Biomarker for Energy Intake
Dale A. Schoeller, Margriet S. Westerterp-Plantenga in Advances in the Assessment of Dietary Intake, 2017
Energy intake is a function of energy requirement as determined by resting energy expenditure and activity-induced energy expenditure. Resting energy expenditure can be measured or predicted with an equation based on weight, height, age, and gender of the subject. Activity-induced energy expenditure (AEE) can be estimated with an accelerometer for movement registration. The validity of these measures for estimating energy intake is presented with respirometry assessed resting energy expenditure and doubly-labeled water assessed total energy expenditure as a reference. Prediction of resting energy expenditure based on subject sex, weight, height, and age with equations is applicable for most subjects. For some ethnicities or for subjects with an exceptional physical activity level like athletes, measurement of body composition is indicated; to use a fat-free mass-based equation. For activity-induced energy expenditure, a valid sensor for body movement should allow explaining most of the variation as observed with the reference; doubly-labeled water assessed total energy expenditure.
Mitochondrial Dysfunction and Allergic Disease
Shamim I. Ahmad in Handbook of Mitochondrial Dysfunction, 2019
While the above mentioned studies have mechanistically explored the role of mitochondrial dysfunction in airway inflammatory cells and the airway epithelial cells in model systems, there is also evidence that these pathways are operational in humans. Eleven patients with a history of grass pollen allergic rhinitis were recruited and 2 nasal challenges of either grass pollen extract or placebo were carried out in a randomized order, 4 weeks apart. Peripheral blood was collected from the subjects before and 6 and 24 hours post the challenge, followed by isolation of peripheral blood mononuclear cells (PBMCs). Mitochondrial respiratory function of the PBMCs was analyzed by measuring maximal respiration rate and specific mitochondrial respiratory chain complex activities using high resolution respirometry. Exposure to pollen led to significant reduction of the combined activities of mitochondrial complex I, III, and IV, 6 hours after the allergen challenge. This effect was, however, restored 24 hours post the challenge. The nasal allergen challenge had deleterious effect on the mitochondrial respiratory chain complex I activity, while the complex II, III, and IV activities were not significantly impaired. Additionally, there was a significant reduction in the mitochondrial coupling of oxidation and phosphorylation 6 hours after the allergen exposure. This effect of allergen exposure to the mitochondrial function of circulating cells of allergic patients is the first report to highlight the mitochondrial function involvement in a systemic manner in pollen allergy pathophysiology (Qi et al. 2017).
The Twentieth Century
Arturo Castiglioni in A History of Medicine, 2019
The study of the respiratory (oxidative) metabolism of tissue slices surviving in media of known composition has materially extended the knowledge of intimate phases of metabolism and the activity of enzymes in numerous metabolic reactions. Joseph Barcroft’s studies (1908) on the dissociation curve of hemoglobin (see his Respiratory Function of the Blood, 1914) and Otto Warburg’s direct method illustrate the value of respirometry in permitting experiments when only small amounts of valuable material, such as enzymes or isotopically labelled organic compounds, are available. K. linderstr0m-lang’s application of the Cartesian diver principle in an ultramicromanometer will doubtless foster further progress.
Panax ginseng root, not leaf, can enhance thermogenic capacity and mitochondrial function in mice
Published in Pharmaceutical Biology, 2020
Su-hui Wu, Han-bing Li, Gen-Lin Li, Yue-juan Qi, Juan Zhang, Bai-yan Wang
At day 0, day 9 and day 18 of the experiment, rest metabolic rates (quantified as oxygen consumption rate, VO2) and CO2 production (VCO2) were measured by an open-flow respirometry system (TSE Labmaster Calorimetry System, Germany) with an overall flow rate of 0.8 L/min and a sample flow rate of 0.39 L/min. RER were calculated as VCO2/VO2 (Arch et al. 2006). An incubator (Sanyo, MIR-554) was used to maintain the respiratory chambers (TSE, type I for mice, volume 2.7 L) at a constant temperature (30 ± 0.5 °C) within the TNZ of mouse (Pan et al. 2014). Real time ambient temperature in the incubator was recorded during metabolic measurements. All measurements were made between 08:00 and 20:00 h every day. Body weights were recorded before and after every measurement.
Intestinal microbiota drives cholestasis-induced specific hepatic gene expression patterns
Published in Gut Microbes, 2021
Oriol Juanola, Mohsin Hassan, Pavitra Kumar, Bahtiyar Yilmaz, Irene Keller, Cédric Simillion, Cornelius Engelmann, Frank Tacke, Jean-François Dufour, Andrea De Gottardi, Sheida Moghadamrad
The oxygen consumption rates (OCRs) in homogenates from frozen livers were measured with a Seahorse Extracellular Flux (XF) ‐96 Bioanalyzer (Agilent Technologies, Santa Clara, CA, USA). Frozen liver tissues were thawed and washed two times with ice-cold PBS. The ‘Respirometry in Frozen Samples (RIFS)’ protocol was adapted from Acin-Perez R et al. 2020.44 Approximately, 50 mg of tissue was cut into small pieces and homogenized in MAS buffer (70 mM sucrose, 220 mM mannitol, 5 mM KH2PO4, 5 mM MgCl2, 1 mM EGTA, 2 mM HEPES, pH 7.4) with 20 strokes in a glass Dounce homogenizer. The homogenate was centrifuged at 1,000 g for 10 min at 4°C, the supernatant was collected and protein concentration was determined by PierceTM BCA assay (Thermo Fisher Scientific, Rockford, IL, USA). In Seahorse XF96 microplate, 10 µg (proteins) of homogenate was loaded into in 20 µl of MAS. The loaded plate was centrifuged at 2,000 g for 5 min at 4°C and an additional 130 µl of MAS containing cytochrome c (10 µg/ml) was added to each well. Substrates were delivered by port A (pyruvate + malate (5 mM each)) or NADH (1 mM), or 5 mM succinate + rotenone (5 mM + 2 µM). The inhibitors, Rotenone and antimycin A (2 µM + 4 µM) were delivered by port B. TMPD + ascorbic acid (0.5 mM + 1 mM) at port C; and azide (50 mM) at port D.
Stabilization protects islet integrity during respirometry in the Oroboros Oxygraph-2K analyzer
Published in Islets, 2022
Justin J. Crowder, Ziqian Zeng, Alissa N. Novak, Nathan J. Alves, Amelia K. Linnemann
Recent studies utilizing the Seahorse and Oxygraph platforms have provided a wealth of information on metabolic characteristics of rodent and human islets.5–10 However, concerns have been raised regarding the delicate and dynamic nature of intact islets within metabolic analysis instruments.11 For example, respirometry analysis with the Oxygraph-2 K system (Oroboros) includes a stir bar that circulates buffer and reagents. This creates a forceful interaction between the stir bar and islets that may disrupt islet integrity, leading to data that is more indicative of respiration within individual cells, rather than intact islets. Islet stabilization within Oxygraph chambers may therefore provide protection to these fragile tissues, leading to similar benefits of intact islet analysis as those seen in Seahorse islet plates.
Related Knowledge Centers
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