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Paulson OB, Schousboe A, Hultborn H. The history of Danish neuroscience. Eur J Neurosci 2023; 58:2893-2960. [PMID: 37477973 DOI: 10.1111/ejn.16062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Revised: 05/04/2023] [Accepted: 05/29/2023] [Indexed: 07/22/2023]
Abstract
The history of Danish neuroscience starts with an account of impressive contributions made at the 17th century. Thomas Bartholin was the first Danish neuroscientist, and his disciple Nicolaus Steno became internationally one of the most prominent neuroscientists in this period. From the start, Danish neuroscience was linked to clinical disciplines. This continued in the 19th and first half of the 20th centuries with new initiatives linking basic neuroscience to clinical neurology and psychiatry in the same scientific environment. Subsequently, from the middle of the 20th century, basic neuroscience was developing rapidly within the preclinical university sector. Clinical neuroscience continued and was even reinforced during this period with important translational research and a close co-operation between basic and clinical neuroscience. To distinguish 'history' from 'present time' is not easy, as many historical events continue in present time. Therefore, we decided to consider 'History' as new major scientific developments in Denmark, which were launched before the end of the 20th century. With this aim, scientists mentioned will have been born, with a few exceptions, no later than the early 1960s. However, we often refer to more recent publications in documenting the developments of initiatives launched before the end of the last century. In addition, several scientists have moved to Denmark after the beginning of the present century, and they certainly are contributing to the present status of Danish neuroscience-but, again, this is not the History of Danish neuroscience.
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Affiliation(s)
- Olaf B Paulson
- Neurobiology Research Unit, Department of Neurology, Rigshospitalet, 9 Blegdamsvej, Copenhagen, Denmark
- Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Arne Schousboe
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Hans Hultborn
- Department of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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Brochu P, Ménard J, Marchand A, Haddad S. Cardiopulmonary values and organ blood flows before and during heat stress: data in nine subjects at rest in the upright position. Can J Physiol Pharmacol 2021; 99:1148-1158. [PMID: 34062083 DOI: 10.1139/cjpp-2021-0044] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Physiological changes associated with thermoregulation can influence the kinetics of chemicals in the human body, such as alveolar ventilation (VA) and redistribution of blood flow to organs. In this study, the influence of heat stress on various physiological parameters was evaluated in nine male volunteers during sessions of exposure to wet blub globe temperatures (WBGT) of 21, 25 and 30°C for four hours. Skin and core temperatures and more than twenty cardiopulmonary parameters were measured. Liver, kidneys, brain, skin and muscles blood flows were also determined based on published measurements. Results show that most subjects (8 out of 9) have been affected by the inhalation of hot and dry air at the WBGT of 30°C. High respiratory rates, superficial tidal volumes and low VA values were notably observed. The skin blood flow has increased by 2.16-fold, whereas the renal blood flow and liver blood flow have decreased by about by 11 and 18% respectively. A complete set of key cardiopulmonary parameters in healthy male adults before and during heat stress was generated for use in PBPK modeling. A toxicokinetic studies are ongoing to evaluate the impact of heat stress on the absorption, biotransformation and excretion rates of volatile xenobiotics.
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Affiliation(s)
- Pierre Brochu
- Université de Montréal, 5622, Environmental and Occupational Health, School of Public Health, Montreal, Quebec, Canada;
| | - Jessie Ménard
- Université de Montréal, 5622, Environmental and Occupational Health, School of Public Health, Montreal, Quebec, Canada.,Centre for Public Health Research (CReSP), Montréal, Quebec, Canada;
| | - Axelle Marchand
- Université de Montréal, 5622, Environmental and Occupational Health, School of Public Health, Montreal, Quebec, Canada.,Centre for Public Health Research (CReSP), Montréal, Quebec, Canada;
| | - Sami Haddad
- Université de Montréal, 5622, Environmental and Occupational Health, School of Public Health, Montreal, Quebec, Canada.,Centre for Public Health Research (CReSP), Montréal, Quebec, Canada;
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YILMAZ DA, YILDIRIM MS, YILDIZ M, OKYAR G. CENTRAL NERVOUS SYSTEM RESPONSE TO CHRONIC KIDNEY DISEASE. KAHRAMANMARAŞ SÜTÇÜ İMAM ÜNIVERSITESI TIP FAKÜLTESI DERGISI 2021. [DOI: 10.17517/ksutfd.917658] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Due to the aging of the human population, the prevalence of chronic diseases such as chronic kidney disease (CKD) is increasing every year. Chronic kidney disease is a general term that refers to heterogeneous disorders that affect kidney structure and function. Decrease in glomerular filtration can be defined as chronic and progressive deterioration in fluid-solute balance, metabolic and endocrine functions of the kidney. CKD often affects the elderly. With the advancement of age, some structural and functional changes occur in the kidneys. Therefore, the number of patients suffering from mild and moderate CKD is expected to increase in the future.CKD leads to the deep metabolic and hemodynamic changes that damage other organs, such as the heart and brain. CNS abnormalities and cognitive deficits progress with the severity of CBS and occurs mostly among hemodialysis patients. It also has great socio-economic effects on individuals. Since symptoms of CKD are not often found in patients, early recognition of risk factors is the main point. For this reason, it is necessary to identify possible protective and preventive treatments to be applied in at-risk groups and to examine these mechanisms for the treatment of the disease. This review provides available information on the relevant mechanisms.
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Lassen A, Stokely E, Vorstrup S, Goldman T, Henriksen JH. Neuro-SPECT: On the development and function of brain emission tomography in the Copenhagen area. Clin Physiol Funct Imaging 2020; 41:10-24. [PMID: 32956526 DOI: 10.1111/cpf.12663] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Revised: 08/17/2020] [Accepted: 09/09/2020] [Indexed: 11/29/2022]
Abstract
This review describes the development of single-photon emission tomography (SPECT) in the Copenhagen area under the leadership of the internationally renown scientist, Niels A. Lassen, and the history leading up to construction of the tomograph. Measurements of global cerebral blood flow (CBF) in the 1940s and 1950s were performed by Kety & Schmidt and Lassen & Munck. Determination of regional cerebral blood flow (rCBF) by intra-arterial injection of 133 Xe and measurement with a 254-multicrystal scintillation detector and a computer system was a major step forward in the study of physiology and pathophysiology of cortical cerebral blood flow. Tomography with radioisotope ligands, including non-invasive administration, was advanced in different centres during the 1970s. An emission tomograph, the Tomomatic 64, was developed as a result of a multidisciplinary Danish and international collaboration. It was the first emission tomograph to provide dynamic data that could produce cross-sectional rCBF images. The present description of the construction and function of the Tomomatic 64 includes comparison with other contemporary and later brain-dedicated SPECT systems. Basic and clinical application of the Tomomatic 64 in Copenhagen resulted in several hundred important scientific publications and improved diagnostics for patients with a variety of neurological disorders. It is concluded that the development of the Tomomatic 64 was a major step forward in the study and examination of rCBF and brain function related to several brain disorders, in addition to vascular diseases.
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Affiliation(s)
- Anders Lassen
- Department of Computer Science (DIKU), Faculty of Science, University of Copenhagen, Copenhagen, Denmark
| | - Ernest Stokely
- Department of Biomedical Engineering, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Sissel Vorstrup
- Department of Neurology, Rigshospitalet, Copenhagen, Denmark
| | - Tomasz Goldman
- Department of Computer Science (DIKU), Faculty of Science, University of Copenhagen, Copenhagen, Denmark
| | - Jens H Henriksen
- Department of Clinical Physiology and Nuclear Medicine, Faculty of Health Science, Center for Functional and Diagnostic Imaging and Research 260, Hvidovre Hospital, University of Copenhagen, Copenhagen, Denmark
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HARPER AM, GLASS HI, GLOVER MM. Measurement of Blood Flow in the Cerebral Cortex of Dogs, by the Clearance of Krypton-85. Scott Med J 2016; 6:12-7. [PMID: 13711675 DOI: 10.1177/003693306100600103] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Mikkelsen MLG, Ambrus R, Miles JE, Poulsen HH, Moltke FB, Eriksen T. Effect of propofol and remifentanil on cerebral perfusion and oxygenation in pigs: a systematic review. Acta Vet Scand 2016; 58:42. [PMID: 27334375 PMCID: PMC4917978 DOI: 10.1186/s13028-016-0223-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2016] [Accepted: 06/13/2016] [Indexed: 12/09/2022] Open
Abstract
The objective of this review is to evaluate the existing literature with regard to the influence of propofol and remifentanil total intravenous anaesthesia (TIVA) on cerebral perfusion and oxygenation in healthy pigs. Anaesthesia has influence on cerebral haemodynamics and it is important not only in human but also in veterinary anaesthesia to preserve optimal regulation of cerebral haemodynamics. Propofol and remifentanil are widely used in neuroanaesthesia and are increasingly used in experimental animal studies. In translational models, the pig has advantages compared to small laboratory animals because of brain anatomy, metabolism, neurophysiological maturation, and cerebral haemodynamics. However, reported effects of propofol and remifentanil on cerebral perfusion and oxygenation in pigs have not been reviewed. An electronic search identified 99 articles in English. Title and abstract screening selected 29 articles for full-text evaluation of which 19 were excluded with reasons. Of the 10 peer-reviewed articles included for review, only three had propofol or remifentanil anaesthesia as the primary study objective and only two directly investigated the effect of anaesthesia on cerebral perfusion and oxygenation (CPO). The evidence evaluated in this systematic review is limited, not focused on propofol and remifentanil and possibly influenced by factors of potential importance for CPO assessment. In one study of healthy pigs, CPO measures were within normal ranges following propofol-remifentanil anaesthesia, and addition of a single remifentanil bolus did not affect regional cerebral oxygen saturation (rSO2). Even though the pool of evidence suggests that propofol and remifentanil alone or in combination have limited effects on CPO in healthy pigs, confirmative evidence is lacking.
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Affiliation(s)
| | - Rikard Ambrus
- Department of Surgical Gastroenterology C, Rigshospitalet, University of Copenhagen, 9 Blegdamsvej, 2100 Copenhagen Ø, Denmark
| | - James Edward Miles
- Department of Veterinary Clinical and Animal Sciences, University of Copenhagen, 16 Dyrlægevej, 1870 Frederiksberg C, Denmark
| | - Helle Harding Poulsen
- Department of Veterinary Clinical and Animal Sciences, University of Copenhagen, 16 Dyrlægevej, 1870 Frederiksberg C, Denmark
| | - Finn Borgbjerg Moltke
- Department of Neuroanaesthesia, Rigshospitalet, University of Copenhagen, 9 Blegdamsvej, 2100 Copenhagen Ø, Denmark
- Department of Anaesthesia, Sealand Hospital, University of Copenhagen, 1 Lykkebækvej, 4600 Køge, Denmark
| | - Thomas Eriksen
- Department of Veterinary Clinical and Animal Sciences, University of Copenhagen, 16 Dyrlægevej, 1870 Frederiksberg C, Denmark
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Kampp M, Lundgren O. Blood Flow and Flow Distribution in the Small Intestine of the Cat as Analysed by the Kr85Wash-Out Technique. ACTA ACUST UNITED AC 2014. [DOI: 10.1111/j.1365-201x.1968.tb10835.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Henriksen JH, Jensen GB, Larsson HBW. A century of indicator dilution technique. Clin Physiol Funct Imaging 2013; 34:1-9. [DOI: 10.1111/cpf.12068] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2013] [Accepted: 06/28/2013] [Indexed: 11/30/2022]
Affiliation(s)
- Jens H. Henriksen
- Department of Clinical Physiology and Nuclear Medicine 239; Center of Functional and Diagnostic Imaging and Research; Hvidovre Hospital; Faculty of Health Sciences; University of Copenhagen; Hvidovre Denmark
| | - Gorm B. Jensen
- Department of Cardiology; Hvidovre Hospital; Faculty of Health Sciences; University of Copenhagen; Hvidovre Denmark
| | - Henrik B. W. Larsson
- Functional Imaging Unit; Diagnostic Department; Glostrup Hospital; Faculty of Health Sciences; University of Copenhagen; Glostrup Denmark
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Seifert T, Secher NH. Sympathetic influence on cerebral blood flow and metabolism during exercise in humans. Prog Neurobiol 2011; 95:406-26. [PMID: 21963551 DOI: 10.1016/j.pneurobio.2011.09.008] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2011] [Revised: 09/13/2011] [Accepted: 09/19/2011] [Indexed: 11/26/2022]
Abstract
This review focuses on the possibility that autonomic activity influences cerebral blood flow (CBF) and metabolism during exercise in humans. Apart from cerebral autoregulation, the arterial carbon dioxide tension, and neuronal activation, it may be that the autonomic nervous system influences CBF as evidenced by pharmacological manipulation of adrenergic and cholinergic receptors. Cholinergic blockade by glycopyrrolate blocks the exercise-induced increase in the transcranial Doppler determined mean flow velocity (MCA Vmean). Conversely, alpha-adrenergic activation increases that expression of cerebral perfusion and reduces the near-infrared determined cerebral oxygenation at rest, but not during exercise associated with an increased cerebral metabolic rate for oxygen (CMRO(2)), suggesting competition between CMRO(2) and sympathetic control of CBF. CMRO(2) does not change during even intense handgrip, but increases during cycling exercise. The increase in CMRO(2) is unaffected by beta-adrenergic blockade even though CBF is reduced suggesting that cerebral oxygenation becomes critical and a limited cerebral mitochondrial oxygen tension may induce fatigue. Also, sympathetic activity may drive cerebral non-oxidative carbohydrate uptake during exercise. Adrenaline appears to accelerate cerebral glycolysis through a beta2-adrenergic receptor mechanism since noradrenaline is without such an effect. In addition, the exercise-induced cerebral non-oxidative carbohydrate uptake is blocked by combined beta 1/2-adrenergic blockade, but not by beta1-adrenergic blockade. Furthermore, endurance training appears to lower the cerebral non-oxidative carbohydrate uptake and preserve cerebral oxygenation during submaximal exercise. This is possibly related to an attenuated catecholamine response. Finally, exercise promotes brain health as evidenced by increased release of brain-derived neurotrophic factor (BDNF) from the brain.
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Affiliation(s)
- Thomas Seifert
- Department of Anaesthesia and The Copenhagen Muscle Research Centre, Rigshospitalet 2041, University of Copenhagen, Blegdamsvej 9, DK-2100 Copenhagen Ø, Denmark.
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Lassen NA, Henriksen O, Sejrsen P. Indicator Methods for Measurement of Organ and Tissue Blood Flow. Compr Physiol 2011. [DOI: 10.1002/cphy.cp020302] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Abstract
In the late 1970s, high cerebral blood flow was perceived as a cause of intracranial hemorrhage in the preterm infant. Intracranial hemorrhage was diagnosed by computed tomography and ultrasound found to be frequent not only in babies who died. Hemorrhage was soon linked to cerebral palsy in survivors. The analogy was hypertensive hemorrhagic stroke in the adult. Cerebral hemorrhage was perceived as the major (preventable) cause of brain injury in the preterm baby. An immature cerebral autoregulation or a vulnerability of the autoregulation exposed by preceding hypoxia or ischemia therefore became a focus of neonatal brain research in the 1980s. Over the years the focus has changed, first to the pathogenesis of hypoxic-ischemic brain injury, then to the effects of pCO(2), and now 30 years later to a more comprehensive, less clearly hypothesis-driven exploration of the multitude of factors involved in cerebral blood flow and oxygenation. Meanwhile, some basic questions regarding autoregulation remain unanswered, and some concepts from the 1970s still direct clinical practice.
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Affiliation(s)
- Gorm Greisen
- Department of Neonatology, Rigshospitalet, Copenhagen, Denmark.
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Influence of ventilation mode on neonatal cerebral blood flow and volume. Early Hum Dev 2009; 85:415-9. [PMID: 19217223 DOI: 10.1016/j.earlhumdev.2009.01.008] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/05/2008] [Revised: 01/17/2009] [Accepted: 01/20/2009] [Indexed: 11/23/2022]
Abstract
BACKGROUND Cerebral hemodynamics is supposed to be influenced by the different ventilation approach. Ventilation support can be classified as non-invasive (N-CPAP) or invasive (SIMV and HFV), the last known to induce endotrauma. Our aim was the non-invasive NIRS assessment of neonatal absolute cerebral blood flow (CBF) and relative cerebral blood volume changes (DeltaCBV) during synchronized intermittent ventilation (SIMV), or high frequency ventilation (HFV) and nasal continuous positive airways pressure (CPAP). METHODS An observational study in a tertiary referral NICU. CBF and DeltaCBV changes were assessed in 41 preterm newborn infants with respiratory distress syndrome treated using mechanical ventilation or the CPAP device. RESULTS Basal chromophore traces enabled DeltaCBV (mL/100 g) changes to be calculated. CBF was calculated in mL/100 g/min from the saturation rise integral and rate of rise [O(2)Hb-HHb]. Median DeltaCBV was 0.07 (range 0.01-0.13) in SIMV group, 0.07 (0.01-0.19) in HFV group and 0.13 (0.10-1.28) in CPAP group. Median CBF was 14.44 (2.70-32.10), 9.20 (2.94-19.58) and 31.69 (13.59-34.93) respectively. A multiple regression model showed a significant correlation between DeltaCBV or CBF and ventilation approach. CONCLUSION In the light of our results, we might speculate that, assuming that hemodynamic autoregulation is safe and arterial blood pressure is preserved, ventilation per se influences brain circulation.
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Abstract
We reviewed the literature on human cerebral circulation and oxygen metabolism, as measured by positron emission tomography (PET), with respect to normal values and of regulation of cerebral circulation. A multicenter study in Japan showed that between-center variations in cerebral blood flow (CBF), cerebral blood volume (CBV), cerebral oxygen extraction fraction (OEF) and cerebral metabolic rate of oxygen (CMRO2) values were not considerably larger than the corresponding within-center variations. Overall mean +/- SD values in cerebral cortical regions of normal human subjects were as follows: CBF = 44.4 +/- 6.5 ml/100 ml/min; CBV = 3.8 +/- 0.7 ml/100 ml; OEF = 0.44 +/- 0.06; CMRO2 = 3.3 +/- 0.5 ml/100 ml/min (11 PET centers, 70 subjects). Intrinsic regulation of cerebral circulation involves several factors. Autoregulation maintains CBF in response to changes in cerebral perfusion pressure; chemical factors such as PaCO2 affect cerebral vascular tone and alter CBF; changes in neural activity cause changes in cerebral energy metabolism and CBF; neurogenic control of CBF occurs by sympathetic innervation. Regional differences in vascular response to changes in PaCO2 have been reported, indicating regional differences in cerebral vascular tone. Relations between CBF and CBV during changes in PaCO2 and during changes in neural activity were in good agreement with Poiseuille's law. The mechanisms of vascular response to neural activation and deactivation were independent on those of responses to PaCO2 changes. CBV in a brain region is the sum of three components: arterial, capillary and venous blood volumes. It has been reported that the arterial blood volume fraction is approximately 30% in humans and that changes in human CBV during changes in PaCO2 are caused by changes in arterial blood volume without changes in venous blood volume. These findings should be considered in future studies of the pathophysiology of cerebrovascular diseases.
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Affiliation(s)
- Hiroshi Ito
- Department of Nuclear Medicine and Radiology, Division of Brain Sciences, Institute of Development, Aging and Cancer, Tohoku University, 4-1 Seiryo-machi, Aoba-ku, Sendai 980-8575, Japan.
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Taudorf S, Berg RMG, Bailey DM, Møller K. Cerebral blood flow and oxygen metabolism measured with the Kety-Schmidt method using nitrous oxide. Acta Anaesthesiol Scand 2009; 53:159-67. [PMID: 19076112 DOI: 10.1111/j.1399-6576.2008.01788.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
BACKGROUND The Kety-Schmidt method is the reference method for measuring global cerebral blood flow (CBF), cerebral metabolic rates (CMR) and flux, especially where scanners are unavailable or impractical. Our primary objective was to assess the repeatability of the Kety-Schmidt method in a variety of different approaches using inhaled nitrous oxide (N2O) as the tracer, combined with photoacoustic spectrometry. A secondary objective was to assess the impact of this tracer on the systemic vascular concentration of nitrite (NO2(-)). METHODS Twenty-nine healthy male volunteers underwent 61 CBF measurements by breathing a normoxic gas mixture containing 5% N2O until tension equilibrium. Paired blood samples were collected from an arterial and a jugular bulb catheter in the saturation or desaturation phase, by continuous or the discontinuous sampling. N2O concentration was measured with photoacoustic spectrometry after equilibration of blood samples with air. CBF was calculated by the Kety-Schmidt equation. CMR of oxygen (CMRO2) was determined by the Fick principle. NO2(-) in plasma and red blood cells (RBC) was measured by ozone-based chemiluminescence. RESULTS The most robust approach for CBF measurement was achieved by discontinuous sampling in the desaturation phase [CBF, 64 (95% confidence interval, 59-71 ml)] 100 g/min; CMRO2 1.8 (1.7-2.0) micromol/g/min). The tracer did not influence plasma or RBC NO2(-) (P>0.05 vs. baseline). CONCLUSION These findings confirm the reliability and robustness of the Kety-Schmidt method using inhaled N2O for the measurement of global CBF and CMR. At the low tracer concentration used, altered NO metabolism is unlikely to have affected cerebral haemodynamic function.
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Affiliation(s)
- S Taudorf
- Department of Infectious Diseases, Centre of Inflammation and Metabolism, Rigshospitalet, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark
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Klee A. THE RELATIONSHIP BETWEEN CLINICAL EVALUATION OF MENTAL DETERIORATION, PSYCHOLOGICAL TEST RESULTS, AND THE CEREBRAL METABOLIC RATE OF OXYGEN. Acta Neurol Scand 2009; 40:337-45. [PMID: 14215764 DOI: 10.1111/j.1600-0404.1964.tb02757.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Wollman H, Alexander SC, Cohen PJ, Stephen GW, Zeiger LS. Two-compartment analysis of the blood flow in the human brain. ACTA NEUROLOGICA SCANDINAVICA. SUPPLEMENTUM 2009; 14:79-82. [PMID: 5214108 DOI: 10.1111/j.1600-0404.1965.tb01959.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
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Literature. Acta Neurol Scand 2009. [DOI: 10.1111/j.1600-0404.1974.tb02337.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Høedt-Rasmussen K. REGIONAL CEREBRAL BLOOD FLOW IN MAN MEASURED EXTERNALLY FOLLOWING INTRA-ARTERIAL ADMINISTRATION OF 85Kr OR 133Xe DISSOLVED IN SALINE. Acta Neurol Scand 2009. [DOI: 10.1111/j.1600-0404.1965.tb01956.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Géraud J, Bès A, Delpla M, Marc-Vergnes JP, Guiraud B. Measurement of regional cerebral blood flow by intra-carotid injection of xenon 133 in cerebral vascular accidents. ACTA NEUROLOGICA SCANDINAVICA. SUPPLEMENTUM 2009; 14:169-75. [PMID: 5214093 DOI: 10.1111/j.1600-0404.1965.tb01980.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
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Zaramella P, Freato F, Grazzina N, Saraceni E, Vianello A, Chiandetti L. Does helmet CPAP reduce cerebral blood flow and volume by comparison with Infant Flow driver CPAP in preterm neonates? Intensive Care Med 2006; 32:1613-9. [PMID: 16896862 DOI: 10.1007/s00134-006-0289-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2005] [Accepted: 06/22/2006] [Indexed: 10/24/2022]
Abstract
OBJECTIVE We compared neonatal helmet continuous positive airway pressure (CPAP) and the conventional nasal Infant Flow driver (IFD) CPAP in the noninvasive assessment of absolute cerebral blood flow (CBF) and relative cerebral blood volume changes (DeltaCBV) by near-infrared spectroscopy. DESIGN AND SETTING A randomized crossover study in a tertiary referral NICU. PATIENTS AND INTERVENTIONS Assessment of CBF and DeltaCBV in 17 very low birth weight infants with respiratory distress (median age 5 days) treated with two CPAP devices at a continuous distending pressure of 4 mbar. MEASUREMENTS AND RESULTS Neonates were studied for two consecutive 60-min periods with helmet CPAP and with IFD CPAP. Basal chromophore traces enabled DeltaCBV changes to be calculated. CBF was calculated in milliliters per 100 grams per minute from the saturation rise integral and rate of rise O(2)Hb-HHb. Median (range) CBF with helmet CPAP was 27.37 (9.47-48.20) vs. IFD CBF 34.74 (13.59-60.10)(p=0.049) and DeltaCBV 0.15 (0.09-0.28) with IFD and 0.13 (0.07-0.27) with helmet CPAP (NS). Using helmet and IFD CPAP, the neonates showed no difference in mean physiological parameters (transcutaneous carbon dioxide and oxygen tension, pulse oximetry saturation, heart rate, breathing rate, mean arterial blood pressure, desaturation rate, axillary temperature). CONCLUSION Assessing CBF and DeltaCBV measured by near-infrared spectroscopy with two CPAP devices revealed no differences in relative blood volume, but CBF was lower with helmet CPAP. Greater active vasoconstriction and/or passive capillary and/or venous vessel compression seem the most likely reason, due to a positive pressure around the head, neck, and shoulders by comparison with the airway pressure.
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Affiliation(s)
- Patrizia Zaramella
- Department of Pediatrics, University of Padova, Neonatal Intensive Care Unit, Padua, Italy.
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Kolbitsch C, Lorenz IH, Hörmann C, Hinteregger M, Löckinger A, Moser PL, Kremser C, Schocke M, Felber S, Pfeiffer KP, Benzer A. The influence of hyperoxia on regional cerebral blood flow (rCBF), regional cerebral blood volume (rCBV) and cerebral blood flow velocity in the middle cerebral artery (CBFVMCA) in human volunteers. Magn Reson Imaging 2002; 20:535-41. [PMID: 12413599 DOI: 10.1016/s0730-725x(02)00534-9] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Conflicting results reported on the effects of hyperoxia on cerebral hemodynamics have been attributed mainly to methodical and species differences. In the present study contrast-enhanced magnetic resonance imaging (MRI) perfusion measurement was used to analyze the influence of hyperoxia (fraction of inspired oxygen (FiO2) = 1.0) on regional cerebral blood flow (rCBF) and regional cerebral blood volume (rCBV) in awake, normoventilating volunteers (n = 19). Furthermore, the experiment was repeated in 20 volunteers for transcranial Doppler sonography (TCD) measurement of cerebral blood flow velocity in the middle cerebral artery (CBFV(MCA)). When compared to normoxia (FiO2 = 0.21), hyperoxia heterogeneously influenced rCBV (4.95 +/- 0.02 to 12.87 +/- 0.08 mL/100g (FiO2 = 0.21) vs. 4.50 +/- 0.02 to 13.09 +/- 0.09 mL/100g (FiO2 = 1.0). In contrast, hyperoxia diminished rCBF in all regions (68.08 +/- 0.38 to 199.58 +/- 1.58 mL/100g/min (FiO2 = 0.21) vs. 58.63 +/- 0.32 to 175.16 +/- 1.51 mL/100g/min (FiO2 = 1.0)) except in parietal and left frontal gray matter. CBFV(MCA) remained unchanged regardless of the inspired oxygen fraction (62 +/- 9 cm/s (FiO2 = 0.21) vs. 64 +/- 8 cm/s (FiO2 = 1.0)). Finding CBFV(MCA) unchanged during hyperoxia is consistent with the present study's unchanged rCBF in parietal and left frontal gray matter. In these fronto-parietal regions predominantly fed by the middle cerebral artery, the vasoconstrictor effect of oxygen was probably counteracted by increased perfusion of foci of neuronal activity controlling general behavior and arousal.
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Affiliation(s)
- Christian Kolbitsch
- Department of Anaesthesia and Intensive Care Medicine, University of Innsbruck, Innsbruck, Austria.
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GLASS HI, HARPER AM. The Measurement of the Partition Coefficient of Krypton between Brain Cortex and Blood by a Double Isotope Method. Phys Med Biol 2002; 7:335-9. [PMID: 13948377 DOI: 10.1088/0031-9155/7/3/306] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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24
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GLASS HI, HARPER AM, GLOVER MM. The Measurement of Local Cortical Blood Flow in the Brain by the Analysis of the Clearance Curve of Krypton-85. Phys Med Biol 2002; 6:65-71. [PMID: 13705944 DOI: 10.1088/0031-9155/6/1/305] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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25
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Costa DC. For: Can ROI methodology/normalised tissue activities be used instead of absolute blood flow measurements in the brain? Eur J Nucl Med Mol Imaging 2002; 29:948-53. [PMID: 12212547 DOI: 10.1007/s00259-002-0837-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Durval C Costa
- Institute of Nuclear Medicine, University College London, Middlesex Hospital site, United Kingdom.
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26
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Sase S, Honda M, Kushida T, Seiki Y, Machida K, Shibata I. Quantitative cerebral blood flow calculation method using white matter lambda in xenon CT. J Comput Assist Tomogr 2002; 26:471-8. [PMID: 12016383 DOI: 10.1097/00004728-200205000-00028] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The objective of this work is to propose a quantitative cerebral blood flow (CBF) calculation method for xenon CT (Xe-CT) by logically estimating the time course change rate (rate constant) of the arterial xenon concentration from that of end-tidal xenon concentration. A single factor, gamma (gamma), which is considered to reflect the diffusing capacity of the lung for xenon, was introduced to correlate the end-tidal rate constant (Kend-tidal) with the arterial rate constant (Karterial). When an appropriate value is given to gamma, it is possible to calculate the arterial rate constant (calculated Karterial) from Kend-tidal. A procedure was developed to determine the gamma value utilizing the characteristics of white matter lambda (lambda). This procedure was applied to three healthy volunteers. The gamma gammaalues for the three subjects were consistent with those directly calculated from end-tidal and arterial (abdominal aorta) xenon data. Hemispheric CBF values with use of calculated Karterial (47.3 +/- 10.3 ml/100 g/min) were close to the reported normative values. We conclude this method could make current Xe-CT examinations substantially reliable and quantitative in measuring CBF.
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Affiliation(s)
- Shigeru Sase
- Anzai Medical Co., Ltd., Nishi-Shinagawa, Shinagawa-ku, Tokyo, Japan.
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27
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Lottes G, Schober O. Zur Geschichte der Nuklearmedizin – eine chronologische Darstellung der Ursprünge aus Naturwissenschaft, Technik und Medizin. Z Med Phys 2000. [DOI: 10.1016/s0939-3889(15)70285-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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28
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Abstract
The first step to make in improving neurologic outcome is to recognize and accept neurologic injury occurs in all patient groups undergoing CPB. Fortunately, that stage has now been passed. Accurate detection and documentation of the incidence of brain injury is the next progression. At the same time, the cause of the injury needs to be established. Since the introduction of CPB, numerous improvements and refinements have been achieved, making it the acceptable, everyday clinical tool that has enabled the development of cardiac surgery. Despite these improvements, CPB-related morbidity persists. The advent of new technologic advances drives the quest for new techniques. New protective strategies for many end organs, including the heart, kidney, and brain, are evolving. No organ system should be viewed in isolation; otherwise, organ-specific protective strategies may arise in conflict. A strategy that confers absolute myocardial protection would be ideal, but at what cost to the protection of the kidneys, intestines, and brain? A neuroprotective strategy would ideally eliminate brain injury and be beneficial for all organs. The only way to continue to make progress is by the scientific evaluation of new techniques. The use of appropriate monitoring and outcome measures is fundamental to this process.
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Affiliation(s)
- D A Stump
- Department of Anesthesiology, Wake Forest University School of Medicine, Winston-Salem, NC 27157-1009, USA
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29
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Abstract
Dynamic nuclear medicine studies can generate large quantities of data, and their analysis consists essentially of a reduction of these data to a small number of relevant parameters which will assist in clinical decision making. This review examines some of the mathematical techniques that have been used in the process of data reduction and attempts to explain the principles behind their application. It particularly identifies the techniques that have stood the test of time and demonstrated their usefulness, many of which are now available as standard tools on nuclear medicine processing computers. These include curve processing tools such as smoothing, fitting and factor analysis, as well as tools based on empirical models, such as the Patlak/Rutland plot and deconvolution. Compartmental models and vascular models are also examined and the review finishes with a summary of some functional images and condensed images. It is concluded that an appreciation of the principles and limitations of these mathematical tools is valuable for their correct usage and interpretation of the results produced.
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Affiliation(s)
- R S Lawson
- Department of Medical Physics, Manchester Royal Infirmary, UK.
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30
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ROCHESTER DF, DURAND J, PARKER JO, FRITTS HW, HARVEY RM. Estimation of right ventricular output in man using radioactive krypton (Kr85). J Clin Invest 1998; 40:643-8. [PMID: 13742474 PMCID: PMC290769 DOI: 10.1172/jci104296] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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31
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LASSEN NA, FEINBERG I, LANE MH. Bilateral studies of cerebral oxygen uptake in young and aged normal subjects and in patients with organic dementia. J Clin Invest 1998; 39:491-500. [PMID: 14414378 PMCID: PMC293329 DOI: 10.1172/jci104063] [Citation(s) in RCA: 139] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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32
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LEWIS BM, SOKOLOFF L, WECHSLER RL, WENTZ WB, KETY SS. A method for the continuous measurement of cerebral blood flow in man by means of radioactive krvoton (Kr79). J Clin Invest 1998; 39:707-16. [PMID: 14416495 PMCID: PMC293362 DOI: 10.1172/jci104087] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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33
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FRITTS HW, HARDEWIG A, ROCHESTER DF, DURAND J, COURNAND A. Estimation of pulmonary arteriovenous shunt-flow using intravenous injections of T-1824 dye and Kr85. J Clin Invest 1998; 39:1841-50. [PMID: 13702145 PMCID: PMC441909 DOI: 10.1172/jci104208] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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34
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de Vries JW, Bakker PF, Visser GH, Diephuis JC, van Huffelen AC. Changes in cerebral oxygen uptake and cerebral electrical activity during defibrillation threshold testing. Anesth Analg 1998; 87:16-20. [PMID: 9661538 DOI: 10.1097/00000539-199807000-00005] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
UNLABELLED During cardioverter-defibrillator implantation, repeated episodes of ventricular fibrillation (VF) are induced. Insufficient recovery of oxygen metabolism may cause neurological sequelae. In this prospective clinical study, we monitored the electroencephalogram (EEG), middle cerebral artery blood flow velocity (Vmca), and jugular bulb oxygen saturation and estimated cerebral oxygen uptake. Results were analyzed for tests requiring a single shock (Group 1) and tests requiring multiple shocks for defibrillation (Group 2). Immediately after the induction of VF, the mean arterial blood pressure (MAP) decreased to < 30 mm Hg, and the Vmca decreased to 0 cm/s. The EEG showed ischemic changes consisting of a decrease of fast, and an increase of slow, activity, progressively declining to isoelectricity within 11 +/- 2 s. After defibrillation, the MAP recovered rapidly regardless of the arrest duration (3 +/- 2 s). The EEG recovered within 17 +/- 9 and 22 +/- 12 s, respectively, for Groups 1 and 2 (P < 0.05) and did not reveal ischemic changes until induction of a subsequent arrest. In Group 1, the cerebral oxygen uptake increased to 191% +/- 31% of baseline values and returned to baseline in 16 +/- 7 s, whereas in Group 2, it increased to 229% +/- 38% (P < 0.05), followed by a significant decrease to less than baseline (85% +/- 18%; P < 0.005), and returned to baseline simultaneously with the Vmca. We conclude that, although restoration to normal of the EEG and cerebral oxygen uptake coincide in short arrests, EEG recovery underestimates metabolic recovery after tests requiring multiple shocks. IMPLICATIONS Short test intervals have been mentioned as a cause of neurological sequelae after cardioverter-defibrillator implantation. This study demonstrates that although all systemic hemodynamic variables and the electrocardiogram may have returned to normal, cerebral oxygen uptake may still be depressed for a considerable time, especially after tests requiring two or more shocks.
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Affiliation(s)
- J W de Vries
- Institute for Anesthesia, Ac. Hospital Utrecht, The Netherlands
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35
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de Vries JW, Bakker PFA, Visser GH, Diephuis JC, van Huffelen AC. Changes in Cerebral Oxygen Uptake and Cerebral Electrical Activity During Defibrillation Threshold Testing. Anesth Analg 1998. [DOI: 10.1213/00000539-199807000-00005] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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36
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Abstract
The rate of energy loss of helium and nitrogen ions passing through thin aluminium, nickel, silver and gold foils has been measured. Results are presented for helium ions in the energy interval of 0.4 to 1.0 MeV and for nitrogen ions up to T8 MeV. The relative accuracy of the results is about 1 % and the absolute accuracy better than 5 %. Relative mass stopping powers for helium ions at 3.72 and 4.33 MeV are also quoted. Results are compared with earlier work, where available, and agreement is found to be within the experimental errors.
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37
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Kanno I, Shimosegawa E, Fujita H, Hatazawa J. Uncoupling of absolute CBF to neural activity. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 1997; 413:209-14. [PMID: 9238502 DOI: 10.1007/978-1-4899-0056-2_23] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Affiliation(s)
- I Kanno
- Department of Radiology and Nuclear Medicine, Akita Research Institute of Brain and Blood Vessels, Japan
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38
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ROSS RS, UEDA K, LICHTLEN PR, REES JR. MEASUREMENT OF MYOCARDIAL BLOOD FLOW IN ANIMALS AND MAN BY SELECTIVE INJECTION OF RADIOACTIVE INERT GAS INTO THE CORONARY ARTERIES. Circ Res 1996; 15:28-41. [PMID: 14196204 DOI: 10.1161/01.res.15.1.28] [Citation(s) in RCA: 217] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Key Words] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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39
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Abstract
When a platinized platinum electrode is polarized at the potential of the standard calomel electrode, the current generated is proportional to the concentration of dissolved hydrogen gas. The effects of physiological variations in oxygen tension, pH, temperature, and ascorbic acid concentration were found to be negligible. Although absolute calibration in vivo is not possible, the rate of tissue hydrogen saturation or desaturation can be measured by needle-shaped electrodes inserted into the tissue. Arterial and venous concentration can be measured with catheter electrodes. Solubility of hydrogen gas in kidney slices was found to be the same as in blood. With the assumption that tissue is in instantaneous diffusion equilibrium with local venous blood with respect to hydrogen, the local blood flow per volume of tissue can be calculated according to the Fick principle from the rate of tissue desaturation when arterial concentration is lowered to zero.
The method was tested on dogs in myocardium, kidney, and skeletal muscle. Hydrogen was administered by respiration or by intra-arterial infusion of hydrogen-saturated saline, giving an arterial concentration of 3% to 5% saturation. Tissue desaturation curves were recorded simultaneously from two to three tissue electrodes. Good agreement with flow measured simultaneously with other methods was obtained in myocardium and renal cortex, while the data on skeletal muscle do not permit any definite conclusion. The main virtue of this method lies in the fact that repeated measurements of local blood flow can be obtained without access to arterial or local venous blood. Reliable measurements of regional blood flow were also obtained from continuously recorded venous desaturation curves, which also provide information on the distribution of blood flow.
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40
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LASSEN NA, KLEE A. CEREBRAL BLOOD FLOW DETERMINED BY SATURATION AND DESATURATION WITH KRYPTON-85: AN EVALUATION OF THE VALIDITY OF THE INERT GAS; METHOD OF KETY AND SCHMIDT. Circ Res 1996; 16:26-32. [PMID: 14252153 DOI: 10.1161/01.res.16.1.26] [Citation(s) in RCA: 51] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Key Words] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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41
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Cerebral Glucose/Energy Metabolism: Valid Techniques in Humans and Animals. ACTA ACUST UNITED AC 1996. [DOI: 10.1016/s1043-9471(96)80101-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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42
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Hatazawa J, Fujita H, Kanno I, Satoh T, Iida H, Miura S, Murakami M, Okudera T, Inugami A, Ogawa T. Regional cerebral blood flow, blood volume, oxygen extraction fraction, and oxygen utilization rate in normal volunteers measured by the autoradiographic technique and the single breath inhalation method. Ann Nucl Med 1995; 9:15-21. [PMID: 7779525 DOI: 10.1007/bf03165003] [Citation(s) in RCA: 91] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
By means of a high resolution PET scanner, the regional cerebral blood flow (rCBF), cerebral blood volume (rCBV), oxygen extraction fraction (rOEF), and metabolic rate of oxygen (rCMRO2) for major cerebral gyri and deep brain structures were studied in eleven normal volunteers during an eye-covered and ear-unplugged resting condition. Regional CBF was measured by the autoradiographic method after intravenous administration of H2(15)O. Regional OEF and rCMRO2 were measured by the single inhalation of 15O2. With MR T1-weighted images as an anatomical reference, thirteen major cerebral gyri, caudate nucleus, lentiform nucleus, thalamus, midbrain, pons, cerebellum and vermis were defined on the CMRO2 images. Values were read by using circular regions of interest 16 mm in diameter. The posterior part of the cingulate gyri had the highest rCBF and rCMRO2 values among brain structures, followed by the lentiform nucleus, the cerebellum, the caudate nucleus, and the thalamus. Parahippocampal gyri had the lowest rCBF and rCMRO2 values among the cortical gyri. Regional OEF for the pontine nuclei (0.34 +/- 0.04), the midbrain (0.35 +/- 0.05), the parahippocampal gyri (0.35 +/- 0.04 for the right and 0.37 +/- 0.05 for the left), and the thalami (0.37 +/- 0.05 for the right and 0.36 +/- 0.04 for the left) were significantly lower than the mean OEF for the cerebral cortices (0.42 +/- 0.04) (p < 0.05 or less). The global CBF and CMRO2 were consistent with those obtained by the Kety-Schmidt method.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- J Hatazawa
- Department of Radiology and Nuclear Medicine, Akita Research Institute of Brain and Blood Vessels, Japan
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43
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Abstract
Since the first description of the movement of blood around the body by William Harvey, the accurate measurement of blood velocity has provided a major challenge for medical science. This review looks at the contribution made by techniques using radioactive tracers. Initially consideration is given to the fundamental problem of how to measure the amount of radiotracer in an organ with sufficient accuracy, using both single-photon and positron-emitting tracers. The various models used to link tracer behaviour with blood flow are then discussed and the article closes with a detailed review of the clinical applications of blood flow measurements.
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Affiliation(s)
- P F Sharp
- Department of Biomedical Physics and Bioengineering, University of Aberdeen/Aberdeen Royal Hospitals NHS Trust, Foresterhill, UK
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44
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Gloor P. Berger lecture. Is Berger's dream coming true? ELECTROENCEPHALOGRAPHY AND CLINICAL NEUROPHYSIOLOGY 1994; 90:253-66. [PMID: 7512906 DOI: 10.1016/0013-4694(94)90143-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
In the last quarter of our century technologies have been developed that permit us to measure and localize with previously unknown precision physiological concomitants of mental activities. Human in vivo cerebral psychophysiology has come of age, decades after the discovery of EEG. In part this has come about through the development of PET and most recently dynamic MRI. However, it is hardly known today that the concepts which underlie these modern methods of studying the physiological correlates of human mental activity were the focus of Berger's early research at the onset of his scientific career at the turn of the century. Indeed at that time he attempted to study human mental function through measuring cerebral blood flow by means of plethysmography applied to patients who had pulsating skull defects. He also measured intracerebral temperature changes during neurosurgical procedures in awake, locally anesthetized, patients in a quest of identifying metabolic concomitants of mental activity. He was thus well ahead of his time, but was forced to give up these methods because they were not commensurate to the task. Only at age 50 he turned to electrophysiology and discovered the EEG. At last he was able to identify some electrophysiological facets of human psychophysiology related to attention, sleep, wakefulness and coma. This essay will illustrate some examples of PET, functional MRI, computerized EEG and cerebral electrical stimulation studies that show that Berger's conceptual approaches to human psychophysiology, even though he could not effectively apply them himself, were correct and have become powerful tools of modern neuroscience.
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Affiliation(s)
- P Gloor
- Montreal Neurological Institute, McGill University, QC, Canada
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46
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Sharples PM, Stuart AG, Aynsley-Green A, Heaviside D, Pay DA, McGann A, Crawford PJ, Harpin R, Eyre JA. A practical method of serial bedside measurement of cerebral blood flow and metabolism during neurointensive care. Arch Dis Child 1991; 66:1326-32. [PMID: 1755648 PMCID: PMC1793280 DOI: 10.1136/adc.66.11.1326] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Acute encephalopathy is a major cause of death and neurological handicap in children. The principle aims of treatment are to provide adequate cerebral blood flow for the brain's metabolic needs and to prevent intracranial pressure rising above the level at which brain herniation occurs. Rational management requires an understanding of the pathophysiological changes in cerebral blood flow and metabolism which occur. The paucity of data on this subject reflects the perceived difficulty of measuring cerebral blood flow and cerebral metabolism in children. A modification of the Kety Schmidt technique of measuring cerebral blood flow and cerebral metabolism is described. This modification makes it possible to perform serial bedside measurements in children receiving intensive care. This method was used to perform 348 measurements in 58 children. The method was reproducible and no significant complications were encountered. The results indicated that appreciable changes in cerebral blood flow and metabolism could occur in individual patients over time, emphasising the importance of serial measurements. This technique may provide a practical means of monitoring cerebral blood flow and metabolism in very sick children receiving neurointensive care and evaluating the efficacy of treatment.
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Affiliation(s)
- P M Sharples
- University of Newcastle upon Tyne, Department of Child Health, Paediatric Neurology Research Unit
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47
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Murkin JM, Lee DH. Noninvasive measurement of cerebral blood flow: techniques and limitations. Can J Anaesth 1991; 38:805-8. [PMID: 1742812 DOI: 10.1007/bf03036951] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
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48
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Double- and Single-Label Quantitative Autoradiography for Cerebral Physiology. ACTA ACUST UNITED AC 1990. [DOI: 10.1016/b978-0-12-185255-9.50009-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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49
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Williams LR, Leggett RW. Reference values for resting blood flow to organs of man. CLINICAL PHYSICS AND PHYSIOLOGICAL MEASUREMENT : AN OFFICIAL JOURNAL OF THE HOSPITAL PHYSICISTS' ASSOCIATION, DEUTSCHE GESELLSCHAFT FUR MEDIZINISCHE PHYSIK AND THE EUROPEAN FEDERATION OF ORGANISATIONS FOR MEDICAL PHYSICS 1989; 10:187-217. [PMID: 2697487 DOI: 10.1088/0143-0815/10/3/001] [Citation(s) in RCA: 219] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The lack of a reliable quantitative description of blood flow in man has hampered the development of accurate biokinetic models of essential elements, drugs, imaging agents, and carcinogens. In this paper we review and analyse data on blood flow and identify representative percentages of cardiac output and absolute blood flow rates to organs and tissues of man for use as reference values for biokinetic models. To keep the review and analysis to a manageable size we have limited attention to the resting state and have suggested reference values for absolute and relative flow rates only for adult males and females.
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Affiliation(s)
- L R Williams
- Health and Safety Research Division, Oak Ridge National Laboratory, Tennessee 37831-6383
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50
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Imai A, Meyer JS, Kobari M, Ichijo M, Shinohara T, Oravez WT. LCBF values decline while L lambda values increase during normal human aging measured by stable xenon-enhanced computed tomography. Neuroradiology 1988; 30:463-72. [PMID: 3226531 DOI: 10.1007/bf00339684] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Results of measurements of LCBF and L lambda values utilizing optimal CT-CBF methods under resting conditions are reported among thirty-two neurologically normal volunteers aged between 20 and 88 years. Measurements were made during inhalation of 26-30% stable xenon gas for 8 min and serial scanning utilizing a state-of the-art CT scanner with both eyes closed and ears unplugged. LCBF values for cortical gray matter were lowest in occipital cortex and highest in frontal cortex. Gray matter flow values were also high in subcortical structures with highest values measured in the thalamus. For white matter, highest flow values were measured in the internal capsule. Changes in LCBF and L lambda values were analyzed with respect to advancing age. Significant age-related declines in LCBF values were observed in occipital cortex and frontal white matter. Significant age-related increases in L lambda values were measured in frontal and temporal cortex, caudate nucleus and thalamus. Possible explanations are offered for these age-related increases in L lambda values for gray matter, such as accumulation of lipofuscin in neurons and relative compacting of gray matter with advancing age. The latter increases the numbers of nerve cells sampled per volume of gray matter measured.
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Affiliation(s)
- A Imai
- Cerebral Blood Flow Laboratory, Veterans Administration Medical Center, Houston, Texas
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