Adipose tissue measuring

The growth of animals can be defined as an increase in mass of whole body, tissue(s), organ(s), or ceU(s) with time. This type of growth can be characterized by morphometric measurements eg, skeletal muscle or adipose tissue growth can be described by observing temporal changes in ceU number, ie, hyperplasia, and ceU size, ie, hypertrophy. Growth also includes developmental aspects of function and metaboHsm of cells and tissues from conception to maturity. 

Matsumoto et al. developed an immunoassay for the determination of clenbuterol in bovine and equine tissues and in bovine milk. The LOD of clenbuterol in milk, muscle, liver, kidney, small intestine, and adipose tissues was 0.1 qgkg Bovine tissue samples fortified wifh 1 qg kg of clenbuterol had recoveries that varied from 75 to 96%, but recoveries from milk samples were 99%. The authors utilized this method to estimate the clenbuterol withdrawal periods for cattle and horses. Cattle were treated with a bolus dose of either 0.3 or 0.6 qg kg body weight, by intravenous injection, and three animals were slaughtered at days 1, 6, and 9. Tissue clenbuterol levels were detectable only on day 1. Clenbuterol in milk was not detectable after a 2.5-day withdrawal period. Liver contained the highest clenbuterol concentration of the tissues measured, but this group did not measure eye tissues. 

Organophosphate Ester Hydraulic Fluids. The measurement of organophosphate esters in fish and human adipose tissue has been used to assess environmental contamination in several studies (Mayer et al. 1981). The methods are able to detect concentrations of 0.1 mg/kg in fish and 2.5 pg/kg in human adipose... 

Olive oil was the original model lipid for partition studies, and was used by Overton in his pioneering research [518,524], It fell out of favor since the 1960s, over concerns about standardizing olive oil from different sources. At that time, octanol replaced olive oil as the standard for partition coefficient measurements. However, from time to time, literature articles on the use of olive oil appear. For example, Poulin et al. [264] were able to demonstrate that partition coefficients based on olive oil-water better predict the in vivo adipose-tissue distribution of drugs, compared to those from octanol-water. The correlation between in vivo log Kp (adipose tissue-plasma) and log (olive oil-water) was 0.98 (r2), compared to 0.11 (r2) in the case of octanol. Adipose tissue is white fat, composed mostly of triglycerides. The improved predictive performance of olive oil may be due to its triglyceride content. 

Lutein and zeaxanthin are the dominant carotenoids in nonretinal eye tissue, and lycopene and p-carotene have been found in the ciliary body, which after the retina and the retinal pigment epithelium (RPE) contains the highest quantity of carotenoids (Bernstein et al. 2001). The orbital adipose tissue also contains measurable quantities of lutein and p-carotene, and possibly other carotenoids as minor constituents (Sires et al. 2001). It is also interesting to note that lutein was recently identified in the vitreous body of human fetuses, 15-28 weeks old (Yakovleva et al. 2007). However, these results may have to be considered with caution, because the vitreous bodies were described as substantially being penetrated with hyaloid blood vessels, which could have contaminated the vitreous with blood. 

Liver histopathology and diarrhea recorded in all treated groups vs. none in controls. The 1000 mg/kg diet was the only ration to adversely affect the weight of all organs analyzed. After 5 weeks on PCP-free diet, residues were still measurable in adipose tissues of all treated birds (Stedman et al. 1980)... 

However, others maintain that adipose tissue is an important contributor to VD. Bjorkman showed that adipose and muscle tissue partitioning are the two tissues that yield the best predictions of VDSS and that such data obtained in other tissues did not offer more accuracy [27]. (Note that the tissue partitioning data used to predict human VDSS were from rat or rabbit ex vivo measurements.) The emphasis on both adipose and muscle was also advocated by Poulin and Thiel in their prediction method that uses solvent/water partition coefficients [28] (see below). 

Interpretation/results A GC-isotope ratio MS technique is used on known animal fats and the ancient samples. (In this technique, each peak eluting from the GC is combusted to C02 and its 12C-13C ratio is measured by a mass spectrometer [7].) The 13C ratio of the C-16 0 and C-18 0 fatty acids are plotted. The knowns are concentrated in specific areas on the plot, shown as ellipses in Fig. 21.16. The position of the cream sample points on this pattern recognition plot indicates that the fatty portion of the cream is from ruminant adipose tissue. 

Measurable levels of endrin have not been found in adipose tissue of the general population (Stanley 1986 Williams et al. 1984). Measurable tissue concentrations of endrin have been observed in cases of acute poisoning. The time of sample collection is critical as endrin residues in tissues decline rapidly after exposure has ceased. 

In a poisoning incident in Pakistan, patients with convulsions (sampling time not specified) had measurable blood levels of endrin ranging from 0.0003 to 0.254 ppm (Rowley et al. 1987). Tissues of a suicide victim contained the following concentrations of endrin 11 days after ingestion of 12 g of endrin in a formulation product 0.07 mg/L in blood, 89.5 mg/kg in adipose tissue, 0.87 mg/kg in heart, 0.89 mg/kg in brain, 0.55 mg/kg in kidneys, and 1.32 mg/kg in liver (Runhaar et al. 1985). 

The most commonly used methods for measuring mirex in blood, tissues (including adipose tissue), milk, and feces are gas chromatography (GC) or capillary GC combined with electron capture detection (ECD) or mass spectrometry (MS). Tables 6-1 and 6-2 summarize the applicable analytical methods for determining mirex and chlordecone, respectively, in biological fluids and tissues. 

Heptachlor epoxide was measured in a strip of skin, fat, and subcutaneous tissue from 68 children who died in the perinatal period and ranged from not detected (nondetectable) to 0.563 ppm (mean 0.173) (Zavon et al. 1969). In 10 other stillborn infants, heptachlor epoxide levels measured in various tissues were as follows brain (nondetectable), lung (0.17 0.07 ppm), adipose (0.32 0.10 ppm), spleen (0.35 0.08 ppm), liver (0.68 0.50 ppm), kidney (0.70 0.28 ppm), adrenal (0.73 0.27 ppm), and heart (0.80 0.30 ppm) (Curley et al. 1969). In another study, the following heptachlor epoxide levels were measured in extracted lipids from mothers and newborn infants maternal adipose tissue (0.28 0.31 ppm), maternal blood (0.28 0.46 ppm), uterine muscle (0.49 0.51 ppm), fetal blood (1.00 0.95 ppm), placenta (0.50 0.40 ppm), and amniotic fluid (0.67 1.16 ppm) (Polishuk et al. 1977a). These data provide evidence of transplacental transfer to the fetus. 

Unchanged heptachlor has not been detected in human adipose tissue however, heptachlor epoxide was measured in adipose tissue at levels ranging from 0.0001 to 1.12 ppm (Barquet et al. 1981 Burns 1974 Greer et al. 1980 Radomski et al. 1968 Wasserman et al. 1974) and in plasma at 0.0136 0.0057 ppm (Polishuk et al. 1977b). 

Detection of heptachlor epoxide may indicate either recent or past exposure. This compound has a long half-life, particularly in adipose tissue, because it is very lipophilic. Because of its highly lipophilic nature, heptachlor epoxide remains accumulated in adipose tissue for months to years. However, it is eventually mobilized into the serum and subsequently to the liver for further breakdown. Blood serum levels are often taken to indicate a recent exposure. Following long-term exposure, the level in the blood may be very low, but because of an equilibrium between fat and blood, it can be used to detect exposure to heptachlor epoxide. Thirty-five human adipose tissue samples were obtained during autopsy between 1987 and 1988 from residents of North Texas (Adeshina and Todd 1990). In 97% of these samples, there were measurable levels of heptachlor... 

Biomarkers of Exposure and Effect. Exposure to heptachlor and heptachlor epoxide is currently measured by determining the level of these chemicals in the blood or adipose tissue in living organisms (Curley et al. 1969 Klemmer et al. 1977 Radomski et al. 1968). This measure is specific for both heptachlor and heptachlor epoxide. Heptachlor epoxide is also a metabolite of chlordane, and thus its presence is not specific for exposure to heptachlor alone. However, in the absence of stable chlordane residues (e.g., nonachlor and oxychlordane), the heptachlor epoxide would most likely have been derived from heptachlor. Because heptachlor is believed to be converted rapidly in the body to heptachlor epoxide, it is impossible to determine whether the exposure was to one or the other of these two compounds. Heptachlor and heptachlor epoxide accumulate in adipose tissue and are released slowly over long periods of time. Therefore, it is not possible to accurately identify whether the exposure was recent or what the duration of exposure was. However, the ratio of heptachlor epoxide to heptachlor increases over time and therefore may be used as a biomarker of possible exposure to heptachlor. The sensitivity of the methods for identifying these compounds in human tissue appears to be only sufficient to measure background levels of heptachlor epoxide in the population. Additional biomarkers of exposure to heptachlor would be helpful at this time. 

Analytical methods exist for measuring heptachlor, heptachlor epoxide, and/or their metabolites in various tissues (including adipose tissue), blood, human milk, urine, and feces. The common method used is gas chromatography (GC) coupled with electron capture detection (ECD) followed by identification using GC/mass spectrometry (MS). Since evidence indicates that heptachlor is metabolized to heptachlor epoxide in mammals, exposure to heptachlor is usually measured by determining levels of heptachlor epoxide in biological media. A summary of the detection methods used for various biological media is presented in Table 6-1. 

There are three ways, notionaUy, of compartmentalising the body, depending on whether the mass of adipose tissue or triacylglycerol itself is being measured ... 

There is no gold standard for measuring the content of the triacylglycerol store, since adipose tissue is distributed in many different depots (see Appendix 2.4 for some of the methods that are available). 

Cariou R, Antignac JP, Zalko D, Berrebi A, Cravedi JP, Maume D, Marchand P, Monteau F, Riu A, Andre E, Le bizec B (2008) Exposure assessment of French women and their newborns to tetrabromobisphenol-A occurrence measurements in maternal adipose tissue, serum, breast milk and cord serum. Chemosphere 73 1036-1041... 

TABLE I. Chemical Residues Measured in Adipose Tissue... 

To measure average concentrations and prevalences of toxic substances in the adipose tissue of the general U.S. population To measure time trends of these concentrations ... 

In animal studies, the tissue distribution of " C-1,4-dichlorobenzene in female CFY rats was found to be similar following inhalation, oral, and subcutaneous exposure (Hawkins et al. 1980). The inhalation exposure regimen was 10 consecutive days of exposure to " C-1,4-dichlorobenzene at 1,000 ppm for 3 hours per day, and the highest concentrations of " C were measured in fat (up to 557 g/g via inhalation) and next highest levels in kidneys and liver. Concentrations in kidney and liver were about 5-10% of that found in adipose tissue, irrespective of the route of exposure. Distribution patterns for all routes were also similar to those observed by Kimura et al. (1979) using the oral route, as described below. 

Dichlorobenzene can be measured in blood (Bristol et al. 1982 Langhorst and Nestrick 1979 Pellizzari et al. 1985) or adipose tissue (Jan 1983 Pellizzari et al. 1985), and its metabolite, 2,5-dichloro-phenol, and/or its conjugates can be measured in urine (Langhorst and Nestriek 1979 Pagnotto and Walkley 1965) in order to confirm recent or prior exposure. 

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