Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Body Burden”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 109 records · Page 6Linked to original sources
PubMed1997

Lipid content and time-to-death-dependent lethal body burdens of naphthalene and 1,2,4-trichlorobenzene in fathead minnow (Pimephales promelas).

For naphthalene (NAPH) and 1,2,4-trichlorobenzene (TCBz), lethal body burdens (LBB) of 8 +/- 3.1 mmol/kg wet wt (ww) and 14 +/- 4.5 mmol/kg (ww), respectively, were determined in fathead minnow (Pimephales promelas). LBBs of both compounds were found to increase with increasing lipid content and time-to-death of fish within the same aquarium. The correlation with time-to-death suggests that besides lipid content at least one other factor causes intraspecies variation in LBBs. When intraspecies variation is excluded by comparing mean LBBs from different aquaria and exposure regimes, LBBs still vary with time-to-death. In contrast to the situation within one aquarium, between different aquaria and exposure regimes often a decrease in LBB with time-to-death is found. The present study and others indicate that LBBs can vary with time-to-death. Therefore, a time-independent LBB cannot be assumed.

Animals↗
PubMed2002

Prediction of the bioaccumulation factors and body burden of natural and synthetic estrogens in aquatic organisms in the river systems.

This study undertakes an initial prediction of the bioaccumulation factors and body burden of the steroid estrogens, estrone, estradiol, estriol and ethinylestradiol in a range of aquatic organisms (plankton, benthic and free-living invertebrates and fish) in river systems using a food-web model. These data are compared to that derived from less complex predictions based on octanol-water partition coefficient and molecular connectivity index. The model predicted that bioaccumulation of steroid estrogens occurred in all organisms, however, the values were small, and the maximum and minimum bioaccumulation factors in this study were found in the fish at the lowest trophic level with ethinylestradiol (332) and the fish at the highest trophic level with estriol (1.8), respectively. Moreover, the bioaccumulation factors were sensitive to the metabolic rates of the estrogens in the free living organisms, while the concentration of estrogens in sediment was a significant factor in determining these values in benthic invertebrates. Biomagnification contributed little to the overall bioaccumulation, but the importance increased in fish exposed to ethinylestradiol. The predicted bioaccumulation factors from the food web model were generally smaller than the calculated bioconcentration factors from the simpler octanol-water partition coefficient/molecular connectivity index based estimates. Compared to literature measured data, the predicted values for fish were approximately 1000 times less than the values observed in laboratory tests, while for invertebrates, the modeled values were less than two orders of magnitude below laboratory results. However, the model predicted a similar bioconcentration factor for plankton in relation to experimental data for Chlorella vulgaris for estrone and estriol.

Animals↗
PubMed1999

Long-term follow-up of the 137Cs body burden of individuals after the Chernobyl accident--a means for the determination of biological half-lives.

Since 1986, the year of the Chernobyl accident, 137Cs body burdens of members of a Bavarian reference group have been measured monthly. These time series were individually analyzed with respect to the long-term component T1 of the biological half-life of 137Cs, assuming a continuous 137Cs intake, which is based on reference data for the food consumption in the Federal Republic of Germany. In 13 individual cases, T1 was additionally deduced after single ingestion of 137Cs. The resulting T1 deduced from continuous and from single intake agreed within about 20%. Using the results of 64 cases, it is shown that there is a dependency of T1 with sex for adults. T1 for children and adults are also significantly different. When combining all data for children, adult females and adult males, significant correlations of T1 with age, 40K and body mass can be found. Since body mass, for example, is a parameter very simple to measure, the given correlations are useful for practical purposes.

Adolescent↗
PubMed1988

[A review of the literature on the concentration of arsenic, lead, cadmium and mercury in body fluids and tissues for the localization of normal values and the detection of body burden. 2. Cadmium].

The 2nd of 4 communications on metal concentrations in human body media deals with cadmium. Publications obtained from a comprehensive data bank search from January 1980 to April 1984 are listed in tables; study groups have been assigned to the following categories: normal; exposed; and exposed, exhibiting adverse health effects. Quality and strength of evidence of analytical procedures and reported data are discussed, particularly in light of adverse health effects. General methods and individual analytical procedures were presented in the 1st communication, a summary of mean exposure levels, critically elevated levels, and references will be published in the 4th communication.

Body Burden↗
PubMed1994

Effect of plumbing systems on lead content of drinking water and contribution to lead body burden.

Stable lead isotopes and lead contents in drinking water from a number of Australian cities have been measured to determine the contribution of drinking water to body burden. Lead contents are generally < 2 micrograms/l and thus contribute an insignificant amount to the lead budget in humans in Australia. First-flush and running water samples taken at intervals of up to 10 min show that equilibrium is reached within 1 min or approximately 10 l by volume. There is, however, large variability in both lead content and isotopic composition within the first minute which brings into question the reliability of the recommended sampling time of 30 s. Extremely large isotopic differences between individual dwellings within the one city and between dwellings and the storage tanks for the water supply are attributed to differences in lead residing in the plumbing within the dwellings, usually from lead solder in brass fittings. Isotopic analysis of solder and water from two dwellings confirm this relationship.

Australia↗
PubMed1995

Modeling of the toxicokinetics of polychlorinated dibenzo-p-dioxins and dibenzofurans in mammalians, including humans. I. Nonlinear distribution of PCDD/PCDF body burden between liver and adipose tissues.

Mixtures of polychlorinated dibenzo-p-dioxins and dibenzofurans, globally called PCDXs, are ubiquitously present in the environment. They accumulate in the human organism, especially through uptake from food. In view of their long residence time in the body and their potential adverse health effects for humans, it is therefore important to develop toxicokinetic models capable of predicting their distribution in human tissues. In the present study a physiologically based model which describes the distribution kinetics of PCDXs in various mammalian species is proposed. The approach is both theoretical and empirical. First, a plausible and general dynamical model that takes into account intercellular diffusion, PCDX-receptor and PCDX-protein binding, and PCDX-dependent enzyme induction in the liver is developed. Simplified formulas are proposed to predict the functional dependencies fh(Cb) and f(at)(Cb), which establish the fractions of the total PCDX body burden contained in liver and adipose tissues as a function of overall body concentration at any one moment. These formulas have fewer free parameters that can be determined for various species with the use of already available data. Model simulations are in agreement with published data on the distribution kinetics of PCDXs in rodents and monkeys and clinical data in humans. In rodents and monkeys as well as in humans, the respective relations fh(Cb) and f(at)(Cb) follow a similar nonlinear pattern. These varying distribution functions constitute the basis for a generalized toxicokinetic model of absorption and disposition described in a companion article (G. Carrier, R. C. Brunet, and J. Brodeur, 1995, Toxicol. Appl. Pharmacol. 131, 267-276).

Adipose Tissue↗
PubMed1997

Body burden measurements and models to assess inhalation exposure to methyl tertiary butyl ether (MTBE).

Biomarkers of methyl tertiary butyl either (MTBE) exposure and the partitioning of inhaled MTBE into the body were investigated in a human chamber study. Two subjects were exposed to an environmentally relevant nominal 5,011 micrograms/m3 (1.39 ppm) MTBE for 1 hour, followed by clean-air exposure for 7 hours. Breath and blood were simultaneously sampled, while total urine was collected at prescribed times before, during, and after the exposure. Mass-balance and toxicokinetic analyses were conducted based upon the time series measurement of multiple body-burden endpoints, including MTBE in alveolar breath, and MTBE and tertiary butyl alcohol (TBA) in venous blood and urine. The decay of MTBE in the blood was assessed by fitting the post-exposure data to a 2- or 3-exponential model that yielded residence times(tau) of 2-3 min, 15-50 min, and 3-13 h as measured by alveolar breath, and 5 min, 60 min, and 32 h as evaluated from venous blood measurements. Based on observations of lower than expected blood and breath MTBE during uptake and a decreasing blood-to-breath ratio during the post-exposure decay period, we hypothesize that the respiratory mucous membranes were serving as a reservoir for the retention of MTBE. The decay data suggest that 6-9% of the MTBE intake may be retained by this non-blood reservoir. The compartmental modeling was further used to estimate important parameters that define the uptake of inhaled MTBE. The first of these parameters is f, the fraction of C(air) exhaled at equilibrium, estimated as 0.60 and 0.46 for the female and male subject, respectively. The second parameter is the blood-to-breath partition coefficient (P) estimated as approximately 18. The product of these parameters provides an estimate of the blood concentration at equilibrium as 8-11 times the air concentration. Blood TBA lagged MTBE levels and decayed more slowly (tau = 1.5-3 h), providing a more stable indication of longer term integrated exposure. The concentration ranges of MTBE and TBA in urine were similar to that of the blood, ranging from 0.37 to 15 micrograms/L and 2 to 15 micrograms/L, respectively. In urine, MTBE and TBA by themselves bore little relationship to the exposure. However, the MTBE:TBA ratio followed the pattern of exposure, with peak values occurring at the end of the exposure (20- and 60-fold greater than pre-exposure values) before decaying back to pre-exposure levels by the end of the 7-h decay period. Urinary elimination accounted for a very small fraction of total MTBE elimination (< 1%).

Administration, Inhalation↗
PubMed1997

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) and congeners in infants. A toxicokinetic model of human lifetime body burden by TCDD with special emphasis on its uptake by nutrition.

Contents of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and of 16 further congeners--polychlorinated dibenzodioxins and dibenzofuranes (PCDD/PCDF)--were determined in lipids of adipose tissue and of livers of 3 stillborns and of 17 infants (0.43-44 weeks old) who died from sudden infant death syndrome. International toxic equivalents (I-TEq) calculated for the sum of TCDD together with all of the 16 congeners (1.55-29.63 ng/kg lipids of adipose tissue, n = 20; 2.05-57.73 ng/kg liver lipids, n = 19) were within the range of or lower than the values published for adults. TCDD concentrations in lipids of breast-fed infants were higher (0.38-4.1 ng/kg lipids of adipose tissue, n = 9; 0.49-3.9 ng/kg liver lipids, n = 8) compared to non breast-fed subjects (0.16-0.76 ng/kg lipids of adipose tissue, n = 8; 0.29-0.71 ng/kg liver lipids, n = 7). Neither I-TEq values nor TCDD concentrations exceeded values published for adults. Since even in stillborns PCDD/PCPF were found (I-TEq, 9.70-10.83 ng/kg lipids of adipose tissue, 6.17-8.83 ng/kg liver lipids; TCDD, 1.3-2.1 ng/kg lipids of adipose tissue, 0.76-1.5 ng/kg liver lipids; n = 3), transplacental exposure has to be deduced. All of the findings concerning TCDD concentrations in the organism become intelligible on the basis of a physiological toxicokinetic model which was developed to describe the body burden of TCDD for the entire human lifetime in dependence of TCDD uptake from contaminated nutrition. The model reflects sex and age dependent changes in the following parameters: body weight, volumes of liver, adipose and muscle tissue, food consumption, and excretion of faeces. TCDD is supposed to be taken up orally, to be distributed freely in lipids of the organism and to be eliminated unchanged by excretion in lipids of faeces as well as by metabolism in the liver. The model was used to predict the half-life of elimination of TCDD (4 months in newborns increasing to approximately 5 years in adults) and concentrations of this compound in lipids of adipose tissue, blood, liver and faeces at different ages. Furthermore, the influence of breast-feeding on the TCDD burden of a mother, her milk and her child was simulated. The model was validated by means of own data gained in adipose tissue and livers of infants and also using a series of values measured by other authors in mother's milk and in tissues and faeces of infants and adults. Predictions as well as experimental findings demonstrate a distinct increase in the TCDD body burden of breast-fed infants. Generally, it can be concluded for the excretion of unchanged, non-volatile, non protein bound highly lipophilic compounds that their half-life is short in infants (approximately 5 months) and increases to approximately 10 years reached between 40 and 60 years of age.

Adipose Tissue↗
PubMed2004

Simultaneous determination of the Cd and Zn total body burden of individual, nearly microscopic, nanoliter-volume aquatic organisms ( Hyalella azteca) by rhenium-cup in-torch vaporization (ITV) sample introduction and axially viewed ICP-AES.

The Cd and Zn total body burden of individual, up to 7-day-old aquatic organisms (Hyalella azteca benthic amphipod) with an average volume of approximately 100 nL was determined simultaneously by using rhenium-cup (Re-cup) in-torch vaporization (ITV) sample introduction and an axially viewed inductively coupled plasma atomic emission spectrometry (ICP-AES) system. The direct elemental analysis capabilities of this system (i.e., no sample digestion) reduced sample preparation time, eliminated contamination concerns from the digestion reagent and, owing to its detection limits (e.g., in the low pg range for Cd and Zn), vit enabled simultaneous determinations of Cd and Zn in individual, neonate and young juvenile specimens barely visible to the unaided eye (e.g., nearly microscopic). As for calibration, liquid standards and the standard additions method were tested. Both methods gave comparable results, thus indicating that in this case liquid standards can be employed for calibration, and in the process making use of the standard additions method unnecessary. Overall, the ITV-ICP-AES approach by-passed the time-consuming acid digestions, eliminated the potential for contamination from the digestion reagents, improved considerably the speed of acquisition of analytical information and enabled simultaneous determinations of two elements using individual biological specimens.

Amphipoda↗
PubMedDate not supplied

Indices of TCDD exposure and TCDD body burden in veterans of Operation Ranch Hand.

Using responses from a questionnaire detailing herbicide exposure during service in Vietnam and information on job classifications, we investigated the relationship between 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) body burden and self-reported exposure in enlisted members of Operation Ranch Hand, the United States Air Force herbicide spraying mission in Vietnam. We constructed three TCDD exposure indices from the questionnaire data: the number of days of skin exposure (DAYS), the percentage of skin area exposed (PCNT), and a combined index (SRI) which was the product of these and the concentration of TCDD in the herbicide. A fourth index (AFI) based on gallons of herbicide sprayed and the number of men on the job was also studied. The regression model most predictive of TCDD levels (R2 = 0.61) included job classification (divided into four categories), the number of days of skin exposure, percent body fat during the tour of duty, and relative change in body fat. A model with job classification alone had an R2 of 0.60. The four exposure indices were constructed to further explain TCDD exposure in the job classifications with the highest potential for exposure: Ranch Hand flight engineers and ground crew. In these two groups, days of skin exposure was the index most significantly associated with TCDD levels. Overall, the best index of exposure was the number of days of skin exposure to herbicide.

Adipose Tissue↗
PubMed2002

Antioxidant enzymes and peroxisome proliferation in relation to contaminant body burdens of PAHs and PCBs in bivalve molluscs, crabs and fish from the Urdaibai and Plentzia estuaries (Bay of Biscay).

With the aim of studying levels of antioxidant and peroxisomal enzymes and the structure of peroxisomes in relation to body burdens of polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs), mussels Mytilus galloprovincialis, oysters Crassostrea sp., crabs Carcinus maenas and mullets Mugil cephalus were sampled in two Basque estuaries (Bay of Biscay): Urdaibai (Laida, Txatxarramendi, Arteaga, and downstream a sewage treatment plant-STP) and Plentzia. In general, animals showed higher concentrations of contaminants in winter than in summer and no relevant differences were detected among locations. Conversely, antioxidant enzyme activities were higher in summer. Enzyme expression was studied in mullets using immunochemical methods. By immunoblotting season-dependent differences were detected for Mn-superoxide dismutase (Mn-SOD). As for the immunohistochemical staining, mullets sampled in summer in Plentzia showed significantly higher optical densities for acyl-CoA oxidase and lower for both Cu,Zn-SOD and Mn-SOD than those collected downstream a STP as well as higher catalase immunostaining than those collected in winter. Peroxisomal volume density (V(vp)) of mussels sampled in Laida and Txatxarramendi did not show seasonal variations, while for oysters collected in Laida and Arteaga V(vp) was higher in summer. Crab and mullet V(vp) were also higher in summer. In conclusion, the estuaries of Urdaibai and Plentzia can be considered as low to moderately polluted areas and levels of PAHs and PCBs do not show marked variations apart from seasonal variations. Animals can be adapted to low pollution conditions and, under these circumstances, seasonal factors might affect biomarker responses to a greater extent than pollution variations.

Adaptation, Physiological↗
PubMed1996

Analysis of body-burden measurements of 137Cs and 40K in a Japanese group over a period of 5 years following the Chernobyl accident.

A selected group of about 20 male researchers at the NIRS that reside in Chiba, Japan, was measured for total body content of radiocesium and 40K every 3 mo from February 1986 to May 1991. A whole-body counter at the NIRS was used to measure their radioactivity in a scanning mode of 5 cm min-1 in a shielded iron room with walls 20 cm in thickness. A maximum radiocesium level of 59 Bq was observed in May 1987. The annual change in the body burden decreased with an apparent half-time of 1.8 y after May 1987. The period of five years was sufficient to eliminate the effects of the accident in this group. Even in the most contaminated period, the dose from radiocesium was below 2 microSv y-1. The cumulative dose for 5 y was estimated to be 5.6 microSv, which is nearly equal to the total dose to the Japanese people caused by the artificial radionuclide fallout for the first year following the accident. It is much smaller than the committed dose of 82 microSv for internally deposited 137Cs resulting from nuclear explosions in 1961 and 1962 and the annual dose of 170 microSv from internal 40K. No detectable health risk was expected for the present group.

Body Burden↗
PubMed1984

Urinary metallothionein as an indicator of cadmium body burden and of cadmium-induced nephrotoxicity.

There is a need to identify specific biological indicator(s) of cadmium exposure so that the renal damage can be prevented. Towards this end, we have examined the usefulness of urinary metallothionein as an indicator of cadmium body burden. It is found that, in both animals and humans, urinary metallothionein level is related to the hepatic and renal cadmium burdens. Significant correlations are also found between the urinary metallothionein and urinary cadmium and beta 2-microglobulin. Furthermore, it is noted that cadmium-exposed individuals with renal dysfunction excrete significantly more metallothionein than those with normal renal function. Thus it appears that there is merit to include metallothionein among the clinical parameters monitored in cadmium-exposed individuals. More tests are needed to define a critical concentration of metallothionein in urine which is related to the onset of renal dysfunction.

Animals↗
PubMed1992

Trace metal accumulation by the shrew Sorex araneus. I. Total body burden, growth, and mortality.

A laboratory feeding trial is described in which a known trace metal accumulator, the shrew Sorex araneus, was presented with an artificial diet containing high levels of copper and cadmium. Methodological difficulties relating to feeding trials on first generation offspring of insectivorous small mammals caught in the wild are described. There was no relationship between copper or cadmium intake and mortality during the trials. Sex differences in growth were apparently not influenced by metal intake. At the end of the trials there was a significant negative correlation between body weight and total cadmium burden. Whole body concentrations and burdens of cadmium increased with estimated intake. There was a significant negative correlation between percentage of cadmium retained as body burden and estimated cadmium intake. There was no discernible relationship between copper burden and intake.

Animals↗
PubMed2003

[Low dose exposure to cadmium and its health effects. (4) Body burden, critical concentration and life expectancy].

As the last manuscript in our series of review articles on cadmium (Cd) and health effects, we reviewed research articles on epidemiologic and experimental studies on exposure levels of Cd in occupational and environmental settings in various countries, disposition and body burden of Cd, critical concentrations of Cd in the kidney of humans and animals with a focus on biomarkers for renal dysfunction, and life expectancy in Cd-polluted areas and reference areas. After this manuscript was compiled, cadmium levels in rice crops received significant attention, since the risk assessment of cadmium is now under review and discussion by the Joint Expert Committee of Food Additives and Contaminants organized by the Food Agricultural Organization and World Health Organization in 2003. We hope that the information compiled in this review may provide directions for future studies on the health risk assessment of Cd.

Animals↗
PubMed1998

Birth weight and sex of children and the correlation to the body burden of PCDDs/PCDFs and PCBs of the mother.

Polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and polychlorinated biphenyls (PCBs) were analyzed in 167 random human milk samples from urban and rural areas in Finland. Dietary habits and background information on each mother and child were gathered by questionnaire. Body mass indexes (BMI) before pregnancy and delivery in the rural area were 5-10% higher than in the urban area, but fat content of mother's milk was about 10% higher in the urban area. The mean weights of children (+/- standard deviation) were similar in the rural and urban areas among primiparae, 3,500 +/- 597 g and 3,505 +/- 454 g, respectively, although dioxin international toxic equivalents (I-TEQs) were significantly higher in the urban area. The mother's level of education did not affect the weight of the child, but concentrations of PCDDs/PCDFs (I-TEQ, 2,3,4,7,8-Cl5 dibenzofuran,1,2, 3,7,8-Cl5 dibenzodioxin) and PCBs [sum of PCBs (sumPCB), PCB-TEQ, and most PCB congeners] increased with advanced education. This is considered to be due to differences in the mother's consumption of fish. The birth weight, especially of boys, slightly decreased with increasing concentrations of I-TEQ, 2,3,4,7,8-Cl5 dibenzofuran, 1,2,3, 7,8-Cl5 dibenzodioxin, and 2,3,7,8-Cl4 dibenzodioxin; however, when the analysis was restricted to primiparae, there was no statistically significant correlation between birth weight and the concentrations of PCDDs/PCDFs. No correlation was found between the weight of the child and PCBs, PCB-TEQs, or individual PCB congeners in the whole material or among primiparae, or among boys or girls. The concentrations of PCDDs/PCDFs and PCBs inhuman milk were modeled for primiparae by weighing fish consumption, age of mother, milk fat content, and BMI before pregnancy. The linear regression resulted in values of R = 0.67 and 0.30 for the modeled dioxin I-TEQs in the urban and rural areas, respectively, and the corresponding values for sumPCBs of R = 0.60 and 0.11. The increase of PCDD/PCDF body burden was calculated to be on average 0.58 pg I-TEQ/g milk fat/year in the urban area and 0.39 pg I-TEQ/g milk fat/year in the rural area.

Adult↗