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Fick principle

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https://www.readbyqxmd.com/read/27911393/a-detailed-protocol-for-perspiration-monitoring-using-a-novel-small-wireless-device
#1
Kazuhiro Ogai, Masakazu Fukuoka, Kei-Ichiro Kitamura, Kiyoshi Uchide, Tetsu Nemoto
Perspiration monitoring can be utilized for the detection of certain diseases, such as thermoregulation and mental disorders, particularly when the patients are unaware of such disorders or are having difficulty expressing their symptoms. Until now, several devices for perspiration monitoring have been developed; however, such devices tend to have a relatively large exterior, considerable power consumption, and/or less sensitivity. Recently, we developed a small, wireless device for perspiration monitoring...
November 24, 2016: Journal of Visualized Experiments: JoVE
https://www.readbyqxmd.com/read/27881556/nitrite-and-s-nitrosohemoglobin-exchange-across-the-human-cerebral-and-femoral-circulation-relationship-to-basal-and-exercise-blood-flow-responses-to-hypoxia
#2
Damian M Bailey, Peter Rasmussen, Morten Overgaard, Kevin A Evans, Aske M Bohm, Thomas Seifert, Patrice Brassard, Morten Zaar, Henning B Nielsen, Peter Raven, Niels H Secher
BACKGROUND: -The mechanisms underlying red blood cell (RBC)-mediated hypoxic vasodilation remain controversial with separate roles for nitrite (NO2(-)) and S-nitrosohemoglobin (SNO-Hb) widely contested given their ability to transduce nitric oxide (NO) bioactivity within the microcirculation. To establish their relative contribution in vivo, we quantified arterial-venous (a-v) concentration gradients across the human cerebral and femoral circulation at rest and during exercise, an ideal model system characterized by physiological extremes of O2 tension and blood flow...
November 15, 2016: Circulation
https://www.readbyqxmd.com/read/27866929/long-term-outcomes-of-pulmonary-arterial-hypertension-under-specific-drug-therapy-in-eisenmenger-syndrome
#3
Sébastien Hascoët, Alban-Elouen Baruteau, Marc Humbert, Gérald Simonneau, Xavier Jais, Jérôme Petit, Daniela Laux, Olivier Sitbon, Virginie Lambert, André Capderou
BACKGROUND: The long-term effectiveness of pulmonary arterial hypertension-specific drug therapy (PAH-SDT) in Eisenmenger syndrome is controversial. We investigated short-term and long-term hemodynamic changes under PAH-SDT and their associations with outcomes in a bicentric cohort. METHODS: Over 20 years, we included 69 patients with congenital heart disease, an indexed pulmonary vascular resistance (PVRi) >8 WU·m(2), and 292 standardized catheterizations at baseline and after PAH-SDT initiation or intensification...
October 15, 2016: Journal of Heart and Lung Transplantation
https://www.readbyqxmd.com/read/27456179/comparison-of-pulsioflex%C3%A2-uncalibrated-pulse-contour-method-and-a-modified-fick-principle-with-transpulmonary-thermodilution-measurements-in-critically-ill-patients
#4
COMPARATIVE STUDY
J Grensemann, J M Defosse, C Wieland, U W Wild, F Wappler, S G Sakka
Monitoring of cardiac index (CI) by uncalibrated pulse contour (PC) methods has been shown to be inaccurate in critically ill patients. We tested accuracy and trending of a new pulse contour method and a modified Fick method using central venous oxygen saturation. We studied 21 critically ill and mechanically ventilated patients (age 20-86 years) monitored by PC (PulsioFlex®) and transpulmonary thermodilution (TPTD, PiCCO2®) as reference. At baseline, reference and PC-derived CI (CIPC) were recorded and CI obtained by Fick's method (FM, CIFICK)...
July 2016: Anaesthesia and Intensive Care
https://www.readbyqxmd.com/read/27292274/a-physiological-increase-in-maternal-cortisol-alters-uteroplacental-metabolism-in-the-pregnant-ewe
#5
O R Vaughan, K L Davies, J W Ward, M J de Blasio, A L Fowden
Fetal nutrition is determined by maternal availability, placental transport and uteroplacental metabolism of carbohydrates. Cortisol affects maternal and fetal metabolism but whether maternal cortisol concentrations within the physiological range regulate uteroplacental carbohydrate metabolism remains unknown. This study determined the effect of maternal cortisol infusion (1.2 mg kg(-1)  day(-1) iv. for 5 days, n = 20) on fetal glucose, lactate and oxygen supplies in pregnant ewes on day ∼130 of pregnancy (term = 145 days)...
June 13, 2016: Journal of Physiology
https://www.readbyqxmd.com/read/27258938/insulin-plays-a-permissive-role-for-the-vasoactive-effect-of-gip-regulating-adipose-tissue-metabolism-in-humans
#6
Meena Asmar, Lene Simonsen, Ali Asmar, Jens Juul Holst, Flemming Dela, Jens Bülow
CONTEXT AND OBJECTIVE: Glucose-dependent insulinotropic polypeptide (GIP) in combination with hyperinsulinemia increases blood flow and triglyceride (TAG) clearance in subcutaneous (sc) abdominal adipose tissue in lean humans. The present experiments were performed to further investigate the role of insulin for the vasoactive effect of GIP in adipose tissue metabolism and whether the vasodilatory effect of GIP is dependent on C-peptide. METHODS: Six lean healthy subjects were studied...
August 2016: Journal of Clinical Endocrinology and Metabolism
https://www.readbyqxmd.com/read/27074812/right-heart-catheterisation-may-be-cautiously-performed-through-a-mechanical-valve-prosthesis-in-the-tricuspid-position
#7
Stephen Pettit, Steven Tsui, Jayan Parameshwar
Right heart catheterisation (RHC) may be performed through a mechanical valve prosthesis in the tricuspid position using a partially inflated pulmonary artery flotation catheter. Preprocedural preparation should include an ex vivo trial with an identical valve prosthesis and the type of catheter to be used for the procedure. The operator should expect immediate unloading of the right ventricle due to catheter-associated tricuspid regurgitation, but it is possible to estimate pulmonary vascular resistance using the Fick principle...
2016: BMJ Case Reports
https://www.readbyqxmd.com/read/26997923/conceptual-foundations-of-diffusion-in-magnetic-resonance
#8
Cheng Guan Koay, Evren Özarslan
A thorough review of the q-space technique is presented starting from a discussion of Fick's laws. The work presented here is primarily conceptual, theoretical and hopefully pedagogical. We offered the notion of molecular concentration to unify Fick's laws and diffusion MRI within a coherent conceptual framework. The fundamental relationship between diffusion MRI and the Fick's laws are carefully established. The conceptual and theoretical basis of the q-space technique is investigated from first principles...
July 2013: Concepts in Magnetic Resonance. Part A, Bridging Education and Research
https://www.readbyqxmd.com/read/26956188/glucagon-like-peptide-1-does-not-have-acute-effects-on-central-or-renal-hemodynamics-in-patients-with-type-2-diabetes-without-nephropathy
#9
Ali Asmar, Lene Simonsen, Meena Asmar, Sten Madsbad, Jens J Holst, Erik Frandsen, Cedric Moro, Charlotte M Sorensen, Thomas Jonassen, Jens Bülow
During acute administration of native glucagon-like peptide-1 (GLP-1), we previously demonstrated central hemodynamic effects in healthy males, whereas renal hemodynamics, despite renal uptake of GLP-1 in excess of glomerular filtration, was unaffected. In the present study, we studied hemodynamic effects of GLP-1 in patients with type 2 diabetes under fixed sodium intake. During a 3-h infusion of GLP-1 (1.5 pmol·kg(-1)·min(-1)) or saline, intra-arterial blood pressure and heart rate were measured continuously, concomitantly with cardiac output estimated by pulse contour analysis...
May 1, 2016: American Journal of Physiology. Endocrinology and Metabolism
https://www.readbyqxmd.com/read/26918133/pharmacokinetic-pharmacodynamic-relationship-of-anesthetic-drugs-from-modeling-to-clinical-use
#10
REVIEW
Valerie Billard
Anesthesia is a combination of unconsciousness, amnesia, and analgesia, expressed in sleeping patients by limited reaction to noxious stimulations. It is achieved by several classes of drugs, acting mainly on central nervous system. Compared to other therapeutic families, the anesthetic drugs, administered by intravenous or pulmonary route, are quickly distributed in the blood and induce in a few minutes effects that are fully reversible within minutes or hours. These effects change in parallel with the concentration of the drug, and the concentration time course of the drug follows with a reasonable precision mathematical models based on the Fick principle...
2015: F1000Research
https://www.readbyqxmd.com/read/26598322/cardiac-output-and-vasodilation-in-the-vasovagal-response-an-analysis-of-the-classic-papers
#11
Wouter Wieling, David L Jardine, Frederik J de Lange, Michele Brignole, Henning B Nielsen, Julian Stewart, Richard Sutton
The simple faint is secondary to hypotension and bradycardia resulting in transient loss of consciousness. According to Ohm's law applied to the circulation, BP = SVR × CO, hypotension can result from a decrease in systemic vascular resistance (SVR), cardiac output (CO), or both. It is important to understand that when blood pressure (BP) is falling, SVR and CO do not change reciprocally as they do in the steady state. In 1932, Lewis, assuming that decreased SVR alone accounted for hypotension, defined "the vasovagal response" along pathophysiologic lines to denote the association of vasodilation with vagal-induced bradycardia in simple faint...
March 2016: Heart Rhythm: the Official Journal of the Heart Rhythm Society
https://www.readbyqxmd.com/read/26355542/modeling-of-the-bacillus-subtilis-bacterial-biofilm-growing-on-an-agar-substrate
#12
Xiaoling Wang, Guoqing Wang, Mudong Hao
Bacterial biofilms are organized communities composed of millions of microorganisms that accumulate on almost any kinds of surfaces. In this paper, a biofilm growth model on an agar substrate is developed based on mass conservation principles, Fick's first law, and Monod's kinetic reaction, by considering nutrient diffusion between biofilm and agar substrate. Our results show biofilm growth evolution characteristics such as biofilm thickness, active biomass, and nutrient concentration in the agar substrate...
2015: Computational and Mathematical Methods in Medicine
https://www.readbyqxmd.com/read/26334507/elevated-global-cerebral-blood-flow-oxygen-extraction-fraction-and-unchanged-metabolic-rate-of-oxygen-in-young-adults-with-end-stage-renal-disease-an-mri-study
#13
Gang Zheng, Jiqiu Wen, Hanzhang Lu, Yaxian Lou, Zhiying Pan, Wei Liu, Hui Liu, Xue Li, Zhe Zhang, Huijuan Chen, Xiang Kong, Song Luo, Xiaolu Jiang, Ya Liu, Zongjun Zhang, Long Jiang Zhang, Guang Ming Lu
OBJECTIVES: To noninvasively assess global cerebral blood flow (CBF), oxygen extraction fraction (OEF) and cerebral metabolic rate of oxygen (CMRO2) in young adults with end-stage renal disease (ESRD). METHODS: Thirty-six patients and 38 healthy volunteers were included and took part in MR examinations, blood and neuropsychological tests. CBF and OEF were measured by phase-contrast and T2-relaxation-under-spin-tagging MRI techniques, respectively. CMRO2 was computed from CBF, OEF and hematocrit according to Fick's principle...
June 2016: European Radiology
https://www.readbyqxmd.com/read/26319765/abomasal-amino-acid-infusion-in-postpartum-dairy-cows-effect-on-whole-body-splanchnic-and-mammary-glucose-metabolism
#14
C Galindo, M Larsen, D R Ouellet, G Maxin, D Pellerin, H Lapierre
Nine Holstein cows fitted with rumen cannulas and indwelling catheters in splanchnic blood vessels were used to study the effects of supplementing AA on milk lactose secretion, whole-body rate of appearance (WB-Ra) of glucose, and tissue metabolism of glucose, lactate, glycerol, and β-OH-butyrate (BHBA) in postpartum dairy cows according to a generalized randomized incomplete block design with repeated measures in time. At calving, cows were blocked according to parity (second and third or greater) and were allocated to 2 treatments: abomasal infusion of water (n=4) or abomasal infusion of free AA with casein profile (AA-CN; n=5) in addition to the same basal diet...
November 2015: Journal of Dairy Science
https://www.readbyqxmd.com/read/26113816/a-kinematic-model-for-3-d-head-free-gaze-shifts
#15
Mehdi Daemi, J Douglas Crawford
Rotations of the line of sight are mainly implemented by coordinated motion of the eyes and head. Here, we propose a model for the kinematics of three-dimensional (3-D) head-unrestrained gaze-shifts. The model was designed to account for major principles in the known behavior, such as gaze accuracy, spatiotemporal coordination of saccades with vestibulo-ocular reflex (VOR), relative eye and head contributions, the non-commutativity of rotations, and Listing's and Fick constraints for the eyes and head, respectively...
2015: Frontiers in Computational Neuroscience
https://www.readbyqxmd.com/read/25751103/effect-of-short-term-hyperglycemia-on-adipose-tissue-fluxes-of-selected-cytokines-in-vivo-during-multiple-phases-of-diet-induced-weight-loss-in-obese-women
#16
Michaela Siklova, Lene Simonsen, Jan Polak, Vladimir Stich, Jens Bülow
CONTEXT: Hyperglycemia is suggested to be one of the drivers of the proinflammatory state observed in obese and diabetic patients. OBJECTIVES: The objectives of the study was to investigate whether sc abdominal adipose tissue (scAT) could be one of the important sources of proinflammatory cytokines released in response to short-term hyperglycemia and whether this secretion capacity could be influenced by weight loss. DESIGN, PATIENTS, AND INTERVENTIONS: Output of cytokines and proteins of acute phase from scAT in response to a 3-hours hyperglycemic clamp was evaluated in nine obese women in vivo using Fick's principle...
May 2015: Journal of Clinical Endocrinology and Metabolism
https://www.readbyqxmd.com/read/25692831/-past-and-present-issues-of-the-pulmonary-circulation-in-the-general-university-hospital-in-prague
#17
Pavel Jansa, David Ambrož, Jaroslav Lindner
The development of right heart catheterization is closely connected not only with its pioneer Werner Forssmann but also with the University Hospital in Prague. Shortly after Forssmann´s pioneering performance of catheterization, Dr. Otto Klein measured cardiac output using the Fick´s principle in 11 patients in University Hospital. In the 60s and 70s of last century, there was established an research group represented by Severin Daum, Frantisek Boudik, Vlastimil Jezek, Alois Ourednik and Zdenek Suso at 2nd Internal Clinic of General Cardiopulmonary Hospital...
December 2014: Vnitr̆ní Lékar̆ství
https://www.readbyqxmd.com/read/25670826/renal-extraction-and-acute-effects-of-glucagon-like-peptide-1-on-central-and-renal-hemodynamics-in-healthy-men
#18
COMPARATIVE STUDY
Ali Asmar, Lene Simonsen, Meena Asmar, Sten Madsbad, Jens J Holst, Erik Frandsen, Cedric Moro, Thomas Jonassen, Jens Bülow
The present experiments were performed to elucidate the acute effects of intravenous infusion of glucagon-like peptide (GLP)-1 on central and renal hemodynamics in healthy men. Seven healthy middle-aged men were examined on two different occasions in random order. During a 3-h infusion of either GLP-1 (1.5 pmol·kg⁻¹·min⁻¹) or saline, cardiac output was estimated noninvasively, and intraarterial blood pressure and heart rate were measured continuously. Renal plasma flow, glomerular filtration rate, and uptake/release of hormones and ions were measured by Fick's Principle after catheterization of a renal vein...
April 15, 2015: American Journal of Physiology. Endocrinology and Metabolism
https://www.readbyqxmd.com/read/25593285/a-method-for-assessing-heterogeneity-of-blood-flow-and-metabolism-in-exercising-normal-human-muscle-by-near-infrared-spectroscopy
#19
Ioannis Vogiatzis, Helmut Habazettl, Zafeiris Louvaris, Vasileios Andrianopoulos, Harrieth Wagner, Spyros Zakynthinos, Peter D Wagner
Heterogeneity in the distribution of both blood flow (Q̇) and O2 consumption (V̇O2) has not been assessed by near-infrared spectroscopy in exercising normal human muscle. We used near-infrared spectroscopy to measure the regional distribution of Q̇ and V̇O2 in six trained cyclists at rest and during constant-load exercise (unloaded pedaling, 20%, 50%, and 80% of peak Watts) in both normoxia and hypoxia (inspired O2 fraction = 0.12). Over six optodes over the upper, middle, and lower vastus lateralis, we recorded 1) indocyanine green dye inflow after intravenous injection to measure Q̇; and 2) fractional tissue O2 saturation (StiO2) to estimate local V̇O2-to-Q̇ ratios (V̇o2/Q̇)...
March 15, 2015: Journal of Applied Physiology
https://www.readbyqxmd.com/read/25533515/feasibility-and-reproducibility-of-measurement-of-whole-muscle-blood-flow-oxygen-extraction-and-vo2-with-dynamic-exercise-using-mri
#20
Kory W Mathewson, Mark J Haykowsky, Richard B Thompson
PURPOSE: Develop an MRI method to estimate skeletal muscle oxygen consumption (VO2 ) with dynamic exercise using simultaneous measurement of venous blood flow (VBF) and venous oxygen saturation (SvO2 ). METHODS: Real-time imaging of femoral VBF using a complex-difference method was interleaved with imaging of venous hemoglobin oxygen saturation (SvO2 ) using magnetic susceptometry to estimate muscle VO2 (Fick principle). Nine healthy subjects performed repeated 5-watt knee-extension (quadriceps) exercise within the bore of a 1...
December 2015: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
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