Total body

Inhalation, injection, or body exposure to radium can cause cancer and other body disorders. The maximum permissible border in the total body for 226Ra is 7400 becquerel. 

Sulfur. Sulfur is present in every cell in the body, primarily in proteins containing the amino acids methionine, cystine, and cysteine. Inorganic sulfates and sulfides occur in small amounts relative to total body sulfur, but the compounds that contain them are important to metaboHsm (45,46). Sulfur intake is thought to be adequate if protein intake is adequate and sulfur deficiency has not been reported. Common food sources rich in sulfur are Hsted in Table 6. 

Iron. The total body content of iron, ie, 3—5 g, is recycled more efficientiy than other metals. There is no mechanism for excretion of iron and what Httie iron is lost daily, ie, ca 1 mg in the male and 1.5 mg in the menstmating female, is lost mainly through exfoHated mucosal, skin, or hair ceUs, and menstmal blood (74—76). Common food sources rich in iron and other trace elements are Hsted in Table 10. 

Pharmacokinetics is the study of how the body affects an adiriinistered dmg. It measures the kinetic relationships between the absorption, distribution, metaboHsm, and excretion of a dmg. To be a safe and effective dmg product, the dmg must reach the desired site of therapeutic activity and exist there for the desired time period in the concentration needed to achieve the desired effect. Too Htde of the dmg at such sites yields no positive effect ( MTC) leads to toxicity (see Fig. 1). For intravenous adininistration there is no absorption factor. Total body elimination includes both metabohc processing and excretion. 

Clinically, GM-CSF or G-CSF have been used to accelerate recovery after chemotherapy and total body or extended field irradiation, situations that cause neutropenia and decreased platelets, and possibly lead to fatal septic infection or diffuse hemorrhage, respectively. G-CSF and GM-CSF reproducibly decrease the period of granulocytopenia, the number of infectious episodes, and the length of hospitalization in such patients (152), although it is not clear that dose escalation of the cytotoxic agent and increased cure rate can be rehably achieved. One aspect of the effects of G-CSF and GM-CSF is that these agents can activate mature cells to function more efficiently. This may, however, also lead to the production of cytokines, such as TNF- a, that have some toxic side effects. In general, both cytokines are reasonably well tolerated. The side effect profile of G-CSF is more favorable than that of GM-CSF. Medullary bone pain is the only common toxicity. 

Fig. 1. Hypothetical kinetics of depletion of bone marrow (BM) stem cells following exposure to a lethal total-body irradiation (TBI) of 10 Gy (1000 rad) of...

The body excretes tritium with a biological half-life of 8—14 d (10.5 d average) (75), which can be reduced significantly with forced fluid intake. For humans, the estimated maximum permissible total body burden is 37 MBq (1 mCi). The median lethal dose (LD q) of tritium assimilated by the body is estimated to be 370 GBq (10 Ci). Higher doses can be tolerated with forced fluid intake to reduce the biological half-life. 

The concept of total body burden refers to the way a trace material accumulates in the human system. The components of the body that can store these materials are the blood, urine, soft tissue, hair, teeth, and bone. The blood and mine allow more rapid removal of trace materials than the soft tissue, hair, and bone (5). Accumulation results when trace materials are stored more rapidly than they can be eliminated. It can be reversed when the source of the material is reduced. The body may eliminate the trace material over a period of a few hours to days, or may take much longer— often years. 

The effect of accumulation in various systems depends greatly on the quantity of pollutants involved. Many pollutants can be detected at concentrations lower than those necessary to affect human health. For pollutants which are eliminated slowly, individuals can be monitored over long periods of time to detect trends in body burden the results of these analyses can then be related to total pollutant exposure. Following are two examples of air pollutants that contribute to the total body burden for lead and carbon monoxide. 

The absorption, distribution, and accumulation of lead in the human body may be represented by a three-part model (6). The first part consists of red blood cells, which move the lead to the other two parts, soft tissue and bone. The blood cells and soft tissue, represented by the liver and kidney, constitute the mobile part of the lead body burden, which can fluctuate depending on the length of exposure to the pollutant. Lead accumulation over a long period of time occurs in the bones, which store up to 95% of the total body burden. However, the lead in soft tissue represents a potentially greater toxicological hazard and is the more important component of the lead body burden. Lead measured in the urine has been found to be a good index of the amount of mobile lead in the body. The majority of lead is eliminated from the body in the urine and feces, with smaller amounts removed by sweat, hair, and nails. 

The second example of an air pollutant that affects the total body burden is carbon monoxide (CO). In addihon to CO in ambient air, there are other sources for inhalation. People who smoke have an elevated CO body burden compared to nonsmokers. Individuals indoors may be exposed to elevated levels of CO from incomplete combustion in heating or cooking stoves. CO gas enters the human body by inhalation and is absorbed directly into the bloodstream the total body burden resides in the circulatory system. The human body also produces CO by breakdown of hemoglobin. Hemoglobin breakdown gives every individual a baseline level of CO in the circulatory system. As the result of these factors, the body burden can fluctuate over a time scale of hours. 

The baseline level of COHb is—0.5% for most individuals. Uponexposure to elevated levels of atmospheric CO, the percentage of COHb will increase in a very predictable manner. Analytical techniques are available to measure COHb from <0.1 to >80% in the bloodstream, providing a very rapid method for defermining the total body burden. If elevated levels of CO are reduced, the percentage of COHb will decrease over a period of time. 

Under certain conditions, such as hyperbaria,airway heat losses can account for a considerable percentage of total body heat production (in some cases > 100%). Normally these threats are ameliorated by rapid moderation of inspired air temperature and humidity by exchanging heat and water vapor between the mucus and airstream in the upper airway. Recovering much of the heat and water vapor contained in expired air minimizes heat and water losses to the ambient environment and aids in whole-body thermoregulation. 

Du Bois area The total body surface area of a person. 

Long-term exposure limit (LTEL) An exposure limit requirement based on the assumption that the total body intake of a pollutant below this limit over an 8-hour working day will have no harmful effect on the worker over a working life. See also Maximum exposure limit (MEL), Occupational exposure limit (OEL), and Short-term exposure limit (STEL). 

Metabolic rate (M) The rate of transformation of chemical energy into heat and mechanical work by aerobic and anaerobic metabolic activities w ithin an organism, usually expressed per unit area of the total body surface, in met or W m -. 

The specimen has no specified size. Specimens for this test may consist of any standard fabricated test specimen or cut/punch pieces of sheet or machined sample. Specimens are mounted outdoors on racks slanted at 45° and facing south. It is recommended that concurrent exposure be carried out in many varied climates to obtain the broadest, most representative total body of data. Sample specimens are kept indoors as controls and for comparison. Reports of weathering describe all changes noted, areas of exposure, and period of time. 

Leptin is a cytokine produced and secreted by adipose tissue in proportion to the body fat content [3]. Mice and humans lacking leptin or its receptor develop a severe hyperphagia and a dramatic degree of obesity which is considerably more pronounced than that of the NDRKO mouse. Thus, leptin is the key adiposity signal in rodents and humans. Leptin secretion appears to reflect the metabolic status of the adipocyte rather than the sheer size of triglyceride deposits, and leptin levels may transiently be dissociated from total body fat. Nonetheless, over the course of a day with unrestricted food supply, plasma leptin levels reliably reflect the amount of total body fat. Local administration of leptin into the brain results in reduced food intake. The vast majority of patients with obesity have elevated serum levels of leptin. Thus, it is believed that the polygenic obesity is due to leptin resistance rather than to inadequate leptin secretion, or to a reduced blood/brain transport of the cytokine. 

Total body hypothermia Repair of vessel disease (brain aneurysm)... 

Bj = The 8-value of the j -th component of any set of body components. For example, hone collagen bone-apatite carbonate total body lipid, total body glycine muscle glycine etc. Each particular choice will have its own distinct equation. The set need not be complete— unlike D. 

Bacq ZM, Fischer P (1957) The action of various drugs on the suprarenal response of the rat to total-body x-irradiation. Radiat Res 7 365-372... 

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