Mercury Accumulation In Tissues Research Articles

Dietary Selenomethionine Reduce Mercury Tissue Levels and Modulate Methylmercury Induced Proteomic and Transcriptomic Alterations in Hippocampi of Adolescent BALB/c Mice.

Methylmercury (MeHg) is a well-known environmental contaminant, particularly harmful to the developing brain. The main human dietary exposure to MeHg occurs through seafood consumption. However, seafood also contains several nutrients, including selenium, which has been shown to interact with MeHg and potentially ameliorate its toxicity. The aim of this study was to investigate the combined effects of selenium (as selenomethionine; SeMet) and MeHg on mercury accumulation in tissues and the effects concomitant dietary exposure of these compounds exert on the hippocampal proteome and transcriptome in mice. Adolescent male BALB/c mice were exposed to SeMet and two different doses of MeHg through their diet for 11 weeks. Organs, including the brain, were sampled for mercury analyses. Hippocampi were collected and analyzed using proteomics and transcriptomics followed by multi-omics bioinformatics data analysis. The dietary presence of SeMet reduced the amount of mercury in several organs, including the brain. Proteomic and RNA-seq analyses showed that both protein and RNA expression patterns were inversely regulated in mice receiving SeMet together with MeHg compared to MeHg alone. Several pathways, proteins and RNA transcripts involved in conditions such as immune responses and inflammation, oxidative stress, cell plasticity and Alzheimer’s disease were affected inversely by SeMet and MeHg, indicating that SeMet can ameliorate several toxic effects of MeHg in mice.

Electro-magnetic Field Radiation of Mobile Phones As A Cause of Increased Release of Mercury from Amalgam Fillings and Risk of Harmful Effects on Health

The aim of the research is to determine whether there was synergism between mobile phone exposure and higher release and accumulation of mercury in tissues of the individuals with amalgam fillings. For this purpose, the computer electro-magnetic simulation and the Bi-Digital O-Ring Test (BDORT) method were used. For the electro-magnetic simulation, the FIT method (Finite Integration technique - numerical simulation method for calculation elelctromagnentic fields in space, expecialy in body) was used and the results of the electric field and Specific absorption rate (SAR) in the tooth model with and without amalgam fillings were obtained. Specific absorption rate is a measure of the rate at which energy is absorbed by the human body when exposed to a radio frequency (RF) electromagnetic field. It is dose for absorbed electromagnetic radiation which is dependent on frequency and can be associated with the adverse effect of tissue heating. Standards indicate SAR values that should not be exceeded. The numerical result of absorption electro-magnetic energy shows increased value of the electric field, magnetic field, induced currents and SAR in teeth with fillings. These results indicated the possible explanation of the increased release mechanism of the mercury (Hg) when using mobile phones. The Bi-Digital O-Ring Test method tested the levels of mercury in the body, liver, and urine in a group of examinees who had amalgam fillings and used cell phones. By using indirect BDORT we examined groups of examinees 10 with and 10 examinees without amalgam fillings. By using BDORT we measaured level ofHg in the body and urin samples in all examinees before exposure to electromagnetic fields (EMFs) of mobile phone and after 15 minutes of exposure of mobile phone EMF. The results showed significantly higher level of Hg in urin after exposure of EMF of mobile phone, only in a group of examinees with amalgam fillings. The results showed significant matches with some published papers by other researchers. These effects might cause potential organism disorders and represent secondary harmful effects of electro-magnetic radiation on the health of individuals. This approach throws a new light in clarifying the interplay of cellular electro-magnetic radiation and increased the release of mercury from the amalgam fillings. Increased toxic effects are imposed by themselves as possible.

Patterns of Mercury Accumulation in Tissues of Western Sandpipers (Calidris mauri ) Wintering on the Coast of Sinaloa, Mexico

Mercury concentration was quantified in liver, muscle, and primary feathers of pooled samples of Western Sandpiper (Calidris mauri) collected in December-January 2010 (wintering) and March-April 2011 (premigration) in Ensenada Pabellones and Bahia Santa Maria, Sinaloa, Mexico, to test for differences between sites, stages, tissues, and age-sex groups. During the winter, mercury concentrations were greater in individuals from Ensenada Pabellones than those from Bahia Santa Maria (0.81 ± 0.05 vs. 0.57 ± 0.05 mg/kg dry weight, respectively), and greater in liver than in muscle (0.89 ± 0.05 vs. 0.49 ± 0.05mg/kg dry weight, respectively). In the comparison between the stages, wintering birds had greater concentrations of mercury than those of premigration period (0.62 ± 0.05 vs. 0.48 ± 0.05 mg/kg dry weight, respectively). These mercury concentrations were lower than those found in other wintering sites in North America (mean = 4.4 mg/kg dry weight). Although these concentrations suggest that Western Sandpipers wintering on the coast of Sinaloa, Mexico, were being exposed to low mercury concentrations and had not accumulated mercury, it appears that mercury in their tissues decreased during the nonbreeding season. However, these conclusions are based on low numbers in some categories and require further work with individual, rather than pooled, samples.

Form of Dietary Methylmercury does not Affect Total Mercury Accumulation in the Tissues of Zebra Finch.

Exposure to mercury in humans, other mammals, and birds is primarily dietary, with mercury in the methylated form and bound to cysteine in the tissues of prey items. Yet dosing studies are generally carried out using methylmercury chloride. Here we tested whether the accumulation of total mercury in zebra finch blood, egg, muscle, liver, kidney or brain differed depending on whether dietary mercury was complexed with chloride or cysteine. We found no effect of form of mercury on tissue accumulation. Some previous studies have found lower accumulation of mercury in tissues of animals fed complexed mercury. Much remains to be understood about what happens to ingested mercury once it enters the intestines, but our results suggest that dietary studies using methylmercury chloride in birds will produce similar tissue accumulation levels to those using methylmercury cysteine.

Dimercaptopropane Sulfonate Chelation Affects In Vivo Hg and MeHg Distribution in Tissues and Urine of Prairie Voles (Microtus ochrogaster)

Methyl mercury cation (MeHg(+)) and divalent mercury (Hg(2+)) were quantified in urine, liver, kidney, and brain of prairie voles (Microtus ochrogaster) during a 12week exposure to aqueous MeHg(+) at concentrations of 10, 100, and 1000ng MeHg(+)/mL. Aqueous MeHg(+) exposures increased mercury accumulation in tissues of voles from each exposure group. Accumulation was greater within the higher two exposure groups. Similar [Hg(2+)] and [MeHg(+)] were determined within a given organ type before and after 2,3-dimercapto-1-propane sulfonate (DMPS) chelation. Similar correlations were seen for Hg(2+) and MeHg(+) concentrations in pre and post chelation urine. Post chelation urine more reliably predicted mercury species concentrations in tissues than did urine collected before chelation. These data demonstrate the utility of DMPS in noninvasive assessment of wildlife exposure to mercury, which may have utility in evaluating meta-population level exposure to hazardous wastes.

Distribution and accumulation of mercury in tissues of captive‐reared common loon (Gavia immer) chicks

We determined the distribution and accumulation of Hg in tissues of common loon (Gavia immer) chicks maintained for up to 15 weeks on either a control diet with no added methylmercury chloride (MeHgCl) or one containing either 0.4 or 1.2 microg Hg (as MeHgCl)/g wet-weight food. Total Hg and MeHg tissue concentrations were strongly positively correlated (r2 > 0.95) with the amount of Hg delivered to individual chicks throughout the course of the experiment. The pattern of differential Hg concentration in internal tissues was consistent within each treatment: Liver > kidney > muscle > carcass > brain. Feather Hg concentrations were consistently higher than those of internal tissues and represented an important route of Hg elimination. Feather mass accounted for 4.3% +/- 0.1% (average +/- standard error) of body mass, yet 27.3% +/- 2.6% of total Hg intake was excreted into feathers. Our calculations indicate that 26.7% +/- 4.9% of ingested Hg was not accounted for and, thus, either was never absorbed or was absorbed and subsequently eliminated in feces. With the additional excretion into feathers, 54% of ingested Hg was excreted. Demethylation was evident in the liver at all treatment levels and in the kidneys of chicks dosed at 1.2 microg Hg/g. Mercury concentrations were strongly positively correlated (r2 > or = 0.95) among internal tissues and with blood Hg concentration. Mercury concentrations of secondary feathers were moderately correlated (r2 = 0.82-0.93) with internal tissues. We supply regression models that may be used to provide perspective and a useful means of interpreting the variety of measures of Hg exposure reported in the literature.

Antioxidant responses and bioaccumulation in Ictalurus melas under mercury exposure

Laboratory experiment was carried out to determine mercury accumulation in tissues (gills, kidneys, liver, and muscle) and biochemical responses in the liver of freshwater teleost Ictalurus melas. Catfish were subjected to different concentrations of Hg 2+ (35, 70, and 140 μg/L) for 10 days. The chemical analyses showed higher mercury concentrations for all treatments in gills and kidneys followed by liver and muscle. At the lowest mercury concentration a decrease in glutathione (GSH) content and an increase of GSH peroxidase Se-dependent and glyoxalase II enzymes were observed. An increasing trend was observed also for GSH- S-transferase and glyoxalase I, while GSH peroxidase Se-independent enzyme and GSH reductase showed no significant variation in activities. The increase in the enzymes activities of catfish, involved in the inactivation of reactive molecules formed during oxidative stress, could provide an additional protection against the oxidative damage induced by mercury.

Bioaccumulation and distribution of mercury in the hard clam, Meretrix lusoria (Bivalvia:Veneidae)

1. Total mercury concentration in whole soft parts of the hard clam, Meretrix lusoria, increased significantly with increasing exposure concentrations. It reached 4.247-7.084 and 9.956-13.643 micrograms T-Hg/g dry weight in 5 and 50 micrograms/l Hg mercury solution, respectively, against a background level of 1.824-0.577 micrograms T-Hg/g dry weight. 2. Bioconcentration factor was 4-6 times higher in 5 micrograms/l Hg than that of 50 micrograms/l Hg. An estimated biological half-life of 20.2 and 18.4 days in 5 and 50 micrograms/l Hg, respectively, were also obtained after 14 days uptake. 3. Accumulation of mercury in tissues of the clams was greater in the gills and viscera than in the mantle, adductor, foot, or hemolymph. 4. The amount of mercury present in the gills is related to be a linear relationship with the mercury content of viscera.

Mercury levels in the plumage of red-billed gulls Larus novaehollandiae scopulinus of known sex and age.

Samples of 4-8 small body feathers were taken from 27 chicks and 35 adult red-billed gulls caught at their nests on the Kaikoura Peninsula, New Zealand, in December 1988. The adults had been ringed as chicks and were of known ages from 2 to 15 years old. Analysis of total mercury in the feather samples showed that levels were independent of sex and age in adults. Mean fresh weight concentration in adult body feathers was 2.4 microg g(-1). The lack of age accumulation of mercury in gull feathers contrasts with the well known age related accumulation of mercury in tissues of fish and marine mammals, but agrees with predictions of recent studies on mercury dynamics in birds. Mercury levels in chick feathers were about 80% of levels in adult feathers.

Species difference between rat and hamster in tissue accumulation of mercury after administration of methylmercury.

The accumulation of mercury in tissues of the rat and hamster was determined after the administration of a single dose of 203Hg-methylmercury chloride (10 mg/kg body weight). On day 2, the mercury contents of hamster tissues were higher than those of rat tissues, except for red blood cells, in which the mercury content was about 6-fold higher in the rat than in the hamster. After that time, the mercury content of hamster tissues decreased rather steeply and on day 16 it had reached 14-25% in nervous tissues and 7-15% in other tissues, of the levels on day 2. In the rat, on the other hand, the mercury content of nervous tissues on day 16 was higher than that on day 2 (106-220%), except for dorsal roots and dorsal root ganglia, which showed slight decreases (75-94% of the levels on day 2). In non-neural tissues, the decreases up to day 16 were also small (71-92% of the levels on day 2). Thus, both the uptake and elimination of mercury seem to be more rapid in the tissues of hamster compared with those of the rat. Similar trends of mercury accumulation and elimination were observed when animals received multiple injections of methylmercury that induced acute methylmercury intoxication. Significant biotransformation of the injected methylmercury to inorganic mercury was detected in the liver, kidney and spleen of both animal species.(ABSTRACT TRUNCATED AT 250 WORDS)

Use of whale meal and whale solubles as dietary protein for growing pigs and their effects on the accumulation of mercury in tissues

The effects of supplementing the protein from wheat in diets for growing pigs with either whale meal, whale solubles, fish meal, meat and bone meal or with combinations of whale meal or whale solubles with fish meal or meat and bone meal, were studied in two experiments. The mercury concentration in the muscle and liver of pigs fed the whale products was also studied. Pigs fed diets containing whale solubles as the only protein concentrate, grew more slowly, required more food per unit of liveweight gain and tended to have less lean in their hams than pigs fed diets containing concentrate protein from whale meal and/or fish meal, whale meal and meat and bone meal, or whale solubles and fish meal. The differences in pig performance between diets containing whale meal or meat and bone meal were not significant. Whale meal and whale solubles contained 10.5 and 2.5 p.p.m. of mercury, respectively, and the concentration of mercury in the diet was correlated to the mercury concentration in the tissues of pigs fed the diet. The muscle and liver of pigs fed with protein from whale meal had higher concentrations of mercury than those of pigs fed diets with equal amounts of protein from whale solubles. All the pigs fed whale products in this experiment had a concentration of mercury in their tissues greater than the health standard for human feedstuffs.

Accumulation of mercury in tissues of cattle, sheep, and chickens given the mercurial fungicide, Panogen 15, orally.

Accumulation of mercury in tissues of cattle, sheep, and chickens given the mercurial fungicide, Panogen 15, orally.