SEARCH · Search PubMed
Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
This article deals with the thorny issue of official authority to search for drugs in the bodies of suspected drug offenders. Relevant Israeli cases and legislation are discussed and a draft bill proposed.
Human nitrosating capacity has been monitored using proline; however, N-nitrosothiazolidine 4-carboxylic acid (NTCA; N-nitrosothioproline), one of the predominant N-nitroso compounds in human urine, is also nonmutagenic and, presumably, noncarcinogenic. Thioproline is nitrosated about 1000 times faster than proline in vitro, and NTCA is excreted into the urine without being metabolized. We have therefore proposed thioproline as an effective nitrite-trapping agent in the human body. Recently, we found thioproline in various cooked foods, including cod and dried shiitake mushrooms. In the study reported here, we evaluate the nitrite trapping capacity of thioproline in a male nonsmoking volunteer ingesting NO3- and eating a controlled diet. The highest level of NTCA excreted, 5.89 mumol, was measured after the subject ingested 6 mmol NO3- followed by 0.45 mmol (60 mg) thioproline. We estimated the effective amount of nitrite, defined as the actual amount of nitrite participating in nitrosation in the stomach, to be 0.3% of the NO3- ingested. Thus, the effective amount of NO2- for 6 mmol NO3- ingested was calculated to be 18 mumol, and 33% of this nitrite was trapped by ingestion of 0.45 mmol thioproline. We conclude that thioproline is a most sensitive probe for evaluating human nitrosating capacity and an effective nitrite-trapping agent.
The Human Engineering Division of the Armstrong Laboratory (USAF); the Mallinckrodt Institute of Radiology; the Washington University School of Medicine; and the Lister-Hill National Center for Biomedical Communication, National Library of Medicine are sponsoring a working group on electronic imaging of the human body. Electronic imaging of the surface of the human body has been pursued and developed by a number of disciplines including radiology, forensics, surgery, engineering, medical education, and anthropometry. The applications range from reconstructive surgery to computer-aided design (CAD) of protective equipment. Although these areas appear unrelated, they have a great deal of commonality. All the organizations working in this area are faced with the challenges of collecting, reducing, and formatting the data in an efficient and standard manner; storing this data in a computerized database to make it readily accessible; and developing software applications that can visualize, manipulate, and analyze the data. This working group is being established to encourage effective use of the resources of all the various groups and disciplines involved in electronic imaging of the human body surface by providing a forum for discussing progress and challenges with these types of data.
The absolutely accurate measurement of adiposity in a living organism is undoubtedly difficult. Although a number of methods have been developed, none has been proven to be both theoretically and empirically an unquestioned validating criterion method for the estimation of human body composition. In the present study, a new method was introduced that is rapid, safe, and relatively simple to administer and has the added advantage of not requiring a measurement of the underwater weight. The procedure involves the direct measurement of body volume by applying a sulfur hexafluoride (SH)-dilution method with the subject only standing in a 375-1 closed chamber (Shimazu BSF-100) that is filled with air and 0.26 liters of SH. Results indicate that body volume (r = 0.998) and body density (r = 0.819) measured by the SH method were highly correlated to those determined by underwater weighing. Reproducibility of body volume was found to be almost perfect (i.e., 0.995) with the regression coefficient of 1.03 and the intercept of -1.5. Variability (CV = 0.7%) in body volume of a 45-year-old reference man measured by SH method was very similar to variation (CV = 0.6%) in mass volume of the 60-1 prototype. The calculated percent body fat (r = 0.851) and fat-free mass (0.962) with some correction of body density were also highly correlated to those determined by underwater weighing. We suggest that SH method may be useful for assessment of human body composition.
Human body fluids such as mixed saliva, erythrocyte, plasma and mature breast milk were analysed for selenium (Se) and Se-dependent glutathione peroxidase (GSH-Px), which is the only active form of Se known in man. Selenium-dependent GSH-Px activity was detected for the first time in human mixed saliva. Body fluid GSH-Px, Se and protein contents expressed in terms of volume increased in the order, saliva less than milk less than plasma less than erythrocyte. However, the sequence of increase for GSH-Px (U/mg protein) and GSH-Px-bound Se (%) was plasma less than milk less than erythrocyte less than saliva, and that for Se (ng/mg protein) was erythrocyte less than saliva less than plasma less than milk. Significant positive correlations were found between GSH-Px and Se contents and between protein and Se contents expressed per volume for human saliva, erythrocyte and the whole human fluids investigated. Positive correlations between erythrocyte and plasma Se (ng/mg protein) and between plasma and saliva GSH-Px-bound Se (%) were also significant.
The venous architecture of the integument and the underlying deep tissues was studied in six total-body human fresh cadavers and a series of isolated regional studies of the limbs and torso. A radiopaque lead oxide mixture was injected, and the integument and deep tissues were dissected and radiographed. The sites of the venous perforators were plotted and traced to their underlying parent veins that accompany the source (segmental) arteries. A series of cross-sectional studies were made in one subject to illustrate the course of the perforators between the integument and the deep tissues. The veins were dissected under magnification to identify the site and orientation of the valves. Results revealed a large number of valveless (oscillating) veins within the integument and deep tissues that link adjacent valved venous territories and allow equilibration of flow and pressure throughout the tissue. Where choke arteries define the arterial territories, they are matched by boundaries of oscillating veins in the venous studies. The venous architecture is a continuous network of arcades that follow the connective-tissue framework of the body. The veins converge from mobile to fixed areas, and they "hitchhike" with nerves. The venous drainage mirrors the arterial supply in the deep tissues and in most areas of the integument in the head, neck, and torso. In the limbs, the stellate pattern of the venous perforators is modified by longitudinal channels in the subdermal network. However, when an island flap is raised, these longitudinal channels are disconnected, and once again the arterial and venous patterns match. Our venous studies add strength to the angiosome concept. Where source arteries supply a composite block of tissue, we have demonstrated radiologically and by microdissection that the branches of these arteries are accompanied by veins that drain in the opposite direction and return to the same locus. Hence each angiosome consists of matching arteriosomes and venosomes. The clinical implications of these results are discussed with particular reference to the design of flaps, the delay phenomenon, venous free flaps, the pathogenesis of flap necrosis, the "muscle pump," varicose veins, and venous ulceration.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Temperature profiles within the human body are highly dependent on the geometry and inhomogeneity of the body. Physical parameters such as density and heat conductivity of the various tissues and variables such as blood flow and metabolic heat production of different organs are spatially distributed and thereby influence the temperature profiles within the human body. Actual physiological knowledge allows one to take into account up to 54 different spatially distributed values for each parameter. An adequate representation of the anatomy of the body requires a spatial three-dimensional grid of at least 0.5-1.0 cm. This is achieved by photogrammetric treatment of three-dimensional anatomic models of the human body. As a first essential result, the simulation system has produced a realistic picture of the topography of temperatures under neutral conditions. Compatibility of reality and simulation was achieved solely on the basis of physical considerations and physiological data base. Therefore the simulation is suited to the extrapolation of temperature profiles that cannot be obtained experimentally.
Nature, as we know it, obeys the Laws of thermodynamics. The investigation into the energetics of the human body is an application of these laws to the human biological system. The First Law of thermodynamics, which has been verified many times in experiments on the human body, expresses the constraints of the conservation of energy and the equivalence between work and heat. It considers any energy change as equally possible, not in the least taking into account the irreversibility of a given process. The implications of the Second Law of thermodynamics, on the other hand, have never been examined in detail on the human body. This Law defines the direction in which an energy transformation can occur, as well as the equilibrium conditions of the systems. In this paper, we present the main results of a body of research, aimed at calculating the non-reversible processes of the human body system by means of using the entropy concept as the main operator in applying the Second Law on physical and sometimes even non-physical systems. Determination of body composition was based on Magnetic Resonance Imaging (MRI). In addition, we used direct as well as indirect calorimetric techniques to measure the heat transfers between the human body and its environment, as well as oxygen consumption and carbon dioxide production. These measurements allowed us to compute various energy balances of a human body at rest. Furthermore, we studied also several aspects of energy exchange of the human body during muscular work.
Entropy inflow and outflow for the naked human body in basal conditions in the respiration calorimeter due to infrared radiation, convection, evaporation of water and mass-flow are calculated by use of the energetic data obtained by Hardy & Du Bois. Also, the change of entropy content in the body is estimated. The entropy production in the human body is obtained as the change of entropy content minus the net entropy flow into the body. The entropy production thus calculated becomes positive. The magnitude of entropy production per effective radiating surface area does not show any significant variation with subjects. The entropy production is nearly constant at the calorimeter temperatures of 26-32 degrees C; the average in this temperature range is 0.172 J m-2 sec-1 K-1. The forced air currents around the human body and also clothing have almost no effect in changing the entropy production. Thus, the entropy production of the naked human body in basal conditions does not depend on its environmental factors.
Explore the source record for details and available documents.
Sodium magnetic resonance imaging of the human body in vivo has been tried and its clinical application is considered. A short T2 imaging algorithm with total volume excitation and a specialized RF coil focused to the region of interest have been adopted to improve the signal-to-noise ratio. Using a 1.5-T human body imaging system, several important organs including heart, liver, gallbladder, kidney, and spine have been examined to demonstrate their sodium concentration in vivo.
The Hanavan mathematical model of the human body was updated utilizing Clauser et al.'s multi-step weight distribution regression equations. The influence of these equations upon the predicted segment weights, specific gravities and principal moments of inertia of 30 adult male athletes was compared to that of Barter's regression equations employed in the original model. Both methods resulted in descrepancies between actual body weight and the predicted sum of the segment weights with Barter's equations consistently underestimating total body weight by an average of 2.03% and Clauser et al.'s overestimating it by 4.59%. Proportional distribution of the discrepancies produced corrected segment weights which were used in the Hanavan model. Clauser et al.'s equations predicted heavier trunks and thighs, and lighter heads, upper arms, forearms and hands with these differences being reflected in the specific gravities and principal moments of intertia. While it was not possible to establish the definite superiority of Clauser et al.'s equations in the prediction of body segment parameters, it is suggested from inferential evidence that they be used in subsequent biomechanical investigations of adult male athletes which involve the Hanavan model. It is also recommended that continued efforts be made to refine the Hanavan human body model.
Stun guns, shock batons and cattle prods are electric shock devices which can be used as weapons against the human body. Stun guns cause temporary incapacitation of the body whereas the other devices do not. The electrical outputs of examples of each type of device were measured using a digital storage oscilloscope at the moment when the device was discharged across resistors chosen to simulate the resistance of the human body. The outputs from the stun guns and the non-incapacitating devices have characteristic waveform shapes and magnitudes: significantly, the peak current from the stun guns is two orders of magnitude greater than from the other devices. To understand the possible hazardous effects of these outputs on the human body, the output parameters were related to the available information on the effects of electric currents on the human body and on the electro-immobilization of farm animals.
Among the methods simulating weightlessness, effects on the human body, head-down tilting and water immersion are very useful. The purpose of the present investigation was to carry out a comparative study of water balance and water-protein composition of the blood using the above two methods to simulate the physiological effects typical of an acute stage of weightlessness adaptation. The results of the 7-d head-down tilting and immersion experiments allow the following conclusions: More pronounced changes in water balance and water-protein composition of the blood during immersion seem to indicate that immersion produces a greater effect on the human body; The pattern of changes during immersion and tilting suggests that the adaptation period to immersion takes a longer time; These findings give evidence that immersion, compared with head-down tilting, reproduces more closely effects of acute adaptation to simulated weightlessness.
The weighing of the human body under water is an application of Archimedes' law. Fat being lighter than water or than the structures of lean body mass, body fat can be measured by determining the specific gravity of the human body; that is, by underwater weighing. Body fat has been determined in an "ideal" sample of 14 men and 23 women, all aged 20 years. Testing against a reference measure of body fat makes it possible to test the validity of some anthropometric measurements and of some indices of obesity. These indices offer no advantages over anthropometric measurements.
This paper reports the changes of the EEG of human bodies during saturation exposure at different depths to different mixed gases. The results of the research show that the most obvious on EEG was the appearance of diffused slow waves, usually theta waves of 4-7 times/s, and delta waves of 2-3 times/s within individual subjects. The EEG changes at 50 m were more obvious than those at 36.5 m. With the prolonging of time under high pressure, the EEG had some improvements, for instance, the slow waves decreased and the alpha waves increased. There was a certain relationship between these changes and the symptoms which appeared in the human body. The chief factor of the EEG changes is due to the effect of nitrogen narcosis during the oxygen-nitrogen diving experiment. In addition, carbon dioxide retention under the high pressure is also a factor of the EEG changes, because repeated inhaling of CO2-dense mixtures could aggravate the EEG changes and the reduction of carbon dioxide in humans by hyperventilation could improve abnormal EEGs. The main changes of the EEG during the helium-oxygen exposure at 302 m were the increase of theta waves, and even of delta waves, the decrease in alpha rhythm and the decline of amplitude of alpha waves. Increased theta index and decreased alpha index could be seen at the depth of 302 m. Under any of the above-mentioned pressure conditions when slow waves characteristic of abnormal changes appeared in the EEGs, the EEGs could be temporarily improved by photic stimulation, i.e. slow waves disappeared and alpha waves reappeared. When photic stimulation was over, alpha waves disappeared and slow waves reappeared. It was indicated that abnormal changes of the EEG under high pressure were a kind of temporary and reversible changes of the brain function.