Mercury

“Kidney injury from mercury is known to cause dose-related tubular dysfunction and idiosyncratic nephrotic syndrome according to various case reports. Motivated by a patient with subacute-onset nephrotic syndrome, histologic features of secondary focal segmental glomerulosclerosis, and concurrent mercury toxicity, we conducted a systematic review to explore renal histologic changes in patients with toxic mercury exposures and nephrotic syndrome. Data were extracted from a patient’s clinical record. MEDLINE/Ovid was searched from 1950 to November 2010 using a prespecified search strategy. Two nephrology textbooks and the UpToDate online database also were searched. Inclusion criteria were studies of humans with nephrotic syndrome, nephrotic-range proteinuria, or kidney biopsy results reported. There were no exclusion criteria. We identified 27 other reports of 42 patients with nephrotic syndrome or nephrotic-range proteinuria. Of the 26 individuals, including our patient, who underwent kidney biopsy, histology showed glomerular disease in 21. Of these 20 biopsies, 4 showed minimal change disease and 15 showed membranous glomerulonephritis. Mercury exposure can lead to various glomerular lesions; we emphasize the importance of a careful occupational and dietary history in elucidating a cause for the undetermined nephrotic syndrome.”

OBJECTIVE:
The objective of this study was to quantify the relationship between number of dental amalgam surfaces and urinary mercury levels.

METHODS:
This study uses participant data from a large philanthropic chronic disease prevention program in Calgary, Alberta, Canada. Urine samples were analysed for mercury levels (measured in μg/g-creatinine). T-tests were used to determine if differences in urine mercury were statistically significant between persons with no dental amalgam surfaces and one or more dental amalgam surfaces. Linear regression was used to estimate the change in urinary mercury per amalgam surface.

RESULTS:
Urinary mercury levels were statistically significantly higher in participants with amalgam surfaces, with an average difference of 0.55 μg/g-creatinine. Per amalgam surface, we estimated an expected increase of 0.04 μg/g-creatinine. Measured urinary mercury levels were also statistically significantly higher in participants with dental amalgam surfaces following the oral administration of 2,3-dimercaptopropane-l-sulfonate (DMPS) and meso-2,3-dimercaptosuccinic acid (DMSA) which are used to mobilize mercury from the blood and tissues.

DISCUSSION:
Our estimates indicate that an individual with seven or more dental amalgam surfaces has 30% to 50% higher urinary mercury levels than an individual without amalgams. This is consistent with past literature that has identified seven amalgam surfaces as an unsafe level of exposure to mercury vapor. Our analysis suggests that continued use of silver amalgam dental fillings for restorative dentistry is a non-negligible, unnecessary source of mercury exposure considering the availability of composite resin alternatives.

“Following the recently agreed Minamata Convention, a phase-down in the use of dental amalgam will become a priority for the profession. With a lead-in period of a number of years, important changes in the mind-set of the profession are required to ensure that patient safety is not compromised. Posterior composites have been a viable, and in many cases preferable, alternative to amalgam for many years. However, notwithstanding considerable developments in dental school teaching on the application and placement of posterior composites, growing evidence to support the use of composites in the restoration of posterior teeth and advances in composite systems, many practitioners remain reluctant to place composite rather than amalgam. This paper considers the present and future use of posterior composites and highlights ways in which dental school teaching and continuing professional development (CPD) may contribute to the successful phase-down, and now inevitable discontinuation, in the use of dental amalgam.”

“The announcement of the Minamata Convention has triggered the lead into a phase-down in the use of dental amalgam. This paper considers aspects of this development in the context of the experience of banning the use of dental amalgam in Norway. It is suggested that strong top-down leadership and joined-up working by all relevant stakeholders, including patients, may be one of the most important keys to an effective, seamless transition to the provision of preventatively orientated, patient-centred, minimally interventive operative dentistry, based on state-of-the-art selection and application of tooth-coloured restorative materials. The benefits of such a transition are considered to be an important goal for dentistry in the UK.”

“The trouble with human beings is that virtually everything we do interrupts up some ecological or natural system and as an activity, dentistry is no exception. It stands to reason then that we are not going to either change our ways overnight, or the impact that they make. However, there are steps that we can take to modify, slightly soften and possibly engender a small and definite difference to the environmental stress that we cause. What can we do? ‘It’s the practice, stupid’.”

OBJECTIVES: The aim of this study was to describe the mercury concentrations in female hairdressers associated with occupational and environmental exposure through cosmetic products and amalgam fillings.

METHODS: Sixty-two hair and nail samples were collected randomly from Iranian hairdressers. Hg level determination was carried out using a LECO, AMA 254, Advanced Mercury Analyzer according to ASTM, standard No. D-6722.

RESULTS: The mean mercury levels were 1.15 ± 1.03 ug/g and 1.82 ± 1.12 μg/g in the hair and nail samples, respectively with a positive correlation among them (r=0.98). A significant relation was also observed between Hg levels and the number of amalgam fillings (p<0.001), use of cosmetics (p<0.001), and use of gloves (p=0.02).

CONCLUSIONS: The Hg levels in about one-third of the studied samples were higher than the USEPA-recommended 1 ug/g, which represents a serious health risk. Hairdressers with continuous use of cosmetics and a high number of amalgam fillings had significantly elevated mercury concentrations in their hair and nails, suggesting the importance of mercury exposure assessment in hidden, less-explored sources of Hg in the workplace.

“Due to possible health risks, quantification of mercury accumulation in humans was included in the Flem-ish biomonitoring programmes FLEHS I (2002–2006) and FLEHS II (2007–2011). The general objectiveof FLEHS I was to assess regional exposure levels in order to link possible differences in these internalexposure levels to different types of local environmental pressure. Therefore, Hg and MMHg (methylmer-cury) were only measured in pooled blood samples per region and per age class. In FLEHS II, mercuryconcentrations were measured in hair of each participant. About 200 adolescents and 250 mothers (ref-erence group) and two times 200 adolescents (2 hotspots) were screened. The main objectives of theFLEHS II study were: (1) to determine reference levels of mercury in hair for Flanders; (2) to assess rela-tions between mercury exposure and possible sources like fish consumption; (3) to assess dose–effectrelations between mercury exposure and health effect markers. The results showed that mercury con-centrations in the Flemish population were rather low compared to other studies. Mercury levels in the Flemish populations were strongly related to the age of the participants and consumption of fish. Significant negative associations were observed between mercury in hair and asthma, having received breastfeeding as a newborn, age at menarche in girls, allergy for animals and free testosterone levels. Significant correlations were also observed between mercury in hair and genes JAK2, ARID4A, Hist1HA4L (boys) andHLAdrb5, PIAS2, MANN1B1, GIT and ABCA1 (girls).”

“Thimerosal, an organomercury compound, has been widely used as a preservative. Therefore, concerns have been raised about its neurotoxicity. We recently demonstrated perturbation of early serotonergic development by prenatal exposure to thimerosal (Ida-Eto et al. (2011) [11]). Here, we investigated whether prenatal thimerosal exposure causes persistent impairment after birth. Analysis on postnatal day 50 showed significant increase in hippocampal serotonin following thimerosal administration on embryonic day 9. Furthermore, not only serotonin, striatal dopamine was significantly increased. These results indicate that embryonic exposure to thimerosal produces lasting impairment of brain monoaminergic system, and thus every effort should be made to avoid the use of thimerosal.”

“The aim of the study was to determine the content of mercury both in sick (cancerous) and healthy men in relation age and state of health. The samples coming from men lived in Cracow and area around of the city. Healthy tissues were collected during autopsy, cancerous tissues during surgery.
The content of mercury in the samples was measured using cold vapor atomic absorption spectrometry method (CVAAS). The fragments of esophagus, stomach, small intestine, large intestine, liver, pancreas, kidney, bladder and skin tissues (healthy tissues) and stomach, large intestine, kidney and bladder (cancerous tissues), were placed in a special crucible directly after defrosting and weighing.
The average mercury content in healthy men was significantly higher in the age group 51-90 years old (0,027 ppm), compared to young men (0,008 ppm). Similar differences were obtained for sick men – older men have a slightly higher content of mercury in the organs (0,106 ppm) than men younger (0,088 ppm).”

“IMPORTANCE:
To date, this is the first population-based study to examine the recurrence risk for autism spectrum disorders (ASDs), including time trends, and the first study to consider the ASDs recurrence risk for full- and half-siblings.

OBJECTIVES:
To estimate the relative recurrence risk for ASDs in a Danish population, including recurrence in full- and half-siblings, and to examine time trends in ASDs relative to the recurrence risk.

DESIGN, SETTING, AND PARTICIPANTS:
Population-based cohort study in Denmark. All children (about 1.5 million) born in Denmark between January 1, 1980, and December 31, 2004, were identified and followed up to December 31, 2010. We identified a maternal sibling subcohort derived from mothers with at least 2 children and a paternal sibling subcohort derived from fathers with at least 2 children.

EXPOSURES:
Children having an older sibling with ASDs are compared with children not having an older sibling with ASDs.

MAIN OUTCOMES AND MEASURES:
The adjusted hazard ratio for ASDs among children having an older sibling with ASDs compared with children not having an older sibling with ASDs. RESULTS The overall relative recurrence risk for ASDs was 6.9 (95% CI, 6.1-7.8), and it did not change significantly over time; similar risks were observed in maternal and paternal full-siblings. The relative recurrence risks were 2.4 (95% CI, 1.4-4.1) for maternal half-siblings and 1.5 (95% CI, 0.7-3.4) for paternal half-siblings.

CONCLUSIONS AND RELEVANCE:
Our population-based recurrence risk estimate is lower than the recently reported estimates from clinical samples. Our results demonstrate no time trend in the ASDs recurrence risk as seen in the ASDs prevalence. The difference in the recurrence risk between full- and half-siblings supports the role of genetics in ASDs, while the significant recurrence risk in maternal half-siblings may support the role of factors associated with pregnancy and the maternal intrauterine environment in ASDs.”