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Wang Y, Zhong F, Sun N, Xu Z, Li J, Liu Q, Li Z, Zuo Z, Hu S. High-speed multi-parametric photoacoustic microscopy of cerebral hemodynamic and metabolic responses to acute hemodilution. OPTICS LETTERS 2022; 47:1988-1991. [PMID: 35427318 DOI: 10.1364/ol.444327] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Accepted: 03/02/2022] [Indexed: 06/14/2023]
Abstract
The ability of hemodilution to improve vascular circulatory impairment has been demonstrated. However, the effects of acute hemodilution on cerebral hemodynamics and oxygen metabolism have not been assessed at the microscopic level, due to technical limitations. To fill this void, we have developed a new, to the best of our knowledge, photoacoustic microscopy system, which enables high-speed imaging of blood hemoglobin concentration, oxygenation, flow, and oxygen metabolism in vivo. The system performance was examined in both phantoms and the awake mouse brain. This new technique enabled wide-field (4.5 × 3 mm2) multi-parametric imaging of the mouse cortex at 1 frame/min. Narrowing the field of view to 1.5 × 1.5 mm2 allowed dynamic imaging of the cerebral hemodynamic and metabolic responses to acute hypervolemic hemodilution at 6 frames/min. Quantitative analysis of the hemodilution-induced cerebrovascular responses over time showed rapid increases in the vessel diameter (within 50-210 s) and blood flow (50-210 s), as well as decreases in the hemoglobin concentration (10-480 s) and metabolic rate of oxygen (20-480 s) after the acute hemodilution, followed by a gradual recovery to the baseline levels in 1440 s. Providing comprehensive insights into dynamic changes of the cerebrovascular structure and function in vivo, this technique opens new opportunities for mechanistic studies of acute brain diseases or responses to various stimuli.
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Hai J, Lin Q, Deng DF, Pan QG, Ding MX. The pre-treatment effect on brain injury during restoration of normal perfusion pressure with hemodilution in a new rat model of chronic cerebral hypoperfusion. Neurol Res 2013; 29:583-7. [PMID: 17535558 DOI: 10.1179/016164107x166254] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
OBJECTIVES To investigate the effect of hemodilution with high-concentration human serum albumin (HSA) on brain injury in a rat model of chronic cerebral hypoperfusion associated with arteriovenous malformations. METHODS The animal model was established by creating a fistula through an end-to-side anastomosis between the right distal external jugular vein and the ipsilateral common carotid artery, followed by ligation of the left vein draining the transverse sinus and bilateral external carotid arteries. The agent (20% HSA) or control solution (0.9% sodium chloride) was administered intravenously at a dosage of 1% body weight 24 hours before ligation of the fistula. Blood-brain barrier (BBB) disruption was judged by extravasation of Evans blue (EB) dye. EB, water content and the changes of myeloperoxidase (MPO) activity and superoxide dismutase (SOD) activity in rat brains 24 hours after ligation of the fistula were determined. RESULTS EB and water content in rat brains of the pre-treated group were significantly decreased compared with the control group accompanied by reduction of MPO activity and enhancement of SOD activity. DISCUSSION Hemodilution with high-concentration HSA has a certain pre-treatment effect on brain injury after ligation of the fistula in rat model of chronic cerebral hypoperfusion, which may be resulted from improved microcirculation, decrease in inflammatory cell infiltration and inactivation of oxygen free radicals.
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Affiliation(s)
- Jian Hai
- Department of Neurosurgery, Tongji Hospital, Tongji University, 389 XinCun Rd, Shanghai 200065, China.
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3
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Abstract
Heparin has long been known to possess biological effects that are unrelated to its anticoagulant activity. In particular, much emphasis has been placed upon heparin, or novel agents based upon the heparin template, as potential anti-inflammatory agents. Moreover, heparin has been reported to possess clinical benefit in humans, including in chronic inflammatory diseases and cancer, that are over and above the expected effects on blood coagulation and which in many cases are entirely separable from this role. This chapter aims to provide an overview of the non-anticoagulant effects that have been ascribed to heparin, from those involving the binding and inhibition of specific mediators involved in the inflammatory process to effects in whole system models of disease, with reference to the effects of heparin that have been reported to date in human diseases.
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Affiliation(s)
- Rebecca Lever
- The School of Pharmacy, University of London, London, UK.
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Sacco S, Marini C, Olivieri L, Pistoia F, Carolei A. Contribution of Hematocrit to Early Mortality after Ischemic Stroke. Eur Neurol 2007; 58:233-8. [PMID: 17827968 DOI: 10.1159/000107946] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2007] [Accepted: 03/22/2007] [Indexed: 11/19/2022]
Abstract
BACKGROUND Only a few non-recent studies assessed the importance of hematocrit (HCT) in patients with ischemic stroke. We evaluated how HCT might affect early mortality after stroke. METHODS We investigated all first-ever ischemic strokes included in the population-based L'Aquila registry. 3,481 patients according to HCT (%) values were included into four categories (<or=40, 41-45, 46-50, and >50). RESULTS There were more men than women with HCT >50 (6.6 vs. 2.8%; p < 0.0001) and more women than men with HCT <or=40 (48.5 vs. 37.9%; p < 0.0001). Proportions of chronic atrial fibrillation (p = 0.0053) increased in women from the lower to the higher HCT categories. 7- and 28-day case-fatality rates were similar in men and women in the lower HCT categories but higher in women than in men in the higher categories. At the 28-day Kaplan-Meier analysis, men had similar survivals in the different categories while women with HCT >50 showed the worst survival (p < 0.0001). At the multivariate Cox regression analysis HCT 46-50 and >50 was an independent predictor of mortality in women within 28 days. CONCLUSION High HCT might represent in women a previously underestimated independent predictor of mortality after ischemic stroke. Consideration of HCT in future stroke trials would be useful for ameliorating stroke care, especially in women.
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Affiliation(s)
- Simona Sacco
- Department of Neurology, University of L'Aquila, L'Aquila, Italy
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Hochart H, Jenkins PV, Smith OP, White B. Low-molecular weight and unfractionated heparins induce a downregulation of inflammation: decreased levels of proinflammatory cytokines and nuclear factor-kappaB in LPS-stimulated human monocytes. Br J Haematol 2006; 133:62-7. [PMID: 16512830 DOI: 10.1111/j.1365-2141.2006.05959.x] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Unfractionated heparin (UFH) and low-molecular weight heparin (LMWH) are well defined anticoagulant agents. Recent data suggest that both LMWH and UFH may also have potent anti-inflammatory properties; however, their mechanism of action responsible for the anti-inflammatory effect is not yet fully elucidated. This study was designed to assess the effect of LMWH and UFH on human monocytes production of inflammatory markers and nuclear translocation of nuclear factor (NF)-kappaB. Cultured monocytes were pretreated for 15 min with LMWH or UFH (10 microg and 1 microg/million cells) before stimulation with lipopolysaccharide (LPS) at a dose of 1 ng/million cells. Proinflammatory cytokines tumour necrosis factor (TNF)-alpha, interleukin (IL)-8, IL-6 and IL-1beta release were subsequently measured by enzyme-linked immunosorbent assay at 6 h, and nuclear translocation of the proinflammatory NF-kappaB was assessed at 2 h. Treatment with pharmacological doses of LMWH and UFH significantly attenuated LPS-induced production of TNF-alpha, IL-8, IL-6 and IL-1beta as well as NF-kappaB translocation. These results indicate equivalent and significant heparin anti-inflammatory properties at low doses on monocyte-mediated immune response. The inhibition of NF-kappaB activation certainly represents one of the mechanisms by which heparin exerts its anti-inflammatory effect. LMWH and UFH therefore appear as potential therapeutic inhibitors of inflammation.
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Affiliation(s)
- Hélène Hochart
- Thrombosis and Haemostasis Research Group, Institute of Molecular Medicine, Trinity Centre for Health Sciences, Trinity College Dublin, St James's Hospital, Dublin, Ireland.
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Koch S, Concha M, Wazzan T, Romano JG, Forteza A. High dose human serum albumin for the treatment of acute ischemic stroke: a safety study. Neurocrit Care 2006; 1:335-41. [PMID: 16174931 DOI: 10.1385/ncc:1:3:335] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
INTRODUCTION In animal models of focal cerebral ischemia, albumin infusions at doses ranging from 0.6 to 2.5 g/kg are neuroprotective. It is not known whether patients with stroke, often elderly and with underlying cardiovascular disease, can safely tolerate such degrees of volume expansion. Therefore, we retrospectively reviewed the safety of high-dose albumin treatment in patients with acute ischemic stroke. MATERIALS AND METHODS Within 24 hours of ischemic stroke onset, patients who received at least 0.7 g/kg albumin were identified by a review of medical records. Each albumin recipient was assigned two control patients, who received standard fluid management. Controls were matched by age, number of stroke risk factors, stroke severity, and stroke subtype. Medical records were reviewed for treatment-related adverse events, defined as cardiopulmonary complications and mortality. RESULTS Thirty cases (mean age 62.9+/-11.4 years) and 60 controls (mean age 62.5+/-11.8 years) were identified between July 1999 and November 2001. The two groups were evenly matched. The mean dose of albumin infusion was 171 g (2.4 g/kg). Cardiopulmonary complications or death developed in 37% of cases and 18% of controls (p=0.056). Mortality was 7% in both groups. Multivariate regression analysis showed that a history of congestive heart failure and higher total albumin dose were independently associated with the occurrence of adverse events. CONCLUSION Albumin treatment was associated with a nonsignificant trend toward increased cardiopulmonary adverse events. However, these adverse events did not result in excess mortality.
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Affiliation(s)
- Sebastian Koch
- Division of Cerebrovascular Disease, Department of Neurology, University of Miami, FL 33136, USA.
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Handel TM, Johnson Z, Crown SE, Lau EK, Proudfoot AE. Regulation of protein function by glycosaminoglycans--as exemplified by chemokines. Annu Rev Biochem 2005; 74:385-410. [PMID: 15952892 DOI: 10.1146/annurev.biochem.72.121801.161747] [Citation(s) in RCA: 385] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Immune modulators such as cytokines and growth factors exert their biological activity through high-affinity interactions with cell-surface receptors, thereby activating specific signaling pathways. However, many of these molecules also participate in low-affinity interactions with another class of molecules, referred to as proteoglycans. Proteoglycans consist of a protein core to which glycosaminoglycan (GAG) chains are attached. The GAGs are long, linear, sulfated, and highly charged heterogeneous polysaccharides that are expressed throughout the body in different forms, depending on the developmental or pathological state of the organ/organism. They participate in many biological functions, including organogenesis and growth control, cell adhesion, signaling, inflammation, tumorigenesis, and interactions with pathogens. Recently, it was demonstrated that certain chemokines require interactions with GAGs for their in vivo function. The GAG interaction is thought to provide a mechanism for retaining chemokines on cell surfaces, facilitating the formation of chemokine gradients. These gradients serve as directional cues to guide the migration of the appropriate cells in the context of their inflammatory, developmental, and homeostatic functions. In this review, we discuss GAGs and their interaction with proteins, with a special emphasis on the chemokine system.
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Affiliation(s)
- T M Handel
- Department of Molecular and Cell Biology, University of California, Berkeley, California 94720, USA.
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Homi HM, Yang H, Pearlstein RD, Grocott HP. Hemodilution During Cardiopulmonary Bypass Increases Cerebral Infarct Volume After Middle Cerebral Artery Occlusion in Rats. Anesth Analg 2004; 99:974-981. [PMID: 15385336 DOI: 10.1213/01.ane.0000131504.90754.d0] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Although the optimal hematocrit during cardiopulmonary bypass (CPB) is not defined, excessive hemodilution may lead to organ ischemia via a reduction in oxygen-carrying capacity uncompensated by autoregulatory and/or rheologic increases in organ blood flow. As a result, the consequences of hemodilution in patients at risk for cerebral ischemia are not clearly understood. We designed this study to evaluate the effects of hemodilution in the setting of focal cerebral ischemia during CPB. Wistar rats surgically prepared for CPB were randomized to either hemodilution (hemoglobin (Hb), 6 g/dL; n = 9) or control (Hb, 11 g/dL; n = 8) groups and subsequently exposed to focal cerebral ischemia induced by middle cerebral artery occlusion (MCAO). Immediately after the onset of MCAO (maintained for 90 min), 65 min of hypothermic (28 degrees C) CPB was initiated. Twenty-four hours later, functional neurological outcome and cerebral infarct volume were determined. Compared with controls, the hemodilution group had worse neurological performance (new score = 8 [2], hemodilution; versus 10 [2], control; P = 0.030) and larger total cerebral infarct volumes (182 +/- 84 mm(3), hemodilution; versus 103 +/- 58 mm(3), control; P = 0.043). In this experimental model of CPB with reversible MCAO-induced focal cerebral ischemia, hemodilution worsened neurological function and increased cerebral infarct volume.
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Affiliation(s)
- H Mayumi Homi
- Departments of *Surgery and †Anesthesiology (Multidisciplinary Neuroprotection Laboratories), Duke University Medical Center, Durham, North Carolina
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Abstract
The most important adaptive responses from a physiological stance involved the cardiovascular system, consisting in particular of elevation of the cardiac output and its redistribution to favor the coronary and cerebral circulations, at the expense of the splanchnic vascular beds. The evidence regarding these physiological responses, especially in experimental studies that permit the control of many variables, is particularly powerful and convincing. On the other hand, there is a remarkable lack, in quality and quantity, of clinical studies addressing how normal physiological adaptive responses may be affected by a variety of diseases and conditions that often accompany and may complicate anemia, and interactions with other such compounding variables as age and different patient populations. For these reasons, it is not possible to offer guidelines on how to increase, maintain, or even to determine optimal DO2 in high-risk patients and how best transfusion strategies might be used under these conditions. From the brief review of physiological principles and the strong consensus in the literature, it is evident that cardiac function must be a central consideration in decisions regarding transfusion in anemia, because of the critical role it plays in assuring adequate oxygen supply of all vital tissues. Particular attention should be paid to the possible presence of CAD or incipient or cardiac failure, as these conditions may require careful transfusions to improve DO2 at levels that may not necessitate such interventions when cardiac disease is absent. Although the cerebral circulation also serves an obligate aerobic organ unable to tolerate significant hypoxia, there is little convincing evidence to support the notion that cerebral ischemia is aggravated by anemia and that this can be prevented by improved DO2 through rapid correction of anemia. Consequently, the arguments favoring transfusions in the presence of ischemic heart disease do not appear to apply to occlusive cerebrovascular disease. Because firm evidence is lacking on the interactions of concurrent diseases and anemia in various patient populations, understanding of the physiological consequences of anemia, and of the diseases concerned, is useful but not fully sufficient to provide firm and rational guidance to transfusion practice in specific complex clinical instances. A good deal of clinical and experimental investigation is required to support fully rational and comprehensive guidelines. In the meantime, prudent and conservative management, based on awareness of risks and sound understanding of the normal and pathological physiology, must remain the guiding principle.
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Affiliation(s)
- Paul C Hébert
- Centre for Transfusion Research, Clinical Epidemiology Program, Ottawa Health Research Institute, University of Ottawa, Ontario, Canada.
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Ter Minassian A. [Treatment of cerebral oedema]. ANNALES FRANCAISES D'ANESTHESIE ET DE REANIMATION 2003; 22:336-48. [PMID: 12818327 DOI: 10.1016/s0750-7658(03)00056-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Progress in brain imaging, monitoring and physiopathology allows the identification of brain oedema from brain swelling, determination of its interstitial or intracellular nature, as well as blood-brain barrier permeability and the evaluation of the impact on cerebral haemodynamic. Common treatment of all types of cerebral oedema is based on prevention of self-sustained disorders due to increased intracranial pressure resulting in ischemic cerebral oedema. The specific treatment of each type of cerebral oedema is reviewed. Optimization of conventional anti-oedematous strategies is based on the precise determination of the nature of the cerebral oedema and of the blood-brain barrier status.
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Affiliation(s)
- A Ter Minassian
- Département d'anesthésie-réanimation, CHU d'Angers, 4, rue Larrey, 49033 cedex, Angers, France
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Groom RC. High or low hematocrits during cardiopulmonary bypass for patients undergoing coronary artery bypass graft surgery? An evidence-based approach to the question. Perfusion 2002; 17:99-102. [PMID: 11958311 DOI: 10.1191/0267659102pf548oa] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
We have observed an inverse relationship between a CPB Hct <20% and the need for cardiac support and hospital mortality. These data call for an aggressive and concerted effort to avoid a CPB Hct of <20%. The focus should be directed at women and small men since this subset of patients are most likely to experience low CPB Hct. A comprehensive, multimodality blood-conservation plan that involves the use of erythropoietin, aprotinin, preoperative autologous donation, shed blood reinfusion, and minimal phlebotomy for blood testing was proposed by Rosengart and colleagues based on their experience in caring for 50 Jehovah's Witness patients. Efforts to conserve blood and ensure hemostasis should cover the entire spectrum of care, including preoperative phlebotomy (for blood tests), diagnostic and interventional procedures, and intraoperative and postoperative care. Further work is needed to understand the mechanism for the relationship between low Hct and adverse outcomes. Each open-heart center should consider the Hct question carefully, examining both the published literature and their own results related to CPB Hct and patient outcomes.
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Rebel A, Ulatowski JA, Joung K, Bucci E, Traystman RJ, Koehler RC. Regional cerebral blood flow in cats with cross-linked hemoglobin transfusion during focal cerebral ischemia. Am J Physiol Heart Circ Physiol 2002; 282:H832-41. [PMID: 11834476 DOI: 10.1152/ajpheart.00880.2001] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The beneficial effect of hemodilution on cerebral blood flow (CBF) during focal cerebral ischemia is mitigated by reduced arterial oxygen content (CaO2). In anesthetized cats subjected to permanent middle cerebral artery occlusion, the time course of regional CBF was evaluated after isovolemic exchange transfusion with either albumin or a tetrameric hemoglobin-based oxygen carrier. The transfusion started 30 min after arterial occlusion. We tested the hypothesis that bulk oxygen transport (CBF x CaO2) to ischemic tissue is increased by hemoglobin transfusion at a hematocrit of 18% compared with albumin-transfused cats at a hematocrit of 18% or control cats at a hematocrit of 30% and equivalent arterial pressure. In the nonischemic hemisphere, CBF increased selectively after albumin transfusion, and oxygen transport was similar among groups. In the ischemic cortex, albumin transfusion increased CBF, but oxygen transport was not increased above that of the control group. Hemoglobin transfusion increased both CBF and oxygen transport in the ischemic cortex above values in the control group, but the increase was delayed until 4 h of ischemia. Consequently, acute injury volume measured at 6 h of ischemia was not significantly attenuated. In contrast to the cortex, CBF in the ischemic caudate nucleus was not substantially increased by either albumin or hemoglobin transfusion. Therefore, in a large animal model of permanent focal ischemia in which transfusion starts 30 min after ischemia, tetrameric cross-linked hemoglobin transfusion can augment oxygen transport to the ischemic cortex, but the increase can be delayed and not necessarily provide protection. Moreover, an end-artery region such as the caudate nucleus is less likely to benefit from hemodilution.
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Affiliation(s)
- Annette Rebel
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins Medical Institutions, Baltimore, Maryland 21205, USA
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Abstract
The glycosaminoglycan heparin has been used in the clinic as an anticoagulant for more than 50 years. A fully characterized sequence in native heparin is known to be responsible for this activity. However, heparin is a complex polysaccharide, which has an array of properties that are unrelated to its anticoagulant activity. Recent research has provided us with an increased understanding of the specific structural requirements for the various actions of heparin, indicating that it might be possible to create 'tailor-made' sequences based on the heparin template to isolate specific therapeutic activities. This research should provide the basis for novel drug treatments for a range of diseases, including cancer and various inflammatory diseases.
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Affiliation(s)
- Rebecca Lever
- Sackler Institute of Pulmonary Pharmacology, GKT School of Biomedical Sciences, King's College London, London SE1 9RT, UK.
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Groom RC. High or low hematocrits during cardiopulmonary bypass for patients undergoing coronary artery bypass graft surgery? An evidence-based approach to the question. Perfusion 2001; 16:339-43. [PMID: 11565888 DOI: 10.1177/026765910101600503] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Affiliation(s)
- R C Groom
- Cardiac Surgery, Maine Medical Center, Portland 04102, USA.
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Rössler A, Berrouschot J, Barthel H, Hesse S, Köster J, Schneider D. Potential of rheopheresis for the treatment of acute ischemic stroke when initiated between 6 and 12 hours. THERAPEUTIC APHERESIS : OFFICIAL JOURNAL OF THE INTERNATIONAL SOCIETY FOR APHERESIS AND THE JAPANESE SOCIETY FOR APHERESIS 2000; 4:358-62. [PMID: 11111817 DOI: 10.1046/j.1526-0968.2000.004005358.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Improvement of hemorheology is one of the most important approaches in the treatment of acute ischemic stroke. We investigated the influence of extracorporal rheopheresis (ER) on cerebral blood flow in patients with acute ischemic stroke and evaluated its therapeutic effect. Thirty-three patients (rheopheresis group, 17; control group, 16; mean age 64 +/- 10 years) with acute ischemic stroke were included in our prospective randomized trial. The first treatment was started within 12 h after onset of symptoms, and treatment was repeated 3 times at an interval of 24 h. Hemorheological parameters were measured before and after each session. The cerebral blood flow was analyzed using 99mTc-ECD-SPECT. The functional and neurological outcomes were determined by follow-up investigations after 3 months. The hemorheological parameters were significantly different between the rheopheresis group (18% decrease of plasma viscosity, 55% decrease of red blood cell aggregation) and the control group (no decrease of both parameters). The single photon emission computed tomography (SPECT) analysis showed early reperfusion in 35% of the patients treated with rheopheresis and in 37% of the control group (NS). There were no differences in the neurological outcomes between the 2 groups. Extracorporal rheopheresis is practicable and safe. It rapidly and consistently improved the hemorheological parameters. Although this did not impact on cerebral perfusion or clinical outcome in patients with acute ischemic stroke in this report, we propose that ER deserves to be further evaluated by initiating the first treatment within 6 h post-insult.
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Affiliation(s)
- A Rössler
- Department of Neurology, University of Leipzig, Germany. 3.medizin.uni-leipzig.de
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Mühling J, Dehne MG, Sablotzki A, Hempelmann G. Cerebral blood flow velocity during isovolemic hemodilution and subsequent autologous blood retransfusion. Can J Anaesth 1999; 46:550-7. [PMID: 10391602 DOI: 10.1007/bf03013545] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
PURPOSE To quantify the influence of hematocrit on cerebral blood flow velocity (CBFV) in healthy volunteers undergoing acute isovolemic hemodilution (HD) with hydroxyethyl starch 10% (HES) and subsequent autologous whole blood retransfusion (RT). METHODS In 11 volunteers 20 ml x kg(-1) blood was withdrawn over 30 min and simultaneously replaced with HES 10%. Thirty min later, RT was started at a constant rate over 30 min. Recorded parameters included: CBFV pulsatility-index (PI) and resistance-index (RI) of the middle cerebral artery (MCA). Blood pressure (BP), heart rate (HR), hemoglobin (Hb), hematocrit (Hc) peripheral O2-saturation (SpO2), P(ET)CO2, arterial oxygen content (CaO2) and cerebral arterial O2-transport (C(E)-DO2= CaO2 x Vm-MCA) were monitored. RESULTS An average of 1570 total blood was withdrawn which resulted in a decrease in Hb from 14.5 mg x dl(-1) to 10.3 mg x dl(-1); Hc (and CaO2) decreased from 41.8% (19.8 ml x dl(-1)) to 29.6% (14.2 ml x dl(-1); P < 0.01). Vm-MCA increased from 61.2 cm x sec(-1) to 77.3 cm x sec(-1) (P < 0.01). Following RT, Vm-MCA decreased again, but remained higher than baseline (P < 0.01). PI decreased by 13% following RT (P < 0.05). There were no changes in RI, HR, BP SpO2 and P(ET)CO2. Regression lines could be fitted between Hc and Vm-MCA, Vm-MCA and CaO2, and between Hc and C(E)DO2. CONCLUSIONS Transcranial Doppler changes in blood flow velocities correlated with the simultaneously recorded systemic Hc and CaO2 values. We found a 2% increase in CBFV for each 1% decrease in Hc and CaO2.
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Affiliation(s)
- J Mühling
- Department of Anaesthesiology and Intensive Care Medicine, Justus-Liebig-University, Giessen, Germany
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Roberts M, Hughes G. Recent advances in the acute management of ischaemic stroke. J Accid Emerg Med 1999; 16:7-12. [PMID: 9918278 PMCID: PMC1343244 DOI: 10.1136/emj.16.1.7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- M Roberts
- Department of Emergency Medicine, Wellington Hospital, New Zealand.
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Belayev L, Busto R, Zhao W, Clemens JA, Ginsberg MD. Effect of delayed albumin hemodilution on infarction volume and brain edema after transient middle cerebral artery occlusion in rats. J Neurosurg 1997; 87:595-601. [PMID: 9322848 DOI: 10.3171/jns.1997.87.4.0595] [Citation(s) in RCA: 109] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The authors examined the effect of delayed high-concentration albumin therapy on ischemic injury in a highly reproducible model of middle cerebral artery (MCA) occlusion in rats. Male Sprague-Dawley rats weighing 270 to 320 g were anesthetized with halothane and subjected to 120 minutes of temporary MCA occlusion induced by means of a poly-L-lysine-coated intraluminal nylon suture inserted retrograde via the external carotid artery into the internal carotid artery and MCA. The agent (20% human serum albumin [HSA]) or control solution (sodium chloride 0.9%) was administered intravenously at a dosage of 1% of body weight immediately after suture removal following a 2-hour period of MCA occlusion. The animals' neurological status was evaluated during MCA occlusion (at 60 minutes) and daily for 3 days thereafter. The brains were perfusion-fixed, and infarct volumes and brain edema were determined. The HSA significantly improved the neurological score compared with saline at 24 hours after MCA occlusion. The rats treated with HSA also had significantly reduced total infarct volume (by 34%) and brain edema (by 81%) compared with saline-treated rats. There was a strong correlation between hematocrit level and brain edema (p < 0.01), and between total infarct volume or brain edema and neurological score at 24, 48, and 72 hours postinjury (p < 0.0002). These results strongly support the beneficial effect of delayed albumin therapy in transient focal ischemia and indicate its possible usefulness in treating patients with acute ischemic stroke.
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Affiliation(s)
- L Belayev
- Cerebral Vascular Disease Research Center, Department of Neurology, University of Miami School of Medicine, Florida 33101, USA
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Yanaka K, Camarata PJ, Spellman SR, McCarthy JB, Furcht LT, Low WC. Antagonism of leukocyte adherence by synthetic fibronectin peptide V in a rat model of transient focal cerebral ischemia. Neurosurgery 1997; 40:557-63; discussion 563-4. [PMID: 9055296 DOI: 10.1097/00006123-199703000-00026] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
OBJECTIVE Activated polymorphonuclear leukocytes (PMNs) seem to be directly involved in potentiating ischemic brain injury. Recent work in our laboratory demonstrated that synthetic fibronectin peptides significantly inhibit PMN accumulation in ischemic tissue, reduce the size of infarction, and reduce neurological dysfunction after transient focal cerebral ischemia in rats. The purpose of this study was to examine any dose-related effects (Experiment 1) and the optimal timing of the administration (Experiment 2) of synthetic fibronectin peptide V (FN-C/H-V) to further substantiate the role of the peptide in ameliorating cerebral ischemic damage. METHODS Fifty-six animals were included in the study. We evaluated the efficacy of FN-C/H-V on PMN accumulation in ischemic tissue, infarct size, and neurological outcomes in rats subjected to 1 hour of cerebral ischemia and 48 hours of reperfusion. RESULTS In Experiment 1, the animals receiving FN-C/H-V at a dose of 10 to 15 mg/kg of body weight per injection showed significant reduction of PMN accumulation, reduction of infarct size, and improvement of neurological outcomes at 48 hours after reperfusion compared to untreated animals (P < 0.05). In Experiment 2, the animals receiving FN-C/H-V within 3 hours after reperfusion also showed significantly better results than untreated animals (P < 0.05). Despite the treatment delay, the administration of FN-C/H-V inhibited PMN accumulation after reperfusion but did not reduce the size of infarction when administered 6 hours after reperfusion. CONCLUSION These data suggest that relatively late postischemic administration of FN-C/H-V is effective in brain protection after ischemia/reperfusion.
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Affiliation(s)
- K Yanaka
- Department of Neurosurgery, University of Minnesota Medical School, Minneapolis, USA
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Yanaka K, Camarata PJ, Spellman SR, McCarthy JB, Furcht LT, Low WC. Antagonism of Leukocyte Adherence by Synthetic Fibronectin Peptide V in a Rat Model of Transient Focal Cerebral Ischemia. Neurosurgery 1997. [DOI: 10.1227/00006123-199703000-00026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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Yanaka K, Spellman SR, McCarthy JB, Low WC, Camarata PJ. Reduction of brain injury using heparin to inhibit leukocyte accumulation in a rat model of transient focal cerebral ischemia. II. Dose-response effect and the therapeutic window. J Neurosurg 1996; 85:1108-12. [PMID: 8929503 DOI: 10.3171/jns.1996.85.6.1108] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The administration of massive doses of heparin has been demonstrated to reduce reperfusion injury. The authors have found that heparin's antileukocyte adhesion property may play a more important role than its anticoagulant property in preventing ischemia and reperfusion injury. Although the administration of massive doses of heparin has been demonstrated to reduce brain injury after ischemia and reperfusion, the optimum dosage and timing for heparin administration remain unknown. The purpose of this study was to evaluate the dose-response effect and determine the time during which heparin must be administered to inhibit leukocyte accumulation, reduce infarct size, and improve neurological outcome in rats subjected to 1 hour of cerebral ischemia and 48 hours of reperfusion. Forty-nine animals were included in the study. The animals receiving commercial unfractionated heparin at a total dose of 2.67 to 4 mg/kg showed a significant inhibition of leukocyte accumulation, reduced infarct size, and lessened neurological dysfunction 48 hours after reperfusion (p < 0.05) when compared to untreated animals. The animals receiving unfractionated heparin within 3 hours after reperfusion also showed significantly better results than untreated animals. These data indicate that standard doses of heparin prevent reperfusion injury, and relatively late postischemic administration of heparin also is effective in brain protection. These findings may have therapeutic potential as an adjunct to thrombolytic therapy and possibly for other perfusion deficiencies with leukocyte-endothelial interaction. In view of these encouraging experimental findings, the clinical application of heparin administration after ischemia and reperfusion warrants serious consideration.
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Affiliation(s)
- K Yanaka
- Department of Neurosurgery, University of Minnesota Medical School, Minneapolis, USA
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Yanaka K, Spellman SR, McCarthy JB, Oegema TR, Low WC, Camarata PJ. Reduction of brain injury using heparin to inhibit leukocyte accumulation in a rat model of transient focal cerebral ischemia. I. Protective mechanism. J Neurosurg 1996; 85:1102-7. [PMID: 8929502 DOI: 10.3171/jns.1996.85.6.1102] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Heparin has long been established as an anticoagulant. Although heparin has been demonstrated to reduce brain injury after ischemia and reperfusion, its mechanism of action remains unknown. Recent investigations reveal that it can modulate biological processes such as binding to adhesion receptors on endothelial cells and leukocytes. The authors hypothesized that heparin's protective effect is closely related to its antileukocyte adherence property. They evaluated the efficacy of sulfated polysaccharides (unfractionated heparin, low-molecular-weight heparin, heparan sulfate, chondroitin sulfate C, and dextran sulfate) on leukocyte accumulation, infarction size, and neurological outcome after transient focal cerebral ischemia in rats subjected to 1 hour of ischemia and 48 hours of reperfusion. Forty-nine animals were included in the study. The animals receiving unfractionated heparin or dextran sulfate showed a significant reduction in leukocyte accumulation, infarct size, and neurological dysfunction 48 hours after reperfusion (p < 0.05) when compared to untreated animals. The animals receiving unfractionated heparin also showed significantly better results than the animals receiving an equivalent anticoagulant dose of low-molecular-weight heparin. These data indicate that heparin's antileukocyte property plays a more important role than its anticoagulant ability in neuronal protection. The relative potency of the sulfated polysaccharides tested in leukocyte depletion was closely related to their degree of sulfation. Thus, in addition to demonstrating the potential efficacy of heparin as a therapeutic agent for ischemia and reperfusion injury by the prevention of leukocyte accumulation, the results also serve as a basis for studying important cellular and molecular events that contribute to tissue damage.
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Affiliation(s)
- K Yanaka
- Department of Neurosurgery, University of Minnesota Medical School, Minneapolis, USA
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