Foundational insights into the estimation of whole-body metabolic rate.

Since 2013, this journal has promoted the publication of thematic reviews (Taylor in Eur J Appl Physiol 113:1634, 2013), where leading groups were invited to review the critical literature within each of several sub-topics. The current theme is historically based, and is focussed on estimating the metabolic rate in humans. This review charts the development of our understanding of those methods, from the discovery of oxygen and carbon dioxide, to the introduction of highly sophisticated modern apparatus to examine the composition of expired gas and determine respiratory minute volume. An historical timeline links the six thematic vignettes on this theme. Modern advances have greatly enhanced data collection without significant decrements in measurement accuracy. At the same time, however, conceptual errors, particularly steady-state requirements, are too often ignored. Indeed, it is recognised that we often neglect the past, leading to errors in research design, experimental observations and data interpretation, and this appears to be increasingly prevalent within the open-access literature. Accordingly, the Editorial Board, in recognition of a widening gap between our experimental foundations and contemporary research, embarked on developing a number of thematic review series, of which this series is the first. The intent of each accompanying overview is to introduce and illuminate seminal investigations that led to significant scientific or intellectual breakthroughs, and to thereby whet the appetite of readers to delve more deeply into the historical literature; for it is only when the foundations are understood that we can best understand where we are now, and in which directions we should head.

Classical experiments in whole-body metabolism: closed-circuit respirometry.

As part of a series of reviews aimed at providing historical context to the study of whole-body metabolism, this article focuses on the technique of closed-circuit respirometry. Developed by nineteenth century physiologists Henri-Victor Regnault and Jules de Reiset, a constant-pressure closed-circuit calorimeter capable of measuring oxygen consumption and carbon dioxide production in small animals became the framework for future experiments on whole-body metabolism in humans. The volume-loss and volume-replenishment techniques can be used to indirectly assess energy expenditure using an oxygen reservoir; spirometers are simplistic in design but difficult to operate. Leaks, calibration errors, equilibration of gases and dead space are some of the major limitations of the methodology. Despite operational difficulties, closed-circuit respirometry is highly accurate and reproducible. Due to the bespoke nature of many closed-circuit systems, maintenance and repair is often troublesome. Compounded by technological advancement, closed-circuit techniques have become progressively outdated. Nevertheless, the classical experiments in whole-body metabolism played a pivotal role in furthering our understanding of basic human physiology and paved the way for current methodologies used in the field.

Direct calorimetry: a brief historical review of its use in the study of human metabolism and thermoregulation.

Direct calorimetry is the gold standard means of measuring human metabolic rate and its use has been fundamental for understanding metabolism in health and disease. While metabolic rate is now more commonly estimated indirectly from measures of the oxygen consumed during respiration, direct calorimetry provides the user with the unique capacity to quantify the heat produced from aerobic and anaerobic metabolism by measuring heat exchange between the body and the environment. This review provides a brief historical overview of the fundamental concepts which underlie direct calorimetry, of pioneer scientists which developed these concepts into functional pieces of equipment and the subsequent use of direct calorimetry to advance our understanding of energy balance, nutrition, and the pathogenesis of metabolic diseases. Attention is directed to seminal studies that successfully employed direct calorimetry to verify that the law of energy conservation also applies to human beings and to establish the validity of indirect calorimetry. Finally, we discuss the more recent use of direct calorimetry for the measurement of whole-body heat exchange and body heat storage in the study of human thermoregulation.

[Tadeusz Tucholski (1898-1940). A contribution to the scientific biography]. / Tadeusz Tucholski (1898-1940). Przyczynek do biografii naukowej.

Assistant professor Tadeusz Tucholski Ph.D., murdered in Katyn, was one of the most outstanding representatives of the younger generation of Polish physical chemist scholars of the interwar period. He published over 30 scientific papers in the field of physical and chemical properties of explosions, kinetics and catalysis and also toxicology and forensics. Thesere searches were partly performed at the University of Poznan, in the period 1926-1939, at the Faculty of Medicine of the Department of Physics where Tucholski was employed as a senior assistant and was the closest associate of professor S. Kalandyk, partly at the Department of Forensic Medicine headed by professor S. Horoszkiewicz in the chemical-toxicological laboratory which Tucholski ranin the years 1931-1939, partly at the Warsaw University of Technology in the Department of Explosives Technology of the Faculty of Chemistry headed by professor T. Urbanski, where he had been lecturing "On the latest theories of explosives" since 1937 and in 1934-35 in Cambridge, as a teaching fellow of the National Culture Fund, in Colloid Science Laboratory headed by professor E.K. Rideal. In 1903 Tucholski moved with his parents to Zabaykalye, in 1911--to Brazil. He returned to Poland in 1920, joined the Polish Army and with the 14th Polish Medium Regiment fought on the fronts of the Polish-Bolshevik War. He was drafted to the School of Pyrotechnics Foremen at Corps District Command number VII (Poznan). After graduating, Tucholski remained on active duty as a professional pyrotechnic: from 1921 to 1929 he was appointed the head of the Laboratory of Chemical and Pyrotechnic Ammunition Workshop No. 2 in Poznan and as an inspector of magazines of explosives. In 1927 he was transferred to the reserves, in 1932 after having graduated from the Officer Cadet School in Jarocin, Tucholski was appointed a second lieutenant in the Army Reserve, and later moved from the officers infantry corpsto the army ordnance corps. As part of his specialty, he constantly cooperated with the army. In the years 1937-1939,Tucholski was a technical adviser to the Ministry of Military Affairs and from August 1939--an independent researcher at the Institute of Armament Technology. He took part in the works of the Explosives Commission of the Military Technical Society. Tadeusz Tucholski was a self-taught man. He passed his A-level examsin course of his military service in October 1923 and began studying chemistry at the Faculty of Mathematics and Natural Sciences of the University of Poznan. He obtained his Master's degree in 1927, the rank and the degree of Ph.D. in the field of chemical sciences and physics in 1930. In 1936, he became the Associate Professor of physical chemistry of explosives at the Faculty of Chemistry at the University of Technology in Warsaw. Tucholski invented the method of the differential thermal analysis. He is the author of the widely used differential calorimeter which records the-processes of conversion of explosives during heating, presently known as the Differential Scanning Calorimeter.

Milk demystified by chemistry.

This article traces the decline of milk from a heavenly elixir to a tradeable food. Early cultures regarded milk not as a simple nutrient, but a living fluid. Heroes and gods were believed to have been nurtured by animals after being abandoned. Character traits were assumed to be transmitted by milk; infantile diseases were attributed to "bad milk", whereas "good milk" was used as a remedy. With chemical methods developed at the end of the 18th century, it became known that human milk was higher in sugar and lower in protein than cow's milk. During the 19th century, "scientific" feeding emerged that meant modifying cow's milk to imitate the proportion of nutrients in human milk. In Boston from 1893, Rotch initiated the "percentage" method, requiring a physician's prescription. In Paris from 1894, Budin sterilized bottled infant milk. In Berlin in 1898, Rubner measured oxygen and energy uptake by calorimetry, prompting feeding by calories, and Czerny introduced regulated feeding by the clock. These activities ignored the emotional dimension of infant nutrition and the anti-infective properties of human milk. They may have also enhanced the decline in breastfeeding, which reached an all-time low in 1971. Milk's demystification made artificial nutrition safer, but paved the way for commercially produced infant formula.

The collaboration of Antoine and Marie-Anne Lavoisier and the first measurements of human oxygen consumption.

Antoine Lavoisier (1743-1794) was one of the most eminent scientists of the late 18th century. He is often referred to as the father of chemistry, in part because of his book Elementary Treatise on Chemistry. In addition he was a major figure in respiratory physiology, being the first person to recognize the true nature of oxygen, elucidating the similarities between respiration and combustion, and making the first measurements of human oxygen consumption under various conditions. Less well known are the contributions made by his wife, Marie-Anne Lavoisier. However, she was responsible for drawings of the experiments on oxygen consumption when the French revolution was imminent. These are of great interest because written descriptions are not available. Possible interpretations of the experiments are given here. In addition, her translations from English to French of papers by Priestley and others were critical in Lavoisier's demolition of the erroneous phlogiston theory. She also provided the engravings for her husband's textbook, thus documenting the extensive new equipment that he developed. In addition she undertook editorial work, for example in preparing his posthumous memoirs. The scientific collaboration of this husband-wife team is perhaps unique among the giants of respiratory physiology.

Academic genealogy and direct calorimetry: a personal account.

Each of us as a scientist has an academic legacy that consists of our mentors and their mentors continuing back for many generations. Here, I describe two genealogies of my own: one through my PhD advisor, H. T. (Ted) Hammel, and the other through my postdoctoral mentor, Knut Schmidt-Nielsen. Each of these pathways includes distingished scientists who were all major figures in their day. The striking aspect, however, is that of the 14 individuals discussed, including myself, 10 individuals used the technique of direct calorimetry to study metabolic heat production in humans or other animals. Indeed, the patriarchs of my PhD genealogy, Antoine Lavoisier and Pierre Simon Laplace, were the inventors of this technique and the first to use it in animal studies. Brief summaries of the major accomplishments of each my scientific ancestors are given followed by a discussion of the variety of calorimeters and the scientific studies in which they were used. Finally, readers are encouraged to explore their own academic legacies as a way of honoring those who prepared the way for us.

Direct animal calorimetry, the underused gold standard for quantifying the fire of life.

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.

Survey of the year 2008: applications of isothermal titration calorimetry.

Isothermal titration calorimetry (ITC) is a fast, accurate and label-free method for measuring the thermodynamics and binding affinities of molecular associations in solution. Because the method will measure any reaction that results in a heat change, it is applicable to many different fields of research from biomolecular science, to drug design and materials engineering, and can be used to measure binding events between essentially any type of biological or chemical ligand. ITC is the only method that can directly measure binding energetics including Gibbs free energy, enthalpy, entropy and heat capacity changes. Not only binding thermodynamics but also catalytic reactions, conformational rearrangements, changes in protonation and molecular dissociations can be readily quantified by performing only a small number of ITC experiments. In this review, we highlight some of the particularly interesting reports from 2008 employing ITC, with a particular focus on protein interactions with other proteins, nucleic acids, lipids and drugs. As is tradition in these reviews we have not attempted a comprehensive analysis of all 500 papers using ITC, but emphasize those reports that particularly captured our interest and that included more thorough discussions we consider exemplify the power of the technique and might serve to inspire other users.

History of the calorie in nutrition.

The calorie was not a unit of heat in the original metric system. Some histories state that a defined Calorie (modern kcal) originated with Favre and Silbermann in 1852 or Mayer in 1848. However, Nicholas Clément introduced Calories in lectures on heat engines that were given in Paris between 1819 and 1824. The Calorie was already defined in Bescherelle's 1845 Dictionnaire National. In 1863, the word entered the English language through translation of Ganot's popular French physics text, which defined a Calorie as the heat needed to raise the temperature of 1 kg of water from 0 to 1 degrees C. Berthelot distinguished between g- and kg-calories by 1879, and Raymond used the kcal in a discussion of human energy needs in an 1894 medical physiology text. The capitalized Calorie as used to indicate 1 kcal on U.S. food labels derives from Atwater's 1887 article on food energy in Century magazine and Farmers' Bulletin 23 in 1894. Formal recognition began in 1896 when the g-calorie was defined as a secondary unit of energy in the cm-g-s measurement system. The thermal calorie was not fully defined until the 20th century, by which time the nutritional Calorie was embedded in U.S. popular culture and nutritional policy.