CLINICAL AND EXPERIMENTAL PHARMACOLOGY AND PHYSIOLOGY, Issue 5-6 2004
Gabriela A Eppel
Summary 1.,There is strong evidence that the renal medullary circulation plays a key role in long-term blood pressure control. This, and evidence implicating sympathetic overactivity in development of hypertension, provides the need for understanding how sympathetic nerves affect medullary blood flow (MBF). 2.,The precise vascular elements that regulate MBF under physiological conditions are unknown, but likely include the outer medullary portions of descending vasa recta and afferent and efferent arterioles of juxtamedullary glomeruli, all of which receive dense sympathetic innervation. 3.,Many early studies of the impact of sympathetic drive on MBF were flawed, both because of the methods used for measuring MBF and because single and often intense neural stimuli were tested. 4.,Recent studies have established that MBF is less sensitive than cortical blood flow (CBF) to electrical renal nerve stimulation, particularly at low stimulus intensities. Indeed, MBF appears to be refractory to increases in endogenous renal sympathetic nerve activity within the physiological range in all but the most extreme cases. 5.,Multiple mechanisms appear to operate in concert to blunt the impact of sympathetic drive on MBF, including counter-regulatory roles of nitric oxide and perhaps even paradoxical angiotensin II-induced vasodilatation. Regional differences in the geometry of glomerular arterioles are also likely to predispose MBF to be less sensitive than CBF to any given vasoconstrictor stimulus. 6.,Failure of these mechanisms would promote reductions in MBF in response to physiological activation of the renal nerves, which could, in turn, lead to salt and water retention and hypertension. [source]

Perfusion-based functional magnetic resonance imaging,

CONCEPTS IN MAGNETIC RESONANCE, Issue 1 2003
Afonso C. Silva
Abstract The measurement of cerebral blood flow (CBF) is a very important way of assessing tissue viability, metabolism, and function. CBF can be measured noninvasively with magnetic resonance imaging (MRI) by using arterial water as a perfusion tracer. Because of the tight coupling between neural activity and CBF, functional MRI (fMRI) techniques are having a large impact in defining regions of the brain that are activated due to specific stimuli. Among the different fMRI techniques, CBF-based fMRI has the advantages of being specific to tissue signal change, a critical feature for quantitative measurements within and across subjects, and for high-resolution functional mapping. Unlike the conventional blood oxygenation level dependent (BOLD) technique, the CBF change is an excellent index of the magnitude of neural activity change. Thus, CBF-based fMRI is the tool of choice for longitudinal functional imaging studies. A review of the principles and theoretical backgrounds of both continuous and pulsed arterial spin labeling methods for measuring CBF is presented, and a general overview of their current applications in the field of functional brain mapping is provided. In particular, examples of the use of CBF-based fMRI to investigate the fundamental hemodynamic responses induced by neural activity and to determine the signal source of the most commonly used BOLD functional imaging are reviewed. © 2003 Wiley Periodicals, Inc. Concepts Magn Reson 16A: 16,27, 2003 [source]

Myocardial Perfusion As Assessed by Positron Emission Tomography During Long-Term Mechanical Circulatory Support

CONGESTIVE HEART FAILURE, Issue 2 2006
George V. Letsou MD
Although mechanical circulatory support (MCS) can improve myocardial function in patients with advanced heart failure, its effects on relative myocardial perfusion are unclear. Using positron emission tomographic imaging techniques, the authors assessed relative myocardial perfusion in patients with ischemic or idiopathic cardiomyopathy who were receiving chronic MCS with a left ventricular assist device (pulsatile HeartMate [n=2] [Thoratec Corporation, Pleasanton, CA] or nonpulsatile Jarvik 2000 [n=4] [Jarvik Heart, Inc., New York, NY]). Relative myocardial perfusion was compared at lower and higher levels of MCS (50 vs. 100,110 ejections/min for the HeartMate and 8000 vs. 12,000 rpm for the Jarvik 2000). The size and severity of perfusion defects at rest and after dipyridamole stress were measured objectively and subjectively by computer algorithms and visual inspection, respectively. Relative myocardial perfusion increased >5% from baseline in only one of six patients when MCS was increased. No change in relative myocardial perfusion of >5% was seen in any of the other five patients, even after subsequent dipyridamole stress positron emission tomographic imaging. These pilot study findings suggest that the decreased metabolic requirements induced by ventricular unloading correspondingly decreased blood flow requirements to physiologically inactive myocardium. [source]

Nitric oxide counteracts angiotensin II induced contraction in efferent arterioles in mice

ACTA PHYSIOLOGICA, Issue 4 2004
A. Patzak
Abstract Aim:, Efferent arterioles (Ef) are one of the final control elements in glomerular haemodynamics. The influence of nitric oxide (NO) on Ef remains ambiguous. Methods:, To test the hypothesis that endothelial NO plays an important role in this context, afferent arterioles (Af) and Ef of wild-type mice (WT), and Ef of mice lacking the endothelial NO synthetase [eNOS(,/,)] were perfused. Perfusion was performed in Ef via Af (orthograde) as well as from the distal end of Ef (retrograde), which provides an estimate for the importance of substances derived from the glomerulus. Angiotensin II (Ang II) was added in doses ranging from 10,12 to 10,6 mol L,1 to the bath solution. Results:, Ang II reduced the luminal diameter of Af to 68 ± 7 and in Ef to 55 ± 8% during orthograde, and to 35 ± 6% during retrograde perfusion (10,6 mol L,1 Ang II) in WT. Pre-treatment with NG -Nitro- l -arginine-methylester (l -NAME) (10,4 mol L,1) increased the Ang II sensitivity in retrograde (17 ± 9%) and orthograde perfused Ef (19 ± 9%). The Ang II sensitivity was enhanced in eNOS(,/,) mice compared with WT, too. Already at a dose of Ang II 10,9 mol L,1, luminal diameters diminished to 8 ± 7 and 7 ± 4%. Conclusion:, The increased Ang II sensitivity during l -NAME pre-treatment and in eNOS(,/,) mice indicates a strong counteraction of endothelial derived NO on Ang II induced contraction in Ef. Moreover, Ef are similarly sensitive to Ang II during either retrograde or orthograde perfusion in the absence of NO effects, suggesting that NO mediates, at least in part, the action of potential vasodilatory substances from the glomerulus. [source]

In Vivo Perfusion of Human Skin Substitutes With Microvessels Formed by Adult Circulating Endothelial Progenitor Cells

DERMATOLOGIC SURGERY, Issue 2 2008
ELAINE F. KUNG MD
BACKGROUND At present, tissue-engineered human skin substitutes (HSSs) mainly function as temporary bioactive dressings due to inadequate perfusion. Failure to form functional vascular networks within the initial posttransplantation period compromises cell survival of the graft and its long-term viability in the wound bed. OBJECTIVES Our goal was to demonstrate that adult circulating endothelial progenitor cells (EPCs) seeded onto HSS can form functional microvessels capable of graft neovascularization and perfusion. MATERIALS AND METHODS Adult peripheral blood mononuclear cells (PBMCs) underwent CD34 selection and endothelial cell (EC) culture conditions. After in vitro expansion, flow cytometry verified EC phenotype before their incorporation into HSS. After 2 weeks in vivo, immunohistochemical analysis, immunofluorescent microscopy, and microfil polymer perfusion were performed. RESULTS CD34+ PBMCs differentiated into EPC demonstrating characteristic EC morphology and expression of CD31, Tie-2, and E-selectin after TNF,-induction. Numerous human CD31 and Ulex europaeus agglutinin-1 (UEA-1) microvessels within the engineered grafts (HSS/EPCs) inosculated with recipient murine circulation. Limitation of murine CD31 immunoreactivity to HSS margins showed angiogenesis was attributable to human EPC at 2 weeks posttransplantation. Delivery of intravenous rhodamine-conjugated UEA-1 and microfil polymer to HSS/EPCs demonstrated enhanced perfusion by functional microvessels compared to HSS control without EPCs. CONCLUSION We successfully engineered functional microvessels in HSS by incorporating adult circulating EPCs. This autologous EC source can form vascular conduits enabling perfusion and survival of human bioengineered tissues. [source]

Apical Ballooning Syndrome in a Postoperative Patient with Normal Microvascular Perfusion by Myocardial Contrast Echocardiography

ECHOCARDIOGRAPHY, Issue 7 2005
Gautam Ramakrishna M.D.
Apical ballooning syndrome is classically described as transient left ventricular (LV) dysfunction, marked LV akinesia, and normal or near-normal coronary arteries. The etiology is unclear and there is limited information based on case reports and small case series. We describe a 35-year-old woman who underwent surgical hepatectomy and developed apical ballooning syndrome in the postoperative period. The novel use of myocardial contrast echocardiography (MCE) in this setting demonstrated intact microvascular perfusion and lack of coronary flow-limiting abnormalities despite apical akinesis. In select patients with similar clinical presentations, performing MCE is safe and may be pursued as an alternative to invasive coronary angiography. [source]

Design of an Ultrasound Contrast Agent for Myocardial Perfusion

ECHOCARDIOGRAPHY, Issue 2000
Michel Schneider Ph.D.
Myocardial contrast echography (MCE) has been a major research objective in cardiovascular ultrasound for almost two decades. The design of a contrast agent fulfilling the needs of MCE requires taking into consideration a number of points: a basic decision has to be made whether a deposit agent or a free-flowing agent would be more appropriate and whether an agent active at low/medium mechanical index (MI) is preferable to an agent active only at high MI; only a small percentage of the cardiac output enters the coronary microcirculation, which means that highly sensitive bubble detection methods, such as harmonic imaging or pulse inversion, are needed; the low velocity of blood in the microcirculation that leads to extensive bubble destruction during imaging means that intermittent imaging and/or an agent active at low MI is (are) required; the duration of the contrast effect must be sufficient to allow a complete examination and is affected by the rate of contrast administration; the performance of the contrast agent should not be equipment-dependent. The ultimate goal in MCE is to be able to quantify blood flow in the various segments to determine if adequate oxygenation is achieved. Ultrasound-mediated bubble destruction followed by the measurement of bubble replenishment kinetics opens new perspectives for quantification. SonoVue is a free-flowing ultrasound contrast agent made of sulphur hexafluoride microbubbles stabilized by a highly elastic phospholipid monolayer. SonoVue is able to produce myocardial opacification at a wide range of acoustic pressures and in particular at Mis as low as 0.1. Its performance is not equipment-dependent. Good results for myocardial opacification have been observed in all animal species tested (dogs, minipigs, rabbits), using continuous as well as intermittent imaging. Trials are in progress to demonstrate the clinical utility of SonoVue for rest and stress perfusion studies, in particular for the diagnosis of CAD, the detection of myocardial infarction, the assessment of the success of interventions and myocardial viability, and the detection of hibernating myocardium. [source]

Increased infiltration of Chlamydophila pneumoniae in the vessel wall of human veins after perfusion

EUROPEAN JOURNAL OF CLINICAL INVESTIGATION, Issue 7 2008
K. Kupreishvili
ABSTRACT Background Several studies have suggested an association between Chlamydophila pneumoniae (Cp) infection and atherosclerosis. A recent study detected Cp DNA in the saphenous vein of 12% of all patients before bypass grafting and in 38% of failed grafts. We used a system in which human veins were perfused with autologous blood under arterial pressure. Materials and methods, Veins were surplus segments of saphenous veins of coronary artery bypass grafting (CABG) patients. Vein grafts were perfused with the blood of the same patient after CABG procedures. Veins were analysed for Cp -specific membrane protein using immunohistochemical and PCR analysis. Veins were analysed before and after perfusion (up to 4 h). The number of Cp positive cells was then quantified in the vein layers. Results Cp protein was detected within macrophages only. In non-perfused veins, Cp was present in the adventitia in 91% of all patients, in the circular (64%) and longitudinal (23%) layer of the media. No positivity was found in the intima. Perfusion subsequently resulted in a significant increase of Cp positive cells within the circular layer of the media that, however, differed strongly between different patients. Cp DNA was not detected by PCR in those specimens. Conclusion Cp protein was present in 91% of veins, but the number of positive cells differed remarkably between patients. Perfusion of veins resulted in increased infiltration of Cp into the circular layer. These results may point to a putative discriminating role of Cp with respect to graft failure between different patients. [source]

EFNS guideline on neuroimaging in acute stroke.

EUROPEAN JOURNAL OF NEUROLOGY, Issue 12 2006
Report of an EFNS task force
Neuroimaging techniques are necessary for the evaluation of stroke, one of the leading causes of death and neurological impairment in developed countries. The multiplicity of techniques available has increased the complexity of decision making for physicians. We performed a comprehensive review of the literature in English for the period 1965,2005 and critically assessed the relevant publications. The members of the panel reviewed and corrected an initial draft, until a consensus was reached on recommendations stratified according to the European Federation of Neurological Societies (EFNS) criteria. Non-contrast computed tomography (CT) scan is the established imaging procedure for the initial evaluation of stroke patients. However, magnetic resonance imaging (MRI) has a higher sensitivity than CT for the demonstration of infarcted or ischemic areas and depicts well acute and chronic intracerebral hemorrhage. Perfusion and diffusion MRI together with MR angiography (MRA) are very helpful for the acute evaluation of patients with ischemic stroke. MRI and MRA are the recommended techniques for screening cerebral aneurysms and for the diagnosis of cerebral venous thrombosis and arterial dissection. For the non-invasive study of extracranial vessels, MRA is less portable and more expensive than ultrasonography but it has higher sensitivity and specificity for carotid stenosis. Transcranial Doppler is very useful for monitoring arterial reperfusion after thrombolysis, for the diagnosis of intracranial stenosis and of right-to-left shunts, and for monitoring vasospasm after subarachnoid hemorrhage. Currently, single photon emission computed tomography and positron emission tomography have a more limited role in the evaluation of the acute stroke patient. [source]

Endogenous histamine in the medial septum,diagonal band complex increases the release of acetylcholine from the hippocampus: a dual-probe microdialysis study in the freely moving rat

EUROPEAN JOURNAL OF NEUROSCIENCE, Issue 10 2002
Lucia Bacciottini
Abstract The effects of histaminergic ligands on both ACh spontaneous release from the hippocampus and the expression of c-fos in the medial septum,diagonal band (MSA-DB) of freely moving rats were investigated. Because the majority of cholinergic innervation to the hippocampus is provided by MSA-DB neurons, we used the dual-probe microdialysis technique to apply drugs to the MSA-DB and record the induced effects in the projection area. Perfusion of MSA-DB with high-KCl medium strongly stimulated hippocampal ACh release which, conversely, was significantly reduced by intra-MSA-DB administration of tetrodotoxin. Histamine or the H2 receptor agonist dimaprit, applied directly to the hippocampus, failed to alter ACh release. Conversely, perfusion of MSA-DB with these two compounds increased ACh release from the hippocampus. Also, thioperamide and ciproxifan, two H3 receptor antagonists, administered into MSA-DB, increased the release of hippocampal ACh, whereas R-,-methylhistamine, an H3 receptor agonist, produced the opposite effect. The blockade of MSA-DB H2 receptors, caused by local perfusion with the H2 receptor antagonist cimetidine, moderated the spontaneous release of hippocampal ACh and antagonized the facilitation produced by H3 receptor antagonists. Triprolidine, an H1 receptor antagonist, was without effect. Moreover, cells expressing c-fos immunoreactivity were significantly more numerous in ciproxifan- or thioperamide-treated rats than in controls, although no colocalization of anti-c-fos and anti-ChAT immunoreactivity was observed. These results indicate a role for endogenous histamine in modulating the cholinergic tone in the hippocampus. [source]

Increased responsivity of glutamate release from the substantia nigra pars reticulata to striatal NMDA receptor blockade in a model of Parkinson's disease.

EUROPEAN JOURNAL OF NEUROSCIENCE, Issue 5 2000
A dual probe microdialysis study in hemiparkinsonian rats
Abstract Dual probe microdialysis was employed in freely moving 6-hydroxydopamine (6-OHDA) hemilesioned rats to investigate the effects of blockade of N-methyl-D-aspartate (NMDA) receptors in the dorsolateral striatum on glutamate (Glu) release from the ipsilateral substantia nigra pars reticulata (SNr). Perfusion for 60 min with the NMDA antagonist dizocilpine (0.1 and 1 ,m) in the dopamine (DA)-denervated striatum stimulated nigral Glu release (peak effect of 139 ± 7% and 138 ± 9%, respectively). The lower (0.01 ,m) and higher (10 ,m) concentrations were ineffective. In sham-operated rats, dizocilpine failed to affect nigral Glu release up to 1 ,m but induced a prolonged stimulation at 10 ,m (153 ± 9% at the end of perfusion). The present results show that DA-deficiency in the striatum of hemiparkinsonian rats is associated with increased responsivity of nigral Glu release to striatal NMDA receptor blockade. This suggests that changes of NMDA receptor mediated control of the striatofugal pathways occur during Parkinson's disease (PD). [source]

Regional sympathetic denervation affects the relation between canine local myocardial blood flow and oxygen consumption

EXPERIMENTAL PHYSIOLOGY, Issue 3 2007
David J. C. Alders
Myocardial blood flow and oxygen consumption are heterogeneously distributed. Perfusion and myocardial oxygen consumption are closely correlated in the normal heart. It is unknown how this metabolism,perfusion relation is influenced by sympathetic denervation. We investigated this question in seven chloralose-anaesthetized dogs, 3,4 weeks after regional sympathetic denervation of the left circumflex coronary artery area of supply of the left ventricle. Measurements were made of local myocardial blood flow (MBF, in ml min,1 (g dry wt),1), measured with microspheres, and myocardial oxygen consumption (, in ,mol min,1 (g dry wt),1) in the same location, calculated from the 13C spectrum of tissue extracts after intracoronary infusion of 3,13C-lactate. Since both innervated and denervated regions are subject to the same arterial pressure, lower blood flow indicates higher resistance. Mean MBF was 5.56 ml min,1 (g dry wt),1 (heterogeneity of 3.47 ml min,1 (g dry wt),1) innervated, 7.48 ml min,1 (g dry wt),1 (heterogeneity of 3.62 ml min,1 (g dry wt),1) denervated (n.s.). Significant linear relations were found between MBF and of individual samples within the innervated and denervated regions. The slopes of these relations were not significantly different, but the adjusted mean was significantly higher in the denervated regions (+1.92 ml min,1 (g dry wt),1, an increase of 38% of the mean MBF at the pooled mean , P= 0.028, ANCOVA). The ratio (in ml ,mol,1) was significantly higher, being 0.296 ± 0.167 ml ,mol,1 in the denervated region compared with the innervated region, 0.216 ± 0.126 ml ,mol,1, P= 0.0182, Mann,Whitney U test. These results indicate that sympathetic tone under chloralose anaesthesia imposes a moderate vasoconstrictive effect in the myocardium that is not detected by comparison of the mean blood flow or resistance. [source]

Cell shrinkage evoked by Ca2+ -free solution in rat alveolar type II cells: Ca2+ regulation of Na+,H+ exchange

EXPERIMENTAL PHYSIOLOGY, Issue 2 2005
Hitoshi Murao
The effects of intracellular Ca2+ concentration, [Ca2+]i, on the volume of rat alveolar type II cells (AT-II cells) were examined. Perfusion with a Ca2+ -free solution induced shrinkage of the AT-II cell volume in the absence or presence of amiloride (1 ,m, an inhibitor of Na+ channels); however, it did not in the presence of 5-(N -methyl- N -isobutyl)-amiloride (MIA, an inhibitor of Na+,H+ exchange). MIA decreased the volume of AT-II cells. Inhibitors of Cl,,HCO3, exchange, 4,4,-diisothiocyanostilbene-2,2,-disulfonic acid (DIDS) and 4-acetamido-4,-isothiocyanatostilbene-2,2,-disulfonic acid (SITS) also decreased the volume of AT-II cells. This indicates that the cell shrinkage induced by a Ca2+ -free solution is caused by a decrease in NaCl influx via Na+,H+ exchange and Cl,,HCO3, exchange. Addition of ionomycin (1 ,m), in contrast, induced cell swelling when AT-II cells were pretreated with quinine and amiloride. This swelling of the AT-II cells is not detected in the presence of MIA. Intracellular pH (pHi) measurements demonstrated that the Ca2+ -free solution or MIA decreases pHi, and that ionomycin increases it. Ionomycin stimulated the pHi recovery after an acid loading (NH4+ pulse method), which was not noted in MIA-treated AT-II cells. Ionomycin increased [Ca2+]i in fura-2-loaded AT-II cells. In conclusion, the Na+,H+ exchange activities of AT-II cells, which maintain the volume and pHi, are regulated by [Ca2+]i. [source]

Development of an Improved Technique for the Perfusion of the Isolated Caudal Lobe of Sheep Liver

EXPERIMENTAL PHYSIOLOGY, Issue 5 2000
A. M. Ali
The study was designed to develop an improved technique for perfusing the isolated caudal lobe of sheep liver. Twenty caudal lobes were perfused for 3-4 h, in a non-recirculating mode, with Krebs-Henseleit bicarbonate buffer. The perfusion system was designed to give a constant flow. The hepatic viability and functional normality of the perfused lobe were assessed by measuring the perfusion flow rate, pH, K+ efflux, O2 uptake, substrate uptake, gluconeogenesis from propionate and amino acids, and ureagenesis from ammonia and amino acids. Liver tissue was sampled for histological examination, as well as for the determination of liver glycogen and wet: dry weight ratio. The perfusion flow rate and pH were both stable throughout the perfusion. The potassium concentration in the effluent perfusate did not increase during the perfusion, suggesting that there was no loss of viability or hypoxia. The perfused lobe extracted more than 50% of the O2 supply. The rate of oxygen consumption was comparable to the rate reported in vivo. The initial glycogen content was reduced by about 40% after 4 h perfusion. The wet: dry weight ratio was 3.6, consistent with the absence of tissue oedema. Urea production was stimulated when NH4Cl (0.3 mM) was added to the medium but there was no significant increase in urea release when alanine (0.15 mM), glutamine (0.2 mM) or lysine (0.2 mM) was added. Urea production, however, increased by about 171% when a physiological mixture of amino acids was added. Propionate (0.5 mM), alanine and glutamine stimulated glucose production but not lysine or the complete amino acid mixture. Glutamine release was lower than that reported in the rat liver. Changing the direction of flow also revealed an apparent difference between livers from sheep and rats in their metabolism of ammonia. The improved technique offers a simple practical and inexpensive approach to many problems in ruminant physiology and nutritional biochemistry. [source]

Intracellular pH homeostasis in the filamentous fungus Aspergillus niger

FEBS JOURNAL, Issue 14 2002
Stephan J. A. Hesse
Intracellular pH homeostasis in the filamentous fungus Aspergillus niger was measured in real time by 31P NMR during perfusion in the NMR tube of fungal biomass immobilized in Ca2+ -alginate beads. The fungus maintained constant cytoplasmic pH (pHcyt) and vacuolar pH (pHvac) values of 7.6 and 6.2, respectively, when the extracellular pH (pHex) was varied between 1.5 and 7.0 in the presence of citrate. Intracellular metabolism did not collapse until a ,pH over the cytoplasmic membrane of 6.6,6.7 was reached (pHex 0.7,0.8). Maintenance of these large pH differences was possible without increased respiration compared to pHex 5.8. Perfusion in the presence of various hexoses and pentoses (pHex 5.8) revealed that the magnitude of ,pH values over the cytoplasmic and vacuolar membrane could be linked to the carbon catabolite repressing properties of the carbon source. Also, larger ,pH values coincided with a higher degree of respiration and increased accumulation of polyphosphate. Addition of protonophore (carbonyl cyanide m -chlorophenylhydrazone, CCCP) to the perfusion buffer led to decreased ATP levels, increased respiration and a partial (1 µm CCCP), transient (2 µm CCCP) or permanent (10 µm CCCP) collapse of the vacuolar membrane ,pH. Nonlethal levels of the metabolic inhibitor azide (N3,, 0.1 mm) caused a transient decrease in pHcyt that was closely paralleled by a transient vacuolar acidification. Vacuolar H+ influx in response to cytoplasmic acidification, also observed during extreme medium acidification, indicates a role in pH homeostasis for this organelle. Finally, 31P NMR spectra of citric acid producing A. niger mycelium showed that despite a combination of low pHex (1.8) and a high acid-secreting capacity, pHcyt and pHvac values were still well maintained (pH 7.5 and 6.4, respectively). [source]

Ineffective Peripheral Tissue Perfusion: Clinical Validation in Patients With Hypertensive Cardiomiopathy

INTERNATIONAL JOURNAL OF NURSING TERMINOLOGIES AND CLASSIFICATION, Issue 2 2006
Rita de Cassia Gengo de Silva MS
PURPOSE.,To validate defining characteristics of ineffective peripheral tissue perfusion using vasomotor function assessment. METHODS.,Twenty-four patients with hypertensive cardiomiopathy were evaluated for 18 defining characteristics of ineffective peripheral tissue perfusion and underwent vasomotor function assessment with induction of reactive hyperemia, intra-arterial infusion of acetylcholine, and pulse wave velocity measurement. The Student's t test and Kruskall,Wallis test were used to assess the significance of relationships between defining characteristics and vasomotor function data. FINDINGS.,Diminished lower extremity pulses were associated with diminished forearm blood flow during acetylcholine infusion; left ventricular overload, intermittent claudication, and diminished skin moisture were associated with elevated pulse wave velocity values. CONCLUSION.,The defining characteristics of ineffective peripheral tissue perfusion were highly associated with vasomotor function data as "gold standards" for that diagnosis. PRACTICE IMPLICATIONS.,Nurses should be able to accurately assess diminished lower extremity pulses, intermittent claudication, and diminished skin moisture as relevant characteristics of ineffective peripheral tissue perfusion in patients with hypertensive cardiomiopathy. Irrigation Tissulaire Périphérique Inefficace: Validation Clinique Chez les Patients Atteints de Cardiomyopathie Hypertensive BUT.,Valider les caractéristiques de Irrigation tissulaire périphérique inefficace en utilisant l'évaluation de la fonction vasomotrice. MÉTHODES.,Vingt-quatre patients souffrant de cardiomyopathie hypertensive furent évalués au regard des 18 caractéristiques du diagnostic Irrigation vasculaire périphérique inefficace et de la fonction vasomotrice par induction d'une hyperémie réactionnelle, la perfusion intra-artérielle d'acétylcholine, et la mesure de la vélocité de l'onde du pouls. Les tests "Student t et Kruskall,Wallis" furent utilisés pour déterminer l'importance des liens entre les caractéristiques et les valeurs de la fonction vasomotrice. RÉSULTATS.,La diminution des pulsations périphériques des membres inférieurs fut associée à une diminution du flot sanguin pendant la perfusion d'acétylcholine; une surcharge ventriculaire gauche, de la claudication intermittente et une diminution de l'hydratation de la peau furent associées à des valeurs élevées de la vélocité de l'onde du pouls. CONCLUSION.,,Les caractéristiques de Irrigation tissulaire périphérique inefficace qui furent associées de manière significative à la fonction vasomotrice peuvent être considérées comme les "étalons or" de ce diagnostic. IMPLICATIONS POUR LA PRATIQUE.,Les infirmières devraient être capables d'évaluer correctement la diminution des pouls périphériques, la claudication intermittente, et la diminution de l'hydratation de la peau, car ce sont des caractéristiques pertinentes de l'irrigation tissulaire périphérique inefficace chez les patients atteints de cardiomyopathie hypertensive. Translation by Cécile Boisvert, MSN, RN Perfusão Tissular Periférica Ineficaz: Validação Clínica em Pacientes com Miocardiopatia Hipertensiva PROPÓSITO.,Validar as caraterísticas definidoras do diagnóstico de perfusão tissular periférica ineficaz usando a avaliação da função vasomotora. MÉTODO.,Vinte e quatro pacientes com miocardiopatia hipertensiva foram avaliados segundo 18 características definidoras de perfusão tissular periférica ineficaz e submetidos a avaliação da função vasomotora por indução de hiperemia reativa, infusão intra-arterial de acetilcolina e por mensuração da velocidade da onda de pulso. Testes T de Student e de Kruskall,Wallis foram aplicados para avaliar a significância das relações entre as características definidoras e os dados da função vasomotora. RESULTADOS.,Diminuição de pulso nas extremidades inferiores foi associada com o menor fluxo de sangue no antebraço durante a infusão de acetilcolina; sobrecarga ventricular esquerda, claudicação intermitente e diminuição da hidratação da pele foram associados com valores elevados de velocidade de onda de pulso. CONCLUSÃO.,Quatro características definidoras de perfusão tissular periférica ineficaz foram altamente associadas com função vasomotora alterada como "padrão ouro" para este diagnóstico. IMPLICAÇÕES PARA A PRÁTICA.,As enfermeiras devem ser capazes de avaliar com precisão a diminuição dos pulsos das extremidades inferiores, claudicação intermitente e diminuição na hidratação da pele como características definidoras relevantes da perfusão tissular periférica ineficaz em pacientes com miocardiopatia hipertensiva. Translation by Alba Leite de Barros, PhD, RN Perfusión Tisular Periférica Inefectiva: Validación Clínica en Pacientes que Presentan Miocardiopatía Hipertensiva PROPÓSITO.,Validar las características definitorias del diagnóstico Perfusión tisular periférica inefectiva utilizando una valoración de la función vasomotora. METODOLOGÍA.,Veinticuatro pacientes diagnosticados de Miocardiopatía Hipertensiva fueron evaluados con respecto a las 18 características definitorias del diagnóstico Perfusión tisular periférica inefectiva y sometidos a una valoración de la función vasomotora con inducción de Hiperemia reactiva, infusión intra-arterial de acetilcolina, y medida de la velocidad de la onda del pulso. Se utilizaron los análisis estadísticos de t-Student y Kruskall,Wallis para valorar el significado de las relaciones entre las características definitorias y los datos obtenidos de la valoración de la función vasomotora. HALLAZGOS.,Durante la infusión de acetilcolina se detectó disminución de los pulsos en la extremidad inferior relacionado con la disminución del volumen de sangre en el antebrazo; la sobrecarga ventricular izquierda, claudicación intermitente y disminución de la hidratación de la piel fueron asociadas con la elevación de los valores de la velocidad de la onda del pulso. CONCLUSIÓN.,Las características definitorias del diagnóstico Perfusión tisular periférica inefectiva estaban fuertemente asociadas a los datos procedentes de la valoración de la función vasomotora identificándose como "estándares fundamentales" para este diagnóstico. IMPLICACIONES PARA LA PRÁCTICA.,Las enfermeras deberían ser capaces de valorar cuidadosamente la presencia de pulsos disminuidos en las extremidades inferiores, y la disminución de la hidratación de la piel ya que son características relevantes del diagnóstico Perfusión tisular periférica inefectiva en pacientes que presentan Miocardiopatía Hipertensiva. Translation by Adolf Guirao, RN [source]

Evaluation of Interventions Proposed for Altered Tissue Perfusion: Cardiopulmonary in Patients Hospitalized With Acute Myocardial Infarction

INTERNATIONAL JOURNAL OF NURSING TERMINOLOGIES AND CLASSIFICATION, Issue 2003
Ivanise Maria Gomes
PURPOSE To evaluate the effectiveness and efficacy of the interventions proposed for patients with altered tissue perfusion: cardiopulmonary, according to NIC and NOC taxonomies. METHODS Prospective and descriptive study carried out in the cardiology unit of a school hospital with patients under clinical treatment followed from admission until discharge. Patient data were collected using the unit's assessment tool and nursing diagnoses were established. Daily activities were proposed for these patients based on NIC interventions "cardiac care: acute,""cardiac care," and "cardiac care: rehabilitative." Results were evaluated according to indicators selected from NOC's Tissue Perfusion: Cardiac. FINDINGS The sample comprised 25 patients (12 males, 13 females), age range 39 to 83 years. Days hospitalized averaged 3.5 in the coronary unit and 3.5 in the cardiology infirmary, for a total of 7 hospital days. The nursing diagnosis was made based on defining characteristics: enzymatic and ECG changes were found in 100% of the patients, chest pain (96%), diaphoresis (80%), and nausea (72%). The related factor in evidence for 100% of the sample was coronary arterial flow interruption. Patients were evaluated according to NOC outcomes both before starting activities and daily, with the following results: chest pain , 64% of patients initially presented pain with score 1, most (72%) presented scores 4 and 5 on day 2; on days 3, 5, 6, and 7 of hospitalization, all patients reported absence of pain (score 5). On day 4 only, 4% of patients reported pain with intensity 7 (score 2). Profuse diaphoresis was found in 80% of the sample on day 1 of hospitalization, and that disappeared in the course of the remaining days. Nausea was found in 44% of the population with score 1 on day 1 of hospitalization, and disappeared subsequently. Most the patients (84%) did not present with vomiting. Also, no evidence was found of vital sign changes in most of the sample. ECG presented score 1 in 72% of the sample on day 1, greatly decreasing from day 2. Cardiac enzymes appeared in 100% of the sample, decreasing in subsequent days. Heart ejection fraction, pulmonary artery pressure, heart rate, and myocardial scanning indicators were not measured. CONCLUSIONS Indicators evaluated achieved score 5 (no compromise) on hospital discharge in 100% of patients, which evidences effectiveness of the interventions performed. [source]

Perfusion, oxygenation and warming

INTERNATIONAL WOUND JOURNAL, Issue 2007
David Leaper
Abstract Perfusion, oxygenation and warming are three elements which have a significant effect on wound healing both with respect to speed and quality of healing. The effects include infection control, increased blood flow and improved quality of granulation tissue. The importance of these elements are outlined and discussed to provide and introduce the importance of oxygen in the healing process. [source]

Bilateral Axillary Artery Perfusion to Reduce Brain Damage during Cardiopulmonary Bypass

JOURNAL OF CARDIAC SURGERY, Issue 2 2010
Kazuhiro Kurisu M.D.
The aim of the present study was to examine the value of bilateral axillary artery perfusion during thoracic aortic and cardiac surgery, and to evaluate the clinical results with a particular focus on cerebral damage. Methods: From March 2002 through December 2007, 24 patients (16 male and eight female; age range, 43 to 84 years) underwent bilateral axillary artery perfusion through side grafts during cardiopulmonary bypass. Aortic surgery, including total arch replacement, hemiarch replacement, and ascending aortic replacement, was performed in 21 patients. Bilateral axillary artery perfusion was also used in three complicated valve surgeries after expanding its indication to cardiac pathology with a diseased aorta, two redo cases with severe atherosclerotic vascular disease, and one case with a porcelain aorta. Results: Bilateral axillary artery perfusion was successful in all patients. There were no complications related to this procedure except in one patient, who suffered from a local fluid retention in one wound, requiring puncture drainage. There was no hospital mortality. No strokes were identified by either clinical assessments or diagnostic imaging. Conclusions: Bilateral axillary artery perfusion is a useful method for protection of the brain during either thoracic aortic or cardiac surgery when the patients have an extensively diseased aorta.,(J Card Surg 2010;25:139-142) [source]

Immediate Clinical Outcome after Prolonged Periods of Brain Protection: Retrospective Comparison of Hypothermic Circulatory Arrest, Retrograde, and Antegrade Perfusion

JOURNAL OF CARDIAC SURGERY, Issue 5 2009
Anil Z. Apaydin M.D.
Methods: Between 1993 and 2006, 339 patients underwent proximal aortic operations using a period of cerebral protection. Among these, 161 patients (mean age of 55 ± 12 years) who required cerebral protection longer than 25 minutes were included in the analysis. Ascending aorta with or without root was replaced in all patients. In addition, total arch replacement was performed in 36 patients. All patients were cooled to rectal temperature of 16 °C. Hypothermic circulatory arrest without adjunctive perfusion was used in 48 patients. Retrograde or antegrade cerebral perfusion was added in 94 and 19 patients, respectively. The mean duration of total cerebral protection was 42 ± 17 minutes. Results: Overall mortality was 15.5% (25/161) and did not differ among the perfusion groups. There was no difference in the incidence of overall neurological events, temporary neurological dysfunction, or major stroke among the groups. Multivariate analysis revealed that transfusion of >3 units of blood (p < 0.03) was an incremental risk factor for mortality. History of hypertension (p < 0.03), coexisting systemic diseases (p < 0.005), and transfusion of >3 units of blood (p < 0.04) were predictors of temporary neurological dysfunction. Conclusion: In proximal aortic operations requiring prolonged periods of cerebral protection, the mortality and neurological morbidity are not determined by the type of cerebral protection method only. Factors like hypertension and diabetes may play a role in the development of temporary neurological dysfunction. [source]

Noninvasive Control of Adequate Cerebral Oxygenation During Low-Flow Antegrade Selective Cerebral Perfusion on Adults and Infants in the Aortic Arch Surgery

JOURNAL OF CARDIAC SURGERY, Issue 5 2008
Álvaro Rubio M.D.
Background: Aortic arch repair techniques using low-flow antegrade selective cerebral perfusion have been standardized to a certain degree. However, some of the often-stated beneficial effects have never been proven. Especially, the existence of an adequate continuous flow in both cerebral hemispheres during the surgical procedure still remains unclear as the monitoring of an effective perfusion remains a nonstandardized technique. Methods: Seventeen patients underwent surgical reconstruction of the aortic arch due to aortic aneurysm surgery (adult group n = 8 patients) or of the hypoplastic aortic arch due to hypoplastic left heart syndrome (HLHS) or aortic coarctation (infant group n = 9 patients) under general anesthesia and mild hypothermia (adult group 28 °C; infant group 25 °C). Mean weights were 92.75 ± 14.00 kg and 4.29 ± 1.32 kg, and mean ages were 58.25 ± 10.19 years and 55.67 ± 51.11 days in the adult group and the infant group, respectively. The cerebral O2 saturation measurement was performed by continuous plotting of the somatic reflectance oximetry of the frontal regional tissue on both cerebral hemispheres (rSO2, INVOS®; Somanetics Corporation, Troy, MI, USA). Results: During low-flow antegrade perfusion via innominate artery, continuous plots with similar values of O2 saturation (rSO2) in both cerebral hemispheres were observed, whereas a decrease in the rSO2 values below the desaturation threshold correlated with a displacement or an incorrect positioning of the arterial cannula in the right subclavian artery. Conclusions: Continuous monitorization of the cerebral O2 saturation during aortic arch surgery in adults and infants is a feasible technique to control an adequate cannula positioning and to optimize clinical outcomes avoiding neurological complications related to cerebral malperfusion. [source]

Surgery for Cardiac Valves and Aortic Root Without Cardioplegic Arrest ("Beating Heart"): Experience with a New Method of Myocardial Perfusion

JOURNAL OF CARDIAC SURGERY, Issue 6 2007
Tomas A. Salerno M.D.
Similarly, beating heart mitral valve surgery via the trans-septal approach with the aorta unclamped, is a novel technique. We, herein, report a series of 346 patients with a variety of cardiac pathologies who were operated upon utilizing a new modality of myocardial perfusion. Among this group of patients, there were 55 patients who were diagnosed with endocarditis of one or more valves. These patients were excluded from this series of patients. Mean age was 59 ± 12, and there were 196 (67.3%) males and 95 (32.7%) females. There were six aortic root procedures, 90 mitral valve replacements (MVR), 46 mitral valve repairs, 20 MVR+ coronary artery bypass grafting (CABG), 28 tricuspid valve repairs, 106 aortic valve replacements (AVR), 17 AVR+CABG, and 8 AVR/MVR. Crude mortality for the group was 20 of 291 (6.8%). Intra-aortic balloon pump utilization at time of weaning from cardiopulmonary bypass was 6/291 (2.06%), and re-operation for bleeding was needed in 12 of 291 (4.1%) patients. Postoperative stroke occurred in 4 of 291 (1.3%) patients. In these patients, the clinical diagnosis of stroke was made prior to surgery. This initial experience with this new method of myocardial perfusion indicates that results are at least comparable, if not superior, to conventional techniques utilizing intermittent cold blood cardioplegia. [source]

A Simple Technique of Distal Limb Perfusion During Prolonged Femoro-Femoral Cannulation

JOURNAL OF CARDIAC SURGERY, Issue 2 2006
Navid Madershahian M.D.
A serious complication of prolonged femoral cannulation remains the ischemic injury of the distal limb. Subjects: To minimize the incidence of ischemia in the cannulated leg, we have begun to provide antegrade femoral blood flow by placing a vascular introducer percutaneously distal to the arterial cannula into the superficial femoral artery and connecting it to the side port of the arterial line. Conclusion: This technique of distal limb perfusion was found to be safe and effective in preventing lower limb ischemia for patients with prolonged femoral cannulation for extracorporeal circulatory support. [source]

Is It Safe to Initiate Selective Cerebral Perfusion with Normothermia?

JOURNAL OF CARDIAC SURGERY, Issue 5 2005
Mizuho Imamaki M.D.
Cerebral circulation is isolated from systemic circulation to avoid cerebral embolization due to detachment of atherosclerotic material from the aorta, caused by the "sandblasting" effect of high-velocity jets of blood exiting the aortic cannula. However, neither the safety of SCP at normothermia nor the influence of extended SCP time has been sufficiently clarified. To clarify the safety of P-SCP, the comparison study of P-SCP and conventional SCP (C-SCP) was performed retrospectively. Methods: Fifty-seven patients (C-SCP group: 29 patients; P-SCP: 28 patients) underwent surgery between 1992 and 2002. Results: Nine (15.8%) in-hospital death occurred; 4 in the C-SCP group (13.8%) and 5 in the P-SCP group (17.9%) (NS). The SCP time was 136.6 ± 68.5 minutes in the C-SCP group and 195.8 ± 30.7 minutes in the P-SCP group (p < 0.05). One patient in each group exhibited postoperative neurological dysfunction. Conclusion: It may be little dangerous to initiate the SCP with normothermia. P-SCP may be useful in cases in which there is pedunculated atherosclerotic material, or mural thrombus in the ascending and arch aorta. [source]

Emergency Off-Pump Coronary Artery Bypass (OPCAB) for Left Main Coronary Occlusion Using Rapid Aorto-Coronary Perfusion

JOURNAL OF CARDIAC SURGERY, Issue 6 2002
Paul Kerr D.O.
LAD grafted with sapenous vein and immediate aorto-coronary perfusion. Circumflex grafted and patient taken to ICU. Patient discharged on POD #6 after echo shows normal ventricular with no wall motion abnormality. [source]

Book review: Clinical MR Neuroimaging: Diffusion, Perfusion, and Spectroscopy

JOURNAL OF MAGNETIC RESONANCE IMAGING, Issue 2 2006
Jay J. Pillai MD
[source]

Cerebral Hemodynamics Changes During Retrograde Brain Perfusion in Dogs

JOURNAL OF NEUROIMAGING, Issue 2 2001
Alexander Y. Razumovsky PhD
ABSTRACT The objective of this study was to examine cerebral hemodynamics changes during hypothermic circulatory arrest (HCA) with and without retrograde cerebral perfusion (RCP). Thirteen colony-bred hound dogs were placed on cardiopulmonary bypass (CPB) and cooled to 18°C. Five dogs underwent 2 hours of HCA without RCP and 8 with RCP. The animals were then rewarmed on CPB until normothermic and weaned. Cerebral blood flow velocity (CBFV) and Gosling Pulsatility Index (PI) in the middle cerebral artery (MCA) were studied using transcranial Doppler (TCD) ultrasound. At baseline and during pre- and postarrest CPB, there was anterograde direction of blood flow in the MCA. During HCA with RCP, there was retrograde direction of blood flow in the MCA. There was no difference in CBFV between pre-, during, and postarrest CPB in the group with RCP; however, there was significantly increased CBFV during postarrest CPB in the group without RCP compared to the dogs with RCP. Later, at 3 hours after postarrest CPB, there was decreased CBFV in all animals accompanied by increased PI (2.4 ± 0.4 and 2.2 ± 0.6 for animals with RCP and without RCP, respectively) and abnormal TCD waveform changes including decreased diastolic compartment and sharp systolic peak. During hypothermic circulatory arrest, RCP provides CBFV in the MCA comparable to MCA CBFV during CPB. HCA dogs without RCP showed immediate hyperemia on reperfusion. The decreased CBFV and increased PI at 1 hour after postarrest CPB could be an indicator of progressive ischemic injury due to the increased intracranial pressure despite the implementation of RCP. [source]

Melatonin disrupts circadian rhythms of glutamate and GABA in the neostriatum of the awake rat: a microdialysis study

JOURNAL OF PINEAL RESEARCH, Issue 4 2000
B. Marquez de Prado
The purpose of this study was to investigate possible circadian changes in extracellular concentrations of glutamate (GLU) and ,-aminobutyric acid (GABA), and the influence of melatonin on the levels of these neurotransmitters in the neostriatum of awake rats using in vivo microdialysis. At the same time, the concentrations of the amino acids taurine (TAU), glutamine (GLN) and arginine (ARG), as well as dopamine (DA) and its metabolites 3, 4-dihydroxyphenyl acetic acid (DOPAC) and homovanillic acid (HVA), were measured in the extracellular fluid. When dialysates were collected over a 24-hr period (6 hr dark, 12 hr light, 6 hr dark), both GLU and GABA, without the infusion of melatonin, exhibited statistically significant rhythms, with higher levels of these constituents during the dark and lower levels during the day. Perfusion with melatonin (for 19 consecutive hours) prevented the daytime reductions in both GLU and GABA. Of the amino acids measured in the dialysates collected from the neostriatum of non-perfused rats, only ARG exhibited a significant change during the light:dark cycle; again, lowest concentrations were measured during the day. While melatonin perfusion did not statistically significantly influence neostriatal levels of TAU and ARG, GLN levels continued to drop during the infusion of the indoleamine. Dialysate concentrations of DA, DOPAC and HVA exhibited circadian rhythms which were not influenced by melatonin perfusion. The findings indicate there are differential effects of melatonin on extracellular neurotransmitter concentrations in the neostriatum of the awake rat. The results also suggest that the day:night variations in GLU and GABA may relate to daily changes in endogenous melatonin production, while DA and its metabolites are minimally influenced by this secretory product. [source]

Glycine Receptors Involved in Acamprosate's Modulation of Accumbal Dopamine Levels: An In Vivo Microdialysis Study

ALCOHOLISM, Issue 1 2010
PeiPei Chau
Background:, Glycine receptors (GlyRs) in the nucleus accumbens (nAc) and nicotinic acetylcholine receptors (nAChRs) in the ventral tegmental area (VTA) have been suggested to be involved in the positive reinforcing and dopamine elevating effects of ethanol. Recent studies have also shown that ethanol high-preferring rats substantially decrease their ethanol intake when treated with a glycine transporter 1 inhibitor (ORG 25935). Acamprosate, a drug used for relapse prevention in treatment of alcohol dependence, has also been demonstrated to elevate extracellular dopamine levels in the nAc. However, the underlying mechanism of action of acamprosate is not fully understood. Here we investigated whether acamprosate interferes with a neuronal circuitry that previously has been demonstrated to be involved in the dopamine elevating effects of ethanol and taurine. Methods:, In vivo microdialysis in freely moving rats was used to assess accumbal dopamine levels before and during local (nAc) or systemic administration of acamprosate. Results:, Perfusion of 0.5 mM acamprosate in the nAc significantly increased dopamine levels. Pretreatment either with 10 ,M strychnine in the nAc or 100 ,M mecamylamine in the VTA, completely antagonized the acamprosate-induced elevation of accumbal dopamine levels. Also, systemic acamprosate administration elevated accumbal dopamine output, an effect that was abolished by local (nAc) pretreatment with 10 ,M strychnine. Conclusions:, These results suggest that both systemic and local application of acamprosate elevate extracellular dopamine levels in the nAc by activating accumbal GlyRs, and, secondarily, tegmental nAChRs. [source]

Normal cerebral perfusion measurements using arterial spin labeling: Reproducibility, stability, and age and gender effects

MAGNETIC RESONANCE IN MEDICINE, Issue 4 2004
Laura M. Parkes
Abstract Before meaningful conclusions can be drawn from clinical measures of cerebral blood perfusion, the precision of the measurement must be determined and set in the context of inter- and intrasubject sources of variability. This work establishes the reproducibility of perfusion measurements using the noninvasive MRI technique of continuous arterial spin labeling (CASL). Perfusion was measured in 34 healthy normal subjects. Intersubject variability was assessed, and age and gender contributions were estimated. Intersubject variation was found to be large, with up to 100% perfusion difference for subjects of the same age and gender. Repeated measurements in one subject showed that perfusion remains remarkably stable in the short term when compared with intersubject variation and the large capacity for perfusion change in the brain. A significant decrease in the ratio of gray-matter to white-matter perfusion was found with increasing age (0.79% per year (P < 0.0005)). This appears to be due mainly to a reduction in gray-matter perfusion, which was found to decrease by 0.45% per year (P = 0.04). Regional analysis suggested that the gray-matter age-related changes were predominantly localized in the frontal cortex. Whole-brain perfusion was 13% higher (P = 0.02) in females compared to males. Magn Reson Med 51:736,743, 2004. © 2004 Wiley-Liss, Inc. [source]