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Journal of Applied Physiology... Feb 2019For thermal physiologists, calorimetry is an important methodological tool to assess human heat balance during heat or cold exposures. A whole body direct calorimeter... (Review)
Review
For thermal physiologists, calorimetry is an important methodological tool to assess human heat balance during heat or cold exposures. A whole body direct calorimeter remains the gold standard instrument for assessing human heat balance; however, this equipment is rarely available to most researchers. A more widely accessible substitute is partitional calorimetry, a method by which all components of the conceptual heat balance equation-metabolic heat production, conduction, radiation, convection, and evaporation-are calculated separately based on fundamental properties of energy exchange. Since partitional calorimetry requires relatively inexpensive equipment (vs. direct calorimetry) and can be used over a wider range of experimental conditions (i.e., different physical activities, laboratory or field settings, clothed or seminude), it allows investigators to address a wide range of problems such as predicting human responses to thermal stress, developing climatic exposure limits and fluid replacement guidelines, estimating clothing properties, evaluating cooling/warming interventions, and identifying potential thermoregulatory dysfunction in unique populations. In this Cores of Reproducibility in Physiology (CORP) review, we summarize the fundamental principles underlying the use of partitional calorimetry, present the various methodological and arithmetic requirements, and provide typical examples of its use. Strategies to minimize estimation error of specific heat balance components, as well as the limitations of the method, are also discussed. The goal of this CORP paper is to present a standardized methodology and thus improve the accuracy and reproducibility of research employing partitional calorimetry.
Topics: Animals; Body Temperature Regulation; Calorimetry; Energy Metabolism; Humans; Models, Biological; Predictive Value of Tests; Reproducibility of Results; Sweating; Thermogenesis
PubMed: 30496710
DOI: 10.1152/japplphysiol.00191.2018 -
Nature Communications Jun 2020Non-invasive and label-free calorimetry could become a disruptive technique to study single cell metabolic heat production without altering the cell behavior, but it is...
Non-invasive and label-free calorimetry could become a disruptive technique to study single cell metabolic heat production without altering the cell behavior, but it is currently limited by insufficient sensitivity. Here, we demonstrate microfluidic single-cell calorimetry with 0.2-nW sensitivity, representing more than ten-fold enhancement over previous record, which is enabled by (i) a low-noise thermometry platform with ultralow long-term (10-h) temperature noise (80 μK) and (ii) a microfluidic channel-in-vacuum design allowing cell flow and nutrient delivery while maintaining a low thermal conductance of 2.5 μW K. Using Tetrahymena thermophila as an example, we demonstrate on-chip single-cell calorimetry measurement with metabolic heat rates ranging from 1 to 4 nW, which are found to correlate well with the cell size. Finally, we perform real-time monitoring of metabolic rate stimulation by introducing a mitochondrial uncoupling agent to the microchannel, enabling determination of the spare respiratory capacity of the cells.
Topics: Basal Metabolism; Calorimetry; Microfluidic Analytical Techniques; Microfluidics; Mitochondria; Oxygen Consumption; Single-Cell Analysis; Temperature; Tetrahymena thermophila; Thermal Conductivity
PubMed: 32532969
DOI: 10.1038/s41467-020-16697-5 -
Journal of Physiotherapy Oct 2019
Topics: Calorimetry, Indirect; Humans; Psychometrics
PubMed: 31477499
DOI: 10.1016/j.jphys.2019.07.002 -
Frontiers in Bioscience (Landmark... Jan 2016Occurrence of guanine-rich sequences throughout the genome at specific locations like chromosomal ends (telomeres), promoters and Untranslated regions (UTR's) is very... (Review)
Review
Occurrence of guanine-rich sequences throughout the genome at specific locations like chromosomal ends (telomeres), promoters and Untranslated regions (UTR's) is very well documented. Quite recently, visualization of guanine-quadruplex in human and mammalian cells have also provided a very significant evidence for the in vivo existence of guanine-quadruplex, reconfirming their biological relevance in cellular processes like replication, transcription, recombination, etc. Guanine quadruplexes have enormous potential of exhibiting various topologies which differ, by number/ orientation of strands or loop orientations etc. Some relatively new polymorphic structures like 3+1 quadruplex, G-triplex, and Tri-G-quadruplex have also been proposed for the guanine-rich sequences. Various biochemical and biophysical techniques have been used to characterize these multistranded DNA structures. An extensive review of the mechanistic models of the already existing and newly emerging techniques is actually required, which may further facilitate our understanding about these structures. This review aims to summarize some of these techniques along with their requirements and limitations, which might further give some insights for the fine tuning of the solution and environmental conditions needed for facilitating guanine-quadruplex formation.
Topics: Calorimetry; Crystallography, X-Ray; Electrophoresis; G-Quadruplexes; Spectrum Analysis
PubMed: 26709787
DOI: 10.2741/4402 -
Nature Reviews. Drug Discovery Oct 2016Over the past 25 years, biophysical technologies such as X-ray crystallography, nuclear magnetic resonance spectroscopy, surface plasmon resonance spectroscopy and... (Review)
Review
Over the past 25 years, biophysical technologies such as X-ray crystallography, nuclear magnetic resonance spectroscopy, surface plasmon resonance spectroscopy and isothermal titration calorimetry have become key components of drug discovery platforms in many pharmaceutical companies and academic laboratories. There have been great improvements in the speed, sensitivity and range of possible measurements, providing high-resolution mechanistic, kinetic, thermodynamic and structural information on compound-target interactions. This Review provides a framework to understand this evolution by describing the key biophysical methods, the information they can provide and the ways in which they can be applied at different stages of the drug discovery process. We also discuss the challenges for current technologies and future opportunities to use biophysical methods to solve drug discovery problems.
Topics: Animals; Biophysical Phenomena; Calorimetry; Drug Design; Drug Discovery; Drug Evaluation, Preclinical; High-Throughput Screening Assays; Humans; Pharmaceutical Preparations; Surface Plasmon Resonance
PubMed: 27516170
DOI: 10.1038/nrd.2016.123 -
Comparative Biochemistry and... Mar 2011Direct animal calorimetry, the gold standard method for quantifying animal heat production (HP), has been largely supplanted by respirometric indirect calorimetry owing... (Review)
Review
Direct animal calorimetry, the gold standard method for quantifying animal heat production (HP), has been largely supplanted by respirometric indirect calorimetry owing to the relative ease and ready commercial availability of the latter technique. Direct calorimetry, however, can accurately quantify HP and thus metabolic rate (MR) in both metabolically normal and abnormal states, whereas respirometric indirect calorimetry relies on important assumptions that apparently have never been tested in animals with genetic or pharmacologically-induced alterations that dysregulate metabolic fuel partitioning and storage so as to promote obesity and/or diabetes. Contemporary obesity and diabetes research relies heavily on metabolically abnormal animals. Recent data implicating individual and group variation in the gut microbiome in obesity and diabetes raise important questions about transforming aerobic gas exchange into HP because 99% of gut bacteria are anaerobic and they outnumber eukaryotic cells in the body by ∼10-fold. Recent credible work in non-standard laboratory animals documents substantial errors in respirometry-based estimates of HP. Accordingly, it seems obvious that new research employing simultaneous direct and indirect calorimetry (total calorimetry) will be essential to validate respirometric MR phenotyping in existing and future pharmacological and genetic models of obesity and diabetes. We also detail the use of total calorimetry with simultaneous core temperature assessment as a model for studying homeostatic control in a variety of experimental situations, including acute and chronic drug administration. Finally, we offer some tips on performing direct calorimetry, both singly and in combination with indirect calorimetry and core temperature assessment.
Topics: Animals; Body Temperature Regulation; Calibration; Calorimetry; Calorimetry, Indirect; Drug Tolerance; Energy Metabolism; History, 18th Century; History, 19th Century; History, 20th Century; History, 21st Century; Homeostasis; Humans; Hypothermia, Induced; Models, Animal; Nitrous Oxide
PubMed: 20427023
DOI: 10.1016/j.cbpa.2010.04.013 -
Current Opinion in Structural Biology Oct 2010Higher throughput thermodynamic measurements can provide value in structure-based drug discovery during fragment screening, hit validation, and lead optimization.... (Review)
Review
Higher throughput thermodynamic measurements can provide value in structure-based drug discovery during fragment screening, hit validation, and lead optimization. Enthalpy can be used to detect and characterize ligand binding, and changes that affect the interaction of protein and ligand can sometimes be detected more readily from changes in the enthalpy of binding than from the corresponding free-energy changes or from protein-ligand structures. Newer, higher throughput calorimeters are being incorporated into the drug discovery process. Improvements in titration calorimeters come from extensions of a mature technology and face limitations in scaling. Conversely, array calorimetry, an emerging technology, shows promise for substantial improvements in throughput and material utilization, but improved sensitivity is needed.
Topics: Calorimetry; Drug Discovery; High-Throughput Screening Assays; Reproducibility of Results; Thermodynamics
PubMed: 20888754
DOI: 10.1016/j.sbi.2010.09.001 -
Obesity (Silver Spring, Md.) Sep 2020Whole-room indirect calorimeters have been used to study human metabolism for more than a century. These studies have contributed substantial knowledge to the assessment... (Review)
Review
Whole-room indirect calorimeters have been used to study human metabolism for more than a century. These studies have contributed substantial knowledge to the assessment of nutritional needs and the regulation of energy expenditure and substrate oxidation in humans. However, comparing results from studies conducted at different sites is challenging because of a lack of consistency in reporting technical performance, study design, and results. In May 2019, an expert panel was convened to consider minimal requirements for conducting and reporting the results of human whole-room indirect calorimeter studies. We propose Room Indirect Calorimetry Operating and Reporting Standards, version 1.0 (RICORS 1.0) to provide guidance to ensure consistency and facilitate meaningful comparisons of human energy metabolism studies across publications, laboratories, and clinical sites.
Topics: Calorimetry, Indirect; Energy Metabolism; Humans; Reference Standards
PubMed: 32841524
DOI: 10.1002/oby.22928 -
Journal of Food and Drug Analysis Jun 2021Quality control (QC) is the most important key issue in the pharmaceutical industry to ensure the quality of drug products. Many analytical instruments and techniques in... (Review)
Review
Quality control (QC) is the most important key issue in the pharmaceutical industry to ensure the quality of drug products. Many analytical instruments and techniques in pharmaceutical analysis are applied to assess the quality and quantity of the drugs. In the current and future trends, a combination of digitization, automation and hyphenation with high throughput on-line performance will be the topics for the future of pharmaceutical QC. The hyphenated analytical techniques have recently received great attention as unique means to solve complex analytical problems in a short period of time. This review article is an update on the recent potential applications of hyphenated technique developed from the coupling of a rapid separation or induction technique (differential scanning calorimetry; DSC) and an on-line spectroscopic (Fourier transform infrared; FTIR) detection technology to carry out an one-step solid-state analysis in pharmaceutical formulation developments, including (1) intramolecular condensation of pharmaceutical polymers, (2) intramolecular cyclization of drugs and sweetener, (3) polymorphic transformation of drugs and excipients, (4) drug-polymer (excipient) interaction, (5) fast cocrystal screening and formation. This simultaneous DSC-FTIR microspectroscopy can also provide an easy and direct method for one-step screening and qualitative detection of drug stability in real time.
Topics: Calorimetry, Differential Scanning; Drug Stability; Excipients; Spectroscopy, Fourier Transform Infrared
PubMed: 35696204
DOI: 10.38212/2224-6614.3345 -
Analytica Chimica Acta Feb 2011Aptamers are single stranded DNA or RNA molecules that have been selected using in vitro techniques to bind target molecules with high affinity and selectivity, rivaling... (Review)
Review
Aptamers are single stranded DNA or RNA molecules that have been selected using in vitro techniques to bind target molecules with high affinity and selectivity, rivaling antibodies in many ways. In order to use aptamers in research and clinical applications, a thorough understanding of aptamer-target binding is necessary. In this article, we review methods for assessing aptamer-protein binding using separation based techniques such as dialysis, ultrafiltration, gel and capillary electrophoresis, and HPLC; as well as mixture based techniques such as fluorescence intensity and anisotropy, UV-vis absorption and circular dichroism, surface plasmon resonance, and isothermal titration calorimetry. For each method the principle, range of application and important features, such as sample consumption, experimental time and complexity, are summarized and compared.
Topics: Aptamers, Nucleotide; Calorimetry; Chromatography, High Pressure Liquid; Circular Dichroism; Electrophoresis, Capillary; Protein Binding; Proteins; Spectrometry, Fluorescence; Spectrophotometry, Ultraviolet; Surface Plasmon Resonance
PubMed: 21237304
DOI: 10.1016/j.aca.2010.10.032