Whole body composition

Chemical carcass analysis is considered the gold standard for accurate whole body composition analysis (13). It is, however, terminal and time consuming. The adiposity index can also be measured by dissecting and weighing of fat depots in individual animals (14). This method is also terminal and less accurate. The collection of visceral fat required can be particularly challenging as it is often spread throughout internal organs. 

Two imaging systems, dual energy X-ray absorptiometry scanning (DEXA) and magnetic resonance imaging (MRI), allow for longitudinal studies of whole body composition. DEXA measures bone mineral density and content, fat content, and lean content in anesthetized mice. Echo MRI from Echo Medical System, Houston, TX, is used to measure whole body composition parameters such as total body fat, lean mass, body fluids, and total body water in live mice without the need for anesthesia or sedation (15). The MRI technology is more rapid, less than a minute to scan one mouse, than DEXA which takes about 5 min per mouse. 

Tinsley, F. C., Taicher, G. Z. and Heiman, M. L. (2004) Evaluation of a quantitative magnetic resonance method for mouse whole body composition analysis. Obes Res 12, 150-160. 

The application field of bioimpedance is very wide—from single-cell measurements with micro- and nanoelectrodes to whole-body composition analysis from healthy to ischemic, pathological, and dead tissue. We have selected some typical bioimpedance application examples. 

In vivo analysis is characterized by limitations in radiation dose, compensated by large samples and large detectors. For the measurement of whole-body composition NAA has been accepted as a reference method by which other methods can be assessed [16]. 

The nondestructive ability of NAA, particularly in the form of PGNAA, permits in vivo analysis with much greater reliability than by any other method. In this way information on whole-body composition may be obtained with impeccable accuracy and well-known precision. 

To the clinician, the accurate measurement of total body water (TBW) can provide indirect information concerning whole body composition and energy balance. Desiccation measurements performed on eviscerated guinea pigs in 1945 [270] led to the almost universal acceptance of the fact that lean body mass (LBM) was of constant composition — and additionally, contained all of the body water. Thus the extracellular water associated with adipose tissue was neglected and the water content of lean body mass taken as 73.2%. The following simple formula, which was readily applied to man, provided an indirect estimate of body fat ... 

Typically, a satisfying rqjroducibility of the order of 1-3 % is obtained. An interesting spin-off of this approach is the whole body composition analysis (BCA) of small animals. ... 

Campbell, R.G. and A.C. Dunkin, 1983. The effects of energy intake and dietary protein on nitrogen retention, growth performance, body composition and some aspects of energy metabolism of baby pigs. Br. J. Nutr. 49, 221-230. Kovner, I.,Taicher and A. Mitchell, 2009. Calibration and validation of EchoMRI whole body composition analysis based on chemical analysis of piglets. Int. J. Body Comp. Res. (in press). 

Taicher, G.Z., EC. Tinsley, A. Reiderman and M.L. Heiman, 2003. Quantitative magnetic resonance (QMR) method for bone and whole body composition analysis. Anal. Bioanal. Chem. 377, 990-1002. 

Goldstein, R.M., M.E. Brigham, and J.C. Stauffer. 1996. Comparison of mercury concentrations in liver, muscle, whole bodies, and composites of fish from the Red River of the North. Canad. Jour. Fish. Aquat. Sci. 53 244-252. 

The terminator of drug action is, of course, elimination. Elimination is a composite of excretion (kidney, etc.) and biotransformation (metabolism). The primary measure of drug elimination from the whole body is clearance, CLt, defined as the volume of plasma fluid removed of drug per unit time. It is a direct measure of the loss of the drug from the system and can be calculated from Eq. (3.5) after IV administration of a dose of the drug. 

Phase analysis and texture of the metal particles. Iron powders are constituted of the a-Fe phase with a body-centered cubic (bcc) lattice, whereas Fe-Co powders appear as a mixture of three phases that are quite similar to those of pure metals (bcc for a-Fe and a mixture of hep and fee for cobalt) (6). In the Fe.Nil(m system, a single fee phase is observed over the whole available composition range U s 25) with a linear dependence of the lattice parameter versus z, which shows the existence of a fee solid solution as already evidenced for the Co.rNiu)o-. system (33). The XRD patterns of the Fe [CovNi(1()o -,v)] i - powders depend on the composition An fee phase is always observed either as a single phase or as the main phase a second hep phase with weak and broad lines appears for a cobalt content x > 35 a third body-centered cubic (hcc) phase can be evidenced when x > 80. 

Metabolic Transit of 14C-Lysinoalanine in Other Species. In mice and in hamsters, the metabolic transit of lysinoalanine is not very different from that of rats except in the composition of some urinary catabolites (113) and the level of the radioactivity remaining in the kidneys (see Table VIII). In quails the feces contained small amounts of lysinoalanine (6-15%) and only two important catabolites. The urines of mice and hamsters contained two catabolites less than those of rats (see Figure 5), and although mice and hamsters do not develop nephrocytomegaly, they presented the same kind of retention of radioactivity in the kidney cells as rats. This retention in the medular part of the kidneys is well observed on the whole-body autoradiographies of Figure 2 however, in mice and hamsters, this retention is quantitatively less important than in rats (see Table VIII). 

The characteristic feature of CM chondrules is the coexistence of roughly equal amounts of high-temperature anhydrous silicates (olivine and pyroxene) and low-temperature hydrous clay minerals. It is generally believed that the clay minerals were formed by aqueous alteration of the high-temperature phases, either in space or in the parent body. Figure 7 shows that the phyllosilicate matrix is systematically enriched in the heavy isotopes of oxygen, relative to the whole rock. The tie-lines between whole-rock compositions and matrix compositions have slopes of —0.7, implying that the water reservoir had a composition with more positive than the silicate reservoir. Clayton and Mayeda (1999) showed that the observed patterns can be accounted for with a simple closed-system hydration reaction at temperatures near 0°C,... 

Because so many factors in addition to lipid composition can affect POP accumulation (discussed above), some researchers currently favor using whole body lipid and POP measurements to estimate risk of effects from POP exposure. This is essentially a lipid-adjusted CBR. A recent example of this approach is shown in detail by Meador et al.122. These authors used a number of studies from the literature on appropriate life stages of salmon to determine a lipid-adjusted threshold for effects for a wide range of endpoints after PCB exposure. This threshold number was then compared to levels of PCBs measured in wild juvenile salmon from a contaminated estuary, and many of the fish, on the lipid-adjusted basis, were determined to be at risk of effects from environmental exposure to PCBs. 

Shearer, K., T. Asgard, G. Andorsdottir and G. Aas. Whole body elemental and proximate composition of Atlantic salmon (Salmo salaf) during the life cycle. J. Fish Biol. 44 785-797, 1994. 

The kidneys have a key role in the maintenance of body homeostasis and effectively regulate whole-body biochemistry by the reactive elimination of a wide variety of unwanted organic and inorganic compounds in the urine, i.e. the constancy of the internal environment is maintained at the expense of varying urinary composition. This variation in composition is, therefore, a reflection of a large number of biochemical processes taking place both in the kidney and elsewhere in the body and, as such, NMR urinalysis is potentially of enormous diagnostic importance. 

No histological changes occurred in the liver of adolescent male rats that were whole-body exposed to 0 or 900 ng/m Aroclor 1242 vapor 23 hours/day for 30 days (Casey et al. 1999). The generation of the vapor-phase test atmosphere was based entirely on the evaporation of a liquid PCB mixture using a system that did not create aerosol droplets, and the concentration and congener composition of the test atmosphere was well characterized. Limitations of this study include only one exposure level and liver end point and a relatively small number of animals (8/group) however, uptake of PCBs in the liver was confirmed by tissue analysis, and the exposure was sufficient to induce effects in other tissues, including the thyroid, which is known to be particularly sensitive to PCBs. 

In studying the finer aspects of the regulation of the cell, we found it necessary to take into consideration what is, for the cell, the outside world of the body as a whole. Now that we have come so far as to begin to build up a biochemical picture of the whole body, it becomes necessary for us to take one final step. For the cell, the external environment is provided by the body, a homeostatic system which maintains the constancy of its internal composition and thus enables the cell to survive as part of an integrated whole,... 

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