RESUMO
CONTEXT AND OBJECTIVE: Periodontitis and type 2 diabetes (T2D) are chronic diseases generally treated with conventional therapies alone. The aim of this study was to compare the effects of homeopathy as an adjunct to conventional periodontal therapy in individuals with periodontitis and T2D. DESIGN: 85 individuals, age between 35 and 70 years, of both genders, participated in this randomized study; 70 patients were from the Institute of Endocrinology and Diabetes of Rio de Janeiro, Brazil. They were divided into 2 groups: G1, individuals with periodontitis without systemic conditions; and G-2, individuals with periodontitis and T2D. Both groups received homeopathic treatment and were evaluated in clinical and laboratory examinations. The medication used was chosen based on the similarity principle: Berberis 6CH, Mercurius Solubilis/Belladona /Hepar Sulfur and a Pyrogenium 200CH biotherapic. Medications were prescribed in diluted low ultra-diluted concentration doses for all signs and symptoms, while biotherapics were used for chronic stimulation. SETTING: The study was performed in Brazil by university research professors of homeopathy and periodontics. RESULTS: Both groups showed significant clinical and laboratory improvements during the study from baseline to 1 year with reductions in total cholesterol (total-C), triglycerides, glucose, glycated hemoglobin (A1cHb), uric acid and C-reactive protein (CRP). Statistical and descriptive analyses were performed. For most parameters, G1 performed better than G2 (P < .05). CONCLUSION: Homeopathy as an adjunct to periodontal treatment improves local and systemic clinics and can provide better health conditions for patients with or without T2D.
Assuntos
Periodontite Crônica , Diabetes Mellitus Tipo 2 , Homeopatia , Adulto , Idoso , Brasil , Periodontite Crônica/tratamento farmacológico , Diabetes Mellitus Tipo 2/tratamento farmacológico , Feminino , Humanos , Masculino , Compostos de Mercúrio , Pessoa de Meia-IdadeRESUMO
The original manuscript of Casanova's Memoirs is stored at the Bibliothèque Nationale de France in Paris. We have gained access to it and explored the surfaces of chapters one and two (via the ethylene vinyl acetate [EVA] film technology, i.e., of diskettes of ethylene vinyl acetate with embedded strong cation and anion exchangers and C8 resins) in search of potential diseases of the author, especially of the gonorrhea bacterium, since Casanova reported that he had several bouts of this pathology along his adventurous life. Although the bacterium was not found, we have detected high levels of HgS as red spots along the lines of the manuscript, suggesting that Casanova was using this chemical as a cure for his venereal disease. Additionally, among the several bacteria identified on the surface via mass spectrometry, we could detect traces of Streptococcus uberis, a typical animal infection, found also in humans, together with a few strains of Lactobacilli, probably present in his saliva. The EVA film technology appears to open new horizons for investigating the world Cultural Heritage.
Assuntos
Livros/história , Tipagem Molecular/métodos , Redação/história , Proteínas de Bactérias/análise , Proteínas de Bactérias/química , Proteínas de Bactérias/classificação , França , História do Século XVIII , Humanos , Lactobacillus/química , Espectrometria de Massas/métodos , Compostos de Mercúrio/análise , Compostos de Mercúrio/química , Polivinil , Streptococcus/químicaRESUMO
Online chemically sensitive detectors for size exclusion chromatography (SEC) through coupled setups based on infrared (IR) (or NMR) spectrometers present new possibilities through unprecedented levels of polymer detail with respect to molecular weight and chemical composition. Herein, a new external cavity quantum cascade laser (EC-QCL) mid-IR spectrometer as a chemically sensitive online detector for SEC is custom-designed, built, and tested. This unique spectrometer features multiple broadly tunable EC-QCL sources, which can be operated in continuous wave and pulsed mode, accompanied with balanced liquid nitrogen cooled mercury cadmium telluride (MCT) detectors and a new custom-built transmission flow cell. Automated data analysis is done with a self-written MATLAB code. The limit of detection (LOD) is measured online, coupled with SEC chromatography, where on average, one carbonyl functionality in 530 000 g mol-1 at chromatographic conditions for SEC could be detected. It is possible to detect 0.46 µg (LOD) PMMA, which is approximately a factor of 30 lower than that reported for SEC-Fourier transform infrared.
Assuntos
Cromatografia em Gel/métodos , Lasers Semicondutores , Polímeros/química , Compostos de Cádmio/química , Compostos de Mercúrio/química , Peso Molecular , Polímeros/análise , Espectrofotometria Infravermelho/métodosRESUMO
Silver nanoparticles, used mainly for their antibacterial properties, are among the most common manufactured nanomaterials. How they interact with aquatic organisms, especially how they cross biological membranes, remains uncertain. Free Ag+ ions, released from these nanoparticles, are known to play an important role in their overall bioavailability. In this project, we have studied the uptake of dissolved and nanoparticulate silver by liposomes. These unilamellar vesicles, composed of phospholipids, have long been used as models for natural biological membranes, notably to study the potential uptake of solutes by passive diffusion through the phospholipid bilayer. The liposomes were synthesized using extrusion techniques and were exposed over time to dissolved silver under different conditions where Ag+, AgS2O3-, or AgCl0 were the dominant species. Similar experiments were conducted with the complexes HgCl 2 0 and Cd(DDC) 2 0 , both of which are hydrophobic and known to diffuse passively through biological membranes. The uptake kinetics of Ag+, HgCl 2 0 , and Cd(DDC) 2 0 show no increase in internalized concentrations over time, unlike AgS2O3- and AgCl0, which appear to pass through the phospholipid bilayer. These results are in contradiction with our initial hypothesis that lipophilic Hg and Cd complexes would be able to cross the membrane, whereas silver would not. Encapsulated tritiated water inside the liposomes was shown to rapidly diffuse through the lipid bilayer, suggesting a high permeability. We hypothesize that monovalent anions or complexes as well as small neutral complexes with a strong dipole can diffuse through our model membrane. Finally, liposomes were exposed to 5-nm polyvinylpyrrolidone-coated silver nanoparticles over time. No significant uptake of nanoparticulate silver was observed. Neither disruption of the membrane nor invagination of nanoparticles into the liposomes was observed. This suggests that the main risk caused by AgNPs for nonendocytotic biological cells would be the elevation of the free silver concentration near the membrane surface due to adsorption of AgNPs and subsequent oxidation/dissolution.
Assuntos
Bicamadas Lipídicas/química , Lipossomos/química , Nanopartículas Metálicas/química , Prata/química , Prata/farmacocinética , Adsorção , Organismos Aquáticos , Disponibilidade Biológica , Cátions/química , Difusão , Bicamadas Lipídicas/farmacocinética , Compostos de Mercúrio/química , Compostos de Mercúrio/farmacocinética , Fosfolipídeos/química , Poluentes Químicos da Água/químicaRESUMO
Mercury (Hg) toxicity continues to represent a global health concern. Given that human populations are mostly exposed to low chronic levels of mercurial compounds (methylmercury through fish, mercury vapor from dental amalgams, and ethylmercury from vaccines), the need for more sensitive and refined tools to assess the effects and/or susceptibility to adverse metal-mediated health risks remains. Traditional biomarkers, such as hair or blood Hg levels, are practical and provide a reliable measure of exposure, but given intra-population variability, it is difficult to establish accurate cause-effect relationships. It is therefore important to identify and validate biomarkers that are predictive of early adverse effects prior to adverse health outcomes becoming irreversible. This review describes the predominant biomarkers used by toxicologists and epidemiologists to evaluate exposure, effect and susceptibility to Hg compounds, weighing on their advantages and disadvantages. Most importantly, and in light of recent findings on the molecular mechanisms underlying Hg-mediated toxicity, potential novel biomarkers that might be predictive of toxic effect are presented, and the applicability of these parameters in risk assessment is examined.
Assuntos
Exposição Ambiental/efeitos adversos , Poluentes Ambientais/toxicidade , Compostos de Mercúrio/toxicidade , Mercúrio/toxicidade , Compostos de Metilmercúrio/toxicidade , Animais , Biomarcadores/análise , Humanos , Medição de RiscoRESUMO
Mercury pollution and its impacts on human health is of global concern. The authors of this paper were members of the Plenary Panel on Human Health in the 12th International Conference on Mercury as a Global Pollutant held in Korea in June 2015. The Panel was asked by the conference organizers to address two questions: what is the current understanding of the impacts of mercury exposure on human health and what information is needed to evaluate the effectiveness of the Minamata Convention in lowering exposure and preventing adverse effects. The authors conducted a critical review of the literature published since January 2012 and discussed the current state-of-knowledge in the following areas: environmental exposure and/or risk assessment; kinetics and biomonitoring; effects on children development; effects on adult general populations; effects on artisanal and small-scale gold miners (ASGM); effects on dental workers; risk of ethylmercury in thimerosal-containing vaccines; interactions with nutrients; genetic determinants and; risk communication and management. Knowledge gaps in each area were identified and recommendations for future research were made. The Panel concluded that more knowledge synthesis efforts are needed to translate the research results into management tools for health professionals and policy makers.
Assuntos
Exposição Ambiental , Nível de Saúde , Compostos de Mercúrio/efeitos adversos , Mercúrio/efeitos adversos , Humanos , Mercúrio/toxicidade , Medição de RiscoRESUMO
500 years of mercury (Hg) mining in the town of Idrija has caused severe pollution in Idrija and its surroundings. Following the closure of the mine in 1995, the environment remains contaminated with Hg. Sources of elemental-, inorganic- and methyl Hg exposure were identified, potential environmental level of exposure to Hg was evaluated and actual internal exposure to Hg was assessed in selected susceptible population groups comprising school-age children and pregnant women living in Idrija and in control groups from rural and urban environments. The study of pregnant women (n=31) was conducted between 2003 and 2008, and the study of school-age children (n=176) in 2008. Potential interaction of Hg with selenium (Se) in plasma was assessed in both study populations, while in pregnant women antioxidative enzyme activity (glutathione peroxidase, superoxide dismutase and catalase) in erythrocytes of maternal and cord blood was also assessed. Actual exposure to Hg as indicated by levels of Hg in children's blood (geometric mean (GM) 0.92µg/L), mother's blood (GM 1.86µg/L), children's urine (GM 1.08µg/g crea.), mother's urine (GM 2.51µg/L), children's hair (GM 241ng/g) and mother's hair (GM 251ng/g) was higher in the two study groups from Idrija than in the control groups from rural areas, but was still at the level of a "normal" population and reflects mainly exposure to elemental Hg (Hg°) from dental amalgam and, to a certain extent atmospheric Hg°. Furthermore, the internal doses of Hg received during pregnancy did not decrease the bioavailability of Se. Based on observation in children, the increase in Se protein expression is suggested to be a consequence of moderately elevated exposure to Hg°. The observed changes in activity of antioxidative enzymes, as biomarkers of oxidative stress, appear to be mainly associated with pregnancy per se and not with an increased exposure to Hg. In view of the continuing increased potential for Hg exposure and the low number of pregnant women studied, the results warrant a further longitudinal study of a larger group of pregnant women residing in the area of the former mercury mine.
Assuntos
Antioxidantes/metabolismo , Exposição Ambiental , Poluentes Ambientais/metabolismo , Compostos de Mercúrio/metabolismo , Mercúrio/metabolismo , Compostos de Metilmercúrio/metabolismo , Selênio/metabolismo , Adulto , Criança , Estudos Transversais , Monitoramento Ambiental , Poluentes Ambientais/análise , Enzimas/metabolismo , Feminino , Contaminação de Alimentos/análise , Humanos , Masculino , Mercúrio/análise , Compostos de Mercúrio/análise , Compostos de Metilmercúrio/análise , Mineração , Gravidez , Eslovênia , Adulto JovemRESUMO
Mercury accumulates at high levels in marine mammal tissues. However, its speciation is poorly understood. The main goal of this investigation was to establish the relationships among mercury species and selenium (Se) concentrations in toothed-whale muscles at different mercury levels. The concentrations of total mercury (T-Hg), methylmercury (MeHg), inorganic mercury (I-Hg) and Se were determined in the muscles of four toothed-whale species: bottlenose dolphins (n=31), Risso's dolphins (n=30), striped dolphins (n=29), and short-finned pilot whales (n=30). In each species, the MeHg concentration increased with increasing T-Hg concentration, tending to reach a plateau. In contrast, the proportion of MeHg in T-Hg decreased from 90-100% to 20-40%. The levels of T-Hg and Se showed strong positive correlations. Se/I-Hg molar ratios rapidly decreased with the increase of I-Hg and reached almost 1 in all species. These results suggested that the demethylated MeHg immediately formed Se/I-Hg equimolar complex of mercury selenide (HgSe) in their muscles. In addition, an X-ray absorption fine structure analysis (XAFS) of a bottlenose dolphin muscle confirmed that the dominant chemical form of the Se/I-Hg equimolar complex was HgSe. HgSe was mainly localized in cells near the endomysium using electron probe microanalysis (EPMA). These results suggested that the demethylated MeHg finally deposits within muscle cells of bottlenose dolphin as an inert HgSe.
Assuntos
Golfinhos/metabolismo , Mercúrio/farmacocinética , Músculos/metabolismo , Selênio/farmacocinética , Animais , Microanálise por Sonda Eletrônica , Monitoramento Ambiental , Feminino , Masculino , Compostos de Mercúrio/farmacocinética , Compostos de Metilmercúrio/farmacocinética , Compostos de Selênio/farmacocinética , Especificidade da Espécie , Poluentes Químicos da Água/farmacocinética , Espectroscopia por Absorção de Raios XRESUMO
The purpose of this review is to examine the evidence for a relationship between mercury (Hg) exposure from dental amalgams and certain idiopathic chronic illnesses--chronic fatigue syndrome (CFS), fibromyalgia (FM), depression, anxiety, and suicide. Dental amalgam is a commonly used dental restorative material that contains approximately 50% elemental mercury (Hg0) by weight and releases Hg0 vapor. Studies have shown that chronic Hg exposure from various sources including dental amalgams is associated with numerous health complaints, including fatigue, anxiety, and depression--and these are among the main symptoms that are associated with CFS and FM. In addition, several studies have shown that the removal of amalgams is associated with improvement in these symptoms. Although the issue of amalgam safety is still under debate, the preponderance of evidence suggests that Hg exposure from dental amalgams may cause or contribute to many chronic conditions. Thus, consideration of Hg toxicity may be central to the effective clinical investigation of many chronic illnesses, particularly those involving fatigue and depression.
Assuntos
Ansiedade/etiologia , Amálgama Dentário/efeitos adversos , Depressão/etiologia , Fadiga/etiologia , Compostos de Mercúrio/efeitos adversos , Suicídio , Doença Crônica , Prática Clínica Baseada em Evidências , Fibromialgia/etiologia , HumanosRESUMO
The aim of the study was to determine the prognosis and to evaluate the regression of lichenoid contact reactions (LCR) and oral lichen planus (OLP) after replacement of dental restorative materials suspected as causing the lesions. Forty-four referred patients with oral lesions participated in a follow-up study that was initiated an average of 6 years after the first examination at the Department of Odontology, i.e. the baseline examination. The patients underwent odontological clinical examination and answered a questionnaire with questions regarding dental health, medical and psychological health, and treatments undertaken from baseline to follow-up. After exchange of dental materials, regression of oral lesions was significantly higher among patients with LCR than with OLP. As no cases with OLP regressed after an exchange of materials, a proper diagnosis has to be made to avoid unnecessary exchanges of intact restorations on patients with OLP.
Assuntos
Amálgama Dentário/efeitos adversos , Líquen Plano Bucal/patologia , Erupções Liquenoides/patologia , Mucosa Bucal/patologia , Adulto , Idoso , Análise de Variância , Feminino , Seguimentos , Ligas de Ouro/efeitos adversos , Humanos , Líquen Plano Bucal/etiologia , Líquen Plano Bucal/imunologia , Erupções Liquenoides/imunologia , Masculino , Compostos de Mercúrio/efeitos adversos , Ligas Metalo-Cerâmicas/efeitos adversos , Pessoa de Meia-Idade , Mucosa Bucal/imunologia , Níquel/efeitos adversos , Indução de Remissão , Inquéritos e Questionários , Fatores de Tempo , Resultado do TratamentoRESUMO
The chemical compounds that make up gaseous oxidized mercury (GOM) in the atmosphere, and the reactions responsible for their formation, are not well understood. The limitations and uncertainties associated with the current method applied to measure these compounds, the KCl-coated denuder, are not known due to lack of calibration and testing. This study systematically compared the uptake of specific GOM compounds by KCl-coated denuders with that collected using nylon and cation exchange membranes in the laboratory and field. In addition, a new method for identifying different GOM compounds using thermal desorption is presented. Different GOM compounds (HgCl2, HgBr2, and HgO) were found to have different affinities for the denuder surface and the denuder underestimated each of these compounds. Membranes measured 1.3 to 3.7 times higher GOM than denuders in laboratory and field experiments. Cation exchange membranes had the highest collection efficiency. Thermodesorption profiles for the release of GOM compounds from the nylon membrane were different for HgO versus HgBr2 and HgCl2. Application of the new field method for collection and identification of GOM compounds demonstrated these vary as a function of location and time of year. Understanding the chemistry of GOM across space and time has important implications for those developing policy regarding this environmental contaminant.
Assuntos
Poluentes Atmosféricos/análise , Brometos/análise , Monitoramento Ambiental/instrumentação , Cloreto de Mercúrio/análise , Compostos de Mercúrio/análise , Óxidos/análise , Adsorção , Resinas de Troca de Cátion/química , Monitoramento Ambiental/métodos , Membranas Artificiais , Nylons/química , Oxirredução , Cloreto de Potássio/químicaRESUMO
Mercury is known to be a toxic material with adverse effects on the body as claimed by so many researchers and always projected a negative aspect of this element. It is true that it may cause a several problems when it exceeds the safe limit but along with its negative image, mercury has been playing a positive role in the field of medicine and dentistry. It has many therapeutic uses including various medications, ointments, dental fillings, contact lens, cosmetics, paints as well as in different instruments like thermometer and sphygmomanometers. Mercury and its compounds used in dental practice may be responsible for release of mercury into the oral cavity. Compounds of mercury tend to be much more toxic than the element itself, and organic compounds of mercury (e.g., dimethyl-mercury) are often extremely toxic and may be responsible in causing brain and liver damage.
Assuntos
Odontologia , Medicina , Compostos de Mercúrio/uso terapêutico , Mercúrio/uso terapêutico , Exposição Ambiental/efeitos adversos , Humanos , Mercúrio/efeitos adversos , Compostos de Mercúrio/efeitos adversos , Exposição Ocupacional/efeitos adversosAssuntos
Amálgama Dentário/efeitos adversos , Higienistas Dentários , Restauração Dentária Permanente/efeitos adversos , Odontólogos , Compostos de Mercúrio/efeitos adversos , Exposição Ocupacional/efeitos adversos , Saúde Ocupacional , Segurança do Paciente , Animais , Carga Corporal (Radioterapia) , Humanos , Medição de RiscoRESUMO
A new 1,3,4-oxadiazole bridging bent organic ligand, 2,5-bis{5-methyl-2-[(4-pyridyl)methoxy]phenyl}-1,3,4-oxadiazole, C(28)H(24)N(4)O(3), L, has been used to create three novel one-dimensional isomorphic coordination polymers, viz. catena-poly[[[dichloridomercury(II)]-µ-2,5-bis{5-methyl-2-[(4-pyridyl)methoxy]phenyl}-1,3,4-oxadiazole] methanol monosolvate], {[HgCl(2)(C(28)H(24)N(4)O(3))]·CH(3)OH}(n), catena-poly[[[dibromidomercury(II)]-µ-2,5-bis{5-methyl-2-[(4-pyridyl)methoxy]phenyl}-1,3,4-oxadiazole] methanol monosolvate], {[HgBr(2)(C(28)H(24)N(4)O(3))]·CH(3)OH}(n), and catena-poly[[[diiodidomercury(II)]-µ-2,5-bis{5-methyl-2-[(4-pyridyl)methoxy]phenyl}-1,3,4-oxadiazole] methanol monosolvate], {[HgI(2)(C(28)H(24)N(4)O(3))]·CH(3)OH}(n). The free L ligand itself adopts a cis conformation, with the two terminal pyridine rings and the central oxadiazole ring almost coplanar [dihedral angles = 5.994 (7) and 9.560 (6)°]. In the Hg(II) complexes, however, one of the flexible pyridylmethyl arms of ligand L is markedly bent and helical chains are obtained. The Hg(II) atom lies in a distorted tetrahedral geometry defined by two pyridine N-atom donors from two L ligands and two halide ligands. The helical chains stack together via interchain π-π interactions that expand the dimensionality of the structure from one to two. The methanol solvent molecules link to the complex polymers through O-H···N and O-H···O hydrogen bonds.
Assuntos
Brometos/química , Iodetos/química , Cloreto de Mercúrio/química , Compostos de Mercúrio/química , Oxidiazóis/química , Polímeros/química , Piridinas/química , Cristalografia por Raios X , Ligantes , Modelos Moleculares , Estrutura MolecularRESUMO
Because of the ubiquity of fluoride ions and their potential toxicity at high doses, researchers would like to design receptors that selectively detect this anion. Fluoride is found in drinking water, toothpaste, and osteoporosis drugs. In addition, fluoride ions also can be detected as an indicator of uranium enrichment (via hydrolysis of UF(6)) or of the chemical warfare agent sarin, which releases the ion upon hydrolysis. However, because of its high hydration enthalpy, the fluoride anion is one of the most challenging targets for anion recognition. Among the various recognition strategies that are available, researchers have focused a great deal of attention on Lewis acidic boron compounds. These molecules typically interact with fluoride anions to form the corresponding fluoroborate species. In the case of simple triarylboranes, the fluoroborates are formed in organic solvents but not in water. To overcome this limitation, this Account examines various methods we have pursued to increase the fluoride-binding properties of boron-based receptors. We first considered the use of bifunctional boranes, which chelate the fluoride anion, such as 1,8-diborylnaphthalenes or heteronuclear 1-boryl-8-mercurio-naphthalenes. In these molecules, the neighboring Lewis acidic atoms can cooperatively interact with the anionic guest. Although the fluoride binding constants of the bifunctional compounds exceed those of neutral monofunctional boranes by several orders of magnitude, the incompatibility of these systems with aqueous media limits their utility. More recently, we have examined simple triarylboranes whose ligands are decorated by cationic ammonium or phosphonium groups. These cationic groups increase the electrophilic character of these boranes, and unlike their neutral analogs, they are able to complex fluoride in aqueous media. We have also considered cationic boranes, which form chelate complexes with fluoride anions. Our work demonstrates that Coulombic and chelate effects are additive and can be combined to boost the anion affinity of Lewis acidic hosts. The boron compounds that we have investigated present a set of photophysical and electrochemical properties that can serve to signal the fluoride-binding event. We can also apply this approach to cyanide complexation and are continuing our investigations in that area.
Assuntos
Boranos/química , Quelantes/química , Fluoretos/química , Íons/química , Ligação de Hidrogênio , Compostos de Mercúrio/química , Estrutura Molecular , Compostos de Amônio Quaternário/químicaRESUMO
The Food and Drug Administration (FDA) published a final rule in the Federal Register of August 4, 2009 (74 FR 38686) which classified dental amalgam as a class II device, reclassified dental mercury from class I to class II, and designated special controls for dental amalgam, mercury, and amalgam alloy. The effective date of the rule was November 2, 2009. The final rule was published with an inadvertent error in the codified section. This document corrects that error. This action is being taken to ensure the accuracy of the agency's regulations.
Assuntos
Ligas Dentárias/classificação , Amálgama Dentário/classificação , Mercúrio/classificação , Aprovação de Equipamentos/legislação & jurisprudência , Humanos , Compostos de Mercúrio/classificação , Estados UnidosRESUMO
Mercury-containing dental amalgam is known to be a source of human exposure to mercury. We have explored the use of electron yield Hg L(III) X-ray absorption spectroscopy to characterize the chemical nature of dental amalgam surfaces. We find that the method is practical and that it shows extensive mercury depletion in the surface of the aged amalgam with significant differences between old and fresh amalgam surfaces. Whereas the fresh amalgam gives spectra that are typical of metallic mercury, the aged amalgam is predominantly beta-mercuric sulfide. The toxicological implications of these results are discussed.
Assuntos
Amálgama Dentário/química , Mercúrio/química , Humanos , Análise dos Mínimos Quadrados , Mercúrio/toxicidade , Compostos de Mercúrio/química , Compostos de Mercúrio/toxicidade , Espectroscopia por Absorção de Raios XRESUMO
The EPA reference dose for methylmercury (MeHg) was established using data from populations with greater exposures than those typical of the US. Few data are available on potential adverse health effects at lower levels. We examined relationships between hair mercury (Hg) levels and neuropsychological outcomes in a population of US children. This study included data from 355 children ages 6-10 enrolled in the New England Children's Amalgam Trial. Data on total hair Hg levels, sociodemographic information and neuropsychological function were collected. We evaluated associations between hair Hg and neuropsychological test scores with linear regression methods and used generalized additive models to determine the shape of associations that departed from linearity. Models controlled for relevant covariates, including the potential beneficial effects of consuming fish. In adjusted models, we observed no significant linear relationships between hair Hg level and any test score. Significant departures from linearity were identified for WIAT Math Reasoning and WRAMVA Visual-Motor Composite scores. The association was positive for hair Hg levels below 0.5 microg/g and negative for levels between 0.5 and 1.0 microg/g. Overall, test scores of children with hair Hg levels 1.0 microg/g appeared to be lower than those of children with levels < 1.0 microg/g, but few children had levels in this upper range and these differences did not reach statistical significance. Hair Hg levels below 1.0 microg/g in US school-age children were not adversely related to neuropsychological function.
Assuntos
Desenvolvimento Infantil/efeitos dos fármacos , Amálgama Dentário/toxicidade , Compostos de Mercúrio/toxicidade , Sistema Nervoso/efeitos dos fármacos , Criança , Cognição/efeitos dos fármacos , Amálgama Dentário/análise , Amálgama Dentário/química , Feminino , Cabelo/química , Humanos , Masculino , Compostos de Mercúrio/análise , Compostos de Mercúrio/farmacocinética , Modelos Estatísticos , Sistema Nervoso/crescimento & desenvolvimento , Testes Neuropsicológicos , New England , Fatores Socioeconômicos , Espectrofotometria AtômicaRESUMO
The effect of electrolyte and non-electrolyte solutions on the survival and on the morphology of zebrafish Danio rerio embryos was investigated. Embryos in different ontogenetic stages were incubated in electrolyte (NaCl, KCl, MgCl2 and CaCl2) and non-electrolyte solutions [sucrose and polyvinylalcohol (PVA)] of different concentrations for 5-15 min. The embryos were hatched to the long-pec stage and the effective concentrations which caused a 50% decrease in embryo development (EC50) were determined. The morphometric changes, which were caused by the test solutions, were measured. Ion channel blockers were used to see if active ion transport played a role for embryo survival. Finally, dechorionated embryos were exposed to the test solutions to get indications about the importance of chorion and perivitelline space. For 12 hours post fertilization (hpf) embryos and a 15 min exposure period, EC50 was highest for MgCl2 (1.60 mol l(-1)), followed by sucrose (0.73 mol l(-1)), NaCl (0.49 mol l(-1)), KCl (0.44 mol l(-1)), CaCl2 (0.43 mol l(-1)) and PVA [0.0005 mol l(-1) (2.2%)]. EC50 were lower for early embryonic stages than for advanced stages for all solutions with exception of MgCl2 and sucrose. At the EC50, MgCl2 and CaCl2 solutions did not induce morphometric changes. NaCl and sucrose solutions induced reversible morphometric changes, which were compensated within 10 min. Only the EC50 of KCl and PVA solutions induced permanent morphometric changes, which could not be compensated. Incubation of embryos in electrolyte and non-electrolyte solutions together with ouabain (blocker of Na+- K+ ATPase), HgCl3 (dose-dependent inhibition of aquaporine channels), verapamil (inhibition of calcium and magnesium uptake) and amiloride (inhibition of sodium uptake) significantly decreased the per cent of embryos developing to the long-pec stage in comparison to the same solutions without blockers. Ouabain and HgCl(3) also induced morphometric changes. For dechorionated embryos the survival rates in water and in the different test solutions were similar to untreated embryos.
Assuntos
Eletrólitos/farmacologia , Embrião não Mamífero/efeitos dos fármacos , Inibidores do Crescimento/farmacologia , Álcool de Polivinil/farmacologia , Sacarose/farmacologia , Peixe-Zebra/embriologia , Amilorida/farmacologia , Animais , Bloqueadores dos Canais de Cálcio/farmacologia , Inibidores Enzimáticos/farmacologia , Concentração Inibidora 50 , Compostos de Mercúrio/farmacologia , Ouabaína/farmacologia , Bloqueadores dos Canais de Sódio/farmacologia , Análise de Sobrevida , Fatores de Tempo , Verapamil/farmacologiaRESUMO
The Food and Drug Administration (FDA) is issuing a final rule classifying dental amalgam into class II, reclassifying dental mercury from class I to class II, and designating a special control to support the class II classifications of these two devices, as well as the current class II classification of amalgam alloy. The three devices are now classified in a single regulation. The special control for the devices is a guidance document entitled, "Class II Special Controls Guidance Document: Dental Amalgam, Mercury, and Amalgam Alloy." This action is being taken to establish sufficient regulatory controls to provide reasonable assurance of the safety and effectiveness of these devices. Elsewhere in this issue of the Federal Register, FDA is announcing the availability of the guidance document that will serve as the special control for the devices.