Feces recovery

P-isomer) to milk sheep resulted in recovery of approximately 50% of the radiolabel in the feces,... 

Radioactivity Analysis. Samples of urine, feces, and tissues were combusted to COo and analyzed for radioactivity (5). By using this method the recovery of radioactivity from samples spiked with C was 95 dt 5%. To determine the radioactivity expired as CO2, 5-ml aliquots of the solution used to trap the CO2 were added to 15 ml of a scintillation counting solution containing 4 grams 2,5-diphenyloxazole (PPO) and 0.1 grams l,4-bis-2(5-phenyloxazolyl)-benzene (POPOP) per liter of 1 1 toluene 2-methoxyethanol. Samples were counted for radioactivity in a Nuclear Chicago Mark II liquid scintillation counter. Counting eflSciency was corrected by the internal standard technique. 

It is normally found in Italy and some European countries. The natural reservoir is pigs. Virus may continue to be shed in the feces of pigs for up to 3 months after full recovery. Resistant to fermentation and smoking processes. May remain in hams for 6 months, dried sausages for more than a year, and in processed intestinal casings for more than 2 years. 

Following dose administration, rats are placed in individual cages. The urine and feces that collect in containers are removed at predetermined intervals. The volume of urine and the weight of feces are measured. After the final collection, the cage is rinsed, normally with ethanol or water, to assure complete recovery of excreta. If the rats are also used for serial blood sampling, it is important that bleeding be performed inside the cage to avoid possible loss of urine or feces. 

Expired air. For 14C-labeled chemicals, the tracer carbon may be incorporated in vivo into carbon dioxide, a possible metabolic product. Therefore, when the position of the radiolabel indicates the potential for biological instability, a pilot study to collect expired air and monitor its radioactivity content should be conducted prior to initiating a full-scale study. Expired air studies should also be performed in situations where the radiolabel has been postulated to be stable but analyses of urine and feces from the toxicokinetic study fail to yield complete recovery (mass balance) of the dose. 

Recoveries (% of dose) were fish 80.6, water 12.2, and feces 1.0. Sample size 3 in all cases. Values are mean S.E. 

Feces from injected (7.9 mg/kg) male rats were collected for one week and extracted with acetone yielding about 50% of the dose. Fish were treated with 5 ppb of the compound in water for 48 hr and then held in clean water for 11 days at the end of which they were extracted whole with organic solvents. Recovery of the compound applied to fish was 74.3%. Chromatographs (0.25 mm Silica gel GF-254) were developed with heptane twice. The figure shows relative abundance of metabolites in the two species. PC is photo-cis-chlordane. 

No studies were located in humans regarding the distribution of 1,2-dibromoethane after oral exposure. In humans intentionally ingesting 1,2-dibromoethane, kidney lesions and centrilobular necrosis of the liver were found (Olmstead 1960 Saraswat et al. 1986). This is indirect evidence of distribution of 1,2-dibromoethane. The tissue distribution of 1,2-dibromoethane has been studied in rats following exposure by the oral route. Although retention was limited, the kidneys, liver, and spleen appear to retain the highest amounts of the administered dose (Plotnick et al. 1979) as illustrated in Table 2-4. Rats received an oral dose of 15 mg/kg/day of labeled 1,2-dibromoethane in corn oil. Twenty-four hours later 3% of radioactivity was detected in fat, brain, kidney, liver, spleen, testes, blood, and plasma, 72.38% in the urine, and 1.65% in the feces (Plotnick et al. 1979). By 48 hours after administration, 73% of the radiolabeled dose was accounted for in the urine, 1.1% in the liver, and 2.4% in the feces. Total recovery was 77.8% of the administered radioactivity. 

Excretion of radioactivity in mice and rats was monitored for 48 hours following exposure to " C-labeled chloroform (Corley et al. 1990). In general, 92-99% of the total radioactivity was recovered in mice, and 58-98% was recovered in rats percentage of recovery decreased with increasing exposure. With increasing concentration, mice exhaled 80-85% of the total radioactivity recovered as " C-labeled carbon dioxide, 0.4-8% as " C-labeled chloroform, and 8-11 and 0.6-1.4% as urinary and fecal metabolites, respectively. Rats exhaled 48-85% of the total radioactivity as " C-labeled carbon dioxide, 2-42% as " C-labeled chloroform, and 8-11 and 0.1-0.6% in the urine and feces, respectively. A 4-fold increase in exposure concentration was followed by a 50- and 20-fold increase in the amount of exhaled, unmetabolized chloroform in mice and rats, respectively. 

In another study in which male and female Fisher 344 rats were administered a single dose of 900 mg/kg/day 1,4-dichlorobenzene by gavage in com oil and sacrificed at 72 hours, the percentage of the dose found in tissues and excreta from males was tissues (all organs pooled), 0.05% fat, 0.1% blood, 0.04% feces, 3.6% and urine, 41.3%. Thus, more than half (55%) of the dose was probably exhaled 60% was not accounted for. In females recovery of radioactivity was tissue, 0.04% fat, 0.1% blood, 0.03% feces, 2.5% and urine, 37.8%. In the tissues examined, the radioactivity bound to protein was below the detection limit (Klos and Dekant 1994). Charbonneau et al. (1987) reported that 49.8% of... 

Excretion - 84% of total radioactivity is excreted in urine and approximately 4% in feces, resulting in a mean recovery of 88%. Less than 0.1 % of the dose was excreted in urine and feces as the parent compound. Elimination was essentially complete by 96 hours postdose. 

Metabolism/Excretion - Emtricitabine is not an inhibitor of human CYP450 enzymes. Following administration of emtricitabine, complete recovery of the dose was achieved in urine (approximately 86%) and feces (approximately 14%). The plasma emtricitabine half-life is approximately 10 hours. The renal... 

Metabolism/Excretion - Negligible amount of drug is excreted as mycophenolic acid (less than 1% of dose) in the urine. Oral administration resulted in complete recovery of the administered dose 93% was recovered in the urine and 6% recovered in feces. Mean apparent half-life of mycophenolic acid is about 17.9 hours following oral administration. 

DMHP in plasma appears to have a half-life of 20 h in both rat and rabbit the half-life of total radioactivity ([ C]DMHP plus C-labeled metabolites) in the slower phase of elimination was approximately 24 h. In the rat, 70% of the total radioactivity of the intravenous dose was recovered in urine and feces during 72 h 4% was excreted in urine and 66% was found in feces. A 7-d collection of urine and feces of rabbits given [1 C]DMHP resulted in recovery of 87% of the total radioactivity—24% in urine and 63% in feces. In mouse brain,29 the half-life of [ H]A-9-DMHP appeared to be about 20 h, whereas 11-hydroxy-DMHP and the "polar metabolite" seem to have (by extrapolation) half-lives in excess of 48 h. All three values were calculated on the basis of the slower phase of elimination. 

Biological Samples. There were three types of biological samples obtained from workers at the plant urine, whole blood, and feces. All urine and blood samples were internally "spiked" at the factory with 1 yg/mL of a nitrosopiperidine (NPiP) standard. NPiP was used for spiking because it has a similar stability and recovery characteristic to nitrosomorpholine, and to provide a means of gauging the accuracy of the analytical methods. Due to the inability to perform homogeneous mixing on-site, the feces samples were not spiked until they were thawed upon return to the laboratory. Ethyl acetate extracts of urine samples were examined for the presence of N-nitrosodiethanolamine (NDEIA), a metabolite of NMOR, by HPLC-TEA. All samples were immediately frozen at the plant (-80°C) and kept at this temperature until analysis. 

In an acute feeding study in rats fed analytical-grade decaBDE for 12 days and " C-decaBDE on day 8, recovery of radioactivity in the feces on days 9-12 ranged from 91.3 to 101% of the amount ingested (El Dareeretal. 1987). 

In vivo tests require animal feeding studies, and all of the factors outlined under PER apply. In addition, for digestibility calculations, accurate measurement of feed consumed, complete recovery of feces (devoid of feed), possibly urine, and calculation of body composition are required. These are not the most pleasant experimental protocols to conduct, but have to be done carefully and correctly if meaningful results are to be obtained. 

Toxicokinetics studies are designed to measure the amount and rate of the absorption, distribution, metabolism, and excretion of a xenobiotic. These data are used to construct predictive mathematical models so that the distribution and excretion of other doses can be simulated. Such studies are carried out using radiolabeled compounds to facilitate measurement and total recovery of the administered dose. This can be done entirely in vivo by measuring levels in blood, expired air, feces, and urine these procedures can be done relatively noninvasively and continuously in the same animal. Tissue levels can be measured by sequential killing and analysis of organ levels. It is important to measure not only the compound administered but also its metabolites, because simple radioactivity counting does not differentiate among them. 

Adequate digestion methods are important in the determination of all metals, including aluminum. Que Hee and Boyle (1988) showed that Parr bomb digestions were always superior to hot plate digestions for many elements, including aluminum, in feces, liver, and testes. Microwaving in closed vessels produced lower aluminum recoveries in liver than Parr bomb digestions. The Parr bomb values for citrus leaves were within 5% of the NBS certified values. 

Metabolic Transit of Lysinoalanine. Urinary and Fecal Excretion of Protein-Bound Lysinoalanine (113). Three different alkali-treated proteins (lactalbumin, fish protein isolate, and soya protein isolate) containing, respectively, 1.79, 0.38, and 0.14 g of lysinoalanine/16 g nitrogen were given to rats and the urines and feces were collected. Lysinoalanine was measured before and after acid hydrolysis. The fecal excretion varied from 33 to 51% of the total ingested lysinoalanine and the urinary excretion varied from 10 to 25%. The higher level of lysinoalanine found after acid hydrolysis indicates that a certain quantity is excreted in the urines as combined lysinoalanine (see Table VII). The total recovery was inferior to the ingested quantity (50 to 71%) indicating that the molecule is transformed or retained in the body of the rat. 

Alkali- Urines Feces Total Recovery After... 

Screening methods are available for analysis of benzene in feces and urine (Ghoos et al. 1994) and body fluids (Schuberth 1994). Both employ analysis by capillary GC with an ion trap detector (ITD). Benzene in urine has been determined by trapping benzene stripped from the urine on a Carbotrap tube, followed by thermal desorption GC/flame ionization detection (FID). The detection limit is 50 ng/L and the average recovery is approximately 82% (Ghittori et al. 1993). Benzene in urine has also been determined using headspace analysis with capillary GC/photoionization detection (PID). The detection limit is 40 ng/L (Kok and Ong 1994). 

A few studies have evaluated the survival rate of freeze-dried S. cerevisiae spp. in human volunteers following their oral administration. Nevertheless, comparison between in vitro results in the TIM and these in vivo data is hampered by the fact that yeast survival had been evaluated only in feces (and not at the end of the ileum) after a single or multiple oral administration of the microorganisms. Klein et al. [49] found a fecal recovery of 0.12 0.04% (n = 8) after a single dose of 1 g of S. boulardii [10104 colony-forming units (CFU)] to healthy volunteers, and Blehaut et al. [50] measured a steady-state fecal recovery of 0.36 + 0.31% (n = 8) after oral administra-... 

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