Trimetazidine Protects from Mercury-Induced Kidney Injury

INTRODUCTION

The presence of mercury in the environment is a worldwide concern. Inorganic mercury is present in industrial materials, is employed in medical devices, is widely used in batteries, is a component of fluorescent light bulbs, and it has been associated with human poisoning in gold mining areas. The nephrotoxicity induced by inorganic mercury is a relevant health problem mainly in developing countries. The primary mechanism of mercury toxicity is oxidative stress. Trimetazidine (TMZ) is an anti-ischemic drug, which inhibits cellular oxidative stress, eliminates oxygen-free radicals, and improves lipid metabolism. The aim of this study was to evaluate whether the administration of TMZ protects against mercuric chloride (HgCl2) kidney damage.

METHODS

Adult male Wistar rats received only HgCl2 (4 mg/kg bw, sc) (Hg group, n = 5) or TMZ (3 mg/kg bw, ip) 30 min before HgCl2 administration (4 mg/kg bw, sc) (TMZHg group, n = 7). Simultaneously, a control group of rats (n = 4) was studied. After 4 days of HgCl2 injection, urinary flow, urea and creatinine (Cr) plasma levels, Cr clearance, urinary glucose, and sodium-dicarboxylate cotransporter 1 (NaDC1) in urine were determined. Lipid peroxidation (MDA) and glutathione (GSH) levels were measured in kidney homogenates.

RESULTS

Rats only treated with HgCl2 showed an increase in urea and Cr plasma levels, urinary flow, fractional excretion of water, glucosuria, and NaDC1 urinary excretion as compared with the control group and a decrease in Cr clearance. TMZHg group showed a decrease in urea and Cr plasma levels, urinary flow, fractional excretion of water, glucosuria, NaDC1 urinary excretion, and an increase in Cr clearance when compared to the Hg group. Moreover, MDA and GSH levels observed in Hg groups were decreased and increased, respectively, by TMZ pretreatment.

CONCLUSION

TMZ exerted a renoprotective action against HgCl2-induced renal injury, which might be mediated by the reduction of oxidative stress. Considering the absence of toxicity of TMZ, its clinical application against oxidative damage due to HgCl2-induced renal injury should be considered. The fact that TMZ is commercially available should simplify and accelerate the translation of the present data "from bench to bedside." In this context, TMZ become an interesting new example of drug repurposing.

Selenium modulated gut flora and promoted decomposition of methylmercury in methylmercury-poisoned rats

INTRODUCTION

Selenium plays important roles in antagonizing the toxicity of methylmercury. The underlying mechanism for the antagonism between Se and MeHg is still not fully understood.

OBJECTIVE

The role of gut flora against the toxicity of environmental contaminants is receiving more and more attention. The objective of this study was to investigate the role of Se against MeHg-poisoning in the modulation of gut flora and the decomposition of MeHg.

METHODS

MeHg-poisoned rats were treated with sodium selenite every other day for 90 days. Fecal samples were collected on Day 8, 30, 60 and 90. Gut flora in feces was determined using 16S rRNA gene profiling, and the concentrations of Se and total mercury (THg) were measured by ICP-MS, and the concentration of MeHg was measured by CVAFS.

RESULTS

Gut flora at both the ranks of phylum and genus in the MeHg-poisoned rats after Se treatment was modulated towards that in the control group, suggesting the restoration of the profile of gut flora. Increased THg was found in fecal samples after Se treatment on day 30. The percentage of MeHg (of total mercury) in the MeHg-poisoned group was in the range of 81-105% while it was 65-84% in the Se treatment group on different days, suggesting the increased decomposition of MeHg in MeHg-poisoned rats after Se treatment.

CONCLUSIONS

This study suggests that MeHg poisoning damaged the abundance of gut flora and decreased their capacity for the decomposition of MeHg. After Se treatment, the abundance of gut flora was partially restored and the decomposition and excretion of MeHg was enhanced. These findings suggest that the modulation of gut flora may be one way to promote the health status in MeHg-poisoned rats and possibly in human beings.

Mercury Spill Responses - Five States, 2012-2015

Despite measures to educate the public about the dangers of elemental mercury, spills continue to occur in homes, schools, health care facilities, and other settings, endangering the public's health and requiring costly cleanup. Mercury is most efficiently absorbed by the lungs, and exposure to high levels of mercury vapor after a release can cause cough, sore throat, shortness of breath, nausea, vomiting, diarrhea, headaches, and visual disturbances (1). Children and fetuses are most susceptible to the adverse effects of mercury vapor exposure. Because their organ systems are still developing, children have increased respiratory rates, and they are closer to the ground where mercury vapors are most highly concentrated (2). To summarize key features of recent mercury spills and lessons learned, five state health departments involved in the cleanup (Iowa, Michigan, Missouri, North Carolina, and Wisconsin) compiled data from various sources on nonthermometer mercury spills from 2012 to 2015. The most common sites of contamination were residences, schools and school buses, health care facilities, and commercial and industrial facilities. Children aged <18 years were present in about one third of the spills, with approximately one in seven incidents resulting in symptoms consistent with acute mercury exposure. To protect the public's health after a mercury spill, it is important that local, state, and federal agencies communicate and coordinate effectively to ensure a quick response, and to minimize the spread of contamination. To reduce the number of mercury spills that occur in the United States, public health officials should increase awareness about exchange programs for mercury-containing items and educate school and health care workers about sources of mercury and how to dispose of them properly.

[The approach to the regulation of mercury according to the content of its termoforms in soils and bed loads]

The article contains the results of the ecological and hygienic diagnostics of conditions of lands of areas of different sizes and varying degrees of urbanization, located in different agro-climatic conditions of European Russia (the southern Astrakhan region, he city of Moscow). Assessments of the state of territories use a new approach to rationing of Hg according to quantitative ratios of the content of its thermoforms in soils, grounds and alluvium (in litho substrate). The method of diagnostics is based on known properties of Hg forms: their geochemical activity (migration mobility) and toxicity decline along with the increment of the Hg temperature threshold of the release in the process of continuous warming up of the litho substrate sample (up to 1100°C). Thermoforms are not tied to specific minerals or chemicals and are conditionally designated as FR (Free: <180°C), CL (Chloride: 180-250°C), FS and CS (physically and chemically sorbed: 250-400°C), SU (Sulfide: 400-500°C) IS (isomorphic: >500°C) Hg forms. Among forms, also conditionally according to complexes of low, medium and high temperature variations(FR + CL, FS + CS and SU + IZ, respectively, there are selected groups of «mobile», «sustainable» and «inert» forms. For technogenic Hg there is characterized the predominance in the sample of «mobile» and to lesser extent degree - «stable» thermoforms. The more intensive this predominance is, the higher is environmental hazard. The natural accumulation is diagnosed by the presence and prevalence of the sum of moderate - and high-temperature inert forms of Hg. According to the ratios of Hg content, its forms and groups, as well as the density of correlationships between them, 6 indices of the conditions of soils and alluvium were developed by ourselves.Main coefficients out of indices on informativeness of results of diagnostics are the following factors: Endogenous input, Geochemical activity and Hg mobility. With regard to the combination of variability in indices, the total amount of Hg, the genesis and intensity of its accumulation (natural or anthropogenic), there were also developed ranking scales of the ecological and hygienic condition of the land areas and surface water bodies. As a result, on the base of such approach to the regulation of Hg the information value of assessments of mercury contamination of land significantly increased. At the objects of assessments there were identified following areas: foci of the manifestation of Hg hypolimnetic emanations on the landscape surface - dispersion halos in the areas of the Earth crust fracture (the dome of the Astrakhan gas condensate field); environmentally dangerous (sometimes even at a low total content of Hg) parts of cities, towns, their districts, as well as beds of watercourses and water reservoirs bottom (the Volga river valley and delta, the Lefortovo quarter in Moscow). There was also diagnosed the threshold of the background distribution of gross Hg content detected = 0.2-0.3 mg/kg. Its magnitude is consistent with domestic and abroad safe levels of Hg accumulation in soils = 0.3-0.4 mg/kg. The approach provides the differentiation of the environmental hazard lands. Technology of the approach can be used in the development of normative Document for the diagnosis of environmental and sanitary condition of territories in the system of Classifications of hazard of waste, in decontamination of territories, water areas and land zoning according to the criteria of natural or anthropogenic Hg accumulation.

Exposure of Arctic populations to methylmercury from consumption of marine food: an updated risk-benefit assessment

Recent and powerful epidemiological studies have been used as a basis for revising international and domestic guidelines for human exposure to mercury. Long-range transport of mercury into the Arctic makes some Arctic peoples consuming traditional marine foods, especially newborns, children and pregnant women, very vulnerable to harmful exposures. The WHO, the USEPA and Health Canada have all recently revised their mercury intake guidelines as a result of neurological effects reported in children exposed in utero and adults. Guidance values are equivalent to 0.23 microg/kg-bw/d, 0.1 microg/kg-bw/d and 0.2 microg/kg-bw/d respectively. Differences between the numbers represent slight differences in the uncertainty factors applied, rather than in toxicological interpretation. More recent findings suggest that mercury may also be a factor in ischemic heart disease, which could lower guidance values in the future. Considering the benefits of marine fatty acids (n-3 fatty acids) and guidance that populations consume 300-400g fish/week, consumers face a reality that most open ocean and relatively 'unpolluted' fish species contain levels of mercury that would lead to exposures at current guidance levels. Clearly, there is no more room for further mercury pollution and there is an urgent need for international action to reduce mercury emissions. Concomitantly, while there may be a need for public health authorities to provide consumption advisories to some highly exposed populations, such as in the Arctic, there remains a need to better understand the interactions and benefits associated with marine foods that may reduce health risks associated with low-level mercury exposure.

[Differential diagnostic method of initial implications and degree I of the chronic mercury intoxication]

Currently available methods for diagnosis of chronic mercury intoxication (CMI) are applied at the any stage of the disease. Changes in these indices sometimes have no the specificity for any CMI stage, and a conclusion on them has the descriptive character. In addition, the above mentioned methods possess not sufficiently high accuracy in the diagnosis of intoxication at early stages of the development of the disease. The purpose of the research is the development of the method permitting to make the differential diagnosis between the initial symptoms of mercury poisoning and its first degree. 118 men who work/worked in the contact with mercury vapor were examined. There were evaluated electroencephalogram, long-latency auditory and cognitive evoked potentials, cerebral hemodynamics, noradrenaline (NA)content in the blood plasma. Statistical processing was performed with the use of «Statistica 6.0» software. The levels of NA in the development of CMI were shown to increase, by the time of the shaping of this disease the noted change was decompensated in the nature. The study of reactivity of cerebral vessels revealed the presence of abnormal responses during hypercapnic load in 14 - 24% of examined cases. In the analysis of auditory evoked potentials there was established the change in indices of latency and amplitude of the V- wave, which pronounced in the prolong response time, significant elongation in the P1 peak latency and the gain in the latency of N1 peak. There was established the presence of the wave-like change in the index of the latency of P300. In workers without an occupational disease, there was noted the marked elongation of the latent period of cognitive potential, while in patients with the newly made diagnosis the latency of P300 corresponded to standard values, and in the long term there was observed a sharp deterioration in this index. With the aid of the discriminant analysis with the calculation of canonical value there were revealed the most informative neurobiochemical indices, reoencephalogric ones and evoked potentials. The developed method of diagnosis allows to distinguish between the initial symptoms of mercury intoxication and the first stage of the disease.

Ameliorative stroke of selenium against toxicological effects of mercuric chloride in liver of freshwater catfish Heteropneustes fossilis (Bloch)

Mercury, a prevalent and unrelenting toxin, occurs in a variety of forms in freshwater as well as, in marine life. Mercury is an important inducer of oxidative stress in fish leading to formation of reactive oxygen species. Selenium is an essential micronutrient for animals and has antagonistic effect against mercuric toxicity in fishes. Present study has been made to evaluate toxic effect of HgCl2 (0.15 mg/L) on liver of freshwater catfish Heteropneustes fossilis (Bl.). Protective ability of selenium has been investigated by simultaneous exposure of fish with sodium selenite (0.15 mg/L) along with mercuric chloride. For present study Fishes were divided into three groups of ten fishes each the first group served as control, while the second group fish were exposed to HgCl2 . Animals of third group were treated with HgCl2 and Na2 SeO3 . Results reveal that mercury induced lipid peroxidation and in response to this, antioxidants reduced glutathione (GSH) and Catalase (CAT) were reduced whereas, Glutathione reductase (GR) level was enhanced. These antioxidants scavenge the reactive oxygen radicals. Hg induced histopathological damage and elevation in alkaline phosphatase (ALP) and transaminases and reduction in protein and glucose contents were evidently seen in catfish liver. Intriguingly, results indicate that under stress of mercury, the fish actively generate oxidative stress and antioxidant responses, which can be used as biomarkers of pollution. Simultaneous exposure to Selenium along with Hg suppressed Hg uptake and lipid peroxidation. Histological architecture and all biochemical parameters were maintained near normal in the presence of selenium in liver of the catfish.

Parenteral nutrition as an unexpected and preventable source of mercury exposure in preterm infants

Perinatal mercury exposure has neurodevelopmental consequences, which may be worse in preterm infants. In our cohort (N = 60), maternal and infant prenatal exposures were low, but infant levels increased during hospitalization and correlated only with duration of parenteral nutrition. A non-negligible exposure resulted from the nutrition preparation on equipment shared with adult preparations.

The welfare value of FDA's mercury-in-fish advisory: a dynamic reanalysis

Assessing the welfare impact of consumer health advisories is a thorny task. Recently, Shimshack and Ward (2010) studied how U.S. households responded to FDA's 2001 mercury-in-fish advisory. They found that the average at-risk household reduced fish consumption by 21%, resulting in a 17%-reduction in mercury exposure at the cost of a 21%-reduction in cardioprotective omega-3 fatty acids. Based on a static assessment of the health costs and benefits Shimshack and Ward concluded that the advisory policy resulted in an overall consumer welfare loss. In this note, we propose a dynamic assessment that links the long-term cardiovascular health effects of the advisory to life-cycle consumption. We find that under reasonable assumptions the welfare loss might be much larger than suggested. Our analysis highlights the importance of accounting for dynamic effects when evaluating persistent changes in exposure to environmental health risks.

Ameliorating effect of β-carotene on antioxidant response and hematological parameters of mercuric chloride toxicity in Nile tilapia (Oreochromis niloticus)

The impact of different levels of dietary β-carotene to alleviate the effect of mercuric chloride toxicity in Nile tilapia was assessed. Semi-purified diets containing 0, 40, and 100 mg β-carotene kg(-1) dry diet were fed for 21 days, which were subjected to sublethal concentration of mercuric chloride (0.05 ppm). Hematological and biochemical parameters, lipid profile, and antioxidant response were examined. All hematological parameters of tilapia fish starting from second week of toxicity were significantly decreased. A significant increasing trend in liver enzymes (ALT and AST) were observed parallel to the time of toxicity and peroxide radicals (MDA) appearing significantly increased in toxicated group without carotene supplement, although carotene supplementation return all parameters within the control levels. Mercury accumulated significantly in fish liver and white muscles in toxicated group while it showed a significant reduction in dietary β-carotene-treated group. Overall, it can be used as immunostimulant and alleviate the suppression effect resulted from immune depressive stressful condition in farmed Nile tilapia.

Mercury Reduction in Munhena, Mozambique: Homemade Solutions and the Social Context for Change

The health and environmental impacts of artisanal gold mining are of growing concern in Munhena, Mozambique, where more than 12,000 people are involved in such activities. Gold is extracted using mercury amalgamation, posing a considerable threat to human and environmental health. A pilot project ascertained the feasibility of reducing mercury use and emissions by promoting control measures utilizing local resources. Retorts were fabricated with local materials. Training workshops introduced the homemade retorts, and a portable mercury monitor revealed effective mercury reduction. Barriers to widespread technology adoption include poverty, lack of knowledge and trust, and the free supply of mercury from private gold buyers. Homemade retorts are inexpensive and effective, and miners could benefit by building community amalgamation centers. The government could play a greater role in gold purchasing to reduce mercury pollution.

Skin-lightening practices and mercury exposure in the Somali community

Somali women often use creams and soaps to lighten skin tone, fade freckles or get rid of age spots. Use of these products raises a health concern, as some have been found to contain mercury. This article describes an investigation that involved interviewing Somali women about skin-lightening practices and the products they use and then testing those products for mercury. Twenty-seven samples of products purchased at markets in Minneapolis and St. Paul were analyzed bythe Minnesota Department of Health for specific mercury levels. Eleven of the 27 (47%) were found to contain mercury. Some exceeded the current FDA threshold of 1 part per million. This has prompted both state and federal health officials to issue warnings about the use of these products.

Fish consumption patterns and mercury exposure levels among women of childbearing age in Duval County, Florida

Consumption of fish containing methylmercury can pose serious health concerns including neurotoxic effects in adults and toxicity to the fetuses of mothers exposed during pregnancy. In the study described in this article, the authors examined fish consumption patterns and measured hair mercury levels of women of childbearing age in a coastal county in Florida. Women from the community participated in a risk factor assessment survey (N = 703). Hair samples (n = 698) were collected and analyzed for mercury. The authors identified 74.8% below detection limit; 25.2% had detectable limits of mercury, while 7% exceeded 1 pg/g. Hair mercury levels increased with fish consumption and age. Race, income, and education levels were also associated with increased hair mercury levels. Women of Asian/Pacific Islander origin had the highest levels. Although reported fish consumption exceeded the recommendations for women of childbearing age, the study population had lower mercury levels than other comparative studies in Florida and at national levels.

[Management of wastes from dental amalgam by dentists in Burkina Faso and Morocco]

Dental amalgam is a metallic restorative material that is used for direct filling of carious lesions since many years. The use of this material generates solid and particulate wastes that present potential challenges to the environment. This study was carried out to assess amalgam use and waste management protocols practiced by Moroccan and Burkinabe dentists. A cross-sectional study was made of 79 in Rabat, Sale and Temara in Morocco and 56 in Ouagadougou, Bobo-Dioulasso in Burkina-Faso. The results showed that 69.5% of dental amalgam waste in Morocco vs 49.9% in Burkina-Faso was disposed with household waste which is a problem for both the environment and a risk to human being. Proper methods of dental amalgam waste disposal should be carried out to prevent indirect mercury poisoning for human.

Role of Glutathione in protection against mercury induced poisoning

Mercury is harmless in an insoluble form, such as mercuric sulfide, but it is poisonous in soluble forms such as mercuric chloride or methylmercury. Mercury is a neurotoxin. Outbreaks of mercuric chloride poisonings have made it clear that adults, children, and developing fetuses are at risk from ingestion exposure to mercury. It is very important and interesting to study the reaction of mercuric chloride and Glutathione as biomarker of Glutathione role in detoxification and conjugation in components (Plasma and Cytosolic Fraction). The effect of mercuric chloride's different concentrations was examined on GSH present in plasma and cytosolic fraction. Decrease in GSH level was dependant on mercuric chloride concentration. The decrease in GSH level of blood components was more prominent with the time of incubation of mercuric chloride. Decrease in the concentration of reduced state Glutathione may be due the interaction of reduced state Glutathione (GSH) and mercuric chloride to form oxidized Glutathione (GSSG) or mercuric-glutathione complex. This change in GSH metabolic status provides information regarding the role of GSH in detoxification of mercuric chloride. The effect of mercury metal on Glutathione in blood components has been discussed in this paper in vitro condition as a model for in Vivo condition.

Fish consumption and advisory awareness among the Philadelphia Asian community: a pilot study

Difficulties in the risk communication of fish consumption arise from the concept that this consumption can have both harmful and beneficial effects. This is particularly an issue among populations for which seafood is a major dietary and cultural component. Fish advisories are an important tool in preventing overconsumption of fish that have elevated concentrations of toxic contaminants. The exploratory pilot study described in this article examined fish consumption patterns and knowledge of the potential health risks associated with overconsumption of mercury-contaminated fish within a limited (N = 34) sample of the Philadelphia Asian-American population. Study data were used to evaluate the efficacy of state-issued advisories designed to encourage safe levels of fish consumption within the study population. Results indicate that while advisory awareness levels among study participants were greater than previously observed in Asian-American populations, consumption levels remained high. The limited findings of the authors' study, in combination with existing evidence, suggest the need for the development of more effective methods of disseminating advisory information.

[Overview of studies on detoxification effect of smilacis glabrae rhizoma on mercury poisoning]

Mercury-containing preparations are widely used in surgery department of traditional Chinese medicine and have made remarkable achievements. But they are toxic to human kidney, nerve, immune, etc. Smilacis Glabrae Rhizoma is sweet, tasteless and neutral in nature and able to enter liver and stomach channels and detoxify mercury poisoning. This article summarizes the mercury poisoning and the detoxification effect of Smilacis Glabrae Rhizoma in ancient records, pharmaceutical studies and clinical application, in order to provide ideas and methods for the safe use of mercury-containing preparations in surgery department of traditional Chinese medicine.

[Fish and seafood as a source of human exposure to methylmercury]

Fish and seafood are recommended diet constituents providing high quality protein, vitamins, minerals and omega-3 fatty acids, mainly eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). However, these foodstuffs can also be the major source ofmethylmercury intake in humans. In general, more than 90% of the mercury in fish is found as methylmercury, but contents of methylmercury can vary considerably between species. Predatory species that are at the top of the food chain and live a long time, may accumulate higher levels of methylmercury. This paper contains information about sources of human exposure to organic compounds of mercury, toxicity, metabolism and transformation of mercury in the environment. Assessment of methylmercury by international risk assessment bodies such as the Joint FAO/WHO Expert Committee on Food Additives (JECFA) and U.S. National Research Council (NRC) were presented. Climate changes and their influence on the mercury cycle in the environment especially mercury methylation and concentrations of methylmercury in marine species were also presented. Consumer advice prepared by European Commission and Member States as regards consumption of predatory fishes such as swordfish, tuna, shark, marlin and pike, taking into account the most vulnerable groups of population e.g. women planning pregnancy, pregnant or breastfeeding women and children were presented. Mercury and methylmercury contamination of fishes and seafood on the basis of the literature references as well as intake of mercury with fish and fish products in Poland and other European country were discussed. The role of selenium as a factor which counteracts methylmercury toxicity and protects against some neurological effects of methylmercury exposure in humans, as well as information on potential etiological factors connected with autism disorder were also described. Attention has also been drawn to increasing number of notifications to Rapid Alert System for Food and Feed (RASFF) concerning the contamination of fish and fish products with total mercury. European and national regulations concerning maximum permissible levels of mercury in food were also presented. Possibility of selection of different fish and seafood species, taking into account low methylmercury contamination and high contents of omega-3 fatty acids e.g. sardine, mackerel, anchovy, salmon, periwinkle, have been discussed.

Fish advisories in the USA and Japan: risk communication and public awareness of a common idea with different backgrounds

Some countries have established fish advisories to manage fish consumption to minimize methylmercury exposure. Our objective was to compare the fish advisories and the resultant consumer behavior in the United States of America (USA) and Japan. Both countries have national consumption guidelines, but American states enjoy greater independence in issuing guidelines for local water bodies and vary in the information that is provided for the public. The proportion of the American public that has heard of state fish advisories is thought to be close to 30%. There is a concern that this low level of awareness extends to pregnant women. In Japan, the current problem is the lack of comprehensive studies on the public awareness of fish advisories. Nonetheless, there is evidence that fish consumption has decreased in both countries. In USA, there is a possibility that the strong emphasis on mercury toxicity drives the general population towards a trend of lower fish consumption. In Japan, the fish advisory encourages seafood consumption for nutritional benefits. Consequently, the decrease may be due to the shift towards a "Western diet". Also, the Japanese fish advisory seems to be less active in advocating the issue of fish consumption and mercury exposure, which may be partly responsible for the possible lesser attention of the consumers. Cultural factors may explain for the baseline difference in consumption and account partly for the change in Japanese consumer behavior. However, the dissimilarities in fish advisories may also be responsible for the variations in consumer behavior.

SUICIDAL MERCURY INJECTION INTO THE UPPER LIMB: A CASE STUDY

We report a rare case of self-injection of mercury into the subcutaneous tissue of the upper limb. A multi-disciplinary management approach was adopted including cooperation between toxicologists, orthopaedic surgeons, radiologists and environment safety personnel. Surgical removal of mercury under radiological screening and systemic intoxication treated by chelating agents, namely dimercaprol and succimer. Serial serum and urine mercury levels showed an initial rise despite surgical removal and returned to normal after a prolonged period of time. Safety precautions were taken during surgery to avoid inadvertent intoxication of staff. Contamination of the operation theatre was monitored by the amount of mercury vapour released into the air. All personnels involved in the management of the patient did not show any evidence of mercury intoxication.

Delayed biochemical changes induced by mercury intoxication are prevented by zinc pre-exposure

This work evaluated the delayed effects of mercury and the effectiveness of zinc in preventing such effects. Pups were pre-treated with 1 daily dose of ZnCl(2) (27 mg/kg/day, by subcutaneous injections) from 3rd to 7th postnatal day and received 1 daily dose of 5 mg/kg of HgCl(2), for 5 subsequent days (8-12 days old). Animals were euthanized 21 days after the end of Hg-exposure. Porphobilinogen-synthase activity as well as zinc and mercury contents was determined in the liver and kidneys. Alanine aminotransferase, aspartate aminotransferase and lactic dehydrogenase activities as well as urea, creatinine and glucose levels were analyzed in plasma or serum. Some animals were considered more sensitive to mercury, since they did not recover the body weight gain and presented an increase of renal and hepatic mercury content, urea and creatinine levels; a decrease in renal porphobilinogen-synthase and alanine aminotransferase activities, as well as a decrease in the liver and an increase in kidney weights. Some animals were considered less sensitive to mercury because they recovered the body weight and presented no biochemical alterations in spite of mercury in the tissues. Zinc prevents partially or totally the alterations caused by mercury even those that persisted for a long time after the end of exposure. These findings suggest that there is difference among the animals regarding the sensitivity to mercury.

Mercury exposure education provided by women's health clinics in Duval County, Florida

Duval County (Jacksonville, FL, USA) has a long history of environmental health hazards, especially prevalent within its urban core, referred to as Health Zone 1. In 2009, the Duval County Health Department conducted a survey of awareness of and actual exposure to methylmercury among women in the county. The survey found that women with more education or higher incomes had a higher awareness of potential mercury exposures. Furthermore, women in the urban core were less aware and had higher exposure than those in more affluent areas. This study assesses the mercury-exposure awareness and education by healthcare providers serving women of child-bearing age. We surveyed 28 women's health clinic offices. Sixty-one percent (17/28) indicated that they provide mercury exposure education to female patients, either written or verbal. Of these, only half (8/17) provide written education materials. Ninety-three percent of the providers indicated that a benefit to providing education on mercury exposure, is having "healthier developing fetuses and young children in the community". Two barriers identified by providers to offering information on mercury exposure and risk were (a) a lack of interest among patients, and (b) a lack of clear, understandable educational materials. The long-term goal of our * -8project is to develop and distribute culturally effective, low literacy materials for distribution by health clinics, to document the increased awareness of mercury exposure risks, and to lessen the adverse health outcomes that may result from mercury exposure among vulnerable population groups in Duval County.

N-acetylcysteine pretreatment ameliorates mercuric chloride-induced oxidative renal damage in rats

The effectiveness of the antioxidant thiol, N-acetylcysteine (NAC), in enhancing methylmercury (CH3HgCl) excretion and its utility as a possible antidote in CH3HgCl poisoning has been reported. NAC, however, has been reported to be ineffective in accelerating excretion of divalent toxic metals, including inorganic mercury, Hg2+. In this study, we evaluated the possible protective effect of short-term pretreatment with NAC against mercuric chloride (HgCl2) toxicity in rat model. This is aimed at determining its chemopreventive or prophylactic benefit in situations of high risk exposure (occupational/industrial) to mercury. Rats were divided into three treatment groups. Group I received saline (10 ml/kg) and served as control. Group II received HgCl2 (5mg/kg) and group III received NAC (10mg/kg) plus (5mg/kg). All administration was via intraperitoneal (i.p.) injection. Saline and NAC were administered for 5days and HgCl2 was administered to rats in groups II and III on the 5th day. Animals were sacrificed 24 hours after HgCl2 injection and samples obtained for biochemical evaluation. Results revealed that single i.p. injection of HgCl2 induced significant renal oxidative damage resulting in significant decrease in the activities of superoxide dismutase (SOD), catalase (CAT), glutathione-s-transferase (GST), depletion of reduced glutathione (GSH) and increase in malondialdehyde (MDA) levels in these rats. The activities of glucose-6-phosphatase (G6Pase) and 5'-nucleotidase (5'-NTD) (markers of microsomal damage) also decreased in these HgCl2 treated rats. The oxidative damage induced by HgCl2 led to significant alterations in renal histology and caused functional impairment (indicated by elevated blood urea nitrogen (BUN) and serum creatinine) in these rats. NAC was effective in attenuating the oxidative damage, functional impairments and histopathological changes that characterized HgCl2 intoxication in this study. Renal antioxidant defense system was re-enforced by NAC, leading to increase in the activities of SOD, CAT, GST and decreases in GSH depletion and MDA level. Our results therefore reveal the ameliorative effect of NAC pretreatment against HgCl2 toxicity in vivo, thus, suggesting its usefulness as a possible chemoprophylactic agent during occupational or industrial exposure to inorganic mercury.

Assessment of mercury in muscle of fish from Cartagena Bay, a tropical estuary at the north of Colombia

Fish belonging to several trophic levels from Cartagena Bay, a tropical estuary, were collected and analyzed for total mercury (T-Hg) concentrations in muscle. T-Hg concentrations varied from 0.010-0.526 microg/g, and the overall average was 0.051 +/- 0.002 microg/g. Carnivorous species presented the highest T-Hg mean value (0.100 +/- 0.006 microg/g), followed by omnivorous (0.076 +/- 0.014 microg/g) and detritivorous (0.028 +/- 0.001 microg/g). The relationships between weight and T-Hg content were found for the carnivorous species Sciades herzbergi (r = 0.508, p < 0.001) and not for the detritivorous Mugil incilis (r = 0.086, p = 0.207). Although results suggest fish from the bay pose a low health threat for humans in terms of Hg exposure, vulnerable groups such as pregnant women, should avoid eating large size carnivorous species. Knowledge about species with low Hg content should be widespread within fishing communities, guaranteeing adequate nutrition by including fish in the diet and reducing the risk of Hg poisoning.

[The levels of mercury in fish industry]

Among a wide spectrum of heavy metals, mercury is one of the most toxic ones that have a negative effect. The studies of hydrocoles have ascertained a certain association of the fish content of mercury with the pollution of water spaces. The content of mercury in finished fish products can be reduced, by correctly choosing manufacturing operations.

Mercury toxicity and the mitigating role of selenium

Mercury is a well-known environmental toxicant, particularly in its most common organic form, methylmercury. Consumption of fish and shellfish that contain methylmercury is a dominant source of mercury exposure in humans and piscivorous wildlife. Considerable efforts have focused on assessment of mercury and its attendant risks in the environment and food sources, including the studies reported in this issue. However, studies of mercury intoxication have frequently failed to consider the protective effects of the essential trace element, selenium. Mercury binds to selenium with extraordinarily high affinity, and high maternal exposures inhibit selenium-dependent enzyme activities in fetal brains. However, increased maternal dietary selenium intakes preserve these enzyme activities, thereby preventing the pathological effects that would otherwise arise in their absence. Recent evidence indicates that assessments of mercury exposure and tissue levels need to consider selenium intakes and tissue distributions in order to provide meaningful risk evaluations.

[About the history chemistry and potassium iodide]

Louis Melsen was born at Louvain, he spent four years in Paris, working in Dumas's laboratory. Four letters from Melsens to Chevreul, since 1951 to 1880, are commented on. Two letters relate to Van Helmont and common interest of the two scientists in history of sciences. The others recall Melsens's proposal that potassium iodide can cure and prevent lead and mercury poisoning, and Chevreul's researches about colours seeing.

Comparative evaluation of the protective effect of selenium and garlic against liver and kidney damage induced by mercury chloride in the rats

The present study was designed to compare the protective effect of selenium and garlic against liver and kidney damage induced by (ip) injection of 0.5 mg/kg mercury chloride (HgCl(2)) in rats. Thirty-six Sprague-Dawley rats were used in the present experiment and divided into six groups: one group was orally given (1 ml) saline and served as a control group; two groups of rats were given either selenium (0.1 mg/kg) or garlic (63 mg/kg) alone, once daily an oral dose for 30 successive days; other two groups of rats were given either selenium or garlic alone, once daily a dose for 15 successive days prior to HgCl(2) injection and on the next 15 successive days simultaneously with HgCl(2) injection; and the last group of rats was injected ip with HgCl(2) for 15 days and at the end of the experiment (which lasted 30 days), blood samples for the biochemical analysis were obtained from all rats after being lightly anesthetized with ether, and specimens of kidney and liver were removed and prepared for histochemical study. Computer image analysis was applied to liver and kidney tissues to evaluate the DNA density and DNA ploidy pattern in different groups. The results revealed that the rats injected with HgCl(2) showed a significant increase in levels of blood urea nitrogen (BUN), serum creatinine, alanine aminotransferase (ALT), aspartate aminotransferase (AST) by 29.3%, 62.5%, 29.46% and 30.61%, respectively, while alkaline phosphatase (ALP) showed a significant decrease by 22.6% as compared with saline control group. Rats that were given selenium in combination with the HgCl(2) injection showed a significant decrease in BUN, Serum creatinine, ALT and AST levels, while ALP was significantly increased as compared with HgCl(2) group. Also rats that were given garlic in combination with HgCl(2) injection showed a significant decrease in BUN, Serum creatinine, ALT and AST levels, although serum ALP level showed an increase as compared to HgCl(2) group. Rats that had been orally administered selenium or garlic alone did not show any significant changes in the serum level of BUN, Serum creatinine, ALT and AST but there was a significant decrease in ALP level as compared with saline control group. The cytometric results revealed that injection of HgCl(2) induced an increase in the DNA density in kidney tissues with an increase in aneuploid cells and decrease in diploid cells. However, DNA density decreased in liver tissues with mild decrease in diploid cells and little percentage of aneuploid cells. We can conclude that oral administration of either selenium or garlic produces a significant protection against liver and kidney damage induced by the HgCl(2) injection, but garlic appears to be more protective.

Demonstrating reverence for the earth

As a community hospital and a major employer, St. Mary's Hospital Medical Center in Green Bay, Wisconsin, assumes responsibility not only for the health of people in the community but also for the health of the environment in which they live. Demonstrating reverence for the earth is a primary strategic goal, originating with its sponsoring organization, Hospital Sisters Health System, Springfield, Illinois. St. Mary's Hospital Medical Center is one of 13 hospitals in this system dedicated to healing ministries. Healing the earth is as important to this mission as is prevention and treatment to heal the human body. Over the past 25 years, St. Mary's Hospital Medical Center has brainstormed and implemented innovative ideas to mend the earth, improving the health of air, water, and land, and ultimately improving the health of the people who come into contact with our dynamic environment. It is a passion and commitment of time and resources, but one in which there is no question that it is the right thing to do.

Strong poison revisited

Selenium in the form of selenocysteine plays an essential role in a number of proteins, but its role in non-enzymatic biochemistry is also important. In this short review we discuss the interactions between inorganic selenium, arsenic and mercury under physiological conditions, especially in the presence of glutathione. This chemistry is obviously important in making the arsenic and mercury unavailable for more toxic interactions, but in the process it suggests that a side-effect of chronic arsenic and/or mercury exposure is likely to be functional selenium deficiency.

Subchronic heavy metal and alcohol treatment in rats: changes in the somatosensory evoked cortical activity

Young adult male Wistar rats were treated, by gavage, with 80 or 320 mg/kg Pb2+ (lead acetate), 0.4 or 1.6 mg/kg Hg2+ (mercuric chloride) or both by combining the lower doses. For combination with alcohol, ethanol was added to the rats' drinking water in 5 v/v %. After 12 weeks of treatment, electrophysiological recording was made from the somatosensory cortex in urethane anaesthesia. Evoked potentials obtained by stimulation of the whiskers were recorded. Both metals, and alcohol alone, increased significantly the latency of the evoked response. Alcohol seemed to abolish the effect of Pb, but not of Hg. Fatigue, calculated form the response amplitude, was increased by Pb and Hg treatment and this effect of Hg was reduced by ethanol. Evoked activity and its dynamic characteristics were sensitive to the complex neurotoxic effect induced in the rats and can provide a basis for developing functional markers.