https://staff.blog.ui.ac.id/hsuryadi/files/2012/02/ROS_RNS.pdf

Free radicals and antioxidants in normal physiological functions and human disease

The fat content of the human body has physiological and medical importance. It may influence morbidity and mortality, it may aIter the effectiveness of drugs and anaesthetics, and it may affect the ability to withstand exposure to cold and starvation. Thus the measurement of the total body fat provides useful information. In many people, but by no means everyone, a moderately satisfactory estimate of the body fat content can be obtained from the height and weight. However, for more precise evaluation several methods are available which give a reasonably accurate measure of body fat both in normal subjects and in individuals with unusual body builds. Most of these methods are based on the assumption that the body can be considered to consist of two compartments of relatively constant composition but which are distinctly different; these compartments are: (I) the body fat, which includes the entire content of chemical fat or lipids in the body, and (2) the fat-free mass (FFM), which includes all the rest of the body apart from fat. The body fat compartment is anhydrous, contains no potassium and has a fairly constant density of about 0.90 x 103 kg/m3. The fat-free compartment on the other hand probably has a fairly constant density of about 1.10 x 103 kg/m3, a potassium content of about 68 mequiv./kg in males (about 10% less in females) and a water content of about 720 g/kg. Thus measurement of body density or of total body K or of total body water allows a calculation of the relative proportion of these two compartments in the body and therefore also of the total fat content. The accuracy of these measures, however, is limited by the variability of the composition and density of the fat-free compartment in different individuals. In particular, individuals with a relatively high or

/pdf/body-fat-assessed-from-total-body-density-and-its-estimation-2c3s39jrgr.pdf

Body fat assessed from total body density and its estimation from skinfold thickness: measurements on 481 men and women aged from 16 to 72 years

Metabolism provides a basis for using first principles of physics, chemistry, and biology to link the biology of individual organisms to the ecology of populations, communities, and ecosystems. Metabolic rate, the rate at which organisms take up, transform, and expend energy and materials, is the most fundamental biological rate. We have developed a quantitative theory for how metabolic rate varies with body size and temperature. Metabolic theory predicts how metabolic rate, by setting the rates of resource uptake from the environment and resource allocation to survival, growth, and reproduction, controls ecological processes at all levels of organization from individuals to the biosphere. Examples include: (1) life history attributes, including devel- opment rate, mortality rate, age at maturity, life span, and population growth rate; (2) population interactions, including carrying capacity, rates of competition and predation, and patterns of species diversity; and (3) ecosystem processes, including rates of biomass production and respiration and patterns of trophic dynamics. Data compiled from the ecological literature strongly support the theoretical predictions. Even- tually, metabolic theory may provide a conceptual foundation for much of ecology, just as genetic theory provides a foundation for much of evolutionary biology.

/pdf/toward-a-metabolic-theory-of-ecology-1dxmg8xr3n.pdf

Toward a metabolic theory of ecology

Lung volumes are subdivided into static and dynamic lung volumes. Static lung volumes are measured by methods which are based on the completeness of respiratory manoeuvres, so that the velocity of the manoeuvres should be adjusted accordingly. The measurements taken during fast breathing movements are described as dynamic lung volumes and as forced inspiratory and expiratory flows.

### 1.1 Static lung volumes and capacities

The volume of gas in the lung and intrathoracic airways is determined by the properties of lung parenchyma and surrounding organs and tissues, surface tension, the force exerted by respiratory muscles, by lung reflexes and by the properties of airways. The gas volumes of thorax and lung are the same except in the case of a pneumothorax. If two or more subdivisions of the total lung capacity are taken together, the sum of the constituent volumes is described as a lung capacity. Lung volumes and capacities are described in more detail in § 2.

#### 1.1.1 Determinants

Factors which determine the size of the normal lung include stature, age, sex, body mass, posture, habitus, ethnic group, reflex factors and daily activity pattern. The level of maximal inspiration (total lung capacity, TLC) is influenced by the force developed by the inspiratory muscles (disorders include e.g. muscular dystrophy), the elastic recoil of the lung (disorders include e.g. pulmonary fibrosis and emphysema) and the elastic properties of the thorax and adjacent structures (disorders include e.g. ankylosis of joints). The level of maximal expiration (residual volume, RV) is determined by the force exerted by respiratory muscles (disorders include e.g. muscle paralysis), obstruction, occlusion and compression of small airways (disorders include e.g. emphysema) and by the mechanical properties of lung and thorax (disorders include diffuse fibrosis, kyphoscoliosis).

Assessing the total lung capacity is indispensable in establishing a restrictive ventilatory defect or in diagnosing abnormal lung distensibility, as may occur in patients …

Lung volumes and forced ventilatory flows

The reduction of oxygen to water proceeds via one electron at a time. In the mitochondrial respiratory chain, Complex IV (cytochrome oxidase) retains all partially reduced intermediates until full reduction is achieved. Other redox centres in the electron transport chain, however, may leak electrons to oxygen, partially reducing this molecule to superoxide anion (O2−•). Even though O2−• is not a strong oxidant, it is a precursor of most other reactive oxygen species, and it also becomes involved in the propagation of oxidative chain reactions. Despite the presence of various antioxidant defences, the mitochondrion appears to be the main intracellular source of these oxidants. This review describes the main mitochondrial sources of reactive species and the antioxidant defences that evolved to prevent oxidative damage in all the mitochondrial compartments. We also discuss various physiological and pathological scenarios resulting from an increased steady state concentration of mitochondrial oxidants.

https://physoc.onlinelibrary.wiley.com/doi/pdf/10.1111/j.1469-7793.2003.00335.x

Mitochondrial formation of reactive oxygen species.

Publisher Summary This chapter reviews oxygen poisoning and X-irradiation. Exposure to unphysiologically high tensions of oxygen causes irreversible damage to living matter. The problem of oxygen toxicity is important in clinical medicine and in deep-sea diving. A consideration of various isolated reports leads to the hypothesis that oxygen poisoning and the primary action of X-irradiation have a common basis of action: possibly the formation of the oxidizing free radicals OH, and O2H, and H2O2. The evidence of a protective effect of coenzyme A against X-rays and against oxygen toxicity in experiments is incomplete and needs further studies. The chapter presents a table reporting the effect of X-rays and protective agents on oxygen poisoning in mice.

https://science.sciencemag.org/content/sci/119/3097/623.full.pdf

Oxygen Poisoning and X-irradiation: A Mechanism in Common

Mechanics of breathing in man.

A barometric method for measurement of ventilation of newborn infants is described. Experiments with cats are reported to show the degree of accuracy obtainable at present. The variation from standard methods was found to average±1 per cent. Minute volume, frequency, and tidal volume of premature infants measured by the barometric method are within the range of such measurements made by plethysmographic methods. The barometric principle deserves further study since it offers the possibility of securing ventilation data with a minimum disturbance to the infant.

A barometric method for measuring ventilation in newborn infants.

It is remarkable that physiologists have paid so little attention in the past to the mechanics of breathing that no adequate data are now on record concerning the pressure-volume characteristics of the chest and lungs in normal men. The literature contains innumerable investigations of the various fractions of the lung volume and the vital capacity and also a number of observations concerning the positive and negative pressures that can be exerted but these two sets of data have not been correlated. There is little indication of how the vital capacity or other lung volumes vary with pressures nor, conversely, of how the pressures vary with the volume at which they are developed. Likewise there is little information concerning the relaxation pressures at different lung volumes and the relation between these data and the venous pressure. In this paper data are presented concerning the positive and negative pressures which can be produced by voluntary effort, and a diagram which gives a comprehensive picture of all these mechanical factors. Since completing this work we have discovered similar diagrams from papers by Rohrer (1916) and Senner (1921) each based upon measurements on a single individual as well as a partially similar effort by Jacquet (1908) and Bernouilli (1911). Three types of measurement were used for the pressure-volume diagram of the lung : (1) maximum expiratory and inspiratory pressures at different lung volumes, (2) relaxation pressures at different lung volumes, (3) vital capacities, tidal air, and inspiratory and expiratory reserves at different lung pressures. METHODS. (1) M aximum inspiratory and expiratory pressures. Measurements were made with a recording mercury manometer connected to a one hole rubber stopper cut to fit one nostril. The other nostril was held closed while the subject expired or inspired with maximum force. The nose was used in preference to the mouth in order to avoid all possibility of using the cheeks. It was found to be important to keep the subject from bending over in his effort to

The pressure-volume diagram of the thorax and lung

THIS work is the result of a suggestion by Prof. A. V. Hill that the heat production of muscles allowed to shorten and do work should be reinvestigated by means of the improved myothermal methods which he and Hartree(l) have developed and have applied with such success to muscles in isometric contraction. As shown by their work on the difficult problem of the thermo-elastic effect(2), this technique makes it possible to allow muscles to shorten without errors due to slipping over the junctions provided strict precautions be taken to insure uniformity of temperature. The primary object of the experiments was to measure the maximum efficiency attainable with a frog's muscle under ideal conditions of load, etc. This has been done and the result shows an astonishingly low efficiency. The experiments, moreover, have led to important modifications of some of the fundamental and accepted principles of muscle physiology. In particular it can now be shown that there is a fairly good quantitative relation between the heat production of muscles and the work which they perform, and that a muscle which does work liberates, ipsofacto, an extra supply of energy which does not appear in an isometric contraction. Having reached this rather novel point of view, it was a surprise to find that in its essentials it was not new but was urged by A. Fick 30 years ago, without, however, a satisfactory experimental basis. For this reason the history of the subject is of interest. Heidenhain(3) first showed that if increasing weights were hung on a muscle (not after-loaded) then the heat production caused by the contraction of the muscie and the lifting of the weight increased with increase in the weight. Both Fick(4) and Heidenhain(3) added to this fact the observation that the heat also increased with the load even if the muscle always contracted from the same initial position. This was accomplished either by after-loading the muscle or by the use of Fick's

https://physoc.onlinelibrary.wiley.com/doi/pdf/10.1113/jphysiol.1923.sp002115

Wallace O. Fenn

Papers

Oxygen Poisoning and X-irradiation: A Mechanism in Common

Mechanics of breathing in man.

A barometric method for measuring ventilation in newborn infants.

The pressure-volume diagram of the thorax and lung

A quantitative comparison between the energy liberated and the work performed by the isolated sartorius muscle of the frog