Body fat

They are widely distributed in vegetable lipids, and in the body fat of animals, though animals cannot synthesize them. They have vitamin E activity and can protect unsaturated lipids against oxidation. Four are found naturally ... 

Growth Performance Response. The consistent net effect of anaboHc steroid implant use in growing mminants appears to be increased rate of protein and Hve weight gain, and increased Hve weight at which carcass or empty body fat concentration equals that in nonimplanted cattie thus increasing their potential mature size. Increased feed intake is frequentiy observed. 

DDT is stored ia body fats and is secreted ia milk as DDT, DDD, and DDE with traces of their o,p -isonieis. Levels of these compounds ia the body tissues of United States inhabitants have declined slowly from ca 12 ppm ia 1970 as a result of sharply curtailed usage. 

In Eigure 1, the lower edge of the drawing is the flesh side of the hide. The hide, as it is removed from an animal, has body fat and a thin membrane separating the hide from the fat and flesh of the body of the animal. The area near the inside of the hide is made up of the heaviest fibers of the hide. 

One way to lose weight is to exercise. Playing tennis for half an hour consumes about 225 kcal of energy. How long would you have to play tennis to lose one pound of body fat (One gram of body fat is equivalent to 32 kj of energy.)... 

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. 

Decreased lipid content of the skin Increased body fat decreased body water... 

The gender of an individual may influence the action of some drugp. Women may require a smaller dose of some drugp than men. This is because many women are smaller than men and have a body fat-and-water ratio different from that of men. 

Ethanol distributes rapidly, with concentrations in body water 10 times higher than in body fat. The tissues with the greatest blood supply equdibrate most rapidly with arterial blood circulation. Shortly after alcohol ingestion, the ethanol concentration in the brain is higher than the venous concentration. 

The dramatic decrease in the morbidity and mortality of HIV-infected individnals in the last decade, due to the wide use of HAART, has been somewhat tempered by the emergence of mid-long term toxicities. A characteristic body fat redistribntion and metabolic changes, inclnding dyslipidemia and insnlin resistance, are amongst the most prevalent and worrisome consequences (Carr et al. 2003). As HIV-infected individnals have increasing life expectancies, the risk for cardiovascnlar complications has emerged as an important canse of morbidity and mortality and preventive measnres should be considered to minimize their impact (Weber et al. 2006). 

Starvation or disease can lead to rapid release of the stored xenobiotic and to delayed toxic effects. In one well-documented case in the Netherlands (see Chapter 5), wild female eider ducks (Somateria mollissima) experienced delayed neurotoxicity caused by dieldrin. The ducks had laid down large reserves of depot fat before breeding, and these reserves were run down during the course of egg laying. Dieldrin concentrations quickly rose to lethal levels in the brain. Male eider ducks did not lay down and mobilize body fat in this way and did not show delayed neurotoxicity due to dieldrin. 

Would you expect to find this compound to be excreted in urine or stored in body fat Explain your reasoning. BHT is nontoxic to humans. 

Once in your blood, your liver changes much of the trichloroethylene into other chemicals. The majority of these breakdown products leave your body in the urine within a day. You will also quickly breathe out much of the trichloroethylene that is in your bloodstream. Some of the trichloroethylene or its breakdown products can be stored in body fat for a brief period, and thus may build up in your body if exposure continues. For more information on trichloroethylene in your body, see Chapter 2. 

Several studies of tissue distribution in humans after inhalation exposure to trichloroethylene report levels in the blood (Astrand and Ovrum 1976 Monster et al. 1976 Muller et al. 1974). Once in the bloodstream, trichloroethylene may be transported rapidly to various tissues where it will likely be metabolized. Trichloroethylene was detected in the blood of babies at birth after the mothers had received trichloroethylene anesthesia (Laham 1970), and detectable levels (concentrations not reported) have been found in the breast milk of mothers living in urban areas (Pellizzari et al. 1982). Post-mortem analyses of human tissue from persons with unspecified exposure revealed detectable levels of trichloroethylene (<1-32 pg/kg wet tissue) in most organs (McConnell et al. 1975). The relative proportions varied among individuals, but the major sites of distribution appeared to be body fat and the liver. 

Sato et al. (1991) expanded their earlier PBPK model to account for differences in body weight, body fat content, and sex and applied it to predicting the effect of these factors on trichloroethylene metabolism and excretion. Their model consisted of seven compartments (lung, vessel rich tissue, vessel poor tissue, muscle, fat tissue, gastrointestinal system, and hepatic system) and made various assumptions about the metabolic pathways considered. First-order Michaelis-Menten kinetics were assumed for simplicity, and the first metabolic product was assumed to be chloral hydrate, which was then converted to TCA and trichloroethanol. Further assumptions were that metabolism was limited to the hepatic compartment and that tissue and organ volumes were related to body weight. The metabolic parameters, (the scaling constant for the maximum rate of metabolism) and (the Michaelis constant), were those determined for trichloroethylene in a study by Koizumi (1989) and are presented in Table 2-3. 

Metabolic differences betw een humans and other animals may account for some of the interspecies differences in specific organ toxicity of trichloroethylene (see below). Among humans, sexual differences due mainly to the effects of body fat content on trichloroethylene absorption are expected based on PBPK modeling (see Section 2.3.5). 

Differences among individuals can partially explain the differences in the before workshift and end of workshift levels of trichloroethylene and its metabolites. Increased respiration rate during a workday, induced by physical workload, has been shown to affect levels of unchanged trichloroethylene more than its metabolites, while the amount of body fat influences the levels of the solvent and its metabolites in breath, blood, and urine samples before workshift exposure (Sato 1993). Additionally, liver function affects measurements of exhaled solvent at the end of workshift increased metabolism of trichloroethylene will tend to decrease the amount exhaled after a workshift. Increased renal function would affect levels of TCA and trichloroethanol in blood before a workshift in the same way, but it probably would not affect urine values between the begiiming and the end of the workshift because of the slow excretion rate of TCA. 

Correlations of exposure with other measures of body burden are often difficult and their results are consequently less conclusive. For example, trichloroethylene was present at unspecified levels in eight of eight samples of mother s milk from four urban areas in the United States (Pellizzari et al. 1982). Whole-blood specimens from 121 men and 129 women with no known exposure to trichloroethylene had levels from nondetectable to 1.5 ppb (Antoine et al. 1986). Post-mortem analyses of human tissue revealed body fat... 

One of the main determinants of the number of subjects required to reach the desired statistical power is the precision of the measurement tool utilized. More precise measurements will reduce the number of subjects required. As an example, if a study is being conducted to assess the influence of a dietary supplement on body fat, several measurement tools could be used to assess this outcome. These tools range from low levels of cost and precision (e.g. skinfold measurements) to moderate levels (e.g. bioelectrical impedance) to high levels of cost and precision (dual x-ray absorptiometry - DXA). A study that uses skinfold measurements to measure the outcome will require many more subjects than one which employs DXA. Therefore, it is often less expensive in total to utilize a more expensive measurement tool, because the more precise tool will allow the study to have sufficient power with a smaller number of subjects. 

COCKERIL D c, Bucci L R (1987) Increases in muscle grith and decreases in body fat associated with a nntritional supplemental program. Chirop. Sports Ed, I (2) 73. 

Diazepam Being extremely lipophilic, diazepam penetrates quickly into the CNS, but can rapidly redistribute into body fat and muscle. This results in a faster decline in CNS levels and early recurrence of seizures. It is dosed at 5 to 10 mg (or 0.15 mg/kg) and infused no faster than 5 mg/minute. Repeated doses can be given every 5 minutes until seizure activity stops or toxicities are seen (e.g., respiratory depression). Diazepam can also be administered as a rectal suppository, making it possible for non-medical personnel to provide rapid therapy for seizures that develop at home or in public areas.11 The adult dose is 10 mg given rectally and this dose may be repeated once if necessary. Diazepam is erratically absorbed via the intramuscular route therefore, IM administration is not recommended. 

Hegele, R. A., Anderson, C., Young, T. K. Connelly, P. W. (1999). G-protein beta3 subunit gene splice variant and body fat distribution in Nunavut Inuit. Genome Res., 9, 972-7. 

When DDT is fed to animals, even in small quantities, there is an accumulation of the compound in the tissues, particularly the fat. Telford and Guthrie (18), Orr and Mott (13), Woodward et al. (20, 21), and Laug and Fitzhugh (9) have demonstrated that DDT will accumulate in certain tissues and in milk fat of domestic and laboratory animals. Marsden and Bird (12) found that DDT was toxic to turkeys in concentrations above 0.075% of the diet, and that turkeys fed the insecticide for 7 to 8 weeks stored DDT in their fat at concentrations ranging from 4 to 8 times that in the diet. Rubin et al. (14) reported that hens fed 0.062% DDT in their diet for 12 weeks showed reduced egg production with lowered hatchability. At one half this concentration there was a detrimental effect on egg production, but hatchability was not seriously affected. The hens were killed by doses of 0.125% DDT. The insecticide was found in the eggs in quantities much smaller than in the body fat. Harris et al. (8) have shown that DDT will accumulate in considerable quantities in the fat of lambs fed DDT-treated hay. Small amounts of the insecticide were found in other tissues. 

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