n = 10) DMT was administered 15 minutes before the ischemia. Blood samples were taken before/after ischemia and during the reperfusion for testing hematological, metabolic parameters, erythrocyte deformability and aggregation. Lactate concentration significantly increased and accompanied with decreased blood pH. Enhanced erythrocyte aggregation and impaired deformability were observed from the 30th minute of reperfusion. In I/R+DMT group we found diminished changes compared to the I/R group (lactate, pH, electrolytes, red blood cell deformability and aggregation). Metabolic and micro-rheological parameters impair during renal I/R. DMT could reduce but not completely prevent the changes in this rat model.

Cerebral blood-flow tomography

DEFF Research Database (Denmark)

Lassen, N A; Henriksen, L; Holm, S

1983-01-01

. The Xe-133 flow maps are essentially based on the average Xe-133 concentration over the initial 2 min during and after an inhalation of the inert gas lasting 1 min. These maps agreed very well with the early IMP maps obtained over the initial 10 min following an i.v. bolus injection. The subsequent IMP......, and with low radiation exposure to patient and personnel. On the other hand, IMP gives an image of slightly higher resolution. It also introduces a new class of iodinated brain-seeking compounds allowing, perhaps, imaging of other functions more important than mere blood flow....

Positron emission tomography detects greater blood flow and less blood flow heterogeneity in the exercising skeletal muscles of old compared with young men during fatiguing contractions

Science.gov (United States)

Rudroff, Thorsten; Weissman, Jessica A; Bucci, Marco; Seppänen, Marko; Kaskinoro, Kimmo; Heinonen, Ilkka; Kalliokoski, Kari K

2014-01-01

The purpose of this study was to investigate blood flow and its heterogeneity within and among the knee muscles in five young (26 ± 6 years) and five old (77 ± 6 years) healthy men with similar levels of physical activity while they performed two types of submaximal fatiguing isometric contraction that required either force or position control. Positron emission tomography (PET) and [15O]-H2O were used to determine blood flow at 2 min (beginning) and 12 min (end) after the start of the tasks. Young and old men had similar maximal forces and endurance times for the fatiguing tasks. Although muscle volumes were lower in the older subjects, total muscle blood flow was similar in both groups (young men: 25.8 ± 12.6 ml min−1; old men: 25.1 ± 15.4 ml min−1; age main effect, P = 0.77) as blood flow per unit mass of muscle in the exercising knee extensors was greater in the older (12.5 ± 6.2 ml min−1 (100 g)−1) than the younger (8.6 ± 3.6 ml min−1 (100 g)−1) men (age main effect, P = 0.001). Further, blood flow heterogeneity in the exercising knee extensors was significantly lower in the older (56 ± 27%) than the younger (67 ± 34%) men. Together, these data show that although skeletal muscles are smaller in older subjects, based on the intact neural drive to the muscle and the greater, less heterogeneous blood flow per gram of muscle, old fit muscle achieves adequate exercise hyperaemia. Key points The results of previous studies that attempted to demonstrate the effects of ageing on skeletal muscle blood flow are controversial because these studies used indirect assessments of skeletal muscle blood flow obtained via whole limb blood flow measurements that provide no information on the distribution of blood flow within particular muscles. We used positron emission tomography to measure blood flow per gram of muscle in old and young men with similar levels of physical activity

Effective RES blood flow changes in children with homozygous β-thalassemia in relation to blood transfusion

International Nuclear Information System (INIS)

Karpathios, T.; Dimitriou, P.; Giamouris, J.; Nicolaidou, P.; Antipas, S.E.; Matsaniotis, N.

1983-01-01

Denatured radioiodinated human serum albumin (DHA) clearance studies at a dose of 1 mg/kg body wt., were carried out in 16 thalassemic children, prior to and 7-10 days following blood transfusion, to investigate changes of the effective RES blood flow which might accompany the posttransfusion spleen size diminution. A statistically significant increase (P<0.001) of the DHA plasma clearance rate was observed 7-10 days following blood transfusion denoting an increase of the blood flow to the effective RES while at the same time the spleen diminished in size. It is suggested that changes in the effective RES blood flow in these patients are directly related to changes in the intrasplenic circulatory capacity. (orig.)

Ocular Blood Flow and Normal Tension Glaucoma

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Ning Fan

2015-01-01

Full Text Available Normal tension glaucoma (NTG is known as a multifactorial optic neuropathy characterized by progressive retinal ganglion cell death and glaucomatous visual field loss, even though the intraocular pressure (IOP does not exceed the normal range. The pathophysiology of NTG remains largely undetermined. It is hypothesized that the abnormal ocular blood flow is involved in the pathogenesis of this disease. A number of evidences suggested that the vascular factors played a significant role in the development of NTG. In recent years, the new imaging techniques, fluorescein angiography, color Doppler imaging (CDI, magnetic resonance imaging (MRI, and laser speckle flowgraphy (LSFG, have been used to evaluate the ocular blood flow and blood vessels, and the impaired vascular autoregulation was found in patients with NTG. Previous studies showed that NTG was associated with a variety of systemic diseases, including migraine, Alzheimer’s disease, primary vascular dysregulation, and Flammer syndrome. The vascular factors were involved in these diseases. The mechanisms underlying the abnormal ocular blood flow in NTG are still not clear, but the risk factors for glaucomatous optic neuropathy likely included oxidative stress, vasospasm, and endothelial dysfunction.

Establishing the diffuse correlation spectroscopy signal relationship with blood flow.

Science.gov (United States)

Boas, David A; Sakadžić, Sava; Selb, Juliette; Farzam, Parisa; Franceschini, Maria Angela; Carp, Stefan A

2016-07-01

Diffuse correlation spectroscopy (DCS) measurements of blood flow rely on the sensitivity of the temporal autocorrelation function of diffusively scattered light to red blood cell (RBC) mean square displacement (MSD). For RBCs flowing with convective velocity [Formula: see text], the autocorrelation is expected to decay exponentially with [Formula: see text], where [Formula: see text] is the delay time. RBCs also experience shear-induced diffusion with a diffusion coefficient [Formula: see text] and an MSD of [Formula: see text]. Surprisingly, experimental data primarily reflect diffusive behavior. To provide quantitative estimates of the relative contributions of convective and diffusive movements, we performed Monte Carlo simulations of light scattering through tissue of varying vessel densities. We assumed laminar vessel flow profiles and accounted for shear-induced diffusion effects. In agreement with experimental data, we found that diffusive motion dominates the correlation decay for typical DCS measurement parameters. Furthermore, our model offers a quantitative relationship between the RBC diffusion coefficient and absolute tissue blood flow. We thus offer, for the first time, theoretical support for the empirically accepted ability of the DCS blood flow index ([Formula: see text]) to quantify tissue perfusion. We find [Formula: see text] to be linearly proportional to blood flow, but with a proportionality modulated by the hemoglobin concentration and the average blood vessel diameter.

Regulation of bone blood flow in humans

DEFF Research Database (Denmark)

Heinonen, Ilkka; Boushel, Robert; Hellsten, Ylva

2018-01-01

of cyclooxygenase (COX) enzyme, thus prostaglandin (PG) synthesis on femoral bone marrow blood flow by positron emission tomography in healthy young men at rest and during one leg dynamic exercise. In an additional group of healthy men, the role of adenosine (ADO) in the regulation of BBF during exercise......The mechanisms that regulate bone blood flow (BBF) in humans are largely unknown. Animal studies suggest that nitric oxide (NO) could be involved and in the present study we investigated the effects of inhibition of nitric oxide synthase (NOS) alone and in combination with inhibition.......036), but did not affect BBF significantly during exercise (5.5±1.4 ml/100g/min, p=0.25). On the other hand, while combined NOS and COX inhibition did not cause any further reduction of blood flow at rest (0.6±0.2 ml/100g/min), the combined blockade reduced BBF during exercise by ~21%, to 5.0±1.8 ml/100g/min (p...

Intraneural blood flow analysis during an intraoperative Phalen's test in carpal tunnel syndrome.

Science.gov (United States)

Yayama, Takafumi; Kobayashi, Shigeru; Awara, Kousuke; Takeno, Kenichi; Miyazaki, Tsuyoshi; Kubota, Masafumi; Negoro, Kohei; Baba, Hisatoshi

2010-08-01

Phalen's test has been one of the most significant of clinical signs when making a clinical diagnosis of idiopathic carpal tunnel syndrome (CTS). However, it is unknown whether intraneural blood flow changes during Phalen's test in patients with CTS. In this study, an intraoperative Phalen's test was conducted in patients with CTS to observe the changes in intraneural blood flow using a laser Doppler flow meter. During Phalen's test, intraneural blood flow showed a sharp decrease, which lasted for 1 min. Intraneural blood flow decreased by 56.7%-100% (average, 78.0%) in the median nerve relative to the blood flow before the test. At 1 min after completing the test, intraneural blood flow returned to the baseline value. After carpal tunnel release, there was no marked decrease in intraneural blood flow. This study demonstrated that the blood flow in the median nerve is reduced when Phalen's test is performed in vivo. Copyright 2010 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

Regulation of Blood Flow in Contracting Skeletal Muscle in Aging

DEFF Research Database (Denmark)

Piil, Peter Bergmann

Oxygen delivery to skeletal muscle is regulated precisely to match the oxygen demand; however, with aging the regulation of oxygen delivery during exercise is impaired. The present thesis investigated mechanisms underlying the age-related impairment in regulation of blood flow and oxygen delivery......GMP) was used as intervention, and skeletal muscle blood flow, oxygen delivery, and functional sympatholysis was examined. The two studies included 53 healthy, habitually active, male subjects. All subjects participated in an experimental day in which femoral arterial blood flow and blood pressure were assessed...... that improving sympatholytic capacity by training may be a slower process in older than in young men. In conclusion, this thesis provides new important knowledge related to the regulation of skeletal muscle blood flow in aging. Specifically, it demonstrates that changes in cGMP signaling is an underlying cause...

Blood in the gastric lumen increases splanchnic blood flow and portal pressure in portal-hypertensive rats.

Science.gov (United States)

Chen, L; Groszmann, R J

1996-10-01

In portal-hypertensive humans, portal blood flow and pressure increase after a meal. These hemodynamic changes may increase variceal rupture risk. The aim of this study was to determine whether blood in the stomach lumen increases splanchnic flow and portal pressure (PP) in portal-hypertensive rats. superior mesenteric artery flow and PP were measured in conscious, unrestrained, fasted partial portal vein-ligated rats with chronically implanted Doppler flow probes or portal vein catheters before and after gavage with heparinized, warmed blood from donor rats, air, standard meal, or empty tube. Percentage of changes in flow and pressure from baseline were significantly greater after gavage with blood (an increase of 22.6% +/- 3.5% and an increase of 16.4% +/- 3.1%, respectively) than empty tube (an increase of 3.4% +/- 0.6% and a decrease of 5.4% +/- 3.5%, respectively) (P empty tube (P calories probably contributes to these hemodynamic changes. In patients with variceal hemorrhage, blood in the stomach may increase the risk of persistent variceal bleeding or rebleeding.

Blood pressure and blood flow variation during postural change from sitting to standing: model development and validation

DEFF Research Database (Denmark)

Olufsen, M.S.; Ottesen, Johnny T.; Tran, H.T.

2005-01-01

Short-term cardiovascular responses to postural change from sitting to standing involve complex interactions between the autonomic nervous system, which regulates blood pressure, and cerebral autoregulation, which maintains cerebral perfusion. We present a mathematical model that can predict...... dynamic changes in beat-to-beat arterial blood pressure and middle cerebral artery blood flow velocity during postural change from sitting to standing. Our cardiovascular model utilizes 11 compartments to describe blood pressure, blood flow, compliance, and resistance in the heart and systemic circulation....... To include dynamics due to the pulsatile nature of blood pressure and blood flow, resistances in the large systemic arteries are modeled using nonlinear functions of pressure. A physiologically based submodel is used to describe effects of gravity on venous blood pooling during postural change. Two types...

Simple technique for measuring relative renal blood flow

International Nuclear Information System (INIS)

Shames, D.M.; Korobkin, M.

1976-01-01

To determine whether externally monitored early renal uptake of 131 I-hippurate is proportional to renal blood flow, the renal uptake of 131 -hippurate at 1 to 2 min after injection was compared with the renal accumulation of radioactive carbonized microspheres in dogs. A renal artery catheter equipped with a balloon was used to decrease renal blood flow unilaterally. One minute after the intravenous injection of 100 μCi of 131 I-hippurate, about 1 μCi of either 85 Sr- or 95 Nb-labeled carbon microspheres was injected into the left ventricle. Radioactivity was measured over both kidneys. The total radioactivity within each kidney region of interest was corrected for background and integrated over the 1 to 2 min interval after injection. Thirteen measurements of relative renal blood flow were made for seven dogs. The dogs were then killed and both kidneys were excised and counted for the radioactivity of the microspheres. The 1 to 2-min relative renal uptake of 131 I-hippurate correlated well with relative microsphere uptake, suggesting that relative renal blood flow can be simply determined from the external measurements of renal uptake of 131 I-hippurate

Radionuclide study on hepatic blood flow in Schistosomiasis Japonica

Energy Technology Data Exchange (ETDEWEB)

Okada, Junichi; Uchiyama, Guio; Hayakawa, Kazushige; Hayashi, Sanshin; Araki, Tsutomu; Arai, Takao; Iuchi, Masahiko

1986-11-01

Schistosomiasis Japonica is a regional disease found in elderly people who were living in once-endemic areas in Japan. Yamanashi was one of these areas until 1970, since when no newly infected patients were reported. The disease is characteristic of developing irreversible interstitial fibrosis of the liver, where parasites migrate and lay eggs. Portal hypertension, esophageal varices and hepatocellular carcinomas are the common features of the results. In order to estimate patient's hepatic blood flow, radionuclide angiography of the liver with the use of 10 - 15 millicuries of Tc-99m phytate were performed prior to the conventional multiview imaging. Twenty-two patients with schistosomiasis and twelve adults without evidence of liver disease were studied. A time-activity curve of the right lobe of the liver was generated by a computer, and the ratio of arterial blood flow to portal blood flow was calculated. As a result, a good correlation was found between the arterial to portal blood flow ratio and the grade of hepatic fibrosis verified by laparoscopic biopsy. The development of esophageal varices were likely to correlate well with the blood flow ratio rather than scores on the conventional static liver and spleen scintigram. The study was useful for evaluating patient's clinical stages and prognosis.

Radionuclide study on hepatic blood flow in Schistosomiasis Japonica

International Nuclear Information System (INIS)

Okada, Junichi; Uchiyama, Guio; Hayakawa, Kazushige; Hayashi, Sanshin; Araki, Tsutomu; Arai, Takao; Iuchi, Masahiko.

1986-01-01

Schistosomiasis Japonica is a regional disease found in elderly people who were living in once-endemic areas in Japan. Yamanashi was one of these areas until 1970, since when no newly infected patients were reported. The disease is characteristic of developing irreversible interstitial fibrosis of the liver, where parasites migrate and lay eggs. Portal hypertension, esophageal varices and hepatocellular carcinomas are the common features of the results. In order to estimate patient's hepatic blood flow, radionuclide angiography of the liver with the use of 10 - 15 millicuries of Tc-99m phytate were performed prior to the conventional multiview imaging. Twenty-two patients with schistosomiasis and twelve adults without evidence of liver disease were studied. A time-activity curve of the right lobe of the liver was generated by a computer, and the ratio of arterial blood flow to portal blood flow was calculated. As a result, a good correlation was found between the arterial to portal blood flow ratio and the grade of hepatic fibrosis verified by laparoscopic biopsy. The development of esophageal varices were likely to correlate well with the blood flow ratio rather than scores on the conventional static liver and spleen scintigram. The study was useful for evaluating patient's clinical stages and prognosis. (author)

Effects of respiratory muscle work on respiratory and locomotor blood flow during exercise.

Science.gov (United States)

Dominelli, Paolo B; Archiza, Bruno; Ramsook, Andrew H; Mitchell, Reid A; Peters, Carli M; Molgat-Seon, Yannick; Henderson, William R; Koehle, Michael S; Boushel, Robert; Sheel, A William

2017-11-01

What is the central question of this study? Does manipulation of the work of breathing during high-intensity exercise alter respiratory and locomotor muscle blood flow? What is the main finding and its importance? We found that when the work of breathing was reduced during exercise, respiratory muscle blood flow decreased, while locomotor muscle blood flow increased. Conversely, when the work of breathing was increased, respiratory muscle blood flow increased, while locomotor muscle blood flow decreased. Our findings support the theory of a competitive relationship between locomotor and respiratory muscles during intense exercise. Manipulation of the work of breathing (WOB) during near-maximal exercise influences leg blood flow, but the effects on respiratory muscle blood flow are equivocal. We sought to assess leg and respiratory muscle blood flow simultaneously during intense exercise while manipulating WOB. Our hypotheses were as follows: (i) increasing the WOB would increase respiratory muscle blood flow and decrease leg blood flow; and (ii) decreasing the WOB would decrease respiratory muscle blood flow and increase leg blood flow. Eight healthy subjects (n = 5 men, n = 3 women) performed a maximal cycle test (day 1) and a series of constant-load exercise trials at 90% of peak work rate (day 2). On day 2, WOB was assessed with oesophageal balloon catheters and was increased (via resistors), decreased (via proportional assist ventilation) or unchanged (control) during the trials. Blood flow was assessed using near-infrared spectroscopy optodes placed over quadriceps and the sternocleidomastoid muscles, coupled with a venous Indocyanine Green dye injection. Changes in WOB were significantly and positively related to changes in respiratory muscle blood flow (r = 0.73), whereby increasing the WOB increased blood flow. Conversely, changes in WOB were significantly and inversely related to changes in locomotor blood flow (r = 0.57), whereby decreasing the

Regional cerebral blood flow in focal cortical epilepsy

DEFF Research Database (Denmark)

Hougaard, Kristina Dupont; Oikawa, T; Sveinsdottir, E

1976-01-01

Regional cerebral blood flow (rCBF) was studied in ten patients with focal cortical epilepsy. The blood flow was measured by the intra-arterial injection of xenon 133 (133Xe), and the isotope clearance was recorded by a multidetector scintillation camera with 254 detectors. Three patients were....... This finding accords with earlier studies. All nine patients studied in the interictal phase showed, either spontaneously or during activation by intermittent light, focal flow increases in areas presumed to comprise the epileptic focus. These interictal hyperemic foci probably reflect subictal neuronal...

Concomitant administration of nitrous oxide and remifentanil reduces oral tissue blood flow without decreasing blood pressure during sevoflurane anesthesia in rabbits.

Science.gov (United States)

Kasahara, Masataka; Ichinohe, Tatsuya; Okamoto, Sota; Okada, Reina; Kanbe, Hiroaki; Matsuura, Nobuyuki

2015-06-01

To determine whether continuous administration of nitrous oxide and remifentanil—either alone or together—alters blood flow in oral tissues during sevoflurane anesthesia. Eight male tracheotomized Japanese white rabbits were anesthetized with sevoflurane under mechanical ventilation. Heart rate (HR), systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP), common carotid arterial blood flow (CCBF), tongue mucosal blood flow (TMBF), mandibular bone marrow blood flow (BBF), masseter muscle blood flow (MBF), upper alveolar tissue blood flow (UBF), and lower alveolar tissue blood flow (LBF) were recorded in the absence of all test agents and after administration of the test agents (50 % nitrous oxide, 0.4 μg/kg/min remifentanil, and their combination) for 20 min. Nitrous oxide increased SBP, DBP, MAP, CCBF, BBF, MBF, UBF, and LBF relative to baseline values but did not affect HR or TMBF. Remifentanil decreased all hemodynamic variables except DBP. Combined administration of nitrous oxide and remifentanil recovered SBP, DBP, MAP, and CCBF to baseline levels, but HR and oral tissue blood flow remained lower than control values. Our findings suggest that concomitant administration of nitrous oxide and remifentanil reduces blood flow in oral tissues without decreasing blood pressure during sevoflurane anesthesia in rabbits.

Measurement of regional cerebral blood flow by xenon-enhanced computed tomography

International Nuclear Information System (INIS)

Nakagomi, Tadayoshi; Yoshimasu, Norio; Kim, Shi-in; Takano, Koichi; Segawa, Hiromu.

1982-01-01

Serial CT scanning was carried out during and after inhalation of 50% non-radioactive xenon in humans. Our results of this research was as follows; 1) In normal subjects, blood flow in gray matter was 82 +- 11 and that in white matter 24 +- 5 ml/100 gm/min. 2) The blood flow of the brain tumors was close to that of gray matter, whereas blood flow of edematous white matter surrounding the tumor was decreased. 3) The blood flow in cerebral infarctions was always decreased. Effect of STA-MCA bypass was also evaluated. 4) In cerebral arterio-venous malformations, the blood flow in the white matter surrounding nidus was not decreased. This method appeared to have several advantages over conventional isotope method and to provide useful clinical and research informations. (author)

Regional cerebral blood flow characteristics of the Sturge-Weber syndrome

International Nuclear Information System (INIS)

Riela, A.R.; Stump, D.A.; Roach, E.S.; McLean, W.T. Jr.; Garcia, J.C.

1985-01-01

Four patients with the Sturge-Weber syndrome were studied using the non-invasive Xenon-133 inhalation technique. All four patients had decreased regional cerebral blood flow in the area of their lesion, and in two patients who were subsequently tested with 5% carbon dioxide inhalation, impaired vasomotor reactivity was documented. Diminished regional cerebral blood flow is consistent with previously described nuclide flow studies which demonstrated a delay in the initial perfusion blush in the region of the abnormal vasculature. The focal decrease in blood flow was greatest in the most severely affected patient, but was also prominent in the two younger patients, both of whom have excellent neurologic function. These studies suggest that localized decrease in blood flow and vasomotor dysfunction in Sturge-Weber syndrome can precede the occurrence of severe neurologic impairment and extensive cerebral atrophy and possibly be a major contributing factor in progressive dysfunction. A secondary observation was that the blood flow in the unaffected hemisphere was significantly greater in two children compared to the two adults and was similar to the age-related differences reported for normal children and adults

Skeletal blood flow: implications for bone-scan interpretation

International Nuclear Information System (INIS)

Charkes, N.D.

1980-01-01

The dispersion of the skeleton throughout the body and its complex vascular anatomy require indirect methods for the measurement of skeletal blood flow. The results of one such method, compartmental analysis of skeletal tracer kinetics, are presented. The assumptions underlying the models were tested in animals and found to be in agreement with experimental observations. Based upon the models and the experimental results, inferences concerning bone-scan interpretation can be drawn: decreased cardiac output produces low-contrast (technically poor) scans; decreased skeletal flow produces photon-deficient lesions; increase of cardiac output or of generalized systemic blood flow is undetectable 1 to 2 h after dose; increased local skeletal blood flow results from disturbance of the bone microvasculature and can occur from neurologic (sympatholytic) disorders or in association with focal abnormalities that also incite the formation of reactive bone (e.g., metastasis, fracture, etc.). Mathematical solutions of tracer kinetic data thus become relevant to bone-scan interpretation

Myocardial capillary permeability after regional ischemia and reperfusion in the in vivo canine heart. Effect of superoxide dismutase

DEFF Research Database (Denmark)

Svendsen, Jesper Hastrup; Bjerrum, P J; Haunsø, S

1991-01-01

coronary artery followed by 1 hour of reperfusion. Myocardial plasma flow rate and capillary extraction of chromium 51-labeled EDTA or technetium 99m-labeled diethylenetriaminepentaacetic acid were measured by the single-injection, residue-detection method before ischemia and 5 and 60 minutes after...... fibrillation in contrast to none in the superoxide dismutase group. Before ischemia, plasma flow rate, myocardial capillary extraction fraction, and PS values were similar in the two groups. Five minutes after the start of reperfusion, plasma flow rate increased significantly (p less than 0.01) in both groups....... In the control group, capillary extraction fraction increased by 12% (p = NS) in spite of the higher plasma flow; these increases in capillary extraction fraction and plasma flow induced a 69% increase in PS (p less than 0.01). In the superoxide dismutase-treated group, capillary extraction fraction decreased...

Noninvasive measurement of an index of renal blood flow

International Nuclear Information System (INIS)

Powers, T.A.; Rees, R.S.; Bowen, R.D.

1983-01-01

A new technique for the noninvasive measurement of an index of renal blood flow is described. The method utilizes ultrasound determined renal volume and radionuclide assessment of the mean transit time of a pertechnetate bolus through the kidneys. From this information a value for flow is calculated according to compartmental analysis principles. There is good correlation between renal blood flow estimated by this technique and that determined by microsphere injection

Numerical Modeling of Interstitial Fluid Flow Coupled with Blood Flow through a Remodeled Solid Tumor Microvascular Network.

Science.gov (United States)

Soltani, M; Chen, P

2013-01-01

Modeling of interstitial fluid flow involves processes such as fluid diffusion, convective transport in extracellular matrix, and extravasation from blood vessels. To date, majority of microvascular flow modeling has been done at different levels and scales mostly on simple tumor shapes with their capillaries. However, with our proposed numerical model, more complex and realistic tumor shapes and capillary networks can be studied. Both blood flow through a capillary network, which is induced by a solid tumor, and fluid flow in tumor's surrounding tissue are formulated. First, governing equations of angiogenesis are implemented to specify the different domains for the network and interstitium. Then, governing equations for flow modeling are introduced for different domains. The conservation laws for mass and momentum (including continuity equation, Darcy's law for tissue, and simplified Navier-Stokes equation for blood flow through capillaries) are used for simulating interstitial and intravascular flows and Starling's law is used for closing this system of equations and coupling the intravascular and extravascular flows. This is the first study of flow modeling in solid tumors to naturalistically couple intravascular and extravascular flow through a network. This network is generated by sprouting angiogenesis and consisting of one parent vessel connected to the network while taking into account the non-continuous behavior of blood, adaptability of capillary diameter to hemodynamics and metabolic stimuli, non-Newtonian blood flow, and phase separation of blood flow in capillary bifurcation. The incorporation of the outlined components beyond the previous models provides a more realistic prediction of interstitial fluid flow pattern in solid tumors and surrounding tissues. Results predict higher interstitial pressure, almost two times, for realistic model compared to the simplified model.

Numerical Modeling of Interstitial Fluid Flow Coupled with Blood Flow through a Remodeled Solid Tumor Microvascular Network.

Directory of Open Access Journals (Sweden)

M Soltani

Full Text Available Modeling of interstitial fluid flow involves processes such as fluid diffusion, convective transport in extracellular matrix, and extravasation from blood vessels. To date, majority of microvascular flow modeling has been done at different levels and scales mostly on simple tumor shapes with their capillaries. However, with our proposed numerical model, more complex and realistic tumor shapes and capillary networks can be studied. Both blood flow through a capillary network, which is induced by a solid tumor, and fluid flow in tumor's surrounding tissue are formulated. First, governing equations of angiogenesis are implemented to specify the different domains for the network and interstitium. Then, governing equations for flow modeling are introduced for different domains. The conservation laws for mass and momentum (including continuity equation, Darcy's law for tissue, and simplified Navier-Stokes equation for blood flow through capillaries are used for simulating interstitial and intravascular flows and Starling's law is used for closing this system of equations and coupling the intravascular and extravascular flows. This is the first study of flow modeling in solid tumors to naturalistically couple intravascular and extravascular flow through a network. This network is generated by sprouting angiogenesis and consisting of one parent vessel connected to the network while taking into account the non-continuous behavior of blood, adaptability of capillary diameter to hemodynamics and metabolic stimuli, non-Newtonian blood flow, and phase separation of blood flow in capillary bifurcation. The incorporation of the outlined components beyond the previous models provides a more realistic prediction of interstitial fluid flow pattern in solid tumors and surrounding tissues. Results predict higher interstitial pressure, almost two times, for realistic model compared to the simplified model.

Isoflurane administration before ischemia and during reperfusion attenuates ischemia/reperfusion-induced injury of isolated rabbit lungs.

Science.gov (United States)

Liu, R; Ishibe, Y; Ueda, M; Hang, Y

1999-09-01

To investigate the effects of isoflurane on ischemia/ reperfusion (IR)-induced lung injury, we administered isoflurane before ischemia or during reperfusion. Isolated rabbit lungs were divided into the following groups: control (n = 6), perfused and ventilated for 120 min without ischemia; ISO-control (n = 6), 1 minimum alveolar anesthetic concentration (MAC) isoflurane was administered for 30 min before 120 min continuous perfusion; IR (n = 6), ischemia for 60 min, followed by 60 min reperfusion; IR-ISO1 and IR-ISO2, ischemia followed by reperfusion and 1 MAC (n = 6) or 2 MAC (n = 6) isoflurane for 60 min; ISO-IR (n = 6), 1 MAC isoflurane was administered for 30 min before ischemia, followed by IR. During these maneuvers, we measured total pulmonary vascular resistance (Rt), coefficient of filtration (Kfc), and lung wet to dry ratio (W/D). The results indicated that administration of isoflurane during reperfusion inhibited an IR-induced increase in Kfc and W/D ratio. Furthermore, isoflurane at 2 MAC, but not 1 MAC, significantly inhibited an IR-induced increase in Rt. The administration of isoflurane before ischemia significantly attenuated the increase in IR-induced Kfc, W/D, and Rt. Our results suggest that the administration of isoflurane before ischemia and during reperfusion protects against ischemia-reperfusion-induced injury in isolated rabbit lungs.

Enhanced Local Skeletal Muscle Oxidative Capacity and Microvascular Blood Flow Following 7-Day Ischemic Preconditioning in Healthy Humans

Directory of Open Access Journals (Sweden)

Owen Jeffries

2018-05-01

Full Text Available Ischemic preconditioning (IPC, which involves intermittent periods of ischemia followed by reperfusion, is an effective clinical intervention that reduces the risk of myocardial injury and confers ischemic tolerance to skeletal muscle. Repeated bouts of IPC have been shown to stimulate long-term changes vascular function, however, it is unclear what metabolic adaptations may occur locally in the muscle. Therefore, we investigated 7 days of bilateral lower limb IPC (4 × 5 min above limb occlusion pressure (220 mmHg; n = 10, or sham (20 mmHg; n = 10, on local muscle oxidative capacity and microvascular blood flow. Oxidative capacity was measured using near-infrared spectroscopy (NIRS during repeated short duration arterial occlusions (300 mmHg. Microvascular blood flow was assessed during the recovery from submaximal isometric plantar flexion exercises at 40 and 60% of maximal voluntary contraction (MVC. Following the intervention period, beyond the late phase of protection (72 h, muscle oxidative recovery kinetics were speeded by 13% (rate constant pre 2.89 ± 0.47 min-1 vs. post 3.32 ± 0.69 min-1; P < 0.05 and resting muscle oxygen consumption (mO2 was reduced by 16.4% (pre 0.39 ± 0.16%.s-1 vs. post 0.33 ± 0.14%.s-1; P < 0.05. During exercise, changes in deoxygenated hemoglobin (HHb from rest to steady state were reduced at 40 and 60% MVC (16 and 12%, respectively, P < 0.05 despite similar measures of total hemoglobin (tHb. At the cessation of exercise, the time constant for recovery in oxygenated hemoglobin (O2Hb was accelerated at 40 and 60% MVC (by 33 and 43%, respectively suggesting enhanced reoxygenation in the muscle. No changes were reported for systemic measures of resting heart rate or blood pressure. In conclusion, repeated bouts of IPC over 7 consecutive days increased skeletal muscle oxidative capacity and microvascular muscle blood flow. These findings are consistent with enhanced mitochondrial and vascular function following

A dynamic model of renal blood flow autoregulation

DEFF Research Database (Denmark)

Holstein-Rathlou, N H; Marsh, D J

1994-01-01

To test whether a mathematical model combining dynamic models of the tubuloglomerular feedback (TGF) mechanism and the myogenic mechanism was sufficient to explain dynamic autoregulation of renal blood flow, we compared model simulations with experimental data. To assess the dynamic characteristics...... of renal autoregulation, a broad band perturbation of the arterial pressure was employed in both the simulations and the experiments. Renal blood flow and tubular pressure were used as response variables in the comparison. To better approximate the situation in vivo where a large number of individual...... data, which shows a unimodal curve for the admittance phase. The ability of the model to reproduce the experimental data supports the hypothesis that dynamic autoregulation of renal blood flow is due to the combined action of TGF and the myogenic response....

Luteal blood flow in patients undergoing GnRH agonist long protocol

Directory of Open Access Journals (Sweden)

Takasaki Akihisa

2011-01-01

Full Text Available Abstract Background Blood flow in the corpus luteum (CL is closely related to luteal function. It is unclear how luteal blood flow is regulated. Standardized ovarian-stimulation protocol with a gonadotropin-releasing hormone agonist (GnRHa long protocol causes luteal phase defect because it drastically suppresses serum LH levels. Examining luteal blood flow in the patient undergoing GnRHa long protocol may be useful to know whether luteal blood flow is regulated by LH. Methods Twenty-four infertile women undergoing GnRHa long protocol were divided into 3 groups dependent on luteal supports; 9 women were given ethinylestradiol plus norgestrel (Planovar orally throughout the luteal phase (control group; 8 women were given HCG 2,000 IU on days 2 and 4 day after ovulation induction in addition to Planovar (HCG group; 7 women were given vitamin E (600 mg/day orally throughout the luteal phase in addition to Planovar (vitamin E group. Blood flow impedance was measured in each CL during the mid-luteal phase by transvaginal color-pulsed-Doppler-ultrasonography and was expressed as a CL-resistance index (CL-RI. Results Serum LH levels were remarkably suppressed in all the groups. CL-RI in the control group was more than the cutoff value (0.51, and only 2 out of 9 women had CL-RI values Conclusion Patients undergoing GnRHa long protocol had high luteal blood flow impedance with very low serum LH levels. HCG administration improved luteal blood flow impedance. This suggests that luteal blood flow is regulated by LH.

Nocturnal variations in peripheral blood flow, systemic blood pressure, and heart rate in humans

DEFF Research Database (Denmark)

Sindrup, J H; Kastrup, J; Christensen, H

1991-01-01

Subcutaneous adipose tissue blood flow rate, together with systemic arterial blood pressure and heart rate under ambulatory conditions, was measured in the lower legs of 15 normal human subjects for 12-20 h. The 133Xe-washout technique, portable CdTe(Cl) detectors, and a portable data storage uni.......0001). The synchronism of the nocturnal subcutaneous hyperemia and the decrease in systemic mean arterial blood pressure point to a common, possibly central nervous or humoral, eliciting mechanism.......Subcutaneous adipose tissue blood flow rate, together with systemic arterial blood pressure and heart rate under ambulatory conditions, was measured in the lower legs of 15 normal human subjects for 12-20 h. The 133Xe-washout technique, portable CdTe(Cl) detectors, and a portable data storage unit...

Regional blood flow studies with radioisotopes

International Nuclear Information System (INIS)

Holman, B.L.; McNiel, B.J.; Adelstein, S.J.

1975-01-01

The methodological approaches to blood flow analysis include (1) diffusible indicator methods, (2) clearance techniques and (3) nondiffusible indicator methods. In each case, accurate measurements of blood flow can be obtained by developing mathematical models which relate the time-dependent observation derived from following the fate of a radiotracer as a function of time to the physiological process itself. Application of these models to biological systems involves constraints and necessitates compromises which may affect the validity of the measurements. Nevertheless, when these techniques are carefully applied and adequately validated, they have provided critical physiological information about such organ systems as the brain and kidney and promise to provide diagnostic information in patients with suspected coronary and peripheral vascular disease

Pulmonary and systemic blood flow contributions to upper airways in canine lung

International Nuclear Information System (INIS)

Barman, S.A.; Ardell, J.L.; Parker, J.C.; Perry, M.L.; Taylor, A.E.

1988-01-01

The blood flow contributions and drainage patterns of the pulmonary and systemic circulations in the upper airways (trachea and main bronchi) were assessed in anesthetized dogs by injecting 15-μm radiolabeled microspheres into the right and left heart, respectively. After the animals were killed, the tracheal cartilage, tracheal muscle-mucosa, and main bronchi were excised. The tracheal cartilage and tracheal muscle-mucosa were divided into lower, middle, and upper segments for blood flow determinations. The pulmonary contribution to tracheal blood flow was very small, being higher in the lower segments. The systemic contribution to these same tracheal regions was significantly higher, and higher in the upper segments. The pulmonary and systemic circulations each contributed ∼50% to the main bronchi blood flow. The pulmonary blood flow contribution alone to the trachea and main bronchi was also determined in subsequent experiments that utilized the isolated lung, and these blood flows were not significantly different from the pulmonary contribution measured in the intact lungs. The present results indicate that the systemic (bronchial) circulation is the primary source of tracheal blood flow and that both the pulmonary and systemic circulations may contribute ∼50% of the blood flow to the main bronchi in dog lungs

Relationship among visual field, blood flow, and neural structure measurements in glaucoma.

Science.gov (United States)

Hwang, John C; Konduru, Ranjith; Zhang, Xinbo; Tan, Ou; Francis, Brian A; Varma, Rohit; Sehi, Mitra; Greenfield, David S; Sadda, Srinivas R; Huang, David

2012-05-17

To determine the relationship among visual field, neural structural, and blood flow measurements in glaucoma. Case-control study. Forty-seven eyes of 42 patients with perimetric glaucoma were age-matched with 27 normal eyes of 27 patients. All patients underwent Doppler Fourier-domain optical coherence tomography to measure retinal blood flow and standard glaucoma evaluation with visual field testing and quantitative structural imaging. Linear regression analysis was performed to analyze the relationship among visual field, blood flow, and structure, after all variables were converted to logarithmic decibel scale. Retinal blood flow was reduced in glaucoma eyes compared to normal eyes (P flow and structural loss of rim area and retinal nerve fiber layer (RNFL). There was no correlation or paradoxical correlation between blood flow and structure. Multivariate regression analysis revealed that reduced blood flow and structural loss are independent predictors of visual field loss. Each dB decrease in blood flow was associated with at least 1.62 dB loss in mean deviation (P ≤ 0.001), whereas each dB decrease in rim area and RNFL was associated with 1.15 dB and 2.56 dB loss in mean deviation, respectively (P ≤ 0.03). There is a close link between reduced retinal blood flow and visual field loss in glaucoma that is largely independent of structural loss. Further studies are needed to elucidate the causes of the vascular dysfunction and potential avenues for therapeutic intervention. Blood flow measurement may be useful as an independent assessment of glaucoma severity.

In vivo analysis of physiological 3D blood flow of cerebral veins

Energy Technology Data Exchange (ETDEWEB)

Schuchardt, Florian; Schroeder, Laure; Baeuerle, Jochen; Harloff, Andreas [University Medical Centre, Department of Neurology, Freiburg (Germany); Anastasopoulos, Constantin [University Medical Center, Department of Neuropaediatrics and Muscle Disorders, Freiburg (Germany); University Medical Centre, Department of Neuroradiology, Freiburg (Germany); Markl, Michael [Northwestern University, Department of Radiology, Feinberg School of Medicine and McCormick School of Engineering, Chicago, IL (United States); Hennemuth, Anja; Drexl, Johann [Fraunhofer MEVIS, Bremen (Germany); Valdueza, Jose M. [Neurological Center, Segeberger Kliniken, Bad Segeberg (Germany); Mader, Irina [University Medical Centre, Department of Neuroradiology, Freiburg (Germany)

2015-08-15

To visualize and quantify physiological blood flow of intracranial veins in vivo using time-resolved, 3D phase-contrast MRI (4D flow MRI), and to test measurement accuracy. Fifteen healthy volunteers underwent repeated ECG-triggered 4D flow MRI (3 Tesla, 32-channel head coil). Intracranial venous blood flow was analysed using dedicated software allowing for blood flow visualization and quantification in analysis planes at the superior sagittal, straight, and transverse sinuses. MRI was evaluated for intra- and inter-observer agreement and scan-rescan reproducibility. Measurements of the transverse sinuses were compared with transcranial two-dimensional duplex ultrasound. Visualization of 3D blood flow within cerebral sinuses was feasible in 100 % and within at least one deep cerebral vein in 87 % of the volunteers. Blood flow velocity/volume increased along the superior sagittal sinus and was lower in the left compared to the right transverse sinus. Intra- and inter-observer reliability and reproducibility of blood flow velocity (mean difference 0.01/0.02/0.02 m/s) and volume (mean difference 0.0002/-0.0003/0.00003 l/s) were good to excellent. High/low velocities were more pronounced (8 % overestimation/9 % underestimation) in MRI compared to ultrasound. Four-dimensional flow MRI reliably visualizes and quantifies three-dimensional cerebral venous blood flow in vivo and is promising for studies in patients with sinus thrombosis and related diseases. (orig.)

Computational model on pulsatile flow of blood through a tapered ...

Indian Academy of Sciences (India)

S PRIYADHARSHINI

2017-11-02

Nov 2, 2017 ... It is pertinent to note that the magnitudes of flow resistance are higher in the case of ... mathematical model on non-Newtonian flow of blood through a ..... The important predictions of the present investigation are enumerating the .... drug carriers for targeted drug delivery, reducing blood flow at the time of ...

Total and regional blood flows in vascularized skeletal muscle grafts in rabbits

International Nuclear Information System (INIS)

Burton, H.W.; Stevenson, T.R.; Dysko, R.C.; Gallagher, K.P.; Faulkner, J.A.

1988-01-01

The transplantation of whole skeletal muscles is a common clinical procedure. Although atypical blood flows have been reported in small free muscle grafts, the blood flow of large neurovascular-intact (NVI) and neurovascular-anastomosed (NVA) grafts have not been measured. Because the maximum specific force (N/cm 2 ) of NVI and NVA grafts is 65% that of control muscles, we hypothesized that total and regional blood flows of NVI and NVA grafts at rest and during twitch contractions are significantly lower than lower flows of control muscles. In rabbits, blood flows of control rectus femoris (RFM) muscles and NVI and NVA grafts of RFM muscles were measured by the radioactive-microsphere technique. Total blood flows in grafts were not different from the control RFM muscle values, except for a higher resting flow in NVA grafts and a lower flow at 3 Hz in NVI grafts. Minor variations in regional flows were observed. We conclude that the operative procedures of grating and repair of blood vessels affect the vascular bed of muscles minimally, and the deficits observed in grafts do not arise from inadequate perfusion

Effect of a combined treatment with erythropoietin and melatonin on renal ischemia reperfusion injury in male rats.

Science.gov (United States)

Ahmadiasl, Nasser; Banaei, Shokofeh; Alihemati, Alireza; Baradaran, Behzad; Azimian, Ehsan

2014-12-01

Renal ischemia reperfusion (IR) is an important cause of renal dysfunction. It contributes to the development of acute renal failure. Oxidative damage from reactive oxygen species is considered to be the principal component involved in the pathophysiological tissue alterations observed during IR. The purpose of this study was to evaluate the effect of a combined treatment with erythropoietin (EPO) plus melatonin (MEL), which are known anti-inflammatory and antioxidant agents, in IR-induced renal injury in rats. Wistar Albino rats were unilaterally nephrectomized and subjected to 45 min of renal pedicle occlusion followed by 24 h of reperfusion. MEL (10 mg/kg, i.p) and EPO (5000 U/kg, i.p) were administered prior to ischemia. After 24 h of reperfusion, blood samples were collected for the determination of superoxide dismutase (SOD), glutathione peroxidase (GPx), plasma levels of total antioxidant capacity (TAC), and malondialdehyde (MDA) and serum urea level. Also, renal samples were taken for histological evaluation. Ischemia reperfusion significantly increased urea, blood SOD, and GPx levels. Histological findings of the IR group indicated that there was increase in tubular and glomerular hyaline cast, thickening of Bowman capsule basement membrane, and renal impairment in the glomerular epithelium. Treatment with EPO and MEL significantly decreased blood SOD, GPx, and urea levels and increased TAC level. In the EPO + MEL group, while the histopathological changes were lower than those in EPO group, they were the same as MEL group. EPO and MEL combination treatment exerted more nephroprotective effects than EPO treatment and nearly had protective effects similar to MEL treatment.

Calf blood flow at rest evaluated by thermal measurement with tissue temperature and heat flow and 133Xe clearance

International Nuclear Information System (INIS)

Tamura, Toshiyo; Togawa, Tatsuo; Fukuoka, Masakazu; Kawakami, Kenji.

1982-01-01

The regional blood flow in the calf was determined simultaneously by thermal measurement and by 133 Xe clearance technique. Calf blood flow (Ft) by thermal measurement was accounted for by the equation of the form Ft=(CdT*d+Ho-Mb)/rho sub(b)c su b(D) (Ta-Td), where Cd is thermal capacitance of the calf compartment, T*d is the change of calf tissue temperature, Ta is arterila blood temperature, Td is calf tissue temperature, Ho is the heat dissipation from the compartment to the environment, Mb is estimated metabolism of the calf tissue and rho sub(b)c sub(b) is the product of density and specific heat of blood. The healthy men were chosen for the experiments. Total calf blood flow was 2.53+-1.31ml/(min-100ml calf), and muscle blood flow was 2.63+-1.69ml/(min- 100ml muscle) and skin blood flow 7.19+-3.83ml/(min-100ml skin) measured by 133 Xe clearance. On the basis of the results, an estimate has been made of the proportions of the calf volume which can be ascribed to skin and muscle respectively. Estimated muscle and skin blood flow were correlated with total calf blood flow(r=0.98). (author)

Non-gated fetal MRI of umbilical blood flow in an acardiac twin

Energy Technology Data Exchange (ETDEWEB)

Hata, Nobuhiko [University of Tokyo, Graduate School of Information Science and Technology, Tokyo (Japan); Brigham and Women' s Hospital, Department of Radiology, Boston, MA (United States); Wada, Toru [University of Tokyo, Graduate School of Information Science and Technology, Tokyo (Japan); Kashima, Kyoko; Okada, Yoshiyuki [National Center for Child Health and Development, Department of Radiology, Tokyo (Japan); Unno, Nobuya [Nagano Children' s Hospital, Center for Perinatal Medicine, Nagano (Japan); Kitagawa, Michihiro [National Center for Child Health and Development, Department of Prenatal Medicine and Maternal Care, Tokyo (Japan); Chiba, Toshio [National Center for Child Health and Development, Department of Strategic Medicine, Tokyo (Japan)

2005-08-01

Currently, the standard method of diagnosis of twin reversed arterial perfusion (TRAP) sequence is ultrasound imaging. The use of MRI for flow visualization may be a useful adjunct to US imaging for assessing the presence of retrograde blood flow in the acardiac fetus and/or umbilical artery. The technical challenge in fetal MRI flow imaging, however, is that fetal electrocardiogram (ECG) monitoring required for flow imaging is currently unavailable in the MRI scanner. A non-gated MRI flow imaging technique that requires no ECG monitoring was developed using the t-test to detect blood flow in 20 slices of phase-contrast MRI images randomly scanned at the same location over multiple cardiac cycles. A feasibility study was performed in a 24-week acardiac twin that showed no umbilical flow sonographically. Non-gated MRI flow images clearly indicated the presence of blood flow in the umbilical artery to the acardiac twin; however, there was no blood flow beyond the abdomen. This study leads us to conjecture that non-gated MRI flow imaging is sensitive in detecting low-range blood flow velocity and can be an adjunct to Doppler US imaging. (orig.)

Non-gated fetal MRI of umbilical blood flow in an acardiac twin

International Nuclear Information System (INIS)

Hata, Nobuhiko; Wada, Toru; Kashima, Kyoko; Okada, Yoshiyuki; Unno, Nobuya; Kitagawa, Michihiro; Chiba, Toshio

2005-01-01

Currently, the standard method of diagnosis of twin reversed arterial perfusion (TRAP) sequence is ultrasound imaging. The use of MRI for flow visualization may be a useful adjunct to US imaging for assessing the presence of retrograde blood flow in the acardiac fetus and/or umbilical artery. The technical challenge in fetal MRI flow imaging, however, is that fetal electrocardiogram (ECG) monitoring required for flow imaging is currently unavailable in the MRI scanner. A non-gated MRI flow imaging technique that requires no ECG monitoring was developed using the t-test to detect blood flow in 20 slices of phase-contrast MRI images randomly scanned at the same location over multiple cardiac cycles. A feasibility study was performed in a 24-week acardiac twin that showed no umbilical flow sonographically. Non-gated MRI flow images clearly indicated the presence of blood flow in the umbilical artery to the acardiac twin; however, there was no blood flow beyond the abdomen. This study leads us to conjecture that non-gated MRI flow imaging is sensitive in detecting low-range blood flow velocity and can be an adjunct to Doppler US imaging. (orig.)

Total hepatofugal portal blood flow in cirrhosis demonstrated by transhepatic portography

International Nuclear Information System (INIS)

Burcharth, F.; Aagaard, J.; Herlev Hospital

1988-01-01

We investigated 108 patients with cirrhosis of the liver and portal hypertension by percutaneous transhepatic portography to demonstrate the occurrence and frequency of total hepatofugal portal blood flow. Sixteen patients (14.8%) had a total hepatofugal portal blood flow. The aetiology of portal hypertension and the portal pressure did not differ from that in the group of patients with hepatopetal portal blood flow. A significantly higher percentage of patients in the group with hepatofugal flow had gastro-oesophageal varices (P [de

Investigation of spiral blood flow in a model of arterial stenosis

OpenAIRE

Paul, M.C.; Larman, A.

2009-01-01

The spiral component of blood flow has both beneficial and detrimental effects in human circulatory system [Stonebridge PA, Brophy CM. Spiral laminar flow in arteries? Lancet 1991; 338: 1360–1]. We investigate the effects of the spiral blood flow in a model of three-dimensional arterial stenosis with a 75% cross-sectional area reduction at the centre by means of computational fluid dynamics (CFD) techniques. The standard κ–ω model is employed for simulation of the blood flow for the...

[Effects of flunarizine and vitamin C on hemodynamics in rat heart subjected to ischemia-reperfusion].

Science.gov (United States)

Xian, Y; Lan, T; Wang, Y

1998-09-01

Langendorff perfusion isolated rat heart was subjected to total global ischemia (coronary flow rate is equal to zero) for 10 minutes and reperfusion for 15 minutes. The heart rate (HR), left ventricular developed pressure (LVDP), coronary flow rate (CFR), electrocardiogram (ECG) and the effects of calcium antagonist-flunarizine (FNZ) and/or oxygen free radical scavenger--vitamine C on the above parameters were observed. The results showed that FNZ dilated coronary vessel (P Vitamine C did not affect HR, LVP and CFR. The recovery of the product of HR and LVDP-Rate Pressure Product (RPP) in the FNZ + Vit. C group, Vit. C group and FNZ group was significantly higher than that in the control group (P C may improve the recovery of heart function after reperfusion.

Insight of Human Stroke from blood flow and blood pressure

Science.gov (United States)

Chen, Zhi; Ivanov, Plamen Ch.; Hu, Kun; Stanley, H. Eugene

2003-03-01

Stroke is is one of the leading cause of death and disability in the world. It is well believed that stroke is caused by the disturbance of cerebrovascular autoregulation. We investigate the blood flow on the left and right middle cerebral artery and beat-to-beat blood pressure simultaneously measured from the finger, for both subjects with stroke and healthy subjects. Synchronization technique is used to distinguish the difference between these two groups.

Kinetics of thallium-201 in reperfused canine myocardium after coronary artery occlusion

International Nuclear Information System (INIS)

Okada, R.D.

1984-01-01

To study the kinetics of thallium-201 in nonsalvaged acutely infarcted myocardium and salvaged myocardium, the tracer was administered after experimental left anterior descending coronary artery reperfusion 2 hours after occlusion. In 19 dogs, thallium activity was then monitored for 4 hours in the reperfused anterior wall and normal posterior wall using miniature cadmium telluride radiation detectors. After sacrifice, 13 of the dogs were found to have an infarcted anterior wall by triphenyltetrazolium-chloride staining. In these dogs, mean (+/- standard deviation) fractional 4 hour thallium clearance was 0.33 +/- 0.08 for the infarct zone and 0.15 +/- 0.06 for the normal control zone (p less than 0.001). When computer-modeled, the clearance curve from the infarct zone was biexponential. The second exponential clearance curve from the infarct zone began 19.1 +/- 3.2 minutes after tracer administration, and was indistinguishable from the monoexponential clearance curve from the normal control zone. Thallium clearance from the blood pool was triexponential, the final exponential clearance curve being indistinguishable from the normal control zone clearance curve. Six dogs were found to have a salvaged noninfarcted anterior wall by triphenyltetrazolium-chloride staining. In these dogs, mean fractional 4 hour thallium clearance was 0.20 +/- 0.07 for the reperfused zone, and 0.19 +/- 0.08 for the normal control zone (p . NS). When computer-modeled, clearance curves for the reperfused and control zones were monoexponential. The monoexponential clearance curve for the salvaged reperfused zone was indistinguishable from the monoexponential clearance curve for normal myocardium

Longitudinal optical monitoring of blood flow in breast tumors during neoadjuvant chemotherapy

Science.gov (United States)

Cochran, J. M.; Chung, S. H.; Leproux, A.; Baker, W. B.; Busch, D. R.; DeMichele, A. M.; Tchou, J.; Tromberg, B. J.; Yodh, A. G.

2017-06-01

We measure tissue blood flow markers in breast tumors during neoadjuvant chemotherapy and investigate their correlation to pathologic complete response in a pilot longitudinal patient study (n  =  4). Tumor blood flow is quantified optically by diffuse correlation spectroscopy (DCS), and tissue optical properties, blood oxygen saturation, and total hemoglobin concentration are derived from concurrent diffuse optical spectroscopic imaging (DOSI). The study represents the first longitudinal DCS measurement of neoadjuvant chemotherapy in humans over the entire course of treatment; it therefore offers a first correlation between DCS flow indices and pathologic complete response. The use of absolute optical properties measured by DOSI facilitates significant improvement of DCS blood flow calculation, which typically assumes optical properties based on literature values. Additionally, the combination of the DCS blood flow index and the tissue oxygen saturation from DOSI permits investigation of tissue oxygen metabolism. Pilot results from four patients suggest that lower blood flow in the lesion-bearing breast is correlated with pathologic complete response. Both absolute lesion blood flow and lesion flow relative to the contralateral breast exhibit potential for characterization of pathological response. This initial demonstration of the combined optical approach for chemotherapy monitoring provides incentive for more comprehensive studies in the future and can help power those investigations.

Influence of Gravity on Blood Volume and Flow Distribution

Science.gov (United States)

Pendergast, D.; Olszowka, A.; Bednarczyk, E.; Shykoff, B.; Farhi, L.

1999-01-01

In our previous experiments during NASA Shuttle flights SLS 1 and 2 (9-15 days) and EUROMIR flights (30-90 days) we observed that pulmonary blood flow (cardiac output) was elevated initially, and surprisingly remained elevated for the duration of the flights. Stroke volume increased initially and then decreased, but was still above 1 Gz values. As venous return was constant, the changes in SV were secondary to modulation of heart rate. Mean blood pressure was at or slightly below 1 Gz levels in space, indicating a decrease in total peripheral resistance. It has been suggested that plasma volume is reduced in space, however cardiac output/venous return do not return to 1 Gz levels over the duration of flight. In spite of the increased cardiac output, central venous pressure was not elevated in space. These data suggest that there is a change in the basic relationship between cardiac output and central venous pressure, a persistent "hyperperfusion" and a re-distribution of blood flow and volume during space flight. Increased pulmonary blood flow has been reported to increase diffusing capacity in space, presumably due to the improved homogeneity of ventilation and perfusion. Other studies have suggested that ventilation may be independent of gravity, and perfusion may not be gravity- dependent. No data for the distribution of pulmonary blood volume were available for flight or simulated microgravity. Recent studies have suggested that the pulmonary vascular tree is influenced by sympathetic tone in a manner similar to that of the systemic system. This implies that the pulmonary circulation is dilated during microgravity and that the distribution of blood flow and volume may be influenced more by vascular control than by gravity. The cerebral circulation is influenced by sympathetic tone similarly to that of the systemic and pulmonary circulations; however its effects are modulated by cerebral autoregulation. Thus it is difficult to predict if cerebral perfusion is

Ocular blood flow decreases during passive heat stress in resting humans

OpenAIRE

Ikemura, Tsukasa; Miyaji, Akane; Kashima, Hideaki; Yamaguchi, Yuji; Hayashi, Naoyuki

2013-01-01

Background Heat stress induces various physiological changes and so could influence ocular circulation. This study examined the effect of heat stress on ocular blood flow. Findings Ocular blood flow, end-tidal carbon dioxide (P ETCO2) and blood pressure were measured for 12 healthy subjects wearing water-perfused tube-lined suits under two conditions of water circulation: (1) at 35°C (normothermia) for 30 min and (2) at 50°C for 90 min (passive heat stress). The blood-flow velocities in the s...

Emesis, radiation exposure, and local cerebral blood flow in the ferret

International Nuclear Information System (INIS)

Tuor, U.I.; Kondysar, M.H.; Harding, R.K.

1988-01-01

We examined the sensitivity of the ferret to emetic stimuli and the effect of radiation exposure near the time of emesis on local cerebral blood flow. Ferrets vomited following the administration of either apomorphine (approx 45% of the ferrets tested) or peptide YY (approx 36% of those tested). Exposure to radiation was a very potent emetic stimulus, but vomiting could be prevented by restraint of the hindquarters of the ferret. Local cerebral blood flow was measured using a quantitative autoradiographic technique and with the exception of several regions in the telencephalon and cerebellum, local cerebral blood flow in the ferret was similar to that in the rat. In animals with whole-body exposure to moderate levels of radiation (4 Gy of 137 Cs), mean arterial blood pressure was similar to that in the control group. However, 15-25 min following irradiation there was a general reduction of local cerebral blood flow ranging from 7 to 33% of that in control animals. These cerebral blood flow changes likely correspond to a reduced activation of the central nervous system

Limb Remote Ischemic Postconditioning Reduces Ischemia-Reperfusion Injury by Inhibiting NADPH Oxidase Activation and MyD88-TRAF6-P38MAP-Kinase Pathway of Neutrophils

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Gangling Chen

2016-11-01

Full Text Available Limb remote ischemic postconditioning (LRIP has been confirmed to reduce the ischemia-reperfusion injury but its mechanisms are still not clear. This study clarified the mechanism of LRIP based on the nicotinamide-adenine dinucleotide phosphate (NADPH oxidase and Myeloid differentiation factor 88 (MyD88-Tumor necrosis factor (TNF receptor-associated factor 6 (TRAF6-P38 pathway of neutrophils. Rat middle cerebral artery occlusion (MCAO model was used in this study. Ischemia-reperfusion injury was carried out by MCAO 1.5 h followed by 24 h reperfusion. LRIP operation was performed to the left femoral artery at 0, 1 or 3 h after reperfusion. Behavioral testing, including postural reflex test, vibrissae-elicited forelimb placing test and tail hang test, showed that LRIP operated at 0 h of reperfusion could significantly ameliorate these behavioral scores. Pathological examinations, infarct size, Myeloperoxidase (MPO activity showed that LRIP operated at 0 h of reperfusion could significantly ameliorate the pathological scores, reduce the infarct size and MPO activity in the brain and increase the MPO activity in the left leg. By using Neutrophil counting, immunofluorescence and real-time PCR techniques, we found that LRIP operated at 0 h of reperfusion could reduce neutrophil counts in the peripheral blood and downregulate the activation of neutrophil in the peripheral blood and rat brain. Western blots revealed that MyD88, TRAF6, p38 mitogen-activated protein kinase (p38-MAPK in neutrophils and the phosphorylation of p47phox (Ser 304 and Ser 345 in neutrophil could be downregulated by LRIP. Our study suggests that LRIP inhibits the number and activation of neutrophils in the rat brain and peripheral blood linked to down-regulating the activation of NADPH oxidase in neutrophils by MyD88/TRAF6/p38-MAPK pathway.

Oscillations and Multiple Equilibria in Microvascular Blood Flow.

Science.gov (United States)

Karst, Nathaniel J; Storey, Brian D; Geddes, John B

2015-07-01

We investigate the existence of oscillatory dynamics and multiple steady-state flow rates in a network with a simple topology and in vivo microvascular blood flow constitutive laws. Unlike many previous analytic studies, we employ the most biologically relevant models of the physical properties of whole blood. Through a combination of analytic and numeric techniques, we predict in a series of two-parameter bifurcation diagrams a range of dynamical behaviors, including multiple equilibria flow configurations, simple oscillations in volumetric flow rate, and multiple coexistent limit cycles at physically realizable parameters. We show that complexity in network topology is not necessary for complex behaviors to arise and that nonlinear rheology, in particular the plasma skimming effect, is sufficient to support oscillatory dynamics similar to those observed in vivo.

Pulsatile blood flow, shear force, energy dissipation and Murray's Law

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Bengtsson Hans-Uno

2006-08-01

Full Text Available Abstract Background Murray's Law states that, when a parent blood vessel branches into daughter vessels, the cube of the radius of the parent vessel is equal to the sum of the cubes of the radii of daughter blood vessels. Murray derived this law by defining a cost function that is the sum of the energy cost of the blood in a vessel and the energy cost of pumping blood through the vessel. The cost is minimized when vessel radii are consistent with Murray's Law. This law has also been derived from the hypothesis that the shear force of moving blood on the inner walls of vessels is constant throughout the vascular system. However, this derivation, like Murray's earlier derivation, is based on the assumption of constant blood flow. Methods To determine the implications of the constant shear force hypothesis and to extend Murray's energy cost minimization to the pulsatile arterial system, a model of pulsatile flow in an elastic tube is analyzed. A new and exact solution for flow velocity, blood flow rate and shear force is derived. Results For medium and small arteries with pulsatile flow, Murray's energy minimization leads to Murray's Law. Furthermore, the hypothesis that the maximum shear force during the cycle of pulsatile flow is constant throughout the arterial system implies that Murray's Law is approximately true. The approximation is good for all but the largest vessels (aorta and its major branches of the arterial system. Conclusion A cellular mechanism that senses shear force at the inner wall of a blood vessel and triggers remodeling that increases the circumference of the wall when a shear force threshold is exceeded would result in the observed scaling of vessel radii described by Murray's Law.

Prophylactic Treatment with Cerium Oxide Nanoparticles Attenuate Hepatic Ischemia Reperfusion Injury in Sprague Dawley Rats

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Nandini D.P.K. Manne

2017-07-01

Full Text Available Background: Hepatic ischemia reperfusion is one the main causes for graft failure following transplantation. Although, the molecular events that lead to hepatic failure following ischemia reperfusion (IR are diverse and complex, previous studies have shown that excessive formation of reactive oxygen species (ROS are responsible for hepatic IR injury. Cerium oxide (CeO2 nanoparticles have been previously shown to act as an anti-oxidant and anti-inflammatory agent. Here, we evaluated the protective effects of CeO2 nanoparticles on hepatic ischemia reperfusion injury. Methods: Male Sprague Dawley rats were randomly assigned to one of the four groups: Control, CeO2 nanoparticle only, hepatic ischemia reperfusion (IR group and hepatic ischemia reperfusion (IR plus CeO2 nanoparticle group (IR+ CeO2. Partial warm hepatic ischemia was induced in left lateral and median lobes for 1h, followed by 6h of reperfusion. Animals were sacrificed after 6h of reperfusion and blood and tissue samples were collected and processed for various biochemical experiments. Results: Prophylactic treatment with CeO2 nanoparticles (0.5mg/kg i.v (IR+CeO2 group 1 hour prior to hepatic ischemia and subsequent reperfusion injury lead to a decrease in serum levels of alanine aminotransaminase and lactate dehydrogenase at 6 hours after reperfusion. These changes were accompanied by significant decrease in hepatocyte necrosis along with reduction in several serum inflammatory markers such as macrophage derived chemokine, macrophage inflammatory protein-2, KC/GRO, myoglobin and plasminogen activator inhibitor-1. However, immunoblotting demonstrated no significant changes in the levels of apoptosis related protein markers such as bax, bcl2 and caspase 3 in IR and IR+ CeO2 groups at 6 hours suggesting necrosis as the main pathway for hepatocyte death. Conclusion: Taken together, these data suggest that CeO2 nanoparticles attenuate IR induced cell death and can be used as a prophylactic

Bone and bone-marrow blood flow in chronic granulocytic leukemia and primary myelofibrosis

International Nuclear Information System (INIS)

Lahtinen, R.; Lahtinen, T.; Romppanen, T.

1982-01-01

Blood flow in hematopoietic bone marrow and in nonhematopoietic bone has been measured with a Xe-133 washout method in 20 patients with chronic granulocytic leukemia (CGL) and in seven with primary myelofibrosis. Age-matched healthy persons served as controls. Bone-marrow blood flow in CGL was dependent upon the phase of the disease. In the metamorphosis phase, bone-marrow blood flow was high compared with that in the well-controlled phase. Apart from the initial phase, the mean values for bone blood flow in CGL were increased compared with the values of the healthy controls. In myelofibrosis the bone blood flow was also increased. Bone-marrow blood flow in these diseases was dependent upon the cellularity of bone marrow as measured morphometrically

Simulating nailfold capillaroscopy sequences to evaluate algorithms for blood flow estimation.

Science.gov (United States)

Tresadern, P A; Berks, M; Murray, A K; Dinsdale, G; Taylor, C J; Herrick, A L

2013-01-01

The effects of systemic sclerosis (SSc)--a disease of the connective tissue causing blood flow problems that can require amputation of the fingers--can be observed indirectly by imaging the capillaries at the nailfold, though taking quantitative measures such as blood flow to diagnose the disease and monitor its progression is not easy. Optical flow algorithms may be applied, though without ground truth (i.e. known blood flow) it is hard to evaluate their accuracy. We propose an image model that generates realistic capillaroscopy videos with known flow, and use this model to quantify the effect of flow rate, cell density and contrast (among others) on estimated flow. This resource will help researchers to design systems that are robust under real-world conditions.

The multi-slice CT perfusion imaging in evaluating the prevention and treatment by edaravone on lung ischemia-reperfusion injury after pulmonary thromboembolism

Energy Technology Data Exchange (ETDEWEB)

Jianjun, Li; Renyou, Zhai; Dongpo, Zhang; Qiang, Huang; Dingke, Dai; Ping, Yu; Na, Bao [Department of Radiology, Beijing Chaoyang Hospital, Capital Medical Univ., Beijing (China)

2008-10-15

Objective: To evaluate the multi-slice CT perfusion imaging in investigating whether edaravone can prevent and treat pulmonary thromboembolism ischemia-reperfusion injury (PTE-IRI). Methods: Twenty mongrel canines were included. A Swan-Ganz catheter was introduced into the right internal jugular vein using the Seldinger technique, and then was inserted into the pulmonary artery. Balloon occlusion of the right inferior lobe pulmonary artery for 4 h was followed by removing catheter and 4 h o reperfusion. Animals were divided into four groups of A (no edaravone during ischenmia and reperfusion), B (edaravone used only during ischemia), C (edaravone used during both ischemia and reperfusion) and D group (edaravone used only during reperfusion) (n=5 per group). Every group was divided into three time points including before ischemia, 4 h after ischemia and 4 h after reperfusion. CT scan and CT perfusion were performed at the three time points. The blood flow (BF), blood volume (BV) and mean transit time (MTT) of the bilateral inferior regional lung parenchyma were measured with the software of perfusion 3. Results: CT examination showed pulmonary edema in the right inferior lung lobe at 4 h after reperfusion. (1) The BF and MTT of A, B, C and D group were[(259.4{+-}15.7)ml{center_dot}min{sup -1{center_dot}}100 g{sup -1}, (293.7{+-} 7.9) ml{center_dot}min{sup -1{center_dot}}100 g {sup -1}, (379.4{+-}14.5)ml{center_dot}min{sup -1{center_dot}}100 g{sup -1}, (382.5{+-}16.6)ml{center_dot}min{sup -1{center_dot}}. 100 g{sup -1}] and [(3.1{+-}0.2)s, (2.6{+-}0.2)s, (2.2{+-}0.1)s, (1.9{+-}0.2)s] respectively at 4 h after reperfusion. The BF and MTT were statistically different (P<0.01) between groups (A and B, A and C, A and D, B and C, B and D) except between group C and D (the P value >0.05) at 4 h after reperfusion, but the BV was not statistically different between groups (P>0.05). (2) The BF [(397.2{+-} 19.2)ml{center_dot}min{sup -1{center_dot}}100 g{sup -1} and (259

Dynamic properties of blood flow and leukocyte mobilization in infected flaps

International Nuclear Information System (INIS)

Feng, L.J.; Price, D.C.; Mathes, S.J.; Hohn, D.

1990-01-01

Two aspects of the inflammatory response to infection--blood flow alteration and leukocyte mobilization--are investigated in the canine model. The elevation of paired musculocutaneous (MC) and random pattern (RP) flaps allowed comparison of healing flaps with significant differences in blood flow (lower in random pattern flaps) and resistance to infection (greater in musculocutaneous flaps). Blood flow changes as determined by radioactive xenon washout were compared in normal skin and distal flap skin both after elevation and following bacterial inoculation. Simultaneous use of In-111 labeled leukocytes allowed determination of leukocyte mobilization and subsequent localization in response to flap infection. Blood flow significantly improved in the musculocutaneous flap in response to infection. Although total leukocyte mobilization in the random pattern flap was greater, the leukocytes in the musculocutaneous flap were localized around the site of bacterial inoculation within the dermis. Differences in the dynamic blood flow and leukocyte mobilization may, in part, explain the greater reliability of musculocutaneous flaps when transposed in the presence of infection

Directly measuring spinal cord blood flow and spinal cord perfusion pressure via the collateral network: correlations with changes in systemic blood pressure.

Science.gov (United States)

Kise, Yuya; Kuniyoshi, Yukio; Inafuku, Hitoshi; Nagano, Takaaki; Hirayasu, Tsuneo; Yamashiro, Satoshi

2015-01-01

During thoracoabdominal surgery in which segmental arteries are sacrificed over a large area, blood supply routes from collateral networks have received attention as a means of avoiding spinal cord injury. The aim of this study was to investigate spinal cord blood supply through a collateral network by directly measuring spinal cord blood flow and spinal cord perfusion pressure experimentally. In beagle dogs (n = 8), the thoracoabdominal aorta and segmental arteries L1-L7 were exposed, and a temporary bypass was created for distal perfusion. Next, a laser blood flow meter was placed on the spinal dura mater in the L5 region to measure the spinal cord blood flow. The following were measured simultaneously when the direct blood supply from segmental arteries L2-L7 to the spinal cord was stopped: mean systemic blood pressure, spinal cord perfusion pressure (blood pressure within the aortic clamp site), and spinal cord blood flow supplied via the collateral network. These variables were then investigated for evidence of correlations. Positive correlations were observed between mean systemic blood pressure and spinal cord blood flow during interruption of segmental artery flow both with (r = 0.844, P flow with and without distal perfusion (r = 0.803, P network from outside the interrupted segmental arteries, and high systemic blood pressure (∼1.33-fold higher) was needed to obtain the preclamping spinal cord blood flow, whereas 1.68-fold higher systemic blood pressure was needed when distal perfusion was halted. Spinal cord blood flow is positively correlated with mean systemic blood pressure and spinal cord perfusion pressure under spinal cord ischemia caused by clamping a wide range of segmental arteries. In open and endovascular thoracic and thoracoabdominal surgery, elevating mean systemic blood pressure is a simple and effective means of increasing spinal cord blood flow, and measuring spinal cord perfusion pressure seems to be useful for monitoring

Blood flow rate measurements with indicator techniques revisited

DEFF Research Database (Denmark)

Sejrsen, Per; Bülow, Jens

2009-01-01

In view of the emerging role, disturbances in regional blood flow rate seem to play in the pathogenesis of the metabolic syndrome; we review the concepts of the classical indicator dilution and washout techniques used for determinations of regional blood flow rate. Prerequisites, assumptions......, necessary precautions for the application of these experimental techniques are emphasized. Special attention has been carried out to elucidate the consequence of a choice of indicators having a large distribution volume in the tissues....

Insulin Preconditioning Elevates p-Akt and Cardiac Contractility after Reperfusion in the Isolated Ischemic Rat Heart

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Tamaki Sato

2014-01-01

Full Text Available Insulin induces cardioprotection partly via an antiapoptotic effect. However, the optimal timing of insulin administration for the best quality cardioprotection remains unclear. We tested the hypothesis that insulin administered prior to ischemia provides better cardioprotection than insulin administration after ischemia. Isolated rat hearts were prepared using Langendorff method and divided into three groups. The Pre-Ins group (Pre-Ins received 0.5 U/L insulin prior to 15 min no-flow ischemia for 20 min followed by 20 min of reperfusion. The Post-Ins group (Post-Ins received 0.5 U/L insulin during the reperfusion period only. The control group (Control was perfused with KH buffer throughout. The maximum of left ventricular derivative of pressure development (dP/dt(max was recorded continuously. Measurements of TNF-α and p-Akt in each time point were assayed by ELISA. After reperfusion, dP/dt(max in Pre-Ins was elevated, compared with Post-Ins at 10 minutes after reperfusion and Control at all-time points. TNF-α levels at 5 minutes after reperfusion in the Pre-Ins were lower than the others. After 5 minutes of reperfusion, p-Akt was elevated in Pre-Ins compared with the other groups. Insulin administration prior to ischemia provides better cardioprotection than insulin administration only at reperfusion. TNF-α suppression is possibly mediated via p-Akt leading to a reduction in contractile myocardial dysfunction.

Regional cerebral blood flow in schizophrenia

International Nuclear Information System (INIS)

Kanoh, Masayuki

1989-01-01

Regional cerebral blood flow (rCBF) was measured at rest using the 133 Xe inhalation technique in 40 DSM-III-diagnosed schizophrenics (22 males, 18 females: mean age 35.0 years, range 20-49 years) and 31 age-and sex-matched normal controls (16 males, 15 females: mean age 34.3 years, range 21-49 years). The absolute value (AV) and the percent value (PV) of the rCBF in schizophrenics were compared with those in controls. Correlations between rCBF and the Brief Psychiatric Rating Scale (BPRS) scores or the performance of Wisconsin Card Sorting Test (WCST) were examined in schizophrenics. Schizophrenics showed significantly lower AVs in all brain regions examined and a significantly lower PV in the left superior frontal region than controls. The hyperfrontal rCBF distribution which was found in both hemispheres in controls, was absent in the left hemisphere in schizophrenics. In schizophrenics, superior frontal blood flows were significantly negatively correlated with the negative symptom scores of the BPRS but not with the total scores and the positive symptom scores of the BPRS. In schizophrenics, inferior frontal blood flows were significantly correlated with the number of sorting categories achieved. These results indicate that rCBF in schizophrenia is reduced in the whole brain and especially in the left superior frontal region. These findings suggest a frontal lobe dysfunction in schizophrenia. (author)

Effects of hypothyroidism on the skeletal muscle blood flow response to contractions.

Science.gov (United States)

Bausch, L; McAllister, R M

2003-04-01

Hypothyroidism is associated with impaired blood flow to skeletal muscle under whole body exercise conditions. It is unclear whether poor cardiac and/or vascular function account for blunted muscle blood flow. Our experiment isolated a small group of hindlimb muscles and simulated exercise via tetanic contractions. We hypothesized that muscle blood flow would be attenuated in hypothyroid rats (HYPO) compared with euthyroid rats (EUT). Rats were made hypothyroid by mixing propylthiouracil in their drinking water (2.35 x 10-3 mol/l). Treatment efficacy was evidenced by lower serum T3 concentrations and resting heart rates in HYPO (both Pmuscles at a rate of 30 tetani/min were induced via sciatic nerve stimulation. Regional blood flows were determined by the radiolabelled microsphere method at three time points: rest, 2 min of contractions and 10 min of contractions. Muscle blood flow generally increased from rest ( approximately 5-10 ml/min per 100 g) through contractions for both groups. Further, blood flow during contractions did not differ between groups for any muscle (eg. red section of gastrocnemius muscle; EUT, 59.9 +/- 14.1; HYPO, 61.1 +/- 15.0; NS between groups). These findings indicate that hypothyroidism does not significantly impair skeletal muscle blood flow when only a small muscle mass is contracting. Our findings suggest that impaired blood flow under whole body exercise is accounted for by inadequate cardiac function rather than abnormal vascular function.

Analysis of blood flow patterns in aortic aneurysm by cine magnetic resonance imaging

International Nuclear Information System (INIS)

Matsuoka, Hiroshi

1993-01-01

Cine MRI (0.5 T) using rephased gradient echo technique was performed to study the patterns of blood flow in the aortic aneurysm of 16 patients with aortic aneurysm, and the data were compared with those of 5 healthy volunteers. In the transaxial section, the blood flow in normal aorta appeared as homogeneous high intensity during systole. On the other hand, the blood flow in the aneurysm appeared as inhomogeneous flow enhancement with flow void. In the sagittal scan, the homogeneous flow enhancement in a normal aorta was also observed during systole and its apex of flow enhancement was 'taper'. The blood flow patterns in the aneurysm were classified as 'irregular', 'zonal', 'eddy', and 'obscure' depending on the contrast of flow enhancement and flow void. Their apexes were 'taper' or 'round'. The blood flow patterns in the aneurysm were related to the size of aneurysm. In patients with a large size 'aneurysm, their flow patterns were 'eddy' or 'obscure' and the flow enhancement was 'round'. On the other hand, in patients with a small size aneurysm, their flow patterns were 'irregular' or 'zonal', and their flow enhancement was 'taper'. Though the exact mechanism of abnormal flow patterns in an aortic aneurysm remains to be determined, cine MRI gives helpful informations in assessing blood flow dynamics in the aneurysm. (author)

The effects of hypoxemia on myocardial blood flow during exercise.

Science.gov (United States)

Paridon, S M; Bricker, J T; Dreyer, W J; Reardon, M; Smith, E O; Porter, C B; Michael, L; Fisher, D J

1989-03-01

We evaluated the adequacy of regional and transmural blood flow during exercise and rapid pacing after 1 wk of hypoxemia. Seven mature mongrel dogs were made hypoxemic (mean O2 saturation = 72.4%) by anastomosis of left pulmonary artery to left atrial appendage. Catheters were placed in the left atrium, right atrium, pulmonary artery, and aorta. Atrial and ventricular pacing wires were placed. An aortic flow probe was placed to measure cardiac output. Ten nonshunted dogs, similarly instrumented, served as controls. Recovery time was approximately 1 wk. Cardiac output, mean aortic pressure, and oxygen saturation were measured at rest, with ventricular pacing, atrial pacing, and with treadmill exercise. Ventricular and atrial pace and exercise were at a heart rate of 200. Right ventricular free wall, left ventricular free wall, and septal blood flow were measured with radionuclide-labeled microspheres. Cardiac output, left atrial blood pressure, and aortic blood pressure were similar between the two groups of dogs in all testing states. Myocardial blood flow was significantly higher in the right and left ventricular free wall in the hypoxemic animals during resting and exercise testing states. Myocardial oxygen delivery was similar between the two groups of animals. Pacing resulted in an increase in myocardial blood flow in the control animals but not the hypoxemic animals.(ABSTRACT TRUNCATED AT 250 WORDS)

Simple Radiowave-Based Method For Measuring Peripheral Blood Flow Project

Science.gov (United States)

Oliva-Buisson, Yvette J.

2014-01-01

Project objective is to design small radio frequency based flow probes for the measurement of blood flow velocity in peripheral arteries such as the femoral artery and middle cerebral artery. The result will be the technological capability to measure peripheral blood flow rates and flow changes during various environmental stressors such as microgravity without contact to the individual being monitored. This technology may also lead to an easier method of detecting venous gas emboli during extravehicular activities.

Separation of platelets from other blood cells in continuous-flow by dielectrophoresis field-flow-fractionation

OpenAIRE

Piacentini, Niccolò; Mernier, Guillaume; Tornay, Raphaël; Renaud, Philippe

2011-01-01

We present a microfluidic device capable of separating platelets from other blood cells in continuous flow using dielectrophoresis field-flow-fractionation. The use of hydrodynamic focusing in combination with the application of a dielectrophoretic force allows the separation of platelets from red blood cells due to their size difference. The theoretical cell trajectory has been calculated by numerical simulations of the electrical field and flow speed, and is in agreement with the experiment...

Facial skin blood flow responses during exposures to emotionally charged movies.

Science.gov (United States)

Matsukawa, Kanji; Endo, Kana; Ishii, Kei; Ito, Momoka; Liang, Nan

2018-03-01

The changes in regional facial skin blood flow and vascular conductance have been assessed for the first time with noninvasive two-dimensional laser speckle flowmetry during audiovisually elicited emotional challenges for 2 min (comedy, landscape, and horror movie) in 12 subjects. Limb skin blood flow and vascular conductance and systemic cardiovascular variables were simultaneously measured. The extents of pleasantness and consciousness for each emotional stimulus were estimated by the subjective rating from -5 (the most unpleasant; the most unconscious) to +5 (the most pleasant; the most conscious). Facial skin blood flow and vascular conductance, especially in the lips, decreased during viewing of comedy and horror movies, whereas they did not change during viewing of a landscape movie. The decreases in facial skin blood flow and vascular conductance were the greatest with the comedy movie. The changes in lip, cheek, and chin skin blood flow negatively correlated (P < 0.05) with the subjective ratings of pleasantness and consciousness. The changes in lip skin vascular conductance negatively correlated (P < 0.05) with the subjective rating of pleasantness, while the changes in infraorbital, subnasal, and chin skin vascular conductance negatively correlated (P < 0.05) with the subjective rating of consciousness. However, none of the changes in limb skin blood flow and vascular conductance and systemic hemodynamics correlated with the subjective ratings. The mental arithmetic task did not alter facial and limb skin blood flows, although the task influenced systemic cardiovascular variables. These findings suggest that the more emotional status becomes pleasant or conscious, the more neurally mediated vasoconstriction may occur in facial skin blood vessels.

Testicular blood flow in varicocele

International Nuclear Information System (INIS)

Iwamoto, Teruaki; Hirokawa, Makoto.

1986-01-01

Radioisotopic scrotal angiography was applied for study of testicular blood flow of patients with varicocele. Following iv. bolus injection of 10 ∼ 20 mCi of Tc human serum albumine, Tc RBC or Tc pertechnetate, time activity curve of radioactivity at corresponding bilateral areas of scrotum was simultaneously generated and compared. Eighty-four patients with overt varicocele (grade 2 and 3) at left side only, were selected for the present study and eight healthy young volunteers were studied as a control group. Three patterns of time activity curves were recognized. They are as follows. Type 1, where radioactivity was accumulated quickly in left side and then decreased gradually. Bilateral time activity curves were asymmetrical. Type 2, where time activity curves rose gradually and to a higher level at the left side than at the right side. Type 3, where bilateral time activity curves increased gradually, and symmetrically. All of the control group showed the same pattern as Type 3. Of the 84 patients examined, 34 patients showed Type 1, including 7 with grade 2 and 27 with grade 3. Twenty-four patients showed Type 2. consisting of 12 with grade 2 and 12 with grade 3. Twenty-six patients showed Type 3, consisting of 14 with grade 2 and 12 with grade 3. We presumed the following about testicular blood flow in varicocele: Type 1 pattern shows retrograde blood flow from the renal vein to the internal spermatic vein, Type 2 pattern shows poor venous return through the internal spermatic vein and Type 3 pattern shows good venous return though the presence of dilatated pampiniform plexus. (author)

Partitioning of red blood cell aggregates in bifurcating microscale flows

Science.gov (United States)

Kaliviotis, E.; Sherwood, J. M.; Balabani, S.

2017-03-01

Microvascular flows are often considered to be free of red blood cell aggregates, however, recent studies have demonstrated that aggregates are present throughout the microvasculature, affecting cell distribution and blood perfusion. This work reports on the spatial distribution of red blood cell aggregates in a T-shaped bifurcation on the scale of a large microvessel. Non-aggregating and aggregating human red blood cell suspensions were studied for a range of flow splits in the daughter branches of the bifurcation. Aggregate sizes were determined using image processing. The mean aggregate size was marginally increased in the daughter branches for a range of flow rates, mainly due to the lower shear conditions and the close cell and aggregate proximity therein. A counterintuitive decrease in the mean aggregate size was apparent in the lower flow rate branches. This was attributed to the existence of regions depleted by aggregates of certain sizes in the parent branch, and to the change in the exact flow split location in the T-junction with flow ratio. The findings of the present investigation may have significant implications for microvascular flows and may help explain why the effects of physiological RBC aggregation are not deleterious in terms of in vivo vascular resistance.

Follicle vascularity coordinates corpus luteum blood flow and progesterone production.

Science.gov (United States)

de Tarso, S G S; Gastal, G D A; Bashir, S T; Gastal, M O; Apgar, G A; Gastal, E L

2017-03-01

Colour Doppler ultrasonography was used to compare the ability of preovulatory follicle (POF) blood flow and its dimensions to predict the size, blood flow and progesterone production capability of the subsequent corpus luteum (CL). Cows (n=30) were submitted to a synchronisation protocol. Follicles ≥7mm were measured and follicular wall blood flow evaluated every 12h for approximately 3.5 days until ovulation. After ovulation, cows were scanned daily for 8 days and similar parameters were evaluated for the CL. Blood samples were collected and plasma progesterone concentrations quantified. All parameters were positively correlated. Correlation values ranged from 0.26 to 0.74 on data normalised to ovulation and from 0.31 to 0.74 on data normalised to maximum values. Correlations between calculated ratios of both POF and CL in data normalised to ovulation and to maximum values ranged from moderate (0.57) to strong (0.87). Significant (Pprogesterone concentrations of the resultant CL. These findings indicate that follicle vascularity coordinates CL blood flow and progesterone production in synchronised beef cows.

Circulating NOS3 modulates left ventricular remodeling following reperfused myocardial infarction.

Directory of Open Access Journals (Sweden)

Simone Gorressen

Full Text Available Nitric oxide (NO is constitutively produced and released from the endothelium and several blood cell types by the isoform 3 of the NO synthase (NOS3. We have shown that NO protects against myocardial ischemia/reperfusion (I/R injury and that depletion of circulating NOS3 increases within 24 h of ischemia/reperfusion the size of myocardial infarction (MI in chimeric mice devoid of circulating NOS3. In the current study we hypothesized that circulating NOS3 also affects remodeling of the left ventricle following reperfused MI.To analyze the role of circulating NOS3 we transplanted bone marrow of NOS3-/- and wild type (WT mice into WT mice, producing chimerae expressing NOS3 only in vascular endothelium (BC-/EC+ or in both, blood cells and vascular endothelium (BC+/EC+. Both groups underwent 60 min of coronary occlusion in a closed-chest model of reperfused MI. During the 3 weeks post MI, structural and functional LV remodeling was serially assessed (24 h, 4 d, 1 w, 2 w and 3 w by echocardiography. At 72 hours post MI, gene expression of several extracellular matrix (ECM modifying molecules was determined by quantitative RT-PCR analysis. At 3 weeks post MI, hemodynamics were obtained by pressure catheter, scar size and collagen content were quantified post mortem by Gomori's One-step trichrome staining.Three weeks post MI, LV end-systolic (53.2±5.9 μl; ***p≤0.001; n = 5 and end-diastolic volumes (82.7±5.6 μl; *p<0.05; n = 5 were significantly increased in BC-/EC+, along with decreased LV developed pressure (67.5±1.8 mm Hg; n = 18; ***p≤0.001 and increased scar size/left ventricle (19.5±1.5%; n = 13; **p≤0.01 compared to BC+/EC+ (ESV: 35.6±2.2 μl; EDV: 69.1±2.6 μl n = 8; LVDP: 83.2±3.2 mm Hg; n = 24; scar size/LV13.8±0.7%; n = 16. Myocardial scar of BC-/EC+ was characterized by increased total collagen content (20.2±0.8%; n = 13; ***p≤0.001 compared to BC+/EC+ (15.9±0.5; n = 16, and increased collagen type I and III subtypes

Cine-CT measurement of cortical renal blood flow

International Nuclear Information System (INIS)

Jaschke, W.R.; Gould, R.G.; Cogan, M.G.; Sievers, R.; Lipton, M.J.

1987-01-01

A modified indicator-dilution technique using radiographic contrast material and a cine-CT scanner was used to measure blood flow in the renal cortex of dogs. To validate this technique, CT measurements were correlated with simultaneous measurements of flow determined by radioactive microspheres. Measurements were taken during euvolemic conditions and after hemorrhage. Thirty-nine measurements were compared, covering a flow range from 1 to 7 ml min-1 g-1, and a good correlation was found between the cine-CT and microsphere results (r = 0.93; p less than 0.001). Additionally, cine-CT measurements were made of the mean transit time (MTT) of contrast material through the renal cortex, and the reciprocal of these MTT values was also well correlated to microsphere determined flow (r = 0.94; p less than 0.001). Thus, cine-CT appears to be a promising new technique for measuring renal blood flow

Combination Anti-Apoptotic Effect of Erythropoietin and Melatonin on Ischemia Reperfusion-Induced Renal Injury in Rats

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Shokofeh Banaei

2016-11-01

Full Text Available Renal ischemia-reperfusion (IR contributes to the development of acute renal failure (ARF. Oxygen free radicals are considered to be principal components involved in the pathophysiological tissue alterations observed during renal IR. The purpose of this study was to investigate the combination effect of melatonin (MEL and erythropoietin (EPO, which are a potent antioxidant and anti-apoptotic agents, in IR-induced renal injury in rats. Wistar Albino rats were unilaterally nephrectomized and subjected to 45 min of renal pedicle occlusion followed by 24 h reperfusion. MEL (10 mg/kg, i.p and EPO (5000 U/kg, i.p were administered prior to ischemia. After 24 h reperfusion, following decapitation, blood samples were collected for the determination of superoxide dismutase (SOD, glutathione peroxidase (GPx, and malondialdehyde (MDA levels. Also, renal samples were taken for histological evaluation and apoptosis assay. Ischemia-reperfusion increased SOD, GPx, MDA levels, and TUNEL positive cells. Histopathological findings of the IR group confirmed that there was renal impairment in the tubular epithelium. Treatment with EPO and MEL decreased SOD, GPx, and MDA levels, histopathological changes, and TUNEL positive cells. These results indicated that the combination of MEL and EPO could not exert more nephroprotective and anti-apoptotic effects than MEL treatment in renal ischemia-reperfusion injury.

High-Flow Nasal Cannula Therapy in a Patient with Reperfusion Pulmonary Edema following Percutaneous Transluminal Pulmonary Angioplasty

Directory of Open Access Journals (Sweden)

Kiyoshi Moriyama

2014-01-01

Full Text Available A 62-year-old woman with Wolff-Parkinson-White syndrome was with recent worsening of dyspnea to New York Heart Association functional status Class III. The patient was diagnosed as having central type chronic thromboembolic pulmonary hypertension. By cardiac catheterization, her mean pulmonary artery pressure was 53 mmHg with total pulmonary resistance 2238 dynes·sec·cm−5. After medical therapies with tadalafil, furosemide, ambrisentan, beraprost, and warfarin were initiated, percutaneous transluminal pulmonary angioplasty (PTPA was performed. Following PTPA, life-threating hypoxemia resulting from postoperative reperfusion pulmonary edema developed. High-flow nasal cannula therapy (HFNC was applied, and 100% oxygen at 50 L/min of flow was required to keep oxygenation. HFNC was continued for 3 days, and the patient was discharged on 8th postoperative day with SpO2 of 97% on 3 L/min of oxygen inhalation. Because of the simplicity of the technique, the lower cost of equipment, and remarkable patient tolerance to the treatment, we speculate that HFNC can take over the post of noninvasive ventilation as first-line therapy for patients with acute respiratory failure.

Characterization of Microparticles after Hepatic Ischemia-Reperfusion Injury

Science.gov (United States)

Freeman, Christopher M.; Quillin, Ralph C.; Wilson, Gregory C.; Nojima, Hiroyuki; Johnson, Bobby L.; Sutton, Jeffrey M.; Schuster, Rebecca M.; Blanchard, John; Edwards, Michael J.; Caldwell, Charles C.; Lentsch, Alex B.

2014-01-01

Background Hepatic ischemia-reperfusion (I/R) is a well-studied model of liver injury and has demonstrated a biphasic injury followed by recovery and regeneration. Microparticles (MPs) are a developing field of study and these small membrane bound vesicles have been shown to have effector function in other physiologic and pathologic states. This study was designed to quantify the levels of MPs from various cell origins–platelets, neutrophils, and endolethial cells–following hepatic ischemia-reperfusion injury. Methods A murine model was used with mice undergoing 90 minutes of partial hepatic ischemia followed by various times of reperfusion. Following reperfusion, plasma samples were taken and MPs of various cell origins were labeled and levels were measured using flow cytometry. Additionally, cell specific MPs were further assessed by Annexin V, which stains for the presence of phosphatidylserine, a cell surface marker linked to apoptosis. Statistical analysis was performed using one-way analysis of variance with subsequent Student-Newman-Keuls test with data presented as the mean and standard error of the mean. Results MPs from varying sources show an increase in circulating levels following hepatic I/R injury. However, the timing of the appearance of different MP subtypes differs for each cell type. Platelet and neutrophil-derived MP levels demonstrated an acute elevation following injury whereas endothelial-derived MP levels demonstrated a delayed elevation. Conclusion This is the first study to characterize circulating levels of cell-specific MPs after hepatic I/R injury and suggests that MPs derived from platelets and neutrophils serve as markers of inflammatory injury and may be active participants in this process. In contrast, MPs derived from endothelial cells increase after the injury response during the reparative phase and may be important in angiogenesis that occurs in the regenerating liver. PMID:24879335

The effects of epidural bupivacaine on ischemia/reperfusion-induced liver injury.

Science.gov (United States)

Sarikus, Z; Bedirli, N; Yilmaz, G; Bagriacik, U; Bozkirli, F

2016-01-01

Several animal studies showed beneficial effects of thoracic epidural anesthesia (TEA) in hippocampal, mesenteric and myocardial IR injury (2-4). In this study, we investigated the effects of epidural bupivacaine on hepatic ischemia reperfusion injury in a rat model. Eighteen rats were randomly divided into three groups each containing 6 animals. The rats in Group C had sham laparotomy. The rats in the Group S were subjected to liver IR through laparotomy and 20 mcg/kg/h 0.9% NaCl was administered to these rats via an epidural catheter. The rats in the Group B were subjected to liver IR and were given 20 mcg/kg/h bupivacaine via an epidural catheter. Liver tissue was harvested for MDA analysis, apoptosis and histopathological examination after 60 minutes of ischemia followed by 360 minutes of reperfusion. Blood samples were also collected for TNF-α, IL-1β, AST and ALT analysis. The AST and ALT levels were higher in ischemia and reperfusion group, which received only normal saline via the thoracic epidural catheter, compared to the sham group. In the ischemia reperfusion group, which received bupivacaine via the epidural catheter, IL-1 levels were significantly higher than in the other groups. TNF-α levels were higher in the Groups S and B compared to the sham group. Bupivacaine administration induced apoptosis in all animals. These results showed that thoracic epidural bupivacaine was not a suitable agent for preventing inflammatory response and lipid peroxidation in experimental hepatic IR injury in rats. Moreover, epidural bupivacaine triggered apoptosis in hepatocytes. Further research is needed as there are no studies in literature investigate the effects of epidural bupivacaine on hepatic ischemia reperfusion injury (Tab. 3, Fig. 3, Ref. 34).

Neonatal changes in renal blood flow distribution in puppies

International Nuclear Information System (INIS)

Aschinberg, L.C.; Goldsmith, D.I.; Olbing, H.; Spitzer, A.; Edelmann, C.M. Jr.; Blaufox, M.D.

1975-01-01

The intrarenal distribution of blood flow was studied in 31 newborn mongrel puppies from 18 h to 70 days using xenon washout and krypton autoradiography. Mean renal blood flow increased from 0.39 +- 0.05 ml/g per min (SE) the 1st wk to 2.06 +- 0.12 ml/g per min at 6 wk. During the 1st wk of life the renal cortex was perfused homogeneously at 0.88 +- 0.19 ml/g min (SE) and accounted for 35 +- 4 percent of the renal blood flow. During the 2nd wk a narrow, rapidly perfused zone of outer cortex was identified which was perfused at 3.35 +- 0.26 ml/g per min, received 19.53 +- 5.05 percent of the total renal blood flow, and represented 15 +- 4 percent of the mass of the total cortex. The inner cortex and outer medulla at this time received 53.40 +- 4.12 percent of the flow at 1.07 +- 0.08 ml/g per min. Outer cortical flow increased with age reaching adult values by about 6 to 10 wk when the rapidly perfused area represented 40 +- 8 percent of the cortex. These changes are parallel to the results of previously reported studies with microspheres in newborn puppies and are compatible with the well-established maturational changes noted in neonates of several species. They represent the first gas-washout studies in animals during the first 6 wk of life

Effect of regional heating on the liver blood flow in rats

International Nuclear Information System (INIS)

Nakajima, T.; Song, C.W.; Osborn, J.L.; Rhee, J.G.; Levitt, S.H.

1987-01-01

The authors measured the blood flow in the liver of rats heated with a radio frequency capacitive heating device. The blood flow through the hepatic artery, as measured with the radioactive microsphere method, was 0.21 ml/min/gm; it increased by 13% and 16% when heated for 15 minutes at 41 0 C and 43 0 C, respectively. The portal vein blood flow was 1.09 ml/min/gm and decreased by 12% and 20% on heating for 15 minutes at 41 0 C and 43 0 C, respectively. The total liver blood flow, therefore, decreased by 11% at 41 0 C and by 14% at 43 0 C from the control value of 1.30 ml/min/gm

Radionuclide and dopplergraphic assessment of portal hepatic blood flow in opisthorchiasis

International Nuclear Information System (INIS)

Borodulin, V.G.; Ermolitskij, N.M.; Zavadovskaya, V.D.; Prosekina, N.M.; Borodulin, Yu.V.

1996-01-01

Dynamic studies of the portal blood flow were carried out in 88 patients using colloid radionuclide gold-198 and Tc-99m-phytate and in 84 patients by dopplerography. Radionuclide studies showed that both radiopharmaceutical adequately reflected the portal blood flow in the liver. Portal blood flow values obtained by the duplex echographic method were 0.7 times lower than these estimated by radionuclide indirect angiography. The authors come to a conclusions that the share of the liver in colloid capture should be taken into consideration for the correct estimation of the level of portal hepatic hemodynamics. Portal hepatic blood flow was found markedly reduced in patients with chronic opisthorchiasis in comparison with normal controls, this difference being more expressed in male patients [ru

Decreased chronic-stage cortical C-11-flumazenil binding after focal ischemia-reperfusion in baboons - A marker of selective neuronal loss?

International Nuclear Information System (INIS)

Giffard, C.; Landeau, B.; Kerrouche, N.; Young, A.R.; Giffard, C.; Landeau, B.; Kerrouche, N.; Young, A.R.; Giffard, C.; Landeau, B.; Baron, J.C.

2008-01-01

Background and Purpose - Although the penumbra can be saved by early reperfusion, in the rat it is consistently affected by selective neuronal loss. Mapping selective neuronal loss in the living primate would be desirable. Methods - Five young adult baboons underwent 15 O positron emission tomography for cerebral blood flow, cerebral oxygen consumption, and oxygen extraction fraction mapping at baseline and serially during and after 20-hours temporary middle cerebral artery occlusion. At approximately day 30, 11 C-flumazenil (FMZ), a potential positron emission tomography marker of selective neuronal loss, and structural magnetic resonance-based infarct mapping were obtained, and the brain was perfused-fixed. Reduced FMZ binding in non-infarcted cortical middle cerebral artery areas was searched voxel-wise, and specific binding was assessed using compartmental modeling of FMZ time-activity curves. Results - Visual inspection revealed reduced late FMZ uptake in the affected cortical territory, extending well beyond the infarct. Accordingly, the incidence of selected voxels was greater than chance, documenting mildly but significantly reduced FMZ uptake and specific binding. Serial 15 O positron emission tomography revealed moderately severe acute ischemia followed by reperfusion. Histopathology documented only mild neuronal changes in or near the affected areas. Conclusions - We document moderate but definite late FMZ binding decrements in non-infarcted cortical areas in the baboon, consistent with previous rat and human studies. These were acutely characterized by moderate ischemia followed by reperfusion, consistent with neuronal damage from ischemic or reperfusion injury in the salvaged at-risk tissue. Only mild histopathological changes subtended these FMZ alterations suggesting subtle processes such as isolated dendrite or synapse loss. Whether these changes impact on clinical outcome deserves studying because they may be targeted by specific neuro